text:
Programmable Grit-Blasting System
NASA Technical Reports Server (NTRS)
In programmable grit-blasting system undergoing design, controller moves blasting head to precise positions to shape or remove welding defects from parts. Controller holds head in position for preset dwell time and moves head to new position along predetermined path. Position of articulated head established by pair of servomotors according to programmed signals from controller. Head similar to video borescope. Used to remove welding defects in blind holes. Suited for repetitive production operations in grit-blast box.
Burley, Richard K.
Effect of Grit Blasting on Substrate Roughness and Coating Adhesion
SciTech Connect
Statistically designed experiments were performed to compare the surface roughnesses produced by grit blasting A36/1020 steel with different abrasives. Grit blast media, blast pressure, and working distance were varied using a Box-type statistical design of experiment (SDE) approach. The surface textures produced by four metal grits (HG16, HG18, HG25, and HG40) and three conventional grits (copper slag, coal slag, and chilled iron) were compared. Substrate roughness was measured using surface profilometry and correlated with operating parameters. The HG16 grit produced the highest surface roughness of all the grits tested. Aluminum and zinc-aluminum coatings were deposited on the grit-blasted substrates using a Twin-Wire Electric Arc (TWEA) process. Bond strength of the coatings was measured with a portable adhesion tester in accordance with ASTM standard D4541. The coatings on substrates roughened with steel grit exhibit superior bond strength to those on substrates prepared with conventional grit. For aluminum coatings sprayed onto surfaces prepared with the HG16 grit, the bond strength was most influenced by current, spray distance, and spray gun pressure (in that order). The highest bond strength for the zinc-aluminum coatings was attained on surfaces prepared using the metal grits.
Dominic Varacalle; Donna Guillen; Doug Deason; William Rhodaberger; Elliott Sampson
The primary purpose of grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents statistically designed experiments that were accomplished to investigate the effect of abrasives on roughness for A36/1020 steel. The experiments were conducted using a Box statistical design of experiment (SDE) approach. Three grit blasting parameters and their effect on the resultant substrate roughness were investigated. These include blast media, blast pressure, and working distance. The substrates were characterized for roughness using surface profilometry. These attributes were correlated with the changes in operating parameters. Twin-Wire Electric Arc (TWEA) coatings of aluminum and zinc/aluminum were deposited on the grit-blasted substrates. These coatings were then tested for bond strength. Bond strength studies were conducted utilizing a portable adhesion tester following ASTM standard D4541.
Donna Post Guillen; D. J. Varacalle, Jr.; D. Deason; W. Rhodaberger; E. Sampson
Metallurgical Evaluation of Grit Blasted Versus Non-Grit Blasted Iridium Alloy Clad Vent Set Cup Surfaces
Microsoft Academic Search
Metallurgical evaluations were conducted to determine what, if any, grain size differences exist between grit blasted and non-grit blasted DOP-26 iridium alloy cup surfaces and if grit blasting imparts sufficient compressive cold work to induce abnormal grain growth during subsequent temperature exposures. Metallographic measurements indicated that grit blasting cold worked the outside cup surface to a depth of approximately 19
George B Ulrich; Hu Foster Longmire
Effect of grit-blasting on substrate roughness and coating adhesion
NASA Astrophysics Data System (ADS)
Statistically designed experiments were performed to compare the surface roughness produced by grit blasting A36/1020 steel using different abrasives. Grit blast media, blast pressure, and working distance were varied using a Box-type statistical design of experiment (SDE) approach. The surface textures produced by four metal grits (HG16, HG18, HG25, and HG40) and three conventional grits (copper slag, coal slag, and chilled iron) were compared. Substrate roughness was measured using surface profilometry and correlated with operating parameters. The HG16 grit produced the highest surface roughness of all the grits tested. Aluminum and zinc-aluminum coatings were deposited on the grit-blasted substrates using the twin-wire electric are (TWEA) process. Bond strength of the coatings was measured with a portable adhesion tester in accordance with ASTM standard D 4541. The coatings on substrates roughened with steel grit exhibit superior bond strength to those prepared with conventional grit. For aluminum coatings sprayed onto surfaces prepared with the HG16 grit, the bond strength was most influenced by current, spray distance, and spray gun pressure (in that order). The highest bond strength for the zinc-aluminum coatings was attained on surfaces prepared using the metal grits.
Varacalle, Dominic J.; Guillen, Donna Post; Deason, Douglas M.; Rhodaberger, William; Sampson, Elliott
Erosion-Resistant Water-And-Grit-Blasting Assembly
Nozzle assembly adds abrasive particles to high-pressure water jet. Abrasive nozzle combined with high-pressure tapered stripping nozzle and standard connector. Partial vacuum in relatively large chamber of abrasive-injector housing entrains grit particles from abrasive supply.
Roberts, Marion L.; Rice, R. M.; Cosby, S. A.
Surface preparation via grit-blasting for thermal spraying
The major reason for grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents five statistically designed experiments that were accomplished to investigate the grit blasting process. The experiments were conducted using a Box statistical design of experiment (SDE) approach. A substantial range of grit blasting parameters and their effect on the resultant substrate roughness were investigated, including grit type, pressure, working distance, and exposure time. The substrates were characterized for surface characteristics using image analysis. These attributes are correlated with the changes in operating parameters. Optimized process parameters for the two machines used in this study as predicted by the SDE analysis are presented.
Varacalle, D.J. Jr.; Lundberg, L.B.; Hartley, R.S. [and others
Thermal reclamation of spent blasting abrasive
Abrasive blasting media is used to remove anticorrosive and antifoulant coatings from the hulls and tanks of US Navy ships. The total production of paint-contaminated spent abrasives from the eight US. Navy shipyards ranges from 75,000 to 100,000 tons per year. Most of this spent abrasive is disposed in landfills. Organic paint binders and heavy metals are present in the spent abrasives in concentrations sufficient to classify them as hazardous wastes in some states. In an effort to avoid the rising costs an long-term environmental liability associated with landfilling this waste, the US Navy has investigated various methods of reclaiming spent abrasives for reuse in hull- and tank-blasting operations. This paper discusses the results of a research and development project conducted under the Navy's Hazardous Waste Minimization Program to test a fluidized-bed sloped-grid (FBSG) reclaimer to determine if it could be used to recycle spent abrasive. Thirty tons of abrasive were processed and a product meeting military specifications for new abrasives was reclaimed. Blasting performance was also comparable to new abrasives. 3 refs., 1 fig., 2 tabs.
Bryan, B.G. (Institute of Gas Technology, Chicago, IL (USA)); Thomas, W.; Adema, C. (David Taylor Research Center, Annapolis, MD (USA))
Alumina grit blasting parameters for surface preparation in the plasma spraying operation
This paper examines how the grit blasting process influences the surface roughness of different sub-strates, the grit residue, and the grit erosion. The influence of grit blasting conditions on induced sub-strate residual stresses is also discussed. Aluminum alloy, cast iron, and hard steel were blasted with white alumina grits of 0.5,1, and 1.4 mm mean diameters. Grit blasting was performed using either a suction-type or a pressure-type machine equipped with straight nozzles made of B4C. The influence of the follow-ing parameters was studied: grit blasting distance (56 to 200 mm), blasting time (3 to 30 s), angle between nozzle and blasted surface (30�, 60�, 90�), and blasting pressure (0.2 to 0.7 MPa). The roughness of the substrate was characterized either by using a perthometer or by image analysis. The grit residue remain-ing at the blasted surface was evaluated after cleaning by image analysis. The residual stresses induced by grit blasting were determined by using the incremental hole drilling method and by measuring the de-flection of grit-blasted beams. Grit size was determined to be the most important influence on roughness. The average values of Ra and Rt and the percentage of grit residue increased with grit size as well as the depth of the plastic zone under the substrate. An increase of the pressure slightly increased the values of �a and Rt but also promoted grit breakdown and grit residue. A blasting time of 3 to 6 s was sufficient to obtain the highest roughness and limit the grit breakdown. The residual stresses generated under the blasted surface were compressive, and the depth of the affected zone depended on the grit diameter, the blasting pressure, and the Young�s modulus of the substrate. More-over, the maximum residual stress was reached at the limit of the plastic zone (i.e., several tenths of a mil-limeter below the substrate surface).
Mellali, M.; Grimaud, A.; Leger, A. C.; Fauchais, P.; Lu, J.
Diffuse reflectance FTIR of stains on grit blasted metals
Diffuse reflectance mid-infrared Fourier transform (DRIFT) spectroscopy has been applied to the detection of oil contamination on grit-blasted metals. The object of this application is to detect and discriminate between silicone and hydrocarbon oil contamination at levels approaching 10 mg m{sup {minus}2}. A portable FTIR spectrometer with dedicated diffuse reflectance optics was developed for this purpose. Using translation devices positioned by instructions from the spectrometer operating system, images of macroscopic substrates were produced with millimeter spatial resolution. The pixels that comprise an image are each a full mid-infrared spectrum with excellent signal-to-noise, each determined as individual files and uniquely saved to disc. Reduced spectra amplitudes, based on peak height, area, or other chemometric techniques, mapped as a function of the spatial coordinates of the pixel are used to display the image. This paper demonstrates the application of the technique to the analysis of stains on grit-blasted metals, including the calibration of the method, the inspection of substrates, and the migration of oil contamination. {copyright} {ital 1998 American Institute of Physics.}
Powell, G.L.; Hallman, R.L. Jr.; Cox, R.L. [Oak Ridge Centers for Manufacturing Technologies, P.O. Box 2009, Oak Ridge, Tennessee 37831-8096 (United States)
Diffuse reflectance mid-infrared Fourier transform (DRIFT) spectroscopy has been applied to the detection of oil contamination on grit-blasted metals. The object of this application is to detect and discriminate between silicone and hydrocarbon oil contamination at levels approaching 10 mg/m{sup 2}. A portable FTIR spectrometer with dedicated diffuse reflectance optics was developed for this purpose. Using translation devices positioned by instructions from the spectrometer operating system, images of macroscopic substrates were produced with millimeter spatial resolution. The pixels that comprise an image are each a full mid-infrared spectrum with excellent signal-to-noise, each determined as individual files and uniquely saved to disc. Reduced spectra amplitudes, based on peak height, area, or other chemometric techniques, mapped as a function of the spatial coordinates of the pixel are used to display the image. This paper demonstrates the application of the technique to the analysis of stains on grit-blasted metals, including the calibration of the method, the inspection of substrates, and the migration of oil contamination.
Powell, G.L.; Hallman, R.L. Jr.; Cox, R.L. [Oak Ridge Centers for Manufacturing Technologies, TN (United States)
Blasting sand is used for abrasive blasting, but its inhalation is associated with pulmonary inflammation and fibrosis. Consequently, safer substitute materials for blasting sand are needed. In a previous study from this laboratory, the comparative pulmonary toxicity of five abrasive blasting substitutes and blasting sand was reported. In this study, the pulmonary toxicity of blasting sand was compared to five
Dale W. Porter; Ann F. Hubbs; Victor A. Robinson; Lori A. Battelli; Mark Greskevitch; Mark Barger; Douglas Landsittel; William Jones; Vincent Castranova
Recycled Steel Abrasive Grit. Evaluation of Rounding and its Effects on Adhesion.
National Technical Information Service (NTIS)
The use of recycled metallic abrasives (e.g., steel grit) is becoming more common on U.S. Army Corps of Engineers (COE) projects for preparation of steel surfaces prior to application of thermal-sprayed metallic and liquid- applied coatings. The angularit...
A. D. Beitelman
Abrasive Blasting Agents: Designing Studies to Evaluate Relative Risk
Workers exposed to respirable crystalline silica used in abrasive blasting are at increased risk of developing a debilitating and often fatal fibrotic lung disease called silicosis. The National Institute for Occupational Safety and Health (NIOSH) recommends that silica sand be prohibited as abrasive blasting material and that less hazardous materials be used in blasting operations. However, data are needed on
Ann Hubbs; Mark Greskevitch; Eileen Kuempel; Fernando Suarez; Mark Toraason
Creep feed profile grinding of Ni-based superalloys with ultrafine-polycrystalline cBN abrasive grits
This paper presents the grinding characteristics of a newly developed ultrafine-polycrystalline cBN abrasive grit in creep feed profile grinding of Nickel-based superalloys. Experiments for producing a rectangular-shaped groove on a flat surface in one pass by creep feed grinding have been carried out using the new polycrystalline cBN (PcBN-U) grit and a representative conventional monocrystalline cBN (McBN-B1) grit. The grinding
Y Sunarto; Yoshio Ichida
Acid Etching and Plasma Sterilization Fail to Improve Osseointegration of Grit Blasted Titanium Implants
PubMed Central
Interaction between implant surface and surrounding bone influences implant fixation. We attempted to improve the bone-implant interaction by 1) adding surface micro scale topography by acid etching, and 2) removing surface-adherent pro-inflammatory agents by plasma cleaning. Implant fixation was evaluated by implant osseointegration and biomechanical fixation. The study consisted of two paired animal sub-studies where 10 skeletally mature Labrador dogs were used. Grit blasted titanium alloy implants were inserted press fit in each proximal tibia. In the first study grit blasted implants were compared with acid etched grit blasted implants. In the second study grit blasted implants were compared with acid etched grit blasted implants that were further treated with plasma sterilization. Implant performance was evaluated by histomorphometrical investigation (tissue-to-implant contact, peri-implant tissue density) and mechanical push-out testing after four weeks observation time. Neither acid etching nor plasma sterilization of the grit blasted implants enhanced osseointegration or mechanical fixation in this press-fit canine implant model in a statistically significant manner.
Saks?, Mikkel; Jakobsen, Stig S; Saks?, Henrik; Baas, J?rgen; Jakobsen, Thomas; S?balle, Kjeld
Comparative Pulmonary Toxicity of 6 Abrasive Blasting Agents
Inhalation of silica dust is associated with pulmonary fibrosis. Therefore, substitute abrasive materials have been suggested for use in abrasive blasting operations. To date, toxicological evalua- tion of most substitute abrasives has been incomplete. Therefore, the objective of this study was to compare the pulmonary toxicity of a set of substitute abrasives (garnet, staurolite, coal slag, spec- ular hematite, and
A. F. Hubbs; N. S. Minhas; W. Jones; M. Greskevitch; L. A. Battelli; D. W. Porter; W. T. Goldsmith; D. Frazer; D. P. Landsittel; J. Y. C. Ma; M. Barger; K. Hill; D. Schwegler-Berry; V. A. Robinson; V. Castranova
Analysis of Abrasive Blasting of DOP26 Iridium Alloy
The effects of abrasive blasting on the surface geometry and microstructure of DOP-26 iridium alloy (Ir-0.3% W-0.006% Th 0.005% Al) have been investigated. Abrasive blasting has been used to control emissivity of components operating at elevated temperature. The effects of abrasive blasting conditions on surface morphology were investigated both experimentally and by numerical modeling. The simplified model, based on finite
Evan Keith Ohriner; Wei Zhang; George B Ulrich
National Shipbuilding Research Program. User's Guide to Selection of Blasting Abrasives -- Final Report.
The purpose of this guide for abrasive selection is: through proper abrasive selection shipyards can improve productivity, reduce waste, and decrease the costs associated with abrasive blast cleaning. Abrasive blasting is generally acknowledged to be the ...
Effect of grit blasting on the stress corrosion cracking behavior of line pipe steel
The beneficial effect of grit blasting is demonstrated by experiments in which the threshold stress for SCC was determined for various blasting conditions. Although the introduction of compressive stresses, surface deformation and mill scale removal all contribute to the increase in SCC resistance, removal of mill scale on the surface had the most significant effect.
G. H. Koch; T. J. Barlo; W. E. Berry
Modelling and evaluation of the micro abrasive blasting process
Micro abrasive blasting (MAB) is becoming an important machining technique for the cost effective fabrication of micro devices. The material removal process is based on the erosion of a mask-protected brittle substrate by an abrasive-laden air jet. To exploit the potentials of this technique for applications of industrial interest, the blasting process has to become more efficient and better predictable.
M. Achtsnick; P. F. Geelhoed; A. M. Hoogstrate; B. Karpuschewski
The effects of grit-blasting on surface properties for adhesion
A detailed study of the effects of grit blasting with different alumina grits on the surface characteristics of mild steel and aluminium alloy substractes is reported. Non-contacting 3D-laser profilometry was used to characterise surface texture, and surface energy was measured by static contact angle techniques. The chemical composition of the surface was determined by XPS analysis. Adhesion characteristics were investigated
A. F. Harris; A. Beevers
Recycling Contaminated Spent Blasting Abrasives in Portland Cement Mortars Using Solidification/Stabilization Technology.
The use of abrasive blasting to remove lead-based paint from steel bridges produces contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency. If the spent abrasives leach lead, chromium, and cadmium ...
B. K. Salt R. L. Carrasquillo R. C. Loehr D. W. Fowler
Atmospheric particulate emissions from dry abrasive blasting using coal slag.
Coal slag is one of the widely used abrasives in dry abrasive blasting. Atmospheric emissions from this process include particulate matter (PM) and heavy metals, such as chromium, lead, manganese, nickel. Quantities and characteristics of PM emissions depend on abrasive characteristics and process parameters. Emission factors are key inputs to estimate emissions. Experiments were conducted to study the effect of blast pressure, abrasive feed rate, and initial surface contamination on total PM (TPM) emission factors for coal slag. Rusted and painted mild steel surfaces were used as base plates. Blasting was carried out in an enclosed chamber, and PM was collected from an exhaust duct using U.S. Environment Protection Agency source sampling methods for stationary sources. Results showed that there is significant effect of blast pressure, feed rate, and surface contamination on TPM emissions. Mathematical equations were developed to estimate emission factors in terms of mass of emissions per unit mass of abrasive used, as well as mass of emissions per unit of surface area cleaned. These equations will help industries in estimating PM emissions based on blast pressure and abrasive feed rate. In addition, emissions can be reduced by choosing optimum operating conditions. PMID:16933653
Kura, Bhaskar; Kambham, Kalpalatha; Sangameswaran, Sivaramakrishnan; Potana, Sandhya
Nondestructive thermoelectric evaluation of the grit blasting induced effects in metallic biomaterials
Grit blasting is a surface treatment process widely used to enhance mechanical fixation of the implants through increasing their roughness. Test samples of two metallic biomaterial alloys such 316LVM and Ti6Al4V were blasted by projecting Al2O3 and ZrO2 particles which yield a coarse and a fine rough surface. Then, the blasted samples were thermally treated before and after partial stress relaxation and measured by non-destructive thermoelectric techniques (NDTT), the non-contacting and contacting thermoelectric power (TEP) measurements respectively. It has been found that the TEP measurements are associated directly with the subtle material variations such as cold work and compressive residual stresses due to plastic deformation produced by grit blasting. The TEP measurements clearly demonstrate that the non-contact NDTT technique is very sensitive to the reverse transformation of the ?'-martensite (blasted 316LVM) and the expected relaxation of compressive residual stresses with increasing the severity of the thermal treatment (blasted 316LVM and Ti-6Al-4V), while the contact NDTT results are closely related to grain size refinement and work hardening.
Carreon, H.; Ruiz, A.; Barriuso, S.; Gonz�lez-Carrasco, J. L.; Caballero, F. G.; Lieblich, M.
Prediction of depth removal in leather surface grit blasting using neural networks and Box-Behnken design of experiments
In this work, leather material is for the first time prepared by grit blasting process in order to improve peel strength when\\u000a bonding. Peel tests show that it is the surface depth of removal rather than surface roughness that dominates the bonding\\u000a performance. Therefore, measurement of surface removal is critical for surface preparation of using a grit blasting process.\\u000a Indirect
Zhongxu Hu; Robert Bicker; Chris Marshall
Defect analysis of grit-blasted or spray-painted surface using Vision Sensing Techniques
The paper discusses a vision-based framework for the analysis of defects on a grit-blasted or spray-painted metal surface. The system employs commodity, off-the-shelf hardware and tailor-made software, with user- friendly interface, making it cost effective yet accurate. A picture of the surface (1mx1m) is captured by a colour CCD camera and processed by a Frame Grabber card at a resolution
G. Sen Gupta; Chris Messom; Serge Demidenko; Subhas Mukhopadhyay
Shot peening, grit blasting make pipe steels more resistant to stress-corrosion cracking
Shot peening or grit blasting to one of several controlled conditions is an effective means of increasing the resistance of pipeline steels to stress-corrosion cracking (SCC). Though the principal benefit is to increase the threshold stress for SCC, mill-scale removal and a good coating anchor pattern provide added benefits. Five principal factors influence the initiation and growth rate of stress-corrosion
T. J. Barlo; R. R. Fessler
Bioceramic inlays do not improve mechanical incorporation of grit-blasted titanium stems in the proximal sheep femur.
The aim of the present study was to determine, if bioactive glass (BG) surface inlays improve osseointegration of titanium implants in the proximal femur of adult sheep. In simulation of uncemented primary stems (nine animals), only the proximal part of the implants was grit-blasted and three surface slots of the grit-blasted region were filled with sintered BG microspheres. Primary stems were implanted using press-fit technique. In revision stem simulation (eight animals), grit-blasting was extended over the whole implant and seven perforating holes of the stem were filled by sintered BG granules. Revision stems were implanted with a mixture of autogenous bone graft and BG granules. Comparison with solid partially or fully grit-blasted control stems implanted in the contralateral femurs was performed in the primary and revision stem experiments at 12 and 25 weeks, respectively. Implant incorporation was evaluated by torsional failure testing and histomorphometry. Only one-third of the primary stems anchored mechanically to bone. The revision stems incorporated better and the BG inlays of the revision stems showed ingrowth of new bone. However, there were no significant differences in the torsional failure loads between the stems with BG inlays and the control stems. In conclusion, surface BG inlays gave no measurable advantage in mechanical incorporation of grit-blasted titanium implants. Overall, the proximal sheep femur, characterized by minimal amount of cancellous bone and the presence of adipocytic bone marrow, seemed to present compromised bone healing conditions. PMID:19437438
Ker�nen, Pauli; Koort, Jyri; It�l�, Ari; Yl�nen, Heimo; Dalstra, Michel; Hupa, Mikko; Kommonen, Bertel; Aro, Hannu T
Copper slag: optimization of productivity and consumption for cleaner production in dry abrasive blasting
Copper slag, a by-product from copper smelting industry, is widely used as an abrasive material to remove rust, old coating and other contamination in dry abrasive blasting which is an expensive process and results in significant amounts of particulate emissions and spent abrasive. This paper presents models developed to improve productivity and consumption of copper slag as functions of blast
K. Kambham; S. Sangameswaran; S. R. Datar; B. Kura
Surface assessment and modification of concrete using abrasive blasting
Composite systems are applied to concrete substrates to strengthen and extend the service life. Successful restoration or rehabilitation requires surface preparation prior to the application of the overlay. Surface coatings, waterproofing systems, and other external surface applications also require surface preparation prior to application. Abrasive blast media is often used to clean and uniformly roughen the substrate. The appropriate surface roughness is necessary to facilitate a strong bond between the existing substrate and overlay. Thus, surface modification using abrasive blast media (sand and dry ice), their respective environmental effects, surface roughness characterization prior to and after blasting, and the adhesion between the substrate and overlay are the focus of this dissertation. This dissertation is comprised of an introduction, a literature review, and four chapters, the first of which addresses the environmental effects due to abrasive blasting using sand, water, and dry ice. The assessment considered four response variables: carbon dioxide (CO2) emissions, fuel and energy consumption, and project duration. The results indicated that for sand blasting and water jetting, the primary factor contributing to environmental detriment was CO22 emissions from vehicular traffic near the construction site. The second chapter is an analysis of the International Concrete Repair Institute's (ICRI) concrete surface profiles (CSPs) using 3-D optical profilometry. The primary objective was to evaluate the suitability of approximating the 3-D surface (areal) parameters with those extracted from 2-D (linear) profiles. Four profile directions were considered: two diagonals, and lines parallel and transverse to the longitudinal direction of the mold. For any CSP mold, the estimation of the 3-D surface roughness using a 2-D linear profile resulted in underestimation and overestimation errors exceeding 50%, demonstrating the inadequacy of 2-D linear profiles to approximate the 3-D concrete surface profiles. The errors were reduced when a weighted average of the four linear profiles approximated the corresponding 3-D parameter. The following chapter considers the parametric and sensitivity of concrete surface topography measurements. The weighted average of the four 2-D profiles consistently resulted in underestimation of the corresponding 3-D parameters: the dispersion of surface elevations (Sq) and the roughness (Sa). Results indicated the 3-D parameter, Sq, had the least sensitivity to data point reduction. The final chapter investigated surface modification using dry ice and sand blasting. The overall objective was to evaluate the change in the 3-D surface roughness (Sa) following blasting as functions of mix design and as induced by freeze-thaw cycling, and to compare the results obtained using dry ice with those obtained using sand as the blasting media. In general, sand blasting produced larger changes in Sa compared to dry ice blasting for the concrete mix designs considered. The primary mechanism responsible for altering the surface topography of the concrete was the scaling of the superficial cement paste layer on the exposed surface, which was due to freeze-thaw cycling. The largest relative change in roughness following blasting occurred in the control samples, which had not undergone freeze-thaw cycling.
Millman, Lauren R.
Investigation of Abrasiveness Property of Blast Furnace Slag on Ceramic Coatings via the Abrasive Slurry Wear Method
In this study, the abrasiveness property of blast furnace slags emerging as a waste material in the production of crude iron was investigated. The abrasive slurry wear (ASW) method was used for experiments. For abrasiveness tests, oxides (Al2O3, Al2O3�13% TiO2, Al2O3�40%TiO2, Cr2O3), including ceramics, which is coated on the AISI 1040 medium carbon steel surface via the plasma spray coating
Yilmaz Kucuk
Bendable Extension For Abrasive-Jet Cleaning
Hard-to-reach places cleaned more easily. Extension for abrasive-jet apparatus bent to provide controlled abrasive cleaning of walls in deep cavities or other hard-to-reach places. Designed for controlled removal of penetrant inspection dyes from inside castings, extension tube also used for such general grit-blasting work as removal of scratches.
Mayer, Walter
A review of engineering control technology for exposures generated during abrasive blasting operations.
This literature review presents information on measures for controlling worker exposure to toxic airborne contaminants generated during abrasive blasting operations occurring primarily in the construction industry. The exposures of concern include respirable crystalline silica, lead, chromates, and other toxic metals. Unfortunately, silica sand continues to be widely used in the United States as an abrasive blasting medium, resulting in high exposures to operators and surrounding personnel. Recently, several alternative abrasives have emerged as potential substitutes for sand, but they seem to be underused Some of these abrasives may pose additional metal exposure hazards. In addition, several new and improved technologies offer promise for reducing or eliminating exposures; these include wet abrasive blasting, high-pressure water jetting, vacuum blasting, and automated/robotic systems. More research, particularly field studies, is needed to evaluate control interventions in this important and hazardous operation. PMID:15631059
Flynn, Michael R; Susi, Pam
Evaluation of Productivity, Consumption, and Uncontrolled Total Particulate Matter Emission Factors of Recyclable Abrasives
Dry abrasive blasting is a commonly used surface preparation operation by many process industries to clean up metallic surfaces and achieve surface finishes suitable for future adhesion. Abrasives used in this process can be recyclable or expendable. This study was undertaken to evaluate the performance of three recyclable abrasives: garnet, barshot and steel grit\\/shot in terms of productivity (area cleaned
Sivaramakrishnan Sangameswaran
Selection of Blasting Abrasives -- Data Tables (User's Guide).
Tables in this document are grouped as follows: (1) Tables of Consumption Data for Abrasives; (2) Tables of Abrasive Productivity Data; (3) Tables of Production Rate and Consumption Data for Recyclable Abrasives; (4) Tables of Production Rate Data for Abr...
Cracks in glass electrical connector headers removed by dry blasting with fine abrasive
Cracking that causes pressure leakage in glass connector headers can be alleviated by manipulating the pin bridgewire connectors. This initiates the surface and meniscus cracks. Dry blasting the header surface with a fine abrasive then removes the cracks.
Eckert, R. W.
Abrasive micro-blasting to improve surface integrity of electrical discharge machined WC�Co composite
This study investigates the improvement of surface integrity of wire electrical discharge machined (EDM) WC�Co composite by abrasive micro-blasting. The thermally damaged recast layer generated by EDM has craters, cracks, and bubbles, which deteriorate the surface mechanical properties. The micro-blasting, using 6�12 and 4�20?m size SiC abrasive, enables the removal of the recast layer and is suitable for micro mechanical
Jun Qu; Albert J. Shih; Ronald O. Scattergood; Jie Luo
Influence of Abrasive Blast Cleaning and Corrosion Inhibitors on Protective Paint Coatings.
Wet blast cleaning of steel surfaces results in flash rusting and to combat this problem, water soluble inhibitors are used. It was suggested that inhibitors could be improved and to investigate this problem, it was necessary to produce abrasive blast cle...
A. R. Amey
Recycling contaminated spent blasting abrasives in Portland cement mortars using solidification/stabilization technology. Final research report
The use of abrasive blasting to remove lead-based paint from steel bridges produces contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency. If the spent abrasives leach lead, chromium, and cadmium greater than the EPA limits, the spent abrasives are classified as hazardous and must be rendered nonhazardous prior to disposal. An alternative to disposing of spent blasting abrasives is to recycle them in an environmentally sound application. This study investigates the feasibility of recycling spent blasting abrasives in portland cement mortars using solidification/stabilization technology to produce a usable construction material. Field application guidelines for recycling spent blasting abrasives in portland cement mortars are established based upon the results of this study.
Salt, B.K.; Carrasquillo, R.L.; Loehr, R.C.; Fowler, D.W.
Recycling of paint-contaminated grit.
The impact on the environment of using paint-contaminated grit (PCG) as a partial or full replacement for sand in Portland cement mortar and asphalt concrete mixtures was investigated. The grit waste material originated from abrasive blasting of offshore steel structures. There is a major environmental concern regarding the safe disposal of the spent blasting abrasives that contain paint chips or paint particles and other debris removed from the surface of the steel structures. This work investigated the potential reuse of PCG in Portland cement concrete (PCC) and hot mix asphalt concrete. Several studies were conducted to establish the integrity of the materials containing the recycled grit. These included the chemical and physical characterization of natural sand and PCG, the assay of leaches associated with the grit material for hazardous metal contaminants, such as Cr, Cd and Pb, and the assessment of the mechanical properties of the PCG-substituted mortars by applying special tests (such as Marshall stability and determination of the flow properties) to the PCG-substituted asphalt concrete mixtures. The overall results demonstrated that the potential reuse of PCG in PCC and asphalt concrete mixtures would not pose any environmental threat and could produce several benefits, such as reduced disposal costs, protection of water sources from improper disposal practices and reduced costs in the production of natural aggregates and asphalt cement. PMID:11523444
Taha, R; al-Alawi, D; al-Nabhani, M; Pillay, A E; al-Hamdi, A
Exposure to crystalline silica in abrasive blasting operations where silica and non-silica abrasives are used.
Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both silica and non-silica products were used. The crystalline silica content of non-silica abrasives was also measured. The facilities evaluated were preparing metal products for the application of coatings, so the substrate should not have had a significant contribution to worker exposure to crystalline silica. The occupational sampling results indicate that two-thirds of the workers assessed were potentially over-exposed to respirable crystalline silica. About one-third of the measurements over the exposure limit were at the work sites using silica substitutes at the time of the assessment. The use of the silica substitute, by itself, did not appear to have a large effect on the mean airborne exposure levels. There are a number of factors that may contribute to over-exposures, including the isolation of the blasting area, housekeeping, and inappropriate use of respiratory protective equipment. However, the non-silica abrasives themselves also contain silica. Bulk analysis results for non-silica abrasives commercially available in Alberta indicate that many contain crystalline silica above the legislated disclosure limit of 0.1% weight of silica per weight of product (w/w) and this information may not be accurately disclosed on the material safety data sheet for the product. The employer may still have to evaluate the potential for exposure to crystalline silica at their work site, even when silica substitutes are used. Limited tests on recycled non-silica abrasive indicated that the silica content had increased. Further study is required to evaluate the impact of product recycling on crystalline silica content for non-silica abrasives. Measurement of blaster exposure was challenging in this study as the blasters evaluated conducted this task intermittently throughout the work shift, frequently removing their blasting helmets. In spite of the challenges in accurately measuring blaster exposure, the measurements were still, for the most part, over the 8-h OEL. Further work is required to develop more effective sampling strategies to evaluate blaster exposure over the full work shift when task-based monitoring is not practical. PMID:24353009
Radnoff, Diane L; Kutz, Michelle K
Demonstration experience with an abrasive blasting technique for decontaminating concrete pads
A demonstration was performed for decontaminating a radioactivity contaminated concrete pad with a portable abrasive blasting system. The system utilizes a rotating blast wheel that scours the concrete surface with metal abrasive. The metal abrasive, pulverized concrete dust, and contaminants rebound into a separator chamber. The reusable metal abrasive is recycled, and the pulverized media are removed to an integral dust collection system. The exhaust is HEPA filtered to minimize release of airborne contaminants. However, the technique had limited success in reducing contamination around the cracks and seams in the concrete where the higher activity levels of contamination were detected during the radiological survey before the cleanup. The technique can be successful and cost-effective in decontaminating large areas of low contamination; however, careful characterization and planning are necessary. 3 refs., 3 figs., 1 tabs.
Devgun, J.S. (Argonne National Lab., IL (USA)); Land, R.R. (Bechtel National, Inc., Oak Ridge, TN (USA)); Doane, R.W. (TMA/Eberline, Oak Ridge, TN (USA))
Application of Abrasive-Waterjets for Machining Fatigue-Critical Aircraft Aluminum Parts
The effects of dry-grid blasting of AWJ-machined dog-bone specimens of aircraft aluminum with aluminum oxide abrasives were investigated in terms of enhancement in fatigue performance and mitigating concerns of abrasive contamination. Results obtained from fatigue tests have indicated that the surface roughness, Ra, of AWJ-induced striations is inversely proportional to the fatigue life. The fatigue life of AWJ-machined and baseline specimens, excluding those processed with dry-grit blasting, decreases with the increase in Ra. Removal of the striations with dry-grit blasting until they disappear visually only reduces Ra from 3.5 to 2.4 ?m and is still higher than that of the conventionally machined edges with Ra = 1.6 ?m. From the surface roughness point of view, the fatigue life of the dry-grit blasted specimens should not have exceeded that of the baseline counterparts. Yet the dry-grit blasting process has extended the fatigue life of the AWJ-machined specimens and the baseline counterparts by more than four and three times, respectively. The extraordinary boost in the fatigue performance is believed to be attributed to the induction of residual compressive stresses by dry-grit blasting. Such a belief was subsequent confirmed quantitatively through measurements of residual compressive stresses. Dry-grid blasting can be carried out efficiently and cost effectively by stacking AWJ-machined parts together. The benefits gained from dry-grit blasting simply outweigh the marginal cost increase.
Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.; Zeng, J.
Study on cylindrical magnetic abrasive finishing using unbonded magnetic abrasives
The process principle and the finishing characteristics of unbonded magnetic abrasive within cylindrical magnetic abrasive finishing are described in this study. The unbonded magnetic abrasive is a mechanical mixture of SiC abrasive and ferromagnetic particles with a SAE30 lubricant. Iron grit and steel grit, for which three various particle sizes were prepared for both, were used as ferromagnetic particles, each
Geeng-Wei Chang; Biing-Hwa Yan; Rong-Tzong Hsu
The effect of abrasive blasting on the strength of a joint between dental porcelain and metal base.
This paper presents the effect of selected parameters of abrasive blasting on the strength of a joint between dental porcelain and metal base. Experiments were conducted for different grain sizes of abrasive material and different blasting angles, with a constant blasting pressure. InLine dental porcelain was fused on samples of cobalt-chromium alloy following abrasive blasting; they were subsequently subjected to shearing forces on a testing machine. The fractures were observed under an electron scanning microscope in order to determine the character and course of fracturing. Strength tests showed that the grain size of abrasive material was a parameter with the greatest effect on the strength. The best effects were achieved for samples subjected to abrasive blasting with material with grain size of 110 ?m. No statistically significant differences were found for the strength of samples worked at different angles. The results of the fractographic examinations have shown that in all the samples, fracturing occurred mainly along the porcelain-metal boundary, with few cases of fracturing through porcelain. PMID:24708248
Pietnicki, Krzysztof; Wo?owiec, Emilia; Klimek, Leszek
Health Hazard Evaluation Report: HETA-2001-0279-3163, September 2012. Evaluation of Air Sampling Methods for Abrasive Blasting - Louisiana.
NIOSH received a request for an HHE from the management at a Louisiana shipyard to evaluate sampling methods for measuring employee PBZ exposures during abrasive blasting. On July 20, 2001, NIOSH investigators collected side-by-side PBZ air samples using ...
D. Ceballos D. Sylvain M. Kiefer
Effects of Grit Blasting and Annealing on the High-Temperature Oxidation Behavior of Austenitic and Ferritic Fe-Cr Alloys
Grit blasting (corundum) of an austenitic AISI 304 stainless steel (18Cr-8Ni) and of a low-alloy SA213 T22 ferritic steel (2.25Cr-1Mo) followed by annealing in argon resulted in enhanced outward diffusion of Cr, Mn, and Fe. Whereas 3 bar of blasting pressure allowed to grow more Cr2O3 and Mn x Cr3-x O4 spinel-rich scales, higher pressures gave rise to Fe2O3-enriched layers and were therefore disregarded. The effect of annealing pre-oxidation treatment on the isothermal oxidation resistance was subsequently evaluated for 48 h for both steels and the results were compared with their polished counterparts. The change of oxidation kinetics of the pre-oxidized 18Cr-8Ni samples at 850 �C was ascribed to the growth of a duplex Cr2O3/Mn x Cr3-x O4 scale that remained adherent to the substrate. Such a positive effect was less marked when considering the oxidation kinetics of the 2.25Cr-1Mo steel but a more compact and thinner Fe x Cr3-x O4 subscale grew at 650 �C compared to that of the polished samples. It appeared that the beneficial effect is very sensitive to the experimental blasting conditions. The input of Raman micro-spectroscopy was shown to be of ground importance in the precise identification of multiple oxide phases grown under the different conditions investigated in this study.
Proy, M.; Utrilla, M. V.; Otero, E.; Bouchaud, B.; Pedraza, F.
Effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of sand-blasted, large grit, acid-etched implants
Purpose The present study was performed to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on sand-blasted, large grit, acid-etched (SLA) implant surface microstructure according to varying energy levels and application times of the laser. Methods The implant surface was irradiated by the Er:YAG laser under combined conditions of 100, 140, or 180 mJ/pulse and an application time of 1 minute, 1.5 minutes, or 2 minutes. Scanning electron microscopy (SEM) was used to examine the surface roughness of the specimens. Results All experimental conditions of Er:YAG laser irradiation, except the power setting of 100 mJ/pulse for 1 minute and 1.5 minutes, led to an alteration in the implant surface. SEM evaluation showed a decrease in the surface roughness of the implants. However, the difference was not statistically significant. Alterations of implant surfaces included meltdown and flattening. More extensive alterations were present with increasing laser energy and application time. Conclusions To ensure no damage to their surfaces, it is recommended that SLA implants be irradiated with an Er:YAG laser below 100 mJ/pulse and 1.5 minutes for detoxifying the implant surfaces.
Lee, Ji-Hun; Kwon, Young-Hyuk; Herr, Yeek; Shin, Seung-Il
Fibrogenicity and carcinogenic potential of smelter slags used as abrasive blasting substitutes
This study was designed to examine the fibrogenic and carcinogenic potentials of three smelter slags (primary copper slag, secondary copper slag, and nickel slag) that have been used for a number of years as substitutes for sand in abrasive blasting operations. Seven groups of 85 male Fischer 344 rats (approximately 180 g) were used. Each group was given a single 20-mg dose of one of the following test materials via intratracheal instillation: primary copper slag, secondary copper slag, nickel slag, feldspar, Min-U-Sil, novaculite, or vehicle control. Chemical, particle size, and surface area analyses were performed for each test dust. Animals were weighed monthly, and ten animals per group were necropsied at the 6-, 12-, and 18-mo interim sacrifices. The terminal sacrifice was conducted at 22 mo. Hematoxylin and eosin stained histologic sections were prepared from designated formalin-fixed tissues collected at necropsy and examined microscopically. The pulmonary fibrogenic and carcinogenic potentials of the three smelter slags were compared histopathologically with feldspar, novaculite, Min-U-Sil, and vehicle controls. Only minimal to slight alveolar wall fibrosis was seen in the two copper slag groups, while the response seen with nickel slag was consistent with a foreign body reaction with minimal fibrosis seen in only an occasional animal. The major reaction seen in both the feldspar- and the novaculite-treated rats was a granulomatous inflammation with varying degrees of fibrosis associated with the granulomas. Significant numbers of primary lung tumors, principally adenocarcinomas and adenomas, were seen in the copper slag (p = 0.005 and p = 0.022 for the primary and secondary slags, respectively), in the feldspar (p = 0.007), in the novaculite (p less than 0.001), and in the Min-U-Sil (p less than 0.001) groups when compared to the vehicle control group.
Stettler, L.E.; Proctor, J.E.; Platek, S.F.; Carolan, R.J.; Smith, R.J.; Donaldson, H.M.
Abrasive blasting, a technique for the industrial decontamination of metal components and concrete blocks from decommissioning to unconditional release levels
When decommissioning nuclear installations, large quantities of metal components are produced as well as significant amounts of other radioactive materials, which mostly show low surface contamination. Having been used or having been brought for a while in a controlled area marks them as 'suspected material'. In view of the very high costs for radioactive waste processing and disposal, alternatives have been considered, and much effort has gone to recycling through decontamination, melting and unconditional release of metals. In a broader context, recycling of materials can considered to be a first order ecological priority in order to limit the quantities of radioactive wastes for final disposal and to reduce the technical and economic problems involved with the management of radioactive wastes. It will help as well to make economic use of primary material and to conserve natural resources of basic material for future generations. In a demonstration programme, Belgoprocess has shown that it is economically interesting to decontaminate metal components to unconditional release levels using dry abrasive blasting techniques, the unit cost for decontamination being only 30 % of the global cost for radioactive waste treatment, conditioning, storage and disposal. As a result, an industrial dry abrasive blasting unit was installed in the Belgoprocess central decontamination infrastructure. At the end of December 2006, more than 1,128 Mg of contaminated metal has been treated as well as 313 Mg of concrete blocks. The paper gives an overview of the experience relating to the decontamination of metal material and concrete blocks at the decommissioning of the Eurochemic reprocessing plant in Dessel, Belgium as well from the decontamination of concrete containers by abrasive blasting. (authors)
Gills, R.; Lewandowski, P.; Ooms, B.; Reusen, N.; Van Laer, W.; Walthery, R. [Belgoprocess N.V., Gravenstraat 73, 2480 Dessel (Belgium)
Bone-added osteotome sinus floor elevation with simultaneous placement of non-submerged sand blasted with large grit and acid etched implants: a 5-year radiographic evaluation
Purpose Implant survival rates using a bone-added osteotome sinus floor elevation (BAOSFE) procedure with simultaneous placement of a non-submerged sand blasted with large grit and acid etched (SLA) implant are well documented at sites where native bone height is less than 5 mm. This study evaluated the clinical results of non-submerged SLA Straumann implants placed at the time of the BAOSFE procedure at sites where native bone height was less than 4 mm. Changes in graft height after the BAOSFE procedure were also assessed using radiographs for 5 years after the implant procedure. Methods The BAOSFE procedure was performed on 4 patients with atrophic posterior maxillas with simultaneous placement of 7 non-submerged SLA implants. At least 7 standardized radiographs were obtained from each patient as follows: before surgery, immediately after implant placement, 6 months after surgery, every year for the next 3 years, and after more than 5 years had passed. Clinical and radiographic examinations were performed at every visit. Radiographic changes in graft height were calculated with respect to the implant's known length and the original sinus height. Results All implants were stable functionally, as well as clinically and radiographically, during the follow-up. Most of the radiographic reduction in the grafted bone height occurred in the first 2 years; reduction after 2 years was slight. Conclusions The simultaneous placement of non-submerged SLA implants using the BAOSFE procedure is a feasible treatment option for patients with severe atrophic posterior maxillas. However, the grafted bone height is reduced during the healing period, and patients must be selected with care.
Jung, Jee-Hee; Choi, Seong-Ho; Cho, Kyoo-Sung
National Shipbuilding Research Program. Reduced Volume of Spent Abrasive in Open Air Blasting.
Shipyards have been blast cleaning ships for more than 50 years. The methodology is still basically the same but numerous improvements have taken place over the years. The purpose of this project is to look at current blast cleaning technology, review wha...
W. Hitzrot
Robotic Instrument for Grinding Rocks Into Thin Sections (GRITS)
We have developed a rock grinding and polishing mechanism for in situ planetary exploration based on abrasive disks, called Grinding Rocks Into Thin Sections (GRITS). Performance characteristics and design considerations of GRITS are presented. GRITS was developed as part of a broader effort to develop an in situ automated rock thin section (ISARTS) instrument. The objective of IS-ARTS was to develop an instrument capable of producing petrographic rock thin sections on a planetary science spacecraft. GRITS may also be useful to other planetary science missions with in situ instruments in which rock surface preparation are necessary.
Paulsen, Gale; Zacny, Kris; Dreyer, Christopher B.; Szucs, Attila; Szczesiak, Matt; Santoro, Chris; Craft, Jack; Hedlund, Magnus; Skok, John
Machining of Aircraft Titanium with Abrasive-Waterjets for Fatigue Critical Applications
Laboratory tests were conducted to determine the fatigue performance of abrasive-waterjet- (AWJ-) machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results of the titanium specimens not only confirmed our previous findings in aluminum dog-bone specimens but in comparison also further enhanced the fatigue performance of the titanium. In addition, titanium is known to be difficult to cut, particularly for thick parts, however AWJs cut the material 34% faster han stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred ombination for processing aircraft titanium that is fatigue critical.
Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.
Monitoring and Testing the Parts Cleaning Stations, Abrasive Blasting Cabinets, and Paint Booths
I have the opportunity to work in the Environmental Management Office (EMO) this summer. One of the EMO's tasks is to make sure the Environmental Management System is implemented to the entire Glenn Research Center (GRC). The Environmental Management System (EMS) is a policy or plan that is oriented toward minimizing an organization's impact to the environment. Our EMS includes the reduction of solid waste regeneration and the reduction of hazardous material use, waste, and pollution. With the Waste Management Team's (WMT) help, the EMS can be implemented throughout the NASA Glenn Research Center. The WMT is responsible for the disposal and managing of waste throughout the GRC. They are also responsible for the management of all chemical waste in the facility. My responsibility is to support the waste management team by performing an inventory on parts cleaning stations, abrasive cabinets, and paint booths through out the entire facility. These booths/stations are used throughout the center and they need to be monitored and tested for hazardous waste and material. My job is to visit each of these booths/stations, take samples of the waste, and analyze the samples.
Jordan, Tracee M.
Effect of Abrasive Grit Size on Abrasive Wear.
The purpose of the M.I.T. research on wear during the calendar year 1977 was to apply the delamination theory of wear in minimizing the wear rate of splines and door hinges. The technique explored was the use of thin soft metal coatings on hard substrates...
N. P. Suh N. Saka H. C. Sin
Abrasiveness properties assessment of coated abrasives for precision belt grinding
This paper addresses a study to achieve a method of assessment of coated abrasives for precision belt grinding based on the identification of the prevailing relationships between the changing features of fixed grains on flexible coated belts and grinding performance. A set of parameters was defined which describe the aluminium oxide resin-bonded belt characteristics including active grits density, cutting edge
S. Mezghani; M. El Mansori
The abrasive machining characteristics of a glass-infiltrated alumina used for fabrication of all-ceramic dental crowns were investigated using a high-speed dental handpiece and diamond burs with different grit sizes. The material removal rate, surface roughness, and extent of edge chipping were measured as a function of grit size. The removal rate decreased substantially with decreasing bur grit size from supercoarse
Ling Yin; Lewis K. Ives; Said Jahanmir; E. Dianne Rekow; Elaine Romberg
Abrasive slurry composition for machining boron carbide
An abrasive slurry particularly suited for use in drilling or machining boron carbide consists essentially of a suspension of boron carbide and/or silicon carbide grit in a carrier solution consisting essentially of a dilute solution of alkylaryl polyether alcohol in octyl alcohol. The alkylaryl polyether alcohol functions as a wetting agent which improves the capacity of the octyl alcohol for carrying the grit in suspension, yet without substantially increasing the viscosity of the carrier solution.
Duran, E.L.
Duran, Edward L. (Santa Fe, NM)
Reducing tool wear in abrasive cutting
The abrasive Cut-Off with stationary or hand-operated machines for cutting or grinding metal is still a very common procedure in many enterprises. Because of the relatively low price of the tool �cut-off wheel� little attention is paid to the life-time of the grits. Since it is possible to obtain shape-defined grits for the production of grinding wheels an experimental study
R. Neugebauer; K.-U. Hess; S. Gleich; S. Pop
Friction and wear with a single-crystal abrasive grit of silicon carbide in contact with iron base binary alloys in oil: Effects of alloying element and its content
Sliding friction experiments were conducted with various iron-base binary alloys (alloying elements were Ti, Cr, Mn, Ni, Rh, and W) in contact with a rider of 0.025-millimeter-radius, single-crystal silicon carbide in mineral oil. Results indicate that atomic size and content of alloying element play a dominant role in controlling the abrasive-wear and -friction properties of iron-base binary alloys. The coefficient of friction and groove height (wear volume) general alloy decrease, and the contact pressure increases in solute content. There appears to be very good correlation of the solute to iron atomic radius ratio with the decreasing rate of coefficient of friction, the decreasing rate of groove height (wear volume), and the increasing rate of contact pressure with increasing solute content C. Those rates increase as the solute to iron atomic radius ratio increases from unity.
Miyoshi, K.; Buckley, D. H.
Estimation of the minimum machining performance in the abrasive waterjet machining using integrated ANN-SA
In this study, Artificial Neural Network (ANN) and Simulated Annealing (SA) techniques were integrated labeled as integrated ANN-SA to estimate optimal process parameters in abrasive waterjet (AWJ) machining operation. The considered process parameters include traverse speed, waterjet pressure, standoff distance, abrasive grit size and abrasive flow rate. The quality of the cutting of machined-material is assessed by looking to the
Azlan Mohd Zain; Habibollah Haron; Safian Sharif
Abrasive wear resistance of starch consolidated and sintered high speed steel
The abrasive wear resistance of starch consolidated (SC) and super solidus liquid phase sintered (SLPS) M3\\/2 high speed steel (HSS) samples have been evaluated by a two-body micro-abrasion test (low stress abrasion), using 6?m diamond abrasive particles, and a three-body abrasion test (high stress abrasion), using significantly larger abrasive particles of blast furnace slag (600 HV) and silicon carbide (2400
P. Harlin; M. Olsson
Abrasive Wear.
This monograph gives a general classification of the various types of wear, including abrasive wear; it describes the principles and systems of laboratory tests for abrasive wear, the regularities of this form of wear under various conditions - during fri...
M. A. Babichev M. M. Khrushchov
Abrasive Wear Study of NiCrFeSiB Flame Sprayed Coating
In the present study, abrasive wear behavior of NiCrFeSiB alloy coating on carbon steel was investigated. The NiCrFeSiB coating powder was deposited by flame spraying process. The microstructure, porosity and hardness of the coatings were evaluated. Elemental mapping was carried out in order to study the distribution of various elements in the coating. The abrasive wear behavior of these coatings was investigated under three normal loads (5, 10 and 15 N) and two abrasive grit sizes (120 and 320 grit). The abrasive wear rate was found to increase with the increase of load and abrasive size. The abrasive wear resistance of coating was found to be 2-3 times as compared to the substrate. Analysis of the scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this investigation.
Sharma, Satpal
Mineral Slag Abrasive Survey and Specification.
Because of potential silicosis problems, the U.S. shipbuilding industry has largely abandoned the use of open-air sand blasting. The predominant abrasives now being used for open-air blasting are mineral slags having a low free silica content. Concerns ab...
Abrasion of flat rotating shapes
We report on the erosion of flat linoleum �pebbles� under steady rotation in a slurry of abrasive grit. To quantify shape as a function of time, we develop a general method in which the pebble is photographed from multiple angles with respect to the grid of pixels with a digital camera. This reduces digitization noise and allows the local curvature of the contour to be computed with a controllable degree of uncertainty. Several shape descriptors are then employed to follow the evolution of different initial shapes toward a circle, where abrasion halts. The results are in good quantitative agreement with a simple model, where we propose that points along the contour move radially inward in proportion to the product of the radius and the derivative of radius with respect to angle.
Roth, A. E.; Marques, C. M.; Durian, D. J.
Plastic Media Blasting - An alternative for coating removal
Plastic Media Blasting (PMB) is a revolutionary method for the rapid and safe removal of primer, paint and even powder and other chemically resistant coatings from a vast range of products without the use of toxic chemicals or pneumatic blasting with hard abrasives. Although resembling sand-blasting, PMB does not use the hard abrasives or high pressures of that process. Instead, PMB uses reusable plastic particles which are applied at pressures of 20 to 40 psi. The unique abrasive blast media not only replaces potentially hazardous abrasives such as silica sand, but since it is reusable it also generates less overall waste material.
Abbott, Kenneth E.
Abrasive Wear of In Situ AlB2/Al-4Cu Composite Material Produced by Squeeze Casting Method
The wear behavior of a weight fraction of particles with up to 30 wt.% in situ AlB2 flakes reinforced in Al-4Cu matrix alloy composites and fabricated by a squeeze casting method was investigated in a pin-on-disk abrasion test instrument against different SiC abrasives at room conditions. Wear tests were performed under the load of 10 N against SiC abrasive papers of 80, 100, and 120 mesh grits. The effects of sliding speed, AlB2 flake content, and abrasive grit sizes on the abrasive wear properties of the matrix alloy and composites have been evaluated. The main wear mechanisms were identified using an optical microscope. The results showed that in situ AlB2 flake reinforcement improved the abrasion resistance against all the abrasives used, and the abrasive wear resistance decreased with an increase in the sliding speed and the abrasive grit size. The wear resistances of the composites were considerably bigger than those of the matrix alloy and increased with increases in in situ AlB2 flake contents.
Ficici, Ferit
Background to plastic media blasting
Chemical strippers based on active phenolic components in a chlorinated solvent have been the traditional method for removing of paints and coatings from aircraft. With the recent recognition of the environmental and health concerns of chlorinated solvents and the problem disposing of phenols there have been some major developments in paint removal technology. One of the first techniques developed to replace chemical strippers and now one of the most widely used techniques for paint removal from aircraft was plastic media blasting (PMB). The PMB technique is similar to traditional grit blasting (slag, sand alumina or carborundum) techniques used on steel and other metals (based on grits) but using polymer based media that are softer and less aggressive. Plastic media are ranked by hardness and density as well as chemical composition.
Foster, Terry
Abrasion and deformed layer formation of manganese-zinc ferrite in sliding contact with lapping tapes
Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and the deformed layers produced in single-crystal Mn-Zn ferrite simulated heads during contact with lapping tapes. The crystaline state of the head is changed drastically during the abrasion process. Crystalline states ranging from nearly amorphous to highly textured polycrystalline can be produced on the wear surface of a single-crystal Mn-Zn ferrite head. The total thickness of the deformed layer was approximately 0.8 microns. This thickness increased as the load and abrasive grit size increased. The anisotropic wear of the ferrite was found to be inversely proportional to the hardness of the wear surface. The wear was lower in the order 211 111 10 0110. The wear of the ferrite increased markedly with an increase in sliding velocity and abrasive grit size.
Miyoshi, K.; Buckley, D. H.; Tanaka, K.
Self propelled pipe blast cleaner capable of travel along a pipeline supported over the ditch
A self propelled pipe blast cleaner is described capable of travel along a pipeline supported over a ditch comprising: a self propelled cart with support rollers for movement along the top of the pipe of the pipeline being blast cleaned; variable speed drive means on the cart for driving the cart along the pipe including rollers of the support rollers; a blast cabinet mounted on the cart and surrounding the pipe for blast cleaning work along the pipe; a plurality of airless abrasive material particle blast wheels contained within the blast cabinet for abrasive material particle blast cleaning of the outer surface of the pipe as the cart is propelled along the pipe; and a blast abrasive material particle reclaiming and circulation system including a reservoir for feeding abrasive material particles to the airless blast wheels.
Hoffman, J.H.
Development of a two-body wet abrasion test method with attention to the effects of reused abradant
Abrasive wear is among the most common and costliest causes for material wastage, and it occurs in many forms. A simple method has been developed to quantify the response of metals and alloys to two-body wet abrasion. A metallographic polishing machine was modified to create a disk-on-flat sliding test rig. Adhesive-backed SiC grinding papers were used under fixed load and speed to rank the abrasive wear of seven alloy steels, some of which are candidates for drill cones for geothermal drilling. Standardized two-body abrasion tests, like those described in ASTM G132, feed unused abrasive into the contact; however, the current work investigated whether useful rankings could still be obtained with a simpler testing configuration in which specimens repeatedly slide on the same wear path under water-lubricated conditions. Tests using abrasive grit sizes of 120 and 180 resulted in the same relative ranking of the alloys although the coarser grit produced more total wear. Wear decreased when the same abrasive disk was re-used for up to five runs, but the relative rankings of the steels remained the same. This procedure was presented to ASTM Committee G2 on Wear and Erosion as a potential standard test for wet two-body abrasive wear.
Blau, Peter Julian [ORNL; Dehoff, Ryan R [ORNL
Hot-filament chemical vapor deposition of amorphous carbon film on diamond grits and induction brazing of the diamond grits
The production of a high-quality brazed diamond tool has gradually drawn the attention of the tool industry. Hot-filament chemical vapor deposition (CVD) of amorphous carbon film on diamond grits was conducted. The deposited diamond grits were used to make brazed diamond tools by induction heating. Amorphous carbon film (1-2 ?m thick) was deposited onto the diamond surface. The diamond grits protruding from the filler alloy maintain their sharpness after induction brazing of the deposited diamond grits. Discontinuous irregular carbides are distributed evenly on the brazed diamond surface in the filler alloy. This considerably enhances the bonding strength between the filler alloy and diamond grits. Grinding tests of the brazed diamond wheels show a low percentage of pullouts from the matrix and whole grain fracture for the deposited diamond grits brazed by induction heating.
Ma, Bojiang; Yu, Qingxian
Effect of workpiece properties on machinability in abrasive jet machining of ceramic materials
Abrasive jet machining (AJM), a specialized form of shot blasting using fine-grained abrasives, is an attractive micro-machining method for ceramic materials. In this paper, the machinability during the AJM process is compared to that given by the established models of solid particle erosion, in which the material removal is assumed to originate in the ideal crack formation system. However, it
M. Wakuda; Y. Yamauchi; S. Kanzaki
Grit: Perseverance and Passion for Long-Term Goals
The importance of intellectual talent to achievement in all professional domains is well established, but less is known about other individual differences that predict success. The authors tested the importance of 1 noncognitive trait: grit. Defined as perseverance and passion for long-term goals, grit accounted for an average of 4% of the variance in success outcomes, including educational attainment among
Angela L. Duckworth; Christopher Peterson; Michael D. Matthews; Dennis R. Kelly
Refurbishment of SRB aluminum components by walnut hull blast removal of protective coatings
A test program was conducted to develop, optimize, and scale up an abrasive blasting procedure was developed for refurbishment of specific SRB components: aft skirt, forward skirt, frustrum, and painted piece parts. Test specimens utilizing 2219 T87 aluminum substrate of varying thicknesses were prepared and blasted at progressively increasing pressures with selected abrasives. Specimens were analyzed for material response. The optimum blasting parameters were determined on panel specimens and verified on a large cylindrical integrated test bed.
Colberg, W. R.; Gordon, G. H.; Jackson, C. H.
Dry Flowing Abrasive Decontamination Technique for Pipe Systems with Swirling Air Flow
A dry abrasive decontamination method was developed for removing radioactive corrosion products from surfaces of coolant pipe systems in decommissioning of a nuclear power plant. Erosion behavior of inside surfaces of stainless and carbon steel pipes by a swirling air flow containing alumina or cast-iron grit abrasive was studied. Erosion depths of the test pipes were approximately proportional to an abrasive concentration in air and an exponent of flow rate of airstream. The experimental results indicated that the present method could keep satisfactory erosion ability of abrasives even for a large-size pipe. The present method was successfully applied to {sup 60}Co-contaminated specimens sampled from a pipe of the water cleanup system of the Japan Power Demonstration Reactor.
Kameo, Yutaka; Nakashima, Mikio; Hirabayashi, Takakuni [Japan Atomic Energy Research Institute (Japan)
Abrasive wear in multiphase microstructures
General theories of abrasive wear are reviewed, and wear is related to abrasive size, shape, hardness and degradation tendency. Treatment of matrix effects includes the roles of matrix microhardness, subsurface deformation and retained austenite on abrasion resistance. Discussion of second phase particle effects includes abrasion in carbon steels, and wear in systems containing fine, medium and coarse carbides. Examples are given in which abrasive wear is a function of microstructure and abrasive properties. 52 refs.
Kosel, T.H.; Fiore, N.F.
Influence of Whole Barley and Grit on Live Performance and Health of Turkey Toms1
Live performance to 96 d was compared for 1,584 turkey toms reared on diets containing four levels of whole barley and two levels of insoluble grit (0 or 9 g\\/bird per wk). Nutrient specifications for all diets were similar. The six dietary treatments were 1) 0% whole barley plus grit, 2) Treatment 1 minus grit, 3) grit plus 5% whole
C. D. Bennett; H. L. Classen; K. Schwean; C. Riddell
Single Grit Grinding Simulation by Using Finite Element Analysis
In this research, basic material removal characteristics in a single grit grinding have been investigated by using Finite Element Analysis (FEA). ABAQUS/Standard is used as a computational environment. The influences of both friction and undeformed chip thickness are considered in the analyses of the grit ploughing, stress distribution and total force variation. Remeshing strategy is performed in the simulation to produce very fine meshes in the contact area to mitigate the material distortion due to large plastic deformation. The results show that the increase of undeformed chip thickness and frictional coefficient would increase ploughing action and grinding stress magnitude. Moreover, friction would cause the stress distribution circle on grit inclined backwards. Finally, FEM analysis can be considered as a strong tool for the single grit simulation of grinding process.
�p�z, Tahsin Tecelli; Chen, Xun
Laboratory tests were conducted to determine the fatigue performance of AWJ-machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results not only confirmed the findings of the aluminum dog-bone specimens but also further enhance the fatigue performance. In addition, titanium is known to be notoriously difficult to cut with contact tools while AWJs cut it 34% faster than stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred combination for processing aircraft titanium that is fatigue critical.
The effects of dry-grid blasting of AWJ-machined dog-bone specimens of aircraft aluminum with aluminum oxide abrasives were investigated in terms of enhancement in fatigue performance and mitigating concerns of abrasive contamination. Results obtained from fatigue tests have indicated that the surface roughness, Ra, of AWJ-induced striations is inversely proportional to the fatigue life. The fatigue life of AWJ-machined and baseline
H. T. Liu; Yuri Hovanski; Michael E. Dahl; J. Zeng
The effects of grit supplementation and feed type on steel-shot ingestion in mallards.
Lead poisoning by shot-pellet ingestion is an important cause of death in waterfowl from wetlands that have high densities of lead-shot pellets and low availabilities of grit in their sediments. To evaluate grit supplementation when mixed with baited grain as a method of reducing shot ingestion in waterfowl, 24 mallards (Anas platyrhynchos) were kept in captivity to study the relationship between steel-shot, grit and grain ingestion in four experiments. Steel-shot ingestion was more related to seeking grit than to feeding on grain, and it did not differ between two types of grain offered (rice or sorghum). Grit ingestion increased with grit supplementation and shot ingestion was only slightly reduced. Calcareous grit used in the experiments had a shorter half-life (1.4 days) in the gizzard than values reported for siliceous grit (3.1 days). PMID:10760404
Mateo, R; Guitart, R
Microstructural effects in abrasive wear. Final report
The research program has aimed at establishing quantitative relationships between microstructural variables and abrasion resistance of highly alloyed materials including high Cr-Mo white cast irons and Co-base alloys. Low-stress abrasion resistance has been quantified using a rubber-wheel abrasion test (RWAT) employing dry particles of semi-rounded Ottowa quartz abrasive, crushed quartz abrasive, and crushed Al�O� abrasive. Abrasion under fixed-abrasive conditions has
T. H. Kosel; C. M. Rao; M. T. Fernandes; N. F. Fiore
Valve for abrasive material
A ball valve assembly for controlling the flow of abrasive particulates including an enlarged section at the bore inlet and an enlarged section at the bore outlet. A refractory ceramic annular deflector is positioned in each of the enlarged sections, substantially extending the useful life of the valve.
Gardner, Harold S. (Turtle Creek, PA) [Turtle Creek, PA
Abrasion resistant heat pipe
A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.
Ernst, D.M.
A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.
Ernst, Donald M. (Leola, PA)
Investigation into micro abrasive intermittent jet machining
In the machining of small holes by the conventional micro abrasive jet machining, the colliding abrasives accumulate in the bottom of the hole, preventing the direct impact of successive abrasives onto the workpiece. As a result, the machining efficiency decreases as the machining progresses. This paper introduces a new method of micro abrasive jet machining, called micro abrasive intermittent jet
Lei Zhang; Tsunemoto Kuriyagawa; Yuya Yasutomi; Ji Zhao
Should we be gritting pavements to prevent pedestrian injuries?
Unintentional injuries are an important public health issue, and are a significant burden on health and social services, especially during the winter months. Dr Rob Atenstaedt, Consultant in Public Health Medicine, Public Health Wales & Honorary Senior Lecturer, Bangor University and Professor Michael Rees, University Director of Medical Development & Professor of Cardiovascular Studies, Bangor University look at the importance of pavement gritting in preventing injuries and falls in pedestrians. PMID:23657235
Atenstaedt, Rob; Rees, Michael
29 CFR 1915.134 - Abrasive wheels.
Code of Federal Regulations, 2013 CFR
...2013-07-01 2013-07-01 false Abrasive wheels. 1915.134 Section 1915...and Related Equipment § 1915.134 Abrasive wheels. This section shall apply... (a) Floor stand and bench mounted abrasive wheels used for external...
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false Abrasive wheels. 1915.134 Section 1915...and Related Equipment § 1915.134 Abrasive wheels. This section shall apply... (a) Floor stand and bench mounted abrasive wheels used for external...
...2009-07-01 2009-07-01 false Abrasive wheels. 1915.134 Section 1915...and Related Equipment § 1915.134 Abrasive wheels. This section shall apply... (a) Floor stand and bench mounted abrasive wheels used for external...
Industry and Trade Summary: Abrasives.
The summary covers abrasives and abrasive materials, which are included as parts of chapters 25, 28, 68, 71, and 72 of the Harmonized Tariff Schedules of the United States (HTS), for the years 1989-93. Products contained in the summary include both natura...
V. DeSapio
Why birds eat colourful grit: colour preferences revealed by the colour of gizzard stones.
Colour preferences from sexual or social contexts are assumed to have arisen owing to preferences for specific kinds of food, representing a sensory bias, but once colour preferences have evolved in a sexual context, they may also be expressed during foraging. We tested whether preferences for specific body colours (i.e. plumage and soft parts) were related to colour preferences for grit ingested by birds. Birds eat grit to facilitate break down of food by the gizzard, and this function is independent of the colour of grit, but depends on the physical properties of stones. Bird species were significantly consistent in colour of grit, and grit of different colours varied in prevalence among species, even when analyses were restricted to a sample from a single locality. There were positive correlations between presence of lilac and red grit in the gizzard and presence of sexually dichromatic lilac and red colour on the body. There was a positive correlation between red grit colour and red sexually monochromatic body colour. Bird species with many different sexual colours, but not sexually monochromatic colours on their body had many different colours of grit. Males had more lilac and red grit than females, with this effect differing among species, whereas that was not the case for grit of other colours. These findings are consistent with the sensory bias hypothesis that birds express preferences for grit of specific colours and a high diversity of colours related to sexual colouration of the body, even when the colour of such grit is only visible to the individual at the moment of ingestion. PMID:20050966
M�ller, A P; Erritz�e, J
Blast injury.
The shock wave generated by an explosion ("blast wave") may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude. PMID:6015742
de Candole, C A
Grit, conscientiousness, and the transtheoretical model of change for exercise behavior.
Grit and the Big Five Inventory (BFI) Conscientiousness dimension were examined with respect to the transtheoretical model (TTM) stages of change for exercise behavior. Participants (N = 1171) completed an online survey containing exercise-related TTM staging questions, the Short Grit Scale and BFI Conscientiousness. Ordinal regression analyses showed that grit significantly predicted high intensity and moderate intensity exercise TTM stage while BFI Conscientiousness did not. The results suggest that grit is a potentially important differentiator of TTM stage for moderate and high intensity exercise. PMID:22904153
Reed, Justy; Pritschet, Brian L; Cutton, David M
Cyanoacrylates and corneal abrasion.
Cyanoacrylate-containing adhesives such as Super Glue, Krazy Glue, and a vast array of artificial nail adhesives are monomers which rapidly polymerize and bond in the presence of water or weak bases. Inadvertent contact with skin or tissue can also cause rapid bonding with resultant irritation. To assess the magnitude of problems associated with ocular contamination involving cyanoacrylates, a 12-month prospective study was conducted. 34 cases (21 adult and 13 pediatric) were collected. In all cases, contaminated eyes were thoroughly irrigated with tepid water for 15 minutes. 15 patients (44%) suffered a corneal abrasion, as determined by ophthalmic exam, necessitating treatment with antibiotics, cycloplegics, and patching. Individuals reporting complete resolution were irrigated with 20 minutes of exposure, while patients suffering mechanical injury delayed decontamination for a minimum of 15 minutes. In addition to immediate irrigation of eyes exposed to cyanoacrylates, we recommend an ophthalmologic evaluation to rule out the possibility of mechanical injury. PMID:2810442
Dean, B S; Krenzelok, E P
Investigation into magnetorheological abrasive honing (MRAH)
A scheme to finish external curved surfaces, by imparting rotation while the abrasive-mixed magnetorheological fluid (or abrasive-mixed MR fluid) is pushed up and down, is presented in this paper. Since the relative motions resemble those present in conventional honing, the proposed method is named as �Magnetorheological Abrasive Honing� (MRAH). This paper outlines the design and development of magnetorheological abrasive honing
A. Sadiq; M. S. Shunmugam
Resistance to particle abrasion of selected plastics
Accelerated abrasive wear of plastic parts in a piece of production machinery prompted a laboratory study to find a material with better abrasion resistance. The abrasion occurred in a machine that compacted �sand-like� particles of an inorganic compound. The abrasion resistance of a wide variety of plastics and different durometer polyurethanes (21 materials) was tested with a modification of the
Kenneth G. Budinski
Novel Approach to Abrasion Resistance.
The high abrasion and impact loads characteristic of many technologies require frequent maintenance or special materials. Conventional approaches to protection have used either extremely hard coatings or complaint elastomeric coatings. The former are typi...
W. A. Steele P. B. Mohr H. R. Leider T. B. Hirschfeld
Abrasive wear of cemented carbides
Cemented carbides are used for a wide variety of applications where wear is a problem. Usually the wear of the cemented carbides is a combination of metal-to-metal and abrasion. Wear can occur at room or elevated temperatures. This research summarizes initial research to understand the abrasive wear of various cemented carbides (various grain sizes, carbide types, carbide grain sizes and binder compositions) in terms of absolute material removal rates and material removal mechanisms.
Hawk, Jeffrey A.; Wilson, Rick D.
Laser Ablation Surface Preparation of Carbon Fiber Reinforced Epoxy Composites for Adhesive Bonding.
Surface preparation is widely recognized as a key step to producing robust and predictable bonds in a precise and reproducible manner. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, can lack precision and ...
C. J. Wohl F. L. Palmieri J. W. Connell K. Y. Blohowiak M. A. Belcher
Physics of loose abrasive microgrinding.
This study examined the physics of loose abrasive microgrinding (grinding with micron and submicron sized abrasives). More specifically, it focused on the transition from brittle to ductile mode grinding which occurs in this region of abrasive sizes. Process dependency on slurry chemistry was the primary area of emphasis and was studied for diamond abrasives varying in size from 3.0 to 0.75 microm on both ULE and Zerodur, with emphasis on ULE. Ductile mode grinding was achieved with smaller abrasives, as expected, however two significant discoveries were made. The first observation was that by simply changing slurry chemistry, it was possible to induce the transition from brittle fracture to ductile mode grinding in ULE. This transition point could be intentionally moved about for diamonds 3.0-0.75 microm in diameter. For any given abrasive size within these limits, either brittle fracture or ductile removal may be achieved, depending on the slurry used to suspend the diamonds. Several slurries were studied, including water, a series of homologous n-alcohols, and other solvents chosen for properties varying from molecular size to dielectric constant and zeta potential. The study revealed that this slurry dependency is primarily a Rebinder effect. The second finding was that a tremendous amount of surface stress is introduced in loose abrasive ductile mode grinding. This stress was observed when the Twyman Effect in ULE plates increased by a factor of 4 in the transition from the brittle to the ductile mode. An assessment of the cause of this stress is discussed. PMID:20700273
Golini, D; Jacobs, S D
Characterization of Graphite Coatings Produced by CoBlast� Technology
In this article, the surface characterization of graphite-based coatings deposited on metallic substrates at ambient temperature via a modified micro-blasting process technique named CoBlast� is reported. The coated metals were characterized using scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffractometer, and x-ray photoelectron spectroscopy. Surface roughness and contact angles were also evaluated. The results showed that the coated layer irrespective of the substrate type was hydrophobic and consisted of graphite, the grit material, and surface oxides, while surface roughness values varied from one substrate to the other. Implications of the resulting surface properties in relation to wear and corrosion applications are highlighted.
Oladoye, A. M.; Carton, J. G.; Olabi, A. G.
Conduit Coating Abrasion Testing
During my summer internship at NASA I have been working alongside the team members of the RESTORE project. Engineers working on the RESTORE project are creating �a device that can go into space and service satellites that no longer work due to gas shortage or other technical difficulties. In order to complete the task of refueling the satellite a hose needs to be used and covered with a material that can withstand effects of space. The conduit coating abrasion test will help the researchers figure out what type of thermal coating to use on the hose that will be refueling the satellites. The objective of the project is to determine whether or not the conduit coating will withstand the effects of space. For the RESTORE project I will help with various aspects of the testing that needed to be done in order to determine which type of conduit should be used for refueling the satellite. During my time on the project I will be assisting with wiring a relay board that connected to the test set up by soldering, configuring wires and testing for continuity. Prior to the testing I will work on creating the testing site and help write the procedure for the test. The testing will take place over a span of two weeks and lead to an informative conclusion. Working alongside various RESTORE team members I will assist with the project's documentation and records. All in all, throughout my internship at NASA I hope to learn a number of valuable skills and be a part of a hard working team of engineers.
Sullivan, Mary K.
Effects of different blasting materials on charge generation and decay on titanium surface after sandblasting.
It has been reported that sandblasting titanium with alumina (Al2O3) powder could generate a negative electric charge on titanium surface. This has been proven to promote osteoblast activities and possibly osseointegration. The purpose of this pilot study was to investigate the effects of different blasting materials, in terms of the grit sizes and electro-negativity, on the generation of a negative charge on the titanium surface. The aim was also to make use of these results to deduct the underlying mechanism of charge generation by sandblasting. Together 60 c.p. 2 titanium plates were machine-cut and polished for sandblasting, and divided into 6 groups with 10 plates in each. Every plate in the study groups was sandblasted with one of the following 6 powder materials: 110�m Al2O3 grits, 50�m Al2O3 grits, 150-300�m glass beads, 45-75�m glass beads, 250�m Al powder and 44�m Al powder. The static voltage on the surface of every titanium plate was measured immediately after sandblasting. The static voltages of the titanium plates were recorded and processed using statistical analysis. The results suggested that only sandblasting with 45-75�m glass beads generated a positive charge on titanium, while using all other blasting materials lead to a negative charge. Furthermore, blasting grits of the same powder material but of different sizes might lead to different amount and polarity of the charges. This triboelectric effect is likely to be the main mechanism for charge generation through sandblasting. PMID:24463476
Guo, Cecilia Yan; Hong Tang, Alexander Tin; Hon Tsoi, James Kit; Matinlinna, Jukka Pekka
Abrasion during pyroclastic density currents
During mass movements of any kind, particles interact with other particles. Rounded clasts in deposits from pyroclastic density currents (PDCs) have been observed repeatedly and are attributed to surface rounding (abrasion) or grain-size reduction (disruption) with following abrasion at the newly formed edges during clast collision. Transport-related processes of such kind will influence flow and sedimentation characteristics and grain size distribution in the deposits. Due to their heterogeneous composition in grain size and temperature (as well the velocities and energy involved), simulation of natural volcanic rock mass movements are generally not feasible in the laboratory. Here, rotational movement in a closed container was used as a proxy to shed light on the susceptibility of porous clasts to abrasion. In this study, variously porous clasts of Unzen volcano (Japan) have been investigated ranging in open porosity from 5.7 to 53.5 vol.%. In different experimental runs, the starting grain size was homogeneous (-3.0 and -3.5 Phi, respectively) or heterogeneous (from -3.5 to 1.0 Phi). 40 to 160 g of the dry sample material were subject to rotational movement at ambient temperature in a rotational tumbler at constant speed. Experimental durations were 15, 30, 45, 60, and 120 minutes, respectively. The experimental durations employed are much longer than natural run-out times of volcanic mass movements, in order to help account for their highly energetic nature. Every experiment started with new sample material. The increase in generated fine particles (< 250 ?m) was evaluated as a function of experimental duration and the open porosity of the samples. The degree of abrasion was generally found to be slightly higher with coarser starting material size. The amount of generated particles is positively but non-linearly correlated with increasing porosity and is as high as 6 wt.%. Abrasion is highest for the longest experimental durations but a decreasing rate of efficiency is exhibited. Dense samples are slightly abraded and the increase in generated fine particles remained minor (< 1 wt.%) even in the 120 min experiments. Large phenocrysts were found to have represented zones of higher resistivity to abrasion. It remains speculative, which of the performed experiments is closest to the natural scenario in PDCs. However, the results prove the dependency of abrasion on the physical properties of the sample. Increasing amounts of ash in volcanic currents influence flow and deposition behaviour by affecting effective runout distances and the mobility of the current. Consequently, knowledge of ash generation by abrasion is badly needed for adequate hazard assessment.
Putz, Constanze; Kueppers, Ulrich; Dingwell, Donald B.
Hard Rock Cutting with Abrasion Jet.
The usefulness of high-pressure waterjets in cutting hard materials such as concrete, rock, and minerals was significantly improved by entraining selective abrasives into the waterjet. In fact, good entrainment of abrasives into the waterjet was found to ...
G. G. Yie
Abrasive wear resistance of some commercial abrasion resistant steels evaluated by laboratory test methods
The aim of the present study is to evaluate the abrasive wear resistance of some potential abrasion resistant steels exposed to different types of abrasive wear contact conditions typical of mining and transportation applications. The steels investigated, include a ferritic stainless steel, a medium alloyed ferritic carbon steel and a medium alloyed martensitic carbon steel.The abrasive wear resistance of the
Jos� Rend�n; Mikael Olsson
Effect of fracture toughness on abrasive wear resistance of steels
Various abrasive wear mechanisms were reviewed and an abrasive wear modeling experiment is assessed. Abrasive wear resistance of non-heat treated and heat treated steels has been determined by using a pin-abrasion machine with five abrasive papers, which grinds on a small pin of test materials. The mass loss of test material during abrasive wear was determined gravimetrically. A correlation between
I. Sevim; I. B. Eryurek
Claw Abrasives in Layer Cages - A Review
A review was undertaken to obtain information on the range of claw abrasives which could be used in layer cages to keep claws of hens blunt. In Europe a council directive has been issued which requires that all layer cages be fitted with suitable claw shortening devices. Research in Europe on claw abrasives suggest that abrasives reduce claw length of
P. C. Glatz
Reuse of grits waste for the production of soil--cement bricks.
This investigation focuses on the reuse of grits waste as a raw material for replacing Portland cement by up to 30�wt.% in soil-cement bricks. The grits waste was obtained from a cellulose factory located in south-eastern Brazil. We initially characterized the waste sample with respect to its chemical composition, X-ray diffraction, fineness index, morphology, pozzolanic activity, and pollution potential. Soil-cement bricks were then prepared using the waste material and were tested to determine their technological properties (e.g., water absorption, apparent density, volumetric shrinkage, and compressive strength). Microstructural evolution was accompanied by confocal microscopy. It was found that the grits waste is mainly composed of calcite (CaCO3) particles. Our results indicate that grits waste can be used economically, safely, and sustainably at weight percentages of up to 20% to partially replace Portland cement in soil-cement bricks. PMID:24140481
Siqueira, F B; Holanda, J N F
Brazing diamond grits onto a steel substrate using copper alloys as the filler metals
Surface-set diamond tools were fabricated by an active metal brazing process, using bronze (Cu-8.9Sn) powder and 316L stainless steel powder mixed to various ratios as the braze filler metals. The diamond grits were brazed onto a steel substrate at 1050 �C for 30 min in a dry hydrogen atmosphere. After brazing practice, an intermediate layer rich in chromium formed between the braze filler metal and diamond. A braze filler metal composed of 70 wt % bronze powder and 30 wt % stainless steel powder was found to be optimum in that the diamond grits were strongly impregnated in the filler metal by both mechanical and chemical types of holding. The diamond tools thus fabricated performed better than conventional nickel-plated diamond tools. In service, the braze filler metal wore at almost the same rate as the diamond grits, and no pullout of diamond grits or peeling of the filler metal layer took place.
Chen, S.-M.; Lin, S.-T.
Modern BLAST Programs
The Basic Local Alignment Search Tool (BLAST) is arguably the most widely used program in bioinformatics. By sacrificing sensitivity for speed, it makes sequence comparison practical on huge sequence databases currently available. The original version of BLAST was developed in 1990. Since then it has spawned a variant of specialized programs. This chapter surveys the development of BLAST and BLAST-like programs for homology search, discusses alignment statistics that are used in assessment of reported matches in BLAST, and provides the reader with guidance to select appropriate programs and set proper parameters to match research requirements.
Ma, Jian; Zhang, Louxin
Abrasive swivel assembly and method
An abrasive swivel assembly for providing a rotating, particle-laden fluid stream and, ultimately, a rotating particle-laden fluid jet is disclosed herein. This assembly includes a tubular arrangement for providing a particle-free stream of fluid, means for rotating a section of the tubular arrangement, and means for introducing solid particles into the particle-free fluid stream at a point along the rotating tubular section, whereby to produce a particle-laden fluid stream. This last-mentioned stream can then be used in combination with a cooperating nozzle arrangement for providing a rotating particle-laden fluid jet. In an actual working embodiment, the fluid stream is of sufficiently high pressure so that the abrasive jet can be used as a cutting jet.
Hashish, Mohamed (Kent, WA); Marvin, Mark (Tacoma, WA)
An abrasive swivel assembly for providing a rotating, particle-laden fluid stream and, ultimately, a rotating particle-laden fluid jet is disclosed herein. This assembly includes a tubular arrangement for providing a particle-free stream of fluid, a swivel assembly for rotating a section of the tubular arrangement, and a tubular end section for introducing solid particles into the particle-free fluid stream at a point along the rotating tubular section, whereby to produce a particle-laden fluid stream. This last-mentioned stream can then be used in combination with a cooperating nozzle arrangement for providing a rotating particle-laden fluid jet. In an actual working embodiment, the fluid stream is of sufficiently high pressure so that the abrasive jet can be used as a cutting jet.
Micro abrasive pencils with CVD diamond coating
Abrasive pencils (burs) for grinding can be made by coating cemented carbide bodies with a rough chemical vapour deposition (CVD) diamond layer. These tools have advantages compared to conventional abrasive pencils made by electroplating or sintering of diamond grains. Different CVD diamond abrasive pencils were manufactured with tip diameters ranging from 0.06 to 2.0 mm. A hot-filament CVD reactor was
Jan G�bler; Lothar Sch�fer; Bernd Menze; Hans-Werner Hoffmeister
Abrasive waterjet machining simulation by SPH method
Abrasive waterjet machining (AWJM) is a non-conventional process. The mechanism of material removing in AWJM for ductile materials\\u000a and existing erosion models are reviewed in this paper. To overcome the difficulties of fluid�solid interaction and extra-large\\u000a deformation problem using finite element method (FEM), the SPH-coupled FEM modeling for abrasive waterjet machining simulation\\u000a is presented, in which the abrasive waterjet is
Wang Jianming; Gao Na; Gong Wenjun
Study of the rheological properties and the finishing behavior of abrasive gels in abrasive flow machining
Abrasive flow machining (AFM) is an effective method to finish the smooth surface in the complex holes. Abrasive media are\\u000a key elements which dominate the polished results in AFM. But it is hard to develop the machining model of these abrasive gels\\u000a because of its complicated mechanism. In this research, a non-Newtonian flow is used to set up the abrasive
A. C. Wang; C. H. Liu; K. Z. Liang; S. H. Pai
Blast furnace stove control
This paper outlines the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed. It is then used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The controller also considers maximum and minimum temperature constraints within the stove.
Muske, K.R. [Villanova Univ., PA (United States). Dept. of Chemical Engineering; Hansen, G.A.; Howse, J.W.; Cagliostro, D.J. [Los Alamos National Lab., NM (United States); Chaubal, P.C. [Inland Steel Industries Inc., East Chicago, IN (United States). Research Labs.
Combined study of wear and abrasive fragmentation using Steel Wheel Abrasion Test
Scores of abrasive wear problems particularly those in the harsh environments involve remarkable breakage of the abrasive. One notable case is the ore breakage and the media wear in the comminution devices such as tumbling mills, where the abrasive breakage is indeed the objective of the process. While there are standard test methods for wear or breakage characterization of the
P. Hosseini; P. Radziszewski
Abrasive drill for resilient materials
Resilient materials normally present problem in obtaining accurate and uniform hole size and position. Tool is fabricated from stiff metal rod such as tungsten or carbon steel that has diameter slightly smaller than required hole. Piercing/centering point is ground on one end of rod. Rod is then plasma-sprayed (flame-sprayed) with suitable hard abrasive coating. High-speed, slow-feed operation of tool is necessary for accurate holes, and this can be done with drill press, hard drill, or similar machines.
Koch, A. J.
21 CFR 872.6030 - Oral cavity abrasive polishing agent.
...2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030...Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a...
...2009-04-01 2009-04-01 false Oral cavity abrasive polishing agent. 872.6030...Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a...
21 CFR 872.6010 - Abrasive device and accessories.
...held by a handpiece. The device includes the abrasive disk, guard for an abrasive disk, abrasive point, polishing agent strip, and polishing wheel. (b) Classification. Class I (general controls). The device is exempt from the...
...2013-04-01 false Oral cavity abrasive polishing agent. 872.6030 Section 872... § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or...
...2010-04-01 2010-04-01 false Abrasive device and accessories. 872.6010...Miscellaneous Devices § 872.6010 Abrasive device and accessories. (a) Identification. An abrasive device and accessories is a device...
...2009-04-01 2009-04-01 false Abrasive device and accessories. 872.6010...Miscellaneous Devices § 872.6010 Abrasive device and accessories. (a) Identification. An abrasive device and accessories is a device...
Influence of granite-grit on nutrient digestibility and haematological parameters of broiler chickens fed rice offal based diets.
A total of 270 broiler chickens were used for the study. The birds were fed common diet containing 23% Crude protein and 2864 kcal kg(-1) Metabolizable energy at the starter phase while 20% Crude protein and 2923 kcal kg(-1) Metabolizable energy was fed at the finisher phase. Starter and finisher diets contained 10 and 15% inclusion levels of rice offal respectively. Granite grit was added to the basal diet at 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 g per bird per month thus making a total of six treatments. Each treatment was replicated three times with 15 birds per replicate in a completely randomized design. Packed cell volume and haemoglobin level were not significantly (p>0.05) affected by dietary grit levels while total protein increased across the graded levels of granite grit. Crude protein, crude fibre and nitrogen free extract significantly (p<0.05) improved with increasing grit levels. These parameters improved up to the highest level of grit addition (10.0 g) granite-grit. It was concluded that 10.0 g granite grit per bird per month is beneficial to broiler chickens as it allows for efficient nutrient utilization. Further study to determine the optimum level of granite grit in broiler diet is encouraged since result obtained showed the optimum level was not attained. PMID:24502172
Idachaba, C U; Abeke, F O; Olugbemi, T S; Ademu, L A
Abrasion and impact resistant coatings
The study of the application of free filamentary composites in ''pile''-like structures and linings is aimed at cost effective alternatives to the life limiting abrasive and galling wear experienced in solid member flow systems and system elements. The basic approach is to reduce the intensity of interaction between flowing fluid and container to a level which results in little or no abrasive or fretting wear. In the case of flow borne particulates especially, the objective is to select filament materials and geometries which singly and in composite are sufficiently strong to preclude single particle (event) failure but sufficiently flexible to allow essentially damage-free passage. Early evidence is that this condition is primarily dependent on particle energy and filament strength, although there may also be fatigue, especially acoustic involvement. Our thinking to date has been on wear and acoustic fatigue resistant linings for conduit, flow control, particle control, and separation and drag resistant sealing. Both analytic and test studies have been undertaken. Initial work has been aimed at direct determination of basic characteristics of drag and damage threshold. 3 refs., 13 figs., 1 tab.
Steele, W.A.; Mohr, P.B.; Leider, H.R.
Expanded rock blast modeling capabilities of DMC{_}BLAST, including buffer blasting
A discrete element computer program named DMC{_}BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting. This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in 2-D. DMC{_}BLAST calculations compare favorably with data from actual bench blasts. The blast modeling capabilities of DMC{_}BLAST have been expanded to include
D. S. Preece; J. P. Tidman; S. H. Chung
Blast furnace reactions
Vast a dvances h ave b een m ade in blast-furnace t echnology d uring t he p ast two decades through p lant t rials and plant d evelopments a ssisted by research to provide b etter u nderstanding of physical and chemical w orkings of the blast f urnace. T he f ields of research have i ncluded
E. T. Turkdogan
Fracture process in blasting
In order to clarify the respective roles of stress wave and gas pressure in the fragmentation of an underground blast the fracture process in the zone immediately around the borehole was studied by separating the 2 principal blast forces analytically and experimentally. In model tests the explosion wave was simulated by the pulse generated by an underwater spark discharge, and
H. K. Kutter; C. Fairhurst
Computer cast blast modelling
Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than
S. Chung; M. McGill; D. S. Preece
Lightweight blast shield
A tandem warhead missile arrangement that has a composite material housing structure with a first warhead mounted at one end and a second warhead mounted near another end of the composite structure with a dome shaped composite material blast shield mounted between the warheads to protect the second warhead from the blast of the first warhead.
Mixon, Larry C. (Madison, AL); Snyder, George W. (Huntsville, AL); Hill, Scott D. (Toney, AL); Johnson, Gregory L. (Decatur, AL); Wlodarski, J. Frank (Huntsville, AL); von Spakovsky, Alexis P. (Huntsville, AL); Emerson, John D. (Arab, AL); Cole, James M. (Huntsville, AL); Tipton, John P. (Huntsville, AL)
Blast furnace burden detector
A system for measuring the difference between coke and pellet layers in a blast furnace is described. The measurement is based on a high frequency magnetic proximity principle where coke, a conductor, causes a change in apparent coil resistance. Theoretical and experimental results are presented. The application of the system to No.5 Blast Furnace at Inland Steel (USA) is also
H. Gerber; P. Chaubal
Toxicology of blast overpressure
Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that
Nabil M. Elsayed
Abrasion Property of Epoxidized Natural Rubber
The abrasion resistance of two grades of epoxidized natural rubber (ENR 25 and ENR 50) and one grade of styrene-butadiene rubber (SBR) were studied using an Akron abrasion tester. An accelerated sulfur vulcanization system with 2-mercaptobenzothiazole (MBT) as the accelerator is used throughout the study. Carbon black (N 330), precipitated silica, and calcium carbonate were chosen as the fillers. The
B. T. Poh; Mohd. Jaffri B. Razai
Innovations in Abrasive Products for Precision Grinding
This paper is a review of recent developments in the design and manufacture of precision, fixed-abrasive tools. The role of each component within the �engineered composite� is also discussed, with examples showing how the components have been enhanced to achieve their current high levels of performance. The paper also looks at examples where innovations in the abrasive tool have enabled
J. Webster; M. Tricard
Ultrasonic Abrasive Removal Of EDM Recast
Ultrasonic abrasive process removes layer of recast material generated during electrical-discharge machining (EDM) of damper pocket on turbine blade. Form-fitted tool vibrated ultrasonically in damper pocket from which material removed. Vibrations activate abrasive in pocket. Amount of material removed controlled precisely.
Mandel, Johnny L.; Jacobson, Marlowe S.
Abrasive wear of particle-filled polymers
The abrasive wear rates of quartz and glass particle-reinforced PMMA have been measured as a function of filler volume fraction for silicon carbide, quartz and calcite abrasives. The wear rates were found to exceed those predicted by a simple series model. Abraded surfaces were studied by surface profile measurement and SEM. The excess wear is attributed to rapid wear of
S. V. Prasad; P. D. Calvert
Hardfacing and wear plates battle abrasion
This article examines abrasion-resistant steels and hardfacing as two effective weapons at the disposal of material handlers. It points out that abrasion is probably the single most destructive form of wear in the mixing and processing of coal. Particulate matter such as quartz sand and other minerals including coal curtail in-service life of dragline buckets, chute, crusher rolls, gates and
Cold Spraying Activation Using an Abrasive Admixture
In the present study, on the basis of a two-probability model we theoretically analyze the influence of surface erosion and activation due to abrasive particles impacting on the substrate (coating) surface on the total deposition efficiency of a sprayed mixture of abrasive and metal particles. Relations for the total deposition efficiency derived with regard to the activation effect due to abrasive particles were obtained. In the experiments, the deposition efficiency was measured as a function of the abrasive (SiC) concentration in the initial mixture with copper powder, the size of the abrasive particles, and the working-gas (air) stagnation temperature. Modeling data are compared to the present and previously published experimental data, and a good agreement between the data is shown.
Klinkov, S. V.; Kosarev, V. F.
Cleaning power and abrasivity of European toothpastes.
For 41 toothpastes available to European consumers in 1995, the cleaning efficacy was evaluated in comparison with abrasivity on dentin (RDA value). For cleaning power assessment, a modified pellicle cleaning ratio (PCR) measurement method was developed. The method is characterized by a five-day tea-staining procedure on bovine front teeth slabs on a rotating wheel, standardized brushing of the slabs in a V8 cross-brushing machine, and brightness measurement by a chromametric technique. All tested products were in accordance with the new DIN/ISO standard 11,609 for toothpastes in terms of dentin abrasivity. Not a single product exceeded an RDA value of 200. The majority of toothpastes (80%) had an RDA value below 100. Only three products surpassed the reference in cleaning power. Most products (73%) had a cleaning power (PCR value) between 20 and 80. The correlation between cleaning power and dentin abrasion was low (r = 0.66), which can be explained with the different influence on dentin and stains by factors like abrasive type, particle surface and size, as well as the chemical influence of other toothpaste ingredients. Some major trends could be shown on the basis of abrasive types. The ratio PCR to RDA was rather good in most silica-based toothpastes. A lower ratio was found in some products containing calcium carbonate or aluminum trihydrate as the only abrasive. The addition of other abrasives, such as polishing alumina, showed improved cleaning power. Some active ingredients, especially sequenstrants such as sodium tripolyphosphate or AHBP, also improve the PCR/RDA ratio by stain-dissolving action without being abrasive. The data for some special anti-stain products did not differ significantly from standard products. Compared with data measured in 1988, a general trend toward reduced abrasivity without loss of cleaning efficacy could be noticed on the European toothpaste market. This may be mostly due to the increased use of high-performance abrasives such as hydrated silica. PMID:9470519
W�lknitz, P
System for supplying blasting media to a media blasting system
This patent describes a pressure pot system for supplying blasting media under pressure to a pressurized blasting conduit for feeding blasting media to one or more blasting guns, the system including a media storage means and a first and second pressure chambers with means for pressurizing and exhausting the first and second chambers, the media storage means being stacked above
Van Kuiken; L. L. Jr
Characteristics of single-grit rotating scratch with a conical tool on pure titanium
Single-grit rotating scratch tests have been conducted with a conical diamond tool on pure titanium. The force profiles during the scratch event were captured using high frequency force transducers. The mechanisms of material removal have been characterized by optical and scanning electron microscopes. It was observed that the adhesion between the tool and the deformed material and the hardening properties
Hong Wang; Ghatu Subhash; Abhijit Chandra
Effect of various grit burs on marginal integrity of resin composite restorations.
The purpose of this study was to evaluate the generation of enamel cracks and gaps at the cavosurface margin of resin composite restorations using various burs. Saucer-shaped cavities with a bevel were prepared on mid-coronal buccal or lingual surfaces of extracted human molars using a regular-grit round diamond bur, a fine-grit diamond bur, a superfine-grit diamond bur or a six-bladed tungsten carbide bur with an air turbine handpiece. The enamel margin of the cavity in each group was observed by a light microscope. Cavities were restored with a self-etching adhesive and a light-cured composite resin. After thermocycling, enamel cracks and gaps at the cavosurface margins were observed and scored. Specimens were sectioned longitudinally in two halves, and the resin-cavity interface was observed by means of a light microscope. In cavity preparation, the regular-grid diamond bur and the tungsten carbide bur caused more cracks in the marginal enamel than other groups. From the surface and sectioned surface observation of restored teeth, the superfine-grit diamond bur generated fewer cracks and gaps than the other burs. PMID:15868736
Nishimura, Kozo; Ikeda, Masaomi; Yoshikawa, Takako; Otsuki, Masayuki; Tagami, Junji
In-flight Performance of the Balloon Borne LXeGRIT Compton Telescope
The balloon-borne LXeGRIT is the first prototype of a novel Compton telescope based on a high resolution 3-D imaging time projection chamber (TPC). The ionization detector, triggered by the fast Xe scintillation light, measures the three spatial coordinates and the energy deposited by each gamma-ray interaction in its active volume of 2800 cm3 of pure liquid Xenon. As a calorimeter, LXeGRIT is sensitive in the energy range 0.1 - 10 MeV. For gamma-ray imaging, LXeGRIT relies on events with multiple Compton interactions, after their scattering sequence has been correctly reconstructed. Results from experiments with laboratory sources as well as results from the most recent balloon flight experiment have established the response of the instrument as a Compton imager and spectrometer in one detector. We present these results and summarize the performance of LXeGRIT in flight, with respect to the measurement of the background rate and to the imaging of the Crab Nebula in the 1-3 MeV band.
Aprile, Elena; Curioni, Alessandro; Giboni, Karl-Ludwig; Kobayashi, Masanori; Oberlack, Uwe; Chupp, Edward L.; Dunphy, Philip P.; Ventura, Sandro; Doke, Tadayoshi; Kikuchi, Jun
Initiation of Solid Explosives by Impact and Friction: The Influence of Grit
This paper describes an experimental study of the initiation of solid explosives, and in particular the effect of artifically introducing transient hot spots of known maximum temperature. This was done by adding small foreign particles (or grit) of known melting-point. The minimum transient hot-spot temperature for the initiation of a number of secondary and primary explosives has been determined in
F. P. Bowden; O. A. Gurton
A rare Danian (early Paleocene) Chlamydoselachus (Chondrichthyes: Elasmobranchii) from the Takatika Grit, Chatham Islands, New Zealand
Chlamydoselachus teeth recorded from the Takatika Grit, Chatham Islands, Southwest Pacific, are Danian in age and represent a new species of Chlamydoselachidae and the oldest Cenozoic record in the world, once considered to be Lazarus taxon for the early Paleogene. The new species Chlamydoselachus tatere n. sp. is diagnosed by three prominent upright cusps that display weak ornamentation restricted to
Christopher P. Consoli
New blast weapons.
Over the last decade a large number of weapon systems have appeared that use blast as their primary damage mechanism. This is a notable trend; until recently very few warheads relied on blast as their primary output. Most warheads in service use explosives to drive metal such as fragments and shaped charge jets to engage targets. New technologies are now being integrated into warheads that claim to have enhanced blast performance. Blast weapons could have been designed to fill a gap in capability; they are generally used for the attack of 'soft' targets including personnel, both in the open and within protective structures. With the increased number and range of these weapons, it is likely that UK forces will have to face them in future conflicts. This paper briefly describes fuel-air explosive blast weapons and reviews a range of enhanced blast weapons that have been developed recently. The paper concludes with a brief discussion on the reasons why enhanced blast technologies may be proliferating and how this could affect the Defence Medical Services. PMID:11307681
Dearden, P
Passive blast pressure sensor
A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.
King, Michael J.; Sanchez, Roberto J.; Moss, William C.
Lapping with loose abrasives in lens manufacturing
This study deals with lapping process with loose abrasives in large diameter lens manufacturing. Loose abrasive lapping, is a three-body abrasive process in which a fixed load is applied to a plate that presses a slurry consisting of a coolant and abrasive particles onto the optical surface being manufactured. This process is analyzed by examination of the influence of optical glass material parameters on material removal and surface roughness for lens manufacturing conditions. The model established for this analysis uses the concept of lateral fracture, which is based on removal of optical glass material by rolling abrasive particles. The particles remove glass material by lateral cracking. The concept of lateral fracture by rolling abrasive particles is verified as the lapping model, which was found to give a good description of the experimental results. Removal rates and lapping time values at the conventional removal depth are found and which will allow the automation of lapping process for lens manufacturing. The abrasive mineral Barton Garnet was used in the lapping experiments.
Farsakoglu, Omer F.; Kocabas, Hikmet; Bayar, Mutlu; Zengin, D. M.
The abrasion and impact-abrasion behavior of austempered ductile irons
Austempering of ductile irons has led to a new class of irons, Austempered Ductile Irons (ADIs), with improved mechanical strength and fracture toughness lacking in gray cast irons. Laboratory wear tests have been used to evaluate the abrasive and impact-abrasive wear behavior of a suite of ADIs. The use of high-stress, two-body abrasion, low-stress, three-body abrasion, and impact-abrasion tests provides a clear picture of the abrasive wear behavior of the ADIs and the mechanisms of material removal. When combined with hardness measurements, fracture toughness and a knowledge of the microstructure of the ADIs, the overall performance can be assessed relative to more wear resistant materials such as martensitic steels and high-chromium white cast irons
Hawk, Jeffrey A.; Dogan, Omer N.; Lerner, Y.S. (University of Northern Iowa)
Study the characteristics of magnetic finishing with gel abrasive
Given the flexible polishing effect in magnetic abrasive finishing (MAF), the precise and mirrorlike surface can be obtained during this process. However, the abrasives are easily flown away from the working area regardless of what abrasives are used in MAF; this situation will reduce the polished efficiency and induce the pollution problem in the environment. Besides, the abrasives cannot recycle
A. C. Wang; S. J. Lee
Improvement of work surface finish by magnetic abrasive machining
This paper deals with the experimental investigations conducted with magnetic abrasive powder in Magnetic Abrasive Machining. This experimental study is concerned with the experimental setup, development of equipment and detailed experimental investigations for the improvement of work surface finish by Magnetic Abrasive Machining. Experiments were conducted on heat treated stainless steel (AISI 440C) material with silicon carbide as magnetic abrasive.
P. Jayakumar; N. R. Babu; V. Radhakrishnan
A multi-scale measure of particle abrasivity
In the work presented a new technique of characterising particle abrasivity based on the representation of the particle boundary by triangles at different scales has been developed. Initially, a number of artificial particle boundaries were constructed and analysed showing good correlation with their �intuitive� abrasiveness. Later the abrasivity of four types of typical mineral abrasives was characterised and correlated with
M. G. Hamblin; G. W. Stachowiak
Instantaneous Photographic Observation of Abrasive Water Suspension Jets
Experimental studies are performed in order to clarify the effects of abrasive particle on the structure of the abrasive water suspension jet. Observations of jets are conducted at the injection pressure of 12MPa for seven types of abrasives: two types of steel bead, two types of alumina, two types of glass bead, and one type of plastic shot. The experiments show that the jet structure is greatly affected by the particle type and the concentration of the abrasive. By using smaller abrasive particles, the jet can be made more compact, whereas larger abrasive particles tend to promote jet breakup. These tendencies are noticeable in the case of high-density abrasive.
Shimizu, Seiji; Hiraoka, Yukio; Nishiyama, Takanori
The purpose and objective of this design analysis are to develop controls considered necessary and sufficient to implement the requirements for the controlled drilling and blasting excavation of operations support alcoves and test support alcoves in the Exploratory Studies Facility (ESF). The conclusions reached in this analysis will flow down into a construction specification ensuring controlled drilling and blasting excavation will be performed within the bounds established here.
E.F. fitch
Software Verification with BLAST
Abstract: Introduction. Blast (the Berkeley Lazy Abstraction Software verificationTool) is a verification system for checking safety properties of C programs usingautomatic property-driven construction and model checking of software abstractions. Blast implements an abstract-model check-refine loop to check forreachability of a specified label in the program. The abstract model is built onthe fly using predicate abstraction. This model is then checked
Thomas A. Henzinger; Ranjit Jhala; Rupak Majumdar; Gr�goire Sutre
Adhesion and wear behaviour of NCD coatings on Si3N4 by micro-abrasion tests.
Nanocrystalline diamond (NCD) coatings offer an excellent alternative for tribological applications, preserving most of the intrinsic mechanical properties of polycrystalline CVD diamond and adding to it an extreme surface smoothness. Silicon nitride (Si3N4) ceramics are reported to guarantee high adhesion levels to CVD microcrystalline diamond coatings, but the NCD adhesion to Si3N4 is not yet well established. Micro-abrasion tests are appropriate for evaluating the abrasive wear resistance of a given surface, but they also provide information on thin film/substrate interfacial resistance, i.e., film adhesion. In this study, a comparison is made between the behaviour of NCD films deposited by hot-filament chemical vapour deposition (HFCVD) and microwave plasma assisted chemical vapour deposition (MPCVD) techniques. Silicon nitride (Si3N4) ceramic discs were selected as substrates. The NCD depositions by HFCVD and MPCVD were carried out using H2-CH4 and H2-CH4-N2 gas mixtures, respectively. An adequate set of growth parameters was chosen for each CVD technique, resulting in NCD films having a final thickness of 5 microm. A micro-abrasion tribometer was used, with 3 microm diamond grit as the abrasive slurry element. Experiments were carried out at a constant rotational speed (80 r.p.m.) and by varying the applied load in the range of 0.25-0.75 N. The wear rate for MPCVD NCD (3.7 +/- 0.8 x 10(-5) mm3 N(-1) m(-1)) is compatible with those reported for microcrystalline CVD diamond. The HFCVD films displayed poorer adhesion to the Si3N4 ceramic substrates than the MPCVD ones. However, the HFCVD films show better wear resistance as a result of their higher crystallinity according to the UV Raman data, despite evidencing premature adhesion failure. PMID:19504945
Silva, F G; Neto, M A; Fernandes, A J S; Costa, F M; Oliveira, F J; Silva, R F
Impact-abrasion and abrasion of WC-Co: wear mechanisms in severe environments
Hard and super-hard materials have very good abrasive wear resistance. However, in many severe wear environments that make use of these materials, impact is a significant component of that environment. Consequently, the behavior of many of these hard materials in impact-wear conditions need to be understood with respect to the mechanisms of material removal such small scale fracture and subsequent crack growth in the carbide. This study details the behavior of several ?hard? materials in abrasion and impact-abrasion focusing on the mechanisms of material removal due to impact and abrasion.
Hawk, Jeffrey A.; Wilson, Rick D.; Osara, K. (Outokumpu Research Oy)
Industry Sector Analysis, Canada: Synthetic Crude Abrasives.
The market survey covers the synthetic crude abrasives made of silicon carbide and aluminum oxide grains market in Canada. The analysis contains statistical and narrative information on projected market demand, end-users; receptivity of Canadian consumers...
U. U. Yang
Winter Operations-Abrasives and Salt Brine.
The primary objective of winter maintenance operations is to improve traffic safety and efficiency during winter storm periods. Abrasives and salt brines have been successfully applied to increase traction and prevent snow and ice from bonding to road sur...
G. Pesti Y. Liu
Effect of abrasive particle size on wear resistance in steels
The effects of abrasive particle size on wear resistance have been studied extensively. But, none of these studies is completely satisfactory for finding the relation between the abrasive particle size and wear rate. The abrasive wear resistance of non-heat-treated and heat-treated steels produced at broad range of different temperatures, have been determined by using a pin-abrasion machine having five abrasive
Ibrahim Sevim; I. Barlas Eryurek
Abrasive properties of pseudofused titanium carbide powder
1.A study was made of the abrasive properties of pseudofused titanium carbide. It was established that titanium carbide with 17.4 wt.% or more of combined carbon is superior in abrasive power to white electrocorundum and titanium carbide melted in a Tammann furnace but inferior to titanium carbide produced by synthesis from the elements in plasma and by electric arc melting.2.It
G. V. Samsonov; A. A. Adamovskii; V. S. Polishchuk; N. I. Goncharova
Experimental investigations into abrasive flow machining (AFM)
A new non-traditional finishing process known as abrasive flow machining (AFM) is used to deburr, radius, polish and remove recast layer of components in a wide range of applications. The process is relatively new, although around 2000 machines are in use worldwide. Material is removed from the workpiece by flowing a semisolid visco-elastic\\/visco-plastic abrasive-laden medium across the surface to be
V. K. Jain; S. G. Adsul
Advances in abrasive technology--prophylaxis pastes.
A newly developed prophylaxis paste that contains perlite as an abrasive medium was compared to conventional prophylaxis pastes with regard to relative dentin and enamel abrasion, cleaning ability, and polishing power. Rubber cups and nylon brushes were used as paste carriers. Water, flour of pumice, and a dentin polishing paste served as controls. The Prophylaxis Paste Index was created to assess the clinical potential of the various prophylaxis pastes more accurately. The index was computed for dentin as cleaning ability divided by relative dentin abrasion x surface roughness (in Ra) x 10, and for enamel as cleaning ability divided by relative enamel abrasion x surface abrasion (in Ra). On dentin and enamel, the perlite-based prophylaxis paste consistently yielded low relative dentin and enamel abrasion values, a good cleaning ability, and low surface roughness scores with both rubber cups and nylon brushes. Of all tested prophylaxis pastes, the perlite-based prophylaxis paste excelled in the Prophylaxis Paste Index on dentin and enamel and with both rubber cup and nylon brush applications. Therefore, a perlite-containing prophylaxis paste may have broad professional therapeutic indications and may be used universally as a single paste to clean and polish both dentin and enamel. PMID:11887699
Lutz, Felix; Imfeld, Thomas
Geothermal Energy Market Study on the Atlantic Coastal Plain. GRITS (Version 9): Model Description and User's Guide
The Geothermal Resource Interactive Temporal Simulation (GRITS) model calculates the cost and revenue streams for the lifetime of a project that utilizes low to moderate temperature geothermal resources. With these estimates, the net present value of the project is determined. The GRITS model allows preliminary economic evaluations of direct-use applications of geothermal energy under a wide range of resource, demand, and financial conditions, some of which change over the lifetime of the project.
Kroll, Peter; Kane, Sally Minch [eds.
Effects of grit roughness and pitch oscillations on the S809 airfoil
An S809 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU\\/AARL) 3�5 subsonic wind tunnel (3�5) under steady flow and stationary model conditions, and also with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was developed to simulate leading edge
R. F. Ramsay; M. J. Hoffman; G. M. Gregorek
Effects of grit roughness and pitch oscillations on the LS(1)-0421MOD airfoil
An LS(1)-0421 MOD airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU\\/AARL) 3�5 subsonic wind tunnel (3�5) under steady flow and stationary model conditions, and also with the model undergoing pitch oscillations. In order to study the possible extent of performance loss due to surface roughness, a leading edge grit roughness (LEGR) pattern was
R. L. Reuss; M. J. HOffman; G. M. Gregorek
On the background rate in the LXeGRIT Instrument during the 2000 Balloon Flight
LXeGRIT is the first prototype of a novel Compton telescope for MeV gamma-ray astrophysics based on a Liquid Xenon Time Projection Chamber (LXeTPC), sensitive in the energy band of 0.15-10 MeV. In this homogeneous, 3D position sensitive detector, gamma-rays with at least two interactions in the sensitive volume of 2800 cm3, are imaged as in a standard Compton telescope. gamma-rays
Alessandro Curioni; Elena Aprile; Karl-Ludwig Giboni; Masanori Kobayashi; Uwe G. Oberlack; Edward L. Chupp; Philip P. Dunphy; Tadayoshi Doke; Jun Kikuchi; Sandro Ventura
Sol�gel alumina environmental barrier coatings for SiC grit
SiO2 surface film is insufficient to protect SiC from the oxidation at widely varying partial pressures of oxygen, in particular in the presence of water vapor (e.g. in gas turbines) and also in other environments, e.g. during brazing for hard �tipping� of turbine blades. This work demonstrates that sol�gel alumina, coated on ?0.5mm coarse SiC grit, may form an acceptable,
H. Kim; M. Chen; Q. Yang; T. Troczynski
Secondary Waves from Nozzle Blast.
Blast signatures at the gunner's position produced by recoilless rifles and rocket launchers often exhibit a strong secondary wave following chamber blowdown. To identify its source a series of experiments was performed using a helium-driven blast simulat...
G. C. Carofano
Blasting: Another environmental woe
The much increased use of explosives to move and extract rock masses in construction and mining over the past two decades has resulted in a plethora of complaints from the general public in areas of close proximity to public facilities, communication, and transportation systems. Air blasts and ground vibrations caused by explosive detonation can have desultory and damaging effects to public and private property, impose adverse effects on underground mining operations, and change the course of flow or effect the availability of surface and groundwater. Attempts to prevent damage and alleviate problems from blasting have been initiated by the federal and state governments by the promulgation of rules and regulations to prevent against vagrant and negligent blasting procedures. The Office of Surface Mining, Reclamation and Enforcement (OSMRE) provided regulations in the Federal Register on March 8, 1983, with particular reference to surface mining practices. Most of the states have adopted the OSMRE guidelines to enforce these rules and regulations.
Simpson, Thomas A.
Abrasive machining of porcelain and zirconia with a dental handpiece
The machining characteristics and material removal mechanisms of two dental ceramics�feldspathic porcelain and yttria-stabilized tetragonal zirconia�were investigated using a dental handpiece and diamond burs with different grit sizes. The material removal rates were measured as a function of total machining time using a constant load of 2N on the bur, consistent with clinical cutting conditions. As the diamond grit size
L. Yin; S. Jahanmir; L. K. Ives
Facile fabrication of superhydrophobic surface with excellent mechanical abrasion and corrosion resistance on copper substrate by a novel method.
A novel method for controllable fabrication of a superhydrophobic surface with a water contact angle of 162 � 1� and a sliding angle of 3 � 0.5� on copper substrate is reported in this Research Article. The facile and low-cost fabrication process is composed from the electrodeposition in traditional Watts bath and the heat-treatment in the presence of (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane (AC-FAS). The superhydrophobicity of the fabricated surface results from its pine-cone-like hierarchical micro-nanostructure and the assembly of low-surface-energy fluorinated components on it. The superhydrophobic surface exhibits high microhardness and excellent mechanical abrasion resistance because it maintains superhydrophobicity after mechanical abrasion against 800 grit SiC sandpaper for 1.0 m at the applied pressure of 4.80 kPa. Moreover, the superhydrophobic surface has good chemical stability in both acidic and alkaline environments. The potentiodynamic polarization and electrochemical impedance spectroscopy test shows that the as-prepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Cu substrate. In addition, the as-prepared superhydrophobic surface has self-cleaning ability. It is believed that the facile and low-cost method offer an effective strategy and promising industrial applications for fabricating superhydrophobic surfaces on various metallic materials. PMID:24796223
Su, Fenghua; Yao, Kai
This article examines abrasion-resistant steels and hardfacing as two effective weapons at the disposal of material handlers. It points out that abrasion is probably the single most destructive form of wear in the mixing and processing of coal. Particulate matter such as quartz sand and other minerals including coal curtail in-service life of dragline buckets, chute, crusher rolls, gates and valves, exhauster fan blades, target plates, truck beds, hoppers, vibrating pans, grinding mills, piping elbows, etc. The advantages of abrasion-resistant steels and hardfacing can be obtained in the form of a composite wear plate-hardfacing on a carbon steel backup plate. It concludes that the composite wear plate represents a major innovation since its advantages include ease of handling, low cost and easy installation, minimum on-site welding time and versatility. Its use is limited only to the consumer's creativity in application.
Miller, R.F.
Abrasion resistant valves cut platform maintenance cost
Shell Exploration and Production, operator of Brent field in the UK North Sea, turned to Anglo-US valve maker Serck Audco Valves for help in solving persistent valve maintenance problems. Brent Charlie platform was selected as a test site for the supplier`s new line of abrasion-resistant valves. The most common failure cause is abrasion by solids in the line fluid, particularly sand, which damages even stainless steel and Duplex valve seats, creating leak paths which prevent valve sealing. Serck Audco manufacturers the Super-H all-metal pressure-balanced plug valve, which has proved particularly resistant to erosion in some of the world`s harshest operating environments. The paper describes the valve`s extra abrasion resistance and the Brent Charlie test.
Property maps for abrasion resistance of materials.
Using mechanics models of contacting surfaces under both normal and tangential loads, a mechanistic framework has been developed for assessing material resistance to initiation of abrasive damage. Solutions are presented for the critical loads to initiate yielding and cracking at blunt contacts, as well as those to attain a prescribed plastic penetration depth and cause cracking from within the plastic zone at sharp contacts. Material property groups that characterize abrasion resistance emerge from the models. Guided by these groups, illustrative property maps are constructed and used to make comparative assessments of a wide range of engineering materials. PMID:18836523
Zok, F W; Miserez, A
Property maps for abrasion resistance of materials
Using mechanics models of contacting surfaces under both normal and tangential loads, a mechanistic framework has been developed for assessing material resistance to initiation of abrasive damage. Solutions are presented for the critical loads to initiate yielding and cracking at blunt contacts, as well as those to attain a prescribed plastic penetration depth and cause cracking from within the plastic zone at sharp contacts. Material property groups that characterize abrasion resistance emerge from the models. Guided by these groups, illustrative property maps are constructed and used to make comparative assessments of a wide range of engineering materials.
Zok, F.W.; Miserez, A.
29 CFR 1926.303 - Abrasive wheels and tools.
...guard may be omitted; and (ii) The spindle end, nut, and outer flange may be exposed on machines designed as portable saws. (c) Use of abrasive wheels. (1) Floor stand and bench mounted abrasive wheels, used for external grinding,...
Code of Federal Regulations, 2011 CFR
...contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment (prophylaxis cup). (b) Classification. Class I (general controls)....
Code of Federal Regulations, 2012 CFR
Anti-Abrasion Protection with Highly Organized Materials.
Abrasion and impact resistance are a prime requirement for many materials applications. To best protect plastic or metal-based composites from abrasion and impact, a surface coating that is simultaneously very hard and highly yielding is necessary. Both t...
W. A. Steele, H. R. Leider, P. B. Mohr
An investigation of the abrasive wear behavior of ductile cast iron
The abrasive wear behavior of ductile cast iron with four different matrix microstructures was determined by the pin-on-disc abrasion test, the three-body abrasion test and the impact three-body abrasion test. The results indicate that the abrasive wear resistance of ductile cast iron tested in pin-on-disc abrasion and three-body abrasion is approximately linearly proportional to its hardness, so that the abrasive
Zhen-Lin Lu; Yong-Xin Zhou; Qi-Chang Rao; Zhi-Hao Jin
Tribotechnical Characteristics of Ferroabrasive Powders in Magnetic-Abrasion Machining
How the frictional force between magnetic-abrasive powders and a Ti alloy surface varies during magnetic-abrasive machining in relation to the technological parameters has been investigated. The specific behavior of the magnetic-abrasive tool in the course of magnetic-abrasive machining has been found to depend on the variation of its mobility as a function of the size and shape the powders, the
Viktor S. Maiboroda; E. A. Khomenko
The Effects of Abrasives on Electrical Submersible Pumps
The electrical submersible pump (ESP) is a high-speed rotating device. Its operational life in oil wells can depend on the type and quantities of abrasives present in the produced fluid. This paper reports on a set of experiments performed in a specialized abrasive test loop. In the test, the size and quantity of abrasives were varied along with flow rate
Brown Wilson
Magnetic abrasive finishing (MAF) of alloy steel workpiece with unbounded magnetic abrasive particles (UMAPs) indicates that the surface finish in the range of nanometer can be achieved. Important controllable four process parameters have been identified which are as current to the electromagnet, machining gap, abrasive size (mesh number), and number of cycles. Experiments have been planned using design of experiments
Dhirendra K. Singh; V. K. Jain; V. Raghuram
Modeling and simulation of magnetic abrasive finishing process
Magnetic abrasive finishing (MAF) is one of the advanced finishing processes, which produces a high level of surface quality and is primarily controlled by a magnetic field. In MAF, the workpiece is kept between the two poles of a magnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles. A magnetic abrasive flexible brush
S. C. Jayswal; V. K. Jain; P. M. Dixit
Magnetic field assisted abrasive based micro-\\/nano-finishing
Micro-\\/nano-machining (abbreviated as MNM) processes are classified mainly in two classes: traditional and advanced. Majority of the traditional MNM processes are embedded abrasive or fixed geometry cutting tool type processes. Conversely, majority of the advanced MNM processes are loose flowing abrasive based processes in which abrasive orientation and its geometry at the time of interaction with the workpiece is not
V. K. Jain
The surface finishing techniques can be divided into two categories: traditional and advanced. To overcome some of the problems of traditional finishing techniques, hybridized processes have been evolved by the researchers. Some of the advanced finishing processes that have been reviewed are abrasive flow machining (AFM), magnetorheological finishing (MRF), magnetorheological abrasive flow finishing (MRAFF), magnetic abrasive finishing (MAF), chemo mechanical
Analysis of abrasive wear performance of arc welded hard layers
The influence of welded layers composition on the abrasive wear mechanism of friction couples �hard layer-steel� is analyzed. Strength, surface morphology, chemical and structural composition, abrasive wear resistance of welded layers are investigated. When cutting low carbon and chromium content layers with abrasive particles, the wear predominates there as it does under plastic deformation, while in refractory metal layers brittle
V. Jankauskas; R. Kreivaitis; D. Mil?ius; A. Baltu�nikas
Developing the polymer abrasive gels in AFM processs
Abrasive flow machining (AFM) has excellent polishing effect in complex holes cut by wire electrical discharge machining (WEDM). The recast layers produced by WEDM can be removed when the abrasive media passes through the complex hole. Therefore, the media are the key elements that dominate the polishing behavior in AFM. However, commercial abrasive media are very expensive, and not every
A. C. Wang; S. H. Weng
Role of indentation fracture in free abrasive machining of ceramics
Free abrasive machining (FAM) is widely used for stock removal and surface finishing of ceramics. In FAM, material removal results from mechanical action between the abrasive slurry, which is trapped between the workpiece and a rotating lapping block, and the workpiece. Microscopic observations of the machined surface show that lateral cracking due to indentation by the abrasive particles contributes substantially
R. Chauhan; Y. Ahn; S. Chandrasekar; T. N. Farris
The study of polishing and equipment of abrasive flow
Abrasive flow processing is a new kind of surface polishing technology which is widely used for processing complex cavity parts. This paper will systematically illustrate an outline about abrasive flow technology. In addition, it also dedicated to introduce the principle of processing as well as the development & application of abrasive flow. Furthermore, based on the study of Ultra-Precision polishing
Lifeng Yang; Lei Zhao
Hard coatings, such as boron carbide (B4C), can quickly polish the surface of the mating material during sliding contact. The abrasiveness of such coatings directly relates to their ability to polish and sharply decreases as sliding progresses. The abrasiveness also strongly depends upon the sharpness of the individual coating asperities. Various parameters influence the rate at which the abrasiveness decreases
Matthew Siniawski; Stephen J. Harris
...2010-07-01 2010-07-01 false Abrasive wheels and tools. 1926.303 Section...Tools-Hand and Power § 1926.303 Abrasive wheels and tools. (a) Power. ...for the Use, Care and Protection of Abrasive Wheels, and paragraph (d) of...
...2009-07-01 2009-07-01 false Abrasive wheels and tools. 1926.303 Section...Tools-Hand and Power § 1926.303 Abrasive wheels and tools. (a) Power. ...for the Use, Care and Protection of Abrasive Wheels, and paragraph (d) of...
Development of abrasive cut-off wheel having side grooves
The abrasive cut-off wheel fails prematurely during the routine sectioning of workpiece, which may cause injury to the operator. One of the major reasons of premature failure is the improper mixing of the abrasive mixture. In order to provide strength to the wheel, it was reinforced by woven roving type glass fiber and the abrasive mixture was ball milled. Cutting
P. Sahu; R. Sagar
A discrete element computer program named DMC{_}BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting. This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in 2-D. DMC{_}BLAST calculations compare favorably with data from actual bench blasts. The blast modeling capabilities of DMC{_}BLAST have been expanded to include independently dipping geologic layers, top surface, bottom surface and pit floor. The pit can also now be defined using coordinates based on the toe of the bench. A method for modeling decked explosives has been developed which allows accurate treatment of the inert materials (stemming) in the explosive column and approximate treatment of different explosives in the same blasthole. A DMC{_}BLAST user can specify decking through a specific geologic layer with either inert material or a different explosive. Another new feature of DMC{_}BLAST is specification of an uplift angle which is the angle between the normal to the blasthole and a vector defining the direction of explosive loading on particles adjacent to the blasthole. A buffer (choke) blast capability has been added for situations where previously blasted material is adjacent to the free face of the bench preventing any significant lateral motion during the blast.
Preece, D.S. [Sandia National Labs., Albuquerque, NM (United States); Tidman, J.P.; Chung, S.H. [ICI Explosives (Canada)
Evaluation and Treatment of Perioperative Corneal Abrasions
Purpose. To evaluate perioperative risk factors for corneal abrasion (CA) and to determine current care for perioperative CA in a tertiary care setting. Methods. Hospital-based, cross-sectional study. In Operating Room and Post-Anesthesia Care Units patients, a comparison of cases and controls was evaluated to elucidate risk factors, time to treatment, and most common treatments prescribed for corneal abrasions. Results. 86 cases of corneal abrasion and 89 controls were identified from the 78,542 surgical procedures performed over 2 years. Statistically significant risk factors were age (P = 0.0037), general anesthesia (P < 0.001), greater average estimated blood loss (P < 0.001), eyes taped during surgery (P < 0.001), prone position (P < 0.001), trendelenburg position (P < 0.001), and supplemental oxygen en route to and in the Post-Anesthesia Care Units (P < 0.001). Average time to complaint was 129 minutes. 94% of cases had an inpatient ophthalmology consult, with an average time to consult of 164 minutes. The most common treatment was artificial tears alone (40%), followed by combination treatment of antibiotic ointment and artificial tears (35.3%). Conclusions. Trendelenburg positioning is a novel risk factor for CA. Diagnosis and treatment of perioperative corneal abrasions by an ophthalmologist typically require three hours in the tertiary care setting.
Segal, Kira L.; Fleischut, Peter M.; Kim, Charles; Levine, Ben; Faggiani, Susan L.; Banerjee, Samprit; Gadalla, Farida; Lelli, Gary J.
Rock Abrasion Tool: Mars Exploration Rover mission
The Rock Abrasion Tool (RAT) is an integral part of the Athena Science payload. Serving primarily as the geologist's rock hammer, the RAT will expose fresh surfaces of Martian rocks to other instruments on the payload. The RAT also brushes dust and debris from an excavated hole or unaltered rocks. To accomplish these tasks autonomously, the RAT, a sophisticated 3-axis
S. P. Gorevan; T. Myrick; K. Davis; J. J. Chau; P. Bartlett; S. Mukherjee; R. Anderson; S. W. Squyres; R. E. Arvidson; M. B. Madsen; P. Bertelsen; W. Goetz; C. S. Binau; L. Richter
Special features of the magnetic abrasive machining
It is shown, using electron microscopy, magnetic and friction methods, that a mixture of magnetic ?-Fe2O3 and abrasive powders, properly processed, can be used as a material for magnetoabrasive machining and polishing of variously\\u000a shaped components.
K. A. Gogaev; V. V. Nepomnyashchii; T. V. Mosina; I. P. Neshpor; M. Leonowicz
Machining time estimation for magnetic abrasive processes
Here we present the magnetic abrasive process which is used to finish and size those workpieces that have been produced using standard machine tools. The process is proved to be very effective in achieving the desired finish size and roundness of the workpieces. We develop an empirical expression to estimate the machining time to produce a workpiece with specified roundness.
Development of magneto abrasive flow machining process
Abrasive flow machining (AFM) is a relatively new process among non-conventional machining processes. Low material removal rate happens to be one serious limitation of almost all such processes. Limited efforts have hitherto been directed towards improving the efficiency of these processes so as to achieve higher material removal rates by applying different techniques. This paper discusses the possible improvement in
Sehijpal Singh; H. S. Shan
The objective of this work is to develop a finite element method (FEM) based mathematical model to simulate the hybrid machining process of grinding and electric discharge machining (EDM), named as Electro-discharge abrasive grinding (EDAG), for temperature distribution in the workpiece. Two different finite element codes have been developed to calculate the temperature distribution due to grinding heat source and
Vinod Yadava; Vijay K. Jain; Prakash M. Dixit
Technological Advances in Fine Abrasive Processes
Fine abrasives, be they loose or fixed, are invariably used in the production of components of the highest quality in terms of form and finish accuracy, and surface integrity. While optical, mechanical, and electronic applications of advanced ceramics, glasses, and semiconductors may require high form and finish accuracies (e.g., roughnesses in the angstrom range), the depth and nature of the
R. Komanduri; D. A. Lucca; Y. Tani
PC Controlled Toothbrush\\/Dentifrice Abrasion Machine
A toothbrush\\/dentifrice abrasion machine was developed to use in dental research laboratory. The mechanism was designed as a hexagonal block driven by two stepping motors which move the mechanism in four directions. In order to control the stepping motors speed, position and direction commands or signals were generated by a software written in C Programming Language and then these commands
G�ng�r Bal; Sadullah ��ta?li; Erdal Bekiroglu
Gungor Bal; Sadullah Uctasli; Erdal Bekiroglu
Neural Network Modeling of Abrasive Flow Machining
This paper discusses the preliminary development of a neural network-based process monitor and off-line controller for abrasive flow machining of automotive engine intake manifolds. The process is only observable indirectly, yet the time at which machining achieves the specified air flow rate must be estimated accurately. A neural network model is used to estimate when the process has achieved air
Alice E. Smith; William S. Slaughter
Cleaning Power and Abrasivity of European Toothpastes
For 41 toothpastes available to European consumers in 1995, the cleaning efficacy was evaluated in comparison with abrasivity on dentin (RDA value). For cleaning power assessment, a modified pellicle cleaning ratio (PCR) measurement method was developed. The method is characterized by a five-day tea-staining procedure on bovine front teeth slabs on a rotating wheel, standardized brushing of the slabs in
P. Wiilknitz
A universal wear law for abrasion
Finding a wear law that is valid over a wide range of conditions and materials would have enormous practical value. The authors have previously discovered a simple relationship describing the evolution of the abrasive wear rate of steel sliding against boron carbide-coated coupons, and have developed a model accounting for its kinetics. The authors show here that this wear equation
Matthew T. Siniawski; Stephen J. Harris; Qian Wang
Abrasion and impact resistant coatings. Quarterly report
We have proven that a layer of reinforcing filaments emerging out of the surface of a composite provides it with substantial protection from abrasion and impact. We have determined the geometrical constraints on fiber diameter, length, root depths, orientation, and packing density required for this protection. Substantial performance has been demonstrated for even incompletely optimized systems. We are in the
Micro-abrasion�corrosion of cast CoCrMo�Effects of micron and sub-micron sized abrasives
The abrasion damage on retrieved CoCrMo based hip joints is reported to be influenced by the entrainment of micron and sub-micron sized debris\\/hard particles. This paper represents the first attempt to look into the effects of relatively soft abrasives with micron and sub-micron dimensions on the abrasion mechanisms and the abrasion�corrosion performance of the cast CoCrMo in simulated hip joint
D. Sun; J. A. Wharton; R. J. K. Wood
Abrasive wear properties of tool steel matrix composites in rubber wheel abrasion test and laboratory cone crusher experiments
Abrasive wear is the most common type of wear phenomenon in mineral crushing industry. Tool steel matrix-based composites are an attractive choice to combat wear in those conditions because of their excellent abrasion resistance. One purpose of this study is to evaluate the abrasion resistance of such composites having different microstructures. Another purpose is to find out whether the simple
Sanna Ala-Kleme; P�ivi Kivikyt�-Reponen; Jari Liimatainen; Jussi Hellman; Simo-Pekka Hannula
The friction and wear of metals and binary alloys in contact with an abrasive grit of single-crystal silicon carbide
Sliding friction experiments were conducted with various metals and iron-base binary alloys (alloying elements Ti, Cr, Mn, Ni, Rh and W) in contact with single crystal silicon carbide riders. Results indicate that the friction force in the plowing of metal and the groove height (corresponding to the wear volume of the groove) decrease linearly as the shear strength of the bulk metal increases. The coefficient of friction and groove height generally decrease, and the contact pressure increases with an increase in solute content of binary alloys. There appears to be very good correlation of the solute to iron atomic ratio with the decreasing rate of change of coefficient of friction, the decreasing rate of change of groove height and the increasing rate of change of contact pressure with increasing solute content. These rates of change increase as the solute to iron atomic radius ratio increases or decreases from unity.
Sliding friction experiments were conducted with various metals and iron-base binary alloys (alloying elements Ti, Cr, Mn, Ni, Rh, and W) in contact with single-crystal silicon carbide riders. Results indicate that the coefficient of friction and groove height (corresponding to the wear volume) decrease linearly as the shear strength of the bulk metal increases. The coefficient of friction and groove height generally decrease with an increase in solute content of binary alloys. A separate correlation exists between the solute to iron atomic radius ratio and the decreasing rates of change of coefficient of friction and groove height with increasing solute content. These rates of change are minimum at a solute to iron radius ratio of unity. They increase as the atomic ratio increases or decreases linearly from unity. The correlations indicate that atomic size is an important parameter in controlling friction and wear of alloys.
Friction and wear of metals with a single-crystal abrasive grit of silicon carbide: Effect of shear strength of metal
Sliding friction experiments were conducted with spherical, single-crystal silicon carbide riders in contact with various metals and with metal riders in contact with silicon carbide flats. Results indicate that: (1) the friction force in the plowing of metal and (2) the groove height (corresponding to the volume of the groove) are related to the shear strength of the metal. That is, they decrease linearly as the shear strength of the bulk metal increases. Grooves are formed in metals primarily from plastic deformation, with occasional metal removal. The relation between the groove width D and the load W can be expressed by W = kD, superscript n which satisfies Meyer's law.
Performance of blasting caps
Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.
Bement, Laurence J. (inventor); Schimmel, Morry L. (inventor); Perry, Ronnie B. (inventor)
Abrasion-Resistant Technology and its Prospect for CFB Boilers
In recent years, CFB boilers (CFBB) have been widely used in the commercial power plants due to its environmental benefits, high combustion efficiency, wide coal flexibility, and some other advantages. At the same time, the abrasion problem, the greatest weakness of this kind of boiler, has been gradually exposed in its application process. The abrasion, particularly on key parts such as the heating surface of water-cooled wall, furnace corners, separator entrance, seriously restricts the long-period operation ability of the CFBB. This article discusses current development status for various abrasion resistant refractory materials used in a CFBB. Some comments are provided for developing new high-performance abrasion resistant refractory materials and rapid-repaired materials according to the abrasion principle and the abrasion on different parts, as well as the economical and environmental requirements for the material. The abrasion solution and operation period of CFBB can be better improved given realization.
Zheng, H.; Li, Y. J.; Wang, L. J.; Liu, S. H.; Dou, Q. R.
The effect of bleaching on toothbrush abrasion of resin composites
Aim: This experimental study was designed to focus on the effects of bleaching on toothbrush abrasion in three types of composites with different filler size. Materials and Methods: Forty eight disks were prepared from three types of composite and divided into 6 groups. In the first three groups the abrasion test was done. The remaining groups were bleached and the abrasion test was performed. The weight of the samples before and after abrasion was measured. Statistical analysis was done with one-way ANOVA and Duncan test. Results: There was a significant difference in abrasion of composites with different filler size (P < 0.05). The most amount of abrasion was observed in Z100 after being bleached. An increase in abrasion was noticed in all three types of tested composite after bleaching. Conclusion: According to the findings, it is suggested to use a nano filled resin composite for restoration if the bleaching treatment is required.
Hajizadeh, Hila; Ameri, Hamideh; Eslami, Samaneh; Mirzaeepoor, Behnam
Micro Fluidic Channel Machining on Fused Silica Glass Using Powder Blasting
In this study, micro fluid channels are machined on fused silica glass via powder blasting, a mechanical etching process, and the machining characteristics of the channels are experimentally evaluated. In the process, material removal is performed by the collision of micro abrasives injected by highly compressed air on to the target surface. This approach can be characterized as an integration of brittle mode machining based on micro crack propagation. Fused silica glass, a high purity synthetic amorphous silicon dioxide, is selected as a workpiece material. It has a very low thermal expansion coefficient and excellent optical qualities and exceptional transmittance over a wide spectral range, especially in the ultraviolet range. The powder blasting process parameters affecting the machined results are injection pressure, abrasive particle size and density, stand-off distance, number of nozzle scanning, and shape/size of the required patterns. In this study, the influence of the number of nozzle scanning, abrasive particle size, and pattern size on the formation of micro channels is investigated. Machined shapes and surface roughness are measured using a 3-dimensional vision profiler and the results are discussed.
Jang, Ho-Su; Cho, Myeong-Woo; Park, Dong-Sam
A novel approach to abrasion resistance
The high abrasion and impact loads characteristic of many technologies require frequent maintenance or special materials. Conventional approaches to protection have used either extremely hard coatings or complaint elastomeric coatings. The former are typically ceramic or ceramic-like surfaces produced by direct deposition or by in situ formation by oxidation, carburization or nitriding. Ceramic coatings are very good against abrasion, but are vulnerable to impact damage. Elastomeric coatings have excellent impact resistance and are capable of withstanding deformation; however, they are limited in thermal range and chemical resistance. It is possible to combine the desirable properties of both types by using ''hair,'' a structure in which an extremely hard material can be simultaneously elastic and compliant by virture of a very high L/D ratio. We have demonstrated the good performance of carbon fiber ''hair'' in resisting damage from impacting particles and have identified a probable failure mechanism. 7 refs., 6 figs., 1 tab.
Steele, W.A.; Mohr, P.B.; Leider, H.R.; Hirschfeld, T.B.
Cryogenically assisted abrasive jet micromachining of polymers
The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN2) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN2 also was found to reduce particle embedding.
Getu, H.; Spelt, J. K.; Papini, M.
Scratching of polymers�Modeling abrasive wear
This paper aims to model abrasive wear for polymers using single-track and intersecting scratching techniques. Scratch and pin-on-disc wear tests were conducted on five different commercial polymers. Wear debris generated by multiple-pass single-track and intersecting scratching tests were compared and correlated with the specific wear rates of the same polymers in a pin-on-disk test using ground steel surface (Ra=1.34?m) as
Sujeet K. Sinha; W. L. M. Chong; Seh-Chun Lim
Abrasive wear performance of various polyamides
Polyamides (PAs) form a major class of tribo-polymers used in almost all types of wear situations. They excel most of the engineering polymers especially in the case of abrasive wear performance. Since methylene (?CH2?) to amide (?CONH?) group ratio in PAs control the physical and mechanical properties, it was thought interesting to examine its influence on tribo-performance also. Hence, two
J. John Rajesh; J Bijwe
Abrasive wear of titanium nitride coatings
Titanium nitride thin films, deposited by plasma vapor deposition (PVD) or chemical vapor deposition (CVD), are commonly used on metal cutting tools. The TiN coating increases cutting tool-life and extends the tool operating range. This paper examines the behavior of PVD TiN on high-speed steel (HSS) substrates under low stress abrasion. High-speed steel bars were coated with TiN by a
M. Scholl
Loose abrasive slurries for optical glass lapping
Loose abrasive lapping is widely used to prepare optical glass before its final polishing. We carried out a comparison of 20 different slurries from four different vendors. Slurry particle sizes and morphologies were measured. Fused silica samples were lapped with these different slurries on a single side polishing machine and characterized in terms of surface roughness and depth of subsurface damage (SSD). Effects of load, rotation speed, and slurry concentration during lapping on roughness, material removal rate, and SSD were investigated.
Neauport, Jerome; Destribats, Julie; Maunier, Cedric; Ambard, Chrystel; Cormont, Philippe; Pintault, B.; Rondeau, Olivier
Abrasion testing of submarine pipe coatings
To evaluate the coating damage caused by pulling pipelines over coral and sandstone seabeds, abrasion field tests were conducted on various coating materials - concrete, coal-tar enamel, extruded polyethylene, coal-tar epoxy paint, alumina-filled epoxy paint, and sand-filled epoxy coating - as well as on two types of joint coverings, the heat-shrinkable plastic sleeve and laminated pipe tape. The thin-film epoxy
Design of an impact abrasion testing machine
By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of
D. Zhang; P. R. Beeley; A. J. Baker
Impeller wear impact-abrasive wear test
In order to more accurately simulate wear behavior that occurs in the field (i.e., impact coupled with abrasion), an impeller-in-drum wear test has been developed. The apparatus is similar to the one first developed by Bond; however, in the apparatus used at the Albany Research Center, three paddles instead of just one are situated in the drum which can be
R. D Wilson; J. A Hawk
Abrasive wear testing of dental restorative materials
A tribometer (model ISC-200PC) was modified to form a pin-on-disk type of wear test apparatus. A dental restorative material specimen was used as the pin and a diamond grinding wheel as the abrasive counterface. Both normal and friction forces were recorded during the course of the test. The volumetric wear rate was calculated from the change of length and cross-sectional
Weiping Wang; Anthony T. DiBenedetto; A. Jon. Goldberg
A study of abrasion in steel during comminution
Comminution is a process used in mineral processing for the size reduction of mined material, to permit effective handling, separation and recovery. The equipment used is kinetically complex, with very high-energy impacts and high forces, leading to great amounts of abrasive wear. It is desired to develop a better understanding of these processes, to both measure them and increase comminution while reducing wear. The Steel Wheel Abrasion Test is a laboratory technique used to generate controlled, abrasive three-body wear. By altering the applied force, rotational speed of the wheel and abrasive agent used in the SWAT, the wear behaviour of a material can be quantified. High-stress wear, which occurs when abrasive material is degraded during the test, can replicate the processes occurring in comminution systems. This work has found that abrasive wear will increase with increasing input energy into the tribological interaction. This wear can be linked to the energy input into the system, through the measurement of applied forces, wheel rotational speed and generated torque. This results in the development of a specific abrasion energy, EAS, which provide an energy metric for the abrasion process. Furthermore, the breakage induced in the abrasive particles can also be quantified and evaluated, generating a comminution metric, the specific comminution energy, ECS. These indices can then be linked, to develop an understanding of systems where comminution and abrasion occur concurrently.
Lafleur, Jean-Philippe
Circular Signs of the Rock Abrasion Tool
This image was taken by Mars Exploration Rover Opportunity's front hazard-avoidance camera, providing a circular sign of the success of the rover's first grinding of a rock. The round, shallow hole seen in this image is on a rock dubbed 'McKittrick,' located in the 'El Capitan' area of the larger outcrop near Opportunity's landing site.
Blast furnace injection symposium: Proceedings
These proceedings contain 14 papers related to blast furnace injection issues. Topics include coal quality, coal grinding, natural gas injection, stable operation of the blast furnace, oxygen enrichment, coal conveying, and performance at several steel companies. All papers have been processed separately for inclusion on the data base.
The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process.
Dr. M.A. Ebadian
Propagation of Nonideal Blast Waves.
The propagation of non-ideal blast waves initiated by finite power density sources has been classified into three regimes. The early-time motion of a non-ideal blast reflects the characteristics of the energy-time profile of the particular initiation ener...
C. M. Guirao G. G. Bach J. H. Lee
Blast load assessment using hydrocodes
The evaluation of pressures and impulses produced by blast loads with the aid of hydrocodes is studied in this paper. Numerical results are compared with those obtained with existing analytical expressions for different scaled distances and boundary conditions. In particular, the capacity of both methods to capture multiple reflections of the blast load is analyzed. The effects of mesh size
B. Luccioni; D. Ambrosini; R. Danesi
Comparative Study of Specific Plowing Energy for Mild Steel and Composite Ceramics Using Single Grit Scratch Tests
The present research work compares the specific plowing energy requirement of two different materials: mild steel (ductile material) and composite ceramics (brittle material) using single grit scratch tests. The comparative study of two different materials will enhance the understanding of specific plowing energy. Specific plowing energy depends both on grinding process parameters as well as material property such as hardness.
Vijayender Singh; Sudarsan Ghosh; P. Venkateswara Rao
Starch degradation and nutrition value improvement in corn grits by solid state fermentation technique with Coriolus versicolor.
The study was conducted to evaluate effect of Coriolus versicolor mycelia on degrading starch and improving nutrition value in corn grits through solid state fermentation technique. The results showed that using soybean meal as a nitrogen source, ?-amylase secreted from C. versicolor expressed 407.25U/g of activity, leading to 45.15% of starch degraded. The activity grew with fermentation time until the 15(th) day, after that the amylase was deactivated rapidly. An orthogonal experiment designed for the study illustrated that degradation rate of starch in corn grits attained to maximum, 50.51%, when 100g of corn grits, added 16g of soybean meal, were fermented by C. versicolor for 12 days, in an initial pH 5.5. After fermenting, compared to the nonfermented control, contents of amino acids, total sugar, crude fat and crude protein were increased by 21.00%, 38.45%, 55.56%, 69.15% respectively. The significant improvement of nutrition value in corn grits is probably attributed to the intense metabolism of C. versicolor. PMID:24031762
Huang, Mian; Zhang, Song
Starch degradation and nutrition value improvement in corn grits by solid state fermentation technique with Coriolus versicolor
The study was conducted to evaluate effect of Coriolus versicolor mycelia on degrading starch and improving nutrition value in corn grits through solid state fermentation technique. The results showed that using soybean meal as a nitrogen source, ?-amylase secreted from C. versicolor expressed 407.25U/g of activity, leading to 45.15% of starch degraded. The activity grew with fermentation time until the 15th day, after that the amylase was deactivated rapidly. An orthogonal experiment designed for the study illustrated that degradation rate of starch in corn grits attained to maximum, 50.51%, when 100g of corn grits, added 16g of soybean meal, were fermented by C. versicolor for 12 days, in an initial pH 5.5. After fermenting, compared to the nonfermented control, contents of amino acids, total sugar, crude fat and crude protein were increased by 21.00%, 38.45%, 55.56%, 69.15% respectively. The significant improvement of nutrition value in corn grits is probably attributed to the intense metabolism of C. versicolor.
The development of an inflatable reflector for the External Tank Gamma Ray Imaging Telescope (ET-GRIT)
A thin film inflatable reflector to be evaluated for use in the External Tank Gamma Ray Imaging Telescope (ET-GRIT) has been produced. The stress analysis, materials testing, and reflector design are reviewed, and the patterning of the reflector to approximate a section of a sphere is described. The seam techniques considered for the reflector construction and the determination of the
David Phillip Cadogan
Simulation for the prediction of surface roughness in magnetic abrasive flow finishing (MAFF)
The final machining (or finishing) of precision parts with high level of surface finish and close tolerance is making the application of magnetic abrasive finishing technology increasingly important. Magnetic abrasive flow finishing (MAFF) is a new abrasive finishing process combining the features of abrasive flow finishing (AFF) and magnetic abrasive finishing (MAF). MAFF provides a high level of surface finish
Amit M. Wani; Vinod Yadava; Atul Khatri
Comparison of different abrasion mechanisms on the barrier properties of organic coatings
Since the loss of properties of organic coatings due to abrasion is of primary importance in the material performance, the reduction of barrier properties of organic coatings due to abrasion is studied by electrochemical impedance spectroscopy. The damage of organic coatings caused by abrasion impact of different abrasive materials and abrasion as a result of rubbing aggressive agents against the
Y. Reyes-Mercado; S. Rossi; F. Deflorian; M. Fedel
Possibility of the Abrasive Wear Resistance Determination with Scratch Tester
Abrasion wear resistance is very important in many applications and it is not a surprise that there are many laboratory test\\u000a methods for its determination. In this article, a possibility of the abrasive wear resistance determination with scratch tester,\\u000a as a relatively easy and quick test method, was analysed and compared with the standard test method for pin abrasion testing
A. Vencl; N. Manic �; V. Popovic; M. Mrdak
Analysis of magnetorheological abrasive flow finishing (MRAFF) process
A new precision finishing process called magnetorheological abrasive flow finishing (MRAFF), which is basically a combination\\u000a of abrasive flow machining (AFM) and magnetorheological finishing (MRF), has been developed for nano-finishing of parts even\\u000a with complicated geometry for a wide range of industrial applications. In this paper microstructure of the mixture of magnetic\\u000a and abrasive particles in magnetorheological polishing fluid (MRPF)
Manas Das; V. K. Jain; P. S. Ghoshdastidar
Two-body dry abrasive wear of cermets
The present paper concerns the two-body dry abrasive wear phenomenon of a series of cermets on the base of titanium and chromium carbides with different composition, using a �block on abrasive grinding wheel� test machine. WC�Co hardmetals were used as reference material. Abrasive wear resistance of WC-base hardmetals is superior to that of TiC- and Cr3C2-base cermets. The wear coefficient
J. Pirso; M. Viljus; K. Juhani; S. Letunovit�
The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and construct a pre-prototype of the nozzle, blast head with wind curtain, sensors, and dust separator and test this system to assess the performance of the new design under controlled conditions at the contractor's facility. In phase III, the Contractor shall design and construct a prototype of the High Productivity Vacuum Blasting System, based on the results of the pre-prototype design and testing performed. This unit will be a full-scale prototype and will be tested at a designated Department of Energy (DOE) facility. Based on the results, the system performance, the productivity, and the economy of the improved vacuum blasting system will be evaluated.
William S. McPhee
Machining human dentin by abrasive water jet drilling.
The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 ?m; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin. PMID:24642975
Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike
Critical distance for blast-resistant design
Blast loads have, in the recent past, become important service loads for certain categories of structures. An important task in blast-resistant design is to make a realistic prediction of the blast pressures. The distance of explosion from the structure is an important datum, governing the magnitude and duration of the blast loads. The current practice is to choose some arbitrary
M. V. Dharaneepathy; M. N. Keshava Rao; A. R. Santhakumar
Modeling Coal Seam Damage in Cast Blasting
A discrete element computer program named DMC_BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions. DMC_BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993). Coal seam
S. H. Chung; D. S. Preece
Neurological effects of blast injury.
Over the last few years, thousands of soldiers and an even greater number of civilians have suffered traumatic injuries due to blast exposure, largely attributed to improvised explosive devices in terrorist and insurgent activities. The use of body armor is allowing soldiers to survive blasts that would otherwise be fatal due to systemic damage. Emerging evidence suggests that exposure to a blast can produce neurologic consequences in the brain but much remains unknown. To elucidate the current scientific basis for understanding blast-induced traumatic brain injury (bTBI), the NIH convened a workshop in April 2008. A multidisciplinary group of neuroscientists, engineers, and clinicians were invited to share insights on bTBI, specifically pertaining to: physics of blast explosions, acute clinical observations and treatments, preclinical and computational models, and lessons from the international community on civilian exposures. This report provides an overview of the state of scientific knowledge of bTBI, drawing from the published literature, as well as presentations, discussions, and recommendations from the workshop. One of the major recommendations from the workshop was the need to characterize the effects of blast exposure on clinical neuropathology. Clearer understanding of the human neuropathology would enable validation of preclinical and computational models, which are attempting to simulate blast wave interactions with the central nervous system. Furthermore, the civilian experience with bTBI suggests that polytrauma models incorporating both brain and lung injuries may be more relevant to the study of civilian countermeasures than considering models with a neurologic focus alone. PMID:20453776
Hicks, Ramona R; Fertig, Stephanie J; Desrocher, Rebecca E; Koroshetz, Walter J; Pancrazio, Joseph J
Neurological Effects of Blast Injury
Over the last few years, thousands of soldiers and an even greater number of civilians have suffered traumatic injuries due to blast exposure, largely attributed to improvised explosive devices in terrorist and insurgent activities. The use of body armor is allowing soldiers to survive blasts that would otherwise be fatal due to systemic damage. Emerging evidence suggests that exposure to a blast can produce neurological consequences in the brain, but much remains unknown. To elucidate the current scientific basis for understanding blast-induced traumatic brain injury (bTBI), the NIH convened a workshop in April, 2008. A multidisciplinary group of neuroscientists, engineers, and clinicians were invited to share insights on bTBI, specifically pertaining to: physics of blast explosions, acute clinical observations and treatments, preclinical and computational models, and lessons from the international community on civilian exposures. This report provides an overview of the state of scientific knowledge of bTBI, drawing from the published literature, as well as presentations, discussions, and recommendations from the workshop. One of the major recommendations from the workshop was the need to characterize the effects of blast exposure on clinical neuropathology. Clearer understanding of the human neuropathology would enable validation of preclinical and computational models, which are attempting to simulate blast wave interactions with the central nervous system. Furthermore, the civilian experience with bTBI suggests that polytrauma models incorporating both brain and lung injuries may be more relevant to the study of civilian countermeasures than considering models with a neurological focus alone.
Hicks, Ramona R.; Fertig, Stephanie J.; Desrocher, Rebecca E.; Koroshetz, Walter J.; Pancrazio, Joseph J.
Controlled toothbrush abrasion of softened human enamel.
The aim of this in vitro study was to compare toothbrush abrasion of softened enamel after brushing with two (soft and hard) toothbrushes. One hundred and fifty-six human enamel specimens were indented with a Knoop diamond. Salivary pellicle was formed in vitro over a period of 3 h. Erosive lesions were produced by means of 1% citric acid. A force-measuring device allowed a controlled toothbrushing force of 1.5 N. The specimens were brushed either in toothpaste slurry or with toothpaste in artificial saliva for 15 s. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% CI) were recorded in ten treatment groups: (1) soft toothbrush only [28 (17-39) nm]; (2) hard toothbrush only [25 (16-34) nm]; (3) soft toothbrush in Sensodyne MultiCare slurry [46 (27-65) nm]; (4) hard toothbrush in Sensodyne MultiCare slurry [45 (24-66) nm]; (5) soft toothbrush in Colgate sensation white slurry [71 (55-87) nm]; (6) hard toothbrush in Colgate sensation white slurry [85 (60-110) nm]; (7) soft toothbrush with Sensodyne MultiCare [48 (39-57) nm]; (8) hard toothbrush with Sensodyne MultiCare [40 (29-51) nm]; (9) soft toothbrush with Colgate sensation white [51 (37-65) nm]; (10) hard toothbrush with Colgate sensation white [52 (36-68) nm]. Neither soft nor hard toothbrushes produced significantly different toothbrush abrasion of softened human enamel in this model (p > 0.05). PMID:18663297
Voronets, J; Jaeggi, T; Buergin, W; Lussi, A
Blast From the Past
NSDL National Science Digital Library
A recently recovered deep-sea core supports theories that an asteroid collided with the earth 65 million years ago, around the time of the extinction of the dinosaurs. The Smithsonian Institution National Museum of Natural History's new site, Blast from the Past, contains details on this cataclysmic event. Colorful graphics provide conceptual illustrations of the asteroid impact and aftermath, accompanied by photographs of the deep-sea core. Text summaries, followed by bibliographic references, describe the asteroid hypothesis, the Cretaceous/Tertiary (K/T) boundary, and the utility of deep-sea cores. With links to other paleobiological sites and related museum exhibits, this site is a useful resource for those wanting to know more about fateful asteroid impacts.
Toxicology of blast overpressure.
Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that are occurring worldwide with greater frequency. Exposure to incident BOP waves can cause auditory and non-auditory damage. The primary targets for BOP damage are the hollow organs, ear, lung and gastrointestinal tract. In addition, solid organs such as heart, spleen and brain can also be injured upon exposure. However, the lung is more sensitive to damage and its injury can lead to death. The pathophysiological responses, and mortality have been extensively studied, but little attention, was given to the biochemical manifestations, and molecular mechanism(s) of injury. The injury from BOP has been, generally, attributed to its external physical impact on the body causing internal mechanical damage. However, a new hypothesis has been proposed based on experiments conducted in the Department of Respiratory Research, Walter Reed Army Institute of Research, and later in the Department of Occupational Health, University of Pittsburgh. This hypothesis suggests that subtle biochemical changes namely, free radical-mediated oxidative stress occur and contribute to BOP-induced injury. Understanding the etiology of these changes may shed new light on the molecular mechanism(s) of injury, and can potentially offer new strategies for treatment. In this symposium. BOP research involving auditory, non-auditory, physiological, pathological, behavioral, and biochemical manifestations as well as predictive modeling and current treatment modalities of BOP-induced injury are discussed. PMID:9217311
Elsayed, N M
Abrasion-Resistant Coating for Flexible Insulation
Ceramic coating increases durability and heat resistance of flexible high-temperature insulation. Coating compatible with quartz-fabric insulation allowing it to remain flexible during and after repeated exposures to temperatures of 1,800 degree F (982 degree C). Prevents fabric from becoming brittle while increasing resistance to aerodynamic abrasion and loading. Coating consists of penetrating precoat and topcoat. Major ingredients high-purity colloidal silica binder and ground silica filler, which ensure stability and compatibility with fabric at high temperatures. Both precoat and topcoat cured at room temperature.
Mui, D.; Headding, R. E.
Mars Pathfinder Wheel Abrasion Experiment Ground Test
The National Aeronautics and Space Administration (NASA) sent a mission to the martian surface, called Mars Pathfinder. The mission payload consisted of a lander and a rover. The primary purpose of the mission was demonstrating a novel entry, descent, and landing method that included a heat shield, a parachute, rockets, and a cocoon of giant air bags. Once on the surface, the spacecraft returned temperature measurements near the Martian surface, atmosphere pressure, wind speed measurements, and images from the lander and rover. The rover obtained 16 elemental measurements of rocks and soils, performed soil-mechanics, atmospheric sedimentation measurements, and soil abrasiveness measurements.
Keith, Theo G., Jr.; Siebert, Mark W.
NCBI BLAST: a better web interface
Basic Local Alignment Search Tool (BLAST) is a sequence similarity search program. The public interface of BLAST, http:\\/\\/www.ncbi.nlm.nih.gov\\/ blast, at the NCBI website has recently been reengineered to improve usability and performance. Key new features include simplified search forms, improved navigation, a list of recent BLAST results, saved search strategies and a documentation directory. Here, we describe the BLAST web
Mark Johnson; Irena Zaretskaya; Yan Raytselis; Yuri Merezhuk; Scott Mcginnis; Thomas L. Madden
Portable convertible blast effects shield
A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.
Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)
Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)
A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.
Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A. (Livermore, CA)
Blasting, graphical interfaces and Unix.
A discrete element computer program, DMC (Distinct Motion Code) was developed to simulate blast-induced rock motion. To simplify the complex task of entering material and explosive design parameters as well as bench configuration, a full-featured graphica...
S. Knudsen D. S. Preece
Laboratory abrasive wear tests: investigation of test methods and alloy correlation
When screening materials, laboratory abrasive wear testing is a quick and inexpensive way of obtaining large quantities on information on wear rates and wear mechanisms. Typical laboratory abrasive wear tests approximate two- and three-body abrasion. The Albany Research Center, however, uses a suite of four laboratory abrasion, gouging�abrasion, and impact�gouging abrasion wear tests to rank materials for wear applications in
J. A. Hawk; R. D. Wilson; J. H. Tylczak; �. N. Do?an
Water blasting paint removal methods
Water blasting is a paint removal technique that has been used for cleaning and paint removal for many years. The major disadvantages until recently were the slow rate of paint removal and the possibility of damage to the substrate from the high pressures used. With the improvement in nozzle design that allows for higher operating pressures and the use of environmentally compliant paint softeners or strippers, water blasting is becoming a recognized technique for paint removal in the aircraft industry.
Rate-sensitive numerical analysis of dynamic responses of arched blast doors subjected to blast loading
Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions\\u000a and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response\\u000a of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door\\u000a under blast loading were analyzed
Li Chen; Qin Fang; Yi Zhang; Yadong Zhang
Optimal composition of ceramic binder for highly porous abrasive tools
1043 The operational characteristics of abrasive tools largely depend on the structure and properties of the materials from which they are made. Machining experience shows that highly porous abrasive tools are the most effective. In comparison with standard tools, their productivity is higher, while the depth of the defect layer in the ground surface is smaller by a factor of
V. I. Kurdyukov; A. A. Andreev; A. N. Sychugov
Magnetic abrasive finishing (MAF) uses magnetic force of very low magnitude applied on ferromagnetic abrasive particles to obtain very high level surface finish. The process has been investigated extensively in the finishing of cylindrical surfaces. This paper reports an experimental work on the analysis of surface roughness and material removal using response surface method in the MAF of plane surfaces.
Berhanu Girma; Suhas S. Joshi; M. V. G. S. Raghuram; R. Balasubramaniam
Elucidating the Optimal Parameters in Magnetic Finishing with Gel Abrasive
Magnetic finishing with gel abrasives (MFGA) created an excellent efficiency in the polishing process. They were not only easily produced but recycled after machining as well. The silicone gel, which was then chosen as the medium in this study, played a crucial role to locate the abrasion behavior and establish the mechanism of MFGA. In the article, polishing efficiencies with
A. Cheng Wang; L. Tsai; C. H. Liu; K. Z. Liang; S. J. Lee
Rheological Properties of a Powder Magnetic Abrasive Tool
Specific frictional forces have been examined for a magnetic abrasive tools as affected by the parameters of the machining in wide magnetic gaps. Such a tools have liquid characteristics and can be considered as viscoplastic medium. The viscosity varies with the cutting speed and when there is any change between laminar and turbulent behavior of the magnetic abrasive particles, in
Viktor S. Maiboroda
Improving Electrical Discharge Machined Surfaces Using Magnetic Abrasive Finishing
A recast layer is invariably present on surfaces produced by electrical discharge machining (EDM). For some metals with high hardness, the recast layer may contain micro-cracks. This damaged layer can affect the service life of the parts produced by this method. This investigation demonstrates that magnetic abrasive finishing (MAF) process using unbonded magnetic abrasives (UMA), can improve the quality of
Biing-Hwa Yan; Geeng-Wei Chang; Jung-Hsien Chang; Rong-Tzong Hsu
The research of contaminant abrasion on external gear pump
Leakage brings out contamination inevitably and contaminant abrasion leads to the increase of internal leakage, the decline of volumetric efficiency, and the service life. The influential factors were found by experiment in the paper. On the basis of the experiment of gear pump contaminant abrasion sensibility, we discuss the interaction between leakage and contamination, provide reference for decreasing the leakage
Baode Jing; Lijuan Yang; Shuang Lu
Friction and abrasive wear of UHWMPE sliding on ice
The authors present an experimental approach of abrasion resistance of material currently used in ski: ultra high molecular weight polyethylene (UHMWPE) is used as the main element of ski sole: cross country skiing, speed skiing, alpine skiing, �.The aim of this work is to characterise abrasive wear and tribological performance of ski sole when one slides on ice in different
S. Ducret; H. Zahouani; A. Midol; P. Lanteri; T. G. Mathia
Abrasion of 6 dentifrices measured by vertical scanning interference microscopy
Objectives The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Material and Methods Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Results Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix� produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Conclusion Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials.
PASCARETTI-GRIZON, Florence; MABILLEAU, Guillaume; CHAPPARD, Daniel
Microwave sintering of sol-gel derived abrasive grain
A method is provided for making microwave-sintered, free flowing alpha alumina-based ceramic abrasive grain, under conditions effective to couple microwaves with calcined alpha alumina-based abrasive gain precursor and sinter it at a temperature of at least about 1150.degree. C.
Plovnick, Ross (St. Louis Park, MN); Celikkaya, Ahmet (Woodbury, MN); Blake, Rodger D. (Tuscon, AZ)
Machinability of Abrasion Resistance Cast Iron with PCBN Cutting Tools
Highly abrasion and erosive resistance materials are an important group of materials and has very wide applications in many industrial areas. The characteristic properties for this material include the castability and the superior wear resistance. The material, however, is in the group of hard-to-machine materials due to its abrasion to cutting tool and low thermal conductivity. In this article, the
J. M. Zhou; M. Andersson
Experimental investigations into rotating workpiece abrasive flow finishing
Abrasive flow finishing (AFF) is used to deburr, polish or radius surfaces and edges by flowing a semisolid abrasive medium over the intended surface to be finished. Such finishing operations play a crucial role in manufacturing process of machine parts. The cost escalates sharply when the requirement is to achieve surface roughness values near nano levels. The need for finishing
Mamilla Ravi Sankar; V. K. Jain; J. Ramkumar
Modelling the abrasive flow machining process on advanced ceramic materials
Abrasive flow machining (AFM) is a unique machining method used to achieve high surface quality on inner, difficult-to-access and on outside contours. Using AFM, it is possible to realise predefined edge rounding on any brittle or hard material. AFM is easy to integrate in an automated manufacturing environment. The abrasive medium applied during AFM is a fluid consisting of a
Eckart Uhlmann; Vanja Mihotovic; Andre Coenen
Fluid flow analysis of magnetorheological abrasive flow finishing (MRAFF) process
A new precision finishing process called magnetorheological abrasive flow finishing (MRAFF), which is basically a combination of abrasive flow machining (AFM) and magnetorheological finishing (MRF), has been developed for nano-finishing of parts even with complicated geometry for a wide range of industrial applications. This paper deals with the theoretical investigations into the mechanism of MRAFF process to study the effects
The Size Effect in Abrasion of Dual-Phase Alloys
The abrasion rate of an alloy has generally been found to be a function of the abrasive particle size, decreasing rapidly for particle sizes below about 100 microns, and the same general behavior is found for erosion by solid particle impact. Most previous investigations of this effect have been confined to single-phase alloys or steels having second-phase particles which are
T. H. Kosel; S. Z. Li; C. M. Rao
Soil Aggregate Abrasion by Impacting Sand and Soil Particles
D URING wind erosion, erodible particles (< 0.85 mm diameter) are removed continually in saltation and suspension, but the supply of particles is rarely exhausted because new erodible-size particles are created constantly by abrasion. Little is known about the physics of soil abrasion, however. This study was undertaken to determine the effects of particle speed, size, impact angle, and stability
L. J. Hagen
Coated Abrasive Machining of Titanium Alloys with Inorganic Phosphate Solutions
Titanium alloys designed for aerospace applications are extremely difficult to grind. Although the high strength of these alloys is a major cause of poor grindability, chemical adhesion of the titanium to the abrasive grain is also a factor contributing to poor abrasive performance. These difficulties can be alleviated by proper choice of grinding fluid. This paper describes work in which
I. S. Hong; E. J. Duwell; W. J. McDonald; C. E. Mereness
Failure analysis of an abrasive cut-off wheel
The relationship between composition, structure, properties and performance is central to the design, use and failure analysis of engineering components. Thermogravimetric analysis (TGA) and wavelength X-ray fluorescence (WRXF) were applied in evaluating the elemental composition and thermal properties, respectively, of a failed abrasive cut-off wheel. The cutting tool, consisting of a bonded abrasive disc, failed prematurely during the routine sectioning
A. T. Riga; C. G. Scott
Laser Surface Preparation and Bonding of Aerospace Structural Composites
A Nd:YAG laser was used to etch patterns conducive to adhesive bonding onto CFRP surfaces. These were compared to typical pre-bonding surface treatments including grit blasting, manual abrasion, and peel ply. Laser treated composites were then subjected to optical microscopy, contact angle measurements, and post-bonding mechanical testing.
Belcher, Marcus A.; Wohl, Christopher J.; Connell, John W.
Method for removing surface-damaged layers from nickel alloys
Electrical discharge machining /EDM/ damaged layer can be effectively removed from Rene 41, Inconel 625, Inconel 718, and Monel K-500 by abrasive-grit blasting or electropolishing /at room temperature/ at a current density of 5A/inches squared in a water solution of phosphoric and sulfuric acids.
Fawley, R. W.
EPA Science Inventory
This report describes a comparative technical and economic evaluation of using a dustless needlegun system versus a conventional abrasive grit blasting system in the removal of lead-based paint from steel structures. he objective of the study was to comparatively analyze the oper...
This report describes a comparative technical and economic evaluation of using a dustless needlegun system versus a conventional abrasive grit blasting system in the removal of lead-based paint from steel structures. The objective of the study was to comparatively analyze the ope...
Solidification structure and abrasion resistance of high chromium white irons
Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification paths, and resulting microstructures when poured with varying superheats. Completely equiaxed macrostructures were produced in thick section castings with slightly hypereutectic compositions. High-stress abrasive wear tests were then performed on the various alloys to examine the influence of both macrostructure and microstructure on wear resistance. Results indicated that the alloys with a primarily austenitic matrix had a higher abrasion resistance than similar alloys with a pearlitic/bainitic matrix. Improvement in abrasion resistance was partially attributed to the ability of the austenite to transform to martensite at the wear surface during the abrasion process.
Do?an, �. N.; Hawk, J. A.; Laird, G.
Solidification Structure and Abrasion Resistance of High Chromium White Irons
Dogan, O.N.; Hawk, J.A.; Laird, George, II
Tyre-blast injuries.
A teenager college student was fatally injured by burst tyre air pressure while waiting on a public bus stand to catch a bus to reach her college at Kuala Lumpur. She accidentally came near the wheel while boarding when tube and tyre got burst .The air pressure had blown the girl in the air and she subsequently fell on a rough surface. The iron-locking rim of the wheel acted as a missile and hit the girl. She died on her way to the hospital. A medico-legal autopsy was performed which showed extensive injuries in the cranial and chest cavity. Head had large scalp laceration with diffuse separation and gaping from in the vault region; skull bones were fractured. Chest cavity had extensive rib fractures, lacerated lungs and haemo-thorax while externally there was no obvious injury. It requires intensive care management and screening of the victims. Tyre-blast injuries are not so common. This case exposes the hazard due to burst tyre. PMID:19329081
Murty, O P
Head Kinematics Resulting from Simulated Blast Loading Scenarios.
Blast wave overpressure has been associated with varying levels of traumatic brain injury in soldiers exposed to blast loading. In realistic blast loading scenarios, the mechanisms of primary blast injury are not well known due to the complex interactions...
A. Bouamoul D. Singh D. S. Cronin P. A. Lockhart T. N. Haladuick
Silicon slicing by fixed abrasive slicing technique
One of the major cost factors in silicon ingot technology adaptation for terrestrial photovoltaic application is in slicing boules into wafers. The most developed industrial practice is the Internal Diameter (ID) slicing. This method utilizes diamond cutting. The diamond stands up for long periods, hence, the cost of expendable materials is low. However, the ID technology as practiced today has poor material utilization. The Multiblade Slurry (MBS) method has low equipment and labor costs but its expendable material costs are high. Recently Multiwire Slurry (MWS) technology has shown very good material utilization, but its expendable material costs are even higher than MBS. The multiwire Fixed Abrasive Slicing Technique (FAST) still in advanced development stage, combines the low expendable material costs of ID method, the low labor and equipment costs of MBS and high material utilization of MWS.
Schmid, F.; Khattak, C. P.
Pipeline abrasion coatings survive extended bottom tow
Pipeline bottom-tow tests for Placid Oil Co.'s Green Canyon Block 29 (Gulf of Mexico) project have supported the technical feasibility of applying abrasion coatings that will survive bottom towing over distances greater than 450 nautical miles. The tests were completed off the Texas Coast in June of last year by R. J. Brown and Associates of America Inc. (RJBA), Houston. Placid Oil has chosen this method for its Green Canyon project which will include installation of four flowlines of 16 miles total length and 10 miles of 14 and 16-in. export lines. The decision was based on depth limitations for installation and tie-in techniques. Depths range from 1,540 ft at the Block 29 template to 2,300 ft at the satellite well in Block 31.
Brown, R.J.
Tooth wear: attrition, erosion, and abrasion.
Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification acts through a distinct process that is associated with unique clinical characteristics. Accurate prevalence data for each classification are not available since indices do not necessarily measure one specific etiology, or the study populations may be too diverse in age and characteristics. The treatment of teeth in each classification will depend on identifying the factors associated with each etiology. Some cases may require specific restorative procedures, while others will not require treatment. A review of the literature points to the interaction of the three entities in the initiation and progression of lesions that may act synchronously or sequentially, synergistically or additively, or in conjunction with other entities to mask the true nature of tooth wear, which appears to be multifactorial. PMID:12859088
Litonjua, Luis A; Andreana, Sebastiano; Bush, Peter J; Cohen, Robert E
By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of the disk in a pin-on-disk wear tester, and the accurate control of both the impact energy delivered to the specimen and the total sliding distance of the specimen on the anvil. Statistical analysis of test results on the machine with EN24 steel and cast high manganese steel shows that the uncertainty of the population mean is within +/- 4.7% of the sample mean under a 95% confidence level of student distribution, which indicates a very good accuracy of test.
Zhang, D.; Beeley, P. R.; Baker, A. J.
Fate of Fusarium mycotoxins in maize flour and grits during extrusion cooking.
Extrusion technology is used widely in the manufacture of a range of breakfast cereals and snacks for human consumption and animal feeds. To minimise consumer exposure to mycotoxins, the levels of deoxynivalenol (DON) and zearalenone (ZON) in cereals/cereal products and fumonisins B(1) and B(2) (FB(1) and FB(2)) in maize are controlled by European Union legislation. Relatively few studies, however, have examined the loss of Fusarium mycotoxins during processing. The behaviour of FB(1), FB(2) and fumonisin B(3) (FB(3)), DON and ZON during extrusion of naturally contaminated maize flour and maize grits is examined using pilot-scale equipment. DON and ZON are relatively stable during extrusion cooking but the fumonisins are lost to varying degrees. There is some loss of ZON when present in low concentrations and extruded at higher moisture contents. The presence of additives, such as reducing sugars and sodium chloride, can also affect mycotoxin levels. Moisture content of the cereal feed during extrusion is important and has a greater effect than temperature, particularly on the loss of fumonisins at the lower moistures. The effects are complex and not easy to explain, although more energy input to the extruder is required for drier materials. However, on the basis of these studies, the relationship between the concentration of Fusarium toxins in the raw and finished product is toxin- and process-dependent. PMID:19680845
Scudamore, Keith A; Guy, Robin C E; Kelleher, Brian; MacDonald, Susan J
The effects of abrasives on electrical submersible pumps
The electrical submersible pump (ESP) is a high-speed rotating device. Its operational life in oil wells can depend on the type and quantities of abrasives present in the produced fluid. This paper reports on a set of experiments performed in a specialized abrasive test loop. In the test, the size and quantity of abrasives were varied along with flow rate through the pump. This paper also examines recent literature on sand production and explores some of the practical problems in sand measurement.
Wilson, B.L. (Oil Dynamics Inc., Tulsa, OK (US))
Method for forming an abrasive surface on a tool
A method for fabricating a tool used in cutting, grinding and machining operations, is provided. The method is used to deposit a mixture comprising an abrasive material and a bonding material on a tool surface. The materials are propelled toward the receiving surface of the tool substrate using a thermal spray process. The thermal spray process melts the bonding material portion of the mixture, but not the abrasive material. Upon impacting the tool surface, the mixture or composition solidifies to form a hard abrasive tool coating.
Seals, R.D.; White, R.L.; Swindeman, C.J.; Kahl, W.K.
Seals, Roland D. (Oak Ridge, TN); White, Rickey L. (Harriman, TN); Swindeman, Catherine J. (Knoxville, TN); Kahl, W. Keith (Knoxville, TN)
Low Cost Oxygen for Blast Furnace.
A low cost process is examined which provides oxygen enrichment of blast air for blast furnaces to increase steel production without increasing the steelmaking or final finishing facilities. The proposed process is designed to separate the oxygen from nit...
R. Jablin
30 CFR Blasting - Surface and Underground
...2010-07-01 false Surface and Underground Blasting Electric Blasting Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...in the same work area shall be initiated from one source. Electric Blasting�Surface and...
Blasting, graphical interfaces and Unix
A discrete element computer program, DMC (Distinct Motion Code) was developed to simulate blast-induced rock motion. To simplify the complex task of entering material and explosive design parameters as well as bench configuration, a full-featured graphical interface has been developed. DMC is currently executed on both Sun SPARCstation 2 and Sun SPARCstation 10 platforms and routinely used to model bench and crater blasting problems. This paper will document the design and development of the full-featured interface to DMC. The development of the interface will be tracked through the various stages, highlighting the adjustments made to allow the necessary parameters to be entered in terms and units that field blasters understand. The paper also discusses a novel way of entering non-integer numbers and the techniques necessary to display blasting parameters in an understandable visual manner. A video presentation will demonstrate the graphics interface and explains its use.
Knudsen, S. [RE/SPEC, Inc., Albuquerque, NM (United States); Preece, D.S. [Sandia National Labs., Albuquerque, NM (United States)
Prediction System of Magnetic Abrasive Finishing (MAF) on the Internal Surface of a Cylindrical Tube
This study mainly used magnetic abrasive finishing (MAF) to explore a stainless steel SUS304 cylindrical tube related to the processing characteristic and the prediction system. The self-made adjustable electricity polishing mechanism was assembled on a magnetic abrasive machine. The cylindrical stainless steel tube was filled with magnetic abrasive, which consisted of sintered iron and aluminum oxide powder. Magnetic abrasive in
Ching-Lien Hung; Wei-Liang Ku; Lieh-Dai Yang
BLAST: improvements for better sequence analysis
Basic local alignment search tool (BLAST) is a sequence similarity search program. The National Center for Biotechnology Information (NCBI) main- tains a BLAST server with a home page at http:\\/\\/ www.ncbi.nlm.nih.gov\\/BLAST\\/. We report here on recent enhancements to the results produced by the BLAST server at the NCBI. These include features to highlight mismatches between similar sequences, showwherethequerywasmaskedforlow-complexity sequence, and
Jian Ye; Scott Mcginnis; Thomas L. Madden
Blast waves in rotating media.
The model investigated involves a cylindrically symmetric blast wave generated by an infinitely long line explosion in a cold and homogeneous gas rotating rigidly in its self-gravitational field. It is found that within the context of rotation in a gravitational field a blast wave will not adopt the one-zone form familiar from similarity solutions but, rather, a two-zone form. The inner compression zone arises as a response to the presence of the restoring force, which drives a rarefaction wave into the outer compression zone.
Rossner, L. F.
Explosive blasting method and means
An explosive blasting method and apparatus are claimed for producing rock fragmentation and reducing the amplitude of seismic effects (ground vibration) in the vicinity of the blast. It utilizes an air gap method and apparatus for superheating the air surrounding the charge in a borehole. This raises the pressure therein coupled with the use of multiple detonation points along the borehole for the reduction of burn time. This reduces the quantity of explosives used along with a marked reduction of seismic shock, sound, and dust effects to the surrounding area.
Bowling, D.S.; Moore, R.N.
Community response to blast noise
Although community response to impulsive noise from military operations is usually discussed for NEPA-related purposes in terms of the prevalence of annoyance, it is managed on a local, daily basis in terms of numbers of recent complaints. Reconciling blast noise complaint rates with the annoyance predicted by dosage-effect analysis would be of considerable benefit to the Army, since it would provide insight into the dynamics of community reaction to this distinctive form of noise exposure, and put its assessment and management on a common footing. This paper describes a systematic approach to the challenges of quantifying community reaction to blast noise. [Work supported by ERDC-CERL.
Nykaza, Edward T.; Pater, Larry L.; Fidell, Sanford; Schomer, Paul
Simulation of Blast Waves with Headwind
The blast wave resulting from an explosion was simulated to provide guidance for models estimating risks for human spacecraft flight. Simulations included effects of headwind on blast propagation, Blasts were modelled as an initial value problem with a uniform high energy sphere expanding into an ambient field. Both still air and cases with headwind were calculated.
Olsen, Michael E.; Lawrence, Scott W.; Klopfer, Goetz H.; Mathias, Dovan; Onufer, Jeff T.
Blast casting requires fresh assessment of methods
The article says that because blast casting differs from conventional blasting, our ideas about explosive products, drilling, and initiating methods must change. The author discusses how to select a casting explosive and what factors are important in its selection. He also looks at how to determine the best blasthole diameter and burden blasting pattern.
Pilshaw, S.R.
Method of loading blast hole with explosive
A technique for loading an ammonium nitrate-fuel oil (ANFO) explosive mixture upward into a vertical blast hole is discussed. The blast hole may extend as much as 70 ft or more from the open end at the face of the rock structure into which the blast hole is drilled. In order to achieve adequate packing in the hole, the ANFO
29 CFR 1926.912 - Underwater blasting.
...2013-07-01 2013-07-01 false Underwater blasting. 1926.912 Section 1926...the Use of Explosives § 1926.912 Underwater blasting. (a) A blaster shall...of explosives aboard vessels used in underwater blasting operations shall be...
This patent describes a pressure pot system for supplying blasting media under pressure to a pressurized blasting conduit for feeding blasting media to one or more blasting guns, the system including a media storage means and a first and second pressure chambers with means for pressurizing and exhausting the first and second chambers, the media storage means being stacked above the pressure chambers with the first pressure chamber stacked above the second pressure chamber; first and second media valve means for providing communication between the storage means and the first pressure chamber and between the pressure chambers, respectively; air valve means for controlling the air pressurizing and exhausting of the first and second pressure chambers, the improvement comprising: means for opening and closing the first and second media valve means and the air valve means, the first, second and air valve means being offset from each other in both vertical and horizontal dimensions; push rods extending vertically upward from the valve means and spaced one from the other for actuating the valve means to open and close the same; an overhead cam shaft means mounted above the push rods and having a plurality of spaced cams, each of the cams being aligned and operatively associated with one of the push rods for actuating the push rods and thereby the valve means to control the opening and closing of the first and second media valve means and the air valve means; and actuating means for actuating the cam shaft means.
Van Kuiken, L.L. Jr.
Estimating Rock Strength Parameters from Rock Abrasion Tool (RAT) Grinds
We have developed an empirical correlation between rock abrasion tool (RAT) grind energy and compressive strength. This correlation can be used to infer the physical properties of rocks ground by the MER rovers on Mars.
Thomson, B. J.; Bridges, N. T.; Cohen, J.; Hurowitz, J.; Lennon, A.
Simultaneous corrosion and abrasion measurements under grinding conditions
The contribution of corrosion to the abrasive-corrosive wear of high carbon low alloy steel (HCLA), commonly used for grinding balls, was evaluated in 15% quartz slurries. Results were compared with similar results for mild steel. The magnitude of the synergistic effect of corrosion and abrasion was determined for various conditions of applied load, hardness and pH. Measurements were made using a specially constructed ''rotating cylinder-anvil'' apparatus. The synergistic effect is considerable even if the corrosion component of the wear is small. The macroremoval of metal particles, producing the synergistic effect, may be considered to be due to the initiation and propagation of pitting and/or microcracks assisted to anodic corrosion. Corrosion of HCLA steel increased with higher load and lower pH. The magnitude of the corrosive-abrasive wear is determined essentially by pure abrasion and the synergistic effect.
Kotlyar, D.; Pitt, C.H.; Wadsworth, M.E.
Study of abrasive resistance of composites for dental restoration by ball-cratering
Two-body abrasion occurs in the mouth whenever there is tooth-to-tooth contact. This is what most dentists call attrition. Abrasive wear may also occur when there is an abrasive slurry interposed between two surfaces, such that the two solid surfaces are not actually in contact, this is called three-body abrasion, with food acting as the abrasive agent, and occurs in the
P. Vale Antunes; A. Ramalho
Clinical Outcome of 802 Immediately Loaded 2-stage Submerged Implants with a New Grit-Blasted and Acid-Etched Surface: 12-month Follow-up
Purpose: The aim of this study was to evaluate the clinical outcome of delayed or immediately loaded implants of 3 different implant macrodesigns. The hypothesis was that no significant differences in implant success would be observed between immediately and delayed loaded implants. Materials and Methods: Between July 2003 and December 2003, 321 patients were consecutively enrolled for this study. Immediate
Marco Degidi; Adriano Piattelli; Peter Gehrke; Francesco Carinci
Modeling of Polishing Mechanism in Magnetic Abrasive Polishing
Magnetic Abrasive Polishing (MAP) is a super-finishing process primarily used for polishing of non- magnetic and hard materials like, ceramics and stainless steel. This paper deals with the detailed parametric study in polishing of stainless steel work surface. Statistically designed experiments based on Taguchi methods show that size-ratio, tool-work surface clearance, polishing speed, magnetic abrasive diameter and polishing time have
M. G. V. S. Raghuram; Suhas S. Joshi
Material removal mechanisms in non-contact ultrasonic abrasive machining
In this paper, we propose a new non-contact ultrasonic abrasive machining (NUAM) method that is performed using loose abrasives excited by ultrasonic energy in a liquid, and discuss its suitability for application to ultra-precision machining. A horn attached to the ultrasonic generator, having a resonance frequency of 28kHz and an amplitude of 20?m, has been used as a processing tool.
Y. Ichida; R. Sato; Y. Morimoto; K. Kobayashi
Abrasive wear of aluminium composites�a review
Aluminium-silicon alloys and aluminium-based metal-matrix composites (MMCs) containing hard particles offer superior operating performance and resistance to wear. In industrial processes where abrasive slurries are transported by rotating paddles or impellers, clements fabricated from MMC materials provide higher abrasive resistance and therefore a longer service life compared to those made from iron or nickel-based alloys. Composites characterized by a hardness
R. L. Deuis; C. Subramanian; J. M. Yellup
Three-body abrasive wear testing of soft materials
This paper investigates some of the problems associated with determining the `three-body' (rolling particle) abrasion resistance of soft materials such as polymers and soft metals. The ball-cratering micro-scale abrasion apparatus, initially developed for testing hard coatings, has been used to study the behaviour of soft materials: polymethylmethacrylate (PMMA), commercially pure aluminium, tool steel and, as a reference hard material, glass-bonded
R. I Trezona; I. M Hutchings
Effects of vascular fiber content on abrasive wear of bamboo
Natural biomaterials have unique structures and some distinguishing properties for adapting themselves to natural surroundings. Bamboo is a natural composite reinforced with longitudinal fibers (vascular fibers). The abrasive wear property of the cross section of bamboo (Phyllostachys pubescens) stem was examined. The abrasive material used for tests was the mixture of quartz sand (96.5wt.%) and powdered bentonite (3.5wt.%) and contained
Jin Tong; Yunhai Ma; Donghui Chen; Jiyu Sun; Luquan Ren
Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil
A NACA 4415 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from {minus}10{degree} to +40{degree} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, these were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Steady state results of the NACA 4415 testing at Reynolds number of 1.25 million showed a baseline maximum lift coefficient of 1.30 at 12.3{degree} angle of attack. The application of LEGR reduced the maximum lift coefficient by 20% and increased the 0.0090 minimum drag coefficient value by 62%. The zero lift pitching moment of {minus}0.0967 showed a 13% reduction in magnitude to {minus}0.0842 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {+-}5.5{degree} and {+-}10{degree}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude, and both unsteady maximum lift coefficients were greater than the steady state values. Stall is delayed on the airfoil while the angle of attack is increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack. In addition, with LEGR, the hysteresis behavior persisted into lower angles of attack than for the clean case.
Hoffmann, M.J.; Reuss Ramsay, R.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)
Although community response to impulsive noise from military operations is usually discussed for NEPA-related purposes in terms of the prevalence of annoyance, it is managed on a local, daily basis in terms of numbers of recent complaints. Reconciling blast noise complaint rates with the annoyance predicted by dosage-effect analysis would be of considerable benefit to the Army, since it would
Edward T. Nykaza; Larry L. Pater; Sanford Fidell; Paul Schomer
Strong Blast Wave Computer Programs.
This report describes a computer program package for the computation of the flow field within a strong blast bubble. The programs are based on Sedov-Laporte-Chang formulas and compute any of the following: shock front location and corresponding flow value...
A. Celmins
Drill and Blast Tunneling Practices
High-performance drill and blast methods for tunnel construction require that each of the individual working elements that constitute the construction process are optimized and considered as a system of sequential and parallel activities. The advantage of integrating the logistic backup systems facilitates an increase in performance. To achieve increased production, it is necessary to improve the drilling, explosive loading, temporary
Gerhard Girmscheid; Cliff Schexnayder
A discrete element computer program, DMC (Distinct Motion Code) was developed to simulate blast-induced rock motion. To simplify the complex task of entering material and explosive design parameters as well as bench configuration, a full-featured graphical interface has been developed. DMC is currently executed on both Sun SPARCstation 2 and Sun SPARCstation 10 platforms and routinely used to model bench
S. Knudsen; D. S. Preece
Gun Blast from Naval Guns.
The available data on gun blasts from naval guns are complied utilizing computer curve fitting techniques. Curves of peak free-air pressure are presented for all naval guns, ranging in size from 20 mm to 16in./50. In addition, curves of arrival time, dura...
M. F. Walther
Method of protecting surfaces from abrasion and abrasion resistant articles of manufacture
Surfaces of fabricated structures are protected from damage by impacting particulates by a coating of hard material formed as a mass of thin flexible filaments having root ends secured to the surface and free portions which can flex and overlap to form a resilient cushioning mat which resembles hair or fur. The filamentary coating covers the underlying surface with hard abrasion resistance material while also being compliant and capable of local accommodation to particle impacts. The coating can also function as thermal and/or acoustical insulation and has a friction reducing effect. 11 figs.
Hirschfeld, T.B.
Laboratory blast wave driven instabilities
This presentation discusses experiments well-scaled to the blast wave driven instabilities during the explosion phase of SN1987A. Blast waves occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 ?m plastic layer that is followed by a low density foam layer. A blast wave structure similar to those in supernovae, is created in the plastic layer. The blast wave crosses a perturbed interface, which produces nonlinear, unstable growth dominated by the Rayleigh-Taylor (RT) instability. Recent experiments have been performed using complex initial conditions featuring a three-dimensional interface structure with a wavelength of 71 ?m in two orthogonal directions, at times supplemented by an additional sinusoidal mode of 212 ?m or 424 ?m. We have detected the interface structure under these conditions, using dual orthogonal radiographs on some shots, and will show some of the resulting data. Recent advancements in our x-ray backlighting techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed. Current simulations do not show this phenomenon. This presentation will discuss the amount of mass in these spike extensions as well as the error analysis of this calculation. Future experiments will also be discussed. They will be focusing on realistic initial conditions based on 3D stellar evolution models. This research was sponsored by the Stewardship Science Academic Alliances Program through DOE Research Grants DE-FG52-07NA28058, DE-FG52-04NA00064, and other grants and contracts.
Kuranz, Carolyn
Self-modulating abrasive medium and its application to abrasive flow machining for finishing micro channel surfaces
This study developed a self-modulating abrasive medium whose viscosity and fluidity can be adjusted during the processing\\u000a period. The complex micro channel was fabricated on the stainless steel (SUS304) by using wire electrical discharge machining\\u000a (wire-EDM). An experiment of employing abrasive flow machining (AFM) was conducted to evaluate the characteristics of various\\u000a levels of roughness and finishing of the micro
Hsinn-Jyh Tzeng; Biing-Hwa Yan; Rong-Tzong Hsu; Yan-Cherng Lin
Determining dynamically active abrasive particles in the media used in centrifugal force assisted abrasive flow machining process
Abrasive flow machining (AFM) is a relatively new non-traditional process in which a semisolid media consisting of abrasive\\u000a particles and a flexible polymer carrier is extruded through or across the component to be machine finished. This process\\u000a is capable of providing excellent surface finishes on a wide range of simple as well as intricated shaped components. Low\\u000a material removal rate
R. S. Walia; H. S. Shan; P. Kumar
Effect of carbide degradation in a Ni-based hardfacing under abrasive and combined impact\\/abrasive conditions
Within this work, the effect of carbide degradation in a WC\\/W2C reinforced Ni-based hardfacing was assessed under abrasive and combined impact\\/abrasive conditions. In view of the above, a WC\\/W2C reinforced Ni-based hardfacing was deposited by plasma transferred arc (PTA) welding using different welding currents. Microstructure was characterised by quantitative metallography to determine specific structural parameters: mean carbide diameter and carbide
C. Katsich; E. Badisch
The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites.
This presentation discusses experiments involving the evolution of hydrodynamic instabilities in the laboratory under high-energy-density (HED) conditions. These instabilities are driven by blast waves, which occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. Instabilities evolving under HED conditions are relevant to astrophysics. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 ?m plastic layer that is followed by a low-density foam layer. A blast wave structure similar to those in supernovae is created in the plastic layer. The blast wave crosses an interface having a 2D or 3D sinusoidal structure that serves as a seed perturbation for hydrodynamic instabilities. This produces unstable growth dominated by the Rayleigh-Taylor (RT) instability in the nonlinear regime. We have detected the interface structure under these conditions using x-ray backlighting. Recent advances in our diagnostic techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed or predicted by current simulations. The observed effect is potentially of great importance as a source of mass transport to places not anticipated by current theory and simulation. I will discuss the amount of mass in these spike extensions, the associated uncertainties, and hypotheses regarding their origin We also plan to show comparisons of experiments using single mode and multimode as well as 2D and 3D initial conditions. This work is sponsored by DOE/NNSA Research Grants DE-FG52-07NA28058 (Stewardship Sciences Academic Alliances) and DE-FG52-04NA00064 (National Laser User Facility).
Blasting Injuries in Surface Mining with Emphasis on Flyrock and Blast Area Security.
Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgement or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preven...
D. K. Ingram G. L. Mowrey T. R. Rehak T. S. Bajpayee
Seismic vibrations in bulk blasting with high-precise electronic and nonelectric blasting systems at quarries
The authors report measurement data on seismic waves in bulk blasting at quarries by using new high-precise electronic and\\u000a pyrotechnic blasting systems. It is proved that both systems are efficient, intensity of seismic waves is much lower in large-scale\\u000a bulk blasting. The authors implemented numerical modeling of seismic wave propagation under a short-delay bulk blast at a\\u000a quarry. Influence of
E. N. Sher; A. G. Chernikov
Estimating Abrasivity of Rock by Laboratory and In Situ Tests
The degree to which a rock abrades another rock is called its "abrasivity". Laboratory tests of abrasivity can be broadly divided into four kinds: drilling, rubbing, turning-operation and tumbling tests. The present study was initiated 30 years ago with the objective of investigating and developing methods for measuring rock abrasivity, and making some contribution towards understanding the relationships between the above test methods. Within the range of tests conducted, the turning-operation test turned out to be superior to the drilling test, albeit slightly, in terms of practicality. We have also conducted in situ tests using rock drills for the last 20 years. The results of those tests have been investigated and compared with the results of laboratory tests. There is a large degree of scatter in the data on gauge loss in button bits, which has obscured any correlations with laboratory data. Some correlations were found between height loss in button bits and laboratory findings.
Okubo, S.; Fukui, K.; Nishimatsu, Y.
Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust
A protocol has been developed that produced the type of lunar soil abrasion damage observed on Apollo spacesuits. This protocol was then applied to four materials (Kevlar (DuPont), Vectran (Kuraray Co., Ltd.), Orthofabric, and Tyvek (DuPont)) that are candidates for advanced spacesuits. Three of the four new candidate fabrics (all but Vectran) were effective at keeping the dust from penetrating to layers beneath. In the cases of Kevlar and Orthofabric this was accomplished by the addition of a silicone layer. In the case of Tyvek, the paper structure was dense enough to block dust transport. The least abrasive damage was suffered by the Tyvek. This was thought to be due in large part to its non-woven paper structure. The woven structures were all abraded where the top of the weave was struck by the abrasive. Of these, the Orthofabric suffered the least wear, with both Vectran and Kevlar suffering considerably more extensive filament breakage.
Gaier, James R.; Meador, Mary Ann; Rogers, Kerry J.; Sheehy, Brennan H.
Prepolishing on a CNC platform with bound abrasive contour tools
Deterministic microgrinding (DMG) of optical glasses and ceramics is the commercial manufacturing process of choice to shape glass surfaces prior to final finishing. This process employs rigid bound matrix diamond tooling resulting in surface roughness values of 3-5?m peak to valley and 100-400nm rms, as well as mid-spatial frequency tool marks that require subsequent removal in secondary finishing steps. The ability to pre-polish optical surfaces within the grinding platform would reduce final finishing process times. Bound abrasive contour wheels containing cerium oxide, alumina or zirconia abrasives were constructed with an epoxy matrix. The effects of abrasive type, composition, and erosion promoters were examined for tool hardness (Shore D), and tested with commercial optical glasses in an Optipro CNC grinding platform. Metrology protocols were developed to examine tool wear and subsequent surface roughness. Work is directed to demonstrating effective material removal, improved surface roughness and cutter mark removal.
Schoeffler, Adrienne E.; Gregg, Leslie L.; Schoen, John M.; Fess, Edward M.; Hakiel, Michael; Jacobs, Stephen D.
Abrasion resistance of in situ Fe-TiC composites
Metal matrix composites containing a high volume fraction of carbide, nitride, boride, and/or oxide particles are frequently the materials of choice for applications which require high wear resistance. It is the very hard second phase particles which imbue the metal matrix composite with its superior wear resistance. For example, additions of titanium carbide (TiC), one of the hardest of the carbides with a Vickers hardness of 19.6--31.4 GPa, can be used to improve the abrasion resistance of iron alloys. In the present study in situ metal matrix composites, containing between 23 and 31 volume percent carbides, were produced from Fe-Ti-C and Fe-Cr-Ti-C melts, and their abrasion resistance was compared with that of unreinforced Fe and a white cast iron using a high-stress pin abrasion test.
Dogan, O.N.; Hawk, J.A. [Bureau of Mines, Albany, OR (United States). Albany Research Center] [Bureau of Mines, Albany, OR (United States). Albany Research Center
Decontamination of surfaces by blasting with crystals of H{sub 2}O and CO{sub 2}
A major mission of the US Department of Energy during the 1990s is site and environmental cleanup. In pursuit of this mission, numerous remediation projects are under way and many others are being planned at Oak Ridge National Laboratory (ORNL). In this report, tests using two proposed methods for decontaminating surfaces one using water ice crystals [Crystalline Ice Blast (CIB)], the other using dry ice crystals (CO{sub 2} Cleanblast{trademark}) -- are described. Both methods are adaptations of the commonly used sand blasting technology. The two methods tested differ from sand blasting in that the particles are not particularly abrasive and do not accumulate as particles in the wastes. They differ from each other in that the CO{sub 2} particles sublime during and after impact and the ice particles melt. Thus, the two demonstrations provide important information about two strong candidate decontamination methodologies. Each process was tested at ORNL using contaminated lead bricks and contaminated tools and equipment. Demonstrations with the prototype Crystalline Ice Blast and the CO{sub 2} Cleanblast systems showed that paint, grease, and oil can be removed from metal, plastic, asphalt, and concrete surfaces. Furthermore, removal of contamination from lead bricks was highly effective. Both processes were found to be less effective, under the conditions tested, with contaminated tools and equipment that had chemically bonded contamination or contamination located in crevices since neither technology abrades the substrates or penetrates deeply into crevices to remove particulates. Some process improvements are recommended.
Benson, C.E.; Parfitt, J.E.; Patton, B.D.
Procedure for calculating drilling and blasting parameters and experience of blasting in constrained material
Tight-face blasting is a production method which provides an improvement in drilling and blasting (DAB) indices and it involves the fact that the blasted volume over the breaking front is 'overloaded' by constrained material. The constraining material used is previously broken rock mass which has an acoustic stiffness several times less than the material being broken and a capacity to
N. I. Semenyakin; V. V. Arshavskii; A. S. Bykovtsev; V. N. Oparin; V. B. Vil'chinskii
Looking southwest at blast furnaces no. 5 and no. 6 ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Looking southwest at blast furnaces no. 5 and no. 6 with blast furnace trestle and Gondola Railroad cars in foreground. - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA
Looking southeast at blast furnaces no. 5 and no. 6 ...
Looking southeast at blast furnaces no. 5 and no. 6 with blast furnace trestle and Gondola Railroad cars in foreground. - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA
9. LOOKING NORTH AT TRESTLE, HOIST HOUSE No. 1, BLAST ...
9. LOOKING NORTH AT TRESTLE, HOIST HOUSE No. 1, BLAST FURNACE No. 1, AND HOT BLAST STOVES. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA
Looking east at blast furnace no. 5 between the hot ...
Looking east at blast furnace no. 5 between the hot blast stoves (left) and the dustcatcher (right). - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA
INTERIOR VIEW LOOKING WEST, CAST HOUSE OF BLAST FURNACE NO. 1 AND BLAST FURNACE NO. 2. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 1 & No. 2, Donner Avenue, Monessen, Westmoreland County, PA
GENERAL VIEW OF TURBO-BLOWER BUILDING (LEFT), BLAST FURNACE (CENTER), AND HOT BLAST STOVES (RIGHT). - Republic Iron & Steel Company, Youngstown Works, Haselton Blast Furnaces, West of Center Street Viaduct, along Mahoning River, Youngstown, Mahoning County, OH
30 CFR 75.1310 - Explosives and blasting equipment.
...2013-07-01 2013-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...
Factors in Selecting and Applying Commercial Explosives and Blasting Agents.
In the report commercial blasting compounds are classified according to their nitroglycerin (or equivalent explosive oil) and ammonium nitrate content as dynamites, gelatins, blasting agents, military explosives, and blasting accessories. The ingredients ...
R. A. Dick
30 CFR 75.1316 - Preparation before blasting.
...Tests shall be conducted using a blasting multimeter or other instrument...designed for such use. (3) The blasting cable or detonator circuitry...approaching each other, cutting, drilling and blasting shall be done at only one...
Experimental Measures of Blast and Acoustic Trauma in Marine Mammals.
Blast traumas are essentially mechanical responses, therefore blast effects are inducible and measurable in post-mortem specimens. To determine onset of damage zones for blast trauma in marine mammals, fresh post-mortem specimens were implanted with press...
D. R. Ketten
Coupled rock motion and gas flow modeling in blasting.
The spherical element computer code DMC (Distinct Motion Code) used to model rock motion resulting from blasting has been enhanced to allow routine computer simulations of bench blasting. The enhancements required for bench blast simulation include: (1) m...
D. S. Preece S. D. Knudsen
Tryckverkan i Slutna Volymer. (Blast Effects in Confined Volumes).
The report gives a brief presentation of blast effects in confined volumes. In particular, blast effects in naval structures are discussed. Examples of typical structural damages and simple methods for assessment of blast effects are given. Further on, me...
L. Fast
Field evidence of two-phase abrasion process
The rounded shape of river rocks is clear evidence that abrasion due to bed load transport is a significant agent for mass loss. Its contribution to downstream fining, however, is typically assumed to be negligible - as diminution trends may be explained solely by size-selective transport. A recent theory has predicted that pebble abrasion occurs in two well separated phases: in Phase 1, an intially-polyhedral pebble rounds to the shape of an inscribed ellipsoid without any change in axis dimensions; in Phase II, axis dimensions are slowly reduced. Importantly, Phase I abrasion means that an initially-blocky pebble may lose up to half its mass without any apparent change in 'size', which is only measured as the length of a single pebble axis by most field researchers. We hypothesize that field studies have significantly underestimated the importance of abrasion because they do not quantify pebble shape, and we set out to demonstrate that two-phase abrasion occurs in a natural stream. Our study examines downstream trends in pebble size and shape along a 10-km stretch of the Rio Mameyes within the Luquillo Critical Zone observatory, where volcaniclastic cobbles and boulders are transported by bed load at slopes up to 10%. The upper reaches of the stream consist of alluviated bedrock valleys that preclude sediment storage and thus minimize size-selective transport, which allows us to isolate the effects of abrasion. The lower 5 km is an alluvial river in which size-selective transport becomes operative. We quantified the shape and size of thousands of pebbles along the profile using hand and image-based techniques. The data provide the first field validation of two-phase abrasion; in the bedrock reaches, pebbles clearly evolve toward ellipsoids without any significant change in axis dimensions (rounding), while in the lower reaches pebbles slowly reduce their axis dimensions with little or no change in roundness. Results also show that shape metrics determined from two-dimensional (2D) imaging provide an adequate representation of the 3D evolution. In particular, the 2D curvature distribution is a sensitive metric of pebble shape, and is strongly related to the recently proposed 'equilibrium points' determined from 3D hand measurements. Although changes in pebble axis dimensions appear to be dominated by size-selective transport, shape data reveal that abrasion produces significant mass loss of pebbles. This mass loss affects both the mobility of the pebbles, and also produces substantial quantities of sand and silt that contribute to floodplain and ocean deposition downstream.
Miller, K. L.; Szabo, T.; Jerolmack, D. J.; Domokos, G.
Empirical methods to predict the abrasion resistance of rock aggregates
The possibility of predicting the Los Angeles (L.A.) abrasion loss from the Schmidt hammer, point load and porosity tests\\u000a was investigated using 9 igneous, 11 metamorphic and 15 sedimentary rocks with L.A. values ranging from 10 to 76%. Regression\\u000a analysis indicated a strong correlation (r\\u000a 2�=�0.72) between L.A. abrasion loss and point load and a good correlation (r\\u000a 2�=�0.62) between
Sair Kahraman; Osman Gunaydin
Polishing is made cheaper by disposable diamond-impregnated abrasive cloth
Diamond impregnated abrasive cloth eliminated expensive diamond pastes and was economically disposed of to avoid contamination. Cloth was spunbonded nylon, but any napless fabric could be used. Cloth was sprayed with diamond abrasive gel.
Harper, F. J.
Technique for abrasive cutting of thick-film conductors for hybrid circuits
Abrasive jet technique, producing prototype conductor networks for thick-film hybrid microcircuits, does not require screening and fixing procedures. Pantograph engraver is used to perform abrasive cutting of the conductor network.
Nugent, J. B.; Palermo, J. S.
Friability and crushing strength of micrometer-size diamond abrasives used in microgrinding of optical glass
In abrasive grinding, the properties of the abrasives and their response to impact loading play a significant role in determining the results achievable. For micrometer-size diamond abrasives used for bound-abrasive microgrinding of optical glass, friability testing is used to estimate the related particle properties. Friability and crushing strength of diamond abrasives are estimated based on the data from comminution of sample powders on a commercial SPEX mixer/mill. Different diamond abrasives as well as a CBN abrasive are tested. Evolution of powder size and size distribution with comminution time is characterized with a HORIBA laser scattering analyzer. Correlation is established for the impact stress and the probability of fracture during comminution. This study demonstrates how to combine the ease of data acquisition found in a conventional friability test with the capability of predicting specific mechanical properties normally found only by crushing individual abrasive particles.
Zhou, Yiyang; Takahashi, Toshio; Quesnel, David J.; Funkenbusch, Paul D.
Three-body abrasive wear of short glass fibre polyester composite
Short E-glass fibre-reinforced polyester composites with and without filler have been studied for the low stress abrasive wear behaviour carried out using Rubber Wheel Abrasion Test (RWAT) apparatus. In the present investigation, angular silica sand particles of size ranging between 100�200 and 200�300 ?m were used as dry and loose abrasives. The volume loss of the composite during three-body abrasion
Navin Chand; Ajay Naik; Somit Neogi
Two-body and three-body abrasive wear behaviour of polyaryletherketone composites
Single and multipass two-body and three-body abrasive wear behaviour of various polyaryletherketone composites have been carried out by using a pin-on-disc machine and a rubber wheel abrasion test (RWAT) rig. Abrasive wear studies were conducted under different loads and sliding distances. Comparative wear performance of all the composites at different loads shows that specific wear rate (Ko) of two-body abrasive
A. P. Harsha
Rodent model of direct cranial blast injury.
Traumatic brain injury resulting from an explosive blast is one of the most serious wounds suffered by warfighters, yet the effects of explosive blast overpressure directly impacting the head are poorly understood. We developed a rodent model of direct cranial blast injury (dcBI), in which a blast overpressure could be delivered exclusively to the head, precluding indirect brain injury via thoracic transmission of the blast wave. We constructed and validated a Cranium Only Blast Injury Apparatus (COBIA) to deliver blast overpressures generated by detonating .22 caliber cartridges of smokeless powder. Blast waveforms generated by COBIA replicated those recorded within armored vehicles penetrated by munitions. Lethal dcBI (LD(50) ? 515?kPa) was associated with: (1) apparent brainstem failure, characterized by immediate opisthotonus and apnea leading to cardiac arrest that could not be overcome by cardiopulmonary resuscitation; (2) widespread subarachnoid hemorrhages without cortical contusions or intracerebral or intraventricular hemorrhages; and (3) no pulmonary abnormalities. Sub-lethal dcBI was associated with: (1) apnea lasting up to 15?sec, with transient abnormalities in oxygen saturation; (2) very few delayed deaths; (3) subarachnoid hemorrhages, especially in the path of the blast wave; (4) abnormal immunolabeling for IgG, cleaved caspase-3, and ?-amyloid precursor protein (?-APP), and staining for Fluoro-Jade C, all in deep brain regions away from the subarachnoid hemorrhages, but in the path of the blast wave; and (5) abnormalities on the accelerating Rotarod that persisted for the 1 week period of observation. We conclude that exposure of the head alone to severe explosive blast predisposes to significant neurological dysfunction. PMID:21639724
Kuehn, Reed; Simard, Philippe F; Driscoll, Ian; Keledjian, Kaspar; Ivanova, Svetlana; Tosun, Cigdem; Williams, Alicia; Bochicchio, Grant; Gerzanich, Volodymyr; Simard, J Marc
Observation of 1-10 MeV Gamma-Rays from the Crab with the Balloon-Borne LXeGRIT Compton Telescope
Aprile, E.; Curioni, A.; Giboni, K.-L.; Kobayashi, M.; Oberlack, U. G.; Chupp, E. L.; Dunphy, P. P.; Ventura, S.; Doke, T.; Kikuchi, J.
30 CFR 816.66 - Use of explosives: Blasting signs, warnings, and access control.
...Blasting signs, warnings, and access control. 816.66 Section 816.66...Blasting signs, warnings, and access control. (a) Blasting signs. Blasting...the blasting schedule. (c) Access control. Access within the...
Direct current magnetic abrasive finishing process provides hardly any stirring effect on static flexible magnetic abrasive brush (S-FMAB). Continuous use of S-FMAB and absence of stirring leads to dullness of abrasive cutting edges resulting in low finishing rate. To overcome this weakness of the process, the FMAB has been made pulsating using pulse direct current (DC) power supply. Empirical models
V. K. Jain; D. K. Singh; V. Raghuram
Prediction system of magnetic abrasive finishing (MAF) on the internal surface of cylindrical tube
This study mainly used the way of the magnetic abrasive finishing (MAF) to explore the cylindrical tube of stainless steel SUS304 related to the processing characteristic and the prediction system. The self-make adjustable electricity polishing mechanism was assembled on the magnetic abrasive machine. The magnetic abrasive which was consisted of the sintered iron and Aluminum Oxide powder filled in the
Ching-Lien Hung; Wei-Liang Ku; Lieh-Dai Yang; Han-Ming Chow
Shore platform abrasion in a para-periglacial environment, Galicia, northwestern Spain
The Schmidt Rock Test Hammer was used to study the effect of abrasion on shore platforms in Galicia, northwestern Spain. On platforms where tidally-induced weathering (salt, wetting and drying, etc.) is dominant, rock strength is significantly lower than in areas where abrasion is, or has been active in the recent past. This suggests that abrasion removes weathered surface material, exposing
R. Blanco-Chao; A. P�rez-Alberti; A. S. Trenhaile; M. Costa-Casais; M. Valc�rcel-D�az
Method for the characterization of the abrasion induced nanoparticle release into air from surface coatings
A novel method for the quantification of the nanoparticle release into air from surface coatings was developed. The method is based on the combination of a defined abrasion process with highly sensitive methods to quantify airborne particle concentration. A standardized system for abrasion testing was employed to adjust a defined wear process.Details of the abrasion system are presented in combination
Manuel Vorbau; Lars Hillemann; Michael Stintz
Glacial erosion and bedrock properties in NW Scotland: Abrasion and plucking, hardness and joint spacing
Subglacial erosion beneath glaciers occurs predominantly by abrasion and plucking, producing distinct erosional forms. The controls on the relative importance of abrasion vs. plucking are poorly understood. On the one hand, glacial conditions that favour or suppress cavity formation (ice velocity, ice thickness, and water pressure) are thought to favour plucking or abrasion, respectively. Conversely, bedrock properties are also known
Maarten Krabbendam; Neil F. Glasser
Improving the abrasion resistance of hydraulic-concrete containing surface crack by adding silica fume
Abrasion damage generally results from constant friction and impact of waterborne silt, sand, gravel, rocks, ice, and other debris on concrete surfaces during the operation of a hydraulic structure. In this study, a waterborne abrasion over a large area of the test slab was developed to investigate the influence of surface cracks on the abrasion�erosion resistance of concretes, with variable
Yu-Wen Liu
Dynamic elastic�plastic analysis of 3D deformation in abrasive waterjet machining
Although several theoretical and experimental models have been developed for abrasive waterjet machining (AWJM), the exact nature of erosion is not yet understood. This paper presents an attempt to model AWJM using the finite element method (FEM) in order to explain the abrasive particle�workpiece interaction process. Also, the model predicts the depth of deformation as a result of abrasive particle
A. I Hassan; J Kosmol
Fixed abrasive diamond wire machining�part I: process monitoring and wire tension force
The process monitoring and mechanics of fixed abrasive diamond wire saw machining are investigated in this study. New techniques to affix diamond particles to a steel wire core have advanced to make this process feasible for the machining of ceramics, wood, and foam materials. Developments in fixed abrasive diamond wire machining are first reviewed. Advantages of using fixed abrasive diamond
W. I. Clark; A. J. Shih; C. W. Hardin; R. L. Lemaster; S. B. McSpadden
Design and development of the magnetorheological abrasive flow finishing (MRAFF) process
A new precision finishing process for complex internal geometries using smart magnetorheological polishing fluid is developed. Magnetorheological abrasive flow finishing (MRAFF) process provides better control over rheological properties of abrasive laden magnetorheological finishing medium. Magnetorheological (MR) polishing fluid comprises of carbonyl iron powder and silicon carbide abrasives dispersed in the viscoplastic base of grease and mineral oil; it exhibits change
Sunil Jha; V. K. Jain
Parametric Optimization of Centrifugal Force-Assisted Abrasive Flow Machining (CFAAFM) by the Taguchi Method
Extrusion honing, known as abrasive flow machining (AFM), deburrs, polishes, and radiuses surfaces and edges by flowing an abrasive-laden media over these areas. The process is particularly used on internal shapes that are difficult to process by other nonconventional machining processes. Because abrasive action occurs only in areas where the flow is restricted, tooling is used to direct the media
R. S. Walia; H. S. Shan; Pradeep Kumar
Computer simulation of developing abrasive jet machined profiles including particle interference
A novel and generally applicable computer simulation was developed to predict the time evolution of the eroded profiles of air abrasive jet machined surfaces, as a function of process parameters such as: abrasive nozzle size, inclination and distance to target surface, abrasive jet particle velocity, size and flux distribution. The effect of collisions between incoming and rebounding particles was included
N. Shafiei; H. Getu; A. Sadeghian; M. Papini
This article presents a set of studies performed on aluminum-silicon carbide particulate metal matrix composites prepared by adding 5, 10, 15 and 20% of SiC in aluminum alloy and processed with abrasive water jets that are formed with garnet and silicon carbide abrasives of 80 mesh size. These studies are essentially meant to assess the penetration ability of abrasive water
S. Srinivas; N. Ramesh Babu
Grooving micro-abrasion of polyamide 11 coated carbon steel tubulars for downhole application
The tribological properties of polyamide 11 coated carbon steel injector tubulars are reported using a commercially available micro-abrasion tester, as a candidate method for assessing the abrasive wear of polymer coatings. Efforts have been made to reproduce the wear mechanisms found to predominate in field simulated conditions. The wireline-based tests produced severe grooving abrasion of the polyamide 11 coating resulting
J. O Bello; R. J. K Wood
Explosive signatures: Pre & post blast
Manuscripts 1 and 2 of this dissertation both involve the pre-blast detection of trace explosive material. The first manuscript explores the analysis of human hair as an indicator of exposure to explosives. Field analysis of hair for trace explosives is quick and non-invasive, and could prove to be a powerful linkage to physical evidence in the form of bulk explosive material. Individuals tested were involved in studies which required handling or close proximity to bulk high explosives such as TNT, PETN, and RDX. The second manuscript reports the results of research in the design and application of canine training aids for non-traditional, peroxide-based explosives. Organic peroxides such as triacetonetriperoxide (TATP) and hexamethylenetriperoxidediamine (HMTD) can be synthesized relatively easily with store-bought ingredients and have become popular improvised explosives with many terrorist groups. Due to the hazards of handling such sensitive compounds, this research established methods for preparing training aids which contained safe quantities of TATP and HMTD for use in imprinting canines with their characteristic odor. Manuscripts 3 and 4 of this dissertation focus on research conducted to characterize pipe bombs during and after an explosion (post-blast). Pipe bombs represent a large percentage of domestic devices encountered by law enforcement. The current project has involved the preparation and controlled explosion of over 90 pipe bombs of different configurations in order to obtain data on fragmentation patterns, fragment velocity, blast overpressure, and fragmentation distance. Physical data recorded from the collected fragments, such as mass, size, and thickness, was correlated with the relative power of the initial device. Manuscript 4 explores the microstructural analysis of select pipe bomb fragments. Shock-loading of the pipe steel led to plastic deformation and work hardening in the steel grain structure as evidenced by optical microscopy and microhardness testing respectively.
Bernier, Evan Thomas
Anorectal injury in pelvic blast.
The signature injury of the Afghanistan campaign has, amongst other things, included an increased incidence of destructive anorectal injury. There is no significant body of evidence about this type of injury on which to base management strategies. This review examines the historical military data, later civilian reports, many of which have challenged the military dogmas of Vietnam, and the spartan contemporaneous military data which does not particularly address pelviperineal blast injury. There is no evidence to support a move away from the doctrine of the four D's (diversion, distal washout, drainage and direct repair), but sound surgical judgement remains the mainstay of managing these challenging and highly morbid injuries. PMID:23631323
Brogden, Tom G; Garner, J P
Zinc recovery from blast furnace flue dust
Blast furnace flue dusts are a mixture of oxides expelled from the top of the blast furnace, whose major components are iron oxides. They also contain zinc, silicon, magnesium and other minor element oxides in lesser amounts. The direct recycling of flue dust is not usually possible since it contains some undesirable elements (zinc and alkaline metals) that can cause
B. Asadi Zeydabadi; D. Mowla; M. H. Shariat; J. Fathi Kalajahi
Blast furnace coal injection in China
The development of blast furnace coal injection in China will be summarized. The improvements in the technical process for pneumatic conveying, injection feed control, distribution and combustion of pulverized coal will be covered. Ideas are also described concerning the use of oxy-coal technology in a blast furnace.
Zhou, J.G. (Ministry of Metallurgical Industry, Beijing (China). Central Iron and Steel Research Inst.)
30 CFR 75.1323 - Blasting circuits.
... (h) Uninsulated connections in each blasting circuit shall be kept out of water and shall not contact the coal, roof, ribs, or floor. (i) When 20 or fewer boreholes are fired in a round, the blasting circuit shall be wired in a single...
Shock sensitivity of blasting explosive cartridges
The undersand variable gap�initiator test was applied to most Japanese blasting explosive cartridges and found useful as the sensitivity test for the cartridges. The recent Japanese watergel and emulsion explosives were shown to be more shock�sensitive than previous ones. The blast noise in the undersand explosion was shown to decrease when the depth of sand cover the cartridge was increased.
Yuji Wada; Hideo Yabashi; Masamitsu Tamura; Tadao Yoshida; Toshio Matsuzawa; Fumio Hosoya
This paper describes methods for designing and implementing protective technologies for improving the blast and impact resistance of buildings. A protection plan for buildings may include designing blast-resistant columns, walls, and windows; other elements of security may also play a major part, including physical security measures such as: anti-ram barriers and fencing to demarcate a protective perimeter; features such as
J. E. Crawford
Color changing photonic crystals detect blast exposure.
Blast-induced traumatic brain injury (bTBI) is the "signature wound" of the current wars in Iraq and Afghanistan. However, with no objective information of relative blast exposure, warfighters with bTBI may not receive appropriate medical care and are at risk of being returned to the battlefield. Accordingly, we have created a colorimetric blast injury dosimeter (BID) that exploits material failure of photonic crystals to detect blast exposure. Appearing like a colored sticker, the BID is fabricated in photosensitive polymers via multi-beam interference lithography. Although very stable in the presence of heat, cold or physical impact, sculpted micro- and nano-structures of the BID are physically altered in a precise manner by blast exposure, resulting in color changes that correspond with blast intensity. This approach offers a lightweight, power-free sensor that can be readily interpreted by the naked eye. Importantly, with future refinement this technology may be deployed to identify soldiers exposed to blast at levels suggested to be supra-threshold for non-impact blast-induced mild TBI. PMID:21040795
Cullen, D Kacy; Xu, Yongan; Reneer, Dexter V; Browne, Kevin D; Geddes, James W; Yang, Shu; Smith, Douglas H
Spraengning mot Kompakterat Berg (Confined Volume Blasting),
SveDeFo has performed halfscale tests with confined volume blasting in LKAB:s mine in Malmberget in order to find out if that gives an improvement in fragmentation. The answer is yes. The fragmentation is better in confined volume blasting compared to ord...
M. Olsson
Copper staves in the blast furnace
Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that
R. G. Helenbrook; W. Kowalski; K. H. Grosspietsch; H. Hille
Highly concentrated foam formulation for blast mitigation
A highly concentrated foam formulation for blast suppression and dispersion mitigation for use in responding to a terrorism incident involving a radiological dispersion device. The foam formulation is more concentrated and more stable than the current blast suppression foam (AFC-380), which reduces the logistics burden on the user.
Tucker, Mark D. (Albuquerque, NM) [Albuquerque, NM; Gao, Huizhen (Albuquerque, NM) [Albuquerque, NM
Building BLAST for Coprocessor Accelerators Using Macah
Abstract The problem of detecting similarities between different genetic sequences is fun- damental to many,research pursuits in biology and genetics. BLAST (Basic Local Alignment and Search Tool) is the most commonly,used tool for identi- fying and assessing the significance of such similarities. With the quantity of available genetic sequence data rapidly increasing, improving the performance of the BLAST algorithm is
Ben Weintraub
A nonmineralized approach to abrasion-resistant biomaterials.
The tooth-like mouthparts of some animals consist of biomacromolecular scaffolds with few mineral components, making them intriguing paradigms of biostructural materials. In this study, the abrasion resistance of the jaws of one such animal, the bloodworm Glycera dibranchiata, has been evaluated by nanoindentation, nanoscratching, and wear testing. The hardest, stiffest, and most abrasion-resistant materials are found within a thin (<3 microm) surface layer near the jaw tip and a thicker (10-20 microm) subsurface layer, both rich in unmineralized Cu. These results are consistent with the supposition that Cu ions are involved in the formation of intermolecular coordination complexes between proteins, creating a highly cross-linked molecular network. The intervening layer contains aligned atacamite [Cu(2)(OH)(3)Cl] fibers and exhibits hardness and stiffness (transverse to the alignment direction) that are only slightly higher than those of the bulk material but lower than those of the two Cu-rich layers. Furthermore, the atacamite-containing layer is the least abrasion-resistant, by a factor of approximately 3, even relative to the bulk material. These observations are broadly consistent with the behavior of engineering polymer composites with hard fiber or particulate reinforcements. The alignment of fibers parallel to the jaw surface, and the fiber proximity to the surface, are both suggestive of a natural adaptation to enhance bending stiffness and strength rather than to endow the surface regions with enhanced abrasion resistance. PMID:17702868
Pontin, Michael G; Moses, Dana N; Waite, J Herbert; Zok, Frank W
About Abrasive Properties of Steel Erosion Products During Electrospark Processing.
An investigation was made of abrasive properties of metal powders, obtained by the electro-spark method. Investigated were steels 40KH, 2KH13, R18, and alloy T15K6, as well as boron and silicon carbides. Dispersion of these materials took place in kerosen...
N. V. Afanasev A. G. Goloveiko
A useful evacuation aid for intraoral air-abrasive devices.
Air-abrasive technology offers several advantages over conventional handpieces. Although modern high-speed evacuation systems result in limited powder accumulation, the microabrasive debris continues to be a major concern. This article highlights the need for rubber dam isolation and introduces a makeshift evacuation device fabricated from a plastic soft drink container. PMID:10332363
Liebenberg, W H
Iatrogenic tooth abrasion comparisons among composite materials and finishing techniques
Statement of Problem. Many different rotary instruments are available for shaping composite restorations. Whether use of these instruments causes undesirable iatrogenic abrasion of either the tooth surface or the composite restorative material is unknown. Assuming that damage occurs, which technique is least damaging is unknown. Purpose. This in vitro study quantified the loss of surface enamel and dentin surrounding Class
Christina A. Mitchell; Maria R. Pintado; William H. Douglas
Sliding and abrasive wear behaviour of boride coatings
Polyphase boride coatings constituted by an inner layer of Fe2B and an outer layer of FeB were thermochemically grown on iron and medium carbon steel by a pack cementation process. The tribological behaviour of borided samples was investigated under both sliding and abrasion testing conditions. Considerably different values of wear rate were found in different regions of the coatings. The
C. Martini; G. Palombarini; G. Poli; D. Prandstraller
An erosion model of polycrystalline ceramics in abrasive waterjet cutting
This paper investigates the erosion phenomenon associated with abrasive waterjet cutting of polycrystalline ceramics. The erosion mechanisms observed in this study include intergranular network cracking and plastic flow. Material removal due to network cracking is calculated with a crack network model which relates the fracture surface energy in forming the crack network to the energy of the impact induced stress
Jiyue Zeng; Thomas J Kim
Kerf characteristics in abrasive waterjet cutting of ceramic materials
An abrasive water jet (AWJ) can provide a more effective means for precision cutting of ceramic materials as compared with conventional machining methods, but many aspects about this cutting technology are still under flux and development. In this study, experimental techniques based on statistical experimental design principles and theoretical investigations were conducted to study AWJ cutting of alumina-based ceramics. Semi-empirical
L. Chen; E. Siores; W. C. K. Wong
Enhancing Abrasive Waterjet Cutting of Ceramics by Head Oscillation Techniques
Abrasive Water Jet (AWJ) cutting technology can provide very effective means for shape cutting of ceramics, but the slow cutting speed needs to be improved without compromising cutting quality. In this paper, experimental techniques based on statistical design principles and theoretical investigations were conducted to optimise and predict the AWJ cutting process applicable to ceramics. The new cutting head oscillation
E. Siores; W. C. K. Wong; L. Chen; J. G. Wager
Innovative decontamination technology by abrasion in vibratory vessels
Available in abstract form only. Full text of publication follows: The possibility of using conventional vibratory vessel technology as a decontamination technique is the motivation for the development of this project. The objective is to explore the feasibility of applying the vibratory vessel technology for decontamination of radioactively-contaminated materials such as pipes and metal structures. The research and development of this technology was granted by the U.S. Department of Energy (DOE). Abrasion processes in vibratory vessels are widely used in the manufacture of metals, ceramics, and plastics. Samples to be treated, solid abrasive media and liquid media are set up into a vessel. Erosion results from the repeated impact of the abrasive particles on the surface of the body being treated. A liquid media, generally detergents or surfactants aid the abrasive action. The amount of material removed increases with the time of treatment. The design and construction of the machine were provided by Vibro, Argentina private company. Tests with radioactively-contaminated aluminum tubes and a stainless steel bar, were performed at laboratory level. Tests showed that it is possible to clean both the external and the internal surface of contaminated tubes. Results show a decontamination factor around 10 after the first 30 minutes of the cleaning time. (authors)
Fabbri, Silvio; Ilarri, Sergio [National Atomic Energy Commission - CNEA, Avda. del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)
Abrasion of Concrete by Ice in Arctic Sea Structures.
In arctic sea regions a concrete sea structure is subjected to heavy mechanical loads near the water level due to the moving ice sheets. The determination of the abrasion depth is based on laboratory tests for measuring ice pressures against protruding ag...
S. Huovinen
Small blocks of sandstone were eroded by sliding under ice in a harmonic and a constant motion. The harmonic motion caused ice accretion on the rock and an ice\\/ice sliding surface. Addition of a dense layer of sand grains to the ice produced rock abrasion. Sliding of a cylinder of sandstone with constant angular velocity under ice eroded a pit
Stochastic simulation of active grain density in abrasive flow machining
Abrasive flow machining can be applied to an impressive range of finishing operations economically and effectively. Both theoretical and experimental studies of the media topography are greatly hampered by the inherent random nature and the multiplicity of variables. A stochastic simulation model has been developed to determine the active grain density on the media surface which is in contact with
Rajendra K. Jain; V. K. Jain
Modelling of Abrasive Waterjet Machining: A New Approach
Abrasive waterjet (AWJ) machining is one of the recent non-traditional methods starting to be used widely in industry for material removal of different materials. The cutting performance of AWJ is achieved by a very high speed, small-scale erosion process. In this paper, a modified form of Finnie's model for erosion is developed for application to AWJ. This modified form is
M. EITobgy; E. G. Ng; M. A. Elbestawi
Forces prediction during material deformation in abrasive flow machining
To study the finishing mechanism of abrasive flow machining (AFM), theoretical model of forces acting on a single grain has been developed. An experimental research has been carried out by measuring the axial force, radial force and active grain density during the AFM process. Results obtained from theoretical model for grain�workpiece interaction during material deformation have been compared with the
V. K. Gorana; V. K. Jain; G. K. Lal
A neural network process model for abrasive flow machining operations
This paper describes the development of a predictive process modeling system for the abrasive flow machining (AFM) process. This process is used for polishing and surface removal of workpieces with an internal flow path. The core of the process modeling system is a set of neural network models that predicts surface finish and dimensional change. These neural network models are
Kimberly L. Petri; Richard E. Billo; Bopaya Bidanda
Prediction of surface roughness during abrasive flow machining
An analytical model is proposed to simulate and predict the surface roughness for different machining conditions in abrasive flow machining (AFM). The kinematic analysis is used to model the interaction between grain and workpiece. Fundamental AFM parameters, such as the grain size, grain concentration, active grain density, grain spacing, forces on the grain, initial topography, and initial surface finish (R
Investigations into abrasive flow finishing of complex workpieces using FEM
Abrasive flow machining (AFM) process provides a high level of surface finish and close tolerances with an economically acceptable rate of surface generation for a wide range of industrial components. It is attempted to analyze the AFM process using finite element method (FEM) for finishing of external surfaces. To study the material removal mechanism of AFM, finite element model of
V. K. Jain; Rajani Kumar; P. M. Dixit; Ajay Sidpara
Direct laser fabrication of superalloy cermet abrasive turbine blade tips
This paper presents the development of a new technique for the production of abrasive turbine blade tips by direct laser processing. This superalloy cermet component is an integral part of the low-pressure turbine sealing system in a demonstrator engine. Direct laser fabrication of this component from a bed of loose powder results in significant cost savings and improved performance over
Suman Das; Timothy P. Fuesting; Gregory Danyo; Lawrence E. Brown; Joseph J. Beaman; David L. Bourell
Studies of Abrasive Wear in a Modified Impact Testing Machine.
Single tip abrasive wear was simulated in a conventional impact test machine modified by attaching a cemented carbide tip radially to the hammer. The swinging hammer produced a groove in the horizontal surface of low carbon steel of specimens, supported b...
U. Bryggman S. Hogmark O. Vingsbo
Resistance to abrasive wear of boron-based diffusion coatings
The diffusion saturation of components with boron and with boron in combination with other e lements increases their resistance to wear in an abrasive environment, leading to ever increasing use of the method in industry. However, the boronizing technology used in practice has substantial disadvantages: the boride surface layer produced is thin and extremely brittle. This makes it difficult to
K. P. Tabinskii; V. V. Kozub; M. V. Lizanets
Abrasion resistant active braze alloys for metal single layer technology
The technology of brazing a single layer of abrasive on to the surface of a grinding tool, metal single layer (MSL) technology, provides an alternative way to make use of the superabrasives diamond and cubic boron nitride in machining ceramic materials or super- alloys, cutting of construction materials, etc. For cer- tain applications of MSL bonded wheels, the grinding or
The effect of microstructure on abrasive wear of hardfacing alloys
Hardfacing is one of the most useful and economical ways to improve the performance of components submitted to severe wear conditions. A study was made to compare the microstructure and abrasion resistance of hardfacing alloys reinforced with primary chromium carbides, complex carbides or tungsten carbides. The hardfacing alloys were deposited onto ASTM A36 carbon steel plates by a shielded metal
M. F. Buchely; J. C. Gutierrez; L. M. Le�n; A. Toro
Mineral phases of green liquor dregs, slaker grits, lime mud and wood ash of a Kraft pulp and paper mill.
Four residues generated in a Kraft, pulp and paper plant, were characterized by X-ray fluorescence spectroscopy (XFA), powder X-ray diffraction (XRD), thermogravimmetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR). A quantitative phase composition model, that accounts for the observed data and for the physico-chemical conditions of formation, was postulated for each material. Emphasis was given on the identification of the mineral components of each material. The green liquor dregs and the lime mud contain Calcite and Gipsite. The slaker grits contains Calcite, Portlandite, Pirssonite, Larnite and Brucite. The Calcite phase, present in the dregs and in the lime mud, has small amounts of magnesium replacing calcium. The wood ash contains Quartz as the major crystalline mineral phase. PMID:17316983
Martins, Fernanda Machado; Martins, Joaniel Munhoz; Ferracin, Luiz Carlos; da Cunha, Carlos Jorge
Red imported fire ant (Hymenoptera: Formicidae) control with a corn grit bait of fenoxycarb without soybean oil.
The standard fenoxycarb fire ant bait formulation (Logic), composed of pregel defatted corn grits and soybean oil toxicant, was modified by eliminating the soybean oil. This formulation without soybean oil contained greater than 2 times more fenoxycarb and was as effective as the standard bait formulation against laboratory colonies of red imported fire ant, Solenopsis invicta Buren. In field tests, the modified and standard baits were equally effective in controlling fire ants after 6, 12, and 18 wk. Individual worker ants obtained from plots treated with fenoxycarb baits without soybean oil had greater than 47 times less fenoxycarb than did workers from the plots treated with the standard fenoxycarb baits containing soybean oil. PMID:1885843
Williams, D F; Banks, W A; Vander Meer, R K; Lofgren, C S
Brushing abrasion of luting cements under neutral and acidic conditions.
Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion. PMID:11203860
Buchalla, W; Attin, T; Hellwig, E
Dynamic fragmentation of blast mitigants
Experimental evidence from a wide range of sources shows that the expanding cloud of explosively disseminated material comprises �particles� or fragments which have different dimensions from those associated with the original material. Powders and liquids have often been used to surround explosives to act as blast mitigants, and this is the main driver for our research. There are also many other areas of interest where an initially intact material surrounding an explosive charge is dynamically fragmented into a distribution of fragment sizes. Examples of such areas include fuel air explosives and enhanced blast explosives as well as quasi-static pressure mitigation systems, and our studies are thus also relevant to these applications. In this paper, we consider the processes occurring as an explosive interacts with a surrounding layer of liquid or powder and identify why it is important to model these processes as a multiphase material problem as opposed to a single phase, single material velocity problem. We shall present results from this class of numerical modelling. In this paper we shall explore what determines the particle or fragment size distribution resulting from explosive dissemination of a layer of material and discuss reasons why clouds from disseminated liquids and powders look similar. We shall support our analysis with results from recent explosives trials and introduce early results from some ongoing small scale explosive mitigation experiments.
Milne, A. M.; Parrish, C.; Worland, I.
Two-body abrasion of a cast Al�Cu (2014 Al) alloy�Al 2O 3 particle composite: influence of heat treatment and abrasion test parameters
An Al�Cu (2014 Al) alloy reinforced with 10vol.% Al2O3 particles (size: 75�150?m), prepared by liquid metallurgy route, has been investigated under two-body (high stress) abrasive wear condition. The influence of varying load, abrasive size and sliding distance on the abrasive wear behaviour of the specimens was also studied. The base alloy prepared under similar condition has also been studied under
O. P. Modi
Study on the characteristics of Magneto-Electrolytic-Abrasive Polishing by using the newly developed nonwoven-abrasive pads
Recently, advanced technologies in general industry demand that the production of precision parts is much more precise and efficient. However, most of the precision finishing technologies cannot satisfy both the finishing efficiency and surface finishing at the same time. Magneto-Electrolytic-Abrasive Polishing (MEAP) is a new ultra precision machining technology, which combined many kinds of energy, has been deeply investigated under
Jeong-Du Kim; Yan-Meng Xu; Youn-Hee Kang
Solid Lubrication Fundamentals and Applications. Chapter 5; Abrasion: Plowing and Cutting
Chapter 5 discusses abrasion, a common wear phenomenon of great economic importance. It has been estimated that 50% of the wear encountered in industry is due to abrasion. Also, it is the mechanism involved in the finishing of many surfaces. Experiments are described to help in understanding the complex abrasion process and in predicting friction and wear behavior in plowing and/or cutting. These experimental modelings and measurements used a single spherical pin (asperity) and a single wedge pin (asperity). Other two-body and three-body abrasion studies used hard abrasive particles.
Miyoshi, Kazuhisa
Preparation of alumina/silica core-shell abrasives and their CMP behavior
Abrasive is one of key influencing factors on the surface quality during the chemical mechanic polishing (CMP). ?-Alumina particles, as a kind of widely used abrasive in CMP slurries, often cause to surface defects because of its high hardness. In the present paper, a series of novel alumina/silica core-shell abrasives in slurries were described. The CMP performances of the alumina/silica core-shell abrasives on hard disk substrate were investigated by using a SPEEDFAM-16B-4M CMP equipment. Experimental results indicate that the CMP performances are strong dependent on the coated SiO 2 content of the alumina/silica composite abrasives. Slurries containing the alumina/silica composite abrasives exhibited lower surface roughness and waviness as well as lower topographical variations and less scratch than that containing pure alumina abrasive under the same testing conditions.
Lei, Hong; Zhang, Pengzhen
Abrasive Wear Study of Rare Earth Modified Coatings by Statistical Method
This paper describes the effect of combined addition of rare earth elements namely CeO2 and La2O3 in Ni-base alloy coatings. The rare earth addition refines microstructure, increases hardness, and abrasive wear resistance of coatings. The abrasive wear behavior of these coatings was investigated using four factors load ( L), abrasive size ( A), sliding speed ( S), and temperature ( T) with three levels of each factor using RSM. ANOVA was carried out to determine the significant factors and interactions. Investigation showed that the load, abrasive size, and sliding speed were the main significant factors while load and abrasive size, load and sliding speed, abrasive size and sliding speed were the main significant interactions. Thus, an abrasive wear model was developed in terms of significant factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different conditions. A comparison of modeled and experimental results showed 3-8% error.
Acceleration of Ungapped Extension in Mercury BLAST
The amount of biosequence data being produced each year is growing exponentially. Extracting useful information from this massive amount of data efficiently is becoming an increasingly difficult task. There are many available software tools that molecular biologists use for comparing genomic data. This paper focuses on accelerating the most widely used such tool, BLAST. Mercury BLAST takes a streaming approach to the BLAST computation by off loading the performance-critical sections to specialized hardware. This hardware is then used in combination with the processor of the host system to deliver BLAST results in a fraction of the time of the general-purpose processor alone. This paper presents the design of the ungapped extension stage of Mercury BLAST. The architecture of the ungapped extension stage is described along with the context of this stage within the Mercury BLAST system. The design is compact and runs at 100 MHz on available FPGAs, making it an effective and powerful component for accelerating biosequence comparisons. The performance of this stage is 25� that of the standard software distribution, yielding close to 50� performance improvement on the complete BLAST application. The sensitivity is essentially equivalent to that of the standard distribution.
Buhler, Jeremy; Chamberlain, Roger D.
Blast investigation by fast multispectral radiometric analysis
Knowledge regarding the processes involved in blasts and detonations is required in various applications, e.g. missile interception, blasts of high-explosive materials, final ballistics and IED identification. Blasts release large amount of energy in short time duration. Some part of this energy is released as intense radiation in the optical spectral bands. This paper proposes to measure the blast radiation by a fast multispectral radiometer. The measurement is made, simultaneously, in appropriately chosen spectral bands. These spectral bands provide extensive information on the physical and chemical processes that govern the blast through the time-dependence of the molecular and aerosol contributions to the detonation products. Multi-spectral blast measurements are performed in the visible, SWIR and MWIR spectral bands. Analysis of the cross-correlation between the measured multi-spectral signals gives the time dependence of the temperature, aerosol and gas composition of the blast. Farther analysis of the development of these quantities in time may indicate on the order of the detonation and amount and type of explosive materials. Examples of analysis of measured explosions are presented to demonstrate the power of the suggested fast multispectral radiometric analysis approach.
Devir, A. D.; Bushlin, Y.; Mendelewicz, I.; Lessin, A. B.; Engel, M.
LTC vacuum blasting machine (concrete): Baseline report
The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure during maintenance activities was minimal, but due to mechanical difficulties dust monitoring could not be conducted during operation. Noise exposure was significant. Further testing for each of these exposures is recommended because of the outdoor environment where the testing demonstration took place. This may cause the results to be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed environment. In addition, other safety and health issues found were ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, and arm-hand vibration.
Abrasion in pyroclastic density currents: Insights from tumbling experiments
During granular mass movements of any kind, particles may interact with one another. The degree of interaction is a function of several variables including; grain-size distribution, particle concentration, density stratification and degree of fluidisation. The impact of particle interaction is additionally influenced by the relative speed, impact angle and clast temperature. Thus, both source conditions and transport-related processes are expected to influence the flow dynamics of pyroclastic density currents and their subsequent deposition. Here, we use tumbling experiments to shed light on the susceptibility of porous clasts to abrasion. We investigated the abrasion of unaltered volcanic rocks (5.7-80 vol.% porosity) from Unzen (Japan), Bezymianny (Russia) and Santorini (Greece) volcanoes as well as one synthetic analogue material, an insulating material with the trade name Foamglas� (95 vol.% porosity). Each experiment started with angular fragments generated in a jaw crusher from larger clasts. Two experimental series were performed; on samples with narrow and broader grain-size distributions, respectively. The dry samples were subject to rotational movement at constant speed and ambient temperature in a gum rotational tumbler for durations of 15, 30, 45, 60 and 120 min. The amount of volcanic ash (particles <2 mm) generated was evaluated as a function of experimental duration and sample porosity. We term �abrasion� as the ash fraction generated during the experiments. The observed increase of �abrasion� with increasing sample porosity and experimental duration is initially non-linear but becomes linear for experiments of 30 min duration or longer. For any given sample, abrasion appears to be more effective for coarser samples and larger initial mass. The observed range of ash generated in our experiments is between 1 and 35 wt.%. We find that this amount generally increases with increasing initial clast size or increasing breadth of the initial grain-size distribution. Despite the limits in the complexity that is experimentally attainable in this simulation of ash generation, our results clearly testify the rapid and efficient generation of ash by abrasion, strongly influenced by the material properties (e.g., crystallinity, pore textures).
Kueppers, Ulrich; Putz, Constanze; Spieler, Oliver; Dingwell, Donald B.
On the Propagation and Interaction of Spherical Blast Waves
The characteristics and the scaling laws of isolated spherical blast waves have been briefly reviewed. Both self-similar solutions and numerical solutions of isolated blast waves are discussed. Blast profiles in the near-field (strong shock region) and the far-field (weak shock region) are examined. Particular attention is directed at the blast overpressure and shock propagating speed. Consideration is also given to the interaction of spherical blast waves. Test data for the propagation and interaction of spherical blast waves emanating from explosives placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure.
Kandula, Max; Freeman, Robert
When decommissioning nuclear installations, large quantities of metal components are produced as well as significant amounts of other radioactive materials, which mostly show low surface contamination. Having been used or having been brought for a while in a controlled area marks them as 'suspected material'. In view of the very high costs for radioactive waste processing and disposal, alternatives have
R. Gills; P. Lewandowski; B. Ooms; N. Reusen; W. Van Laer; R. Walthery
Partnering and the WCI blast furnace reline
In 1993, WCI Steel entered into a partnership agreement to perform a blast furnace reline. The reline included a complete rebrick from the tuyere breast to the furnace top including the tapholes. Also included was the replacement of the Paul Wurth top equipment from the receiving hoppers through the gearbox and distribution chute, a skip incline replacement, and installation of tilting runners and a casthouse roof. The bustle pipe and hot blast main were repaired. One stove was also replaced. The reline was accomplished in 36 days, wind to wind, which allowed for 29 days of construction inside the blast furnace proper.
Musolf, D.W. [WCI Steel, Inc., Warren, OH (United States)
Possibilities for intensifying blast-furnace smelting
An article published earlier by I. E. Sperkach and I. F. Kurunov [Metallurg, No. 2 (2005)] presented additional information\\u000a in support of the author�s proposal that blast-furnace smelting practice be changed over to the use of 600 kPa top-gas pressure\\u000a and a high-parameter combination blast (oxygen content up to 42%, natural-gas consumption up to 250 m3\\/ton pig). A blast-furnace complex
G. Yu. Kryachko
Dry media blasting with wheat starch
The brand name TECHNOSTRIP covers several types of installations and facilities. These were developed mainly to meet the requirements of customers in the aeronautic field. The range of products includes: complete self-supporting and semi-automated system for aircraft stripping; large-size blasting booth for semi-automatic stripping; manual blasting booth; and sealed and portable manual stripping head. Wheat starch media was developed for particle blasting stripping and is used in TECHNOSTRIP. This paper reviews its origins and use as well as use of automated facilities, reliability, effects on materials, effects on environment, and utilization examples.
Abrasion Testing of Critical Components of Hydrokinetic Devices
The objective of the Abrasion Testing of Critical Components of Hydrokinetic Devices (Project) was to test critical components of hydrokinetic devices in waters with high levels of suspended sediment � information that is widely applicable to the hydrokinetic industry. Tidal and river sites in Alaska typically have high suspended sediment concentrations. High suspended sediment also occurs in major rivers and estuaries throughout the world and throughout high latitude locations where glacial inputs introduce silt into water bodies. In assessing the vulnerability of technology components to sediment induced abrasion, one of the greatest concerns is the impact that the sediment may have on device components such as bearings and seals, failures of which could lead to both efficiency loss and catastrophic system failures.
Worthington, Monty [ORPC Alaska] [ORPC Alaska; Ali, Muhammad [Ohio University] [Ohio University; Ravens, Tom [University of Alaska Anchorage] [University of Alaska Anchorage
Wheel Abrasion Experiment Metals Selection for Mars Pathfinder Mission
A series of metals was examined for suitability for the Wheel Abrasion Experiment, one of ten microrover experiments of the Mars Pathfinder Mission. The seven candidate metals were: Ag, Al, Au, Cu, Ni, Pt, and W. Thin films of candidate metals from 0.1 to 1.0 micrometer thick were deposited on black anodized aluminum coupons by e-beam and resistive evaporation and chemical vapor deposition. Optical, corrosion, abrasion, and adhesion criteria were used to select Al, Ni, and Pt. A description is given of the deposition and testing of thin films, followed by a presentation of experimental data and a brief discussion of follow-on testing and flight qualification.
Hepp, Aloysius F.; Fatemi, Navid S.; Wilt, David M.; Ferguson, Dale C.; Hoffman, Richard; Hill, Maria M.; Kaloyeros, Alain E.
Microstructure and abrasive wear in silicon nitride ceramics
It is well known that abrasive wear resistance is not strictly a materials property, but also depends upon the specific conditions of the wear environment. Nonetheless, characteristics of the ceramic microstructure do influence its hardness and fracture toughness and must, therefore, play an active role in determining howa ceramic will respond to the specific stress states imposed upon it by the wear environment. In this study, the ways in which composition and microstructure influence the abrasive wear behavior of six commercially-produced silicon nitride based ceramics are examined. Results indicate that microstructural parameters, such as matrix grain size and orientation, porosity, and grain boundary microstructure, and thermal expansion mismatch stresses created as the result of second phase formation, influence the wear rate through their effect on wear sheet formation and subsurface fracture. It is also noted that the potential impact of these variables on the wear rate may not be reflected in conventional fracture toughness measurements.
Dogan, Cynthia P.; Hawk, Jeffrey A.
Abrasive wear properties of Cr-Cr3Si composites
A series of composites based on the Cr?Cr3Si system, and containing between 50 and 100%Cr3Si, were fabricated by hot pressing. These composites have high stiffness, good thermal conductivity, excellent chemical resistance, and high temperature creep and oxidation resistance, making them potential candidates for hard-facing applications and cutting tools in harsh environments. In this study, the Cr?Cr3Si composites were abrasion tested at ambient temperatures in order to evaluate their wear properties. Single scratch tests were performed to give insight into material removal mechanisms. Although like most metal silicides, these materials behave in a brittle manner, the results of this study indicate that the addition of a ductile second phase (Cr) can enhance both their fracture toughness and abrasive wear resistance. The addition of 10% of the rare earth oxide Er2O3 improves the density of the composite, but has no apparent influence on the wear resistance.
Newkirk, J.W. (University of Missouri-Rolla); Hawk, Jeffrey A.
Post-Cu CMP cleaning for colloidal silica abrasive removal
In this study, an efficient approach for the removal of colloidal silica abrasives from the polished copper surface was proposed and demonstrated. This post-chemical mechanical polishing (CMP) cleaning process combines a buffing process with dilute HNO3\\/benzotriazole (BTA) aqueous solution for copper surface passivation and a polyvinyl alcohol (PVA) brush scrubbing process with wetting surfactants, Triton X-100, for colloidal silica removal.
Po-Lin Chen; Jyh-Herng Chen; Ming-Shih Tsai; Bau-Tong Dai; Ching-Fa Yeh
Wear behavior of materials in magnetically assisted abrasive flow machining
The finish machining of precision components constitutes one of the most challenging and expensive stages in a manufacturing process. Abrasive flow machining (AFM) is a non-traditional machining technique, which is capable of providing excellent surface finish on difficult-to-approach regions on a wide range of components. Not much research work has hitherto been reported regarding process behavior and performance improvement of
Sehijpal Singh; H. S Shan; P Kumar
Abrasive wear properties of Cr�Cr 3Si composites
A series of composites based on the Cr�Cr3Si system, and containing between 50 and 100%Cr3Si, were fabricated by hot pressing. These composites have high stiffness, good thermal conductivity, excellent chemical resistance, and high temperature creep and oxidation resistance, making them potential candidates for hard-facing applications and cutting tools in harsh environments. In this study, the Cr�Cr3Si composites were abrasion tested
J. W. Newkirk; Jeffrey A. Hawk
Two-body abrasive wear of electroless nickel composite coatings
The two-body abrasive wear of electroless nickel (EN), EN-silicon carbide, and EN-alumina composite coatings have been investigated using a scratch test with a diamond indenter. The coatings were heat treated at temperatures of 100�500� C. The hardness of the coatings increased with heat treatment temperature from 500 HV100 for the as-deposited condition to 1008 HV100 when fully hardened. Scratch testing
C. Subramanian; E. Pallotta
Abrasion of eroded root dentine brushed with different toothpastes
This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6�3�2�mm) were ground flat and polished. In an area of 4�3�mm on the dentine surface, specimens were submitted to five erosive\\/abrasive events, each one composed by:
M�rcio de Menezes; Cecilia Pedroso Turssi; Anderson Takeo Hara; Danielle Cristine Furtado Messias; M�nica Campos Serra
Dental restorations are commonly prepared from machinable glass-ceramics using modern dental CAD\\/CAM systems. Unfortunately, little is understood about the influence of machining parameters on material removal rates and any damage which could be introduced into the restoration during the abrasive machining processes employed with these systems. These effects are investigated for three experimental machinable glass-ceramics with varying microstructure and one
X. Dong; L. Yin; S. Jahanmir; L. K. Ives; E. D. Rekow
Visualization of the abrasive-waterjet cutting process
Cutting with abrasive waterjets was visualized in three types of materials: Lexan, Lucite and glass. Movie cameras were used\\u000a at speeds of 64 and 1000 frames\\/s to record sequences of the jet penetration in these materials. It was found that the cutting\\u000a process consists of two basic modes of erosion. The first, known as the cutting-wear mode, occurs at relatively
Mohamed Hashish
Occlusive Dressings and the Healing of Standardized Abrasions
Context: Acute skin trauma during sport participation, resulting in partial-thickness abrasions, is common. The limited investigations focusing on the acute wound environment and dressing techniques and the subsequent lack of evidence-based standards complicate clinical wound care decisions. Objective: To examine the effects of occlusive dressings on healing of standardized, partial-thickness abrasions. Design: Controlled, counterbalanced, repeated-measures design. Setting: University laboratory. Patients or Other Participants: Sixteen healthy women (n ?=? 10) and men (n ?=? 6). Intervention(s): Four standardized, partial-thickness abrasions were inflicted. Film, hydrogel, and hydrocolloid occlusive dressings and no dressing (control) were applied. Participants returned on postwound days 1, 3, 5, 7, 10, and 14 for digital imaging. Wound healing time was measured by change in wound contraction (cm2) and change in wound color (chromatic red) and luminance in red, green, and blue color values. Main Outcome Measure(s): Wound contraction, color (chromatic red), and luminance. Results: A day-by-dressing interaction was found for wound contraction, color, and luminance. Post hoc testing indicated that the film and hydrocolloid dressings produced greater wound contraction than the hydrogel and no dressing on days 7 and 10. Film, hydrogel, and hydrocolloid dressings also resulted in greater wound contraction than the control on day 14. Hydrocolloid dressings produced smaller measures of color and greater measures of luminance than no dressing on day 7. Film, hydrogel, and hydrocolloid dressings also resulted in smaller measures of color and greater measures of luminance compared with no dressing on days 10 and 14. Conclusions: When compared with the control (no dressing), the film, hydrogel, and hydrocolloid occlusive dressings were associated with a faster healing rate of partial-thickness abrasions across time measured by wound contraction, color, and luminance. Overall, these data indicate that occlusive dressings were more effective in healing than no dressing was.
Beam, Joel W
Removal of enamel caries with an air abrasion powder.
This study compared the efficiency of air abrasion on enamel caries with selective enamel powder (SEP) or with alumina powder and a negative and positive control group. Ninety-three extracted molars with non-cavitated incipient enamel lesions were selected. After embedding the roots in resin, each lesion was sectioned perpendicular to the surface and photographed. Each lesion was classified microscopically as having or not having dentin involvement. The lesions were distributed into four groups with an equal number of enamel caries with or without dentin involvement. Each group was treated differently: Group 1 had SEP abrasion, Group 2 had alumina abrasion, Group 3 had sodium bicarbonate abrasion (negative control) and Group 4 had bur treatment (positive control). The surface was rephotographed after treatment. Superimposition of the photographs identified areas of "correct-excavation," "under-excavation" and "over-excavation." There were no statistical differences between lesions treated with or without dentin involvement for Groups 2 through 4. However, in the SEP group, all measured areas were significantly influenced by dentin involvement. In pairwise comparisons, no statistical differences were found between the alumina and bur groups. The SEP group, however, showed statistically significant differences for each area compared to the alumina group in enamel caries without dentin involvement. SEP performed as well as alumina and bur in lesions with dentin involvement. SEP is different in its ablative properties toward caries with dentin involvement or no dentin involvement. In terms of dental treatment, SEP seems to have a diagnostic potential for enamel lesions before operative intervention in patients with high caries risk. PMID:20945745
Neuhaus, Klaus W; Ciucchi, Philip; Donnet, Marcel; Lussi, Adrian
Developing a Process Model for Abrasive Flow Machining
\\u000a Abrasive flow machining (AFM) is a unique machining method used to achieve high surface quality on inner, difficult-to-access\\u000a contours and on outside edges. Using AFM, it is possible to deburr complex shaped intersecting holes and to realize pre-defined\\u000a edge rounding on any brittle or hard material. Moreover it is easy to integrate into an automated manufacturing environment.\\u000a Reproducibility of results
E. Uhlmann; V. Mihotovic; H. Szulczynski; M. Kretzschmar
Dressing methods for grinding wheels made of superhard abrasive materials
As a result of the increase in the use of difficult-to-machine materials more and more machining tasks are falling within the sphere of grinding. Since the requirements that must be met by the working accuracy under conditions of high productivity of the working cycle are becoming ever more stringent, high-capacity grinding tools are essential. The development of new, superhard abrasives
G. Spur
On the abrasive wear behaviour of mineral filled polypropylene
The effects of mineral fillers on the wear resistance of polypropylene (PP) have been investigated. A general purpose homopolymer grade was used as the matrix. The mineral fillers investigated were talc, CaCO3, BaSO4 and fly ash, representing a range of morphology, size and hardness. The wear behaviour was assessed by pin-on-paper abrasion tests. The wear surfaces were examined using scanning
B. M. Sole; A. Ball
Application of magnetic abrasive polishing to composite materials
Magnetic abrasive polishing (MAP) is an advanced machining process that can produce smoother surfaces in many material types.\\u000a The present study conducted an experimental assessment of MAP for a newly developed, non-ferrous and aluminum-based composite\\u000a material. A permanent magnet was installed under the workpiece to enhance its magnetic flux density, which had proved insufficient\\u000a for effective MAP. The success of
Tae-Wan Kim; Dae-Min Kang; Jae-Seob Kwak
The change in retentive force of magnetic attachment by abrasion
Magnets are frequently applied to removable dentures as retentive attachments. A magnet-retained removable overdenture might\\u000a be slightly shifted from side to side by eccentric movement in the mouth, and the surface of magnetic attachment may be worn\\u000a as a result. However, the relationship between the retentive force of magnetic attachment and its surface abrasion has not\\u000a been reported. The purpose
Yuanjin Huang; Yasuyuki Tawada; Yoshiaki Hata; Fumihiko Watanabe
An unusually extensive and well preserved marine abrasion platform of Late Pliocene age is present 84 m above sea leve1 north of El Rosario, in Baja California. The surface extends for 6 km along the coast and is up to 3 km wide. The abrasion platform is a major disconformity that separates siltstones of the Upper Cretaceous Rosario Formation from
Jorge Ledesma-V�zquez; Markes E. Johnson; Facultad de Ciencias Marinas
Verification of abrasion measurement of juncture implants using Fourier profilometry
Three dimensional measurements have great use today and it is quite large and important part of the experimental physics. These methods are also used in biomedicine for measuring the abrasion of juncture implants, coxal cotyles and knees. These implants are under stress in the patient's body and therefore they change their shape and waste some material. This waste is a key parameter for examination of quality of the given type of implant. The surface of the used implant is measured and compared with unused one. This comparison gives possibility to enumerate the waste of material of implant. One of the three dimensional optic measurement methods is Fourier profilometry, based on the analysis of harmonic structure projected on the surface of the measured object. It is profilometric method; it means that the surface of measured object is specified in every point of result. Fundamentals of Fourier profilometry, its features and used experimental setup are described in the beginning of the paper. The results of such measurement lead to enumerate the waste of material of implant. The purpose of this contribution is the verification of used method to measure the waste of material of implant. Its principle lies in artificial abrasion made by cutting tool, so the abrasion is defined and known. The surface of the implant is measured before and after this machining and the waste of material of implant is enumerated. This value is compared with an actual waste of material.
Pochmon, Michal; R�ssler, Tom�; Mand�t, Du�an; Gallo, Ji?�; Hrabovsk�, Miroslav
Toothbrush abrasions and noncarious cervical lesions: evolving concepts.
Toothbrush abrasion at the cervical areas of teeth is generally thought to be a result of frequent or forceful toothbrushing, faulty or vigorous technique, filament stiffness or design, dominant hand dexterity, or abrasive dentifrices. However, a review of the evidence-based literature cannot conclusively establish any one factor as the primary etiology of cervical abrasions because of inherent methodological limitations and conflicting results. Rather, a variety of factors related to toothbrushing may act in concert with dental erosion and, possibly, occlusal loading in the creation of noncarious cervical lesions. Individual variation also may make some individuals more susceptible to development and may modify the progression of those lesions. Individual variations may involve oral and dental anatomy, periodontal status or phenotype, and periodontal disease history and treatment. Further research is needed to clearly assess the interaction of all those factors in the development of cervical lesions. Therefore, awareness of a multifactorial etiology in noncarious cervical lesions may help the clinician to formulate an appropriate treatment plan for the patient. PMID:16300231
Litonjua, Luis A; Andreana, Sebastiano; Cohen, Robert E
Characterization of the resistance of pyrolytic carbon to abrasive wear.
Si-alloyed pyrolitic carbon (PyC) is currently employed in many biomedical devices, due to its fairly good biological compatibility and non biodegradeability. For prosthetic heart valve applications, required to operate safely for many years, the resistance to abrasive wear is one of the limiting factors which must be accurately evaluated. The present study reports on abrasive wear testing of Ti/PyC and PyC/PyC sliding couples. For both couples it was found that the wear behaviour can be shifted from a low wear regime, characterised by very small wear rates and reduced scatter, to a high wear regime, characterised by high wear rates and high scatter, due to the presence of particle contamination coming from the environment and/or from the specimen polishing process. Actual biomedical devices, particularly heart valves, should not experience the high wear regime, due to the absence of any hard particle contamination source. The wear observed in these items is in fact minimal and may depend on mechanisms other than abrasive wear. In these conditions the experimental evaluation of the wear behaviour should definetely be performed by tests on actual devices. PMID:8964645
Vitale, E; Giusti, P
Abrasion of abutment screw coated with TiN
STATEMENT OF PROBLEM Screw loosening has been a common complication and still reported frequently. PURPOSE The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and weight loss were measured. Mann-Whitney test with SPSS statistical software for Window was applied to analyze the measurement of weight loss. RESULTS TiN-coated abutment screws of Osstem and 3i showed lesser loss of weight than non-coated those of Osstem and 3i (P < .05, Mann-Whitney test). CONCLUSION Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability.
Jung, Seok-Won; Son, Mee-Kyoung; Chung, Chae-Heon
Confined volume blasting experiments: Description and analysis
A series of bench-scale blasting experiments was conducted to produce rubble beds for use in retorting experiments. The experiments consisted of blasting oil shale with explosives within a confined volume containing 25% void. A variety of blasting geometries was used to control the fragment size distribution and void distribution in the rubble. The series of well controlled tests provided excellent data for use in validating rock fragmentation models. Analyses of the experiments with PRONTO, a dynamic finite element computer code, and a newly developed fracturing model provided good agreement between code predictions and experimental measurements of fracture extent and fragment size. CAROM, a dynamic distinct element code developed to model rock motion during blasting, was used to model the fully fragmented tests. Calculations of the void distribution agreed well with experimentally measured values. 9 refs., 11 figs., 1 tab.
Gorham-Bergeron, E.; Kuszmaul, J.S.; Bickel, T.C.; Shirey, D.L.
Perfluorocarbon vapor tagging of blasting cap detonators
A plug for a blasting cap is made of an elastomer in which is dissolved a perfluorocarbon. The perfluorocarbon is released as a vapor into the ambient over a long period of time to serve as a detectable taggant.
Dietz, Russell N. (Shoreham, NY); Senum, Gunnar I. (Patchogue, NY)
Blast Vibration: Threshold Values and Vibration Control.
A proposal for Finnish blast vibration standards and a calculation model for the extent of the zones for building inspection, risk analysis, and vibration measurements are given. The international conclusion is that particle velocity is the best descripti...
R. Vuolio
Improvement of Blasting Techniques in Opencast Mines.
Experience to date indicates that the most important factors affecting the degree of blasting required are the homogeneity of the hard rocks and their overall thickness, taken together with the amount of regional jointing, stratification fractures and ind...
Creating successful blast furnace refractory systems
Successful lifetimes of the refractories utilized in the blast furnace are dependent on a variety of external factors such as operation, geometry, cooling capability, configuration and arrangement, as well as refractory properties. These external factors, as well as the properties required to withstand the main mechanisms of wear, combine to create the successful refractory system. These significant factors and properties are reviewed with the intention of providing guidelines required for successful refractory performance in the blast furnace.
Dzermejko, A.J. [UCAR Carbon Co., Inc., Columbia, TN (United States)
Blast overpressures from medium scale BLEVE tests
The measured blast overpressures from recent tests involving boiling liquid expanding vapour explosions (BLEVE) has been studied. The blast data came from tests where 0.4 and 2m3 ASME code propane tanks were exposed to torch and pool fires. In total almost 60 tanks were tested, and of these nearly 20 resulted in catastrophic failures and BLEVEs. Both single and two-step
A. M. Birk; C. Davison; M. Cunningham
Lightweight Energy Absorbers for Blast Containers
Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.
Balles, Donald L.; Ingram, Thomas M.; Novak, Howard L.; Schricker, Albert F.
Effects of mine blasting on residential structures
Blasting is common in the coal industry to remove rock overburden so that the exposed coal can be mechanically excavated. The ground vibrations and air blast produced by blasting are often felt by residents surrounding the mines. There has been a trend for regulatory authorities, especially those concerned with the environment, to impose low limits on blast vibration levels in response to community pressure, based on human perception and response to vibration. This paper reports the findings of an extensive study on a house which was located adjacent to a coal mine. The house was monitored for over 1 year and was subjected to ground peak particle velocity (PPV) ranging from 1.5 to 222 mm/s. The house was instrumented with accelerometers to measure its dynamic response due to blasting and it was also monitored for cracks before and after each blast. Based on this study, ground motion amplifications along the height of the structure have been established. A simplified methodology presented in this paper has been used to estimate the ground PPV at which cracking is likely.
Gad, E.F.; Wilson, J.L.; Moore, A.J.; Richards, A.B. [Swinburne University of Technology, Hawthorn, Vic. (Australia). Faculty of Engineering & Industrial Science
Methods for predicting rubble motion during blasting
Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. Many in situ extraction techniques require rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. Two analytical methods are presented which describe the large rubble motion during blasting. These methods are intended to provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences. In both these methods, the rock medium is represented by a series of discrete, discontinuous regions (bodies, masses). The use of discontinuous techniques rather than the classical continuum methods, results in better approximations to the rubble motion. These regions are set in motion by pressure loads from the explosive. The motion of these regions is then calculated numerically using interaction laws between regions in contact. The basis for these models or methods is presented along with the background for selecting explosive pressure loads and rock mass material behavior. Typical examples, including both cratering and bench blasting geometries, are discussed which illustrate the use of these models to predict rubble motion. Such engineering representations appear to provide a practical method for use in predicting rubble motion and a tool for design evaluation of blasting in confined geometries.
Schamaun, J.T.
Ultra Safe And Secure Blasting System
The Ultra is a blasting system that is designed for special applications where the risk and consequences of unauthorized demolition or blasting are so great that the use of an extraordinarily safe and secure blasting system is justified. Such a blasting system would be connected and logically welded together through digital code-linking as part of the blasting system set-up and initialization process. The Ultra's security is so robust that it will defeat the people who designed and built the components in any attempt at unauthorized detonation. Anyone attempting to gain unauthorized control of the system by substituting components or tapping into communications lines will be thwarted in their inability to provide encrypted authentication. Authentication occurs through the use of codes that are generated by the system during initialization code-linking and the codes remain unknown to anyone, including the authorized operator. Once code-linked, a closed system has been created. The system requires all components connected as they were during initialization as well as a unique code entered by the operator for function and blasting.
Hart, M M
Pipeline response to blasting in rock
Twenty-one highway construction blasts were used to record pipeline data from production shots that consisted of small explosive arrays with delays among the explosive holes. A 30-in pipe section and a 12-in. pipeline in the vicinity of the highway construction work were instrumented with strain gages. The data provided an opportunity to determine if the estimating equations and techniques developed with soil data could be modified and applied to real world blasting situations in rock. The construction shots were fired in a solid rock area through which trenches for the pipes had been cut, and the pipes installed with a soil and fragmented rock backfill. Maxi pipe stresses induced by the blasts were computed from strains in circumferential and longitudinal directions. Analysis of these stresses and comparisons with soil blasting equations revealed that the single-point source equation provided a realistic upper-bound estimate of max stress to be expected in bench type construction blasting. However, additional work is required in model scale and actual scale experiments. Delays are also discussed. Analysis of ground vibration data was also performed. Several particle velocity prediction equations are reviewed, as well as problems in relating peak particle velocity data to pipe stress data. Use of pipe stress data to develop safe blasting criteria for buried pipelines is advocated instead of traditional peak particle velocity.
Esparza, E.D. (Southwest Research Inst., San Antonio, TX (United States))
Evaluation of Gritting Strategies for High Angle of Attack Using Wind Tunnel and Flight Test Data for the F/A-18
A subsonic study of high-angle-of-attack gritting strategies was undertaken with a 0.06-scale model of the F/A-18, which was assumed to be typical of airplanes with smooth-sided forebodies. This study was conducted in the Langley 7- by 10-Foot High-Speed Tunnel and was intended to more accurately simulate flight boundary layer characteristics on the model in the wind tunnel than would be possible by using classical, low-angle-of-attack gritting on the fuselage. Six-component force and moment data were taken with an internally mounted strain-gauge balance, while pressure data were acquired by using electronically scanned pressure transducers. Data were taken at zero sideslip over an angle-of-attack range from 0 deg to 40 deg and, at selected angles of attack, over sideslip angles from -10 deg to 10 deg. Free-stream Mach number was fixed at 0.30, which resulted in a Reynolds number, based on mean aerodynamic chord, of 1.4 x 10(exp 6). Pressure data measured over the forebody and leading-edge extensions are compared to similar pressure data taken by a related NASA flight research program by using a specially instrumented F/A-18, the High-Alpha Research Vehicle (HARV). Preliminary guidelines for high-angle-of-attack gritting strategies are given.
Hall, Robert M.; Erickson, Gary E.; Fox, Charles H., Jr.; Banks, Daniel W.; Fisher, David F.
Thickness of softened human enamel removed by toothbrush abrasion: an in vitro study.
The aim of the study was to assess the thickness of softened enamel removed by toothbrushing. Human enamel specimens were indented with a Knoop diamond. Softening was performed with citric acid or orange juice. The specimens were brushed in a brushing machine with a manual soft toothbrush in toothpaste slurry or in artificial saliva. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% confidence interval) were recorded in treatment groups (in nanometers): (1) citric acid, abrasion with slurry = 339 (280-398); (2) citric acid, abrasion with artificial saliva = 16 (5-27); (3) orange juice, abrasion with slurry = 268 (233-303); (4) orange juice, abrasion with artificial saliva = 14 (5-23); (5) no softening, abrasion with slurry = 28 (10-46). The calculated thickness of the softened enamel varied between 254 and 323 nm, depending on the acid used. PMID:19499254
Voronets, J; Lussi, A
Blasting injuries in surface mining with emphasis on flyrock and blast area security
Problem: Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgment or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preventive measures. Method: This study examines publications by MSHA, USGS, and other authors. The primary source of information was MSHA's injury-related publications. Results: During the
T. S. Bajpayee; T. R. Rehak; G. L. Mowrey; D. K. Ingram
Friction coefficient and abrasive wear modes in ball-cratering tests conducted at constant normal force and constant pressure�Preliminary results
The micro-scale abrasive wear test by rotative ball has gained large acceptance in universities and research centers, being widely used in studies on the abrasive wear of materials. Two wear modes are usually observed in this type of test: �rolling abrasion� results when the abrasive particles roll on the surface of the tested specimen, while �grooving abrasion� is observed when
R. C. Cozza; D. K. Tanaka; R. M. Souza
Minimization of carryover for high-throughput liquid chromatography with tandem mass spectrometry analysis of 14 mycotoxins in corn grits.
A method for the simultaneous analysis of 14 mycotoxins with the minimization of carryover was developed. Our verification experiments suggested that the carryover occurred due to the chelation of fumonisins with the metal. To wash the fumonisins from the metal, the inner surface of the injection needle was rinsed with 10�mM trisodium citrate and 1% formic acid in water/methanol/acetonitrile/isopropanol after each injection, and the analysis was performed on a metal-free Mastro C18 column. This approach remarkably minimized the carryover of fumonisins. Fourteen mycotoxins in samples were extracted with 2% acetic acid in water/acetonitrile and a quick, easy, cheap, effective, rugged, and safe extraction kit, purified on a MultiSep 229 Ochra, and then quantified by liquid chromatography with tandem mass spectrometry. Determinations performed using this method produced a linearity greater than 0.99 and recoveries ranging from 72.6 to 117.4%, with good intraday precision from 4.0 to 12.4%, and interday precision from 6.5 to 17.0%. The limits of detection ranged from 0.01 to 0.71�?g/kg, demonstrating that a highly sensitive method for the simultaneous analysis of mycotoxins over a wide range of concentrations was achieved with minimal carryover. When 12 samples of commercially available corn grits were analyzed with this method, deoxynivalenol, fumonisin B1, fumonisin B2, fumonisin B3, and zearalenone were present most frequently. PMID:24723378
Tamura, Masayoshi; Matsumoto, Keiko; Watanabe, Jun; Iida, Junko; Nagatomi, Yasushi; Mochizuki, Naoki
Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD
This paper presents the study of fluid flow and heat transfer in a solar air heater by using Computational Fluid Dynamics (CFD) which reduces time and cost. Lower side of collector plate is made rough with metal ribs of circular, square and triangular cross-section, having 60 inclinations to the air flow. The grit rib elements are fixed on the surface in staggered manner to form defined grid. The system and operating parameters studied are: e/D{sub h} = 0.044, p/e = 17.5 and l/s = 1.72, for the Reynolds number range 3600-17,000. To validate CFD results, experimental investigations were carried out in the laboratory. It is found that experimental and CFD analysis results give the good agreement. The optimization of rib geometry and its angle of attack is also done. The square cross-section ribs with 58 angle of attack give maximum heat transfer. The percentage enhancement in the heat transfer for square plate over smooth surface is 30%. (author)
Karmare, S.V. [Department of Mechanical Engineering, Government College Engineering, Karad 415 124, Maharashtra (India); Shivaji University, Kolhapur, Maharashtra (India); Tikekar, A.N. [Department of Mechanical Engineering, Walchand College of Engineering, Sangli (India); Shivaji University, Kolhapur, Maharashtra (India)
Blast waves from cylindrical charges
Comparisons of explosives are often carried out using TNT equivalency which is based on data for spherical charges, despite the fact that many explosive charges are not spherical in shape, but cylindrical. Previous work has shown that it is possible to predict the over pressure and impulse from the curved surface of cylindrical charges using simple empirical formulae for the case when the length-to-diameter ( L/ D) ratio is greater or equal to 2/1. In this paper, by examining data for all length-to-diameter ratios, it is shown that it is possible to predict the peak over pressure, P, for any length-to-diameter ratio from the curved side of a bare cylindrical charge of explosive using the equation P=K_PM(L/D)^{1/3}/R^3, where M is the mass of explosive, R the distance from the charge and K_P is an explosive-dependent constant. Further out where the cylindrical blast wave `heals' into a spherical one, the more complex equation P=C_1(Z^' ' })^{-3}+C_2(Z^' ' })^{-2}+C_3(Z^' ' })^{-1} gives a better fit to experimental data, where Z^' ' } = M^{1/3}(L/D)^{1/9}/D and C_1, C_2 and C_3 are explosive-dependent constants. The impulse is found to be independent of the L/ D ratio.
Knock, C.; Davies, N.
Blast noise impacts on sleep
Firing large guns during the hours of darkness is essential to combat readiness for the military. At the same time most people are particularly sensitive to noise when sleeping or trying to fall asleep. Laboratory studies done by Griefahn [J. Sound and Vib. 128, 109-119 (1989)] and Luz [see Luz et al., ERDC/CERL, TR-04-26 (2004)] suggest that a time period at night may exist where people are more tolerant to large weapon impulse noise (blast noise) and therefore, are less likely to be awakened from noise events. In the fall of 2004, a field study was conducted around a military installation to determine if such a time period(s) exists. Noise monitors were set up inside and outside of residents homes to record noise levels from live military training activities and actimeters were worn by participants sleeping their natural environment to measure sleep disturbance and awakening. The method and results of this study will be presented. [Work supported by US Army Engineer Research and Development Center CERL.
Nykaza, Edward T.; Pater, Larry L.
Study of magnetic abrasive finishing in free-form surface operations using the Taguchi method
This study employed magnetic abrasive finishing (MAF) to conduct free-form surface abrasion of stainless SUS304 material operations.\\u000a The operations were demonstrated using a permanent magnetic finishing mechanism installed at the CNC machining center. The\\u000a operations were performed using the Taguchi experimental design, considering the effects of magnetic field, spindle revolution,\\u000a feed rate, working gap, abrasive, and lubricant. Furthermore, the experimental
Ching-Tien Lin; Lieh-Dai Yang; Han-Ming Chow
Micro machining of an STS 304 bar by magnetic abrasive finishing
A magnetic abrasive finishing process is a method of non-traditional precision machining in which the finishing process is\\u000a completed using magnetic force and magnetic abrasives. In this research, a STS 304 cylindrical workpiece was finished using\\u000a a magnetic abrasive finishing process at 30,000 rpm, and the roughness, roundness, and changes in the micro-diameter were\\u000a investigated. The study showed that it
Ik-Tae Im; Sang Don Mun; Seong Mo Oh
An investigation into superficial embedment in mirror-like machining using abrasive jet polishing
This study performs experimental investigation into the application of abrasive jet polishing (AJP) to the surface finishing\\u000a of electrical-discharge-machined SKD61 mold steel workpieces. The results indicate that the AJP processing conditions which\\u000a optimize the surface quality of the SKD61 workpiece when polishing using #2000SiC abrasives are as follows: an abrasive material\\u000a to additive ratio of 1:2, an impact angle of
Feng-Che Tsai; Biing-Hwa Yan; Chun-Yu Kuan; Rong-Tzong Hsu; Jung-Chou Hung
Abrasive wear characteristics of plasma sprayed nanostructured alumina\\/titania coatings
In this paper, the plasma spray technique was used to deposit coatings with reconstituted nanostructured Al2O3\\/TiO2 powders. The abrasive wear resistance of the ceramic coatings was evaluated using diamond abrasives. The result showed that the abrasive wear resistance of the coatings produced using the nanostructured Al2O3\\/TiO2 powders is greatly improved compared with the coating produced using the conventional Al2O3\\/TiO2 powder
You Wang; Stephen Jiang; Meidong Wang; Shihe Wang; T. Danny Xiao; Peter R Strutt
The effects of particle characteristics on three-body abrasive wear
The effects of abrasive particle characteristics, especially shape and hardness, on three-body abrasive wear of metallic samples have been investigated. The experimental tests were carried out on a modified pin-on-disc tribometer using dry abrasive particles and on a ball-on-plate tribometer using slurry. Spike parameter quadratic fit (SPQ) was used in the characterization of particles angularity. Better correlation between wear rates
G. B Stachowiak; G. W Stachowiak
Mapping the micro-abrasion resistance of WC\\/Co based coatings in aqueous conditions
Significant progress has been made in recent years on the study of micro-abrasion mechanisms of materials. Regimes of micro-abrasion have been proposed which identify whether the wear occurs either by a two-body or a three-body mechanism. Micro-abrasion maps have been constructed showing the variation in wear regime, as a function of applied load and sliding distance. There has, however, been
M. M. Stack; M. T. Mathew
Abrasive wear by TiO 2 particles on hard and on low friction coatings
The ball cratering test was used to study the abrasive wear resistance of a wide variety of coatings against TiO2 particles. The rutile TiO2, used as white pigment, causes mild abrasive wear in mixers, dyes, injection moulds and other components in the paint and plastic processing. The tests yield a clear ranking of the coatings. The abrasive wear due to
K Van Acker; K Vercammen
Analytical method for softness abrasive flow field based on discrete phase model
Aiming at the problem of difficult contact finishing for mini structural surface in course of mould manufacturing, a new no-tool\\u000a precision machining method based on soft abrasive flow machining (SAFM) was proposed. It allocated restrained component near\\u000a surface machined, constituted restrained abrasive flow passage, and made the surface become a segment of passage wall. It\\u000a could control turbulence abrasive flow
ShiMing Ji; FengQing Xiao; DaPeng Tan
Influence of molybdenum, vanadium, and niobium on the abrasion resistance of high-chromium cast iron
1.Alloying additions of 0.17�2.33% Mo in cast irons considerably improves (particularly in contact with quartz sand) their abrasive wear resistance. This is due to the improved resistance of their martensite matrix and carbides to brittle fracture when in contact with abrasive grains.2.Alloying additions of vanadium decrease the abrasive wear resistance of cast irons. This is related to the negative influence
N. Sh. Shadrov; L. G. Korshunov; V. P. Cheremnikh
The abrasive wear behaviour of Al-SiCp composites for automotive parts
The present work reports on the continuous abrasives wear behaviour of Al-SiCp composites with 5 to 30 wt. % of SiC particulates. A pin-on-drum wear-testing machine was designed and fabricated to study the effects of wt. % of SiCp, load, relative velocity and abrasive particle characteristics on abrasive wear behaviour of Al-SiCp composite with 5 to 30 wt. % of
G. Hemath Kumar; B. R. Ramesh Bapu; R. Sagar; H. Mohit
New Experimental Rig to Investigate Abrasive�Corrosive Characteristics of Metals in Aqueous Media
A new tribometer to investigate a conjoint effect of three-body abrasion and corrosion has been developed. In this design,\\u000a a flat wear sample is loaded against a rotating cylindrical disc counterface and the abrasive slurry is delivered to the contact\\u000a interface. Capabilities of the newly developed tribometer have been assessed through conducting abrasion�corrosion tests involving\\u000a simultaneous electrochemical measurements. In this
M. Salasi; G. B. Stachowiak; G. W. Stachowiak
Abrasion of Steel by Ceramic Coatings: Comparison of RF-DLC to Sputtered B4C
The abrasion rates of steel balls sliding against a very smooth diamond-like carbon (DLC) coating and a rough boron carbide (B4C) coating are compared. The initial abrasiveness of the B4C coating is about 2 orders of magnitude greater than that of the DLC coating. Both coatings exhibit a rapid decrease in their abrasiveness with sliding distance, but the details of
Stephen J. Harris; Gordon G. Krauss; Steven J. Simko; Timothy J. Potter; Robert W. Carpick; Bridget Welbesc; Martin Grischked
The prevalence and risk factors associated with forelimb skin abrasions and sole bruising in preweaning piglets
The presence of skin abrasions and sole bruising in 264 preweaning piglets (1�30 days old) from 13 breeding units in south west England was investigated in 1995. The mean prevalence of forelimb skin abrasions among the pigs on the study farms was 36% (range 0�59%) and sole bruising was 50% (range 0�95%). Skin abrasions were located on three aspects on
N. Mouttotou; F. M. Hatchell; L. E. Green
Blast Resistance and Damage Modelling of Fibre Metal Laminates to Blast Loads
A robust and efficient computational model has been developed which is capable of modelling the dynamic non-linear behaviour of GLARE panels subjected to blast loadings. Numerical model validation have been performed considering case studies of GLARE panels subjected to a blast-type pressure pulse for which experimental data on the back-face deflection and post-damage observations were available. Excellent agreement of mid-point deflections and evidence of severe yield line deformation were shown and discussed against the performed blast tests. A further parametric study identified GLARE as a potential blast attenuating structure, exhibiting superior blast potential against monolithic aluminium plates. It was concluded that further work needed to be carried out to take into account the influence of geometry (cylindrical structures), pre-pressurisation effects and boundary conditions
Mohamed, Galal F. A.; Soutis, Costas; Hodzic, Alma
Modelling of blast loading on aboveground structures - II. Internal blast and ground shock
Recent studies of the nature and structural effects of confined explosions, contact blast and explosion-induced ground shock are presented. High explosive blast is distinguished from that due to a gaseous deflagration. The effects of confinement and venting are considered in the evaluation of dynamic loads. Maxima for the initial internal blast pressure can be estimated from the scaled blast data or theoretical analyses of normal blast wave reflection from a rigid wall. Semi-empirical relations and prediction methods for gas pressures for many types of internal explosions including high explosives, gas mixtures and dust suspensions are given on the basis of pseudo-static character. The loading of a contact explosion and the associated effects on a concrete target are determined as functions of charge weight, concrete strength and member thickness. In the final part, the evaluation of both airblast-induced ground shock and directly transmitted motion are included in simple form without considering the soil-structure interaction.
Beshara, F. B. A.
Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that the MAN GHH copper staves do not experience large temperature fluctuations and that the hot face temperatures will be below 250 F. This suggests that the copper staves maintain a more stable accretion layer than the cast iron staves. Contrary to initial expectations, heat flux to the copper staves is 50% lower than that to cast iron staves. The more stable accretion layer acts as an excellent insulator for the stave and greatly reduces the number of times the hot face of the stave is exposed to the blast furnace process and should result in a more stable furnace operation. In the future, it may be unnecessary to use high quality, expensive refractories in front of copper staves because of the highly stable accretion layer that appears to rapidly form due to the lower operating temperature of the staves. There is a balance of application regions for cast iron and copper staves that minimizes the capital cost of a blast furnace reline and provides an integrated cooling system with multiple campaign life potential. Cast iron staves are proven cooling elements that are capable of multiple campaign life in areas of the blast furnace which do not experience extreme heat loads. Copper staves are proving to be an effective and reliable blast furnace cooling element that are subject to virtually no wear and are projected to have a longer campaign service life in the areas of highest thermal load in the blast furnace.
Helenbrook, R.G. [ATSI, Inc., Amherst, NY (United States); Kowalski, W. [Thyssen Stahl AG, Duisburg (Germany); Grosspietsch, K.H. [Preussag Stahl AG, Saltzgitter (Germany); Hille, H. [MAN GHH AG, Oberhausen (Germany)
Blast-wave characteristics near Site 300
The blast-wave overpressures propagating in the atmosphere near the Lawrence Livermore National Laboratory (LLNL) Site 300 have been measured at selected locations to determine whether the Site 300 blast operations will be hindered by the proposed construction of a residential development adjacent to its border.We tested high-explosives (HE) weights ranging from 14 to 545 lb under various weather conditions. Although more tests should be conducted before a definitive statement can be made on the blast propagation near Site 300, we offer the following preliminary interpretation of the results obtained to date. The readings at the closest locations show that the blast-wave overpressures exceed the 126-decibel (dB) level established by LLNL at about 250 lb of HE detonation. The weather conditions do not materially affect the pressure levels at these locations. Insufficient test data exist along the Corral Hollow Road perimeter, making it difficult to reasonably predict HE blast effects along the southern border. Therefore, we recommend that additional measurements be made along this and other boundaries in future tests, to provide more comprehensive data to help determine the blast-wave propagation characteristics in the proposed development areas. Blast-wave focusing may occur in the proposed residential development area under certain weather conditions. We recommend that this possibility should be addressed for its potentially adverse impact on the proposed residential area. Because the testing ground controlled by Physics International, Inc. (PI) is adjacent to Site 300, it is important to be aware of PI`s detonation activities. Peak overpressure measurements near PI`s Corral Hollow Road entrance reveal that PI shots over 25 lb HE have exceeded 126 dB, the limit established by LLNL for safe operations.
Kang, Sang-Wook; Kleiber, J.C. Jr.
High explosive testing of a corrugated metal blast shelter with membrane blast doors
In October 1983 the Defense Nuclear Agency (DNA) sponsored a high-explosive blast test, nicknamed DIRECT COURSE. This event simulated the blast effects from a one-kiloton nuclear detonation and provided an environment for the testing of selected blast and fallout shelters for their structural integrity. Under work for the Federal Emergency Management Agency (FEMA), the Oak Ridge National Laboratory (ORNL) fielded a set of experiments at the DIRECT COURSE event which were directed toward reducing the cost of blast shelter for small groups of people, such as workers in critical industries (keyworkers). Six items were tested: three scale models of a corrugated metal blast shelter and three full-size blast door closures for such a shelter. The three shelters survived blast overpressures up to 2.55 MPa (225 psi), a level which is equivalent to being approximately 800 m (0.5 mile) from a 1 megaton nuclear detonation. Each shelter model was 180 cm (6 ft.) long by 60 cm (2 ft.) in diameter, was buried about 60 cm (2 ft.) below ground level, and represented a 1/4-scale version of a full-size blast shelter which would be capable of supporting 12 to 18 occupants. The three full-size, 90 cm (35 in.) diameter, blast doors for such a shelter also successfully resisted the same range of blast overpressure. Each door weighed less than 45 kg (100 lb) and incorporated a novel, yielding-membrane design. These sheet metal membranes were between 1.3 and 2.0 mm (0.050 and 0.080 in.) thick and were supported by an edge beam (hoop).
Zimmerman, G.P.; Chester, C.V.
30 CFR 817.66 - Use of explosives: Blasting signs, warnings, and access control.
...Blasting signs, warnings, and access control. 817.66 Section 817.66...Blasting signs, warnings, and access control. (a) Blasting signs. Blasting...in § 817.64(a). (c) Access control. Access within the...
30 CFR 57.6404 - Separation of blasting circuits from power source.
...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...
30 CFR 56.6404 - Separation of blasting circuits from power source.
... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...