An automated tube filling machine and process having a plurality of work stations, a rotating disc to deliver the tubes to the work stations and a central processing unit to control implementation of the work stations and rotation of the disc.

It has long been customary to merchandise many products in tubes. Typical products packaged in tubes include toothpaste, lotion, caulking compound, etc.
As a result a significant industry exists in filling tubes. Currently, tube filling is generally performed by automated machinery.
Rotary piston tube filling machines are probably the most common machinery now in use for filling tubes. Typical examples of rotary piston tube filling machines are shown in U.S. Pat. No. 2,958,346 and U.S. Pat. No. 3,825,043, which are incorporated herein by reference thereto. Additionally, such machines are currently manufactured by Norden Packaging Machinery AB, Kalix Inc., Iwk Packaging Machinery, Inc. Pack. Dev. Co. Ltd. and Aktron, Inc.
Typically, rotary tube filling machines are mechanically driven by cams and chains. The tubes travel on conveyors or rotating discs to various work stations required to perform the functions necessary to fill a tube. The various functions include loading the empty tubes on the conveyor or disc in proper orientation, cleaning the interior of the empty tubes, filling the tubes, sealing the filled tubes and discharging the filled tubes from the conveyor or disc. However, with the conventional tube filling machinery, each time a new tube is used or a different fill substance is utilized, the cams and chains must be adjusted to accommodate the varying heights and angles of the tubes, the orientation marks, the time and temperature associated with sealing different tubes and the time needed to fill the tubes. Adjustment of the cams and chains is time consuming and tends to create contamination problems because of the need to oil and grease various components. Thus, after the necessary adjustments are made, time must be spent cleaning the machine to insure that the oil and grease do not come into contact with the tubes or the tubes must be cleaned before the packaging occurs. Another problem with cams is the wear associated with normal use that can cause shifting of the tubes during travel on the conveyor or disc.
Further, current tube filling machinery lacks the capacity to afford determination of adjustment corrections at the individual stations. Typically, the entire machine must be activated to be able to check any single function.

Automatic tube filling device and process


A method of densifying a reaction bonded silicon nitride article is disclosed. In accordance with the broadest principles disclosed, a densification aid is incorporated into a reaction bonded silicon nitride article. The so-made reaction bonded silicon nitride article is enclosed in a chamber which also contains a mixture of silicon nitride powder and powder the same as the densification aid incorporated into the reaction bonded silicon nitride article. The reaction bonded silicon nitride article, and the powder mixture associated therewith, is subjected to a nitrogen gas pressure sufficient to prohibit a significant volatilization of silicon nitride at a sintering temperature. The reaction bonded silicon nitride article, the powder mixture and nitrogen gas associated therewith are heated to a temperature above 1700.degree. C. for a time sufficient to permit sintering of that article whereby the strength of the reaction bonded silicon nitride article is increased. In accordance with preferred teachings, the densification aid can be selected from the group of materials consisting of magnesium oxide, yttrium oxide, cerium oxide and zirconium oxide.

We have been working in the area of manufacturing components for gas turbine engines from silicon nitride. In such applications, it is desired to obtain the maximum strength from the silicon nitride material as that material is subjected to severe operating conditions as a component of the hot gas flow path of such a turbine engine. We have been attempting to manufacture complex shaped, high density reaction bonded silicon nitride articles for use, for example, as the rotor of a gas turbine engine.
The process of this specification is one by which high density silicon nitride articles of complex shape can be made. A complex shaped, reaction bonded silicon nitride article of moderate density can be made by methods already known in the art, such as injection molding and slip casting processes. By the process of our invention, the thus made reaction bonded silicon nitride article of moderate density is sintered so that the strength and density are increased. During the sintering, there is some slight shrinkage of the article, but not such a significant amount of shrinkage as will produce distortion, cracking, or other failures in the article.
By sintering, we mean the following. During a sintering and densification operation, the particles of a powder first form necks between adjacent particles which become the grain boundaries. Between the grain boundaries, a liquid phase may exist. The densification proceeds by a reduction in the number and size of the spaces or pores between the particles as they migrate into these grain boundaries through a transport mechanism which is followed by a partial collapse or moving together of the center points of the grains, thus producing densification.
In the method of this invention, we can tolerate a small degree of shrinkage of the article from its as-formed, low density state to its densified state. By its as-formed state, we mean a reaction bonded silicon nitride article which has been made through a process in which materials such as silicon particles are slip cast to form a particular configuration and thereafter nitrided, or wherein materials such as silicon particles are injection molded with a suitable binder, subjected to a pyrolizing operation, and thereafter nitrided. The article is not a reaction bonded silicon nitride article until after the silicon particles have been nitrided in a nitriding operation. By using either slip cast or injection molding techniques, we can make an article of complex configuration such as a rotor for a gas turbine engine. By knowing that the rate of shrinkage is going to be controlled, we can specifically make the asformed article larger than desired so that when the densification and associated shrinkage takes place, the fully densified article will have the dimensions desired in the final article, or be so close thereto that they may be readily machined to the final desired dimensions.
The prior art search conducted on the subject matter of this invention did not uncover any patents which we felt disclosed or anticipated the method of densification set forth in this specification. However, two patents did appear of interest, namely, U.S. Pat. Nos. 3,992,497 and 4,038,092. These patents will be discussed below.
U.S. Pat. No. 3,992,497 discloses a method for making a silicon nitride article in which a silicon nitride powder, not silicon powder, is mixed with a densification aid and heated rapidly to a sintering/densification temperature in the range of from 1500.degree. C. to 1700.degree. C. and held there for a very short period of time in the range from 5 to 30 minutes. Thereafter, the product is rapidly cooled. The patent did not state the particular atmosphere used during the sintering operation. This disclosed process is different from the one disclosed herein in that the temperatures are significantly lower than those used by us, the time at temperature for the sintering operation is very much less than those required in our process and there is no stated requirement that a nitrogen atmosphere be present, as is required in our process. As an additional matter, when silicon nitride powder, rather than the silicon powder we start with, which is subsequently converted into silicon nitride after being formed into the shape of an article, is mixed with a densification aid and thereafter formed into an article which is subsequently sintered, a great deal of shrinkage takes place in the article, e.g., as much as 20% or more.
U.S. Pat. No. 4,038,092 discloses a process for increasing the strength of a reaction sintered silicon nitride body by impregnating the surface of that body with a finely divided alumina. After such impregnation, the article is fired in a nitrogen atmosphere to a temperature in excess of 1200.degree. C. up to about 1400.degree. C. The patent also states that this reaction is carried out under an appreciable pressure of silicon monoxide so that disassociation of silicon nitride and a loss of silicon from the body is avoided. This patent does not teach a sintering of a body, but rather teaches the formation of a surface layer in which the alumina plays a part. Also, the patent states that the use of a silicon monoxide atmosphere is absolutely essential to the process. The process taught in this patent is different than the one to be disclosed in this specification in that the temperature limits are very low, the requirement of a silicon monoxide atmosphere being present during the action, and the fact that alumina is used only to aid in the formation of a surface layer on the article.

Method of densifying a reaction bonded silicon nitride article


A method of providing a relevant subset of information to a client device is based in part on scanning for Wi-Fi access points within range of the client device, using a Wi-Fi database that covers a large target region to retrieve information about these access points, using this information to estimate the position of the mobile client device, selecting a limited region in the vicinity of the estimated location of the client device, and providing information about Wi-Fi access points within this limited region to the client. For efficient transfer and maintenance of data, the target region may be divided into a hierarchy of fixed geographical tiles.

1. Field of the Invention
The invention generally relates to methods and systems for determining the location of a Wi-Fi-enabled device, and, more specifically, to methods and systems for efficiently managing and distributing Wi-Fi location data to a mobile client device so the client can use such information to estimate its position.
2. Discussion of Related Art
In recent years the number of mobile computing devices has increased dramatically, creating the need for more advanced mobile and wireless services. Mobile email, walkie-talkie services, multi-player gaming and call-following are examples of how new applications are emerging on mobile devices. In addition, users are beginning to demand and seek out applications that not only utilize their current location but also share that location information with others. Parents wish to keep track of their children, supervisors need to track the location of the company's delivery vehicles, and a business traveler looks to find the nearest pharmacy to pick up a prescription. All of these examples require an individual to know his own current location or that of someone else. To date, we all rely on asking for directions, calling people to ask their whereabouts, or having workers check-in from time to time with their position.
Location-based services represent an emerging class of mobile applications that leverage the ability of devices to calculate their current geographic position and report that to a user or to a service. Some examples of these services include local weather, traffic updates, driving directions, child trackers, buddy finders and urban concierge services. These new location sensitive devices rely on a variety of technologies that all use the same general concept: using radio signals coming from known reference points, these devices can mathematically calculate the user's position relative to these reference points. Each of these technologies has strengths and weaknesses according to the specific radio technologies and positioning algorithms it employs.
The Global Positioning System (GPS) operated by the US Government leverages dozens of orbiting satellites as reference points. These satellites broadcast radio signals that are picked up by GPS receivers. The receivers measure the time it took for a received signal to travel to the receiver. After receiving signals from three or more GPS satellites the receiver can triangulate its position on the globe. For the system to work effectively, the radio signals must reach the receiver with little or no interference. Weather, buildings or structures, and foliage can interfere with this process because the receivers require a clear line-of-sight to three or more satellites. Interference can also be caused by a phenomenon known as multi-path. The radio signals from the satellites bounce off physical structures causing multiple signals from the same satellite to reach a receiver at different times. Since the receiver's calculation is based on the time the signal took to reach the receiver, multi-path signals confuse the receiver and cause substantial errors.
Cell tower triangulation is another method used by wireless and cellular carriers to determine a user or device's location. The wireless network and the handheld device communicate with each other to share signal information that the network can use to calculate the location of the device. This approach was originally seen as a superior model to GPS since these signals do not require direct line of site and can penetrate buildings better. Unfortunately these approaches have proven to be suboptimal due to the heterogeneous nature of the cellular tower hardware along with the issues of multi-path signals and the lack of uniformity in the positioning of cellular towers.
Assisted GPS is a newer model that combines both GPS and cellular tower techniques to produce a more accurate and reliable location calculation for mobile users. In this model, the wireless network attempts to help GPS improve its signal reception by transmitting information about the clock offsets of the GPS satellites and the general location of the user based on the location of the connected cell tower. These techniques can help GPS receivers deal with weaker signals that one experiences indoors and helps the receiver obtain a 'fix' on the closest satellites quicker providing a faster "first reading". These systems have been plagued by slow response times and poor accuracy—greater than 100 meters in downtown areas.
There have been some more recent alternative models developed to try and address the known issues with GPS, A-GPS and cell tower positioning. One of them, known as TV-GPS, utilizes signals from television broadcast towers (see, e.g., Muthukrishnan, K. et al., Towards Smart Surroundings Enabling Techniques and Technologies for Localization, from Location-and Context-Awareness, Springer Berlin, Heidelberg, May 2005). The concept relies on the fact that most metropolitan areas have 3 or more TV broadcast towers. A proprietary hardware chip receives TV signals from these various towers and uses the known positions of these towers as reference points. The challenges facing this model are the cost of the new hardware receiver and the limitations of using such a small set of reference points. For example, if a user is outside the perimeter of towers, the system has a difficult time providing reasonable accuracy. The classic example is a user along the shoreline. Since there are no TV towers out in the ocean, there is no way to provide reference symmetry among the reference points resulting in a calculated positioning well inland of the user.
Microsoft Corporation and Intel Corporation (through a research group known as PlaceLab) have deployed a Wi-Fi location system using a database of access point locations acquired from amateur scanners (known as "wardrivers") who submit their Wi-Fi scan data to public community web sites (see, e.g., LaMarca, A. et al., Place Lab: Device Positioning Using Radio Beacons in the Wild, in Proceedings of the Third International Conference on Pervasive Computing, May 2005). Examples include WiGLE, Wi-FiMaps.com, Netstumbler.com and NodeDB. Both Microsoft and Intel have developed their own client software that uses the Wi-Fi information submitted by wardrivers as a reference in estimating the location of a client device.
Because individuals voluntarily supply the data, these systems suffer from a number of performance and reliability problems. First, the data across the databases are not contemporaneous; some of the data are new while other portions are 3-4 years old. The age of Wi-Fi location data is important, since over time access points can be moved or taken offline. Second, the data are acquired using a variety of hardware and software configurations. Every 802.11 radio and antenna has different signal reception characteristics affecting the representation of the strength of the signal. Each scanning software implementation scans for Wi-Fi signals in different ways during different time intervals. As a result, the access point information in the database lacks a common standard of reference. Third, the user-supplied data suffer from arterial bias. Because the data is self-reported by individuals who are not following designed scanning routes, the data tends to aggregate around heavily trafficked areas. Arterial bias causes location estimates to be "pulled" towards main arteries, resulting in substantial accuracy errors. Fourth, these databases include the calculated position of scanned access points rather than the raw scanning data obtained by the 802.11 hardware. Each of these databases calculates the access point location differently and each with a rudimentary weighted average formula. The result is that the location estimates for some access points in the database are highly inaccurate.
There have been a number of commercial offerings of Wi-Fi location systems targeted at indoor positioning (see, e.g., Muthukrishnan, K., et al., Towards Smart Surroundings: Enabling Techniques and Technologies for Localization, Lecture Notes in Computer Science, Vol. 3479, pp. 350-362, January 2005; Hazas, M., et al., Location-Aware Computing Comes of Age, IEEE Computer, Vol. 37(2), pp. 95-97, February 2004, both of which are incorporated by reference herein). These systems are designed to address asset and people tracking within a controlled environment like a corporate campus, a hospital facility or a shipping yard. The classic example is having a system that can monitor the exact location of the crash cart within the hospital so that when there is a cardiac arrest the hospital staff doesn't waste time locating the device. The accuracy requirements for these use cases are very demanding typically calling for 1-3 meter accuracy. These systems use a variety of techniques to fine tune their accuracy including conducting detailed site surveys of every square foot of the campus to measure radio signal propagation. They also require a constant network connection so that the access point and the client radio can exchange synchronization information similar to how A-GPS works. While these systems are becoming more reliable for these indoor use cases, they are ineffective in any wide-area deployment. It is impossible to conduct the kind of detailed site survey required across an entire city and there is no way to rely on a constant communication channel with 802.11 access points across an entire metropolitan area to the extent required by these systems. Most importantly outdoor radio propagation is fundamentally different than indoor radio propagation rendering these indoor positioning algorithms almost useless in a wide-area scenario.
There are numerous 802.11 location scanning clients available that record the presence of 802.11 signals and associate this information with a GPS location reading. These software applications are operated manually and produce a log file of the readings. Examples of such applications are Netstumber, Kismet and Wi-FiFoFum. Some hobbyists use these applications to mark the locations of 802.11 access point signals they detect and share them with each other. The management of this data and the sharing of the information is performed on an ad hoc basis. These applications do not perform any calculation as to the physical location of the access point; they merely record the location from which the access point was detected.
Using data gathered by any of these systems requires access to either the raw data that were gathered or the calculated locations for each of the access points. Devices that require the use of these data must somehow gain access to the data. This access is generally accomplished in one of two ways: (i) by means of a network request-response interaction between the mobile device and a networked server; or (ii) by storing a Wi-Fi access point database on the mobile device itself.
Software that operates on mobile devices is often constrained by the limited physical capabilities of such devices and the cost of mobile resources and services. These constraints include both hardware (memory capacity, power storage and consumption, CPU speed, network capacity and availability) as well as cost constraints for network access and bandwidth consumption. These limitations place a burden on any solution that intends to make use of the available resources, and in particular, create an optimization problem for efficiently managing and distributing Wi-Fi location data.
This optimization problem is compounded by the fact that the Wi-Fi location database itself requires frequent updates. This is a result of the transient nature of Wi-Fi access points, which are often moved or decommissioned. Thus, the database must be updated regularly to ensure that it contains relatively current Wi-Fi location information.

This patent is subject to a terminal disclaimer.

Method and system for selecting and providing a relevant subset of Wi-Fi location information to a mobile client device so the client device may estimate its position with efficient utilization of resources


The present invention provides a method to label phospholipids in vivo based on the metabolic incorporation of an alkynyl- or azido-labeled metabolic precursor into phospholipids. The resulting phospholipids have alkynyl or azido moieties, which, upon reaction with a labeled azide or alkyne, respectively, form labeled compounds that can be visualized using optical or electron microscopy with high sensitivity and spatial resolution in cells or tissue. The present method provides a valuable tool for imaging phospholipid synthesis, turnover and subcellular localization in cultured cells as well as in animals.

Phospholipids are the major lipid components of all cellular membranes. There are two classes of phospholipids: those that have a glycerol backbone and those that contain sphingosine. Both classes are present in the biological membranes. Sphingomyelin is the major sphingosine-containing phospholipid. Its general structure consists of a fatty acid attached to sphingosine by an amide linkage. Phospholipids that contain a glycerol backbone are called phosphoglycerides (or glycerophospholipids); these constitute the most abundant class of phospholipid found in nature. The most abundant types of naturally occurring phosphoglyceride are phosphatidylcholine (lecithin), phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, and cardiolipin (Vance, J. E., and Vance, D. E. (2004) Phospholipid biosynthesis in mammalian cells. Biochem Cell Biol., 82, 113-128) The structural diversity within each type of phosphoglyceride is due to the variability of the chain length and degree of saturation of the fatty acid ester groups.
Choline-containing phospholipids have important structural roles in membranes and also play critical roles in cell signaling, either as signaling molecules in their own right or as precursors, through enzymatic hydrolysis, of lipid secondary messengers. Choline is a vitamin, an essential nutrient for most animal cells. Choline enters the cell through specific membrane transporters, and is phosphorylated by choline kinase, after which choline is usually activated as cytidine diphosphate (CDP)-choline (Weiss, S. B., et al. (1958) The enzymatic formation of lecithin from cytidine diphosphate choline and D-1,2-diglyceride. J Biol Chem, 231, 53-64). In the most common pathway for the biosynthesis of choline phospholipids, choline is transferred from CDP-choline to the head group of various phospholipid species, a reaction that takes place in the endoplasmic reticulum. Choline-containing phospholipids are chemically diverse, including phosphatidylcholine, sphingomyelin and ether phospholipids with a choline head group. Phosphatidylcholine is the most abundant phospholipid in most eukaryotic cells, comprising almost 50% of the phospholipid pool. Sphingomyelin is an important component of axonal myelin sheaths, making up 10% of the phospholipids in brain. Choline-containing ether lipids are less abundant, except in white blood cells, in which they reach half the level of phosphatidylcholine (Nagan, N., and Zoeller, R A. (2001) Plasmalogens: biosynthesis and functions, Prog Lipid Res., 40, 199-229), and are precursors of the platelet-activating factor (PAP), a choline phospholipid with potent inflammatory activity.
The cell biology of phospholipids is not well-understood. Progress in understanding the cell biology of choline phospholipids would be greatly aided by having the ability to metabolically label them followed by their high-resolution microscopic imaging in cells.

Compositions and methods for labeling and imaging phospholipids

President and Fellows of Harvard College


A device (10,110,210) for the expression of liquids, such as for the maintenance treatment of vascular catheters. A syringe (16; 116a,116b; 216) has a support structure (15,215) and includes at least two separate compartments (11,12; 111,112; 211,212) in which liquids for treating the lumen (L,283) of a catheter (C,280) with which the device is associated. The syringe further includes a closure plug (13,213) to be associated with the lumen being treated, which is coupled, by virtue of a releasable securement arrangement, to support structure (15,215). At least one plunger (16; 116a,116b; 216) is also included for infusing, in preset order, the different treatment liquids into the lumen to be treated, and the syringe further includes a duct (17,217) which is in fluid communication with the two compartments and is arranged through a through hole through the closure plug (13,213) in order to allow access of the treatment liquid to the interior of the lumen (L,283) upon activation of the plunger.

As is known, vascular catheters, including central venous catheters, or CVCs, are medical devices for the infusion of pharmacological substances and fluids into a vessel of a patient, for example, the inner jugular, the subclavian, and the femoral vein, and for performing extracorporeal blood circulation during hemodialysis or other procedures which require extracorporeal blood circulation. Such vascular catheters can include, depending upon the operating requirements, one or more lumens; single-lumen, dual-lumen and triple-lumen catheters are generally used.
The classical application of dual-lumen or triple-lumen catheters relates to extracorporeal circulation for performing chronic extracorporeal hemodialysis, such as for patients which chronic kidney failure, and for performing continuous renal replacement therapy, or CRRT, in critically ill patients in intensive care units. Single-lumen catheters are used to infuse drugs and liquids, to draw blood samples and to monitor pressures in certain vascular regions.
Catheters can be of two main types: temporary and permanent. Temporary catheters are those which are placed for limited periods of time in patients who have acute requirements, whereas permanent catheters are placed to ensure chronic therapies and can have a working life of over three years. Since permanent catheters must ensure higher safety due to their permanent nature, they are provided with a subcutaneous portion between the entrance into the vein and the exit from the skin, so as to minimize the possible infections to which the patient is exposed. Any manipulation of any kind of central venous catheter, if not performed in fully aseptic conditions, can expose the patient to even fatal infection, since the CVC is placed in a central vein. Maintenance of the catheters after each use in a medical procedure is therefore particularly important in order to avoid infections and dysfunctions thereof.
In addition to the problem of infection, catheters, by being in contact with blood, are in fact exposed to coagulation of the blood at the location of the openings of the lumens. Coagulation in the catheter lumen therefore causes malfunction thereof or even complete blockage of the catheter, with the consequent need to replace it in order to continue the medical therapies in progress. Currently, the lumen or lumens of the catheter, after each use, are washed by infusing physiological solution and is then medicated by infusing an anticoagulant in the lumen or lumens in order to avoid coagulation thereof, which anticoagulant expresses the physiological solution from the catheter lumens into the vasculature. The anticoagulant is subsequently evacuated by vacuum from the catheter's proximal end when next the catheter is to be used for hemodialysis. Since the anticoagulant must remain in place and must not enter the blood circulation of the patient, in order to avoid anticoagulation within the vasculature of the patient, the volume of anticoagulant applied to each catheter lumen used must match exactly the volume of the lumen used in the procedure.
Currently, health workers who close a catheter are required to perform the following procedures for each lumen of the catheter: open a sterile syringe; open the vial of physiological solution; aspirate the physiological solution into the syringe; disconnect the device connected to the lumen of the catheter, such as an infusion syringe or tubing for dialysis or for extracorporeal circulation in other medical contexts; connect the syringe; infuse the physiological solution to perform washing; disconnect the syringe; open another sterile syringe, open the vial of anticoagulant solution; aspirate the anticoagulant solution into the syringe, paying particular attention to the aspirated volume; connect the syringe to the catheter lumen; infuse the anticoagulant in the exact filling volume of the lumen; disconnect the syringe; and apply the closure plug to the catheter lumen.
As is evident from this sequence of operations, the maintenance procedure of a catheter is time-consuming and laborious. In view of the laboriousness, the risk of procedural errors on the part of an operator is obviously high. Typical errors can be, for example, the use of incorrect products in solution, the infusion of incorrect quantities, errors in connecting parts of the catheter, and so forth. In addition to the possibility of errors, which can lead to the need to remove the catheter or, in the worst case, to actions which damage the health of the patient, the time-related aspects of the operations that must be performed also have to be considered. The maintenance time of a catheter is in fact not negligible, and if it is necessary to perform this operation frequently, as in the case of a large number of patients, the total time is important and must be assessed in terms of management expense of the hospital ward.
The aim of the present invention is to solve the problems linked to the maintenance of vascular catheters as described above. It is desired to reduce the number of operations linked to the maintenance of vascular catheters. It is also desired to reduce maintenance time with respect to maintenance of vascular catheters.
It is also desired to provide a device for catheter maintenance that is easy to use, that is safe for the practitioner and reliable in operation, and is flexible in its use.
It is also desired to provide such a device that enables avoidance of infection risk and of anticoagulation phenomena in the patient.


A test fixture to expedite the testing of the resiliency of cylindrical samples including asphalt materials. The test fixture includes a frame assembly having opposed side members for engaging the curved surface of the sample whereupon at least one transducer detects changes in displacement between the side members upon diametric deflection of the sample. Additionally, or alternatively, the test fixture includes a retaining mechanism and positioning mechanism. Upon initial alignment of the test fixture, the positioning mechanism thereafter provided automatic alignment of each consecutively tested sample with the force-applying axis. The remaining mechanism provides automatic alignment and engagement of the frame assembly with each consecutive sample.

The present invention relates to a test fixture to be used in determining the resiliency of a cylindrical sample of a material, such resiliency being indicated by the diametric deflection of the sample under a dynamic load. In particular, the test fixture relates to a transducer frame engageable with the sample and to a mechanism that aligns the sample and frame for properly receiving the dynamic load along a force-applying axis. The device has particular application in measuring the resiliency of cylindrical samples of asphalt materials.
As disclosed in Schmidt, U.S. Pat. No. 3,854,328, the resiliency of a sample may be determined by applying an impulsive compressive force to the sample and measuring the resulting diametric deflection induced by the force. As Schmidt further discloses, although the transducer used to sense the deflection could be mounted on the base of a testing device, it is preferable to mount the transducer on a frame which is carried by the sample throughout the period of deflection. The transducer, then, will properly measure the diametric deflection without tangential slippage across the curved surface of the sample, as might occur were the transducer to be affixed to the base.
As shown in Schmidt, it has been customary to secure the frame to the sample by two pairs of thumb screws, one pair for engaging each of the flat end faces of the cylindrical sample. To assure proper positioning of the transducers, so that the transducers lie in a measurement plane containing the cylindrical axis of the sample, it is necessary to properly position the frame on the sample. For this purpose, a special stand has been employed into which the sample is placed and on which the frame is rested while the frame thumb screws are individually turned for engagement with the sample. However, when many samples require test, much valuable staff time is consumed by this frame orientation and engagement procedure, particularly since each thumb screw must be individually turned. Furthermore, after the frame is properly secured to the sample, each sample must then be individually oriented with the respective top and bottom loading faces so that the cylindrical axis of the sample lies substantially normal to, and aligned with, the force-applying axis, as well as parallel to the contacting edges of the loading face. Without attention to these relationships, the force-applying axis may be misaligned in relation to the frame, or the respective loading faces may be presented with variable sample surface areas during deflection, thereby distorting applied stress readings. Yet the attention that must be paid to individual orientation procedures greatly extends the test time required for each sample. To further aggravate this problem, the resiliency of any one sample is commonly measured along two axis of the sample, each perpendicular to the other, thus doubling the required set-up times.
What is required, then, is a test fixture that will measure the diametric deflection of many samples successively without a large time expenditure for individual frame and sample orientation and engagement.

H and V Materials Research and Development, Incorporated


A method and apparatus for load balancing in a wireless network is described. In one embodiment, the method comprises receiving, by at least one of the one or more controllers, from at least one of the one or more base stations, information indicative of a rate that can be provided by the at least one base station to at least one client terminal by the at least one base station when serving a group of one or more client terminals, the at least one client terminal being associated to the at least one controller; receiving, by the at least one of the one or more controllers, from the at least one of the one or more base stations, information indicative of the transmission resources provided by the at least one base station for resource allocation among the at least one client terminal by the at least one controller; and determining, by the at least one controller, based on the information indicative of the rate and the information indicative of transmission resources, information indicative of an allocation of base station transmission resources for at least one client terminal from the at least one base station.

Cellular Massive Multiple-Input, Multiple-Output (MIMO) based on reciprocity-based channel acquisition is becoming a very attractive candidate in consideration of future radio access technologies. This is due to the promise for very large increases in throughput per unit area, especially when used over dense (small cell) deployments. Massive MIMO is also envisioned as a candidate for addressing large variations in user load, including user-traffic hotspots. One challenge of such deployments is load balancing. That is, there is a challenge associating users with cells not only based on relative signal strength from each cell, but also taking into account the relative user-traffic in the vicinity of each cell with a goal to optimize network-wide performance. Load balancing is even more challenging in emerging deployments. First, load balancing is even more important with small cells, as these are inherently less planned, and thus less regular than macro deployments, with large variability in effective-area coverage. Furthermore, emerging networks are multi-tier networks comprising tiers with base stations (BSs) having vast differences in the coverage area. Indeed, load balancing algorithms need to exploit the fact that each user can be served by multiple BSs, from multiple tiers, in order to effectively balance the network load across all tiers taking into account the fact that BSs from each tier cover different areas.
Non-uniform load distribution is considered to be a major challenge in small cell networks. If the load cannot be balanced efficiently, the performance gains that are expected as a result of the increased density of network access points (due to use of small cells) may be distributed in a very non-uniform manner within the user population. Various load balancing techniques are proposed for dynamically arranging user load across small cells. These techniques are generally designed considering traditional physical (PHY) layer approaches, where one BS serves at most one user at a certain frequency and time resource. But it is well accepted now that major gains in PHY layer are expected due to MU-MIMO and especially Massive MIMO.
Conventional downlink MU-MIMO schemes have been at the forefront of investigations in the past decade. These schemes promise spectral efficiency increases by using multiple antennas at the base-station and serving multiple users simultaneously without the need for multiple antennas at the user terminals. This is achieved by using knowledge of the channel state information (CSI) between each user and the transmitting base-station. Having CSIT (CSI available at the transmitter) allows the transmitter to precode the user streams so that each user terminal (UE) sees only its own stream. Given a base station with M transmit antennas, K single-antenna user terminals can be served simultaneously, giving roughly a multiplexing gain equal to min(M, K) with respect to a system serving a single terminal.
For the transmitter to achieve this operation reliably, it needs to have sufficiently accurate CSIT, i.e., the transmitter needs to know the channels between itself and each of the users sufficiently accurately. The techniques used for acquiring CSIT fall into two categories. The first class employs M pilots (one per base-station transmit antenna) in the downlink to allow each user terminal to estimate the channel coefficients between the user-terminal's own antenna(s) and those of the base-station. This operation provides each CSI at each receiving user-terminal (CSIR) regarding the channel between each base-station transmit antenna and the user-terminal receive antennas. The CSIR, i.e., the CSI information available at each user-terminal, is then fed back to the transmitter by use of uplink transmissions to provide CSIT, i.e., CSI at the transmitting base-station. This class of CSIT acquisition schemes have two overheads: (i) a downlink pilot overhead, which scales linearly with M (then number of antenna elements at the transmitting base-station); (b) an uplink feedback overhead, responsible for making available to the base-station the channels between each user-terminal and each base-station antenna. In the case, each user terminal has a single antenna, the uplink feedback is responsible for providing to the base-station the MK channel coefficients (complex-scalar numbers), one coefficient for each channel between each user terminal antenna and each base-station antenna. Although the uplink overhead could in principle be made to grow linearly with min(M, K), with the methods used in practice this overhead grows as the product of M and K. The downlink overhead limits the size of the antenna array, M, that can be deployed. Similarly, the uplink overheads limit both M and K, as the overheads grow very fast with respect to increasing M and K.
The second class of CSIT acquisition techniques is referred to as reciprocity-based training schemes. They exploit a property of the physical wireless channel, known as channel reciprocity to enable, under certain suitably chosen (M, K) pairs, very high-rate transmission with very efficient CSIT training. In particular, pilots are transmitted in the uplink by each user (K pilots are needed, but more could be used) and the corresponding pilot observations at the base-station are directly used to form the precoder for downlink transmission. If the uplink training and the following downlink data transmission happen close enough in time and frequency (within the coherence time and the coherence bandwidth of the channel), then the uplink training provides directly the required (downlink channel) CSI at the transmitter, since the uplink and the downlink channels at the same time and frequency are the same. In this class of techniques, the uplink overheads scale linearly with K, i.e., with the number of user terminals that will be served simultaneously. These schemes are also typically envisioned as relying on TDD (Time Division Duplex) in order to allow uplink training and downlink transmission within the coherence bandwidth of the user terminal channel with a single transceiver shared for uplink and downlink data transmission.
One attractive aspect of reciprocity-based training schemes is that one can keep on increasing the size of the transmit antenna array, M, making it "Massive", without incurring any increase in the training overheads. Although with M>K, increasing M does not increase the number of simultaneously multiplexed streams, K, (i.e., K streams are simultaneously transmitted, one to each user), increasing M induces significant "beamforming" gains on each stream (which translates to a higher rate per stream), at no additional cost in training. Alternatively, increasing M allows reducing the transmit power required to yield a target rate to a user terminal, thereby allowing for greener transmission schemes. Another advantage of Massive MIMO is hardening of the user rates, i.e. with large number of antennas, the rate that a user gets does not significantly change by small scale fading. This property allows practical load balancing and scheduling techniques for Massive MIMO deployments.
This work considers instantaneous CSIT acquisition by reciprocity based training schemes. The challenge with reciprocity based training schemes is that the "compound" uplink and downlink channels at the same time and frequency are not the same. Specifically, although the uplink and downlink physical channel components are the same, each compound channel between a "source node" (responsible for transmitting an information-bearing signal from the transmit antenna) and a destination node (attached to the receive antenna) includes additional impairments due to the transmitter (the circuitry, at the transmitter) and the receiver (the circuitry, at the transmitter). When the transmitter and receiver roles are interchanged, different impairments occur at each node, thereby rendering the two compound channels non-reciprocal. There exist various calibration techniques to calibrate receivers and transmitters so that the compound DL and UL channels are approximately reciprocal. In the following, it is assumed that reciprocity is perfectly established.
Small cell deployment in heavy traffic areas, often referred to as "hot spots," is considered as a promising solution for coping with surging traffic demands. In some deployment scenarios, the small cell layer might co-exist with the macro cell layer. Another complementary promising direction towards coping with heavy traffic demands in a power- and bandwidth-efficient manner is Massive MIMO. In Massive MIMO, the number of antennas serving users is much larger than number of users being served. In downlink Massive MIMO, for instance, many users can be served at the same time either using Zero Forcing Beamforming, or even the simpler Conjugate Beam Forming, exploiting the fact that the number of users served is far smaller than the number of antennas. As the number of antennas gets large, transmission beams get sharper, thereby achieving the desired received signal level with much lower transmitted power levels. Furthermore, with large antenna arrays, the achieved user rates harden, i.e. variance in user rate due to fast (e.g., Rayleigh) fading becomes effectively negligible.
In traditional macro cells deployments, user terminals associate themselves with the macro BS with the largest power. Although variations can arise in the traffic-load of different nearby BSs, such as e.g., in the case of hot-spots, in general such variations are relatively small due to the size and planning of the cells. In the case of smaller less-planned cells, the traffic load from one small cell to the next can exhibit much larger variations. As a result, much larger variability of the load can arise across different small BSs, if users simply associate with the BS from which they receive the strongest signal. Clearly, many BSs may be over-loaded while other nearby BSs might be serving much fewer users. Fortunately, in the case of small cell deployments, many users may be able to receive signals from several BSs as there are more BSs (on average) in proximity. As a result, many recent works consider load balancing and association methods in order to make the best out of the available resources brought by small cells.
The problem of designing good load balancing and user association techniques becomes in general more challenging in cases where more than one user is scheduled at the same time and frequency resources, i.e. with multi-user transmission schemes. Indeed, the rate each user receives in the context of a multiuser transmission scheme, such as e.g., Linear Zero-Forcing Beamforming (LZFBF), depends not only on the user's own channel, but also on the number of other users scheduled together with the user for such multiuser transmission as well as the channels of these users. The problem of scheduling user sets to maximize the sum of user rate when LZFBF precoding is applied has been considered, and a greedy algorithm for the user selection when considering a single cell with a single BS has been proposed. A technique in has been used as a building tool to schedule cellular and cluster MU-MIMO transmissions in cellular networks applying proportional fairness at each BS. These techniques can also be systematically expanded to include a broader range of fairness conditions with the framework of virtual queues in.
All of the above scheduling methods are local, in that they assume that user to BS association has already taken place, so that the fairness framework can be applied locally at each BS. Predicting a priori the effect that different user-BS associations have on the network-wide fairness provided across the network by these "locally fair" schedulers is in general non-trivial. However, when the number of antennas at the BS is much larger than the number of users instantaneously served by a BS in each transmission resource element, the instantaneous user rates "harden" (show much lower variability) and can be accurately predicted by just knowing the size of the serving set at the BS.
Reciprocity-Based Massive MU-MIMO
Consider the problem of enabling MU-MIMO transmission from an array of M transmit antennas to U single-antenna user terminals. The downlink (DL) channel between the i-th base-station transmitting antenna and the k-th user terminal is given by{right arrow over (yki)}={right arrow over (hki)}{right arrow over (xi)}+{right arrow over (zki)}where {right arrow over (xi)}, {right arrow over (hki)}, {right arrow over (yki)}, {right arrow over (zki)} denote the transmitted signal from base-station antenna i, the compound DL channel between the two antennas, and the observation and noise at the receiver of user terminal k, respectively. This model is applicable at any resource block. In general, the variables in the above equation are resource-block dependent. This dependency is currently ignored in the notation for convenience though with an abuse of notation, it will be used when time-sharing across various resource blocks are considered. The amplitude and phase shifts introduced by RF-to-baseband conversion hardware (e.g., gain control, filters, mixers, A/D, etc.) at the receiver of user terminal k as well as the amplitude and phase shifts introduced by the baseband-to-RF conversion hardware (e.g., amplifiers filters, mixers, A/D, etc.) at the transmitter generating the signal to be transmitted by base-station antenna i are all included in the DL compound channel.
Similarly the uplink channel between the k-th user terminal and the i-th base-station antenna is given by=+where , , , , denote the transmitted signal from user terminal k, the compound uplink (UL) channel between the two antennas, the observation and noise at the receiver of base-station antenna i, respectively. The amplitude and phase shifts introduced by RF-to-baseband conversion hardware (e.g., gain control, filters, mixers, A/D, etc.) at the receiver of base-station antenna i as well as the scalar (complex) coefficient  contains the amplitude and phase shifts introduced by the baseband-to-RF conversion hardware (e.g., amplifiers filters, mixers, A/D, etc.) at the transmitter generating the signal to be transmitted by user terminal k are all included in the compound UL channel.
In the uplink, the following model may be used:=+where  is the vector of dimension K×1 (i.e., K rows by 1 column) comprising the user symbols on subcarrier n at symbol time t,  is the M×U channel matrix that includes the constant carrier phase shifts and the frequency-dependent constant in time phase shifts due to the relative delays between the timing references of the different terminals,  and  are the received signal vector and noise at the user terminal.
In the downlink, the following model may be used:{right arrow over (y)}={right arrow over (x)}{right arrow over (H)}+{right arrow over (z)}where {right arrow over (x)} is the (row) vector of user symbols on subcarrier n at symbol time t, {right arrow over (H)} is the U×M channel matrix that includes the constant carrier phase shifts and the frequency-dependent constant in time phase shifts due to the relative delays between the timing references of the different terminals, {right arrow over (y)} and {right arrow over (z)} are the received signal (row) vector and noise at the user terminals. Other BSs at sufficiently close distance cause interference as network MIMO/joint transmission/CoMP or any other interference mitigation techniques are not considered. Interference from the other access points is included in the noise term.
Assuming perfect calibration, the compound UL and DL channels become reciprocal, so that={right arrow over (H)}
For simplicity, the thermal noise is neglected. In order to estimate the downlink channel matrix, the U user terminals send a block of U orthogonal frequency division multiplexing (OFDM) symbols, such that the uplink-training phase can be written as=+noisewhere  is a scaled unitary matrix. Hence, the base-station can obtain the channel matrix estimate=+noise
In order to perform downlink beamforming, the compound channel downlink matrix {right arrow over (H)} is used.
The ZFBF precoding matrix is calculated asW=Λ1/2[{right arrow over (H)}H{right arrow over (H)}]−1{right arrow over (H)}H where Λ is a diagonal matrix with λm's as diagonal elements that imposes on each row of the matrix W, the row normalization ∥wm∥2=1, for all m.
Hence, the ZFBF precoded signal in the downlink with equal power for each beam also taking account a distance-dependent pathloss model with the diagonal matrix matrix G, whose diagonal elements are gi's.
                                          y            →                    =                                                                        u                →                                                          p                                  1                  /                  2                                                                          G                                  1                  /                  2                                                          W                                            H                →                                      +                          z              →                                                                    =                                                                        u                →                                                          p                                  1                  /                  2                                                                          G                                  1                  /                  2                                                                                Λ                                          1                      /                      2                                                                                [                                                                                H                          →                                                H                                                                                H                        →                                                              ]                                                                    -                  1                                                                                H                  →                                H                                                          H                →                                      +                          z              →                                                                    =                                                                        u                →                                                          p                                  1                  /                  2                                                                          G                                  1                  /                  2                                                                          Λ                                  1                  /                  2                                                      +                          z              →                                                      λ      k        =          1                        [                                    (                                                                    H                    →                                    H                                                                  H                  →                                            )                                      -              1                                ]                          k          ,          k
Notice that the resulting channel matrix is diagonal, provided that S≦M.
Prior Art on MU-MIMO User Scheduling
Although there several methods available in the literature for scheduling multi-user MIMO transmissions at the BS, a widely accepted class of methods involves scheduling policies which, at any given scheduling instant at the BS, schedule the subset of users that would yield the highest expected weighted sum-rate. Each user's expected rate in each scheduled set for transmission is a function on the instantaneous channels of all the users in the scheduled set. Indeed, assuming LZFB transmission as described in the preceding section, at any given resource block the coefficients λk's depend on the instantaneous channel matrix of all users in the scheduling set (served by ZFBF), and in particular, they can be expressed as
                    λ                  k          ,          S                                  (        t        )              =          1                        [                                    (                                                                                H                      →                                                              k                      ,                      S                                        H                                                                          (                    t                    )                                                                                H                      →                                                              k                      ,                      S                                                                                (                    t                    )                                                              )                                      -              1                                ]                          k          ,          k                      ,where {right arrow over (H)}k,S(t) denote the compound downlink channel matrix for UEk in the user set S at the t-th resource block. Clearly, since the choice of the user set S and/or resource block (t) affects λk, the expected user rates are a function of both the scheduling set and the instantaneous channel realization. Fixing the scheduling time instance, and assuming LZFBF transmission, the problem of choosing the subset S which maximize the weighted sum-rate is combinatoric in the number of antennas, as the number of possible subsets, S, that can be considered for scheduling grows exponentially fast with the maximum number of users that can be considered for joint scheduling. One solution to this problem has been proposed that relies on a greedy algorithm for user set selection, with at most quadratic complexity.
Another important factor defining the scheduling assignments that are produced by the scheduling policy is the method by which the "user weights" are chosen at each scheduling instant prior to performing the weighted sum rate maximization operation. Although many methods exist for choosing these weights, a widely accepted class of methods (because of their ability to result in nearly optimal performance with respect to a fairness criterion belonging to a broad class of fairness criteria) is one that relies on the use of "virtual queues" to determine the instantaneous user-weights in the weight-sum rate optimization.
Prior Art on Load Balancing
Traditionally, association in cellular networks has been user-terminal based. Users measure their signal-level with respect to the beacons of the nearby BSs and associate to the base-station with the strongest received signal. A generalization of this principle has been used in heterogeneous networks. In the case of comparing signal strengths from a macro and a small cell, a user-terminal can also apply a "bias" to favor association to the small cell (with respect to the macro cell).
As traffic-load imbalances are far more pronounced in small cells, there has been some recent work in load balancing in small cells. Indeed, small cells are much more sensitive to the cell association policy because of the non-uniformity of cell size, and the smallest average number of users they serve. This non-uniformity can result in extremely imbalanced traffic-load based on a max-SINR cell association. The prior art in this area mainly involves methods of exchanging information between each user and nearby BSs, which attempt to balance their load using signaling exchanges with nearby users. Another related technique, referred to as "cell breathing," relies on dynamically changing (contracting or expanding) the coverage area depending on the load situation (over-loaded or under-loaded) of the cells by adjusting the cell transmit power. Also note that these works focus on small cells scheduling only single-user transmissions.
Limitations of the Previous Works
The methods described above have important limitations. First, given that the user rates in a MU-MIMO, transmission are not simply a function of large-scale signal-to-interference plus noise ratio (SINR), but in general depend on the scheduling set and the channel realization, the resulting load-balancing techniques are not extendable in any straightforward resource-efficient manner. Furthermore, the nature of reciprocity-based Massive MIMO TDD makes large scale SINR in a link between a user and all BSs in proximity available given a single uplink pilot broadcast from the user. In this context, the association (if any) of a user to a BS can be performed by centralized processing among the BSs without involving exchanges with the users. Using a central controller to fully perform load-balancing among the BSs as well as schedule transmission at each of the BSs is, however, computationally intractable.
Techniques for load balancing and scheduling by use of a combination of processing and information sharing between a central controller and a set of BSs have been put forth. The methods leverage properties of "massive MIMO" type transmission to enable achieving near-optimal scheduling and load-balancing performance in Massive MIMO cellular transmission. These methods are suitable for performing load balancing by use of a central controller balancing the load across a group of base-stations. However, these techniques are not readily area-scalable as they rely on a single central controller allocating resources over the network over which load balancing is performed. To illustrate the fact that these schemes are not readily scalable, assume for a moment that the average density of the BSs, and user-populations is fixed. Increasing the area over which load balancing is performed results, at best, in a linear increase of the number of optimization variables with coverage area. This is because increasing the coverage area results in a linear increase in the number of users that need to be associated with the various base-stations covering the area. Hence these techniques are limited to balancing the load in a given, confined, geographical area.

Method and apparatus for scalable load balancing across wireless heterogeneous MIMO networks


A hub assembly for pivotally holding the ends of the column-like support rods which make up the skeletal frame of a collapsible, self-supporting structure, comprising extension caps for the ends of the support rods, a circular hub body with retaining slots or sockets which receive and pivotally hold the ends of the extension caps and a circular locking disk which releasably interlocks with the hub body to retain the ends of the extension caps in pivotal relationship within the hub body.

This invention relates to collapsible self-supporting structures, and more particularly to a hub assembly for pivotally holding the ends of the column-like support rods which make up the skeletal frames for such collapsible structures.
The collapsible structures have network support rods which are pivotally joined together for movement between a collapsed, compact position for storage or transportation and an opened condition in which the desired structural shape is attained. Dome or arch shape structures of this type may be illustrated by U.S. Pat. Nos. 3,838,703, 3,968,808, 4,026,313, and 4,290,244. Collapsible display frame structures of the type having planar or arcuate face surfaces may be illustrated by U.S. Pat. Nos. 4,276,726 and 4,471,548. Such display frames are commercially available and are useful in setting up for trade show displays and the like.
The above-mentioned patents show various hub assembly structures for pivotally holding the ends of the support rods. Also, U.S. Pat. No. 4,280,521 specifically shows a multiple-bodied hub to be fused together to capture a ring and interconnected blades which extend from the support rod ends. These hub assemblies are characterized by having multiple parts that are typically designed to be permanently assembled together.
Because of the complex nature of the network of support rods, the hub assemblies must accommodate complex movements between the collapsible structure's opened and collapsed positions. Some twisting, flexing, and straining between the hub assemblies and support rods are inherent in such structures. Additionally, with repeated opening and collapsing of the structures typically used for trade show displays, the hub assemblies are subject to wear and may break rendering the entire collapsible structure useless. Replacement or repair of a hub assembly or a support rod may be impossible or difficult in addition to being time consuming. Therefore, such replacement or repair has generally been considered not feasible for many of the aforementioned structures.


A machine for removing old rails and replacing them with new rails is constituted by an adzing station where the surfaces of the old ties are adzed after removing the old rails and tie plates. The adzing station has two adzers spaced laterally on either side of the center of the machine for adzing laterally spaced locations at which new tie plates and rails have to be laid. The adzers are mounted, respectively, on two frames which can move together laterally with respect to a third frame in response to a center line follower so that the adzers are always located at the correct lateral position even on curved track. The third frame is attached to the main frame of the machine and it can be pivoted selectively about two spaced lateral locations adjacent to where the adzers are mounted in response to control signals from an inclinometer mounted on the pivotal frame and control signals from a superelevation device measuring the superelevation of the track. Thus the adzers are maintained substantially perpendicular to the ties for all conditions of cross-level including superelevation on curves.

This invention relates to a machine for adzing old ties on track from which the tie plates and rails have been removed, and also to a rail changing machine incorporating such an adzing arrangement.
Devices for changing rails which have existed to date have been hampered in operation by the great number of auxiliary operations which have to be performed by different workcrews using different machines.
It is an object of the present invention to provide a rail changing machine which, in its preferred embodiment, is capable of replacing rails without any additional operations being necessary.
The present invention makes use of a novel adzer support which is pivotable with respect to the main frame of the machine and about a pivot point which coincides approximately with one laterally disposed adzer or about a pivot point which coincides approximately with the other laterally disposed adzer as selected. By this means the adzers may be maintained substantially perpendicular with respect to superelevated or banked ties which are provided at curves and, of course, the frame is pivotal in either direction to accommodate right or left curves.
As an additional feature the degree of tilting is measured automatically and fed back to a device for measuring the superelevation of the track, whereby the adzers are automatically maintained at the correct angle.
Preferably, the adzers are also mounted for conjoint lateral movement on the pivotal frame in response to signals from a centre line follower which follows a previously applied track centre line. This additional feature permits the adzer station to be accommodated on a long work beam on which are mounted other work stations because on curved track the adzers are simply moved laterally to the correct rail location.


A device 1 for engaging and disengaging rollers rollers 14, 15, which are arranged horizontally in pairs, with the shaft ends 18 of the upper rollers being provided with ball bearings 6 which can be lifted and lowered and are guided in bracket-type guides 7. The webs 3, 4 of U-shaped slide members 17 are guided in friction bearings 2, and said slide members can be shifted to and fro by a shifting path X. The webs 3, 4 are provided with recesses 9, 10, each of which possesses a bevelled edge 5a, 5b. The ball bearings 6 roll along the bevelled edges such that in the engaged position the ball bearings are pressed down in the guides 7 by the upper edges 5b, and in the disengaged position they are raised by the lower edges 5a. The recesses 9 provided in the lower web are staggered with respect to the recesses 10 provided in the upper web 4 by the shifting path X. Each slide member 17 is equipped with a gear rack 11 engaged by a gear wheel segment 12, which by use of a swivelling lever 16 can be swivelled about a shaft 13 supported in the side plate 20. The lower rollers 14 are stationarily supported in the side plates 20.

The present invention relates to a device for engaging and disengaging rollers, comprising pairs of upper and lower horizontal rollers. The rollers convey sheet-like materials and squeeze off any residual liquid adhering to the sheet-like materials. A bearing which can be raised and lowered with respect to the lower roller, is provided at the axial ends of each upper roller.
A device of this kind has been disclosed by German Offenlegungsschrift No. 2,326,122, in which each shaft journal of a pair of upper and lower rollers extends into a housing on each side. In this arrangement, the lower bearing is fixed, whereas the upper bearing is free to pivot on a pin arranged eccentrically relative to the axis of the upper bearing. The side of the bearing opposite to the pin is connected with a joint. The joint, in turn, is hinged to the lower end of a lever which is adapted to swivel about a horizontal pin mounted in a bracket attached to the upper wall of the housing. An actuating handle projecting from the top of the housing is connected with the swivelling lever. The lever and the joint constitute a toggle lever arrangement which forces the upper rollers against the lower rollers when the arrangement is in the extended position, and which raises the upper rollers from the lower rollers when the actuating handle is shifted. A relief spring ensures that the upper rollers are arrested in the raised position.
Each end of each upper roller is provided with a separate actuating lever. It is therefore necessary, using this device, to actuate quite a number of handles to raise the upper rollers. Raising the rollers is required prior to any prolonged standstill, for example, overnight or for the weekend, in order to prevent the upper rollers from sticking to the lower rollers. This is a time-consuming operation, so that the operator is tempted to omit it at times. If, however, the rollers are left pressed together, the rollers may stick together, as described above, and, moreover, deformations of their surfaces may occur. Such deformations may jeopardize a safe and gentle transport of the sheet-like materials, in particular of printing plates, and a complete squeezing off of liquid from the sheet-like materials particularly in horizontal processing equipment.
In order to facilitate the operation of a developing device for printing plates, European Pat. No. 0,004,337 (equivalent to U.S. Pat. No. 4,206,527) proposes a device, in which a pivoting fork head having an upper and a lower arm is provided for engaging the bearings of the upper rollers. The pivoting axis of the fork head extends parallel to the direction of transport of the printing plates. The bearings are actuated via a toggle lever arrangement, whereby the upper arm of the pivoting fork head exerts pressure on the top of the bearing when the bearing is in a lowered position, and the lower arm of the fork head supports the bearing in a raised position. A first end of each toggle lever arrangement is connected with the fork head. A second end of each toggle lever arrangement is connected with a rotatable control shaft which is common to all toggle lever arrangements, and supported parallel to the direction of transport of the printing plates. It is true that in employing this device it is possible to raise and to lower all upper rollers by one single lever actuation, but the construction of the toggle lever arrangement and the forked heads equipped with two arms is complicated and expensive.
There has also been disclosed an apparatus for developing printing plates, which comprises rollers which are arranged in pairs and the ends of which are supported in side plates. These side plates are divided into upper and lower parts, and the upper part of each side plate is pivoted and equipped with the corresponding lifting elements in such a manner that the complete upper parts of the side plates or the upper part of the processing station, respectively, may be lifted together with all upper rollers.
This latter apparatus is also comparatively expensive, particularly if the effort which must be exerted by the operator for the lifting operation is to be kept moderate. In addition, the above arrangement cannot be used in an installation including a number of component processing stations which may be assembled, in a modular manner, with other structural units to form the complete installation.


A catalyst system that converts the exhaust gas of a compressed natural gas (CNG) fueled automotive engine when operated at stoichiometry or slightly lean thereof, at highly enhanced rates, and having: (a) a first stage catalyst comprising a transition metal-containing zeolite (Cu-ZSM5), and (b) a second stage catalyst for treating the effluent of the first stage and comprising palladium supported on high surface area gamma alumina. The second stage catalyst has the alumina support impregnated with an intimate mixture, by weight, of 0.5-20% La.sub.2 O.sub.3 and 0.2-30% palladium.. A method of treating exhaust gases from a CNG-fueled engine, comprising: (a) operating the engine at stoichiometry or slightly lean (0.85-1.0 R) thereof; (b) exposing such exhaust gases to a first stage catalyst consisting of a copper-ZSM5 zeolite having at least 3% by weight ion exchange copper; and (c) exposing the effluent from the first stage to a second stage comprising a gamma alumina support catalyst impregnated with palladium and other catalyst enhancing oxides.

1. Technical Field
This invention relates to the technology of catalytically converting emissions of a compressed natural gas (CNG) fueled engine, and more particularly to the technology for converting such exhaust gases when the combustion process for such engine is operated at or slightly lean of stoichiometry.
2. Discussion of the Prior Art
Natural gas (essentially 85% methane) is an attractive source of fuel for vehicles because it provides for a lower fuel cost, longer engine life, lower maintenance, and reduced oil consumption. Development of catalysts for high efficiency removal of saturated hydrocarbons, which includes methane, by oxidation within an exhaust stream is of strategic importance; it may be crucial in view of the emission control requirements promulgated by the U.S. Government. In the past, oxidation of methane has received little attention in automotive catalysis. Extreme difficulty of removal of methane is experienced because a C--H bond must be ruptured. In the oxidation of higher alkanes, oxidation is easily achieved by cleavage of C--C bonds. Since the C--H bond is stronger, methane is more difficult to oxidize.
In copending U.S. Ser. No. 07/772,318, filed Oct. 7, 1992 authored by some of the authors of this invention and commonly assigned to the assignee herein, a catalyst is disclosed which enhances the three-way conversion capability of a modified Pd/Al.sub.2 O.sub.3 catalyst in treating the exhaust gas of a compressed natural gas-fueled engine, provided the engine is limited to being operated slightly rich of stoichiometry, i.e., 1.1-1.2 R (R being the ratio of reducing components to oxidizing components in the exhaust gas). Although this is a significant achievement over the prior art, fuel-rich operation affects the fuel economy of operating the CNG fueled engine and therefore can be undesirable. At stoichiometry or below, the conversion capability of such catalyst drops dramatically.
Zeolite catalysts have been found useful for converting nitric oxide contained in the exhaust of a conventional gasoline-fueled engine, particularly when the combustion process is lean (possessing a high excess oxygen content in the exhaust gas). One of the earliest applications of high silica zeolites to the purification of a conventional gasoline-fueled engine exhaust is disclosed in U.S. Pat. No. 4,297,328, wherein a copper-exchanged zeolite is deployed. Copper is most effective as the ion exchange metal because it is more active at lower temperatures than other metals known to date. Such catalyst performed only in an oxidizing environment.
U.S. Ser. No. 07/753,780, filed Sep. 3, 1991, authored by some of the inventors herein and commonly assigned to assignee of this invention, disclosed a modification to such catalyst to prevent it from degrading at high temperatures, usually found in automotive exhaust systems, and to enhance the catalytic activity of copper-exchanged zeolites. Such prior art knowledge has not extended to the use of zeolites for conversion of exhaust gas of a compressed natural gas engine nor to the use of such catalyst when the engine is calibrated at stoichiometry or slightly lean thereof. This is an important differentiation because the exhaust gas from a conventional gasoline-fueled engine will contain considerably more hydrocarbon (HC), nitric oxide (NO), carbon monoxide (CO) concentration compared to the exhaust gas from a CNG-fueled engine (see Table I). Therefore, the ability of a zeolite catalyst to provide any successful degree of conversion for a CNG-fueled engine has not been envisioned and likely would not operate properly based upon data to date.

Treating exchaust from a compressed natural gas-fueled engine


An antenna tracking control device includes detectors for detecting speed and the steering angle of a movable body, a device for calculating the estimated azimuth angle of the movable body based on the detected speed and steering angle, and a detector for detecting the azimuth angle of the movable body. Also, an azimuth angle error estimator is provided for calculating the error between the calculated estimated azimuth angle and the detected azimuth angle. In addition, a directing angle error detector is used for detecting antenna directing angle error, and a directing angle error corrector is used for correcting the detected antenna directing angle error, with the result that the antenna tracking control device causes an antenna mounted on a moveable body, such as an automobile, to track a wave generating source based on the corrected antenna directing angle error.

The present invention relates to a control device for directing an antenna disposed on a movable body such as aircraft, vehicles, ships or the like to a wave generating source.
In satellite communication systems using an antenna disposed on movable body, the antenna is controlled to track the satellite under consideration of the movable body's location and change of the movable body's attitude, since it is necessary at all times to direct the antenna to the satellite.
As a prior art for antenna tracking control described above, an invention disclosed in Japanese Patent Laid-Open No. 271182 (1988) is explained below.
FIG. 5 is a block diagram showing an example of a body tracking control device of antenna loaded on movable body. Where, 51 is an antenna, 52 is an antenna directing angle error detector, 53 is a movable body azimuth angle detector, 54 is an antenna directing angle error corrector, 55 is an antenna tracking controller and 56 is an antenna driving motor.
First of all, the antenna directing angle error detector 52 calculates a difference between satellite direction and antenna beam direction, that is, antenna directing error and outputs an antenna directing angle error signal x.
On the other hand, the movable body azimuth angle detector 53 detects azimuth angle of the movable body and outputs a movable body azimuth angle signal y.
The antenna directing angle error corrector 54 inputs the antenna directing angle error signal x and the movable body azimuth angle signal y, corrects the antenna directing angle error signal x using the movable body azimuth angle signal y and outputs an antenna directing angle error correction signal z.
Then, the antenna tracking controller 55 controls the antenna driving motor 56 to direct the antenna 51 to the satellite, based on the antenna directing angle error correction signal z.
Providing for a case that the antenna directing angle error detector 52 cannot detect the antenna directing angle error signal x, a number of satellites' orbit data, as well as the antenna directing angle error signal x, are prepared in advance for the antenna tracking controller 55.
Only when input of the antenna directing angle error signal x is stopped, the antenna tracking controller 55 controls the antenna driving motor 56 using a pseudo antenna error signal generated from the satellites' orbit data and the movable body azimuth angle signal y.
In the above-mentioned art for controlling tracking of antenna loaded on a movable body, however, detection of azimuth angle of a movable body when the movable body changes advancing direction is delayed in the movable body azimuth angle detector 53. If the movable body is an automobile, for example, at the time when the handle is operated to steer tires, azimuth angle of the automobile is not changed yet because the automobile does not move enough. Therefore, it is not possible at this time to anticipate and detect advancing azimuth angle of the automobile.
In this system, if the antenna directing angle error signal x is corrected using the azimuth angle detected by the movable body azimuth angle detector 53, it is not possible to correct it without any time lag due to time needed for correction processing, etc.
In addition, antenna tracking response speed of such an art is limited by a dead time of the antenna tracking controller 55 and a time lag in the antenna directing angle error detector 52.

Tracking control device of antenna loaded on movable body and tracking control method of the antenna


A dielectric interlayer is formed over a semiconductor substrate comprising at least one active region. The exposed upper surface of the dielectric interlayer is treated with nitrogen to form a nitrided barrier layer thereon. At least one hydrogen-containing dielectric layer is formed over the dielectric interlayer having the nitrided barrier layer thereon. The nitrided barrier layer serves as a barrier to diffusion of hydrogen from the at least one hydrogen-containing dielectric layer into the dielectric interlayer, thereby preventing a decrease in hot carrier injection reliability.

The escalating demands for high densification and performance associated with ultra large scale integration semiconductor devices require design features of 0.25 micron and under, such as 0.18 micron, increased transistor and circuit speeds, high reliability and increased manufacturing throughput. The reduction of design features to 0.25 micron and under generates numerous problems challenging the limitations of conventional technology, including conventional photolithographic, etching, and deposition techniques.
Conventional methodology for forming patterned metal layers, as part of "back-end" wafer processing, comprises a subtractive etching or etch back step as the primary metal patterning technique. Such methodology involves the formation of a first dielectric interlayer on a semiconductor substrate, typically doped monocrystalline silicon, with conductive contacts formed therein for electrical connection with an active region in or on the semiconductor substrate, such as a gate oxide or a source/drain region. A metal layer, such as aluminum or an aluminum alloy, is deposited on the first dielectric layer, and a photoresist mask is formed on the metal layer having a pattern corresponding to a desired conductive pattern. The metal layer is then etched through the photoresist mask to form the conductive pattern comprising metal features separated by gaps, such as a plurality of metal lines with interwiring spacings therebetween. A dielectric material, such as spin-on glass (SOG) is typically deposited to fill in the gaps between the metal features and baked at an elevated temperature. The baking time is determined depending upon the particular material employed. Thereafter, another dielectric layer is deposited thereover, such as a silicon oxide derived from tetraethyl orthosilicate (TEOS) by plasma enhanced chemical vapor deposition (PECVD). Planarization, as by chemical-mechanical planarization (CMP), is then performed.
The drive to increased density and attendant shrinkage in feature size generates numerous problems. For example, as feature sizes, e.g., metal lines and interwiring spacings, shrink to 0.50 micron and below, such as 0.375 micron, it becomes increasingly difficult to satisfactorily voidlessly fill in the interwiring spacings with a dielectric material and obtain adequate step coverage.
Hydrogen silsesquioxane (HSQ) offers many advantages for use in back-end wafer processing. HSQ is relatively carbon free, thereby rendering it unnecessary to etch back HSQ below the upper surface of the metal lines to avoid poisoned via problems. In addition, HSQ exhibits excellent planarity and is capable of gap filling interwiring spacings less than 0.30 micron while still employing conventional spin-on equipment. HSQ undergoes a melting phase at approximately 200.degree. C., but it does not convert to the high dielectric constant glass phase until reaching temperatures of about 400.degree. C. in intermetal applications. As deposited, HSQ is considered a relatively low dielectric constant ("low k") material with a dielectric constant of about 2.9-3.0, compared to silicon dioxide grown by a thermal oxidation or chemical vapor deposition which has a dielectric constant of about 3.9-4.2. The mentioned dielectric constants are based on a scale wherein 1.0 represents the dielectric constant of air.
Other hydrogen containing low dielectric constant materials suitable for use as gap filling and/or cap layers in back-end wafer processing include but are not limited to methyl silsesquioxane (MSQ) and other organic low k materials.
However, in attempting to apply a hydrogen-containing low k material, such as HSQ, to "back-end" wafer processing as described above, particularly for gap filling, it was found that the hydrogen contained therein undesirably diffuses into the underlying dielectric interlayer during its deposition and/or during subsequent processing. Such hydrogen diffusion into the dielectric interlayer overlying active device regions formed in or on the substrate adversely affects hot carrier injection reliability which, in turn, reduces or deleteriously affects device performance.
In addition, deleterious hydrogen diffusion into the dielectric interlayer may also result upon formation and/or subsequent processing of a hydrogen containing oxide "cap" layer typically deposited over the dielectric layer prior to metal pattern formation and gap filling.
There exists a need for semiconductor technology enabling the use of low dielectric constant gap fill layers, such as HSQ, without adverse impact on hot carrier injection reliability.

H2 diffusion barrier formation by nitrogen incorporation in oxide layer


A golf club shaft including a damping layer which serves to reduce the amplitude of vibrational waves subject upon a golf club shaft is provided. The damping layer which includes, at least in part, an elastomeric material is coated to the inner diameter of the golf club shaft along a desired length. A method is also provided which relates to reducing the effects of induced modes of vibration upon a golf club shaft.

The present invention relates to shafts and, more particularly, to tubular shafts in which induced modes of vibration subjected upon the shafts are carefully controlled.
By way of example, one form of tubular shaft which is contemplated as on a golf club.
Golf clubs are typically assembled to include a club shaft having selected performance characteristics and a club head having matching or complementary performance characteristics. A number of factors must be considered in the design of the club head and the club shaft to assure optimal performance when hitting the golf ball. Many of the design factors for both the club head and the shaft are related to dimensional and static mass characteristics. For example, principal club head design parameters include the overall mass, the club face angle and surface characteristics, the dimensional envelope, and the location of the center of gravity. Similarly, principal club shaft design parameters include the length of the shaft, its diameter, the change in shaft diameter with length, the overall mass, and its flex characteristics.
Additionally, attention in the design and manufacture of golf club shafts has been focused on the flex and torsional damping characteristics of the golf club shaft since it has been discovered that the so-called damping characteristics have a direct and primary role in determining the "feel" of the golf club during impact.
With regard to use of the golf club, the golf club stroke can typically be divided into separately defined portions, namely the takeaway, the backswing, the downswing, impact, and the follow through. During the takeaway, the golf club is taken back to set up that portion of the swing generally known as the downswing somewhat to cause the club head to lag behind the shaft. As the downswing is initiated, the direction of the shaft movement and that of the club head is reversed with the club head lagging or following the shaft. The amount of club head lag is a function of the shaft stiffness and the torque applied to the shaft during downswing. Since the club head is on the distal end of the shaft during the downward acceleration, the club head accelerates more quickly than any other point along the shaft and, for most shafts, the club head will lead the shaft at some point in the downswing prior to impact. Because of the flexibility of the shaft, the club head has downswing flight characteristics somewhat akin to an object in tethered flight.
Among the consequences of these club head flight characteristics prior to impact are small changes in the angular relationships of the club face in relation to the longitudinal axis of the unflexed shaft. These angular changes affect the engagement of the club face with the ball at impact and, therefore, the subsequent flight path of the ball. During impact, the golf ball is compressed to define a contact area between the club face and the compressed surface of the golf ball through which a portion of the momentum of the club head is imparted to the ball. The time of actual contact between the club face and the golf ball is generally on the order of approximately 450 to 600 microseconds. As a result of the club head contacting the ball at impact, traverse and torsional vibrational waves are induced which travel upwardly along the length of the shaft toward the grip. For purposes of the present invention, "torsional vibration" is defined as the oscillatory displacement about the longitudinal axis of the shaft and "transverse vibration" is the oscillatory displacement occurring perpendicular to the longitudinal axis of the shaft.
As a consequence of the momentum transfer at the club face to the ball during impact, the shaft is flexed rearwardly so that the club head again lags behind and follows the shaft. After impact and during follow through, the club head oscillates between lagging and leading positions as a consequence of the natural frequencies of the shaft, these oscillations including several modal orders above the lowest order.
In an effort to enhance the "feel" of the golf club, golf shafts have been developed which are formed of composite fibers in which the shafts are fabricated from oriented non-metallic fibers, i.e., graphite, boron, glass, etc., in an epoxy matrix. For example, graphite shafts typically include an inner lamina fabricated with fibers that are oriented at complementary angles to the longitudinal axis of the unflexed shaft, e.g., +45.degree. and -45.degree., to provide a measure of torsional stiffness, and an outer lamina fabricated with fibers that are substantially parallel to the longitudinal shaft axis to provide longitudinal stiffness. Typically, graphite shafts and composite shafts in general, have a somewhat "damped" feel wherein the effects of high vibrations along the shaft are less traumatic. The longitudinal stiffness can be controlled by varying the size and number of longitudinal fibers, and the torsional stiffness can be varied by controlling the angularly oriented fibers to provide a measure of independence between the two characteristics, sometimes it can be difficult.
In an effort to achieve a better "feel" still further developments in the art have focused on selectively damping golf club vibrations by controlling vibrational frequencies through the use of devices disposed along various lengths of the golf club shaft. Typically, such devices have included disposing sleeve-like members including a first layer of elastomeric material and a second layer of a metallic material about the inner or outer surface of the shaft as disclosed in U.S. Pat. No. 5,249,119 which issued Mar. 15, 1994, to Vincent et al.
The need for golf club shafts which offer isotropic material properties and which posses the internal damping characteristics seen, for example, in composite golf club shafts is readily apparent. By "isotropic," it is meant that the shaft to which the dampening material is applied will essentially have the same strength and elastic properties in all directions (i.e. similarities along the length of the shaft with regard to the modulus of elasticity, modulus of rigidity and Poisson' ratio). As a consequence of this isotropic effect, shafts and, more particularly, steel shafts are more consistent over a spectrum or set and allow for a tighter dispersion of shots.