An actuator control system is disclosed that includes an actuator continuously movable between multiple positions. The controller is configured to command the actuator to a desired actuator position and to apply the command to an actuator model. The controller is configured to compare the modeled and actual actuator positions to determine if the position difference exceeds a fault detection accommodation limit and if the position difference is within a band that is different than the fault detection accommodation limit. The controller is configured to calculate a threshold, which is based upon an estimated load on the actuator. The controller is configured to calculate a band comprised of the threshold applied to the modeled position and to determine if the actual actuator position is within the calculated band. The threshold is calculated at regular intervals, and a fault is declared if the actual actuator position is outside the band for a number of consecutive intervals.

This disclosure relates to an actuator for use in an aircraft, for example. More particularly, the disclosure relates to an actuator health monitoring system and method.
Electro-hydraulic actuators are used in a number of aerospace applications to translate electrical commands into motion. This motion may be used to move aerodynamic control surfaces, adjust fuel and/or airflow, and the like. Because the proper operation of these actuators is critical to the operation of the system (e.g. aircraft, engine, etc.), it is critical to know the health of the actuation system.
Control systems are designed to be failure tolerant. If a failure is detected, the system is designed such that there is an accommodation that can be taken, either switching to an identical backup system, or other similar mitigation. In the case of flight critical systems, the detection of such faults must be made quickly, usually in a matter of milliseconds. A method commonly used in the art is an open loop failure detection scheme. In this scheme, the actuator position (from a position measuring device) is compared to the commanded position. The actuator is declared failed if the actuator does not move to the commanded position within the designated time frame. Otherwise, it is declared good. There may be a simple actuator model used to improve the fidelity, which is typically termed fault detection and accommodation (FDA), and is well known in the art.
In order to reduce the false alarm rate, the thresholds for this check are usually quite high. This is due to a number of factors. Since the FDA logic is calculated at a high rate, the actuator will not move very much between calculations, so position sensor accuracy and resolution can become large errors. These measurement errors magnify other error sources, such as mechanical loading on the actuator, normal tolerances, etc. In order to have an acceptably low failure rate, the fault threshold has to be set low in order to account for these errors. Typically the actuator has to be running at 50% or less of its normal speed to be declared failed by FDA.
There are many failure modes of actuators and actuation systems that provide advanced warning, such as seal leakage, shorted torque motor coils, binding linkages, abnormally increased loads, clogged hydraulic filters, etc. These failure modes would present themselves as the actuator running at slower than normal speed. It would be useful to be able to reliably detect actuators that were operating in the less than normal but above FDA limit (50%) range in order to replace these actuators or otherwise address the faults, before advancing to the failed state that requires accommodation by the control system.


A free-standing solid composite intumescent structure has at least one bendable metal mesh, preferably at least two, secured on or in a bendable intumescent sheet material. The structure is bendable by a bending force into a shape at a temperature above −10° C. while retaining the bended shape when the bending force is removed. The intumescent sheet material has 10 wt % or more, based on total weight of the sheet material, of a polymeric resin; inorganic filler; and, an intumescent component. Fire protection barriers can be made from the free-standing solid composite intumescent structure, which can be used in fire protection systems where the fire protection barrier is installed on a substrate, for example steel building elements.

Fire proofing is a passive fire protection measure that refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fire proofing system to certain structures allows them to have a fire-resistance rating. In case of a fire, the fire proofing materials must keep their integrity for the purpose of protection.
An important part of modern building design is the protection of structural steel such as columns, beams, girders and other steel assemblies from the damaging effects of fire. Steel does not burn, but can lose strength at high temperatures. As a result, a variety of fire protection systems, namely mineral insulants, cementitious sprays and intumescent coatings, have been developed to insulate steel from the effects of fire in order to prolong the time required for steel to reach a temperature of about 538° C., generally by one to two hours, depending upon local fire regulations.
Intumescent materials, commonly intumescent coatings, are used for fire proofing structural steels. A major advantage of coating is the ability to cover somewhat sophisticated substrates with relative ease. Intumescent coatings are coatings that react under the influence of heat and swell to 10-100 times their original thickness, producing an insulating char that protects the substrate to which the coating is applied from the effects of fire. Because intumescent coatings are needed at a relatively low thickness, as compared with the thickness required for other types of insulating materials to achieve a similar fire protection rating, they are increasingly becoming the preferred choice for structural fire protection. Another attractive feature of intumescent coatings is their smooth and aesthetically pleasing finish. Thin film intumescent coatings therefore allow architects and designers to maximize the creative design possibilities of structural steel.
Typical intumescent coatings usually comprise a minimum of four components: a source of mineral acid catalyst, typically ammonium polyphosphate; a source of carbon, typically pentaerythritol or dipentaerythritol; a blowing agent, typically melamine; and a binder, typically a thermoplastic resin. When an intumescent coating is subjected to heat, a series of reactions occur. The ammonium polyphosphate decomposes to produce polyphosphoric acid, catalyzing the dehydration of pentaerythritol to produce char. The blowing agent also starts to decompose, giving off non-flammable gases that cause the carbon char to foam, thus producing a meringue-like structure that is highly effective in insulating the substrate from heat. The basic function of the binder is to bind together the components of the intumescent coating, so that they may be applied to the substrate and held in intimate contact therewith until required to perform their function in a fire situation. Furthermore, the binder contributes to the formation of a uniform cellular foam structure, since the molten binder helps trap the gases given off by the decomposing blowing agents, thus ensuring a controlled expansion of the char. Binder content must be controlled at certain level. Insufficient binder will result in coating defects such as cracking or delamination, whereas too much organic binder will weaken the char strength and cause higher flame spread rate.
Intumescent coatings are generally categorized into three types: water-based (W/B), solvent-based (S/B), and epoxy-based (E/B). Water-based and solvent-based intumescent coatings are among the most widely used products (over 80% usage in the North American market). These coatings utilize a thermoplastic binder, such as polyvinyl chloride (PVC), polyurethane, polyester, polyvinyl acetate, phenolic resin, acrylic resin, and copolymers of ethylene vinyl acetate, or styrene acrylics. The thermoplastic characteristics of the binder allow the coating to swell significantly (with blowing agent) and form chars 10-100 times the original coating thickness. Therefore, only a relatively thin film is required with water-based or solvent-based coatings. However, significant drawbacks of these types of coatings exist in application and handling
In application, depending on the coating thickness required for fire proofing, a steel member may require 2 to 10 layer of coats. Since only a limited thickness (usually 40-50 mils or 1.0-1 2 mm per day) can be sprayed in a single application without sagging or peeling, and the coating must be allowed to dry (greatly affected by environmental conditions, such as humidity and temperature) before a second layer can be applied, a project may take up weeks or months to finish. Additionally, a trained applicator must apply the coating to ensure that a uniform thickness is applied. For solvent-based systems, the applicator must be aware of special safety considerations, for example inhalation hazards and flammability. Finally, sprayed on coatings are messy and necessitate extensive cleanup of the job site following installation.
In shipping and handling, water-based intumescent coatings quality deteriorates when subjected to freezing or hot temperatures (above 35° C.) conditions. Due to the instability of certain ingredient in water, water-based intumescent coatings usually have shelf lives of about 6 months.
Epoxy-based coatings (e.g. PPG's Pitt-Char® and Akzo Nobel's Chartek® systems) have great durability and are mostly used for outdoor applications, such as offshore platforms or industrial plants. Because of the thermosetting nature of epoxy resins, epoxy-based coatings swell poorly upon heating (only a few times their original thickness) and consequently require greater amounts to be applied in order to attain the desired fire protection rating. The cost of epoxy systems is usually much higher than water-based and solvent-based systems, meaning that the overall project cost is prohibitive for interior applications. In addition, the aesthetic finish is compromised due to the much greater coating thickness required.
Coatings are often reinforced using, for example, short length pieces of glass fibers or mineral fibers mixed with the coating during application. The random direction of the fibers mixed throughout the coating lends reinforcement, reducing the likelihood of sagging, and allowing greater overall coating thickness to be applied to increase fire protection ratings beyond what can be achieved without reinforcement. These fibers are also well known to enhance char strength during fire. However, incorporating long fibrous materials in intumescent coating is prohibitive due to spraying difficulties and aesthetic concerns.
100% solid intumescent fire proofing materials are described extensively in the literature. US 2008/02241005 A1 describes a liquid curable intumescent system by radical polymerization. US 2012/0174508 A1 describes curable intumescent system using a silane-terminated polyurethane or a silane terminated polyether as binder. U.S. Pat. No. 7,217,753 B2 describes a powder coating system using phenolic resin capable of protecting steel substrate for 2 hours. All these systems are thermosetting, potentially requiring sophisticated installation equipment.
Ammonium polyphosphate, melamine, and polyalcohol are well described in literature as non-halogenated fire retarding compound for thermoplastic materials. U.S. Pat. No. 6,043,304 describes a flame-retarded hot-melt adhesive composition, which may be applicable to dimensionally heat-recoverable articles to flow and seal when the articles are heat-recovered in use. U.S. Pat. No. 6,809,129 B2 describes a moldable elastomeric intumescent material comprising chlorinated polyethylene, plasticizer, phosphate based foaming agents, char forming materials, antioxidants, intumescent materials, flame retardant materials, and graphite and/or expandable graphite. JP 2002/322374 describes a moldable intumescent sheet composition for fire protection, which is typically flexible or non-rigid, having an organic binder content typically above 30 wt % of total dry composition and an expansion ratio of up to about 10.
Commonly owned co-pending United States Patent application 61/903,130 filed Nov. 12, 2013 by Tong et al. describes hot melt intumescent materials (HMI) with preferably <20 wt % resin, typically less than 17 wt %, bendable at elevated temperature (90° C.). It also demonstrates that HMI can be reinforced by single layer of metal mesh. U.S. Pat. No. 4,292,358 by Fryer et al. described an intumescent barrier made by applying intumescent coatings over a support medium such as metal mesh. U.S. Pat. No. 4,493,945 described a mesh supported active thermal protective system, in which bending was only possible by scoring the materials at edges. The open edges were then refilled with active thermal protective materials. U.S. Pat. No. 5,404,687 by Blake et al. described an unbendable fire proofing panel where screws must be used to secure structure edges where panels were jointed. WO 02/070622 by Feldman et al. described a flexible thermal protective system using flexible intumescent epoxy coating and embedded mesh.
There remains a need in the art for improved intumescent materials for fire proofing, which may overcome one or more of the problems associated with current fire resistant materials, for example: time associated with the application of the required thickness of conventional coatings; extended drying time associated with conventional coatings (mostly W/B and S/B); limited installation conditions; damaged coating difficult to repair; short shelf life for water-based coating; necessity for jobsite installation; large thickness associated with E/B; expensive equipment required for installation; and extensive cleaning of job site.

Solid composite intumescent structures for fire protection


The invention relates to water soluble or water dispersible powders, tablets, or precursors therefor based on a carbohydrate matrix with improved dissolution properties in water. These components are subjected to treatment with a gas so that gas is entrapped therein, and sufficient closed porosity is provided so that gas entrapped therein promotes dissolution or dispersion upon contact with water. The powders or tablets may be pharmaceuticals or foods that optionally contain an active ingredient therein.

Water soluble powders and tablets based on amorphous carbohydrate matrices are used in many fields. For example, such powders or tablets in a form suitable for human consumption are used in the food, beverage, nutrition, confectionery and pharmaceutical fields. Alternatively the powders or tablets may contain materials such as detergents intended to be dissolved or dispersed in water before use. In many cases, it is desirable that the powders or tablets should dissolve or disperse rapidly on contact with water and, for example, poor tablet dissolution is known to account for many drug-bioavailability problems. The powder or tablet may contain a chemical dissolution aid and such aids are generally combinations of chemicals which are stable in solid form but which generate a gas on contact with water, for example the combination of an acid and a carbonate or bicarbonate. In some cases, the amount of the gas-generating chemicals added is such as to provide effervescent powders or tablets.
One particular type of water soluble carbohydrate powder is soluble foamer and creamer powders which upon addition of a liquid are able to provide a creamy foam and such powders have many uses. For example, they may be used to provide milk shakes or cappuccino style beverages or they may have food applications such as in desserts, soups and sauces. Soluble coffee beverage products which produce cappuccino-type beverages are particularly well known and these are usually a dry mix of a soluble coffee powder and a soluble beverage creamer. Products of this type are known which contain pockets of gas which upon dissolution of the powder produce a foam so that on the addition of water or milk (which will usually be hot), a whitened coffee beverage is produced having foam on the surface which resembles, to some extent at least, traditional Italian cappuccino. Examples of gassed soluble beverage creamers are described in EP-A-0 154 192, EP-A-0 450 310 and EP-A-0 885 566. Soluble beverage creamers which contain chemical foaming agents are also known. The formation of a foam is dependent on the powder containing an ingredient, generally a protein such as casein, which is capable of stabilizing the foam.
In many fields, the presence of gas-generating chemicals is undesirable, for example because of their effect on flavor, or they may even be prohibited. There is a need to provide water soluble or water dispersible carbohydrate based powders and tablets with improved reconstitution properties in water without the need to use such chemical dissolution aids.


A digital distributed antenna system (“DAS”) configured to route at least one reference signal received by at least one digital master unit to at least one digital remote unit. The DAS has at least one processing unit configured to cause the DAS to measure a strength of a received reference signal, determine a required strength that the received reference signal should have upon being transmitted to a wireless communication device located in a coverage area served by the at least one digital remote unit, and adjust a gain of a routing path of the DAS via which the received reference signal is to be routed to an antenna port of the at least one digital remote unit such that the strength of the received reference signal attains the required strength when being transmitted from said at least one digital remote unit.

A distributed antenna system (DAS) is a technology for providing radio coverage in an area which cannot be directly served from the general mobile radio network (for example, tunnels in a metro system, or a building complex), and is particularly advantageous in applications where multiple wireless service providers need to provide coverage since a single DAS can be used with many radio base stations.
A typical digital DAS is shown in FIG. 1 and consists of head-end equipment, herein referred to as digital master units (DMUs) 14, 15, which receive downlink signals from a number of radio base stations (RBSs) 10-13, and convert them for transport on optical fibers 16, 17 via one or more routing units (RUs) 18 to a number of remote nodes 19, 20, herein referred to as digital remote units (DRUs), located in the coverage area which convert the optical signals into radio signals which can be broadcast on antennas driven by the DRUs 19, 20 for transport to/from wireless communication devices (WCDs) 21, 22 such as smart phones and tablets. Each DRU 19, 20 receives uplink signals from its connected antenna(s) and converts them for transmission over the optical fibers 16, 17 back to the DMUs 14, 15 and onward to the RBSs 10-13.
A modern active DAS, as that illustrated in FIG. 1, transports the radio signals in the form of digital samples, usually over fiber optic connections though not always. Digital data transport allows for flexible routing and distribution of radio signals with a much finer degree of control over which signals go to which DRU.
Base station signals are converted into filtered streams of digital data corresponding to the different carrier frequency allocations, and uplink signals are likewise filtered according to the frequency allocations and sent back to the base stations. The base station interface can be analogue (for instance, with radio frequency (RF) downlink and uplink signals) or digital (where the downlink and uplink signals are encoded in digital form).
When the DAS is correctly configured, it appears as a transparent "pipe" through which the signals are transferred in the downlink and uplink directions with an appropriate gain in each direction set by the system installer.
A significant part of the cost of a DAS installation comes from the number of man-hours required to set up and commission the DAS. For a digital DAS, the main tasks are to define the carrier frequency ranges used by the base stations (so that digital filter center frequencies and bandwidths of the DAS are set appropriately) and to set the correct gain parameters so that the required signal level is achieved in each of the coverage areas. In the event of frequency re-farming by the mobile network operator, where the allocation of frequency ranges to particular technologies is changed—for example when replacing a legacy Global System for Mobile Communications (GSM) system with a Long Term Evolution (LTE) system—this manual work needs to be repeated and further; during this time the DAS will likely not provide any radio coverage.
US 2013/071112 discloses a configuration sub-system for telecommunication systems. The configuration sub-system can include a test signal generator, a power measurement device, at least one additional power measurement device, and a controller. The test signal generator can be integrated into components of a telecommunication system. The test signal generator can provide a test signal to a signal path of the telecommunication system. The power measurement device and the additional power measurement device can respectively be integrated into different components of the telecommunication system. The power measurement device and the additional power measurement device can respectively measure the power of the test signal at different measurement points in the signal path. The controller can normalize signals transmitted via the telecommunication system by adjusting a path gain for the signal path based on measurements from the power measurement device and the additional power measurement device.
WO 97/29608 discloses a method and apparatus for integrating a personal communication system with a cable television plant. A set of radio antenna devices (RAD) are connected to the cable plant. The RADs provide frequency conversion and power control of signal received from the cable plant for wireless transmission to the remote units. The RADs also provide power control and frequency conversion of wireless signals received from the remote units for transmission by the RADs onto the cable plant. In addition to the functions of standard base stations and centralized controller, the CATV base station must also compensate for gain variations in the cable plant. The downstream power control is regulated by a RAD reference signal which can be hidden within the CDMA signal for maximum efficiency.

Automatic configuration of a digital DAS for signal dominance


A reflective color pixel includes a first sub-pixel and a second sub-pixel. The first sub-pixel is for generating a first color. A color conversion layer extends through the first sub-pixel and the second sub-pixel and is disposed in a waveguide. The color conversion layer contains a luminescent material, which converts a portion of light incident on the second sub-pixel into light of the first color. The waveguide guides the light of the first color generated by the luminescent material to the first sub-pixel for emission from the first sub-pixel.

Reflective electronic displays are a new type of display device that is gaining popularity. For instance, reflective displays have been used in electronic book readers. In contrast to conventional flat-panel displays, such as LCD displays, that require their own light sources, reflective displays utilize ambient light for illumination to display images that can mimic the look of "ink-on-paper" printed materials. Due to the use of ambient light for illumination, reflective displays have the significant advantages of lower power consumption compared to conventional displays, and the ability to be viewed under bright ambient light. Most of the reflective displays currently commercially available are monochromatic displays, and it is desirable to have reflective displays that can produce color images with satisfactory color brightness.

Hewlett-Packard Development Company, L.P.


A high impact polymer comprising repeating monomer units of the formula: ##STR1## wherein R.sub.2 and R.sub.2 are substituents selected from the group consisting of hydrogen, an alkyl group, an aryl ring and a group promoting hydrogen bonding with a hydrogen atom of a phenyl ring, at least one of R.sub.1 and R.sub.2 being from the group promoting hydrogen bonding.

The invention relates to the field of impact resistant polymers, particularly polymers based on bisphenol-A-polycarbonate.
Impact resistant polymers have found a wide variety of uses as glass substitutes in both military and non-military applications. Such polymers have been used as windshields and windscreens on vehicles, canopies and windows on aircraft, face protection devices, optical storage disks, housings for appliances and business machines and ophthalmic frames and lenses. Due to the weight advantages of these polymers relative to glass, the polymers may also find use as windows for buildings.
Among the transparent polymers which have been used are polycarbonates and acrylics. While polycarbonates have greater impact strength than acrylics, they are not typically used because of limited wearability; the scratch and chemical resistance of these materials has been poor. However, an improvement in impact resistance could lead to an improvement in cost-benefit analysis and life cycle cost and make these materials cost effective competitors to acrylics.
The chemical, physical and mechanical properties which lead to desirable impact resistance for polycarbonates have not been well understood. Polycarbonates dissipate energy upon impact by way of a yielding mode of failure which offers better protection from high energy projectiles than materials which craze and/or crack. This ductile mode of failure upon impact usually results in a punched out plug or closed hole rather than spallation; this provides better ballistic protection and better residual optics.
Numerous theories have been proposed for this ductile mode of failure as opposed to the brittle failure characteristics of many other transparent polymers but no conclusive evidence, nor any hypothesis which accounts for all of the experimental data has been offered to date, and significant improvement in ballistic protection performance in transparent polymers has not been achieved.
The molecular level structure of polycarbonate has been studied by a wide variety of experimental and computational techniques in an attempt to link the mechanical behavior to chain motions occurring at the atomistic level. Single chains of glassy polycarbonate were found to show random coil behavior through light scattering, small angle X-ray scattering and small angle neutron scattering experiments. Wide angle light scattering experiments showed a single phase behavior of glassy polycarbonate with no large regions of strong intermolecular orientation correlations, while wide angle X-ray and neutron scattering analyses indicated that there were many small regions of "enhanced order" in the bulk material, consisting of no more than two or three repeat units. These regions are too small to alter the overall random coil behavior of the chain or to show fluctuations in the optical anisotropy of polycarbonate.
Various nuclear magnetic resonance (NMR) techniques have been used to isolate the motions in polycarbonate. The most obvious motions are 180.degree. flips around the C.sub.2 axis of the phenyl groups, rotation about the C.sub.3 axes of the methyl groups and oscillations about the C.sub.2 axes of the phenyl groups accompanied by 15.degree. main chain reorientation. .sup.1 H NMR line width experiments at various applied hydrostatic pressures showed that the ring flips were suppressed by increased pressure while it was proposed that main chain motions enabled the phenyl ring flips to occur by increasing volume.
Computer models of glassy polycarbonate have been subject to hardware and software limitations. A force field specifically for polycarbonate in the amorphous bulk state was developed recently by Hutnik et al., Macromolecules, 24:5956 (1991), based on the conformational characteristics of the fragment molecules diphenyl carbonate and 2,2 diphenyl propane. They performed quasi-static chain dynamics based on previously proposed static microstructures of amorphous polycarbonate and found that there was significant cooperativity between the motions of the phenyl ring, carbonate group and main chain. More significantly, they found that there was a strong influence of chain packing on the energetics of the analyzed motions and that the phenyl ring flips had far reaching effects which were especially manifest on the carbonate conformation in "soft" regions of the structure. However, the authors concluded that their computations results were not consistent with experimental reality.
An attempt has also been made to improve the properties of polycarbonate by blending with polysulfones or polyetherimides, as reported by Coleman, "Mechanical Properties of Polycarbonate, Polysulfone and Polycarbonate-Polyetherimide Blends," Final Report, NATICK/TR-91-025, April 1991. The polysulfones and polyetherimides were found to be immiscible with polycarbonate and there was no evidence that any intermolecular reactions occurred. The polysulfones and polyetherimides were found to be too stable to undergo any chain scission reaction at temperatures which are low enough to prevent the degradation of the polycarbonate.

Impact resistant polymers based on bisphenol-A-polycarbonate


The present invention provides a package wrapping that utilizes a film having a pair of spaced apart perforations defining a perforation zone there between, a carton label having a pair of spaced apart tabs defining a notch that extends across and makes visible a portion of the perforation zone when the label overlays the film, and an adhesive extending across a portion of the perforation zone and one of the spaced apart tabs wherein the carton label is not adhered to the film.

Packaged articles are often provided with a thin film wrapper to protect the packaged article or to preserve its contents. Various systems have been devised to remove the film wrapper without resorting to tools and the like, such as providing a tear tape or tab. Such tape and tabs help the consumer to open the wrapper by pulling on the tab or tape causing the film to rupture and facilitate removal. Examples of packaged articles provided with such tapes and tabs include packaged consumer goods, packaged media such as compact discs and digital video discs, as well as various packaged food and beverages.
While tabs and tape may be suitable for removing film wrapper from certain packaged articles, they are not well suited for the removal of film is tightly wrapped around the package. Such tight wrapping is often associated with shrink wrap films. Thus the consumer often struggles to remove the wrapper and may find it necessary to use an additional instrument, such as a knife, a pair of scissors, or other sharp instrument, to remove all parts of the film wrapper. This is inconvenient not least because the consumer may not have a suitable additional instrument readily at hand. Furthermore, use of such instrument involves the risk of damaging the article.


This invention is a low cost styrene-soluble unsaturated polyester resin made using recycled or virgin polyethylene terephthalate. The PET is first glycolyzed using inexpensive glycols and then reacted with maleic anhydride and dicyclopentadiene, forming polyesters containing cyclopentadiene added by Diels-Alder reaction and/or norbornyl-terminated polyesters.

Polyethylene terephthalate (PET), made by reacting terephthalic acid or dimethyl terephthalate and ethylene glycol, is a versatile thermoplastic polyester used in synthetic fibers, extruded films such as x-ray films, molded engineering components, and blow molded bottles. Worldwide production of PET is above 1,000,000 metric tons a year. With such enormous production, effective use of PET waste is desirable. Waste PET is readily available at costs as low as 35 cents per kilogram while its raw materials terephthalic acid and ethylene glycol cost 90 cents per kilogram and 40 cents per kilogram respectively.
PET waste can be repelletized and converted into extruded or molded articles. Alternatively, PET can be converted into low molecular weight oligomers by glycolysis using inexpensive ethylene glycol or diethylene glycol or expensive propylene glycol. Certain of these glycolysis products can be further reacted with an unsaturated acid or anhydride to make an unsaturated polyester resin which can be further reacted with large proportions of styrene to make a myriad of products. Unfortunately, as described by Vaidya and Nadkaini, in Industrial Engineering Chemical Research 1987, 26, 194-198; unsaturated polyester resins synthesized from ethylene glycol-based glycolyzed PET are incompatible with styrene monomer. However, Vaidya and Nadkaini found that PET waste depolymerized with expensive propylene glycol could be reacted with maleic anhydride and mixed with styrene monomer to produce useful unsaturated polyester resins. These resins were comparable in processability to conventional general purpose resin.
It would be economically advantageous if a process could be identified in which PET, glycolyzed using less costly glycols than propylene glycol, could effectively be used in producing styrenated, unsaturated polyester resins for commercial use. Any unsaturated polyester made using glycolyzed PET should be highly soluble in styrene so that manufacturers can use abundant proportions of styrene as they make articles. Some new approach is needed in order to solve the problem, described by Vaidya and Nadkaini, of the incompatibility with styrene monomer of unsaturated polyesters made using ethylene glycol based glycolyzed PET.

Styrene soluble unsatured polyester resin from polyethylene terephthalate


Machines for writing braille type having two opposing rows of embossing units each with a support holding a punch-forming stamp guidable between an inactive position and a pushed-out embossing position with abutment against a die member disposed opposite the embossing unit. An electromagnet for each unit controls the stamp with a displaceable plunger. The rows of units are arranged for synchronous movement towards and away from each other in a direction substantially at right angles to the path of movement of a sheet for receiving the type. Each opposing support forms coherent die-punch pairs. Each support has a double-armed rocker which with one end abuts an impressing end of the embossing stamp while the other end projects outwards so that on movement of the support towards the path of the sheet, it is guided substantially at right angles towards the end of the plunger of the electromagnet when said plunger is pushed out.

1. Field of the Invention
This invention relates to machines for writing braille type and having a series of embossing units each with a support which holds a punch-forming stamp which can be guided between a drawn-in and a pushed-out embossing position with abutment against a die member disposed opposite the embossing unit, and an electromagnet arranged for each embossing unit so as to control the position of the stamp with a displaceable plunger.
2. Description of the Prior Art
Such a machine is known in which the embossing units are arranged permanently by the side of each other and in which the stamp movement of the electromagnet is transferred by means of a stationarily mounted, pivotable arm with an activating end which abuts the punch-forming stamp. Such a solution is space-consuming for one thing because the control plunger of the electromagnet must perform a relatively long activating movement. Besides, such a machine only provides the possibility for one-sided embossing of the sheet. Furthermore, the known solution provides for positioning of the magnets in series by the side of each other which demands precise and individual adjustment of the blow in order to bring about uniform and satisfactory embossing.
What is needed then is a compact machine for writing braille type in which the operation can be effected with the least possible inspection and maintenance and with printing on both sides of the sheet.


A controller for a system of the type including a variable temperature heat source arranged in heat exchange relation with a fluid circulating circuit, and a variable speed pump disposed in said circuit for varying the flow rate of fluid therethrough in response to variations in the temperature of the fluid. The controller includes a probe for sensing a temperature indicative of the temperature of the fluid in the circuit and for generating a first signal indicative thereof; means for generating a reference signal indicative of a predetermined temperature; means for comparing the first two signals and generating a third signal indicative of the difference therebetween; means responsive to the third signal for generating an analog control signal; means responsive to the analog control signal for varying the pump speed as a function of the control signal for equalizing the first and second signals.

1. Field of the Invention
This invention pertains to flow controllers and more particularly to analog flow controllers for varying the circulation rate of a fluid in heat exchange relation with a variable temperature heat source such as, for example, a solar collector.
2. Statement of the Prior Art
The use of solar collectors in space heating and hot water systems is well known as are control systems for regulating the temperature of the circulated fluid, typically water. The control systems, which usually regulate a pump interposed in the fluid circulating circuit, fall into two main categories: on-off controllers and proportional controllers.
On-off regulators employ a temperature sensor disposed to sense the temperature of the water at some point in the system, typically at the output of the collector. The signal from the sensor is sent to a pump controller which deactivates the pump whenever the sensed temperature drops below a reference temperature and activates the pump whenever the sensed temperature exceeds the reference temperature. The reference temperature may be directly dependent on some system parameter, such as the storage water temperature, or may be a fixed value independent of system parameters. Examples of typical on-off regulators may be found in U.S. Pat. Nos. 3,998,207, 4,062,349, 4,019,495, 4,034,738 and 4,063,545.
Regardless of the reference signal selected, on-off controllers result in excessive strain on the pump motor due to constant activation and deactivation thereof. Perhaps more importantly, on-off controllers cannot accurately regulate the temperature of the water leaving the collector due to the time lags inherent in a system which varies the flow rate of the water between zero and some fixed rate. Accordingly, such systems are accompanied by relatively wide fluctuations in the collector water temperature. In most applications, this results in reduced efficiency of the solar heating system. For example, where the solar heating system is used as a hot water heater, it is desirable to keep the temperature at the output of the collector at or near a predetermined value. If the temperature is below the predetermined value, the temperature gradient between the collector water and the storage water may be too low with the result that no heat will be available from the solar heater. On the other hand, if the temperature gradient between the collector water and the storage water is too high, excessive heat is lost to the atmosphere. In either case, the result is reduced efficiency.
Proportional controllers operate on the principle that the flow rate of the collector water through the system is proportional to the temperature of the collector water or some temperature difference, for example, the temperature difference between the water at the output of the collector and the storage water temperature. The proportionality constant is determined by the particular system parameters. Unlike on-off controllers, the signal from the proportional controller is utilized to vary the pump speed and hence the flow rate of the water circulated through the collector. Because this virtually eliminates system cycling, strain on the pump motor is reduced. However, although they are an improvement, proportional controllers, like on-off controllers, cannot maintain a fixed temperature at the collector output. For example, when the collector temperature drops due to a change in ambient conditions, the proportional controller will reduce the pump speed and hence the flow rate in an effort to raise the collector temperature. However, because proportional controllers operate on a pre-set proportional relationship between flow rate and temperature, the new set point established by the proportional controller corresponds to a different temperature than the original temperature at the higher flow rate. It is thus apparent that the collector water temperature in a system regulated by a proportional controller is partially dependent on ambient conditions. Exemplary proportional controllers are described in Hawthorne Industries, Inc.'s Product Information Bulletins for their Model Nos. H-1511-A and H-1510-B.
It is therefore apparent that prior art controllers for regulating the flow rate of fluid through a solar heating system are incapable of maintaining a fixed, predetermined fluid temperature at the output of the collector.


A multi-piece rim structure for a wheel includes a rim base 10, a bead seat ring 20 (ring member) and a lock ring 30. The bead seat ring 20 receives a load in a radial direction and an axial direction from a bead portion of a tire. An annular ridge 35 of the lock ring 30 can be received in an annular lock ring groove 15 of the rim base 10. A receiving groove 15a is formed in an inner surface of the lock ring groove 15 of the rim base 10. A sacrificial anticorrosion material 80 is embedded in the receiving groove 15a. The sacrificial anticorrosion material 80 includes metal such as zinc and aluminum that has a greater ionization tendency than iron that is a base material of the rim base 10 and the lock ring 30. Corrosion of the rim base 10 and the lock ring 30 can be suppressed by ionization of the sacrificial anticorrosion material 80.

A rim structure of a wheel for an off-road type large vehicle such as those used in mines is typically composed of multiple pieces to make it easy to mount a large-weight tire.
A known multi-piece rim structure 1 shown in FIG. 6 includes five pieces, i.e., a rim base 10, a bead seat ring 20 (ring member), a lock ring 30 and a pair of side rings 40, 50. "Axial direction", "radial direction" and "circumferential direction" used in this specification respectively refer to an axial direction, a radial direction and a circumferential direction of the multi-piece rim structure. "Outside in the axial direction" refers to a side away from a central position of a tire set in the multi-piece rim structure in the axial direction. "Inside in the axial direction" refers to a side closer to the central position of the tire in the axial direction.
The rim base 10 is made by welding three short cylindrical members one by one arranged in the axial direction (width direction). Each of the short cylindrical members is made by rounding a strip of rolled steel plate into a cylindrical shape and welding opposite end surfaces thereof.
The rim base 10 includes a gutter band portion 11 on one side thereof in the axial direction and a back flange portion 12 on the other side thereof.
The bead seat ring 20 is disposed on an outside of the gutter band portion 11 of the rim base 10 in the radial direction. One of the side rings 40 is disposed on an outside of the bead seat ring 20 in the radial direction. The side ring 40 is caught by an annular raised flange portion 21 formed in a peripheral edge of the bead seat ring 20 located outside in the axial direction. The other side ring 50 is caught by the back flange portion 12 of the rim base 10.
An outer peripheral surface of the bead seat ring 20 is provided as a bead seat portion 22 having a width W. An outer peripheral surface of a portion of the rim base 10 adjacent to the side ring 50 is provided as a bead seat portion 13 having a width W. The bead seat portions 22, 13 are arranged to have a pair of bead portions of a tire (not shown) placed thereon. An annular load applying surface 23 having a tapered configuration is formed in an inner periphery of an edge portion of the bead seat ring 20 located outside in the axial direction.
To mount a tire to the multi-piece rim structure 1 described above, the side ring 50, the tire, the side ring 40 and the bead seat ring 20 are moved in this order in the axial direction from the gutter band portion 11 toward the back flange portion 12 to be mounted on the rim base 10, and finally, the lock ring 30 is received in the rim base 10.
Prior to the mounting of the bead seat ring 20, a seal ring 60 that is an O-ring is fitted into a seal ring groove 16 (to be described later) of the gutter band portion 11. The seal ring 60 is provided for sealing between the bead seat ring 20 and the gutter band portion 11.
A multi-piece rim structure 1′ shown in FIG. 7 is also well-known. The multi-piece rim structure 1′ includes three pieces, i.e., a rim base 10′, a ring member 5 and a lock ring 30. The rim base 10′ integrally includes a side ring portion 50′. The side ring portion 50′ corresponds to the side ring 50 and the back flange portion 12 of the multi-piece rim structure 1 shown in FIG. 6. The ring member 5 integrally includes a bead seat ring portion 20′ and a side ring portion 40′. The bead seat ring portion 20′ and the side ring portion 40′ respectively correspond to the bead seat ring 20 and the side ring 40 of the multi-piece rim structure 1 shown in FIG. 6. Other features are similar to those shown in FIG. 6, and therefore, are designated by the same reference numerals and description thereof will be omitted.
Rim structures 1A, 1B used in a dual-wheel type vehicle shown in FIG. 8 are also well-known. The rim structure 1A that holds an inner tire Ta closer to the vehicle has similar features to those in FIG. 6. In the rim structure 1B that holds an outer tire Tb farther from the vehicle, opposite end portions of a rim base 10″ in the axial direction are provided as gutter band portions 11. A bead seat ring 20, a lock ring 30 and a side ring 40 are mounted on each of the gutter band portions 11.
The gutter band portion 11 and the lock ring 30 of the rim structures 1, 1′, 1A, 1B will be described hereinafter particularly referring to FIG. 9. A lock ring groove 15 and a seal ring groove 16 are formed in an outer peripheral surface of the gutter band portion 11. The seal ring groove 16 is disposed inside in the axial direction with respect to the lock ring groove 15. The lock ring groove 15 has a concavely curved cross-sectional contour. A first receiving surface 17 that is a circular cylindrical surface is formed inside in the axial direction with respect to the lock ring groove 15, i.e. between the lock ring groove 15 and the seal ring groove 16. A second receiving surface 18 that is a circular cylindrical surface is formed outside in the axial direction with respect to the lock ring groove 15, i.e. between the lock ring groove 15 and an outer side edge of the gutter band portion 11.
The lock ring 30 is disposed between the gutter band portion 11 of the rim base 10 and the bead seat ring 20 (or the ring member 5). The lock ring 30 has an annular configuration that is cut at one point. A load receiving surface 31 having a tapered annular configuration is formed in an outer periphery of an edge portion of the lock ring 30 located inside in the axial direction.
The lock ring 30 includes an annular ridge 35 at an intermediate position of an inner periphery thereof in the axial direction. The ridge 35 continues in the circumferential direction. The lock ring 30 further includes a first abutment surface 37 that is a circular cylindrical surface located inside in the axial direction with respect to the ridge 35. The lock ring 30 further includes a second abutment surface 38 that is a circular cylindrical surface located outside in the axial direction. The ridge 35 has a convexly curved cross-sectional contour.
In a state where the lock ring 30 is mounted in the gutter band portion 11, the ridge 35 is received in the lock ring groove 15 of the gutter band portion 11. The load receiving surface 31 is surface-contacted with the load applying surface 23 of the bead seat ring 20 (or the ring member 5). The first abutment surface 37 is surface-contacted with the first receiving surface 17 of the gutter band portion 11. The second abutment surface 38 is surface-contacted with the second receiving surface 18.
In the multi-piece rim structures 1, 1′, 1A, 1B having the tire mounted thereon, a load in the radial direction is applied to the bead seat ring 20 (or the bead seat ring portion 20′ of the ring member 5) from one of the bead portions of the tire. Moreover, a load in the axial direction is applied to the bead seat ring 20 (or the bead seat ring portion 20′ of the ring member 5) from the one of the bead portions via the side ring 40 (or the side ring portion 40′). Most of the load in the radial direction and the load in the axial direction applied to the bead seat ring 20 (or the ring member 5) is transmitted to the lock ring 30 via the load applying surface 23 and the load receiving surface 31 and transmitted to the gutter band portion 11 from the lock ring 30.
A load transmission path from the lock ring 30 to the gutter band portion 11 will be described in detail. The load in the radial direction is transmitted via a surface contact region R1 in which the first abutment surface 37 and the first receiving surface 17 are contacted and a surface contact region R2 in which the second abutment surface 38 and the second receiving surface 18 are contacted. The load in the axial direction is transmitted via a surface contact region R3 in which a portion of an outer surface of the ridge 35 of the lock ring 30 located outside in the axial direction and a portion of an inner surface of the lock ring groove 15 located outside in the axial direction are contacted.
In the surface contact regions R1, R2, R3, minute reciprocating sliding may occur between the gutter band portion 11 and the lock ring 30 and repeated load may be applied accompanying the running of the vehicle, which may lead to thinning caused by abrasion. Particularly in the surface contact region R3, it is known that cracks 100 may be generated due to fretting fatigue. If such thinning and cracks are left unattended, parts may come off while running, which may make the vehicle immovable.
Thinning due to corrosion may also occur in the multi-piece rim structures 1, 1′, 1A, 1B mentioned above. Specifically, the ridge 35 of the lock ring 30 is received in the lock ring groove 15 of the gutter band portion 11 with play in the radial direction and the axial direction. Since the lock ring 30 receives load outward in the axial direction from the bead portions of the tire, a gap 70 may be formed between an area from a portion of the outer surface of the ridge 35 located inside in the axial direction to a top portion of the outer surface of the ridge 35 and an area from a portion of the inner surface of the lock ring groove 15 located inside in the axial direction to a bottom portion of the inner surface of the lock ring groove 15. Areas of the outer surface of the ridge 35 and the inner surface of the lock ring groove 15 spacedly opposed to each other with the gap 70 interposed therebetween is indicated by reference numeral R0. It should be noted that the lock ring 30 is temporarily moved inward in the axial direction when the lock ring 30 is removed or attached for exchanging tire or when air pressure of the tire is reduced or when the air pressure is increased, and the gap 70 disappears in the region R0. In this condition, the ridge 35 of the lock ring 30 is surface contacted with the portion of the inner surface of the lock ring groove 15 located inside in the axial direction.
Water may pool in the gap 70 if water enters the lock ring groove 15 from a cut portion of the lock ring 30 or if moisture existing in the gap 70 condensates. Therefore, the regions R0, R1, R2, R3 may be corroding environment, in which corrosion thinning may easily occur in the surface contact regions R1, R3.
Particularly, in the surface contact region R3, the fretting fatigue may be accelerated by corrosion and abrasion because stress concentration is significant in this region. Therefore, growth of the cracks 100 may be accelerated in this region.
To cope with this problem, as disclosed in Patent Document 1 to be described later, the applicant suggests providing fretting resistance and corrosion resistance to the multi-piece rim structure by forming painted film layers of normal temperature drying paint on the inner surface of the lock ring groove of the gutter band portion and the first and second receiving surfaces adjacent to the lock ring groove and forming coated layers of normal temperature drying lubricant on the painted film layers.
As disclosed in Patent Document 2 to be described later, the applicant also suggests forming hardened layers on the inner surface of the lock ring groove of the gutter band portion and the first and second receiving surfaces by ion nitriding treatment.


A method of preparing chlorine dioxide in a non-aqueous liquid is disclosed. An aqueous solution of chlorine dioxide is mixed and agitated with a non-aqueous liquid. The chlorine dioxide is extracted into the non-aqueous liquid. In a preferred embodiment, an aqueous chlorite solution is added to a quantity of non-aqueous liquid. Acid is added to the aqueous phase to generate chlorine dioxide. The phases are vigorously agitated to extract the chlorine dioxide into the non-aqueous phase. High concentrations of very pure chlorine dioxide are obtainable. In another preferred embodiment, chlorine is prepared in a non-aqueous liquid and is mixed and agitated with an aqueous chlorite solution. Separation of the aqueous and non-aqueous phases provides pure solutions of chlorine dioxide in the non-aqueous liquid. Very pure aqueous solutions of chlorine dioxide are prepared by mixing and agitating non-aqueous solutions of chlorine dioxide with water. A reactant useful in oxidation, synthesis, disinfecting and sterilizing comprising chlorine dioxide dissolved in a non-aqueous liquid is disclosed.

Chlorine dioxide is a highly active chemical which has been widely used in a variety of processes and especially in disinfecting, sterilizing and bactericidal applications. Due to the unstable nature of gaseous chlorine dioxide when compressed, it is commonly prepared on site rather than having it placed in a container and shipping the container for usage at a site when and where needed. Liquid chlorine dioxide is considered to be very hazardous and is generally avoided.
The prior art discloses numerous procedures and generators for the preparation of chlorine dioxide. A partial listing of these are as follows:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 2,323,594 Hampel July 5, 1943 2,436,134 Aston February 7, 1948 2,484,402 Day et al October 11, 1948 4,081,520 Swindells March 28, 1978 4,250,144 Rategan February 10, 1981 4,247,531 Hicks January 27, 1981 4,590,057 Hicks May 20, 1986 4,861,514 Hutchings August 29, 1989 ______________________________________
All current commercial processes for generation of chlorine dioxide involve methods for combining sodium chlorate or sodium chlorite with acids or oxidizing agents in aqueous systems. The chlorine dioxide produced is isolated as an aqueous solution with concentrations varying from a few parts per million to over 9,000 parts per million. The process leading to this latter high concentration is an exception, and involves a recirculating loop to add new chlorine dioxide values to solutions already containing freshly generated chlorine dioxide.
U.S. Pat. No. 2,678,922 prepares an aqueous solution of chlorine dioxide and flushes the chlorine dioxide from the solution with air. The chlorine dioxide-air stream is passed through liquid chlorine to provide a liquid chlorine/chlorine dioxide solution. The only other non-aqueous solutions of chlorine dioxide of which I am aware are U.S. Pat. Nos. 3,056,270 and 3,084,995 in which chlorine dioxide gas is dissolved in liquid carbon dioxide. The latter reference states that it has been proposed to prepare chlorine dioxide in carbon tetrachloride but this has not proven to be successful due to the slight solubility of chlorine dioxide and because of spontaneous decomposition.
Furthermore, the use of organic materials with chlorine dioxide is generally avoided. Hampel does report the reaction of aqueous chlorate solutions with aqueous solutions of aldehydes to produce chlorine dioxide. Aston reports the "unexpected" reactions of organic acid anhydrides with aqueous solutions of chlorates to produce chlorine dioxide. The Merck Index, Tenth Edition, 1983 provides several references to the preparation of chlorine dioxide but provides the italicized warning "reacts violently with organic materials."
Thus, despite the interest in chlorine dioxide and the numerous methods of generating chlorine dioxide, the preparation and use of chlorine dioxide in a water-immiscible phase has not been disclosed. In fact, the prior art very strongly teaches away from such a preparation.

Generation of chlorine dioxide in a non-aqueous medium


A semiconductor package includes a semiconductor chip having two or more regions that partially overlap so as to define an overlapping region. Through-holes are defined through the two or more partially overlapping regions. One or more first electrodes are disposed on inner surfaces of the semiconductor chip within the through-holes. One or more second electrodes are disposed so as to be insulated from the first electrodes. The one or more second electrodes are at least partially disposed in the overlapping region. Insulation members are disposed in the through-holes.

The present invention relates generally to semiconductor technology, and more particularly, to a semiconductor package.
Developments in the semiconductor industry including the semiconductor chip and the package in which the chip is formed has made it possible to both store and process a massive amount of data within a short period of time.
Recently, a stacked semiconductor package, in which at least two semiconductor chips are stacked so as to further increase data storage capacity and data processing speed, has been suggested.
In order to realize the stacked semiconductor package, connection members for electrically connecting two semiconductor chips are needed.
In a conventional stacked semiconductor package, semiconductor chips are electrically connected using mainly conductive wires. However, when stacked semiconductor chips are electrically connected using the conductive wires, the lengths of the conductive wires for connecting the chips will vary depending upon the respective positions of the stacked semiconductor chips, which in turn complicates high speed operation of the stacked semiconductor package.


There are described herein methods and systems for estimating a system parameter in a closed loop scheme using a sensor model associated with a sensor performing a measurement of the system parameter. Past and current measurements of the parameter are used to provide an initial estimate of the system parameter and sensor dynamics are used to refine the estimated parameter.

Many sensors cannot measure rapid changes in a given parameter, such as temperature or pressure, as they exhibit time delays. This is problematic in engine control systems when data from the sensor is used to make engine decisions. For example, in a gas turbine engine, temperature sensors are located at the exhaust duct. At this location, shielding is required that will slow down the time response of the temperature sensor.
Electronic engine control systems sometimes compensate the slow dynamics of the temperature sensor by introducing lead or derivative type compensation in inter turbine temperature limiting loops. However, this type of controller has to be designed on a case-by-case basis and its tuning is very time-consuming. Other compensation methods are also known, but they are susceptible to noise, require additional components, and in some cases involve linking the measured parameter to a specific engine dynamic, which is not always feasible.
There is therefore a need to improve on techniques used to correct measurement signals from sensors.

Estimating system parameters from sensor measurements


Waveform estimating section 302 observes the amplitude and phase of pilot signals outputted from pilot despreading section 301, and estimates the amplitude, frequency and phase of the pilot signals having no interference. Sine wave generating section 303 generates pilot signals of sine wave of the estimated amplitude, frequency and phase. Coherent detecting section 305 corrects the phase shift of data signals outputted from data channel despreading section 304, using the generated pilot signals.

1. Field of the Invention
The present invention relates to a CDMA system wireless communication apparatus and wireless communication method, in which demodulation is carried out by a pilot coherent detection.
2. Related Art
Recently, in the Cellular system such as automobile telephones and portable telephones, etc., an effective utilization technique of frequencies which is capable of securing a capacity of a number of subscribers on limited frequency bands has become important.
A code division multiple access (CDMA) system has been noted as one of multiple access systems which is able to effectively utilize frequencies. The CDMA system is also called "Spread Spectrum Multiple Access (SSMA) system", which is able to achieve excellent communication quality by a wide band feature and a correlational property by codes of pseudorandom noise (PN), etc.
A land mobile communication system in which the CDMA system is employed, is disclosed in, for example, U.S. Pat. No. 4,901,307. As one of the CDMA systems, there is a direct spread system in which pseudorandom noise codes (hereinafter called "spread code") are multiplied onto transmission signals.
In a case where the direct spread system is employed, it is possible to increase a diversity effect by receiving in rake and synthesizing the multi-path components in the maximum ratio. Rake receiving is disclosed in, for example, U.S. Pat. No. 5,109,390.
Hereinafter, a description is given of the outline of CDMA wireless communication system in which the direct spread system is employed, with reference to FIG. 1. FIG. 1 is a block diagram showing the configuration of CDMA wireless communication system using the direct spread system.
As shown in FIG. 1, the transmission side of CDMA wireless communication system is mainly composed of a data modulating section 1 for modulating the transmission data, a spread code generating section 2 for generating spread codes, a spread modulating section 3 for multiplying spread codes onto transmission signals, and a transmission antenna 4 for wirelessly transmitting transmission signals.
Furthermore, the receiving side of the same system is mainly composed of a receiving antenna 5 for receiving signals wirelessly transmitted from the transmission side, a synchronous acquisition section 6 for generating spread codes at the same timing as that of those generated by the spread code generating section 2, a despreading section 7 for multiplying spread codes onto receiving signals, and a data demodulating section 8 for demodulating despread receiving signals.
In a CDMA wireless communication system constructed as described above, transmission data such as voice data is modulated by the data modulating section 1, and the modulated signals are narrow-band signals having only a band width necessary for transmission as shown at (a).
Furthermore, the band width of spread codes generated by the spread code generating section 2 is sufficiently wide in comparison with the band width of signals modulated by the data modulating section 1 as shown at (b).
The signals modulated by the data modulating section 1 are transmitted by the transmission antenna 4 with the spread codes thereof multiplied by the spread modulating section 3.
Signals received by the receiving antenna 5 are multiplied again by the despreading section 7 with spread codes generated by the synchronous acquisition section 6 and are despread from a wide band to a narrow band.
Interference resulting from other users and thermal noise, etc. are caused to add on the transmitted signals in the process to the receiving side as shown at (c). However, since spread codes have sufficiently small correlation with the interference, the interference are reduced by the despreading section 7 as shown at (d) to cause the received data to be detected.
Here, in the CDMA wireless communication system such as a down link of Cellular system, etc., there is such a type where pilot signals which are already known to each user are always or periodically transmitted through a pilot channel using the pilot channel along with a data channel for transmitting data with respect to the users.
At the receiving side of the CDMA wireless communication system, using signals (hereinafter called "pilot signals") transmitted through the pilot channel, several processes such as synchronous acquisition, tracking, estimation of multi-path condition, coherent detection, frequency synchronization, hand-off, etc. are carried out. Of them, coherent detection process of signals (hereinafter called "data signals") transmitted from the data channel using the pilot signals is called "pilot coherent detection".
Hereinafter, a description is given of the pilot coherent detection in a conventional wireless communication apparatus, with reference to a block diagram shown in FIG. 2. Furthermore, FIG. 2 corresponds to the synchronous acquisition section 6 and the despreading section 7 of FIG. 1.
As shown in FIG. 2, the conventional wireless communication apparatus despreads receiving signals using pilot spread codes, and the apparatus is mainly composed of a pilot despreading section 11 for detecting pilot signals, an averaging section 12 for averaging the detected pilot signals as described later, a data despreading section 13 for despreading the received signals using spread codes for data and for detecting the data signals, and a coherent detecting section 14 for correcting the phase shift of data signals using the averaged pilot signals.
With regard to signals received by the wireless communication apparatus constructed as described above, pilot signals are detected by being despread with spread codes for pilot at the pilot despreading section 11 and data signals are detected by being despread with spread codes for data at the data despreading section 13.
The detected pilot signals are averaged by the averaging section 12, wherein the phase shift of the data signals is corrected by the coherent detecting section 14 on the basis of the averaged pilot signals.
Next, a description is given of the averaging of pilot signals, wherein it is assumed that the spread is carried out by quadrature phase shift keying system (QPSK system).
Pilot signals outputted from the pilot despreading section 11 are expressed by formula 1 shown below; EQU I.sub.0 (t)=A.sub.0.multidot.cos .phi.(t)+n.sub.0.sup.I (t) EQU Q.sub.0 (t)=A.sub.0.multidot.sin .phi.(t)+n.sub.0.sup.Q (t) Formula 1
where A.sub.0 shows the level of pilot signals, .phi.(t) shows a carrier phase offset, and n.sub.0.sup.I (t), n.sub.0.sup.Q (t) show interference. The interference includes interference of other multi-path waves, interference of channels other than the pilot channel, and interference of other cells., etc.
Pilot signals are averaged by the averaging section 12 in the period of time for which the values of cos .phi.(t), sin .phi.(t), etc. are regarded to be constant. By this averaging, the interference are decreased, the level A.sub.0, and values of cos .phi.(t) and sin .phi.(t) of the pilot signals are obtained. Furthermore, the data signals outputted from the data despreading section 13 for user k are expressed by formula 2 described below; EQU I.sub.k (t)=A.sub.k.multidot.d.sub.k (t).multidot.cos .phi.(t)+n.sub.k.sup.I (t) EQU Q.sub.k (t)=A.sub.k.multidot.d.sub.k (t).multidot.sin .phi.(t)+n.sub.k.sup.Q (t) Formula 2
A.sub.k indicates the level of spread code of user k, d.sub.k (t) indicates the data of user k, and n.sub.k.sup.I (t), n.sub.k.sup.Q (t) indicates interference.
If it is assumed that there is no interference in the pilot signals and data signals after averaging, that is, if it is assumed that interference n.sub.0.sup.I (t), n.sub.0.sup.Q (t), n.sub.k.sup.I (t), n.sub.k.sup.Q (t) in formulas 1 and 2 are zero (0), the carrier phase offset is corrected by an inner product calculation at the coherent detecting section 14, wherein demodulation signals expressed by the following formula 3 can be obtained. EQU I.sub.0 (t).multidot.I.sub.k (t)+Q.sub.0 (t).multidot.Q.sub.k (t)=A.sub.0.multidot.A.sub.k.multidot.d.sub.k (t) Formula 3
Herein, in wireless lines such as mobile communications, the level A.sub.0 of pilot signals and phase offset .phi.(t) change in line with movement of a mobile station, a frequency shift occurs due to fading in addition to carrier frequency offset of a local oscillator at the receiving side.
However, the abovementioned conventional wireless communication apparatus is not able to correct the phase shift of date signals unless the cycle of averaging is in the period of time for which the value of cos .phi.(t) and sin .phi.(t) of formula 1 can be regard to be constant.
Since the cycle of averaging needs much shorter than the carrier frequency offset or the frequency shift due to fading, the abovementioned conventional wireless communication apparatus is not able to sufficiently decrease the interference added onto the received signals in a case where the carrier frequency offset or the frequency shift occurs due to fading. As result, the demodulation signals are deteriorated after pilot coherent detection is performed, and the receiving quality is lowered.

Wireless communication apparatus and wireless communication method

Matsushita Electric Industrial Co., Ltd.


An analog-to-digital converter (ADC) having two cascaded A/D stages of the parallel type wherein the analog signal is compared with a set of threshold reference voltages. The first stage develops a set of most-significant bits and produces two analog residue signals: a normal residue corresponding to the difference between the analog input and the threshold voltage below the analog input, and a second residue corresponding to the difference between the analog input and the threshold voltage above the analog signal level. These two residue signals are amplified and directed to the second A/D stage. The sum of the residue signals equals one LSB of the first A/D stage, so that the two residues supply to the second stage information about the quantization error of the previous stage as well as the quantization step size to be used to define full-scale at the second stage. The second A/D stage includes a parallel converter for developing a set of less-significant bits representing the ratio of the normal residue signal to the sum of the two residue signals. The most-significant and less-significant sets of bits are combined to provide the final digital output. Errors due to inaccuracies in interstage gain are reduced due to the use of two residue signals for generating the less-significant bits.

1. Field of the Invention
This invention relates to analog-to-digital converters. More particularly, this invention relates to cascaded multi-stage converters wherein each stage develops a corresponding part of the final digital output signal. The embodiments described hereinbelow utilize converter stages of the parallel type.
2. Brief Description of the Prior Art
Parallel or "flash" converters of various designs have been available for some time, and have speed of conversion as their principal goal. Conventional designs of this type for developing high-resolution outputs, such as 8 or 10 bits, have the disadvantage of requiring considerable circuitry, especially including a large number of comparators with associated logic. One approach to reducing the number of comparators is shown in U.S. Pat. No. 4,270,118 (Brokaw).
Still another design approach is to employ a successive series of stages (or cycles of operation) each arranged to develop a digital output of limited scope, e.g. 3 bits, and to produce from each stage (or cycle of operation) an analog residue signal as the input for the next stage (or cycle). In this way, a high-resolution output can be developed by combining the digital outputs of the several stages or cycles, which are sometimes referred to as sub-ranging stages or cycles. An example of this kind of converter is shown in U.S. Pat. No. 4,814,767 (Fernandes et al).
A major limitation of multi-stage ADC architectures results from the need for interstage amplification, particularly when the overall resolution exceeds about 9 bits. Such amplification is for the purpose of raising the residue of one conversion to a level which can be digitized by the next subsequent stage. In present designs, the gain of such amplification must be quite precisely controlled, in order to produce an accurate digital output.
The need for accurate amplification can be understood from consideration of the diagram of FIG. 1. This diagram shows a prior art multi-stage ADC having a first A/D stage 20, a DAC 22, and a summation circuit 24 to produce a residue signal. This residue signal is amplified by an interstage gain block 26 driving a second A/D stage 28. The digital outputs of the two A/D stages are combined to develop the final digital output.
In the system of FIG. 1, the size of one step of the DAC 22, when multiplied by the interstage gain, must exactly match the full-scale range of the second A/D stage. For example, if the complete converter is a 10-bit ADC comprised of a 5-bit DAC and two 5-bit A/D stages, and if the A/D stages have a 2-volt full-scale range, the residue into the interstage gain block 26 will be .+-.0.5 LSB at the 5-bit level, or .+-.1V/32 =31.25 mV. This must be amplified to provide .+-.1 volt full-scale, so a gain of 32 is required. This will provide from the second A/D stage 32 full codes between every threshold of the first stage. If, for example, the gain were only half of that required, there would be only 16 codes available at the second stage, so the converter performance would suffer significantly.
Various techniques have been devised to minimize problems from interstage gain inaccuracies. For example, the prior art has used so-called reference refreshing, error averaging, and self-calibration. Efforts also have been directed to improving gain accuracy, as by laser trimming of amplifier components. However, these techniques have not satisfactorily solved the problem.


Protective and residual organic coatings are stripped from a surface by substantially sealing the surface from the atmosphere to provide a stripping zone, forming a stream of gaseous stripping composition in an evaporation zone, contacting the surface with the stripping composition in the gaseous state at about ambient temperature and recirculating the gaseous mixture from the stripping zone to the evaporating zone and back to the stripping zone to rapidly increase the concentration of gaseous stripping composition in the stripping zone. Optionally the surface may be rinsed by raising the temperature of the gaseous stripping composition slightly above ambient temperature, whereby the gaseous stripping composition condenses on the surface and flushes the surface free of adhering particles. This process is useful for objects which can be placed in a stripping zone and substantially sealed from the atmosphere, especially objects having an irregular surface, and also for interior surfaces which can be substantially sealed from the atmosphere, including extensive surfaces such as those of storage tanks, tank cars and the holds and ballast tanks of ships.

The present invention relates to a method for stripping organic coatings from coated objects. More particularly, the present invention concerns a method for stripping protective coatings obtained from compositions based on organic resins and/or prepared with organic vehicles, such as paint, shellac, varnish, lacquer and the like, as well as residual coatings, including oils, asphalts, tars and synthetic polymers such as polystyrene. The method of the invention is especially useful for removing such coatings from objects having irregular surfaces and from large surfaces, including vertical and inclined surfaces in the interior of large constructions, such as storage bins and tanks on land and holds and ballast tanks of ships.
Commonly, paint is stripped from paint objects on a small scale by application of an organic or inorganic solvent or mixture thereof, as discussed in Kirk-Othmer's ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY, Vol. 14, pp. 485-493, 2nd Edition, John Wiley and Sons, 1967.
Among solvents which many formulations employ, hydrocarbons, halocarbons, and particularly methylene chloride (dichloromethane) have been found to be particularly effective. Liquid stripping compositions usually contain additives including thickeners, evaporation retarders and detergents.
Organic solvent formulations for stripping paint and other coatings may be of the "scrape off" type or "flush off" type. Generally, the stripping composition is applied to the coated object by one of the foregoing methods and allowed to stand for some time, after which, the coating which has become swollen and/or softened is removed from the surface, by scraping, in the case of "scrape off" formulations or by flushing with water and/or by wiping with a damp rag in the case of "flush off" formulations.
The foregoing methods are expensive, since the organic solvent, except in the case of application by immersion, is not recovered. Moreover, all of the known procedures are generally dangerous and prohibitively expensive where large surfaces are involved. In addition, the waxes used as evaporation retarders in such formulations are difficult to remove completely and any residual wax interferes with the adhesion of subsequent coatings to the surfaces.
Processes have also been described in U.S. Pat. Nos. 2,689,198 to Judd; 3,794,524 to Nogueira et al and 3,832,235 to Cooper et al, wherein paint is stripped from a relatively small object by contact with the vapors from a boiling solvent composition. In these processes the hot vapors condense to liquids on the painted surface.
A method for cleaning tanks has been disclosed in U.S. Pat. No. 3,042,553 to Kearney et al wherein a solvent is heated to the boiling point to produce solvent vapors which are fed to a tank where they condense and wash the tank walls.
Such methods are not applicable for removing organic coatings from extensive surfaces because the cost of heating a sufficient amount of solvent to reflux for an extended period is prohibitive and moreover, expensive solvent-proof equipment is needed to carry out such an operation on a large scale. Furthermore, in some constructions, such as large metal tanks and ships, a temperature differential from one part of the construction to another can be harmful.
Systems wherein a liquid solvent mist is sprayed on a workpiece have also been used to clean surfaces, as disclosed for example in U.S. Pat. Nos. 4,101,340 to Rand and 2,756,168 to Ruggles. Spray washing requires a large amount of energy and therefore is undesirable in view of the expense and the increasing need to conserve energy.
It is the current industrial practice to remove paint and most other protective coatings from large tanks and other large constructions by the slow, unpleasant, expensive and dangerous procedure of abrasive blasting. It is important that a ballast tank of a ship, which usually carries ballast water, be rust-proof. To this end, ballast tanks are coated with a layer of paint. If the paint coating blisters or fails in any way, it is necessary to remove the paint from the interior of the ballast tank and repaint, to avoid the possibility of rust and eventual holes. This is especially important for ships which carry liquified natural gas. A ballast tank of a ship may have a capacity as large as one million gallons or more and often has a complex "honeycomb" configuration which makes it difficult and laborious for a blaster to work through. Removal and disposal of the large amount of blasting grit needed are costly.
To date, even though abrasive-blasting has severe disadvantages, it is practically the only procedure in use for removing paint from large surfaces; hydroblasting and even pounding with hammers are sometimes employed.
There is a tremendous demand for more effective and less labor-intensive methods for cleaning fixed storage tanks as well as tank cars of railroads and trucks, barge and ship holds of petroleum residues such as tar, pitch, asphalt, and oil, vegetable oil residues and residues of synthetic polymers such as polystyrene which result from storage of the monomer, preparatory to a change in type of cargo, structural repairs, or inspection by government agencies. Some of these tanks and holds have a capacity of more than 20,000,000 gallons.
At present they are cleaned mainly with hand-held high pressure streams of water or water-based solutions or emulsions, often followed by scraping with shovels and other hand tools. Caustic soda solutions may be used too. Costs are very high and the cleanliness achieved is often marginal or unacceptable. Residues are usually wasted and their disposal is a problem.
In our parent applications, Ser. Nos. 870,103 and 1,053, now U.S. Pat. Nos. 4,231,804 and 4,231,805, incorporated herein by reference, we have disclosed an economical process for stripping protective and residual coatings by means of a gaseous stripping composition wherein neither the gaseous stripping composition nor the surface being stripped is substantially above ambient temperature. While our process is surprisingly effective for removing almost all of such coatings, in some cases this process is slow for industrial use. Also, we have found that some coatings contain impurities or pigments which are insoluble in any practical stripping composition. For example, many oils and tarry substances, such as No. 6 Oil (Bunker C oil) and various tars and asphalts encountered in commerce contain small amounts of carbonized material and/or inorganic substances, such as rust particles, some of which are left on the surface, sometimes together with a small amount of the initial petroleum coating which is trapped in and around these particles after our process has been carried out. This residue generally amounts to less than 1% of the original coating and is usually unobjectionable; but sometimes, where a change of cargo is to take place, even such a minor amount of residue is undesirable.


A method is proposed in which groups are formed by first broadcasting a group definition message (GDM) in which a logical formula (LF) is included expressing conditions (C1-N) on classification parameters of terminals which may have to be included in such groups. Each of these terminals then checks for itself whether its classification parameters, such as individual and group addresses, satisfy this formula which consists in combining these conditions via logical operators (L1--(N-1)). If so, a dynamic group address (DGA) included in the group definition message is allocated to such a terminal such that it may subsequently be paged by using this dynamic group address. A specific use of this method in which these groups are used to efficiently arbitrate access of a shared transmission medium between the above terminals is also shown.

Such methods are already well known in the art, for instance from the European Patent Application EP-A2-0570937. Therein, the groups are formed by first paging each terminal individually to inform it that it is included in a group with a particular dynamic group address and, after having so paged each of the group members, by then addressing the thus formed group by using this dynamic group address.
The use of groups is a well established practice in particular in mobile communication networks wherein they are for instance used as in the known method to establish a group call via the paging message. Such groups and group calls have however a very wide application area that is neither restricted to terminal paging in a strict sense nor to mobile communication networks nor even, for that matter, to networks that use a so called shared transmission medium in general.
Indeed, on the one hand and as explained in detail later on; the paging message might contain control information for assigning to such a group specific access channels so as to reduce the collision probability or for assigning to such a group specific paging channels on which the terminals of a group are to listen in. The latter feature is advantageous in that it allows decreasing the time needed to page a group of terminals as well as reducing the amount of energy required in each of the terminals to listen in on the paging channels. Also, in conventional wired networks such groups might prove to be useful, for instance in implementing Universal Personal Telecommunications or UPT as with groups it is not necessary to pinpoint the exact location of the terminals of the groups when information has to be conveyed thereto.
In view of the above it may be appreciated that the possibility of defining such groups dynamically--as opposed to pre-assigning them to the terminals or to users thereof on their subscription--is extremely advantageous as the use of a large number of pre-assigned addresses can thus be avoided. Furthermore, the definitions of the groups may be adapted to take account of the present state of the network in which the groups are defined as well as of user or terminal mobility.
However, a major drawback of the above known method for forming dynamic groups is that it entails a large amount of signalling traffic to form each group. This signalling traffic furthermore dramatically increases with the number of groups and the number of terminals included therein and thus puts an undue burden on the network in which these groups are formed, particularly but not exclusively when a transmission resource available therein is scarce, such as for instance in mobile communications systems.

Method for forming groups of communication terminals and use of same


A hydrostatic slewing drive suitable for use in construction equipment, in particular excavators, has a pinion shaft that is rotationally mounted in a housing. A slewing pinion is connected to the pinion shaft. An axial piston motor that utilizes a swashplate construction is in the housing and has a rotating cylinder block with borings and pistons located in the boring. The cylinder block is in one piece with, or integral with, the pinion shaft. The axial piston motor preferably has a constant flow volume, whereby the swashplate is shaped on a housing component. The pistons are supported by slippers on the swashplate which is provided with hydraulic fluid supply channels to which borings in the slippers and in the piston can be connected. The slewing piston can be detachably fastened to the pinion shaft/cylinder block. There is also a brake that can be actively connected with the pinion shaft/cylinder block. The brake, which is a wet, spring-loaded, multiple-disc brake, is preferably located next to the swashplate base and is connected in rotational synchronization with the pinion shaft/cylinder block by a torsion rod. At least one valve, in particular a control valve, is located between the swashplate and the swashplate base.

1. Field of the Invention
This invention relates to a hydrostatic rotary drive suitable for use in construction equipment, such as excavators, with a pinion shaft that is rotationally mounted in a housing, a slewing pinion that is connected to the pinion shaft and an axial piston motor that uses the swashplate construction and has a rotating cylinder block with borings and pistons located in said borings.
2. Background Information
The slewing drives of the prior art for excavators generally consist of a high-speed axial piston power unit, a downstream one-stage or two-stage step-down gearing and a pinion shaft with a slewing pinion connected axially to it. A brake is also located between the axial piston power unit and the step-down gearing. Slewing drives of this type have been manufactured and sold since 1985 by Linde AG, Industrial Trucks and Hydraulics Division, Aschaffenburg.
The object of the invention is to make available a hydrostatic slewing drive of the type described above that has compact dimensions and is easy and economical to manufacture and install.


Briefly, in accordance with one or more embodiments, in response to receiving a single carrier signal that is not phase locked, channel equalization may be applied to the signal via a channel equalizer. The equalized signal may be phase averaged to provide a signal that is at least partially phase stabilized. The channel equalizer may then be trained by feeding back the at least partially phase stabilized phase reference to the channel equalizer. The resulting signal may then be decoded via coherent or quasi-coherent detection.

Digital data transmission is often accomplished using modulation schemes. For higher data rates, the equalizer complexity involved for single carrier modulation grows with the symbol rate and as a result multicarrier transmission schemes such as orthogonal frequency-division multiplexing (OFDM) typically are utilized instead. Many higher data rate systems such as systems compliant with a Wireless Fidelity (Wi-Fi) Alliance standard, a Worldwide Interoperability for Microwave Access (WiMAX) standard, a Digital Video Broadcasting-Terrestrial (DVB-T) standard, a Long Term Evolution (LTE) standard, and so on, use multicarrier modulation for this reason. Many of these systems are utilized in environments with heavy multipath propagation and/or dynamic fading, often wherein one or both of the link terminals are non-stationary. Even when the link terminals are stationary, dynamic changes in the environment, for example trucks passing by on nearby streets, may create rapid changes in the channel that challenge the synchronization capabilities of the demodulator.
Recent advances in video compression technology have greatly reduced the data rates involved to transport video data streams. Such advances have provided an opportunity to reduce the signal bandwidth used to transport video data. A reduction in signal bandwidth via compression allows certain benefits such as power concentration to increase link margin. Compression has also reopened the door for the use of single carrier modulation schemes since the equalizer complexity is more manageable at the reduced signal bandwidths. However, single carrier signal synchronization, especially carrier phase tracking, can be very difficult in fading conditions at the involved signal bandwidths which are narrower than the bandwidths for typical broadband systems, for example WiFi at 20 MHz or DVB-T at 8 MHz, and broader than the bandwidths for most cellular systems, for example 500 kHz to 1 MHz. At these intermediate signal bandwidths, both the narrow signal techniques used for many cellular systems and the broadband techniques used for higher-rate signals may be suboptimal.
It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

Single carrier communication in dynamic fading channels