An aerosol hazard classification and early warning network is composed of a large number of detector and analysis units, called xe2x80x9cdetector stations,xe2x80x9d which are deployed throughout a region to be warned of a potentially hazardous aerosol intrusion. Such aerosol threats may originate from fires, volcanic eruptions, or overt releases of biological and chemical agents dispersed in aerosol form. Among the former are the characteristic toxic aerosols released during refinery fires or explosions. The latter biological agents include bacterial spores, lyophilized bacterial cells, and virus preparations, whereas chemical agents might include various forms of nerve gasses and other anti-personnel gasses such as mustard, all commonly deployed in aerosol form. Each detector station contains an aerosol handling unit that samples and transfers ambient aerosol particles one-at-a-time through a light scattering chamber where each such particle is constrained to pass through a fine laser beam producing, thereby, an outgoing scattered light wave. The scattering chamber contains a plurality of scattered light detectors arranged to accept light scattered into different angular locations. The signals detected at each detector position are processed by a corresponding digital signal processing chip with the resulting set of digitized signals being transferred to an on-board central processing unit. The CPU analyzes the set of light scattering signals and identifies or otherwise characterizes each particle. The classification/identification data are then stored and, on preprogrammed command, telemetered to a remote xe2x80x9ccentral stationxe2x80x9d by means of an on-board telemetry unit. The central station analyzes the sets of data received from all the detector stations and then instructs, as necessary, selected detector stations via telemetric means to change their sampling and telemetry rates. As soon as sufficient data are available, the central determines the presence, threat, extent, and progress of the aerosol cloud. These factors are then telemetrically transmitted by means of alarms and warnings sent to potentially threatened regions.

The present invention is concerned with a method and apparatus for monitoring the progress and composition of a cloud of aerosol particles that had been released previously into the atmosphere. By xe2x80x9cprogressxe2x80x9d is meant position and concentration relative to a region for which said aerosol cloud may pose a health hazard.
Expressly incorporated herein are the following patents concerning means and techniques by which such aerosol constituents of the cloud may be classified and/or identified:
4,548,500xe2x80x94xe2x80x9cProcess and Apparatus for Identifying or Characterizing Small Particles.xe2x80x9d (Oct. 22, 1985).
4,693,602xe2x80x94xe2x80x9cMethod and Apparatus for Measuring the Light Scattering Properties of Small Particles.xe2x80x9d (Sep. 15, 1987).
4,710,025xe2x80x94xe2x80x9cProcess for Characterizing Suspensions of Small Particles.xe2x80x9d (Dec. 1, 1987).
Most of the aerosol particles present in the Earth""s atmosphere pose little or no health hazard. Even the occasional dangerous aerosol particle is of negligible importance because its concentration is so low However, when pathologically hazardous aerosol particles occur in great numbers, their potential to cause illness or injury increases dramatically The presence of high concentrations of such aerosol particles can occur naturally or from man made sources. Volcanic eruptions are examples of the former while accidental chemical plant releases and refinery plant explosions are representative of the later.
Other natural releases of potentially dangerous aerosols include those occurring during the rapid formations of photochemical smogs, often initiated by manmade contributions such as automobile exhaust products. The natural releases of fungal spores, such as Coccidiodes immitis, the causative agents of coccidioses, under the occasional environmental conditions needed to promote the rapid growth and maturation of the parent fungi, can have devastating effects on the health of those affected. Finally, there is a large range of potentially lethal aerosols that might be released by terrorist or military groups intent on inflicting great numbers of casualties. These include aerosols of both biological and chemical origin and their release is generally expected to be surreptitious.
When dangerous aerosol particulate clouds occur within or adjacent to populated areas, it is desirable to provide an early warning for the inhabitants that might be affected were they to inhale such aerosols. Such warnings can result in a dramatic reduction of casualties in spite of the possible unpredictable collateral responses, such as civil unrest due to fear or panic, by the endangered population. It has often been reasoned that by the time such aerosol threats are detected and identified, it is too late to issue a warning to the potentially affected population. This is not generally true.
Aerosol intrusions often occur as dispersals in the form of clouds released above the ground. For example, volcanic eruptions generally send huge quantities of material into the upper atmosphere from which the aerosol particles fall back to the earth and only affect the local populations once they reach near ground levels. In ambient air, a particle of radius 10xe2x88x926 m=1 xcexcm and density of 1 gm/cm3 would require almost 3 hours to fall just one meter. Thus with a suitably deployed warning system, the threat posed by such aerosols will be ascertained long before they reach altitudes or locations where their presence might cause injury.
There are many types of aerosols that are hariless. Obvious examples are water droplets or even fine ice mists. It is important that any viable warning system be able to differentiate between potentially dangerous aerosols and the more common harmless varieties.
The means by which aerosol threats to a local population be recognized is an important object of this invention. Obviously, for volcanic eruptions or chemical plant explosions or similar aerosol intrusions, the source and location of the resultant aerosol cloud is easily noted and tracking is often straightforward, except perhaps at night if visual means are used. This type of daylight tracking is generally passive and based on the observation of the effect of such intrusive clouds upon background illumination. Knowing the source of the cloud means that its composition is also known, at least initially. Instrumentation may be brought into the affected regions for purposes of local compositional monitoring that, eventually, forms the basis for evacuation planning if needed. Additionally, once a potentially threatening aerosol cloud has been detected, its monitoring may be achieved to some degree by optical or radio wave probing of the cloud using laser or radio sources at a safe distance from the threat.
A popular concept for providing warning of an aerosol threat is based on a traditional RADAR approach using laser produced radiation to probe the cloud threat at a distance. NASA had applied such techniques in their extensive measurement programs of 1989 through 1990 as a means for the profiling of aerosol and cloud backscatter, Doppler wind measurements, and the measurement of atmospheric trace species. Despite exceedingly large Federal expenditures in this area, the technique is not expected to yield any practical optical signals capable of permitting cloud composition to be deduced. Nevertheless, for clouds of known origin, composition may be deduced based on such a priori information. Ulich et al. in their U.S. Pat. No. 5,257,085 discuss many elements and variations of this technique for probing the physical properties of distant scenes by use of both active and passive interrogations.
The LIDAR (light detection and ranging) technique has various faults including requirements for an unimpeded view of the aerosol, i. e. without intervening particulates, atmospheric interferences, or opaque structures. Inferring aerosol concentrations from such LIDAR measurements of unknown particles is unlikely. Mixed aerosol compositions as well as size distributions that are changing in time illustrate further shortcomings of the concept. Esproles, in his U.S. Pat. No. 5,345,168, has explored some novel means for improving the information content in the returned LIDAR signal. Min et al. in their U.S. Pat. No. 5,102,218 discuss LIDAR measurements at very short ranges, generally less than 30 meters, for extracting target signatures from mixtures of target components and naturally occurring aerosol particles. The referenced patent""s detailed description includes many references to the target aerosol discrimination techniques used for so-called active optical proximity sensors together with extensive discussion of the then-current state-of-the-art.
Stewart et al. in their U.S. Pat. No. 4,687,337 discuss the need to deduce the extinction coefficients of aerosol particles by means of instrumentation taken to the various sites to be studied. Such so-called point source or in situ measurements are contrasted in their patent to the conventional LIDAR measurements. However, bringing instrumentation and personnel into regions thought to contain dangerous aerosol particles is usually avoided. For this reason, remote-sensing techniques for probing suspected targets have always been considered preferable. Carrieri in his U.S. Pat. No. 5,241,179 discusses this requirement in greater detail explaining the research programs of the U. S. Army Research, Development, and Engineering Center from the 1960s. The objective of these programs was the development of remote sensors xe2x80x9c. . . for detecting threat chemical and biological agents in vapor cloud, aerosol, rain, and . . . xe2x80x9d as surface contaminants. A need for passive spectroscopic techniques was recognized in the early 1970s. Such techniques would collect and process radiance from natural or preexisting sources.
Advanced development on a remote chemical agent detection unit began in 1979. As of the filing of the Carrieri patent in late 1992, the differential scattering/differential absorption LIDAR devices, referred to simply as DISC/DIAL devices, were said to show the most promise and were considered the most technologically advanced vapor detection and range resolution systems currently in operation. Carrieri""s invention purported to extend these capabilities by means of a related standoff detection technology that could sense contaminants on/within terrestrial and manufactured surfaces using their infrared absorption/emission signatures permitting, thereby, personnel xe2x80x9c. . . to protect themselves and take appropriate action to decontaminate, or avoid contaminated areas altogether.xe2x80x9d These concepts still represented a far cry from the initial objectives for the remote characterization of aerosol particles and associated biological agents. There can be no doubt, reading these reports and the associated instrumentation descriptions, that ultimately some form of in situ detection and analysis would be needed.
Muran et al. hoped to address the need for in situ monitoring by means of their invention filed in 1998 and issued as U.S. Pat. No. 5,898,373. The method disclosed provides for the seeding of the regions to be interrogated at some future time with xe2x80x9c. . . sticky polymeric particlesxe2x80x9d that would adhere to the various local surfaces for long periods of time. Using spectrophotometer equipped airborne vehicles, the reaction of these specially prepared particles with dangerous chemicals or particles would produce characteristic emissions capable of detection by the airborne instrumentation. Alternatively, the region seeded with the sticky particles could be scanned from above using active laser systems to induce excitation emissions from the materials/particles xe2x80x9ctrappedxe2x80x9d by or adhering to the sticky particles. The sticky particles would be designed to incorporate suitable chemicals that would react with the target agents resulting in a unique photometric signature of the selected target candidates. The ability of these particles to be observed at the moment of their deployment could be considered fortuitous, at best, since each threat must have to have been anticipated by the appropriate deployment/seeding of a unique detector particle
Much Federal finding has been directed during the past 50 years to problems associated with the protection of military personnel from aerosol threats, usually in the form of biological and chemical weapons. Small portable field instruments that would be able to identify small samples with great speed have received considerable support. Additionally, the hope to develop xe2x80x9c. . . revolutionary point-detection technologies . . . that [include] detection devices [that] can be small (hand-held) instruments for individual soldier use . . . xe2x80x9d has long been sought by the Government for protection of military personnel. The quotation referenced above is from a late 1999 request for proposals by the Defense Advanced Research Projects Agency (DARPA) in which they delineate their so-called xe2x80x9cwish list.xe2x80x9d Although the concept of networking such devices is suggested, portability in the field is stressed.
Unfortunately, the DARPA emphasis, discussed above, falls short of a practical approach in several regards: First, is the lack of a warning system for purposes of alerting the civilian population of an impending threat. The first detection with such DARPA devices would occur when the individual carrying the device enters the field or is enveloped in the threat cloud. There is no attempt to develop an early warning system. Next, this particular procurement devotes extraordinary attention to the need of avoiding false positive alarms despite the fact that the mere presence of a biological aerosol itself is cause for immediate concern and alarm. Naturally occurring biological aerosols are extremely rare events.
Key to any warning system is the ability to detect the aerosol threat as soon as possible after it has been released. Once an aerosol threat has been released, the local concentrations of the offending particles are extremely high. For example, it has been estimated recently, following the analyses of the Russian anthrax accident at their Sverdlovsk facility, that about 10 viable spores of B. anthracis are required in the lungs of a healthy individual to cause disease. This would require ambient concentrations of the order of tens of thousands per liter of air. To achieve such concentrations, the aerosol concentrations near the release zone would require the presence of at least 106 to 107 per liter of air. Accordingly, near the release point, classification/identification becomes a much-simplified task because of the expected similarity of each member of the aerosol cloud ensemble. Finding a suitable signal becomes far simpler if detection is prompt and close to the release: an objective of the present invention. In such a huge collection of positively identified aerosol particles, the probability of misclassifying the entire ensemble, and thus the detected event itself, becomes vanishingly small. It is a major objective of the present invention to focus xe2x80x9con the forest,xe2x80x9d so to speak, rather than a particular xe2x80x9ctree.xe2x80x9d
Additional emphasis of the DARPA procurement, which is typical of those issued by the Federal Government during the prior 30 years, is placed upon the need to differentiate between live and dead biological particles in the threat aerosol cloud. The belief that confirmation of the fact that because a threatening aerosol contains an overwhelming quantity of dead microorganisms, there are no remaining dangers associated with the trace viable cells cannot be considered a valid analysis of such a threat. The detection of the presence of potential pathogens, irrespective of their viability, is an essential element of any early warning system.
Threats associated with chemical agents are addressed also by various Federal procurement activities. One of the more interesting is the Shipboard Automatic Liquid Agent Detector (SALAD) program whose specification and related solicitations have long been in progress. xe2x80x9c. . . The SALAD acquisition program has been initiated to provide the Navy with the capability to automatically detect liquid chemical warfare agents. This acquisition program has been underway for approximately five years during which the Government has developed and produced a prototype SALAD that has been analyzed and tested to confirm its potential to meet Navy operational requirements . . . xe2x80x9d Later, within the specifications, it is stated xe2x80x9c. . . The SALAD shall automatically detect liquid nerve (G- and V-series) and blister (H- and L-series) agents at the concentrations and droplet sizes as follows:xe2x80x94concentration: 2.0 mg/m2 and higher-droplet size: median mass diameter of 500 micrometers and larger {Objectivexe2x88x92200 micrometers and larger} . . . xe2x80x9d What is particularly striking about this activity is the enormous size associated with the median size: 500 xcexcm. At this size in ambient air, the particle will fall I meter in about 22 seconds. The detection system has 60 seconds to make an identification of the agent and issue a warning within which time the particle would have fallen almost 3 meters. Detection issues are complicated farther by the ship""s motion as well as ambient wind effects on moving the agents. Associated with such large particles are expected to be smaller particles that may well be undergoing evaporation. It is this latter fraction of a deployed chemical agent aerosol that would be most usefully detected since the aerosol""s associated size distribution would be changing in time. It is a further objective of the present invention to monitor the size distribution and its changes with time as a means for detection of such agents. Natural aerosols comprised of water particles would exhibit similar behavior except for a very important and easily detected difference: the refractive index of water droplets is expected to be about 1.33 in contrast to that of a typical chemical agent. The present invention will extract the refractive index of selected aerosol particles as required from their recorded light scattering characteristics.
It is an object of the present invention to provide an explicit means to detect and monitor the composition of a potentially threatening aerosol cloud arriving at remote locations by remotely positioned detector means. Such detectors, called xe2x80x9cdetector stations,xe2x80x9d are capable of performing a set of scattered light measurements by which the target aerosol particles are well classified and/or identified, one-at-a-time, at each locale where they are detected. Each detector station transmits its collected and processed information by telemetric means to a central station that is responsible for further processing of the received data. Important among the latter processing activities is the prediction of the movement of all elements of the aerosol cloud.
Another objective of this invention is to process further the reduced data received by transmission means from each deployed detector station to permit prediction of arrival time and threat danger to sites not yet exposed to said aerosol cloud. A means by which air mass movement could be followed is described in U.S. Statutory Invention Registration # H111 issued Aug. 5, 1986 to Barditch et al. Their tracking technique seems of little practical consequence since they must seed the air mass to be monitored at one location with Bacillus thurengiensis spores and then culture a sample of air collected at a second location. The subsequent growth on a specially prepared culture plate of the seed spores confirms the origin of the sampled air and the numbers recovered a measure of the diffusion of the seeded sample during its journey. This method is inapplicable as a warning system and requires the a priori detection and location of the aerosol threat. Sometimes, should the aerosol threat be detected or noticed and if it is known to contain spores or other culturable organisms, such sampling may provide a historical record of the threat, but no warning. Interestingly, and as a consequence of the present inventive method, the bacterial spore seeding implementation of Barditch et al. could easily be replaced thereby using polystyrene latex spheres of nominal diameter 1 xcexcm. Since such particles are readily detected in real time with an element of the present invention, results can be almost instantaneous since no time- and labor-consuming culturing would be required.
Another objective of the invention is to provide rational central station decisions, based upon analyses of all data collected from the set of deployed detector stations, to provide an alarm and/or warning of the expected arrival time of the dangerous aerosol cloud and its probable composition and suggested means for protection of the soon-to-be-exposed populations. This alarm and warning is prepared for each locale on an individually calculated basis. Thus one region might be given a ten-minute warning whereas another simultaneously might receive a two-hour warning. Each such report to each specified locale is updated in a timely manner and communicated to each potentially affected locale to insure maximal warning for the threatened population.
A further objective of the invention is to use the central station to regulate data collection and analysis rates at each detector station, collectively or individually, by telemetry means.
There are many different means for characterizing aerosol particles at a fixed location. For example, Cole in his U.S. Pat. No. 5,296,910 describes the use of multiple force fields combined with Doppler velocimetry to obtain particle density, diameter, electric charge, magnetic moment, and other physical attributes of individual particles. Gerber in his U.S. Pat. No. 5,315,115 describes optical means of determining particulate integrated properties that could then be used to classify an aerosol in terms of its integrated volume concentration, integrated surface area concentration and aerosol extinction coefficient in the infrared spectral region. The text xe2x80x9cModern methods of particle size analysisxe2x80x9d edited by Howard Barth (Wiley-Interscience, New York 1984) discloses a large number of techniques by which the aerosol particle sizes may be determined. Theodore Provder has edited several collections of papers for the American Chemical Society Symposium Series on the analysis and characterization of particles and particle size distributions under the title xe2x80x9cParticle size distributions I, II, and IIIxe2x80x9d in 1987, 1992, and 1998. There are literally hundreds of texts and thousands of scientific articles on related topics of particle characterization. There is, however, one technique with the greatest breath of application for aerosol particle characterization.
The most powerful technique for differentiating and characterizing individual aerosol particles is by means of light scattering. In their broadest sense, light scattering measurements are performed using a collimated monochromatic light beam through which the particles pass, generally one-at-a-time. During its transit through the beam, a particle scatters some of the light incident upon it. This scattered light is then collected by means of collimated detectors positioned at discrete scattering angles with respect to the direction of the incident light beam. Each detector may be fitted with various optical elements including polarizing analyzers, interference filters, electrooptical shutters, neutral density filters, waveplates, and other optical elements. Even in its simplest implementation, with all detectors lying in a plane and no analyzer at any detector, Wyatt and his co-workers have demonstrated the powerful characterization capabilities of the technique including the following:
For determining the refractive index and size of simple, homogeneous polystyrene latex particles
xe2x80x9cMeasurement of the Lorenz-Mie Scattering of a Single Particle: Polystyrene Latex,xe2x80x9d with D. T. Phillips and R. M. Berkman, J. of Colloid and Interface Science 34, 159 (1970):
For the study of bacterial spores
xe2x80x9cDielectric Structure of Spores from Differential Light Scattering,xe2x80x9d Spores V, American Society for Nicrobiology, (1971);
xe2x80x9cObservations on the Structure of Spores,xe2x80x9d J. Applied Bacteriology 37, 48 (1975);
For the detection and characterization of photochemical smog particles
xe2x80x9cSingle Particle Light Scattering Measurement: Photo-Chemical Aerosols and Atmospheric Particulates,xe2x80x9d with D. T. Phillips, Applied Optics 11, 2082 (1972);
For differentiating aerosolized bacterial cells
xe2x80x9cStructure of Single Bacteria from Light Scattering,xe2x80x9d with D. T. Phillips, J. Theor. Biol. 37, 493 (1972);
For measuring the accretion of acid-like coatings on aerosol particles generated by power plants
xe2x80x9cSome Chemical, Physical and Optical Properties of Fly Ash Particles,xe2x80x9d Applied Optics 14, 975 (1980);
The detector system described in U.S. Pat. No. 4,693,602 by Wyatt et al., as well as in the paper:
xe2x80x9cAerosol Particle Analyzer,xe2x80x9d with Y. J. Chang, C. Jackson, R. G. Parker, D. T. Phillips, S. D. Phillips, J. R. Bottiger and K. L. Schehrer, Applied Optics 27, 217 (1988),
represents an early version of a more general detector incorporating out-of-plane measurements as well as depolarization analyzers. This earlier device as disclosed and implemented was very large, requiring an argon-ion or HeCd laser as an illumination source and individual photomultiplier detectors connected to a read head by means of optical fibers. Accordingly, it had a very high power consumption that made it difficult to operate on battery supplies for extended periods of time. The photomultiplier power supplies and assorted computer and aerosol handling systems added further bulk and cost to the analyzer making it impractical for any type of field deployment.
In order to monitor successfully potentially dangerous aerosol threats and differentiate them from harmless constituents, a large number of individual light scattering detector stations must be placed strategically around and throughout the region to be protected. Although the concept of a xe2x80x9cpoint sourcexe2x80x9d detector, i. e. one that is localized and restricted in its range of detection, has been recognized for many years, the concept of linking such detectors cooperatively in a network and providing individual detectors the means to function filly and independently in classifying the local aerosols it may sample has not been considered previously and represents a further objective of this invention.
Networked detectors have been used extensively for telecommunications purposes and similar techniques of lid localized detector units have been used frequently to provide fire and intruder protection for buildings and similar regions. Such so-called wireless warning systems employ a variety of signal processing techniques to insure high reliability. For example, Sanderford et al. in their U.S. Pat. No. 5,987,058 employ a spread spectrum technology with high reliability for the continuous monitoring of a building. Sheffer et al. in their U.S. Pat. No. 5,568,53 5 describe explicitly a cellular alarm unit that includes cellular phone functions permitting cellular connections to remote monitoring stations. The remote monitoring stations detect an emergency condition by means of sensors that preferably include fire sensors, perimeter sensors for detecting opening of doors or windows, for example, and a panic switch for activation by an individual within the enclosed area in the event of a medical or other emergency. The Sheffer et al. system is intended to circumvent more conventional hard-wired systems that are easily defeated by severing the traditional telephone wiring. There are many other types of alarm systems that provide for efficient, cost-effective and reliable cellular-type radio/telephone communication system included within an alarm system to provide wireless communication such as described by Smith et al. in their U.S. Pat. No. 4,993,059.
All of the aforementioned alarm systems that make use of a network of cellular or other wireless intercommunications means are based on sensors intended to detect and then warn of a class of easily monitored phenomena. Most important among these are fire and smoke detection, intruder presence, physical parameters such a temperature and humidity, panic alarms, television monitoring stations, radiation detection, etc. As will be evident from the detailed description of the present invention, the sensors used therein are both distinct and uniquely different from sensors of these types in the following ways: the sensors provide for data collection and real-time processing and analysis; the sensors incorporate a variety of electrooptical elements as well as a fully functional microprocessor; they can be reprogrammed, the sensors include means for sample handling.
Each station must be capable of processing the data it collects and telemetering the results to a central station that would collect such results from all stations for subsequent analysis and make decisions concerning alarms or other warnings. Despite the existence of a wide range of analytical tools for the counting, sizing and classifying aerosol particles, there has been no attempt to integrate some of these tools with a means for appraising the threat of an aerosol intrusion and alerting the targeted population of the need to protect itself. The present invention discloses a straightforward means by which this may be achieved.
The invention disclosed here describes a means, comprised of an array of light scattering detector stations and their ancillary electronic and physical infrastructure, by which communities, buildings, compounds, military bases, airports, embassies, parks and other selected regions may be warned of the presence of an impending aerosol threat. Key to the successful operation of such a system are detector stations capable of preparing ambient air samples for measurement, measuring and classifying aerosol particles therein one-at-a-time using multiangle light scattering over a broad range of discrete scattering angles, identifying specific threat subclasses from the data so-collected and analyzed within the collected aerosol sample, counting relative numbers of such subclasses, monitoring physical changes that may be occurring throughout the analysis period, and reporting all processed data via integrated telecomnunications links to a central control station.
Each light scattering detector station includes a scattering chamber traversed by a fine laser beam, together with the capability to: dilute the sampled aerosol stream so that only a single particle is in the beam at any moment; make light scattering measurements on each transiting particle over a broad range of discrete scattering angles using detectors that may incorporate polarization and fluorescence analyzers; and, process the data collected identifying, thereby, the type and class of each aerosol particle measured. Data processing and classification are achieved using an integrated microprocessor system that contains random access memory and read only memory incorporating the preprogrammed software required for particle classification. In addition, each such station has a compact transmitter similar in concept to the GHz transmitters used by conventional cellular telephones.
Each detector station, which has been sited previously to form a component of a multi-detector network spanning the region to be monitored, is connected via a telecommunications link to a central station The central station receives and processes all data transmitted from the linked detector stations. On the basis of such processed data, the central station monitors the aerosol cloud""s position and composition, evaluates all potential threats to the region being monitored, commands specific detector stations as required to change or modify such detectors"" specific collection rates and processing, and issues alarms and/or near real-time warnings to subregions of any potential problems expected from the aerosol cloud.

Aerosol hazard characterization and early warning network


A lubrication management system controls the lubricant quantity in multiple refrigeration compressor lubricant sumps. A buoyant member is placed in the lubricant, where a float portion and a magnetically conductive portion rise or fall together. The sensor further includes a displacement transducer producing a variable electrical signal through a resonant frequency shift. The displacement transducer, in proximity with the magnetically conductive portion of the buoyant member, transforms motion of the magnetically conductive portion to changes in resonant frequency shift in proportion to the position of the magnetically conductive element relative the displacement transducer. The system also includes circuitry for receiving the signal and comparing the signal to an adjustable set point, from which the circuitry determines whether an output for signalling a need for additional lubricant is necessary. A solenoid valve may be opened in response to the circuitry output to feed lubricant to the sump from a remote reservoir.

1. Field of the Invention
A lubrication management system is disclosed for the operation of machines requiring a minimum level of lubricant in a lubricant sump. More particularly, a lubrication management system for refrigeration system compressors utilities a float member with a magnetically conductive portion in combination with a displacement transducer to provide an automatic feedback signal to a circuit for control of a normally closed solenoid valve in selective communication with a lubricant reservoir, such that the circuit can control the level of lubricant in the sump through replenishment from the reservoir to at least a minimun required level.
2. Description of the Prior Art
In commercial and industrial refrigeration systems, particularly units with parallel compressors, there is a need to accurately control the lubricant level in the compressor's sump or crankcase. Most refrigeration compressors utilize liquid lubricants for lubrication and internal cooling. The compressor is the heart of a refrigeration system and the most expensive component, typically costing more than all the other parts combined. If the proper lubricant level is not obtained and maintained (i.e., a lubricant sump level that is too high or too low), the compressor can be quickly destroyed through "burn-out" (the insufficient lubricant condition) or rendered grossly inefficient or "slugged" (the excessive lubricant condition).
Moreover, insufficient lubricant and resulting compressor "burn-out" can cause contamination of the refrigerant system and refrigerant plumbing. Cleaning out a refrigeration system contaminated with from a "burn-out" can often be one of the most costly service charges a unit will ever require other than replacement of the compressor. Indeed, all refrigeration compressors pass or "pump" lubricant through their refrigerant discharge lines due to machining tolerance limitations, the refrigerant fluid's miscibility with most lubricants, overall compressor design, pressure drops across the sump and various other design or system factors.
This lubricant contamination of the refrigerant discharge lines is even more significant with parallel compressor systems which utilize several refrigeration compressors, usually of a semi-hermetic type, sharing a common suction and discharge line. When lubricant is inadvertently pumped out of the compressor sump into the refrigerant circuit, the lubricant is directed through the system's evaporator, expansion valve, and condenser, and is eventually returned to the compressors still entrained in the refrigerant. Since such parallel compressor configurations share a common refrigerant supply or suction line and a common suction manifold at different locations while often operating under different duty cycles, the returning refrigerant (and lubricant contaminant) does not necessarily return to the exact compressor from whence it came at the same rate or quantity. In the presence of a common suction line and different duty cycles, lubricant can move from one compressor to another. Thus, minimization of lubricant contamination of the refrigerant and plumbing is a very high priority of virtually all systems.
A reverse contamination process is also possible, where the feed lubricant may contain entrained refrigerant. When lubricant is allowed into the compressor sump, it is possible that this contaminated refrigerant will circulate within the sump and be drawn into the compression chamber of the compressor. The common refrigerant supply or suction line and a common suction manifold can thus be further contaminated with undesirable lubricant.
One or more lubricant separators are commonly used on the compressor discharge lines to lower the amount of lubricant lost to the refrigerant. The lubricant is captured by the lubricant separator and returned to a common remote lubricant reservoir, previously filled with a large pre-charge of lubricant. The lubricant in the common lubricant reservoir is then ready to be returned to the individual compressor sumps as needed.
Over the years, there have developed several methods to maintain a minimum level of lubricants in the compressor sumps, as well as generally any fluid in a containment vessel. Such methods have been especially devoted to the needs of internal combustion engines and compressors, where hydraulic delivery of lubricants such as oil to the machine elements in relative motion is an absolute necessity in avoiding premature wear of the moving elements. Typically, such machines incorporate a sump or similar containment vessel placed in the lower regions of the machine for storage of the lubricant while a separate lubricant portion is circulating throughout the machine and delivered to the machine elements likely to experience wear. Thus, as a minimum level of lubricant in the sump is necessary to maintain the wear reducing and cooling function of the lubricant, it is often necessary to replenish the sump with additional lubricant during or after machine operation in the face of the lubricant losses caused by the reasons stated above. To properly accomplish this replenishment and lubricant management, it is first necessary to measure the existing level of the lubricant in the sump.
The most basic method of managing the level of lubricant in the sump as described above is through a dip stick or sight glass. With a dip stick, the level of oil is measured by the insertion of a stick of known and calibrated length into the lubricant sump a known and fixed distance. The level of the lubricant, adhering to the stick when the stick is withdrawn from the sump, can be readily determined by the length of adhered lubricant on the stick compared to the calibration marks on the stick. Such methods, although extremely commonplace, suffer from the disadvantage that only the oil existing in the sump at the time of the measurement can be determined. Subsequent loss of lubricant, such as through leaks, will not be determined until subsequent dip stick measurements are taken. Moreover, if it is determined that lubricant must be added, this addition must occur as a separate step and is often a messy and imprecise undertaking. In extreme cases, overfilling of the lubricant sump can create hydrolocking of the machine, where the pump hydraulically delivering the lubricant is caused to attempt to compress a column of lubricant, an essentially incompressible fluid. Severe structural damage is often caused during such events. Further, where multiple machines are in service, a common arrangement for stationary installations such as refrigeration system compressors, the need for more frequent attention increases.
Subsequent refinements include the use of lubricant pressure sensors in conjunction with the use of dip sticks. The pressure sensors measure the pressure generated during the hydraulic delivery of the lubricant to the wear elements, typically through comparative resistance sensors or piezo electric transducers. If the pressure drops below a predetermined level, the sensor indicates that the lubricant sump is in need of additional lubricant. However, such systems usually signal the need for additional lubricant only after an extreme need arises and are incapable themselves of adding the additional lubricant necessary.
Alternatives to dip stick methods include sight glasses provided in the side of the sump itself. Usually provided in stationary engines or compressors, visual inspection of the sight glass allows an operator to continuously monitor the level of lubricant in the sump and take appropriate action to add lubricant if the level falls below some predetermined level. However, such systems again only provide an indication of the need for additional lubricant and are incapable themselves of adding the additional lubricant necessary. Thus, operator attentiveness is a further requirement, especially in the presence of foam often occurring through churning of the lubricant due to the motion of operating elements therein.
As an alternative to purely manual systems, mechanical float systems were developed and applied to lubricant sumps, especially where multiple machines are in operation and the use of a central lubricant reservoir can be used to service the separate lubricant sumps of several machines simultaneously. Each of the lubricant sumps is provided with a float in fluid communication with the lubricant in the sump and mechanically linked with a float valve interspersed between the common reservoir and the individual lubricant sump. When the lubricant level in the sump drops below a predetermined level, the float mechanically linked with the valve opens the valve and allows lubricant to flow from the common reservoir to the lubricant sump in need of replenishing. Such a device is disclosed in U.S. Pat. No. 4,428,208 to Krause.
These mechanical float valves, however, are not very accurate and have a high failure rate due to compressor sump pressure pulsations and vibration. If failure of the float valve occurs and the compressor lubricant level drops, insufficient lubricant can result in "burn-out" due to main bearing scoring and/or input motor overheating.
Moreover, liquid refrigerant mixing with the gases in the sump and contributing to foaming of the lubricant in the sump can open the float valve and cause false feeding of lubricant into the sump. A high lubricant level of liquid refrigerant in the crankcase can cause the compressor to "slug" as lubricant is encouraged to enter the compressor compression chamber, which is designed to compress only a vapor. Excessive liquid pressurization caused by such a "slug" can damage a compressor's pistons, rings, connecting rods, crank shaft, or exhaust valves.
Moreover, such mechanical float valves typically have metal seats and valve needles, in an effort to improve durability in the presence of the compressor's pulsations and vibrations. Such needle valves are not "bubble tight" upon closure and can allow refrigerant to enter the compressor's sump through the lubricant feed and introduce lubricant-entrained refrigerant into the common discharge lines and to the common suction manifolds as described above. This can decrease system capacity. Moreover, transient lubricant level fluctuations tend to cause opening of the needle valve which can, in some instances, result in overfilling of the lubricant sump, creating the potential for hydrolocking the machine or "slugging" as noted above.
Optical sensors have also been recently developed for application to sensing the level of lubricant in lubricant sumps. An example is U.S. Pat. No. 5,103,648 to Barier. Therein, an optical sensor is used in conjunction with a sight glass to determine the level of the lubricant in the sump. When an insufficient lubricant level is determined, a solenoid valve in combination with the sensor is activated to allow additional lubricant into the sump and thereby replenish the quantity of lubricant in the sump to safe levels. However, it has been found with such optical systems that foaming of the lubricant can result in a false signal calling for the addition of lubricant when none may be needed. Further, the optical units have a high maintenance and failure rate and a low repeatability due to contaminants in a refrigeration system's working environment and compressor vibrations.
In additional to optical systems, capacitance and inductive sensors have been tried, but have been found unsatisfactory as they do not capably distinguish between lubricant, liquidified refrigerant, foaming lubricant, various types of lubricants and refrigerant, contaminated systems, or any of these combinations.


An optical recording/ reproducing method which is characterized by irradiating a magnetic material having a perpendicular anisotropy with a laser beam to cause a change in the perpendicular anisotropy in the magnetic material to a non-perpendicular anisotropy thereby to record information; and by reproducing the information by detecting a change in a magneto-optic effect such as the Kerr effect. Also disclosed are an optical recording material and an optical recording device for use in the optical recording/reproducing method.

The present invention relates to write once type optical recording and optical recording/reproducing methods using a laser beam, and an optical recording material and an optical recording device using the methods. More particularly, the present invention relates to optical recording and optical recording/ reproducing methods useful for a high recording density, and an optical recording material and an optical recording device using the methods.
There are enhanced needs for file memories of high density and capacity in accordance with higher development of the information society. An optical recording is noted as the memories for satisfying the needs. This optical recording is divided into read only type, write once type and erasable type, which are properly used for individual applications. Here, the write once type optical disc uses a chalcogenide as its recording material and is formed with pores when irradiated with a laser beam. The recording is carried by making use of a change in reflectivity due the pores.
The present investigation of the write once type optical disc is centralized for improving the recording density. For this improvement, it is conceived to form minute recording pits by using a laser beam having a short wavelength and to use a pit edge recording together. It is, however, difficult to form pits having a satisfactory shape from the existing materials.
An improved optical recording medium is disclosed in U.S. Pat. Nos. 4,176,277 and 4,405,862. This optical recording medium has a structure, in which a thermal sensitive film and an absorption film are laminated. The absorption film absorbs the recording beam and changes it into heat, which is diffused in the thermal sensitive film for the recording operation.
The prior art thus exemplified has a limit in forming recording pits of about 1 .mu.m, thus leaving a problem that the improvement in the recording density is limited.

Optical recording/reproducing by changing perpendicular magnetic anisotropy to non-perpendicular magnetic anisotropy


An object storage receptacle having two articulating arm members movably attached to opposite sides of a receptacle member at a point at or above the center of gravity of said receptacle member. The articulating arm members are attached to the receptacle member such that in a first position the arm members form a handle by which the storage receptacle may be carried, in a second position the arm members form a stand sufficiently stable to support the storage receptacle in a free-standing manner, and in a third position the arm members together may be disposed laterally relative to the storage receptacle. The arm members may be capable of free movement throughout a continuous circle about the receptacle and/or capable of telescoping into a first position where the arm members are fully extended for use and in a second position where the arm members are fully retracted for storage. Wheels may be attached to at least one arm member to enable the user to roll the device to a different location during use without lifting and carrying the entire device.

Most household projects require the worker to use a variety of tools and materials during the course of the project. It is desirable to have assembled together in one place before beginning the project all of the tools and materials that are needed to complete the project. In addition to standard toolboxes, which, although easy to carry, are not suitable for many applications, 5-gallon buckets provided with "caddy" inserts are commonly used. However, these buckets are usually placed on the floor, which may require repeated stooping to retrieve tools and/or materials and to return them to the bucket when done. In addition, due to the weight of the tools and materials needed for the project, the bucket may be very difficult and cumbersome to move around as the project progresses.
In a related manner, in order to master the game of tennis, the general recommendation is to perform repetitive drills that simulate actual shotmaking. This requires that a sizable ready supply of balls be kept close at hand. However, merely using a storage bin placed on the court surface is impracticable, as it subjects the player and/or instructor to repeated and strenuous stooping to obtain balls for use in the practice. Further, whether these drills are performed alone, with the aid of an instructor, or with an automatic ball serving machine, a large number of tennis balls end up strewn about the court during the course of such practice. To retrieve all of these balls also requires repeated and strenuous stooping. This situation led to the development of ball retrieval and storage devices to minimize this labor.
A typical ball retrieval and storage device is disclosed in U.S. Pat. No. 3,371,950 to Stap entitled "TENNIS BALL RETRIEVER AND STORAGE UNIT" and issued 5 Mar. 1968. The '950 device includes a roughly cube-shaped ball receptacle having U-shaped rigid arm members movably attached in parallel to opposite sidewalls of the receptacle. The U-shaped arm members serve in an upright position as a standard for the receptacle and in an inverted position as a handle for the receptacle. The receptacle has a bottom formed from a plurality of parallel rods spaced apart from one another slightly less than the diameter of the balls to be retrieved, so that a tennis ball may be squeezed between the bars to gain entry into the receptacle. To retrieve a tennis ball from the court surface without stooping to pick it up manually, a person carrying the receptacle by the handle formed when the U-shaped arm members are brought into the inverted position presses the receptacle bottom against the tennis ball resting on the court to automatically squeeze the balls into the receptacle.
A modification of the '950 device is described in U.S. Pat. No. 4,412,697 to Verde entitled "TENNIS BALL RETRIEVING STORAGE CONTAINER" and issued 1 Nov. 1983. The '697 device merely comprises the separation of the plurality of parallel rods forming the bottom of the receptacle to a distance slightly more than the diameter of the balls to be retrieved and the addition of freely rotating hollow, cylindrical tubular rollers axially journaled about the parallel rods such that the distance between inside surfaces of adjacent parallel rollers is slightly less than the diameter of the balls to be retrieved.
Other known devices modify this concept. For example, U.S. Pat. No. 5,368,351 to Cuti, entitled "TENNIS BUTLER" and issued 29 Nov. 1994, and U.S. Pat. No. 5,294,161 to Stap, entitled "TENNIS BALL RETRIEVING AND STORING DEVICE" and issued 15 Mar. 1994, both show a receptacle having a handle/standard member or members such that the receptacle can be used to retrieve and store tennis balls. In addition, rolling carts capable of picking up tennis balls are shown in U.S. Pat. No. 4,461,504 to Perez et al. entitled "TENNIS BALL RETRIEVER AND CARRIER" and issued 24 Jul. 1984 and U.S. Pat. No. 5,301,991 to Chen et al. entitled "TENNIS BALL RETRIEVER AND STORAGE CART" and issued 12 Apr. 1994.
These and other currently known tennis ball retrievers have several disadvantages. First, because they are constructed entirely or substantially from metal or other dense materials, these devices are usually quite heavy, even when empty. Second, because the arm members used to form a handle and a standard, depending upon their position, are restricted in their movement, the devices are awkward to move when full. Third, the known devices occupy a large volume of space, due chiefly to the area occupied by the arm members. Although the arm members of several of the known devices are removable, it is inconvenient to have to disassemble the unit in order to store it, only to have to reassemble the unit for its next use.
Accordingly, it is an object of this invention to overcome the above illustrated inadequacies and problems of extant devices by providing an object storage receptacle that is lightweight, simple to use, and easy to store.
It is another object of this invention to provide an object storage receptacle having arm members capable of free movement throughout a continuous circle about the receptacle.
It is a further object to provide an object storage receptacle having arms capable of telescoping into a first position where the arm members are fully extended for use and in a second position where the arm members are fully retracted for storage.
It is another object of this invention to provide an object storage receptacle having wheels attached to at least one arm member to enable the user to roll the receptacle to a different location during use without lifting and carrying the entire receptacle.

Storage receptacle with integral handle/stand


Technologies directed to dynamic memory reallocation and offload channel state information (CSI) processing for device power savings are described. A method includes receiving, by a radio, first data from a processing device. The first data is sent to a second wireless device over a wireless channel. The method measures, by the radio, first CSI values that represent channel properties of the wireless channel. The method sends, by the radio, the first CSI values to the processing device with a first periodicity. The method receives, by the radio from the processing device, second data that specifies a transfer interval and an amount of memory to reserve in a memory buffer for second CSI values measured during the transfer interval. The method measures, by the radio, the second CSI values and sends the second CSI values to the processing device at the end of the transfer interval.

Many buildings, such as homes, retail stores, business centers, and the like, have a growing number of wireless transmission devices, including wireless transmitters and wireless receivers. These devices send an increasing amount of radio frequency (RF) energy through the buildings from many different directions. In addition, Wireless RF signals may be used in motion detectors to help detect human presence.

Dynamic memory reallocation and offload channel state information (CSI) processing for device power savings


A method and apparatus for increasing the entropy of a pseudorandom number (PRN). An intervener unit receives one or more signals from an authenticating device during a false authentication attempt. The intervener unit generates, in response to the one or more signals, a first PRN with an associated level of entropy, and transmits the first PRN to the authenticating device. The entropy level of the first PRN causes the authenticating device to generate during a subsequent authentication attempt a second PRN with a greater level of entropy than the first PRN.

Cryptography is the science of information security in which cryptographic systems are developed to protect data from unauthorized requesters. One aspect of cryptography is encryption, which provides data confidentiality. With encryption, a computer system converts input data, e.g., text or video content, into encrypted data, commonly referred to as cipher data. The cipher data is transmitted to another computer system, which cannot decrypt the cipher data without the proper key.
Another aspect of cryptography is authentication, which protects the access to data. Authentication involves a process to determine whether a requester is authorized to have its request fulfilled, e.g., whether the requester is authorized to receive or access data. Some cryptographic systems use a random or pseudorandom number as part of an authentication process. A pseudorandom number, which is produced by a pseudorandom number generator, is a number whose possible values may not have an equal chance of occurring, and may be predictable in that one pseudorandom number is useful in determining the value of a subsequent pseudorandom number. When used as part of an authentication process in a cryptographic system, a pseudorandom number should be as unpredictable as possible.
Entropy is a measure of unpredictability. To provide a high level of entropy, a pseudorandom number generator should generate pseudorandom numbers whose possible values have an equal chance of occurring, and past pseudorandom numbers should not be useful in predicting subsequent pseudorandom numbers. In other words, a pseudorandom number generated by a pseudorandom number generator should be indistinguishable from a random number produced by a random number generator. Because a pseudorandom number generator typically has its initial state established, or "seeded," by gathering truly random data from its physical environment, a pseudorandom number generator may be compromised if there is insufficient entropy in its initial state or "seed." However, the pseudorandom number generator may be influenced by ongoing operations, and thus may pick up additional truly random data from its environment as it continues to operate, thereby enhancing its unpredictability.
If a pseudorandom number used as part of an authentication process is not generated with a sufficient level of entropy, an unauthorized requester that gains access to the communication between, for example, a transmitter and a requester of data from the transmitter, may be able to become authenticated during an authentication process that uses the pseudorandom number. For example, using a pseudorandom number generated with insufficient entropy, an unauthorized computer system might be able to limit the possible values of subsequently generated pseudorandom numbers and predict a subsequently generated pseudorandom number. This would, in accordance with an example authentication protocol, enable the unauthorized computer system to impersonate the transmitter by sending the predicted pseudorandom number to the receiver. Because the predicted pseudorandom number has the value of a pseudorandom number that could have come from the transmitter, the receiver would send to the unauthorized computer system a response that would be valid if the pseudorandom number had come from the transmitter.
The unauthorized computer system could thus impersonate the receiver by sending to the transmitter the receiver's response to the predicted pseudorandom number. As a result, the unauthorized computer system would be authenticated as an authorized recipient of data from the transmitter. Thus, a pseudorandom number should be generated with a sufficient level of entropy such that the pseudorandom number cannot be used to determine the value of a subsequently generated pseudorandom number.

Method and apparatus for increasing the entropy of a pseudorandom number


Improved carrier materials for use in electrophotographic processes and processes for producing such carrier materials are disclosed. The carrier materials feature a preferably conductive core coated with an first conductive layer and a second, insulative layer. The coating layers preferably comprise a fluoropolymer matrix or other triboelectrically chargeable substance or substances. In one embodiment the same fluoropolymer is used in the first and second coatings.

The present invention relates to electrophotographic carrier particles, and particularly to carrier particles for electrophotographic developers which provide improved solid area development.
Electrophotographic processes and apparatus employ the use of toners, which typically comprise a resin and a colorant, along with other desirable additives like charge control agents. In general, a desired image is formed on an organic photoconductor (OPC) coated medium such as a drum or belt in the form of a charged pattern representing the image. Toner is electrically attracted to the charge on the drum and adheres to the drum in an imagewise manner. Lastly, the toner image is transferred from the OPC medium to an image-receiving substrate (typically paper) and fused, resulting in permanent image formation on the substrate.
In magnetic brush development systems, charge is imparted to the toner triboelectrically by mixing toner particles with carrier particles, typically resin-coated steel particles about 20 to 200 .mu.m in diameter. The toner particles adhere to the oppositely-charged carrier particles and are conveyed from a hopper to the magnetic brush roller system. On the roller, chains of the toner-laden carrier particles form, and as the chains are conveyed on the roller into the gap between the roller and the OPC medium, the charged toner particles are attracted to and deposited on the oppositely-charged latent image areas of the OPC medium. The carrier particles are collected and recycled for remixing with toner.
Since the carrier is a recyclable component of the developer, it is desirable to make the carrier last as long as possible, to minimize cost of usage. After a period of mixing with toner, toner particles tend to irreversibly adhere to the carrier, rendering triboelectric charging ineffective and necessitating replacement of the carrier. This is a problem sometimes referred to as "toner scum", and is noted with fluoropolymer coating materials such as polytetrafluoroethylene (PTFE). However, these materials are triboelectrically desirable for use in making carrier; fluoropolymers typically have a low surface free energy due to the presence of carbon-to-fluorine bonds and, as such, make ideal materials for carrier coating. Toner filming or scum may be suppressed by incorporating certain silicones and copolymers of tetrafluoroethylene (TFE), p-vinylidene fluoride and the like. However, the lack of solubility in common organic solvents and lack of adhesion to ferromagnetic substrate materials effectively precludes their use with normal fluidic coating equipment and processes. The lack of adhesion problem has been addressed by the provision of another agent such as a heat-curable epoxy system to adhere the PTFE to the substrate, but this solution is less than desirable, since the presence of the epoxy alters the characteristics of the end-product carrier material.
Another problem in the art relates to solid area development and the control thereof. In carrier/toner systems, uniform application of toner, i.e., "toning," across relatively large area of the document is desired. This is commonly called "solid area fill." During formation of a latent image on the photoconductor surface, an electric field is formed of the size and shape of the optically projected image (i.e., "imagewise".) Electrostatic field lines of force tend to migrate to the edges of the latent image field, and toner, during development, follows these lines of force. If the shape of the field is not corrected, most toner will be deposited along the edges of the latent image field, resulting in little or no development of the interior of the image, a condition known as "hollow character defect" or "edging."
A generally applied solution to correct this defect is to move a conductive bar or the like into the field, whose force lines project into space. This has the effect of making the field lines project perpendicularly to the photoconductor surface and to space themselves evenly across the large solid image field. This effect is commonly known as the "development electrode effect;" the conductive material is termed the "development electrode."
Ferromagnetic carriers used in magnetic brush development take the place of solid development electrodes; if they are sufficiently conductive, the carrier renders excellent solid area fill to large image areas. The conductivity of the carrier particle determines the strength of the development electrode effect.
Examples of carrier core materials used in the prior art range from extremely resistive flint glass (which is only able to develop solid areas not larger than ordinary type fonts); to powdered iron and steel, which develops excellent solid area fill, but is highly susceptible to either rusting in high moisture environments, or the formation of "scale" which interferes with carrier coating adhesion. These core materials must be passivated and cleaned, either chemically or by surface oxidation.
Synthetic ferrite core materials are not rendered useless by moisture, since they are formed from metal oxides. They are more resistive than iron and more conductive than glass beads. To improve their solid area image development, however, it is usually necessary to incorporate electroconductive particles in the coating to enhance the development electrode effect.
Improved solid area fill arises from using greater amounts of electroconductive particles, but in prior art systems, large amounts (e.g., 10-12% by weight of coating) of carbon are used, resulting in the coating becoming so conductive as to preclude sufficient charging of toner, as evidenced by higher "background" and excessively dirty machines, as well as low yield (number of copies/cartridge.) Accordingly, improved development systems addressing these issues have been desired.


A web browser and browser method permit the display of web pages and dynamic effects related to displayed objects to be selectively synchronized for a plurality of browsers. A location attribute can be used to identify a browser at which an action is initiated and specify one or more browsers to display the results of the initiated action.

The present invention relates to World-Wide Web (web) browsers and, more particularly, to a system for selectively synchronizing the display and manipulation of web pages and other objects by a plurality of web browsers.
The World Wide Web (the "web") is a system of Internet servers that supports hypertext and the hypermedia extension (collectively, "hypertext"). Hypertext is a database system that can be used to link software objects by including in an object a pointer to another object. Hypertext is used to link text, sounds, images, programs, and other software objects. The web is typically accessed with a web browser, a computer program that fetches and displays objects, including web documents or pages formatted with HTML (Hypertext Markup Language) or XML (eXtended Markup Language). Specially formatted text or icons (hyperlinks or links) in the web page are hypertext pointers to other objects. A user can cause the browser to display another object by selecting the appropriate link. In addition, a browser can display dynamic effects produced by manipulation of software objects (such as a change in text color) upon the occurrence of an event specified in the displayed page (for example, movement of a cursor). Web browsers also typically include search capabilities to facilitate locating web pages of interest to the user. While the web potentially links millions of individual users and millions of documents, historically the model of the web has been that of the individual user searching out and displaying documents of interest to that user.
Synchronization technology has been developed to facilitate collaborative use of the web by groups of users. Page and object synchronization permits a plurality of web browsers engaged in a synchronized session to simultaneously display the same web page and the results of an action manipulating a displayed object. Synchronized page display and interaction with objects are bases of web conferencing services and are potentially valuable tools for e-commerce. For example, a buyer and a seller can simultaneously view the same product specifications or other commercial documentation.
While page and object synchronization facilitates global display of web pages and other objects, there are circumstances where it is desirable that certain actions be limited to a subset of users in the session. For example, during an e-commerce session a sales agent may wish to refer to a proprietary price list without disclosing the document to the potential purchaser. However, if the price list is opened on the agent's page-synchronized browser it will be displayed on the synchronized display of the purchaser's browser. On the other hand, the agent may wish to open an explanatory document in a window or frame for viewing by the purchaser. However, page synchronization does not support the use of frames. If one member of a session selects a hyperlink to load a new page into a frame displayed by a first web browser, the page will not necessarily be loaded in the proper frame on the remaining browsers of the session.
Likewise, object synchronization permits one user to cause an action manipulating a displayed object to be replicated on the browsers of the other users in the synchronized session. For example, a script language can be used to specify the occurrence of an action (such as, a change in text color) upon the happening of an event (such as, a mouse click) associated with an object (a section of text). When a first web browser of the synchronized session detects the event, it signals the other browsers of the session to display the same action as if the local user has instigated the event. However, it may be desirable that the action be initiated or displayed on a limited set of browsers of the session. For example, the sales agent may wish to display a message on a customer's remote display in response to a mouse click on the agent's local display without displaying the message locally.
What is desired, therefore, is a system to control object and page synchronization permitting user inputs at selected browsers engaged in a synchronized session to manipulate and display pages and other objects on a subset of the browsers of the session.

Selective synchronization of web browsers


A resin composition for semiconductor encapsulation contains an epoxy resin (A); a phenolic compound (B) containing two or more phenolic hydroxyl groups; an inorganic filler (C); and a curing accelerator (D). The epoxy resin (A) contains an epoxy resin (a1) represented by the formula (1) wherein Ar is a C6-C20 aryl group, R1 is a C1-C6 hydrocarbon group, R2 is a C1-C4 hydrocarbon group, W1 is oxygen or sulfur, RO is a C1-C6 hydrocarbon group, a=0-10, g=0-3, 0<m<1, 0<n<1, m+n=1 and m:n=1:10 to 1:1, and the resin composition has a moisture absorption rate of 0.22 weight % or less when the composition is humidified at 85° C. and 85% R.H. for 168 hours:

1. Technical Field
The present invention relates to resin compositions for semiconductor encapsulation and semiconductor devices.
2. Related Art
Recent trends towards higher density and higher integration in electronic components and semiconductor devices, such as integrated circuits (ICs), large scale integrated circuits (LSIs), and very-large-scale integrated circuits (VLSIs) stimulate conversion of packaging from insertion mounting to surface mounting. Such trends require lead frames with an increased number of pins and leads with narrower intervals. Surface mount quad flat packages (QFPs), which are compact and lightweight, are used for a variety of semiconductor devices. These semiconductor devices are generally encapsulated with epoxy resin compositions, which have high compatibility among high productivity rates, low material costs, and high reliability.
Since these epoxy resin compositions for semiconductor encapsulation must be nonflammable, brominated epoxy resins, such as tetrabromobisphenol A epoxy resins and brominated phenol novolak epoxy resins, and antimony oxide, as flame retardants, are compounded to main components.
In recent years, however, use of halogenated compounds, which involve the risk of generation of dioxin analogs, and highly toxic antimony compounds has been regulated for the purpose of environmental protection. In resin compositions for semiconductor encapsulation, technology on fire retardancy that does not use halogenated compounds, such as brominated epoxy resins, and antimony oxide has been studied. When semiconductor devices are preserved at high temperatures of 150 to 200° C. for long hours, bromine atoms and antimony compounds in the flame retardants cause an increase in resistance of the semiconductor devices and disconnection of gold wires. From this viewpoint, epoxy resin compositions for semiconductor encapsulation not containing bromine flame retardants or antimony compounds are required. Metal oxide flame retardants, such as aluminum hydroxide and magnesium hydroxide, have been used instead of bromine flame retardants or antimony compounds. Unfortunately, these metal oxide flame retardants lead to an increase in viscosity of melt resins and a decrease in soldering resistance of the composition.
Japanese Unexamined Patent Application Publication Nos. 2004-203911 and 2004-155841 disclose epoxy resin compositions for semiconductor encapsulation containing epoxy resins having biphenyl aralkyl skeletons. Although these epoxy resin compositions do not contain flame retardants, they exhibit high flame retardancy. Furthermore, these epoxy resin compositions have advantages of low moisture absorption, low modulus when being heated, high adhesiveness, resulting in production of highly reliable semiconductor devices. A disadvantage of these resins, however, is high production costs.
An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation which does not contain a brominated flame retardant or an antimony compound, exhibit high flame resistance, and high soldering resistance after humidified, and has an advantage of low material and production costs.
Another object of the present invention is to provide a semiconductor device encapsulated by the cured resin composition.

Semiconductor encapsulant of epoxy resin, polyphenolic compound, filler and accelerator


A seatbelt height adjuster includes a track, a slider slidably coupled to the track, slots in one of the track and the slider and teeth on the other of the track and the slider. The teeth are selectively engageable with the slots. The seatbelt height adjuster includes a D-ring supported by the slider and leaf springs disposed on opposite sides of the slider. The leaf springs are each engaged with the track and biasing the slider in opposite directions.

Vehicles include seatbelts for each of the seats. The seatbelt includes webbing that, when the seatbelt is buckled, extends across an occupant of the seat. An anchor attaches one end of the webbing to a vehicle body. The other end of the webbing feeds into a retractor, which includes a spool that pays out and retracts the webbing. A clip slides freely along the webbing and, when engaged with a buckle, divides the webbing into a lap band and a shoulder band. A D-ring is mounted to the pillar of the vehicle and supports the seat belt at shoulder level of the occupant. The D-ring may be vertically adjustable along the pillar to accommodate varying shoulder heights of different occupants. For example, the D-ring may be manually adjustable.


A multifunctional fluid level and quality sensing device including a fluid level sensor and a capacitive sensor for detecting fluid level, fluid quality, errors in the sensing device, and issues in a fluid delivery system. In detecting fluid level, impedance of the capacitive sensor is used in improving sensing performance of the fluid level sensor, while in detecting fluid quality and errors in the sensing device, an expected impedance range with an upper boundary value and a lower boundary value is calculated, and a fault is generated when the measured impedance value is out of the expected impedance range. The fluid level and quality sensing device can also be used in a fluid delivery system for detecting system issues, and the results can be used for further isolating errors in the system. Operating status of higher level system provides more information for this purpose.

In some applications, e.g. in a fueling system of an engine, or a DEF (Diesel Exhaust Fluid) delivery system of a SCR (Selective Catalytic Reduction) apparatus, fluid level needs to be maintained above a certain level, and fluid quality issues, such as impure fluid or diluted fluid, need to be detected for avoiding deterioration in system performance and damages to the system. In these applications, normally a fluid level sensor and a fluid quality sensor are used for measuring fluid level and monitoring fluid quality.
Fluid level sensors can be either mechanical fluid level sensors or non-contact sensors. A commonly used mechanical fluid level sensor is a reed switch sensor which has magnetic reed switches activated by a force created with a magnetic float, while an ultrasound fluid level sensor is a non-contact sensor measuring fluid level using an elapsed time starting from the transmission of an ultrasonic sound wave to the reception of an echo.
A variety of sensors can be used in monitoring fluid properties. For example, a conductivity sensor can be used to measure the impedance or conductivity of a fluid, and a tuning fork sensor is able to detect changes in fluid density. However these sensors normally are point sensors, i.e., only fluid properties in a local area can be measured. As a result, it is difficult to detect a simple tampering to a fluid, e.g., disposing the sensor into a jar filled with a normal fluid and delivering a different fluid instead.
In the fluid level and fluid quality sensing, sometimes the rationality of the sensors needs also to be monitored to avoid false detections. Rationality errors of a sensor are in-range errors with which a sensing value obtained from the sensor is still within a normal sensing range, however, it is out of an error tolerance. Normally indirect methods are used in monitoring the rationality. For example, in a DEF delivery system of a SCR apparatus, a change in fluid level can be calculated using the amount of DEF being released if there is no refill or drain. Thereby, rationality of the fluid level sensor can be examined by comparing the calculated fluid level value to the sensing value. In the SCR apparatus, quality issues can be detected by using the deNOx efficiency of the apparatus, i.e., when a low deNOx efficiency is detected, a possible cause is diluted DEF. And these fluid quality issues can be further compared to the results obtained from the fluid quality sensor to verify its rationality. However, in the indirect methods, a few factors may significantly affect the diagnosis. For example, in the diagnostic methods mentioned above, slosh in DEF fluid and dosing accuracy may significantly affect the diagnosis of the fluid level sensor rationality, and the fluid quality sensor rationality is subject to the effects of DEF dosing accuracy, NOx sensor accuracy, and control algorithms used in the SCR apparatus. These effects may cause a false passing or a false alarm.
For overcoming the problems associated with the fluid quality sensing and sensor rationality diagnosis, it is then an objective of the present invention to provide a multifunctional sensing device that is able to detect both of quality level and fluid quality in a bulk fluid. The detection of fluid quality in the bulk fluid makes it difficult to tamper the fluid. A further objective of the present invention is to provide a sensing device that not only can detect fluid level and fluid quality, but is also able to detect rationality issues in the sensing device itself. Yet another objective of the present invention is to provide a fluid level and quality sensing device that is able to detect failures in a fluid delivery system in which the fluid level and quality sensing device is positioned. Yet another objective of the present invention is to provide a diagnostic method that is able to isolate issues in fluid quality, sensors, and the fluid delivery system.

Multifunctional fluid level and quality sensing device


Manual braking system with a variable braking force for a wheelchair. Caliper type brakes positioned to mount on and exert braking force on disks mounted to interior “disk” hubs rotatably mounted to the wheelchair frame wheel hubs are mated with the “disk” hubs with a push button release pin allowing the wheel to be quickly removed without disturbing disk braking system. Caliper brakes are actuated by a manual lever arm, cable and pulley combination mounted to the frame of the wheelchair. The lever is provided with and without a plunger mechanism. A plunger mechanism allows the user to maintain the manual braking force exerted on lever without hands. The plunger mechanism is fixably mounted and positioned to insert a plunger head into notches on the lever. The force exerted by the plunger head is sufficient to hold the plunger head within the notch and prevent movement of the lever without manual force.

1. Field of the Invention
The present invention relates generally to the field of wheelchairs and, more specifically, to a manual braking system with a variable braking force and quick release, detachable wheels for manual wheelchairs.
2. Description of the Related Prior Arts
Numerous types of braking mechanisms for manual wheelchairs are known in the art. The most typical manual wheelchair brake is a manual "over center" locking device which is activated by a lever arm and, when forced into its locking position, presses a braking member against the surface of the wheelchair tire creating a frictional braking action. Several factors mitigate against the usefulness and reliability of these types of brakes. Loss of tire pressure reduces the frictional force exerted by the crossbar on the tire and hence reduces the braking effect. A significant air pressure loss leaves these brakes useless. During transfer in and out of the chair, this type of brake allows the tire to slide underneath the crossbar and the wheelchair to move. Similarly, the brakes are ineffective and will not adequately hold the wheelchair on an incline. Other types of manual brakes include caliper type brakes manually activated with a lever arm mounted to a cable and brake assembly causing brake pads to press against the rim of the wheelchair wheel. Typically, braking mechanisms for wheelchairs only apply a braking force to one wheel. If an equal braking force is desired on both wheels, the user is required to perform the difficult task of using both arms at the same time. Finally, these types of manual brakes, whether caliper type brake or not, do not allow for a variable braking force to be exerted on the tire or rim. A variable braking force allows the user to both slow the wheelchair and ultimately stop it and hold it in place when desired.
Patents to Ross and Gunther, U.S. Pat. No. 5,358,266 and Lautzenhiber, U.S. Pat. No. 4,805,711 describe a braking member, which applies a braking frictional force directly to the wheelchair tire which is manually activated by a lever arm. There are also disclosed in the art several manual braking mechanisms which utilize a cable actuated caliper braking mechanism on the rim of one wheel or on the rims of both wheels with two distinct braking systems operating separately. Examples of these types of braking mechanisms are disclosed in patents to Herron, U.S. Pat. No. 4,560,181; Kawecki, U.S. Pat. No. 4,204,588; and Lemarie, U.S. Pat. No. 4,538,826. Finally, a patent to Berry, U.S. Pat. No. 5,492,355 discloses a caliper type braking mechanisms that discloses caliper type brakes which operate on the tire rim of each wheelchair wheel and can be activated by the use on one lever. Many of the same deficiencies discussed above apply to each of these braking mechanisms.
Wheelchair users have reason to frequently remove the wheels from their wheelchairs. It is often done for storage purposes, for brake adjustment, for wheel repair, and for wheel exchange. For example, in order to store a wheelchair in a vehicle, it is often desirable to remove the wheels.
Heretofore, the wheels on manual wheelchairs and other types of wheelchairs have been attached to the wheelchair frame by some type of hub with the wheels secured to the hub with nuts and bolts. In order to remove the wheels from the wheelchair, it has been necessary to unscrew and remove each of the nuts and bolts securing the wheel to the hub. This is a time consuming and cumbersome process. Once again, wheelchair users who have arm or hand limitations may not be physically able to remove the nuts and bolts.
More recently, it has become common in the art to attach wheels to manual wheelchairs using quick release locking pins which hold the wheel to the axle. In this type of design, it is difficult to also have a braking means on the wheelchair wheel other than the manual "over center" locking device which presses a braking member against the surface of the tire as described herein. Heretofore, other braking systems such as those which utilize caliper type brakes operating on the rim of the wheelchair wheel, have been ineffective on wheelchairs with quick release locking pins because the braking means had to be released and moved or disassembled in order to remove the wheel and thereby defeating the purpose of the quick release locking pin.
It is desirable to have a wheelchair with an effective easily operatable manual braking mechanism and, at the same time having quick release detachable wheels.

Manual brake for a wheelchair with a variable braking force


A stacked electrical card connector assembly comprises an upper electrical connector (1) having a row of first tail portions (121), a lower electrical connector (2) stacked with the upper electrical connector (1) and having a row of second tail portions (221) having bigger width than the row of the first tail portions (121), a locator (51) assembled to a bottom surface of a rear end of the lower electrical connector (2) and receiving the first and second tail portions (121, 221), and a socket (52) adapted to be mounted on a printed circuit board and provided with a first and second terminals (521, 522) for electrically connecting with corresponding the first and second tail portions (121, 221) when the locator (51) is inserted into the socket (52).

1. Field of the Invention
The present invention generally relates to an electrical card connector assembly, more particularly to an improved electrical card connector assembly for connecting two different electronic cards to a printed circuit board (PCB).
2. Description of Related Art
With the tendency of reducing the size of a computer device, demand has arisen for increasing its data storage capacity at low cost. Generally, electrical cards, such as memory cards, are data storage devices which are electrically connected to the computer device. The electrical cards are portable instruments that are readily inserted into and extracted from electrical connectors of the computer device. The connectors typically have sockets to receive the electrical cards therein and headers connected to the computer device such that data can be transferred therebetween.
Due to the ever-increasing demand in today's Notebook Personal Computer (Notebook-PC) for high-capacity signal transmission, more electrical card connectors of the same kind or different kinds are arranged in "dual port" or stacked configurations. As disclosed in China Pat. issue No. 2662470Y, an electrical card connector comprises an insulative housing defining a recess in an insulative header thereof and a transition device retained in the recess. The insulative housing further defines a first receiving room and a second receiving room for receiving two different electronic cards. The transition device has a plug protruding downwardly from a bottom surface thereof, and the plug provides a plurality of first terminals and a plurality of second terminals extending downwardly at opposite longitudinal sides thereof. The electrical card connector further has a plurality of first and second electrical contacts with free ends extending into the first and second receiving room for engaging with the electronic cards and opposite ends soldered on the transition device and connecting with the first and second terminals of the plug. As a result, when the two different electronic cards are inserted into the first and second receiving rooms, the electronic cards are connected to the first and second terminals of the plug. Furthermore, when the plug is inserted to a socket soldered on a printed circuit board (PCB), the electronic cards are finally connected to the PCB.
However, the signal transmission from the electronic cards to the PCB by the electrical card connector is complex and not good for the signal is through three retransmitting. Moreover, the configuration of the transition device is complex thereby increasing the manufacturing cost.
Therefore, the present invention is directed to solving the above problems by providing an improved stacked electrical card connector assembly which can improve the quality of the transmission and further reduces the cost.

Stacked electrical card connector assembly


According to one embodiment, an electronic apparatus includes a first avalanche photo diode, a second avalanche photo diode, a first pulse circuit, a second pulse circuit, a first waveform shaping circuit, a second waveform shaping circuit and an adder. The first pulse circuit is configured to shape a signal of the first avalanche photo diode to a first pulse. The second pulse circuit is configured to shape a signal of the second avalanche photo diode to a second pulse. The first waveform shaping circuit is configured to shape the first pulse to a third pulse having a narrower frequency bandwidth than that of the first pulse. The second waveform shaping circuit is configured to shape the second pulse to a fourth pulse having a narrower frequency bandwidth than that of the second pulse. The adder is configured to add the third pulse and the fourth pulse.

It is possible to detect photons with high sensitivity by using avalanche photo diodes (APDs) operating in Geiger mode. However, if various operations including distance measurement are executed using APD arrays, signal processing is required by the circuits in the next stage. For example, signal processing can be used to make photon counting easier. However, the processed signals may include harmonic components.
Since APDs with shorter dead times are available today, the demand for developing high-speed circuits connected to the output terminals of APDs is becoming greater. The development of technology which enables highly accurate distance measurements without the use of expensive high frequency circuits is needed. One example of the high frequency circuits are circuits capable of transmitting and processing signals with wide frequency bandwidths including harmonic components.

Electronic apparatus and measuring method of detecting pulses depending on photons comprising dual waveform shaping circuits


An exhaust muffler for mounting on the transom of a powerboat in association with the exhaust pipes which extend through the transom. The muffler comprises a housing extending laterally across the stern of the boat and rearwardly from the transom to define an interior space. The housing has a floor located below the water line; opposed end walls; a front wall located adjacent to the transom with openings formed therein, through which exhaust gas can pass from the exhaust pipes; a rear wall having exhaust ports formed therein and a cover that encloses the interior space. Located within the enclosed space are muffler inserts secured to the floor and also to the front and rear walls. Each insert has a domed portion defining a muffling chamber that communicates with the respective exhaust pipe, and a second domed chamber defining an expansion chamber that communicates with the respective exhaust port located in the rear wall of the housing. The muffling chamber and the expansion chamber are in communication with one another through a passage located below the water line and defined by a portion of the insert and by the floor of the muffling chamber. Accordingly, exhaust gas introduced into the muffling chamber is forced through the water filled passage into the expansion chamber and then exits through the respective exhaust port.

This invention relates to an exhaust muffler for use on marine engines of the type found on inboard/outboard power boats, and specifically to an outboard exhaust muffler which is located outside the hull and aft of the transom.
Inboard/outboard type power boats typically have a plurality of exhaust pipes extending through the transom at the stern of the boat. These exhaust pipes are typically located slightly above the waterline. With larger marine engines, the exhaust noise emanating from the exhaust pipes can be substantial. Such exhaust noise is often disturbing to occupants of the power boat, to water skiers who are the following the boat, to other boaters and to nearby residents.
Many communities have established anti-noise ordinances which prohibit power boats producing levels of noise above certain decibel limits, particularly in connection with waterways that extend through residential communities. For these reasons and others, it is desirable to provide a muffler at the stern of the power boat to reduce the noise of engine exhaust.
Typical examples of prior art power boat mufflers intended for this purpose are shown in U.S. Pat. Nos. 4,744,778 and U.S. Pat. No. 4,786,265. These devices provide a combination swim platform and muffling device mounted at the stern of the boat. They generally include one or more vertical baffles extending down into the water that partially fills a muffling chamber. With this system, the pressure of the exhaust gases forces the gas below the water level and through to the other side of the baffle to another chamber from which the exhaust gas is discharged, usually through an exhaust outlet with an integral flapper valve.
The marine engine exhaust muffler of the present invention provides an improved construction over that described above and affords other features and advantages heretofore not obtainable.