A method for coding data packets (DP) having at least one control command (S) and one data byte (B). The data packets are divided into sequences of control and/or data time blocks (SB, DB) each having a predetermined number (M) of time segments (ZS), whereby these can assume an on-value or off-value (EW, AW). At least one control command is coded in the time segments of a control time block, and a data byte is coded in the time segments of two data time blocks, whereby an on-value follows each time segment with an off-value. The method can be advantageously used in identification systems (IS) in mobile data carriers (DT) and in write/read devices (SL). The method results in the provision of a higher data transfer rate for transmitting data packets.

The invention relates to a method for coding data packets that include at least one control command and at least one data byte.
Contactless identification systems operate on the basis of contactless transmission technologies. These may be based on an electromagnetic method, e.g. using light or infrared, or on ultrasound, etc. Systems of this type are used, for example, to identify persons, or moving goods or means of transport. To this end, the necessary data are transmitted from a transceiver device via a contactless data transmission path, e.g. via an air interface, to a data medium and back. The contactless identification system also permits the recording of data, e.g. while the data medium moves past, without the latter having to be inserted into or drawn through a read/write device. Data media of this type are used, for example, as travel tickets with an electronically reloadable credit, whereby the appropriate travel fare is automatically deducted when the means of transport is used.
So that the data media can be used for unlimited periods of time, the integration of chemical energy stores, e.g. batteries, is preferably dispensed with. The requisite electrical energy of the data media is therefore drawn in a contactless manner externally, i.e. from an energy source originating from the transceiver device, e.g. an electrical or magnetic field. Suitable transmission and coding methods are therefore required for communication between the transceiver device and data media of this type. On the one hand, only specific frequency bands are normally released for the transmission of data, e.g. the ISM frequency bands (Industrial, Scientific & Medical), for industrial, scientific and medical applications. Possible national radio regulations may define, inter alia, the modulation bandwidths and field strengths which must be maintained. On the other hand, the transmission and coding methods must also ensure the energy supply of the electronics on the data medium.
Such methods are known, e.g. according to the standard ISO/IEC 15693, Part 2, "Air Interface and Initialization". Methods of this type enable continuous energy supply of the data medium electronics, originating from the energy of the applied carrier frequency of the transceiver device. Here, the carrier frequency is de-activated for a maximum time interval only in order to modulate the data which are to be transmitted. Within this time interval, an energy store previously charged by the electrical or magnetic field must be able to bypass the energy supply of the data medium electronics. A resonant circuit or capacitor on the data medium, for example, can be used as a temporary energy store. Here, the data are coded by de-activating the carrier at defined positions within a cyclical time pattern. Taking into account the aforementioned maximum time interval, the standard furthermore defines the field strength limit values for the sidebands produced through modulation at a specific carrier frequency. The time ratio of the activated to the de-activated carrier frequency on the one hand determines the level of the sideband modulation. Furthermore, consecutive changeovers from the activated to the de-activated carrier frequency also contribute to a significant increase in the sideband modulation. The need to adhere to the sideband limits defined in the standard results in a maximum possible data rate. For an ISM frequency band according to standard 15693, Part 2, page 6, for example, this data rate is 26.48 kbit/s.
The disadvantage of the aforementioned method according to the standard ISO/IEC 15693, Part 2, is that the data rate which is possible for a frequency band is no longer adequate for many applications, or insufficient time is available to transmit the data.

Method for coding data packets for transmission over an air interface


An analogue to digital converter generating at least two threshold levels and a comparator for comparing each of the levels with the input signal and generating a primary digital output signal to provide an indication that the input signal has crossed one of the threshold levels. The converter comprises a timer for determining the elapsed period of time between the input signal crossing a first level and the input signal crossing a second level and for generating a secondary output signal representing the elapsed time, whereby the secondary digital output signal and the corresponding primary output signal are used to provide a digital representation of the analogue input signal. The converter may also comprise a receiver of the primary digital output signal from the comparator and for providing an UP/DOWN digital output signal to indicate in which direction the input signal crossed the threshold level.

1. Field of the Invention
The invention relates to a method and apparatus for converting an analogue input signal into a digital representation. In particular, the invention relates to an apparatus for providing a digital representation of an analogue signal having characteristics advantageous for waveform matching and prediction.
2. Discussion of Prior Art
Analogue to Digital Converters (ADCs) enable an analogue input signal to be converted into a digital representation of the input signal which preserves information contained in the input signal. In the simplest ADC form, the zero-crossing discriminator, the output changes from a logical naught to a logical one when the input voltage crosses a reference voltage of zero volts. The input signal is transformed into a hard-limited telegraph function [D. Middleton and J. H. Van Vleck, IEEE, 54, 1 (1966)]; a simple sequence of naughts and ones. The spectral information contained in the input signal is also contained in the telegraph function, subject to a scaling factor, because the spectral information in the output digital representation is principally carried in the time intervals between the zero-crossings.
More sophisticated ADCs comprise a number of threshold-crossing discriminators each with its own reference voltage, where adjacent reference voltages are spaced apart by a common amount. For example, the outputs of sixteen discriminators expressed as a binary code would indicate that the input voltage lay somewhere between two particular reference voltages. However, for any significant amount of noise at the input, the input signal cannot be considered static during the conversion processes, causing the output digital representation to change rapidly and be almost indeterminate. To overcome this problem the input signal is held constant using a xe2x80x9ctrack and holdxe2x80x9d circuit and the resulting unambiguous output digital representation during the xe2x80x9choldxe2x80x9d phase is latched into a register by sample pulses which occur at equally spaced intervals of time. At the same time, the output digital representation may be made more compact.
Analogue to digital conversion methods in which the input analogue signal is periodically sampled at a predetermined constant rate and each sampled value is converted into a corresponding digital representation are standard. To convert analogue signals having high frequency components, a higher sampling rate must be used, resulting in an increased amount of output digital information. Furthermore, the high sampling rate results in an increased amount of unnecessary digital information for sections of the analogue input which have a relatively low frequency. For analogue signals having both high and low frequency components, a low sampling rate is not appropriate as the high frequency components cannot then be correctly identified. Conventionally, the choice of regular sampling rate is subject to the well known xe2x80x9cNyquist sampling criterionxe2x80x9d.
Furthermore, constant sampling rate analogue to digital conversion techniques are not particularly suitable for waveform matching and time series recognition applications. By sampling an analogue input amplitude at a fixed rate, two similar signals evolving in two different timescales, such as a car engine running at two different speeds, will give rise to two different output digital representations. Even though the two signals originate from the same source, the two different output digital representations will not be recognised as such due to the different timescales with which the input signals evolve.
In time series recognition applications, the analysis of data in the time domain may be used to extract information from a single channel sensor. A time series may be used to construct a trajectory evolving through multi-dimensional phase space which evolves with time over the surface of a geometrical object. The comparison of one such geometrical object, in particular a standard one, with a measured one provides a comparison of the state of one physical system with another. U.S. Pat. No. 5,835,682 describes a Heuristic processor which computes a multi-dimensional, nonlinear, predictive model constrained to predict the next sample of the time series from which it was calculated. The input data to the Heuristic processor are digital representations of analogue source signals for which conventional uniform sampling rate ADCs are employed. However, the use of uniform sampling rate analogue to digital converters has the inherent problem of introducing inaccuracies in the comparison of the predicted to measured time series. This degrades the temporal dependence and therefore has limitations when used for time series recognition applications.
The foundations of a general theory for randomised signal processing are discussed by I. Bihnskis and A. Mikelsons in xe2x80x9cRandomised Signal Processingxe2x80x9d (1992, Prentice Hall) which exemplifies the problems and benefits associated with some methods for processing signals subjected to non uniform sampling in time. The theory of non-uniform sampling for the digital encoding of analogue sources has previously been proposed as a means for data compression [IEEE Transactions on Communications, Vol. COM-29, No.1, January 1981 pp.24-32]. In the scheme proposed in this paper, information about an analogue source signal is contained in a digital representation of the time intervals between the crossing of the input analogue signal and any of the number of fixed threshold levels and in the direction of the threshold level crossing (up or down). The scheme is disadvantageous in that the digital representation is not compact and represents the interval between threshold crossings as pairs of zeros output at a regular rate. The pairs of zeros are interspersed with a 2-digit binary code representing direction.
Another sampling technique for analogue to digital conversion is described in IEEE Transactions on Circuits and Systemsxe2x80x94II: Analogue and Digital Signal Processing, Vol. 43, No. 4, April 1996. In this case, the final aim of the technique is to generate samples of the input signal that are uniformly spaced in time. This is done by recording the time instants at which the signal crosses any of the predetermined, fixed, quantisation levels, together with the specific quantisation level information, thus forming an output sequence consisting of xe2x80x9camplitude-timexe2x80x9d ordered pairs. This forms a local reconstruction of the signal which is then re-sampled by interpolation to provide equal interval amplitude samples. Once again, a non-compact sequence of ordered pairs is used to represent the input signal.
U.S. Pat. No. 4,291,299 describes a non-uniform sampling analogue to digital converter for converting analogue signals with large, short-term amplitude excursions. Such signals typically occur on telephone lines affected by lightning strikes or from power system faults. The sampling is non-uniform in both time and amplitude. Before the signal is sampled, multiple predetermined, absolute voltage levels are set as threshold levels. The system samples an input analogue signal and, whenever the input signal or the difference signal between the analogue signal and its last preceding sample, crosses any of the multiple predetermined levels this is detected and a digital code representing the particular level crossed is output This digital code forms part of an output digital word which also comprises a timer circuit count representing the time which has elapsed since the preceding sample occurred
An alternative analogue to digital converter system is described by R. Greenhalgh (IBM Technical disclosure bulletin, Vol. 7, no. 9, February 1965 (1965-02)). This document describes a system in which threshold levels are set at Axc2x1(xcex94A/2), where A is an analogue representation of the digital value stored in a register. If the input signal crosses one of the thresholds the register is reset to the value of the threshold that has been crossed, and a digital signal is output from the system which contains a digital representation of the value stored in the register and a digital representation of the absolute time value of the clock. Alternatively, the direction of the change in amplitude, as indicated by the tick register, is recorded instead of the absolute voltage.
GB2179516 is concerned with sampling an analogue waveform at a frequency significantly greater than the Nyquist frequency. Simple averaging of such an oversampled waveform to produce a waveform at the required sampling rate increases the dynamic range of A-D conversion. However, the method of GB 2179516 increases the dynamic range further by describing the analogue waveform as a mathematical function, from which a digital representation can be output at a desired sampling rate.
It is an object of the present invention to provide a method and apparatus for converting an analogue input signal into a digital representation which overcomes the problems arising from the temporal dependence inherent in constant sampling rate analogue to digital converters. It is a further object of the invention to provide a technique and apparatus for analogue to digital conversion which provides an output digital representation in compact form from which the original input analogue signal can be substantially reconstructed.
For the purpose of this specification, the term xe2x80x98analogue to digital converterxe2x80x99 shall be taken to mean a device for converting an analogue signal into a digital representation by sampling the input signal at a substantially constant rate. The term xe2x80x98analogue to digital interval converterxe2x80x99 shall be taken to mean a device for converting an analogue signal into a digital representation by sampling the input signal at substantially equal changes in amplitude. The term xe2x80x98time seriesxe2x80x99 shall be taken to refer to a sequence of amplitude values generated as a result of sampling an analogue input signal converted with small uncertainties in amplitude, as in a conventional ADC. The term xe2x80x98time sequencexe2x80x99 shall be taken to refer to a sequence of time interval values generated as a result of sampling an analogue input signal converted with small uncertainties in time interval.
According to one aspect of the present invention, an analogue to digital converter for converting an analogue input signal into a digital representation includes;
generation means for generating at least two threshold levels for comparison with the analogue input signal,
comparison means for comparing each of the threshold levels with the input signal and for generating a primary digital output signal to provide an indication that the input signal has crossed one of the threshold levels,
timing means,
characterised in that,
the elapsed period of time between the input signal crossing a first threshold level and the input signal crossing a second threshold level at a later time is determined by the timing means and a secondary digital output signal representing the elapsed period of time is also generated by the timing means,
the secondary digital output signal and the corresponding primary digital output signal being used to provide a digital representation of the analogue input signal.
In a preferred embodiment, the converter also comprises means for receiving the primary digital output signal from the comparison means and for providing an UP/DOWN digital output signal to indicate in which direction, UP or DOWN, the input signal crossed the threshold level, whereby the secondary digital output signals and the associated UP/DOWN digital output signal constitute a digital representation of the analogue input signal.
This provides the advantage that the output from the converter is series of signed, time interval values i.e. a digital representation comprising a series a time interval values having an UP or DOWN (+ or xe2x88x92) sign attached. The output from the converter can therefore be made compact. This is particularly advantageous for input signals which vary slowly with time. Using a conventional analogue to digital converter, which samples at a constant rate, results in a large amount of output data as the low frequency portions of the input signal are oversampled The present invention alleviates this problem as the sampling rate is determined by the local rate of change of the input signal.
Conveniently, the digital representation may be expressed as a 2""s complement number for subsequent input to a computer.
In addition, the analogue to digital interval conversion techniques proposed in the prior art provide a non-compact data output. The present invention is advantageous in that the digital output signal is a compact sequence of time interval values having an UP or DOWN flag attached (+ or xe2x88x92) to indicate the direction of threshold level change for a given time interval.
The comparison means may comprise means for comparing each of the threshold levels with the input signal or, alternatively, means for comparing each of the threshold levels with a signal derived from the input signal.
In a further preferred embodiment, the generation means include adjustment means for adjusting the threshold levels relative to the input signal in response to a threshold level crossing. This provides the advantage that only two threshold levels need be used as they can be made to track the input signal as it evolves in time.
In one embodiment of the invention, the adjustment means may comprise means for adjusting the threshold levels themselves in response to a threshold level crossing.
In this embodiment, the comparison means may comprise two comparators, each receiving the input signal and a different one of two threshold levels, UPPER or LOWER, forming an amplitude window about the current input signal, whereby if the input signal crosses one of the threshold levels the corresponding comparator generates a primary digital output signal to a subsequent logic stage for generating the UP/DOWN digital output signal.
In addition, the generation means may comprise two digital to analogue, each for generating a different one of the two threshold levels, UPPER or LOWER, for input to the associated comparator, whereby the digital to analogue converters each receive a digital input determined by the direction of the UP/DOWN digital output signal generated by the preceding threshold level crossing.
The digital to analogue converters may receive the digital inputs via counter means which serve to increasingly or decreasingly adjust the threshold levels accordingly in response to the UP/DOWN digital output signal generated by the preceding threshold level crossing.
Alternatively, the digital to analogue converters may receive the digital inputs from a logic circuit which serves to increasingly or decreasingly adjust the threshold levels accordingly in response to the UP/DOWN digital output signal generated by the preceding threshold level crossing.
Preferably, following each threshold crossing, the threshold levels are substantially equal to VREF+xcex94V and VREFxe2x88x92xcex94V, where VREF is the value of the analogue input signal as the threshold level crossing occurs and xcex94V is a pre-set threshold voltage.
Alternatively, instead of adjusting the threshold levels themselves, the signal derived from the input signal may be adjusted in response to the derived signal crossing a threshold level.
For example, the converter may comprise,
sample and hold means for sampling the analogue input signal to provide a sample input value,
whereby the sample and hold means hold the sample input value until such time as the analogue input signal crosses one of the two, fixed threshold levels, +xcex94V or xe2x88x92xcex94V, at which time the sample input value is adjusted, thereby adjusting the threshold levels relative to the input signal.
In this embodiment, the converter may comprise;
a differential amplifier, receiving at one input the sample input value and receiving at the other input the evolving analogue input signal, the differential amplifier providing an output signal derived from the input signal, and
two comparators for comparing each of two, fixed threshold levels, +xcex94V, xe2x88x92xcex94V, with the derived signal and for providing the primary digital output signal to provide an indication that the derived signal, and therefore the input signal, has crossed a threshold level.
The converter may further comprise;
an absolute level crossing detection means, whereby the absolute-level crossing detection means provide an output each time the analogue input signal crosses the absolute level, and
means for adjusting the threshold levels relative to the analogue input signal in response to the absolute-level crossing detection output so as to correct for any cumulative errors in the threshold levels as required.
This provides the advantage that any cumulative errors in the adjusted threshold levels or in the adjusted value of the input signal can be corrected for.
In one embodiment, the threshold levels themselves may be adjusted in response to the absolute-level crossing detection output. Alternatively, the analogue input signal may be adjusted in response to the absolute-level crossing detection output. Typically, the absolute-level crossing detection means may be a zero-crossing detection means.
In an alternative embodiment of the invention, the converter may comprise a flash analogue to digital converter for generating a plurality of fixed, digital threshold levels and for converting the analogue input signal into a binary coded digital output, and wherein the comparison means comprise logic circuitry for comparing the current binary coded digital output with the previous binary coded digital output to determine whether and in which direction a threshold level crossing occurred. Typically, the logic circuitry compares at least the two least significant bits of the binary coded digital output with at least the two least significant bits of the previous binary coded digital output to determine whether and in which direction a threshold level crossing occurred.
The timing means may comprise a timer counter for measuring the elapsed period of time which occurs between threshold level crossings. The timer counter may comprise means for determining when the maximum count has occurred.
In any of the embodiments of the invention, the converter may also comprise means for initially normalising the analogue input signal such that any two or more analogue input signals input to the converter have a common amplitude scaling. This is particularly advantageous for waveform matching or time series recognition applications.
The converter may also comprise an anti-aliasing filter which serves to limit the fastest rate of change of the analogue input signal so that the time interval to which the fastest rate of change corresponds is greater than the time the converter takes to provide an output digital representation following a threshold level crossing.
According to a second aspect of the invention, a nonlinear system analyser for analysing an analogue input signal is characterised in that it comprises;
the analogue to digital converter as herein before described, for generating a digital representation of the input analogue signal,
processing means for receiving said digital representation and for generating a multi dimensional nonlinear predictive model, wherein the model is constrained such that it predicts the subsequent input signal.
The non linear system analyser may also comprise means for comparing the predicted sample input signal with the measured input signal.
According to third aspect of the invention, a method of converting an analogue input signal into a digital representation comprises the steps of;
(i) generating at least two threshold levels (UPPER, LOWER),
(ii) comparing the at least two threshold levels with the input signal,
(iii) generating a primary digital output signal to provide an indication that the input signal has crossed one of the threshold levels,
characterised in that it comprises the additional steps of,
determining the elapsed period of time between the input signal crossing a first threshold level and the input signal crossing a second threshold level at a later time,
producing a secondary digital output signal representing the elapsed period of time between the input signal crossing a first threshold level and the input signal crossing a second threshold level at a later time, and
providing a digital representation of the input signal from the secondary digital output signal and the corresponding primary digital output signal.
The method may comprise the further steps of;
providing a single UP/DOWN digital output signal from the primary digital output signal to indicate in which direction, UP or DOWN, the input signal crossed the threshold level, and
providing a digital representation of the input signal comprising the secondary digital output signals and the associated UP/DOWN digital output signal.
The method may further comprise the step of expressing the digital representation as a 2""s complement number. This provides the advantage that for subsequent computer processing.
The method may comprise the further step of adjusting the threshold levels relative to the input signal in response to a threshold level crossing.
The method may comprise the step of comparing the input signal with two threshold levels. In this case, the method may comprise the step of adjusting the threshold levels themselves in response to the input signal crossing a threshold level so as to adjust the threshold levels relative to the input signal.
Alternatively, a signal derived from the input signal may be compared with the threshold levels. In this case, the method may comprise the step of adjusting the derived signal in response to the derived signal crossing a threshold level so as to adjust the threshold levels relative to the derived signal.

Analogue to digital converter and method of analogue to digital conversion with non-uniform sampling


A passively coupled RFID receiver is disclosed. The apparatus according to embodiments of the invention can reduce the cost of the RFID reader while significantly improving the linearity of the reader's receiver. An example system for reading RFID tags includes an active mixer passively connected to an antenna port to convert an incoming signal to a baseband signal. The baseband signal passes through a receive path, which may include other elements, and is ultimately provided to a processor that decodes the baseband signal. In some embodiments a complete RFID system making use of the passively coupled receiver includes an RFID transmitter that sends an RF carrier signal to cause the RFID tag to produce the incoming signal. In some embodiments a TX-RX coupler is connected to the transmitter, the receiver, and the antenna port, wherein the active mixer is passively connected to the antenna port through a receive port.

Radio frequency identification (RFID) is used in a wide variety of logistics, supply chain, manufacturing, and other applications. For some RFID protocols the reader may modulate commands onto a radio frequency (RF) carrier signal and the RFID tags respond to the modulated commands. Often the tags use simple backscatter modulation, which requires the RFID reader to provide a carrier signal for the tags to reflect their data back to the reader.
Passive backscatter radio frequency identification (RFID) systems use the reader's transmit signal to power the tags. In most countries there are regulatory limits on how much RF power the reader can radiate. The maximum RF output power, together with the minimum activation power of the tag, determine the maximum path loss between the reader and tag. Beyond that maximum path loss the tag does not get enough RF power from the reader to operate. Given the regulatory limits on radiated transmit power and sensitivity limits of tags, the maximum read range of passive backscatter RFID tags in the ultra-high frequency (UHF) range is about 10 to 15 meters. Because of this limited read range, there are often many readers and antennas installed to provide the desired coverage. This can create a serious interference problem for readers, since the reader's receiver must simultaneously decode the very low power backscatter responses from the tags while also receiving the very high power interference from nearby readers. Because of this, linearity is important in RFID receiver design.
In addition to the reader's maximum radiated power and the tag's minimum activation power, the tag's radar cross section modulation depth determines how much modulated backscatter signal power is returned to the reader. These three parameters: transmitter power, tag sensitivity, and tag radar cross section modulation depth, determine the required sensitivity of the RFID reader's receiver.


Methods, apparatuses, systems, and software are disclosed for providing a phone or other audio communication device with a fixed-path acoustic echo cancellation feature that compensates for a fixed-path acoustic coupling caused by transmission of sound from one or more speakers to one or more microphones through, for instance, the phone body itself.

A traditional acoustic echo canceller (AEC) is often used in phones to at least partially cancel acoustic echo caused by coupling from a loudspeaker of the phone to a microphone of the phone. The acoustic signal from the loudspeaker can travel along many acoustic paths to the microphone, such as through the air via reflections off nearby objects, and through the body of the phone itself. While the acoustic path through the phone body is typically fixed, the environment around the phone may change at any time, and so the AEC is typically adaptive to continuously change its model of the total acoustic environment.
In some phones, especially low-cost phones, the acoustic isolation between the microphone and the loudspeaker in the phone body tends to be fairly poor. This creates a fixed acoustic path within the phone body from the loudspeaker to the microphone. Furthermore, the attenuation presented by this internal acoustic path tends to be much less than the corresponding attenuation associated with the external acoustic paths. As a result, the internal acoustic path may dominate the overall acoustic coupling characteristics between the loudspeaker and the microphone of the phone, as compared with the external acoustic environment.

Audio communication device and method using fixed echo cancellation filter coefficients


A composite insulator with a silicone rubber sheath coating the insulator rod between metal fittings. Adjacent the line fitting, at least, a series of weathersheds are mounted on the rod and fastened to the sheath with their hubs in abutting relationship and with one hub abutting the line fitting. Another series of sheds are spaced from each other and from the series of weathersheds having their hubs in abutting relationship.

Insulators for high voltage electrical transmission lines may take many forms. In recent years, composite insulators have become extremely popular. One such insulator comprises a rod fabricated of glass fiber impregnated with an organic binder. The rod is coated with a rubber insulating sheath and a plurality of rubber weathersheds are spaced along the rod and fastened to the sheath.
A composite insulator of this type normally has a high voltage electrode fitting fastened to the sheathed rod at one and a ground fitting fastened to the sheathed rod at the other end. Field experience has shown that the rubber sheath in the vicinity of the high voltage electrode end fitting can be susceptible to aging and/or erosion due to surface electrical discharges that can occur where extremely contaminated conditions exist.


A three-in-one apparatus for analyzing liquids, such as some body fluids, uses labeled molecular affinity binding, such as immunochromatography. The multi-functional diagnostic test device can detect an analyte, such as an antibody or antigen, which may indicate a particular condition. The multi-functional diagnostic test device provides multi-functional formats to apply in multiple different sampling methods, including the “dip”, “cassette” and “collection” formats. The diagnostic test device can accommodate a plurality of test strips, such as 18 test strips for analyzing up to 90 analytes.

1. Field of the Invention
One or more embodiments of the invention relate generally to apparatus for analyzing liquids, such as body fluids, using labeled molecular affinity binding, such as immuno-chromatography. More particularly, the invention relates to a multi-functional strip test apparatus for detecting an analyte, such as an antibody or antigen, which may indicate a particular condition.
2. Description of Prior Art and Related Information
The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
Labeled molecular affinity binding, such as immunochromatographic assays, have existed for decades and have proven to be an inexpensive way to screen for various conditions, such as abused drugs, and other conditions, such as pregnancy and cancer, or for single or multiple pathogenic conditions, such as HIV infection.
In the point-of-care test (POCT) setting, immunochromatographic assays are typically conducted using lateral flow strip technology as described in May et al., U.S. Pat. No. 5,656,503, incorporated herein by reference. With lateral flow devices, antibodies are movably supported on a solid support, such as a porous pad. Antigen derivatives are deposited as immobilized indicator lines downstream of the antibodies, whereby the target antigens in a fluid sample flow laterally as a liquid matrix by capillary action through the solid support. The antibodies are normally colored for visual indication. The fluid sample carries the antibodies downstream towards the indicator lines of immobilized antigen derivatives while a reaction takes place between the target antigens and the antibodies. Any antibodies that have not reacted with the antigen in the sample bind to the antigen derivatives at the indicator lines. When little or no target antigen is present in the sample, most or all of the colored antibodies are carried downstream to the indicator lines of the immobilized antigen derivatives. At the immobilized antigen derivatives, the colored antibodies bind together with the antigen derivatives in such concentrations that the colorant of the antibodies becomes readily visible. It is also known that the antigen derivatives' and the antibodies' roles can be interchanged. That is, the antigen derivatives can be labeled with colorant and movably placed in the solid support while the antibodies are placed as immobilized deposited indicator lines downstream.
Unfortunately, although they can be inexpensive and simple-to-use, depending on the type of condition being detected, these tests typically take from about 5 to 20 minutes to complete and provide a typical accuracy of between 75% and 95%, falling short of the 99% or above accuracy generally considered to be necessary for a confirmatory test. Moreover, these conventional tests provide no objective measure of a quantitative result, such as the concentration of a given drug present in the liquid being tested.
The reasons for the insufficient accuracy in many rapid in vitro diagnostic (IVD) test devices are primarily due to their current lack of overall higher sensitivity and specificity. Different samples may contain chemicals or particles which inhibit the rapid and well mixed liquid flow or otherwise interfere with one or both of the first and second affinity binding reactions.
Other prior devices have attempted to enhance sensitivity or specificity by pretreating various parts of the device with reaction or flow enhancing reagents, pH conditioning chemicals, or even non-specific adhesive blocking molecules which will "block-out" non-analyte molecules which might cause non-specific adhesion, or otherwise compete with the analyte in question for specific binding members, especially in the reaction zones region of the strip. These attempts have met with limited success in some types of testing, but do not provide the desired accuracy in many others. Also, pretreatment with two or more of the above pretreatments exacerbates the difficulties in obtaining uniform manufacturing due to potential incompatibilities between the pretreatment chemicals. For example, the pH conditioner might disrupt the effectiveness of the non-specific blocking member molecules. Moreover, the manufacturing step of pretreating with a second pretreatment chemical can dislodge some of the first pretreatment chemical.
Further, lot-to-lot variation in the manufacture of many IVD test devices can often lead to ambiguous results, such as false negatives as well as weak false positives, so-called "ghostlines" or "phantom lines". False negatives typically occur when non-specific molecules interfere with the first and/or second affinity binding actions. It has been found that non-analyte molecules can clump together in liquid samples that are not well mixed so that they temporarily prevent access between analytes and binding members. Even temporary interference in past devices can prevent an adequate number of labeled analyte complexes and/or ultimately immuno-sandwich complexes from forming. In this way, if a non-analyte molecule or clump of molecules blocks access between analytes and binding members for only a few seconds, it may be enough to induce a false negative result. Further, clumps of non-analyte molecules can carry an overabundance of the labeled mobilizable binding members to the second affinity binding site to generate a false positive result.
Depending on the particular test to be performed, the analyte to be detected, or the preference of the user, multiple test devices may be necessary for performing tests in different formats, such as a dip format, a cassette format or a collection format. Each of these test devices may include multiple parts, resulting in confusion, mismatched components, and the like.
Therefore, there is a need to improve the accuracy of rapid IVD test devices so that rapid, inexpensive, easily conducted and quantitative immunological testing becomes a reality and where a single device may be used for multiple test formats.

Multi-functional rapid diagnostic test device


A panel unit for roof drainage comprises plural panel sections with adjoining ones of the plural panel sections connected to be foldably collapsed on one another into a storage (e.g., transport) unit. In one embodiment, the panel sections are connected together for folding, e.g., by a hinge. Roofing saddles and roofing crickets of the present invention are formed using one or more sets of panel units. Sets of panel units are fabricated to have essentially the same footprint on the roof, although a lastly installed one of the sets of panel units is modified on site. A method of installing a roofing saddle comprised of the panel units is also provided.

1. Field of the Invention
The present invention pertains to method and apparatus for draining flat-roofed or low-slope roofed structures, and particularly to panels used for such purposes.
2. Related Art and Other Considerations
Since the beginning of "flat roof" building construction, it has been recognized that stagnant ponds of water are harmful. When water is left standing on any type of waterproof membrane, it accelerates the aging process of the membrane in that area. Accordingly, any place frequently covered by residual water left from a rain or snow melt will experience early failure.
Many schemes have been developed over the years to eliminate residual water ponds from what is now known as "low-slope roofing." For example, U.S. Pat. No. 4,014,145 to Groves teaches the art of using "roof saddles" to assist in eliminating standing water. As used herein, a roof saddle is a flat-bottomed pyramid which has an essentially elongated diamond-shaped bottom and a central peak or vertex on its top surface. Four surfaces of the saddle sloping down from the central vertex serve to allow water to run off the saddle for collection in drains provided in the roof. Drainage systems comprised of drain pipes and roof saddles have been the preferred method of eliminating residual water from essentially flat roofs for many years.
On very large roof expanses, building designers have often planned on the structural portion of the roof decks being built as a series of minor (low slope) pyramids to provide high centers and low valleys. A drain pipe was installed at each confluence of four valleys. Unfortunately, all too often the valley between two structural pyramids would become a pond for standing water. The typical solution usually is the utilization of roof saddles in the valleys to eliminate residual water.
Over the years, many methods have been employed to create and install roof saddles. Historically, the most frequently used method has been that of the roofing contractor forming saddles at the building site from low-cost fiber board or expanded polystyrene plastic foam. This on-site method is very slow and labor intensive.
As building construction contractors strive to finish their buildings faster in order to reduce costs, the "hand-made, on-the-job" method has become less favored. Rather, in order to reduce escalating labor costs, roofing contractors have increasingly turned to "pre-fabricated" saddles. Pre-fabricated saddles are custom made at a factory purportedly for speeding up the installation process.
Unfortunately, several problems arise utilizing the pre-fabricated method. For example, conventional "factory-made" roof saddles also turn out to be labor-intensive processes. Moreover, although factory labor tends to be lower in cost than construction labor, pre-fabricated roof saddle systems are also relatively expensive. In addition there is the problem of factory lead time. That is, a long lead time for factory orders (e.g., eight weeks) is inconsistent with the fast-track building approach employed by many building system managers. These managers desire to order and receive their material in just a few weeks. Therefore, transferring a labor-intensive process from the construction site to the factory does little to help the problem.
Ostensibly to reduce the labor costs inherent with pre-fabricated roof saddle systems, a method and apparatus for fabricating roofing saddles by computer-controlled machinery is taught in U.S. Pat. No. 5,663,882 to Douglas. While such computerized systems do reduce the cost of manufacturing pre-formed saddles, other problems are not addressed and some problems are spawned.
In computerized systems, the saddle components are built precisely to the length and width dimensions given in the architects' drawings. However, at the construction site, it is often necessary to make expedient changes. For example, for various reasons the roof configuration at the building site may not turn out to be strictly in accordance with the architectural drawings. For example, it frequently turns out that the drainage pipes have been moved in order to accommodate changes of the more important structural components of the building. In fact, in some cases the drainage pipes must be moved several feet in order to accommodate other newly added, or changed, building components. In such cases, the precisely manufactured conventional saddle diamonds are either too short or too long and thus will not form the drainage low-point at the drain pipe. Rather, a pre-fabricated saddle installed in an altered structure could either cover the drain pipe, or could instead form a low point several feet short of the drain. In either case, the precisely made conventional saddle is useless until extensive field cutting and repairs are made. Any cost or time saving otherwise attributable to a pre-fabricated conventional saddle is more than offset by having to modify such a precut saddle system when the saddle was made to architectural dimensions rather than actual building measurements.
Another problem with conventional pre-fabricated roofing saddles is the complexity (and thus cost) of the equipment required for computer controlled cutting and labeling. For conventional pre-fabricated saddles, an infinite variety of angles may be required. The requirement for widely varying angles contributes to the complexity of the saddle-fabricating machinery, and also to the frequency of repairs of such machinery.
Furthermore, saddles produced by conventional pre-fabricated saddle production systems have proved difficult to install, even when the actual structure matches the design drawings. In industry practice, the materials are shipped in a stretch-wrapped bundle approximating a four-foot cube. This package is comprised of many small pieces, as well as odd-shaped medium sized and large pieces. The smaller pieces are fragile and thus susceptible to being easily damaged. Also, as mentioned above, an infinite variety of angles are cut to accommodate any given roof shape. A system of labeling is required so that the installer can determine not only which pieces abut each other, but which edges of each piece must be joined. Many hours can be exhausted searching for the correct pieces to join, then matching the proper edges. If two packages are opened at the same time, the pieces can become intermixed, thus increasing the time spent to sort things out. If a breeze starts up, which is often the case on a rooftop, the smaller pieces can become lost. Thus, working with conventional pre-fabricated saddles transported in the plastic-wrapped cubes somewhat resembles solving an expensive jigsaw puzzle. Even with a complex labeling system, finding the correct pieces to join can become a challenge.
What is needed therefore, and an object of the present invention, is a roofing drainage panel unit which is inexpensive yet easy to fabricate, transport, and install.

Foldable roof panel unit and method of installation


A strain gauge (10, 40, 50), a pressure sensor (20, 60), and an interventional medical catheter. The strain gauge (10, 40, 50) comprises a substrate (11) and at least two sensitive gages (1, 2) provided on the substrate (11), the at least two sensitive gages (1, 2) being arranged along two mutually perpendicular directions and sharing one ground port (3). The pressure sensor (20, 60) comprises an elastomer (21, 61) and the strain gauge (10, 40, 50) provided on the elastomer (21, 61). The interventional medical catheter comprises a catheter distal end and the pressure sensor (20, 60) provided at the catheter distal end. The present application not only saves the trace space for mounting and using the strain gauge (10, 40, 50) on the interventional medical catheter, facilitating the successful mounting and use of the strain gauge (10, 40, 50) on the interventional medical catheter, improving the adaptability of the strain gauge (10, 40, 50), but also reduces the size of the strain gauge (10, 40, 50), thereby shortening the length of the elastomer (21, 61) of the pressure sensor (20, 60) and reducing the size of the interventional medical catheter.

For cardiac radiofrequency ablation catheters, strain gauges are generally provided thereon to measure the contact force between distal end of the catheter and the tissue or vessel wall, so as to accurately monitor the implementation process of the ablation treatment, thereby ensuring the successful rate of the operation. Due to the low price, fast response, large measuring range and stable performance, the strain gauge has been widely used in the interventional medical field.
Generally, the strain gauge is made by attaching a metal sensitive grid to a substrate of plastic film. The metal sensitive grid is a set of parallel wires formed by arranging a narrow conductor in a zigzag mode. When stretched, the sensitive grid becomes narrower or longer, and the resistance becomes larger. When compressed, the sensitive grid becomes thicker or shorter, and the resistance becomes smaller. Then, the strain gauge is disposed at the periphery of the elastic body. In this case, when the elastic body is deformed due to the electrode at the top of the elastic body that is subjected to a stress, the sensitive grid of the strain gauge on the elastic body is triggered to become longer or shorter, which in turn causes a corresponding change in resistance.
The resistance strain gauges commonly used on the market are strain gauges based on copper-nickel alloys that generally only have longitudinally arranged sensitive grids and a large circumferential surface area of the grid filament. Although the sensitivity coefficient can reach 2.0, the strain gauges based on copper-nickel alloys are significantly affected by the external temperature. Therefore, the strain gauge can only be used under conditions of dryness, no scouring and tight temperature control. However, for a cardiac radiofrequency ablation catheter, a temperature change of 25-75° C. is generated during the in vivo ablation, resulting in a temperature error of the measurement causes by the corresponding temperature change in the measured circumstance. Two main factors lead to the temperature error of the strain gauge. One is the temperature coefficient of the self-resistance of the sensitive grid and the other is the thermal expansion coefficients of the material of the strain gauge's substrate and the material of the testing material.
In addition, due to the large size of the existing strain gauge, the application of the strain gauge to the ablation catheter has been limited in a certain degree for that the strain gauges cannot be fitted with the ablation catheter in the axial direction.
Therefore, since the existing strain gauges have certain limitations, it is necessary to develop a strain gauge that has a small size, an easy installation on the interventional medical catheter, and a good performance in precision and sensitivity, as well as an insusceptible property by temperature.

Strain gauge, pressure sensor, and interventional medical catheter


An apparatus for collecting litter from the ground includes a frame adapted for movement along the ground, a hopper mounted at one end of the frame; and a collector assembly supported on the frame. The collector assembly includes a pair of rollers having a plurality of flexible fingers disposed radially on the periphery thereof, the rollers being substantially parallel to each other and disposed in a plane that is substantially parallel to the ground. The rollers are arranged so that the fingers on one of the pair of rollers intermesh with the fingers of the other of the pair of rollers so as to be able to lift litter between them. The apparatus further includes a device for conveying litter lifted by the pair of rollers to the hopper. The conveying device includes a plurality of fingers that intermesh with the fingers of one of the pair of rollers so as to remove the litter from the one roller, and a system for rotating the pair of rollers and the conveyor about axes that are substantially transverse to the direction of movement of the frame.

1. Field of the Invention
The present invention is directed to debris and litter collecting machines of the type that are generally intended to cover relatively large areas over which debris may be scattered, such as parks, beaches, highways, etc., and to retrieve the debris or litter that is commonly encountered in these areas.
2. Description of Related Art
Various litter collecting machines of this general type are disclosed, for example, in U.S. Pat. Nos. 2,916,753; 3,923,101; 3,993,141; 4,550,465 and 4,593,426. Litter retrieval machines of this type basically comprise a device for picking litter up from the ground, a storage bin or hopper for receiving the litter that has been picked up, and some form of means for transferring the litter from the collecting device to the storage bin.
A device substantially similar to that disclosed in abandoned U.S. patent application Ser. No. 06/606,583 has been sold in the United States more than one year prior to the filing of this application.
In some of these machines, the transfer of the collected litter from the collector to the storage bin involves a number of discrete handling steps in which the litter goes from one location to another between the ground and the storage bin. However, each time that a piece of litter must be handled by a separate piece of structure in the machine provides an instance in which the overall collecting efficiency of the machine can be reduced. For example, when a transfer of litter between two relatively moving machine elements is required, it is always possible that flexible types of litter such as cardboard cartons or paper wrappers can become jammed between the two elements and, rather than being transferred from one to the other, be returned to the ground or require stoppage of the machine to clear the obstruction. In another type of action, collected litter may be allowed to freely drop from one type of handling apparatus into another. For example, it may fall from a collecting roller into a trap area where it is picked up by a subsequent handling device. In such situations, it is entirely possible that litter such as glass bottles or the like may break as it falls into the trap area, allowing the smaller pieces to drop through spaces in the machine and return to the ground.
Some litter collecting machines, such as those disclosed in the previously noted '101 and '141 patents, employ a relatively simple collecting concept that does not involve numerous handling steps in transferring the litter from the collecting device to the storage bin. However, the basic collecting device itself is also simple in concept, comprising a series of relatively rigid rods mounted on a shaft and adapted to picking up certain types of litter or litter of certain sizes that is capable of being wedged between the rods.
A further disadvantage of litter collecting machines that utilize a plurality of flexible fingers to collect litter, such as those disclosed in U.S. Pat. Nos. 4,550,465 and 4,593,426, is that the fingers are subject to wear, thus reducing their effectiveness. The fingers in the prior art machines are difficult to replace.

Debris/litter collection apparatus having a conveyor which intermeshes with fingers of collector roller


Compositions, novel isolation sources and processes, and uses for unique policosanol containing compositions are disclosed. Seed and vegetable processing byproduct and/or “waste” streams are disclosed as containing policosanols with various relative amounts of the various long chain fatty/waxy alcohols. The policosanols are isolated and may be combined with other phytochemical/processing products, and are used in numerous food, beverage, health and/or nutraceutical applications.

1. Field of the Invention
The present invention relates, in general, to a method of obtaining policosanols from novel sources, and to compositions obtained by such method. The present invention also relate to a method of reducing cholesterol level in humans and animals. The present invention further relates to a composition comprising policosanols, with or without additional additives, in concentrations effective for cholesterol reduction.
2. Related Art
Currently, approximately 20% of the U.S. population has hyperlipidemia or elevated levels of serum cholesterol, which have been implicated as a leading cause of heart disease. More recently, in an effort to understand and alleviate the impact of coronary heart disease (CHD) on the modem world, the lipid profile has been examined more closely. A total cholesterol level is an obvious risk factor; however, a high level of the bulky low-density lipoproteins (LDL) in the blood stream is also cause for concern. These bulky macro proteins can easily get stuck in the intricate cardiovascular system, which leads to further blockage. Furthermore, a low level of the "cleaner" lipoproteins can be harmful as well. High-density lipoproteins (HDL) are compact, heavy macro proteins that move through the system with more precision and actually have beneficial effects as they sweep through arteries and knock loose stuck materials along the way.
Traditional strategies to reduce blood cholesterol levels have typically been to reduce or eliminate dietary intake of cholesterol. However, the normal diet of most western civilized individuals does not comply with these strategies. The health care profession has since put much emphasis on pharmaceutical tools to assist in lowering cholesterol. These statin drugs, or antihypercholesterolemic drugs, such as Lovastatin™, have proven effective; however, there is room for improvement. Statins are effective for only 50% of the people taking them and they cause side effects such as liver disease and muscle weakness.
Plant-derived long chain fatty or waxy alcohols (generically referred to herein as policosanols) have been demonstrated as having biological activity including lipid effects as well as ergogenic effects with benefits in cardiovascular, cerebral and muscular systems. Also, these compounds have activity as growth regulators for plants. 1-Triacontanol, or myricyl alcohol has been demonstrated as being a growth stimulant on a wide range of plants (U.S. Pat. No. 4,150,970). Recently, such compounds have been associated with inhibiting cholesterol biosynthesis and increasing LDL receptor-dependent processing (Menéendez, et al., Biol. Res. 27:199 (1994); Brit. J. Nutrition, 77:923 (1997)) with such effects being demonstrated in patients with type II hypercholesterolemia and dyslipidemia associated with non-insulin dependent diabetes mellitus (Mirkin, et al., Int. J. Clin. Pharm. Res. 21:31–41 (2001). Other applications that have been reported in the literature include platelet hyperaggregability, ischemia and thrombosis, prevention of drug-induced gastric ulcer and improvement of male sexual activity (WO 94/07830).
Free primary alcohols are found in many plant waxes; e.g., in leaf bark and stem waxes of most plants. Natural plant waxes may be grouped into waxes of palms, grasses and sedges, broad-leaf trees, and narrow-leaf trees (Albin H. Warth in The Chemistry and Technology of Waxes, 1956, Reinhold Publishing Corporation, NY. Pp. 76–341). The sugar cane, Saccharum officinarum L., of the grass family, order Graminenae, has an appreciable deposit of wax on the surface of the stalks. This wax is of considerable economic value as it is rich in long chain fatty alcohols.
Numerous patents and patent applications describe methods for the isolation and purification of long chain fatty alcohols (see, for example, JP 60-119514; JP 62-87537, U.S. Pat. No. 5,856,316 and WO 94/07830). Waxes from plant sources have been fractionated into different classes such as hydrocarbons, second alcohols, esters, ketones, aldehydes, free alcohols and acids. Usually, long chain free alcohols in plants are present either as free alcohols or as esters of these alcohols with acids. Such esters usually contain an even number of carbon atoms in the range C20–C54. The long chain free alcohols usually found are straight chain primary alcohols and mainly of an even length (C20–C36). Sugar cane wax, for example, may contain up to 26% free and esterified long chain alcohols while Carnauba wax may contain up to 52.5% free and esterified long chain alcohols (Hamilton, et al. Plant waxes in Topics in Lipid Chemistry, 3:199–269 (1972), F. D. Gunstone (ed.), John Wiley and Sons, Inc., NY).
It is well known in the literature that long chain aliphatic wax alcohols, referred to as policosanols, have anti-cholesterol effects. Gouni-Berthold et al. shows that doses of 10 to 20 mg per day of policosanol lowers total cholesterol (Gouni-Berthold, I. et al., Am. Heart J, 143:356–65 (2002)). U.S. Pat. No. 5,952,393 and U.S. Application No. 20010034338A1 disclose a purportedly synergistic anti-cholesterol effect of a composition comprising phytosterols and policosanols. U.S. Pat. No. 6,197,832 discloses the method of administering this composition of phytosterols and policosanols.
European Patent Application EP1 108 365 A2 discloses encapsulated policosanols for use in food applications.
U.S. Pat. No. 3,031,376 discloses the pharmaceutical use of certain long chain fatty alcohols in a method of increasing oxygen utilization.
European Patent Application EP1 108 363 A1 discloses processes for incorporation of long chain alcohols in edible oils.
European Patent Application EP1 108 364 A2 discloses a method for admixture of long chain alcohols in sterol compounds.
U.S. Pat. No. 6,277,403 discloses fat continuous emulsions containing, among other components, long chain alcohols having at least 20 carbon atoms in the alcohol chain.
U.S. Pat. No. 4,981,699 discloses a method for preparing an edible composition by extracting alcohols of 24–34 carbon atoms at subcritical or supercritical conditions and admixing peptides therewith.
U.S. Patent Application No. 2002/0016314A1 discloses compositions for reducing blood cholesterol and triglycerides comprising policosanol esters.
U.S. Pat. Nos. 5,865,316 and 5,663,156, and PCT Publication No. WO94/07830 disclose an extraction method of policosanols out of sugar cane wax and uses of those policosanol mixtures as a treatment for high cholesterol.
U.S. Pat. No. 6,328,998 discloses a method of treating high cholesterol with a pharmaceutically acceptable salt of L-carnitine and hexacosanol.
There are numerous other reports in the art for extraction of long chain alcohols from plant sources. For example, Staby and De Hertogh (Hortscience 74:411–412 (1972)) describe a process for separation of octacosanol in extracts from "Wedgwood" iris shots; Joshi and Singh report on the extraction of octosanol from Gmelina arborea (Heartwoods) (Z. Naturforsch, 25:693–694 (1970)); Piatak and Reimann describe isolation of octosanol from Euphorbia Corollata (Phytochemistry, 9:2585–2586 (1970)). Other sources of free primary alcohols in oils and waxes have included germs, kernels and other components of nuts, seeds, fruits and cereals (Kawanishi, et al., JAOCS 68:869–872 (1991)).
Methods in the art have been described for the purification of long chain free alcohols. These include crystallization, chromatographic separation (Hamiton, et al., Plant waxes in Topics in Lipid Chemistry, 3:199–269 (1972), F. D. Gunstone (ed.), John Wiley and Sons, Inc., NY.), gel permeation chromatography (WO 99/48853); multiple crystallization in different solvents (U.S. Pat. No. 6,225,354; EP 0654262).
Policosanols have been tested directly against statin drugs and they show similar or better total cholesterol reduction while policosanols improved HDL values, as well (Clinical reviews of Dalmer Laboratories).
Addition of policosanols or policosanols combined with other additives to foods will give the consumer who is concerned about lowering their cholesterol easier choices and more palatable options. For example, in 1999, the FDA approved a health claim of soy protein to reduce the risk of coronary heart disease. Studies showed that 25 grams of soy protein (or more) added to a daily diet had a cholesterol lowering effect. However, it has been noted that it is hard for the average consumer to consume 25 grams of soy protein. One object of the present invention would be to add policosanols to food already containing soy protein. The anticholesterol effect of the policosanols combined with the same effects of soy protein would be additive and the consumer would therefore have to consume less soy protein a day to reduce their risk of coronary heart disease. Also, since it is not known specifically how soy protein reduces cholesterol, there is a possibility policosanols and the soy protein would not only have an additive effect, but a synergistic effect as well.

Policosanol compositions, extraction from novel sources, and uses thereof


A sensor supervision system for periodically providing a test to accesses the status of a gas detection sensor, such as a carbon monoxide (CO) sensor, is provided. To access the status of the CO sensor, a processor provides a voltage to the sensor supervision system, such that a voltage is applied to CO sensor, charging the CO sensor. The status of the CO sensor is accessed by determining the change in the voltage charge of the CO sensor between two sampling time points. If the first sample voltage is substantially equal to the second sample voltage, i.e., a substantially constant voltage, the carbon monoxide sensor fails the test. However, if there is an change is the voltage change between the first and second sampled time points, the CO sensor passes the test.

Devices for detecting and generating a warning with respect to dangerous conditions, such as the presence of carbon monoxide (CO), are known. For example, various devices and systems are described in U.S. Pat. Nos. 5,517,182 to Yasunaga, issued on May, 14, 1996; 5,694,118 to Park et al., issued Dec. 2, 1997, 5,886,639 to Tanguay, issued Mar. 23, 1999, and 6,819,256 to Johnston et al., issued Nov. 16, 2004, the contents of all which are expressly incorporated by reference in their entirety.
In general, CO detectors employ one of three types of detectors: semiconductor, biomimetic and electrochemical."
Semiconductor CO sensors typically employ a thin layer of metal, such as tin dioxide, maintained at a relatively high temperature (e.g., 100.degree. C. to 400.degree. C.). The surface conductivity of the metal varies generally proportionally in accordance with exposure to ambient CO concentration. The semiconductor chip measures the migration of oxygen molecules through the surface of the sensor material.
Biomimetic sensors utilize a transparent substrate disk coated with a synthetic hemoglobin that mimics the reaction of natural hemoglobin in the presence of carbon monoxide. The biomimetic material darkens with cumulative absorption of CO. A light emitting diode (LED) transmits light through the biomimetic material to a photosensitive device. When the material becomes sufficiently dark to prevent adequate light from reaching the photosensitive device, the detector sounds an alarm.
Electrochemical sensors, in general, employ a chemical reaction to convert CO to carbon dioxide (CO2) to create a chemical imbalance in a portion of the cell which in turn generates a current indicative of the amount of CO present. Some electrochemical sensors utilize two chambers (one for CO and one for hydrogen).

Electrochemical carbon monoxide sensor supervision


An apparatus and method for delivering an additive-enhanced slurry for use in making gypsum wallboard, and configured for connection to a centrifugal mixer with a tangential discharge outlet, includes a conduit having a main inlet in slurry receiving communication with the mixer outlet and extending to a discharge spout for discharging the slurry proximate a wallboard forming area. At least one volume restrictor is associated with the conduit for creating back pressure between the volume restrictor and the outlet for keeping the mixer fill, and at least one pressure reducer associated with the discharge spout and configured for reducing the pressure of the slurry dispensed from the discharge spout. The apparatus is configured for maintaining a generally laminar flow from the mixer outlet to the discharge spout.

The present invention relates to a method and apparatus for preparing gypsum products (i.e., products comprising calcium sulfate dihydrate) from starting materials comprising calcined gypsum (i.e., calcium sulfate hemihydrate or anhydrite) and water. More particularly, the present invention relates to an improved apparatus for use in conjunction with the slurry mixer typically used in supplying agitated gypsum slurry to a wallboard production line. The basic technology of gypsum wallboard manufacture is disclosed in U.S. Pat. Nos. 1,500,452; 2,207,339; and 4,009,062 all of which are incorporated by reference herein. The present apparatus provides an improved mixing chamber which enhances the uniform mixing of foam into the gypsum slurry.
It is well known to produce gypsum products by uniformly dispersing calcined gypsum in water to form a slurry and then casting the slurry into a desired shaped mold or onto a surface and allowing the slurry to set to form hardened gypsum by reaction of the calcined gypsum (calcium sulfate hemihydrite or anhydrite) with the water to form hydrated gypsum (calcium sulfate dihydrate). It is also well known to produce a lightweight gypsum product by uniformly mixing an aqueous foam into the slurry to produce air bubbles. This will result in a uniform distribution of voids in the set gypsum product if the bubbles do not escape from the slurry before the hardened gypsum forms. The voids lower the density of the final product, which is often referred to as xe2x80x9cfoamed gypsumxe2x80x9d.
Prior apparatus and methods for addressing some of the operational problems associated with the production of foamed gypsum are disclosed in commonly-assigned U.S. Pat. Nos. 5,638,635 and 5,643,510, which are incorporated by reference. The present invention relates generally to the use of foamed gypsum in the production of gypsum wallboard.
A gypsum wallboard mixer typically includes a housing defining a mixing chamber with inlets for receiving calcined gypsum and water, among other additives well known in the art. The mixer includes an impeller or other type of agitator for agitating the contents to be mixed into a mixture or slurry. Such mixers typically have a rectangular discharge gate or slot with a cutoff block or door. The discharge gate controls the flow of slurry from the mixer, and is difficult to adjust to change slurry flow when product requirements change, such as when thicker or thinner wallboard is desired.
Foam and/or other additives are generally added through a foam slot on the outer side of the cut-off block and about 2-4 inches before the gate""s connection to a vertical canister and a donut or restrictor ring. In the production of gypsum wallboard, a balance must be maintained in that the foam is uniformly mixed into the slurry, but not broken down from excessive agitation. Within the canister, which is approximately 5-7 inches in diameter, the material spins downward. The canister is employed to reduce the flow pressure of the slurry discharged from the mixer, which typically operates in the range of 270-300 rpm. One drawback of such canisters is that a centrifugal force set up within the canister causes separation between the materials in the mix due to density differences.
More specifically, recent studies have shown that a vortex is created as the mixture flows in the canister, which also creates an empty air space in the canister. Such an air space is typically representative of unwanted buildup of material in the canister, which then more easily sets and causes clogging of the apparatus. Clogged mixing equipment causes costly downtime for repairs.
Another disadvantage of the vortex created in the canister is that higher density slurry components become separated from the relatively lower density foam. Due to centrifugal force, the slurry is pushed to the sides of the canister and the foam tends to stay in the middle. Thus, rather than providing a site for the uniform mixing of the foam and the slurry, the canister appears to be doing the opposite.
From the canister and donut ring, the material typically flows into a flexible, generally horizontal distribution boot, from where it is dispensed onto the wallboard paper web traveling with the flow of material. In some applications, the slurry is dispensed upon a previously deposited layer of relatively denser gypsum slurry. If the pressure of the dispensed slurry is too high, the previously deposited layer is disturbed, resulting in a condition known as xe2x80x9cwashoutxe2x80x9d.
Typically, a second facing is then applied on top of the slurry to constitute the second face of the gypsum board. Next, the sandwich passes through a forming station which determines the width and thickness of the gypsum board. This process is carried out in a substantially continuous operation, and the gypsum slurry begins to set immediately after the board is formed. Subsequently, the board is dried, cut and bundled into commercially acceptable lengths. Since the uniform mixing of foam within the slurry is a desired result in wallboard manufacture, in view of the drawbacks of the canister, the only places where the foam can mix with the slurry are the mixer gate and the flexible rubber boot.
Thus, it is an object of the present invention to provide an improved gypsum slurry mixing apparatus which does not require a canister.
Another object of the present invention of the present invention is to provide an improved gypsum slurry mixing apparatus and method which promotes uniform mixing of foam into the slurry.
Still another object of the present invention is to provide an improved gypsum slurry mixing apparatus and method which causes a reduction in slurry flow pressure prior to discharge of the mixture upon the wallboard paper and at the same time promotes even mixing of foam into the slurry.
A further object of the present invention is to provide an improved gypsum slurry mixing apparatus and method which reduces maintenance of mixing and dispensing equipment due to premature setting of the slurry.
A still further object of the present invention is to provide an improved gypsum slurry mixing apparatus and method which increases slurry/foam mixing time while not requiring additional length of the board production line.
Yet another object of the present invention is to provide an improved gypsum slurry mixing apparatus and method which provides an easily accessible mechanism for changing the volume of slurry emitted from the mixer.
Accordingly, the above-listed objects are met or exceeded by the present apparatus and method for controlling the output of a slurry mixer including the features of eliminating the canister and its undesirable vortex and replacing it with an extended mixing and dispensing apparatus. The extended mixing and dispensing apparatus gate preferably includes an elongate, preferably flexible conduit which provides additional space for uniform mixing of slurry and additives such as foam, retarders, dispersants and accelerators. By providing a flexible mixing chamber in the conduit, unwanted premature setting of the gypsum is prevented so that occurrences of mixer or conduit lumps and/or paper breaks are reduced. Also, coiling of the chamber is available for applications in which there is limited space in the board line between the mixer outlet and the board forming plate. In the latter application, an extended length mixing chamber is provided which is applicable with board lines having limited space.
Another feature of the present invention is the inclusion of an adjustable pinch or concentric valve located in the preferably flexible conduit for regulating slurry flow to create backpressure in the mixer, which further enhances the uniform mixing action of the foam and slurry. This backpressure also keeps the mixer filled with slurry and thus prevents unwanted premature setting and clogging. When the valve is a concentric valve, it exerts a uniform pressure around the entire circumference of the conduit, which also reduces premature setting and clogging. Regardless of the type of valve, the use of a valve in association with the flexible conduit provides a convenient way to change the volume of dispensed slurry and thus adjust the thickness of produced wallboard as a result.
Yet another feature is the provision of a shock-absorbing device as a part of the conduit to reduce the force or pressure of the dispensed slurry upon the receiving web of substrate or previously dispensed slurry. In the preferred embodiment, the shock-absorbing device takes the form of a generally xe2x80x9cSxe2x80x9d or xe2x80x9cCxe2x80x9d-shaped double bend formation.
More specifically, an apparatus for delivering an additive-enhanced slurry for use in making gypsum wallboard, and configured for connection to a centrifugal mixer with a tangential discharge outlet, includes a conduit having a main inlet in slurry receiving communication with the mixer outlet and extending to a spout for discharging the slurry proximate a wallboard forming area. At least one volume restrictor is associated with the conduit for creating backpressure between the volume restrictor and the mixer outlet for keeping the mixer full, and at least one pressure reducer is associated with the discharge spout and configured for reducing the pressure of the slurry dispensed from the discharge spout. The apparatus is configured for maintaining a generally laminar flow from the mixer outlet to the discharge spout.
In the preferred embodiment, the dispensing apparatus is provided with at least one preferably adjustable valve for creating backpressure in the conduit and mixer, for controlling the flow of slurry from the spout and for reducing buildup of slurry in the apparatus and the mixer. It is preferred that the apparatus, including the preferably flexible conduit portion, be connected directly to the mixer outlet so that generally laminar flow is preserved from the mixer to the dispensing point on the wallboard production line.
In still another embodiment, a method for providing an evenly mixed additive enhanced slurry to a web is provided, including inserting calcined gypsum and water into a mixing chamber of a mixer through one or more inlets of the mixing chamber, agitating the contents of the mixing chamber to form an aqueous dispersion of the calcined gypsum, emitting the agitated contents from an outlet of the mixer, passing the agitated contents into a dispensing apparatus, introducing an aqueous foam into the mixture, creating a backpressure on the mixture in the apparatus by reducing the volume of mixture being emitted from a conduit of the apparatus, the back-pressure being created by constricting the conduit, and controlling the pressure of slurry and foam dispensed from the spout.


A method and information model for carrying out the method are used to control the energy circuits of an object using a generic information model that includes at least one generic unit or generic device that is connected to the energy circuits, the at least one device being assigned to a control unit for each energy circuit, and a device matrix being assigned to the at least one device, in which matrix an energy flow of at least one of the energy circuits is described as a function that includes as a parameter at least one energy flow of at least one of the other energy circuits.

Energy management includes the planning and the operation of units related to energy technology. The goal of energy management is to satisfy the energy requirements of the user, and in particular to realize a cost-efficient and material-efficient energy supply.
In so-called decentralized energy management, the active controlling of the components of an energy circuit of an arbitrary object, such as a building or even an urban district, is supposed to be achieved in order in this way to enable the positive influencing of variables such as power costs or CO2 emissions. In this context, the term "energy" refers to all forms of energy that occur, such as electric current, heat, or mechanical work. Furthermore, it is necessary for some components included in the circuit to allow an automatic controlling. In addition, the entire circuit under consideration must be suitably modeled in order to be able to anticipate the direct consequences of such influencing.
In today's related art, information models for building control technology, and information models for network control technology outside the building, are known. The two information architectures are not linked to one another, and do not cover the requirements of decentralized energy management. For example, the NIST (National Institute of Standards and Technology) makes reference to an incomplete reference list with regard to standards for the linkage of building automation and energy technology. Likewise, neither IEC (International Electrotechnical Commission) nor IEEE (Institute of Electrical and Electronics Engineers) address the integration of the various systems in the building, such as climate control, heating, mechanical work, electric power, light, etc. These named standards, like other previously known standards, do not provide an approach to modeling.
Patent document US 2002/0082747 A1 discusses an energy management system provided for managing the production and distribution of energy from an energy source to a building. The energy management system describes energy producers and energy consumers, the energy producers being described as producers of various forms of energy such as thermal or electrical energy. The building is understood as a consumer of energy. The aim of the presented method is in particular to distribute produced energy in a suitable manner in the building, while carrying out an optimization with regard to costs.
A method is sought by which a uniform modeling of all components of an energy circuit is possible, in order to make it possible to implement an energy management, in particular a decentralized energy management.

Method for controlling the energy circulations in an object


A kiln tool plate for firing a ceramic material used during the firing of an article to be fired, where at least uneven conformations are imparted to a front surface side on which the article to be fired is mounted and a back surface side, and opening areas are formed. In the ceramic material firing kiln tool plate, the decrease of heat capacity and the reduction of costs can be achieved, a contact area with the article to be fired is decreased to improve outgassing, and the atmosphere can be made uniform to uniformly manufacture the fired article. Above all, the kiln tool plate for firing the ceramic material has excellent thermal shock resistance, creep resistance, high strength at high temperature and oxidation resistance, and enables weight saving.

1. Field of the Invention
The present invention relates to a lightweight setter. More particularly, it relates to a lightweight setter for a shelf assembly having a beam structure used to fire a formed honeycomb article.
2. Description of Related Art
Heretofore, as a ceramic material firing kiln tool plate used during the firing of an article to be fired such as a formed honeycomb article, there has been known a ceramic material firing kiln tool plate which comes in contact with the article to be fired and which has a plate shape.
However, when the article to be fired is mounted and fired on the ceramic material firing kiln tool plate having the plate shape, a binder gas included in the article to be fired is not easily discharged, thereby causing a problem that a temperature difference occurs in a product to generate a breakage defect, or another problem that a binder residue during the firing hampers sintering to generate the breakage defect.
Moreover, owing to a large contact area, the binder gas is not easily discharged. In addition, the contact with an atmospheric gas becomes insufficient during the firing, and hence the atmosphere is confined, with the result that the breakage defect is generated. Furthermore, the article is deformed owing to contraction during the sintering to generate the breakage defect. The article easily adheres to a setter owing to the contraction during the sintering, which also generates a problem such as a crack or breakage defect.
To solve such problems, Patent Documents 1 to 3 are suggested as follows.
Patent Document 1 employs a firing kiln tool plate in which a ceramic porous material having pore diameters of about 0.5 to 4 mm is disposed as a supporter, and a surface layer of a surface-like ceramic porous material having bore diameters of 0.5 mm or less is formed on one surface of the supporter. In consequence, a gas permeability to a decomposed gas or the like generated from a lightweight half-finished product is secured, and the thermal strain of the finished product is prevented. In Patent Document 1, however, the ratio of the weight of a kiln tool with respect to a product weight is large, and a large loss takes place from the aspect of energy saving. Moreover, the binder gas is not sufficiently discharged during the firing, so that a temperature difference in the product still easily occurs, and a breakage defect is easily generated. Moreover, the atmosphere is easily confined, and the contact of the product with the atmospheric gas becomes insufficient during the firing, and the breakage defect is further easily generated. Therefore, any concrete countermeasure is not taken against the above problems.
Patent Document 2 is characterized in that a kiln tool plate is constituted of a base plate made of a ceramic material and a plurality of penetration holding portions provided on the ceramic base plate to separately hold electronic parts, respectively, and the shape of each of the penetration holding portions is tapered so that the sectional area thereof decreases from the upper surface to the lower surface. Moreover, the cross section of the penetration holding portion has such a size that at least the electronic part does not pass therethrough. The ceramic base plate of Patent Document 2 employs such a tapered shape that the sectional area decreases from the upper surface to the lower surface, to pass the atmospheric gas through all the holding portions, which is evaluated highly to a certain degree. However, the ratio of the weight of a kiln tool with respect to a product weight is large, a large loss is incurred from the aspect of energy saving, and a binder gas is not sufficiently discharged during firing. Moreover, owing to a large contact area with a product, the product is easily deformed owing to contraction during sintering, and might adhere to the ceramic base plate. In addition, the possibility of the occurrence of a fluctuation during manufacturing, for example, a crack or breakage defect, cannot be denied.
In Patent Document 3, a surface mount portion having an uneven surface structure is formed on the surface of a ceramic base member which comes in contact with an article to be fired, whereby the flow of hot air on a jig can be made uniform to uniformly fire the article to be fired. When such a constitution is employed, the flow of the hot air on the jig can be made uniform to a certain degree. The constitution is evaluated highly to a certain degree. However, it cannot be considered that a binder gas is sufficiently discharged during firing. Moreover, an atmospheric gas is easily confined. In addition, the ratio of the weight of a kiln tool with respect to a product weight is large, and a large loss is incurred from the aspect of energy saving. It cannot be considered that a countermeasure is sufficiently taken against deformation or the like due to contraction during sintering.
As described above, the above problems are not sufficiently solved at present, and a further improvement is demanded.
Patent Document 1: JP-A-5-17261
Patent Document 2: JP-A-6-45209
Patent Document 3: JP-A-6-281359

Kiln tool plate for firing ceramic material


The present invention discloses a process for recovering ammonia from vanadium preparation for ammonium preparation and recycling wastewater. A conventional vanadium extraction process is complex, and the most difficult to control and treat are ammonia emissions and wastewater treatment. The present process can directly extract ammonium metavanadate and ammonium polyvanadate from the beginning of mining and smelting, and gather all emitted ammonia to prepare ammonium in the process of preparing high-purity vanadium pentoxide by using the ammonium metavanadate or the ammonium polyvanadate, thereby ensuring zero emission of the exhaust gas, and effectively treat all wastewater generated in the above process by using a polyacid ester flocculation technology, thereby ensuring that the wastewater is not discharged but recycled, and realizing that the purity of all products reaches 99.5-99.99%.

Vanadium element is widely used in such fields as steel, non-ferrous metals, chemical industry, alloys, superconducting materials and automotive industry, and is an important strategic material.
In nature, vanadium element is extremely dispersed, usually in the form of V (III) and V (IV). V (III) is the majority, and the trivalent vanadium can enter a silicate mineral crystal lattice in the form of isomorphism, while the tetravalent vanadium can exist in a silicon-oxygen tetrahedral structure in the form of isomorphism. Such ores are difficult to leach. To leach the trivalent or tetravalent vanadium, the crystal structures must be destroyed to release the vanadium from the crystal structures.
Conventional vanadium extraction processes can be summarized into two representative types: a roasting vanadium extraction process (a fire method vanadium extraction process) and a wet method vanadium extraction process.
The wet method vanadium extraction process is directly acid-leaching a vanadium-containing ore to obtain a vanadium-containing liquid from a vanadium mineral under a high-concentration acidic condition, even in an environment with the presence of heat and pressure and an oxidant. The fire method vanadium extraction process is subjecting an ore to high-temperature oxidation roasting to oxidize and convert low-valent vanadium into pentavalent vanadium, and then wet-leaching to obtain a vanadium-containing liquid to extract vanadium from the ore. In the roasting vanadium extraction process, stone coal is subjected to salt-added oxidizing-sodiumizing roasting to form a vanadium-containing clinker; the vanadium-containing clinker is directly leached with process water (i.e. water immersion) to obtain a leachate having a lower vanadium concentration; ammonium chloride is added to precipitate vanadium to obtain an ammonium metavanadate precipitate, and then crude vanadium pentoxide (crude vanadium) is obtained by roasting; the crude vanadium is subjected to alkali dissolution, impurity removal, and secondary vanadium precipitation by ammonium chloride to obtain ammonium metavanadate; the ammonium metavanadate is thermally decomposed to obtain a vanadium pentoxide product having a purity of more than 98%, thus forming a "a sodium roasting, two-step vanadium precipitation process" or a "salt-added roasting vanadium extraction process". Alternatively, lime, limestone or any other calcium-containing compound is used as an additive to pelletize with the stone coal for roasting, so that vanadium is oxidized into a water-insoluble calcium salt of vanadium; then the calcium salt is carbonated and leached to form a vanadium-containing solution, which is then leached with an acid or a dilute alkali solution; subsequently, hydrolyzation vanadium precipitation, dissolved extraction or ion exchange is performed, and pyrolysis is used to refine the vanadium.
In short, after the vanadium ore is roasted with a salt to form the vanadium-containing clinker, water, an acid or an alkali must be used to leach the trivalent vanadium, tetravalent vanadium or pentavalent vanadium from the vanadium-containing clinker; then the vanadium salt is separated from other components in the leachate by extraction and back extraction or ion exchange; finally the vanadium salt reacts with ammonia water or any other ammonium salt to form an ammonium metavanadate precipitate, and the ammonium metavanadate precipitate is thermally decomposed to obtain a vanadium pentoxide product having high purity.
However, in the roasting vanadium extraction process, ammonia or the like gas will be reversed out of a roaster, and when the acid (sulfuric acid) is used for leaching, a large amount of wastewater will be generated; the wastewater contains sulfuric acid and sulfur dioxide, and even if a neutralization treatment is performed, the wastewater still contains sulfate and other harmful substances (such as ammonia nitrogen and residual sulfate radical). The conventional vanadium extraction process is complex, and the most difficult to control and treat are ammonia emissions and wastewater treatment. If the ammonia and wastewater generated in the above process are not treated technically, it will not only waste resources, but also cause environmental pollution to rivers and lakes, and even cause harm to human drinking water sources.

Process for recovering ammonia from vanadium preparation for ammonium preparation and recycling wastewater

Zhongfanlian Technology Development Co., Ltd.


In one implementation, a housing has a first surface and a second surface. A first side may be between the first surface and the second surface. An input device on may be on the first surface. A sensor on the first side may generate data representing an object detected by the sensor. A controller may process the data and control movement of the cursor on a display when the controller determines that the object is in the shape of a hand in a grip form.

Computing devices with graphical user interfaces can include pointing devices such as a mouse or a touchpad. The pointing device generates signals that cause a change to the graphical user interface. A mouse is an accessory that attaches to the computing device. A touchpad may be integrated into the computing device such as the palm rest of a notebook computer.

Hewlett-Packard Development Company, L.P.


In general, techniques are described that insert one or more bits into a digital bit stream to maintain an overall transition density in the digital bit stream. Maintaining the overall transition density facilitates the generation of a recovered clock by a phase-locked loop (PLL) circuit of a receiver. For example, when a data transition ratio for a portion of the digital bit stream is less than a desired data transition ratio, the techniques insert additional bits to increase the overall transition density of the digital bit stream.

Many devices that receive high-speed digital bit streams utilize a technique referred to as "clock recovery" in which a receive clock for processing the bit stream is not communicated separately from the bit stream but instead generated from the transmitted bit stream. Often, the receiving device utilizes a phase-locked loop (PLL) circuit to generate the receive clock for processing the received digital bit stream. A PLL circuit relies on data transitions in the received digital bit stream to generate the receive clock at the proper frequency and phase transitions. For example, the PLL circuit compares the time when a data transition occurred in digital bit stream to a time when a rising or falling edge occurred in the generated receive clock. The PLL circuit controls the phase of the receive clock based on the comparison to generate a phase-locked receive clock that aligns with the transitions with the communicated data.

Digital bit insertion for clock recovery