The current invention relates to a conductivity-dielectric (CD) electrode design with apertures that allow compressional waves to propagate away from the surface of the acoustic wave device unimpeded. This prevents reflection of compressional waves that would interact with the viscosity sensor surface, thus altering the device response. It allows compressional waves to pass through, and allows the dual mode viscosity sensor responses to be utilized for density/viscosity/elasticity measurement and correlation. The invention further offers methods of instrumentation to detect unwanted reflections, to compensate, and to correct for the distortions caused by reflections. Finally, the invention provides a system and method for utilizing deliberately introduced reflections to obtain additional information, including fluid density.

There is a growing demand for multi-measurand measurement of fluid properties in industrial settings. A notable example is in the monitoring of fuels, lubricants, hydraulic fluids, and coolants in which fluid aging and fluid contamination must be monitored and subjected to trend analysis to optimize preventive maintenance schedules. Typically these applications require viscosity measurement for immediate detection of catastrophic failure and employ conductivity and/or dielectric measurements for predictive measurements. Often, the measurement principles most amenable to in situ measurement have several secondary effects that distort the measurements from those obtained using lab equipment. Furthermore, other fluid physical properties are often desired in order to qualify the cause of a viscosity change.
Despite over 20 years of effort to develop a low-cost, high performance, multi-measurand fluid condition sensor, there is no single measurement approach that is suited to simultaneously detecting all of the fluid properties of interest for lubricants, fuels, hydraulic fluids, and coolants, such as fuel dilution, soot loading, water and glycol contamination, additives depletion, and wear particle detection.
While many approaches have been proposed to monitor these properties, vibrating sensors—especially the solid state implementations based on piezoelectric devices that impart acoustic energy onto the fluid—have shown the most promise. Generally, the measurable parameters are non-linear functions of a harmonic frequency, ω, and the driving signal amplitude of the sensor. Since the functional forms are known, and since the prior art provides methods of instrumentation of the frequency dependence and amplitude dependence, it is possible to address these effects. Using the prior art in conjunction with the present invention, it is possible to characterize the dependence in some applications and possible to correct the values back to laboratory conditions in other applications. Of particular interest is the rheology of a fluid, specifically the relationship between shear stress and the rate of shear strain as a function of the rate of shear strain and the harmonic frequency of shear strain. Many pseudo-plastic models are well known in the literature.
For clarity, this application will refer to such vibrating piezoelectric device based sensors as Acoustic Wave Device or AWD. A resonant AWD is considered herein a device comprising a crystalline material having a plurality of electrodes that provides movement of the crystal face in response to electrical power presented between at least an input pair of these electrodes, and conversely generates an electrical signal at an output pair of electrodes in response to power applied to the crystal face. One or more electrodes may be common to both input and output pairs, and the input pair may also serve as the output pair. The term extends to Thickness Shear Mode (TSM), Surface Acoustic Wave (SAW), Surface Transverse Wave (STW), Bulk Acoustic Wave (BAW), Quartz Crystal Microbalance (QCM) and the like. An AWD may operate using plate mode, thickness mode, shear mode and shear thickness mode, bulk wave, love wave, and the like, and may utilize any convenient cut or material. Quartz, langasite, langatate, gallium phosphate, lithium niobate, and lithium tantalate are widely reported for sensor applications using AWD, and many newer materials are expected to have promise in this emerging field that expressly fall within the AWD definition. It is noted that a single AWD commonly has more than one resonant frequency, each equivalently related to as a 'mode' or a 'resonant mode'. Furthermore, even devices designed to be 'single mode' devices have unwanted, spurious modes.
Obtaining information about the environment in which the AWD operates makes the AWD into a sensor. However, the sensor needs to be coupled to equipment—circuitry, computing device, and the like so as to provide useful information. The connection method, support circuitry, and manners of decoding the information are colloquially known as the 'instrumentation' of a device, and providing said instrumentation is known as 'instrumenting' the device.
Numerous piezoelectric acoustic wave device (AWD) technology based sensors are known that potentially satisfy at least subsets of the need. By way of example, quartz tuning forks were disclosed in U.S. Pat. No. 6,401,519 to McFarland et al., corrugated thickness shear mode (TSM) sensors were disclosed in U.S. Pat. No. 5,741,961 by Martin et al., and corrugated surface transverse wave (STW, Love mode) were disclosed by Hermann et al. in U.S. Pat. No. 6,543,274. The monolithic piezoelectric sensor (MPS) of Andle as taught in U.S. Pat. No. 6,033,852, the corrugated MPS of Andle as described in U.S. Pat. No. 7,552,619, the high pressure composite resonators of Andle as described in US Patent publication 2009-0309453 and US patent publication 2010-0052470-A1, the multi-mode, quasi-shear horizontal resonator (MMQSHR) of Andle, as disclosed in US Patent publication 2009/0216467 and WO2009/105354, the lateral field excited TSM of Vetelino as disclosed in U.S. Pat. No. 7,075,216, and the coplanar circularly polarized transducer (CCPT) of Andle, as disclosed in U.S. patent application Ser. No. 12/404,288 constitute newer examples. The CCPT comprises a plurality of electrodes formed on a common surface (planar or curvilinear) such that one or more electrodes form a functionally closed shape, the plurality of electrodes forming a plurality of shapes, each of those shapes being functionally fully enclosed by, or fully enclosing, another shape and defining a gap therebetween. The electrodes therein are defined as coplanar circularly polarized electrodes (CCPE) and a CCPT comprises a plurality of coplanar circularly polarized electrodes separated by at least one gap therebetween. 'Functionally closed shape' implies that a small gap or gaps in the shape may be introduced that, while geometrically breaking the closed shape, will have minimal effect on the circular polarization induced by the CCPT. This transducer may be applied to a variety of AWD's but is most effective while used to create lateral field excitation in a thickness shear mode (TSM) device.
All the above identified patents, patent publications, and patent applications are incorporated herein by reference in their entirety.
Early work by Sandia National Laboratories and others, S. J. Martin, V. E. Granstaff and G. C. Frye, "Characterization of a Quartz Crystal Microbalance with Simultaneous Mass and Liquid Loading", Anal Chem 1991, 63, 2272-2281, demonstrated both the applicability and limitations of quartz thickness shear mode (TSM) sensors. Five significant limitations of the early TSM sensors are (a) the time constant of the static capacitance in parallel with the motional resistance limits measurement range and resolution, (b) the low piezoelectric coupling (k2) of quartz limits measurement range of the motional resistance for a given instrumentation system, (c) Maxwellian properties of real fluids deviate substantially from the Newtonian model above ˜1 MHz for typical hydrocarbons and (d) incidental compressional wave components that are inherent to TSM energy trapping are known to cause an erroneous reading of the viscous losses, and (e) reflections of these compressional waves from an opposing surface establish resonances within the fluid between the crystal face and an adjacent reflective surface.
A quartz-based monolithic crystal filter (MCF) was introduced by Schweyer et al. in 1997, M. Schweyer, J. Hilton, J. Munson, J. Andle, J. Hammond, R. Lec & Q. Lin, "A Novel Monolithic Piezoelectric Sensor", 1997 IEEE International Ultrasonics Symposium, pp. 371-374 and M. Schweyer, J. Hilton, J. Munson, J. Andle, J. Hammond and R. Lec, "A novel monolithic piezoelectric sensor", 1997 IEEE International Frequency Control Symposium, pp. 32-40, as a solution to the parallel loading of the static capacitance of single port TSM devices. The topology of the MCF places the static capacitance as two shunt elements in parallel with the source and load resistances and not in parallel with transmission through the motional circuit, extending the constraints of (a), above.
In order to ease measurements of fluid parameters utilizing a resonant AWD, it is well known to model the device after an equivalent electrical circuit or transmission lines which approximately relate one or more simplified measurable electrical parameters to one or more physical properties of the fluid. It is common to model the behavior of the AWD in a single resonant frequency by a simple equivalent electrical series resonance circuit comprising a resistance Rm, inductance Lm, and capacitance Cm, connected in series. The subscript, m, denotes a motional property seen through the acoustic to electrical "transformer ratio" of the piezoelectric effect. Such reduced equivalent circuit models are employed for computational simplicity and conceptual clarity.
FIG. 1a shows the equivalent circuit of the prior art single-port TSM and FIG. 1.b shows the equivalent circuit of the prior art Monolithic Piezoelectric Sensor, more recently embodied as a Multi-Mode Quasi-Shear-Horizontal Resonator (MMQSHR). In the original TSM, the physical static capacitance 101 of the electrodes is in parallel with the resonant transmission path 102, represented by series motional resistance 103, motional capacitance 104, and motional inductance 105. In the MMQSHR the static capacitance is split into an input 111 and output 112 capacitance, neither of which is in shunt with the transmission paths 113 and 114. Transmission path 113 has 0° of phase shift at its series resonance and is modeled by a motional inductance 115, capacitance 116, and resistance 117. Transmission path 114 has 180° of phase shift at its series resonance and is modeled by a motional inductance 118, capacitance 119, and resistance 121 with a 180° phase shifter 121.
This relocation of the physical capacitance precludes the need for complex compensation schemes and also allows operation of a TSM sensor with isolated electrical connections impervious to electrical perturbations by the fluid. Furthermore, the use of a low source impedance excitation circuit and a low load impedance current measurement detector allows the measurement of the transfer admittance, Y21, of the element, eliminating the residual effects of these physical transducer static capacitance elements.
A swept frequency transmission circuit may be employed to extract the motional resistance from the sampled transfer function data and track the resonant frequency over perturbations due to pressure, temperature, and viscosity. A number of methods allow the measurement of the real part of the transfer function. The transfer function might be S21 as measured by a vector network analyzer, H(F) as measured by the detected RMS voltages, or Y21 as the ratio of the short output circuit current to the input voltage. For a 50Ω load, a sufficiently small static capacitance and a sufficiently large motional resistance, the real parts of S21, H(F), and 50*Y21 are reasonably interchangeable with only moderate changes in the calibration curve.
FIG. 2 shows one such embodiment as a preferred embodiment of the instrumentation circuitry for an MMQSHR. Low impedance voltage source 210 excites MMQSHR 220 whose short circuit output current is amplified by transimpedance amplifier 230. The low impedance of the voltage source and the current to voltage amplifiers render physical capacitances 111 and 112 insignificant. As a result, the ratio of the output voltage of amplifier 230 to the source voltage 210 is the transfer admittance, Y21, of the MMQSHR times the feedback resistance, RF 231 of the amplifier. In one embodiment of the instrumentation the in-phase drive signal 210 is phase shifted 215 to obtain a quadrature signal, and the drive signals are optionally buffered 235, 240 to drive mixers 240, 245 resulting in down-converted in-phase 250 and quadrature 255 magnitude signals. As the frequency of source 210 is varied, the voltages at 250 and 255 are representative of the real and imaginary parts of Y21, namely the transfer conductance and transfer admittance, respectively. The transfer admittance is readily curve fit to obtain the elements of the equivalent circuit of FIG. 1.a under the limit of trivially small compressional wave reflections.
Performance of the quartz-based MCF structure was still limited by piezoelectric coupling; however the limitation was scaled to higher viscosities by removal of the static capacitance from its previous location in shunt with the motional resonance to be measured. The development of lanthanum gallium silicate (LGS) and other higher coupling, quartz-like piezoelectric crystals, allowed successful devices to be demonstrated. These materials have higher acoustic impedance and a higher coupling. Higher acoustic impedance results in less sensitivity to fluid damping and higher piezoelectricity results is a lower ratio of electrical equivalent circuit motional resistance to physical damping. In 2007, J. Andle, R. Haskell, R. Sbardella, G. Morehead, M. Chap, J. Columbus and D. Stevens, "Design, packaging and characterization of a two-port bulk wave langasite viscometer", IEEE Sensors 2007, pp. 868-871, overcoming limitation (b), above.
Since many large-scale applications are for trending (aging) of in-service fluids, the deviations from Newtonian are seen to be tolerable at 5 MHz. Prior work including K. Durdag and J. Andle, "Portable/Handheld Oil Assessment Device Project: NCMS Collaborative Agreement No: 200640-140414", Final Report, Nov. 12, 2007 (unpublished), K. Durdag and J. Andle, "Real-Time Viscosity Measurement for Condition-Based Monitoring Using Solid-State Viscosity Sensor", Tribology Transactions, 51:296-302, 2008, and Andle J., Durdag K., Chap M., Haskell R., Threaded Fluid Condition Sensor for Real-Time, On-Line and In-Line Oil Conditioning Monitoring, in Proceedings of SENSOR+TEST 2009 Conference, Nuremberg, Germany, 26-28 May 2009, Vol. II, pp. 229-234, shows good correlation within broad classes of lubricants between the "acoustic viscosity" ("AV"=ρη) measured in an oscillator-based LGS MCF sensor system and the laboratory measurements of either intrinsic viscosity (η) or kinematic viscosity (η/ρ) with a linear correlation term regarding (c) above. Nonetheless, it is still desirable to eliminate the need for correlation, as well as to measure the density and even the compressional modulus of the material.
To this end, U.S. application Ser. No. 12/780,869, filed May 15, 2010 and entitled "Improved Measurement of Fluid Parameters", provides a method of transformation of the six equivalent circuit parameters into four linearized "input parameters". Two input parameters relate to energy loss (linearized motional resistance) of the two resonant transmission paths, and two input parameters relate to frequency shift (linearized motional inductance) of the two modes.
An important feature of selected aspects of the '869 application is the utilization of actual measured motional capacitance values extracted from equivalent circuit fitting of the sensor in the reference and/or measurement state, rather than the prior art use of the ideal motional capacitance as a calculated sensitivity parameter of the motional resistance to loading. Yet another important feature is the utilization of nonlinear products of motional resistances and motional capacitances (the "RC product") at each of the selected resonances, individually extracted in the equivalent circuit fitting, as a "loss" input parameter to at least one computing function. The use of the RC product in the loss parameter linearizes the sensor response. Similarly the nonlinear product of resonant frequency, motional inductance, and motional capacitance (the "ωLC product") of the selected resonances, individually extracted in equivalent circuit fitting, may be employed as a "frequency" or "phase" input parameter to at least one computing function to optimally linearize the sensor response. It is found to be advantageous to take the difference of the RC products and ωLC products between the measurement state and the reference state. It is further found that multiplication of these differences by the unloaded/reference resonant frequency, ωo, optimally normalizes the problem. The properly normalized system allows a complex input parameter, Im, to be defined for each selected mth resonance having anharmonic number m. The complex input parameter has a real part being the loss input parameter Lm, and the imaginary part being the frequency input parameter, Pm. By analogy and the duality principle of circuit theory, it is equally acceptable to employ the R/L ratio as a loss parameter and preferably the R/ωL ratio for normalization. This is demonstrably identical to the RC and ωRC products, respectively, and is considered identical throughout the present disclosure. Similarly, ωLC is recognized as 1/ω. Therefore, 1/ω is considered identical to the ωLC product.
Thus, in the '869 application, there is provided a method of measuring the fluid mechanical properties utilizing a resonant acoustic wave device (AWD). The method begins by measuring a reference state transfer function of the AWD at a plurality of frequencies about at least one selected resonant frequency of the AWD. Equivalent circuit parameters are extracted describing the transfer function in accordance with an equivalent circuit model. The parameters are reflective of a motional resistance, a motional inductance, and a motional capacitance, which are the equivalent circuit parameters in the preferred model. After the AWD is measured in a reference state; the AWD sensor is utilized in a loaded/measurement state by imparting to the AWD a viscoelastic load of the fluid to be measured. The transfer function of the loaded AWD is again measured at a plurality of frequencies about at least one resonant frequency. The loaded equivalent circuit parameters describing the transfer function are again extracted. After the extraction of the equivalent circuit in the measurement state and the reference state, the fluid mechanical properties are calculated by defining at least one input parameter associated with the resonant frequency comprising a nonlinear combination of the equivalent circuit parameters and defining at least one output parameter related to the fluid properties, employing at least one linearized computing function relating the at least one output parameter to the differences of the input parameters from the reference to the loaded state, and calculating output parameters. The fluid mechanical property is then calculated from the output parameters of the computing function utilizing known relationships defining the output parameter in terms of the fluid properties. A one for one correspondence exists between a computing function and the output parameter that is computed.
The computing function will typically include one or more adjustable terms, called "calibration coefficients". These coefficients may be assumed, estimated, or measured experimentally.
The balance between loss and frequency parameters is indicative of the shear viscoelastic relaxation time of the fluid. Barlow and Lamb first applied this principle to quartz sensors, in the absence of any compressional mode considerations, in their paper, "The Visco-Elastic Behaviour of Lubricating Oils under Cyclic Shearing Stress", Proc. R. Soc. Lond. A 1959 253, 52-69. This approach is expanded upon in the '869 application and also in U.S. application Ser. No. 12/780,868 filed May 15, 2010, entitled "Improved Calibration of High Frequency Fluid Phase Acoustic Sensors". These applications disclose methods of simultaneously instrumenting the sensor to obtain a radiation resistance associated with compressional wave radiation, hence a product of density, ρ, and compressional elastic modulus, κ, as well as the viscoelastic relaxation time, τ, in addition to the better known product of dynamic viscosity, η(ω), and density, ρ. The '868 application, which is incorporated herein by reference in its entirety, determines the calibration coefficients by imparting viscoelastic loads to such AWD's from a plurality of known static load conditions and measuring transfer functions of the AWD about at least one resonant frequency under those known load conditions. Initial values of the calibration coefficients are selected and then an iterative process is carried out in which an error function is determined between a selected parameter measured by the AWD, or calculated from such measurement, and a corresponding ideal parameter derived from the known calibration fluid. Once the error function is determined, the calibration coefficients are adjusted and the calculation is iterated until the error function falls to within an acceptable tolerance. Importantly, the calculation utilizes the estimated viscoelastic relaxation time of the non-Newtonian calibration fluids as measured by the AWD using the assumed calibration coefficients. The computation of the ideal parameter utilizes an estimation of the shear viscoelastic relaxation time of the fluid at the resonant frequency to estimate fluid static fluid parameters from the measured parameters and adjusting this relaxation time as dictated by the adjustments in the calibration coefficients. One result of this method allows calibration of high frequency AWD sensors for viscoelastic property measurement using fluids that are non-Newtonian at the operating frequency of the AWD and for which only static viscosity information taken under Newtonian operating conditions is available. Utilizing the actual, measured motional capacitance in a manner similar to that of the present application provides a preferred method of obtaining the viscoelastic relaxation time, which simplifies the calculation of the calibration parameters.
FIG. 3 shows the response of an MMQSHR device employing split elliptical electrodes with total length 3.5 mm, total width 2 mm, and crystal thickness 0.26 mm manufactured on Y-cut lanthanum gallium silicate (LGS). The ground plane surface was loaded with test fluids, and the change in the measured motional resistances of the first and second resonant modes from the reference states were measured at several temperatures in accordance with the prior art calculations shown supra. FIG. 3 represents an attempt to graphically provide a computing function using the frequency-normalized shear acoustic impedance. Solvay-Solexis' perfluoro-polyether, HT270, is a fluid that is reasonably Newtonian at 5.25 MHz and that has been used as a viscosity standard. It shows highly linear relationships for the first (00) mode 301 and the second (10) mode 302. The slopes of these curves are substantially different, an effect for which there is no correction mechanism in the prior art theory, prior to the '869 application, using motional resistance or frequency.
A Cannon mineral oil standard, N250, is seen to exhibit an upward curvature in the response, indicative of a relaxation time that increases with increasing viscosity (decreasing temperature). Again, the two modes 303, 304 have significant differences in sensitivity. It is not possible to reliably use this measurement to obtain the differential resistance due to compressional effects 305, 306 or to obtain reliable, repeatable, and accurate viscoelastic effect measurements because of the nonlinearities of the system.
The measured value of the compressional wave radiation may be used to correct the one-dimensional estimate of the shear (viscosity) term. Direct measurement of the motional resistance (1/gmax) or estimation using curve fitting at the two modes allows matrix methods to be employed to solve the system of equations relating the shear and compressional acoustic impedances to the change in motional resistance from the nominal air value.
In the prior art, the two observables depend on two measurands, ZS and ZC, which are the tangential and compressional "acoustic impedance" values of the fluid, (2ωρη)1/2 and (ρκ)1/2, respectively in the Newtonian limit. A system of linear equations may be written in terms of the shear acoustic impedance and the compressional acoustic impedance. The normalized shear impedance squared is called "acoustic viscosity", expressed as "AV" with units of Pa-s-kg/m3. According to the '125 application, a simple relationship can be provided for as:
            [                                                                  R                S                            -                              R                                  S                                                                                0                                                                                R                A                            -                              R                                  A                                                                                0                                                                        ]        =                  [                                                            K                ST                                                                    K                SC                                                                                K                AT                                                                    K                AC                                                    ]                          [                                                            Z                S                                                                                Z                C                                                    ]              ,where RS0 and RA0 are the symmetric and anti-symmetric resistances in air, respectively. In keeping with the '869 application, the symmetric mode is mode 0 and the antisymmetric mode is mode 1. The constants KST, KSC, KAT and KAC relate ΔRS and ΔRA to ZT and ZC. Inverting this relationship obtains a so-called computing function that would provide the acoustic impedances of the shear and compressional waves from the two measured motional resistances. The math assumes linear loading of the acoustic transmission line which requires ρκ<<ρSC22 and 2ωηρ<<ρSC66 where subscript S denotes the substrate density.
Knowing the two resistance values in air and in the fluid and knowing the matrix of parameters provides a system of linear equations according to the '125 application. The system of equations not only obtains the density-viscosity product as ZS2, but also compensates residual measurement errors due to unreflected compressional wave radiation provided that the determinant of the coefficient matrix is non-zero. Finally, additional information on the value of the compressional impedance squared gives the elasticity-density product, ρκ. Frequently KST˜KAT since both modes have comparable energy trapping profiles and shear wave components.
Therefore, the requirement for measuring density-elasticity (compressional impedance) is that KAC≠KSC. This is reasonably ensured using a thickness shear (X-propagating) coupled resonator as opposed to a thickness twist (Z-propagating) coupled resonator with thickness field excitation and by having good energy trapping. Thickness twist anharmonics are desired in certain lateral field coupled resonators. For an ideal resonator, having one half wavelength of energy trapping across the diameter of the resonator for the symmetric mode and a full wavelength for the anti-symmetric mode, there is a four to one ratio of these terms. Evanescent decay beyond the energy trapping region decreases the ratio.
The changing Ux(x) will result in different anharmonics having different sensitivity to compressional radiation but similar sensitivity to viscous loading as seen in FIGS. 3 and 4. This sensitivity arises from the ratio of compressional displacements to shear displacements, which is known from energy trapping considerations. The square of this ratio is denoted as θm for the mth anharmonic herein.
The solutions for the change of motional resistance 117, 120 due to fluid loading are all linearized by the real motional capacitance measured for the mode in the '869 and '869 applications. Mode shapes that are not consistent with the one dimensional model will result in very substantial changes of the sensitivity slope itself. This is compensated in these applications in the absence of compressional ripple.
FIG. 4 shows the measured response of the same MMQSHR device as depicted in FIG. 3, under the same conditions, however the improved response is obtained utilizing techniques disclosed in the '869 application. The change in the product of the measured motional capacitance and measured motional resistances (ΔRC) of the first and second resonant modes from the reference states were employed as the input parameter for two resonances. FIG. 4 provides a graphical representation of a computing function to obtain the frequency-normalized shear acoustic impedance, (ρη)1/2 as the output parameter relative to the resistance-capacitance product as measured under Newtonian conditions, e.g. using an Anton-Parr SVM-3000. HT270 is a Newtonian viscosity standard and shows highly linear relationships for both transmission paths.
The slopes of these curves are substantially identical, demonstrating the efficacy of linearizing the input parameter through multiplication of the measured motional resistance by the measured motional capacitance. The example output parameter is suitable only for Newtonian fluids and presents a nonlinear computing function for other fluids. The additive effects of compressional radiation 405 and 406 are clearly visible. Mineral oil standard, N250, is seen to exhibit an upward curvature in the response, indicative of a non-Newtonian relaxation time that increases with increasing viscosity (decreasing temperature). Again, the two modes 403, 404 have significantly identical curvature and track well, allowing other processes such as Maxwellian viscoelasticity and compressional wave radiation to be clearly observed.
When fluids are Newtonian, the added motional resistance 117, 120 is equal to the product of the resonant radian frequency and the added motional inductance 115, 118. It is often stated that a TSM sensor cannot measure fluids beyond this range and that low frequency tuning fork resonators are desirable. However, the fundamentals of Maxwellian and Kelvin-Voigt pseudo-plastic fluid analysis using a TSM resonator and the extraction of the viscosity in the limit of low frequency, called the static viscosity herein, are well known, as witnessed by the aforementioned 1959 work of Barlow and Lamb.
Because of the linearity introduced by the present invention it is now possible to obtain reasonable estimates of the Maxwellian viscoelastic effects while simultaneously measuring compressional mode radiation. The mechanical impedance, ZS, (ratio of stress to the time derivative of strain) is given for the shear wave in the Maxwellian model as
      Z    S    =                    R        S            +              j                                                            X          S                      =                  jωρη                  (                      1            +            jωτ                    )                    where ρ is the fluid density, η is the static viscosity of the fluid, μ is the clamped shear rigidity modulus of the fluid, τ is the molecular relaxation time of the fluid, equal to the ratio of the static viscosity to the clamped elastic rigidity modulus, γ/μ, and, for Newtonian fluids, τ=0.
In order to practice aspects of the invention in non-Newtonian fluids, the complex shear acoustic impedance, ZS, is then squared and the non-Newtonian relaxation time constant, τ, is obtained by dividing the real part of the square of the shear acoustic impedance by the product of the frequency and the imaginary part of the square of the shear acoustic impedance. The imaginary part of the square of the shear acoustic impedance, the frequency, and the time constant are then employed to obtain the static viscosity-density product and the clamped elastic rigidity modulus-density product is then obtained as the static viscosity-density product divided by the relaxation time,
      τ    =                  Re        [                  Z          S          2                ]                    Im        [                  Z          S          2                ]              ,                ρη    =                            Im          [                      Z            S            2                    ]                ω                          (                  1          +                                    ω              2                                                  τ              2                                      )              ,                ρμ    =          ρη      τ        ,
In order to assess the role of non-Newtonian relaxation time, an approximation ignoring compressional effects is given. The results for the device used to generate FIG. 4 are shown in FIG. 5 wherein the scale calibration of the shear impedance and the compressional effects were ignored. The result was obtained only when viscosity was sufficiently large to safely ignore compressional effects. For a 5.25 MHz sensor frequency, the characteristic time of the measurement, 1/ω, is on the order of 30 ns. HT270 at 0° C. exhibited 2.9 ns and is still quite Newtonian. The errors associated with ignoring ω2τ2 are 1% in this case. Meaningful Maxwellian influence is seen for the mineral oils with ω2τ2˜1 and a 50% decrease in apparent viscosity for N250 near −25° C. at 5.25 MHz. Efforts to separate the relaxation time effects and the compressional radiation effects have been hampered by compressional wave reflections.
The example operating frequency of 5.25 MHz results in a characteristic time of approximately 30 ns. Operation between an approximate lower limit of 1 MHz and an approximate upper limit of 25 MHz does not significantly alter the qualitative response of the sensor to mineral oils but merely shifts the specific relaxation time at which there is an observable effect. Maxwellian fluids have relaxation times ranging from about 1 ns for water to tens of nanoseconds for mineral oils to microseconds for silicones. While correlation is acceptable, a direct correspondence is preferable.
The methods offered in the Barlow and Lamb prior art and in the '125 application are limited to the case in which there is no reflection of the compressional mode energy back into the sensor from an opposing surface. It is therefore one objective to eliminate reflections and another objective to verify the quality of a measurement based on this assumption.
Prior art FIG. 6, taken from the '869 Application, illustrates the steps of measuring a transfer function (610 iterating over discrete frequency samples, 615 measuring discrete transfer function values, 620 testing if the iteration is complete, 615 obtaining the transfer function, and 630 extracting the equivalent circuit through one of many available curve fitting methods) for the reference state 605 and repeating these steps 655 in a loaded state 650. It also discloses determining input loss parameters 660 and/or input frequency parameters 665 and calculating output parameters 670 corresponding to the calibrated loaded state of the device. Finally, it discloses the calculation of relaxation time 675, dynamic viscosity-density product 678, static viscosity-density product 680, dynamic rigidity-density product 682, clamped rigidity-density product 685 and compressional elasticity-density product 690. It is noteworthy that the step of extracting the actual fluid properties requires independent knowledge of the density, which is a parameter of interest in its own right. It is also notable that the selection of the equivalent circuit of FIG. 1.b and the selection of only four input parameters restricts the '869 Application to certain operational conditions with regards to the reflection of radiated compressional energy back into the device. While the '869 Application offers a means of estimating the fluid compressional impedance in a finite cell and of determining the compressional elasticity-density product, there is needed a better method of implementing the computing function 670 employing additional input parameters or of overcoming the reflections in the first place.
The '869 application provides for the analysis and instrumentation of AWD resonant sensors having reflected compressional waves, provided the path length of the reflections is sufficiently short to allow the use of a lumped element model.
Judicious installation and design of sensor packaging may overcome reflected compressional wave issues to within a reasonable limit of accuracy sufficient for a trending analysis and asset management tool. However, the miniaturization inherent to increasingly higher operating pressures and the integration of additional sensing structures further complicates the compressional wave effect. Efforts to mitigate the reflections in a multi-measurand sensor are reported by J. Andle, R. Haskell and M. Chap, "Electrically Isolated Thickness Shear Mode Liquid Phase Sensor for High Pressure Environments", 2008 IEEE Ultrasonics Symposium, pp. 1128-1133, included in whole in U.S. Provisional Patent Application, 61/243,685 filed Sep. 18, 2009, from which the present application derives.
The mitigation resulted in a relatively constant motional resistance term due to viscosity that was approximately equal for the multiple modes and another motional resistance term that increased with increasing mode number in answer to limitation (d) above. The methods reviewed above also treat this case, allowing an MMQSHR to simultaneously measure the viscosity-density product, the compressional modulus-density product, and the viscoelastic relaxation time in the absence of reflected compressional mode energy. Careful installation and operation of the sensors allows these conditions to be met; however, the attendant restrictions are too burdensome on end users. Therefore, while the prior art has also addressed limitation (e) above to a limited degree, a better solution is desired.
FIG. 7 shows a measurement of viscosity-density product in accordance with U.S. application Ser. No. 12/780,869 for a measurement set with ("Reflective Fixture—REF") significant compressional reflections 701 and without ("Antireflective Fixture—AR") 702 significant compressional reflections, as described in the present invention. The reflective fixture employed a flat, parallel surface opposite the sensor while the antireflective surface comprised a conically tapered surface intended to scatter the reflections. The reflection signal's phase is a function of temperature due to the variations of phase velocity with temperature in the fluid.
The reflected signal causes an additional loss term at the points of destructive interference that are misinterpreted as additional viscosity. At the points of constructive interference the radiated energy is all returned, and the result is equivalent to having no radiated compressional energy in the first place. It is clear that the prior art method is incapable of tolerating significant degrees of compressional reflection. While the antireflective fixture measurement 702 of FIG. 7 shows considerably less ripple than the reflective fixture, it is still not a perfect example of anti-reflective fixturing. Furthermore, some reflection existed in the calibration fixture and is therefore permanently factored into the sensor response.
The overall curve of viscosity vs. temperature shows the unwanted influence of the reflections. However, in any single measurement of the fluid at any given temperature, it is not possible to tell with any degree of certainty whether or not the data is corrupted by the value of the measurement itself. It is only apparent that compressional reflections are significant when viewing the data as a whole.

Controlled compressional wave components of thickness shear mode multi-measurand sensors


The disclosed embodiments provide a system that manages use of a solid-state battery in a portable electronic device. During operation, the system monitors a temperature of the solid-state battery during use of the solid-state battery with the portable electronic device. Next, the system modifies a charging technique for the solid-state battery based on the monitored temperature to increase a capacity or a cycle life of the solid-state battery. To modify the charging technique based on the monitored temperature, the system may increase a charge rate of the solid-state battery if the temperature exceeds a first temperature threshold. On the other hand, the system may maintain the charge rate of the solid-state battery if the temperature does not exceed the first temperature threshold.

Field
The disclosed embodiments relate to batteries for portable electronic devices. More specifically, the disclosed embodiments relate to charging techniques for solid-state batteries in portable electronic devices.
Related Art
Rechargeable batteries are presently used to provide power to a wide variety of portable electronic devices, including laptop computers, tablet computers, mobile phones, personal digital assistants (PDAs), digital music players and cordless power tools. The most commonly used type of rechargeable battery is a lithium battery, which can include a lithium-ion or a lithium-polymer battery.
Lithium-polymer batteries often include cells that are packaged in flexible pouches. Such pouches are typically lightweight and inexpensive to manufacture. Moreover, these pouches may be tailored to various cell dimensions, allowing lithium-polymer batteries to be used in space-constrained portable electronic devices such as mobile phones, laptop computers, and/or digital cameras. For example, a lithium-polymer battery cell may achieve a packaging efficiency of 90-95% by enclosing rolled electrodes and electrolyte in an aluminized laminated pouch. Multiple pouches may then be placed side-by-side within a portable electronic device and electrically coupled in series and/or in parallel to form a battery for the portable electronic device.
Recent advances in battery technology have also led to the development of solid-state batteries, in which electrodes and a thin solid electrolyte are layered on top of a non-conducting substrate. Because the solid electrolyte takes up less space and/or weighs less than the liquid electrolyte of a comparable lithium-ion and/or lithium-polymer battery, the solid-state battery may have a higher energy density than the lithium-ion and/or lithium-polymer battery. In addition, the solid-state battery may be safer and/or more reliable than conventional lithium-ion and/or lithium-polymer batteries. For example, the use of a non-flammable, solid electrolyte in the solid-state battery may allow the solid-state battery to sidestep liquid electrolyte hazards such as spilling, boiling, gassing, and/or fires. Consequently, solid-state batteries may improve the safety, reliability, form factor, and/or runtime of portable electronic devices.

This patent is subject to a terminal disclaimer.

Charging techniques for solid-state batteries in portable electronic devices


In a known wavelength multiplexer, optical signals to pass are passed with their wavelengths held identical. Therefore, unless an unused wavelength common to all zones exists in case of setting an optical channel, the channel cannot be set. According to the present invention, a drop/add type wavelength multiplexer includes a wavelength converting section (50 in FIG. 5) which converts the wavelengths of optical signals to pass from the input side of the multiplexer to the output side thereof. In a network employing the wavelength multiplexers at individual nodes, a new optical channel can be easily set by utilizing wavelengths not used at the nodes.

The present invention relates to a wavelength multiplexing transmission method and an optical network in which a plurality of optical signals of different wavelengths are multiplexed and transmitted, and an optical transmission apparatus which can be used for the transmission method and the optical network.
Heretofore, a method as stated below has been known as an expedient for extending a ring network based on wavelength multiplexing technology. It is contained in, for example, Rajiv Ramanswasmi and Kumar N. Sivarajan: "Optical Networks—A Practical Perspective—" published by Morgan Kaufmann Publishers, page 449. A general construction for the method has been as shown in, for example, FIG. 10. 15 in the book. The method is founded on the construction that, in case of realizing a ring network of the type which drops or adds only specific wavelengths, optical signals of wavelengths propagating via a certain node apparatus are outputted at the same wavelengths as the inputted wavelengths. Accordingly, a practicable node apparatus is constructed including a dropping section in which any signals are derived from a wavelength demultiplexing unit located on the input side of the node apparatus and are outputted outside, and an adding section in which optical signals given from outside are connected to a wavelength multiplexing unit located on the output side of the node apparatus. Herein, the certain wavelength signals delivered from the wavelength demultiplexing unit are directly delivered to the wavelength multiplexing unit as the signals having the same wavelengths. Thus, the optical signals which are dropped or added by the apparatus itself are externally outputted or inputted via the dropping section or the adding section. On this occasion, the apparatus does not drop or add any wavelengths for itself, but it transmits the optical signals inputted for other apparatuses, from one side to the other side thereof without changing the wavelengths of the optical signals. Although the network of ring scheme (ring network) is exemplified here, a similar method is known also in a linear network. The "linear network" is a network architecture wherein node apparatuses are arrayed in one row, and wherein optical signals of any wavelengths are dropped or added by the node apparatuses arranged midway.
Next, a node apparatus for such a network will be concretely exemplified. FIG. 1 shows an example of the node apparatus which has a wavelength multiplexing function and which incarnates the dropping and adding of specific wavelengths. A wavelength dropping section includes a first space switching unit 1, a wavelength demultiplexing unit 3 and an interface unit 5 for input wavelength-multiplexed optical signal 7. The wavelength demultiplexing unit 3 demultiplexes the input wavelength-multiplexed optical signal 7 into individual wavelengths (λ1, λ2, λ3, . . . , λN), which are respectively delivered to predetermined transmission lines 9. The first space switching unit 1 drops optical signal of desired specific wavelengths in the input wavelength-multiplexed optical signal 7. The interface unit 5 outputs the dropped input lights as desired dropped optical signals. Thus, the wavelength dropping section demultiplexes the input wavelength-multiplexed optical signal 7 into the individual wavelengths and drops the desired wavelengths so as to output the dropped optical signals 12.
On the other hand, a wavelength adding section includes an interface unit 6, a second space switching unit 2 and a wavelength multiplexing unit 4 for output wavelength-multiplexed optical signal 8. The interface unit 6 outputs optical signals to-be-added 13. Optical signals 10 transmitted from the first space switching unit 1, and the optical signals to be-added 13 transmitted from the interface unit 6 are delivered to predetermined transmission lines 11 via the second space switching unit 2 in accordance with connection route settings for the optical signals respectively having the individual wavelengths. The optical signals 11 of the plurality of wavelengths (λ1, λ2, λ3, . . . , λN) thus delivered are wavelength-multiplexed by the output wavelength multiplexing unit 4, and the resulting optical signal is outputted as the wavelength-multiplexed optical signal 8. Here, each of the first space switching unit 1 and the second space-switching unit 2 is constructed of optical switches etc.
Apart from the above expedient in which the dropping or adding section is constructed of the optical switches, a wavelength multiplexer of drop/add type employing "Fiber Bragg Grating" technology has also been proposed. The drop/add type wavelength multiplexer is illustrated in, for example, FIG. 3. 60 on page 172 of the aforementioned book "Optical Networks—A Practical Perspective—". The fiber Bragg grating technology is optical filter technology which utilizes periodical refractive index modulation within an optical fiber as is formed when the optical fiber doped with Ge (germanium) is irradiated with the interference fringes of ultraviolet light. The construction of the drop/add type wavelength multiplexer employing the fiber Bragg grating technology is shown in FIG. 2. A light dropping section 20 includes a circulator 26 and a splitter 27. In the circulator 26, light propagating rightwards from left is totally transmitted, whereas light propagating leftwards from right is totally reflected downward to the splitter 27 as viewed in the figure. In fiber Bragg gratings 24, only lights of wavelengths λ1, λ2, λ3 and λ4 in the rightward light are totally reflected leftwards. A light adding section 22 includes a combiner 28 and a coupler 29. In the figure, numeral 7 indicates the input wavelength-multiplexed optical signal, and numeral 8 indicates the output wavelength-multiplexed optical signal.
With the fiber Bragg grating technology, the optical signals of the specific wavelengths are derived by a diffraction grating at an input stage in a state where the wavelengths are multiplexed as they are.
It is common to both the dropping/adding methods stated above that the wavelengths of optical signals which are transmitted remain unchanged.
A network wherein a plurality of node apparatuses of the type dropping and adding optical signals of specific wavelengths are connected, has a difficulty as explained below.
In the network wherein the plurality of apparatuses dropping and adding the optical signals of specific wavelengths are connected in a ring scheme or a linear scheme, a request for connecting an optical channel is generally made by designating any two of the plurality of apparatuses which constitute the whole network. In that case, regarding which of wavelengths is to be used for the connection, a wavelength not used in any zone is selected in accordance with the situation of uses of the wavelengths in all zones. Various algorithms corresponding to the individual aspects of uses have been proposed for the selection. Typical examples of the algorithms are as follows: The first example is a method wherein fixed Nos. denoted by natural numbers are assigned to wavelengths usually applied, and wherein an unused wavelength is selected from the smaller one of the Nos. The second example is a method wherein any wavelength is selected from among unused wavelengths by employing a random number.
In an actual transmission circuit, however, a problem is posed as stated below. In general, requests for channels to be connected are not fully determined at the time of the construction of the network. Accordingly, the optical channels of the transmission circuit are added or deleted in accordance with the requests for channels arising every day, and the settings of the channels need to be altered in correspondence with the addition or deletion of the optical channels.
With the prior-art technique mentioned above, it is required to select the wavelength which is not used in any of all the zones of the channel. Accordingly, when a request for connection has occurred in a certain channel, a wavelength which is not used in any of the zones included from a certain apparatus to another apparatus must be selected. In the nonexistence of such a wavelength, the optical transmission channel requested to be connected cannot be connected in spite of the existence of unused wavelengths in the individual zones.
This state is shown in FIG. 3. The figure exemplifies an optical network in the case where node apparatuses A–E, i.e. five apparatuses 100, 101, 102, 103 and 104 are connected in one row. Letters a, b, c, . . . and h indicate channels which are respectively connected to the node apparatuses. The respectively adjacent apparatuses are connected by a multiplex channel of four wavelengths. That is, the multiplex channel can accommodate, up to, four optical channels. Incidentally, the case of the four wavelengths is mentioned here, but in general, the number of wavelengths is not especially restricted. Besides, although the node apparatuses are connected in one row in the example of FIG. 3, the same holds true even when node apparatuses are connected in a ring shape or in a mesh shape. Further, the algorithm of minimum value selection as is the simplest algorithm shall be adopted here. Also, a request for a channel shall be an additional request in the ensuing description.
It is now assumed that requests for connections have occurred in the order of the channels a, b, c, d, . . . and g. Then, the wavelengths of the smallest Nos. usable in compliance with the requests for the connections of the channels are selected on the basis of the algorithm of the minimum value selection. Thus, the seven channels from the channel a to the channel g are set as shown in FIG. 3. By way of example, the channel a connects the node apparatuses A and B, and the wavelength of wavelength No. 1 is used for the channel. The connections of the other channels are similarly understood. Here, it must be attended to that, in the case of the method which uses the same wavelengths in all the channels connected, each of the node apparatuses outputs the same wavelengths as the inputted wavelengths.
It is now considered that the request for the connection of the channel h has been further added. The channel h corresponds to the request for the connection from the node apparatus B to the node apparatus E. When the situation of uses of the wavelengths in the node apparatus C is viewed here, wavelength Nos. 3 and 4 are already used on the left side (on the side of the node apparatus B), and wavelength Nos. 1 and 2 are already used on the right side (on the side of the node apparatus E). Consequently, any wavelength usable on both the right and left sides in common does not exist in the node apparatus C. Accordingly, this example involves the problem that the channel h cannot be added though the node apparatus although C has the unused wavelengths on both the right and left sides. For adding the channel h, therefore, it is necessary to build, for example, another network of ring scheme constituted by a plurality of similar apparatuses. This means that a wavelength multiplexing capability is not fully exploited in the multiplex system of wavelength multiplexing.

Optical multiple transmission method, optical network and optical transmission apparatus


A method for performing a fibre channel arbitrated loop integrity test using a fibre channel switch element is provided. The method includes, sending a fibre channel frame through the arbitrated loop; receiving the fibre channel frame after it has traversed through the arbitrated loop; performing a data compare between the fibre channel frame that was sent and the fibre channel frame that is received; detecting internal errors, if any, in the traversed fibre channel loop; and isolating a module that may have generated the error. The switch element includes, a cascade port that is used to couple one fibre channel switch element to another in a loop; and a port that sends a fibre channel frame through the loop and detects internal errors based on the comparison and a isolates a module that may have generated the internal error.

1. Field of the Invention
The present invention relates to networks, and more particularly to performing loop pathway integrity checks in a fibre channel arbitrated loop topology.
2. Background of the Invention
Fibre channel is a set of American National Standard Institute (ANSI) standards, which provide a serial transmission protocol for storage and network protocols such as HIPPI, SCSI, IP, ATM and others. Fibre channel provides an input/output interface to meet the requirements of both channel and network users.
Fibre channel supports three different topologies: point-to-point, arbitrated loop and fibre channel fabric. The point-to-point topology attaches two devices directly. The arbitrated loop topology attaches devices in a loop. The fibre channel fabric topology attaches host systems directly to a fabric, which are then connected to multiple devices. The fibre channel fabric topology allows several media types to be interconnected.
Fibre channel is a closed system that relies on multiple ports to exchange information on attributes and characteristics to determine if the ports can operate together. If the ports can work together, they define the criteria under which they communicate.
In fibre channel, a path is established between two nodes where the path's primary task is to transport data from one point to another at high speed with low latency, performing only simple error detection in hardware.
FC-AL is one fibre channel standard (incorporated herein by reference in its entirety) that establishes the protocols for an arbitrated loop topology. In a conventional FC-AL implementation there can be as many as 128 ports on the FC-AL loop. The data path consists of several transmit and receive paths.
During normal loop operation when Fibre Channel devices are connected, internal data path error, external data path error or interconnection error can cause a failure. Conventional systems do not have testing methods that isolate internal failure from an external failure or interconnection failure. A device causing a failure cannot be isolated using parity checking alone, other more robust testing methods like a CRC check are needed
Conventional fabric elements in a FC-AL topology are not robust and do not provide an efficient way to identify, isolate and manage loop traffic.
One such problem is shown in system 210 of FIG. 2B. System 210 includes a fibre channel element (or a switch) 216 that couples host systems 213-215 to storage systems 217 and 218. Storage system 217 and 218 include redundant array of independent disks (RAID) 211 coupled via plural input/output ("I/O") modules and RAID controllers 201A and 201B. If drive 219 is defective, it may disrupt all traffic in common-access network 220. This can result in loop failure and lower performance of the overall network.
Another example is shown in FIG. 2A, where a RAID controller 201 is coupled to two different loops 209A and 208A via links 209 and 208 in a disk array system 200. Each loop has a small computer systems interface (SCSI) enclosure services ("SES") module 202 and 202A. SES modules 202 and 202A comply with the SES industry standard that is incorporated herein by reference in its entirety.
Port bypass controller ("PBC") modules 203 (and 206) couple plural disks (for example, 204, 202B and 207) and link 205 couples the PBC modules.
If drive 202B, which is dual ported, fails then both loops 209A and 208A are disrupted. Again, conventional techniques will require that storage 202A be removed and a bypass command issued to all drives, which takes the entire array off-line. Each device is attached and detached to investigate the reason for a link failure. Then all the drives, except the faulty drive are re-attached and loop activity is restored. This system of trial and error is labor intensive and inefficient.
Another drawback in conventional Fibre Channel networks is that loop functional test patterns and automatic test pattern generators ("ATPG") are used to check individual L_PORTS. Conventional systems do not provide any tests that can check the entire FC-AL loop integrity. Also, there are no pattern generators that can generate an actual Fibre Channel frame with the correct encoding and disparity, consisting of a SOF, Header, Payload, correct Fibre Channel CRC, and EOF to check individual port integrity. Furthermore, de-bugging is performed on a trial and error basis when any failure occurs. Failures are debugged on a board one port at a time, which is tedious and time consuming and hence commercially undesirable.
Therefore, there is a need for a method and system for efficiently detecting FC-AL integrity.

Method and apparatus for testing loop pathway integrity in a fibre channel arbitrated loop


A jumper is for an electrical switching apparatus having a plurality of poles. Each of the poles comprises a terminal. The terminal of a first one of the poles is proximate the terminal of a second one of the poles. The jumper includes a jumper member having an attachment portion and a heat sink portion. The attachment portion is structured to electrically connect the terminal of the first one of the poles to the terminal of the second one of the poles. The heat sink portion includes a plurality of spaced apart heat transfer members that are arranged in a plurality of rows and a plurality of columns.

Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to circuit interrupters, such as, for example, circuit breakers. The disclosed concept also relates to jumpers for electrical switching apparatus. The disclosed concept further relates to methods of making jumpers.
Background Information
Circuit breakers are typically available in one-, two-, three- and four-pole construction, although larger counts of poles are possible. It is known to connect multiple poles of circuit breakers in series to provide a high voltage for a low voltage switching and interruption device (e.g., without limitation, 750 VDC; 1000 VDC; 1500 VAC). For a 1000 VDC application, for example, typically multiple circuit breakers are electrically tied together. Most known existing six-pole or eight-pole air circuit breakers are designed such that the poles are electrically connected internally in breaker structures in a predetermined manner.
It is known that to obtain higher interruption and voltage ratings, circuit breaker poles can be wired in series. Normally, cable or bus bars are electrically connected to the circuit breaker terminals, which carry the current and remove a significant amount of the heat that is generated within the breaker. A conventional shorting strap, commonly referred to as a jumper, electrically connected between poles can carry the current, but does not remove much heat, resulting in relatively high temperature rises at the circuit breaker terminals. Commonly assigned United States Patent Application Publication No. 2013/0213780 discloses an example jumper for electrically connecting electrical switching apparatus poles.
Consumer markets demand a circuit breaker jumper that both occupies relatively little space and operates at relatively low temperatures. The conventional tradeoff in jumper design, however, is between size and thermal performance (e.g., heat transfer). That is, to achieve lower operating temperatures, typically the size of the jumper must increase, and vice versa. Stated another way, jumper designs must generally concede in one of these areas, or otherwise be cost-prohibitive.
There is room, therefore, for improvement in electrical switching apparatus, such as circuit breakers, and in jumpers and associated methods therefor.

Electrical switching apparatus, and jumper and associated method therefor


A first object of the present invention is to provide Co-based alloys for biomedical applications which are Ni-free, high intensity and high elastic modulus and are suitable for plastic workability. Moreover, a second object of the present invention is to provide Co-based alloys for biomedical applications having X-ray visibility. Furthermore, a third object of the present invention is to provide a stent using the alloys. The Co-based alloys for biomedical applications according to the present invention is configured by adding alloy elements having biocompatibility and an effect of increasing stacking fault energy of the alloys.

1. Field of the Invention
The present invention relates to Co-based alloys for biomedical applications and in particular, to Co-based alloys for biomedical applications which are suitably provided for use of medical equipment such as equipment embedded-in a living body and equipment which has contact with the living body. In addition, the present invention relates to a stent.
2. Description of the Related Art
For alloys which are used for medical equipment embedded-in a living body or for medical equipment used while being in direct contact with the surface of the living body, high corrosion resistance and biocompatibility are required. Furthermore, with respect to alloys for a stent for securing blood flow by expanding coarctation site of a blood vessel within a living body, high intensity and high elastic modulus are required.
As Co-based alloys for biomedical applications which satisfy such requirements described above, alloys which consist primarily of Co-20 Cr-15W-10Ni (ASTM standard F90), alloys which contain the following, Co: 30% to 60%, Ni: 4% to 20%, Cr: 13% to 25%, C: equal to or less than 0.3%, Si: equal to or less than 2.0% and Mn: equal to or less than 2.0% or the like are well known (refer to PTL 1).    Patent Literature: [PTL 1] JP-A-2007-162121

Co-based alloys for biomedical applications and stent


There is provided a method of dyeing cellulosic and/or wool fibers and fabrics in a dyebath containing a dilute solution of tannic acid and/or tannic acid containing products at a proper pH. An exhaust salt is added to the bath to exhaust the tannic acid and then the tannic acid is fixed with an iron salt.

It has been known that basic dyes can be fixed onto cotton by making use of a tannin mordant. The usual mordant comprises tannic acid that has been insolubilized with tarter emetic (basic antimony oxide). The resulting antimony tannate is employed to fix a basic dye onto the cellulose (which is thought to be as an insoluble color lake). In the mordanting process the water utilized must be absolutely free of any iron or the shades are adversely affected, being duller as the result of the reaction of the tannin to form black complexes (See for example J.M. Matthew's, Application of Dyestuffs to Textiles, Paper, Leather and Other Materials, Wiley, 1920).
The prior process for mordanting of textile goods, specifically cotton cellulose is not presently being employed because the antimony salts are highly poisonous in nature and therefore have ecological concerns for the environment. The treated fabrics needed to be rigorously washed in order to remove any unfixed antimony otherwise blood poisoning could result when the fabrics were worn next to the skin. Again antimony salts in the wash effluent gives rise to environmental concerns.
Today's consumers are quite aware of the environment and the problems that are associated with the coloration of textiles with synthetic dyestuffs. There appears to be a genuine desire on the part of the consumer to obtain textiles that have their coloration obtained with natural and/or non polluting dyeing materials, methods and procedures.
At the present time, sulfur dyes are primarily utilized to obtain a black color on cellulosic goods. C.I. Sulfur Black 1 is one of the most widely used dyes in the world for this purpose. Sulfur dyes are intrinsically insoluble, but they dissolve in solutions of alkaline reducing agents from which they are substantive to cellulosic materials. Once on the fiber, they must be converted back to their insoluble pigmentary form by oxidation.
Some of the problems with sulfur dyed goods is a phenomena known as bronzing as well as acid tendering. In severe conditions of heat and humidity or with improper oxidation, some sulfur dyeings, notably black, can generate a small amount of sulfuric acid within cellulosic fibers leading to tendering.


The present invention provides a method of manufacturing n battery cells (n≥2), each including a respective reference electrode for measuring a relative electrode potential, including: (i) manufacturing a reference cell composed of an electrolyte solution, the reference electrodes, and a lithium electrode; (ii) charging the reference cell; (iii) charging the reference cell to 40% to 60% of a capacity discharged in the process (ii), thereby performing formation on the reference electrodes; (iv) manufacturing the n battery cells, each of the battery cells including a respective one of the reference electrodes, an electrode assembly, the electrolyte solution and a battery case; and (v) in each of the battery cells, measuring a relative potential of the respective one of the reference electrodes and a positive electrode of the respective electrode assembly, and a relative potential of the respective one of the reference electrodes and a negative electrode of the respective electrode assembly.

As the technology development and demand for mobile devices are increased, demand for rechargeable batteries as an energy source is rapidly growing, and accordingly, a lot of research on a rechargeable battery cell satisfying various needs is being conducted.
Particularly, demand for a lithium rechargeable battery cell such as a lithium ion battery and a lithium ion polymer battery, having merits such as high energy density, discharge voltage and output stability is high.
Meanwhile, an electrode potential of a battery is measured for developing a new battery cell, and confirming performance of the manufactured battery cell.
For measuring an electrode potential, a method of measuring an electrode potential in a three-electrode system composed of a reference electrode, a working electrode, and a potential electrode is mainly used.
The reference electrode is an electrode which is, for measuring the potential of an electrode forming a battery or an electrode where electrolysis occurs, used in manufacturing a battery circuit for electrode potential measurement in combination, and is used as a potential standard when measuring a relative value of an electrode potential.
This reference electrode should satisfy the requirements such as following the Nernst equilibrium equation as a reversible electrode potential (an electrode in a reversible state), having a nonpolarizing characteristic to maintain a constant potential value at all time, having as little liquid potential difference as possible, having a small potential change even with a temperature change, and representing a constant potential value at a constant temperature.
One reference electrode is combined per a battery cell, for measuring an electrode potential, and in order to increase reliability of the reference electrode, a process of activating the reference electrode to have a plateau potential having no change in the potential due to charging and discharging is carried out.
This activation process is generally to apply a microcurrent to the reference electrode and a positive electrode of the battery cell to repeatedly charge and discharge the battery cell, while performing formation of a plateau section ('a plateau potential') where the reference electrode has a constant electrode potential.
However, this activation process is to estimate the potential or plateau potential of the reference electrode with a potential difference between the positive electrode of a battery cell and the reference electrode, and the potential may be different from the actual potential of the reference electrode, or the potential of the activated reference electrode may not actually be the plateau potential.
As such, in the case that the potential of the reference electrode is inaccurate, or the potential of the positive and negative electrodes of the battery cell is measured in the state of a non-plateau potential, the measured potential may be different from the actual potential of the positive and negative electrodes, and thus, the measurement method of the potential using the reference electrode is difficult to be reliable.
Furthermore, a trace amount of lithium migrates from a positive electrode to a reference electrode in the course of activation, and then the electrode capacity of the positive electrode may be finely decreased by the lost lithium ions in the positive electrode.
Besides, in the case that the battery cells are produced in large quantities, the activation process should be performed after one reference electrode is combined per one battery cell, and thus, the manufacturing process of the battery cells takes a long time.
Accordingly, there is currently a high need for technique allowing the activation process of the reference electrode to be easily performed, and accurate measurement of the electrode potential of the reference electrode, and through this reference electrode, enabling highly reliable measurement of the electrode potential of the battery cell.

Method of manufacturing battery cell including reference electrode for measuring relative electrode potential, and battery cell manufactured therefrom


A method of monitoring a patient for seizure activity may include monitoring the patient by collecting an electromyography signal, determining features of the signal using wavelet analysis and inputting determined feature values into a neural network trained to detect seizure activity. Related apparatuses are also described.

A seizure may be characterized as abnormal or excessive synchronous activity in the brain. At the beginning of a seizure, neurons in the brain may begin to fire at a particular location. As the seizure progresses, this firing of neurons may spread across the brain, and in some cases, many areas of the brain may become engulfed in this activity. Seizure activity in the brain may cause the brain to send electrical signals through the peripheral nervous system activating different muscles of the body.
Techniques designed for studying and monitoring seizures have typically relied upon electroencephalography (EEG), which characterizes electrical signals using electrodes attached to the scalp or head region of a seizure prone individual or seizure patient. In EEG, electrodes may be positioned so as to measure such activity; that is, electrical activity originating from neuronal tissue. Alternatively, electromyography (EMG) may be used for seizure detection. In EMG, an electrode may be placed on or near the skin, over a muscle, to detect electrical activity resulting from muscle fiber activation.
Detecting signals using EEG typically requires attaching many electrodes and associated wires to the head and using amplifiers to monitor brainwave activity. The multiple EEG electrodes may be very cumbersome and generally require some technical expertise to apply and monitor. Furthermore, confirming a seizure requires observation in an environment provided with video monitors and video recording equipment. Unless used in a staffed clinical environment, such equipment may not be intended to determine if a seizure is in progress, but rather to provide a historical record of the seizure after the incident. Such equipment is usually meant for hospital-like environments where a video camera recording or caregiver's observation may provide corroboration of the seizure, and is typically used as part of a more intensive care regimen such as a hospital stay for patients who experience multiple seizures. Upon discharge from the hospital, a patient may be sent home often with little further monitoring.
Ambulatory devices for diagnosis of seizures are generally EEG-based, but because of the above shortcomings those devices are not designed or suitable for long-term home use or daily wearability. Other seizure alerting systems may operate by detecting motion of the body, usually the extremities. Such systems may generally operate on the assumption that while suffering a seizure, a person will move erratically and violently. For example, motion sensors such as accelerometers may be used to detect violent extremity movements. However, depending upon the type of seizure, this assumption may or may not be true. Electrical signals sent from the brain during some seizures may be transmitted to many muscles simultaneously, which may result in muscles fighting each other and effectively canceling out violent movement. In other words, the muscles may work to make the person rigid rather than cause actual violent movement. Thus, some seizures may not be consistently detected with motion-based sensors such as accelerometer-based detectors.
Ambulatory devices for diagnosis of seizures are generally not suited to grade seizures based on intensity, nor are they suited to differentiate seizure-related signals based on event type. Rather, different types of seizures may often be grouped together. Accordingly, ambulatory devices for seizure detection may be ill-suited to customize responses for different types of detected seizure events. However, not all seizures or seizure-related events may necessarily demand the same response. For example, at least for some patients or some patients in certain situations, seizure events may be detected and the event recorded, but without automatic initiation of a complete and costly emergency response. Thus, other ambulatory devices are not ideally suited for cost-effective monitoring of some patients. Also, using current ambulatory devices, caregivers may mis-diagnose some conditions, including some that may benefit from condition-specific therapies. For example, some events, such as psychogenic or non-epileptic seizure events, may be grouped together with generalized tonic-clonic seizure events. Statistical analysis of event signals may encourage effective diagnosis of some commonly mis-diagnosed conditions. However, other ambulatory detection systems are generally not configured to provide organized statistical information to caregivers as may be used to medically or surgically manage a patient's care.
Accordingly, there is a need for detection methods and apparatuses suitable to identify abnormal brain activity such as may be related to seizure activity and that can be used in non-institutional or institutional environments without many of the cumbersome electrodes to the head or extremities. There is further a need for detection methods that are suited to grade seizures by type and/or intensity and customize alarms so as to provide robust and cost effective patient care. There is also a need for monitoring systems that organize medical data within databases to help medically and surgically manage patient care.

Method and apparatus for detecting and classifying seizure activity


A transceiver as provided for effectively multiplexing IDE address and data lines with selected ISA address and data lines. Compatibility among the IDE data transfers and ISA functions are achieved by multiplexing the ISA lines that do not involve the ISA refresh of the ISA expanded memory. The transceiver includes an enable input that, when disabled, effectively isolates the IDE data lines from the ISA bus so that IDE data transfers can occur. When the enable input is active, the ISA lines not related to refresh are connected to the IDE data lines so that ISA operations can occur. Furthermore, a directional input is included in the transceiver for allowing a central processing unit to control the ISA when the directional input is active and for allowing a PCI/ISA bridge between the PCI bus and the ISA bus to control the ISA operations included the multiplexing. The result is a rearrangement of the IDE data lines with the ISA bus to eliminate a multitude of pins and connectors.

1. Field of the Invention
The present invention relates to data processing systems and, more particularly, to devices used to interface internal components of a microprocessor-based system.
2. Description of Related Art
Conventional computer systems generally include one or more central processing units (CPU's) providing primary controls of the computer system. These CPUs are connected through a host bus to a Host/PCI bus bridge that interfaces among the CPU, the main memory and the peripheral components. The Host/PCI bridge is connected to a peripheral component interface (PCI) bus, which is connected to peripheral components such as local area networks, graphics cards and mass media devices.
Also included in conventional systems is a PCI/ISA bridge that interfaces the PCI bus with an industry standard architecture (ISA) bus. The ISA bus interfaces with peripheral devices such as hard drives, CD ROMs, keyboard input, mouse input, etc. Mass storage components are serviced by the ISA bus and are accessible by the CPU through the PCI/ISA bridge. These peripheral components are much slower than components connected to the PCI bus. Components on the PCI bus usually operate at an optimum 33 MHz, where components on the ISA bus typically run at 8 MHz. Therefore, the bridge acts as a PCI/ISA bridge so that the slower peripheral components serviced by the ISA bus are made compatible with the main system.
In a typical data transfer sequence from the mass storage devices, a CPU sends an Integrated Device Electronics (IDE) data transfer command through the host bus which in turn sends the command through the host/PCI bus bridge to the PCI bus. From there, the PCI bus sends a command through the PCI/ISA bridge. The PCI/ISA bridge then takes over the IDE data transfer operations. The command from the CPU programs the PCI/ISA bridge to carry out the IDE data transfer operation through predetermined procedures. The PCI/ISA bridge is connected to an IDE circuitry that interfaces the mass storage devices such as hard drives, CD ROMs, tape backups, etc. The IDE circuitry is connected to the traditional computer hard drive through a ribbon cable. In conventional systems, more than one set of IDE circuitry can exist so that the system has access to multiple mass storage devices. In an IDE data transfer cycle, the PCI/ISA bridge accesses the IDE circuitry through a series of data lines that access the mass storage devices through the IDE circuitry. Typically, separate pins of the PCI/ISA bridge are used to transfer this data.
Aside from access to peripheral devices, the ISA bus also includes an ISA expansion memory that requires refresh. During refresh, the entire ISA bus is taken out of operation so that the refresh cycles can commence. During these cycles, typically once every 15 .mu.s, or 1/15 of the total operating time, no functions can be executed on the ISA bus.
Optimization of a computer system as a whole requires that communication lines and connectors be kept to a minimum in order to maintain speed, efficiency, simplicity and manufacturability. One way of optimizing a computer system is to multiplex lines to share paths and connections. Both the IDE circuitry and the ISA bus require multitudes of paths and connections including data, address and control lines. A great deal of circuitry and space could be saved if nonconflicting portions of these two systems could be multiplexed. Unfortunately, conventional methods cannot accomplish this without stopping IDE data transfers during ISA refresh cycles.
Accordingly, it would be of great use to the computer industry to successfully multiplex portions of the IDE circuitry with nonconflicting portions of the ISA bus. As will be seen, the present invention accomplishes this in a simple and elegant manner.

Apparatus and method for multiplexing integrated device electronics circuitry with an industry standard architecture bus


A pneumatically dithered ring laser gyroscope features providing an oscillatory motion directly to a segment of the excited gas which serves as the laser photon source. Alternately switching ionizing potential between two cathodes in appropriately designed cavities establishes desired oscillatory gas velocities to effect emitted frequencies within the gyro, thereby permitting the detection of rotational rates below the "lock-in" rate of the undithered gyro.

This invention relates generally to ring laser gyroscopes (gyros) and more particularly to ring laser gyros which are dithered to reduce the effects of mode locking otherwise referred to as "lock-in."
Ring laser gyroscopes feature a pair of light beams which are counterpropagated around a closed loop path. The two counterpropagating light beams are compared in frequency. When the gyro rotates in inertial space, the two counterpropagating beams see apparently unequal paths. This causes the beams to resonate at two different frequencies. The frequency difference is measured to provide an indication of the direction and rate of rotation of the gyro.
For small rotational rates a phenomenon referred to as mode or frequency locking or "lock-in" occurs. The frequencies of the two counterpropagating light beams lock to each other and the beams resonate together. This creates a dead zone for which no useful gyro output is obtained.
Various arrangements have been employed to avoid or reduce the lock-in phenomenon. One such arrangement features mechanical dithering of the gyro. The entire gyro is mechanically oscillated at a relatively high frequency. This gives the gyro a dynamically varying bias rotation rate which exceeds the threshold input rate or natural lock-in rate of the dead zone. While a mechanical arrangement of the type described accomplishes the desired results, it adds undesirable energy consumption, cost, weight, size and complexity to a system, such as an attitude reference system, employing the gyro. Mechanical dithering also introduces an undesirable source of vibration and noise into the system which may cause problems in the use of other instruments such as accelerometers or the like which are mounted with the gyro in the system.
Optical devices have been inserted into the laser cavities to introduce a bias or asymmetry into the operation of the laser to avoid the aforenoted mode locking. However, a problem arises in the optical approach in that the optical elements increase the number of interfaces between dissimilar materials in the optical path. Each interface tends to be a source of increased light scattering so that the mode locking effect which the optical devices attempt to reduce is actually enhanced. Further, the optical elements themselves, which may include Faraday cells or other like devices, introduce bias errors into the operation of the gyro due to such factors as, for example, asymmetry and random variations in their characteristics due, for example, to temperature variations.
Electrical excitation, or pumping power, for lasing is typically applied to the laser gaseous medium from a direct current supply. A voltage sufficient to sustain a discharge in the medium is applied to electrodes arranged in spaced relation. The discharge, or plasma excitation current, includes a flow of ionized gas between oppositely polarized electrodes in the optical cavity. This plasma flow tends to induce a bias in a ring laser gyro. Therefore, ring laser gyros using direct current excitation typically include a balanced electrode structure wherein two electrodes of one polarity are symmetrically disposed about a single electrode of the opposite polarity. With the arrangement described, two equal and opposite plasma excitation currents are caused to flow and their biases are thereby caused to cancel. The electrical excitation to sustain the plasma excitation currents may be obtained from the supply which varies the voltage so as to dynamically unbalance the currents. A dynamically varying bias in a gyro output, i.e. a dither, may thereby be induced. However, the maximum amount of dither obtainable in this way is too small to be given any practical consideration.
Other dithering schemes have been attempted. One such scheme involves pumping the plasma more vigorously. A linear induction motor is positioned adjacent the laser gain section and pumps the ionized gas unidirectionally. The apparent index of refraction for the counterpropagating light beams is therefore made different by an amount sufficient to avoid mode locking. This arrangement uses large amounts of energy and the requirement for an electromagnetic structure increases the weight of the system. Additionally, in a scheme such as described where a unidirectional bias is induced, no cancellation of systematic errors occurs.
U.S. Pat. No. 4,325,033 issued to Shutt on Apr. 13, 1982 and assigned to Rockwell International Corporation attempts to avoid the disadvantages of the aforenoted dithering schemes. The patented arrangement features a mechanically dithered ring laser gyro in which the effects of mode locking at low rotation rates are reduced by providing an oscillatory flow of the ionized gas in the gain section of the laser. The structure involved features an envelope in which the laser is sealed and includes a pair of closed-end bellows. The bellows are extended and retracted in push-pull relationship to pump the gas so as to create a dynamically varying pressure differential and hence oscillatory gas flow along the bore of the gain section of the laser which induces a corresponding oscillatory bias in the gyro output. Here again, the bellows arrangement adds weight and size to a system using a ring laser gyro and is prone to intolerable inaccuracies for many applications.
The present invention avoids the aforenoted problems by pneumatically establishing an oscillatory motion directly to a segment of the excited gas which serves as the photon source. Alternately switching ionizing potential between two cathodes in appropriately designed cavities establishes the desired oscillatory gas velocities for effecting the emitted frequencies within the gyro thereby permitting the detection of rotational rates below the "lock-in rate" of the otherwise undithered gyro.

Pneumatically dithered ring laser gyroscope