Showing papers by "General Electric published in 2000"

Theory and applications of hazard plotting for censored failure data

Abstract: This paper presents theory and applications of a simple graphical method, called hazard plotting, for the analysis of multiply censored life data consisting of failure times of failed units intermixed with running times on unfailed units. Applications of the method are given for multiply censored data on service life of equipment, for strength data on an item with different failure modes, and for biological data multiply censored on both sides from paired comparisons. Theory for the hazard plotting method, which is based on the hazard function of a distribution, is developed from the properties of order statistics from Type II multiply censored samples.

System and method for managing a fleet of remote assets

Abstract: Method and system for managing a plurality of remote assets, such as a fleet mobile assets is provided. The method allows for collecting data regarding each of a plurality of remote assets. The collected data is used to develop historical information regarding actual usage of each remote asset. The information is distributed via a global information network.

Safety of Strong, Static Magnetic Fields

Abstract: Issues associated with the exposure of patients to strong, static magnetic fields during magnetic resonance imaging (MRI) are reviewed and discussed. The history of human exposure to magnetic fields is reviewed, and the contradictory nature of the literature regarding effects on human health is described. In the absence of ferromagnetic foreign bodies, there is no replicated scientific study showing a health hazard associated with magnetic field exposure and no evidence for hazards associated with cumulative exposure to these fields. The very high degree of patient safety in strong magnetic fields is attributed to the small value of the magnetic susceptibility of human tissues and to the lack of ferromagnetic components in these tissues. The wide range of susceptibility values between magnetic materials and human tissues is shown to lead to qualitatively differing behaviors of these materials when they are exposed to magnetic fields. Mathematical expressions are provided for the calculation of forces and torques.

Bioaugmentation for Accelerated In Situ Anaerobic Bioremediation

Abstract: A successful anaerobic bioaugmentation was carried out on a trichloroethene (TCE)-contaminated aquifer at Dover Air Force Base, DE, using a microbial enrichment culture capable of dechlorinating TCE to ethene. A hydraulically controlled pilot system 12 × 18 m was constructed 15 m below ground surface in an alluvial aquifer to introduce nutrients and substrate into the groundwater. Ambient TCE and cis-1,2-dichloroethene (cDCE) concentrations in groundwater averaged 4800 and 1200 μg/L. The pilot operated for 568 days. Results by day 269 confirmed previous laboratory work showing that dechlorination did not proceed past cDCE. By this time, most of the TCE was dechlorinated to cDCE, and cDCE was the predominant contaminant. An ethene-forming microbial enrichment culture from the Department of Energy's Pinellas site in Largo, FL, was injected into the pilot area. After a lag period of about 90 days, vinyl chloride and ethene began to appear in wells. The injected culture survived and was transported through th...

Highly reliable power line communications system

Abstract: An electric power line communication system (20) operates with an electric power distribution system to provide through premises power distribution lines (28) highly reliable communication links among receiving devices (26, 32, 40, 46, 68, 112) electrically coupled orlocated in proximity to the premises power distribution lines. A power line transceiver (22,30, 34) is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The powerline transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Diagnosis and repair system and method

Abstract: A diagnosis and repair recommendation system for a railroad locomotive is disclosed. The system uses generalized repair recommendations and instantiates them to a specific repair process for a unique road number locomotive. In addition to repair steps to be executed by the technician, the method and system remotely provides supporting documentation specifically tailored for each step in the repair process. As the repair is being conducted, feedback information is entered by the technician. The repair recommendations and the supporting documents are available to the technician via a remote unit, thereby allowing the technician to access the repair steps and supporting documentation while the repair is in progress.

Fully embedded board-level guided-wave optoelectronic interconnects

Abstract: A fully embedded board-level guided-wave optical interconnection is presented to solve the packaging compatibility problem. All elements involved in providing high-speed optical communications within one board are demonstrated. Experimental results on a 12-channel linear array of thin-film polyimide waveguides, vertical-cavity surface-emitting lasers (VCSELs) (42 /spl mu/m), and silicon MSM photodetectors (10 /spl mu/m) suitable for a fully embedded implementation are provided. Two types of waveguide couplers, titled gratings and 45/spl deg/ total internal reflection mirrors, are fabricated within the polyimide waveguides. Thirty-five to near 100% coupling efficiencies are experimentally confirmed. By doing so, all the real estate of the PC board surface are occupied by electronics, and therefore one only observes the performance enhancement due to the employment of optical interconnection but does not worry about the interface problem between electronic and optoelectronic components unlike conventional approaches. A high speed 1-48 optical clock signal distribution network for Cray T-90 super computer is demonstrated. A waveguide propagation loss of 0.21 dB/cm at 850 nm was experimentally confirmed for the 1-48 clock signal distribution and for point-to-point interconnects. The feasibility of using polyimide as the interlayer dielectric material to form hybrid three-dimensional interconnects is also demonstrated. Finally, a waveguide bus architecture is presented, which provides a realistic bidirectional broadcasting transmission of optical signals. Such a structure is equivalent to such IEEE standard bus protocols as VME bus and FutureBus.

Very selective suppression pulses for clinical MRSI studies of brain and prostate cancer.

Abstract: Focal three-dimensional magnetic resonance spectroscopic imaging (3D MRSI) methods based on conventional point resolved spectroscopy (PRESS) localization are compromised by the geometric restrictions in volume prescription and by chemical shift registration errors. Outer volume saturation (OVS) pulses have been applied to address the geometric limits, but conventional OVS pulses do little to overcome chemical shift registration error, are not particularly selective, and often leave substantial signals that can degrade the spectra of interest. In this paper, an optimized sequence of quadratic phase pulses is introduced to provide very selective spatial suppression with improved B1 and T1 insensitivity. This method was then validated in volunteer studies and in clinical 3D MRSI exams of brain tumors and prostate cancer.

Solid state illumination system containing a light emitting diode, a light scattering material and a luminescent material

Abstract: A lamp containing a radiation source, a luminescent material and a radiation scattering material located between the radiation source and the luminescent material is provided. The lamp may be a white emitting lamp. The radiation source may be a blue emitting LED. The luminescent material may be a yellow emitting phosphor or dye. The radiation scattering material may be ceramic particles, such as TiO 2 particles, in a carrier medium, such as glass, epoxy or silicone.

GPS GDOP metric

Abstract: The authors present a review of the GDOP metric as used in GPS. Their goal is to review this metric and many of its known bounds as well as to report some new results. They use a formal linear algebraic framework to aid further study and insight.

Review of patient safety in time-varying gradient fields.

Abstract: In magnetic resonance, time-varying gradient magnetic fields (dB/dt) may stimulate nerves or muscles by inducing electric fields in patients. Models predicted mean peripheral nerve and cardiac stimulation thresholds. For gradient ramp durations of less than a few milliseconds, mean peripheral nerve stimulation is a safe indicator of high dB/dt. At sufficient amplitudes, peripheral nerve stimulation is perceptible (i.e., tingling or tapping sensations). Magnetic fields from simultaneous gradient axes combine almost as a vector sum to produce stimulation. Patients may become uncomfortable at amplitudes 50%-100% above perception thresholds. In dogs, respiratory stimulation has been induced at about 300% of mean peripheral nerve thresholds. Cardiac stimulation has been induced in dogs by small gradient coils at thresholds near Reilly's predictions. Cardiac stimulation required nearly 80 times the energy needed to produce nerve stimulation in dogs. Nerve and cardiac stimulation thresholds for dogs were unaffected by 1.5-T magnetic fields.

O(N/sup 2/log/sub 2/N) filtered backprojection reconstruction algorithm for tomography

Abstract: We present a new fast reconstruction algorithm for parallel beam tomography. The new algorithm is an accelerated version of the standard filtered backprojection (FBP) reconstruction, and uses a hierarchical decomposition of the backprojection operation to reduce the computational cost from O(N/sup 3/) to O(N/sup 2/log/sub 2/N). We discuss the choice of the various parameters that affect the behavior of the algorithm, and present numerical studies that demonstrate the cost versus distortion tradeoff. Comparisons with Fourier reconstruction algorithms and a multilevel inversion algorithm by Brandt et al., both of which also have O(N/sup 2/log/sub 2/N) cost, suggest that the proposed hierarchical scheme has a superior cost versus distortion performance. It offers RMS reconstruction errors comparable to the FBP with considerable speedup. For an example with a 512/spl times/512-pixel image and 1024 views, the speedup achieved with a particular implementation is over 40 fold, with reconstructions visually indistinguishable from the FBP.

Methods and systems for accessing multi-dimensional customer data

Abstract: Methods and systems for modeling customer data into a multi-dimensional structure for access to enable efficient customer targeting are described. The method includes the steps of compiling data from multiple sources to create a relational database, using tools to model data within the relational database, scoring the modeled data, integrating scores into a multi-dimensional structure and providing access to end users to the multi-dimensional structure.

Method for thermally spraying crack-free mullite coatings on ceramic-based substrates

Abstract: A process for depositing a mullite coating on a silicon-based material, such as those used to form articles exposed to high temperatures and including the hostile thermal environment of a gas turbine engine. The process is generally to thermally spray a mullite powder to form a mullite layer on a substrate, in which the thermal spraying process is performed so that the mullite powder absorbs a sufficient low level of energy from the thermal source to prevent evaporation of silica from the mullite powder. Processing includes deposition parameter adjustments or annealing to maintain or reestablish phase equilibrium in the mullite layer, so that through-thickness cracks in the mullite layer are avoided.

Experimental application of extremum seeking on an axial-flow compressor

Abstract: We show an application of the method of extremum seeking to the problem of maximizing the pressure rise in an axial-flow compressor. First we apply extremum seeking to the Moore-Greitzer model and design a feedback scheme actuated through a bleed valve which simultaneously stabilizes rotating stall and surge and steers the system towards the equilibrium with maximal pressure. Then we implement the scheme on a compressor rig in Murray's laboratory at the California Institute of Technology. We perform stabilization of rotating stall via air injection and implement extremum seeking through a slow bleed valve. The experiment demonstrates that extremum seeking ensures the maximization of the pressure rise starting on either side of the stall inception point. The experiment also resolves a concern that extremum seeking requires the use of periodic probing-the amplitude of probing needed to achieve convergence is far below the noise level of the compressor system (even outside rotating stall).

Online tracking of delivery status information over a computer network

Abstract: A method and system for tracking, over a computer network, orders placed with a supplier and shipped by any of a variety of different carriers, the tracking taking place entirely within the confines of the supplier's web site. By providing for electronic communication of delivery status information between a variety of different carriers and the supplier's server, the supplier is able to provide online tracking information to a customer regardless of the individual manner of delivery.

Fluid injector for and method of prolonged delivery and distribution of reagents into plasma

Abstract: A method and apparatus for injecting a fluid into a plasma stream with a uniform distribution and with reduced likelihood of clogging over prolonged use is provided. An injector includes a first channel portion for restricting a flow of the fluid and having a shape such that inner walls of the first channel portion are parallel to a first axis. The injector also includes a second channel portion in fluid communication with the first channel portion. The second channel portion includes a recessed portion such that inner walls of the second channel portion diverge from the first axis at a predetermined angle. The second channel portion reduces a buildup of a clogging layer on the inner walls of the second channel portion over a period of use. In addition, the injector can further include a tip portion that protrudes into the plasma. The injector can be integrated into or interchangeable within an injector system that can be designed for operation within a plasma deposition apparatus.

Methods and apparatus for model based diagnostics

Abstract: Systems and methods for performing module-based diagnostics are described. In an exemplary embodiment, sensor values from an actual engine plant are input to an engine component quality estimator which generates performance estimates of major rotating components. Estimated performance differences are generating by comparing the generated performance estimates to a nominal quality engine. The estimated performance differences, which are indicative of component quality, are continuously updated and input to a real-time model of the engine. The model receives operating conditional data and the quality estimates are used to adjust the nominal values in the model to more closely match the model values to the actual plant. Outputs from the engine model are virtual parameters, such as stall margins, specific fuel consumption, and fan/compressor/turbine efficiencies. The virtual parameters are combined with the sensor values from the actual engine plant in a fault detection and isolation classifier to identify abnormal conditions and/or specific fault classes, and output a diagnosis.

Artery and vein separation using susceptibility-dependent phase in contrast-enhanced MRA

Abstract: In magnetic resonance angiography, contrast agents are frequently used to help highlight arteries over background tissue. Unfortunately, enhancing veins hamper the visualization of arteries when data are collected over a long period of time after the arterial phase of the contrast agent. To overcome this problem, we have developed a novel imaging and postprocessing method that is capable of eliminating veins by utilizing the susceptibility difference between veins and surrounding tissue. This method was applied in the peripheral vasculature where the vessels are predominantly parallel to the main field and where the blood oxygen level-dependent effect is most pronounced. Results are presented for both long (15.8 msec) and short echo times (7.8 msec) and for sequential and centrally reordered acquisition schemes. The short echo scan approach appears to be the most promising, making it possible to obtain good suppression of the venous signal even when the timing is not perfect or when repeat scans are necessary.

Medical diagnostic system service connectivity method and apparatus

Abstract: A technique is provided for verifying network connectivity between a medical diagnostic system and a remote service facility. The remote service facility is contactable at will by the subscribing system to request service, information, technical assistance, and so forth, while the service facility may also contact the subscribing system for acquisition of data, transmission of service messages, protocols, and so forth. In the connectivity verification sequence, a subscribing system is selected by the service facility and a network connection is established. A message is transmitted to the system provoking software at the system to re-establish the network connection from the system side. Two-way connectivity is thereby verified. Mobile systems may be configured to contact the service facility at their own initiation, and exchange data for permitting the service facility to re-contact the mobile system. Failure modes may be identified at various locations in the connectivity network by identification of steps in the connectivity verification process where the process failed. Alerts or other action items may be generated as a result of detected connectivity problems.

Phosphors for light generation from light emitting semiconductors

Abstract: The phosphor A2DSi2O7:Eu2+, where A is at least one of Ba, Sr, Ca and D is Mg and Zn absorbs UV light, for example from an LED, and converts the UV light to green light. The phosphor can be combined with a red phosphor such as Y2O3:Eu3+,Bi3+ and one or more blue phosphors such as SECA ((Sr,Ba,Ca)5(PO4)3Cl:Eu2+) and BAM (BaMg2Al16O27:Eu2+) to produce white light. Also, a light emitting apparatus is disclosed which comprises at least one of a red, green and blue phosphor for absorbing and converting ultraviolet radiation from a light emitting semiconductor into visible light. A laser diode can be used to activate the phosphors to provide improved efficiency and brightness.

Thermally stable polymers, method of preparation, and articles made therefrom

Abstract: Thermally stable polymers comprising resorcinol arylate chain members are prepared using an interfacial method comprising the steps of: (a) combining at least one resorcinol moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water; and (b) adding to the mixture from (a) at least one dicarboxylic acid dichloride while maintaining the pH between 3 and 8.5 through the presence of an acid acceptor, wherein the total molar amount of acid chloride groups is stoichiometrically deficient relative to the total molar amount of phenolic groups.

Method and system for remotely managing communication of data used for predicting malfunctions in a plurality of machines

Abstract: A method and system for managing communication of electronic data between a diagnostic service center and a plurality of mobile assets (10) generally remote relative to each other is provided. The electronic data comprises at least respective mobile asset data indicative of respective performance of the plurality of mobile assets. The mobile asset data used for detecting the presence of potential malfunctions which, if left uncorrected, would likely result in respective mission failures of the assets. The method allows for storing in a database (104) a list of respective cases to be processed. The method further allows for assigning to each case a respective download priority. A determining action allows for determining each case to be populated next with new mobile asset data based upon the assigned download priority. Respective executing actions allow for executing a download of the new mobile asset between the diagnostic service center and a respective one of the mobile assets, and for executing predetermined analysis on the downloaded data for detecting the presence of respective potential malfunctions in the mobile assets. The download of data may be executed automatically whenever critical faults occur in the mobile assets.

Silicon based substrate with environmental/thermal barrier layer

Abstract: A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a barium-strontium alumino silicate.

System and method for automatically predicting the timing and costs of service events in a life cycle of a product

Abstract: A system and method for automatically predicting timing and costs of future service events in a life cycle of a product. A database contains a plurality of service information and performance information for the product. A statistical analyzer automatically analyzes the plurality of processed service information to determine a plurality of compartment failure information. A performance deterioration rate analyzer automatically analyzes the performance deterioration rate of the product from the plurality of service information and performance information. A simulator, automatically simulates a distribution of future service events in the life cycle of the product and predicts the costs of the service events according to the plurality of compartment failure information and the performance deterioration rate analysis.

A method for improving the cooling effectiveness of a gaseous coolant stream, and related articles of manufacture

Abstract: A method is described for improving the cooling effectiveness of a fluid which flows through a row of passage holes in a substrate (e.g., a turbine component), out to a high-temperature surface of the substrate. The method involves forming a slot over the holes, within the high temperature surface of the substrate. The slot can be formed within protective coatings applied over the substrate. Alternatively, it can be formed partially within the substrate, and partially within the protective coatings. Movement of a film coolant through the substrate and into the slot results in greater cooling effectiveness. Related articles are also described.

Crystalline gallium nitride and method for forming crystalline gallium nitride

Abstract: A gallium nitride growth process forms crystalline gallium nitride. The process comprises the steps of providing a source gallium nitride (15); providing mineralizer (17); providing solvent (17); providing a capsule (10); disposing the source gallium nitride, mineralizer and solvent in the capsule; sealing the capsule; disposing the capsule in a pressure cell (1); and subjecting the pressure cell to high pressure and high tempeature (HPHT) conditions for a length of time sufficient to dissolve the source gallium nitride and re-precipitate the source gallium nitride into at least one gallium nitride crystal. The invention also provides for gallium nitride crystals formed by the processes of the invention.