Showing papers by "General Electric published in 2002"

Delay-hopped transmitted-reference RF communications

Abstract: Previously, the authors have invented and experimented with a new radio communications scheme called delay-hopped transmitted-reference (DHTR) radio. This technique can function either as an impulse radio, or can employ a more traditional spread-spectrum carrier such as broadband noise. The DHTR method is well-suited to short-range transmissions in a high multipath environment, and, in contrast to time-modulated impulse radio, is easy to synchronize at the receiver. Finally, DHTR receivers and transmitters are not highly complex, and can be implemented in a cost-effective way.

Engineering and algorithm design for an image processing Api: a technical report on ITK--the Insight Toolkit.

Abstract: We present the detailed planning and execution of the Insight Toolkit (ITK), an application programmers interface (API) for the segmentation and registration of medical image data. This public resource has been developed through the NLM Visible Human Project, and is in beta test as an open-source software offering under cost-free licensing. The toolkit concentrates on 3D medical data segmentation and registration algorithms, multimodal and multiresolution capabilities, and portable platform independent support for Windows, Linux/Unix systems. This toolkit was built using current practices in software engineering. Specifically, we embraced the concept of generic programming during the development of these tools, working extensively with C++ templates and the freedom and flexibility they allow. Software development tools for distributed consortium-based code development have been created and are also publicly available. We discuss our assumptions, design decisions, and some lessons learned.

A grid simulator with control of single-phase power converters in D-Q rotating frame

Abstract: A control method in the direct-quadrature (DQ) rotating frame for a single-phase inverter or PFC rectifier is proposed to provide an infinite control gain (theoretically), thus zero steady state error at its fundamental frequency to achieve superior steady state and dynamic performance. This new control method transforms the physical "real circuit", in conjunction with an "imaginary orthogonal circuit", from the stationary frame to the DQ rotating frame so that the steady state voltage/current in the DQ frame become DC variables. The new control concept is validated through a single-phase grid simulator used for utility compatibility tests, as described in IEEE P1547 draft standard, IEEE Std 929, UL 1741 and NYSIR, for single-phase distributed generators (DG), such as residential fuel cell generators or photovoltaic power conditioning systems. Experimental results in steady state with programmable simulated utility line impedance are given along with the dynamic transient response for NYSIR type test. The control concept is also applicable to zero-sequence control for three-phase four-wire systems.

Performance analysis of a three-phase induction motor under mixed eccentricity condition

Abstract: A substantial portion of induction motor faults is eccentricity related. In practice, static as well as dynamic eccentricities happen to exist together. With this point in mind, an analytical approach to evaluate performance of a three-phase induction motor under mixed eccentric condition has been presented in this paper. Clear and step-by-step theoretical analysis, explaining completely the presence of certain harmonics in the line current spectrum in presence of eccentricity, is discussed. More importantly, it is shown for the first time that a link exists between the lowi and the high-frequency elements of these harmonics. It is also shown that these high-frequency components are not very strong in all types of machines. These results will be useful in generating rules and laws to formulate on-line tools for machine condition monitoring. Finite element results to substantiate the inductance values used in the simulation are also included. The analysis is validated by the line current spectrum of the eccentric machine obtained through simulation using modified winding function approach (MWFA) and experimentation.

Electronic purchasing method and apparatus for performing the same

Abstract: A computer-assisted method includes hardware, software and telecommunications components that cooperatively achieve the technical effect of an improved electronic purchasing transaction system. In various embodiments of the invention, at least one master account is established for a client. A pool of limited use account identifiers or secondary account identifiers, that are separate and distinct from the master account, is associated with the master account by a purchasing system or account management system. Each of the limited use account identifiers may be used by the client to purchase items from merchants.

Method and apparatus for controlling electronically commutated motor operating characteristics

Abstract: A permanent magnet DC brushless motor control assembly permits a user to select the permanent magnet DC brushless motor operating characteristics by selecting appropriate control circuits to interface with the motor. The assembly includes a permanent magnet DC brushless motor, a commutator electrically coupled to the motor, and at least one control module electrically coupled to the commutator, to control operating characteristics of the permanent magnet DC brushless motor.

Toward perfect antireflection coatings: numerical investigation.

Abstract: A perfect antireflection (AR) coating would remove completely the reflection from an interface between two media for all wavelengths, polarizations, and angles of incidence. The degree to which this can be achieved is investigated numerically. It is shown that wideband solutions can be found provided that layers can be deposited with refractive indices that are close to that of the low-index medium. Thus realistic solutions exist for interfaces between two solid media. Narrow-band high-angle AR solutions are also possible for polarized light and for unpolarized light in the vicinity of certain reststrahlen bands.

Adaptive model-based control systems and methods for controlling a gas turbine

Abstract: Adaptive model-based control systems and methods are described so that performance and/or operability of a gas turbine in an aircraft engine, power plant, marine propulsion, or industrial application can be optimized under normal, deteriorated, faulted, failed and/or damaged operation. First, a model of each relevant system or component is created, and the model is adapted to the engine. Then, if/when deterioration, a fault, a failure or some kind of damage to an engine component or system is detected, that information is input to the model-based control as changes to the model, constraints, objective function, or other control parameters. With all the information about the engine condition, and state and directives on the control goals in terms of an objective function and constraints, the control then solves an optimization so the optimal control action can be determined and taken. This model and control may be updated in real-time to account for engine-to-engine variation, deterioration, damage, faults and/or failures using optimal corrective control action command(s).

Diffusion and tunneling currents in GaN/InGaN multiple quantum well light-emitting diodes

Abstract: We have studied the electrical characteristics and optical properties of GaN/InGaN multiple quantum well (MQW) light-emitting diodes (LEDs) grown by metalorganic chemical vapor deposition. It appears that there is an essential link between material quality and the mechanism of current transport through the wide-bandgap p-n junction. Tunneling behavior dominates throughout all injection regimes in a device with a high density of defects in the space-charge region, which act as deep-level carrier traps. However, in a high-quality LED diode, temperature-dependent diffusion-recombination current has been identified with an ideality factor of 1.6 at moderate biases. Light output has been found to follow a power law, i.e., L /spl prop/ I/sup m/ in both devices. In the high-quality LED, nonradiative recombination centers are saturated at current densities as low as 1.4 /spl times/ 10/sup -2/ A/cm/sup 2/. This low saturation level indicates that the defects in GaN, especially the high density of edge dislocations, are generally optically inactive.

Coupling and decoupling theory and its application to the MRI phased array

Abstract: In classical MRI phased-array design, optimal coil overlapping is used to minimize coupling between nearest-neighbor coils, and low input impedance preamplifiers are used to isolate the relatively weak coupling between non-nearest neighbors. However, to make the complex sensitivities of phased-array coils sufficiently distinct in parallel spatially-encoded MRI, it is desirable to have no overlapping between coils. Also, if phased arrays are used as transmit coils in MRI, one can no longer rely on the low input impedance of the preamplifiers for decoupling. Here a coupling and decoupling theory is introduced to provide a better understanding of the relations between coupled and uncoupled signals in the MRI phased array, and to offer a new method for decoupling phased-array coils without overlapping the nearest coil pairs. The new decoupling method is based on the assumption that any n-element phased array can be decoupled by a 2n-port interface system between phased array and preamplifiers. The detailed analysis and the experimental results show that a four-port interface can be used to decouple a two-element phased array. Furthermore, the four-port interfaces can serve as building blocks to construct a 2n-port decoupling interface. This new method allows one to place the coil elements anywhere that could optimize parallel spatial encoding without concern for coupling between the coils. The method can also be used for phased-array transmit coils.

Dual-rotor, radial-flux, toroidally-wound, permanent-magnet machines

Abstract: A novel machine family-dual-rotor, radial-flux, toroidally wound, permanent-magnet (RFTPM) machines-is proposed in order to substantially improve machine torque density and efficiency. After the principles of operation, configurations, and features are discussed, the machine design and optimization guidelines are given. A prototype has been designed, built, and tested. The measured torque density of the prototype, which well matches the design value, is almost three times of that of the induction machine with the same power of 3 hp and speed. Meanwhile the efficiency is still kept high and the material cost is kept low by using ferrite magnets. Three novel approaches are proposed to reduce the cogging torque in the RFTPM machines, whose validity is verified by finite-element analysis results and experimental measurements.

Mechanical behavior of Ti-6Al-4V at high and moderate temperatures-Part II: constitutive modeling

Abstract: A physically-based model for the deformation of Ti–6%–Al-4%V is proposed. The various deformation mechanisms active in this material over the whole range of temperatures of industrial interest are discussed, and a strategy by which the relevant strengthening effects are captured in the model is proposed. The flow stress contains a thermal and an athermal component. The thermally activated processes are modeled based on the Kocks–Mecking formalism, while the athermal processes are simulated using an internal state variable. The deformation of the α-and β-phases is captured separately. The model is calibrated based on experimental results obtained from tests performed in the temperature range (77–1400 K) and at strain rates between 10 −3 and 10 s −1 . The model predictions are extrapolated to strain rates as high as 2000 s −1 . The experimental findings are presented in the companion paper.

An interim dynamic induction motor model for stability studies in the WSCC

Abstract: An "interim" composite load model containing a static part and a dynamic part has been implemented in the Western Systems Coordinating Council (WSCC) The static part of the load model is about 80% of the total load and comprises of existing static load data from the WSCC members The dynamic part is a default induction motor model for approximately 20% of the total load This composite model is used for all loads in the full-scale WSCC grid models that are the basis for system interconnection studies The model is designed primarily to capture the effects of dynamic induction motor loads for highly stressed north to south flow conditions during summer peaks in the WSCC

Phosphor blends and backlight sources for liquid crystal displays

Abstract: A phosphor composition that comprises at least one phosphor emitting in each of the blue, green, and red regions of the visible spectrum is disposed adjacent to a backlight source of a color liquid crystal display. The phosphor composition emits strongly in the wavelength ranges of color filters used in such display. The backlight source includes either a semiconductor light-emitting diode or an organic light-emitting device.

Interactive method and system for faciliting the development of computer software applications

Abstract: A comprehensive method and system is provided for developing and implementing new computer software applications through a series of distinct stages. Following the completion of each stage, a tollgate meeting is held between the various parties involved and a decision as made on whether the project should be advanced to the next stage. Guidelines, templates and checklist items are provided for each stage in a user-friendly manner over an interactive computer interface, such as a web page. By providing on-line guidance to project developers, the system and method of the present invention substantially decreases the likelihood of errors being made which introduce costs in both time, resources, and risk. Further, the present system, through its comprehensive, global nature, substantially increases the ability for distributed locations to stay in tune with what each other are doing. Because all locations must develop applications in accordance with the above-described system, added consistency results.

Mechanical behavior of Ti–6Al–4V at high and moderate temperatures—Part I: Experimental results

Abstract: This study investigates the plastic deformation of titanium alloy Ti–6%Al–4%V under low and moderate strain rates and various temperature conditions. Mechanical testing is performed in the temperature range 650–1340 K (710–1950 °F) and under constant strain rate loading ranging from 10 −3 to 10 s −1 . The test results are correlated with the evolution of the microstructure and compared to published data. The flow stress of this alloy is strongly dependent on both temperature and deformation rate, with the temperature effect becoming negligible in the upper part of the temperature range investigated. At temperatures above 800 K (980 °F) the flow stress decreases sharply with temperature. The effect of deformation rate on this transition is investigated and the possible mechanisms responsible for the behavior are discussed. Based on these experimental results, a physically-based constitutive law is developed in the sequel of this paper.

Film Cooling Effectiveness Due to Discrete Holes Within a Transverse Surface Slot

Abstract: The goal of many turbine airfoil film cooling schemes is the achievement of a tangentially injected 2D layer of protective film over the surface. In common nomenclature, this is referred to as 2D slot film cooling, which can achieve adiabatic effectiveness levels approaching unity at the injection location. Since continuous and uninterrupted slots are not structurally feasible in the high pressure turbine components, other approximate film cooling geometries have been sought. The present study examines two film cooling geometries which are formed by the combination of internal discrete film holes feeding continuous 2D surface slots. Experiments have been performed within a flat plate wind tunnel test section, which includes an accelerating freestream condition to model the surface of a turbine airfoil. As suggested by the experiments of Wang et al. [1], a normal 2D surface slot is located transverse to the mainstream flow direction. The slot is fed by a row of discrete coolant supply holes oriented in the spanwise direction with inclination angle of 30-degrees, pitch-to-diameter ratio of 3.57, and length-to-diameter ratio of 5.7. The slot depth-to-hole diameter ratio is S/D of 3. Two such slots were tested, one with axial width-to-hole diameter ratio of 1.13, and the other with ratio of 1.5. Tests were conducted for supply hole blowing ratios of 0.75 to 4, density ratios of 1.8, and a freestream approach turbulence intensity of 4.5%. The holes-within-slot film effectiveness data are compared with both axial and radial film data, ie. S/D equal to zero, obtained in the same test section. The holes-in-slot geometries demonstrate two important characteristics, (1) a relative insensitivity of the adiabatic film effectiveness to blowing rate, and (2) no observed film blow-off at high blowing rates. In addition, a novel film cooling arrangement is demonstrated in which the surface slot is very shallow, forming a narrow trench with S/D of only 0.43. It is shown that this novel surface geometry yields the best film effectiveness of all cases tested.Copyright © 2002 by ASME

Computer aided diagnosis of an image set

Abstract: A method, system, and storage medium for computer aided processing of an image set includes employing a data source, the data source including an image set acquired from X-ray projection imaging, x-ray computed tomography, or x-ray tomosynthesis, defining a region of interest within one or more images from the image set, extracting feature measures from the region of interest, and reporting at least one of the feature measures on the region of interest. The method may be employed for identifying bone fractures, disease, obstruction, or any other medical condition.

Apparatus and method for large area chemical vapor deposition using multiple expanding thermal plasma generators

Abstract: Chemical vapor deposition is performed using a plurality of expanding thermal plasma generating means to produce a coating on a substrate, such as a thermoplastic and especially a polycarbonate substrate. The substrate is preferably moved past the generating means. Included are methods which coat both sides of the substrate or which employ multiple sets of generating means, either in a single deposition chamber or in a plurality of chambers for deposition of successive coatings. The substrate surfaces spaced from the axes of the generating means are preferably heated to promote coating uniformity.

Light-emitting device with organic layer doped with photoluminescent material

Abstract: A light-emitting device includes an anode, a cathode, and at least one organic electroluminescent (“EL”) material positioned between the anode and the cathode. Nanoparticles of at least one photoluminescent material are dispersed in the organic EL material. The organic EL material emits a first electromagnetic (“EM”) radiation having a first spectrum in response to an applied electrical field. The PL material absorbs a portion of the first EM radiation emitted by the organic EL material and emits a second EM radiation having a second spectrum. A plurality of the light-emitting devices are arranged on a transparent substrate to provide a panel display or a lighting source.

Method and system for diagnosing machine malfunctions

Abstract: A system ( 830 ) and method ( 800 ) for diagnosing a malfunctioning machine. A fault event is selected ( 806 ) together with sequential operating parameter data ( 808 ) from a selectively focused time interval about the fault event for evaluation of a machine ( 810 ). The selectively focused time interval may include data occurring just before, just after, or spanning the fault event. Characterizing information such as slope, rate of change, and absolute sign of the data may be derived ( 809 ) from the operating parameter data over the selectively focused time interval and used in the diagnosis. The fault event and operating parameter data may be compared to existing cases in a case database ( 834 ). A set of rules ( 817 ) or candidate anomalies ( 841 ) may be executed over the operating parameter data to further improve the accuracy of the diagnosis.

Jet aircraft fan case containment design

Abstract: A jet aircraft fan case containment design that uses polyurethane to absorb fan blade fragments and uses polyurethane to prevent fan blade fragments from penetrating the fan case. The polyurethane is used in place of or to supplement KEVLAR® and/or fiberglass wraps used to contain fan blade fragments. The polyurethane is also used in place of aluminum alloy and stiffening ribs in the fan case.

Method, system and computer product for cardiac interventional procedure planning

Abstract: A method of creating 3D models to be used for cardiac interventional procedure planning. Acquisition data is obtained from a medical imaging system and cardiac image data is created in response to the acquisition data. A 3D model is created in response to the cardiac image data and three anatomical landmarks are identified on the 3D model. The 3D model is sent to an interventional system where the 3D model is in a format that can be imported and registered with the interventional system.

Layered phosphor coatings for led devices

Abstract: A light emitting device comprised of a light emitting diode on a mounting surface, the light emitting diode includes a substrate layer and at least one active region. A resilient substantially transparent and substantially phosphor free polymer layer extends from the mounting surface to above at least one quarter of a height of the substrate layer but below a top surface of the light emitting diode. A second phosphor containing layer extends from the phosphor free polymer layer to above the top surface of the light emitting diode.

Methods and apparatus for model predictive control of aircraft gas turbine engines

Abstract: A method of designing the operations and controls of a aircraft gas turbine engine includes generating an operations model for the gas turbine include at least one objective function, defining operations and control constraints for the operations model of the gas turbine, and providing an online dynamic optimizer/controller that dynamically optimizes and controls operation of the gas turbine using model predictive control based on the operations model and the operations and control constraints using an Extended Kalman Filter for estimation.

Counter rotating aircraft gas turbine engine with high overall pressure ratio compressor

Abstract: An aircraft gas turbine engine includes high and low pressure turbines having respective counter rotatable low pressure inner and outer rotors with low pressure inner and outer shafts in part rotatably disposed co-axially within a high pressure rotor and drivingly connected to first and second fan blade rows and first and second boosters respectively. A bypass duct radially bounded by a fan casing and an annular radially inner bypass duct wall surrounds the boosters axially located between the first and second fan blade rows. The engine has a high pressure compressor operable to produce an overall pressure ratio in a range of about 40-65 and a fan inlet hub to tip radius ratio in a range between 0.20 and 0.35, a bypass ratio in a range of 5-15, an operational fan pressure ratio in a range of 1.4-2.5, and a sum of operational fan tip speeds in a range of 1000 to 2500 feet per second.

Oxygen fired circulating fluidized bed steam generator

Abstract: A circulating fluidized bed steam generator 10 and a method for operating the circulating fluidized bed steam generator are provided which offer the flexibility to use carbon dioxide (CO2) both as a desirable end product and as support to the combustion process. The method includes the step of introducing a substantially pure oxygen feed stream into the circulating fluidized bed steam generator 10 and the step of combusting a fuel in the presence of the substantially pure oxygen feed stream to produce a flue gas having carbon dioxide and water vapor as its two largest constituent elements by volume. The method also includes the step of passing the flue gas through an oxygen feed stream pre-heater 144 at which heat from the flue gas is transferred to the oxygen feed stream. Furthermore the method includes the step of separating the flue gas into an end product portion and a recycling portion. The method additionally includes cooling and compressing the end product portion of the flue gas so as to yield carbon dioxide in a liquid phase and directing the recycling portion of the flue gas to the circulating fluidized bed steam generator 10 to contribute to the combustion process therein.