Showing papers by "General Electric published in 2005"

A review of shaped hole turbine film-cooling technology

Abstract: Film cooling represents one of the few game-changing technologies that has allowed the achievement of today's high firing temperature, high-efficiency gas turbine engines. Over the last 30 years, only one major advancement has been realized in this technology, that being the incorporation of exit shaping to the film holes to result in lower momentum coolant injection jets with greater surface coverage. This review examines the origins of shaped film cooling and summarizes the extant literature knowledge concerning the performance of such film holes. A catalog of the current literature data is presented, showing the basic shaping geometries, parameter ranges, and types of data obtained. Specific discussions are provided for the flow field and aerodynamic losses of shaped film hole coolant injection. The major fundamental effects due to coolant-to-gas blowing ratio, compound angle injection, cooling hole entry flow character, and mainstream turbulence intensity are each reviewed with respect to the resulting adiabatic film effectiveness and heat transfer coefficients for shaped holes. A specific example of shaped film effectiveness is provided for a production turbine inlet vane with comparison to other data. Several recent unconventional forms of film hole shaping are also presented as a look to future potential improvements

Quantitative equivalence between polymer nanocomposites and thin polymer films

Abstract: The thermomechanical responses of polymers, which provide limitations to their practical use, are favourably altered by the addition of trace amounts of a nanofiller. However, the resulting changes in polymer properties are poorly understood, primarily due to the non-uniform spatial distribution of nanoparticles. Here we show that the thermomechanical properties of ‘polymer nanocomposites’ are quantitatively equivalent to the well-documented case of planar polymer films. We quantify this equivalence by drawing a direct analogy between film thickness and an appropriate experimental interparticle spacing. We show that the changes in glass-transition temperature with decreasing interparticle spacing for two filler surface treatments are quantitatively equivalent to the corresponding thin-film data with a non-wetting and a wetting polymer–particle interface. Our results offer new insights into the role of confinement on the glass transition, and we conclude that the mere presence of regions of modified mobility in the vicinity of the particle surfaces, that is, a simple two-layer model, is insufficient to explain our results. Rather, we conjecture that the glass-transition process requires that the interphase regions surrounding different particles interact.

A comparison of three-level converters versus two-level converters for low-voltage drives, traction, and utility applications

Abstract: This paper evaluates three-level topologies as alternatives to two-level topologies in converters for low-voltage applications. Topologies, semiconductor losses, filter aspects, part count, initial cost, and life-cycle cost are compared for a grid interface, a conventional drive application, and a high-speed drive application.

Methods and apparatus for operating gas turbine engines

Abstract: A method for operating a gas turbine engine (10), including a first compressor (14), a second compressor (16), and a turbine (20), coupled together in serial flow arrangement. The method includes channeling compressed airflow (53) discharged from the first compressor through an intercooler (50) having a cooling medium flowing therethrough, operating the intercooler such that condensate is formed in the intercooler from the compressed airflow, and channeling the condensate to an inlet (26,30) of the first or second compressor to facilitate reducing an operating temperature of the gas turbine engine.

System and method for integrated learning and understanding of healthcare informatics

Abstract: An informatics system permits data entities from a wide range of data sources to be accessed and evaluated. The sources of the data entities may be simply data sources, such as for articles and other non-patient or population specific information, as well as controllable and prescribable sources, such diagnostic imaging, clinical and other sources forming part of the patient care path. The entities are organized, analyzed in accordance with a domain framework, which may be altered by a user to focus on factors and informational components of interest. Holistic and integrated understanding of such factors are there fore available, and refinement of healthcare processes can be made to provide improved care in a more time and cost effective manner.

System and method for operating a wind farm under high wind speed conditions

Abstract: A system and method of operating a wind farm (12), having multiple wind turbine generators (14, 16, 18), at high wind speeds is provided. Wind speeds at individual wind turbine generators (14, 16, 18) are monitored and a signal is transmitted from the wind turbine generators (14, 16, 18) to a wind farm control system (50) based on the monitored wind speeds. Rate of change of collective power output of the wind farm (12) is temporally monitored and is controlled by coordinating of operational states of the wind turbine generators (14, 16, 18) based upon the signals transmitted by the one or more wind turbine generators (14, 16, 18), operating conditions of the wind turbine generators (14, 16, 18) and the monitored rate of change of power output of the wind farm (12).

Optimal Estimation with Limited Measurements

Abstract: We consider a sequential estimation problem with two decision makers, or agents, who work as members of a team. One of the agents sits at an observation post, and makes sequential observations about the state of an underlying stochastic process for a fixed period of time. The observer agent upon observing the process makes a decision as to whether to disclose some information about the process to the other agent who acts as an estimator. The estimator agent sequentially estimates the state of the process. The agents have the common objective of minimizing a performance criterion with the constraint that the observer agent may only act a limited number of times.

Organic alternatives to quantum dots for intraoperative near-infrared fluorescent sentinel lymph node mapping.

Abstract: Intraoperative near-infrared (NIR) fluorescence imaging provides the surgeon with real-time image guidance during cancer and other surgeries. We have previously reported the use of NIR fluorescent quantum dots (QDs) for sentinel lymph node (SLN) mapping. However, because of concerns over potential toxicity, organic alternatives to QDs will be required for initial clinical studies. We describe a family of 800 nm organic heptamethine indocyanine-based contrast agents for SLN mapping spanning a spectrum from 775 Da small molecules to 7 MDa nanocolloids. We provide a detailed characterization of the optical and physical properties of these contrast agents and discuss the advantages and disadvantages of each. We present robust methods for the covalent conjugation, purification, and characterization of proteins with tetra-sulfonated heptamethine indocyanines, including mass spectroscopic site mapping of highly substituted molecules. One contrast agent, NIR fluorescent human serum albumin (HSA800), emerged as the molecule with the best overall performance with respect to entry to lymphatics, flow to the SLN, retention in the SLN, fluorescence yield and reproducibility. This preclinical study, performed on large animals approaching the size of humans, should serve as a foundation for future clinical studies. Mol Imaging (2005) 4, 172 – 181.

Physical interactions of static magnetic fields with living tissues.

Abstract: Clinical magnetic resonance imaging (MRI) was introduced in the early 1980s and has become a widely accepted and heavily utilized medical technology. This technique requires that the patients being studied be exposed to an intense magnetic field of a strength not previously encountered on a wide scale by humans. Nonetheless, the technique has proved to be very safe and the vast majority of the scans have been performed without any evidence of injury to the patient. In this article the history of proposed interactions of magnetic fields with human tissues is briefly reviewed and the predictions of electromagnetic theory on the nature and strength of these interactions are described. The physical basis of the relative weakness of these interactions is attributed to the very low magnetic susceptibility of human tissues and the lack of any substantial amount of ferromagnetic material normally occurring in these tissues. The presence of ferromagnetic foreign bodies within patients, or in the vicinity of the scanner, represents a very great hazard that must be scrupulously avoided. As technology and experience advance, ever stronger magnetic field strengths are being brought into service to improve the capabilities of this imaging technology and the benefits to patients. It is imperative that vigilance be maintained as these higher field strengths are introduced into clinical practice to assure that the high degree of patient safety that has been associated with MRI is maintained.

Method and apparatus for cooling combustor liner and transition piece of a gas turbine

Abstract: A method and apparatus for cooling a combustor liner and transitions piece of a gas turbine include a combustor liner with a plurality of circular ring turbulators arranged in an array axially along a length defining a length of the combustor liner and located on an outer surface thereof; a first flow sleeve surrounding the combustor liner with a first flow annulus therebetween including a plurality of axial channels (C) extending over a portion of an aft end portion of the liner parallel to each other, the cross-sectional area of each channel either constant or varying along the length of the channel, the first flow sleeve having a plurality of rows of cooling holes formed about a circumference of the first flow sleeve for directing cooling air from the compressor discharge into the first flow annulus; a transition piece connected to the combustor liner and adapted to carry hot combustion gases to a stage of the turbine; a second flow sleeve surrounding the transition piece a second plurality of rows of cooling apertures for directing cooling air into a second flow annulus between the second flow sleeve and the transition piece; wherein the first plurality of cooling holes and second plurality of cooling apertures are each configured with an effective area to distribute less than 50% of compressor discharge air to the first flow sleeve and mix with cooling air from the second flow annulus.

Methods and apparatus for reducing gas turbine engine emissions

Abstract: A low emission turbine includes a reverse flow can-type combustor that generally includes a primary and secondary fuel delivery system that can be independently controlled to produce low CO, UHC, and NOx emissions at design set point and at conditions other than design set point. The reverse flow can-type combustor generally includes an annularly arranged array of swirler and mixer assemblies within the combustor, wherein each swirler and mixer in the array includes a primary and secondary fuel delivery system that can be independently controlled. Also disclosed herein is a can-type combustor that includes fluid passageways that perpendicularly impinge the backside of a heat shield. Processes for operating the can-type combustors are also disclosed.

High efficiency inorganic nanorod-enhanced photovoltaic devices

Abstract: The present invention is directed to photovoltaic devices comprising nanostructured materials, wherein such photovoltaic devices are comprised exclusively of inorganic components. Depending on the embodiment, such nanostructured materials are either 1-dimensional nanostructures or branched nanostructures, wherein such nanostructures are used to enhance the efficiency of the photovoltaic device, particularly for solar cell applications. Additionally, the present invention is also directed at methods of making and using such devices.

High-voltage normally off GaN MOSFETs on sapphire substrates

Abstract: Gallium nitride self-aligned MOSFETs were fabricated using low-pressure chemical vapor-deposited silicon dioxide as the gate dielectric and polysilicon as the gate material. Silicon was implanted into an unintentionally doped GaN layer using the polysilicon gate to define the source and drain regions, with implant activation at 1100/spl deg/C for 5 min in nitrogen. The GaN MOSFETs have a low gate leakage current of less than 50 pA for circular devices with W/L=800/128 /spl mu/m. Devices are normally off with a threshold voltage of +2.7 V and a field-effect mobility of 45 cm/sup 2//Vs at room temperature. The minimum on-resistance measured is 1.9 m/spl Omega//spl middot/cm/sup 2/ with a gate voltage of 34 V (W/L=800/2 /spl mu/m). High-voltage lateral devices had a breakdown voltage of 700 V with gate-drain spacing of 9 /spl mu/m (80 V//spl mu/m), showing the feasibility of self-aligned GaN MOSFETs for high-voltage integrated circuits.

Wireless configurable controls and control panels and enclosures therefor

Abstract: An enclosure includes a control panel, a plurality of controls, indicators, or both mounted on said control panel or in the enclosure. At least some of the plurality of controls, indicators, or both are configured to wirelessly communicate with each other inside the enclosure, and at least some controls include wirelessly controlled relays configured to control devices outside the enclosure.

Thermal/Environmental barrier coating system for silicon-containing materials

Abstract: A coating system (14) for Si-containing materials, particularly Si-based composites used to produce articles (10) exposed to high temperatures. The coating system (14) is a compositionally-graded thermal/environmental barrier coating (T/EBC) system (14) that includes an intermediate layer (24) containing yttria-stabilized hafnia (YSHf) and mullite, alumina and/or an aluminosilicate, which is used in combination with an inner layer (22) between a Si-containing substrate (12) and the intermediate layer (24) and a thermal-insulating top coat (18) overlying the intermediate layer (24). The intermediate layer (24) provides environmental protection to the silicon-containing substrate (12), and has a coefficient of thermal expansion between that of the top coat (18) and that of the inner layer (22) so as to serve as a transition layer therebetween. The intermediate layer (24) is particular well suited for use in combination with an inner layer (22) of an alkaline earth metal aluminosilicate (such as BSAS) and a top coat (18) formed of YSZ or YSHf.

Surface passivated photovoltaic devices

Abstract: A photovoltaic device comprising a photovoltaic cell is provided. The photovoltaic cell includes an emitter layer comprising a crystalline semiconductor material and a lightly doped crystalline substrate disposed adjacent the emitter layer. The lightly doped crystalline substrate and the emitter layer are oppositely doped. Further, the photovoltaic device includes a back surface passivated structure coupled to the photovoltaic cell. The structure includes a highly doped back surface field layer disposed adjacent the lightly doped crystalline substrate. The highly doped back surface field layer includes an amorphous or a microcrystalline semiconductor material, wherein the highly doped back surface field layer and the lightly doped crystalline substrate are similarly doped, and wherein a doping level of the highly doped back surface field layer is higher than a doping level of the lightly doped crystalline substrate. Additionally, the structure may also include an intrinsic back surface passivated layer disposed adjacent the lightly doped crystalline substrate, where the intrinsic back surface passivated layer includes an amorphous or a microcrystalline semiconductor material.

Chest CT Performed with Z-Axis Modulation: Scanning Protocol and Radiation Dose

Abstract: Institutional review board approval of the study protocol and waiver of informed consent were obtained. This study was compliant with the Health Insurance Portability and Accountability Act. The purpose of this study was to retrospectively assess the scanning protocol and radiation dose associated with z-axis automatic tube current modulation in multi-detector row CT scanning of the chest. Fifty-three patients (mean age, 54 years; age range, 26-77 years; 25 men, 28 women) underwent 16-detector row chest CT with z-axis modulation and noise indexes of 10.0, 12.5, and 15.0 HU. Two radiologists independently compared images acquired with z-axis modulation and fixed tube current (180-300 mA) techniques for image noise, diagnostic acceptability, and depiction of peripheral bronchovascular markings. Tube current-time product was calculated for each study. There was good interobserver agreement between the two readers (kappa = 0.72). Compared with the fixed tube current technique, z-axis modulation provides acceptable image noise for chest CT, with an 18% and 26% reduction in tube current-time product at 10.0- and 12.5-HU noise indexes, respectively.

A carrier-based PWM scheme for neutral-point voltage balancing in three-level inverters

Abstract: A significant problem with neutral-point-clamped three-level inverters is the fluctuation in the neutral-point voltage. In this paper, a capacitor voltage balancing technique for carrier-based three-level pulsewidth modulation (PWM) is developed, with improved voltage control capability at high modulation index. The method incorporates a novel scheme that requires measurements of only the motor currents and capacitor voltages to implement voltage balancing control, and does not need to determine the direction of power flow between the inverter and the motor.

System and method for presentation of enterprise, clinical, and decision support information utilizing eye tracking navigation

Abstract: Certain embodiments of the present invention provide a method and system for using gaze detection to improve information display in a healthcare environment. Certain embodiments of a gaze detection and control system include an information system including information related to at least one image, a display device capable of displaying images and data, and a gaze tracking system for detection a location of a user's gaze with respect to the display device. The gaze tracking system triggers a retrieval of information from the information system based at least in part on the location of the user's gaze, and the retrieved information is displayed at the display device. In an embodiment, the retrieved information is overlaid over an image at the display device. In an embodiment, the gaze tracking system includes at least one camera and/or eyewear, for example.

Methods and apparatus for low emission gas turbine energy generation

Abstract: A low-emission method for producing power using a gas turbine includes premixing a plurality of fuel and air mixtures, injecting the fuel and air mixtures into a combustion chamber using a plurality of fuel nozzles, and adjusting a ratio of fuel and air injected by at least one of the nozzles to control a fuel/air concentration distribution within the combustion chamber

System and method for updating geo-fencing information on mobile devices

Abstract: A system and method of automatically replacing the geographic location of geo-fences stored in memory of a telematics system is described. The location of an asset is determined using an on-board telematics device with a location device. The location of the asset is compared with the location of predefined geo-fences stored in memory on the asset. When the asset is located within a geo-fence which triggers the replacement of geo-fences, the telematics system causes the asset to receive a new set of geo-fences, which replace the existing set of geo-fences in the telematics system memory. The operational cost of the system is reduced by minimizing communications charges when a reduced number of transmissions is needed to replace geo-fences stored in memory on the asset.

Locomotive wireless video recorder and recording system

Abstract: An imaging system for generating images taken from a rail vehicle, the system including a camera configured to generate video data associated with a rail vehicle, and a processor configured to control recording of video data according to at least one of a variable frame rate or a variable resolution based on operating conditions of the rail vehicle. A method and non-transitory computer readable medium with instructions are also included.

Fetal magnetic resonance imaging in the evaluation of fetuses referred for sonographically suspected abnormalities of the corpus callosum.

Abstract: Objective. Fetal magnetic resonance imaging (MRI) has been shown to be useful in assessing the developing central nervous system. However, its utility in specific brain disorders has not been well investigated. We hypothesized that fetal MRI can better assess the integrity of the brain in cases with sonographically suspected callosal abnormalities. Methods. We retrospectively reviewed fetal MRI and prenatal sonographic studies of 10 fetuses referred for MRI for sonographically suspected callosal abnormalities. Results. An abnormal corpus callosum was identified on fetal MRI in 80% of cases. The type of callosal abnormality (complete or partial agenesis) was similar on both prenatal sonography and fetal MRI in all cases. All sonographically identified additional brain abnormalities were detected on fetal MRI, with the exception of choroid plexus cysts. Furthermore, in 63% (5 of 8) of cases with a callosal abnormality on both sonography and fetal MRI, additional brain abnormalities were detected on fetal MRI that were not apparent on sonography. These sonographically occult findings were confirmed on postnatal MRI or autopsy in 3 of 5 patients. Conclusions. Fetal MRI is an important adjunct to sonography in assessing the corpus callosum and other aspects of brain development when agenesis of the corpus callosum is suspected. It can identify frequent additional findings that are not visible on sonography such as abnormal sulcation. In light of the association between additional brain abnormalities and worse neurodevelopmental outcome, the potential of fetal MRI as an important

Silicon Melt Infiltrated Ceramic Composites (HiPerComp

Abstract: Silicon melt infiltrated, SiC-based ceramic matrix composites (MI-CMCs) have been developed for use in gas turbine engines. These materials are particularly suited to use in gas turbines due to their low porosity, high thermal conductivity, low thermal expansion, high toughness and high matrix cracking stress. Several variations of the overall fabrication process for these materials are possible, but this paper will focus on “prepreg” and “slurry cast” MI-CMCs with particular reference to applications in power generation gas turbines. These composites have recently been commercialized under the name of HiPerComp™.

Thermally conductive composition and method for preparing the same

Abstract: Thermally conductive compositions containing spherical boron nitride filler particles having an average aspect ration of less than 20 in a polymer matrix