1,184 research outputs found

    Perception and use of graywater in Berkeley, California

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    National instruments labVIEW and video imaging technique for health status monitoring

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    A Direct Adaptive Control Approach in the Presence of Model Mismatch

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    This paper considers the problem of direct model reference adaptive control when the plant-model matching conditions are violated due to abnormal changes in the plant or incorrect knowledge of the plant's mathematical structure. The approach consists of direct adaptation of state feedback gains for state tracking, and simultaneous estimation of the plant-model mismatch. Because of the mismatch, the plant can no longer track the state of the original reference model, but may be able to track a new reference model that still provides satisfactory performance. The reference model is updated if the estimated plant-model mismatch exceeds a bound that is determined via robust stability and/or performance criteria. The resulting controller is a hybrid direct-indirect adaptive controller that offers asymptotic state tracking in the presence of plant-model mismatch as well as parameter deviations

    Vertical Navigation Control Laws and Logic for the Next Generation Air Transportation System

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    A vertical navigation (VNAV) outer-loop control system was developed to capture and track the vertical path segments of energy-efficient trajectories that are being developed for high-density operations in the evolving Next Generation Air Transportation System (NextGen). The VNAV control system has a speed-on-elevator control mode to pitch the aircraft for tracking a calibrated airspeed (CAS) or Mach number profile and a path control mode for tracking the VNAV altitude profile. Mode control logic was developed for engagement of either the speed or path control modes. The control system will level the aircraft to prevent it from flying through a constraint altitude. A stability analysis was performed that showed that the gain and phase margins of the VNAV control system significantly exceeded the design gain and phase margins. The system performance was assessed using a six-deg-of-freedom non-linear transport aircraft simulation and the performance is illustrated with time-history plots of recorded simulation data

    Technical Efficiency of Resource-Conserving Technologies in Rice -Wheat Systems: The Case of Bihar and Eastern Uttar Pradesh in India

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    This study has evaluated the technical efficiency of farmers engaged in rice-wheat cropping systems in North-eastern India, who are using Resource-Conserving Technologies (RCTs) such as Zero Tillage (ZT) and Direct Seeded Rice (DSR). These technology promotions are being carried out under the intervention of the Cereal Systems Initiative for South Asia (CSISA) project, primarily funded by the Bill and Melinda Gates Foundation. The resource-conserving technologies are being promoted as part of conservation agriculture supported by the project. The data used in this study have been derived from the socioeconomic surveys conducted in Eastern Uttar-Pradesh and Bihar in North-eastern India during the kharif season of 2009 and rabi season of 2010. A stochastic frontier analysis was carried out to investigate and compare the determinants of technical efficiency among the farmers receiving intervention and those who are not. The study has revealed that farmers receiving CSISA intervention have realized higher levels of technical efficiency. Additionally, farmers who are receiving subsidies and farmers who are planting more diversified crops have higher levels of technical efficiency.Conservation agriculture, Direct seeded rice, India, Resource-conserving technology, Technical efficiency, Stochastic frontier, Zero tillage, Agricultural and Food Policy, O30, Q18, O22,

    Resident phenotypically modulated vascular smooth muscle cells in healthy human arteries.

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    Vascular interstitial cells (VICs) are non-contractile cells with filopodia previously described in healthy blood vessels of rodents and their function remains unknown. The objective of this study was to identify VICs in human arteries and to ascertain their role. VICs were identified in the wall of human gastro-omental arteries using transmission electron microscopy. Isolated VICs showed ability to form new and elongate existing filopodia and actively change body shape. Most importantly sprouting VICs were also observed in cell dispersal. RT-PCR performed on separately collected contractile vascular smooth muscle cells (VSMCs) and VICs showed that both cell types expressed the gene for smooth muscle myosin heavy chain (SM-MHC). Immunofluorescent labelling showed that both VSMCs and VICs had similar fluorescence for SM-MHC and αSM-actin, VICs, however, had significantly lower fluorescence for smoothelin, myosin light chain kinase, h-calponin and SM22α. It was also found that VICs do not have cytoskeleton as rigid as in contractile VSMCs. VICs express number of VSMC-specific proteins and display features of phenotypically modulated VSMCs with increased migratory abilities. VICs, therefore represent resident phenotypically modulated VSMCs that are present in human arteries under normal physiological conditions

    Hybrid energy and angle dispersive X-ray diffraction computed tomography

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    Pixelated energy resolving detectors enable acquisition of X-ray diffraction (XRD) signals using a hybrid energy- and angle- dispersive technique, potentially paving the way for the development of novel benchtop XRD imaging or computed tomography (XRDCT) systems, utilising readily available polychromatic X-ray sources. In this work, a commercially available pixelated cadmium telluride (CdTe) detector, HEXITEC (High Energy X-ray Imaging Technology), was used to demonstrate such an XRDCT system. Specifically, a novel fly-scan technique was developed and compared to the established step-scan technique, reducing the total scan time by 42% while improving the spatial resolution, material contrast and therefore the material classification

    Ultrashort time-to-echo MRI of the cartilagenous endplate and relationship to degenerative disc disease and schmorl's nodes

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    Session - The Short of ItINTRODUCTION: The vertebral endplate is composed of an inner bony and outer cartilaginous endplates (CEP). The CEP supplies the intervertebral disc (IVD) with nutrients and metabolites, and is instrumental for metabolism, exchange of waste products and biomechanics of the disc 1. Lumbar disc degeneration on MRI is a risk factor for the development of low back pain 2. It has been previously hypothesized that changes in disc mechanics may be initiated by damage to the endplate 3, 4. Similarly, CEP defects may be involved in the formation of Schmorl’s nodes (SNs) (i.e. invagination of IVD material into the adjacent endplates) 5, which associated with severity of lumbar disc degeneration 6. The ultrashort time-to-echo (UTE) MRI is an imaging technique that enables improved visualization of tissues with short T2 relaxation that appear dark in signal on conventional T2-weighted (T2W) imaging. By employing this technique in the lumbar spine, we believe that the CEP, which appears hypointense in T2W MRI, may be observed as continuous high-signal and may thus be differentiated from the bony endplate. Although cadaveric studies have addressed the feasibility of UTE in assessing the CEP 7, studies addressing such technology in live human subjects …published_or_final_versionThe 19th Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine (ISMRM 2011), Montreal, QC., 7-13 May 2011. In Proceedings of the 19th ISMRM, 2011, v. 19, p. 57
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