Science.gov

Sample records for affecting device performance

  1. Factors affecting intrauterine contraceptive device performance. I. Endometrial cavity length.

    PubMed

    Hasson, H M; Berger, G S; Edelman, D A

    1976-12-15

    The relationship of endometrial cavity length to intrauterine contraceptive device (IUD) performance was evaluated in 319 patients wearing three types of devices. The rate of events, defined as pregnancy, expulsion, or medical removal, increased significantly when the length of the IUD was equal to, exceeded, or was shorter by two or more centimeters than the length of the endometrial cavity. Total uterine length was found to be a less accurate prognostic indicator of IUD performance than endometrial cavity length alone.

  2. Device Performance

    SciTech Connect

    Not Available

    2006-06-01

    In the Device Performance group, within the National Center for Photovoltaic's Measurements and Characterization Division, we measure the performance of PV cells and modules with respect to standard reporting conditions--defined as a reference temperature (25 C), total irradiance (1000 Wm-2), and spectral irradiance distribution (IEC standard 60904-3). Typically, these are ''global'' reference conditions, but we can measure with respect to any reference set. To determine device performance, we conduct two general categories of measurements: spectral responsivity (SR) and current versus voltage (I-V). We usually perform these measurements using standard procedures, but we develop new procedures when required by new technologies. We also serve as an independent facility for verifying device performance for the entire PV community. We help the PV community solve its special measurement problems, giving advice on solar simulation, instrumentation for I-V measurements, reference cells, measurement procedures, and anomalous results. And we collaborate with researchers to analyze devices and materials.

  3. Investigation of factors affecting terrestrial passive sampling device performance and uptake rates in laboratory chambers

    SciTech Connect

    Johnson, K.A.; Weisskopf, C.P.

    1995-12-31

    A rapid sampling method using passive sampling devices (PSDS) for soil contaminant characterization shows extreme promise. The use of PSDs increases ease and speed of analysis, decreases solvent usage and cost, and minimizes the transport of contaminated soils. Time and cost savings allow a high sampling frequency, providing a more thorough site characterization than traditional methods. The authors have conducted both laboratory and field studies with terrestrial PSDS. Laboratory studies demonstrated the concentration and moisture dependence of sampler uptake and provided an estimate of the optimal field sampling time for soils contaminated with polychlorinated biphenyls (PCBs). These PSDs were also used to accurately estimate PCB concentrations at hazardous waste site where concentrations ranged from 0.01 to 200 ug PCB/g soil. However, PSDs in the field had sampling rates approximately three times greater than in the laboratory. As a result several factors affecting PSD sampling rates and/or performance in laboratory chambers were evaluated. The parameters investigated were soil bulk density or compactness, chamber size and air flow. The chemicals used in these studies included two PCB congeners (52 and 153), three organochlorine pesticides (DDT, dieldrin and methoxychlor), three organophosphate pesticides (chlorpyrifos, diazinon and terbufos) and three herbicides (alachlor, atrazine and metolachlor).

  4. The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks

    PubMed Central

    Müller, Corsin A.; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

    2014-01-01

    Visible and invisible displacement tasks have been used widely for comparative studies of animals’ understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and thus reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so due to their inability to form a mental representation of the target object, or simply due to the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object’s location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species’ performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past. PMID:24611641

  5. Domain compositions in the active layer of low band gap polymer/fullerene solar cells strongly affect device performance

    NASA Astrophysics Data System (ADS)

    Vajjala Kesava, Sameer; Fei, Zhuping; Heeney, Martin; Wang, Cheng; Hexemer, Alexander; Gomez, Enrique; Enrique Gomez-Martin Heeney Collaboration; Enrique Gomez-Alexander Hexemer Collaboration

    2013-03-01

    We have characterized the morphology of mixtures of a germole-containing polymer, poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]germole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (PGeBTBT), and PCBM using Resonance Soft X-ray Scattering (RSOXS) and Energy-Filtered Transmission Electron Microscopy (EFTEM). PGeBTBT belongs to cyclopentadithiophene-based polymer family with a band gap of 1.5 eV. Analyses of RSOXS data and EFTEM images have shown that the volume fraction of polymer in the fullerene matrix enveloping PGeBTBT fibers (~10 nm diameter) decreases with increasing overall composition of PCBM. Furthermore, PGeBTBT/PCBM devices demonstrate a correlation between the short circuit current and the purity of the PCBM-rich phase. We hypothesize that the relationship between PCBM domain composition and device performance is related to charge recombination, where increasing the polymer content suppresses charge transport thereby increasing the transit time. Acknowledgements: NSF; ALS, LBL; Penn Regional Nanotechnology Facility, University of Pennsylvania

  6. Defects and device performance

    NASA Technical Reports Server (NTRS)

    Storti, G.; Armstrong, R.; Johnson, S.; Lin, H. C.; Regnault, W.; Yoo, K. C.

    1985-01-01

    The necessity for a low-cost crystalline silicon sheet material for photovoltaics has generated a number of alternative crystal growth techniques that would replace Czochralski (Cz) and float-zone (FZ) technologies. Efficiencies of devices fabricated from low resistivity FZ silicon are approaching 20%, and it is highly likely that this value will be superseded in the near future. However, FZ silicon is expensive, and is unlikely ever to be used for photovoltaics. Cz silicon has many of the desirable qualities of FZ except that minority-carrier lifetimes at lower resistivities are significantly less than those of FZ silicon. Even with Cz silicon, it is unlikely that cost goals can be met because of the poor-material yield that results from sawing and other aspects of the crystal rowth. Although other silicon sheet technologies have been investigated, almost all have characteristics that limit efficiency to approx. 16%. In summary, 20% efficient solar cells can likely be fabricated from both FZ and Cz silicon, but costs are likely to be ultimately unacceptable. Alternate silicon technologies are not likely to achieve this goal, but cost per watt figures may be eventually better than either of the single crystal technologies and may rival any thin-film technology.

  7. Quantum Tunneling Affects Engine Performance.

    PubMed

    Som, Sibendu; Liu, Wei; Zhou, Dingyu D Y; Magnotti, Gina M; Sivaramakrishnan, Raghu; Longman, Douglas E; Skodje, Rex T; Davis, Michael J

    2013-06-20

    We study the role of individual reaction rates on engine performance, with an emphasis on the contribution of quantum tunneling. It is demonstrated that the effect of quantum tunneling corrections for the reaction HO2 + HO2 = H2O2 + O2 can have a noticeable impact on the performance of a high-fidelity model of a compression-ignition (e.g., diesel) engine, and that an accurate prediction of ignition delay time for the engine model requires an accurate estimation of the tunneling correction for this reaction. The three-dimensional model includes detailed descriptions of the chemistry of a surrogate for a biodiesel fuel, as well as all the features of the engine, such as the liquid fuel spray and turbulence. This study is part of a larger investigation of how the features of the dynamics and potential energy surfaces of key reactions, as well as their reaction rate uncertainties, affect engine performance, and results in these directions are also presented here.

  8. High performance thermoelectric nanocomposite device

    DOEpatents

    Yang, Jihui; Snyder, Dexter D.

    2011-10-25

    A thermoelectric device includes a nanocomposite material with nanowires of at least one thermoelectric material having a predetermined figure of merit, the nanowires being formed in a porous substrate having a low thermal conductivity and having an average pore diameter ranging from about 4 nm to about 300 nm.

  9. Performance of Installed Cooking Exhaust Devices

    SciTech Connect

    Singer, Brett C.; Delp, William W.; Apte, Michael G.; Price, Philip N.

    2011-11-01

    The performance metrics of airflow, sound, and combustion product capture efficiency (CE) were measured for a convenience sample of fifteen cooking exhaust devices, as installed in residences. Results were analyzed to quantify the impact of various device- and installation-dependent parameters on CE. Measured maximum airflows were 70% or lower than values noted on product literature for 10 of the devices. Above-the-cooktop devices with flat bottom surfaces (no capture hood) – including exhaust fan/microwave combination appliances – were found to have much lower CE at similar flow rates, compared to devices with capture hoods. For almost all exhaust devices and especially for rear-mounted downdraft exhaust and microwaves, CE was substantially higher for back compared with front burner use. Flow rate, and the extent to which the exhaust device extends over the burners that are in use, also had a large effect on CE. A flow rate of 95 liters per second (200 cubic feet per minute) was necessary, but not sufficient, to attain capture efficiency in excess of 75% for the front burners. A-weighted sound levels in kitchens exceeded 57 dB when operating at the highest fan setting for all 14 devices evaluated for sound performance.

  10. Performance Assessment of Passive Hearing Protection Devices

    DTIC Science & Technology

    2014-10-24

    AFRL-RH-WP-TR-2014-0148 Performance Assessment of Passive Hearing Protection Devices Hilary L. Gallagher Richard L. McKinley...Assessment of Passive Hearing Protection Devices 5a. CONTRACT NUMBER FA8650-14-D-6501 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62202F 6. AUTHOR(S...is essential. Passive hearing protectors, capable of attenuating both continuous and impulsive noise, have been designed to reduce the risk of

  11. Wearable Performance Devices in Sports Medicine

    PubMed Central

    Li, Ryan T.; Kling, Scott R.; Salata, Michael J.; Cupp, Sean A.; Sheehan, Joseph; Voos, James E.

    2016-01-01

    Context: Wearable performance devices and sensors are becoming more readily available to the general population and athletic teams. Advances in technology have allowed individual endurance athletes, sports teams, and physicians to monitor functional movements, workloads, and biometric markers to maximize performance and minimize injury. Movement sensors include pedometers, accelerometers/gyroscopes, and global positioning satellite (GPS) devices. Physiologic sensors include heart rate monitors, sleep monitors, temperature sensors, and integrated sensors. The purpose of this review is to familiarize health care professionals and team physicians with the various available types of wearable sensors, discuss their current utilization, and present future applications in sports medicine. Evidence Acquisition: Data were obtained from peer-reviewed literature through a search of the PubMed database. Included studies searched development, outcomes, and validation of wearable performance devices such as GPS, accelerometers, and physiologic monitors in sports. Study Design: Clinical review. Level of Evidence: Level 4. Results: Wearable sensors provide a method of monitoring real-time physiologic and movement parameters during training and competitive sports. These parameters can be used to detect position-specific patterns in movement, design more efficient sports-specific training programs for performance optimization, and screen for potential causes of injury. More recent advances in movement sensors have improved accuracy in detecting high-acceleration movements during competitive sports. Conclusion: Wearable devices are valuable instruments for the improvement of sports performance. Evidence for use of these devices in professional sports is still limited. Future developments are needed to establish training protocols using data from wearable devices. PMID:26733594

  12. Pointing Device Performance in Steering Tasks.

    PubMed

    Senanayake, Ransalu; Goonetilleke, Ravindra S

    2016-06-01

    Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants aged 20.1 ± 3.13 years. It was found that, depending on the difficulty of the task, the optimal settings differ for ballistic and visual control tasks. With a touch screen, resting the arm increased movement time for steering tasks. When both performance and comfort are considered, whether to use a mouse or a touch screen for person-computer interaction depends on the steering difficulty. Hence, a input device should be chosen based on the application, and should be optimized to match the graphical user interface.

  13. Reporting performance in organic photovoltaic devices.

    PubMed

    Luber, Erik J; Buriak, Jillian M

    2013-06-25

    Research into organic photovoltaics (OPVs) is rapidly growing worldwide because it offers a route to low temperature, inexpensive processing of lightweight, flexible solar cells that can be mass manufactured cheaply. Unlike silicon or other inorganic semiconductors (e.g., CdTe, CIGs), OPVs are complicated by the requirement of having multiple materials and layers that must be integrated to enable the cell to function. The enormous number of research hours required to optimize all aspects of OPVs and to integrate them successfully is typically boiled down to one number-the power conversion efficiency (PCE) of the device. The PCE is the value by which comparisons are routinely made when modifications are made to devices; new bulk heterojunction materials, electron- and hole-transport layers, electrodes, plasmonic additives, and many other new advances are incorporated into OPV devices and compared with one, or a series of, control device(s). The concern relates to the statistical significance of this all-important efficiency/PCE value: is the observed change or improvement in performance truly greater than experimental error? If it is not, then the field can and will be misled by improper reporting of efficiencies, and future research in OPVs could be frustrated and, ultimately, irreversibly damaged. In this Perspective, the dangers of, for instance, cherry-picking of data and poor descriptions of experimental procedures, are outlined, followed by a discussion of a real data set of OPV devices, and how a simple and easy statistical treatment can help to distinguish between results that are indistinguishable experimentally, and those that do appear to be different.

  14. Substrate influences on CIS device performance

    SciTech Connect

    Dawson-Elli, D.F.; Moore, C.B.; Gay, R.R.; Jensen, C.L.

    1994-12-31

    It has been reported that the substrate plays an active role in copper indium diselenide (CIS) devices. The physical properties of the substrate, i.e., thermal expansion coefficient, chemical composition, strain point, surface quality and cleanliness may all play a role in device efficiency and process reproducibility. For example, sodium is known to influence the conductivity of CIS, and that soda lime glass (SLG) introduces sodium into the CIS. In the experiments reported here, the sodium level in the CIS was varied by (a) changing the substrate composition and (b) the use of SiO{sub x}N{sub y} and SiN{sub x} barrier layers. Cells were fabricated on the candidate substrate and barrier layer combinations. V{sub oc} was observed to drop with the addition of barrier layers to sodium containing glasses. The films were also analyzed for sodium by SIMS. The cell performance and SIMS analysis are presented and their significance is discussed.

  15. High performance flexible electronics for biomedical devices.

    PubMed

    Salvatore, Giovanni A; Munzenrieder, Niko; Zysset, Christoph; Kinkeldei, Thomas; Petti, Luisa; Troster, Gerhard

    2014-01-01

    Plastic electronics is soft, deformable and lightweight and it is suitable for the realization of devices which can form an intimate interface with the body, be implanted or integrated into textile for wearable and biomedical applications. Here, we present flexible electronics based on amorphous oxide semiconductors (a-IGZO) whose performance can achieve MHz frequency even when bent around hair. We developed an assembly technique to integrate complex electronic functionalities into textile while preserving the softness of the garment. All this and further developments can open up new opportunities in health monitoring, biotechnology and telemedicine.

  16. Microscale Confinement features in microfluidic devices can affect biofilm

    SciTech Connect

    Kumar, Aloke; Karig, David K; Neethirajan, Suresh; Acharya, Rajesh K; Mukherjee, Partha P; Retterer, Scott T; Doktycz, Mitchel John

    2013-01-01

    Biofilms are aggregations of microbes that are encased by extra-cellular polymeric substances (EPS) and adhere to surfaces and interfaces. Biofilm development on abiotic surfaces is a dynamic process, which typically proceeds through an initial phase of adhesion of plankntonic microbes to the substrate, followed by events such as growth, maturation and EPS secretion. However, the coupling of hydrodynamics, microbial adhesion and biofilm growth remain poorly understood. Here, we investigate the effect of semiconfined features on biofilm formation. Using a microfluidic device and fluorescent time-lapse microscopy, we establish that confinement features can significantly affect biofilm formation. Biofilm dynamics change not only as a function of confinement features, but also of the total fluid flow rate, and our combination of experimental results and numerical simulations reveal insights into the link between hydrodynamics and biofilm formation.

  17. Performance of superconducting microwave devices passivated with dielectric materials

    SciTech Connect

    Henderson, M.L.; Kohl, P.A.; Eddy, M.M.; Zuck, B.F.

    1997-09-01

    We present a set of experiments which show that three dielectric processing variables in particular affect the performance of superconducting microwave devices: processing time and temperature, moisture content of the dielectric material, and surface interactions with the high temperature superconductor (HTS). The changes in microwave performance of a straight-line microstrip resonator before and after passivation were quantified by measurements of the loaded and unloaded quality factors for each resonator. Dielectric materials of varying moisture content were used. The dielectrics were processed at different times and temperatures. This study shows that the degradation of the microwave devices can be minimized by choosing dielectrics which (i) have a low moisture content, (ii) interact as little as possible with the HTS surface, and (iii) can be rapidly processed at relatively low temperatures. {copyright} {ital 1997 American Institute of Physics.}

  18. Performance of GPS-devices for environmental exposure assessment.

    PubMed

    Beekhuizen, Johan; Kromhout, Hans; Huss, Anke; Vermeulen, Roel

    2013-01-01

    Integration of individual time-location patterns with spatially resolved exposure maps enables a more accurate estimation of personal exposures to environmental pollutants than using estimates at fixed locations. Current global positioning system (GPS) devices can be used to track an individual's location. However, information on GPS-performance in environmental exposure assessment is largely missing. We therefore performed two studies. First, a commute-study, where the commute of 12 individuals was tracked twice, testing GPS-performance for five transport modes and two wearing modes. Second, an urban-tracking study, where one individual was tracked repeatedly through different areas, focused on the effect of building obstruction on GPS-performance. The median error from the true path for walking was 3.7 m, biking 2.9 m, train 4.8 m, bus 4.9 m, and car 3.3 m. Errors were larger in a high-rise commercial area (median error=7.1 m) compared with a low-rise residential area (median error=2.2 m). Thus, GPS-performance largely depends on the transport mode and urban built-up. Although ~85% of all errors were <10 m, almost 1% of the errors were >50 m. Modern GPS-devices are useful tools for environmental exposure assessment, but large GPS-errors might affect estimates of exposures with high spatial variability.

  19. US FDA perspective on regulatory issues affecting circulatory assist devices.

    PubMed

    Sapirstein, Wolf; Chen, Eric; Swain, Julie; Zuckerman, Bram

    2006-11-01

    There has been a rapid development in mechanical circulatory support systems in the decade since the US FDA first approved a mechanical device to provide the circulatory support lacking from a failing heart. Devices are presently approved for marketing by the FDA to replace a failing ventricle, the Ventricular Assist Device or the entire heart, Total Artificial Heart. Contemporaneous with, and permitted by, improvement in technology and design, devices have evolved from units located extracorporeally to paracorporeal systems and totally implanted devices. Clinical studies have demonstrated a parallel improvement in the homeostatic adequacy of the circulatory support provided. Thus, while the circulatory support was initially tolerated for short periods to permit recovery of cardiac function, this technology eventually provided effective circulatory support for increasing periods that permitted the FDA to approve devices for bridging patients in end-stage cardiac failure awaiting transplant and eventually a device for destination therapy where patients in end-stage heart failure are not cardiac transplant candidates. The approved devices have relied on displacement pumps that mimic the pulsatility of the physiological system. Accelerated development of more compact devices that rely on alternative pump mechanisms have challenged both the FDA and device manufacturers to assure that the regulatory requirements for safety and effectiveness are met for use of mechanical circulatory support systems in expanded target populations. An FDA regulatory perspective is reviewed of what can be a potentially critical healthcare issue.

  20. Microfabricated devices for performing chemical and biochemical analysis

    SciTech Connect

    Ramsey, J.M.; Jacobson, S.C.; Foote, R.S.

    1997-05-01

    There is growing interest in microfabricated devices that perform chemical and biochemical analysis. The general goal is to use microfabrication tools to construct miniature devices that can perform a complete analysis starting with an unprocessed sample. Such devices have been referred to as lab-on-a-chip devices. Initial efforts on microfluidic laboratory-on-a-chip devices focused on chemical separations. There are many potential applications of these fluidic microchip devices. Some applications such as chemical process control or environmental monitoring would require that a chip be used over an extended period of time or for many analyses. Other applications such as forensics, clinical diagnostics, and genetic diagnostics would employ the chip devices as single use disposable devices.

  1. On performing semantic queries in small devices

    NASA Astrophysics Data System (ADS)

    Costea, C.; Petrovan, A.; Neamţ, L.; Chiver, O.

    2016-08-01

    The sensors have a well-defined role in control or monitoring industrial processes; the data given by them can generate valuable information of the trend of the systems to which they belong, but to store a large volume of data and then analysis offline is not always practical. One solution is on-line analysis, preferably as close to the place where data have been generated (edge computing). An increasing amount of data generated by a growing number of devices connected to the Internet resulted in processing data sensors to the edge of the network, in a middle layer where smart entities should interoperate. Diversity of communication technologies outlined the idea of using intermediate devices such as gateways in sensor networks and for this reason the paper examines the functionality of a SPARQL endpoint in the Raspberry Pi device.

  2. PERFORMANCE EVALUATION OF TYPE I MARINE SANITATION DEVICES

    EPA Science Inventory

    This performance test was designed to evaluate the effectiveness of two Type I Marine Sanitation Devices (MSDs): the Electro Scan Model EST 12, manufactured by Raritan Engineering Company, Inc., and the Thermopure-2, manufactured by Gross Mechanical Laboratories, Inc. Performance...

  3. Living with Smartphones: Does Completion Device Affect Survey Responses?

    ERIC Educational Resources Information Center

    Lambert, Amber D.; Miller, Angie L.

    2015-01-01

    With the growing reliance on tablets and smartphones for internet access, understanding the effects of completion device on online survey responses becomes increasing important. This study uses data from the Strategic National Arts Alumni Project, a multi-institution online alumni survey designed to obtain knowledge of arts education, to explore…

  4. How Mobile Devices Affect Students According to Teachers' Beliefs

    ERIC Educational Resources Information Center

    Cumaoglu, Gonca Kizilkaya

    2015-01-01

    The purpose of this study is to examine teachers' beliefs concerning the effects on students using mobile devices, and to determine whether these beliefs vary according to the demographic characteristics and Internet usage purposes. For this purpose, a demographic information questionnaire and the scale developed by Diker Coskun & Kizilkaya…

  5. Attribution, Affect, and College Exam Performance.

    ERIC Educational Resources Information Center

    Arkin, Robert M.; Maruyama, Geoffrey M.

    1979-01-01

    College students attributed their own performance and the performance of the average student to ability, test difficulty, preparation, and luck. Successful students perceived internal factors and unsuccessful students perceived external factors as more important causes of their own performance. Students' anxiety and their ratings of the course and…

  6. Performance Gains of Propellant Management Devices for Liquid Hydrogen Depots

    NASA Technical Reports Server (NTRS)

    Hartwig, Jason W.; McQuillen, John B.; Chato, David J.

    2013-01-01

    This paper presents background, experimental design, and preliminary experimental results for the liquid hydrogen bubble point tests conducted at the Cryogenic Components Cell 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. The purpose of the test series was to investigate the parameters that affect liquid acquisition device (LAD) performance in a liquid hydrogen (LH2) propellant tank, to mitigate risk in the final design of the LAD for the Cryogenic Propellant Storage and Transfer Technology Demonstration Mission, and to provide insight into optimal LAD operation for future LH2 depots. Preliminary test results show an increase in performance and screen retention over the low reference LH2 bubble point value for a 325 2300 screen in three separate ways, thus improving fundamental LH2 LAD performance. By using a finer mesh screen, operating at a colder liquid temperature, and pressurizing with a noncondensible pressurant gas, a significant increase in margin is achieved in bubble point pressure for LH2 screen channel LADs.

  7. Testing Devices Garner Data on Insulation Performance

    NASA Technical Reports Server (NTRS)

    2014-01-01

    To develop a test instrument that could garner measurements of the thermal performance of insulation under extreme conditions, researchers at Kennedy Space Center devised the Cryostat 1 and then Cryostat 2. McLean, Virginia-based QinetiQ North America licensed the technology and plans to market it to organizations developing materials for things like piping and storage tank insulation, refrigeration, appliances, and consumer goods.

  8. Performance of selected flow-restricting infusion devices.

    PubMed

    Capes, D F; Asiimwe, D

    1998-02-15

    The flow rate accuracy and flow continuity of the Homepump, Infusor, Intermate, Paragon, Sidekick, and Springfusor 10 flow-restricting infusion devices were studied. Three of each device were tested in a temperature-controlled cabinet at the manufacturer-specified operating temperature and at 20 and 30 degrees C. The flow rates used were 100 ml/hr and the rate that would provide a 24-hour delivery of fluid, except in the case of the Springfusor 10, which was tested at the maximum and minimum flow rates. Flow rate was measured gravimetrically at 30-second intervals. The endopoint of infusion was defined as the start of the terminal-phase decline. The effect of refrigerated storage was studied by using the Intermate as an example of the elastomeric devices tested. All devices exhibited a variable flow profile during infusion except for the Paragon, which had a near-constant flow throughout. The average error in flow rate was within the manufacturer's specifications when the devices were used under the manufacturer-specified operating conditions for all devices except for the Sidekick. The definition of the endopoint made little difference in the flow rate results for the Infusor and Springfusor 10 but significantly affected the flow rate results for the other devices, for which there was a substantial terminal phase with a prolonged period of reduced flow rate. The mean flow rate, error, and coefficient of variation for the Intermate devices stored under refrigeration were significantly different from those for the devices not refrigerated before use. When operated as recommended by the manufacturer, five of six devices had a flow rate error within the manufacturer's specifications; the results were affected by endpoint definition.

  9. Carbon nanotube-enhanced performance of microplasma devices

    NASA Astrophysics Data System (ADS)

    Park, S.-J.; Eden, J. G.; Park, K.-H.

    2004-05-01

    Incorporating multiwall carbon nanotubes (CNTs) directly into the cylindrical cathode of Ni screen/BN/Ni microplasma devices significantly improves all device performance parameters—operating and ignition voltages, as well as radiative efficiency. Having a cathode diameter of 200 μm, these devices exhibit operating voltages as much as 30 V (˜22%) lower than those required for an identical structure without CNTs. For Ne pressures of 100-300 Torr, ignition voltages are reduced by 14%-18% with the introduction of CNTs. In contrast, radiative efficiencies in the 300-800 nm spectral region are increased with CNTs by 6%-9% over the entire pressure range studied (200-600 Torr Ne). Voltage-current characteristics for two device configurations suggest that electrons generated within the cathode microcavity by CNT field emission are most effective in impacting device performance.

  10. Locomotion Performance of Biomimetic Fish-like Swimming Devices

    NASA Astrophysics Data System (ADS)

    Epps, Brenden P.; Valdivia Y Alvarado, Pablo; Techet, Alexandra H.

    2007-11-01

    The swimming performance of a biomimetic, fish-like swimming device, designed to exploit the natural dynamics of its compliant body to achieve locomotion, is studied experimentally. A theoretical model combines beam-bending stress analysis and unsteady hydrodynamic forcing with known material properties of the robot to reveal desired geometry distributions and actuation modes. Swimming kinematics and corresponding performance of the device are also predicted and tested for a carangiform prototype device in a quiescent tank of water. Experimental swimming tests show good agreement with the simplified theoretical models. The hydrodynamic characteristics of the wake behind the device are investigated using time-resolved particle imaging velocimetry (PIV) over a range of tail beat frequencies, from 1 to 4 Hz, to asses vortical wake patterns and hydrodynamic forces. PIV data are compared to theoretical model predictions. Reynolds numbers for the swimming device are between 2500 and 8500 based on body length.

  11. New high performance Si for optical devices

    NASA Astrophysics Data System (ADS)

    Tenma, T.; Matsuzaka, M.; Sako, R.; Takase, K.; Chiba, K.

    2016-05-01

    Against the backdrop of a growing demand in the areas of smart buildings, security, vehicle installation, and other applications, the market for far infrared cameras is expected to grow significantly in the future. However, since germanium (Ge) and chalcogenide glass, which have been used as the lens materials of far infrared cameras, are very expensive or highly toxic, there are some problems supporting the growing demand. We have therefore focused attention on silicon, which is inexpensive and less toxic. Although silicon has been used as a lens material of far infrared cameras, there are some problems remaining to be solved: Cz silicon is inexpensive but delivers low transmittance, and Fz silicon delivers sufficient transmittance but is expensive. We have developed New Cz silicon, which delivers high transmittance as Fz silicon does, and is inexpensive as conventional Cz silicon is. We have already started its sample work at both companies in Japan and overseas and have obtained excellent performance results. Mass production is scheduled to start in this fiscal year.

  12. Molecular materials for high performance OPV devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Jones, David J.

    2016-09-01

    We recently reported the high performing molecular donor for OPV devices based on a benzodithiophene core, a terthiophene bridge and a rhodamine acceptor (BTR) [1]. In this work we optimized side-chain placement of a known chromophore by ensuring the thiophene hexyl side-chains are regioregular, which should allow the chromophore to lie flat. The unexpected outcome was a nematic liquid crystalline material with significantly improved performance (now 9.6% PCE), excellent charge transport properties, reduced geminate recombination rates and excellent performance with active layers up to 400nm. Three phase changes were indicated by DSC analysis with a melt to a crystalline domain at 175 oC, transition to a nematic liquid crystalline domain at 186 oC and an isotropic melt at 196 oC. In our desire to better understand the structure property relationships of this class of p-type organic semiconductor we have synthesized a series of analogues where the length of the chromophore has been altered through modification of the oligothiophene bridge to generate, the monothiophene (BMR), the bisthiophene (BBR), the known terthiophene (BTR), the quaterthiophene (BQR) and the pentathiophene (BPR). BMR, BBR and BPR have clean melting points while BQR, like BTR shows a complicated series of phase transitions. Device efficiencies after solvent vapour annealing are BMR (3.5%), BBR (6.0%), BTR (9.3%), BQR (9.4%), and BPR (8.7%) unoptimised. OPV devices with BTR in the active layer are not stable under thermal annealing, however the bridge extended BQR and BPR form thermally stable devices. We are currently optimising these devices, but initial results indicate PCEs >9% for thermally annealed devices containing BQR, while BPR devices have not yet been optimised and have PCEs > 8%. In order to develop the device performance we have included BQR in ternary devices with the commercially available PTB7-Th and we report device efficiencies of over 10.5%. We are currently optimising device

  13. Device Engineering Towards Improved Tin Sulfide Solar Cell Performance and Performance Reproducibility

    SciTech Connect

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul; Siol, Sebastian; Martinot, Loic; Polizzotti, Alex; Yang, Chuanxi; Hartman, Katy; Gradecak, Silvija; Zakutayev, Andriy; Gordon, Roy G.; Buonassisi, Tonio

    2016-11-21

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to rapidly test promising candidates in high-performing PV devices. There is a need to engineer new compatible device architectures, including the development of novel transparent conductive oxides and buffer layers. Here, we consider the two approaches of a substrate-style and a superstrate-style device architecture for novel thin-film solar cells. We use tin sulfide as a test absorber material. Upon device engineering, we demonstrate new approaches to improve device performance and performance reproducibility.

  14. Critical process parameters affecting zincrometal performance

    SciTech Connect

    Iezzi, R.A.

    1984-01-01

    A laboratory study aimed at improving the corrosion resistance of Zincrometal has shown that excellent Zincrometal performance in laboratory corrosion tests can be obtained by achieving a trivalent (Cr+3) to hexavalent (Cr+6) Dacromet chromium ratio of at least 15. Increasing thermal energy input during curing increases the Cr+3/Cr+6 ratio and improves corrosion resistance in laboratory tests. Increasing curing energy input in production may be a viable approach to improve Zincrometal performance, provided that steels not susceptible to strain aging are used.

  15. Factors Affecting Information Literacy Perception and Performance

    ERIC Educational Resources Information Center

    Zehner, Drusilla Charlene Beecher

    2009-01-01

    Information literacy, defined as, "the set of skills needed to find, retrieve, analyze, and use information" (American Library Association, 2003, paragraph 1), is necessary for success in life. The present study will examine whether the factors of gender, race, and/or socioeconomic status impact information literacy performance and…

  16. Factors affecting penetrating captive bolt gun performance.

    PubMed

    Gibson, Troy J; Mason, Charles W; Spence, Jade Y; Barker, Heather; Gregory, Neville G

    2015-01-01

    Captive bolt stunning is used for rendering livestock insensible at slaughter. The mechanical factors relating to performance of 6 penetrating captive bolt gun (CBG) models were examined. The Matador Super Sécurit 3000 and the .25 Cash Euro Stunner had the highest kinetic energy values (443 J and 412 J, respectively) of the CBGs tested. Ninety percent (27/30) of CBGs held at a government gun repository (United Kingdom) were found to have performed at a normal standard for the model, while 53% (10/19) of commercial contractor CBGs tested were found to underperform for the gun model. When the .22 Cash Special was fired 500 times at 4 shots per min, the gun reached a peak temperature of 88.8°C after 2.05 hr. Repeat firing during extended periods significantly reduced the performance of the CBG. When deciding on the appropriate CBG/cartridge combination, the kinetic energy delivered to the head of the nonhuman animal, bolt penetration depth, and species/animal type must be considered. It is recommended that CBGs are routinely checked for wear to the bolt and barrel if they are repeatedly fired in a session.

  17. Does posttraumatic stress disorder (PTSD) affect performance?

    PubMed

    LeBlanc, Vicki R; Regehr, Cheryl; Jelley, R Blake; Barath, Irene

    2007-08-01

    Research has increasingly identified alarming levels of traumatic stress symptoms in individuals working in emergency services and other high stress jobs. This study examined the effects of prior critical incident exposure and current posttraumatic symptoms on the performance of a nonpatient population, police recruits, during an acutely stressful event. A stressful policing situation was created through the use of a video simulator room that was responsive to actions of participants. The performance of participants to the simulated emergency was evaluated by 3 independent blinded raters. Prior exposure to critical incidents was measured using the Critical Incident History Questionnaire and current level of traumatic stress symptoms was measured using the Impact of Events Scale-Revised. Neither previous exposure to critical incidents nor trauma symptoms correlated with performance level. Recruits with high or severe levels of trauma symptoms did not demonstrate impairments in judgment, communication, or situation control compared with their colleagues with lesser or no trauma symptoms. On the basis of these findings, there is no reason to believe that police recruits with PTSD are prone to making errors of communication or judgment that would place them or others at increased risk.

  18. Performance capabilities of fiber optic components and photonic devices

    NASA Astrophysics Data System (ADS)

    Jha, Asu R.

    2001-09-01

    This paper reveals performance capabilities of critical fiber optic components and photonic devices, which have potential applications in industrial, commercial and military systems and equipment. These devices are widely used in battlefield, space surveillance, medical diagnosis, crime fighting, and detection of terrorist activities. Performance capabilities of fiber optic components for possible applications in WDM and DWDM systems are summarized. Photonic devices and sensor for forward battlefield applications are identified with emphasis on performance and reliability. Performance parameters of Erbium-doped fiber amplifiers, Erbium doped waveguide amplifiers, and optical hybrid amplifiers comprising of EDFAs and Raman amplifiers are discussed withe emphasis on bandwidth, gain-flatness, data handling capability, channel capacity and cost-effectiveness.

  19. Performance of a capillary propellant management device with hydrazine

    NASA Technical Reports Server (NTRS)

    Tegart, J. R.

    1979-01-01

    The propellant management device that was successfully used in the Viking Orbiter spacecraft was selected for the main propulsion system of the Teleoperator Retrieval System (TRS). Due to differences in the missions and different propellants, the operation of this sheet metal vane device required reverification for the TRS application. An analytical investigation was performed considering the adverse acceleration environment and the high contract angle of the hydrazine propellant. Drop tower tests demonstrated that the device would provide propellant acquisition while the TRS was docked with Skylab, but its operation would have to be supplemented through propellant settling when free-flying.

  20. Infants' Understanding of Actions Performed by Mechanical Devices

    ERIC Educational Resources Information Center

    Boyer, Ty W.; Pan, J. Samantha; Bertenthal, Bennett I.

    2011-01-01

    Recent research suggests that 9-month-old infants tested in a modified version of the A-not-B search task covertly imitate actions performed by the experimenter. The current study examines whether infants also simulate actions performed by mechanical devices, and whether this varies with whether or not they have been familiarized with the devices…

  1. Silicon Carbide Diodes Performance Characterization and Comparison With Silicon Devices

    NASA Technical Reports Server (NTRS)

    Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Trapp, Scott

    2003-01-01

    Commercially available silicon carbide (SiC) Schottky diodes from different manufacturers were electrically tested and characterized at room temperature. Performed electrical tests include steady state forward and reverse I-V curves, as well as switching transient tests performed with the diodes operating in a hard switch dc-to-dc buck converter. The same tests were performed in current state of the art silicon (Si) and gallium arsenide (GaAs) Schottky and pn junction devices for evaluation and comparison purposes. The SiC devices tested have a voltage rating of 200, 300, and 600 V. The comparison parameters are forward voltage drop at rated current, reverse current at rated voltage and peak reverse recovery currents in the dc to dc converter. Test results show that steady state characteristics of the tested SiC devices are not superior to the best available Si Schottky and ultra fast pn junction devices. Transient tests reveal that the tested SiC Schottky devices exhibit superior transient behavior. This is more evident at the 300 and 600 V rating where SiC Schottky devices showed drastically lower reverse recovery currents than Si ultra fast pn diodes of similar rating.

  2. Body position affects performance in untrained cyclists

    PubMed Central

    Ashe, M; Scroop, G; Frisken, P; Amery, C; Wilkins, M; Khan, K

    2003-01-01

    Objective: To compare cardiovascular and ventilatory variables in upright versus aero cycle ergometry at submaximal and maximal exercise intensities in untrained cyclists. Method: Ten physically active men (mean (SD) age 19.1 (1.10) years) who were unfamiliar with aerobars underwent maximal exercise testing and steady state cycling at 50, 100, and 150 W. Results: Participants had significantly greater maxima for oxygen uptake (VO2), ventilation, heart rate, and workload maximum in the upright position. During steady state cycling at the three workloads, VO2 (ml/kg/min) and gross mechanical efficiency were significantly greater in the upright position. Conclusions: In untrained subjects performing with maximal effort, the upright position permits greater VO2, ventilation, heart rate, and workload maxima. Further, in the steady state, exercise cycling may be less costly in the upright position. For this reason, untrained cyclists need to weigh body position effects against the well known aerodynamic advantages of the aero position. PMID:14514538

  3. Digital Devices, Distraction, and Student Performance: Does In-Class Cell Phone Use Reduce Learning?

    ERIC Educational Resources Information Center

    Duncan, Douglas K.; Hoekstra, Angel R.; Wilcox, Bethany R.

    2012-01-01

    The recent increase in use of digital devices such as laptop computers, iPads, and web-enabled cell phones has generated concern about how technologies affect student performance. Combining observation, survey, and interview data, this research assesses the effects of technology use on student attitudes and learning. Data were gathered in eight…

  4. High voltage stability performance of a gamma ray detection device

    NASA Astrophysics Data System (ADS)

    Abdullah, Nor Arymaswati; Lombigit, Lojius; Rahman, Nur Aira Abd

    2014-02-01

    An industrial grade digital radiation survey meter device is currently being developed at Malaysian Nuclear Agency. This device used a cylindrical type Geiger Mueller (GM) which acts as a detector. GM detector operates at relatively high direct current voltages depend on the type of GM tube. This thin/thick walled cylindrical type of GM tube operates at 450-650 volts range. Proper value and stability performance of high voltage are important parameters to ensure that this device give a reliable radiation dose measurement. This paper will present an assessment of the stability and performance of the high voltage supply for radiation detector. The assessment is performed using System Identification tools box in MATLAB and mathematical statistics.

  5. High voltage stability performance of a gamma ray detection device

    SciTech Connect

    Abdullah, Nor Arymaswati; Lombigit, Lojius; Rahman, Nur Aira Abd

    2014-02-12

    An industrial grade digital radiation survey meter device is currently being developed at Malaysian Nuclear Agency. This device used a cylindrical type Geiger Mueller (GM) which acts as a detector. GM detector operates at relatively high direct current voltages depend on the type of GM tube. This thin/thick walled cylindrical type of GM tube operates at 450-650 volts range. Proper value and stability performance of high voltage are important parameters to ensure that this device give a reliable radiation dose measurement. This paper will present an assessment of the stability and performance of the high voltage supply for radiation detector. The assessment is performed using System Identification tools box in MATLAB and mathematical statistics.

  6. Scaling of Performance in Liquid Propellant Rocket Engine Combustion Devices

    NASA Technical Reports Server (NTRS)

    Hulka, James R.

    2008-01-01

    This paper discusses scaling of combustion and combustion performance in liquid propellant rocket engine combustion devices. In development of new combustors, comparisons are often made between predicted performance in a new combustor and measured performance in another combustor with different geometric and thermodynamic characteristics. Without careful interpretation of some key features, the comparison can be misinterpreted and erroneous information used in the design of the new device. This paper provides a review of this performance comparison, including a brief review of the initial liquid rocket scaling research conducted during the 1950s and 1960s, a review of the typical performance losses encountered and how they scale, a description of the typical scaling procedures used in development programs today, and finally a review of several historical development programs to see what insight they can bring to the questions at hand.

  7. Spectroradiometer Intercomparison and Impact on Characterizing Photovoltaic Device Performance: Preprint

    SciTech Connect

    Habte, A.; Andreas, A.; Ottoson, L.; Gueymard, C.; Fedor, G.; Fowler, S.; Peterson, J.; Naranen, E.; Kobashi, T.; Akiyama, A.; Takagi, S.

    2014-11-01

    Indoor and outdoor testing of photovoltaic (PV) device performance requires the use of solar simulators and natural solar radiation, respectively. This performance characterization requires accurate knowledge of spectral irradiance distribution that is incident on the devices. Spectroradiometers are used to measure the spectral distribution of solar simulators and solar radiation. On September 17, 2013, a global spectral irradiance intercomparison using spectroradiometers was organized by the Solar Radiation Research Laboratory (SRRL) at the National Renewable Energy Laboratory (NREL). This paper presents highlights of the results of this first intercomparison, which will help to decrease systematic inter-laboratory differences in the measurements of the outputs or efficiencies of PV devices and harmonize laboratory experimental procedures.

  8. Towards Non-thrombogenic Performance of Blood Recirculating Devices

    PubMed Central

    Bluestein, D.; Chandran, K. B.; Manning, K. B.

    2010-01-01

    Implantable blood recirculating devices have provided life saving solutions to patients with severe cardiovascular diseases. However, common problems of hemolysis and thromboembolism remain an impediment to these devices. In this article, we present a brief review of the work by several groups in the field that has led to the development of new methodologies that may facilitate achieving the daunting goal of optimizing the thrombogenic performance of blood recirculating devices. The aim is to describe work which pertains to the interaction between flow-induced stresses and the blood constituents, and that supports the hypothesis that thromboembolism in prosthetic blood recirculating devices is initiated and maintained primarily by the non-physiological flow patterns and stresses that activate and enhance the aggregation of blood platelets, increasing the risk of thromboembolism and cardioembolic stroke. Such work includes state-of-the-art numerical and experimental tools used to elucidate flow-induced mechanisms leading to thromboembolism in prosthetic devices. Following the review, the paper describes several efforts conducted by some of the groups active in the field, and points to several directions that should be pursued in the future in order to achieve the goal for blood recirculating prosthetic devices becoming more effective as destination therapy in the future. PMID:20131098

  9. Performance optimization of a pneumatic wave energy conversion device

    NASA Astrophysics Data System (ADS)

    Surko, S. W.

    1982-08-01

    The purpose of this study was, for the first time, to optimize the performance of a pneumatic wave energy conversion device. The experiments of Jolly and Newmaster (1979) and Trop and Casey (1980) left a capture chamber and turbine for further investigation. To optimize the system performance the turbine had to be first analyzed so that its power performance curves could be determined. These curves were needed to help define the possible overall performance of the system, and for the impedance matching of the system necessary for performance optimization. With this knowledge, an appropriate generator was purchased and a generator-turbine linkage designed and built. The completed system was then analyzed in the 380 ft wave tank at the U.S. Naval Academy to establish its optimum performance. From the research it is clear that pneumatic wave energy conversion is a promising concept. With several hundred of these devices situated some 100 km off the coast of the Pacific Northwest each device would be producing from 50 to 200 kW which would be transferred back to shore.

  10. Optimal combination of auxiliary device size and its location on chopsticks for food-gripping performances.

    PubMed

    Lee, Yu-Chi; Chen, Yi-Lang

    2012-08-01

    Chopsticks are the main utensils for daily dining in Asia. Lee and Chen (2008) designed a novel auxiliary device for chopsticks that successfully converts people experienced in scissor-pinching to the correct method: pincer-pinching. This study attempts to assess the optimal combination of auxiliary size and location on chopstick stems for food-gripping performance. Twenty-four male participants experienced in scissor-pinching were recruited for the experiment. They were requested to perform 3 simulated tasks (force, precision, and stability) using 6 auxiliary combinations of 3 sizes (15, 25, and 35 mm) of chopsticks and 2 locations (on top of the stems and 1/3 stem-length from the top). Results indicate that auxiliary device size influenced simulated task performance and the user's subjective rating of chopsticks use. The auxiliary device measuring 15 mm wide showed the best performance in pinching force, precision, stability, and subjective rating. The location of the auxiliary device only affected the pinching force. The auxiliary device produced greater force when located at the top of the stems. This finding improves the application of auxiliary devices to chopstick operation.

  11. Si-photonics based passive device packaging and module performance.

    PubMed

    Song, Jeong Hwan; Zhang, Jing; Zhang, Huijuan; Li, Chao; Lo, Guo Qiang

    2011-09-12

    We report a fully packaged silicon passive waveguide device designed for a tunable filter based on a ring-resonator. Polarization diversity circuits prevent polarization dependant issues in the silicon ring-resonator. For the device packaging, the YAG laser welding technique has been used for pigtailing both of the input and output fibers. Post welding misalignment was compensated by mechanical fine tuning using the seesaw effect via power monitoring. Packaging loss less than 1.5 dB with respect to chip measurement has been achieved using 10 µm-curvature radius lensed fibers. In addition, the packaging process and the module performance are presented.

  12. Medical Device Risk Management For Performance Assurance Optimization and Prioritization.

    PubMed

    Gaamangwe, Tidimogo; Babbar, Vishvek; Krivoy, Agustina; Moore, Michael; Kresta, Petr

    2015-01-01

    Performance assurance (PA) is an integral component of clinical engineering medical device risk management. For that reason, the clinical engineering (CE) community has made concerted efforts to define appropriate risk factors and develop quantitative risk models for efficient data processing and improved PA program operational decision making. However, a common framework that relates the various processes of a quantitative risk system does not exist. This article provides a perspective that focuses on medical device quality and risk-based elements of the PA program, which include device inclusion/exclusion, schedule optimization, and inspection prioritization. A PA risk management framework is provided, and previous quantitative models that have contributed to the advancement of PA risk management are examined. A general model for quantitative risk systems is proposed, and further perspective on possible future directions in the area of PA technology is also provided.

  13. Physics and performance of nanoscale semiconductor devices at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Balestra, F.; Ghibaudo, G.

    2017-02-01

    The physics and performance of various advanced semiconductor devices, which are the most promising for the end of the ITRS roadmap, are investigated in a wide temperature range down to 20 K. The transport parameters in front and/or back channels in fully depleted ultrathin film SOI devices, Trigate, FinFET, Omega-gate nanowire FET and 3D-stacked SiGe nanowire FETs, fabricated with high-k dielectrics/metal gate, elevated source/drain, different channel orientations, shapes and strains, are addressed. The impacts of the gate length, Si film and wire diameter down to 10 nm, are also shown. The variations of the phonon, Coulomb, neutral defects and surface roughness scattering as a function of temperature and device architecture are highlighted. An overview of the influence of temperature on other main electrical parameters of MOSFETs, nanowires FETs and tunnel FETs, such as threshold voltage, subthreshold swing, leakage and driving currents is also given.

  14. Performance processes within affect-related performance zones: a multi-modal investigation of golf performance.

    PubMed

    van der Lei, Harry; Tenenbaum, Gershon

    2012-12-01

    Individual affect-related performance zones (IAPZs) method utilizing Kamata et al. (J Sport Exerc Psychol 24:189-208, 2002) probabilistic model of determining the individual zone of optimal functioning was utilized as idiosyncratic affective patterns during golf performance. To do so, three male golfers of a varsity golf team were observed during three rounds of golf competition. The investigation implemented a multi-modal assessment approach in which the probabilistic relationship between affective states and both, performance process and performance outcome, measures were determined. More specifically, introspective (i.e., verbal reports) and objective (heart rate and respiration rate) measures of arousal were incorporated to examine the relationships between arousal states and both, process components (i.e., routine consistency, timing), and outcome scores related to golf performance. Results revealed distinguishable and idiosyncratic IAPZs associated with physiological and introspective measures for each golfer. The associations between the IAPZs and decision-making or swing/stroke execution were strong and unique for each golfer. Results are elaborated using cognitive and affect-related concepts, and applications for practitioners are provided.

  15. Methods for validating the performance of wearable motion-sensing devices under controlled conditions

    NASA Astrophysics Data System (ADS)

    Bliley, Kara E; Kaufman, Kenton R; Gilbert, Barry K

    2009-04-01

    This paper presents validation methods for assessing the accuracy and precision of motion-sensing device (i.e. accelerometer) measurements. The main goals of this paper were to assess the accuracy and precision of these measurements against a gold standard, to determine if differences in manufacturing and assembly significantly affected device performance and to determine if measurement differences due to manufacturing and assembly could be corrected by applying certain post-processing techniques to the measurement data during analysis. In this paper, the validation of a posture and activity detector (PAD), a device containing a tri-axial accelerometer, is described. Validation of the PAD devices required the design of two test fixtures: a test fixture to position the device in a known orientation, and a test fixture to rotate the device at known velocities and accelerations. Device measurements were compared to these known orientations and accelerations. Several post-processing techniques were utilized in an attempt to reduce variability in the measurement error among the devices. In conclusion, some of the measurement errors due to the inevitable differences in manufacturing and assembly were significantly improved (p < 0.01) by these post-processing techniques.

  16. Performance Estimation of Silicon-Based Self-Cooling Device

    NASA Astrophysics Data System (ADS)

    Fukuda, Shinji; Sabi, Yuichi; Kawahara, Toshio; Yamaguchi, Satarou

    2013-05-01

    Since self-cooling devices were first proposed, several materials have been tested for their suitability to be used in them. A self-cooling device requires a high Seebeck coefficient, a low electrical resistivity, and a high thermal conductivity. Here, we report experimental results for single-crystal silicon doped with boron. Samples were fabricated with carrier densities in the range of 2.0×1015 to 1.6×1019 cm-3, and their Seebeck coefficient and electrical resistivity were measured. Silicon with a carrier density of 1.6×1019 cm-3 has a power factor of 4.8×10-3 W/(K2.m) at room temperature. The cooling capability of a self-cooling device was estimated using a one-dimensional model. The results suggest that a self-cooling device based on silicon with a high carrier density can have a higher heat removal performance than a conventional silicon power device of the same size.

  17. Mathematics Anxiety and the Affective Drop in Performance

    ERIC Educational Resources Information Center

    Ashcraft, Mark H.; Moore, Alex M.

    2009-01-01

    The authors provide a brief review of the history and assessment of math anxiety, its relationship to personal and educational consequences, and its important impact on measures of performance. Overall, math anxiety causes an "affective drop," a decline in performance when math is performed under timed, high-stakes conditions, both in laboratory…

  18. To BYOD or Not to BYOD: Factors Affecting Academic Acceptance of Student Mobile Devices in the Classroom

    ERIC Educational Resources Information Center

    Gillies, Christopher Graham Mckercher

    2016-01-01

    This article reports on factors affecting local academic acceptance of bring your own devices (BYOD). A review of the literature revealed a paucity of studies that have explored the complex factors that affect academic use and intention to use mobile devices in the classroom, with even less exploring truly ubiquitous and varied personal devices as…

  19. Performance and Challenges of Point of Use Devices for Lead ...

    EPA Pesticide Factsheets

    this presentation summarizes the performance of POU devices for the removal of lead and some other metals, in Flint, Michigan. The mechanism of POU filters for metal removal is described as being a combination of physical filtration with surface sorption and adherence to embedded functional groups in the carbon block, along with the certification process and how to find certified products from the web listings. Finally, there is a discussion of several alternative approaches for possible improvement of the NSF/ANSI 53 and 42 standards to improve the amount of protection afforded by the devices, in the future. this presentation summarizes the performance of POU devices for the removal of lead and some other metals, in Flint, Michigan. The mechanism of POU filters for metal removal is described as being a combination of physical filtration with surface sorption and adherence to embedded functional groups in the carbon block, along with the certification process and how to find certified products from the web listings. Finally, there is a discussion of several alternative approaches for possible improvement of the NSF/ANSI 53 and 42 standards to improve the amount of protection afforded by the devices, in the future.

  20. Interface engineering for high performance graphene electronic devices

    NASA Astrophysics Data System (ADS)

    Jung, Dae Yool; Yang, Sang Yoon; Park, Hamin; Shin, Woo Cheol; Oh, Joong Gun; Cho, Byung Jin; Choi, Sung-Yool

    2015-06-01

    A decade after the discovery of graphene flakes, exfoliated from graphite, we have now secured large scale and high quality graphene film growth technology via a chemical vapor deposition (CVD) method. With the establishment of mass production of graphene using CVD, practical applications of graphene to electronic devices have gained an enormous amount of attention. However, several issues arise from the interfaces of graphene systems, such as damage/unintentional doping of graphene by the transfer process, the substrate effects on graphene, and poor dielectric formation on graphene due to its inert features, which result in degradation of both electrical performance and reliability in actual devices. The present paper provides a comprehensive review of the recent approaches to resolve these issues by interface engineering of graphene for high performance electronic devices. We deal with each interface that is encountered during the fabrication steps of graphene devices, from the graphene/metal growth substrate to graphene/high-k dielectrics, including the intermediate graphene/target substrate.

  1. 40 CFR 63.997 - Performance test and compliance assessment requirements for control devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Devices, Recovery Devices and Routing to a Fuel Gas System or a Process § 63.997 Performance test and... permit, if an owner or operator elects to use a recovery device to replace an existing control device at a later date, or elects to use a different flare, nonflare control device or recovery device...

  2. 40 CFR 63.997 - Performance test and compliance assessment requirements for control devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Devices, Recovery Devices and Routing to a Fuel Gas System or a Process § 63.997 Performance test and... permit, if an owner or operator elects to use a recovery device to replace an existing control device at a later date, or elects to use a different flare, nonflare control device or recovery device...

  3. Perfectionism, Performance, and State Positive Affect and Negative Affect after a Classroom Test

    ERIC Educational Resources Information Center

    Flett, Gordon L.; Blankstein, Kirk R.; Hewitt, Paul L.

    2009-01-01

    The current study examined the associations among trait dimensions of perfectionism, test performance, and levels of positive and negative affect after taking a test. A sample of 92 female university students completed the Multidimensional Perfectionism Scale one week prior to an actual class test. Measures of positive affect and negative affect…

  4. Factors Affecting Performance of Undergraduate Students in Construction Related Disciplines

    ERIC Educational Resources Information Center

    Olatunji, Samuel Olusola; Aghimien, Douglas Omoregie; Oke, Ayodeji Emmanuel; Olushola, Emmanuel

    2016-01-01

    Academic performance of students in Nigerian institutions has been of much concern to all and sundry hence the need to assess the factors affecting performance of undergraduate students in construction related discipline in Nigeria. A survey design was employed with questionnaires administered on students in the department of Quantity Surveying,…

  5. Focus of Attention Affects Performance of Motor Skills in Music

    ERIC Educational Resources Information Center

    Duke, Robert A.; Cash, Carla Davis; Allen, Sarah E.

    2011-01-01

    To test the extent to which learners performing a simple keyboard passage would be affected by directing their focus of attention to different aspects of their movements, 16 music majors performed a brief keyboard passage under each of four focus conditions arranged in a counterbalanced design--a total of 64 experimental sessions. As they…

  6. Performance characterization of a rotary centrifugal left ventricular assist device with magnetic suspension.

    PubMed

    Jahanmir, Said; Hunsberger, Andrew Z; Heshmat, Hooshang; Tomaszewski, Michael J; Walton, James F; Weiss, William J; Lukic, Branka; Pae, William E; Zapanta, Conrad M; Khalapyan, Tigran Z

    2008-05-01

    The MiTiHeart (MiTiHeart Corporation, Gaithersburg, MD, USA) left ventricular assist device (LVAD), a third-generation blood pump, is being developed for destination therapy for adult heart failure patients of small to medium frame that are not being served by present pulsatile devices. The pump design is based on a novel, patented, hybrid passive/active magnetic bearing system with backup hydrodynamic thrust bearing and exhibits low power loss, low vibration, and low hemolysis. Performance of the titanium alloy prototype was evaluated in a series of in vitro tests with blood analogue to map out the performance envelop of the pump. The LVAD prototype was implanted in a calf animal model, and the in vivo pump performance was evaluated. The animal's native heart imparted a strong pulsatility to the flow rate. These tests confirmed the efficacy of the MiTiHeart LVAD design and confirmed that the pulsatility does not adversely affect the pump performance.

  7. Predicting performance expectations from affective impressions: linking affect control theory and status characteristics theory.

    PubMed

    Dippong, Joseph; Kalkhoff, Will

    2015-03-01

    Affect control theory (ACT) and status characteristics theory (SCT) offer separate and distinct explanations for how individuals interpret and process status- and power-relevant information about interaction partners. Existing research within affect control theory offers evidence that status and power are related to the affective impressions that individuals form of others along the dimensions of evaluation and potency, respectively. Alternately, status characteristics theory suggests that status and power influence interaction through the mediating cognitive construct of performance expectations. Although both theories have amassed an impressive amount of empirical support, research has yet to articulate theoretical and empirical connections between affective impressions and performance expectations. The purpose of our study is to address this gap. Elaborating a link between ACT and SCT in terms of their central concepts can serve as a stepping stone to improving the explanatory capacity of both theories, while providing a potential bridge by which they can be employed jointly.

  8. Performance pressure and caffeine both affect cognitive performance, but likely through independent mechanisms.

    PubMed

    Boere, Julia J; Fellinger, Lizz; Huizinga, Duncan J H; Wong, Sebastiaan F; Bijleveld, Erik

    2016-02-01

    A prevalent combination in daily life, performance pressure and caffeine intake have both been shown to impact people's cognitive performance. Here, we examined the possibility that pressure and caffeine affect cognitive performance via a shared pathway. In an experiment, participants performed a modular arithmetic task. Performance pressure and caffeine intake were orthogonally manipulated. Findings indicated that pressure and caffeine both negatively impacted performance. However, (a) pressure vs. caffeine affected performance on different trial types, and (b) there was no hint of an interactive effect. So, though the evidence is indirect, findings suggest that pressure and caffeine shape performance via distinct mechanisms, rather than a shared one.

  9. Novel nano materials for high performance logic and memory devices

    NASA Astrophysics Data System (ADS)

    Das, Saptarshi

    After decades of relentless progress, the silicon CMOS industry is approaching a stall in device performance for both logic and memory devices due to fundamental scaling limitations. In order to reinforce the accelerating pace, novel materials with unique properties are being proposed on an urgent basis. This list includes one dimensional nanotubes, quasi one dimensional nanowires, two dimensional atomistically thin layered materials like graphene, hexagonal boron nitride and the more recently the rich family of transition metal di-chalcogenides comprising of MoS2, WSe2, WS2 and many more for logic applications and organic and inorganic ferroelectrics, phase change materials and magnetic materials for memory applications. Only time will tell who will win, but exploring these novel materials allow us to revisit the fundamentals and strengthen our understanding which will ultimately be beneficial for high performance device design. While there has been growing interest in two-dimensional (2D) crystals other than graphene, evaluating their potential usefulness for electronic applications is still in its infancies due to the lack of a complete picture of their performance potential. The fact that the 2-D layered semiconducting di-chalcogenides need to be connected to the "outside" world in order to capitalize on their ultimate potential immediately emphasizes the importance of a thorough understanding of the contacts. This thesis demonstrate that through a proper understanding and design of source/drain contacts and the right choice of number of MoS2 layers the excellent intrinsic properties of this 2D material can be harvested. A comprehensive experimental study on the dependence of carrier mobility on the layer thickness of back gated multilayer MoS 2 field effect transistors is also provided. A resistor network model that comprises of Thomas-Fermi charge screening and interlayer coupling is used to explain the non-monotonic trend in the extracted field effect

  10. Principals' Perception regarding Factors Affecting the Performance of Teachers

    ERIC Educational Resources Information Center

    Akram, Muhammad Javaid; Raza, Syed Ahmad; Khaleeq, Abdur Rehman; Atika, Samrana

    2011-01-01

    This study investigated the perception of principals on how the factors of subject mastery, teaching methodology, personal characteristics, and attitude toward students affect the performance of teachers at higher secondary level in the Punjab. All principals of higher secondary level in the Punjab were part of the population of the study. From…

  11. Factors Affecting Performance in an Introductory Sociology Course

    ERIC Educational Resources Information Center

    Kwenda, Maxwell

    2011-01-01

    This study examines factors affecting students' performances in an Introductory Sociology course over five semesters. Employing simple and ordered logit regression models, the author explains final grades by focusing on individual demographic and educational characteristics that students bring into the classroom. The results show that a student's…

  12. Relations between affective music and speech: evidence from dynamics of affective piano performance and speech production

    PubMed Central

    Liu, Xiaoluan; Xu, Yi

    2015-01-01

    This study compares affective piano performance with speech production from the perspective of dynamics: unlike previous research, this study uses finger force and articulatory effort as indexes reflecting the dynamics of affective piano performance and speech production respectively. Moreover, for the first time physical constraints such as piano fingerings and speech articulatory constraints are included due to their potential contribution to different patterns of dynamics. A piano performance experiment and speech production experiment were conducted in four emotions: anger, fear, happiness and sadness. The results show that in both piano performance and speech production, anger and happiness generally have high dynamics while sadness has the lowest dynamics. Fingerings interact with fear in the piano experiment and articulatory constraints interact with anger in the speech experiment, i.e., large physical constraints produce significantly higher dynamics than small physical constraints in piano performance under the condition of fear and in speech production under the condition of anger. Using production experiments, this study firstly supports previous perception studies on relations between affective music and speech. Moreover, this is the first study to show quantitative evidence for the importance of considering motor aspects such as dynamics in comparing music performance and speech production in which motor mechanisms play a crucial role. PMID:26217252

  13. Relations between affective music and speech: evidence from dynamics of affective piano performance and speech production.

    PubMed

    Liu, Xiaoluan; Xu, Yi

    2015-01-01

    This study compares affective piano performance with speech production from the perspective of dynamics: unlike previous research, this study uses finger force and articulatory effort as indexes reflecting the dynamics of affective piano performance and speech production respectively. Moreover, for the first time physical constraints such as piano fingerings and speech articulatory constraints are included due to their potential contribution to different patterns of dynamics. A piano performance experiment and speech production experiment were conducted in four emotions: anger, fear, happiness and sadness. The results show that in both piano performance and speech production, anger and happiness generally have high dynamics while sadness has the lowest dynamics. Fingerings interact with fear in the piano experiment and articulatory constraints interact with anger in the speech experiment, i.e., large physical constraints produce significantly higher dynamics than small physical constraints in piano performance under the condition of fear and in speech production under the condition of anger. Using production experiments, this study firstly supports previous perception studies on relations between affective music and speech. Moreover, this is the first study to show quantitative evidence for the importance of considering motor aspects such as dynamics in comparing music performance and speech production in which motor mechanisms play a crucial role.

  14. Preparatory power posing affects nonverbal presence and job interview performance.

    PubMed

    Cuddy, Amy J C; Wilmuth, Caroline A; Yap, Andy J; Carney, Dana R

    2015-07-01

    The authors tested whether engaging in expansive (vs. contractive) "power poses" before a stressful job interview--preparatory power posing--would enhance performance during the interview. Participants adopted high-power (i.e., expansive, open) poses or low-power (i.e., contractive, closed) poses, and then prepared and delivered a speech to 2 evaluators as part of a mock job interview. All interview speeches were videotaped and coded for overall performance and hireability and for 2 potential mediators: verbal content (e.g., structure, content) and nonverbal presence (e.g., captivating, enthusiastic). As predicted, those who prepared for the job interview with high- (vs. low-) power poses performed better and were more likely to be chosen for hire; this relation was mediated by nonverbal presence, but not by verbal content. Although previous research has focused on how a nonverbal behavior that is enacted during interactions and observed by perceivers affects how those perceivers evaluate and respond to the actor, this experiment focused on how a nonverbal behavior that is enacted before the interaction and unobserved by perceivers affects the actor's performance, which, in turn, affects how perceivers evaluate and respond to the actor. This experiment reveals a theoretically novel and practically informative result that demonstrates the causal relation between preparatory nonverbal behavior and subsequent performance and outcomes.

  15. How motivation affects academic performance: a structural equation modelling analysis.

    PubMed

    Kusurkar, R A; Ten Cate, Th J; Vos, C M P; Westers, P; Croiset, G

    2013-03-01

    Few studies in medical education have studied effect of quality of motivation on performance. Self-Determination Theory based on quality of motivation differentiates between Autonomous Motivation (AM) that originates within an individual and Controlled Motivation (CM) that originates from external sources. To determine whether Relative Autonomous Motivation (RAM, a measure of the balance between AM and CM) affects academic performance through good study strategy and higher study effort and compare this model between subgroups: males and females; students selected via two different systems namely qualitative and weighted lottery selection. Data on motivation, study strategy and effort was collected from 383 medical students of VU University Medical Center Amsterdam and their academic performance results were obtained from the student administration. Structural Equation Modelling analysis technique was used to test a hypothesized model in which high RAM would positively affect Good Study Strategy (GSS) and study effort, which in turn would positively affect academic performance in the form of grade point averages. This model fit well with the data, Chi square = 1.095, df = 3, p = 0.778, RMSEA model fit = 0.000. This model also fitted well for all tested subgroups of students. Differences were found in the strength of relationships between the variables for the different subgroups as expected. In conclusion, RAM positively correlated with academic performance through deep strategy towards study and higher study effort. This model seems valid in medical education in subgroups such as males, females, students selected by qualitative and weighted lottery selection.

  16. Sleep complaints affecting school performance at different educational levels.

    PubMed

    Pagel, James F; Kwiatkowski, Carol F

    2010-01-01

    The clear association between reports of sleep disturbance and poor school performance has been documented for sleepy adolescents. This study extends that research to students outside the adolescent age grouping in an associated school setting (98 middle school students, 67 high school students, and 64 college students). Reported restless legs and periodic limb movements are significantly associated with lower GPA's in junior high students. Consistent with previous studies, daytime sleepiness was the sleep variable most likely to negatively affects high school students. Sleep onset and maintenance insomnia were the reported sleep variables significantly correlated with poorer school performance in college students. This study indicates that different sleep disorder variables negatively affect performance at different age and educational levels.

  17. Impact of hearing protection devices on sound localization performance

    PubMed Central

    Zimpfer, Véronique; Sarafian, David

    2014-01-01

    Hearing Protection Devices (HPDs) can protect the ear against loud potentially damaging sounds while allowing lower-level sounds such as speech to be perceived. However, the impact of these devices on the ability to localize sound sources is not well known. To address this question, we propose two different methods: one behavioral and one dealing with acoustical measurements. For the behavioral method, sound localization performance was measured with, and without, HPDs on 20 listeners. Five HPDs, including both passive (non-linear attenuation) and three active (talk-through) systems were evaluated. The results showed a significant increase in localization errors, especially front-back and up-down confusions relative to the “naked ear” test condition for all of the systems tested, especially for the talk-through headphone system. For the acoustic measurement method, Head-Related Transfer Functions (HRTFs) were measured on an artificial head both without, and with the HPDs in place. The effects of the HPDs on the spectral cues for the localization of different sound sources in the horizontal plane were analyzed. Alterations of the Interaural Spectral Difference (ISD) cues were identified, which could explain the observed increase in front-back confusions caused by the talk-through headphone protectors. PMID:24966807

  18. Effects of heavy ion radiation on digital micromirror device performance

    NASA Astrophysics Data System (ADS)

    Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan D.; Pellish, Jonny; Robberto, Massimo; Heap, Sara

    2016-09-01

    There is a pressing need in the astronomical community for space-suitable multiobject spectrometers (MOSs). Several digital micromirror device (DMD)-based prototype MOSs have been developed for ground-based observatories; however, their main use will come with deployment on a space-based mission. Therefore, the performance of DMDs under exoatmospheric radiation needs to be evaluated. DMDs were rewindowed with 2-μm thick pellicle and tested under accelerated heavy-ion radiation (control electronics shielded from radiation), with a focus on the detection of single-event effects (SEEs) including latch-up events. Testing showed that while DMDs are sensitive to nondestructive ion-induced state changes, all SEEs are cleared with a soft reset (i.e., sending a pattern to the device). The DMDs did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. This suggests that the SSE rate burden will be manageable for a DMD-based instrument when exposed to solar particle fluxes and cosmic rays in orbit.

  19. Chemical approaches to the improved performance of nanoelectronic devices

    NASA Astrophysics Data System (ADS)

    Chang, Noel N.

    Although randomly oriented CNT networks and polycrystalline graphene are easy to make and robust towards mechanical deformation, both materials suffer from resistive: at the intertube junctions in CNT networks and at grain boundaries in polycrystalline graphene sheets. In a process we have named "nanosoldering," a conductive material is deposited at the resistive junctions by operating the device in an atmosphere of a chemical precursor. The resistive heating that occurs at the "bad" junctions induces a thermal CVD process. The conductive material that is deposited at these junctions improves the overlap between the two nanotubes and decreases the junction resistance. Two precursors were utilized for this method: CpPd(allyl) to deposit Pd(0) and Hf(BH4)4 to deposit HfB2. In the SEM images post treatment, deposition is observed on many intertube junctions as well as along the lengths of some tubes; the latter can be eliminated by selecting the appropriate experimental conditions. For treatment with the Pd precursor, the ION/IOFF ratio improved by a factor of 6 on average. On the other hand, no improvement was observed for samples treated with the HfB2 precursor due to the large mismatch in work functions between CNTs and HfB2, which creates a Schottky barrier. A solution process was developed to improve the scalability of the nanosoldering process by eliminating the necessity of using a vacuum system and volatile chemical precursors. To do so, a nanosoldering precursor is spin-coated onto the solid substrate. The nanosoldering process is conducted in a commercial available probe station either in air or under vacuum, after which the excess material and byproduct are removed by a solvent rinse. Using this method, we show a comparable degree of device performance improvement using a nonvolatile Pd precursor, Pd2(dba)3. We also obtained improved device performance with a new carbon-based precursor, 1,3,5-tris(2-bromophenyl)benzene. Finally, preliminary experiments were

  20. Performance Testing using Silicon Devices - Analysis of Accuracy: Preprint

    SciTech Connect

    Sengupta, M.; Gotseff, P.; Myers, D.; Stoffel, T.

    2012-06-01

    Accurately determining PV module performance in the field requires accurate measurements of solar irradiance reaching the PV panel (i.e., Plane-of-Array - POA Irradiance) with known measurement uncertainty. Pyranometers are commonly based on thermopile or silicon photodiode detectors. Silicon detectors, including PV reference cells, are an attractive choice for reasons that include faster time response (10 us) than thermopile detectors (1 s to 5 s), lower cost and maintenance. The main drawback of silicon detectors is their limited spectral response. Therefore, to determine broadband POA solar irradiance, a pyranometer calibration factor that converts the narrowband response to broadband is required. Normally this calibration factor is a single number determined under clear-sky conditions with respect to a broadband reference radiometer. The pyranometer is then used for various scenarios including varying airmass, panel orientation and atmospheric conditions. This would not be an issue if all irradiance wavelengths that form the broadband spectrum responded uniformly to atmospheric constituents. Unfortunately, the scattering and absorption signature varies widely with wavelength and the calibration factor for the silicon photodiode pyranometer is not appropriate for other conditions. This paper reviews the issues that will arise from the use of silicon detectors for PV performance measurement in the field based on measurements from a group of pyranometers mounted on a 1-axis solar tracker. Also we will present a comparison of simultaneous spectral and broadband measurements from silicon and thermopile detectors and estimated measurement errors when using silicon devices for both array performance and resource assessment.

  1. Method and system for reducing device performance degradation of organic devices

    SciTech Connect

    Teague, Lucile C.

    2014-09-02

    Methods and systems for reducing the deleterious effects of gate bias stress on the drain current of an organic device, such as an organic thin film transistor, are provided. In a particular aspect, the organic layer of an organic device is illuminated with light having characteristics selected to reduce the gate bias voltage effects on the drain current of the organic device. For instance, the wavelength and intensity of the light are selected to provide a desired recovery of drain current of the organic device. If the characteristics of the light are appropriately matched to the organic device, recovery of the deleterious effects caused by gate bias voltage stress effects on the drain current of the organic device can be achieved. In a particular aspect, the organic device is selectively illuminated with light to operate the organic device in multiple modes of operation.

  2. The role of visual deprivation and experience on the performance of sensory substitution devices.

    PubMed

    Stronks, H Christiaan; Nau, Amy C; Ibbotson, Michael R; Barnes, Nick

    2015-10-22

    It is commonly accepted that the blind can partially compensate for their loss of vision by developing enhanced abilities with their remaining senses. This visual compensation may be related to the fact that blind people rely on their other senses in everyday life. Many studies have indeed shown that experience plays an important role in visual compensation. Numerous neuroimaging studies have shown that the visual cortices of the blind are recruited by other functional brain areas and can become responsive to tactile or auditory input instead. These cross-modal plastic changes are more pronounced in the early blind compared to late blind individuals. The functional consequences of cross-modal plasticity on visual compensation in the blind are debated, as are the influences of various etiologies of vision loss (i.e., blindness acquired early or late in life). Distinguishing between the influences of experience and visual deprivation on compensation is especially relevant for rehabilitation of the blind with sensory substitution devices. The BrainPort artificial vision device and The vOICe are assistive devices for the blind that redirect visual information to another intact sensory system. Establishing how experience and different etiologies of vision loss affect the performance of these devices may help to improve existing rehabilitation strategies, formulate effective selection criteria and develop prognostic measures. In this review we will discuss studies that investigated the influence of training and visual deprivation on the performance of various sensory substitution approaches.

  3. Factors Affecting Polymer Electrolyte Fuel Cells Performance and Reproducibility

    SciTech Connect

    Moller-Holst S.

    1998-11-01

    Development of fuel cells is often based on small-scale laboratory studies. Due to limited time and budgets, a minimum number of cells are usually prepared and tested, thus, conclusions about improved performance are often drawn from studies of a few cells. Generally, statistics showing the significance of an effect are seldom reported. In this work a simple PEM fuel cell electrode optimization experiment is used as an example to illustrate the importance of statistical evaluation of factors affecting cell performance. The use of fractional factorial design of experiments to reduce the number of cells that have to be studied is also addressed.

  4. 40 CFR 65.158 - Performance test procedures for control devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... performance test of a control device or a halogen reduction device, an owner or operator shall comply with the... halogen reduction device at maximum or minimum representative operating conditions for monitored control or halogen reduction device parameters, whichever results in lower emission reduction....

  5. 40 CFR 65.158 - Performance test procedures for control devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... performance test of a control device or a halogen reduction device, an owner or operator shall comply with the... halogen reduction device at maximum or minimum representative operating conditions for monitored control or halogen reduction device parameters, whichever results in lower emission reduction....

  6. Influence of material quality and process-induced defects on semiconductor device performance and yield

    NASA Technical Reports Server (NTRS)

    Porter, W. A.; Mckee, W. R.

    1974-01-01

    An overview of major causes of device yield degradation is presented. The relationships of device types to critical processes and typical defects are discussed, and the influence of the defect on device yield and performance is demonstrated. Various defect characterization techniques are described and applied. A correlation of device failure, defect type, and cause of defect is presented in tabular form with accompanying illustrations.

  7. High-Performance Permanent Magnets for Energy-Efficient Devices

    NASA Astrophysics Data System (ADS)

    Hadjipanayis, George

    2012-02-01

    Permanent magnets (PMs) are indispensable for many commercial applications including the electric, electronic and automobile industries, communications, information technologies and automatic control engineering. In most of these applications, an increase in the magnetic energy density of the PM, usually presented via the maximum energy product (BH)max, immediately increases the efficiency of the whole device and makes it smaller and lighter. Worldwide demand for high performance permanent magnets has increased dramatically in the past few years driven by hybrid and electric cars, wind turbines and other power generation systems. New energy challenges in the world require devices with higher energy efficiency and minimum environmental impact. The potential of 3d-4f compounds which revolutionized the PM science and technology is almost fully utilized, and the supply of 4f rare earth elements does not seem to be much longer assured. This talk will address the major principles guiding the development of PMs and overview state-of-the-art theoretical and experimental research. Recent progress in the development of nanocomposite PMs, consisting of a fine (at the scale of the magnetic exchange length) mixture of phases with high magnetization and large magnetic hardness will be discussed. Fabrication of such PMs is currently the most promising way to boost the (BH)max, while simultaneously decreasing, at least partially, the reliance on the rare earth elements. Special attention will be paid to the impact which the next-generation high-(BH)max magnets is expected to have on existing and proposed energy-saving technologies.

  8. Crystal structure engineering for improved performance of emerging nanoscale devices

    NASA Astrophysics Data System (ADS)

    Chimalgi, Vinay Uday

    Recent advances in growth techniques and increasing number of experimental studies have made nanostructures grown along different crystallographic directions a reality. These new structures could not only benefit the electronic devices used in mainstream information technology but also show great promise for applications in lasers, solid-state lighting, near-field photolithography, free-space quantum cryptography, consumer displays, quantum computation, as well as diagnostic medicine and imaging. However, only few theoretical investigations have been performed on these structures due to the complex nature of the interplay of atomicity, structural fields, polarization, and quantum size-quantization, all strong function of the crystallographic direction. The objective of this work is mainly four-fold: (1) Integrate a computational framework employing a combination of fully atomistic valence force-field molecular mechanics and 20-band sp3s*d5-SO tight-binding based electronic band­structure models, and numerically investigate the effects of internal fields on the electronic and optical properties of zincblende InAs/GaAs quantum dots grown on (100), (110), and (111) orientated substrates. (2) Augment/extend the open source NEMO 3-D bandstructure simulator by incorporating a recently proposed first principles based model to gauge the importance of nonlinear piezoelectricity on the single-particle electronic states and interband optical transitions in emerging In(Ga)N/GaN disk-in-wire LED structures having c-plane and m-plane wurtzite crystal symmetry. (3) Coupling the NEMO 3-D software toolkit with a commercial TCAD simulator to determine the terminal electrical and optical characteristics of InGaN/GaN disk-in-wire LEDs; and (4) Finding an optimum crystallographic device for InGaN/GaN disk-in-wire LEDs to achieve improved internal quantum efficiency (IQE).

  9. Binaural auditory beats affect vigilance performance and mood.

    PubMed

    Lane, J D; Kasian, S J; Owens, J E; Marsh, G R

    1998-01-01

    When two tones of slightly different frequency are presented separately to the left and right ears the listener perceives a single tone that varies in amplitude at a frequency equal to the frequency difference between the two tones, a perceptual phenomenon known as the binaural auditory beat. Anecdotal reports suggest that binaural auditory beats within the electroencephalograph frequency range can entrain EEG activity and may affect states of consciousness, although few scientific studies have been published. This study compared the effects of binaural auditory beats in the EEG beta and EEG theta/delta frequency ranges on mood and on performance of a vigilance task to investigate their effects on subjective and objective measures of arousal. Participants (n = 29) performed a 30-min visual vigilance task on three different days while listening to pink noise containing simple tones or binaural beats either in the beta range (16 and 24 Hz) or the theta/delta range (1.5 and 4 Hz). However, participants were kept blind to the presence of binaural beats to control expectation effects. Presentation of beta-frequency binaural beats yielded more correct target detections and fewer false alarms than presentation of theta/delta frequency binaural beats. In addition, the beta-frequency beats were associated with less negative mood. Results suggest that the presentation of binaural auditory beats can affect psychomotor performance and mood. This technology may have applications for the control of attention and arousal and the enhancement of human performance.

  10. Analysis of factors affecting milking claw vacuum levels using a simulated milking device.

    PubMed

    Enokidani, Masafumi; Kuruhara, Kana; Kawai, Kazuhiro

    2016-06-01

    Bovine mastitis is typically caused by microbial infection of the udder, but the factors responsible for this condition are varied. One potential cause is the milking system, and although previous studies have investigated various methods for inspecting these devices, most have not assessed methods for evaluating the milking units. With this in mind, we analyzed the factors that affect the vacuum inside the milking claw by using a simulated milking device and by measuring milking claw vacuum when adjusting the flow rate in five stages. The factors analyzed in each milking system were the vacuum pressure settings (high and low line system) , milk tube length (200-328 cm), aperture diameter (14-22.2 mm), constricted aperture diameter (12 mm), tubing configurations, lift formation (0-80 cm), claw type (bottom and top flow) and use or non-use of a milk sampler. The study findings demonstrated that all of these variables had a significant impact on claw vacuum and suggest that a diagnostic method using a simulated milking device should be considered when inspecting modern milking systems.

  11. Does Question Structure Affect Exam Performance in the Geosciences?

    NASA Astrophysics Data System (ADS)

    Day, E. A.; D'Arcy, M. K.; Craig, L.; Streule, M. J.; Passmore, E.; Irving, J. C. E.

    2015-12-01

    The jump to university level exams can be challenging for some students, often resulting in poor marks, which may be detrimental to their confidence and ultimately affect their overall degree class. Previous studies have found that question structure can have a strong impact on the performance of students in college level exams (see Gibson et al., 2015, for a discussion of its impact on physics undergraduates). Here, we investigate the effect of question structure on the exam results of geology and geophysics undergraduate students. Specifically, we analyse the performance of students in questions that have a 'scaffolded' framework and compare them to their performance in open-ended questions and coursework. We also investigate if observed differences in exam performance are correlated with the educational background and gender of students, amongst other factors. It is important for all students to be able to access their degree courses, no matter what their backgrounds may be. Broadening participation in the geosciences relies on removing systematic barriers to achievement. Therefore we recommend that exams are either structured with scaffolding in questions at lower levels, or students are explicitly prepared for this transition. We also recommend that longitudinal studies of exam performance are conducted within individual departments, and this work outlines one approach to analysing performance data.

  12. Method and devices for performing stereotactic microbeam radiation therapy

    DOEpatents

    Dilmanian, F. Avraham

    2010-01-05

    A radiation delivery system generally includes either a synchrotron source or a support frame and a plurality of microbeam delivery devices supported on the support frame, both to deliver a beam in a hemispherical arrangement. Each of the microbeam delivery devices or synchrotron irradiation ports is adapted to deliver at least one microbeam of radiation along a microbeam delivery axis, wherein the microbeam delivery axes of the plurality of microbeam delivery devices cross within a common target volume.

  13. II-VI Materials-Based High Performance Intersubband Devices

    NASA Astrophysics Data System (ADS)

    Ravikumar, Arvind Pawan

    achieve normal-incident absorption, taking advantage of light-scattering in sloped surfaces; this method is wavelength independent and does not involve complicated fabrication techniques. With the performance of II-VI devices matching or surpassing existing commercial solutions, integrated mid-IR photonics based sensing is poised to play a big role in the future of sensing technologies.

  14. 40 CFR 1700.14 - Marine Pollution Control Device (MPCD) Performance Standards. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Marine Pollution Control Device (MPCD... DISCHARGE STANDARDS FOR VESSELS OF THE ARMED FORCES Marine Pollution Control Device (MPCD) Performance Standards § 1700.14 Marine Pollution Control Device (MPCD) Performance Standards....

  15. 40 CFR 1700.14 - Marine Pollution Control Device (MPCD) Performance Standards. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Marine Pollution Control Device (MPCD... DISCHARGE STANDARDS FOR VESSELS OF THE ARMED FORCES Marine Pollution Control Device (MPCD) Performance Standards § 1700.14 Marine Pollution Control Device (MPCD) Performance Standards....

  16. 40 CFR 1700.14 - Marine Pollution Control Device (MPCD) Performance Standards. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Marine Pollution Control Device (MPCD... UNIFORM NATIONAL DISCHARGE STANDARDS FOR VESSELS OF THE ARMED FORCES Marine Pollution Control Device (MPCD) Performance Standards § 1700.14 Marine Pollution Control Device (MPCD) Performance Standards. [Reserved]...

  17. 40 CFR 1700.14 - Marine Pollution Control Device (MPCD) Performance Standards. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Marine Pollution Control Device (MPCD... DISCHARGE STANDARDS FOR VESSELS OF THE ARMED FORCES Marine Pollution Control Device (MPCD) Performance Standards § 1700.14 Marine Pollution Control Device (MPCD) Performance Standards....

  18. 40 CFR 1700.14 - Marine Pollution Control Device (MPCD) Performance Standards. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Marine Pollution Control Device (MPCD... DISCHARGE STANDARDS FOR VESSELS OF THE ARMED FORCES Marine Pollution Control Device (MPCD) Performance Standards § 1700.14 Marine Pollution Control Device (MPCD) Performance Standards....

  19. Error framing effects on performance: cognitive, motivational, and affective pathways.

    PubMed

    Steele-Johnson, Debra; Kalinoski, Zachary T

    2014-01-01

    Our purpose was to examine whether positive error framing, that is, making errors salient and cuing individuals to see errors as useful, can benefit learning when task exploration is constrained. Recent research has demonstrated the benefits of a newer approach to training, that is, error management training, that includes the opportunity to actively explore the task and framing errors as beneficial to learning complex tasks (Keith & Frese, 2008). Other research has highlighted the important role of errors in on-the-job learning in complex domains (Hutchins, 1995). Participants (N = 168) from a large undergraduate university performed a class scheduling task. Results provided support for a hypothesized path model in which error framing influenced cognitive, motivational, and affective factors which in turn differentially affected performance quantity and quality. Within this model, error framing had significant direct effects on metacognition and self-efficacy. Our results suggest that positive error framing can have beneficial effects even when tasks cannot be structured to support extensive exploration. Whereas future research can expand our understanding of error framing effects on outcomes, results from the current study suggest that positive error framing can facilitate learning from errors in real-time performance of tasks.

  20. Axial flow ventricular assist device: system performance considerations.

    PubMed

    Damm, G; Mizuguchi, K; Aber, G; Bacak, J; Akkerman, J; Bozeman, R; Svejkovsky, P; Takatani, S; Nosé, Y; Noon, G P

    1994-01-01

    A cooperative effort between Baylor College of Medicine and NASA/Johnson Space Center is under way to develop an implantable left ventricular assist device for either pulmonary or systemic circulatory support for more than 3 months' duration. Using methodical evaluation and testing, an implantable axial pump has been systematically improved. These improvements include the addition of an inducer as a pumping element in front of the impeller and the construction of an efficient brushless direct current motor. To date, less than 10 W of power is required to generate 5 L/min flow against 100 mm Hg. An index of hemolysis of 0.021 g/100 L has been achieved. Two-day in vivo feasibility studies in calves are under way to evaluate the antithrombogenic nature of the pump. Further improvements in system efficiency, hemolytic performance, and the antithrombogenic nature of the pump are expected with the use of empirical studies, computer flow modeling, and in vivo testing in calves.

  1. Field Performance of a Newly Developed Upflow Filtration Device

    EPA Science Inventory

    The objective of this research is to examine the removal capacities of a newly developed Upflow filtration device for treatment of stormwater. The device was developed by engineers at the University of Alabama through a Small Business Innovative Research (SBIR) grant from the U....

  2. Tail regeneration affects the digestive performance of a Mediterranean lizard

    NASA Astrophysics Data System (ADS)

    Sagonas, Kostas; Karambotsi, Niki; Bletsa, Aristoula; Reppa, Aikaterini; Pafilis, Panayiotis; Valakos, Efstratios D.

    2017-04-01

    In caudal autotomy, lizards shed their tail to escape from an attacking predator. Since the tail serves multiple functions, caudal regeneration is of pivotal importance. However, it is a demanding procedure that requires substantial energy and nutrients. Therefore, lizards have to increase energy income to fuel the extraordinary requirements of the regenerating tail. We presumed that autotomized lizards would adjust their digestion to acquire this additional energy. To clarify the effects of tail regeneration on digestion, we compared the digestive performance before autotomy, during regeneration, and after its completion. Tail regeneration indeed increased gut passage time but did not affect digestive performance in a uniform pattern: though protein income was maximized, lipid and sugar acquisition remained stable. This divergence in proteins may be attributed to their particular role in tail reconstruction, as they are the main building blocks for tissue formation.

  3. Can small shifts in circadian phase affect performance?

    PubMed Central

    Burgess, Helen J.; Legasto, Carlo S.; Fogg, Louis F.; Smith, Mark R.

    2012-01-01

    Small shifts in circadian timing occur frequently as a result of daylight saving time or later weekend sleep. These subtle shifts in circadian phase have been shown to influence subjective sleepiness, but it remains unclear if they can significantly affect performance. In a retrospective analysis we examined performance on the Psychomotor Vigilance Test before bedtime and after wake time in 11 healthy adults on fixed sleep schedules based on their habitual sleep times. The dim light melatonin onset, a marker of circadian timing, was measured on two occasions. An average 1.1 hour shift away from a proposed optimal circadian phase angle (6 hours between melatonin onset and midpoint of sleep) significantly slowed mean, median and fastest 10% reaction times before bedtime and after wake time (p<0.05). These results add to previous reports that suggest that humans may be sensitive to commonly occurring small shifts in circadian timing. PMID:22695081

  4. Can small shifts in circadian phase affect performance?

    PubMed

    Burgess, Helen J; Legasto, Carlo S; Fogg, Louis F; Smith, Mark R

    2013-01-01

    Small shifts in circadian timing occur frequently as a result of daylight saving time or later weekend sleep. These subtle shifts in circadian phase have been shown to influence subjective sleepiness, but it remains unclear if they can significantly affect performance. In a retrospective analysis we examined performance on the Psychomotor Vigilance Test before bedtime and after wake time in 11 healthy adults on fixed sleep schedules based on their habitual sleep times. The dim light melatonin onset, a marker of circadian timing, was measured on two occasions. An average 1.1 h shift away from a proposed optimal circadian phase angle (6 h between melatonin onset and midpoint of sleep) significantly slowed mean, median and fastest 10% reaction times before bedtime and after wake time (p < 0.05). These results add to previous reports that suggest that humans may be sensitive to commonly occurring small shifts in circadian timing.

  5. Performance of device-independent quantum key distribution

    NASA Astrophysics Data System (ADS)

    Cao, Zhu; Zhao, Qi; Ma, Xiongfeng

    2016-07-01

    Quantum key distribution provides information-theoretically-secure communication. In practice, device imperfections may jeopardise the system security. Device-independent quantum key distribution solves this problem by providing secure keys even when the quantum devices are untrusted and uncharacterized. Following a recent security proof of the device-independent quantum key distribution, we improve the key rate by tightening the parameter choice in the security proof. In practice where the system is lossy, we further improve the key rate by taking into account the loss position information. From our numerical simulation, our method can outperform existing results. Meanwhile, we outline clear experimental requirements for implementing device-independent quantum key distribution. The maximal tolerable error rate is 1.6%, the minimal required transmittance is 97.3%, and the minimal required visibility is 96.8 % .

  6. Outdoor performance testing of thin-film devices

    NASA Astrophysics Data System (ADS)

    1985-10-01

    The Advanced Systems Research Group supports the photovoltaic advanced R&D (PV AR&D) project by providing outdoor (global) testing of PV cells, submodules, modules, and arrays. The group also provides in house engineering and analysis to identify and determine how technical issues such as cell/module/system adaptations, long term stability, reliability, economics, materials availability, safety, and environmental impacts affect the development and ultimate use of advanced PV thin film, innovative cell, and material technologies. A major thrust of the research effort is to develop and utilize instrumentation and procedures for monitoring and analyzing PV cells and submodules including outdoor performance and stability testing and life cycle accelerated stress testing. To accomplish the above, the solar energy research institute (SERI) outdoor PV test facility was established in 1982. The group has designed testing systems and analysis procedures for, and has tested, numerous amorphous silicon thin film submodules provided by SERI subcontractors and has performed long term outdoor stability tests on CdS/CuIr Se sub 2 and hydrogen passivated silicon solar cells. A significant contribution from this facility over the past year was the testing of large area amorphous silicon submodules.

  7. Lagrangian methods for blood damage estimation in cardiovascular devices--How numerical implementation affects the results.

    PubMed

    Marom, Gil; Bluestein, Danny

    2016-01-01

    This paper evaluated the influence of various numerical implementation assumptions on predicting blood damage in cardiovascular devices using Lagrangian methods with Eulerian computational fluid dynamics. The implementation assumptions that were tested included various seeding patterns, stochastic walk model, and simplified trajectory calculations with pathlines. Post processing implementation options that were evaluated included single passage and repeated passages stress accumulation and time averaging. This study demonstrated that the implementation assumptions can significantly affect the resulting stress accumulation, i.e., the blood damage model predictions. Careful considerations should be taken in the use of Lagrangian models. Ultimately, the appropriate assumptions should be considered based the physics of the specific case and sensitivity analysis, similar to the ones presented here, should be employed.

  8. Lagrangian methods for blood damage estimation in cardiovascular devices - How numerical implementation affects the results

    PubMed Central

    Marom, Gil; Bluestein, Danny

    2016-01-01

    Summary This paper evaluated the influence of various numerical implementation assumptions on predicting blood damage in cardiovascular devices using Lagrangian methods with Eulerian computational fluid dynamics. The implementation assumptions that were tested included various seeding patterns, stochastic walk model, and simplified trajectory calculations with pathlines. Post processing implementation options that were evaluated included single passage and repeated passages stress accumulation and time averaging. This study demonstrated that the implementation assumptions can significantly affect the resulting stress accumulation, i.e., the blood damage model predictions. Careful considerations should be taken in the use of Lagrangian models. Ultimately, the appropriate assumptions should be considered based the physics of the specific case and sensitivity analysis, similar to the ones presented here, should be employed. PMID:26679833

  9. Effect of relative humidity on crystal growth, device performance and hysteresis in planar heterojunction perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Gangishetty, Mahesh K.; Scott, Robert W. J.; Kelly, Timothy L.

    2016-03-01

    Due to the hygroscopic nature of organolead halide perovskites, humidity is one of the most important factors affecting the efficiency and longevity of perovskite solar cells. Although humidity has a long term detrimental effect on device performance, it also plays a key role during the initial growth of perovskite crystals. Here we demonstrate that atmospheric relative humidity (RH) plays a key role during the formation of perovskite thin films via the sequential deposition technique. Our results indicate that the RH has a substantial impact on the crystallization process, and hence on device performance. SEM and pXRD analysis show an increase in crystallite size with increasing humidity. At low RH, the formation of small cubic crystallites with large gaps between them is observed. The presence of these voids adversely affects device performance and leads to substantial hysteresis in the device. At higher RH, the perovskite crystals are larger in size, with better connectivity between the crystallites. This produced efficient planar heterojunction solar cells with low hysteresis. By careful control of the RH during the cell fabrication process, efficiencies of up to 12.2% are reached using P3HT as the hole-transport material.Due to the hygroscopic nature of organolead halide perovskites, humidity is one of the most important factors affecting the efficiency and longevity of perovskite solar cells. Although humidity has a long term detrimental effect on device performance, it also plays a key role during the initial growth of perovskite crystals. Here we demonstrate that atmospheric relative humidity (RH) plays a key role during the formation of perovskite thin films via the sequential deposition technique. Our results indicate that the RH has a substantial impact on the crystallization process, and hence on device performance. SEM and pXRD analysis show an increase in crystallite size with increasing humidity. At low RH, the formation of small cubic crystallites

  10. Fabrication and performance of contamination free individual single-walled carbon nanotube optical devices.

    PubMed

    Zhou, Yuxiu; Cheng, Rong; Liu, Jianqiang; Li, Tie

    2014-06-01

    Contamination free individual single-walled carbon nanotube (SWCNT) optical devices are fabricated using a hybrid method in the purpose of increase sensitivity as well as further understanding the sensing mechanism. The devices were tested in vacuum to avoid contamination. Three typical devices are discussed comparatively. Under infrared lamp illumination, photovoltaic and photoconductive properties are revealed in device A and B respectively, while device C shows no detectable signal. The photoresponse of device B reaches 108% at 78 K, much larger than that of horizontally aligned or network carbon nanotube devices, indicating priority of the individual nanotube device structure. Interestingly, the temperature characteristics of device A and B are just the opposite. The individual SWCNT devices hold promise in high performance and low cost optical sensors as well as nano-scale solar cells.

  11. Silicon Carbide Power Device Performance Under Heavy-Ion Irradiation

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie; Casey, Megan; Topper, Alyson; Wilcox, Edward; Phan, Anthony; Ikpe, Stanley; LaBel, Ken

    2015-01-01

    Heavy-ion induced degradation and catastrophic failure data for SiC power MOSFETs and Schottky diodes are examined to provide insight into the challenge of single-event effect hardening of SiC power devices.

  12. Interface Design Principles for High-Performance Organic Semiconductor Devices.

    PubMed

    Nie, Wanyi; Gupta, Gautam; Crone, Brian K; Liu, Feilong; Smith, Darryl L; Ruden, P Paul; Kuo, Cheng-Yu; Tsai, Hsinhan; Wang, Hsing-Lin; Li, Hao; Tretiak, Sergei; Mohite, Aditya D

    2015-06-01

    Precise manipulation of organic donor-acceptor interfaces using spacer layers is demonstrated to suppress interface recombination in an organic photo-voltaic device. These strategies lead to a dramatic improvement in a model bilayer system and bulk-heterojunction system. These interface strategies are applicable to a wide variety of donor-acceptor systems, making them both fundamentally interesting and technologically relevant for achieving high efficiency organic electronic devices.

  13. Human Performance Data Needed for Training Device Design Decisions.

    DTIC Science & Technology

    1987-03-01

    know more about night vision and the effect of Training Device (TD) layout on visual perception. Next to vision , the most frequently Queried domain in...general 14 alphanumeric 5 symbols 18 dynamics 10 organization 6 anomalous effects 14 color 5 Night Vision 6 Vision and TD Layout 12 Visual vs. Vestibular...device designers, helping them to find the topic of greatest relevance (e.g., CRT alphanumerics, night vision , motion cues). Such a supplement might

  14. Silicon device performance measurements to support temperature range enhancement

    NASA Technical Reports Server (NTRS)

    Bromstead, James; Weir, Bennett; Cosby, Melvin; Johnson, R. Wayne; Nelms, R. Mark; Askew, Ray

    1992-01-01

    Characterization results of a MOS controlled thyristor (MCTA60P60) are presented. This device is rated for 60A and for an anode to cathode voltage of -600 V. As discussed in the last report, the MCT failed during 500 V leakage tests at 200 C. In contrast to the BJT (bipolar junction transistor), MOSFET, and IGBT (insulated gate bipolar transistor) devices tested, the breakdown voltage of the MCT decreases significantly with increasing temperature.

  15. Hemodynamic Performance of a Novel Right Ventricular Assist Device (PERKAT)

    PubMed Central

    Schulze, P. Christian; Ferrari, Markus W.

    2017-01-01

    Acute right ventricular failure (RVF) is an increasing clinical problem and a life-threatening condition. Right ventricular assist devices represent a reasonable treatment option for patients with refractory RVF. We here present a novel percutaneously implantable device for right ventricular support. The PERKAT device is based on a nitinol stent cage, which is covered with valve-carrying foils. A flexible outlet trunk with a pigtail tip is connected to the distal part. The device is driven by an intra-aortic balloon pump (IABP) drive unit, which inflates/deflates a standard IABP-balloon placed within the stent cage. In-vitro evaluation was done in a liquid bath containing water or blood analog. The PERKAT device was tested in different afterload settings using two different IABP-balloons and varying inflation/deflation rates. We detected flow rates ranging from 1.97 to 3.93 L/min depending on the afterload setting, inflation/deflation rate, balloon size, and the medium used. Flow rates between water and blood analog were nearly comparable, and in the higher inflation/deflation rate settings slightly higher with water. Based on this promising in vitro data, the innovative percutaneously implantable PERKAT device has a potential to become a therapeutic option for patients with RVF refractory to medical treatment. PMID:27831998

  16. The science of cycling: factors affecting performance - part 2.

    PubMed

    Faria, Erik W; Parker, Daryl L; Faria, Irvin E

    2005-01-01

    This review presents information that is useful to athletes, coaches and exercise scientists in the adoption of exercise protocols, prescription of training regimens and creation of research designs. Part 2 focuses on the factors that affect cycling performance. Among those factors, aerodynamic resistance is the major resistance force the racing cyclist must overcome. This challenge can be dealt with through equipment technological modifications and body position configuration adjustments. To successfully achieve efficient transfer of power from the body to the drive train of the bicycle the major concern is bicycle configuration and cycling body position. Peak power output appears to be highly correlated with cycling success. Likewise, gear ratio and pedalling cadence directly influence cycling economy/efficiency. Knowledge of muscle recruitment throughout the crank cycle has important implications for training and body position adjustments while climbing. A review of pacing models suggests that while there appears to be some evidence in favour of one technique over another, there remains the need for further field research to validate the findings. Nevertheless, performance modelling has important implications for the establishment of performance standards and consequent recommendations for training.

  17. Lithium-oxygen batteries-Limiting factors that affect performance

    NASA Astrophysics Data System (ADS)

    Padbury, Richard; Zhang, Xiangwu

    2011-05-01

    Lithium-oxygen batteries have recently received attention due to their extremely high theoretical energy densities, which far exceed that of any other existing energy storage technology. The significantly larger theoretical energy density of the lithium-oxygen batteries is due to the use of a pure lithium metal anode and the fact that the cathode oxidant, oxygen, is stored externally since it can be readily obtained from the surrounding air. Before the lithium-oxygen batteries can be realized as high performance, commercially viable products, there are still many challenges to overcome, from designing their cathode structure, to optimizing their electrolyte compositions and elucidating the complex chemical reactions that occur during charge and discharge. The scientific obstacles that are related to the performance of the lithium-oxygen batteries open up an exciting opportunity for researchers from many different backgrounds to utilize their unique knowledge and skills to bridge the knowledge gaps that exist in current research projects. This article is a summary of the most significant limiting factors that affect the performance of the lithium-oxygen batteries from the perspective of the authors. The article indicates the relationships that form between various limiting factors and highlights the complex yet captivating nature of the research within this field.

  18. Parents' job insecurity affects children's academic performance through cognitive difficulties.

    PubMed

    Barling, J; Zacharatos, A; Hepburn, C G

    1999-06-01

    The authors developed and tested a model in which children who perceive their parents to be insecure about their jobs are distracted cognitively, which in turn affects their academic performance negatively. Participants were 102 female and 18 male undergraduates (mean age = 18 years), their fathers (mean age = 49 years), and their mothers (mean age = 47 years). Students completed questionnaires measuring perceived parental job insecurity, identification with parents, and cognitive difficulties; 3 months later, they also reported their midyear grades. Fathers and mothers each completed questionnaires assessing their job insecurity. Support for the model was obtained using LISREL 8, and as predicted, children's identification with their mothers and fathers moderated the relationship between their perceptions of their mothers' and fathers' job insecurity and their own cognitive difficulties.

  19. Tuning the Performance of Organic Spintronic Devices Using X-Ray Generated Traps

    DTIC Science & Technology

    2012-08-16

    REPORT Tuning the Performance of Organic Spintronic Devices Using X-Ray Generated Traps 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: X rays produced...during electron-beam deposition of metallic electrodes drastically change the performance of organic spintronic devices. The x rays generate traps with...Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - Tuning the Performance of Organic Spintronic Devices Using X-Ray Generated Traps Report Title

  20. Irrelevant events affect voters' evaluations of government performance

    PubMed Central

    Healy, Andrew J.; Malhotra, Neil; Mo, Cecilia Hyunjung

    2010-01-01

    Does information irrelevant to government performance affect voting behavior? If so, how does this help us understand the mechanisms underlying voters’ retrospective assessments of candidates’ performance in office? To precisely test for the effects of irrelevant information, we explore the electoral impact of local college football games just before an election, irrelevant events that government has nothing to do with and for which no government response would be expected. We find that a win in the 10 d before Election Day causes the incumbent to receive an additional 1.61 percentage points of the vote in Senate, gubernatorial, and presidential elections, with the effect being larger for teams with stronger fan support. In addition to conducting placebo tests based on postelection games, we demonstrate these effects by using the betting market's estimate of a team's probability of winning the game before it occurs to isolate the surprise component of game outcomes. We corroborate these aggregate-level results with a survey that we conducted during the 2009 NCAA men's college basketball tournament, where we find that surprising wins and losses affect presidential approval. An experiment embedded within the survey also indicates that personal well-being may influence voting decisions on a subconscious level. We find that making people more aware of the reasons for their current state of mind reduces the effect that irrelevant events have on their opinions. These findings underscore the subtle power of irrelevant events in shaping important real-world decisions and suggest ways in which decision making can be improved. PMID:20615955

  1. Irrelevant events affect voters' evaluations of government performance.

    PubMed

    Healy, Andrew J; Malhotra, Neil; Mo, Cecilia Hyunjung

    2010-07-20

    Does information irrelevant to government performance affect voting behavior? If so, how does this help us understand the mechanisms underlying voters' retrospective assessments of candidates' performance in office? To precisely test for the effects of irrelevant information, we explore the electoral impact of local college football games just before an election, irrelevant events that government has nothing to do with and for which no government response would be expected. We find that a win in the 10 d before Election Day causes the incumbent to receive an additional 1.61 percentage points of the vote in Senate, gubernatorial, and presidential elections, with the effect being larger for teams with stronger fan support. In addition to conducting placebo tests based on postelection games, we demonstrate these effects by using the betting market's estimate of a team's probability of winning the game before it occurs to isolate the surprise component of game outcomes. We corroborate these aggregate-level results with a survey that we conducted during the 2009 NCAA men's college basketball tournament, where we find that surprising wins and losses affect presidential approval. An experiment embedded within the survey also indicates that personal well-being may influence voting decisions on a subconscious level. We find that making people more aware of the reasons for their current state of mind reduces the effect that irrelevant events have on their opinions. These findings underscore the subtle power of irrelevant events in shaping important real-world decisions and suggest ways in which decision making can be improved.

  2. Evaluation of the performance of orthodontic devices using FBG sensors

    NASA Astrophysics Data System (ADS)

    Carvalho, L.; Roriz, P.; Frazão, O.; Marques, M. B.

    2015-04-01

    Cross-bite, as a malocclusion effect, is defined as a transversal changing of the upper dental arch, in relation to the lower arch, and may be classified as skeletal, dental or functional. As a consequence, the expansion of maxilla is an effective clinical treatment used to correct transversal maxillary discrepancy. The maxillary expansion is an ancient method used in orthodontics, for the correction of the maxillary athresia with posterior crossbite, through the opening of the midpalatal suture (disjunction), using orthodontic- orthopaedic devices. Same controversial discussion arises among the clinicians, about the effects of each orthodontic devices as also about the technique to be employed. The objective of this study was to compare the strain field induced by two different orthodontic devices, named disjunctor with and without a connecting bar, in an acrylic model jaw, using fiber Bragg grating sensors to measure the strain patterns. The orthodontic device disjunctor with the bar, in general, transmits higher forces and strain to teeth and maxillae, than with the disjunctor without bar. It was verified that the strain patterns were not symmetric between the left and the right sides as also between the posterior and anterior regions of the maxillae. For the two devices is also found that in addition a displacement in the horizontal plane, particularly in posterior teeth, also occurs a rotation corresponding to a vestibularization of the posterior teeth and their alveolar processes.

  3. Silicon device performance measurements to support temperature range enhancement

    NASA Technical Reports Server (NTRS)

    Bromstead, James; Weir, Bennett; Johnson, R. Wayne; Askew, Ray

    1991-01-01

    Semiconductor power devices are typically rated for operation below 150 C. Little data is known for power semiconductors over 150 C. In most cases, the device is derated to zero operating power at 175 C. At the high temperature end of the temperature range, the intrinsic carrier concentration increases to equal the doping concentration level and the silicon behaves as an intrinsic semiconductor. The increase in intrinsic carrier concentration results in a shift of the Fermi level toward mid-bandgap at elevated temperatures. This produces a shift in devices characteristics as a function of temperature. By increasing the doping concentration higher operating temperatures can be achieved. This technique was used to fabricate low power analog and digital devices in silicon with junction operating temperatures in excess of 300 C. Additional temperature effects include increased p-n junction leakage with increasing temperature, resulting in increased resistivity. The temperature dependency of physical properties results in variations in device characteristics. These must be quantified and understood in order to develop extended temperature range operation.

  4. Silicon device performance measurements to support temperature range enhancement

    NASA Technical Reports Server (NTRS)

    Bromstead, James; Weir, Bennett; Nelms, R. Mark; Johnson, R. Wayne; Askew, Ray

    1994-01-01

    Silicon based power devices can be used at 200 C. The device measurements made during this program show a predictable shift in device parameters with increasing temperature. No catastrophic or abrupt changes occurred in the parameters over the temperature range. As expected, the most dramatic change was the increase in leakage currents with increasing temperature. At 200 C the leakage current was in the milliAmp range but was still several orders of magnitude lower than the on-state current capabilities of the devices under test. This increase must be considered in the design of circuits using power transistors at elevated temperature. Three circuit topologies have been prototyped using MOSFET's and IGBT's. The circuits were designed using zero current or zero voltage switching techniques to eliminate or minimize hard switching of the power transistors. These circuits have functioned properly over the temperature range. One thousand hour life data have been collected for two power supplies with no failures and no significant change in operating efficiency. While additional reliability testing should be conducted, the feasibility of designing soft switched circuits for operation at 200 C has been successfully demonstrated.

  5. Relative Age Affects Marathon Performance in Male and Female Athletes

    PubMed Central

    Connick, Mark J.; Beckman, Emma M.; Tweedy, Sean M.

    2015-01-01

    Marathon runners are ranked in 5-year age groups. However the extent to which 5-year groupings facilitates equitable competition has not been evaluated. The aim of this study was to evaluate the effect of relative age in male and female marathon running. Marathon finishing times for the top ten male (aged 20-69 years) and female athletes (aged 20-64 years) were obtained from the 2013 New York and Chicago marathons. Intra-class and inter-class validity were evaluated by comparing performances within (intra-class) and between (inter-class) the 5-year age groups. Results showed intra-class effects in all male age groups over 50 years, in all female age groups over 40 years, and in male and female 20-24 age groups (p < 0.05). Inter-class differences existed between the 20-24 and 25-29 age groups in both males and females, between all male age groups over 50 years, and between all female age groups over 40 years (p < 0.05). This study provided the first evaluation of the effects of relative age in male and female marathon running. The results provide preliminary but compelling evidence that the relatively older male athletes in age groups over 50 years and the relatively older females in age groups over 40 years are competitively disadvantaged compared to the younger athletes in these age groups. Key points Results showed a curvilinear relationship between age and marathon running performance with the negative effect of age becoming more pronounced in older runners. Relative age effects were found in all age groups over age 50 years in males and over age 40 years in females indicating that the relatively older runners were competitively disadvantaged compared to the relatively younger runners in these age groups. Relative age affected the 20-24 age classification which is consistent with the hypothesis that marathon performance improves until peak performance occurs in the 25-29 age classification. PMID:26336355

  6. Relative Age Affects Marathon Performance in Male and Female Athletes.

    PubMed

    Connick, Mark J; Beckman, Emma M; Tweedy, Sean M

    2015-09-01

    Marathon runners are ranked in 5-year age groups. However the extent to which 5-year groupings facilitates equitable competition has not been evaluated. The aim of this study was to evaluate the effect of relative age in male and female marathon running. Marathon finishing times for the top ten male (aged 20-69 years) and female athletes (aged 20-64 years) were obtained from the 2013 New York and Chicago marathons. Intra-class and inter-class validity were evaluated by comparing performances within (intra-class) and between (inter-class) the 5-year age groups. Results showed intra-class effects in all male age groups over 50 years, in all female age groups over 40 years, and in male and female 20-24 age groups (p < 0.05). Inter-class differences existed between the 20-24 and 25-29 age groups in both males and females, between all male age groups over 50 years, and between all female age groups over 40 years (p < 0.05). This study provided the first evaluation of the effects of relative age in male and female marathon running. The results provide preliminary but compelling evidence that the relatively older male athletes in age groups over 50 years and the relatively older females in age groups over 40 years are competitively disadvantaged compared to the younger athletes in these age groups. Key pointsResults showed a curvilinear relationship between age and marathon running performance with the negative effect of age becoming more pronounced in older runners.Relative age effects were found in all age groups over age 50 years in males and over age 40 years in females indicating that the relatively older runners were competitively disadvantaged compared to the relatively younger runners in these age groups.Relative age affected the 20-24 age classification which is consistent with the hypothesis that marathon performance improves until peak performance occurs in the 25-29 age classification.

  7. Factors affecting student performance in an undergraduate genetics course.

    PubMed

    Bormann, J Minick; Moser, D W; Bates, K E

    2013-05-01

    The objective of this study was to determine some of the factors that affect student success in a genetics course. Genetics for the Kansas State University College of Agriculture is taught in the Department of Animal Sciences and Industry and covers Mendelian inheritance, molecular genetics, and quantitative/population genetics. Data collected from 1,516 students over 7 yr included year and semester of the course; age; gender; state of residence; population of hometown; Kansas City metro resident or not; instructor of course; American College Testing Program (ACT) scores; number of transfer credits; major; college; preveterinary student or not; freshman, sophomore, junior, and senior grade point average (GPA); semester credits when taking genetics; class standing when enrolled in genetics; cumulative GPA before and after taking genetics; semester GPA in semester taking genetics, number of semesters between the biology prerequisite and genetics; grade in biology; location of biology course; and final percentage in genetics. Final percentage in genetics did not differ due to instructor, gender, state of residence, major, or college (P > 0.16). Transfer students tended to perform better than nontransfer students (P = 0.09), and students from the Kansas City metro outscored students from other areas (P = 0.03). Preveterinary option students scored higher in genetics than non-preveterinary students (P < 0.01). Seniors scored higher than juniors and sophomores, who scored higher than freshmen (P < 0.02). We observed a tendency for students with higher grades in biology to perform better in genetics (P = 0.06). Students who took biology at Kansas State University performed better in genetics than students who transferred the credit (P < 0.01). There was a negative regression of hometown population on score in genetics (P < 0.01), and positive regressions of ACT score, all measures of GPA, course load, and cumulative credits on final percentage in the course (P < 0.02). To

  8. Performance projections of alternative AMTEC systems and devices

    NASA Technical Reports Server (NTRS)

    Underwood, Mark L.; Williams, Roger M.; Jeffries-Nakamura, Barbara; Ryan, A. M.; O'Connor, Dennis

    1991-01-01

    The alkali metal thermoelectric converted (AMTEC) converts heat to electrical power without moving parts. Attention is presently given to two AMTEC devices that have been optimized for conversion efficiencies of the order of 30 percent or more at 1100 K, in conjunction with high volumetric power densities. A 'tube-bundle' AMTEC configuration yields a peak power of 426 W/l; a flat-plate AMTEC system yields 2.4 W/l.

  9. Highly temperature-dependent performance of a polyvinylidene fluoride Lamb wave device

    NASA Astrophysics Data System (ADS)

    Toda, Kohji; Ikenohira, Kazuo

    1980-11-01

    A Lamb wave device using a polyvinylidene flouride film is described. The transducer of the device consists of interdigital electrodes and a uniform counter-electrode. The performance of the device is highly temperature dependent. The attenuation of the Lamb wave on the film increases with higher frequencies. The attenuation decreases with increasing temperature, while the conversion efficiency of the transducer is nearly constant for the temperature change. The output of the device changes significantly under the influence of irradiation from a black body, and the device is very sensitive in the infrared region.

  10. Silicon device performance measurements to support temperature range enhancement

    NASA Technical Reports Server (NTRS)

    Johnson, R. Wayne; Askew, Ray; Bromstead, James; Weir, Bennett

    1991-01-01

    The results of the NPN bipolar transistor (BJT) (2N6023) breakdown voltage measurements were analyzed. Switching measurements were made on the NPN BJT, the insulated gate bipolar transistor (IGBT) (TA9796) and the N-channel metal oxide semiconductor field effect transistor (MOSFET) (RFH75N05E). Efforts were also made to build a H-bridge inverter. Also discussed are the plans that have been made to do life testing on the devices, to build an inductive switching test circuit and to build a dc/dc switched mode converter.

  11. Improved device performance by multistep or carbon Co-implants

    SciTech Connect

    Liefting, R. . MESA Research Inst. FOM Inst. for Atomic and Molecular Physics, Amsterdam ); Wijburg, R.C.M.; Wallinga, H. . MESA Research Inst.); Custer, J.S.; Saris, F.W. )

    1994-01-01

    High-energy ion implantation is used for forming the collector in vertical bipolar transistors in a BiCMOS process. Secondary defects, remaining after annealing the implant damage, give rise to an increased leakage current and to collector-emitter shorts. These shorts reduce the transistor yield. The use of multiple step implants or the introduction of a C gettering layer are demonstrated to avoid dislocation formation. Experimental results show that these schemes subsequently lower the leakage current and dramatically increase device yield. The presence of C can cause increased collector/substrate leakage, indicating that the C profile needs to be optimized with respect to the doping profiles.

  12. Performance of a Portable Sleep Monitoring Device in Individuals with High Versus Low Sleep Efficiency

    PubMed Central

    Markwald, Rachel R.; Bessman, Sara C.; Reini, Seth A.; Drummond, Sean P.A.

    2016-01-01

    Study Objectives: Portable and automated sleep monitoring technology is becoming widely available to consumers, and one wireless system (WS) has recently surfaced as a research tool for sleep and sleep staging assessment outside the hospital/laboratory; however, previous research findings indicate low sensitivity for wakefulness detection. Because difficulty discriminating between wake and sleep is likely to affect staging performance, we sought to further evaluate the WS by comparing it to the gold-standard polysomnography (PSG) and actigraphy (ACT) for overall sleep/wakefulness detection and sleep staging, within high and low sleep efficiency sleepers. Methods: Twenty-nine healthy adults (eight females) underwent concurrent WS, PSG, and ACT assessment in an overnight laboratory study. Epoch-by-epoch agreement was determined by comparing sleep/wakefulness decisions between the WS to both PSG and ACT, and for detection of light, deep, and rapid eye movement (REM) sleep stages between the WS and PSG. Results: Sensitivity for wakefulness was low (40%), and an overestimation of total sleep time and underestimation of wake after sleep onset was observed. Prevalence and bias adjusted kappa statistic indicated moderate-to-high agreement between the WS and PSG for sleep staging. However, upon further inspection, WS performance varied by sleep efficiency, with the best performance during high sleep efficiency. Conclusions: The benefit of the WS as a sleep monitoring device over ACT is the ability to assess sleep stages, and our findings suggest this benefit is only realized within high sleep efficiency. Care should be taken to collect data under conditions where this is expected. Citation: Markwald RR, Bessman SC, Reini SA, Drummond SP. Performance of a portable sleep monitoring device in individuals with high versus low sleep efficiency. J Clin Sleep Med 2016;12(1):95–103. PMID:26285110

  13. Item Context Factors Affecting Students' Performance on Mathematics Items

    ERIC Educational Resources Information Center

    Salgado, Felipe Almuna; Stacey, Kaye

    2014-01-01

    This paper reports how the context in which a mathematics item is embedded impacts on students' performance. The performance of Year 10 students on four PISA items was compared with performance on variants with more familiar contexts. Performance was not better when they solved items with more familiar contexts but there was some evidence that…

  14. Knowledge system and method for simulating chemical controlled release device performance

    DOEpatents

    Cowan, Christina E.; Van Voris, Peter; Streile, Gary P.; Cataldo, Dominic A.; Burton, Frederick G.

    1991-01-01

    A knowledge system for simulating the performance of a controlled release device is provided. The system includes an input device through which the user selectively inputs one or more data parameters. The data parameters comprise first parameters including device parameters, media parameters, active chemical parameters and device release rate; and second parameters including the minimum effective inhibition zone of the device and the effective lifetime of the device. The system also includes a judgemental knowledge base which includes logic for 1) determining at least one of the second parameters from the release rate and the first parameters and 2) determining at least one of the first parameters from the other of the first parameters and the second parameters. The system further includes a device for displaying the results of the determinations to the user.

  15. In-Field Performance Testing of Stormwater Treatment Devices

    EPA Science Inventory

    The Environmental Technology Verification (ETV) Program was created by EPA’s Office of Research and Development to facilitate the deployment of innovative or improved environmental technologies through performance verification and dissemination of information. The program’s goal ...

  16. Glassy materials for lithium batteries: electrochemical properties and devices performances

    NASA Astrophysics Data System (ADS)

    Duclot, Michel; Souquet, Jean-Louis

    Amorphous or glassy materials may be used as electrolyte or electrode materials for lithium primary or secondary batteries. A first generation proceeded from classical coin cells in which the organic electrolyte was replaced by a high lithium conductive glassy electrolyte. The solid components were assembled under isostatic pressure. The main advantages of such cells are a good storage stability and ability to operate until 200°C. Nevertheless, the high resistivity of the glassy electrolyte below room temperature and a limited depth for charge and discharge cycles makes these cells not competitive compared to conventional lithium-ion batteries. More promising, are the thin films solid state microbatteries realised by successive depositions of electrodes and electrolyte. The low resistance of the electrolyte amorphous layer allows cycling at temperatures as low as -10°C. The total thickness of thin film batteries, including packaging is less than 100 μm. A capacity of about 100 μAh cm -2 with over 10 4 charge-discharge cycles at 90% in depth of discharge is well suited for energy independent smart cards or intelligent labels, which represent for these devices a large and unrivalled market.

  17. FinFET Doping; Material Science, Metrology, and Process Modeling Studies for Optimized Device Performance

    SciTech Connect

    Duffy, R.; Shayesteh, M.

    2011-01-07

    In this review paper the challenges that face doping optimization in 3-dimensional (3D) thin-body silicon devices will be discussed, within the context of material science studies, metrology methodologies, process modeling insight, ultimately leading to optimized device performance. The focus will be on ion implantation at the method to introduce the dopants to the target material.

  18. Effects of Surface Composition on CdTe/CdS Device Performance

    SciTech Connect

    Levi, D.; Albin, D.; King, D.

    2000-01-01

    The atomic composition of the back surface of the CdTe layer in a CdTe/CdS photovoltiac (PV) device has a significant influence on the quality of the electrical contact to this layer. This paper reports the results of a systematic study that correlates the composition of the back surface with pre-contact processing and device performance.

  19. How Does Test Exemption Affect Schools' and Students' Academic Performance?

    ERIC Educational Resources Information Center

    Jennings, Jennifer L.; Beveridge, Andrew A.

    2009-01-01

    Analyzing data from a large urban district in Texas, this study examines how high-stakes test exemptions alter officially reported scores and asks whether test exemption has implications for the academic achievement of special education students. Test exemption inflated overall passing rates but especially affected the passing rates of African…

  20. Selected Factors Affecting the Performance Assessment of Elementary Teachers.

    ERIC Educational Resources Information Center

    Thomson, Scott

    1990-01-01

    This study determined whether nontraditional assessment factors (principal's gender, choice of subject matter for demonstrating competence, or years of teacher experience) would affect elementary teachers' scores when completing the Leon County (Florida) Teacher Assessment Process. Principal's gender and subject selected were significant…

  1. An Analysis of Team Composition as It Affects Simulation Performance.

    ERIC Educational Resources Information Center

    Krishnakumar, Parameswar; Chisholm, Thomas Alexander

    This study investigated the extent to which sex composition and average team academic achievement of student simulation teams affect team effectiveness. Seventy-four students in two sections of a marketing principles class were divided into 20 teams to test their decision-making skills. For 10 weeks, each team operated a simulated supermarket…

  2. Certain Organizational Characteristics Affect ACO Preventive Care Quality Performance.

    PubMed

    Ticse, Caroline

    2016-06-01

    Key findings. (1) ACOs at provider workforce extremes--few primary care providers or many specialists--performed worse on measures of preventive care quality relative to those with more PCPs and fewer specialists. (2) Upfront investment in ACO formation is associated with higher performance in preventive care quality. (3) ACOs with a higher proportion of minority beneficiaries performed worse on disease prevention measures than did ACOs with a lower proportion of minority beneficiaries. (4) ACOs facing barriers to quality performance may benefit from organizational characteristics such as electronic health record capabilities and hospital inclusion in the ACO.

  3. Efficacy of commercially available ultrasonic pest repellent devices to affect behavior of bed bugs (Hemiptera: Cimicidae).

    PubMed

    Yturralde, K M; Hofstetter, R W

    2012-12-01

    Little is known about the potential for acoustic communication in bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), or the use of sound as cues in host location, although many hemipterans are known to communicate with sound. Most behavioral research has focused on bed bug pheromones that are used in aggregation and as alarm signals. We investigated the influence of sound as a deterrent and as an attractant, either of which could ultimately be used to monitor and control bed bugs. Female bed bugs were tested in two-choice tests with four different commercially available ultrasonic repellent devices. We found that female bed bugs were equally likely to occur in arenas with or without sound produced by ultrasonic devices. These devices did not repel or attract bed bugs during choice trials. However, more bed bugs preferred the middle corridor between the test (sound) and control (no sound) arenas when the sound devices were played. Bed bugs were also more likely to exit the middle corridor during control trials compared with treatment trials with ultrasonic devices. Our results confirm that commercial devices producing ultrasound are not a promising tool for repelling bed bugs.

  4. Performance Assessment of Communication Enhancement Devices TEA HI Threat Headset

    DTIC Science & Technology

    2015-08-01

    Figure 13. Placement of ATFs and free-field pressure transducer Pressure measurements were recorded using 16-bit digital recorders at a sampling ...response was recorded , the LEDs of the target speaker were activated to give the subject feedback on his/her performance. Each of the 8 subjects...on the target speaker the subject would respond by pressing either the blue or green button (Figure 20). After the subject recorded his/her response

  5. Learners' Metalinguistic and Affective Performance in Blogging to Write

    ERIC Educational Resources Information Center

    Chen, Ping-Ju

    2016-01-01

    The documentation of the benefits of blog use in foreign language education has proliferated since 2006. In the field of blogging to write, most studies focus on learners' linguistic performance and perceptions. To provide an analysis of learners' writing performance by using blogs, in addition to the often-researched areas, this study examines…

  6. Young Children's Knowledge About Effects of Affect on Performance.

    ERIC Educational Resources Information Center

    Pierce, Jean W.

    1985-01-01

    Addresses the issue of whether preschoolers are aware of the connection between their emotions, their performance on a task of eye-hand coordination, and their evaluation of the task and their performance. Results indicate a developmental trend that children's predictions conform more to mood congruity theory as they grow older. (Author/DST)

  7. Method of testing active latent-heat storage devices based on thermal performance. (ASHRAE standard)

    SciTech Connect

    1985-01-26

    The purpose of this standard is to provide a standard procedure for determining the thermal performance of latent heat thermal energy storage devices used in heating, air-conditioning, and service hot water systems.

  8. Performance Enhancement of Electronic and Energy Devices via Block Copolymer Self-Assembly.

    PubMed

    Yoo, Hyeon Gyun; Byun, Myunghwan; Jeong, Chang Kyu; Lee, Keon Jae

    2015-07-15

    The use of self-assembled block copolymers (BCPs) for the fabrication of electronic and energy devices has received a tremendous amount of attention as a non-traditional approach to patterning integrated circuit elements at nanometer dimensions and densities inaccessible to traditional lithography techniques. The exquisite control over the dimensional features of the self-assembled nanostructures (i.e., shape, size, and periodicity) is one of the most attractive properties of BCP self-assembly. Harmonic spatial arrangement of the self-assembled nanoelements at desired positions on the chip may offer a new strategy for the fabrication of electronic and energy devices. Several recent reports show the great promise in using BCP self-assembly for practical applications of electronic and energy devices, leading to substantial enhancements of the device performance. Recent progress is summarized here, with regard to the performance enhancements of non-volatile memory, electrical sensor, and energy devices enabled by directed BCP self-assembly.

  9. Performance Modeling of Network-Attached Storage Device Based Hierarchical Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Menasce, Daniel A.; Pentakalos, Odysseas I.

    1995-01-01

    Network attached storage devices improve I/O performance by separating control and data paths and eliminating host intervention during the data transfer phase. Devices are attached to both a high speed network for data transfer and to a slower network for control messages. Hierarchical mass storage systems use disks to cache the most recently used files and a combination of robotic and manually mounted tapes to store the bulk of the files in the file system. This paper shows how queuing network models can be used to assess the performance of hierarchical mass storage systems that use network attached storage devices as opposed to host attached storage devices. Simulation was used to validate the model. The analytic model presented here can be used, among other things, to evaluate the protocols involved in 1/0 over network attached devices.

  10. Emissions from premixed charge compression ignition (PCCI) combustion and affect on emission control devices

    SciTech Connect

    Parks, II, James E; Kass, Michael D; Huff, Shean P; Barone, Teresa L; Lewis Sr, Samuel Arthur; Prikhodko, Vitaly Y; Storey, John Morse

    2010-01-01

    A light-duty diesel engine has been operated in advanced combustion modes known generally as premixed charge compression ignition (PCCI). The emissions have been characterized for several load and speed combinations. Fewer NO{sub x} and particulate matter (PM) emissions are produced by PCCI, but higher CO and hydrocarbon (HC) emissions result. In addition, the nature of the PM differs from conventional combustion; the PM is smaller and has a much higher soluble organic fraction (SOF) content (68% vs. 30% for conventional combustion). Three catalyst technologies were studied to determine the affects of HECC on catalyst performance; the technologies were a lean NO{sub x} trap (LNT), diesel oxidation catalyst (DOC), and diesel particulate filter (DPF). The LNT benefited greatly from the reduced NO{sub x} emissions associated with PCCI. NO{sub x} capacity requirements are reduced as well as overall tailpipe NO{sub x} levels particularly at low load and temperature conditions where regeneration of the LNT is difficult. The DOC performance requirements for PCCI are more stringent due to the higher CO and HC emissions; however, the DOC was effective at controlling the higher CO and HC emissions at conditions above the light-off temperature. Below light-off, CO and HC emissions are problematic. The study of DPF technology focused on the fuel penalties associated with DPF regeneration or 'desoot' due to the different PM loading rates from PCCI vs. conventional combustion. Less frequent desoot events were required from the lower PM from PCCI and, when used in conjunction with an LNT, the lower PM from less frequent LNT regeneration. The lower desoot frequency leads a {approx}3% fuel penalty for a mixture of PCCI and conventional loads vs. {approx}4% for conventional only combustion.

  11. Performance improvements of symmetry-breaking reflector structures in nonimaging devices

    DOEpatents

    Winston, Roland

    2004-01-13

    A structure and method for providing a broken symmetry reflector structure for a solar concentrator device. The component of the optical direction vector along the symmetry axis is conserved for all rays propagated through a translationally symmetric optical device. This quantity, referred to as the translational skew invariant, is conserved in rotationally symmetric optical systems. Performance limits for translationally symmetric nonimaging optical devices are derived from the distributions of the translational skew invariant for the optical source and for the target to which flux is to be transferred. A numerically optimized non-tracking solar concentrator utilizing symmetry-breaking reflector structures can overcome the performance limits associated with translational symmetry.

  12. CT-automatic exposure control devices: What are their performances?

    NASA Astrophysics Data System (ADS)

    Gutierrez, Daniel; Schmidt, Sabine; Denys, Alban; Schnyder, Pierre; Bochud, François O.; Verdun, Francis R.

    2007-10-01

    PurposeTo avoid unnecessary exposure to the patients, constructors have developed tube current modulation algorithms. The purpose of this work is to assess the performance of computed tomography (CT) tube current modulation concerning patient dose and image noise in MSCT scanners. Material and methodsA conical PMMA phantom with elliptical cross-section, to vary the thickness of the irradiated object in a monotonous way, and an anthropomorphic chest phantom were scanned under similar conditions on a general electrics (GE) LightSpeed VCT (64 slices) scanner. Noise measurements were made by calculating the standard deviation of the CT-number on a homogeneous ROI in both phantoms. The dose was estimated with the parameters read in the DICOM header of each studied image. ResultsThe study has shown that most of the time, constant noise levels (noise index) can be obtained by a variation of the mA. Nevertheless, this adaptation can be not fast enough when the variation of the attenuation changes is rapid. Thus, an adaptation length up to 5 cm was obtained. A 18% dose reduction can be achieved (mean of 9.9%) by switching from z-axis modulation algorithm to xyz-axis modulation option. However, exposure in the chest area can be higher with current modulation than without, when trying to keep an image noise level constant in thoraco-abdominal investigations. ConclusionCurrent modulation algorithms can produce inadequate quality images due to problems with tube current stabilization when a sudden attenuation variation takes place as at the start of a scanning sequence. As expected, rotational ( xyz-axis) modulation performs better than only z-axis modulation algorithm. The use of automatic exposure control (AEC) can lead to an increase of the dose if the maximum allowed current is not properly set in thoraco-abdominal acquisitions.

  13. Effects of traps and polarization charges on device performance of AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Hussein, A. SH.; Ghazai, Alaa J.; Salman, Emad A.; Hassan, Z.

    2013-11-01

    This paper presents the simulated electrical characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) by using ISE TCAD software. The effects of interface traps, bulk traps and polarization charges are investigated. It was observed that the role and dynamic of traps affect the device performance which requires a precondition to calculate the DC characteristics that are in agreement with the experimental data. On the other hand, polarization charges lead to quantum confinement of the electrons in the channel and form two-dimensional electron gas. The electron quantization leads to increasing the drain current and shift in the threshold voltage. The device performance can be improved by optimizing the fixed interface charge and thus reducing the bulk traps to enhance the DC characteristics.

  14. Aversive Pavlovian Responses Affect Human Instrumental Motor Performance

    PubMed Central

    Rigoli, Francesco; Pavone, Enea Francesco; Pezzulo, Giovanni

    2012-01-01

    In neuroscience and psychology, an influential perspective distinguishes between two kinds of behavioral control: instrumental (habitual and goal-directed) and Pavlovian. Understanding the instrumental-Pavlovian interaction is fundamental for the comprehension of decision-making. Animal studies (as those using the negative auto-maintenance paradigm), have demonstrated that Pavlovian mechanisms can have maladaptive effects on instrumental performance. However, evidence for a similar effect in humans is scarce. In addition, the mechanisms modulating the impact of Pavlovian responses on instrumental performance are largely unknown, both in human and non-human animals. The present paper describes a behavioral experiment investigating the effects of Pavlovian conditioned responses on performance in humans, focusing on the aversive domain. Results showed that Pavlovian responses influenced human performance, and, similar to animal studies, could have maladaptive effects. In particular, Pavlovian responses either impaired or increased performance depending on modulator variables such as threat distance, task controllability, punishment history, amount of training, and explicit punishment expectancy. Overall, these findings help elucidating the computational mechanisms underlying the instrumental-Pavlovian interaction, which might be at the base of apparently irrational phenomena in economics, social behavior, and psychopathology. PMID:23060738

  15. Environmental context change affects memory for performed actions.

    PubMed

    Sahakyan, Lili

    2010-03-01

    The current study investigated the effect of environmental context change between the study and test on the recall of action phrases that either were performed during encoding (subject-performed tasks, SPTs) or were verbally encoded (verbal tasks, VTs). Both SPTs and VTs showed the same magnitude of impaired recall when the study and test contexts mismatched. Furthermore, changing the context between the two study lists reduced cross-list intrusion errors compared to encoding the lists in the same context. Both SPTs and VTs benefited from studying the lists in different contexts as evidenced by reduced intrusions. Taken together, the results suggest that SPTs are integrated with their context because they suffered when context changed between the study and test, and they also benefited when they were performed in two environments versus the same environment.

  16. Wheat gluten hydrolysate affects race performance in the triathlon.

    PubMed

    Koikawa, Natsue; Aoki, Emi; Suzuki, Yoshio; Sakuraba, Keishoku; Nagaoka, Isao; Aoki, Kazuhiro; Shimmura, Yuki; Sawaki, Keisuke

    2013-07-01

    Wheat gluten hydrolysate (WGH) is a food ingredient, prepared by partial enzymatic digestion of wheat gluten, which has been reported to suppress exercise-induced elevation of serum creatinine kinase (CK) activity. However, its effects on athletic performance have not yet been elucidated. This is the presentation of an experiment performed on five female college triathletes who completed an Olympic distance triathlon with or without ingestion of 21 g of WGH during the cycling leg. The experiment was performed in a crossover double-blind manner. The race time of the running leg and thus the total race time was significantly shorter when WGH was ingested. However, serum CK levels exhibited no apparent differences between the two WGH or placebo groups.

  17. When children affect parents: Children's academic performance and parental investment.

    PubMed

    Yurk Quadlin, Natasha

    2015-07-01

    Sociologists have extensively documented the ways that parent resources predict children's achievement. However, less is known about whether and how children's academic performance shapes parental investment behaviors. I use data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) and longitudinal fixed effects models to examine how changes in teacher assessments are related to changes in the conferral of various parent resources. Overall, I find that the relationship between achievement and investment varies based on the directionality in children's achievement and the type of resource at hand. Children whose performance improves receive a broad range of enrichment resources, while declines in performance are met with corrective educational resources. Results are largely consistent whether language or math assessments are used to predict investment, and also among children whose achievement does not change over time. I discuss these patterns, along with implications for the use of parent resources in education and family research.

  18. Monolayer-Mediated Growth of Organic Semiconductor Films with Improved Device Performance.

    PubMed

    Huang, Lizhen; Hu, Xiaorong; Chi, Lifeng

    2015-09-15

    Increased interest in wearable and smart electronics is driving numerous research works on organic electronics. The control of film growth and patterning is of great importance when targeting high-performance organic semiconductor devices. In this Feature Article, we summarize our recent work focusing on the growth, crystallization, and device operation of organic semiconductors intermediated by ultrathin organic films (in most cases, only a monolayer). The site-selective growth, modified crystallization and morphology, and improved device performance of organic semiconductor films are demonstrated with the help of the inducing layers, including patterned and uniform Langmuir-Blodgett monolayers, crystalline ultrathin organic films, and self-assembled polymer brush films. The introduction of the inducing layers could dramatically change the diffusion of the organic semiconductors on the surface and the interactions between the active layer with the inducing layer, leading to improved aggregation/crystallization behavior and device performance.

  19. Power electronics performance in cryogenic environment: evaluation for use in HTS power devices

    NASA Astrophysics Data System (ADS)

    Pereira, P.; Valtchev, S.; Pina, J.; Gonçalves, A.; Ventim Neves, M.; Rodrigues, A. L.

    2008-02-01

    Power electronics (PE) plays a major role in electrical devices and systems, namely in electromechanical drives, in motor and generator controllers, and in power grids, including high-voltage DC (HVDC) power transmission. PE is also used in devices for the protection against grid disturbances, like voltage sags or power breakdowns. To cope with these disturbances, back-up energy storage devices are used, like uninterruptible power supplies (UPS) and flywheels. Some of these devices may use superconductivity. Commercial PE semiconductor devices (power diodes, power MOSFETs, IGBTs, power Darlington transistors and others) are rarely (or never) experimented for cryogenic temperatures, even when designed for military applications. This means that its integration with HTS power devices is usually done in the hot environment, raising several implementation restrictions. These reasons led to the natural desire of characterising PE under extreme conditions, e. g. at liquid nitrogen temperatures, for use in HTS devices. Some researchers expect that cryogenic temperatures may increase power electronics' performance when compared with room-temperature operation, namely reducing conduction losses and switching time. Also the overall system efficiency may increase due to improved properties of semiconductor materials at low temperatures, reduced losses, and removal of dissipation elements. In this work, steady state operation of commercial PE semiconductors and devices were investigated at liquid nitrogen and room temperatures. Performances in cryogenic and room temperatures are compared. Results help to decide which environment is to be used for different power HTS applications.

  20. Reynolds Number Effects on the Performance of Lateral Control Devices

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.

    2000-01-01

    The influence of Reynolds number on the performance of outboard spoilers and ailerons was investigated on a generic subsonic transport configuration in the National Transonic Facility over a chord Reynolds number range 41 from 3x10(exp 6) to 30xl0(exp 6) and a Mach number range from 0.50 to 0.94, Spoiler deflection angles of 0, 10, 15, and 20 deg and aileron deflection angles of -10, 0, and 10 deg were tested. Aeroelastic effects were minimized by testing at constant normalized dynamic pressure conditions over intermediate Reynolds number ranges. Results indicated that the increment in rolling moment due to spoiler deflection generally becomes more negative as the Reynolds number increases from 3x10(exp 6) to 22x10(exp 6) with only small changes between Reynolds numbers of 22x10(exp 6) and 30x10(exp 6). The change in the increment in rolling moment coefficient with Reynolds number for the aileron deflected configuration is generally small with a general trend of increasing magnitude with increasing Reynolds number.

  1. Teacher Dispositions Affecting Self-Esteem and Student Performance

    ERIC Educational Resources Information Center

    Helm, Carroll

    2007-01-01

    Research supports several factors related to student success. Darling-Hammond (2000) indicated that the quality of teachers, as measured by whether the teachers were fully certified and had a major in their teaching field, was related to student performance. Measures of teacher preparation and certification were the strongest predictors of student…

  2. Factors Affecting Student Performance in Law School Economics Courses.

    ERIC Educational Resources Information Center

    Siegfried, John J.

    1981-01-01

    Noting the increasing role of economics in the law, many law schools have introduced formal economics instruction into their curricula. Several of the controversies surrounding liberal arts courses taught in law schools are examined. Prior formal coursework in the subject appeared to have no relationship to course performance. (MLW)

  3. Factors Affecting School District Performance Scores in Louisiana

    ERIC Educational Resources Information Center

    Harrison, Ronnie

    2010-01-01

    The purpose of this study was to investigate the relationship between District Performance Scores (DPS) in Louisiana and (a) socio-economic status of students, (b) academic achievement using average ACT scores, (c) percentage of certified teachers, (d) district class size, (e) per pupil expenditure, and (f) percentage of minority students in…

  4. Performativity and Affectivity: Lesson Observations in England's Further Education Colleges

    ERIC Educational Resources Information Center

    Edgington, Ursula

    2013-01-01

    Teaching and learning observations (TLOs) are used in educational environments worldwide to measure and improve quality and support professional development. TLOs can be positive for teachers who enjoy opportunities to "perform" their craft and/or engage in professional dialogue. However, if this crucial, collaborative developmental…

  5. Does Participative Decision Making Affect Lecturer Performance in Higher Education?

    ERIC Educational Resources Information Center

    Sukirno, D. S.; Siengthai, Sununta

    2011-01-01

    Purpose: The relationship between participation and job performance has captured the interest of not only business researchers but also education researchers. However, the topic has not gained significant attention in the educational management research arena. The purpose of this paper is to empirically examine the impact of participation in…

  6. How Motivation Affects Academic Performance: A Structural Equation Modelling Analysis

    ERIC Educational Resources Information Center

    Kusurkar, R. A.; Ten Cate, Th. J.; Vos, C. M. P.; Westers, P.; Croiset, G.

    2013-01-01

    Few studies in medical education have studied effect of quality of motivation on performance. Self-Determination Theory based on quality of motivation differentiates between Autonomous Motivation (AM) that originates within an individual and Controlled Motivation (CM) that originates from external sources. To determine whether Relative Autonomous…

  7. Unit Cohesion and the Surface Navy: Does Cohesion Affect Performance

    DTIC Science & Technology

    1989-12-01

    Relationship of Group Cohe- sion to Group Performance: A Research Integration Attempt, by L. W. Oliver, A199069, July 1988. Cartwright , D., "The Nature of...Group Cohesiveness," in Darwin Cart- wright and Alvin Zander, eds., Group Dynamics: Research and Theory, New York: Harper and Row, 1968. Gujarati, D. N

  8. How Does the Use of Mobile Devices Affect Teachers' Perceptions on Mobile Learning?

    ERIC Educational Resources Information Center

    Kim, Dong-Joong; Kim, Daesang; Choi, Sang-Ho

    2016-01-01

    The purpose of this study is to investigate the potential impact and effectiveness of mobile learning in the context of a flipped classroom and also address implications for future curriculum design. The researchers developed a mathematics curriculum featuring the use of mobile devices in the context of a flipped classroom. Thirty pre-service…

  9. 78 FR 58316 - Complex Issues in Developing Medical Devices for Pediatric Patients Affected by Rare Diseases...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... HUMAN SERVICES Food and Drug Administration Complex Issues in Developing Medical Devices for Pediatric... (FDA) is announcing the following public workshop entitled ``Complex Issues in Developing Medical... ``Complex Issues in Developing Drug and Biological Products for Rare Diseases.'' The purpose of the...

  10. Temperature changes in exhaled breath condensate collection devices affect observed acetone concentrations.

    PubMed

    Loyola, Bryan R; Bhushan, Abhinav; Schivo, Michael; Kenyon, Nicholas J; Davis, Cristina E

    2008-09-01

    Chemical analysis of exhaled breath condensate (EBC) is an emerging method to non-invasively identify and measure potential biomarkers of disease. Various EBC collection methods have been proposed, each with strengths and weaknesses. Recent evidence in the literature suggests that sample collection methodologies could introduce potential artifacts in biomarker measurements. In this study, we tested the effect of thermal changes during condensate collection on measured EBC chemical concentrations. Using both actively-cooled and passively-cooled devices, we measured distinct differences in the amount of condensate that can be collected over discrete time periods. We also found that concentrations of acetone varied with the thermal profile changes in the collection devices, in apparently identical EBC samples. Together, this evidence suggests that great care should be taken to standardize EBC collection methods, and that small deviations in the thermal properties of the collection devices could contribute to confounding EBC measurement artifacts. This has implications for the design and development of future portable breath analysis systems, especially miniature hand-held devices.

  11. Does familiarity with computers affect computerized neuropsychological test performance?

    PubMed

    Iverson, Grant L; Brooks, Brian L; Ashton, V Lynn; Johnson, Lynda G; Gualtieri, C Thomas

    2009-07-01

    The purpose of this study was to determine whether self-reported computer familiarity is related to performance on computerized neurocognitive testing. Participants were 130 healthy adults who self-reported whether their computer use was "some" (n = 65) or "frequent" (n = 65). The two groups were individually matched on age, education, sex, and race. All completed the CNS Vital Signs (Gualtieri & Johnson, 2006b) computerized neurocognitive battery. There were significant differences on 6 of the 23 scores, including scores derived from the Symbol-Digit Coding Test, Stroop Test, and the Shifting Attention Test. The two groups were also significantly different on the Psychomotor Speed (Cohen's d = 0.37), Reaction Time (d = 0.68), Complex Attention (d = 0.40), and Cognitive Flexibility (d = 0.64) domain scores. People with "frequent" computer use performed better than people with "some" computer use on some tests requiring rapid visual scanning and keyboard work.

  12. Scales affect performance of Monarch butterfly forewings in autorotational flight

    NASA Astrophysics Data System (ADS)

    Demko, Anya; Lang, Amy

    2012-11-01

    Butterfly wings are characterized by rows of scales (approximately 100 microns in length) that create a shingle-like pattern of cavities over the entire surface. It is hypothesized that these cavities influence the airflow around the wing and increase aerodynamic performance. A forewing of the Monarch butterfly (Danus plexippus) naturally undergoes autorotational flight in the laminar regime. Autorotational flight is an accurate representation of insect flight because the rotation induces a velocity gradient similar to that found over a flapping wing. Drop test flights of 22 forewings before and after scale removal were recorded with a high-speed camera and flight behavior was quantified. It was found that removing the scales increased the descent speed and decreased the descent factor, a measure of aerodynamic efficacy, suggesting that scales increased the performance of the forewings. Funded by NSF REU Grant 1062611.

  13. Neuroticism Negatively Affects Multitasking Performance through State Anxiety

    DTIC Science & Technology

    2009-02-01

    interruptions, is greater than ever. As a result, multitasking has become a necessity in both home and work life for many individuals (e.g., Bühner...at work and at home . As such, researchers have begun to focus attention on understanding and predicting multitasking performance. Though past...technological innovation, and information overload, the pace of life is rapidly increasing. The pressure to do more in less time, often with frequent

  14. Personality Factors Affecting Pilot Combat Performance: A Preliminary Investigation

    DTIC Science & Technology

    1997-09-01

    collected by personnel from Metrica , Inc., under Contract F33615-91-D-0010 (Delivery Order 0005) sponsored by the Air Force Armstrong Laboratory. The...authors would like to thank ’their colleagues at Metrica for their contributions to . this effort; in particular, Mr John Quebe and Mr Martin Dittmar...aircrew combat performance. San Antonio TX: Metrica Inc. 7 . Dolgin, D.L., & Gibb, G.D. (1988). Personality assessment in aviator selection (NAMRL

  15. Luminance controlled pupil size affects Landolt C task performance

    SciTech Connect

    Berman, S.M. ); Fein, G. ); Jewett, D.L.; Ashford, F. )

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m[sup 2] and 73 cd/m[sup 2]. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  16. Luminance controlled pupil size affects Landolt C task performance. Revision

    SciTech Connect

    Berman, S.M.; Fein, G.; Jewett, D.L.; Ashford, F.

    1993-02-01

    Subjects judged the orientation of a 2 min. gap Landolt C located at a distance of 2.4 m. The stimuli were presented in central vision on a CRT, at low to medium contrast. The effects of varying the spectrum and luminance of surround lighting were assessed on both pupil size (measured using infrared pupillometry during task performance) and task accuracy. The task display was protected from the surround lighting, so that its luminance and contrast could be varied independently of the changes in the surround lighting. Indirect surround illumination was provided by either two illuminants of very different scotopic spectral content but with the same photopic luminance (Experiments 1 and 3), or by using the same illuminant at two different luminance levels (Experiment 2). In Experiment 3, the effect of changing surround spectrum was compared to the effect of varying task background luminance between 12 cd/m{sup 2} and 73 cd/m{sup 2}. In all experiments, scotopically enhanced surround lighting produced pupil areas which were reduced by almost 50% in comparison with surround lighting with relatively less scotopic luminance. Concomitantly there was improvement in Landolt C task performance with the scotopically enhanced surround lighting at all contrast and luminance levels. In these experiments, smaller pupil sizes were associated with significantly better visual-task performance in spite of lower task retinal illuminance when compared to the condition with larger pupils. These results suggest that changes in surround spectrum can compensate for the effect on task performance of a reduction in task luminance and supports the hypothesis that lighting energy savings could accrue in the workplace by shifting lamp spectra to obtain greater scotopic efficacy.

  17. Effect of two yellow delta-emitting layers on device performance of phosphorescent white organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Zhao, Juan; Yu, Junsheng; Wang, Xiao; Zhang, Lei

    2013-03-01

    Phosphorescent white organic light-emitting devices (WOLEDs) with a structure of ITO/TAPC/δ-EML1/mCP:FIrpic/δ-EML2/Bphen/Mg:Ag were fabricated, wherein two ultrathin and host-free emitting layers (EMLs) were formed by using yellow bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2'] iridium (acetylacetonate) [(tbt)2Ir(acac)] and referred to as delta-EMLs (δ-EML1 and δ-EML2). By adjusting the thicknesses of δ-EMLs, a maximum current efficiency of 27.6 cd/A, an external quantum efficiency (EQE) of 10%, together with low efficiency roll-off at high luminance were achieved. The results showed that δ-EML1 played a dominant role on charge carrier trapping, while δ-EML2 had major impact on yellow light emission, which were highly sensitive to the location of δ-EMLs. Furthermore, by introducing 5-nm Au as anode modifying layer, high device efficiency was maintained along with excellent color stability of warm white emission, displaying color coordinates of (0.38, 0.42) and color temperature of 4348 K at a luminance of 7000 cd/m2. Importantly, explanation and analysis for the influence of both ultrathin δ-EMLs and anode modifying layer on device performance were proposed.

  18. Factors That Affect Academic Performance Among Pharmacy Students

    PubMed Central

    Sansgiry, Sujit S.; Bhosle, Monali; Sail, Kavita

    2006-01-01

    Objective The objective of this study was to examine factors such as academic competence, test competence, time management, strategic studying, and test anxiety, and identify whether these factors could distinguish differences among students, based on academic performance and enrollment in the experiential program. Methods A cross-sectional study design utilizing questionnaires measuring previously validated constructs was used to evaluate the effect of these factors on students with low and high cumulative grade point averages (GPAs). Pharmacy students (N = 198) enrolled at the University of Houston participated in the study. Results Academic performance was significantly associated with factors such as academic competence and test competence. Students with a cumulative GPA of 3.0 or greater significantly differed in their level of test competence than those with a GPA of less than 3.0. Students enrolled in their experiential year differed from students enrolled in their second year of curriculum on factors such as test anxiety, academic competence, test competence, and time management skills. Conclusion Test competence was an important factor to distinguish students with low vs. high academic performance. Factors such as academic competence, test competence, test anxiety and time management improve as students' progress in their experiential year. PMID:17149433

  19. High performance nonvolatile memory devices based on Cu2-xSe nanowires

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Yan; Wu, Yi-Liang; Wang, Wen-Jian; Mao, Dun; Yu, Yong-Qiang; Wang, Li; Xu, Jun; Hu, Ji-Gang; Luo, Lin-Bao

    2013-11-01

    We report on the rational synthesis of one-dimensional Cu2-xSe nanowires (NWs) via a solution method. Electrical analysis of Cu2-xSe NWs based memory device exhibits a stable and reproducible bipolar resistive switching behavior with a low set voltage (0.3-0.6 V), which can enable the device to write and erase data efficiently. Remarkably, the memory device has a record conductance switching ratio of 108, much higher than other devices ever reported. At last, a conducting filaments model is introduced to account for the resistive switching behavior. The totality of this study suggests that the Cu2-xSe NWs are promising building blocks for fabricating high-performance and low-consumption nonvolatile memory devices.

  20. Electromyographical comparison of plank variations performed with and without instability devices.

    PubMed

    Snarr, Ronald L; Esco, Michael R

    2014-11-01

    Although there are multiple studies involving abdominal musculature activation and instability devices (e.g., Swiss balls), there is minimal research comparing them with a suspension device (e.g., TRX). The purpose of this investigation was to measure the electromyographical (EMG) activity of the rectus abdominis (RA), external oblique (EO), and erector spinae while performing planks with and without multiple instability devices. Twelve apparently healthy men (n = 6; age = 23.92 ± 3.64 years) and women (n = 6; age = 22.57 ± 1.87 years) volunteered to participate in this study. All participants performed 2 isometric contractions of 5 different plank variations, with or without an instability device, where the order of the exercises was randomized. Mean peak and normalized EMG of the RA, EO, and erector spinae musculature were compared across the 5 exercises. Results indicated that planks performed with the instability devices increased EMG activity in the superficial musculature when compared with traditional stable planks. Therefore, a traditional plank performed on a labile device may be considered an advanced variation and appropriate for use when a greater challenge is warranted. However, caution should be taken for those individuals with a history or weakness in the lumbar region due to the increases in erector spinae activation during instability planks.

  1. Positive affective tone and team performance: The moderating role of collective emotional skills.

    PubMed

    Collins, Amy L; Jordan, Peter J; Lawrence, Sandra A; Troth, Ashlea C

    2016-01-01

    Research on affect as a group-level phenomenon has shown that over time, individual members within a group become highly similar in their affect (i.e., members experience and display similar emotions and moods), and often become similar enough that the aggregation of individuals' affect can meaningfully represent the "affective tone" of the group. It is generally assumed that a more positive affective tone will lead to better team performance. We challenge the conclusion that positive affective tone is always good for team performance, suggesting that the relationship between positive affective tone and team performance is subject to moderating influences. Across two studies, we demonstrate that the self-reported collective emotional skills of team members play a crucial role in determining whether positive affective tone is beneficial or detrimental to team performance. Implications for theory and practice are discussed.

  2. Characterization of titanium dioxide: Factors affecting photocatalytic performance

    SciTech Connect

    Presley, R.W.

    1995-06-01

    Titanium dioxide is being evaluated as a photocatalyst in the destruction of contaminants in aqueous waste streams. Commercial samples of TiO{sub 2} powder have been obtained for base line studies of the photocatalytic destruction of salicylic acid standards. These commercial samples have been prepared by flame hydrolysis and aerosol or spray pyrolysis. Additional samples of TiO{sub 2} have been prepared in house by precipitation from TiCl{sub 4} in aqueous solution, some with the addition of dopants. X-ray powder diffraction data analysis indicates the predominate phase of these commercial and prepared powders to be anatase. A minor amount of the rutile crystalline phase of TiO{sub 2} was observed at various levels in some of these catalysts. The broadness of the x-ray diffraction bands varied among the samples analyzed and indicated the primary particle size to be within the 500 to 1,000 angstrom range with the product produced in house having the smallest crystallite size. Experiments were then performed to assess the photocatalytic performance of these various types of catalyst in the destruction of 30 ppm salicylic acid in deionized water.

  3. Different experimental protocols for decontamination affect the cleaning of medical devices. A preliminary electron microscopy analysis.

    PubMed

    Tessarolo, F; Caola, I; Fedel, M; Stacchiotti, A; Caciagli, P; Guarrera, G M; Motta, A; Nollo, G

    2007-04-01

    The aim of the present study was to examine the efficiency of different decontamination-cleaning protocols on blood-soiled catheters used for interventional cardiology. Electrophysiology and cardiac ablation disposable devices were contaminated with bacteria-spiked human blood and underwent four different pre-sterilization protocols, including a chlorine-releasing agent, a polyphenolic emulsion, and an enzymatic detergent. Treated samples were examined by optical microscopy, scanning electron microscopy and transmission electron microscopy to identify and characterize biological and inorganic residuals. The use of chlorine as a first treatment caused denaturation of serum proteins and adherence of blood components to the surface of the device, thus hindering the cleaning efficiency of subsequent treatments with enzymatic detergents. An enzymatic/chlorine protocol was more efficient, but was considered to be a greater risk to healthcare staff. Polyphenolic-based treatments had the highest level of efficiency in bioburden removal, but interaction and adsorption of this class of chemicals onto biopolymers might lead to serious concerns about toxicity on subsequent reuse. Adequate pre-sterilization cleaning is fundamental for sterilization success and high-resolution electron microscopy can provide significant and detailed information about the efficiency of chemicals used for cleaning a blood-soiled device.

  4. Performance enhancement of organic photovoltaic devices enabled by Au nanoarrows inducing surface plasmonic resonance effect.

    PubMed

    Li, Shujun; Li, Zhiqi; Zhang, Xinyuan; Zhang, Zhihui; Liu, Chunyu; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2016-09-21

    The surface plasmon resonance (SPR) effect of metal nanoparticles is widely employed in organic solar cells to enhance device performance. However, the light-harvesting improvement is highly dependent on the shape of the metal nanoparticles. In this study, the significantly enhanced performance upon incorporation of Au nanoarrows in solution-processed organic photovoltaic devices is demonstrated. Incorporating Au nanoarrows into the ZnO cathode buffer layer results in superior broadband optical absorption improvement and a power conversion efficiency of 7.82% is realized with a 27.3% enhancement compared with the control device. The experimental and theoretical results indicate that the introduction of Au nanoarrows not only increases optical trapping by the SPR effect but also facilitates exciton generation, dissociation, and charge transport inside the thin film device.

  5. Restorative effect of oxygen annealing on device performance in HfIZO thin-film transistors

    NASA Astrophysics Data System (ADS)

    Ha, Tae-Jun

    2015-03-01

    Metal-oxide based thin-film transistors (oxide-TFTs) are very promising for use in next generation electronics such as transparent displays requiring high switching and driving performance. In this study, we demonstrate an optimized process to secure excellent device performance with a favorable shift of the threshold voltage toward 0V in amorphous hafnium-indium-zinc-oxide (a-HfIZO) TFTs by using post-treatment with oxygen annealing. This enhancement results from the improved interfacial characteristics between gate dielectric and semiconductor layers due to the reduction in the density of interfacial states related to oxygen vacancies afforded by oxygen annealing. The device statistics confirm the improvement in the device-to-device and run-to-run uniformity. We also report on the photo-induced stability in such oxide-TFTs against long-term UV irradiation, which is significant for transparent displays.

  6. Restorative effect of oxygen annealing on device performance in HfIZO thin-film transistors

    SciTech Connect

    Ha, Tae-Jun

    2015-03-15

    Metal-oxide based thin-film transistors (oxide-TFTs) are very promising for use in next generation electronics such as transparent displays requiring high switching and driving performance. In this study, we demonstrate an optimized process to secure excellent device performance with a favorable shift of the threshold voltage toward 0V in amorphous hafnium-indium-zinc-oxide (a-HfIZO) TFTs by using post-treatment with oxygen annealing. This enhancement results from the improved interfacial characteristics between gate dielectric and semiconductor layers due to the reduction in the density of interfacial states related to oxygen vacancies afforded by oxygen annealing. The device statistics confirm the improvement in the device-to-device and run-to-run uniformity. We also report on the photo-induced stability in such oxide-TFTs against long-term UV irradiation, which is significant for transparent displays.

  7. Investigation of Factors Affecting Aerodynamic Performance of Nebulized Nanoemulsion

    PubMed Central

    Kamali, Hosein; Abbasi, Shayan; Amini, Mohammad Ali; Amani, Amir

    2016-01-01

    This work aimed to prepare a nanoemulsion preparation containing budesonide and assess its aerodynamic behavior in comparison with suspension of budesonide. In-vitro aerodynamic performance of the corresponding micellar solution (ie. nanoemulsion preparation without oil) was investigated too. Nanoemulsions of almond oil containing budesonide, as a hydrophobic model drug molecule, were prepared and optimized. Then, the effect of variation of surfactant/co-surfactant concentration on the aerodynamic properties of the nebulized aerosol was studied. The results indicated that the most physically stable formulation makes the smallest aerodynamic size. The concentration of co-surfactant was also shown to be critical in determination of aerodynamic size. Furthermore, the optimized sample, with 3% w/w almond oil, 20% w/w Tween 80+Span 80 and 2% w/w ethanol showed a smaller MMAD in comparison with the commercially available suspension and the micellar solution. PMID:28243265

  8. Prepartum nutritional strategy affects reproductive performance in dairy cows.

    PubMed

    Cardoso, F C; LeBlanc, S J; Murphy, M R; Drackley, J K

    2013-09-01

    Negative energy balance during early postpartum is associated with reduced reproductive performance in dairy cows. A pooled statistical analysis of 7 studies completed in our group from 1993 to 2010 was conducted to investigate the association between prepartum energy feeding regimen and reproductive performance. The interval from calving to pregnancy (days to pregnancy, DTP) was the dependent variable to assess reproductive performance. Individual data for 408 cows (354 multiparous and 54 primiparous) were included in the analysis. The net energy for lactation (NEL) intake was determined from each cow's average dry matter intake and calculated dietary NEL density. Treatments applied prepartum were classified as either controlled-energy (CE; limited NEL intake to ≤100% of requirement) or high-energy (HE; cows were allowed to consume >100%) diets fed during the far-off (FO) or close-up (CU) dry periods. Cow was the experimental unit. The Cox proportional hazard model revealed that days to pregnancy was shorter for CE (median=157 d) than HE (median=167 d) diets during the CU period [hazard ratio (HR)=0.70]. Cows fed HE diets during the last 4 wk prepartum lost more body condition score in the first 6 wk postpartum than those fed CE diets (-0.43 and -0.30, respectively). Cows fed CE diets during the FO period had lower nonesterified fatty acids concentrations in wk 1, 2, and 3 of lactation than cows fed HE diets. Higher nonesterified fatty acids concentration in wk 1 postpartum was associated with a greater probability of disease (n=251; odds ratio=1.18). Cows on the CE regimen during the FO period had greater plasma glucose concentrations during wk 1 and 3 after calving than cows fed the HE regimen. Higher plasma glucose (HG) concentration compared with lower glucose (LG) in wk 3 (HG: n=154; LG: n=206) and wk 4 (HG: n=71; LG: n=254) after calving was associated with shorter days to pregnancy (wk 3: median=151 and 171 d for HG and LG, respectively, and HR=1.3; wk 4

  9. Factors affecting the performance of large-aperture microphone arrays.

    PubMed

    Silverman, Harvey F; Patterson, William R; Sachar, Joshua

    2002-05-01

    Large arrays of microphones have been proposed and studied as a possible means of acquiring data in offices, conference rooms, and auditoria without requiring close-talking microphones. When such an array essentially surrounds all possible sources, it is said to have a large aperture. Large-aperture arrays have attractive properties of spatial resolution and signal-to-noise enhancement. This paper presents a careful comparison of theoretical and measured performance for an array of 256 microphones using simple delay-and-sum beamforming. This is the largest currently functional, all digital-signal-processing array that we know of. The array is wall-mounted in the moderately adverse environment of a general-purpose laboratory (8 m x 8 m x 3 m). The room has a T60 reverberation time of 550 ms. Reverberation effects in this room severely impact the array's performance. However, the width of the main lobe remains comparable to that of a simplified prediction. Broadband spatial resolution shows a single central peak with 10 dB gain about 0.4 m in diameter at the -3 dB level. Away from that peak, the response is approximately flat over most of the room. Optimal weighting for signal-to-noise enhancement degrades the spatial resolution minimally. Experimentally, we verify that signal-to-noise gain is less than proportional to the square root of the number of microphones probably due to the partial correlation of the noise between channels, to variation of signal intensity with polar angle about the source, and to imperfect correlation of the signal over the array caused by reverberations. We show measurements of the relative importance of each effect in our environment.

  10. Factors affecting the performance of large-aperture microphone arrays

    NASA Astrophysics Data System (ADS)

    Silverman, Harvey F.; Patterson, William R.; Sachar, Joshua

    2002-05-01

    Large arrays of microphones have been proposed and studied as a possible means of acquiring data in offices, conference rooms, and auditoria without requiring close-talking microphones. When such an array essentially surrounds all possible sources, it is said to have a large aperture. Large-aperture arrays have attractive properties of spatial resolution and signal-to-noise enhancement. This paper presents a careful comparison of theoretical and measured performance for an array of 256 microphones using simple delay-and-sum beamforming. This is the largest currently functional, all digital-signal-processing array that we know of. The array is wall-mounted in the moderately adverse environment of a general-purpose laboratory (8 m×8 m×3 m). The room has a T60 reverberation time of 550 ms. Reverberation effects in this room severely impact the array's performance. However, the width of the main lobe remains comparable to that of a simplified prediction. Broadband spatial resolution shows a single central peak with 10 dB gain about 0.4 m in diameter at the -3 dB level. Away from that peak, the response is approximately flat over most of the room. Optimal weighting for signal-to-noise enhancement degrades the spatial resolution minimally. Experimentally, we verify that signal-to-noise gain is less than proportional to the square root of the number of microphones probably due to the partial correlation of the noise between channels, to variation of signal intensity with polar angle about the source, and to imperfect correlation of the signal over the array caused by reverberations. We show measurements of the relative importance of each effect in our environment.

  11. New high-performance complementary bipolar technology featuring 45-GHz NPN and 20-GHz PNP devices

    NASA Astrophysics Data System (ADS)

    Wilson, Martin C.; Osborne, Peter H.; Thomas, Simon; Cook, Trevor

    1999-09-01

    A new high performance silicon complementary bipolar technology is introduced. In addition a novel process 'enhancement' technique based on a local oxidation is described and demonstrated and NPN devices with cut-off frequencies up to 45GHz and PNP devices of 20GHz have been fabricate. We propose that the technique we have used will allow specific transistors within a circuit to be optimized, as required.

  12. An amorphous mesophase generated by thermal annealing for high-performance organic photovoltaic devices.

    PubMed

    Tanaka, Hideyuki; Abe, Yoko; Matsuo, Yutaka; Kawai, Junya; Soga, Iwao; Sato, Yoshiharu; Nakamura, Eiichi

    2012-07-10

    Thermal annealing of a p-i-n organic photovoltaic device containing a crystalline benzoporphyrin donor and solvated crystals of a silylmethylfullerene acceptor increases the device performance at a temperature where partial desolvation of the acceptor produces an amorphous mesophase. This suggests that the mesophase improves the hierarchical ordering of the materials, that is, the morphology of the n-layer and the interfacial contact and, hence, the carrier generation efficiency at the donor-acceptor interface.

  13. Noise Affects Performance on the Montreal Cognitive Assessment.

    PubMed

    Dupuis, Kate; Marchuk, Veronica; Pichora-Fuller, M Kathleen

    2016-09-01

    We investigated the effect of background noise on performance on the Montreal Cognitive Assessment (MoCA). Two groups of older adults (one with clinically normal hearing, one with hearing loss) and a younger adult group with clinically normal hearing were administered two versions of the MoCA under headphones in low and high levels of background noise. Intensity levels used to present the test were customized based on the hearing abilities of participants with hearing loss to yield a uniform level of difficulty across listeners in the high-level noise condition. Both older groups had poorer MoCA scores in noise than the younger group. Importantly, all participants had poorer MoCA scores in the high-noise (M = 22.7/30) compared to the low-noise condition (M = 25.7/30, p < .001). Results suggest that background noise in the test environment should be considered when cognitive tests are conducted and results interpreted, especially when testing older adults.

  14. How neighbor canopy architecture affects target plant performance

    SciTech Connect

    Tremmel, D.C.; Bazzaz, F.A. )

    1993-10-01

    Plant competition occurs through the negative effects that individual plants have on resource availability to neighboring individuals. Therefore competition experiments need to examine how different species change resource availability to their neighbors, and how different species respond to these changes-allocationally, architecturally, and physiologically-through time. In a greenhouse study we used a model system of annuals to examine how canopies of species having differing morphologies differed in their architectures and light-interception abilities, and how different species performed when grown in these canopies. Abutilon theophrasti, Datura stramonium, and Polygonum pensylvanicum were grown as [open quotes]targets[close quotes]. Plants were grown in pots, with one target plant and four neighbor plants. Detailed measurements of neighbor canopy structure and target plant canopy architecture were made at five harvests. Species with different morphologies showed large differences in canopy structure, particularly when grass and forb species were compared. Setaria, a grass, had a more open canopy than the other species (all forbs), and was a consistently weak competitor. Overall, however, the relative effects of different neighbors on target biomass varied with target species. Target biomass was poorly correlated with neighbor biomass and leaf area, but was highly correlated with a measure of target light-interception ability that took into account both target leaf deployment and neighbor light interception. Despite clear differences among neighbor species in canopy structure and effect on light penetration, the results suggest no broad generalizations about the effects of different species as neighbors. Knowledge of morphological, physiological, and life history characteristics of both the target and neighbor species may be necessary to explain the results of their competition. 53 refs., 4 figs., 4 tabs.

  15. Aging affects spatial reconstruction more than spatial pattern separation performance even after extended practice.

    PubMed

    Clark, Rachel; Tahan, Asli C; Watson, Patrick D; Severson, Joan; Cohen, Neal J; Voss, Michelle

    2017-03-21

    Although the hippocampus experiences age-related anatomical and functional deterioration, the effects of aging vary across hippocampal-dependent cognitive processes. In particular, whether or not the hippocampus is known to be required for a spatial memory process is not an accurate predictor on its own of whether aging will affect performance. Therefore, the primary objective of this study was to compare the effects of healthy aging on a test of spatial pattern separation and a test of spatial relational processing, which are two aspects of spatial memory that uniquely emphasize the use of multiple hippocampal-dependent processes. Spatial pattern separation supports spatial memory by preserving unique representations for distinct locations. Spatial relational processing forms relational representations of objects to locations or between objects and other objects in space. To test our primary objective, 30 young (18-30 years; 21F) and 30 older participants (60-80 years; 21F) all completed a spatial pattern separation task and a task designed to require spatial relational processing through spatial reconstruction. To ensure aging effects were not due to inadequate time to develop optimal strategies or become comfortable with the testing devices, a subset of participants had extended practice across three sessions on each task. Results showed that older adults performed more poorly than young on the spatial reconstruction task that emphasized the use of spatial relational processing, and that age effects persisted even after controlling for pattern separation performance. Further, older adults performed more poorly on spatial reconstruction than young adults even after three testing sessions each separated by 7-10 days, suggesting effects of aging are resistant to extended practice and likely reflect genuine decline in hippocampal memory abilities.

  16. Simulation of temperature-dependent material parameters and device performances for GaInAsSb thermophotovoltaic cell

    NASA Astrophysics Data System (ADS)

    Peng, Xincun; Zhang, Baolin; Li, Guoxing; Zou, Jijun; Zhu, Zhifu; Cai, Zhimin; Zhou, Shumin; Li, Yuezhong; Wang, Zhicheng; Jiang, Wei

    2011-11-01

    Temperature-dependent material parameters and device performances of Ga xIn 1-xAs 1-ySb y TPV cells applied in low temperature (800-1200 °C) radiators are simulated using the PC-1D. As is well known, the optimum bandgap ( E g) decreases towards lower radiator temperatures. So far, the lowest achievable E g of Ga xIn 1-xAs 1-ySb y at 300 K is 0.5 eV. We mainly considering the Ga 0.8In 0.2As 0.18Sb 0.82 ( E g = 0.5 eV) TPV cell. The effects of doping concentration and recombination mechanisms of the emitter layer on photovoltaic conversion efficiencies ( η cel) are analyzed in detail, and η cel can be improved by optimizing doping concentration and suppressing carrier recombination. The effects of GaSb window layer on η cel are also presented. It shows the type-II energy-band alignment GaSb(window)/GaInAsSb(emitter) heterostructure affect η cel mainly through V oc. For the first time, the effects of operating temperatures on device performances are analyzed based on temperature-dependent material parameters, and the temperature coefficients of the device performances are presented.

  17. Aerodynamic Design Criteria for Class 8 Heavy Vehicles Trailer Base Devices to Attain Optimum Performance

    SciTech Connect

    Salari, K; Ortega, J

    2010-12-13

    Lawrence Livermore National Laboratory (LLNL) as part of its Department of Energy (DOE), Energy Efficiency and Renewable Energy (EERE), and Vehicle Technologies Program (VTP) effort has investigated class 8 tractor-trailer aerodynamics for many years. This effort has identified many drag producing flow structures around the heavy vehicles and also has designed and tested many new active and passive drag reduction techniques and concepts for significant on the road fuel economy improvements. As part of this effort a database of experimental, computational, and conceptual design for aerodynamic drag reduction devices has been established. The objective of this report is to provide design guidance for trailer base devices to improve their aerodynamic performance. These devices are commonly referred to as boattails, base flaps, tail devices, and etc. The information provided here is based on past research and our most recent full-scale experimental investigations in collaboration with Navistar Inc. Additional supporting data from LLNL/Navistar wind tunnel, track test, and on the road test will be published soon. The trailer base devices can be identified by 4 flat panels that are attached to the rear edges of the trailer base to form a closed cavity. These devices have been engineered in many different forms such as, inflatable and non-inflatable, 3 and 4-sided, closed and open cavity, and etc. The following is an in-depth discussion with some recommendations, based on existing data and current research activities, of changes that could be made to these devices to improve their aerodynamic performance. There are 6 primary factors that could influence the aerodynamic performance of trailer base devices: (1) Deflection angle; (2) Boattail length; (3) Sealing of edges and corners; (4) 3 versus 4-sided, Position of the 4th plate; (5) Boattail vertical extension, Skirt - boattail transition; and (6) Closed versus open cavity.

  18. Affective Responses to an Aerobic Dance Class: The Impact of Perceived Performance.

    ERIC Educational Resources Information Center

    Bartholomew, John B.; Miller, Bridget M.

    2002-01-01

    Tested the mastery hypothesis as an explanation for the affective benefits of acute exercise. Undergraduate women from a self-selected aerobic dance class rated their exercise performance following class. Affect questionnaires were completed before and at 5 and 20 minutes after the class. Results showed an overall improvement in affect following…

  19. Development of Substrate Structure CdTe Photovoltaic Devices with Performance Exceeding 10%: Preprint

    SciTech Connect

    Dhere, R. G.; Duenow, J. N.; DeHart, C. M.; Li, J. V.; Kuciauskas, D.; Gessert, T. A.

    2012-08-01

    Most work on CdTe-based solar cells has focused on devices with a superstrate structure. This focus is due to the early success of the superstrate structure in producing high-efficiency cells, problems of suitable ohmic contacts for lightly doped CdTe, and the simplicity of the structure for manufacturing. The development of the CdCl2 heat treatment boosted CdTe technology and perpetuated the use of the superstrate structure. However, despite the beneficial attributes of the superstrate structure, devices with a substrate structure are attractive both commercially and scientifically. The substrate structure eliminates the need for transparent superstrates and thus allows the use of flexible metal and possibly plastic substrates. From a scientific perspective, it allows better control in forming the junction and direct access to the junction for detailed analysis. Research on such devices has been limited. The efficiency of these devices has been limited to around 8% due to low open-circuit voltage (Voc) and fill factor. In this paper, we present our recent device development efforts at NREL on substrate-structure CdTe devices. We have found that processing parameters required to fabricate high-efficiency substrate CdTe PV devices differ from those necessary for traditional superstrate CdTe devices. We have worked on a variety of contact materials including Cu-doped ZnTe and CuxTe. We will present a comparative analysis of the performance of these contacts. In addition, we have studied the influence of fabrication parameters on junction properties. We will present an overview of our development work, which has led to CdTe devices with Voc values of more than 860 mV and NREL-confirmed efficiencies approaching 11%.

  20. Poly(vinyl alcohol)-coated microfluidic devices for high-performance microchip electrophoresis.

    PubMed

    Belder, Detlev; Deege, Alfred; Kohler, Frank; Ludwig, Martin

    2002-10-01

    The channels of microfluidic glass chips have been coated with poly(vinyl alcohol) (PVA). Applied for microchip electrophoresis, the coated devices exhibited a suppressed electroosmotic flow and improved separation performance. The superior performance of PVA-coated channels could be demonstrated by electrophoretic separations of labeled amines and by video microscopy. While a distorted sample zone is injected using uncoated channels the application of PVA-coated channels results in an improved shape of the sample zone with less band broadening. Applying PVA-coated microchips for the separation of amines labeled with Alexa Fluor 350 even sub-second separations, utilizing a separation length of only 650 microm, could be obtained, while this was not possible using uncoated devices. By using PVA-coated devices rather than an uncoated chip a threefold increase in separation efficiencies could be observed. As the electroosmotic flow (EOF) was suppressed, the anionic compounds were detected at the anode whereas the dominant EOF in uncoated devices resulted in an effective mobility to the cathode. Besides improved separation performance another important feature of the PVA-coated channels was the suppressed adsorption of fluorescent compounds in repetitive runs which results in an improved robustness and detection sensitivity. Applying PVA-coated channels, rinsing or etching steps could be omitted while this was necessary for a reliable operation of uncoated devices.

  1. Students' Achievement Goals, Emotion Perception Ability and Affect and Performance in the Classroom: A Multilevel Examination

    ERIC Educational Resources Information Center

    Vassiou, Aikaterini; Mouratidis, Athanasios; Andreou, Eleni; Kafetsios, Konstantinos

    2016-01-01

    Performance at school is affected not only by students' achievement goals but also by emotional exchanges among classmates and their teacher. In this study, we investigated relationships between students' achievement goals and emotion perception ability and class affect and performance. Participants were 949 Greek adolescent students in 49 classes…

  2. 40 CFR Table 3 to Subpart Nnnnn of... - Performance Test Requirements for HCl Production Affected Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 14 2011-07-01 2011-07-01 false Performance Test Requirements for HCl... Requirements for HCl Production Affected Sources As stated in § 63.9020, you must comply with the following requirements for performance tests for HCl production for each affected source. For each HCl process vent...

  3. Effect of Back Contact and Rapid Thermal Processing Conditions on Flexible CdTe Device Performance

    SciTech Connect

    Mahabaduge, Hasitha; Meysing, D. M.; Rance, Will L.; Burst, James M.; Reese, Matthew O.; Wolden, C. A.; Gessert, Timothy A.; Metzger, Wyatt K.; Garner, S.; Barnes, Teresa M.

    2015-06-14

    Flexible CdTe solar cells on ultra-thin glass substrates can enable new applications that require high specific power, unique form-factors, and low manufacturing costs. To be successful, these cells must be cost competitive, have high efficiency, and have high reliability. Here we present back contact processing conditions that enabled us to achieve over 16% efficiency on flexible Corning (R) Willow (R) Glass substrates. We used co-evaporated ZnTe:Cu and Au as our back contact and used rapid thermal processing (RTP) to activate the back contact. Both the ZnTe to Cu ratio and the RTP activation temperature provide independent control over the device performance. We have investigated the influence of various RTP conditions to Cu activation and distribution. Current density-voltage, capacitance-voltage measurements along with device simulations were used to examine the device performance in terms of ZnTe to Cu ratio and rapid thermal activation temperature.

  4. Impact of continuing scaling on the device performance of 3D cylindrical junction-less charge trapping memory

    NASA Astrophysics Data System (ADS)

    Xinkai, Li; Zongliang, Huo; Lei, Jin; Dandan, Jiang; Peizhen, Hong; Qiang, Xu; Zhaoyun, Tang; Chunlong, Li; Tianchun, Ye

    2015-09-01

    This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as program/erase speed, vertical charge loss, and lateral charge migration under high temperature are intensively studied using the Sentaurus 3D device simulator. Although scaling of channel radius is beneficial for operation speed improvement, it leads to a retention challenge due to vertical leakage, especially enhanced charge loss through TPO. Scaling of gate length not only decreases the program/erase speed but also leads to worse lateral charge migration. Scaling of spacer length is critical for the interference of adjacent cells and should be carefully optimized according to specific cell operation conditions. The gate stack shape is also found to be an important factor affecting the lateral charge migration. Our results provide guidance for high density and high reliability 3D CTM integration. Project supported by the National Natural Science Foundation of China (Nos. 61474137, 61176073, 61306107).

  5. Identifying Affective Domains That Correlate and Predict Mathematics Performance in High-Performing Students in Singapore

    ERIC Educational Resources Information Center

    Lim, Siew Yee; Chapman, Elaine

    2015-01-01

    Past studies have shown that distinct yet highly correlated sub-constructs of three broad mathematics affective variables: (a) motivation, (b) attitudes and (c) anxiety, have varying degree of correlation with mathematics achievement. The sub-constructs of these three affective constructs are as follows: (a) (i) amotivation, (ii) external…

  6. Performance Improvement of Total Ionization Dose Radiation Sensor Devices Using Fluorine-Treated MOHOS

    PubMed Central

    Hsieh, Wen-Ching; Lee, Hao-Tien Daniel; Jong, Fuh-Cheng; Wu, Shich-Chuan

    2016-01-01

    Fluorine-treated titanium nitride–silicon oxide–hafnium oxide–silicon oxide–silicon devices (hereafter F-MOHOS) are candidates for total ionization dose (TID) radiation sensor applications. The main subject of the study reportedherein is the performance improvement in terms of TID radiation-induced charge generation effect and charge-retention reliability characterization for F-MOHOS devices. In the case of F-MOHOS TID radiation sensors, the gamma radiation induces a significant decrease of threshold voltage VT and the radiation-induced charge density is nearly six times larger than that of standard metal–oxide–nitride–oxide–silicon MONOS devices. The decrease of VT for F-MOHOS after gamma irradiation has a strong correlation to the TID up to 5 Mrad gamma irradiation as well. The improvement of charge retention loss for F-MOHOS devices is nearly 15% better than that of metal–oxide–hafnium oxide–oxide–silicon MOHOS devices. The F-MOHOS device described in this study demonstrates better feasibility for non-volatile TID radiation sensing in the future. PMID:27043560

  7. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Fu, Y. Q.; Chen, J. J.; Xuan, W. P.; Chen, J. K.; Wang, X. Z.; Mayrhofer, P.; Duan, P. F.; Bittner, A.; Schmid, U.; Luo, J. K.

    2016-07-01

    This paper reports the characterization of scandium aluminum nitride (Al1-x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (<0.5%). The performance of the two types of devices was also investigated and compared, using acoustofluidics as an example. The AlScN/Si SAW devices achieved much lower threshold powers for the acoustic streaming and pumping of liquid droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young’s modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices.

  8. Introduction: feature issue on phantoms for the performance evaluation and validation of optical medical imaging devices.

    PubMed

    Hwang, Jeeseong; Ramella-Roman, Jessica C; Nordstrom, Robert

    2012-06-01

    The editors introduce the Biomedical Optics Express feature issue on "Phantoms for the Performance Evaluation and Validation of Optical Medical Imaging Devices." This topic was the focus of a technical workshop that was held on November 7-8, 2011, in Washington, D.C. The feature issue includes 13 contributions from workshop attendees.

  9. High Performance Graphene Nano-ribbon Thermoelectric Devices by Incorporation and Dimensional Tuning of Nanopores

    PubMed Central

    Sharafat Hossain, Md; Al-Dirini, Feras; Hossain, Faruque M.; Skafidas, Efstratios

    2015-01-01

    Thermoelectric properties of Graphene nano-ribbons (GNRs) with nanopores (NPs) are explored for a range of pore dimensions in order to achieve a high performance two-dimensional nano-scale thermoelectric device. We reduce thermal conductivity of GNRs by introducing pores in them in order to enhance their thermoelectric performance. The electrical properties (Seebeck coefficient and conductivity) of the device usually degrade with pore inclusion; however, we tune the pore to its optimal dimension in order to minimize this degradation, enhancing the overall thermoelectric performance (high ZT value) of our device. We observe that the side channel width plays an important role to achieve optimal performance while the effect of pore length is less pronounced. This result is consistent with the fact that electronic conduction in GNRs is dominated along its edges. Ballistic transport regime is assumed and a semi-empirical method using Huckel basis set is used to obtain the electrical properties, while the phononic system is characterized by Tersoff empirical potential model. The proposed device structure has potential applications as a nanoscale local cooler and as a thermoelectric power generator. PMID:26083450

  10. Visual performance with changes in eccentricity in PROSE device: a case report.

    PubMed

    Jagadeesh, Divya; Mahadevan, Rajeswari

    2014-01-01

    This case report describes the variations in visual performance of a subject with moderate keratoconus with changes in front surface eccentricities (FSEs) of PROSE (Prosthetic Replacement of Ocular Surface Ecosystem). PROSE device of 0.6 FSE provided maximum visual improvement and reduction in Higher Order Aberrations (HOAs) compared to 0, 0.3 and 0.8 FSEs in this clinical condition.

  11. Performance and Challenges of Point of Use Devices for Lead Removal

    EPA Science Inventory

    this presentation summarizes the performance of POU devices for the removal of lead and some other metals, in Flint, Michigan. The mechanism of POU filters for metal removal is described as being a combination of physical filtration with surface sorption and adherence to embedde...

  12. Combined effects of positive and negative affectivity and job satisfaction on job performance and turnover intentions.

    PubMed

    Bouckenooghe, Dave; Raja, Usman; Butt, Arif Nazir

    2013-01-01

    Capturing data from employee-supervisor dyads (N = 321) from eight organizations in Pakistan, including human service organizations, an electronics assembly plant, a packaging material manufacturing company, and a small food processing plant, we used moderated regression analysis to examine whether the relationships between trait affect (positive affectivity [PA] and negative affectivity [NA]) and two key work outcome variables (job performance and turnover) are contingent upon the level of job satisfaction. We applied the Trait Activation Theory to explain the moderating effect of job satisfaction on the relationship between affect and performance and between affect and turnover. Overall, the data supported our hypotheses. Positive and negative affectivity influenced performance and the intention to quit, and job satisfaction moderated these relationships. We discuss in detail the results of these findings and their implications for research and practice.

  13. Tuning the Performance of Organic Spintronic Devices Using X-Ray Generated Traps

    NASA Astrophysics Data System (ADS)

    Rybicki, J.; Lin, R.; Wang, F.; Wohlgenannt, M.; He, C.; Sanders, T.; Suzuki, Y.

    2012-08-01

    X rays produced during electron-beam deposition of metallic electrodes drastically change the performance of organic spintronic devices. The x rays generate traps with an activation energy of ≈0.5eV in a commonly used organic. These traps lead to a dramatic decrease in spin-diffusion length in organic spin valves. In organic magnetoresistive (OMAR) devices, however, the traps strongly enhance magnetoresistance. OMAR is an intrinsic magnetotransport phenomenon and does not rely on spin injection. We discuss our observations in the framework of currently existing theories.

  14. Electric-field enhanced performance in catalysis and solid-state devices involving gases

    DOEpatents

    Blackburn, Bryan M.; Wachsman, Eric D.; Van Assche, IV, Frederick Martin

    2015-05-19

    Electrode configurations for electric-field enhanced performance in catalysis and solid-state devices involving gases are provided. According to an embodiment, electric-field electrodes can be incorporated in devices such as gas sensors and fuel cells to shape an electric field provided with respect to sensing electrodes for the gas sensors and surfaces of the fuel cells. The shaped electric fields can alter surface dynamics, system thermodynamics, reaction kinetics, and adsorption/desorption processes. In one embodiment, ring-shaped electric-field electrodes can be provided around sensing electrodes of a planar gas sensor.

  15. Control performance of paper-based blood analysis devices through paper structure design.

    PubMed

    Li, Lizi; Huang, Xiaolei; Liu, Wen; Shen, Wei

    2014-12-10

    In this work, we investigated the influence of paper structure on the performance of paper-based analytical devices that are used for blood analysis. The question that we aimed to answer is how the fiber type (i.e., softwood and hardwood fibers) influences the fiber network structure of the paper, which affects the transport of red blood cells (RBCs) in paper. In the experimental design, we isolated the influence of fiber types on the paper structure from all other possible influencing factors by removing the fines from the pulps and not using any additives. Mercury porosimetry was employed to characterize the pore structures of the paper sheets. The results show that papers with a low basis weight that are made with short hardwood fibers have a higher porosity (i.e., void fraction) and simpler pore structures compared with papers made with long softwood fibers. RBC transport in paper carried by saline solution was investigated in two modes: lateral chromatographic elution and vertical flow-through. The results showed that the complexity of the paper's internal pore structure has a dominant influence on the transport of RBCs in paper. Hardwood fiber sheets with a low basis weight have a simple internal pore structure and allow for the easy transport of RBCs. Blood-typing sensors built with low basis weight hardwood fibers deliver high-clarity assays. Softwood fiber papers are found to have a more complex pore structure, which makes RBC transport more difficult, leading to blood-typing results of low clarity. This study provides the principle of paper sheet design for paper-based blood analysis sensors.

  16. Photovoltaic performance of block copolymer devices is independent of the crystalline texture in the active layer

    DOE PAGES

    Guo, Changhe; Lee, Youngmin; Lin, Yen -Hao; ...

    2016-06-15

    The electronic properties of organic semiconductors are strongly influenced by intermolecular packing. When cast as thin films, crystalline π-conjugated molecules are strongly textured, potentially leading to anisotropic charge transport. Consequently, it is hypothesized that the orientation of crystallites in the active layer plays an important role in charge extraction and organic photovoltaic device performance. Here we demonstrate orientation control of molecular packing from mostly face-on to edge-on configurations in the active layer of P3HT-b-PFTBT block copolymer photovoltaics using 1-chloronaphthalene as a solvent additive. The effect of molecular orientations in P3HT crystals on charge transport and solar cell performance is examined.more » We find that optimized photovoltaic device performance is independent of the crystalline texture of P3HT. Our observations provide further insights into the molecular organization required for efficient charge transport and overall device efficiencies. That is, the dominant crystal orientation, whether face-on or edge-on, is not critical to organic solar cells. Furthermore, a broad distribution of crystallite orientations ensures pathways for charge transport in any direction and enables efficient charge extraction in photovoltaic devices.« less

  17. Photovoltaic performance of block copolymer devices is independent of the crystalline texture in the active layer

    SciTech Connect

    Guo, Changhe; Lee, Youngmin; Lin, Yen -Hao; Strzalka, Joseph; Wang, Cheng; Hexemer, Alexander; Jaye, Cherno; Fischer, Daniel A.; Verduzco, Rafael; Wang, Qing; Gomez, Enrique D.

    2016-06-15

    The electronic properties of organic semiconductors are strongly influenced by intermolecular packing. When cast as thin films, crystalline π-conjugated molecules are strongly textured, potentially leading to anisotropic charge transport. Consequently, it is hypothesized that the orientation of crystallites in the active layer plays an important role in charge extraction and organic photovoltaic device performance. Here we demonstrate orientation control of molecular packing from mostly face-on to edge-on configurations in the active layer of P3HT-b-PFTBT block copolymer photovoltaics using 1-chloronaphthalene as a solvent additive. The effect of molecular orientations in P3HT crystals on charge transport and solar cell performance is examined. We find that optimized photovoltaic device performance is independent of the crystalline texture of P3HT. Our observations provide further insights into the molecular organization required for efficient charge transport and overall device efficiencies. That is, the dominant crystal orientation, whether face-on or edge-on, is not critical to organic solar cells. Furthermore, a broad distribution of crystallite orientations ensures pathways for charge transport in any direction and enables efficient charge extraction in photovoltaic devices.

  18. Enhancing the electrical and optoelectronic performance of nanobelt devices by molecular surface functionalization.

    PubMed

    Lao, Changshi; Li, Yi; Wong, C P; Wang, Z L

    2007-05-01

    By functionalizing the surfaces of ZnO nanobelts (NBs) with a thin self-assembled molecular layer, the electrical and optoelectronic performances of a single NB-based device are drastically improved. For a single NB-based device, due to energy band tuning and surface modification, the conductance was enhanced by 6 orders of magnitude upon functionalization; a coating molecule layer has changed a Schottky contact into an Ohmic contact without sophisticated deposition of multilayered metals. A functionalized NB showed negative differential resistance and exhibited huge improved photoconductivity and gas sensing response. The functionalized molecular layer also greatly reduced the etching rate of the ZnO NBs by buffer solution, largely extending their life time for biomedical applications. Our study demonstrates a new approach for improving the physical properties of oxide NBs and nanowires for device applications.

  19. Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET

    PubMed Central

    2012-01-01

    The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency. PMID:22901374

  20. Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET

    NASA Astrophysics Data System (ADS)

    Tan, Michael Loong Peng; Lentaris, Georgios; Amaratunga AJ, Gehan

    2012-08-01

    The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio ( I on/ I off), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.

  1. Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET.

    PubMed

    Tan, Michael Loong Peng; Lentaris, Georgios; Amaratunga Aj, Gehan

    2012-08-19

    The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.

  2. Does medical students’ clinical performance affect their actual performance during medical internship?

    PubMed Central

    Han, Eui-Ryoung; Chung, Eun-Kyung

    2016-01-01

    INTRODUCTION This study examines the relationship between the clinical performance of medical students and their performance as doctors during their internships. METHODS This retrospective study involved 63 applicants of a residency programme conducted at Chonnam National University Hospital, South Korea, in November 2012. We compared the performance of the applicants during their internship with their clinical performance during their fourth year of medical school. The performance of the applicants as interns was periodically evaluated by the faculty of each department, while their clinical performance as fourth-year medical students was assessed using the Clinical Performance Examination (CPX) and the Objective Structured Clinical Examination (OSCE). RESULTS The performance of the applicants as interns was positively correlated with their clinical performance as fourth-year medical students, as measured by the CPX and OSCE. The performance of the applicants as interns was moderately correlated with the patient-physician interaction items addressing communication and interpersonal skills in the CPX. CONCLUSION The clinical performance of medical students during their fourth year in medical school was related to their performance as medical interns. Medical students should be trained to develop good clinical skills through actual encounters with patients or simulated encounters using manikins, to enable them to become more competent doctors. PMID:26768172

  3. Performance and Characterization of Magnetic Penetration Thermometer Devices for X-Ray Spectroscopy

    NASA Technical Reports Server (NTRS)

    Porst, J. -P.; Adams, J. S.; Bandler, S. R.; Balvin, M.; Busch, S. E.; Denis, K. L.; Kelly, D.; Nagler, P.; Sadleir, J. E.; Seidel, G. M.; Smith, S.; Stevenson, T. R.

    2012-01-01

    We are developing magnetic penetration thermometers (MPTs) for applications in X-ray astronomy. These non-dissipative devices consist of an X-ray absorber in good thermal contact to a superconducting thin film with a transition temperature around T=100mK. A microfabricated superconducting planar inductor underneath is used to store a persistent current and couple the superconductor's diamagnetic response to a readout SQUID. The strong temperature dependence of the diamagnetic response make these devices suitable for highly sensitive macroscopic thermometers that are capable of achieving very high energy resolution. We present results achieved with MPTs consisting of MoAu bilayer sensors attached to overhanging square 250 micron by 250 micron gold absorbers that have demonstrated an energy resolution of delta E_FWHM=2.3eV at an X-ray energy of 5.9keV. A similar device has shown delta E_FWHM=2.0eV at 1.5 keV. Under certain conditions and for specific device geometries, the temperature responsivity of the MPTs can vary on long timescales degrading the spectral performance. We present the characterization of different inductor geometries to optimize the design for the highest possible temperature sensitivity and compare different device designs with respect to responsivity stability.

  4. A paper and plastic device for performing recombinase polymerase amplification of HIV DNA.

    PubMed

    Rohrman, Brittany A; Richards-Kortum, Rebecca R

    2012-09-07

    Despite the importance of early diagnosis and treatment of HIV, only a small fraction of HIV-exposed infants in low- and middle-income countries are tested for the disease. The gold standard for early infant diagnosis, DNA PCR, requires resources that are unavailable in poor settings, and no point-of-care HIV DNA test is currently available. We have developed a device constructed of layers of paper, glass fiber, and plastic that is capable of performing isothermal, enzymatic amplification of HIV DNA. The device is inexpensive, small, light-weight, and easy to assemble. The device stores lyophilized enzymes, facilitates mixing of reaction components, and supports recombinase polymerase amplification in five steps of operation. Using commercially available lateral flow strips as a detection method, we demonstrate the ability of our device to amplify 10 copies of HIV DNA to detectable levels in 15 min. Our results suggest that our device, which is designed to be used after DNA extraction from dried-blood spots, may serve in conjunction with lateral flow strips as part of a point-of-care HIV DNA test to be used in low resource settings.

  5. Assessment of v-gel supraglottic airway device placement in cats performed by inexperienced veterinary students.

    PubMed

    Barletta, M; Kleine, S A; Quandt, J E

    2015-11-21

    Endotracheal intubation has been associated with several complications in cats. The v-gel supraglottic airway device (SGAD) has been developed to adapt to the unique oropharynx of the cat and to overcome these complications. Thirty-three cats were randomly assigned to receive an endotracheal tube (ETT group) or a v-gel SGAD (v-gel group) after induction of general anaesthesia. Third year veterinary students without previous clinical experience placed these devices under direct supervision of an anaesthesiologist. Amount of propofol, number of attempts, time required to secure the airway, leakage around the device, signs of upper airway discomfort and food consumption were compared between the two groups. The v-gel group required less propofol (P=0.03), less time (P<0.01) and fewer attempts (P<0.01) to secure the cats' airway. The incidence of leakage was lower for the v-gel group immediately after placement of the device (P<0.01) and 60 minutes after induction of general anaesthesia (P=0.04). Cats that received the v-gel SGAD presented a lower incidence of upper airway discomfort immediately after the device was removed (P=0.03) and recorded a higher food consumption score (P=0.03). The v-gel SGAD is a feasible way to secure the airway of healthy cats when performed by inexperienced personnel.

  6. Pediatric hydrocephalus: Does the shunt device pressure selection affect the outcome?

    PubMed Central

    Sinha, Arvind; Sharma, Anuj; Gupta, Charitesh

    2012-01-01

    Aim: To compare the efficacy of low- versus medium-pressure shunts in pediatric hydrocephalus in a randomized controlled trial. Materials and Methods: Forty patients of pediatric hydrocephalus were randomized into two groups. The Chhabra differential pressure VP shunt (low or medium) was inserted in every patient. Postoperative follow-up was performed for symptomatic improvement and radiological evaluation (by sonography or computed tomography scan) for ventricle hemispheric ratio (VHR). Comparative analysis of pre- and postoperative VHR and need of redo surgery for shunt malformation were carried out to establish outcomes. Results: Nineteen patients had a low-pressure and 21 patients had a medium-pressure shunt inserted. The age of the patients ranged from 1 day to 10 years. The average preoperative VHR in group A was 55.37%, which reduced to 40% postoperatively (P = 0.00005); likewise, the pre- and postoperative VHR in group B were 61.57% and 42%, respectively, which was statistically significant (P = 0.0006). The complications of shunts and incidence of redo shunt surgery in both groups were not found to be statistically significant (P = 0.5614). Conclusions: The study found no significant difference in the outcome of patients with low- or medium-pressure shunt placement in pediatric hydrocephalus. PMID:22529548

  7. Does the personal lift-assist device affect the local dynamic stability of the spine during lifting?

    PubMed

    Graham, Ryan B; Sadler, Erin M; Stevenson, Joan M

    2011-02-03

    The personal lift-assist device (PLAD) is an on-body ergonomic aid that reduces low back physical demands through the restorative moment of an external spring element, which possesses a mechanical advantage over the erector spinae. Although the PLAD has proven effective at reducing low back muscular demand, spinal moments, and localized muscular fatigue during laboratory and industrial tasks, the effects of the device on the neuromuscular control of spinal stability during lifting have yet to be assessed. Thirty healthy subjects (15M, 15F) performed repetitive lifting for three minutes, at a rate of 10 lifts per minute, with and without the PLAD. Maximum finite-time Lyapunov exponents, representing short-term (λ(max-s)) and long-term (λ(max-l)) divergence were calculated from the measured trunk kinematics to estimate the local dynamic stability of the lumbar spine. Using a mixed-design repeated-measures ANOVA, it was determined that wearing the PLAD did not significantly change λ(max-s) (μ(NP)=0.335, μ(P)=0.321, p=0.225), but did significantly reduce λ(max-l) (μ(NP)=0.0024, μ(P)=-0.0011, p=0.014, η(2)=0.197). There were no between-subject effects of sex, or significant interactions (p>0.720). The present results indicated that λ(max-s) was not statistically different between the device conditions, but that the PLAD significantly reduced λ(max-l) to a negative (stable) value. This shows that subjects' neuromuscular systems were able to respond to local perturbations more effectively when wearing the device, reflecting a more stable control of spinal movements. These findings are important when recommending the PLAD for long-term industrial or clinical use.

  8. Performance analysis of resistive switching devices based on BaTiO3 thin films

    NASA Astrophysics Data System (ADS)

    Samardzic, Natasa; Kojic, Tijana; Vukmirovic, Jelena; Tripkovic, Djordjije; Bajac, Branimir; Srdic, Vladimir; Stojanovic, Goran

    2016-03-01

    Resitive switching devices, memristors, have recenty attracted much attention due to promising performances and potential applications in the field of logic and memory devices. Here, we present thin film BaTiO3 based memristor fabricated using ink-jet printing technique. Active material is a single layer barium titanate film with thickness of ̴100 nm, sandwitched between metal electodes. Printing parameters were optimized aiming to achieve stable drop flow and uniform printed layer. Current-voltage characteristics show typical memristive behavior with pinched hysteresis loop crossed at the origin, with marked differences between High Resistive State (HRS) and Low Resistive State (LRS). Obtained resistive states are stable during numerous switching processes. The device also shows unipolar switching effect for negative voltage impulses. Variable voltage impulse amplitudes leads to the shifting of the energy levels of electode contacts resulting in changing of the overall current through the device. Structural charcterization have been performed using XRD analysis and SEM micrography. High-temperature current-voltage measurements combined with transport parameter analysis using Hall efect measurement system (HMS 3000) and Impedance Analyzer AC measurements allows deeper insigth into conduction mechanism of ferroelectric memristors.

  9. Surface acoustic wave nebulization device with dual interdigitated transducers improves SAWN-MS performance.

    PubMed

    Huang, Yue; Heron, Scott R; Clark, Alicia M; Edgar, J Scott; Yoon, Sung Hwan; Kilgour, David P A; Turecek, Frantisek; Aliseda, Alberto; Goodlett, David R

    2016-06-01

    We compared mass spectrometric (MS) performance of surface acoustic wave nebulization (SAWN) generated by a single interdigitated transducer (IDT) designed to produce a progressive wave (PW) to one with a dual IDT that can in theory generate standing waves (SW). Given that devices using dual IDTs had been shown to produce fewer large size droplets on average, we hypothesized they would improve MS performance by improving the efficiency of desolvation. Indeed, the SW-SAWN chip provided an improved limit of detection of 1 femtomole of peptide placed on chip making it 100× more sensitive than the PW design. However, as measured by high-speed image recording and phase Doppler particle analyzer measurements, there was only a 26% increase in the small diameter (1-10 µm) droplets produced from the new device, precluding a conclusion that the decrease in droplet size was solely responsible for the improvement in MS signal/noise. Given that the dual IDT design produced a more instantaneous plume than the PW design, the more likely contributor to improved MS signal/noise was concluded to be a higher ion flux entering the mass spectrometer for the dual IDT designs. Notably, the dual IDT device allowed production of much higher quality protein mass spectra up to about 20 kDa, compared with the single IDT device. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Performance of point-of-use devices to remove manganese from drinking water.

    PubMed

    Carrière, Annie; Brouillon, Manon; Sauvé, Sébastien; Bouchard, Maryse F; Barbeau, Benoit

    2011-01-01

    A recent epidemiological study reported significant cognitive deficits among children in relation with consumption of water with manganese concentrations in the order of 50-100 ug/L. Concerns for neurotoxic effects of manganese raises the need for evaluating the efficiency of domestic water treatment systems for removal of this metal. The objective of the present study was to determine whether POU devices are efficient at reducing dissolved manganese concentration in drinking water. Various devices were tested according to the NSF 53 protocol for general metals for high pH test water. Based on these assays, the pour-through filters were identified as the most promising POU devices, with dissolved manganese removal greater than 60% at 100% rated capacity, and greater than 45% at 200% rated capacity (influent Mn ≈1,000 μg/L). Under-the-sink filters using cationic exchange resins (i.e., water softeners) were also efficient at removing dissolved manganese but over a shorter operating life. Manganese leaching was also observed beyond their rated capacity, making them less robust treatments. The activated carbon block filters and other proprietary technologies were found to be inappropriate for dissolved manganese removal. Further evaluation of POU devices performance should evaluate the impact of hardness on process performance. The impact of particulate Mn should also be evaluated.

  11. A review of performance of near-infrared fluorescence imaging devices used in clinical studies

    PubMed Central

    Zhu, B

    2015-01-01

    Near-infrared fluorescence (NIRF) molecular imaging holds great promise as a new “point-of-care” medical imaging modality that can potentially provide the sensitivity of nuclear medicine techniques, but without the radioactivity that can otherwise place limitations of usage. Recently, NIRF imaging devices of a variety of designs have emerged in the market and in investigational clinical studies using indocyanine green (ICG) as a non-targeting NIRF contrast agent to demark the blood and lymphatic vasculatures both non-invasively and intraoperatively. Approved in the USA since 1956 for intravenous administration, ICG has been more recently used off label in intradermal or subcutaneous administrations for fluorescence imaging of the lymphatic vasculature and lymph nodes. Herein, we summarize the devices of a variety of designs, summarize their performance in lymphatic imaging in a tabular format and comment on necessary efforts to develop standards for device performance to compare and use these emerging devices in future, NIRF molecular imaging studies. PMID:25410320

  12. Improvement of device performance of polymer organic light-emitting diodes on smooth transparent sheet with graphene films synthesized by plasma treatment

    NASA Astrophysics Data System (ADS)

    Okigawa, Yuki; Mizutani, Wataru; Suzuki, Kenkichi; Ishihara, Masatou; Yamada, Takatoshi; Hasegawa, Masataka

    2015-09-01

    Because graphene films have one-atom thickness, the morphology of the transparent sheets could have a greater effect on the performance of organic light-emitting diode (OLED) devices with graphene films than on that with indium tin oxide (ITO). In this study, we have evaluated the polymer OLED devices with graphene films synthesized by plasma treatment on poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) sheets having high flatness. The results imply that the surface roughness of the transparent sheets predominantly affects the luminescence of polymer OLED devices with graphene films. The suppression of leakage current and a luminescence higher than 8000 cd/m2 at 15 V were attained for the devices on the transparent sheet with higher flatness in spite of the presence of large sharp spikes.

  13. Effect of the preparation procedure on the morphology of thin TiO₂ films and their device performance in small-molecule bilayer hybrid solar cells.

    PubMed

    Unger, Eva L; Spadavecchia, Francesca; Nonomura, Kazuteru; Palmgren, Pål; Cappelletti, Giuseppe; Hagfeldt, Anders; Johansson, Erik M J; Boschloo, Gerrit

    2012-11-01

    Flat titanium dioxide films, to be used as the acceptor layer in bilayer hybrid solar cell devices, were prepared by spray-pyrolysis and by spin-casting. Both preparation methods resulted in anatase titania films with similar optical and electronic properties but considerably different film morphologies. Spray pyrolysis resulted in dense TiO₂ films grown onto and affected by the surface roughness of the underlying conducting glass substrates. The spin-casting preparation procedure resulted in nanoporous titania films. Hybrid solar cell devices with varying layer thickness of the small-molecule semiconducting dye TDCV-TPA were investigated. Devices built with spray-pyrolyzed titania substrates yielded conversion efficiencies up to 0.47%. Spin-cast titania substrates exhibited short circuits for thin dye layer thickness. For thicker dye layers the performance of these devices was up to 0.6% due to the higher interfacial area for charge separation of these nanoporous TiO₂ substrates.

  14. To branch out or stay focused? Affective shifts differentially predict organizational citizenship behavior and task performance.

    PubMed

    Yang, Liu-Qin; Simon, Lauren S; Wang, Lei; Zheng, Xiaoming

    2016-06-01

    We draw from personality systems interaction (PSI) theory (Kuhl, 2000) and regulatory focus theory (Higgins, 1997) to examine how dynamic positive and negative affective processes interact to predict both task and contextual performance. Using a twice-daily diary design over the course of a 3-week period, results from multilevel regression analysis revealed that distinct patterns of change in positive and negative affect optimally predicted contextual and task performance among a sample of 71 employees at a medium-sized technology company. Specifically, within persons, increases (upshifts) in positive affect over the course of a workday better predicted the subsequent day's organizational citizenship behavior (OCB) when such increases were coupled with decreases (downshifts) in negative affect. The optimal pattern of change in positive and negative affect differed, however, in predicting task performance. That is, upshifts in positive affect over the course of the workday better predicted the subsequent day's task performance when such upshifts were accompanied by upshifts in negative affect. The contribution of our findings to PSI theory and the broader affective and motivation regulation literatures, along with practical implications, are discussed. (PsycINFO Database Record

  15. Performance-Based Occupational Affective Behavior Analysis (OABA). Implementation and Supporting Research.

    ERIC Educational Resources Information Center

    Pucel, David J.; And Others

    This document contains two sections: implementation of the performance-based Occupational Affective Behavior Analysis (OABA), and supporting research. Section 1 presents OABA, an analytic procedure designed to identify those affective behaviors important to success in an occupation, and gives directions on how to implement the procedure. The…

  16. Investigating Learner Affective Performance in Web-Based Learning by Using Entrepreneurship as a Metaphor

    ERIC Educational Resources Information Center

    Liu, Ming-Chou; Chi, Ming-Hsiao

    2012-01-01

    In the era of the Internet, factors which influence effective learning in a Web-based learning environment are well worth exploring. In addition to knowledge acquisition and skills training, affect is also an important factor, since successful learning requires excellent affective performance. Thus this study focuses on learners' affective…

  17. Psychological Factor Affecting English Speaking Performance for the English Learners in Indonesia

    ERIC Educational Resources Information Center

    Haidara, Youssouf

    2016-01-01

    In every learning situation or environment, human psychology plays a significant role. English speaking is a language skill that is highly affected by human psychology. This research aimed at describing the psychological factor that affects negatively the English speaking performance for the English learners in Indonesia. A descriptive qualitative…

  18. Using a False Biofeedback Methodology to Explore Relationships between Learners' Affect, Metacognition, and Performance

    ERIC Educational Resources Information Center

    Strain, Amber Chauncey; Azevedo, Roger; D'Mello, Sidney K.

    2013-01-01

    We used a false-biofeedback methodology to manipulate physiological arousal in order to induce affective states that would influence learners' metacognitive judgments and learning performance. False-biofeedback is a method used to induce physiological arousal (and resultant affective states) by presenting learners with audio stimuli of false heart…

  19. Happy Places, Horrible Times, and Scary Learners: Affective Performances and Sticky Objects in Inclusive Classrooms

    ERIC Educational Resources Information Center

    Naraian, Srikala; Khoja-Moolji, Shenila

    2016-01-01

    Drawing on data from two studies conducted in US public schools, this paper traces the affective productions and performances of teachers to illustrate the role of affect in delineating (non)normative pedagogical practices in inclusive classrooms. Occupying a borderland space in narrative inquiry that permitted the straddling of differing…

  20. Performing a secondary executive task with affective stimuli interferes with decision making under risk conditions.

    PubMed

    Gathmann, Bettina; Pawlikowski, Mirko; Schöler, Tobias; Brand, Matthias

    2014-05-01

    Previous studies demonstrated that executive functions are crucial for advantageous decision making under risk and that therefore decision making is disrupted when working memory capacity is demanded while working on a decision task. While some studies also showed that emotions can affect decision making under risk, it is unclear how affective processing and executive functions predict decision-making performance in interaction. The current experimental study used a between-subjects design to examine whether affective pictures (positive and negative pictures compared to neutral pictures), included in a parallel executive task (working memory 2-back task), have an impact on decision making under risk as assessed by the Game of Dice Task (GDT). Moreover, the performance GDT plus 2-back task was compared to the performance in the GDT without any additional task (GDT solely). The results show that the performance in the GDT differed between groups (positive, negative, neutral, and GDT solely). The groups with affective pictures, especially those with positive pictures in the 2-back task, showed more disadvantageous decisions in the GDT than the groups with neutral pictures and the group performing the GDT without any additional task. However, executive functions moderated the effect of the affective pictures. Regardless of affective influence, subjects with good executive functions performed advantageously in the GDT. These findings support the assumption that executive functions and emotional processing interact in predicting decision making under risk.

  1. Comparative Performance Assessment of Point-of-Care Testing Devices for Measuring Glucose and Ketones at the Patient Bedside

    PubMed Central

    Ceriotti, Ferruccio; Kaczmarek, Ewa; Guerra, Elena; Mastrantonio, Fabrizio; Lucarelli, Fausto; Valgimigli, Francesco; Mosca, Andrea

    2014-01-01

    Background: Point-of-care (POC) testing devices for monitoring glucose and ketones can play a key role in the management of dysglycemia in hospitalized diabetes patients. The accuracy of glucose devices can be influenced by biochemical changes that commonly occur in critically ill hospital patients and by the medication prescribed. Little is known about the influence of these factors on ketone POC measurements. The aim of this study was to assess the analytical performance of POC hospital whole-blood glucose and ketone meters and the extent of glucose interference factors on the design and accuracy of ketone results. Methods: StatStrip glucose/ketone, Optium FreeStyle glucose/ketone, and Accu-Chek Performa glucose were also assessed and results compared to a central laboratory reference method. The analytical evaluation was performed according to Clinical and Laboratory Standards Institute (CLSI) protocols for precision, linearity, method comparison, and interference. Results: The interferences assessed included acetoacetate, acetaminophen, ascorbic acid, galactose, maltose, uric acid, and sodium. The accuracies of both Optium ketone and glucose measurements were significantly influenced by varying levels of hematocrit and ascorbic acid. StatStrip ketone and glucose measurements were unaffected by the interferences tested with exception of ascorbic acid, which reduced the higher level ketone value. The accuracy of Accu-Chek glucose measurements was affected by hematocrit, by ascorbic acid, and significantly by galactose. The method correlation assessment indicated differences between the meters in compliance to ISO 15197 and CLSI 12-A3 performance criteria. Conclusions: Combined POC glucose/ketone methods are now available. The use of these devices in a hospital setting requires careful consideration with regard to the selection of instruments not sensitive to hematocrit variation and presence of interfering substances. PMID:25519295

  2. Comparative performance assessment of point-of-care testing devices for measuring glucose and ketones at the patient bedside.

    PubMed

    Ceriotti, Ferruccio; Kaczmarek, Ewa; Guerra, Elena; Mastrantonio, Fabrizio; Lucarelli, Fausto; Valgimigli, Francesco; Mosca, Andrea

    2015-03-01

    Point-of-care (POC) testing devices for monitoring glucose and ketones can play a key role in the management of dysglycemia in hospitalized diabetes patients. The accuracy of glucose devices can be influenced by biochemical changes that commonly occur in critically ill hospital patients and by the medication prescribed. Little is known about the influence of these factors on ketone POC measurements. The aim of this study was to assess the analytical performance of POC hospital whole-blood glucose and ketone meters and the extent of glucose interference factors on the design and accuracy of ketone results. StatStrip glucose/ketone, Optium FreeStyle glucose/ketone, and Accu-Chek Performa glucose were also assessed and results compared to a central laboratory reference method. The analytical evaluation was performed according to Clinical and Laboratory Standards Institute (CLSI) protocols for precision, linearity, method comparison, and interference. The interferences assessed included acetoacetate, acetaminophen, ascorbic acid, galactose, maltose, uric acid, and sodium. The accuracies of both Optium ketone and glucose measurements were significantly influenced by varying levels of hematocrit and ascorbic acid. StatStrip ketone and glucose measurements were unaffected by the interferences tested with exception of ascorbic acid, which reduced the higher level ketone value. The accuracy of Accu-Chek glucose measurements was affected by hematocrit, by ascorbic acid, and significantly by galactose. The method correlation assessment indicated differences between the meters in compliance to ISO 15197 and CLSI 12-A3 performance criteria. Combined POC glucose/ketone methods are now available. The use of these devices in a hospital setting requires careful consideration with regard to the selection of instruments not sensitive to hematocrit variation and presence of interfering substances.

  3. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    DOEpatents

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  4. An integrated device with high performance multi-function generators and time-to-digital convertors.

    PubMed

    Qin, X; Shi, Z; Xie, Y; Wang, L; Rong, X; Jia, W; Zhang, W; Du, J

    2017-01-01

    A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

  5. An integrated device with high performance multi-function generators and time-to-digital convertors

    NASA Astrophysics Data System (ADS)

    Qin, X.; Shi, Z.; Xie, Y.; Wang, L.; Rong, X.; Jia, W.; Zhang, W.; Du, J.

    2017-01-01

    A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

  6. Highly absorbing gadolinium test device to characterize the performance of neutron imaging detector systems

    SciTech Connect

    Gruenzweig, C.; Frei, G.; Lehmann, E.; Kuehne, G.; David, C.

    2007-05-15

    We report on the fabrication and application of a novel neutron imaging test device made of gadolinium. It is designed for a real time evaluation of the spatial resolution, resolution direction, and distortions of a neutron imaging detector system. Measurements of the spatial resolution of {sup 6}LiF doped ZnS scintillator screens with different thicknesses and of imaging plates were performed. The obtained results are in good agreement with comparison measurements using the standard knife edge detection method.

  7. Performance Measurement of a Multi-Level/Analog Ferroelectric Memory Device Design

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

    2007-01-01

    Increasing the memory density and utilizing the unique characteristics of ferroelectric devices is important in making ferroelectric memory devices more desirable to the consumer. This paper describes the characterization of a design that allows multiple levels to be stored in a ferroelectric based memory cell. It can be used to store multiple bits or analog values in a high speed nonvolatile memory. The design utilizes the hysteresis characteristic of ferroelectric transistors to store an analog value in the memory cell. The design also compensates for the decay of the polarization of the ferroelectric material over time. This is done by utilizing a pair of ferroelectric transistors to store the data. One transistor is used a reference to determinethe amount of decay that has occurred since the pair was programmed. The second transistor stores the analog value as a polarization value between zero and saturated. The design allows digital data to be stored as multiple bits in each memory cell. The number of bits per cell that can be stored will vary with the decay rate of the ferroelectric transistors and the repeatability of polarization between transistors. This paper presents measurements of an actual prototype memory cell. This prototype is not a complete implementation of a device, but instead, a prototype of the storage and retrieval portion of an actual device. The performance of this prototype is presented with the projected performance of the overall device. This memory design will be useful because it allows higher memory density, compensates for the environmental and ferroelectric aging processes, allows analog values to be directly stored in memory, compensates for the thermal and radiation environments associated with space operations, and relies only on existing technologies.

  8. Dosimetric and bremsstrahlung performance of a single convergent beam for teletherapy device.

    PubMed

    Figueroa, R G; Santibáñez, M; Valente, M

    2016-12-01

    The present work investigates preliminary feasibility and characteristics of a new type of radiation therapy modality based on a single convergent beam of photons. The proposal consists of the design of a device capable of generating convergent X-ray beams useful for radiotherapy. The main goal is to achieve high concentrated dose delivery. The first step is an analytical approach in order to characterize the dosimetric performance of the hypothetical convergent photon beam. Then, the validated FLUKA Monte Carlo main code is used to perform complete radiation transport to account also for scattering effects. The proposed method for producing convergent X-rays is mainly based on the bremsstrahlung effect. Hence the operating principle of the proposed device is described in terms of bremsstrahlung production. The work is mainly devoted characterizing the effect on the bremsstrahlung yield due to accessories present in the device, like anode material and geometry, filtration and collimation systems among others. The results obtained for in-depth dose distributions, by means of analytical and stochastic approaches, confirm the presence of a high dose concentration around the irradiated target, as expected. Moreover, it is shown how this spot of high dose concentration depends upon the relevant physical properties of the produced convergent photon beam. In summary, the proposed design for producing single convergent X-rays attained satisfactory performance for achieving high dose concentration around small targets depending on beam spot size that may be used for some applications in radiotherapy, like radiosurgery.

  9. Effect of Mesostructured Layer upon Crystalline Properties and Device Performance on Perovskite Solar Cells.

    PubMed

    Listorti, Andrea; Juarez-Perez, Emilio J; Frontera, Carlos; Roiati, Vittoria; Garcia-Andrade, Laura; Colella, Silvia; Rizzo, Aurora; Ortiz, Pablo; Mora-Sero, Ivan

    2015-05-07

    One of the most fascinating characteristics of perovskite solar cells (PSCs) is the retrieved obtainment of outstanding photovoltaic (PV) performances withstanding important device configuration variations. Here we have analyzed CH3NH3PbI3-xClx in planar or in mesostructured (MS) configurations, employing both titania and alumina scaffolds, fully infiltrated with perovskite material or presenting an overstanding layer. The use of the MS scaffold induces to the perovskite different structural properties, in terms of grain size, preferential orientation, and unit cell volume, in comparison to the ones of the material grown with no constraints, as we have found out by X-ray diffraction analyses. We have studied the effect of the PSC configuration on photoinduced absorption and time-resolved photoluminescence, complementary techniques that allow studying charge photogeneration and recombination. We have estimated electron diffusion length in the considered configurations observing a decrease when the material is confined in the MS scaffold with respect to a planar architecture. However, the presence of perovskite overlayer allows an overall recovering of long diffusion lengths explaining the record PV performances obtained with a device configuration bearing both the mesostructure and a perovskite overlayer. Our results suggest that performance in devices with perovskite overlayer is mainly ruled by the overlayer, whereas the mesoporous layer influences the contact properties.

  10. Developments in the design and performance of IR scene projector devices at BAE Systems

    NASA Astrophysics Data System (ADS)

    Pritchard, Alan P.; Balmond, Mark D.; Venables, Mark A.; Lake, Stephen P.

    2000-07-01

    The status of development of resistor-array infra-red scene projector devices at BAE SYSTEMS is that two variants of a 512 X 512 array have each been brought to a second development stage, whilst work on higher complexity arrays is slow but purposeful. In this paper we describe the latest features of the 512 arrays, exhibiting on the one hand high fidelity performance through a ballast-load configuration, and on the other hand very high apparent temperature output, coupled with high speed performance. For higher complexity arrays we describe some of the system philosophy and preliminary design work.

  11. Comparative study on the performance of five different Hall effect devices.

    PubMed

    Paun, Maria-Alexandra; Sallese, Jean-Michel; Kayal, Maher

    2013-02-05

    Five different Hall Effect sensors were modeled and their performance evaluated using a three dimensional simulator. The physical structure of the implemented sensors reproduces a certain technological fabrication process. Hall voltage, absolute, current-related, voltage-related and power-related sensitivities were obtained for each sensor. The effect of artificial offset was also investigated for cross-like structures. The simulation procedure guides the designer in choosing the Hall cell optimum shape, dimensions and device polarization conditions that would allow the highest performance.

  12. Best-case performance of quantum annealers on native spin-glass benchmarks: How chaos can affect success probabilities

    NASA Astrophysics Data System (ADS)

    Zhu, Zheng; Ochoa, Andrew J.; Schnabel, Stefan; Hamze, Firas; Katzgraber, Helmut G.

    2016-01-01

    Recent tests performed on the D-Wave Two quantum annealer have revealed no clear evidence of speedup over conventional silicon-based technologies. Here we present results from classical parallel-tempering Monte Carlo simulations combined with isoenergetic cluster moves of the archetypal benchmark problem—an Ising spin glass—on the native chip topology. Using realistic uncorrelated noise models for the D-Wave Two quantum annealer, we study the best-case resilience, i.e., the probability that the ground-state configuration is not affected by random fields and random-bond fluctuations found on the chip. We thus compute classical upper-bound success probabilities for different types of disorder used in the benchmarks and predict that an increase in the number of qubits will require either error correction schemes or a drastic reduction of the intrinsic noise found in these devices. We restrict this study to the exact ground state, however, the approach can be trivially extended to the inclusion of excited states if the success metric is relaxed. We outline strategies to develop robust, as well as hard benchmarks for quantum annealing devices, as well as any other (black box) computing paradigm affected by noise.

  13. Some Factors That Affecting the Performance of Mathematics Teachers in Junior High School in Medan

    ERIC Educational Resources Information Center

    Manullang, Martua; Rajagukguk, Waminton

    2016-01-01

    Some Factor's That Affecting The Mathematic Teacher Performance For Junior High School In Medan. This research will examine the effect of direct and indirect of the Organizational Knowledge towards the achievement motivation, decision making, organizational commitment, the performance of mathematics teacher. The research method is a method of…

  14. Using Representations in Geometry: A Model of Students' Cognitive and Affective Performance

    ERIC Educational Resources Information Center

    Panaoura, Areti

    2014-01-01

    Self-efficacy beliefs in mathematics, as a dimension of the affective domain, are related with students' performance on solving tasks and mainly on overcoming cognitive obstacles. The present study investigated the interrelations of cognitive performance on geometry and young students' self-efficacy beliefs about using representations for solving…

  15. Centrality and Charisma: Comparing How Leader Networks "and" Attributions Affect Team Performance

    ERIC Educational Resources Information Center

    Balkundi, Prasad; Kilduff, Martin; Harrison, David A.

    2011-01-01

    When leaders interact in teams with their subordinates, they build social capital that can have positive effects on team performance. Does this social capital affect team performance because subordinates come to see the leader as charismatic? We answered this question by examining 2 models. First, we tested the charisma-to-centrality model…

  16. The Developmental Dynamics of Children's Academic Performance and Mothers' Homework-Related Affect and Practices

    ERIC Educational Resources Information Center

    Silinskas, Gintautas; Kiuru, Noona; Aunola, Kaisa; Lerkkanen, Marja-Kristiina; Nurmi, Jari-Erik

    2015-01-01

    This study investigated the longitudinal associations between children's academic performance and their mothers' affect, practices, and perceptions of their children in homework situations. The children's (n = 2,261) performance in reading and math was tested in Grade 1 and Grade 4, and the mothers (n = 1,476) filled out questionnaires on their…

  17. Affective Cues and Processing Strategy: Color-Coded Examination Forms Influence Performance.

    ERIC Educational Resources Information Center

    Sinclair, Robert C.; Soldat, Alexander S.; Mark, Melvin M.

    1998-01-01

    Argues that external cues provide affective information that influence processing strategy and, therefore, examination performance. Notes the differences in performance for two midterm examinations, identical, except that they were printed on blue and red paper. Discusses a method for appropriately adjusting scores to control for form effects.…

  18. Performance Assessment in CTE: Focusing on the Cognitive, Psychomotor ...and Affective Domains

    ERIC Educational Resources Information Center

    Washer, Bart; Cochran, Lori

    2012-01-01

    When a student is performing in the psychomotor domain, the authors believe the student is also performing in the cognitive domain (sequencing steps, evaluating the situation) and in the affective domain (appreciating a job well done, quality control, safety). As Dabney Doty, former instructor at the University of Central Missouri, stated, "There…

  19. The developmental dynamics of children's academic performance and mothers' homework-related affect and practices.

    PubMed

    Silinskas, Gintautas; Kiuru, Noona; Aunola, Kaisa; Lerkkanen, Marja-Kristiina; Nurmi, Jari-Erik

    2015-04-01

    This study investigated the longitudinal associations between children's academic performance and their mothers' affect, practices, and perceptions of their children in homework situations. The children's (n = 2,261) performance in reading and math was tested in Grade 1 and Grade 4, and the mothers (n = 1,476) filled out questionnaires on their affect, practices, and perceptions while their children were in Grades 2, 3, and 4. The results showed, first, that the more help in homework the mothers reported, the slower was the development of their children's academic performance from Grade 1 to Grade 4. This negative association was true especially if mothers perceived their children not to be able to work autonomously. Second, children's good academic performance in Grade 1 predicted mothers' perception of child's ability to be autonomous and positive affect in homework situations later on, whereas poor performance predicted mothers' negative affect, help, and monitoring. Finally, mothers' negative affect mediated the association between children's poor performance, maternal practices, and perceptions of their children.

  20. Evening electronic device use: The effects on alertness, sleep and next-day physical performance in athletes.

    PubMed

    Jones, Maddison J; Peeling, Peter; Dawson, Brian; Halson, Shona; Miller, Joanna; Dunican, Ian; Clarke, Michael; Goodman, Carmel; Eastwood, Peter

    2017-02-14

    The aim of the present study was to investigate the influence of different types of tasks performed with or without an electronic device (tablet) on pre-sleep alertness, subsequent sleep quality and next-day athletic performance. Eight highly trained netball players attended a sleep laboratory for pre-sleep testing, polysomnographic sleep monitoring and next-day physical performance testing on 5 separate occasions (1 familiarisation and 4 experimental sessions). For 2 h prior to bedtime, athletes completed cognitively stimulating tasks (puzzles) or passive tasks (reading) with or without a tablet. Sleepiness tended to be greater after reading compared to completing puzzles without a tablet (d = 0.80), but not with a tablet. Melatonin concentration increased more so after reading compared to completing puzzles on a tablet (P = 0.02). There were no significant differences in sleep quality or quantity or next-day athletic performance between any of the conditions. These data suggest that using a tablet for 2 h prior to sleep does not negatively affect subsequent sleep or next-day performance in athletes.

  1. DEVICE TECHNOLOGY. Nanomaterials in transistors: From high-performance to thin-film applications.

    PubMed

    Franklin, Aaron D

    2015-08-14

    For more than 50 years, silicon transistors have been continuously shrunk to meet the projections of Moore's law but are now reaching fundamental limits on speed and power use. With these limits at hand, nanomaterials offer great promise for improving transistor performance and adding new applications through the coming decades. With different transistors needed in everything from high-performance servers to thin-film display backplanes, it is important to understand the targeted application needs when considering new material options. Here the distinction between high-performance and thin-film transistors is reviewed, along with the benefits and challenges to using nanomaterials in such transistors. In particular, progress on carbon nanotubes, as well as graphene and related materials (including transition metal dichalcogenides and X-enes), outlines the advances and further research needed to enable their use in transistors for high-performance computing, thin films, or completely new technologies such as flexible and transparent devices.

  2. Effect of Copolymer Chain Architecture on Active Layer Morphology and Device Performance

    NASA Astrophysics Data System (ADS)

    Amonoo, Jojo; Li, Anton; Sykes, Matthew; Huang, Bingyuan; Palermo, Edmund; McNeil, Anne; Shtein, Max; Green, Peter

    2014-03-01

    The optimum morphological structure that determines the device performance of bulk heterojunction thin film polymer solar cells is greatly influenced by the extent of phase separation between the polymer and fullerene components, which ultimately defines the length scales and purity of the donor- and acceptor-rich phases. Block copolymer thin films have been widely studied for their ability to microphase separate into well-defined nanostructures. Nickel-catalyzed chain-growth copolymerizations of thiophene and selenophene derivatives afforded well-defined π-conjugated copolymers of poly(3-hexylthiophene) (P3HT) and poly(3-hexylselenophene) (P3HS) to achieve diblock, random and gradient copolymer chain architectures. This allowed us to study the effect of copolymer sequence and nanoscale morphology of P3HT-P3HS copolymer/[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) on device performance. With the use of energy-filtered transmission electron microscopy and conductive and photoconductive atomic force microscopy we found that copolymer sequence strongly influences the phase separation capabilities of the copolymer-fullerene blend in bulk heterojunction organic photovoltaic devices.

  3. Enhanced performance of semitransparent inverted organic photovoltaic devices via a high reflector structure.

    PubMed

    Zhang, Dan-Dan; Jiang, Xiao-Chen; Wang, Rong; Xie, Hao-Jun; Ma, Guo-Fu; Ou, Qing-Dong; Chen, Yuan-Li; Li, Yan-Qing; Tang, Jian-Xin

    2013-10-23

    Significantly enhanced performances of semitransparent inverted organic photovoltaic devices have been realized by simply introducing a high reflector structure, which comprises several pairs of MoO3/LiF with a thickness of 60 nm for MoO3 and 90 nm for LiF, respectively. After optimizing the reflector structure, the enhanced light harvesting is achieved, and thus the increased optical current is obtained. The short-circuit current density (JSC) and power conversion efficiency (PCE) are increased to 10.9 mA cm(-2) and 4.32%, compared to 8.09 mA cm(-2) and 3.36% in the control device. This leads to a 30% enhancement in PCE. According to the experimental and simulated results, the improved performance is attributed to the effective reflection of light at the wavelength from 450 to 600 nm, which corresponds to the absorption range of the active layer. The demonstrated light-trapping approach is expected to be an effective method to realize the high efficiency in semitransparent organic photovoltaic devices.

  4. Two-year performance study of porous, thermoset, shape memory polyurethanes intended for vascular medical devices

    NASA Astrophysics Data System (ADS)

    Weems, Andrew C.; Boyle, Anthony J.; Maitland, Duncan J.

    2017-03-01

    The long-term shape-recovery behavior of shape memory polymers has often been shown to be dependent on the length of time the material has been stored in the secondary shape. Typically, recovery performance and shape fixity will decrease with increased time in the secondary shape. In medical materials, a shelf-life is crucial to establish as it sets the upper threshold for device performance in a clinical setting, and a reduction in shape recovery would limit the development of SMP medical devices. Here, we present a two-year study of strain recovery, strain fixity, and shape recovery kinetics for passively and actively actuated SMPs intended for vascular devices. While kinetic experiments using immersion DMA indicate slight material relaxation and a decrease in the time to recovery, these changes are not found for bulk recovery experiments. The results indicate that a two-year shelf-life for these SMPs is very reasonable, as there is no change in the recovery kinetics, strain recovery, or strain fixity associated with this aging time. Further, a thermal accelerated aging test is presented for more rapid testing of the shape memory behavior of these SMPs and is compared with the real time aging results, indicating that this test is a reasonable indicator of the two-year behavior.

  5. Analysis of plasticizers in PVC medical devices: Performance comparison of eight analytical methods.

    PubMed

    Bernard, L; Bourdeaux, D; Pereira, B; Azaroual, N; Barthélémy, C; Breysse, C; Chennell, P; Cueff, R; Dine, T; Eljezi, T; Feutry, F; Genay, S; Kambia, N; Lecoeur, M; Masse, M; Odou, P; Radaniel, T; Simon, N; Vaccher, C; Verlhac, C; Yessad, M; Décaudin, B; Sautou, V

    2017-01-01

    A wide variety of medical devices (MDs) used in hospitals are made of flexible plasticized polyvinylchloride (PVC). Different plasticizers are present in variable amounts in the PVC matrix of the devices and can leach out into the infused solutions and may enter into contact with the patients. The ARMED(1) project aims to assess the migration of these plasticizers from medical devices and therefore the level of exposure in patients. For the first task of the project, eight methods were developed to directly detect and quantify the plasticizers in the PVC matrix of the MDs. We compared the overall performances of the analytical methods using standardized and validated criteria in order to provide the scientific community with the guidance and the technical specifications of each method for the intended application. We have shown that routine rapid screening could be performed directly on the MDs using the FTIR technique, with cost-effective analyses. LC techniques may also be used, but with limits and only with individual quantification of the main plasticizers expected in the PVC matrix. GC techniques, especially GC-MS, are both more specific and more sensitive than other techniques. NMR is a robust and specific technique to precisely discriminate all plasticizers in a MD but is limited by its cost and its low ability to detect and quantify plasticizer contamination, e.g. by DEHP. All these results have been confirmed by a real test, called the " blind test " carried out on 10 MD samples.

  6. Factors Affecting the Performance of Hispanic and Non-Hispanic Marine Corps Enlistees

    DTIC Science & Technology

    2015-03-01

    THE PERFORMANCE OF HISPANIC AND NON-HISPANIC MARINE CORPS ENLISTEES by Matthew Curry March 2015 Thesis Advisor: Simona Tick Co-Advisor...March 20 15 Master ’s Thesis 4. TITLE AND SUBTITLE FACTORS AFFECTING THE PERFORMANCE OF HISPANIC AND NON- HISPANIC MARINE CORPS ENLISTEES 6. AUTHOR...S) Matthew Cmw 7. PERFORMING ORGANIZATION NA:i\\tiE(S) AND ADDRESS(ES) Naval Postgraduate School Monterey, CA 93943-5000 9. SPONSORING /MONITORING

  7. Size, but not experience, affects the ontogeny of constriction performance in ball pythons (Python regius).

    PubMed

    Penning, David A; Dartez, Schuyler F

    2016-03-01

    Constriction is a prey-immobilization technique used by many snakes and is hypothesized to have been important to the evolution and diversification of snakes. However, very few studies have examined the factors that affect constriction performance. We investigated constriction performance in ball pythons (Python regius) by evaluating how peak constriction pressure is affected by snake size, sex, and experience. In one experiment, we tested the ontogenetic scaling of constriction performance and found that snake diameter was the only significant factor determining peak constriction pressure. The number of loops applied in a coil and its interaction with snake diameter did not significantly affect constriction performance. Constriction performance in ball pythons scaled differently than in other snakes that have been studied, and medium to large ball pythons are capable of exerting significantly higher pressures than those shown to cause circulatory arrest in prey. In a second experiment, we tested the effects of experience on constriction performance in hatchling ball pythons over 10 feeding events. By allowing snakes in one test group to gain constriction experience, and manually feeding snakes under sedation in another test group, we showed that experience did not affect constriction performance. During their final (10th) feedings, all pythons constricted similarly and with sufficiently high pressures to kill prey rapidly. At the end of the 10 feeding trials, snakes that were allowed to constrict were significantly smaller than their non-constricting counterparts.

  8. Stress-induced Effects Caused by 3D IC TSV Packaging in Advanced Semiconductor Device Performance

    NASA Astrophysics Data System (ADS)

    Sukharev, V.; Kteyan, A.; Choy, J.-H.; Hovsepyan, H.; Markosian, A.; Zschech, E.; Huebner, R.

    2011-11-01

    Potential challenges with managing mechanical stress and the consequent effects on device performance for advanced 3D through-silicon-via (TSV) based technologies are outlined. The paper addresses the growing need in a simulation-based design verification flow capable to analyze a design of 3D IC stacks and to determine across-die out-of-spec variations in device electrical characteristics caused by the layout and through-silicon-via (TSV)/package-induced mechanical stress. The limited characterization/measurement capabilities for 3D IC stacks and a strict "good die" requirement make this type of analysis critical for the achievement of an acceptable level of functional and parametric yield and reliability. The paper focuses on the development of a design-for-manufacturability (DFM) type of methodology for managing mechanical stresses during a sequence of designs of 3D TSV-based dies, stacks and packages. A set of physics-based compact models for a multi-scale simulation to assess the mechanical stress across the device layers in silicon chips stacked and packaged with the 3D TSV technology is proposed. A calibration technique based on fitting to measured stress components and electrical characteristics of the test-chip devices is presented. A strategy for generation of a simulation feeding data and respective materials characterization approach are proposed, with the goal to generate a database for multi-scale material parameters of wafer-level and package-level structures. For model validation, high-resolution strain measurements in Si channels of the test-chip devices are needed. At the nanoscale, the transmission electron microscopy (TEM) is the only technique available for sub-10 nm strain measurements so far.

  9. The effects of heavy ion radiation on digital micromirror device performance

    NASA Astrophysics Data System (ADS)

    Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan D.; Pellish, Jonathan A.; Robberto, Massimo; Heap, Sara

    2016-07-01

    There is a pressing need in the astronomical community for space-suitable multi-object spectrometers (MOSs). Several digital micromirror device (DMD)-based prototype MOSs have been developed for ground-based observatories; however, their main use will come with deployment on a space based mission. Therefore, performance of DMDs under exoatmospheric radiation needs to be evaluated. In our previous work we demonstrated that DMDs are tolerant to heavy ion irradiation in general and calculated upset rate of 4.3 micromirrors in 24 hours in orbit for 1-megapixel device. The goal of this additional experiment was to acquire more data and therefore increase the accuracy of the predicted in-orbit micromirror upset rate. Similar to the previous experiment, for this testing 0.7 XGA DMDs were re-windowed with 2 μm thick pellicle and tested under accelerated heavy-ion radiation (with control electronics shielded from radiation) with a focus on detection of single-event upsets (SEUs). We concentrated on ions with low levels of linear energy transfer (LET) 1.8 - 13 MeV•cm2•mg-1 to cover the most critical range of the Weibull curve for those devices. As during the previous experiment, we observed and documented non-destructive heavy ion-induced micromirror state changes. All SEUs were always cleared with a soft reset (that is, sending a new pattern to the device). The DMDs we tested did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. Based on the data obtained in the experiments we predict micromirror in-orbit upset rate of 5.6 micromirrors in 24 hours in-orbit for the tested devices. This suggests that the heavy-ion induced SEU rate burden for a DMD-based instrument will be manageable when exposed to solar particle fluxes and cosmic rays in orbit.

  10. Performance evaluation of hybrid VLC using device cost and power over data throughput criteria

    NASA Astrophysics Data System (ADS)

    Lee, C. C.; Tan, C. S.; Wong, H. Y.; Yahya, M. B.

    2013-09-01

    Visible light communication (VLC) technology has attained its attention in both academic and industry lately. It is determined by the development of light emitting diode (LED) technology for solid-state lighting (SSL).It has great potential to gradually replace radio frequency (RF) wireless technology because it offers unregulated and unlicensed bandwidth to withstand future demand of indoor wireless access to real-time bandwidth-demanding applications. However, it was found to provide intrusive uplink channel that give rise to unpleasant irradiance from the user device which could interfere with the downlink channel of VLC and hence limit mobility to users as a result of small coverage (field of view of VLC).To address this potential problem, a Hybrid VLC system which integrates VLC (for downlink) and RF (for uplink) technology is proposed. It offers a non-intrusive RF back channel that provides high throughput VLC and maintains durability with conventional RF devices. To deploy Hybrid VLC system in the market, it must be energy and cost saving to attain its equivalent economical advantage by comparing to existing architecture that employs fluorescent or LED lights with RF technology. In this paper, performance evaluation on the proposed hybrid system was carried out in terms of device cost and power consumption against data throughput. Based on our simulation, Hybrid VLC system was found to reduce device cost by 3% and power consumption by 68% when compares to fluorescent lights with RF technology. Nevertheless, when it is compared to LED lights with RF technology, our proposed hybrid system is found to achieve device cost saving as high as 47% and reduced power consumption by 49%. Such promising results have demonstrated that Hybrid VLC system is a feasible solution and has paved the way for greater cost saving and energy efficient compares with the current RF architecture even with the increasing requirement of indoor area coverage.

  11. Novel variable volume injector for performing sample introduction in a miniaturised isotachophoresis device.

    PubMed

    Baldock, S J; Fielden, P R; Goddard, N J; Kretschmer, H R; Prest, J E; Treves Brown, B J

    2004-07-09

    A microdevice design furnished with a novel sample injector, capable of delivering variable volume samples, for miniaturised isotachophoretic separations is presented. Micromachining by direct milling was used to realise two flow channel network designs on poly(methyl methacrylate) chips. Both designs comprised a wide bore sample channel interfaced, via a short connection channel, to a narrow bore separation channel. Superior injection performance was observed with a connection channel angled at 45 degrees to the separation channel compared to a device using a channel angled at 90 degrees. Automated delivery of electrolytes to the microdevice was demonstrated with both hydrostatic pumping and syringe pumps; both gave reproducible sample injection. A range of different sampling strategies were investigated. Isotachophoretic separations of model analytes (metal ions and an anionic dye) demonstrated the potential of the device. Separations of ten metal cations were achieved in under 475 s.

  12. The aerodynamic performance of several flow control devices for internal flow systems

    NASA Technical Reports Server (NTRS)

    Eckert, W. T.; Wettlaufer, B. M.; Mort, K. W.

    1982-01-01

    An experimental reseach and development program was undertaken to develop and document new flow-control devices for use in the major modifications to the 40 by 80 Foot wind tunnel at Ames Research Center. These devices, which are applicable to other facilities as well, included grid-type and quasi-two-dimensional flow straighteners, louver panels for valving, and turning-vane cascades with net turning angles from 0 deg to 90 deg. The tests were conducted at model scale over a Reynolds number range from 2 x 100,000 to 17 x 100,000, based on chord. The results showed quantitatively the performance benefits of faired, low-blockage, smooth-surface straightener systems, and the advantages of curved turning-vanes with hinge-line gaps sealed and a preferred chord-to-gap ratio between 2.5 and 3.0 for 45 deg or 90 deg turns.

  13. Functionalized graphene for high-performance two-dimensional spintronics devices.

    PubMed

    Li, Linze; Qin, Rui; Li, Hong; Yu, Lili; Liu, Qihang; Luo, Guangfu; Gao, Zhengxiang; Lu, Jing

    2011-04-26

    Using first-principles calculations, we explore the possibility of functionalized graphene as a high-performance two-dimensional spintronics device. Graphene functionalized with O on one side and H on the other side in the chair conformation is found to be a ferromagnetic metal with a spin-filter efficiency up to 54% at finite bias. The ground state of graphene semifunctionalized with F in the chair conformation is an antiferromagnetic semiconductor, and we construct a spin-valve device from it by introducing a magnetic field to stabilize its metallic ferromagnetic state. The resulting room-temperature magnetoresistance is up to 2200%, which is 1 order of magnitude larger than the available experimental values.

  14. Defects in silicon effect on device performance and relationship to crystal growth conditions

    NASA Technical Reports Server (NTRS)

    Jastrzebski, L.

    1985-01-01

    A relationship between material defects in silicon and the performance of electronic devices will be described. A role which oxygen and carbon in silicon play during the defects generation process will be discussed. The electronic properties of silicon are a strong function of the oxygen state in the silicon. This state controls mechanical properties of silicon efficiency for internal gettering and formation of defects in the device's active area. In addition, to temperature, time, ambience, and the cooling/heating rates of high temperature treatments, the oxygen state is a function of the crystal growth process. The incorporation of carbon and oxygen into silicon crystal is controlled by geometry and rotation rates applied to crystal and crucible during crystal growths. Also, formation of nucleation centers for oxygen precipitation is influenced by the growth process, although there is still a controversy which parameters play a major role. All these factors will be reviewed with special emphasis on areas which are still ambiguous and controversial.

  15. Performance Enhancement of PFET Planar Devices by Plasma Immersion Ion Implantation (P3I)

    SciTech Connect

    Ortolland, Claude; Horiguchi, Naoto; Kerner, Christoph; Chiarella, Thomas; Eyben, Pierre; Everaert, Jean-Luc; Hoffmann, Thomas; Del Agua Borniquel, Jose Ignacio; Poon, Tze; Santhanam, Kartik; Porshnev, Peter; Foad, Majeed; Schreutelkamp, Robert; Absil, Philippe; Vandervorst, Wilfried; Felch, Susan

    2008-11-03

    A study of doping the pMOS Lightly Doped Drain (LDD) by Plasma Immersion Ion Implantation (P3i) with BF3 is presented which demonstrates a better transistor performance compared to standard beam line Ion Implantation (I/I). The benefit of P3i comes from the broad angular distribution of the impinging ions thereby doping the poly-silicon gate sidewall as well. Gate capacitance of short channel devices has been measured and clearly shows this improvement. This model is clearly supported by high resolution 2D-carrier profiles using Scanning Spreading Resistance Microscopy (SSRM) which shows this gate sidewall doping. The broad angular distribution also implies a smaller directional sensitivity (to for instance the detailed gate edge shape) and leads to devices which are perfectly balanced, when Source and Drain electrode are switched.

  16. A new high performance field reversed configuration operating regime in the C-2 device

    SciTech Connect

    Tuszewski, M.; Smirnov, A.; Thompson, M. C.; Barnes, D.; Binderbauer, M. W.; Brown, R.; Bui, D. Q.; Clary, R.; Conroy, K. D.; Deng, B. H.; Dettrick, S. A.; Douglass, J. D.; Garate, E.; Glass, F. J.; Gota, H.; Guo, H.Y.; Gupta, D.; Gupta, S.; Kinley, J. S.; Knapp, K.; and others

    2012-05-15

    Large field reversed configurations (FRCs) are produced in the C-2 device by combining dynamic formation and merging processes. The good confinement of these FRCs must be further improved to achieve sustainment with neutral beam (NB) injection and pellet fuelling. A plasma gun is installed at one end of the C-2 device to attempt electric field control of the FRC edge layer. The gun inward radial electric field counters the usual FRC spin-up and mitigates the n = 2 rotational instability without applying quadrupole magnetic fields. Better plasma centering is also obtained, presumably from line-tying to the gun electrodes. The combined effects of the plasma gun and of neutral beam injection lead to the high performance FRC operating regime, with FRC lifetimes up to 3 ms and with FRC confinement times improved by factors 2 to 4.

  17. Intrinsic electrical transport and performance projections of synthetic monolayer MoS2 devices

    NASA Astrophysics Data System (ADS)

    Smithe, Kirby K. H.; English, Chris D.; Suryavanshi, Saurabh V.; Pop, Eric

    2017-03-01

    We demonstrate monolayer (1L) MoS2 grown by chemical vapor deposition (CVD) with transport properties comparable to those of the best exfoliated 1L devices over a wide range of carrier densities (up to ˜1013 cm-2) and temperatures (80-500 K). Transfer length measurements decouple the intrinsic material mobility from the contact resistance, at practical carrier densities (>1012 cm-2). We demonstrate the highest current density reported to date (˜270 μA μm-1 or 44 MA cm-2) at 300 K for an 80 nm long device from CVD-grown 1L MoS2. Using simulations, we discuss what improvements of 1L MoS2 are still required to meet technology roadmap requirements for low power and high performance applications. Such results are an important step towards large-area electronics based on 1L semiconductors.

  18. Synthesis of Large Area Graphene for High Performance in Flexible Optoelectronic Devices

    PubMed Central

    Polat, Emre O.; Balci, Osman; Kakenov, Nurbek; Uzlu, Hasan Burkay; Kocabas, Coskun; Dahiya, Ravinder

    2015-01-01

    This work demonstrates an attractive low-cost route to obtain large area and high-quality graphene films by using the ultra-smooth copper foils which are typically used as the negative electrodes in lithium-ion batteries. We first compared the electronic transport properties of our new graphene film with the one synthesized by using commonly used standard copper foils in chemical vapor deposition (CVD). We observed a stark improvement in the electrical performance of the transistors realized on our graphene films. To study the optical properties on large area, we transferred CVD based graphene to transparent flexible substrates using hot lamination method and performed large area optical scanning. We demonstrate the promise of our high quality graphene films for large areas with ~400 cm2 flexible optical modulators. We obtained a profound light modulation over a broad spectrum by using the fabricated large area transparent graphene supercapacitors and we compared the performance of our devices with the one based on graphene from standard copper. We propose that the copper foils used in the lithium-ion batteries could be used to obtain high-quality graphene at much lower-cost, with the improved performance of electrical transport and optical properties in the devices made from them. PMID:26578425

  19. Causal attribution and affective response as mediated by task performance and self-acceptance.

    PubMed

    Green, T D; Bailey, R C; Zinser, O; Williams, D E

    1994-12-01

    Predictions derived from cognitive consistency theories, self-esteem theories, and ego-serving-bias theory concerning how students would make attributional and affective responses to their academic performance were investigated. 202 university students completed a measure of self-acceptance of their college ability and made attributional and affective responses to an hypothetical examination performance. Analyses showed that students receiving positive feedback perceived greater internal causality and responded with greater positive affect than students receiving negative feedback. Self-acceptance did not moderate the attributions or affective reactions. The results supported the ego-serving-bias theory and provided partial support for self-esteem theory. Findings did not support predictions from cognitive-consistency theory.

  20. Improving performance and lifetime of small-molecule organic photovoltaic devices by using bathocuproine-fullerene cathodic layer.

    PubMed

    Liu, Shun-Wei; Lee, Chih-Chien; Su, Wei-Cheng; Yuan, Chih-Hsien; Shu, Yi-Sheng; Chang, Wen-Chang; Guo, Jhih-Yan; Chiu, Chien-Feng; Li, Ya-Ze; Su, Tsung-Hao; Chen, Kuan-Ting; Chang, Po-Chien; Yeh, Tzu-Hung; Liu, Yu-Hsuan

    2015-05-06

    In this study, we compared the use of neat bathocuproine (BCP) and BCP:C60 mixed buffer layers in chloroboron subphthalocyanine (SubPc)/C60 bilayer organic photovoltaic (OPV) devices and analyzed their influence on device performance. Replacing the conventional BCP with BCP:C60 enabled manipulating the optical field distribution for optimizing the optical properties of the devices. Estimation of the interfacial barrier indicated that the insertion of the BCP:C60 between the C60 and electrode can effectively reduce the barrier for electrons and enhance electron collection at the electrode. Temperature-dependent measurements of the OPV devices performed to calculate the barrier height at the SubPc/C60 interface suggested that band bending was larger when the BCP:C60 buffer layer was used, reflecting increased exciton dissociation efficiency. In addition, the device lifetime was considerably improved when the BCP:C60 buffer layer was used. The device performance was stabilized after the photodegradation of the active layers, thereby increasing the device lifetime compared with the use of the neat BCP buffer layer. Atomic force microscopy images showed that the neat BCP was easily crystallized and could degrade the cathodic interface, whereas the blend of C60 and BCP suppressed the crystallization of BCP. Therefore, the optimal buffer layer improved both the device performance and the device lifetime.

  1. Improvement of device performance by using zinc oxide in hybrid organic-inorganic solar cells

    NASA Astrophysics Data System (ADS)

    Hayakawa, Akinobu; Sagawa, Takashi

    2016-02-01

    Zinc oxide (ZnO) nanopowder was applied to hybrid solar cells in combination with poly(3-hexylthiophene). Stability tests of the hybrid solar cell with or without encapsulation with glass and UV cut-off films were performed under 1 sun at 63 °C at a relative humidity of 50%. It was found that the sealed cell showed worse device performance in terms of the loss of the open-circuit voltage (Voc), whereas the unsealed cell exposed to air retained an almost constant Voc for more than 3 d under dark and atmospheric conditions. Placement in O2 atmosphere in the dark led to the recovery of Voc. Cation (Sn4+) doping into ZnO was performed, and the loss of Voc was effectively suppressed through the restraint of the supply of the excited electron from the valence band to the conduction band.

  2. Toward high-performance quality meeting IC device manufacturing requirements with AZ SMART DSA process

    NASA Astrophysics Data System (ADS)

    Kim, JiHoon; Yin, Jian; Cao, Yi; Her, YoungJun; Petermann, Claire; Wu, Hengpeng; Shan, Jianhui; Tsutsumi, Tomohiko; Lin, Guanyang

    2015-03-01

    Significant progresses on 300 mm wafer level DSA (Directed Self-Assembly) performance stability and pattern quality were demonstrated in recent years. DSA technology is now widely regarded as a leading complementary patterning technique for future node integrated circuit (IC) device manufacturing. We first published SMARTTM DSA flow in 2012. In 2013, we demonstrated that SMARTTM DSA pattern quality is comparable to that generated using traditional multiple patterning technique for pattern uniformity on a 300 mm wafer. In addition, we also demonstrated that less than 1.5 nm/3σ LER (line edge roughness) for 16 nm half pitch DSA line/space pattern is achievable through SMARTTM DSA process. In this publication, we will report impacts on SMARTTM DSA performances of key pre-pattern features and processing conditions. 300mm wafer performance process window, CD uniformity and pattern LER/LWR after etching transfer into carbon-hard mask will be discussed as well.

  3. The impact of target luminance and radiance on night vision device visual performance testing

    NASA Astrophysics Data System (ADS)

    Marasco, Peter L.; Task, H. Lee

    2003-09-01

    Visual performance through night-vision devices (NVDs) is a function of many parameters such as target contrast, objective and eyepiece lens focus, signal/noise of the image intensifier tube, quality of the image intensifier, night-vision goggle (NVG) gain, and NVG output luminance to the eye. The NVG output luminance depends on the NVG sensitive radiance emitted (or reflected) from the visual acuity target (usually a vision testing chart). The primary topic of this paper is the standardization (or lack thereof) of the radiance levels used for NVG visual acuity testing. The visual acuity chart light level might be determined in either photometric (luminance) units or radiometric (radiance) units. The light levels are often described as "starlight," "quarter moon," or "optimum" light levels and may not actually provide any quantitative photometric or radiometric information. While these terms may be useful to pilots and the users of night-vision devices, they are inadequate for accurate visual performance testing. This is because there is no widely accepted agreement in the night vision community as to the radiance or luminance level of the target that corresponds to the various named light levels. This paper examines the range of values for "starlight," "quarter moon," and "optimum" light commonly used by the night vision community and referenced in the literature. The impact on performance testing of variations in target luminance/radiance levels is also examined. Arguments for standardizing on NVG-weighted radiometric units for testing night-vision devices instead of photometric units are presented. In addition, the differences between theoretical weighted radiance and actual weighted radiance are also discussed.

  4. Influences of an Aluminum Covering Layer on the Performance of Cross-Like Hall Devices.

    PubMed

    Lyu, Fei; Liu, Xinfu; Ding, Yinjie; Toh, Eng-Huat; Zhang, Zhenyan; Pan, Yifan; Wang, Zhen; Li, Chengjie; Li, Li; Sha, Jin; Pan, Hongbing

    2016-01-15

    This work studies the effects of an aluminum covering on the performance of cross-like Hall devices. Four different Hall sensor structures of various sizes were designed and fabricated. The sensitivity and offset of the Hall sensors, two key points impacting their performance, were characterized using a self-built measurement system. The work analyzes the influences of the aluminum covering on those two aspects of the performance. The aluminum layer covering mainly leads to an eddy-current effect in an unstable magnetic field and an additional depletion region above the active region. Those two points have influences on the sensitivity and the offset voltage, respectively. The analysis guides the designer whether to choose covering with an aluminum layer the active region of the Hall sensor as a method to reduce the flicker noise and to improve the stability of the Hall sensor. Because Hall devices, as a reference element, always suffer from a large dispersion, improving their stability is a crucial issue.

  5. Test controller design, implementation, and performance for a magnetic suspension continuous flow ventricular assist device.

    PubMed

    Hilton, E F; Allaire, P E; Wei, N; Baloh, M J; Bearnson, G; Olsen, D B; Khanwilkar, P

    1999-08-01

    A new continuous flow ventricular assist device using full magnetic suspension has been designed, constructed, and tested. The magnetic suspension centers the centrifugal pump impeller within the clearance passages in the pump, thus avoiding any form of contact. The noncontact operation is designed to give very high expected mechanical reliability, large clearances, low hemolysis, and a relatively small size compared to current pulsatile devices. A unique configuration of magnetic actuators on the inlet side and exit sides of the impeller provides full 5 axis control and suspension of the impeller. The bearing system is divided into segments which allow for 3 displacement axes and 2 angular control axes. The controller chosen for the first suspension tests consists of a decentralized set of 5 proportional integral derivative (PID) controllers. This document describes both the controller and an overview of some results pertaining to the magnetic bearing performance. The pump has been successfully operated in both water and blood under design conditions suitable for use as a ventricular assist device.

  6. Kilopixel X-Ray Microcalorimeter Arrays for Astrophysics: Device Performance and Uniformity

    NASA Technical Reports Server (NTRS)

    Eckart, M. E.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Porst, J.-P.; Sadleir, J. E.; Smith, S. J.

    2012-01-01

    We are developing kilopixel arrays of TES microcalorimeters to enable high-resolution x-ray imaging spectrometers for future x-ray observatories and laboratory astrophysics experiments. Our current array design was targeted as a prototype for the X-ray Microcalorimeter Spectrometer proposed for the International X-ray Observatory, which calls for a 40×40-pixel core array of 300 micron devices with 2.5 eV energy resolution (at 6 keV). Here we present device characterization of our 32×32 arrays, including x-ray spectral performance of individual pixels within the array. We present our results in light of the understanding that our Mo/Au TESs act as weak superconducting links, causing the TES critical current (I(sub c)) and transition shape to oscillate with applied magnetic field (B). We show I(sub c)(B) measurements and discuss the uniformity of these measurements across the array, as well as implications regarding the uniformity of device noise and response. In addition, we are working to reduce pixel-to-pixel electrical and thermal crosstalk; we present recent test results from an array that has microstrip wiring and an angle-evaporated copper backside heatsinking layer, which provides copper coverage on the four sidewalls of the silicon wells beneath each pixel.

  7. The insulation performance of reactive parylene films in implantable electronic devices

    PubMed Central

    Seymour, John P.; Elkasabi, Yaseen; Chen, Hsien-yeh; Lahann, Joerg; Kipke, Daryl R.

    2009-01-01

    Parylene-C (poly-chloro-p-xylylene) is an appropriate material for use in an implantable, microfabricated device. It is hydrophobic, conformally deposited, has a low dielectric constant, and superb biocompatibility. Yet for many bioelectrical applications, its poor wet adhesion may be an impassable shortcoming. This research contrasts parylene-C and poly(p-xylylene) functionalized with reactive group X (PPX-X) layers using long-term electrical soak and adhesion tests. The reactive parylene was made of complementary derivatives having aldehyde and aminomethyl side groups (PPX-CHO and PPX-CH2NH2 respectively). These functional groups have previously been shown to covalently react together after heating. Electrical testing was conducted in saline at 37°C on interdigitated electrodes with either parylene-C or reactive parylene as the metal layer interface. Results showed that reactive parylene devices maintained the highest impedance. Heat-treated PPX-X device impedance was 800% greater at 10 kHz and 70% greater at 1Hz relative to heated parylene-C controls after 60 days. Heat treatment proved to be critical for maintaining high impedance of both parylene-C and the reactive parylene. Adhesion measurements showed improved wet metal adhesion for PPX-X, which corresponds well with its excellent high frequency performance. PMID:19703712

  8. Kilopixel X-Ray Microcalorimeter Arrays for Astrophysics: Device Performance and Uniformity

    NASA Technical Reports Server (NTRS)

    Eckart, M. E.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Chervenak, F. M.

    2011-01-01

    We are developing kilo-pixel arrays of TES microcalorimeters to enable high-resolution X-ray imaging spectrometers for future X-ray observatories and laboratory astrophysics experiments. Our current array design was targeted as a prototype for the X-ray Microcalorimeter Spectrometer proposed for the International X-ray Observatory, which calls for a 40x40-pixel core array of 300 micron devices with 2.5 e V energy resolution (at 6 keV). Here we present device characterization of our 32x32 arrays, including X-ray spectral performance of individual pixels within the array. We present our results in light of the understanding that our Mo/Au TESs act as weak superconducting links, causing the TES critical current (Ic) and transition shape to oscillate with applied magnetic field (B). We show Ic(B) measurements and discuss the uniformity of these measurements across the array, as well as implications regarding the uniformity of device noise and response. In addition, we are working to reduce pixel-to-pixel electrical and thermal crosstalk; we present recent test results from an array that has microstrip wiring and an angle-evaporated Cu backside heatsinking layer, which provides Cu coverage on the four sidewalls of the silicon wells beneath each pixel.

  9. The insulation performance of reactive parylene films in implantable electronic devices.

    PubMed

    Seymour, John P; Elkasabi, Yaseen M; Chen, Hsien-Yeh; Lahann, Joerg; Kipke, Daryl R

    2009-10-01

    Parylene-C (poly-chloro-p-xylylene) is an appropriate material for use in an implantable, microfabricated device. It is hydrophobic, conformally deposited, has a low dielectric constant, and superb biocompatibility. Yet for many bioelectrical applications, its poor wet adhesion may be an impassable shortcoming. This research contrasts parylene-C and poly(p-xylylene) functionalized with reactive group X (PPX-X) layers using long-term electrical soak and adhesion tests. The reactive parylene was made of complementary derivatives having aldehyde and aminomethyl side groups (PPX-CHO and PPX-CH2NH2 respectively). These functional groups have previously been shown to covalently react together after heating. Electrical testing was conducted in saline at 37 degrees C on interdigitated electrodes with either parylene-C or reactive parylene as the metal layer interface. Results showed that reactive parylene devices maintained the highest impedance. Heat-treated PPX-X device impedance was 800% greater at 10kHz and 70% greater at 1Hz relative to heated parylene-C controls after 60 days. Heat treatment proved to be critical for maintaining high impedance of both parylene-C and the reactive parylene. Adhesion measurements showed improved wet metal adhesion for PPX-X, which corresponds well with its excellent high frequency performance.

  10. Design, construction, and performance of a device for directional recrystallization of metallic alloys

    NASA Astrophysics Data System (ADS)

    Vallejos, J. M.; Leonard, M. E.; Sobrero, C. E.; La Roca, P. M.; Druker, A. V.; Malarria, J. A.

    2017-02-01

    A device was designed to apply the directional recrystallization method to Fe-based alloys in order to obtain bamboo-like microstructures. This microstructure is suitable for improving creep properties and resistance to fatigue in some alloys and for enhancing pseudoelastic properties in shape memory alloys. The design and construction of a flat coil are described in detail. In addition, we developed an electromechanical system to control the movement of a wire within the flat coil. The construction details and system performance are presented. Furthermore, metallographic studies taken from the directionally recrystallized low-carbon steel samples are shown. Nearly monocrystalline and bamboo-like microstructures were achieved in the steel wires.

  11. Design, construction, and performance of a device for directional recrystallization of metallic alloys.

    PubMed

    Vallejos, J M; Leonard, M E; Sobrero, C E; La Roca, P M; Druker, A V; Malarria, J A

    2017-02-01

    A device was designed to apply the directional recrystallization method to Fe-based alloys in order to obtain bamboo-like microstructures. This microstructure is suitable for improving creep properties and resistance to fatigue in some alloys and for enhancing pseudoelastic properties in shape memory alloys. The design and construction of a flat coil are described in detail. In addition, we developed an electromechanical system to control the movement of a wire within the flat coil. The construction details and system performance are presented. Furthermore, metallographic studies taken from the directionally recrystallized low-carbon steel samples are shown. Nearly monocrystalline and bamboo-like microstructures were achieved in the steel wires.

  12. Effects of interface roughness scattering on device performance of indirectly pumped terahertz quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Ghasem Razavipour, Seyed; Dupont, Emmanuel; Wasilewski, Zbig R.; Ban, Dayan

    2015-06-01

    The impacts of interface roughness (IR) scattering on device performance of indirectly-pumped (IDP) terahertz quantum cascade lasers are studied. Three different active region designs with almost the same lasing frequency at threshold and comparable oscillator strength are experimentally investigated and the measurement data are analyzed and compared with numerical simulation. The simulation results show that all structures suffer from the detrimental effect of intersubband roughness scattering in terms of threshold current density, and probably operating temperature. The intrasubband IR scattering time could also to be a limiting factor in the IDP structures due to the employed high energetic barrier.

  13. Ion Implantation Defects in Silicon and the Performance of Micron and Submicron Devices.

    DTIC Science & Technology

    1983-01-31

    AD-R124 497 ION IMPLANTATION DEFECTS IN SILICON AND THE PERFORMANC / OF MICRON AND SUB..(U) ILLINOIS UNIV AT URBANA COOMRNTED SCIENCE LAB B G...TEST CHART -NATINAC. BURMA OF STANWM-1*3-A ION IMPLANTATION DEFECTS IN SILICON AND THE PERFORMANCE OF MICRON AND SUBMICRON DEVICES FINAL REPORT B. G...NUMUER FINAL £7 /7_ _ _ _ _ _ _ 4. TITLE (an Swe) IL TYPE OF REPORT & PERIOD COVERED ION IMPLANTATION DEFECTS IN SILICON AND THE Final 6/80-1/16/83

  14. Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard

    NASA Astrophysics Data System (ADS)

    Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros

    2017-02-01

    Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.

  15. Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard.

    PubMed

    Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros

    2017-02-01

    Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.

  16. The Effect of High-Resistance SnO2 on CdS/CdTe Device Performance

    SciTech Connect

    Li, W.; Ribelin, R.; Mahathongdy, Y.; Albin, D.; Dhere, R.; Rose, D.; Asher, S.; Moutinho, H.; Sheldon, P.

    1998-10-06

    In this paper, we have studied the effect of high-resistance SnO2 buffer layers, deposited by low-pressure chemical-vapor deposition, on CdS/CdTe device performance. Our results indicate that when CdS/CdTe devices have a very thin layer of CdS or no CdS at all, the i-SnO2 buffer layer helps to increase device efficiency. When the CdS layer is thicker than 600{angstrom}, the device performance is dominated by CdS thickness, not the i-SnO2 layer. If a very thin CdS layer is to be used to enhance device performance, we conclude that a better SnO2 buffer layer is needed.

  17. Ultrafast laser trimming for reduced device leakage in high performance OTFT semiconductors for flexible displays

    NASA Astrophysics Data System (ADS)

    Karnakis, Dimitris; Cooke, Michael D.; Chan, Y. F.; Ogier, Simon D.

    2013-03-01

    Organic semiconductors (OSC) are solution processable synthetic materials with high carrier mobility that promise to revolutionise flexible electronics manufacturing due to their low cost, lightweight and high volume low temperature printing in reel-to-reel (R2R) [1] for applications such as flexible display backplanes (Fig.1), RFID tags, and logic/memory devices. Despite several recent technological advances, organic thin film transistor (OTFT) printing is still not production-ready due to limitations mainly with printing resolution on dimensionally unstable substrates and device leakage that reduces dramatically electrical performance. OTFTs have the source-drain in ohmic contact with the OSC material to lower contact resistance. If they are unpatterned, a leakage pathway from source to drain develops which results in non-optimum on/off currents and not controllable device uniformity (Fig.2). DPSS lasers offer several key advantages for OTFT patterning including maskless, non-contact, dry patterning, scalable large area operation with precision registration, well-suited to R2R manufacturing at overall μm size resolutions. But the thermal management of laser processing is very important as the devices are very sensitive to heat and thermomechanical damage [2]. This paper discusses 343nm picosecond laser ablation trimming of 50nm thick PTAA, TIPS pentacene and other semiconductor compounds on thin 50nm thick metal gold electrodes in a top gate configuration. It is shown that with careful optimisation, a suitable process window exists resulting in clean laser structuring without damage to the underlying layers while also containing laser debris. Several order of magnitude improvements were recorded in on/off currents up to 106 with OSC mobilities of 1 cm2/Vsec, albeit at slightly higher than optimum threshold voltages which support demanding flexible display backplane applications.

  18. Evaluating factors affecting the permeability of emulsions used to stabilize radioactive contamination from a radiological dispersal device.

    PubMed

    Fox, Garey A; Medina, Victor F

    2005-05-15

    Present strategies for alleviating radioactive contamination from a radiological dispersal device (RDD) or dirty bomb involve either demolishing and removing radioactive surfaces or abandoning portions of the area near the release point. In both cases, it is imperative to eliminate or reduce migration of the radioisotopes until the cleanup is complete or until the radiation has decayed back to acceptable levels. This research investigated an alternative strategy of using emulsions to stabilize radioactive particulate contamination. Emergency response personnel would coat surfaces with emulsions consisting of asphalt or tall oil pitch to prevent migration of contamination. The site can then be evaluated and cleaned up as needed. In order for this approach to be effective, the treatment must eliminate migration of the radioactive agents in the terror device. Water application is an environmental condition that could promote migration into the external environment. This research investigated the potential for water, and correspondingly contaminant, migration through two emulsions consisting of Topein, a resinous byproduct during paper manufacture. Topein C is an asphaltic-based emulsion and Topein S is a tall oil pitch, nonionic emulsion. Experiments included water adsorption/ mobilization studies, filtration tests, and image analysis of photomicrographs from an environmental scanning electron microscope (ESEM) and a stereomicroscope. Both emulsions were effective at reducing water migration. Conductivity estimates were on the order of 10(-80) cm s(-1) for Topein C and 10(-7) cm s(-1) for Topein S. Water mobility depended on emulsion flocculation and coalescence time. Photomicrographs indicate that Topein S consisted of greater and more interconnected porosity. Dilute foams of isolated spherical gas cells formed when emulsions were applied to basic surfaces. Gas cells rose to the surface and ruptured, leaving void spaces that penetrated throughout the emulsion. These

  19. Malaysian and Singaporean students' affective characteristics and mathematics performance: evidence from PISA 2012.

    PubMed

    Thien, Lei Mee; Ong, Mei Yean

    2015-01-01

    This paper attempts to identify the extent to which the affective characteristics of Malaysian and Singaporean students' attainment compared to the OECD average in Programme for International Student Assessment (PISA) 2012, and examine the influence of students' affective characteristics, gender, and their socioeconomic status on mathematics performance at both student and school levels. Sample consisted of 5197 and 5546 15-year-old Malaysian and Singaporean students. Data were analysed using hierarchical linear modelling approach with HLM 7.0 software. Results showed that the Index of economic, social, and cultural status (ESCS), mathematics self-efficacy, and mathematics anxiety have significant effects on mathematics performance in Malaysia and Singapore at the student level. Proportion of boys at the school level has no significant effects on mathematics performance for both Malaysian and Singaporean students. ESCS mean at the school level has positive and significant effects on mathematics performance in Malaysia, but not in Singapore. Limitations, implications, and future studies were discussed.

  20. Oral impacts affecting daily performance in a low dental disease Thai population.

    PubMed

    Adulyanon, S; Vourapukjaru, J; Sheiham, A

    1996-12-01

    The aim of the study was to measure incidence of oral impacts on daily performances and their related features in a low dental disease population. 501 people aged 35-44 years in 16 rural villages in Ban Phang district, Khon Kaen, Thailand, were interviewed about oral impacts on nine physical, psychological and social aspects of performance during the past 6 months, and then had an oral examination. The clinical and behavioural data showed that the sample had low caries (DMFT = 2.7) and a low utilization of dental services. 73.6% of all subjects had at least one daily performance affected by an oral impact. The highest incidence of performances affected were Eating (49.7%), Emotional stability (46.5%) and Smiling (26.1%). Eating, Emotional stability and Cleaning teeth performances had a high frequency or long duration of impacts, but a low severity. The low frequency performances; Physical activities, Major role activity and Sleeping were rated as high severity. Pain and discomfort were mainly perceived as the causes of impacts (40.1%) for almost every performance except Smiling. Toothache was the major causal oral condition (32.7%) of almost all aspects of performance. It was concluded that this low caries people have as high an incidence of oral impacts as industrialized, high dental disease populations. Frequency and severity presented the paradoxical effect on different performances and should both be taken into account for overall estimation of impacts.

  1. Using Mobile Devices and the Adobe Connect Web Conferencing Tool in the Assessment of EFL Student Teacher Performance

    ERIC Educational Resources Information Center

    Bolona Lopez, Maria del Carmen; Ortiz, Margarita Elizabeth; Allen, Christopher

    2015-01-01

    This paper describes a project to use mobile devices and video conferencing technology in the assessment of student English as a Foreign Language (EFL) teacher performance on teaching practice in Ecuador. With the increasing availability of mobile devices with video recording facilities, it has become easier for trainers to capture teacher…

  2. [Research on the performance comparing and building of affective computing database based on physiological parameters].

    PubMed

    Li, Xin; Du, Xiaojuan; Zhang, Yunpeng; Ying, Lijuan; Li, Changwuz

    2014-08-01

    The validity and reasonableness of emotional data are the key issues in the cognitive affective computing research. Effects of the emotion recognition are decided by the quality of selected data directly. Therefore, it is an important part of affective computing research to build affective computing database with good performance, so that it is the hot spot of research in this field. In this paper, the performance of two classical cognitive affective computing databases, the Massachusetts Institute of Technology (MIT) cognitive affective computing database and Germany Augsburg University emotion recognition database were compared, their data structure and data types were compared respectively, and emotional recognition effect based on the data were studied comparatively. The results indicated that the analysis based on the physical parameters could get the effective emotional recognition, and would be a feasible method of pressure emotional evaluation. Because of the lack of stress emotional evaluation data based on the physiological parameters domestically, there is not a public stress emotional database. We hereby built a dataset for the stress evaluation towards the high stress group in colleges, candidates of postgraduates of Ph. D and master as the subjects. We then acquired their physiological parameters, and performed the pressure analysis based on this database. The results indicated that this dataset had a certain reference value for the stress evaluation, and we hope this research can provide a reference and support for emotion evaluation and analysis.

  3. The effects of control order, feedback, practice, and input device on tracking performance and perceived workload

    NASA Technical Reports Server (NTRS)

    Hancock, P. A.; Robinson, M. A.

    1989-01-01

    The present experiment examined the influence of several task-related factors on tracking performance and concomitant workload. The manipulated factors included tracking order, the presence or absence of knowledge of performance, and the control device. Summed root mean square error (rmse) and perceived workload were measured at the termination of each trial. Perceived workload was measured using the NASA Task Load Index (TLX) and the Subjective Workload Assessment Technique (SWAT). Results indicated a large and expected effect for track order on both performance and the perception of load. In general, trackball input was more accurate and judged for lower load than input using a mouse. The presence or absence of knowledge of performance had little effect on either performance or workload. There were a number of interactions between factors shown in performance that were mirrored by perceived workload scores. Results from each workload scale were equivalent in terms of sensitivity to task manipulations. The pattern of results affirm the utility of these workload measures in assessing the imposed load of multiple task-related variables.

  4. Feasibility study of performing IGRT system daily QA using a commercial QA device.

    PubMed

    Peng, Jean L; Kahler, Darren; Li, Jonathan G; Amdur, Robert J; Vanek, Kenneth N; Liu, Chihray

    2011-06-01

    The purpose of this study was to investigate the feasibility of using a single QA device for comprehensive, efficient daily QA of a linear accelerator (Linac) and three image-guided stereotactic positioning systems (IGSPSs). The Sun Nuclear Daily QA 3 (DQA3) device was used to perform daily dosimetry and mechanical accuracy tests for an Elekta Linac, as well as daily image geometric and isocenter coincidence accuracy tests for three IGSPSs: the AlignRT surface imaging system; the frameless SonArray optical tracking System (FSA) and the Elekta kV CBCT. The DQA3 can also be used for couch positioning, repositioning, and rotational tests during the monthly QA. Based on phantom imaging, the Linac coordinate system determined using AlignRT was within 0.7 mm/0.6° of that of the CBCT system. The difference is attributable to the different calibration methods that are utilized for these two systems. The laser alignment was within 0.5 mm of the isocenter location determined with the three IGSPSs. The ODI constancy was ± 0.5 mm. For gantry and table angles of 0°, the mean isocenter displacement vectors determined using the three systems were within 0.7 mm and 0.6° of one another. Isocenter rotational offsets measured with the systems were all ≤ 0.5°. For photon and electron beams tested over a period of eight months, the output was verified to remain within 2%, energy variations were within 2%, and the symmetry and flatness were within 1%. The field size and light-radiation coincidence were within 1mm ± 1 mm. For dosimetry reproducibility, the standard deviation was within 0.2% for all tests and all energies, except for photon energy variation which was 0.6%. The total measurement time for all tasks took less than 15 minutes per QA session compared to 40 minutes with our previous procedure, which utilized an individual QA device for each IGSPS. The DQA3 can be used for accurate and efficient Linac and IGSPS daily QA. It shortens QA device setup time, eliminates

  5. Antecedent Factors Affecting Academic Performance of Graduate Students at the Nairobi Evangelical Graduate School of Theology

    ERIC Educational Resources Information Center

    Mbogo, Rosemary Wahu

    2016-01-01

    This paper reports the findings of a Master's level thesis work that was done in 1997 to assess the antecedent factors affecting the academic performance of graduate students at the Nairobi Evangelical School of Theology (N.E.G.S.T.), which is currently Africa International University (AIU). The paper reviews the effect of lack of finance on…

  6. Internal Challenges Affecting Academic Performance of Student-Athletes in Ghanaian Public Universities

    ERIC Educational Resources Information Center

    Apaak, Daniel; Sarpong, Emmanuel Osei

    2015-01-01

    This paper examined internal challenges affecting academic performance of student-athletes in Ghanaian public universities, using a descriptive survey research design. Proportionate random sampling technique was employed to select Three Hundred and Thirty-Two (332) respondents for the study. The instrument used in gathering data for the study was…

  7. ULTRAFINE CARBON PARTICLE (UFCP) INHALATION AFFECTS CARDIOVASCULAR PERFORMANCE IN HYPERTENSIVE RATS (SHR)

    EPA Science Inventory

    Inhaled UfCP affect cardiovascular performance in healthy rats (Harder et al. Inhal Toxicol 2005; 17:29-42) without apparent pulmonary damage. To assess whether geriatric cardiovascular compromised rats are more susceptible to UfCP effects, male adult (6months) and geriatric (13m...

  8. Factors Affecting University Entrants' Performance in High-Stakes Tests: A Multiple Regression Analysis

    ERIC Educational Resources Information Center

    Uy, Chin; Manalo, Ronaldo A.; Cabauatan, Ronaldo R.

    2015-01-01

    In the Philippines, students seeking admission to a university are usually required to meet certain entrance requirements, including passing the entrance examinations with questions on IQ and English, mathematics, and science. This paper aims to determine the factors that affect the performance of entrants into business programmes in high-stakes…

  9. Students Perceptions on Factors That Affect Their Academic Performance: The Case of Great Zimbabwe University (GZU)

    ERIC Educational Resources Information Center

    Mapuranga, Barbra; Musingafi, Maxwell C. C.; Zebron, Shupikai

    2015-01-01

    Some educators argue that entry standards are the most important determinants of successful completion of a university programme; others maintain that non-academic factors must also be considered. In this study we sought to investigate open and distance learning students' perceptions of the factors affecting academic performance and successful…

  10. Motivating Factors that Affect Enrolment and Student Performance in an ODL Engineering Program

    ERIC Educational Resources Information Center

    Dadigamuwa, P. R.; Senanayake, Samans

    2012-01-01

    The present study was carried out to determine the motivating factors for enrolling in an engineering study programme in open and distance learning (ODL) and the factors that affect the students' performance. The study was conducted with two convenient samples of students following distance learning courses in engineering technology, conducted by…

  11. Study of Core Competency Elements and Factors Affecting Performance Efficiency of Government Teachers in Northeastern Thailand

    ERIC Educational Resources Information Center

    Chansirisira, Pacharawit

    2012-01-01

    The research aimed to investigate the core competency elements and the factors affecting the performance efficiency of the civil service teachers in the northeastern region, Thailand. The research procedure consisted of two steps. In the first step, the data were collected using a questionnaire with the reliability (Cronbach's Alpha) of 0.90. The…

  12. The Effect of Device Layout Schemes on RF Performance of Multi-Finger MOSFETs

    NASA Astrophysics Data System (ADS)

    Oh, Yongho; Rieh, Jae-Sung

    In this work, the effect of device dimension variation and metal wiring scheme on the RF performance of MOSFETs based on 0.13-µm RFCMOS technology has been investigated. Two sets of experiments have been carried out. In the first experiment, two types of source metal wiring options, each with various gate poly pitches, have been investigated. The results showed that the extrinsic capacitances (Cegs, Cegd) and parasitic resistances tend to increase with increasing gate poly pitch. Both cutoff frequency (fT) and maximum oscillation frequency (fmax) showed substantial degradation for the larger gate poly pitches. Based on measurement, we propose a simplified model for extrinsic parasitic capacitance as a function of gate poly pitch with different source metal wiring schemes. For the second experiment, the impact of gate metal wiring scheme and the number of gate fingers Nf on the RF performance of MOSFET has been studied. Two different types of gate metal wiring schemes, one with poly layer and the other with M2 layer, are compared. The measurement showed that the capacitance is slightly increased, while gate resistance significantly reduced, with the M2 gate wiring. As a result, fT is slightly degraded but fmax is significantly improved, especially for larger Nf, with the M2 gate wiring. The results in this work provide useful information regarding device dimension and metal wiring scheme for various RF applications of RF CMOS technology.

  13. Residue-free fabrication of high-performance graphene devices by patterned PMMA stencil mask

    SciTech Connect

    Shih, Fu-Yu; Chen, Shao-Yu; Wu, Tsuei-Shin; Wang, Wei-Hua; Liu, Cheng-Hua; Chen, Yang-Fang; Ho, Po-Hsun; Chen, Chun-Wei

    2014-06-15

    Two-dimensional (2D) atomic crystals and their hybrid structures have recently attracted much attention due to their potential applications. The fabrication of metallic contacts or nanostructures on 2D materials is very common and generally achieved by performing electron-beam (e-beam) lithography. However, e-beam lithography is not applicable in certain situations, e.g., cases in which the e-beam resist does not adhere to the substrates or the intrinsic properties of the 2D materials are greatly altered and degraded. Here, we present a residue-free approach for fabricating high-performance graphene devices by patterning a thin film of e-beam resist as a stencil mask. This technique can be generally applied to substrates with varying surface conditions, while causing negligible residues on graphene. The technique also preserves the design flexibility offered by e-beam lithography and therefore allows us to fabricate multi-probe metallic contacts. The graphene field-effect transistors fabricated by this method exhibit smooth surfaces, high mobility, and distinct magnetotransport properties, confirming the advantages and versatility of the presented residue-free technique for the fabrication of devices composed of 2D materials.

  14. Enhanced performance and stability of polymer BHJ photovoltaic devices from dry transfer of PEDOT:PSS.

    PubMed

    Kim, Jung Kyu; Park, Insun; Kim, Wanjung; Wang, Dong Hwan; Choi, Dae-Geun; Choi, Yeong Suk; Park, Jong Hyeok

    2014-07-01

    Polymer solar cells with enhanced initial cell performances and long-term stability were fabricated by performing a simple dry transfer of a hole extraction layer [poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)] onto an indium tin oxide (ITO) substrate. Due to the very flat surface of the polyurethane acrylate/polycarbonate (PUA/PC) film, which was used as a mold and resembled the surface of the original substrate (silicon wafer), the transferred layer had a very smooth surface morphology, resulting in enhancement of the interfacial characteristics. The work function of the PEDOT:PSS layer and the morphology of bulk hetero junction (BHJ) layer were tuned by controlling the position of PSS enrichment in the PEDOT:PSS layer using the dry transfer. The power conversion efficiency of PTB7:PC71 BM BHJ device prepared by the dry transfer was 8.06%, which was significantly higher than that of the spin-cast device (7.32%). By avoiding direct contact between the ITO substrate and the PEDOT:PSS solution in the dry transfer system, etching and diffusion of indium in the ITO substrate were greatly reduced, thereby improving the stability.

  15. [Aerosol deposition and clinical performance verified with a spacer device made in Brazil

    PubMed

    Camargos, P A; Rubim, J A; Simal, C J; Lasmar, L M

    2000-01-01

    OBJECTIVE: To assess the lung deposition pattern of radioaerosol and the clinical performance of a spacer developed and made in Brazil. METHODS: Qualitative - in a patient with cystic fibrosis - and semi-quantitative - in two healthy volunteers - assessment of pulmonary deposition of (99)mtechnetium was done using the Aerogama Medical oxigen driven nebulizer system attached to the spacer and a gama-camera (Siemens, model Orbiter) connected to a microcomputer. In the next step, clinical assessment was carried out in 50 asthmatic children, aged from four months to 13 years old with an acute attack, using conventional doses of albuterol through a metered dose inhaler attached to the spacer device. RESULTS: Qualitative assessment revealed a lung silhouette comparable with those obtained in the inhalation scintigraphy and semiquantitative assessment reveals that 7.5% to 8.0% of the inhaled (99m)technetium reached the volunteerś lungs. Statistically significant differences (p < 0.001) were observed comparing clinical scores at admission with those verified 20 and 40 minutes after albuterol inhalation; conversely, no significance was obtained for scores taken at 60 and 80 minutes. CONCLUSIONS: Although we used an alternative method, the scintigraphic assessment reveals an expected pattern of pulmonary deposition. Similarly, clinical performance in the treatment of an acute attack showed results comparable with those obtained with other spacers devices.

  16. Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance

    NASA Astrophysics Data System (ADS)

    Seif, Johannes Peter; Menda, Deneb; Descoeudres, Antoine; Barraud, Loris; Özdemir, Orhan; Ballif, Christophe; De Wolf, Stefaan

    2016-08-01

    Amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use silicon suboxides as passivation layers—inserted between substrate and (front or rear) contacts—since such layers enable intentionally exacerbated band-offset asymmetry. Investigating all topologically possible passivation layer permutations and focussing on light and dark current-voltage characteristics, we confirm that to avoid fill factor losses, wider-bandgap silicon oxide films (of at least several nanometer thin) should be avoided in hole-collecting contacts. As a consequence, device implementation of such films as window layers—without degraded carrier collection—demands electron collection at the front and hole collection at the rear. Furthermore, at elevated operating temperatures, once possible carrier transport barriers are overcome by thermionic (field) emission, the device performance is mainly dictated by the passivation of its surfaces. In this context, compared to the standard amorphous silicon layers, the wide-bandgap oxide layers applied here passivate remarkably better at these temperatures, which may represent an additional benefit under practical operation conditions.

  17. Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance

    DOE PAGES

    Seif, Johannes Peter; Menda, Deneb; Descoeudres, Antoine; ...

    2016-08-01

    Here, amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use silicon suboxides as passivation layers -- inserted between substrate and (front or rear) contacts -- since such layers enable intentionally exacerbated band-offset asymmetry. Investigating all topologically possible passivation layer permutations and focussing on light and dark current-voltage characteristics, we confirm that to avoid fill factor losses, wider-bandgap silicon oxide films (of at least several nanometer thin) should be avoided in hole-collecting contacts. Asmore » a consequence, device implementation of such films as window layers -- without degraded carrier collection -- demands electron collection at the front and hole collection at the rear. Furthermore, at elevated operating temperatures, once possible carrier transport barriers are overcome by thermionic (field) emission, the device performance is mainly dictated by the passivation of its surfaces. In this context, compared to the standard amorphous silicon layers, the wide-bandgap oxide layers applied here passivate remarkably better at these temperatures, which may represent an additional benefit under practical operation conditions.« less

  18. Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance

    SciTech Connect

    Seif, Johannes Peter; Menda, Deneb; Descoeudres, Antoine; Barraud, Loris; Özdemir, Orhan; Ballif, Christophe; De Wolf, Stefaan

    2016-08-01

    Here, amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use silicon suboxides as passivation layers -- inserted between substrate and (front or rear) contacts -- since such layers enable intentionally exacerbated band-offset asymmetry. Investigating all topologically possible passivation layer permutations and focussing on light and dark current-voltage characteristics, we confirm that to avoid fill factor losses, wider-bandgap silicon oxide films (of at least several nanometer thin) should be avoided in hole-collecting contacts. As a consequence, device implementation of such films as window layers -- without degraded carrier collection -- demands electron collection at the front and hole collection at the rear. Furthermore, at elevated operating temperatures, once possible carrier transport barriers are overcome by thermionic (field) emission, the device performance is mainly dictated by the passivation of its surfaces. In this context, compared to the standard amorphous silicon layers, the wide-bandgap oxide layers applied here passivate remarkably better at these temperatures, which may represent an additional benefit under practical operation conditions.

  19. Device Performance of the Mott Insulator LaVO3 as a Photovoltaic Material

    NASA Astrophysics Data System (ADS)

    Wang, Lingfei; Li, Yongfeng; Bera, Ashok; Ma, Chun; Jin, Feng; Yuan, Kaidi; Yin, Wanjian; David, Adrian; Chen, Wei; Wu, Wenbin; Prellier, Wilfrid; Wei, Suhuai; Wu, Tom

    2015-06-01

    Searching for solar-absorbing materials containing earth-abundant elements with chemical stability is of critical importance for advancing photovoltaic technologies. Mott insulators have been theoretically proposed as potential photovoltaic materials. In this paper, we evaluate their performance in solar cells by exploring the photovoltaic properties of Mott insulator LaVO3 (LVO). LVO films show an indirect band gap of 1.08 eV as well as strong light absorption over a wide wavelength range in the solar spectrum. First-principles calculations on the band structure of LVO further reveal that the d -d transitions within the upper and lower Mott-Hubbard bands and p -d transitions between the O 2 p and V 3 d band contribute to the absorption in visible and ultraviolet ranges, respectively. Transport measurements indicate strong carrier trapping and the formation of polarons in LVO. To utilize the strong light absorption of LVO and to overcome its poor carrier transport, we incorporate it as a light absorber in solar cells in conjunction with carrier transporters and evaluate its device performance. Our complementary experimental and theoretical results on such prototypical solar cells made of Mott-Hubbard transition-metal oxides pave the road for developing light-absorbing materials and photovoltaic devices based on strongly correlated electrons.

  20. User-friendly tools on handheld devices for observer performance study

    NASA Astrophysics Data System (ADS)

    Matsumoto, Takuya; Hara, Takeshi; Shiraishi, Junji; Fukuoka, Daisuke; Abe, Hiroyuki; Matsusako, Masaki; Yamada, Akira; Zhou, Xiangrong; Fujita, Hiroshi

    2012-02-01

    ROC studies require complex procedures to select cases from many data samples, and to set confidence levels in each selected case to generate ROC curves. In some observer performance studies, researchers have to develop software with specific graphical user interface (GUI) to obtain confidence levels from readers. Because ROC studies could be designed for various clinical situations, it is difficult task for preparing software corresponding to every ROC studies. In this work, we have developed software for recording confidence levels during observer studies on tiny personal handheld devices such as iPhone, iPod touch, and iPad. To confirm the functions of our software, three radiologists performed observer studies to detect lung nodules by using public database of chest radiograms published by Japan Society of Radiological Technology. The output in text format conformed to the format for the famous ROC kit from the University of Chicago. Times required for the reading each case was recorded very precisely.

  1. Measuring masticatory performance using a new device and β-carotene in test gummy jelly.

    PubMed

    Nokubi, T; Nokubi, F; Yoshimuta, Y; Ikebe, K; Ono, T; Maeda, Y

    2010-11-01

    Objective methods for evaluating masticatory performance are invaluable for quantitative comparisons between various dental treatments as well as diagnosing masticatory disorder. The purpose of this study was to develop an accurate method for automatically measuring masticatory performance using a new measuring device consisting of light-emitting diodes and a photodiode and test gummy jelly. First, the relationship between six known β-carotene concentrations in aqueous solution and the voltage values exhibited on a photodiode was investigated. Mean voltage obtained by red light incident on the photodiode indicated a significantly high correlation (r=0·999 in a cubic function, P<0·01) with β-carotene concentration in the aqueous solution. Second, to establish the optimal measuring conditions for evaluating masticatory performance, factors influencing mean voltage were investigated, such as water temperature and times for rinsing the gummy jelly and dissolving β-carotene from the jelly. A stable mean voltage was obtained by measuring under the following conditions: rinsing water temperature, 35°C; rinsing time, 30s; water dissolving temperature, 35°C; dissolving time, 10s. Finally, the relationship between seven surface area values of divided gummy jelly and β-carotene concentrations dissolved from the divided jellies was investigated. The increase in surface area of divided test gummy jelly particles was accurately calculated (r=0·992, P<0·001) from mean voltage on the photodiode to change with β-carotene concentration dissolved from the jelly surface. This new method using test gummy jelly and an automatic measuring device appears useful for precisely evaluating masticatory performance.

  2. Predicting nitrogen loading with land-cover composition: how can watershed size affect model performance?

    PubMed

    Zhang, Tao; Yang, Xiaojun

    2013-01-01

    Watershed-wide land-cover proportions can be used to predict the in-stream non-point source pollutant loadings through regression modeling. However, the model performance can vary greatly across different study sites and among various watersheds. Existing literature has shown that this type of regression modeling tends to perform better for large watersheds than for small ones, and that such a performance variation has been largely linked with different interwatershed landscape heterogeneity levels. The purpose of this study is to further examine the previously mentioned empirical observation based on a set of watersheds in the northern part of Georgia (USA) to explore the underlying causes of the variation in model performance. Through the combined use of the neutral landscape modeling approach and a spatially explicit nutrient loading model, we tested whether the regression model performance variation over the watershed groups ranging in size is due to the different watershed landscape heterogeneity levels. We adopted three neutral landscape modeling criteria that were tied with different similarity levels in watershed landscape properties and used the nutrient loading model to estimate the nitrogen loads for these neutral watersheds. Then we compared the regression model performance for the real and neutral landscape scenarios, respectively. We found that watershed size can affect the regression model performance both directly and indirectly. Along with the indirect effect through interwatershed heterogeneity, watershed size can directly affect the model performance over the watersheds varying in size. We also found that the regression model performance can be more significantly affected by other physiographic properties shaping nitrogen delivery effectiveness than the watershed land-cover heterogeneity. This study contrasts with many existing studies because it goes beyond hypothesis formulation based on empirical observations and into hypothesis testing to

  3. Impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and device performance of Ge fin field-effect transistors

    NASA Astrophysics Data System (ADS)

    Mizubayashi, Wataru; Noda, Shuichi; Ishikawa, Yuki; Nishi, Takashi; Kikuchi, Akio; Ota, Hiroyuki; Su, Ping-Hsun; Li, Yiming; Samukawa, Seiji; Endo, Kazuhiko

    2017-02-01

    We investigated the impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and the device performance of Ge fin field-effect transistors (Ge FinFETs). UV light irradiation during etching affected the shape of the Ge fin and the surface roughness of the Ge fin sidewall. A vertical and smooth Ge fin could be fabricated by neutral beam etching without UV light irradiation. The performances of Ge FinFETs fabricated by neutral beam etching were markedly improved as compared to those of Ge FinFETs fabricated by inductively coupled plasma etching, in which the UV light has an impact.

  4. Universal and culture-specific factors in the recognition and performance of musical affect expressions.

    PubMed

    Laukka, Petri; Eerola, Tuomas; Thingujam, Nutankumar S; Yamasaki, Teruo; Beller, Grégory

    2013-06-01

    We present a cross-cultural study on the performance and perception of affective expression in music. Professional bowed-string musicians from different musical traditions (Swedish folk music, Hindustani classical music, Japanese traditional music, and Western classical music) were instructed to perform short pieces of music to convey 11 emotions and related states to listeners. All musical stimuli were judged by Swedish, Indian, and Japanese participants in a balanced design, and a variety of acoustic and musical cues were extracted. Results first showed that the musicians' expressive intentions could be recognized with accuracy above chance both within and across musical cultures, but communication was, in general, more accurate for culturally familiar versus unfamiliar music, and for basic emotions versus nonbasic affective states. We further used a lens-model approach to describe the relations between the strategies that musicians use to convey various expressions and listeners' perceptions of the affective content of the music. Many acoustic and musical cues were similarly correlated with both the musicians' expressive intentions and the listeners' affective judgments across musical cultures, but the match between musicians' and listeners' uses of cues was better in within-cultural versus cross-cultural conditions. We conclude that affective expression in music may depend on a combination of universal and culture-specific factors.

  5. A Quality Improvement Study on Avoidable Stressors and Countermeasures Affecting Surgical Motor Performance and Learning

    PubMed Central

    Conrad, Claudius; Konuk, Yusuf; Werner, Paul D.; Cao, Caroline G.; Warshaw, Andrew L.; Rattner, David W.; Stangenberg, Lars; Ott, Harald C.; Jones, Daniel B.; Miller, Diane L; Gee, Denise W.

    2012-01-01

    OBJECTIVE To explore how the two most important components of surgical performance - speed and accuracy - are influenced by different forms of stress and what the impact of music on these factors is. SUMMARY BACKGROUND DATA Based on a recently published pilot study on surgical experts, we designed an experiment examining the effects of auditory stress, mental stress, and music on surgical performance and learning, and then correlated the data psychometric measures to the role of music in a novice surgeon’s life. METHODS 31 surgeons were recruited for a crossover study. Surgeons were randomized to four simple standardized tasks to be performed on the Surgical SIM VR laparoscopic simulator, allowing exact tracking of speed and accuracy. Tasks were performed under a variety of conditions, including silence, dichotic music (auditory stress), defined classical music (auditory relaxation), and mental loading (mental arithmetic tasks). Tasks were performed twice to test for memory consolidation and to accommodate for baseline variability. Performance was correlated to the Brief Musical Experience Questionnaire (MEQ). RESULTS Mental loading influences performance with respect to accuracy, speed, and recall more negatively than does auditory stress. Defined classical music might lead to minimally worse performance initially, but leads to significantly improved memory consolidation. Furthermore, psychologic testing of the volunteers suggests that surgeons with greater musical commitment, measured by the MEQ, perform worse under the mental loading condition. CONCLUSION Mental distraction and auditory stress negatively affect specific components of surgical learning and performance. If used appropriately, classical music may positively affect surgical memory consolidation. It also may be possible to predict surgeons’ performance and learning under stress through psychological tests on the role of music in a surgeon’s life. Further investigation is necessary to determine

  6. Development of Cutting and Suction Device with Twist Blade Screw for Minimally Invasive Surgery: Evaluation of Suction Performance

    PubMed Central

    Fujii, Yusuke; Suzuki, Takashi; Tamura, Manabu; Muragaki, Yoshihiro; Iseki, Hiroshi

    2015-01-01

    In this study, we aim to develop a narrow-diameter and long-bore device for minimally invasive surgery that achieves the simultaneous cutting and suction of body tissue such as the diseased part of an organ. In this paper, we propose a screw made of a thin metal plate, and we developed a prototype device using this screw. For smooth operation, the suction performance must be superior to the cutting performance. Therefore, we performed experiments and evaluated the suction performance of the developed device assuming the crushed tissue pieces correspond to a highly viscous fluid. From the results, we confirmed that the suction volume is almost proportional to the rotation speed of the screw in the low speed range, and the device has an upper limit of suction volume at a certain rotation speed. Considering practical use, its proportional speed range is suitable for the device controllability of cutting and suction volume, and the size of the device tip needs to be 1 mm or more. Based on these conditions, we are planning to examine the shape of the cutting edge for realizing efficient cutting and suction and we will complete the device. PMID:26132592

  7. Performance and sleepiness during a 24 h wake in constant conditions are affected by diet.

    PubMed

    Lowden, Arne; Holmbäck, Ulf; Akerstedt, Torbjörn; Forslund, Jeanette; Lennernäs, Maria; Forslund, Anders

    2004-02-01

    This study investigated the effects of high-carbohydrate (HC) and high-fat (HF) diet on cognitive performance, and subjective and objective sleepiness. Seven male participants were kept awake for 24 h in a metabolic ward. Meals were given every 4h and cognitive performance and sleepiness ratings were assessed hourly. The Karolinska Drowsiness Test (KDT, EEG derived) was performed twice after meal. Performance in simple reaction time showed a significant interaction of diet and the post-prandial period, a slower reaction time was observed for the HC-diet 3.5 h after meal intake. Diet did not affect EEG measures but a general post-prandial increase of objective sleepiness was observed 3.5h after meal servings. The HC-diet was significantly associated with an increase of subjective sleepiness. The study demonstrated that the HC-diet caused larger oscillation in performance and increased sleepiness as compared to HF-diet throughout day and night.

  8. Human resources management and firm performance: The differential role of managerial affective and continuance commitment.

    PubMed

    Gong, Yaping; Law, Kenneth S; Chang, Song; Xin, Katherine R

    2009-01-01

    In this study, the authors developed a dual-concern (i.e., maintenance and performance) model of human resources (HR) management. The authors identified commonly examined HR practices that apply to the middle manager level and classified them into the maintenance- and performance-oriented HR subsystems. The authors found support for the 2-factor model on the basis of responses from 2,148 managers from 463 firms operating in China. Regression results indicate that the performance-oriented HR subsystems had a positive relationship with firm performance and that the relationship was mediated by middle managers' affective commitment to the firm. The maintenance-oriented HR subsystems had a positive relationship with middle managers' continuance commitment but not with their affective commitment and firm performance. This study contributes to the understanding of how HR practices relate to firm performance and offers an improved test of the argument that valuable and firm-specific HR provide a source of competitive advantage. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

  9. Centrality and charisma: comparing how leader networks and attributions affect team performance.

    PubMed

    Balkundi, Prasad; Kilduff, Martin; Harrison, David A

    2011-11-01

    When leaders interact in teams with their subordinates, they build social capital that can have positive effects on team performance. Does this social capital affect team performance because subordinates come to see the leader as charismatic? We answered this question by examining 2 models. First, we tested the charisma-to-centrality model according to which the leader's charisma facilitates the occupation of a central position in the informal advice network. From this central position, the leader positively influences team performance. Second, we examined the centrality-to-charisma model according to which charisma is attributed to those leaders who are socially active in terms of giving and receiving advice. Attributed charisma facilitates increased team performance. We tested these 2 models in 2 different studies. In the first study, based on time-separated, multisource data emanating from members of 56 work teams, we found support for the centrality-to-charisma model. Formal leaders who were central within team advice networks were seen as charismatic by subordinates, and this charisma was associated with high team performance. To clarify how leader network centrality affected the emergence of charismatic leadership, we designed Study 2 in which, for 79 student teams, we measured leader networking activity and leader charisma at 2 different points in time and related these variables to team performance measured at a third point in time. On the basis of this temporally separated data set, we again found support for the centrality-to-charisma model.

  10. Design Procedure and Fabrication of Reproducible Silicon Vernier Devices for High-Performance Refractive Index Sensing

    PubMed Central

    Troia, Benedetto; Khokhar, Ali Z.; Nedeljkovic, Milos; Reynolds, Scott A.; Hu, Youfang; Mashanovich, Goran Z.; Passaro, Vittorio M. N.

    2015-01-01

    In this paper, we propose a generalized procedure for the design of integrated Vernier devices for high performance chemical and biochemical sensing. In particular, we demonstrate the accurate control of the most critical design and fabrication parameters of silicon-on-insulator cascade-coupled racetrack resonators operating in the second regime of the Vernier effect, around 1.55 μm. The experimental implementation of our design strategies has allowed a rigorous and reliable investigation of the influence of racetrack resonator and directional coupler dimensions as well as of waveguide process variability on the operation of Vernier devices. Figures of merit of our Vernier architectures have been measured experimentally, evidencing a high reproducibility and a very good agreement with the theoretical predictions, as also confirmed by relative errors even lower than 1%. Finally, a Vernier gain as high as 30.3, average insertion loss of 2.1 dB and extinction ratio up to 30 dB have been achieved. PMID:26067193

  11. A new device for performing reference point indentation without a reference probe

    NASA Astrophysics Data System (ADS)

    Bridges, Daniel; Randall, Connor; Hansma, Paul K.

    2012-04-01

    Here we describe a novel, hand-held reference point indentation (RPI), instrument that is designed for clinical measurements of bone material properties in living patients. This instrument differs from previous RPI instruments in that it requires neither a reference probe nor removal of the periosteum that covers the bone, thus significantly simplifying its use in patient testing. After describing the instrument, we discuss five guidelines for optimal and reproducible results. These are: (1) the angle between the normal to the surface and the axis of the instrument should be less than 10°, (2) the compression of the main spring to trigger the device must be performed slowly (>1 s), (3) the probe tip should be sharper than 10 μm; however, a normalized parameter with a calibration phantom can correct for dull tips up to a 100 μm radius, (4) the ambient room temperature should be between 4 °C and 37 °C, and (5) the effective mass of the bone or material under test must exceed 1 kg, or if under 1 kg, the specimen should be securely anchored in a fixation device with sufficient mass (which is not a requirement of previous RPI instruments). Our experience is that a person can be trained with these guidelines in about 5 min and thereafter obtain accurate and reproducible results. The portability, ease of use, and minimal training make this instrument suitable to measure bone material properties in a clinical setting.

  12. Design Procedure and Fabrication of Reproducible Silicon Vernier Devices for High-Performance Refractive Index Sensing.

    PubMed

    Troia, Benedetto; Khokhar, Ali Z; Nedeljkovic, Milos; Reynolds, Scott A; Hu, Youfang; Mashanovich, Goran Z; Passaro, Vittorio M N

    2015-06-10

    In this paper, we propose a generalized procedure for the design of integrated Vernier devices for high performance chemical and biochemical sensing. In particular, we demonstrate the accurate control of the most critical design and fabrication parameters of silicon-on-insulator cascade-coupled racetrack resonators operating in the second regime of the Vernier effect, around 1.55 μm. The experimental implementation of our design strategies has allowed a rigorous and reliable investigation of the influence of racetrack resonator and directional coupler dimensions as well as of waveguide process variability on the operation of Vernier devices. Figures of merit of our Vernier architectures have been measured experimentally, evidencing a high reproducibility and a very good agreement with the theoretical predictions, as also confirmed by relative errors even lower than 1%. Finally, a Vernier gain as high as 30.3, average insertion loss of 2.1 dB and extinction ratio up to 30 dB have been achieved.

  13. The effects of heavy ion radiation on digital micromirror device performance

    NASA Astrophysics Data System (ADS)

    Travinsky, Anton; Vorobiev, Dmitry; Raisanen, Alan D.; Pellish, Jonathan; Ninkov, Zoran; Robberto, Massimo; Heap, Sara

    2016-02-01

    There is a need for a space-suitable solution to the selection of targets to be observed in astronomical multiobject spectrometers (MOS). A few digital micromirror device (DMD) - based prototype MOS have been developed for use at ground observatories, However their main use will come in deploying a space based mission. The question of DMD performance under in-orbit radiation remains unanswered. DMDs were tested under accelerated heavy-ion radiation (with the control electronics shielded from radiation), with a focus on detection of single-event effects (SEEs) including latch-up events. Testing showed that DMDs are sensitive to non-destructive ion-induced state changes; however, all SEEs were cleared with a soft reset (that is, sending a new pattern to the device). The DMDs did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. This suggests that the SSE rate burden will be manageable for a DMD-based instrument when exposed to solar particle fluxes and cosmic rays on orbit.

  14. Performance prediction of four-contact vertical Hall-devices using a conformal mapping technique

    NASA Astrophysics Data System (ADS)

    Yang, Huang; Yue, Xu; Yufeng, Guo

    2015-12-01

    Instead of the conventional design with five contacts in the sensor active area, innovative vertical Hall devices (VHDs) with four contacts and six contacts are asymmetrical in structural design but symmetrical in the current flow that can be well fit for the spinning current technique for offset elimination. In this article, a conformal mapping calculation method is used to predict the performance of asymmetrical VHD embedded in a deep n-well with four contacts. Furthermore, to make the calculation more accurate, the junction field effect is also involved into the conformal mapping method. The error between calculated and simulated results is less than 5% for the current-related sensitivity, and approximately 13% for the voltage-related sensitivity. This proves that such calculations can be used to predict the optimal structure of the vertical Hall-devices. Project supported by the Natural Science Foundation of Jiangsu Province, China (Nos. BK20131379, BK20141431) and the Graduate Research and Innovation Projects of Jiangsu Province (No. SJLX_0373).

  15. A new device for performing reference point indentation without a reference probe

    PubMed Central

    Bridges, Daniel; Randall, Connor; Hansma, Paul K.

    2012-01-01

    Here we describe a novel, hand-held reference point indentation (RPI), instrument that is designed for clinical measurements of bone material properties in living patients. This instrument differs from previous RPI instruments in that it requires neither a reference probe nor removal of the periosteum that covers the bone, thus significantly simplifying its use in patient testing. After describing the instrument, we discuss five guidelines for optimal and reproducible results. These are: (1) the angle between the normal to the surface and the axis of the instrument should be less than 10°, (2) the compression of the main spring to trigger the device must be performed slowly (>1 s), (3) the probe tip should be sharper than 10 μm; however, a normalized parameter with a calibration phantom can correct for dull tips up to a 100 μm radius, (4) the ambient room temperature should be between 4 °C and 37 °C, and (5) the effective mass of the bone or material under test must exceed 1 kg, or if under 1 kg, the specimen should be securely anchored in a fixation device with sufficient mass (which is not a requirement of previous RPI instruments). Our experience is that a person can be trained with these guidelines in about 5 min and thereafter obtain accurate and reproducible results. The portability, ease of use, and minimal training make this instrument suitable to measure bone material properties in a clinical setting. PMID:22559552

  16. Preliminary performance assessment of biotoxin detection for UWS applications using a MicroChemLab device.

    SciTech Connect

    VanderNoot, Victoria A.; Haroldsen, Brent L.; Renzi, Ronald F.; Shokair, Isaac R.

    2010-03-01

    In a multiyear research agreement with Tenix Investments Pty. Ltd., Sandia has been developing field deployable technologies for detection of biotoxins in water supply systems. The unattended water sensor or UWS employs microfluidic chip based gel electrophoresis for monitoring biological analytes in a small integrated sensor platform. This instrument collects, prepares, and analyzes water samples in an automated manner. Sample analysis is done using the {mu}ChemLab{trademark} analysis module. This report uses analysis results of two datasets collected using the UWS to estimate performance of the device. The first dataset is made up of samples containing ricin at varying concentrations and is used for assessing instrument response and detection probability. The second dataset is comprised of analyses of water samples collected at a water utility which are used to assess the false positive probability. The analyses of the two sets are used to estimate the Receiver Operating Characteristic or ROC curves for the device at one set of operational and detection algorithm parameters. For these parameters and based on a statistical estimate, the ricin probability of detection is about 0.9 at a concentration of 5 nM for a false positive probability of 1 x 10{sup -6}.

  17. A new device for performing reference point indentation without a reference probe.

    PubMed

    Bridges, Daniel; Randall, Connor; Hansma, Paul K

    2012-04-01

    Here we describe a novel, hand-held reference point indentation (RPI), instrument that is designed for clinical measurements of bone material properties in living patients. This instrument differs from previous RPI instruments in that it requires neither a reference probe nor removal of the periosteum that covers the bone, thus significantly simplifying its use in patient testing. After describing the instrument, we discuss five guidelines for optimal and reproducible results. These are: (1) the angle between the normal to the surface and the axis of the instrument should be less than 10°, (2) the compression of the main spring to trigger the device must be performed slowly (>1 s), (3) the probe tip should be sharper than 10 μm; however, a normalized parameter with a calibration phantom can correct for dull tips up to a 100 μm radius, (4) the ambient room temperature should be between 4 °C and 37 °C, and (5) the effective mass of the bone or material under test must exceed 1 kg, or if under 1 kg, the specimen should be securely anchored in a fixation device with sufficient mass (which is not a requirement of previous RPI instruments). Our experience is that a person can be trained with these guidelines in about 5 min and thereafter obtain accurate and reproducible results. The portability, ease of use, and minimal training make this instrument suitable to measure bone material properties in a clinical setting.

  18. Molecular orientation, thermal behavior and density of electron and hole transport layers and the implication on device performance for OLEDs

    NASA Astrophysics Data System (ADS)

    Kearns, Kenneth L.; Na, Hong-Yeop; Froese, Robert D.; Mukhopadhyay, Sukrit; Woodward, Hunter; Welsh, Dean; De Vries, Timothy; Devore, David; Trefonas, Peter; Hong, Liang

    2014-10-01

    Recent progress has shown that molecular orientation in vapor-deposited glasses can affect device performance. The deposition process can result in films where the molecular axis of the glass material is preferentially ordered to lie parallel to the plane of the substrate. Here, materials made within Dow's Electronic Materials business showed enhanced performance when the orientation of the molecules, as measured by variable angle spectroscopic ellipsometry, was oriented in a more parallel fashion as compared to other materials. For one material, the anisotropic packing was observed in the as-deposited glass and was isotropic for solution-cast and annealed films. In addition, the density of an as-deposited N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine (NPD) film was 0.8% greater than what was realized from slowly cooling the supercooled liquid. This enhanced density indicated that vapor-deposited molecules were packing more closely in addition to being anisotropic. Finally, upon heating the NPD film into the supercooled liquid state, both the density and anisotropic packing of the as-deposited glass was lost.

  19. Experimental evaluation of cooling efficiency of the high performance cooling device

    NASA Astrophysics Data System (ADS)

    Nemec, Patrik; Malcho, Milan

    2016-06-01

    This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

  20. Long-term performance of visual and electronic identification devices in dairy goats.

    PubMed

    Carné, S; Caja, G; Ghirardi, J J; Salama, A A K

    2009-04-01

    Dairy goat kids born during a 3-yr period (n = 97) and their mothers (n = 29) were used for a long-term evaluation of the performance of 9 types of identification (ID) devices. Kids wore multiple ID devices: visual ear tags (V1, tip-tag, n = 47; V2, official, n = 50), electronic ear tags (E1, button-button, n = 46; E2, flag-button, n = 46), electronic rumen boluses (B1, mini-bolus 14 g, n = 92; B2, mini-bolus 20 g, n = 28; B3, standard bolus 75 g, n = 34) and glass-encapsulated transponders injected in the forefeet (T1, 15 mm, n = 75; T2, 12 mm, n = 100). Visual ear tags were applied at birth and removed in yearlings, whereas electronic ear tags were applied after bolusing with B1 (6.7 kg BW and 30 d, on average); B2 were administered in the event of a B1 loss, and B3 in case of a B2 loss and in goat does. At d 60 of age, kids were allocated into 2 groups to evaluate the effects of rearing system on ID. Treatments were: weaned (n = 46), and not weaned (n = 46) where kids suckled a milk substitute until d 150. Readability of ID devices (read/readable x 100) was monitored from 1 to 3 yr of age, depending on device and year of birth. Long-term readability was analyzed using a nonparametric survival analysis. A total of 3.3% infections and 6.5% tissue reactions were reported for electronic ear tags, but ears were fully healed in yearlings. Weaning numerically reduced B1 losses at d 150 (weaned, 84.8% vs. not weaned, 73.3%). Readability of visual ear tags in yearlings (V1, 82.9%; V2, 94.0%) was lower than for electronic ear tags (E1 and E2, 100%). Mini-bolus readability in yearlings did not differ by type (B1, 71.4%; B2, 84.6%) or with visual ear tags. No effect of inject type was reported (T1, 92.0%; T2, 96.0%). Survival analysis after yr 3 gave the greatest readability value for E1 (100%), which did not differ from B3 (96.8%). The lowest readability was estimated for B1 (66.3%), followed by E2 (79.8%), B2 (81.4%), and T1 (90.4%). In conclusion, button

  1. Using representations in geometry: a model of students' cognitive and affective performance

    NASA Astrophysics Data System (ADS)

    Panaoura, Areti

    2014-05-01

    Self-efficacy beliefs in mathematics, as a dimension of the affective domain, are related with students' performance on solving tasks and mainly on overcoming cognitive obstacles. The present study investigated the interrelations of cognitive performance on geometry and young students' self-efficacy beliefs about using representations for solving geometrical tasks. The emphasis was on confirming a theoretical model for the primary-school and secondary-school students and identifying the differences and similarities for the two ages. A quantitative study was developed and data were collected from 1086 students in Grades 5-8. Confirmatory factor analysis affirmed the existence of a coherent model of affective dimensions about the use of representations for understanding the geometrical concepts, which becomes more stable across the educational levels.

  2. Evaluation of left ventricular assist device performance and hydraulic force in a complete mock circulation loop.

    PubMed

    Timms, Daniel; Hayne, Mark; Tan, Andy; Pearcy, Mark

    2005-07-01

    Centrifugal pump performance characteristics are vital in determining the ability of a prototype left ventricular assist device (LVAD) to meet the physiological circulation requirements of the cardiovascular system. These characteristics influence the static hydraulic forces encountered by the pump impeller, which determine the required load stiffness of suspension type bearings to minimize impeller touchdown. Performance investigations were conducted on an LVAD design while characterizing the impeller static hydraulic forces of various impeller/volute configurations. The pumps were inserted into a complete systemic and pulmonary mock circulation rig configured to provide suitable nonpulsatile or simulated pulsatile left heart failure environments. The single volute and closed shroud impeller configuration exhibited lowest radial (0.01 N) and axial (3 N) force at nonpulsatile design flow conditions, respectively. Normal hemodynamic conditions of 5.1 L/min at 94 mm Hg were re-established upon inserting the device into the left heart failure environment, where the pump operated along the nonpulsatile characteristic curve for 2200 rpm. The operational limits on this curve were dictated by the required pressure differential across the pump during systolic and diastolic periods. The reduction of left atrial pressure (25 to 8 mm Hg) indicated the alleviation of pulmonary congestion. The ability for the LVAD to support circulation in a left heart failure environment was successfully demonstrated in the mock circulation loop. The impeller hydraulic force characteristics attained will aid the bearing designer to select the best volute and impeller configuration to minimize impeller touchdown in magnetic, hydrodynamic or mechanical type bearing applications.

  3. Enabling Earth-Abundant Pyrite (FeS2) Semiconductor Nanostructures for High Performance Photovoltaic Devices

    SciTech Connect

    Jin, Song

    2014-11-18

    This project seeks to develop nanostructures of iron pyrite, an earth-abundant semiconductor, to enable their applications in high-performance photovoltaic (PV) devices. Growth of high purity iron pyrite nanostructures (nanowires, nanorods, and nanoplates), as well as iron pyrite thin films and single crystals, has been developed and their structures characterized. These structures have been fundamentally investigated to understand the origin of the low solar energy conversion efficiency of iron pyrite and various passivation strategies and doping approaches have been explored in order to improve it. By taking advantage of the high surface-to-bulk ratio in nanostructures and effective electrolyte gating, we fully characterized both the surface inversion and bulk electrical transport properties for the first time through electrolyte-gated Hall measurements of pyrite nanoplate devices and show that pyrite is n-type in the bulk and p-type near the surface due to strong inversion, which has important consequences to using nanocrystalline pyrite for efficient solar energy conversion. Furthermore, through a comprehensive investigation on n-type iron pyrite single crystals, we found the ionization of high-density bulk deep donor states, likely resulting from bulk sulfur vacancies, creates a non-constant charge distribution and a very narrow surface space charge region that limits the total barrier height, thus satisfactorily explains the limited photovoltage and poor photoconversion efficiency of iron pyrite single crystals. These findings suggest new ideas on how to improve single crystal pyrite and nanocrystalline or polycrystalline pyrite films to enable them for high performance solar applications.

  4. Effects of nanostructure geometry on polymer chain alignment and device performance in nanoimprinted polymer solar cell

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Mielczarek, Kamil; Zakhidov, Anvar; Hu, Walter

    2013-03-01

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. This article demonstrates our recent studies on the nanostructure geometry effects on the nanoimprint induced poly(3 hexylthiophene-2,5-diyl) (P3HT) chain alignment and photovoltaic performance. Out-of-plane and in-plane grazing incident X-ray diffractions are employed to characterize the chain orientations in P3HT nanogratings with different widths and heights. It is found that nanoimprint procedure changes the initial edge-on alignment in non-imprinted P3HT thin film to a vertical orientation which favors the hole transport, with an organization height H≥ 170 nm and width in the range of 60 nm<= W< 210 nm. Samples with better aligned molecules lead to a larger crystallite sizes as well. Imprinted P3HT/[6,6]-penyl-C61-butyric-acid-methyl-ester (PCBM) solar cells show an increase in power conversion efficiency (PCE) with the decrease of nanostructure width, and with the increase of height and junction area. Devices with the highest PCE are made by the fully aligned and highest P3HT nanostructures (width w= 60 nm, height h= 170 nm), allowing for the most efficient charge separation, transport and light absorption. We believe this work will contribute to the optimal geometry design of nanoimprinted polymer solar cells.

  5. Force production during squats performed with a rotational resistance device under stable versus unstable conditions

    PubMed Central

    Moras, Gerard; Vázquez-Guerrero, Jairo

    2015-01-01

    [Purpose] Force production during a squat action on a rotational resistance device (RRD) under stable and unstable conditions. [Subjects and Methods] Twenty-one healthy males were asked to perform six sets of six repetitions of squats on an RRD on either stable or unstable surfaces. The stable and unstable sets were performed on different days. Muscular outputs were obtained from a linear encoder and a strain gauge fixed to a vest. [Results] Overall, the results showed no significant differences for any of the dependent variables across exercise modes. Forcemean outputs were higher in the concentric phase than in the eccentric phase for each condition, but there were no differences in velocity, time or displacement. The forcepeak was similar in the eccentric and concentric phases of movement under both stable and unstable conditions. There were no significant differences in forcemean between sets per condition or between conditions. [Conclusion] These results suggest that performing squats with a RRD achieves similar forcemean and forcepeak under stable and unstable conditions. The forcepeak produced is also similar in concentric and eccentric phases. PMID:26696707

  6. Evaluating the Performance of the NASA LaRC CMF Motion Base Safety Devices

    NASA Technical Reports Server (NTRS)

    Gupton, Lawrence E.; Bryant, Richard B., Jr.; Carrelli, David J.

    2006-01-01

    This paper describes the initial measured performance results of the previously documented NASA Langley Research Center (LaRC) Cockpit Motion Facility (CMF) motion base hardware safety devices. These safety systems are required to prevent excessive accelerations that could injure personnel and damage simulator cockpits or the motion base structure. Excessive accelerations may be caused by erroneous commands or hardware failures driving an actuator to the end of its travel at high velocity, stepping a servo valve, or instantly reversing servo direction. Such commands may result from single order failures of electrical or hydraulic components within the control system itself, or from aggressive or improper cueing commands from the host simulation computer. The safety systems must mitigate these high acceleration events while minimizing the negative performance impacts. The system accomplishes this by controlling the rate of change of valve signals to limit excessive commanded accelerations. It also aids hydraulic cushion performance by limiting valve command authority as the actuator approaches its end of travel. The design takes advantage of inherent motion base hydraulic characteristics to implement all safety features using hardware only solutions.

  7. Tadpole swimming performance and activity affected by acute exposure to sublethal levels of carbaryl

    USGS Publications Warehouse

    Bridges, C.M.

    1997-01-01

    General activity and swimming performance (i.e., sprint speed and distance) of plains leopard frog tadpoles (Rana blairi) were examined after acute exposure to three sublethal concentrations of carbaryl (3.5, 5.0, and 7.2 mg/L). Both swimming performance and spontaneous swimming activity are important for carrying out life history functions (e.g., growth and development) and for escaping from predators. Measured tadpole activity diminished by nearly 90% at 3.5 mg/L carbaryl and completely ceased at 7.2 mg/L. Sprint speed and sprint distance also decreased significantly following exposure. Carbaryl affected both swimming performance and activity after just 24 h, suggesting that 24 h may be an adequate length of exposure to determine behavioral effects on tadpoles. Slight recovery of activity levels was noted at 24 and 48 h post-exposure; no recovery of swimming performance was observed. Reduction in activity and swimming performance may result in increased predation rates and, because activity is closely associated with feeding, may result in slowed growth leading to a failure to emerge before pond drying or an indirect reduction in adult fitness. Acute exposure to sublethal toxicants such as carbaryl may not only affect immediate survival of tadpoles but also impact critical life history functions and generate changes at the local population level.

  8. Thought waves remotely affect the performance (output voltage) of photoelectric cells

    NASA Astrophysics Data System (ADS)

    Cao, Dayong; Cao, Daqing

    2012-02-01

    In our experiments, thought waves have been shown to be capable of changing (affecting) the output voltage of photovoltaic cells located from as far away as 1-3 meters. There are no wires between brain and photoelectric cell and so it is presumed only the thought waves act on the photoelectric cell. In continual rotations, the experiments tested different solar cells, measuring devices and lamps, and the experiments were done in different labs. The first experiment was conducted on Oct 2002. Tests are ongoing. Conclusions and assumptions include: 1) the slow thought wave has the energy of space-time as defined by C1.00007: The mass, energy, space and time systemic theory- MEST. Every process releases a field effect electrical vibration which be transmitted and focussed in particular paths; 2) the thought wave has the information of the order of tester; 3) the brain (with the physical system of MEST) and consciousness (with the spirit system of the mind, consciousness, emotion and desire-MECD) can produce the information (a part of them as the Genetic code); 4) through some algorithms such as ACO Ant Colony Optimization and EA Evolutionary Algorithm (or genetic algorithm) working in RAM, human can optimize the information. This Optimizational function is the intelligence; 5) In our experiments, not only can thought waves affect the voltage of the output photoelectric signals by its energy, but they can also selectively increase or decrease those photoelectric currents through remote consciousness interface and a conscious-brain information technology.

  9. The fat of the matter: how dietary fatty acids can affect exercise performance.

    PubMed

    Pierce, Barbara J; McWilliams, Scott R

    2014-11-01

    Fatty-acid composition of fat stores affects exercise performance in a variety of vertebrates although few such studies focus on flying vertebrates such as migratory birds, which are exceptional exercisers. We first discuss the natural variation in quality of fat available in natural foods eaten by migratory birds and their behavioral preferences for specific fatty acids in these foods. We then outline three proposed hypotheses for how dietary fatty acids can affect exercise performance, and some of the evidence to date that pertains to these hypotheses with special emphasis on the exercise performance of migratory birds. In theory, selectively feeding on certain long-chain unsaturated fatty acids may be advantageous because (1) such fatty acids may be metabolized more quickly and may stimulate key facets of aerobic metabolism (fuel hypothesis); (2) such fatty acids may affect composition and key functions of lipid-rich cell membranes (membrane hypothesis); and (3) such fatty acids may directly act as signaling molecules (signal hypothesis). Testing these hypotheses requires cleverly designed experiments that can distinguish between them by demonstrating that certain fatty acids stimulate oxidative capacity, including gene expression and activity of key oxidative enzymes, and that this stimulation changes during exercise.

  10. Performance evaluation of a high power DC-DC boost converter for PV applications using SiC power devices

    NASA Astrophysics Data System (ADS)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2016-09-01

    The development of Wide band gap (WBG) power devices has been attracted by many commercial companies to be available in the market because of their enormous advantages over the traditional Si power devices. An example of WBG material is SiC, which offers a number of advantages over Si material. For example, SiC has the ability of blocking higher voltages, reducing switching and conduction losses and supports high switching frequency. Consequently, SiC power devices have become the affordable choice for high frequency and power application. The goal of this paper is to study the performance of 4.5 kW, 200 kHz, 600V DC-DC boost converter operating in continuous conduction mode (CCM) for PV applications. The switching behavior and turn on and turn off losses of different switching power devices such as SiC MOSFET, SiC normally ON JFET and Si MOSFET are investigated and analyzed. Moreover, a detailed comparison is provided to show the overall efficiency of the DC-DC boost converter with different switching power devices. It is found that the efficiency of SiC power switching devices are higher than the efficiency of Si-based switching devices due to low switching and conduction losses when operating at high frequencies. According to the result, the performance of SiC switching power devices dominate the conventional Si power devices in terms of low losses, high efficiency and high power density. Accordingly, SiC power switching devices are more appropriate for PV applications where a converter of smaller size with high efficiency, and cost effective is required.

  11. Disodium edetate as a promising interfacial material for inverted organic solar cells and the device performance optimization.

    PubMed

    Li, Xiaodong; Zhang, Wenjun; Wang, Xueyan; Gao, Feng; Fang, Junfeng

    2014-12-10

    Disodium edetate (EDTA-Na), a popular hexadentate ligand in analytical chemistry, was successfully introduced in organic solar cells (OSCs) as cathode interfacial layer. The inverted OSCs with EDTA-Na showed superior performance both in power conversion efficiency and devices stability compared with conventional devices. Interestingly, we found that the performance of devices with EDTA-Na could be optimized through external bias treatment. After optimization, the efficiency of inverted OSCs with device structure of ITO/EDTA-Na/polymer thieno[3,4-b]thiophene/benzodithiophene (PTB7):PC71BM/MoO3/Al was significantly increased to 8.33% from an initial value of 6.75%. This work introduces a new class of interlayer materials, small molecule electrolytes, for organic solar cells.

  12. Executive dysfunction affects word list recall performance: Evidence from amyotrophic lateral sclerosis and other neurodegenerative diseases.

    PubMed

    Consonni, Monica; Rossi, Stefania; Cerami, Chiara; Marcone, Alessandra; Iannaccone, Sandro; Francesco Cappa, Stefano; Perani, Daniela

    2017-03-01

    The Rey Auditory Verbal Learning Test (RAVLT) is widely used in clinical practice to evaluate verbal episodic memory. While there is evidence that RAVLT performance can be influenced by executive dysfunction, the way executive disorders affect the serial position curve (SPC) has not been yet explored. To this aim, we analysed immediate and delayed recall performances of 13 non-demented amyotrophic lateral sclerosis (ALS) patients with a specific mild executive dysfunction (ALSci) and compared their performances to those of 48 healthy controls (HC) and 13 cognitively normal patients with ALS. Moreover, to control for the impact of a severe dysexecutive syndrome and a genuine episodic memory deficit on the SPC, we enrolled 15 patients with a diagnosis of behavioural variant of frontotemporal dementia (bvFTD) and 18 patients with probable Alzheimer's disease (AD). Results documented that, compared to cognitively normal subjects, ALSci patients had a selective mid-list impairment for immediate recall scores. The bvFTD group obtained low performances with a selectively increased forgetting rate for terminal items, whereas the AD group showed a disproportionately large memory loss on the primary and middle part of the SPC for immediate recall scores and were severely impaired in the delayed recall trial. These results suggested that subtle executive dysfunctions might influence the recall of mid-list items, possibly reflecting deficiency in control strategies at retrieval of word lists, whereas severer dysexecutive syndrome might also affect the recall of terminal items possibly due to attention deficit or retroactive interference.

  13. Neural Efficiency in Expert Cognitive-Motor Performers During Affective Challenge.

    PubMed

    Costanzo, Michelle E; VanMeter, John W; Janelle, Christopher M; Braun, Allen; Miller, Matthew W; Oldham, Jessica; Russell, Bartlett A H; Hatfield, Bradley D

    2016-01-01

    Skilled individuals demonstrate a spatially localized or relatively lower response in brain activity characterized as neural efficiency when performing within their domain of expertise. Elite athletes are experts in their chosen sport and thus must be not only adept in the motor domain but must be resilient to performing under the stress of high-level competition. Such stability of performance suggests this population processes emotion and mental stress in an adaptive and efficient manner. This study sought to determine if athletes with a history of successful performance under circumstances of mental stress demonstrate neural efficiency during affective challenges compared to age-matched controls. Using functional magnetic resonance imaging, the blood-oxygen level-dependent response was recorded during emotional challenge induced by sport-specific and general unpleasant images. The athletes demonstrated neural efficiency in brain regions critical to emotion regulation (prefrontal cortex) and affect (insula) independently of their domain of expertise, suggesting adaptive processing of negative events and less emotional reactivity to unpleasant stimuli.

  14. Improved Dynamic Modeling of the Cascade Distillation Subsystem and Analysis of Factors Affecting Its Performance

    NASA Technical Reports Server (NTRS)

    Perry, Bruce A.; Anderson, Molly S.

    2015-01-01

    The Cascade Distillation Subsystem (CDS) is a rotary multistage distiller being developed to serve as the primary processor for wastewater recovery during long-duration space missions. The CDS could be integrated with a system similar to the International Space Station Water Processor Assembly to form a complete water recovery system for future missions. A preliminary chemical process simulation was previously developed using Aspen Custom Modeler® (ACM), but it could not simulate thermal startup and lacked detailed analysis of several key internal processes, including heat transfer between stages. This paper describes modifications to the ACM simulation of the CDS that improve its capabilities and the accuracy of its predictions. Notably, the modified version can be used to model thermal startup and predicts the total energy consumption of the CDS. The simulation has been validated for both NaC1 solution and pretreated urine feeds and no longer requires retuning when operating parameters change. The simulation was also used to predict how internal processes and operating conditions of the CDS affect its performance. In particular, it is shown that the coefficient of performance of the thermoelectric heat pump used to provide heating and cooling for the CDS is the largest factor in determining CDS efficiency. Intrastage heat transfer affects CDS performance indirectly through effects on the coefficient of performance.

  15. MoO3 Nanodots Decorated CdS Nanoribbons for High-Performance, Homojunction Photovoltaic Devices on Flexible Substrates.

    PubMed

    Shao, Zhibin; Jie, Jiansheng; Sun, Zheng; Xia, Feifei; Wang, Yuming; Zhang, Xiaohong; Ding, Ke; Lee, Shuit-Tong

    2015-05-13

    The p-n homojunctions are essential components for high-efficiency optoelectronic devices. However, the lack of p-type doping in CdS nanostructures hampers the fabrication of efficient photovoltaic (PV) devices from homojunctions. Here we report a facile solution-processed method to achieve efficient p-type doping in CdS nanoribbons (NRs) via a surface charge transfer mechanism by using spin-coated MoO3 nanodots (NDs). The NDs-decorated CdS NRs exhibited a hole concentration as high as 8.5 × 10(19) cm(-3), with the p-type conductivity tunable in a wide range of 7 orders of magnitude. The surface charge transfer mechanism was characterized in detail by X-ray photoelectron spectroscopy, Kelvin probe force microscopy, and first-principle calculations. CdS NR-homojunction PV devices fabricated on a flexible substrate exhibited a power conversion efficiency of 5.48%, which was significantly better than most of the CdS nanostructure-based heterojunction devices, presumably due to minimal junction defects. Devices made by connecting cells in series or in parallel exhibited enhanced power output, demonstrating the promising potential of the homojunction PV devices for device integration. Given the high efficiency of the surface charge transfer doping and the solution-processing capability of the method, our work opens up unique opportunities for high-performance, low-cost optoelectronic devices based on CdS homojunctions.

  16. Premarket assessment of devices for treatment of critical limb ischemia: the role of Objective Performance Criteria and Goals.

    PubMed

    Geraghty, Patrick J; Matsumura, Jon S; Conte, Michael S

    2009-12-01

    Medical devices are cleared for marketing approval through the Food and Drug Administration (FDA). Unique statutory requirements, such as the "least burdensome mandate," have allowed the FDA to employ non-concurrent controls in its evaluation of prospective therapies. The use of Objective Performance Criteria and Goals (OPC and OPG) for the premarket evaluation of cardiovascular devices has become established as an alternative to randomized, controlled trials (RCTs). These single-armed comparisons may facilitate rapid entry of novel devices to the market. Unlike RCTs, they do not establish superiority or non-inferiority of the examined therapy, and study populations must be carefully inspected to ensure validity of comparisons to historical controls.

  17. 49 CFR 232.405 - Design and performance standards for two-way end-of-train devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... designed and perform with the features applicable to one-way end-of-train devices described in § 232.403... and perform with the following features: (a) An emergency brake application command from the front... the rear unit or the locomotive shall be equipped with a manually operated switch on the...

  18. Science and technology of piezoelectric/diamond heterostructures for monolithically integrated high performance MEMS/NEMS/CMOS devices.

    SciTech Connect

    Auciello, O.; Sumant, A. V.; Hiller, J.; Kabius, B.; Ma, Z.; Srinivasan, S.

    2008-12-01

    This paper describes the fundamental and applied science performed to integrate piezoelectric PbZr{sub x}Ti{sub 1-x}O{sub 3} and AlN films with a novel mechanically robust ultrananocrystalline diamond layer to enable a new generation of low voltage/high-performance piezoactuated hybrid piezoelectric/diamond MEMS/NEMS devices.

  19. Analysis of Performance Resulting from the Design of Selected Hand-Held Input Control Devices and Visual Displays

    DTIC Science & Technology

    2002-02-01

    Model Builder (GFLMBJ (Software Manual). Guelph, Ontario: University of Guelph. Thomas, B., Tyerman, S., and Grimmer , K. (1998). Evaluation of Text ... text selection task. Epps (1986) compared six commonly used cursor devices to determine which were best on target acquisition, text editing and...characteristics, analysis of the user performance, and the subjective data will be used to develop pointing device guidelines that best support the

  20. Energy transfer and device performance in phosphorescent dye doped polymer light emitting diodes

    NASA Astrophysics Data System (ADS)

    Noh, Yong-Young; Lee, Chang-Lyoul; Kim, Jang-Joo; Yase, Kiyoshi

    2003-02-01

    Singlet and triplet-triplet energy transfer in phosphorescent dye doped polymer light emitting devices were investigated. Poly(N-vinylcarbazol) and poly[9,9'-di-n-hexyl-2,7-fluorene-alt- 1,4-(2,5-di-n-hexyloxy)phenylene] (PFHP) were selected as the host polymer for the phosphorescent dopants fac-tris(2-phenylpyridine) iridium(III) [Ir(ppy)3] and 2,3,7,8,12,13, 17,18-octaethyl-21H,23H-porphyrin platinum(II) (PtOEP) because of their high triplet energy levels and long phosphorescence lifetimes. In case of PVK film, efficient triplet energy transfers to both PtOEP and Ir(ppy)3 were observed. In contrast, the triplet energy transfer did not occur or was very weak from PFHP to both PtOEP and Ir(ppy)3 although usual requirements for triplet energy transfer were satisfied. Furthermore, the singlet-singlet energy transfer did not take place from PFHP to Ir(ppy)3 in doped films even though the Förster radius is more than 30 Å. However, the blended film of Ir(ppy)3 with PFHP and PMMA showed the green emission from Ir(ppy)3 via singlet energy transfer. In addition, the solution of PFHP and Ir(ppy)3 (8 wt. %) in p-xylene also showed green emission. The blocking of the energy transfers in the phosphorescent dye doped PFHP films is found to be originated from the formation of aggregates which is evident from the microscopic images taken by transmission electron microscope, atomic force microscope, and fluorescence microscope. The formation of aggregates prevents dopant molecules from being in close proximity with host molecules thereby inhibiting energy transfer processes. The phase separation deteriorates the device performance also. Therefore, the chemical compatibility of a dopant with a host polymer as well as conventional requirements for energy transfers must be significantly considered to fabricate efficient phosphorescent dye doped polymer light emitting devices.

  1. TiNi-based films for elastocaloric microcooling— Fatigue life and device performance

    NASA Astrophysics Data System (ADS)

    Ossmer, H.; Chluba, C.; Kauffmann-Weiss, S.; Quandt, E.; Kohl, M.

    2016-06-01

    The global trend of miniaturization and concomitant increase of functionality in microelectronics, microoptics, and various other fields in microtechnology leads to an emerging demand for temperature control at small scales. In this realm, elastocaloric cooling is an interesting alternative to thermoelectrics due to the large latent heat and good down-scaling behavior. Here, we investigate the elastocaloric effect due to a stress-induced phase transformation in binary TiNi and quaternary TiNiCuCo films of 20 μm thickness produced by DC magnetron sputtering. The mesoscale mechanical and thermal performance, as well as the fatigue behavior are studied by uniaxial tensile tests combined with infrared thermography and digital image correlation measurements. Binary films exhibit strong features of fatigue, involving a transition from Lüders-like to homogeneous transformation behavior within three superelastic cycles. Quaternary films, in contrast, show stable Lüders-like transformation without any signs of degradation. The elastocaloric temperature change under adiabatic conditions is -15 K and -12 K for TiNi and TiNiCuCo films, respectively. First-of-its-kind heat pump demonstrators are developed that make use of out-of-plane deflection of film bridges. Owing to their large surface-to-volume ratio, the demonstrators reveal rapid heat transfer. The TiNiCuCo-based devices, for instance, generate a temperature difference of 3.5 K within 13 s. The coefficients of performance of the demonstrators are about 3.

  2. Effects of different extraction buffers on peanut protein detectability and lateral flow device (LFD) performance.

    PubMed

    Rudolf, J; Ansari, P; Kern, C; Ludwig, T; Baumgartner, S

    2012-01-01

    The accidental uptake of peanuts can cause severe health reactions in allergic individuals. Reliable determination of traces of peanuts in food products is required to support correct labelling and therefore minimise consumers' risk. The immunoanalytical detectability of potentially allergenic peanut proteins is dependent on previous heat treatment, the extraction capacity of the applied buffer and the specificity of the antibody. In this study a lateral flow device (LFD) for the detection of peanut protein was developed and the capacity of 30 different buffers to extract proteins from mildly and strongly roasted peanut samples as well as their influence on the test strip performance were investigated. Most of the tested buffers showed good extraction capacity for putative Ara h 1 from mildly roasted peanuts. Protein extraction from dark-roasted samples required denaturing additives, which were proven to be incompatible with LFD performance. High-pH buffers increased the protein yield but inhibited signal generation on the test strip. Overall, the best results were achieved using neutral phosphate buffers but equal detectability of differently altered proteins due to food processing cannot be assured yet for immunoanalytical methods.

  3. Initial Clinical Experience Performing Patient Treatment Verification With an Electronic Portal Imaging Device Transit Dosimeter

    SciTech Connect

    Berry, Sean L.; Polvorosa, Cynthia; Cheng, Simon; Deutsch, Israel; Chao, K. S. Clifford; Wuu, Cheng-Shie

    2014-01-01

    Purpose: To prospectively evaluate a 2-dimensional transit dosimetry algorithm's performance on a patient population and to analyze the issues that would arise in a widespread clinical adoption of transit electronic portal imaging device (EPID) dosimetry. Methods and Materials: Eleven patients were enrolled on the protocol; 9 completed and were analyzed. Pretreatment intensity modulated radiation therapy (IMRT) patient-specific quality assurance was performed using a stringent local 3%, 3-mm γ criterion to verify that the planned fluence had been appropriately transferred to and delivered by the linear accelerator. Transit dosimetric EPID images were then acquired during treatment and compared offline with predicted transit images using a global 5%, 3-mm γ criterion. Results: There were 288 transit images analyzed. The overall γ pass rate was 89.1% ± 9.8% (average ± 1 SD). For the subset of images for which the linear accelerator couch did not interfere with the measurement, the γ pass rate was 95.7% ± 2.4%. A case study is presented in which the transit dosimetry algorithm was able to identify that a lung patient's bilateral pleural effusion had resolved in the time between the planning CT scan and the treatment. Conclusions: The EPID transit dosimetry algorithm under consideration, previously described and verified in a phantom study, is feasible for use in treatment delivery verification for real patients. Two-dimensional EPID transit dosimetry can play an important role in indicating when a treatment delivery is inconsistent with the original plan.

  4. Performance of a parallel algebraic multilevel preconditioner for stabilized finite element semiconductor device modeling

    NASA Astrophysics Data System (ADS)

    Lin, Paul T.; Shadid, John N.; Sala, Marzio; Tuminaro, Raymond S.; Hennigan, Gary L.; Hoekstra, Robert J.

    2009-09-01

    In this study results are presented for the large-scale parallel performance of an algebraic multilevel preconditioner for solution of the drift-diffusion model for semiconductor devices. The preconditioner is the key numerical procedure determining the robustness, efficiency and scalability of the fully-coupled Newton-Krylov based, nonlinear solution method that is employed for this system of equations. The coupled system is comprised of a source term dominated Poisson equation for the electric potential, and two convection-diffusion-reaction type equations for the electron and hole concentration. The governing PDEs are discretized in space by a stabilized finite element method. Solution of the discrete system is obtained through a fully-implicit time integrator, a fully-coupled Newton-based nonlinear solver, and a restarted GMRES Krylov linear system solver. The algebraic multilevel preconditioner is based on an aggressive coarsening graph partitioning of the nonzero block structure of the Jacobian matrix. Representative performance results are presented for various choices of multigrid V-cycles and W-cycles and parameter variations for smoothers based on incomplete factorizations. Parallel scalability results are presented for solution of up to 108 unknowns on 4096 processors of a Cray XT3/4 and an IBM POWER eServer system.

  5. Self-Assembled, Redox-Active Graphene Electrodes for High-Performance Energy Storage Devices.

    PubMed

    Liu, Tianyuan; Kavian, Reza; Kim, Inkyu; Lee, Seung Woo

    2014-12-18

    Graphene-based materials have been utilized as a promising approach in designing high-performance electrodes for energy storage devices. In line with this approach, functionalized graphene electrodes have been self-assembled from the dispersion of graphene oxide (GO) in water at a low temperature of 80 °C using tetrahydroxyl-1,4-benzoquinone (THQ) as both the reducing and redox-active functionalization agent. We correlated the electrochemical performance of the electrode with surface oxygen chemistry, confirming the role of THQ for the reduction and redox-active functionalization process. The assembled graphene electrodes have a 3D hierarchical porous structure, which can facilitate electronic and ionic transport to support fast charge storage reactions. Utilizing the surface redox reactions introduced by THQ, the functionalized graphene electrodes exhibit high gravimetric capacities of ∼165 mA h/g in Li cells and ∼120 mA h/g in Na cells with high redox potentials over ∼3 V versus Li or Na, proposing promising positive electrodes for both Li and Na ion batteries.

  6. The Effect of Surface Morphology on Corrosion Performance of SS 316 LVM Biomedical Devices

    NASA Astrophysics Data System (ADS)

    Toloei, Alisina; Guo, Mengnan; Rotermund, Harm H.

    2015-10-01

    In this study, in order to investigate the relationship between surface roughness and the corrosion resistance of the SS 316 LVM wires, samples have been prepared with different surface roughness by using different grits of SiC papers. In order to simulate the environment of implanted biomedical devices, a three-electrode electrochemical cell with 0.9% (by mass) NaCl solution has been used to test the corrosion resistance of the samples by potentiodynamic method and anodic polarization tests. SEM, EDS, and XPS have been performed to analyze the surfaces appearance and chemical elements on the surface before and after the corrosion. AFM was also used to get 3D images of the surface and to show the change in roughness of the samples after corrosion testing. Background-subtracted contrast-enhanced microscopy has been performed in situ to detect the pitting process happening on the surface of stainless steel samples. It was concluded that a relatively smoother surface can result in higher corrosion resistance and larger potential of stable pitting, whereas a rougher surface can easily go into stable pitting with lower pitting potentials. Rougher surfaces also showed a shorter time for the formation of stable pits. Microscopy observations illustrated more corrosion on rougher surfaces, and EDS showed more chloride ion remained on these surfaces.

  7. Device and morphological engineering of organic solar cells for enhanced charge transport and photovoltaic performance

    NASA Astrophysics Data System (ADS)

    Adhikari, Nirmal; Khatiwada, Devendra; Dubey, Ashish; Qiao, Qiquan

    2015-01-01

    Conjugated polymers are potential materials for photovoltaic applications due to their high absorption coefficient, mechanical flexibility, and solution-based processing for low-cost solar cells. A bulk heterojunction (BHJ) structure made of donor-acceptor composite can lead to high charge transfer and power conversion efficiency. Active layer morphology is a key factor for device performance. Film formation processes (e.g., spray-coating, spin-coating, and dip-coating), post-treatment (e.g., annealing and UV ozone treatment), and use of additives are typically used to engineer the morphology, which optimizes physical properties, such as molecular configuration, miscibility, lateral and vertical phase separation. We will review electronic donor-acceptor interactions in conjugated polymer composites, the effect of processing parameters and morphology on solar cell performance, and charge carrier transport in polymer solar cells. This review provides the basis for selection of different processing conditions for optimized nanomorphology of active layers and reduced bimolecular recombination to enhance open-circuit voltage, short-circuit current density, and fill factor of BHJ solar cells.

  8. Portable electro-optic device for performing serviceability check on IR guided missiles

    NASA Astrophysics Data System (ADS)

    Maini, A. K.; Agrawal, V.

    2009-09-01

    Electro-optically guided weapons are the most potent and widely used munitions on land-based, aerial and ship-borne platforms because of their proven precision strike capability. Two such guided weapon categories include the IR guided surface-to-air and air-to-air missiles and laser guided bombs and missiles. The efficacy of the mission is critically dependent on the successful deployment of the weapon. This not only necessitates that periodic functionality check be carried out on these weapons, it should also be possible to perform functionality check also known as serviceability check even after they are strapped on to the launch platform. Serviceability check in the strap-on condition ensures a much higher hit probability. This paper presents the design and development of a portable electro-optic device that generates IR signatures in 3-5-µm band having the desired amplitude and spectral shape to match the IR signatures of target aircraft. A prototype was built using the proposed concept. The prototype was characterized in terms of its output amplitude and wavelength spectrum. The prototype was used to perform serviceability check on IR seekers of foreign origin. Test results are presented in the paper.

  9. How explicit and implicit test instructions in an implicit learning task affect performance.

    PubMed

    Witt, Arnaud; Puspitawati, Ira; Vinter, Annie

    2013-01-01

    Typically developing children aged 5 to 8 years were exposed to artificial grammar learning. Following an implicit exposure phase, half of the participants received neutral instructions at test while the other half received instructions making a direct, explicit reference to the training phase. We first aimed to assess whether implicit learning operated in the two test conditions. We then evaluated the differential impact of age on learning performances as a function of test instructions. The results showed that performance did not vary as a function of age in the implicit instructions condition, while age effects emerged when explicit instructions were employed at test. However, performance was affected differently by age and the instructions given at test, depending on whether the implicit learning of short or long units was assessed. These results suggest that the claim that the implicit learning process is independent of age needs to be revised.

  10. Study of parameters affecting the performance of solar desiccant cooling systems

    SciTech Connect

    Pesaran, A A; Hoo, E A

    1993-01-01

    The performance of a solar desiccant cooling system depends on the performance of its components, particularly the desiccant dehumidifier and solar collectors. The desiccant dehumidifier performance is affected by the properties of the desiccant, particularly the shape of the isotherm and the regeneration temperature. The performance of a solar collector, as one would expect, depends on its operating temperature, which is very close to the desiccant regeneration temperature. The purpose of this study was to identify the desiccant isotherm shape (characterized by separation factor) that would result in the optimum performance - based on thermal coefficient of performance and cooling capacity - of a desiccant cooling cycle operating in ventilation mode. Different regeneration temperatures ranging from 65{degree}C to 160{degree}C were investigated to identify the corresponding optimum isotherm shape at each. Thermal COP dictates the required area of the solar collectors, and the cooling capacity is an indication of the size and cost of the cooling equipment. Staged and no-staged regeneration methods were studied.

  11. Study of parameters affecting the performance of solar desiccant cooling systems

    SciTech Connect

    Pesaran, A.A.; Hoo, E.A.

    1993-01-01

    The performance of a solar desiccant cooling system depends on the performance of its components, particularly the desiccant dehumidifier and solar collectors. The desiccant dehumidifier performance is affected by the properties of the desiccant, particularly the shape of the isotherm and the regeneration temperature. The performance of a solar collector, as one would expect, depends on its operating temperature, which is very close to the desiccant regeneration temperature. The purpose of this study was to identify the desiccant isotherm shape (characterized by separation factor) that would result in the optimum performance - based on thermal coefficient of performance and cooling capacity - of a desiccant cooling cycle operating in ventilation mode. Different regeneration temperatures ranging from 65[degree]C to 160[degree]C were investigated to identify the corresponding optimum isotherm shape at each. Thermal COP dictates the required area of the solar collectors, and the cooling capacity is an indication of the size and cost of the cooling equipment. Staged and no-staged regeneration methods were studied.

  12. Effect of device design on the in vitro performance and comparability for capsule-based dry powder inhalers.

    PubMed

    Shur, Jagdeep; Lee, Sau; Adams, Wallace; Lionberger, Robert; Tibbatts, James; Price, Robert

    2012-12-01

    This study investigated the effect of modifying the design of the Cyclohaler on its aerosolization performance and comparability to the HandiHaler at multiple flow rates. The Cyclohaler and HandiHaler were designated as model test and reference unit-dose, capsule-based dry powder inhalers (DPIs), respectively. The flow field, pressure drop, and carrier particle trajectories within the Cyclohaler and HandiHaler were modeled via computational fluid dynamics (CFD). With the goal of achieving in vitro comparability to the HandiHaler, the CFD results were used to identify key device attributes and to design two modifications of the Cyclohaler (Mod 1 and Mod 2), which matched the specific resistance of the HandiHaler but exhibited different cyclonic flow conditions in the device. Aerosolization performance of the four DPI devices was evaluated by using the reference product's capsule and formulation (Spiriva capsule) and a multistage cascade impactor. The in vitro data showed that Mod 2 provided a closer match to the HandiHaler than the Cyclohaler and Mod 1 at 20, 39, and 55 l/min. The in vitro and CFD results together suggest that matching the resistance of test and reference DPI devices is not sufficient to attain comparable aerosolization performance, and the improved in vitro comparability of Mod 2 to the HandiHaler may be related to the greater degree of similarities of the flow rate of air through the pierced capsule (Q(c)) and the maximum impact velocity of representative carrier particles (V(n)) in the Cyclohaler-based device. This investigation illustrates the importance of enhanced product understanding, in this case through the CFD modeling and in vitro characterization of aerosolization performance, to enable identification and modification of key design features of a test DPI device for achieving comparable aerosolization performance to the reference DPI device.

  13. Distractions, distractions: does instant messaging affect college students' performance on a concurrent reading comprehension task?

    PubMed

    Fox, Annie Beth; Rosen, Jonathan; Crawford, Mary

    2009-02-01

    Instant messaging (IM) has become one of the most popular forms of computer-mediated communication (CMC) and is especially prevalent on college campuses. Previous research suggests that IM users often multitask while conversing online. To date, no one has yet examined the cognitive effect of concurrent IM use. Participants in the present study (N = 69) completed a reading comprehension task uninterrupted or while concurrently holding an IM conversation. Participants who IMed while performing the reading task took significantly longer to complete the task, indicating that concurrent IM use negatively affects efficiency. Concurrent IM use did not affect reading comprehension scores. Additional analyses revealed that the more time participants reported spending on IM, the lower their reading comprehension scores. Finally, we found that the more time participants reported spending on IM, the lower their self-reported GPA. Implications and future directions are discussed.

  14. Swimming performance of hatchling green turtles is affected by incubation temperature

    NASA Astrophysics Data System (ADS)

    Burgess, Elizabeth A.; Booth, David T.; Lanyon, Janet M.

    2006-08-01

    In an experiment repeated for two separate years, incubation temperature was found to affect the body size and swimming performance of hatchling green turtles ( Chelonia mydas). In the first year, hatchlings from eggs incubated at 26°C were larger in size than hatchlings from 28 and 30°C, whilst in the second year hatchlings from 25.5°C were similar in size to hatchings from 30°C. Clutch of origin influenced the size of hatchlings at all incubation temperatures even when differences in egg size were taken into account. In laboratory measurements of swimming performance, in seawater at 28°C, hatchlings from eggs incubated at 25.5 and 26°C had a lower stroke rate frequency and lower force output than hatchlings from 28 and 30°C. These differences appeared to be caused by the muscles of hatchlings from cooler temperatures fatiguing at a faster rate. Clutch of origin did not influence swimming performance. This finding that hatchling males incubated at lower temperature had reduced swimming ability may affect their survival whilst running the gauntlet of predators in shallow near-shore waters, prior to reaching the relative safety of the open sea.

  15. Mass Rearing History and Irradiation Affect Mating Performance of the Male Fruit Fly, Anastrepha obliqua

    PubMed Central

    Rull, Juan; Encarnación, Nery; Birke, Andrea

    2012-01-01

    As an initial step to improve the efficiency of the sterile insect technique applied to eradicate, suppress, and control wild Anastrepha obliqua (Macquart) (Diptera: Tephritidae) in mango producing areas of Mexico, the effect of radiation dose and mass rearing history on male mating performance was examined. Field cage tests in which both male and female laboratory flies were irradiated at different doses (0, 40, and 80 Gy) were released with cohorts of wild flies of both sexes, revealing that both mass rearing history and irradiation affected male mating performance. Laboratory males were accepted for copulation by wild females less frequently than wild males. Copulations involving laboratory males were shorter than those involving wild males. Irradiated males mated less frequently with wild females than wild males, and irradiated females appeared to be less able to reject courting males of both origins. High levels of fertility for untreated laboratory females crossed with males irradiated at different doses may reflect problems in mass rearing affecting homogeneity of pupal age before irradiation, and possibly masked a dose effect. Proposed remedial measures to improve male mating performance are discussed. PMID:22957485

  16. Timing of examinations affects school performance differently in early and late chronotypes.

    PubMed

    van der Vinne, Vincent; Zerbini, Giulia; Siersema, Anne; Pieper, Amy; Merrow, Martha; Hut, Roelof A; Roenneberg, Till; Kantermann, Thomas

    2015-02-01

    Circadian clocks of adolescents typically run late-including sleep times-yet adolescents generally are expected at school early in the morning. Due to this mismatch between internal (circadian) and external (social) times, adolescents suffer from chronic sleep deficiency, which, in turn, affects academic performance negatively. This constellation affects students' future career prospects. Our study correlates chronotype and examination performance. In total, 4734 grades were collected from 741 Dutch high school students (ages 11-18 years) who had completed the Munich ChronoType Questionnaire to estimate their internal time. Overall, the lowest grades were obtained by students who were very late chronotypes (MSFsc > 5.31 h) or slept very short on schooldays (SDw < 7.03 h). The effect of chronotype on examination performance depended on the time of day that examinations were taken. Opposed to late types, early chronotypes obtained significantly higher grades during the early (0815-0945 h) and late (1000-1215 h) morning. This group difference in grades disappeared in the early afternoon (1245-1500 h). Late types also obtained lower grades than early types when tested at the same internal time (hours after MSFsc), which may reflect general attention and learning disadvantages of late chronotypes during the early morning. Our results support delaying high school starting times as well as scheduling examinations in the early afternoon to avoid discrimination of late chronotypes and to give all high school students equal academic opportunities.

  17. 40 CFR Table 3 to Subpart Nnnnn of... - Performance Test Requirements for HCl Production Affected Sources

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the control device prior to any releases to the atmosphere (or, if a series of control devices are... any releases to the atmosphere); or ii. If complying with an outlet concentration emission limitation... to the atmosphere or, if no control device is used, prior to any releases to the atmosphere....

  18. 40 CFR Table 3 to Subpart Nnnnn of... - Performance Test Requirements for HCl Production Affected Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the control device prior to any releases to the atmosphere (or, if a series of control devices are... any releases to the atmosphere); or ii. If complying with an outlet concentration emission limitation... to the atmosphere or, if no control device is used, prior to any releases to the atmosphere....

  19. 40 CFR Table 3 to Subpart Nnnnn of... - Performance Test Requirements for HCl Production Affected Sources

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the control device prior to any releases to the atmosphere (or, if a series of control devices are... any releases to the atmosphere); or ii. If complying with an outlet concentration emission limitation... to the atmosphere or, if no control device is used, prior to any releases to the atmosphere....

  20. Fabrication and performance of pressure-sensing device consisting of electret film and organic semiconductor

    NASA Astrophysics Data System (ADS)

    Kodzasa, Takehito; Nobeshima, Daiki; Kuribara, Kazunori; Uemura, Sei; Yoshida, Manabu

    2017-04-01

    We propose a new concept of a pressure-sensitive device that consists of an organic electret film and an organic semiconductor. This device exhibits high sensitivity and selectivity against various types of pressure. The sensing mechanism of this device originates from a modulation of the electric conductivity of the organic semiconductor film induced by the interaction between the semiconductor film and the charged electret film placed face to face. It is expected that a complicated sensor array will be fabricated by using a roll-to-roll manufacturing system, because this device can be prepared by an all-printing and simple lamination process without high-level positional adjustment for printing processes. This also shows that this device with a simple structure is suitable for application to a highly flexible device array sheet for an Internet of Things (IoT) or wearable sensing system.

  1. Prolonged self-paced exercise in the heat – environmental factors affecting performance

    PubMed Central

    Junge, Nicklas; Jørgensen, Rasmus; Flouris, Andreas D.; Nybo, Lars

    2016-01-01

    ABSTRACT In this review we examine how self-paced performance is affected by environmental heat stress factors during cycling time trial performance as well as considering the effects of exercise mode and heat acclimatization. Mean power output during prolonged cycling time trials in the heat (≥30°C) was on average reduced by 15% in the 14 studies that fulfilled the inclusion criteria. Ambient temperature per se was a poor predictor of the integrated environmental heat stress and 2 of the prevailing heat stress indices (WBGT and UTCI) failed to predict the environmental influence on performance. The weighing of wind speed appears to be too low for predicting the effect for cycling in trained acclimatized subjects, where performance may be maintained in outdoor time trials at ambient temperatures as high as 36°C (36°C UTCI; 28°C WBGT). Power output during indoor trials may also be maintained with temperatures up to at least 27°C when humidity is modest and wind speed matches the movement speed generated during outdoor cycling, whereas marked reductions are observed when air movement is minimal. For running, representing an exercise mode with lower movement speed and higher heat production for a given metabolic rate, it appears that endurance is affected even at much lower ambient temperatures. On this basis we conclude that environmental heat stress impacts self-paced endurance performance. However, the effect is markedly modified by acclimatization status and exercise mode, as the wind generated by the exercise (movement speed) or the environment (natural or fan air movement) exerts a strong influence. PMID:28090557

  2. Prolonged self-paced exercise in the heat - environmental factors affecting performance.

    PubMed

    Junge, Nicklas; Jørgensen, Rasmus; Flouris, Andreas D; Nybo, Lars

    2016-01-01

    In this review we examine how self-paced performance is affected by environmental heat stress factors during cycling time trial performance as well as considering the effects of exercise mode and heat acclimatization. Mean power output during prolonged cycling time trials in the heat (≥30°C) was on average reduced by 15% in the 14 studies that fulfilled the inclusion criteria. Ambient temperature per se was a poor predictor of the integrated environmental heat stress and 2 of the prevailing heat stress indices (WBGT and UTCI) failed to predict the environmental influence on performance. The weighing of wind speed appears to be too low for predicting the effect for cycling in trained acclimatized subjects, where performance may be maintained in outdoor time trials at ambient temperatures as high as 36°C (36°C UTCI; 28°C WBGT). Power output during indoor trials may also be maintained with temperatures up to at least 27°C when humidity is modest and wind speed matches the movement speed generated during outdoor cycling, whereas marked reductions are observed when air movement is minimal. For running, representing an exercise mode with lower movement speed and higher heat production for a given metabolic rate, it appears that endurance is affected even at much lower ambient temperatures. On this basis we conclude that environmental heat stress impacts self-paced endurance performance. However, the effect is markedly modified by acclimatization status and exercise mode, as the wind generated by the exercise (movement speed) or the environment (natural or fan air movement) exerts a strong influence.

  3. Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis

    PubMed Central

    He, Hanzi; de Souza Vidigal, Deborah; Snoek, L. Basten; Schnabel, Sabine; Nijveen, Harm; Hilhorst, Henk; Bentsink, Leónie

    2014-01-01

    Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits. PMID:25240065

  4. Interaction between parental environment and genotype affects plant and seed performance in Arabidopsis.

    PubMed

    He, Hanzi; de Souza Vidigal, Deborah; Snoek, L Basten; Schnabel, Sabine; Nijveen, Harm; Hilhorst, Henk; Bentsink, Leónie

    2014-12-01

    Seed performance after dispersal is highly dependent on parental environmental cues, especially during seed formation and maturation. Here we examine which environmental factors are the most dominant in this respect and whether their effects are dependent on the genotypes under investigation. We studied the influence of light intensity, photoperiod, temperature, nitrate, and phosphate during seed development on five plant attributes and thirteen seed attributes, using 12 Arabidopsis genotypes that have been reported to be affected in seed traits. As expected, the various environments during seed development resulted in changed plant and/or seed performances. Comparative analysis clearly indicated that, overall, temperature plays the most dominant role in both plant and seed performance, whereas light has a prominent impact on plant traits. In comparison to temperature and light, nitrate mildly affected some of the plant and seed traits while phosphate had even less influence on those traits. Moreover, clear genotype-by-environment interactions were identified. This was shown by the fact that individual genotypes responded differentially to the environmental conditions. Low temperature significantly increased seed dormancy and decreased seed longevity of NILDOG1 and cyp707a1-1, whereas low light intensity increased seed dormancy and decreased seed longevity of NILDOG3 and NILDOG6. This also indicates that different genetic and molecular pathways are involved in the plant and seed responses. By identifying environmental conditions that affect the dormancy vs longevity correlation in the same way as previously identified naturally occurring loci, we have identified selective forces that probably shaped evolution for these important seed traits.

  5. The empirical validation of a model for simulating the thermal and electrical performance of fuel cell micro-cogeneration devices

    NASA Astrophysics Data System (ADS)

    Beausoleil-Morrison, Ian

    Fuel cell micro-cogeneration is a nascent technology that can potentially reduce the energy consumption and environmental impact associated with serving building electrical and thermal demands. Accurately assessing these potential benefits and optimizing the integration of micro-cogeneration within buildings requires simulation methods that enable the integrated modelling of fuel cell micro-cogeneration devices with the thermal and electrical performance of the host building and other plant components. Such a model has recently been developed and implemented into a number of building simulation programs as part of an International Energy Agency research project. To date, the model has been calibrated (tuned) for one particular prototype 2.8 kWAC solid-oxide fuel cell (SOFC) micro-cogeneration device. The current paper examines the validity of this model by contrasting simulation predictions to measurements from the 2.8 kWAC prototype device. Good agreement was found in the predictions of DC power production, the rate of fuel consumption, and energy conversion efficiencies. Although there was greater deviation between simulation predictions and measurements in the predictions of useful thermal output, acceptable agreement was found within the uncertainty of the model and the measurements. It is concluded that the form of the mathematical model can accurately represents the performance of SOFC micro-cogeneration devices and that detailed performance assessments can now be performed with the calibrated model to examine the applicability of the 2.8 kWAC prototype device for supplying building electrical and thermal energy requirements.

  6. The effect of substrate temperature on material properties and the device performance of close-spaced sublimation deposited CdTe/CdS devices

    NASA Astrophysics Data System (ADS)

    Li, X.; Albin, D.; Asher, S.; Moutinho, H.; Keyes, B.; Matson, R.; Hasoon, F.; Sheldon, P.

    1996-01-01

    High-efficiency polycrystalline CdS/CdTe solar cells have been fabricated using CdTe absorber layers deposited by close-spaced sublimation (CSS). CSS employs high substrate temperatures (Tsub) during film growth, which can promote the formation of larger grains and higher Voc's yielding better device performance. However, as Tsub increases beyond 610 °C, voids or pinholes begin to form in the CdTe layer. When the back contact is applied, these voids serve as shunt paths that effectively lower Voc. In this fashion, benefits associated with higher substrate temperatures are seriously compromised. Concurrent with voiding is the observation that higher temperatures promote interdiffusion at the CdS/CdTe interface such that the effective thickness of the CdS layer is reduced. Variations in processing that correct for these detrimental effects have led to a total-area device efficiency of 12%.

  7. Performance level affects the dietary supplement intake of both individual and team sports athletes.

    PubMed

    Giannopoulou, Ifigenia; Noutsos, Kostantinos; Apostolidis, Nikolaos; Bayios, Ioannis; Nassis, George P

    2013-01-01

    Dietary supplement (DS) intake is high in elite level athletes, however few studies have investigated the impact that the performance level of the athletes has on supplementation intake in individual and team sports. The purpose of the study was to determine and compare the DS intake among individual and team sport athletes of various performance levels. A total of 2845 participants (athletes: 2783, controls: 62) between the ages of 11 and 44 years old participated in the study. A 3-page questionnaire was developed to assess the intake of DS. Athletes were categorized based on participation in individual (n = 775) and team sports (n = 2008). To assess the effect of performance level in supplementation intake, athletes were categorized based on training volume, participation in the national team, and winning at least one medal in provincial, national, international or Olympic games. Overall, 37% of all athletes of various performance levels reported taking at least one DS in the last month. A higher prevalence of DS intake was reported in individual (44%) compared to team sport athletes (35%) (p < 0.001). Athletes of high performance level reported greater DS intake compared to lower performance athletes. Males reported a significantly greater prevalence of DS intake compared to females. The most popular supplement reported was amino acid preparation with the main reason of supplementation being endurance improvements. In conclusion, performance level and type of sport appear to impact the DS practices of male and female athletes. These findings should be validated in other populations. Key points37% of Mediterranean athletes of various sports and levels have reported taking dietary supplements.The performance level of the athletes affects the dietary supplementation intake.Athletes in individual sports appear to have a higher DS intake compared to team sport athletes.Male athletes appear to take more dietary supplements compared to female athletes.

  8. Performance Level Affects the Dietary Supplement Intake of Both Individual and Team Sports Athletes

    PubMed Central

    Giannopoulou, Ifigenia; Noutsos, Kostantinos; Apostolidis, Nikolaos; Bayios, Ioannis; Nassis, George P.

    2013-01-01

    Dietary supplement (DS) intake is high in elite level athletes, however few studies have investigated the impact that the performance level of the athletes has on supplementation intake in individual and team sports. The purpose of the study was to determine and compare the DS intake among individual and team sport athletes of various performance levels. A total of 2845 participants (athletes: 2783, controls: 62) between the ages of 11 and 44 years old participated in the study. A 3-page questionnaire was developed to assess the intake of DS. Athletes were categorized based on participation in individual (n = 775) and team sports (n = 2008). To assess the effect of performance level in supplementation intake, athletes were categorized based on training volume, participation in the national team, and winning at least one medal in provincial, national, international or Olympic games. Overall, 37% of all athletes of various performance levels reported taking at least one DS in the last month. A higher prevalence of DS intake was reported in individual (44%) compared to team sport athletes (35%) (p < 0.001). Athletes of high performance level reported greater DS intake compared to lower performance athletes. Males reported a significantly greater prevalence of DS intake compared to females. The most popular supplement reported was amino acid preparation with the main reason of supplementation being endurance improvements. In conclusion, performance level and type of sport appear to impact the DS practices of male and female athletes. These findings should be validated in other populations. Key points 37% of Mediterranean athletes of various sports and levels have reported taking dietary supplements. The performance level of the athletes affects the dietary supplementation intake. Athletes in individual sports appear to have a higher DS intake compared to team sport athletes. Male athletes appear to take more dietary supplements compared to female athletes. PMID

  9. Cybersecurity Regulation of Wireless Devices for Performance and Assurance in the Age of "Medjacking".

    PubMed

    Armstrong, David G; Kleidermacher, David N; Klonoff, David C; Slepian, Marvin J

    2015-08-27

    We are rapidly reaching a point where, as connected devices for monitoring and treating diabetes and other diseases become more pervasive and powerful, the likelihood of malicious medical device hacking (known as "medjacking") is growing. While government could increase regulation, we have all been witness in recent times to the limitations and issues surrounding exclusive reliance on government. Herein we outline a preliminary framework for establishing security for wireless health devices based on international common criteria. Creation of an independent medical device cybersecurity body is suggested. The goal is to allow for continued growth and innovation while simultaneously fostering security, public trust, and confidence.

  10. Cybersecurity Regulation of Wireless Devices for Performance and Assurance in the Age of “Medjacking”

    PubMed Central

    Armstrong, David G.; Kleidermacher, David N.; Klonoff, David C.; Slepian, Marvin J.

    2015-01-01

    We are rapidly reaching a point where, as connected devices for monitoring and treating diabetes and other diseases become more pervasive and powerful, the likelihood of malicious medical device hacking (known as “medjacking”) is growing. While government could increase regulation, we have all been witness in recent times to the limitations and issues surrounding exclusive reliance on government. Herein we outline a preliminary framework for establishing security for wireless health devices based on international common criteria. Creation of an independent medical device cybersecurity body is suggested. The goal is to allow for continued growth and innovation while simultaneously fostering security, public trust, and confidence. PMID:26319227

  11. Rapid weight loss followed by recovery time does not affect judo-related performance.

    PubMed

    Artioli, Guilherme G; Iglesias, Rodrigo T; Franchini, Emerson; Gualano, Bruno; Kashiwagura, Daniel B; Solis, Marina Y; Benatti, Fabiana B; Fuchs, Marina; Lancha Junior, Antonio H

    2010-01-01

    In this study, we investigated the effects of rapid weight loss followed by a 4-h recovery on judo-related performance. Seven weight-cycler athletes were assigned to a weight loss group (5% body weight reduction by self-selected regime) and seven non-weight-cyclers to a control group (no weight reduction). Body composition, performance, glucose, and lactate were assessed before and after weight reduction (5-7 days apart; control group kept weight stable). The weight loss group had 4 h to re-feed and rehydrate after the weigh-in. Food intake was recorded during the weight loss period and recovery after the weigh-in. Performance was evaluated through a specific judo exercise, followed by a 5-min judo combat and by three bouts of the Wingate test. Both groups significantly improved performance after the weight loss period. No interaction effects were observed. The energy and macronutrient intake of the weight loss group were significantly lower than for the control group. The weight loss group consumed large amounts of food and carbohydrate during the 4-h recovery period. No changes were observed in lactate concentration, but a significant decrease in glucose during rest was observed in the weight loss group. In conclusion, rapid weight loss did not affect judo-related performance in experienced weight-cyclers when the athletes had 4 h to recover. These results should not be extrapolated to inexperienced weight-cyclers.

  12. School performance and school behavior of children affected by AIDS in China.

    PubMed

    Tu, Xiaoming; Lv, Yunfei; Li, Xiaoming; Fang, Xiaoyi; Zhao, Guoxiang; Lin, Xiuyun; Hong, Yan; Zhang, Liying; Stanton, Bonita

    2009-09-01

    It is generally recognized that the AIDS epidemic will have a negative effect on the orphans' school education. However, few studies have been carried out to examine the school performance and school behavior of AIDS orphans and vulnerable children (children living with HIV-infected parents). Using both self-report and teacher evaluation data of 1625 children from rural central China, we examined the impact of parental HIV/AIDS on children's school performances (academic marks, educational expectation, and student leadership) and school behaviors (e.g., aggression, shy/anxious and assertive social skills). Results indicate that AIDS orphans and vulnerable children had disadvantages in school performances in comparison to their peers from the same community who did not experience AIDS-related death and illness in their family (comparison children). AIDS orphans had the lowest academic marks based on the reports of both children and teachers. Educational expectation was significantly lower among AIDS orphans and vulnerable children than comparison children from teacher's perspective. AIDS orphans were significantly more likely to demonstrate aggressive, impulsive and anxious behaviors than non-orphans. Moreover, orphans have more learning difficulties. Vulnerable children were also at a disadvantage on most measures. The data suggest that a greater attention is needed to the school performance and behavior of children affected by AIDS. The findings also indicate that AIDS relief and assistance program for children should go beyond the school attendance and make efforts to improve their school performance and education aspiration.

  13. Performance Analysis of Si3N4 Capping Layer and SOI Technology in Sub 90 nm PMOS Device

    NASA Astrophysics Data System (ADS)

    Rahim, Noor Ashikin Binti Abdul; Abdullah, Mohd. Hanapiah B.; Rusop, Mohamad

    2009-06-01

    This technical paper investigates the electrical analysis in sub 90 nm of PMOS. The investigation was carried out by using two different methods which is PMOS with strained silicon and Silicon-on-Insulator (SOI) technology. Strained silicon engineering has become a key innovation to enhance device on current. Recently, SOI technology has been widely accepted for use in mainstream high performance logic applications due to some advantageous offered over the bulk silicon. The performance of the devices is analyzed by focusing on the electrical characteristics of Id-Vd and Id-Vg curves for three different structures. Firstly, PMOS with strained silicon of Si3N4 capping layer covering the gate area and secondly the device with and without SOI technology. The fabrication process simulation was simulated by using SILVACO TCAD ATHENA simulator and the electrical characteristic was simulated by SILVACO TCAD ATLAS simulator to obtain Id-Vd and Id-Vg curves. A fruitful and knowledgeable results were reported from this paper, it could be seen that high tensile strain introduced to the device causing the drain current to decreased from Id(bulk) = -400 uA/um of bulk to Id(Strain) = -310 uA/um which is about 25% of decrement. Since the drain current decreased, the carrier mobility and the performance also decreased proportional to drain current. However when SOI technology is applied to the PMOS device, the drain current was increased up to Id(SOI) = -431 uA/um over the bulk, the increment of about 9.25% reported. A higher Id-Vg curve and lower threshold of about pVth(SOI) = -0.2178 V also reported from this paper which tells that the device with SOI technology exhibits low power consumption device and fast switching which in turns contribute to a faster performance.

  14. Room temperature synthesis of cobalt-manganese-nickel oxalates micropolyhedrons for high-performance flexible electrochemical energy storage device

    PubMed Central

    Zhang, Yi-Zhou; Zhao, Junhong; Xia, Jing; Wang, Lulu; Lai, Wen-Yong; Pang, Huan; Huang, Wei

    2015-01-01

    Cobalt-manganese-nickel oxalates micropolyhedrons were successfully fabricated by a room temperature chemical co-precipitation method. Interestingly, the Co0.5Mn0.4Ni0.1C2O4*nH2O micropolyhedrons and graphene nanosheets have been successfully applied as the positive and negative electrode materials (a battery type Faradaic electrode and a capacitive electrode, respectively) for flexible solid-state asymmetric supercapacitors. More importantly, the as-assembled device achieved a maximum energy density of 0.46 mWh·cm−3, a decent result among devices with similar structures. The as-assembled device showed good flexibility, functioning well under both normal and bent conditions (0°–180°). The resulting device showed little performance decay even after 6000 cycles, which rendered the Co0.5Mn0.4Ni0.1C2O4*nH2O//Graphene device configuration a promising candidate for high-performance flexible solid-state asymmetric supercapacitors in the field of high-energy-density energy storage devices. PMID:25705048

  15. The Functional Effect of Teacher Positive and Neutral Affect on Task Performance of Students with Significant Disabilities

    ERIC Educational Resources Information Center

    Park, Sungho; Singer, George H. S.; Gibson, Mary

    2005-01-01

    The study uses an alternating treatment design to evaluate the functional effect of teacher's affect on students' task performance. Tradition in special education holds that teachers should engage students using positive and enthusiastic affect for task presentations and praise. To test this assumption, we compared two affective conditions. Three…

  16. Fundamentals of Modern VLSI Devices

    NASA Astrophysics Data System (ADS)

    Taur, Yuan; Ning, Tak H.

    1998-10-01

    This book examines in detail the basic properties and design, including chip integration, of CMOS and bipolar VLSI devices and discusses the various factors that affect their performance. The authors begin with a thorough review of the relevant aspects of semiconductor physics, and proceed to a description of the design of CMOS and bipolar devices. The optimization of these devices for VLSI applications is also covered. The authors highlight the intricate interdependencies and subtle tradeoffs between those device parameters, such as power consumption and packing density, that affect circuit performance and manufacturability. They also discuss in detail the scaling, and physical limits to the scaling, of CMOS and bipolar devices. The book contains many exercises, and can be used as a textbook for senior undergraduate or first-year graduate courses on microelectronics or VLSI devices. It will also be a valuable reference volume for practicing engineers involved in research and development in the electronics industry.

  17. Device performance of in situ steam generated gate dielectric nitrided by remote plasma nitridation

    NASA Astrophysics Data System (ADS)

    Al-Shareef, H. N.; Karamcheti, A.; Luo, T. Y.; Bersuker, G.; Brown, G. A.; Murto, R. W.; Jackson, M. D.; Huff, H. R.; Kraus, P.; Lopes, D.; Olsen, C.; Miner, G.

    2001-06-01

    In situ steam generated (ISSG) oxides have recently attracted interest for use as gate dielectrics because of their demonstrated reliability improvement over oxides formed by dry oxidation. [G. Minor, G. Xing, H. S. Joo, E. Sanchez, Y. Yokota, C. Chen, D. Lopes, and A. Balakrishna, Electrochem. Soc. Symp. Proc. 99-10, 3 (1999); T. Y. Luo, H. N. Al-Shareef, G. A. Brown, M. Laughery, V. Watt, A. Karamcheti, M. D. Jackson, and H. R. Huff, Proc. SPIE 4181, 220 (2000).] We show in this letter that nitridation of ISSG oxide using a remote plasma decreases the gate leakage current of ISSG oxide by an order of magnitude without significantly degrading transistor performance. In particular, it is shown that the peak normalized transconductance of n-channel devices with an ISSG oxide gate dielectric decreases by only 4% and the normalized drive current by only 3% after remote plasma nitridation (RPN). In addition, it is shown that the reliability of the ISSG oxide exhibits only a small degradation after RPN. These observations suggest that the ISSG/RPN process holds promise for gate dielectric applications.

  18. A novel approach for correlating capacitance data with performance during thin-film device stress studies

    NASA Astrophysics Data System (ADS)

    Graham, Rebekah L.; Clark, Laura A.; Albin, David S.

    2011-09-01

    A new data mining algorithm was developed to identify the strongest correlations between capacitance data (measured between -1.5 V and +0.49 V) and first- and second-level performance metrics (efficiency [η%], open-circuit voltage [VOC], short-circuit current density [JSC], and fill-factor [FF]) during the stress testing of voltage-stabilized CdS/CdTe devices. When considering only correlations between first- and second-level metrics, 96.5% of the observed variation in η% was attributed to FF. The overall decrease in VOC after 1,000 hours of open-circuit, light-soak stress at 60°C was about -1.5%. As determined by our algorithm, the most consistent correlation existing between FF and third-level metric capacitance data at all stages during stress testing was between FF and the apparent CdTe acceptor density (Na) calculated at a voltage of +0.49 V during forward voltage scans. Since the contribution of back-contact capacitance to total capacitance increases with increasing positive voltage, this result suggests that FF degradation is associated with decreases in Na near the CdTe/back contact interface. Also of interest, it appears that capacitance data at these higher voltages appears to more accurately fit the one-sided abrupt junction model.

  19. High-performance computing-based exploration of flow control with micro devices

    PubMed Central

    Fujii, Kozo

    2014-01-01

    The dielectric barrier discharge (DBD) plasma actuator that controls flow separation is one of the promising technologies to realize energy savings and noise reduction of fluid dynamic systems. However, the mechanism for controlling flow separation is not clearly defined, and this lack of knowledge prevents practical use of this technology. Therefore, large-scale computations for the study of the DBD plasma actuator have been conducted using the Japanese Petaflops supercomputer ‘K’ for three different Reynolds numbers. Numbers of new findings on the control of flow separation by the DBD plasma actuator have been obtained from the simulations, and some of them are presented in this study. Knowledge of suitable device parameters is also obtained. The DBD plasma actuator is clearly shown to be very effective for controlling flow separation at a Reynolds number of around 105, and several times larger lift-to-drag ratio can be achieved at higher angles of attack after stall. For higher Reynolds numbers, separated flow is partially controlled. Flow analysis shows key features towards better control. DBD plasma actuators are a promising technology, which could reduce fuel consumption and contribute to a green environment by achieving high aerodynamic performance. The knowledge described above can be obtained only with high-end computers such as the supercomputer ‘K’. PMID:25024414

  20. Novel Approach for Correlating Capacitance Data with Performance During Thin-Film Device Stress Studies: Preprint

    SciTech Connect

    Graham, R. L.; Albin, D. S.; Clark, L. A.

    2011-08-01

    A new data mining algorithm was developed to identify the strongest correlations between capacitance data (measured between -1.5 V and +0.49 V) and 1st and 2nd level performance metrics (efficiency, open-circuit voltage (VOC), short-circuit current density (JSC), and fill-factor (FF)) during the stress testing of voltage-stabilized CdS/CdTe devices. When considering only correlations between 1st and 2nd level metrics, 96.5% of the observed variation in efficiency was attributed to FF. The overall decrease in VOC after 1000 hours of open-circuit, light-soak stress at 60 degrees C was about 1.5%. As determined by our algorithm, the most consistent correlation existing between FF and 3rd level metric capacitance data at all stages during stress testing was between FF and the apparent CdTe acceptor density (Na) calculated at a voltage of +0.49 V during forward voltage scans. Since the contribution of back contact capacitance to total capacitance increases with increasing positive voltage, this result suggests that FF degradation is associated with decreases in Na near the CdTe/back contact interface. Also of interest, it appears that capacitance data at these higher voltages appears to more accurately fit the one-sided abrupt junction model.

  1. RF communication with implantable wireless device: effects of beating heart on performance of miniature antenna.

    PubMed

    Murphy, Olive H; Borghi, Alessandro; Bahmanyar, Mohammad Reza; McLeod, Christopher N; Navaratnarajah, Manoraj; Yacoub, Magdi; Toumazou, Christofer

    2014-06-01

    The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable antennas are presented (two different geometries) along with which are placed within the heart of living swine the dynamic reflection coefficients. These antennas are designed to operate in the short range devices frequency band (863-870 MHz) and are compatible with a deeply implanted cardiovascular pressure sensor. The measurements recorded over 27 seconds capture the effects of the beating heart on the frequency tuning of the implantable antennas. When looked at in the time domain, these effects are clearly physiological and a combination of numerical study and posthumous autopsy proves this to be the case, while retrospective simulation confirms this hypothesis. The impact of pulsating anatomy on antenna design and the need for wideband implantable antennas is highlighted.

  2. Performance of a continuous flow ventricular assist device: magnetic bearing design, construction, and testing.

    PubMed

    Allaire, P; Hilton, E; Baloh, M; Maslen, E; Bearnson, G; Noh, D; Khanwilkar, P; Olsen, D

    1998-06-01

    A new centrifugal continuous flow ventricular assist device, the CFVAD III, which is fully magnetic bearing suspended, has been developed. It has only one moving part (the impeller), has no contact (magnetic suspension), is compact, and has minimal heating. A centrifugal impeller of 2 inch outer diameter is driven by a permanent magnet brushless DC motor. This paper discusses the design, construction, testing, and performance of the magnetic bearings in the unit. The magnetic suspension consists of an inlet side magnetic bearing and an outlet side magnetic bearing, each divided into 8 pole segments to control axial and radial displacements as well as angular displacements. The magnetic actuators are composed of several different materials to minimize size and weight while having sufficient load capacity to support the forces on the impeller. Flux levels in the range of 0.1 T are employed in the magnetic bearings. Self sensing electronic circuits (without physical sensors) are employed to determine the impellar position and provide the feedback control signal needed for the magnetic bearing control loops. The sensors provide position sensitivity of approximately 0.025 mm. A decentralized 5 axis controller has been developed using modal control techniques. Proportional integral derivative controls are used for each axis to levitate the magnetically supported impeller.

  3. Performance study of microfluidic devices for blood plasma separation—a designer’s perspective

    NASA Astrophysics Data System (ADS)

    Tripathi, Siddhartha; Bala Varun Kumar, Y. V.; Prabhakar, Amit; Joshi, Suhas S.; Agrawal, Amit

    2015-08-01

    In this work, design and experiments on various blood plasma microdevices based on hydrodynamic flow separation techniques is carried out. We study their performance as a function of dependent governing parameters such as flow rate, feed hematocrit, and microchannel geometry. This work focuses on understanding separation phenomena in simple geometries; subsequently, individual simple geometrical parameters and biophysical effects are combined to fabricate hybridized designs, resulting in higher separation efficiencies. The distinctive features of our microfluidic devices are that they employ elevated dimensions (of the order of hundreds of microns), and thereby can be operated continuously over sufficient duration without clogging, while simplicity of fabrication makes them cost effective. The microdevices have been experimentally demonstrated over the entire range of hematocrit (i.e. from Hct 7% to Hct 45%). A high separation efficiency of about (78.34  ±  2.7)% with pure blood is achieved in our best hybrid design. We believe that the theory and experimental results presented in this study will aid designers and researchers working in the field of blood plasma separation microdevices.

  4. Advanced Aerodynamic Devices to Improve the Performance, Economics, Handling, and Safety of Heavy Vehicles

    SciTech Connect

    Robert J. Englar

    2001-05-14

    Research is being conducted at the Georgia Tech Research Institute (GTRI) to develop advanced aerodynamic devices to improve the performance, economics, stability, handling and safety of operation of Heavy Vehicles by using previously-developed and flight-tested pneumatic (blown) aircraft technology. Recent wind-tunnel investigations of a generic Heavy Vehicle model with blowing slots on both the leading and trailing edges of the trailer have been conducted under contract to the DOE Office of Heavy Vehicle Technologies. These experimental results show overall aerodynamic drag reductions on the Pneumatic Heavy Vehicle of 50% using only 1 psig blowing pressure in the plenums, and over 80% drag reductions if additional blowing air were available. Additionally, an increase in drag force for braking was confirmed by blowing different slots. Lift coefficient was increased for rolling resistance reduction by blowing only the top slot, while downforce was produced for traction increase by blowing only the bottom. Also, side force and yawing moment were generated on either side of the vehicle, and directional stability was restored by blowing the appropriate side slot. These experimental results and the predicted full-scale payoffs are presented in this paper, as is a discussion of additional applications to conventional commercial autos, buses, motor homes, and Sport Utility Vehicles.

  5. How Does the Driver’s Perception Reaction Time Affect the Performances of Crash Surrogate Measures?

    PubMed Central

    Kuang, Yan; Qu, Xiaobo; Weng, Jinxian; Etemad-Shahidi, Amir

    2015-01-01

    With the merit on representing traffic conflict through examining the crash mechanism and causality proactively, crash surrogate measures have long been proposed and applied to evaluate the traffic safety. However, the driver’s Perception-Reaction Time (PRT), an important variable in crash mechanism, has not been considered widely into surrogate measures. In this regard, it is important to know how the PRT affects the performances of surrogate indicators. To this end, three widely used surrogate measures are firstly modified by involving the PRT into their crash mechanisms. Then, in order to examine the difference caused by the PRT, a comparative study is carried out on a freeway section of the Pacific Motorway, Australia. This result suggests that the surrogate indicators’ performances in representing rear-end crash risks are improved with the incorporating of the PRT for the investigated section. PMID:26398416

  6. Female athletes: a population at risk of vitamin and mineral deficiencies affecting health and performance.

    PubMed

    McClung, James P; Gaffney-Stomberg, Erin; Lee, Jane J

    2014-10-01

    Adequate vitamin and mineral status is essential for optimal human health and performance. Female athletes could be at risk for vitamin and mineral insufficiency due to inadequate dietary intake, menstruation, and inflammatory responses to heavy physical activity. Recent studies have documented poor iron status and associated declines in both cognitive and physical performance in female athletes. Similarly, insufficient vitamin D and calcium status have been observed in female athletes, and may be associated with injuries, such as stress fracture, which may limit a female athlete's ability to participate in regular physical activity. This review will focus on recent studies detailing the prevalence of poor vitamin and mineral status in female athletes, using iron, vitamin D, and calcium as examples. Factors affecting the dietary requirement for these vitamins and minerals during physical training will be reviewed. Lastly, countermeasures for the prevention of inadequate vitamin and mineral status will be described.

  7. Chemical and physical parameters affecting the performance of the Os-191/Ir-191m generator

    SciTech Connect

    Packard, A.B.; Treves, S.; O'Brien, G.M.; Knapp, F.F. Jr.; Butler, T.A.

    1984-01-01

    The development of an Os-191/Ir-191m generator suitable for radionuclide angiography in humans has elicited much interest. This generator employs (OsO/sub 2/Cl/sub 4/)/sup 2 -/ on AG MP-1 anion exchange resin with a Dowex-2 scavenger column and is elute with normal saline at pH 1. The parent Os species is, however, neither well-defined nor homogeneous leading to less than optimal breakthrough of Os-191 (5 x 10/sup -3/%) and modest Ir-191m yield (10-15%). The effect of a range of parameters on generator performance has been evaluated as has been the way in which the assembly and loading process affects generator performance. In addition, a number of potential alternative generator systems have been evaluated. 11 references, 2 figures, 8 tables.

  8. Performance and management of implantable lithium battery systems for left ventricular assist devices and total artificial hearts

    NASA Astrophysics Data System (ADS)

    Dodd, J.; Kishiyama, C.; Mukainakano, Hiroshi; Nagata, M.; Tsukamoto, H.

    A lithium ion cell designed for implantable medical devices was tested for its performance as a power source for left ventricular assist devices (LVAD) or total artificial hearts (TAH). These two cardiovascular devices require high power, and thus a high current (0.5-3 A) and high voltage (20-30 V). Since these are implantable medical devices, in addition to high power capability, the power source should have long cycle life and calendar life, as well as high safety. The QL0700I, a 700 mAh cell, was cycled at 0.5 C rate as well as at 1.5 C rate, and the cycle life capacity retention was evaluated after numerous cycles. A battery pack consisting of seven QL0700I cells in series, with a battery management system (BMS) connected, was tested for rate capability as well as safety protection.

  9. A robotic device with a passive undulating ribbon fin: kinematics and propulsive performance

    NASA Astrophysics Data System (ADS)

    Liu, Hanlin; Curet, Oscar

    2015-11-01

    Many aquatic animals swim with high maneuverability using undulating ribbon fins. In this type of swimming, the organism propels by sending one or multiple traveling waves along an elongated fin. In previous work, robotic models with fully actuated fins where the parameters of the traveling waves are fully prescribed have been used to study the propulsive performance and fluid dynamics of this type of propulsion. However, less work has been done in ribbon fins with passively undulating waves. In this work, we use a robotic device to study the kinematics and propulsive performance of a passively undulating ribbon fin. The physical model is composed of fifteen rays interconnected with a membrane. Only two rays are actuated while the other rays are free to rotate through a common axis. The robotic fin was tested in a flume at different flow conditions. In a series of experiments we measured fin kinematics, propulsive forces and power consumption. As the leading two rays are actuated, a traveling wave with decaying amplitude passes through the passive rays. As the frequency of the actuated rays increases, the enclosed area of the undulating wave and the traveling wave frequency increase while the wavelength decreases. Our data also show that the propulsive force generated by the fin scaled with the enclosed area and the square of the relative velocity between incoming flow and traveling wave. These results suggest that both natural swimmers and underwater vehicles using ribbon-fin-based propulsion can potentially take advantage of passive undulating waves. National Science Foundation Grant No. 1420774

  10. Device performance and lifetime of polymer:fullerene solar cells with UV-ozone-irradiated hole-collecting buffer layers.

    PubMed

    Lee, Seungsoo; Nam, Sungho; Lee, Hyena; Kim, Hwajeong; Kim, Youngkyoo

    2011-11-18

    We report the influence of UV-ozone irradiation of the hole-collecting buffer layers on the performance and lifetime of polymer:fullerene solar cells. UV-ozone irradiation was targeted at the surface of the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layers by varying the irradiation time up to 600 s. The change of the surface characteristics in the PEDOT:PSS after UV-ozone irradiation was measured by employing optical absorption spectroscopy, photoelectron yield spectroscopy, and contact angle measurements, while Raman and X-ray photoelectron spectroscopy techniques were introduced for more microscopic analysis. Results showed that the UV-ozone irradiation changed the chemical structure/composition of the surface of the PEDOT:PSS layers leading to the gradual increase of ionization potential with irradiation time in the presence of up-and-down variations in the contact angle (polarity). This surface property change was attributed to the formation of oxidative components, as evidenced by XPS and Auger electron images, which affected the sheet resistance of the PEDOT:PSS layers. Interestingly, device performance was slightly improved by short irradiation (up to 10 s), whereas it was gradually decreased by further irradiation. The short-duration illumination test showed that the lifetime of solar cells with the UV-ozone irradiated PEDOT:PSS layer was improved due to the protective role of the oxidative components formed upon UV-ozone irradiation against the attack of sulfonic acid groups in the PEDOT:PSS layer to the active layer.

  11. An assessment of the Value of Certain Measuring Devices for Identifying Creative Writing Performance.

    ERIC Educational Resources Information Center

    Taylor, J. Lewis

    The purposes of this study were to assess the individual and relative value of seven types of measuring devices for identifying students with creative writing ability, also to determine which of the devices comprised the best small predictor battery for indicating creative talent. Of the nearly thirty "predictor" variable scores derived from the…

  12. Analysis and experimental study on the effect of a resonant tube on the performance of acoustic levitation devices

    NASA Astrophysics Data System (ADS)

    Jiang, Hai; Liu, Jianfang; Lv, Qingqing; Gu, Shoudong; Jiao, Xiaoyang; Li, Minjiao; Zhang, Shasha

    2016-09-01

    The influence of a resonant tube on the performance of acoustic standing wave-based levitation device (acoustic levitation device hereinafter) is studied by analyzing the acoustic pressure and levitation force of four types of acoustic levitation devices without a resonance tube and with resonance tubes of different radii R using ANSYS and MATLAB. Introducing a resonance tube either enhances or weakens the levitation strength of acoustic levitation device, depending on the resonance tube radii. Specifically, the levitation force is improved to a maximum degree when the resonance tube radius is slightly larger than the size of the reflector end face. Furthermore, the stability of acoustic levitation device is improved to a maximum degree by introducing a resonance tube of R=1.023λ. The experimental platform and levitation force measurement system of the acoustic levitation device with concave-end-face-type emitter and reflector are developed, and the test of suspended matters and liquid drops is conducted. Results show that the Φ6.5-mm steel ball is suspended easily when the resonance tube radius is 1.023λ, and the Φ5.5-mm steel ball cannot be suspended when the resonance tube radius is 1.251λ. The levitation capability of the original acoustic levitation device without a resonance tube is weakened when a resonance tube of R=1.251λ is applied. These results are consistent with the ANSYS simulation results. The levitation time of the liquid droplet with a resonance tube of R=1.023λ is longer than without a resonance tube. This result is also supported by the MATLAB simulation results. Therefore, the performance of acoustic levitation device can be improved by introducing a resonant tube with an appropriate radius.

  13. Performances of Different Global Positioning System Devices for Time-Location Tracking in Air Pollution Epidemiological Studies

    PubMed Central

    Wu, Jun; Jiang, Chengsheng; Liu, Zhen; Houston, Douglas; Jaimes, Guillermo; McConnell, Rob

    2010-01-01

    Background: People’s time-location patterns are important in air pollution exposure assessment because pollution levels may vary considerably by location. A growing number of studies are using global positioning systems (GPS) to track people’s time-location patterns. Many portable GPS units that archive location are commercially available at a cost that makes their use feasible for epidemiological studies. Methods: We evaluated the performance of five portable GPS data loggers and two GPS cell phones by examining positional accuracy in typical locations (indoor, outdoor, in-vehicle) and factors that influence satellite reception (building material, building type), acquisition time (cold and warm start), battery life, and adequacy of memory for data storage. We examined stationary locations (eg, indoor, outdoor) and mobile environments (eg, walking, traveling by vehicle or bus) and compared GPS locations to highly-resolved US Geological Survey (USGS) and Digital Orthophoto Quarter Quadrangle (DOQQ) maps. Results: The battery life of our tested instruments ranged from <9 hours to 48 hours. The acquisition of location time after startup ranged from a few seconds to >20 minutes and varied significantly by building structure type and by cold or warm start. No GPS device was found to have consistently superior performance with regard to spatial accuracy and signal loss. At fixed outdoor locations, 65%–95% of GPS points fell within 20-m of the corresponding DOQQ locations for all the devices. At fixed indoor locations, 50%–80% of GPS points fell within 20-m of the corresponding DOQQ locations for all the devices except one. Most of the GPS devices performed well during commuting on a freeway, with >80% of points within 10-m of the DOQQ route, but the performance was significantly impacted by surrounding structures on surface streets in highly urbanized areas. Conclusions: All the tested GPS devices had limitations, but we identified several devices which showed

  14. Cognition-Based and Affect-Based Trust as Mediators of Leader Behavior Influences on Team Performance

    ERIC Educational Resources Information Center

    Schaubroeck, John; Lam, Simon S. K.; Peng, Ann Chunyan

    2011-01-01

    We develop a model in which cognitive and affective trust in the leader mediate the relationship between leader behavior and team psychological states that, in turn, drive team performance. The model is tested on a sample of 191 financial services teams in Hong Kong and the U.S. Servant leadership influenced team performance through affect-based…

  15. Ambient temperature: a factor affecting performance and physiological response of broiler chickens

    NASA Astrophysics Data System (ADS)

    Donkoh, A.

    1989-12-01

    An experiment was conducted to elucidate the influence of four constant ambient temperatures (20°, 25°, 30° and 35°C) on the performance and physiological reactions of male commercial broiler chicks from 3 to 7 weeks of age. A 12 h light-dark cycle was operated, while relative humidity and air circulation were not controlled. Exposure of broiler chickens to the 20°, 25°, 30° and 35°C treatments showed highly significant ( P<0.0001) depression in growth rate, food intake and efficiency of food utilization, and a significant increase in water consumption for the 30° and 35°C groups. Mortality was, however, not affected by the temperature treatments. Changes in physiological status, such as increased rectal temperatures, decreased concentration of red blood cells, haemoglobin, haematocrit, and total plasma protein were observed in birds housed in the higher temperature (30° and 35°C) environments. Moreover, in these broiler chickens, there was an increased blood glucose concentration and a decreased thyroid gland weight. These results indicate that continuous exposure of broiler chickens to high ambient temperatures markedly affects their performance and physiological response.

  16. The effect of cognitive status and visuospatial performance on affective theory of mind in Parkinson's disease.

    PubMed

    McKinlay, Audrey; Albicini, Michelle; Kavanagh, Phillip S

    2013-01-01

    It is now well accepted that theory of mind (ToM) functioning is impaired in Parkinson's disease (PD) patients. However, what remain unknown are the functions that underlie this impairment. It has been suggested that cognitive skills may be key in this area of functioning; however, many of the cognitive tests used to assess this have relied on intact visuospatial abilities. This study aimed to examine whether deficits in ToM were generated by cognitive or visuospatial dysfunction and the mediating effect of visuospatial function on ToM performance. Fifty PD patients (31 male, 19 female; mean age = 66.34 years) and 49 healthy controls (16 male, 33 female; mean age = 67.29 years) completed a ToM task (reading the mind in the eyes) and visuospatial task (line orientation). The results revealed that current cognitive status was a significant predictor for performance on the ToM task, and that 54% of the total effect of cognitive status on ToM was mediated by visuospatial abilities. It was concluded that visuospatial functioning plays an important mediating role for the relationship between executive dysfunction and affective ToM deficits in PD patients, and that visuospatial deficits may directly contribute to the presence of affective ToM difficulties seen in individuals with PD.

  17. A training paradigm to enhance performance and safe use of an innovative neuroendovascular device.

    PubMed

    Ricci, Donald R; Marotta, Thomas R; Riina, Howard A; Wan, Martina; De Vries, Joost

    2016-01-01

    Training has been important to facilitate the safe use of new devices designed to repair vascular structures. This paper outlines the generic elements of a training program for vascular devices and uses as an example the actual training requirements for a novel device developed for the treatment of bifurcation intracranial aneurysms. Critical elements of the program include awareness of the clinical problem, technical features of device, case selection, and use of a simulator. Formal proctoring, evaluation of the training, and recording the clinical outcomes complement these elements. Interventional physicians should embrace the merits of a training module to improve the user experience, and vendors, physicians, and patients alike should be aligned in the goal of device training to improve its success rate and minimize complications of the procedure.

  18. A training paradigm to enhance performance and safe use of an innovative neuroendovascular device

    PubMed Central

    Ricci, Donald R.; Marotta, Thomas R.; Riina, Howard A.; Wan, Martina; De Vries, Joost

    2016-01-01

    Training has been important to facilitate the safe use of new devices designed to repair vascular structures. This paper outlines the generic elements of a training program for vascular devices and uses as an example the actual training requirements for a novel device developed for the treatment of bifurcation intracranial aneurysms. Critical elements of the program include awareness of the clinical problem, technical features of device, case selection, and use of a simulator. Formal proctoring, evaluation of the training, and recording the clinical outcomes complement these elements. Interventional physicians should embrace the merits of a training module to improve the user experience, and vendors, physicians, and patients alike should be aligned in the goal of device training to improve its success rate and minimize complications of the procedure. PMID:27867466

  19. Water consumption, not expectancies about water consumption, affects cognitive performance in adults.

    PubMed

    Edmonds, Caroline J; Crombie, Rosanna; Ballieux, Haiko; Gardner, Mark R; Dawkins, Lynne

    2013-01-01

    Research has shown that water supplementation positively affects cognitive performance in children and adults. The present study considered whether this could be a result of expectancies that individuals have about the effects of water on cognition. Forty-seven participants were recruited and told the study was examining the effects of repeated testing on cognitive performance. They were assigned either to a condition in which positive expectancies about the effects of drinking water were induced, or a control condition in which no expectancies were induced. Within these groups, approximately half were given a drink of water, while the remainder were not. Performance on a thirst scale, letter cancellation, digit span forwards and backwards and a simple reaction time task was assessed at baseline (before the drink) and 20 min and 40 min after water consumption. Effects of water, but not expectancy, were found on subjective thirst ratings and letter cancellation task performance, but not on digit span or reaction time. This suggests that water consumption effects on letter cancellation are due to the physiological effects of water, rather than expectancies about the effects of drinking water.

  20. Altitude affects the reproductive performance in monoicous and dioicous bryophytes: examples from a Brazilian Atlantic rainforest

    PubMed Central

    Maciel-Silva, Adaíses S.; Marques Valio, Ivany F.; Rydin, Håkan

    2012-01-01

    Background and aims Short life cycles and trade-offs linked to breeding systems make bryophytes good models for the study of plant reproductive strategies. Our aim was to test if differences in sexual reproductive performance of bryophytes in tropical rainforests are driven by the breeding system of the species (monoicous or dioicous) or are mainly affected by the habitat. Methodology The reproductive performance (sexual branches, gametangia (sex organs), fertilization and sporophyte production) of 11 species was repeatedly monitored and analysed from populations at sea-level and montane sites of a Brazilian Atlantic rainforest over 15 months. Principal results Monoicous species had the highest reproductive performance, particularly for sexual branches, fertilized gametangia and sporophyte production. Species at the sea-level site produced more sexual branches and had more female-biased sex ratios of gametangia than species in the montane site. Fertilizations were more frequent at the montane site, but sporophyte frequency was similar between the two sites. Fertilization tended to occur mostly in the periods of heavy rain (October to December). Conclusions Breeding system is not the only major influence on the reproductive performance of bryophytes. We show that habitat is also an important factor determining life-history differentiation. Female-biased sex ratios and low rates of fertilization are seen to be compensated for by high production of reproductive structures at the initial phases of the reproductive cycle. PMID:22822422

  1. Germanium-on-Silicon Strain Engineered Materials for Improved Device Performance Grown by Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Bharathan, Jayesh Moorkoth

    present during epitaxy. The microstructural characteristics of Ge films were analyzed by x-ray diffraction, atomic force microscopy and transmission electron microscopy. The principal defects in the epitaxial films were determined to be threading dislocations and stacking faults. A unique defect appearing as a line during defect delineation was established to be a wide stacking fault arising from oxygen contamination during RPCVD epitaxy. A decrease in defect density by almost an order of magnitude was observed with increasing film thickness. Germanium films with a thickness of 3.5 mum exhibited the lowest threading dislocation densities of 5 x 106 cm-2. The mechanisms of interactions between threading dislocations has been discussed with the aid of transmission electron microscopy to explain the reduction in the observed threading dislocation density. A strong correlation was obtained between electrical performance of the devices and defect density. Thicker films with the lowest threading dislocation density of 5 x 106 cm-2 also yielded devices with the lowest dark current density of ˜ 5 mA/cm2 (1 V reverse bias) and bulk resistivity of 30 O cm2. All devices showed spectral response of up to 1.61 mum, confirming a strain-induced shrinkage of the direct band gap by approximately 30 meV, which is in good agreement with theoretical models. In summary, the structural, electrical, and optical properties of 2-D Ge films grown on Si(001) substrates by RPCVD has been investigated.

  2. Blood collection tubes as medical devices: The potential to affect assays and proposed verification and validation processes for the clinical laboratory.

    PubMed

    Bowen, Raffick A R; Adcock, Dorothy M

    2016-12-01

    Blood collection tubes (BCTs) are an often under-recognized variable in the preanalytical phase of clinical laboratory testing. Unfortunately, even the best-designed and manufactured BCTs may not work well in all clinical settings. Clinical laboratories, in collaboration with healthcare providers, should carefully evaluate BCTs prior to putting them into clinical use to determine their limitations and ensure that patients are not placed at risk because of inaccuracies due to poor tube performance. Selection of the best BCTs can be achieved through comparing advertising materials, reviewing the literature, observing the device at a scientific meeting, receiving a demonstration, evaluating the device under simulated conditions, or testing the device with patient samples. Although many publications have discussed method validations, few detail how to perform experiments for tube verification and validation. This article highlights the most common and impactful variables related to BCTs and discusses the validation studies that a typical clinical laboratory should perform when selecting BCTs. We also present a brief review of how in vitro diagnostic devices, particularly BCTs, are regulated in the United States, the European Union, and Canada. The verification and validation of BCTs will help to avoid the economic and human costs associated with incorrect test results, including poor patient care, unnecessary testing, and delays in test results. We urge laboratorians, tube manufacturers, diagnostic companies, and other researchers to take all the necessary steps to protect against the adverse effects of BCT components and their additives on clinical assays.

  3. Red Color Light at Different Intensities Affects the Performance, Behavioral Activities and Welfare of Broilers.

    PubMed

    Senaratna, D; Samarakone, T S; Gunawardena, W W D A

    2016-07-01

    Red light (RL) marked higher weight gain (WG) and preference of broilers compared to other light colors. This study aimed to investigate how different intensities of RL affect the performance, behavior and welfare of broilers. RL treatments were T1 = high intensity (320 lux), T2 = medium intensity (20 lux); T3 = dim intensity (5 lux), T4 = control/white light at (20 lux) provided on 20L:4D schedule and T5 = negative control; 12 hours dark: 12 hours day light. Cobb strain broilers were used in a Complete Randomize Design with 6 replicates. WG, water/feed intake, feed conversion ratio (FCR), mortality, behavior and welfare were assessed. At 35 d, significantly (p<0.05) highest body weight (2,147.06 g±99) was recorded by T3. Lowest body weight (1,640.55 g±56) and FCR (1.34) were recorded by T5. Skin weight was the only carcass parameter showed a significant (p<0.05) influence giving the highest (56.2 g) and the lowest (12.6 g) values for T5 and T1 respectively. Reduced welfare status indicated by significantly (p<0.05) higher foot pad lesions, hock burns and breast blisters was found under T3, due to reduced expression of behavior. Highest walking (2.08%±1%) was performed under T1 in the evening during 29 to 35 days. Highest dust bathing (3.01%±2%) was performed in the morning during 22 to 28 days and highest bird interaction (BI) (4.87%±4%) was observed in the evening by T5 during 14 to 21 days. Light intensity×day session×age interaction was significantly (p<0.05) affected walking, dust bathing and BI. Light intensity significantly (p<0.05) affected certain behaviors such as lying, eating, drinking, standing, walking, preening while lying, wing/leg stretching, sleeping, dozing, BI, vocalization, idling. In conclusion, birds essentially required provision of light in the night for better performance. Exposed to 5 lux contributed to higher WG, potentially indicating compromised welfare status. Further researches are suggested to investigate RL intensity based

  4. Low-temperature phase transitions in a soluble oligoacene and their effect on device performance and stability

    SciTech Connect

    Ward, J. W.; Goetz, K. P.; Obaid, A.; Diemer, P. J.; Jurchescu, O. D.; Payne, M. M.; Anthony, J. E.; Day, C. S.

    2014-08-25

    The use of organic semiconductors in high-performance organic field-effect transistors requires a thorough understanding of the effects that processing conditions, thermal, and bias-stress history have on device operation. Here, we evaluate the temperature dependence of the electrical properties of transistors fabricated with 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene, a material that has attracted much attention recently due to its exceptional electrical properties. We have discovered a phase transition at T = 205 K and discuss its implications on device performance and stability. We examined the impact of this low-temperature phase transition on the thermodynamic, electrical, and structural properties of both single crystals and thin films of this material. Our results show that while the changes to the crystal structure are reversible, the induced thermal stress yields irreversible degradation of the devices.

  5. Dietary electrolyte balance affects growth performance, amylase activity and metabolic response in the meagre (Argyrosomus regius).

    PubMed

    Magnoni, Leonardo J; Salas-Leiton, Emilio; Peixoto, Maria-João; Pereira, Luis; Silva-Brito, Francisca; Fontinha, Filipa; Gonçalves, José F M; Wilson, Jonathan M; Schrama, Johan W; Ozório, Rodrigo O A

    2017-03-16

    Dietary ion content is known to alter the acid-base balance in freshwater fish. The current study investigated the metabolic impact of acid-base disturbances produced by differences in dietary electrolyte balance (DEB) in the meagre (Argyrosomus regius), an euryhaline species. Changes in fish performance, gastric chyme characteristics, pH and ion concentrations in the bloodstream, digestive enzyme activities and metabolic rates were analyzed in meagre fed ad libitum two experimental diets (DEB 200 or DEB 700mEq/kg) differing in the Na2CO3 content for 69days. Fish fed the DEB 200 diet had 60-66% better growth performance than the DEB 700 group. Meagre consuming the DEB 200 diet were 90-96% more efficient than fish fed the DEB 700 diet at allocating energy from feed into somatic growth. The pH values in blood were significantly lower in the DEB 700 group 2h after feeding when compared to DEB 200, indicating that acid-base balance in meagre was affected by electrolyte balance in diet. Osmolality, and Na(+) and K(+) concentrations in plasma did not vary with the dietary treatment. Gastric chyme in the DEB 700 group had higher pH values, dry matter, protein and energy contents, but lower lipid content than in the DEB 200 group. Twenty-four hours after feeding, amylase activity was higher in the gastrointestinal tract of DEB 700 group when compared to the DEB 200 group. DEB 700 group had lower routine metabolic (RMR) and standard metabolic (SMR) rates, indicating a decrease in maintenance energy expenditure 48h after feeding the alkaline diet. The current study demonstrates that feeding meagre with an alkaline diet not only causes acid-base imbalance, but also negatively affects digestion and possibly nutrient assimilation, resulting in decreased growth performance.

  6. Decomposers (Lumbricidae, Collembola) affect plant performance in model grasslands of different diversity.

    PubMed

    Partsch, Stephan; Milcu, Alexandru; Scheu, Stefan

    2006-10-01

    Decomposer invertebrates influence soil structure and nutrient mineralization as well as the activity and composition of the microbial community in soil and therefore likely affect plant performance and plant competition. We established model grassland communities in a greenhouse to study the interrelationship between two different functional groups of decomposer invertebrates, Lumbricidae and Collembola, and their effect on plant performance and plant nitrogen uptake in a plant diversity gradient. Common plant species of Central European Arrhenatherion grasslands were transplanted into microcosms with numbers of plant species varying from one to eight and plant functional groups varying from one to four. Separate and combined treatments with earthworms and collembolans were set up. Microcosms contained 15N labeled litter to track N fluxes into plant shoots. Presence of decomposers strongly increased total plant and plant shoot biomass. Root biomass decreased in the presence of collembolans and even more in the presence of earthworms. However, it increased when both animal groups were present. Also, presence of decomposers increased total N concentration and 15N enrichment of grasses, legumes, and small herbs. Small herbs were at a maximum in the combined treatment with earthworms and collembolans. The impact of earthworms and collembolans on plant performance strongly varied with plant functional group identity and plant species diversity and was modified when both decomposers were present. Both decomposer groups generally increased aboveground plant productivity through effects on litter decomposition and nutrient mineralization leading to an increased plant nutrient acquisition. The non-uniform effects of earthworms and collembolans suggest that functional diversity of soil decomposer animals matters and that the interactions between soil animal functional groups affect the structure of plant communities.

  7. Investigation of thioglycerol stabilized ZnS quantum dots in electroluminescent device performance

    NASA Astrophysics Data System (ADS)

    Ethiraj, Anita Sagadevan; Rhen, Dani; Lee, D. H.; Kang, Dae Joon; Kulkarni, S. K.

    2016-05-01

    The present work is focused on the investigation of thioglycerol (TG) stabilized Zinc Sulfide Quantum dots (ZnS QDs) in the hybrid electroluminescence (EL) device. Optical absorption spectroscopy clearly indicates the formation of narrow size distributed ZnS in the quantum confinement regime. X-ray Diffraction (XRD), Photoluminescence (PL), Energy Dispersive X-ray Spectroscopy (EDS) data supports the same. The hybrid EL device with structure of ITO (indium tin oxide)//PEDOT:PSS ((poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)//HTL (α NPD- N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-phenyl)-4,4'-diamine// PVK:ZnS QDs//ETL(PBD- 2-tert-butylphenyl- 5-biphenyl-1,3,4-oxadiazole)//LiF:Al (Device 1) was fabricated. Reference device without the ZnS QDs were also prepared (Device 2). The results show that the ZnS QDs based device exhibited bright electroluminescence emission of 24 cd/m2 at a driving voltage of 16 Volts under the forward bias conditions as compared to the reference device without the ZnS QDs, which showed 6 cd/m2 at ˜22 Volts.

  8. Design and performance of a respiratory amplitude gating device for PET/CT imaging

    SciTech Connect

    Chang Guoping; Chang Tingting; Clark, John W. Jr.; Mawlawi, Osama R.

    2010-04-15

    Purpose: Recently, the authors proposed a free-breathing amplitude gating (FBAG) technique for PET/CT scanners. The implementation of this technique required specialized hardware and software components that were specifically designed to interface with commercial respiratory gating devices to generate the necessary triggers required for the FBAG technique. The objective of this technical note is to introduce an in-house device that integrates all the necessary hardware and software components as well as tracks the patient's respiratory motion to realize amplitude gating on PET/CT scanners. Methods: The in-house device is composed of a piezoelectric transducer coupled to a data-acquisition system in order to monitor the respiratory waveform. A LABVIEW program was designed to control the data-acquisition device and inject triggers into the PET list stream whenever the detected respiratory amplitude crossed a predetermined amplitude range. A timer was also programmed to stop the scan when the accumulated time within the selected amplitude range reached a user-set interval. This device was tested using a volunteer and a phantom study. Results: The results from the volunteer and phantom studies showed that the in-house device can detect similar respiratory signals as commercially available respiratory gating systems and is able to generate the necessary triggers to suppress respiratory motion artifacts. Conclusions: The proposed in-house device can be used to implement the FBAG technique in current PET/CT scanners.

  9. Subsonic Maneuvering Effectiveness of High Performance Aircraft Which Employ Quasi-Static Shape Change Devices

    NASA Technical Reports Server (NTRS)

    Montgomery, Raymond C.; Scott, Michael A.; Weston, Robert P.

    1998-01-01

    This paper represents an initial study on the use of quasi-static shape change devices in aircraft maneuvering. The macroscopic effects and requirements for these devices in flight control are the focus of this study. Groups of devices are postulated to replace the conventional leading-edge flap (LEF) and the all-moving wing tip (AMT) on the tailless LMTAS-ICE (Lockheed Martin Tactical Aircraft Systems - Innovative Control Effectors) configuration. The maximum quasi-static shape changes are 13.8% and 7.7% of the wing section thickness for the LEF and AMT replacement devices, respectively. A Computational Fluid Dynamics (CFD) panel code is used to determine the control effectiveness of groups of these devices. A preliminary design of a wings-leveler autopilot is presented. Initial evaluation at 0.6 Mach at 15,000 ft. altitude is made through batch simulation. Results show small disturbance stability is achieved, however, an increase in maximum distortion is needed to statically offset five degrees of sideslip. This only applies to the specific device groups studied, encouraging future research on optimal device placement.

  10. 49 CFR 232.405 - Design and performance standards for two-way end-of-train devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and perform with the following features: (a) An emergency brake application command from the front.... (b) The rear unit of the device shall send an acknowledgment message to the front unit immediately upon receipt of an emergency brake application command. The front unit shall listen for...

  11. 49 CFR 232.405 - Design and performance standards for two-way end-of-train devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... and perform with the following features: (a) An emergency brake application command from the front.... (b) The rear unit of the device shall send an acknowledgment message to the front unit immediately upon receipt of an emergency brake application command. The front unit shall listen for...

  12. Warming-Up Affects Performance and Lactate Distribution between Plasma and Red Blood Cells

    PubMed Central

    Wahl, Patrick; Zinner, Christoph; Yue, Zengyuan; Bloch, Wilhelm; Mester, Joachim

    2010-01-01

    Warming-up (WU) is a widely used preparation for training and competition. However, little is known about the potential mechanisms of WU on performance and on the lactate distribution in the blood compartment. The purpose of the present study was to investigate whether different WU procedures affect performance and lactate distribution between plasma and red blood cells (RBCs) after maximal exercise. At three different occasions eleven subjects performed one 30 s maximal effort exercise on a cycle ergometer. Before each exercise, subjects warmed up at different intensities: 1. no WU (NWU); 2. extensive WU (EWU); 3. intensive WU (IWU). Blood samples were taken under resting conditions, after WU, and in 1 minute intervals during recovery to determine lactate concentrations [LA] in whole blood ([LA]WB), plasma ([LA]plasma) and erythrocytes ([LA]RBC). Mean power output was +58 Watt (EWU) and +60 Watt (IWU) higher compared to NWU. For each WU condition [LA]plasma and [LA]RBC differed significantly at any time point, showing greater [LA]plasma compared to [LA]RBC. The maximal effort exercise caused a rapid decrease of the [LA]RBC/[LA]plasma ratio. [LA]RBC reached the peak 3-5 minutes later than [LA]plasma depending on the WU condition. The initial increments in [LA]RBC were 10-16% lower after IWU compared to NWU and EWU. The lower increment of [LA]RBC after IWU might be due to a “higher preloading” with lactate before exercise, causing a smaller initial [LA] gradient between plasma and RBCs. It seems that the influx decreases with increasing intracellular [LA]. Another possibility one could speculate about is, that the extracellular increase in [LA] inhibits the outflux of lactate produced by the RBC itself. This inhibited export of lactate from RBCs may lead to an intracellular lactate accumulation. But the relatively fast increase in [LA]RBC and other investigations partly contradicts this possibility. Key points Warm-up significantly improves performance during 30

  13. Adaptive cellular structures and devices with internal features for enhanced structural performance

    NASA Astrophysics Data System (ADS)

    Pontecorvo, Michael Eugene

    This dissertation aims to develop a family of cellular and repeatable devices that exhibit a variety of force-displacement behaviors. It is envisioned that these cellular structures might be used either as stand-alone elements, or combined and repeated to create multiple types of structures (i.e. buildings, ship hulls, vehicle subfloors, etc.) with the ability to passively or actively perform multiple functions (harmonic energy dissipation, impact mitigation, modulus change) over a range of loading types, amplitudes, and frequencies. To accomplish this goal, this work combines repeatable structural frameworks, such as that provided by a hexagonal cellular structure, with internal structural elements such as springs, viscous dampers, buckling plates, bi-stable von Mises trusses (VMTs), and pneumatic artificial muscles (PAMs). The repeatable framework serves to position damping and load carrying elements throughout the structure, and the configuration of the internal elements allow each cell to be tuned to exhibit a desired force-displacement response. Therefore, gradient structures or structures with variable load paths can be created for an optimal global response to a range of loads. This dissertation focuses on the development of cellular structures for three functions: combined load-carrying capability with harmonic energy dissipation, impact mitigation, and cell modulus variation. One or more conceptual designs are presented for devices that can perform each of these functions, and both experimental measurements and simulations are used to gain a fundamental understanding of each device. Chapter 2 begins with a presentation of a VMT model that is the basis for many of the elements. The equations of motion for the VMT are derived and the static and dynamic behavior of the VMT are discussed in detail. Next, two metrics for the energy dissipation of the VMT - hysteresis loop area and loss factor - are presented. The responses of the VMT to harmonic displacement

  14. Development of Pneumatic Aerodynamic Devices to Improve the Performance, Economics, and Safety of Heavy Vehicles

    SciTech Connect

    Robert J. Englar

    2000-06-19

    Under contract to the DOE Office of Heavy Vehicle Technologies, the Georgia Tech Research Institute (GTRI) is developing and evaluating pneumatic (blown) aerodynamic devices to improve the performance, economics, stability and safety of operation of Heavy Vehicles. The objective of this program is to apply the pneumatic aerodynamic aircraft technology previously developed and flight-tested by GTRI personnel to the design of an efficient blown tractor-trailer configuration. Recent experimental results obtained by GTRI using blowing have shown drag reductions of 35% on a streamlined automobile wind-tunnel model. Also measured were lift or down-load increases of 100-150% and the ability to control aerodynamic moments about all 3 axes without any moving control surfaces. Similar drag reductions yielded by blowing on bluff afterbody trailers in current US trucking fleet operations are anticipated to reduce yearly fuel consumption by more than 1.2 billion gallons, while even further reduction is possible using pneumatic lift to reduce tire rolling resistance. Conversely, increased drag and down force generated instantaneously by blowing can greatly increase braking characteristics and control in wet/icy weather due to effective ''weight'' increases on the tires. Safety is also enhanced by controlling side loads and moments caused on these Heavy Vehicles by winds, gusts and other vehicles passing. This may also help to eliminate the jack-knifing problem if caused by extreme wind side loads on the trailer. Lastly, reduction of the turbulent wake behind the trailer can reduce splash and spray patterns and rough air being experienced by following vehicles. To be presented by GTRI in this paper will be results developed during the early portion of this effort, including a preliminary systems study, CFD prediction of the blown flowfields, and design of the baseline conventional tractor-trailer model and the pneumatic wind-tunnel model.

  15. High-Performance Electrochromic Devices Based on Poly[Ni(salen)]-Type Polymer Films.

    PubMed

    Nunes, Marta; Araújo, Mariana; Fonseca, Joana; Moura, Cosme; Hillman, Robert; Freire, Cristina

    2016-06-08

    We report the application of two poly[Ni(salen)]-type electroactive polymer films as new electrochromic materials. The two films, poly[Ni(3-Mesalen)] (poly[1]) and poly[Ni(3-MesaltMe)] (poly[2]), were successfully electrodeposited onto ITO/PET flexible substrates, and their voltammetric characterization revealed that poly[1] showed similar redox profiles in LiClO4/CH3CN and LiClO4/propylene carbonate (PC), while poly[2] showed solvent-dependent electrochemical responses. Both films showed multielectrochromic behavior, exhibiting yellow, green, and russet colors according to their oxidation state, and promising electrochromic properties with high electrochemical stability in LiClO4/PC supporting electrolyte. In particular, poly[1] exhibited a very good electrochemical stability, changing color between yellow and green (λ = 750 nm) during 9000 redox cycles, with a charge loss of 34.3%, an optical contrast of ΔT = 26.2%, and an optical density of ΔOD = 0.49, with a coloration efficiency of η = 75.55 cm(2) C(-1). On the other hand, poly[2] showed good optical contrast for the color change from green to russet (ΔT = 58.5%), although with moderate electrochemical stability. Finally, poly[1] was used to fabricate a solid-state electrochromic device using lateral configuration with two figures of merit: a simple shape (typology 1) and a butterfly shape (typology 2); typology 1 showed the best performance with optical contrast ΔT = 88.7% (at λ = 750 nm), coloration efficiency η = 130.4 cm(2) C(-1), and charge loss of 37.0% upon 3000 redox cycles.

  16. Differences in Foliage Affect Performance of the Lappet Moth, Streblote panda: Implications for Species Fitness

    PubMed Central

    Calvo, D.; Molina, J.M.

    2010-01-01

    Implications for adults' fitness through the foliage effects of five different host plants on larval survival and performance of the lappet moth, Streblote panda Hübner (Lepidoptera: Lasiocampidae), as well as their effect on species fitness were assayed. Larvae were reared under controlled laboratory conditions on excised foliage. Long-term developmental experiments were done using first instar larvae to adult emergence, and performance experiments were done using fifth instar larvae. Survival, development rates, and food use were measured. Foliar traits analysis indicated that leaves of different host plants varied, significantly affecting larvae performance and adult fitness. Pistacia lentiscus L. (Sapindales: Anacardiaceae), Arbutus unedo L. (Ericales: Ericaceae), and Retama sphaerocarpa (L.) Boiss. (Fabales: Fabaceae) were the most suitable hosts. Larvae fed on Tamarix gallica L. (Caryophyllales: Tamaricaceae) and Spartium junceum L. (Fabales: Fabaceae) showed the lowest survival, rates of development and pupal and adult weight. In general, S. panda showed a relatively high capacity to buffer low food quality, by reducing developmental rates and larvae development thereby reaching the minimum pupal weight that ensures adult survival. Less suitable plants seem to have indirect effects on adult fitness, producing smaller adults that could disperse to other habitats. PMID:21062148

  17. Work-family enrichment and job performance: a constructive replication of affective events theory.

    PubMed

    Carlson, Dawn; Kacmar, K Michele; Zivnuska, Suzanne; Ferguson, Merideth; Whitten, Dwayne

    2011-07-01

    Based on affective events theory (AET), we hypothesize a four-step model of the mediating mechanisms of positive mood and job satisfaction in the relationship between work-family enrichment and job performance. We test this model for both directions of enrichment (work-to-family and family-to-work). We used two samples to test the model using structural equation modeling. Results from Study 1, which included 240 full-time employees, were replicated in Study 2, which included 189 matched subordinate-supervisor dyads. For the work-to-family direction, results from both samples support our conceptual model and indicate mediation of the enrichment-performance relationship for the work-to-family direction of enrichment. For the family-to-work direction, results from the first sample support our conceptual model but results from the second sample do not. Our findings help elucidate mixed findings in the enrichment and job performance literatures and contribute to an understanding of the mechanisms linking these concepts. We conclude with a discussion of the practical and theoretical implications of our findings.

  18. Performance of music elevates pain threshold and positive affect: implications for the evolutionary function of music.

    PubMed

    Dunbar, R I M; Kaskatis, Kostas; MacDonald, Ian; Barra, Vinnie

    2012-10-22

    It is well known that music arouses emotional responses. In addition, it has long been thought to play an important role in creating a sense of community, especially in small scale societies. One mechanism by which it might do this is through the endorphin system, and there is evidence to support this claim. Using pain threshold as an assay for CNS endorphin release, we ask whether it is the auditory perception of music that triggers this effect or the active performance of music. We show that singing, dancing and drumming all trigger endorphin release (indexed by an increase in post-activity pain tolerance) in contexts where merely listening to music and low energy musical activities do not. We also confirm that music performance results in elevated positive (but not negative) affect. We conclude that it is the active performance of music that generates the endorphin high, not the music itself. We discuss the implications of this in the context of community bonding mechanisms that commonly involve dance and music-making.

  19. Study of the relative performance of silicon and germanium nanoparticles embedded gate oxide in metal-oxide-semiconductor memory devices

    NASA Astrophysics Data System (ADS)

    Chakraborty, G.; Sengupta, A.; Requejo, F. G.; Sarkar, C. K.

    2011-03-01

    In the present work, we have investigated a comparative performance of the silicon (Si) and germanium (Ge) nanoparticles embedded SiO2 floating gate MOS memory devices. In such devices for low applied fields, the tunneling current is dominated by the direct tunneling mechanism, whereas for higher electric fields, the Fowler-Nordheim tunneling mechanism dominates. As the device dimensions get smaller, problem arises in the conventional MOS memory devices due to the leakage through the thin tunnel oxide. This leakage can be reduced via charge trapping by embedding nanoparticles in the gate dielectric of such devices. Here one objective is to prevent the leakage due to the direct tunneling mechanism and the other objective is to reduce the write voltage, by lowering the onset voltage of the Fowler-Nordheim tunneling mechanism. Our simulations for the current voltage characteristics covered both the low and the high applied field regions. Simulations showed that both the Si and the Ge nanoparticles embedded gate dielectrics offer reduction of the leakage current and a significant lowering of the writing or programming onset voltage, compared to the pure SiO2 gate dielectric. In terms of the comparative performance, the Germanium nanoparticles embedded gate dielectric showed better results compared to the silicon nanoparticles embedded one. The results of the simulations are discussed in the light of recent experimental results.

  20. High-performance spinning device for DVD-based micromechanical signal transduction

    NASA Astrophysics Data System (ADS)

    Hwu, En-Te; Chen, Ching-Hsiu; Bosco, Filippo G.; Wang, Wei-Min; Ko, Hsien-Chen; Hwang, Ing-Shouh; Boisen, Anja; Huang, Kuang-Yuh

    2013-04-01

    Here we report a high-throughput spinning device for nanometric scale measurements of microstructures with instrumentation details and experimental results. The readout technology implemented in the designed disc-like device is based on a DVD data storage optical pick-up unit (OPU). With a spinning mechanism, this device can simultaneously measure surface topography, mechanical deflections and resonance frequencies of several microfabricated beams at a high speed. In biochemical sensing applications, the OPU can measure bending changes of functionalized microcantilevers, providing a statistically robust and label-free bio-detection analysis of multiple compounds. The signal-to-noise ratio (S/N) is demonstrated from statistical measurements as 1.2 with arginine detection at 750 nM concentration. Practically, the OPU can measure up to 480 individual cantilever sensors per second with nanometer resolution. The opto-mechanical optimization of the device design and settings for biochemical detection are described.

  1. Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.

    PubMed

    Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

    2013-10-04

    Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry.

  2. An investigation of the performance of novel chorded keyboards in combination with pointing input devices.

    PubMed

    Shi, Wen-Zhou; Wu, Fong-Gong

    2015-01-01

    Rapid advances in computing power have driven the development of smaller and lighter technology products, with novel input devices constantly being produced in response to new user behaviors and usage contexts. The aim of this research was to investigate the feasibility of operating chorded keyboard control modules in concert with pointing devices such as styluses and mice. We compared combinations of two novel chorded keyboards with different pointing devices in hopes of finding a better combination for future electronic products. Twelve participants were recruited for simulation testing, and paired sample t testing was conducted to determine whether input and error rates for the novel keyboards were improved significantly over those of traditional input methods. The most efficient input device combination tested was the combination of a novel cross-shaped key keyboard and a stylus, suggesting the high potential for use of this combination with future mobile IT products.

  3. Negative differential resistance and rectifying performance induced by doped graphene nanoribbons p-n device

    NASA Astrophysics Data System (ADS)

    Zhou, Yuhong; Qiu, Nianxiang; Li, Runwei; Guo, Zhansheng; Zhang, Jian; Fang, Junfeng; Huang, Aisheng; He, Jian; Zha, Xianhu; Luo, Kan; Yin, Jingshuo; Li, Qiuwu; Bai, Xiaojing; Huang, Qing; Du, Shiyu

    2016-03-01

    Employing nonequilibrium Green's Functions in combination with density functional theory, the electronic transport properties of armchair graphene nanoribbon (GNR) devices with various widths are investigated in this work. In the adopted model, two semi-infinite graphene electrodes are periodically doped with boron or nitrogen atoms. Our calculations reveal that these devices have a striking nonlinear feature and show notable negative differential resistance (NDR). The results also indicate the diode-like properties are reserved and the rectification ratios are high. It is found the electronic transport properties are strongly dependent on the width of doped nanoribbons and the positions of dopants and three distinct families are elucidated for the current armchair GNR devices. The NDR as well as rectifying properties can be well explained by the variation of transmission spectra and the relative shift of discrete energy states with applied bias voltage. These findings suggest that the doped armchair GNR is a promising candidate for the next generation nanoscale device.

  4. Performance and acceptability of a combined device for insulin infusion and glucose sensing in the home setting.

    PubMed

    Nørgaard, Kirsten; Shin, John; Welsh, John B; Gjessing, Hans

    2015-03-01

    The use of sensor-augmented insulin pump (SAP) therapy is increasing. Currently, glucose sensors and insulin infusion cannulas are inserted separately. A new device, MiniMed Duo, combines sensing and infusion capabilities on the same platform and is intended to simplify device insertion and site management. We evaluated the device's performance with respect to insulin delivery and glucose sensing, and its acceptability with patients. Forty-five patients (mean ± SD age, 45.5 ± 10.9 years, 48% female) with type 1 diabetes and previous use of SAP participated. Each subject was to wear 5 devices connected to insulin pumps over 15 days (3 days/device) and test capillary blood glucose (SMBG) 7 times/day. The primary endpoint was the percentage of sensor-SMBG paired values within 20% of one another. Subject experiences were assessed via questionnaires. Overall, 74.8% of sensor-SMBG paired values were within 20%, meeting the primary accuracy endpoint, and the mean absolute relative difference was 15.5 ± 17.1%. Consensus error grid analysis showed that >95% of points were within the A+B zones, exceeding the threshold for adequate clinical accuracy. Insulin dosage and SMBG values did not change significantly compared to prestudy values. The functional survival of the device entering day 3 was 90.5%. There were no serious adverse events. Mean questionnaire results indicated overall satisfaction with the device. Duo provided insulin infusion and glucose sensing capabilities in a single device, which provided accurate glucose readings during routine use, was safe to wear, and was acceptable to most patients. It may improve satisfaction and convenience for patients using sensor-augmented insulin pumps.

  5. Intra-day signal instabilities affect decoding performance in an intracortical neural interface system

    NASA Astrophysics Data System (ADS)

    Perge, János A.; Homer, Mark L.; Malik, Wasim Q.; Cash, Sydney; Eskandar, Emad; Friehs, Gerhard; Donoghue, John P.; Hochberg, Leigh R.

    2013-06-01

    Objective. Motor neural interface systems (NIS) aim to convert neural signals into motor prosthetic or assistive device control, allowing people with paralysis to regain movement or control over their immediate environment. Effector or prosthetic control can degrade if the relationship between recorded neural signals and intended motor behavior changes. Therefore, characterizing both biological and technological sources of signal variability is important for a reliable NIS. Approach. To address the frequency and causes of neural signal variability in a spike-based NIS, we analyzed within-day fluctuations in spiking activity and action potential amplitude recorded with silicon microelectrode arrays implanted in the motor cortex of three people with tetraplegia (BrainGate pilot clinical trial, IDE). Main results. 84% of the recorded units showed a statistically significant change in apparent firing rate (3.8 ± 8.71 Hz or 49% of the mean rate) across several-minute epochs of tasks performed on a single session, and 74% of the units showed a significant change in spike amplitude (3.7 ± 6.5 µV or 5.5% of mean spike amplitude). 40% of the recording sessions showed a significant correlation in the occurrence of amplitude changes across electrodes, suggesting array micro-movement. Despite the relatively frequent amplitude changes, only 15% of the observed within-day rate changes originated from recording artifacts such as spike amplitude change or electrical noise, while 85% of the rate changes most likely emerged from physiological mechanisms. Computer simulations confirmed that systematic rate changes of individual neurons could produce a directional ‘bias’ in the decoded neural cursor movements. Instability in apparent neuronal spike rates indeed yielded a directional bias in 56% of all performance assessments in participant cursor control (n = 2 participants, 108 and 20 assessments over two years), resulting in suboptimal performance in these sessions

  6. Factors affecting the performance of microbial fuel cells for sulfur pollutants removal.

    PubMed

    Zhao, Feng; Rahunen, Nelli; Varcoe, John R; Roberts, Alexander J; Avignone-Rossa, Claudio; Thumser, Alfred E; Slade, Robert C T

    2009-03-15

    A microbial fuel cell (MFC) has been developed for removal of sulfur-based pollutants and can be used for simultaneous wastewater treatment and electricity generation. This fuel cell uses an activated carbon cloth+carbon fibre veil composite anode, air-breathing dual cathodes and the sulfate-reducing species Desulfovibrio desulfuricans. 1.16gdm(-3) sulfite and 0.97gdm(-3) thiosulfate were removed from the wastewater at 22 degrees C, representing sulfite and thiosulfate removal conversions of 91% and 86%, respectively. The anode potential was controlled by the concentration of sulfide in the compartment. The performance of the cathode assembly was affected by the concentration of protons in the cation-exchanging ionomer with which the electrocatalyst is co-bound at the three-phase (air, catalyst and support) boundary.

  7. Experimental investigation of air pressure affecting filtration performance of fibrous filter sheet.

    PubMed

    Xu, Bin; Yu, Xiao; Wu, Ya; Lin, Zhongping

    2017-03-01

    Understanding the effect of air pressure on their filtration performance is important for assessing the effectiveness of fibrous filters under different practical circumstances. The effectiveness of three classes of air filter sheets were investigated in laboratory-based measurements at a wide range of air pressures (60-130 KPa). The filtration efficiency was found most sensitive to the air pressure change at smaller particle sizes. As the air pressure increased from 60 to 130 KPa, significant decrease in filtration efficiency (up to 15%) and increase in pressure drop (up to 90 Pa) were observed. The filtration efficiency of the filter sheet with largest fiber diameter and smallest solid volume fraction was affected most, while the pressure drop of the filter sheet with smallest fiber diameter and largest solid volume fraction was affected most. The effect of air pressure on the filtration efficiency was slightly larger at greater filter face air velocity. However, the effect of air pressure on the pressure drop was negligible. The filtration efficiency and pressure drop were explicitly expressed as functions of the air pressure. Two coefficients were empirically derived and successfully accounted for the effects of air pressure on filtration efficiency and pressure drop.

  8. Caterpillar abundance in the territory affects the breeding performance of great tit Parus major minor.

    PubMed

    Seki, Shin-Ichi; Takano, Hajime

    1998-05-01

    The effects of caterpillar food supply on the breeding performance of a population of the Japanese great tit Parus major minor were investigated. Since more than 90% of the food items in our study site were caterpillars living on trees, we estimated the food availability using 20 frass traps per hectare. The sampling error of this method was about 10% on average, which was accurate enough to detect differences between territories. Food abundance at laying in each territory affected the timing of egg laying. However, food amount after hatching was correlated with clutch size. No relationship was found between fledgling quality and food availability, probably because the effects of local variation in food abundance could be canceled out by parental effort such as extending the foraging area. There was a significant negative correlation between the length of the nestling period and food availability. We suggest that parent tits decide the timing of fledging at the point where two factors, predation risk before fledging and additional improvement of nestling quality, are balanced. Food availability just after fledging affected the length of post-fledging parental care; it seems that fledglings in "poor" territories would have had difficulty in finding food and hence needed to depend on their parents longer than those in "rich" territories.

  9. Do centrally programmed anticipatory postural adjustments in fast stepping affect performance of an associated "touche" movement?

    PubMed

    Do, M C; Yiou, E

    1999-12-01

    Ensuring maximum speed in executing a sequence of two voluntary movements requires the second movement to be triggered only after some delay. This is due to the existence of a "relative refractory period." If the second movement is initiated during the refractory period, its speed decreases (movement time increases). In the present study we tested the existence of a refractory period during the execution of a sequence of movements involving both the upper and the lower limbs. More precisely, we examined whether the maximal speed of the touche fencing movement is affected by the anticipatory postural adjustments (APA) preceding a voluntary lunge. The touche and the lunge are similar to a pointing task and a stepping forward movement, respectively. touche consists of hitting a target with a foil at maximal velocity. The results show that (a) when the touche was initiated prior to the onset of the APA of the lunge, the maximal foil velocity remains similar to that of an isolated touche, and (b) when the touche is initiated during the development of the APA of the lunge, the maximal foil velocity is lower than in the isolated touche. Furthermore, the maximal foil velocity decreases with the temporal progression of the APA and reaches its minimal value when initiated at the time of voluntary lunge execution ('foot off'). The discussion suggests that the centrally programmed APA that are elicited in the stepping forward movement induces a refractory period which affects performance of the pointing task.

  10. Grape variety affects larval performance and also female reproductive performance of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae).

    PubMed

    Moreau, J; Benrey, B; Thiéry, D

    2006-04-01

    For insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.

  11. Personality Traits Affect Teaching Performance of Attending Physicians: Results of a Multi-Center Observational Study

    PubMed Central

    Scheepers, Renée A.; Lombarts, Kiki M. J. M. H.; van Aken, Marcel A. G.; Heineman, Maas Jan; Arah, Onyebuchi A.

    2014-01-01

    Background Worldwide, attending physicians train residents to become competent providers of patient care. To assess adequate training, attending physicians are increasingly evaluated on their teaching performance. Research suggests that personality traits affect teaching performance, consistent with studied effects of personality traits on job performance and academic performance in medicine. However, up till date, research in clinical teaching practice did not use quantitative methods and did not account for specialty differences. We empirically studied the relationship of attending physicians' personality traits with their teaching performance across surgical and non-surgical specialties. Method We conducted a survey across surgical and non-surgical specialties in eighteen medical centers in the Netherlands. Residents evaluated attending physicians' overall teaching performance, as well as the specific domains learning climate, professional attitude, communication, evaluation, and feedback, using the validated 21-item System for Evaluation of Teaching Qualities (SETQ). Attending physicians self-evaluated their personality traits on a 5-point scale using the validated 10-item Big Five Inventory (BFI), yielding the Five Factor model: extraversion, conscientiousness, neuroticism, agreeableness and openness. Results Overall, 622 (77%) attending physicians and 549 (68%) residents participated. Extraversion positively related to overall teaching performance (regression coefficient, B: 0.05, 95% CI: 0.01 to 0.10, P = 0.02). Openness was negatively associated with scores on feedback for surgical specialties only (B: −0.10, 95% CI: −0.15 to −0.05, P<0.001) and conscientiousness was positively related to evaluation of residents for non-surgical specialties only (B: 0.13, 95% CI: 0.03 to 0.22, p = 0.01). Conclusions Extraverted attending physicians were consistently evaluated as better supervisors. Surgical attending physicians who display high levels of

  12. Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof.

    PubMed

    Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy

    2016-05-15

    Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%-26% volumetric moisture content) and temperature (21°C-36°C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat

  13. Motion and emotion: depression reduces psychomotor performance and alters affective movements in caregiving interactions

    PubMed Central

    Young, Katherine S.; Parsons, Christine E.; Stein, Alan; Kringelbach, Morten L.

    2015-01-01

    Background: Impaired social functioning is a well-established feature of depression. Evidence to date suggests that disrupted processing of emotional cues may constitute part of this impairment. Beyond processing of emotional cues, fluent social interactions require that people physically move in synchronized, contingent ways. Disruptions to physical movements are a diagnostic feature of depression (psychomotor disturbance) but have not previously been assessed in the context of social functioning. Here we investigated the impact of psychomotor disturbance in depression on physical responsive behavior in both an experimental and observational setting. Methods: In Experiment 1, we examined motor disturbance in depression in response to salient emotional sounds, using a laboratory-based effortful motor task. In Experiment 2, we explored whether psychomotor disturbance was apparent in real-life social interactions. Using mother-infant interactions as a model affective social situation, we compared physical behaviors of mothers with and without postnatal depression (PND). Results: We found impairments in precise, controlled psychomotor performance in adults with depression relative to healthy adults (Experiment 1). Despite this disruption, all adults showed enhanced performance following exposure to highly salient emotional cues (infant cries). Examining real-life interactions, we found differences in physical movements, namely reduced affective touching, in mothers with PND responding to their infants, compared to healthy mothers (Experiment 2). Conclusions: Together, these findings suggest that psychomotor disturbance may be an important feature of depression that can impair social functioning. Future work investigating whether improvements in physical movement in depression could have a positive impact on social interactions would be of much interest. PMID:25741255

  14. OPERATIONAL AND COMPOSITIONAL FACTORS THAT AFFECT THE PERFORMANCE PROPERTIES OF ARP/MCU SALTSTONE GROUT

    SciTech Connect

    Reigel, M.; Edwards, T.; Pickenheim, B.

    2012-02-15

    that of the sample cured at room temperature. The hydration reactions initiated during the mixing of the premix and salt solution continue during the curing period in the vaults to produce the hardened waste form product. The heat generated from exothermic hydration reactions results in a temperature increase in the vaults that depends on the composition of the decontaminated salt solution being dispositioned, the grout formulation (mix design) and the pour frequency and volume. This heat generation is a contributing factor to the temperature increase in the vaults that leads to an increased cure temperature for the grout. This report will further investigate the impact of curing temperature on saltstone performance properties (hydraulic conductivity, Young's modulus, porosity, etc.) over a range of aluminate concentration, water to premix (w/p) ratio and weight percent fly ash in the premix processed at the SPF. The three curing temperatures selected for this study were chosen to provide data at fixed cure temperatures that represent measured temperatures in the SDF vaults. This does not represent the conditions in the vault where the temperature of the saltstone is continually changing with time. For example, it may take several days for the saltstone to reach 60 C at a given elevation. Previous results demonstrated that the rates at which a selected curing temperature is reached affect the performance properties. The approach taken in this task, a rapid increase to the curing temperature, may be conservative with respect to decreased performance. Nevertheless, the data will provide a basis from which to determine the impact of curing temperature on saltstone performance as a function of key variables. A statistical evaluation of the results for these mixes will be performed to provide the range, and associated uncertainties, of hydraulic conductivity and other properties over this factor space.

  15. Factors affecting animal performance during the grazing season in a mountain cattle production system.

    PubMed

    Casasús, I; Sanz, A; Villalba, D; Ferrer, R; Revilla, R

    2002-06-01

    The factors influencing weight changes during the grazing season of Brown Swiss autumn-calving cows and Brown Swiss and Pirenaica spring-calving cows and their calves were studied over an 8-yr period in Spanish mountain conditions. The data set comprised 552 annual production cycles of cows that calved in two consecutive years. The animals grazed on alpine ranges during the summer and on forest pastures in the spring and autumn. They were housed during the winter and fed at different feeding levels (83 to 117% of their energy requirements) throughout the years of study. Weights were recorded every 3 mo and corrected to account for changes of digestive content and fetal growth, using theoretical relationships. Cow weight gains both on forest pastures and high mountain ranges were higher in autumn- than in spring-calving Brown Swiss cows, and therefore also during the whole grazing season (52.1 vs 7.7 kg, respectively, P < 0.001). Therefore, weight at calving and thereafter was significantly higher in autumn- than in spring-calving cows, which was associated with better reproductive performance (35.5 vs 49.1 d from calving to first ovulation, P < 0.01). In the spring-calving herd, Pirenaica cows had slightly higher gains than Brown Swiss cows during the grazing period (18.5 vs 7.7 kg, P < 0.001), mainly due to their higher gains on forest pastures, but their reproductive performance was similar (44.5 vs 49.1 d from calving to first ovulation, respectively, not statistically significant). Gains were higher in multiparous than in primiparous cows (31.1 vs 14.1 kg, respectively, P < 0.001), especially in the case of Brown Swiss cows, which were younger at first calving. Gains were affected by year of study (P < 0.001) and previous weight changes during the housing period (r = -0.35 and r = -0.21 in autumn- and spring-calving cows respectively, P < 0.001). In the case of autumn-calving cows, performance on pasture was also affected by the stage of pregnancy at housing (r

  16. Oral contraceptive cycle phase does not affect 200-m swim time trial performance.

    PubMed

    Rechichi, Claire; Dawson, Brian

    2012-04-01

    The purpose of this study was to examine whether swimming performance was affected by acute hormonal fluctuation within a monophasic oral contraceptive (OC) cycle. Six competitive swimmers and water polo players completed a 200-m time trial at 3 time points of a single OC cycle: during the consumption phase (CONS), early (WITH1), and late in the withdrawal phase (WITH2). Split times and stroke rate were recorded during the time trial, and heart rate, blood lactate, glucose, and pH were measured after each performance test. Resting endogenous serum estradiol and progesterone concentrations were also assessed. No significant differences were observed between phases for body composition, 200-m swim time, mean stroke rate, peak heart rate, or blood glucose (p > 0.05). The mean peak blood lactate was significantly lower during WITH2 (9.9 ± 3.0 mmol·L(-1)) compared with that of CONS (12.5 ± 3.0 mmol·L(-1)) and mean pH higher during WITH2 (7.183 ± 0.111) compared with that of CONS (7.144 ± 0.092). Serum estradiol levels were significantly greater during WITH2 compared with that during WITH1 and CONS, but there was no difference in serum progesterone levels. These results demonstrate that for monophasic OC users, cycle phase does not impact the 200-m swimming performance. There was a reduction in blood lactate and an increase in pH during the withdrawal phase, possibly because of an increase in fluid retention, plasma volume, and cellular alkalosis. Therefore, female 200-m swimmers taking a monophasic OC need not be concerned by the phase of their cycle with regard to competition and optimizing performance. However, coaches and scientists should exercise caution when interpreting blood lactate results obtained from swimming tests and consider controlling for cycle phase for athletes taking an OC.

  17. Influence of a bleaching post-exposure treatment in the performance of H-PDLC devices with high electric conductivity

    NASA Astrophysics Data System (ADS)

    Ortuño, Manuel; Márquez, Andrés.; Gallego, Sergi; Fernandez, Roberto; Navarro-Fuster, Víctor; Beléndez, Augusto; Pascual, Inmaculada

    2014-08-01

    Holographic polymer dispersed liquid crystals (H-PDLC) are made by holographic recording in a photo-polymerization induced phase separation process in which the liquid crystal molecules diffuse to dark zones in the diffraction grating. The devices with H-PDLC materials develop a dynamic behavior that may be modified by means of an electric field. We study a photopolymer formulation with high diffraction efficiency but with the problem of high electric conductivity. We use a bleaching post-exposure treatment to obtain devices with a better electro-optical performance.

  18. Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography.

    PubMed

    Qian, Jueying; Horn, Harald; Tarchitzky, Jorge; Chen, Yona; Katz, Sagi; Wagner, Michael

    2017-03-01

    Drip irrigation is a water-saving technology. To date, little is known about how biofilm forms in drippers of irrigation systems. In this study, the internal dripper geometry was recreated in 3-D printed microfluidic devices (MFDs). To mimic the temperature conditions in (semi-) arid areas, experiments were conducted in a temperature controlled box between 20 and 50°C. MFDs were either fed with two different treated wastewater (TWW) or synthetic wastewater. Biofilm formation was monitored non-invasively and in situ by optical coherence tomography (OCT). 3-D OCT datasets reveal the major fouling position and illustrate that biofilm development was influenced by fluid dynamics. Biofilm volumetric coverage of the labyrinth up to 60% did not reduce the discharge rate, whereas a further increase to 80% reduced the discharge rate by 50%. Moreover, the biofilm formation rate was significantly inhibited in daily temperature cycle independent of the cultivation medium used.

  19. Factors affecting numerical typing performance of young adults in a hear-and-type task.

    PubMed

    Lin, Cheng-Jhe; Wu, Changxu

    2011-12-01

    Numerical hear-and-type tasks, i.e. making immediate keypresses according to verbally presented numbers, possess both practical and theoretical importance but received relatively little attention. Effects of speech rates (500-ms vs. 1000-ms interval), urgency (urgent condition: performance-based monetary incentive plus time limit vs. non-urgent condition: flat-rate compensation) and finger strategies (single vs. multi-finger typing) on typing speed and accuracy were investigated. Fast speech rate and multi-finger typing produced more errors and slower typing speed. Urgency improved typing speed but decreased accuracy. Errors were almost doubled under urgent condition, while urgency effect on speed was similar to that of speech rate. Examination of error patterns did not fully support Salthouse's (1986) speculations about error-making mechanisms. The results implied that urgency could play a more important role in error-making than task demands. Numerical keyboard design and error detection could benefit from spatial incidence of errors found in this study. STATEMENT OF RELEVANCE: This study revealed that classic speculations about error-making mechanisms in alphabetical typing do not necessarily translate to numerical typing. Factors other than external task demands such as urgency can affect typing performance to a similar or greater extent. Investigations of intrinsic error-making factors in non-traditional typing tasks are encouraged.

  20. Computer-Detected Attention Affects Foreign Language Listening but Not Reading Performance.

    PubMed

    Lee, Shu-Ping

    2016-08-01

    No quantitative study has explored the influence of attention on learning English as a foreign language (EFL). This study investigated whether computer-detected attention is associated with EFL reading and listening and reading and listening anxiety. Traditional paper-based English tests used as entrance examinations and tests of general trait anxiety, reading, listening, reading test state anxiety, and listening test state anxiety were administered in 252 Taiwan EFL college students who were divided into High Attention (Conners' Continuous Performance Test, CPT < 50) and Low Attention (CPT ≥ 50) groups. No differences were found between the two groups for traditional paper-based English tests, trait anxieties, general English reading anxiety scales, and general English listening anxiety scales. The Low Attention group had higher test state anxiety and lower listening test scores than the High Attention group, but not in reading. State anxiety during listening tests for EFL students with computer-detected low attention tendency was elevated and their EFL listening performance was affected, but those differences were not found in reading.

  1. Factors affecting the stability and performance of ipratropium bromide; fenoterol hydrobromide pressurized-metered dose inhalers.

    PubMed

    Ninbovorl, Jenjira; Sawatdee, Somchai; Srichana, Teerapol

    2013-12-01

    The aim of the study was to investigate the factors affecting the stability and performance of ipratropium bromide and fenoterol hydrobromide in a pressurized-metered dose inhaler (pMDI). A factorial design was applied to investigate the effects of three parameters (propellant, water, and ethanol) on the performance of 27 designed formulations of a solution-based pMDI. The formulations that contained a hydrofluoroalkane (HFA) propellant lower than 72% v/v and an ethanol concentration higher than 27% v/v remained as clear solutions. Nine formulations that contained the HFA propellant higher than 74% v/v precipitated. The results indicated that it was not only the HFA propellant content of the formulations that was related to the formulation instability but also ethanol content. Only six formulations from the 18 formulations, that did not precipitate, produced drug contents that were within the acceptable range (80-120%). These six formulations generated aerosols with mass median aerodynamic diameters (MMAD) of approximately 2 μm with a fine particle fraction (FPF; particle size, <6.4 μm) between 45% and 52%. The MMAD and FPF did not change significantly after 6 months of storage (P > 0.05).

  2. Affective judgment and beneficial decision making: ventromedial prefrontal activity correlates with performance in the Iowa Gambling Task.

    PubMed

    Northoff, Georg; Grimm, Simone; Boeker, Heinz; Schmidt, Conny; Bermpohl, Felix; Heinzel, Alexander; Hell, Daniel; Boesiger, Peter

    2006-07-01

    Damasio proposes in his somatic marker theory that not only cognitive but also affective components are critical for decision making. Since affective judgment requires an interplay between affective and cognitive components, it might be considered a key process in decision making that has been linked to neural activity in ventromedial prefrontal cortex (VMPFC). Using functional magnetic resonance imaging (fMRI), we examined the relationship between VMPFC, emotionally (unexpected)- and cognitively (expected)-accentuated affective judgment, and beneficial decision making (Iowa Gambling Task; IGT) in healthy subjects. Neuronal activity in the VMPFC during unexpected affective judgment significantly correlated with both global and final performance in the IGT task. These findings suggest that the degree to which subjects recruit the VMPFC during affective judgment is related to beneficial performance in decision making in gambling.

  3. Factors affecting the performance of community health workers in India: a multi-stakeholder perspective

    PubMed Central

    Sharma, Reetu; Webster, Premila; Bhattacharyya, Sanghita

    2014-01-01

    Background Community health workers (CHWs) form a vital link between the community and the health department in several countries. In India, since 2005 this role is largely being played by Accredited Social Health Activists (ASHAs), who are village-level female workers. Though ASHAs primarily work for the health department, in a model being tested in Rajasthan they support two government departments. Focusing on the ASHA in this new role as a link worker between two departments, this paper examines factors associated with her work performance from a multi-stakeholder perspective. Design The study was done in 16 villages from two administrative blocks of Udaipur district in Rajasthan. The findings are based on 63 in-depth interviews with ASHAs, their co-workers and representatives from the two departments. The interviews were conducted using interview guides. An inductive approach with open coding was used for manual data analysis. Results This study shows that an ASHA's motivation and performance are affected by a variety of factors that emerge from the complex context in which she works. These include various personal (e.g. education), professional (e.g. training, job security), and organisational (e.g. infrastructure) factors along with others that emerge from external work environment. The participants suggested various ways to address these challenges. Conclusion In order to improve the performance of ASHAs, apart from taking corrective actions at the professional and organisational front on a priority basis, it is equally essential to promote cordial work relationships amongst ASHAs and other community-level workers from the two departments. This will also have a positive impact on community health. PMID:25319596

  4. Performance of sanitary sewer collection system odour control devices operating in diverse conditions.

    PubMed

    Camarillo, Mary Kay; Stringfellow, William T; Hanlon, Jeremy S; Basha, Elizabeth

    2013-01-01

    Controlling odours from sanitary sewer systems is challenging as a result of the expansive nature of these systems. Addition of oxidizing chemicals is often practiced as a mitigation strategy. One alternative is to remove odorous compounds in the gases vented from manholes using adsorptive media. In this study, odour control devices located at manholes were observed to determine the ability of these systems to reduce hydrogen sulphide from vented gases. The odour control devices incorporated pressure regulation to control gas flow out of manhole covers and adsorptive media to remove hydrogen sulphide in the vented gases prior to release. Pressure regulation was accomplished using a variable volume bladder and two pressure relief valves that permitted gas flow when pressures exceeded 1.3 to 2.5 cm water column. The reduction in gas flow vented from manholes was intended to extend the service life of the adsorptive media, as compared with odour control devices that do not incorporate pressure modulation. Devices were deployed at four locations and three adsorptive media were tested. Although measured collection system hydrogen sulphide concentrations varied from zero to over 1,000 ppm, the removal rates observed using odour control devices were typically above 90%. The lower removal rates observed at one of the sites (50.5 ± 36.1%) appeared related to high gas flow rates being emitted at this location. Activated carbon was used in most of the tests, although use of iron media resulted in the highest removal observed: 97.8 ± 3.6%. The expected service life of the adsorptive media contained within the odour control devices is a function of site-specific hydrogen sulphide concentrations and gas flow rates. The units used in this study were in service for more than 8 to 12 months prior to requiring media replacement.

  5. Investigation of Device Performance and Negative Bias Temperature Instability of Plasma Nitrided Oxide in Nanoscale p-Channel Metal-Oxide-Semiconductor Field-Effect Transistor's

    NASA Astrophysics Data System (ADS)

    Han, In-Shik; Ji, Hee-Hwan; Goo, Tae-Gyu; Yoo, Ook-Sang; Choi, Won-Ho; Na, Min-Ki; Kim, Yong-Goo; Park, Sung-Hyung; Lee, Heui-Seung; Kang, Young-Seok; Kim, Dae-Byung; Lee, Hi-Deok

    2008-04-01

    In this paper, we investigated the device performance and negative bias temperature instability (NBTI) degradation for thermally nitrided oxide (TNO) and plasma nitrided oxide (PNO) in nanoscale p-channel metal oxide semiconductor field effect transistor (PMOSFET). PNOs show the improvement of dielectric performance compared to TNO with no change of the device performance. PNOs also show the improvement of NBTI immunity than TNO at low temperature stress, whereas NBTI immunity of PNO with high N concentration can be worse than TNO at high temperature stress. Recovery effect of NBTI degradation of PNO is lower than that of TNO and it is increased as the N concentration is increased in PNO because the dissociated Si dangling bonds and generated positive oxide charges are repassivated and neutralized, respectively. Moreover, complete recovery of ΔVth is dominated by neutralization of positive oxide charges. Therefore, N contents at polycrystalline Si/SiO2 interface as well as N contents at Si/SiO2 interface can affect significantly on NBTI degradation and recovery effect.

  6. Planar source pocket (PSP) tunnel MOSFET: Potential device solution for low power applications and improving tunneling MOSFET performance

    NASA Astrophysics Data System (ADS)

    Nagavarapu, Venkatagirish

    As MOSFET is scaled below 90nm, many daunting challenges arise. Short channel effects (DIBL and VTH roll-off), off-state leakage, parasitic capacitance and resistance severely limit the performance of these transistors. Moreover as the device dimensions are being scaled down into the nanometer regime, power dissipation is becoming a principal concern. Supply voltage scaling constraints and the diffusion limit of 60mv/dec on the sub-threshold swing (SS) lead to reduced ION/IOFF and high I OFF. This leads to higher active power dissipation and sub-threshold power consumption. To provide for a given overdrive and control power dissipation, lower threshold voltage is required while maintaining a low IOFF. This points to the pressing need for devices with steep (< 60mv/dec) sub-threshold behavior. New device innovations are essential to overcome these challenges. In recent years, research in novel devices (tunneling FETs, IMOS [1], [2]) for possible solutions towards providing steep sub-threshold behavior and improved ION at lower operating voltages has gained a lot of momentum. Most of the tunneling devices investigated have the configuration of gate controlled reverse biased p-i-n diodes ([3] - [8

  7. Reduction of molecular aggregation and its application to the high-performance blue perylene-doped organic electroluminescent device

    NASA Astrophysics Data System (ADS)

    Mi, B. X.; Gao, Z. Q.; Lee, C. S.; Lee, S. T.; Kwong, H. L.; Wong, N. B.

    1999-12-01

    A nonplanar derivative of perylene, 2,5,8,11-tetra-tertbutylperylene (TBPe), was synthesized via the Friedel-Crafts alkylation reaction. Electroluminescent (EL) devices were made using TBPe or perylene as a dopant in bis(2-methyl-8-quinolinolato)(para-phenylphenolato)aluminum(III) and their EL performance was compared. Similar to the device doped with the parent perylene molecule, the device doped with TBPe also emitted strongly in the blue. As the concentration of TBPe increased from 1% to 5%, the color coordinates in CIE 1931 chromaticity of the TBPe-doped device changed only slightly from (0.168,0.273) to (0.175,0.273), whereas the perylene-doped device exhibited a much larger shift from (0.165,0.196) to (0.178,0.252). The constancy of EL color and efficiency with respect to TBPe dopant concentration is attributable to diminishing molecular aggregation in the nonplanar perylene derivative, TBPe, due to the steric hindrance of the tert-butyl groups.

  8. High performance superconducting devices enabled by three dimensionally ordered nanodots and/or nanorods

    DOEpatents

    Goyal, Amit

    2013-09-17

    Novel articles and methods to fabricate same with self-assembled nanodots and/or nanorods of a single or multicomponent material within another single or multicomponent material for use in electrical, electronic, magnetic, electromagnetic and electrooptical devices is disclosed. Self-assembled nanodots and/or nanorods are ordered arrays wherein ordering occurs due to strain minimization during growth of the materials. A simple method to accomplish this when depositing in-situ films is also disclosed. Device applications of resulting materials are in areas of superconductivity, photovoltaics, ferroelectrics, magnetoresistance, high density storage, solid state lighting, non-volatile memory, photoluminescence, thermoelectrics and in quantum dot lasers.

  9. High performance devices enabled by epitaxial, preferentially oriented, nanodots and/or nanorods

    DOEpatents

    Goyal, Amit

    2011-10-11

    Novel articles and methods to fabricate same with self-assembled nanodots and/or nanorods of a single or multicomponent material within another single or multicomponent material for use in electrical, electronic, magnetic, electromagnetic, superconducting and electrooptical devices is disclosed. Self-assembled nanodots and/or nanorods are ordered arrays wherein ordering occurs due to strain minimization during growth of the materials. A simple method to accomplish this when depositing in-situ films is also disclosed. Device applications of resulting materials are in areas of superconductivity, photovoltaics, ferroelectrics, magnetoresistance, high density storage, solid state lighting, non-volatile memory, photoluminescence, thermoelectrics and in quantum dot lasers.

  10. High performance electrical, magnetic, electromagnetic and electrooptical devices enabled by three dimensionally ordered nanodots and nanorods

    DOEpatents

    Goyal, Amit , Kang; Sukill, [Knoxville, TN

    2012-02-21

    Novel articles and methods to fabricate same with self-assembled nanodots and/or nanorods of a single or multicomponent material within another single or multicomponent material for use in electrical, electronic, magnetic, electromagnetic and electrooptical devices is disclosed. Self-assembled nanodots and/or nanorods are ordered arrays wherein ordering occurs due to strain minimization during growth of the materials. A simple method to accomplish this when depositing in-situ films is also disclosed. Device applications of resulting materials are in areas of superconductivity, photovoltaics, ferroelectrics, magnetoresistance, high density storage, solid state lighting, non-volatile memory, photoluminescence, thermoelectrics and in quantum dot lasers.

  11. Performance of able-bodied subjects on a text-typing task using a head-operated device and expanded membrane cursor keys.

    PubMed

    Capilouto, Gilson J; McClenaghan, Bruce; Williams, Harriet G; Dickerson, John; Hussey, James R

    2004-02-01

    Children and adults with disabilities frequently rely on computers to complete written tasks. Those with significant motor limitations typically use alternative computer-input devices since the traditional keyboard and mouse are insufficient to accommodate their abilities. For persons unable to isolate their fingers, input devices controlled by movements of the head or whole hand or arm movements may be among the options considered. This study investigated the performance of a head-operated device and expanded membrane cursor keys for text entry. Data from 24 young adults indicated the head-operated device performed significantly faster given reduced cognitive demands for device operation, increased stimulus-response compatibility, and simplicity of movement. Use of the expanded membrane cursor keys resulted in significantly lower error rates. No significant differences in comfort or ease of use were reported for the two devices. The relative performance of device options for users sharing similar motor challenges provides rehabilitation specialists with important clinical information.

  12. Performance of a Novel Bipolar/Monopolar Radiofrequency Ablation Device on the Beating Heart in an Acute Porcine Model

    PubMed Central

    Saint, Lindsey L.; Lawrance, Christopher P.; Okada, Shoichi; Kazui, Toshinobu; Robertson, Jason O.; Schuessler, Richard B.; Damiano, Ralph J.

    2013-01-01

    SUMMARY Objective Although the advent of ablation technology has simplified and shortened surgery for atrial fibrillation, only bipolar clamps have reliably been able to create transmural lesions on the beating heart. Currently there are no devices capable of reproducibly creating the long linear lesions in the right and left atria needed to perform a Cox-Maze procedure. This study evaluated the performance of a novel suction-assisted radiofrequency device that uses both bipolar and monopolar energy to create lesions from an epicardial approach on the beating heart. Methods Six domestic pigs underwent median sternotomy. A dual bipolar/monopolar radiofrequency ablation device was used to create epicardial linear lesions on the superior and inferior vena cavae, right and left atrial free walls, and right and left atrial appendages. The heart was stained with 2,3,5-triphenyl-tetrazolium chloride and each lesion was cross-sectioned at 5mm intervals. Lesion depth and transmurality were determined. Results Transmurality was documented in 94% of all cross-sections, and 68% of all ablation lines were transmural along their entire length. Tissue thickness was not different between transmural and non-transmural cross-sections (3.1 ± 1.3 and 3.4 ± 2.1, p=0.57, respectively), nor was the anatomic location on the heart (p=0.45 for the distribution). Of the cross-sections located at the end of the ablation line, 11% (8/75) were found to be non-transmural, whereas only 4% (8/195) of cross-sections located within the line of ablation were found to be non-transmural (p=0.04). Logistic regression analysis demonstrated that failure of the device to create transmural lesions was associated with low body temperature (p=0.006), but not with cardiac output (p=0.54). Conclusions This novel device was able to consistently create transmural epicardial lesions on the beating heart, regardless of anatomic location, cardiac output or tissue thickness. The performance of this device was

  13. Exogenous lactate supply affects lactate kinetics of rainbow trout, not swimming performance

    PubMed Central

    Omlin, Teye; Langevin, Karolanne

    2014-01-01

    Intense swimming causes circulatory lactate accumulation in rainbow trout because lactate disposal (Rd) is not stimulated as strongly as lactate appearance (Ra). This mismatch suggests that maximal Rd is limited by tissue capacity to metabolize lactate. This study uses exogenous lactate to investigate what constrains maximal Rd and minimal Ra. Our goals were to determine how exogenous lactate affects: 1) Ra and Rd of lactate under baseline conditions or during graded swimming, and 2) exercise performance (critical swimming speed, Ucrit) and energetics (cost of transport, COT). Results show that exogenous lactate allows swimming trout to boost maximal Rd lactate by 40% and reach impressive rates of 56 μmol·kg−1·min−1. This shows that the metabolic capacity of tissues for lactate disposal is not responsible for setting the highest Rd normally observed after intense swimming. Baseline endogenous Ra (resting in normoxic water) is not significantly reduced by exogenous lactate supply. Therefore, trout have an obligatory need to produce lactate, either as a fuel for oxidative tissues and/or from organs relying on glycolysis. Exogenous lactate does not affect Ucrit or COT, probably because it acts as a substitute for glucose and lipids rather than extra fuel. We conclude that the observed 40% increase in Rd lactate is made possible by accelerating lactate entry into oxidative tissues via monocarboxylate transporters (MCTs). This observation together with the weak expression of MCTs and the phenomenon of white muscle lactate retention show that lactate metabolism of rainbow trout is significantly constrained by transmembrane transport. PMID:25121611

  14. PFOS affects posterior swim bladder chamber inflation and swimming performance of zebrafish larvae.

    PubMed

    Hagenaars, A; Stinckens, E; Vergauwen, L; Bervoets, L; Knapen, D

    2014-12-01

    Perfluorooctane sulphonate (PFOS) is one of the most commonly detected perfluorinated alkylated substances in the aquatic environment due to its persistence and the degradation of less stable compounds to PFOS. PFOS is known to cause developmental effects in fish. The main effect of PFOS in zebrafish larvae is an uninflated swim bladder. As no previous studies have focused on the effect of PFOS on zebrafish swim bladder inflation, the exact mechanisms leading to this effect are currently unknown. The objective of this study was to determine the exposure windows during early zebrafish development that are sensitive to PFOS exposure and result in impaired swim bladder inflation in order to specify the mechanisms by which this effect might be caused. Seven different time windows of exposure (1-48, 1-72, 1-120, 1-144, 48-144, 72-144, 120-144h post fertilization (hpf)) were tested based on the different developmental stages of the swim bladder. These seven time windows were tested for four concentrations corresponding to the EC-values of 1, 10, 80 and 95% impaired swim bladder inflation (EC1=0.70 mg L(-1), EC10=1.14 mg L(-1), EC80=3.07 mg L(-1) and EC95=4.28 mg L(-1)). At 6 days post fertilization, effects on survival, hatching, swim bladder inflation and size, larval length and swimming performance were assessed. For 0.70 mg L(-1), no significant effects were found for the tested parameters while 1.14 mg L(-1) resulted in a reduction of larval length. For 3.07 and 4.28 mg L(-1), the number of larvae affected and the severity of effects caused by PFOS were dependent on the time window of exposure. Exposure for 3 days or more resulted in significant reductions of swim bladder size, larval length and swimming speed with increasing severity of effects when the duration of exposure was longer, suggesting a possible effect of accumulated dose. Larvae that were only exposed early (1-48 hpf) or late (120-144 hpf) during development showed no effects on the studied endpoints

  15. Emergency CT brain: preliminary interpretation with a tablet device: image quality and diagnostic performance of the Apple iPad.

    PubMed

    Mc Laughlin, Patrick; Neill, Siobhan O; Fanning, Noel; Mc Garrigle, Anne Marie; Connor, Owen J O; Wyse, Gerry; Maher, Michael M

    2012-04-01

    Tablet devices have recently been used in radiological image interpretation because they have a display resolution comparable to desktop LCD monitors. We identified a need to examine tablet display performance prior to their use in preliminary interpretation of radiological images. We compared the spatial and contrast resolution of a commercially available tablet display with a diagnostic grade 2 megapixel monochrome LCD using a contrast detail phantom. We also recorded reporting discrepancies, using the ACR RADPEER system, between preliminary interpretation of 100 emergency CT brain examinations on the tablet display and formal review on a diagnostic LCD. The iPad display performed inferiorly to the diagnostic monochrome display without the ability to zoom. When the software zoom function was enabled on the tablet device, comparable contrast detail phantom scores of 163 vs 165 points were achieved. No reporting discrepancies were encountered during the interpretation of 43 normal examinations and five cases of acute intracranial hemorrhage. There were seven RADPEER2 (understandable) misses when using the iPad display and 12 with the diagnostic LCD. Use of software zoom in the tablet device improved its contrast detail phantom score. The tablet allowed satisfactory identification of acute CT brain findings, but additional research will be required to examine the cause of "understandable" reporting discrepancies that occur when using tablet devices.

  16. Rational material, interface, and device engineering for high-performance polymer and perovskite solar cells (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Jen, Alex K.

    2015-10-01

    The performance of polymer and hybrid solar cells is also strongly dependent on their efficiency in harvesting light, exciton dissociation, charge transport, and charge collection at the metal/organic/metal oxide or the metal/perovskite/metal oxide interfaces. Our laboratory employs a molecular engineering approach to develop processible low band-gap polymers with high charge carrier mobility that can enhance power conversion efficiency of the single junction solar cells to values as high as ~11%. We have also developed several innovative strategies to modify the interface of bulk-heterojunction devices and create new device architectures to fully explore their potential for solar applications. In this talk, the integrated approach of combining material design, interface, and device engineering to significantly improve the performance of polymer and hybrid perovskite photovoltaic cells will be discussed. Specific emphasis will be placed on the development of low band-gap polymers with reduced reorganizational energy and proper energy levels, formation of optimized morphology of active layer, and minimized interfacial energy barriers using functional conductive surfactants. At the end, several new device architectures and optical engineering strategies to make tandem cells and semitransparent solar cells will be discussed to explore the full promise of polymer and perovskite hybrid solar cells.

  17. Effect of the application of an electric field on the performance of a two-phase loop device: preliminary results

    NASA Astrophysics Data System (ADS)

    Creatini, F.; Di Marco, P.; Filippeschi, S.; Fioriti, D.; Mameli, M.

    2015-11-01

    In the last decade, the continuous development of electronics has pointed out the need for a change in mind with regard to thermal management. In the present scenario, Pulsating Heat Pipes (PHPs) are novel promising two-phase passive heat transport devices that seem to meet all present and future thermal requirements. Nevertheless, PHPs governing phenomena are quite unique and not completely understood. In particular, single closed loop PHPs manifest several drawbacks, mostly related to the reduction of device thermal performance and reliability, i.e. the occurrence of multiple operational quasi-steady states. The present research work proposes the application of an electric field as a technique to promote the circulation of the working fluid in a preferential direction and stabilize the device operation. The tested single closed loop PHP is made of a copper tube with an inner tube diameter equal to 2.00 mm and filled with pure ethanol (60% filling ratio). The electric field is generated by a couple of wire-shaped electrodes powered with DC voltage up to 20 kV and laid parallel to the longitudinal axis of the glass tube constituting the adiabatic section. Although the electric field intensity in the working fluid region is weakened both by the polarization phenomenon of the working fluid and by the interposition of the glass tube, the experimental results highlight the influence of the electric field on the device thermal performance and encourage the continuation of the research in this direction.

  18. The effects of electrode cleaning and conditioning on the performance of high-energy, pulsed-power devices

    SciTech Connect

    Cuneo, M.E.

    1998-09-01

    High-energy pulsed-power devices routinely access field strengths above those at which broad-area, cathode-initiated, high-voltage vacuum-breakdown occur (> 1e7--3e7 V/m). Examples include magnetically-insulated-transmission-lines and current convolutes, high-current-density electron and ion diodes, high-power microwave devices, and cavities and other structures for electrostatic and RF accelerators. Energy deposited in anode surfaces may exceed anode plasma thermal-desorption creation thresholds on the time-scale of the pulse. Stimulated desorption by electron or photon bombardment can also lead to plasma formation on electrode or insulator surfaces. Device performance is limited above these thresholds, particularly in pulse length and energy, by the formation and expansion of plasmas formed primarily from electrode contaminants. In-situ conditioning techniques to modify and eliminate the contaminants through multiple high-voltage pulses, low base pressures, RF discharge cleaning, heating, surface coatings, and ion- and electron-beam surface treatment allow access to new regimes of performance through control of plasma formation and modification of the plasma properties. Experimental and theoretical progress from a variety of devices and small scale experiments with a variety of treatment methods will be reviewed and recommendations given for future work.

  19. Affective Factors in the Mediation of Background Effects on Cognitive Performance.

    ERIC Educational Resources Information Center

    Cuttance, Peter F.

    1980-01-01

    Academic achievement at age 16 was influenced more by achievement at age 14 than by affective variables. Affective variables included academic and occupational aspiration, parent expectations, school attitudes, sex, socioeconomic status, parents' education, and migrancy. (CP)

  20. A Device for Performing Lateral Conductance Measurements on Individual Double-Stranded DNA Molecules

    PubMed Central

    Menard, Laurent D.; Mair, Chad E.; Woodson, Michael E.; Alarie, Jean Pierre; Ramsey, J. Michael

    2012-01-01

    A nanofluidic device is described that is capable of electrically monitoring the driven translocation of DNA molecules through a nanochannel. This is achieved by intersecting a long transport channel with a shorter orthogonal nanochannel. The ionic conductance of this transverse nanochannel is monitored while DNA is electrokinetically driven through the transport channel. When DNA passes the intersection, the transverse conductance is altered, resulting in a transient current response. In 1 M KCl solutions, this was found to be a current enhancement of 5–25%, relative to the baseline transverse ionic current. Two different device geometries were investigated. In one device, the DNA was detected after it was fully inserted into and translocating through the transport nanochannel. In the other device, the DNA was detected while it was in the process of entering the nanochannel. It was found that these two conditions are characterized by different transport dynamics. Simultaneous optical and electrical monitoring of DNA translocation confirmed that the transient events originated from DNA transport through the nanochannel intersection. PMID:22950784

  1. The Effect of Asterisks as an Attention Focusing Device on Test Performance of Undergraduate Students.

    ERIC Educational Resources Information Center

    Perrin, David W.; Kerasotes, Dean L.

    It was hypothesized that using asterisks as attention focusing devices would cause students to read all asteriked test items more carefully and would improve test scores of undergraduate education students. Sixty-three undergraduates majoring in elementary or special education were administered a 36-item objective test. Asterisks were used to…

  2. Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping

    PubMed Central

    Saran, Rinku; Stolojan, Vlad; Curry, Richard J.

    2014-01-01

    One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80 dB, a rise time 60 µs and the ability to measure ac signals up to ~250 kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies. PMID:24853479

  3. 40 CFR 65.158 - Performance test procedures for control devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... applicable. The regulated material concentration and percent reduction may be measured as either total... sites. (i) For determination of compliance with a percent reduction requirement of total regulated... site shall be located after the final product recovery device. (B) If a vent stream is introduced...

  4. The synthesis of multi-structured SnS nanocrystals toward enhanced performance for photovoltaic devices.

    PubMed

    Guo, Xin; Xie, Hao-Jun; Zheng, Jia-Wei; Xu, Hao; Wang, Qian-Kun; Li, Yan-Qing; Lee, Shuit-Tong; Tang, Jian-Xin

    2015-01-21

    The synthesis of multi-scale SnS nanostructures with favorable fluorescence is facilely accomplished via a well-excogitated gentle process, involving simple precursors, stabilized chemical medium and primitive ligand exchange. The fabricated SnS nanocrystals can be adopted as hole transporting materials in photovoltaic devices for enhancing its power conversion efficiency.

  5. The performance characteristics of lateral flow devices with 2 strains of highly pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lateral flow devices (LFD) are commercially available and provide a fast, highly specific, on-site test for avian influenza. Because of the low analytic sensitivity of LFD tests at low virus concentrations, targeted sampling of sick and dead birds has been proposed in order to increase detection pr...

  6. 78 FR 18988 - Establishing the Performance Characteristics of In Vitro Diagnostic Devices for the Detection of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ... diagnosis of Lyme disease. DATES: Submit either electronic or written comments on this guidance at any time... of antibodies to B. burgdorferi in human serum, plasma, and blood. These devices are used to aid in the diagnosis of Lyme disease. This document does not apply to B. burgdorferi nucleic...

  7. Pre-Exercise Hyperpnea Attenuates Exercise-Induced Bronchoconstriction Without Affecting Performance

    PubMed Central

    Eichenberger, Philipp A.; Scherer, Thomas A.; Spengler, Christina M.

    2016-01-01

    Whole-body warm-up exercises were shown to attenuate exercise-induced bronchoconstriction (EIB). Whether intense pre-exercise hyperpnea offers similar protection and whether this might negatively affect exercise performance is unknown. Nine subjects with EIB (25±5 yrs; forced expiratory volume in 1s [FEV1], 104±15% predicted) performed an exercise challenge (ECh) followed—after 30min—by a constant-load cycling test to exhaustion. The ECh was preceded by one of four conditions: by i) control warm-up (CON) or by 10min of normocapnic hyperpnea with partial rebreathing at either ii) 50% (WU50) or iii) variable intensity (8x 30s-80%/45s-30%; WU80/30), or at iv) 70% (WU70) of maximal voluntary ventilation. FEV1 was measured at baseline and in 5-min intervals until 15min after CON/warm-up and 30min after ECh. None of the warm-up conditions induced EIB. The maximal post-ECh decrease in FEV1 was -13.8±3.1% after CON, −9.3±5.0% after WU50 (p = 0.081 vs. CON), −8.6±7.5% after WU80/30 (p = 0.081 vs. CON) and −7.2±5.0% after WU70 (p = 0.006 vs. CON), and perception of respiratory exertion was significantly attenuated (all p≤0.048), with no difference between warm-up conditions. Only after CON, FEV1 remained significantly reduced up to the start of the cycling endurance test (−8.0±4.3%, p = 0.004). Cycling performance did not differ significantly between test days (CON: 13±7min; WU50: 14±9min; WU80/30: 13±9min; WU70: 14±7min; p = 0.582). These data indicate that intense hyperpnea warm-up is effective in attenuating EIB severity and accelerating lung function recovery while none of the warm-up condition do compromise cycling performance. PMID:27898744

  8. Laying performance and egg quality of blue-shelled layers as affected by different housing systems.

    PubMed

    Wang, X L; Zheng, J X; Ning, Z H; Qu, L J; Xu, G Y; Yang, N

    2009-07-01

    Blue-shelled eggs are gaining popularity as the consumption demand diversifies in some countries. This study was carried out to investigate the laying performance and egg quality of the blue-shelled egg layers as well as the effects of different housing systems on egg production and quality traits. One thousand pullets from Dongxiang blue-shelled layers were divided into 2 even groups and kept in different housing systems (outdoor vs. cage). Daily laying performance was recorded from 20 to 60 wk of age. External and internal egg quality traits were examined at 26, 34, 42, and 50 wk. Yolk cholesterol concentration and whole egg cholesterol content were measured at 40 wk of age. Average laying rate from 20 to 60 wk for the cage (54.7%) was significantly higher than that of outdoor layers (39.3%). Among all of the egg quality traits, only eggshell color was affected by housing system. Interaction between housing system and layer age was found in egg weight, eggshell color, eggshell ratio, yolk color, and yolk weight. Meanwhile, cholesterol concentration in yolk was 8.64 +/- 0.40 mg/g in the outdoor eggs, which was significantly lower than that of eggs from the cage birds (10.32 +/- 0.48 mg/g; P < 0.05). Whole egg cholesterol content in the outdoor eggs (125.23 +/- 6.32 mg/egg) was also significantly lower than that of eggs from the caged layers (158.01 +/- 8.62 mg/egg). The results demonstrated that blue-shelled layers have lower productivity in the outdoor system than in the cage system. Blue-shelled layers have lower egg weight, larger yolk proportion, and lower cholesterol content compared with commercial layers. In a proper marketing system, lower productivity could be balanced by a higher price for the better quality of blue-shelled eggs.

  9. Sequence analysis reveals genomic factors affecting EST-SSR primer performance and polymorphism.

    PubMed

    Chen, Chunxian; Bock, Clive H; Beckman, Tom G

    2014-12-01

    This study was to explore genomic factors affecting the performance and polymorphism of 340 randomly selected EST-SSR (expressed sequence tag-simple sequence repeat) primers through BLAST of primer sequences to a reference genome. Genotyping showed 111 failed and 229 succeeded. The failed types included "no peaks" (NP, 69 primers), "weak peaks" (WP, 30), and "multiple peaks" (MP, 12). The successful types were divided into HM (homozygous between two selected parents, 78 primers) and HT (heterozygous at least in one parent, 151 primers). The BLAST revealed primer alignment status, genomic amplicon size (GAS), and genomic and expressed amplicon size difference (ASD). The alignment status was categorized as: "no hits found" (NHF); "multiple partial alignments" (MPA); "single partial alignment" (SPA); "multiple full alignments" (MFA); and "single full alignment" (SFA). NHF and partial alignment (PA) mainly resulted from discrepant nucleotides in contig-derived primers. The ASD separated 247 non-NHF primers into: "deletion", "same size", "insertion", "intron (GAS ≤500)", "intron (GAS >500)", and "error" categories. Most SFA primers were successful. About 88 % "error", 53 % NHF primers, and 47 % "intron (GAS >500)" failed. The "deletion" and "insertion" primers had the higher HT rates, and the "same size" had the highest HM rate. Optimized primer selection criteria are discussed.

  10. Cardiovascular and affective consequences of ruminating on a performance stressor depend on mode of thought.

    PubMed

    Zoccola, Peggy M; Rabideau, Erin M; Figueroa, Wilson S; Woody, Alex

    2014-08-01

    Psychological detachment from work is important for facilitating recovery. This can be threatened by rumination, or thinking about the day's stressors. Rumination may lead to distress, fatigue and extended activation of stress-related systems, but findings are not unequivocal. Level of construal (abstract or concrete) and type of mentation (imagery or verbal thought) used during stressor-focused rumination may shape physiological and affective responses and impact recovery. This study tested whether blood pressure (BP) and anxiety responses to stressor-focused rumination differ by mentation type and construal level. Healthy undergraduates (n = 136) performed a speech stressor and then completed a rumination task in one of four randomly assigned conditions: concrete imagery, abstract imagery, concrete verbal thought or abstract verbal thought. Anxiety and continuous BP were assessed. Concrete rumination led to greater BP, whereas rumination with abstract construals led to lower BP. Furthermore, participants in the abstract conditions had greater increases in anxiety following stressor-focused rumination than in the concrete conditions. Results suggest that the immediate physiological and psychological consequences of stressor-focused rumination depend upon mode of thought.

  11. Harnessing Structure-Property Relationships for Poly(alkyl thiophene)-Fullerene Derivative Thin Filmsto Optimize Performance in Photovoltaic Devices

    DOE PAGES

    Deb, Nabankur; Li, Bohao; Skoda, Maximilian; ...

    2016-02-08

    Nanoscale bulk heterojunction (BHJ) systems, consisting of fullerenes dispersed in conjugated polymers as the active component, have been actively studied over the last decades in order to produce high performance organic photovoltaics (OPVs). A significant role in device efficiency is played by the active layer morphology, but despite considerable study, a full understanding of the exact role that morphology plays and therefore a definitive method to produce and control an ideal morphology is lacking. In order to understand the BHJ phase behavior and associated morphology in these devices, we have used neutron reflection, together with grazing incidence X-ray and neutronmore » scattering and X-ray photoelectron spectroscopy (XPS) to determine the morphology of the BHJ active layer in functional devices. We have studied nine model BHJ systems based on mixtures of three poly(3-alkyl thiophenes, P3AT) (A=butyl, hexyl, octyl) blended with three different fullerene derivatives, which provides variations in crystallinity and miscibility within the BHJ composite. In studying properties of functional devices, we show a direct correlation between the observed morphology within the BHJ layer and the device performance metrics, i.e., the short-circuit current (JSC), fill factor (FF), open-circuit voltage (VOC) and overall power conversion efficiency (PCE). Using these model systems, the effect of typical thermal annealing processes on the BHJ morphology through the film thickness as a function of the polythiophene-fullerene mixtures and different electron transport layer interfaces has been determined. It is shown that fullerene enrichment occurs at both the electrode interfaces after annealing. The degree of fullerene enrichment is found to strongly correlate with JSC and to a lesser degree with FF. Finally, based on these findings we demonstrate that by deliberately adding a fullerene layer at the electron transport layer interface, JSC can be increased by up to 20

  12. Harnessing Structure-Property Relationships for Poly(alkyl thiophene)-Fullerene Derivative Thin Filmsto Optimize Performance in Photovoltaic Devices

    SciTech Connect

    Deb, Nabankur; Li, Bohao; Skoda, Maximilian; Rogers, Sarah; Sun, Yan; Gong, Xiong; Karim, Alamgir; Sumpter, Bobby G.; Bucknall, David G.

    2016-02-08

    Nanoscale bulk heterojunction (BHJ) systems, consisting of fullerenes dispersed in conjugated polymers as the active component, have been actively studied over the last decades in order to produce high performance organic photovoltaics (OPVs). A significant role in device efficiency is played by the active layer morphology, but despite considerable study, a full understanding of the exact role that morphology plays and therefore a definitive method to produce and control an ideal morphology is lacking. In order to understand the BHJ phase behavior and associated morphology in these devices, we have used neutron reflection, together with grazing incidence X-ray and neutron scattering and X-ray photoelectron spectroscopy (XPS) to determine the morphology of the BHJ active layer in functional devices. We have studied nine model BHJ systems based on mixtures of three poly(3-alkyl thiophenes, P3AT) (A=butyl, hexyl, octyl) blended with three different fullerene derivatives, which provides variations in crystallinity and miscibility within the BHJ composite. In studying properties of functional devices, we show a direct correlation between the observed morphology within the BHJ layer and the device performance metrics, i.e., the short-circuit current (JSC), fill factor (FF), open-circuit voltage (VOC) and overall power conversion efficiency (PCE). Using these model systems, the effect of typical thermal annealing processes on the BHJ morphology through the film thickness as a function of the polythiophene-fullerene mixtures and different electron transport layer interfaces has been determined. It is shown that fullerene enrichment occurs at both the electrode interfaces after annealing. The degree of fullerene enrichment is found to strongly correlate with JSC and to a lesser degree with FF. Finally, based on these findings we demonstrate that by deliberately adding a fullerene layer at the electron transport layer interface, JSC can be

  13. Force Outputs during Squats Performed Using a Rotational Inertia Device under Stable versus Unstable Conditions with Different Loads

    PubMed Central

    Vázquez-Guerrero, Jairo; Moras, Gerard

    2016-01-01

    The purpose of the study was to compare the force outputs achieved during a squat exercise using a rotational inertia device in stable versus unstable conditions with different loads and in concentric and eccentric phases. Thirteen male athletes (mean ± SD: age 23.7 ± 3.0 years, height 1.80 ± 0.08 m, body mass 77.4 ± 7.9 kg) were assessed while squatting, performing one set of three repetitions with four different loads under stable and unstable conditions at maximum concentric effort. Overall, there were no significant differences between the stable and unstable conditions at each of the loads for any of the dependent variables. Mean force showed significant differences between some of the loads in stable and unstable conditions (P < 0.010) and peak force output differed between all loads for each condition (P < 0.045). Mean force outputs were greater in the concentric than in the eccentric phase under both conditions and with all loads (P < 0.001). There were no significant differences in peak force between concentric and eccentric phases at any load in either stable or unstable conditions. In conclusion, squatting with a rotational inertia device allowed the generation of similar force outputs under stable and unstable conditions at each of the four loads. The study also provides empirical evidence of the different force outputs achieved by adjusting load conditions on the rotational inertia device when performing squats, especially in the case of peak force. Concentric force outputs were significantly higher than eccentric outputs, except for peak force under both conditions. These findings support the use of the rotational inertia device to train the squatting exercise under unstable conditions for strength and conditioning trainers. The device could also be included in injury prevention programs for muscle lesions and ankle and knee joint injuries. PMID:27111766

  14. The performance of smooth-wall drag reducing outer-layer devices in rough-wall boundary layers

    NASA Technical Reports Server (NTRS)

    Bandyopadhyay, P. R.

    1985-01-01

    The boundary layer drag on a 0.28 m x 0.91 m flat-plate was measured to evaluate the performance of smooth-wall drag reducing outer-layer devices in rough-wall boundary layers up to a chord Reynolds number, Re(c) of 17,000. The devices were a pair of thin flat ribbons placed in tandem. The wall conditions examined were smooth, transverse-groove roughnesses having cavity width/depth ratios of 0.7 (d-type) and 3 (k-type), and sandpaper roughness (k-type) of grit sizes 180, 50 and 36. The area-averaged wall-drag was reduced compared to the respective normal levels for all wall conditions. All k-type rough walls exhibited a comparable level of drag reduction (about 7 percent) which was lower than that in the smooth-wall. The d-type rough-wall exhibited a transitional behavior in that the drag reduction dropped from the smooth-wall level to that of the k-type roughnesses with increase in the flow speed. In further experiments on a 6 meter long sandpaper roughened wall and with a pair of symmetric airfoil devices in tandem at an Re(c) of 77,500, it was possible to recover the device drag penalty fully, but no net drag reduction was achieved. The apparent loss of performance of the devices in a rough-wall is explained in terms of their inability to alter the pressure component of the drag in a significant way.

  15. Effect of cuprous halide interlayers on the device performance of ZnPc/C{sub 60} organic solar cells

    SciTech Connect

    Lee, Jinho; Park, Dasom; Heo, Ilsu; Yim, Sanggyu

    2014-10-15

    Highlights: • Effect of CuX interlayers on subsequently deposited films and devices was studied. • CuI is the most effective for the performance of ZnPc/C{sub 60}-based solar cells. • Results were related to the molecular geometry of ZnPc and HOMO level of interlayers. - Abstract: The effect of various cuprous halide (CuX) interlayers introduced between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer and zinc phthalocyanine (ZnPc) layer on the physical properties of the ZnPc thin films and device performances of ZnPc/C{sub 60}-based small-molecule organic solar cells was studied. Strong substrate–molecule interaction between the CuX and ZnPc partly converted surface-perpendicular stacking geometry of ZnPc molecules into surface-parallel one. This flat-lying geometry led to an enhancement in electronic absorption and charge transport within the ZnPc films. As a result, the overall power conversion efficiency of the cell with CuI interlayer increased by ∼37%. In the case of the cells with CuBr and CuCl interlayer, however, the enhancement in device performances was limited because of the reduced conversion of the molecular geometry and increased energy barrier for hole extraction due to the low highest occupied molecular orbital level of the interlayer.

  16. Performance of charge-injection-device infrared detector arrays at low and moderate backgrounds

    NASA Technical Reports Server (NTRS)

    Mckelvey, M. E.; Mccreight, C. R.; Goebel, J. H.; Reeves, A. A.

    1985-01-01

    Three 2 x 64 element charge injection device infrared detector arrays were tested at low and moderate background to evaluate their usefulness for space based astronomical observations. Testing was conducted both in the laboratory and in ground based telescope observations. The devices showed an average readout noise level below 200 equivalent electrons, a peak responsivity of 4 A/W, and a noise equivalent power of 3x10 sq root of W/Hz. Array well capacity was measured to be significantly smaller than predicted. The measured sensitivity, which compares well with that of nonintegrating discrete extrinsic silicon photoconductors, shows these arrays to be useful for certain astronomical observations. However, the measured readout efficiency and frequency response represent serious limitations in low background applications.

  17. Stoichiometric control of lead chalcogenide nanocrystal solids to enhance their electronic and optoelectronic device performance.

    PubMed

    Oh, Soong Ju; Berry, Nathaniel E; Choi, Ji-Hyuk; Gaulding, E Ashley; Paik, Taejong; Hong, Sung-Hoon; Murray, Christopher B; Kagan, Cherie R

    2013-03-26

    We investigate the effects of stoichiometric imbalance on the electronic properties of lead chalcogenide nanocrystal films by introducing excess lead (Pb) or selenium (Se) through thermal evaporation. Hall-effect and capacitance-voltage measurements show that the carrier type, concentration, and Fermi level in nanocrystal solids may be precisely controlled through their stoichiometry. By manipulating only the stoichiometry of the nanocrystal solids, we engineer the characteristics of electronic and optoelectronic devices. Lead chalcogenide nanocrystal field-effect transistors (FETs) are fabricated at room temperature to form ambipolar, unipolar n-type, and unipolar p-type semiconducting channels as-prepared and with excess Pb and Se, respectively. Introducing excess Pb forms nanocrystal FETs with electron mobilities of 10 cm(2)/(V s), which is an order of magnitude higher than previously reported in lead chalcogenide nanocrystal devices. Adding excess Se to semiconductor nanocrystal solids in PbSe Schottky solar cells enhances the power conversion efficiency.

  18. Performance analysis of device-level SINS/ACFSS deeply integrated navigation method

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Qin, Shiqiao; Wang, Xingshu; Jiang, Guangwen; Tan, Wenfeng

    2016-10-01

    The Strap-Down Inertial Navigation System (SINS) is a widely used navigation system. The combination of SINS and the Celestial Navigation System (CNS) is one of the popular measures to constitute the integrated navigation system. A Star Sensor (SS) is used as a precise attitude determination device in CNS. To solve the problem that the star image obtained by SS under dynamic conditions is motion-blurred, the Attitude Correlated Frames (ACF) is presented and the star sensor which works based on ACF approach is named ACFSS. Depending on the ACF approach, a novel device-level SINS/ACFSS deeply integrated navigation method is proposed in this paper. Feedback to the ACF process from the error of the gyro is one of the typical characters of the SINS/CNS deeply integrated navigation method. Herein, simulation results have verified its validity and efficiency in improving the accuracy of gyro and it can be proved that this method is feasible in theory.

  19. Operation Performance of Self-Oscillation Ultrasonic Vibrating Device for Liquid Atomization

    NASA Astrophysics Data System (ADS)

    Toda, Kohji; Ishii, Jun

    1995-09-01

    An ultrasonic vibrating device, composed of a rectangular piezoelectric ceramic plate and a metal plate is described for liquid atomization. The resonance is used for the self-oscillation, which arises from the coupling between two vibration modes in the ceramic plate. The best operation occurs when one of the resonant frequencies of the vibrating device is equal to that of the piezoelectric ceramic plate without the metal plate. The ceramic plate has two electrodes on one of the two surfaces. A power feeding circuit is composed of the piezoelectric ceramic plate with three electrode terminals, which functions as a resonant element as well as a vibration source, and a power amplification transistor. The metal plate with minute holes functions effectively for liquid atomization.

  20. Trends in porous silicon biomedical devices: tuning microstructure and performance trade-offs in optical biosensors

    NASA Astrophysics Data System (ADS)

    DeLouise, Lisa A.; Miller, Ben L.

    2004-07-01

    High surface area mesoporous silicon microcavities are investigated for direct detect optical biosensor applications. Device quality is reported as a function of fabrication parameters. A dilute KOH etch process is utilized to modify the intrinsic 3D microstructure to enable enhanced pore infiltration of large biomolecules. Results suggest that the KOH etch mechanism is a two step process consisting of a fast step where high surface area nanostructures are rapidly removed. This is followed by a slower step where silicon is removed from the pore channel walls. The enzyme, Glutathione-S-Transferase (50kDa), is utilized to probe pore infiltration. Results from a solid phase immobilized enzyme assay support our conclusions on the impact the KOH etch step has on modifying the porous silicon microstructure. Preliminary findings point to trade-offs that exists between optimizing microstructure with microcavity operation mode and device sensitivity.