Correlation of water vapor adsorption behavior of wood with surface thermodynamic properties

Treesearch

Mandla A. Tshabalala; Agnes R. Denes; R. Sam Williams

1999-01-01

To improve the overall performance of wood-plastic composites, appropriate technologies are needed to control moisture sorption and to improve the interaction of wood fiber with selected hydrophobic matrices. The objective of this study was to determine the surface thermodynamic characteristics of a wood fiber and to correlate those characteristics with the fiberas...

Using Screen Capture Feedback to Improve Academic Performance

ERIC Educational Resources Information Center

Denton, David W.

2014-01-01

Feedback is an effective instructional practice for improving achievement. The importance of feedback has been understood by teachers for many years, yet recent research has elevated its status. One characteristic of effective feedback is personalized comments, which assist students in understanding their performance. Most research analyzes the…

Improvement in interfacial characteristics of low-voltage carbon nanotube thin-film transistors with solution-processed boron nitride thin films

NASA Astrophysics Data System (ADS)

Jeon, Jun-Young; Ha, Tae-Jun

2017-08-01

In this article, we demonstrate the potential of solution-processed boron nitride (BN) thin films for high performance single-walled carbon nanotube thin-film transistors (SWCNT-TFTs) with low-voltage operation. The use of BN thin films between solution-processed high-k dielectric layers improved the interfacial characteristics of metal-insulator-metal devices, thereby reducing the current density by three orders of magnitude. We also investigated the origin of improved device performance in SWCNT-TFTs by employing solution-processed BN thin films as an encapsulation layer. The BN encapsulation layer improves the electrical characteristics of SWCNT-TFTs, which includes the device key metrics of linear field-effect mobility, sub-threshold swing, and threshold voltage as well as the long-term stability against the aging effect in air. Such improvements can be achieved by reduced interaction of interfacial localized states with charge carriers. We believe that this work can open up a promising route to demonstrate the potential of solution-processed BN thin films on nanoelectronics.

Diagnostic Utility of the Social Skills Improvement System Performance Screening Guide

ERIC Educational Resources Information Center

Krach, S. Kathleen; McCreery, Michael P.; Wang, Ye; Mohammadiamin, Houra; Cirks, Christen K.

2017-01-01

Researchers investigated the diagnostic utility of the Social Skills Improvement System: Performance Screening Guide (SSIS-PSG). Correlational, regression, receiver operating characteristic (ROC), and conditional probability analyses were run to compare ratings on the SSIS-PSG subscales of Prosocial Behavior, Reading Skills, and Math Skills, to…

Discharge characteristics of 300 ampere-hour Ni-Zn traction cells

NASA Technical Reports Server (NTRS)

Ewashinka, J. G.

1979-01-01

Preliminary tests were performed on 300 amphere-hour nickel-zinc cells containing the Lewis improved inorganic-organic (I/O) separator. These cells also have other design features included to optimize performance and cycle life. The tests carried out were formation tests and characteristic discharge tests. Information obtained include case temperature and maximum power delivered.

Improved LabPET Detectors Using Lu1.8Gd0.2SiO5:Ce (LGSO) Scintillator Blocks

NASA Astrophysics Data System (ADS)

Bergeron, Mélanie; Pepin, Catherine M.; Cadorette, Jules; Loignon-Houle, Francis; Fontaine, Réjean; Lecomte, Roger

2015-02-01

The scintillator is one of the key building blocks that critically determine the physical performance of PET detectors. The quest for scintillation crystals with improved characteristics has been crucial in designing scanners with superior imaging performance. Recently, it was shown that the decay time constant of high lutetium content Lu1.8Gd0.2SiO5: Ce (LGSO) scintillators can be adjusted by varying the cerium concentration from 0.025 mol% to 0.75 mol%, thus providing interesting characteristics for phoswich detectors. The high light output (90%-120% NaI) and the improved spectral match of these scintillators with avalanche photodiode (APD) readout promise superior energy and timing resolutions. Moreover, their improved mechanical properties, as compared to conventional LGSO ( Lu0.4Gd1.6SiO5: Ce), make block array manufacturing readily feasible. To verify these assumptions, new phoswich block arrays made of LGSO-90%Lu with low and high mol% Ce concentrations were fabricated and assembled into modules dedicated to the LabPET scanner. Typical crystal decay time constants were 31 ns and 47 ns, respectively. Phoswich crystal identification performed using a digital pulse shape discrimination algorithm yielded an average 8% error. At 511 keV, an energy resolution of 17-21% was obtained, while coincidence timing resolution between 4.6 ns and 5.2 ns was achieved. The characteristics of this new LGSO-based phoswich detector module are expected to improve the LabPET scanner performance. The higher stopping power would increase the detection efficiency. The better timing resolution would also allow the use of a narrower coincidence window, thus minimizing the random event rate. Altogether, these two improvements will significantly enhance the noise equivalent count rate performance of an all LGSO-based LabPET scanner.

Up-and-down designs for phase I clinical trials

PubMed Central

Liu, Suyu; Cai, Chunyan; Ning, Jing

2014-01-01

Various up-and-down designs have been proposed to improve the operating characteristics of the traditional “3+3” design, but they have been of limited use in practice. A major impediment to the adoption of the improved up-and-down designs is a lack of general guidance and a comprehensive assessment of the operating characteristics of these designs under practical clinical settings. To fill this gap, we review six up-and-down designs: the “3+3” design, accelerated titration design, biased coin design, k-in-a-row design, group up-and-down design and cumulative group up-and-down design. We conduct comprehensive simulation studies to evaluate their operating characteristics under various practical settings, and compare their performance to a theoretical optimal bound of nonparametric designs. The results show that the cumulative group up-and-down design has the best overall performance in terms of selecting the maximum tolerated dose (MTD), assigning patients to the MTD and patient safety. Its performance is generally close to the upper bound of nonparametric designs, but improvement seems possible in some cases. PMID:23856381

A Study on Rotordynamic Characteristics of Swirl Brakes for Three Types of Seals

NASA Astrophysics Data System (ADS)

Xu, Wanjun; Yang, Jiangang

2017-03-01

In order to understand swirl brakes mechanisms and their influence on rotordynamic characteristics for different types of seals, a three-dimensional flow numerical simulation was presented. Three typical seals including labyrinth seal, fully partitioned damper seal and hole-pattern seal were compared under three inlet conditions of no preswirl, preswirl and preswirl with swirl brakes. FAN boundary condition was used to provide inlet preswirl. A modified identification method of effective damping was proposed. Feasibility of the swirl brakes on improving performance of damper seals was discussed. The results show that the swirl brakes influence the seal stability characteristics with whirl frequency. For the labyrinth seal the swirl brakes reverse the sign of effective damping at low frequency and improve the seal stability performance in a wide frequency range. The swirl brakes also improve the damper seals’ stability performance by increasing the low frequency effective damping and reducing their crossover frequency. Further results indicate the swirl brakes affect the rotational direction of the maximum (minimum) pressure positions and enhance the stability of the seals by reducing tangential force in each cavity.

Using a Malcolm Baldrige framework to understand high-performing clinical microsystems.

PubMed

Foster, Tina C; Johnson, Julie K; Nelson, Eugene C; Batalden, Paul B

2007-10-01

BACKGROUND, OBJECTIVES AND METHOD: The Malcolm Baldrige National Quality Award (MBNQA) provides a set of criteria for organisational quality assessment and improvement that has been used by thousands of business, healthcare and educational organisations for more than a decade. The criteria can be used as a tool for self-evaluation, and are widely recognised as a robust framework for design and evaluation of healthcare systems. The clinical microsystem, as an organisational construct, is a systems approach for providing clinical care based on theories from organisational development, leadership and improvement. This study compared the MBNQA criteria for healthcare and the success factors of high-performing clinical microsystems to (1) determine whether microsystem success characteristics cover the same range of issues addressed by the Baldrige criteria and (2) examine whether this comparison might better inform our understanding of either framework. Both Baldrige criteria and microsystem success characteristics cover a wide range of areas crucial to high performance. Those particularly called out by this analysis are organisational leadership, work systems and service processes from a Baldrige standpoint, and leadership, performance results, process improvement, and information and information technology from the microsystem success characteristics view. Although in many cases the relationship between Baldrige criteria and microsystem success characteristics are obvious, in others the analysis points to ways in which the Baldrige criteria might be better understood and worked with by a microsystem through the design of work systems and a deep understanding of processes. Several tools are available for those who wish to engage in self-assessment based on MBNQA criteria and microsystem characteristics.

Using a Malcolm Baldrige framework to understand high‐performing clinical microsystems

PubMed Central

Foster, Tina C; Johnson, Julie K; Nelson, Eugene C; Batalden, Paul B

2007-01-01

Background, objectives and method The Malcolm Baldrige National Quality Award (MBNQA) provides a set of criteria for organisational quality assessment and improvement that has been used by thousands of business, healthcare and educational organisations for more than a decade. The criteria can be used as a tool for self‐evaluation, and are widely recognised as a robust framework for design and evaluation of healthcare systems. The clinical microsystem, as an organisational construct, is a systems approach for providing clinical care based on theories from organisational development, leadership and improvement. This study compared the MBNQA criteria for healthcare and the success factors of high‐performing clinical microsystems to (1) determine whether microsystem success characteristics cover the same range of issues addressed by the Baldrige criteria and (2) examine whether this comparison might better inform our understanding of either framework. Results and conclusions Both Baldrige criteria and microsystem success characteristics cover a wide range of areas crucial to high performance. Those particularly called out by this analysis are organisational leadership, work systems and service processes from a Baldrige standpoint, and leadership, performance results, process improvement, and information and information technology from the microsystem success characteristics view. Although in many cases the relationship between Baldrige criteria and microsystem success characteristics are obvious, in others the analysis points to ways in which the Baldrige criteria might be better understood and worked with by a microsystem through the design of work systems and a deep understanding of processes. Several tools are available for those who wish to engage in self‐assessment based on MBNQA criteria and microsystem characteristics. PMID:17913773

Dynamic load-sharing characteristic analysis of face gear power-split gear system based on tooth contact characteristics

NASA Astrophysics Data System (ADS)

Dong, Hao; Hu, Yahui

2018-04-01

The bend-torsion coupling dynamics load-sharing model of the helicopter face gear split torque transmission system is established by using concentrated quality standard, to analyzing the dynamic load-sharing characteristic. The mathematical models include nonlinear support stiffness, time-varying meshing stiffness, damping, gear backlash. The results showed that the errors collectively influenced the load sharing characteristics, only reduce a certain error, it is never fully reached the perfect loading sharing characteristics. The system load-sharing performance can be improved through floating shaft support. The above-method will provide a theoretical basis and data support for its dynamic performance optimization design.

Numerical Investigation on Aerodynamic and Combustion Performance of Chevron Mixer Inside an Afterburner.

PubMed

Yong, Shan; JingZhou, Zhang; Yameng, Wang

2014-11-01

To improve the performance of the afterburner for the turbofan engine, an innovative type of mixer, namely, the chevron mixer, was considered to enhance the mixture between the core flow and the bypass flow. Computational fluid dynamics (CFD) simulations investigated the aerodynamic performances and combustion characteristics of the chevron mixer inside a typical afterburner. Three types of mixer, namely, CC (chevrons tilted into core flow), CB (chevrons tilted into bypass flow), and CA (chevrons tilted into core flow and bypass flow alternately), respectively, were studied on the aerodynamic performances of mixing process. The chevrons arrangement has significant effect on the mixing characteristics and the CA mode seems to be advantageous for the generation of the stronger streamwise vortices with lower aerodynamic loss. Further investigations on combustion characteristics for CA mode were performed. Calculation results reveal that the local temperature distribution at the leading edge section of flame holder is improved under the action of streamwise vortices shedding from chevron mixers. Consequently, the combustion efficiency increased by 3.5% compared with confluent mixer under the same fuel supply scheme.

Performance Characteristics of Flush and Shielded Auxiliary Exits at Mach Numbers of 1.5 to 2.0

NASA Technical Reports Server (NTRS)

Abdalla, Kaleel L.

1959-01-01

The performance characteristics of several flush and shielded auxiliary exits were investigated at Mach numbers of 1.5 to 2.0, and jet pressure ratios from jet off to 10. The results indicate that the shielded configurations produced better overall performance than the corresponding flush exits over the Mach-number and pressure-ratio ranges investigated. Furthermore, the full-length shielded exit was highest in performance of all the configurations. The flat-exit nozzle block provided considerably improved performance compared with the curved-exit nozzle block.

Training employees as a management attribute of successful companies.

PubMed

Khumalo, R

2001-12-01

This paper discusses training as an important attribute of successful companies and identified as characteristic of excellent Zimbabwean companies. Although confident this attribute contributes to successful performance by companies in which it is applied, it is possible that contributions could be more effective were all characteristics implemented collectively. However, the research suggests that training alone can offer significant improvement in employees' performance.

Improving International-Level Chess Players' Performance with an Acceptance-Based Protocol: Preliminary Findings

ERIC Educational Resources Information Center

Ruiz, Francisco J.; Luciano, Carmen

2012-01-01

This study compared an individual, 4-hr intervention based on acceptance and commitment therapy (ACT) versus a no-contact control condition in improving the performance of international-level chess players. Five participants received the brief ACT protocol, with each matched to another chess player with similar characteristics in the control…

Combustion Characteristics Analysis of Improved Combustor Structure of Micro Turbine Engine

NASA Astrophysics Data System (ADS)

Chen, Hai

2018-05-01

In order to improve the performance of micro combustor, the 60 slots of the original combustor were modified into 120 slots for the MIT 6-wafer micro-combustor. The performance of the micro combustor with the improved and original design was compared through numerical simulation, and stable operating ranges was studied. It was found that the improved combustor can stabilize the flame under the condition of higher fuel/air mixture mass flow rate.

CF6 Jet Engine Performance Improvement Program: High Pressure Turbine Aerodynamic Performance Improvement

NASA Technical Reports Server (NTRS)

Fasching, W. A.

1980-01-01

The improved single shank high pressure turbine design was evaluated in component tests consisting of performance, heat transfer and mechanical tests, and in core engine tests. The instrumented core engine test verified the thermal, mechanical, and aeromechanical characteristics of the improved turbine design. An endurance test subjected the improved single shank turbine to 1000 simulated flight cycles, the equivalent of approximately 3000 hours of typical airline service. Initial back-to-back engine tests demonstrated an improvement in cruise sfc of 1.3% and a reduction in exhaust gas temperature of 10 C. An additional improvement of 0.3% in cruise sfc and 6 C in EGT is projected for long service engines.

Performance, gut morphology and carcass characteristics of fattening rabbits as affected by particle size of pelleted diets.

PubMed

Tufarelli, Vincenzo; Desantis, Salvatore; Zizza, Sara; Laudadio, Vito

2010-10-01

A review of past literature revealed inconsistencies in recommended feed particle size for optimal growth and productive performance of rabbits. Changing diet formulation and subsequent processing conditions may improve pellet texture and potentially affect rabbit performance. In the current study, two isoenergetic and isonitrogenous pelleted diets were formulated, which varied in the particle size of the concentrates (2 and 8 mm, respectively). The objective was to evaluate the effect of different particle sizes of compound diets on performance, nutrient utilisation, gut morphology, and carcass characteristics of fattening Italian White breed rabbits. The finely ground diet led to a significant improvement in feed efficiency and apparent digestibility of crude protein, ether extract, crude fibre and NDF, without any negative effect on gut morphology. Furthermore, a smaller particle size of concentrates in pelleted diets improved carcass traits. Meat colour parameters showed significant differences in longissimus lumborum and biceps femoris due to dietary treatments, but in both muscles pH values 1 h and 24 h after slaughter remained unchanged. It is concluded that a finely ground pelleted diet can be used to improve growth performance of rabbits without affecting carcass parameters.

Test and evaluation of constant-flow devices for use in SSN AFFF proportioning systems. Interim report, January-May 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, F.W.; Back, G.G.; Burns, R.E.

1986-11-04

Constant flow devices, which deliver a constant flow of liquid over a range of upstream and downstream pressures, have been suggested as an alternative to orifice plates for proportioning AFFF in SSN 21 fire-suppression systems. Operational and performance characteristics of two lightweight, inexpensive, commercially available constant-flow devices have significant advantages over orifice plates. Both models tested, however, showed performance degradation when subjected to simulated service conditions. A constant flow device with improved resistance to wear and to AFFF exposure is desirable. Since the constant-flow control devices tested improves proportioning efficiency but do not have optimum characteristics, investigation of improved devicesmore » or methods is recommended.« less

Influence of gate overlap engineering on ambipolar and high frequency characteristics of tunnel-CNTFET

NASA Astrophysics Data System (ADS)

Shaker, Ahmed; Ossaimee, Mahmoud; Zekry, A.; Abouelatta, Mohamed

2015-10-01

In this paper, we have investigated the effect of gate overlapping-on-drain on the ambipolar behavior and high frequency performance of tunnel CNTFET (T-CNTFET). It is found that gate overlapping-on-drain suppresses the ambipolar behavior and improves OFF-state current. The simulation results show that there is an optimum choice for the overlapped length. On the other hand, this overlap deteriorates the high frequency performance. The high frequency figure of merit is analyzed in terms of the unit-gain cutoff frequency (fT). Further, we propose two different approaches to improve the high frequency performance of the overlapped T-CNTFET. The first one is based on inserting a high-dielectric constant material below the overlapped part of the gate and the second is based on depositing a different work function gate metal for the overlapped region. The two solutions show very good improvement in the high frequency performance with maintaining the suppression of the ambipolar characteristics.

Performance Testing of Yardney MCMB-LiNiCoAlO2 Lithium-ion Cells Possessing Electrolytes with Improved Safety Characteristics

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Whitcanack, Larry D.; Krause, Frederick C.; Hwang, Constanza; Bugga, Ratnakumar V.; Santee, Stuart; Puglia, Frank J.; Gitzendanner, Rob

2012-01-01

Many future NASA missions aimed at exploring the Moon and Mars require high specific energy rechargeable batteries that possess enhanced safety characteristics. There is also a strong desire to develop Li-ion batteries with improved safety characteristics for terrestrial applications, most notably for HEV and PHEV automotive applications. In previous work focused upon evaluating various potential flame retardant additives1, triphenyl phosphate (TPP)2 was observed to have the most desirable attributes, including good life characteristics and resilience to high voltage operation. We have employed a number of approaches in the design of promising TPP-based electrolytes with improved safety, including: (a) varying the flame retardant additive (FRA) content (from 5 to 15%), (b) the use of fluorinated co-solvents, (c) the use of additives to improve compatibility, and (c) the use of ester co-solvents to decrease the viscosity and increase the conductivity. In recent work, we have demonstrated a number of these electrolyte formulations to be compatible with a number of chemistries, including: MCMB carbon-LiNi0.8Co0.2O2, graphite-LiNi0.8Co0.15Al0.05O2, Li-Li(Li0.17Ni 0.25 Mn 0.58 )O2, Li-LiNiCoMnO2 and graphite- LiNiCoMnO2.3,4 In the current study, we have demonstrated the performance of a number of TPP-containing electrolytes in 7 Ah prototype MCMB-LiNiCoO2 cells. We will describe the results of a number of performance tests, including: a) 100% DOD cycle life testing at various temperatures, b) discharge rate characterization as a function of temperature, c) charge rate characterization as a function of temperature, and d) impedance as a function of temperature. In addition to displaying good life characteristics, being comparable to baseline chemistries, a number of cells were observed to provide good performance over a wide temperature range.

Current food safety management systems in fish-exporting companies require further improvements to adequately cope with contextual pressure: case study.

PubMed

Onjong, Hillary Adawo; Wangoh, John; Njage, Patrick Murigu Kamau

2014-10-01

Fish-processing plants still face food safety (FS) challenges worldwide despite the existence of several quality assurance standards and food safety management systems/s (FSMSs). This study assessed performance of FSMS in fish exporting sector considering pressure from the context in which they operate. A FSMS diagnostic tool with checklist was used to assess the context, FSMS, and FS output in 9 Kenyan fish exporting companies. Majority (67%) companies operated at moderate- to high-risk context but with an average performance in control and assurance activities. This situation could be insufficient to deal with ambiguity, uncertainty, and vulnerability issues in the context characteristics. Contextual risk posed by product characteristics (nature of raw materials) and chain environment characteristics was high. Risk posed by the chain environment characteristics, low power in supplier relationships, and low degree of authority in customer relationships was high. Lack of authority in relationship with suppliers would lead to high raw material risk situation. Even though cooling facilities, a key control activity, was at an advanced level, there was inadequate packaging intervention equipment which coupled with inadequate physical intervention equipment could lead to further weakened FSMS performance. For the fish companies to improve their FSMS to higher level and enhance predictability, they should base their FSMS on scientific information sources, historical results, and own experimental trials in their preventive, intervention, and monitoring systems. Specific suggestions are derived for improvements toward higher FSMS activity levels or lower risk levels in context characteristics. Weak areas in performance of control and assurance activities in export fish-processing sector already implementing current quality assurance guidelines and standards were studied taking into consideration contextual pressure wherein the companies operate. Important mitigation measures toward improved contextual risk, core assurance, and control activities irrespective of applied food safety management systems in fish industries were suggested. © 2014 Institute of Food Technologists®

Institutional and Economic Determinants of Public Health System Performance

PubMed Central

Mays, Glen P.; McHugh, Megan C.; Shim, Kyumin; Perry, Natalie; Lenaway, Dennis; Halverson, Paul K.; Moonesinghe, Ramal

2006-01-01

Objectives. Although a growing body of evidence demonstrates that availability and quality of essential public health services vary widely across communities, relatively little is known about the factors that give rise to these variations. We examined the association of institutional, financial, and community characteristics of local public health delivery systems and the performance of essential services. Methods. Performance measures were collected from local public health systems in 7 states and combined with secondary data sources. Multivariate, linear, and nonlinear regression models were used to estimate associations between system characteristics and the performance of essential services. Results. Performance varied significantly with the size, financial resources, and organizational structure of local public health systems, with some public health services appearing more sensitive to these characteristics than others. Staffing levels and community characteristics also appeared to be related to the performance of selected services. Conclusions. Reconfiguring the organization and financing of public health systems in some communities—such as through consolidation and enhanced intergovernmental coordination—may hold promise for improving the performance of essential services. PMID:16449584

Improved Hot Carrier Reliability Characteristics of Metal Oxide Semiconductor Field Effect Transistors with High-k Gate Dielectric by Using High Pressure Deuterium Post Metallization Annealing

NASA Astrophysics Data System (ADS)

Park, Hokyung; Choi, Rino; Lee, Byoung Hun; Hwang, Hyunsang

2007-09-01

High pressure deuterium annealing on the hot carrier reliability characteristics of HfSiO metal oxide semiconductor field effect transistor (MOSFET) was investigated. Comparing with the conventional forming gas (H2/Ar=10%/96%, 480 °C, 30 min) annealed sample, MOSFET annealed in 5 atm pure deuterium ambient at 400 °C showed the improvement of linear drain current, reduction of interface trap density, and improvement of the hot carrier reliability characteristics. These improvements can be attributed to the effective passivation of the interface trap site after high pressure annealing and heavy mass effect of deuterium. These results indicate that high pressure pure deuterium annealing can be a promising process for improving device performance as well as hot carrier reliability, together.

Uncertain behaviours of integrated circuits improve computational performance.

PubMed

Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

2015-11-20

Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance.

Improving the performance of heterogeneous multi-core processors by modifying the cache coherence protocol

NASA Astrophysics Data System (ADS)

Fang, Juan; Hao, Xiaoting; Fan, Qingwen; Chang, Zeqing; Song, Shuying

2017-05-01

In the Heterogeneous multi-core architecture, CPU and GPU processor are integrated on the same chip, which poses a new challenge to the last-level cache management. In this architecture, the CPU application and the GPU application execute concurrently, accessing the last-level cache. CPU and GPU have different memory access characteristics, so that they have differences in the sensitivity of last-level cache (LLC) capacity. For many CPU applications, a reduced share of the LLC could lead to significant performance degradation. On the contrary, GPU applications can tolerate increase in memory access latency when there is sufficient thread-level parallelism. Taking into account the GPU program memory latency tolerance characteristics, this paper presents a method that let GPU applications can access to memory directly, leaving lots of LLC space for CPU applications, in improving the performance of CPU applications and does not affect the performance of GPU applications. When the CPU application is cache sensitive, and the GPU application is insensitive to the cache, the overall performance of the system is improved significantly.

Review of Proposed Automotive Carburetor Concepts for Improved Fuel Economy

DOT National Transportation Integrated Search

1975-03-01

This report summarizes available information pertaining to proposed concepts for improved automotive carburetors. In particular, information is provided which depicts the development and performance characteristics of a selected number of advanced, n...

Improved breakdown characteristics of monolithically integrated III-nitride HEMT-LED devices using carbon doping

NASA Astrophysics Data System (ADS)

Liu, Chao; Liu, Zhaojun; Huang, Tongde; Ma, Jun; May Lau, Kei

2015-03-01

We report selective growth of AlGaN/GaN high electron mobility transistors (HEMTs) on InGaN/GaN light emitting diodes (LEDs) for monolithic integration of III-nitride HEMT and LED devices (HEMT-LED). To improve the breakdown characteristics of the integrated HEMT-LED devices, carbon doping was introduced in the HEMT buffer by controlling the growth pressure and V/III ratio. The breakdown voltage of the fabricated HEMTs grown on LEDs was enhanced, without degradation of the HEMT DC performance. The improved breakdown characteristics can be attributed to better isolation of the HEMT from the underlying conductive p-GaN layer of the LED structure.

Aerodynamics of High-Lift Configuration Civil Aircraft Model in JAXA

NASA Astrophysics Data System (ADS)

Yokokawa, Yuzuru; Murayama, Mitsuhiro; Ito, Takeshi; Yamamoto, Kazuomi

This paper presents basic aerodynamics and stall characteristics of the high-lift configuration aircraft model JSM (JAXA Standard Model). During research process of developing high-lift system design method, wind tunnel testing at JAXA 6.5m by 5.5m low-speed wind tunnel and Navier-Stokes computation on unstructured hybrid mesh were performed for a realistic configuration aircraft model equipped with high-lift devices, fuselage, nacelle-pylon, slat tracks and Flap Track Fairings (FTF), which was assumed 100 passenger class modern commercial transport aircraft. The testing and the computation aimed to understand flow physics and then to obtain some guidelines for designing a high performance high-lift system. As a result of the testing, Reynolds number effects within linear region and stall region were observed. Analysis of static pressure distribution and flow visualization gave the knowledge to understand the aerodynamic performance. CFD could capture the whole characteristics of basic aerodynamics and clarify flow mechanism which governs stall characteristics even for complicated geometry and its flow field. This collaborative work between wind tunnel testing and CFD is advantageous for improving or has improved the aerodynamic performance.

A national evaluation of Safe Schools/Healthy Students: outcomes and influences.

PubMed

Derzon, James H; Yu, Ping; Ellis, Bruce; Xiong, Sharon; Arroyo, Carmen; Mannix, Danyelle; Wells, Michael E; Hill, Gary; Rollison, Julia

2012-05-01

The Safe Schools/Healthy Students (SS/HS) Initiative has awarded over $2 billion in grants to more than 350 school districts in partnership with local mental health, law enforcement, and juvenile justice agencies. To estimate the impact of grantee characteristics, grant operations, and near-term outcomes in reducing violence and substance use, promoting mental health, and enhancing school safety, logged odds ratios (LORs) were calculated contrasting Year 3 with Baseline performance from grantee-provided data on seven outcome measures. After comparing grantee performance across outcomes and outcomes across grantees, the LORs were entered as dependent variables in a series of meta-regressions in which grantee characteristics, grant operations, and near-term outcomes were tested after controlling for pre-grant characteristics. Findings indicate that the SS/HS Initiative significantly improved most outcomes, that within-grantee performance varied greatly by outcome, and that random-effects meta-regression appreciably decreased the variance available for modeling. The approach demonstrates that the SS/HS Initiative is effective and that locally collected performance data can be used to estimate grantee success in improving youth outcomes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis and optimisation of lateral thin-film silicon-on-insulator (SOI) PMOS transistor with an NBL layer in the drift region

NASA Astrophysics Data System (ADS)

Cortés, I.; Toulon, G.; Morancho, F.; Flores, D.; Hugonnard-Bruyère, E.; Villard, B.

2012-04-01

This paper analyses the experimental results of voltage capability (VBR > 120 V) and output characteristics of a new lateral power P-channel MOS transistors manufactured on a 0.18 μm SOI CMOS technology by means of TCAD numerical simulations. The proposed LDPMOS structures have an N-type buried layer (NBL) inserted in the P-well drift region with the purpose of increasing the RESURF effectiveness and improving the static characteristics (Ron-sp/VBR trade-off) and the device switching performance. Some architecture modifications are also proposed in this paper to further improve the performance of fabricated transistors.

An Examination of Differences in Division I FBS Student-Athlete Academic and Athletic Performance

ERIC Educational Resources Information Center

Nichols, Marissa K.

2017-01-01

The student-athlete literature is rife with studies that examine the factors that appear to improve or inhibit academic or athletic performance. However, internal characteristics that may influence variations in performance have been understudied, and athletic performance tends to be examined separately from academic performance. This study…

Improved Performance of h-BN Encapsulated Double Gate Graphene Nanomesh Field Effect Transistor for Short Channel Length

NASA Astrophysics Data System (ADS)

Tiwari, Durgesh Laxman; Sivasankaran, K.

This paper presents improved performance of Double Gate Graphene Nanomesh Field Effect Transistor (DG-GNMFET) with h-BN as substrate and gate oxide material. The DC characteristics of 0.95μm and 5nm channel length devices are studied for SiO2 and h-BN substrate and oxide material. For analyzing the ballistic behavior of electron for 5nm channel length, von Neumann boundary condition is considered near source and drain contact region. The simulated results show improved saturation current for h-BN encapsulated structure with two times higher on current value (0.375 for SiO2 and 0.621 for h-BN) as compared to SiO2 encapsulated structure. The obtained result shows h-BN to be a better substrate and oxide material for graphene electronics with improved device characteristics.

Factors associated with the impact of quality improvement collaboratives in mental healthcare: An exploratory study

PubMed Central

2012-01-01

Background Quality improvement collaboratives (QICs) bring together groups of healthcare professionals to work in a structured manner to improve the quality of healthcare delivery within particular domains. We explored which characteristics of the composition, participation, functioning, and organization of these collaboratives related to changes in the healthcare for patients with anxiety disorders, dual diagnosis, or schizophrenia. Methods We studied three QICs involving 29 quality improvement (QI) teams representing a number of mental healthcare organizations in the Netherlands. The aims of the three QICs were the implementation of multidisciplinary practice guidelines in the domains of anxiety disorders, dual diagnosis, and schizophrenia, respectively. We used eight performance indicators to assess the impact of the QI teams on self-reported patient outcomes and process of care outcomes for 1,346 patients. The QI team members completed a questionnaire on the characteristics of the composition, participation in a national program, functioning, and organizational context for their teams. It was expected that an association would be found between these team characteristics and the quality of care for patients with anxiety disorders, dual diagnosis, and schizophrenia. Results No consistent patterns of association emerged. Theory-based factors did not perform better than practice-based factors. However, QI teams that received support from their management and both active and inspirational team leadership showed better results. Rather surprisingly, a lower average level of education among the team members was associated with better results, although less consistently than the management and leadership characteristics. Team views with regard to the QI goals of the team and attitudes towards multidisciplinary practice guidelines did not correlate with team success. Conclusions No general conclusions about the impact of the characteristics of QI teams on the quality of healthcare can be drawn, but support of the management and active, inspirational team leadership appear to be important. Not only patient outcomes but also the performance indicators of monitoring and screening/assessment showed improvement in many but not all of the QI teams with such characteristics. More studies are needed to identify factors associated with the impact of multidisciplinary practice guidelines in mental healthcare. PMID:22230594

Fracture properties and fatigue cracking resistance of asphalt binders.

DOT National Transportation Integrated Search

2012-03-01

Several different types of modifiers are increasingly bring used to improve the performance of asphalt binders or to : achieve desired mixture production characteristics (e.g., Warm Mix Asphalt). However, current Superpave : performance specification...

Are NCLB's Measures, Incentives, and Improvement Strategies the Right Ones for the Nation's Low-Performing High Schools?

ERIC Educational Resources Information Center

Balfanz, Robert; Legters, Nettie; West, Thomas C.; Weber, Lisa M.

2007-01-01

This article examines the extent to which adequate yearly progress (AYP) is a valid and reliable indicator of improvement in low-performing high schools. For a random subsample of 202 high schools, the authors investigate the school characteristics and the federal and state policy contexts that influence their AYP status. Logistic regression…

Day-Ahead Crude Oil Price Forecasting Using a Novel Morphological Component Analysis Based Model

PubMed Central

Zhu, Qing; Zou, Yingchao; Lai, Kin Keung

2014-01-01

As a typical nonlinear and dynamic system, the crude oil price movement is difficult to predict and its accurate forecasting remains the subject of intense research activity. Recent empirical evidence suggests that the multiscale data characteristics in the price movement are another important stylized fact. The incorporation of mixture of data characteristics in the time scale domain during the modelling process can lead to significant performance improvement. This paper proposes a novel morphological component analysis based hybrid methodology for modeling the multiscale heterogeneous characteristics of the price movement in the crude oil markets. Empirical studies in two representative benchmark crude oil markets reveal the existence of multiscale heterogeneous microdata structure. The significant performance improvement of the proposed algorithm incorporating the heterogeneous data characteristics, against benchmark random walk, ARMA, and SVR models, is also attributed to the innovative methodology proposed to incorporate this important stylized fact during the modelling process. Meanwhile, work in this paper offers additional insights into the heterogeneous market microstructure with economic viable interpretations. PMID:25061614

Day-ahead crude oil price forecasting using a novel morphological component analysis based model.

PubMed

Zhu, Qing; He, Kaijian; Zou, Yingchao; Lai, Kin Keung

2014-01-01

As a typical nonlinear and dynamic system, the crude oil price movement is difficult to predict and its accurate forecasting remains the subject of intense research activity. Recent empirical evidence suggests that the multiscale data characteristics in the price movement are another important stylized fact. The incorporation of mixture of data characteristics in the time scale domain during the modelling process can lead to significant performance improvement. This paper proposes a novel morphological component analysis based hybrid methodology for modeling the multiscale heterogeneous characteristics of the price movement in the crude oil markets. Empirical studies in two representative benchmark crude oil markets reveal the existence of multiscale heterogeneous microdata structure. The significant performance improvement of the proposed algorithm incorporating the heterogeneous data characteristics, against benchmark random walk, ARMA, and SVR models, is also attributed to the innovative methodology proposed to incorporate this important stylized fact during the modelling process. Meanwhile, work in this paper offers additional insights into the heterogeneous market microstructure with economic viable interpretations.

Note: An improved solenoid driver valve for miniature shock tubes.

PubMed

Lynch, P T

2016-05-01

A solenoid driver valve has been built to improve the operating performance of diaphragmless shock tubes, which are used for high pressure, high temperature chemical kinetics, and fluid mechanics studies. For shock tube driver application, the most important characteristics are those of sealing, strength, and quality of the generated shock waves and repeatability of opening characteristics and therefore subsequent post-shock conditions. The main features of the new driver valve are a face o-ring sealing design of the valve, the large internal volume, and through inserts near the solenoid core: adjustable opening characteristics of the valve.

Electromagnetic Modelling of MMIC CPWs for High Frequency Applications

NASA Astrophysics Data System (ADS)

Sinulingga, E. P.; Kyabaggu, P. B. K.; Rezazadeh, A. A.

2018-02-01

Realising the theoretical electrical characteristics of components through modelling can be carried out using computer-aided design (CAD) simulation tools. If the simulation model provides the expected characteristics, the fabrication process of Monolithic Microwave Integrated Circuit (MMIC) can be performed for experimental verification purposes. Therefore improvements can be suggested before mass fabrication takes place. This research concentrates on development of MMIC technology by providing accurate predictions of the characteristics of MMIC components using an improved Electromagnetic (EM) modelling technique. The knowledge acquired from the modelling and characterisation process in this work can be adopted by circuit designers for various high frequency applications.

ATS-5 millimeter wave propagation measurements

NASA Technical Reports Server (NTRS)

Ippolito, L. J.

1973-01-01

Long term experimental measurements to determine the propagation characteristics of 15 and 32 GHz earth-space links and to evaluate performance characteristics of operational millimeter wave systems are reported. The ATS 5 millimeter wave experimental link experienced attenuation and fading characteristics as a function of rainfall rate and other meteorological parameters. A method of site selection for the lowest attenuation rainfall rate improved reception tremendously.

Control of Industrial Safety Based on Dynamic Characteristics of a Safety Budget-Industrial Accident Rate Model in Republic of Korea.

PubMed

Choi, Gi Heung; Loh, Byoung Gook

2017-06-01

Despite the recent efforts to prevent industrial accidents in the Republic of Korea, the industrial accident rate has not improved much. Industrial safety policies and safety management are also known to be inefficient. This study focused on dynamic characteristics of industrial safety systems and their effects on safety performance in the Republic of Korea. Such dynamic characteristics are particularly important for restructuring of the industrial safety system. The effects of damping and elastic characteristics of the industrial safety system model on safety performance were examined and feedback control performance was explained in view of cost and benefit. The implications on safety policies of restructuring the industrial safety system were also explored. A strong correlation between the safety budget and the industrial accident rate enabled modeling of an industrial safety system with these variables as the input and the output, respectively. A more effective and efficient industrial safety system could be realized by having weaker elastic characteristics and stronger damping characteristics in it. A substantial decrease in total social cost is expected as the industrial safety system is restructured accordingly. A simple feedback control with proportional-integral action is effective in prevention of industrial accidents. Securing a lower level of elastic industrial accident-driving energy appears to have dominant effects on the control performance compared with the damping effort to dissipate such energy. More attention needs to be directed towards physical and social feedbacks that have prolonged cumulative effects. Suggestions for further improvement of the safety system including physical and social feedbacks are also made.

Solid Polymer Electrolyte (SPE) fuel cell technology program

NASA Technical Reports Server (NTRS)

1978-01-01

Many previously demonstrated improved fuel cell features were consolidated to (1) obtain a better understanding of the observed characteristics of the operating laboratory-sized cells; (2) evaluate appropriate improved fuel cell features in 0.7 sq ft cell hardware; and (3) study the resultant fuel cell capability and determine its impact on various potential fuel cell space missions. The observed performance characteristics of the fuel cell at high temperatures and high current densities were matched with a theoretical model based on the change in Gibbs free energy voltage with respect to temperature and internal resistance change with current density. Excellent agreement between the observed and model performance was obtained. The observed performance decay with operational time on cells with very low noble metal loadings (0.05 mg/sq cm) were shown to be related to loss in surface area. Cells with the baseline amount of noble catalyst electrode loading demonstrated over 40,000 hours of stable performance.

Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus Characteristics

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and amplitude of the signal characteristics of the stochastic noise signals on maximizing balance performance will have a significant impact in its development as a unique system to aid recovery of function in astronauts after long duration space flight or for people with balance disorders.

An eight-week golf-specific exercise program improves physical characteristics, swing mechanics, and golf performance in recreational golfers.

PubMed

Lephart, Scott M; Smoliga, James M; Myers, Joseph B; Sell, Timothy C; Tsai, Yung-Shen

2007-08-01

The purpose of this study was to determine the effects of an 8-week golf-specific exercise program on physical characteristics, swing mechanics, and golf performance. Fifteen trained male golfers (47.2 +/- 11.4 years, 178.8 +/- 5.8 cm, 86.7 +/- 9.0 kg, and 12.1 +/- 6.4 U.S. Golf Association handicap) were recruited. Trained golfers was defined operationally as golfers who play a round of golf at least 2-3 times per week and practice at the driving range at least 2-3 times per week during the regular golf season. Subjects performed a golf-specific conditioning program 3-4 times per week for 8 weeks during the off-season in order to enhance physical characteristics. Pre- and posttraining testing of participants included assessments of strength (torso, shoulder, and hip), flexibility, balance, swing mechanics, and golf performance. Following training, torso rotational strength and hip abduction strength were improved significantly (p < 0.05). Torso, shoulder, and hip flexibility improved significantly in all flexibility measurements taken (p < 0.05). Balance was improved significantly in 3 of 12 measurements, with the remainder of the variables demonstrating a nonsignificant trend for improvement. The magnitude of upper-torso axial rotation was decreased at the acceleration (p = 0.015) and impact points (p =0.043), and the magnitude of pelvis axial rotation was decreased at the top (p = 0.031) and acceleration points (p = 0.036). Upper-torso axial rotational velocity was increased significantly at the acceleration point of the golf swing (p = 0.009). Subjects increased average club velocity (p = 0.001), ball velocity (p = 0.001), carry distance (p = 0.001), and total distance (p = 0.001). These results indicate that a golf-specific exercise program improves strength, flexibility, and balance in golfers. These improvements result in increased upper-torso axial rotational velocity, which results in increased club head velocity, ball velocity, and driving distance.

Nanocomposites for Machining Tools

PubMed Central

Loginov, Pavel; Mishnaevsky, Leon; Levashov, Evgeny

2017-01-01

Machining tools are used in many areas of production. To a considerable extent, the performance characteristics of the tools determine the quality and cost of obtained products. The main materials used for producing machining tools are steel, cemented carbides, ceramics and superhard materials. A promising way to improve the performance characteristics of these materials is to design new nanocomposites based on them. The application of micromechanical modeling during the elaboration of composite materials for machining tools can reduce the financial and time costs for development of new tools, with enhanced performance. This article reviews the main groups of nanocomposites for machining tools and their performance. PMID:29027926

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

NASA Technical Reports Server (NTRS)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

The design and operating characteristics of an advanced 30-kW ammonia arcjet engine

NASA Technical Reports Server (NTRS)

Deininger, William D.; Pivirotto, Thomas J.; Brophy, John R.

1987-01-01

Experimental investigations were conducted to evaluate the effects of a contoured nozzle and modified cathode shape on ammonia arcjet engine performance. The contoured nozzle performance data were compared to the performance data of an arcjet which had a 38-deg included-angle, conical nozzle. Thrust improvements of up to 10 percent were demonstrated which corresponded to 3 percent improvements in specific impulse and 10 percent improvements in thrust efficiency. Performance characterizations for the modified cathode tip were conducted with the contoured nozzle arcjet. A uniform 15 percent decrease in arc voltage was demonstrated over a mass flow range of 0.175 to 0.350 g/s. A 4 percent improvement in thrust efficiency was noted at 22.0 kW.

Sensorimotor Adaptability Training Improves Motor and Dual-Task Performance

NASA Technical Reports Server (NTRS)

Bloomberg, J.J.; Peters, B.T.; Mulavara, A.P.; Brady, R.; Batson, C.; Cohen, H.S.

2009-01-01

The overall objective of our project is to develop a sensorimotor adaptability (SA) training program designed to facilitate recovery of functional capabilities when astronauts transition to different gravitational environments. The goal of our current study was to determine if SA training using variation in visual flow and support surface motion produces improved performance in a novel sensory environment and demonstrate the retention characteristics of SA training.

Studies of recognition with multitemporal remote sensor data

NASA Technical Reports Server (NTRS)

Malila, W. A.; Hieber, R. H.; Cicone, R. C.

1975-01-01

Characteristics of multitemporal data and their use in recognition processing were investigated. Principal emphasis was on satellite data collected by the LANDSAT multispectral scanner and on temporal changes throughout a growing season. The effects of spatial misregistration on recognition performance with multitemporal data were examined. A capability to compute probabilities of detection and false alarm was developed and used with simulated distributions for misregistered pixels. Wheat detection was found to be degraded and false alarms increased by misregistration effects. Multitemporal signature characteristics and multitemporal recognition processing were studied to gain insights into problems associated with this approach and possible improvements. Recognition performance with one multitemporal data set displayed marked improvements over results from single-time data.

Improved methods for the measurement and modeling of PV module and system performance for all operating conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, D.L.

1995-11-01

The objective of this work was to develop improved performance model for modules and systems for for all operating conditions for use in module specifications, system and BOS component design, and system rating or monitoring. The approach taken was to identify and quantify the influence of dominant factors of solar irradiance, cell temperature, angle-of-incidence; and solar spectrum; use outdoor test procedures to separate the effects of electrical, thermal, and optical performance; use fundamental cell characteristics to improve analysis; and combine factors in simple model using the common variables.

Development of a test rig for a helium twin-screw compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B. M.; Hu, Z. J.; Zhang, P.

2014-01-29

A large helium cryogenic system is being developed for use in great science projects, such as the International Thermonuclear Experimental Reactor (ITER), Large Helical Device (LHD), and the Experimental Advanced Superconducting Tokamak (EAST). In this cryogenic system, a twin-screw compressor is a key component. Therefore, it is necessary to obtain the compressor performance. To obtain the performance characteristics, a test rig for the compressor has been built. All the important performance parameters, including adiabatic efficiency, volumetric efficiency, oil injection characteristic, and noise characteristic can be acquired with the rig when sensors are installed in the test system. With the testmore » performance, the helium twin-screw compressor can be evaluated. Using these results, the design of the compressor can be improved.« less

SGC Tests for Influence of Material Composition on Compaction Characteristic of Asphalt Mixtures

PubMed Central

Chen, Qun

2013-01-01

Compaction characteristic of the surface layer asphalt mixture (13-type gradation mixture) was studied using Superpave gyratory compactor (SGC) simulative compaction tests. Based on analysis of densification curve of gyratory compaction, influence rules of the contents of mineral aggregates of all sizes and asphalt on compaction characteristic of asphalt mixtures were obtained. SGC Tests show that, for the mixture with a bigger content of asphalt, its density increases faster, that there is an optimal amount of fine aggregates for optimal compaction and that an appropriate amount of mineral powder will improve workability of mixtures, but overmuch mineral powder will make mixtures dry and hard. Conclusions based on SGC tests can provide basis for how to adjust material composition for improving compaction performance of asphalt mixtures, and for the designed asphalt mixture, its compaction performance can be predicted through these conclusions, which also contributes to the choice of compaction schemes. PMID:23818830

SGC tests for influence of material composition on compaction characteristic of asphalt mixtures.

PubMed

Chen, Qun; Li, Yuzhi

2013-01-01

Compaction characteristic of the surface layer asphalt mixture (13-type gradation mixture) was studied using Superpave gyratory compactor (SGC) simulative compaction tests. Based on analysis of densification curve of gyratory compaction, influence rules of the contents of mineral aggregates of all sizes and asphalt on compaction characteristic of asphalt mixtures were obtained. SGC Tests show that, for the mixture with a bigger content of asphalt, its density increases faster, that there is an optimal amount of fine aggregates for optimal compaction and that an appropriate amount of mineral powder will improve workability of mixtures, but overmuch mineral powder will make mixtures dry and hard. Conclusions based on SGC tests can provide basis for how to adjust material composition for improving compaction performance of asphalt mixtures, and for the designed asphalt mixture, its compaction performance can be predicted through these conclusions, which also contributes to the choice of compaction schemes.

Research on the drag reduction performance induced by the counterflowing jet for waverider with variable blunt radii

NASA Astrophysics Data System (ADS)

Li, Shi-bin; Wang, Zhen-guo; Barakos, George N.; Huang, Wei; Steijl, Rene

2016-10-01

Waverider will endure the huge aero-heating in the hypersonic flow, thus, it need be blunt for the leading edge. However, the aerodynamic performance will decrease for the blunt waverider because of the drag hoik. How to improve the aerodynamic performance and reduce the drag and aero-heating is very important. The variable blunt radii method will improve the aerodynamic performance, however, the huge aero-heating and bow shock wave at the head is still serious. In the current study, opposing jet is used in the waverider with variable blunt radii to improve its performance. The three-dimensional coupled implicit Reynolds-averaged Navier-Stokes(RANS) equation and the two equation SST k-ω turbulence model have been utilized to obtain the flow field properties. The numerical method has been validated against the available experimental data in the open literature. The obtained results show that the L/D will drop 7-8% when R changes from 2 to 8. The lift coefficient will increase, and the drag coefficient almost keeps the same when the variable blunt radii method is adopted, and the L/D will increase. The variable blunt radii method is very useful to improve the whole characteristics of blunt waverider and the L/D can improve 3%. The combination of the variable blunt radii method and opposing jet is a novel way to improve the whole performance of blunt waverider, and L/D can improve 4-5%. The aperture as a novel way of opposing jet is suitable for blunt waverider and also useful to improve the aerodynamic and aerothermodynamic characteristics of waverider in the hypersonic flow. There is the optimal P0in/P0 that can make the detached shock wave reattach the lower surface again so that the blunt waverider can get the better aerodynamic performance.

SUM (Service Unit Management): An Organizational Approach To Improved Patient Care.

ERIC Educational Resources Information Center

Jelinek, Richard C.; And Others

To evaluate the effectiveness of Service Unit Management (SUM) in reducing costs, improving quality of care, saving professional nursing time, increasing personnel satisfaction, and setting a stage for further improvements, a national questionnaire survey identified the characteristics of SUM units, and compared the performance of a total of 55…

The influence of training characteristics on the effect of exercise training in patients with coronary artery disease: Systematic review and meta-regression analysis.

PubMed

Kraal, Jos J; Vromen, Tom; Spee, Ruud; Kemps, Hareld M C; Peek, Niels

2017-10-15

Although exercise-based cardiac rehabilitation improves exercise capacity of coronary artery disease patients, it is unclear which training characteristic determines this improvement. Total energy expenditure and its constituent training characteristics (training intensity, session frequency, session duration and programme length) vary considerably among clinical trials, making it hard to compare studies directly. Therefore, we performed a systematic review and meta-regression analysis to assess the effect of total energy expenditure and its constituent training characteristics on exercise capacity. We identified randomised controlled trials comparing continuous aerobic exercise training with usual care for patients with coronary artery disease. Studies were included when training intensity, session frequency, session duration and programme length was described, and exercise capacity was reported in peakVO 2 . Energy expenditure was calculated from the four training characteristics. The effect of training characteristics on exercise capacity was determined using mixed effects linear regression analyses. The analyses were performed with and without total energy expenditure as covariate. Twenty studies were included in the analyses. The mean difference in peakVO 2 between the intervention group and control group was 3.97ml·min -1 ·kg -1 (p<0.01, 95% CI 2.86 to 5.07). Total energy expenditure was significantly related to improvement of exercise capacity (effect size 0.91ml·min -1 ·kg -1 per 100J·kg, p<0.01, 95% CI 0.77 to 1.06), no effect was found for its constituent training characteristics after adjustment for total energy expenditure. We conclude that the design of an exercise programme should primarily be aimed at optimising total energy expenditure rather than on one specific training characteristic. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Alkaline fuel cell performance investigation

NASA Technical Reports Server (NTRS)

Martin, R. E.; Manzo, M. A.

1988-01-01

An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

Alkaline fuel cell performance investigation

NASA Technical Reports Server (NTRS)

Martin, R. E.; Manzo, M. A.

1988-01-01

An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more than two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

The influence of training characteristics on the effect of aerobic exercise training in patients with chronic heart failure: A meta-regression analysis.

PubMed

Vromen, T; Kraal, J J; Kuiper, J; Spee, R F; Peek, N; Kemps, H M

2016-04-01

Although aerobic exercise training has shown to be an effective treatment for chronic heart failure patients, there has been a debate about the design of training programs and which training characteristics are the strongest determinants of improvement in exercise capacity. Therefore, we performed a meta-regression analysis to determine a ranking of the individual effect of the training characteristics on the improvement in exercise capacity of an aerobic exercise training program in chronic heart failure patients. We focused on four training characteristics; session frequency, session duration, training intensity and program length, and their product; total energy expenditure. A systematic literature search was performed for randomized controlled trials comparing continuous aerobic exercise training with usual care. Seventeen unique articles were included in our analysis. Total energy expenditure appeared the only training characteristic with a significant effect on improvement in exercise capacity. However, the results were strongly dominated by one trial (HF-action trial), accounting for 90% of the total patient population and showing controversial results compared to other studies. A repeated analysis excluding the HF-action trial confirmed that the increase in exercise capacity is primarily determined by total energy expenditure, followed by session frequency, session duration and session intensity. These results suggest that the design of a training program requires high total energy expenditure as a main goal. Increases in training frequency and session duration appear to yield the largest improvement in exercise capacity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Engine health monitoring systems: Tools for improved maintenance management in the 1980's

NASA Technical Reports Server (NTRS)

Kimball, J. C.

1981-01-01

The performance monitoring aspect of maintenance, characteristic of the engine health monitoring system are discussed. An overview of the system activities is presented and a summary of programs for improved monitoring in the 1980's are discussed.

Relations between mental health team characteristics and work role performance.

PubMed

Fleury, Marie-Josée; Grenier, Guy; Bamvita, Jean-Marie; Farand, Lambert

2017-01-01

Effective mental health care requires a high performing, interprofessional team. Among 79 mental health teams in Quebec (Canada), this exploratory study aims to 1) determine the association between work role performance and a wide range of variables related to team effectiveness according to the literature, and to 2) using structural equation modelling, assess the covariance between each of these variables as well as the correlation with other exogenous variables. Work role performance was measured with an adapted version of a work role questionnaire. Various independent variables including team manager characteristics, user characteristics, team profiles, clinical activities, organizational culture, network integration strategies and frequency/satisfaction of interactions with other teams or services were analyzed under the structural equation model. The later provided a good fit with the data. Frequent use of standardized procedures and evaluation tools (e.g. screening and assessment tools for mental health disorders) and team manager seniority exerted the most direct effect on work role performance. While network integration strategies had little effect on work role performance, there was a high covariance between this variable and those directly affecting work role performance among mental health teams. The results suggest that the mental healthcare system should apply standardized procedures and evaluation tools and, to a lesser extent, clinical approaches to improve work role performance in mental health teams. Overall, a more systematic implementation of network integration strategies may contribute to improved work role performance in mental health care.

Relations between mental health team characteristics and work role performance

PubMed Central

Grenier, Guy; Bamvita, Jean-Marie; Farand, Lambert

2017-01-01

Effective mental health care requires a high performing, interprofessional team. Among 79 mental health teams in Quebec (Canada), this exploratory study aims to 1) determine the association between work role performance and a wide range of variables related to team effectiveness according to the literature, and to 2) using structural equation modelling, assess the covariance between each of these variables as well as the correlation with other exogenous variables. Work role performance was measured with an adapted version of a work role questionnaire. Various independent variables including team manager characteristics, user characteristics, team profiles, clinical activities, organizational culture, network integration strategies and frequency/satisfaction of interactions with other teams or services were analyzed under the structural equation model. The later provided a good fit with the data. Frequent use of standardized procedures and evaluation tools (e.g. screening and assessment tools for mental health disorders) and team manager seniority exerted the most direct effect on work role performance. While network integration strategies had little effect on work role performance, there was a high covariance between this variable and those directly affecting work role performance among mental health teams. The results suggest that the mental healthcare system should apply standardized procedures and evaluation tools and, to a lesser extent, clinical approaches to improve work role performance in mental health teams. Overall, a more systematic implementation of network integration strategies may contribute to improved work role performance in mental health care. PMID:28991923

Optimizing drilling performance using a selected drilling fluid

DOEpatents

Judzis, Arnis [Salt Lake City, UT; Black, Alan D [Coral Springs, FL; Green, Sidney J [Salt Lake City, UT; Robertson, Homer A [West Jordan, UT; Bland, Ronald G [Houston, TX; Curry, David Alexander [The Woodlands, TX; Ledgerwood, III, Leroy W.

2011-04-19

To improve drilling performance, a drilling fluid is selected based on one or more criteria and to have at least one target characteristic. Drilling equipment is used to drill a wellbore, and the selected drilling fluid is provided into the wellbore during drilling with the drilling equipment. The at least one target characteristic of the drilling fluid includes an ability of the drilling fluid to penetrate into formation cuttings during drilling to weaken the formation cuttings.

Improved, low cost inorganic-organic separators for rechargeable silver-zinc batteries

NASA Technical Reports Server (NTRS)

Sheibley, D. W.

1979-01-01

Several flexible, low-cost inorganic-organic separators with performance characteristics and cycle life equal to, or better than, the Lewis Research Center Astropower separator were developed. These new separators can be made on continuous-production equipment at about one-fourth the cost of the Astropower separator produced the same way. In test cells, these new separators demonstrate cycle life improvement, acceptable operating characteristics, and uniform current density. The various separator formulas, test cell construction, and data analysis are described.

The effects of higher strength and associated concrete properties on pavement performance

DOT National Transportation Integrated Search

2001-06-01

The major goal of this project was to develop recommendations for PCC properties and materials characteristics found in : higher strength JPCPs with improved long-term performance as determined by joint spalling and faulting, and transverse : slab...

The effects of higher strength and associated concrete properties on pavement performance.

DOT National Transportation Integrated Search

2001-06-01

The major goal of this project was to develop recommendations for PCC properties and materials characteristics found : in higher strength JPCP's with improved long-term performance as determined by joint spalling and faulting, and : transverse slab c...

Improving the environmental and performance characteristics of vehicles by introducing the surfactant additive into gasoline.

PubMed

Magaril, Elena; Magaril, Romen

2016-09-01

The operation of modern vehicles requires the introduction of package of fuel additives to ensure the required level of operating characteristics, some of which cannot be achieved by current oil refining methods. The use of additives allows flexibility of impact on the properties of the fuel at minimal cost, increasing the efficiency and environmental safety of vehicles. Among the wide assortment of additives available on the world market, many are surfactants. It has been shown that the introduction of some surfactants into gasoline concurrently reduces losses from gasoline evaporation, improves the mixture formation during injection of gasoline into the engine and improves detergent and anticorrosive properties. The surfactant gasoline additive that provides significant improvement in the quality of gasoline used and environmental and operating characteristics of vehicles has been developed and thoroughly investigated. The results of studies confirming the efficiency of the gasoline additive application are herein presented.

Timing of Occurrence Is the Most Important Characteristic of Spot Sign.

PubMed

Wang, Binli; Yan, Shenqiang; Xu, Mengjun; Zhang, Sheng; Liu, Keqin; Hu, Haitao; Selim, Magdy; Lou, Min

2016-05-01

Most previous studies have used single-phase computed tomographic angiography to detect the spot sign, a marker for hematoma expansion (HE) in spontaneous intracerebral hemorrhage. We investigated whether defining the spot sign based on timing on perfusion computed tomography (CTP) would improve its specificity for predicting HE. We prospectively enrolled supratentorial spontaneous intracerebral hemorrhage patients who underwent CTP within 6 hours of onset. Logistic regression was performed to assess the risk factors for HE and poor outcome. Predictive performance of individual CTP spot sign characteristics were examined with receiver operating characteristic analysis. Sixty-two men and 21 women with spontaneous intracerebral hemorrhage were included in this analysis. Spot sign was detected in 46% (38/83) of patients. Receiver operating characteristic analysis indicated that the timing of spot sign occurrence on CTP had the greatest area under receiver operating characteristic curve for HE (0.794; 95% confidence interval, 0.630-0.958; P=0.007); the cutoff time was 23.13 seconds. On multivariable analysis, the presence of early-occurring spot sign (ie, spot sign before 23.13 seconds) was an independent predictor not only of HE (odds ratio=28.835; 95% confidence interval, 6.960-119.458; P<0.001), but also of mortality at 3 months (odds ratio =22.377; 95% confidence interval, 1.773-282.334; P=0.016). Moreover, the predictive performance showed that the redefined early-occurring spot sign maintained a higher specificity for HE compared with spot sign (91% versus 74%). Redefining the spot sign based on timing of contrast leakage on CTP to determine early-occurring spot sign improves the specificity for predicting HE and 3-month mortality. The use of early-occurring spot sign could improve the selection of ICH patients for potential hemostatic therapy. © 2016 American Heart Association, Inc.

Performance characteristics of NuVal and the Overall Nutritional Quality Index (ONQI).

PubMed

Katz, David L; Njike, Valentine Y; Rhee, Lauren Q; Reingold, Arthur; Ayoob, Keith T

2010-04-01

Improving diets has considerable potential to improve health, but progress in this area has been limited, and advice to increase fruit and vegetable intake has largely gone unheeded. Our objective was to test the performance characteristics of the Overall Nutritional Quality Index (ONQI), a tool designed to help improve dietary patterns one well-informed choice at a time. The ONQI was developed by a multidisciplinary group of nutrition and public health scientists independent of food industry interests and is the basis for the NuVal Nutritional Guidance System. Dietary guidelines, existing nutritional scoring systems, and other pertinent scientific literature were reviewed. An algorithm incorporating >30 entries that represent both micro- and macronutrient properties of foods, as well as weighting coefficients representing epidemiologic associations between nutrients and health outcomes, was developed and subjected to consumer research and testing of performance characteristics. ONQI and expert panel rankings correlated highly (R = 0.92, P < 0.001). In consumer testing, approximately 80% of >800 study participants indicated that the ONQI would influence their purchase intent. ONQI scoring distinguished the more-healthful DASH (Dietary Approaches to Stop Hypertension) diet (mean score: 46) from the typical American diet according to the National Health and Nutrition Examination Survey (NHANES) 2003-2006 (mean score: 26.5; P < 0.01). In linear regression analysis of the NHANES 2003-2006 populations (n = 15,900), the NuVal system was significantly associated with the Healthy Eating Index 2005 (P < 0.0001). Recently generated data from ongoing studies indicate favorable effects on purchase patterns and significant correlation with health outcomes in large cohorts of men and women followed for decades. NuVal offers universally applicable nutrition guidance that is independent of food industry interests and is supported by consumer research and scientific evaluation of its performance characteristics.

Effects of resistance training on performance in previously trained endurance runners: A systematic review.

PubMed

Alcaraz-Ibañez, Manuel; Rodríguez-Pérez, Manuel

2018-03-01

The aim of this work was to identify, synthesize and evaluate the results of randomized controlled trials examining the effects of resistance training on performance indicators in previously trained endurance runners. A database search was carried out in PubMed, Science Direct, OvidSPMedLine, Wiley, Web of Science, ProQuest and Google Scholar. In accordance with the PRISMA checklist, 18 published articles dated prior to May 2016 involving 321 endurance runners were reviewed using the PEDro scale. Resistance training led to general improvements in muscular strength, running economy, muscle power factors, and direct performance in distances between 1,500 and 10,000 m. Such improvements were not accompanied by a significant increase in body mass or signs of overtraining. However, improvements did not occur in all cases, suggesting that they might depend on the specific characteristics of the resistance training applied. Although current evidence supports the effectiveness of resistance training to improve performance in already trained endurance runners, the methodological inconsistencies identified suggest that the results should be interpreted with caution. Future studies ought to investigate the benefits of resistance training in endurance runners while considering the existence of possible differentiated effects based on the specific characteristics of the resistance training carried out.

Experimental investigation of the cornering characteristics of 18 by 5.5, type 7, aircraft tires with different tread patterns

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Tanner, J. A.

1974-01-01

The characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 12 deg and at ground speeds from approximately 5 to 90 knots. The results indicate that a tread pattern with pinholes in the ribs reduces the tire cornering capability at high yaw angles on a damp surface but improves cornering on a dry surface. A tread pattern which has transverse grooves across the entire width of the tread improves the tire cornering performance slightly at high speeds on the flooded runway surface. The cornering capability of all the tires is degraded at high ground speeds by thin film lubrication and/or tire hydroplaning effects. Alterations to the conventional tread pattern provide only marginal improvements in the tire cornering capability which suggests that runway surface treatments may be a more effective way of improving aircraft ground performance during wet operations.

Performance Contracting and Quality Improvement in Outpatient Treatment: Effects on Waiting Time and Length of Stay

PubMed Central

Stewart, Maureen T.; Horgan, Constance M.; Garnick, Deborah W.; Ritter, Grant; McLellan, A. Thomas

2012-01-01

We evaluate effects of a performance contract (PC) implemented in Delaware in 2001 and participation in quality improvement (QI) programs on waiting time for treatment and length of stay (LOS) using client treatment episode level data from Delaware (n = 12,368) and Maryland (n = 147,151) for 1998 – 2006. Results of difference-in-difference analyses indicate waiting time declined 13 days following the PC, after controlling for client characteristics and historical trends. Participation in the PC and a formal QI program was associated with a decrease of 20 days. LOS increased 22 days under the PC and 24 days under the PC and QI programs, after controlling for client characteristics. The PC and QI program were associated with improvements in LOS and waiting time, although we cannot determine which aspects of the programs (incentives, training, monitoring) resulted in these changes. PMID:22445031

Aerodynamic performance investigation on waverider with variable blunt radius in hypersonic flows

NASA Astrophysics Data System (ADS)

Li, Shibin; Wang, Zhenguo; Huang, Wei; Xu, Shenren; Yan, Li

2017-08-01

Waverider is an important candidate for the design of hypersonic vehicles. However, the ideal waverider cannot be manufactured because of its sharp leading edge, so the leading edge should be blunted. In the paper, the HMB solver and laminar flow model have been utilized to obtain the flow field properties around the blunt waverider with the freestream Mach number being 8.0, and several novel strategies have been suggested to improve the aerodynamic performance of blunt waverider. The numerical method has been validated against experimental data, and the Stanton number(St) of the predicted result has been analyzed. The obtained results show good agreement with the experimental data. Stmax decreases by 58% and L/D decreases by 8.2% when the blunt radius increases from 0.0002 m to 0.001 m. ;Variable blunt waverider; is a good compromise for aerodynamic performance and thermal insulation. The aero-heating characteristics are very sensitive to Rmax. The position of the smallest blunt radius has a great effect on the aerodynamic performance. In addition, the type of blunt leading edge has a great effect on the aero-heating characteristics when Rmax is fixed. Therefore, out of several designs, Type 4is the best way to achieve the good overall performance. The ;Variable blunt waverider; not only improves the aerodynamic performance, but also makes the aero-heating become evenly-distributed, leading to better aero-heating characteristics.

Performance Rating Accuracy Improvement through Changes in Individual and System Characteristics.

ERIC Educational Resources Information Center

Kavanagh, Michael J.

Although the quest for better measurement of individual job performance has generated considerable empirical research in industrial and organizational psychology, the feeling persists that a good job is not really being done in measuring job performance. This research project investigated the effects of differences in both individual and systems…

Ta2O5 Polycrystalline Silicon Capacitors with CF4 Plasma Treatment

NASA Astrophysics Data System (ADS)

Kao, Chyuan-Haur; Chen, Hsiang

2012-04-01

In this research, the effects of CF4 plasma treatment with post annealing on the electrical characteristics and material properties of Ta2O5 dielectrics were determined. The dielectric performance characteristics of samples under different treatment conditions were measured using equivalent oxide thickness (EOT), current density-electric field (J-E) characteristics, gate voltage shift versus time, and Weibull plots. In addition, X-ray diffraction (XRD) analysis provided insight into the changes in crystalline structure, atomic force microscopy (AFM) measurements visualized the surface roughness, and secondary ion mass spectroscopy (SIMS) revealed the distribution of fluorine ions inside the dielectric samples. Findings indicate that dielectric performance can be significantly improved by CF4 plasma treatment for 1 min with post annealing at 800 °C. The improvements in electrical characteristics were caused by the appropriate incorporation of the fluorine atoms and the removal of the dangling bonds and traps. The Ta2O5 dielectric incorporated with appropriate CF4 plasma and annealing treatments shows great promise for future generation of nonvolatile memory applications.

Optimal control theory investigation of proprotor/wing response to vertical gust

NASA Technical Reports Server (NTRS)

Frick, J. K. D.; Johnson, W.

1974-01-01

Optimal control theory is used to design linear state variable feedback to improve the dynamic characteristics of a rotor and cantilever wing representing the tilting proprotor aircraft in cruise flight. The response to a vertical gust and system damping are used as criteria for the open and closed loop performance. The improvement in the dynamic characteristics achievable is examined for a gimballed rotor and for a hingeless rotor design. Several features of the design process are examined, including: (1) using only the wing or only the rotor dynamics in the control system design; (2) the use of a wing flap as well as the rotor controls for inputs; (3) and the performance of the system designed for one velocity at other forward speeds.

Drag Reduction and Performance Improvement of Hydraulic Torque Converters with Multiple Biological Characteristics.

PubMed

Chunbao, Liu; Li, Li; Yulong, Lei; Changsuo, Liu; Yubo, Zhang

2016-01-01

Fish-like, dolphin-like, and bionic nonsmooth surfaces were employed in a hydraulic torque converter to achieve drag reduction and performance improvement, which were aimed at reducing profile loss, impacting loss and friction loss, respectively. YJSW335, a twin turbine torque converter, was bionically designed delicately. The biological characteristics consisted of fish-like blades in all four wheels, dolphin-like structure in the first turbine and the stator, and nonsmooth surfaces in the pump. The prediction performance of bionic YJSW335, obtained by computational fluid dynamics simulation, was improved compared with that of the original model, and then it could be proved that drag reduction had been achieved. The mechanism accounting for drag reduction of three factors was also investigated. After bionic design, the torque ratio and the highest efficiencies of YJSW335 were both advanced, which were very difficult to achieve through traditional design method. Moreover, the highest efficiency of the low speed area and high speed area is 85.65% and 86.32%, respectively. By economic matching analysis of the original and bionic powertrains, the latter can significantly reduce the fuel consumption and improve the operating economy of the loader.

Drag Reduction and Performance Improvement of Hydraulic Torque Converters with Multiple Biological Characteristics

PubMed Central

Chunbao, Liu; Changsuo, Liu; Yubo, Zhang

2016-01-01

Fish-like, dolphin-like, and bionic nonsmooth surfaces were employed in a hydraulic torque converter to achieve drag reduction and performance improvement, which were aimed at reducing profile loss, impacting loss and friction loss, respectively. YJSW335, a twin turbine torque converter, was bionically designed delicately. The biological characteristics consisted of fish-like blades in all four wheels, dolphin-like structure in the first turbine and the stator, and nonsmooth surfaces in the pump. The prediction performance of bionic YJSW335, obtained by computational fluid dynamics simulation, was improved compared with that of the original model, and then it could be proved that drag reduction had been achieved. The mechanism accounting for drag reduction of three factors was also investigated. After bionic design, the torque ratio and the highest efficiencies of YJSW335 were both advanced, which were very difficult to achieve through traditional design method. Moreover, the highest efficiency of the low speed area and high speed area is 85.65% and 86.32%, respectively. By economic matching analysis of the original and bionic powertrains, the latter can significantly reduce the fuel consumption and improve the operating economy of the loader. PMID:27752220

Applying a social network analysis (SNA) approach to understanding radiologists' performance in reading mammograms

NASA Astrophysics Data System (ADS)

Tavakoli Taba, Seyedamir; Hossain, Liaquat; Heard, Robert; Brennan, Patrick; Lee, Warwick; Lewis, Sarah

2017-03-01

Rationale and objectives: Observer performance has been widely studied through examining the characteristics of individuals. Applying a systems perspective, while understanding of the system's output, requires a study of the interactions between observers. This research explains a mixed methods approach to applying a social network analysis (SNA), together with a more traditional approach of examining personal/ individual characteristics in understanding observer performance in mammography. Materials and Methods: Using social networks theories and measures in order to understand observer performance, we designed a social networks survey instrument for collecting personal and network data about observers involved in mammography performance studies. We present the results of a study by our group where 31 Australian breast radiologists originally reviewed 60 mammographic cases (comprising of 20 abnormal and 40 normal cases) and then completed an online questionnaire about their social networks and personal characteristics. A jackknife free response operating characteristic (JAFROC) method was used to measure performance of radiologists. JAFROC was tested against various personal and network measures to verify the theoretical model. Results: The results from this study suggest a strong association between social networks and observer performance for Australian radiologists. Network factors accounted for 48% of variance in observer performance, in comparison to 15.5% for the personal characteristics for this study group. Conclusion: This study suggest a strong new direction for research into improving observer performance. Future studies in observer performance should consider social networks' influence as part of their research paradigm, with equal or greater vigour than traditional constructs of personal characteristics.

Bionic Design, Materials and Performance of Bone Tissue Scaffolds

PubMed Central

Wu, Tong; Yu, Suihuai; Chen, Dengkai; Wang, Yanen

2017-01-01

Design, materials, and performance are important factors in the research of bone tissue scaffolds. This work briefly describes the bone scaffolds and their anatomic structure, as well as their biological and mechanical characteristics. Furthermore, we reviewed the characteristics of metal materials, inorganic materials, organic polymer materials, and composite materials. The importance of the bionic design in preoperative diagnosis models and customized bone scaffolds was also discussed, addressing both the bionic structure design (macro and micro structure) and the bionic performance design (mechanical performance and biological performance). Materials and performance are the two main problems in the development of customized bone scaffolds. Bionic design is an effective way to solve these problems, which could improve the clinical application of bone scaffolds, by creating a balance between mechanical performance and biological performance. PMID:29039749

Bionic Design, Materials and Performance of Bone Tissue Scaffolds.

PubMed

Wu, Tong; Yu, Suihuai; Chen, Dengkai; Wang, Yanen

2017-10-17

Design, materials, and performance are important factors in the research of bone tissue scaffolds. This work briefly describes the bone scaffolds and their anatomic structure, as well as their biological and mechanical characteristics. Furthermore, we reviewed the characteristics of metal materials, inorganic materials, organic polymer materials, and composite materials. The importance of the bionic design in preoperative diagnosis models and customized bone scaffolds was also discussed, addressing both the bionic structure design (macro and micro structure) and the bionic performance design (mechanical performance and biological performance). Materials and performance are the two main problems in the development of customized bone scaffolds. Bionic design is an effective way to solve these problems, which could improve the clinical application of bone scaffolds, by creating a balance between mechanical performance and biological performance.

Dual nozzle aerodynamic and cooling analysis study

NASA Technical Reports Server (NTRS)

Meagher, G. M.

1981-01-01

Analytical models to predict performance and operating characteristics of dual nozzle concepts were developed and improved. Aerodynamic models are available to define flow characteristics and bleed requirements for both the dual throat and dual expander concepts. Advanced analytical techniques were utilized to provide quantitative estimates of the bleed flow, boundary layer, and shock effects within dual nozzle engines. Thermal analyses were performed to define cooling requirements for baseline configurations, and special studies of unique dual nozzle cooling problems defined feasible means of achieving adequate cooling.

Job control and coworker support improve employee job performance.

PubMed

Nagami, Makiko; Tsutsumi, Akizumi; Tsuchiya, Masao; Morimoto, Kanehisa

2010-01-01

We examined the prospective association of psychosocial job characteristics with employee job performance among 777 full-time employees at a manufacturing company in Japan, using data from a one-year follow-up survey. Psychosocial job characteristics were measured by the Job Content Questionnaire in 2008; job performance was evaluated using the item from the World Mental Health Survey Instrument in 2008 and 2009. The association between psychosocial job characteristics and job performance was tested using multiple regression analysis, controlling for demographic variables, work status, average working hours per day, job type and job performance in 2008. Job control and coworker support in 2008 were positively related to job performance in 2009. Stratified analyses revealed that job control for staff and coworker support for managers were positively related to job performance in 2009. These associations were prominent among men; however, supervisor support in 2008 was negatively related to job performance in 2009 among men. Job demand was not significantly related to job performance. Our findings suggest that it is worthwhile to enhance employees' job control and provide a mutually supportive environment to ensure positive employee job performance.

Production, performance, slaughter characteristics, and meat quality of Ziwuling wild crossbred pigs.

PubMed

Chen, Guoshun; Sui, Yanan

2018-02-01

Wild boars, because of their large size and ability to survive adverse conditions, are usually used to cross with domestic breeds to improve the quality of domesticated pigs. This study aimed to investigate the growth performance, slaughter performance, and meat quality of Ziwuling crossbred pigs. Crossbred pigs in four groups (n = 8 per group, 4 boars and 4 sows, all aged 100 days), F 1 [wild × B (Bamei)], F 1  × B, F 1  × Y (Yorkshire), and F 1  × F 1 , were selected at a commercial pig farm. Growth performance, slaughter performance, and meat quality of these crossbred pigs were determined. Characteristics of fatty acids, amino acids, and longissimus muscle fiber in relation to growth, carcass, and meat quality traits were also investigated. Pigs in F 1 and F 1  × F 1 groups had lower average daily weight gain, water and storage loss rates, larger meat color score, higher muscle amino acid levels, larger muscle fiber diameter, and higher ratio of flavor amino acids to unsaturated fatty acids compared to other groups. Crossbred pigs with higher rate of wild boar's consanguinity could improve production performance, slaughter performance, and meat quality. Thus, crossbreeding wild pig with domestic breeds might be an effective method to improve meat quality and flavor.

Influence of feedback characteristics on perceived learning value of feedback in clerkships: does culture matter?

PubMed

Suhoyo, Yoyo; Van Hell, Elisabeth A; Kerdijk, Wouter; Emilia, Ova; Schönrock-Adema, Johanna; Kuks, Jan B M; Cohen-Schotanus, Janke

2017-04-05

Various feedback characteristics have been suggested to positively influence student learning. It is not clear how these feedback characteristics contribute to students' perceived learning value of feedback in cultures classified low on the cultural dimension of individualism and high on power distance. This study was conducted to validate the influence of five feedback characteristics on students' perceived learning value of feedback in an Indonesian clerkship context. We asked clerks in Neurology (n = 169) and Internal Medicine (n = 132) to assess on a 5-point Likert scale the learning value of the feedback they received. We asked them to record whether the feedback provider (1) informed the student what went well, (2) mentioned which aspects of performance needed improvement, (3) compared the student's performance to a standard, (4) further explained or demonstrated the correct performance, and (5) prepared an action plan with the student to improve performance. Data were analyzed using multilevel regression. A total of 250 students participated in this study, 131 from Internal Medicine (response rate 99%) and 119 from Neurology (response rate 70%). Of these participants, 225 respondents (44% males, 56% females) completed the form and reported 889 feedback moments. Students perceived feedback as more valuable when the feedback provider mentioned their weaknesses (β = 0.153, p < 0.01), compared their performance to a standard (β = 0.159, p < 0.01), explained or demonstrated the correct performance (β = 0.324, p < 0.001) and prepared an action plan with the student (β =0.496, p < 0.001). Appraisal of good performance did not influence the perceived learning value of feedback. No gender differences were found for perceived learning value. In Indonesia, we could validate four out of the five characteristics for effective feedback. We argue that our findings relate to culture, in particular to the levels of individualism and power distance. The recognized characteristics of what constitutes effective feedback should be validated across cultures.

Investigation of the Effect of Oil Modification on Critical Characteristics of Asphalt Binders

NASA Astrophysics Data System (ADS)

Golalipour, Amir

Thermally induced cracking of asphalt pavement continues to be a serious issue in cold climate regions as well as in areas which experience extreme daily temperature differentials. Low temperature cracking of asphalt pavements is attributed to thermal stresses and strains developed during cooling cycles. Improving asphalt binder low temperature fracture and stiffness properties continues to be a subject of particular concern. Therefore, significant amount of research has been focused on improving asphalt binder properties through modification. In recent years, wide ranges of oil based modifications have been introduced to improve asphalt binder performance, especially at the low service temperatures. Although, significant use of these oils is seen in practice, knowledge of the fundamental mechanisms of oil modification and their properties for achieving optimum characteristics is limited. Hence, this study focuses on better understanding of the effect of oil modifiers which would help better material selection and achieve optimum performance in terms of increasing the life span of pavements. In this study, the effect of oil modification on the rheological properties of the asphalt binder is investigated. To examine the effect of oil modification on binder characteristics, low temperature properties as well as high temperature performance of oil modified binders were evaluated. It is found that oils vary in their effects on asphalt binder performance. However, for all oils used in the study, adding an oil to binder can improve binder low temperature performance, and this result mainly attributed to the softening effect. In addition to that, a simple linear model is proposed to predict the performance grade of oil modified binder based on the properties of its constituents at high and low temperatures. Another part of this study focuses on the oil modification effect on asphalt binder thermal strain and stresses. A viscoelastic analytical procedure is combined with experimentally derived failure stress and strain envelopes to determine the controlling failure mechanism, strain tolerance or critical stress, in thermal cracking of oil modified binders. The low temperature failure results depict that oil modification has a good potential of improving the cracking resistance of asphalt binders during thermal cycles.

S.S.T.O. performance assessment with in-flight lox collection

NASA Astrophysics Data System (ADS)

Vandenkerckhove, J.; Czysz, P.

1995-10-01

Much attention has recently been given, up to harware development to in-flight oxygen collection as a means to improve considerably the performance of both TSTO & SSTO vehicles. A first assessment suggests that it permits simultaneously to improve much both gross take-off weight (by more than 30%) & dry weight (by more than 15%) of an SSTO and to lower significantly the Mach number of transition scramjet → rocket, from 15 down below 10, thereby reducing dramatically the programmatic development risks. After having compared in-flight lox collection with other SSTO concepts, this paper provides a tentative assessment of the performance of SSTO vehicles taking advantage of it, in particular their sensitivity to changes in system characteristics such as transition Mach number, vehicle slenderness (i.e. Küchemann's parameter τ) or planform loading at take-off and in collection characteristics, in particular collection ratio & specific collection plant weight.

High-Performance Polymers Having Low Melt Viscosities

NASA Technical Reports Server (NTRS)

Jensen, Brian J.

2005-01-01

High-performance polymers that have improved processing characteristics, and a method of making them, have been invented. One of the improved characteristics is low (relative to corresponding prior polymers) melt viscosities at given temperatures. This characteristic makes it possible to utilize such processes as resin-transfer molding and resin-film infusion and to perform autoclave processing at lower temperatures and/or pressures. Another improved characteristic is larger processing windows that is, longer times at low viscosities. Other improved characteristics include increased solubility of uncured polymer precursors that contain reactive groups, greater densities of cross-links in cured polymers, improved mechanical properties of the cured polymers, and greater resistance of the cured polymers to chemical attack. The invention is particularly applicable to poly(arylene ether)s [PAEs] and polyimides [PIs] that are useful as adhesives, matrices of composite materials, moldings, films, and coatings. PAEs and PIs synthesized according to the invention comprise mixtures of branched, linear, and star-shaped molecules. The monomers of these polymers can be capped with either reactive end groups to obtain thermosets or nonreactive end groups to obtain thermoplastics. The synthesis of a polymeric mixture according to the invention involves the use of a small amount of a trifunctional monomer. In the case of a PAE, the trifunctional monomer is a trihydroxy- containing compound for example, 1,3,5-trihydroxybenzene (THB). In the case of a PI, the trifunctional monomer is a triamine for example, triamino pyrimidine or melamine. In addition to the aforementioned trifunctional monomer, one uses the difunctional monomers of the conventional formulation of the polymer in question (see figure). In cases of nonreactive end caps, the polymeric mixtures of the invention have melt viscosities and melting temperatures lower than those of the corresponding linear polymers of equal molecular weights. The lower melting temperatures and melt viscosities provide larger processing windows. In cases of reactive end caps, the polymeric mixtures of the invention have lower melt viscosities before curing and the higher cross-link densities after curing (where branching in the uncured systems would become cross-links in the cured systems), relative to the corresponding linear polymers of equal molecular weights. The greater cross-link densities afford increased resistance to chemical attack and improved mechanical properties.

Influence of the association of the EVA and NBR on the characteristics of modified bitumen

NASA Astrophysics Data System (ADS)

Bensaada, A.; Soudani, K.; Haddadi, S.; Saoula, S.

2015-03-01

Durability and the performance of pavement depend mainly on the characteristics of materials which change over time like all other organic substances. They are subject to significant changes due to environmental conditions during the different phases of use. In the present work we investigated experimentally the influence of the association of ethyl vinyl acetate polymer (EVA) with an industrial waste, acrylonitrile-butadiene rubber (NBR) on the modification of bitumen AC 35-50 and its rheological behavior. The incorporation of NBR and EVA in the bitumen improved its intrinsic characteristics (softening point, penetration and ductility). In addition to improving the characteristics of bituminous binders that will affect the durability of bituminous structures, the environment will be preserved by the recycling of industrial waste.

Evaluation of hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program.

PubMed

Sheils, Catherine R; Dahlke, Allison R; Kreutzer, Lindsey; Bilimoria, Karl Y; Yang, Anthony D

2016-11-01

The American College of Surgeons National Surgical Quality Improvement Program is well recognized in surgical quality measurement and is used widely in research. Recent calls to make it a platform for national public reporting and pay-for-performance initiatives highlight the importance of understanding which types of hospitals elect to participate in the program. Our objective was to compare characteristics of hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program to characteristics of nonparticipating US hospitals. The 2013 American Hospital Association and Centers for Medicare & Medicaid Services Healthcare Cost Report Information System datasets were used to compare characteristics and operating margins of hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program to those of nonparticipating hospitals. Of 3,872 general medical and surgical hospitals performing inpatient surgery in the United States, 475 (12.3%) participated in the American College of Surgeons National Surgical Quality Improvement Program. Participating hospitals performed 29.0% of all operations in the United States. Compared with nonparticipating hospitals, American College of Surgeons National Surgical Quality Improvement Program hospitals had a higher mean annual inpatient surgical case volume (6,426 vs 1,874; P < .001) and a larger mean number of hospital beds (420 vs 167; P < .001); participating hospitals were more often teaching hospitals (35.2% vs 4.1%; P < .001), had more quality-related accreditations (P < .001), and had higher mean operating margins (P < .05). States with the highest proportions of hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program had established surgical quality improvement collaboratives. The American College of Surgeons National Surgical Quality Improvement Program hospitals are large teaching hospitals with more quality-related accreditations and financial resources. These findings should be considered when reviewing research studies using the American College of Surgeons National Surgical Quality Improvement Program data, and the findings reinforce that efforts are needed to facilitate participation in surgical quality improvement by all hospital types. Copyright © 2016 Elsevier Inc. All rights reserved.

Warrior Model for Human Performance and Injury Prevention: Eagle Tactical Athlete Program (ETAP) Part II.

PubMed

Sell, Timothy C; Abt, John P; Crawford, Kim; Lovalekar, Mita; Nagai, Takashi; Deluzio, Jennifer B; Smalley, Brain W; McGrail, Mark A; Rowe, Russell S; Cardin, Sylvain; Lephart, Scott M

2010-01-01

Physical training for United States military personnel requires a combination of injury prevention and performance optimization to counter unintentional musculoskeletal injuries and maximize warrior capabilities. Determining the most effective activities and tasks to meet these goals requires a systematic, research-based approach that is population specific based on the tasks and demands of the Warrior. The authors have modified the traditional approach to injury prevention to implement a comprehensive injury prevention and performance optimization research program with the 101st Airborne Division (Air Assault) at Fort Campbell, KY. This is second of two companion papers and presents the last three steps of the research model and includes Design and Validation of the Interventions, Program Integration and Implementation, and Monitor and Determine the Effectiveness of the Program. An 8-week trial was performed to validate the Eagle Tactical Athlete Program (ETAP) to improve modifiable suboptimal characteristics identified in Part I. The experimental group participated in ETAP under the direction of a ETAP Strength and Conditioning Specialist while the control group performed the current physical training at Fort Campbell under the direction of a Physical Training Leader and as governed by FM 21-20 for the 8-week study period. Soldiers performing ETAP demonstrated improvements in several tests for strength, flexibility, performance, physiology, and the APFT compared to current physical training performed at Fort Campbell. ETAP was proven valid to improve certain suboptimal characteristics within the 8-week trial as compared to the current training performed at Fort Campbell. ETAP has long-term implications and with expected greater improvements when implemented into a Division pre-deployment cycle of 10-12 months which will result in further systemic adaptations for each variable.

Performance tests of a two phase ejector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrell, G.S.; Kornhauser, A.A.

1995-12-31

The ejector expansion refrigeration cycle is a modified vapor compression cycle in which a two phase ejector is used to recover a portion of the work otherwise lost in the expansion valve. The ejector improves cycle performance by increasing compressor inlet pressure and by lowering the quality of liquid entering the evaporator. Theoretically, a cooling COP improvement of approximately 23% is achievable for a typical refrigerating cycle and an ideal ejector. If the ejector performed as well as typical single phase ejectors an improvement of 12% could be achieved. Previous tests have demonstrated a smaller 3.7% improvement; the difference ismore » in the poor performance of the two phase ejector. The purpose of this research is to understand the operating characteristics of the two phase ejector and to devise design improvements. A two phase ejector test rig has been constructed and tested. Preliminary data show performance superior to previously tested two phase ejectors, but still inferior to single phase ejectors. Ejector performance corresponds to refrigeration cycle COP improvements ranging from 3.9% to 7.6%.« less

Maintaining semen quality by improving cold chain equipment used in cattle artificial insemination

PubMed Central

Lieberman, Daniel; McClure, Elizabeth; Harston, Stephen; Madan, Damian

2016-01-01

Artificial insemination of dairy cattle is a common practice in the developing world that can improve farmer incomes and food security. Maintaining the fertilizing potential of frozen semen as it is manipulated, transported and stored is crucial to the success of this process. Here we describe simple technological improvements to protect semen from inadvertent thermal fluctuations that occur when users mishandle semen using standard equipment. We show that when frozen semen is mishandled, characteristics of semen biology associated with fertility are negatively affected. We describe several design modifications and results from thermal performance tests of several improved prototypes. Finally, we compare semen that has been mishandled in standard and improved equipment. The data suggest that our canister improvements can better maintain characteristics of semen biology that correlate with fertility when it is mishandled. PMID:27313137

Maintaining semen quality by improving cold chain equipment used in cattle artificial insemination.

PubMed

Lieberman, Daniel; McClure, Elizabeth; Harston, Stephen; Madan, Damian

2016-06-17

Artificial insemination of dairy cattle is a common practice in the developing world that can improve farmer incomes and food security. Maintaining the fertilizing potential of frozen semen as it is manipulated, transported and stored is crucial to the success of this process. Here we describe simple technological improvements to protect semen from inadvertent thermal fluctuations that occur when users mishandle semen using standard equipment. We show that when frozen semen is mishandled, characteristics of semen biology associated with fertility are negatively affected. We describe several design modifications and results from thermal performance tests of several improved prototypes. Finally, we compare semen that has been mishandled in standard and improved equipment. The data suggest that our canister improvements can better maintain characteristics of semen biology that correlate with fertility when it is mishandled.

Maintaining semen quality by improving cold chain equipment used in cattle artificial insemination

NASA Astrophysics Data System (ADS)

Lieberman, Daniel; McClure, Elizabeth; Harston, Stephen; Madan, Damian

2016-06-01

Artificial insemination of dairy cattle is a common practice in the developing world that can improve farmer incomes and food security. Maintaining the fertilizing potential of frozen semen as it is manipulated, transported and stored is crucial to the success of this process. Here we describe simple technological improvements to protect semen from inadvertent thermal fluctuations that occur when users mishandle semen using standard equipment. We show that when frozen semen is mishandled, characteristics of semen biology associated with fertility are negatively affected. We describe several design modifications and results from thermal performance tests of several improved prototypes. Finally, we compare semen that has been mishandled in standard and improved equipment. The data suggest that our canister improvements can better maintain characteristics of semen biology that correlate with fertility when it is mishandled.

Improved Steam Turbine Leakage Control with a Brush Seal Design

NASA Astrophysics Data System (ADS)

Turnquist, Norman; Chupp, Raymond E.; Pastrana, Ryan; Wolfe, Chris; Burnett, Mark

2002-10-01

This paper presents an improved steam turbine leakage control system with a brush seal design. The contents include: 1) Typical Design Characteristics; 2) Typical Brush Seal Locations; 3) Reduced Leakage Rates; 4) Performance Benefits; 5) System Considerations; 6) Rotor Dynamics; 7) Laboratory Tests and 8) Field Experience.

Enhancing performing characteristics of organic semiconducting films by improved solution processing

DOEpatents

Bazan, Guillermo C; Moses, Daniel; Peet, Jeffrey; Heeger, Alan J

2014-05-13

Improved processing methods for enhanced properties of conjugated polymer films are disclosed, as well as the enhanced conjugated polymer films produced thereby. Addition of low molecular weight alkyl-containing molecules to solutions used to form conjugated polymer films leads to improved photoconductivity and improvements in other electronic properties. The enhanced conjugated polymer films can be used in a variety of electronic devices, such as solar cells and photodiodes.

The Effect of Blunt-Trailing-Edge Modifications on the High-Speed Stability and Control Characteristics of a Swept-Wing Fighter Airplane

NASA Technical Reports Server (NTRS)

Sadoff, Melvin; Matteson, Frederick H.; Van Dyke, Rudolph D., Jr.

1954-01-01

An investigation was conducted on a 35 deg swept-wing fighter airplane to determine the effects of several blunt-trailing-edge modifications to the wing and tail on the high-speed stability and control characteristics and tracking performance. The results indicated significant improvement in the pitch-up characteristics for the blunt-aileron configuration at Mach numbers around 0.90. As a result of increased effectiveness of the blunt-trailing-edge aileron, the roll-off, customarily experienced with the unmodified airplane in wings-level flight between Mach numbers of about 0.9 and 1.0 was eliminated, The results also indicated that the increased effectiveness of the blunt aileron more than offset the large associated aileron hinge moment, resulting in significant improvement in the rolling performance at Mach numbers between 0.85 and 1.0. It appeared from these results that the tracking performance with the blunt-aileron configuration in the pitch-up and buffeting flight region at high Mach numbers was considerably improved over that of the unmodified airplane; however, the tracking errors of 8 to 15 mils were definitely unsatisfactory. A drag increment of about O.OOl5 due to the blunt ailerons was noted at Mach numbers to about 0.85. The drag increment was 0 at Mach numbers above 0.90.

Individual Characteristics and Unit Performance: A Review of Research and Methods

DTIC Science & Technology

1985-02-01

behavioral segments, improves performance. Simu- lation exercises , especially those employing new high-technology devices, provide surrogate...high-technology training simulation exercise MOB Military Occupational Specialty ORTT Operational Readiness Training Test-a field test REALTRAIN A...REAListic TRAINing simulation exercise SAM Surface-to-Air Missile SAT Scholastic Aptitude Test SQT Skill Qualification Test-an Army performance meas

Study on aerodynamics characteristics an urban concept car for energy-efficient race

NASA Astrophysics Data System (ADS)

Ambarita, H.; Siregar, M. R.; Kawai, H.

2018-03-01

"Horas Mesin USU" is a prototype of urban concept vehicle designed by University of Sumatera Utara to participate in the energy-efficient competition. This paper deals with a numerical study on aerodynamic characteristics of the Horas Mesin USU. The numerical analyses are carried out by solving the governing equations using CFD FLUENT commercial code. The turbulent flow is closed using k-epsilon turbulence model. In the results, pathline, velocity vector and pressure distribution are plotted. By using the pressure distributions, drag and lift coefficients are calculated. In order to make a comparison, the aerodynamic characteristics of the present design are compared with commercial city car Ford-Fiesta. The averaged drag coefficients of Horas Mesin USU and Ford-Fiesta are 0.24320 and 0.29598, respectively. On the other hand, the averaged lift coefficients of the Horas Mesin USU and Ford-Fiesta are 0.03192202 and 0.09485621, respectively. This fact suggests that Ford-Fiesta has a better aerodynamic performance in comparison with Horas Mesin USU. The flow field analysis shows that there are many modifications can be proposed to improve the aerodynamic performance of the Horas Mesin USU. It is suggested to perform further analysis to improve the aerodynamic performance of Horas Mesin USU.

Removal of natural organic matter by titanium tetrachloride: The effect of total hardness and ionic strength.

PubMed

Zhao, Y X; Shon, H K; Phuntsho, S; Gao, B Y

2014-02-15

This study is the first attempt to investigate the effect of total hardness and ionic strength on coagulation performance and the floc characteristics of titanium tetrachloride (TiCl4). Membrane fouling under different total hardness and ionic strength conditions was also evaluated during a coagulation-ultrafiltration (C-UF) hybrid process. Coagulation experiments were performed with two simulated waters, using humic acid (HA, high molecular weight) and fulvic acid (FA, relatively low molecular weight), respectively, as model natural organic matter (NOM). Results show that both particle and organic matter removal can be enhanced by increasing total hardness and ionic strength. Floc characteristics were significantly influenced by total hardness and ionic strength and were improved in terms of floc size, growth rate, strength, recoverability and compactness. The results of the UF tests show that the pre-coagulation with TiCl4 significantly improves the membrane permeate fluxes. Under different total hardness and ionic strength conditions, the membrane permeate flux varied according to both NOM and floc characteristics. The increase in total hardness and ionic strength improved the membrane permeate flux in the case of HA simulated water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improvement of thermal radiation characteristic of AC servomotor using Al-CNT composite material

NASA Astrophysics Data System (ADS)

Kikuchi, Y.; Wakiwaka, H.; Yanagihara, M.

2018-02-01

This study deals with a high thermal conductivity material of aluminum-carbon nanotube (CNT) composite with carbon fiber (CF) and the high radiation performance of AC servomotor using a stator made of nanotube composite material. The composite fabrication process was performed by melting a mixture of granular aluminum of less than 200 μm and CNT under conditions of pressed atmosphere at the same time. Two kinds of motors made using aluminum and the composite were evaluated to confirm the effect of thermal conductivity as the motor stator. A test rod of the composite with 14 wt% CF-7 wt% CNT-aluminum indicated the excellent thermal conductivity of 169 W/(mK) in the radial direction and 173 W/(mK) in the lengthwise direction. According to the obtained temperature radiation characteristic of the AC servomotor, the composite stator using CNT decreased the consumption energy to 16% compared to the conventional one. As a result, the highly efficient motor improved the radiation characteristic using the CNT composite stator.

Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system

NASA Astrophysics Data System (ADS)

Kong, Xiangdong; Ba, Kaixian; Yu, Bin; Cao, Yuan; Zhu, Qixin; Zhao, Hualong

2016-05-01

Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit (HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness.

Physician Perceptions of Performance Feedback in a Quality Improvement Activity.

PubMed

Eden, Aimee R; Hansen, Elizabeth; Hagen, Michael D; Peterson, Lars E

Physician performance and peer comparison feedback can affect physician care quality and patient outcomes. This study aimed to understand family physician perspectives of the value of performance feedback in quality improvement (QI) activities. This study analyzed American Board of Family Medicine open-ended survey data collected between 2004 and 2014 from physicians who completed a QI module that provided pre- and post-QI project individual performance data and peer comparisons. Physicians made 3480 comments in response to a question about this performance feedback, which were generally positive in nature (86%). Main themes that emerged were importance of accurate feedback data, enhanced detail in the content of feedback, and ability to customize peer comparison groups to compare performance to peers with similar patient populations or practice characteristics. Meaningful and tailored performance feedback may be an important tool for physicians to improve their care quality and should be considered an integral part of QI project design.

Impact of Time-of-Flight on PET Tumor Detection

PubMed Central

Kadrmas, Dan J.; Casey, Michael E.; Conti, Maurizio; Jakoby, Bjoern W.; Lois, Cristina; Townsend, David W.

2009-01-01

Time-of-flight (TOF) PET uses very fast detectors to improve localization of events along coincidence lines-of-response. This information is then utilized to improve the tomographic reconstruction. This work evaluates the effect of TOF upon an observer's performance for detecting and localizing focal warm lesions in noisy PET images. Methods An advanced anthropomorphic lesion-detection phantom was scanned 12 times over 3 days on a prototype TOF PET/CT scanner (Siemens Medical Solutions). The phantom was devised to mimic whole-body oncologic 18F-FDG PET imaging, and a number of spheric lesions (diameters 6–16 mm) were distributed throughout the phantom. The data were reconstructed with the baseline line-of-response ordered-subsets expectation-maximization algorithm, with the baseline algorithm plus point spread function model (PSF), baseline plus TOF, and with both PSF+TOF. The lesion-detection performance of each reconstruction was compared and ranked using localization receiver operating characteristics (LROC) analysis with both human and numeric observers. The phantom results were then subjectively compared to 2 illustrative patient scans reconstructed with PSF and with PSF+TOF. Results Inclusion of TOF information provides a significant improvement in the area under the LROC curve compared to the baseline algorithm without TOF data (P = 0.002), providing a degree of improvement similar to that obtained with the PSF model. Use of both PSF+TOF together provided a cumulative benefit in lesion-detection performance, significantly outperforming either PSF or TOF alone (P < 0.002). Example patient images reflected the same image characteristics that gave rise to improved performance in the phantom data. Conclusion Time-of-flight PET provides a significant improvement in observer performance for detecting focal warm lesions in a noisy background. These improvements in image quality can be expected to improve performance for the clinical tasks of detecting lesions and staging disease. Further study in a large clinical population is warranted to assess the benefit of TOF for various patient sizes and count levels, and to demonstrate effective performance in the clinical environment. PMID:19617317

Improvement of technical purpose materials performance characteristics with the radio frequency low pressure plasma

NASA Astrophysics Data System (ADS)

Makhotkina, L. Yu; Khristoliubova, V. I.

2017-11-01

The main aim of the work is to solve the actual problem of increasing the competitiveness of tanning products by reducing the prime cost and improving the quality of finished products due to the increased durability of the working elements of tanneries. The impact of the low pressure radio frequency (RF) plasma in the processes of treating for modification of the materials for special purposes is considered in the article. The results of working elements of tanneries and the materials for special purposes sample processing by a RF low pressure plasma are described. As a result of leather materials nano structuring and nano modifying physical, mechanical and hygienic characteristics were increased. Processing of the technical purpose materials allows to increase operational performance of products and extend their lifespan.

Rotor Hover Performance and Flowfield Measurements with Untwisted and Highly-Twisted Blades

NASA Technical Reports Server (NTRS)

Ramasamy, Manikandan; Gold, Nili P.; Bhagwat, Mahendra J.

2010-01-01

The flowfield and performance characteristics of highly-twisted blades were analyzed at various thrust conditions to improve the fundamental understanding relating the wake effects on rotor performance. Similar measurements made using untwisted blades served as the baseline case. Twisted blades are known to give better hover performance than untwisted blades at high thrust coefficients typical of those found in full-scale rotors. However, the present experiments were conducted at sufficiently low thrust (beginning from zero thrust), where the untwisted blades showed identical, if not better, performance when compared with the highly-twisted blades. The flowfield measurements showed some key wake differences between the two rotors, as well. These observations when combined with simple blade element momentum theory (also called annular disk momentum theory) helped further the understanding of rotor performance characteristics.

A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults.

PubMed

Agmon, Maayan; Belza, Basia; Nguyen, Huong Q; Logsdon, Rebecca G; Kelly, Valerie E

2014-01-01

Injury due to falls is a major problem among older adults. Decrements in dual-task postural control performance (simultaneously performing two tasks, at least one of which requires postural control) have been associated with an increased risk of falling. Evidence-based interventions that can be used in clinical or community settings to improve dual-task postural control may help to reduce this risk. THE AIMS OF THIS SYSTEMATIC REVIEW ARE: 1) to identify clinical or community-based interventions that improved dual-task postural control among older adults; and 2) to identify the key elements of those interventions. Studies were obtained from a search conducted through October 2013 of the following electronic databases: PubMed, CINAHL, PsycINFO, and Web of Science. Randomized and nonrandomized controlled studies examining the effects of interventions aimed at improving dual-task postural control among community-dwelling older adults were selected. All studies were evaluated based on methodological quality. Intervention characteristics including study purpose, study design, and sample size were identified, and effects of dual-task interventions on various postural control and cognitive outcomes were noted. Twenty-two studies fulfilled the selection criteria and were summarized in this review to identify characteristics of successful interventions. The ability to synthesize data was limited by the heterogeneity in participant characteristics, study designs, and outcome measures. Dual-task postural control can be modified by specific training. There was little evidence that single-task training transferred to dual-task postural control performance. Further investigation of dual-task training using standardized outcome measurements is needed.

Propulsive-lift concepts for improved low-speed performance of supersonic cruise arrow-wing configurations

NASA Technical Reports Server (NTRS)

Coe, P. L., Jr.

1976-01-01

Low-aspect-ratio highly swept arrow-wing supersonic aircraft possess high levels of aerodynamic efficiency at supersonic cruising speeds, however, their inherently poor low-speed lift characteristics require design constraints that compromise supersonic performance. The data discussed in this paper were obtained in wind tunnel tests with supersonic crusing configurations, in which propulsive-lift concepts were used to improve low-speed performance. The data show that the increased low-speed lift provided by propulsive-lift permits reduction of both wing size and installed thrust. This yields a batter engine/airframe match for improved supersonic cruise efficiency and range, while still providing acceptable take-off field lengths.

Hypersonic flight performance improvements by overfueled ramjet combustion

NASA Astrophysics Data System (ADS)

Sachs, G.; Bayer, R.; Lederer, R.; Schaber, R.

1991-12-01

The performance characteristics of hypersonic airbreathing engines are examined with emphasis on the effect of overfueled combustion on thrust and specific fuel-consumption, as well as on the combustion temperature, real gas effects, and pollution due to exhaust gas. It is shown that overfueled ramjet combustion can provide a means for improving flight performance at hypersonic speed and, consequently, reduce the mission fuel burn and the propulsion system weight. It is also shown that, in the separation flight maneuver, the separation condition for the upper stage can be improved by overfueled ramjet combustion of the first stage, making it possible to increase the payload which the upper stage can deliver into orbit. The flight mechanics modeling considerations are presented.

Performance enhancement of pentacene-based organic thin-film transistors using 6,13-pentacenequinone as a carrier injection interlayer

NASA Astrophysics Data System (ADS)

Fan, Ching-Lin; Lin, Wei-Chun; Chen, Hao-Wei

2018-06-01

This work demonstrates pentacene-based organic thin-film transistors (OTFTs) fabricated by inserting a 6,13-pentacenequinone (PQ) carrier injection layer between the source/drain (S/D) metal Au electrodes and pentacene channel layer. Compared to devices without a PQ layer, the performance characteristics including field-effect mobility, threshold voltage, and On/Off current ratio were significantly improved for the device with a 5-nm-thick PQ interlayer. These improvements are attributed to significant reduction of hole barrier height at the Au/pentacene channel interfaces. Therefore, it is believed that using PQ as the carrier injection layer is a good candidate to improve the pentacene-based OTFTs electrical performance.

Sleep to the beat: A nap favours consolidation of timing.

PubMed

Verweij, Ilse M; Onuki, Yoshiyuki; Van Someren, Eus J W; Van der Werf, Ysbrand D

2016-06-01

Growing evidence suggests that sleep is important for procedural learning, but few studies have investigated the effect of sleep on the temporal aspects of motor skill learning. We assessed the effect of a 90-min day-time nap on learning a motor timing task, using 2 adaptations of a serial interception sequence learning (SISL) task. Forty-two right-handed participants performed the task before and after a 90-min period of sleep or wake. Electroencephalography (EEG) was recorded throughout. The motor task consisted of a sequential spatial pattern and was performed according to 2 different timing conditions, that is, either following a sequential or a random temporal pattern. The increase in accuracy was compared between groups using a mixed linear regression model. Within the sleep group, performance improvement was modeled based on sleep characteristics, including spindle- and slow-wave density. The sleep group, but not the wake group, showed improvement in the random temporal, but especially and significantly more strongly in the sequential temporal condition. None of the sleep characteristics predicted improvement on either general of the timing conditions. In conclusion, a daytime nap improves performance on a timing task. We show that performance on the task with a sequential timing sequence benefits more from sleep than motor timing. More important, the temporal sequence did not benefit initial learning, because differences arose only after an offline period and specifically when this period contained sleep. Sleep appears to aid in the extraction of regularities for optimal subsequent performance. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Improving Spelling Performance and Spelling Consciousness

ERIC Educational Resources Information Center

Cordewener, Kim A. H.; Verhoeven, Ludo; Bosman, Anna M. T.

2016-01-01

This study examined the immediate and sustained effects of three training conditions on both spelling performance and spelling consciousness of 72 third-grade low- and high-skilled spellers. Spellers were assigned to a strategy-instruction, self-correction, or no-correction condition. The role of spelling ability and word characteristic were also…

Teacher Evaluation, Performance-Related Pay, and Constructivist Instruction

ERIC Educational Resources Information Center

Liang, Guodong; Akiba, Motoko

2015-01-01

Using statewide longitudinal teacher survey data collected in 2009 and 2010, this study examined the characteristics of teacher evaluation used to determine performance-related pay (PRP), and the association between PRP and improvement in the practice of constructivist instruction. The study found that 10.9% of middle school mathematics teachers…

Learning Molecular Structures in a Tangible Augmented Reality Environment

ERIC Educational Resources Information Center

Asai, Kikuo; Takase, Norio

2011-01-01

This article presents the characteristics of using a tangible table top environment produced by augmented reality (AR), aimed at improving the environment in which learners observe three-dimensional molecular structures. The authors perform two evaluation experiments. A performance test for a user interface demonstrates that learners with a…

Significant improvement in the electrical characteristics of Schottky barrier diodes on molecularly modified Gallium Nitride surfaces

NASA Astrophysics Data System (ADS)

Garg, Manjari; Naik, Tejas R.; Pathak, C. S.; Nagarajan, S.; Rao, V. Ramgopal; Singh, R.

2018-04-01

III-Nitride semiconductors face the issue of localized surface states, which causes fermi level pinning and large leakage current at the metal semiconductor interface, thereby degrading the device performance. In this work, we have demonstrated the use of a Self-Assembled Monolayer (SAM) of organic molecules to improve the electrical characteristics of Schottky barrier diodes (SBDs) on n-type Gallium Nitride (n-GaN) epitaxial films. The electrical characteristics of diodes were improved by adsorption of SAM of hydroxyl-phenyl metallated porphyrin organic molecules (Zn-TPPOH) onto the surface of n-GaN. SAM-semiconductor bonding via native oxide on the n-GaN surface was confirmed using X-ray photoelectron spectroscopy measurements. Surface morphology and surface electronic properties were characterized using atomic force microscopy and Kelvin probe force microscopy. Current-voltage characteristics of different metal (Cu, Ni) SBDs on bare n-GaN were compared with those of Cu/Zn-TPPOH/n-GaN and Ni/Zn-TPPOH/n-GaN SBDs. It was found that due to the molecular monolayer, the surface potential of n-GaN was decreased by ˜350 mV. This caused an increase in the Schottky barrier height of Cu and Ni SBDs from 1.13 eV to 1.38 eV and 1.07 eV to 1.22 eV, respectively. In addition to this, the reverse bias leakage current was reduced by 3-4 orders of magnitude for both Cu and Ni SBDs. Such a significant improvement in the electrical performance of the diodes can be very useful for better device functioning.

The high intensity solar cell: Key to low cost photovoltaic power

NASA Technical Reports Server (NTRS)

Sater, B. L.; Goradia, C.

1975-01-01

The design considerations and performance characteristics of the 'high intensity' (HI) solar cell are presented. A high intensity solar system was analyzed to determine its cost effectiveness and to assess the benefits of further improving HI cell efficiency. It is shown that residential sized systems can be produced at less than $1000/kW peak electric power. Due to their superior high intensity performance characteristics compared to the conventional and VMJ cells, HI cells and light concentrators may be the key to low cost photovoltaic power.

Quantifying Stove Emissions Related to Different Use Patterns for the Silver mini (Small Turkish) Space Heating Stove

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddalena, Randy; Lunden, Melissa; Wilson, Daniel

2012-08-01

Air pollution levels in Ulaanbaatar, Mongolia’s capital, are among the highest in the world. A primary source of this pollution is emissions from traditional coal - burning space heating stoves used in the Ger (tent) regions around Ulaanbaatar. Significant investment has been made to replace traditional heating stoves with improved low - emission high-efficiency stoves. Testing performed to support selection of replacement stoves or for optimizing performance may not be representative of true field performance of the improved stoves. Field observations and lab measurements indicate that performance is impacted , often adversely, by how stoves are actually being used inmore » the field. The objective of this project is to identify factors that influence stove emissions under typical field operating conditions and to quantify the impact of these factors. A highly - instrumented stove testing facility was constructed to allow for rapid and precise adjustment of factors influencing stove performance. Tests were performed using one of the improved stove models currently available in Ulaanbaatar. Complete burn cycles were conducted with Nailakh coal from the Ulaanbaatar region using various startup parameters, refueling conditions , and fuel characteristics . Measurements were collected simultaneously from undiluted chimney gas, diluted gas drawn directly from the chimney and plume gas collected from a dilution tunnel above the chimney. CO, CO 2, O 2, temperature, pressure, and particulate matter (PM) were measured . We found that both refueling events and coal characteristics strongly influenced PM emissions and stove performance. Start-up and refueling events lead to increased PM emissions with more than 98% of PM mass emitted during the 20% of the burn where coal ignition occurs. CO emissions are distributed more evenly over the burn cycle, peaking both during ignition and late in the burn cycle . We anticipate these results being useful for quantifying public health outcomes related to the distribution of improved stoves and to identify opportunities for improving and sustaining performance of the new stoves .« less

Multibeam satellite EIRP adaptability for aeronautical communications.

NASA Technical Reports Server (NTRS)

Kinal, G. V.; Bisaga, J. J.

1973-01-01

EIRP enhancement and management techniques, emphasizing aeronautical communications and adaptable multibeam concepts, are classified and characterized. User requirement and demand characteristics that exploit the improvement available from each technique are identified, and the relative performance improvement of each is discussed. It is concluded that aeronautical satellite communications could benefit greatly by the employment of these techniques.

Compounds and methods for improving plant performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unkefer, Pat J.; Knight, Thomas Joseph

2016-09-20

The invention is directed to methods and compositions for increasing a growth characteristic of a plant, increasing nutrient use efficiency of a plant, or improving a plant's ability to overcome stress comprising applying a composition comprising ketosuccinamate, a derivative thereof, or a salt thereof, to the plant or to a propagation material of the plant.

Electric field assisted sintering to improve the performance of nanostructured dye sensitized solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Shojaeifar, Mohsen; Mohajerani, Ezeddin; Fathollahi, Mohammadreza

2018-01-01

Herein, we report the application of electric field assisted sintering (EFAS) procedure in dye sensitized solar cells (DSSCs). The EFAS process improved DSSC performance by enhancing optical and electrical characteristics simultaneously. The EFAS procedure is shown to be capable of reducing the TiO2 nanoparticle aggregation leading to the higher surface area for dye molecules adsorbates. Lower nanoparticle aggregation can be evidently observed by field emission scanning electron microscopy imaging. By applying an external electric field, the current density and conversion efficiency improved significantly about 30% and 45%, respectively. UV-Visible spectra of the desorbed dye molecules on the porous nanoparticles bedding confirm a higher amount of dye loading in the presence of an external electric field. Correspondingly, comprehensive J-V characteristics modeling reveals the enhancement of the diffusion coefficient by EFAS process. The proposed method can be applied to improve the efficiency of the mesostructured hybrid perovskite solar cells, photodetectors, and quantum dot-sensitized solar cells, as well as reduction of the surface area loss in all porous media.

Improving The Performance of Customer Loyalty of Online Ticketing in Indonesia's Showbiz Industry

NASA Astrophysics Data System (ADS)

Dachyar, M.; Athory, E. S.

2015-06-01

Currently the entertainment industry is adopting online ticketing for supporting business from main products to profitability improvement. E-loyalty needs to be examined because are deals with less loyal customer characteristic. The sample are 249 customers whom have purchased for tickets online at least once. Data was gathered by questionnaires and analyzed by Path Analysis and Importance - Performance Analysis. The findings of the research indicate that satisfaction has the strongest relationship to e-loyalty. This study provides four improvement alternatives as a form of new business development strategy for showbiz industry in Indonesia.

Improved Adaptive LSB Steganography Based on Chaos and Genetic Algorithm

NASA Astrophysics Data System (ADS)

Yu, Lifang; Zhao, Yao; Ni, Rongrong; Li, Ting

2010-12-01

We propose a novel steganographic method in JPEG images with high performance. Firstly, we propose improved adaptive LSB steganography, which can achieve high capacity while preserving the first-order statistics. Secondly, in order to minimize visual degradation of the stego image, we shuffle bits-order of the message based on chaos whose parameters are selected by the genetic algorithm. Shuffling message's bits-order provides us with a new way to improve the performance of steganography. Experimental results show that our method outperforms classical steganographic methods in image quality, while preserving characteristics of histogram and providing high capacity.

Work Redesign and the Job Characteristics Model: A Longitudinal Field Study.

DTIC Science & Technology

1982-01-01

prior to and following work redesign. Their general job satisfaction , internal work motivation, job performance , conduct, and absenteeism, as well as...increase employee job satisfaction and internal work motivation and improve conduct and job performance , (2) the diagnostic phase is the most essential part...Strength on the Job Performance -Job Satisfaction Relationship . ....... . 117 Summary ....... .................. 119 4. RESEARCH METHODS

Rationalization and the Individuals with Disabilities Education Act: Exploring the Characteristics of Multi-Level Performance Monitoring and Improvement

ERIC Educational Resources Information Center

Mahu, Robert J.

2017-01-01

Performance measurement has emerged as a management tool that, accompanied by advances in technology and data analysis, has allowed public officials to control public policy at multiple levels of government. In the United States, the federal government has used performance measurement as part of an accountability strategy that enables Congress and…

Internal performance characteristics of thrust-vectored axisymmetric ejector nozzles

NASA Technical Reports Server (NTRS)

Lamb, Milton

1995-01-01

A series of thrust-vectored axisymmetric ejector nozzles were designed and experimentally tested for internal performance and pumping characteristics at the Langley research center. This study indicated that discontinuities in the performance occurred at low primary nozzle pressure ratios and that these discontinuities were mitigated by decreasing expansion area ratio. The addition of secondary flow increased the performance of the nozzles. The mid-to-high range of secondary flow provided the most overall improvements, and the greatest improvements were seen for the largest ejector area ratio. Thrust vectoring the ejector nozzles caused a reduction in performance and discharge coefficient. With or without secondary flow, the vectored ejector nozzles produced thrust vector angles that were equivalent to or greater than the geometric turning angle. With or without secondary flow, spacing ratio (ejector passage symmetry) had little effect on performance (gross thrust ratio), discharge coefficient, or thrust vector angle. For the unvectored ejectors, a small amount of secondary flow was sufficient to reduce the pressure levels on the shroud to provide cooling, but for the vectored ejector nozzles, a larger amount of secondary air was required to reduce the pressure levels to provide cooling.

The Relationship of Some Personality and Individual Characteristics with an Individual's Commitment to an Ideal Vision for Performance Improvement.

ERIC Educational Resources Information Center

Watkins, Ryan

2001-01-01

Examined the relationship among specified personality and individual characteristics of university students with their level of commitment to a measurable, results-focused statement of an ideal vision. Discusses locus of control, generativity, self-efficacy, values, and risk taking in the use of an ideal vision for strategic planning, needs…

Pooled effect of injection pressure and turbulence inducer piston on performance, combustion, and emission characteristics of a DI diesel engine powered with biodiesel blend.

PubMed

Isaac JoshuaRamesh Lalvani, J; Parthasarathy, M; Dhinesh, B; Annamalai, K

2016-12-01

In this study, the effect of injection pressure on combustion, performance, and emission characteristics of a diesel engine powered with turbulence inducer piston was studied. Engine tests were executed using conventional diesel and 20% blend of adelfa biodiesel [A20]. The results acquired from renewable fuel A20 in the conventional engine showed reduction in brake thermal efficiency being the result of poor air fuel mixing characteristics and the higher viscosity of the tested fuel. This prompted further research aiming at the improvement of turbulence for better air fuel mixing by a novel turbulence inducer piston [TIP]. The investigation was carried out to study the combined effect of injection pressure and turbulence inducer piston. Considerable improvement in the emission characteristics like hydrocarbon, carbon monoxide, smoke was acheived as a result of optimised injection pressure. Nevertheless, the nitrogen oxide emissions were slightly higher than those of the conventional unmodified engine. The engine with turbulence inducer piston shows the scope for reducing the major pollution and thus ensures environmental safety. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel double loop control model design for chemical unstable processes.

PubMed

Cong, Er-Ding; Hu, Ming-Hui; Tu, Shan-Tung; Xuan, Fu-Zhen; Shao, Hui-He

2014-03-01

In this manuscript, based on Smith predictor control scheme for unstable process in industry, an improved double loop control model is proposed for chemical unstable processes. Inner loop is to stabilize integrating the unstable process and transform the original process to first-order plus pure dead-time dynamic stable process. Outer loop is to enhance the performance of set point response. Disturbance controller is designed to enhance the performance of disturbance response. The improved control system is simple with exact physical meaning. The characteristic equation is easy to realize stabilization. Three controllers are separately design in the improved scheme. It is easy to design each controller and good control performance for the respective closed-loop transfer function separately. The robust stability of the proposed control scheme is analyzed. Finally, case studies illustrate that the improved method can give better system performance than existing design methods. © 2013 ISA Published by ISA All rights reserved.

Development of Independent-type Optical CT

NASA Astrophysics Data System (ADS)

Yamaguchi, Tatsushi; Shiozawa, Daigoro; Rokunohe, Toshiaki; Kida, Junzo; Zhang, Wei

Optical current transformers (optical CTs) have features that they can be made much smaller and lighter than conventional electromagnetic induction transformers by their simple structure, and contribute to improvement of equipment reliability because of their excellent surge resistance performance. Authors consider optical CTs to be next generation transformers, and are conducting research and development of optical CTs aiming to apply to measuring and protection in electric power systems. Specifically we developed an independent-type optical CT by utilizing basic data of optical CTs accumulated for large current characteristics, temperature characteristics, vibration resistance characteristics, and so on. In performance verification, type tests complying with IEC standards, such as short-time current tests, insulation tests, accuracy tests, and so on, showed good results. This report describes basic principle and configuration of optical CTs. After that, as basic characteristics of optical CTs, conditions and results of verification tests for dielectric breakdown characteristics of sensor fibers, large current characteristics, temperature characteristics, and vibration resistance characteristics are described. Finally, development outline of the independent-type optical CT aiming to apply to all digital substation and its type tests results are described.

Arcjet thruster research and technology

NASA Technical Reports Server (NTRS)

Makel, Darby B.; Cann, Gordon L.

1988-01-01

The design, analysis, and performance testing of an advanced lower power arcjet is described. A high impedance, vortex stabilized 1-kw class arcjet has been studied. A baseline research thruster has been built and endurance and performance tested. This advanced arcjet has demonstrated long lifetime characteristics, but lower than expected performance. Analysis of the specific design has identified modifications which should improve performance and maintain the long life time shown by the arcjet.

Propeller flow visualization techniques

NASA Technical Reports Server (NTRS)

Stefko, G. L.; Paulovich, F. J.; Greissing, J. P.; Walker, E. D.

1982-01-01

Propeller flow visualization techniques were tested. The actual operating blade shape as it determines the actual propeller performance and noise was established. The ability to photographically determine the advanced propeller blade tip deflections, local flow field conditions, and gain insight into aeroelastic instability is demonstrated. The analytical prediction methods which are being developed can be compared with experimental data. These comparisons contribute to the verification of these improved methods and give improved capability for designing future advanced propellers with enhanced performance and noise characteristics.

Physical performance characteristics of high-level female soccer players 12-21 years of age.

PubMed

Vescovi, J D; Rupf, R; Brown, T D; Marques, M C

2011-10-01

Performance assessment has become an invaluable component of monitoring player development and within talent identification programs in soccer, yet limited performance data are available for female soccer players across a wide age range. The aim of this study was to describe the physical performance characteristics of female soccer players ranging in age from 12 to 21 years. High-level female soccer players (n=414) were evaluated on linear sprinting (36.6 m with 9.1 m splits), countermovement jump (CMJ), and two agility tests. Separate one-way ANOVAs were used to compare performance characteristics between (1) each year of chronological age and (2) three age groups: 12-13 years, n=78, 14-17 years, n=223, and 18-21 years, n=113. Mean linear sprint speed over 9.1 m was similar across all chronological ages, however sprint speed over the final 9.1 m, CMJ height and agility scores improved until approximately 15-16 years. Outcomes from the group data indicated better performance on all tests for the 14-17-year-old group compared with the 12-13-year-old group. Additionally, sprint speed on the second and fourth 9.1 m splits and 36.6 m sprint speed as well as performance on the Illinois agility test was better in the 18-21-year-old group compared with the 14-17-year-old group. The findings from this study indicate that marked improvements of high intensity short duration work occur up until 15-16 years. Smaller gains in performance were observed beyond 16 years of age as evidenced by better performance on 36.6 m sprint speed, several sprint splits and the Illinois agility test in the college aged players (i.e., 18-21-year-old group). © 2010 John Wiley & Sons A/S.

Augmentation of maneuver performance by spanwise blowing

NASA Technical Reports Server (NTRS)

Erickson, G. E.; Campbell, J. F.

1977-01-01

A generalized wind tunnel model was tested to investigate new component concepts utilizing spanwise blowing to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on high angle of attack performance, stability, and control at subsonic speeds. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex-induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack. Spanwise blowing on the wing reduced horizontal tail loading and improved the lateral-directional stability characteristics of a wing-horizontal tail-vertical tail configuration.

Magnetostrictive materials and method for improving AC characteristics in same

DOEpatents

Pulvirenti, Patricia P.; Jiles, David C.

2001-08-14

The present invention provides Terfenol-D alloys ("doped" Terfenol) having optimized performances under the condition of time-dependent magnetic fields. In one embodiment, performance is optimized by lowering the conductivity of Terfenol, thereby improving the frequency response. This can be achieved through addition of Group III or IV elements, such as Si and Al. Addition of these types of elements provides scattering sites for conduction electrons, thereby increasing resistivity by 125% which leads to an average increase in penetration depth of 80% at 1 kHz and an increase in energy conversion efficiency of 55%. The permeability of doped Terfenol remains constant over a wider frequency range as compared with undoped Terfenol. These results demonstrate that adding impurities, such as Si and Al, are effective in improving the ac characteristics of Terfenol. A magnetoelastic Gruneisen parameter, .gamma..sub.me, has also been derived from the thermodynamic equations of state, and provides another means by which to characterize the coupling efficiency in magnetostrictive materials on a more fundamental basis.

Assessment of Institutional Capacities of Flood Management Institution in Pakistan

NASA Astrophysics Data System (ADS)

Khan, Noor M.

2009-03-01

Pakistan is frequently devastated by floods. The flood impacts can be reduced if the flood management institutional capacities are improved. This paper reviews and assesses the capacities of flood management institution in Pakistan. Citing a number of case studies about the flood management practices in Pakistan, the study estimates the weaknesses and strengths of the institution with respect to various phases of flood management, namely, mitigation, preparedness, response, and rehabilitation and also with respect to various characteristics of institutions, namely, deliberation, coordination, implementation, and evaluation, using an improved capacity assessment framework. It has been found that the performance of the mitigation and rehabilitation phases is not satisfactory and that of preparedness and response is satisfactory. It is concluded that the functions of deliberation need to be improved while the other three characteristics of institution namely, coordination, implementation, and evaluation are performing well. The study will help the policy makers to concentrate on the identified weak capacities.

Heat transfer enhancement in a lithium-ion cell through improved material-level thermal transport

NASA Astrophysics Data System (ADS)

Vishwakarma, Vivek; Waghela, Chirag; Wei, Zi; Prasher, Ravi; Nagpure, Shrikant C.; Li, Jianlin; Liu, Fuqiang; Daniel, Claus; Jain, Ankur

2015-12-01

While Li-ion cells offer excellent electrochemical performance for several applications including electric vehicles, they also exhibit poor thermal transport characteristics, resulting in reduced performance, overheating and thermal runaway. Inadequate heat removal from Li-ion cells originates from poor thermal conductivity within the cell. This paper identifies the rate-limiting material-level process that dominates overall thermal conduction in a Li-ion cell. Results indicate that thermal characteristics of a Li-ion cell are largely dominated by heat transfer across the cathode-separator interface rather than heat transfer through the materials themselves. This interfacial thermal resistance contributes around 88% of total thermal resistance in the cell. Measured value of interfacial resistance is close to that obtained from theoretical models that account for weak adhesion and large acoustic mismatch between cathode and separator. Further, to address this problem, an amine-based chemical bridging of the interface is carried out. This is shown to result in in four-times lower interfacial thermal resistance without deterioration in electrochemical performance, thereby increasing effective thermal conductivity by three-fold. This improvement is expected to reduce peak temperature rise during operation by 60%. By identifying and addressing the material-level root cause of poor thermal transport in Li-ion cells, this work may contributes towards improved thermal performance of Li-ion cells.

Thermocouples of tantalum and rhenium alloys for more stable vacuum-high temperature performance

NASA Technical Reports Server (NTRS)

Morris, J. F. (Inventor)

1977-01-01

Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising tantalum and rhenium and alloys containing only those two metals. The tantalum, rhenium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the tantalum, rhenium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.

Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners.

PubMed

Mikkola, Jussi; Vesterinen, Ville; Taipale, Ritva; Capostagno, Benoit; Häkkinen, Keijo; Nummela, Ari

2011-10-01

The purpose of this study was to assess the effects of heavy resistance, explosive resistance, and muscle endurance training on neuromuscular, endurance, and high-intensity running performance in recreational endurance runners. Twenty-seven male runners were divided into one of three groups: heavy resistance, explosive resistance or muscle endurance training. After 6 weeks of preparatory training, the groups underwent an 8-week resistance training programme as a supplement to endurance training. Before and after the 8-week training period, maximal strength (one-repetition maximum), electromyographic activity of the leg extensors, countermovement jump height, maximal speed in the maximal anaerobic running test, maximal endurance performance, maximal oxygen uptake ([V·]O(₂max)), and running economy were assessed. Maximal strength improved in the heavy (P = 0.034, effect size ES = 0.38) and explosive resistance training groups (P = 0.003, ES = 0.67) with increases in leg muscle activation (heavy: P = 0.032, ES = 0.38; explosive: P = 0.002, ES = 0.77). Only the heavy resistance training group improved maximal running speed in the maximal anaerobic running test (P = 0.012, ES = 0.52) and jump height (P = 0.006, ES = 0.59). Maximal endurance running performance was improved in all groups (heavy: P = 0.005, ES = 0.56; explosive: P = 0.034, ES = 0.39; muscle endurance: P = 0.001, ES = 0.94), with small though not statistically significant improvements in [V·]O(₂max) (heavy: ES = 0.08; explosive: ES = 0.29; muscle endurance: ES = 0.65) and running economy (ES in all groups < 0.08). All three modes of strength training used concurrently with endurance training were effective in improving treadmill running endurance performance. However, both heavy and explosive strength training were beneficial in improving neuromuscular characteristics, and heavy resistance training in particular contributed to improvements in high-intensity running characteristics. Thus, endurance runners should include heavy resistance training in their training programmes to enhance endurance performance, such as improving sprinting ability at the end of a race.

A DMAIC approach for process capability improvement an engine crankshaft manufacturing process

NASA Astrophysics Data System (ADS)

Sharma, G. V. S. S.; Rao, P. Srinivasa

2014-05-01

The define-measure-analyze-improve-control (DMAIC) approach is a five-strata approach, namely DMAIC. This approach is the scientific approach for reducing the deviations and improving the capability levels of the manufacturing processes. The present work elaborates on DMAIC approach applied in reducing the process variations of the stub-end-hole boring operation of the manufacture of crankshaft. This statistical process control study starts with selection of the critical-to-quality (CTQ) characteristic in the define stratum. The next stratum constitutes the collection of dimensional measurement data of the CTQ characteristic identified. This is followed by the analysis and improvement strata where the various quality control tools like Ishikawa diagram, physical mechanism analysis, failure modes effects analysis and analysis of variance are applied. Finally, the process monitoring charts are deployed at the workplace for regular monitoring and control of the concerned CTQ characteristic. By adopting DMAIC approach, standard deviation is reduced from 0.003 to 0.002. The process potential capability index ( C P) values improved from 1.29 to 2.02 and the process performance capability index ( C PK) values improved from 0.32 to 1.45, respectively.

Development efforts to improve curved-channel microchannel plates

NASA Technical Reports Server (NTRS)

Corbett, M. B.; Feller, W. B.; Laprade, B. N.; Cochran, R.; Bybee, R.; Danks, A.; Joseph, C.

1993-01-01

Curved-channel microchannel plate (C-plate) improvements resulting from an ongoing NASA STIS microchannel plate (MCP) development program are described. Performance limitations of previous C-plates led to a development program in support of the STIS MAMA UV photon counter, a second generation instrument on the Hubble Space Telescope. C-plate gain, quantum detection efficiency, dark noise, and imaging distortion, which are influenced by channel curvature non-uniformities, have all been improved through use of a new centrifuge fabrication technique. This technique will be described, along with efforts to improve older, more conventional shearing methods. Process optimization methods used to attain targeted C-plate performance goals will be briefly characterized. Newly developed diagnostic measurement techniques to study image distortion, gain uniformity, input bias angle, channel curvature, and ion feedback, will be described. Performance characteristics and initial test results of the improved C-plates will be reported. Future work and applications will also be discussed.

Altered spatiotemporal characteristics of gait in older adults with chronic low back pain.

PubMed

Hicks, Gregory E; Sions, J Megan; Coyle, Peter C; Pohlig, Ryan T

2017-06-01

Previous studies in older adults have identified that chronic low back pain (CLBP) is associated with slower gait speed. Given that slower gait speed is a predictor of greater morbidity and mortality among older adults, it is important to understand the underlying spatiotemporal characteristics of gait among older adults with CLBP. The purposes of this study were to determine (1) if there are differences in spatiotemporal parameters of gait between older adults with and without CLBP during self-selected and fast walking and (2) whether any of these gait characteristics are correlated with performance of a challenging walking task, e.g. stair negotiation. Spatiotemporal characteristics of gait were evaluated using a computerized walkway in 54 community-dwelling older adults with CLBP and 54 age- and sex-matched healthy controls. Older adults with CLBP walked slower than their pain-free peers during self-selected and fast walking. After controlling for body mass index and gait speed, step width was significantly greater in the CLBP group during the fast walking condition. Within the CLBP group, step width and double limb support time are significantly correlated with stair ascent/descent times. From a clinical perspective, these gait characteristics, which may be indicative of balance performance, may need to be addressed to improve overall gait speed, as well as stair-climbing performance. Future longitudinal studies confirming our findings are needed, as well as investigations focused on developing interventions to improve gait speed and decrease subsequent risk of mobility decline. Copyright © 2017 Elsevier B.V. All rights reserved.

Eutectic Contact Inks for Solar Cells

NASA Technical Reports Server (NTRS)

Ross, B.

1985-01-01

Low-resistance electrical contacts formed on solar cells by melting powders of eutectic composition of semiconductor and dopant. Process improves cell performance without subjecting cell to processing temperatures high enough to degrade other characteristics.

Evaluation of rubblization project in Ohio.

DOT National Transportation Integrated Search

2011-03-01

This study was initiated to systematically analyze the performance characteristics of ODOTs completed rubblization and roll (R/R) projects and to develop guidelines regarding improved specifications. : The study was conducted in three parts namely...

Physiological properties of brain-machine interface input signals.

PubMed

Slutzky, Marc W; Flint, Robert D

2017-08-01

Brain-machine interfaces (BMIs), also called brain-computer interfaces (BCIs), decode neural signals and use them to control some type of external device. Despite many experimental successes and terrific demonstrations in animals and humans, a high-performance, clinically viable device has not yet been developed for widespread usage. There are many factors that impact clinical viability and BMI performance. Arguably, the first of these is the selection of brain signals used to control BMIs. In this review, we summarize the physiological characteristics and performance-including movement-related information, longevity, and stability-of multiple types of input signals that have been used in invasive BMIs to date. These include intracortical spikes as well as field potentials obtained inside the cortex, at the surface of the cortex (electrocorticography), and at the surface of the dura mater (epidural signals). We also discuss the potential for future enhancements in input signal performance, both by improving hardware and by leveraging the knowledge of the physiological characteristics of these signals to improve decoding and stability. Copyright © 2017 the American Physiological Society.

Comparison of display enhancement with intelligent decision-aiding

NASA Technical Reports Server (NTRS)

Kirlik, Alex; Markert, Wendy J.; Kossack, Merrick

1992-01-01

Currently, two main approaches exist for improving the human-machine interface component of a system in order to improve overall system performance, display enhancement and intelligent decision aiding. Each of these two approaches has its own set of advantages and disadvantages, as well as introduce its own set of additional performance problems. These characteristics should help identify which types of problem situations and domains are better aided by which type of strategy. The characteristic issues are described of these two decision aiding strategies. Then differences in expert and novice decision making are described in order to help determine whether a particular strategy may be better for a particular type of user. Finally, research is outlined to compare and contrast the two technologies, as well as to examine the interaction effects introduced by the different skill levels and the different methods for training operators.

The Effects of Compensatory Scanning Training on Mobility in Patients with Homonymous Visual Field Defects: Further Support, Predictive Variables and Follow-Up

PubMed Central

Melis-Dankers, Bart J. M.; Brouwer, Wiebo H.; Tucha, Oliver; Heutink, Joost

2016-01-01

Introduction People with homonymous visual field defects (HVFD) often report difficulty detecting obstacles in the periphery on their blind side in time when moving around. Recently, a randomized controlled trial showed that the InSight-Hemianopia Compensatory Scanning Training (IH-CST) specifically improved detection of peripheral stimuli and avoiding obstacles when moving around, especially in dual task situations. Method The within-group training effects of the previously reported IH-CST are examined in an extended patient group. Performance of patients with HVFD on a pre-assessment, post-assessment and follow-up assessment and performance of a healthy control group are compared. Furthermore, it is examined whether training effects can be predicted by demographic characteristics, variables related to the visual disorder, and neuropsychological test results. Results Performance on both subjective and objective measures of mobility-related scanning was improved after training, while no evidence was found for improvement in visual functions (including visual fields), reading, visual search and dot counting. Self-reported improvement did not correlate with improvement in objective mobility performance. According to the participants, the positive effects were still present six to ten months after training. No demographic characteristics, variables related to the visual disorder, and neuropsychological test results were found to predict the size of training effect, although some inconclusive evidence was found for more improvement in patients with left-sided HVFD than in patients with right-sided HFVD. Conclusion Further support was found for a positive effect of IH-CST on detection of visual stimuli during mobility-related activities specifically. Based on the reports given by patients, these effects appear to be long-term effects. However, no conclusions can be drawn on the objective long-term training effects. PMID:27935973

Relationship between performance variables and baseball ability in youth baseball players.

PubMed

Nakata, Hiroki; Nagami, Tomoyuki; Higuchi, Takatoshi; Sakamoto, Kiwako; Kanosue, Kazuyuki

2013-10-01

The present study investigated the relationship of performance variables and anthropometric measurements on baseball ability in 164 youth baseball players (age: 6.4-15.7 years). To evaluate their baseball performance, ball speeds in pitching and batting were recorded and kinetic energies of the pitched and hit balls were calculated. To record anthropometric and physical fitness characteristics, height and weight were measured and a battery of physical fitness tests covering standing long jump, side steps, sit-ups, 10-m sprint, trunk flexion, back strength, and grip strengths of both hands were conducted. The results of a multiple regression analysis revealed several significant predictors: age, body mass index (BMI), standing long jump, 10-m sprint, and grip strength for pitched ball kinetic energy and age, BMI, standing long jump, and back strength for hit ball kinetic energy. This study provides scientific evidence that relates certain specific physical performance tests and body characteristics with high achievement in the actual performance of pitching and batting. Youth players, their parents, coaches, and trainers would benefit by addressing these characteristics when planning training programs to improve the baseball performance of youth players.

A cross-cultural study of organizational factors on safety: Japanese vs. Taiwanese oil refinery plants.

PubMed

Hsu, Shang Hwa; Lee, Chun-Chia; Wu, Muh-Cherng; Takano, Kenichi

2008-01-01

This study attempts to identify idiosyncrasies of organizational factors on safety and their influence mechanisms in Taiwan and Japan. Data were collected from employees of Taiwanese and Japanese oil refinery plants. Results show that organizational factors on safety differ in the two countries. Organizational characteristics in Taiwanese plants are highlighted as: higher level of management commitment to safety, harmonious interpersonal relationship, more emphasis on safety activities, higher devotion to supervision, and higher safety self-efficacy, as well as high quality of safety performance. Organizational characteristics in Japanese plants are highlighted as: higher level of employee empowerment and attitude towards continuous improvement, more emphasis on systematic safety management approach, efficient reporting system and teamwork, and high quality of safety performance. The casual relationships between organizational factors and workers' safety performance were investigated using structural equation modeling (SEM). Results indicate that the influence mechanisms of organizational factors in Taiwan and Japan are different. These findings provide insights into areas of safety improvement in emerging countries and developed countries respectively.

Comparing hospital costs: what is gained by accounting for more than a case-mix index?

PubMed

Hvenegaard, Anne; Street, Andrew; Sørensen, Torben Højmark; Gyrd-Hansen, Dorte

2009-08-01

We explore what effect controlling for various patient characteristics beyond a case-mix index (DRG) has on inferences drawn about the relative cost performance of hospital departments. We estimate fixed effect cost models in which 3754 patients are clustered within six Danish vascular departments. We compare a basic model including a DRG index only with models also including age and gender, health related characteristics, such as smoking status, diabetes, and American Society of Anesthesiogists score (ASA-score), and socioeconomic characteristics such as income, employment and whether the patient lives alone. We find that the DRG index is a robust and important explanatory factor and adding other routinely collected characteristics such as age and gender and other health related or socioeconomic characteristics do not seem to alter the results significantly. The results are more sensitive to choice of functional form, i.e. in particular to whether costs are log transformed. Our results suggest that the routinely collected characteristics such as DRG index, age and gender are sufficient when drawing inferences about relative cost performance. Adding health related or socioeconomic patient characteristics only slightly improves our model in terms of explanatory power but not when drawing inferences about relative performance. The results are, however, sensitive to whether costs are log transformed.

CF6 jet engine performance improvement: High pressure turbine roundness

NASA Technical Reports Server (NTRS)

Howard, W. D.; Fasching, W. A.

1982-01-01

An improved high pressure turbine stator reducing fuel consumption in current CF6-50 turbofan engines was developed. The feasibility of the roundness and clearance response improvements was demonstrated. Application of these improvements will result in a cruise SFC reduction of 0.22 percent for new engines. For high time engines, the improved roundness and response characteristics results in an 0.5 percent reduction in cruise SFC. A basic life capability of the improved HP turbine stator in over 800 simulated flight cycles without any sign of significant distress is shown.

Atmospheric cloud physics thermal systems analysis

NASA Technical Reports Server (NTRS)

1977-01-01

Engineering analyses performed on the Atmospheric Cloud Physics (ACPL) Science Simulator expansion chamber and associated thermal control/conditioning system are reported. Analyses were made to develop a verified thermal model and to perform parametric thermal investigations to evaluate systems performance characteristics. Thermal network representations of solid components and the complete fluid conditioning system were solved simultaneously using the Systems Improved Numerical Differencing Analyzer (SINDA) computer program.

Analytical study of effect of casing treatment on performance of a multistage compressor

NASA Technical Reports Server (NTRS)

Snyder, R. W.; Blade, R. J.

1972-01-01

The simulation was based on individual stage pressure and efficiency maps. These maps were modified to account for casing treatment effects on the individual stage characteristics. The individual stage maps effects on overall compressor performance were observed. The results show that to improve the performance of the compressor in its normal operating range, casing treatment of the rear stages is required.

Recent improvements in catfish hatcheries not only changed the type of catfish to be raised but also how they are raised

USDA-ARS?s Scientific Manuscript database

Disease, low survival, and increased feed costs coupled with an influx of cheap foreign catfish declined the US farm-raised catfish production by over 50% in the last decade. Farm efficiency can be improved by development and use of catfish with enhanced performance characteristics. Hybrid catfish ...

Advanced missile technology. A review of technology improvement areas for cruise missiles. [including missile design, missile configurations, and aerodynamic characteristics

NASA Technical Reports Server (NTRS)

Cronvich, L. L.; Liepman, H. P.

1979-01-01

Technology assessments in the areas of aerodynamics, propulsion, and structures and materials for cruise missile systems are discussed. The cruise missiles considered cover the full speed, altitude, and target range. The penetrativity, range, and maneuverability of the cruise missiles are examined and evaluated for performance improvements.

Characteristic of a Digital Correlation Radiometer Back End with Finite Wordlength

NASA Technical Reports Server (NTRS)

Biswas, Sayak K.; Hyde, David W.; James, Mark W.; Cecil, Daniel J.

2017-01-01

The performance characteristic of a digital correlation radiometer signal processing back end (DBE) is analyzed using a simulator. The particular design studied here corresponds to the airborne Hurricane Imaging radiometer which was jointly developed by the NASA Marshall Space Flight Center, University of Michigan, University of Central Florida and NOAA. Laboratory and flight test data is found to be in accord with the simulation results. Overall design seems to be optimum for the typical input signal dynamic range. It was found that the performance of the digital kurtosis could be improved by lowering the DBE input power level. An unusual scaling between digital correlation channels observed in the instrument data is confirmed to be a DBE characteristic.

Grading technologies for the manufacture of innovative cutting blades

NASA Astrophysics Data System (ADS)

Rostek, Tim; Homberg, Werner

2018-05-01

Cutting blades for harvesting applications are used in a variety of agricultural machines. These parts are in contact with highly abrasive lawn clippings and often wear out within hours which results in high expensive re-sharpening maintenance. This paper relates to manufacturing techniques enhancing the durability of cutting blades based on a structural analysis of the prevailing wear mechanisms containing chipping and abrasive wear. Each mechanism results in specific demands on the cutting edge's mechanical characteristics. The design of evaluation methods respectively is one issue of the paper. This is basis for approaches to improve the cutting edge performance on purpose. On option to improve abrasive wear resistance and, thus, service life is the application of locally graded steel materials as semi-finished products for self-sharpening cutting blades. These materials comprise a layered structure consisting of a hard, wear resistant layer and a relatively softer layer which is lesser wear resistant. As the cutting blade is subjected to wear conditions, the less wear resistant layer wears faster than the relatively more wear resistant harder layer revealing a durable cross section of the cutting edge and, thus, cutting performance. Anyways, chipping is another key issue on the cutting edge's lifetime. Here, the cutting edges cross section by means of geometry and grind respectively as well as its mechanical properties matter. FEM analysis reveal innovative options to optimize the cross section of the blade as well as thermomechanical strengthening add further strength to reduce chipping. This paper contains a comprehensive strategy to improve cutting blades with use of innovative manufacturing technologies which apply application-specific graded mechanical characteristics and, thus, significantly improved performance characteristics.

A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults

PubMed Central

Agmon, Maayan; Belza, Basia; Nguyen, Huong Q; Logsdon, Rebecca G; Kelly, Valerie E

2014-01-01

Background Injury due to falls is a major problem among older adults. Decrements in dual-task postural control performance (simultaneously performing two tasks, at least one of which requires postural control) have been associated with an increased risk of falling. Evidence-based interventions that can be used in clinical or community settings to improve dual-task postural control may help to reduce this risk. Purpose The aims of this systematic review are: 1) to identify clinical or community-based interventions that improved dual-task postural control among older adults; and 2) to identify the key elements of those interventions. Data sources Studies were obtained from a search conducted through October 2013 of the following electronic databases: PubMed, CINAHL, PsycINFO, and Web of Science. Study selection Randomized and nonrandomized controlled studies examining the effects of interventions aimed at improving dual-task postural control among community-dwelling older adults were selected. Data extraction All studies were evaluated based on methodological quality. Intervention characteristics including study purpose, study design, and sample size were identified, and effects of dual-task interventions on various postural control and cognitive outcomes were noted. Data synthesis Twenty-two studies fulfilled the selection criteria and were summarized in this review to identify characteristics of successful interventions. Limitations The ability to synthesize data was limited by the heterogeneity in participant characteristics, study designs, and outcome measures. Conclusion Dual-task postural control can be modified by specific training. There was little evidence that single-task training transferred to dual-task postural control performance. Further investigation of dual-task training using standardized outcome measurements is needed. PMID:24741296

The effects of magnetic field in plume region on the performance of multi-cusped field thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Peng, E-mail: hupengemail@126.com; Liu, Hui, E-mail: thruster@126.com; Yu, Daren

2015-10-15

The performance characteristics of a Multi-cusped Field Thruster depending on the magnetic field in the plume region were investigated. Five magnetic field shielding rings were separately mounted near the exit of discharge channel to decrease the strength of magnetic field in the plume region in different levels, while the magnetic field in the upstream was well maintained. The test results show that the electron current increases with the decrease of magnetic field strength in the plume region, which gives rise to higher propellant utilization and lower current utilization. On the other hand, the stronger magnetic field in the plume regionmore » improves the performance at low voltages (high current mode) while lower magnetic field improves the performance at high voltages (low current mode). This work can provide some optimal design ideas of the magnetic strength in the plume region to improve the performance of thruster.« less

An experimental and theoretical analysis of the aerodynamic characteristics of a biplane-winglet configuration. M.D. Thesis

NASA Technical Reports Server (NTRS)

Gall, P. D.

1984-01-01

Improving the aerodynamic characteristics of an airplane with respect to maximizing lift and minimizing induced and parasite drag are of primary importance in designing lighter, faster, and more efficient aircraft. Previous research has shown that a properly designed biplane wing system can perform superiorly to an equivalent monoplane system with regard to maximizing the lift-to-drag ratio and efficiency factor. Biplanes offer several potential advantages over equivalent monoplanes, such as a 60-percent reduction in weight, greater structural integrity, and increased roll response. The purpose of this research is to examine, both theoretically and experimentally, the possibility of further improving the aerodynamic characteristics of the biplanes configuration by adding winglets. Theoretical predictions were carried out utilizing vortex-lattice theory, which is a numerical method based on potential flow theory. Experimental data were obtained by testing a model in the Pennsylvania State University's subsonic wind tunnel at a Reynolds number of 510,000. The results showed that the addition of winglets improved the performance of the biplane with respect to increasing the lift-curve slope, increasing the maximum lift coefficient, increasing the efficiency factor, and decreasing the induced drag. A listing of the program is included in the Appendix.

Task and work performance on Skylab missions 2, 3, and 4: Time and motion study: Experiment M151

NASA Technical Reports Server (NTRS)

Kubis, J. F.; Mclaughlin, E. J.; Jackson, J. M.; Rusnak, R.; Mcbride, G. H.; Saxon, S. V.

1977-01-01

Human task performance was evaluated under weightlessness conditions during long duration space flight in order to study the characteristics of the adaptation function. Results show that despite pronounced variability in training schedules and in initial reaction to the Skylab environment, in-flight task performance was relatively equivalent among Skylab crews, and behavioral performance continued to improve from beginning to end of all missions.

Aluminum anode for aluminum-air battery - Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution

NASA Astrophysics Data System (ADS)

Park, In-Jun; Choi, Seok-Ryul; Kim, Jung-Gu

2017-07-01

Effects of Zn and In additions on the aluminum anode for Al-air battery in alkaline solution are examined by the self-corrosion rate, cell voltage, current-voltage characteristics, anodic polarization, discharge performance and AC impedance measurements. The passivation behavior of Zn-added anode during anodic polarization decreases the discharge performance of Al-air battery. The addition of In to Al-Zn anode reduces the formation of Zn passivation film by repeated adsorption and desorption behavior of In ion onto anode surface. The attenuated Zn passive layer by In ion attack leads to the improvement of discharge performance of Al-air battery.

Point matching: A new electronic method for homogenizing the phase characteristics of giant magnetoimpedance sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, E. Costa, E-mail: edusilva@ele.puc-rio.br; Gusmão, L. A. P.; Barbosa, C. R. Hall

2014-08-15

Recently, our research group at PUC-Rio discovered that magnetic transducers based on the impedance phase characteristics of GMI sensors have the potential to multiply by one hundred the sensitivity values when compared to magnitude-based GMI transducers. Those GMI sensors can be employed in the measurement of ultra-weak magnetic fields, which intensities are even lower than the environmental magnetic noise. A traditional solution for cancelling the electromagnetic noise and interference makes use of gradiometric configurations, but the performance is strongly tied to the homogeneity of the sensing elements. This paper presents a new method that uses electronic circuits to modify themore » equivalent impedance of the GMI samples, aiming at homogenizing their phase characteristics and, consequently, improving the performance of gradiometric configurations based on GMI samples. It is also shown a performance comparison between this new method and another homogenization method previously developed.« less

Effects of nutrition level of concentrate-based diets on growth performance and carcass characteristics of Hainan black goats.

PubMed

Wang, Dingfa; Zhou, Luli; Zhou, Hanlin; Hou, Guanyu; Li, Mao; Shi, Liguang; Huang, Xianzhou; Guan, Song

2014-06-01

This study assessed the effects of different nutrition levels of diets on growth performance and carcass characteristics of Hainan black goat. Twenty-four goats were divided into six diet treatments, which consisted of two levels of crude protein (CP; 15 and 17 %) and three levels of digestive energy (DE; 11.72, 12.55, and 13.39 MJ/kg). The results revealed that 17 % CP significantly (P < 0.05) increased ADG and improved FCR compared with 15 % CP. Therefore, the CP levels of diet affected growth performance. CP and DE levels in the diet had no significant effects (P > 0.05) on carcass characteristics of the goats. The mRNA expression levels of insulin-like growth factor 1 in muscle tissues increased with increasing CP and DE levels (P < 0.05).

Computer controlled performance mapping of thermionic converters: effect of collector, guard-ring potential imbalances on the observed collector current-density, voltage characteristics and limited range performance map of an etched-rhenium, niobium planar converter

NASA Technical Reports Server (NTRS)

Manista, E. J.

1972-01-01

The effect of collector, guard-ring potential imbalance on the observed collector-current-density J, collector-to-emitter voltage V characteristic was evaluated in a planar, fixed-space, guard-ringed thermionic converter. The J,V characteristic was swept in a period of 15 msec by a variable load. A computerized data acquisition system recorded test parameters. The results indicate minimal distortion of the J,V curve in the power output quadrant for the nominal guard-ring circuit configuration. Considerable distortion, along with a lowering of the ignited-mode striking voltage, was observed for the configuration with the emitter shorted to the guard ring. A limited-range performance map of an etched-rhenium, niobium, planar converter was obtained by using an improved computer program for the data acquisition system.

Performance Variability as a Predictor of Response to Aphasia Treatment.

PubMed

Duncan, E Susan; Schmah, Tanya; Small, Steven L

2016-10-01

Performance variability in individuals with aphasia is typically regarded as a nuisance factor complicating assessment and treatment. We present the alternative hypothesis that intraindividual variability represents a fundamental characteristic of an individual's functioning and an important biomarker for therapeutic selection and prognosis. A total of 19 individuals with chronic aphasia participated in a 6-week trial of imitation-based speech therapy. We assessed improvement both on overall language functioning and repetition ability. Furthermore, we determined which pretreatment variables best predicted improvement on the repetition test. Significant gains were made on the Western Aphasia Battery-Revised (WAB) Aphasia Quotient, Cortical Quotient, and 2 subtests as well as on a separate repetition test. Using stepwise regression, we found that pretreatment intraindividual variability was the only predictor of improvement in performance on the repetition test, with greater pretreatment variability predicting greater improvement. Furthermore, the degree of reduction in this variability over the course of treatment was positively correlated with the degree of improvement. Intraindividual variability may be indicative of potential for improvement on a given task, with more uniform performance suggesting functioning at or near peak potential. © The Author(s) 2016.

Improving stability and curving passing performance for railway vehicles with a variable stiffness MRF rubber joint

NASA Astrophysics Data System (ADS)

Harris, B. J.; Sun, S. S.; Li, W. H.

2017-03-01

With the growing need for effective intercity transport, the need for more advanced rail vehicle technology has never been greater. The conflicting primary longitudinal suspension requirements of high speed stability and curving performance limit the development of rail vehicle technology. This paper presents a novel magnetorheological fluid based joint with variable stiffness characteristics for the purpose of overcoming this parameter conflict. Firstly, the joint design and working principle is developed. Following this, a prototype is tested by MTS to characterize its variable stiffness properties under a range of conditions. Lastly, the performance of the proposed MRF rubber joint with regard to improving train stability and curving performance is numerically evaluated.

Non-Conventional Carbon Nanotube Skeleton Reinforced Composites for Space Applications

NASA Astrophysics Data System (ADS)

Hepp, Felicitas; Pfeiffer, E. K.; Pereira, C.; Martins, M.; Liedtke, V.; Macho, C.; Aschenbrenner, O.; Forero, S.; Linke, S.; Masouras, A.; Vavouliotis, A.; Kostopoulos, V.; Wulz, H.-G.; Pambaguian, L.

2014-06-01

Carbon Nanotubes (CNT) embedded in composite materials like CFRP, polymers or ceramics, can improve specific performance characteristics such as e.g. electrical conductivity, mechanical fatigue and crack propagation, mechanical properties, alpha/epsilon values, PIM-reduction, EMC shielding, etc.CNT skeletons, also called Bucky papers and Bucky discs, are macroscopic aggregates of Carbon Nanotubes. These skeletons are used in composites with different matrices, namely metal, ceramic or polymer or directly used in CFRP composites.The aim is to increase the performance of composite space structures by increasing the material characteristics or provide composites with additional sensing abilities like structural health monitoring.

Apply TQM to E-Government Outsourcing Management

NASA Astrophysics Data System (ADS)

Huai, Jinmei

This paper developed an approach to e-government outsourcing quality management. E-government initiatives have rapidly increased in the last decades and the success of these activities will largely depend on their operation quality. As an instrument to improve operation quality, outsourcing can be applied to e-government. This paper inspected process of e-government outsourcing and discussed how to improve the outsourcing performance through total quality management (TQM). The characteristics and special requirements of e-government outsourcing were analyzed as the basis for discussion. Then the principles and application of total quality management were interpreted. Finally the process of improving performance of e-government was analyzed in the context of outsourcing.

Contamination avoidance devices for poppettype shutoff valves

NASA Technical Reports Server (NTRS)

Endicott, D. L.

1973-01-01

The determination of the cycle life is reported of the scal closure of a typical poppet-type shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O3 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full-flow and cyclic-operating conditions, redesigned to improve the damage tolerance to contaminants, and then retested. The redesigned valve was found to have acceptable tolerance characteristics under all full-flow conditions and cyclic operation with small (25-75 microns) particulate contamination. The tolerance characteristics of the valve under cyclic conditions with large (75-250 microns) particulate contamination was improved but was not found to be completely satisfactory.

Hydraulic performance improvement of the bidirectional pit pump installation based on CFD

NASA Astrophysics Data System (ADS)

Chen, H. X.; Zhou, D. Q.

2013-12-01

At present, the efficiency of bidirectional pit pump installation with lift under 2m is still low because of lack of research on it in the past. In the paper, the CFD numerical method and experimental test were applied to study flow characteristic of bidirectional pit pump installation under positive and reverse condition. Through changing airfoil type and position of blade and stay vane, the comprehensive performance of improved model were obtained by calculating many different models. The results showed that when improved model is obtained with type A runner with 4 blades that is 0.7D away from pit exit and unsymmetrical guide vane 0.25dh which away from the impeller outlet, and the flow pattern of the improved solution is steady with high efficiency. Compared with the original scheme, the efficiency of positive and reverse design condition reach to 67.23% and 58.32% respectively, which is increased 6% more than original model on the design condition and 5% on the optimum operating condition, and it achieved the purpose of improvement. According to the runner blade angle of the optimization solution, model synthetic characteristic curve was drawn and internal flow field characteristics was analyzed under optimal positive and reverse conditions. The numerical calculation shows that owing to the lack of stay vane to recycle the energy in outlet runner chamber, the water flow regime is not steady enough in the outlet passage, and that is the main reason for lower efficiency at reverse condition than that at positive condition.

Time-resolved 3D MR velocity mapping at 3T: improved navigator-gated assessment of vascular anatomy and blood flow.

PubMed

Markl, Michael; Harloff, Andreas; Bley, Thorsten A; Zaitsev, Maxim; Jung, Bernd; Weigang, Ernst; Langer, Mathias; Hennig, Jürgen; Frydrychowicz, Alex

2007-04-01

To evaluate an improved image acquisition and data-processing strategy for assessing aortic vascular geometry and 3D blood flow at 3T. In a study with five normal volunteers and seven patients with known aortic pathology, prospectively ECG-gated cine three-dimensional (3D) MR velocity mapping with improved navigator gating, real-time adaptive k-space ordering and dynamic adjustment of the navigator acceptance criteria was performed. In addition to morphological information and three-directional blood flow velocities, phase-contrast (PC)-MRA images were derived from the same data set, which permitted 3D isosurface rendering of vascular boundaries in combination with visualization of blood-flow patterns. Analysis of navigator performance and image quality revealed improved scan efficiencies of 63.6%+/-10.5% and temporal resolution (<50 msec) compared to previous implementations. Semiquantitative evaluation of image quality by three independent observers demonstrated excellent general image appearance with moderate blurring and minor ghosting artifacts. Results from volunteer and patient examinations illustrate the potential of the improved image acquisition and data-processing strategy for identifying normal and pathological blood-flow characteristics. Navigator-gated time-resolved 3D MR velocity mapping at 3T in combination with advanced data processing is a powerful tool for performing detailed assessments of global and local blood-flow characteristics in the aorta to describe or exclude vascular alterations. Copyright (c) 2007 Wiley-Liss, Inc.

Illustrating Performance Indicators and Course Characteristics to Support Students' Self-Regulated Learning in CS1

ERIC Educational Resources Information Center

Ott, Claudia; Robins, Anthony; Haden, Patricia; Shephard, Kerry

2015-01-01

In higher education, quality feedback for students is regarded as one of the main contributors to improve student learning. Feedback to support students' development into self-regulated learners, who set their own goals, self-monitor their actual performance according to these goals, and adjust learning strategies if necessary, is seen as an…

Optimal visual simulation of the self-tracking combustion of the infrared decoy based on the particle system

NASA Astrophysics Data System (ADS)

Hu, Qi; Duan, Jin; Wang, LiNing; Zhai, Di

2016-09-01

The high-efficiency simulation test of military weapons has a very important effect on the high cost of the actual combat test and the very demanding operational efficiency. Especially among the simulative emulation methods of the explosive smoke, the simulation method based on the particle system has generated much attention. In order to further improve the traditional simulative emulation degree of the movement process of the infrared decoy during the real combustion cycle, this paper, adopting the virtual simulation platform of OpenGL and Vega Prime and according to their own radiation characteristics and the aerodynamic characteristics of the infrared decoy, has simulated the dynamic fuzzy characteristics of the infrared decoy during the real combustion cycle by using particle system based on the double depth peeling algorithm and has solved key issues such as the interface, coordinate conversion and the retention and recovery of the Vega Prime's status. The simulation experiment has basically reached the expected improvement purpose, effectively improved the simulation fidelity and provided theoretical support for improving the performance of the infrared decoy.

Error reduction by combining strapdown inertial measurement units in a baseball stitch

NASA Astrophysics Data System (ADS)

Tracy, Leah

A poor musical performance is rarely due to an inferior instrument. When a device is under performing, the temptation is to find a better device or a new technology to achieve performance objectives; however, another solution may be improving how existing technology is used through a better understanding of device characteristics, i.e., learning to play the instrument better. This thesis explores improving position and attitude estimates of inertial navigation systems (INS) through an understanding of inertial sensor errors, manipulating inertial measurement units (IMUs) to reduce that error and multisensor fusion of multiple IMUs to reduce error in a GPS denied environment.

Effect of organic calcium compounds on combustion characteristics of rice husk, sewage sludge, and bituminous coal: thermogravimetric investigation.

PubMed

Zhang, Lihui; Duan, Feng; Huang, Yaji

2015-04-01

Experiments were conducted in a thermogravimetric analyzer to assess the enhancement of combustion characteristics of different solid fuels blended with organic calcium compounds (OCCs). Rice husk, sewage sludge, and bituminous coal, and two OCC were used in this study. Effect of different mole ratios of calcium to sulfur (Ca/S ratio) on the combustion characteristics were also investigated. Results indicated that combustion performance indexes for bituminous coal impregnated by OCC were improved, however, an inverse trend was found for sewage sludge because sewage sludge has lower ignition temperature and higher volatile matter content compared to those of OCC. For rice husk, effect of added OCC on the combustion characteristics is not obvious. Different solid fuels show different combustion characteristics with increases of Ca/S ratio. The maximum combustion performance indexes appear at Ca/S ratios of 1:1, 2:1, and 3:1 for OCC blended with Shenhua coal, rice husk, and sewage sludge, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fretting wear study of surface modified Ni-Ti shape memory alloy.

PubMed

Tan, L; Crone, W C; Sridharan, K

2002-05-01

A combination of shape memory characteristics, pseudoelasticity, and good damping properties make near-equiatomic nickel-titanium (Ni-Ti) alloy a desirable candidate material for certain biomedical device applications. The alloy has moderately good wear resistance, however, further improvements in this regard would be beneficial from the perspective of reducing wear debris generation, improving biocompatibility, and preventing failure during service. Fretting wear tests of Ni-Ti in both austenitic and martensitic microstructural conditions were performed with the goal of simulating wear which medical devices such as stents may experience during surgical implantation or service. The tests were performed using a stainless steel stylus counter-wearing surface under dry conditions and also with artificial plasma containing 80 g/L albumen protein as lubricant. Additionally, the research explores the feasibility of surface modification by sequential ion implantation with argon and oxygen to enhance the wear characteristics of the Ni-Ti alloy. Each of these implantations was performed to a dose of 3 x 10(17) atom/cm(2) and an energy of 50 kV, using the plasma source ion implantation process. Improvements in wear resistance were observed for the austenitic samples implanted with argon and oxygen. Ion implantation with argon also reduced the surface Ni content with respect to Ti due to differential sputtering rates of the two elements, an effect that points toward improved biocompatibility.

Classification accuracy of claims-based methods for identifying providers failing to meet performance targets.

PubMed

Hubbard, Rebecca A; Benjamin-Johnson, Rhondee; Onega, Tracy; Smith-Bindman, Rebecca; Zhu, Weiwei; Fenton, Joshua J

2015-01-15

Quality assessment is critical for healthcare reform, but data sources are lacking for measurement of many important healthcare outcomes. With over 49 million people covered by Medicare as of 2010, Medicare claims data offer a potentially valuable source that could be used in targeted health care quality improvement efforts. However, little is known about the operating characteristics of provider profiling methods using claims-based outcome measures that may estimate provider performance with error. Motivated by the example of screening mammography performance, we compared approaches to identifying providers failing to meet guideline targets using Medicare claims data. We used data from the Breast Cancer Surveillance Consortium and linked Medicare claims to compare claims-based and clinical estimates of cancer detection rate. We then demonstrated the performance of claim-based estimates across a broad range of operating characteristics using simulation studies. We found that identification of poor performing providers was extremely sensitive to algorithm specificity, with no approach identifying more than 65% of poor performing providers when claims-based measures had specificity of 0.995 or less. We conclude that claims have the potential to contribute important information on healthcare outcomes to quality improvement efforts. However, to achieve this potential, development of highly accurate claims-based outcome measures should remain a priority. Copyright © 2014 John Wiley & Sons, Ltd.

Patient-centered Medical Home Capability and Clinical Performance in HRSA-supported Health Centers

PubMed Central

Shi, Leiyu; Lock, Diana C.; Lee, De-Chih; Lebrun-Harris, Lydie A.; Chin, Marshall H.; Chidambaran, Preeta; Nocon, Robert S.; Zhu, Jinsheng; Sripipatana, Alek

2015-01-01

Objectives To evaluate the relationship between Patient-centered Medical Home (PCMH) model adoption in health centers (HCs) and clinical performance measures and to determine if adoption of PCMH characteristics is associated with better clinical performance. Research Design Data came from the Health Resources and Services Administration’s 2009 Uniform Data System and the 2009 Commonwealth Fund National Survey of Federally Qualified Health Centers. Clinical performance measures included 2 process measures (childhood immunization and cervical cancer screening) and 2 outcome measures (hypertension control and diabetes control). Total and subscale PCMH scores were regressed on the clinical performance measures, adjusting for patient, provider, financial, and institutional characteristics. Results The findings showed different directional relationships, with some PCMH domains (care management, test/referral tracking, quality improvement, and external coordination) showing little or no effect on outcome measures of interest, 1 domain (access/communication) associated with improved outcomes, and 1 domain (patient tracking/registry) associated with worse outcomes. Conclusions This study is among the first to examine the association between PCMH transformation and clinical performance in HCs, providing an understanding of the impact of PCMH adoption within safety-net settings. The mixed results highlight the importance of examining relationships between specific PCMH domains and specific clinical quality measures, in addition to analyzing overall PCMH scores which could yield distorted findings. PMID:25793267

Improving the signal subtle feature extraction performance based on dual improved fractal box dimension eigenvectors

NASA Astrophysics Data System (ADS)

Chen, Xiang; Li, Jingchao; Han, Hui; Ying, Yulong

2018-05-01

Because of the limitations of the traditional fractal box-counting dimension algorithm in subtle feature extraction of radiation source signals, a dual improved generalized fractal box-counting dimension eigenvector algorithm is proposed. First, the radiation source signal was preprocessed, and a Hilbert transform was performed to obtain the instantaneous amplitude of the signal. Then, the improved fractal box-counting dimension of the signal instantaneous amplitude was extracted as the first eigenvector. At the same time, the improved fractal box-counting dimension of the signal without the Hilbert transform was extracted as the second eigenvector. Finally, the dual improved fractal box-counting dimension eigenvectors formed the multi-dimensional eigenvectors as signal subtle features, which were used for radiation source signal recognition by the grey relation algorithm. The experimental results show that, compared with the traditional fractal box-counting dimension algorithm and the single improved fractal box-counting dimension algorithm, the proposed dual improved fractal box-counting dimension algorithm can better extract the signal subtle distribution characteristics under different reconstruction phase space, and has a better recognition effect with good real-time performance.

Assimilation of Web-Based Urgent Stroke Evaluation: A Qualitative Study of Two Networks

PubMed Central

Mathiassen, Lars; Switzer, Jeffrey A; Adams, Robert J

2014-01-01

Background Stroke is a leading cause of death and serious, long-term disability across the world. Urgent stroke care treatment is time-sensitive and requires a stroke-trained neurologist for clinical diagnosis. Rural areas, where neurologists and stroke specialists are lacking, have a high incidence of stroke-related death and disability. By virtually connecting emergency department physicians in rural hospitals to regional medical centers for consultations, specialized Web-based stroke evaluation systems (telestroke) have helped address the challenge of urgent stroke care in underserved communities. However, many rural hospitals that have deployed telestroke have not fully assimilated this technology. Objective The objective of this study was to explore potential sources of variations in the utilization of a Web-based telestroke system for urgent stroke evaluation and propose a telestroke assimilation model to improve stroke care performance. Methods An exploratory, qualitative case study of two telestroke networks, each comprising an academic stroke center (hub) and connected rural hospitals (spokes), was conducted. Data were collected from 50 semistructured interviews with 40 stakeholders, telestroke usage logs from 32 spokes, site visits, published papers, and reports. Results The two networks used identical technology (called Remote Evaluation of Acute isCHemic stroke, REACH) and were of similar size and complexity, but showed large variations in telestroke assimilation across spokes. Several observed hub- and spoke-related characteristics can explain these variations. The hub-related characteristics included telestroke institutionalization into stroke care, resources for the telestroke program, ongoing support for stroke readiness of spokes, telestroke performance monitoring, and continuous telestroke process improvement. The spoke-related characteristics included managerial telestroke championship, stroke center certification, dedicated telestroke coordinator, stroke committee of key stakeholders, local neurological expertise, and continuous telestroke process improvement. Conclusions Rural hospitals can improve their stroke readiness with use of telestroke systems. However, they need to integrate the technology into their stroke delivery processes. A telestroke assimilation model may improve stroke care performance. PMID:25601232

Improving color characteristics of LCD

NASA Astrophysics Data System (ADS)

Feng, Xiao-fan; Daly, Scott J.

2005-01-01

The drive for larger size, higher spatial resolution, and wider aperture LCD has shown to increase the electrical crosstalk between electrodes in the driver circuit. This crosstalk leads to additivity errors in color LCD. In this paper, the crosstalk effect was analyzed with micrographs captured from an imaging colorimeter. The experimental result reveals the subpixel nature of color crosstalk. A spatial-based subpixel crosstalk correction algorithm was developed to improve the color performance of LCD. Compared to a 3D lookup table approach, the new algorithm is easier to implement and more accurate in performance.

Flight investigation of an air-cooled plug nozzle with afterburning turbojet

NASA Technical Reports Server (NTRS)

Samanich, N. E.

1972-01-01

A convectively cooled plug nozzle, using 4 percent of the engine air as the coolant, was tested in 1967 K (3540 R) temperature exhaust gas. No significant differences in cooling characteristics existed between flight and static results. At flight speeds above Mach 1.1, nozzle performance was improved by extending the outer shroud. Increasing engine power improved nozzle efficiency considerably more at Mach 1.2 than at 0.9. The effect of nozzle pressure ratio and secondary weight flow on nozzle performance are also presented.

Charge transfer through amino groups-small molecules interface improving the performance of electroluminescent devices

NASA Astrophysics Data System (ADS)

Havare, Ali Kemal; Can, Mustafa; Tozlu, Cem; Kus, Mahmut; Okur, Salih; Demic, Şerafettin; Demirak, Kadir; Kurt, Mustafa; Icli, Sıddık

2016-05-01

A carboxylic group functioned charge transporting was synthesized and self-assembled on an indium tin oxide (ITO) anode. A typical electroluminescent device [modified ITO/TPD (50 nm)/Alq3 (60 nm)/LiF (2 nm)/(120 nm)] was fabricated to investigate the effect of the amino groups-small molecules interface on the characteristics of the device. The increase in the surface work function of ITO is expected to facilitate the hole injection from the ITO anode to the Hole Transport Layer (HTL) in electroluminescence. The modified electroluminescent device could endure a higher current and showed a much higher luminance than the nonmodified one. For the produced electroluminescent devices, the I-V characteristics, optical characterization and quantum yields were performed. The external quantum efficiency of the modified electroluminescent device is improved as the result of the presence of the amino groups-small molecules interface.

Effect of tumor resection on the characteristics of functional brain networks.

PubMed

Wang, H; Douw, L; Hernández, J M; Reijneveld, J C; Stam, C J; Van Mieghem, P

2010-08-01

Brain functioning such as cognitive performance depends on the functional interactions between brain areas, namely, the functional brain networks. The functional brain networks of a group of patients with brain tumors are measured before and after tumor resection. In this work, we perform a weighted network analysis to understand the effect of neurosurgery on the characteristics of functional brain networks. Statistically significant changes in network features have been discovered in the beta (13-30 Hz) band after neurosurgery: the link weight correlation around nodes and within triangles increases which implies improvement in local efficiency of information transfer and robustness; the clustering of high link weights in a subgraph becomes stronger, which enhances the global transport capability; and the decrease in the synchronization or virus spreading threshold, revealed by the increase in the largest eigenvalue of the adjacency matrix, which suggests again the improvement of information dissemination.

Development of lead salt semiconductor lasers for the 9-17 micron spectral region

NASA Technical Reports Server (NTRS)

Linden, K. J.; Butler, J. F.; Nill, K. W.; Reeder, R. E.

1981-01-01

Improved diode lasers of Pb sub 1-x Sn sub x Se operating in the 9-17 micrometers spectral region were developed. The performance characteristics of the best lasers exceeded the contract goals of 500 microW/mode at T 30K in the 9-12 micrometers region and 200 microW/mode at T 18K in the 16-17 micrometers region. Increased reliability and device yields resulted from processing improvements which evolved from a series of diagnostic studies. By means of Auger electron spectroscopy, laser shelf storage degradation was shown to be characterized by the presence of In metal on the semiconductor crystal surfaces. Studies of various metal barrier layers between the crystals and the In metal led to the development of an improved metallurgical contacting technology which has resulted in devices with performance stability values exceeding the contract goal of a one year shelf life. Lasers cycled over 500 times between 300K and 77K were also shown to be stable. Studies on improved methods of fabricating striped geometry lasers indicated that good spectral mode characteristics resulted from lasers which stripe widths of 12 and 25 micrometers.

Job Demands-Control-Support model and employee safety performance.

PubMed

Turner, Nick; Stride, Chris B; Carter, Angela J; McCaughey, Deirdre; Carroll, Anthony E

2012-03-01

The aim of this study was to explore whether work characteristics (job demands, job control, social support) comprising Karasek and Theorell's (1990) Job Demands-Control-Support framework predict employee safety performance (safety compliance and safety participation; Neal and Griffin, 2006). We used cross-sectional data of self-reported work characteristics and employee safety performance from 280 healthcare staff (doctors, nurses, and administrative staff) from Emergency Departments of seven hospitals in the United Kingdom. We analyzed these data using a structural equation model that simultaneously regressed safety compliance and safety participation on the main effects of each of the aforementioned work characteristics, their two-way interactions, and the three-way interaction among them, while controlling for demographic, occupational, and organizational characteristics. Social support was positively related to safety compliance, and both job control and the two-way interaction between job control and social support were positively related to safety participation. How work design is related to employee safety performance remains an important area for research and provides insight into how organizations can improve workplace safety. The current findings emphasize the importance of the co-worker in promoting both safety compliance and safety participation. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Amplifier circuit operable over a wide temperature range

DOEpatents

Kelly, Ronald D.; Cannon, William L.

1979-01-01

An amplifier circuit having stable performance characteristics over a wide temperature range from approximately 0.degree. C up to as high as approximately 500.degree. C, such as might be encountered in a geothermal borehole. The amplifier utilizes ceramic vacuum tubes connected in directly coupled differential amplifier pairs having a common power supply and a cathode follower output stage. In an alternate embodiment, for operation up to 500.degree. C, positive and negative power supplies are utilized to provide improved gain characteristics, and all electrical connections are made by welding. Resistor elements in this version of the invention are specially heat treated to improve their stability with temperature.

The Pharmacology of Actoprotectors: Practical Application for Improvement of Mental and Physical Performance

PubMed Central

Oliynyk, Sergiy; Oh, Seikwan

2012-01-01

Actoprotectors are preparations that enhance body stability against physical loads without increasing oxygen consumption or heat production. Or, in short, actoprotectors are synthetic adaptogens with a significant capacity to improve physical performance. This paper explores the history of actoprotectors’development, their pharmacological properties, mechanism of action, and practical application to the improvement of mental and physical performance. A brief summary of the clinico-pharmacological characteristics of the main representatives of this class (bemitil and bromantane) is provided. Some other synthesized compounds, and even natural ones such as ginseng, also are regarded as potential actoprotectors, and these are treated herein as well. Actoprotectors, owing to their wide-ranging pharmacological activities, high efficiency and safety, can be applied under either normal or extreme conditions. PMID:24009833

Effects of the F₄TCNQ-Doped Pentacene Interlayers on Performance Improvement of Top-Contact Pentacene-Based Organic Thin-Film Transistors.

PubMed

Fan, Ching-Lin; Lin, Wei-Chun; Chang, Hsiang-Sheng; Lin, Yu-Zuo; Huang, Bohr-Ran

2016-01-13

In this paper, the top-contact (TC) pentacene-based organic thin-film transistor (OTFT) with a tetrafluorotetracyanoquinodimethane (F₄TCNQ)-doped pentacene interlayer between the source/drain electrodes and the pentacene channel layer were fabricated using the co-evaporation method. Compared with a pentacene-based OTFT without an interlayer, OTFTs with an F₄TCNQ:pentacene ratio of 1:1 showed considerably improved electrical characteristics. In addition, the dependence of the OTFT performance on the thickness of the F₄TCNQ-doped pentacene interlayer is weaker than that on a Teflon interlayer. Therefore, a molecular doping-type F₄TCNQ-doped pentacene interlayer is a suitable carrier injection layer that can improve the TC-OTFT performance and facilitate obtaining a stable process window.

Heat transfer enhancement in a lithium-ion cell through improved material-level thermal transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vishwakarma, Vivek; Waghela, Chirag; Wei, Zi

2016-09-25

We report that while Li-ion cells offer excellent electrochemical performance for several applications including electric vehicles, they also exhibit poor thermal transport characteristics, resulting in reduced performance, overheating and thermal runaway. Inadequate heat removal from Li-ion cells originates from poor thermal conductivity within the cell. This paper identifies the rate-limiting material-level process that dominates overall thermal conduction in a Li-ion cell. Results indicate that thermal characteristics of a Li-ion cell are largely dominated by heat transfer across the cathode-separator interface rather than heat transfer through the materials themselves. This interfacial thermal resistance contributes around 88% of total thermal resistance inmore » the cell. Measured value of interfacial resistance is close to that obtained from theoretical models that account for weak adhesion and large acoustic mismatch between cathode and separator. Further, to address this problem, an amine-based chemical bridging of the interface is carried out. This is shown to result in in four-times lower interfacial thermal resistance without deterioration in electrochemical performance, thereby increasing effective thermal conductivity by three-fold. This improvement is expected to reduce peak temperature rise during operation by 60%. Finally, by identifying and addressing the material-level root cause of poor thermal transport in Li-ion cells, this work may contribute towards improved thermal performance of Li-ion cells.« less

Cancer and treatment effects on job task performance for gynecological cancer survivors.

PubMed

Nachreiner, Nancy M; Shanley, Ryan; Ghebre, Rahel G

2013-01-01

Over 91,000 new cases of gynecological cancers are expected to be diagnosed in 2013 in the US alone. As cancer detection technology and treatment options improve, the number of working-age cancer survivors continues to grow. To describe US gynecological cancer survivors' perceptions of the effects of cancer and treatment on their job tasks. 104 adult gynecological cancer survivors who were working at the time of their cancer diagnosis, treated at a University-based women's health clinic, diagnosed in the previous 24 months, and spoke English. Women completed written surveys to describe their work experiences following diagnosis. Clinical characteristics were obtained through medical record review. Descriptive statistics and cross tabulations were performed to describe characteristics and associations. Fifteen percent of women had chemotherapy and radiation treatment; 48% had only chemotherapy, 9% only radiation therapy, and 28% had neither. Survivors described the frequency of performing seven job tasks, such as 'intense concentration', 'analyzing data', and 'lifting heavy loads.' Women who had undergone radiation treatment were more likely to indicate limitations for physical tasks; women undergoing chemotherapy were more likely to report limitations in more analytic tasks. Only 29% of women noted an employer-based policy facilitated their return-to-work process. Cancer and treatment have important effects on job performance and may vary by type of treatment. Employer-based policies focusing on improved communication and work accommodations may improve the return to work process.

Lick sodium laser guide star: performance during the 1998 LGS observing campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauman, B; Friedman, H; Gavel, D T

1999-07-19

The performance of a sodium laser guide star adaptive optics system depends crucially on the characteristics of the laser guide star in the sodium layer. System performance is quite sensitive to sodium layer spot radiance, that is, return per unit sterradian on the sky, hence we have been working to improve projected beam quality via improvements to the laser and changes to the launched beam format. The laser amplifier was reconfigured to a ''bounce-beam'' geometry, which considerably improves wavefront quality and allows a larger round instead of square launch beam aperture. The smaller beacon makes it easier to block themore » unwanted Rayleigh light and improves the accuracy of Hartmann sensor wavefront measurements in the A0 system. We present measurements of the beam quality and of the resulting sodium beacon and compare to similar measurements from last year.« less

Interprofessional Communication Skills Training for Serious Illness: Evaluation of a Small-Group, Simulated Patient Intervention

PubMed Central

Bays, Alison M.; Engelberg, Ruth A.; Back, Anthony L.; Ford, Dee W.; Downey, Lois; Shannon, Sarah E.; Doorenbos, Ardith Z.; Edlund, Barbara; Christianson, Phyllis; Arnold, Richard W.; O'Connor, Kim; Kross, Erin K.; Reinke, Lynn F.; Cecere Feemster, Laura; Fryer-Edwards, Kelly; Alexander, Stewart C.; Tulsky, James A.

2014-01-01

Abstract Background: Communication with patients and families is an essential component of high-quality care in serious illness. Small-group skills training can result in new communication behaviors, but past studies have used facilitators with extensive experience, raising concerns this is not scalable. Objective: The objective was to investigate the effect of an experiential communication skills building workshop (Codetalk), led by newly trained facilitators, on internal medicine trainees' and nurse practitioner students' ability to communicate bad news and express empathy. Design: Trainees participated in Codetalk; skill improvement was evaluated through pre- and post- standardized patient (SP) encounters. Setting and subjects: The subjects were internal medicine residents and nurse practitioner students at two universities. Intervention and measurements: The study was carried out in anywhere from five to eight half-day sessions over a month. The first and last sessions included audiotaped trainee SP encounters coded for effective communication behaviors. The primary outcome was change in communication scores from pre-intervention to post-intervention. We also measured trainee characteristics to identify predictors of performance and change in performance over time. Results: We enrolled 145 trainees who completed pre- and post-intervention SP interviews—with participation rates of 52% for physicians and 14% for nurse practitioners. Trainees' scores improved in 8 of 11 coded behaviors (p<0.05). The only significant predictors of performance were having participated in the intervention (p<0.001) and study site (p<0.003). The only predictor of improvement in performance over time was participating in the intervention (p<0.001). Conclusions: A communication skills intervention using newly trained facilitators was associated with improvement in trainees' skills in giving bad news and expressing empathy. Improvement in communication skills did not vary by trainee characteristics. PMID:24180700

Interprofessional communication skills training for serious illness: evaluation of a small-group, simulated patient intervention.

PubMed

Bays, Alison M; Engelberg, Ruth A; Back, Anthony L; Ford, Dee W; Downey, Lois; Shannon, Sarah E; Doorenbos, Ardith Z; Edlund, Barbara; Christianson, Phyllis; Arnold, Richard W; O'Connor, Kim; Kross, Erin K; Reinke, Lynn F; Cecere Feemster, Laura; Fryer-Edwards, Kelly; Alexander, Stewart C; Tulsky, James A; Curtis, J Randall

2014-02-01

Communication with patients and families is an essential component of high-quality care in serious illness. Small-group skills training can result in new communication behaviors, but past studies have used facilitators with extensive experience, raising concerns this is not scalable. The objective was to investigate the effect of an experiential communication skills building workshop (Codetalk), led by newly trained facilitators, on internal medicine trainees' and nurse practitioner students' ability to communicate bad news and express empathy. Trainees participated in Codetalk; skill improvement was evaluated through pre- and post- standardized patient (SP) encounters. The subjects were internal medicine residents and nurse practitioner students at two universities. The study was carried out in anywhere from five to eight half-day sessions over a month. The first and last sessions included audiotaped trainee SP encounters coded for effective communication behaviors. The primary outcome was change in communication scores from pre-intervention to post-intervention. We also measured trainee characteristics to identify predictors of performance and change in performance over time. We enrolled 145 trainees who completed pre- and post-intervention SP interviews-with participation rates of 52% for physicians and 14% for nurse practitioners. Trainees' scores improved in 8 of 11 coded behaviors (p<0.05). The only significant predictors of performance were having participated in the intervention (p<0.001) and study site (p<0.003). The only predictor of improvement in performance over time was participating in the intervention (p<0.001). A communication skills intervention using newly trained facilitators was associated with improvement in trainees' skills in giving bad news and expressing empathy. Improvement in communication skills did not vary by trainee characteristics.

An innovative approach to achieve re-centering and ductility of cement mortar beams through randomly distributed pseudo-elastic shape memory alloy fibers

NASA Astrophysics Data System (ADS)

Shajil, N.; Srinivasan, S. M.; Santhanam, M.

2012-04-01

Fibers can play a major role in post cracking behavior of concrete members, because of their ability to bridge cracks and distribute the stress across the crack. Addition of steel fibers in mortar and concrete can improve toughness of the structural member and impart significant energy dissipation through slow pull out. However, steel fibers undergo plastic deformation at low strain levels, and cannot regain their shape upon unloading. This is a major disadvantage in strong cyclic loading conditions, such as those caused by earthquakes, where self-centering ability of the fibers is a desired characteristic in addition to ductility of the reinforced cement concrete. Fibers made from an alternative material such as shape memory alloy (SMA) could offer a scope for re-centering, thus improving performance especially after a severe loading has occurred. In this study, the load-deformation characteristics of SMA fiber reinforced cement mortar beams under cyclic loading conditions were investigated to assess the re-centering performance. This study involved experiments on prismatic members, and related analysis for the assessment and prediction of re-centering. The performances of NiTi fiber reinforced mortars are compared with mortars with same volume fraction of steel fibers. Since re-entrant corners and beam columns joints are prone to failure during a strong ground motion, a study was conducted to determine the behavior of these reinforced with NiTi fiber. Comparison is made with the results of steel fiber reinforced cases. NiTi fibers showed significantly improved re-centering and energy dissipation characteristics compared to the steel fibers.

Research on Intelligent Synthesis Environment

NASA Technical Reports Server (NTRS)

Loftin, R. Bowen; Dryer, David; Major, Debra; Fletcher, Tom

2002-01-01

The ultimate goal of this research project is to develop a methodology for the assessment and continuous improvement of engineering team effectiveness in distributed collaborative environments. This review provides the theoretical foundation upon which subsequent empirical work will be based. Our review of the team performance literature has identified the following 12 conceptually distinct team interaction processes as characteristic of effective teams. 1) Mission Analysis; 2) Resource Distribution; 3) Leadership; 4) Timing; 5) Intra-team Feedback; 6) Motivational Functions; 7) Team Orientation; 8) Communication; 9) Coordination; 10) Mutual Performance Monitoring; 11) Back-up Behaviors; and 12) Cooperation. In addition, this review summarizes how team task characteristics (i.e., task type, task complexity, motivation, and temporal changes), team characteristics (i.e., team structure and team knowledge), and individual team member characteristics (i.e., dispositions and teamwork knowledge, skills, and abilities) affect team interaction processes, determine the relevance of these processes, and influence team performance. The costs and benefits of distributed team collaboration are also considered. The review concludes with a brief discussion of the nature of collaborative team engineering tasks.

Research on Intelligent Synthesis Environment

NASA Astrophysics Data System (ADS)

Loftin, R. Bowen; Dryer, David; Major, Debra; Fletcher, Tom

2002-10-01

The ultimate goal of this research project is to develop a methodology for the assessment and continuous improvement of engineering team effectiveness in distributed collaborative environments. This review provides the theoretical foundation upon which subsequent empirical work will be based. Our review of the team performance literature has identified the following 12 conceptually distinct team interaction processes as characteristic of effective teams. 1) Mission Analysis; 2) Resource Distribution; 3) Leadership; 4) Timing; 5) Intra-team Feedback; 6) Motivational Functions; 7) Team Orientation; 8) Communication; 9) Coordination; 10) Mutual Performance Monitoring; 11) Back-up Behaviors; and 12) Cooperation. In addition, this review summarizes how team task characteristics (i.e., task type, task complexity, motivation, and temporal changes), team characteristics (i.e., team structure and team knowledge), and individual team member characteristics (i.e., dispositions and teamwork knowledge, skills, and abilities) affect team interaction processes, determine the relevance of these processes, and influence team performance. The costs and benefits of distributed team collaboration are also considered. The review concludes with a brief discussion of the nature of collaborative team engineering tasks.

[Research on fast detecting tomato seedlings nitrogen content based on NIR characteristic spectrum selection].

PubMed

Wu, Jing-zhu; Wang, Feng-zhu; Wang, Li-li; Zhang, Xiao-chao; Mao, Wen-hua

2015-01-01

In order to improve the accuracy and robustness of detecting tomato seedlings nitrogen content based on near-infrared spectroscopy (NIR), 4 kinds of characteristic spectrum selecting methods were studied in the present paper, i. e. competitive adaptive reweighted sampling (CARS), Monte Carlo uninformative variables elimination (MCUVE), backward interval partial least squares (BiPLS) and synergy interval partial least squares (SiPLS). There were totally 60 tomato seedlings cultivated at 10 different nitrogen-treatment levels (urea concentration from 0 to 120 mg . L-1), with 6 samples at each nitrogen-treatment level. They are in different degrees of over nitrogen, moderate nitrogen, lack of nitrogen and no nitrogen status. Each sample leaves were collected to scan near-infrared spectroscopy from 12 500 to 3 600 cm-1. The quantitative models based on the above 4 methods were established. According to the experimental result, the calibration model based on CARS and MCUVE selecting methods show better performance than those based on BiPLS and SiPLS selecting methods, but their prediction ability is much lower than that of the latter. Among them, the model built by BiPLS has the best prediction performance. The correlation coefficient (r), root mean square error of prediction (RMSEP) and ratio of performance to standard derivate (RPD) is 0. 952 7, 0. 118 3 and 3. 291, respectively. Therefore, NIR technology combined with characteristic spectrum selecting methods can improve the model performance. But the characteristic spectrum selecting methods are not universal. For the built model based or single wavelength variables selection is more sensitive, it is more suitable for the uniform object. While the anti-interference ability of the model built based on wavelength interval selection is much stronger, it is more suitable for the uneven and poor reproducibility object. Therefore, the characteristic spectrum selection will only play a better role in building model, combined with the consideration of sample state and the model indexes.

Effects of modified constraint-induced movement therapy on reach-to-grasp movements and functional performance after chronic stroke: a randomized controlled study.

PubMed

Lin, K-C; Wu, C-Y; Wei, T-H; Lee, C-Y; Liu, J-S

2007-12-01

To evaluate changes in (1) motor control characteristics of the hemiparetic hand during the performance of a functional reach-to-grasp task and (2) functional performance of daily activities in patients with stroke treated with modified constraint-induced movement therapy. Two-group randomized controlled trial with pretreatment and posttreatment measures. Rehabilitation clinics. Thirty-two chronic stroke patients (21 men, 11 women; mean age=57.9 years, range=43-81 years) 13-26 months (mean 16.3 months) after onset of a first-ever cerebrovascular accident. Thirty-two patients were randomized to receive modified constraint-induced movement therapy (restraint of the unaffected limb combined with intensive training of the affected limb) or traditional rehabilitation for three weeks. Kinematic analysis was used to assess motor control characteristics as patients reached to grasp a beverage can. Functional outcomes were evaluated using the Motor Activity Log and Functional Independence Measure. There were moderate and significant effects of modified constraint-induced movement therapy on some aspects of motor control of reach-to-grasp and on functional ability. The modified constraint-induced movement therapy group preplanned reaching and grasping (P=0.018) more efficiently and depended more on the feedforward control of reaching (P=0.046) than did the traditional rehabilitation group. The modified constraint-induced movement therapy group also showed significantly improved functional performance on the Motor Activity Log (P<0.0001) and the Functional Independence Measure (P=0.016). In addition to improving functional use of the affected arm and daily functioning, modified constraint-induced movement therapy improved motor control strategy during goal-directed reaching, a possible mechanism for the improved movement performance of stroke patients undergoing this therapy.

Impact of Breast Reader Assessment Strategy on mammographic radiologists' test reading performance.

PubMed

Suleiman, Wasfi I; Rawashdeh, Mohammad A; Lewis, Sarah J; McEntee, Mark F; Lee, Warwick; Tapia, Kriscia; Brennan, Patrick C

2016-06-01

The detection of breast cancer is somewhat limited by human factors, and thus there is a need to improve reader performance. This study assesses whether radiologists who regularly undertake the education in the form of the Breast Reader Assessment Strategy (BREAST) demonstrate any changes in mammography interpretation performance over time. In 2011, 2012 and 2013, 14 radiologists independently assessed a year-specific BREAST mammographic test-set. Radiologists read a different single test-set once each year, with each comprising 60 digital mammogram cases. Radiologists marked the location of suspected lesions without computer-aided diagnosis (CAD) and assigned a confidence rating of 2 for benign and 3-5 for malignant lesions. The mean sensitivity, specificity, location sensitivity, JAFROC FOM and ROC AUC were calculated. A Kruskal-Wallis test was used to compare the readings for the 14 radiologists across the 3 years. Wilcoxon signed rank test was used to assess comparison between pairs of years. Relationships between changes in performance and radiologist characteristics were examined using a Spearman's test. Significant increases were noted in mean sensitivity (P = 0.01), specificity (P = 0.01), location sensitivity (P = 0.001) and JAFROC FOM (P = 0.001) between 2011 and 2012. Between 2012 and 2013, significant improvements were noted in mean sensitivity (P = 0.003), specificity (P = 0.002), location sensitivity (P = 0.02), JAFROC FOM (P = 0.005) and ROC AUC (P = 0.008). No statistically significant correlations were shown between the levels of improvement and radiologists' characteristics. Radiologists' who undertake the BREAST programme demonstrate significant improvements in test-set performance during a 3-year period, highlighting the value of ongoing education through the use of test-set. © 2016 The Royal Australian and New Zealand College of Radiologists.

Energy management using virtual reality improves 2000-m rowing performance.

PubMed

Hoffmann, Charles P; Filippeschi, Alessandro; Ruffaldi, Emanuele; Bardy, Benoit G

2014-01-01

Elite-standard rowers tend to use a fast-start strategy followed by an inverted parabolic-shaped speed profile in 2000-m races. This strategy is probably the best to manage energy resources during the race and maximise performance. This study investigated the use of virtual reality (VR) with novice rowers as a means to learn about energy management. Participants from an avatar group (n = 7) were instructed to track a virtual boat on a screen, whose speed was set individually to follow the appropriate to-be-learned speed profile. A control group (n = 8) followed an indoor training programme. In spite of similar physiological characteristics in the groups, the avatar group learned and maintained the required profile, resulting in an improved performance (i.e. a decrease in race duration), whereas the control group did not. These results suggest that VR is a means to learn an energy-related skill and improve performance.

Detailed performance analysis of the A.A.D. - concept B

NASA Technical Reports Server (NTRS)

Sekar, R.; Tozzi, L.

1983-01-01

New concepts for engine performance improvement are seen through the adoption of heat regeneration techniques; advanced methods to enhance the combustion; and higher efficiency air handling machinery, such as the positive displacement helical screw expander and compressor. Each of these concepts plays a particular role in engine performance improvement. First regeneration has a great potential for achieving higher engine thermal efficiency through the recovery of waste energy. Although the concept itself is not new (this technique is used in the gas turbine), the application to reciprocating internal combustion engines is quite unusual and presents conceptual difficulties. The second important area is better control of the combustion process in terms of heat transfer characteristics, combustion products, and heat release rate. The third area for performance improvement is in the adoption of high efficiency air handling machinery. In particular, positive displacement helical expander and compressor exhibit an extremely high efficiency over a wide range of operating conditions.

Growth Performance, Carcass Characteristics and Meat Yield of Boer Goats Fed Diets Containing Leaves or Whole Parts of Andrographis paniculata.

PubMed

Yusuf, A L; Goh, Y M; Samsudin, A A; Alimon, A R; Sazili, A Q

2014-04-01

The study was conducted to determine the effect of feeding diets containing Andrographis paniculata leaves (APL), whole Andrographis paniculata plant (APWP) and a control without Andrographis paniculata (AP0), on growth performance, carcass characteristics and meat yield of 24 intact Boer bucks. The results obtained indicated that inclusion of Andrographis paniculata significantly improved feed intake, weight gain, feed efficiency and live weight. The ratios of carcass to fat, lean to bone, lean to fat, and composition of meat were also improved. In addition, there were significant differences (p<0.05) between the dietary treatments in dressing percentage and chilling loss. Goats fed on AP0 (control) had significantly higher proportions of fat and bone, as well as thicker back fat than the supplemented animals (APL and APWP). Higher gut fill in animals fed Andrographis paniculata suggested slow rate of digestion, which could have improved utilization and absorption of nutrients by the animals. Goats fed Andrographis paniculata also produced higher meat yield and relatively lower fat contents (p<0.05).

Growth Performance, Carcass Characteristics and Meat Yield of Boer Goats Fed Diets Containing Leaves or Whole Parts of Andrographis paniculata

PubMed Central

Yusuf, A. L.; Goh, Y. M.; Samsudin, A. A.; Alimon, A. R.; Sazili, A. Q.

2014-01-01

The study was conducted to determine the effect of feeding diets containing Andrographis paniculata leaves (APL), whole Andrographis paniculata plant (APWP) and a control without Andrographis paniculata (AP0), on growth performance, carcass characteristics and meat yield of 24 intact Boer bucks. The results obtained indicated that inclusion of Andrographis paniculata significantly improved feed intake, weight gain, feed efficiency and live weight. The ratios of carcass to fat, lean to bone, lean to fat, and composition of meat were also improved. In addition, there were significant differences (p<0.05) between the dietary treatments in dressing percentage and chilling loss. Goats fed on AP0 (control) had significantly higher proportions of fat and bone, as well as thicker back fat than the supplemented animals (APL and APWP). Higher gut fill in animals fed Andrographis paniculata suggested slow rate of digestion, which could have improved utilization and absorption of nutrients by the animals. Goats fed Andrographis paniculata also produced higher meat yield and relatively lower fat contents (p<0.05). PMID:25049980

Roll and pitch independently tuned interconnected suspension: modelling and dynamic analysis

NASA Astrophysics Data System (ADS)

Xu, Guangzhong; Zhang, Nong; Roser, Holger M.

2015-12-01

In this paper, a roll and pitch independently tuned hydraulically interconnected passive suspension is presented. Due to decoupling of vibration modes and the improved lateral and longitudinal stability, the stiffness of individual suspension spring can be reduced for improving ride comfort and road grip. A generalised 14 degree-of-freedom nonlinear vehicle model with anti-roll bars is established to investigate the vehicle ride and handling dynamic responses. The nonlinear fluidic model of the hydraulically interconnected suspension is developed and integrated with the full vehicle model to investigate the anti-roll and anti-pitch characteristics. Time domain analysis of the vehicle model with the proposed suspension is conducted under different road excitations and steering/braking manoeuvres. The dynamic responses are compared with conventional suspensions to demonstrate the potential of enhanced ride and handling performance. The results illustrate the model-decoupling property of the hydraulically interconnected system. The anti-roll and anti-pitch performance could be tuned independently by the interconnected systems. With the improved anti-roll and anti-pitch characteristics, the bounce stiffness and ride damping can be optimised for better ride comfort and tyre grip.

Understanding InP Nanowire Array Solar Cell Performance by Nanoprobe-Enabled Single Nanowire Measurements.

PubMed

Otnes, Gaute; Barrigón, Enrique; Sundvall, Christian; Svensson, K Erik; Heurlin, Magnus; Siefer, Gerald; Samuelson, Lars; Åberg, Ingvar; Borgström, Magnus T

2018-05-09

III-V solar cells in the nanowire geometry might hold significant synthesis-cost and device-design advantages as compared to thin films and have shown impressive performance improvements in recent years. To continue this development there is a need for characterization techniques giving quick and reliable feedback for growth development. Further, characterization techniques which can improve understanding of the link between nanowire growth conditions, subsequent processing, and solar cell performance are desired. Here, we present the use of a nanoprobe system inside a scanning electron microscope to efficiently contact single nanowires and characterize them in terms of key parameters for solar cell performance. Specifically, we study single as-grown InP nanowires and use electron beam induced current characterization to understand the charge carrier collection properties, and dark current-voltage characteristics to understand the diode recombination characteristics. By correlating the single nanowire measurements to performance of fully processed nanowire array solar cells, we identify how the performance limiting parameters are related to growth and/or processing conditions. We use this understanding to achieve a more than 7-fold improvement in efficiency of our InP nanowire solar cells, grown from a different seed particle pattern than previously reported from our group. The best cell shows a certified efficiency of 15.0%; the highest reported value for a bottom-up synthesized InP nanowire solar cell. We believe the presented approach have significant potential to speed-up the development of nanowire solar cells, as well as other nanowire-based electronic/optoelectronic devices.

Cycle life test. [of secondary spacecraft cells

NASA Technical Reports Server (NTRS)

Harkness, J. D.

1977-01-01

Statistical information concerning cell performance characteristics and limitations of secondary spacecraft cells is presented. Weaknesses in cell design as well as battery weaknesses encountered in various satellite programs are reported. Emphasis is placed on improving the reliability of space batteries.

Quantifying usability: an evaluation of a diabetes mHealth system on effectiveness, efficiency, and satisfaction metrics with associated user characteristics.

PubMed

Georgsson, Mattias; Staggers, Nancy

2016-01-01

Mobile health (mHealth) systems are becoming more common for chronic disease management, but usability studies are still needed on patients' perspectives and mHealth interaction performance. This deficiency is addressed by our quantitative usability study of a mHealth diabetes system evaluating patients' task performance, satisfaction, and the relationship of these measures to user characteristics. We used metrics in the International Organization for Standardization (ISO) 9241-11 standard. After standardized training, 10 patients performed representative tasks and were assessed on individual task success, errors, efficiency (time on task), satisfaction (System Usability Scale [SUS]) and user characteristics. Tasks of exporting and correcting values proved the most difficult, had the most errors, the lowest task success rates, and consumed the longest times on task. The average SUS satisfaction score was 80.5, indicating good but not excellent system usability. Data trends showed males were more successful in task completion, and younger participants had higher performance scores. Educational level did not influence performance, but a more recent diabetes diagnosis did. Patients with more experience in information technology (IT) also had higher performance rates. Difficult task performance indicated areas for redesign. Our methods can assist others in identifying areas in need of improvement. Data about user background and IT skills also showed how user characteristics influence performance and can provide future considerations for targeted mHealth designs. Using the ISO 9241-11 usability standard, the SUS instrument for satisfaction and measuring user characteristics provided objective measures of patients' experienced usability. These could serve as an exemplar for standardized, quantitative methods for usability studies on mHealth systems. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association.

Quantifying usability: an evaluation of a diabetes mHealth system on effectiveness, efficiency, and satisfaction metrics with associated user characteristics

PubMed Central

Staggers, Nancy

2016-01-01

Objective Mobile health (mHealth) systems are becoming more common for chronic disease management, but usability studies are still needed on patients’ perspectives and mHealth interaction performance. This deficiency is addressed by our quantitative usability study of a mHealth diabetes system evaluating patients’ task performance, satisfaction, and the relationship of these measures to user characteristics. Materials and Methods We used metrics in the International Organization for Standardization (ISO) 9241-11 standard. After standardized training, 10 patients performed representative tasks and were assessed on individual task success, errors, efficiency (time on task), satisfaction (System Usability Scale [SUS]) and user characteristics. Results Tasks of exporting and correcting values proved the most difficult, had the most errors, the lowest task success rates, and consumed the longest times on task. The average SUS satisfaction score was 80.5, indicating good but not excellent system usability. Data trends showed males were more successful in task completion, and younger participants had higher performance scores. Educational level did not influence performance, but a more recent diabetes diagnosis did. Patients with more experience in information technology (IT) also had higher performance rates. Discussion Difficult task performance indicated areas for redesign. Our methods can assist others in identifying areas in need of improvement. Data about user background and IT skills also showed how user characteristics influence performance and can provide future considerations for targeted mHealth designs. Conclusion Using the ISO 9241-11 usability standard, the SUS instrument for satisfaction and measuring user characteristics provided objective measures of patients’ experienced usability. These could serve as an exemplar for standardized, quantitative methods for usability studies on mHealth systems. PMID:26377990

The Development of Si and SiGe Technologies for Microwave and Millimeter-Wave Integrated Circuits

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Alterovitz, Samuel A.; Katehi, Linda P. B.; Bhattacharya, Pallab K.

1997-01-01

Historically, microwave technology was developed by military and space agencies from around the world to satisfy their unique radar, communication, and science applications. Throughout this development phase, the sole goal was to improve the performance of the microwave circuits and components comprising the systems. For example, power amplifiers with output powers of several watts over broad bandwidths, low noise amplifiers with noise figures as low as 3 dB at 94 GHz, stable oscillators with low noise characteristics and high output power, and electronically steerable antennas were required. In addition, the reliability of the systems had to be increased because of the high monetary and human cost if a failure occurred. To achieve these goals, industry, academia and the government agencies supporting them chose to develop technologies with the greatest possibility of surpassing the state of the art performance. Thus, Si, which was already widely used for digital circuits but had material characteristics that were perceived to limit its high frequency performance, was bypassed for a progression of devices starting with GaAs Metal Semiconductor Field Effect Transistors (MESFETs) and ending with InP Pseudomorphic High Electron Mobility Transistors (PHEMTs). For each new material or device structure, the electron mobility increased, and therefore, the high frequency characteristics of the device were improved. In addition, ultra small geometry lithographic processes were developed to reduce the gate length to 0.1 pm which further increases the cutoff frequency. The resulting devices had excellent performance through the millimeter-wave spectrum.

Performance Degradation Assessment of Rolling Element Bearings using Improved Fuzzy Entropy

NASA Astrophysics Data System (ADS)

Zhu, Keheng; Jiang, Xiaohui; Chen, Liang; Li, Haolin

2017-10-01

Rolling element bearings are an important unit in the rotating machines, and their performance degradation assessment is the basis of condition-based maintenance. Targeting the non-linear dynamic characteristics of faulty signals of rolling element bearings, a bearing performance degradation assessment approach based on improved fuzzy entropy (FuzzyEn) is proposed in this paper. FuzzyEn has less dependence on data length and achieves more freedom of parameter selection and more robustness to noise. However, it neglects the global trend of the signal when calculating similarity degree of two vectors, and thus cannot reflect the running state of the rolling element bearings accurately. Based on this consideration, the algorithm of FuzzyEn is improved in this paper and the improved FuzzyEn is utilized as an indicator for bearing performance degradation evaluation. The vibration data from run-to-failure test of rolling element bearings are used to validate the proposed method. The experimental results demonstrate that, compared with the traditional kurtosis and root mean square, the proposed method can detect the incipient fault in advance and can reflect the whole performance degradation process more clearly.

Stimulus Characteristics for Vestibular Stochastic Resonance to Improve Balance Function

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrado, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

Stochastic resonance (SR) is a mechanism by which noise can enhance the response of neural systems to relevant sensory signals. Studies have shown that imperceptible stochastic vestibular electrical stimulation, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the amplitude characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standard balance task of standing on a block of foam with their eyes closed. Bipolar stochastic electrical stimulation was applied to the vestibular system using constant current stimulation through electrodes placed over the mastoid process behind the ears. Amplitude of the signals varied in the range of 0-700 microamperes. Balance performance was measured using a force plate under the foam block, and inertial motion sensors were placed on the torso and head. Balance performance with stimulation was significantly greater (10%-25%) than with no stimulation. The signal amplitude at which performance was maximized was in the range of 100-300 microamperes. Optimization of the amplitude of the stochastic signals for maximizing balance performance will have a significant impact on development of vestibular SR as a unique system to aid recovery of function in astronauts after long-duration space flight or in patients with balance disorders.

Computer-aided detection (CAD) of breast cancer on full field digital and screening film mammograms

NASA Astrophysics Data System (ADS)

Sun, Xuejun; Qian, Wei; Song, Xiaoshan; Qian, Yuyan; Song, Dansheng; Clark, Robert A.

2003-05-01

Full-field digital mammography (FFDM) as a new breast imaging modality has potential to detect more breast cancers or to detect them at smaller sizes and earlier stages compared with screening film mammography (SFM). However, its performance needs verification, and it would pose new problems for the development of CAD methods for breast cancer detection and diagnosis. Performance evaluation of CAD systems on FFDM and SFM has been conducted in this study, respectively. First, an adaptive CAD system employing a series of advanced modules has been developed on FFDM. Second, a standardization approach has been developed to make the CAD system independent of characteristics of digitizer or imaging modalities for mammography. CAD systems developed previously for SFM and developed in this study for FFDM have been evaluated on FFDM and SFM images without and with standardization, respectively, to examine the performance improvement of the CAD system developed in this study. Computerized free-response receiver operating characteristic (FROC) analysis has been adopted as performance evaluation method. Compared with previous one, the CAD system developed in this study demonstrated significantly performance improvements. However, the comparison results have shown that the performances of final CAD system in this study are not significantly different on FFDM and on SFM after standardization. It needs further study on the assessment of CAD system performance on FFDM and SFM modalities.

How Are Middle School Climate and Academic Performance Related across Schools and over Time? REL 2017-212

ERIC Educational Resources Information Center

Voight, Adam; Hanson, Thomas

2017-01-01

A growing number of educators concur that, in order to improve student academic performance, schools need to focus not only on students' academic needs but also on their social, emotional, and material needs (Piscatelli & Lee, 2011). As a result, school climate--the social, emotional, and physical characteristics of a school community (Cohen,…

Models for Improving the Delivery of Services to: Gifted Students in the Areas of Visual and Performing Arts. Research & Demonstration Series in Gifted Education.

ERIC Educational Resources Information Center

Ohio State Dept. of Education, Columbus. Div. of Special Education.

This report describes three model demonstration projects in Ohio school districts which focused on strategies for identifying students gifted in visual and performing arts and delivering hands-on arts education and appreciation experiences. Presented for each program is information on: identifying characteristics (district, location, school…

Consensus statement on essential patient characteristics in systemic treatment trials for metastatic colorectal cancer: Supported by the ARCAD Group.

PubMed

Goey, Kaitlyn K H; Sørbye, Halfdan; Glimelius, Bengt; Adams, Richard A; André, Thierry; Arnold, Dirk; Berlin, Jordan D; Bodoky, György; de Gramont, Aimery; Díaz-Rubio, Eduardo; Eng, Cathy; Falcone, Alfredo; Grothey, Axel; Heinemann, Volker; Hochster, Howard S; Kaplan, Richard S; Kopetz, Scott; Labianca, Roberto; Lieu, Christopher H; Meropol, Neal J; Price, Timothy J; Schilsky, Richard L; Schmoll, Hans-Joachim; Shacham-Shmueli, Einat; Shi, Qian; Sobrero, Alberto F; Souglakos, John; Van Cutsem, Eric; Zalcberg, John; van Oijen, Martijn G H; Punt, Cornelis J A; Koopman, Miriam

2018-06-21

Patient characteristics and stratification factors are key features influencing trial outcomes. However, there is substantial heterogeneity in reporting of patient characteristics and use of stratification factors in phase 3 trials investigating systemic treatment of metastatic colorectal cancer (mCRC). We aimed to develop a minimum set of essential baseline characteristics and stratification factors to include in such trials. We performed a modified, two-round Delphi survey among international experts with wide experience in the conduct and methodology of phase 3 trials of systemic treatment of mCRC. Thirty mCRC experts from 15 different countries completed both consensus rounds. A total of 14 patient characteristics were included in the recommended set: age, performance status, primary tumour location, primary tumour resection, prior chemotherapy, number of metastatic sites, liver-only disease, liver involvement, surgical resection of metastases, synchronous versus metachronous metastases, (K)RAS and BRAF mutation status, microsatellite instability/mismatch repair status and number of prior treatment lines. A total of five patient characteristics were considered the most relevant stratification factors: RAS/BRAF mutation status, performance status, primary tumour sidedness and liver-only disease. This survey provides a minimum set of essential baseline patient characteristics and stratification factors to include in phase 3 trials of systemic treatment of mCRC. Inclusion of these patient characteristics and strata in study protocols and final study reports will improve interpretation of trial results and facilitate cross-study comparisons. Copyright © 2018 Elsevier Ltd. All rights reserved.

How Usability Testing Resulted in Improvements to Ground Collision Software for General Aviation: Improved Ground Collision Avoidance System (IGCAS)

NASA Technical Reports Server (NTRS)

Lamarr, Michael; Chinske, Chris; Williams, Ethan; Law, Cameron; Skoog, Mark; Sorokowski, Paul

2016-01-01

The NASA improved Ground Collision Avoidance System (iGCAS) team conducted an onsite usability study at Experimental Aircraft Association (EAA) Air Venture in Oshkosh, Wisconsin from July 19 through July 26, 2015. EAA Air Venture had approximately 550,000 attendees from which the sample pool of pilots were selected. The objectives of this study were to assess the overall appropriateness and acceptability of iGCAS as a warning system for General Aviation aircraft, usability of the iGCAS displays and audio cues, test terrain avoidance characteristics, performance, functionality, pilot response time, and correlate terrain avoidance performance and pilot response time data.

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

NASA Astrophysics Data System (ADS)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance.

Development of advanced fuel cell system, phase 2

NASA Technical Reports Server (NTRS)

Handley, L. M.; Meyer, A. P.; Bell, W. F.

1973-01-01

A multiple task research and development program was performed to improve the weight, life, and performance characteristics of hydrogen-oxygen alkaline fuel cells for advanced power systems. Development and characterization of a very stable gold alloy catalyst was continued from Phase I of the program. A polymer material for fabrication of cell structural components was identified and its long term compatibility with the fuel cell environment was demonstrated in cell tests. Full scale partial cell stacks, with advanced design closed cycle evaporative coolers, were tested. The characteristics demonstrated in these tests verified the feasibility of developing the engineering model system concept into an advanced lightweight long life powerplant.

A compact roller-gear pitch-yaw joint module: Design and control issues

NASA Technical Reports Server (NTRS)

Dohring, Mark E.; Anderson, William J.; Newman, Wyatt S.; Rohn, Douglas A.

1993-01-01

Robotic systems have been proposed as a means of accomplishing assembly and maintenance tasks in space. The desirable characteristics of these systems include compact size, low mass, high load capacity, and programmable compliance to improve assembly performance. In addition, the mechanical system must transmit power in such a way as to allow high performance control of the system. Efficiency, linearity, low backlash, low torque ripple, and low friction are all desirable characteristics. This work presents a pitch-yaw joint module designed and built to address these issues. Its effectiveness as a two degree-of-freedom manipulator using natural admittance control, a method of force control, is demonstrated.

Engineering calculations for communications satellite systems planning

NASA Technical Reports Server (NTRS)

Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

1991-01-01

The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

Investigation on emission characteristics of metal-ceramic cathode applied to industrial X-ray diode.

PubMed

Xun, Ma; Jianqiang, Yuan; Hongwei, Liu; Hongtao, Li; Lingyun, Wang; Ping, Jiang

2016-06-01

The industrial x-ray diode with high impedance configuration is usually adopted to generate repetitive x-ray, but its performance would be worsened due to lower electric field on the cathode of diode when a voltage of several hundreds of kV is applied. To improve its performance, a novel metal-ceramic cathode is proposed in this paper. Key factors (width, relative permittivity of ceramic, and so on) affecting electric field distribution on triple points are analyzed by electrostatic field calculation program, so as to optimize the design of this novel cathode. Experiments are done to study the characteristics including emission current of cathode, diode voltage duration, diode mean dynamic impedance, and diode impedance drop velocity within diode power duration. The results show that metal-ceramic cathode could improve diode performance by enhancing emission current and stabling impedance; the impedance drop velocity of diode with spoke-shaped metal-ceramic cathode was reduced to -5 Ω ns(-1) within diode power duration, comparing to -15 Ω ns(-1) with metal foil cathode.

The impact of solar cell technology on planar solar array performance

NASA Technical Reports Server (NTRS)

Mills, Michael W.; Kurland, Richard M.

1989-01-01

The results of a study into the potential impact of advanced solar cell technologies on the characteristics (weight, cost, area) of typical planar solar arrays designed for low, medium and geosynchronous altitude earth orbits are discussed. The study considered planar solar array substrate designs of lightweight, rigid-panel graphite epoxy and ultra-lightweight Kapton. The study proposed to answer the following questions: Do improved cell characteristics translate into array-level weight, size and cost improvements; What is the relative importance of cell efficiency, weight and cost with respect to array-level performance; How does mission orbital environment affect array-level performance. Comparisons were made at the array level including all mechanisms, hinges, booms, and harnesses. Array designs were sized to provide 5kW of array power (not spacecraft bus power, which is system dependent but can be scaled from given values). The study used important grass roots issues such as use of the GaAs radiation damage coefficients as determined by Anspaugh. Detailed costing was prepared, including cell and cover costs, and manufacturing attrition rates for the various cell types.

Reactivity of sulfide-containing silane toward boehmite and in situ modified rubber/boehmite composites by the silane

NASA Astrophysics Data System (ADS)

Lin, Tengfei; Zhu, Lixin; Chen, Weiwei; Wu, Siwu; Guo, Baochun; Jia, Demin

2013-09-01

The silanization reaction between boehmite (BM) nanoplatelets and bis-[3-(triethoxysilyl)-propyl]-tetrasulfide (TESPT) was characterized in detail. Via such modification process, the grafted sulfide moieties on the BM endow reactivity toward rubber and substantially improved hydrophobicity for BM. Accordingly, TESPT was employed as in situ modifier for the nitrile rubber (NBR)/BM compounds to improve the mechanical properties of the reinforced vulcanizates. The effects of BM content and in situ modification on the mechanical properties, curing characteristics and morphology were investigated. BM was found to be effective in improving the mechanical performance of NBR vulcanizates. The NBR/BM composites could be further strengthened by the incorporation of TESPT. The interfacial adhesion of NBR/BM composites was obviously improved by the addition of TESPT. The substantially improved mechanical performance was correlated to the interfacial reaction and the improved dispersion of BM in rubber matrix.

Modification studies for a bridge girder of reinforced plastics.

DOT National Transportation Integrated Search

1976-01-01

Several modifications were made in the design of a glass-reinforced plastic girder in an effort to improve its load-deflection performance characteristics. The addition of lateral ties between the lower chords of adjacent girders in a trisectional st...

Effect of Cycling Skills on Bicycle Safety and Comfort Associated with Bicycle Infrastructure and Environment

DOT National Transportation Integrated Search

2017-08-31

This study seeks to improve the methodology for determining the relationship between cycling dynamic performance and roadway environment characteristics across different bicyclists' skill levels. To achieve the goal of this study, an Instrumented Pro...

Preventive care quality of Medicare Accountable Care Organizations: Associations of organizational characteristics with performance

PubMed Central

Albright, Benjamin B.; Lewis, Valerie A.; Ross, Joseph S.; Colla, Carrie H.

2015-01-01

Background Accountable Care Organizations (ACOs) are a delivery and payment model aiming to coordinate care, control costs, and improve quality. Medicare ACOs are responsible for eight measures of preventive care quality. Objectives To create composite measures of preventive care quality and examine associations of ACO characteristics with performance. Design Cross-sectional study of Medicare Shared Savings Program and Pioneer participants. We linked quality performance to descriptive data from the National Survey of ACOs. We created composite measures using exploratory factor analysis, and used regression to assess associations with organizational characteristics. Results Of 252 eligible ACOs, 246 reported on preventive care quality, 177 of which completed the survey (response rate=72%). In their first year, ACOs lagged behind PPO performance on the majority of comparable measures. We identified two underlying factors among eight measures and created composites for each: disease prevention, driven by vaccines and cancer screenings, and wellness screening, driven by annual health screenings. Participation in the Advanced Payment Model, having fewer specialists, and having more Medicare ACO beneficiaries per primary care provider were associated with significantly better performance on both composites. Better performance on disease prevention was also associated with inclusion of a hospital, greater electronic health record capabilities, a larger primary care workforce, and fewer minority beneficiaries. Conclusions ACO preventive care quality performance is related to provider composition and benefitted by upfront investment. Vaccine and cancer screening quality performance is more dependent on organizational structure and characteristics than performance on annual wellness screenings, likely due to greater complexity in eligibility determination and service administration. PMID:26759974

Preventive Care Quality of Medicare Accountable Care Organizations: Associations of Organizational Characteristics With Performance.

PubMed

Albright, Benjamin B; Lewis, Valerie A; Ross, Joseph S; Colla, Carrie H

2016-03-01

Accountable Care Organizations (ACOs) are a delivery and payment model aiming to coordinate care, control costs, and improve quality. Medicare ACOs are responsible for 8 measures of preventive care quality. To create composite measures of preventive care quality and examine associations of ACO characteristics with performance. This is a cross-sectional study of Medicare Shared Savings Program and Pioneer participants. We linked quality performance to descriptive data from the National Survey of ACOs. We created composite measures using exploratory factor analysis, and used regression to assess associations with organizational characteristics. Of 252 eligible ACOs, 246 reported on preventive care quality, 177 of which completed the survey (response rate=72%). In their first year, ACOs lagged behind PPO performance on the majority of comparable measures. We identified 2 underlying factors among 8 measures and created composites for each: disease prevention, driven by vaccines and cancer screenings, and wellness screening, driven by annual health screenings. Participation in the Advanced Payment Model, having fewer specialists, and having more Medicare ACO beneficiaries per primary care provider were associated with significantly better performance on both composites. Better performance on disease prevention was also associated with inclusion of a hospital, greater electronic health record capabilities, a larger primary care workforce, and fewer minority beneficiaries. ACO preventive care quality performance is related to provider composition and benefitted by upfront investment. Vaccine and cancer screening quality performance is more dependent on organizational structure and characteristics than performance on annual wellness screenings, likely due to greater complexity in eligibility determination and service administration.

Performing under pressure: Exploring the psychological state underlying clutch performance in sport.

PubMed

Swann, Christian; Crust, Lee; Jackman, Patricia; Vella, Stewart A; Allen, Mark S; Keegan, Richard

2017-12-01

Clutch performance is improved performance under pressure. However, little research has examined the psychological state experienced by athletes in these situations. Therefore, this study qualitatively examined the subjective experience underlying clutch performance across a range of sports (e.g., team, individual) and standards (Olympic to recreational athletes). Sixteen athletes (M age  = 27.08 years; SD = 6.48) took part in in-depth, semi-structured interviews primarily after an exceptional performance (M = 4.38 days later; SD = 3.14). Data were analysed inductively and thematically. Clutch states involved 12 characteristics, including heightened and deliberate concentration, intense effort, and heightened awareness, which distinguished the experience of clutch from other optimal psychological states such as flow. Other characteristics, such as perceptions of control, were also reported and supported previous experimental research on clutch. These findings present in-depth qualitative insights into the psychological state underlying clutch performance, and are discussed in relation to the existing literature on optimal psychological states in sport.

Thermal-Performance Instability in Piezoresistive Sensors: Inducement and Improvement

PubMed Central

Liu, Yan; Wang, Hai; Zhao, Wei; Qin, Hongbo; Fang, Xuan

2016-01-01

The field of piezoresistive sensors has been undergoing a significant revolution in terms of design methodology, material technology and micromachining process. However, the temperature dependence of sensor characteristics remains a hurdle to cross. This review focuses on the issues in thermal-performance instability of piezoresistive sensors. Based on the operation fundamental, inducements to the instability are investigated in detail and correspondingly available ameliorative methods are presented. Pros and cons of each improvement approach are also summarized. Though several schemes have been proposed and put into reality with favorable achievements, the schemes featuring simple implementation and excellent compatibility with existing techniques are still emergently demanded to construct a piezoresistive sensor with excellent comprehensive performance. PMID:27886125

Effect of oblique channel on discharge characteristics of 200-W Hall thruster

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Peng, Wuji; Sun, Hezhi; Xu, Yu; Wei, Liqiu; Li, Hong; Zeng, Ming; Wang, Fufeng; Yu, Daren

2017-02-01

In an experiment involving a 200-W Hall thruster, partial ionization occurs in the plume area because of the extrapolation of the magnetic field. To improve the thruster performance, the concept of an oblique channel is proposed for improving the ionization degree in the plume area. Calculations performed using a Particle-in-cell (PIC) simulator and the experimental results both show that an oblique channel structure can reduce the wall loss. Compared with a straight channel under similar conditions of the discharge voltage and current, the ionization degree in the plume area, thrust, specific impulse, propellant utilization, and anode efficiency are improved by ˜20%. The oblique channel is an important design consideration for improving the partial ionization of the plume area in the thruster.

Microstructures and Dry Sliding Wear Resistance of the Laser Ceramics Composite Coating on Pure Ti

NASA Astrophysics Data System (ADS)

Liu, Peng; Zhang, Yuanbin; Luo, Hui; Huo, Yushuang

2012-06-01

In this study, Al-Ti-Co was used to improve the surface performance of pure Ti. Laser cladding is an important surface modification technique, which can be used to improve the surface performance of pure Ti. Laser cladding of the Al-Ti-Co + TiB2 pre-placed powders on pure Ti can form ceramics reinforced the composite coating, which improved the wear resistance of the substrate. Characteristics of the composite coating were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness and wear tests. And the laser-cladded coating can also have major dilution from the substrate. Due to the action of the fine grain strengthening and the phase constituent, the wear resistance and microhardness of pure Ti surface were greatly improved.

Improved Wide Operating Temperature Range of Li-Ion Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Bugga, Ratnakumar V.

2013-01-01

Future NASA missions aimed at exploring the Moon, Mars, and the outer planets require rechargeable batteries that can operate over a wide temperature range (-60 to +60 C) to satisfy the requirements of various applications including landers, rovers, penetrators, CEV, CLV, etc. This work addresses the need for robust rechargeable batteries that can operate well over a wide temperature range. The Department of Energy (DoE) has identified a number of technical barriers associated with the development of Liion rechargeable batteries for PHEVs. For this reason, DoE has interest in the development of advanced electrolytes that will improve performance over a wide range of temperatures, and lead to long life characteristics (5,000 cycles over a 10-year life span). There is also interest in improving the high-voltage stability of these candidate electrolyte systems to enable the operation of up to 5 V with high specific energy cathode materials. Currently, the state-of-the-art lithium-ion system has been demonstrated to operate over a wide range of temperatures (-40 to +40 C); however, the rate capability at the lower temperatures is very poor. In addition, the low-temperature performance typically deteriorates rapidly upon being exposed to high temperatures. A number of electrolyte formulations were developed that incorporate the use of electrolyte additives to improve the high-temperature resilience, low-temperature power capability, and life characteristics of methyl propionate (MP)-based electrolyte solutions. These electrolyte additives include mono-fluoroethylene carbonate (FEC), lithium oxalate, vinylene carbonate (VC), and lithium bis(oxalate borate) (LiBOB), which have previously been shown to result in improved high-temperature resilience of all carbonate-based electrolytes. These MP-based electrolytes with additives have been shown to have improved performance in experiments with MCMB-LiNiCoAlO2 cells.

Manufacture of conical springs with elastic medium technology improvement

NASA Astrophysics Data System (ADS)

Kurguzov, S. A.; Mikhailova, U. V.; Kalugina, O. B.

2018-01-01

This article considers the manufacturing technology improvement by using an elastic medium in the stamping tool forming space to improve the conical springs performance characteristics and reduce the costs of their production. Estimation technique of disk spring operational properties is developed by mathematical modeling of the compression process during the operation of a spring. A technique for optimizing the design parameters of a conical spring is developed, which ensures a minimum voltage value when operated in the edge of the spring opening.

Protection of Conductive and Non-conductive Advanced Polymer-based Paints from Highly Aggressive Oxidative Environments

NASA Technical Reports Server (NTRS)

Gudimenko, Y.; Ng, R.; Iskanderova, Z.; Kleiman, J.; Grigorevsky, A.; Kiseleva, L.; Finckenor, M.; Edwards, D.

2005-01-01

Research has been continued to further improve the space durability of conductive and non-conductive polymer-based paints and of conductive thermal control paints for space applications. Efforts have been made to enhance the space durability and stability of functional Characteristics in ground-based space environment imitating conditions, using specially developed surface modification treatment. The results of surface modification of new conductive paints, including the ground-based testing in aggressive oxidative environments, such as atomic oxygen/UV and oxygen plasma, and performance evaluation are presented. Functional properties and performance characteristics, such as thermal optical properties (differential solar absorptance and thermal emittance representing the thermal optical performance of thermal control paints) and surface resistivity characteristics of pristine, surface modified, and tested materials were verified. Extensive surface analysis studies have been performed using complementary surface analyses including SEM/EDS and XPS. Test results revealed that the successfully treated materials exhibit reduced mass loss and no surface morphology change, thus indicating good protection from the severe oxidative environment. It was demonstrated that the developed surface modification treatment could be applied successfully to charge dissipative and conductive paints.

High performance low voltage organic field effect transistors on plastic substrate for amplifier circuits

NASA Astrophysics Data System (ADS)

Houin, G.; Duez, F.; Garcia, L.; Cantatore, E.; Torricelli, F.; Hirsch, L.; Belot, D.; Pellet, C.; Abbas, M.

2016-09-01

The high performance air stable organic semiconductor small molecule dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) was chosen as active layer for field effect transistors built to realize flexible amplifier circuits. Initial device on rigid Si/SiO2 substrate showed appreciable performance with hysteresis-free characteristics. A number of approaches were applied to simplify the process, improve device performance and decrease the operating voltage: they include an oxide interfacial layer to decrease contact resistance; a polymer passivation layer to optimize semiconductor/dielectric interface and an anodized high-k oxide as dielectric layer for low voltage operation. The devices fabricated on plastic substrate yielded excellent electrical characteristics, showing mobility of 1.6 cm2/Vs, lack of hysteresis, operation below 5 V and on/off current ratio above 105. An OFET model based on variable ranging hopping theory was used to extract the relevant parameters from the transfer and output characteristics, which enabled us to simulate our devices achieving reasonable agreement with the measurements

Effects of the F4TCNQ-Doped Pentacene Interlayers on Performance Improvement of Top-Contact Pentacene-Based Organic Thin-Film Transistors

PubMed Central

Fan, Ching-Lin; Lin, Wei-Chun; Chang, Hsiang-Sheng; Lin, Yu-Zuo; Huang, Bohr-Ran

2016-01-01

In this paper, the top-contact (TC) pentacene-based organic thin-film transistor (OTFT) with a tetrafluorotetracyanoquinodimethane (F4TCNQ)-doped pentacene interlayer between the source/drain electrodes and the pentacene channel layer were fabricated using the co-evaporation method. Compared with a pentacene-based OTFT without an interlayer, OTFTs with an F4TCNQ:pentacene ratio of 1:1 showed considerably improved electrical characteristics. In addition, the dependence of the OTFT performance on the thickness of the F4TCNQ-doped pentacene interlayer is weaker than that on a Teflon interlayer. Therefore, a molecular doping-type F4TCNQ-doped pentacene interlayer is a suitable carrier injection layer that can improve the TC-OTFT performance and facilitate obtaining a stable process window. PMID:28787845

Thin Film Electrodes with an Integral Current Collection Grid for Use with Solid Electrolytes

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Kisor, A.; Williams, R. M.; Jeffries-Nakamura, B.; O'Connor, D.

1994-01-01

Thin film, high performance electrodes which can operate in high temperature environments are necessary for many devices which use a solid electrolyte. Electrodes of rhodium-tungsten alloy have been deposited on solid electrolyte using photolytic chemical vapor deposition (PCVD). A technique for depositing electrodes and current collection grids simultaneously has been developed using the prenucleation characteristics of PCVD. This technique makes it possible to fabricate electrodes which allow vapor transport through the thin (<1 (micro)m) portions of the electrode while integral thick grid lines improve the electronic conductivity of the electrode, thus improving overall performance.

Electrolytes for Use in High Energy Lithium-Ion Batteries with Wide Operating Temperature Range

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

2011-01-01

Objectives of this work are: (1) Develop advanced Li -ion electrolytes that enable cell operation over a wide temperature range (i.e., -30 to +60C). (2) Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (3) Improve the high voltage stability of these candidate electrolytes systems to enable operation up to 5V with high specific energy cathode materials. (4) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (5) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

Social-aware data dissemination in opportunistic mobile social networks

NASA Astrophysics Data System (ADS)

Yang, Yibo; Zhao, Honglin; Ma, Jinlong; Han, Xiaowei

Opportunistic Mobile Social Networks (OMSNs), formed by mobile users with social relationships and characteristics, enhance spontaneous communication among users that opportunistically encounter each other. Such networks can be exploited to improve the performance of data forwarding. Discovering optimal relay nodes is one of the important issues for efficient data propagation in OMSNs. Although traditional centrality definitions to identify the nodes features in network, they cannot identify effectively the influential nodes for data dissemination in OMSNs. Existing protocols take advantage of spatial contact frequency and social characteristics to enhance transmission performance. However, existing protocols have not fully exploited the benefits of the relations and the effects between geographical information, social features and user interests. In this paper, we first evaluate these three characteristics of users and design a routing protocol called Geo-Social-Interest (GSI) protocol to select optimal relay nodes. We compare the performance of GSI using real INFOCOM06 data sets. The experiment results demonstrate that GSI overperforms the other protocols with highest data delivery ratio and low communication overhead.

Cross spectral, active and passive approach to face recognition for improved performance

NASA Astrophysics Data System (ADS)

Grudzien, A.; Kowalski, M.; Szustakowski, M.

2017-08-01

Biometrics is a technique for automatic recognition of a person based on physiological or behavior characteristics. Since the characteristics used are unique, biometrics can create a direct link between a person and identity, based on variety of characteristics. The human face is one of the most important biometric modalities for automatic authentication. The most popular method of face recognition which relies on processing of visual information seems to be imperfect. Thermal infrared imagery may be a promising alternative or complement to visible range imaging due to its several reasons. This paper presents an approach of combining both methods.

Synthesis of correlation filters: a generalized space-domain approach for improved filter characteristics

NASA Astrophysics Data System (ADS)

Sudharsanan, Subramania I.; Mahalanobis, Abhijit; Sundareshan, Malur K.

1990-12-01

Discrete frequency domain design of Minimum Average Correlation Energy filters for optical pattern recognition introduces an implementational limitation of circular correlation. An alternative methodology which uses space domain computations to overcome this problem is presented. The technique is generalized to construct an improved synthetic discriminant function which satisfies the conflicting requirements of reduced noise variance and sharp correlation peaks to facilitate ease of detection. A quantitative evaluation of the performance characteristics of the new filter is conducted and is shown to compare favorably with the well known Minimum Variance Synthetic Discriminant Function and the space domain Minimum Average Correlation Energy filter, which are special cases of the present design.

Flow Quality Measurements in an Aerodynamic Model of NASA Lewis' Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Canacci, Victor A.; Gonsalez, Jose C.

1999-01-01

As part of an ongoing effort to improve the aerodynamic flow characteristics of the Icing Research Tunnel (IRT), a modular scale model of the facility was fabricated. This 1/10th-scale model was used to gain further understanding of the flow characteristics in the IRT. The model was outfitted with instrumentation and data acquisition systems to determine pressures, velocities, and flow angles in the settling chamber and test section. Parametric flow quality studies involving the insertion and removal of a model of the IRT's distinctive heat exchanger (cooler) and/or of a honeycomb in the settling chamber were performed. These experiments illustrate the resulting improvement or degradation in flow quality.

Defect healing at room temperature in pentacene thin films and improved transistor performance

NASA Astrophysics Data System (ADS)

Kalb, Wolfgang L.; Meier, Fabian; Mattenberger, Kurt; Batlogg, Bertram

2007-11-01

We report on a healing of defects at room temperature in the organic semiconductor pentacene. This peculiar effect is a direct consequence of the weak intermolecular interaction which is characteristic of organic semiconductors. Pentacene thin-film transistors were fabricated and characterized by in situ gated four-terminal measurements. Under high vacuum conditions (base pressure of order 10-8mbar ), the device performance is found to improve with time. The effective field-effect mobility increases by as much as a factor of 2 and mobilities up to 0.45cm2/Vs were achieved. In addition, the contact resistance decreases by more than an order of magnitude and there is a significant reduction in current hysteresis. Oxygen and nitrogen exposure as well as annealing experiments show the improvement of the electronic parameters to be driven by a thermally promoted process and not by chemical doping. In order to extract the spectral density of trap states from the transistor characteristics, we have implemented a powerful scheme which allows for a calculation of the trap densities with high accuracy in a straightforward fashion. We show the performance improvement to be due to a reduction in the density of shallow traps ⩽0.15eV from the valence band edge, while the energetically deeper traps are essentially unaffected. This work contributes to an understanding of the shallow traps in organic semiconductors and identifies structural point defects within the grains of the polycrystalline thin films as a major cause.

Paravertebral Spinal Injection for the Treatment of Patients with Degenerative Facet Osteoarthropathy: Evidence of Motor Performance Improvements based on Objective Assessments

PubMed Central

Toosizadeh, Nima; Harati, Homayoon; Yen, Tzu-Chuan; Fastje, Cindy; Mohler, Jane; Najafi, Bijan; Dohm, Michael

2016-01-01

Background This study examined short- and long-term improvements in motor performance, quantified using wearable sensors, in response to facet spine injection in degenerative facet osteoarthropathy patients. Methods Adults with confirmed degenerative facet osteoarthropathy were recruited and were treated with medial or intermediate branch block injection. Self-report pain, health condition, and disability (Oswestry), as well as objective motor performance measures (gait, balance, and timed-up-and-go) were obtained in five sessions: pre-surgery (baseline), immediately after the injection, one-month, three-month, and 12-month follow-ups. Baseline motor performance parameters were compared with 10 healthy controls. Findings Thirty patients (age=50(14) years) and 10 controls (age=46(15) years) were recruited. All motor performance parameters were significantly different between groups. Results showed that average pain and Oswestry scores improved by 51% and 24%, respectively among patients, only one month after injection. Similarly, improvement in motor performance was most noticeable in one-month post-injection measurements; most improvements were observed in gait speed (14% normal walking, P<0.02), hip sway within balance tests (63% eyes-open P<0.01), and turning velocity within the timed-up-and-go test (28%, P<0.02). Better baseline motor performance led to better outcomes in terms of pain relief; baseline turning velocity was 18% faster among the responsive compared to the non-responsive patients. Interpretations Spinal injection can temporarily (one to three months) improve motor performance in degenerative facet osteoarthropathy patients. Successful pain relief in response to treatment is independent of demographic characteristics and initial pain but dependent on baseline motor performance. Immediate self-reported pain relief is unrelated to magnitude of gradual improvement in motor performance. PMID:27744005

Microchannel Plate Imaging Detectors for the Ultraviolet

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

1992-01-01

There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

Experimental Aerodynamic Characteristics of a Joined-wing Research Aircraft Configuration

NASA Technical Reports Server (NTRS)

Smith, Stephen C.; Stonum, Ronald K.

1989-01-01

A wind-tunnel test was conducted at Ames Research Center to measure the aerodynamic characteristics of a joined-wing research aircraft (JWRA). This aircraft was designed to utilize the fuselage and engines of the existing NASA AD-1 aircraft. The JWRA was designed to have removable outer wing panels to represent three different configurations with the interwing joint at different fractions of the wing span. A one-sixth-scale wind-tunnel model of all three configurations of the JWRA was tested in the Ames 12-Foot Pressure Wind Tunnel to measure aerodynamic performance, stability, and control characteristics. The results of these tests are presented. Longitudinal and lateral-directional characteristics were measured over an angle of attack range of -7 to 14 deg and over an angle of sideslip range of -5 to +2.5 deg at a Mach number of 0.35 and a Reynolds number of 2.2x10(6)/ft. Various combinations of deflected control surfaces were tested to measure the effectiveness and impact on stability of several control surface arrangements. In addition, the effects on stall and post-stall aerodynamic characteristics from small leading-edge devices called vortilons were measured. The results of these tests indicate that the JWRA had very good aerodynamic performance and acceptable stability and control throughout its flight envelope. The vortilons produced a profound improvement in the stall and post-stall characteristics with no measurable effects on cruise performance.

Intellectual Capital: Comparison and Contrast.

ERIC Educational Resources Information Center

Madsen, Susan R.

2001-01-01

Suggests that one of the most important keys for improving individual and organizational performance is in developing and strengthening intellectual capital (IC) and explores the similarities and differences between the concepts of intellectual capital, human capital, and knowledge management. Presents four IC characteristics and addresses the…

Dobson ozone spectrophotometer modification.

NASA Technical Reports Server (NTRS)

Komhyr, W. D.; Grass, R. D.

1972-01-01

Description of a modified version of the Dobson ozone spectrophotometer in which several outdated electronic design features have been replaced by circuitry embodying more modern design concepts. The resulting improvement in performance characteristics has been obtained without changing the principle of operation of the original instrument.

Improved high-intensity microwave discharge lamp for atomic resonance absorption and fluorescence spectrometry.

PubMed

Lifshitz, A; Skinner, G B; Wood, D R

1978-09-01

An unusually good combination of high intensity and narrow line has been achieved in a microwave discharge lamp by placing the optical window in the center of the microwave cavity. Construction details and performance characteristics are described.

Assessment of n-pentanol/Calophyllum inophyllum/diesel blends on the performance, emission, and combustion characteristics of a constant-speed variable compression ratio direct injection diesel engine.

PubMed

Ramakrishnan, Purnachandran; Kasimani, Ramesh; Peer, Mohamed Shameer; Rajamohan, Sakthivel

2018-05-01

Alcohol is used as an additive for a long time with the petroleum-based fuels. In this study, the higher alcohol, n-pentanol, was used as an additive to Calophyllum inophyllum (CI) biodiesel/diesel blends at 10, 15, and 20% by volume. In all blends, the ratio of CI was maintained at 20% by volume. The engine characteristics of the pentanol fuel blends were compared with the diesel and CI20 (Calophyllum inophyllum 20% and diesel 80%) biodiesel blend. The nitrogen oxide (NO) emission of the pentanol fuel blends showed an increased value than CI20 and neat diesel fuel. The carbon dioxide (CO 2 ) also increased with increase in pentanol addition with the fuel blends than CI20 fuel blend and diesel. The carbon monoxide (CO) and hydrocarbon (HC) emissions were decreased with increase in pentanol proportion in the blend than the CI20 fuel and diesel. The smoke emission was reduced and the combustion characteristics of the engine were also improved by using pentanol blended fuels. From this investigation, it is suggested that 20% pentanol addition with the biodiesel/diesel fuel is suitable for improved performance and combustion characteristics of a diesel engine without any engine modifications, whereas CO 2 and NO emissions increased with addition of pentanol due to effective combustion.

Can soft biometric traits assist user recognition?

NASA Astrophysics Data System (ADS)

Jain, Anil K.; Dass, Sarat C.; Nandakumar, Karthik

2004-08-01

Biometrics is rapidly gaining acceptance as the technology that can meet the ever increasing need for security in critical applications. Biometric systems automatically recognize individuals based on their physiological and behavioral characteristics. Hence, the fundamental requirement of any biometric recognition system is a human trait having several desirable properties like universality, distinctiveness, permanence, collectability, acceptability, and resistance to circumvention. However, a human characteristic that possesses all these properties has not yet been identified. As a result, none of the existing biometric systems provide perfect recognition and there is a scope for improving the performance of these systems. Although characteristics like gender, ethnicity, age, height, weight and eye color are not unique and reliable, they provide some information about the user. We refer to these characteristics as "soft" biometric traits and argue that these traits can complement the identity information provided by the primary biometric identifiers like fingerprint and face. This paper presents the motivation for utilizing soft biometric information and analyzes how the soft biometric traits can be automatically extracted and incorporated in the decision making process of the primary biometric system. Preliminary experiments were conducted on a fingerprint database of 160 users by synthetically generating soft biometric traits like gender, ethnicity, and height based on known statistics. The results show that the use of additional soft biometric user information significantly improves (approximately 6%) the recognition performance of the fingerprint biometric system.

Paper-like electronic displays: Large-area rubber-stamped plastic sheets of electronics and microencapsulated electrophoretic inks

PubMed Central

Rogers, John A.; Bao, Zhenan; Baldwin, Kirk; Dodabalapur, Ananth; Crone, Brian; Raju, V. R.; Kuck, Valerie; Katz, Howard; Amundson, Karl; Ewing, Jay; Drzaic, Paul

2001-01-01

Electronic systems that use rugged lightweight plastics potentially offer attractive characteristics (low-cost processing, mechanical flexibility, large area coverage, etc.) that are not easily achieved with established silicon technologies. This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane circuits (256 transistors) for large (≈5 × 5-inch) mechanically flexible sheets of electronic paper, an emerging type of display. The success of this effort relies on new or improved processing techniques and materials for plastic electronics, including methods for (i) rubber stamping (microcontact printing) high-resolution (≈1 μm) circuits with low levels of defects and good registration over large areas, (ii) achieving low leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing high-performance organic transistors with bottom contact geometries, (iv) encapsulating these transistors, (v) depositing, in a repeatable way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature (≈100°C) annealing to increase the on/off ratios of the transistors and to improve the uniformity of their characteristics. The sophistication and flexibility of the patterning procedures, high level of integration on plastic substrates, large area coverage, and good performance of the transistors are all important features of this work. We successfully integrate these circuits with microencapsulated electrophoretic “inks” to form sheets of electronic paper. PMID:11320233

Recent advances in Li/SO2 battery technology

NASA Astrophysics Data System (ADS)

Ralston, R. E.

The areas of improvement discussed are related to cell closure-hermetic seals, improved glass-to-metal seals, and lithium-limited cell design. Attention is given to the design of a Li/SO2 cell which can safely withstand discharge below zero volts into voltage reversal. The design characteristics of an unbalanced cell, the new lithium-limited or balanced cell, and a high rate unbalanced design are compared in a table for the 'D' size cell. It is concluded that the improvements in cell closure, glass seal stability, and cell balance have resulted in storability, reliability, and abuse resistance characteristics which make the performance of today's Li/SO2 battery without equal among competitive primary batteries. However, the Li/SO2 cell must not be used in applications where extreme electrical or environmental conditions can push the system beyond its recommended limits.

Depressive and anxiety disorders on-the-job: the importance of job characteristics for good work functioning in persons with depressive and anxiety disorders.

PubMed

Plaisier, Inger; de Graaf, Ron; de Bruijn, Jeanne; Smit, Johannes; van Dyck, Richard; Beekman, Aartjan; Penninx, Brenda

2012-12-30

This study examines the importance of job characteristics on absence and on-the-job performance in a large group of employees with diagnosed depressive and anxiety disorders. In a sample of 1522 employees (1129 persons with and 393 persons without psychopathology) participating in Netherlands Study of Depression and Anxiety (NESDA, n=2981) we examined associations between job characteristics and work functioning (absenteeism and work performance) in multinominal logistic regression models. Job characteristics were working hours, psychosocial working conditions and occupational status. As expected, depressed and anxious patients were at significantly elevated risk for absenteeism and poor work performance. In analyses adjusted for psychopathology, absenteeism and poor performance were significantly lower among persons reporting high job support, high job control, less working hours, self-employed and high skilled jobs. Associations were comparable between persons with and without psychopathology. High job support, high job control and reduced working hours were partially related to work functioning in both workers with- and without-psychopathology. Since depressed and anxious employees are at a substantially increased risk for absenteeism and poor work performance, strategies that improve job support and feelings of control at work may be especially helpful to prevent poor work functioning in this at-risk group of employees. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Sustainability in the AAP Bronchiolitis Quality Improvement Project.

PubMed

Shadman, Kristin A; Ralston, Shawn L; Garber, Matthew D; Eickhoff, Jens; Mussman, Grant M; Walley, Susan C; Rice-Conboy, Elizabeth; Coller, Ryan J

2017-11-01

Adherence to American Academy of Pediatrics (AAP) bronchiolitis clinical practice guideline recommendations improved significantly through the AAP's multiinstitutional collaborative, the Bronchiolitis Quality Improvement Project (BQIP). We assessed sustainability of improvements at participating institutions for 1 year following completion of the collaborative. Twenty-one multidisciplinary hospital-based teams provided monthly data for key inpatient bronchiolitis measures during baseline and intervention bronchiolitis seasons. Nine sites provided data in the season following completion of the collaborative. Encounters included children younger than 24 months who were hospitalized for bronchiolitis without comorbid chronic illness, prematurity, or intensive care. Changes between baseline-, intervention-, and sustainability-season data were assessed using generalized linear mixed-effects models with site-specific random effects. Differences between hospital characteristics, baseline performance, and initial improvement between sites that did and did not participate in the sustainability season were compared. A total of 2275 discharges were reviewed, comprising 995 baseline, 877 intervention, and 403 sustainability- season encounters. Improvements in all key bronchiolitis quality measures achieved during the intervention season were maintained during the sustainability season, and orders for intermittent pulse oximetry increased from 40.6% (95% confidence interval [CI], 22.8-61.1) to 79.2% (95% CI, 58.0- 91.3). Sites that did and did not participate in the sustainability season had similar characteristics. BQIP participating sites maintained improvements in key bronchiolitis quality measures for 1 year following the project's completion. This approach, which provided an evidence-based best-practice toolkit while building the quality-improvement capacity of local interdisciplinary teams, may support performance gains that persist beyond the active phase of the collaborative. © 2017 Society of Hospital Medicine

Heat Transfer and Friction Characteristics of Artificially Roughened Duct used for Solar Air Heaters—a Review

NASA Astrophysics Data System (ADS)

Kumar, Khushmeet; Prajapati, D. R.; Samir, Sushant

2018-02-01

Solar air heater uses the energy coming from the sun to heat the air. The conversion rate of solar energy to heat depends upon the efficiency of the solar air heater and this efficiency can be increased by the use of artificial roughness on the surface of absorber plate. Various studies were carried out to analyse the effect of different roughness geometries on heat transfer and friction factor characteristics. The thermo-hydraulic performance of solar air heater can be evaluated in terms of effective efficiency, thermo-hydraulic performance parameter and exergetic efficiency. In this study various geometries used for artificial roughness and to improve the performance of solar air heaters were studied. Also correlations developed by various researchers are presented in this paper.

HIIT enhances endurance performance and aerobic characteristics more than high-volume training in trained rowers.

PubMed

Ní Chéilleachair, Niamh J; Harrison, Andrew J; Warrington, Giles D

2017-06-01

This study compared the effects of long slow distance training (LSD) with high-intensity interval training (HIIT) in rowers. Nineteen well-trained rowers performed three tests before and after an 8-week training intervention: (1) 2000 m time trial; (2) seven-stage incremental step test to determine maximum oxygen uptake ([Formula: see text]O 2max ), power output at [Formula: see text]O 2max (W[Formula: see text]O 2max ), peak power output (PPO), rowing economy and blood lactate indices and (3) seven-stroke power-output test to determine maximal power output (W max ) and force (F max ). After baseline testing, participants were randomly assigned either to a HIIT or LSD group. The LSD comprised 10 weekly aerobic sessions. The HIIT also comprised 10 weekly sessions: 8 aerobic and 2 HIIT. The HIIT sessions comprised 6-8 × 2.5 min intervals at 100% PPO with recovery time based on heart rate (HR) returning to 70% HR max . Results demonstrated that the HIIT produced greater improvement in 2000 m time trial performance than the LSD (effect size (ES) = 0.25). Moreover, the HIIT produced greater improvements in [Formula: see text]O 2max (ES = 0.95, P = 0.035) and power output at lactate threshold (W LT ) (ES = 1.15, P = 0.008). Eight weeks of HIIT performed at 100% PPO is more effective than LSD in improving performance and aerobic characteristics in well-trained rowers.

Characteristics of a Refrigeration Cycle Using a Zeotropic Refrigerant Mixture with a Temperature Glide Shift Heat Exchanger

NASA Astrophysics Data System (ADS)

Endoh, Kazuhiro; Matsushima, Hiroaki; Nonaka, Masayuki

HFC zeotropic refrigerant mixture R-407C is one of the promising alternatives for HCFC-22. We have found that the coefficient of performance (COP) of the refrigeration cycle using R-407C is improved by installing a temperature glide shift heat exchanger (TGSX) which takes advantage of zeotropic characteristics to an air-conditioner. We obtained the characteristics of a refrigeration cycle of experimental apparatus with comparison to those of a fundamental refrigeration cycle based on the refrigerant thermodynamic properties. We concluded that the COP improvement ratio of experimental apparatus with the TGSX to that without the TGSX is greater than that ratio which is calculated from the fundamental refrigeration cycle. This proved to be caused by the pressure loss of low pressure side which is not taken into account in the fundamental refrigeration cycle.

Effects of Two Physical Training Paradigms on Biological and Cognitive Characteristics of Airmen: Lessons Learned

DTIC Science & Technology

2017-06-07

a 9- week physical training program, tests of physical endurance and strength , body composition analyses, biomarker collections, and cognitive tests...BDNF results to improving training , a new laboratory capability within RHCP was needed, coupled with an initial operational pilot test of that...traditional AF fitness training and that the improvements in cognitive performance would be correlated with changes in BDNF levels. Specifically, the

Improving Aerosol and Visibility Forecasting Capabilities Using Current and Future Generations of Satellite Observations

DTIC Science & Technology

2012-09-30

improving forecast performance over cloudy regions using the Ozone Monitoring Instrument (OMI) Aerosol Index; and 2) preparing for the post-MODIS...meteorological fields, the International Geosphere-Biosphere Programme (IGBP) SW and LW surface characteristics, and an ozone climatology are used as...The primary impact of CALIOP assimilation on the model is the redistribution of mass toward the boundary layer from the free troposphere . For high

Estimation of power lithium-ion battery SOC based on fuzzy optimal decision

NASA Astrophysics Data System (ADS)

He, Dongmei; Hou, Enguang; Qiao, Xin; Liu, Guangmin

2018-06-01

In order to improve vehicle performance and safety, need to accurately estimate the power lithium battery state of charge (SOC), analyzing the common SOC estimation methods, according to the characteristics open circuit voltage and Kalman filter algorithm, using T - S fuzzy model, established a lithium battery SOC estimation method based on the fuzzy optimal decision. Simulation results show that the battery model accuracy can be improved.

Kyphectomy in meningomyelocele children: surgical technique, risk analysis, and improvement of kyphosis.

PubMed

de Amoreira Gepp, Ricardo; Quiroga, Marco Rolando Sainz; Gomes, Cícero Ricardo; de Araújo, Hugo José

2013-07-01

Kyphosis is a major complication of spina bifida, causing skin ulcers and osteomyelitis. This study examined the clinical and surgical characteristics of eight patients who underwent surgery, as well as improvement of their postoperative kyphosis angulations. The authors reviewed eight cases submitted to surgery between 2006 and 2010. Surgical intervention was indicated for osteomyelitis and recurrent ulcers at the curvature apex. Osteotomies and spine stabilization were performed. The patients' clinical characteristics were analyzed, as were the surgical techniques employed, variables of surgical complications, and angle range of the kyphosis deformity postcorrection. There were no deaths. The average age at the time of surgery was 11 years old. The level of neurological injury was T10 in four patients and T12 in four. Average amount of bleeding during surgery was 1,442 ml, (range, 340 to 3,200 ml). Improvement of kyphosis angle was evident in all patients. The average difference between preoperative and postoperative kyphosis angle was 63.2. Surgery performed by a multidisciplinary team minimizes risks. Despite the high number of complications published in the literature, the results found in this study were excellent with regards to improving kyphosis angle, as well as facilitating rehabilitation and daily care of children.

A new silica-infiltrated Y-TZP obtained by the sol-gel method.

PubMed

Campos, T M B; Ramos, N C; Machado, J P B; Bottino, M A; Souza, R O A; Melo, R M

2016-05-01

The aim of this study was to evaluate silica infiltration into dental zirconia (VITA In-Ceram 2000 YZ, Vita Zahnfabrik) and its effects on zirconia's surface characteristics, structural homogeneity and bonding to a resin cement. Infiltration was performed by immersion of the pre-sintered zirconia specimens in silica sols for five days (ZIn). Negative (pure zirconia specimens, ZCon-) and positive controls (specimens kept in water for 5 days, ZCon+) were also performed. After sintering, the groups were evaluated by X-ray diffraction (XRD), grazing angle X-ray diffraction (DRXR), scanning electron microscopy (SEM), contact angle measurements, optical profilometry, biaxial flexural test and shear bonding test. Weibull analysis was used to determine the Weibull modulus (m) and characteristic strength (σ0) of all groups. There were no major changes in strength for the infiltrated group, and homogeneity (m) was also increased. A layer of ZrSiO4 was formed on the surface. The bond strength to resin cement was improved after zirconia infiltration, acid conditioning and the use of an MDP primer. The sol-gel method is an efficient and simple method to increase the homogeneity of zirconia. Infiltration also improved bonding to resin cement. The performance of a zirconia infiltrated by silica gel improved in at least two ways: structural homogeneity and bonding to resin cement. The infiltration is simple to perform and can be easily managed in a prosthesis laboratory. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance improvement for solution-processed high-mobility ZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Sha Li, Chen; Li, Yu Ning; Wu, Yi Liang; Ong, Beng S.; Loutfy, Rafik O.

2008-06-01

The fabrication technology of stable, non-toxic, transparent, high performance zinc oxide (ZnO) thin-film semiconductors via the solution process was investigated. Two methods, which were, respectively, annealing a spin-coated precursor solution and annealing a drop-coated precursor solution, were compared. The prepared ZnO thin-film semiconductor transistors have well-controlled, preferential crystal orientation and exhibit superior field-effect performance characteristics. But the ZnO thin-film transistor (TFT) fabricated by annealing a drop-coated precursor solution has a distinctly elevated linear mobility, which further approaches the saturated mobility, compared with that fabricated by annealing a spin-coated precursor solution. The performance of the solution-processed ZnO TFT was further improved when substituting the spin-coating process by the drop-coating process.

Timing of occurrence is the most important characteristic of spot sign

PubMed Central

Xu, Mengjun; Zhang, Sheng; Liu, Keqin; Hu, Haitao; Selim, Magdy; Lou, Min

2016-01-01

Background and Purpose Most previous studies have used single-phase CT angiography (CTA) to detect the spot sign, a marker for hematoma expansion (HE) in spontaneous intracerebral hemorrhage (SICH). We investigated whether defining the spot sign based on timing on perfusion CT (CTP) would improve its specificity for predicting HE. Methods We prospectively enrolled supratentorial SICH patients, who underwent CTP within 6 h of onset. Logistic regression were performed to assess the risk factors for HE and poor outcome. Predictive performance of individual CTP spot sign characteristics were examined with receiver operating characteristic (ROC) analysis. Results Sixty-two men and 21 women with SICH were included in this analysis. Spot sign was detected in 46% (38/83) patients. ROC analysis indicated that the timing of spot sign occurrence on CTP had the greatest AUC for HE (0.794; 95% CI, 0.630-0.958; P=0.007); the cutoff time was 23.13 seconds. On multivariable analysis, the presence of early-occurring spot sign (EOSS; i.e. spot sign before 23.13 seconds) was an independent predictor, not only of HE (OR=28.835; 95% CI, 6.960-119.458; P<0.001), but also of mortality at 3 months (OR=22.377; 95% CI, 1.773-282.334; P=0.016). Moreover, the predictive performance showed that the redefined EOSS maintained a higher specificity for HE compared to spot sign (91% vs 74%). Conclusions Redefining the spot sign based on timing of contrast leakage on CTP to determine EOSS, improves the specificity for predicting HE and 3-month mortality. The use of EOSS could improve the selection of ICH patients for potential hemostatic therapy. PMID:27026627

Increases in lower-body strength transfer positively to sprint performance: a systematic review with meta-analysis.

PubMed

Seitz, Laurent B; Reyes, Alvaro; Tran, Tai T; Saez de Villarreal, Eduardo; Haff, G Gregory

2014-12-01

Although lower-body strength is correlated with sprint performance, whether increases in lower-body strength transfer positively to sprint performance remain unclear. This meta-analysis determined whether increases in lower-body strength (measured with the free-weight back squat exercise) transfer positively to sprint performance, and identified the effects of various subject characteristics and resistance-training variables on the magnitude of sprint improvement. A computerized search was conducted in ADONIS, ERIC, SPORTDiscus, EBSCOhost, Google Scholar, MEDLINE and PubMed databases, and references of original studies and reviews were searched for further relevant studies. The analysis comprised 510 subjects and 85 effect sizes (ESs), nested with 26 experimental and 11 control groups and 15 studies. There is a transfer between increases in lower-body strength and sprint performance as indicated by a very large significant correlation (r = -0.77; p = 0.0001) between squat strength ES and sprint ES. Additionally, the magnitude of sprint improvement is affected by the level of practice (p = 0.03) and body mass (r = 0.35; p = 0.011) of the subject, the frequency of resistance-training sessions per week (r = 0.50; p = 0.001) and the rest interval between sets of resistance-training exercises (r = -0.47; p ≤ 0.001). Conversely, the magnitude of sprint improvement is not affected by the athlete's age (p = 0.86) and height (p = 0.08), the resistance-training methods used through the training intervention, (p = 0.06), average load intensity [% of 1 repetition maximum (RM)] used during the resistance-training sessions (p = 0.34), training program duration (p = 0.16), number of exercises per session (p = 0.16), number of sets per exercise (p = 0.06) and number of repetitions per set (p = 0.48). Increases in lower-body strength transfer positively to sprint performance. The magnitude of sprint improvement is affected by numerous subject characteristics and resistance-training variables, but the large difference in number of ESs available should be taken into consideration. Overall, the reported improvement in sprint performance (sprint ES = -0.87, mean sprint improvement = 3.11 %) resulting from resistance training is of practical relevance for coaches and athletes in sport activities requiring high levels of speed.

[High resolution reconstruction of PET images using the iterative OSEM algorithm].

PubMed

Doll, J; Henze, M; Bublitz, O; Werling, A; Adam, L E; Haberkorn, U; Semmler, W; Brix, G

2004-06-01

Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction. All measurements were performed at the whole-body PET system ECAT EXACT HR(+) in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed. Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts. The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals.

Understanding the effect of hammering process on the vibration characteristics of cymbals

NASA Astrophysics Data System (ADS)

Kuratani, F.; Yoshida, T.; Koide, T.; Mizuta, T.; Osamura, K.

2016-09-01

Cymbals are thin domed plates used as percussion instruments. When cymbals are struck, they vibrate and radiate sound. Cymbals are made through spin forming, hammering, and lathing. The spin forming creates the basic shape of the cymbal, which determines its basic vibration characteristics. The hammering and lathing produce specific sound adjustments by changing the cymbal's vibration characteristics. In this study, we study how hammering cymbals affects their vibration characteristics. The hammering produces plastic deformation (small, shallow dents) on the cymbal's surface, generating residual stresses throughout it. These residual stresses change the vibration characteristics. We perform finite element analysis of a cymbal to obtain its stress distribution and the resulting change in vibration characteristics. To reproduce the stress distribution, we use thermal stress analysis, and then with this stress distribution we perform vibration analysis. These results show that each of the cymbal's modes has a different sensitivity to the thermal load (i.e., hammering). This difference causes changes in the frequency response and the deflection shape that significantly improves the sound radiation efficiency. In addition, we explain the changes in natural frequencies by the stress and modal strain energy distributions.

Low-Arousal Speech Noise Improves Performance in N-Back Task: An ERP Study

PubMed Central

Zhang, Dandan; Jin, Yi; Luo, Yuejia

2013-01-01

The relationship between noise and human performance is a crucial topic in ergonomic research. However, the brain dynamics of the emotional arousal effects of background noises are still unclear. The current study employed meaningless speech noises in the n-back working memory task to explore the changes of event-related potentials (ERPs) elicited by the noises with low arousal level vs. high arousal level. We found that the memory performance in low arousal condition were improved compared with the silent and the high arousal conditions; participants responded more quickly and had larger P2 and P3 amplitudes in low arousal condition while the performance and ERP components showed no significant difference between high arousal and silent conditions. These findings suggested that the emotional arousal dimension of background noises had a significant influence on human working memory performance, and that this effect was independent of the acoustic characteristics of noises (e.g., intensity) and the meaning of speech materials. The current findings improve our understanding of background noise effects on human performance and lay the ground for the investigation of patients with attention deficits. PMID:24204607

Performance improvement of AlGaN-based deep-ultraviolet light-emitting diodes via Al-composition graded quantum wells

NASA Astrophysics Data System (ADS)

Lu, Lin; Zhang, Yu; Xu, Fujun; Ding, Gege; Liu, Yuhang

2018-06-01

Characteristics of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) with step-like and Al-composition graded quantum wells have been investigated. The simulation results show that compared to DUV-LEDs with the conventional AlGaN multiple quantum wells (MQWs) structure, the light output power (LOP) and efficiency droop of DUV-LEDs with the Al-composition graded wells were remarkably improved. The key factor accounting for the improved performance is ascribed to the better modulation of carrier distribution in the quantum wells to increase the overlap between electron and hole wavefunctions, which contributes to more efficient recombination of electrons and holes, and thereby a significant enhancement in the LOP.

A Meta-analytic Review of Non-specific Effects in Randomized Controlled Trials of Cognitive Remediation for Schizophrenia.

PubMed

Radhakrishnan, Rajiv; Kiluk, Brian D; Tsai, Jack

2016-03-01

Cognitive remediation (CR) has been found to improve cognitive performance among adults with schizophrenia in randomized controlled trials (RCTs). However, improvements in cognitive performance are often observed in the control groups of RCTs as well. There has been no comprehensive examination of change in control groups for CR, which may inform trial methodology and improve our understanding of measured outcomes for cognitive remediation. In this meta-analysis, we calculated pre-post change in cognitive test performance within control groups of RCTs in 32 CR trials (n = 794 participants) published between 1970 and 2011, and examined the association between pre-post change and sample size, duration of treatment, type of control group, and participants' age, intelligence, duration of illness, and psychiatric symptoms. Results showed that control groups in CR trials showed small effect size changes (Cohen's d = 0.12 ± 0.16) in cognitive test performance over the trial duration. Study characteristics associated with pre-post change included participant age and sample size. These findings suggest attention to change in control groups may help improve detection of cognitive remediation effects for schizophrenia.

Working memory training using EEG neurofeedback in normal young adults.

PubMed

Xiong, Shi; Cheng, Chen; Wu, Xia; Guo, Xiaojuan; Yao, Li; Zhang, Jiacai

2014-01-01

Recent studies have shown that working memory (WM) performance can be improved by intensive and adaptive computerized training. Here, we explored the WM training effect using Electroencephalography (EEG) neurofeedback (NF) in normal young adults. In the first study, we identified the EEG features related to WM in normal young adults. The receiver operating characteristic (ROC) curve showed that the power ratio of the theta-to-alpha rhythms in the anterior-parietal region, accurately classified a high percentage of the EEG trials recorded during WM and fixation control (FC) tasks. Based on these results, a second study aimed to assess the training effects of the theta-to-alpha ratio and tested the hypothesis that up-regulating the power ratio can improve working memory behavior. Our results demonstrated that these normal young adults succeeded in improving their WM performance with EEG NF, and the pre- and post-test evaluations also indicated that WM performance increase in experimental group was significantly greater than control groups. In summary, our findings provided preliminarily evidence that WM performance can be improved through learned regulation of the EEG power ratio using EEG NF.

Variation in the utilization of reconstruction following mastectomy in elderly women.

PubMed

In, Haejin; Jiang, Wei; Lipsitz, Stuart R; Neville, Bridget A; Weeks, Jane C; Greenberg, Caprice C

2013-06-01

Regardless of their age, women who choose to undergo postmastectomy reconstruction report improved quality of life as a result. However, actual use of reconstruction decreases with increasing age. Whereas this may reflect patient preference and clinical factors, it may also represent age-based disparity. Women aged 65 years or older who underwent mastectomy for DCIS/stage I/II breast cancer (2000-2005) were identified in the SEER-Medicare database. Overall and institutional rates of reconstruction were calculated. Characteristics of hospitals with higher and lower rates of reconstruction were compared. Pseudo-R² statistics utilizing a patient-level logistic regression model estimated the relative contribution of institution and patient characteristics. A total of 19,234 patients at 716 institutions were examined. Overall, 6 % of elderly patients received reconstruction after mastectomy. Institutional rates ranged from zero to >40 %. Whereas 53 % of institutions performed no reconstruction on elderly patients, 5.6 % performed reconstructions on more than 20 %. Although patient characteristics (%ΔR² = 70 %), and especially age (%ΔR² = 34 %), were the primary determinants of reconstruction, institutional characteristics also explained some of the variation (%ΔR² = 16 %). This suggests that in addition to appropriate factors, including clinical characteristics and patient preferences, the use of reconstruction among older women also is influenced by the institution at which they receive care. Variation in the likelihood of reconstruction by institution and the association with structural characteristics suggests unequal access to this critical component of breast cancer care. Increased awareness of a potential age disparity is an important first step to improve access for elderly women who are candidates and desire reconstruction.

Variation in the Utilization of Reconstruction Following Mastectomy in Elderly Women

PubMed Central

In, Haejin; Jiang, Wei; Lipsitz, Stuart R.; Neville, Bridget A.; Weeks, Jane C.; Greenberg, Caprice C.

2014-01-01

Background Regardless of their age, women who choose to undergo postmastectomy reconstruction report improved quality of life as a result. However, actual use of reconstruction decreases with increasing age. Whereas this may reflect patient preference and clinical factors, it may also represent age-based disparity. Methods Women aged 65 years or older who underwent mastectomy for DCIS/stage I/II breast cancer (2000–2005) were identified in the SEER-Medicare database. Overall and institutional rates of reconstruction were calculated. Characteristics of hospitals with higher and lower rates of reconstruction were compared. Pseudo-R2 statistics utilizing a patient-level logistic regression model estimated the relative contribution of institution and patient characteristics. Results A total of 19,234 patients at 716 institutions were examined. Overall, 6 % of elderly patients received reconstruction after mastectomy. Institutional rates ranged from zero to >40 %. Whereas 53 % of institutions performed no reconstruction on elderly patients, 5.6 % performed reconstructions on more than 20 %. Although patient characteristics (%ΔR2 = 70 %), and especially age (%ΔR2 = 34 %), were the primary determinants of reconstruction, institutional characteristics also explained some of the variation (%ΔR2 = 16 %). This suggests that in addition to appropriate factors, including clinical characteristics and patient preferences, the use of reconstruction among older women also is influenced by the institution at which they receive care. Conclusions Variation in the likelihood of reconstruction by institution and the association with structural characteristics suggests unequal access to this critical component of breast cancer care. Increased awareness of a potential age disparity is an important first step to improve access for elderly women who are candidates and desire reconstruction. PMID:23263733

Study design and baseline characteristics of participants in the Vitamin D in Vulnerable Adults at the VA (the VIVA Study).

PubMed

Lagari, Violet S; Gómez-Marín, Orlando; Levis, Silvina

2014-09-01

Hypovitaminosis D has been associated with age-related physical decline and an increased risk for falls. The objective of this study is to test whether supplementation with 4000IU of vitamin D(3) (vitD(3)) for 9 months will improve, or slow down the decline of the ability to perform physical tests which have been associated with the preservation of independence in sedentary older men. We describe the study design and the baseline characteristics of the 314 men screened in the VIVA-VA Study (Vitamin D In Vulnerable Adults in the VA), a 2-year, single-site, double-blind, placebo-controlled, randomized clinical trial that enrolled sedentary male veterans ages 65 to 95. The main inclusion criteria are 25-OH vitamin D (25-OHD) levels between 10 and 30 ng/ml, and a Short Performance Physical Battery (SPPB) score ≤ 9. The primary outcome of the study is the SPPB. Subjects were recruited from the Miami Veterans Medical Center clinics. The study recruited 314 male veterans of multiethnic backgrounds. The baseline characteristics observed from the 314 men screened in the VIVA-VA Study are consistent with what is expected in a cohort of elderly sedentary men: low physical performance scores, and low 25OHD levels despite living in South Florida. The results of this study that uses a high dose of vitamin D in a cohort of sedentary older men could provide an evidence-based indication for vitamin D supplementation to improve physical performance in this population. Published by Elsevier Inc.

Productivity Improvement for Engineers.

DTIC Science & Technology

1981-08-01

organization, and the characteristics of the members of the organization at a given time. Ivancevich, Szilagyi and Wallace15 describe the contingency...1979,pp. 11 14. Ibid. 9 63 15. Ivancevich, Szllagyl and Wallace , Organizational Behavior and Performance,, GoodyearP~u-b Tshing Co., 1977, pp. 536. 16

Numerical investigation of the variable nozzle effect on the mixed flow turbine performance characteristics

NASA Astrophysics Data System (ADS)

Meziri, B.; Hamel, M.; Hireche, O.; Hamidou, K.

2016-09-01

There are various matching ways between turbocharger and engine, the variable nozzle turbine is the most significant method. The turbine design must be economic with high efficiency and large capacity over a wide range of operational conditions. These design intents are used in order to decrease thermal load and improve thermal efficiency of the engine. This paper presents an original design method of a variable nozzle vane for mixed flow turbines developed from previous experimental and numerical studies. The new device is evaluated with a numerical simulation over a wide range of rotational speeds, pressure ratios, and different vane angles. The compressible turbulent steady flow is solved using the ANSYS CFX software. The numerical results agree well with experimental data in the nozzleless configuration. In the variable nozzle case, the results show that the turbine performance characteristics are well accepted in different open positions and improved significantly in low speed regime and at low pressure ratio.

Optical-to-optical interface device. [consisting of two transparent electrodes on glass substrates that enclose thin film photoconductor and thin layer of nematic liquid crystal

NASA Technical Reports Server (NTRS)

Jacobson, A. D.

1973-01-01

Studies were conducted on the performance of a photoactivated dc liquid crystal light valve. The dc light valve is a thin film device that consists of two transparent electrodes, deposited on glass substrates, that enclose a thin film photoconductor (cadmium sulfide) and a thin layer of a nematic liquid crystal that operates in the dynamic scattering mode. The work was directed toward application of the light valve to high resolution non-coherent light to coherent light image conversion. The goal of these studies was to improve the performance and quality of the already existing dc light valve device and to evaluate quantitatively the properties and performance of the device as they relate to the coherent optical data processing application. As a result of these efforts, device sensitivity was improved by a factor of ten, device resolution was improved by a factor of three, device lifetime was improved by two-orders of magnitude, undesirable secondary liquid crystal scattering effects were eliminated, the scattering characteristics of the liquid crystal were thoroughly documented, the cosmetic quality of the devices was dramatically improved, and the performance of the device was fully documented.

Clinical Characteristics of Proper Robot-Assisted Gait Training Group in Non-ambulatory Subacute Stroke Patients

PubMed Central

Kim, Soo Jeong; Lee, Hye Jin; Hwang, Seung Won; Pyo, Hannah; Yang, Sung Phil; Lim, Mun-Hee; Park, Gyu Lee

2016-01-01

Objective To identify the clinical characteristics of proper robot-assisted gait training group using exoskeletal locomotor devices in non-ambulatory subacute stroke patients. Methods A total of 38 stroke patients were enrolled in a 4-week robotic training protocol (2 sessions/day, 5 times/week). All subjects were evaluated for their general characteristics, Functional Ambulatory Classification (FAC), Fugl-Meyer Scale (FMS), Berg Balance Scale (BBS), Modified Rankin Scale (MRS), Modified Barthel Index (MBI), and Mini-Mental Status Examination (MMSE) at 0, 2, and 4 weeks. Statistical analysis were performed to determine significant clinical characteristics for improvement of gait function after robot-assisted gait training. Results Paired t-test showed that all functional parameters except MMSE were improved significantly (p<0.05). The duration of disease and baseline BBS score were significantly (p<0.05) correlated with FAC score in multiple regression models. Receiver operating characteristic (ROC) curve showed that a baseline BBS score of '9' was a cutoff value (AUC, 0.966; sensitivity, 91%–100%; specificity, 85%). By repeated-measures ANOVA, the differences in improved walking ability according to time were significant between group of patients who had baseline BBS score of '9' and those who did not have baseline BBS score of '9' Conclusion Our results showed that a baseline BBS score above '9' and a short duration of disease were highly correlated with improved walking ability after robot-assisted gait training. Therefore, baseline BBS and duration of disease should be considered clinically for gaining walking ability in robot-assisted training group. PMID:27152266

Simulation and performance of brushless dc motor actuators

NASA Astrophysics Data System (ADS)

Gerba, A., Jr.

1985-12-01

The simulation model for a Brushless D.C. Motor and the associated commutation power conditioner transistor model are presented. The necessary conditions for maximum power output while operating at steady-state speed and sinusoidally distributed air-gap flux are developed. Comparison of simulated model with the measured performance of a typical motor are done both on time response waveforms and on average performance characteristics. These preliminary results indicate good agreement. Plans for model improvement and testing of a motor-driven positioning device for model evaluation are outlined.

Aiding planning in air traffic control: an experimental investigation of the effects of perceptual information integration.

PubMed

Moertl, Peter M; Canning, John M; Gronlund, Scott D; Dougherty, Michael R P; Johansson, Joakim; Mills, Scott H

2002-01-01

Prior research examined how controllers plan in their traditional environment and identified various information uncertainties as detriments to planning. A planning aid was designed to reduce this uncertainty by perceptually representing important constraints. This included integrating spatial information on the radar screen with discrete information (planned sequences of air traffic). Previous research reported improved planning performance and decreased workload in the planning aid condition. The purpose of this paper was to determine the source of these performance improvements. Analysis of computer interactions using log-linear modeling showed that the planning interface led to less repetitive--but more integrated--information retrieval compared with the traditional planning environment. Ecological interface design principles helped explain how the integrated information retrieval gave rise to the performance improvements. Actual or potential applications of this research include the design and evaluation of interface automation that keeps users in active control by modification of perceptual task characteristics.

Comparison of Colonoscopy Quality Measures Across Various Practice Settings and the Impact of Performance Scorecards.

PubMed

Inra, Jennifer A; Nayor, Jennifer; Rosenblatt, Margery; Mutinga, Muthoka; Reddy, Sarathchandra I; Syngal, Sapna; Kastrinos, Fay

2017-04-01

Quality performance measures for screening colonoscopy vary among endoscopists. The impact of practice setting is unknown. We aimed to (1) compare screening colonoscopy performance measures among three different US practice settings; (2) evaluate factors associated with adenoma detection; and (3) assess a scorecard intervention on performance metrics. This multi-center prospective study compared patient, endoscopist, and colonoscopy characteristics performed at a tertiary care hospital (TCH), community-based hospital (CBH), and private practice group (PPG). Withdrawal times (WT), cecal intubation, and adenoma detection rates (ADR) were compared by site at baseline and 12 weeks following scorecard distribution. Generalized linear mixed models identified factors associated with adenoma detection. Twenty-eight endoscopists performed colonoscopies on 1987 asymptomatic, average-risk individuals ≥50 years. Endoscopist and patient characteristics were similar across sites. The PPG screened more men (TCH: 42.8%, CBH: 45.0%, PPG: 54.2%; p < 0.0001). Preparation quality varied with good/excellent results in 70.6, 88.3, and 92% of TCH, CBH, and PPG cases, respectively (p < 0.0001). Male ADRs, cecal intubation, and WT exceeded recommended benchmarks despite variable results at each site; female ADRs were <15% at the PPG which screened the fewest females. Performance remained unchanged following scorecard distribution. Adenoma detection was associated with increasing patient age, male gender, WT, adequate preparation, but not practice setting. Each practice performed high-quality screening colonoscopy. Scorecards did not improve performance metrics. Preparation quality varies among practice settings and can be modified to improve adenoma detection.

Reader characteristics linked to detection of pulmonary nodules on radiographs: ROC vs. JAFROC analyses of performance

NASA Astrophysics Data System (ADS)

Kohli, Akshay; Robinson, John W.; Ryan, John; McEntee, Mark F.; Brennan, Patrick C.

2011-03-01

The purpose of this study is to explore whether reader characteristics are linked to heightened levels of diagnostic performance in chest radiology using receiver operating characteristic (ROC) and jackknife free response ROC (JAFROC) methodologies. A set of 40 postero-anterior chest radiographs was developed, of which 20 were abnormal containing one or more simulated nodules, of varying subtlety. Images were independently reviewed by 12 boardcertified radiologists including six chest specialists. The observer performance was measured in terms of ROC and JAFROC scores. For the ROC analysis, readers were asked to rate their degree of suspicion for the presence of nodules by using a confidence rating scale (1-6). JAFROC analysis required the readers to locate and rate as many suspicious areas as they wished using the same scale and resultant data were used to generate Az and FOM scores for ROC and JAFROC analyses respectively. Using Pearson methods, scores of performance were correlated with 7 reader characteristics recorded using a questionnaire. JAFROC analysis showed that improved reader performance was significantly (p<=0.05) linked with chest specialty (p<0.03), hours per week reading chest radiographs (p<0.03) and chest readings per year (p<0.04). ROC analyses demonstrated only one significant relationship, hours per week reading chest radiographs (p<0.02).The results of this study have shown that radiologist's performance in the detection of pulmonary nodules on radiographs is significantly linked to chest specialty, hours reading per week and number of radiographs read per year. Also, JAFROC is a more powerful predictor of performance as compared to ROC.

Impact of contextual factors and substance characteristics on perspectives toward cognitive enhancement.

PubMed

Sattler, Sebastian; Forlini, Cynthia; Racine, Eric; Sauer, Carsten

2013-01-01

Enhancing cognitive performance with substances--especially prescription drugs--is a fiercely debated topic among scholars and in the media. The empirical basis for these discussions is limited, given that the actual nature of factors that influence the acceptability of and willingness to use cognitive enhancement substances remains unclear. In an online factorial survey, contextual and substance-specific characteristics of substances that improve academic performance were varied experimentally and presented to respondents. Students in four German universities rated their willingness to use and moral acceptance of different substances for cognitive enhancement. We found that the overall willingness to use performance enhancing substances is low. Most respondents considered the use of these substances as morally unacceptable. Situational influences such as peer pressure, policies concerning substance use, relative performance level of peers, but also characteristics of the substance, such as perceptions of substance safety, shape the willingness and acceptability of using a substance to enhance academic performance. Among the findings is evidence of a contagion effect meaning that the willingness was higher when the respondents have more CE drug users in their social network. We also found deterrence effects from strong side effects of using the substance, as well as from policy regulations and sanctions. Regulations might activate social norms against usage and sanctions can be seen as costly to users. Moreover, enhancement substances seem to be most tempting to low performers to catch up with others compared to high performers. By identifying contextual factors and substance characteristics influencing the willingness and acceptability of cognitive enhancers, policy approaches could consider these insights to better manage the use of such substances.

The effect of poly ethylene glycol additive on the characteristics and performance of cellulose acetate ultrafiltration membrane for removal of Cr(III) from aqueous solution

NASA Astrophysics Data System (ADS)

Mulyati, S.; Aprilia, S.; Safiah; Syawaliah; Armando, M. A.; Mawardi, H.

2018-05-01

The effect of polyethylene glycol (PEG) additive on the characteristics and performance of the cellulose acetate ultrafiltration membrane to chromium metal removal has been studied using some variation of concentration in the casting solution. The concentration of cellulose acetate polymer was 17.5%, whereas the variations of PEG concentration were regulated at 0, 2.5, 5, 7.5 and 10% by weight. Dimethyl formamide (DMF) was used as a solvent. Pure water flux, membrane morphology test, functional group analysis, and molecular weight cut off (MWCO) were investigated to characterize of the prepared membranes. Membrane performance was tested against Cr(III) metal removal. The results confirmed that the pure water flux improved with the increasing of additive concentration. The maximum improvement occurred at membrane with modification using 7.5% PEG. At this PEG concentration, the pure water flux elevated from 49.5 L/m2.h to 62.2 L/m2.h. The addition of PEG successfully improved the membrane flux because the role PEG plays as a pore-forming agent. Membrane with addition of 7.5% PEG showcased rejection result for chromium metal of 31.89%. This value is lower than that of pure CA membrane which rejection value against Cr(III) metal amounted to 35.72%.

Precision Attitude Determination System (PADS) design and analysis. Two-axis gimbal star tracker

NASA Technical Reports Server (NTRS)

1973-01-01

Development of the Precision Attitude Determination System (PADS) focused chiefly on the two-axis gimballed star tracker and electronics design improved from that of Precision Pointing Control System (PPCS), and application of the improved tracker for PADS at geosynchronous altitude. System design, system analysis, software design, and hardware design activities are reported. The system design encompasses the PADS configuration, system performance characteristics, component design summaries, and interface considerations. The PADS design and performance analysis includes error analysis, performance analysis via attitude determination simulation, and star tracker servo design analysis. The design of the star tracker and electronics are discussed. Sensor electronics schematics are included. A detailed characterization of the application software algorithms and computer requirements is provided.

Performance improvement of organic thin film transistors by using active layer with sandwich structure

NASA Astrophysics Data System (ADS)

Ni, Yao; Zhou, Jianlin; Kuang, Peng; Lin, Hui; Gan, Ping; Hu, Shengdong; Lin, Zhi

2017-08-01

We report organic thin film transistors (OTFTs) with pentacene/fluorinated copper phthalo-cyanine (F16CuPc)/pentacene (PFP) sandwich configuration as active layers. The sandwich devices not only show hole mobility enhancement but also present a well control about threshold voltage and off-state current. By investigating various characteristics, including current-voltage hysteresis, organic film morphology, capacitance-voltage curve and resistance variation of active layers carefully, it has been found the performance improvement is mainly attributed to the low carrier traps and the higher conductivity of the sandwich active layer due to the additional induced carriers in F16CuPc/pentacene. Therefore, using proper multiple active layer is an effective way to gain high performance OTFTs.

Planar-Processed Polymer Transistors.

PubMed

Xu, Yong; Sun, Huabin; Shin, Eul-Yong; Lin, Yen-Fu; Li, Wenwu; Noh, Yong-Young

2016-10-01

Planar-processed polymer transistors are proposed where the effective charge injection and the split unipolar charge transport are all on the top surface of the polymer film, showing ideal device characteristics with unparalleled performance. This technique provides a great solution to the problem of fabrication limitations, the ambiguous operating principle, and the performance improvements in practical applications of conjugated-polymer transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

AGT 1500 Powerpack Improvement Project (M1 TMEPS). Volume 1

DTIC Science & Technology

1991-03-01

culminated in a one week evalUation of the ATR. This was due to funding and schedule constraints. Testing was concentrated on vehicle mobility performance...June 1990 with a one week vehicle demonstration at Milford Proving Grounds. The vehicle performed well but the mobility characteristics, most...all of the nonrecurring, recurring, engineering, data, system test and evaluation, and initial spares costs aplicable to each alternative. TMEPS as a

Oriental upper blepharoplasty.

PubMed

Weng, Chau-Jin

2009-02-01

Aesthetic surgery of the upper eyelids is a very common procedure performed in cosmetic practices around the world. The word blepharoplasty, however, has a different meaning in Asia than it does elsewhere. Orientals have different periorbital anatomic characteristics, their motivations for seeking eyelid treatment are different, and operative techniques have been adapted consequently. There are also many eyelid shapes among Orientals, mostly with regard to the presence and location of the supratarsal fold and/or presence of an epicanthal fold. The surgeon must therefore master a range of surgical procedures to treat these variations adequately. It is critical to know the indications for each blepharoplasty technique as well as their complications to select the right surgery and avoid unfavorable results. Epicanthoplasty performed on the right patient can greatly improve aesthetic results while retaining ethnic characteristics. This article will discuss Oriental eyelid characteristics, preoperative patient assessment, commonly used corrective techniques for the "double-eyelid" creation, and complications and how to avoid them.

Discerning direct and mediated effects of ecological structures and processes on adolescents' educational outcomes.

PubMed

Benner, Aprile D; Graham, Sandra; Mistry, Rashmita S

2008-05-01

This short-term longitudinal study examined the relations among family and school characteristics, family-level processes (youth perceptions of parent-adolescent interactions), school-level processes (youth perceptions of school belonging, school climate), adolescents' school engagement, and later academic performance. Participants were an ethnically diverse, urban sample of 1,120 9th-grade students (M age = 14.6 years). The structural characteristics of families and schools influenced the proximal processes that occurred therein, and these proximal processes, in turn, influenced students' proximal (i.e., engagement) and distal educational outcomes (i.e., grades in school). Moreover, the structural characteristics of families and schools influenced proximal and distal outcomes indirectly through their influence on the proximal processes. The multimediated ecological model suggested that intervening at the process level may be a successful means of improving both adolescents' engagement in school and their subsequent school performance. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

Indoor transformer stations and ELF magnetic field exposure: use of transformer structural characteristics to improve exposure assessment.

PubMed

Okokon, Enembe Oku; Roivainen, Päivi; Kheifets, Leeka; Mezei, Gabor; Juutilainen, Jukka

2014-01-01

Previous studies have shown that populations of multiapartment buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the relationship between childhood leukaemia and extremely-low-frequency (ELF) magnetic fields (MFs). This study investigated whether classification based on structural characteristics of the transformer stations would improve ELF MF exposure assessment. The data included MF measurements in apartments directly above transformer stations ("exposed" apartments) in 30 buildings in Finland, and reference apartments in the same buildings. Transformer structural characteristics (type and location of low-voltage conductors) were used to classify exposed apartments into high-exposure (HE) and intermediate-exposure (IE) categories. An exposure gradient was observed: both the time-average MF and time above a threshold (0.4 μT) were highest in the HE apartments and lowest in the reference apartments, showing a statistically significant trend. The differences between HE and IE apartments, however, were not statistically significant. A simulation exercise showed that the three-category classification did not perform better than a two-category classification (exposed and reference apartments) in detecting the existence of an increased risk. However, data on the structural characteristics of transformers is potentially useful for evaluating exposure-response relationship.

Improvement in performance and reliability with CF4 plasma pretreatment on the buffer oxide layer for low-temperature polysilicon thin-film transistor

NASA Astrophysics Data System (ADS)

Fan, Ching-Lin; Lin, Yi-Yan; Yang, Chun-Chieh

2012-03-01

This study applies CF4 plasma pretreatment to a buffer oxide layer to improve the performance of low-temperature polysilicon thin-film transistors (LTPS TFTs). Results show that the fluorine atoms piled up at the interface between the bulk channel and buffer oxide layer and accumulated in the bulk channel. The reduction of the trap states density by fluorine passivation can improve the electrical characteristics of the LTPS TFTs. It is found that the threshold voltage reduced from 4.32 to 3.03 V and the field-effect mobility increased from 29.71 to 45.65 cm2 V-1 S-1. In addition, the on current degradation and threshold voltage shift after stressing were significantly improved about 31% and 70%, respectively. We believe that the proposed CF4 plasma pretreatment on the buffer oxide layer can passivate the trap states and avoid the plasma induced damage on the polysilicon channel surface, resulting in the improvement in performance and reliability for LTPS-TFT mass production application on AMOLED displays with critical reliability requirement.

Tuning Monotonic Basin Hopping: Improving the Efficiency of Stochastic Search as Applied to Low-Thrust Trajectory Optimization

NASA Technical Reports Server (NTRS)

Englander, Jacob; Englander, Arnold

2014-01-01

Trajectory optimization methods using MBH have become well developed during the past decade. An essential component of MBH is a controlled random search through the multi-dimensional space of possible solutions. Historically, the randomness has been generated by drawing RVs from a uniform probability distribution. Here, we investigate the generating the randomness by drawing the RVs from Cauchy and Pareto distributions, chosen because of their characteristic long tails. We demonstrate that using Cauchy distributions (as first suggested by Englander significantly improves MBH performance, and that Pareto distributions provide even greater improvements. Improved performance is defined in terms of efficiency and robustness, where efficiency is finding better solutions in less time, and robustness is efficiency that is undiminished by (a) the boundary conditions and internal constraints of the optimization problem being solved, and (b) by variations in the parameters of the probability distribution. Robustness is important for achieving performance improvements that are not problem specific. In this work we show that the performance improvements are the result of how these long-tailed distributions enable MBH to search the solution space faster and more thoroughly. In developing this explanation, we use the concepts of sub-diffusive, normally-diffusive, and super-diffusive RWs originally developed in the field of statistical physics.

Initiating statistical process control to improve quality outcomes in colorectal surgery.

PubMed

Keller, Deborah S; Stulberg, Jonah J; Lawrence, Justin K; Samia, Hoda; Delaney, Conor P

2015-12-01

Unexpected variations in postoperative length of stay (LOS) negatively impact resources and patient outcomes. Statistical process control (SPC) measures performance, evaluates productivity, and modifies processes for optimal performance. The goal of this study was to initiate SPC to identify LOS outliers and evaluate its feasibility to improve outcomes in colorectal surgery. Review of a prospective database identified colorectal procedures performed by a single surgeon. Patients were grouped into elective and emergent categories and then stratified by laparoscopic and open approaches. All followed a standardized enhanced recovery protocol. SPC was applied to identify outliers and evaluate causes within each group. A total of 1294 cases were analyzed--83% elective (n = 1074) and 17% emergent (n = 220). Emergent cases were 70.5% open and 29.5% laparoscopic; elective cases were 36.8% open and 63.2% laparoscopic. All groups had a wide range in LOS. LOS outliers ranged from 8.6% (elective laparoscopic) to 10.8% (emergent laparoscopic). Evaluation of outliers demonstrated patient characteristics of higher ASA scores, longer operating times, ICU requirement, and temporary nursing at discharge. Outliers had higher postoperative complication rates in elective open (57.1 vs. 20.0%) and elective lap groups (77.6 vs. 26.1%). Outliers also had higher readmission rates for emergent open (11.4 vs. 5.4%), emergent lap (14.3 vs. 9.2%), and elective lap (32.8 vs. 6.9%). Elective open outliers did not follow trends of longer LOS or higher reoperation rates. SPC is feasible and promising for improving colorectal surgery outcomes. SPC identified patient and process characteristics associated with increased LOS. SPC may allow real-time outlier identification, during quality improvement efforts, and reevaluation of outcomes after introducing process change. SPC has clinical implications for improving patient outcomes and resource utilization.

A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

PubMed

Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

2013-01-01

A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

A Multihop Key Agreement Scheme for Wireless Ad Hoc Networks Based on Channel Characteristics

PubMed Central

Yu, Nenghai

2013-01-01

A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks. PMID:23766725

Comparing HE Policies in Europe

ERIC Educational Resources Information Center

Bleiklie, Ivar; Michelsen, Svein

2013-01-01

The purpose of this paper is to develop a conceptual framework for a comparative analysis of Higher Education policies that enables us to investigate the explanatory power of structural characteristics of politico-administrative systems. The policies that are studied aim at improving the efficiency and quality of institutional performance. The…

Low Power Consumption Design and Fabrication of Thin Film Core for Micro Fluxgate.

PubMed

Lv, Hui; Liu, Shibin

2016-03-01

The soft magnetic characteristic of core is a critical factor to performance of the micro fluxgate. Porous thin film core can be effectively used to decrease the value of saturation magnetic field strength (H(s)) and improve soft magnetic behavior. It is conducive to impelling the micro fluxgate toward the direction of low power consumption. In this work, negative photoresist is used to fabricate a porous core by MEMS technology. Through the processes of ultraviolet-lithography, the porous pattern transfer from the mask to the microstructure on silicon substrate. The experiment result complies with the anticipation and indicates that this MEMS technique can be applied to improve the characteristic of thin film core and decrease power consumption of fluxgate sensor.

Magnonic crystal as a delay line for low-noise auto-oscillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bankowski, Elena; Meitzler, Thomas; Khymyn, Roman S., E-mail: khiminr@gmail.com

2015-09-21

It is demonstrated that a delay line based on a one-dimensional magnonic crystal used in a feedback loop of a microwave auto-oscillator can substantially reduce the phase noise figure and improve other vital performance characteristics of the auto-oscillator. The advantage is achieved due to the increase of the effective delay time in the magnonic crystal, compared to the case of an un-patterned yttrium iron garnet (YIG) film, and improvement of the power-handling characteristics due to the now possible increase of the YIG film thickness. The internal modes of a magnonic crystal caused by the periodic energy exchange between the incidentmore » and reflected spin waves play the dominant role in the described effect.« less

Ternary binder based plasters with improved thermal insulating ability

NASA Astrophysics Data System (ADS)

Čáchová, M.; Koňáková, D.; Vejmelková, E.; Vyšvařil, M.

2017-10-01

New kind of plasters with improved thermal insulating ability are presented in this article. Improvement was reached by utilization of lightweight expanded perlite with high porosity. The second used aggregate was silica sand. Regarding the binder, three kind were combined for the reason of better plaster performance. Pure lime, Portland cement and pozzolanic ceramic powder were employed. Basic physical properties and thermal characteristics were determined. The porosity of plasters reached desired higher value about 50% and the thermal conductivity in dry state was lower than 0.16 Wm-1K-1.

Possibilities of further improvement of 1 s fluxgate variometers

NASA Astrophysics Data System (ADS)

Marusenkov, Andriy

2017-08-01

The paper discusses the possibility of improving temperature and noise characteristics of fluxgate variometers. The new fluxgate sensor with a Co-based amorphous ring core is described. This sensor is capable of improving the signal-to-noise ratio at the recording short-period geomagnetic variations. Besides the sensor performance, it is very important to create the high-stability compensation field that cancels the main Earth magnetic field inside the magnetic cores. For this purpose the new digitally controlled current source with low noise level and high temperature stability is developed.

Vicarious intergroup contact and the role of authorities in prejudice reduction.

PubMed

Gómez, Angel; Huici, Carmen

2008-05-01

The present study focuses on the effect of vicarious intergroup contact and the support of an authority figure on the improvement of outgroup and meta-stereotype evaluations. Meta-stereotype refers to the shared beliefs of ingroup members about how they consider outgroup members to perceive their group. Three preliminary studies were carried out to determine desirable and undesirable characteristics for a good basketball performance, the task that best demonstrates the application of these characteristics, and the two groups (basketball teams) that should be involved in the vicarious intergroup contact. Fans of one of the basketball teams participated in the current study. Vicarious intergroup contact improved outgroup and meta-stereotype evaluations as compared with a no contact condition. In addition, the positive effects of vicarious intergroup contact significantly increased when it was supported by an authority figure. More importantly, our study also shows that the improvement of outgroup evaluation was partially mediated by changes on meta-stereotypes.

Architecture for improved mass transport and system performance in redox flow batteries

NASA Astrophysics Data System (ADS)

Houser, Jacob; Pezeshki, Alan; Clement, Jason T.; Aaron, Douglas; Mench, Matthew M.

2017-05-01

In this work, electrochemical performance and parasitic losses are combined in an overall system-level efficiency metric for a high performance, all-vanadium redox flow battery. It was found that pressure drop and parasitic pumping losses are relatively negligible for high performance cells, i.e., those capable of operating at a high current density while at a low flow rate. Through this finding, the Equal Path Length (EPL) flow field architecture was proposed and evaluated. This design has superior mass transport characteristics in comparison with the standard serpentine and interdigitated designs at the expense of increased pressure drop. An Aspect Ratio (AR) design is discussed and evaluated, which demonstrates decreased pressure drop compared to the EPL design, while maintaining similar electrochemical performance under most conditions. This AR design is capable of leading to improved system energy efficiency for flow batteries of all chemistries.

Ambient response of a unique performance-based design building with dynamic response modification features

USGS Publications Warehouse

Çelebi, Mehmet; Huang, Moh; Shakal, Antony; Hooper, John; Klemencic, Ron

2012-01-01

A 64-story, performance-based design building with reinforced concrete core shear-walls and unique dynamic response modification features (tuned liquid sloshing dampers and buckling-restrained braces) has been instrumented with a monitoring array of 72 channels of accelerometers. Ambient vibration data recorded are analyzed to identify modes and associated frequencies and damping. The low-amplitude dynamic characteristics are considerably different than those computed from design analyses, but serve as a baseline against which to compare with future strong shaking responses. Such studies help to improve our understanding of the effectiveness of the added features to the building and help improve designs in the future.

Electrochemical doping for lowering contact barriers in organic field effect transistors

PubMed Central

Schaur, Stefan; Stadler, Philipp; Meana-Esteban, Beatriz; Neugebauer, Helmut; Serdar Sariciftci, N.

2012-01-01

By electrochemically p-doping pentacene in the vicinity of the source-drain electrodes in organic field effect transistors the injection barrier for holes is decreased. The focus of this work is put on the influence of the p-doping process on the transistor performance. Cyclic voltammetry performed on a pentacene based transistor exhibits a reversible p-doping response. This doped state is evoked at the transistor injection electrodes. An improvement is observed when comparing transistor characteristics before and after the doping process apparent by an improved transistor on-current. This effect is reflected in the analysis of the contact resistances of the devices. PMID:23483101

Measuring the performance of telephone-based disease surveillance systems in local health departments.

PubMed

Dausey, David J; Chandra, Anita; Schaefer, Agnes G; Bahney, Ben; Haviland, Amelia; Zakowski, Sarah; Lurie, Nicole

2008-09-01

We tested telephone-based disease surveillance systems in local health departments to identify system characteristics associated with consistent and timely responses to urgent case reports. We identified a stratified random sample of 74 health departments and conducted a series of unannounced tests of their telephone-based surveillance systems. We used regression analyses to identify system characteristics that predicted fast connection with an action officer (an appropriate public health professional). Optimal performance in consistently connecting callers with an action officer in 30 minutes or less was achieved by 31% of participating health departments. Reaching a live person upon dialing, regardless of who that person was, was the strongest predictor of optimal performance both in being connected with an action officer and in consistency of connection times. Health departments can achieve optimal performance in consistently connecting a caller with an action officer in 30 minutes or less and may improve performance by using a telephone-based disease surveillance system in which the phone is answered by a live person at all times.

Computer Drawing Method for Operating Characteristic Curve of PV Power Plant Array Unit

NASA Astrophysics Data System (ADS)

Tan, Jianbin

2018-02-01

According to the engineering design of large-scale grid-connected photovoltaic power stations and the research and development of many simulation and analysis systems, it is necessary to draw a good computer graphics of the operating characteristic curves of photovoltaic array elements and to propose a good segmentation non-linear interpolation algorithm. In the calculation method, Component performance parameters as the main design basis, the computer can get 5 PV module performances. At the same time, combined with the PV array series and parallel connection, the computer drawing of the performance curve of the PV array unit can be realized. At the same time, the specific data onto the module of PV development software can be calculated, and the good operation of PV array unit can be improved on practical application.

Reviewing the anaerobic digestion and co-digestion process of food waste from the perspectives on biogas production performance and environmental impacts.

PubMed

Chiu, Sam L H; Lo, Irene M C

2016-12-01

In this paper, factors that affect biogas production in the anaerobic digestion (AD) and anaerobic co-digestion (coAD) processes of food waste are reviewed with the aim to improve biogas production performance. These factors include the composition of substrates in food waste coAD as well as pre-treatment methods and anaerobic reactor system designs in both food waste AD and coAD. Due to the characteristics of the substrates used, the biogas production performance varies as different effects are exhibited on nutrient balance, inhibitory substance dilution, and trace metal element supplement. Various types of pre-treatment methods such as mechanical, chemical, thermal, and biological methods are discussed to improve the rate-limiting hydrolytic step in the digestion processes. The operation parameters of a reactor system are also reviewed with consideration of the characteristics of the substrates. Since the environmental awareness and concerns for waste management systems have been increasing, this paper also addresses possible environmental impacts of AD and coAD in food waste treatment and recommends feasible methods to reduce the impacts. In addition, uncertainties in the life cycle assessment (LCA) studies are also discussed.

Enhancement of hydrogen oxidation activity at a nickel coated carbon beads electrode by cobalt and iron

NASA Astrophysics Data System (ADS)

Chatterjee, A. K.; Banerjee, R.; Sharon, M.

The electrochemical characteristics of a porous ceramic that is coated with carbon beads, impregnated with Ni, Fe and Co catalyst and operated as a hydrogen electrode for an alkaline fuel cell (AFC) are studied. To improve the catalytic activity and electrode performance, Ni is bimetallized with Co as well as Fe. Chemical vapour deposition (CVD) of turpentine oil, a renewable natural precursor, is used to grow the carbon beads. Various compositions of Ni-Co and Ni-Fe (10:90, 50:50, 90:10) are electroplated over the carbon-coated ceramic substrate. The detailed surface profile and elemental composition of the electrodes are studied by SEM, TEM, XRD and XRF analysis. Vander-Pauw resistivity measurements of the electrodes showed an increase in the conductivity of Ni electrode by addition of Co and Fe. The electrochemical performance is investigated by measuring hydrogen dissociation voltage, half-cell and full-cell current-potential characteristics and chrono-potentiometry in 30% KOH solution. The activity of the NI electrode is improved by addition of small amounts of Co and Fe. The best performance is obtained using an electrode coated with 90:10 ratios of Ni-Co and Ni-Fe bimetallic composition.

Thin co-radial bipolar leads: technology and clinical performance.

PubMed

Fahraeus, T; Israel, C W; Wöllenstein, M

2001-09-01

While bipolar leads offer advantages such as better sensing performance than unipolar leads, their use has been limited by a larger lead diameter and reports about a high failure rate of several bipolar lead models. This has led to the development of thin bipolar leads using a special technology which aims at improving lead safety. Leads with monofilar thin conductors (drawn filled tube) which are individually coated with a very resistant material (ETFE) have been developed. Using a co-radial instead of co-axial bipolar conductor design, the lead diameter could be reduced to 4.5 F compared to 6-7 F of conventional bipolar leads. Bench testing demonstrated a significant improvement of this lead technology with respect to degradation of insulation material by biochemically reactive solutions. Also mechanical characteristics such as resistance to tearing forces and compression showed a high lead durability. From our own experience, co-radial bipolar leads show a favorable electrical performance with the exception of a relatively low pacing impedance. Also during long-term follow-up, the rate of lead failure was very low. These findings are corroborated by other clinical studies which also demonstrated good handling characteristics of thin bipolar leads during implantation.

Plasma Modification of Poly Lactic Acid Solutions to Generate High Quality Electrospun PLA Nanofibers.

PubMed

Rezaei, Fatemeh; Nikiforov, Anton; Morent, Rino; De Geyter, Nathalie

2018-02-02

Physical properties of pre-electrospinning polymer solutions play a key role in electrospinning as they strongly determine the morphology of the obtained electrospun nanofibers. In this work, an atmospheric-pressure argon plasma directly submerged in the liquid-phase was used to modify the physical properties of poly lactic acid (PLA) spinning solutions in an effort to improve their electrospinnability. The electrical characteristics of the plasma were investigated by two methods; V-I waveforms and Q-V Lissajous plots while the optical emission characteristics of the plasma were also determined using optical emission spectroscopy (OES). To perform a complete physical characterization of the plasma-modified polymer solutions, measurements of viscosity, surface tension, and electrical conductivity were performed for various PLA concentrations, plasma exposure times, gas flow rates, and applied voltages. Moreover, a fast intensified charge-couple device (ICCD) camera was used to image the bubble dynamics during the plasma treatments. In addition, morphological changes of PLA nanofibers generated from plasma-treated PLA solutions were observed by scanning electron microscopy (SEM). The performed plasma treatments were found to induce significant changes to the main physical properties of the PLA solutions, leading to an enhancement of electrospinnability and an improvement of PLA nanofiber formation.

Deficient symbol processing in Alzheimer disease.

PubMed

Toepper, Max; Steuwe, Carolin; Beblo, Thomas; Bauer, Eva; Boedeker, Sebastian; Thomas, Christine; Markowitsch, Hans J; Driessen, Martin; Sammer, Gebhard

2014-01-01

Symbols and signs have been suggested to improve the orientation of patients suffering from Alzheimer disease (AD). However, there are hardly any studies that confirm whether AD patients benefit from signs or symbols and which symbol characteristics might improve or impede their symbol comprehension. To address these issues, 30 AD patients and 30 matched healthy controls performed a symbol processing task (SPT) with 4 different item categories. A repeated-measures analysis of variance was run to identify impact of different item categories on performance accuracy in both the experimental groups. Moreover, SPT scores were correlated with neuropsychological test scores in a broad range of other cognitive domains. Finally, diagnostic accuracy of the SPT was calculated by a receiver-operating characteristic curve analysis. Results revealed a global symbol processing dysfunction in AD that was associated with semantic memory and executive deficits. Moreover, AD patients showed a disproportional performance decline at SPT items with visual distraction. Finally, the SPT total score showed high sensitivity and specificity in differentiating between AD patients and healthy controls. The present findings suggest that specific symbol features impede symbol processing in AD and argue for a diagnostic benefit of the SPT in neuropsychological assessment.

Effect of Caesalpinia coriaria Fruits and Soybean Oil on Finishing Lamb Performance and Meat Characteristics.

PubMed

Sánchez, Nallely; Mendoza, Germán David; Martínez, José Antonio; Hernández, Pedro Abel; Camacho Diaz, Luis Miguel; Lee-Rangel, Hector Aarón; Vazquez, Anayeli; Flores Ramirez, Rogelio

2018-01-01

To evaluate phenolic compounds and whether the combination of a tanniferous fruit and soybean oil could improve the performance, meat characteristics, and fatty acid (FA) profile in lambs, an experiment was conducted over 40 days with twenty creole male lambs (23.71 ± 3.46 kg). The lambs were allotted in a completely randomised design, with factorial arrangement 2 × 2, with the following dietary treatments: (1) control diet, (2) 2% Caesalpinia coriaria ground fruit dry matter (DM), (3) 2% soybean oil DM, and (4) 2% Caesalpinia coriaria fruit plus 2% soybean oil. The concentration of condensed tannins (CT) in Caesalpinia coriacea was 21.71 g/kg DM. No interactions were detected ( P > 0.05) among soybean oil and Caesalpinia coriaria , and there were no differences in daily gain, intake, and feed conversion. Soybean oil reduced ( P < 0.05) DM digestibility (68.05 versus 59.56%). In fat from the longissimus thoracis et lumborum (LTL) muscle, only linoleic acid presented differences ( P < 0.05) between treatments. The combination of Caesalpinia coriacea fruit and soybean oil did not improve lamb performance at the included levels.

Effect of Caesalpinia coriaria Fruits and Soybean Oil on Finishing Lamb Performance and Meat Characteristics

PubMed Central

Sánchez, Nallely; Camacho Diaz, Luis Miguel; Vazquez, Anayeli; Flores Ramirez, Rogelio

2018-01-01

To evaluate phenolic compounds and whether the combination of a tanniferous fruit and soybean oil could improve the performance, meat characteristics, and fatty acid (FA) profile in lambs, an experiment was conducted over 40 days with twenty creole male lambs (23.71 ± 3.46 kg). The lambs were allotted in a completely randomised design, with factorial arrangement 2 × 2, with the following dietary treatments: (1) control diet, (2) 2% Caesalpinia coriaria ground fruit dry matter (DM), (3) 2% soybean oil DM, and (4) 2% Caesalpinia coriaria fruit plus 2% soybean oil. The concentration of condensed tannins (CT) in Caesalpinia coriacea was 21.71 g/kg DM. No interactions were detected (P > 0.05) among soybean oil and Caesalpinia coriaria, and there were no differences in daily gain, intake, and feed conversion. Soybean oil reduced (P < 0.05) DM digestibility (68.05 versus 59.56%). In fat from the longissimus thoracis et lumborum (LTL) muscle, only linoleic acid presented differences (P < 0.05) between treatments. The combination of Caesalpinia coriacea fruit and soybean oil did not improve lamb performance at the included levels. PMID:29682572

A dynamic quality assessment tool for laparoscopic hysterectomy to measure surgical outcomes.

PubMed

Driessen, Sara R C; Van Zwet, Erik W; Haazebroek, Pascal; Sandberg, Evelien M; Blikkendaal, Mathijs D; Twijnstra, Andries R H; Jansen, Frank Willem

2016-12-01

The current health care system has an urgent need for tools to measure quality. A wide range of quality indicators have been developed in an attempt to differentiate between high-quality and low-quality health care processes. However, one of the main issues of currently used indicators is the lack of case-mix correction and improvement possibilities. Case-mix is defined as specific (patient) characteristics that are known to potentially affect (surgical) outcome. If these characteristics are not taken into consideration, comparisons of outcome among health care providers may not be valid. The objective of the study was to develop and test a quality assessment tool for laparoscopic hysterectomy, which can serve as a new outcome quality indicator. This is a prospective, international, multicenter implementation study. A web-based application was developed with 3 main goals: (1) to measure the surgeon's performance using 3 primary outcomes (blood loss, operative time, and complications); (2) to provide immediate individual feedback using cumulative observed-minus-expected graphs; and (3) to detect consistently suboptimal performance after correcting for case-mix characteristics. All gynecologists who perform laparoscopic hysterectomies were requested to register their procedures in the application. A patient safety risk factor checklist was used by the surgeon for reflection. Thereafter a prospective implementation study was performed, and the application was tested using a survey that included the System Usability Scale. A total of 2066 laparoscopic hysterectomies were registered by 81 gynecologists. Mean operative time was 100 ± 39 minutes, blood loss 127 ± 163 mL, and the complication rate 6.1%. The overall survey response rate was 75%, and the mean System Usability Scale was 76.5 ± 13.6, which indicates that the application was good to excellent. The majority of surgeons reported that the application made them more aware of their performance, the outcomes, and patient safety, and they noted that the application provided motivation for improving future performance. We report the development and test of a real-time, dynamic, quality assessment tool for measuring individual surgical outcome for laparoscopic hysterectomy. Importantly, this tool provides opportunities for improving surgical performance. Our study provides a foundation for helping clinicians develop evidence-based quality indicators for other surgical procedures. Copyright © 2016 Elsevier Inc. All rights reserved.

Developing a theory of the strategic core of teams: a role composition model of team performance.

PubMed

Humphrey, Stephen E; Morgeson, Frederick P; Mannor, Michael J

2009-01-01

Although numerous models of team performance have been articulated over the past 20 years, these models have primarily focused on the individual attribute approach to team composition. The authors utilized a role composition approach, which investigates how the characteristics of a set of role holders impact team effectiveness, to develop a theory of the strategic core of teams. Their theory suggests that certain team roles are most important for team performance and that the characteristics of the role holders in the "core" of the team are more important for overall team performance. This theory was tested in 778 teams drawn from 29 years of major league baseball (1974'-2002). Results demonstrate that although high levels of experience and job-related skill are important predictors of team performance, the relationships between these constructs and team performance are significantly stronger when the characteristics are possessed by core role holders (as opposed to non-core role holders). Further, teams that invest more of their financial resources in these core roles are able to leverage such investments into significantly improved performance. These results have implications for team composition models, as they suggest a new method for considering individual contributions to a team's success that shifts the focus onto core roles. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Creeping flashover characteristics improvement of nanofluid/pressboard system with TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Huang, Meng; Wang, Lei; Ge, Yang; Lv, Yu-zhen; Qi, Bo; Li, Cheng-rong

2018-03-01

Creeping flashover easily occurs at the interface between oil and pressboard in transformer and thus results in outage of power transmission system. Investigations have shown that creeping flashover characteristics at oil/pressboard interface can be improved by the addition of TiO2 nanoparticles, but the mechanism is still not thoroughly known. In this work, creeping flashover performance at nanofluid/pressboard interface modified by different sizes of nanoparticles were studied and the mechanism was presented as well. Nanofluids with the same concentration but with different sizes of TiO2 nanoparticles were prepared, and pressboards impregnated with them were prepared as well. After that, their creeping flashover characteristics were measured and compared. Nanoparticle's size affected the creeping flashover performance along oil/pressboard greatly under both AC and lightning impulse voltages. The highest creeping flashover voltage can be enhanced by as high as 12.2% and 32.0% respectively. The underlying electric field distribution and charge transportation behaviors were analyzed to demonstrate the influence of nanoparticle's size. By the addition of nanoparticles with a smaller size, the dielectric constant of nanofluid was increased closer to that of the pressboard, thus they were matched better. Moreover, charge was easier to dissipate from the oil/pressboard interface and electric field distortion at the interface was consequently reduced. Therefore, the electric field was more like a uniform field and the forward development of flashover was more difficult, leading to a better performance of creeping flashover of oil-impregnated pressboard.

Effect of ractopamine hydrochloride (Optaflexx) dose and duration on growth performance and carcass characteristics of finishing steers.

PubMed

Bittner, C J; Crawford, G I; Berger, L L; Holt, S; Pritchard, R R; Platter, W J; Van Koevering, M T; Pyatt, N A; Erickson, G E

2016-12-01

Three experiments evaluated the effects of ractopamine hydrochloride (RAC) dose and duration on growth performance and carcass characteristics of feedlot steers. In total, 1,509 crossbred steers (530 kg initial BW [SD 22]) were used in a randomized complete block design using a 3 × 3 factorial treatment structure. Treatments consisted of RAC dose (0, 100, or 200 mg/steer daily) and duration (28, 35, or 42 d) of RAC feeding prior to harvest. Initiation of RAC dose was staggered (7 d apart) based on RAC duration, which resulted in common days on feed among treatments. Data from the 3 experiments were combined for statistical analyses. There were no RAC dose × duration interactions ( ≥ 0.85) for growth performance. Live final BW was not different ( ≥ 0.24) as RAC dose increased. Dry matter intake linearly decreased ( < 0.01) as RAC dose increased. Live ADG and G:F linearly increased ( ≤ 0.01) as RAC dose increased. Carcass-adjusted ADG and G:F linearly increased ( ≤ 0.02) as RAC dose increased. Compared with steers fed 0 mg RAC/steer daily, G:F was improved by 5.0 and 13.0% when steers were fed 100 ( = 0.31) and 200 ( = 0.01) mg RAC/steer daily, respectively. Hot carcass weight tended ( = 0.10) to linearly increase as RAC dose increased, with carcasses from steers fed 100 ( = 0.38) and 200 ( = 0.10) mg RAC/steer daily being 2.2 and 4.1 kg heavier, respectively, than carcasses from steers fed 0 mg RAC/steer daily. Increasing RAC dose linearly ( < 0.01) increased LM area and linearly ( = 0.02) decreased marbling score. Live final BW was not different ( ≥ 0.60) among RAC durations. Carcass-adjusted final BW, ADG, and G:F were not different ( ≥ 0.41) as RAC duration increased. Carcass traits did not differ ( ≥ 0.18) among RAC duration. Feeding 200 mg RAC/steer daily improved ADG, feed efficiency, and HCW. Increasing the feeding duration of RAC had no effect of growth performance or carcass characteristics. These data indicate that feeding 200 mg RAC/steer daily for 28 d improves steer growth performance.

Effects of different limestone particle sizes in the diet of broiler breeders post molting on their performance, egg quality, incubation results, and pre-starter performance of their progeny.

PubMed

Bueno, I J M; Surek, D; Rocha, C; Schramm, V G; Muramatsu, K; Dahlke, F; Maiorka, A

2016-04-01

An experiment was conducted to test the hypothesis that a coarse limestone diet improves productivity, reproductive performance and the calcium utilization of molted broiler breeders. In total, 640 broiler breeder females, 73-week-old and sixty-four 27-week-old cockerels, Cobb 500, were evaluated during 10 weeks, according to a randomized block design composed of 4 treatments with 8 replicates each. Treatments consisted of diets with the inclusion of 100% fine limestone-fine PS (0.2 mm GMD-geometric mean diameter); PS1: 30% fine limestone+70% limestone with 1.0 mm GMD; PS2: 30% fine limestone+70% limestone with 2.0 mm GMD; and PS3: 30% fine limestone+70% limestone with 3.0 mm GMD. Calcium retention in the gizzard of the breeders, bone characteristics, and breeder performance, egg characteristics, eggshell quality, incubation performance, chick quality and yield, chick pre-starter live performance, and chick bone characteristics were determined. There was no significant difference (P>0.05) in the rate of lay, percentage of non-settable eggs, egg weight, egg shape index, egg specific gravity, eggshell weight, thickness, and percentage hatchability and egg weight loss of broiler breeders fed with diets with different limestone particle sizes. The chick quality and yield, chick pre-starter live performance, and chick bone characteristics were not affected (P>0.05) by any of the limestone particle sizes. It was concluded that live and reproductive performance parameters of broiler breeders post molting is not affected by limestone particle size in the feed. © 2016 Poultry Science Association Inc.

Simulation and Experimental Investigation of Structural Dynamic Frequency Characteristics Control

PubMed Central

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results. PMID:22666072

Simulation and experimental investigation of structural dynamic frequency characteristics control.

PubMed

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results.

DC and analog/RF performance optimisation of source pocket dual work function TFET

NASA Astrophysics Data System (ADS)

Raad, Bhagwan Ram; Sharma, Dheeraj; Kondekar, Pravin; Nigam, Kaushal; Baronia, Sagar

2017-12-01

We investigate a systematic study of source pocket tunnel field-effect transistor (SP TFET) with dual work function of single gate material by using uniform and Gaussian doping profile in the drain region for ultra-low power high frequency high speed applications. For this, a n+ doped region is created near the source/channel junction to decrease the depletion width results in improvement of ON-state current. However, the dual work function of the double gate is used for enhancement of the device performance in terms of DC and analog/RF parameters. Further, to improve the high frequency performance of the device, Gaussian doping profile is considered in the drain region with different characteristic lengths which decreases the gate to drain capacitance and leads to drastic improvement in analog/RF figures of merit. Furthermore, the optimisation is performed with different concentrations for uniform and Gaussian drain doping profile and for various sectional length of lower work function of the gate electrode. Finally, the effect of temperature variation on the device performance is demonstrated.

Preconditioned characteristic boundary conditions based on artificial compressibility method for solution of incompressible flows

NASA Astrophysics Data System (ADS)

Hejranfar, Kazem; Parseh, Kaveh

2017-09-01

The preconditioned characteristic boundary conditions based on the artificial compressibility (AC) method are implemented at artificial boundaries for the solution of two- and three-dimensional incompressible viscous flows in the generalized curvilinear coordinates. The compatibility equations and the corresponding characteristic variables (or the Riemann invariants) are mathematically derived and then applied as suitable boundary conditions in a high-order accurate incompressible flow solver. The spatial discretization of the resulting system of equations is carried out by the fourth-order compact finite-difference (FD) scheme. In the preconditioning applied here, the value of AC parameter in the flow field and also at the far-field boundary is automatically calculated based on the local flow conditions to enhance the robustness and performance of the solution algorithm. The code is fully parallelized using the Concurrency Runtime standard and Parallel Patterns Library (PPL) and its performance on a multi-core CPU is analyzed. The incompressible viscous flows around a 2-D circular cylinder, a 2-D NACA0012 airfoil and also a 3-D wavy cylinder are simulated and the accuracy and performance of the preconditioned characteristic boundary conditions applied at the far-field boundaries are evaluated in comparison to the simplified boundary conditions and the non-preconditioned characteristic boundary conditions. It is indicated that the preconditioned characteristic boundary conditions considerably improve the convergence rate of the solution of incompressible flows compared to the other boundary conditions and the computational costs are significantly decreased.

The influence of Span-20 surfactant and micro-/nano-Chromium (Cr) Powder Mixed Electrical Discharge Machining (PMEDM) on the surface characteristics of AISI D2 hardened steel

NASA Astrophysics Data System (ADS)

Hosni, N. A. J.; Lajis, M. A.

2018-04-01

The application of powder mixed dielectric to improve the efficiency of electrical discharge machining (EDM) has been extensively studied. Therefore, PMEDM have attracted the attention of many researchers since last few decades. Improvement in EDM process has resulted in the use of span-20 surfactant and Cr powder mixed in dielectric fluid, which results in increasing machiniability, better surface quality and faster machining time. However, the study of powder suspension size of surface charateristics in EDM field is still limited. This paper presents the improvement of micro-/nano- Cr powder size on the surface characteristics of the AISI D2 hardened steels in PMEDM. It has found that the reacst layer in PMEDM improved by as high as 41-53 % compared to conventional EDM. Also notably, the combination of added Cr powder and span-20 surfactant reduced the recast layer thickness significantly especially in nano-Cr size. This improvement was great potential adding nano-size Cr powder to dielectric for machining performance.

Study on the Characteristics of Plasma Profiles in Improved Confinement Plasmas in HT-7 Superconducting Tokamak

NASA Astrophysics Data System (ADS)

Zhang, Shouyin; Gao, Xiang; Li, Jiangang; Wan, Baonian; Kuang, Guangli; Mao, Jianshan; Zhang, Xiaodong; Xie, Jikang; Wan, Yuanxi; Team HT-7

2000-10-01

In HT-7 superconducting tokamak of circular limiter configuration (R0=122cm, a=30cm, Bt:1 ~2.2T), plasma profiles were modified and controlled by means of gas puffing, supersonic molecule injection, pellet injection, ICRF and IBW heating as well as LHW heating and current drive; improved plasma confinements were achieved either by application of one of the above measures or by the combination of them, study of the effects of the characteristics of plasma profiles on plasma confinements were performed. The results show that in most of the improved confinement plasmas in HT-7, there are very steep and strong peeking electron temperature profiles in core plasma, and/or large decrease of local temperature in radius of 0.5 ~0.7a which makes temperature gradient steeper when improvements begin, as temperature profile evolves back to previous normal shape the improvements end. Electron density profile and soft X-ray profiles were studied as well. This research was supported under Natural Science Foundation of China contract No.19905010.

Mechanical parameters and flight phase characteristics in aquatic plyometric jumping.

PubMed

Louder, Talin J; Searle, Cade J; Bressel, Eadric

2016-09-01

Plyometric jumping is a commonly prescribed method of training focused on the development of reactive strength and high-velocity concentric power. Literature suggests that aquatic plyometric training may be a low-impact, effective supplement to land-based training. The purpose of the present study was to quantify acute, biomechanical characteristics of the take-off and flight phase for plyometric movements performed in the water. Kinetic force platform data from 12 young, male adults were collected for counter-movement jumps performed on land and in water at two different immersion depths. The specificity of jumps between environmental conditions was assessed using kinetic measures, temporal characteristics, and an assessment of the statistical relationship between take-off velocity and time in the air. Greater peak mechanical power was observed for jumps performed in the water, and was influenced by immersion depth. Additionally, the data suggest that, in the water, the statistical relationship between take-off velocity and time in air is quadratic. Results highlight the potential application of aquatic plyometric training as a cross-training tool for improving mechanical power and suggest that water immersion depth and fluid drag play key roles in the specificity of the take-off phase for jumping movements performed in the water.

Evaluation of litter type and dietary coarse ground corn inclusion on broiler live performance, gastrointestinal tract development, and litter characteristics.

PubMed

Xu, Y; Stark, C R; Ferket, P R; Williams, C M; Nusairat, B; Brake, J

2015-03-01

Two 49 d floor pen studies were conducted to evaluate the effects of litter type and dietary coarse ground corn (CC) inclusion on broiler live performance, gastrointestinal tract (GIT) development, and litter characteristics. Experiment 1 was a 2×2 factorial arrangement of 2 genders (male or female) and 2 CC levels (0 or 50%). From 15 to 35 d, the addition of CC decreased feed intake (P<0.01) and BW gain (P<0.05) of males but not females. The inclusion of CC decreased feed intake (P<0.01) and BW gain (P<0.01) from 0 to 49 d but improved adjusted feed conversion ratio (AdjFCR) from 35 to 49 d (P<0.05). Male broilers exhibited better live performance than females during the study as evidenced by greater feed intake (P<0.01) and BW gain (P<0.01), and improved FCR (P<0.01), but with increased mortality (P<0.05). The inclusion of CC increased relative gizzard weight (P<0.01) and decreased relative proventriculus weight (P<0.01) at 49 d. Experiment 2 was a 2×2 factorial arrangement of 2 CC levels (0 or 50%) and 2 litter types (ground old litter or new wood shavings litter). The inclusion of CC decreased feed intake throughout the experiment without affecting final BW when only males were used and improved FCR after 25 d (P<0.01). New litter improved FCR from 1 to 14 d (P<0.01). At 49 d, the birds fed the CC diet had reduced excreta nitrogen (P<0.05) and litter moisture (P<0.05). In conclusion, 50% CC inclusion initially produced negative effects on live performance that became positive as BW increased. The effects of CC became evident at an earlier age for males. New litter had only a marginal benefit on broiler live performance. © 2015 Poultry Science Association Inc.

Highly effective cystic fibrosis clinical research teams: critical success factors.

PubMed

Retsch-Bogart, George Z; Van Dalfsen, Jill M; Marshall, Bruce C; George, Cynthia; Pilewski, Joseph M; Nelson, Eugene C; Goss, Christopher H; Ramsey, Bonnie W

2014-08-01

Bringing new therapies to patients with rare diseases depends in part on optimizing clinical trial conduct through efficient study start-up processes and rapid enrollment. Suboptimal execution of clinical trials in academic medical centers not only results in high cost to institutions and sponsors, but also delays the availability of new therapies. Addressing the factors that contribute to poor outcomes requires novel, systematic approaches tailored to the institution and disease under study. To use clinical trial performance metrics data analysis to select high-performing cystic fibrosis (CF) clinical research teams and then identify factors contributing to their success. Mixed-methods research, including semi-structured qualitative interviews of high-performing research teams. CF research teams at nine clinical centers from the CF Foundation Therapeutics Development Network. Survey of site characteristics, direct observation of team meetings and facilities, and semi-structured interviews with clinical research team members and institutional program managers and leaders in clinical research. Critical success factors noted at all nine high-performing centers were: 1) strong leadership, 2) established and effective communication within the research team and with the clinical care team, and 3) adequate staff. Other frequent characteristics included a mature culture of research, customer service orientation in interactions with study participants, shared efficient processes, continuous process improvement activities, and a businesslike approach to clinical research. Clinical research metrics allowed identification of high-performing clinical research teams. Site visits identified several critical factors leading to highly successful teams that may help other clinical research teams improve clinical trial performance.

Match running performance and skill execution improves with age but not the number of disposals in young Australian footballers.

PubMed

Gastin, Paul B; Tangalos, Christie; Torres, Lorena; Robertson, Sam

2017-12-01

This study investigated age-related differences in maturity, physical and functional characteristics and playing performance in youth Australian Football (AF). Young male players (n = 156) were recruited from 12 teams across 6 age groups (U10-U15) of a recreational AF club. All players were tested for body size, maturity and fitness. Player performance was assessed during a match in which disposals (kicks and handballs) and their effectiveness were coded from a video recording and match running performance measured using Global Positioning System. Significant main effects (P < 0.01) for age group were observed for age, years to peak height velocity, body mass, height, 20 m sprint, maximal speed over 20 m, vertical jump, 20 m multistage shuttle run, match distance, high-speed running distance, peak speed, number of effective disposals and percentage of effective disposals. Age-related differences in fitness characteristics (speed, lower body power and endurance) appeared to transfer to match running performance. The frequency in which players disposed of the football did not differ between age groups, however the effectiveness of each disposal (i.e., % effective disposals) improved with age. Match statistics, particularly those that evaluate skill execution outcome (i.e., effectiveness), are useful to assess performance and to track player development over time. Differences between age groups, and probably variability within age groups, are strongly associated with chronological age and maturity.

Selective attention deficits in obsessive-compulsive disorder: the role of metacognitive processes.

PubMed

Koch, Julia; Exner, Cornelia

2015-02-28

While initial studies supported the hypothesis that cognitive characteristics that capture cognitive resources act as underlying mechanisms in memory deficits in obsessive-compulsive disorder (OCD), the influence of those characteristics on selective attention has not been studied, yet. In this study, we examined the influence of cognitive self-consciousness (CSC), rumination and worrying on performance in selective attention in OCD and compared the results to a depressive and a healthy control group. We found that 36 OCD and 36 depressive participants were impaired in selective attention in comparison to 36 healthy controls. In all groups, hierarchical regression analyses demonstrated that age, intelligence and years in school significantly predicted performance in selective attention. But only in OCD, the predictive power of the regression model was improved when CSC, rumination and worrying were implemented as predictor variables. In contrast, in none of the three groups the predictive power improved when indicators of severity of obsessive-compulsive (OC) and depressive symptoms and trait anxiety were introduced as predictor variables. Thus, our results support the assumption that mental characteristics that bind cognitive resources play an important role in the understanding of selective attention deficits in OCD and that this mechanism is especially relevant for OCD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Improvement of the environmental and operational characteristics of vehicles through decreasing the motor fuel density.

PubMed

Magaril, Elena

2016-04-01

The environmental and operational characteristics of motor transport, one of the main consumers of motor fuel and source of toxic emissions, soot, and greenhouse gases, are determined to a large extent by the fuel quality which is characterized by many parameters. Fuel density is one of these parameters and it can serve as an indicator of fuel quality. It has been theoretically substantiated that an increased density of motor fuel has a negative impact both on the environmental and operational characteristics of motor transport. The use of fuels with a high density leads to an increase in carbonization within the engine, adversely affecting the vehicle performance and increasing environmental pollution. A program of technological measures targeted at reducing the density of the fuel used was offered. It includes a solution to the problem posed by changes in the refining capacities ratio and the temperature range of gasoline and diesel fuel boiling, by introducing fuel additives and adding butanes to the gasoline. An environmental tax has been developed which allows oil refineries to have a direct impact on the production of fuels with improved environmental performance, taking into account the need to minimize the density of the fuel within a given category of quality.

Contributions to modeling functionality of a high frequency damper system

NASA Astrophysics Data System (ADS)

Sirbu, E. A.; Horga, S.; Vrabioiu, G.

2016-08-01

Due to the necessity of improving the handling performances of a motor vehicle, it is imperative to understand the suspensions properties that affects ride and directional respons.The construction of a fero-magnetic shock absorber is based on two bellows interconnected by a pipe-line. Through this pipe-line the fero-magnetic fluid is carried between the two bellows. The damping characteristic of the shock absorber is affected by the viscosity of the fero-magnetic fluid. The viscosity of the fluid, is controlled through a electric coil mounted on the bellows connecting pipe-line. Modifying the electrical field of the coil, the viscosity of the fluid will change, finally affecting the damping characteristic of the shock absorber. A recent system called „CCD Pothole Suspension” is implemented on Ford vehicles. By modifying the dampning characteristic of the shock absorbers, vehicle daynamics can be improved; also the risk of damaging the suspension will be decreased. The approach of this paper is to analyze the behaviour of the fero magnetic damper, thus determining how it will affect the performances of the vehicle suspensions. The experimental research will provide a better understanding of the behavior of the fero-magnetic shock absorber, and the possible advantages of using this system.

Self-reported assistive technology outcomes and personal characteristics in college students with less-apparent disabilities.

PubMed

Malcolm, Matt P; Roll, Marla C

2017-11-20

The impact of assistive technology (AT) services for college students with less-apparent disabilities is under-reported. Using the Canadian Occupational Performance Measure (COPM), we assessed student Performance and Satisfaction ratings of common academic tasks at the start and end of a semester during which 105 student-clients with less-apparent disabilities received AT services. We examined if COPM scores related to personal characteristics of gender, class-level (e.g., Sophomore), and STEM education; if personal characteristics predicted a student's follow-through with an AT service referral (n=231); and if personal characteristics and initial COPM scores predicted dropout from AT services (n=187). COPM ratings significantly increased in all academic tasks (p<.001). Gender predicted initial Satisfaction (male ratings > female ratings; p=.01), and Performance changes (females were more likely to have a service-meaningful change; p=.02). Higher class-level predicted better follow-through with a referral for AT services (p=.006). Increasing class-level (p=.05) and higher initial studying (p<.006) and reading (p<.029) ratings predicted a lower likelihood for dropout. These findings demonstrate that college students with less-apparent disabilities experience substantial improvements in their self-ratings of academic performance and satisfaction following AT services. Gender, class-level, and initial self-perceived reading and studying abilities may influence if and how the student participates with AT services.

Effects of wheat source and particle size in meal and pelleted diets on finishing pig growth performance, carcass characteristics, and nutrient digestibility.

PubMed

De Jong, J A; DeRouchey, J M; Tokach, M D; Dritz, S S; Goodband, R D; Paulk, C B; Woodworth, J C; Jones, C K; Stark, C R

2016-08-01

Two experiments were conducted to test the effects of wheat source and particle size in meal and pelleted diets on finishing pig performance, carcass characteristics, and diet digestibility. In Exp. 1, pigs (PIC 327 × 1050; = 288; initially 43.8 kg BW) were balanced by initial BW and randomly allotted to 1 of 3 treatments with 8 pigs per pen (4 barrows and 4 gilts) and 12 pens per treatment. The 3 dietary treatments were hard red winter wheat ground with a hammer mill to 728, 579, or 326 μm, respectively. From d 0 to 40, decreasing wheat particle size decreased (linear, < 0.033) ADFI but improved (quadratic, < 0.014) G:F. From d 40 to 83, decreasing wheat particle size increased (quadratic, < 0.018) ADG and improved (linear, < 0.002) G:F. Overall from d 0 to 83, reducing wheat particle size improved (linear, < 0.002) G:F. In Exp. 2, pigs (PIC 327 × 1050; = 576; initially 43.4 ± 0.02 kg BW) were used to determine the effects of wheat source and particle size of pelleted diets on finishing pig growth performance and carcass characteristics. Pigs were randomly allotted to pens, and pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments with 12 replications per treatment and 8 pigs/pen. The experimental diets used the same wheat-soybean meal formulation, with the 6 treatments using hard red winter or soft white winter wheat that were processed to 245, 465, and 693 μm and 258, 402, and 710 μm, respectively. All diets were pelleted. Overall, feeding hard red winter wheat increased ( < 0.05) ADG and ADFI when compared with soft white winter wheat. There was a tendency ( < 0.10) for a quadratic particle size × wheat source interaction for ADG, ADFI, and both DM and GE digestibility, as they were decreased for pigs fed 465-μm hard red winter wheat and were greatest for pigs fed 402-μm soft white winter wheat. There were no main or interactive effects of particle size or wheat source on carcass characteristics. In summary, fine grinding hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas reducing particle size of wheat from approximately 700 to 250 μm in pelleted diets did not influence growth or carcass traits. Finally, feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat.

Growth performance, survival, and processing characteristics of hybrid catfish fed pre And probiotics

USDA-ARS?s Scientific Manuscript database

There has been a lot of interest in the use of pre and probiotics to increase growth and improve disease resistance in the catfish industry. This study aimed to evaluate a commercially available prebiotic and probiotic under conditions simulating commercial production in hybrid catfish. The dietar...

Use of ß-adrenergic agonists in hybrid catfish

USDA-ARS?s Scientific Manuscript database

Ractopamine hydrochloride (RH) is a potent ß-adrenergic agonist that has been used in some species of fish to improve growth performance and dress out characteristics. While this metabolic modifier has been shown to have positive effects on growth of fish, little research has focused on the mechani...

Behavioral Characteristics of "Favorite" Coaches: Implications for Coach Education

ERIC Educational Resources Information Center

Stewart, Craig; Owens, Lynn

2011-01-01

The purpose of this paper was to use athletes' and former athletes' memories of their favorite coach to improve coach education curriculum. Player preferences of coaching behavior can affect both their attitudes toward their sport experiences and team performance. By identifying positive coaching behaviors as recalled by athletes, coach educators…

The 3P Learning Model

ERIC Educational Resources Information Center

Chatti, Mohamed Amine; Jarke, Matthias; Specht, Marcus

2010-01-01

Recognizing the failures of traditional Technology Enhanced Learning (TEL) initiatives to achieve performance improvement, we need to rethink how we design new TEL models that can respond to the learning requirements of the 21st century and mirror the characteristics of knowledge and learning which are fundamentally personal, social, distributed,…

Management Strategies for Complex Adaptive Systems: Sensemaking, Learning, and Improvisation

ERIC Educational Resources Information Center

McDaniel, Reuben R., Jr.

2007-01-01

Misspecification of the nature of organizations may be a major reason for difficulty in achieving performance improvement. Organizations are often viewed as machine-like, but complexity science suggests that organizations should be viewed as complex adaptive systems. I identify the characteristics of complex adaptive systems and give examples of…

Apollo oxygen tank stratification analysis, volume 2

NASA Technical Reports Server (NTRS)

Barton, J. E.; Patterson, H. W.

1972-01-01

An analysis of flight performance of the Apollo 15 cryogenic oxygen tanks was conducted with the variable grid stratification math model developed earlier in the program. Flight conditions investigated were the CMP-EVA and one passive thermal control period which exhibited heater temperature characteristics not previously observed. Heater temperatures for these periods were simulated with the math model using flight acceleration data. Simulation results (heater temperature and tank pressure) compared favorably with the Apollo 15 flight data, and it was concluded that tank performance was nominal. Math model modifications were also made to improve the simulation accuracy. The modifications included the addition of the effects of the tank wall thermal mass and an improved system flow distribution model. The modifications improved the accuracy of simulated pressure response based on comparisons with flight data.

Effect of matching between the magnetic field and channel length on the performance of low sputtering Hall thrusters

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Boyang, Jia; Sun, Hezhi; Wei, Liqiu; Peng, Wuji; Li, Peng; Yu, Daren

2018-02-01

Discharge characteristics of a non-wall-loss Hall thruster were studied under different channel lengths using a design based on pushing a magnetic field through a double permanent magnet ring. The effect of different magnetic field intensities and channel lengths on ionization, efficiency, and plume divergence angle were studied. The experimental results show that propellant utilization is improved for optimal matching between the magnetic field and channel length. While matching the magnetic field and channel length, the ionization position of the neutral gas changes. The ion flow is effectively controlled, allowing the thrust force, specific impulse, and efficiency to be improved. Our study shows that the channel length is an important design parameter to consider for improving the performance of non-wall-loss Hall thrusters.

Organizational performance impacting patient satisfaction in Ontario hospitals: a multilevel analysis.

PubMed

Koné Péfoyo, Anna J; Wodchis, Walter P

2013-12-05

Patient satisfaction in health care constitutes an important component of organizational performance in the hospital setting. Satisfaction measures have been developed and used to evaluate and improve hospital performance, quality of care and physician practice. In order to direct improvement strategies, it is necessary to evaluate both individual and organizational factors that can impact patients' perception of care. The study aims were to determine the dimensions of patient satisfaction, and to analyze the individual and organizational determinants of satisfaction dimensions in hospitals. We used patient and hospital survey data as well as administrative data collected for a 2008 public hospital report in Ontario, Canada. We evaluated the clustering of patient survey items with exploratory factor analysis and derived plausible dimensions of satisfaction. A two-level multivariate model was fitted to analyze the determinants of satisfaction. We found eight satisfaction factors, with acceptable to good level of loadings and good reliability. More than 95% of variation in patient satisfaction scores was attributable to patient-level variation, with less than 5% attributable to hospital-level variation. The hierarchical models explain 5 to 17% of variation at the patient level and up to 52% of variation between hospitals. Individual patient characteristics had the strongest association with all dimensions of satisfaction. Few organizational performance indicators are associated with patient satisfaction and significant determinants differ according to the satisfaction dimension. The research findings highlight the importance of adjusting for both patient-level and organization-level characteristics when evaluating patient satisfaction. Better understanding and measurement of organization-level activities and processes associated with patient satisfaction could contribute to improved satisfaction ratings and care quality.

Primary and Secondary Lithium Batteries Capable of Operating at Low Temperatures for Planetary Exploration

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; West, W. C.; Brandon, E. J.

2011-01-01

Objectives and Approach: (1) Develop advanced Li ]ion electrolytes that enable cell operation over a wide temperature range (i.e., -60 to +60 C). Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (2) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (3) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

Potential of hydrogen fuel for future air transportation systems.

NASA Technical Reports Server (NTRS)

Small, W. J.; Fetterman, D. E.; Bonner, T. F., Jr.

1973-01-01

Recent studies have shown that hydrogen fuel can yield spectacular improvements in aircraft performance in addition to its more widely discussed environmental advantages. The characteristics of subsonic, supersonic, and hypersonic transport aircraft using hydrogen fuel are discussed, and their performance and environmental impact are compared to that of similar aircraft using conventional fuel. The possibilities of developing hydrogen-fueled supersonic and hypersonic vehicles with sonic boom levels acceptable for overland flight are also explored.

The Relationship between Environmental Quality of School Facilities and Student Performance. Energy Smart Schools: Opportunities To Save Money, Save Energy and Improve Student Performance. A Congressional Briefing to the U.S. House of Representatives Committee on Science.

ERIC Educational Resources Information Center

Lackney, Jeffery A.

Congressional testimony is presented concerning school buildings and their connection to student health, behavior, and learning, including a review of selected empirical studies conducted over the past 30 years showing an explicit relationship between physical characteristics of school buildings and educational outcomes. The factors responsible…

Performance of maleated castor oil based plasticizer on rubber: rheology and curing characteristic studies

NASA Astrophysics Data System (ADS)

Indrajati, I. N.; Dewi, I. R.

2017-07-01

The objective of this study was to evaluate the performance of maleated castor oil (MACO) as plasticizer on natural rubber (NR), ethylene propylene diene monomer (EPDM), and nitrile butadiene rubber (NBR). The parameter studied were involving rheological, curing and swelling properties. The MACOs were prepared by an esterification reaction between castor oil (CO) and maleic anhydride (MAH) with the help of xylene as water entrainer to improve water removal. Resulting oils then applied as a plasticizer in each of those rubbers within a fixed loading of 5 phr. Comparison has been made to evaluate the performance of MACO and conventional plasticizer (paraffinic oil for NR and EPDM, DOP for NBR) on each rubber. Rheology, curing characteristic and swelling of each rubber were studied. The results showed that rubber (NR/EPDM/NBR) plasticized with MACO had given similar flow characteristic to conventional plasticizers. MACO exhibited slow curing, confirmed by higher t90, but the scorch safety was of the same magnitude. MAH loading tended to decrease the flow properties and curing rate, while scorch time (ts2) was independent.

Performance characteristics of a conformal ultra-wideband multilayer applicator (CUMLA) for hyperthermia in veterinary patients: a pilot evaluation of its use in the adjuvant treatment of non-resectable tumours.

PubMed

Smrkovski, O A; Koo, Y; Kazemi, R; Lembcke, L M; Fathy, A; Liu, Q; Phillips, J C

2013-03-01

Performance and clinical characteristics of a novel hyperthermia antenna operating at 434 MHz were evaluated for the adjuvant treatment of locally advanced superficial tumours in cats, dogs and horses. Electromagnetic simulations were performed to determine electric field characteristics and compared to simulations for a flat microwave antenna with similar dimensions. Simulation results show a reduced skin surface and backfield irradiation and improved directional irradiation (at broadside) compared to a flat antenna. Radiated power and penetration is notably increased with a penetration depth of 4.59 cm compared to 2.74 cm for the flat antenna. Clinical use of the antenna was then evaluated in six animals with locoregionally advanced solid tumours receiving adjuvant chemotherapy. During clinical applications, therapeutic temperatures were achieved at depths ≥4 cm. Objective responses were seen in all patients; tissue toxicity in one case limited further therapy. This antenna provides compact, efficient, focused and deep-penetrating clinical hyperthermia for the treatment of solid tumours in veterinary patients. © 2011 Blackwell Publishing Ltd.

CF6 jet engine performance improvement: New fan

NASA Technical Reports Server (NTRS)

Fasching, W. A.

1980-01-01

As part of the NASA sponsored engine component improvement program, and fan package was developed to reduce fuel consumption in current CF6 turbofan aircraft engine. The new fan package consist of an improved fan blade, reduced fan tip clearance due to a fan case stiffener, and a smooth fan casing tip shroud. CF6 engine performance and acoustic tests demonstrated the predicted 1.8% improvement in cruise sfc without an increase in engine noise. Power management thrust/fan speed characteristics were defined. Mechanical and structural integrity was demonstrated in model fan rotor photoelastic stress tests, full-size fan blade bench fatigue tests, and CF6 engine bird ingestion, crosswind, and cyclic endurance tests. The fan was certified in the CF6-500c2/E2 engines and is in commerical service on the Boeing 747-200, Douglas DC-10-30, and Atrbus industrie A300B aircraft.

Improved Saturation Performance in High Speed Waveguide Photodetectors at 1.3 ??sing an Asymmetric InA1GaAs/InGaAsP Structure

NASA Technical Reports Server (NTRS)

Vang, T. A.; Davis, L.; Keo, S.; Forouhar, S. F.

1996-01-01

Waveguide photodetector (WGPD) results have recently been presented demonstrating the very large bandwidth-efficiency product potential of these devices. Improved saturation and linearity characteristics are realized in waveguide p-i-n photodetectors at 1.3 ??y using an asymmetric cladding structure with InA1GaAs/InGaAsP in the anode and InGaAsP in the cathode.

Structure of energy consumption and improving open-pit dump truck efficiency

NASA Astrophysics Data System (ADS)

Koptev, V. Yu; Kopteva, A. V.

2017-10-01

This paper studies the dynamics of the improvement of wheel type transport vehicles environmental and energy performance in open-pit mines. The paper discloses characteristics of the gas turbine engine with capacity of 1250 hp, mounted on tanks, and technical-economic calculations, confirming reasonability of their use in open-pit dump trucks with the 120 …130-ton loading capacity. The general layout scheme of mechanical transmission with the gas turbine engine is shown.

Evaluation and Improvement of Eddy Current Position Sensors in Magnetically Suspended Flywheel Systems

NASA Technical Reports Server (NTRS)

Dever, Timothy P.; Palazzolo, Alan B.; Thomas, Erwin M., III; Jansen, Ralph H.; McLallin, Kerry (Technical Monitor); Soeder, James (Technical Monitor)

2001-01-01

Eddy current position sensor performance is evaluated for use in a high-speed flywheel development system. The flywheel utilizes a five axis active magnetic bearing system. The eddy current sensors are used for position feedback for the bearing controller. Measured characteristics include sensitivity to multiple target materials and susceptibility to noise from the magnetic bearings and from sensor-to-sensor crosstalk. Improvements in axial sensor configuration and techniques for noise reduction are described.

Improved multi-stage neonatal seizure detection using a heuristic classifier and a data-driven post-processor.

PubMed

Ansari, A H; Cherian, P J; Dereymaeker, A; Matic, V; Jansen, K; De Wispelaere, L; Dielman, C; Vervisch, J; Swarte, R M; Govaert, P; Naulaers, G; De Vos, M; Van Huffel, S

2016-09-01

After identifying the most seizure-relevant characteristics by a previously developed heuristic classifier, a data-driven post-processor using a novel set of features is applied to improve the performance. The main characteristics of the outputs of the heuristic algorithm are extracted by five sets of features including synchronization, evolution, retention, segment, and signal features. Then, a support vector machine and a decision making layer remove the falsely detected segments. Four datasets including 71 neonates (1023h, 3493 seizures) recorded in two different university hospitals, are used to train and test the algorithm without removing the dubious seizures. The heuristic method resulted in a false alarm rate of 3.81 per hour and good detection rate of 88% on the entire test databases. The post-processor, effectively reduces the false alarm rate by 34% while the good detection rate decreases by 2%. This post-processing technique improves the performance of the heuristic algorithm. The structure of this post-processor is generic, improves our understanding of the core visually determined EEG features of neonatal seizures and is applicable for other neonatal seizure detectors. The post-processor significantly decreases the false alarm rate at the expense of a small reduction of the good detection rate. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Development and evaluation of a new alcohol-based surgical hand scrub formulation with persistent antimicrobial characteristics and brushless application.

PubMed

Hobson, D W; Woller, W; Anderson, L; Guthery, E

1998-10-01

Since the introduction in the 1970s of surgical hand scrub formulations that contain 4% chlorhexidine gluconate (CHG), new surgical scrub formulations that have improved efficacy, persistence, or significantly improved use characteristics have not been forthcoming. In addition, the manufacturer's labeling for popular hand scrub products generally requires scrub times in excess of 6 minutes, whereas current practical needs call for products with substantially shorter scrub times. A new alcohol-based surgical scrub formulation, which has ingredients that provide emollient, surfactant, and antimicrobial persistence characteristics to complement the rapid and broad-spectrum antiseptic qualities of alcohol, has been developed in an effort to address these current practical needs. The relative efficacy of a new alcohol-based surgical scrub formulation that contains ingredients that provide surfactant and antimicrobial persistence characteristics was compared with that of commercial 4% CHG and 7.5% povidone iodine (PVPI) formulations with use of human subjects. Hand antimicrobial count sampling was performed by using standardized "glove juice" methodology. The efficacy and persistence results of the new formulation showed statistically significant improvement over both CHG and PVPI at a substantially lessened scrub time (3 minutes). In addition, use of the new formulation without a scrub brush produced results statistically similar to 3-minute applications with either a brush or a sponge. The new alcohol-based formulation demonstrates promise as a new surgical hand scrub formulation with antimicrobial and use characteristics that are significantly improved over current CHG and PVPI formulations. These studies demonstrate the suitability of this formulation for use as a surgical hand scrub and for brushless application.

Valorization of genetic variability for the qualitative improvement of autochthonous grape cultivars of Cirò's terroir through the self-fertilization.

PubMed

Meneghetti, Stefano; Gaiotti, Federica; Giust, Mirella; Belfiore, Nicola; Tomasi, Diego

2015-03-01

This study uses PCR-derived marker systems to investigate the genetic differences of 22 grapevine accessions obtained through a self-fertilization program using Gaglioppo and Magliocco dolce. The aim of the study was to improve some qualitative parameters, while preserving the adaptive characteristics of these two cultivars to the adverse environmental conditions of the Calabria region (southern Italy). These two Calabrian grapevines have been cultivated within a restricted area and have been placed under a strong anthropic pressure which has limited their phenotypical variability with no selection of higher performant biotypes. Therefore, to have accessions with improved qualitative traits, a program of genetic improvement based on the self-fertilization of Gaglioppo and Magliocco dolce cultivars was performed in 1998, producing 3,122 accessions. Selection cycles were performed in 14 years. A first selection cycle (1998-2000), based on visual inspection of vegetative traits, selected 1,320 accessions, planted in an experimental vineyard in 2000. A second selection cycle (2000-2008), based on phenotypic traits, sanitary aspects, and chemical composition of the grapes, selected 42 accessions, planted in a new experimental vineyard in 2008. A final selection cycle (2008-2012), produced 22 accessions (virus free), with the best agronomic, sanitary, and qualitative aspects: two accessions obtained from Gaglioppo have been selected by color characteristics (i.e., anthocyanin total content and stability); 20 genotypes obtained from Magliocco dolce had a better macro-composition of the grape (i.e., good sugar content with a balanced acidity). SSR analyses were performed to check the self-fertilization process. The study of genetic differences between accessions was performed by AFLPs, SAMPLs, and M-AFLPs. The application of the above-mentioned techniques allowed both to discriminate molecularly the 22 accessions grouped these accessions according to their genetic similarity. The self-fertilization approach has enabled improvement in the quality of the grapes, while preserving the high degree of adaptation to the environment of these two native Calabrian cultivars in southern Italy.

Nanochips of Tantalum Oxide Nanodots as artificial-microenvironments for monitoring Ovarian cancer progressiveness

NASA Astrophysics Data System (ADS)

Dhawan, Udesh; Wang, Ssu-Meng; Chu, Ying Hao; Huang, Guewha S.; Lin, Yan Ren; Hung, Yao Ching; Chen, Wen Liang

2016-08-01

Nanotopography modulates cell characteristics and cell behavior. Nanotopological cues can be exploited to investigate the in-vivo modulation of cell characteristics by the cellular microenvironment. However, the studies explaining the modulation of tumor cell characteristics and identifying the transition step in cancer progressiveness are scarce. Here, we engineered nanochips comprising of Tantalum oxide nanodot arrays of 10, 50, 100 and 200 nm as artificial microenvironments to study the modulation of cancer cell behavior. Clinical samples of different types of Ovarian cancer at different stages were obtained, primary cultures were established and then seeded on different nanochips. Immunofluorescence (IF) was performed to compare the morphologies and cell characteristics. Indices corresponding to cell characteristics were defined. A statistical comparison of the cell characteristics in response to the nanochips was performed. The cells displayed differential growth parameters. Morphology, Viability, focal adhesions, microfilament bundles and cell area were modulated by the nanochips which can be used as a measure to study the cancer progressiveness. The ease of fabrication of nanochips ensures mass-production. The ability of the nanochips to act as artificial microenvironments and modulate cell behavior may lead to further prospects in the markerless monitoring of the progressiveness and ultimately, improving the prognosis of Ovarian cancer.

Limitations of and Barriers to Using Performance Measurement: Purchasers' Perspectives

PubMed Central

Ginsberg, Caren; Sheridan, Samantha

2001-01-01

Although health plan performance data are becoming increasingly more available, many purchasers are still not using these data to make their purchasing decisions. In this article, we review barriers that private purchasers face to using performance data. In addition, we consider the effects of the larger health care purchasing environment and employers' quality improvement activities on their use of the data. We conclude that a variety of factors, including trends, the health care purchasing environment, characteristics of firms, and problems with performance data and their presentation to users create barriers to incorporating this information into health care decisionmaking. PMID:25372184

Home Rx: The Health Benefits of Home Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, Jonathan; Jacobs, David; Reddy, Amanda

Evidence in a new, groundbreaking U.S. Department of Energy report, Home Rx: The Health Benefits of Home Performance, shows that home performance upgrades can improve the quality of a home’s indoor environment by reducing the prevalence of harmful indoor air pollutants and contaminants. Until recently, no systematic review of this evidence had been conducted, limiting full understanding of the link between home performance and health. This new report summarizes current knowledge and identifies research gaps. The design characteristics and results of each of the 40 studies considered in the report are summarized in a searchable matrix.

Analysis of On-board Hazard Detection and Avoidance for Safe Lunar Landing

NASA Technical Reports Server (NTRS)

Johnson, Andrew E.; Huertas, Andres; Werner, Robert A.; Montgomery, James F.

2008-01-01

Landing hazard detection and avoidance technology is being pursued within NASA to improve landing safety and increase access to sites of interest on the lunar surface. The performance of a hazard detection and avoidance system depends on properties of the terrain, sensor performance, algorithm design, vehicle characteristics and the overall all guidance navigation and control architecture. This paper analyzes the size of the region that must be imaged, sensor performance parameters and the impact of trajectory angle on hazard detection performance. The analysis shows that vehicle hazard tolerance is the driving parameter for hazard detection system design.

Pacing and Self-regulation: Important Skills for Talent Development in Endurance Sports.

PubMed

Elferink-Gemser, Marije T; Hettinga, Florentina J

2017-07-01

Pacing has been characterized as a multifaceted goal-directed process of decision making in which athletes need to decide how and when to invest their energy during the race, a process essential for optimal performance. Both physiological and psychological characteristics associated with adequate pacing and performance are known to develop with age. Consequently, the multifaceted skill of pacing might be under construction throughout adolescence, as well. Therefore, the authors propose that the complex skill of pacing is a potential important performance characteristic for talented youth athletes that needs to be developed throughout adolescence. To explore whether pacing is a marker for talent and how talented athletes develop this skill in middle-distance and endurance sports, they aim to bring together literature on pacing and literature on talent development and self-regulation of learning. Subsequently, by applying the cyclical process of self-regulation to pacing, they propose a practical model for the development of performance in endurance sports in youth athletes. Not only is self-regulation essential throughout the process of reaching the long-term goal of athletic excellence, but it also seems crucial for the development of pacing skills within a race and the development of a refined performance template based on previous experiences. Coaches and trainers are advised to incorporate pacing as a performance characteristic in their talent-development programs by stimulating their athletes to reflect, plan, monitor, and evaluate their races on a regular basis to build performance templates and, as such, improve their performance.

Video-signal improvement using comb filtering techniques.

NASA Technical Reports Server (NTRS)

Arndt, G. D.; Stuber, F. M.; Panneton, R. J.

1973-01-01

Significant improvement in the signal-to-noise performance of television signals has been obtained through the application of comb filtering techniques. This improvement is achieved by removing the inherent redundancy in the television signal through linear prediction and by utilizing the unique noise-rejection characteristics of the receiver comb filter. Theoretical and experimental results describe the signal-to-noise ratio and picture-quality improvement obtained through the use of baseband comb filters and the implementation of a comb network as the loop filter in a phase-lock-loop demodulator. Attention is given to the fact that noise becomes correlated when processed by the receiver comb filter.

Impact of Contextual Factors and Substance Characteristics on Perspectives toward Cognitive Enhancement

PubMed Central

Sattler, Sebastian; Forlini, Cynthia; Racine, Éric; Sauer, Carsten

2013-01-01

Enhancing cognitive performance with substances–especially prescription drugs–is a fiercely debated topic among scholars and in the media. The empirical basis for these discussions is limited, given that the actual nature of factors that influence the acceptability of and willingness to use cognitive enhancement substances remains unclear. In an online factorial survey, contextual and substance-specific characteristics of substances that improve academic performance were varied experimentally and presented to respondents. Students in four German universities rated their willingness to use and moral acceptance of different substances for cognitive enhancement. We found that the overall willingness to use performance enhancing substances is low. Most respondents considered the use of these substances as morally unacceptable. Situational influences such as peer pressure, policies concerning substance use, relative performance level of peers, but also characteristics of the substance, such as perceptions of substance safety, shape the willingness and acceptability of using a substance to enhance academic performance. Among the findings is evidence of a contagion effect meaning that the willingness was higher when the respondents have more CE drug users in their social network. We also found deterrence effects from strong side effects of using the substance, as well as from policy regulations and sanctions. Regulations might activate social norms against usage and sanctions can be seen as costly to users. Moreover, enhancement substances seem to be most tempting to low performers to catch up with others compared to high performers. By identifying contextual factors and substance characteristics influencing the willingness and acceptability of cognitive enhancers, policy approaches could consider these insights to better manage the use of such substances. PMID:23940757

Improving Physical Task Performance with Counterfactual and Prefactual Thinking.

PubMed

Hammell, Cecilia; Chan, Amy Y C

2016-01-01

Counterfactual thinking (reflecting on "what might have been") has been shown to enhance future performance by translating information about past mistakes into plans for future action. Prefactual thinking (imagining "what might be if…") may serve a greater preparative function than counterfactual thinking as it is future-orientated and focuses on more controllable features, thus providing a practical script to prime future behaviour. However, whether or not this difference in hypothetical thought content may translate into a difference in actual task performance has been largely unexamined. In Experiment 1 (n = 42), participants performed trials of a computer-simulated physical task, in between which they engaged in either task-related hypothetical thinking (counterfactual or prefactual) or an unrelated filler task (control). As hypothesised, prefactuals contained more controllable features than counterfactuals. Moreover, participants who engaged in either form of hypothetical thinking improved significantly in task performance over trials compared to participants in the control group. The difference in thought content between counterfactuals and prefactuals, however, did not yield a significant difference in performance improvement. Experiment 2 (n = 42) replicated these findings in a dynamic balance task environment. Together, these findings provide further evidence for the preparatory function of counterfactuals, and demonstrate that prefactuals share this same functional characteristic.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akcakaya, Murat; Nehorai, Arye; Sen, Satyabrata

Most existing radar algorithms are developed under the assumption that the environment (clutter) is stationary. However, in practice, the characteristics of the clutter can vary enormously depending on the radar-operational scenarios. If unaccounted for, these nonstationary variabilities may drastically hinder the radar performance. Therefore, to overcome such shortcomings, we develop a data-driven method for target detection in nonstationary environments. In this method, the radar dynamically detects changes in the environment and adapts to these changes by learning the new statistical characteristics of the environment and by intelligibly updating its statistical detection algorithm. Specifically, we employ drift detection algorithms to detectmore » changes in the environment; incremental learning, particularly learning under concept drift algorithms, to learn the new statistical characteristics of the environment from the new radar data that become available in batches over a period of time. The newly learned environment characteristics are then integrated in the detection algorithm. Furthermore, we use Monte Carlo simulations to demonstrate that the developed method provides a significant improvement in the detection performance compared with detection techniques that are not aware of the environmental changes.« less

Stochastic seismic response of building with super-elastic damper

NASA Astrophysics Data System (ADS)

Gur, Sourav; Mishra, Sudib Kumar; Roy, Koushik

2016-05-01

Hysteretic yield dampers are widely employed for seismic vibration control of buildings. An improved version of such damper has been proposed recently by exploiting the superelastic force-deformation characteristics of the Shape-Memory-Alloy (SMA). Although a number of studies have illustrated the performance of such damper, precise estimate of the optimal parameters and performances, along with the comparison with the conventional yield damper is lacking. Presently, the optimal parameters for the superelastic damper are proposed by conducting systematic design optimization, in which, the stochastic response serves as the objective function, evaluated through nonlinear random vibration analysis. These optimal parameters can be employed to establish an initial design for the SMA-damper. Further, a comparison among the optimal responses is also presented in order to assess the improvement that can be achieved by the superelastic damper over the yield damper. The consistency of the improvements is also checked by considering the anticipated variation in the system parameters as well as seismic loading condition. In spite of the improved performance of super-elastic damper, the available variant of SMA(s) is quite expensive to limit their applicability. However, recently developed ferrous SMA are expected to offer even superior performance along with improved cost effectiveness, that can be studied through a life cycle cost analysis in future work.

Design of piezoelectric probe for measurement of longitudinal and shear components of elastic wave

NASA Astrophysics Data System (ADS)

Aoyanagi, Masafumi; Wakatsuki, Naoto; Mizutani, Koichi; Ebihara, Tadashi

2017-07-01

We focus on ultrasonic probes for nondestructive tests and evaluation. Transient characteristics of probes are important for nondestructive tests such as the pulse echo method. We previously reported the principle of measurement using a piezoelectric probe with triaxial sensitivities. In the results, it was calculated that the probe could transmit and receive particle displacement which contains normal and tangential components. It was confirmed that the probe had sensitivities in triaxial directions. However, its performance in terms of frequency and transient characteristics has not been evaluated. The purpose of this study is to design a probe by changing its shape to obtain better performance. The transient characteristics of probes in longitudinal and shear driving were evaluated by the inverse Fourier transformation of frequency responses of longitudinal and shear components, using the two-dimensional finite element method. As a result, the sensitivities at the dips of frequency characteristics increased when using our probe compared with those measured using conventional probes in longitudinal and shear driving. Hence, the performance in terms of the frequency response was improved by more than 3 dB under the conditions in this simulation. Also, the pulse width of impulse response was decreased by half compared with that of probes with conventional shapes.

Progress in the Development of CdZnTe Unipolar Detectors for Different Anode Geometries and Data Corrections

PubMed Central

Zhang, Qiushi; Zhang, Congzhe; Lu, Yanye; Yang, Kun; Ren, Qiushi

2013-01-01

CdZnTe detectors have been under development for the past two decades, providing good stopping power for gamma rays, lightweight camera heads and improved energy resolution. However, the performance of this type of detector is limited primarily by incomplete charge collection problems resulting from charge carriers trapping. This paper is a review of the progress in the development of CdZnTe unipolar detectors with some data correction techniques for improving performance of the detectors. We will first briefly review the relevant theories. Thereafter, two aspects of the techniques for overcoming the hole trapping issue are summarized, including irradiation direction configuration and pulse shape correction methods. CdZnTe detectors of different geometries are discussed in detail, covering the principal of the electrode geometry design, the design and performance characteristics, some detector prototypes development and special correction techniques to improve the energy resolution. Finally, the state of art development of 3-D position sensing and Compton imaging technique are also discussed. Spectroscopic performance of CdZnTe semiconductor detector will be greatly improved even to approach the statistical limit on energy resolution with the combination of some of these techniques. PMID:23429509

JT8D engine performance retention

NASA Technical Reports Server (NTRS)

James, A. D.; Weisel, D. R.

1981-01-01

The attractive performance retention characteristics of the JT8D engine are described. Because of its moderate bypass ratio and turbine temperature, and stiff structural design, the performance retention versus flight cycles of the JT8D engine sets a standard that is difficult for other engines to equal. In addition, the significant benefits of refurbishment of the JT8D engine are presented. Cold section refurbishment offers thrust specific fuel consumption improvements of up to 2 percent and payback in less than a year, making a very attractive investment option for the airlines.

[Familial characteristics and self-perceived health among female and male primary care physicians in Andalusia (Spain)].

PubMed

Delgado, Ana; Saletti-Cuesta, Lorena; López-Fernández, Luis Andrés; Toro-Cárdenas, Silvia

2013-01-01

To determine the relationships between a group of professional and family characteristics and the components of physical and mental health in female and male primary care physicians working in health centers in Andalusia (Spain). A descriptive, cross-sectional, multicenter study was performed. The population consisted of urban health centers in Andalusia and their physicians. The sample comprised 88 health centers and 500 physicians. Measurements consisted of sex, age, professional characteristics (postgraduate training in family medicine, position of health center manager, accreditation as a residents' tutor, and workload based on patient quota and the mean number of patients/day); family responsibilities, defined by two dimensions of the family-work relationship (support overload-family support deficit and family-work conflict); and perceived physical and mental health. The data source was a self-administered questionnaire sent by surface mail. Multiple regression analyses were performed for physical and mental health for the whole sample and by gender. Responses were obtained from 368 physicians (73.6%). Mental health was worse in female physicians than in male physicians; no differences were found between genders in physical health. The family-work conflict was associated with physical and mental health in physicians of both genders. Physical health deteriorated with increasing age in both genders, improved in the female tutors of residents, and decreased with increasing family-work conflict in male physicians. Mental health decreased with increasing housework on the weekends and with family-work conflict in both genders. In male physicians, mental health deteriorated with postgraduate training in family medicine and improved if they were health center managers. Workload and professional characteristics have little relationship with the health of primary care physicians. Family characteristics play a greater role. Copyright © 2012 SESPAS. Published by Elsevier Espana. All rights reserved.

Influence of physician factors on the effectiveness of a continuing medical education intervention.

PubMed

Flores, Sergio; Reyes, Hortensia; Perez-Cuevas, Ricardo

2006-01-01

Continuing medical education (CME) is essential for improving the quality of care in primary health care settings. This study's objective was to determine how the characteristics of family physicians influenced the effectiveness of a multifaceted CME intervention to improve the management of acute respiratory infection (ARI) or type 2 diabetes (DM2). A secondary analysis was conducted based on data from 121 family physicians, who participated in the educational intervention study. The outcome variable was positive change in physician's performance for treatment of ARI or DM2. The exposure variable was multifaceted CME intervention. Independent variables were professional physicians and organizational characteristics. Analysis included log binomial regression modeling. Factors influencing positive change included, for ARI, participation in the CME intervention and medical director interested in that condition and for DM2, participation in the CME intervention, medical director interested in DM2, and being a teacher. Physicians' characteristics and organizational environment influence the effectiveness of educational intervention and are therefore relevant to the implementation of CME strategies.

Accurate modeling of switched reluctance machine based on hybrid trained WNN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Shoujun, E-mail: sunnyway@nwpu.edu.cn; Ge, Lefei; Ma, Shaojie

2014-04-15

According to the strong nonlinear electromagnetic characteristics of switched reluctance machine (SRM), a novel accurate modeling method is proposed based on hybrid trained wavelet neural network (WNN) which combines improved genetic algorithm (GA) with gradient descent (GD) method to train the network. In the novel method, WNN is trained by GD method based on the initial weights obtained per improved GA optimization, and the global parallel searching capability of stochastic algorithm and local convergence speed of deterministic algorithm are combined to enhance the training accuracy, stability and speed. Based on the measured electromagnetic characteristics of a 3-phase 12/8-pole SRM, themore » nonlinear simulation model is built by hybrid trained WNN in Matlab. The phase current and mechanical characteristics from simulation under different working conditions meet well with those from experiments, which indicates the accuracy of the model for dynamic and static performance evaluation of SRM and verifies the effectiveness of the proposed modeling method.« less

Biopharmaceutical considerations and characterizations in development of colon targeted dosage forms for inflammatory bowel disease.

PubMed

Malayandi, Rajkumar; Kondamudi, Phani Krishna; Ruby, P K; Aggarwal, Deepika

2014-04-01

Colon targeted dosage forms have been extensively studied for the localized treatment of inflammatory bowel disease. These dosage forms not only improve the therapeutic efficacy but also reduce the incidence of adverse drug reactions and hence improve the patient compliance. However, complex and highly variable gastro intestinal physiology limits the clinical success of these dosage forms. Biopharmaceutical characteristics of these dosage forms play a key role in rapid formulation development and ensure the clinical success. The complexity in product development and clinical success of colon targeted dosage forms are based on the biopharmaceutical characteristics such as physicochemical properties of drug substances, pharmaceutical characteristics of dosage form, physiological conditions and pharmacokinetic properties of drug substances as well as drug products. Various in vitro and in vivo techniques have been employed in past to characterize the biopharmaceutical properties of colon targeted dosage forms. This review focuses on the factors influencing the biopharmaceutical performances of the dosage forms, in vitro characterization techniques and in vivo studies.

Determinants of success in Shared Savings Programs: An analysis of ACO and market characteristics.

PubMed

Ouayogodé, Mariétou H; Colla, Carrie H; Lewis, Valerie A

2017-03-01

Medicare's Accountable Care Organization (ACO) programs introduced shared savings to traditional Medicare, which allow providers who reduce health care costs for their patients to retain a percentage of the savings they generate. To examine ACO and market factors associated with superior financial performance in Medicare ACO programs. We obtained financial performance data from the Centers for Medicare and Medicaid Services (CMS); we derived market-level characteristics from Medicare claims; and we collected ACO characteristics from the National Survey of ACOs for 215 ACOs. We examined the association between ACO financial performance and ACO provider composition, leadership structure, beneficiary characteristics, risk bearing experience, quality and process improvement capabilities, physician performance management, market competition, CMS-assigned financial benchmark, and ACO contract start date. We examined two outcomes from Medicare ACOs' first performance year: savings per Medicare beneficiary and earning shared savings payments (a dichotomous variable). When modeling the ACO ability to save and earn shared savings payments, we estimated positive regression coefficients for a greater proportion of primary care providers in the ACO, more practicing physicians on the governing board, physician leadership, active engagement in reducing hospital re-admissions, a greater proportion of disabled Medicare beneficiaries assigned to the ACO, financial incentives offered to physicians, a larger financial benchmark, and greater ACO market penetration. No characteristic of organizational structure was significantly associated with both outcomes of savings per beneficiary and likelihood of achieving shared savings. ACO prior experience with risk-bearing contracts was positively correlated with savings and significantly increased the likelihood of receiving shared savings payments. In the first year, performance is quite heterogeneous, yet organizational structure does not consistently predict performance. Organizations with large financial benchmarks at baseline have greater opportunities to achieve savings. Findings on prior risk bearing suggest that ACOs learn over time under risk-bearing contracts. Given the lack of predictive power for organizational characteristics, CMS should continue to encourage diversity in organizational structures for ACO participants, and provide alternative funding and risk bearing mechanisms to continue to allow a diverse group of organizations to participate. III. Copyright © 2016 Elsevier Inc. All rights reserved.

Determinants of Success in Shared Savings Programs: An Analysis of ACO and Market Characteristics

PubMed Central

Colla, Carrie H.; Lewis, Valerie A.

2016-01-01

Background Medicare’s Accountable Care Organization (ACO) programs introduced shared savings to traditional Medicare, which allow providers who reduce health care costs for their patients to retain a percentage of the savings they generate. Objective To examine ACO and market factors associated with superior financial performance in Medicare ACO programs. Methods We obtained financial performance data from the Centers for Medicare and Medicaid Services (CMS); we derived market-level characteristics from Medicare claims; and we collected ACO characteristics from the National Survey of ACOs for 215 ACOs. We examined the association between ACO financial performance and ACO provider composition, leadership structure, beneficiary characteristics, risk bearing experience, quality and process improvement capabilities, physician performance management, market competition, CMS-assigned financial benchmark, and ACO contract start date. We examined two outcomes from Medicare ACOs’ first performance year: savings per Medicare beneficiary and earning shared savings payments (a dichotomous variable). Results When modeling the ACO ability to save and earn shared savings payments, we estimated positive regression coefficients for a greater proportion of primary care providers in the ACO, more practicing physicians on the governing board, physician leadership, active engagement in reducing hospital re-admissions, a greater proportion of disabled Medicare beneficiaries assigned to the ACO, financial incentives offered to physicians, a larger financial benchmark, and greater ACO market penetration. No characteristic of organizational structure was significantly associated with both outcomes of savings per beneficiary and likelihood of achieving shared savings. ACO prior experience with risk-bearing contracts was positively correlated with savings and significantly increased the likelihood of receiving shared savings payments. Conclusions In the first year performance is quite heterogeneous, yet organizational structure does not consistently predict performance. Organizations with large financial benchmarks at baseline have greater opportunities to achieve savings. Findings on prior risk bearing suggest that ACOs learn over time under risk-bearing contracts. Implications Given the lack of predictive power for organizational characteristics, CMS should continue to encourage diversity in organizational structures for ACO participants, and provide alternative funding and risk bearing mechanisms to continue to allow a diverse group of organizations to participate. Level of evidence III PMID:27687917

Surface modification of Ni–Ti alloys for stent application after magnetoelectropolishing

PubMed Central

Musaramthota, Vishal; Munroe, Norman; Datye, Amit; Dua, Rupak; Haider, Waseem; McGoron, Anthony; Rokicki, Ryszard

2015-01-01

The constant demand for new implant materials and the multidisciplinary design approaches for stent applications have expanded vastly over the past decade. The biocompatibility of these implant materials is a function of their surface characteristics such as morphology, surface chemistry, roughness, surface charge and wettability. These surface characteristics can directly influence the material's corrosion resistance and biological processes such as endothelialization. Surface morphology affects the thermodynamic stability of passivating oxides, which renders corrosion resistance to passivating alloys. Magnetoelectropolishing (MEP) is known to alter the morphology and composition of surface films, which assist in improving corrosion resistance of Nitinol alloys. This work aims at analyzing the surface characteristics of MEP Nitinol alloys by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the alloys was determined by contact angle measurements and the mechanical properties were assessed by Nanoindentation. Improved mechanical properties were observed with the addition of alloying elements. Cyclic potentiodynamic polarization tests were performed to determine the corrosion susceptibility. Further, the alloys were tested for their cytotoxicity and cellular growth with endothelial cells. Improved corrosion resistance and cellular viability were observed with MEP surface treated alloys. PMID:25746243

Development of superconductor magnetic suspension and balance prototype facility for studying the feasibility of applying this technique to large scale aerodynamic testing

NASA Technical Reports Server (NTRS)

Zapata, R. N.; Humphris, R. R.; Henderson, K. C.

1975-01-01

The unique design and operational characteristics of a prototype magnetic suspension and balance facility which utilizes superconductor technology are described and discussed from the point of view of scalability to large sizes. The successful experimental demonstration of the feasibility of this new magnetic suspension concept of the University of Virginia, together with the success of the cryogenic wind-tunnel concept developed at Langley Research Center, appear to have finally opened the way to clean-tunnel, high-Re aerodynamic testing. Results of calculations corresponding to a two-step design extrapolation from the observed performance of the prototype magnetic suspension system to a system compatible with the projected cryogenic transonic research tunnel are presented to give an order-of-magnitude estimate of expected performance characteristics. Research areas where progress should lead to improved design and performance of large facilities are discussed.

A review on the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends.

PubMed

Damanik, Natalina; Ong, Hwai Chyuan; Tong, Chong Wen; Mahlia, Teuku Meurah Indra; Silitonga, Arridina Susan

2018-06-01

Biodiesels have gained much popularity because they are cleaner alternative fuels and they can be used directly in diesel engines without modifications. In this paper, a brief review of the key studies pertaining to the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends, exhaust aftertreatment systems, and low-temperature combustion technology is presented. In general, most biodiesel blends result in a significant decrease in carbon monoxide and total unburned hydrocarbon emissions. There is also a decrease in carbon monoxide, nitrogen oxide, and total unburned hydrocarbon emissions while the engine performance increases for diesel engines fueled with biodiesels blended with nano-additives. The development of automotive technologies, such as exhaust gas recirculation systems and low-temperature combustion technology, also improves the thermal efficiency of diesel engines and reduces nitrogen oxide and particulate matter emissions.

Improving L2 Reading Comprehension through Emotionalized Dynamic Assessment Procedures.

PubMed

Abdolrezapour, Parisa

2017-06-01

The paper reports a study on an emotionally-loaded dynamic assessment procedure used with Iranian EFL learners. It focuses on the effect of using emotional intelligence characteristics (based on Goleman's framework) as a tool for motivating learners while performing reading tasks. The study with 50 intermediate learners aged 12-15 used three modalities: a control group, which was taught under institute's normal procedures; a comparison group, which received dynamic assessment (DA); and an experimental group, which received emotionalized dynamic assessment (EDA) procedures, in the form of an intervention focusing on characteristics of Goleman's emotional intelligence framework with the express purpose of inducing them to work with their emotions. Results showed that applying EDA procedures to reading assessment tasks made a difference in learners' level of performance in comparison to those who went through pure DA procedures who in turn performed significantly better than those who did not received DA in any form.

Improved performance characteristics of a high temperature superconductor bolometer using photo-thermoelectrical feedback

NASA Astrophysics Data System (ADS)

Kaila, M. M.; Russell, G. J.

2000-12-01

We have designed a liquid nitrogen cooled detector where a thermoelectric feedback is combined with electrothermal feedback to produce an improvement of three orders of magnitude in the response time of the detector. We have achieved this by considering a parallel resistance combination of thermoelectric and High Temperature Superconductor (HTSC) material legs of an approximate geometry 1mm /spl times/ 2 mm /spl times/ 1micron operated at 80K. One end of this thermocouple acts as the sensitive area where the radiation is absorbed. The other end remains unexposed and stays basically at substrate temperature. It is found that micron thick films in our bolometer produce characteristics very close to those found for nanometer thick films required in semiconductor detectors and Low Temperature Superconductor (LTSC) bolometers.

Improved model for detection of homogeneous production batches of electronic components

NASA Astrophysics Data System (ADS)

Kazakovtsev, L. A.; Orlov, V. I.; Stashkov, D. V.; Antamoshkin, A. N.; Masich, I. S.

2017-10-01

Supplying the electronic units of the complex technical systems with electronic devices of the proper quality is one of the most important problems for increasing the whole system reliability. Moreover, for reaching the highest reliability of an electronic unit, the electronic devices of the same type must have equal characteristics which assure their coherent operation. The highest homogeneity of the characteristics is reached if the electronic devices are manufactured as a single production batch. Moreover, each production batch must contain homogeneous raw materials. In this paper, we propose an improved model for detecting the homogeneous production batches of shipped lot of electronic components based on implementing the kurtosis criterion for the results of non-destructive testing performed for each lot of electronic devices used in the space industry.

NASA Lewis and Ohio Company Hit Hole in One

NASA Technical Reports Server (NTRS)

1998-01-01

Ben Hogan Company's Golf Ball Division, which is based in Elyria, Ohio, had developed concepts and prototypes for new golf balls but was unable to determine exact performance characteristics. Specifically, the company's R&D department wanted to measure the spin rates of experimental golf balls. After the Golf Ball Division requested assistance, researchers and technicians from the NASA Lewis Research Center went to Elyria and conducted several days worth of tests. Ben Hogan is using the test results to improve the spin characteristics of a new ball it plans to introduce to the market.

Experimental study of the operating characteristics of premixing-prevaporizing fuel/air mixing passages

NASA Technical Reports Server (NTRS)

Rohy, D. A.; Meier, J. G.

1983-01-01

Fuel spray and air flow characteristics were determined using nonintrusive (optical) measurement techniques in a fuel preparation duct. A very detailed data set was obtained at high pressures (to 10 atm) and temperatures (to 750 K). The data will be used to calibrate an analytical model which will facilitate the design of a lean premixed prevaporized combustor. This combustor has potential for achieving low pollutant emissions and low levels of flame radiation and pattern factors conductive to improved durability and performance for a variety of fuels.

Analysing organisational context: case studies on the contribution of absorptive capacity theory to understanding inter-organisational variation in performance improvement.

PubMed

Harvey, Gill; Jas, Pauline; Walshe, Kieran

2015-01-01

Organisational context is frequently cited as an important consideration when implementing and evaluating quality improvement interventions in healthcare, but limited guidance is available on which aspects of context are most influential or modifiable. This paper examines how internal and external contextual factors mediate organisational-level performance improvement through applying the knowledge-based theory of absorptive capacity (AC). Three healthcare case studies are presented. Each case is a UK National Health Service organisation that had been identified as having performance problems. Qualitative data were collected through semi-structured interviews with general and clinical managers within the organisation and members of external teams supporting or overseeing performance improvement (n=22). Interview data were analysed using an existing AC framework from the literature. The organisation with the highest AC showed the quickest and most comprehensive performance improvement. Internal characteristics including strategic priorities, processes for managing information, communication and orientation to learning and development impacted on the organisation's ability to engage successfully with external stakeholders and make use of available knowledge. This enabled the organisation to thrive despite the challenging external environment. Lower levels of AC appeared to delay or limit the improvement trajectory. Developing a more detailed and nuanced understanding of how context influences improvement is an important step towards achieving more effective and sustainable quality improvement programmes in healthcare. AC, with its focus on knowledge and organisational learning, provides a useful way to explore the relationship between context and quality improvement and represents a potentially valuable area for future research and development. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

High-performance a-IGZO thin-film transistor with conductive indium-tin-oxide buried layer

NASA Astrophysics Data System (ADS)

Ahn, Min-Ju; Cho, Won-Ju

2017-10-01

In this study, we fabricated top-contact top-gate (TCTG) structure of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) with a thin buried conductive indium-tin oxide (ITO) layer. The electrical performance of a-IGZO TFTs was improved by inserting an ITO buried layer under the IGZO channel. Also, the effect of the buried layer's length on the electrical characteristics of a-IGZO TFTs was investigated. The electrical performance of the transistors improved with increasing the buried layer's length: a large on/off current ratio of 1.1×107, a high field-effect mobility of 35.6 cm2/Vs, a small subthreshold slope of 116.1 mV/dec, and a low interface trap density of 4.2×1011 cm-2eV-1 were obtained. The buried layer a-IGZO TFTs exhibited enhanced transistor performance and excellent stability against the gate bias stress.

A framework for evaluating the formation, implementation, and performance of accountable care organizations.

PubMed

Fisher, Elliott S; Shortell, Stephen M; Kreindler, Sara A; Van Citters, Aricca D; Larson, Bridget K

2012-11-01

The implementation of accountable care organizations (ACOs), a new health care payment and delivery model designed to improve care and lower costs, is proceeding rapidly. We build on our experience tracking early ACOs to identify the major factors-such as contract characteristics; structure, capabilities, and activities; and local context-that would be likely to influence ACO formation, implementation, and performance. We then propose how an ACO evaluation program could be structured to guide policy makers and payers in improving the design of ACO contracts, while providing insights for providers on approaches to care transformation that are most likely to be successful in different contexts. We also propose key activities to support evaluation of ACOs in the near term, including tracking their formation, developing a set of performance measures across all ACOs and payers, aggregating those performance data, conducting qualitative and quantitative research, and coordinating different evaluation activities.

Otoacoustic emissions in the general adult population of Nord-Trøndelag, Norway: III. Relationships with pure-tone hearing thresholds.

PubMed

Engdahl, Bo; Tambs, Kristian; Borchgrevink, Hans M; Hoffman, Howard J

2005-01-01

This study aims to describe the association between otoacoustic emissions (OAEs) and pure-tone hearing thresholds (PTTs) in an unscreened adult population (N =6415), to determine the efficiency by which TEOAEs and DPOAEs can identify ears with elevated PTTs, and to investigate whether a combination of DPOAE and TEOAE responses improves this performance. Associations were examined by linear regression analysis and ANOVA. Test performance was assessed by receiver operator characteristic (ROC) curves. The relation between OAEs and PTTs appeared curvilinear with a moderate degree of non-linearity. Combining DPOAEs and TEOAEs improved performance. Test performance depended on the cut-off thresholds defining elevated PTTs with optimal values between 25 and 45 dB HL, depending on frequency and type of OAE measure. The unique constitution of the present large sample, which reflects the general adult population, makes these results applicable to population-based studies and screening programs.

The future scientific CCD

NASA Technical Reports Server (NTRS)

Janesick, J. R.; Elliott, T.; Collins, S.; Marsh, H.; Blouke, M. M.

1984-01-01

Since the first introduction of charge-coupled devices (CCDs) in 1970, CCDs have been considered for applications related to memories, logic circuits, and the detection of visible radiation. It is pointed out, however, that the mass market orientation of CCD development has left largely untapped the enormous potential of these devices for advanced scientific instrumentation. The present paper has, therefore, the objective to introduce the CCD characteristics to the scientific community, taking into account prospects for further improvement. Attention is given to evaluation criteria, a summary of current CCDs, CCD performance characteristics, absolute calibration tools, quantum efficiency, aspects of charge collection, charge transfer efficiency, read noise, and predictions regarding the characteristics of the next generation of silicon scientific CCD imagers.

Hydrophilic modification of polyethersulfone and its membrane characteristics

NASA Astrophysics Data System (ADS)

Liu, Haiju; Huangfu, Feng-yun; Bai, Yundong; Kong, Yuanyuan

2010-07-01

In order to enhance the hydrophilicity of PES, A series of sulfonated polyethersulfone (SPES) were readily prepared via a reaction of sulphonation which used chlorosulfonic as sulfonating agent and concentrated sulfuric acid as solvent. Sulfonation was confirmed by Fourier transform infrared spectroscopy and Thermo gravimetric analyzer. We studied forming film characteristic of SPES by phase diagram. The sulfonated PES materials were then utilized as a hydrophilic modifier for fabrication of SPES membranes. The solvent was NMP and PEG-6000 was pore-forming agent. The characteristics of membranes were studied. It was found that the surface hydrophilicity of the modified PES membranes was remarkably enhanced by contact angle. Water flux was obvious increased and antifouling performance was also improved.

Tuning Monotonic Basin Hopping: Improving the Efficiency of Stochastic Search as Applied to Low-Thrust Trajectory Optimization

NASA Technical Reports Server (NTRS)

Englander, Jacob A.; Englander, Arnold C.

2014-01-01

Trajectory optimization methods using monotonic basin hopping (MBH) have become well developed during the past decade [1, 2, 3, 4, 5, 6]. An essential component of MBH is a controlled random search through the multi-dimensional space of possible solutions. Historically, the randomness has been generated by drawing random variable (RV)s from a uniform probability distribution. Here, we investigate the generating the randomness by drawing the RVs from Cauchy and Pareto distributions, chosen because of their characteristic long tails. We demonstrate that using Cauchy distributions (as first suggested by J. Englander [3, 6]) significantly improves monotonic basin hopping (MBH) performance, and that Pareto distributions provide even greater improvements. Improved performance is defined in terms of efficiency and robustness. Efficiency is finding better solutions in less time. Robustness is efficiency that is undiminished by (a) the boundary conditions and internal constraints of the optimization problem being solved, and (b) by variations in the parameters of the probability distribution. Robustness is important for achieving performance improvements that are not problem specific. In this work we show that the performance improvements are the result of how these long-tailed distributions enable MBH to search the solution space faster and more thoroughly. In developing this explanation, we use the concepts of sub-diffusive, normally-diffusive, and super-diffusive random walks (RWs) originally developed in the field of statistical physics.

The Evaluation of Triphenyl Phosphate as a Flame Retardant Additive to Improve the Safety of Lithium-Ion Battery Electrolytes

NASA Technical Reports Server (NTRS)

Smart, M. C.; Krause, F. C.; Hwang, C.; West, W. C.; Soler, J.; Prakash, G. K. S.; Ratnakumar, B. V.

2011-01-01

With the intent of improving the safety characteristics of lithium ion cells, electrolytes containing flame retardant additives have been investigated. A number of triphenyl phosphate-containing electrolytes were evaluated in both coin cells and experimental three electrode lithium-ion cells (containing reference electrodes). A number of chemistries were investigated, including MCMB carbon/LiNi(0.8)Co(0.2)O2 (NCO), graphite/LiNi(0.8)Co(0.15)Al(0.05)O2 (NCA), Li/Li(Li(0.17)Ni(0.25)Mn(0.58))O2, Li/LiNiMnCoO2 (NMC) and graphite/LiNiMnCoO2 (NMC), to study the effect that different electrolyte compositions have upon performance. A wide range of TPP-containing electrolytes were demonstrated to have good compatibility with the C/NCO, C/NCA, and Li/NMC systems, however, poor performance was initially observed with the high voltage C/NMC system. This necessitated the development of improved electrolytes with stabilizing additives, leading to formulations containing lithium bis(oxalato)borate (LiBOB) that displayed substantially improved performance.

Performance characteristics of ring-cusp thrusters with xenon propellant

NASA Technical Reports Server (NTRS)

Patterson, M. J.

1986-01-01

The performance characteristics and operating envelope of several 30-cm ring-cusp ion thrusters with xenon propellant were investigated. Results indicate a strong performance dependence on the discharge chamber boundary magnetic fields and resultant distribution of electron currents. Significant improvements in discharge performance over J-series divergent-field thrusters were achieved for large throttling ranges, which translate into reduced cathode emission currents and reduced power dissipation which should be of significant benefit for operation at thruster power levels in excess of 10 kW. Mass spectrometry of the ion beam was documented for both the ring-cusp and J-series thrusters with xenon propellant for determination of overall thruster efficiency, and lifetime. Based on the lower centerline values of doubly charged ions in the ion beam and the lower operating discharge voltage, the screen grid erosion rate of the ring-cusp thruster is expected to be lower than the divergent-field J-series thruster by a factor of 2.

Performance characteristics of ring-cusp thrusters with xenon propellant

NASA Technical Reports Server (NTRS)

Patterson, M. J.

1986-01-01

The performance characteristics and operating envelope of several 30-cm ring-cusp ion thrusters with xenon propellant were investigated. Results indicate a strong performance dependence on the discharge chamber boundary magnetic fields and resultant distribution of electron currents. Significant improvements in discharge performance over J-series divergent-field thrusters were achieved for large throttling ranges, which translate into reduced cathode emission currents and reduced power dissipation which should be of significant benefit for operation at thruster power levels in excess of 10 kW. Mass spectrometer of the ion beam was documented for both the ring-cusp and J-series thrusters with xenon propellant for determination of overall thruster efficiency, and lifetime. Based on the lower centerline values of doubly charged ions in the ion beam and the lower operating discharge voltage, the screen grid erosion rate of the ring-cusp thruster is expected to be lower than the divergent-field J-series thruster by a factor of 2.

Recent advances and developments in composite dental restorative materials.

PubMed

Cramer, N B; Stansbury, J W; Bowman, C N

2011-04-01

Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance.

Development of energy-saving devices for a full slow-speed ship through improving propulsion performance

NASA Astrophysics Data System (ADS)

Kim, Jung-Hun; Choi, Jung-Eun; Choi, Bong-Jun; Chung, Seok-Ho; Seo, Heung-Won

2015-06-01

Energy-saving devices for 317K VLCC have been developed from a propulsion standpoint. Two ESD candidates were designed via computational tools. The first device WAFon composes of flow-control fins adapted for the ship wake to reduce the loss of rotational energy. The other is WAFon-D, which is a WAFon with a duct to obtain additional thrust and to distribute the inflow velocity on the propeller plane uniform. After selecting the candidates from the computed results, the speed performances were validated with model-tests. The hydrodynamic characteristics of the ESDs may be found in improved hull and propulsive efficiencies through increased wake fraction.

Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.

PubMed

Chung, Yun Won; Kwon, Jae Kyun; Park, Suwon

2014-01-01

One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds.

Recent Advances and Developments in Composite Dental Restorative Materials

PubMed Central

Cramer, N.B.; Stansbury, J.W.; Bowman, C.N.

2011-01-01

Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance. PMID:20924063

USB noise reduction by nozzle and flap modifications

NASA Technical Reports Server (NTRS)

Hayden, R. E.

1976-01-01

The development of concepts for reducing upper surface blown flap noise at the source through flap modifications and special nozzles is reviewed. In particular, recent results obtained on the aerodynamic and acoustic performance of flaps with porous surfaces near the trailing edge and multi-slotted nozzles are reviewed. Considerable reduction (6-10 db) of the characteristic low frequency peak is shown. The aerodynamic performance is compared with conventional systems, and prospects for future improvements are discussed.

Split-Stirling-cycle displacer linear-electric drive

NASA Technical Reports Server (NTRS)

Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

1983-01-01

The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

Improvement of kink characteristic of proton-implanted VCSEL with ITO overcoating

NASA Astrophysics Data System (ADS)

Lai, Fang-I.; Chang, Ya-Hsien; Laih, Li-Hong; Kuo, Hao-chung; Wang, S. C.

2004-06-01

Proton implanted VCSEL has been demonstrated with good reliability and decent modulation speed up to 1.25 Gb/s. However, kinks in current vs light output (L-I) has been always an issue in the gain-guided proton implant VCSEL. The kink related jitter and noise performance made it difficult to meet 2.5 Gb/s (OC-48) requirement. The kinks in L-I curve can be attributed to non-uniform carrier distribution induced non-uniform gain distribution within emission area. In this paper, the effects of a Ti/ITO transparent over-coating on the proton-implanted AlGaAs/GaAs VCSELs (15um diameter aperture) are investigated. The kinks distribution in L-I characteristics from a 2 inch wafer is greatly improved compared to conventional process. These VCSELs exhibit nearly kink-free L-I output performance with threshold currents ~3 mA, and the slope efficiencies ~ 0.25 W/A. The near-field emission patterns suggest the Ti/ITO over-coating facilitates the current spreading and uniform carrier distribution of the top VCSEL contact thus enhancing the laser performance. Finally, we performed high speed modulation measurement. The eye diagram of proton-implanted VCSELs with Ti/ITO transparent over-coating operating at 2.125 Gb/s with 10mA bias and 9dB extinction ratio shows very clean eye with jitter less than 35 ps.

Seed vigour and crop establishment: extending performance beyond adaptation.

PubMed

Finch-Savage, W E; Bassel, G W

2016-02-01

Seeds are central to crop production, human nutrition, and food security. A key component of the performance of crop seeds is the complex trait of seed vigour. Crop yield and resource use efficiency depend on successful plant establishment in the field, and it is the vigour of seeds that defines their ability to germinate and establish seedlings rapidly, uniformly, and robustly across diverse environmental conditions. Improving vigour to enhance the critical and yield-defining stage of crop establishment remains a primary objective of the agricultural industry and the seed/breeding companies that support it. Our knowledge of the regulation of seed germination has developed greatly in recent times, yet understanding of the basis of variation in vigour and therefore seed performance during the establishment of crops remains limited. Here we consider seed vigour at an ecophysiological, molecular, and biomechanical level. We discuss how some seed characteristics that serve as adaptive responses to the natural environment are not suitable for agriculture. Past domestication has provided incremental improvements, but further actively directed change is required to produce seeds with the characteristics required both now and in the future. We discuss ways in which basic plant science could be applied to enhance seed performance in crop production. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Examining the Role of Group Experimental Research in Establishing Evidenced-Based Practices

ERIC Educational Resources Information Center

Cook, Lysandra; Cook, Bryan G.; Landrum, Timothy J.; Tankersley, Melody

2008-01-01

Using evidence-based practices, or those instructional techniques shown by research to improve student outcomes meaningfully, increases the performance of students with disabilities and should therefore be a priority for special educators. But how does a practice come to be considered evidence based? The unique characteristics of group…

"The Types of Kids We Get Are Different"--The Distinguishing Characteristics of School Choosers in Detroit, Michigan

ERIC Educational Resources Information Center

Hamlin, Daniel

2018-01-01

Providing improved educational options for low-income African American families has been one of the primary objectives of the charter school movement. However, among demographically similar families, school choosers may possess subtle advantages compared to nonchoosers, leading to biased estimates of charter school performance in nonexperimental…

The slab geometry laser. I - Theory

NASA Technical Reports Server (NTRS)

Eggleston, J. M.; Kane, T. J.; Kuhn, K.; Byer, R. L.; Unternahrer, J.

1984-01-01

Slab geometry solid-state lasers offer significant performance improvements over conventional rod-geometry lasers. A detailed theoretical description of the thermal, stress, and beam-propagation characteristics of a slab laser is presented. The analysis includes consideration of the effects of the zig-zag optical path, which eliminates thermal and stress focusing and reduces residual birefringence.

Laboratory to commercial scale - Correlation in the physical properties of biofiber-polymer composites.

USDA-ARS?s Scientific Manuscript database

Bio-fiber polymer composites have been the focus of automotive and building products industries for the last several years. Significant research has been done to improve the processing and performance characteristics of the bio-fiber composite. Most of the initial research is conducted on a small sc...

Data-Acquisition System With Remotely Adjustable Amplifiers

NASA Technical Reports Server (NTRS)

Nurge, Mark A.; Larson, William E.; Hallberg, Carl G.; Thayer, Steven W.; Ake, Jeffrey C.; Gleman, Stuart M.; Thompson, David L.; Medelius, Pedro J.; Crawford, Wayne A.; Vangilder, Richard M.;

Effects of dehydration methods on characteristics of fibrous networks from un-tanned hides

USDA-ARS?s Scientific Manuscript database

To improve prospective markets and to secure a viable future for the hides and leather industries, it is important to develop new uses and novel biobased products from hides. We hypothesize collagen fiber networks derived from un-tanned hides can be utilized to prepare high performance green compos...

Effects of dehydration methods on the characteristics of fibrous networks from un-tanned hides

USDA-ARS?s Scientific Manuscript database

To improve prospective markets and to secure a viable future for the hides and leather industries, it is important to develop new uses and novel biobased products from hides. We hypothesize collagen fiber networks derived from un-tanned hides can be utilized to prepare high performance green compos...

The Effect of Physical Training on Static Balance in Young People with Intellectual Disability

ERIC Educational Resources Information Center

Jankowicz-Szymanska, A.; Mikolajczyk, E.; Wojtanowski, W.

2012-01-01

Intellectual disability affects all spheres of people's lives who suffer from it. It lowers the level of intellectual functioning, often stigmatizes, characteristically changing features, and decreases motor performance. Unfortunately, modern medicine cannot cure intellectual disability; however, there is a chance to improve the quality of life of…

Using Goal Analysis to Drive Improvements in Performance and Outcomes

ERIC Educational Resources Information Center

Lawlor, David; Spitz, Romy; York, Michaela; Harvey, Brenda

2013-01-01

Economic pressures for public health and human services systems to control budgets are increasing the need for demonstrating value of support services provided to persons with intellectual disabilities. In this article, we build from earlier work that presented a method for assessing goal attainment to expand the study of goal characteristics as a…

Improving L2 Reading Comprehension through Emotionalized Dynamic Assessment Procedures

ERIC Educational Resources Information Center

Abdolrezapour, Parisa

2017-01-01

The paper reports a study on an emotionally-loaded dynamic assessment procedure used with Iranian EFL learners. It focuses on the effect of using emotional intelligence characteristics (based on Goleman's framework) as a tool for motivating learners while performing reading tasks. The study with 50 intermediate learners aged 12-15 used three…

Effects of Game-Based Learning in an Opensim-Supported Virtual Environment on Mathematical Performance

ERIC Educational Resources Information Center

Kim, Heesung; Ke, Fengfeng

2017-01-01

This experimental study was intended to examine whether the integration of game characteristics in the OpenSimulator-supported virtual reality (VR) learning environment can improve mathematical achievement for elementary school students. In this pre- and posttest experimental comparison study, data were collected from 132 fourth graders through an…

Analysis of the Characteristics of a Rotary Stepper Micromotor

NASA Astrophysics Data System (ADS)

Sone, Junji; Mizuma, Toshinari; Masunaga, Masakazu; Mochizuki, Shunsuke; Sarajic, Edin; Yamahata, Christophe; Fujita, Hiroyuki

A 3-phase electrostatic stepper micromotor was developed. To improve its performance for actual use, we have conducted numerical simulation to optimize the design. An improved simulation method is needed for calculation of various cases. To conduct circuit simulation of this micromotor, its structure is simplified, and a function for computing the force excited by the electrostatic field is added to the circuit simulator. We achieved a reasonably accurate simulation. We also considered an optimal drive waveform to achieve low-voltage operation.

Modeling and Analysis of Composite Wing Sections for Improved Aeroelastic and Vibration Characteristics Using Smart Materials

NASA Technical Reports Server (NTRS)

Chattopadhyay, Aditi

1996-01-01

The objective of this research is to develop analysis procedures to investigate the coupling of composite and smart materials to improve aeroelastic and vibratory response of aerospace structures. The structural modeling must account for arbitrarily thick geometries, embedded and surface bonded sensors and actuators and imperfections, such as delamination. Changes in the dynamic response due to the presence of smart materials and delaminations is investigated. Experiments are to be performed to validate the proposed mathematical model.

Shuttle orbiter Ku-band radar/communications system design evaluation: High gain antenna/widebeam horn

NASA Technical Reports Server (NTRS)

Iwasaki, R.; Dodds, J. G.; Broad, P.

1979-01-01

The physical characteristics of the high gain antenna reflector and feed elements are described. Deficiencies in the sum feed are discussed, and lack of atmospheric venting is posed as a potential problem area. The measured RF performance of the high gain antenna is examined and the high sidelobe levels measured are related to the physical characteristics of the antenna. An examination of the attributes of the feed which might be influenced by temperature extremes shows that the antenna should be insensitive to temperature variations. Because the feed support bipod structure is considered a significant contributor to the high sidelobe levels measured in the azimuth plane, pod relocation, material changes, and shaping are suggested as improvements. Alternate feed designs are presented to further improve system performance. The widebeam horn and potential temperature effects due to the polarizer are discussed as well as in the effects of linear polarization on TDRS acquisition, and the effects of circular polarization on radar sidelobe avoidance. The radar detection probability is analyzed as a function of scan overlap and target range.

Physical and chemical characteristics of products from the torrefaction of yellow poplar (Liriodendron tulipifera).

PubMed

Kim, Young-Hun; Lee, Soo-Min; Lee, Hyoung-Woo; Lee, Jae-Won

2012-07-01

We investigated the characteristics of torrefied yellow poplar (Liriodendron tulipifera) depending on reaction time (30 min) and temperature (240-280 °C). The thermogravimetric, grindability and calorific value of torrefied biomass were analyzed. As the torrefaction temperature increased, the carbon content of torrefied biomass increased from 49.50% to 54.42%, while the hydrogen and oxygen contents decreased from 6.09% to 5.65% and 28.71% to 26.61%, respectively. The highest calorific value was 1233 kJ/kg when torrefaction was performed at 280 °C for 30 min. An overall increase in energy density and decrease in mass and energy yield was observed with the increase in torrefaction temperature. The analysis of thermal decomposition demonstrated that the hemicelluloses contained in torrefied biomass decreased with increasing torrefaction temperature, whereas cellulose and lignin were only slightly affected. The grindability of torrefied biomass was significantly improved when torrefaction was performed at high temperature. Torrefaction of yellow poplar improved the chemical and physical fuel properties of the biomass. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Time Course of Improvements in Power Characteristics in Elite Development Netball Players Entering a Full-Time Training Program.

PubMed

McKeown, Ian; Chapman, Dale W; Taylor, Kristie Lee; Ball, Nick B

2016-05-01

We describe the time course of adaptation to structured resistance training on entering a full-time high-performance sport program. Twelve international caliber female netballers (aged 19.9 ± 0.4 years) were monitored for 18 weeks with countermovement (CMJ: performed with body weight and 15 kg) and drop jumps (0.35-m box at body weight) at the start of each training week. Performance did not improve linearly or concurrently with loaded CMJ power improving 11% by Week 5 (effect size [ES] 0.93 ± 0.72) in contrast, substantial positive changes were observed for unloaded CMJ power (12%; ES 0.78 ± 0.39), and CMJ velocity (unloaded: 7.1%; ES 0.66 ± 0.34; loaded: 7.5%; ES 0.90 ± 0.41) by week 7. Over the investigation duration, large improvements were observed in unloaded CMJ power (24%; ES 1.45 ± 1.11) and velocity (12%; ES 1.13 ± 0.76). Loaded CMJ power also showed a large improvement (19%; ES 1.49 ± 0.97) but only moderate changes were observed for loaded CMJ velocity (8.4%; ES 1.01 ± 0.67). Jump height changes in either unloaded or loaded CMJ were unclear over the 18-week period. Drop jump performance improved throughout the investigation period with moderate positive changes in reactive strength index observed (35%; ES 0.97 ± 0.69). The adaptation response to a structured resistance training program does not occur linearly in young female athletes. Caution should be taken if assessing jump height only, as this will provide a biased observation to a training response. Frequently assessing CMJ performance can aid program design coaching decisions to ensure improvements are seen past the initial neuromuscular learning phase in performance training.

Li-Ion Electrolytes with Improved Safety and Tolerance to High-Voltage Systems

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Bugga, Ratnakumar V.; Prakash, Surya; Krause, Frederick C.

2013-01-01

Given that lithium-ion (Li-ion) technology is the most viable rechargeable energy storage device for near-term applications, effort has been devoted to improving the safety characteristics of this system. Therefore, extensive effort has been devoted to developing nonflammable electrolytes to reduce the flammability of the cells/battery. A number of promising electrolytes have been developed incorporating flame-retardant additives, and have been shown to have good performance in a number of systems. However, these electrolyte formulations did not perform well when utilizing carbonaceous anodes with the high-voltage materials. Thus, further development was required to improve the compatibility. A number of Li-ion battery electrolyte formulations containing a flame-retardant additive [i.e., triphenyl phosphate (TPP)] were developed and demonstrated in high-voltage systems. These electrolytes include: (1) formulations that incorporate varying concentrations of the flame-retardant additive (from 5 to 15%), (2) the use of mono-fluoroethylene carbonate (FEC) as a co-solvent, and (3) the use of LiBOB as an electrolyte additive intended to improve the compatibility with high-voltage systems. Thus, improved safety has been provided without loss of performance in the high-voltage, high-energy system.

Novel Biocompatible Thermoresponsive Poly(N-vinyl Caprolactam)/Clay Nanocomposite Hydrogels with Macroporous Structure and Improved Mechanical Characteristics.

PubMed

Shi, Kun; Liu, Zhuang; Yang, Chao; Li, Xiao-Ying; Sun, Yi-Min; Deng, Yi; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

2017-07-05

Poly(N-vinyl caprolactam) (PVCL) hydrogels usually suffer from the imporous structure and poor mechanical characteristics as well as the toxicity of cross-linkers, although PVCL itself is biocompatible. In this paper, novel biocompatible thermoresponsive poly(N-vinyl caprolactam)/clay nanocomposite (PVCL-Clay) hydrogels with macroporous structure and improved mechanical characteristics are developed for the first time. The macroporosity in the hydrogel is introduced by using Pickering emulsions as templates, which contain N-vinyl caprolactam (VCL) monomer as dispersed phase and clay sheets as stabilizers at the interface. After polymerization, macropores are formed inside the hydrogels with the residual unreacted VCL droplets as templates. The three-dimensional PVCL polymer networks are cross-linked by the clay nanosheets. Due to the nanocomposite structure, the hydrogel exhibits better mechanical characteristics in comparison to the conventional PVCL hydrogels cross-linked by N,N'-methylene diacrylamide (BIS). The prepared PVCL-Clay hydrogel possesses remarkable temperature-responsive characteristics with a volume phase transition temperature (VPTT) around 35 °C, and provides a feasible platform for cell culture. With macroporous structure and good mechanical characteristics as well as flexible assembly performance, the proposed biocompatible thermoresponsive PVCL-Clay nanocomposite hydrogels are ideal material candidates for biomedical, analytical, and other applications such as entrapment of enzymes, cell culture, tissue engineering, and affinity and displacement chromatography.

Enhanced two dimensional electron gas transport characteristics in Al2O3/AlInN/GaN metal-oxide-semiconductor high-electron-mobility transistors on Si substrate

NASA Astrophysics Data System (ADS)

Freedsman, J. J.; Watanabe, A.; Urayama, Y.; Egawa, T.

2015-09-01

The authors report on Al2O3/Al0.85In0.15N/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistor (MOS-HEMT) on Si fabricated by using atomic layer deposited Al2O3 as gate insulator and passivation layer. The MOS-HEMT with the gate length of 2 μm exhibits excellent direct-current (dc) characteristics with a drain current maximum of 1270 mA/mm at a gate bias of 3 V and an off-state breakdown voltage of 180 V for a gate-drain spacing of 4 μm. Also, the 1 μm-gate MOS-HEMT shows good radio-frequency (rf) response such as current gain and maximum oscillation cut-off frequencies of 10 and 34 GHz, respectively. The capacitance-voltage characteristics at 1 MHz revealed significant increase in two-dimensional electron gas (2DEG) density for the MOS-HEMT compared to conventional Schottky barrier HEMTs. Analyses using drain-source conductivity measurements showed improvements in 2DEG transport characteristics for the MOS-HEMT. The enhancements in dc and rf performances of the Al2O3/Al0.85In0.15N/GaN MOS-HEMT are attributed to the improvements in 2DEG characteristics.

Experimental and Numerical Analysis of Performance Discontinuity of a Pump-Turbine under Pumping Mode

NASA Astrophysics Data System (ADS)

Zhang, X.; Burgstaller, R.; Lai, X.; Gehrer, A.; Kefalas, A.; Pang, Y.

2016-11-01

The performance discontinuity of a pump-turbine under pumping mode is harmful to stable operation of units in hydropower station. In this paper, the performance discontinuity phenomenon of the pump-turbine was studied by means of experiment and numerical simulation. In the experiment, characteristics of the pump-turbine with different diffuser vane openings were tested in order to investigate the effect of pumping casing to the performance discontinuity. While other effects such as flow separation and rotating stall are known to have an effect on the discontinuity, the present studied test cases show that prerotation is the dominating effect for the instability, positions of the positive slope of characteristics are almost the same in different diffuser vane opening conditions. The impeller has principal effect to the performance discontinuity. In the numerical simulation, CFD analysis of tested pump-turbine has been done with k-ω and SST turbulence model. It is found that the position of performance curve discontinuity corresponds to flow recirculation at impeller inlet. Flow recirculation at impeller inlet is the cause of the discontinuity of characteristics curve. It is also found that the operating condition of occurrence of flow recirculation at impeller inlet is misestimated with k-ω and SST turbulence model. Furthermore, the original SST model has been modified. We predict the occurrence position of flow recirculation at impeller inlet correctly with the modified SST turbulence model, and it also can improve the prediction accuracy of the pump- turbine performance at the same time.

Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

NASA Technical Reports Server (NTRS)

Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

2012-01-01

Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

Human perception testing methodology for evaluating EO/IR imaging systems

NASA Astrophysics Data System (ADS)

Graybeal, John J.; Monfort, Samuel S.; Du Bosq, Todd W.; Familoni, Babajide O.

2018-04-01

The U.S. Army's RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) Perception Lab is tasked with supporting the development of sensor systems for the U.S. Army by evaluating human performance of emerging technologies. Typical research questions involve detection, recognition and identification as a function of range, blur, noise, spectral band, image processing techniques, image characteristics, and human factors. NVESD's Perception Lab provides an essential bridge between the physics of the imaging systems and the performance of the human operator. In addition to quantifying sensor performance, perception test results can also be used to generate models of human performance and to drive future sensor requirements. The Perception Lab seeks to develop and employ scientifically valid and efficient perception testing procedures within the practical constraints of Army research, including rapid development timelines for critical technologies, unique guidelines for ethical testing of Army personnel, and limited resources. The purpose of this paper is to describe NVESD Perception Lab capabilities, recent methodological improvements designed to align our methodology more closely with scientific best practice, and to discuss goals for future improvements and expanded capabilities. Specifically, we discuss modifying our methodology to improve training, to account for human fatigue, to improve assessments of human performance, and to increase experimental design consultation provided by research psychologists. Ultimately, this paper outlines a template for assessing human perception and overall system performance related to EO/IR imaging systems.

Amine-Modulated/Engineered Interfaces of NiMo Electrocatalysts for Improved Hydrogen Evolution Reaction in Alkaline Solutions.

PubMed

Gao, Wei; Gou, Wangyan; Zhou, Xuemei; Ho, Johnny C; Ma, Yuanyuan; Qu, Yongquan

2018-01-17

The interface between electrolytes and electrocatalysts would largely determine their corresponding activity and stability. Herein, modulating the surface characteristics of NiMo nanoparticles by various adsorbed amines gives the tunability on their interfacial properties and subsequently improves their catalytic performance for hydrogen evolution reaction (HER) in alkaline solutions. Diamines can significantly improve their HER activity by decreasing the charge-transfer resistance and modulating the electronic structures of interfacial active sites. Importantly, among various amines, ethylenediamine facilitates the HER activity of NiMo with a remarkable decrease of 268 mV in the overpotential to reach 10 mA cm -2 as compared with that of the unmodified NiMo in 1.0 M KOH. This method provides a novel strategy of regulating the interfacial properties to strengthen the catalytic performance of electrocatalysts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Kun; Marcus, Kyle; Yang, Zhenzhong

In this work, a freestanding NiFe oxyfluoride (NiFeOF) holey film was prepared by electrochemical deposition and anodic treatments. With the combination of good electrical conductivity and holey structure, the NiFeOF holey film offers superior electrochemical performance, due to the following reasons: (i) The residual metal alloy framework can be used as the current collector to improve electrode conductivity. Moreover, the as-prepared freestanding NiFeOF holey film can be used as a supercapacitor electrode without reliance on binders and other additives. The residual metal alloy framework and binder-free electrode effectively reduces electrode resistance, thus improving electron transport. (ii) The highly interconnected holeymore » structure and hierarchical pore distribution provides a high specific surface area to improve electron transport, enhancing rapid ion transport and mitigating diffusion limitations throughout the holey film. (iii) The excellent mechanical characteristics facilitate flexibility and cyclability related performance. Additionally, the NiFeOF holey film presents exceptional electrochemical performance, showing that it is a promising alternative for small/micro-size electronic devices.« less

Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoessel, Chris

2013-11-13

This project developed a new high-performance R-10/high SHGC window design, reviewed market positioning and evaluated manufacturing solutions required for broad market adoption. The project objectives were accomplished by: identifying viable technical solutions based on modeling of modern and potential coating stacks and IGU designs; development of new coating material sets for HM thin film stacks, as well as improved HM IGU designs to accept multiple layers of HM films; matching promising new coating designs with new HM IGU designs to demonstrate performance gains; and, in cooperation with a window manufacturer, assess the potential for high-volume manufacturing and cost efficiency ofmore » a HM-based R-10 window with improved solar heat gain characteristics. A broad view of available materials and design options was applied to achieve the desired improvements. Gated engineering methodologies were employed to guide the development process from concept generation to a window demonstration. The project determined that a slightly de-rated window performance allows formulation of a path to achieve the desired cost reductions to support end consumer adoption.« less

Improved performance of nanoscale junctionless tunnel field-effect transistor based on gate engineering approach

NASA Astrophysics Data System (ADS)

Molaei Imen Abadi, Rouzbeh; Sedigh Ziabari, Seyed Ali

2016-11-01

In this paper, a first qualitative study on the performance characteristics of dual-work function gate junctionless TFET (DWG-JLTFET) on the basis of energy band profile modulation is investigated. A dual-work function gate technique is used in a JLTFET in order to create a downward band bending on the source side similar to PNPN structure. Compared with the single-work function gate junctionless TFET (SWG-JLTFET), the numerical simulation results demonstrated that the DWG-JLTFET simultaneously optimizes the ON-state current, the OFF-state leakage current, and the threshold voltage and also improves average subthreshold slope. It is illustrated that if appropriate work functions are selected for the gate materials on the source side and the drain side, the JLTFET exhibits a considerably improved performance. Furthermore, the optimization design of the tunnel gate length ( L Tun) for the proposed DWG-JLTFET is studied. All the simulations are done in Silvaco TCAD for a channel length of 20 nm using the nonlocal band-to-band tunneling (BTBT) model.

Modulated CH3NH3PbI3−xBrx film for efficient perovskite solar cells exceeding 18%

PubMed Central

Tu, Yongguang; Wu, Jihuai; Lan, Zhang; He, Xin; Dong, Jia; Jia, Jinbiao; Guo, Panfeng; Lin, Jianming; Huang, Miaoliang; Huang, Yunfang

2017-01-01

The organic-inorganic lead halide perovskite layer is a crucial factor for the high performance perovskite solar cell (PSC). We introduce CH3NH3Br in the precursor solution to prepare CH3NH3PbI3−xBrx hybrid perovskite, and an uniform perovskite layer with improved crystallinity and apparent grain contour is obtained, resulting in the significant improvement of photovoltaic performance of PSCs. The effects of CH3NH3Br on the perovskite morphology, crystallinity, absorption property, charge carrier dynamics and device characteristics are discussed, and the improvement of open circuit voltage of the device depended on Br doping is confirmed. Based on above, the device based on CH3NH3PbI2.86Br0.14 exhibits a champion power conversion efficiency (PCE) of 18.02%. This study represents an efficient method for high-performance perovskite solar cell by modulating CH3NH3PbI3−xBrx film. PMID:28303938

Redesigning a clinical mentoring program for improved outcomes in the clinical training of clerks

PubMed Central

Lin, Chia-Der; Lin, Blossom Yen-Ju; Lin, Cheng-Chieh; Lee, Cheng-Chun

2015-01-01

Introduction Mentorship has been noted as critical to medical students adapting to clinical training in the medical workplace. A lack of infrastructure in a mentoring program might deter relationship building between mentors and mentees. This study assessed the effect of a redesigned clinical mentoring program from the perspective of clerks. The objective was to assess the benefits of the redesigned program and identify potential improvements. Methods A redesigned clinical mentoring program was launched in a medical center according to previous theoretical and practical studies on clinical training workplaces, including the elements of mentor qualifications, positive and active enhancers for mentor–mentee relationship building, the timing of mentoring performance evaluation, and financial and professional incentives. A four-wave web survey was conducted, comprising one evaluation of the former mentoring program and three evaluations of the redesigned clinical mentoring program. Sixty-four fifth-year medical students in clerkships who responded to the first wave and to at least two of the three following waves were included in the study. A structured and validated questionnaire encompassing 15 items on mentor performance and the personal characteristics of the clerks was used. Mixed linear models were developed for repeated measurements and to adjust for personal characteristics. Results The results revealed that the redesigned mentoring program improved the mentors’ performance over time for most evaluated items regarding professional development and personal support provided to the mentees. Conclusions Our findings serve as an improved framework for the role of the institution and demonstrate how institutional policies, programs, and structures can shape a clinical mentoring program. We recommend the adoption of mentorship schemes for other cohorts of medical students and for different learning and training stages involved in becoming a physician. PMID:26384479

Multi-metric calibration of hydrological model to capture overall flow regimes

NASA Astrophysics Data System (ADS)

Zhang, Yongyong; Shao, Quanxi; Zhang, Shifeng; Zhai, Xiaoyan; She, Dunxian

2016-08-01

Flow regimes (e.g., magnitude, frequency, variation, duration, timing and rating of change) play a critical role in water supply and flood control, environmental processes, as well as biodiversity and life history patterns in the aquatic ecosystem. The traditional flow magnitude-oriented calibration of hydrological model was usually inadequate to well capture all the characteristics of observed flow regimes. In this study, we simulated multiple flow regime metrics simultaneously by coupling a distributed hydrological model with an equally weighted multi-objective optimization algorithm. Two headwater watersheds in the arid Hexi Corridor were selected for the case study. Sixteen metrics were selected as optimization objectives, which could represent the major characteristics of flow regimes. Model performance was compared with that of the single objective calibration. Results showed that most metrics were better simulated by the multi-objective approach than those of the single objective calibration, especially the low and high flow magnitudes, frequency and variation, duration, maximum flow timing and rating. However, the model performance of middle flow magnitude was not significantly improved because this metric was usually well captured by single objective calibration. The timing of minimum flow was poorly predicted by both the multi-metric and single calibrations due to the uncertainties in model structure and input data. The sensitive parameter values of the hydrological model changed remarkably and the simulated hydrological processes by the multi-metric calibration became more reliable, because more flow characteristics were considered. The study is expected to provide more detailed flow information by hydrological simulation for the integrated water resources management, and to improve the simulation performances of overall flow regimes.

Methods for assessing fracture risk prediction models: experience with FRAX in a large integrated health care delivery system.

PubMed

Pressman, Alice R; Lo, Joan C; Chandra, Malini; Ettinger, Bruce

2011-01-01

Area under the receiver operating characteristics (AUROC) curve is often used to evaluate risk models. However, reclassification tests provide an alternative assessment of model performance. We performed both evaluations on results from FRAX (World Health Organization Collaborating Centre for Metabolic Bone Diseases, University of Sheffield, UK), a fracture risk tool, using Kaiser Permanente Northern California women older than 50yr with bone mineral density (BMD) measured during 1997-2003. We compared FRAX performance with and without BMD in the model. Among 94,489 women with mean follow-up of 6.6yr, 1579 (1.7%) sustained a hip fracture. Overall, AUROCs were 0.83 and 0.84 for FRAX without and with BMD, suggesting that BMD did not contribute to model performance. AUROC decreased with increasing age, and BMD contributed significantly to higher AUROC among those aged 70yr and older. Using an 81% sensitivity threshold (optimum level from receiver operating characteristic curve, corresponding to 1.2% cutoff), 35% of those categorized above were reassigned below when BMD was added. In contrast, only 10% of those categorized below were reassigned to the higher risk category when BMD was added. The net reclassification improvement was 5.5% (p<0.01). Two versions of this risk tool have similar AUROCs, but alternative assessments indicate that addition of BMD improves performance. Multiple methods should be used to evaluate risk tool performance with less reliance on AUROC alone. Copyright © 2011 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Improving performance of natural language processing part-of-speech tagging on clinical narratives through domain adaptation.

PubMed

Ferraro, Jeffrey P; Daumé, Hal; Duvall, Scott L; Chapman, Wendy W; Harkema, Henk; Haug, Peter J

2013-01-01

Natural language processing (NLP) tasks are commonly decomposed into subtasks, chained together to form processing pipelines. The residual error produced in these subtasks propagates, adversely affecting the end objectives. Limited availability of annotated clinical data remains a barrier to reaching state-of-the-art operating characteristics using statistically based NLP tools in the clinical domain. Here we explore the unique linguistic constructions of clinical texts and demonstrate the loss in operating characteristics when out-of-the-box part-of-speech (POS) tagging tools are applied to the clinical domain. We test a domain adaptation approach integrating a novel lexical-generation probability rule used in a transformation-based learner to boost POS performance on clinical narratives. Two target corpora from independent healthcare institutions were constructed from high frequency clinical narratives. Four leading POS taggers with their out-of-the-box models trained from general English and biomedical abstracts were evaluated against these clinical corpora. A high performing domain adaptation method, Easy Adapt, was compared to our newly proposed method ClinAdapt. The evaluated POS taggers drop in accuracy by 8.5-15% when tested on clinical narratives. The highest performing tagger reports an accuracy of 88.6%. Domain adaptation with Easy Adapt reports accuracies of 88.3-91.0% on clinical texts. ClinAdapt reports 93.2-93.9%. ClinAdapt successfully boosts POS tagging performance through domain adaptation requiring a modest amount of annotated clinical data. Improving the performance of critical NLP subtasks is expected to reduce pipeline error propagation leading to better overall results on complex processing tasks.

Westerly wind bursts simulated in CAM4 and CCSM4

NASA Astrophysics Data System (ADS)

Lian, Tao; Tang, Youmin; Zhou, Lei; Islam, Siraj Ul; Zhang, Chan; Li, Xiaojing; Ling, Zheng

2018-02-01

The equatorial westerly wind bursts (WWBs) play an important role in modulating and predicting the El Niño-Southern Oscillation (ENSO). In this study, the ability of the Community Atmospheric Model version 4 (CAM4) and the Community Climate System Model version 4 (CCSM4) in simulating WWBs is systematically evaluated. Many characteristics of WWBs, including their longitude distributions, durations, zonal extensions, variabilities at seasonal, intraseasonal, and interannual timescales, as well as their relations with the Madden-Julian Oscillation (MJO) and ENSO, are discussed. Generally speaking, these characteristics of WWBs can be successfully reproduced by CAM4, owning to the improvement of the deep convection in the model. In CCSM4, significant bias such as the lack of the equatorial Pacific WWBs in boreal spring season and the weak modulation by a strong MJO are found. Our findings confirm the fact that the WWBs are greatly modulated by the surface temperature. It's also suggested that improving the air-sea coupling in CCSM4 may improve model performance in simulating WWBs, and may further improve the predictability of ENSO in the coupled model.

Performance of new alternative providers of primary care services in England: an observational study

PubMed Central

Greaves, Felix; Laverty, Anthony A; Pape, Utz; Ratneswaren, Anenta; Majeed, Azeem

2015-01-01

Summary Objectives Health system reforms in England are opening broad areas of clinical practice to new providers of care. As part of these reforms, new entrants – including private companies – have been allowed into the primary care market under ‘alternative provider of medical services’ contracting mechanisms since 2004. The characteristics and performance of general practices working under new alternative provider contracts are not well described. We sought to compare the quality of care provided by new entrant providers to that provided by the traditional model of general practice. Design Open cohort study of English general practices. We used linear regression in cross-sectional and time series analyses, adjusting for practice and population characteristics, to compare quality in practices using alternative provider contracts to traditional practices. We created regression models using practice fixed effects to estimate the impact of practices changing to the new contract type. Setting The English National Health Service. Participants All general practices open from 2008/2009 to 2012/2013. Main outcome measures Seventeen established quality indicators – covering clinical effectiveness, efficiency, access and patient experience. Results In total, 4.1% (347 of 8300) of general practices in England were run by alternative contract providers. These practices tended to be smaller, and serve younger, more diverse and more deprived populations than traditional providers. Practices run by alternative providers performed worse than traditional providers on 15 of 17 indicators after adjusting for practice and population characteristics (p < 0.01 for all). Switching to a new alternative provider contract did not result in improved performance. Conclusions The introduction of new alternative providers to deliver primary care services in England has not led to improvements in quality and may have resulted in worse care. Regulators should ensure that new entrants to clinical provider markets are performing to adequate standards and at least as well as traditional providers. PMID:25908312

Performance of new alternative providers of primary care services in England: an observational study.

PubMed

Greaves, Felix; Laverty, Anthony A; Pape, Utz; Ratneswaren, Anenta; Majeed, Azeem; Millett, Christopher

2015-05-01

Health system reforms in England are opening broad areas of clinical practice to new providers of care. As part of these reforms, new entrants--including private companies--have been allowed into the primary care market under 'alternative provider of medical services' contracting mechanisms since 2004. The characteristics and performance of general practices working under new alternative provider contracts are not well described. We sought to compare the quality of care provided by new entrant providers to that provided by the traditional model of general practice. Open cohort study of English general practices. We used linear regression in cross-sectional and time series analyses, adjusting for practice and population characteristics, to compare quality in practices using alternative provider contracts to traditional practices. We created regression models using practice fixed effects to estimate the impact of practices changing to the new contract type. The English National Health Service. All general practices open from 2008/2009 to 2012/2013. Seventeen established quality indicators--covering clinical effectiveness, efficiency, access and patient experience. In total, 4.1% (347 of 8300) of general practices in England were run by alternative contract providers. These practices tended to be smaller, and serve younger, more diverse and more deprived populations than traditional providers. Practices run by alternative providers performed worse than traditional providers on 15 of 17 indicators after adjusting for practice and population characteristics (p < 0.01 for all). Switching to a new alternative provider contract did not result in improved performance. The introduction of new alternative providers to deliver primary care services in England has not led to improvements in quality and may have resulted in worse care. Regulators should ensure that new entrants to clinical provider markets are performing to adequate standards and at least as well as traditional providers. © The Royal Society of Medicine.

Balance Improvement Effects of Biofeedback Systems with State-of-the-Art Wearable Sensors: A Systematic Review.

PubMed

Ma, Christina Zong-Hao; Wong, Duo Wai-Chi; Lam, Wing Kai; Wan, Anson Hong-Ping; Lee, Winson Chiu-Chun

2016-03-25

Falls and fall-induced injuries are major global public health problems. Balance and gait disorders have been the second leading cause of falls. Inertial motion sensors and force sensors have been widely used to monitor both static and dynamic balance performance. Based on the detected performance, instant visual, auditory, electrotactile and vibrotactile biofeedback could be provided to augment the somatosensory input and enhance balance control. This review aims to synthesize the research examining the effect of biofeedback systems, with wearable inertial motion sensors and force sensors, on balance performance. Randomized and non-randomized clinical trials were included in this review. All studies were evaluated based on the methodological quality. Sample characteristics, device design and study characteristics were summarized. Most previous studies suggested that biofeedback devices were effective in enhancing static and dynamic balance in healthy young and older adults, and patients with balance and gait disorders. Attention should be paid to the choice of appropriate types of sensors and biofeedback for different intended purposes. Maximizing the computing capacity of the micro-processer, while minimizing the size of the electronic components, appears to be the future direction of optimizing the devices. Wearable balance-improving devices have their potential of serving as balance aids in daily life, which can be used indoors and outdoors.

Differences in physical characteristics and response to rehabilitation for patients with hand dystonia: musicians' cramp compared to writers' cramp.

PubMed

McKenzie, Alison L; Goldman, Sarah; Barrango, Cindy; Shrime, Maria; Wong, Tricia; Byl, Nancy

2009-01-01

Pre-Post, Mixed Factorial Trial. Focal hand dystonia is a challenging movement disorder to rehabilitate in musicians and writers. To compare the neuromusculoskeletal characteristics of those with writers' cramp (WC) and musicians' cramp (MC), and evaluate responsiveness to learning-based sensorimotor training. Twenty-seven individuals (14 musicians, 13 writers) participated in 8 weeks of supervised therapy supplemented with a home program. Between-group differences on measures of musculoskeletal (physical), sensory, and motor performance were evaluated at baseline and post-intervention. Subjects with MC had a higher level of functional independence and better range of motion, but less strength in the affected upper limb than those of subjects with WC. Subjects with MC demonstrated greater accuracy on graphesthesia, kinesthesia, and localization at baseline. No between-group differences in motor performance were noted at baseline or post-intervention. Following individually adapted learning-based sensorimotor training, both groups improved in musculoskeletal (physical) parameters, sensory processing, and motor control; however, improvements on certain subtests differed by group. At follow-up, differences in posture, ROM, strength, graphesthesia, and kinesthesia persisted between the groups. Subjects with WC have different physical and performance risk factors compared with those of subjects with MC. Intervention paradigms are efficacious, but variable responses to rehabilitation occur.

Balance Improvement Effects of Biofeedback Systems with State-of-the-Art Wearable Sensors: A Systematic Review

PubMed Central

Ma, Christina Zong-Hao; Wong, Duo Wai-Chi; Lam, Wing Kai; Wan, Anson Hong-Ping; Lee, Winson Chiu-Chun

2016-01-01

Falls and fall-induced injuries are major global public health problems. Balance and gait disorders have been the second leading cause of falls. Inertial motion sensors and force sensors have been widely used to monitor both static and dynamic balance performance. Based on the detected performance, instant visual, auditory, electrotactile and vibrotactile biofeedback could be provided to augment the somatosensory input and enhance balance control. This review aims to synthesize the research examining the effect of biofeedback systems, with wearable inertial motion sensors and force sensors, on balance performance. Randomized and non-randomized clinical trials were included in this review. All studies were evaluated based on the methodological quality. Sample characteristics, device design and study characteristics were summarized. Most previous studies suggested that biofeedback devices were effective in enhancing static and dynamic balance in healthy young and older adults, and patients with balance and gait disorders. Attention should be paid to the choice of appropriate types of sensors and biofeedback for different intended purposes. Maximizing the computing capacity of the micro-processer, while minimizing the size of the electronic components, appears to be the future direction of optimizing the devices. Wearable balance-improving devices have their potential of serving as balance aids in daily life, which can be used indoors and outdoors. PMID:27023558

Dielectric Elastomer Actuators for Soft Wave-Handling Systems.

PubMed

Wang, Tao; Zhang, Jinhua; Hong, Jun; Wang, Michael Yu

2017-03-01

This article presents a soft handling system inspired by the principle of the natural wave (named Wave-Handling system) aiming to offer a soft solution to delicately transport and sort fragile items such as fruits, vegetables, biological tissues in food, and biological industries. The system consists of an array of hydrostatically coupled dielectric elastomer actuators (HCDEAs). Due to the electrostriction property of dielectric elastomers, the handling system can be controlled by electric voltage rather than the cumbersome pneumatic system. To study the working performance of the Wave-Handling system and how the performance can be improved, the basic properties of HCDEA are investigated through experiments. We find that the HCDEA exhibits some delay and hysteretic characteristics when activated by periodic voltage and the characteristics are influenced by the frequency and external force also. All this will affect the performance of the Wave-Handling system. However, the electric control, simple structure, light weight, and low cost of the soft handling system show great potential to move from laboratory to practical application. As a proof of design concept, a simply made prototype of the handling system is controlled to generate a parallel moving wave to manipulate a ball. Based on the experimental results, the improvements and future work are discussed and we believe this work will provide inspiration for soft robotic engineering.

Structural, textural and morphological characteristics of tannins from Acacia mearnsii encapsulated using sol-gel methods: Applications as antimicrobial agents.

PubMed

Dos Santos, Cristiane; Vargas, Álvaro; Fronza, Ney; Dos Santos, João Henrique Zimnoch

2017-03-01

Tannins from Acacia mearnsii were encapsulated using four different sol-gel methods acid (SGAR), basic (SGBR), silicate (SGSR) and non-hydrolytic (SGNHR) routes. The hybrid materials were analyzed using a set of techniques to characterize their structure, texture and morphology. The antimicrobial performance of the encapsulated materials was evaluated against different microorganisms (Staphylococcus aureus, Escherichia coli, Aspergillus niger and Candida sp.). The data showed that the encapsulation route significantly affects the characteristics of the resulting hybrid materials. Better functional performances were obtained using the silicate route, which produced mesoporous materials with a small surface area (0.96m 2 g -1 ) and small particle size (<1nm). These characteristics promoted the gradual release of tannins in an aqueous medium and improved their interactions with microorganisms. Furthermore, the process demonstrated the preservation of tannins after synthesis and increased antimicrobial activity (via a controlled tannin release), as demonstrated by the moderate activity against filamentous fungi and yeast. Copyright © 2016. Published by Elsevier B.V.

Key fuel properties and engine performances of diesel-ethanol blends, using tetrahydrofuran as surfactant additive

NASA Astrophysics Data System (ADS)

Molea, A.; Visuian, P.; Barabás, I.; Suciu, R. C.; Burnete, N. V.

2017-10-01

In this paper there were presented researches related to preparation and characterization of physicochemical properties of diesel-ethanol blends stabilized with tetrahydrofuran as surfactant, in order to be used as fuels in compression ignition engines. The main spray characteristics and engine performances of these blends were evaluated by using AVL Fire software. In the first stage of the studies, commercial diesel was mixed with ethanol, in different concentrations (between 2% and 15% v/v), followed by the addition of tetrahydrofuran (THF) until the blends were miscible, i.e. the blends were stabilized. The experiments were done at room temperature (22 °C). The obtained blends were characterized in order to determine the chemical composition and physicochemical properties, i.e. density, kinematic viscosity, surface tension. UV-Vis spectroscopy was utilized in order to determine a semi-quantitative evaluation regarding the chemical composition of the prepared blends and chemical interaction between diesel, ethanol and THF. Based on the determined properties, the fuel spray characteristics, engine performances and emission characteristics were evaluated by simulation using the AVL Fire software. The obtained results regarding physicochemical properties of blends were compared with diesel. Some improvements were observed when operating with the prepared blends compared to diesel with respect to engine performances and emission characteristics. Based on physicochemical evaluation and computer simulation, it was demonstrated that diesel-ethanol-tetrahydrofuran blends can be used as alternative fuel in compression ignition engines.

A study of prediction methods for the high angle-of-attack aerodynamics of straight wings and fighter aircraft

NASA Technical Reports Server (NTRS)

Mcmillan, O. J.; Mendenhall, M. R.; Perkins, S. C., Jr.

1984-01-01

Work is described dealing with two areas which are dominated by the nonlinear effects of vortex flows. The first area concerns the stall/spin characteristics of a general aviation wing with a modified leading edge. The second area concerns the high-angle-of-attack characteristics of high performance military aircraft. For each area, the governing phenomena are described as identified with the aid of existing experimental data. Existing analytical methods are reviewed, and the most promising method for each area used to perform some preliminary calculations. Based on these results, the strengths and weaknesses of the methods are defined, and research programs recommended to improve the methods as a result of better understanding of the flow mechanisms involved.

Performance regeneration of InGaZnO transistors with ultra-thin channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Binglei; Li, He; Zhang, Xijian, E-mail: zhangxijian@sdu.edu.cn, E-mail: songam@sdu.edu.cn

2015-03-02

Thin-film transistors (TFTs) based on ultra-thin amorphous indium gallium zinc oxide (a-IGZO) semiconductors down to 4 nm were studied motivated by the increasing cost of indium. At and below 5 nm, it was found that the field-effect mobility was severely degraded, the threshold voltage increased, and the output characteristics became abnormal showing no saturated current. By encapsulating a layer of polymethyl methacrylate on the IGZO TFTs, the performance of the 5-nm-thick device was effectively recovered. The devices also showed much higher on/off ratios, improved hysteresis, and normal output characteristic curves as compared with devices not encapsulated. The stability of the encapsulated devicesmore » was also studied over a four month period.« less

Influence of oxygen doping on resistive-switching characteristic of a-Si/c-Si device

NASA Astrophysics Data System (ADS)

Zhang, Jiahua; Chen, Da; Huang, Shihua

2017-12-01

The influence of oxygen doping on resistive-switching characteristics of Ag/a-Si/p+-c-Si device was investigated. By oxygen doping in the growth process of amorphous silicon, the device resistive-switching performances, such as the ON/OFF resistance ratios, yield and stability were improved, which may be ascribed to the significant reduction of defect density because of oxygen incorporation. The device I-V characteristics are strongly dependent on the oxygen doping concentration. As the oxygen doping concentration increases, the Si-rich device gradually transforms to an oxygen-rich device, and the device yield, switching characteristics, and stability may be improved for silver/oxygen-doped a-Si/p+-c-Si device. Finally, the device resistive-switching mechanism was analyzed. Project supported by the Zhejiang Provincial Natural Science Foundation of China (No. LY17F040001), the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (No. KF2015_02), the Open Project Program of National Laboratory for Infrared Physics, Chinese Academy of Sciences (No. M201503), the Zhejiang Provincial Science and Technology Key Innovation Team (No. 2011R50012), and the Zhejiang Provincial Key Laboratory (No. 2013E10022).

Evaluation of a Shoulder Injury Prevention Program in Wheelchair Basketball.

PubMed

Wilroy, Jereme; Hibberd, Elizabeth

2017-11-15

Previous literature has theorized that alterations in shoulder physical characteristics are present in wheelchair athletes and contribute to shoulder pain and injury. Limited empirical evidence is present that evaluates the effectiveness of a shoulder injury prevention program focusing on improving these altered characteristics. To evaluate the effectiveness of a 6-week intervention program at improving characteristics that increases the risk of developing pain or shoulder injury. Pre and post-test. Home-based and controlled laboratory. Seven collegiate wheelchair athletes. Shoulder range of motion (ROM) and scapular muscle strength were assessed, and a 5-minute injury prevention program was taught to participants. Participants completed the intervention 3 times per week for 6 weeks. Following completion of the program, a post-intervention screening was performed. Internal/external rotation ROM, retraction strength, and internal/external rotation strength. Participants experienced a significant improvement in dominant limb shoulder internal rotation ROM (t6=3.56,p=0.012) with an average increase of 11.4° of IR ROM, and a significant improvement in dominant limb shoulder external rotation (ER) ROM (t6=2.79,p=0.032) with an average increase of 8.0° of ER ROM. There were no significant increases in shoulder IR or ER strength and scapular retraction strength (p>0.05). Improvements in ROM have previously been linked to decreases in shoulder pain and injury in other upper-extremity dominant sports by improving scapular kinematics. These results provide evidence that a 6-week strengthening and stretching intervention program may decrease risk factors for shoulder injury in wheelchair athletics.

Leveling the field: addressing health disparities through diabetes disease management.

PubMed

White, Richard O; DeWalt, Darren A; Malone, Robert M; Osborn, Chandra Y; Pignone, Michael P; Rothman, Russell L

2010-01-01

To examine the relationships among patient characteristics, labor inputs, and improvement in glycosylated hemoglobin (A1C) level in a successful primary care-based diabetes disease management program (DDMP). We performed subanalyses to examine the relationships among patient characteristics, labor inputs, and improvement in A1C level within a randomized controlled trial. Control patients received usual care, while intervention patients received usual care plus a comprehensive DDMP. The primary outcome was improvement in A1C level over 12 months stratified by intervention status and patient characteristics. Process outcomes included the number of actions or contacts with patients, time spent with patients, and number of glucose medication titrations or additions. One hundred ninety-three of 217 enrolled patients (88.9%) had complete 12-month followup data. Patients in the intervention group had significantly greater improvement in A1C level than the control group (-2.1% vs -1.2%, P = .007). In multivariate analysis, no significant differences were observed in improvement in A1C level when stratified by age, race/ethnicity, income, or insurance status, and no interaction effect was observed between any covariate and intervention status. Among intervention patients, we observed similar labor inputs regardless of age, race/ethnicity, sex, education, or whether goal A1C level was achieved. Among intervention patients in a successful DDMP, improvement in A1C level was achieved regardless of age, race/ethnicity, sex, income, education, or insurance status. Labor inputs were similar regardless of age, race/ethnicity, sex, or education and may reflect the nondiscriminatory nature of providing algorithm-based disease management care.

Student Buy-In Toward Formative Assessments: The Influence of Student Factors and Importance for Course Success †

PubMed Central

Brazeal, Kathleen R.; Couch, Brian A.

2017-01-01

Formative assessment (FA) techniques, such as pre-class assignments, in-class activities, and post-class homework, have been shown to improve student learning. While many students find these techniques beneficial, some students may not understand how they support learning or may resist their implementation. Improving our understanding of FA buy-in has important implications, since buy-in can potentially affect whether students fully engage with and learn from FAs. We investigated FAs in 12 undergraduate biology courses to understand which student characteristics influenced buy-in toward FAs and whether FA buy-in predicted course success. We administered a mid-semester survey that probed student perceptions toward several different FA types, including activities occurring before, during, and after class. The survey included closed-ended questions aligned with a theoretical framework outlining key FA objectives. We used factor analysis to calculate an overall buy-in score for each student and general linear models to determine whether certain characteristics were associated with buy-in and whether buy-in predicted exam scores and course grades. We found that unfixed student qualities, such as perceptions, behaviors, and beliefs, consistently predicted FA buy-in, while fixed characteristics, including demographics, previous experiences, and incoming performance metrics, had more limited effects. Importantly, we found that higher buy-in toward most FA types predicted higher exam scores and course grades, even when controlling for demographic characteristics and previous academic performance. We further discuss steps that instructors can take to maximize student buy-in toward FAs. PMID:28512523

Organizational performance impacting patient satisfaction in Ontario hospitals: a multilevel analysis

PubMed Central

2013-01-01

Background Patient satisfaction in health care constitutes an important component of organizational performance in the hospital setting. Satisfaction measures have been developed and used to evaluate and improve hospital performance, quality of care and physician practice. In order to direct improvement strategies, it is necessary to evaluate both individual and organizational factors that can impact patients’ perception of care. The study aims were to determine the dimensions of patient satisfaction, and to analyze the individual and organizational determinants of satisfaction dimensions in hospitals. Methods We used patient and hospital survey data as well as administrative data collected for a 2008 public hospital report in Ontario, Canada. We evaluated the clustering of patient survey items with exploratory factor analysis and derived plausible dimensions of satisfaction. A two-level multivariate model was fitted to analyze the determinants of satisfaction. Results We found eight satisfaction factors, with acceptable to good level of loadings and good reliability. More than 95% of variation in patient satisfaction scores was attributable to patient-level variation, with less than 5% attributable to hospital-level variation. The hierarchical models explain 5 to 17% of variation at the patient level and up to 52% of variation between hospitals. Individual patient characteristics had the strongest association with all dimensions of satisfaction. Few organizational performance indicators are associated with patient satisfaction and significant determinants differ according to the satisfaction dimension. Conclusions The research findings highlight the importance of adjusting for both patient-level and organization-level characteristics when evaluating patient satisfaction. Better understanding and measurement of organization-level activities and processes associated with patient satisfaction could contribute to improved satisfaction ratings and care quality. PMID:24304888

Indonesian name matching using machine learning supervised approach

NASA Astrophysics Data System (ADS)

Alifikri, Mohamad; Arif Bijaksana, Moch.

2018-03-01

Most existing name matching methods are developed for English language and so they cover the characteristics of this language. Up to this moment, there is no specific one has been designed and implemented for Indonesian names. The purpose of this thesis is to develop Indonesian name matching dataset as a contribution to academic research and to propose suitable feature set by utilizing combination of context of name strings and its permute-winkler score. Machine learning classification algorithms is taken as the method for performing name matching. Based on the experiments, by using tuned Random Forest algorithm and proposed features, there is an improvement of matching performance by approximately 1.7% and it is able to reduce until 70% misclassification result of the state of the arts methods. This improving performance makes the matching system more effective and reduces the risk of misclassified matches.

Engineering characterisation of epoxidized natural rubber-modified hot-mix asphalt

PubMed Central

Al-Mansob, Ramez A.; Ismail, Amiruddin; Yusoff, Nur Izzi Md.; Rahmat, Riza Atiq O. K.; Borhan, Muhamad Nazri; Albrka, Shaban Ismael; Azhari, Che Husna; Karim, Mohamed Rehan

2017-01-01

Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR–asphalt mixes prepared using the wet process. Mechanical testing on the ENR–asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR–asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR–asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress. PMID:28182724

Engineering characterisation of epoxidized natural rubber-modified hot-mix asphalt.

PubMed

Al-Mansob, Ramez A; Ismail, Amiruddin; Yusoff, Nur Izzi Md; Rahmat, Riza Atiq O K; Borhan, Muhamad Nazri; Albrka, Shaban Ismael; Azhari, Che Husna; Karim, Mohamed Rehan

2017-01-01

Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.

A cable-driven locomotor training system for restoration of gait in human SCI.

PubMed

Wu, Ming; Hornby, T George; Landry, Jill M; Roth, Heidi; Schmit, Brian D

2011-02-01

A novel cable-driven robotic locomotor training system was developed to provide compliant assistance/resistance forces to the legs during treadmill training in patients with incomplete spinal cord injury (SCI). Eleven subjects with incomplete SCI were recruited to participate in two experiments to test the feasibility of the robotic gait training system. Specifically, 10 subjects participated in one experimental session to test the characteristics of the robotic gait training system and one subject participated in repeated testing sessions over 8 weeks with the robotic device to test improvements in locomotor function. Limb kinematics were recorded in one experiment to evaluate the system characteristics of the cable-driven locomotor trainer and the overground gait speed and 6 min walking distance were evaluated at pre, 4 and 8 weeks post treadmill training of a single subject as well. The results indicated that the cable driven robotic gait training system improved the kinematic performance of the leg during treadmill walking and had no significant impact on the variability of lower leg trajectory, suggesting a high backdrivability of the cable system. In addition, results from a patient with incomplete SCI indicated that prolonged robotic gait training using the cable robot improved overground gait speed. Results from this study suggested that a cable driven robotic gait training system is effective in improving leg kinematic performance, yet allows variability of gait kinematics. Thus, it seems feasible to improve the locomotor function in human SCI using this cable driven robotic system, warranting testing with a larger group of patients. Copyright © 2010 Elsevier B.V. All rights reserved.

Is intracytoplasmic morphologically selected sperm injection (IMSI) beneficial in the first ART cycle? a multicentric randomized controlled trial.

PubMed

Leandri, R D; Gachet, A; Pfeffer, J; Celebi, C; Rives, N; Carre-Pigeon, F; Kulski, O; Mitchell, V; Parinaud, J

2013-09-01

Intracytoplasmic morphologically selected sperm injection (IMSI), by selecting spermatozoa at high magnification improves the outcome of intracytoplasmic sperm injection (ICSI) mainly after several failures. However, only few monocentric randomized studies are available and they do not analyse results as a function of sperm characteristics. In 255 couples attempting their first assisted reproductive technology (ART) attempt for male infertility (motile sperm count <1×10⁶ after sperm selection, but at least 3×10⁶ spermatozoa per ejaculate to allow a detailed analysis of sperm characteristics), a prospective randomized trial was performed to compare the clinical outcomes of IMSI and ICSI and to evaluate the influence of sperm characteristics on these outcomes. IMSI did not provide any significant improvement in the clinical outcomes compared with ICSI neither for implantation (24% vs. 23%), nor clinical pregnancy (31% vs. 33%) nor live birth rates (27% vs. 30%). Moreover, the results of IMSI were similar to the ICSI ones whatever the degree of sperm DNA fragmentation, nuclear immaturity and sperm morphology. These results show that IMSI instead of ICSI has no advantage in the first ART attempts. However, this does not rule out IMSI completely and more randomized trials must be performed especially regarding patients carrying severe teratozoospermia, or high sperm DNA fragmentation levels or having previous ICSI failures. © 2013 American Society of Andrology and European Academy of Andrology.

Physical Characteristics Underpinning Repetitive Lunging in Fencing.

PubMed

Turner, Anthony N; Marshall, Geoff; Phillips, James; Noto, Angelo; Buttigieg, Conor; Chavda, Shyam; Downing, William; Atlay, Nathan; Dimitriou, Lygeri; Kilduff, Laim

2016-11-01

Turner, AN, Marshall, G, Phillips, J, Noto, A, Buttigieg, C, Chavda, S, Downing, W, Atlay, N, Dimitriou, L, and Kilduff, L. Physical characteristics underpinning repetitive lunging in fencing. J Strength Cond Res 30(11): 3134-3139, 2016-Given the repetitive demand to execute lunging and changes in direction within fencing, the ability to sustain these at maximal capacity is fundamental to performance. The aim of this study was threefold. First, to provide normative values for this variable referred to as repeat lunge ability (RLA) and second to identify the physical characteristics that underpin it. Third, was to establish if a cause and effect relationship existed by training the associated characteristics. Assessment of lower-body power, reactive strength, speed, change of direction speed (CODS), and a sport-specific RLA were conducted on senior and junior elite male fencers (n = 36). Fencers were on average (±SD) 18.9 ± 3.2 years of age, 174.35 ± 10.42 cm tall, 70.67 ± 7.35 kg in mass, and 8.5 ± 4.2 years fencing experience. The RLA test had average work times of 16.03 ± 1.40 seconds and demonstrated "large" to "very large" associations with all tested variables, but in particular CODS (r = 0.70) and standing broad jump (SBJ; r = -0.68). Through linear regression analysis, these also provided a 2-predictor model accounting for 61% of the common variance associated with RLA. A cause and effect relationship with SBJ and CODS was confirmed by the training group, where RLA performance in these fencers improved from 15.80 ± 1.07 to 14.90 ± 0.86 seconds, with the magnitude of change reported as "moderate" (effect size (ES) = 0.93). Concurrent improvements were also noted in both SBJ (216.86 ± 17.15 vs. 221.71 ± 17.59 cm) and CODS (4.44 ± 0.29 vs. 4.31 ± 0.09 seconds) and while differences were only significant in SBJ, magnitudes of change were classed as "small" (ES = 0.28) and "moderate" (ES = 0.61), respectively. In conclusion, to improve RLA strength and conditioning coaches should focus on improving lower-body power and reactive strength, noting that jump training and plyometrics designed to enhance horizontal propulsion may be most effective, and translate to improvement in CODS also.

An Examination of School Choice and Fifth Grade Science Achievement in Florida

NASA Astrophysics Data System (ADS)

McLarnon, Tara Lynn

Over the past 20 years, a movement to offer greater access and choice in public education has begun to challenge the traditional attendance boundary school system. Public school choice provides an opportunity for parents who do not have the resources to change attendance boundaries but who want additional public school options. Proponents argue that increased competition incentivizes all schools to improve performance. The purpose of this study was to determine whether there were any potential relationships among school choice options and other inputs such as student characteristics when looking at student science achievement. Based on an education production function model, the study focused on the specific output of performance. A conceptual model looking at common inputs related to the outcome of student performance, identified five groups of inputs: school type, student characteristics, learning needs, school characteristics, and teacher quality. Rather than look across states, where policies affecting student performance differ, this study looked exclusively at one large state population. Subjects of the study were fifth grade students in the state of Florida. Utilizing three years of state science assessment data, the roles of school type, selected student demographics, and ELL status were examined using logistic regression and ordinary least squares analysis. Results indicated that, while some subpopulations of students performed better in different school types, school type alone was not a strong predictor of student science achievement.

A Novel Wide-Area Backup Protection Based on Fault Component Current Distribution and Improved Evidence Theory

PubMed Central

Zhang, Zhe; Kong, Xiangping; Yin, Xianggen; Yang, Zengli; Wang, Lijun

2014-01-01

In order to solve the problems of the existing wide-area backup protection (WABP) algorithms, the paper proposes a novel WABP algorithm based on the distribution characteristics of fault component current and improved Dempster/Shafer (D-S) evidence theory. When a fault occurs, slave substations transmit to master station the amplitudes of fault component currents of transmission lines which are the closest to fault element. Then master substation identifies suspicious faulty lines according to the distribution characteristics of fault component current. After that, the master substation will identify the actual faulty line with improved D-S evidence theory based on the action states of traditional protections and direction components of these suspicious faulty lines. The simulation examples based on IEEE 10-generator-39-bus system show that the proposed WABP algorithm has an excellent performance. The algorithm has low requirement of sampling synchronization, small wide-area communication flow, and high fault tolerance. PMID:25050399

Microwave-assisted acid pretreatment of alkali lignin: Effect on characteristics and pyrolysis behavior.

PubMed

Duan, Dengle; Ruan, Roger; Wang, Yunpu; Liu, Yuhuan; Dai, Leilei; Zhao, Yunfeng; Zhou, Yue; Wu, Qiuhao

2018-03-01

This study performed microwave-assisted acid pretreatment on pure lignin. The effects of microwave temperature, microwave time, and hydrochloric acid concentration on characteristics and pyrolysis behavior of lignin were examined. Results of ultimate analysis revealed better properties of all pretreated samples than those of raw lignin. Fourier transform infrared spectroscopy analysis showed breakage of βO4 bond and aliphatic side chain, decrease in OH groups, and formation of CO groups in pretreatment. Microwave temperature exerted more significant influence on lignin structure. Thermal stability of treated lignin was improved and insensitive to short microwave time and acid concentration under mild conditions. Resulting from improved alkyl-phenols and decreased alkoxy-phenols, microwave-assisted acid pretreatment of lignin yielded bio-oil with excellent quality. Total yield of phenols in pyrolysis vapors (200 °C) improved to 14.15%, whereas that of guaiacols decreased to 22.36%. This study shows that microwave-assisted acid pretreatment is a promising technology for lignin conversion. Copyright © 2017 Elsevier Ltd. All rights reserved.

A novel approach for the improvement of electrostatic behaviour of physically doped TFET using plasma formation and shortening of gate electrode with hetero-gate dielectric

NASA Astrophysics Data System (ADS)

Soni, Deepak; Sharma, Dheeraj; Aslam, Mohd.; Yadav, Shivendra

2018-04-01

This article presents a new device configuration to enhance current drivability and suppress negative conduction (ambipolar conduction) with improved RF characteristics of physically doped TFET. Here, we used a new approach to get excellent electrical characteristics of hetero-dielectric short gate source electrode TFET (HD-SG SE-TFET) by depositing a metal electrode of 5.93 eV work function over the heavily doped source (P+) region. Deposition of metal electrode induces the plasma (thin layer) of holes under the Si/HfO2 interface due to work function difference of metal and semiconductor. Plasma layer of holes is advantageous to increase abruptness as well as decrease the tunneling barrier at source/channel junction for attaining higher tunneling rate of charge carriers (i.e., electrons), which turns into 86.66 times higher ON-state current compared with the conventional physically doped TFET (C-TFET). Along with metal electrode deposition, gate electrode is under-lapped for inducing asymmetrical concentration of charge carriers in the channel region, which is helpful for widening the tunneling barrier width at the drain/channel interface. Consequently, HD-SG SE-TFET shows suppression of ambipolar behavior with reduction in gate-to-drain capacitance which is beneficial for improvement in RF performance. Furthermore, the effectiveness of hetero-gate dielectric concept has been used for improving the RF performance. Furthermore, reliability of C-TFET and proposed structures has been confirmed in term of linearity.

Global modeling of land water and energy balances. Part II: Land-characteristic contributions to spatial variability

USGS Publications Warehouse

Milly, P.C.D.; Shmakin, A.B.

2002-01-01

Land water and energy balances vary around the globe because of variations in amount and temporal distribution of water and energy supplies and because of variations in land characteristics. The former control (water and energy supplies) explains much more variance in water and energy balances than the latter (land characteristics). A largely untested hypothesis underlying most global models of land water and energy balance is the assumption that parameter values based on estimated geographic distributions of soil and vegetation characteristics improve the performance of the models relative to the use of globally constant land parameters. This hypothesis is tested here through an evaluation of the improvement in performance of one land model associated with the introduction of geographic information on land characteristics. The capability of the model to reproduce annual runoff ratios of large river basins, with and without information on the global distribution of albedo, rooting depth, and stomatal resistance, is assessed. To allow a fair comparison, the model is calibrated in both cases by adjusting globally constant scale factors for snow-free albedo, non-water-stressed bulk stomatal resistance, and critical root density (which is used to determine effective root-zone depth). The test is made in stand-alone mode, that is, using prescribed radiative and atmospheric forcing. Model performance is evaluated by comparing modeled runoff ratios with observed runoff ratios for a set of basins where precipitation biases have been shown to be minimal. The withholding of information on global variations in these parameters leads to a significant degradation of the capability of the model to simulate the annual runoff ratio. An additional set of optimization experiments, in which the parameters are examined individually, reveals that the stomatal resistance is, by far, the parameter among these three whose spatial variations add the most predictive power to the model in stand-alone mode. Further single-parameter experiments with surface roughness length, available water capacity, thermal conductivity, and thermal diffusivity show very little sensitivity to estimated global variations in these parameters. Finally, it is found that even the constant-parameter model performance exceeds that of the Budyko and generalized Turc-Pike water-balance equations, suggesting that the model benefits also from information on the geographic variability of the temporal structure of forcing.

Characteristics and outcomes of America's lowest-performing hospitals: an analysis of acute myocardial infarction hospital care in the United States.

PubMed

Popescu, Ioana; Werner, Rachel M; Vaughan-Sarrazin, Mary S; Cram, Peter

2009-05-01

Studies suggest that most hospitals now have relatively high adherence with recommended acute myocardial infarction (AMI) process measures. Little is known about hospitals with consistently poor adherence with AMI process measures and whether these hospitals also have increased patient mortality. We conducted a retrospective study of 2761 US hospitals reporting AMI process measures to the Center for Medicare and Medicaid Services Hospital Compare database during 2004 to 2006 that could be linked to 2005 Medicare Part A data. The main outcome measures were hospitals' combined compliance with 5 AMI measures (aspirin and beta-blocker on admission and discharge and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use at discharge for patients with left ventricular dysfunction) and risk-adjusted 30-day mortality for 2005. We stratified hospitals into those with low AMI adherence (ranked in the lowest decile for AMI adherence for 3 consecutive years [2004-2006, n=105]), high adherence (ranked in the top decile for 3 consecutive years [n=63]), and intermediate adherence (all others [n=2593]). Mean AMI performance varied significantly across low-, intermediate-, and high-performing hospitals (mean score, 68% versus 92% versus 99%, P<0.001). Low-performing hospitals were more likely than intermediate- and high-performing hospitals to be safety-net providers (19.2% versus 11.0% versus 6.4%; P=0.005). Low-performing hospitals had higher unadjusted 30-day mortality rates (23.6% versus 17.8% versus 14.9%; P<0.001). These differences persisted after adjustment for patient characteristics (16.3% versus 16.0% versus 15.7%; P=0.02). Consistently low-performing hospitals differ substantially from other US hospitals. Targeting quality improvement efforts toward these hospitals may offer an attractive opportunity for improving AMI outcomes.

Design Characteristics Influence Performance of Clinical Prediction Rules in Validation: A Meta-Epidemiological Study

PubMed Central

Ban, Jong-Wook; Emparanza, José Ignacio; Urreta, Iratxe; Burls, Amanda

2016-01-01

Background Many new clinical prediction rules are derived and validated. But the design and reporting quality of clinical prediction research has been less than optimal. We aimed to assess whether design characteristics of validation studies were associated with the overestimation of clinical prediction rules’ performance. We also aimed to evaluate whether validation studies clearly reported important methodological characteristics. Methods Electronic databases were searched for systematic reviews of clinical prediction rule studies published between 2006 and 2010. Data were extracted from the eligible validation studies included in the systematic reviews. A meta-analytic meta-epidemiological approach was used to assess the influence of design characteristics on predictive performance. From each validation study, it was assessed whether 7 design and 7 reporting characteristics were properly described. Results A total of 287 validation studies of clinical prediction rule were collected from 15 systematic reviews (31 meta-analyses). Validation studies using case-control design produced a summary diagnostic odds ratio (DOR) 2.2 times (95% CI: 1.2–4.3) larger than validation studies using cohort design and unclear design. When differential verification was used, the summary DOR was overestimated by twofold (95% CI: 1.2 -3.1) compared to complete, partial and unclear verification. The summary RDOR of validation studies with inadequate sample size was 1.9 (95% CI: 1.2 -3.1) compared to studies with adequate sample size. Study site, reliability, and clinical prediction rule was adequately described in 10.1%, 9.4%, and 7.0% of validation studies respectively. Conclusion Validation studies with design shortcomings may overestimate the performance of clinical prediction rules. The quality of reporting among studies validating clinical prediction rules needs to be improved. PMID:26730980

Design Characteristics Influence Performance of Clinical Prediction Rules in Validation: A Meta-Epidemiological Study.

PubMed

Ban, Jong-Wook; Emparanza, José Ignacio; Urreta, Iratxe; Burls, Amanda

2016-01-01

Many new clinical prediction rules are derived and validated. But the design and reporting quality of clinical prediction research has been less than optimal. We aimed to assess whether design characteristics of validation studies were associated with the overestimation of clinical prediction rules' performance. We also aimed to evaluate whether validation studies clearly reported important methodological characteristics. Electronic databases were searched for systematic reviews of clinical prediction rule studies published between 2006 and 2010. Data were extracted from the eligible validation studies included in the systematic reviews. A meta-analytic meta-epidemiological approach was used to assess the influence of design characteristics on predictive performance. From each validation study, it was assessed whether 7 design and 7 reporting characteristics were properly described. A total of 287 validation studies of clinical prediction rule were collected from 15 systematic reviews (31 meta-analyses). Validation studies using case-control design produced a summary diagnostic odds ratio (DOR) 2.2 times (95% CI: 1.2-4.3) larger than validation studies using cohort design and unclear design. When differential verification was used, the summary DOR was overestimated by twofold (95% CI: 1.2 -3.1) compared to complete, partial and unclear verification. The summary RDOR of validation studies with inadequate sample size was 1.9 (95% CI: 1.2 -3.1) compared to studies with adequate sample size. Study site, reliability, and clinical prediction rule was adequately described in 10.1%, 9.4%, and 7.0% of validation studies respectively. Validation studies with design shortcomings may overestimate the performance of clinical prediction rules. The quality of reporting among studies validating clinical prediction rules needs to be improved.

Engineering and organizational solutions for improvement of engineering and economic characteristics of the TPE-216 boilers equipped with MV-3300/800/490 pulverizing fans

NASA Astrophysics Data System (ADS)

Kirillov, M. V.; Safronov, P. G.

2014-07-01

Efficiency of coal-fired boilers is determined in many respects by optimal operation of the coal-pulverizing plants that are increasingly frequently equipped with pulverizing fans. By an example of retrofitted MV-3300/800/490 pulverizing fans, the effects of different factors on the performance and economic efficiency of the coal-pulverizing plants are analyzed. The experience gained in retrofitting MV-3300/800/490 pulverizing fans by introducing the three-crusher operation mode of a TPE-216 boiler employing the internal recirculation and a blading device in the classifier was also studied. Optimization of the boiler's operation mode was made when switching over from the four-crusher to the three-crusher mode, which considerably improved the engineering and economic characteristics.

Linear combination methods to improve diagnostic/prognostic accuracy on future observations

PubMed Central

Kang, Le; Liu, Aiyi; Tian, Lili

2014-01-01

Multiple diagnostic tests or biomarkers can be combined to improve diagnostic accuracy. The problem of finding the optimal linear combinations of biomarkers to maximise the area under the receiver operating characteristic curve has been extensively addressed in the literature. The purpose of this article is threefold: (1) to provide an extensive review of the existing methods for biomarker combination; (2) to propose a new combination method, namely, the nonparametric stepwise approach; (3) to use leave-one-pair-out cross-validation method, instead of re-substitution method, which is overoptimistic and hence might lead to wrong conclusion, to empirically evaluate and compare the performance of different linear combination methods in yielding the largest area under receiver operating characteristic curve. A data set of Duchenne muscular dystrophy was analysed to illustrate the applications of the discussed combination methods. PMID:23592714

Content validation of the operational definitions of the nursing diagnoses of activity intolerance, excess fluid volume, and decreased cardiac output in patients with heart failure.

PubMed

de Souza, Vanessa; Zeitoun, Sandra Salloum; Lopes, Camila Takao; de Oliveira, Ana Paula Dias; Lopes, Juliana de Lima; de Barros, Alba Lucia Botura Leite

2014-06-01

To consensually validate the operational definitions of the nursing diagnoses activity intolerance, excessive fluid volume, and decreased cardiac output in patients with decompensated heart failure. Consensual validation was performed in two stages: analogy by similarity of defining characteristics, and development of operational definitions and validation with experts. A total of 38 defining characteristics were found. Operational definitions were developed and content-validated. One hundred percent of agreement was achieved among the seven experts after five rounds. "Ascites" was added in the nursing diagnosis excessive fluid volume. The consensual validation improves interpretation of human response, grounding the selection of nursing interventions and contributing to improved nursing outcomes. Support the assessment of patients with decompensated heart failure. © 2013 NANDA International.

Synthesis of branched polymers under continuous-flow microprocess: an improvement of the control of macromolecular architectures.

PubMed

Bally, Florence; Serra, Christophe A; Brochon, Cyril; Hadziioannou, Georges

2011-11-15

Polymerization reactions can benefit from continuous-flow microprocess in terms of kinetics control, reactants mixing or simply efficiency when high-throughput screening experiments are carried out. In this work, we perform for the first time the synthesis of branched macromolecular architecture through a controlled/'living' polymerization technique, in tubular microreactor. Just by tuning process parameters, such as flow rates of the reactants, we manage to generate a library of polymers with various macromolecular characteristics. Compared to conventional batch process, polymerization kinetics shows a faster initiation step and more interestingly an improved branching efficiency. Due to reduced diffusion pathway, a characteristic of microsystems, it is thus possible to reach branched polymers exhibiting a denser architecture, and potentially a higher functionality for later applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of formulation excipients and physical characteristics of inhalation dry powders on their aerosolization performance.

PubMed

Bosquillon, C; Lombry, C; Préat, V; Vanbever, R

2001-02-23

The objective of this study was to determine the effects of formulation excipients and physical characteristics of inhalation particles on their in vitro aerosolization performance, and thereby to maximize their respirable fraction. Dry powders were produced by spray-drying using excipients that are FDA-approved for inhalation as lactose, materials that are endogenous to the lungs as albumin and dipalmitoylphosphatidylcholine (DPPC); and/or protein stabilizers as trehalose or mannitol. Dry powders suitable for deep lung deposition, i.e. with an aerodynamic diameter of individual particles <3 microm, were prepared. They presented 0.04--0.25 g/cm(3) bulk tap densities, 3--5 microm geometric particle sizes, up to 90% emitted doses and 50% respirable fractions in the Andersen cascade impactor using a Spinhaler inhaler device. The incorporation of lactose, albumin and DPPC in the formulation all improved the aerosolization properties, in contrast to trehalose and the mannitol which decreased powder flowability. The relative proportion of the excipients affected aerosol performance as well. The lower the bulk powder tap density, the higher the respirable fraction. Optimization of in vitro aerosolization properties of inhalation dry powders can be achieved by appropriately selecting composition and physical characteristics of the particles.

Academic trajectories of newcomer immigrant youth.

PubMed

Suárez-Orozco, Carola; Gaytán, Francisco X; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

2010-05-01

Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve analysis revealed that although some newcomer students performed at high or improving levels over time, others showed diminishing performance. Multinomial logistic regressions identified significant group differences in academic trajectories, particularly between the high-achieving youth and the other groups. In keeping with ecological-developmental and stage-environment fit theories, School Characteristics (school segregation rate, school poverty rate, and student perceptions of school violence), Family Characteristics (maternal education, parental employment, and household structure), and Individual Characteristics (academic English proficiency, academic engagement, psychological symptoms, gender, and 2 age-related risk factors, number of school transitions and being overaged for grade placement) were associated with different trajectories of academic performance. A series of case studies triangulate many of the quantitative findings as well as illuminate patterns that were not detected in the quantitative data. Thus, the mixed-methods approach sheds light on the cumulative developmental challenges that immigrant students face as they adjust to their new educational settings. 2010 APA, all rights reserved

A static investigation of several STOVL exhaust system concepts

NASA Technical Reports Server (NTRS)

Romine, B. M., Jr.; Meyer, B. E.; Re, R. J.

1989-01-01

A static cold flow scale model test was performed in order to determine the internal performance characteristics of various STOVL exhaust systems. All of the concepts considered included a vectorable cruise nozzle and a separate vectorable vertical thrust ventral nozzle mounted on the tailpipe. The two ventral nozzle configurations tested featured vectorable constant thickness cascade vanes for area control and improved performance during transition and vertical lift flight. The best transition performance was achieved using a butterfly door type ventral nozzle and a pitch vectoring 2DCD or axisymmetric cruise nozzle. The clamshell blocker type of ventral nozzle had reduced transition performance due to the choking of the tailpipe flow upstream of the cruise nozzle.

Performance seeking control (PSC) for the F-15 highly integrated digital electronic control (HIDEC) aircraft

NASA Technical Reports Server (NTRS)

Orme, John S.

1995-01-01

The performance seeking control algorithm optimizes total propulsion system performance. This adaptive, model-based optimization algorithm has been successfully flight demonstrated on two engines with differing levels of degradation. Models of the engine, nozzle, and inlet produce reliable, accurate estimates of engine performance. But, because of an observability problem, component levels of degradation cannot be accurately determined. Depending on engine-specific operating characteristics PSC achieves various levels performance improvement. For example, engines with more deterioration typically operate at higher turbine temperatures than less deteriorated engines. Thus when the PSC maximum thrust mode is applied, for example, there will be less temperature margin available to be traded for increasing thrust.

A High Intensity Interval Training (HIIT)-Based Running Plan Improves Athletic Performance by Improving Muscle Power.

PubMed

García-Pinillos, Felipe; Cámara-Pérez, Jose C; Soto-Hermoso, Víctor M; Latorre-Román, Pedro Á

2017-01-01

García-Pinillos, F, Cámara-Pérez, JC, Soto-Hermoso, VM, and Latorre-Román, PÁ. A High Intensity Interval Training (HIIT)-based running plan improves athletic performance by improving muscle power. J Strength Cond Res 31(1): 146-153, 2017-This study aimed to examine the effect of a 5-week high-intensity intermittent training (HIIT)-based running plan on athletic performance and to compare the physiological and neuromuscular responses during a sprint-distance triathlon before and after the HIIT period. Thirteen triathletes were matched into 2 groups: the experimental group (EG) and the control group (CG). The CG was asked to maintain their normal training routines, whereas the EG maintained only their swimming and cycling routines and modified their running routine. Participants completed a sprint-distance triathlon before (pretest) and after (posttest) the intervention period. In both pretest and posttest, the participants performed 4 jumping tests: before the race (baseline), postswim, postcycling, and postrun. Additionally, heart rate was monitored (HRmean), whereas rate of perceived exertion (RPE) and blood lactate accumulation (BLa) were registered after the race. No significant differences (p ≥ 0.05) between groups were found before HIIT intervention (at pretest). Significant group-by-training interactions were found in vertical jumping ability and athletic performance: the EG improved jumping performance (∼6-9%, p ≤ 0.05, effect size (ES) > 0.7), swimming performance (p = 0.013, ES = 0.438), and running time (p = 0.001, ES = 0.667) during the competition, whereas the CG remained unchanged (p ≥ 0.05, ES < 0.4). No changes (p ≥ 0.05, ES < 0.4) were observed in RPE, HRmean, and BLa. A linear regression analysis showed that ΔCMJ predicted both the ΔRu_time (R = 0.559; p = 0.008) and the ΔOverall_time (R = 0.391; p = 0.048). This low-volume, HIIT-based running plan combined with the high training volumes of these triathletes in swimming and cycling improved athletic performance during a sprint-distance triathlon. This improvement may be due to improved neuromuscular characteristics that were transferred into improved muscle power and work economy.

The Collegiate Learning Assessment: Setting Standards for Performance at a College or University. Technical Report

ERIC Educational Resources Information Center

Hardison, Chaitra M.; Vilamovska, Anna-Marie

2009-01-01

The Collegiate Learning Assessment (CLA) is a measure of how much students' critical thinking improves after attending college or university. This report illustrates how institutions can set their own standards on the CLA using a method that is appropriate for the CLA's unique characteristics. The authors examined evidence of reliability and…

Web-Based Cognitive Apprenticeship Model for Improving Pre-Service Teachers' Performances and Attitudes towards Instructional Planning: Design and Field Experiment

ERIC Educational Resources Information Center

Liu, Tzu-Chien

2005-01-01

Instructional planning is an essential professional activity often used by teachers. However, some characteristics of existing university-based teacher education programs may hamper pre-service teachers' learning of instructional planning. Thus, this study adopts the cognitive apprenticeship as a theoretical foundation to construct a web-based…

Teaching Transformational Leadership to Undergraduate Agricultural Leadership Students: Using the Personality Trait of Agreeableness to Improve Understanding

ERIC Educational Resources Information Center

Lamm, Kevan W.; Carter, Hannah S.; Stedman, Nicole L. P.; Lamm, Alexa J.

2014-01-01

Training undergraduate agricultural students to be strong, positive leaders will have a large impact on the industries they work within and therefore should be of utmost importance to agricultural educators. Transformational leaders (TL) tend to have higher performing, more satisfied teams; consequently, development of TL characteristics should…

Dynamic Transfers Of Tasks Among Computers

NASA Technical Reports Server (NTRS)

Liu, Howard T.; Silvester, John A.

1989-01-01

Allocation scheme gives jobs to idle computers. Ideal resource-sharing algorithm should have following characteristics: Dynamics, decentralized, and heterogeneous. Proposed enhanced receiver-initiated dynamic algorithm (ERIDA) for resource sharing fulfills all above criteria. Provides method balancing workload among hosts, resulting in improvement in response time and throughput performance of total system. Adjusts dynamically to traffic load of each station.

Multi-mission Ni-H2 battery cell for the 1990's

NASA Technical Reports Server (NTRS)

Miller, Lee; Brill, Jack; Dodson, Gary

1989-01-01

A sufficient production, test and operational database is now available to permit design technology optimization for the next decade. The evolved battery cell design features standardized technology intended to support multiple type missions (e.g., both GEO and LEO). Design analyses and validation test cells demonstrate improved performance plus attractive specific-energy characteristics will be achieved.

Change Facilitators: In Search of Understanding Their Role. Research on the Improvement Process in Schools and Colleges.

ERIC Educational Resources Information Center

Rutherford, William L.; And Others

This information analysis paper examines (1) the characteristics associated with effective change facilitators and (2) the concept of "style" and its value in describing and understanding leadership performance and the role of change facilitators in particular. Three bodies of literature are highlighted and summarized in pursuit of…

Review of Research on Classroom Communication Patterns, Leading to Improved Student Performance.

ERIC Educational Resources Information Center

Hall, Vernon C.

This is a review of studies designed to assess the attributes of teacher-student interaction predicted to be correlated with student achievement. The paper includes: (1) a summary review of the types of teacher characteristics found to be correlated with student achievement and attitude; (2) a summary of the research done using the Flanders…