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Sample records for optimum performance characteristics

  1. Optimum Evaluation of Thermal Performance Characteristics of Micro Heat Pipe using the Hadamard Matrix Design Technique

    Directory of Open Access Journals (Sweden)

    Achebo, J.I

    2013-06-01

    Full Text Available Micro heat pipes are on increasing demand as a result of current advances in technology consequently leading to a concomitant demand for continued research on how their thermal performance could be optimized; hence this study. The Hadamard matrix design approach was used to optimize the input parameters which generated an optimum combination of a 90o inclination angle, 8.70W heat input, and a 0.3 l/min coolant flow rate, these values match with the combination in sample trial 2. Further investigation revealed that sample trial 2 has a thermal resistance of 3.8oC/W with a threshold overall heat transfer coefficient of 750W/m2 oC

  2. Achieving optimum diffraction based overlay performance

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee; Coogans, Martyn; Fuchs, Andreas; Ponomarenko, Mariya; van der Schaar, Maurits; Vanoppen, Peter

    2010-03-01

    Diffraction Based Overlay (DBO) metrology has been shown to have significantly reduced Total Measurement Uncertainty (TMU) compared to Image Based Overlay (IBO), primarily due to having no measurable Tool Induced Shift (TIS). However, the advantages of having no measurable TIS can be outweighed by increased susceptibility to WIS (Wafer Induced Shift) caused by target damage, process non-uniformities and variations. The path to optimum DBO performance lies in having well characterized metrology targets, which are insensitive to process non-uniformities and variations, in combination with optimized recipes which take advantage of advanced DBO designs. In this work we examine the impact of different degrees of process non-uniformity and target damage on DBO measurement gratings and study their impact on overlay measurement accuracy and precision. Multiple wavelength and dual polarization scatterometry are used to characterize the DBO design performance over the range of process variation. In conclusion, we describe the robustness of DBO metrology to target damage and show how to exploit the measurement capability of a multiple wavelength, dual polarization scatterometry tool to ensure the required measurement accuracy for current and future technology nodes.

  3. Optimum performance characteristics of a conduction channel

    Energy Technology Data Exchange (ETDEWEB)

    Okulov, N.A.

    1978-01-01

    Steady laminar flow of an incompressible viscous and electrically conducting fluid is considered in an infinitely long cylindrical conduction channel. A set of permanent magnets outside produces a transverse magnetic field which does not vary over the channel length. An external electric dc generator or load maintains on the channel-fluid boundary a distribution of electric potential which also does not vary over the channel length. The power efficiency of such a channel is calculated and the distribution of electric potential is then optimized to yield the maximum efficiency for a given pressure head and flow rate, with a given scalar magnetic potential. Two mathematical theorems are proved for solving the optimization problem, i.e., the problem of minimizing a functional. An upper estimate of the efficiency is made on the basis of a third theorem. An estimate is also made of the flow rate in a conduction channel with a passive electrical system (load without generator). 3 references.

  4. Fisher information as a performance metric for locally optimum processing

    CERN Document Server

    Duan, Fabing; Abbott, Derek

    2011-01-01

    For a known weak signal in additive white noise, the asymptotic performance of a locally optimum processor (LOP) is shown to be given by the Fisher information (FI) of a standardized even probability density function (PDF) of noise in three cases: (i) the maximum signal-to-noise ratio (SNR) gain for a periodic signal; (ii) the optimal asymptotic relative efficiency (ARE) for signal detection; (iii) the best cross-correlation gain (CG) for signal transmission. The minimal FI is unity, corresponding to a Gaussian PDF, whereas the FI is certainly larger than unity for any non-Gaussian PDFs. In the sense of a realizable LOP, it is found that the dichotomous noise PDF possesses an infinite FI for known weak signals perfectly processed by the corresponding LOP. The significance of FI lies in that it provides a upper bound for the performance of locally optimum processing.

  5. Performance-Optimum Superscalar Architecture for Embedded Applications

    CERN Document Server

    Alipour, Mehdi

    2012-01-01

    Embedded applications are widely used in portable devices such as wireless phones, personal digital assistants, laptops, etc. High throughput and real time requirements are especially important in such data-intensive tasks. Therefore, architectures that provide the required performance are the most desirable. On the other hand, processor performance is severely related to the average memory access delay, number of processor registers and also size of the instruction window and superscalar parameters. Therefore, cache, register file and superscalar parameters are the major architectural concerns in designing a superscalar architecture for embedded processors. Although increasing cache and register file size leads to performance improvements in high performance embedded processors, the increased area, power consumption and memory delay are the overheads of these techniques. This paper explores the effect of cache, register file and superscalar parameters on the processor performance to specify the optimum size ...

  6. Characteristics and optimum end uses of alternative energies

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, M.D.

    1980-12-01

    From the perspective of a consulting engineer to public-electric utilities, projections of growth in energy consumption by the year 2000 present both problems and opportunities. Consumption of energy to generate electricity will substantially increase its relative share and alternatives will have to compete with electricity generated from conventional sources in terms of end-use economics. Organizations having a direct interest in furthering coal-fired and nuclear generation have estimated their capabilities to expand. The resulting competition between the conventional technologies and alternative energies will be decided not by the wishes of ''soft path'' proponents but by the outcome of technical and economic feasibility studies. Comparisons are made of five alternative energy options (wind, wood, solar, geothermal and coal conversion) on the basis of four characteristics (schedule, cost, resource, environment). As it turns out, end-use and location may prove to be the overriding considerations.

  7. Maintaining Optimum Pump Performance with Specially- Formulated Hydraulic Fluids

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper describes a battery of tests, and related results, that were performed under normal and severe conditions designed to demonstrate that hydraulic fluids formulated with Lubrizol' s high quality anti - wear hydraulic fluid technology can stand up to today's increasing demands for longer life and provide excellent performance under higher operating temperatures and pressures.

  8. IR image quality assessment and real-time optimum seeking method based on dynamic visual characteristics

    Science.gov (United States)

    Li, Bin; Liu, Gang; Gao, Yongmin; Lei, Hao; Wu, Haiying; Wang, Yu; Rong, Xiaolong

    2016-10-01

    Image quality is an important factor that influences the dynamic target information perception; it is the key factor of real-time target state analysis and judgment. In order to solve the multi-observation station comparison and video optimum seeking problem in the process of target information perception and recognition, an image quality assessment method based on visual characteristics is proposed for infrared target tracking. First, it analyses the basic infrared target image characteristics and application requirements, analyses the status and problems of the multi station optimum seeking technology. According to the expected research results, the processing flow of image processing is established. Then, the image quality objective assessment index is established, which reflects the basic characteristics of the target image, and the assessment index is integrated into the normalized assessment function. According to the quality assessment function, the infrared image quality assessment based on infrared target recognition and image analysis processing is realized, which is mainly characterized by the region of interest and dynamic visual characteristics. And on the basis of this technology, the real-time optimum seeking of multi station infrared target tracking image is completed. In order to verify the effectiveness of the method and the practical application effect, it designs the quality assessment and comparison of different station infrared images. Example shows that the method proposed in this paper can realize multi-observation station infrared image assessment comparison, image quality sorting, the optimum seeking of the infrared image based on the quality assessment. The results accord with the characteristics of infrared target image and dynamic visual characteristics.

  9. Optimum selection of high performance mirror substrates for diamond finishing

    Science.gov (United States)

    Woodard, Kenneth S.; Comstock, Lovell E.; Wamboldt, Leonard; Sutherland, James S.

    2016-05-01

    Due to advances in manufacturing processes, the substrate options for high performance diamond machined mirrors are expanding. Fewer compromises have to be made to achieve the needed weight, stiffness and finish while maintaining reasonable costs. In addition to the traditional mirror materials like aluminum and beryllium, there are some less common materials that can now be included in the trade space that fill the cost and performance continuum between wrought aluminum and beryllium mirrors. Aluminum and beryllium, respectively, had been the low cost/fair performance and very high cost/very high performance bounds for substrate selection. These additional substrates provide multiple near net shape blank options and processes, mostly within these bounds, that can be considered in a mirror cost versus performance trade analysis. This paper will include a summary of some advances in manufacturing processes that provide more substrate options for diamond machined mirrors with some sample performance analysis and data. This is merged with the traditional substrate options to illustrate the now larger mirror substrate trade space. Some benchmark structural analysis is provided to back up a generic mirror design trade study.

  10. Achieving optimum sports performance during Ramadan: some practical recommendations.

    Science.gov (United States)

    Maughan, Ronald J; Zerguini, Yacine; Chalabi, Hakim; Dvorak, Jiri

    2012-01-01

    Muslim athletes should fast from sunrise to sunset each day throughout the 30 days of Ramadan. Most athletes will continue to train throughout Ramadan, and they may also be required to compete at this time, but they will also engage in the religious, cultural, and social activities that Ramadan represents. The available evidence indicates that high-level athletes can maintain performance during Ramadan if physical training, food and fluid intake, and sleep are appropriate and well controlled. Individualized monitoring of athletes may help to prevent fatigue and overtraining and to reduce the risk of consequent illness and injury. The timing and intensity of training may require adjustment to optimize the training response, and training close to or after sunset may have advantages, but this will vary between individual and team sports and between environments that are predominantly Muslim and those that are predominantly non-Muslim. Training late in the day allows nutrition interventions after training to promote adaptations to the training stimulus, to promote recovery, and might help to reduce muscle damage. Sleep deficits have a number of adverse effects on well-being and performance, and athletes should ensure adequate sleep throughout Ramadan. In non-Muslim majority environments, especially in team sports, coaches and athletes should be sensitive to the needs of their team-mates who may be fasting. Event organizers should take account of the needs of Muslim athletes when scheduling the dates and timings of sports competitions.

  11. Optimum performance of explosives in a quasistatic detonation cycle

    Science.gov (United States)

    Baker, Ernest L.; Stiel, Leonard I.

    2017-01-01

    Analyses were conducted on the behavior of explosives in a quasistatic detonation cycle. This type of cycle has been proposed for the determination of the maximum work that can be performed by the explosive. The Jaguar thermochemical equilibrium program enabled the direct analyses of explosive performance at the various steps in the detonation cycle. In all cases the explosive is initially detonated to a point on the Hugoniot curve for the reaction products. The maximum useful work that can be obtained from the explosive is equal to the P-V work on the isentrope for expansion after detonation to atmospheric pressure, minus one-half the square of the particle velocity at the detonation point. This quantity is calculated form the internal energy of the explosive at the initial and final atmospheric temperatures. Cycle efficiencies (net work/ heat added) are also calculated with these procedures. For several explosives including TNT, RDX, and aluminized compositions, maximum work effects were established through the Jaguar calculations for Hugoniot points corresponding to C-J, overdriven, underdriven and constant volume detonations. Detonation to the C-J point is found to result in the maximum net work in all cases.

  12. Predicting optimum vortex tube performance using a simplified CFD model

    Energy Technology Data Exchange (ETDEWEB)

    Karimi-Esfahani, M; Fartaj, A.; Rankin, G.W. [Univ. of Windsor, Dept. of Mechanical, Automotive and Materials Engineering, Windsor, Ontario (Canada)]. E-mail: mki_60@hotmail.com

    2004-07-01

    The Ranque-Hilsch tube is a particular type of vortex tube device. The flow enters the device tangentially near one end and exits from the open ends of the tube. The inlet air is of a uniform temperature throughout while the outputs are of different temperatures. One outlet is hotter and the other is colder than the inlet air. This device has no moving parts and does not require any additional power for its operation other than that supplied to the device to compress the inlet air. It has, however, not been widely used, mainly because of its low efficiency. In this paper, a simplified 2-dimensional computational fluid dynamics model for the flow in the vortex tube is developed using FLUENT. This model makes use of the assumption of axial symmetry throughout the entire flow domain. Compared to a three-dimensional computational solution, the simplified model requires significantly less computational time. This is important because the model is to be used for an optimization study. A user-defined function is generated to implement a modified version of the k-epsilon model to account for turbulence. This model is validated by comparing a particular solution with available experimental data. The variation of cold temperature drop and efficiency of the device with orifice diameter, inlet pressure and cold mass flow ratio qualitatively agree with experimental results. Variation of these performance indices with tube length did not agree with the experiments for small values of tube length. However, it did agree qualitatively for large values. (author)

  13. Optimum Wing Shape Determination of Highly Flexible Morphing Aircraft for Improved Flight Performance

    Science.gov (United States)

    Su, Weihua; Swei, Sean Shan-Min; Zhu, Guoming G.

    2016-01-01

    In this paper, optimum wing bending and torsion deformations are explored for a mission adaptive, highly flexible morphing aircraft. The complete highly flexible aircraft is modeled using a strain-based geometrically nonlinear beam formulation, coupled with unsteady aerodynamics and six-degrees-of-freedom rigid-body motions. Since there are no conventional discrete control surfaces for trimming the flexible aircraft, the design space for searching the optimum wing geometries is enlarged. To achieve high performance flight, the wing geometry is best tailored according to the specific flight mission needs. In this study, the steady level flight and the coordinated turn flight are considered, and the optimum wing deformations with the minimum drag at these flight conditions are searched by utilizing a modal-based optimization procedure, subject to the trim and other constraints. The numerical study verifies the feasibility of the modal-based optimization approach, and shows the resulting optimum wing configuration and its sensitivity under different flight profiles.

  14. Uniform and Non-Uniform Optimum Scalar Quantizers Performances: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Fendy Santoso

    2008-05-01

    Full Text Available The aim of this research is to investigate source coding, the representation of information source output by finite R bits/symbol. The performance of optimum quantisers subject to an entropy constraint has been studied. The definitive work in this area is best summarised by Shannon’s source coding theorem, that is, a source with entropy H can be encoded with arbitrarily small error probability at any rate R (bits/source output as long as R>H. Conversely, If R the error probability will be driven away from zero, independent of the complexity of the encoder and the decoder employed. In this context, the main objective of engineers is however to design the optimum code. Unfortunately, the rate-distortion theorem does not provide the recipe for such a design. The theorem does, however, provide the theoretical limit so that we know how close we are to the optimum. The full understanding of the theorem also helps in setting the direction to achieve such an optimum. In this research, we have investigated the performances of two practical scalar quantisers, i.e., a Lloyd-Max quantiser and the uniformly defined one and also a well-known entropy coding scheme, i.e., Huffman coding against their theoretically attainable optimum performance due to Shannon’s limit R. It has been shown that our uniformly defined quantiser could demonstrate superior performance. The performance improvements, in fact, are more noticeable at higher bit rates.

  15. Optimum Performance-Based Seismic Design Using a Hybrid Optimization Algorithm

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    S. Talatahari

    2014-01-01

    Full Text Available A hybrid optimization method is presented to optimum seismic design of steel frames considering four performance levels. These performance levels are considered to determine the optimum design of structures to reduce the structural cost. A pushover analysis of steel building frameworks subject to equivalent-static earthquake loading is utilized. The algorithm is based on the concepts of the charged system search in which each agent is affected by local and global best positions stored in the charged memory considering the governing laws of electrical physics. Comparison of the results of the hybrid algorithm with those of other metaheuristic algorithms shows the efficiency of the hybrid algorithm.

  16. DESIGNING THE OPTIMUM CONFIGURATIONS OF CIRCULAR AND SPHERICAL PRODUCT SPECIFICATIONS FOR MULTIPLE QUALITY CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    Byung Rae CHO; Michael D. PHILLIPS; Jami KOVACH

    2005-01-01

    As an integral part of tolerance design in the context of design for six sigma, determining optimal product specifications has become the focus of increased activity, as manufacturing industries strive to increase productivity and improve the quality of their products. Although a number of research papers have been reported in the research community, there is room for improvement. Most existing research papers consider determining optimal specification limits for a single quality characteristic. In this paper, we develop the modeling and optimization procedures for optimum circular and spherical configurations by considering multiple quality characteristics. The concepts of multivariate quality loss function and truncated distribution are incorporated. This has never been adequately addressed, nor has been appropriately applied in industry. A numerical example is shown and comparison studies are made.

  17. Analytical performance investigation of parabolic trough solar collector with computed optimum air gap

    Directory of Open Access Journals (Sweden)

    Devander Kumar, Sudhir Kumar

    2015-01-01

    Full Text Available Parabolic trough collectors have a wide range of industrial as well as domestic applications. This study analytically investigates the performance of non-evacuated absorber tube with glass cover of parabolic trough collector (PTC in terms of overall heat loss from the absorber. The impact of different parameters such as diameter of absorber tube, mean temperature of absorber tube, wind velocity, emissivity of absorber and ambient temperature have been studied and find the optimum value of air gap. The optimum value of air gap has been computed considering one-dimensional steady state model, where heat loss due to convection plus radiation is equal to heat loss due to conduction plus radiation from absorber tube to glass cover under steady state. Optimum air gap is found to be approximately 7mm and 8 mm for an absorber tube of diameter in range of 1.2-3.18cm and 4.5-7.62cm, respectively. Corresponding to optimum air gap, minimum overall heat loss has been observed. Overall heat loss increases with increase in absorber temperature, wind velocity and emissivity of absorber, whereas decreases with increase in air temperature for different absorber tube diameters. Absorber tube with diameters in the range of 3.18-4.5cm gives better performance. From the obtained data, correlations have been developed, which can be further utilized for designing the PTC system for getting desired output.

  18. Effect of Thread Level Parallelism on the Performance of Optimum Architecture for Embedded Applications

    CERN Document Server

    Alipour, Mehdi

    2012-01-01

    According to the increasing complexity of network application and internet traffic, network processor as a subset of embedded processors have to process more computation intensive tasks. By scaling down the feature size and emersion of chip multiprocessors (CMP) that are usually multi-thread processors, the performance requirements are somehow guaranteed. As multithread processors are the heir of uni-thread processors and there isn't any general design flow to design a multithread embedded processor, in this paper we perform a comprehensive design space exploration for an optimum uni-thread embedded processor based on the limited area and power budgets. Finally we run multiple threads on this architecture to find out the maximum thread level parallelism (TLP) based on performance per power and area optimum uni-thread architecture.

  19. Optimum condition by mechanical characteristic evaluation in friction stir welding for 5083-O Al alloy

    Institute of Scientific and Technical Information of China (English)

    Min-Su HAN; Seung-Jun LEE; Jae-Cheul PARK; Seok-Cheol KO; Yong-Bin WOO; Seong-Jong KIM

    2009-01-01

    The mechanical characteristics for friction stir welding (FSW) of 5083-O Al alloy were evaluated. The results show that in FSW at 800 r/min and 124 mm/min, a weld defect is observed at the start point. However, the button shape at the end point is good and the stir zone has a soft appearance. At 267 mm/min, a void occurs at the button. A slight weld defect and rough stir zone are seen both at the start and end points at 342 mm/min. Moreover, at the bottom, a tunnel-type void is observed from an early stage to the end point, and at 1 800 r/min, a weld defect can be found from an early stage to the end point. These defects are rough with imperfect joining due to excessive rotation speed and high physical force. Weld fractures relative to rotational and travel speeds are observed at the stir zone. The optimum FSW conditions are a welding speed of 124 mm/min and a rotational speed of 800 r/min.

  20. Model for Determining the Optimum Location for Performance Improvement in Supply-Chain Strategies

    Directory of Open Access Journals (Sweden)

    Ramona Iulia ȚARȚAVULEA (DIEACONESCU

    2015-06-01

    Full Text Available The economic crisis which started in 2007 has caused damaging effects to most international companies. In several EU countries, foreign investments decreased and international companies closed or relocated production and/or distribution centres, due to cost reduction measures. This paper is aiming to demonstrate that applying a performant solution in defining the supply chain strategy can be a low cost process, which can generate positive effects on the sales and revenues. The research objective is to present a concrete solution for redesigning the supply chain, in order to achieve the optimal delivery strategy. The solution implies the use of mathematic methods, for determining the optimum location for placing a central warehouse, in a geographic region. The use of an optimum delivery strategy leads to lower depositing and transport costs, which generates positive effects on sales, by offering more competitive prices on products. The main contribution of the author is the development of a model, used to identify the optimal location for placing a central warehouse.

  1. Optimization of Thermal Performance of Solar radiation for Optimum Geometrical Shape of Box Type Solar Cooker

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    Jatin Shringi

    2016-04-01

    Full Text Available The objective of paper is to carry out the study of optimization of thermal performance of solar radiation for optimum geometrical shape of a box type solar cooker. The study involves fabrication of different geometries for on field evaluation in region. In observation temperature profiles are plotted against equal time intervals and then figure of merit is calculated. In solar cooking heat transfer modes i.e. conduction, convection and radiation plays a dominant role. The solar technologies for cooking are highly useful in developing countries like India which is enriched with sunshine. The results show that trapezoidal shape is better than other geometrical shapes made and the information will likely impact on design of future solar cookers.

  2. A simple delay-line 4-PPM demodulator with near-optimum performance.

    Science.gov (United States)

    Stevens, M L; Boroson, D M

    2012-02-27

    We describe a simple 4-PPM demodulator that uses analog delay lines and simple 1-bit comparators to determine the least-significant bit and most-significant bit of the 4-PPM encoded data without additional digital signal processing. We show that with good optical filtering the comparator-based demodulator can theoretically operate with sensitivity only 0.23 dB from the optimum 4-ary receiver. We describe as an example of this approach the demodulator built for the Lunar Laser Communication Demonstration and show measured performance within 1.1 dB of the expected sensitivity. The technique is extendable to higher-order, and higher-symbol-rate orthogonal modulation formats.

  3. Performance analysis of irreversible quantum Stirling cryogenic refrigeration cycles and their parametric optimum criteria

    Science.gov (United States)

    Lin, Bihong; Chen, Jincan

    2006-08-01

    The influence of both the quantum degeneracy and the finite-rate heat transfer between the working substance and the heat reservoirs on the optimal performance of an irreversible Stirling cryogenic refrigeration cycle using an ideal Fermi or Bose gas as the working substance is investigated, based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases. The inherent regeneration losses of the cycle are analysed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. In particular, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit are discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Stirling refrigeration cycles working with the ideal quantum and classical gases are revealed.

  4. Optimum Performance Enhancing Strategies of the Gas Turbine Based on the Effective Temperatures

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    Ibrahim Thamir K.

    2016-01-01

    Full Text Available Gas turbines (GT have come to play a significant role in distributed energy systems due to its multi-fuel capability, compact size and low environmental impact and reduced cost. Nevertheless, the low electrical efficiency, typically about 30% (LHV, is an important obstruction to the development of the GT plants. New strategies are designed for the GT plant, to increase the overall performance based on the operational modeling and optimization of GT power plants. The enhancing strategies effect on the GT power plant’s performance (with intercooler, two-shaft, reheat and regenerative based on the real power plant of GT. An analysis based on thermodynamics has been carried out on the modifications of the cycle configurations’ enhancements. Then, the results showed the effect of the ambient and turbine inlet temperatures on the performance of the GT plants to select an optimum strategy for the GT. The performance model code to compare the strategies of the GT plants were developed utilizing the MATLAB software. The results show that, the best thermal efficiency occurs in the intercooler-regenerative-reheated GT strategy (IRHGT; it decreased from 51.5 to 48%, when the ambient temperature increased (from 273 to 327K. Furthermore, the thermal efficiency of the GT for the strategies without the regenerative increased (about 3.3%, while thermal efficiency for the strategies with regenerative increased (about 22% with increased of the turbine inlet temperature. The lower thermal efficiency occurs in the IHGT strategy, while the higher thermal efficiency occurs in the IRHGT strategy. However, the power output variation is more significant at a higher value of the turbine inlet temperature. The simulation model gives a consistent result compared with Baiji GT plant. The extensive modeling performed in this study reveals that; the ambient temperature and turbine inlet temperature are strongly influenced on the performance of GT plant.

  5. Performance Analysis of Various DC-DC Converters with Optimum Controllers for PV Applications

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    R. Sankarganesh

    2014-08-01

    Full Text Available Alternative vehicles to Internal Combustion Engines (ICE, for instance the electric vehicle is becoming popular. Electric Vehicles (EV are pollution free and cost effective because the fossil fuel cost increases day by day. These factors make people passion for electric vehicles. Electrical energy demand necessitates charging of electric vehicles using renewable energy. Among the different renewable energy resources, Photovoltaic (PV cells are suitable for EV. The PV output power capacity is still low, so efforts continue to develop the PV converter and its controller, aiming for higher power-extracting efficiency. The PV system requires a proper DC-DC converter with optimum controller to deliver its maximum power. This study analyses the various DC-DC converters such as buck, boost, cuk and modified cuk converters to find the solution for maximum efficiency. In this study in addition to converters, various Maximum Power Point Tracking (MPPT methods, such as Perturb and Observe, Incremental Conductance along with a proposed algorithm called Brain Emotional Learning Based Intelligent Controller (BELBIC has been analyzed. The operation of the BELBIC is based on the emotion processing mechanism in the brain. This intelligent control is stimulated by the limbic system of the mammalian brain. The performance analysis of the converters and MPPT methods are simulated using MATLAB/SIMULINK. Furthermore, experimental results are presented in order to validate the modified cuk converter with proposed BELBIC algorithm.

  6. Performance analysis for optimum transmission and comparison with maximal ratio transmission for MIMO systems with cochannel interference

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    Lin Sheng-Chou

    2011-01-01

    Full Text Available Abstract This article presents the performance analysis of multiple-input/multiple-output (MIMO systems with quadrature amplitude modulation (QAM transmission in the presence of cochannel interference (CCI in nonfading and flat Rayleigh fading environments. The use of optimum transmission (OT and maximum ratio transmission (MRT is considered and compared. In addition to determining precise results for the performance of QAM in the presence of CCI, it is our another aim in this article to examine the validity of the Gaussian interference model in the MRT-based systems. Nyquist pulse shaping and the effects of cross-channel intersymbol interference produced by CCI due to random symbol of the interfering signals are considered in the precise interference model. The error probability for each fading channel is estimated fast and accurately using Gauss quadrature rules which can approximate the probability density function (pdf of the output residual interference. The results of this article indicate that Gaussian interference model may overestimate the effects of interference, particularly, for high-order MRT-based MIMO systems over fading channels. In addition, OT cannot always outperform MRT due to the significant noise enhancement when OT intends to cancel CCI, depending on the combination of the antennas at the transmitter and the receiver, number of interference and the statistical characteristics of the channel.

  7. Performance analysis and parametric optimum criteria of a regeneration Bose-Otto engine

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hao; Du Jianqiang [School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Liu Sanqiu [Department of Physics, Nanchang University, Nanchang 330047 (China)], E-mail: ncu.wh@163.com

    2009-05-15

    A general regenerative model of the Otto engine cycle working with an ideal Bose gas is used to discuss the influence of quantum degeneracy, regeneration and finite rate heat transfer on the performance of the cycle. Based on the model, expressions for some important parameters, such as the power output and efficiency of the Bose-Otto engine cycle, are derived analytically. By means of numerical calculation and illustration, the influence of the compression ratio of the two isochoric processes and the regenerator effectiveness on the performance of the cycle are discussed and evaluated in detail. Moreover, the general optimal performance characteristics of the cycle are revealed. This analysis could provide a general theoretical tool for the optimal design and operation of real power plants.

  8. Performance analysis and parametric optimum criteria of a regeneration Bose-Otto engine

    Science.gov (United States)

    Wang, Hao; Liu, Sanqiu; Du, Jianqiang

    2009-05-01

    A general regenerative model of the Otto engine cycle working with an ideal Bose gas is used to discuss the influence of quantum degeneracy, regeneration and finite rate heat transfer on the performance of the cycle. Based on the model, expressions for some important parameters, such as the power output and efficiency of the Bose-Otto engine cycle, are derived analytically. By means of numerical calculation and illustration, the influence of the compression ratio of the two isochoric processes and the regenerator effectiveness on the performance of the cycle are discussed and evaluated in detail. Moreover, the general optimal performance characteristics of the cycle are revealed. This analysis could provide a general theoretical tool for the optimal design and operation of real power plants.

  9. Optimum differential terms for lateral motion control performance on the vehicle; Yokoundo seigyo seino ni oyobosu hisenkei bibunko no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Miyamori, A. [Japan Consumer Information Center, Tokyo (Japan); Nakaya, H. [Shibaura Institute of Technology, Tokyo (Japan)

    1997-10-01

    As general knowledge, the lateral control performance of vehicle improves as differential terms increases. But subjective rating has its limits of effect. The coefficient of differential terms and saturated steer angle velocity were set up using the experimental vehicle in several steps. Consequently, the optimum range, that subjective and objective rating were compatible, were made clear. 4 refs., 6 figs., 1 tab.

  10. Characteristic thermal constant and dimensionless heating rate. The links to optimum heating rate in GC

    Science.gov (United States)

    Blumberg; Klee

    2000-09-01

    An initial step in the quest of deriving a generalized approach to optimization of a temperature program in gas chromatography is presented. Central to this is the introduction of a dimensionless heating rate, r. As a first step to defining r, a characteristic thermal constant, thetachar, defined as thetachar = -dT/dk at k = 1, where T and k are, respectively, column temperature and solute retention factor, is introduced and evaluated for our own experimental data and for thermodynamic data from the literature. It was determined that, for silicone stationary phases with a phase ratio of 250, thetachar ranged from about 23 degrees C for low molecular weight hydrocarbons such as dimethylpropane to about 45 degrees C for high molecular weight pesticides such as mirex. It was also found that, for a particular solute and a stationary phase type, a 2 orders of magnitude increase in the film thickness caused only about a 2-fold increase in the characteristic thermal constant. Using thetachar as a fundamental temperature unit in GC and void time as a fundamental time unit, a dimensionless heating rate is introduced and its potential utility for the evaluation of the separation-speed tradeoffs in a temperature-programmed GC is demonstrated.

  11. Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells.

    Science.gov (United States)

    Hedley, Gordon J; Ward, Alexander J; Alekseev, Alexander; Howells, Calvyn T; Martins, Emiliano R; Serrano, Luis A; Cooke, Graeme; Ruseckas, Arvydas; Samuel, Ifor D W

    2013-01-01

    The morphology of bulk heterojunction organic photovoltaic cells controls many of the performance characteristics of devices. However, measuring this morphology is challenging because of the small length-scales and low contrast between organic materials. Here we use nanoscale photocurrent mapping, ultrafast fluorescence and exciton diffusion to observe the detailed morphology of a high-performance blend of PTB7:PC71BM. We show that optimized blends consist of elongated fullerene-rich and polymer-rich fibre-like domains, which are 10-50 nm wide and 200-400 nm long. These elongated domains provide a concentration gradient for directional charge diffusion that helps in the extraction of charge pairs with 80% efficiency. In contrast, blends with agglomerated fullerene domains show a much lower efficiency of charge extraction of ~45%, which is attributed to poor electron and hole transport. Our results show that the formation of narrow and elongated domains is desirable for efficient bulk heterojunction solar cells.

  12. Numerical acoustic characteristics and optimum design of the pressure reducing valve

    Science.gov (United States)

    Guo, P. C.; Sun, L. G.; Sun, S. H.; Feng, J. J.; Wu, K. G.; Luo, X. Q.

    2016-11-01

    The pressure reducing valves are widely used in the technological water supplied ways of gravity flow. A credible pressure reducing valve can provide stable cooling water for units with extremely low maintenance cost and labor intensity in a fairly long period of time. In this paper, a three-dimensional numerical simulation of flow field and acoustic characteristics towards a combined type pressure reducing valve was carried out based on ANSYS Fluent and the FW-H equation. The numerical results achieve the regulation of noise generation, transmission and attenuation. It shows that the sound pressure level of monitoring points seem to be higher and large gradient at low frequencies under the same flow velocity, while it presents reverse results with the increment of frequency and maintains a constant valve finally. At the same time, the monitoring points in the vicinity of throttling cone shows higher sound pressure level and upstream noise is lower than downstream's. Aiming at the problem of valve noise, a modified measure to reduce the flow-induced noise was proposed.

  13. Optimum temperature for the growth performance of juvenile orange-spotted grouper ( Epinephelus coioides H.)

    Science.gov (United States)

    Lin, Xiangzhi; Xie, Shouqi; Su, Yongquan; Cui, Yibo

    2008-02-01

    Effects of water temperature (17, 21, 25, 30 and 35°C) and body size (14.75-281.41 g initial body weight) on food consumption, growth, feed conversion, and dry matter content in orange-spotted grouper fed to satiation were investigated. The combined effect of temperature ( T, °C) and body weight ( W, g) on maximum food consumption ( C max, g/day) was described as: ln C max=-7.411+0.828 ln W+0.317 T-0.004 7 T 2, and the optimum feeding temperature was 33.9°C. The combined effect of temperature and body weight on growth ( G) was described as: ln G=-4.461-0.208ln W+0.394 T-0.006 3 T 2. The optimum growth temperature was 31.4°C, whereas overall growth rates were high at 25, 30 and 35 °C. Feed conversion efficiencies ( FCE, %), increasing first and then decreasing with increasing temperature, averaged from 1.8 to 2.1 in terms of dry weight of food fish. The optimum temperature for FCE tended to be lower than that for growth or feeding. Dry matter content increased with both increasing water temperature (17, 25, 30 and 35°C) and body weight, and the combined effect of temperature and body weight on dry matter content ( DM, %) was described as: ln DM=3.232+0.01 4 ln W-0.004 4 T+0.001 2 Tln W.

  14. Optimum temperature for the growth performance of juvenile orange-spotted grouper (Epinephelus coioides H.)

    Institute of Scientific and Technical Information of China (English)

    LIN Xiangzhi; XIE Shouqi; SU Yongquan; CUI Yibo

    2008-01-01

    Effects of water temperature (17,21,25,30 and 35℃) and body size (14.75-281.41 g initial body weight) on food consumption,growth,feed conversion,and dry matter content in orange-spotted grouper fed to satiation were investigated.The combined effect of temperature (T,℃) and body weight (W, g) on maximum food consumption (Cmax,g/day) was described as:InCmax=-7.411+0.828 InW+0.317T-0.004 7T2,and the optimum feeding temperature was 33.9℃.The combined effect of temperature and body weight on growth (G) was described as: InG=-4.461-0.208lnW+0.394T-0.006 3T2.The optimum growth temperature was 31.4℃,whereas overall growth rates were high at 25,30 and 35℃.Feed conversion efficiencies (FCE,%),increasing first and then decreasing with increasing temperature,averaged from 1.8 to 2.1 in terms of dry weight of food fish.The optimum temperature for FCE tended to be lower than that for growth or feeding.Dry matter content increased with both increasing water temperature (17,25,30 and 35℃) and body weight,and the combined effect of temperature and body weight on dry matter content (DM,%) was described as:InDM =3.232+0.01 4 lnW-0.004 4T+0.001 2TlnW.

  15. Performance of quasi-optimum digital FM demodulators for fading channels

    Science.gov (United States)

    Dharamsi, M. T.; Gupta, S. C.

    1975-01-01

    This paper deals with the problem of digital demodulation of FM signals transmitted over Rayleigh and Rician fading channels. The Rayleigh and Rician fading channels are represented by two quadrature multiplicative nonzero mean white Gaussian processes in addition to an additive zero-mean white Gaussian noise. Quasi-optimum digital baseband demodulation algorithms using various nonlinear estimation techniques are derived. The digital demodulator structures are then simulated on a digital computer for an FM system with first order message spectrum for various values of the parameters for Rayleigh and Rician channels.

  16. Performance of a slurry bubble column reactor for Fischer-Tropsch synthesis: Determination of optimum condition

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Kwang-Jae; Kang, Suk-Hwan; Kim, Seung-Moon; Bae, Jong-Wook; Jun, Ki-Won [Advanced Chemical Technology Division, Korea Research Institute of Chemical Technology (KRICT), P.O. Box 107, Yuseong, Daejeon 305-600 (Korea)

    2010-04-15

    The CO conversion and selectivity to C{sub 1}+ and C{sub 11}+ wax products over Co/Al{sub 2}O{sub 3} as well as Ru/Co/Al{sub 2}O{sub 3} Fischer-Tropsch (F-T)catalysts were investigated by varying reaction temperature (210-250 C), system pressure (1.0-3.0 MPa), GHSV (1000-6000 L/kg/h), superficial gas velocity (1.7-13.6 cm/s) and slurry concentration (9.09-26.67 wt.%) in a slurry bubble column reactor (0.05 m diameter x 1.5 m height) to determine the optimum operating conditions. Squalane or paraffin wax was used as initial liquid media. The overall CO conversion increased with increasing reaction temperature, system pressure and catalyst concentration. However, the local maximum CO conversion was exhibited at GHSV of 1500-2000 L/kg/h and superficial gas velocity of 3.4-5.0 cm/s. The CO conversion in the case of Ru/Co/Al{sub 2}O{sub 3} was much higher and stable than that in the case of Co/Al{sub 2}O{sub 3}. The selectivity to C{sub 11}+ wax products increased slightly with increasing GHSV; on the other hand, it decreased with increasing reaction temperature, system pressure, and solid concentration in a slurry bubble column reactor. It could be concluded that the optimum operating conditions based on the yield of hydrocarbons and wax products were; U{sub G} 6.8-10 cm/s, Cs = 15 wt.%, T = 220-230 C, P = 2.0 MPa in a slurry bubble column reactor for F-T synthesis. (author)

  17. Optimum comfort limits determination through the characteristics of asymmetric thermal radiation in a heated floor space, "ondol".

    Science.gov (United States)

    Yoon, Y J; Park, S D; Sohn, J Y

    1992-09-01

    This study was undertaken to evaluate the effects of the asymmetric radiation on thermal comfort, and to suggest the optimum comfort limits in a radiant heating space. The index of V.R.T. (Vector Radiant Temperature) was used to describe the environmental quality of the heated floor space. Optimum comfort limits of this space were suggested through both theoretical and empirical studies. It is recommended to use not only man's sensation of the ambient air but also that of the floor surface for the determination of the optimum comfort limits on the heated floor space such as an "Ondol" in Korea. In the present study the optimum comfort limits were suggested in terms of the V.R.T. The optimum limits obtained were as follows: the vector radiant temperature 11.0 approximately 15.0 K.

  18. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L. Planted under Early and Optimum Sowing Conditions.

    Directory of Open Access Journals (Sweden)

    Muhammad Amir Bakhtavar

    Full Text Available Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET, improved emergence index (EI and final emergence percentage (FEP. Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  19. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L.) Planted under Early and Optimum Sowing Conditions.

    Science.gov (United States)

    Bakhtavar, Muhammad Amir; Afzal, Irfan; Basra, Shahzad Maqsood Ahmed; Ahmad, Azraf-Ul-Haq; Noor, Mehmood Ali

    2015-01-01

    Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE) and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage) and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET), improved emergence index (EI) and final emergence percentage (FEP). Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  20. OPTIMUM PROSESSENTRERING

    Directory of Open Access Journals (Sweden)

    K. Adendorff

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The paper derives an expression for optimum process centreing for a given design specification and spoilage and/or rework costs.

    AFRIKAANSE OPSOMMING: Die problem Van prosessentrering vir n gegewe ontwerpspesifikasie en herwerk- en/of skrootkoste word behandel.

  1. Nickel cadmium battery performance simulation - A means toward optimum design in satellite applications

    Science.gov (United States)

    Clark, K.; Halpert, G.; Timmerman, P.

    1988-01-01

    It is noted that electrochemically based cell models can advance state-of-the-art battery prediction by allowing variations in the parameters that constitute wear-out and predict end-of-life performance. This modeling method is used as the foundation for the simulation of Ni-Cd battery performance. This simulation tool consists of a comprehensive computer model to be developed which would predict the voltage behavior of a battery under mission conditions.

  2. Low-Complexity LDPC Codes with Near-Optimum Performance over the BEC

    CERN Document Server

    Paolini, Enrico; Varrella, Michela; Matuz, Balazs; Chiani, Marco

    2008-01-01

    Recent works showed how low-density parity-check (LDPC) erasure correcting codes, under maximum likelihood (ML) decoding, are capable of tightly approaching the performance of an ideal maximum-distance-separable code on the binary erasure channel. Such result is achievable down to low error rates, even for small and moderate block sizes, while keeping the decoding complexity low, thanks to a class of decoding algorithms which exploits the sparseness of the parity-check matrix to reduce the complexity of Gaussian elimination (GE). In this paper the main concepts underlying ML decoding of LDPC codes are recalled. A performance analysis among various LDPC code classes is then carried out, including a comparison with fixed-rate Raptor codes. The results show that LDPC and Raptor codes provide almost identical performance in terms of decoding failure probability vs. overhead.

  3. Analysis of performance and optimum configuration of two-stage semiconductor thermoelectric module

    Institute of Scientific and Technical Information of China (English)

    Li Kai-Zhen; Liang Rui-Sheng; Wei Zheng-Jun

    2008-01-01

    In this paper, the theoretical analysis and simulating calculation were conducted for a basic two-stage semiconductor thermoelectric module, which contains one thermocouple in the second stage and several thermocouples in the first stage. The study focused on the configuration of the two-stage semiconductor thermoelectric cooler, especially investigating the influences of some parameters, such as the current I1 of the first stage, the area A1 of every thermocouple and the number n of thermocouples in the first stage, on the cooling performance of the module. The obtained results of analysis indicate that changing the current I1 of the first stage, the area A1 of thcrmocouples and the number n of thermocouples in the first stage can improve the cooling performance of the module. These results can be used to optimize the configuration of the two-stage semiconductor thermoelectric module and provide guides for the design and application of thermoelectric cooler.

  4. Performance analysis and parametric optimum criteria of an irreversible Bose-Otto engine

    Science.gov (United States)

    Wang, Hao; Liu, Sanqiu; He, Jizhou

    2009-04-01

    An irreversible cycle model of a Bose-Otto engine is established, in which finite time thermodynamic processes and the irreversibility result from the nonisentropic compression and expansion processes are taken into account. Based on the model, expressions for the power output and efficiency of the Bose-Otto engine are derived. On the basis of the thermodynamic properties of ideal Bose gas, the effects of the irreversibility and the compression ratio of the two isochoric processes on the performance of the Bose-Otto engine are revealed and some important performance parameters are optimized. Furthermore, some optimal operating regions including those for the power output, efficiency, and the temperatures of the cyclic working substance at two important state points are determined and evaluated. Finally, several special cases are discussed in detail.

  5. Numerical design of the diesel particulate filter for optimum thermal performances during regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Jin [Department of Mechanical Engineering, Graduate School of Hanyang University, Seoul, 133-791 (Korea); Jeong, Soo-Jeong [Advanced Power and IT Research Center, Korea Automotive Technology Institute, Chonan, Chungnam 330-912 (Korea); Kim, Woo-Seung [Department of Mechanical Engineering, Hanyang University, Ansan, Gyunggi-do 425-791 (Korea)

    2009-07-15

    A minimization of the maximum diesel particulate filter (DPF) wall temperature and fast light-off during regeneration are targets for a high durability of the DPF and a high efficiency of soot regeneration. A one-channel numerical model has been adopted in order to predict the transient thermal response of the DPF. The effect of the ratio of the length to diameter (L/D), cell density, the amount of soot loading on the temporal thermal response and regeneration characteristics have been numerically investigated under two representative running conditions: city driving mode and high speed mode. The results indicated that the maximum wall temperature of the DPF increased with increasing 'L/D' in 'high speed mode'. On the contrary, the maximum wall temperature decreases with increasing 'L/D' in the range of 'L/D {>=} 0.6' in 'city driving mode'. The maximum temperature decreased with increasing cell density because heat conduction and heat capacity were increased. Before commencing soot regeneration, the maximum allowed soot loading for retaining DPF durability was about 140 g (5.03 kg/m{sup 3}) under 'city driving mode' and about 200 g (7.19 kg/m{sup 3}) under 'high speed mode' in this study. The effect of the amount of soot loading on light-off time was negligible. (author)

  6. Developing countries SMEs innovation characteristics and performance

    DEFF Research Database (Denmark)

    Rezaei, Shahamak; Brambini-Pedersen, Jan Vang; Baklanov, Nikita

    An econometric study analysing developing countries’ SMEs innovation characteristics and their correlation with performance.......An econometric study analysing developing countries’ SMEs innovation characteristics and their correlation with performance....

  7. The Principle of Pooled Calibrations and Outlier Retainment Elucidates Optimum Performance of Ion Chromatography

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Mikolajczak, Maria; Wojtachnio-Zawada, Katarzyna Olga

    A new principle of statistical data treatment is presented. Since the majority of scientists and costumers are interested in determination of the true amount of analyte in real samples, the focus of attention should be directed towards the concept of accuracy rather than precision. By exploiting...... that the principle of pooled calibrations provides a more realistic picture of the analytical performance with the drawback however, that generally higher levels of uncertainties should be accepted, as compared to contemporary literature values. The implications to the science of analytical chemistry in general...

  8. Performance analysis and parametric optimum criteria of a quantum Otto heat engine with heat transfer effects

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hao [Department of Physics, Nanchang University, Nanchang 330031 (China)], E-mail: ncu.wh@163.com; Liu Sanqiu; He Jizhou [Department of Physics, Nanchang University, Nanchang 330031 (China)

    2009-03-15

    The influence of both the quantum degeneracy and the finite rate heat transfer between the working substance and the cylinder wall on the optimal performance of an Otto engine cycle is investigated. Expressions for several important parameters such as the power output and efficiency are derived. By using numerical solutions, the curves of the power output and efficiency varying with the compression ratio of two isochoric processes are presented. It is found that there are optimal values of the compression ratio at which the power output and efficiency attain their maximum. In particular, the optimal performance of the cycle in strong and weak gas degeneracy and the high temperature limit are discussed in detail. The distinctions and connections between the quantum Otto engine and the classical are revealed. Moreover, the maximum power output and efficiency and the corresponding relevant parameters are calculated, and consequently, the optimization criteria of some important parameters such as the power output, efficiency and compression ratio of the working substance are obtained.

  9. Hadoop Distributed File System-Experiment and Analysis for Optimum Performance

    Directory of Open Access Journals (Sweden)

    Dipayan Dev

    2014-09-01

    Full Text Available The size of the data used in today’s enterprises has been growing at exponential rates from last few years. Simultaneously, the need to process and analyze the large volumes of data has also increased. Hadoop is a popular open-source implementation of MapReduce for the analysis of large datasets. To manage and storage resources across the cluster, Hadoop uses a distributed user-level filesystem. This filesystem, HDFS is written in Java and designed to store very large data sets reliably, and to stream those data sets at high bandwidth to user applications .This paper initially deals with the review of HDFS in details. Later on, the paper reports the experimental work of Hadoop with the big data and suggests the various factors on which Hadoop cluster shows an optimal performance. Paper concludes with providing the different real field challenges of Hadoop in recent days.

  10. The principle of pooled calibrations and outlier retainment elucidates optimum performance of ion chromatography

    DEFF Research Database (Denmark)

    Andersen, Jens; Mikolajczak, Maria; Wojtachnio-Zawada, Katarzyna Olga;

    2012-01-01

    A principle with quality assurance of ion chromatography (IC) is presented. Since the majority of scientists and costumers are interested in the determination of the true amount of analyte in real samples, the focus of attention should be directed towards the concept of accuracy rather than...... focussing on precision. By exploiting the principle of pooled calibrations and retainment of all outliers it was possible to obtain full correspondence between calibration uncertainty and repetition uncertainty, which for the first time evidences statistical control in experiments with ion chromatography...... investigations of method validations where it was found that the principle of pooled calibrations provides a more realistic picture of the analytical performance with the drawback, however, that generally higher levels of uncertainties should be accepted, as compared to contemporary literature values...

  11. TRAINING AT THE OPTIMUM POWER ZONE PRODUCES SIMILAR PERFORMANCE IMPROVEMENTS TO TRADITIONAL STRENGTH TRAINING

    Directory of Open Access Journals (Sweden)

    Irineu Loturco

    2013-03-01

    Full Text Available The purpose of this study was to test if substituting a regular maximum strength-oriented training regimen by a power-oriented one at the optimal power load in the first phase of a traditional periodization produces similar performance improvements later on into the training period. Forty five soldiers of the Brazilian brigade of special operations with at least one year of army training experience were divided into a control group (CG - n = 15, 20.18 ± 0.72 yrs, 1.74 ± 0.06 m, 66.7 ± 9.8 kg, and 1RM/weight ratio = 1.14 ± 0.12, a traditional periodization group (TG - n = 15, 20.11 ± 0.7 yrs, 1.72 ± 0.045 m, 63.1 ± 3.6 kg, and 1RM/weight ratio = 1.21 ± 0.16; and a maximum-power group (MPG - n = 15, 20.5 ± 0.6 yrs, 1.73 ± 0.049m, 67.3 ± 9.8 kg, 1RM/weight ratio = 1.20 ± 0.14. Maximum strength (26.2% and 24.6%, CMJ height (30.8% and 39.1% and sprint speed (11.6% and 14.5% increased significantly (p < 0.05 and similarly for the MPG and TG, respectively, from pre- to post-assessments. Our data suggests that a power training regimen may be used in the initial phase of the training cycle without impairing performance later on into the training period.

  12. Absorbing Markov Chain Models to Determine Optimum Process Target Levels in Production Systems with Dual Correlated Quality Characteristics

    Directory of Open Access Journals (Sweden)

    Mohammad Saber Fallah Nezhad

    2012-03-01

    Full Text Available For a manufacturing organization to compete effectively in the global marketplace, cutting costs and improving overall efficiency is essential.  A single-stage production system with two independent quality characteristics and different costs associated with each quality characteristic that falls below a lower specification limit (scrap or above an upper specification limit (rework is presented in this paper. The amount of reworks and scraps are assumed to be depending on the process parameters such as process mean and standard deviation thus the expected total profit is significantly dependent on the process parameters. This paper develops a Markovian decision making model for determining the process means. Sensitivity analyzes is performed to validate, and a numerical example is given to illustrate the proposed model. The results showed that the optimal process means extremely effects on the quality characteristics’ parameters.

  13. Biomass and leaf-level gas exchange characteristics of three African savanna C4 grass species under optimum growth conditions

    NARCIS (Netherlands)

    Mantlana, K.B.; Veenendaal, E.M.; Arneth, A.; Grispen, V.; Bonyongo, C.M.; Heitkönig, I.M.A.; Lloyd, J.

    2009-01-01

    C4 savanna grass species, Digitaria eriantha, Eragrostis lehmanniana and Panicum repens, were grown under optimum growth conditions with the aim of characterizing their above- and below-ground biomass allocation and the response of their gas exchange to changes in light intensity, CO2 concentration

  14. Temperature-related performance of Yb3+:YAG disc lasers and optimum design for diamond cooling

    Institute of Scientific and Technical Information of China (English)

    Cao Ding-Xiang; Yu Hai-Wu; Zheng Wan-Guo; He Shao-Bo; Wang Xiao-Feng

    2006-01-01

    In this paper the temperature-related performances of the Yb3+:YAG disc laser has been investigated based on quasi-three level rate equation model. A compact diamond window cooling scheme also has been demonstrated. In this cooling scheme, laser disc is placed between two thin discs of single crystal synthetic diamond, the heat transfer from Yb3+:YAG to the diamond, in the direction of the optical axis, and then rapidly conducted radically outward through the diamond to the cooling water at the circumference of the diamond/Yb3+ :YAG assembly. Simulation results show that increasing the thickness of the diamond and the overlap-length (between diamond and water) decreases the disc temperature. Therefore a 0.3-0.5 mm thick diamond window with the overlap-length of 1.5-2.0 mm will provide acceptable cost effective cooling, e.g., with a pump intensity of 15 kW/cm2 and repetitive rate of 10 Hz, to keep the maximum temperature of the lasing disc below a reasonable value (310K), the heat exchange coefficient of water should be about 3000 W/m2K.

  15. Performance evaluation and parametric optimum design of a vacuum thermionic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Tianjun; Chen, Xiaohang, E-mail: chenxh@xmu.edu.cn; Chen, Jincan [Fujian Key Laboratory of Semiconductor Materials and Applications and Department of Physics, Xiamen University, Xiamen 361005 (China); Lin, Bihong [College of Information Science and Engineering, Huaqiao University, Xiamen 361021 (China)

    2016-01-18

    A model of the vacuum thermionic solar cell (VTSC) consisting of a solar concentrator, an emitter, and a collector is proposed, in which the various heat losses including the far- and near-field thermal radiation are taken into account. Formula for the overall efficiency of the system is analytically derived. For given values of the ratio of the front surface area of the absorber to that of the emitter and the vacuum gap between the emitter and the collector, the operating temperatures of the emitter and collector are determined by solving the energy balance equations. The maximum efficiency of the VTSC are calculated for given values of the work functions of the emitter and collector materials, and some key parameters such as the net current density of the VTSC, operating temperatures of the emitter and collector, vacuum gap between the emitter and the collector, and area ratio of the absorber to the emitter are optimally determined. Furthermore, the effects of the work functions and the concentration ratio of the solar irradiation on the performance of the VTSC are discussed and several parametric selection criteria are obtained.

  16. Optimum performance investigation of LYSO crystal pixels: A comparison between GATE simulation and experimental data

    CERN Document Server

    Chen, Ze; Chen, Jin-Da; Zhang, Xiu-Ling; Sun, Zhi-Yu; Huang, Wen-Xue; Wang, Jian-Song; Guo, Zhong-Yan; Xiao, Guo-Qing

    2013-01-01

    Monte Carlo simulation plays an important role in the study of time of flight (TOF) positron emission tomography (PET) prototype. As it can incorporate accurate physical modeling of scintillation detection process, from scintillation light generation, the transport of scintillation photos through the crystal(s), to the conversion of these photons into electronic signals. The Geant4 based simulation software GATE can provide a user-friendly simulation platform containing the properties needed. In this work, we developed a dedicated module in GATE simulation tool. Using this module, we simulated the light yield, energy resolution, time resolution of LYSO pixels with the same cross-section ($4\\times4 mm^{2}$) of different lengths: 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, coupled to a PMT. The experiments were performed to validate the GATE simulation results. The results indicate that the best time resolution (484.0$\\pm$67.5 ps) and energy resolution (13.3$\\pm$0.4 %) could be produced by using pixel with length of 5 mm...

  17. Performance of Optimum and Suboptimum Combining Diversity Reception for Binary DPSK over Independent, Nonidentical Rayleigh Fading Channels

    CERN Document Server

    Fu, Hua

    2010-01-01

    This paper is concerned with the error performance analysis of binary differential phase shift keying with differential detection over the nonselective, Rayleigh fading channel with combining diversity reception. Space antenna diversity reception is assumed. The diversity branches are independent, but have nonidentically distributed statistics. The fading process in each branch is assumed to have an arbitrary Doppler spectrum with arbitrary Doppler bandwidth. Both optimum diversity reception and suboptimum diversity reception are considered. Results available previously apply only to the case of first and second-order diversity. Our results are more general in that the order of diversity is arbitrary. Moreover, the bit error probability (BEP) result is obtained in an exact, closed-form expression which shows the behavior of the BEP as an explict function of the one-bit-interval fading correlation coefficient at the matched filter output, the mean signal-to-noise ratio per bit per branch and the order of diver...

  18. Study on Performance of Infectious Waste Sterilizing Set in Kashan Shahid Beheshti Hospital and Determination of its Optimum Operating Condition

    Directory of Open Access Journals (Sweden)

    M Heidari

    2012-03-01

    Full Text Available Background and Objectives; Autoclaving is one of  the methods which sterilizes infectious solid wastes. Since variety of parameters such as temperature, time, and pressure influence autoclave performance, this study was carried out to evaluate the parameters and set optimum condition for the autoclave apparatus  applied in Shahid Beheshti Hospital in Kashan.Materials and Methods: In this descriptive-analytical study, the performance of subjected autoclave was surveyed based on biological index and through setting 144 tests. Variables were packaging type in two groups (open and wrapped, loading type in three groups (light, medium and heavy, and four temperature-time features in fixed pressure equal to 101 kpa. Biological index was ATCC 7953 which contained Stearotermophilus Geobacillus spores. Finally obtained results were analyzed by Chi-Square test.Results: The results of statistical test showed that there isnt any meaningful relation between packaging type of waste, system loading, and efficiency of sterilization(P>0.05,while meaningful relation was found between system performance and variety states of temperature-time feature(P<0.05, illustrating temperature and time effects in fixed pressure on sterilization of solid waste.Conclusion: Based on the results, the best autoclave operational condition for sterilizing infectious solid wastes are: temperature-time equal to 10 min-140°C and 15 min-134°C in fixed pressure of 101 kpa, respectively. It was also revealed that temperature-time condition suggested by manufactory, i.e. 20min-121°C, is not sufficient for complete sterilization of solid waste.

  19. Spatial and temporal characteristics of optimum process noise values of tropospheric parameters for kinematic analysis of Global Navigation Satellite System (GNSS) sites in Japan

    Science.gov (United States)

    Hirata, Yu'ichiro; Ohta, Yusaku

    2016-12-01

    Kinematic analysis of Global Navigation Satellite System (GNSS) data is useful for the extraction of crustal deformation phenomena occurring over short timescales ranging from seconds to 1 day, such as coseismic and postseismic deformation following large earthquakes. However, a fundamental challenge in kinematic GNSS analysis is to separate unknown parameters, such as site coordinate and tropospheric parameters, due to the strong correlation between them. In this study, we assessed the spatial and temporal characteristics of process noise for unknown tropospheric parameters such as zenith wet tropospheric delay and tropospheric gradient by means of kinematic precise point positioning analysis using Kalman filtering across the Japanese nationwide continuous GNSS network. We estimated kinematic site coordinate time series under different process noise combinations of zenith wet tropospheric delay and tropospheric gradient. The spatial distribution of the optimum process noise value for the zenith wet tropospheric parameter with vertical site coordinate time series clearly showed regional characteristics. In comparison with the wet tropospheric parameter, the spatial characteristics of the tropospheric gradient parameter are less well defined within the scale of the GNSS network. The temporal characteristics of the optimum process noise parameters for each site coordinate component at specific sites indicated a clear annual pattern in the tropospheric gradient parameter for the horizontal components. Finally, we assessed the effects on the kinematic GNSS site coordinate time series of optimizing tropospheric parameter process noise. Compared with recommended process noise values from previous studies, the use of estimated "common" optimum process noise values improved the standard deviation of coordinate time series for the majority of stations. These results clearly indicate that the use of appropriate process noise values is important for kinematic GNSS analysis

  20. The Off-Design Performance Simulation of Marine Gas Turbine Based on Optimum Scheduling of Variable Stator Vanes

    Directory of Open Access Journals (Sweden)

    Zhitao Wang

    2017-01-01

    Full Text Available As one of the antisurge techniques, the adjusting scheme of VSV under off-design conditions has a significant impact on the performance of gas turbines. In this paper, the one-dimensional characteristic of the compressor calculation program is embedded into the zero-dimensional overall gas turbine model, which replaces the original compressor characteristic module. Based on the assembling relationship of the actual components of the marine gas turbine, the architecture of the modular model library is designed, and an integrated simulation platform of marine gas turbine is developed by using MATLAB/GUI software. The influence of the first 3 rows of variable stator vanes of the 9-stage axial compressor working alone on the performance of the compressor at different speeds and different angles was analyzed by the HARIKA compressor characteristic calculation program. Taking the economics and stability of the gas turbine as the optimization objective, the optimization of the first three-stage stator vanes regulation schemes under different working conditions was carried out. The steady-state performance parameters under each working condition of gas turbine of power generation with or without variable stator vane mode were calculated. The study results can provide references for the adjusting scheme of VSV under gas turbine off-design conditions operating process.

  1. Investigation on the characteristics of liquid wastes depending on their generation sources and study on optimum treatment method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Guk; Kim, Dong Chan; Shin, Dae Hyun; Son, Seung Geun; Roh, Nam Sun; Woo, Je Kyung [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

    1995-12-01

    The major research contents conducted this year are as follows: (1) environmental regulation with respect to the treatment of the liquid waste in the U.S.A., (2) the present status of the generation and treatment of liquid wastes for large producers(>1,000 ton/year), (3) analysis for heating value element, heavy metal content, halogenated species on collected samples, (4) investigation on estimation method of energy recovery rate from liquid waste, (5) design of a lab. scale reactor which could be capable of conducting thermal decomposition test with small quantity of sample. In this study, present status of liquid waste generation and treatment is investigated, and thermal decomposition characteristics are studied using a lab. scale thermal reactor. The purpose of this research is to divide liquid waste into groups and to present best treatment method for their each group. (author). 24 refs., 21 figs., 23 tabs.

  2. Some Thoughts on the Characteristic Performance Test

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>As an approach to the interpretation of the closest connection doctrine used for years in the European continent for the choice of the law appliable to contractual relations as well as non-contractual ones,the characteristic performance test evolves with the development of international economic and trade activities.Despite criticisms on this approach as embodied in the Rome Convention,the RomeⅠRegulation retains it.This article will focus on the development of the characteristic performance theory and try to explain that this theory,as one of the interpretations and solutions to the closest connection doctrine universally accepted nowadays,has its strengths and weaknesses.

  3. Measurement campaigns for selection of optimum on-ground performance verification approach for large deployable reflector antenna

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Nielsen, Jeppe Majlund; Kim, Oleksiy S.;

    2012-01-01

    This paper describes the measurement campaigns carried out at P-band (435 MHz) for selection of optimum on-ground verification approach for a large deployable reflector antenna (LDA). The feed array of the LDA was measured in several configurations with spherical, cylindrical, and planar near-field...... techniques at near-field facilities in Denmark and in the Netherlands. The measured results for the feed array were then used in calculation of the radiation pattern and gain of the entire LDA. The primary goals for the campaigns were to obtain realistic measurement uncertainty estimates and to investigate...

  4. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  5. On scaling performance operating characteristics - Caveat emptor

    Science.gov (United States)

    Kantowitz, B. H.; Weldon, M.

    1985-01-01

    Problems associated with scaling and normalizing empirical performance operating characteristics (POCs) are examined. Normalization methods proposed by Wickens (1980) and by Mountford and North (1980) are critically evaluated. Computer simulations are used to generate raw-score and normalized POCs. The interpretation of transformed empirical POCs (Wickens, Mountford, and Schreiner, 1981) is shown to contain inconsistencies. The normalization techniques reviewed fail to resolve POC scaling problems. Caution must be exercised when interpreting transformed POCs.

  6. Performance Characteristics of Hero's Turbine Using Hot Water as a Working Fluid

    OpenAIRE

    FUJII, Terushige; OHTA, Jun-ichi; AKAGAWA, Koji; NAKAMURA, Toshi; Asano, Hitoshi

    1992-01-01

    From the viewpoint of energy conservation and the development of new energy resources,it is important to utilize geothermal resources and waste heat from factories. Among energy conversion device,there is a radial outflow reaction turbine,i.e.,Hero's turbine. Performance characteristics of Hero's turbine are analytically and experimentally clarified for flashing expansion of initially subcooled hot water. It is found that: (a)there is an optimum number of revolutions at which maximum tubine e...

  7. Performance Characteristics of an Armature Voltage Controlled D.C. ...

    African Journals Online (AJOL)

    Performance Characteristics of an Armature Voltage Controlled D.C. Motor. ... the performance characteristics of a test motor are obtained by digital computer analysis. ... speed regulation and response characteristics for the d. c. drive system.

  8. Characteristics explaining performance in downhill mountain biking.

    Science.gov (United States)

    Chidley, Joel B; MacGregor, Alexandra L; Martin, Caoimhe; Arthur, Calum A; Macdonald, Jamie H

    2015-03-01

    To identify physiological, psychological, and skill characteristics that explain performance in downhill (DH) mountain-bike racing. Four studies were used to (1) identify factors potentially contributing to DH performance (using an expert focus group), (2) develop and validate a measure of rider skill (using video analysis and expert judge evaluation), (3) evaluate whether physiological, psychological, and skill variables contribute to performance at a DH competition, and (4) test the specific contribution of aerobic capacity to DH performance. STUDY 1 identified aerobic capacity, handgrip endurance, anaerobic power, rider skill, and self-confidence as potentially important for DH. In study 2 the rider-skill measure displayed good interrater reliability. Study 3 found that rider skill and handgrip endurance were significantly related to DH ride time (β=-0.76 and -0.14, respectively; R2=.73), with exploratory analyses suggesting that DH ride time may also be influenced by self-confidence and aerobic capacity. Study 4 confirmed aerobic capacity as an important variable influencing DH performance (for a DH ride, mean oxygen uptake was 49±5 mL·kg(-1)·min(-1), and 90% of the ride was completed above the 1st ventilatory threshold). In order of importance, rider skill, handgrip endurance, self-confidence, and aerobic capacity were identified as variables influencing DH performance. Practically, this study provides a novel assessment of rider skill that could be used by coaches to monitor training and identify talent. Novel intervention targets to enhance DH performance were also identified, including self-confidence and aerobic capacity.

  9. Performance characteristics of pulse tube refrigerators

    Science.gov (United States)

    Huang, B. J.; Tzeng, T. M.

    In the present study experiments were carried out to investigate the performance characteristics of pulse tube refrigerators. It was found that the cool-down time tc during the transient or start-up period is dominated by the time constant of the pulse tube wall τpt and that the dynamics of a basic pulse tube (BPT) refrigerator approaches that of a first-order system. For steady state operation, the cold-end temperature TL was found to vary with τpt, and the cooling load QL increases monotonically with increasing τpt. This indicates that heat pumped by the gas from the cold to the hot end increases with decreasing hpt (i.e. less energy exchange between the gas and wall). The process of heat storage or release of the pulse tube wall is thus shown to have a negative effect on the performance of a BPT refrigerator. It was thus found experimentally that the gas compression/expansion process inside the pulse tube, which is similar to a Brayton cycle but lies between isothermal and adiabatic, can explain the performance of BPT refrigerators. The present experiment also shows that the performance of a pulse tube refrigerator at transient and steady states is mainly dominated by the time constant of the pulse tube wall τpt.

  10. Evaluation of Dewatering Performance and Fractal Characteristics of Alum Sludge.

    Directory of Open Access Journals (Sweden)

    Yongjun Sun

    Full Text Available The dewatering performance and fractal characteristics of alum sludge from a drinking-water treatment plant were investigated in this study. Variations in residual turbidity of supernatant, dry solid content (DS, specific resistance to filtration (SRF, floc size, fractal dimension, and zeta potential were analyzed. Sludge dewatering efficiency was evaluated by measuring both DS and SRF. Results showed that the optimum sludge dewatering efficiency was achieved at 16 mg∙L(-1 flocculant dosage and pH 7. Under these conditions, the maximum DS was 54.6%, and the minimum SRF was 0.61 × 10(10 m∙kg(-1. Floc-size measurements demonstrated that high flocculant dosage significantly improved floc size. Correlation analysis further revealed a strong correlation between fractal dimension and floc size after flocculation. A strong correlation also existed between floc size and zeta potential, and flocculants with a higher cationic degree had a larger correlation coefficient between floc size and zeta potential. In the flocculation process, the main flocculation mechanisms involved adsorption bridging under an acidic condition, and a combination between charge neutralization and adsorption-bridging interaction under neutral and alkaline conditions.

  11. Evaluation of Dewatering Performance and Fractal Characteristics of Alum Sludge.

    Science.gov (United States)

    Sun, Yongjun; Fan, Wei; Zheng, Huaili; Zhang, Yuxin; Li, Fengting; Chen, Wei

    2015-01-01

    The dewatering performance and fractal characteristics of alum sludge from a drinking-water treatment plant were investigated in this study. Variations in residual turbidity of supernatant, dry solid content (DS), specific resistance to filtration (SRF), floc size, fractal dimension, and zeta potential were analyzed. Sludge dewatering efficiency was evaluated by measuring both DS and SRF. Results showed that the optimum sludge dewatering efficiency was achieved at 16 mg∙L(-1) flocculant dosage and pH 7. Under these conditions, the maximum DS was 54.6%, and the minimum SRF was 0.61 × 10(10) m∙kg(-1). Floc-size measurements demonstrated that high flocculant dosage significantly improved floc size. Correlation analysis further revealed a strong correlation between fractal dimension and floc size after flocculation. A strong correlation also existed between floc size and zeta potential, and flocculants with a higher cationic degree had a larger correlation coefficient between floc size and zeta potential. In the flocculation process, the main flocculation mechanisms involved adsorption bridging under an acidic condition, and a combination between charge neutralization and adsorption-bridging interaction under neutral and alkaline conditions.

  12. Investigation of membrane electrode assemblies (MEAs) for efficient and optimum performance of polymer electrolyte membrane (PEM) fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Okafor, A.C.; Mogbo, H.M.C. [Missouri Univ. of Science and Technology, Rolla, MO (United States). Dept. of Mechanical and Aerospace Engineering

    2009-07-01

    The core component of a proton exchange membrane (PEM) fuel cell is the membrane electrode assembly (MEA) which includes an assembled stack of ion exchange membrane reaction catalysts, and the electrodes that converts hydrogen ions into electricity. This study investigated various MEAs in an effort to improve fuel cell performance and durability. First, a literature review of different commercially available and innovative PEM fuel cell MEAs was conducted. The best performing MEAs were then investigated in terms of fuel cell output voltage, operating temperature, thermal and chemical stability, methanol permeability, proton conductivity, and hydrogen crossover. The selected MEAs based on their high output voltage, ability to withstand chemical/radical attacks, overall fuel cell performance, and other excellent physical properties were identified as phosphoric acid-doped polybenzimidazole (PBI/H{sub 3}PO{sub 4}), disulfonated poly(sulfide sulfone)s (SPSSF), and Nafion 212. Finally, in-house designed and manufactured bipolar plates of different materials and flow field configurations are being used to validate these 3 identified MEAs in a single fuel cell and 3 fuel cell stacks.

  13. Board characteristics, governance objectives, and hospital performance

    DEFF Research Database (Denmark)

    Thiel, Andrea; Winter, Vera; Büchner, Vera Antonia

    2017-01-01

    BACKGROUND: There is a growing need for hospital supervisory boards to support hospital management in different areas, including (financial) monitoring, resource provision, stakeholder relationships, and strategic decision-making. Little is currently known about how boards' emphases...... on these various governance objectives contribute to performance. PURPOSE: Using a dominant logics perspective, this article aims to detect the governance logics that hospital boards emphasize, to determine whether there are distinct clusters of hospitals with the same sets of emphases, and to show how cluster...... theory, and stakeholder theory-can be distinguished, and hospitals can be divided into four clusters based on their board's relative emphasis on the classes. Cluster membership is significantly associated with board characteristics. There is also a significant association between cluster membership...

  14. Forecasting gob gas venthole production performances using intelligent computing methods for optimum methane control in longwall coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Karacan, C. Oezgen [National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory, Pittsburgh, PA 15236 (United States)

    2009-09-01

    Gob gas ventholes (GGV) are used to control methane inflows into a longwall operation by capturing it within the overlying fractured strata before it enters the work environment. Thus, it is important to understand the effects of various factors, such as drilling parameters, location of borehole, applied vacuum by exhausters and mining/panel parameters in order to be able to evaluate the performance of GGVs and to predict their effectiveness in controlling methane emissions. However, a practical model for this purpose currently does not exist. In this paper, we analyzed the total gas flow rates and methane percentages from 10 GGVs located on three adjacent panels operated in Pittsburgh coalbed in Southwestern Pennsylvania section of Northern Appalachian basin. The ventholes were drilled from different surface elevations and were located at varying distances from the start-up ends of the panels and from the tailgate entries. Exhauster pressures, casing diameters, location of longwall face and mining rates and production data were also recorded. These data were incorporated into a multilayer-perceptron (MLP) type artificial neural network (ANN) to model venthole production. The results showed that the two-hidden layer model predicted total production and the methane content of the GGVs with more than 90% accuracy. The ANN model was further used to conduct sensitivity analyses about the mean of the input variables to determine the effect of each input variable on the predicted production performance of GGVs. (author)

  15. Optimum performance of the small scale open and direct solar thermal Brayton cycle at various environmental conditions and constraints

    Energy Technology Data Exchange (ETDEWEB)

    Le Roux, W.G.; Bello-Ochende, T.; Meyer, J.P. [Department of Mechanical and Aeronautical Engineering, University of Pretoria, (South Africa)

    2011-07-01

    The energy of the sun can be transformed into mechanical power through the use of concentrated solar power systems. The use of the Brayton cycle with recuperator has significant advantages but also raises issues such as pressure loss and low net power output which are mainly due to irreversibilities of heat transfer and fluid friction. The aim of this study is to optimize the system to generate maximum net power output. Thermodynamic and dynamic trajectory optimizations were performed on a dish concentrator and an off-the-shelf micro-turbine and the effects of wind, solar irradiance and other environmental conditions and constraints on the power output were analyzed. Results showed that the maximum power output is increased when wind decreases and irradiance increases; solar irradiance was found to have a more significant impact than wind. This study highlighted the factors which impact the power generation of concentrated solar power systems so that designers can take them into account.

  16. Design of linear anti-scatter grid geometry with optimum performance for screen-film and digital mammography systems.

    Science.gov (United States)

    Khodajou-Chokami, H; Sohrabpour, M

    2015-08-01

    A detailed 3D Monte Carlo simulation of the grid geometrical parameters in screen-film mammography (SFM) and digital mammography (DM) systems has been performed. A combination of IEC 60627:2013 international standard conditions and other more clinically relevant parameters were used for this simulation. Accuracy of our results has been benchmarked with previously published data and good agreement has been obtained. Calculations in a wide range of linear anti-scatter grid geometries have been carried out. The evaluated parameters for the SFM system were the Bucky factor (BF) and contrast improvement factor (CIF) and for the DM system it was signal difference-to-noise ratio improvement factor (SIF). The CIF parameter was chosen to be nearly the same as the commercial grade, the BF and SIF were significantly improved compared to commercial grids in use today. Our optimized grid parameters for the SFM system were lead strip thickness d = 12 µm, grid ratio r = 5 and strip density N = 65 lines/cm. And for the DM system these parameters were d = 5 µm, r = 3 and N = 100 lines/cm. Both optimized grid sets have thinner d and higher N compared to the commercial grids.

  17. Optimization of Performance and Emission Characteristics of Diesel Engine with Biodiesel Using Grey-Taguchi Method

    Directory of Open Access Journals (Sweden)

    Goutam Pohit

    2013-01-01

    Full Text Available Engine performances and emission characteristics of Karanja oil methyl ester blended with diesel were carried out on a variable compression diesel engine. In order to search for the optimal process response through a limited number of experiment runs, application of Taguchi method in combination with grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a particular combination of input parameters was predicted so as to achieve optimum response characteristics. It was observed that a blend of fifty percent was most suitable for use in a diesel engine without significantly affecting the engine performance and emissions characteristics.

  18. Predicted optimum ambient temperatures for broiler chickens to dissipate metabolic heat do not affect performance or improve breast muscle quality.

    Science.gov (United States)

    Zahoor, I; Mitchell, M A; Hall, S; Beard, P M; Gous, R M; De Koning, D J; Hocking, P M

    2016-01-01

    An experiment was conducted to test the hypothesis that muscle damage in fast-growing broiler chickens is associated with an ambient temperature that does not permit the birds to lose metabolic heat resulting in physiological heat stress and a reduction in meat quality. The experiment was performed in 4 climate chambers and was repeated in 2 trials using a total of 200 male broiler chickens. Two treatments compared the recommended temperature profile and a cool regimen. The cool regimen was defined by a theoretical model that determined the environmental temperature that would enable heat generated by the bird to be lost to the environment. There were no differences in growth rate or feed intake between the two treatments. Breast muscles from birds on the recommended temperature regimen were lighter, less red and more yellow than those from the cool temperature regimen. There were no differences in moisture loss or shear strength but stiffness was greater in breast muscle from birds housed in the cool compared to the recommended regimen. Histopathological changes in the breast muscle were similar in both treatments and were characterised by mild to severe myofibre degeneration and necrosis with regeneration, fibrosis and adipocyte infiltration. There was no difference in plasma creatine kinase activity, a measure of muscle cell damage, between the two treatments consistent with the absence of differences in muscle pathology. It was concluded that breast muscle damage in fast-growing broiler chickens was not the result of an inability to lose metabolic heat at recommended ambient temperatures. The results suggest that muscle cell damage and breast meat quality concerns in modern broiler chickens are related to genetic selection for muscle yields and that genetic selection to address breast muscle integrity in a balanced breeding programme is imperative.

  19. Comparison of the diagnostic performance of microscopic examination with nested polymerase chain reaction for optimum malaria diagnosis in Upper Myanmar.

    Science.gov (United States)

    Kang, Jung-Mi; Cho, Pyo-Yun; Moe, Mya; Lee, Jinyoung; Jun, Hojong; Lee, Hyeong-Woo; Ahn, Seong Kyu; Kim, Tae Im; Pak, Jhang Ho; Myint, Moe Kyaw; Lin, Khin; Kim, Tong-Soo; Na, Byoung-Kuk

    2017-03-16

    Accurate diagnosis of Plasmodium infection is crucial for prompt malaria treatment and surveillance. Microscopic examination has been widely applied as the gold standard for malaria diagnosis in most part of malaria endemic areas, but its diagnostic value has been questioned, particularly in submicroscopic malaria. In this study, the diagnostic performance of microscopic examination and nested polymerase chain reaction (PCR) was evaluated to establish optimal malaria diagnosis method in Myanmar. A total of 1125 blood samples collected from residents in the villages and towns located in Naung Cho, Pyin Oo Lwin, Tha Beik Kyin townships and Mandalay of Upper Myanmar were screened by microscopic examination and species-specific nested PCR method. Among the 1125 blood samples, 261 samples were confirmed to be infected with malaria by microscopic examination. Evaluation of the 1125 samples by species-specific nested PCR analysis revealed that the agreement between microscopic examination and nested PCR was 87.3% (261/299). Nested PCR successfully detected 38 Plasmodium falciparum or Plasmodium vivax infections, which were missed in microscopic examination. Microscopic examinations also either misdiagnosed the infected Plasmodium species, or did not detect mixed infections with different Plasmodium species in 31 cases. The nested PCR method is more reliable than conventional microscopic examination for the diagnosis of malaria infections, and this is particularly true in cases of mixed infections and submicroscopic infections. Given the observed higher sensitivity and specificity of nested PCR, the molecular method holds enormous promise in malaria diagnosis and species differentiation, and can be applied as an effective monitoring tool for malaria surveillance, control and elimination in Myanmar.

  20. Performance Characteristics of Cross-Fin-Tube-Type Heat Exchanger for Air Conditioner

    Science.gov (United States)

    Sasaki, Naoe; Kakiyama, Shiro; Sanuki, Noriyoshi

    The effects of enhanced heat transfer tube with ability to control the heat transfer disturbance by mechanical tube expanding were experimentally investigated on the performance characteristics of air-cooled cross-fin-tube-type heat exchanger for air conditioner. Three kinds of the enhanced heat transfer tube were developed and used in the experiment. The enhanced heat transfer tube was a kind of spirally grooved tube and composed with the fins smaller than those of the conventional spirally grooved tube excepting four fins located in orthogonal position on the tube circumference. The optimum groove number to enhance the performance of heat exchanger was also shown.

  1. Optimum climb and descent trajectories for airline missions

    Science.gov (United States)

    Erzberger, H.

    1981-01-01

    The characteristics of optimum fixed-range trajectories whose structure is constrained to climb, steady cruise, and descent segments are derived by application of optimal control theory. The performance function consists of the sum of fuel and time costs, referred to as direct operating cost (DOC). The state variable is range to go and the independent variable is energy. In this formulation a cruise segment always occurs at the optimum cruise energy for sufficiently large range. At short ranges (400 n. mi. and less), a cruise segment may also occur below the optimum cruise energy. The existence of such a cruise segment depends primarily on the fuel flow vs thrust characteristics and on thrust constraints. If thrust is a free control variable along with airspeed, it is shown that such cruise segments will not generally occur. If thrust is constrained to some maximum value in climb and to some minimum in descent, such cruise segments generally will occur.

  2. Nanotechnological inventions considerably improve performance characteristics

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2014-06-01

    Full Text Available The invention «The method of production of carbon nanomaterial (RU 2509053» can be used as an additive for concretes and polymers which significantly improves their performance characteristics. The method of production of carbon nanomaterial consists of the following stages: preliminary preparation of sphagnous moss when it is refined from foreign admixtures, dried up to 10% humidity and ground, then ground material is exposed to pyrolysis under the temperature 850–950оC for 1–2 hours and cooled up to the environment temperature. After that amorphous carbon obtained in pyrolysis is treated with mechanical activation in the variable planetary mill for 7–10 hours. The invention makes it possible to provide increased outcome of nanotubes with high cleanliness. The invention «The method of production of nanodispersed metal powders and alloys of them (RU 2509626» relates to the powder metallurgy. Powder metal chloride or powder mixture at least of two metal chlorides is treated in the environment of the water steam which is supplied in reaction space at the rate of 50–100 ml/min at the temperature 400–800оC at the presence of absorbent carbon or introducing carbon oxide (II obtained during dissolution of formic acid HCOOH. The invention provides reliable production of nanodispersed metal powders and alloys of them from 3-d metal range: Ni, Co, Cu, Fe, Zn which can be used in powder metallurgy to improve baking process, in chemical industry as the fillers of polymers and reaction catalysts; as additives to anticorrosive covers, etc.

  3. Developing countries SMEs innovation characteristics and performance

    DEFF Research Database (Denmark)

    Rezaei, Shahamak; Brambini-Pedersen, Jan Vang; Baklanov, Nikita

    This paper aims at reducing this research gap by conducting a survey based econometric assessment of Vietnamese SMEs innovation performance and the relationship between specific innovation traits and firm performance.......This paper aims at reducing this research gap by conducting a survey based econometric assessment of Vietnamese SMEs innovation performance and the relationship between specific innovation traits and firm performance....

  4. Haematological characteristics and performance of West African ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-02-18

    Feb 18, 2009 ... The effects of feeding crude petroleum contaminated forage on haematological characteristics and ... rabbits respectively. However, there is a ... vitamin B6 15 mg, vitamin B12 15 mg, vitamin C 10000 mg, folic acid,. 1200 mg ...

  5. Destination Characteristics that Drive Hotel Performance

    DEFF Research Database (Denmark)

    Assaf, A. George; Josiassen, Alexander; Woo, Linda

    2017-01-01

    The increased market saturation and competition in both domestic and international tourism destinations have renewed interest among hotel operators in identifying the key drivers of hotel performance. This paper presents a comprehensive analysis of the determinants of hotel performance...... and their relative importance across multiple tourist destinations. We employ a two-step estimation method to identify key determinants of hotel performance, using a rich sample of international hotels. Our empirical analyses show that the main drivers of hotel performance are the quality of the educational system......, government support, disposable income, and number of international arrivals within a tourism destination. Results indicate that the most important barriers to hotel performance are the competition among accommodation providers, tax rate and fuel price. We argue for the need for hotel providers to develop...

  6. Optimum design of steel structures

    CERN Document Server

    Farkas, József

    2013-01-01

    This book helps designers and manufacturers to select and develop the most suitable and competitive steel structures, which are safe, fit for production and economic. An optimum design system is used to find the best characteristics of structural models, which guarantee the fulfilment of design and fabrication requirements and minimize the cost function. Realistic numerical models are used as main components of industrial steel structures. Chapter 1 containts some experiences with the optimum design of steel structures Chapter 2 treats some newer mathematical optimization methods. Chapter 3 gives formulae for fabrication times and costs. Chapters 4 deals with beams and columns. Summarizes the Eurocode rules for design. Chapter 5 deals with the design of tubular trusses. Chapter 6 gives the design of frame structures and fire-resistant design rules for a frame. In Chapters 7 some minimum cost design problems of stiffened and cellular plates and shells are worked out for cases of different stiffenings and loads...

  7. Performance characteristics of mix oil biodiesel blends with smoke emissions

    Directory of Open Access Journals (Sweden)

    Sanjay Mohite

    2016-08-01

    July 10th 2016; Available online How to Cite This Article: Mohite. S, Kumar, S. &  Maji, S.  (2016 Performance  characteristics of mix oil biodiesel blends with smoke emissions. Int. Journal of Renewable Energy Development, 5(2, 163-170. http://dx.doi.org/10.14710/ijred.5.2.163-170 

  8. The Optimum Design on Sealing Performance of Plasma Generator%等离子体发生器密封性优化设计研究

    Institute of Scientific and Technical Information of China (English)

    刘强; 刘毅; 张玉成; 张江波

    2015-01-01

    针对等离子体发生器在发射药燃烧产生高温高压的环境下出现漏气现象,通过分析其内部结构、等离子体产生及传输过程,提出等离子体发生器密封的改进优化措施,并在密闭爆发器中进行密封性能验证。结果表明:等离子体发生器内部结构及装配工艺优化调整后,等离子体释放过程更加平稳,持续放电时间延长,发射药燃烧过程中压力曲线最大压力处下降过程变化缓慢,从而有效地解决了等离子体发生器的漏气问题。%In order to improve the sealing performance of plasma generator under high temperature and high pressure during the combustion of gun propellant, the optimum design of plasma generator was presented, and the validation closed bomb test was carried out, based on the analysis of interior structure of plasma generator and the process of generation and transmission of plasma. The results show that, through adjusting the interior structure of plasma generator and optimizing the assembly technique, the discharge time of plasma becomes longer, and the discharge process becomes more stable. The peak value of pressure curve declines slowly, and the leakage phenomena of plasma generated is solved effectively.

  9. Data characteristics that determine classifier performance

    CSIR Research Space (South Africa)

    Van der Walt, Christiaan M

    2006-11-01

    Full Text Available classifiers. 10-fold cross-validation is used to evaluate and compare the performance of the classifiers on the different data sets. 3.1. Artificial data generation Multivariate Gaussian distributions are used to generate artificial data sets. We use d...NN) classifier [8], the multi- layer perceptron (MLP) and support vector machines (SVMs) [9]. The NB, DT, kNN, MLP and SVM classifiers are all implementations of the machine learning package Weka [10]. The Gaussian classifier is a Matlab implementation...

  10. Determining optimum age of Holstein dairy calves when adding chopped alfalfa hay to meal starter diets based on measures of growth and performance.

    Science.gov (United States)

    Hosseini, S M; Ghorbani, G R; Rezamand, P; Khorvash, M

    2016-04-01

    The present study was conducted to determine the optimum age of Holstein dairy calves for an effective inclusion of alfalfa hay (AH) in starter feed on performance, apparent digestibility and feeding behavior. A total of 40 Holstein dairy calves (20 female and 20 male) were used in a completely randomized design in which calves were randomly assigned to one of four different dietary treatments including control (CON) calves fed starter feed without any forage and three treatments consisting of the same starter feed plus 15% chopped AH fed when calves were at the 2nd (AH2), 4th (AH4) or 6th (AH6) week of age. Calves were individually housed and bedded with sand that was replaced every other day. Feed and water were available ad libitum throughout the experiment. Calves were fed milk at 10% of birth BW twice daily until d 57. The study concluded when calves were 73 days old. Starter intake was recorded daily and BW was measured weekly. Data were analyzed as a complete randomized design by MIXED procedures of SAS. Results demonstrate that calves receiving AH treatments numerically consumed more starter feed (0.62 v. 0.78, 0.71 and 0.65 kg/day for CON, AH2, AH4 and AH6, respectively) and had greater average daily gain (ADG) compared with CON (0.48 v. 0.57, 0.49 and 0.49 kg/day for CON, AH2, AH4 and AH6), although the significant difference was observed only between AH2 and CON. Among AH treatments, calves in AH2 had better performance than AH6 in several cases including starter intake, ADG. No detectable differences were observed, however, in apparent dry matter, organic matter or CP digestibility among treatments. Ruminal pH and NH3 concentrations, measured on weeks 4, 6, 8 and 10, were lower for calves fed CON compared with other treatments, with ammonia concentrations decreasing over time. Calves in the AH treatments spent more time eating and ruminating compared with CON. Calves fed CON, however, spent more time on laying down compared with other treatments

  11. Influence of Valve's Characteristic on Total Performance of Three Cylinders Internal Combustion Water Pump

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongxin; ZHANG Tiezhu; WANG Weichao

    2009-01-01

    lntenal combustion pump (ICP) is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve's characteristic on ICP's total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate,output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.

  12. Job Characteristics, Work Involvement, and Job Performance of Public Servants

    Science.gov (United States)

    Johari, Johanim; Yahya, Khulida Kirana

    2016-01-01

    Purpose: The primary purpose of this study is to assess the predicting role of job characteristics on job performance. Dimensions in the job characteristics construct are skill variety, task identity, task significance, autonomy and feedback. Further, work involvement is tested as a mediator in the hypothesized link. Design/methodology/approach: A…

  13. The Influence of Top Management Team Characteristics on BPD Performance

    Directory of Open Access Journals (Sweden)

    Joy Elly Tulung

    2015-12-01

    Full Text Available Based on ”upper echelons theory”, this paper investigates the relation between top management team composition and BPD performance. For top management team characteristics, we employ age, level of education, background of education, gender, and functional background, while for measured the BPD performance we employ return on asset (ROA, return on equity (ROE, capital adequacy ratio (CAR, net interest margin (NIM, loan to deposit ratio (LDR, non-performing loan (NPL and operation expenses to operation income (BOPO. The results show that all characteristics have positive significant influences on BPD performance.

  14. Aggregate packing characteristics of good and poor performing asphalt mixes

    CSIR Research Space (South Africa)

    Denneman, E

    2007-07-01

    Full Text Available The aggregate structure of the compacted mix is a determining factor for the performance of Hot-Mix Asphalt (HMA). In this paper, the grading characteristics of good and poor performing HMA mixes are explored using the concepts of the Bailey method...

  15. The Optimum Replacement of Weapon

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao; ZHANG Jin-chun

    2002-01-01

    The theory of LCC (Life Cycle Cost) is applied in this paper. The relation between the economic life of weapon and the optimum replacement is analyzed. The method to define the optimum replacement time of weapon is discussed.

  16. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters.......The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working...... Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough...

  17. Optimum design of B-series marine propellers

    Directory of Open Access Journals (Sweden)

    M.M. Gaafary

    2011-03-01

    Full Text Available The choice of an optimum marine propeller is one of the most important problems in naval architecture. This problem can be handled using the propeller series diagrams or regression polynomials. This paper introduces a procedure to find out the optimum characteristics of B-series marine propellers. The propeller design process is performed as a single objective function subjected to constraints imposed by cavitation, material strength and required propeller thrust. Although optimization software of commercial type can be adopted to solve the problem, the computer program that has been specially developed for this task may be more useful for its flexibility and possibility to be incorporated, as a subroutine, with the complex ship design process.

  18. Transactive memory system links work team characteristics and performance.

    Science.gov (United States)

    Zhang, Zhi-Xue; Hempel, Paul S; Han, Yu-Lan; Tjosvold, Dean

    2007-11-01

    Teamwork and coordination of expertise among team members with different backgrounds are increasingly recognized as important for team effectiveness. Recently, researchers have examined how team members rely on transactive memory system (TMS; D. M. Wegner, 1987) to share their distributed knowledge and expertise. To establish the ecological validity and generality of TMS research findings, this study sampled 104 work teams from a variety of organizational settings in China and examined the relationships between team characteristics, TMS, and team performance. The results suggest that task interdependence, cooperative goal interdependence, and support for innovation are positively related to work teams' TMS and that TMS is related to team performance; moreover, structural equation analysis indicates that TMS mediates the team characteristics-performance links. Findings have implications both for team leaders to manage their work teams effectively and for team members to improve their team performance.

  19. Facebook use, personality characteristics and academic performance: A correlational study

    OpenAIRE

    Sapsani, Georgia; Tselios, Nikolaos

    2017-01-01

    The present paper examines the relationship between the students personality, use of social media and their academic performance and engagement. In specific, the aim of this study is to examine the relationship of students facebook (fb) use and personality characteristics using the Big Five Personality Test with (a) student engagement, (b) time spent preparing for class, (c) time spent in co-curricular activities and (d) academic performance. Results illustrate that fb time was significantly ...

  20. Do the Managerial Characteristics of Schools Influence Their Performance?

    Science.gov (United States)

    Agasisti, Tommaso; Bonomi, Francesca; Sibiano, Piergiacomo

    2012-01-01

    Purpose: The purpose of this paper is to investigate the role of governance and managerial characteristics of schools. More specifically, the aim is to individuate the factors that are associated to higher schools' performances, as measured through student achievement. Design/methodology/approach: The research is conducted by means of a survey in…

  1. Physical performance characteristics of South African male and ...

    African Journals Online (AJOL)

    Physical performance characteristics of South African male and female ... VO2 max (ml.kg.min-1) males = 47.91 (±7.76) versus females = 37.26 (±6.85). ... to achieve the minimum physiological, fitness and strength profiles that enable them to ...

  2. Do the Managerial Characteristics of Schools Influence Their Performance?

    Science.gov (United States)

    Agasisti, Tommaso; Bonomi, Francesca; Sibiano, Piergiacomo

    2012-01-01

    Purpose: The purpose of this paper is to investigate the role of governance and managerial characteristics of schools. More specifically, the aim is to individuate the factors that are associated to higher schools' performances, as measured through student achievement. Design/methodology/approach: The research is conducted by means of a survey in…

  3. Optimum Aeroelastic Characteristics for Composite Supermaneuverable Aircraft.

    Science.gov (United States)

    1986-07-31

    34 Aeromecanique, 1962, pp. 689-698. 4. E.F. Crawley and J. Dugundji , "Frequency Determination and Non-dimension- alization for Composite Cantilever...their Fixing Restraints into Account,)" Aeromecanique, 1962, pp. 689-698. 4. E.F. Crawley and J. Dugundji , "Frequency Determination and Non-dimension...or not this rule applies to lami- nated structures is of concern to modern structures researchers. Crawley and Dugundji (2] as well as Oyibo and

  4. Relations between mental health team characteristics and work role performance.

    Science.gov (United States)

    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.

  5. Performance characteristics of a CO/sub 2/ waveguide laser

    Energy Technology Data Exchange (ETDEWEB)

    Lavigne, P.; Otis, G.; Vincent, D.

    1979-08-01

    A rugged CW CO2 2-mm-diameter laser tube has been developed and its performance analyzed. It has been found that the small-signal gain was optimum when the CO2 partial pressure in a CO2:Xe:He mixture amounted to about 15 torr with the peak value decreasing with the CO2 proportion. Replacement of part of the CO2 by CO resulted in a significant improvement of the laser efficiency. A power extraction of 0.18 W/cm has been achieved at 110 torr with a CO2:CO:Xe:He mixture of 10:20:4:66 in a 9.5-cm-long discharge. There are indications that a better extraction is possible in longer tubes. Use of a grating as one end mirror was sufficient to control the electric field orientation and led to a greater tuning range by limiting the number of oscillating lines. At the present stage, semi-sealed-off operation is possible with a filling period of about 300 hours.

  6. An Optimum Currency Crisis

    Directory of Open Access Journals (Sweden)

    Paolo Pasimeni

    2014-12-01

    Full Text Available This paper presents an ex-post assessment of the current situation of the EMU in light of the conditions prescribed by the theory of Optimum Currency Areas (OCA. The analysis shows that some of those conditions were satisfied at the inception of the EMU, others were missing at the beginning, but improved over time as expected by the endogenous approach to the OCA theory. The common fiscal capacity was the main missing element of the initial construction of the Eurozone, and still is. The common budget is so exiguous that its effectiveness as shock absorption mechanism is negligible. The analysis then shows how some of the concerns raised on the eve of the euro did actually materialize, even if not immediately. First, in its first decade the Eurozone did not experience major turbulences, because growing financial integration was compensating the need for fiscal transfers, channelling the excess of saving from the ‘core’ to the ‘periphery’. Second, the mechanism generated record-high private indebtedness in the ‘periphery’ and exposure of the banks in the ‘core’, making the whole system more fragile as it relied upon financial markets’ stability. Third, once the long-feared shock hit, the mechanism proved weak and non-resilient. The inherent weaknesses of the EMU became evident. Fourth, as it had been foreseen, the cost of the adjustment after the shock fell mainly on labour, with much higher and longer unemployment in the Eurozone than both non-Eurozone EU and the US. Fifth, as the theory suggested, the lack of common mechanisms of adjustment dramatically increased the socio-economic divergences within the EMU. The paper finally presents a simulation for a common budget of the Eurozone, linked to the relative current account positions of the member states.

  7. Computational studies on small wind turbine performance characteristics

    Science.gov (United States)

    Karthikeyan, N.; Suthakar, T.

    2016-10-01

    To optimize the selection of suitable airfoils for small wind turbine applications, computational investigation on aerodynamic characteristics of low Re airfoils MID321a, MID321d, SG6040, SG6041, SG6042 and SG6043 are carried out for the Reynolds number range of (0.5- 2)×105. The BEM method is used to determine the power coefficient of the rotor from the airfoil characteristics; in addition, the blade parameters like chord and twist are also determined. The newly designed MID321a airfoil shows better aerodynamic performance and maximum power coefficient as compared with other investigated airfoils for wider operating ranges.

  8. Multidimensional performance characteristics and standard of performance in talented youth field hockey players : A longitudinal study

    NARCIS (Netherlands)

    Elferink-Gemser, Marije T.; Visscher, Chris; Lemmink, Koen A. P. M.; Mulder, Theo

    2007-01-01

    To identify performance characteristics that could help predict future elite field hockey players, we measured the anthropometric, physiological, technical, tactical, and psychological characteristics of 30 elite and 35 sub-elite youth players at the end of three consecutive seasons. The mean age of

  9. RELATIONSHIPS BETWEEN MUSCLE FATIGUE CHARACTERISTICS AND MARKERS OF ENDURANCE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Martyn G. Morris

    2008-12-01

    Full Text Available The aim of this study was to examine the relationship of a range of in-vivo whole muscle characteristics to determinants of endurance performance. Eleven healthy males completed a cycle ergometer step test to exhaustion for the determination of the lactate threshold, gross mechanical efficiency, peak power and VO2max. On two separate occasions, contractile and fatigue characteristics of the quadriceps femoris were collected using a specially designed isometric strength-testing chair. Muscle fatigue was then assessed by stimulating the muscle for 3 minutes. Force, rate of force development and rates of relaxation were calculated at the beginning and end of the 3 minute protocol and examined for reliability and in relation to lactate threshold, VO2max, gross mechanical efficiency and peak power. Muscle characteristics, rate of force development and relaxation rate were demonstrated to be reliable measures. Force drop off over the 3 minutes (fatigue index was related to lactate threshold (r = -0.72 p < 0.01 but not to VO2max. The rate of force development related to the peak power at the end of the cycle ergometer test (r = -0.75 p < 0.01. Rates of relaxation did not relate to any of the performance markers. We found in-vivo whole muscle characteristics, such as the fatigue index and rate of force development, relate to specific markers of peripheral, but not to central, fitness components. Our investigation suggests that muscle characteristics assessed in this way is reliable and could be feasibly utilised to further our understanding of the peripheral factors underpinning performance

  10. Performance Characteristics of Absorption Hybrid Cycle Introduced Compressor

    Science.gov (United States)

    Iyoki, Shigeki; Kotani, Yuji; Uemura, Tadashi

    In this paper, four kinds of absorption hybrid cycle which introduced the compressor in the absorption cycle were proposed. As basic cycle of absorption refrigerating machine, the following were chosen: two kinds of single-stage absorption refrigerating machine and two kinds of double effect absorption refrigerating machine. As a working medium-absorbent system, NH3-H2O system, C2H5NH2-H2O system and C2H5NH2-H2O-LiBr system were adopted. Using these three kinds of working medium-absorbent system, the performance characteristics of four kinds of absorption hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  11. Combustion and Performance Characteristics of CI Engine Running with Biodiesel

    OpenAIRE

    Tesfa, Belachew; Mishra, Rakesh; Gu, Fengshou; Ball, Andrew

    2013-01-01

    Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. In the present study, experimental investigations were carried out on the effects of biodiesel types, biodiesel fraction and physical properties on the combustion and performance characteristics of a compression ignition (CI) engine. The experimental work was conducted on a four-cylinder, four -stroke, direct injection (DI) and turbocharg...

  12. Key Performance Characteristics of Organic Shrimp Aquaculture in Southwest Bangladesh

    OpenAIRE

    Christian Reinhard Vogl; Brojo Gopal Paul

    2012-01-01

    In Bangladesh, black tiger shrimp (Penaeus monodon; Fabricius, 1798) aquaculture has come to be one of the most important sectors in both the rural and national economies. Likewise, organic shrimp aquaculture has emerged as an alternative farming enterprise for farmers especially in the southwestern districts of Bangladesh. The present study aims to show key performance characteristics of organic shrimp farmers and farming in a prototypical shrimp farming area in Banglade...

  13. A Study of Coaxial Rotor Performance and Flow Field Characteristics

    Science.gov (United States)

    2016-01-22

    A Study of Coaxial Rotor Performance and Flow Field Characteristics Natasha L. Barbely Aerospace Engineer NASA Ames Research Center Moffett Field...The pressure field generated by the two airfoils aided our interpretation of the more complex coaxial rotor system flow field. The pressure fields...velocity (ft/sec) Z vertical distance between rotors (ft) αS pitch angle (deg), negative pitch down κint coaxial rotor induced power interference

  14. Relationships between Isometric Force-Time Characteristics and Dynamic Performance

    Directory of Open Access Journals (Sweden)

    Thomas Dos’Santos

    2017-09-01

    Full Text Available The purpose of this study was to explore the relationships between isometric mid-thigh pull (IMTP force-time characteristics (peak force and time-specific force vales (100–250 ms and dynamic performance and compare dynamic performance between stronger and weaker athletes. Forty-three athletes from different sports (rowing, soccer, bicycle motocross, and hockey performed three trials of the squat jump (SJ, countermovement jump (CMJ, and IMTP, and performed a one repetition maximum power clean (PC. Reactive strength index modified (RSImod was also calculated from the CMJ. Statistically significant large correlations between IMTP force-time characteristics and PC (ρ = 0.569–0.674, p < 0.001, and moderate correlations between IMTP force-time characteristics (excluding force at 100 ms and RSImod (ρ = 0.389–0.449, p = 0.013–0.050 were observed. Only force at 250 ms demonstrated a statistically significant moderate correlation with CMJ height (ρ = 0.346, p = 0.016 and no statistically significant associations were observed between IMTP force-time characteristics and SJ height. Stronger athletes (top 10 demonstrated statistically significantly greater CMJ heights, RSImods, and PCs (p ≤ 0.004, g = 1.32–1.89 compared to weaker (bottom 10 athletes, but no differences in SJ height were observed (p = 0.871, g = 0.06. These findings highlight that the ability to apply rapidly high levels of force in short time intervals is integral for PC, CMJ height, and reactive strength.

  15. Performance characteristics and optimal analysis of a nonlinear diode refrigerator

    Institute of Scientific and Technical Information of China (English)

    Wang Xiu-Mei; He Ji-Zhou; Liang Hong-Ni

    2011-01-01

    This paper establishes a model of a nonlinear diode refrigerator consisting of two diodes switched in the opposite directions and located in two heat reservoirs with different temperatures. Based on the theory of thermal fluctuations, the expressions of the heat flux absorbed from the heat reservoirs are derived. After the heat leak between the two reservoirs is considered, the cooling rate and the coefficient of performance are obtained analytically. The influence of the heat leak and the temperature ratio on the performance characteristics of the refrigerator is analysed in detail.

  16. Transmittance characteristics and tunable sensor performances of plasmonic graphene ribbons

    Science.gov (United States)

    Yan, Xin; Yuan, Lin; Wang, Yueke; Sang, Tian; Yang, Guofeng

    2016-08-01

    We investigate the transmittance characteristics of graphene ribbons numerically. It is found that the transmission dips originate from the transverse and longitudinal resonances of edge graphene plasmon modes, supported by the graphene ribbon resonator. The environmental refractive index changes are detected by measuring the resulting spectral shifts of the resonant transmission dip, so the graphene ribbons can be applied to plasmonic sensor in infrared. Simulation results show that sensing performances for each resonant mode are similar, and figure of merit can be up to 6. Beside, thanks to the tunable permittivity of graphene by bias voltages, the transmittance spectra and sensor performances can be easily tuned.

  17. Performance characteristics in hydrodynamic water cooled thrust bearings

    Directory of Open Access Journals (Sweden)

    Farooq Ahmad Najar

    2016-09-01

    Full Text Available This paper deals with the study of the influence on performance characteristics of a thrust bearing with the introduction of cooling circuit and flow velocity of coolant within the designed thrust bearings is described. New method of cooling circuit configuration is taken into consideration and water has been chosen as a coolant here in the present work. Flow velocity of coolant, ranging from 0.5m/s to 2.0m/s is proposed. The Finite difference based numerical model has been developed in order to notice the effect on the heat transfer on a large hydrodynamic lubrication thrust bearing in-terms of its performance characteristics. In the present work, the solution of Reynolds equation, an energy equation with viscosity variation and Fourier heat conduction equations, applied with appropriate boundary conditions. From the present investigation, it is observed significant amount of heat content is removed from the bearing with the increase of flow velocity of coolant in an embedded cooling duct within the pad. An important parameter among performance characteristics has prevailed a significant increase in hydrodynamic pressure generation which in turn subsequently increases the load carrying capacity which has been never ever documented in the background literature.

  18. Performance and Characteristics of Heat Pump Clothes Drier

    Science.gov (United States)

    Ambarita, H.; Nasution, D. M.; Gunawan, S.; Nasution, A. H.

    2017-03-01

    In this paper, a study of clothes drying using a heat pump drier has been carried out. The objective is to examine the performance and drying characteristics of the heat pump clothes dryer. The result of performances and drying characteristics were compared with waste heat drying system of split-type residential air conditioner (RAC). A drying chamber with volume 1 m3 integrated with heat pump component had been designed and fabricated. The heat pump operated by vapor compression cycle with power input of 800W and refrigerant R22 as a working fluid. The clothes dried made of pure cotton with initial weight varied from 3.00 kg, 5.25 kg, and 6.38 kg, respectively. The results shown that the drying time and drying rate of heat pump drier are faster than waste heat drying system. The average total performance of heat pump clothes drier is 6.56. On the other hand, SMER which is obtained 1.492 kg/kWh. These values are lower than the SMER of waste heat drying system which shown the average value of 2.492 kg/kWh. In the case of drying clothes, waste heat drying of RAC shows a better performance in comparison with heat pump drying system.

  19. Optimum hot water temperature for absorption solar cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R. [Dpto. Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain); Zacarias, A. [ESIME UPA, IPN, Av. de las Granjas 682, Col. Santa Catarina, 02550, D.F. Mexico (Mexico)

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  20. Fluidization and Optimum Backwashing Conditions in Multimedia Filter

    Directory of Open Access Journals (Sweden)

    Rusul Naseer

    2011-11-01

    Full Text Available The aim of this study is to study and evaluate the fluidization and optimum backwashing conditions which include minimum fluidization velocity, expanded bed porosity and energy dissipation under different operation conditions with different media grain size in multimedia filter. Theoretical and experimental study was performed to evaluate the backwashing process of multimedia filter by fluidizing the filter media whereas backwashing Process was carried out by a pilot laboratory filter of multimedia filter column using different characteristics of filters media. A model was built to predict the expanded bed filter and the fluidized porosity. The result showed that proposed model give a good fit with observed data. It is observed that smaller grain sand was needed a lower value of backwash rate then of the higher grain sand to rise the filter media and the fixed porosity 0.51 will expand to the optimum fluidized porosity 0.704 for a bigger value of grain sand while the smaller value of grain diameter 0.5 mm was expanded to the optimum fluidized porosity 0.68. It is also concluded that the effluent turbidity and detachment rate of deposited material decreases with increasing backwashing time and increasing total backwash rate. It is also concluded that the energy dissipation and the velocity gradient have a dominant mechanism of filter cleaning.

  1. Optimum design of cast iron finned radiator

    Institute of Scientific and Technical Information of China (English)

    赵立华; 张泓森; 董重成

    2003-01-01

    The height, thickness and spacing of fins have an impact on the thermal characteristics of a radiator.The calculation of heat output and metal thermal intensity for cast iron finned radiator are given by using heat transfer formula of vertical plate and parallel fins. Each factor having effect on the metal thermal intensity of a radiator is analyzed and the optimum structure parameters of a radiator are given in order to maximize metal thermal intensity.

  2. Performance and emission characteristics of double biodiesel blends with diesel

    Directory of Open Access Journals (Sweden)

    Kuthalingam Arun Balasubramanian

    2013-01-01

    Full Text Available Recent research on biodiesel focused on performance of single biodiesel and its blends with diesel. The present work aims to investigate the possibilities of the application of mixtures of two biodiesel and its blends with diesel as a fuel for diesel engines. The combinations of Pongamia pinnata biodiesel, Mustard oil biodiesel along with diesel (PMD and combinations of Cotton seed biodiesel, Pongamia pinnata biodiesel along with diesel (CPD are taken for the experimental analysis. Experiments are conducted using a single cylinder direct-injection diesel engine with different loads at rated 3000 rpm. The engine characteristics of the two sets of double biodiesel blends are compared. For the maximum load, the value of Specific Fuel consumption and thermal efficiency of CPD-1 blend (10:10:80 is close to the diesel values. CPD blends give better engine characteristics than PMD blends. The blends of CPD are suitable alternative fuel for diesel in stationary/agricultural diesel engines.

  3. COMPARATIVE ANALYSIS OF PERFORMANCE CHARACTERISTICS OF JET VORTEX TYPE SUPERCHAGES

    Directory of Open Access Journals (Sweden)

    A. Rogovyi

    2016-06-01

    Full Text Available On the basis of mathematical modeling there was carried out a comparative analysis of characteristics of jet vortex type superchargers. Dependences of the energy performance of vortex ejector on the geometry parameters and the largest values in terms of efficiency as well as the coefficient of ejection are analyzed. There were built combined characteristics of vortex chamber pumps and vortex ejectors. Vortex chamber pump has advantage pressure in an exit channel over the vortex ejector, consequently there is a more effective power transmission from a working medium, besides the withdrawal of pumping medium in a tangential channel allows to avoid energy losses owing to rotation of a stream in an exit channel.

  4. Characteristics and Performance of Existing Load Disaggregation Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Mayhorn, Ebony T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sullivan, Greg P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butner, Ryan S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hao, He [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-10

    Non-intrusive load monitoring (NILM) or non-intrusive appliance load monitoring (NIALM) is an analytic approach to disaggregate building loads based on a single metering point. This advanced load monitoring and disaggregation technique has the potential to provide an alternative solution to high-priced traditional sub-metering and enable innovative approaches for energy conservation, energy efficiency, and demand response. However, since the inception of the concept in the 1980’s, evaluations of these technologies have focused on reporting performance accuracy without investigating sources of inaccuracies or fully understanding and articulating the meaning of the metrics used to quantify performance. As a result, the market for, as well as, advances in these technologies have been slowly maturing.To improve the market for these NILM technologies, there has to be confidence that the deployment will lead to benefits. In reality, every end-user and application that this technology may enable does not require the highest levels of performance accuracy to produce benefits. Also, there are other important characteristics that need to be considered, which may affect the appeal of NILM products to certain market targets (i.e. residential and commercial building consumers) and the suitability for particular applications. These characteristics include the following: 1) ease of use, the level of expertise/bandwidth required to properly use the product; 2) ease of installation, the level of expertise required to install along with hardware needs that impact product cost; and 3) ability to inform decisions and actions, whether the energy outputs received by end-users (e.g. third party applications, residential users, building operators, etc.) empower decisions and actions to be taken at time frames required for certain applications. Therefore, stakeholders, researchers, and other interested parties should be kept abreast of the evolving capabilities, uses, and characteristics

  5. PERFORMANCE AND EMISSION CHARACTERISTICS OF CI ENGINE FUELLED WITH NON EDIBLE VEGETABLE OIL AND DIESEL BLENDS

    Directory of Open Access Journals (Sweden)

    T. ELANGO

    2011-04-01

    Full Text Available This study investigates performance and emission characteristics of a diesel engine which is fuelled with different blends of jatropha oil and diesel (10–50%. A single cylinder four stroke diesel engine was used for the experiments at various loads and speed of 1500 rpm. An AVL 5 gas analyzer and a smoke meter were used for the measurements of exhaust gas emissions. Engine performance (specific fuel consumption SFC, brake thermal efficiency, and exhaust gas temperature and emissions (HC, CO, CO2, NOx and Smoke Opacity were measured to evaluate and compute the behaviour of the diesel engine running on biodiesel. The results showed that the brake thermal efficiency of diesel is higher at all loads. Among the blends maximum brake thermal efficiency and minimum specific fuel consumption were found for blends upto 20% Jatropha oil. The specific fuel consumption of the blend having 20% Jatropha oil and 80% diesel (B20 was found to be comparable with the conventional diesel. The optimum blend is found to be B20 as the CO2 emissions were lesser than diesel while decrease in brake thermal efficiency is marginal.

  6. Numerical study of effect of pitch angle on performance characteristics of a HAWT

    Directory of Open Access Journals (Sweden)

    Sudhamshu A.R.

    2016-03-01

    Full Text Available Wind energy is one of the clean renewable forms of energy that can handle the existing global fossil fuel crisis. Although it contributes to 2.5% of the global electricity demand, with diminishing fossil fuel sources, it is important that wind energy is harnessed to a greater extent to meet the energy crisis and problem of pollution. The present work involves study of effect of pitch angle on the performance of a horizontal axis wind turbine (HAWT, NREL Phase VI. The wind velocities considered for the study are 7, 15.1 and 25.1 m/s. The simulations are performed using a commercial CFD code Fluent. A frozen rotor model is used for simulation, wherein the governing equations are solved in the moving frame of reference rotating with the rotor speed. The SST k-ω turbulence model has been used. It is seen that the thrust increases with increase in wind velocity, and decreases with increase in pitch angle. For a given wind velocity, there is an optimum pitch angle where the power generated by the turbine is maximum. The observed effect of pitch angle on the power produced has been correlated to the stall characteristics of the airfoil blade.

  7. Influence of Compression Ratio on the Performance and Emission Characteristics of Annona Methyl Ester Operated DI Diesel Engine

    Directory of Open Access Journals (Sweden)

    Senthil Ramalingam

    2014-09-01

    Full Text Available This study aims to find the optimum performance and emission characteristics of single cylinder variable compression ratio (VCR engine with different blends of Annona methyl ester (AME as fuel. The performance parameters such as specific fuel consumption (SFC, brake thermal efficiency (BTE, and emission levels of HC, CO, Smoke, and NOx were compared with the diesel fuel. It is found that, at compression ratio of 17: 1 for A20 blended fuel (20% AME + 80% Diesel shows better performance and lower emission level which is very close to neat diesel fuel. The engine was operated with different values of compression ratio (15, 16, and 17 to find out best possible combination for operating engine with blends of AME. It is also found that the increase of compression ratio increases the BTE and reduces SFC and has lower emission without any engine in design modifications.

  8. PERFORMANCE CHARACTERISTIC MEMS-BASED IMUs FOR UAVs NAVIGATION

    Directory of Open Access Journals (Sweden)

    H. A. Mohamed

    2015-08-01

    Full Text Available Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK, and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS signal outage.

  9. Performance Characteristic Mems-Based IMUs for UAVs Navigation

    Science.gov (United States)

    Mohamed, H. A.; Hansen, J. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, A. B.

    2015-08-01

    Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs) are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS) or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK), and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS) signal outage.

  10. Performance characteristics of CdTe drift ring detector

    Science.gov (United States)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Veeramani, P.; Kazemi, S.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2014-03-01

    CdTe and CdZnTe material is an excellent candidate for the fabrication of high energy X-ray spectroscopic detectors due to their good quantum efficiency and room temperature operation. The main material limitation is associated with the poor charge transport properties of holes. The motivation of this work is to investigate the performance characteristics of a detector fabricated with a drift ring geometry that is insensitive to the transport of holes. The performance of a prototype Ohmic CdTe drift ring detector fabricated by Acrorad with 3 drift rings is reported; measurements include room temperature current voltage characteristics (IV) and spectroscopic performance. The data shows that the energy resolution of the detector is limited by leakage current which is a combination of bulk and surface leakage currents. The energy resolution was studied as a function of incident X-ray position with an X-ray microbeam at the Diamond Light Source. Different ring biasing schemes were investigated and the results show that by increasing the lateral field (i.e. the bias gradient across the rings) the active area, evaluated by the detected count rate, increased significantly.

  11. Anthropometrics, Physical Performance, and Injury Characteristics of Youth American Football

    Science.gov (United States)

    Caswell, Shane V.; Ausborn, Ashley; Diao, Guoqing; Johnson, David C.; Johnson, Timothy S.; Atkins, Rickie; Ambegaonkar, Jatin P.; Cortes, Nelson

    2016-01-01

    Background: Prior research has described the anthropometric and physical performance characteristics of professional, collegiate, and high school American football players. Yet, little research has described these factors in American youth football and their potential relationship with injury. Purpose: To characterize anthropometric and physical performance measures, describe the epidemiology of injury, and examine the association of physical performance measures with injury among children participating within age-based divisions of a large metropolitan American youth football league. Study Design: Case-control study; Level of evidence, 3. Methods: Demographic, anthropometric, and physical performance characteristics and injuries of 819 male children were collected over a 2-year period (2011-2012). Injury data were collected by the league athletic trainer (AT) and coaches. Descriptive analysis of demographic, anthropometric, and physical performance measures (40-yard sprint, pro-agility, push-ups, and vertical jump) were conducted. Incidence rates were computed for all reported injuries; rates were calculated as the number of injuries per 1000 athlete-exposures (AEs). Multinomial logistic regression was used to identify whether the categories of no injury, no-time-loss (NTL) injury, and time-loss (TL) injury were associated with physical performance measures. Results: Of the 819 original participants, 760 (92.8%) completed preseason anthropometric measures (mean ± SD: age, 11.8 ± 1.2 years; height, 157.4 ± 10.7 cm; weight, 48.7 ± 13.3 kg; experience, 2.0 ± 1.8 years); 640 (78.1%) players completed physical performance measures. The mean (±SD) 40-yard sprint and pro-agility measures of the players were 6.5 ± 0.6 and 5.7 ± 0.5 seconds, respectively; the number of push-ups and maximal vertical jump height were 16.5 ± 9.3 repetitions and 42.3 ± 8.4 cm, respectively. Players assigned to different teams within age divisions demonstrated no differences in

  12. An Evaluation of Performance Characteristics of Primary Display Devices.

    Science.gov (United States)

    Ekpo, Ernest U; McEntee, Mark F

    2016-04-01

    The aim of this study was to complete a full evaluation of the new EIZO RX850 liquid crystal display and compare it to two currently used medical displays in Australia (EIZO GS510 and Barco MDCG 5121). The American Association of Physicists in Medicine (AAPM) Task Group 18 Quality Control test pattern was used to assess the performance of three high-resolution primary medical displays: EIZO RX850, EIZO GS510, and Barco MDCG 5121. A Konica Minolta spectroradiometer (CS-2000) was used to assess luminance response, non-uniformity, veiling glare, and color uniformity. Qualitative evaluation of noise was also performed. Seven breast lesions were displayed on each monitor and photographed with a calibrated 5.5-MP Olympus E-1 digital SLR camera. ImageJ software was used to sample pixel information from each lesion and surrounding background to calculate their conspicuity index on each of the displays. All monitor fulfilled all AAPM acceptance criteria. The performance characteristics for EIZO RX850, Barco MDCG 5121, and EIZO GS510 respectively were as follows: maximum luminance (490, 500.5, and 413 cd/m(2)), minimum luminance (0.724, 1.170, and 0.92 cd/m(2)), contrast ratio (675:1, 428:1, 449:1), just-noticeable difference index (635, 622, 609), non-uniformity (20, 5.92, and 8.5 %), veiling glare (GR = 2465.6, 720.4, 1249.8), and color uniformity (Δu'v' = +0.003, +0.002, +0.002). All monitors demonstrated low noise levels. The conspicuity index (χ) of the lesions was slightly higher in the EIZO RX850 display. All medical displays fulfilled AAPM performance criteria, and performance characteristics of EIZO RX850 are equal to or better than those of the Barco MDCG 5121 and EIZO GS510 displays.

  13. Performance characteristic of thermosyphon heat pipe at radiant heat source

    Science.gov (United States)

    Hrabovský, Peter; Papučík, Štefan; Kaduchová, Katarína

    2016-06-01

    This article discusses about device, which is called heat pipe. This device is with heat source with radiant heat source. Heat pipe is device with high efficiency of heat transfer. The heat pipe, which is describe in this article is termosyphon heat pipe. The experiment with termosyphon heat pipe get a result. On the base of result, it will be in future to create mathematical model in Ansys. Thermosyphon heat pipe is made of copper and distilled water is working fluid. The significance of this experiment consists in getting of the heat transfer and performance characteristic. On the basis of measured and calculated data can be constructed the plots.

  14. Numerical Evaluation ofThe Performance ofA Compression Ignition Cng Engine For Heavy DutyTrucksWithAn Optimum Speed PowerTurbine

    Directory of Open Access Journals (Sweden)

    Alberto A. Boretti

    2011-10-01

    Full Text Available The turbocharged direct injection lean burn Diesel engine is the most efficient engine now in production for transport applications. CNG is an alternative fuel with a better carbon to hydrogen ratio therefore permitting reduced carbon dioxide emissions. It is injected in gaseous form for a much cleaner combustion almost cancelling some of the emissions of the Diesel and it permits a much better energy security within Australia. The paper discusses the best options currently available to convert Diesel engine platforms to CNG, with particular emphasis to the use of these CNG engines within Australia where the refuelling network is scarce. This option is determined in the dual fuel operation with a double injector design that couples a second CNG injector to the Diesel injector. This configuration permits the operation Diesel only or Diesel pilot and CNG main depending on the availability of refuelling stations where the vehicle operates. Results of engine performance simulations are performed for a straight six cylinder 13 litres truck engine with a novel power turbine connected to the crankshaft through a constant variable transmission that may be by-passed when non helpful to increase the fuel economy of the vehicle or when damaging the performances of the after treatment system.

  15. Growing Characteristics of Machine-transplanted Rice Seedlings and the Optimum Time for Top-dressing%水稻机插秧栽培的生育特性及最适追肥时间的研究

    Institute of Scientific and Technical Information of China (English)

    舒畅; 唐春江; 汤洪; 杨通洲; 彭念军

    2014-01-01

    In order to study growing characteristics of machine-transplanted rice seedlings and the optimum time for top-dressing, Xiangzaoxian No.45 which is the main rice cultivar in Yiyang city was taken as the material to study the influences of different top-dressing time after transplanting and different culture methods (machine-transplanting, seedling-throwing and traditional transplanting) on growth period, agricultural characteristics and yield of rice. The results showed that in comparison with the seedling-throwing method and the traditional transplanting method, the machine-transplanting method can shorten the growth period by 2~6 d; the plant height was relatively high, and the tillering rate increased by 12.3~23.2 percentage points; the yield increased by 590.4 kg/hm2 and 636.45 kg/hm2, respectively, but the total grain number and the filled grain number reduced by 10 grains/panicle. Moreover, the research indicated that the optimum time for top-dressing is the 8th day after transplanting, and the yield can reach 7 186.35 kg/hm2, which respectively increased by 366.45 kg/hm2 and 722.85 kg/hm2 in comparison with the other time for top-dressing.%为了研究水稻机插秧栽培的生育特性及最适追肥时间,以益阳市主栽水稻品种湘早籼45号为材料,研究了机插秧移栽不同追肥时间,以及机插栽培与抛秧栽培和洗插秧栽培方式对水稻生育期、农艺性状和产量等的影响。结果表明:与抛秧和洗插秧相比,机插秧的生育期缩短了2~6 d;株高较高,水稻分蘖率提高了12.3~23.2个百分点;产量提高了39.36和42.43 kg/667m2,但总粒数和实粒数减少了10粒/穗左右。同时,研究还表明,在机插秧移栽后第8天追肥最为适宜,其产量达479.09 kg/667m2,比其他追肥的时间的产量提高了24.43和48.19 kg/667m2。

  16. Characteristics and Applications of a High Performance, Miniaturized, Infrasound Sensor

    Science.gov (United States)

    Rothman, J. L.; Marriott, D. A.

    2015-12-01

    Infrasound Sensors have been used for many years to monitor a large number of geophysical phenomena and manmade sources. Due to their large size and power consumption these sensors have typically been deployed in fixed arrays, portable arrays have required trucks to transport the sensors and support equipment. A high performance, miniaturized, infrasound microphone has been developed to enable mobile infrasound measurements that would otherwise be impractical. The new device is slightly larger than a hockey puck, weighs 200g, and consumes less than 150mW. The sensitivity is 0.4V/Pa and self noise at 1Hz is less than 0.63μPa²/Hz. The characteristics were verified using a calibrator tracable to the Los Alamos calibration chamber. Field tests have demonstrated the performance is comparable to a Chaparral model 25. Applications include man portable arrays, mobile installations, and UAV based measurements.

  17. Performance and emissions characteristics of a partially insulated gasoline engine

    Energy Technology Data Exchange (ETDEWEB)

    Siew Hwa Chan [School of Mechanical and Production Engineering, Nanyang Technological Univ. (Singapore)

    2001-03-01

    This paper presents the work continued from the previous study on a low heat rejection (LHR) engine. Instead of using a single-property yttria-stabilized zirconia (YSZ) coating to achieve the thermal barrier for the piston crown, a varying-properties functionally graded material (FGM) was used in this study. Extensive experiments were conducted on a 3-cylinder SI Daihatsu engine with all piston crowns coated with a layer of ceramic, which consists of zirconia and yttria with varying compositions along its thickness. Measurements of engine performance, in particular its fuel consumption and emissions characteristics, were made before and after the application of FGM coatings onto the piston crowns. To gain more insight of improved engine performance, in-cylinder pressure measurements were conducted which provide direct comparison of pressure-volume diagrams between baseline and that coated with FGM. (authors)

  18. Optimum Application of Thermal Factors to Artificial Neural Network Models for Improvement of Control Performance in Double Skin-Enveloped Buildings

    Directory of Open Access Journals (Sweden)

    Kyung-Il Chin

    2013-08-01

    Full Text Available This study proposes an artificial neural network (ANN-based thermal control method for buildings with double skin envelopes that has rational relationships between the ANN model input and output. The relationship between the indoor air temperature and surrounding environmental factors was investigated based on field measurement data from an actual building. The results imply that the indoor temperature was not significantly influenced by vertical solar irradiance, but by the outdoor and cavity temperature. Accordingly, a new ANN model developed in this study excluded solar irradiance as an input variable for predicting the future indoor temperature. The structure and learning method of this new ANN model was optimized, followed by the performance tests of a variety of internal and external envelope opening strategies for the heating and cooling seasons. The performance tests revealed that the optimized ANN-based logic yielded better temperature conditions than the non-ANN based logic. This ANN-based logic increased overall comfortable periods and decreased the frequency of overshoots and undershoots out of the thermal comfort range. The ANN model proved that it has the potential to be successfully applied in the temperature control logic for double skin-enveloped buildings. The ANN model, which was proposed in this study, effectively predicted future indoor temperatures for the diverse opening strategies. The ANN-based logic optimally determined the operation of heating and cooling systems as well as opening conditions for the double skin envelopes.

  19. Generalized Performance Characteristics of Refrigeration and Heat Pump Systems

    Directory of Open Access Journals (Sweden)

    Mahmoud Huleihil

    2010-01-01

    Full Text Available A finite-time generic model to describe the behavior of real refrigeration systems is discussed. The model accounts for finite heat transfer rates, heat leaks, and friction as different sources of dissipation. The performance characteristics are cast in terms of cooling rate (r versus coefficient of performance (w. For comparison purposes, various types of refrigeration/heat pump systems are considered: the thermoelectric refrigerator, the reverse Brayton cycle, and the reverse Rankine cycle. Although the dissipation mechanisms are different (e.g., heat leak and Joule heating in the thermoelectric refrigerator, isentropic losses in the reverse Brayton cycle, and limits arising from the equation of state in the reverse Rankine cycle, the r−w characteristic curves have a general loop shape. There are four limiting types of operation: open circuit in which both r and w vanish in the limit of slow operation; short circuit in which again r and w vanish but in the limit of fast operation; maximum r; maximum w. The behavior of the considered systems is explained by means of the proposed model. The derived formulae could be used for a quick estimation of w and the temperatures of the working fluid at the hot and cold sides.

  20. Internal performance characteristics of vectored axisymmetric ejector nozzles

    Science.gov (United States)

    Lamb, Milton

    1993-01-01

    A series of vectoring axisymmetric ejector nozzles were designed and experimentally tested for internal performance and pumping characteristics at NASA-Langley Research Center. These ejector nozzles used convergent-divergent nozzles as the primary nozzles. The model geometric variables investigated were primary nozzle throat area, primary nozzle expansion ratio, effective ejector expansion ratio (ratio of shroud exit area to primary nozzle throat area), ratio of minimum ejector area to primary nozzle throat area, ratio of ejector upper slot height to lower slot height (measured on the vertical centerline), and thrust vector angle. The primary nozzle pressure ratio was varied from 2.0 to 10.0 depending upon primary nozzle throat area. The corrected ejector-to-primary nozzle weight-flow ratio was varied from 0 (no secondary flow) to approximately 0.21 (21 percent of primary weight-flow rate) depending on ejector nozzle configuration. In addition to the internal performance and pumping characteristics, static pressures were obtained on the shroud walls.

  1. Board Characteristics and Firm Performance: Evidence from Indonesia

    Directory of Open Access Journals (Sweden)

    Athalia Ariati Hidayat

    2015-12-01

    Full Text Available This research examines the effect of board characteristics (comprising in different sized proportions: family commissioners, family directors, independent commissioners, ex-government officer commissioners, and board of commissioners size to firm performance. Using fixed-effects data panel regression, this research investigates 293 firms listed on the Indonesian Stock Exchange during 2008-2012. Firm performance is proxied by market measure (Tobin’s Q and accounting measure (ROA. The findings of this research suggest that the proportion of family commissioners and family directors have positive impact only to Tobin’s Q value, while the proportion of independent directors can increase both Tobin’s Q and ROA. On the other hand, this research finds that the proportion of ex-government officers in the board gives no impact to firm performance. This research also finds that the board size has U-shaped non-linear relationship with firm performance as proxied by Tobin’s Q and ROA.

  2. Performance and reliability characteristic of Stirling cryocoolers in China

    Science.gov (United States)

    Liu, X. G.; Wu, Y. N.; He, L.

    2008-03-01

    With extensive application of infrared detective techniques, Stirling cryocoolers, used as an active cooling source, have been developed vigorously in China. An overview of the status and performance for some Stirling cryocoolers having been developed is presented. To analyze the cooler's reliability characteristic, failure analysis has been done, and the four crucial failure modes affecting cooler's long-life running are wear, gaseous contamination, Helium leakage and fatigue. According to each failure mechanism, the measures taken to control or minimize its damage were discussed, and some experiments were designed and carried to quantitatively analyze the relationship between failure and performance in detail. To the wear, an ageing test, which was thermal cycle and for about 500 h, was used to improve the internal frication status and eliminate the defective products. To the gaseous contamination, an accelerated experiment was carried by adding contaminants to the cooler by a 3-way valve to get the relationship between performance degradation and amount of contaminants. The chance of a fatigue related failure is very small now because of the FEM analysis and screening test. Based on charge pressure experiment results, the criteria to judge the sealing procedure was given by the ratio of leak rate to cooler volume.

  3. Performance Characteristics of a Vertical Axis Hydrokinetic Turbine

    Science.gov (United States)

    Bailin, Benjamin; Flack, Karen; Lust, Ethan

    2016-11-01

    Performance characteristics are presented for a vertical axis hydrokinetic turbine designed for use in a riverine environment. The test turbine is a 1:6 scale model of a three-bladed device (9.5 m span, 6.5 m diameter) that has been proposed by the Department of Energy. Experiments are conducted in the large towing tank (116 m long, 7.9 m wide, 5 m deep) at the United States Naval Academy. The large scale facility allows for scale independent results. The turbine is towed beneath a moving carriage at a constant speed in combination with a shaft brake to achieve the desired tip speed ratio (TSR) range. The measured quantities of turbine thrust, torque and RPM result in power and thrust coefficients for a range of TSR. Results will be presented for cases with quiescent flow and flow with mild surface waves, representative of riverine environments.

  4. Distributed utility technology cost, performance, and environmental characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Y; Adelman, S

    1995-06-01

    Distributed Utility (DU) is an emerging concept in which modular generation and storage technologies sited near customer loads in distribution systems and specifically targeted demand-side management programs are used to supplement conventional central station generation plants to meet customer energy service needs. Research has shown that implementation of the DU concept could provide substantial benefits to utilities. This report summarizes the cost, performance, and environmental and siting characteristics of existing and emerging modular generation and storage technologies that are applicable under the DU concept. It is intended to be a practical reference guide for utility planners and engineers seeking information on DU technology options. This work was funded by the Office of Utility Technologies of the US Department of Energy.

  5. Roasted sesame hulls improve broiler performance without affecting carcass characteristics

    Directory of Open Access Journals (Sweden)

    Kamel Z. Mahmoud

    2015-09-01

    Full Text Available An experiment was conducted to evaluate the effect of using graded levels of roasted sesame hulls (RSH on growth performance and meat quality characteristics in broiler chickens. A total of 360 day-old Lohmann chicks were randomly allocated into 24 floor pens and raised over 42 days. One of four dietary treatments was assigned to each group of six pens in a completely randomized fashion. The chicks in the control group were fed a corn-soybean based diet (RSH-0, while the chicks in treatments two, three, and four were fed graded levels of RSH at 4% (RSH-4, 8% (RSH-8, and 12% (RSH-12, respectively. Diets were formulated to meet broiler chicks’ requirements according to the National Research Council for both starter and finisher rations. The results showed that RSH inclusion increased (P<0.05 feed intake and final body weight without adversely affecting the feed conversion ratio. Broiler chicks fed RSH-12 had heavier (P<0.05 breast and leg cuts compared to the control-fed group with no change to their chemical composition. Water holding capacity (WHC, cooking loss (CL, and shear force (SF reported similar results in all dietary groups. The chemical composition of both thigh and breast cuts was not affected by the RSH. After one day of thawing, colour coordinates of breast cuts behaved similarly in all dietary groups. The results of this study suggest that the addition of RSH to broiler diets up to 12% improves their growth performance; nevertheless, carcass characteristics and meat quality showed no alterations compared to the control-fed group.

  6. Organizational Characteristics Associated With Fundraising Performance of Nonprofit Hospitals.

    Science.gov (United States)

    Erwin, Cathleen Owens; Landry, Amy Yarbrough

    2015-01-01

    Fundraising has become increasingly important to nonprofit hospitals as access to capital has grown more difficult and reimbursement for services more complex. This study analyzes the variation in organizational characteristics and fundraising performance among nonprofit acute care hospitals in the United States to identify and measure critical factors related to one key fundraising performance indicator: public support. Results indicate that the presence of an endowment, along with its value, investments in fundraising, and the geographic location of the organization, account for approximately 46% of variance in public support among nonprofit hospitals. The use of a separate foundation for the fundraising operation is not necessarily associated with measures of fundraising success; however, a majority of hospitals do use a foundation, signaling a strategic choice that may be made for numerous reasons. The study results and limitations are discussed and recommendations are made for maximizing the effectiveness of the fundraising enterprise within nonprofit hospitals. Increasing awareness of challenges associated with fundraising success will enhance the strategic management of fundraising operations by hospital executives and board members.

  7. Performance and flow characteristics of MHD seawater thruster

    Energy Technology Data Exchange (ETDEWEB)

    Doss, E.D.

    1990-01-01

    The main goal of the research is to investigate the effects of strong magnetic fields on the electrical and flow fields inside MHD thrusters. The results of this study is important in the assessment of the feasibility of MHD seawater propulsion for the Navy. To accomplish this goal a three-dimensional fluid flow computer model has been developed and applied to study the concept of MHD seawater propulsion. The effects of strong magnetic fields on the current and electric fields inside the MHD thruster and their interaction with the flow fields, particularly those in the boundary layers, have been investigated. The results of the three-dimensional computations indicate that the velocity profiles are flatter over the sidewalls of the thruster walls in comparison to the velocity profiles over the electrode walls. These nonuniformities in the flow fields give rise to nonuniform distribution of the skin friction along the walls of the thrusters, where higher values are predicted over the sidewalls relative to those over the electrode walls. Also, a parametric study has been performed using the three-dimensional MHD flow model to analyze the performance of continuous electrode seawater thrusters under different operating parameters. The effects of these parameters on the fluid flow characteristics, and on the thruster efficiency have been investigated. Those parameters include the magnetic field (10--20 T), thruster diameter, surface roughness, flow velocity, and the electric load factor. The results show also that the thruster performance improves with the strength of the magnetic field and thruster diameter, and the efficiency decreases with the flow velocity and surface roughness.

  8. Performance Characteristics of Small Global-Positioning-System Tracking Collars

    Directory of Open Access Journals (Sweden)

    T. Dennis

    2010-06-01

    Full Text Available Recent technological advances have made possible the development of animal-tracking devices based on the global positioning system (GPS that are much smaller than what were available previously. However, potential limitations in size-dependent technologies and differences in patterns of behavior between small and large animals could mean that miniaturized GPS tracking devices may not function as well as their larger counterparts. Here, we evaluate the performance characteristics of 105-g GPS collars suitable for prolonged use on animals weighing as little as 2.5 kg. We tested 9 collars in stationary trials at a single reference site and in field deployments on common brushtail possums ( Trichosurus vulpecula/ , a semi-arboreal, nocturnal marsupial. We found in both trials that individual collars differed in several measures of positional accuracy and precision, yet overall the small collars compared favorably with published results of larger devices in similar habitats. Differences in operational characteristics between the two trials were mainly in the number and spatial configuration of satellites used to calculate position fixes, resulting in an increase in median location error from 9.8 m in the stationary tests to an estimated 14.7 m in the field trials. Most probably, these effects were due to dissimilarities in microhabitat features and variation in the orientation of GPS antennae which occurred when the possums changed their body posture during movement. The collars evaluated in this study promise to be a valuable tool for the study of the ecology, behavior, and conservation of many small-to-medium sized animals.

  9. Optimum Safety Levels for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    2005-01-01

    Optimum design safety levels for rock and cube armoured rubble mound breakwaters without superstructure are investigated by numerical simulations on the basis of minimization of the total costs over the service life of the structure, taking into account typical uncertainties related to wave stati...

  10. The Optimum Vibration Generator for the Technological Process in Casting Bays

    Directory of Open Access Journals (Sweden)

    Codruţa-Oana Hamat

    2008-01-01

    Full Text Available The performing of some experimental investigations caucering theapplication of vibrations to the technological processes in foundries has required in the first place a vibration generator. By an analysis of the existent generator types it has been established that the optimum generator for these processes is the pneumatic ball-generator. In the work the principle of functioning of this kind of generator is treated and the dimensional and functional characteristics for two realized prototypes are given.

  11. ROBUST OPTIMUM DESIGN OF LAMINATED COMPOSITE PLATES

    Institute of Scientific and Technical Information of China (English)

    WangXiangyang; ChenJianqiao

    2004-01-01

    A last-ply failure (LPF) analysis method for laminated composite plates is incorporated into the finite element code-ANSYS, and a robust optimum design method is presented. The composite structure is analyzed by considering both in-plane and out-of-plane loads. For a lamina,two major failure modes are considered: matrix failure and fiber breakage that axe characterized by the proper strength criteria in the literature. When a lamina has failed, the laminate stiffness is modified to reflect the damage, and stresses in the structure are re-analyzed. This procedure is repeatedly performed until the whole structure fails and thus the ultimate strength is determined.A structural optimization problem is solved with the fiber orientation and the lamina thickness as the design variables and the LPF load as the objective. Finally, the robust optimum design method for laminates is presented and discussed.

  12. Key Performance Characteristics of Organic Shrimp Aquaculture in Southwest Bangladesh

    Directory of Open Access Journals (Sweden)

    Christian Reinhard Vogl

    2012-05-01

    Full Text Available In Bangladesh, black tiger shrimp (Penaeus monodon; Fabricius, 1798 aquaculture has come to be one of the most important sectors in both the rural and national economies. Likewise, organic shrimp aquaculture has emerged as an alternative farming enterprise for farmers especially in the southwestern districts of Bangladesh. The present study aims to show key performance characteristics of organic shrimp farmers and farming in a prototypical shrimp farming area in Bangladesh. Data was collected in 2009 from organic shrimp farmers in the Kaligonj and Shyamnagar sub-districts through questionnaire interviews, transect walks and focus group discussions. The mean productivity of organic shrimp farming in the area is 320 kg ha−1 yr−1 (ranging from 120 to 711 kg ha−1year−1. Organic farmers are more likely to have a higher monthly income and less aquaculture experience. Moreover, suitable landholdings and classified labor distribution have been found to play an important role in the development of organic shrimp aquaculture. The most common assets of organic shrimp aquaculture are high yield, low production cost, available post larvae and high market prices. Small business farmers are likely to earn more income benefits from organic shrimp aquaculture than their larger-scale counterparts. Finally, the paper suggests that more research is needed to stimulate the success of organic shrimp aquaculture.

  13. Design optimum frac jobs using virtual intelligence techniques

    Science.gov (United States)

    Mohaghegh, Shahab; Popa, Andrei; Ameri, Sam

    2000-10-01

    Designing optimal frac jobs is a complex and time-consuming process. It usually involves the use of a two- or three-dimensional computer model. For the computer models to perform as intended, a wealth of input data is required. The input data includes wellbore configuration and reservoir characteristics such as porosity, permeability, stress and thickness profiles of the pay layers as well as the overburden layers. Among other essential information required for the design process is fracturing fluid type and volume, proppant type and volume, injection rate, proppant concentration and frac job schedule. Some of the parameters such as fluid and proppant types have discrete possible choices. Other parameters such as fluid and proppant volume, on the other hand, assume values from within a range of minimum and maximum values. A potential frac design for a particular pay zone is a combination of all of these parameters. Finding the optimum combination is not a trivial process. It usually requires an experienced engineer and a considerable amount of time to tune the parameters in order to achieve desirable outcome. This paper introduces a new methodology that integrates two virtual intelligence techniques, namely, artificial neural networks and genetic algorithms to automate and simplify the optimum frac job design process. This methodology requires little input from the engineer beyond the reservoir characterizations and wellbore configuration. The software tool that has been developed based on this methodology uses the reservoir characteristics and an optimization criteria indicated by the engineer, for example a certain propped frac length, and provides the detail of the optimum frac design that will result in the specified criteria. An ensemble of neural networks is trained to mimic the two- or three-dimensional frac simulator. Once successfully trained, these networks are capable of providing instantaneous results in response to any set of input parameters. These

  14. Atlas Based Kinematic Optimum Design of the Stewart Parallel Manipulator

    Institute of Scientific and Technical Information of China (English)

    SHAO Zhufeng; TANG Xiaoqiang; WANG Liping; SUN Dengfeng

    2015-01-01

    Optimum design is a key approach to make full use of potential advantages of a parallel manipulator. The optimum design of multi-parameter parallel manipulators(more than three design parameters), such as Stewart manipulator, relies on analysis based and algorithm based optimum design methods, which fall to be accurate or intuitive. To solve this problem and achieve both accurate and intuition, atlas based optimum design of a general Stewart parallel manipulator is established, with rational selection of design parameters. Based on the defined spherical usable workspace(SUW), primary kinematic performance indices of the Stewart manipulator, involving workspace and condition number are introduced and analyzed. Then, corresponding performance atlases are drawn with the established non-dimensional design space, and impact of joint distribution angles on the manipulator performance is analyzed and illustrated. At last, an example on atlas based optimum design of the Stewart manipulator is accomplished to illustrate the optimum design process, considering the end-effector posture. Deduced atlases can be flexibly applied to both quantitative and qualitative analysis to get the desired optimal design for the Stewart manipulator with respect to related performance requirements. Besides, the established optimum design method can be further applied to other multi-parameter parallel manipulators.

  15. Presence detection under optimum fusion in an ultrasonic sensor system.

    Science.gov (United States)

    Srinivasan, Sriram; Pandharipande, Ashish

    2012-04-01

    Reliable presence detection is a requirement in energy-efficient occupancy-adaptive indoor lighting systems. A system of multiple ultrasonic sensors is considered for presence detection, and the performance gain from optimum fusion is studied. Two cases are considered wherein an individual sensor determines presence based on (i) local detection by processing echoes at its receiver, and (ii) the optimum Chair-Varshney fusion rule using multiple sensor detection results. The performance gains of using optimum fusion over local detection are characterized under different sensor system configurations and it is shown that improved detection sensitivity is obtained over a larger detection coverage region.

  16. Optimum Multiuser Detector for Multipath Slow Fading Asynchronous CDMA Channels

    Institute of Scientific and Technical Information of China (English)

    WangZhaocheng; YangZhixing; 等

    1995-01-01

    A structure of optimum multiuser detector for asynchronous CDMA in multipath slow fading channels is derived and the significant performance gain over the conventional RAKE receiv-er is shown by simulation.

  17. Optimum reliable operation of water distribution networks by ...

    African Journals Online (AJOL)

    Optimum reliable operation of water distribution networks by minimising energy cost and chlorine dosage. ... In this study, multi-objective optimisation of water distribution network performance in 3 different scenarios was ... Article Metrics.

  18. Performance characteristics of a diesel engine with deccan hemp oil

    Energy Technology Data Exchange (ETDEWEB)

    O.D. Hebbal; K. Vijayakumar Reddy; K. Rajagopal [Poojya Doddappa Appa College of Engineering, Gulbarga (India)

    2006-10-15

    In this present investigation deccan hemp oil, a non-edible vegetable oil is selected for the test on a diesel engine and its suitability as an alternate fuel is examined. The viscosity of deccan hemp oil is reduced first by blending with diesel in 25/75%, 50/50%, 75/25%, 100/0% on volume basis, then analyzed and compared with diesel. Further blends are heated and effect of viscosity on temperature was studied. The performance and emission characteristics of blends are evaluated at variable loads of 0.37, 0.92, 1.48, 2.03, 2.58, 3.13 and 3.68 kW at a constant rated speed of 1500 rpm and results are compared with diesel. The thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC) are well comparable with diesel, and emissions are a little higher for 25% and 50% blends. At rated load, smoke, carbon monoxide (CO), and unburnt hydrocarbon (HC) emissions of 50% blend are higher compared with diesel by 51.74%, 71.42% and 33.3%, respectively. For ascertaining the validity of results obtained, pure deccan hemp oil results are compared with results of jatropha and pongamia oil for similar works available in the literature and were well comparable. From investigation it has been established that, up to 25% of blend of deccan hemp oil without heating and up to 50% blend with preheating can be substituted for diesel engine without any engine modification. 27 refs., 13 figs., 2 tabs.

  19. Anthropometric characteristics and physical performance of colombian elite male wrestlers.

    Science.gov (United States)

    Ramirez-Velez, Robinson; Argothyd, Rodrigo; Meneses-Echavez, Jose Francisco; Beatriz Sanchez-Puccini, Maria; Lopez-Alban, Carlos Alejandro; Cohen, Daniel Dylan

    2014-12-01

    Wrestling was an important part of the ancient Olympic Games and is still one of the most popular events of the modern Olympic Games. Studies indicate that general physiologic profile of successful wrestlers is high anaerobic power and capacity, muscular strength, above average aerobic power, exceptional flexibility, fat free mass, and a mesomorphic somatotype. The objective of the present study was to evaluate anthropometric characteristics and physical performance of elite male wrestlers. The Colombian Wrestling Team was evaluated while in preparation for the Olympic Games (n = 21; age, 27.9 ± 6.7 years). Athletes were tested on anthropometric and fitness parameters: body composition, somatotype distribution according to Heath-Carter, aerobic capacity, vertical jump, and anaerobic power. The evaluations showed a mean body fat percentage of 13.6% ± 3.0% (95% CI, 12.2%-15%), muscle mass of 46.4% ± 2.2% (95% CI, 45.4%-47.4%), Ponderal index of 41.0 ± 1.8 (95% CI, 40.2-41.8), body adiposity index (BAI) 25.1 ± 3.6 (95% CI, 23.5-26.8), and somatotype distribution mesomorphic-ectomorph (5.3-1.6-3.8). Mean aerobic capacity was 45.9 ± 6.6 mL/kg/min (95% CI, 42.8-48.9), vertical jump was 36.4 ± 6.6 cm (95% CI, 11.8-16.6), and anaerobic power was 92.6 ± 19.5 kg/s (95% CI, 83.7-101.5). These results provided a profile of elite wrestlers that could be used as training targets for developing athletes. The results may also provide information for training and tactical planning.

  20. Optimum thickness of Mossbauer absorber

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    If recoilless fraction fa is available, the optimum absorber thickness dopt can be calculated by maximizing the signal to noise ratio or Q factor. In this work,an approach presented is to get experimental Qexp as a function of the thickness, and then fitting Qexp by its theoretical expression gives fa value. At last the dopt value is deduced from a maximum on the fitted curve. In such a way, thicknesses of six specimens with quadrupole or magnetic hyperfine splitting were optimized.

  1. Performance Characteristics of Agricultural Field Machineries In South- East Nigeria

    Directory of Open Access Journals (Sweden)

    Oduma O

    2017-06-01

    Full Text Available The field performances of agricultural field machineries in South -East agricultural zone of Nigeria were assessed, to enable farmers and agriculturists select suitable farm machines/implements based on soil conditions/characteristics for their agricultural activities. The various implements studied include; disc plough, 2-gang tandem disc harrow, ridger, rotovator and 6-row combine seed planter. Three different makes and models of tractors namely: New Holland (model-NH5610SE and capacity-55.9kw, Massey Ferguson (model-MF430E and capacity-55.2kw and Mahindra (model-NH7570E and capacity-55.9kw with 3- point hitch systems and average age of 1.3 years were used to study the field performances of each of the implements, in five different states that made up the study area. The field performances studied include; implements working speed, operation time, depth of cut, effective and theoretical field capacities, field efficiency, fuel consumption rate, implement power requirements, and wheel slippage, under different soil conditions. Results obtained revealed that the disc plough had field efficiency range of 85.74% to 88.55%, effective and theoretical field capacities range of 0.846 to 1.164ha/hr and 0.961 to 1.319ha/hr respectively; and the highest field (ploughing efficiency was obtained in loamy-sandy soil when the plough was operated with the Massey Ferguson tractor. Harrow recorded field efficiency range of 80.17 to 91.38%, effective and theoretical field capacities range of 0.931 to 1.458ha/hr and 1.151 to 1.667 ha/hr respectively; and the highest field (harrowing efficiency was obtained on sandy-clay soil by New Holland tractor. Ridger recorded 83.65 to 88.82% field efficiency, 0.932 to 1.322ha/hr effective capacity and 1.073 to 1.504ha/hr theoretical field capacity; and sandy-clay gave the highest field (ridging efficiency when operated with a New Holland tractor. The rotovator had field efficiency range of 81.10 to 89.81%, effective and

  2. Egg Qualities and Performance Characteristics of Laying Chicken in ...

    African Journals Online (AJOL)

    ... Characteristics of Laying Chicken in Different Intensive Housing Systems. ... initial and final body weights, hen – day production, mortality rate, feed conversion ... although extended battery cage may be adopted to meet some of the welfare ...

  3. Investigation on the Optimum Performance and Parametric Design of a Variety of Energy Conversion Systems%多种能量转换系统的性能优化与参数设计的研究

    Institute of Scientific and Technical Information of China (English)

    林国星; 陈金灿

    2011-01-01

    Saving energy, increasing efficiency of energy utilization and empoldering new and renewable clean energy sources are emphases of developing energy source in the coming years. The performance optimization and parametric design of energy conversion systems is one of the key science problems in energy utilization with high efficiency. In the present paper, some important research results involving the optimum performance and parametric design of a variety of energy conversion systems, such as the magnetic refrigeration, semiconductor thermoelectric devices, thermal utilization of solar energy , chemical engines and chemical pumps , fuel cell hybrid systems , water electrolysis systems for hydrogen production, Brownian motors , quantum thermodynamic cycle systems , and so on,are introduced in combination with both the research status at home and abroad and the research work of our group in recent years.%节能、提高能效、开发新能源(包括可再生清洁能源)是今后能源发展的重点,而能量转换系统的性能优化与参数设计是高效利用能源的一个关键科学问题.结合国内外的研究现状和本研究组近年来的研究工作,介绍在磁制冷、半导体热电器件、太阳能热利用、化学机与化学泵、燃料电池及其耦合系统、电解水制氢系统、布朗马达及量子热力学循环等能量转换系统的性能优化与参数设计方面所取得的一些重要成果.

  4. Optimum Staging with Varying Thrust Attitude Angle

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1966-07-01

    Full Text Available Optimum staging programme for step rockets of arbitrary number of stages having different specific impulses and mass fractions with stages is derived, the optimization criterion being minimum take-off weight for a desired burntout velocity at an assigned altitude. Variation of thrust attitude angle from stage to stage and effects of gravity factor are taken into account. Analysis is performed for a degenerate problem obtained by relaxing the altitude constraint and it has been shown that problems of Weisbord, Subotowicz, Hall & Zambelli and Malina & Summerfield are the particular cases of the degenerate problem.

  5. Rail gun performance and plasma characteristics due to wall ablation

    Science.gov (United States)

    Ray, P. K.

    1986-01-01

    The experiment of Bauer, et al. (1982) is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time.

  6. Effects of College Programme Characteristics on Graduates' Performance

    Science.gov (United States)

    García-Aracil, Adela

    2015-01-01

    Education programmes are designed to equip young populations with the qualifications required to assume responsible roles in specific professions and in society generally. In this paper, the focus of the analysis is on the significance of a number of higher education programme characteristics in allocating young higher education graduates across…

  7. Performance of sampling methods to estimate log characteristics for wildlife.

    Science.gov (United States)

    Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton

    2004-01-01

    Accurate estimation of the characteristics of log resources, or coarse woody debris (CWD), is critical to effective management of wildlife and other forest resources. Despite the importance of logs as wildlife habitat, methods for sampling logs have traditionally focused on silvicultural and fire applications. These applications have emphasized estimates of log volume...

  8. Performance and antrhropometric characteristics of Elite Rugby Players.

    Science.gov (United States)

    Pasin, Federico; Caroli, Barbara; Spigoni, Valentina; Dei Cas, Alessandra; Volpi, Riccardo; Galli, Carlo; Passeri, Giovanni

    2017-08-23

    Physical performance is the result of a complex combination of several factors such as genetic and anthropometric aspects, nutrition and hormonal status. In the past few years many studies have considered the impact of vitamin D on muscular strength and athletic performance.The aim of the present study was to assess the anthropometric measures impacting on physical performance in a group of professional rugby athletes.  As a secondary aim we investigated a possible relationship between baseline vitamin D status and athletic performance status in these subjects. All rugby players completed a test-retest reliability study on performance measures, as 70kg jump squat and body weight (BW) jump squat to assess musculoskeletal performance. Additionally at the time point we collected a blood sample of every athletes for the assessment of serum vitamin D. We found that lean mass was an important independent predictor of performance score in 70kg jump squat (p=0.007, R2=0.74) and BW jump squat (p=0.010, R2=0.66) in these well trained athletes. No statistically significant association was present between performance score and serum vitamin D in this specific setting. We demonstrate a positive interaction between lower limb lean mass and performance score, but we have not been able to identify any statistically significant association between worsening in performance measures and decrease of serum 25 OH Vitamin D.

  9. 空气源电化学连续分离制氧(Ⅰ):单池性能优化%Electrochemical continuous separation of oxygen from air (Ⅰ): Optimum of single cell performances

    Institute of Scientific and Technical Information of China (English)

    朱晓兵; 张建辉; 李小松; 刘景林; 刘剑豪; 金灿

    2016-01-01

    With rapid development of industrial processes, in particular more recently influenced by "Haze", air quality draws more and more attentions. A refill of oxygen in air is one of crucial solutions to improve air quality. In contrast to conventional technologies for oxygen production (i.e. physical separation of air, chemical reactions, water electrolysis), the innovative technology of electrochemical continuous separation of oxygen from air features separation of pure oxygen from air, high efficiency, continuous operation, environment friendly, silent operation, ease of scale up and applicability to indoor or outdoor fields. This technology involves two crucial components of polymer electrolyte fuel cells and solid polymer electrolyte water electrolysis (abbreviated as fuel cell and electrolyzer). In this article, the effect of operation conditions on single cell performance such as operation temperature, reactant gases utilization ratios, relative humidity and pressure,etc. for fuel cell was investigated, as well as the ways of water supply (at anode and/or cathode), water flow rate and operation temperature,etc. for electrolyzer. In terms of fuel cell, the polarization curve was measured, the electrochemical impedance spectra were conducted and the ionic conductivity and activation energy of Nafion? membrane were calculated. Polarization curve was fitted to obtain intrinsic parameters including Tafel slope, exchange current density of oxygen reduction reaction (i0) andm, n, related to mass transferetc. It showed that the optimum of fuel cell was under conditions of ambient pressure, 60℃ of operation temperature, 0.42 W·cm?2 of peak power density, 77 mohm·cm2 of cell areal resistance (membrane) and 41.4 mS·cm?1 of ionic conductivity. The Tafel slope slightly varied with temperature,ca. 120 mV·dec?1, but was influenced by the relative humidity. The relative humidity remarkably affected the fuel cell performances. In electrolyzer, the optimum was under

  10. Poor physician performance in the Netherlands: characteristics, causes, and prevalence.

    NARCIS (Netherlands)

    Goor, M.M.P.G. van den; Wagner, C.; Lombarts, K.M.J.M.H.

    2015-01-01

    Introduction: Poor physician performance has a profound impact on patient safety and society's trust in the health care system. The attention that this topic has received in the media suggests that it is a large-scale issue. However, research about physician performance is still scant; there is litt

  11. 78 FR 18988 - Establishing the Performance Characteristics of In Vitro Diagnostic Devices for the Detection of...

    Science.gov (United States)

    2013-03-28

    ... recommendations for studies to establish the analytical and clinical performance of in vitro diagnostic devices... studies for establishing the performance characteristics of in vitro diagnostic devices for the detection... HUMAN SERVICES Food and Drug Administration Establishing the Performance Characteristics of In...

  12. THE INFLUENCE OF SCREEN PARAMETERS ON PERFORMANCE CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    王汝林; A.C.Apling

    1996-01-01

    A series of laboratory screening tests have been performed with the objective of evaluating the effect of feed rate, screen length and screen motion on the quality of separation. The separation performance has been evaluated by the use of proposed ISO Standard measures which are based on the partition curve. The laboratory rig, the test programme and results derived from it are discussed. The effect of screen length, feed rate and screen motion on the levels of screen performance as indicated by these measures and a normalised separation size parameter are discussed in relation to the assumed screening conditions for the tests reported and conclusions are summarised.

  13. Performance characteristics between monolithic and microservice-based systems

    OpenAIRE

    Flygare, Robin; Holmqvist, Anthon

    2017-01-01

    A new promising technology to face the problem of scalability and availability is the microservice architecture. The problem with this architecture is that there is no significant study that clearly proves the performance differences compared to the monolithic architecture. Our thesis aims to provide a more conclusive answer of how the microservice architecture differs performance wise compared to the monolithic architecture. In this study, we conducted several experiments on a self-developed...

  14. Optimum testing of multiple hypotheses in quantum detection theory

    Science.gov (United States)

    Yuen, H. P.; Kennedy, R. S.; Lax, M.

    1975-01-01

    The problem of specifying the optimum quantum detector in multiple hypotheses testing is considered for application to optical communications. The quantum digital detection problem is formulated as a linear programming problem on an infinite-dimensional space. A necessary and sufficient condition is derived by the application of a general duality theorem specifying the optimum detector in terms of a set of linear operator equations and inequalities. Existence of the optimum quantum detector is also established. The optimality of commuting detection operators is discussed in some examples. The structure and performance of the optimal receiver are derived for the quantum detection of narrow-band coherent orthogonal and simplex signals. It is shown that modal photon counting is asymptotically optimum in the limit of a large signaling alphabet and that the capacity goes to infinity in the absence of a bandwidth limitation.

  15. Optimum Resolution in X-Ray Energy-Dispersive Diffractometry

    DEFF Research Database (Denmark)

    Buras, B.; Niimura, N.; Staun Olsen, J.

    1978-01-01

    The resolution problem in X-ray energy-dispersive diffractometry is discussed. It is shown that for a given characteristic of the solid-state detector system and a given range of interplanar spacings, an optimum scattering angle can be easily found for any divergence of the incident and scattered...

  16. Evaluating Performance Characteristics of SIP over IPv6

    Directory of Open Access Journals (Sweden)

    Thomas Hoeher

    2007-08-01

    Full Text Available Due to the ongoing massive growth of the global Internet, the rising integration of Voice over IP (VoIP services and the Fixed Mobile Convergence (FMC, the IPv6 protocol and the Session Initiation Protocol (SIP are key technologies for the realization of next generation communications. For both topics, IPv6 and SIP, a lot of self-contained research has been done. However, the challenge of SIP over IPv6 as well as related issues and performance impacts were not considered so far. In this article, we close this gap and draw attention to theoretical and practical aspects of the integration of SIP and IPv6, referred to as SIPv6. In this context our special interest concerns the interworking of heterogeneous IP networks during the transition from IPv4 to IPv6 and their ramifications on the VoIP service. Inevitably, during this period of co-existence the available transition techniques have an impact on the network and application performance. To quantify this impact, we set up a SIPv6 VoIP testbed and measured the performance penalties introduced by four selected transition techniques. We characterize the performance of transition scenarios compared to native scenarios by presenting measurement results and gained insights. Our study reveals individual pros and cons of transition technologies and their available implementations.

  17. Predicting Performance Under Acute Stress : The Role of Individual Characteristics

    NARCIS (Netherlands)

    Delahaij, R.; Dam, K. van; Gaillard, A.W.K.; Soeters, J.

    2011-01-01

    This prospective study examined how differences in coping style, coping self-efficacy, and metacognitive awareness influence coping behavior and performance during a realistic acute stressful exercise in 2 military samples (n = 122 and n = 132). Results showed that coping self-efficacy and coping st

  18. 淀粉-聚丙烯酰胺接枝共聚物的工艺优化与性能研究%Research on process optimum of starch graft polyacrylamide and its characteristics

    Institute of Scientific and Technical Information of China (English)

    张聪璐; 杨生强

    2011-01-01

    通过玉米淀粉接枝聚丙烯酰胺(PAM)制成了新型复合絮凝剂S-g-PAM,进行了影响接枝共聚物合成的单因素实验和正交实验,以对高岭土悬浊液的絮凝性能为评价指标.结果表明,最佳合成条件为,m(玉米淀粉):m(PAM)=3:0.001(质量比),NaOH:NaOCl=2:3(体积比),反应时间40 min,反应温度30 ℃,对高岭土溶液(110NTU)最佳去浊度效果为97%,投加量为30 mg/L.S-g-PAM使用的pH值范围为8~10,最佳温度范围20~40℃,与其它絮凝剂相比,其絮凝效果较好.%The new composite flocculant of starch-graft-polyacrylamide (S-g-PAM) was synthesized using starch and polyacrylamide as raw materials, the single element test, orthogonal test in the kaolin suspension were investigated.The results showed that the optimum conditions were as follows: the mass ratio of starch to PAM was 3 ∶0.001,the volume ratio of NaOH to NaOCl was 2 ∶3.reaction time was 40 min,reaction temperature was 30 ℃ ,the best removal rate of kaolin solution (110NTU) was 97% ,and the added dosage was 30 mg/L.The optimum using range of pH value was 8 ~ 10, the best using temperature range was 20 ~ 40 ℃ , compared with other flocculant, the flocculation effect of S-g-PAM was superior to others.

  19. Hydrofoils: optimum lift-off speed for sailboats.

    Science.gov (United States)

    Baker, R M

    1968-12-13

    For a hydrofoil sailboat there is a unique optimum lift-off speed. Before this speed is reached, if there are no parasitic vertical hydrofoil appendages, the submerged or partially submerged hydrofoils increase drag and degrade performance. As soon as this speed is reached and the hydrofoils are fully and promptly deployed, the performance of a hydrofoil-borne craft is significantly improved. At speeds exceeding optimum lift-off speed, partially submerged hydrofoils impair performance if there is no significant effect of loading on the hydrofoil lift-to-drag ratio.

  20. Crushing performance and resource characteristic of printed circuit board scrap

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; GU Guo-hua; QI Yun-feng

    2005-01-01

    The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especially vibration grinding, which has cut or impact action, excels that of jaw crusher or roller crusher. The PCB scrap is worthwhile to recycle using variety of modern characterization methods. When compared with natural resources, this material stream remains a rich precious metal and nonferrous metals. In PCB scrap, metals account for 47% of the total material composition, in which there exists 19.66% copper, 11.47% iron, 3.93% lead, 300 g/t gold and 5-10 kg/t silver, etc. In addition, the PCB scrap contains 27% of plastics and 26% of refractory oxides.

  1. Performance and emission characteristics of double biodiesel blends with diesel

    OpenAIRE

    Kuthalingam Arun Balasubramanian; Asokan Guruprasath; Marta Vivar; Skryabin Igor; Karuppian Srithar

    2013-01-01

    Recent research on biodiesel focused on performance of single biodiesel and its blends with diesel. The present work aims to investigate the possibilities of the application of mixtures of two biodiesel and its blends with diesel as a fuel for diesel engines. The combinations of Pongamia pinnata biodiesel, Mustard oil biodiesel along with diesel (PMD) and combinations of Cotton seed biodiesel, Pongamia pinnata biodiesel along with diesel (CPD) are taken for the experimental analysis. Ex...

  2. Pitching Flexible Propulsors: Experimental Assessment of Performance Characteristics

    Science.gov (United States)

    2014-05-09

    E. Motor The motor, shown in Fig. 16, manipulated the angular position of the propulsor using a proportional/integral/derivative ( PID ) controller...cogging torque. The motor also became easier to tune for higher frequency oscillations. The increased frequency corresponded to an increase in the...frequency to resonant frequency, may allow for proper tuning of flexible oscillation parameters for increased performance. Operating at or near a resonant

  3. Vocal Characteristics and Laryngoscopic Findings in Future Musical Theater Performers.

    Science.gov (United States)

    D'haeseleer, Evelien; Claeys, Sofie; Meerschman, Iris; Bettens, Kim; Degeest, Sofie; Dijckmans, Caroline; De Smet, Joke; Luyten, Anke; Van Lierde, Kristiane

    2017-07-01

    Musical theater performers are a special group of elite vocal performers with a high vocal load as they combine singing, acting, and physical performance. As they are absolutely depending on their voice quality and vocal capacities for their studies and their future profession, an optimal voice production is very important. The purpose of this study was to determine the voice quality of musical theater students. The voice quality of seven students was then reevaluated 1 year after the first assessment. Observational study. Thirty-one musical students (7 men and 24 women) with a mean age of 20 years participated in the study. To determine the voice quality, objective (aerodynamic measurements, voice range profile, acoustic analysis, and Dysphonia Severity Index) and subjective (videolaryngostroboscopy, Voice Handicap Indexes, and questionnaires regarding voice symptoms and risk factors) voice measurements were performed. The median Dysphonia Severity Index in male and female musical students was respectively 5.3 and 5.7, both corresponding with an overall good voice quality. The questionnaires revealed the presence of vocal fatigue, dryness of the throat, vocal tract discomfort, and harmful vocal habits in the majority of students. In 45% of the subjects, videolaryngostroboscopic evaluation of the vocal folds showed an organic lesion. The majority of these lesions are inflammatory lesions (26%). In 68% of the subjects, a certain degree of supraglottic constriction was observed. Despite the overall good voice quality, videolaryngostroboscopy showed a high presence of vocal fold lesions and supraglottic constriction during phonation. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  4. On-the-Move Nutrient Delivery System Performance Characteristics

    Science.gov (United States)

    2008-09-01

    concentrations or brix were used to assess NDS performance. A variety of carbohydrate formulations were also studied to define the ideal concentrate for...glucose concentration (7100 MBS, Yellow Springs) or % soluble solids( Brix : PR-1 digital refractometer, Atago). Where glucose measurements were made, samples...Triplicate samples were collected at each NOS position, and the Brix in each sip measured. Statistical Analysis. Descriptive statistics were

  5. Characteristics of sprint performance in college football players.

    Science.gov (United States)

    Brechue, William F; Mayhew, Jerry L; Piper, Fontaine C

    2010-05-01

    To investigate sprinting strategy, acceleration and velocity patterns were determined in college football players (n = 61) during performance of a 9.1-, 36.6-, and 54.9-m sprints. Acceleration and velocity were determined at 9.1-m intervals during each sprint. Lower-body strength and power were evaluated by 1 repetition maximum (1-RM) squat, power clean, jerk, vertical jump, standing long jump, and standing triple jump. Sprint times averaged 1.78 +/- 0.11 seconds (9.1 m), 5.18 +/- 0.35 seconds (36.6 m), and 7.40 +/- 0.53 seconds. Acceleration peaked at 9.1 m (2.96 +/- 0.44 m x s(-2)), was held constant at 18.3 m (3.55 +/- 0.0.94 m x s(-2)), and was negative at 27.4 m (-1.02 +/- 0.72 m x s(-2)). Velocity peaked at 18.3 m (8.38 +/- 0.65 m x s(-2)) and decreased slightly, but significantly at 27.4 m (7.55 +/- 0.66 m x s(-2)), associated with the negative acceleration. Measures of lower-body strength were significantly related to acceleration, velocity, and sprint performance only when corrected for body mass. Lower-body strength/BM and power correlated highest with 36.6-m time (rs = -0.55 to -0.80) and with acceleration (strength r = 0.67-0.49; power r = 0.73-0.81) and velocity (strength r = 0.68-0.53; power r = 0.74-0.82) at 9.1 m. Sprint times and strength per body mass were significantly lower in lineman compared with linebackers-tight ends and backs. The acceleration and velocity patterns were the same for each position group, and differences in sprint time were determined by the magnitude of acceleration and velocity at 9.1 and 18.3 m. Sprint performance in football players is determined by a rapid increase in acceleration (through 18.3 m) and a high velocity maintained throughout the sprint and is independent of position played. The best sprint performances (independent of sprint distance) appear to be related to the highest initial acceleration (through 18.3 m) and highest attained and maintained velocity. Strength relative to body mass and power appears to

  6. Study of Relationships between Apparel Manufacturers' Supply Chain Management, Company Characteristics, and Inventory Performance

    OpenAIRE

    Lee, Yuri

    1999-01-01

    The purpose of this study is to examine apparel manufacturers' inventory performance, which is one of the major performance indicators of supply chain management (SCM) with the consideration of company characteristics. The objectives of the study are (a) to identify the level of SCM activities of apparel manufacturers, (b) to examine the differences of apparel manufacturers' characteristics (i.e., product characteristic, production system, fabric suppliers, retail customers) according to the ...

  7. Study of Relationships between Apparel Manufacturers' Supply Chain Management, Company Characteristics, and Inventory Performance

    OpenAIRE

    Lee, Yuri

    2000-01-01

    The purpose of this study is to examine apparel manufacturers' inventory performance, which is one of the major performance indicators of supply chain management (SCM) with the consideration of company characteristics. The objectives of the study are (a) to identify the level of SCM activities of apparel manufacturers, (b) to examine the differences of apparel manufacturers' characteristics (i.e., product characteristic, production system, fabric suppliers, retail customers) according to the ...

  8. Influence of dietary non-phytate phosphorous levels and phytase supplementation on the performance and bone characteristics of broilers

    Directory of Open Access Journals (Sweden)

    A Karimi

    2011-03-01

    Full Text Available Precise phosphorus nutrition is important for significant reductions in both P pollution and ration costs. The influence of different levels (% of dietary nPP fed from 0 to 20 d (0.45, 0.40, 0.35, 0.30, 0.25, compared with feeding 0.20 nPP with and without 500 F.T.U. of phytase per kg of diet and from 21 to 36 d of age (0.414, 0.364, 0.314, 0.264, 0.214, compared with 0.164 nPP with and without 500 F.T.U. of phytase per kg of diet were evaluate using a total of 588 day-old commercial broiler chicks. Each treatment was replicated four times in a completely randomized design. Body weight (BW, daily gain (DG, feed intake (DFI, feed conversion ratio, plasma P level and bone characteristics were determined, and from these data the P equivalency of the phytase was estimated. Feeding diets containing less than 0.40% of nPP to birds between 0 and 20d resulted in inferior BW, DFI, plasma P level and bone characteristics compared with the control. However, optimum FCR and mortality was supported at lower levels of nPP (0.25%. Between 21 and 36 d, 0.364% was enough to optimise BW, DFI, and femur ash (%; whilst only 0.314% or greater was needed to support optimum DG, toe and tibia ash and only 0.214 to 0.264% was required to optimise shank, femur and tibia lengths; FCR and survivability. A broken line analysis also showed that the nPP (% requirement ranged from 0.267 to 0.410 and 0.272 to 0.380% during 0 to 20 and 21 to 36 d, respectively. Phytase supplementation improved performance and bone criterion and its P equivalency, depending upon the response of interest and birds age, ranged from 0.00 to 0.110%. In conclusion, the results showed that the combination of a lower level of nPP and phytase may be used to increase dietary P utilization, without severe changes in performance and bone quality.

  9. Performance characteristics of commercial Y-STR multiplex systems.

    Science.gov (United States)

    Mayntz-Press, Kathleen A; Ballantyne, Jack

    2007-09-01

    In this work, a number of performance checks were carried out to evaluate the efficacy of commercial Y-short tandem repeats (Y-STR) kits for casework applications. The study evaluated the sensitivity, specificity and stability of the Y-STR markers used and the ability to obtain a male profile from postcoital samples taken at various time points after intercourse. All systems performed well with 1-3 ng of male DNA as recommended by the manufacturers. All systems gave full profiles at 100 pg of input DNA, which is within the realm of low copy number DNA analysis. Moreover all, except Y-Plex12, gave full profiles with 30-50 pg of male DNA. No increased performance was obtained with any of the systems by increasing the cycle number beyond that recommended by the various manufacturers. When up to 1 microg of female DNA was used (in the absence of male DNA) no female DNA cross reactivity was observed with the Y-Plex 12 and Y-Filer systems. PowerPlex Y produced female DNA derived products near the DYS438 and within the DYS392 loci at a rare allele position with high input DNA levels (300 ng and 1 microg, respectively). Male/female DNA admixture experiments indicated the particularly high specificity of the Y-Filer and PowerPlex Y systems under conditions of several thousand fold female DNA excess. All systems were able to detect the minor alleles in male/male DNA admixtures at a 1:5 dilution with the PowerPlex Y and Y-Filer being able to detect some minor alleles at 1:20. Species testing indicated some limited, minor cross reactivity of the commercial systems with some domestic male mammals although it is easily recognizable and would not pose any problems in casework analysis. As expected a significant number of cross-reacting products were obtained with nonhuman primate species. All Y-STR multiplex systems tested were able to produce complete Y-STR profiles from bloodstains and semen stains exposed up to 6 weeks when the samples were protected against precipitation and

  10. Performance characteristics of a cosmology package on leading HPCarchitectures

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Jonathan; Borrill, Julian; Oliker, Leonid

    2004-01-01

    The Cosmic Microwave Background (CMB) is a snapshot of the Universe some 400,000 years after the Big Bang. The pattern of anisotropies in the CMB carries a wealth of information about the fundamental parameters of cosmology. Extracting this information is an extremely computationally expensive endeavor, requiring massively parallel computers and software packages capable of exploiting them. One such package is the Microwave Anisotropy Dataset Computational Analysis Package (MADCAP) which has been used to analyze data from a number of CMB experiments. In this work, we compare MADCAP performance on the vector-based Earth Simulator (ES) and Cray X1 architectures and two leading superscalar systems, the IBM Power3 and Power4. Our results highlight the complex interplay between the problem size, architectural paradigm, interconnect, and vendor-supplied numerical libraries, while isolating the I/O file system as the key bottleneck across all the platforms.

  11. Performance and Carcass Characteristics of Rabbits Fed Oil Supplemented Diets

    Directory of Open Access Journals (Sweden)

    Jamal Abo OMAR

    2016-02-01

    Full Text Available The objective of this study is to investigate the effects of feeding different dietary fat supplements in the finisher rations of Baladi rabbits, including sesame oil (SO, olive oil sediments (OOS, and poultry grease (PG, in comparison to the traditional oil supplement, the soybean soap stock oil (SS, on growth performance, blood lipid profile, dressing percentage and carcass cut, and meat quality: water holding capacity (WHC and cell forming unit (CFU. A total of 48 Baladi rabbits were used, with individual body weights (BW of 519 ± 22 g at the beginning of the experiment. Rabbits were randomly divided into 4 groups of 12, and those in each group were individually fed cereal grain-soybean meal (SBM with a fixed amount (i.e. 30 g/kg dry matter (DM of oil, being either soybean oil (SOY, olive oil sediments (OOS, recycled restaurant oil (RRO, or poultry grease (PG. All rations were isonitrogenous and contained iso-metabolizable energy (ME. At the end of the 44 day feeding trial, all animals were slaughtered. Rabbits fed a SOY supplemented diet consumed more (P < 0.05 feed than those fed the OOS, RRO, or PG supplemented diets. However, rabbits fed the SOY had a better (P < 0.05 feed conversion ratio than rabbits fed the OOS, PG, or RRO diets. Oil source had no effect on carcass components weights. Liver was heavier (P < 0.05 in rabbits fed the SOY supplemented diet. However, the RRO fed rabbits had heavier (P < 0.05 small intestine, large intestine and cecum. In conclusion, the positive effects of the tested oil supplements (i.e. RRO, OOS, PG on the studied performance and carcass traits is encouraging, but more investigation is needed to identify the optimal levels for these supplements in various diets of local rabbits.

  12. Multi-Objective Fuzzy Optimum Design Based on Reliability for Offshore Jacket Platforms

    Institute of Scientific and Technical Information of China (English)

    康海贵; 刘未; 翟钢军; 徐发淙; 封盛

    2001-01-01

    In consideration of the fuzzy constraint boundary and through analysis of structural reliability, a model of structural fuzzy optimum design is established based on reliability for offshore jacket platforms. According to the characteristics of offshore jacket platforms, the tolerance coefficient of the constraint boundary is determined with the fuzzy optimization method. The optimum level cut set λ *, which is the intersection of the fuzzy constraint set and fuzzy objective set, is determined with the bound search method, and then the fuzzy optimum solution to the fuzzy optimization problem is obtained. The central offshore platform SZ36-1 is designed with the fuzzy optimum model based on reliability; the results are compared with those from deterministic optimum design and fuzzy optimum design. The tendency of design variables in the above three methods and its reasons are analyzed. The results of an example show that the fuzzy optimum design based on reliability is stable and reliable.

  13. NEXT Long-Duration Test Neutralizer Performance and Erosion Characteristics

    Science.gov (United States)

    Herman, Daniel A.; Soulas, George C.; Patterson, Michael J.

    2009-01-01

    The NASA's Evolutionary Xenon Thruster (NEXT) program is developing the next-generation ion propulsion system with significant enhancements beyond the state-of-the-art to provide future NASA science missions with enhanced capabilities at a low total development cost. A Long-Duration Test (LDT) was initiated in June 2005, to verify the NEXT propellant throughput capability to a qualification-level of 450 kg, 1.5 times the anticipated throughput requirement of 300 kg per thruster based on mission analyses. As of September 2, 2009, the thruster has accumulated 24,400 hr of operation with extensive durations at the following input powers: 6.9, 4.7, 1.1, and 0.5 kW. The thruster has processed 434 kg of xenon, surpassing the NASA Solar Technology Application Readiness (NSTAR) program thruster propellant throughput demonstrated during the extended life testing of the Deep Space 1 flight spare ion thruster and approaching the NEXT development qualification throughput goal of 450 kg. The NEXT LDT has demonstrated a total impulse of 16.1 10(exp 6zzz0 N s; the highest total impulse ever demonstrated by an ion thruster. A reduction in neutralizer flow margin has been the only appreciable source of thruster performance degradation. The behavior of the neutralizer is not easily predicted due to both erosion and deposition observed in previous wear tests. Spot-to-plume mode transition flow data and in-situ erosion results for the LDT neutralizer are discussed. This loss of flow margin has been addressed through a combination of a design change in the prototype-model neutralizer to increase flow margin at low emission current and to update the NEXT throttle table to ensure adequate flow margin as a function of propellant throughput processed. The new throttle table will be used for future LDT operations. The performance of the NEXT LDT neutralizer is consistent with that observed for long-life hollow cathodes. The neutralizer life-limiting failure modes are progressing as expected

  14. Separator Characteristics for Increasing Performance of Microbial Fuel Cells

    KAUST Repository

    Zhang, Xiaoyuan

    2009-11-01

    Two challenges for improving the performance of air cathode, single-chamber microbial fuel cells (MFCs) include increasing Coulombic efficiency (CE) and decreasing internal resistance. Nonbiodegradable glass fiber separators between the two electrodes were shown to increase power and CE, compared to cloth separators (J-cloth) that were degraded over time. MFCtestswereconductedusing glass fibermatswith thicknesses of 1.0mm (GF1) or 0.4 mm (GF0.4), a cation exchange membrane (CEM), and a J-cloth (JC), using reactors with different configurations. Higher power densities were obtained with either GF1 (46 ± 4 W/m3) or JC (46 ± 1 W/m3) in MFCs with a 2 cm electrode spacing, when the separator was placed against the cathode (S-configuration), rather than MFCs with GF0.4 (36 ± 1 W/m3) or CEM (14 ± 1 W/m3). Power was increased to 70 ± 2 W/m3 by placing the electrodes on either side of the GF1 separator (single separator electrode assembly, SSEA) and further to 150 ± 6 W/m3 using two sets of electrodes spaced 2 cm a part (double separator electrode assembly, DSEA). Reducing the DSEA electrode spacing to 0.3 cm increased power to 696 ± 26 W/m3 as a result of a decrease in the ohmic resistance from 5.9 to 2.2 Ω. The main advantages of a GF1 separator compared to JC were an improvement in the CE from 40% to 81% (S-configuration), compared to only 20-40% for JC under similar conditions, and the fact that GF1 was not biodegradable. The high CE for the GF1 separator was attributed to a low oxygen mass transfer coefficient (ko ) 5.0 x 10-5 cm/s). The GF1 andJCmaterials differed in the amount of biomass that accumulated on the separator and its biodegradability, which affected long-term power production and oxygen transport. These results show that materials and mass transfer properties of separators are important factors for improving power densities, CE, and long-term performance of MFCs. © 2009 American Chemical Society.

  15. Performance characteristics of a submarine panoramic infrared imaging sensor

    Science.gov (United States)

    Nichols, J. M.; Waterman, J. R.; Menon, Raghu; Devitt, John

    2010-04-01

    A high-resolution mid-wave infrared panoramic periscope sensor system has been developed. The sensor includes a catadioptric optical system that provides a 360° horizontal azimuth by -10° to +30° elevation field of view without requiring moving components (e.g. rotating mirrors). The focal plane is a 2048 x 2048, 15μm pitch InSb detector operating at 80K. An on-board thermo-electric reference source allows for real-time nonuniformity correction using the two-point correction method. The entire system (detector-dewar assembly, cooler, electronics and optics) is packaged to fit in an 8" high, 6.5" diameter volume. This work describes both the system optics and electronics and presents sample imagery. We also discuss the sensor's radiometric performance, quantified by the NEDT, as a function of key system parameters. The ability of the system to resolve targets as a function of imaged spatial frequency is also presented.

  16. Performance characteristics of the novel PETRRA positron camera

    CERN Document Server

    Ott, R J; Erlandsson, K; Reader, A; Duxbury, D; Bateman, J; Stephenson, R; Spill, E

    2002-01-01

    The PETRRA positron camera consists of two 60 cmx40 cm annihilation photon detectors mounted on a rotating gantry. Each detector contains large BaF sub 2 scintillators interfaced to large area multiwire proportional chambers filled with a photo-sensitive vapour (tetrakis-(dimethylamino)-ethylene). The spatial resolution of the camera has been measured as 6.5+-1.0 mm FWHM throughout the sensitive field-of-view (FoV), the timing resolution is between 7 and 10 ns FWHM and the detection efficiency for annihilation photons is approx 30% per detector. The count-rates obtained, from a 20 cm diameter by 11 cm long water filled phantom containing 90 MBq of sup 1 sup 8 F, were approx 1.25x10 sup 6 singles and approx 1.1x10 sup 5 cps raw coincidences, limited only by the read-out system dead-time of approx 4 mu s. The count-rate performance, sensitivity and large FoV make the camera ideal for whole-body imaging in oncology.

  17. Runway drainage characteristics related to tire friction performance

    Science.gov (United States)

    Yager, Thomas J.

    1991-01-01

    The capability of a runway pavement to rapidly drain water buildup during periods of precipitation is crucial to minimize tire hydroplaning potential and maintain adequate aircraft ground operational safety. Test results from instrumented aircraft, ground friction measuring vehicles, and NASA Langley's Aircraft Landing Dynamics Facility (ALDF) track have been summarized to indicate the adverse effects of pavement wetness conditions on tire friction performance. Water drainage measurements under a range of rainfall rates have been evaluated for several different runway surface treatments including the transversely grooved and longitudinally grinded concrete surfaces at the Space Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center in Florida. The major parameters influencing drainage rates and extent of flooding/drying conditions are identified. Existing drainage test data are compared to a previously derived empirical relationship and the need for some modification is indicated. The scope of future NASA Langley research directed toward improving empirical relationships to properly define runway drainage capability and consequently, enhance aircraft ground operational safety, is given.

  18. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    Science.gov (United States)

    Kwon, Yo Han; Huie, Matthew M; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Reichmanis, Elsa

    2016-02-10

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. The study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  19. Thermophilic biofilter for SO2 removal: performance and microbial characteristics.

    Science.gov (United States)

    Zhang, Jingying; Li, Lin; Liu, Junxin

    2015-03-01

    A bench-scale thermophilic biofilter was applied to remove SO2 at 60°C in the present study. The SO2 concentration in the inlet stream ranged from 100mg/m(3) to 200mg/m(3). An average SO2 removal efficiency of 93.10% was achieved after developing acclimated organisms that can degrade SO2. The thermophilic biofilter effectively reduced SO2, with a maximum elimination capacity of 50.67g/m(3)/h at a loading rate of 51.44g/m(3)/h. Removal efficiency of the thermophilic biofilter was largely influenced by the water containing rate of the packing materials. The SO2 transfer in the biofilter included adsorption by the packing materials, dissolution in liquid, and microbial degradation. The main product of SO2 degradation was SO4(2-). The temporal shifts in the bacterial community that formed in the biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and DNA sequence analysis. These shifts revealed a correlation between biofilter performance and bacterial community structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Effects of Zeolite (Clinoptelolite on Performance Characteristics of

    Directory of Open Access Journals (Sweden)

    A Hassan Abadim

    2011-12-01

    Full Text Available A 70-days experiment was conducted to investigate the effects of natural zeolite (clinoptelolite on the performance of commercial laying hens. 288 Hy-Line W36 strain laying hens (50 weeks old were allotted to 6 dietary treatments including basal diet as control and basal diet supplemented with 1, 2, 3, 4 and 5% zeolite that were fed ad -libitum throughout the experiment. Experimental diets for the 6 treatments were prepared to be iso-caloric and iso-nitrogenous. A completely randomized design with six treatments, eight replicates of six birds per replicate was used at this experiment. Daily feed intake (DFI, feed conversion ratio (FCR, egg production, egg weight, egg white quality, eggshell quality (thickness and percentage and body weight changes were measured during the experiment. Results of this experiment showed that DFI, FCR, egg production and egg abnormality were not significantly (P>0.05 affected by zeolite supplementation. Zeolite supplementation significantly increased egg weight, eggshell thickness and live body weight gain of the hens. Dietary zeolite significantly decreased haugh unit of the eggs. In conclusion, natural zeolite significantly improved egg weight and eggshell quality, decreased haugh unit and live weight gain, and had no significant effects on other parameters.

  1. Lubrifiants extrême-pression pour engrenages. Aspects chimiques de l'optimisation des performances mécaniques Extreme-Pressure Gear Lubricants: Chemical Aspects for Obtaining Optimum Mechanical Performances

    Directory of Open Access Journals (Sweden)

    Born M.

    2006-11-01

    plusieurs types de dérivés sulfurés et/ou phosphorés sera parfois nécessaire. Enfin, des additifs complémentaires : anticorrosion, en particulier pour protéger les métaux cuivreux, antirouille, antimousse, réducteur de frottement seront sélectionnés en évitant des interactions préjudiciables aux performances mécaniques. La formulation d'additifs destinés aux lubrifiants extrême-pression pour engrenages nécessite donc un choix judicieux des composants de sorte que chacun d'entre-eux puisse assumer correctement sa fonction pour une durée aussi longue que possible. Optimal conditions for engine efficiency rarely correspond to the needs of the end use of energy insofar as rpm and torque are concerned. This is why intermediary mechanisms are needed for making the necessary adjustments, i. e. reducing gears, gear boxes (manual or automatic, transfer cases and rear axles. Modern technology, particularly for transportation, requires the reduction of both the mass and volume of such mechanisms, meaning that greater and greater specific loads must pass through gears. Despite technological progress made in designing and manufacturing gears, their proper lubrication remains a determinant factor. The lubrication of heavily loaded gears requires the use of chemical components called extreme-pressure additives . Among them, phosphorus and sulfur combinations are widely used in industry and will be the only ones considered in this article. Sulfur is the element most often used to obtain extreme-pressure properties. It forms an easily sheared film of iron sulfide on microweldings. Sulfur is present in oil as organic sulfides or polysulfides, but its lability must be adjusted to have a solely local effect without causing any corrosion. A good understanding of the relations between the structure and mechanical properties of polysulfides is required for optimizing the structure of industrial additives. Antiwear properties are usually provided by phosphorus compounds, i. e

  2. Research about reactor operator's personability characteristics and performance

    Energy Technology Data Exchange (ETDEWEB)

    Wei Li; He Xuhong; Zhao Bingquan [Tsinghua Univ., Institute of Nuclear Energy Technology, Beijing (China)

    2003-03-01

    To predict and evaluate the reactor operator's performance by personality characteristics is an important part of reactor operator safety assessment. Using related psychological theory combined with the Chinese operator's fact and considering the effect of environmental factors to personality analysis, paper does the research about the about the relationships between reactor operator's performance and personality characteristics, and offers the reference for operator's selection, using and performance in the future. (author)

  3. Analytical and numerical investigation of the optimum pressure distribution along a low-pressure axial fan blade

    OpenAIRE

    2013-01-01

    In the field of axial flow turbomachines, the two-dimensional cascade model is often used experimentally or numerically to investigate fundamental flow characteristics and overall performance of the impeller. The core of the present work is a design method for axial fan cascades aiming to derive inversely the optimum blade shape based on the requirements of the impeller and not using any predefined aerofoil profiles. While most design strategies based on the aerofoil theory assume constant to...

  4. The Optimum Growth Rate for Population Reconsidered

    OpenAIRE

    Jaeger, Klaus; Kuhle, Wolfgang

    2007-01-01

    This article gives exact general conditions for the existence of an interior optimum growth rate for population in the neoclassical two-generations-overlapping model. In an economy where high (low) growth rates of population lead to a growth path which is efficient (inefficient) there always exists an interior optimum growth rate for population. In all other cases there exists no interior optimum. The Serendipity Theorem, however, does in general not hold in an economy with government debt. M...

  5. The Electric Parameters Characteristics and Optimum Design of Electromagnetic Railgun%电磁轨道炮的电气参数特性研究及优化设计

    Institute of Scientific and Technical Information of China (English)

    谭赛; 鲁军勇

    2012-01-01

    The operation principle and equivalent circuit of electromagnetic railgun are analyzed, and model is built and simulated. The influence of main electric parameters and trigger time sequence of source modules on muzzle velocity is studied. Some principles of optimum design for electromagnetic railgun are presented to increase the muzzle velocity and extend the length of rail life synchronously by reducing the impact of current on rail, such as rational design the rail shape and selection of appropriate rail material in order to increase the inductance gradient and decrease the resistance gradient, regulation of pulse forming inductance and capacitor to decrease the peak value time, and increasing the peak value of current, capacitive storage power supply consist of modules triggered by time sequence control.%分析了电磁轨道炮的工作原理和等效电路,对其进行了建模仿真。研究了电磁轨道炮各主要电气参数、电源模块放电时序对电枢速度的影响。提出了电磁轨道炮优化设计的原则,如合理设计轨道形状,选取适当的材料,以提高电感梯度、降低电阻梯度;合理调节调波电感、储能电容器等参数以减小脉冲电流峰值时间、提高电流峰值大小;电容储能式电源采用模块化设计,并采用时序控制触发放电模式,形成合成幅值较大,持续时间较长的平顶波电流,提高弹丸的出膛速度,减少对轨道的冲击,延长轨道的寿命。

  6. South African exporter performance: new research into firm-specific and market characteristics

    Directory of Open Access Journals (Sweden)

    Christopher May

    2012-05-01

    Full Text Available The export marketing performance of any firm is influenced by a multitude of different factors. Given the multi-faceted nature of the export market, this research study investigated specific factors such as how firm-specific characteristics, product characteristics, market characteristics and export marketing strategies impact on the export marketing performance of South African manufacturing firms. Some of the findings of this research study indicated that firm size, investment commitment and careful planning, as firm-specific characteristics, had a significant influence on export marketing performance. The relationship between export experience and export marketing performance was insignificant. The degree of pricing adaptation and product adaptation had a significant effect on export marketing performance, while this was not the case with respect to the degree of promotion adaptation and distributor support.

  7. Investigations on the optimum design of chemical addition system for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Byong Hoon [Junior College of Inchon, Inchon (Korea, Republic of); Chung, Chang Kyu; Choi, Han Rim; Kim, Eun Kee; Ro, Tae Sun [Korea Power Engineering Company, Inc. Taejon (Korea, Republic of)

    1997-12-31

    Mixing characteristics of the chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5 and 6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet. 10 refs., 4 figs. (Author)

  8. Relationship between performance at different exercise intensities and skeletal muscle characteristics

    DEFF Research Database (Denmark)

    Iaia, F Marcello; Perez-Gomez, Jorge; Thomassen, Martin

    2011-01-01

    The hypothesis investigated whether exercise performance over a broad range of intensities is determined by specific skeletal muscle characteristics. Seven subjects performed 8-10 exhaustive cycle trials at different work loads ranging from 150 to 700 W (150 min - 20 s). No relationships between...... the performance times at high and low work loads were observed. A relationship (P...

  9. Temperature of optimum generation in facilities of solar cold making use of the equation characteristic; Temperatura de generacion optima en instalaciones de frio solar haciendo uso de la ecuacion caracteristica

    Energy Technology Data Exchange (ETDEWEB)

    Leucona, A.; Ventas, R.; Venegas, M. del C.; Zacarias, A.; Salgado, R.

    2008-07-01

    Absorption machines show a similar response as a function of the external temperatures, which can be approximated by a single functional dependence of the named characteristic temperature. This equation and the normalization curve of the solar thermal collector field driving the chiller and some more approximations allow determining the driving temperature that maximizes the cooling power at any time. This results in a simple equation. It is offered for the design of solar cooling facilities and their control algorithms. Some results are offered and discussed. (Author)

  10. Examining the Relationship between Learning Organization Characteristics and Change Adaptation, Innovation, and Organizational Performance

    Science.gov (United States)

    Kontoghiorghes, Constantine; Awbre, Susan M.; Feurig, Pamela L.

    2005-01-01

    The main purpose of this exploratory study was to examine the relationship between certain learning organization characteristics and change adaptation, innovation, and bottom-line organizational performance. The following learning organization characteristics were found to be the strongest predictors of rapid change adaptation, quick product or…

  11. Relationship characteristics and performance in fresh produce supply chains: the case of the Mexican avocado industry

    NARCIS (Netherlands)

    Coronado, J.J.A.; Bijman, J.; Omta, S.W.F.; Oude Lansink, A.G.J.M.

    2010-01-01

    Abstract Inter-organisational relations research has shown that relationship characteristics can influence performance in seller-buyer transactions. Using a transaction cost economics approach, this research shows that relational elements such as expectation of continuity reduce the transaction risk

  12. Prebiotic and antimicrobials on performance, carcass characteristics, and antibody production in broilers

    National Research Council Canada - National Science Library

    Fomentini, Maíra; Haese, Douglas; Kill, João Luís; Sobreiro, Rodrigo Pereira; Puppo, Débora Del; Haddade, Ismail Ramalho; Lima, Anderson Lazarini; Saraiva, Alysson

    2016-01-01

    To evaluate the effect of supplementation with mannan oligosaccharides, avilamycin and halquinol, alone or in combination, on the performance, carcass characteristics and antibody production in broilers (1-49 days old...

  13. Cooling Performance Characteristics on Mobile Air-Conditioning System for Hybrid Electric Vehicles

    OpenAIRE

    Ho-Seong Lee; Moo-Yeon Lee

    2013-01-01

    This study investigates the cooling performance characteristics of the mobile air-conditioning system using R744 (CO2) for the hybrid electric vehicle as an alternative to both the R-134a and the conventional air-conditioning system. The developed air-conditioning system is operated with an electric driven compressor in the battery driving mode and a belt driven compressor in the engine driving mode. The cooling performance characteristics of the developed system have been analyzed by experim...

  14. Mutual Fund Style, Characteristic-Matched Performance Benchmarks and Activity Measures: A New Approach

    OpenAIRE

    Daniel Buncic; Jon E. Eggins; Robert J. Hill

    2010-01-01

    We propose a new approach for measuring mutual fund style and constructing characteristic-matched performance benchmarks that requires only portfolio holdings and two reference portfolios in each style dimension. The characteristic-matched performance benchmark literature typically follows a bottom-up approach by first matching individual stocks with benchmarks and then obtaining a portfolio’s excess return as a weighted average of the excess returns on each of its constituent stocks. Our app...

  15. Site survey for optimum location of Optical Communication Experimental Facility

    Science.gov (United States)

    1968-01-01

    Site survey was made to determine the optimum location for an Optical Communication Experimental Facility /OCEF/ and to recommend several sites, graded according to preference. A site was desired which could perform two-way laser communication with a spacecraft and laser tracking with a minimum of interruption by weather effects.

  16. Noncommutative QED Threshold Energy versus Optimum Collision Energy

    Institute of Scientific and Technical Information of China (English)

    SHENG Zheng-Mao; FU Yong-Ming; YU Hai-Bo

    2005-01-01

    @@ M(o)11er scattering and Bhabha scattering on noncommutative (NC) space-time is restudied. It is shown that the NC correction of scattering sections is not monotonic enhancement with total energy of colliding electrons, that there is an optimum collision energy to perform the greatest NC correction.

  17. Board Characteristics Best Practices and Financial Performance. Evidence from the European Capital Market

    Directory of Open Access Journals (Sweden)

    Victor-Octavian Müller

    2014-05-01

    Full Text Available This study investigates board characteristics best practices in the particular context of European listed companies. The theoretical grounding of the paper is done by discussing board composition and board compensation related studies, mainly belonging to the corporate governance literature. The main objective of the paper is to contribute to the debate on whether certain board characteristics can be documented to represent best practices. In doing so, we investigate if such board characteristics significantly influence companies’ financial performance. We use econometric regression models in order to assess the impact of a series of corporate governance board related characteristics on the performance of companies (constituents of FTSE100 listed on the largest European capital market (London Stock Exchange, for the 2010-2011 period. An accounting measure of operating performance, namely the operating return on assets (ROA, is used. The profoundness of a potential impact of corporate board characteristics on companies’ performance is investigated by considering both contemporaneous and subsequent operating performance. Results document best practices through the existence of several significant associations between considered board characteristics and firm performance

  18. Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

    Directory of Open Access Journals (Sweden)

    Omer Kaynakli

    2011-06-01

    Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

  19. A high unburned carbon fly ash concrete’s performance characteristics

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Valderrama

    2011-01-01

    Full Text Available Engineering today requires that structures are strong and durable; the latter concept is a decisive factor in their design and construction. The scientific community continues developing new cementitious materials and improving tra-ditional concrete’s properties, specifically reducing permeability by incorporating materials such as pozzolans. This paper analyses the effect of fly ash (FA added to concrete on mechanical strength regarding compression, capillary absorption and chloride permeability and their behaviour compared to concrete containing silica fume (SF. An optimum 10% mechanical strength was found for fly ash; however, this increased with addition, resulting in positive effects on durability. Fly ash had lower performance for all properties evaluated when compared to silica fume.

  20. A class of optimum digital phase locked loops

    Science.gov (United States)

    Kumar, R.; Hurd, W. J.

    1986-01-01

    This paper presents a class of optimum digital filters for digital phase locked loops, for the important case in which the maximum update rate of the loop filter and numerically controlled oscillator (NCO) is limited. This case is typical when the loop filter is implemented in a microprocessor. In these situations, pure delay is encountered in the loop transfer function and thus the stability and gain margin of the loop are of crucial interest. The optimum filters designed for such situations are evaluated in terms of their gain margin for stability, dynamic error, and steady-state error performance. For situations involving considerably high phase dynamics an adaptive and programmable implementation is also proposed to obtain an overall optimum strategy.

  1. Error Exponents of Optimum Decoding for the Interference Channel

    CERN Document Server

    Etkin, Raul; Ordentlich, Erik

    2008-01-01

    Exponential error bounds for the finite-alphabet interference channel (IFC) with two transmitter-receiver pairs, are investigated under the random coding regime. Our focus is on optimum decoding, as opposed to heuristic decoding rules that have been used in previous works, like joint typicality decoding, decoding based on interference cancellation, and decoding that considers the interference as additional noise. Indeed, the fact that the actual interfering signal is a codeword and not an i.i.d. noise process complicates the application of conventional techniques to the performance analysis of the optimum decoder. Using analytical tools rooted in statistical physics, we derive a single letter expression for error exponents achievable under optimum decoding and demonstrate strict improvement over error exponents obtainable using suboptimal decoding rules, but which are amenable to more conventional analysis.

  2. Performance Characteristics of a PEM Fuel Cell with Parallel Flow Channels at Different Cathode Relative Humidity Levels

    OpenAIRE

    Sang Soon Hwang; Pil Hyong Lee

    2009-01-01

    In fuel cells flow configuration and operating conditions such as cell temperature, humidity at each electrode and stoichiometric number are very crucial for improving performance. Too many flow channels could enhance the performance but result in high parasite loss. Therefore a trade-off between pressure drop and efficiency of a fuel cell should be considered for optimum design. This work focused on numerical simulation of the effects of operating conditions, especially cathode humidity, wit...

  3. Standard guide for evaluating performance characteristics of phased-Array ultrasonic testing instruments and systems

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This guide describes procedures for evaluating some performance characteristics of phased-array ultrasonic examination instruments and systems. 1.2 Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this guide are expressed in terms that relate to their potential usefulness for ultrasonic examinations. Other electronic instrument characteristics in phased-array units are similar to non-phased-array units and may be measured as described in E 1065 or E 1324. 1.3 Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be evaluated. 1.4 This guide establishes no performance limits for examination systems; if such acceptance criteria ar...

  4. Determination of optimum pressurizer level for kori unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Song, Dong Soo; Lee, Chang Sup; Lee Jae Yong; Kim, Yo Han; Lee, Dong Hyuk [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    To determine the optimum pressurizer water level during normal operation for Kori unit 1, performance and safety analysis are performed. The methodology is developed by evaluating {sup d}ecrease in secondary heat removal{sup e}vents such as Loss of Normal Feedwater accident. To demonstrate optimum pressurizer level setpoint, RETRAN-03 code is used for performance analysis. Analysis results of RETRAN following reactor trip are compared with the actual plant data to justify RETRAN code modelling. The results of performance and safety analyses show that the newly established level setpoints not only improve the performance of pressurizer during transient including reactor trip but also meet the design bases of the pressurizer volume and pressure. 6 refs., 5 figs. (Author)

  5. Traditional Periodization versus Optimum Training Load Applied to Soccer Players: Effects on Neuromuscular Abilities.

    Science.gov (United States)

    Loturco, I; Nakamura, F Y; Kobal, R; Gil, S; Pivetti, B; Pereira, L A; Roschel, H

    2016-12-01

    It is unknown whether traditional periodization of strength-power training involving accumulation, transformation and realization blocks is superior to other simpler and more practical training schemes. The purpose of this study was thus to investigate changes in strength/power/speed characteristics of elite soccer players in response to either classic strength-power periodization (TSP) or optimum power load (OPL). 23 professional soccer players were randomly assigned to TSP or OPL for 6 weeks in-season regular training (3 times per week). TSP involved half squats or jump squats, depending on the respective training block, while OPL involved only jump squats at the optimum power load. Results revealed that both groups presented similar significant (Psuperior effect of OPL to improve 10- and 20-m speed. Similarly, OPL presented greater delta change in mean propulsive power in the jump squat. Therefore, training continuously at the optimum power zone resulted in superior performance improvements compared to training under classic strength-power periodization. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Comparative study of decay ratios of disturbance-rejection magnitude optimum method for PI controllers.

    Science.gov (United States)

    Lumbar, Satja; Vrancić, Damir; Strmcnik, Stanko

    2008-01-01

    One of the key time-domain closed-loop performance requirements is the closed-loop response decay ratio. In this paper, the decay ratios of the disturbance-rejection magnitude optimum (DRMO) tuning method [Vrancić D, Strmcnik S, Kocijan J. Improving disturbance rejection of PI controllers by means of the magnitude optimum method. ISA Trans 2004; 43: 73-84; Vrancić D, Strmcnik S. Achieving optimal disturbance rejection by using the magnitude optimum method. In: Pre-prints of the CSCC'99 conference. 1999. p. 3401-6] are analyzed and compared to decay ratios of two other modern tuning methods, i.e. the Kappa-Tau tuning method (based on time-domain step-response characteristics) [Aström KJ, Högglund T. PID controllers: Theory, design, and tuning. 2nd ed. Instrument Society of America; 1995] and the non-convex optimization tuning method (based on frequency response) [Panagopoulos H, Aström KJ, Hägglund T. Design of PI controllers based on non-convex optimization. Automatica 1998; 34: 585-601; Panagopoulos H, Aström KJ, Hägglund T. Design of PID controllers based on constrained optimisation. IEE Proc Control Theory Appl 2002; 149 (1): 32-40]. It is shown that the DRMO method results in such a closed-loop response that the decay ratio is within a relatively narrow interval when compared to the other two methods.

  7. CSR organisational taxonomy and job characteristics on performance: SME case studies

    Directory of Open Access Journals (Sweden)

    Thanalechumy Seeramulu

    2017-05-01

    Full Text Available This study examines the relationship between the CSR of organizational structure and job characteristics that influence employee job performance in the Malaysian context. Hence, it is important to study and analyze these two factors within the CSR taxonomy describing how these factors significantly influence employee job performance and to make recommendations how performance can be promoted among employees. This paper is based on a quantitative research approach where responses were gathered from the working population within Malaysia SMEs. The results from this study will help to point out the influence of these factors on the employee job performance and provide guidance to an organization for which these aspects should be emphasized in order to increase employees’ job performance to align performance with organizational goals. The analysis includes two dimensions of CSR taxonomy of organizational structure namely, centralization and formalization, as well as a set of five dimensions of job characteristics, such as task identity, task significance, skill variety, autonomy and feedback. The results of these findings show that job characteristics such as task significance, autonomy, feedback, and skill variety, positively influence job performance with autonomy having highest predictive power on job performance. The results of these findings reveal that the organizational structure does not contribute to the prediction of job performance even though a significant positive correlation exists between the structure and job performance in the Pearson correlation coefficient test. Therefore, this study will enrich the existing knowledge in the area of human resource management by focusing on job performance management.

  8. MAXIMUM INFORMATION AND OPTIMUM ESTIMATING FUNCTION

    Institute of Scientific and Technical Information of China (English)

    林路

    2003-01-01

    In order to construct estimating functions in some parametric models, this paper introducestwo classes of information matrices. Some necessary and sufficient conditions for the informationmatrices achieving their upper bounds are given. For the problem of estimating the median,some optimum estimating functions based on the information matrices are acquired. Undersome regularity conditions, an approach to carrying out the best basis function is introduced. Innonlinear regression models, an optimum estimating function based on the information matricesis obtained. Some examples are given to illustrate the results. Finally, the concept of optimumestimating function and the methods of constructing optimum estimating function are developedin more general statistical models.

  9. Relationship of Student Characteristics and Performance in a Personalized System of Instruction Course.

    Science.gov (United States)

    Roberts, Michael C.; And Others

    1978-01-01

    The author examined college student characteristics and their relation to performance in a psychology course which employed a personalized system of instruction (PSI). Findings indicated that dependable predictors, such as past performance and ability measures, were as applicable to PSI courses as to traditional ones. (Author/DB)

  10. How stem defects affect the capability of optimum bucking method?

    Directory of Open Access Journals (Sweden)

    Abdullah Emin Akay

    2015-07-01

    Full Text Available In forest harvesting activities, computer-assisted optimum bucking method increases the economic value of harvested trees. The bucking decision highly depends on the log quality grades which mainly vary with the surface characteristics such as stem defects and form of the stems. In this study, the effects of stem defects on optimum bucking method was investigated by comparing bucking applications which were conducted during the logging operations in two different Brutian Pine (Pinus brutia Ten stands. In the applications, the first stand contained the stems with relatively more stem defects than that of the stems in the second stand. The average number of defects per log for sample trees in the first and the second stand was recorded as 3.64 and 2.70, respectively. The results indicated that optimum bucking method increased the average economic value of harvested trees by 15.45% and 8.26 % in the stands, respectively. Therefore, the computer-assisted optimum bucking method potentially provides better results than that of traditional bucking method especially for the harvested trees with more stem defects.

  11. A Study of the Associations between Conditions of Performance and Characteristics of Performers and New York State Solo Performance Ratings

    Science.gov (United States)

    vonWurmb, Elizabeth C.

    2013-01-01

    This dissertation undertakes an analysis of 1,044 performance evaluations from New York State School Music Association (NYSSMA) Spring Festival solo adjudication ratings of student performers from a large suburban school district. It relies on results of evaluations of observed performances, and takes these evaluations as assessments of what the…

  12. NOAA Optimum Interpolation (OI) SST V2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST's plus...

  13. Optimum Pipe Size Selection for Turbulent Flow

    Directory of Open Access Journals (Sweden)

    Timothy A. AKINTOLA

    2009-07-01

    Full Text Available Pipelines are normally designed to deliver fluid at the required head and flow rate in a cost effective manner. Increase in conduit diameter leads to increase in annual capital costs, and decrease in operating costs. Selection of an optimum conduit diameter for a particular fluid flow will therefore be a vital economic decision. This paper presents a computer aided optimisation technique for determination of optimum pipe diameter for a number of idealized turbulent flow. Relationships were formulated connecting theories of turbulent fluid flow with pipeline costing. These were developed into a computer program, written in Microsoft Visual C++ language, for a high-level precision estimate of the optimum pipe diameter, through the least total cost approach. The validity of the program was ascertained through case studies, representative of fluids with different densities and compressibility. The optimum conduit diameter was found to increase linearly with increase in compressibility.

  14. Construction Professionals Job Performance and Characteristics: A Comparison of Indigenous and Expatriate Construction Companies in Nigeria

    Directory of Open Access Journals (Sweden)

    Henry Ndubuisi Onukwube

    2011-06-01

    Job performance is considered one of the most important constructs in human resources management because it helps to explain the value and utility that each employee adds to the organisation. The professionals in the Nigerian construction companies are not exception to the perceived low job performance rate within the industry. Extant literature points to the fact that job characteristics of employees can account for variance in their job performance rate.This study compares the job performance rate and job characteristics of construction professionals in indigenous and expatriate construction companies with a view to establish a relationship between job performance and job characteristics of construction professionals. A total of 762 questionnaires were collected and used for the study.  Eighty one (81 construction companies, 50 (62% indigenous and 31 (38% expatriate were selected using stratified random sampling technique. Data collected were analysed using mean item score, spearman rank correlation, linear regression analysis where appropriate. Findings of the study revealed that the relationship between job characteristics and job performance of construction professionals in construction companies in Nigeria is positive but low and the correlation coefficient is higher in expatriate construction companies. Based on the above finding, the study recommends that construction companies in Nigeria should endeavour and improve on their current core job dimensions (task significance, skill variety, task identity, autonomy and feedback inherent in various jobs designed within their respective organizations as this will constitute as one of the variants that will improve the job performance rate of construction professionals.

  15. On Optimum Causal Cognitive Spectrum Reutilization Strategy

    CERN Document Server

    Haghighi, Kasra; Agrell, Erik

    2011-01-01

    In this paper we study opportunistic transmission strategies for cognitive radios (CR) in which causal noisy observation from a primary user(s) (PU) state is available. PU is assumed to be operating in a slotted manner, according to a two-state Markov model. The objective is to maximize utilization ratio (UR), i.e., relative number of the PU-idle slots that are used by CR, subject to interference ratio (IR), i.e., relative number of the PU-active slots that are used by CR, below a certain level. We introduce an a-posteriori LLR-based cognitive transmission strategy and show that this strategy is optimum in the sense of maximizing UR given a certain maximum allowed IR. Two methods for calculating threshold for this strategy in practical situations are presented. One of them performs well in higher SNRs but might have too large IR at low SNRs and low PU activity levels, and the other is proven to never violate the allowed IR at the price of a reduced UR. In addition, an upper-bound for the UR of any CR strategy...

  16. Effects of various dietary lipid additives on lamb performance, carcass characteristics, adipose tissue fatty acid composition, and wool characteristics.

    Science.gov (United States)

    Meale, S J; Chaves, A V; He, M L; Guan, L L; McAllister, T A

    2015-06-01

    Tasco (Ascophyllum nodosum; TA) was compared to canola (CO), flax (FO), and safflower oils (SO) for effects on performance, carcass characteristics, and fatty acid profiles of adipose tissue in skirt muscle (SM), subcutaneous and perirenal adipose tissues, and wool production and quality characteristics of Canadian Arcott lambs. Fifty-six lambs were randomly assigned to dietary treatments (n = 14 per treatment). Diets consisted of a pelleted, barley-based finishing diet containing either TA, CO, FO, or SO (2% of dietary DM). Feed deliveries and orts were recorded daily. Lambs were weighed weekly and slaughtered once they reached ≥ 45 kg BW. Carcass characteristics, rumen pH, and liver weights were determined at slaughter. Wool yield was determined on mid-side patches of 100 cm2 shorn at d 0 and on the day before slaughter (d 105 or 140). Dye-bands were used to determine wool growth, micrometer and staple length. Adipose tissues and SM samples were taken at slaughter and analyzed for FA profiles. No effects were observed on intake, growth, or carcass characteristics. A greater (P = 0.02) staple strength of lambs fed CO was the only effect observed in wool. Flax oil increased total n-3 and decreased the n-6/n-3 ratio in tissue FA profiles (P < 0.001) in comparison to other diets. Tasco increased (P ≤ 0.001) SFA/PUFA in all tissues, whereas concentrations of CLA c-9, t-11 were greatest with SO in all tissues (P ≤ 0.02), compared to other diets. These results suggest Tasco supplementation did not improve the n-3/n-6 or SFA/PUFA ratios of lamb adipose tissues compared to other dietary lipid additives.

  17. Comparison of fattening performance, carcass characteristics, and egg quality characteristics of Japanese quails with different feather colors

    Directory of Open Access Journals (Sweden)

    Hakan Inci

    2015-11-01

    Full Text Available The objective of this study was to compare fattening performance, carcass traits, and egg quality of Japanese quails with different feather colors (white, dark brown, golden, and wild-type. In the study, 360 one-day-old quail chicks with 4 different feather colors were used as animal material. Quails were fed ad libitum for 42 days to determine fattening performance and carcass traits. To determine egg traits, 48 hens from each group, in a total of 192, were selected and caged according to feather color. Eggs were collected for four consecutive weeks and egg quality characteristics were measured. Different feather colors had a significant effect on live weight, feed intake, feed conversion ratio, and carcass characteristics. Significant differences between the groups were detected for egg weight, specific gravity, shape index, shell weight, albumen weight, yolk weight, albumen index, and yolk index. Japanese quails with all four feather colors can be reared depending on the choice. However, due to lower feed conversion ratio, white-feathered quails may be preferred for meat production purposes. Color variations should be considered when selecting quails.

  18. Performance characteristics of LOX-H2, tangential-entry, swirl-coaxial, rocket injectors

    Science.gov (United States)

    Howell, Doug; Petersen, Eric; Clark, Jim

    1993-01-01

    Development of a high performing swirl-coaxial injector requires an understanding of fundamental performance characteristics. This paper addresses the findings of studies on cold flow atomic characterizations which provided information on the influence of fluid properties and element operating conditions on the produced droplet sprays. These findings are applied to actual rocket conditions. The performance characteristics of swirl-coaxial injection elements under multi-element hot-fire conditions were obtained by analysis of combustion performance data from three separate test series. The injection elements are described and test results are analyzed using multi-variable linear regression. A direct comparison of test results indicated that reduced fuel injection velocity improved injection element performance through improved propellant mixing.

  19. Optimum primary and supplementary signals optimizing the seismic data resolution

    Science.gov (United States)

    Tyapkin, Yuriy K.

    2001-03-01

    Often in practice, when generating seismic waves on a line, even with a wide-band source, numerous natural and technical obstacles cause a low resolution of reflection seismograms. In this case, the economy of the survey should be taken into consideration and rather than ignoring preexisting data, generating additional signal to complement the preexisting data should be tried. This paper describes how this can be done to optimize the resolution of the combined data. The new approach requires a fundamental change in the field technique such that records with different spectral characteristics (RDSC) are now generated from each source-receiver pair. These coincident records share a common reflectivity series, but differ from each other in wavelets and noise. A comprehensive theory for optimum processing (deconvolution) of any available suite of the RDSC is developed. The solution for the problem is a particular case of multichannel Wiener filtering. It can be thought of as two successive procedures. The first is optimum frequency-dependent weighted stacking of the RDSC. The second is single-channel zero-phase Wiener deconvolution filtering of the previous output. This representation enables suggested multichannel filtering to be easily implemented. The effectiveness of the method as well as its advantage over straight summing of the RDSC, followed by single-channel Wiener deconvolution filtering, are corroborated theoretically and demonstrated with field data. Furthermore, a solution is suggested for the problem to evaluate the spectrum of an optimum supplementary signal. The signal contributes to the available set of the RDSC and yields either maximum resolution with limited energy expenses or a certain desired resolution with minimum, but unrestricted energy expenses at the output of the optimum procedure. The optimum distribution of the spectral energy of a primary signal along the frequency axis is a particular case of the above problem with no preexisting data.

  20. Optimum profit model considering production, quality and sale problem

    Science.gov (United States)

    Chen, Chung-Ho; Lu, Chih-Lun

    2011-12-01

    Chen and Liu ['Procurement Strategies in the Presence of the Spot Market-an Analytical Framework', Production Planning and Control, 18, 297-309] presented the optimum profit model between the producers and the purchasers for the supply chain system with a pure procurement policy. However, their model with a simple manufacturing cost did not consider the used cost of the customer. In this study, the modified Chen and Liu's model will be addressed for determining the optimum product and process parameters. The authors propose a modified Chen and Liu's model under the two-stage screening procedure. The surrogate variable having a high correlation with the measurable quality characteristic will be directly measured in the first stage. The measurable quality characteristic will be directly measured in the second stage when the product decision cannot be determined in the first stage. The used cost of the customer will be measured by adopting Taguchi's quadratic quality loss function. The optimum purchaser's order quantity, the producer's product price and the process quality level will be jointly determined by maximising the expected profit between them.

  1. A scheme for assessing the performance characteristics of small field-of-view gamma cameras.

    Science.gov (United States)

    Bhatia, B S; Bugby, S L; Lees, J E; Perkins, A C

    2015-02-01

    Existing protocols for assessing the performance characteristics of large field-of-view (LFOV) gamma cameras can be inappropriate and require modification for use with small field-of-view (SFOV) gamma camera systems. This communication proposes a generic scheme suitable for evaluating the performance characteristics of SFOV gamma cameras, based on modifications to the standard procedures of NEMA NU1-2007. Key differences in methodology between tests for LFOV and SFOV gamma cameras are highlighted along with the rationale for these changes. It is envisaged that this scheme will provide more appropriate methods for equipment characterisation, ensuring quality and consistency for all SFOV cameras.

  2. Performance characteristics of low-dissipative generalized Carnot cycles with external leakage losses

    Institute of Scientific and Technical Information of China (English)

    黄传昆; 郭君诚; 陈金灿

    2015-01-01

    Under the assumption of low-dissipation, a unified model of generalized Carnot cycles with external leakage losses is established. Analytical expressions for the power output and efficiency are derived. The general performance characteristics between the power output and the efficiency are revealed. The maximum power output and efficiency are calculated. The lower and upper bounds of the efficiency at the maximum power output are determined. The results obtained here are universal and can be directly used to reveal the performance characteristics of different Carnot cycles, such as Carnot heat engines, Carnot-like heat engines, flux flow engines, gravitational engines, chemical engines, two-level quantum engines, etc.

  3. Development of FEC and ESC performance characteristics for IDR carriers greater than 10 Mb/s

    Science.gov (United States)

    Loureiro, Francisco; Koga, Keiichiro

    1988-12-01

    The requirement for restoration of high capacity fiber optic cables and the new tariffs approved for Intelsat digital services has created a requirement to develop performance characteristics for intermediate data rate (IDR) carriers greater than 10 Mb/s. This paper presents the trade-offs used in this development, and estimates the coding gains needed to meet these requirements. A number of forward error correction schemes are evaluated and a rate 3/4 convolutional code with soft decision Viterbi decoding is selected. Engineering service circuits performance characteristics for IDR carriers greater than 10 Mb/s are presented.

  4. Optimization of Performance Characteristics of Hybrid Wind Photovoltaic System with Battery Storage

    Directory of Open Access Journals (Sweden)

    C. Kathirvel

    2014-03-01

    Full Text Available This study concentrates on the Design and Implementation of a multi source hybrid Wind-Photovoltaic stand alone system with proposed energy management strategy. The method of investigation concerned with the definition of the system topology, interconnection of the various sources with maximum energy transfer, optimum control and energy management in order to maintain the DC bus voltage into a fixed value. An Energy management strategy was proposed using the Fuzzy logic controller such that enhancement in the performance of the system and optimization can be done. The Fuzzy logic controller takes the input from Solar (irradiation, Wind (speed, Power demand and the battery voltage which controls the respective subsystem and formulates into different operational modes of energy management. The role of Fuzzy threshold controller is to adjust continuously the threshold value for optimal performance based on expected wind, solar conditions, battery voltage and power demand. It is shown that when the fuzzy logic controller is used, the proposed DC bus voltage regulation strategy with different modes of operation have fast response and efficient operation which leads to a reduced operating cost.

  5. Performance and heat transfer characteristics of HFC-134a and CFC-12 in a water chiller

    Energy Technology Data Exchange (ETDEWEB)

    Devotta, S.; Parande, M.G.; Patwardhan, V.R. [National Chemical Lab., Pune (India)

    1998-07-01

    A water chiller with an open reciprocating compressor has been used to comparatively assess the performance of HFC-134a with reference to CFC-12 under as close to identical conditions as possible. Performance characteristics of the chiller under retrofit conditions show that HFC-134a offers better cooling load and coefficients of performance vis-a-vis CFC-12 for identical operating conditions. Further heat transfer analysis of data for the condenser shows that the condensing heat transfer coefficients for HFC-134a are superior to CFC-12. The better performance of HFC-134a may be ascribed to the better heat transfer coefficient of HFC-134a over CFC-12. (Author)

  6. Performance Characteristic of Cold Recycled Mixture with Asphalt Emulsion and Chemical Additives

    Directory of Open Access Journals (Sweden)

    Shaowen Du

    2015-01-01

    Full Text Available Three types of chemical additives were used to modify asphalt emulsion recycled mixture. These chemical additives include composite Portland cement (CPC, hydrated lime (HL, and a combination of hydrated lime and ground-granulated blast-furnace slag (GGBF. The influence of different additives on the recycled mixture performance was investigated by volumetric and strength tests, moisture susceptibility test, rutting resistance test, and low temperature bending test. To better understand its performance characteristic, the microstructure images of the recycled mixture were observed by environmental scanning electron microscope (ESEM. Test results demonstrate that the performance improvement of the emulsion recycled mixture depends on the types and content of chemical additives. Several recommendations are presented for the selection of chemical materials. Based on ESEM image analysis, the interface bonding mechanism is proposed to explain the performance characteristic of the recycled mixture with asphalt emulsion and cementitious materials.

  7. Managerial Characteristics and its Impact on Organizational Performance: Evidence from Syria

    Directory of Open Access Journals (Sweden)

    Elias Milana

    2015-06-01

    Full Text Available This study aims to explore impact of managerial human capital in performance of a Syrian public organization, Directorate of Finance of province of Damascus, through use some of managerial characteristics are age, level of education, tenure and functional track. This study applied on a sample of 12 managers and 138 employees. The study reveals that there are no significant effect of age, level of education and functional track in performance of Directorate of Finance of province of Damascus, while there is a positive, strong and significant effect of tenure manager in organizational performance, which indicates that managerial characteristics almost irrelevant with performance of Directorate of Finance of the province of Damascus, and the public sector in general. Such results appear a need for efforts are invested in the formulation and implementation of human resource procedures and policies which can bring about effective change in behaviours and roles of the public managers and employees.

  8. Using anthropometric and performance characteristics to predict selection in junior UK Rugby League players.

    Science.gov (United States)

    Till, Kevin; Cobley, Steve; O'Hara, John; Brightmore, Amy; Cooke, Carlton; Chapman, Chris

    2011-05-01

    Research examining the factors influencing selection within talented junior Rugby League players is limited. The aims of this study were firstly to determine whether differences existed for anthropometric and performance characteristics between regional and national selection in high performance UK junior Rugby League players, and secondly to identify variables that discriminated between these selection levels. Regional representative (n=1172) selected junior players (aged 13-16 years) undertook an anthropometric and fitness testing battery with players split according to selection level (i.e., national, regional). MANCOVA analyses, with age and maturation controlled, identified national players as having lower sum of 4 skinfolds scores compared to regional players, and also performed significantly better on all physical tests. Stepwise discriminant analysis identified that estimated maximum oxygen uptake (VO2max), chronological age, body mass, 20 m sprint, height, sum of 4 skinfolds and sitting height discriminated between selection levels, accounting for 28.7% of the variance. This discriminant analysis corresponded to an overall predictive accuracy of 63.3% for all players. These results indicate that performance characteristics differed between selection levels in junior Rugby League players. However, the small magnitude of difference between selection levels suggests that physical qualities only partially explain higher representative selection. The monitoring and evaluation of such variables, alongside game related performance characteristics, provides greater knowledge and understanding about the processes and consequences of selection, training and performance in youth sport. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  9. Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study

    Science.gov (United States)

    Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian

    2016-01-01

    This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…

  10. A Report on the Performance Characteristics of Power Sources for Remote Areas

    Science.gov (United States)

    This report summarizes performance characteristics of candidate power sources planned particularly for use by indigenous forces of friendly...underdeveloped nations. Older types of power sources , such as heat engines, hydroelectric and magnetohydrodynamic, are suggested for continued research and...summarizes in detail the status of technologic development of power sources is included.

  11. Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study

    Science.gov (United States)

    Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian

    2016-01-01

    This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…

  12. Students' Psychosocial Characteristics as Predictors of Academic Performance in Medical School.

    Science.gov (United States)

    Hojat, Mahammadreza; And Others

    1993-01-01

    A study of 175 Jefferson Medical College (Pennsylvania) students compared psychosocial characteristics with basic science examination grades, clinical examination grades, and ratings of clinical competence as performance measures. Results indicate the noncognitive psychosocial measures are significant and unique predictors of medical school…

  13. Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs

    NARCIS (Netherlands)

    Sterk, A.R.; Schlegel, P.; Mul, A.J.; Ubbink-Blanksma, M.; Bruininx, E.M.A.M.

    2008-01-01

    To assess the effects of 2 high intensity sodium saccharine based sweeteners on individual feed intake characteristics and performance of group-housed weaned pigs, 198 26-d-old weanling pigs were given ad libitum access to 3 dietary treatments: containing no additional sweetener (Control), 150 mg sw

  14. Physico Chemical Characteristics of High Performance Polymer Modified by Low and Atmospheric Pressure Plasma1

    NARCIS (Netherlands)

    Bhatnagar, N.; Jha, S.; Bhowmik, S.; Gupta, G.; Moon, J.B.; Kim, C.G.

    2012-01-01

    In this work, the effect of low pressure plasma and atmospheric-pressure plasma treatment on surface properties and adhesion characteristics of high performance polymer, Polyether Ether Ketone (PEEK) are investigated in terms of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron

  15. Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs

    NARCIS (Netherlands)

    Sterk, A.R.; Schlegel, P.; Mul, A.J.; Ubbink-Blanksma, M.; Bruininx, E.M.A.M.

    2008-01-01

    To assess the effects of 2 high intensity sodium saccharine based sweeteners on individual feed intake characteristics and performance of group-housed weaned pigs, 198 26-d-old weanling pigs were given ad libitum access to 3 dietary treatments: containing no additional sweetener (Control), 150 mg

  16. Performance Characteristics of Long-Track Speed Skaters : A Literature Review

    NARCIS (Netherlands)

    Konings, Marco J.; Elferink-Gemser, Marije T.; Stoter, Inge K.; van der Meer, Dirk; Otten, Egbert; Hettinga, Florentina J.

    2015-01-01

    Speed skating is an intriguing sport to study from different perspectives due to the peculiar way of motion and the multiple determinants for performance. This review aimed to identify what is known on (long-track) speed skating, and which individual characteristics determine speed skating performan

  17. Hindi Heritage Language Learners' Performance during OPIs: Characteristics and Pedagogical Implications

    Science.gov (United States)

    Ilieva, Gabriela Nik.

    2012-01-01

    The present paper examines the oral performance of Hindi language learners during practice Oral Proficiency Interviews (OPI) conducted during workshops hosted by New York University and sponsored by STARTALK. The most salient characteristics of the heritage language learners' output are compared with the output of foreign language learners who are…

  18. Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

    Science.gov (United States)

    Cowen, Brandon; Stringer, Mary T.; Hutchinson, Brian K.; Davidson, Paul C.; Gupton, Lawrence E.

    2014-01-01

    This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the Cockpit Motion Facility (CMF) will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law.

  19. Optimum sensitivity derivatives of objective functions in nonlinear programming

    Science.gov (United States)

    Barthelemy, J.-F. M.; Sobieszczanski-Sobieski, J.

    1983-01-01

    The feasibility of eliminating second derivatives from the input of optimum sensitivity analyses of optimization problems is demonstrated. This elimination restricts the sensitivity analysis to the first-order sensitivity derivatives of the objective function. It is also shown that when a complete first-order sensitivity analysis is performed, second-order sensitivity derivatives of the objective function are available at little additional cost. An expression is derived whose application to linear programming is presented.

  20. Method for Determining Optimum Injector Inlet Geometry

    Science.gov (United States)

    Trinh, Huu P. (Inventor); Myers, W. Neill (Inventor)

    2015-01-01

    A method for determining the optimum inlet geometry of a liquid rocket engine swirl injector includes obtaining a throttleable level phase value, volume flow rate, chamber pressure, liquid propellant density, inlet injector pressure, desired target spray angle and desired target optimum delta pressure value between an inlet and a chamber for a plurality of engine stages. The method calculates the tangential inlet area for each throttleable stage. The method also uses correlation between the tangential inlet areas and delta pressure values to calculate the spring displacement and variable inlet geometry of a liquid rocket engine swirl injector.

  1. Optimum PN Guidance Law for Maneuvering Target

    Institute of Scientific and Technical Information of China (English)

    SUN Bao-cai; QI Zai-kang

    2007-01-01

    An optimum PN guidance law for maneuvering target is developed using optimal control theory. By estimating the target position and setting the cost function, the guidance law can be deduced even without knowing the missile lateral acceleration. Since the quadratic cost function can make a compromise between the miss distance andthe control constraint, the optimum guidance law obtained is more general. Also, introduced line of sight rate as the input, a practical form of this guidance law is derived. The simulation results show the effectiveness of the guidance laws.

  2. Application of desirability function for optimizing the performance characteristics of carbonitrided bushes

    Directory of Open Access Journals (Sweden)

    Boby John

    2013-06-01

    Full Text Available The performance of a product is generally characterized by more than one response variable. Hence the management often faces the problem of simultaneous optimization of many response variables. This study was undertaken to simultaneously optimize the surface hardness and case depth of carbonitrided bushes. Even though lots of literature has been published on various methodologies for tackling the multi-response optimization problem, the simultaneous optimization of heat treated properties of carbonitrided bushes are not reported yet. In this research the effect of four factors and two interactions on surface hardness and case depth of carbontirded bushes were studied using design of experiments. Based on the experimental results, the expected values of the heat treated properties of the bushes were estimated for all possible combination of factors. Then the best combination which, simultaneously optimized the response variables, was arrived at using desirability function. The study showed that the optimum combination obtained through desirability function approach not only minimized the variation around the targets of surface hardness and case depth but also was superior to the ones obtained by optimizing the response variables separately. Moreover this study provides a useful and effective approach to design the production process to manufacture bushes with customer specified surface hardness and case depth targets.

  3. A study on the performance and emission characteristics of esterified pinnai oil tested in VCR engine.

    Science.gov (United States)

    Ashok Kumar, T; Chandramouli, R; Mohanraj, T

    2015-11-01

    Biodiesel is a clean renewable fuel derived from vegetable oils and animal fats. It is biodegradable, oxygenated, non toxic and free from sulfur and aromatics. The biodiesel prepared from pinnai oil undergoes acid esterification followed by alkaline transesterification process. The fatty acid methyl esters components were identified using gas chromatography and compared with the standard properties. The properties of biodiesel are comparable with diesel. The yield of the biodiesel production depends upon the process parameters such as reaction temperature, pH, time duration and amount of catalyst. The yield of biodiesel by transesterification process was 73% at 55°C. This fuel was tested in a variable compression ratio engine with blend ratios of B10 and B20. During the test runs the compression ratio of the engine was varied from 15:1 to 18:1 and the torque is adjusted from zero to maximum value of 22Nm. The performance characteristics such as the brake thermal efficiency, brake specific energy consumption and exhaust gas temperature of the engine are analyzed. The combustion characteristics of biodiesel like ignition delay, combustion duration and maximum gas temperature and the emission characteristics are also analyzed. The performance characteristics, combustion characteristics and engine emission are effective in the variable compression ratio engine with biodiesel and it is compared with diesel.

  4. Performance characteristics of turbo blower in a refuse collecting system according to operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jang, C. M.; Kim, D. W. [Korea Institute of Construction Technology, Goyang (Korea, Republic of); Lee, S. Y. [ANST, Seoul (Korea, Republic of)

    2008-10-15

    A simulator for a refuse collecting system is designed to investigate the performance characteristics of a turbo blower operating at different rotational frequencies. The simulator consists of an air intake, a waste chute, circular duct, waste collector and turbo blower. Experimental measurements and numerical simulation with three-dimensional Navier- Stokes equations have been performed to analyze the performance of the turbo blower. Throughout numerical simulation of the simulator, it is found that the input energy of the blower can be reduced by controlling the rotational frequency of impeller while the efficiency of the blower keeps constant. The required outlet pressure and flow rate of the blower can be also adjusted along the system resistance of the refuse collecting system. Detailed flow characteristics inside the blower are analyzed for different rotational frequencies

  5. The Thermal Performance and Air Leakage Characteristics of Six Log Homes in Idaho.

    Energy Technology Data Exchange (ETDEWEB)

    Roos, Carolyn; Eklund, Ken; Baylon, David

    1993-08-01

    The thermal performance and air leakage characteristics of four electrically heated log houses located in Idaho are summarized. The air leakage and construction characteristics of two additional log homes are also examined. The energy consumption of the four homes was submetered at weekly reporting intervals for up to 16 months. Blower door tests and site audits were performed. In addition, conditions at two of these homes, including heat flux through the log walls, indoor and outdoor temperatures, solar flux and envelope tightness, were measured in detail over several days during winter conditions. The energy use and thermal performance of these two homes were then modeled using SUNCODE-PC, an hourly thermal simulation program employing a finite difference technique.

  6. Board characteristics, governance objectives, and hospital performance: An empirical analysis of German hospitals.

    Science.gov (United States)

    Thiel, Andrea; Winter, Vera; Büchner, Vera Antonia

    2017-02-02

    There is a growing need for hospital supervisory boards to support hospital management in different areas, including (financial) monitoring, resource provision, stakeholder relationships, and strategic decision-making. Little is currently known about how boards' emphases on these various governance objectives contribute to performance. Using a dominant logics perspective, this article aims to detect the governance logics that hospital boards emphasize, to determine whether there are distinct clusters of hospitals with the same sets of emphases, and to show how cluster membership relates to board characteristics and financial performance. Using factor analysis, we identify latent classes of governance objectives and use hierarchical cluster analysis to detect distinct clusters with varying emphasis on the classes. We then use multinomial regression to explore the associations between cluster membership and board characteristics (size, gender diversity, and occupational diversity) and examine the associations between clusters and financial performance using OLS regression. Classes of objectives reflecting three governance theories-agency theory, stewardship theory, and stakeholder theory-can be distinguished, and hospitals can be divided into four clusters based on their board's relative emphasis on the classes. Cluster membership is significantly associated with board characteristics. There is also a significant association between cluster membership and hospital financial performance, with two of three groups performing significantly better than the reference group. High performance in hospitals can be the result of governance logics, which, compared to simple board characteristics, are associated with better financial outcomes. Hospitals can influence the emphasis placed on different governance objectives and enhance organizational success by creating boards that are small enough to be effective yet diverse enough to profit from a wide variety of expertise and

  7. Observed inter-camera variability of clinically relevant performance characteristics for Siemens Symbia gamma cameras.

    Science.gov (United States)

    Kappadath, S Cheenu; Erwin, William D; Wendt, Richard E

    2006-11-28

    We conducted an evaluation of the intercamera (i.e., between cameras) variability in clinically relevant performance characteristics for Symbia gamma cameras (Siemens Medical Solutions, Malvern, PA) based on measurements made using nine separate systems. The significance of the observed intercamera variability was determined by comparing it to the intracamera (i.e., within a single camera) variability. Measurements of performance characteristics were based on the standards of the National Electrical Manufacturers Association and reports 6, 9, 22, and 52 from the American Association of Physicists in Medicine. All measurements were performed using 99mTc (except 57Co used for extrinsic resolution) and low-energy, high-resolution collimation. Of the nine cameras, four have crystals 3/8 in. thick and five have crystals 5/8 in. thick. We evaluated intrinsic energy resolution, intrinsic and extrinsic spatial resolution, intrinsic integral and differential flood uniformity over the useful field-of-view, count rate at 20% count loss, planar sensitivity, single-photon emission computed tomography (SPECT) resolution, and SPECT integral uniformity. The intracamera variability was estimated by repeated measurements of the performance characteristics on a single system. The significance of the observed intercamera variability was evaluated using the two-tailed F distribution. The planar sensitivity of the gamma cameras tested was found be variable at the 99.8% confidence level for both the 3/8-in. and 5/8-in. crystal systems. The integral uniformity and energy resolution were found to be variable only for the 5/8-in. crystal systems at the 98% and 90% confidence level, respectively. All other performance characteristics tested exhibited no significant variability between camera systems. The measured variability reported here could perhaps be used to define nominal performance values of Symbia gamma cameras for planar and SPECT imaging.

  8. Geographic variation and genetic performance of Picea koraiensis in growth and wood characteristics

    Institute of Scientific and Technical Information of China (English)

    WANGQiu-yu; JIAHong-bai; SHANGJie

    2005-01-01

    Eight provenances of 19-year-old Picea koraiensis Nakai from the provenance trials of Maoershan (45°20'N, 127°30'E), Liangeshui (47°10'N, 128°53'E) and Jiagedaqi (50°24'N, 124°07'E) in Northeast China were investigated to analyze the genetic variation in growth characteristics (tree height and diameter) and wood characteristics (tracheid length, tracheid diameter, tracheid wall thickness, annual ring width as well as wood density). Great variation in height growth and breast height diameter growth was observed among the provenances,and along with the increase of tree age, these provenances presented different geographic adaptability. The growth characteristics of Picea koraiensis stand at age of 10 in Maoershan and Liangshui provenance trials had a positive correlation with longitude, and with increase of tree age to 15 and 19, the tree growth of the provenances displayed a significant positive correlation with latitude as well as altitude. For wood characteristics, great variation was also found among the provenances. There exists a close relation between growth characteristics and wood properties of the provenance. The height and breast height diameter growth of the provenance had a positive correlation with tracheid diameter and annual ring width, and a negative correlation with tracheid wall thickness and wood density. Genetic performance of the provenance in all above characteristics was also investigated in order to provide more useful information for comprehensive selection of this species for pulpwood and plywood production.

  9. The effect of management team characteristics on performance and style extremity of mutual fund portfolios

    Directory of Open Access Journals (Sweden)

    Liu Qiong

    2014-01-01

    Full Text Available Purpose: Along with mutual funds’ scale and quantity expanding for our country, it is common for fund management companies hiring new managers or the original fund managers mobilizing from one to another. The high liquidity of fund managers makes different managers regroup to manage the funds that belong to the same fund management company in each fund year. The characteristics of these different management team will influence the fund performance, and also affect the earnings of the fund management company and portfolio investors. The purpose of this paper is as follows. First, evaluating the effect of management team characteristics on portfolio characteristics: risk, performance, and extremity. Second, testing the hypothesis that the ranking of mid-year performance have effect on investment style extremity and research what relationship exists between this phenomenon and management team characteristics in depth.Design/methodology/approach: On the analysis of the relationships between the management team characteristics and portfolio characteristics, a series of OLS regressions is run where the time series regression model (the factor model and cross-sectional regression are included based on using the STATA, EVIEWS and MATLAB. The validity and practicability of the model will be verified in the paper. All of the above are aimed at achieving portfolio optimization and realizing the maximization of the interests of fund management companies and investors.Findings: The main findings are as follows. Teams with more doctors or MBA (CPA and CFA hold more risky portfolios, while teams with long team tenure hold less. More members and large gender diversity have negative effect on performance, and the opposite is age diversity. Teams with more members and long tenure tend to hold less extreme style decisions, but age diversity is related to more. Besides, tournament hypothesis does exist in China investment funds industry especially when the

  10. ON OPTIMUM DESIGN OF THE SHEARER DRUM

    Institute of Scientific and Technical Information of China (English)

    TaoChidong; ChenChong

    1996-01-01

    On the basis of the model experiments, a software for optimum design of the shearer drum has been developed, and the main parameters of a shearer drum also have been optimized. The combination of the techniques of optimization with the model experiment makes the designing and theoretical systems of the shearer drum more perfect.

  11. Investigation of optimum wavelengths for oximetry

    Science.gov (United States)

    Huong, Audrey K. C.; Stockford, Ian M.; Crowe, John A.; Morgan, Stephen P.

    2009-07-01

    An evaluation of the optimum choice of wavelengths, when using the 'Modified Lambert-Beer law' to estimate blood oxygen saturation, that minimises the mean error across a range of oxygen saturation values is presented. The stability of this approach and its susceptibility to noise are also considered.

  12. Development of the optimum rotor theories

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær; van Kuik, Gijs A.M.

    The purpose of this study is the examination of optimum rotor theories with ideal load distributions along the blades, to analyze some of the underlying ideas and concepts, as well as to illuminate them. The book gives the historical background of the issue and presents the analysis of the proble...

  13. Belichting bromelia: het optimum verschilt per soort

    NARCIS (Netherlands)

    Garcia Victoria, N.; Warmenhoven, M.G.

    2009-01-01

    Het afstemmen van de hoeveelheid assimilatiebelichting en bemesting in de teelt van bromelia's is vakwerk. Extra mest en licht is beter, maar er is een optimum; een plant kan ook te veel mest en licht ontvangen. Voor bepaling van een aangepast teeltrecept is vervolgonderzoek nodig

  14. Common Core: Teaching Optimum Topic Exploration (TOTE)

    Science.gov (United States)

    Karge, Belinda Dunnick; Moore, Roxane Kushner

    2015-01-01

    The Common Core has become a household term and yet many educators do not understand what it means. This article explains the historical perspectives of the Common Core and gives guidance to teachers in application of Teaching Optimum Topic Exploration (TOTE) necessary for full implementation of the Common Core State Standards. An effective…

  15. Minimal Exit Trajectories with Optimum Correctional Manoeuvres

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1980-10-01

    Full Text Available Minimal exit trajectories with optimum correctional manoeuvers to a rocket between two coplaner, noncoaxial elliptic orbits in an inverse square gravitational field have been investigated. Case of trajectories with no correctional manoeuvres has been analysed. In the end minimal exit trajectories through specified orbital terminals are discussed and problem of ref. (2 is derived as a particular case.

  16. Perceptual characteristics of nutritional supplements determine the expected effectiveness in boosting strength, endurance, and concentration performances.

    Science.gov (United States)

    Szabo, Attila; Bérdi, Márk; Köteles, Ferenc; Bárdos, György

    2013-12-01

    The aim of this work was to examine the link between the physical-perceptual characteristics of nutritional supplements and their expected effectiveness in enhancing sport performance. Participants (n = 267) ranked nine images of fictive nutritional supplements, varying in shape, color, and route of administration (e.g., pill, powder, lotion, etc.), in ranked- order of expected effectiveness. They performed the task three times, (1) for strength, (2) endurance, and (3) for concentration. Results have revealed that the perceived effectiveness of the supplements was statistically significantly different for the three types of performances (p nutritional supplements', aimed at sport performance enhancement, influence their perceived effectiveness. Future inquiries in sport nutrition should examine the relationship between expected and experienced effectiveness of various nutritional supplements in enhancing sport performance.

  17. The Effects of Organizational Characteristics on Enterprise Resource Planning Implementation Success and Perceived Organizational Performance

    Directory of Open Access Journals (Sweden)

    Yaşar AKÇA

    2014-06-01

    Full Text Available The aim of this study is to demonstrate the effects of organizational characteristics on Enterprise Resource Planning (ERP system implementation success and organizational performance. For this purpose, data obtained from 236 firms through surveys were analyzed using correlation, factor and regression analysis. The results were as follows; (1 While top management support had a statistically significant and positive effect on ERP implementation success, it had no significant effect on perceived organizational performance. (2 Organizational consensus had a statistically significant effect on neither ERP implementation success nor organizational performance. (3 The effect of training on ERP implementation success and organizational performance was positive. (4 Although information intensity didn’t have an effect on ERP implementation success, it had a statistically significant and positive effect on organizational performance

  18. Crambe meal in supplements for culling cows: animal performance and carcass characteristics

    Directory of Open Access Journals (Sweden)

    Kennyson Alves de Souza

    2015-02-01

    Full Text Available The influence of the replacement of soybean meal by crambe crushed in concentrated supplement at proportions 0, 5, 10, 15%, on the performance and carcass traits of grazing cows is assessed. Within a completely randomized design, twenty Nellore cows, fed on Brachiaria humidicola, were supplemented during the rain-drought transition period and monitored with regard to weight and body conditions every 28 days. Total forage mass and percentages of leaf, stem and senescent material were quantified in loco. The estimation of forage quality consumed by animals was performed by the simulated grazing method. There were no significant differences between the levels of inclusion of crambe crushed on animal performance or carcass characteristics. Replacement did not affect weight, carcass yield, Brazilian commercial cuts, morphometric measures of carcass, characteristics of loins, thickness of carcass fat, perirenal-pelvic fat and total meat. Replacement of soybean meal by crambe crushed up to 15% in the concentrated supplement does not affect performance and carcass characteristics of cows finished on pasture.

  19. How Do Board Characteristics Influence Business Performance? Evidence from Non-life Insurance Firms in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Maxwell Sandada

    2015-08-01

    Full Text Available The purpose of this study was to contribute to the corporate governance literature by establishing the relationship between board characteristics and corporate performance within the nonlife insurance firms in Zimbabwe. The study sought to provide some insights on corporate governance since the phenomenon is relatively an emerging discipline in Zimbabwe. The paper sought to complement other corporate governance studies that were conducted in other environments by producing evidence on the phenomenon from a developing country context. A quantitative research approach was adopted and respondents were selected through a stratified random sampling. The results of the study confirm that board characteristics (board composition, diversity, and size exhibit a statistically significant positive predictive relationship with the performance of non-life insurance firms measured by gross premium written and customer retention. However, CEO/Chairman duality showed a negative relationship with business performance. Non-life insurance companies need to be cognizant of board characteristics in order to improve their performance. Moreover , the findings in this research has practical relevance for the selection process of directors as it highlights the importance of having a sizeable number of board members as well as an appropriate mix of competences and qualifications on the board. Although corporate governance is has been extensively researched, there is limited study in this area from a developing country like Zimbabwe with relatively less developed capital markets. It would be wrong to assume that the findings found in other countries can apply here because the conditions are different.

  20. Reading Traits for Dynamically Presented Texts: Comparison of the Optimum Reading Rates of Dynamic Text Presentation and the Reading Rates of Static Text Presentation.

    Science.gov (United States)

    Uetsuki, Miki; Watanabe, Junji; Ando, Hideyuki; Maruya, Kazushi

    2017-01-01

    With the growth in digital display technologies, dynamic text presentation is used widely in every day life, such as in electric advertisements and tickers on TV programs. Unlike static text reading, little is known about the basic characteristics underlying reading dynamically presented texts. Two experiments were performed to investigate this. Experiment 1 examined the optimum rate of dynamic text presentation in terms of a readability and favorability. This experiment demonstrated that, when the rate of text presentation was changed, there was an optimum presentation rate (around 6 letters/s in our condition) regardless of difficulty level. This indicates that the presentation rate of dynamic texts can affect the impression of reading. In Experiment 2, to elucidate the traits underlying dynamic text reading, we measured the reading speeds of silent and trace reading among the same participants and compared them with the optimum presentation rate obtained in Experiment 1. The results showed that the optimum rate was slower than with silent reading and faster than with trace reading, and, interestingly, the individual optimum rates of dynamic text presentation were correlated with the speeds of both silent and trace reading. In other words, the readers who preferred a fast rate in dynamic text presentation would also have a high reading speed for silent and trace reading.

  1. [The influence of psychological variables on sports performance: assessment with the Questionnaire of Sports Performance-related Psychological Characteristics].

    Science.gov (United States)

    Gimeno, Fernando; Buceta, José Maria; Pérez-Llantada, María Carmen

    2007-11-01

    The purpose of this research was to observe the relationship among psychological variables and three important issues in sports competition: achieving success, long-term continuance and sustaining injuries. Three studies were carried out with three groups of athletes from the areas of judo, football and swimming, using the Questionnaire of Sports Performance-related Psychological Characteristics as the measuring instrument. The analyses carried out revealed significantly statistical associations between the perception of stress control and of self-confidence, and between achieving success, long-term continuance in competition sports and sustaining injuries. These results indicate the importance of psychological skills training to aid sports performance and prevent injuries, as well as the use of the above-mentioned questionnaire, which, with a limited number of items, measures a wide range of psychological variables in the specific context of sports.

  2. On the Performance Evaluation and Analysis of the Hybridised Bittorrent Protocol with Partial Mobility Characteristics

    CERN Document Server

    Violaris, George C

    2010-01-01

    Engaging mobility with file sharing is considered very promising in today's run Anywhere, Anytime, Anything (3As) environments. The Bittorrent file sharing protocol can be rarely combined with the mobility scenario framework since resources are not available due to the dynamically changing topology network. As a result, mobility in P2P-oriented file sharing platforms, degrades the end-to-end efficiency and the system's performance. This work proposes a new hybridized model, which takes into account the mobility characteristics of the combined Bittorrent protocol in a centralized manner enabling partial mobility characteristics, where the clients of the network use a distinct technique to differentiate between mobile and static nodes. Many parameters were taken into consideration like the round trip delays, the diffusion process, and the seeding techniques, targeting the maximization of the average throughput in the clustered swarms containing mobile peers. Partial mobility characteristics are set in a peer-tr...

  3. Effects of Selected Corporate Governance Characteristics on Firm Performance: Empirical Evidence from Kenya

    Directory of Open Access Journals (Sweden)

    Vincent Okoth Ongore

    2011-01-01

    Full Text Available This paper examines the interrelations among ownership, board and manager characteristics and firm performance in a sample of 54 firms listed at the Nairobi Stock Exchange (NSE. These governance characteristics, designed to minimize agency problems between principals and agents are operationalized in terms of ownership concentration, ownership identity, board effectiveness and managerial discretion. The typical ownership identities at the NSE are government, foreign, institutional, manager and diverse ownership forms. Firm performance is measured using Return on Assets (ROA, Return on Equity (ROE and Dividend Yield (DY. Using PPMC, Logistic Regression and Stepwise Regression, the paper presents evidence of significant positive relationship between foreign, insider, institutional and diverse ownership forms, and firm performance. However, the relationship between ownership concentration and government, and firm performance was significantly negative. The role of boards was found to be of very little value, mainly due to lack of adherence to board member selection criteria. The results also show significant positive relationship between managerial discretion and performance. Collectively, these results are consistent with pertinent literature with regard to the implications of government, foreign, manager (insider and institutional ownership forms, but significantly differ concerning the effects of ownership concentration and diverse ownership on firm performance.

  4. Transformational leadership and safety performance among nurses: the mediating role of knowledge-related job characteristics.

    Science.gov (United States)

    Lievens, Ilse; Vlerick, Peter

    2014-03-01

    To report the impact of transformational leadership on two dimensions of nurses' safety performance (i.e. safety compliance and safety participation) and to study the mediating role of knowledge-related job characteristics in this relationship. Safety performance refers to the behaviours that employees exhibit to adhere to safety guidelines and to promote health and safety at their workplace. Nurses' safety performance is a major challenge for healthcare settings, urging the need to identify the key determinants and psychological mechanisms that influence it. A cross-sectional survey study. The study was carried out in September 2010 in a large Belgian hospital. We used self-administered questionnaires; 152 nurses participated. The hypotheses were tested using hierarchical regression analyses. In line with our first hypothesis, the results show that transformational leadership exerted a significant positive impact on both dimensions of nurses' safety performance. This positive relation was mediated by knowledge-related job characteristics, supporting our second hypothesis. Head nurses' transformational leadership can enhance nurses' compliance with and participation in safety. Furthermore, transformational head nurses are able to influence the perception that their nurses have about the kind and amount of knowledge in their job, which can also lead to increases in both dimensions of nurses' safety performance. This study therefore demonstrates the key impact that transformational head nurses have, both directly and indirectly, on the safety performance of their nurses. © 2013 John Wiley & Sons Ltd.

  5. A new optimum topology switching dc-to-dc converter

    Science.gov (United States)

    Cuk, S.; Middlebrook, R. D.

    1977-01-01

    A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamic response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), thus resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance.

  6. The effects of ethanol addition with waste pork lard methyl ester on performance, emission and combustion characteristics of a diesel engine

    Directory of Open Access Journals (Sweden)

    John Panneer Selvam Dharmaraj

    2014-01-01

    Full Text Available In the recent research, as a result of depletion of world petroleum reserves, considerable attention has been focused on the use of different alternative fuels in diesel engines. The present work aims to ensure the possibility of adding ethanol as an additive with animal fat biodiesel that is tested as an alternative fuel for diesel in a CI engine. In this study, biodiesel is obtained from waste pork lard by base-catalyzed transesterification with methanol when potassium hydroxide as catalyst. 2.5%, 5% and 7.5% by volume of ethanol is blended with neat biodiesel in order to improve performance and combustion characteristics of a diesel engine. The experimental work is carried out in a 3.7 kW, single cylinder, naturally aspirated, water cooled, direct injection diesel engine for different loads and at a constant speed of 1500 rpm. The performance, emission and combustion characteristics of biodiesel-ethanol blends are investigated by comparing them with neat biodiesel and standard diesel. The experimental test results showed that the combustion and performance characteristics improved with the increase in percentage of ethanol addition with biodiesel. When compared to neat biodiesel and standard diesel, an increase in brake thermal efficiency of 5.8% and 4.1% is obtained for BEB7.5 blend at full load of the engine. With the increase in percentage of ethanol fraction in the blends, peak cylinder pressure and the corresponding heat release rate are increased. Biodiesel-ethanol blends exhibit longer ignition delay and shorter combustion duration when compared to neat biodiesel. Optimum reduction in carbon monoxide, unburned hydrocarbon and smoke emission are attained while using BEB5 blend at full load of the engine. However, there is an adverse effect in case of nitrogen oxide emission.

  7. Physical Characteristics and Performance of Japanese Top-Level American Football Players.

    Science.gov (United States)

    Yamashita, Daichi; Asakura, Masaki; Ito, Yoshihiko; Yamada, Shinzo; Yamada, Yosuke

    2017-09-01

    Yamashita, D, Asakura, M, Ito, Y, Yamada, S, and Yamada, Y. Physical characteristics and performance of Japanese top-level American football players. J Strength Cond Res 31(9): 2455-2461, 2017-This study aimed to compare the physical characteristics and performance between top-level nonprofessional football players in Japan and National Football League (NFL) Combine invited players and between top-level and middle-level players in Japan to determine the factors that enhance performance in international and national competitions. A total of 168 American football players (>20 years) in Japan participated in an anthropometric (height and weight) and physical (vertical jump, long jump, 40-yard dash, pro-agility shuttle, 3-cone drill, and bench press repetition test) measurement program based on the NFL Combine program to compete in the selection of candidates for the Senior World Championship. All players were categorized into 1 of the 3 position groups based on playing position: skill players, big skill players, and linemen. Japanese players were additionally categorized into selected and nonselected players for the second tryout. The NFL Combine candidates had significantly better performance than selected Japanese players on all variables except on performance related to quickness among the 3 position groups. Compared with nonselected players, selected Japanese skill players had better performance in the 40-yard dash and bench press test and big skill players had better performance in the vertical jump, broad jump, and 40-yard dash. Selected and nonselected Japanese linemen were not different in any measurements. These results showed the challenges in American football in Japan, which include not only improving physical performance of top-level players, but also increasing the number of football players with good physical performance.

  8. Physical Characteristics and Performance of Japanese Top-Level American Football Players

    Science.gov (United States)

    Asakura, Masaki; Ito, Yoshihiko; Yamada, Shinzo; Yamada, Yosuke

    2017-01-01

    Abstract Yamashita, D, Asakura, M, Ito, Y, Yamada, S, and Yamada, Y. Physical characteristics and performance of Japanese top-level American football players. J Strength Cond Res 31(9): 2455–2461, 2017—This study aimed to compare the physical characteristics and performance between top-level nonprofessional football players in Japan and National Football League (NFL) Combine invited players and between top-level and middle-level players in Japan to determine the factors that enhance performance in international and national competitions. A total of 168 American football players (>20 years) in Japan participated in an anthropometric (height and weight) and physical (vertical jump, long jump, 40-yard dash, pro-agility shuttle, 3-cone drill, and bench press repetition test) measurement program based on the NFL Combine program to compete in the selection of candidates for the Senior World Championship. All players were categorized into 1 of the 3 position groups based on playing position: skill players, big skill players, and linemen. Japanese players were additionally categorized into selected and nonselected players for the second tryout. The NFL Combine candidates had significantly better performance than selected Japanese players on all variables except on performance related to quickness among the 3 position groups. Compared with nonselected players, selected Japanese skill players had better performance in the 40-yard dash and bench press test and big skill players had better performance in the vertical jump, broad jump, and 40-yard dash. Selected and nonselected Japanese linemen were not different in any measurements. These results showed the challenges in American football in Japan, which include not only improving physical performance of top-level players, but also increasing the number of football players with good physical performance. PMID:28052052

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

    Science.gov (United States)

    Dippong, Joseph; Kalkhoff, Will

    2015-03-01

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

  10. Performance characteristics of low-dissipative generalized Carnot cycles with external leakage losses

    Science.gov (United States)

    Huang, Chuan-Kun; Guo, Jun-Cheng; Chen, Jin-Can

    2015-11-01

    Under the assumption of low-dissipation, a unified model of generalized Carnot cycles with external leakage losses is established. Analytical expressions for the power output and efficiency are derived. The general performance characteristics between the power output and the efficiency are revealed. The maximum power output and efficiency are calculated. The lower and upper bounds of the efficiency at the maximum power output are determined. The results obtained here are universal and can be directly used to reveal the performance characteristics of different Carnot cycles, such as Carnot heat engines, Carnot-like heat engines, flux flow engines, gravitational engines, chemical engines, two-level quantum engines, etc. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11405032).

  11. Evaluation of the performance characteristic for mammography by using edge device

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Won [Dept. of Radiology, Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Choi, Jwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, The Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [Dept. of Medical Science, The Soonchunhyang University, Asan (Korea, Republic of); Lee, Eul Kyu [Dept. of Radiology, Inje Paik University Hospital Jeo-dong, Seoul (Korea, Republic of); Son, Soon Yong [Dept. of Radiological Technology, The Wonkwang Health Science University, Iksan (Korea, Republic of); Son, Jin Hyun; Min, Jung Whan [Dept. of Radiological Technology, The Shingu University, Sungnam (Korea, Republic of)

    2016-09-15

    The purpose of this study was to evaluation of the performance characteristic for mammography by using edge device that mammography equipment improves essential in the correct diagnosis for the maintenance. We measured the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using the 61267 RQA-M2 based on commission standard international electro-technical commission (IEC). As a results, spatial resolution of dimensions tomo and lorad selenia mammography were maintained at 10 mm-1 and NPS and DQE including the low nyquist frequency indicated to 6.0 mm-1. Therefore, regularly QA of mammography system should be necessary. This study can be contribute to evaluate QA for performance characteristic of mammography of DDR system.

  12. Talent in Female Gymnastics: a Survival Analysis Based upon Performance Characteristics.

    Science.gov (United States)

    Pion, J; Lenoir, M; Vandorpe, B; Segers, V

    2015-11-01

    This study investigated the link between the anthropometric, physical and motor characteristics assessed during talent identification and dropout in young female gymnasts. 3 cohorts of female gymnasts (n=243; 6-9 years) completed a test battery for talent identification. Performance-levels were monitored over 5 years of competition. Kaplan-Meier and Cox Proportional Hazards analyses were conducted to determine the survival rate and the characteristics that influence dropout respectively. Kaplan-Meier analysis indicated that only 18% of the female gymnasts that passed the baseline talent identification test survived at the highest competition level 5 years later. The Cox Proportional Hazards Model indicated that gymnasts with a score in the best quartile for a specific characteristic significantly increased chances of survival by 45-129%. These characteristics being: basic motor skills (129%), shoulder strength (96%), leg strength (53%) and 3 gross motor coordination items (45-73%). These results suggest that tests batteries commonly used for talent identification in young female gymnasts may also provide valuable insights into future dropout. Therefore, multidimensional test batteries deserve a prominent place in the selection process. The individual test results should encourage trainers to invest in an early development of basic physical and motor characteristics to prevent attrition. © Georg Thieme Verlag KG Stuttgart · New York.

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

    Science.gov (United States)

    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.

  14. 新型菊芋秸秆-烟煤混合固体燃料添加剂的选择与燃烧性能分析%Selecting additives for optimum combustion performance of a new-type Jerusalem artichoke-bituminous coal solid biofuel pellets

    Institute of Scientific and Technical Information of China (English)

    常子磐; 郭加汛; 赵耕毛; 王长海

    2016-01-01

    Jerusalem artichoke biomass has been used to produce biofuel and can also improve the combustion performance of bituminous coal after adding to the coal. However, Jerusalem artichoke-bituminous coal solid biofuel pellets(JAC pellets)still produce large amount of slag during combustion. Here we examined the combustion characteristics of JAC pellets after mixing with MgCO3, CaCO3, Al2O3 and Al2Si2O5(OH)5 at 3%(m﹕m)to select additives for optimum combustion performance of JAC pellets. Results showed that adding additives decreased slag-ging rates to a great extent, while absorbed acid gases effectively. Addition of CaCO3 resulted in a significant reduction in ash content and Ringelman emittance. In summary, CaCO3 improved the combustion performance of the JAC pellets and could be a promising additive for JAC pellets.%在研制新型菊芋秸秆-烟煤混合固体燃料的基础上,筛选不同添加剂[MgCO3、CaCO3、Al2O3、Al2Si2O5(OH)5]优化燃料,以提高生物质混合固体燃料的燃烧性能。将四种添加剂以3%比例(质量比)与菊芋秸秆-烟煤混合固体燃料混合,比较了不同添加剂对混合固体燃料的灰分、结渣率、放热量、烟黑、灰熔点、烟气成分等的影响。结果表明:四种添加剂对酸性气体有明显的吸附作用,且能有效降低混合固体燃料的结渣率,其中CaCO3添加剂使混合固体燃料的灰分含量、烟黑的林格曼指数下降最为明显。这表明, CaCO3添加剂能有效缓解混合固体燃料中的灰分、烟黑、酸性气体的生成,提高其燃烧性能,是一种较为理想的新型菊芋秸秆-烟煤混合固体燃料添加剂。

  15. Performance characteristics of 1977 General Motors 350 CID engine. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Boziuk, J.

    1980-02-01

    Experimental data were obtained in dynamometer tests of a 1977 GM 350 CID engine to determine fuel consumption and emissions (hydrocarbons, carbon monoxide, and oxides of nitrogen) at steady-state engine operating modes. The objective of the test was to obtain engine performance data for estimating fuel consumption and emissions for varied engine service and duty and to provide basic engine characteristic data required for the TSC Vehicle Simulator (VEHSIM).

  16. Windmilling of turbofan engine; calculation of performance characteristics of a turbofan engine under windmilling

    OpenAIRE

    A. Ramanathan

    2014-01-01

    The turbofan is a type of air breathing jet engine that finds wide use in aircraft propulsion. During the normal operation of a turbofan engine installed in aircraft, the combustor is supplied with fuel, flow to the combustor is cut off and the engine runs under so called Windmilling conditions being driven only by the ram pressure ratio by producing drag. In-depth analysis is done to study the performance characteristics at this state.

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

    Science.gov (United States)

    1985-02-01

    IU Individual in Characteristics and Unit Performance A Revlew of Research and Methods James P. Kahan, Noreen Webb, RIchard J. Shavelson, Ross M...Research and Methods James P. Kahan, Noreen Webb, Richard J. Shavelson, Ross M. Stolzenberg February 1985 Prepared for the Office of the Assistant Secretary...Members wore asked to name the people they would associate with in nonmilitary, garrison area, and field/tactical area recreational time. The number

  18. The Relationship between Transformational Leadership and Followers’ Work Characteristics and Task Performance

    OpenAIRE

    Oon Fok-Yew

    2015-01-01

    Although leaders and followers are both essential elements within the leadership process, there has been limited research regarding followers and their effects in the process. This study aims to examine the relationship between transformational leadership and followers’ work characteristics and performance, and follower’s attitudes towards a leader as a moderating variable. A questionnaire survey will be used to collect data from Malaysian multi-national corporations. The questionnaire will b...

  19. Physico Chemical Characteristics of High Performance Polymer Modified by Low and Atmospheric Pressure Plasma1

    OpenAIRE

    N Bhatnagar; Jha, S.; Bhowmik, S.; Gupta, G.; Moon, J.B.; Kim, C.G.

    2012-01-01

    In this work, the effect of low pressure plasma and atmospheric-pressure plasma treatment on surface properties and adhesion characteristics of high performance polymer, Polyether Ether Ketone (PEEK) are investigated in terms of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Atomic Force Microscopy (AFM). The experimental results show that the PEEK surface treated by atmospheric pressure plasma lead to an increase in the polar component of the surf...

  20. Physico-chemical characteristics of high performance polymer modified by low and atmospheric pressure plasma

    OpenAIRE

    Nitu, Bhatnagar; Sangeeta, Jha; Shantanu, Bhowmik; Govind, Gupta; Moon, J.; Kim, C

    2012-01-01

    In this work, the effect of low pressure plasma and atmospheric-pressure plasma treatment on surface properties and adhesion characteristics of high performance polymer, Polyether Ether Ketone (PEEK) are investigated in terms of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Atomic Force Microscopy (AFM). The experimental results show that the PEEK surface treated by atmospheric pressure plasma lead to an increase in the polar component of the surf...

  1. Cavitation performance and flow characteristic in a centrifugal pump with inlet guide vanes

    Science.gov (United States)

    Tan, L.; Zha, L.; Cao, S. L.; Wang, Y. C.; Gui, S. B.

    2015-01-01

    The influence of prewhirl regulation by inlet guide vanes (IGVs) on cavitation performance and flow characteristic in a centrifugal pump is investigated. At the impeller inlet, the streamlines are regulated by the IGVs, and the axial velocity distribution is also influenced by the IGVs. Due to the total pressure loss on the IGVs, the cavitation performance of the centrifugal pump degrades. The cavitation area in impeller with IGVs is larger than one without IGVs. The specify values of total pressure loss between the suction pipe inlet and impeller inlet for three cavitation conditions show that the IGVs will generate additional pressure loss, which is related to the IGVs angles and cavitation conditions.

  2. Demand characteristics of music affect performance on the Wonderlic Personnel Test Of Intelligence.

    Science.gov (United States)

    Verpaelst, Celissa C; Standing, Lionel G

    2007-02-01

    This study examined whether demand characteristics concerning music can change subjects' performance on the Wonderlic Personnel Test of intelligence. Participants (N= 60) were randomly assigned and informed either that Mozart's music typically enhances cognitive performance or diminishes it. They then completed the Wonderlic Personnel Test while listening to a Mozart piano sonata. The subjects with a positive set answered significantly more items correctly on the test (14%) than those with a negative set (p = .03). This result may hold implications for the study of the 'Mozart effect'.

  3. Asymptotic performance characteristics of CSMA and CSMA←CD→CSMA/CD networks

    Directory of Open Access Journals (Sweden)

    J.-T Lim

    1996-01-01

    Full Text Available This paper presents analytical formulae for performance evaluation of CSMA and CSMA/CD networks with a finite number of buffered users. The asymptotic theory developed in [1] is extended to local area networks so as to investigate the resulting steady state throughput, time delay, probability of blocking, and local stability of each equilibrium. In particular, the stabilization of CSMA and CSMA/CD networks is considered, i.e., how to choose the transmission probability so that a unique steady state with relatively high performance characteristics is achieved.

  4. Asymptotic performance characteristics of CSMA and CSMA ← CD → CSMA / CD networks

    Directory of Open Access Journals (Sweden)

    Lim J.-T

    1996-01-01

    Full Text Available This paper presents analytical formulae for performance evaluation of CSMA and CSMA/CD networks with a finite number of buffered users. The asymptotic theory developed in [1] is extended to local area networks so as to investigate the resulting steady state throughput, time delay, probability of blocking, and local stability of each equilibrium. In particular, the stabilization of CSMA and CSMA/CD networks is considered, i.e., how to choose the transmission probability so that a unique steady state with relatively high performance characteristics is achieved.

  5. The role of anthropometric characteristics in modern pentathlon performance in female athletes.

    Science.gov (United States)

    Claessens, A L; Hlatky, S; Lefevre, J; Holdhaus, H

    1994-08-01

    In order to determine the role of body build characteristics in modern pentathletes, 65 female participants at the IXth World Modern Pentathlon Championships, 1989 (Wiener Neustadt, Austria) were investigated. Of these, 54 participate in the competition; the other 11 were reserves. Their mean (+/- S.D.) age was 22.34 +/- 3.97 years (range 16.08-32.58 years). Anthropometric characteristics (body mass, lengths, breadths, girths and skinfolds), somatotype and body composition estimates were determined. Compared with other female athletes (e.g. swimmers, runners, fencers), the elite modern pentathletes were rather tall (x = 168.1 cm) and, as indicated by the body mass index (x = 21.6), they had a high mass relative to their stature. Based on skinfolds, body fat was estimated as 16%, and anthropometrically determined somatotype was on average 2.5-3.9-2.8. The relationship between the athletes' anthropometric characteristics and modern pentathlon performance was investigated by means of Pearson zero-order correlations between the physical traits and the competitive performance scores. Significant correlations were found mainly for the 'fat' variables, such as skinfolds, percent fat and the endomorphy component, r varying from -0.34 to -0.58, which indicated an inverse relationship between the amount of fatness and modern pentathlon performance. To investigate this relationship further, Pearson zero-order correlations were calculated between the respective factors scores, derived from a rotated factor pattern (Varimax) carried out on selected somatic variables, and the performance scores. The results demonstrated that, in relation to anthropometric characteristics, modern pentathlon performance in females is mainly associated with the 'fat development' factor, and to a lesser degree with the 'bone-muscle development' factor. Variables representing linearity of physique seem to be unrelated to modern pentathlon performance. Stepwise regression analysis revealed that 42

  6. Experimental and artificial neural network based prediction of performance and emission characteristics of DI diesel engine using Calophyllum inophyllum methyl ester at different nozzle opening pressure

    Science.gov (United States)

    Vairamuthu, G.; Thangagiri, B.; Sundarapandian, S.

    2017-07-01

    The present work investigates the effect of varying Nozzle Opening Pressures (NOP) from 220 bar to 250 bar on performance, emissions and combustion characteristics of Calophyllum inophyllum Methyl Ester (CIME) in a constant speed, Direct Injection (DI) diesel engine using Artificial Neural Network (ANN) approach. An ANN model has been developed to predict a correlation between specific fuel consumption (SFC), brake thermal efficiency (BTE), exhaust gas temperature (EGT), Unburnt hydrocarbon (UBHC), CO, CO2, NOx and smoke density using load, blend (B0 and B100) and NOP as input data. A standard Back-Propagation Algorithm (BPA) for the engine is used in this model. A Multi Layer Perceptron network (MLP) is used for nonlinear mapping between the input and the output parameters. An ANN model can predict the performance of diesel engine and the exhaust emissions with correlation coefficient (R2) in the range of 0.98-1. Mean Relative Errors (MRE) values are in the range of 0.46-5.8%, while the Mean Square Errors (MSE) are found to be very low. It is evident that the ANN models are reliable tools for the prediction of DI diesel engine performance and emissions. The test results show that the optimum NOP is 250 bar with B100.

  7. Performance characteristics of an energy selective electron refrigerator with double resonances

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Min; He Ji-Zhou; Tang Wei

    2009-01-01

    This paper establishes the energy selective electron (ESE) engine with double resonances as a refrigerator in one dimensional (ID) system. It consists of two infinitely large electron reservoirs with different temperatures and chemical potentials, and they are perfectly thermally insulated from each other and interaction only via a double 'idealized energy filter' whose widths are all finite. Taking advantage of the density of state and Fermi distribution in the ID system, the heat flux into each reservoir may then be calculated. Moreover, the coefficient of performance may be derived from the expressions for the heat flux into the hot and cold reservoirs. The performance characteristic curves are plotted by numerical analysis. The influences of the resonances widths, the energy position of resonance and the space of two resonances on performance of the ESE refrigerator are discussed. The results obtained here have theoretical significance for the understanding of thermodynamic performance of the micro-nano devices.

  8. Experimental study for flow characteristics and performance evaluation of butterfly valves

    Science.gov (United States)

    Kim, C. K.; Yoon, J. Y.; Shin, M. S.

    2010-08-01

    The industrial butterfly valves have been applied to transport a large of fluid with various fields of industry. Also, these are mainly used a control of fluid flux to the water and waste-water pipeline. Present, butterfly valves are manufacturing for multiplicity shape of bodies and discs with many producers. However, appropriate performance evaluation was not yet accomplished to compare about these valves through experiments. This study is performed the experiment of flow characteristics and performance of manufactured 400A butterfly valves for the water and waste pipeline, and compared experimental results. We performed experiments that were controlled fixed a differential pressure condition (1 psi) and the range of the flow rate conditions (500 m3/hr ~ 2500 m3/hr), and also opened the disc of valves to a range of angle from 9 degree to 90 degree. We investigated and compared the valve flow coefficient and the valve loss coefficient of results through experiments with each butterfly valve.

  9. Simulation programs for ph.D. study of analysis, modeling and optimum design of solar domestic hot water systems

    Energy Technology Data Exchange (ETDEWEB)

    Lin Qin

    1998-12-31

    The design of solar domestic hot water (DHW) systems is a complex process, due to characteristics inherent in the solar heating technology. Recently, computer simulation has become a widely used technique to improve the understanding of the thermal processes in such systems. One of the main objects of the Ph.D. study of `Analysis, Modelling and optimum Design of Solar Domestic Hot Water Systems` is to develop and verify programs for carrying out the simulation and evaluation of the dynamic performance of solar DHW systems. During this study, simulation programs for hot water distribution networks and for certain types of solar DHW systems were developed. (au)

  10. Fitness Landscape Analysis for Optimum Multiuser Detection Problem

    Institute of Scientific and Technical Information of China (English)

    WANG Shaowei; ZHU Qiuping

    2007-01-01

    Optimum multiuser detection (OMD) for CDMA systems is an NP-complete combinatorial optimization problem. Fitness landscape has been proven to be very useful for understanding the behavior of combinatorial optimization algorithms and can help in predicting their performance. This paper analyzes the statistic properties of the fitness landscape of the OMD problem by performing autocorrelation analysis, fitness distance correlation test and epistasis measure. The analysis results explain why some random search algorithms are effective methods for OMD problem and give hints how to design more efficient randomized search heuristic algorithms for OMD.

  11. The Effect of Modification Methods on the Performance Characteristics of Composites Based on a Linear Low-Density Polyethylene and Natural Hemp Fibers

    Science.gov (United States)

    Kajaks, J.; Zelca, Z.; Kukle, S.

    2015-11-01

    Influence of the content of hemp fibers (harvested in 2012) and their modification methods (treatment with boiling water, sodium hydroxide, and acetic anhydride) and addition of an interfacial modifier, maleated polyethylene (MAPE), on the performance characteristics (tensile strength, modulus, elongation at break, microhardness, and water resistance) of composites based on a linear low-density polyethylene (LLDPE) was investigated. The results obtained are compared with data found earlier for the same type of hemp fibers, but harvested in 2011. It is shown that optimum content of untreated hemp fibers in the LLDPE matrix is 30 wt.% and optimum length of the fibers is less than 1 mm. An increase in the content of hemp fibers (to 30 wt.%) raised the tensile strength and modulus of the composites, but reduced their elasticity and deformation ability. Simultaneously, the microhardness of the composite materials grew. Pretreating the fibers with sodium hydroxide improved the mechanical properties of the composites only slightly, but treating with acetic anhydride allowed us to elevate the content of the fibers up to 40 and 50 wt.%. The best results were achieved by addition of 50 wt.% MAPE, when the tensile modulus increased by about 47% and the tensile strength by 27% as compared with those of composites with fibers pretreated by other methods. To estimate the processing possibilities of the composites, the melt flow index (MFI) was determined. It is established that the pretreatment of the fibers significantly affects the numerical values of MFI. For example, upon treatment with acetic anhydride, a sufficiently high fluidity of the composites was retained even at a 50 wt.% content of fibers. The lowest fluidity was observed for composites with alkali-pretreated hemp fibers. The surface microhardness decreased upon their chemical pretreatment. The highest microhardness showed composites with 30 wt.% untreated fibers. The chemical pretreatment considerably raised the

  12. Optimum Operational Parameters for Yawed Wind Turbines

    Directory of Open Access Journals (Sweden)

    David A. Peters

    2011-01-01

    Full Text Available A set of systematical optimum operational parameters for wind turbines under various wind directions is derived by using combined momentum-energy and blade-element-energy concepts. The derivations are solved numerically by fixing some parameters at practical values. Then, the interactions between the produced power and the influential factors of it are generated in the figures. It is shown that the maximum power produced is strongly affected by the wind direction, the tip speed, the pitch angle of the rotor, and the drag coefficient, which are specifically indicated by figures. It also turns out that the maximum power can take place at two different optimum tip speeds in some cases. The equations derived herein can also be used in the modeling of tethered wind turbines which can keep aloft and deliver energy.

  13. OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS

    Energy Technology Data Exchange (ETDEWEB)

    LIN-LIU,YR; STAMBAUGH,RD

    2002-11-01

    OAK A271 OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS. The dependence of the ideal ballooning {beta} limit on aspect ratio, A, and elongation {kappa} is systematically explored for nearly 100% bootstrap current driven tokamak equilibria in a wide range of the shape parameters (A = 1.2-7.0, {kappa} = 1.5-6.0 with triangularity {delta} = 0.5). The critical {beta}{sub N} is shown to be optimal at {kappa} = 3.0-4.0 for all A studied and increases as A decreases with a dependence close to A{sup -0.5}. The results obtained can be used as a theoretical basis for the choice of optimum aspect ratio and elongation of next step burning plasma tokamaks or tokamak reactors.

  14. Optimum annular focusing by a phase plate

    CERN Document Server

    Arrizón, Victor; Aguirre-Olivas, Dilia; Mellado-Villaseñor, Gabriel

    2015-01-01

    Conventional light focusing, i. e. concentration of an extended optical field within a small area around a point, is a frequently used process in Optics. An important extension to conventional focusing is the generation of the annular focal field of an optical beam. We discuss a simple optical setup that achieves this kind of focusing employing a phase plate as unique optical component. We first establish the class of beams that being transmitted through the phase plate can be focused into an annular field with topological charge of arbitrary integer order q. Then, for each beam in this class we determine the plate transmittance that generates the focal field with the maximum possible peak intensity. In particular, we discuss and implement experimentally the optimum annular focusing of a Gaussian beam. The attributes of optimum annular focal fields, namely the high peak intensity, intensity gradient and narrow annular section, are advantageous for different applications of such structured fields.

  15. Class modality, student characteristics, and performance in a community college introductory STEM course

    Science.gov (United States)

    Fogle, Thomas Ty

    Research on introductory STEM course performance has indicated that student characteristics (age, ethnicity and gender) and Grade Point Average (G.P.A.) can be predictive of student performance, and by implication, a correlation among these factors can help determine course design interventions to help certain types of students perform well in introductory STEM courses. The basis of this study was a community college Visual Basic programming course taught in both online and hybrid format. Beginning students in this course represented a diverse population residing in a large, mid-western, city and surrounding communities. Many of these students were defined as "at-Risk" or "non-traditional, which generally means any combination of socio-economic, cultural, family and employment factors that indicate a student is non-traditional. Research has shown these students struggle academically in technologically dense STEM courses, and may require student services and support to achieve their individual performance goals. The overall number in the study range was 392 distance students and 287 blended course students. The main question of this research was to determine to what extent student characteristics in a community college context, and previous success, as measured in overall G.P.A., were related to course performance in an introductory Visual Basic programming (STEM) course; and, whether or not a combination of these factors and course modality was predictive of success. The study employed a quantitative, quasi-experimental design to assess whether students' course performance was linked to course modality, student characteristics and overall G.P.A. The results indicated that the only predictor of student performance was overall G.P.A. Despite the research analyzed in Chapter 2, there was no statistically significant relationship to modality, age, ethnicity, or gender to performance in the course. Cognitive load is significant in a computer programming course and it

  16. Active magnetic bearings for optimum turbomachinery design

    Science.gov (United States)

    Hustak, J.; Kirk, R. G.; Schoeneck, K. A.

    1985-01-01

    The design and shop test results are given for a high speed eight stage centrifugal compressor supported by active magnetic bearings. A brief summary of the rotor dynamics analysis is presented with specific attention given to design considerations for optimum rotor stability. The concerns for retrofit of magnetic bearings in existing machinery are discussed with supporting analysis of a four stage centrifugal compressor. Recommendations are given on design and analysis requirements for successful machinery operation of either retrofit or new design turbomachinery.

  17. Boolean computation of optimum hitting sets

    Energy Technology Data Exchange (ETDEWEB)

    Hulme, B.L.; Baca, L.S.; Shiver, A.W.; Worrell, R.B.

    1984-04-01

    This report presents the results of computational experience in solving weighted hitting set problems by Boolean algebraic methods. The feasible solutions are obtained by Boolean formula manipulations, and the optimum solutions are obtained by comparing the weight sums of the feasible solutions. Both the algebra and the optimization can be accomplished using the SETS language. One application is to physical protection problems. 8 references, 2 tables.

  18. Optimum Arrangement of Taxi Drivers’ Working Hours

    OpenAIRE

    TANIZAKI, Takashi

    2014-01-01

    Part 2: Knowledge Discovery and Sharing; International audience; We propose optimum arrangement of taxi drivers’ working hours. In Japan, income of taxi vehicle is decreasing about 11 thousand yen in the past 15 years. Then some taxi companies are investing to gain more customers. But there are many small taxi companies that are difficult to invest with much money. Therefore we have been researching the other method to gain more customers by little investment for small companies. In this pape...

  19. Techniques for evaluating optimum data center operation

    Science.gov (United States)

    Hamann, Hendrik F.; Rodriguez, Sergio Adolfo Bermudez; Wehle, Hans-Dieter

    2017-06-14

    Techniques for modeling a data center are provided. In one aspect, a method for determining data center efficiency is provided. The method includes the following steps. Target parameters for the data center are obtained. Technology pre-requisite parameters for the data center are obtained. An optimum data center efficiency is determined given the target parameters for the data center and the technology pre-requisite parameters for the data center.

  20. An optimum analysis sequence for environmental gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    De la Torre, F.; Rios M, C.; Ruvalcaba A, M. G.; Mireles G, F.; Saucedo A, S.; Davila R, I.; Pinedo, J. L., E-mail: fta777@hotmail.co [Universidad Autonoma de Zacatecas, Centro Regional de Estudis Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2010-10-15

    This work aims to obtain an optimum analysis sequence for environmental gamma-ray spectroscopy by means of Genie 2000 (Canberra). Twenty different analysis sequences were customized using different peak area percentages and different algorithms for: 1) peak finding, and 2) peak area determination, and with or without the use of a library -based on evaluated nuclear data- of common gamma-ray emitters in environmental samples. The use of an optimum analysis sequence with certified nuclear information avoids the problems originated by the significant variations in out-of-date nuclear parameters of commercial software libraries. Interference-free gamma ray energies with absolute emission probabilities greater than 3.75% were included in the customized library. The gamma-ray spectroscopy system (based on a Ge Re-3522 Canberra detector) was calibrated both in energy and shape by means of the IAEA-2002 reference spectra for software intercomparison. To test the performance of the analysis sequences, the IAEA-2002 reference spectrum was used. The z-score and the reduced {chi}{sup 2} criteria were used to determine the optimum analysis sequence. The results show an appreciable variation in the peak area determinations and their corresponding uncertainties. Particularly, the combination of second derivative peak locate with simple peak area integration algorithms provides the greater accuracy. Lower accuracy comes from the combination of library directed peak locate algorithm and Genie's Gamma-M peak area determination. (Author)

  1. Triple-head gamma camera PET: system overview and performance characteristics.

    Science.gov (United States)

    Grosev, D; Loncarić, S; Vandenberghe, S; Dodig, D

    2002-08-01

    Positron emission tomography (PET) is currently performed using either a dedicated PET scanner or scintillation gamma camera equipped with electronic circuitry for coincidence detection of 511 keV annihilation quanta (gamma camera PET system). Although the resolution limits of these two instruments are comparable, the sensitivity and count rate performance of the gamma camera PET system are several times lower than that of the PET scanner. Most gamma camera PET systems are manufactured as dual-detector systems capable of performing dual-head coincidence imaging. One possible step towards the improvement of the sensitivity of the gamma camera PET system is to add another detector head. This work investigates the characteristics of one such triple-head gamma camera PET system capable of performing triple-head coincidence imaging. The following performance characteristics of the system were assessed: spatial resolution, sensitivity, count rate performance. The spatial resolution, expressed as the full width at half-maximum (FWHM), at 1 cm radius is 5.9 mm; at 10 cm radius, the transverse radial resolution is 5.3 mm, whilst the transverse tangential and axial resolutions are 8.9 mm and 13.3 mm, respectively. The sensitivity for a standard cylindrical phantom is 255 counts.s(-1).MBq*(-1)), using a 30% width photopeak energy window. An increase of 35% in the PET sensitivity is achievable by opening an additional 30% width energy window in the Compton region. The count rate in coincidence mode, at the upper limit of the systems optimal performance, is 45 kc.s(-1) (kc=kilocounts) using the photopeak energy window only, and increases to 60 kc.s(-1) using the photopeak + Compton windows. Sensitivity results are compared with published data for a similar dual-head detector system.

  2. Cooling Performance Characteristics on Mobile Air-Conditioning System for Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Ho-Seong Lee

    2013-01-01

    Full Text Available This study investigates the cooling performance characteristics of the mobile air-conditioning system using R744 (CO2 for the hybrid electric vehicle as an alternative to both the R-134a and the conventional air-conditioning system. The developed air-conditioning system is operated with an electric driven compressor in the battery driving mode and a belt driven compressor in the engine driving mode. The cooling performance characteristics of the developed system have been analyzed by experiments under various operating conditions of inlet air temperature, air flow rates for the gas cooler side and evaporator side, and electric compressor revolution respectively. As a result, cooling performances of the tested air-conditioning system for the EDC driving mode (electricity driven compressor were better than those for the BDC driving mode (belt driven compressor. The cooling capacity and cooling COP of the tested air-conditioning system for both driving modes were over 5.0 kW and 2.0, respectively. The observed cooling performance of the tested air-conditioning system may be sufficient for the cabin cooling of hybrid electric vehicles.

  3. Can vitamin C elevate laying hen performance, egg and plasma characteristics under normal condition?

    Directory of Open Access Journals (Sweden)

    Hamid R. H. Matin

    2010-09-01

    Full Text Available The aim of this study was to investigate the effects of vitamin C on laying hen performance, egg quality and some blood parameters under thermal neutrality condition. A total of 192 laying hens (20-week-old were used by completely randomize design. The treatments, from 20 to 35 weeks of age, included four levels of vitamin C: 0 (control, 250, 500 and 750 mg/kg diet. Bird’s performance, egg characteristics, plasma glucose, calcium and uric acid were assayed at 28 and 35 weeks of age. Laying hen performance was similar among treatments (P>0.05. Greater albumen index and Haugh unit were obtained by fed 750 mg vitamin C/kg diet compared to other treatments at 28 weeks of age (P<0.05. Increased yolk height was attained by diet supplemented with 500 mg vitamin C/kg diet at this age (P<0.05. Shape index was improved (P<0.05 by 250 and 500 mg vitamin C/kg diet at 35 weeks of age. Higher yolk index was achieved by 500 mg vitamin C/kg diet at 28 and 35 weeks of age (P<0.05. Plasma uric acid was decreased by 250 mg vitamin C/kg diet compared with control diet (P<0.05. The results of the current study have shown that diets supplemented with vitamin C can improve some egg characteristics and decrease plasma uric acid, but have similar effects on performance.

  4. THE STUDY OF THE SOMATOTYPES AND PERFORMANCE CHARACTERISTICS OF BODY FOR FOOTBALL BRANCH

    Directory of Open Access Journals (Sweden)

    Vedat AYAN

    2011-12-01

    Full Text Available In this study, it was aimed to determine the somatotypes and performance characteristics of boys for football branch. 171 volunteer boys aged 9±1 participated in the study. Age, height, weight, skinfold thickness, circumference and width measurements of the boys were taken. Heath-Carter method was used to determine their somatotypes. Mean values and standart deviations of all the measurements taken were calculated. . Correlate (bivariate was apllied to determine whether there was a relationship between their somatotypes and performances. Statistical analyses of the measurements were done through SPSS 13. The mean values of the boys (n=171 participated in the study were as follows; mean weight 28,8±3,5 kg; mean height 132,1±5,3 cm, and performance mean values were; vertical jump mean value 18,6±,05 cm, standing long jump mean value 108,93±16,89 cm, 20 m run mean value 4,39±,40 sec. and the mean values of their somatotype compounds were endomorphy 3,12±,25, mesomorphy 4,02±,29, ectomorphy 3,04±,28. Pysical fitness values including athletes’ physical and athropometric characterstics are fundemental in guidance for sports. We believe that the study, besides its determining somatotypes and performance characteristics of boys, will contribute to the studies carried out in the field and also to the selection of the footballers at the early stages with the data obtained.

  5. Research on the optimum hydrogenated silicon thin films for application in solar cells

    Institute of Scientific and Technical Information of China (English)

    Lei Qing-Song; Wu Zhi-Meng; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    Hydrogenated silicon (Si:H) thin films for application in solar cells were deposited by using very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at a substrate temperature of about 170 ℃. The electrical,structural, and optical properties of the films were investigated. The deposited films were then applied as i-layers for p-i-n single junction solar cells. The current-voltage (Ⅰ - Ⅴ) characteristics of the cells were measured before and after the light soaking. The results suggest that the films deposited near the transition region have an optimum properties for application in solar cells. The cell with an i-layer prepared near the transition region shows the best stable performance.

  6. Characteristics of shift work and their impact on employee performance and wellbeing: A literature review.

    Science.gov (United States)

    Dall'Ora, Chiara; Ball, Jane; Recio-Saucedo, Alejandra; Griffiths, Peter

    2016-05-01

    To identify the characteristics of shift work that have an effect on employee's performance (including job performance, productivity, safety, quality of care delivered, errors, adverse events and client satisfaction) and wellbeing (including burnout, job satisfaction, absenteeism, intention to leave the job) in all sectors including healthcare. A scoping review of the literature was undertaken. We searched electronic databases (CINAHL, MEDLINE, PsychINFO, SCOPUS) to identify primary quantitative studies. The search was conducted between January and March 2015. Studies were drawn from all occupational sectors (i.e. health and non health), meeting the inclusion criteria: involved participants aged ≥18 who have been working shifts or serve as control group for others working shifts, exploring the association of characteristics of shift work with at least one of the selected outcomes. Reference lists from retrieved studies were checked to identify any further studies. 35 studies were included in the review; 25 studies were performed in the health sector. A variety of shift work characteristics are associated with compromised employee's performance and wellbeing. Findings from large multicentre studies highlight that shifts of 12h or longer are associated with jeopardised outcomes. Working more than 40h per week is associated with adverse events, while no conclusive evidence was found regarding working a 'Compressed Working Week'; working overtime was associated with decreased job performance. Working rotating shifts was associated with worse job performance outcomes, whilst fixed night shifts appeared to enable resynchronisation. However, job satisfaction of employees working fixed nights was reduced. Timely breaks had a positive impact on employee fatigue and alertness, whilst quick returns between shifts appeared to increase pathologic fatigue. The effect of shift work characteristics on outcomes in the studies reviewed is consistent across occupational sectors

  7. Impact of Fitness Characteristics on Tennis Performance in Elite Junior Tennis Players.

    Science.gov (United States)

    Ulbricht, Alexander; Fernandez-Fernandez, Jaime; Mendez-Villanueva, Alberto; Ferrauti, Alexander

    2016-04-01

    The impact of fitness characteristics on tennis performance in adolescent players is not clearly understood. Therefore, the aim of the present study was to test whether physical characteristics are related to players' competitive level (i.e., national youth ranking). A secondary aim was to compare adolescent tennis players by performance level (i.e., regional selected players and the national team). A total of 902 male and female junior players (aged, 11-16 years) in Germany were evaluated using a physical testing battery: grip strength; countermovement jump; 10 and 20-m sprint; tennis-specific sprint; overhead, forehand, and backhand medicine ball throws (MBT); serve velocity and tennis-specific endurance test (hit and turn tennis test). Results showed that serve velocity (r = -0.43 to 0.64 for female subjects [♀]; r = -0.33 to 0.49 for male subjects [♂]) and upper-body power (e.g., MBT r = -0.26 to -0.49 ♀; r = -0.20 to -0.49 ♂) were the most correlated predictors of tennis performance (i.e., national youth ranking) in both female and male tennis players. Moreover, national selected players showed better performance levels than their regional counterparts, mainly in the most predictive physical characteristics (i.e., serve velocity: effect size [ES], 0.78-1.04 ♀; ES 0.92-1.02 ♂, MBT: ES, 0.66-0.88 ♀; ES, 0.67-1.04 ♂) and specific endurance (ES, 0.05-0.95 ♀; ES, 0.31-0.73 ♂). The present findings underline the importance of certain physical attributes, especially serve velocity and strength- and power-related variables (upper body), and suggest the need to include these parameters in the area of training, physical testing, and talent identification of young tennis players.

  8. Optimum Identification Method of Sorting Green Household Waste

    Directory of Open Access Journals (Sweden)

    Daud Mohd Hisam

    2016-01-01

    Full Text Available This project is related to design of sorting facility for reducing, reusing, recycling green waste material, and in particular to invent an automatic system to distinguish household waste in order to separate them from the main waste stream. The project focuses on thorough analysis of the properties of green household waste. The method of identification is using capacitive sensor where the characteristic data taken on three different sensor drive frequency. Three types of material have been chosen as a medium of this research, to be separated using the selected method. Based on capacitance characteristics and its ability to penetrate green object, optimum identification method is expected to be recognized in this project. The output capacitance sensor is in analogue value. The results demonstrate that the information from the sensor is enough to recognize the materials that have been selected.

  9. Effect of Fuel Types on Combustion Characteristics and Performance of a Four Stroke IC Engine

    Directory of Open Access Journals (Sweden)

    Mrs. Rana Ali Hussein,

    2014-04-01

    Full Text Available In this study, the effect of Gasoline, Ethanol, Gasohol E10, and Kerosene on the performance and combustion characteristics of a spark ignition (SI engine were investigated. In the experiment, the internal combustion (IC engine includes one cylinder, two valves, and four stroke spark ignition. Performance tests were carried out for specific fuel consumption, brake specific fuel consumption, power developed, corrosion rate, and carbon dioxide (CO2 and carbon monoxide (CO emissions. The measurements were conducted under various engine speeds ranging from 1500 to 4500 rpm. The experimental results showed that the performance of engine was improved with the use of gasoline and gasohol E10 in comparison with the Ethanol and Kerosene. The concentrations of CO2 and CO were presented and compared for all type of fuel examined.

  10. Work-group characteristics and performance in collectivistic and individualistic cultures.

    Science.gov (United States)

    Sosik, John J; Jung, Dong I

    2002-02-01

    The authors conducted a cross-cultural longitudinal investigation of the effects of culture (individualism-collectivism dichotomy) on group characteristics (functional heterogeneity, preference for teamwork, group potency, outcome expectation) and on performance of 83 work groups performing 2 decision-making tasks over a 15-week period. The individualists (U.S. students) reported higher levels of functional heterogeneity and group potency and attained higher levels of group performance than did the collectivists (Korean students). In addition, culture and time interacted to influence ratings of group potency and outcome expectation. The difference in ratings of group potency between individualists and collectivists increased over time. Outcome expectation was greater among the collectivists in Time 1 and among the individualists in Time 2. The authors discuss implications for future cross-cultural group research and international management.

  11. Effect of cinnamon (Cinnamomum zeylanicum) essential oil supplementation on lamb growth performance and meat quality characteristics.

    Science.gov (United States)

    Simitzis, P E; Bronis, M; Charismiadou, M A; Mountzouris, K C; Deligeorgis, S G

    2014-09-01

    A trial was conducted to examine the effect of cinnamon essential oil supplementation on lamb growth performance and meat quality. Sixteen male lambs were randomly assigned to two groups. The first group served as control and was given a basal diet, and the second group was given the same diet supplemented with cinnamon oil (1 ml/kg of concentrated feed) for 35 days. Incorporation of cinnamon oil did not affect growth performance (P>0.05). Meat pH, colour, water-holding capacity, shear force, intramuscular fat and lipid oxidation values of longissimus thoracis muscle were not significantly influenced by cinnamon oil supplementation (P>0.05). The post-inoculation counts of Salmonella enteritidis and Listeria monocytogenes on raw meat during refrigerated storage for 6 days did not differ (P>0.05) between the two groups. The results show that cinnamon oil supplementation may not have the potential to improve lamb growth performance and meat quality characteristics.

  12. BOARD OF DIRECTORS, AUDIT COMMITTEE CHARACTERISTICS AND THE PERFORMANCE OF SAUDI ARABIA LISTED COMPANIES

    Directory of Open Access Journals (Sweden)

    Yahya Ali Al-Matari

    2012-01-01

    Full Text Available This study examines the relationship between the internal corporate governance mechanism related to the board of directors, the audit committee characteristics and the performance of the Saudi companies listed in the Saudi stock exchange (TADAWL in 2010, excluding financial companies. The statistical results of the study are not in line with the agency theory that board of directors and audit committee might mitigate agency problems leading to reduced agency cost by aligning the interests of controlling owners with those of the company. While audit Committee size (ACSIZE is found to have a significant relationship with firm performance (but in the opposite direction to expectation, other hypothesized variables, the proportion of non-executive directors (BODCOM, CEO Duality (DUAL, Board Size (BSIZE, Audit Committee Independence (ACIND, audit committee meeting (ACMEET were found to be as expected directions but insignificantly related to firm performance measure except the direction of the proportion of non-executive directors (BODCOM was opposite to the expectations.

  13. The gender gap reloaded: are school characteristics linked to labor market performance?

    Science.gov (United States)

    Konstantopoulos, Spyros; Constant, Amelie

    2008-06-01

    This study examines the wage gender gap of young adults in the 1970s, 1980s, and 2000 in the US. Using quantile regression we estimate the gender gap across the entire wage distribution. We also study the importance of high school characteristics in predicting future labor market performance. We conduct analyses for three major racial/ethnic groups in the US: Whites, Blacks, and Hispanics, employing data from two rich longitudinal studies: NLS and NELS. Our results indicate that while some school characteristics are positive and significant predictors of future wages for Whites, they are less so for the two minority groups. We find significant wage gender disparities favoring men across all three surveys in the 1970s, 1980s, and 2000. The wage gender gap is more pronounced in higher paid jobs (90th quantile) for all groups, indicating the presence of a persistent and alarming "glass ceiling."

  14. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hwan [Pusan National University, Busan (Korea, Republic of)

    2009-09-15

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  15. Time-dependent behaviour of high performance concrete: influence of coarse aggregate characteristics

    Directory of Open Access Journals (Sweden)

    Escadeillas G.

    2010-06-01

    Full Text Available This paper examines the influence of coarse aggregate characteristics on the time-dependent deformations of High Performances Concretes (HPC. Four concretes made using the same cement paste but incorporating different types of aggregate (rolled siliceous gravel, crushed granite, crushed limestone and crushed siliceous gravels were studied in order to investigate the effect of aggregate properties on the compressive strength, modulus of elasticity, shrinkage and creep. The results indicate that the aggregate type has a significant effect on creep and shrinkage deformations of HPC. An influence of the shape of aggregate on time-dependent deformations has also been observed. On the basis of these results, long-term behaviour seems to be correlated to the characteristics of the Interfacial Transition Zone (ITZ strongly depending on the mineralogical nature and properties of aggregates. The experimental results are compared with the values calculated using the current Eurocode 2 model in order to assess the accuracy of the predictions.

  16. Time-dependent behaviour of high performance concrete: influence of coarse aggregate characteristics

    Science.gov (United States)

    Makani, A.; Vidal, T.; Pons, G.; Escadeillas, G.

    2010-06-01

    This paper examines the influence of coarse aggregate characteristics on the time-dependent deformations of High Performances Concretes (HPC). Four concretes made using the same cement paste but incorporating different types of aggregate (rolled siliceous gravel, crushed granite, crushed limestone and crushed siliceous gravels) were studied in order to investigate the effect of aggregate properties on the compressive strength, modulus of elasticity, shrinkage and creep. The results indicate that the aggregate type has a significant effect on creep and shrinkage deformations of HPC. An influence of the shape of aggregate on time-dependent deformations has also been observed. On the basis of these results, long-term behaviour seems to be correlated to the characteristics of the Interfacial Transition Zone (ITZ) strongly depending on the mineralogical nature and properties of aggregates. The experimental results are compared with the values calculated using the current Eurocode 2 model in order to assess the accuracy of the predictions.

  17. Solar-assisted heat pumps: impact of evaporator characteristics on performance

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.

    1982-03-01

    Five water-refrigerant heat exchangers were tested as part of a program of experimental studies of solar-assisted heat pump (SAHP) components and controls. The aim of this work is to establish ways of improving on the benchmark designs of two prototype SAHPs, one each built by Northrup Incorporated and Lennox Industries Incorporated under contract to the US Department of Energy (DOE). The performance of a water source heat pump, employing any of these evaporators, can be projected using these data, in conjunction with appropriate data pertaining to the rest of the heat pump. Thus, the impact of the evaporator's characteristics on the heat pump performance as a whole may be assessed. The necessary supplementary data may be obtained from compressor curves and condenser performance data, or from test data from a heat pump for which substitution of one of the evaporators considered in this report is contemplated. The steady state performance of the Northrup prototype SAHP employing each of the heat exchangers tested is projected using these test data. The projections of coefficient of performance (COP) versus entering water temperature performance are presented along with the original test data for comparison.

  18. Channel Characteristics and Transmission Performance for Various Channel Configurations at 60 GHz

    Directory of Open Access Journals (Sweden)

    Haibing Yang

    2007-05-01

    Full Text Available Extensive measurements are conducted in room environments at 60 GHz to analyze the channel characteristics for various channel configurations. Channel parameters retrieved from measurements are presented and analyzed based on generic channel models. Particularly, a simple single-cluster model is applied for the parameter retrieval and performance evaluation. By this model, power delay profiles are simply described by a K-factor, a root-mean-squared delay spread, and a shape parameter. The considered channels are configured with the combination of omnidirectional, fan-beam, and pencil-beam antennas at transmitter and receiver sides. Both line-of-sight (LOS and non-LOS (NLOS channels are considered. Further, to evaluate the transmission performance, we analyze the link budget in the considered environments, then design and simulate an OFDM system with a data rate of 2 Gbps to compare the bit-error-rate (BER performance by using the measured and modeled channels. Both coded and uncoded OFDM systems are simulated. It is observed that the BER performance agrees well for the measured and modeled channels. In addition, directive configurations can provide sufficient link margins and BER performance for high data rate communications. To increase the coverage and performance in the NLOS area, it is preferable to apply directive antennas.

  19. MODELING AND ANALYSIS OF PERFORMANCE, COMBUSTION AND EMMISSION CHARACTERISTICS OF JATROPHA METHYL ESTER BLEND DIESEL FOR CI ENGINE WITH VARIABLE COMPRESSION RATIO

    Directory of Open Access Journals (Sweden)

    S.ABINAV VISWANATH

    2012-07-01

    Full Text Available An experimental study was conducted on a four stroke single cylinder compression ignition engine to determine the performance, combustion and exhaust emission characteristics under different compression ratio using an alternate fuel. The raw oil from the jatropha seed was subjected to transesterification process and is supplied to the engine as jatropha methyl ester (JME blended with diesel. The blends used in our paper are 10%, 20% and 30%. We found that the performance of the engine under VCR is maximum at 20% blend for CR18. The fuelconsumption is also found to be increased with, a higher proportion of jatropha curcas oil in the blend. But BSFC is low at 20% JME-D. Emission was found to be optimum at CR18 for all blends of the methyl ester. At high engine load, the peak cylinder pressure was found to be higher for 20% JME-D under compression ratio 18. Using STAR CD software, three dimensional simulations are deployed and the results generated are compared against experimental output.

  20. Exact Optimum Design of Segmented Thermoelectric Generators

    Directory of Open Access Journals (Sweden)

    M. Zare

    2016-01-01

    Full Text Available A considerable difference between experimental and theoretical results has been observed in the studies of segmented thermoelectric generators (STEGs. Because of simplicity, the approximate methods are widely used for design and optimization of the STEGs. This study is focused on employment of exact method for design and optimization of STEGs and comparison of exact and approximate results. Thus, using new highly efficient thermoelectric materials, four STEGs are proposed to operate in the temperature range of 300 to 1300 kelvins. The proposed STEGs are optimally designed to achieve maximum efficiency. Design and performance characteristics of the optimized generators including maximum conversion efficiency and length of elements are calculated through both exact and approximate methods. The comparison indicates that the approximate method can cause a difference up to 20% in calculation of some design characteristics despite its appropriate results in efficiency calculation. The results also show that the maximum theoretical efficiency of 23.08% is achievable using the new proposed STEGs. Compatibility factor of the selected materials for the proposed STEGs is also calculated using both exact and approximate methods. The comparison indicates a negligible difference in calculation of compatibility factor, despite the considerable difference in calculation of reduced efficiency (temperature independence efficiency.

  1. The relationships among body composition, anaerobic performance and back strength characteristics of sub-elite athletes

    Directory of Open Access Journals (Sweden)

    Cem Sinan Aslan

    2011-05-01

    Full Text Available The purpose of this study was to determine the relationship among age, height, body weight, body fat percentage, long jump (standing, vertical jump, 20 meter sprint, back strength, relative strength and anaerobic power characteristics of the 80 sub-elit male athletes who are students at a physical education and sports department and participate competitions.  In this study, 80 male students at 22.17 ± 1.97 average age who have been doing exercises regularly, were participate as voluntary. Firstly, their age, height, body weight and skin fold values were determined. Body fat percentage was estimated by Zorba Formula. Anaerobic performance was determined via long jump (standing, vertical jump and 20 meter sprint. Relative strength was estimated with “back strength / body weight” formula. Then, the relationships among body composition, anaerobic performance and back strength characteristics of the participants were determined by Pearson correlation analysis. Analyses of collected data were used by SPSS for Windows (Ver. 10 and alpha level was set as 0.05 for statistical significance.Correlation analysis’ results indicated that there were statically significant correlations among lots of physical and physiological parameters. In conclusion; it was determined that height, body weight, body fat percentage and back strength were played an explicit role on anaerobic performance of athletes.

  2. Effects of ractopamine hydrochloride on growth performance and carcass characteristics in wool and hair lambs

    Directory of Open Access Journals (Sweden)

    Ángel M. Romero-Maya

    2013-06-01

    Full Text Available This study aimed at evaluating the effects of ractopamine hydrochloride (RAC on growth performance and carcass characteristics of wool and hair lambs. For this purpose, 48 lambs averaging 31.3 kg body weight, of which twenty were wool (Ramboullet x Suffolk and twenty eight were hair (Tabasco lambs, and four levels of RAC (0, 10, 20, and 30 mg/kg diet, dry matter basis were used. Wool lambs fed 20 and 30 mg RAC had higher (P<0.05 total gain weight and lower feed conversion than 0 and 10 mg RAC. Wool lambs fed 20 mg RAC had the highest carcass weight, dressing, legs weight and longissimus area as compared to 0, 10 and 30 mg RAC.  In hair lambs there were not effect of RAC on growth performance and carcass characteristics.It was concluded that addition of RAC to finishing diets offered the best growth performance and carcass traits in wool lambs as compared to hair lambs. 

  3. Combustion, emission and engine performance characteristics of used cooking oil biodiesel - A review

    Energy Technology Data Exchange (ETDEWEB)

    Enweremadu, C.C. [Department of Mechanical Engineering, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa); Rutto, H.L. [Department of Chemical Engineering, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa)

    2010-12-15

    As the environment degrades at an alarming rate, there have been steady calls by most governments following international energy policies for the use of biofuels. One of the biofuels whose use is rapidly expanding is biodiesel. One of the economical sources for biodiesel production which doubles in the reduction of liquid waste and the subsequent burden of sewage treatment is used cooking oil (UCO). However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. This paper attempts to collect and analyze published works mainly in scientific journals about the engine performance, combustion and emissions characteristics of UCO biodiesel on diesel engine. Overall, the engine performance of the UCO biodiesel and its blends was only marginally poorer compared to diesel. From the standpoint of emissions, NOx emissions were slightly higher while un-burnt hydrocarbon (UBHC) emissions were lower for UCO biodiesel when compares to diesel fuel. There were no noticeable differences between UCO biodiesel and fresh oil biodiesel as their engine performances, combustion and emissions characteristics bear a close resemblance. This is probably more closely related to the oxygenated nature of biodiesel which is almost constant for every biodiesel (biodiesel has some level of oxygen bound to its chemical structure) and also to its higher viscosity and lower calorific value, which have a major bearing on spray formation and initial combustion. (author)

  4. Performance characteristics of mobile MOSFET dosimeter for kilovoltage X-rays used in image guided radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2015-01-01

    Full Text Available The main objective of this study was to investigate the characteristics of metal oxide semiconductor field effect transistor (MOSFET dosimeter for kilovoltage (kV X-ray beams in order to perform the in vivo dosimetry during image guidance in radiotherapy. The performance characteristics of high sensitivity MOSFET dosimeters were investigated for 80, 90, 100, 110, 120, and 125 kV X-ray beams used for imaging in radiotherapy. This study was performed using Clinac 2100 C/D medical electron linear accelerator with on-board imaging and kV cone beam computed tomography system. The characteristics studied in this work include energy dependence, angular dependence, and linearity. The X-ray beam outputs were measured as per American Association of Physicists in Medicine (AAPM TG 61 recommendations using PTW parallel plate (PP ionization chamber, which was calibrated in terms of air kerma (Nk by the National Standard Laboratory. The MOSFET dosimeters were calibrated against the PP ionization chamber for all the kV X-ray beams and the calibration coefficient was found to be 0.11 cGy/mV with a standard deviation of about ±1%. The response of MOSFET was found to be energy independent for the kV X-ray energies used in this study. The response of the MOSFET dosimeter was also found independent of angle of incidence for the gantry angles in the range of 0° to 360° in-air as well as at 3 cm depth in tissue equivalent phantom.

  5. Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance.

    Science.gov (United States)

    Sakaguchi, Yutaka; Aiba, Eriko

    2016-01-01

    Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon's exercise, J. S. Bach's Invention, Mozart's Sonatas, and Debussy's Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists.

  6. Relationship between Musical Characteristics and Temporal Breathing Pattern in Piano Performance

    Science.gov (United States)

    Sakaguchi, Yutaka; Aiba, Eriko

    2016-01-01

    Although there is growing evidence that breathing is modulated by various motor and cognitive activities, the nature of breathing in musical performance has been little explored. The present study examined the temporal breath pattern in piano performance, aiming to elucidate how breath timing is related to musical organization/events and performance. In the experiments, the respiration of 15 professional and amateur pianists, playing 10 music excerpts in total (from four-octave C major scale, Hanon's exercise, J. S. Bach's Invention, Mozart's Sonatas, and Debussy's Clair de lune), was monitored by capnography. The relationship between breathing and musical characteristics was analyzed. Five major results were obtained. (1) Mean breath interval was shortened for excerpts in faster tempi. (2) Fluctuation of breath intervals was reduced for the pieces for finger exercise and those in faster tempi. Pianists showing large within-trial fluctuation also exhibited large inter-excerpt difference. (3) Inter-trial consistency of the breath patterns depended on the excerpts. Consistency was generally reduced for the excerpts that could be performed mechanically (i.e., pieces for finger exercise), but interestingly, one third of the participant showed consistent patterns for the simple scale, correlated with the ascending/descending sequences. (4) Pianists tended to exhale just after the music onsets, inhale at the rests, and inhibit inhale during the slur parts. There was correlation between breathing pattern and two-voice polyphonic structure for several participants. (5) Respiratory patterns were notably different among the pianists. Every pianist showed his or her own characteristic features commonly for various musical works. These findings suggest that breathing in piano performance depends not only on musical parameters and organization written in the score but also some pianist-dependent factors which might be ingrained to individual pianists. PMID:27516736

  7. Performance Characteristics of Endoscopic Ultrasound in the Staging of Pancreatic Cancer: A Meta-Analysis

    Science.gov (United States)

    Nawaz, Haq; Yi-Fan, Chen; Kloke, John; Khalid, Asif; McGrath, Kevin; Landsittel, Douglas; Papachristou, Georgios I

    2014-01-01

    Context The optimal approach to pre-operative imaging assessment of pancreatic cancer is unknown. Objective The aim of this meta-analysis was to assess accuracy and performance characteristics of EUS in determining nodal staging, vascular invasion, and prediction of resectability of pancreatic cancer. A secondary aim was to perform head to head comparison of performance characteristics between EUS and CT for nodal staging, vascular invasion and resectability. Design Data from EUS studies were pooled according to bivariate generalized random effects model. Pooled estimates for CT were obtained from studies which performed head to head comparison between EUS and CT. Patients Patients with pancreatic cancer undergoing pre-operative imaging assessment. Intervention EUS. Main outcome measure Pooled sensitivity, specificity, positive and negative predictive values of EUS for nodal staging, vascular invasion and resectability. Results Forty-nine studies were considered of which 29 met inclusion criteria with a total of 1,330 patients. Pooled summary estimates for EUS-nodal staging were 69% for sensitivity and 81% for specificity. For vascular invasion, sensitivity was 85% and specificity was 91%. The sensitivity and specificity for resectability was 90% and 86%, respectively. CT scan showed lower sensitivity than EUS for nodal staging (24% vs. 58%) and vascular invasion (58% vs. 86%); however, the specificities for nodal staging (88% vs. 85%) and vascular invasion (95% vs. 93%) were comparable in studies where both imaging techniques were performed. The sensitivity and specificity of CT in determining resectability (90% and 69%) was similar to that of EUS (87% and 89%). Conclusions EUS is an accurate pre-operative tool in the assessment of nodal staging, vascular invasion and resectability in patients with pancreatic cancer. PMID:24018593

  8. Performance characteristics of lead oxides in pasted lead/acid battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Afifi, S.E. (Electrometallurgy Lab., Central Metallurgical Research and Development Inst., Cairo (Egypt)); Saba, A.E. (Electrometallurgy Lab., Central Metallurgical Research and Development Inst., Cairo (Egypt)); Shenouda, A.Y. (Electrometallurgy Lab., Central Metallurgical Research and Development Inst., Cairo (Egypt))

    1993-10-15

    The performance characteristics of lead oxides used for the pasted type of lead/acid battery plate have been investigated. The [alpha]- and [beta]-PbO polymorphs have been prepared carefully and used for pasting model electrodes. The factors that may affect the electrical capacity of such electrodes have been studied. These are: the type of oxide; percentage of free lead; additives such as carboxymethyl cellulose, zeolite and graphite. Lead hydroxide has also been studied with special attention. Photomicrographs have been taken to examine the crystal forms that develop on the electrode surface. Finally, some industrial samples have been investigated. (orig.)

  9. Characteristics and Performance of the CCD Photometric System at Lulin Observatory

    Institute of Scientific and Technical Information of China (English)

    Daisuke Kinoshita; Chin-Wei Chen; Hung-Chin Lin; Zhong-Yi Lin; Kui-Yun Huang; Yung-Shin Chang; Wen-Ping Chen

    2005-01-01

    The Lulin One-meter Telescope at Lulin Observatory in Taiwan started open-use observations in J anuary 2003. In order to evaluate the performance of the CCD photometric system, the characteristics and quality of the site, we obtained data of photometric standards as well as calibration data from February to November 2004. We report here the results of our analysis including the gain,readout noise, dark current and linearity of the CCD camera, and transformation coefficients, total throughputs, night sky brightnesses and limiting magnitudes for UBVRI bands.

  10. Improving the performance of predicting users' subjective evaluation characteristics to reduce their fatigue in IEC.

    Science.gov (United States)

    Wang, Shangfei; Takagi, Hideyuki

    2005-01-01

    Users' fatigue is the biggest technological hurdle facing Interactive Evolutionary Computation (IEC). This paper introduces the idea of "absolute scale" and "neighbour scale" to improve the performance of predicting users' subjective evaluation characteristics in IEC, and thus it will accelerate EC convergence and reduce users' fatigue. We experimentally evaluate the effect of the proposed method using two benchmark functions. The experimental results show that the convergence speed of IEC using the proposed predictor, which learns from absolute evaluation data, is much faster than the conventional one, which learns from relative data, especially in early generations. Also, IEC with predictors that use recent data are more effective than those which use all past data.

  11. Using CFD to Establish a Correlation between Design Parameters and Performance Characteristics for Seat valves

    DEFF Research Database (Denmark)

    Andersen, T. O.; Hansen, M. R.; Sørensen, H. L.

    2003-01-01

    . There are many results of steady state characteristics of these valve designs, but mostly based on analyses of the flow force behaviour in order to optimise the performance of a certain design in a specific operating range. Here the aim is to establish a correlation between the overall flow field...... and the internal valve geometry in order to have a more general design tool. The results are some general design rules for flow and flow force coefficients expressed as functions of Reynolds number and valve geometry....

  12. Evaluation of Performance and Emission characteristics of Turbocharged Diesel Engine with Mullite as Thermal Barrier Coating

    OpenAIRE

    P. N. Shrirao; A. N. Pawar

    2011-01-01

    Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3 .2SiO2 (mullite) (Al2O3= 60%, SiO2= 40%) over a 150 μm thickness of NiCrAlY bond coat. Tests were carried out on standard engine (uncoated) and low heatrejection (LHR) engine with and without turbocharger. This paper is intended to emphasis on energy balance and emission characteristic for standard engine (uncoated) ...

  13. Effect of Vitamin C on Performance, Egg Characteristics and Some Blood Parameters of Laying Hens

    Directory of Open Access Journals (Sweden)

    M.M.H Rahmati

    2012-02-01

    Full Text Available This experiment was conducted to evaluate the effects of vitamin C on laying hens performance, egg characteristics and some blood parameters under normal rearing condition. One hundred and ninety two 24 - weeks - old laying hens diet were used in a completely randomized design with 4 treatments (0, 250, 500 and 750 mg vitamin C/kg diet and 4 replicates for 105 days. Although feed consumption, feed conversion ratio and hen–day egg production were similar among treatments (P>0.05, final body weight was significantly increased (P

  14. Effect of rearing system and season on the performance and egg characteristics of Ancona laying hens

    OpenAIRE

    2010-01-01

    Productive performance and egg characteristics of Ancona laying hens reared under three different rearing systems (conventional, organic and organic-plus) were compared during an experimental period of one year. Three-hundred-sixty Ancona female chicks at 28 days of age were divided in three groups and assigned to different rearing systems. The organic group had 4m2 pasture/hen according to the requirements imposed by the EC Regulation 1804/99, whereas the organic-plus group had a larger gras...

  15. Performance Characteristics and Temperature Compensation Method of Fluid Property Sensor Based on Tuning-Fork Technology

    Directory of Open Access Journals (Sweden)

    Yuan Chen

    2016-01-01

    Full Text Available Fluid property sensor (FPS based on tuning-fork technology is applied to the measurement of the contaminant level of lubricant oil. The measuring principle of FPS sensor is derived and proved together with its resolution. The performance characteristics of the FPS sensor, such as sensitivity coefficient, resolution, and quality factor, are analyzed. A temperature compensation method is proposed to eliminate the temperature-dependence of the measuring parameters, and its validity is investigated by numerical simulation of sensitivity, oscillating frequency, and dielectric constant. The values of purification efficiency obtained using microwave and without microwave are compared experimentally.

  16. Design considerations and performance characteristics of high concentration point-focussing photovoltaic modules

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J.A.; Broadbent, S.

    1984-05-01

    Through the auspices of the Department of Energy, the Fresnel lens point-focussing photovoltaic module has evolved into a commercially available, high efficiency low cost option for converting solar energy into electricity. The 15.4% efficient baseline module is undergoing several design improvements to achieve higher efficiencies at high concentrations and lower cost. A 16.5% module will be available in 1984 and 18% Gallium Arsenide modules in 1985. This paper describes the design details and performance characteristics of the baseline module and the design improvements.

  17. Growth performance and carcass characteristics of feedlot cattle fed different levels of macadamia oil cake.

    Science.gov (United States)

    Acheampong-Boateng, O; Mikasi, M S; Benyi, K; Amey, A K A

    2008-04-01

    Eighteen cattle (six Bonsmara males, seven Simmanteler x Beefmaster males and five Simmanteler x Beefmaster females) were assigned to three diets containing 0% (Control), 10% and 20% Macadamia oil cake to evaluate the effects of different levels of Macadamia oilcake (MOC) on feed intake, growth performance and carcass characteristics of feedlot cattle. Differences in average feed intake were not significant (P > 0.05). Average daily gains on the 0% and 20% MOC diets were not significantly different (P 0.05). There were no condemned livers, suggesting that either there were no toxic factors in the feed or, even if present, were probably inactive in the liver.

  18. Identifying the performance characteristics of a winning outcome in elite mixed martial arts competition.

    Science.gov (United States)

    James, Lachlan P; Robertson, Sam; Haff, G Gregory; Beckman, Emma M; Kelly, Vincent G

    2017-03-01

    To determine those performance indicators that have the greatest influence on classifying outcome at the elite level of mixed martial arts (MMA). A secondary objective was to establish the efficacy of decision tree analysis in explaining the characteristics of victory when compared to alternate statistical methods. Cross-sectional observational. Eleven raw performance indicators from male Ultimate Fighting Championship bouts (n=234) from July 2014 to December 2014 were screened for analysis. Each raw performance indicator was also converted to a rate-dependent measure to be scaled to fight duration. Further, three additional performance indicators were calculated from the dataset and included in the analysis. Cohen's d effect sizes were employed to determine the magnitude of the differences between Wins and Losses, while decision tree (chi-square automatic interaction detector (CHAID)) and discriminant function analyses (DFA) were used to classify outcome (Win and Loss). Effect size comparisons revealed differences between Wins and Losses across a number of performance indicators. Decision tree (raw: 71.8%; rate-scaled: 76.3%) and DFA (raw: 71.4%; rate-scaled 71.2%) achieved similar classification accuracies. Grappling and accuracy performance indicators were the most influential in explaining outcome. The decision tree models also revealed multiple combinations of performance indicators leading to victory. The decision tree analyses suggest that grappling activity and technique accuracy are of particular importance in achieving victory in elite-level MMA competition. The DFA results supported the importance of these performance indicators. Decision tree induction represents an intuitive and slightly more accurate approach to explaining bout outcome in this sport when compared to DFA. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  19. Thermal Comfort and Optimum Humidity Part 1

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  20. Thermal Comfort and Optimum Humidity Part 2

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  1. DESIGN AND IMPLEMENTATION OF OPTIMUM INTERPOLATION FILTER USING FARROW STRUCTURE

    Directory of Open Access Journals (Sweden)

    NAVJOT SINGH,

    2011-05-01

    Full Text Available The Farrow Structure provides an efficient way to implement the interpolation filter using polynomialapproximation method for arbitrary sample rate change. The lagrange polynomial approximation method providesalmost exact reconstruction of the new interpolated signal as of the input sampled signal. In this paper, cubiclagrange polynomial and 4th order lagrange polynomial approximation methods have been used to implement thedesign of the interpolation filter based on Farrow Structure. The optimum filter coefficients have been calculatedusing both polynomial approximation methods. The performance of the two methods has been compared to get theoptimum solution to the design of the interpolation filter using Farrow structure.

  2. Impedance matching, optimum velocity, and ideal middle ears.

    Science.gov (United States)

    Peake, W T; Rosowski, J J

    1991-05-01

    One way to assess an ear's performance as a receiver of acoustic power is to consider impedance matching at the tympanic membrane. Assumptions about some of the impedances involved have lead to the idea of an optimum velocity magnitude (per unit pressure), which has been used as a test of middle-ear performance. We show that this approach is not a realistic way to assess effectiveness of power absorption at the tympanic membrane. More generally, we suggest that, if the performance of the combined external-and-middle ear in collecting acoustic power and delivering it to the inner ear is considered, the external- and middle-ear power-transfer efficiencies, as well as impedance matching, are involved in relating performance to an ideal.

  3. Optimum Route Selection for Vehicle Navigation

    Directory of Open Access Journals (Sweden)

    Dalip

    2016-02-01

    Full Text Available The objective of Optimum Route Selection for Vehicle Navigation System (ORSVNS article is to develop a system, which provides information about real time alternate routes to the drivers and also helps in selecting the optimal route among all the alternate routes from an origin to destination. Two types of query systems, special and general, are designed for drivers. Here, the criterion for route selection is introduced using primary and secondary road attributes. The presented methodology helps the drivers in better decision making to choose optimal route using fuzzy logic. For experimental results ORSVNS is tested over 220 km portion of Haryana state in India.

  4. The impact of green roof ageing on substrate characteristics and hydrological performance

    Science.gov (United States)

    De-Ville, Simon; Menon, Manoj; Jia, Xiaodong; Reed, George; Stovin, Virginia

    2017-04-01

    Green roofs contribute to stormwater management through the retention of rainfall and the detention of runoff. However, there is very limited knowledge concerning the evolution of green roof hydrological performance with system age. This study presents a non-invasive technique which allows for repeatable determination of key substrate characteristics over time, and evaluates the impact of observed substrate changes on hydrological performance. The physical properties of 12 green roof substrate cores have been evaluated using non-invasive X-ray microtomography (XMT) imaging. The cores comprised three replicates of two contrasting substrate types at two different ages: unused virgin samples; and 5-year-old samples from existing green roof test beds. Whilst significant structural differences (density, pore and particle sizes, tortuosity) between virgin and aged samples of a crushed brick substrate were observed, these differences did not significantly affect hydrological characteristics (maximum water holding capacity and saturated hydraulic conductivity). A contrasting substrate based upon a light expanded clay aggregate experienced increases in the number of fine particles and pores over time, which led to increases in maximum water holding capacity of 7%. In both substrates, the saturated hydraulic conductivity estimated from the XMT images was lower in aged compared with virgin samples. Comparisons between physically-derived and XMT-derived substrate hydrological properties showed that similar values and trends in the data were identified, confirming the suitability of the non-invasive XMT technique for monitoring changes in engineered substrates over time. The observed effects of ageing on hydrological performance were modelled as two distinct hydrological processes, retention and detention. Retention performance was determined via a moisture-flux model using physically-derived values of virgin and aged maximum water holding capacity. Increased water holding

  5. Flow characteristics and performance evaluation of butterfly valves using numerical analysis

    Science.gov (United States)

    Jeon, S. Y.; Yoon, J. Y.; Shin, M. S.

    2010-08-01

    The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

  6. Performance characteristics of the 12 GHz, 200 watt transmitter experiment package for CTS

    Science.gov (United States)

    Miller, E. F.; Fiala, J. L.; Hansen, I. G.

    1975-01-01

    The experiment package consists of a 200 W output stage tube (OST) powered by a power processing system (PPS). Descriptions of both the PPS and OST are given. The PPS provides the necessary voltages with a measured dc/dc conversion efficiency of 89 percent. The OST, a traveling wave tube with multiple collectors, has a saturated rf output power of 224 W and operates at an overall efficiency exceeding 40 percent over an 85 MHz bandwidth at 12 GHz. OST performance given includes frequency response, saturation characteristics, group delay, AM to PM conversion, inter-modulation distortion, and two channel gain suppression. Single and dual channel FM video performance is presented. It was determined that for 12 MHz peak to peak frequency deviation on each channel, dual channel FM television signals can be transmitted through the TEP at 60 W, each channel, with 40 MHz channel spacing (center to center).

  7. An Overview of Performance Characteristics, Experiences and Trends of Aerospace Engine Bearings Technologies

    Institute of Scientific and Technical Information of China (English)

    Ebert Franz-Josef

    2007-01-01

    In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today's material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important rolls in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH & Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.

  8. Effect of Chromite-Silica Sands Characteristics on Performance of Ladle Filler Sands for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Free opening rate is mainly determined by the performance of the ladle filler sand. High free opening rates of ladles are required in steel making to improve steel quality. Chromite ladle filler sands are one of the most widely used ladle filler sand. Several operative variables and materials characteristics affect the performance of the sands. Three sets of chromite ladle filler sands were selected and researches were focused on the sintering hehaviour and per- formance of the sands under operative conditions. The effect of particle size distribution on sintering, microstruc- ture, flowability, and permeability were presented. In all cases, the particle size varies from 0.1 to 1.5 mm corre- sponding to free flowing powders. One of the samples has higher permeability factor in comparison with others due to low particle size distribution. The other sample presents very good free opening due to its very good flowability and permeability factor.

  9. Psychological determinants of health and performance: the tangled web of desirable and undesirable characteristics.

    Science.gov (United States)

    Robbins, A S; Spence, J T; Clark, H

    1991-11-01

    Correlations were determined for male (n = 225) and female (n = 242) college students between sets of undesirable personality traits (anxiety, stress reactivity, anger, and alienation) and desirable personality traits (instrumentality, achievement strivings, and optimism measured by the Scheier-Carver [1987] Life Orientation Test), and a series of outcome variables related to health (self-reported health complaints and health maintenance behaviors and beliefs) and academic performance (academic expectations and actual grade point average). Significant correlations were found between many of the personality variables and the outcome variables. However, partial correlations revealed different relationships for the various criteria. With other variables held constant, health complaints were related to several undesirable characteristics, whereas health maintenance behaviors and beliefs were related to several desirable attributes. Only achievement strivings made an independent contribution in both sexes to the 2 measures of academic performance. The theoretical and methodological wisdom of using measures of multiple personality constructs and outcome variables is discussed.

  10. Does excess dietary protein improve growth performance and carcass characteristics in heat-exposed chickens?

    Science.gov (United States)

    Temim, S; Chagneau, A M; Guillaumin, S; Michel, J; Peresson, R; Tesseraud, S

    2000-03-01

    The effects of two environmental temperatures (22 and 32 C, constant) and five dietary protein contents (10 to 33% CP) were investigated in 4- to 6-wk-old broiler chickens. High ambient temperature reduced growth rate, feed efficiency, and breast muscle proportion and increased abdominal fat proportion. Irrespective of ambient temperature, increasing dietary protein content improved growth performance and carcass characteristics. At 32 C, there was a greater heterogeneity of the data, and bird responses were lower than at 22 C. We concluded that under conditions of chronic heat exposure, diets containing the highest protein levels, 28% and 33% compared with 20% CP, slightly improved chick performance. However, the effect was low and, in our experimental conditions, modifying dietary protein supply (variations in the total quantity of protein) is not sufficient to help broilers to withstand hot conditions.

  11. Performance Characteristics of Vapor Compression Refrigeration Cycle Based on Ericsson Cycle

    Science.gov (United States)

    Ino, Nobumi; Kishi, Takayuki; Nishio, Toshio

    The purpose of this research and investigation is to confirm and clarify the performance characteristics of the vapor compression refrigeration cycle based on the Ericsson Cycle (referred to hereinafter as "this cycle" in this paper). The theoretical analysis and comparison in performance of the conventional refrigeration cycle with this cycle using 12 different but typical refrigerants, produced the following essential and interesting results, i.e., (1) there are conditions for maximizing the COP of this cycle using the expansion valve, (2)both the COP and refrigeration capacity using this cycle showed improvement for all refrigerants other than R717 and R32, (3)the improvement rate for the COP and the refrigeration capacity becomes larger as the specific heat ratio at the gas outlet point of the regenerative heat exchanger becomes smaller, with the rate value differing according to the type of refrigerant.

  12. Performance Characteristics of a Modularized and Integrated PTC Heating System for an Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Yoon Hyuk Shin

    2015-12-01

    Full Text Available A modularized positive temperature coefficient heating system has controller-integrated heater modules. Such a heating system that uses a high-voltage power of 330 V was developed in the present study for use in electric vehicles. Four heater modules and one controller with an input power of 5.6 kW were integrated in the modularized system, which was designed for improved heating power density and light weight compared to the conventional heating system, in which the controller is separated. We experimentally investigated the performance characteristics, namely, the heating capacity, energy efficiency, and pressure drop, of a prototype of the developed heating system and found it to have satisfactory performance. The findings of this study will contribute to the development of heating systems for electric vehicles.

  13. Evaluation of the GLD360 performance characteristics using rocket-and-wire triggered lightning data

    Science.gov (United States)

    Mallick, S.; Rakov, V. A.; Ngin, T.; Gamerota, W. R.; Pilkey, J. T.; Hill, J. D.; Uman, M. A.; Jordan, D. M.; Nag, A.; Said, R. K.

    2014-05-01

    We estimated the performance characteristics of the Global Lightning Dataset (GLD360) using rocket-and-wire triggered lightning data acquired at Camp Blanding, Florida, in 2011-2013. The data set consisted of 201 return strokes and 84 kiloampere-scale (≥1 kA) superimposed pulses (initial continuous current pulses and M components) in 43 flashes. All the events transported negative charge to ground. The GLD360 detected 75 strokes and 4 superimposed pulses in 29 flashes. The resultant detection efficiencies were 67% for flashes, 37% for strokes, and 4.8% for superimposed pulses. Out of 75 detected strokes, one (1.3%) was reported with incorrect polarity. The median location error was 2.0 km, and the median absolute current estimation error was 27%. This is the first comprehensive evaluation of GLD360 performance characteristics relative to absolute ground truth, with all previous evaluations being at least in part relative to other locating systems. The results presented in this work may be applicable to regions in and around Florida.

  14. Growth performance, carcass characteristics and meat quality of finishing bulls fed crude glycerin-supplemented diets

    Directory of Open Access Journals (Sweden)

    Mônica Chaves Françozo

    2013-04-01

    Full Text Available This study was conducted to evaluate the performance, carcass characteristics and chemical composition of Longissimusmuscle (LM of the bulls. Twenty-four Nellore bulls were used in a complete randomised design. The bulls were randomly assigned to one of the three diets containing 0, 5 or 12% glycerin. Final BW and ADG were similar (P>0.05 between the bulls fed with 5 or 12% of glycerin but were higher (P0.05 by glycerin level. Hot carcass weight increased (P0.05 the conformation, colour, texture, marbling and pH. There was difference (P>0.05 for moisture, ashes and crude protein among glycerin levels. Bulls fed 12% glycerin present the highest (P<0.03 total lipids on LM. The percentage of saturated fatty acids (SFA, monounsaturated acids (MUFA, polyunsaturated acids (PUFA, n-6 and n-3 fatty acids and PUFA/SFA and n-6:n-3 ratios of the LM were similar among the diets. In conclusion, glycerin level did not affect the animal performance and carcass characteristics of Nellore bulls finished in feedlot.

  15. Combustion, performance and emissions characteristics of a newly developed CRDI single cylinder diesel engine

    Indian Academy of Sciences (India)

    Avinash Kumar Agarwal; Paras Gupta; Atul Dhar

    2015-09-01

    For improving engine performance, combustion and controlling emissions from compression ignition (CI) engines, common rail direct injection (CRDI) technology offers limitless possibilities by controlling fuel injection parameters such as fuel injection pressure, start of injection (SOI) timing, rate of fuel injection and injection duration. CRDI systems available commercially are quite complex and use a large number of sensors, hardware and analytical circuits, which make them very expensive and unfeasible for cheaper single cylinder engines, typically used in agricultural sector and decentralized power sector. This paper covers experimental investigations of a simpler version of CRDI system developed for a constant-speed, single-cylinder engine. Modifications in the cylinder head for accommodating solenoid injector, designing injector driver circuit and development of high pressure stage controls were some of the engine modification and development tasks undertaken. SOI timing is an important parameter for improving engine's combustion characteristics. SOI timings were varied between 25° and 40° BTDC for investigating engine's performance, emissions and combustion characteristics. Advanced fuel injections showed higher heat release rate (HRR), cylinder pressure and rate of pressure rise (RoPR) because of relatively longer ignition delay experienced. Lowest brake specific fuel consumption (BSFC) was obtained for 34° CA BTDC SOI. Reduction in engine out emissions except NOx was observed for advanced fuel injection timings for this newly developed CRDI system.

  16. Performance of maleated castor oil based plasticizer on rubber: rheology and curing characteristic studies

    Science.gov (United States)

    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.

  17. Performance Characteristics of Hybrid Cycle Combined Absorption Heat Transformer and Absorption Refrigerating Machine

    Science.gov (United States)

    Iyoki, Shigeki; Otsuka, Shin-Ichi; Uemura, Tadashi

    In this paper, four kinds of hybrid cycles which combined the single-stage absorption refrigerating machine and four kinds of absorption heat transformers were proposed. It is possible that each of these hybrid cycles gets high temperature and low temperature from one cycle, simultaneously. As basic cycle of absorption heat transformer, the following were chosen: two kinds of single-stage absorption heat transformer and two kinds of two-stage absorption heat transformer. As a working medium-absorbent system, H2O-LiBr system, H2O-LiBr-LiNO3 system, H2O-LiBr-LiNO3-LiCl system, H2O-LiBr-C2H6O2 system and H2O-LiNO3-LiCl system were adopted. Using these five kinds of working medium-absorbent system, the performance characteristics of four kinds of hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  18. Standard test methods for performance characteristics of metallic bonded resistance strain gages

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1992-01-01

    1.1 The purpose of this standard is to provide uniform test methods for the determination of strain gauge performance characteristics. Suggested testing equipment designs are included. 1.2 Test Methods E 251 describes methods and procedures for determining five strain gauge parameters: Section Part I—General Requirements 7 Part II—Resistance at a Reference Temperature 8 Part III—Gauge Factor at a Reference Temperature 9 Part IV—Temperature Coefficient of Gauge Factor\t10 Part V—Transverse Sensitivity\t11 Part VI—Thermal Output\t12 1.3 Strain gauges are very sensitive devices with essentially infinite resolution. Their response to strain, however, is low and great care must be exercised in their use. The performance characteristics identified by these test methods must be known to an acceptable accuracy to obtain meaningful results in field applications. 1.3.1 Strain gauge resistance is used to balance instrumentation circuits and to provide a reference value for measurements since all data are...

  19. Effects of crude glycerin on performance and carcass characteristics of finishing wether lambs.

    Science.gov (United States)

    Gunn, P J; Neary, M K; Lemenager, R P; Lake, S L

    2010-05-01

    The objective of this study was to evaluate the effects of crude glycerin on performance and carcass characteristics in finishing wether lambs. Thirty black-faced, Suffolk-cross wether lambs (44.1 +/- 5.6 kg initial BW) were stratified and blocked by BW to 1 of 5 individually fed, isocaloric, isonitrogenous dietary treatments containing 0, 5, 10, 15, or 20% crude glycerin (88% pure) on a DM basis. Diets were fed once daily for ad libitum consumption and contained 15% chopped hay, approximately 25% dried distillers grains with solubles, and the specified treatment combination of cracked corn replaced with increasing amounts of crude glycerin. Wethers were weighed on 14-d intervals and were selected for slaughter when they reached an approximate 12th-rib fat depth of 0.51 cm (28 to 84 d on trial). Carcass characteristics were collected after a 48-h chill. Dry matter intake (linear, P = 0.004) and ADG (quadratic, P = 0.05) increased with increasing concentrations of glycerin in the diet during the first 14 d of the feeding period. Similarly, G:F tended to increase quadratically (P = 0.06) with increasing concentrations of crude glycerin in the diet during the first 14 d. However, there were no differences among treatments for final BW, days on feed, or cumulative DMI, cumulative ADG, and cumulative G:F (P >or= 0.11). Body wall thickness, dressing percent, HCW, LM area, flank streaking, leg score, conformation score, quality grade, yield grade, and percent boneless, closely trimmed retail cuts did not differ (P >or= 0.21). Adding up to 15% crude glycerin to finishing wether diets improved feedlot performance, particularly during the first 14 d, without any concomitant effect on carcass characteristics.

  20. REGARDING "TRAGIC ECONOMIC OPTIMUM" FROM HOLISTIC+ PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Constantin Popescu

    2010-12-01

    Full Text Available Communication aims to discuss the new scientific vision of "the entire integrated" as it follows the recent achievements of quantum physics, psychology and biology. From this perspective, economy is seen as a living organism, part of the social organism and together with de bright ecology. The optimum of the economy as a living organism is based on dynamic compatibilities with all common living requirements. The evolution of economic life is organically linked to the unavoidable circumstances contained in the form of V. Frankl ‘s tragic triad consisting of: pain, guilt and death. In interaction with the holistic triad circumscribed by limitations, uncertainties and open interdependencies, the tragic economic optimum (TEO is formed. It can be understood as that state of economic life in which freedom of choice of scarce resources under uncertainty has in the compatibility of rationality and hope the development criteria of MEANING. TEO means to say YES to economic life even in conditions of resource limitations, bankruptcies and unemployment, negative externalities, stress, etc. By respiritualization of responsibility using scientific knowledge. TEO - involves multicriteria modeling of economic life by integrating human demands, community, environmental, spiritual and business development in the assessment predicting human GDP as a variable wave aggregate.

  1. Indoor temperatures for optimum thermal comfort and human performance

    DEFF Research Database (Denmark)

    de Dear, R.; Arens, E. A.; Candido, C.;

    2014-01-01

    A response by R. J. de Dear et al to a letter to the editor in response to their article "Progress in thermal comfort research over the last 20 years," published in a 2013 issue.......A response by R. J. de Dear et al to a letter to the editor in response to their article "Progress in thermal comfort research over the last 20 years," published in a 2013 issue....

  2. Combustion Characteristics and Propulsive Performance of Boron/Ammonium Perchlorate Mixtures in Microtubes

    Science.gov (United States)

    Liang, Daolun; Liu, Jianzhong; Zhou, Junhu; Wang, Yang; Yang, Yuxin

    2016-07-01

    A microthruster is used for the operation tracking and posture control of microsatellites. In this work, the combustion characteristics and propulsive performance of a boron/ammonium perchlorate (B/AP) propellant mixture for a microthruster were investigated. Amorphous B and AP were used in different mass ratios to prepare the propellant samples. A laser-ignition solid micropropulsion test system was set up, and a differential scanning calorimeter was used. The solid combustion products of the samples with good performance were collected. Microstructural and component analyses of the combustion products were performed. Various performance parameters, including the combustion temperature, combustion velocity, spectral intensity, ignition delay time, thrust, specific impulse, density specific impulse, and heat flow, changed with the fuel-oxidant ratio. The optimal fuel-oxidant mass ratio of the propellant samples was 40%, with a density specific impulse of 0.474 kg/m2•s and a maximum heat flow of 4.4913 mW/mg. Analysis of the combustion products revealed that the clearance between particles significantly diminished after combustion. During combustion, the AP completely decomposed, and a large amount of H3BO3, B2O3, and HBO2 was generated.

  3. Board Characteristics and Firm Performance: Evidence from Indonesia (137-154

    Directory of Open Access Journals (Sweden)

    Athalia Ariati Hidayat

    2017-01-01

    Full Text Available This research examines the effect of board characteristics (comprising in different sized proportions: family commissioners, family directors, independent commissioners, ex-government officer commissioners, and board of commissioners size to firm performance. Using fixed-effects data panel regression, this research investigates 293 firms listed on the Indonesian Stock Exchange during 2008-2012. Firm performance is proxied by market measure (Tobin’s Q and accounting measure (ROA. The findings of this research suggest that the proportion of family commissioners and family directors have positive impact only to Tobin’s Q value, while the proportion of independent directors can increase both Tobin’s Q and ROA. On the other hand, this research finds that the proportion of ex-government officers in the board gives no impact to firm performance. This research also finds that the board size has U-shaped non-linear relationship with firm performance as proxied by Tobin’s Q and ROA.Keywords: board of commissioners size, ex-government officer commissioner, family commissioner, family director, independent commissioner

  4. Application of the Brixton spatial anticipation test in stroke: ecological validity and performance characteristics.

    Science.gov (United States)

    Vordenberg, Jessica A; Barrett, John J; Doninger, Nicholas A; Contardo, Christopher P; Ozoude, Kingsley A

    2014-01-01

    Executive dysfunction predicts functional recovery post-stroke. However, traditional neuropsychological tests have limitations with this population due to required verbal response, complex motor response, and lengthy administration time. This study examined the ecological validity and performance characteristics of a relatively new measure of executive function, the Brixton Spatial Anticipation Test, which does not place the aforementioned demands on these patients. A total of 57 ischemic stroke patients with frontal lobe and subcortical lesions were administered the Brixton, on average 2 weeks post-stroke, during inpatient rehabilitation and assessed using the Functional Independence Measure (FIM) upon discharge. Brixton performance was significantly correlated with the FIM Total and FIM Cognitive Subtotal at discharge but unrelated to FIM Motor Subtotal. After controlling for global ability measured by the RBANS, Brixton performance accounted for additional variance in predicting FIM Total score at discharge. Interestingly, patients with subcortical strokes in the thalamus and basal ganglia performed significantly worse than patients with strokes in the frontal cortex on the Brixton, supporting the role of subcortical structures in the frontal lobe circuitry and executive function. Based on the present findings, the Brixton is a sensitive measure conducive to the stroke population and has strong ecological validity for identifying cognitive functional outcomes post-stroke.

  5. Survival analysis: A consumer-friendly method to estimate the optimum sucrose level in probiotic petit suisse.

    Science.gov (United States)

    Esmerino, E A; Paixão, J A; Cruz, A G; Garitta, L; Hough, G; Bolini, H M A

    2015-11-01

    For years, just-about-right (JAR) scales have been among the most used techniques to obtain sensory information about consumer perception, but recently, some researchers have harshly criticized the technique. The present study aimed to apply survival analysis to estimate the optimum sucrose concentration in probiotic petit suisse cheese and compare the survival analysis to JAR scales to verify which technique more accurately predicted the optimum sucrose concentration according to consumer acceptability. Two panels of consumers (total=170) performed affective tests to determine the optimal concentration of sucrose in probiotic petit suisse using 2 different methods of analysis: JAR scales (n=85) and survival analysis (n=85). Then an acceptance test was conducted using naïve consumers (n=100) between 18 and 60 yr old, with 2 samples of petit suisse, one with the ideal sucrose determined by JAR scales and the other with the ideal sucrose content determined by survival analysis, to determine which formulation was in accordance with consumer acceptability. The results indicate that the 2 sensory methods were equally effective in predicting the optimum sucrose level in probiotic petit suisse cheese, and no significant differences were detected in any of the characteristics related to liking evaluated. However, survival analysis has important advantages over the JAR scales. Survival analysis has shown the potential to be an advantageous tool for dairy companies because it was able to accurately predict the optimum sucrose content in a consumer-friendly way and was also practical for researchers because experimental sensory work is simpler and has been shown to be more cost effective than JAR scales without losses of consumer acceptability.

  6. Characteristics of Providers Performing Urogynecologic Procedures on Medicare Patients 2012-2014.

    Science.gov (United States)

    Stone, Daniel E; Barenberg, Benjamin J; Pickett, Stephanie D; OʼLeary, Dena E; Quiroz, Lieschen H

    To analyze the characteristics of providers performing stress urinary incontinence (SUI) and pelvic organ prolapse (POP) procedures in the United States. The Centers for Medicare Services public database, released for years 2012 through 2014, was queried for SUI-related and POP-related Healthcare Common Procedure Coding System. Providers were categorized as Female Pelvic Medicine and Reconstructive Surgery (FPMRS) providers and non-FPMRS providers, using a list of FPMRS board-certified providers compiled through the American Board of Medical Subspecialties website. Other physician specialties that submitted SUI and POP procedures claims were tabulated. Six hundred twenty-nine FPMRS and 833 non-FPMRS providers submitted claims for SUI and POP procedures. The SUI procedures claims had the following provider specialty distribution: obstetrics and gynecology (OB/GYN)-FPMRS, 46.7%; urology, 26.3%; OB/GYN, 12.2%; and urology-FPMRS, 13.9%, with the remaining 0.9% being performed by other specialties. The POP procedures had the following specialty distribution: OB/GYN-FPMRS, 63.4%; OB/GYN, 16.7%; urology, 8.3%; and urology-FPMRS, 7.1%, with the remaining 4.5% being performed by other specialties.Provider distribution was compared between transvaginal mesh and sling insertion procedures to transvaginal mesh and sling removal procedures. The FPMRS providers claimed 63.6% of sling and transvaginal mesh insertion procedures and performed 84.9% of mesh and sling removal procedures. Medicare reimbursement data provides a unique insight into the distribution of provider specialties performing SUI-related and POP-related procedures in the Medicare population. The OB/GYN-FPMRS providers submitted the majority of claims for SUI and POP procedures from 2012 to 2014. The FPMRS providers are also performing the majority of mesh removal procedures.

  7. Performance characteristics of retrograde single-balloon endoscopy: A single center experience

    Institute of Scientific and Technical Information of China (English)

    Kaci E Christian; Karan Kapoor; Eric M Goldberg

    2016-01-01

    AIM: To evaluate the technical success, diagnostic yield(DY) and therapeutic potential of retrograde single balloon enteroscopy(rS BE). METHODS: A retrospective review of 136 rS BE procedures performed at a tertiary academic referral center from January 2006 and September 2013 was completed. Patient characteristics including age, gender and inpatient status were collected. The indication for the procedure was categorized into one of three groups: Obscure gastrointestinal bleeding(GIB), evaluation for Crohn’s disease and abnormal imaging. Procedural characteristics including insertion depth(ID), procedure time, concordance with pre-procedural imaging and complications were also recorded. Lastly, DY, defined as the percentage of cases producing either a definitive diagnosis or findings that could explain clinical symptoms and therapeutic yield(TY), defined as the percentage of cases in which a definitive intervention was performed, were determined. Mucosal tattooing and biopsy alone were not included in the TY. RESULTS: A total of 136 rS BE procedures were identified. Mean patient age was 57.5(± 16.2) years, 67(49.2%) were male, and 110(80.9%) procedures were performed on an outpatient basis. Indications for rS BE included GIB in 55(40.4%), evaluation of inflammatory bowel disease(IBD) in 29(21.3%), and imaging suggestive of pathology other than GIB or IBD in 43(31.6%). Nine(6.6%) rS BEs were performed for other indications. Mean ID was 68.3(± 39.3) cm proximal to the ileocecal valve and mean time to completion was 41.7(± 15.5) min. Overall, 73(53.7%) cases were diagnostic and 25(18.4%) cases were therapeutic in which interventions(argon plasma coagulation, stricture dilatation, polypectomy, etc.) were performed. Pre-procedural imaging was performed in 88(64.7%) patients. Endoscopic concordance of positive imaging findings was seen in 31(35.2%) cases. Follow up data was available in 93(68.4%) patients; 2(2.2%) reported post-procedural abdominal pain within 30 d

  8. Linseed, microalgae or fish oil dietary supplementation affects performance and quality characteristics of light lambs

    Directory of Open Access Journals (Sweden)

    Jesus de la Fuente-Vazquez

    2014-05-01

    Full Text Available The aim of this work was to improve the fatty acid profile of meat from light lamb, frequently reared in Spain and in other Mediterranean countries. A total of 44 light lambs fed different n-3 polyunsaturated fatty acids sources were studied: control (C (palm oil, extruded linseed (L, extruded linseed mixed with microalgae (LM and fish oil (FO. The productive performance from 14.7 to 26.2 kg of live weights and meat quality characteristics during refrigerated storage were assessed. Lambs fed FO showed lower feed intake (p <0.001, average daily gain (p <0.001 and higher feed conversion ratio (p <0.001 than lambs from the other treatments. Fish oil meat had the lowest (p <0.01 protein proportion and the highest (p <0.001 C20:5n-3, C22:5n-3 and C22:6n-3 proportions, while L or LM produced the highest (p <0.001 C18:3n-3 deposition. Fish oil meat had higher (p <0.05 L* and lower (p <0.001 a* than meats from the other treatments. After 7 days of storage, FO meat showed the highest TBARS (p <0.001, while C meat showed similar value to 0 days of storage. Additionally, FO underwent higher microbial growth after 7 days of storage as compared to the other treatments. Dietary supplementation with L and LM leads to C18:3n-3 meat enrichment and to a microbial load and colour characteristics similar to those of C, without adverse effect on lamb performance. However the use of FO improves the fatty acid profile of meat, but negatively affects lamb performance and meat quality.

  9. Performance characteristics of single effect lithium bromide/ water absorption chiller for small data centers

    Science.gov (United States)

    Mysore, Abhishek Arun Babu

    A medium data center consists of servers performing operations such as file sharing, collaboration and email. There are a large number of small and medium data centers across the world which consume more energy and are less efficient when compared to large data center facilities of companies such as GOOGLE, APPLE and FACEBOOK. Such companies are making their data center facilities more environmental friendly by employing renewable energy solutions such as wind and solar to power the data center or in data center cooling. This not only reduces the carbon footprint significantly but also decreases the costs incurred over a period of time. Cooling of data center play a vital role in proper functioning of the servers. It is found that cooling consumes about 50% of the total power consumed by the data center. Traditional method of cooling includes the use of mechanical compression chillers which consume lot of power and is not desirable. In order to eliminate the use of mechanical compressor chillers renewable energy resources such as solar and wind should be employed. One such technology is solar thermal cooling by means of absorption chiller which is powered by solar energy. The absorption chiller unit can be coupled with either flat plate or evacuated tube collectors in order to achieve the required inlet temperature for the generator of the absorption chiller unit. In this study a modular data center is considered having a cooling load requirement of 23kw. The performance characteristics of a single stage Lithium Bromide/ water refrigeration is presented in this study considering the cooling load of 23kw. Performance characteristics of each of the 4 heat exchangers within the unit is discussed which helps in customizing the unit according to the users' specific needs. This analysis helps in studying the importance of different properties such as the effect of inlet temperatures of hot water for generator, inlet temperatures of cooling water for absorber and

  10. Effects of dietary crude protein on the growth performance, carcass characteristics and serum biochemical indexes of Lueyang black-boned chickens from seven to twelve weeks of age

    Directory of Open Access Journals (Sweden)

    SK Liu

    2015-03-01

    Full Text Available This study was undertaken to assess dietary crude protein (CP concentration for optimum growth performance and carcass characteristics of Lueyang black-boned chicken. In total, six hundred 42-day-old Lueyang black-boned chicks were randomly assigned to five treatments, each with six replicate pens with ten males and ten females. The birds fed experimental diets with different levels of protein concentration of 120, 140, 160, 180 and 200 g kg-1 from seven to twelve weeks of age respectively. On day of 84, weight gain, feed intake, and feed:gain ratio were measured, and two chickens (one male and one female close to the average weight of all birds in each treatment were selected from each pen and sacrificed to evaluate carcass traits and selected serum biochemical indexes. Dietary CP concentration did not have any significant influence on feed intake (p>0.05. The birds fed the diet with 180 or 160 g kg-1 CP concentration exhibited greater (p<0.05 growth rate, better feed conversion ratio, relative breast weight and albumin concentration in serum than that of those fed other dietary CP concentrations. According to the results of regression analysis, the CP requirements of Lueyang black-boned chicken from seven to twelve weeks of age for optimal weight gain and feed:gain ratio were 174 and 170 g kg-1, respectively.

  11. Effects of the standardized ileal digestible lysine to metabolizable energy ratio on performance and carcass characteristics of growing-finishing pigs

    Directory of Open Access Journals (Sweden)

    Li Pengfei

    2012-03-01

    Full Text Available Abstract A total of 2,121 growing-finishing pigs (Duroc × Landrace × Large White were utilized in six experiments conducted to determine the effects of different ratios of standardized ileal digestible lysine (SID-Lys to metabolizable energy (ME on the performance and carcass characteristics of growing-finishing pigs. Exps. 1 (30 to 50 kg, 2 (52 to 70 kg and 3 (81 to 104 kg were conducted to find an optimum ME level and then this level was used in Exps. 4 (29 to 47 kg, 5 (54 to 76 kg and 6 (84 to 109 kg to test the response of pigs to different ratios of SID-Lys:ME. In Exps.1 to 3, four treatments were used consisting of diets with a formulated ME content of 3.1, 3.2, 3.3 or 3.4 in Exps. 1 and 2 while Exp. 3 used 3.05, 3.15, 3.25 or 3.35 Mcal/kg. A constant SID-Lys:ME ratio of 2.6, 2.3 or 2.0 g/Mcal was used in Exps. 1, 2 and 3, respectively. Weight gain was significantly increased with increasing energy level in Exp.1 while weight gain was unaltered in Exps. 2 and 3. For all three experiments, feed intake was decreased (P P P P P P

  12. Heat transfer and performance characteristics of axial cooling fans with downstream guide vanes

    Science.gov (United States)

    Terzis, Alexandros; Stylianou, Ioannis; Kalfas, Anestis I.; Ott, Peter

    2012-04-01

    This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.

  13. Prebiotic and antimicrobials on performance, carcass characteristics, and antibody production in broilers

    Directory of Open Access Journals (Sweden)

    Maíra Fomentini

    2016-06-01

    Full Text Available ABSTRACT: To evaluate the effect of supplementation with mannan oligosaccharides, avilamycin and halquinol, alone or in combination, on the performance, carcass characteristics and antibody production in broilers (1-49 days old, male broiler chicks (n=1440; Cobb 500; one day old were housed and distributed into a completely randomized design into six treatments (eight replicates; 30 animals per pen. To produce the experimental diets, three types of performance enhancer additives were used. Halquinol (HAL, avilamycin (AVI and mannan oligosaccharides (MOS were included (alone or in combination in the basal diet (instead of corn starch. Effects of diet were observed on results of animal performance in the period 1-21 and 1-42 days old. Broilers fed with a diet without growth promoter showed lower weight gain in relation to those fed with diets with antimicrobials, MOS or a combination of them. In the period 1-49 days old, feed conversion increased in broilers fed with rations without promoter. At the end of the experimental period no influence of diets was observed on the carcass yield and cuts, and titles of specific antibodies to avian infectious bronchitis. The use of MOS and/or antimicrobials (AVI or HAL, alone or in combination, improves feed conversion of broilers reared until 49 days of age.

  14. PERFORMANCE AND EMISSION CHARACTERISTICS OF A CI ENGINE OPERATED ON VEGETABLE OILS AS ALTERNATIVE FUELS

    Directory of Open Access Journals (Sweden)

    K. Rajagopal

    2011-12-01

    Full Text Available An experimental analysis was done using a four-stroke, single cylinder, constant speed, water-cooled diesel engine, which was interfaced with Engine software. Performance and emission characteristics were evaluated for three non-edible vegetable oils, i.e. thumba, jojoba, neem oil, as well as jojoba methyl ester, to study the effect of injection pressure at 205, 220, 240 and 260 bar with a variation in injection timing at 23°bTDC and 28°bTDC. The performance of jojoba methyl ester improved with an increase in injection pressure. A maximum brake thermal efficiency of 29.72% was obtained with lower emissions compared to the other vegetable oils; this might be explained by low viscosity and better combustion. Further investigations were carried out with a new lubricant, SAE 5W-30, which improved the performance of the CI engine by 1.59%. All of the abovementioned investigations were fruitful and these results are expected to lead to substantial contributions in the development of a viable vegetable oil engine.

  15. Performance characteristic of a Stirling refrigeration cycle in micro/nano scale

    Science.gov (United States)

    Nie, Wenjie; He, Jizhou; Du, Jianqiang

    2009-02-01

    The aim of the paper is to present the performance characteristics of a Stirling refrigeration cycle in micro/nano scale, in which the working substance of cycle is an ideal Maxwellian gas. Due to the quantum boundary effect on the gas particles confined in the finite domain, the cycle no longer possesses the condition of perfect regeneration. The inherent regenerative losses, the refrigeration heat and coefficient of performance (COP) of the cycle are derived. It is found that, for the micro/nano scaled Stirling refrigeration cycle devices, the refrigeration heat and COP of cycle all depend on the surface area of the system (boundary of cycle) besides the temperature of the heat reservoirs, the volume of system and other parameters, while for the macro scaled refrigeration cycle devices, the refrigeration heat and COP of cycle are independent of the surface area of the system. Variations of the refrigeration heat ratio rR and the COP ratio rε with the temperature ratio τ and volume ratio rV for the different surface area ratio rA are examined, which reveals the influence of the boundary of cycle on the performance of a micro/nano scaled Stirling refrigeration cycle. The results are useful for designing of a micro/nano scaled Stirling cycle device and may conduce to confirming experimentally the quantum boundary effect in the micro/nano scaled devices.

  16. Morphological characteristics of adult male handball players considering five levels of performance and playing position.

    Science.gov (United States)

    Massuça, Luís; Fragoso, Isabel

    2015-03-01

    This study aims 1--to describe and compare the anthropometric characteristics of male handball players from different levels of performance, and 2--to identify the morphological variables that allow differentiation of the level of performance for each individual playing position. A total of 212 male handball players (age, 23.6 ± 5.2 years) were included in this study, and divided into five levels of performance for comparison. The playing position of each player was recorded. All participants were tested during the 2008-2009 Portuguese handball season. Twenty-eight anthropometric measures were taken by a group of anthropometrics accredited by International Society of the Advance of Kinanthropometry. Body composition, fat mass and muscle mass were calculated from the equations proposed by Faulkner26, Yuhase28, Durnin and Womersley25, Jackson and Pollock29, Matiegka33, Heymsfield, McManus, Smith, Stevens and Nixon34, Martin, Spenst, Drinkwater and Clarys21, Doupe, Martin, Searle, Kriellaars and Giesbrecht35 and Lee, Wang, Heo, Ross, Janssen and Heymsfield36. The research findings showed that the morphological optimization is important to have success in handball.

  17. Towards the Optimum Light Source Spectrum

    Directory of Open Access Journals (Sweden)

    Andrew Chalmers

    2010-01-01

    Full Text Available This paper is concerned with designing light source spectra for optimum luminous efficacy and colour rendering. We demonstrate that it is possible to design light sources that can provide both good colour rendering and high luminous efficacy by combining the outputs of a number of narrowband spectral constituents. Also, the achievable results depend on the numbers and wavelengths of the different spectral bands utilized in the mixture. Practical realization of these concepts has been demonstrated in this pilot study which combines a number of simulations with tests using real LEDs (light emitting diodes. Such sources are capable of providing highly efficient lighting systems with good energy conservation potential. Further research is underway to investigate the practicalities of our proposals in relation to large-scale light source production.

  18. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.;

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

  19. Choosing an optimum sand control method

    Directory of Open Access Journals (Sweden)

    Ehsan Khamehchi

    2015-06-01

    Full Text Available Formation sand control is always one of the main concerns of production engineers. There are some different methods to prevent sand production. Choosing a method for preventing formation sand production depends on different reservoir parameters and politic and economic conditions. Sometimes, economic and politic conditions are more effective to choose an optimum than reservoir parameters. Often, simultaneous investigation of politic and economic conditions with reservoir parameters has different results with what is expected. So, choosing the best sand control method is the result of thorough study. Global oil price, duration of sand control project and costs of necessary equipment for each method as economic and politic conditions and well productivity index as reservoir parameter are the main parameters studied in this paper.

  20. Optimum conditions for microbial carbonate precipitation.

    Science.gov (United States)

    Okwadha, George D O; Li, Jin

    2010-11-01

    The type of bacteria, bacterial cell concentration, initial urea concentration, reaction temperature, the initial Ca(2+) concentration, ionic strength, and the pH of the media are some factors that control the activity of the urease enzyme, and may have a significant impact on microbial carbonate precipitation (MCP). Factorial experiments were designed based on these factors to determine the optimum conditions that take into consideration economic advantage while at the same time giving quality results. Sporosarcina pasteurii strain ATCC 11859 was used at constant temperature (25°C) and ionic strength with varying amounts of urea, Ca(2+), and bacterial cell concentration. The results indicate that the rate of ureolysis (k(urea)) increases with bacterial cell concentration, and the bacterial cell concentration had a greater influence on k(urea) than initial urea concentration. At 25 mM Ca(2+) concentration, increasing bacterial cell concentration from 10(6) to 10(8)cells mL⁻¹ increased the CaCO(3) precipitated and CO(2) sequestrated by over 30%. However, when the Ca(2+) concentration was increased 10-fold to 250 mM Ca(2+), the amount of CaCO(3) precipitated and CO(2) sequestrated increased by over 100% irrespective of initial urea concentration. Consequently, the optimum conditions for MCP under our experimental conditions were 666 mM urea and 250 mM Ca(2+) at 2.3×10⁸ cells mL⁻¹ bacterial cell concentration. However, a greater CaCO(3) deposition is achievable with higher concentrations of urea, Ca(2+), and bacterial cells so long as the respective quantities are within their economic advantage. X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray analyzes confirmed that the precipitate formed was CaCO(3) and composed of predominantly calcite crystals with little vaterite crystals.

  1. Analysis of Thermal Performance in a Bidirectional Thermocycler by Including Thermal Contact Characteristics

    Directory of Open Access Journals (Sweden)

    Jyh Jian Chen

    2014-12-01

    Full Text Available This paper illustrates an application of a technique for predicting the thermal characteristics of a bidirectional thermocycling device for polymerase chain reaction (PCR. The micromilling chamber is oscillated by a servo motor and contacted with different isothermal heating blocks to successfully amplify the DNA templates. Because a comprehensive database of contact resistance factors does not exist, it causes researchers to not take thermal contact resistance into consideration at all. We are motivated to accurately determine the thermal characteristics of the reaction chamber with thermal contact effects existing between the heater surface and the chamber surface. Numerical results show that the thermal contact effects between the heating blocks and the reaction chamber dominate the temperature variations and the ramping rates inside the PCR chamber. However, the influences of various temperatures of the ambient conditions on the sample temperature during three PCR steps can be negligible. The experimental temperature profiles are compared well with the numerical simulations by considering the thermal contact conductance coefficient which is empirical by the experimental fitting. To take thermal contact conductance coefficients into consideration in the thermal simulation is recommended to predict a reasonable temperature profile of the reaction chamber during various thermal cycling processes. Finally, the PCR experiments present that Hygromycin B DNA templates are amplified successfully. Furthermore, our group is the first group to introduce the thermal contact effect into theoretical study that has been applied to the design of a PCR device, and to perform the PCR process in a bidirectional thermocycler.

  2. Influence of Early Quantitative Feed Restriction on Performance and Carcass Characteristics of Broiler Chickens

    Institute of Scientific and Technical Information of China (English)

    SHI Baoming; SHAN Anshan; CHAN Long

    2006-01-01

    An experiment was conducted to study the influence of early quantitative feed restriction on the performance and carcass characteristics of broiler chickens. Two hundred 8-day-old commercial Avian male broiler chicks were assigned to four groups randomly, with 50 broilers each. At the age of 8 days the broilers were restricted to 90%, 80% or 70% of the ad libitum intake for 7 days. When the restricion was finished, all birds received feed ad libitum again. The results showed that diet restriction resulted in a reduction in body weight and daily gain during the restriction period (P <0.05). The birds restricted to 90% of the ad libitum intake showed the occurring of growth compensation in the 3rd week. The birds restricted to 80% and 70% of the ad libitum intake had growth compensation in the 4th week. No significant differences between the effects of the restriction and the control on final body weight,growth rate, feed conversion efficiency and carcass characteristics (P >0.05).

  3. Heat Transfer Characteristics and Performance of a Spirally Coiled Heat Exchanger under Sensible Cooling Conditions

    Science.gov (United States)

    Wongwises, Somchai; Naphon, Paisarn

    In the present study, new experimental data on the heat transfer characteristics and the performance of a spirally coiled heat exchanger under sensible cooling conditions is presented. The spiral-coil heat exchanger consists of a steel shell and a spirally coiled tube unit. The spiral-coil unit consists of six layers of concentric spirally coiled tubes. Each tube is fabricated by bending a 9.27mm diameter straight copper tube into a spiral-coil of five turns. The innermost and outermost diameters of each spiral-coil are 67.7 and 227.6mm, respectively. Air and water are used as working fluids in shell side and tube side, respectively. A mathematical model based on the conservation of energy is developed to determine the heat transfer characteristics. There is a reasonable agreement between the results obtained from the experiment and those obtained from the model and a good agreement for the high air mass flow rate region. The results obtained from the parametric study are also discussed.

  4. Effect of rearing system and season on the performance and egg characteristics of Ancona laying hens

    Directory of Open Access Journals (Sweden)

    Cesare Castellini

    2010-01-01

    Full Text Available Productive performance and egg characteristics of Ancona laying hens reared under three different rearing systems (conventional, organic and organic-plus were compared during an experimental period of one year. Three-hundred-sixty Ancona female chicks at 28 days of age were divided in three groups and assigned to different rearing systems. The organic group had 4m2 pasture/hen according to the requirements imposed by the EC Regulation 1804/99, whereas the organic-plus group had a larger grass paddock (10m2/hen. The Control group was reared in cages under standard housing conditions. The following egg characteristics were recorded and analysed during the year-long cycle: egg weight and egg mass laid/d, weight of egg components, shell thickness, Haugh index and yolk colour. Egg quality was affected by the pasture available. The hens that ingested grass (organic-plus, produced eggs with higher shell weight and percentage, darker yolk colour and higher α-tocopherol, carotenoid and polyphenol contents. The other egg traits were not affected by rearing system.

  5. STUDY OF PERFORMANCE CHARACTERISTICS OF VARIABLE COMPRESSION RATIO DIESEL ENGINE USING ETHANOL BLENDS WITH DIESEL

    Directory of Open Access Journals (Sweden)

    NILESH MOHITE

    2012-06-01

    Full Text Available As the population of the world increases consumption of the energy also increases tremendously. With the current consumption rate if it has been quoted that there will be great shortage of petroleum products in upcoming decades, it will not be wrong. For this reason people are looking for alternative fuels. As ethanol is the main bio-product in the many industries now-a-days, it is better to develop the engine which can work on pure ethanol or one can add ethanol in the petrol or diesel and use the blends of that. For this purpose, it is necessary to check the performance characteristics and emissions of the blends of ethanol and also necessary to compare with the pure form of fuels. Again it is necessary to check the effect of compression ratio on the blends of ethanol. So in this paper the same has been conducted at basic level.

  6. Performance characteristics of white light sources consisting of multiple light-emitting diodes

    Science.gov (United States)

    Li, Yun-Li; Shah, Jay M.; Leung, P.-H.; Gessmann, Thomas; Schubert, E. F.

    2004-01-01

    The performance characteristics of white light sources based on a multiple-LED approach, in particular dichromatic and trichromatic sources are analyzed in detail. Figures of merit such as the luminous efficacy, color temperature, and color rendering capabilities are provided for a wide range of primary emission wavelengths. Spectral power density functions of LEDs are assumed to be thermally and inhomogeneously broadened to a full width at half maximum of several kT, in agreement with experimental results. A gaussian line shape is assumed for each of the emission bands. It is shown that multi-LED white light sources have the potential for luminous efficacies greater than 400 lm/W (dichromatic source) and color rendering indices of greater than 90 (trichromatic source). Contour maps for the color rendering indices and luminous efficacies versus three wavelengths are given.

  7. Estimation of Characteristics of a Software Team for Implementing Effective Inspection Process through Inspection Performance Metric

    CERN Document Server

    Nair, T R Gopalakrishnan

    2011-01-01

    The continued existence of any software industry depends on its capability to develop nearly zero-defect product, which is achievable through effective defect management. Inspection has proven to be one of the promising techniques of defect management. Introductions of metrics like, Depth of Inspection (DI, a process metric) and Inspection Performance Metric (IPM, a people metric) enable one to have an appropriate measurement of inspection technique. This article elucidates a mathematical approach to estimate the IPM value without depending on shop floor defect count at every time. By applying multiple linear regression models, a set of characteristic coefficients of the team is evaluated. These coefficients are calculated from the empirical projects that are sampled from the teams of product-based and service-based IT industries. A sample of three verification projects indicates a close match between the IPM values obtained from the defect count (IPMdc) and IPM values obtained using the team coefficients usi...

  8. High performance and transparent multilayer MoS2 transistors: Tuning Schottky barrier characteristics

    Directory of Open Access Journals (Sweden)

    Young Ki Hong

    2016-05-01

    Full Text Available Various strategies and mechanisms have been suggested for investigating a Schottky contact behavior in molybdenum disulfide (MoS2 thin-film transistor (TFT, which are still in much debate and controversy. As one of promising breakthrough for transparent electronics with a high device performance, we have realized MoS2 TFTs with source/drain electrodes consisting of transparent bi-layers of a conducting oxide over a thin film of low work function metal. Intercalation of a low work function metal layer, such as aluminum, between MoS2 and transparent source/drain electrodes makes it possible to optimize the Schottky contact characteristics, resulting in about 24-fold and 3 orders of magnitude enhancement of the field-effect mobility and on-off current ratio, respectively, as well as transmittance of 87.4 % in the visible wavelength range.

  9. Preparation, characterisation, engine performance and emission characteristics of coconut oil based hybrid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pranil J.; Singh, Anirudh [Division of Physics, School of Engineering and Physics, Faculty of Science, Technology and Environment, University of the South Pacific, 325 Fletcher Road, Suva (Fiji); Khurma, Jagjit [Division of Chemistry, School of Biological, Chemical and Environmental Sciences, Faculty of Science, Technology and Environment, University of the South Pacific, Suva (Fiji)

    2010-09-15

    In this study, hybrid fuels consisting of coconut oil, aqueous ethanol and a surfactant (butan-1-ol) were prepared and tested as a fuel in a direct injection diesel engine. After determining fuel properties such as the density, viscosity and gross calorific values of these fuels, they were used to run a diesel engine. The engine performance and exhaust emissions were investigated and compared with that of diesel. The experimental results show that the efficiency of the hybrid fuels is comparable to that of diesel. As the viscosity of the hybrid fuels decreased and approached that of diesel, the efficiency increased progressively towards that of diesel. The exhaust emissions were lower than those for diesel, except carbon monoxide emissions, which increased. Hence, it is concluded that these hybrid fuels can be used successfully as an alternative fuel in diesel engines without any modifications. Their completely renewable nature ensures that they are environmentally friendly with regard to their emissions characteristics. (author)

  10. A characteristics study on the performance of a two-stage light gas gun

    Institute of Scientific and Technical Information of China (English)

    吴应湘; 郑之初; P.Kupschus

    1995-01-01

    In order to obtain an overall and systematic understanding of the performance of a two-stage light gas gun (TLGG), a numerical code to simulate the process occurring in a gun shot is advanced based on the quasi-one-dimensional unsteady equations of motion with the real gas effect, friction and heat transfer taken into account in a characteristic formulation for both driver and propellant gas. Comparisons of projectile velocities and projectile pressures along the barrel with experimental results from JET (Joint European Torus) and with computational data got by the Lagrangian method indicate that this code can provide results with good accuracy over a wide range of gun geometry and loading conditions.

  11. An Online Premium? Characteristics and Performance of Online versus Face-to-Face Students in Principles of Microeconomics

    Science.gov (United States)

    Dendir, Seife

    2016-01-01

    The author uses data from two Principles of Microeconomics courses to examine differences in characteristics and performance of online versus face-to-face students. The analysis indicates that even in a traditional institution, the two delivery modes may be serving students with distinctly different backgrounds and characteristics. In terms of…

  12. Animal performance and meat characteristics in steers reared in intensive conditions fed with different vegetable oils.

    Science.gov (United States)

    Castro, T; Cabezas, A; De la Fuente, J; Isabel, B; Manso, T; Jimeno, V

    2016-03-01

    Enhancing the quality of beef meat is an important goal in terms of improving both the nutritional value for the consumer and the commercial value for producers. The aim of this work was to study the effects of different vegetable oil supplements on growth performance, carcass quality and meat quality in beef steers reared under intensive conditions. A total of 240 Blonde D' Aquitaine steers (average BW=293.7±38.88 kg) were grouped into 24 batches (10 steers/batch) and were randomly assigned to one of the three dietary treatments (eight batches per treatment), each supplemented with either 4% hydrogenated palm oil (PALM) or fatty acids (FAs) from olive oil (OLI) or soybean oil (SOY). No differences in growth performance or carcass quality were observed. For the meat quality analysis, a steer was randomly selected from each batch and the 6th rib on the left half of the carcass was dissected. PALM meat had the highest percentage of 16:0 (P<0.05) and the lowest n-6/n-3 polyunsaturated fatty acids (PUFA) ratio (P<0.05), OLI had the highest content of t11-18:1 (P<0.01) and c9,t11-18:2 (P<0.05) and SOY showed the lowest value of monounsaturated fatty acids (MUFA) (P<0.001), the highest percentage of PUFA (P<0.01) and a lower index of atherogenicity (P=0.07) than PALM. No significant differences in the sensory characteristics of the meat were noted. However, the results of the principal component analysis of meat characteristics enabled meat from those steers that consumed fatty acids from olive oil to be differentiated from that of steers that consumed soybean oil.

  13. Study of Gasohol as Alternative Fuel for Gasoline Substitution: Characteristics and Performances

    Directory of Open Access Journals (Sweden)

    Bardi Murachman

    2014-12-01

    Full Text Available Gasohol is a mixture of premium petrol (gasoline with alcohol, in this case ethanol. The use of gasohol can reduce fuel consumption without having to modify the existing engine. Therefore, this research is conducted to study the characteristics and performance of gasohol in various mixing ratios, which includes analysis of physical properties and the use of gasohol in the machine. Results show that the addition of technical ethanol at 7.0169%v increases the value of gasohol vapor pressure on the value of 8.6682 psi (7.7 psi for regular gasoline. Gasohol with technical ethanol content above 30%v decreases vapor pressure, promotes phase separation, and causes a sharp drop in temperature from 40%v distillation. In term of corrosivity, gasohol with up to 50%v ethanol content has the same corrosion level with regular gasoline, which is corrosion level 1A. Based on gasohol characteristics test, it is known that gasohol with technical ethanol content below 20%v can be used as a fuel substitute for gasoline. Real-time performance test of gasohol in engines has shown that the addition of ethanol content in gasohol tend to increase the engine power at a certain compression ratio, but it also increases fuel consumption because the heat value of ethanol is lower than gasoline. Machine in gasohol with ethanol content below 20%v can operate smoothly without having to modify the engine. Based on the studies that have been done, gasohol in the range of 10%v ethanol content is well-functioned as a substitute for gasoline fuel and meets fuel specifications required by the General Director of Oil and Gas. The feasibility of using gasohol as an alternative fuel can be studied further.

  14. CHARACTERISTICS OF PERFORMANCE AND EMISSIONS IN A DIRECT-INJECTION DIESEL ENGINE FUELLED WITH KEROSENE/DIESEL BLENDS

    National Research Council Canada - National Science Library

    K R Patil; S S Thipse

    2014-01-01

      An experimental investigation has been carried out to evaluate the effect of kerosene as an additive to diesel fuel on the combustion, performance and emission characteristics of a direct-injection...

  15. Effectiveness of oxygen enriched hydrogen-HHO gas addition on DI diesel engine performance, emission and combustion characteristics

    National Research Council Canada - National Science Library

    Premkartikkumar S.R; Annamalai K; Pradeepkumar A.R

    2014-01-01

    Nowadays, more researches focus on protecting the environment. Present investigation concern with the effectiveness of Oxygen Enriched hydrogen- HHO gas addition on performance, emission and combustion characteristics of a DI diesel engine...

  16. The Optimum Design of Hydrodynamic Lubrication Bearing for Minimization of the Total Life Cost

    Science.gov (United States)

    Iwatsubo, Takuzo; Yamabayashi, Jun

    This paper proposes an optimum design method of journal bearing for minimizing the total life cost which includes not only the initial cost but also the running cost. Journal bearing is one of the typical friction part and physically severe part in machine elements. Therefore, maintenance is required to prevent failure and to keep performance. For this object, the running cost by the maintenance is user's burden. Thus, the optimum design method of the bearing for minimization of the total life cost is required. In this research, the evaluation functions of the total life cost which contains the initial cost and the running cost of the bearing are discussed and the optimum design is proposed under the physical constrain, that is Thermo Hydrodynamic Lubrication theory (THL theory), and inequality constraints. Then design valuables of the optimum journal bearing are obtained.

  17. Optimum distribution of heat exchanger inventory for power density optimization of an endoreversible closed Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lingen Chen; Junlin Zheng; Fengrui Sun [Naval Univ. of Engineering, Faculty 306, Wuhan (China); Chih Wu [U.S. Naval Academy, Mechanical Engineering Dept., Annapolis, MD (United States)

    2001-02-07

    In this paper, the power density (defined as the ratio of the power output to the maximum specific volume in the cycle) is taken as the objective for performance optimisations of an endoreversible closed Brayton cycle coupled to constant-temperature heat reservoirs in the viewpoint of finite-time thermodynamics (FTT) or entropy generation minimisation (EGM). The optimum heat conductance distribution corresponding to the optimum power density of the hot- and cold-side heat exchangers for the fixed heat exchanger inventory is analysed using numerical examples. The influence of some design parameters on the optimum heat conductance distribution and the maximum power density and the optimum pressure ratio corresponding to the maximum power density are provided. The power plant design with optimisation leads to higher efficiency and smaller size. (Author)

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

    Science.gov (United States)

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

    2016-07-20

    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]O2max), power output at [Formula: see text]O2max (W[Formula: see text]O2max), peak power output (PPO), rowing economy and blood lactate indices and (3) seven-stroke power-output test to determine maximal power output (Wmax) and force (Fmax). 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% HRmax. 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]O2max (ES = 0.95, P = 0.035) and power output at lactate threshold (WLT) (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.

  19. Diffusion layer characteristics for increasing the performance of activated carbon air cathodes in microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2016-01-01

    The characteristics of several different types of diffusion layers were systematically examined to improve the performance of activated carbon air cathodes used in microbial fuel cells (MFCs). A diffusion layer of carbon black and polytetrafluoroethylene (CB + PTFE) that was pressed onto a stainless steel mesh current collector achieved the highest cathode performance. This cathode also had a high oxygen mass transfer coefficient and high water pressure tolerance (>2 m), and it had the highest current densities in abiotic chronoamperometry tests compared to cathodes with other diffusion layers. In MFC tests, this cathode also produced maximum power densities (1610 ± 90 mW m−2) that were greater than those of cathodes with other diffusion layers, by 19% compared to Gore-Tex (1350 ± 20 mW m−2), 22% for a cloth wipe with PDMS (1320 ± 70 mW m−2), 45% with plain PTFE (1110 ± 20 mW m−2), and 19% higher than those of cathodes made with a Pt catalyst and a PTFE diffusion layer (1350 ± 50 mW m−2). The highly porous diffusion layer structure of the CB + PTFE had a relatively high oxygen mass transfer coefficient (1.07 × 10−3 cm s−1) which enhanced oxygen transport to the catalyst. The addition of CB enhanced cathode performance by increasing the conductivity of the diffusion layer. Oxygen mass transfer coefficient, water pressure tolerance, and the addition of conductive particles were therefore critical features for achieving higher performance AC air cathodes.

  20. Fouling and thermal-performance characteristics of the Humboldt Bay Unit 2 power-plant condenser

    Energy Technology Data Exchange (ETDEWEB)

    Rabas, T.J. [Argonne National Lab., IL (United States); Elliott, E.S. [Pacific Gas and Electric Co., San Ramon, CA (US)

    1993-07-01

    An experimental program was conducted at the Humboldt Bay condenser using eight clusters of four neighboring tubes with different conditions. In each cluster, there were (1) a new tube, the tubeside fluid being distilled water; (2) a new tube, the tubeside fluid being plant circulating water (seawater) and no cleaning; (3) an old tube, plant circulating water with no cleaning; and (4) an old tube, plant circulating water with normal periodic manual cleaning (blowing plugs or sponge balls). These tube clusters were located at four different locations within both the first and second passes of this two-pass condenser. Because of the different conditions, the fouling and cleaning characteristics can be obtained with measurements of the flow rate and inlet, outlet, and saturation temperatures. In addition to the fouling data, the thermal performance can be compared to that obtained with the standard rating method. There was a reduction in the thermal performance of the new, distilled-water tubes for about the first 80 days, and then the performance remained essentially constant. This performance change was most likely the result of the change from dropwise to filmwise condensation on the 7/8-in OD, 18 BWG Admiralty tubes. There was a continued increase of the tubeside fouling resistance with time (no asymptotic behavior) for the tubes that were not cleaned in each cluster using the plant circulating water. The fouling rates were somewhat larger for the first or lower temperature pass initially for the new tubes and after about 100 days for the old tubes. However, the fouling resistance values were substantially larger for the old tubes.

  1. The Snellen human calorimeter revisited, re-engineered and upgraded: design and performance characteristics.

    Science.gov (United States)

    Reardon, Francis D; Leppik, Kalle E; Wegmann, René; Webb, Paul; Ducharme, Michel B; Kenny, Glen P

    2006-08-01

    The measurement of whole body heat loss in humans and the performance characteristics of a modified Snellen whole body air calorimeter are described. Modifications included the location of the calorimeter in a pressurized room, control of operating temperature over a range of - 15 to + 35 degrees C, control of ambient relative humidity over a range of 20-65%, incorporation of an air mass flow measuring system to provide real time measurement of air mass flow through the calorimeter, incorporation of a constant load 'eddy current' resistance ergometer and an open circuit, expired gas analysis calorimetry system. The performance of the calorimeter is a function of the sensitivity, precision, accuracy and response time characteristics of the fundamental measurement systems including: air mass flow; thermometry and hygrometry. Calibration experiments included a calibration of the air mass flow sensor, the response of the thermometric measurement system for dry heat loss and the response of the hygrometric measurement system for evaporative heat loss. The air mass flow system was evaluated using standard differential temperature procedures to demonstrate linearity and sensitivity of the device. A novel procedure based on differential hygrometry was developed to ascertain the absolute calibration of air mass flow by resolving the unique system coefficient K. The results of the hygrometric calibration demonstrate the air mass flow response of the system is linear over the range of air mass flows from 6 to 15 kg min(-1). R(2) was 0.995. The average half response time (tR50) was 14.5 +/- 2.1 s. Similarly the results of the thermometric calibration demonstrate that the response of the apparatus is linear over the range of power input measured (coefficient of linearity R(2)=0.9997) with a precision of 0.72 W and an accuracy to within 0.36 W. The average (tR50) over all conditions was 6.0 +/- 1.9 min. In summary, modifications brought to the Snellen calorimeter have

  2. Effects of sorghum wet distillers grains plus solubles in steam-flaked corn-based finishing diets on steer performance, carcass characteristics, and digestibility characteristics

    Science.gov (United States)

    Two studies were conducted to evaluate the effects of sorghum wet distillers grains (SWDGS) in finishing diets on steer performance, carcass characteristics, and nutrient digestibility. In Exp. 1, 240 steers (initial BW = 379 +/-1 kg) were fed steam-flaked corn (SFC)-based diets with or without 25%...

  3. Performance and carcass characteristics of finishing beef cattle managed in a bedded hoop-barn system.

    Science.gov (United States)

    Honeyman, M S; Busby, W D; Lonergan, S M; Johnson, A K; Maxwell, D L; Harmon, J D; Shouse, S C

    2010-08-01

    The use of bedded hoop barns in finishing systems for beef cattle has not been widely researched. In this management system, beef cattle are confined to hoop barns throughout finishing, and bedding is used to absorb animal waste, which results in minimal effluent. The objective of this study was to compare the performance and carcass characteristics of finishing beef steers (n = 1,428) managed in a bedded hoop-barn management system vs. an open-feedlot system with shelter. Six feeding trials were conducted over a 3-yr period. Three trials were conducted during summer-fall and 3 trials were conducted during winter-spring. Crossbred steers were allotted to 3 pens in the hoop-barn system and to 3 pens in the open-lot system (approximately 40 steers per pen in both facility systems). Stocking densities for the steers were 4.65 m(2) per steer in the hoop-barn system and 14.7 m(2) per steer in the open-lot system. The steers were begun on trial weighing 410 and 411 kg (SD = 21), were fed for 102.3 and 103.0 d (SD = 3.8), and were weighed off test at 595 and 602 kg (SD = 21) for the hoop-barn and open-lot systems, respectively. Steer performance measures consisted of ADG, DMI, and G:F. Carcass characteristics were HCW, fat thickness, LM area, KPH percentage, marbling score, USDA yield grade, and USDA quality grade. No year, season, or pen (management system) main effects, or season x management system and year x management system interactions were observed for any of the items measured related to cattle performance or carcass characteristics (P > 0.05). Final mud scores (a subjective evaluation of the amount of soil and manure adhering to the hair coat of the animals) were greater for the steers from the open-lot system compared with those from the hoop-barn system (P < 0.02), suggesting steers in the hoop-barn system carried less mud than steers from the open-lot system. Average daily cornstalk bedding use in the hoop-barn system was 2.3 kg/steer during summer-fall and 2

  4. Questions on optimum utilization of modified bioadsorbents for adsorption of cadmium ions

    OpenAIRE

    MAMEDOVA SEADET OSMAN GIZI

    2015-01-01

    Two modifications of compound additive criteria have been suggested where the first component represents the conditions to reach the maximum quantity of adsorbate in adsorbent, and the second one represents the total expenditure for all adsorption process. It is shown, that the suggested criterion has an extremum property and make it possible to determine the optimum characteristics of adsorption.

  5. Structural Model for the Effects of Environmental Elements on the Psychological Characteristics and Performance of the Employees of Manufacturing Systems

    Directory of Open Access Journals (Sweden)

    Arturo Realyvásquez

    2016-01-01

    Full Text Available This paper analyzes the effects of environmental elements on the psychological characteristics and performance of employees in manufacturing systems using structural equation modeling. Increasing the comprehension of these effects may help optimize manufacturing systems regarding their employees’ psychological characteristics and performance from a macroergonomic perspective. As the method, a new macroergonomic compatibility questionnaire (MCQ was developed and statistically validated, and 158 respondents at four manufacture companies were considered. Noise, lighting and temperature, humidity and air quality (THAQ were used as independent variables and psychological characteristics and employees’ performance as dependent variables. To propose and test the hypothetical causal model of significant relationships among the variables, a data analysis was deployed. Results found that the macroergonomic compatibility of environmental elements presents significant direct effects on employees’ psychological characteristics and either direct or indirect effects on the employees’ performance. THAQ had the highest direct and total effects on psychological characteristics. Regarding the direct and total effects on employees’ performance, the psychological characteristics presented the highest effects, followed by THAQ conditions. These results may help measure and optimize manufacturing systems’ performance by enhancing their macroergonomic compatibility and quality of life at work of the employees.

  6. Structural Model for the Effects of Environmental Elements on the Psychological Characteristics and Performance of the Employees of Manufacturing Systems.

    Science.gov (United States)

    Realyvásquez, Arturo; Maldonado-Macías, Aidé Aracely; García-Alcaraz, Jorge; Cortés-Robles, Guillermo; Blanco-Fernández, Julio

    2016-01-05

    This paper analyzes the effects of environmental elements on the psychological characteristics and performance of employees in manufacturing systems using structural equation modeling. Increasing the comprehension of these effects may help optimize manufacturing systems regarding their employees' psychological characteristics and performance from a macroergonomic perspective. As the method, a new macroergonomic compatibility questionnaire (MCQ) was developed and statistically validated, and 158 respondents at four manufacture companies were considered. Noise, lighting and temperature, humidity and air quality (THAQ) were used as independent variables and psychological characteristics and employees' performance as dependent variables. To propose and test the hypothetical causal model of significant relationships among the variables, a data analysis was deployed. Results found that the macroergonomic compatibility of environmental elements presents significant direct effects on employees' psychological characteristics and either direct or indirect effects on the employees' performance. THAQ had the highest direct and total effects on psychological characteristics. Regarding the direct and total effects on employees' performance, the psychological characteristics presented the highest effects, followed by THAQ conditions. These results may help measure and optimize manufacturing systems' performance by enhancing their macroergonomic compatibility and quality of life at work of the employees.

  7. Comparison of fattening performance, carcass characteristics, and egg quality characteristics of Japanese quails with different feather colors

    OpenAIRE

    Hakan Inci; Bunyamin Sogut; Turgay Sengul; Ahmet Yusuf Sengul; Mehmet Resit Taysi

    2015-01-01

    The objective of this study was to compare fattening performance, carcass traits, and egg quality of Japanese quails with different feather colors (white, dark brown, golden, and wild-type). In the study, 360 one-day-old quail chicks with 4 different feather colors were used as animal material. Quails were fed ad libitum for 42 days to determine fattening performance and carcass traits. To determine egg traits, 48 hens from each group, in a total of 192, were selected and caged according to f...

  8. Investigation of Performance Analysis and Emission Characteristics of Waste Plastic Fuel

    Science.gov (United States)

    Ruban, M.; Ramasubramanian, S.; Pugazhenthi, R.; Sivaganesan

    2017-03-01

    Today the world is confronted with the twin crisis of fossil fuel depletion and stringent emission norms, because of the environmental awareness. The disposal and degradation of waste plastic is a major issue and scarcities of fuel were major focus area of the researchers. In this virtue the waste plastic fuel extraction makes more attention to the researchers. In this research work focused to find the performance of the waste plastic fuel and compared to diesel. The waste plastic fuel extract from thermal cracking method this process the polymer chains were breakdown into useful lower molecular weight compounds and it becomes plastic pyrolysis it can be utilized as a fuel. The properties of the waste plastic fuel is obtained by various testing process and which is analyze and compare with the fossil fuel diesel. It is found that almost it has similar properties to the diesel and almost all properties of the pyrolysis is closer to that of diesel. The characteristics of the pyrolysis were tested in the engine test bed. The pyrolysis / waste plastic fuel can be directly used in diesel engines over the entire load spectrum smoothly without any major modification. The performance of the waste plastic fuel / pyrolysis is evidenced that it is one of the best alternative fuel as well as the waste plastic can be converted into a useful fuel

  9. Influence of guide vane setting in pump mode on performance characteristics of a pump-turbine

    Science.gov (United States)

    Li, Deyou; Wang, Hongjie; Nielsen, Torbjørn K.; Gong, Ruzhi; Wei, Xianzhu; Qin, Daqing

    2016-11-01

    Performance characteristics in pump mode of pump-turbines are vital for the safe and effective operation of pumped storage power plants. They are resultant of Euler head (power input) and hydraulic losses (power dissipation). In this paper, 3-D steady simulations were performed under 13mm, 19mm and 25mm guide vane openings (GVOs). Three groups of operating points under the three GVOs were chosen based on experimental validation to investigate the influence of guide vane setting on flow patterns upstream and downstream. Analysed results show that, the guide vane setting will obviously change the flow pattern downstream, which in turn influences the flow upstream. It shows a strong effect on hydraulic losses in guide and stay vanes. In addition, at the large part load conditions, the change of GVO will increase the relative flow angle at the runner outlet. As a consequence, it decreases the Euler head. However, at other operating conditions, it only has a little influence on Euler head. Flow patterns in pump mode are very dependent on the GVO and discharge.

  10. Comparison of Thermal Performance Characteristics of Ammonia and Propylene Loop Heat Pipes

    Science.gov (United States)

    Kaya, Tarik; Baker, Charles; Ku, Jentung

    2000-01-01

    In this paper, experimental work performed on a breadboard Loop Heat Pipe (LHP) is presented. The test article was built by DCI for the Geoscience Laser Altimeter System (GLAS) instrument on the ICESat spacecraft. The thermal system requirements of GLAS have shown that ammonia cannot be used as the working fluid in this LHP because GLAS radiators could cool to well below the freezing point of ammonia. As a result, propylene was proposed as an alternative LHP working fluid since it has a lower freezing point than ammonia. Both working fluids were tested in the same LHP following a similar test plan in ambient conditions. The thermal performance characteristics of ammonia and propylene LHP's were then compared. In general, the propylene LHP required slightly less startup superheat 5nd less control heater power than the ammonia LHP, The thermal conductance values for the propylene LHP were also lower than the ammonia LHP. Later, the propylene LHP was tested in a thermal vacuum chamber. These tests demonstrated that propylene could meet the GLAS thermal design requirements. Design guidelines were proposed for the next flight-like Development Model (DM) LHP for thermal control of the GLAS instrument.

  11. Characteristic correlation study of UV disinfection performance for ballast water treatment

    Science.gov (United States)

    Ba, Te; Li, Hongying; Osman, Hafiiz; Kang, Chang-Wei

    2016-11-01

    Characteristic correlation between ultraviolet disinfection performance and operating parameters, including ultraviolet transmittance (UVT), lamp power and water flow rate, was studied by numerical and experimental methods. A three-stage model was developed to simulate the fluid flow, UV radiation and the trajectories of microorganisms. Navier-Stokes equation with k-epsilon turbulence was solved to model the fluid flow, while discrete ordinates (DO) radiation model and discrete phase model (DPM) were used to introduce UV radiation and microorganisms trajectories into the model, respectively. The UV dose statistical distribution for the microorganisms was found to move to higher value with the increase of UVT and lamp power, but moves to lower value when the water flow rate increases. Further investigation shows that the fluence rate increases exponentially with UVT but linearly with the lamp power. The average and minimum resident time decreases linearly with the water flow rate while the maximum resident time decrease rapidly in a certain range. The current study can be used as a digital design and performance evaluation tool of the UV reactor for ballast water treatment.

  12. Communication and laboratory performance in parapsychology experiments: demand characteristics and the social organization of interaction.

    Science.gov (United States)

    Wooffitt, Robin

    2007-09-01

    This paper reports findings from a conversation analytic study of experimenter-participant interaction in parapsychology experiments. It shows how properties of communication through which the routine business of the experiment is conducted may have an impact on the research participant's subsequent performance. In this, the study explores social psychological features of the psychology laboratory. In particular, it examines aspects of Orne's (1962) account of what he called the demand characteristics of the psychological experiment. The data come from a corpus of audio recordings of experimenter-participant interaction during experiments on extra-sensory perception. These kinds of experiments, and the phenomena they purport to study, are undoubtedly controversial; however, the paper argues that there are grounds for social psychologists to consider parapsychology experiments as a class (albeit distinctive) of psychology experiments, and, therefore, as sites in which general social psychological and communicative phenomena can be studied. The empirical sections of the paper examine interaction during part of the experimental procedure when the experimenter verbally reviews a record of the participant's imagery reported during an earlier part of the experiment. The analysis shows that the way in which the experimenter acknowledges the research participants' utterances may be significant for the trajectory of the experiment and explores how the participants' subsequent performance in the experiment may be influenced by interactionally generated contingencies.

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

    Science.gov (United States)

    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

  14. Performance Characteristics and Validation of Next-Generation Sequencing for Human Leucocyte Antigen Typing.

    Science.gov (United States)

    Weimer, Eric T; Montgomery, Maureen; Petraroia, Rosanne; Crawford, John; Schmitz, John L

    2016-09-01

    High-resolution human leukocyte antigen (HLA) matching reduces graft-versus-host disease and improves overall patient survival after hematopoietic stem cell transplant. Sanger sequencing has been the gold standard for HLA typing since 1996. However, given the increasing number of new HLA alleles identified and the complexity of the HLA genes, clinical HLA typing by Sanger sequencing requires several rounds of additional testing to provide allele-level resolution. Although next-generation sequencing (NGS) is routinely used in molecular genetics, few clinical HLA laboratories use the technology. The performance characteristics of NGS HLA typing using TruSight HLA were determined using Sanger sequencing as the reference method. In total, 211 samples were analyzed with an overall accuracy of 99.8% (2954/2961) and 46 samples were analyzed for precision with 100% (368/368) reproducibility. Most discordant alleles were because of technical error rather than assay performance. More important, the ambiguity rate was 3.5% (103/2961). Seventy-four percentage of the ambiguities were within the DRB1 and DRB4 loci. HLA typing by NGS saves approximately $6000 per run when compared to Sanger sequencing. Thus, TruSight HLA assay enables high-throughput HLA typing with an accuracy, precision, ambiguity rate, and cost savings that should facilitate adoption of NGS technology in clinical HLA laboratories.

  15. Comparing the Effects of Mesh Size on Benthic Macroinvertebrate Performance Characteristics in Montana streams

    Science.gov (United States)

    Laidlaw, T. L.; Jessup, B.; Stagliano, D.; Stribling, J.; Feldman, D. L.; Bollman, W.

    2005-05-01

    Montana's Department of Environmental Quality (DEQ) has collected macroinvertebrate data for twenty years. During this time, sampling methods and mesh sizes have been modified, though the effects of the modifications on the samples collected have not been studied. DEQ has used and continues to use both 500 and 1200 ìm mesh sizes. The purpose of this study is to evaluate the effects of the different mesh sizes on taxonomic diversity and metric values. Field crews followed DEQ's traveling kick sampling methods and collected samples at each site using both mesh sizes. Sixteen sampling locations were distributed throughout two ecoregions (the Mountains and the Mountain and Valley Foothills) with replicate samples collected at seven locations. We developed a suite of both quantitative and qualitative performance characteristics (precision, accuracy, bias) and directly compared them for each mesh size. Preliminary ordination results showed no significant differences between the community level performance measures. Preliminary metric analysis showed that the 1200 ìm mesh captured a greater abundance and diversity of caddisflies (Trichoptera) than the 500 ìm mesh. This study will determine if data collected using different mesh sizes can be aggregated for development of bioassessment tools and will help DEQ implement consistent statewide sampling protocols.

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

    Directory of Open Access Journals (Sweden)

    Liu Chunbao

    2016-01-01

    Full Text Available 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.

  17. Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Soo-Yong [Department of Mechanical and Aerospace Engineering (ReCAPT), Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Cho, Chong-Hyun [School of Mechanical and Aerospace Engineering, Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Kim, Chaesil [Department of Mechanical Engineering, Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea)

    2008-09-15

    An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

  18. Associations between Otolaryngology Applicant Characteristics and Future Performance in Residency or Practice: A Systematic Review.

    Science.gov (United States)

    Bowe, Sarah N; Laury, Adrienne M; Gray, Stacey T

    2017-06-01

    Objective This systematic review aims to evaluate which applicant characteristics available to an otolaryngology selection committee are associated with future performance in residency or practice. Data Sources PubMed, Scopus, ERIC, Health Business, Psychology and Behavioral Sciences Collection, and SocINDEX. Review Methods Study eligibility was performed by 2 independent investigators in accordance with the PRISMA protocol (Preferred Reporting Items for Systematic Reviews and Meta-analyses). Data obtained from each article included research questions, study design, predictors, outcomes, statistical analysis, and results/findings. Study bias was assessed with the Quality in Prognosis Studies tool. Results The initial search identified 439 abstracts. Six articles fulfilled all inclusion and exclusion criteria. All studies were retrospective cohort studies (level 4). Overall, the studies yielded relatively few criteria that correlated with residency success, with generally conflicting results. Most studies were found to have a high risk of bias. Conclusion Previous resident selection research has lacked a theoretical background, thus predisposing this work to inconsistent results and high risk of bias. The included studies provide historical insight into the predictors and criteria (eg, outcomes) previously deemed pertinent by the otolaryngology field. Additional research is needed, possibly integrating aspects of personnel selection, to engage in an evidence-based approach to identify highly qualified candidates who will succeed as future otolaryngologists.

  19. Effect of nano-scale characteristics of graphene on electrochemical performance of activated carbon supercapacitor electrodes

    Science.gov (United States)

    Jasni, M. R. M.; Deraman, M.; Suleman, M.; Hamdan, E.; Sazali, N. E. S.; Nor, N. S. M.; Shamsudin, S. A.

    2016-02-01

    Graphene with its typical nano-scale characteristic properties has been widely used as an additive in activated carbon electrodes in order to enhance the performance of the electrodes for their use in high performance supercapacitors. Activated carbon monoliths (ACMs) electrodes have been prepared by carbonization and activation of green monoliths (GMs) of pre-carbonized fibers of oil palm empty fruit bunches or self-adhesive carbon grains (SACGs) and SACGs added with 6 wt% of KOH-treated multi-layer graphene. ACMs electrodes have been assembled in symmetrical supercapacitor cells that employed aqueous KOH electrolyte (6 M). The cells have been tested with cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge discharge methods to investigate the effect of graphene addition on the specific capacitance (Csp), specific energy (E), specific power (P), equivalent series resistance (ESR) and response time (τo) of the supercapacitor cells. The results show that the addition of graphene in the GMs change the values of Csp, Emax, Pmax, ESR and τo from (61-96) F/g, 2 Wh/kg, 104 W/kg, 2.6 Ω and 38 s, to the respective values of (110-124) F/g, 3 Wh/kg, 156 W/kg, 3.4 Ω and 63 s. This study demonstrates that the graphene addition in the GMs has a significant effect on the electrochemical behavior of the electrodes.

  20. Performance characteristics of a gelled-electrolyte valve-regulated lead-acid battery

    Indian Academy of Sciences (India)

    S K Martha; B Hariprakash; S A Gaffoor; A K Shukla

    2003-08-01

    12 V/25 AH gelled-electrolyte valve-regulated lead-acid batteries have been assembled in-house and their performance studied in relation to the absorptive glass-microfibre valve-regulated and flooded-electrolyte counterparts at various discharge rates and temperatures between –40°C and 40°C. Although the performance of the gelled-electrolyte valve-regulated battery is similar to both the absorptive glass-microfibre valve-regulated and flooded-electrolyte lead-acid batteries at temperatures above 0°C, it is superior to both the flooded-electrolyte and absorptive glass-microfibre valve-regulated lead-acid batteries at temperatures between 0°C and -40°C. The latter characteristic is attractive for expanding the application regime of valve-regulated lead-acid batteries. The corrosion rate for the positive grids in the gelled-electrolyte is also lower than both the flooded-electrolyte and absorptive glass-microfibre configurations.

  1. Investigation of Various Essential Factors for Optimum Infrared Thermography

    Science.gov (United States)

    OKADA, Keiji; TAKEMURA, Kei; SATO, Shigeru

    2013-01-01

    ABSTRACT We investigated various essential factors for optimum infrared thermography for cattle clinics. The effect of various factors on the detection of surface temperature was investigated in an experimental room with a fixed ambient temperature using a square positioned on a wall. Various factors of animal objects were examined using cattle to determine the relationships among presence of hair, body surface temperature, surface temperature of the eyeball, the highest temperature of the eye circle, rectum temperature and ambient temperature. Also, the surface temperature of the flank at different time points after eating was examined. The best conditions of thermography for cattle clinics were determined and were as follows: (1) The distance between a thermal camera and an object should be fixed, and the camera should be set within a 45-degree angle with respect to the objects using the optimum focal length. (2) Factors that affect the camera temperature, such as extreme cold or heat, direct sunshine, high humidity and wind, should be avoided. (3) For the comparison of thermographs, imaging should be performed under identical conditions. If this is not achievable, hairless parts should be used. PMID:23759714

  2. Optimum Tower Crane Selection and Supporting Design Management

    Directory of Open Access Journals (Sweden)

    Hyo Won Sohn

    2014-08-01

    Full Text Available To optimize tower crane selection and supporting design, lifting requirements (as well as stability should be examined, followed by a review of economic feasibility. However, construction engineers establish plans based on data provided by equipment suppliers since there are no tools with which to thoroughly examine a support design’s suitability for various crane types, and such plans lack the necessary supporting data. In such cases it is impossible to optimize a tower crane selection to satisfy lifting requirements in terms of cost, and to perform lateral support and foundation design. Thus, this study is intended to develop an optimum tower crane selection and supporting design management method based on stability. All cases that are capable of generating an optimization of approximately 3,000 ~ 15,000 times are calculated to identify the candidate cranes with minimized cost, which are examined. The optimization method developed in the study is expected to support engineers in determining the optimum lifting equipment management.

  3. Biological chip technology to quickly batch select optimum cryopreservation procedure

    Institute of Scientific and Technical Information of China (English)

    YU Lina; LIU Jing; ZHOU Yixin; HUA Zezhao

    2007-01-01

    In the practices of cryobiology,selection of an optimum freeze/thawing program and an idealistic cryoprotective agent often requires rather tedious,time consuming and repetitive tests.Integrating the functions of sample preparation and viability detection,the concept of biochip technology was introduced to the field of cryopreservation,aiming at quickly finding an optimum freezing and thawing program.Prototype devices were fabricated and corresponding experimental tests were performed.It was shown that microflow-channel chip could not offer a high quality solution distribution.As an alternative,the spot-dropping chip proved to be an excellent way to load the sample quickly and reliably.Infrared thermal mapping on such a chip showed that it had a rather uniform heat transfer boundary.Applying the spot-dropping chip combined with the thermoelectric cooling device,the final output of cryopreservation of multiple samples was tested,and the optimal freeze/thawing program as well as the potentially best concentration of the cryoprotective agent was found by analyzing the results.Further,application of this technique to measure the thermo-physical properties of the cryo-protective agent was also investigated.The study demonstrated that a biochip with integrated automatic loading and inspection units opens the possibility of a massive optimization of the complex cryopreservation program in a quicker and more economical way.

  4. Optimum Tower Crane Selection and Supporting Design Management

    Directory of Open Access Journals (Sweden)

    Hyo Won Sohn

    2014-08-01

    Full Text Available To optimize tower crane selection and supporting design, lifting requirements (as well as stability should be examined, followed by a review of economic feasibility. However, construction engineers establish plans based on data provided by equipment suppliers since there are no tools with which to thoroughly examine a support design's suitability for various crane types, and such plans lack the necessary supporting data. In such cases it is impossible to optimize a tower crane selection to satisfy lifting requirements in terms of cost, and to perform lateral support and foundation design. Thus, this study is intended to develop an optimum tower crane selection and supporting design management method based on stability. All cases that are capable of generating an optimization of approximately 3,000 ˜ 15,000 times are calculated to identify the candidate cranes with minimized cost, which are examined. The optimization method developed in the study is expected to support engineers in determining the optimum lifting equipment management.

  5. Developments of optimum flip-chip bonding process

    Science.gov (United States)

    Jang, Dong H.; Kang, Sa Y.; Lee, Y. M.; Oh, S. Y.

    1997-08-01

    Flip-chip soldering is the critical technology for solving the current issues of electronic packaging industries that require the high I/O's. In order to increase the manufacturing ability of flip-chip technology, however, yield and reliability tissues should overcome. In this study, optimum flip-chip bonding process has been developed by using the test chips that had the electroplated solder bumps. Test chips are composed of three different types that are i) peripheral array pad chip, ii) peripheral array pad chip, and iii) area array pad chip. Each test chip has the daisy chain to consider the effect of reliability test. The electrical resistance was measured before and after reliability test. Based on these measurement, failure mode resulted from the moisture absorption was studied using scanning acoustic microscope. To achieve an optimum reflow profile of solder bump, correct temperature profile was set up with respect to the resin base flux. Different bonding forces were tested. Four underfill encapsulants were evaluated for minimum voids that caused the severe defects after reliability test. Also, the gap heights were measured with respect to applied bonding force after underfill was performed. Results from the moisture absorption and thermal cycling were discussed for flip-chip bonding on BT-resin substrates. The test vehicles using flip-chip technology have passed moisture preconditioning and temperature cycling tests.

  6. Optimum Transmitter Power Control in WCDMA Cellular Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Power control is an important technique in WCDMA mobile systems for both increasing system capacity and guaranteeing the required QoS (time delay and wireless link transmission quality) of multimedia services. The optimum power control for narrow band CDMA cellular systems is a problem of single threshold optimization. Because these systems have only one type of traffic and have the same QoS requirement. However, WCDMA mobile systems should provide multimedia services and different types of traffic have different QoS requirements. Thus, the power control in WCDMA mobile systems doesn't be a problem of single threshold optimizing, but turns into the optimizing problem of multi-thresholds. In this paper, we analyze the power control problem in WCDMA cellular mobile systems and propose the optimum transmitter power control algorithm. Three criteria to optimize transmitter power levels of multi-thresholds based on grading the priority orders of multimedia services are proposed. Simulation results show that the proposed algorithms are more effective than conventional algorithms and can provide better performance for WCDMA cellular mobile systems.

  7. Anthropometric Characteristics and Performance Capabilities of Highly Trained Motocross Athletes Compared With Physically Active Men.

    Science.gov (United States)

    Bach, Christopher W; Brown, Ann F; Kinsey, Amber W; Ormsbee, Michael J

    2015-12-01

    Motocross (MX) is a physically demanding sport with little research concerning the physiological characteristics of these athletes. The purpose of this study was to assess the anthropometric characteristics and performance capabilities of highly trained MX athletes (n = 20; 19 ± 1.6 years) compared with age-matched physically active (PA) men (n = 22; 22 ± 2.9 years). Testing was performed on 2 occasions. The initial visit consisted of a personality assessment in addition to the following (in order): anthropometrics, body composition, anaerobic power/fatigue, isokinetic/isometric strength and fatigue, and flexibility. The second visit consisted of peak oxygen uptake (V[Combining Dot Above]O2peak), handgrip strength, maximum push-ups in 1 minute, extended arm hang time to exhaustion (TTE), and 90° weighted wall-sit tests. All anthropometric and performance data were analyzed using independent samples t-tests to compare group means. Significance was set at p ≤ 0.05. Data are reported as mean ± SD. There were no significant differences between groups in anthropometric or body composition measurements except android fat (MX: 11.7 ± 1.9% vs. PA: 16.4 ± 8.4%, p = 0.04) and biceps circumference (MX: 30.1 ± 2.0 vs. PA: 33.1 ± 3.2 cm, p = 0.001). MX had significantly higher absolute and relative mean anaerobic power (747.3 ± 63.7 vs. 679.7 ± 93.5 W, p = 0.009 and 10.0 ± 0.6 vs. 9.2 ± 1.3 W·kg, p = 0.002, respectively), relative anaerobic peak power (12.7 ± 0.8 vs. 11.9 ± 1.4 W·kg, p = 0.029), TTE (550.1 ± 70.6 vs. 470.1 ± 93.2 seconds, p = 0.004), and extended arm hang duration (113.3 ± 44.9 vs. 73.4 ± 25.3 seconds, p = 0.001). These results suggest highly trained MX athletes possess certain physiological adaptations that likely result from sport-specific demands compared with PA.

  8. Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers

    Science.gov (United States)

    Deters, Robert W.

    The low Reynolds number effects of small-scale propellers were investigated. At the Reynolds numbers of interest (below 100,000), a decrease in lift and an increase in drag is common making it difficult to predict propeller performance characteristics. A propeller testing apparatus was built to test small scale propellers in static conditions and in an advancing flow. Twenty-seven off-the-shelf propellers, with diameters ranging from 2.25 in to 9 in, were tested in order to determine the general effects of low Reynolds numbers on small propellers. From these tests, increasing the Reynolds number for a propeller increases its efficiency by either increasing the thrust produced or decreasing the power. By doubling the Reynolds number of a propeller, it is not uncommon to increase the efficiency by more the 10%. Using off-the-shelf propellers limits the geometry available and finding propellers of the same geometry but of different scale is very difficult. To solve this problem, four propellers were design and built using a 3D printer. Two of the propellers were simple rectangular twisted blades of different chords. Another propeller was modeled after a full-scale propeller. The fourth propeller was created using inverse design to minimize power loss. Each propeller was built in a 5-in and 9-in diameter version in order to test a larger range of Reynolds numbers. A separate propeller blade and hub system was created to allow each propeller to be tested with different pitch angles and to test each propeller in a 2-, 3-, and 4-blade version. From the performance results of the 3D printed propellers, it was shown that propellers of different scale, but tested at the same Reynolds number, had about the same performance results. Finally, the slipstreams of different propellers were measured using a 7-hole probe. Propeller slipstreams can have a large effect on the aerodynamics of lifting surfaces downstream of the propeller. Small UAVs and MAVs flying in close proximity

  9. Optimum Design of Structure Shape for Offshore Jacket Platforms

    Institute of Scientific and Technical Information of China (English)

    FENG Sheng; SONG Yupu; ZHANG Rixiang

    2000-01-01

    With the introduction of the design variables of nodal coordinates, which reflect the embedded depth of the pile and the jacket bed height, a shape optimum design model for offshore jacket platforms is established. A sequential two-level optimum algorithm is developed based on the design variable gradation. On the basis of the finite element method, the sensitivity of the objective function and nodal displacement is analyzed. As an example, the BZ281 oil storage offshore platform, which lies in the Bohai oil field, is designed with the shape optimum model The results are compared with the cross-section optimum design. The tendency of design variables and its reasons in the two methods are analyzed. In the shape optimum design, the value of objective function is obviously smaller than that of the initial design and the cross-section optimum design. Therefore, the advantage of structure shape optimum design for jacket platforms is remarkable.

  10. Analysis of Performance of Jet Engine from Characteristics of Components II : Interaction of Components as Determined from Engine Operation

    Science.gov (United States)

    Goldstein, Arthur W; Alpert, Sumner; Beede, William; Kovach, Karl

    1949-01-01

    In order to understand the operation and the interaction of jet-engine components during engine operation and to determine how component characteristics may be used to compute engine performance, a method to analyze and to estimate performance of such engines was devised and applied to the study of the characteristics of a research turbojet engine built for this investigation. An attempt was made to correlate turbine performance obtained from engine experiments with that obtained by the simpler procedure of separately calibrating the turbine with cold air as a driving fluid in order to investigate the applicability of component calibration. The system of analysis was also applied to prediction of the engine and component performance with assumed modifications of the burner and bearing characteristics, to prediction of component and engine operation during engine acceleration, and to estimates of the performance of the engine and the components when the exhaust gas was used to drive a power turbine.

  11. Interactions Between Channel Topography and Hydrokinetic Turbines: Sediment Transport, Turbine Performance, and Wake Characteristics

    Science.gov (United States)

    Hill, Craig Steven

    Accelerating marine hydrokinetic (MHK) renewable energy development towards commercial viability requires investigating interactions between the engineered environment and its surrounding physical and biological environments. Complex and energetic hydrodynamic and morphodynamic environments desired for such energy conversion installations present difficulties for designing efficient yet robust sustainable devices, while permitting agency uncertainties regarding MHK device environmental interactions result in lengthy and costly processes prior to installing and demonstrating emerging technologies. A research program at St. Anthony Falls Laboratory (SAFL), University of Minnesota, utilized multi-scale physical experiments to study the interactions between axial-flow hydrokinetic turbines, turbulent open channel flow, sediment transport, turbulent turbine wakes, and complex hydro-morphodynamic processes in channels. Model axial-flow current-driven three-bladed turbines (rotor diameters, dT = 0.15m and 0.5m) were installed in open channel flumes with both erodible and non-erodible substrates. Device-induced local scour was monitored over several hydraulic conditions and material sizes. Synchronous velocity, bed elevation and turbine performance measurements provide an indication into the effect channel topography has on device performance. Complimentary experiments were performed in a realistic meandering outdoor research channel with active sediment transport to investigate device interactions with bedform migration and secondary turbulent flow patterns in asymmetric channel environments. The suite of experiments undertaken during this research program at SAFL in multiple channels with stationary and mobile substrates under a variety of turbine configurations provides an in-depth investigation into how axial-flow hydrokinetic devices respond to turbulent channel flow and topographic complexity, and how they impact local and far-field sediment transport characteristics

  12. Improvement of mechanical characteristics and performances with Ni diffusion mechanism throughout Bi-2223 superconducting matrix

    Science.gov (United States)

    Sarıtekin, N. K.; Bilge, H.; Kahraman, M. F.; Zalaoǧlu, Y.; Pakdil, M.; Doǧruer, M.; Yıldırım, G.; Oz, M.

    2016-03-01

    This study is interested in the role of diffusion annealing temperature (650-850°C) on the mechanical characteristics and performance of pure and Ni diffused Bi-2223 superconducting materials by means of standard compression tests and Vickers hardness measurements at performed different applied loads in the range of 0.245-2.940N and theoretical calculations. Based on the experimental findings, the mechanical performances improve with increasing annealing temperature up to 700 °C beyond which they degrade drastically due to the increased artificial disorders, cracks and irregular grain orientation distribution. In other words, the penetration of excess Ni inclusions accelerates both the dislocation movement and especially the cracks and voids propagation as a result of the decrement in the Griffith critical crack length. Further, it is to be mentioned here that all the sample exhibit typical indentation size effect (ISE) behavior. In this respect, both the plastic (irreversible) and elastic (reversible) deformations have dominant role on the superconducting structures as a result of the enhancement in the elastic recovery. At the same time elastic modulus, yield strength and fracture toughness parameters are theoretically extracted from the microhardness values. Moreover, the elastic modulus parameters are compared with the experimental values. It is found that the differentiation between the comparison results enhances hastily with the increment in the applied indentation test loads due to the existence of the increased permanent disorders, lattice defects and strains in the stacked layers. Namely, the error level increases away from the actual crystal structure. Additionally, the microhardness values are theoretically analyzed for the change of the mechanical behaviors with the aid of Meyer's law, elastic/plastic deformation and Hays-Kendall approaches for the first time.

  13. Prediction of circulation control performance characteristics for Super STOL and STOL applications

    Science.gov (United States)

    Naqvi, Messam Abbas

    due to the lack of a simple prediction capability. This research effort was focused on the creation of a rapid prediction capability of Circulation Control Aerodynamic Characteristics which could help designers with rapid performance estimates for design space exploration. A morphological matrix was created with the available set of options which could be chosen to create this prediction capability starting with purely analytical physics based modeling to high fidelity CFD codes. Based on the available constraints, and desired accuracy meta-models have been created around the two dimensional circulation control performance results computed using Navier Stokes Equations (Computational Fluid Dynamics). DSS2, a two dimensional RANS code written by Professor Lakshmi Sankar was utilized for circulation control airfoil characteristics. The CFD code was first applied to the NCCR 1510-7607N airfoil to validate the model with available experimental results. It was then applied to compute the results of a fractional factorial design of experiments array. Metamodels were formulated using the neural networks to the results obtained from the Design of Experiments. Additional validation runs were performed to validate the model predictions. Metamodels are not only capable of rapid performance prediction, but also help generate the relation trends of response matrices with control variables and capture the complex interactions between control variables. Quantitative as well as qualitative assessments of results were performed by computation of aerodynamic forces & moments and flow field visualizations. Wing characteristics in three dimensions were obtained by integration over the whole wing using Prandtl's Wing Theory. The baseline Super STOL configuration [3] was then analyzed with the application of circulation control technology. The desired values of lift and drag to achieve the target values of Takeoff & Landing performance were compared with the optimal configurations obtained

  14. Dynamic characteristics and performance evaluation for the part strut failure of the vibration isolation platform on satellites

    Science.gov (United States)

    Zhang, Yao; Sheng, Chao; Guo, Zixi; Wang, Youyi; Li, Wenbo

    2017-04-01

    The dynamic characteristics and performance evaluation for the part strut failure of the vibration isolation platform are presented in this paper. The first step provides and mathematically describes two types of strut failure: fractured and stuck. Secondly, the dynamic model of the vibration isolation platform, which considers the part strut failure, is established using the Newton-Euler method and a constraint equation to evaluate its dynamic characteristics and performance. Then, with reasonable assumptions, the dynamic model of the satellite, which has a vibration isolation platform and vibration sources (such as control moment gyros) of three working situations (without and with two types of strut failure), is simplified to analyse the frequency domain characteristic and coupling characteristic with the attitude control system. Finally, a numerical simulation is used to study the effect of the vibration isolation platform with part strut failure on the attitude control and stabilization, and the attitude control performance is evaluated.

  15. Impacts of teachers’ competency on job performance in research universities with industry characteristics: Taking academic atmosphere as moderator

    Directory of Open Access Journals (Sweden)

    Anguo Xu

    2014-10-01

    Full Text Available Purpose: Research universities with industry characteristics play an irreplaceable role in national economic development and social development. With the rapid development of research universities with industry characteristics in China, these universities face new challenges in managing teachers and promoting their quality. This paper aims to examine the impact of teachers’ competency on job performance in research university with industry characteristics Design/methodology/approach: Based on the behavioral event interview and questionnaire methods, a four-dimension (i.e. basic quality, teaching ability, industry awareness and research capacity competency model was proposed, the influence mechanism of competency on job performance was examined using empirical research. Findings: We found that there is a significant positive correlation between the teachers’ competency level, four dimensions and job performance in research universities with industry characteristics, especially between research capacity, teaching ability, industry awareness and job performance. And academic atmosphere plays a regulatory role in the interaction between the competency and job performance. Practical implications: Our findings can help to improve the management level of teachers in research universities with industry characteristics.Originality/value: The paper introduces the competency theory to the teacher management in research universities with industry characteristics, and gives some interesting findings.

  16. Clinical performance and wear characteristics of veneered lithia-disilicate-based ceramic crowns.

    Science.gov (United States)

    Suputtamongkol, Kallaya; Anusavice, Kenneth J; Suchatlampong, Chatcharee; Sithiamnuai, Phira; Tulapornchai, Chantana

    2008-05-01

    The objectives of this study were to characterize the clinical performance and wear characteristics of lithia-disilicate-based ceramic crowns. Thirty posterior crowns were made using the heat-pressing technique and lithia-disilicate-based core ceramic. Subjects were recalled annually. The quality of crowns and adjacent gingival tissues were examined using nine criteria for acceptability. All crowns were examined and ranked from 4 (Excellent) to 1 (Unacceptable) for each criterion. Impressions were made for replica models at each appointment. Wear characteristics of dental ceramic and enamel were obtained by comparing the surface of the original model with the follow-up model using a laser scanner. Twenty-nine subjects returned for the 1-year recall examination. The maximum clenching force for the 30 subjects ranged from 125 to 815 N. All clinical criteria were ranked good to excellent at the 1-year recall exam and no fractures were observed. The mean occlusal wear volumes for the ceramic crowns after 1 year were 0.19 (0.065)mm3 for premolar sites and 0.34 (0.08)mm3 for molar sites. The mean occlusal wear volumes of opposing enamel after 1 year were 0.21 (0.06)mm3 for premolar teeth and 0.50 (0.22)mm3 for molar teeth. The mean occlusal wear volume of ceramic molar crowns was significantly lower than the volume of enamel wear of the opposing teeth (p

  17. Optimum harvest maturity for Leymus chinensis seed

    Directory of Open Access Journals (Sweden)

    Jixiang Lin

    2016-06-01

    Full Text Available Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT and accelerated ageing test (AAT. Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest.

  18. Optimum Energy Window In Liver Scintigraphy

    Directory of Open Access Journals (Sweden)

    Alireza Sadremomtaz

    2015-07-01

    Full Text Available Abstract In liver scintigraphy radioactive tracers in addition to liver are accumulated in other organs such as spleen. It leads to the presence of secondary source which affects image quality. Therefore knowing the influence of the noise arising from the secondary source and trying to reduce the additional data is necessary. In nuclear medicine imaging using of energy window is a useful way to reduce the noise. In this paper we try to find an optimum energy window to reduce the noise for two different low energy collimators. Liver scintigraphy images with and without activity in spleen were simulated by SIMIND software with different energy window percentages and with Low-Energy High-Resolution LEHR and Low-Energy General-Purpose LEGP collimators. We used with activity of 190 MBq. Spleen was outside of the camera field of view so that just its noise effects on the liver image is examined. Finally the images of liver with activity in spleen were compared with that without activity in spleen by MATLAB code.

  19. Optimum size of nanorods for heating application

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, G., E-mail: seshg@stanford.edu; Thaokar, Rochish; Mehra, Anurag

    2014-08-01

    Magnetic nanoparticles (MNP's) have become increasingly important in heating applications such as hyperthermia treatment of cancer due to their ability to release heat when a remote external alternating magnetic field is applied. It has been shown that the heating capability of such particles varies significantly with the size of particles used. In this paper, we theoretically evaluate the heating capability of rod-shaped MNP's and identify conditions under which these particles display highest efficiency. For optimally sized monodisperse particles, the power generated by rod-shaped particles is found to be equal to that generated by spherical particles. However, for particles which are not mono dispersed, rod-shaped particles are found to be more effective in heating as a result of the greater spread in the power density distribution curve. Additionally, for rod-shaped particles, a dispersion in the radius of the particle contributes more to the reduction in loss power when compared to a dispersion in the length. We further identify the optimum size, i.e the radius and length of nanorods, given a bi-variate log-normal distribution of particle size in two dimensions. - Highlights: • Theoretically estimated loss power of magnetic nanorods. • Compared the heat generation by nanorods and nano-spheres. • Incorporated size distribution of particles into calculations. • Nanorods are more efficient than nano-spheres for heating. • 2D heat maps for optimizing size of nanorods for heating.

  20. Optimum Currency Area Criteria in the Greece

    Directory of Open Access Journals (Sweden)

    Milovan Rankov

    2013-08-01

    Full Text Available Creation of a monetary union in any region, regardless of the structure and level of development among countries, carries along certain costs and benefits. This paper explains Mundell’s concept of Optimum Currency Area and criteria that are needed to achieve it. Viewed through the prism of these criteria the EMU is currently far from achieving the OCA confirming the current crisis in Greece and other PIIGS countries. The example of Greece and shortcomings that contributed to its current crisis represents the biggest cost and a break-even point for the future of the monetary union. However, it is encouraging that Greece is not alone in its problems, since various funds for help have been established in a relatively short period of time. The reason for this is certainly a huge cost if any country should leave the union and the spillover effect that it would cause. Certainly serious transformations can be expected and the result should be a stronger union with better control from supra-national level.

  1. Optimum harvest maturity for Leymus chinensis seed

    Science.gov (United States)

    Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui

    2016-01-01

    ABSTRACT Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257

  2. An Optimum Solution for Electric Power Theft

    Directory of Open Access Journals (Sweden)

    Aamir Hussain Memon

    2013-07-01

    Full Text Available Electric power theft is a problem that continues to plague power sector across the whole country. Every year, the electricity companies face the line losses at an average 20-30% and according to power ministry estimation WAPDA companies lose more than Rs. 125 billion. Significantly, it is enough to destroy the entire power sector of country. According to sources 20% losses means the masses would have to pay extra 20% in terms of electricity tariffs. In other words, the innocent consumers pay the bills of those who steal electricity. For all that, no any permanent solution for this major issue has ever been proposed. We propose an applicable and optimum solution for this impassable problem. In our research, we propose an Electric power theft solution based on three stages; Transmission stage, Distribution stage, and User stage. Without synchronization among all, the complete solution can not be achieved. The proposed solution is simulated on NI (National Instruments Circuit Design Suite Multisim v.10.0. Our research work is an implicit and a workable approach towards the Electric power theft, as for conditions in Pakistan, which is bearing the brunt of power crises already

  3. Corrosion and optimum corrosion protection potential offriction stir welded 5083-O Al alloy for leisure ship

    Institute of Scientific and Technical Information of China (English)

    Sung-Hyeon PARK; Jong-Shin KIM; Min-Su HAN; Seong-Jong KIM

    2009-01-01

    Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al alloy. Polarization trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is -1.6 V, corresponding to the crossover point between concentration polarization and activation polarization. However, the optimum protection potential is between -1.5 and -0.7 V since the current density at these values is low in the potentiostatic tests. When a galvanic cell is formed in the seawater, the welds exhibit electrochemically stable trends. Welded parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

  4. Performance characteristics of a new automated method for measurement of anti-cyclic citrullinated peptide.

    Science.gov (United States)

    Noordegraaf, Madelon; Wolthuis, Albert; Peters, Frans; de Groot, Monique; Hoedemakers, Rein

    2015-06-01

    Rheumatoid arthritis (RA) is a chronic inflammatory auto-immune disease affecting approximately 1%-2% of the population worldwide. RA is a potentially crippling disease since it results in malformation of the joints. RA is mostly diagnosed based on clinical manifestations but serological tests against autoantibodies, such as rheumatoid factor and anti-cyclic citrullinated peptides (aCCP), are available. The presence of aCCP antibodies is strongly associated with a more severe, destructive disease course. Recently, a new test for the measurement of aCCP antibodies on the IMMULITE 2000(XPi) platform was developed by Siemens Healthcare. In this study we investigated the performance characteristics of this new aCCP test in four different hospital laboratories and compared the new test with three different commercially available platforms. Samples were collected from patients presented to the hospital for aCCP measurement. Serum aCCP levels were determined by aCCP (Ig)G assay for IMMULITE 2000(XPi) systems (Siemens Healthcare), ImmunoScan RA enzyme-linked immunosorbent assay (ELISA) test (Eurodiagnostica), Immunocap 250 (Thermofisher) or aCCP IgG assay on the Modular system (Roche Diagnostics). The evaluation protocol consisted of within-run imprecision (20 sequential runs), between-run imprecision (16 workdays), comparison of serum and plasma measurement and method comparison. The within-run imprecision (n=20) for aCCP IgG assay on three different IMMULITE 2000(XPi) systems ranged from 3.0% to 6.9% at levels 3.2-171.2 U/mL. Between-run imprecision (n=16 days) ranged from 5.2% to 11% at levels of 3.2-106.9 U/mL. Method comparison showed good correlation when samples were measured on two different Immulite analyzers in two different hospital laboratories [0.21+0.96x (n=40)]. Method comparison of the IMMULITE 2000(XPi) aCCP test with aCCP on Immunoscan RA ELISA (n=112), Immunocap 250 (n=105) and the Modular system (n=289) resulted in a concordance of 90.2%, 93.3% and 94

  5. Characteristics and performance of the first commercial multileaf collimator for a robotic radiosurgery system

    Energy Technology Data Exchange (ETDEWEB)

    Fürweger, Christoph, E-mail: christoph.fuerweger@cyber-knife.net [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam 3075 EA, The Netherlands and European CyberKnife Center Munich, Munich 81377 (Germany); Prins, Paulette; Coskan, Harun; Heijmen, Ben J. M. [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam 3075 EA (Netherlands)

    2016-05-15

    Purpose: The “InCise™ multileaf-collimator (MLC)” is the first commercial MLC to be mounted on a robotic SRS/SBRT platform (CyberKnife). The authors assessed characteristics and performance of this novel device in a preclinical five months test period. Methods: Commissioning beam data were acquired with unshielded diodes. EBT3 radiochromic films were employed for measurement of transmission, leaf/bank position accuracy (garden fence) before and after exercising the MLC, for end-to-end testing and further characterization of the beam. The robot workspace with MLC was assessed analytically by transformation to an Euler geometry (“plane,” “gantry,” and “collimator” angles) and by measuring pointing accuracy at each node. Stability over time was evaluated in picket fence and adapted Winston–Lutz tests (AQA). Results: Beam penumbrae (80%–20%, with 100% = 2 × dose at inflection point for field sizes ≥ 50 × 50 mm{sup 2}) were 2.2–3.7 mm for square fields in reference condition (source-axis-distance 800 mm, depth 15 mm) and depended on field size and off-axis position. Transmission and leakage did not exceed 0.5%. Accessible clinical workspace with MLC covered non-coplanar gantry angles of [−113°; +112°] and collimator angles of [−100°; +107°], with an average robot pointing accuracy of 0.12 ± 0.09 mm. For vertical beams, garden fence tests exhibited an average leaf positioning error of ≤0.2 mm, which increased by 0.25 and 0.30 mm (banks X1 and X2) with leaves traveling parallel to gravity. After execution of a leaf motion stress routine, garden fence tests showed slightly increased jaggedness and allowed to identify one malfunctioning leaf motor. Total system accuracy with MLC was 0.38 ± 0.05 mm in nine end-to-end tests. Picket fence and AQA tests displayed stable results over the test period. Conclusions: The InCise™ MLC for CyberKnife showed high accuracy and adequate characteristics for SRS/SBRT applications. MLC performance

  6. Performance characteristics of the MAMMOCARE PET system based on NEMA standard

    Science.gov (United States)

    Moliner, L.; Correcher, C.; Hellingman, D.; Alamo, J.; Carrilero, V.; Orero, A.; González, A. J.; Benlloch, J. M.

    2017-01-01

    In this work, we present the performance characteristics of the MAMMOCARE PET prototype based on an adaptation of the NU 4-2008 NEMA standard. MAMMOCARE is a project under the European Commission's 7th Framework programme to develop a breast biopsy system guided by a dedicated breast PET (dbPET) images. The PET system is formed by two rings with twelve detector modules each. The transaxial FOV is 170 mm and the axial FOV is 94 mm. The system can separate the detectors up to 60 mm in transaxial plane to allow the biopsy needle entrance. The acquisitions are reconstructed using the LMOS algorithm with tube-of-response (TOR) backprojector, 1 iteration and 16 subsets. The voxel and pixel sizes are (1 × 1 × 1) mm3 and (1.6 × 1.6) mm2 respectively. The radial resolution measured is 1.62 mm in the center of the FOV and 3.45 mm at 50 mm off the center in the radial direction using the closed configuration. In the open configuration the resolution reaches 1.85 mm and 3.65 mm at center and at 50 mm off-center. The adapted recovery coefficients (ARC) are measured for six hot rods inside a cylindrical phantom with a warm background. The ratio between hot and background regions is 10. The ARC values for the closed configuration are 0.32, 0.77 and 0.96 for the inserts with a diameter of 4.5 mm, 8.3 mm and 25 mm, respectively. These values decrease to 0.16, 0.52 and 0.77 for the open configuration. The sensitivity measured using an energy window of 250 keV-750 keV is 3.6% and 2.5% for the closed and open configurations respectively. The NEC peak is 141 kcps@68 MBq and 147 kcps@78 MBq for closed and open configurations. The performance characteristics measured with the open ring configuration decreases with respect the closed configuration, however the values remain comparable to other dbPETs.

  7. Optimum coil insertion speed of various coils in brain aneurysm embolization in vitro.

    Science.gov (United States)

    Konishi, Yoshifumi; Takeuchi, Masataka; Fukasaku, Kazuaki

    2016-10-01

    A coil must comprise material with shape memory to perform optimal coil embolization. To achieve this, the alloy characteristics of the coil (hardness, shape, and thickness) must be understood. In this experiment, a catheter was fixed in the bright position and the movement of the coil was observed under a constant rate of insertion; the optimal insertion rate during clinical use was investigated. The first coil insertion speed was evaluated using simulated aneurysms in an in vivo arterial model. The results showed that the insertion force relates to the deployment shape of the coil, that the feedback through the force indicator using sound is very effective, and that the recorder is useful for analysis of coil embolization. The inserted coils during aneurysm embolization were able to wind uniformly within the aneurysm due to a variety of factors (guiding or micro-catheter position and kick-back phenomenon such as delivery wire). Optimal speed is achieved with proper coil design, which allows the coil to be inserted into the aneurysm. The shape and size of the aneurysm can help determine the necessary size and design of the coil that should be used during the optimal speed range. Aneurysm wall and coil characteristics are considered, along with the friction state of the coil (hardness, shape, and thickness), leading to improvements in safety during the insertion procedure at optimum speed.

  8. Optimum Power and Rate Allocation for Coded V-BLAST: Average Optimization

    CERN Document Server

    Kostina, Victoria

    2010-01-01

    An analytical framework for performance analysis and optimization of coded V-BLAST is developed. Average power and/or rate allocations to minimize the outage probability as well as their robustness and dual problems are investigated. Compact, closed-form expressions for the optimum allocations and corresponding system performance are given. The uniform power allocation is shown to be near optimum in the low outage regime in combination with the optimum rate allocation. The average rate allocation provides the largest performance improvement (extra diversity gain), and the average power allocation offers a modest SNR gain limited by the number of transmit antennas but does not increase the diversity gain. The dual problems are shown to have the same solutions as the primal ones. All these allocation strategies are shown to be robust. The reported results also apply to coded multiuser detection and channel equalization systems relying on successive interference cancelation.

  9. Developing an Optimum Protocol for Thermoluminescence Dosimetry with GR-200 Chips using Taguchi Method.

    Science.gov (United States)

    Sadeghi, Maryam; Faghihi, Reza; Sina, Sedigheh

    2016-11-24

    Thermoluminescence dosimetry (TLD) is a powerful technique with wide applications in personal, environmental and clinical dosimetry. The optimum annealing, storage and reading protocols are very effective in accuracy of TLD response. The purpose of this study is to obtain an optimum protocol for GR-200; LiF: Mg, Cu, P, by optimizing the effective parameters, to increase the reliability of the TLD response using Taguchi method. Taguchi method has been used in this study for optimization of annealing, storage and reading protocols of the TLDs. A number of 108 GR-200 chips were divided into 27 groups, each containing four chips. The TLDs were exposed to three different doses, and stored, annealed and read out by different procedures as suggested by Taguchi Method. By comparing the signal-to-noise ratios the optimum dosimetry procedure was obtained. According to the results, the optimum values for annealing temperature (°C), Annealing Time (s), Annealing to Exposure time (d), Exposure to Readout time (d), Pre-heat Temperature (°C), Pre-heat Time (s), Heating Rate (°C/s), Maximum Temperature of Readout (°C), readout time (s) and Storage Temperature (°C) are 240, 90, 1, 2, 50, 0, 15, 240, 13 and -20, respectively. Using the optimum protocol, an efficient glow curve with low residual signals can be achieved. Using optimum protocol obtained by Taguchi method, the dosimetry can be effectively performed with great accuracy.

  10. Some Optimum and Suboptimum Frame Synchronizers for Binary Data in Gaussian Noise

    DEFF Research Database (Denmark)

    Nielsen, Palle Tolstrup

    1973-01-01

    In this correspondence we investigate the performance of several optimum and suboptimum devices for locating a sync word in data corrupted by Gaussian noise. One suboptimum synchronizer, which is extremely simple to instrument, is shown to perform virtually optimally over the entire range...

  11. Three propositions on why characteristics of performance management systems converge across policy areas with different levels of task complexity

    DEFF Research Database (Denmark)

    Bjørnholt, Bente; Lindholst, Andrej Christian; Agger Nielsen, Jeppe

    2014-01-01

    This article investigates the differences and similarities between performance management systems across public services. We offer three propositions as to why the characteristics of performance management systems may still converge across policy areas in the public sector with different levels...... of task complexity amidst a lack of formal and overarching, government-wide policies. We advance our propositions from a case study comparing the characteristics of performance management systems across social services (eldercare) and technical services (park services) in Denmark. Contrary to expectations...... for divergence due to differences in task complexity, the characteristics of performance management systems in the two policy areas are observed to converge. On the basis of a case study, we propose that convergence has occurred due to 1) similarities in policy-specific reforms, 2) institutional pressures, and 3...

  12. Effects of Coriander Essential Oil on the Performance, Blood Characteristics, Intestinal Microbiota and Histological of Broilers

    Directory of Open Access Journals (Sweden)

    S Ghazanfari

    2015-12-01

    Full Text Available ABSTRACT Present study was conducted to investigate the effects of the dietary supplementation of coriander oil on broiler performance, blood characteristics, microbiota, and small intestine morphology measurements. A number of one-day-old broiler chickens (Ross 308 were allocated to five treatments, with four replicates according to a completely randomized design (CRD. Birds were offered either a corn-soybean meal basal diet (control, or the basal diet supplemented with 600 mg/kg of a flavophospholipol antibiotic, 100, 200, or 300 mg/kg coriander essential oil. At 42 days of age, two birds per replicate were selected for blood collection, slaughtered, and its intestinal microbiota and morphology were investigated. The results indicated that weight gain, feed intake, and feed conversion ratio significantly improved by the dietary inclusion of the coriander oil and antibiotic compared with the control treatment (p0.05. Birds fed the coriander oil and antibiotic diets had lower populations of Escherichia coli than control group in cecum (p<0.05. The dietary treatments influenced the morphology of small intestinal villi. Birds fed antibiotic and coriander essential oil presented higher villus height and crypt depth compared with those in the control treatment (p<0.01. Coriander essential oil supplementation significantly decreased epithelial thickness and the number of goblet cell of the small intestinal compared with the control treatment (p<0.0001. In conclusion, coriander oil was shown to be an efficient growth promoter. The intestinal health improvement obtained with coriander oil was associated with improvements in broiler growth performance.

  13. Athlete Characteristics and Team Competitive Performance as Moderators for the Relationship Between Coach Transformational Leadership and Athlete Performance.

    Science.gov (United States)

    Bormann, Kai C; Schulte-Coerne, Paul; Diebig, Mathias; Rowold, Jens

    2016-06-01

    The goal of this study is to examine the effects of coaches' transformational leadership on player performance. To advance existing research, we examine (a) effects on individual and team performance and (b) consider joint moderating effects of players' win orientation and teams' competitive performance on the leadership- individual performance link. In a three-source sample from German handball teams, we collected data on 336 players and 30 coaches and teams. Results showed positive main effects of transformational leadership's facet of articulating a vision (AV) on team and individual performance and negative main effects of providing an appropriate model (PAM) on team performance. With regard to moderating effects, AV increased and PAM decreased individual performance when both moderators were low, and intellectual stimulation had a positive effect when both were high. This study expands insights into the potential and limitation of transformational leadership with a strong focus on the role of situational contingencies.

  14. Evaluation of Performance and Emission characteristics of Turbocharged Diesel Engine with Mullite as Thermal Barrier Coating

    Directory of Open Access Journals (Sweden)

    P. N. Shrirao

    2011-06-01

    Full Text Available Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3 .2SiO2 (mullite (Al2O3= 60%, SiO2= 40% over a 150 μm thickness of NiCrAlY bond coat. Tests were carried out on standard engine (uncoated and low heatrejection (LHR engine with and without turbocharger. This paper is intended to emphasis on energy balance and emission characteristic for standard engine (uncoated and low heat rejection (LHR engine with and without turbocharger. Tests were carried out at different engine load and engine speed conditions for standard and low heatrejection engine with and without turbocharger. The results showed that there was 2.18% decreasing on specific fuel consumption value of low heat rejection (LHR engine with turbocharger compared to standard engine at full load. There was as much as 12% increasing on exhaust gas temperature of LHR engine with turbocharger compared tostandard engine at full load. There was as much as 20.64% increasing on NOx emission of exhaust gas, 22.05% decreasing on CO emission of exhaust gas and 28.20% decreasing on HC emission of exhaust gas of LHR engine with turbocharger compared to standard engine at full load.

  15. Resistive switching characteristics of Pt/TaOx/HfNx structure and its performance improvement

    Directory of Open Access Journals (Sweden)

    Qigang Zhou

    2013-03-01

    Full Text Available The refractory transition metal nitride (TMN film Hafnium nitride (HfNx was successfully prepared on silicon-based substrates as bottom electrodes for resistive random access memory (RRAM cells in Pt (top/metal oxide/ HfNx (bottom sandwich structure. The reproducible resistive switching (RS characteristics of the memory cells were studied systematically for RRAM applications. The advantages of adopting HfNx instead of Pt as bottom electrode material were demonstrated, including the improvement of the low resistive state value, the RS endurance and the uniformity of RS parameters. The composition and chemical bonding states of the prepared HfNx was analyzed by X-ray photoelectron spectroscopy (XPS technique. The nitrogen content in the HfNx and the Gibbs free energy of the corresponding metal oxide formation has great influences on the RS properties. The oxygen reservoir ability and diffusion barrier effect of the HfNx play a key role in the RS performance improvement of the RRAM devices.

  16. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

    Science.gov (United States)

    Varshnay, N. K.; Singh, A.; Benerji, N. S.

    2017-02-01

    Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

  17. Multiple performance characteristics optimization for Al 7075 on electric discharge drilling by Taguchi grey relational theory

    Science.gov (United States)

    Khanna, Rajesh; Kumar, Anish; Garg, Mohinder Pal; Singh, Ajit; Sharma, Neeraj

    2015-05-01

    Electric discharge drill machine (EDDM) is a spark erosion process to produce micro-holes in conductive materials. This process is widely used in aerospace, medical, dental and automobile industries. As for the performance evaluation of the electric discharge drilling machine, it is very necessary to study the process parameters of machine tool. In this research paper, a brass rod 2 mm diameter was selected as a tool electrode. The experiments generate output responses such as tool wear rate (TWR). The best parameters such as pulse on-time, pulse off-time and water pressure were studied for best machining characteristics. This investigation presents the use of Taguchi approach for better TWR in drilling of Al-7075. A plan of experiments, based on L27 Taguchi design method, was selected for drilling of material. Analysis of variance (ANOVA) shows the percentage contribution of the control factor in the machining of Al-7075 in EDDM. The optimal combination levels and the significant drilling parameters on TWR were obtained. The optimization results showed that the combination of maximum pulse on-time and minimum pulse off-time gives maximum MRR.

  18. Revealing the characteristics of a novel bioflocculant and its flocculation performance in Microcystis aeruginosa removal

    Science.gov (United States)

    Sun, Pengfei; Hui, Cai; Bai, Naling; Yang, Shengmao; Wan, Li; Zhang, Qichun; Zhao, Yuhua

    2015-12-01

    In the present work, a novel bioflocculant, EPS-1, was prepared and used to flocculate the kaolin suspension and Microcystis aeruginosa. We focused on the characteristics and flocculation performance of EPS-1, especially with regard to its protein components. An important attribute of EPS-1 was its protein content, with 18 protein types identified that occupied a total content of 31.70% in the EPS-1. Moreover, the flocculating activity of these protein components was estimated to be no less than 33.93%. Additionally, polysaccharides that occupied 57.12% of the total EPS-1 content consisted of four monosaccharides: maltose, D-xylose, mannose, and D-fructose. In addition, carbonyl, amino, and hydroxyl groups were identified as the main functional groups. Three main elements, namely C1s, N1s, and O1s, were present in EPS-1 with relative atomic percentages of 62.63%, 24.91%, and 10.5%, respectively. Zeta potential analysis indicated that charge neutralization contributed to kaolin flocculation, but was not involved in M. aeruginosa flocculation. The flocculation conditions of EPS-1 were optimized, and the maximum flocculating efficiencies were 93.34% within 2 min for kaolin suspension and 87.98% within 10 min for M. aeruginosa. These results suggest that EPS-1 could be an alternative to chemical flocculants for treating wastewaters and cyanobacterium-polluted freshwater.

  19. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-05

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

  20. Performance and carcass characteristics of young cattle fed with soybean meal treated with tannins.

    Science.gov (United States)

    Mezzomo, Rafael; Paulino, Pedro Veiga Rodrigues; Barbosa, Marcília Medrado; da Silva Martins, Taiane; Paulino, Mario Fonseca; Alves, Kaliandra Souza; Gomes, Daiany Iris; Dos Santos Monnerat, João Paulo Ismério

    2016-06-01

    This study aimed to evaluate the effects of replacement of soybean meal (SBM) with soybean meal treated with tannin (SBMT) on the intake, digestibility, performance and characteristics of the carcasses of young cattle fed a high-concentrate diet. Forty-two Nellore bulls with body weight of 244.5 ± 4.99 kg were used. Diets had the inclusion of 7.5% SBM, with a proportion of that SBM (0, 33, 66 or 100%) replaced for SBMT; and other treatment (SBMT + urea) just with 2.5% of SBM which was treated with tannins. Seven animals were randomly selected and slaughtered, and the remaining animals were distributed on treatments and remained for 112 days. After, all animals were slaughtered. There was a linear decline in dry matter intake (P = 0.026) when SBM was replaced with SBMT. No decrease in carcass weight (P > 0.05) was observed. The efficiency of carcass weight gain showed a quadratic function effect (P = 0.049). There were changes in carcass gain composition when SBMT was added (P < 0.05), with an increase in muscle and reduction in fat deposition. The use of SBMT in place of SBM causes changes in body gain composition in animals and reduces DM intake by the animals, achieving a better feed conversion efficiency.

  1. Co-crystallization: An approach to improve the performance characteristics of active pharmaceutical ingredients

    Directory of Open Access Journals (Sweden)

    Jignasa Ketan Savjani

    2015-01-01

    Full Text Available Co-crystal chemistry has recently attracted supramolecular scientists. Co-crystals are comprising of hydrogen boding assembly between different molecules. Many issues related to performance characteristics of an active pharmaceutical ingredient (API can be resolved using co-crystallization approach. Proper understanding of crystal structure of an API is required for successful formation of co-crystals with the selected co-former. This review article focus on explanation about co-crystals, intellectual property rights, their advantages and limitations. Co-crystallization can be achieved using different methods like co-grinding slurry based, solvent evaporation method, etc. Methods of co-crystallization are simple and increase the purity of the final product. Co-crystallization can be applied to the drugs prescribed in combination therapy. Stoichiometric composition of different drugs used in combination therapy can be co-crystallize to form one solid state form. Physicochemical properties of APIs such as solubility and stability can be improved using co-crystallization approach. With due regards co-crystallization should be used with caution because of some issues during manufacturing of final product.

  2. Anthropometric profile and physical performance characteristic of the Brazilian amputee football (soccer team

    Directory of Open Access Journals (Sweden)

    Mário A. M. Simim

    2013-09-01

    Full Text Available Amputee football is a variation of conventional soccer in which athletes with lower limb amputation and one athelete with upper limb amputation (the goalkeeper participate. The objective of this study was to investigate the anthropometric and physical characteristics of amputee football athletes and to verify differences between heart rate peak (HRpeak and equations for predicting maximum heart rate (HRmax. Twelve amputee soccer players from the Brazilian team participated in this study. The body mass, height and body composition were measured. The physical tests used were: the 20 m running test, the T-square test and the Yo Yo intermitent recovery test - level 1 (YYIRT1. The percentage of fat was significantly different between midfielders and defenders. No significant differences were found between positions in the physical tests. The HRpeak was significantly lower than all of HRmax prediction equations tested. We conclude that the indicators of physical performance did not differ significantly between the different tactics roles of players, and that, after intermittent maximum effort, the cardiac response was lower when compared with the investigated HRmax prediction equations.

  3. Characteristics of Crack Growth in High Performance Concrete Subjected to Fire

    Institute of Scientific and Technical Information of China (English)

    Gaifei PENG; Sammy Yin Nin CHAN; Jianhua YAN; Yefeng LIU; Quanxin YI

    2005-01-01

    An experimental investigation was conducted to identify the characteristics of crack growth in high performance concrete (HPC) subjected to fire, including two parts of work, I.e. Crack growth resistance determinations and cracking observations, using concrete of three strength grades 40 Mpa, 70 Mpa, and 110 Mpa. The crack growth resistance curves (R-curves) of HPC subjected to high temperatures were determined using notched three-point bend beam specimens of 100 mm×100 mm×300 mm. The R-curve (crack growth resistance curve) flattening shows that the crack growth resistance has been significantly reduced by elevated temperature. Concrete with a higher strength grade has a steeper R-curve, with a higher fracture toughness but a shorter critical crack growth. The shorter critical crack growth means that concrete of a higher strength grade has a more brittle behavior. The concrete cracking observations reveal that the consequences of rapid heating are quite different from those of slow heating. For slow heating at a rate of 0.5℃/min, HPC suffered no obvious cracking below 600℃ even if it had a high moisture content. Explosive spalling is an extreme case of the internal cracking driven mainly by vapor pressure. All these results confirmed the vapor pressure mechanism for spalling behavior which should be more significant for denser concrete. The crack growth ranges obtained from the R-curve determination results are in good agreement with those measured in the concrete cracking observations.

  4. Performance and emission characteristics of compression ignition engine operating with false flax biodiesel and butanol blends

    Directory of Open Access Journals (Sweden)

    Mustafa Atakan Akar

    2016-02-01

    Full Text Available In this study, fuel properties, engine performance, and emission characteristics of diesel fuel, false flax biodiesel, and their blends with butanol have been evaluated. Blend ratios used in this study were diesel–biodiesel–butanol (70% diesel–20% biodiesel–10% butanol and 60% diesel–20% biodiesel–20% butanol by volume and biodiesel–diesel (20% biodiesel–80% diesel and 100% biodiesel by volume. Experiments showed that 10% alcohol addition to diesel and biodiesel fuels caused a decrease in torque value up to 8.57%. When butanol ratio raised to 20%, torque value decreased to an average of 12.7% and power values decreased to an average of 13.57%. Specific fuel consumption increased to an average of 10.63% and 12.80% with 10% and 20% butanol addition, respectively. Alcohol addiction into conventional diesel and biodiesel fuel slightly increased NOX emissions. Supplement of alcohol decreased CO and CO2 emissions when it was entrained to diesel and increased it when it was added to biodiesel. It means that addition of alcohol to diesel changed CO and CO2 emissions.

  5. Characteristics and Performance of Novel Water-Absorbent Slow Release Nitrogen Fertilizers

    Institute of Scientific and Technical Information of China (English)

    HE Xu-sheng; LIAO Zong-wen; HUANG Pei-zhao; DUAN Ji-xian; GE Ren-shan; LI Hong-bo; GENG Zeng-chao

    2007-01-01

    In this article, a research on the characteristics and performance of water-absorbent slow release nitrogen fertilizer (WASRNF)using infrared spectroscopy (IR), scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA), was present. The results indicate that the water absorbency and nitrogen analysis of WASRNF is 103 g g-1 and 30%, respectively, and WASRNF exhibits approximately neutral pH and very low salt index.WASRNF is a copolymer of nitrogen fertilizer and super absorbent polymer (SAP) monomers which is formed through hydrogen bond interaction, and the molecule contains hydrophilic groups, which is responsible for the absorption and water retention capacity of the molecule. WASRNF is a gel that exhibits the ability to swell, but does not dissolve in water.WASRNF shows non-homogenous nature as a whole, but in local zone it is homogenous, the copolymer molecule shows chain network that is the physical structure responsible for absorption and retention of water in WASRNF. The water retained in WASRNF exists as free and nonfreezing bound and freezing bound water states, with the free and the nonfreezing water accounting for more than 95% of water retained in WASRNF, and the nonfreezing bound water for less than 5%. WASRNF functions in delaying the release of nitrogen from it, thereby serving a novel slow release nitrogenous fertilizer.

  6. Characteristics and performance of membrane electrode assemblies with operating conditions in polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong-Hun [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Yoo, Sung Jong [Fuel Cell Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Park, In-Su; Jeon, Tae-Yeol; Cho, Yoon-Hwan; Lim, Ju Wan [World Class University (WCU) program of Chemical Convergence for Energy and Environment, School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), Seoul (Korea, Republic of); Kwon, Oh Joong [Department of Energy and Chemical Engineering, University of Incheon, 12-1 Songdo-dong, Yeonsu-gu, Incheon 406-772 (Korea, Republic of); Yoon, Won-Sub [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Sung, Yung-Eun, E-mail: ysung@snu.ac.k [World Class University (WCU) program of Chemical Convergence for Energy and Environment, School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), Seoul (Korea, Republic of)

    2010-12-30

    The degradation behavior of a membrane-electrode assembly (MEA) was investigated in accelerated degradation tests under constant voltage (0.8 V and 0.7 V) and load cycling (from open circuit voltage to 0.35 V) conditions. Changes in the structural and electrochemical characteristics of MEA after the durability tests give information as to the degradation mechanism of MEAs. The results of cyclic voltammogram and postmortem analysis by X-ray diffraction and high resolution-transmission electron microscopy indicate that the cathode catalyst layers of the MEAs showed no extreme degradation under constant voltage mode, whereas MEAs under repetition of load cycling mode showed very severe degradation after 280 h. However, the single cell performance of the MEA under repetition of load cycling mode was higher than under constant voltage mode. In addition, although the Pt band in the membrane of the MEA under repetition of load cycling mode was observed by field emission scanning electron microscopy, it did not affect the ohmic resistance.

  7. Performance characteristics of a novel radioactive isotope detection and notification system designed for use in hospitals.

    Science.gov (United States)

    Oh Kim, Jong; Huq, M Saiful; Novotny, Josef; Bednarz, Greg; Palatine, Richard; Reilly, Michael; Izadbakhsh, Mark; Paris, Paul; Greenberger, Joel S

    2011-05-01

    Recently, University of Pittsburgh Medical Center (UPMC) Cancer Centers has installed an Emergency Department Notification System (EDNS) in one of its hospitals. This system, manufactured by Thermo Fisher Scientific (Thermo Fisher Scientific, Inc., 81 Wyman Street, Waltham, MA 02454), was designed to discriminate non-medical radioactive isotopes from medical radioactive isotopes routinely used in nuclear medicine and radiation treatments. It is modular in nature and consists of four NaI(Tl) scintillation detectors, a 512 channels multi-channel analyzer, a system controller, and a database-monitoring server. A series of tests were carried out to evaluate the performance characteristics of this system using a variety of radioactive sources of varying activities. These included measurements of minimum detectable activity, detector response distance to various source activities, detector response to different speeds of a moving radioisotope, and single and multiple radioisotope identification and classification. Measured results show that the system is capable of identifying radioactive sources of nominal activity 0.13 MBq (3.5 μCi) and higher in a relatively short period of time (<11.1 s). The database-monitoring server could send an alarm signal to appropriate personnel when the analysis of the results indicated the presence of a non-medical or threat radioisotope. The present paper reports these results.

  8. Performance, carcass and palatability characteristics of Longhorn and other types of cattle.

    Science.gov (United States)

    Adams, N J; Smith, G C; Carpenter, Z L

    1982-07-01

    Performance, carcass and palatability characteristics of Longhorn steers were compared with those of cattle currently popular in the United States-Hereford, Angus, Brahman, Holstein, two-breed crossbred (British beef breed crosses) and three-breed crossbred (1 4 dairy , 1 4 British beef and 1 2 European beef ) steers. Steers were fed roughage, then a growing diet (42 days), then a high energy (89% concentrate) diet (153 to 179 days by breed group) and slaughtered, individually, at USDA Choice finish or, failing that, after 186 days on the finishing diet. Data suggest that Longhorns, compared with types of cattle currently used: (1) are less desirable in physical appearance; (2) gain weight less rapidly, reaching the desired finish and slaughter weight as older animals; (3) convert feed to liveweight less efficiently; (4) deposit less subcutaneous fat, more internal fat, but essentially the same amount of intramuscular fat; (5) are as muscular (longissimus muscle area, estimated percentage of carcass muscle, muscle to bone ratio, muscle to fat ratio); (6) are as desirable in USDA quality grade and yield grade and (7) produce beef that is a palatable.

  9. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

    Indian Academy of Sciences (India)

    N K VARSHNAY; A A SINGH; N S BENERJI

    2017-02-01

    Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C–C energy transfer circuit and thyratron is used as a high-voltage main switch with singlestage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni–Zn ferrite cores. The laser can generate about 150 mJ at ∼100 Hz rep-rate reliably from a discharge volumeof 100 cm$^3$. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

  10. Growth performances and carcass characteristics of veal calves fed acidified whole milk and milk replacer

    Directory of Open Access Journals (Sweden)

    Tedprasit, S.

    2006-09-01

    Full Text Available The objective of this study was to determine the growth performances and carcass characteristics of male veal calves fed at different levels of acidified whole milk and milk replacer. Twenty-four male Holstein- Friesian 75% crossbred calves with an initial average live weight of 35.44±1.73 kg were allotted into 4 groups under a completely randomized design (CRD for 90 days. Group 1 received 100% whole acidified milk (AM, group 2 received 75% AM and 25% milk replacer (MR, group 3 received 50% AM and 50% MR and group 4 received 100% MR. All groups received 10% body weight of liquid diet, 2% live weight of starter feed and ad libitum of rice straw. After 90 days, the calves in group 1 showed the best final live weight (98.33 kg followed by groups 2 (75.08 kg, 3 (70.00 kg and 4 (57.36 kg (P0.05 in the percentage of fore-quarter and hind-quarter between the treatments. Considering production costs, calves in group 1 showed the lowest cost per live weight gain (53.31 baht/kg gain, followed by group 2 (64.39 baht/kg gain, 3 (77.74 baht/kg gain and 4 (116.82 baht/kg gain, respectively.

  11. Biodiesel production from waste cotton seed oil using low cost catalyst: Engine performance and emission characteristics

    Directory of Open Access Journals (Sweden)

    Duple Sinha

    2016-09-01

    Full Text Available Production of fatty acid methyl esters from waste cotton seed oil through transesterification was reported. The GC–MS analysis of WCCO oil was studied and the major fatty acids were found to be palmitic acid (27.76% and linoleic acid (42.84%. The molecular weight of the oil was 881.039 g/mol. A maximum yield of 92% biodiesel was reported when the reaction temperature, time, methanol/oil ratio and catalyst loading rate were 60 °C, 50 min, 12:1 and 3% (wt.%, respectively. The calcined egg shell catalyst was prepared and characterized. Partial purification of the fatty acid methyl esters was proposed for increasing the purity of the biodiesel and better engine performance. The flash point and the fire point of the biodiesel were found to be 128 °C and 136 °C, respectively. The Brake thermal efficiency of WCCO B10 biodiesel was 26.04% for maximum load, specific fuel consumption for diesel was 0.32 kg/kW h at maximum load. The use of biodiesel blends showed a reduction of carbon monoxide and hydrocarbon emissions and a marginal increase in nitrogen oxides (NOx emissions improved emission characteristics.

  12. Intake, performance, and carcass characteristics of lambs fed spineless cactus replacing wheat bran.

    Science.gov (United States)

    Felix, Sabrina Carla Rodrigues; Pessoa, Ricardo Alexandre Silva; Ferreira, Marcelo de Andrade; Soares, Luciana Felizardo Pereira; Silva, Janaina de Lima; de Abreu, Karen Santos Felix; de Melo, Ana Caroline Cerqueira

    2016-02-01

    To assess the intake, digestibility of nutrients, ingestive behavior, performance, and carcass characteristics of feedlot lambs, 36 F1 Santa Ines × Dorper male lambs with an initial average weight of 19.5 ± 0.27 kg were fed with different levels of spineless cactus (0, 33, 66, and 100 %) as a replacement of the wheat bran. The replacement diets had no effect on the intake of dry matter (DM) or crude protein (CP), whose average values were 962 and 140 g/day, respectively. There was a quadratic effect on the intake of digestible organic matter (OM) and the digestibility of DM, CP, neutral detergent fiber (NDF), and non-fiber carbohydrates (NFC). The highest average daily gain (ADG) of 168 g/day was achieved at 58.7 % replacement level. The highest hot and cold carcass weights of 15.4 and 14.5 kg were achieved at 62.4 and 56.9 % replacement levels. For lambs in the feedlot, we recommend replacing wheat bran with up to 58.7 % spineless cactus.

  13. Ultrathin Sicopion Composite Cation-Exchange Membranes: Characteristics and Electrodialytic Performance following a Conditioning Procedure

    Directory of Open Access Journals (Sweden)

    Erik Ayala-Bribiesca

    2012-01-01

    Full Text Available The aim of this work was to investigate the properties of Sicopion membranes: an ultrathin (≈20 μm composite cation-exchange membrane (CEM made from sulphonated poly(ether-ether-ketone (SPEEK containing different levels of sulphonic-functionalized silica particles (SFSPs. Sicopion membranes were conditioned according to the French Normalization Association procedure, consisting in a series of acid and alkaline washes, and their electrodialytic characteristics were compared to an existent commercial food-grade membrane (CMX-SB. Electrical conductivity of Sicopion membranes was higher than that of CMX-SB membranes (9.92 versus 6.98 mS/cm, as well as their water content (34.0 versus 27.6%. As the SFSP level was reduced, the ion-exchange capacity (IEC of Sicopion membranes increased. Concerning their electrodialytic performances, Sicopion membranes presented a lower demineralization rate than CMX-SB membranes (35.9 versus 45.5%, due to an OH− leakage through the pores created by dislodging the SFSP particles during the conditioning procedure.

  14. GROWTH PERFORMANCE AND CARCASS CHARACTERISTICS AS INFLUENCED BY DIFFERENT VARIETIES OF DESI CHICKENS

    Directory of Open Access Journals (Sweden)

    A.W. Sahota, B. M. Bhatti and L. A. Akhtar

    2003-04-01

    Full Text Available This study was conducted to examine performance and carcass characteristics of different varieties of first generation Desi chickens. The parent Desi chickens were procured from different villages of Mianwali and Bhakkar districts of Punjab, Pakistan and were maintained at Poultry Research Institute, Rawalpindi. Nine hundred day-old chicks (of the first progeny, 300 each of black, dark brown and light brown colour, were obtained from this parent flock. The birds in each variety were divided into 3 equal replicates. They were maintained in 9 separate pens on deep litter under optima.l managemental conditions. The birds were fed ad-libitum a chick starter ration from day-old to 8 weeks and then subsequently a grower mash upto 12 weeks of age. The birds had free access to clean and fresh drinking water. The results showed significant (p<0.0 I variation in dressing percentage, shank and neck length and breast width between different varieties of Desi chickens, whereas, they differed non-significantly in growth rate and keel length. The light brown variety had significantly better dressing percentage, shank length and breast width than other two varieties. whereas neck length in both the brown varieties was significantly better than black Desi chickens. Both the brown varieties differed non-significantly from each other in neck length.

  15. Optimum Efficient Mobility Management Scheme for IPv6

    Directory of Open Access Journals (Sweden)

    Virender Kumar

    2012-10-01

    Full Text Available Mobile IPv6 (MIPv6 and Hierarchical Mobile IPv6 (HMIPv6 both are the mobility management solutionsproposed by the Internet Engineering Task Force (IETF to support IP Mobility. It’s been an importantissue, that upon certain condition, out of MIPv6 and HMIPv6 which one is better. In this paper anOptimum Efficient Mobility Management (OEMM scheme is described on the basis of analytical modelwhich shows that OEMM Scheme is better in terms of performance and applicability of MIPv6 andHMIPv6. It shows that which one is better alternative between MIPv6 and HMIPv6 and if HMIPv6 isadopted it chooses the best Mobility Anchor Point (MAP. Finally it is illustrated that OEMM scheme isbetter than that of MIPv6 and HMIPv6.

  16. Optimum spatiotemporal receptive fields for vision in dim light.

    Science.gov (United States)

    Klaus, Andreas; Warrant, Eric J

    2009-04-22

    Many nocturnal insects depend on vision for daily life and have evolved different strategies to improve their visual capabilities in dim light. Neural summation of visual signals is one strategy to improve visual performance, and this is likely to be especially important for insects with apposition compound eyes. Here we develop a model to determine the optimum spatiotemporal sampling of natural scenes at gradually decreasing light levels. Image anisotropy has a strong influence on the receptive field properties predicted to be optimal at low light intensities. Spatial summation between visual channels is predicted to extend more strongly in the direction with higher correlations between the input signals. Increased spatiotemporal summation increases signal-to-noise ratio at low frequencies but sacrifices signal-to-noise ratio at higher frequencies. These results, while obtained from a model of the insect visual system, are likely to apply to visual systems in general.

  17. Implementation of optimum solar electricity generating system

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Balbir Singh Mahinder, E-mail: balbir@petronas.com.my; Karim, Samsul Ariffin A., E-mail: samsul-ariffin@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Sivapalan, Subarna, E-mail: subarna-sivapalan@petronas.com.my [Department of Management and Humanities, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Najib, Nurul Syafiqah Mohd; Menon, Pradeep [Department of Electrical and Electronics Engineering, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  18. Implementation of optimum solar electricity generating system

    Science.gov (United States)

    Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

    2014-10-01

    Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  19. Influence of higher order need strenght and job characteristics on job performance

    Directory of Open Access Journals (Sweden)

    C. J. H. Blignaut

    1975-11-01

    Full Text Available Contemporary theories of work motivation are classified according to (1 those based on the underlying assumption that all individuals posses higher level need, are capable of satisfying and will indeed satisfy such needs provided the job situation incorporates the conditions or characteristics that make satisfaction possible and (2 those theories suggesting that an individual may or may not be motivated by certain job characteristics depending on whether he in fact has specific (higher level needs to be fulfilled and whether he views the job situation as conductive to need satisfaction. 126 Subjects employed by a chemical industry took part in an experiment designed to test the basic assumptions underlying the aforementioned theories. Data relating to higher order need satisfaction, the psychological value of job content and job performance served as input to a 2X2 factorial analysis. Results indicate that only the psychological value of job content represented a significant source of variation (p is smaller as ,01 - a finding which favours category (1 theories to a large extent. No significant interaction between the latter source of variation and higher order need satisfaction could be found.Opsomming Kontemporêre motiveringsteorieë in die Bedryfsielkunde word geklassifiseer in twee groepe naamlik (1 dié wat berus op die basiese aanname dat alle werknemers hoëvlak behoeftes het en die bevrediging daarvan sal nastreef solank die inhoud van die werk dit moontlik maak en (2 dié wat op die aanname berus dat sielkundig gunstige werksinhoud waarskynlik hoëvlak behoeftebevrediging tot gevolg sal hê, afhangende van hoe die individu die werksituasie waarneem. 126 Werknemers in 'n Suid-Afrikaanse chemiese nywerheid is by 'n eksperiment betrek waarin bogenoemde basiese aannames teenoor mekaar gestel is. Data ten opsigte van die sielkundige waarde van werksinhoud, hoëvlak behoeftebevrediging en werksprestasie dien as inset tot 'n 2x2 faktoriale

  20. Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education

    Science.gov (United States)

    Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

    2014-01-01

    Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking…