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Sample records for achievement performances stagnate

  1. Athlete atypicity on the edge of human achievement: performances stagnate after the last peak, in 1988.

    Directory of Open Access Journals (Sweden)

    Geoffroy Berthelot

    Full Text Available The growth law for the development of top athletes performances remains unknown in quantifiable sport events. Here we present a growth model for 41351 best performers from 70 track and field (T&F and swimming events and detail their characteristics over the modern Olympic era. We show that 64% of T&F events no longer improved since 1993, while 47% of swimming events stagnated after 1990, prior to a second progression step starting in 2000. Since then, 100% of swimming events continued to progress.We also provide a measurement of the atypicity for the 3919 best performances (BP of each year in every event. The secular evolution of this parameter for T&F reveals four peaks; the most recent (1988 followed by a major stagnation. This last peak may correspond to the most recent successful attempt to push forward human physiological limits. No atypicity trend is detected in swimming. The upcoming rarefaction of new records in sport may be delayed by technological innovations, themselves depending upon economical constraints.

  2. Achieving optimal business performance through business practices ...

    African Journals Online (AJOL)

    Achieving optimal business performance through business practices: ... it is often articulated that best business practices produce superlative business performance. ... strategic planning practices, human resource management practices, risk ...

  3. Achieving optimal business performance through business practices ...

    African Journals Online (AJOL)

    Kirstam

    management practices, risk management practices, performance ... 1As businesses constantly seek out new and better ways of achieving competitive ..... performance management helps managers to sense uncertain situations earlier and.

  4. Impact of Metacognition on Guitar Performance Achievement

    OpenAIRE

    Yokuş, Tuba

    2013-01-01

    This study has been carried out to determine the impact of the development of metacognition on guitar performance achievement in the individual instrument guitar lesson, which is included in the Bachelor’s program of Music Teacher Education in Marmara University Atatürk Faculty of Education, Department of Fine Arts Education, in Turkey. “Experimental Design with Pretest–Posttest Control Group” has been used, in order to achieve the objective of the study. The study sample (N=10) consists of g...

  5. Achieving High Performance Perovskite Solar Cells

    Science.gov (United States)

    Yang, Yang

    2015-03-01

    Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

  6. Achieving real-time performance in FIESTA

    Science.gov (United States)

    Wilkinson, William; Happell, Nadine; Miksell, Steve; Quillin, Robert; Carlisle, Candace

    1988-01-01

    The Fault Isolation Expert System for TDRSS Applications (FIESTA) is targeted for operation in a real-time online environment. Initial stages of the prototype development concentrated on acquisition and representation of the knowledge necessary to isolate faults in the TDRSS Network. Recent efforts focused on achieving real-time performance including: a discussion of the meaning of FIESTA real-time requirements, determination of performance levels (benchmarking) and techniques for optimization. Optimization techniques presented include redesign of critical relations, filtering of redundant data and optimization of patterns used in rules. Results are summarized.

  7. Achieving high performance on the Intel Paragon

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, D.S.; Maccabe, B.; Riesen, R.; Wheat, S.; Womble, D.

    1993-11-01

    When presented with a new supercomputer most users will first ask {open_quotes}How much faster will my applications run?{close_quotes} and then add a fearful {open_quotes}How much effort will it take me to convert to the new machine?{close_quotes} This paper describes some lessons learned at Sandia while asking these questions about the new 1800+ node Intel Paragon. The authors conclude that the operating system is crucial to both achieving high performance and allowing easy conversion from previous parallel implementations to a new machine. Using the Sandia/UNM Operating System (SUNMOS) they were able to port a LU factorization of dense matrices from the nCUBE2 to the Paragon and achieve 92% scaled speed-up on 1024 nodes. Thus on a 44,000 by 44,000 matrix which had required over 10 hours on the previous machine, they completed in less than 1/2 hour at a rate of over 40 GFLOPS. Two keys to achieving such high performance were the small size of SUNMOS (less than 256 kbytes) and the ability to send large messages with very low overhead.

  8. An unsteady stagnation-point flow

    Science.gov (United States)

    Riley, N.; Vasantha, R.

    1989-11-01

    The oscillatory flow at a two-dimensional stagnation point is studied. It is shown that, following the initiation of the motion, the solution always develops a singularity at a finite time. The implications of this finding for the flow over a cylinder which performs transverse harmonic oscillations are discussed.

  9. Achievement Goals and Performance in English and Mathematics of ...

    African Journals Online (AJOL)

    Achievement Goals and Performance in English and Mathematics of Senior ... and Avoidance Achievement Motivation” scale as measure of achievement goals ... the goals, between learning and performance-avoidance goals with English ...

  10. Achieving scale strategies for sustained competitive performance.

    Science.gov (United States)

    Grube, Mark E; Gish, Ryan S; Tkach, Sasha N

    2008-05-01

    Growth to achieve scale requires the following strategic initiatives: Having a clear understanding of what the organization is and what it wants to become. Ensuring a structured and rigorous growth process. Leveraging size to achieve benefits of scale. Recognizing the importance of physicians, ambulatory care, and primary care. Establishing and maintaining accountability as growth occurs.

  11. On Achievable Performance of Cognitive Radio Systems

    CERN Document Server

    Haddad, Majed; Hayar, Aawatif Menouni

    2007-01-01

    In this contribution, we investigate the idea of using cognitive radio to reuse locally unused spectrum to increase the total system capacity. We consider a multiband/wideband system in which the primary and cognitive users wish to communicate to different receivers, subject to mutual interference and assume that each user knows only his channel and the unused spectrum through adequate sensing. Under this scheme, a cognitive radio will listen to the channel and, if sensed idle, will transmit during the voids. Within this setting, we provide two simple methods for sensing the idle sub-bands over the total bandwidth. We impose the constraint that users successively transmit over available bands through proper water filling. For the first time, our study has quantified the achievable gain of using cognitive radio with respect to classical radio devices and derive the total spectral efficiency as well as the maximum number of possible pairwise communications of such a cognitive radio system. We finally show that ...

  12. 'High' achievers? Cannabis access and academic performance

    NARCIS (Netherlands)

    Marie, O.; Zölitz, U.N.

    2015-01-01

    This paper investigates how legal cannabis access affects student performance. Identification comes from an exceptional policy introduced in the city of Maastricht which discriminated legal access based on individuals’ nationality. We apply a difference in-difference approach using administrative pa

  13. 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.

  14. Performance of Thermal Radiation Energy on Stagnation-Point Flow In The Presence of Water Based Copper and Single Walled Carbon Nanotubes over Stretching/Shrinking Sheet

    Directory of Open Access Journals (Sweden)

    R. Kandasamy

    2016-04-01

    Full Text Available This article is expected for analyzing the impact of mixed convection flow of water based copper and single walled carbon nanotubes on a stagnation-point flow over a porous stretching/shrinking sheet subject to thermal energy radiation by utilizing numerical method. The governing PDEs are converted into nonlinear ODEs by using similarity transformation which is solved numerically using fifth-order Runge–Kutta–Fehlberg method with shooting technique (MAPLE 18. Both stretching and shrinking sheets, the influences of governing parameters are analyzed in graphical and tabular form and found that the SWCNTs–water exhibits higher mass transfer rates compared to Cu–water nanofluids with increase of chemical reaction.

  15. The stagnation of international law

    NARCIS (Netherlands)

    Pauwelyn, Joost; Wessel, Ramses A.; Wouters, Jan

    2012-01-01

    Traditional international law and its instruments are stagnating both in terms of quantity and quality. New, alternative forms of cross-border cooperation, in particular processes of informal international lawmaking, have emerged and gained prominence since the 2000s in response to an increasingly

  16. Total Performance Scorecard Redefining Management to Achieve Performance with Integrity

    CERN Document Server

    Rampersad, Hubert

    2003-01-01

    In the post-Enron climate corporate executives are increasingly pressured to increase productivity and create an ethical, trustworthy organizational climate. 'Total Performance Scorecard' introduces a concept of organizational improvement and change management that combines the Balanced Scorecard model with the learning organization theory. The TPS contains a personal balanced scorecard, which is tied to an organizational balanced scorecard. These scorecards reflect not only performance goals but personal learning and growth goals as well, and the organizational scorecards also address organiz

  17. Test Drive: Six States Pilot Better Ways to Measure and Compare Community College Performance. An Achieving the Dream Policy Brief

    Science.gov (United States)

    Jobs for the Future, 2008

    2008-01-01

    Increasing demand for at least some postsecondary education in today's labor market has met with stagnating college completion rates. As a result, states have a growing interest in better understanding the challenges to improving graduation rates and in tracking student progress and success. Six states in the "Achieving the Dream: Community…

  18. [Memory performance and general achievement motivation in the aged].

    Science.gov (United States)

    Heineken, E; Gekeler, C

    1985-01-01

    Memory achievement is generally confounded with motivational factors in memory research. Therefore, the interpretation of age specific differences in recall renders difficult. The effect of a mnemonic device (method of loci) on recall is studied in a multitrial free recall experiment with 48 seniors aged from 60 to 92. Recall, performance in "Pauli"-tasks as an indicator of general achievement motivation, and subjective organization are measured. The experiment is planned as a three-factorial randomized group design with the factors "mnemonic device", "age", and "concreteness of learning material". The mnemonic device has a strong effect on recall as well as on performance "Pauli"-tasks. Its effect on recall is attributed to the increased achievement motivation.

  19. Achieving High Performance on the i860 Microprocessor

    Science.gov (United States)

    Lee, King; Kutler, Paul (Technical Monitor)

    1998-01-01

    The i860 is a high performance microprocessor used in the Intel Touchstone project. This paper proposes a paradigm for programming the i860 that is modelled on the vector instructions of the Cray computers. Fortran callable assembler subroutines were written that mimic the concurrent vector instructions of the Cray. Cache takes the place of vector registers. Using this paradigm we have achieved twice the performance of compiled code on a traditional solve.

  20. The Relationship Between Intellectual-Achievement Responsibility Attributions and Performance.

    Science.gov (United States)

    Barnett, Mark A.; Kaiser, Donn L.

    The relationship between a child's assumption of responsibility for intellectual-academic successes and failures and various performance scores was examined in the present investigation. An expanded version of the Crandall, Katkovsky, and Crandall (1967) Intellectual Achievement Responsibility (IAR) Questionnaire was administered to a total of 138…

  1. School Performance Indicators, Accountability Ratings, and Student Achievement

    Science.gov (United States)

    Jackson, Shirley A.; Lunenburg, Fred C.

    2010-01-01

    Researchers have been challenged to find school-level characteristics that make a difference in student achievement. This study focused on a diverse sample of 24 middle schools to examine differences between schools rated Exemplary, Recognized, Academically Acceptable, and Academically Unacceptable on four performance indicator dimensions:…

  2. Attentional performance, age and scholastic achievement in healthy children.

    Directory of Open Access Journals (Sweden)

    Mireille Trautmann

    Full Text Available BACKGROUND: Attentional processes in children play a critical role in daily school demands and accomplishments. Studies on the association of attentional processes with school achievement and age in healthy school children are scarce. The aim of the present study was to identify correlations between dimensions of attentional performance, scholastic achievement and age. METHODOLOGY/PRINCIPAL FINDINGS: An extensive testing battery was used to assess a wide range of attentional dimensions. A principal component analysis revealed three factors that are related to attentional performance (distractibility, lapses of attention, cognitive speed. Age was negatively associated with distractibility, lapses of attention and cognitive speed, indicating that distractibility and lapses of attention decreased with age in healthy children and resulted in lower cognitive speed. CONCLUSIONS/SIGNIFICANCE: Attentional processes in healthy children should be measured in relation to distractibility, lapses of attention and cognitive speed.

  3. Metrics help rural hospitals achieve world-class performance.

    Science.gov (United States)

    Goodspeed, Scott W

    2006-01-01

    This article describes the emerging trend of using metrics in rural hospitals to achieve world-class performance. This trend is a response to the fact that rural hospitals have small patient volumes yet must maintain a profit margin in order to fulfill their mission to the community. The conceptual idea for this article is based largely on Robert Kaplan and David Norton's Balanced Scorecard articles in the Harvard Business Review. The ideas also come from the experiences of the 60-plus rural hospitals that are using the Balanced Scorecard and their implementation of metrics to influence performance and behavior. It is indeed possible for rural hospitals to meet and exceed the unique needs of patients and physicians (customers), to achieve healthy profit margins, and to be the rural hospital of choice that employees are proud to work for.

  4. The Role Of The Budgetary System In Achieving Enterprise Performance

    Directory of Open Access Journals (Sweden)

    Adriana Mihaela Ionescu

    2014-05-01

    Full Text Available The long-term existence of an enterprise can only be assured by achieving of the performance.In the current economic climate, the companies pay more attention to effective management of resources and use for this purpose different management tools of performance. Along with material and financial resources necessary to productive activities, the people in an organization represent more than a source of cost or consumption. Their systems of needs and values, along with degrees of motivation and satisfaction determine individual and organizational performance. This is why the managers are tasked to reconcile and correlate the economic performance of the organization with the skills and capabilities of the employees. Flexible approach to business organization and permanent training of the human resources are the ingredients of success of an enterprise that aims to adapt to the current business environment changes.

  5. 晋升机会缺失对员工工作绩效的影响--内在动机与内部地位感知的中介作用%Promotion Opportunity Stagnation and Job Performance:the Mediating---Role of Intrinsic Motivation and Perceived Insider Status

    Institute of Scientific and Technical Information of China (English)

    廖建桥; 景珍思; 刘文兴; 汪兴东

    2015-01-01

    This study tries to explore the side back of promotion opportunity stagnation, assuming that promotion opportunity stagnation should be one important factor of inhibiting employee j ob performance,and that the effect of promotion opportunity stagnation on j ob performance should be mediated by intrinsic motivation and perceived insider status.By the answers to the questionnaires and the analysis of 354 samples from a large installation company in China,the results indicated that,(1 )promotion opportunity stagnation had negative effects on employee j ob performance;(2 )promotion opportunity stagnation had negative effects on intrinsic motivation and perceived insider status;(3 )both intrinsic motivation and perceived insider status had positive effects on employee j ob performance;(4 )both intrinsic motivation and perceived insider status fully mediated the relationship between promotion opportunity stagnation and j ob performance.At last,we discuss implications of these results for research and practice and future directions.%探讨晋升机会缺失的负面影响,认为晋升机会缺失是阻碍员工工作绩效提升的重要影响因素,且晋升机会缺失是通过内在动机与内部地位感知最终影响到员工工作绩效。通过对来自一家大型安装企业的354名员工实证分析结果表明:①晋升机会缺失会显著降低员工工作绩效;②晋升机会缺失会显著降低内在动机与内部地位感知;③内在动机、内部地位感知显著正面影响员工工作绩效;④晋升机会缺失通过内在动机、内部地位感知,进而降低员工工作绩效。最后,讨论了相关理论和实践的启示以及未来的研究方向。

  6. Achievement goals and championship performance: Predicting absolute performance and qualification success

    OpenAIRE

    Stoeber, Joachim; Crombie, Rosanna

    2010-01-01

    Objectives: Research on athletes’ achievement goals has suggested that the contrast between performance approach and performance avoidance goals (performance approach-avoidance contrast) is a significant predictor of sports performance. However, so far only two studies investigating triathletes found that performance approach-avoidance contrast predicted sports performance in competitions. The present study aims to replicate and expand on these findings with a diverse sample of track and fiel...

  7. Magnetic fusion: progress -> stagnation -> degradation

    Science.gov (United States)

    Zakharov, Leonid

    2012-10-01

    ``The theory of the failure of magnetic fusion,'' created in 2004 and presented to APS-2007 introduced the notion of the ``difficult'' and ``complicated'' stages of the program and described them details. At the first phase the emerging fusion science was created under strong leadership. Progress was visible on year to year basis, and the program was easy to manage. The complicated phase started in the late 1980s, when the plasma physics appeared to be incapable to implement the mission of ITER to test nuclear components of a fusion reactor. Then, the failure of TFTR (PPPL, USA) and JET (Culham, UK) in the mid 1990 to demonstrate QDT=1 and the blindness of their leaders to already visible means to resolve the problem, were a clear indication of an irreversible stagnation. In fact, right after 2007, it became clear that in the case of a large system of human ``particles'' (scientists) two phases have a continuation. The internal degrees of freedom, otherwise protected from external perturbations by a strong dedication to the scientific method, are now eroding and collapsing. The loss of science in addressing confinement, stability, power extraction, fueling, stationary regimes issues makes the current program irrelevant to fusion energy. A fresh approach should be taken.

  8. How to Achieve Quality Business Performance in an Organization

    Directory of Open Access Journals (Sweden)

    Merima Bekri ć

    2013-02-01

    Full Text Available RQ: The research question is the influence of quality management on quality business performance.Purpose: Determine which top management approaches are essential for business excellence and leadership approaches that achieve quality business.Method: Analysis of articles from the Journal Organization from the last 5 years and one article from the Journal of Universal Excellent to obtain data.Results: Characteristics of managers and individual employees influence the quality of an organization's performance and business excellence. This is rudimentary for an organization to perform successfully. The results show the weaknesses that an organization can improve in.Organization: The research study facilitates in improving long-term success of an organization. The results can assist in further decision-making and timely responses to changes in its internal and external environment.Society: Better business performance contributes to the wider environment, as this also ensures stability of an organization.Originality: A different approach in viewing management issuesand searching for improvements. There are not many review articles on this topic.Limitations: The analysis was conducted with only ten articles.

  9. Vorticity amplification near the stagnation point of landing gear wheels

    Science.gov (United States)

    Feltham, G.; Ekmekci, A.

    2014-04-01

    The vicinity near the forward stagnation point of landing-gear wheels has been found to support a mechanism for oncoming streams of weak vorticity to collect, grow, and amplify into discrete large-scale vortical structures that then shed with a distinct periodicity. To the authors' knowledge, such a flow phenomenon has never been reported before for landing gear wheels, which are in essence finite (three-dimensional) cylinders. To gain further insight into this phenomenon, a detailed experimental study has been undertaken employing the hydrogen bubble visualization and Particle Image Velocimetry techniques. A very thin platinum wire, similar to those used in hydrogen bubble visualization applications, was placed upstream of the wheel model to produce two streams of weak vorticity (with opposite sign) that convected toward the model. As the vorticity streams enter the stagnation region of the wheels, significant flow deceleration and vorticity stretching act to collect, grow, and amplify the incoming vorticity streams into large-scale vortical structures. Experiments were performed at a fixed Reynolds number, with a value of 32 500 when defined based on the diameter of the wheel and a value of 21 based on the diameter of the vorticity-generating upstream wire. First, to establish a baseline, the natural flow field (without the presence of an upstream wire) was characterized, where experimentally determined values for the stagnation boundary-layer thickness and the velocity profile along the stagnation streamline were both found to agree with the values provided in the literature for two-dimensional cylinders. Subsequently, the dynamics of vorticity collection, growth, amplification, and shedding were studied. The size, stand-off distance and the shedding frequency of the vortical structures forming near the stagnation region were all found to strongly depend on the impingement location of the inbound vorticity on the wheel. A simple relationship between the non

  10. Science Achievement for All: Improving Science Performance and Closing Achievement Gaps

    Science.gov (United States)

    Jackson, Julie K.; Ash, Gwynne

    2012-01-01

    This article addresses the serious and growing need to improve science instruction and science achievement for all students. We will describe the results of a 3-year study that transformed science instruction and student achievement at two high-poverty ethnically diverse public elementary schools in Texas. The school-wide intervention included…

  11. Approximate Model for Turbulent Stagnation Point Flow.

    Energy Technology Data Exchange (ETDEWEB)

    Dechant, Lawrence [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    Here we derive an approximate turbulent self-similar model for a class of favorable pressure gradient wedge-like flows, focusing on the stagnation point limit. While the self-similar model provides a useful gross flow field estimate this approach must be combined with a near wall model is to determine skin friction and by Reynolds analogy the heat transfer coefficient. The combined approach is developed in detail for the stagnation point flow problem where turbulent skin friction and Nusselt number results are obtained. Comparison to the classical Van Driest (1958) result suggests overall reasonable agreement. Though the model is only valid near the stagnation region of cylinders and spheres it nonetheless provides a reasonable model for overall cylinder and sphere heat transfer. The enhancement effect of free stream turbulence upon the laminar flow is used to derive a similar expression which is valid for turbulent flow. Examination of free stream enhanced laminar flow suggests that the rather than enhancement of a laminar flow behavior free stream disturbance results in early transition to turbulent stagnation point behavior. Excellent agreement is shown between enhanced laminar flow and turbulent flow behavior for high levels, e.g. 5% of free stream turbulence. Finally the blunt body turbulent stagnation results are shown to provide realistic heat transfer results for turbulent jet impingement problems.

  12. Why did Danish women's life expectancy stagnate?

    DEFF Research Database (Denmark)

    Lindahl-Jacobsen, Rune; Oeppen, James; Rizzi, Silvia

    2016-01-01

    -attributable mortality was excluded, the gap in partial life expectancy at age 50 between Swedish and Danish women diminished substantially. The effect was most pronounced in the interwar generations. The major reason for the stagnation in Danish women's partial life expectancy at age 50 was found to be smoking......The general health status of a population changes over time, generally in a positive direction. Some generations experience more unfavourable conditions than others. The health of Danish women in the interwar generations is an example of such a phenomenon. The stagnation in their life expectancy...... between 1977 and 1995 is thought to be related to their smoking behaviour. So far, no study has measured the absolute effect of smoking on the mortality of the interwar generations of Danish women and thus the stagnation in Danish women's life expectancy. We applied a method to estimate age...

  13. Public debt, secular stagnation and functional finance

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    Fiscal policy and public debt may be required to maintain full employment and avoid secular stagnation. This conclusion emerges from a range of different models, including OLG specifications and stock-flow consistent (post-) Keynesian models. One of the determinants of the required long-run debt ...

  14. Aggregate demand, functional finance and secular stagnation

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    This paper makes three main points. Fiscal policy, first, may be needed in the long run to maintain full employment and avoid secular stagnation. If fiscal policy is used in this way, second, the long-run debt ratio depends (i) inversely on the rate of growth, (ii) inversely on government consump...

  15. Aggregate demand, functional finance and secular stagnation

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    This paper makes three main points. Fiscal policy, first, may be needed in the long run to maintain full employment and avoid secular stagnation. If fiscal policy is used in this way, second, the long-run debt ratio depends (i) inversely on the rate of growth, (ii) inversely on government...

  16. Achievement Goals, Motivation, and Performance: A Closer Look.

    Science.gov (United States)

    Urdan, Tim; Pajares, Frank; Lapin, Amy Z.

    An achievement goal theory framework was used to examine the relations among goals and a number of other motivational constructs in a sample of middle school students. Participants were 189 eighth graders from a public school in the south. In one session students completed the attitude measures and in another session they completed a mathematics…

  17. Mirror Analysis: How To Achieve Customer-Driven Human Performance.

    Science.gov (United States)

    Mourier, Pierre

    1999-01-01

    Presents an evaluation/development method for achieving customer-driven improvement in organizations. Describes the steps to external and internal "mirror analysis," a process for determining if the organization functions as a mirror of customers' needs and expectations. Twelve figures illustrate factors in the process. (AEF)

  18. Uniting academic achievements on performance analysis with industrial needs

    NARCIS (Netherlands)

    Theelen, Bart; Hooman, Jozef

    2015-01-01

    In our mission to advance innovation by industrial adoption of academic results, we perform many projects with high-tech industries. Favoring formal methods, we observe a gap between industrial needs in performance modeling and the analysis capabilities of formal methods for this goal. After clarify

  19. Cryogenics system: strategy to achieve nominal performance and reliable operation

    CERN Document Server

    Bremer, J; Casas, J; Claudet, S; Delikaris, D; Delruelle, N; Ferlin, G; Fluder, C; Perin, A; Perinic, G; Pezzetti, M; Pirotte, O; Tavian, L; Wagner, U

    2012-01-01

    During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the overcapacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the "cannibalization" of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of ...

  20. ‘High’ Achievers? Cannabis Access and Academic Performance

    NARCIS (Netherlands)

    O. Marie (Olivier); U. Zoelitz (Ulf)

    2016-01-01

    textabstractThis paper investigates how legal cannabis access affects student performance. Identification comes from an exceptional policy introduced in the city of Maastricht in the Netherlands that discriminated access via licensed cannabis shops based on an individual’s nationality. We apply a di

  1. ‘High’ achievers? Cannabis access and academic performance

    NARCIS (Netherlands)

    Marie, O.; Zölitz, U.N.

    2015-01-01

    This paper investigates how legal cannabis access affects student performance. Identification comes from an exceptional policy introduced in the city of Maastricht which discriminated legal access based on individuals’ nationality. We apply a difference-in-difference approach using administrative pa

  2. Three Oil Giants Achieved Good Operating Performances in First Quarter

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ PetroChina announced performance results PetroChina released its operation data for the first quarter this year on April 15th. A manager in PetroChina said that the increase rate of production of PetroChina in the first quarter this year has created the best level since PetroChina registered in HK in 2000.

  3. Stagnation-point combustion with radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, C.M.; Pagni, P.J.

    1981-01-01

    The relatively simple character of diffusion flames in laminar stagnation-point flows has led to numerous theoretical and experimental studies of that system. As a first step toward incorporating radiation in analyses eventually related to fire safety, a grey radiating diffusion flame above a grey pyrolyzing solid fuel is considered. Shvab-Zeldovich variables are used in the analyses of steady, laminar, radiative, axisymmetric and Cartesian two-dimensional stagnation-point boundary layers. The velocity, temperature, and species fields for the case of a uniform absorption coefficient: (1) the exponential kernel and (2) the optically thin limit. The difference between these approximations proved insignificant; the simpler optically thin limit may be the method of choice. The results depend on eight parameters. 12 refs.

  4. Mass Transfer Cooling Near The Stagnation Point

    Science.gov (United States)

    Roberts, Leonard

    1959-01-01

    A simplified analysis is made of mass transfer cooling, that is, injection of a foreign gas, near the stagnation point for two-dimensional and axisymmetric bodies. The reduction in heat transfer is given in terms of the properties of the coolant gas and it is shown that the heat transfer may be reduced considerably by the introduction of a gas having appropriate thermal and diffusive properties. The mechanism by which heat transfer is reduced is discussed.

  5. Measuring the stagnation phase of NIF implosions: reproducibility and intentional asymmetry

    Science.gov (United States)

    Spears, Brian; Benedetti, R.; Callahan, D.; Casey, D.; Eder, D.; Gaffney, J.; Ma, T.; Munro, D.; Knauer, J.; Kilkenny, J.

    2015-11-01

    We report here data from a 5-shot sequence of cryogenic DT layered implosions designed to measure NIF implosion stagnation, the reproducibility of stagnation, and the response of the stagnation phase to intentional perturbation. We emphasize new analysis of the neutron spectral moments. These features provide an experimental measurement of hot spot thermal (temperature) and fluid (residual flow) processes. They also provide strong constraints for code validation. In implosions that were intentionally perturbed by laser drive and DT layer asymmetry, the experimental measurements show clear signs of the damaged stagnation. These signatures also match well our expectations from simulation, reproducing the variation of apparent temperature with line of sight and the down scattered neutron ratio, among others. The suite of implosions provides a demonstration of our ability to measure stagnated flow performance and highlights the several precision diagnostic signatures that are correctly captured by radhydro codes. This work was performed by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. Achieving "Fairness" in Data Fusion Performance Evaluation Development

    Science.gov (United States)

    2006-04-30

    Performance Evaluation Development 5b. GRANT NUMBER F49620-03-1-0037 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Dr. James Llinas 5e...Evaluation Methods for Network Centric Data-Fusion Capable Tactical Platforms Kedar Sambhoos, Satyaki Ghosh Dastidar, James Llinas Christopher Bowman...were based settings were as follows: 8. ensor ID: Sensor matix wer based 1. Targets: 6 targets upon entity class confusion matrix per sensor mode. 2

  7. 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.

  8. Achieving Mixtures of Ultra-High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Mircea POPA

    2013-07-01

    Full Text Available Ultra-High Performance Concrete (UHPC is a relatively new concrete. According to [11] UHPC is that concrete which features compressive strength over C100/115 class. Up to this point standards for this type of concrete were not adopted, although its characteristic strength exceeds those specified in [33]. Its main property is high compressive strength. This provides the possibility of reducing the section of elements (beams or columns made of this type of concrete, while the load capacity remains high. The study consists in blending mixtures of UHPC made of varying proportions of materials. The authors have obtained strengths of up to 160 MPa. The materials used are: Portland cement, silica fume, quartz powder, steel fibers, superplasticiser, sand and crushed aggregate for concrete - andesite.

  9. WEIGHTS STAGNATION IN DYNAMIC LOCAL SEARCH FOR SAT

    Directory of Open Access Journals (Sweden)

    Abdelraouf Ishtaiwi

    2016-05-01

    Full Text Available Since 1991, tries were made to enhance the stochastic local search techniques (SLS. Some researchers turned their focus on studying the structure of the propositional satisfiability problems (SAT to better understand their complexity in order to come up with better algorithms. Other researchers focused in investigating new ways to develop heuristics that alter the search space based on some information gathered prior to or during the search process. Thus, many heuristics, enhancements and developments were introduced to improve SLS techniques performance during the last three decades. As a result a group of heuristics were introduced namely Dynamic Local Search (DLS that could outperform the systematic search techniques. Interestingly, a common characteristic of DLS heuristics is that they all depend on the use of weights during searching for satisfiable formulas. In our study we experimentally investigated the weights behaviors and movements during searching for satisfiability using DLS techniques, for simplicity, DDFW DLS heuristic is chosen. As a results of our studies we discovered that while solving hard SAT problems such as blocks world and graph coloring problems, weights stagnation occur in many areas within the search space. We conclude that weights stagnation occurrence is highly related to the level of the problem density, complexity and connectivity.

  10. Relations among Motivation, Performance Achievement, and Music Experience Variables in Secondary Instrumental Music Students

    Science.gov (United States)

    Schmidt, Charles P.

    2005-01-01

    The purpose of this study was to (1) reexamine academic achievement motivation orientations within the context of instrumental music, and (2) examine relations among achievement motivation orientations, self-concept in instrumental music, and attitude to band in relation to teachers' ratings of performance achievement and effort, and students'…

  11. Experimental and numerical investigation of reacting stagnation flow

    Science.gov (United States)

    Bergthorson, Jeff; Dimotakis, Paul

    2003-11-01

    Planar laminar premixed flames are stabilized in the stagnation flowfield of an impinging jet. These flames are studied experimentally through measurements of the axial velocity and CH radical profiles, the equivalence ratio, plate temperature, and the static (Bernoulli) pressure drop across the nozzle. The velocity measurements are performed using Particle Streak Velocimetry (PSV), a technique valuable in flame measurements due to the low particle-mass loading, high accuracy and short run times possible. The CH radical profile is measured using Planar Laser Induced Fluorescence (PLIF), which provides a very accurate marker for the reaction zone location. The experimental results are compared to predictions by a one-dimensional simulation which incorporates full chemistry. Difficulties in performing detailed comparisons between one-dimensional simulations and finite-nozzle-diameter experiments are discussed in the context of validating chemical kinetics models. To further investigate the validity of these chemical kinetics models, global flame properties such as extinction strain-rates are also investigated.

  12. Predicting Examination Performance Using an Expanded Integrated Hierarchical Model of Test Emotions and Achievement Goals

    Science.gov (United States)

    Putwain, Dave; Deveney, Carolyn

    2009-01-01

    The aim of this study was to examine an expanded integrative hierarchical model of test emotions and achievement goal orientations in predicting the examination performance of undergraduate students. Achievement goals were theorised as mediating the relationship between test emotions and performance. 120 undergraduate students completed…

  13. Test Anxiety and Academic Performance among Undergraduates: The Moderating Role of Achievement Motivation.

    Science.gov (United States)

    Balogun, Anthony Gbenro; Balogun, Shyngle Kolawole; Onyencho, Chidi Victor

    2017-02-13

    This study investigated the moderating role of achievement motivation in the relationship between test anxiety and academic performance. Three hundred and ninety three participants (192 males and 201 females) selected from a public university in Ondo State, Nigeria using a purposive sampling technique, participated in the study. They responded to measures of test anxiety and achievement motivation. Three hypotheses were tested using moderated hierarchical multiple regression analysis. Results showed that test anxiety had a negative impact on academic performance (β = -.23; p academic performance (β = .38; p academic performance (β = .10; p < .01). These findings suggest that university management should design appropriate psycho-educational interventions that would enhance students' achievement motivation.

  14. The relation between teacher-set performance goals and students' mathematical achievement

    NARCIS (Netherlands)

    Ritzema, Evelien S.; Deunk, Marjolein I.; Bosker, Roel J.; van Kuijk, Mechteld F.

    2016-01-01

    The relation between teacher-set performance goals for 361 individual students and these students' mathematics achievement was investigated. High performance goals were found to strongly relate to student performance, with an effect size of d= 0.80. The performance goals were set by the teachers at

  15. The relation between teacher-set performance goals and students’ mathematical achievement

    NARCIS (Netherlands)

    Ritzema, E.S.; Deunk, M.I.; Bosker, R.J.; van Kuijk, M.F.

    2016-01-01

    The relation between teacher-set performance goals for 361 individual students and these students’ mathematics achievement was investigated. High performance goals were found to strongly relate to student performance, with an effect size of d = 0.80. The performance goals were set by the teachers at

  16. The relation between teacher-set performance goals and students’ mathematical achievement

    NARCIS (Netherlands)

    Ritzema, E.S.; Deunk, M.I.; Bosker, R.J.; van Kuijk, M.F.

    2016-01-01

    The relation between teacher-set performance goals for 361 individual students and these students’ mathematics achievement was investigated. High performance goals were found to strongly relate to student performance, with an effect size of d = 0.80. The performance goals were set by the teachers at

  17. The relation between teacher-set performance goals and students' mathematical achievement

    NARCIS (Netherlands)

    Ritzema, Evelien S.; Deunk, Marjolein I.; Bosker, Roel J.; van Kuijk, Mechteld F.

    2016-01-01

    The relation between teacher-set performance goals for 361 individual students and these students' mathematics achievement was investigated. High performance goals were found to strongly relate to student performance, with an effect size of d= 0.80. The performance goals were set by the teachers at

  18. On Stagnation points and streamline topology in vortex flows

    DEFF Research Database (Denmark)

    Aref, Hassan; Brøns, Morten

    1997-01-01

    The problem of locating stagnation points in the flow produced by a system of N interacting point vortices in two dimensions is considered. The general solution, which follows from an 1864 theorem by Siebeck, that the stagnation points are the foci of a certain plane curve of class N-1 that has a...

  19. Stagnation in mortality decline among elders in the Netherlands

    NARCIS (Netherlands)

    Janssen, F; Nusselder, WJ; Looman, CWN; Mackenbach, JP; Kunst, AE

    2003-01-01

    Purpose: This study assesses whether the stagnation of old-age (80+) mortality decline observed in The Netherlands in the 1980s continued in the 1990s and determines which factors contributed to this stagnation. Emphasis is on the role of smoking. Design and Methods: Poisson regression analysis with

  20. Orality disorders in melancholia: acedia as stagnation

    Directory of Open Access Journals (Sweden)

    Ana Cecília Magtaz

    2012-09-01

    Full Text Available In this article valuable contributions by Lasègue, Freud and Abraham are discussed, as they are all indispensible to the understanding of orality disorders in melancholia. Although none of the above authors used the exact term "orality disorders," their understandings of both hysteria and melancholia are important in the debate surrounding the clinical treatment of these difficulties. Sadness is a common denominator for the authors, but contributions on acedia, the "noonday demon" mentioned by Agamben, are also important. Acedia is defined as stagnation, a desperate lack of vigor when faced with a wearying and demanding situation. Those who suffer from chronic acedia feel great inertia and are unable to envision a future. They see their creativity wane away, especially due to the painful isolation caused by what might be called anguished sadness - a denial of sadness through manic action.

  1. Recirculation, stagnation and ventilation: The 2014 legionella episode

    Science.gov (United States)

    Russo, Ana; Soares, Pedro M. M.; Gouveia, Célia M.; Cardoso, Rita M.; Trigo, Ricardo M.

    2017-04-01

    period covering the 2014 event (7-25 November 2014). Hourly zonal (u) and meridional (v) wind components were retrieved from hindcast regional climate simulation covering the whole Iberian Peninsula (IP) with a spatial resolution of 9 km. This simulation was performed with the WRF model and for this study, the u and v components were extracted for a set of 12 points of the simulation grid around Lisbon. The preliminary results regarding the average daily critical transport indices for the 1989-2007 period clearly indicate that the airshed is prone to ventilation as these events have a dominant presence through most of the study period (72%), relatively to the occurrence of recirculation (10%) and stagnation (Civil & Environmental Engineering, S1:003.

  2. Achievement-related expectancies, academic self-concept, and mathematics performance of academically underprepared adolescent students.

    Science.gov (United States)

    House, J D

    1993-03-01

    The relationship between achievement-related expectancies, academic self-concept, and mathematics performance of 191 academically underprepared adolescent students was examined. After the effects of prior academic achievement were controlled for, a significant main effect for academic self-concept was found; as expected, students with higher academic self-concept earned significantly higher mathematics grades. In addition, after the effects of prior achievement were controlled for, female students were found to earn significantly higher mathematics grades than did male students. A significant three-way (Sex x Ethnic Group x Achievement-Related Expectancies) interaction was also noted. Unlike in several previous studies, no significant racial differences in mathematics performance were found. These students had a similar socioeconomic status (SES), and the effects of prior academic achievement were controlled for, suggesting that racial and gender differences in mathematics achievement may be partially explained by prior schooling and SES background, as posited by Reyes and Stanic (1988).

  3. Construct Validity of the Computerized Continuous Performance Test with Measures of Intelligence, Achievement, and Behavior.

    Science.gov (United States)

    Campbell, Janice Whitten; And Others

    1991-01-01

    Administered Continuous Performance Test (CPT), Wechsler Intelligence Scale for Children-Revised, Wide Range Achievement Test-Revised, Bender Visual-Motor Gestalt Test, and reading comprehension subtest of Peabody Individual Achievement Test to 54 school-aged children and adolescents referred for evaluation of learning disabilities. Parents…

  4. The association between physical activity, cognitive performance, and academic achievement in adolescents

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Kirschner, Paul A.

    2011-01-01

    Van Dijk, M. L., De Groot, R. H. M., Kirschner, P. A. (2011, 24 March). The association between physical activity, cognitive performance, and academic achievement in adolescents. Presentation at the ICO Introduction course, Utrecht, The Netherlands.

  5. The GOALS Study: The association between physical activity, cognitive performance, and academic achievement in adolescents

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Kirschner, Paul A.

    2011-01-01

    Van Dijk, M. L., De Groot, R. H. M., & Kirschner, P. A. (2011, 26 April). The GOALS Study: The association between physical activity, cognitive performance, and academic achievement in adolescents. Presentation at the Learning & Cognition meeting, Heerlen, The Netherlands.

  6. Neuropsychological and Academic Achievement Correlates of Abnormal WISC-R Verbal-Performance Discrepancies.

    Science.gov (United States)

    Lueger, Robert J.; And Others

    1985-01-01

    Examined neuropsychological and academic achievement correlates of statistically abnormal verbal-performance discrepancies on the Wechsler Intelligence Scale for Children (Revised). Results indicated that abnormal discrepancies reflect specific aphasia deficits rather than generalized neuropsychological dysfunction and that academic achievement…

  7. Performance-Approach and Performance-Avoidance Classroom Goals and the Adoption of Personal Achievement Goals

    Science.gov (United States)

    Schwinger, Malte; Stiensmeier-Pelster, Joachim

    2011-01-01

    Background: Students' perceptions of classroom goals influence their adoption of personal goals. To assess different forms of classroom goals, recent studies have favoured an overall measure of performance classroom goals, compared to a two-dimensional assessment of performance-approach and performance-avoidance classroom goals (PAVCG). Aims: This…

  8. Can achievement emotions be used to better understand motivation, learning, and performance in medical education?

    Science.gov (United States)

    Artino, Anthony R; Holmboe, Eric S; Durning, Steven J

    2012-01-01

    In this article, we consider an emergent theory of human emotion. The overarching purpose of the article is to introduce medical education researchers to the notion of achievement emotions and provide a brief overview of how this work can inform the theory, research, and practice of medical education. First, we define achievement emotions and describe one of the leading contemporary theories of achievement emotions, control-value theory (Pekrun R. 2006. The control-value theory of achievement emotions: Assumptions, corollaries, and implications for educational research and practice. Educ Psychol Rev 18:315-341.). Next, we distinguish between different types of achievement emotions, their proximal causes, and their consequences for motivation, learning, and performance, and we discuss several implications for educational practice. Finally, we end with a call for more research on achievement emotions in medical education to facilitate our understanding of emotions and their impact on important educational outcomes.

  9. A meta-analysis of self-reported achievement goals and nonself-report performance across three achievement domains (work, sports, and education.

    Directory of Open Access Journals (Sweden)

    Nico W Van Yperen

    Full Text Available During the past three decades, the achievement goal approach to achievement motivation has emerged as an influential area of research, and is dedicated to understanding the reasons behind the individual's drive to achieve competence and performance. However, the current literature on achievement goals is segmented rather than integrated. That is, citations across the three major and distinct achievement domains (work, education, and sports are more the exception than the rule and similarities and differences between findings for the different achievement domains have yet to be tested. The purpose of the present study was to examine the relationships between self-reported achievement goals and nonself-report performance through meta-analysis, and the moderating potential of achievement domain. Identifying achievement domain as moderator improves our understanding to which contexts we can (not generalize conclusions to, it helps to understand seemingly inconsistent findings, and opens avenues for future research on the underlying processes. Because the achievement goal (AG measure used in a study is partially confounded with achievement domain, we examined the moderating role of this variable as well. Our findings suggest that - overall - approach goals (either mastery or performance were associated positively with performance attainment, whereas avoidance goals (either mastery or performance were associated negatively with performance attainment. These relationships were moderated by achievement domain. For example, relative to the education or work domain, in the sports domain, we did not observe negative correlations between avoidance goals and performance. The absence of statistical moderation due to AG measure suggests that the observed moderation of achievement domain cannot be explained by the AG measure utilized. We suggest further steps to integrate the achievement goal literature, and accordingly, to broaden and deepen understanding of

  10. Prediction of intrinsic motivation and sports performance using 2 x 2 achievement goal framework.

    Science.gov (United States)

    Li, Chiung-Huang; Chi, Likang; Yeh, Suh-Ruu; Guo, Kwei-Bin; Ou, Cheng-Tsung; Kao, Chun-Chieh

    2011-04-01

    The purpose of this study was to examine the influence of 2 x 2 achievement goals on intrinsic motivation and performance in handball. Participants were 164 high school athletes. All completed the 2 x 2 Achievement Goals Questionnaire for Sport and the Intrinsic Motivation subscale of the Sport Motivation Scale; the coach for each team rated his athletes' overall sports performance. Using simultaneous-regression analyses, mastery-approach goals positively predicted both intrinsic motivation and performance in sports, whereas performance-avoidance goals negatively predicted sports performance. These results suggest that athletes who pursue task mastery and improvement of their competence perform well and enjoy their participation. In contrast, those who focus on avoiding normative incompetence perform poorly.

  11. The effect of adaptive performance support system on learning achievements of students

    NARCIS (Netherlands)

    Kommers, Piet; Stoyanov, Slavi; Mileva, Nevena; Martinez Mediano, Catalina

    2008-01-01

    The study compares the effectiveness of two performance support systems, adaptive and non-adaptive, on learning achievements of engineering students. In addition, the research design controls for a possible effect of learning style. The analysis reveals that students working with an adaptive perform

  12. How to achieve and prove performance improvement - 15 years of experience in German wastewater benchmarking.

    Science.gov (United States)

    Bertzbach, F; Franz, T; Möller, K

    2012-01-01

    This paper shows the results of performance improvement, which have been achieved in benchmarking projects in the wastewater industry in Germany over the last 15 years. A huge number of changes in operational practice and also in achieved annual savings can be shown, induced in particular by benchmarking at process level. Investigation of this question produces some general findings for the inclusion of performance improvement in a benchmarking project and for the communication of its results. Thus, we elaborate on the concept of benchmarking at both utility and process level, which is still a necessary distinction for the integration of performance improvement into our benchmarking approach. To achieve performance improvement via benchmarking it should be made quite clear that this outcome depends, on one hand, on a well conducted benchmarking programme and, on the other, on the individual situation within each participating utility.

  13. Boasts are a boost: achievement prime self-reactivity predicts subsequent academic performance.

    Science.gov (United States)

    Gramzow, Richard H; Johnson, Camille S; Willard, Greg

    2014-03-01

    The present research tests the hypothesis that self-reactivity following an achievement prime reflects the strength of achievement goals and is a predictor of future goal-relevant performance. In Studies 1-3, undergraduates reported their grade-point averages (GPAs) following either an achievement goal prime or a control prime. Academic exaggeration (higher self-reported than official GPA) was the indicator of self-reactivity to the prime. Study 1 involved a direct achievement goal prime, whereas Studies 2 and 3 involved indirect priming techniques. In all 3 experiments, greater academic exaggeration following the achievement goal prime (but not the control prime) predicted better academic performance a semester later (based on official records). Study 4 demonstrated that the magnitude of students' GPA goals mediated the association between academic exaggeration and subsequent performance (1 year later). The fact that self-reactivity to a single achievement goal prime in the lab predicted later performance in "real life" suggests that individual differences in reactivity to a specific prime can signal much broader motivational orientations related to the primed goal. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  14. The impact of the achievement motive on athletic performance in adolescent football players.

    Science.gov (United States)

    Zuber, Claudia; Conzelmann, Achim

    2014-01-01

    Researchers largely agree that there is a positive relationship between achievement motivation and athletic performance, which is why the achievement motive is viewed as a potential criterion for talent. However, the underlying mechanism behind this relationship remains unclear. In talent and performance models, main effect, mediator and moderator models have been suggested. A longitudinal study was carried out among 140 13-year-old football talents, using structural equation modelling to determine which model best explains how hope for success (HS) and fear of failure (FF), which are the aspects of the achievement motive, motor skills and abilities that affect performance. Over a period of half a year, HS can to some extent explain athletic performance, but this relationship is not mediated by the volume of training, sport-specific skills or abilities, nor is the achievement motive a moderating variable. Contrary to expectations, FF does not explain any part of performance. Aside from HS, however, motor abilities and in particular skills also predict a significant part of performance. The study confirms the widespread assumption that the development of athletic performance in football depends on multiple factors, and in particular that HS is worth watching in the medium term as a predictor of talent.

  15. Numerical Investigation of Nonisothermal Reversed Stagnation-point Flow

    OpenAIRE

    Chio, Chon Kit

    2013-01-01

    This thesis investigates the nature of the development of two-dimensional laminar nonisothermal flow of an incompressible fluid close to the reversed stagnation-point. Proudman and Johnson (1962) \\cite{proudman1962boundary} first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is not practice in neglecting the viscous terms within the total flow field. Viscous terms in this analysis are now included, and two-dimensional nonisothermal reversed stagnat...

  16. Student Achievement for Whom? High-Performing and Still "Playing the Game," the Meaning of School Achievement among High Achieving African American Students

    Science.gov (United States)

    Wiggan, Greg

    2014-01-01

    The preponderance of the research on African American students has generally focused on issues of school failure and underperformance. While the literature on high achieving Black students is sparse, very little is known about these students' school experiences and the meanings that they assign to achievement. Using student-based inquiry…

  17. Performance on large-scale science tests: Item attributes that may impact achievement scores

    Science.gov (United States)

    Gordon, Janet Victoria

    Significant differences in achievement among ethnic groups persist on the eighth-grade science Washington Assessment of Student Learning (WASL). The WASL measures academic performance in science using both scenario and stand-alone question types. Previous research suggests that presenting target items connected to an authentic context, like scenario question types, can increase science achievement scores especially in underrepresented groups and thus help to close the achievement gap. The purpose of this study was to identify significant differences in performance between gender and ethnic subgroups by question type on the 2005 eighth-grade science WASL. MANOVA and ANOVA were used to examine relationships between gender and ethnic subgroups as independent variables with achievement scores on scenario and stand-alone question types as dependent variables. MANOVA revealed no significant effects for gender, suggesting that the 2005 eighth-grade science WASL was gender neutral. However, there were significant effects for ethnicity. ANOVA revealed significant effects for ethnicity and ethnicity by gender interaction in both question types. Effect sizes were negligible for the ethnicity by gender interaction. Large effect sizes between ethnicities on scenario question types became moderate to small effect sizes on stand-alone question types. This indicates the score advantage the higher performing subgroups had over the lower performing subgroups was not as large on stand-alone question types compared to scenario question types. A further comparison examined performance on multiple-choice items only within both question types. Similar achievement patterns between ethnicities emerged; however, achievement patterns between genders changed in boys' favor. Scenario question types appeared to register differences between ethnic groups to a greater degree than stand-alone question types. These differences may be attributable to individual differences in cognition

  18. Direct measurement of the confinement time in a magnetically driven liner stagnation

    Science.gov (United States)

    Martin, Matthew

    2016-10-01

    We report on direct, radiographic measurement of the stagnation phase of a magnetically driven liner implosion. In experiments on the Z machine, a beryllium liner is filled with liquid deuterium and imploded to a minimum radius of 440 microns (radial convergence ratio of 7.7) over 300ns, achieving a density at stagnation of approximately 10 g/cc. The measured confinement time is 12.2 ns, compared to 14 ns from 1D simulations. Comparison of the evolution of the density profiles from the radiographs with the simulation shows a deviation in the reflected shock trajectory and the stagnation of the trailing mass. Additionally, the magneto-Raleigh-Taylor instability modifies the axial liner mass distribution, leading to enhanced compression with shorter confinement in the bubble region compared to the spikes, reducing the overall pressure-confinement time product by 29 percent as compared to the 1D simulation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. In collaboration with: Patrick Knapp & Daniel Dolan, Sandia National Labs.

  19. Performance Concern, Contingent Self-Worth, and Responses to Repeated Achievement Failure in Second Graders

    Science.gov (United States)

    Smiley, Patricia A.; Coulson, Sheri L.; Greene, Joelle K.; Bono, Katherine L.

    2010-01-01

    Individual differences in emotion, cognitions, and task choice following achievement failure are found among four- to seven-year-olds. However, neither performance deterioration during failure nor generalization after failure--aspects of the helpless pattern in 10-year-olds--have been reliably demonstrated in this age group. In the present study,…

  20. Making Employee Recognition a Tool for Achieving Improved Performance: Implication for Ghanaian Universities

    Science.gov (United States)

    Amoatemaa, Abena Serwaa; Kyeremeh, Dorcas Darkoah

    2016-01-01

    Many organisations are increasingly making use of employee recognition to motivate employees to achieve high performance and productivity. Research has shown that effective recognition occurs in organisations that have strong supportive culture, understand the psychology of praising employees for their good work, and apply the principles of…

  1. Four Language Skills Performance, Academic Achievement, and Learning Strategy Use in Preservice Teacher Training Programs

    Science.gov (United States)

    Shawer, Saad Fathy

    2016-01-01

    This article examines the differences in language learning strategies (LLS) use between preservice teachers of English as a foreign language (EFL) and Arabic as a second language (ASL). It also examines the relationship between LLS use and language performance (academic achievement and four language skills) among ASL students. The study made use…

  2. On the achievable performance using variable geometry active secondary suspension systems in commercial vehicles

    NARCIS (Netherlands)

    Evers, W.J.; Besselink, I.G.M.; Teerhuis, A.P.; Nijmeijer, H.

    2011-01-01

    There is a need to further improve driver comfort in commercial vehicles. The variable geometry active suspension offers an interesting option to achieve this in an energy efficient way. However, the optimal control strategy and the overal performance potential remains unclear. The aim of this paper

  3. Four Language Skills Performance, Academic Achievement, and Learning Strategy Use in Preservice Teacher Training Programs

    Science.gov (United States)

    Shawer, Saad Fathy

    2016-01-01

    This article examines the differences in language learning strategies (LLS) use between preservice teachers of English as a foreign language (EFL) and Arabic as a second language (ASL). It also examines the relationship between LLS use and language performance (academic achievement and four language skills) among ASL students. The study made use…

  4. Gender, Geographic Locations, Achievement Goals and Academic Performance of Secondary School Students from Borno State, Nigeria

    Science.gov (United States)

    Musa, Alice K.J.

    2013-01-01

    The paper examined gender, geography location, achievement goals and academic performance of senior secondary school students in Borno State, Nigeria. The sample consists of 827 students from 18 public boarding secondary schools across South and North of Borno State: 414 (50.1 per cent) males and 413 (49.9 per cent) are females; 414 (50.1 per…

  5. Project REACH. Regional Education to Achieve with Company Help. Performance Report.

    Science.gov (United States)

    Parkway School District, Chesterfield, MO.

    Project REACH (Regional Education to Achieve with Company) was a regional workplace literacy (WL) program designed to increase the levels of literacy, job performance/satisfaction/retention, productivity, and self-esteem of the work force of six businesses in the Saint Louis area and to foster the development of business-education partnerships for…

  6. Achievement Motivation: Conceptions of Ability, Subjective Experience, Task Choice, and Performance.

    Science.gov (United States)

    Nicholls, John G.

    1984-01-01

    Achievement behavior is defined as behavior directed at demonstrating high ability. Ability is conceived as relative to one's own past performance, or relative to that of others. Conditions under which these conceptions of ability function as individual's goals and the nature of subjective experience in each case are specified. (Author/BW)

  7. Immigrant Children's Educational Achievement in Western Countries: Origin, Destination, and Community Effects on Mathematical Performance

    Science.gov (United States)

    Levels, Mark; Dronkers, Jaap; Kraaykamp, Gerbert

    2008-01-01

    This article explores the extent to which macro-level characteristics of destination countries, origin countries, and immigrant communities help explain differences in immigrant children's educational achievement. Using data from the 2003 PISA survey, we analyze the mathematical performance of 7,403 pupils from 35 different origin countries in 13…

  8. A meta-analysis of the impact of situationally induced achievement goals on task performance

    NARCIS (Netherlands)

    Van Yperen, Nico W.; Blaga, Monica; Postmes, Thomas

    2015-01-01

    The purpose of this research was to meta-analyze studies which experimentally induced an achieve- ment goal state to examine its causal effect on the individual’s performance at the task at hand, and to investigate the moderator effects of feedback anticipation and time pressure. The data set compri

  9. The effect of adaptive performance support system on learning achievements of students

    NARCIS (Netherlands)

    Kommers, Petrus A.M.; Stoyanov, S.; Stoyanov, Slavi; Mileva, Nevena; Martinez Mediano, Catalina

    2008-01-01

    The study compares the effectiveness of two performance support systems, adaptive and non-adaptive, on learning achievements of engineering students. In addition, the research design controls for a possible effect of learning style. The analysis reveals that students working with an adaptive

  10. On the achievable performance using variable geometry active secondary suspension systems in commercial vehicles

    NARCIS (Netherlands)

    Evers, W.J.; Besselink, I.G.M.; Teerhuis, A.P.; Nijmeijer, H.

    2011-01-01

    There is a need to further improve driver comfort in commercial vehicles. The variable geometry active suspension offers an interesting option to achieve this in an energy efficient way. However, the optimal control strategy and the overal performance potential remains unclear. The aim of this paper

  11. Using absolute x-ray spectral measurements to infer stagnation conditions in ICF implosions

    Science.gov (United States)

    Patel, Pravesh; Benedetti, L. R.; Cerjan, C.; Clark, D. S.; Hurricane, O. A.; Izumi, N.; Jarrott, L. C.; Khan, S.; Kritcher, A. L.; Ma, T.; Macphee, A. G.; Landen, O.; Spears, B. K.; Springer, P. T.

    2016-10-01

    Measurements of the continuum x-ray spectrum emitted from the hot-spot of an ICF implosion can be used to infer a number thermodynamic properties at stagnation including temperature, pressure, and hot-spot mix. In deuterium-tritium (DT) layered implosion experiments on the National Ignition Facility (NIF) we field a number of x-ray diagnostics that provide spatial, temporal, and spectrally-resolved measurements of the radiated x-ray emission. We report on analysis of these measurements using a 1-D hot-spot model to infer thermodynamic properties at stagnation. We compare these to similar properties that can be derived from DT fusion neutron measurements. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Modeling and simulation of axisymmetric stagnation flames

    Science.gov (United States)

    Sone, Kazuo

    Laminar flame modeling is an important element in turbulent combustion research. The accuracy of a turbulent combustion model is highly dependent upon our understanding of laminar flames and their behavior in many situations. How much we understand combustion can only be measured by how well the model describes and predicts combustion phenomena. One of the most commonly used methane combustion models is GRI-Mech 3.0. However, how well the model describes the reacting flow phenomena is still uncertain even after many attempts to validate the model or quantify uncertainties. In the present study, the behavior of laminar flames under different aerodynamic and thermodynamic conditions is studied numerically in a stagnation-flow configuration. In order to make such a numerical study possible, the spectral element method is reformulated to accommodate the large density variations in methane reacting flows. In addition, a new axisymmetric basis function set for the spectral element method that satisfies the correct behavior near the axis is developed, and efficient integration techniques are developed to accurately model axisymmetric reacting flow within a reasonable amount of computational time. The numerical method is implemented using an object-oriented programming technique, and the resulting computer program is verified with several different verification methods. The present study then shows variances with the commonly used GRI-Mech 3.0 chemical kinetics model through a direct simulation of laboratory flames that allows direct comparison to experimental data. It is shown that the methane combustion model based on GRI-Mech 3.0 works well for methane-air mixtures near stoichiometry. However, GRI-Mech 3.0 leads to an overprediction of laminar flame speed for lean mixtures and an underprediction for rich mixtures. This result is slightly different from conclusion drawn in previous work, in which experimental data are compared with a one-dimensional numerical solutions

  13. The C-2000 program : achieving high performance through better technologies and changes in the design process

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-09-01

    In 1993, CANMET Energy Technology Centre of Natural Resources Canada launched a demonstration program for high-performance buildings. The focus of the C-2000 Program for Advanced Commercial Buildings was on energy and environmental performance, but it also included a variety of other parameters. Of the 13 buildings that have been designed, some have been built while others are approaching the construction phase. The Canadian Model National Energy Code for Buildings (MNECB) is the standard used as a performance benchmark. The demonstration program has shown that the likelihood of high performance depends on close teamwork by all members of a building design team with the augmentation of a normal design team with an energy engineer, an environmental specialist and a cost consultant. Other factors which help achiever high performance are the use of clear and comprehensive technical guidelines and the development of short written performance strategies. The commissioning of all major systems during the construction phase also help ensure that the systems are properly installed and perform to design levels. The completed projects have confirmed that a 35 to 50 per cent improvement in energy performance levels can be achieved with only modest increases in design budgets. 7 refs., 7 figs.

  14. ACHIEVING MATURITY (AND MEASURING PERFORMANCE THROUGH MODEL-BASED PROCESS IMPROVEMENT

    Directory of Open Access Journals (Sweden)

    Jose Marcelo Almeida Prado Cestari

    2013-08-01

    Full Text Available This paper presents the approach adopted by a software development unit in order to achieve the maturity level 3 of CMMI-DEV and therefore obtaining better performance. Through historical research and secondary data analysis of the organization, the paper intends to answer the following research question: "Could the adoption of maturity/best practices models bring better performance results to small and medium organizations?" Data and analysis conducted show that, besides the creation of indicator’s based management, there are some quantitative performance improvements in indicators such as: Schedule Deviation Rate, Effort Deviation Rate, Percent Late Delivery, Productivity Deviation and Internal Rework Rate

  15. The Best Achievable ℋ2 Tracking Performances for SIMO Feedback Control Systems

    Directory of Open Access Journals (Sweden)

    Shinji Hara

    2007-01-01

    Full Text Available This paper is concerned with the inherent ℋ2 tracking performance limitation of single-input and multiple-output (SIMO linear time-invariant (LTI feedback control systems. The performance is measured by the tracking error between a step reference input and the plant output with additional penalty on control input. We employ the plant augmentation strategy, which enables us to derive analytical closed-form expressions of the best achievable performance not only for discrete-time system, but also for continuous-time system by exploiting the delta domain version of the expressions.

  16. A physical education trial improves adolescents' cognitive performance and academic achievement: the EDUFIT study.

    Science.gov (United States)

    Ardoy, D N; Fernández-Rodríguez, J M; Jiménez-Pavón, D; Castillo, R; Ruiz, J R; Ortega, F B

    2014-02-01

    To analyze the effects of an intervention focused on increasing the time and intensity of Physical Education (PE), on adolescents' cognitive performance and academic achievement. A 4-month group-randomized controlled trial was conducted in 67 adolescents from South-East Spain, 2007. Three classes were randomly allocated into control group (CG), experimental group 1 (EG1) and experimental group 2 (EG2). CG received usual PE (two sessions/week), EG1 received four PE sessions/week and EG2 received four PE sessions/week of high intensity. Cognitive performance (non-verbal and verbal ability, abstract reasoning, spatial ability, verbal reasoning and numerical ability) was assessed by the Spanish Overall and Factorial Intelligence Test, and academic achievement by school grades. All the cognitive performance variables, except verbal reasoning, increased more in EG2 than in CG (all P performance and academic achievement. This study contributes to the current knowledge by suggesting that the intensity of PE sessions might play a role in the positive effect of physical activity on cognition and academic success. Future studies involving larger sample sizes should confirm or contrast these preliminary findings.

  17. Daily online testing in large classes: boosting college performance while reducing achievement gaps.

    Science.gov (United States)

    Pennebaker, James W; Gosling, Samuel D; Ferrell, Jason D

    2013-01-01

    An in-class computer-based system, that included daily online testing, was introduced to two large university classes. We examined subsequent improvements in academic performance and reductions in the achievement gaps between lower- and upper-middle class students in academic performance. Students (N = 901) brought laptop computers to classes and took daily quizzes that provided immediate and personalized feedback. Student performance was compared with the same data for traditional classes taught previously by the same instructors (N = 935). Exam performance was approximately half a letter grade above previous semesters, based on comparisons of identical questions asked from earlier years. Students in the experimental classes performed better in other classes, both in the semester they took the course and in subsequent semester classes. The new system resulted in a 50% reduction in the achievement gap as measured by grades among students of different social classes. These findings suggest that frequent consequential quizzing should be used routinely in large lecture courses to improve performance in class and in other concurrent and subsequent courses.

  18. Behavior of a solar collector loop during stagnation

    DEFF Research Database (Denmark)

    Chen, Ziqian; Dragsted, Janne; Furbo, Simon

    2015-01-01

    A mathematical model simulating the emptying behavior of a pressurized solar collector loop with solar collectors with a good emptying behavior is developed and validated with measured data. The calculated results are in good agreement with the measured results. The developed simulation model...... is therefore suitable to determine the behavior of a solar collector loop during stagnation. A volume ratio R, which is the ratio of the volume of the vapour in the upper pipes of the solar collector loop during stagnation and the fluid content of solar collectors, is introduced to determine the mass...... of the collector fluid pushed into the expansion vessel during stagnation, Min. A correlation function for the mass Min and the volume ratio R for solar collector loops is obtained. The function can be used to determine a suitable size of expansion vessels for solar collector loops....

  19. Theoretical study on a solar collector loop during stagnation

    DEFF Research Database (Denmark)

    Chen, Ziqian; Dragsted, Janne; Furbo, Simon;

    2010-01-01

    A mathematical model simulating the stagnation behavior of a pressurized solar collector loop with solar collectors with a good emptying behavior is developed. Based on the pre-pressure of the expansion vessel, the system filling pressure of the solar collector loop and the design of the solar...... collector loop, the mass of the fluid flowing into the pressurized expansion vessel and the pressures at the top part and at the bottom part of the solar collector loop during stagnation for the solar collector loop are calculated. The theoretically calculated results are compared with experimental results....... There is a good agreement between calculations and measurements. The developed simulation model is therefore suitable to determine the behavior of solar collector loops during stagnation....

  20. Theoretical study on a solar collector loop during stagnation

    DEFF Research Database (Denmark)

    Chen, Ziqian; Dragsted, Janne; Furbo, Simon;

    A mathematical model simulating the stagnation behavior of a pressurized solar collector loop with solar collectors with a good emptying behavior is developed. Based on the pre-pressure of the expansion vessel, the system filling pressure of the solar collector loop and the design of the solar...... collector loop, the mass of the fluid flowing into the pressurized expansion vessel and the pressures at the top part and at the bottom part of the solar collector loop during stagnation for the solar collector loop are calculated. The theoretically calculated results are compared with experimental results....... There is a good agreement between calculations and measurements. The developed simulation model is therefore suitable to determine the behavior of solar collector loops during stagnation....

  1. Relationship of Mathematics Olympiad Performance of Gifted Students with IQ and Mathematics Achievement

    Directory of Open Access Journals (Sweden)

    Ali İhsan BORAN

    2015-04-01

    Full Text Available The purpose of this study is to investigate relationship of mathematics Olympiad (analysis-algebra and geometry scores of gifted students with IQ scores (verbal, performance and general and mathematics achievement scores of the gifted students. Study group of the study included 64 gifted students (27 girls and 37 boys who took courses from one Science and Art Center. Data of study involved scores of the participants on mathematics Olympiad exam, WISC-R test and school mathematics achievement. For analysis of the data Pearson correlation analysis, Spearman correlation analysis, independent groups’ t-test and Mann Whitney U test were utilized. The findings showed that there was no significant relationship between the Olympiad scores on analysis-algebra and geometry and IQ scores (general, performance and verbal. But the Olympiad scores on analysis-algebra and geometry factors were significantly related to school mathematics achievement. Comparing IQ scores of highest and lowest scorer groups on the Olympiad scores showed that there were no significant differences between IQ scores (general, performance and verbal of the groups. However school mathematics scores of the participants significantly differed in terms of groups determined based on analysis-algebra and geometry scores.

  2. Achieving High Performance Distributed System: Using Grid, Cluster and Cloud Computing

    Directory of Open Access Journals (Sweden)

    Sunil Kr Singh

    2015-02-01

    Full Text Available To increase the efficiency of any task, we require a system that would provide high performance along with flexibilities and cost efficiencies for user. Distributed computing, as we are all aware, has become very popular over the past decade. Distributed computing has three major types, namely, cluster, grid and cloud. In order to develop a high performance distributed system, we need to utilize all the above mentioned three types of computing. In this paper, we shall first have an introduction of all the three types of distributed computing. Subsequently examining them we shall explore trends in computing and green sustainable computing to enhance the performance of a distributed system. Finally presenting the future scope, we conclude the paper suggesting a path to achieve a Green high performance distributed system using cluster, grid and cloud computing

  3. Unsteady Reversed Stagnation-Point Flow over a Flat Plate

    OpenAIRE

    Sin, Vai Kuong; Chio, Chon Kit

    2012-01-01

    This paper investigates the nature of the development of two-dimensional laminar flow of an incompressible fluid at the reversed stagnation-point. ". In this study, we revisit the problem of reversed stagnation-point flow over a flat plate. Proudman and Johnson (1962) first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is no true in neglecting the viscous terms within the total flow field. In particular it is pointed out that for a plate impulsivel...

  4. Magnetohydrodynamics stagnation point flow towards a stretching vertical sheet

    Science.gov (United States)

    Ishak, A.; Nazar, R.; Pop, I.

    2006-03-01

    The analysis of steady two-dimensional stagnation point flow of an incompressible viscous and electrically conducting fluid, subject to a transverse uniform magnetic field, over a vertical stretching sheet is investigated when the sheet is stretched in its own plane with a velocity and a temperature proportional to the distance from the stagnation point. It is shown that the basic partial differential equations reduce to similarity equations. This is followed by a direct numerical solution of the resulting boundary value problem using a very efficient finite-difference method. Discussions are made to trace among them the physically realistic solution. Tables 5, Figs 13, Refs 17.

  5. Numerical Investigation of Nonisothermal Reversed Stagnation-point Flow

    CERN Document Server

    Kit, Chio Chon

    2013-01-01

    This thesis investigates the nature of the development of two-dimensional laminar nonisothermal flow of an incompressible fluid close to the reversed stagnation-point. Proudman and Johnson (1962) \\cite{proudman1962boundary} first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is not practice in neglecting the viscous terms within the total flow field. Viscous terms in this analysis are now included, and two-dimensional nonisothermal reversed stagnation-point flow is investigated by solving the Navier-Stokes equations coupled to energy equation.

  6. Unsteady Reversed Stagnation-Point Flow over a Flat Plate

    CERN Document Server

    Sin, Vai Kuong

    2013-01-01

    This paper investigates the nature of the development of two-dimensional laminar flow of an incompressible fluid at the reversed stagnation-point. ". In this study, we revisit the problem of reversed stagnation-point flow over a flat plate. Proudman and Johnson (1962) first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is no true in neglecting the viscous terms within the total flow field. In particular it is pointed out that for a plate impulsively accelerated from rest to a constant velocity V0 that a similarity solution to the self-similar ODE is obtained which is noteworthy completely analytical.

  7. Understanding the stagnation and burn of implosions on NIF

    Science.gov (United States)

    Kilkenny, J. D.; Caggiano, J. A.; Hatarik, R.; Knauer, J. P.; Sayre, D. B.; Spears, B. K.; Weber, S. V.; Yeamans, C. B.; Cerjan, C. J.; Divol, L.; Eckart, M. J.; Glebov, V. Yu; Herrmann, H. W.; Le Pape, S.; Munro, D. H.; Grim, G. P.; Jones, O. S.; Berzak-Hopkins, L.; Gatu-Johnson, M.; Mackinnon, A. J.; Meezan, N. B.; Casey, D. T.; Frenje, J. A.; Mcnaney, J. M.; Petrasso, R.; Rinderknecht, H.; Stoeffl, W.; Zylstra, A. B.

    2016-03-01

    An improved the set of nuclear diagnostics on NIF measures the properties of the stagnation plasma of implosions, including the drift velocity, areal density (ρr) anisotropy and carbon ρr of the compressed core. Two types of deuterium-tritium (DT) gas filled targets are imploded by shaped x-ray pulses, producing stagnated and burning DT cores of radial convergence (Cr) ∼ 5 or ∼20. Comparison with two-dimensional modeling with inner and outer surface mix shows good agreement with nuclear measurements.

  8. The Problem: Low-Achieving Districts and Low-Performing Boards

    Directory of Open Access Journals (Sweden)

    David E. Lee

    2014-10-01

    Full Text Available Effective school districts maintain superintendent and school board collegiality which can foster success and connectedness among members. Delagardelle and Alsbury (2008 found that superintendents and board members are not consistent in their perceptions about the work the board does, and Glass (2007 found that states do not require boards to undergo evaluation for effectiveness. In the current study, 115 board meetings were observed using the School Board Video Project (SBVP survey, which was created in 2012 by researchers to uncover school board meetings’ effectiveness. MANOVA, Univariate ANOVA, and Pearson Chi-Square test results revealed significant differences between low-, medium-, and high-performing districts’ school board meetings. Evidence indicated that low-performing districts’ board meetings were: less orderly; had less time spent on student achievement; lacked respectful and attentive engagement across speakers; had board meeting members who seemed to advance their own agenda; had less effective working relationships among the governance team; had fewer board members who relied on the superintendent for advice and input; had one member, other than the board president, stand out for taking excessive time during meetings; and did not focus on policy items as much as high- and medium-performing school districts. The research concluded that more school board members from low-performing districts needed training to improve their effectiveness. Furthermore, highly refined and target-enhanced school board training programs might lead to lasting governance success and more effective teaming that could improve district, and ultimately, student achievement.

  9. Social jetlag, academic achievement and cognitive performance: Understanding gender/sex differences.

    Science.gov (United States)

    Díaz-Morales, Juan F; Escribano, Cristina

    2015-01-01

    Adolescents in high school suffer from circadian misalignment, undersleeping on weekdays and oversleeping on weekends. Since high schools usually impose early schedules, adolescents suffer from permanent social jetlag (SJL) and thus are a suitable population to study the effects of SJL on both academic and cognitive performance. In this study, 796 adolescents aged 12-16 years reported information about their sleep habits, morningness-eveningness (M-E), cognitive abilities and grade point average (GPA). Time in bed on both weekdays and weekends was not related to cognitive abilities, and only time in bed on weekdays was related to academic achievement. SJL was negatively related to academic achievement, cognitive abilities (except for vocabulary and verbal fluency abilities) and general cognitive ability (g), whereas M-E was slightly positively related to academic achievement and marginally negatively related to inductive reasoning. Results separated by sex/gender indicated that SJL may be more detrimental to girls' performance, as it was negatively related to a greater number of cognitive abilities and GPA.

  10. On stagnation points and streamline topology in vortex flows

    DEFF Research Database (Denmark)

    Aref, Hassan; Brøns, Morten

    1998-01-01

    of the stagnation point in a flow produced by three vortices with sum of strengths zero is found. Using topological arguments the distinct streamline patterns for flow about three vortices are also determined. Partial results are given for two special sets of vortex strengths on the changes between these patterns...

  11. Stability of stagnation via an expanding accretion shock wave

    CERN Document Server

    Velikovich, A L; Taylor, B D; Giuliani, J L; Zalesak, S T; Iwamoto, Y

    2016-01-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Y. Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [H. Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); M. Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic...

  12. Stability of stagnation via an expanding accretion shock wave

    Science.gov (United States)

    Velikovich, A. L.; Murakami, M.; Taylor, B. D.; Giuliani, J. L.; Zalesak, S. T.; Iwamoto, Y.

    2016-05-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  13. Occurrence and persistence of future atmospheric stagnation events

    Science.gov (United States)

    Horton, Daniel E.; Skinner, Christopher B.; Singh, Deepti; Diffenbaugh, Noah S.

    2014-08-01

    Poor air quality causes an estimated 2.6-4.4 million premature deaths per year. Hazardous conditions form when meteorological components allow the accumulation of pollutants in the near-surface atmosphere. Global-warming-driven changes to atmospheric circulation and the hydrological cycle are expected to alter the meteorological components that control pollutant build-up and dispersal, but the magnitude, direction, geographic footprint and public health impact of this alteration remain unclear. We used an air stagnation index and an ensemble of bias-corrected climate model simulations to quantify the response of stagnation occurrence and persistence to global warming. Our analysis projects increases in stagnation occurrence that cover 55% of the current global population, with areas of increase affecting ten times more people than areas of decrease. By the late twenty-first century, robust increases of up to 40 days per year are projected throughout the majority of the tropics and subtropics, as well as within isolated mid-latitude regions. Potential impacts over India, Mexico and the western US are particularly acute owing to the intersection of large populations and increases in the persistence of stagnation events, including those of extreme duration. These results indicate that anthropogenic climate change is likely to alter the level of pollutant management required to meet future air quality targets.

  14. Estimation of fluid flow fields and their stagnation points

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    Given a temporal sequence of images of fluids we will use local polynomials to regularise obser-vations of normal flows into smooth flow fields. This technique furthermore allows us to give a qualitative local description of the flow field and to estimate the position of stagnation points...

  15. Generativity-Stagnation: Development of a Status Model.

    Science.gov (United States)

    Bradley, Cheryl L.

    1997-01-01

    Reviews theoretical and empirical developments in Erik Erikson's construct of generativity-stagnation. Presents a five-category model describing styles of resolving the issue using combinations of level of involvement or active concern for the growth of self and others; and level of inclusivity or scope of caregiving concern. Discusses model in…

  16. Modeling ion interpenetration, stagnation, and thermalization in colliding plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jones, M.E.; Winske, D.; Goldman, S.R.; Kopp, R.A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rogatchev, V.G.; Belkov, S.A.; Gasparyan, P.D.; Dolgoleva, G.V.; Zhidkov, N.V.; Ivanov, N.V.; Kochubej, Y.K.; Nasyrov, G.F.; Pavlovskii, V.A.; Smirnov, V.V.; Romanov, Y.A. [All Russian Scientific Research Institute of Experimental Physics, Sarov (Arzamas 16), Nizhniy Novgorod Region, 607200 (Russia)

    1996-03-01

    Ion interpenetration, stagnation, and energization processes are studied in colliding laser-produced plasma configurations relevant to Trident [R. G. Watt, Rev. Sci. Instrum. {bold 64}, 1770 (1993)] experiments using four different numerical methods: one-dimensional Monte Carlo and Lagrangian multifluid codes, and one- and two-dimensional hybrid (particle ions, fluid electrons) and single-fluid Lagrangian codes. Results from the four methodologies are compared for plasmas generated with gold and deuterated polyethylene (CD{sub 2}) targets. Overall, the various codes give similar results concerning the initial expansion of the plasmas and their collisional interaction, the degree of stagnation, stagnation time, and amount of ion thermalization for gold targets, while multispecies techniques indicate a much softer stagnation for CD{sub 2} plasmas than the single-fluid model. Variations in the results of the calculations due to somewhat different initializations and parameters, as well as to different physics in the codes, are discussed. {copyright} {ital 1996 American Institute of Physics.}

  17. The stagnation point von K\\'arm\\'an coefficient

    CERN Document Server

    Dallas, Vassilios; Hewitt, Geoffrey F

    2009-01-01

    On the basis of various DNS of turbulent channel flows the following picture is proposed. (i) At a height y from the y = 0 wall, the Taylor microscale \\lambda is proportional to the average distance l_s between stagnation points of the fluctuating velocity field, i.e. \\lambda(y) = B_1 l_s(y) with B_1 constant, for \\delta_\

  18. Stability of stagnation via an expanding accretion shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Velikovich, A. L.; Giuliani, J. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Taylor, B. D. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC 20375 (United States); Zalesak, S. T. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States); Iwamoto, Y. [Ehime University, Matsuyama, Ehime Pref. 790-8577 (Japan)

    2016-05-15

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  19. INFORMATION SYSTEM DESIGN OF PERFORMANCE ACHIEVEMENTS MONITORING IN THE UNIVERSITY: A CASE STUDY IN BINUS UNIVERSITY

    Directory of Open Access Journals (Sweden)

    Irma Irawati Ibrahim

    2012-05-01

    Full Text Available Dashboard is a computer interface that displays a variety of charts, graphs, tables, which are selected reports from various data that are considered important to display rapidly, with an attractive appearance, dynamic, and relevant so that it can immediately be seen quickly to analyze a condition. Dashboard information system is widely used in various companies as a support system for decision-making where Dashboard usually displays data business trends of the company or the achievement of KPI (Key Performance Indicator of a company. The method used is descriptive analysis by means of collecting information that areimportant for universities to be considered asthe Key Success Factors (KSF of the university, and then, the design of the dashboard is made in accordance with these important factors.The result of this study is a grand design of information systems for the university performance monitoring, starting from the reception of students, faculty performance, student academic achievement, effectiveness and efficiency of services, including graduates. It is expected that by the time the system has been fully implemented, the university can take action quickly and accurately with respect to the required conditions.Keywords: Information System Dashboard; Dashboard; Academic Dashboard; University Dashboard

  20. No association between cognitive achievements, academic performance and serum cholesterol concentrations among school-aged children.

    Science.gov (United States)

    Perry, Lewis A; Stigger, Cagney B; Ainsworth, Barbara E; Zhang, Jian

    2009-08-01

    The uncertainty of the role of serum cholesterol in neurodevelopment of children has largely hampered the implementation of the fat recommendation to children in the general population. We explored whether serum cholesterol concentrations are associated with cognitive achievements, academic performance in school-aged children and adolescents at the population level. In the Third National Health and Nutrition Survey, blood specimens were collected from 4248 6-16-year-old children and adolescents to assess three serum cholesterol measures, e.g. total serum cholesterol, high density lipoprotein (HDL) cholesterol and non-high density lipoprotein cholesterol. Cognitive achievements and academic performance were measured on standard tests of arithmetic skills, reading skills, non-verbal reasoning and short-term memory. No significant difference in measures of cognitive and academic performance was observed between children and adolescents stratified by the levels of serum total, HDL, and non-HDL cholesterol. Our results suggest that differences within the normal range of serum lipids at a population level are not associated with intelligence and cognition developmental outcomes of children and adolescents.

  1. The predictive value of pre-recruitment achievement on resident performance in anesthesiology.

    Science.gov (United States)

    Chen, Fei; Arora, Harendra; Martinelli, Susan M; Teeter, Emily; Mayer, David; Zvara, David A; Passannante, Anthony; Smith, Kathleen A

    2017-06-01

    Selecting candidates for residency positions is challenging and there is little research on the correlation between commonly used selection criteria and subsequent performance in anesthesiology. This study examined the association between the selection measures and post-recruitment performance in residency. Retrospective review of archival data. Anesthesiology residency program at a large academic anesthesiology department. Residents who were matched to the anesthesiology program over 9years (graduation classes of 2006 to 2014). None. The pre-recruitment achievements included a comprehensive list of measures obtained from residents' application portfolios in conjunction with interview performance. The post-recruitment examination outcomes consisted of the in-training examination (ITE) scores in the three clinical anesthesia (CA) years and first-attempt success on the written board certification examination administered by the American Board of Anesthesiology (ABA). Scholarly output during residency was measured by publication record. Clinical performance at the conclusion of residency was independently rated by three faculty members. Bivariate analysis and regression models were conducted to examine association between predictors and outcomes. High United States Medical Licensing Examination (USMLE) scores, class rank in medical school and interview performance were predictive of high examination scores in residency and good clinical performance. Class rank appeared to be the best predictor of scholarly publication and pursuing an academic career beyond residency. Comparative performance with classmates (i.e., class rank) in medical school appeared to be an effective predictor of overall performance in residency, which warrants more attention in future study. Although interview performance is subject to recruitment team members' interpretation, it is an important measure to include in recruitment decisions. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Staffing of Time-Varying Queues to Achieve Time-Stable Performance

    OpenAIRE

    Zohar Feldman; Avishai Mandelbaum; William A. Massey; Ward Whitt

    2008-01-01

    This paper develops methods to determine appropriate staffing levels in call centers and other many-server queueing systems with time-varying arrival rates. The goal is to achieve targeted time-stable performance, even in the presence of significant time variation in the arrival rates. The main contribution is a flexible simulation-based iterative-staffing algorithm (ISA) for the M t /G/s t + G model--with nonhomogeneous Poisson arrival process (the M t ) and customer abandonment (the + G). F...

  3. Performance Evaluation of Methods for Estimating Achievable Throughput on Cellular Connections

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Møller; Højholt, Nikolaj Bove; Madsen, Tatiana Kozlova

    2015-01-01

    The continuous increase in always connected devices and the advance in capabilities of networks and services offered via the network is evident. The target group of most of these devices and services is users, so how users perceive the network performance is of great importance. Estimating...... achievable throughput (AT) is the main focus of this paper, which can be expressed as the data rate that users experience. We establish the Bulk Transfer Capacity (BTC) method as the ground truth of the AT. We choose to evaluate the Trains of Packet-Pair (TOPP) method as an alternative to BTC in estimating...

  4. NUMBER OF TRIALS NECESSARY TO ACHIEVE PERFORMANCE STABILITY OF SELECTED GROUND REACTION FORCE VARIABLES DURING LANDING

    Directory of Open Access Journals (Sweden)

    C. Roger James

    2007-03-01

    Full Text Available The objectives were to determine the number of trials necessary to achieve performance stability of selected ground reaction force (GRF variables during landing and to compare two methods of determining stability. Ten subjects divided into two groups each completed a minimum of 20 drop or step-off landings from 0.60 or 0.61 m onto a force platform (1000 Hz. Five vertical GRF variables (first and second peaks, average loading rates to these peaks, and impulse were quantified during the initial 100 ms post-contact period. Test-retest reliability (stability was determined using two methods: (1 intra-class correlation coefficient (ICC analysis, and (2 sequential averaging analysis. Results of the ICC analysis indicated that an average of four trials (mean 3.8 ± 2.7 Group 1; 3.6 ± 1.7 Group 2 were necessary to achieve maximum ICC values. Maximum ICC values ranged from 0.55 to 0.99 and all were significantly (p < 0. 05 different from zero. Results of the sequential averaging analysis revealed that an average of 12 trials (mean 11.7 ± 3.1 Group 1; 11.5 ± 4.5 Group 2 were necessary to achieve performance stability using criteria previously reported in the literature. Using 10 reference trials, the sequential averaging technique required standard deviation criterion values of 0.60 and 0.49 for Groups 1 and 2, respectively, in order to approximate the ICC results. The results of the study suggest that the ICC might be a less conservative, but more objective method for determining stability, especially when compared to previous applications of the sequential averaging technique. Moreover, criteria for implementing the sequential averaging technique can be adjusted so that results closely approximate the results from ICC. In conclusion, subjects in landing experiments should perform a minimum of four and possibly as many as eight trials to achieve performance stability of selected GRF variables. Researchers should use this information to plan future

  5. Neuroanatomical correlates of performance in a state-wide test of math achievement.

    Science.gov (United States)

    Wilkey, Eric D; Cutting, Laurie E; Price, Gavin R

    2017-03-03

    The development of math skills is a critical component of early education and a strong indicator of later school and economic success. Recent research utilizing population-normed, standardized measures of math achievement suggest that structural and functional integrity of parietal regions, especially the intraparietal sulcus, are closely related to the development of math skills. However, it is unknown how these findings relate to in-school math learning. The present study is the first to address this issue by investigating the relationship between regional differences in grey matter (GM) volume and performance in grade-level mathematics as measured by a state-wide, school-based test of math achievement (TCAP math) in children from 3rd to 8th grade. Results show that increased GM volume in the bilateral hippocampal formation and the right inferior frontal gyrus, regions associated with learning and memory, is associated with higher TCAP math scores. Secondary analyses revealed that GM volume in the left angular gyrus had a stronger relationship to TCAP math in grades 3-4 than in grades 5-8 while the relationship between GM volume in the left inferior frontal gyrus and TCAP math was stronger for grades 5-8. These results suggest that the neuroanatomical architecture related to in-school math achievement differs from that related to math achievement measured by standardized tests, and that the most related neural structures differ as a function of grade level. We suggest, therefore, that the use of school-relevant outcome measures is critical if neuroscience is to bridge the gap to education.

  6. Achieving the optimal performance of the CMS ECAL in Run II

    CERN Document Server

    Sun, Menglei

    2016-01-01

    Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high resolution electron and photon energy measurements. Particularly important are decays of the Higgs boson resulting in electromagnetic particles in the final state. Di-photon events in CMS are also a very important channel in the search for Higgs boson production in association with other particles or in the search for possible new resonances of higher mass. The requirement for high performance electromagnetic calorimetry therefore remains high during LHC Run II. Following the excellent performance achieved in Run~I at a center of mass energy of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) started operating at the LHC in Spring 2015 with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run~II is expected to exceed the levels achieved in Run I, using 25 ns bunch spacing. The average number of concurrent proton-proton collisions per bu...

  7. Achieving the optimal performance of the CMS ECAL in Run II

    CERN Document Server

    Sun, Menglei

    2016-01-01

    Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high resolution electron and photon energy measurements. Particularly important are decays of the Higgs boson resulting in electromagnetic particles in the final state. Di-photon events in CMS are also a very important channel in the search for Higgs boson production in association with other particles or in the search for possible new resonances of higher mass. The requirement for high performance electromagnetic calorimetry therefore remains high during LHC Run II. Following the excellent performance achieved in Run~I at a center of mass energy of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) started operating at the LHC in Spring 2015 with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run~II is expected to exceed the levels achieved in Run I, using 25 ns bunch spacing. The average number of concurrent proton-proton collisions per bu...

  8. When nursing takes ownership of financial outcomes: achieving exceptional financial performance through leadership, strategy, and execution.

    Science.gov (United States)

    Goetz, Kristopher; Janney, Michelle; Ramsey, Kristin

    2011-01-01

    With nurses and unlicensed supportive personnel composing the greatest percentage of the workforce at any hospital, it is not surprising nursing leadership plays an increasing role in the attainment of financial goals. The nursing leadership team at one academic medical center reduced costs by more than $10 million over 4 years while outperforming national benchmarks on nurse-sensitive quality indicators. The most critical success factor in attaining exceptional financial performance is a personal and collective accountability to achieving outcomes. Whether it is financial improvement, advancing patient safety, or ensuring a highly engaged workforce, success will not be attained without thoughtful, focused leadership. The accountability model ensures there is a culture built around financial performance where nurses and leaders think and act, on a daily basis, in a manner necessary to understand opportunities, find answers, and overcome obstacles. While structures, processes, and tools may serve as the means to achieve a target, it is leadership's responsibility to set the right goal and motivate others.

  9. Achieving High Performance in AC-Field Driven Organic Light Sources.

    Science.gov (United States)

    Xu, Junwei; Carroll, David L; Smith, Gregory M; Dun, Chaochao; Cui, Yue

    2016-04-11

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m(2) with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today's OLEDs in performance.

  10. The role of locus of control and achievement motivation in the work performance of black managers

    Directory of Open Access Journals (Sweden)

    A. C. Bothma

    1997-06-01

    Full Text Available The primary objective of this study was to predict the work performance of Black managers by using three measures of Locus of Control and five measures of Achievement Motivation. Work performance was assessed by superiors with the aid of the Performance Appraisal Questionnaire of Schepers (1994 which yields three scores, viz, Work Performance, Creativity/Initiative and Management Skills. The sample comprised 102 Black male employees in supervisory and more senior positions in a diversified and geographically dispersed chemical company. In analysing the data, the three sets of measures were intercorrelated and subjected to a factor analysis. Three factors were identified; amongst others a factor representing work performance. A composite score was accordingly computed which served as the criterion measure in a regression analysis. Furthermore/ a canonical correlation procedure was used to maximise the correlation between the predictor variables and the dependent variables. Two statistically significant canonical correlations were obtained. It was found that both the Locus of Control Inventory and the Achievement Motivation Questionnaire can be used as predictors of work performance as assessed by means of the Performance Appraisal Questionnaire (PA. Opsomming Die primêre doelwit van hierdie studie was om die werkverrigting van Swart bestuurders te voorspel deur gebruik te maak van drie metings van Lokus van Beheer en vyf metings van Prestasiemotivering. Werkverrigting is deur bogeskiktes met behulp van die Prestasiebeoordelingsvraelys van Schepers (1994 beoordeel, wat drie tellings lewer, naamlik Werkverigting, Inisiatief/Kreatiwiteit en Bestuursvaardighede. Die steekproef het uit 102 Swart manlike werknemers in toesighoudende en meer senior posisies in 'n gediversifiseerde en geografies verspreide chemiese maatskappy bestaan. In die ontleding van die data is die drie stelle metings geïterkorreleer en aan 'n faktorontleding onderwerp. Drie

  11. High-Achieving High School Students and Not so High-Achieving College Students: A Look at Lack of Self-Control, Academic Ability, and Performance in College

    Science.gov (United States)

    Honken, Nora B.; Ralston, Patricia A. S.

    2013-01-01

    This study investigated the relationship among lack of self-control, academic ability, and academic performance for a cohort of freshman engineering students who were, with a few exceptions, extremely high achievers in high school. Structural equation modeling analysis led to the conclusion that lack of self-control in high school, as measured by…

  12. Evaluation of dialyzer jacket structure and hollow-fiber dialysis membranes to achieve high dialysis performance.

    Science.gov (United States)

    Hirano, Ayaka; Yamamoto, Ken-ichiro; Matsuda, Masato; Ogawa, Takehito; Yakushiji, Taiji; Miyasaka, Takehiro; Sakai, Kiyotaka

    2011-02-01

    The objective of this study was to determine the optimum dialyzer jacket structure and hollow-fiber dialysis membrane, both of which are indispensable factors for achieving high dialysis performance, by clarifying the relationship between the dialysis performance and the flow of dialysate and blood in a hollow-fiber dialyzer. We evaluated the clearance, dialysate, and blood flow for four commercially available hollow-fiber dialyzers, namely, the APS-15S, APS-15SA, TS-1.6UL, and CX-1.6U. To evaluate dialysate and blood flow, we measured the residence-time distribution of dialysate and blood flow of these dialyzers by the pulse-response method. We also determined the clearances of urea, creatinine, vitamin B(12), and lysozyme to evaluate the dialysis performance of these dialyzers. While the baffle and taper structures allow effective supply of dialysate into the dialyzer jacket, the hollow-fiber shape, inner diameter, and packing density significantly influence the dialysate flow. In dialyzers with long taper-holding slits, the slit area is a key design parameter for achieving optimum dialysate flow. Similarly, the blood flow is significantly influenced by the structure of the inflowing and outflowing blood ports at the header of a dialyzer, and the shape and inner diameter of the hollow fibers. Hollow fibers with smaller inner diameters cause an increase in blood pressure, which causes blood to enter the hollow fibers more easily. The hollow-fiber shape hardly affects the blood flow. While improved dialysate and blood flow cause higher clearance of low molecular-weight substances, higher membrane area and pure-water permeability accelerate internal filtration, thereby causing an increase in the clearance of large molecular-weight substances. © 2010 The Authors. Therapeutic Apheresis and Dialysis © 2010 International Society for Apheresis.

  13. Stagnation-point flow and heat transfer over an exponentially shrinking sheet: A stability analysis

    Science.gov (United States)

    Ismail, Nurul Syuhada; Arifin, Norihan Md.; Bachok, Norfifah; Mahiddin, Norhasimah

    2016-06-01

    Numerical solutions for the stagnation-point flow and heat transfer over an exponentially shrinking sheet have been investigated. The governing boundary layer equations are transformed into an ordinary differential equation using a non-similar transformation. By using the bvp4c solver in MATLAB, the results of the equations can be solved numerically. Numerical results indicate that in certain parameter, the non-unique solutions for the velocity and the temperature do exist. A linear stability analysis shows that only one solution is linearly stable otherwise is unstable. Then, the stability analysis is performed to identify which solution is stable between the two non-unique solutions.

  14. A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A thorough analysis of electric field is carried out so as to verify that a novel dual-electrode plug can build intensive electric field and can improve the main drawbacks of feeble electric field and low ignition efficiency of the traditional plug. With intensive electric field, the proposed novel plug can achieve high performance ignition, resulting in fuel saving and exhaust reduction. Gauss law is applied for electric field analysis to show that intensive electric field can be built by the novel plug. Then, according to Faraday law a lower-voltage ignition feature accomplished by the plug is discussed. Compared with traditional plug, the novel dual-electrode plug has the following advantages. (1 Much higher energy density is built between the plug electrodes, lowering ignition voltage requirement. (2 Electromagnetic interference (EMI problem caused by high ignition voltage is readily resolved. (3 Ignition time delay can be improved. (4 The feature to save fuel consuming is achieved. (5 The exhaust of CO and HC is reduced significantly. Practical measurements are fulfilled to validate the electric field analysis and to demonstrate the features of the proposed dual-electrode plug.

  15. A comprehensive approach to decipher biological computation to achieve next generation high-performance exascale computing.

    Energy Technology Data Exchange (ETDEWEB)

    James, Conrad D.; Schiess, Adrian B.; Howell, Jamie; Baca, Michael J.; Partridge, L. Donald; Finnegan, Patrick Sean; Wolfley, Steven L.; Dagel, Daryl James; Spahn, Olga Blum; Harper, Jason C.; Pohl, Kenneth Roy; Mickel, Patrick R.; Lohn, Andrew; Marinella, Matthew

    2013-10-01

    The human brain (volume=1200cm3) consumes 20W and is capable of performing > 10^16 operations/s. Current supercomputer technology has reached 1015 operations/s, yet it requires 1500m^3 and 3MW, giving the brain a 10^12 advantage in operations/s/W/cm^3. Thus, to reach exascale computation, two achievements are required: 1) improved understanding of computation in biological tissue, and 2) a paradigm shift towards neuromorphic computing where hardware circuits mimic properties of neural tissue. To address 1), we will interrogate corticostriatal networks in mouse brain tissue slices, specifically with regard to their frequency filtering capabilities as a function of input stimulus. To address 2), we will instantiate biological computing characteristics such as multi-bit storage into hardware devices with future computational and memory applications. Resistive memory devices will be modeled, designed, and fabricated in the MESA facility in consultation with our internal and external collaborators.

  16. Magnetohydrodynamic Stagnation Point Flow with a Convective Surface Boundary Condition

    Science.gov (United States)

    Jafar, Khamisah; Ishak, Anuar; Nazar, Roslinda

    2011-09-01

    This study analyzes the steady laminar two-dimensional stagnation point flow and heat transfer of an incompressible viscous fluid impinging normal to a horizontal plate, with the bottom surface of the plate heated by convection from a hot fluid. A uniform magnetic field is applied in a direction normal to the flat plate, with a free stream velocity varying linearly with the distance from the stagnation point. The governing partial differential equations are first transformed into ordinary differential equations, before being solved numerically. The analysis includes the effects of the magnetic parameter, the Prandtl number, and the convective parameter on the heat transfer rate at the surface. Results showed that the heat transfer rate at the surface increases with increasing values of these quantities.

  17. Magnetohydrodynamic stagnation point flow with a convective surface boundary condition

    Energy Technology Data Exchange (ETDEWEB)

    Jafar, Khamisah [Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia). Faculty of Engineering and Built Environment; Ishak, Anuar; Nazar, Roslinda [Universiti Kebangsaan, Bangi, Selangor (Malaysia). School of Mathematical Sciences

    2011-08-15

    This study analyzes the steady laminar two-dimensional stagnation point flow and heat transfer of an incompressible viscous fluid impinging normal to a horizontal plate, with the bottom surface of the plate heated by convection from a hot fluid. A uniform magnetic field is applied in a direction normal to the flat plate, with a free stream velocity varying linearly with the distance from the stagnation point. The governing partial differential equations are first transformed into ordinary differential equations, before being solved numerically. The analysis includes the effects of the magnetic parameter, the Prandtl number, and the convective parameter on the heat transfer rate at the surface. Results showed that the heat transfer rate at the surface increases with increasing values of these quantities. (orig.)

  18. Estimation of Centers and Stagnation points in optical flow fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1997-01-01

    In a topological sense fluid flows are characterised by their stagnation points. Given a temporal sequence of images of fluids we will consider the application of local polynomials to the estimation of smooth fluid flow fields. The normal flow at intensity contours is estimated from the local...... distribution of spatio-temporal energy, which is sampled using a set of spatio-temporal quadrature filters. These observations of normal flows are then integrated into smooth flow fields by locally approximating first order polynomials in the spatial coordinates to the flow vectors. This technique furthermore...... allows us to give a qualitative local description of the flow field and to estimate the position of stagnation points (e.g. nodes, saddles, and centers). We will apply the algorithm to two data sets. The first sequence consists of infrared images from the meteorological satellite Meteosat. Here...

  19. Unsteady conjugated heat transfer near a stagnation point

    Energy Technology Data Exchange (ETDEWEB)

    Drake, D.G.

    1983-01-01

    An analysis is presented for the unsteady thermal processes involved when a plane wall of high thermal conductivity loses heat to a fluid in two-dimensional stagnation point flow against the wall. It is assumed that the rear surface of the wall is insulated and the initial temperature of the wall is greater than that of the fluid. A complete description of the temperature history of the wall is obtained by developing solutions valid for small and large values of the time.

  20. Unsteady conjugated heat transfer near a stagnation point

    Science.gov (United States)

    Drake, D. G.

    An analysis is presented for the unsteady thermal processes involved when a plane wall of high thermal conductivity loses heat to a fluid in two-dimensional stagnation point flow against the wall. It is assumed that the rear surface of the wall is insulated and the initial temperature of the wall is greater than that of the fluid. A complete description of the temperature history of the wall is obtained by developing solutions valid for small and large values of the time.

  1. Possible Origin of Stagnation and Variability of Earth's Biodiversity

    OpenAIRE

    Stollmeier, Frank; Geisel, Theo; Nagler, Jan

    2014-01-01

    The magnitude and variability of Earth's biodiversity have puzzled scientists ever since paleontologic fossil databases became available. We identify and study a model of interdependent species where both endogenous and exogenous impacts determine the nonstationary extinction dynamics. The framework provides an explanation for the qualitative difference of marine and continental biodiversity growth. In particular, the stagnation of marine biodiversity may result from a global transition from ...

  2. Modulated stagnation-point flow and steady streaming

    Science.gov (United States)

    Merchant, Gregory J.; Davis, Stephen H.

    1989-01-01

    Plane stagnation-point flow is modulated in the free stream so that the velocity components are proportional to K(H) + K cos omega t. Similarity solutions of the Navier-Stokes equations are examined using high-frequency asymptotics for K and K(H) of unit order. Special attention is focused on the steady streaming generated in this flow with strongly non-parallel streamlines.

  3. A Novel Hybrid MCDM Procedure for Achieving Aspired Earned Value Project Performance

    Directory of Open Access Journals (Sweden)

    Shou-Yan Chou

    2016-01-01

    Full Text Available A better-performing project gains more subsequent businesses. Many organizations worldwide apply an earned value management (EVM system to monitor and control their projects’ performance. However, a successful EVM application requires handling multiple interinfluenced criteria with feedback effects for decision-making and continuous improvements throughout the application life cycle. The conventional decision approaches assume that preferences between criteria are independent and put their focuses on decision-making. This study employs a hybrid multiple criteria decision-making (HMCDM method to devise a novel procedure to fulfil the deficiencies. The proposed procedure enables us to evaluate interinfluence effects and gap indices among criteria/dimensions/alternatives and then systemize the evaluation results in a context of influential network relation map (INRM. The INRM provides managers with visual information to find a route in making application decisions, while identifying critical gaps for continuous improvements. A numerical example is presented to illustrate the applicability of the proposed procedure. The results show that, by employing the HMCDM method, the proposed procedure can provide organizations with a foundation to ensure that the aspired EVM application outcomes are achieved at different levels within an organization.

  4. Achieving numerical accuracy and high performance using recursive tile LU factorization with partial pivoting

    KAUST Repository

    Dongarra, Jack

    2013-09-18

    The LU factorization is an important numerical algorithm for solving systems of linear equations in science and engineering and is a characteristic of many dense linear algebra computations. For example, it has become the de facto numerical algorithm implemented within the LINPACK benchmark to rank the most powerful supercomputers in the world, collected by the TOP500 website. Multicore processors continue to present challenges to the development of fast and robust numerical software due to the increasing levels of hardware parallelism and widening gap between core and memory speeds. In this context, the difficulty in developing new algorithms for the scientific community resides in the combination of two goals: achieving high performance while maintaining the accuracy of the numerical algorithm. This paper proposes a new approach for computing the LU factorization in parallel on multicore architectures, which not only improves the overall performance but also sustains the numerical quality of the standard LU factorization algorithm with partial pivoting. While the update of the trailing submatrix is computationally intensive and highly parallel, the inherently problematic portion of the LU factorization is the panel factorization due to its memory-bound characteristic as well as the atomicity of selecting the appropriate pivots. Our approach uses a parallel fine-grained recursive formulation of the panel factorization step and implements the update of the trailing submatrix with the tile algorithm. Based on conflict-free partitioning of the data and lockless synchronization mechanisms, our implementation lets the overall computation flow naturally without contention. The dynamic runtime system called QUARK is then able to schedule tasks with heterogeneous granularities and to transparently introduce algorithmic lookahead. The performance results of our implementation are competitive compared to the currently available software packages and libraries. For example

  5. Measuring Emotions in Students' Learning and Performance: The Achievement Emotions Questionnaire (AEQ)

    Science.gov (United States)

    Pekrun, Reinhard; Goetz, Thomas; Frenzel, Anne C.; Barchfeld, Petra; Perry, Raymond P.

    2011-01-01

    Aside from test anxiety scales, measurement instruments assessing students' achievement emotions are largely lacking. This article reports on the construction, reliability, internal validity, and external validity of the Achievement Emotions Questionnaire (AEQ) which is designed to assess various achievement emotions experienced by students in…

  6. High and Low Reading Comprehension Achievers' Strategic Behaviors and Their Relation to Performance in a Reading Comprehension Situation

    Science.gov (United States)

    Dermitzaki, Irini; Andreou, Georgia; Paraskeva, Violetta

    2008-01-01

    This study aimed at investigating the actual strategic behaviors of high and low achievers in reading comprehension and their relation with respective performance. The participants were 45 individually examined third graders, 20 high and 25 low reading comprehension achievers. Cognitive, metacognitive, and motivational aspects of the participants'…

  7. Measuring Metacognition and Reaction Time: Further Findings on the Performances of General Education, Low-Achieving, and Institutionally Raised Students

    Science.gov (United States)

    Al-Hilawani, Yasser A.; Abdullah, Ahmad A.

    2010-01-01

    The purpose of this study was to use the picture format to examine in depth the metacognitive performances and reaction time in general education, low-achieving, and institutionally raised students. Results revealed that institutionally raised students, unlike low-achieving students, took significantly the longest reaction time to finish the test…

  8. A hydrological modeling framework for defining achievable performance standards for pesticides.

    Science.gov (United States)

    Rousseau, Alain N; Lafrance, Pierre; Lavigne, Martin-Pierre; Savary, Stéphane; Konan, Brou; Quilbé, Renaud; Jiapizian, Paul; Amrani, Mohamed

    2012-01-01

    This paper proposes a hydrological modeling framework to define achievable performance standards (APSs) for pesticides that could be attained after implementation of recommended management actions, agricultural practices, and available technologies (i.e., beneficial management practices [BMPs]). An integrated hydrological modeling system, Gestion Intégrée des Bassins versants à l'aide d'un Système Informatisé, was used to quantify APSs for six Canadian watersheds for eight pesticides: atrazine, carbofuran, dicamba, glyphosate, MCPB, MCPA, metolachlor, and 2,4-D. Outputs from simulation runs to predict pesticide concentration under current conditions and in response to implementation of two types of beneficial management practices (reduced pesticide application rate and 1- to 10-m-wide edge-of-field and/or riparian buffer strips, implemented singly or in combination) showed that APS values for scenarios with BMPs were less than those for current conditions. Moreover, APS values at the outlet of watersheds were usually less than ecological thresholds of good condition, when available. Upstream river reaches were at greater risk of having concentrations above a given ecological thresholds because of limited stream flows and overland loads of pesticides. Our integrated approach of "hydrological modeling-APS estimation-ecotoxicological significance" provides the most effective interpretation possible, for management and education purposes, of the potential biological impact of predicted pesticide concentrations in rivers.

  9. How many trials are needed to achieve performance stability of the Timed Up & Go test in patients with hip fracture?

    DEFF Research Database (Denmark)

    Kristensen, Morten T; Ekdahl, Charlotte; Kehlet, Henrik;

    2010-01-01

    To examine the number of trials needed to achieve performance stability of the Timed Up & Go (TUG) test using a standardized walking aid in patients with hip fracture who are allowed full weight bearing (FWB)....

  10. Physical Activity Before School, Cognitive Performance, and Academic Achievement in Dutch Adolescents: Let them Walk or Cycle to School!

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Van Acker, Frederik; Savelberg, Hans; Kirschner, Paul A.

    2014-01-01

    In this study, associations between objectively measured active commuting to school and cognitive performance and academic achievement in Dutch adolescents were investigated. Active commuting to school was found to be positively associated with executive functioning in adolescent girls.

  11. How many trials are needed to achieve performance stability of the Timed Up & Go test in patients with hip fracture?

    DEFF Research Database (Denmark)

    Kristensen, Morten T; Ekdahl, Charlotte; Kehlet, Henrik;

    2010-01-01

    To examine the number of trials needed to achieve performance stability of the Timed Up & Go (TUG) test using a standardized walking aid in patients with hip fracture who are allowed full weight bearing (FWB).......To examine the number of trials needed to achieve performance stability of the Timed Up & Go (TUG) test using a standardized walking aid in patients with hip fracture who are allowed full weight bearing (FWB)....

  12. Tracking Student Achievement in Music Performance: Developing Student Learning Objectives for Growth Model Assessments

    Science.gov (United States)

    Wesolowski, Brian C.

    2015-01-01

    Student achievement growth data are increasingly used for assessing teacher effectiveness and tracking student achievement in the classroom. Guided by the student learning objective (SLO) framework, music teachers are now responsible for collecting, tracking, and reporting student growth data. Often, the reported data do not accurately reflect the…

  13. Tracking Student Achievement in Music Performance: Developing Student Learning Objectives for Growth Model Assessments

    Science.gov (United States)

    Wesolowski, Brian C.

    2015-01-01

    Student achievement growth data are increasingly used for assessing teacher effectiveness and tracking student achievement in the classroom. Guided by the student learning objective (SLO) framework, music teachers are now responsible for collecting, tracking, and reporting student growth data. Often, the reported data do not accurately reflect the…

  14. Performance-Based Music Ensembles' Effects on Academic Achievement: A Correlational Study

    Science.gov (United States)

    Stevenson, Timothy Francis

    2013-01-01

    As increasing student achievement levels for all learners continues to drive the focus of education, identifying strategies and opportunities to accomplish this goal becomes progressively more important. This study explored the concepts of self-efficacy, self-efficacy for self-regulated learning, and self-efficacy for academic achievement in…

  15. Academic Achievement Performance of University Students with Disability: Exploring the Influence of Non-Academic Factors

    Science.gov (United States)

    Dryer, Rachel; Henning, Marcus A.; Tyson, Graham A.; Shaw, Rosemary

    2016-01-01

    This study examined whether: (1) the non-academic constructs of psychological well-being, motivation to learn and quality of life (QOL) explained the variance in the academic achievement of students with disability; and (2) students with a mental health disability (MHD) differed from students with other disability on academic achievement and on…

  16. Achievement First: Developing a Teacher Performance Management System That Recognizes Excellence

    Science.gov (United States)

    Curtis, Rachel

    2011-01-01

    Teachers are the single most important school-related factor in students' learning, and improving student learning is the single most important goal at Achievement First (AF), a fast-growing public charter school network in the Northeast. To achieve this goal, the AF team has worked to establish a common understanding of effective instructional…

  17. Performance-Based Music Ensembles' Effects on Academic Achievement: A Correlational Study

    Science.gov (United States)

    Stevenson, Timothy Francis

    2013-01-01

    As increasing student achievement levels for all learners continues to drive the focus of education, identifying strategies and opportunities to accomplish this goal becomes progressively more important. This study explored the concepts of self-efficacy, self-efficacy for self-regulated learning, and self-efficacy for academic achievement in…

  18. To Master or Perform? Exploring Relations between Achievement Goals and Conceptual Change Learning

    Science.gov (United States)

    Ranellucci, John; Muis, Krista R.; Duffy, Melissa; Wang, Xihui; Sampasivam, Lavanya; Franco, Gina M.

    2013-01-01

    Background: Research is needed to explore conceptual change in relation to achievement goal orientations and depth of processing. Aims: To address this need, we examined relations between achievement goals, use of deep versus shallow processing strategies, and conceptual change learning using a think-aloud protocol. Sample and Method:…

  19. Relating Teacher Candidate Performance to Their Students' Subject Specific Academic Achievement Using TWS Methodology

    Science.gov (United States)

    Fenster, Mark J.; Judd, Diane L.

    2008-01-01

    Teacher education preparation programs are under pressure from the public to provide evidence that their programs and teacher candidates are improving student achievement. However, the connections between teacher education preparation programs, teacher candidates' evaluation, and student achievement are often hard to disentangle from other…

  20. Relationships of cognitive and metacognitive learning strategies to mathematics achievement in four high-performing East Asian education systems.

    Science.gov (United States)

    Areepattamannil, Shaljan; Caleon, Imelda S

    2013-01-01

    The authors examined the relationships of cognitive (i.e., memorization and elaboration) and metacognitive learning strategies (i.e., control strategies) to mathematics achievement among 15-year-old students in 4 high-performing East Asian education systems: Shanghai-China, Hong Kong-China, Korea, and Singapore. In all 4 East Asian education systems, memorization strategies were negatively associated with mathematics achievement, whereas control strategies were positively associated with mathematics achievement. However, the association between elaboration strategies and mathematics achievement was a mixed bag. In Shanghai-China and Korea, elaboration strategies were not associated with mathematics achievement. In Hong Kong-China and Singapore, on the other hand, elaboration strategies were negatively associated with mathematics achievement. Implications of these findings are briefly discussed.

  1. Stagnation region gas film cooling: Spanwise angled injection from multiple rows of holes. [gas turbine engines

    Science.gov (United States)

    Luckey, D. W.; Lecuyer, M. R.

    1981-01-01

    The stagnation region of a cylinder in a cross flow was used in experiments conducted with both a single row and multiple rows of spanwise angled (25 deg) coolant holes for a range of the coolant blowing ratio with a freestream to wall temperature ratio approximately equal to 1.7 and R(eD) = 90,000. Data from local heat flux measurements are presented for injection from a single row located at 5 deg, 22.9 deg, 40.8 deg, 58.7 deg from stagnation using a hole spacing ratio of S/d(o) = 5 and 10. Three multiple row configurations were also investigated. Data are presented for a uniform blowing distribution and for a nonuniform blowing distribution simulating a plenum supply. The data for local Stanton Number reduction demonstrated a lack of lateral spreading by the coolant jets. Heat flux levels larger than those without film cooling were observed directly behind the coolant holes as the blowing ratio exceeded a particular value. The data were spanwise averaged to illustrate the influence of injection location, blowing ratio and hole spacing. The large values of blowing ratio for the blowing distribution simulating a plenum supply resulted in heat flux levels behind the holes in excess of the values without film cooling. An increase in freestream turbulence intensity from 4.4 to 9.5 percent had a negligible effect on the film cooling performance.

  2. Catalytic performance and thermostability of chloroperoxidase in reverse micelle: achievement of a catalytically favorable enzyme conformation.

    Science.gov (United States)

    Wang, Yali; Wu, Jinyue; Ru, Xuejiao; Jiang, Yucheng; Hu, Mancheng; Li, Shuni; Zhai, Quanguo

    2011-06-01

    The catalytic performance of chloroperoxidase (CPO) in peroxidation of 2, 2'-azinobis-(-3 ethylbenzothiazoline-6-sulfononic acid) diammonium salt (ABTS) and oxidation of indole in a reverse micelle composed of surfactant-water-isooctane-pentanol was investigated and optimized in this work. Some positive results were obtained as follows: the peroxidation activity of CPO was enhanced 248% and 263%, while oxidation activity was enhanced 215% and 222% in cetyltrimethylammonium bromide (CTABr) reverse micelle medium and dodecyltrimethylammonium bromide (DTABr) medium, respectively. Thermostability was also greatly improved in reverse micelle: at 40 °C, CPO essentially lost all its activity after 5 h incubation, while 58-76% catalytic activity was retained for both reactions in the two reverse micelle media. At 50 °C, about 44-75% catalytic activity remained for both reactions in reverse micelle after 2 h compared with no observed activity in pure buffer under the same conditions. The enhancement of CPO activity was dependent mainly on the surfactant concentration and structure, organic solvent ratio (V(pentanol)/V(isooctane)), and water content in the reverse micelle. The obtained kinetic parameters showed that the catalytic turnover frequency (k(cat)) was increased in reverse micelle. Moreover, the lower K(m) and higher k(cat)/K(m) demonstrated that both the affinity and specificity of CPO to substrates were improved in reverse micelle media. Fluorescence, circular dichroism (CD) and UV-vis spectra assays indicated that a catalytically favorable conformation of enzyme was achieved in reverse micelle, including the strengthening of the protein α-helix structure, and greater exposure of the heme prosthetic group for easy access of the substrate in bulk solution. These results are promising in view of the industrial applications of this versatile biological catalyst.

  3. Dye visualization near a three-dimensional stagnation point: application to the vortex breakdown bubble

    DEFF Research Database (Denmark)

    Brøns, Morten; Thompson, M. C.; Hourigan, K.

    2009-01-01

    , and consequently its open nature, can be explained by the very small imperfections that are present in any experimental rig. Distinct from this, here it is shown that even for a perfectly axisymmetric flow and breakdown bubble, the combined effect of dye diffusion and the inevitable small errors in the dye......An analytical model, based on the Fokker-Planck equation, is constructed of the dye visualization expected near a three-dimensional stagnation point in a swirling fluid flow. The model is found to predict dye traces that oscillate in density and position in the meridional plane in which swirling...... of the rig. Thus, when interpreting dye-visualization patterns in steady flow, even if axisymmetric flow can be achieved, it is important to take into account the relative diffusivity of the dye and the accuracy of its injection....

  4. Injection-induced turbulence in stagnation-point boundary layers

    Science.gov (United States)

    Park, C.

    1984-02-01

    A theory is developed for the stagnation point boundary layer with injection under the hypothesis that turbulence is produced at the wall by injection. From the existing experimental heat transfer rate data obtained in wind tunnels, the wall mixing length is deduced to be a product of a time constant and an injection velocity. The theory reproduces the observed increase in heat transfer rates at high injection rates. For graphite and carbon-carbon composite, the time constant is determined to be 0.0002 sec from the existing ablation data taken in an arc-jet tunnel and a balistic range.

  5. Pressure and temperature development in solar heating system during stagnation

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Chen, Ziqian

    2010-01-01

    This paper presents an investigation of stagnation in solar collectors and the effects it will have on the collector loop. At a laboratory test stand at the Technical University of Denmark, a pressurized solar collector loop was designed to test different numbers of collectors and different designs...... of the pipes of the solar collector loop. During the investigation the pre-pressure of the expansion vessel and system filling pressure was changed. The investigations showed that a large pressurised expansion vessel will protect the collector loop from critically high temperatures as long as the solar...

  6. Pressure and temperature development in solar heating system during stagnation

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Chen, Ziqian

    2010-01-01

    of the pipes of the solar collector loop. During the investigation the pre-pressure of the expansion vessel and system filling pressure was changed. The investigations showed that a large pressurised expansion vessel will protect the collector loop from critically high temperatures as long as the solar......This paper presents an investigation of stagnation in solar collectors and the effects it will have on the collector loop. At a laboratory test stand at the Technical University of Denmark, a pressurized solar collector loop was designed to test different numbers of collectors and different designs...

  7. Stagnation Region Heat Transfer Augmentation at Very High Turbulence Levels

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Forrest [University of North Dakota; Kingery, Joseph E. [University of North Dakota

    2015-06-17

    A database for stagnation region heat transfer has been extended to include heat transfer measurements acquired downstream from a new high intensity turbulence generator. This work was motivated by gas turbine industry heat transfer designers who deal with heat transfer environments with increasing Reynolds numbers and very high turbulence levels. The new mock aero-combustor turbulence generator produces turbulence levels which average 17.4%, which is 37% higher than the older turbulence generator. The increased level of turbulence is caused by the reduced contraction ratio from the liner to the exit. Heat transfer measurements were acquired on two large cylindrical leading edge test surfaces having a four to one range in leading edge diameter (40.64 cm and 10.16 cm). Gandvarapu and Ames [1] previously acquired heat transfer measurements for six turbulence conditions including three grid conditions, two lower turbulence aero-combustor conditions, and a low turbulence condition. The data are documented and tabulated for an eight to one range in Reynolds numbers for each test surface with Reynolds numbers ranging from 62,500 to 500,000 for the large leading edge and 15,625 to 125,000 for the smaller leading edge. The data show augmentation levels of up to 136% in the stagnation region for the large leading edge. This heat transfer rate is an increase over the previous aero-combustor turbulence generator which had augmentation levels up to 110%. Note, the rate of increase in heat transfer augmentation decreases for the large cylindrical leading edge inferring only a limited level of turbulence intensification in the stagnation region. The smaller cylindrical leading edge shows more consistency with earlier stagnation region heat transfer results correlated on the TRL (Turbulence, Reynolds number, Length scale) parameter. The downstream regions of both test surfaces continue to accelerate the flow but at a much lower rate than the leading edge. Bypass transition occurs

  8. Possible Origin of Stagnation and Variability of Earth's Biodiversity

    Science.gov (United States)

    Stollmeier, Frank; Geisel, Theo; Nagler, Jan

    2014-06-01

    The magnitude and variability of Earth's biodiversity have puzzled scientists ever since paleontologic fossil databases became available. We identify and study a model of interdependent species where both endogenous and exogenous impacts determine the nonstationary extinction dynamics. The framework provides an explanation for the qualitative difference of marine and continental biodiversity growth. In particular, the stagnation of marine biodiversity may result from a global transition from an imbalanced to a balanced state of the species dependency network. The predictions of our framework are in agreement with paleontologic databases.

  9. Stagnation of electron flow by a nonlinearly generated whistler wave

    CERN Document Server

    Taguchi, Toshihiro; Mima, Kunioki

    2016-01-01

    Relativistic electron beam transport through a high-density, magnetized plasma is studied numerically and theoretically. An electron beam injected into a cold plasma excites Weibel and two-stream instabilities that heat the beam and saturate. In the absence of an applied magnetic field, the heated beam continues to propagate. However, when a magnetic field of particular strength is applied along the direction of beam propagation, a secondary instability of off-angle whistler modes is excited. These modes then couple nonlinearly creating a large amplitude parallel propagating whistler that stops the beam. In this letter, we will show the phenomena in detail and explain the mechanism of whistler mediated beam stagnation.

  10. Avoiding Intellectual Stagnation: The Starship as an Expander of Minds

    CERN Document Server

    Crawford, Ian A

    2015-01-01

    Interstellar exploration will advance human knowledge and culture in multiple ways. Scientifically, it will advance our understanding of the interstellar medium, stellar astrophysics, planetary science and astrobiology. In addition, significant societal and cultural benefits will result from a programme of interstellar exploration and colonisation. Most important will be the cultural stimuli resulting from expanding the horizons of human experience, and increased opportunities for the spread and diversification of life and culture through the Galaxy. Ultimately, a programme of interstellar exploration may be the only way for human (and post-human) societies to avoid the intellectual stagnation predicted for the "end of history".

  11. Stagnation and interpenetration of laser-created colliding plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Pollaine, S.M.; Albritton, J.R.; Kauffman, R.; Keane, C.J. (Lawrence Livermore National Lab., CA (USA)); Berger, R.L.; Bosch, R.; Delameter, N.D.; Failor, B.H. (KMS Fusion, Inc., Ann Arbor, MI (USA))

    1990-11-05

    A KMS laser experiment collides Aluminum (A1) and Magnesium (Mg) plasmas. The measurements include electron density, time and space resolved Ly-alpha and He-alpha lines of Al and Mg, and x-ray images. These measurements were analyzed with a hydrodynamic code, LASNEX, and a special two-fluid code OFIS. The results strongly suggest that at early times, the Al interpenetrates the counterstreaming Mg and deposits in the dense Mg region. At late times, the Al plasma stagnates against the Mg plasma.

  12. Standard Test Method for Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the calculation from heat transfer theory of the stagnation enthalpy from experimental measurements of the stagnation-point heat transfer and stagnation pressure. 1.2 Advantages 1.2.1 A value of stagnation enthalpy can be obtained at the location in the stream where the model is tested. This value gives a consistent set of data, along with heat transfer and stagnation pressure, for ablation computations. 1.2.2 This computation of stagnation enthalpy does not require the measurement of any arc heater parameters. 1.3 Limitations and ConsiderationsThere are many factors that may contribute to an error using this type of approach to calculate stagnation enthalpy, including: 1.3.1 TurbulenceThe turbulence generated by adding energy to the stream may cause deviation from the laminar equilibrium heat transfer theory. 1.3.2 Equilibrium, Nonequilibrium, or Frozen State of GasThe reaction rates and expansions may be such that the gas is far from thermodynamic equilibrium. 1.3.3 Noncat...

  13. A Comprehensive Review of the Literature on the Effects of Breakfast on Mental Performance and Scholastic Achievement.

    Science.gov (United States)

    Purnell, James P.

    A review of the literature on the effects of breakfast on mental performance and scholastic achievement reveals a dichotomy between the theoretical and the empirical literature. Whereas theoretical considerations maintain that breakfast makes a significant difference in mental performance in the late morning hours, empirical evidence can be…

  14. The Influence of the Antecedent Variable on the Teachers' Performance through Achievement Motivation in Senior High School

    Science.gov (United States)

    Dewi, Erni R.; Bundu, Patta; Tahmir, Suradi

    2016-01-01

    This study aims at analysing whether the antecedent variable directly affects the performance of the high school teachers or not. In addition, this research strives to find out whether the antecedent variable indirectly affects the teachers' performance through the achievement motivation of the high school teachers. It was a quantitative research…

  15. Achievable Performance and Effective Interrogator Design for SAW RFID Sensor Tags

    Science.gov (United States)

    Barton Richard J.

    2012-01-01

    current generation tags limits the performance in a cluttered sensing environment. That is, as more SAW-based sensors are added to the environment, numerous tag responses are superimposed at the receiver and decoding all or even a subset of the telemetry becomes increasingly difficult. Background clutter generated by reflectors other than the sensors themselves is also a problem, as is multipath interference and signal distortion, but the limiting factor in many remote sensing applications can be expected to be tag mutual interference. This problem may be greatly mitigated by proper design of the SAW tag waveform, but that remains an open research problem, and in the meantime, several other related questions remain to be answered including: (1) What are the fundamental relationships between tag parameters such as bit-rate, time-bandwidth-product, SNR, and achievable collision resolution? (2) What are the differences in optimal or near-optimal interrogator designs between noise-limited environments and interference-limited environments? (3) What are the performance characteristics of different interrogator designs in term of parameters such as transmitter power level, range, and number of interfering tags? In this paper, we will present the results of a research effort aimed at providing at least partial answers to all of these questions.

  16. Correlation between academic achievement goal orientation and the performance of Malaysian students in an Indian medical school.

    Science.gov (United States)

    Barkur, Rajashekar Rao; Govindan, Sreejith; Kamath, Asha

    2013-01-01

    According to goal orientation theory, achievement goals are defined as the terminal point towards which one's efforts are directed. The four academic achievement goal orientations commonly recognised are mastery, performance approach, performance avoidance and work avoidance. The objective of this study was to understand the goal orientation of second year undergraduate medical students and how this correlates with their academic performance. The study population consisted of 244 second year Bachelor of Medicine and Bachelor of Surgery (MBBS) students of Melaka Manipal Medical College, Manipal campus, Manipal University, India. Students were categorised as high performers and low performers based on their first year university examination marks. Their goal orientations were assessed through a validated questionnaire developed by Was et al. These components were analysed by independent sample t-test and correlated to their first year university examination marks. Confirmatory component factor analysis extracted four factors, which accounted for 40.8% of the total variance in goal orientation. The performance approach goal orientation alone explained 16.7% of the variance followed by mastery (10.8%), performance avoidance (7.7%) and work avoidance (5.7%). The Cronbach's alpha for 19 items, which contributed to internal consistency of the tool, was observed to be 0.635. A strong positive correlation was shown between performance approach, performance avoidance and work avoidance orientations. Of the four goal orientations, only the mean scores in work avoidance orientation differed for low performers and high performers (5.0 vs. 4.3; P = 0.0003). Work avoidance type of goal orientation among the low performer group may account for their lower performance compared with high performer group. This indicates that academic achievement goal orientation may play a role in the performance of undergraduate medical students.

  17. School Achievement and Performance in Chilean High Schools: The Mediating Role of Subjective Wellbeing in School-Related Evaluations

    Directory of Open Access Journals (Sweden)

    Verónica López

    2017-07-01

    Full Text Available School achievement gaps and school failure are problematic issues in Latin America, and are mainly explained by the socio-economic status (SES of the students. What schools can do to improve school achievement and reduce school failure is a critical issue, both for school management and teacher training. In this study, we present the association of individual and school-related socio-emotional variables with school achievement and performance, controlling for the effects of SES. A probabilistic sample of 4,964 students, drawn from 191 schools enrolled in year 10 in urban areas of Chile, answered questionnaires assessing subjective wellbeing, social wellbeing in school, school climate, school social wellbeing and students’ perceptions of teachers’ wellbeing. Using structural equation modeling, and controlling for SES, we modeled subjective wellbeing as a mediator of the relationship between school-related variables, such as school climate and perception of teacher’s wellbeing, and (a school achievement, and (b school performance. School achievement was computed as a product of (a the probability of passing the school year, and (b the percentage of yearly attendance at school. Data on school achievement was drawn from administrative registries from the Chilean Ministry of Education. School performance was computed as the estimated grade point average (GPA at the end of the school year, based on the students’ previous 5-year GPAs, and was also obtained through administrative data of the last 5 years. Findings reveal the mediating role of subjective wellbeing in the relationship between school-related evaluations (students’ social wellbeing at school, their perception of teachers’ wellbeing and school climate and school achievement. For school achievement, two variables were mediated (students’ social wellbeing at school and school climate. However, for school performance, no significant mediations were found. We conclude that, on the

  18. Association between scores in high school, aptitude and achievement exams and early performance in health science college

    Directory of Open Access Journals (Sweden)

    Al-Alwan Ibrahim

    2009-01-01

    Full Text Available This retrospective study was carried out to assess the correlation between admi-ssion criteria to health science colleges, namely, final high school grade and Saudi National Apti-tude and Achievement exams, and early academic performance in these colleges. The study inclu-ded 91 male students studying in the two-year pre-professional program at the King Saud bin Abdulaziz University for Health Sciences (KSAU-HS, Riyadh, Saudi Arabia. Records of these students were used to extract relevant information and their academic performance (based on the grade point average achieved at the end of the first semester of the pre-professional program, which were analytically studied. Pearson correlation coefficient was used to assess the associa-tions between the different scores. SPSS statistical program (version 12.0 was used for data ana-lyses. We found a strong correlation between the academic performance and the Achievement Exam, Aptitude Exam and high school final grade, with Pearson Correlation Coefficients of 0.96, 0.93, 0.87, respectively. The Saudi National Achievement Exam showed the most significant correla-tion. Our results indicate that academic performance showed good correlation with the admission criteria used, namely final high school grade, Saudi National Aptitude and Achievement Exams.

  19. Toward a more social understanding of achievement goals: The interpersonal effects of mastery and performance goals

    NARCIS (Netherlands)

    Poortvliet, P.M.; Darnon, C.

    2010-01-01

    The current article presents an overview of recent research into social outcomes that accompany the pursuit of achievement goals. On the basis of investigations in various subdisciplines of psychology, we conclude that mastery goals—striving to improve one’s own performance—lead to investments in ex

  20. The Relationship between Victimization at School and Achievement: The Cusp Catastrophe Model for Reading Performance

    Science.gov (United States)

    Sideridis, Georgios D.; Antoniou, Faye; Stamovlasis, Dimitrios; Morgan, Paul L.

    2013-01-01

    We evaluated the relationship between victimization and academic achievement from a nonlinear perspective using a cusp catastrophe model. Participants were 62 students with identified learning disabilities (LD) using statewide criteria in Greece. Students participated in a 2-year cohort-sequential design. Reading assessments involved measures of…

  1. Analysis of achievable capacity in irregularly-placed high performance mesh nodes

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-09-01

    Full Text Available challenge. This paper derives the achievable capacity limit of such HPNs’ placements. The analytical results show that the network capacity increases with the irregularity of HPNs placements, the number of antennas as well as the multiplicity of radios per...

  2. Differentiating Low Performance of the Gifted Learner: Achieving, Underachieving, and Selective Consuming Students

    Science.gov (United States)

    Figg, Stephanie D.; Rogers, Karen B.; McCormick, John; Low, Renae

    2012-01-01

    The study aimed to empirically verify findings from qualitative studies that showed selective consumers could be distinguished from underachievers with regard to academic self-perception and thinking style preference. Participants, gifted males from an independent secondary boys' school in Sydney, Australia, were categorized as achieving,…

  3. Improving Low Achievers' Academic Performance at University by Changing the Social Value of Mastery Goals

    Science.gov (United States)

    Dompnier, Benoît; Darnon, Céline; Meier, Emanuele; Brandner, Catherine; Smeding, Annique; Butera, Fabrizio

    2015-01-01

    Recent research has shown that, in a university context, mastery goals are highly valued and that students may endorse these goals either because they believe in their utility (i.e., social utility), in which case mastery goals are positively linked to achievement, or to create a positive image of themselves (i.e., social desirability), in which…

  4. Do Children in Montessori Schools Perform Better in the Achievement Test? A Taiwanese Perspective

    Science.gov (United States)

    Peng, Hsin-Hui; Md-Yunus, Sham'ah

    2014-01-01

    The study examines whether elementary school students in Taiwan who had received Montessori education achieved significantly higher scores on tests of language arts, math, and social studies than students who attended non-Montessori elementary programs. One hundred ninety six children in first, second, and third grade participated in the study.…

  5. Faculty Sense of Academic Optimism and Its Relationship to Students' Achievement in Well Performing High Schools

    Science.gov (United States)

    Cromartie, Michael Tyrone

    2013-01-01

    The aim of this study was to determine the organizational characteristics and behaviors that contribute to sustaining a culture of academic optimism as a mechanism of student achievement. While there is a developing research base identifying both the individual elements of academic optimism as well as the academic optimism construct itself as…

  6. Do Children in Montessori Schools Perform Better in the Achievement Test? A Taiwanese Perspective

    Science.gov (United States)

    Peng, Hsin-Hui; Md-Yunus, Sham'ah

    2014-01-01

    The study examines whether elementary school students in Taiwan who had received Montessori education achieved significantly higher scores on tests of language arts, math, and social studies than students who attended non-Montessori elementary programs. One hundred ninety six children in first, second, and third grade participated in the study.…

  7. Immigrant Children's Educational Achievement in Western Countries : Origin, Destination, and Community Effects on Mathematical Performance

    NARCIS (Netherlands)

    Levels, Mark; Dronkers, Jaap; Kraaykamp, Gerbert

    2008-01-01

    ICS Radboud University Nijmegen This article explores the extent to which macro-level characteristics of destination countries, origin countries, and immigrant communities help explain differences in immigrant children’s educational achievement. Using data from the 2003 PISA survey, we analyze the m

  8. The magnetohydrodynamic stagnation point flow of a nanofluid over a stretching/shrinking sheet with suction.

    Directory of Open Access Journals (Sweden)

    Syahira Mansur

    Full Text Available The magnetohydrodynamic (MHD stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian motion parameter and the thermophoresis parameter reduces the heat transfer rate at the surface.

  9. The magnetohydrodynamic stagnation point flow of a nanofluid over a stretching/shrinking sheet with suction.

    Science.gov (United States)

    Mansur, Syahira; Ishak, Anuar; Pop, Ioan

    2015-01-01

    The magnetohydrodynamic (MHD) stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian motion parameter and the thermophoresis parameter reduces the heat transfer rate at the surface.

  10. Nonlinear radiative heat transfer to stagnation-point flow of Sisko fluid past a stretching cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Masood [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Malik, Rabia, E-mail: rabiamalik.qau@gmail.com [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Department of Mathematics and Statistics, International Islamic University Islamabad 44000 (Pakistan); Hussain, M. [Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Islamabad 44000 (Pakistan)

    2016-05-15

    In the present paper, we endeavor to perform a numerical analysis in connection with the nonlinear radiative stagnation-point flow and heat transfer to Sisko fluid past a stretching cylinder in the presence of convective boundary conditions. The influence of thermal radiation using nonlinear Rosseland approximation is explored. The numerical solutions of transformed governing equations are calculated through forth order Runge-Kutta method using shooting technique. With the help of graphs and tables, the influence of non-dimensional parameters on velocity and temperature along with the local skin friction and Nusselt number is discussed. The results reveal that the temperature increases however, heat transfer from the surface of cylinder decreases with the increasing values of thermal radiation and temperature ratio parameters. Moreover, the authenticity of numerical solutions is validated by finding their good agreement with the HAM solutions.

  11. The Magnetohydrodynamic Stagnation Point Flow of a Nanofluid over a Stretching/Shrinking Sheet with Suction

    Science.gov (United States)

    Mansur, Syahira; Ishak, Anuar; Pop, Ioan

    2015-01-01

    The magnetohydrodynamic (MHD) stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian motion parameter and the thermophoresis parameter reduces the heat transfer rate at the surface. PMID:25760733

  12. Patterns and predictors of adolescent academic achievement and performance in a sample of children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Langberg, Joshua M; Molina, Brooke S G; Arnold, L Eugene; Epstein, Jeffery N; Altaye, Mekibib; Hinshaw, Stephen P; Swanson, James M; Wigal, Timothy; Hechtman, Lily

    2011-01-01

    The current study examined predictors of academic achievement, measured by standardized test scores, and performance, measured by school grades, in adolescents (Mn age = 16.8) who met diagnostic criteria for Attention-Deficit/Hyperactivity Disorder (ADHD)-Combined type in early childhood (Mn age = 8.5; N = 579). Several mediation models were also tested to determine whether ADHD medication use, receipt of special education services, classroom performance, homework completion, or homework management mediated the relationship between symptoms of ADHD and academic outcomes. Childhood predictors of adolescent achievement differed from those for performance. Classroom performance and homework management mediated the relationship between symptoms of inattention and academic outcomes.

  13. Achievement Investment Prowess: Identifying Cost Efficient Higher Performing Maine Public Schools

    Science.gov (United States)

    Batista, Ida A.

    2006-01-01

    Throughout the United States the debate has been frequent, intense, and at times adversarial over how to fund education adequately. Maine has been trying to identify higher performing schools in the hope that practices that contribute to success at higher performing schools can be adapted at similar schools throughout the state. The 1997…

  14. Examining Relationships between Achievement Goals, Study Strategies, and Class Performance in Educational Psychology

    Science.gov (United States)

    Cao, Li; Nietfeld, John L.

    2007-01-01

    This mixed methods study examined the relationships between students' learning goals, performance goals, study strategies, and test performances over a 14-week undergraduate course in educational psychology. Sixty undergraduate students provided goals at the beginning of the semester and reflected on their goals, study strategies, and test…

  15. Provider performance measures in private and public programs: achieving meaningful alignment with flexibility to innovate.

    Science.gov (United States)

    Higgins, Aparna; Veselovskiy, German; McKown, Lauren

    2013-08-01

    In recent years there has been a significant expansion in the use of provider performance measures for quality improvement, payment, and public reporting. Using data from a survey of health plans, we characterize the use of such performance measures by private payers. We also compare the use of these measures among selected private and public programs. We studied twenty-three health plans with 121 million commercial enrollees--66 percent of the national commercial enrollment. The health plans reported using 546 distinct performance measures. There was much variation in the use of performance measures in both private and public payment and care delivery programs, despite common areas of focus that included cardiovascular conditions, diabetes, and preventive services. We conclude that policy makers and stakeholders who seek less variability in the use of performance measures to increase consistency should balance this goal with the need for flexibility to meet the needs of specific populations and promote innovation.

  16. Participation and Performance Reporting for the Alternate Assessment Based on Modified Achievement Standards (AA-MAS). Technical Report 58

    Science.gov (United States)

    Albus, Deb; Thurlow, Martha L.; Lazarus, Sheryl S.

    2011-01-01

    This report examines publicly reported participation and performance data for the alternate assessment based on modified achievement standards (AA-MAS). The authors' analysis of these data included all states publicly reporting AA-MAS data, regardless of whether they had received approval to use the results for Title I accountability calculations.…

  17. A University Engagement Model for Achieving Technology Adoption and Performance Improvement Impacts in Healthcare, Manufacturing, and Government

    Science.gov (United States)

    McKinnis, David R.; Sloan, Mary Anne; Snow, L. David; Garimella, Suresh V.

    2014-01-01

    The Purdue Technical Assistance Program (TAP) offers a model of university engagement and service that is achieving technology adoption and performance improvement impacts in healthcare, manufacturing, government, and other sectors. The TAP model focuses on understanding and meeting the changing and challenging needs of those served, always…

  18. The Relationship of Selected Measures of Proprioception to Physical Growth, Motor Performance, and Academic Achievement in Young Children.

    Science.gov (United States)

    Haubenstricker, John L.; Milne, D. Conrad

    This study investigates the relationship of selected measures of proprioception to measures of physical growth, motor performance, and academic achievement in young children. Measures were obtained from 321 boys and girls attending kindergarten and first and second grade. Sample correlation matrices were computed on all variables at each grade…

  19. The Relationship between Students' Reading Performance on Diagnostic Assessments and the Third Grade Reading Achievement Test in Ohio

    Science.gov (United States)

    Hollinger, Jamie L.

    2009-01-01

    The purpose of this correlational study was twofold: to examine the relationship of students' reading performance on six different diagnostic reading assessments and the third grade Ohio Reading Achievement Test; and to assist educators in choosing the diagnostic assessments that best identify students at risk of failing the third grade Ohio…

  20. Active commuting to school, cognitive performance, and academic achievement: an observational study in Dutch adolescents using accelerometers

    NARCIS (Netherlands)

    Van Dijk, Martin; De Groot, Renate; Van Acker, Frederik; Savelberg, Hans; Kirschner, Paul A.

    2014-01-01

    Background: The current study examined the associations between active commuting to school, cognitive performance, and academic achievement in Dutch adolescents. In addition, it was explored whether these associations were moderated by sex and mediated by depressive symptoms. Methods: Students in gr

  1. Relationships of Cognitive and Metacognitive Learning Strategies to Mathematics Achievement in Four High-Performing East Asian Education Systems

    Science.gov (United States)

    Areepattamannil, Shaljan; Caleon, Imelda S.

    2013-01-01

    The authors examined the relationships of cognitive (i.e., memorization and elaboration) and metacognitive learning strategies (i.e., control strategies) to mathematics achievement among 15-year-old students in 4 high-performing East Asian education systems: Shanghai-China, Hong Kong-China, Korea, and Singapore. In all 4 East Asian education…

  2. Conscientiousness, Achievement Striving, and Intelligence as Performance Predictors in a Sample of German Psychology Students: Always a Linear Relationship?

    Science.gov (United States)

    Ziegler, Matthias; Knogler, Maximilian; Buhner, Markus

    2009-01-01

    Studies on the interface between cognitive ability (intelligence) and personality in the prediction of academic performance have yielded mixed results so far. Especially an interaction between conscientiousness (and its facet achievement striving) and intelligence has been investigated. The hypothesis is that conscientiousness enhances the impact…

  3. Prior Mathematics Achievement, Cognitive Appraisals and Anxiety as Predictors of Finnish Students' Later Mathematics Performance and Career Orientation

    Science.gov (United States)

    Kyttala, Minna; Bjorn, Piia Maria

    2010-01-01

    The aim of this two-year longitudinal study was to investigate the role and impact of prior mathematics performance, cognitive appraisals and mathematics-specific, affective anxiety in determining later mathematics achievement and future career orientation among Finnish adolescents. The basic ideas of the control-value theory, assumed to be…

  4. Pilot Study: EatFit Impacts Sixth Graders' Academic Performance on Achievement of Mathematics and English Education Standards

    Science.gov (United States)

    Shilts, Mical Kay; Lamp, Cathi; Horowitz, Marcel; Townsend, Marilyn S.

    2009-01-01

    Objective: Investigate the impact of a nutrition education program on student academic performance as measured by achievement of education standards. Design: Quasi-experimental crossover-controlled study. Setting: California Central Valley suburban elementary school (58% qualified for free or reduced-priced lunch). Participants: All sixth-grade…

  5. Rise, stagnation, and rise of Danish women's life expectancy

    DEFF Research Database (Denmark)

    Lindahl-Jacobsen, Rune; Rau, Roland; Jeune, Bernard

    2016-01-01

    favor forecasts that hinge on cohort differences. We use a combination of age decomposition and exchange of survival probabilities between countries to study the remarkable recent history of female life expectancy in Denmark, a saga of rising, stagnating, and now again rising lifespans. The gap between...... female life expectancy in Denmark vs. Sweden grew to 3.5 y in the period 1975-2000. When we assumed that Danish women born 1915-1945 had the same survival probabilities as Swedish women, the gap remained small and roughly constant. Hence, the lower Danish life expectancy is caused by these cohorts...... or later. Because it is difficult to disentangle period effects from cohort effects, demographers, epidemiologists, actuaries, and other population scientists often disagree about cohort effects' relative importance. In particular, some advocate forecasts of life expectancy based on period trends; others...

  6. Toward a science of exceptional achievement: attaining superior performance through deliberate practice.

    Science.gov (United States)

    Ericsson, K Anders; Nandagopal, Kiruthiga; Roring, Roy W

    2009-08-01

    Exceptional performance is frequently attributed to genetic differences in talent. Since Sir Francis Galton's book, Hereditary Genius, many scientists have cited heritable factors that set limits of performance and only allow some individuals to attain exceptional levels. However, thus far these accounts have not explicated the causal processes involved in the activation and expression of unique genes in DNA that lead to the emergence of distinctive physiological attributes and cognitive capacities (innate talent). This article argues on the basis of our current knowledge that it is possible to account for the development of elite performance among healthy children without recourse to innate talent (genetic endowment)--excepting the innate determinants of body size. Our account is based on the expert-performance approach and proposes that the distinctive characteristics of exceptional performers are the result of adaptations to extended and intense practice activities that selectively activate dormant genes that are contained within all healthy individuals' DNA. Furthermore, the theoretical framework of expert performance explains the apparent emergence of early talent by identifying factors that influence starting ages for training and the accumulated engagement in sustained extended deliberate practice, such as motivation, parental support, and access to the best training environments and teachers. In sum, our empirical investigations and extensive reviews show that the development of expert performance will be primarily constrained by individuals' engagement in deliberate practice and the quality of the available training resources.

  7. Use of performance curves in estimating number of procedures required to achieve proficiency in coronary angiography

    DEFF Research Database (Denmark)

    Räder, Sune B E W; Jørgensen, Erik; Bech, Bo;

    2011-01-01

    media volume were used as indicators of quality of performance. We analyzed data from 4,200 coronary angiographies. Performance curves of seven trainees were compared with recommended reference levels and to those of seven interventional cardiologists. Results: On average, the number of procedures.......001 for all parameters. To approach the experts' level of DAP and contrast media use, trainees need 394 and 588 procedures, respectively. Performance curves showed large individual differences in the development of competence. Conclusion: On average, trainees needed 300 procedures to reach sufficient level...... needed for trainees to reach recommended reference levels was estimated as 226 and 353, for DAP and use of contrast media, respectively. After 300 procedures, trainees' procedure time, fluoroscopy time, DAP, and contrast media volume were significantly higher compared with experts' performance, P

  8. Locus of Control and Achievement Motivation as Moderators of the Expectancy-Academic Performance Relationship

    Science.gov (United States)

    Batlis, Nick C.; Waters, L. K.

    1973-01-01

    Expectancy theory predictions of course performance were tested for a sample of 195 undergraduates; significant prediction was attained for the total sample using a log linear expectancy model. (Author)

  9. A novel approach to achieving significant reverberation control in performance halls

    Science.gov (United States)

    Conant, David A.; Chu, William

    2005-09-01

    Conventional methods for achieving broadband, variable sound absorption in large halls normally include heavy application of sound-absorptive drapery and/or thick fibrous panels, applied near available surfaces below, at, and in volumes above the catwalk plane. Occasionally, direct adjustments to room air volume are also provided to effect double-sloped decays. The novel method described here combines carefully located, broad scattering and absorption in singular architectural elements and was applied to a new, 1200-seat concert hall. A change of 0.70 s RT60 in midfrequency is achieved in a visually dramatic manner while neither materially changing room volume nor introducing often-maligned drapery. The aggregate of reverberation control methodologies employed reduces the unoccupied RT60 at midfrequencies from about 3.2 to 1.7 s in this space programed principally for music, including pipe organ. Results of MLS measurements including binaural measurements and binaural recordings of anechoic material and CATT-acoustic modeling and auralizations are discussed.

  10. NEMO5: Achieving High-end Internode Communication for Performance Projection Beyond Moore's Law

    CERN Document Server

    Andrawis, Robert; Charles, James; Fang, Jianbin; Fonseca, Jim; He, Yu; Klimeck, Gerhard; Jiang, Zhengping; Kubis, Tillmann; Mejia, Daniel; Lemus, Daniel; Povolotskyi, Michael; Rubiano, Santiago Alonso Perez; Sarangapani, Prasad; Zeng, Lang

    2015-01-01

    Electronic performance predictions of modern nanotransistors require nonequilibrium Green's functions including incoherent scattering on phonons as well as inclusion of random alloy disorder and surface roughness effects. The solution of all these effects is numerically extremely expensive and has to be done on the world's largest supercomputers due to the large memory requirement and the high performance demands on the communication network between the compute nodes. In this work, it is shown that NEMO5 covers all required physical effects and their combination. Furthermore, it is also shown that NEMO5's implementation of the algorithm scales very well up to about 178176CPUs with a sustained performance of about 857 TFLOPS. Therefore, NEMO5 is ready to simulate future nanotransistors.

  11. Coping with stress and cognitive interference in student teachers performance as important factors influencing their achievement

    Directory of Open Access Journals (Sweden)

    Cirila Peklaj

    2001-06-01

    Full Text Available The purpose of our study was to investigate the relations between student teachers' strategies for coping with stressful situations, cognitive interference factors and successfulness of presentation of student teachers' seminar work. There were 135 student teachers participating in the study. At the beginning of the semester they filled in the Way of Coping Questionnaire (Folkman & Lazarus, 1988. After their presentation of seminar theme they reported about the cognitive interference factors during the presentation (distractive factors and intrusive thoughts. Different aspects of their performance were also evaluated by the teacher according to the well-known criteria. The analysis of the results showed significant correlations between certain ways of coping, cognitive interference factors and success of performance. Further statistical analysis showed significant differences in experiencing distractive factors and intrusive thoughts during presentation between students with low, medium and high performance success. The importance of successful strategies for coping with verbal presentation and the implications for student teacher education are discussed.

  12. The role of mechanization and integration of manufacturing processes in achieving operational performance

    DEFF Research Database (Denmark)

    Naqvi, Syed Turab Haider; Farooq, Sami; Johansen, John

    2014-01-01

    Small manufacturing firms are the dominant organization type for most of the developed countries. However, these firms have not been the focus of research and their strategic and operational needs are not extensively addressed by the academic community. Therefore, this research aims at empirically...... finding the impact of mechanization and integration of manufacturing processes and systems on operational performance in small Danish manufacturing firms. We use data of 357 small Danish manufacturing firms and empirically found distinct impact of mechanization and integration of systems on operational...... performance in context of production to order (PTO) and production to stock (PTS) strategies....

  13. Use of neurofeedback to achieve human performance enhancement in the nuclear power industry

    Energy Technology Data Exchange (ETDEWEB)

    Freer, P. [Freer Logic (United States); Chandler, K. [Univ. of Windsor, Dept. of Kinesiology, Windsor, Ontario (Canada); Lane, L.; Templeton, R. [Ontario Power Generation, Toronto, Ontario (Canada)

    2007-07-01

    The nuclear industry has spent many millions of dollars to provide training to personnel to operate our nuclear facilities. However, even with excellent training programs, candidates often fail examinations. For many, the debilitating effects of performance anxiety are contributing factors. Neurofeedback technology instantly presents psychophysiological feedback to the trainee while the trainee is performing a training task. This feedback can teach the trainee to effectively cope with environmental and psychological stressors. We hypothesize that NF training can help NPPs resolve staffing and training challenges while yielding a high ROI by ultimately improving success rates for Certification training candidates. (author)

  14. Short Circuits or Superconductors? Effects of Group Composition on High-Achieving Students' Science Assessment Performance.

    Science.gov (United States)

    Webb, Noreen M.; Nemer, Kariane Mari; Zuniga, Stephen

    2002-01-01

    Studied the effects of group ability composition (homogeneous versus heterogeneous) on group processes and outcomes for high-ability students completing science assessments. Results for 83 high ability students show the quality of group functioning serves as the strongest predictor of high-ability students' performance and explained much of the…

  15. Initial Teacher Education: Does Self-Efficacy Influence Candidate Teacher Academic Achievement and Future Career Performance?

    Science.gov (United States)

    Shawer, Saad F.

    2013-01-01

    This quantitative investigation examined the influence of low and high self-efficacy on candidate teacher academic performance in a foreign language teaching methodology course through testing the speculation that high self-efficacy levels would improve pedagogical-content knowledge (PCK). Positivism guided the research design at the levels of…

  16. Believe, and you will achieve: changes over time in self-efficacy, engagement, and performance.

    Science.gov (United States)

    Ouweneel, Else; Schaufeli, Wilmar B; Le Blanc, Pascale M

    2013-07-01

    In order to answer the question whether changes in students' self-efficacy levels co-vary with similar changes in engagement and performance, a field study and an experimental study were conducted among university students. In order to do this, we adopted a subgroup approach. We created "natural" (Study 1) and manipulated (Study 2) subgroups based upon their change in self-efficacy over time and examined whether these subgroups showed similar changes over time in engagement and performance. The results of both studies are partly in line with Social Cognitive Theory, in that they confirm that changes in self-efficacy may have a significant impact on students' changes in cognition and motivation (i.e. engagement), as well as behavior (i.e. performance). More specifically, our results show that students' increases/decreases in self-efficacy were related to corresponding increases/decreases in their study engagement and task performance over time. Examining the consequences of changes in students' self-efficacy levels seems promising, both for research and practice.

  17. The role of supply chain action programs in achieving operational performance excellence

    DEFF Research Database (Denmark)

    Farooq, Sami; Dukovska-Popovska, Iskra; Boer, Harry

    2009-01-01

    This paper investigates the effects of five individual supply chain action programs on cost and speed aspects of procurement and manufacturing performance. The study is based on the IMSS-IV database. As should be expected, supply chain action programs have stronger effects on externally oriented...

  18. The role of supply chain action programs in achieving operational performance excellence

    DEFF Research Database (Denmark)

    Farooq, Sami; Dukovska-Popovska, Iskra; Boer, Harry

    2009-01-01

    This paper investigates the effects of five individual supply chain action programs on cost and speed aspects of procurement and manufacturing performance. The study is based on the IMSS-IV database. As should be expected, supply chain action programs have stronger effects on externally oriented ...

  19. Aural Dictation Affects High Achievement in Sight Singing, Performance and Composition Skills

    Science.gov (United States)

    Rogers, Melissa

    2013-01-01

    The nature of skill acquisition has long been of interest to music educators. This study considers the research context for relationships between aural dictation, sight singing, performance and composition skills. Then, relationships between these skill areas are quantitatively investigated using data from the Australian New South Wales Music 2…

  20. "High" Achievers? Cannabis Access and Student Performance. CEP Discussion Paper No. 1340

    Science.gov (United States)

    Marie, Olivier; Zölitz, Ulf

    2015-01-01

    This paper investigates how legal cannabis access affects student performance. Identification comes from an exceptional policy introduced in the city of Maastricht which discriminated legal access based on individuals' nationality. We apply a difference-in-difference approach using administrative panel data on over 54,000 course grades of local…

  1. Achievable capacity design for irregular and clustered high performance mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-11-01

    Full Text Available and locations of terminal users [10]. Moreover, typical rural based wireless networks can be described by (i) long single hop links, (ii) limited and unreliable energy sources, and (iii) clustered distribution of Internet users [11]. The main problem... constitutes the need to increase capacity of community owned existing wireless broadband networks so that multimedia services can be delivered to remote and rural areas without losing connectivity [2]. Fig. 1: High Performance Node (HPN) TM [10] Fig. 2...

  2. How to Achieve the Best SRF Performance: (Practical) Limitations and Possible Solutions

    CERN Document Server

    Antoine, Claire Z.

    2014-07-17

    This chapter presents in the first part the requirement for the surface preparation of RF Niobium cavities and its justification in term s of physical origin of limitation (e.g. cleanliness and field emission, influence of the surface treatments, morphology and surface damage, etc.). In the second part we discuss the different models describing the ultimate limits of SRF cavities, and we present one of the possible ways to overcome Niobium monopoly toward higher performances.

  3. Achievement motivation, competitiveness and sports performance in a team of sportsmen soccer players between 14 and 24 years old

    Directory of Open Access Journals (Sweden)

    Alejo García-Naveira

    2011-05-01

    Full Text Available In order to identify to what extent competitiveness trait is related to sport performance in soccer, and to what extent the age and sport category can influence these variables, a descriptive cross-sectional study has been developed. The variables age, sport category, sport performance, achievement motivation (Me, motivation to avoid the failure (Mef and competitiveness trait have been assessed in 151 men soccer players (between 14 and 24 y.o. of a Spanish sport club. The results indicated that the sport performance ascends with age. Consequently, a direct relationship between the sport category and the performance has been observed. Me, Mef and competitiveness trait have been associated with the performance and has varied based on the sport category. No correlation between Me, Mef, competitiveness and age of the sportsmen has been found

  4. When performance-approach goals predict academic achievement and when they do not: a social value approach.

    Science.gov (United States)

    Dompnier, Benoît; Darnon, Céline; Butera, Fabrizio

    2013-09-01

    Research on achievement goal promotion at University has shown that performance-approach goals are perceived as a means to succeed at University (high social utility) but are not appreciated (low social desirability). We argue that such a paradox could explain why research has detected that performance-approach goals consistently predict academic grades. First-year psychology students answered a performance-approach goal scale with standard, social desirability and social utility instructions. Participants' grades were recorded at the end of the semester. Results showed that the relationship between performance-approach goals and grades was inhibited by the increase of these goals' social desirability and facilitated by the increase of their social utility, revealing that the predictive validity of performance-approach goals depends on social value. © 2013 The British Psychological Society.

  5. Motivation and performance within a collaborative computer-based modeling task: Relations between student's achievement goal orientation, self-efficiacy, cognitive processing and achievement.

    NARCIS (Netherlands)

    Sins, Patrick H.M.; van Joolingen, Wouter; Savelsbergh, Elwin R.; van Hout-Wolters, Bernadette

    2008-01-01

    Purpose of the present study was to test a conceptual model of relations among achievement goal orientation, self-efficacy, cognitive processing, and achievement of students working within a particular collaborative task context. The task involved a collaborative computer-based modeling task. In ord

  6. Motivation and performance within a collaborative computer-based modeling task: Relations between students' achievement goal orientation, self-efficacy, cognitive processing and achievement

    NARCIS (Netherlands)

    Sins, P.H.M.|info:eu-repo/dai/nl/29637119X; van Joolingen, W.R.; Savelsbergh, E.R.|info:eu-repo/dai/nl/17345853X; van Hout-Wolters, B.H.A.M.

    2008-01-01

    Purpose of the present study was to test a conceptual model of relations among achievement goal orientation, self-efficacy, cognitive processing, and achievement of students working within a particular collaborative task context. The task involved a collaborative computer-based modeling task. In ord

  7. Motivation and performance within a collaborative computer-based modeling task: Relations between students' achievement goal orientation, self-efficacy, cognitive processing and achievement

    NARCIS (Netherlands)

    Sins, P.H.M.; van Joolingen, W.R.; Savelsbergh, E.R.; van Hout-Wolters, B.H.A.M.

    2008-01-01

    Purpose of the present study was to test a conceptual model of relations among achievement goal orientation, self-efficacy, cognitive processing, and achievement of students working within a particular collaborative task context. The task involved a collaborative computer-based modeling task. In ord

  8. Motivation and performance within a collaborative computer-based modeling task: relations between students’ achievement goal orientation, self-efficacy, cognitive processing, and achievement

    NARCIS (Netherlands)

    Sins, Patrick H.M.; Joolingen, van Wouter R.; Savelsbergh, Elwin R.; Hout-Wolters, van Bernadette

    2008-01-01

    Purpose of the present study was to test a conceptual model of relations among achievement goal orientation, self-efficacy, cognitive processing, and achievement of students working within a particular collaborative task context. The task involved a collaborative computer-based modeling task. In ord

  9. A conceptual framework for achieving performance enhancing drug compliance in sport.

    Science.gov (United States)

    Donovan, Robert J; Egger, Garry; Kapernick, Vicki; Mendoza, John

    2002-01-01

    There has been, and continues to be, widespread international concern about athletes' use of banned performance enhancing drugs (PEDs). This concern culminated in the formation of the World Anti-Doping Agency (WADA) in November 1999. To date, the main focus on controlling the use of PEDs has been on testing athletes and the development of tests to detect usage. Although athletes' beliefs and values are known to influence whether or not an athlete will use drugs, little is known about athletes' beliefs and attitudes, and the limited empirical literature shows little use of behavioural science frameworks to guide research methodology, results interpretation, and intervention implications. Mindful of this in preparing its anti-doping strategy for the 2000 Olympics, the Australian Sports Drug Agency (ASDA) in 1997 commissioned a study to assess the extent to which models of attitude-behaviour change in the public health/injury prevention literature had useful implications for compliance campaigns in the sport drug area. A preliminary compliance model was developed from three behavioural science frameworks: social cognition models; threat (or fear) appeals; and instrumental and normative approaches. A subsequent review of the performance enhancing drug literature confirmed that the overall framework was consistent with known empirical data, and therefore had at least face validity if not construct validity. The overall model showed six major inputs to an athlete's attitudes and intentions with respect to performance enhancing drug usage: personality factors, threat appraisal, benefit appraisal, reference group influences, personal morality and legitimacy. The model demonstrated that a comprehensive, fully integrated programme is necessary for maximal effect, and provides anti-doping agencies with a structured framework for strategic planning and implementing interventions. Programmes can be developed in each of the six major areas, with allocation of resources to each

  10. Studies on the impact of achievement motivation on childrens’ performance in the FEW-2

    OpenAIRE

    Peggy Beuthan; Willi Geser; Claudia Schusterschitz

    2012-01-01

    If children in occupational diagnostics solve tasks with suboptimal test motivation, the results of such tests can be falsified. Against that background, the present research aims were to examine, whether there is an influence of children’s test motivation on their performance in the FEW-2, and if their test motivation can be improved by promising a reward. In an experimental field study of 80 healthy and German-speaking children, at the age of 4 to 6 years, data on test motivation were colle...

  11. High-performance gas sensing achieved by mesoporous tungsten oxide mesocrystals with increased oxygen vacancies

    KAUST Repository

    Wang, Dong

    2013-01-01

    The inner structure of W18O49 mesocrystals was observed by electron microscopy with the help of ultramicrotomy and focused ion beam techniques. The results showed that these mesocrystals contain irregular mesopores formed through partial fusion of self-assembled nanowires, and consequently have long-range structural ordering in one dimension and short-range ordering in the other two dimensions. The W18O 49 mesocrystals exhibit superior performance in gas sensing applications, which is considered to be associated with the presence of more oxygen vacancy sites in the unique mesoporous structure. © 2013 The Royal Society of Chemistry.

  12. The role of mechanization and integration of manufacturing processes in achieving operational performance

    DEFF Research Database (Denmark)

    Naqvi, Syed Turab Haider; Farooq, Sami; Johansen, John

    2014-01-01

    finding the impact of mechanization and integration of manufacturing processes and systems on operational performance in small Danish manufacturing firms. We use data of 357 small Danish manufacturing firms and empirically found distinct impact of mechanization and integration of systems on operational......Small manufacturing firms are the dominant organization type for most of the developed countries. However, these firms have not been the focus of research and their strategic and operational needs are not extensively addressed by the academic community. Therefore, this research aims at empirically...

  13. The tzero electric sports car : how electric vehicles can achieve both high performance and high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, A.N.; Gage, T.B. [AC Propulsion, San Dimas, CA (United States)

    2000-07-01

    The development of a high-performance electric sports car by AC Propulsion was described along with a status report on the progress in developing the product-certified version. The development of the tzero car began in 1996. In-use testing and safety certification of prototypes is currently underway. The tzero is powered by a high-performance induction motor operated at 37 per cent higher peak current than allowed in a standard system since periods of peak power are limited to only a few seconds. The car, which can accelerate from 0 to 60 mph in 4.1 seconds, is considered to be one of the most energy-efficient cars on the road. Since the tzero will likely be sold without subsidy and since the market size for the tzero is expected to be small, in the order of 1000 units per year, it will have to be sold at a high enough price to cover the costs of small-volume production. AC Propulsion is hopeful that it may even be the first electric vehicle to be sold at a profit. Its technology and image are expected to present examples for other electric vehicles. The paper also included a comprehensive technical description of the car and its systems, such as the power electronics unit, traction converter, charger, auxiliary power supply, 12V battery, recharge interface, battery pack, battery modules and powertrain control. 4 tabs., 15 figs.

  14. Studies on the impact of achievement motivation on childrens’ performance in the FEW-2

    Directory of Open Access Journals (Sweden)

    Peggy Beuthan

    2012-09-01

    Full Text Available If children in occupational diagnostics solve tasks with suboptimal test motivation, the results of such tests can be falsified. Against that background, the present research aims were to examine, whether there is an influence of children’s test motivation on their performance in the FEW-2, and if their test motivation can be improved by promising a reward. In an experimental field study of 80 healthy and German-speaking children, at the age of 4 to 6 years, data on test motivation were collected and the FEW-2 was performed. To answer the research questions correlation analysis and t-tests for unpaired samples were carried out. The correlation analyses showed an influence of the motivation of the test on the outcomes of the FEW-2, if the claim of other cognitive services, such as, for example, the concentration of power was increased. According to the findings of the t-tests, the reward did not lead to a heightened test motivation amongst the participants of the experimental group. The revealed influence of test motivation on the outcomes of the FEW-2 underlines the necessity to test for test motivation in view of a reliable and valid neuropsychological diagnostic.

  15. Grid Computing: A Collaborative Approach in Distributed Environment for Achieving Parallel Performance and Better Resource Utilization

    Directory of Open Access Journals (Sweden)

    Sashi Tarun

    2011-01-01

    Full Text Available From the very beginning various measures are taken or consider for better utilization of available limited resources in the computer system for operational environment, this is came in consideration because most of the time our system get free and not able to exploit the system resource/capabilities as whole cause low performance. Parallel Computing can work efficiently, where operations are handled by multi-processors independently or efficiently, without any other processing capabilities. All processing unit’s works in a parallel fashioned and increases the system throughput without any resource allocation problem among different processing units. But this is limited and effective within a single machine. Today in this computing world, maintaining and establishing high speed computational work environment in a distributed scenario seems to be a challenging task because this environment made all operations by not depending on single resources but by interacting with otherresources in the vast network architecture. All current resource management system can only work smoothly if they apply these resources within their clusters, local organizations or disputed among many users who needs processing power, but for vast distributed environment performing various operational activities seems to be difficult because data is physically not maintained in a centralized location, it is geographically dispersed on multiple remote computers systems. Computers in the distributed environment have to depend on multiple resources for their task completion. Effective performance with high availability of resources to each computer in this speedy distributed computational environment is the major concern. To solve this problem a new approach is coined called “Grid Computing” environment. Grid uses a Middleware to coordinate disparate resources across a network, allows users to function as a virtual whole and make computing fast. In this paper I want to

  16. Robotic Observatory System Design-Specification Considerations for Achieving Long-Term Sustainable Precision Performance

    Science.gov (United States)

    Wray, J. D.

    2003-05-01

    The robotic observatory telescope must point precisely on the target object, and then track autonomously to a fraction of the FWHM of the system PSF for durations of ten to twenty minutes or more. It must retain this precision while continuing to function at rates approaching thousands of observations per night for all its years of useful life. These stringent requirements raise new challenges unique to robotic telescope systems design. Critical design considerations are driven by the applicability of the above requirements to all systems of the robotic observatory, including telescope and instrument systems, telescope-dome enclosure systems, combined electrical and electronics systems, environmental (e.g. seeing) control systems and integrated computer control software systems. Traditional telescope design considerations include the effects of differential thermal strain, elastic flexure, plastic flexure and slack or backlash with respect to focal stability, optical alignment and angular pointing and tracking precision. Robotic observatory design must holistically encapsulate these traditional considerations within the overall objective of maximized long-term sustainable precision performance. This overall objective is accomplished through combining appropriate mechanical and dynamical system characteristics with a full-time real-time telescope mount model feedback computer control system. Important design considerations include: identifying and reducing quasi-zero-backlash; increasing size to increase precision; directly encoding axis shaft rotation; pointing and tracking operation via real-time feedback between precision mount model and axis mounted encoders; use of monolithic construction whenever appropriate for sustainable mechanical integrity; accelerating dome motion to eliminate repetitive shock; ducting internal telescope air to outside dome; and the principal design criteria: maximizing elastic repeatability while minimizing slack, plastic deformation

  17. Rankings of International Achievement Test Performance and Economic Strength: Correlation or Conjecture?

    Directory of Open Access Journals (Sweden)

    CHRISTOPHER H. TIENKEN

    2008-04-01

    Full Text Available Examining a popular political notion, this article presents results from a series of Spearman Rho calculations conducted to investigate relationships between countries’ rankings on international tests of mathematics and science and future economic competitiveness as measured by the 2006 World Economic Forum’s Growth Competitiveness Index (GCI. The study investigated the existence of relationships between international test rankings from three different time periods during the last 50 years of U.S. education policy development (i.e., 1957–1982, 1983–2000, and 2001–2006 and 2006 GCI ranks. It extends previous research on the topic by investigating how GCI rankings in the top 50 percent and bottom 50 percent relate to rankings on international tests for the countries that participated in each test. The study found that the relationship between ranks on international tests of mathematics and science and future economic strength is stronger among nations with lower-performing economies. Nations with strong economies, such as the United States, demonstrate a weaker, nonsignificant relationship.

  18. Transuranics Laboratory, achievements and performance; Laboratorio de Transuranicos, logros y fundamento

    Energy Technology Data Exchange (ETDEWEB)

    Gasco, C.; Anton, M. P.

    2004-07-01

    The Marine and Aquatic Radioecology Group (MARG) was established in 1985 with the main scope of analysing the consequences of the Palomares accident in the adjacent Mediterranean ecosystem. From then on and up to now , this Group has extended its investigations to other European marine environments, such as the Spanish Mediterranean margin, the Artic and the Atlantic. The main research of long-lived radionuclides (plutonium, americium and Cs-137) determining the orography influence, riverine inputs and their geo-chemical associations. This group is currently accomplishing new challenges on the radioecology field such as the development of techniques for transuranics speciation to determine their geo-chemical association to the main sediment compounds. Natural and anthropogenic radionuclides distribution on salt-marsh areas affected by dry-wet periods is being studied as well as the possibilities of fusing crossed techniques for dating recent sediments (pollen, anthropogenic, ''210 Pb, etc). The Laboratory performance description, the procedures used, calculations, challenges and gaps are described in this report. (Author) 22 refs.

  19. ITC SOLUTIONS TO ACHIEVE PERFORMANCE AND EFFICIENCY OF HEALTH SERVICES: ONLINE VIRTUAL CLINIC

    Directory of Open Access Journals (Sweden)

    Adina BĂLAN

    2010-01-01

    Full Text Available The digital era modified the way people work, how the information and the informational resources are defined and organized. The organization which holds, uses and correctly reproduces the piece of information, the knowledge, the intellectual capital, becomes a leader in the proper field of activity. Following the actual tendencies in the digital era connected to the exchange of professional information, I can say that the exchange and sharing of digital information in a global multitude of interconnected computers are essential instruments that can contribute to the development and consolidation of the intellectual potential of the organization. This is why, the access of the individuals to information is an actual requirement of the development of the Romanian society in the context of globalization and world implication o contemporary processes and phenomena. The Digital integration eliminates the barriers that traditionally suppress the circuit of the medical information, lets the goods and services circulate to and from Romania by promoting efficiency as final purpose. Performance is needed in the health system, the transformation of the system of medical services by bringing the benefits of the medical science and technology to all individuals from every community. In order to accomplish these expectations it is needed that all the components that form the health system look at it as a whole and subscribe to modern solutions for improvement so that the quality of health should raise to an unprecedented level. Even if health systems differ from country to country from the organizational and financial point of view, they face the same challenges and problems, respectively the supply of medical care of better quality and keeping under control the health expenses. The use of information and communication technology in the field of medical assistance in order to stock, share, transmit and analyze clinical data and knowledge is more necessary

  20. Achieving organisational competence for clinical leadership: the role of high performance work systems.

    Science.gov (United States)

    Leggat, Sandra G; Balding, Cathy

    2013-01-01

    While there has been substantial discussion about the potential for clinical leadership in improving quality and safety in healthcare, there has been little robust study. The purpose of this paper is to present the results of a qualitative study with clinicians and clinician managers to gather opinions on the appropriate content of an educational initiative being planned to improve clinical leadership in quality and safety among medical, nursing and allied health professionals working in primary, community and secondary care. In total, 28 clinicians and clinician managers throughout the state of Victoria, Australia, participated in focus groups to provide advice on the development of a clinical leadership program in quality and safety. An inductive, thematic analysis was completed to enable the themes to emerge from the data. Overwhelmingly the participants conceptualised clinical leadership in relation to organisational factors. Only four individual factors, comprising emotional intelligence, resilience, self-awareness and understanding of other clinical disciplines, were identified as being important for clinical leaders. Conversely seven organisational factors, comprising role clarity and accountability, security and sustainability for clinical leaders, selective recruitment into clinical leadership positions, teamwork and decentralised decision making, training, information sharing, and transformational leadership, were seen as essential, but the participants indicated they were rarely addressed. The human resource management literature includes these seven components, with contingent reward, reduced status distinctions and measurement of management practices, as the essential organisational underpinnings of high performance work systems. The results of this study propose that clinical leadership is an organisational property, suggesting that capability frameworks and educational programs for clinical leadership need a broader organisation focus. The paper

  1. Rise, stagnation, and rise of Danish women's life expectancy.

    Science.gov (United States)

    Lindahl-Jacobsen, Rune; Rau, Roland; Jeune, Bernard; Canudas-Romo, Vladimir; Lenart, Adam; Christensen, Kaare; Vaupel, James W

    2016-04-12

    Health conditions change from year to year, with a general tendency in many countries for improvement. These conditions also change from one birth cohort to another: some generations suffer more adverse events in childhood, smoke more heavily, eat poorer diets, etc., than generations born earlier or later. Because it is difficult to disentangle period effects from cohort effects, demographers, epidemiologists, actuaries, and other population scientists often disagree about cohort effects' relative importance. In particular, some advocate forecasts of life expectancy based on period trends; others favor forecasts that hinge on cohort differences. We use a combination of age decomposition and exchange of survival probabilities between countries to study the remarkable recent history of female life expectancy in Denmark, a saga of rising, stagnating, and now again rising lifespans. The gap between female life expectancy in Denmark vs. Sweden grew to 3.5 y in the period 1975-2000. When we assumed that Danish women born 1915-1945 had the same survival probabilities as Swedish women, the gap remained small and roughly constant. Hence, the lower Danish life expectancy is caused by these cohorts and is not attributable to period effects.

  2. Stagnating Jatropha Biofuel Development in Southwest China: An Institutional Approach

    Directory of Open Access Journals (Sweden)

    Jia Li

    2014-05-01

    Full Text Available Biodiesel from jatropha has been considered as a promising alternative to fossil fuels for some time. Consequently, China started promoting jatropha as one of the options to meet its ever-increasing energy consumption, and the Chinese biodiesel industry also gained interest. However, the excitement of the biofuel industry in jatropha faded after it did not bring about the expected results. This article investigates the stagnation in jatropha development and production for biodiesel in China, using two detailed case studies of jatropha biofuel production in southeast China. It is found that the underdeveloped biodiesel policy and regulation, such as a rather late formulation of standards for biodiesel (especially the B5 and the absence of mandatory targets, is an important reason for hampering jatropha development. Besides that, lack of financial support undermined sustained jatropha planting at the farm level and lack of sustained commitment from state-owned enterprises or private companies over a long time span further contributed to jatropha project’s failure. Better implementation of the rule of law, mandatory blending requirements, hazard insurance, as well as continuous financial support, might improve the continuation of jatropha plantation schemes.

  3. Achieving high performance polymer optoelectronic devices for high efficiency, long lifetime and low fabrication cost

    Science.gov (United States)

    Huang, Jinsong

    This thesis described three types of organic optoelectronic devices: polymer light emitting diodes (PLED), polymer photovoltaic solar cell, and organic photo detector. The research in this work focuses improving their performance including device efficiency, operation lifetime simplifying fabrication process. With further understanding in PLED device physics, we come up new device operation model and improved device architecture design. This new method is closely related to understanding of the science and physics at organic/metal oxide and metal oxide/metal interface. In our new device design, both material and interface are considered in order to confine and balance all injected carriers, which has been demonstrated very be successful in increasing device efficiency. We created two world records in device efficiency: 18 lm/W for white emission fluorescence PLED, 22 lm/W for red emission phosphorescence PLED. Slow solvent drying process has been demonstrated to significantly increase device efficiency in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C 61-butyric acid methyl ester (PCBM) mixture polymer solar cell. From the mobility study by time of flight, the increase of efficiency can be well correlated to the improved carrier transport property due to P3HT crystallization during slow solvent drying. And it is found that, similar to PLED, balanced carrier mobility is essential in high efficient polymer solar cell. There is also a revolution in our device fabrication method. A unique device fabrication method is presented by an electronic glue based lamination process combined with interface modification as a one-step polymer solar cell fabrication process. It can completely skip the thermal evaporation process, and benefit device lifetime by several merits: no air reactive. The device obtained is metal free, semi-transparent, flexible, self-encapsulated, and comparable efficiency with that by regular method. We found the photomultiplication (PM) phenomenon in C

  4. Lean Management Promoting Achievement of Performance Excellences%精益管理助推卓越绩效落地

    Institute of Scientific and Technical Information of China (English)

    郑锦秀

    2016-01-01

    The paper analyzes the relationship between performance excellences and lean management, and how to lean management support the achievement of performance excellence. The paper also discusses the way and the key points. It has certain reference significance to the enterprise which pursues the excellence performance.%文章分析了卓越绩效、精益管理的关系,对精益管理如何支撑卓越绩效落地,以及实施途径和要点进行了探讨,对推行卓越绩效的企业具有一定的借鉴意义。

  5. Big Sochi in soviet historiography of the stagnation period (1970s

    Directory of Open Access Journals (Sweden)

    Nikita A. Kulikov

    2010-10-01

    Full Text Available The article examines native historiographical heritage of the Stagnation Period (1970-s, in which have found their reflection the changes, occurred in Sochi, shown as the unique soviet resort.

  6. Stagnation-point flow of the Walters' B' fluid with slip

    OpenAIRE

    Labropulu, F.; Husain, I; Chinichian, M.

    2004-01-01

    The steady two-dimensional stagnation point flow of a non-Newtonian Walters' B' fluid with slip is studied. The fluid impinges on the wall either orthogonally or obliquely. A finite difference technique is employed to obtain solutions.

  7. Safe, Non-Corrosive Dielectric Fluid for Stagnating Radiator Thermal Control System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon proposes to develop a single-loop, non-toxic, stagnating active pumped loop thermal control design for NASA's Orion or Lunar Surface Access Module (LSAM)...

  8. Predictive Gust Load Alleviation Control Using Leading Edge Stagnation Point Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc proposes an R&D effort to develop a Gust Load Alleviation (GLA) control system using a novel Leading Edge Stagnation Point (LESP) sensor...

  9. Analytic Solution for Magnetohydrodynamic Stagnation Point Flow towards a Stretching Sheet

    Institute of Scientific and Technical Information of China (English)

    DING Qi; ZHANG Hong-Qing

    2009-01-01

    A steady two-dimensional magnetohydrodynamic stagnation point flow towards a stretching sheet with variable surface temperature is investigated. The analytic solution is obtained by homotopy analysis method. Theconvergence region is computed and the feature of the solution is discussed.

  10. Safe, Non-Corrosive Dielectric Fluid for Stagnating Radiator Thermal Control System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon Space Development Corporation proposes to develop a single-loop, non-toxic, active pumped radiator design with robust, reliable operation near stagnation...

  11. Institutionel stagnation i hertugdømmet Slesvig 1840-1860

    DEFF Research Database (Denmark)

    Clausen, Thomas

    2017-01-01

    This article provides a study of the framework conditions for trade and industry in the Duchy of Schleswig in the middle of the 19th century. Grounded on theory of institutional economics the main argument of the paper is that Schleswig on a range of parameters suffered from stagnation in the dev...... stagnation contributed negatively to the long-term, structural economic problems that showed itself under Prussian hegemony after 1864...

  12. Approximate analytic solutions of stagnation point flow in a porous medium

    Science.gov (United States)

    Kumaran, V.; Tamizharasi, R.; Vajravelu, K.

    2009-06-01

    An efficient and new implicit perturbation technique is used to obtain approximate analytical series solution of Brinkmann equation governing the two-dimensional stagnation point flow in a porous medium. Analytical approximate solution of the classical two-dimensional stagnation point flow is obtained as a limiting case. Also, it is shown that the obtained higher order series solutions agree well with the computed numerical solutions.

  13. Performance and Mechanical Tolerances Achieved with a Full Size Prototype of a CMS Barrel Muon Drift Tubes Chamber

    CERN Document Server

    Bethke, Siegfried; Benettoni, Massimo; Benvenuti, Alberto; Berdugo, Javier; Cerrada, Marcos; Colino, Nicanor; Conti, Enrico; Dallavalle, Gaetano-Marco; Daniel, Manuel; De Giorgi, Marco; De Min, Alberto; Dosselli, Umberto; Fanin, Claudio; Fouz-Iglesias, M C; Gasparini, Fabrizio; Gasparini, Ugo; Giantin, R; Grandi, Claudio; Guaita, Paola; Guerzoni, Marco; Ladrón de Guevara, Pedro; Lippi, Ivano; Marcellini, Stefano; Martinelli, Roberto; Meneguzzo, Anna Teresa; Mocholí-Mocholí, J; Montanari, Alessandro; Montanari, Christian; Navarria, Francesco; Odorici, Fabrizio; Reithler, Hans; Romero, Luciano; Rossi, Antonio; Rovelli, Tiziano; Schwarthoff, Hubert; Sondermann, Volker; Tano, Valeria; Teykal, Helmut; Tutas, Joerg; Van den Hirtz, J; Wagner, H; Wegner, Martin; Willmott, Carlos

    1998-01-01

    The barrel muon chambers of the CMS experiment are made assembling 3 independent modules ( SuperLayers) which together measure the impact point and the angles theta and phi. Each SuperLayer consists of four layers of rectangular Drift Tubes. MB96 is a full size prototype of the smallest CMS Barrel Muon Chamber ( MB1) built in early 1997 at the Legnaro INFN laboratory and tested in summer 1997 at the CERN CMS test beam facility. The performance of the prototype and the mechanical tolerances achieved in the construction are presented.

  14. Evidence-based surgical training in orthopaedics: how many arthroscopies of the knee are needed to achieve consultant level performance?

    Science.gov (United States)

    Price, A J; Erturan, G; Akhtar, K; Judge, A; Alvand, A; Rees, J L

    2015-10-01

    Despite being one of the most common orthopaedic operations, it is still not known how many arthroscopies of the knee must be performed during training in order to develop the skills required to become a Consultant. A total of 54 subjects were divided into five groups according to clinical experience: Novices (n = 10), Junior trainees (n = 10), Registrars (n = 18), Fellows (n = 10) and Consultants (n = 6). After viewing an instructional presentation, each subject performed a simple diagnostic arthroscopy of the knee on a simulator with visualisation and probing of ten anatomical landmarks. Performance was assessed using a validated global rating scale (GRS). Comparisons were made against clinical experience measured by the number of arthroscopies which had been undertaken, and ROC curve analysis was used to determine the number of procedures needed to perform at the level of the Consultants. There were marked differences between the groups. There was significant improvement in performance with increasing experience (p < 0.05). ROC curve analysis identified that approximately 170 procedures were required to achieve the level of skills of a Consultant. We suggest that this approach to identify what represents the level of surgical skills of a Consultant should be used more widely so that standards of training are maintained through the development of an evidenced-based curriculum. ©2015 The British Editorial Society of Bone & Joint Surgery.

  15. How many trials are needed to achieve performance stability of the Timed Up & Go test in patients with hip fracture?

    Science.gov (United States)

    Kristensen, Morten T; Ekdahl, Charlotte; Kehlet, Henrik; Bandholm, Thomas

    2010-06-01

    To examine the number of trials needed to achieve performance stability of the Timed Up & Go (TUG) test using a standardized walking aid in patients with hip fracture who are allowed full weight bearing (FWB). Prospective methodologic study. An acute 14-bed orthopedic hip fracture unit. Patients (N=122; 89 women, 33 men) with hip fracture with a median age (25%-75%, quartiles) of 80 (67-85) years performed the TUG on hospital discharge to their own home (n=115) or further inpatient rehabilitation (n=7). Not applicable. After a demonstration by a physical therapist how to perform the TUG with a standardized walking aid (a 4-wheeled rollator), the patients performed 6 timed TUG trials with up to 1-minute seated rest intervals. The participants were given a few minutes to familiarize with the rollator before commencing the timed trials. Repeated-measures analysis of variance (ANOVA) with Bonferroni corrections were used to examine the number of trials needed to ensure statistically stable TUG scores. A total of 106 (87%) patients performed all 6 TUG trials, while 120 patients performed a minimum of 3 timed trials. Repeated-measures ANOVAs of both groups showed that TUG scores improved significantly (Pup to and including the third TUG trial. These results suggest that the original TUG manual, described as 1 practice trial followed by 1 timed trial, needs modification when used in patients with hip fracture who are allowed FWB. The best (fastest) of 3 timed TUG trials performed with a standardized walking aid is recommended. Copyright 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  16. Quality of Education Predicts Performance on the Wide Range Achievement Test-4th Edition Word Reading Subtest

    Science.gov (United States)

    Sayegh, Philip; Arentoft, Alyssa; Thaler, Nicholas S.; Dean, Andy C.; Thames, April D.

    2014-01-01

    The current study examined whether self-rated education quality predicts Wide Range Achievement Test-4th Edition (WRAT-4) Word Reading subtest and neurocognitive performance, and aimed to establish this subtest's construct validity as an educational quality measure. In a community-based adult sample (N = 106), we tested whether education quality both increased the prediction of Word Reading scores beyond demographic variables and predicted global neurocognitive functioning after adjusting for WRAT-4. As expected, race/ethnicity and education predicted WRAT-4 reading performance. Hierarchical regression revealed that when including education quality, the amount of WRAT-4's explained variance increased significantly, with race/ethnicity and both education quality and years as significant predictors. Finally, WRAT-4 scores, but not education quality, predicted neurocognitive performance. Results support WRAT-4 Word Reading as a valid proxy measure for education quality and a key predictor of neurocognitive performance. Future research should examine these findings in larger, more diverse samples to determine their robust nature. PMID:25404004

  17. Case study: Comparison of motivation for achieving higher performance between self-directed and manager-directed aerospace engineering teams

    Science.gov (United States)

    Erlick, Katherine

    "The stereotype of engineers is that they are not people oriented; the stereotype implies that engineers would not work well in teams---that their task emphasis is a solo venture and does not encourage social aspects of collaboration" (Miner & Beyerlein, 1999, p. 16). The problem is determining the best method of providing a motivating environment where design engineers may contribute within a team in order to achieve higher performance in the organization. Theoretically, self-directed work teams perform at higher levels. But, allowing a design engineer to contribute to the team while still maintaining his or her anonymity is the key to success. Therefore, a motivating environment must be established to encourage greater self-actualization in design engineers. The purpose of this study is to determine the favorable motivational environment for design engineers and describe the comparison between two aerospace design-engineering teams: one self-directed and the other manager directed. Following the comparison, this study identified whether self-direction or manager-direction provides the favorable motivational environment for operating as a team in pursuit of achieving higher performance. The methodology used in this research was the case study focusing on the team's levels of job satisfaction and potential for higher performance. The collection of data came from three sources, (a) surveys, (b) researcher observer journal and (c) collection of artifacts. The surveys provided information regarding personal behavior characteristics, potentiality for higher performance and motivational attributes. The researcher journal provided information regarding team dynamics, individual interaction, conflict and conflict resolution. The milestone for performance was based on the collection of artifacts from the two teams. The findings from this study illustrated that whether the team was manager-directed or self-directed does not appear to influence the needs and wants of the

  18. Measurements of the Influence of Integral Length Scale on Stagnation Region Heat Transfer

    Science.gov (United States)

    Vanfossen, G. James; Ching, Chang Y.

    1994-01-01

    The purpose was twofold: first, to determine if a length scale existed that would cause the greatest augmentation in stagnation region heat transfer for a given turbulence intensity and second, to develop a prediction tool for stagnation heat transfer in the presence of free stream turbulence. Toward this end, a model with a circular leading edge was fabricated with heat transfer gages in the stagnation region. The model was qualified in a low turbulence wind tunnel by comparing measurements with Frossling's solution for stagnation region heat transfer in a laminar free stream. Five turbulence generating grids were fabricated; four were square mesh, biplane grids made from square bars. Each had identical mesh to bar width ratio but different bar widths. The fifth grid was an array of fine parallel wires that were perpendicular to the axis of the cylindrical leading edge. Turbulence intensity and integral length scale were measured as a function of distance from the grids. Stagnation region heat transfer was measured at various distances downstream of each grid. Data were taken at cylinder Reynolds numbers ranging from 42,000 to 193,000. Turbulence intensities were in the range 1.1 to 15.9 percent while the ratio of integral length scale to cylinder diameter ranged from 0.05 to 0.30. Stagnation region heat transfer augmentation increased with decreasing length scale. An optimum scale was not found. A correlation was developed that fit heat transfer data for the square bar grids to within +4 percent. The data from the array of wires were not predicted by the correlation; augmentation was higher for this case indicating that the degree of isotropy in the turbulent flow field has a large effect on stagnation heat transfer. The data of other researchers are also compared with the correlation.

  19. Experimental comparison of two hot-wire techniques for resolution of turbulent mass flux and local stagnation temperature in supersonic flow

    Science.gov (United States)

    Walker, D. A.; Ng, W. F.; Walker, M. D.

    1988-01-01

    The performance of two constant-temperature normal hot-wire techniques in a supersonic flow is examined. The first technique uses a single-wire and rapid scanning of multiple overheat ratios. Time averages of the signals at all overheats are used to separate the mean and rms mass flux, stagnation temperature and their cross-correlation. The second technique uses a dual-wire probe with each wire operating at different overheat ratios, giving instantaneous mass flux and stagnation temperature. Preliminary results indicate that the separation distance (0.18 mm) between the two hot wires in the dual-wire probe does not introduce significant error. However, the rms mass flux inferred from the dual-wire technique is a factor of two higher than that from the single-wire technique.

  20. Functional Organosulfide Electrolyte Promotes an Alternate Reaction Pathway to Achieve High Performance in Lithium-Sulfur Batteries.

    Science.gov (United States)

    Chen, Shuru; Dai, Fang; Gordin, Mikhail L; Yu, Zhaoxin; Gao, Yue; Song, Jiangxuan; Wang, Donghai

    2016-03-18

    Lithium-sulfur (Li-S) batteries have recently received great attention because they promise to provide energy density far beyond current lithium ion batteries. Typically, Li-S batteries operate by conversion of sulfur to reversibly form different soluble lithium polysulfide intermediates and insoluble lithium sulfides through multistep redox reactions. Herein, we report a functional electrolyte system incorporating dimethyl disulfide as a co-solvent that enables a new electrochemical reduction pathway for sulfur cathodes. This pathway uses soluble dimethyl polysulfides and lithium organosulfides as intermediates and products, which can boost cell capacity and lead to improved discharge-charge reversibility and cycling performance of sulfur cathodes. This electrolyte system can potentially enable Li-S batteries to achieve high energy density.

  1. Phenomenological description of grain growth stagnation for nanocrystalline films and powders

    Energy Technology Data Exchange (ETDEWEB)

    Dannenberg, R.; Stach, E.A.; Groza, J.R.

    2000-08-24

    At fixed hold temperatures, grain growth usually stagnates indefinitely after sufficiently long hold times. The change in the growth behavior can be very abrupt, resulting in a sudden plateau in plots of grain size versus time at fixed temperature. Standard grain growth laws do not formally predict the rapid onset of growth stagnation, merely a slow down of grain growth to imperceptible rates. Therefore, the grain size in the plateau regions for long hold times is typically not in agreement with that predicted with kinetic variables derived from the size versus time curves for short hold times where there is pronounced curvature. Standard laws lead to endpoint grain sizes with strong dependences on the hold times. The experimental observation in many cases is a nearly linear temperature dependence that is independent of the hold times after a sufficient duration. Additionally, the growth process may restart from a stagnated state with sufficient temperature increases, where again, the stagnated grain size temperature dependence is linear. For growth laws including size dependent opposing forces, endpoint grain sizes are predicted to be either independent of temperature, or exponentially temperature dependent with thermodynamic reversibility, the latter an impossibility. We derive, heuristically, a stagnation force, phenomenologically incorporating these observations: a near linear temperature dependence of endpoint grain sizes, and irreversible growth. This description reduces to standard laws commonly used for data fitting, and leads to a normal grain size distribution. Other laws are discussed and compared. Fits to size versus time data are successfully made.

  2. Intellectual and non-intellectual determinants of high academic achievement – the contribution of personality traits to the assessment of high performance potential

    Directory of Open Access Journals (Sweden)

    Silvia Schubhart

    2013-09-01

    Full Text Available In this paper a study is presented which tries to explain and predict high academic achievement in children or adolescents on the basis of intellectual and non-intellectual determinants – in this case, performance relevant personality traits as well as the social environment of stimulation. The prognosis of high academic achievement is based on a new diagnostic model, the Viennese Diagnostic Model of High Achievement Potential, which undergoes its first empirical validation here. The results show impressive evidence that performance-relevant personality traits and categories of social environment of stimulation contribute to high academic achievement in children and adolescents of above-average intelligence.

  3. Wage Dispersion, Public Sector Wages and the Stagnating Danish Gender Wage Gap

    DEFF Research Database (Denmark)

    Gupta, Nabanita Datta; Oaxaca, Ronald L.; Smith, Nina

    1998-01-01

    The gender wage gap in Denmark has virtually stagnated since the early 70s. This study examines whether this stagnation is mainly due to a changing wage dispersion or to changing prices on observed and unobserved skills. Since about half the female labour force is employed in the public sector....... These techniques are applied to a sample of Danish wage earners in the period 1983-94. The decomposition results suggest different explanations behind the stagnation of the gender wage gap in the public and private sectors. The development in average public sector wages is calculated assuming observed......, the impact of the changing wage structure between the public and private sectors is investigated. The analysis is based on the Juhn-Murphy-Pierce decomposition applied to a pooled wage regression model. The equivalence between the former and the Oaxaca-Ransom generalized wage decomposition is established...

  4. MHD Stagnation Flow of a Newtonian Fluid towards a Uniformly Heated and Moving Vertical Plate

    Directory of Open Access Journals (Sweden)

    Mehmet Şirin Demir

    2016-01-01

    Full Text Available Stagnation flow of an electrically conducting incompressible viscous fluid towards a moving vertical plate in the presence of a constant magnetic field is investigated. By using the appropriate transformations for the velocity components and temperature, the partial differential equations governing flow and heat transfer are reduced to a set of nonlinear ordinary differential equations. These equations are solved approximately using a numerical technique for the following two problems: (i two-dimensional stagnation-point flow on a moving vertical plate, (ii axisymmetric stagnation-point flow on a moving vertical plate. The effects of non-dimensional parameters on the velocity components, wall shear stresses, temperature and heat transfer are examined carefully.

  5. A strategy for reducing stagnation phase hydrodynamic instability growth in inertial confinement fusion implosions

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D. S.; Robey, H. F.; Smalyuk, V. A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    2015-05-15

    Encouraging progress is being made in demonstrating control of ablation front hydrodynamic instability growth in inertial confinement fusion implosion experiments on the National Ignition Facility [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, and R. Al-Ayat, Phys. Plasmas 16, 041006 (2009)]. Even once ablation front stabilities are controlled, however, instability during the stagnation phase of the implosion can still quench ignition. A scheme is proposed to reduce the growth of stagnation phase instabilities through the reverse of the “adiabat shaping” mechanism proposed to control ablation front growth. Two-dimensional radiation hydrodynamics simulations confirm that improved stagnation phase stability should be possible without compromising fuel compression.

  6. Measurements of the stagnation pressure in the center of a cavitating jet

    Science.gov (United States)

    Nobel, A. J.; Talmon, A. M.

    2012-02-01

    The stagnation pressure at a certain distance from the nozzle is important for the erosion/ cutting capacity of a submerged jet in dredging. The decay of the stagnation pressure with jet distance is well known in the case of non-cavitating jets. It is also known that cavitation causes the rate of decay to decrease. Under conditions of cavitation, a cone of bubbles forms around the jet, which decreases the momentum exchange between the jet and the ambient water and the associated entrainment. Despite the amount of research on cavitating jets, the literature does not provide a description for the entrainment in the case of a cavitating jet. Also, a useful description of the stagnation pressure decay of a cavitating jet is missing. To fill this lacuna, we carried out jet tests at various ambient pressures in both fresh and saline water. We present and analyse the results in this paper.

  7. Moving Model Test of High-Speed Train Aerodynamic Drag Based on Stagnation Pressure Measurements.

    Science.gov (United States)

    Yang, Mingzhi; Du, Juntao; Li, Zhiwei; Huang, Sha; Zhou, Dan

    2017-01-01

    A moving model test method based on stagnation pressure measurements is proposed to measure the train aerodynamic drag coefficient. Because the front tip of a high-speed train has a high pressure area and because a stagnation point occurs in the center of this region, the pressure of the stagnation point is equal to the dynamic pressure of the sensor tube based on the obtained train velocity. The first derivation of the train velocity is taken to calculate the acceleration of the train model ejected by the moving model system without additional power. According to Newton's second law, the aerodynamic drag coefficient can be resolved through many tests at different train speeds selected within a relatively narrow range. Comparisons are conducted with wind tunnel tests and numerical simulations, and good agreement is obtained, with differences of less than 6.1%. Therefore, the moving model test method proposed in this paper is feasible and reliable.

  8. Influence of Turbulence Parameters, Reynolds Number, and Body Shape on Stagnation-Region Heat Transfer

    Science.gov (United States)

    Vanfossen, G. James; Simoneau, Robert J.; Ching, Chan Y.

    1994-01-01

    The purpose of the present work was threefold: (1) to determine if a free-stream turbulence length scale existed that would cause the greatest augmentation in stagnation-region heat transfer over laminar levels; (2) to investigate the effect of velocity gradient on stagnation-region heat transfer augmentation by free-stream turbulence; and (3) to develop a prediction tool for stagnation heat transfer in the presence of free-stream turbulence. Heat transfer was measured in the stagnation region of four models with elliptical leading edges that had ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Five turbulence-generating grids were fabricated; four were square mesh, biplane grids made from square bars. The fifth grid was an array of fine parallel wires that were perpendicular to the model spanwise direction. Heat transfer data were taken at Reynolds numbers ranging from 37 000 to 228 000. Turbulence intensities were in the range of 1.1 to 15.9% while the ratio of integral length scale to leading-edge diameter ranged from 0.05 to 0.30. Stagnation-point velocity gradient was varied by nearly 50%. Stagnation-region heat transfer augmentation was found to increase with decreasing length scale but no optimum length scale was found. Heat transfer augmentation due to turbulence was found to be unaffected by the velocity gradient near the leading edge. A correlation was developed that fit heat transfer data for the square-bar grids to within +/- 4%.

  9. Heat transfer in stagnation-point flow towards a stretching sheet

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, T. Ray; Gupta, A.S. [Department of Mathematics, Indian Institute of Technology, Kharagpur (India)

    2002-06-01

    Steady two-dimensional stagnation-point flow of an incompressible viscous fluid over a flat deformable sheet is investigated when the sheet is stretched in its own plane with a velocity proportional to the distance from the stagnation-point. It is shown that for a fluid of small kinematic viscosity, a boundary layer is formed when the stretching velocity is less than the free stream velocity and an inverted boundary layer is formed when the stretching velocity exceeds the free stream velocity. Temperature distribution in the boundary layer is found when the surface is held at constant temperature and surface heat flux is determined. (orig.)

  10. Large Vortex in Front Stagnation Region of a Square Plate Induced by a Fine Interference Wire

    Institute of Scientific and Technical Information of China (English)

    连淇祥; 苏宗周

    1994-01-01

    Using hydrogen bubble technique, the great change in flow field caused by weak interference in the stagnation region has been observed. When a fine interference wire was set in the upstream of a square plate, the wake of the wire invoked a large counter rotating vortex pair in the front stagnation region of the square plate. This large vortex pair and the reverse flow region might occupy a region larger than half part of the model, with a size over a 100 times greater than the diameter of the interference wire. The formation and development process of the large vortex pair are investigated in this paper.

  11. Gender Differences in Achievement Goals and Performances in English Language and Mathematics of Senior Secondary Schools Students in Borno State, Nigeria

    Science.gov (United States)

    Musa, Alice K. J.; Dauda, Bala; Umar, Mohammad A.

    2016-01-01

    The paper investigated gender difference in achievement goals and performance in English Language and Mathematics of senior secondary schools students in Borno State, Nigeria. The study specifically sought to determine gender differences in students' academic performances in English Language, Mathematics and overall academic performance as well as…

  12. Influence of equipment and settings on myocardial performance index repeatability and definition of settings to achieve optimal reproducibility.

    Science.gov (United States)

    Lobmaier, S M; Cruz-Lemini, M; Valenzuela-Alcaraz, B; Ortiz, J U; Martinez, J M; Gratacos, E; Crispi, F

    2014-06-01

    To compare left myocardial performance index (MPI) values and reproducibility using different settings and ultrasound equipment in order to standardize optimal machine settings. Left MPI was prospectively evaluated by one observer performing conventional Doppler in 62 fetuses (28-36 weeks of gestational age) using different settings (changing sweep speed, gain and wall motion filter (WMF)) and two different ultrasound devices (Siemens Antares, Siemens; Voluson 730 Expert, GE Medical Systems). Intraclass coefficients of agreement (ICCs) were calculated using Bland-Altman analysis. Using baseline settings on the Siemens, mean (SD) MPI was 0.44 (0.05) with an ICC of 0.81. Decreasing the sweep speed resulted in decreasing average MPI values (0.43) and decreasing ICC (0.61). Lowering gain also influenced average MPI values (0.46) and ICC (0.76). Raising gain resulted in similar MPI values (0.45) with better ICC (0.90) compared with baseline settings. Raising wall motion filter (WMF) provided the best ICC (0.94) compared with the other settings. Changing the ultrasound equipment resulted in an ICC of 0.64. The optimal settings to achieve the highest reproducibility in measurement of MPI were sweep speed 8, gain 60 dB and WMF 281 Hz for Siemens Antares and sweep speed 5, gain -10 dB and WMF 210 Hz for Voluson 730 Expert. Changing ultrasound settings or equipment may affect the calculation and repeatability of measurement of MPI values. Strict standardization of methods decreases the variability of this parameter for fetal cardiac function assessment. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

  13. DTC-SVM Based on PI Torque and PI Flux Controllers to Achieve High Performance of Induction Motor

    Directory of Open Access Journals (Sweden)

    Hassan Farhan Rashag

    2014-01-01

    Full Text Available The fundamental idea of direct torque control of induction machines is investigated in order to emphasize the property produced by a given voltage vector on stator flux and torque variations. The proposed control system is based on Space Vector Modulation (SVM of electrical machines, Improvement model reference adaptive system, real time of stator resistance and estimation of stator flux. The purpose of this control is to minimize electromagnetic torque and flux ripple and minimizing distortion of stator current. In this proposed method, PI torque and PI flux controller are designed to achieve estimated torque and flux with good tracking and fast response with reference torque and there is no steady state error. In addition, design of PI torque and PI flux controller are used to optimize voltages in d-q reference frame that applied to SVM. The simulation Results of proposed DTC-SVM have complete excellent performance in steady and transient states as compared with classical DTC-SVM.

  14. Economic stagnation postponed: background of the 2008 financial-economic crisis in the European Union and the United States

    NARCIS (Netherlands)

    Reuten, G.

    2011-01-01

    The significant increase since the early 1980s in the share of income accruing to capital (rather than labor), in both the United States and the European Union, created the potential for economic stagnation. Stagnation was postponed, however, by the development of the banking sector in these countri

  15. Invalidating stagnation theory for family owned businesses : comparing family-to-family and third party ownership transfers

    NARCIS (Netherlands)

    Heaver, Roger; Ibrahimovic, Alija; Teeffelen, Lex van

    2015-01-01

    Miller, Le Breton-Miller and Scholnick (2008) summarize and discuss two major perspectives constructed from the literature on family owned businesses (FOBs): stewardship and stagnation theory. In this paper the stagnation theory is being put to the test on Dutch small/medium enterprises (SMEs). Acco

  16. Craft-Joule Project: Stagnation proof transparently insulated flat plate solar collector (static)

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, A; Cadafalch, J; Perez-Segarra, C.D. [Universitat Politecnica de Catalunya, Barcelona (Spain)] (and others)

    2000-07-01

    The STATIC (STAgnation proof Transparently Insulated flat plate Solar Collector) project is a Craft-Joule Project within the framework of the Non Nuclear Energy Programme Joule III coordinated by the Centre Technologic de Transferencia de Calor (CTTC). The core group of SMEs involved in the project has its main economical activity in the field of solar thermal systems at low temperature level (domestic hot water, solar heating, etc.). Beyond this, a large application potential exists for solar heating at medium temperature level (from 80 to 160 Celsius degrees) : industrial process heat, solar cooling and air conditioning, solar drying , distillation and desalination. Three of the four SME proposers are located in Southern Europe and in the Caribean, where a continuos increase of the demand for air conditioning and cooling has been demonstrated in the last years. The recent development of flat plate solar collectors with honeycomb-type transparent insulation cover has shown that this type of collectors can become a low cost alternative to evacuated tube and high concentrating CPC collectors in the medium temperature range from 80 to 160 Celsius degrees. With the expected reduction of collector cost, that forms 30%-50% of total system cost, a decisive break-through of solar thermal systems using heat in the medium temperature range can be achieved. The feasibility and good performance of these solar collectors has been proved in several prototypes. Nevertheless, up to now no commercial products are available. In order to reach this, the following developments of new concepts are necessary and are being carried out within this project: solution of the problem of overheating: development of collector versions for different working temperatures: optimization of the design with the support of high level numerical simulation. Several prototypes of the new solar collectors are being tested. System tests will also be carried or for two test arrays of optimized collector

  17. Performance Assessment of High and Low Income Families through "Online RAW Achievement Battery Test" of Primary Grade Students

    Science.gov (United States)

    Ahmed, Tamim; Hanif, Maria

    2016-01-01

    This study is intended to investigate student's achievement capability among two families i.e. Low and High income families and designed for primary level learners. A Reading, Arithmetic and Writing (RAW) Achievement test that was developed as a part of another research study (Tamim Ahmed Khan, 2015) was adopted for this study. Both English medium…

  18. A Multi-Institutional Study of the Relationship between High School Mathematics Achievement and Performance in Introductory College Statistics

    Science.gov (United States)

    Dupuis, Danielle N.; Medhanie, Amanuel; Harwell, Michael; LeBeau, Brandon; Monson, Debra; Post, Thomas R.

    2012-01-01

    In this study we examined the effects of prior mathematics achievement and completion of a commercially developed, National Science Foundation-funded, or University of Chicago School Mathematics Project high school mathematics curriculum on achievement in students' first college statistics course. Specifically, we examined the relationship between…

  19. A Multi-Institutional Study of the Relationship between High School Mathematics Achievement and Performance in Introductory College Statistics

    Science.gov (United States)

    Dupuis, Danielle N.; Medhanie, Amanuel; Harwell, Michael; LeBeau, Brandon; Monson, Debra; Post, Thomas R.

    2012-01-01

    In this study we examined the effects of prior mathematics achievement and completion of a commercially developed, National Science Foundation-funded, or University of Chicago School Mathematics Project high school mathematics curriculum on achievement in students' first college statistics course. Specifically, we examined the relationship between…

  20. Axisymmetric rotational stagnation-point flow impinging on a rotating disk

    Science.gov (United States)

    Weidman, Patrick

    2015-12-01

    Agrawal's (Q J Mech Appl Math, 10:42-44, 1957) stagnation-point flow problem is extended to flow impingement normal to a uniformly rotating disk. This is the analog of the extension of Homann's (Z Angew Math Mech (ZAMM), 16:153-164, 1936) stagnation flow when impinging on a rotating disk as reported by Hannah (Rep Mem Aerosp Res Coun Lond 2772, 1947). While both oncoming stagnation flows are axisymmetric, in the far field Homann's stagnation flow is irrotational while Agrawal's is rotational. A similarity reduction of the Navier-Stokes equations yields a pair of coupled ordinary differential equations governed by a dimensionless rotation rate σ. Integrations were carried out up to σ = 30 beyond which the equations become stiff and solution independence of integration length cannot be ensured. Results for the radial and azimuthal shear stresses are presented along with the strength of the flow induced into the boundary layer and the thickness of the azimuthal flow boundary layer. Analytic results found at σ = 0 are shown to be in excellent agreement with the numerical calculations. Sample velocity profiles for the radial and azimuthal flows are presented.

  1. Micropolar boundary layer flow at a stagnation point on a moving wall with suction and injection

    Science.gov (United States)

    Hassanien, I. A.; Hady, F. M.

    1988-10-01

    The flow of a micropolar fluid at a two-dimensional stagnation point on a moving wall with suction and injection is studied. Numerical computations were carried out on a VME-2955 computer. The effects of the suction/injection parameter and dimensionless material parameters are discussed.

  2. Stagnation-point flow of the Walters' B' fluid with slip

    Directory of Open Access Journals (Sweden)

    F. Labropulu

    2004-01-01

    Full Text Available The steady two-dimensional stagnation point flow of a non-Newtonian Walters' B' fluid with slip is studied. The fluid impinges on the wall either orthogonally or obliquely. A finite difference technique is employed to obtain solutions.

  3. Augmentation of Stagnation Region Heat Transfer Due to Turbulence from a DLN Can Combustor

    Science.gov (United States)

    VanFossen, G. James; Bunker, Ronald S.

    2001-01-01

    Heat transfer measurements have been made in the stagnation region of a flat plate with a circular leading edge. Electrically heated aluminum strips placed symmetrically about the leading edge stagnation region were used to measure spanwise-averaged heat transfer coefficients. The maximum Reynolds number obtained, based on leading edge diameter, was about 100,000. The model was immersed in the flow field downstream of an approximately half-scale model of a can-type combustor from a low NO(x), ground-based power-generating turbine. The tests were conducted with room temperature air; no fuel was added. Room air flowed into the combustor through six vane-type fuel/air swirlers. The combustor can contained no dilution holes. The fuel/air swirlers all swirled the incoming airflow in a counterclockwise direction (facing downstream). A five-hole probe flow field survey in the plane of the model stagnation point showed the flow was one big vortex with flow angles up to 36 deg at the outer edges of the rectangular test section. Hot-wire measurements showed test section flow had very high levels of turbulence, around 28.5%, and had a relatively large axial-length scale-to-leading edge diameter ratio of 0.5. X-wire measurements showed the turbulence to be nearly isotropic. Stagnation heat transfer augmentation over laminar levels was around 77% and was about 14% higher than predicted by a previously developed correlation for isotropic grid-generated turbulence.

  4. On the Analytical Solution of Non-Orthogonal Stagnation Point Flow towards a Stretching Sheet

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Bagheri, G. H.; Barari, Amin

    2011-01-01

    An analytical solution for non-orthogonal stagnation point for the steady flow of a viscous and incompressible fluid is presented. The governing nonlinear partial differential equations for the flow field are reduced to ordinary differential equations by using similarity transformations existed i...

  5. Prediction and experimental validation of stagnation temperature attained by a solar cooker of hot box type

    Energy Technology Data Exchange (ETDEWEB)

    Narasimha Rao, A. V; Srikrishna, D. V. N [Warangal (India)

    2000-07-01

    A hot box type solar cooker, having double glass covers and a plane mirror reflector, is tested for stagnation temperature. A computer code is developed based on the analytical model proposed by Vaishya et. al. The global and beam components of solar radiation measured at Warangal are made use to predict the stagnation temperature of the cooker. The observed values of stagnation temperature at Warangal are compared with those of predicted values. A good agreement of the measured and observed values of the stagnation temperature is observed during the afternoon period. The lag in the observed values during the forenoon may be due to thermal inertia of the cooker. [Spanish] Se probo una estufa solar de tipo caja caliente con cubiertas dobles de vidrio y un espejo reflector plano para medir la temperatura de estancamiento. Se desarrollo un codigo de computacion basado en el modelo analitico propuesto por Vaishya et. al. Los componentes de la radiacion solar globales y de rayo medidos en Warangal se usan para predecir la temperatura de estancamiento de la estufa. Los valores observados de la temperatura de estancamiento en Warangal se comparan con los valores predichos. Se aprecia una buena concidencia de los valores medidos y observados de la temperatura de estancamiento durante el periodo de la tarde. El retraso de los valores observados durante la manana puede ser debido a la inercia termica de la estufa.

  6. What Explains the Stagnation of Female Labor Force Participation in Urban India?

    NARCIS (Netherlands)

    Klasen, S.; Pieters, J.

    2015-01-01

    Female labor force participation rates in urban India between 1987 and 2011 are surprisingly low and have stagnated since the late 1980s. Despite rising growth, fertility decline, and rising wage and education levels, married women's labor force participation hovered around 18 percent. Analysis of f

  7. Diagnosing the Stagnation Conditions of MagLIF Implosions Using High-Resolution Spectroscopy

    Science.gov (United States)

    Harding, Eric

    2016-10-01

    An inertial fusion concept known as Magnetized Liner Inertial Fusion (MagLIF) is currently being pursued on the Z-machine at Sandia National Laboratory. Electrical current from the Z-machine is directly coupled onto the outside surface of a beryllium tube known as a ``liner'' causing it to implode. The liner contains gaseous deuterium (D2) fuel, which is pre-magnetized, pre-heated, and then compressed by the imploding walls of the liner. Target implosions of this type have produced thermonuclear plasmas that generated 2e12 DD neutrons [M.R. Gomez et al., PRL 113, 155003 (2014)]. For the first time we have accurately measured the space-dependent, fuel conditions at the time of stagnation. In addition, the state of the compressed Be liner was determined. This was accomplished by the simultaneous use of high-resolution, x-ray spectroscopic and imaging diagnostics. These new measurements relied on the observation of K-shell spectra emitted by microscopic iron and nickel impurities that naturally occur in the Be. The measurements currently indicate that the non-uniformity of the x-ray emission from the fuel is due to variations in the fuel conditions. Ultimately, the data provides critical insight into the performance of the MagLIF target and will further enable us to enhance the target design. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract No. DE-AC04-94AL85000.

  8. Stagnating crop yields: An overlooked risk for the carbon balance of agricultural soils?

    Science.gov (United States)

    Wiesmeier, Martin; Hübner, Rico; Kögel-Knabner, Ingrid

    2015-12-01

    The carbon (C) balance of agricultural soils may be largely affected by climate change. Increasing temperatures are discussed to cause a loss of soil organic carbon (SOC) due to enhanced decomposition of soil organic matter, which has a high intrinsic temperature sensitivity. On the other hand, several modeling studies assumed that potential SOC losses would be compensated or even outperformed by an increased C input by crop residues into agricultural soils. This assumption was based on a predicted general increase of net primary productivity (NPP) as a result of the CO2 fertilization effect and prolonged growing seasons. However, it is questionable if the crop C input into agricultural soils can be derived from NPP predictions of vegetation models. The C input in European croplands is largely controlled by the agricultural management and was strongly related to the development of crop yields in the last decades. Thus, a glance at past yield development will probably be more instructive for future estimations of the C input than previous modeling approaches based on NPP predictions. An analysis of European yield statistics indicated that yields of wheat, barley and maize are stagnating in Central and Northern Europe since the 1990s. The stagnation of crop yields can probably be related to a fundamental change of the agricultural management and to climate change effects. It is assumed that the soil C input is concurrently stagnating which would necessarily lead to a decrease of agricultural SOC stocks in the long-term given a constant temperature increase. Remarkably, for almost all European countries that are faced with yield stagnation indications for agricultural SOC decreases were already found. Potentially adverse effects of yield stagnation on the C balance of croplands call for an interdisciplinary investigation of its causes and a comprehensive monitoring of SOC stocks in agricultural soils of Europe.

  9. Effects of inhomogeneity at stagnation in 3D simulations of ICF implosions

    Science.gov (United States)

    Appelbe, Brian

    2016-10-01

    The stagnation phase of an ICF implosion is characterized by a hotspot and dense fuel layer that are spatially and temporally inhomogeneous. Perturbation growth during the implosion results in significant asymmetry at stagnation while the hotspot size, density and temperature change rapidly, even in non-igniting capsules. Diagnosing these inhomogeneities is necessary to increase yield in ICF experiments. In this work, 3D radiation hydrodynamic simulations of perturbed indirect drive ICF capsules are carried out using the CHIMERA code. During the stagnation phase a suite of novel and computationally efficient simulation tools are used to produce synthetic time-resolved neutron spectra and images. These tools allow a detailed study of the effects of hotspot inhomogeneities on diagnostic signals. Results show that the burn-averaged ion temperature drops rapidly during thermonuclear burn as the hotspot evolves from a localised, shock-heated region to a more massive, non-uniform plasma. Primary DD and DT neutron spectra show that there is significant residual bulk fluid motion at stagnation, complicating the measurement of ion temperature. Different perturbation modes cause different levels of anisotropic spectra shifts and broadening. However, in all cases the discrepancies between the DD and DT spectra are a reliable indicator of residual motion at stagnation. The simulations are used to examine the relationship between neutron scattering and areal density (ρR). Three measures of areal density are simulated: downscattered neutron ratio, attenuated primary neutron yield and nT backscatter edge. Each of these diagnoses the magnitude and anisotropy of the ρR with varying success, with accuracy decreasing for higher mode perturbations. Contributions to the neutron energy spectra from T +T reactions, secondary DT reactions and deuteron break-up are also evaluated.

  10. Quantifying Faculty Productivity in Japan: Development and Application of the Achievement-Motivated Key Performance Indicator. Research & Occasional Paper Series: CSHE.8.16

    Science.gov (United States)

    Aida, Misako; Watanabe, Satoshi P.

    2016-01-01

    Universities throughout the world are trending toward more performance based methods to capture their strengths, weaknesses and productivity. Hiroshima University has developed an integrated objective measure for quantifying multifaceted faculty activities, namely the "Achievement-Motivated Key Performance Indicator" (A-KPI), in order to…

  11. A meta-analytic review of the approach-avoidance achievement goals and performance relationships in the sport psychology literature

    Directory of Open Access Journals (Sweden)

    Marc Lochbaum

    2015-06-01

    Conclusion: The performance goal contrast holds value for sport performance research. Contrary to approach-avoidance predictions, the mastery-approach goal and performance effect size was significant and of equal magnitude as the performance approach goal and performance effect size. Thus, future research should closely test the efficacy of both the mastery- and performance contrasts in impacting performance of sport tasks. Last, the significant effect sizes reported in this review are in stark contrast to contemporary meta-analytic findings in education. Differences in the approach-avoidance goals in sport and education relative to performance should be researched further.

  12. The importance of economic structure evolution in achieving performance: From agrarian economy to competitiveness in Romanian economy

    Directory of Open Access Journals (Sweden)

    Andrei Vasile Jean

    2014-01-01

    Full Text Available In terms of more increased integration and globalization of markets, risk diversification and exposure to external economic factors disturbing the structure of the national economy acquires a major role in alleviating and absorbing adverse effects on national economies are exposed. Starting from the reality that reducing disparities and achieving convergence criteria cannot be achieved except through the perspective of economic structures, the main objective of this research is the analysis of the importance of the economic structure in achieving functional requirements and competitive market economy, in the process of transition agrarian economy to a market economy in Romania, highlighting the main changes and effects that occurred in the past twenty-three years in the national economy, with a closer approach on agricultural structures.

  13. Fifteen Years of Collaborative Innovation and Achievement: NASA Nebraska Space Grant Consortium 15-Year Program Performance and Results Report

    Science.gov (United States)

    Schaaf, Michaela M.; Bowen, Brent D.; Fink, Mary M.; Nickerson, Jocelyn S.; Avery, Shelly; Carstenson, Larry; Dugan, James; Farritor, Shane; Joyce, James; Rebrovich, Barb

    2003-01-01

    Condensing five years of significant work into a brief narrative fitting PPR requirements gave the affiliates of the Nebraska Space Grant a valuable chance for reflection. Achievements of Space Grant in Nebraska were judiciously chosen for this document that best illustrate the resultant synergism of this consortium, keeping in mind that these examples are only a representation of greater activity throughout the state. Following are highlights of many of the finer and personal achievements for Nebraska Space Grant. The Consortium welcomes inquiries to elaborate on any of these accomplishments.

  14. Dual solutions of stagnation point flow and heat transfer of Maxwell fluid over a permeable stretching/shrinking sheet in the presence of nanoparticles

    Science.gov (United States)

    Jusoh, Rahimah; Nazar, Roslinda

    2017-08-01

    Numerical investigation for stagnation point flow and heat transfer of Maxwell fluid over a stretching/shrinking sheet in the presence of nanoparticles has been performed. A similarity transformation has been used to transform the governing partial differential equations to a system of nonlinear ordinary differential equations. The transformed equations are solved numerically using the built in bvp4c function in Matlab. Graphical results are plotted for the local Nusselt number and the local Sherwood number for various values of the emerging parameters. Final conclusion has been drawn on the basis of both numerical and graphical results. Dual solutions exist and the first solution is found to be stable.

  15. Staying with the Text: The Contribution of Gender, Achievement Orientations, and Interest to Students' Performance on a Literacy Task

    Science.gov (United States)

    Graham, Jedda; Tisher, Ruth; Ainley, Mary; Kennedy, Gregor

    2008-01-01

    This study addresses concerns about boys' underperformance on literacy tasks compared to girls, by investigating male and females students' responses to narrative texts. Participants were 142 Grade 9 and 10 students. Achievement orientations, including goals, self-efficacy, and self-handicapping, were measured and approach and avoidance factors…

  16. Academic Achievement and Personality Traits of Faculty Members of Indian Agricultural Universities: Their Effect on Teaching and Research Performance

    Science.gov (United States)

    Ramesh, P.; Reddy, K. M.; Rao, R. V. S.; Dhandapani, A.; Siva, G. Samba; Ramakrishna, A.

    2017-01-01

    Purpose: The present study was undertaken to assess academic achievement, teaching aptitude and research attitude of Indian agricultural universities' faculty, to predict indicators for successful teachers and researchers, and thereby enhancing the quality of higher agricultural education. Methodology: Five hundred faculty members were selected to…

  17. A Study on the Impact of Military Parent Deployment on Student Performance; Academic Achievement, Absenteeism, Discipline, and Counselor Visits

    Science.gov (United States)

    Arnold, Hilda

    2013-01-01

    The purpose of the study was to determine if parents' military deployment had an impact on the academic achievement of their children. The study examined if there were a parallel between parental military deployment and absenteeism, parental deployment and discipline, and parental deployment and counselor visits. The study also examined if…

  18. Students' Accounts of School-Performance Stress: A Qualitative Analysis of a High-Achieving Setting in Stockholm, Sweden

    Science.gov (United States)

    Låftman, Sara Brolin; Almquist, Ylva B.; Östberg, Viveca

    2013-01-01

    The aim of the study is to examine students' experiences of school performance as a stressor. Accounts of school-performance stress at both the individual level and in relation to group mechanisms are studied through qualitative interviews with eighth-grade students in a high-performing school in Stockholm, Sweden (n = 49). Using qualitative…

  19. Student Achievement Gaps in High-Performing Schools: Differences as a Function of the Professional Staff as a Learning Community.

    Science.gov (United States)

    Cowley, Kimberly S.; Meehan, Merrill L.

    This study investigated differences among professional staff members' commitment to continuous learning and improvement in high-performing schools differentiated by student academic performance and disaggregated by race and socioeconomic status. A total of 48 high-performing schools were identified by Kentucky Department of Education staff based…

  20. Modeling of Aerobrake Ballute Stagnation Point Temperature and Heat Transfer to Inflation Gas

    Science.gov (United States)

    Bahrami, Parviz A.

    2012-01-01

    A trailing Ballute drag device concept for spacecraft aerocapture is considered. A thermal model for calculation of the Ballute membrane temperature and the inflation gas temperature is developed. An algorithm capturing the most salient features of the concept is implemented. In conjunction with the thermal model, trajectory calculations for two candidate missions, Titan Explorer and Neptune Orbiter missions, are used to estimate the stagnation point temperature and the inflation gas temperature. Radiation from both sides of the membrane at the stagnation point and conduction to the inflating gas is included. The results showed that the radiation from the membrane and to a much lesser extent conduction to the inflating gas, are likely to be the controlling heat transfer mechanisms and that the increase in gas temperature due to aerodynamic heating is of secondary importance.

  1. Unsteady heat transfer in non-axisymmetric Homann stagnation-point flows

    Science.gov (United States)

    Mahapatra, T. R.; Sidui, S.

    2017-04-01

    An analysis is carried out to study the unsteady non-axisymmetric Homann's stagnation-point flow and heat transfer of an incompressible viscous fluid over a rigid plate in the presence of time-dependent free stream. The temperature of the plate is assumed to be higher than the ambient fluid temperature. Using similarity variables, the governing partial differential equations are transformed into nonlinear ordinary differential equations. These equations are then solved numerically using fourth-order Runge-Kutta method with shooting technique. The effects of the shear-to-strain rate ratio parameter γ (γ =b/a where a and b are the strain rate and shear rate of the stagnation-point flow, respectively) and the unsteadiness parameter λ on wall shear stress parameters, dimensionless velocities, rate of heat transfer at the wall and dimensionless temperature are analysed. It is found that the large-γ asymptotes do not depend on the parameter λ.

  2. Buoyancy effects on the 3D MHD stagnation-point flow of a Newtonian fluid

    Science.gov (United States)

    Borrelli, A.; Giantesio, G.; Patria, M. C.; Roşca, N. C.; Roşca, A. V.; Pop, I.

    2017-02-01

    This work examines the steady three-dimensional stagnation-point flow of an electrically conducting Newtonian fluid in the presence of a uniform external magnetic field H0 under the Oberbeck-Boussinesq approximation. We neglect the induced magnetic field and examine the three possible directions of H0 which coincide with the directions of the axes. In all cases it is shown that the governing nonlinear partial differential equations admit similarity solutions. We find that the flow has to satisfy an ordinary differential problem whose solution depends on the Hartmann number M, the buoyancy parameter λ and the Prandtl number Pr. The skin-friction components along the axes are computed and the stagnation-point is classified. The numerical integration shows the existence of dual solutions and the occurrence of the reverse flow for some values of the parameters.

  3. Radiation effects on the MHD flow near the stagnation point of a stretching sheet: revisited

    Science.gov (United States)

    Pop, Ioan; Ishak, Anuar; Aman, Fazlina

    2011-10-01

    This paper considers the effects of radiation on the flow near the two-dimensional stagnation point of a stretching sheet immersed in a viscous and incompressible electrically conducting fluid in the presence of an applied constant magnetic field. The external velocity and the stretching velocity of the sheet are assumed to vary linearly with the distance from the stagnation point. The governing partial differential equations are transformed into a system of ordinary differential equations using a similarity transformation, before being solved numerically by the Keller-box method. The features of the heat transfer characteristics for different values of the governing parameters are analyzed and discussed. The results indicate that the heat transfer rate at the surface decreases in the presence of radiation.

  4. Magnetohydrodynamic stagnation point flow towards a stretching vertical sheet in a micropolar fluid

    Science.gov (United States)

    Ishak, A.; Nazar, R.; Pop, I.

    2007-03-01

    The analysis of steady two-dimensional stagnation point flow of an incompressible micropolar and electrically conducting fluid subject to a transverse uniform magnetic field towards a stretching vertical sheet is investigated when the sheet is stretched in its own plane with a velocity and a temperature proportional to the distance from the stagnation point. The governing system of partial differential equations is transformed to ordinary differential equations, which then are solved numerically using a finite difference scheme known as the Keller-box method. The velocity, microrotation and temperature distributions as well as the skin friction coefficient and the local Nusselt number are obtained for various parameters. Both the assisting and the opposing buoyant flows are considered. It is found that dual solutions exist for the opposing flow, for some regions of the buoyancy parameter, while for the assisting flow the solution is unique. Tables 3, Figs 14, Refs 26.

  5. Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier

    Science.gov (United States)

    Yu, Miao; Chen, Zongzheng; Xiang, Cheng; Liu, Bo; Xie, Handi; Qin, Kairong

    2016-06-01

    Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the relationship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier. The microfluidic device overcomes the weakness of the traditional ones, which have been only based upon either stagnation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addition, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system. It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and conveniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments.

  6. Effect of Stagnation Temperature on the Supersonic Two Dimensional Plug Nozzle Conception. Application for Air

    Institute of Scientific and Technical Information of China (English)

    Toufik Zebbiche; ZineEddine Youbi

    2007-01-01

    When the stagnation temperature of a perfect gas increases, the specific heats and their ratio do not remain constant any more and start to vary with this temperature. The gas remains perfect, its state equation remains always valid, except it will name in more calorically imperfect gas or gas at High Temperature. The goal of this research is to trace the profiles of the supersonic plug nozzle when this stagnation temperature is taken into account, lower than the threshold of dissociation of the molecules, by using the new formula of the Prandtl Meyer function, and to have for each exit Mach number, several nozzles shapes by changing the value of this temperature. A study on the error given by the PG (perfect gas) model compared to our model at high temperature is presented. The comparison is made with the case of a calorically perfect gas aiming to give a limit of application of this model. The application is for the air.

  7. Current redistribution and generation of kinetic energy in the stagnated Z pinch.

    Science.gov (United States)

    Ivanov, V V; Anderson, A A; Papp, D; Astanovitskiy, A L; Talbot, B R; Chittenden, J P; Niasse, N

    2013-07-01

    The structure of magnetic fields was investigated in stagnated wire-array Z pinches using a Faraday rotation diagnostic at the wavelength of 266 nm. The distribution of current in the pinch and trailing material was reconstructed. A significant part of current can switch from the main pinch to the trailing plasma preheated by x-ray radiation of the pinch. Secondary implosions of trailing plasma generate kinetic energy and provide enhanced heating and radiation of plasma at stagnation. Hot spots in wire-array Z pinches also provide enhanced radiation of the Z pinch. A collapse of a single hot spot radiates 1%-3% of x-ray energy of the Z pinch with a total contribution of hot spots of 10%-30%.

  8. The Role of Rumination and Stressful Life Events in the Relationship between the Qi Stagnation Constitution and Depression in Women: A Moderated Mediation Model

    Directory of Open Access Journals (Sweden)

    Mingfan Liu

    2017-01-01

    Full Text Available The qi stagnation constitution is associated with depression in traditional Chinese medicine. It is unclear how rumination and stressful life events affect the relationship between the qi stagnation constitution and depression. The Qi Stagnation Constitution Scale, Ruminative Response Scale, Center for Epidemiologic Studies Depression Scale, and Adolescent Self-Rating Life Events Checklist were used to assess this association in 1200 female college students. The results revealed that the qi stagnation constitution was positively associated with depression. Furthermore, rumination was a partial mediator of the relationship between the qi stagnation constitution and depression. In addition, stressful life events moderated the direct effect and mediating effect of the qi stagnation constitution on depression. These findings indicate that rumination and stressful life events may affect the relationship between the qi stagnation constitution and depression in women.

  9. Group classification of steady two-dimensional boundary-layer stagnation-point flow equations

    OpenAIRE

    Nadjafikhah, Mehdi; Hejazi, Seyed Reza

    2010-01-01

    Lie symmetry group method is applied to study the boundary-layer equations for two-dimensional steady flow of an incompressible, viscous fluid near a stagnation point at a heated stretching sheet placed in a porous medium equation. The symmetry group and its optimal system are given, and group invariant solutions associated to the symmetries are obtained. Finally the structure of the Lie algebra symmetries is determined.

  10. Dynamics of an unsteady stagnation vortical flow via dynamic mode decomposition analysis

    Science.gov (United States)

    Pan, Chong; Wang, Jianjie; Wang, Jinjun; Sun, Mao

    2017-03-01

    The dynamics of a large-scale stagnation vortex pair in an axisymmetric stagnation flow subject to a laminar wake disturbance is measured by time-resolved two-dimensional particle image velocimetry, and then quantitatively characterized by both the Eulerian velocity/vorticity fields and the Lagrangian finite-time Lyapunov exponents fields. This vortex pair is found to be the result of the forced response of the stagnation flow to the upstream shearing disturbances, and presents a dynamical evolution of quasi-periodic shedding due to short-wave elliptical instability. Dynamic mode decomposition analysis of both the Eulerian measure and the Lagrangian measure is taken for a quantitative description of this process. The sparsity-promoting scheme (Jovanović et al. Phys Fluids 26(2):024,103, 2014), which integrates the mode identification and truncation as a whole, is used to distinguish those modes with dynamical significance from irrelevant ones with transient behavior. The superiority of this scheme is evidenced by the facts that it avoids the eigenvalue contamination problem, and credits higher priority to the sub-dominant modes directly associated with the system dynamics. It is found that the energetic mode with a frequency of 0.177 Hz, or about 10% of the maximum shear rate of the upstream wake, determines the quasi-periodical vortex formation process. Its half-order harmonic represents the vortex shedding event along one fixed direction. High-order even-quarter harmonics jointly contribute to the circular pattern of the vortex tube. In addition, a set of low-frequency odd-quarter harmonics are highlighted as the elliptical instability and the following vortex deformation process. Based on this finding, a reduce-order representation with 8 Eulerian modes or 56 Lagrangian modes is proposed to characterize the dominant dynamics of this unsteady vortical stagnation flow. In addition, the Eulerian measure seems to be more efficient than the Lagrangian measure in

  11. Population growth, saving, interest rates and stagnation: Discussing the Eggertsson-Mehrotra model

    OpenAIRE

    Spahn, Peter

    2016-01-01

    Post Keynesian stagnation theory argues that slower population growth dampens consumption and investment. A New Keynesian OLG model derives an unemployment equilibrium due to a negative natural rate in a three-generations credit contract framework. Besides deleveraging or rising inequality, also a shrinking population is a triggering factor. In all cases, a saving surplus drives real interest rates down. In other OLG settings however, with bonds as stores of value, slower population growth, o...

  12. TRANSFORMATION VERSUS STAGNATION IN THE OIL PALM INDUSTRY: A COMPARISON BETWEEN MALAYSIA AND NIGERIA

    OpenAIRE

    Kajisa, Kei; Maredia, Mywish K.; Boughton, Duncan

    1997-01-01

    This paper contrasts the successful transformation of the oil palm sector in Malaysia with the stagnation of the oil palm sector in Nigeria, and examines the factors determining the different paths that the oil palm sectors took in these two countries with the aim of drawing lessons for future development and transfer strategy in Nigeria. Comparing two countries in different regions is not easy, especially when Nigeria has been in political chaos and the agro-climatic environments for oil-pal...

  13. Unsteady free convection of a stagnation point of attachment on an isothermal surface

    OpenAIRE

    D. B. Ingham; Merkin, J H; Pop, I.

    1984-01-01

    The time development free convection flow near a three-dimensional stagnation point of attachment on an isothermal surface is studied at large Grashof numbers. A small time solution and an accurate numerical method is described for determining the solution of the time-dependent boundary-layer equations. For a range of values of parameter c, which describes the local geometry, the development of the various physical properties of the flow are calculated and compared with their values at small ...

  14. Patterns and Predictors of Adolescent Academic Achievement and Performance in a Sample of Children with Attention-Deficit/Hyperactivity Disorder (ADHD)

    Science.gov (United States)

    Langberg, Joshua M.; Molina, Brooke S.G.; Arnold, L. Eugene; Epstein, Jeffery N.; Altaye, Mekibib; Hinshaw, Stephen P.; Swanson, James M.; Wigal, Timothy; Hechtman, Lily

    2011-01-01

    Examined predictors of academic achievement, measured by standardized test scores, and performance, measured by school grades, in adolescents (Mage=16.8 yr) who met diagnostic criteria for ADHD-Combined type in early childhood (Mage = 8.5; N = 579). Several mediation models were also tested to determine whether ADHD medication use, receipt of special education, classroom performance, homework completion, or homework management mediated the relationship between symptoms of ADHD and academic outcomes. Childhood predictors of adolescent achievement differed from those for performance. Classroom performance and homework management mediated the relationship between symptoms of inattention and academic outcomes. Implications for understanding the relationship between symptoms of ADHD and academic functioning are discussed. PMID:21722025

  15. The influence of the stagnation zone on the fluid dynamics at the nozzle exit of a confined and submerged impinging jet

    Science.gov (United States)

    Jeffers, Nicholas; Stafford, Jason; Conway, Ciaran; Punch, Jeff; Walsh, Edmond

    2016-02-01

    Low profile impinging jets provide a means to achieve high heat transfer coefficients while occupying a small quantity of space. Consequently, they are found in many engineering applications such as electronics cooling, annealing of metals, food processing, and others. This paper investigates the influence of the stagnation zone fluid dynamics on the nozzle exit flow condition of a low profile, submerged, and confined impinging water jet. The jet was geometrically constrained to a round, 16-mm diameter, square-edged nozzle at a jet exit to target surface spacing ( H/ D) that varied between 0.25 flow regimes is the main focus of this paper; however, laminar flow data are also presented between 1350 measurement facility was designed and commissioned to utilise particle image velocimetry in order to quantitatively measure the fluid dynamics both before and after the jet exits its nozzle. The velocity profiles are normalised with the mean velocity across the nozzle exit, and turbulence statistics are also presented. The primary objective of this paper is to present accurate flow profiles across the nozzle exit of an impinging jet confined to a low H/ D, with a view to guide the boundary conditions chosen for numerical simulations confined to similar constraints. The results revealed in this paper suggest that the fluid dynamics in the stagnation zone strongly influences the nozzle exit velocity profile at confinement heights between 0 0.5—where D is the inner diameter of the jet—in order to minimise modelling uncertainty.

  16. Long-term costs of inflated self-estimate on academic performance among adolescent students: a case of second-language achievements.

    Science.gov (United States)

    Yang, Mu-Li; Chuang, Hsueh-Hua; Chiou, Wen-Bin

    2009-12-01

    Past studies suggest that the adaptive or maladaptive consequences of inflated self-estimate, one form of positive illusions, require further investigation. 308 freshmen at a junior college (164 women, 144 men; M age = 19.8 yr., SD = 1.1) participated in a longitudinal study during a 2-yr. period. There were three assessments of short- and long-term effects of overly positive self-estimates on second-language achievement. Students' overestimation of subsequent performance appears to be associated with lower achievement. Those students with apparently inflated self-estimates performed marginally better on the first assessment but worse in the second and final assessments. Students with more accurate self-estimates showed improvement on all assessments. The findings suggested that overinflated self-estimates, i.e., positive illusions, among adolescent students might lead to a lower achievement over the long-term.

  17. The Effect of Performance-Pay in Little Rock, Arkansas on Student Achievement. Working Paper 2008-02

    Science.gov (United States)

    Winters, Marcus; Greene, Jay P.; Ritter, Gary; Marsh, Ryan

    2008-01-01

    This paper examines evidence from a performance-pay program implemented in five Little Rock, Arkansas elementary schools between 2004 and 2007. Using a differences-in-differences approach, the evidence shows that students whose teachers were eligible for performance pay made substantially larger test score gains in math, reading, and language than…

  18. The Effects of Intercollegiate Athletic Participation on Student Academic Achievement and Leadership Performance in a Selective Institution

    Science.gov (United States)

    Yunker, Craig Andrew

    2009-01-01

    The purpose of this study was to examine the influence of various intensity levels of athletic participation on academic and leadership performance in a selective institution. For the purpose of this study a retrospective analysis of existing admissions and student performance data was conducted. The continuous dependent variables were academic…

  19. Adhesion of leukocytes under oscillating stagnation point conditions: a numerical study.

    Science.gov (United States)

    Walker, P G; Alshorman, A A; Westwood, S; David, T

    2002-01-01

    Leukocyte recruitment from blood to the endothelium plays an important role in atherosclerotic plaque formation. Cells show a primary and secondary adhesive process with primary bonds responsible for capture and rolling and secondary bonds for arrest. Our objective was to investigate the role played by this process on the adhesion of leukocytes in complex flow. Cells were modelled as rigid spheres with spring like adhesion molecules which formed bonds with endothelial receptors. Models of bond kinetics and Newton's laws of motion were solved numerically to determine cell motion. Fluid force was obtained from the local shear rate obtained from a CFD simulation of the flow over a backward facing step.In stagnation point flow the shear rate near the stagnation point has a large gradient such that adherent cells in this region roll to a high shear region preventing permanent adhesion. This is enhanced if a small time dependent perturbation is imposed upon the stagnation point. For lower shear rates the cell rolling velocity may be such that secondary bonds have time to form. These bonds resist the lower fluid forces and consequently there is a relatively large permanent adhesion region.

  20. Modification of stagnation conditions in Magnetized Liner Inertial Fusion via thick dielectric coating

    Science.gov (United States)

    Gomez, M. R.; Harding, E. C.; Peterson, K. J.; Awe, T. J.; Ampleford, D. J.; Hansen, S. B.; Jennings, C. A.; Weis, M. R.; Chandler, G. A.; Hahn, K. D.; Knapp, P. F.; Martin, M. R.; McBride, R. D.; Rochau, G. A.; Sefkow, A. B.; Sinars, D. B.; Yu, E. P.

    2016-10-01

    Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z facility at Sandia National Laboratories use approximately 20 MA of current to implode a metal cylinder, which contains axially-magnetized, laser-heated deuterium fuel. MagLIF experiments have demonstrated primary DD neutron yields up to 3e12 with burn averaged ion temperatures of 2.5 keV. X-ray emission at stagnation, recorded with a spherically-bent crystal imager, shows a weakly-helical structure with axial variations in intensity. Previously, the application of a thick dielectric coating to the exterior of an imploding cylinder has shown improved stability of the cylinder throughout the implosion. We recently demonstrated that adding a dielectric coating to a MagLIF target produces a cylindrical, rather than helical, stagnation column with reduced axial variations in intensity. There are also indications of decreased late-time mix in the x-ray spectra. This is consistent with a more uniform, stable stagnation column. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  1. The Effect of Performance Assessment-Driven Instruction on the Attitude and Achievement of Senior High School Students in Mathematics in Cape Coast Metropolis, Ghana

    Science.gov (United States)

    Arhin, Ato Kwamina

    2015-01-01

    The study was a quasi-experimental research project conducted to investigate the effect of performance assessment-driven instructions on the attitude and achievement in mathematics of senior high school students in Ghana at Ghana National College in Cape Coast. Two Form 1 science classes were used for the study and were assigned as experimental…

  2. Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance, and academic achievement in Dutch adolescents

    NARCIS (Netherlands)

    De Groot, Renate; Ouwehand, Carolijn; Jolles, Jelle

    2012-01-01

    De Groot, R. H. M., Ouwehand, C., & Jolles, J. (2011, 2 September). Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance and academic achievement in Dutch adolescents. Poster presented at the the 14th biannual EARLI conference, Exeter, Unit

  3. Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance and academic achievement in Dutch adolescents

    NARCIS (Netherlands)

    De Groot, Renate; Ouwehand, Carolijn; Jolles, Jelle

    2012-01-01

    De Groot, R. H. M., Ouwehand, C., & Jolles, J. (2012). Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance and academic achievement in Dutch adolescents. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 86(3), 113-117. doi:10.1016/

  4. Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance, and academic achievement in Dutch adolescents

    NARCIS (Netherlands)

    De Groot, Renate; Ouwehand, Carolijn; Jolles, Jelle

    2012-01-01

    De Groot, R. H. M., Ouwehand, C., & Jolles, J. (2012, May). Eating the right amount of fish: Inverted U-shape association between fish consumption and cognitive performance, and academic achievement in Dutch adolescents. Paper presented at the 10th Congress of the International Society for the Study

  5. A New Numerical Solution of Maxwell Fluid over a Shrinking Sheet in the Region of a Stagnation Point

    OpenAIRE

    S. S. Motsa; Khan, Y.; S. Shateyi

    2012-01-01

    The mathematical model for the incompressible two-dimensional stagnation flow of a Maxwell fluid towards a shrinking sheet is proposed. The developed equations are used to discuss the problem of being two dimensional in the region of stagnation point over a shrinking sheet. The nonlinear partial differential equations are transformed to ordinary differential equations by first-taking boundary-layer approximations into account and then using the similarity transformations. The obta...

  6. Building trust through promises and performance. Can your organization achieve the stellar results and employee loyalty found at Southwest Airlines?

    Science.gov (United States)

    O'Connor, Edward J; Annison, Michael H

    2002-01-01

    Establishing a trusting relationship with your employees can help you transform your organization into a top performer. Examine how well-defined visions and goals are some of the keys to building that trust.

  7. An Initial Study of Relationships among the R&D Productivities of Patent Inventors in Patent, Academic Achievement and Professional Performances - An Example of Pixar Animation Studies

    Directory of Open Access Journals (Sweden)

    Mei-Yin Chen

    2004-09-01

    Full Text Available Patent information is seen to be a kind of information with the features of exactitude and trustfulness, and it can be used as an indicator to measure the capability of research and development in a company. This research initially explores the relationships among the R&D productivities of patent inventors in patents, academic achievements and professional performances in terms of a patent production aspect. Our research object is the Pixar Company, which had been devoted to 3D animation production for a long time and become one of the key players in the industry. This paper presents a study to discover the technical human resource in the company based on inventor analyses from patent information. Three problems were addressed as follows: (1 Pixar’s key inventors and their active periods, (2 the collaboration among these inventors, and (3 their academic achievements and professional performances and then examined their relationships among the patents, academic achievements and professional performances. In the study, we produced a graph to depict the collaboration of patent inventors when they cooperated to develop technologies and applied patents, and finally we integrated the graph with the search results from the ACM database and the IMDB databases to synthesize another graph to demonstrate the relationships among the productivities of key patent inventors in patents, academic achievements and professional performances. The findings show that in the digital content industry the performances of patent producing of technical talents principally come from the accumulation of their academic ability. When they applied the knowledge and the competence to the industry, they not only achieved remarkable success but also gained confirmation from international awards. Finally, the study also approved the potential and the feasibility of applying knowledge and techniques of bibliometrics to industrial analysis. [Article content in Chinese

  8. Attendance and achievement in medicine: investigating the impact of attendance policies on academic performance of medical students.

    Science.gov (United States)

    Subramaniam, Bs; Hande, S; Komattil, R

    2013-04-01

    The attendance mandate for the medical course in Melaka Manipal Medical College, Manipal, India was increased from 75% to 90% based on the assumption that the mandatory increase will improve the students' performance. To find out whether there is any correlation between class attendance and academic performance. This was an institution based retrospective analytical study. Students who have completed Phase I (first two and a half years) of the MBBS course were included in the study. Student marks and attendance, from the database were obtained from three random batches, each, from two clusters A and B respectively. Those who had a mandatory attendance requirement of 75% belonged to A (n = 243), and those who had a mandatory attendance percentage of 90% belonged to B (n = 360). Statistical analyses performed included, Pearson 2 tailed correlation to correlate class attendance with student performance; Cluster analysis to classify group average in a similarity matrix; t-test to determine significance of difference in percentage of students who attained 100% when the college changed mandatory attendance from 75% to 90%; Mann-Whitney test to find out if there was a better performance in university exam when attendance policy changed. There was a significant correlation between attendance and the students who passed in the University exam. The number of students in the pass category was maximum (>90%) compared to students in distinction and failed categories. Percentage of students with 100% attendance rose from 4% (n = 10) to 11% (n = 40) when the mandatory attendance was increased from 75% to 90%. Attendance policy correlated with better academic performance. Reducing absenteeism, probably contributed to the improved academic performance of the students. But the link between attendance and best and worst performances could not be predicted because of small numbers in every batch.

  9. Attendance and Achievement in Medicine: Investigating the Impact of Attendance Policies on Academic Performance of Medical Students

    OpenAIRE

    Subramaniam, BS; Hande, S; Komattil, R

    2013-01-01

    Background: The attendance mandate for the medical course in Melaka Manipal Medical College, Manipal, India was increased from 75% to 90% based on the assumption that the mandatory increase will improve the students’ performance. Aims: To find out whether there is any correlation between class attendance and academic performance. Subjects and Methods: This was an institution based retrospective analytical study. Students who have completed Phase I (first two and a half years) of the MBBS cour...

  10. Employing low-temperature barriers to achieve strain-relaxed and high-performance GaN-based LEDs.

    Science.gov (United States)

    Lin, Zhiting; Wang, Haiyan; Wang, Wenliang; Lin, Yunhao; Yang, Meijuan; Chen, Shuqi; Li, Guoqiang

    2016-05-30

    The epitaxial structure design of low-temperature barriers has been adopted to promote strain relaxation in multiple quantum well (MQWs) and achieve high-efficient GaN-based light-emitting diodes (LEDs). With these barriers, the relaxation value of wells increases from 0 to 4.59%. The strain-relaxed mechanism of low-temperature barriers is also discussed. The LED chip with the barriers grown at the TMIn flow of 75 sccm and the growth temperature of 830 °C has an optimal strain relaxation value of 1.53% in wells, and exhibits the largest light output power of 63.83 mW at the injection current of 65 mA, which is higher than that of conventional LED (51.89 mW) by 23%. In-depth studies reveal that the optimal low-temperature barriers remarkably promote the strain relaxation in wells without forming large density of crystalline defects. This achievement of high-efficiency LEDs sheds light on the future solid-state lighting applications.

  11. Final LDRD report : science-based solutions to achieve high-performance deep-UV laser diodes.

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Andrew M.; Miller, Mary A.; Crawford, Mary Hagerott; Alessi, Leonard J.; Smith, Michael L.; Henry, Tanya A.; Westlake, Karl R.; Cross, Karen Charlene; Allerman, Andrew Alan; Lee, Stephen Roger

    2011-12-01

    We present the results of a three year LDRD project that has focused on overcoming major materials roadblocks to achieving AlGaN-based deep-UV laser diodes. We describe our growth approach to achieving AlGaN templates with greater than ten times reduction of threading dislocations which resulted in greater than seven times enhancement of AlGaN quantum well photoluminescence and 15 times increase in electroluminescence from LED test structures. We describe the application of deep-level optical spectroscopy to AlGaN epilayers to quantify deep level energies and densities and further correlate defect properties with AlGaN luminescence efficiency. We further review our development of p-type short period superlattice structures as an approach to mitigate the high acceptor activation energies in AlGaN alloys. Finally, we describe our laser diode fabrication process, highlighting the development of highly vertical and smooth etched laser facets, as well as characterization of resulting laser heterostructures.

  12. Pre-admission criteria and pre-clinical achievement: Can they predict medical students performance in the clinical phase?

    Science.gov (United States)

    Salem, Raneem O; Al-Mously, Najwa; AlFadil, Sara; Baalash, Amal

    2016-01-01

    Various factors affect medical students' performance during clinical phase. Identifying these factors would help in mentoring weak students and help in selection process for residency programmes. Our study objective is to evaluate the impact of pre-admission criteria, and pre-clinical grade point average (GPA) on undergraduate medical students' performance during clinical phase. This study has a cross-sectional design that includes fifth- and sixth-year female medical students (71). Data of clinical and pre-clinical GPA in medical school and pre-admission to medical school tests scores were collected. A significant correlation between clinical GPA with the pre-clinical GPA was observed (p performed, and the only significant predictor of students clinical performance was the pre-clinical GPA (p GPA for both cohorts was observed (p > 0.05). Pre-clinical GPA is strongly correlated with and can predict medical students' performance during clinical years. Our study highlighted the importance of evaluating the academic performances of students in pre-clinical years before they move into clinical years in order to identify weak students to mentor them and monitor their progress.

  13. La motivación de logro mejora el rendimiento académico (Achievement Motivation Improves Academic Performance

    Directory of Open Access Journals (Sweden)

    Jose Miguel Garcia-Ramirez

    2016-01-01

    Full Text Available A través de los proyectos de innovación docente las universidades mejoran y consolidan la calidad de la educación que ofrecen, tomando la creatividad y visibilidad como claves de la motivación por competencias y logro. Método: La investigación se realiza durante el curso académico 2013-14, a través del proyecto de innovación docente “ReiDoCrea” de la Universidad de Granada. Los participantes (N=62, M=22.7, SD=6.6, estudiantes de la Facultad de Ciencias del Trabajo, se adscribieron voluntariamente al Grupo Experimental (n=30 o al Grupo Control (n=32. El grupo experimental participó en el proyecto, mientras que el grupo control no participó; los instrumentos utilizados fueron dos pruebas objetivas (pre y post del programa de evaluación académica. Resultados: El análisis estadístico muestra que existen diferencias significativas entre los resultados obtenidos por el Grupo Experimental (M=83.6, SE=1.259, t(60=3.748, p<.05, d=.95 r=.43 y el Grupo Control (M=77.25, SE=1.14. Conclusiones: En la innovación docente, la motivación por competencias y de logro es clave para desarrollar el pensamiento creativo y mejorar el rendimiento académico. Abstract: Through teaching innovation projects universities improve and consolidate the quality of education they offer, taking creativity and visibility as the key to competence and achievement motivation. Method: The research study was conducted during the academic year 2013-14, through the teaching innovation project "ReiDoCrea" of the University of Granada. The participants (N=62, M=22.7, SD=6.6, students of the Faculty of Labour, voluntarily joined the Experimental Group (n=30 or the Control Group (n=32. The experimental group participated in the project, while the Control Group did not participate; the instruments used were two objective tests (pre and post, part of the academic program evaluation. Results: The statistical analysis shows that there are significant differences between the

  14. La motivación de logro mejora el rendimiento académico (Achievement Motivation Improves Academic Performance

    Directory of Open Access Journals (Sweden)

    Jose Miguel Garcia-Ramirez

    2016-01-01

    Full Text Available A través de los proyectos de innovación docente las universidades mejoran y consolidan la calidad de la educación que ofrecen, tomando la creatividad y visibilidad como claves de la motivación por competencias y logro. Método: La investigación se realiza durante el curso académico 2013-14, a través del proyecto de innovación docente “ReiDoCrea” de la Universidad de Granada. Los participantes (N=62, M=22.7, SD=6.6, estudiantes de la Facultad de Ciencias del Trabajo, se adscribieron voluntariamente al Grupo Experimental (n=30 o al Grupo Control (n=32. El grupo experimental participó en el proyecto, mientras que el grupo control no participó; los instrumentos utilizados fueron dos pruebas objetivas (pre y post del programa de evaluación académica. Resultados: El análisis estadístico muestra que existen diferencias significativas entre los resultados obtenidos por el Grupo Experimental (M=83.6, SE=1.259, t(60=3.748, p<.05, d=.95, r=.43 y el Grupo Control (M=77.25, SE=1.14. Conclusiones: En la innovación docente, la motivación por competencias y de logro es clave para desarrollar el pensamiento creativo y mejorar el rendimiento académico. Abstract: Through teaching innovation projects universities improve and consolidate the quality of education they offer, taking creativity and visibility as the key to competence and achievement motivation. Method: The research study was conducted during the academic year 2013-14, through the teaching innovation project "ReiDoCrea" of the University of Granada. The participants (N=62, M=22.7, SD=6.6, students of the Faculty of Labour, voluntarily joined the Experimental Group (n=30 or the Control Group (n=32. The experimental group participated in the project, while the Control Group did not participate; the instruments used were two objective tests (pre and post, part of the academic program evaluation. Results: The statistical analysis shows that there are significant differences between the

  15. 浅论“火郁发之”%Discussion on "Fire Stagnation Requiring Dissipation"

    Institute of Scientific and Technical Information of China (English)

    杨琳; 张丽萍

    2015-01-01

    [目的]探究“火郁发之”的基本内涵,剖析历代医家关于火热病的论述,以期拓宽“火郁发之”在临床诊疗中的运用。[方法]运用概念思维的方法,对“火郁”的病因病机、“火郁发之”治则的具体内涵进行逐一阐述。搜集整理历代医家对“火郁发之”的论述,并列举相关方剂以深化思考。[结果]火郁之症的产生不外乎外感、内伤两端,其机理是人体中的火气受到某些因素的影响,升降出入之机失去常度,郁遏停滞在某一部位,火性不得泄越所致。《内经》中首载“火郁发之”,即对火郁之病,因势利导,通过宣发郁热,疏散郁结,使气之开合、升降、出入协调,机体恢复阴平阳秘的状态。张仲景在《伤寒论》较完备地论述了“火郁发之”的含义及机理。金元以降,历代医家对此多有发挥,或从外感,或从内伤,自成体系创立名方,使该理论得到进一步完善。[结论]自《内经》提出“火郁发之”理论以来,后世医家对火郁之证的认识逐步深化,为临床治疗提供了更加广阔的思路。近年来,“火郁发之”理论被广泛应用于各类疾病,其学术价值值得总结、继承、推广。%Objective]To explore the basic connotation of “fire stagnation requiring dissipation”and analyse ancient physicians' discussion about the fever, in order to expand its application in the clinical treatment.[Method] Using the method of conceptual thinking to explain the etiology and pathology of“fire stagnation”,the specific connotation of“fire stagnation requiring dissipation”,collecting ancient physicians' exposition on“fire stagnation requiring dissipation”,and listing the relevant prescriptions in order to deepen the thinking.[Result] Fire stagnation produces nothing more than exogenous ,internal injuries,the mechanism is in the human body, the anger's ascending-descending and

  16. The theory of“clearing stagnated fire”%论“火郁发之”

    Institute of Scientific and Technical Information of China (English)

    齐文升

    2015-01-01

    “火郁发之”,语出《内经》,后之贤哲,多所发明。“郁”为病理,喻闭塞之意;“发”乃治则,含透散之旨。“火郁发之”是言火热之邪郁闭于内,不可单施苦寒直折,尤当透散以发之。仲景开“火郁发之”之先河,河间以为表里诸热证皆可归于阳气怫郁,东垣独重脾胃,内伤之病皆由脾胃而始,阳气抑遏脾土,清气不得升发。余以为,阳气以动为常,以行为用,盖当今之世,工业污染,农烟似霭;人处华栋,冬如暖夏,夏似凉冬,天地交济既失;人复生息失慎,焦虑紧张,激怒愤懑,气血常悖于内,渐至郁怫生火,郁火暗生,故治必内安其心,外适天地,天地人以位,方可身安立命,远疾疢矣。故医也者,顺天之时,测气之偏,顺气开结,引路去邪,从火之性,发火之郁。谨候气宜,无失病机,谨道如法,长有天命。%The theory of “clearing stagnated fire”is firstly written in Inner Canon of Huangdi.The later generation who are wise and able give different explanations. Stagnation is pathological, meaning blocking.Clearing is therapeutic principle, meaning clarity and let out.Clearing stagnated fire means pathogenic fire and heat are blocked in the body, treatment could not be carried out with bitter-cold herbs, and clear and divulge herbs is preferred.ZHANG Zhongjing is the first person who started using the theory of clearing stagnated fire.LIU Hejian attributes the heat syndrome from exterior to interior to stagnated yang qi.LI Dongyuan attaches importance to spleen and stomach, and believes that internal diseases are originated from spleen and stomach, yang qi restralns spleen which stops the ascending and dredging of clear qi.It is considered by the author that yang qi moves regularly, and works when circulating.In modern society, the industrial pollution is severe, and the smoke is extremely heavy;People lives in

  17. New optical method for heat flux measurements in stagnation point laminar methane/air flames and hydrogen/methane/air flames using thermographic phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Elmnefi, Mohamed Salem

    2010-11-24

    In the present study, a new optical method was implemented to study the heat transfer from flat stagnation point flames which can be regarded as one-dimensional in the central part. Premixed methane-air flames and hydrogen-methane-air flames were investigated. The effects of burner-to-plate distance and the fresh gas mixture velocity on heat transfer were examined. Experiments were performed using light induced phosphorescence from thermographic phosphors to study the wall temperatures and heat fluxes of nearly one-dimensional flat premixed flames impinging upward normally on a horizontal water cooled circular flat plate. The investigated flames were stoichiometric, lean and rich laminar methane/air flames with different equivalence ratios of {phi} =1, {phi} = 0.75 and {phi} = 1.25 and stoichiometric laminar hydrogen/methane/air flames. Mixtures of air with 10, 25, 50 and 75 % hydrogen in methane (CH{sub 4}) as well as a pure hydrogen flames at ambient pressure were investigated. The central part of this plate was an alumina ceramic plate coated from both sides with chromium doped alumina (ruby) and excited with a Nd:YAG laser or a green light emitting diode (LED) array to measure the wall temperature from both sides and thus the heat flux rate from the flame. The outlet velocity of the gases was varied from 0.1 m/s to 1.2 m/s. The burner to plate distance ranged from 0.5 to 2 times the burner exit diameter (d = 30 mm).The accuracy of the method was evaluated. The measured heat flux indicate the change of the flame stabilization mechanism from a burner stabilized to a stagnation plate stabilized flame. The results were compared to modeling results of a one dimensional stagnation point flow, with a detailed reaction mechanism. In order to prove the model, also measured gas phase temperatures by OH LIF for a stoichiometric stagnation point flame were discussed. It turns out that the flame stabilization mechanism and with it the heat fluxes change from low to high

  18. Students' perceptions of rewards for academic performance by parents and teachers: relations with achievement and motivation in college.

    Science.gov (United States)

    Davis, Kelly D; Winsler, Adam; Middleton, Michael

    2006-06-01

    In the present study, the authors examined college students' (N= 136) perceptions of the provision of extrinsic rewards given by parents and teachers for academic performance from elementary school through high school. They also examined the relations between reward history and present student motivational orientation. External rewards for students' grades were common at all levels of schooling. Reward history related significantly to students' motivational orientation and performance in college, and these relations were generally stronger for boys than for girls. The authors discuss implications of these findings.

  19. The Influence of Parenting Styles, Achievement Motivation, and Self-Efficacy on Academic Performance in College Students

    Science.gov (United States)

    Turner, Erlanger A.; Chandler, Megan; Heffer, Robert W.

    2009-01-01

    Parenting styles have consistently been shown to relate to various outcomes such as youth psychopathology, behavior problems, and academic performance. Building on the research in the parenting style literature, along with examining components of self-determination theory, the present study examined the relations among authoritative parenting…

  20. The Utility of Curriculum-Based Measurement and Performance Assessment as Alternatives to Traditional Intelligence and Achievement Tests.

    Science.gov (United States)

    Elliott, Stephen N.; Fuchs, Lynn S.

    1997-01-01

    Curriculum-based measurement and performance assessments can provide valuable data for making special-education eligibility decisions. Reviews applied research on these assessment approaches and discusses the practical context of treatment validation and decisions about instructional services for students with diverse academic needs. (Author/JDM)

  1. The Influence of Parenting Styles, Achievement Motivation, and Self-Efficacy on Academic Performance in College Students

    Science.gov (United States)

    Turner, Erlanger A.; Chandler, Megan; Heffer, Robert W.

    2009-01-01

    Parenting styles have consistently been shown to relate to various outcomes such as youth psychopathology, behavior problems, and academic performance. Building on the research in the parenting style literature, along with examining components of self-determination theory, the present study examined the relations among authoritative parenting…

  2. A cross-country comparison of math achievement at teen age and cognitive performance 40 years later

    Directory of Open Access Journals (Sweden)

    Vegard Skirbekk

    2014-07-01

    Full Text Available Background: Maintaining cognitive functioning through mid- to late-life is relevant for the individual and societal aim of active ageing. Evidence shows considerable stability in individual-level rank-ordering of cognitive functioning, but little attention has been given to cohort performance over the life cycle and macro-level factors that could affect it. Objective: The main goal of this paper is to address cross-national variation in mental performance from younger to older ages. Methods: Using a quasi-longitudinal approach, we compare the relative country ranking in standardised mathematical test scores at teen age in 1964 from the First International Mathematics Study (FIMS and cognitive test performance at mid-life in 2004, based on the Survey of Health, Ageing and Retirement in Europe (SHARE for the cohort born between 1949 and 1952. Results: Our results show that those countries which had the highest scores in math tests taken by 13 years old grade level students are not the same countries that, 40 years later, have the top performing scores in cognitive tests among mid-age adults. Conclusions: This article highlights the importance of considering country-level influences on cognitive change over the life cycle, in addition to individual characteristics, and provides some descriptive findings that could be incorporated with further research on the link between specific contextual factors and cognitive functioning.

  3. Supervised, Multivariate, Whole-brain Reduction Did Not Help to Achieve High Classification Performance in Schizophrenia Research

    Directory of Open Access Journals (Sweden)

    Eva Janousova

    2016-08-01

    Full Text Available We examined how penalized linear discriminant analysis with resampling, which is a supervised, multivariate, whole-brain reduction technique, can help schizophrenia diagnostics and research. In an experiment with magnetic resonance brain images of 52 first-episode schizophrenia patients and 52 healthy controls, this method allowed us to select brain areas relevant to schizophrenia, such as the left prefrontal cortex, the anterior cingulum, the right anterior insula, the thalamus and the hippocampus. Nevertheless, the classification performance based on such reduced data was not significantly better than the classification of data reduced by mass univariate selection using a t-test or unsupervised multivariate reduction using principal component analysis. Moreover, we found no important influence of the type of imaging features, namely local deformations or grey matter volumes, and the classification method, specifically linear discriminant analysis or linear support vector machines, on the classification results. However, we ascertained significant effect of a cross-validation setting on classification performance as classification results were overestimated even though the resampling was performed during the selection of brain imaging features. Therefore, it is critically important to perform cross-validation in all steps of the analysis (not only during classification in case there is no external validation set to avoid optimistically biasing the results of classification studies.

  4. Students' Perceptions of Rewards for Academic Performance by Parents and Teachers: Relations with Achievement and Motivation in College

    Science.gov (United States)

    Davis, Kelly D.; Winsler, Adam; Middleton, Michael

    2006-01-01

    In the present study, the authors examined college students' (N = 136) perceptions of the provision of extrinsic rewards given by parents and teachers for academic performance from elementary school through high school. They also examined the relations between reward history and present student motivational orientation. External rewards for…

  5. [Changes of HPAA in Different Rat Models of Gan Stagnation, Pi Deficiency, Gan Stagnation Pi Defi- ciency and Interventional Effect of Chaishu Sijun Decoction].

    Science.gov (United States)

    Zhao, Rong-hua; Liu, Jin-na; Li, Cong; Zhang, Jing-sheng; Wang, Bang-zhong; Yao, Yuan-chao; Xie, Ming; Wang, Dao-han

    2015-07-01

    To compare changes of hypothalamus-pituitary-adrenal axis (HPAA) in different rat models of Gan stagnation (GS), Pi deficiency (PD), Gan stagnation Pi deficiency (GSPD) syndromes, and to observe interventional effect of Chaishu Sijun Decoction (CSD, capable of soothing Gan-qi invigorating Pi) on them. Seventy Wistar rats were divided into the normal control group (group 1), the GS group (group 2), the PD group (group 3), the GSPD group (group 4), the GS intervention group (group 5), the PD intervention group (group 6), and the GSPD intervention group (group 7) according to random digit table, 10 in each group. Rats in group 1 received no treatment. Rats in group 2 and 5 were modeled by chronic restraint method. Rats in group 3 and 6 were modeled by excess fatigue plus alimentary abstinence method. Rats in group 4 and 7 were modeled by chronic restraint, excess fatigue, and alimentary abstinence method. At the 2nd weekend of modeling, CSD at 2.86 g/kg was fed to rats in group 5, 6, and 7 by gastrogavage for 2 successive weeks. Equal volume of distilled water was given to rats in the rest 4 groups. On the 29th day, rats were killed, adrenal weight weighed, and adrenal index calculated. Levels of plasma and hypothalamus corticotropin-releasing hormone (CRH), plasma and pituitary adrenocorticotrophic hormone (ACTH), and plasma corticosterone (CORT) were determined using radioimmunity. Compared with group 1, adrenal index significantly decreased in group 2, 3, and 4 (P HPAA, but with optimal effect on GSPD syndrome. CSD had higher correlation with GSPD syndrome.

  6. Control-value theory: using achievement emotions to improve understanding of motivation, learning, and performance in medical education: AMEE Guide No. 64.

    Science.gov (United States)

    Artino, Anthony R; Holmboe, Eric S; Durning, Steven J

    2012-01-01

    In this AMEE Guide, we consider the emergent theoretical and empirical work on human emotion and how this work can inform the theory, research, and practice of medical education. In the Guide, we define emotion, in general, and achievement emotions, more specifically. We describe one of the leading contemporary theories of achievement emotions, control-value theory (Pekrun 2006), and we distinguish between different types of achievement emotions, their proximal antecedents, and their consequences for motivation, learning, and performance. Next, we review the empirical support for control-value theory from non-medical fields and suggest several important implications for educational practice. In this section, we highlight the importance of designing learning environments that foster a high degree of control and value for students. Finally, we end with a discussion of the need for more research on achievement emotions in medical education, and we propose several key research questions we believe will facilitate our understanding of achievement emotions and their impact on important educational outcomes.

  7. Using efficiency analysis and targeted intervention to improve operational performance and achieve cost savings in the endoscopy center.

    Science.gov (United States)

    Kaushal, Neal K; Chang, Kenneth; Lee, John G; Muthusamy, V Raman

    2014-04-01

    With an increasing demand for endoscopy services, there is a greater need for efficiency within the endoscopy center. A validated methodology is important for evaluating efficiency in the endoscopy unit. To use the principles of operations management to establish a validated methodology for evaluating and enhancing operational performance in the endoscopy center. Biphasic prospective study with pre-intervention and post-intervention efficiency data and analysis. Tertiary-care referral teaching hospital. Scheduled outpatients undergoing endoscopy. Determination of the rate-limiting step, or bottleneck, of the endoscopy unit and reducing inefficiencies. Staffing costs and a novel performance metric, True Completion Time (TCT). Data were prospectively recorded for 2248 patients undergoing a total of 2713 procedures (phase I: 255 EGD, 305 colonoscopy, 91 EGD/colonoscopy, 375 EUS, 44 ERCP, 75 EUS/ERCP; phase II: 243 EGD, 328 colonoscopy, 99 EGD/colonoscopy, 335 EUS, 38 ERCP, 109 EUS/ERCP). The bottleneck of the operation was identified as the 10-bed communal pre-procedure/recovery room. On-time procedure starts increased by 51% (P costs were reduced by 30%, whereas full-time employee staff was reduced by 0.85. Annual cost savings were calculated as $312,618 or 11.02% of total operating expenses. This study is not directly tied to quality outcomes, and inpatient procedures transported to the endoscopy unit were not directly studied. Room turnover time and room-to-endoscopist ratio are not necessarily the driving parameters behind endoscopy unit efficiency. A focus on developing a methodology for identifying factors constraining operational efficiency can improve performance and reduce costs in the endoscopy center. Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  8. Effects of heat exposure and 3% dehydration achieved via hot water immersion on repeated cycle sprint performance.

    Science.gov (United States)

    Kraft, Justin A; Green, James M; Bishop, Phillip A; Richardson, Mark T; Neggers, Yasmin H; Leeper, James D

    2011-03-01

    This study examined effects of heat exposure with and without dehydration on repeated anaerobic cycling. Males (n = 10) completed 3 trials: control (CT), water-bath heat exposure (∼39°C) to 3% dehydration (with fluid replacement) (HE), and similar heat exposure to 3% dehydration (DEHY). Hematocrit increased significantly from pre to postheat immersion in both HE and DEHY. Participants performed 6 × 15s cycle sprints (30s active recovery). Mean Power (MP) was significantly lower vs. CT (596 ± 66 W) for DEHY (569 ± 72 W), and the difference approached significance for HE (582 ± 76 W, p = 0.07). Peak Power (PP) was significantly lower vs. CT (900 ± 117 W) for HE (870 ± 128 W) and approached significance for DEHY (857 ± 145 W, p = 0.07). Postsprint ratings of perceived exertion was higher during DEHY (6.4 ± 2.0) and HE (6.3 ± 1.6) than CT (5.7 ± 2.1). Combined heat and dehydration impaired MP and PP (decrements greatest in later bouts) with HE performance intermediate to CT and DEHY.

  9. Characterization of Pulse Detonation Engine Performance with Varying Free Stream Stagnation Pressure Levels

    Science.gov (United States)

    2006-03-01

    compressible 38 flow equations. The Quad 4 cylinder head is a standard cylinder head with a dual overhead camshaft . As when installed in an...automobile engine each camshaft independently opens and closes a set of 8 purge and 8 fill valves. The camshaft lobes are each geometrically designed for...given lift and duration. The lift of a camshaft lobe refers to the overall distance the valve will be moved off the seat at maximum lift. The

  10. Low Pressure Flame Blowoff from the Forward Stagnation Region of a Blunt-Nosed Cast PMMA Cylinder in Axial Mixed Convective Flow

    Science.gov (United States)

    Marcum, J. W.; Rachow, P.; Ferkul, P. V.; Olson, S. L.

    2017-01-01

    Low-pressure blowoff experiments were conducted with a stagnation flame stabilized on the forward tip of cast PMMA rods in a vertical wind tunnel. Pressure, forced flow velocity, gravity, and ambient oxygen concentration were varied. Stagnation flame blowoff is determined from a time-stamped video recording of the test. The blowoff pressure is determined from test section pressure transducer data that is synchronized with the time stamp. The forced flow velocity is also determined from the choked flow orifice pressure. Most of the tests were performed in normal gravity, but a handful of microgravity tests were also conducted to determine the influence of buoyant flow velocity on the blowoff limits. The blowoff limits are found to have a linear dependence between the partial pressure of oxygen and the total pressure, regardless of forced flow velocity and gravity level. The flow velocity (forced and/or buoyant) affects the blowoff pressure through the critical Damkohler number residence time, which dictates the partial pressure of oxygen at blowoff. This is because the critical stretch rate increases linearly with increasing pressure at low pressure (sub-atmospheric pressures) since a second-order overall reaction rate with two-body reactions dominates in this pressure range.

  11. The Development and Testing of Laboratory Performance Tasks for the Assessment of Achievement in High School Physics.

    Science.gov (United States)

    Boorman, Joan Marie

    The quest to stem "the rising tide of mediocrity" described in A Nation at Risk has prompted a myriad of changes in secondary science instruction. Appropriate assessments of these changes in curriculum are crucial to a meaningful evaluation of their effectiveness. Because the nature of many of the improvements has been to engage students in higher order thinking skills, simple paper and pencil tests are often inconclusive evaluation measures. Research has shown a more definitive assessment of a student's ability to apply higher order thinking skills is possible with tests of performance in problem-solving tasks in a science laboratory. The Physics Laboratory Skills Test (PLST) was developed as a prototype assessment instrument for evaluation of student ability to perform a range of process skills in the high school physics laboratory setting. The PLST included seven different items based on topics presented in a typical high school physics course. Each item constituted a separate laboratory performance test and was completed by individual students in a 40 minute class period. A sample of 219 physics students from rural, urban, public, and private schools in NY and PA were tested with the PLST in May 1990. Results of this study show that the PLST has usability, validity, and reliability as an assessment of basic skills (measuring and reporting) and higher order skills (planning and analysis). Participating teachers determined the PLST to be an appropriate and useful tool in evaluating individual student abilities. Content validity was established via evaluation by 'expert' high school physics teachers. The Pearson Correlation Coefficient was used to verify construct validity (r =.49) and inter-rater reliability (r =.81). The Cronbach Coefficient Alpha, which was used to determine internal consistency of each item, yielded strong positive results for the PLST. The outcomes of this study will be of particular interest to curriculum developers and classroom teachers

  12. Recent achievements on polyanion-type compounds for sodium-ion batteries: Syntheses, crystal chemistry and electrochemical performance

    Science.gov (United States)

    Guo, Sheng-Ping; Li, Jia-Chuang; Xu, Qian-Ting; Ma, Ze; Xue, Huai-Guo

    2017-09-01

    In the past several years, many efforts have been made to develop polyanion-type cathode materials for sodium ion batteries by chemists and material scientists. These materials are one of the main types of promising cathodes though the studies are still in their infancy. This paper reviews almost all the important advances of polyanion-type cathodes on their syntheses, crystal structures, morphologies, electrochemical performance and Na redox mechanisms. It specifically focuses on their crystal chemistry and electrochemical behaviors. The contents are divided into several categories according to their chemical compositions. After introduction of the synthetic methods, phosphates (ortho-, pyro- and fluoro-), silicates, sulfates, and mixed anions type cathodes are summarized and discussed successively.

  13. Stagnation point flow towards nonlinear stretching surface with Cattaneo-Christov heat flux

    Science.gov (United States)

    Hayat, T.; Zubair, M.; Ayub, M.; Waqas, M.; Alsaedi, A.

    2016-10-01

    Here the influence of the non-Fourier heat flux in a two-dimensional (2D) stagnation point flow of Eyring-Powell liquid towards a nonlinear stretched surface is reported. The stretching surface is of variable thickness. Thermal conductivity of fluid is taken temperature-dependent. Ordinary differential systems are obtained through the implementation of meaningful transformations. The reduced non-dimensional expressions are solved for the convergent series solutions. Convergence interval is obtained for the computed solutions. Graphical results are displayed and analyzed in detail for the velocity, temperature and skin friction coefficient. The obtained results reveal that the temperature gradient enhances when the thermal relaxation parameter is increased.

  14. Off-centered stagnation point flow of a couple stress fluid towards a rotating disk.

    Science.gov (United States)

    Khan, Najeeb Alam; Riaz, Fatima

    2014-01-01

    An investigation has been made to study the off-centered stagnation flow of a couple stress fluid over a rotating disk. The model developed for the governing problem in the form of partial differential equations has been converted to ordinary differential equations with the use of suitable similarity transformation. The analytical approximation has been made with the most promising analytical approach, homotopy analysis method (HAM). The convergence region of the obtained solution is determined and plotted. The effects of couple stress and nondimensional parameters have been observed on the flows of couple stress fluid. Also comparison has been made with the Newtonian fluid as the special case of considered problem.

  15. Heat transfer in MHD unsteady stagnation point flow with variable wall temperature

    Digital Repository Service at National Institute of Oceanography (India)

    Soundalgekar, V.M.; Murty, T.V.R.; Takhar, H.S.

    of free-stream oscillations cn the flow of an incompressible viscous fluid past a semi-infinite boay. The small amplituae pheno menon was studied. The unsteady motion of a semi-infinite plate in a viscous fluid was also studied by Cheng and ElJiott 2.... In section2~the mathematical analysis is considered and in section 3 the conclusions are set onto REAT TRANSFER 385 2. MATHBMATICAL ANALYSIS MHO flow of an incompressible viscous fluid near a forward stagnation point of a blunt-nosed two dimensional body...

  16. Unsteady stagnation-point heat transfer during passage of a concentrated vortex

    Science.gov (United States)

    Rigby, David L.; Rae, William J.

    1989-06-01

    The unsteady boundary layer due to a single rectilinear vortex filament approaching a two-dimensional stagnation point is investigated. The unsteady boundary-layer equations are solved by an alternating-direction-implicit finite-difference method. Two mechanisms which cause fluctuations in heat transfer are the unsteady velocity field in the boundary layer and secondly, the unsteady total temperature at the edge of the boundary layer. The relative importance of these mechanisms is dependent upon the total temperature fluctuations relative to the imposed temperature difference.

  17. Laminar flow at a three-dimensional stagnation point with large rates of injection

    Science.gov (United States)

    Libby, P. A.

    1976-01-01

    Exact calculations of the titled flow are presented and compared to the predictions of an asymptotic analysis for large rates of injection. The inner layer of the boundary layer is found to involve outflow in both orthogonal directions whether the external flow along the y axis is inward or outward. As a result, the flow at a nearly two-dimensional stagnation point involves drastic changes as a weak outflow changes to a weak inflow. It is also found that the velocity profiles in the two directions in the inner layer are quite different.

  18. Stagnation point flow of an non-Newtonian visco-elastic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Teipel, I. [Univ. of Hannover, Inst. of Mechanics, Hannover (Germany)

    1985-07-01

    In this paper the flow near a two-dimensional stagnation point for a particular non-Newtonian fluid has been studied. Non-Newtonian fluids form a wide class of different materials, which will be used very often in chemical industries. From a practical point of view it is of great importance to obtain some results for example concerning the flow rate and the losses in a tube, the drag and the separation point of a boundary layer flow etc. for such fluids. Therefore it is necessary to assume a particular constitutive equation to calculate various aspects. (author)

  19. MHD stagnation point flow over a stretching cylinder with variable thermal conductivity and joule heating

    Science.gov (United States)

    Jahan, Shah; Sakidin, Hamzah; Nazar, Roslinda Mohd

    2016-11-01

    The behavior of magnetohydrodynamics (MHD) flow of viscous fluid near the stagnation point over a stretching cylinder with variable thermal conductivity is analyzed. Thermal conductivity is assumed to be linearly related with temperature. The joule heating effects due to magnetic field is also encountered here. Analytical solutions are developed for both momentum and energy equations by using the homotopy analysis method (HAM). The variations of different parameters on the velocity and temperature distributions along with the skin friction coefficient and local Nusselt number are displayed graphically. Numerical values for the skin friction coefficient are calculated and discussed

  20. Impact of Entropy Generation on Stagnation-Point Flow of Sutterby Nanofluid: A Numerical Analysis

    Science.gov (United States)

    Azhar, Ehtsham; Iqbal, Z.; Maraj, E. N.

    2016-09-01

    The present article dicusses the computational analysis of entropy generation for the stagnation-point flow of Sutterby nanofluid over a linear stretching plate. The Sutterby fluid is chosen to study the effect for three major classes of non-Newtonian fluids, i.e. pseudoplastic, Newtonian, and dilatant. The effects of pertinent physical parameters are examined under the approximation of boundary layer. The system of coupled nonlinear partial differential equations is simplified by incorporating suitable similarity transformation into a system of non-linear-coupled ordinary differential equations. Entropy generation analysis is conducted numerically, and the results are displayed through graphs and tables. Significant findings are listed in the closing remarks.

  1. Hypoxia, overnight wear, and tear stagnation effects on the corneal epithelium: data and proposed model.

    Science.gov (United States)

    Lin, Meng C; Polse, Kenneth A

    2007-11-01

    : To explore the possible mechanisms that may lead to overnight contact lens-associated corneal morbidity by examining data from several corneal epithelial permeability experiments obtained under different environmental and lens fitting paradigms. : Epithelial permeability was assessed by using fluorometry to determine the fluorescein penetration rate from the tear film into the corneal stroma. Changes in this rate provide an index of the corneal epithelial status; increased permeability leads to decreased barrier function. : Hypoxia and tear stagnation during overnight lens wear play a significant role in altering the corneal epithelial barrier function (Povernight contact lens wear.

  2. Growth or stagnation in pre-industrial Britain? A revealed income growth approach

    DEFF Research Database (Denmark)

    Groth, Christian; Persson, Karl Gunnar

    2016-01-01

    The extent of growth in pre-industrial Europe in general and in Britain in particular has attracted intense scholarly focus. Growth or Malthusian stagnation? No consensus has evolved. Reconstructions of national income from 1300 and up to the Industrial Revolution come to opposing conclusions...... and so do econometric studies. Applying Engels’ law, we suggest a new approach in which income growth is revealed by changes in occupational structure. Data needed for this approach are less contested than the wage and output series used in the existing literature. We find that pre-industrial Britain...

  3. Main technical options of the Jules Horowitz reactor project to achieve high flux performances and high safety level

    Energy Technology Data Exchange (ETDEWEB)

    Ballagny, A.; Bergamaschi, Y.; Bouilloux, Y.; Bravo, X.; Guigon, B.; Rommens, M.; Tremodeux, P. [CEA Cadarache, Dir. de l' Energie Nucleaire DEN, 13 - Saint-Paul-lez-Durance (France)]|[CEA Saclay Dir. de l' Energie Nucleaire DEN, 91 - Gif sur Yvette (France)

    2003-07-01

    Since the shutdown of the SILOE reactor in 1997, the OSIRIS reactor has ensured the needs regarding technological irradiation at CEA including those of its industrial partners and customers. The Jules Horowitz Reactor will replace it and will offer a quite larger experimental field. It has the ambition to provide the necessary nuclear data and to maintain a fission research capability in Europe after 2010. The Jules Horowitz Reactor will represent a significant step in terms of performances and experimental capabilities. This paper will present the main design option resulting from the preliminary studies. The choice of the specific power around 600 kW/I for the reference core configuration is a key decision to ensure the required flux level. Consequently many choices have to be made regarding the materials used in the core and the fuel element design. These involve many specific qualifications including codes validation. The main safety options are based on: - A safety approach based upon the defence-in-depth principle. - A strategy of generic approaches to assess experimental risks in the facility. - Internal events analysis taking into account risks linked to reactor and experiments (e.g., radioactive source-term). - Systematic consideration of external hazards (e.g., earthquake, airplane crash) and internal hazards. - Design of containment to manage and mitigate a severe reactor accident (consideration of 'BORAX' accident, according to french safety practice for MTRs, beyond design basis reactivity insertion accident, involving core melting and core destruction phenomena). (authors)

  4. Achieving High Performance With TCP Over 40 GbE on NUMA Architectures for CMS Data Acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Bawej, Tomasz; et al.

    2014-01-01

    TCP and the socket abstraction have barely changed over the last two decades, but at the network layer there has been a giant leap from a few megabits to 100 gigabits in bandwidth. At the same time, CPU architectures have evolved into the multicore era and applications are expected to make full use of all available resources. Applications in the data acquisition domain based on the standard socket library running in a Non-Uniform Memory Access (NUMA) architecture are unable to reach full efficiency and scalability without the software being adequately aware about the IRQ (Interrupt Request), CPU and memory affinities. During the first long shutdown of LHC, the CMS DAQ system is going to be upgraded for operation from 2015 onwards and a new software component has been designed and developed in the CMS online framework for transferring data with sockets. This software attempts to wrap the low-level socket library to ease higher-level programming with an API based on an asynchronous event driven model similar to the DAT uDAPL API. It is an event-based application with NUMA optimizations, that allows for a high throughput of data across a large distributed system. This paper describes the architecture, the technologies involved and the performance measurements of the software in the context of the CMS distributed event building.

  5. The major upgrade of the MAGIC telescopes, Part II: The achieved physics performance using the Crab Nebula observations

    CERN Document Server

    Aleksic, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barcelo, M; Barrio, J A; Gonzalez, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Bitossi, M; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Cecchi, R; Colin, P; Colombo, E; Contreras, J L; Corti, D; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Wilhelmi, E de Ona; Mendez, C Delgado; Dettlaff, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fidalgo, D; Fink, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; Lopez, R J Garcia; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giavitto, G; Godinovic, N; Munoz, A Gonzalez; Gozzini, S R; Haberer, W; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Illa, J M; Kadenius, V; Kellermann, H; Knoetig, M L; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lemus, J L; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; Lopez, M; Lopez-Coto, R; Lopez-Oramas, A; Lorca, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martinez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Negrello, M; Neustroev, V; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribo, M; Rico, J; Garcia, J Rodriguez; Rugamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schlammer, J; Schmidl, S; Schweizer, T; Shore, S N; Sillanpaa, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Tejedor, L A; Temnikov, P; Terzic, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Vogler, P; Wetteskind, H; Will, M; Zanin, R; IFAE,; UAB, Campus; Bellaterra, E-08193; Spain,; di Udine, Universita; Trieste, INFN; Udine, I-33100; Italy,; Astrophysics, INAF National Institute for; Rome, I-00136; di Siena, Universita; Pisa, INFN; Siena, I-53100; Institute, Rudjer Boskovic; Rijeka, University of; Split, University of; Zagreb, HR-10000; Croatia,; Physik, Max-Planck-Institut fur; Munchen, D-80805; Germany,; Complutense, Universidad; Madrid, E-28040; de Canarias, Inst de Astrofisica; La Laguna, E-38200; Tenerife,; Lodz, University of; Lodz, PL-90236; Poland,; Elektronen-Synchrotron, Deutsches; Zeuthen, D-15738; Zurich, ETH; Zurich, CH-8093; Switzerland,; Wurzburg, Universitat; Wurzburg, D-97074; Energeticas, Centro de Investigaciones; Tecnologicas, Medioambientales y; Sciences, Institute of Space; Barcelona, E-08193; di Padova, Universita; INFN,; Padova, I-35131; Dortmund, Technische Universitat; Dortmund, D-44221; Radiacions, Unitat de Fisica de les; de Fisica, Departament; CERES-IEEC,; de Barcelona, Universitat Autonoma; de Barcelona, Universitat; ICC,; IEEC-UB,; Barcelona, E-08028; Physics, Division of; Astronomy,; University, Kyoto; Japan,; Observatory, Tuorla; Turku, University of; Physics, Department of; Oulu, University of; Finland,; Research, Inst for Nucl; Energy, Nucl; Sofia, BG-1784; Bulgaria,; di Pisa, Universita; Pisa, I-56126; ICREA,; Insubria, Universita dell; Bicocca, INFN Milano; Como,; Como, I-22100; Observatory, European Gravitational; Macerata, I-56021 S Stefano a; Siena, INFN; at, now; :,; Center, NASA Goddard Space Flight; Greenbelt,; 20771, MD; USA,; Physics, Department of; Astronomy, Department of; Maryland, University of; Park, College; 20742, MD; de Lausanne, now at Ecole polytechnique federale; Lausanne,; Teilchenphysik, Now at Institut fur Astro- und; Innsbruck, Leopold-Franzens- Universitat; Innsbruck, A-6020; Austria,; deceased,; ESO, now at Finnish Centre for Astronomy with; Turku,; Division, now at Astrophysics Science; Centre, Bhabha Atomic Research; 400085, Mumbai; India,; INAF-Trieste, also at

    2014-01-01

    MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the MAGIC-I camera and its trigger system, as well as the upgrade of the readout system of both telescopes. We use observations of the Crab Nebula taken at low and medium zenith angles to assess the key performance parameters of the MAGIC stereo system. For low zenith observations the trigger threshold of the MAGIC telescopes is about 50GeV. The integral sensitivity for sources with Crab Nebula-like spectrum above 220GeV is (0.66+/-0.03)% of Crab Nebula flux in 50 h of observations. The angular resolution at those energies is < 0.07 degree, while the energy resolution is 16%. We also re-evaluate the effect of the systematic uncertainty on the data taken with the MAGIC telescopes after the upgrade. We estimate that the systematic uncertainties can be divided in following components: < 15% in energy scale...

  6. Stagnation point flow and heat transfer on a thin porous sheet: Applications to flow dynamics of the circulatory system

    Science.gov (United States)

    Misra, J. C.; Sinha, A.; Mallick, B.

    2017-03-01

    The paper is concerned with the modeling and analysis of stagnation point flow and heat transfer on a thin porous sheet under the action of an induced magnetic field. The fluid is considered to be incompressible viscous and electrically conducting. The study is motivated towards exploring some interesting phenomena in the micro-circulatory system. Heat transfer is considered to be governed by the heat equation. In order to take care of the induced magnetism that affects the flow process, the flow equations are coupled with magnetic field variables. The analysis has been performed under the purview of the boundary layer theory, together with the use of similarity transformation. The transformed equations are solved by developing an appropriate numerical method. Numerical results have been computed for a typical situation of the fluid in motion. The results are displayed graphically/in tabular form, which depict the distribution of velocity and temperature under the action of the induced magnetic field and permeability of the porous sheet. The study shows that the flow of the fluid reduces, as the strength of the induced magnetic field increases. However, the reduction in velocity is accompanied by an enhancement of the temperature field.

  7. MHD Stagnation-Point Flow of Casson Fluid and Heat Transfer over a Stretching Sheet with Thermal Radiation

    Directory of Open Access Journals (Sweden)

    Krishnendu Bhattacharyya

    2013-01-01

    Full Text Available The two-dimensional magnetohydrodynamic (MHD stagnation-point flow of electrically conducting non-Newtonian Casson fluid and heat transfer towards a stretching sheet have been considered. The effect of thermal radiation is also investigated. Implementing similarity transformations, the governing momentum, and energy equations are transformed to self-similar nonlinear ODEs and numerical computations are performed to solve those. The investigation reveals many important aspects of flow and heat transfer. If velocity ratio parameter (B and magnetic parameter (M increase, then the velocity boundary layer thickness becomes thinner. On the other hand, for Casson fluid it is found that the velocity boundary layer thickness is larger compared to that of Newtonian fluid. The magnitude of wall skin-friction coefficient reduces with Casson parameter (β. The velocity ratio parameter, Casson parameter, and magnetic parameter also have major effects on temperature distribution. The heat transfer rate is enhanced with increasing values of velocity ratio parameter. The rate of heat transfer is enhanced with increasing magnetic parameter M for B > 1 and it decreases with M for B < 1. Moreover, the presence of thermal radiation reduces temperature and thermal boundary layer thickness.

  8. Impedance spectroscopy and structural properties of the perovskite-like Sn(Ba,Sr)O{sub 3} stagnate

    Energy Technology Data Exchange (ETDEWEB)

    Cuervo Farfan, J. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia); Ciencias Basicas, Universidad Manuela Beltran, Bogota DC (Colombia); Olaya, J.J. [Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de Colombia, Bogota DC (Colombia); Vera Lopez, E. [Grupo de Superficies, Electroquimica y Corrosion, Universidad Pedagogica y Tecnologica de Colombia, Tunja (Colombia); Landinez Tellez, D.A. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia)

    2012-08-15

    An exhaustive study of structural, electrical and transport properties on the perovskite stagnate Sn(Ba,Sr)O{sub 3} was performed. Samples of SnBa{sub 1-x}Sr{sub x}O{sub 3} with 0{<=}x{<=}1.00 were prepared by the solid state reaction method. The crystallographic structure was studied by X-ray diffraction experiments and Rietveld refinement using the GSAS code. Results reveal the material synthesized in a cubic structure (space group Pm3-bar m, no. 221) for 0{<=}x{<=}0.50 and in an orthorhombic (space group Pnma, no. 62) for x>0.50. The approximate grain size was found from experiments' Scanning Electron Microscopy. The electric response was studied by the Impedance Spectroscopy technique from 10.0 mHz up to 0,10 MHz. Electric polarization measurements for SnSrO{sub 3} and SnBaO{sub 3} were determined through curves of polarization as a function of applied electric field, which reveal the ferroelectric character of the material. From the saturation polarization the dielectric constants of materials were calculated.

  9. Preliminary results of a study of the relationship between free stream turbulence and stagnation region heat transfer

    Science.gov (United States)

    Vanfossen, G. J., Jr.; Simoneau, R. J.

    1985-01-01

    The mechanism that causes free stream turbulence to increase heat transfer in the stagnation region of turbine vanes and blades was studied. The work is being conducted in a wind tunnel at atmospheric conditions to facilitate measurements of turbulence and heat transfer. The model size is scaled up to simulate Reynolds numbers (based on leading edge diameter) that are to be expected on a turbine blade leading edge. Reynolds numbers from 13,000 to 177,000 were run in the present tests. Spanwise averaged heat transfer measurement with high and low turbulence were made with rough and smooth surface stagnation regions. Results of these measurements show that the boundary layer remains laminar in character even in the presence of free stream turbulence at the Reynolds numbers tested. If roughness is added the boundary layer becomes transitional as evidenced by the heat transfer increase with increasing distance from the stagnation line. Hot wire measurements near the stagnation region downstream of an array of parallel wires have shown that vorticity in the form of mean velocity gradients is amplified as flow approaches the stagnation region.

  10. Hydrodynamic aspects of premixed flame stripes in two-dimensional stagnation-point flows

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.; Sohrab, S.H. [Northwestern Univ., Evanston, IL (United States). Dept. of Mechanical Engineering

    1995-06-01

    The behavior of cellular premixed flames of rich butane-air in the two-dimensional stagnation-point flow configuration has been investigated. It is found that the stretching of the cellular flame results in the alignment f the ridge (extinction) and the trough (combustion) zones of the individual cells such as to form a series of parallel flame stripes. The number of flame stripes as a function of the equivalence ratio for three different mean velocities at the nozzle have been determined. Through the introduction of a generalized form of the stream function periodic velocity fields are obtained as the exact solutions of the Euler equation for the nonreactive finite-jet two-dimensional stagnation flow. The predicted periodic velocity profiles are confirmed by the experimental observation of the streamlines in nonreactive flow made visible by laser-sheet lighting. The observed average size of the flame stripes is found to be in good agreement with the predicted value. Similar periodic velocity profiles are also obtained for the viscous flow within the laminar boundary layer by treatment of the unsteady vorticity equation first described by Taylor. The results support an earlier prediction by Williams that cellular flame structures that are affected mainly by diffusive-thermal phenomena may in fact be initiated by the hydrodynamic instability.

  11. Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier

    Institute of Scientific and Technical Information of China (English)

    Miao Yu; Zongzheng Chen; Cheng Xiang; Bo Liu; Handi Xie; Kairong Qin

    2016-01-01

    Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the rela-tionship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier. The microfluidic device overcomes the weakness of the tra-ditional ones, which have been only based upon either stag-nation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addi-tion, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system. It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and con-veniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments.

  12. Boundary layer flow near a stagnation point on a permeable vertical surface immersed in a nanofluid

    Science.gov (United States)

    Othman, Noor Adila; Yacob, Nor Azizah; Bachok, Norfifah; Ramli, Nazirah; Ishak, Anuar

    2015-10-01

    A steady mixed convection boundary layer flow near a stagnation point on a permeable vertical surface immersed in a nanofluid is investigated. The velocity of the external flow is assumed to vary linearly with the distance from the stagnation-point. The governing partial differential equations are first transformed into ordinary differential equations, before being solved numerically using the Keller box method with the help of MATLAB software. The effects of physical parameters such as the suction/injection parameter, Brownian motion parameter, thermophoresis parameter and Lewis number on the heat and mass transfer rate at the surface as well as the temperature and concentration profiles are analyzed and discussed. Both assisting and opposing flows are considered. It is found that, increasing the thermophoresis parameter, Brownian motion parameter and Lewis number are to decrease the heat transfer rate at the surface, but on the other hand increase the mass transfer rate at the surface for both assisting and opposing flows. In addition, increasing suction parameter tends to increase the heat transfer rate at the surface. However, the opposite behavior occurs for the effect of mass transfer rate at the surface.

  13. Study of magnetic fields and current in the Z pinch at stagnation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, V. V.; Anderson, A. A.; Astanovitskiy, A. L.; Nalajala, V.; Dmitriev, O. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Papp, D. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); ELI-ALPS, ELI-Hu Nkft., H-6720 Szeged (Hungary)

    2015-09-15

    The structure of magnetic fields in wire-array Z pinches at stagnation was studied using a Faraday rotation diagnostic at the wavelength of 266 nm. The electron plasma density and the Faraday rotation angle in plasma were calculated from images of the three-channel polarimeter. The magnetic field was reconstructed with Abel transform, and the current was estimated using a simple model. Several shots with wire-array Z pinches at 0.5–1.5 MA were analyzed. The strength of the magnetic field measured in plasma of the stagnated pinch was in the range of 1–2 MG. The magnetic field and current profile in plasma near the neck on the pinch were reconstructed, and the size of the current-carrying plasma was estimated. It was found that current flowed in the large-size trailing plasma near the dense neck. Measurements of the magnetic field near the bulge on the pinch also showed current in trailing plasma. A distribution of current in the large-size trailing plasma can prevent the formation of multi-MG fields in the Z pinch.

  14. Detection of flow separation and stagnation points using artificial hair sensors

    Science.gov (United States)

    Phillips, D. M.; Ray, C. W.; Hagen, B. J.; Su, W.; Baur, J. W.; Reich, G. W.

    2015-11-01

    Recent interest in fly-by-feel approaches for aircraft control has motivated the development of novel sensors for use in aerial systems. Artificial hair sensors (AHSs) are one type of device that promise to fill a unique niche in the sensory suite for aerial systems. In this work, we investigate the capability of an AHS based on structural glass fibers to directly identify flow stagnation and separation points on a cylindrical domain in a steady flow. The glass fibers are functionalized with a radially aligned carbon nanotube (CNT) forest and elicit a piezoresistive response as the CNT forest impinges on electrodes in a micropore when the hair is deflected due to viscous drag forces. Particle image velocimetry is used to measure the flow field allowing for the resulting moment and force acting on the hair to be correlated with the electrical response. It is demonstrated that the AHS provides estimates for the locations of both the stagnation and separation in steady flow. From this, a simulation of a heading estimation is presented to demonstrate a potential application for hair sensors. These results motivate the construction of large arrays of hair sensors for imaging and resolving flow structures in real time.

  15. Performance-based tests versus behavioral ratings in the assessment of executive functioning in preschoolers: associations with ADHD symptoms and reading achievement.

    Directory of Open Access Journals (Sweden)

    Ana eMiranda

    2015-04-01

    Full Text Available The early assessment of the executive processes using ecologically valid instruments is essential for identifying deficits and planning actions to deal with possible adverse consequences. The present study has two different objectives. The first objective is to analyze the relationship between preschoolers’ performance on tests of Working Memory and Inhibition and parents’ and teachers’ ratings of these executive functions (EF using the Behavior Rating Inventory of Executive Function (BRIEF. The second objective consists of studying the predictive value of the different EF measures (performance-based test and rating scales on Inattention and Hyperactivity/Impulsivity behaviors and on indicators of word reading performance. The participants in the study were 209 children in the last year of preschool, their teachers and their families. Performance-based tests of Working Memory and Inhibition were administered, as well as word reading measures (accuracy and speed. The parents and teachers filled out rating scales of the EF and typical behaviors of ADHD symptomatology. Moderate correlation values were found between the different EF assessments procedures, although the results varied depending on the different domains. Metacognition index from the BRIEF presented stronger correlations with verbal working memory tests than with inhibition tests. Both the rating scales and the performance-based tests were significant predictors of Inattention and Hyperactivity/Impulsivity behaviors and the reading achievement measures. However, the BRIEF explained a greater percentage of variance in the case of the ADHD symptomatology, while the performance-based tests explained reading achievement to a greater degree. The implications of the findings for research and clinical practice are discussed.

  16. The Role of Lithium Conditioning in Achieving High Performance, Long Pulse H-mode Discharges in the NSTX and EAST Devices

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, Rajesh [PPPL; Mansfield, D. K. [PPPL; Gong, X. Z. [IPPCAS; Sun, Z. [IPPCAS; Bell, M. G. [PPPL

    2014-10-01

    In this paper, the role of lithium wall conditioning on the achievement of high performance, long pulse discharges in the National Spherical Torus Experiment (NSTX) and the Experimental Advanced Superconducting Tokamak (EAST) is documented. Common observations include recycling reduction and elimination of ELMs. In NSTX, lithium conditioning typically resulted in ELM-free operation with impurity accumulation, which was ameliorated e.g. with pulsed 3D fields to trigger controlled ELMs. Active lithium conditioning in EAST discharges has overcome this problem, producing an ELM-free Hmode with controlled density and impurities.

  17. MHD stagnation point flow toward a linearly-stretching thermally-insulated sheet with induced magnetic field

    CERN Document Server

    El-Mistikawy, Tarek M A

    2016-01-01

    The equations governing the magnetohydrodynamic stagnation point flow toward a non-conducting, thermally insulated, nonporous, linearly stretching sheet are cast in a self similar form. Consistent boundary conditions on the velocity, magnetic field and temperature are invoked. The flow problem involves three parameters- the magnetic Prandtl number, the magnetic interaction number, and the ratio of the stretching rate to the strength of the stagnation point flow. The energy equation includes viscous dissipation and Joule heating, and introduces the Prandtl number as a fourth parameter. Numerical solutions are obtained and sample results are presented.

  18. Preliminary results of a study of the relationship between free-stream turbulence and stagnation region heat transfer

    Science.gov (United States)

    Vanfossen, G. J., Jr.; Simoneau, R. J.

    1985-01-01

    Preliminary results of a study to investigate the relationship between free stream turbulence and heat transfer augmentation in the stagnation region is presented. The effects of free stream turbulence and surface roughness on spanwise averaged heat transfer were investigated. Turbulence was measured upstream of a cylinder placed in the wake of an array of parallel wires that were perpendicular to the cylinder axis. Finally, flow visualization and thermal visualization techniques were combined to show the relationship between vortices in the stagnation region and spanwise variations in heat transfer.

  19. Unravelling the correlation between the aspect ratio of nanotubular structures and their electrochemical performance to achieve high-rate and long-life lithium-ion batteries.

    Science.gov (United States)

    Tang, Yuxin; Zhang, Yanyan; Deng, Jiyang; Qi, Dianpeng; Leow, Wan Ru; Wei, Jiaqi; Yin, Shengyan; Dong, Zhili; Yazami, Rachid; Chen, Zhong; Chen, Xiaodong

    2014-12-01

    The fundamental understanding of the relationship between the nanostructure of an electrode and its electrochemical performance is crucial for achieving high-performance lithium-ion batteries (LIBs). In this work, the relationship between the nanotubular aspect ratio and electrochemical performance of LIBs is elucidated for the first time. The stirring hydrothermal method was used to control the aspect ratio of viscous titanate nanotubes, which were used to fabricate additive-free TiO2 -based electrode materials. We found that the battery performance at high charging/discharging rates is dramatically boosted when the aspect ratio is increased, due to the optimization of electronic/ionic transport properties within the electrode materials. The proof-of-concept LIBs comprising nanotubes with an aspect ratio of 265 can retain more than 86 % of their initial capacity over 6000 cycles at a high rate of 30 C. Such devices with supercapacitor-like rate performance and battery-like capacity herald a new paradigm for energy storage systems.

  20. Academic Momentum at University/College: Exploring the Roles of Prior Learning, Life Experience, and Ongoing Performance in Academic Achievement across Time

    Science.gov (United States)

    Martin, Andrew J.; Wilson, Rachel; Liem, Gregory Arief D.; Ginns, Paul

    2014-01-01

    In the context of "academic momentum," a longitudinal study of university students (N = 904) showed high school achievement and ongoing university achievement predicted subsequent achievement through university. However, the impact of high school achievement diminished, while additive effects of ongoing university achievement continued.…

  1. The Classroom Performance System (CPS): Effects on student participation, attendance, and achievement in multicultural anatomy and physiology classes at South Texas College

    Science.gov (United States)

    Termos, Mohamad Hani

    2011-12-01

    The Classroom Performance System (CPS) is an instructional technology tool that increases student performance and addresses different learning styles. Instructional technologies are used to promote active learning; however, student embarrassment issue in a multicultural setting is not addressed. This study assessed the effect of the CPS on student participation, attendance, and achievement in multicultural college-level anatomy and physiology classes at South Texas College, where the first spoken language is not English. Quantitative method and quasi-experimental design were employed and comparative statistic methods and pre-post tests were used to collect the data. Participants were college students and sections of study were selected by convenient sampling. Participation was 100% during most of the lectures held and participation rate did not strike above 68% in control group. Attendance was significantly higher in CPS sections than the control group as shown by t-tests. Experimental sections had a higher increase in the pre-post test scores and student averages on lecture exams increased at a higher rate as compared to the control group. Therefore, the CPS increased student participation, attendance, and achievement in multicultural anatomy and physiology classes. The CPS can be studied in other settings where the first spoken language is English or in other programs, such as special education programs. Additionally, other variables can be studied and other methodologies can be employed.

  2. The Augmented Performer and the Performative Augmentation

    DEFF Research Database (Denmark)

    Kallionpaa, Maria; Gasselseder, Hans-Peter

    2016-01-01

    Composers, performers, and listeners usually regard musical compositions as unchangeable entities, which limits the composition techniques and decreases the originality of performers ́ interpretations, thus leading to a stagnation of classical music culture. The significance and possibilities of ...... help to widen the horizons of classical music. Developing new innovative tools and methodologies would also benefit game designers and music educators.......Composers, performers, and listeners usually regard musical compositions as unchangeable entities, which limits the composition techniques and decreases the originality of performers ́ interpretations, thus leading to a stagnation of classical music culture. The significance and possibilities...... of interactive music systems have been widely recognised in the context of modern computer games. The concept of procedural music challenges the idea of a composition as a fixed formula. Similar to a computer game, a music score based on such techniques can take a plethora of unpredictable turns depending...

  3. Radiation Effects on MHD Stagnation-Point Flow in a Nanofluid

    Directory of Open Access Journals (Sweden)

    Mohammad Eftekhari Yazdi

    2013-05-01

    Full Text Available In this study, the two-dimensional Magnetohydrodynamic (MHD boundary layer of stagnation-point flow in a nanofluid in the presence of thermal radiation is investigated. Using a similarity transform, the Navier-Stokes equations are reduced to a set of nonlinear ordinary differential equations. The similarity equations are solved numerically for three types of nanoparticles, namely copper (Cu, alumina (Al2O3 and titania (TiO2 in water as the base fluid. The skin-friction coefficient and Nusselt number as well as the velocity and temperature profiles for some values of the governing parameters are presented graphically and discussed. Effects of the nanoparticle volume fraction on the flow and heat transfer characteristics are thoroughly examined.

  4. Melting heat transfer in stagnation point flow of carbon nanotubes towards variable thickness surface

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2016-01-01

    Full Text Available This work concentrates on the mathematical modeling for stagnation point flow of nanofluids over an impermeable stretching sheet with variable thickness. Carbon nanotubes [single-wall carbon nanotubes (SWCNTs and multi-wall carbon nanotubes (MWCNTs] as the nanoparticles are utilized. Water and kerosene oil are taken as the base fluids. Heat transfer through melting effect is discussed. Transformation procedure is adapted to obtain the non-linear ordinary differential equations from the fundamental laws of mass, linear momentum and energy. The optimal values of convergence control parameters and corresponding individual and total residual errors for SWCNTs and MWCNTs are computed by means of homotopy analysis method (HAM based BVPh 2.0. Characteristics of different involved parameters on the velocity, temperature, skin friction coefficient and Nusselt number are discussed. Higher velocity profile is observed for wall thickness parameter in case of water carbon nanotubes when compared with the kerosene oil carbon nanotubes.

  5. Interaction of Magnetic Field and Nonlinear Convection in the Stagnation Point Flow over a Shrinking Sheet

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    2016-01-01

    Full Text Available The steady two-dimensional boundary layer stagnation point flow due to a shrinking sheet is analyzed. The combined effects of magnetic field and nonlinear convection are taken into account. The governing equations for the flow are modeled and then simplified using the similarity transformation and boundary layer approach. The numerical solution of the reduced equations is obtained by the second-order finite difference scheme also known as Keller box method. The influence of the pertinent parameters of the problem on velocity and temperature profiles, skin friction, and sheet temperature gradient are presented through the graphs and tables and discussed. The magnetic field and nonlinear convection parameters significantly enhance the solution range.

  6. Steady Stagnation Point Flow and Heat Transfer Over a Shrinking Sheet with Induced Magnetic Field

    Directory of Open Access Journals (Sweden)

    Aniruddha Sinha

    2014-01-01

    Full Text Available The problem of the steady magnetohydrodynamic (MHD stagnation-point flow of an incompressible, viscous and electrically conducting fluid over a shrinking sheet is studied. The effects of an induced magnetic field and thermal radiation are taken into account. Velocity and thermal slip conditions have also been incorporated in the study. The nonlinear partial differential equations are transformed into ordinary differential equations via the similarity transformation. The transformed boundary layer equations are solved numerically using Newton’s linearization method. Computational results for the variation in velocity, temperature, skin-friction co-efficient and Nusselt number are presented graphically and in tabular form. Study reveals that the surface velocity gradient and heat transfer are enhanced by decreasing magnetic parameter.

  7. Dual solutions in MHD stagnation-point flow of Prandtl fluid impinging on shrinking sheet

    Institute of Scientific and Technical Information of China (English)

    N.S.AKBAR; Z.H.KHAN; R.U.HAQ; S.NADEEM

    2014-01-01

    The present article investigates the dual nature of the solution of the magneto-hydrodynamic (MHD) stagnation-point flow of a Prandtl fluid model towards a shrinking surface. The self-similar nonlinear ordinary differential equations are solved numerically by the shooting method. It is found that the dual solutions of the flow exist for cer-tain values of the velocity ratio parameter. The special case of the first branch solutions (the classical Newtonian fluid model) is compared with the present numerical results of stretching flow. The results are found to be in good agreement. It is also shown that the boundary layer thickness for the second solution is thicker than that for the first solution.

  8. MHD stagnation point flow of Carreau fluid toward a permeable shrinking sheet: Dual solutions

    Directory of Open Access Journals (Sweden)

    N.S. Akbar

    2014-12-01

    Full Text Available Present analysis is carried out to study the two-dimensional stagnation-point flow of an in-compressible Carreau fluid toward a shrinking surface. The formulation of the Carreau fluid model has been developed first time for boundary layer problem of shrinking sheet and the governing partial differential equations are rehabilitated into ordinary differential equations using similarity transformations. The simplified nonlinear boundary value problem is solved by Runge-Kutta method after converting into the system of initial value problem using shooting method. Dual solutions are obtained graphically and results are shown for various parameters involved in the flow equations. Numerical values of skin friction coefficients are also computed.

  9. Stagnation-Point Flow toward a Vertical, Nonlinearly Stretching Sheet with Prescribed Surface Heat Flux

    Directory of Open Access Journals (Sweden)

    Sin Wei Wong

    2013-01-01

    Full Text Available An analysis is carried out to study the steady two-dimensional stagnation-point flow of an incompressible viscous fluid towards a stretching vertical sheet. It is assumed that the sheet is stretched nonlinearly, with prescribed surface heat flux. This problem is governed by three parameters: buoyancy, velocity exponent, and velocity ratio. Both assisting and opposing buoyant flows are considered. The governing partial differential equations are transformed into a system of ordinary differential equations and solved numerically by finite difference Keller-box method. The flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. Dual solutions are found in the opposing buoyant flows, while the solution is unique for the assisting buoyant flows.

  10. Melting heat transfer in boundary layer stagnation-point flow towards a stretching/shrinking sheet

    Energy Technology Data Exchange (ETDEWEB)

    Bachok, Norfifah [Department of Mathematics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Ishak, Anuar [School of Mathematical Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Pop, Ioan, E-mail: popm.ioan@yahoo.co.u [Faculty of Mathematics, University of Cluj, CP 253 (Romania)

    2010-09-06

    An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique.

  11. [Analysis on establishment and affecting factors of qi stagnation and blood stasis rat model].

    Science.gov (United States)

    Wang, Tingting; Jia, Cheng; Chen, Yu; Li, Xin; Cheng, Jiayi

    2012-06-01

    To study on the method for establishing the Qi stagnation and blood stasis rat model and analyze the affecting factors. The orthogonal design was adopted to study the influences of joint stimulations including noise, light, electricity, ice water bath, tail-clamping on model rats. The 'flying spot' method was used to dynamically simulate blood flow velocity in microcirculation. the pressure sensing technology of MOTO was adopted to detect hemorheology-related indicators. And the coagulation method was used to detect blood coagulation-related indicators. Compared with the negative control group, all model groups showed significant reduction in the blood flow velocity in mesenteric microcirculation and increase in the whole blood viscosity at high, medium and low shear rate, the plasma viscosity and the fibrinogen content in four blood coagulation indicators. Noise, light, electricity, tail-clamping, bondage and icewater-bath make significant impact on model rats.

  12. Stagnation point flow of Maxwell fluid towards a permeable surface in the presence of nanopar

    Directory of Open Access Journals (Sweden)

    G.K. Ramesh

    2016-06-01

    Full Text Available Analysis has been carried out to study the stagnation point flow of Maxwell fluid towards a permeable stretching sheet in the presence of nanoparticles. Using suitable transformations, the governing partial differential equations are first converted to ordinary one and then solved numerically by fourth–fifth order Runge–Kutta–Fehlberg method with MAPLE. The flow and heat transfer characteristics are analyzed and discussed for different values of the parameters. Present work reveals that the velocity increases whereas the temperature and concentration decrease with the increase of Maxwell parameter. The thermal and concentration boundary layer thickness decreases with velocity ratio, Lewis number, Prandtl number suction, Brownian motion and thermophoresis parameters. Comparison with known results for Newtonian fluid flow is found an excellent agreement.

  13. Momentum and Heat Transfer in MHD Axisymmetric Stagnation-Point Flow over a Shrinking Sheet

    Directory of Open Access Journals (Sweden)

    T. R. Mahapatra

    2013-01-01

    Full Text Available In this paper we present a mathematical analysis for the magneto hydrodynamic (MHD axi-symmetric stagnation-point flow and heat transfer over a shrinking sheet which shrinks axi-symmetrically in its own plane. The governing partial differential equations along with the boundary conditions are first cast into a dimensionless form and then these equations are solved numerically by shooting technique. Thermal conductivity is assumed to vary linearly with the temperature. Temperature profiles are obtained for two different types of heating process namely (i the sheet with prescribed surface temperature (PST and (ii the sheet with prescribed surface heat flux (PHF. The effects of various physical parameters on the flow and heat transfer characteristics are presented graphically and discussed.

  14. Mixed Convection Unsteady Stagnation-Point Flow towards a Stretching Sheet with Slip Effects

    Directory of Open Access Journals (Sweden)

    Hui Chen

    2014-01-01

    Full Text Available The paper studies the unsteady mixed convection flow of an incompressible viscous fluid about a stagnation point on a stretching sheet in presence of velocity and thermal slips. The governing equations are transformed into the ordinary differential equations by using similarity transformations. The transformed equations are solved numerically by an efficient shooting method. The characteristics of the flow and heat transfer features for governing parameters are analyzed and discussed for both the assisting and opposing flows. It is found that dual solutions exist for certain range of buoyancy parameter λ which again depend on the unsteadiness parameter α and the slip parameters (i.e., δ and γ. The numerical results show that the increase of unsteadiness parameter and the slip effects cause increment in the existence range of similarity solution. The effects of unsteadiness parameter, the velocity ratio parameter, and the velocity and thermal slip parameters on the velocity and temperature distributions are analyzed and discussed.

  15. Unsteady free convection of a stagnation point of attachment on an isothermal surface

    Directory of Open Access Journals (Sweden)

    D. B. Ingham

    1984-01-01

    Full Text Available The time development free convection flow near a three-dimensional stagnation point of attachment on an isothermal surface is studied at large Grashof numbers. A small time solution and an accurate numerical method is described for determining the solution of the time-dependent boundary-layer equations. For a range of values of parameter c, which describes the local geometry, the development of the various physical properties of the flow are calculated and compared with their values at small and large values of time. In another range of values of c the numerical results suggest the development of a singularity in the boundary-layer equations at a finite value of time. An anlysis is presented which is consistent with the numerical results and confirms the presence of this singularity.

  16. Series solutions of stagnation slip flow and heat transfer by the homotopy analysis method

    Institute of Scientific and Technical Information of China (English)

    CHENG Jun; LIAO ShiJun; R. N. MOHAPATRA; K. VAJRAVELU

    2009-01-01

    An analytical approximation for the similarity solutions of the two- and three-dimensional stagnation slip flow and heat transfer is obtained by using the homotopy analysis method. This method is a series expansion method, but it is different from the perturbation technique, because it is independent of small physical parameters at all. Instead, it is based on a continuous mapping in topology so that it is applicable for not only weakly but also strongly nonlinear flow phenomena. Convergent [m,m] homotopy Pade approximants are obtained and compared with the numerical results and the numerical results. The effects of the slip length and the thermal slip constant β on the heat transfer characteristics are investigated and discussed.

  17. Numerical and series solutions for stagnation-point flow of nanofluid over an exponentially stretching sheet.

    Science.gov (United States)

    Mustafa, Meraj; Farooq, Muhammad A; Hayat, Tasawar; Alsaedi, Ahmed

    2013-01-01

    This investigation is concerned with the stagnation-point flow of nanofluid past an exponentially stretching sheet. The presence of Brownian motion and thermophoretic effects yields a coupled nonlinear boundary-value problem (BVP). Similarity transformations are invoked to reduce the partial differential equations into ordinary ones. Local similarity solutions are obtained by homotopy analysis method (HAM), which enables us to investigate the effects of parameters at a fixed location above the sheet. The numerical solutions are also derived using the built-in solver bvp4c of the software MATLAB. The results indicate that temperature and the thermal boundary layer thickness appreciably increase when the Brownian motion and thermophoresis effects are strengthened. Moreover the nanoparticles volume fraction is found to increase when the thermophoretic effect intensifies.

  18. Dual Solutions in Unsteady Stagnation-Point Flow over a Shrinking Sheet

    Institute of Scientific and Technical Information of China (English)

    Krishnendu Bhattacharyya

    2011-01-01

    @@ An analysis is made to study the dual nature of solution of unsteady stagnation-point Sow due to a shrinking sheet.Using similarity transformations, the governing boundary layer equations are transformed into the self-similar nonlinear ordinary differential equations.The transformed equations are solved numerically using a very efficient shooting method.The study reveals the conditions of existence, uniqueness and non-existence of unsteady similarity solution.The dual solutions for velocity distribution exist for certain values of velocity ratio parameter (c/a), and the increment in the unsteadiness parameter A increases the range of cla where solution exists.Also,with increasing A, the skin friction coefficient increases for the first solution and decreases for the second.

  19. Series solutions of stagnation slip flow and heat transfer by the homotopy analysis method

    Institute of Scientific and Technical Information of China (English)

    R.N.MOHAPATRA; K.VAJRAVELU

    2009-01-01

    An analytical approximation for the similarity solutions of the two-and three-dimensional stagnation slip flow and heat transfer is obtained by using the homotopy analysis method. This method is a series expansion method, but it is different from the perturbation technique, because it is independent of small physical parameters at all. Instead, it is based on a continuous mapping in topology so that it is applicable for not only weakly but also strongly nonlinear flow phenomena. Convergent [m,m] homotopy Padé approximants are obtained and compared with the numerical results and the asymptotic approximations. It is found that the homotopy Padé approximants agree well with the numerical results. The effects of the slip length and the thermal slip constant β on the heat transfer characteristics are investigated and discussed.

  20. Manipulating flow separation: sensitivity of stagnation points, separatrix angles and recirculation area to steady actuation

    CERN Document Server

    Boujo, Edouard

    2014-01-01

    A variational technique is used to derive analytical expressions for the sensitivity of several geometric indicators of flow separation to steady actuation. Considering the boundary layer flow above a wall-mounted bump, the six following representative quantities are considered: the locations of the separation point and reattachment point connected by the separatrix, the separation angles at these stagnation points, the backflow area and the recirculation area. For each geometric quantity, linear sensitivity analysis allows us to identify regions which are the most sensitive to volume forcing and wall blowing/suction. Validations against full non-linear Navier-Stokes calculations show excellent agreement for small-amplitude control for all considered indicators. With very resemblant sensitivity maps, the reattachment point, the backflow and recirculation areas are seen to be easily manipulated. In contrast, the upstream separation point and the separatrix angles are seen to remain extremely robust with respec...

  1. MHD stagnation point flow by a permeable stretching cylinder with Soret-Dufour effects

    Institute of Scientific and Technical Information of China (English)

    M Ramzan; M Farooq; T Hayat; A Alsaedi; J Cao

    2015-01-01

    Combined effects of Soret (thermal-diffusion) and Dufour (diffusion-thermo) in MHD stagnation point flow by a permeable stretching cylinder were studied. Analysis was examined in the presence of heat generation/absorption and chemical reaction. The laws of conservation of mass, momentum, energy and concentration are found to lead to the mathematical development of the problem. Suitable transformations were used to convert the nonlinear partial differential equations into the ordinary differential equations. The series solutions of boundary layer equations through momentum, energy and concentration equations were obtained. Convergence of the developed series solutions was discussed via plots and numerical values. The behaviors of different physical parameters on the velocity components, temperature and concentration were obtained. Numerical values of Nusselt number, skin friction and Sherwood number with different parameters were computed and analyzed. It is found that Dufour and Soret numbers result in the enhancement of temperature and concentration distributions, respectively.

  2. Investigations of subterranean microorganisms and their importance for performance assessment of radioactive waste disposal. Results and conclusions achieved during the period 1995 to 1997

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, K. [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology

    1997-11-01

    In 1987, microbiology became a part of the Swedish scientific program for the safe disposal of high level nuclear waste (HLW). The goal of the microbiology sub-program is to understand how subterranean microorganisms will interact with the performance of a future HLW repository. The Swedish research program on subterranean microbiology has mainly been performed at two sites in granitic rock aquifers at depths ranging from 70 m down to 1240 m; the Stripa research mine in the middle of Sweden and the Aespoe hard rock laboratory (HRL) situated on the south eastern coast of Sweden. Some work has also been performed in co-operation with other national or international research groups in Sweden, Canada and at the natural analogue sites in Oklo in Gabon and Maqarin in Jordan. The most recent report in the SKB technical report series on microbiology and performance assessment, SKB-TR--95-10, gave the state of the art regarding microorganisms and their importance for performance assessment. That report is recommended as a source of knowledge about basic microbiology, microbial ecology of subterranean environments and the nuclear waste disposal concept in a microbiological perspective. The present report summarises results and conclusions achieved during the period 1995 to 1997 and is a continuation of SKB TR 95-10. The report is structured as summary which explains and analyses the obtained results and conclusions in a performance assessment perspective. The scientific basis for the summary is an enclosed series of eleven papers of which eight have gone through an international peer review process for publication in international scientific journals and reports and papers published earlier. 413 refs, 56 figs, 39 tabs.

  3. Microbiological tap water profile of a medium-sized building and effect of water stagnation.

    Science.gov (United States)

    Lipphaus, Patrick; Hammes, Frederik; Kötzsch, Stefan; Green, James; Gillespie, Simon; Nocker, Andreas

    2014-01-01

    Whereas microbiological quality of drinking water in water distribution systems is routinely monitored for reasons of legal compliance, microbial numbers in tap water are grossly understudied. Motivated by gross differences in water from private households, we applied in this study flow cytometry as a rapid analytical method to quantify microbial concentrations in water sampled at diverse taps in a medium size research building receiving chlorinated water. Taps differed considerably in frequency of usage and were located in laboratories, bathrooms, and a coffee kitchen. Substantial differences were observed between taps with concentrations (per mL) in the range from 6.29 x 10(3) to 7.74 x 10(5) for total cells and from 1.66 x 10(3) to 4.31 x 10(5) for intact cells. The percentage of intact cells varied between 7% and 96%. Water from taps with very infrequent use showed the highest bacterial numbers and the highest proportions of intact cells. Stagnation tended to increase microbial numbers in water from those taps which were otherwise frequently used. Microbial numbers in other taps that were rarely opened were not affected by stagnation as their water is probably mostly stagnant. For cold water taps, microbial numbers and the percentage of intact cells tended to decline with flushing with the greatest decline for taps used least frequently whereas microbial concentrations in water from hot water taps tended to be somewhat more stable. We conclude that microbiological water quality is mainly determined by building-specific parameters. Tap water profiling can provide valuable insight into plumbing system hygiene and maintenance.

  4. Axisymmetric Stagnation-Point Flow with a General Slip Boundary Condition over a Lubricated Surface

    Institute of Scientific and Technical Information of China (English)

    M. Sajid; K. Mahmood; Z. Abbas

    2012-01-01

    We investigate the axisymmetric stagnation-point flow of a viscous fluid over a lubricated surface by imposing a generalized slip condition at the fluid-fluid interface.The power law non-Newtonian fluid is considered as a lubricant.The lubrication layer is thin and assumed to have a variable thickness.The transformed nonlinear ordinary differential equation governing the flow is linearized using quasilinearization.The method of superposition is adopted to convert the boundary value problem into an initial value problem and the solution is obtained numerically by using the fourth-order RungeKutta method.The results are discussed to see the influence of pertinent parameters.The limiting cases of Navier and no-slip boundary conditions are obtained as the special cases and found to be in excellent agreement with the existing results in the literature.%We investigate the axisymmetric stagnation-point flow of a viscous fluid over a lubricated surface by imposing a generalized slip condition at the fluid-fluid interface. The power law non-Newtonian fluid is considered as a lubricant. The lubrication layer is thin and assumed to have a variable thickness. The transformed nonlinear ordinary differential equation governing the flow is linearized using quasilinearization. The method of superposition is adopted to convert the boundary value problem into an initial value problem and the solution is obtained numerically by using the fourth-order Runge Kutta method. The results arc discussed to see the influence of pertinent parameters. The limiting cases of Navier and no-slip boundary conditions are obtained as the special cases and found to be in excellent agreement with the existing results in the literature.

  5. The stagnation of the Mexican male life expectancy in the first decade of the 21st century

    DEFF Research Database (Denmark)

    Canudas-Romo, Vladimir; García-Guerrero, Víctor Manuel; Echarri-Cánovas, Carlos Javier

    2015-01-01

    OBJECTIVES: In the first decade of the 21st century, the Mexican life expectancy changed from a long trend of increase to stagnation. These changes concur with an increase in deaths by homicides that the country experienced in that decade, and an obesity epidemic that had developed over the last ...

  6. Achieving Standardization

    DEFF Research Database (Denmark)

    Henningsson, Stefan

    2014-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has...

  7. Achieving Standardization

    DEFF Research Database (Denmark)

    Henningsson, Stefan

    2016-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has...

  8. Achieving professionalism

    Directory of Open Access Journals (Sweden)

    R.A.E. Thompson

    1983-09-01

    Full Text Available In approaching the subject of professionalism the author has chosen to focus on the practical aspects rather than the philosophical issues. In so doing an attempt is made to identify criteria which demonstrate the achievement of the essence of professionalism.

  9. Providing critical laboratory results on time, every time to help reduce emergency department length of stay: how our laboratory achieved a Six Sigma level of performance.

    Science.gov (United States)

    Blick, Kenneth E

    2013-08-01

    To develop a fully automated core laboratory, handling samples on a "first in, first out" real-time basis with Lean/Six Sigma management tools. Our primary goal was to provide services to critical care areas, eliminating turnaround time outlier percentage (TAT-OP) as a factor in patient length of stay (LOS). A secondary goal was to achieve a better laboratory return on investment. In 2011, we reached our primary goal when we calculated the TAT-OP distribution and found we had achieved a Six Sigma level of performance, ensuring that our laboratory service can be essentially eliminated as a factor in emergency department patient LOS. We also measured return on investment, showing a productivity improvement of 35%, keeping pace with our increased testing volume. As a result of our Lean process improvements and Six Sigma initiatives, in part through (1) strategic deployment of point-of-care testing and (2) core laboratory total automation with robotics, middleware, and expert system technology, physicians and nurses at the Oklahoma University Medical Center can more effectively deliver lifesaving health care using evidence-based protocols that depend heavily on "on time, every time" laboratory services.

  10. Effects of Gyejibongnyeong-hwan on dysmenorrhea caused by blood stagnation: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Park Jeong-Su

    2012-01-01

    Full Text Available Abstract Background Gyejibongnyeong-hwan (GJBNH is one of the most popular Korean medicine formulas for menstrual pain of dysmenorrhea. The concept of blood stagnation in Korean medicine is considered the main factor of causing abdominal pain, or cramps, during menstrual periods. To treat the symptoms, GJBNH is used to fluidify the stagnated blood and induce the blood flow to be smooth, reducing pain as the result. The purpose of this trial is to identify the efficacy of GJBNH in dysmenorrhea caused by blood stagnation. Methods This study is a multi-centre, randomised, double-blind, controlled trial with two parallel arms: the group taking GJBNH and the group taking placebo. 100 patients (women from age 18 to 35 will be enrolled to the trial. Through randomization 50 patients will be in experiment arm, and the other 50 patients will be in control arm. At the second visit (baseline, all participants who were already screened that they fulfil both the inclusion and the exclusion criteria will be randomised into two groups. Each group will take the intervention three times per day during two menstrual cycles. After the treatment for two cycles, each patient will be followed up during their 3rd, 4th and 5th menstrual cycles. From the screening (Visit 1 through the second follow-up (Visit 6 the entire process will take 25 weeks. Discussion This trial will provide evidence for the effectiveness of GJBNH in treating periodical pain due to dysmenorrhea that is caused by blood stagnation. The primary outcome between the two groups will be measured by changes in the Visual Analogue Score (VAS of pain. The secondary outcome will be measured by the Blood Stagnation Scale, the Short-form McGill questionnaire and the COX menstrual symptom scale. Analysis of covariance (ANCOVA and repeated measured ANOVA will be used to analyze the data analysis. Trial registration Current Controlled Trials: ISRCTN30426947

  11. Is yield increase sufficient to achieve food security in China?

    Science.gov (United States)

    Wei, Xing; Zhang, Zhao; Shi, Peijun; Wang, Pin; Chen, Yi; Song, Xiao; Tao, Fulu

    2015-01-01

    Increasing demand for food, driven by unprecedented population growth and increasing consumption, will keep challenging food security in China. Although cereal yields have substantially improved during the last three decades, whether it will keep thriving to meet the increasing demand is not known yet. Thus, an integrated analysis on the trends of crop yield and cultivated area is essential to better understand current state of food security in China, especially on county scale. So far, yield stagnation has extensively dominated the main cereal-growing areas across China. Rice yield is facing the most severe stagnation that 53.9% counties tracked in the study have stagnated significantly, followed by maize (42.4%) and wheat (41.9%). As another important element for production sustainability, but often neglected is the planted area patterns. It has been further demonstrated that the loss in productive arable land for rice and wheat have dramatically increased the pressure on achieving food security. Not only a great deal of the planted areas have stagnated since 1980, but also collapsed. 48.4% and 54.4% of rice- and wheat-growing counties have lost their cropland areas to varying degrees. Besides, 27.6% and 35.8% of them have retrograded below the level of the 1980s. The combined influence (both loss in yield and area) has determined the crop sustainable production in China to be pessimistic for rice and wheat, and consequently no surprise to find that more than half of counties rank a lower level of production sustainability. Therefore, given the potential yield increase in wheat and maize, as well as substantial area loss of rice and wheat, the possible targeted adaptation measures for both yield and cropping area is required at county scale. Moreover, policies on food trade, alongside advocation of low calorie diets, reducing food loss and waste can help to enhance food security.

  12. The impact of nursing students' chemistry learning performance assessment in Taiwan: competitive versus non-competitive student team achievement division approaches

    Science.gov (United States)

    Wang, Kai-Ping

    2012-07-01

    Purpose: The purpose of this study was to determine the effectiveness of competitive Student Team Achievement Division (STAD), non-competitive STAD, and traditional learning on chemistry learning and learning perceptions. Sample, design and methods: By adopting the STAD approach, this study examined 144 nursing students at a five-year junior college in northern Taiwan during the first semester (totaling 18 weeks) of the 2008 academic year. Results: The findings reveal that both a heterogeneous group with external pressure (involving competitive STAD) and a friendship group with affective pressure (involving traditional learning) enhance group cohesion and assist students' meaningful learning; the heterogeneous group without extra pressure (involving non-competitive STAD), by contrast, fails because of apathy and lassitude. Moreover, learning effectiveness will obviously predominate until the learning strategy continues for a long period or at least one semester. Conclusions: This study revealed that the learning performance level of the competitive STAD group is significantly different from that of the non-competitive STAD group; and the learning performance level of the traditional group is significantly different from that of the non-competitive STAD group. Both the competitive STAD group and traditional group of medium ability students are significantly different from the non-competitive STAD group. Low-ability students from the competitive STAD group are significantly different from those of the non-competitive STAD, though no significant differences were found in learning perception. However, both a lack of friendship and a lack of ability in using algorithms may affect students' chemistry learning. Furthermore, gender imbalance, educational culture, and group emotions are factors that may influence student learning performance. Further study should focus on the use of grouping, improve responsibility in group discussion, and investigate group interaction

  13. The new research centre of the Brazilian Petroleum Company in Rio de Janeiro, Brazil: The achievements in the thermal performance of air-conditioned buildings in the tropics

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Rafael; Marcondes, Monica Pereira; De Benedetto, Gisele S.; Goncalves, Joana Carla Soares; Duarte, Denise Helena Silva; Ramos, Jose Ovidio [Laboratorio de Conforto Ambiental e Eficiencia Energetica (LABAUT), Departamento de Tecnologia da Arquitetura (AUT), Faculdade de Arquitetura e Urbanismo, Universidade de Sao Paulo (FAUUSP), Sao Paulo, Brasil, Rua do Lago, 876, Cidade Universitaria, 05508-900 Sao Paulo, SP (Brazil)

    2008-07-01

    The study on the thermal performance of the air-conditioned buildings of the new research centre of the Brazilian Petroleum Company, in the tropical climate of Rio de Janeiro, was part of a bigger research and consultancy project involving environmental issues. The architectural design was the subject of a national competition in 2004, encompassing over 100,000 m{sup 2}. According to the design brief, out of the 10 buildings of the new research centre, 7 have to be either completely or partially air-conditioned, due to specific occupation requirements. The challenge for better thermal performance was related to systems' energy efficiency, to the introduction of natural ventilation and to the notion of adaptive comfort, which were verified with the support of thermal dynamic simulations. At the early stages of the assessments, the potential for natural ventilation in the working spaces considering the mixed-mode strategy achieved 30% of occupation hours. However, the development of the design project led to fully air-conditioned working spaces, due to users' references regarding the conventional culture of the office environment. Nevertheless, the overall architectural approach in accordance to the climatic conditions still showed a contribution to the buildings' energy efficiency. (author)

  14. An analysis of factors correlated with the achievement of the goal standard for the science portion of the Connecticut Academic Performance Test

    Science.gov (United States)

    Kmetz, Barbara Fotta

    2001-07-01

    This study sought to identify factors that could be used to predict the success of students on the science portion of the grade ten Connecticut Academic Performance Test (CAPT). While the Connecticut State Department of Education measures student achievement in mathematics, reading and writing in grades 4, 6, and 8, science is assessed only in the grade ten CAPT. Since the CAPT science test does not identify specific areas in need of improvement, it is not possible to determine causes for low test scores. To address this, the study investigated the predictive values of the grade eight Mastery Tests in mathematics and reading, the student ability scores of the Otis-Lennon School Ability Index, and grades in prior science courses. The research sample consisted of five hundred and twenty-five students, member of the graduating classes of 2000 and 2001 in a large suburban high school. Students in the study had participated in the district testing program and their scores for the grade seven Otis-Lennon School Ability Test (OLSAT), the grade eight Connecticut Mastery Tests (CMT) and the grade ten Connecticut Academic Performance Tests (CAPT) were available for analysis. This study investigated correlations between student achievement on the CMT and the science subtest of the CAPT, between OLSAT scores and the CAPT science scores, and between grades in ninth grade science and CAPT science scores. Scores were disaggregated by gender and by course level. Hypotheses 1, 2, 3 and 4 investigated the Pearson Product Moment Correlations of the OLSAT, CMT and course grades with scores on the science portion of the CAPT. Hypothesis 5 compared the scores of male and female students, using the t-test of independent sample means. Calculations showed moderate correlations for hypotheses 1--4, and the hypotheses were accepted. Hypothesis 5 was accepted for one class and rejected for the other. On the whole, female students received higher course grades and lower standardized test

  15. Training-induced changes in physical performance can be achieved without body mass reduction after eight week of strength and injury prevention oriented programme in volleyball female players

    Directory of Open Access Journals (Sweden)

    M Lehnert

    2017-04-01

    Full Text Available The purpose of the study was to analyse the changes in muscle strength, power, and somatic parameters in elite volleyball players after a specific pre-season training programme aimed at improving jumping and strength performance and injury prevention. Twelve junior female volleyball players participated in an 8-week training programme. Anthropometric characteristics, isokinetic peak torque (PT single-joint knee flexion (H and extension (Q at 60º/s and 180º/s, counter movement jump (CMJ, squat jump (SJ, and reactive strength index (RSI were measured before and after intervention. Significant moderate effects were found in flexor concentric PT at 60º/s and at 180 º/s in the dominant leg (DL (18.3±15.1%, likely; 17.8±11.2%, very likely and in extensor concentric PT at 180º/s (7.4%±7.8%, very likely in the DL. In the non-dominant leg (NL significant moderate effects were found in flexor concentric PT at 60º/s and at 180º/s (13.7±11.3%, likely; 13.4±8.0%, very likely and in extensor concentric PT at 180º/s (10.7±11.5%, very likely. Small to moderate changes were observed for H/QCONV in the DL at 60º/s and 180º/s (15.9±14.1%; 9.6±10.4%, both likely and in the NL at 60º/s (moderate change, 9.6±11.8%, likely, and small to moderate decreases were detected for H/QFUNC at 180º/s, in both the DL and NL (-7.0±8.3%, likely; -9.5±10.0%, likely. Training-induced changes in jumping performance were trivial (for RSI to small (for CMJ and SJ. The applied pre-season training programme induced a number of positive changes in physical performance and risk of injury, despite a lack of changes in body mass and composition. CITATION: Lehnert M, Sigmund M, Lipinska P et al. Training-induced changes in physical performance can be achieved without body mass reduction after eight week of strength and injury prevention oriented programme in volleyball female players. Biol Sport. 2017;34(2:205-213.

  16. Factors associated with failure to achieve remission and with relapse after remission in patients with major depressive disorder in the PERFORM study

    Directory of Open Access Journals (Sweden)

    Saragoussi D

    2017-08-01

    Full Text Available Delphine Saragoussi,1 Maëlys Touya,2 Josep Maria Haro,3 Bengt Jönsson,4 Martin Knapp,5 Bastien Botrel,6 Ioana Florea,7 Henrik Loft,8 Benoît Rive9 1Real-World Evidence and Epidemiology, Lundbeck SAS, Issy-les-Moulineaux, France; 2Health Economics and Outcomes Research, Lundbeck, Deerfield, IL, US; 3Research and Teaching Unit, Parc Sanitari Sant Joan de Deu, CIBERSAM, University of Barcelona, Sant Boi de Llobregat, Barcelona, Spain; 4Department of Economics, Stockholm School of Economics, Stockholm, Sweden; 5Department of Health Policy, London School of Economics and Political Science, London, UK; 6Biostatistics, Inferential, Paris, France; 7Clinical Research Paediatrics, H. Lundbeck A/S, Valby, Denmark; 8Biometrics, H. Lundbeck A/S, Valby, Denmark; 9Global Analytics, Lundbeck SAS, Issy-les-Moulineaux, France Background: The Prospective Epidemiological Research on Functioning Outcomes Related to Major Depressive Disorder (PERFORM study has been initiated to better understand the course of a depressive episode and its impact on patient functioning. This analysis aimed to identify sociodemographic and clinical factors associated with failure to achieve remission at month 2 after initiating or switching antidepressant monotherapy and with subsequent relapse at month 6 for patients in remission at month 2. Materials and methods: This was a 2-year observational cohort study in 1,159 outpatients aged 18–65 years with major depressive disorder initiating or undergoing the first switch of antidepressant monotherapy. Factors with P<0.20 in univariate logistic regression analyses were combined in a multiple logistic regression model to which backward variable selection was applied (ie, sequential removal of the least significant variable from the model and recomputation of the model until all remaining variables have P<0.05. Results: Baseline factors significantly associated with lower odds of remission at month 2 were body-mass index ≥30 kg/m2 (OR 0

  17. Achieving New Source Performance Standards (NSPS) Emission Standards Through Integration of Low-NOx Burners with an Optimization Plan for Boiler Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wayne Penrod

    2006-12-31

    The objective of this project was to demonstrate the use of an Integrated Combustion Optimization System to achieve NO{sub X} emission levels in the range of 0.15 to 0.22 lb/MMBtu while simultaneously enabling increased power output. The project plan consisted of the integration of low-NO{sub X} burners and advanced overfire air technology with various process measurement and control devices on the Holcomb Station Unit 1 boiler. The plan included the use of sophisticated neural networks or other artificial intelligence technologies and complex software to optimize several operating parameters, including NO{sub X} emissions, boiler efficiency, and CO emissions. The program was set up in three phases. In Phase I, the boiler was equipped with sensors that can be used to monitor furnace conditions and coal flow to permit improvements in boiler operation. In Phase II, the boiler was equipped with burner modifications designed to reduce NO{sub X} emissions and automated coal flow dampers to permit on-line fuel balancing. In Phase III, the boiler was to be equipped with an overfire air system to permit deep reductions in NO{sub X} emissions. Integration of the overfire air system with the improvements made in Phases I and II would permit optimization of boiler performance, output, and emissions. This report summarizes the overall results from Phases I and II of the project. A significant amount of data was collected from the combustion sensors, coal flow monitoring equipment, and other existing boiler instrumentation to monitor performance of the burner modifications and the coal flow balancing equipment.

  18. A high performance lithium ion capacitor achieved by the integration of a Sn-C anode and a biomass-derived microporous activated carbon cathode

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Zhu, Yuwen; Pi, Xinxin; Wang, Lijie; Liu, Xin; Qin, Yukun

    2017-02-01

    Hybridizing battery and capacitor materials to construct lithium ion capacitors (LICs) has been regarded as a promising avenue to bridge the gap between high-energy lithium ion batteries and high-power supercapacitors. One of the key difficulties in developing advanced LICs is the imbalance in the power capability and charge storage capacity between anode and cathode. Herein, we design a new LIC system by integrating a rationally designed Sn-C anode with a biomass-derived activated carbon cathode. The Sn-C nanocomposite obtained by a facile confined growth strategy possesses multiple structural merits including well-confined Sn nanoparticles, homogeneous distribution and interconnected carbon framework with ultra-high N doping level, synergically enabling the fabricated anode with high Li storage capacity and excellent rate capability. A new type of biomass-derived activated carbon featuring both high surface area and high carbon purity is also prepared to achieve high capacity for cathode. The assembled LIC (Sn-C//PAC) device delivers high energy densities of 195.7 Wh kg‑1 and 84.6 Wh kg‑1 at power densities of 731.25 W kg‑1 and 24375 W kg‑1, respectively. This work offers a new strategy for designing high-performance hybrid system by tailoring the nanostructures of Li insertion anode and ion adsorption cathode.

  19. Achieving Enhanced Dye-Sensitized Solar Cell Performance by TiCl4/Al2O3 Doped TiO2 Nanotube Array Photoelectrodes

    Directory of Open Access Journals (Sweden)

    Jin Soo Lee

    2015-01-01

    Full Text Available For various reasons, low cost, easy fabrication, and so forth, dye-sensitized solar cells (DSSCs have been consistently studied in many laboratories. To improve the DSSCs performance, using an aqueous solution of titanium tetrachloride (TiCl4 treatment is one of many processes. Before the treatment of TiCl4, nanoporous TiO2 nanotubes (TNTs are fabricated through a secondary anodization process. TiCl4 treatment on TNTs film enhanced short-circuit current density (JSC and aluminum oxide (Al2O3 posttreatment enhanced open-circuit voltage (VOC. As a result, Al2O3 posttreatment on TNTs film conversion efficiency of 8.65% is realized, which is 7% higher than TiCl4 treatment on TNTs film. In this work, we investigated that double dip-coating of TiCl4/Al2O3 treatment on TiO2 nanotubes film had an effect on enhancement of JSC and VOC due to improvement of electron transfer, increment of dye adsorption, and reduction of recombination rate of charge. Photoelectrode DSSCs with light-to-electric energy conversion efficiency were achieved under a simulated solar light irradiation of 100 mW·cm2 (AM 1.5.

  20. A high performance lithium ion capacitor achieved by the integration of a Sn-C anode and a biomass-derived microporous activated carbon cathode

    Science.gov (United States)

    Sun, Fei; Gao, Jihui; Zhu, Yuwen; Pi, Xinxin; Wang, Lijie; Liu, Xin; Qin, Yukun

    2017-01-01

    Hybridizing battery and capacitor materials to construct lithium ion capacitors (LICs) has been regarded as a promising avenue to bridge the gap between high-energy lithium ion batteries and high-power supercapacitors. One of the key difficulties in developing advanced LICs is the imbalance in the power capability and charge storage capacity between anode and cathode. Herein, we design a new LIC system by integrating a rationally designed Sn-C anode with a biomass-derived activated carbon cathode. The Sn-C nanocomposite obtained by a facile confined growth strategy possesses multiple structural merits including well-confined Sn nanoparticles, homogeneous distribution and interconnected carbon framework with ultra-high N doping level, synergically enabling the fabricated anode with high Li storage capacity and excellent rate capability. A new type of biomass-derived activated carbon featuring both high surface area and high carbon purity is also prepared to achieve high capacity for cathode. The assembled LIC (Sn-C//PAC) device delivers high energy densities of 195.7 Wh kg−1 and 84.6 Wh kg−1 at power densities of 731.25 W kg−1 and 24375 W kg−1, respectively. This work offers a new strategy for designing high-performance hybrid system by tailoring the nanostructures of Li insertion anode and ion adsorption cathode. PMID:28155853

  1. Three dimensional stagnation point flow of bionanofluid with variable transport properties

    Directory of Open Access Journals (Sweden)

    N.A. Amirsom

    2016-09-01

    Full Text Available Bionanofluid is a nanofluid in which bioconvection occurs. This paper studies the three dimensional steady stagnation point flow of a bionanofluid with variable transport properties. All the transport properties are dependent on the concentration. Zero mass flux and thermal convective boundary conditions are taken into account. The governing equations of the problem are nondimensionalized and transformed into a set of similarity equations using similarity transformation generated by Lie group analysis. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order numerical method (RKF45. The solutions depend on the viscosity parameter, thermal conductive parameter, mass diffusivity parameter, microorganism diffusivity parameter, Schmidt number, bioconvection Schmidt number and Péclet number. These controlling parameters affect the dimensionless velocity, temperature, nanoparticle volume fraction, microorganisms, the skin friction coefficient, the local Nusselt number and the Sherwood number as well as the motile microorganism rate and are displayed graphically. The results were found to be in good agreement with previous related studies.

  2. Rapid trench initiated recrystallization and stagnation in narrow Cu interconnect lines

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Brendan B.; Rizzolo, Michael; Prestowitz, Luke C.; Dunn, Kathleen A., E-mail: kdunn1@sunypoly.edu [Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203 (United States)

    2015-10-26

    Understanding and ultimately controlling the self-annealing of Cu in narrow interconnect lines has remained a top priority in order to continue down-scaling of back-end of the line interconnects. Recently, it was hypothesized that a bottom-up microstructural transformation process in narrow interconnect features competes with the surface-initiated overburden transformation. Here, a set of transmission electron microscopy images which captures the grain coarsening process in 48 nm lines in a time resolved manner is presented, supporting such a process. Grain size measurements taken from these images have demonstrated that the Cu microstructural transformation in 48 nm interconnect lines stagnates after only 1.5 h at room temperature. This stubborn metastable structure remains stagnant, even after aggressive elevated temperature anneals, suggesting that a limited internal energy source such as dislocation content is driving the transformation. As indicated by the extremely low defect density found in 48 nm trenches, a rapid recrystallization process driven by annihilation of defects in the trenches appears to give way to a metastable microstructure in the trenches.

  3. An automatic, stagnation point based algorithm for the delineation of Wellhead Protection Areas

    Science.gov (United States)

    Tosco, Tiziana; Sethi, Rajandrea; di Molfetta, Antonio

    2008-07-01

    Time-related capture areas are usually delineated using the backward particle tracking method, releasing circles of equally spaced particles around each well. In this way, an accurate delineation often requires both a very high number of particles and a manual capture zone encirclement. The aim of this work was to propose an Automatic Protection Area (APA) delineation algorithm, which can be coupled with any model of flow and particle tracking. The computational time is here reduced, thanks to the use of a limited number of nonequally spaced particles. The particle starting positions are determined coupling forward particle tracking from the stagnation point, and backward particle tracking from the pumping well. The pathlines are postprocessed for a completely automatic delineation of closed perimeters of time-related capture zones. The APA algorithm was tested for a two-dimensional geometry, in homogeneous and nonhomogeneous aquifers, steady state flow conditions, single and multiple wells. Results show that the APA algorithm is robust and able to automatically and accurately reconstruct protection areas with a very small number of particles, also in complex scenarios.

  4. Blowup in stagnation-point form solutions of the inviscid 2d Boussinesq equations

    Science.gov (United States)

    Sarria, Alejandro; Wu, Jiahong

    2015-10-01

    The 2d Boussinesq equations model large scale atmospheric and oceanic flows. Whether its solutions develop a singularity in finite-time remains a classical open problem in mathematical fluid dynamics. In this work, blowup from smooth nontrivial initial velocities in stagnation-point form solutions of this system is established. On an infinite strip Ω = { (x, y) ∈ [ 0, 1 ] ×R+ }, we consider velocities of the form u = (f (t, x), - yfx (t, x)), with scalar temperature θ = yρ (t, x). Assuming fx (0, x) attains its global maximum only at points xi* located on the boundary of [ 0, 1 ], general criteria for finite-time blowup of the vorticity - yfxx (t, xi*) and the time integral of fx (t, xi*) are presented. Briefly, for blowup to occur it is sufficient that ρ (0, x) ≥ 0 and f (t, xi*) = ρ (0, xi*) = 0, while - yfxx (0, xi*) ≠ 0. To illustrate how vorticity may suppress blowup, we also construct a family of global exact solutions. A local-existence result and additional regularity criteria in terms of the time integral of ‖fx (t, ṡ) ‖ L∞ ([ 0, 1 ]) are also provided.

  5. The onset of thermal instability of a two-dimensional hydromagnetic stagnation point flow

    Energy Technology Data Exchange (ETDEWEB)

    Amaouche, Mustapha; Bouda, Faical Nait [Laboratoire de physique theorique, Universite de Bejaia, Route de Targua Ouzemour Bejaia (Algeria); Sadat, Hamou [Laboratoire d' Etudes Thermiques, Universite de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers (France)

    2005-10-01

    The aim of the present paper is to examine the effects of a constant magnetic field on the thermal instability of a two-dimensional stagnation point flow. First, it is shown that a basic flow, described by an exact solution of the full Navier-Stokes equations exists under some conditions relating the orientation of the magnetic field in the plane of motion to the obliqueness of free stream. The stability of the basic flow is then investigated in the usual fashion by making use of the normal mode decomposition. The resulting eigenvalue problem is solved numerically by means of a pseudo spectral collocation method based upon Laguerre's functions. The use of this procedure is warranted by the exponential damping of disturbances far from the boundary layer and the appropriate distribution of the roots of Laguerre's polynomials to treat boundary layer problems. It is found through the calculation of neutral stability curves that magnetic field acts to increase the stability of the basic flow. (author)

  6. Self-Generated Magnetic Fields in Stagnation-Phase ICF Implosions

    Science.gov (United States)

    Walsh, Christopher; Chittenden, Jeremy; McGlinchey, Kristopher; Niasse, Nicolas

    2016-10-01

    3-D extended-MHD simulations of the stagnation phase of an ICF implosion are presented, showing significant self-generated magnetic fields (1000-5000T) due to the Biermann Battery effect. Perturbed hot-spots generate magnetic fields at their edges, as the extremities of hot bubbles are rapidly cooled by the surrounding low temperature fuel, giving non-parallel electron pressure and density gradients. Larger amplitude and higher mode-number perturbations lead to an increased hot-spot surface area and more heat flow, developing greater non-parallel gradients and therefore larger magnetic fields. Due to this, largely perturbed hot-spots can be affected more by magnetic fields, although the accelerated cooling associated with greater deviations from symmetry lowers magnetisation. The Nernst effect advects magnetic field down temperature gradients towards the outer region of the hot-spot, which can also lower the magnetisation of the plasma. In some regions, however, the Nernst velocity is convergent, magnetising the tips of cold fuel spikes, resulting in anisotropic heat-flow and an improvement in energy containment. Low-mode and multi-high-mode simulations are shown, with magnetisations reaching sufficiently high levels in some regions of the hot-spot to suppress thermal conduction to lower than 50% of the unmagnetised case. A quantitative analysis of how this affects the hot-spot energy balance is included.

  7. Analytical study of the non orthogonal stagnation point flow of a micro polar fluid

    Directory of Open Access Journals (Sweden)

    M. Ali. Abbas

    2017-01-01

    Full Text Available In this paper we consider the steady two dimensional flow of micro polar fluids on a flat plate. The flow under discussion is the modified Hiemenz flow for a micro polar fluid which occurs in the hjkns + skms boundary layer near an orthogonal stagnation point. The full governing equation reduced to a modified Hiemenz flow. The solution to the boundary value problem is governed by two non dimensional parameters, the material parameter K and the ratio of the micro rotation to skin friction parameter n. The obtained nonlinear coupled ordinary differential equations are solved by using the Homotopy perturbation method. Comparison between numerical and analytical solutions of the problem is shown in tables form for different values of the governing parameters K and n. Effects of the material parameter K on the velocity profile and microrotation profiles for different cases of n are discussed graphically as well as numerically. Velocity profile decreases as the material parameter K increases and the microrotation profile increases as the material parameter K increases for different cases of n.

  8. Radiation Effect on MHD Stagnation-Point Flow of a Nanofluid over an Exponentially Stretching Sheet

    Directory of Open Access Journals (Sweden)

    Imran ANWAR

    2014-07-01

    Full Text Available This paper theoretically investigates the radiation effect on magnetohydrodynamics (MHD stagnation-point flow of a nanofluid over an exponentially stretching sheet under the assumptions of a small magnetic Reynolds number. The sheet is stretched with an exponential velocity in the presence of a non-uniform magnetic field B applied in a transverse direction normal to the flow. By using the modified Bernoulli's equation, a highly nonlinear nanofluid problem is modeled for an electrically conducting nanofluid. The momentum, thermal and concentration boundary layer thicknesses are intensified for the incorporated flow parameters such as Brownian motion parameter Nb, thermophoresis parameter Nt, Prandtl number Pr, Lewis number Le, Hartmann number Mexp and velocity ratio parameter ε. Also by an appropriate similarity transformation, the system of nonlinear partial differential equations is reduced to ordinary differential equations. These equations subjected to the boundary conditions are solved numerically using the Keller-box method. Numerical results are plotted and discussed for pertinent flow parameters. A comparison with existing results in the literature is also provided.doi:10.14456/WJST.2014.11

  9. Two-Dimensional Stagnation-Point Velocity-Slip Flow and Heat Transfer over Porous Stretching Sheet

    Directory of Open Access Journals (Sweden)

    FEROZ AHMED SOOMRO

    2016-10-01

    Full Text Available Present paper investigates 2D (Two-Dimensional stagnation-point velocity-slip flow over porous stretching sheet. The governing non-linear PDEs (Partial Differential Equations are non-dimensionlized by using the similarity transformation technique that results into coupled non-linear ODEs (Ordinary Differential Equations. Such ODEs are then solved by using shooting technique with fourth-order Runge-Kutta method. Since the behavior of boundary layer stagnation-point flow depends on the rate of cooling and stretching. Therefore, the main objective of this paper is to analyze the effects of different working parameters on shear stress, heat transfer, velocity and temperature of fluid. The results revealed that the velocity-slip has significant effect on the fluid flow as well as on the heat transfer. The numerical results are also compared with existing work for no-slip condition and found to have good agreement with improved asymptotic behavior.

  10. Mixed Convection In The Stagnation-Point Flow Over A Vertical Stretching Sheet In The Presence Of Thermal Radiation

    Directory of Open Access Journals (Sweden)

    Manjunatha S.

    2015-12-01

    Full Text Available An unsteady two-dimensional stagnation-point mixed convection flow of a viscous, incompressible dusty fluid towards a vertical stretching sheet has been examined. The stretching velocity and the free stream velocity are assumed to vary linearly with the distance from the stagnation point. The problem is analyzed using similarity solutions. The similarity ordinary differential equations were then solved numerical by using the RKF-45 method. The effects of various physical parameters on the velocity profile and skin-friction coefficient are also discussed in this paper. Some important findings reported in this work reveal that the effect of radiation has a significant impact on controlling the rate of heat transfer in the boundary layer region.

  11. A fine-wire thermocouple probe for measurement of stagnation temperatures in real gas hypersonic flows of nitrogen

    Science.gov (United States)

    Hollis, Brian R.; Griffith, Wayland C.; Yanta, William J.

    1991-01-01

    A fine-wire thermocouple probe was used to determine freestream stagnation temperatures in hypersonic flows. Data were gathered in a N2 blowdown wind tunnel with runtimes of 1-5 s. Tests were made at supply pressures between 30 and 1400 atm and supply temperatures between 700 and 1900 K, with Mach numbers of 14 to 16. An iterative procedure requiring thermocouple data, pilot pressure measurements, and supply conditions was used to determine test cell stagnation temperatures. Probe conduction and radiation losses, as well as real gas behavior of N2, were accounted for during analysis. Temperature measurement error was found to be 5 to 10 percent. A correlation was drawn between thermocouple diameter Reynolds number and temperature recovery ratio. Transient probe behavior was studied and was found to be adequate in temperature gradients up to 1000 K/s.

  12. Vortices induced in a stagnation region by wakes - Their incipient formation and effects on heat transfer from cylinders

    Science.gov (United States)

    Nagib, H. M.; Hodson, P. R.

    1977-01-01

    Horseshoe-like vortices, induced by wakes in the stagnation region of bluff bodies, are proposed as an efficient mechanism for augmentation of convective heat transfer. The vortex 'flow module' induced by single or multiple wakes, which had not been observed previously, was first documented and the resulting flow field was studied using various visualization techniques and hot-wire anemometry. In an attempt to understand the driving force behind this flow module, the conditions at which incipient formation of the vortices occurs were investigated. Existence of such a threshold is essential and was hitherto an open question in analytical studies of stability of flow in stagnation region. Finally, effects of the flow module on heat transfer from a cylinder were measured.

  13. Nonlinear convection stagnation point heat transfer and MHD fluid flow in porous medium towards a permeable shrinking sheet

    CERN Document Server

    Kumar, Rakesh

    2015-01-01

    This investigation deals with the analysis of stagnation point heat transfer and corresponding flow features of hydromagnetic viscous incompressible fluid over a vertical shrinking sheet. The considered sheet is assumed to be permeable and subject to addition of stagnation point to control the generated vorticity in the boundary layer. The sheet is placed on the right side of the fluid saturated porous medium which is having permeability of specified form. Nonlinear convection waves in the flow field are realized due to the envisaged nonlinear relation between density and temperature. The equations governing the nonlinear convection boundary layer flow are modeled and simplified using similarity transformations. The economized equations are solved for numerical solutions by employing the implicit finite difference scheme also known as Keller-box method. The influence of the associated parameters of the problem on velocity and temperature distributions, skin friction and rate of heat transfer are presented thr...

  14. A uniformly valid series solution to the unsteady stagnation-point flow towards an impulsively stretching surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The paper studies the problem of the unsteady two-dimensional stagnation-point flow of an incompressible viscous fluid over a flat deformable sheet. The flow is started impulsively from rest and the sheet is suddenly stretched in its own plane with a velocity proportional to the distance from the stagnation point. An analytical series solution is obtained by means of the homotopy analysis method (HAM). Also, the homotopy-Pade′ technique is employed. An explicit formula for the local friction coefficient is provided. The present formula, different from the perturbation solution, is accurate and uniformly valid for all dimensionless time in the whole spatial region and for all possible values of physical parameter λ, defined as the ratio of the potential flow velocity to the sheet sudden stretching velocity. Numerical tests are done to verify the present formula for its validity and accuracy.

  15. Dynamical trapping of colloids at the stagnation points of electro-osmotic vortices of the second kind

    Science.gov (United States)

    Green, Yoav; Yossifon, Gilad

    2013-03-01

    By applying a stepwise overlimiting voltage to a nanoslot system in equilibrium, it is possible to follow the time evolution of the electroconvective instability vortex array via the depletion dynamics or, alternatively, by following dielectrophoretically trapped particles at the stagnation points of each of the hydrodynamic vortex pairs. Particles are advected to the stagnation point by the hydrodynamics, where they are trapped by a short-range dielectrophoretic force. It is experimentally confirmed that the wavelength selection process occurs at the diffusive time scale and that the wavelength selection mechanism, started by the Rubinstein and Zaltzman electroconvective instability is eventually determined by the system lateral geometry and dictated by Dukhin's electro-osmosis of the second kind. The steady-state case was numerically studied by solving the fully coupled electroconvective problem, confirming that the vortex stagnation point is indeed of a converging type. The particle's planar (two-dimensional) equations of motion are solved after adding a dielectrophoretic force that accounts for quasi-three-dimensional effects. It is shown that this force can account for trapping at the nanoslot interface.

  16. Clinical Study of Clearing Heat and Relieving Stagnation Massage Therapy on Children Stagnation of Milk and Food%清热导滞推拿法治疗小儿积滞乳食内积证临床研究

    Institute of Scientific and Technical Information of China (English)

    陈秀珍; 殷明

    2012-01-01

    Objective: To observe the massage therapy of clearing heat stagnation for treatment of infantile accumulation stagnation of milk and food. Method: 80 cases of infantile accumulation stagnation of milk and food were divided into massage therapy group and oral Wangshi Baochi Pill control group, 40 patients of two groups. After 2 courses, children appetite, abdominal distension and the improvement of the symptoms were analyzed. Results : Appetite, abdominal distension and mental condition of the two groups have improved in different degrees, and the cure rate of treatment group was better than that in control group, statistically, the difference had statistical significance ( P<0.05 ), the effect of the treatment group was superior to that of the control group. Conclusion: Heat-clearing and stagnation-clearing massage therapy on children stagnation of milk and food has a significant clinical effect, the younger, the better.%目的:观察清热导滞推拿法治疗小儿积滞乳食内积证的有效性.方法:选取80例小儿积滞乳食内积证患儿分成推拿治疗组和口服王氏保赤丸对照组,两组各40例,2疗程后统计患儿食欲食量、腹胀及伴随症状改善情况.结果:两组食欲食量、腹胀及精神状况有不同程度的改善,治疗组痊愈率及总有效率明显高于对照组,经统计学处理,两者差异有统计意义(P<0.05),治疗组疗效优于对照组.结论:清热导滞推拿法治疗小儿积滞乳食内积证临床疗效显著,且年龄越小效果越好.

  17. Biological basis of “depression with liver-qi stagnation and spleen deficiency syndrome”: A digital gene expression profiling study

    Directory of Open Access Journals (Sweden)

    Junling Li

    2015-07-01

    Conclusions: Hnf4α, Hnf4γ and Cyp1a1 are involved in “depression with liver-qi stagnation and spleen deficiency syndrome”. These findings indicate that depressed rats with liver-qi stagnation and spleen deficiency syndrome are at risk of liver diseases. Furthermore, our results will inform exploration of the etiology of depression and help in the development of effective therapeutic strategies.

  18. Achieving high gene delivery performance with caveolae-mediated endocytosis pathway by (l)-arginine/(l)-histidine co-modified cationic gene carriers.

    Science.gov (United States)

    Li, Hui; Luo, Ting; Sheng, Ruilong; Sun, Jingjing; Wang, Zhao; Cao, Amin

    2016-12-01

    Developing new amphiphilic polymers with natural product moieties has been regarded as a promising way to achieve biocompatibility and certain biological functions. In prior work, we developed some natural (l)-arginine modified cationic polymers (PAHMAA-Rs) as cationic gene carriers. For the sake of continuing optimize the gene delivery performance, herein, a new series of (l)-arginine and (l)-histidine co-modified cationic poly (ω-aminohexyl methacrylamide)s (PAHMAA-R-H) were synthesized and characterized with (1)H NMR, GPC-SLS and FT-IR. Their proton buffering capacities were studied by acid-base titration assay. pDNA binding affinity and self-assembly properties of the polyplexes were analyzed by agarose gel retardation assay, DLS and AFM, respectively. In vitro cytotoxicity of the PAHMAA-R-H was determined by MTT and LDH assays in H1299 cells, the gene transfection efficacy and intracellular uptake capability were evaluated by luciferase assay and FACS, respectively. Moreover, the endocytosis pathways and intracellular distribution of the polyplexes were investigated by using specific endocytic inhibitors and fluorescent co-localization techniques. The results demonstrated that co-modification of (l)-arginine and (l)-histidine onto the PAHMAA polymer could enhance proton buffering capacity, shield surface charge, decrease cytotoxicity, and improve gene transfection efficiency and serum-compatibility. Moreover, the gene transfection and intracellular uptake behaviors were disclosed strongly rely on the (l)-arginine/(l)-histidine modification ratios. The polyplexes tend to be internalized through caveolae-mediated endocytosis gateway and localized with endosomes/lysosomes in H1299 cells. Notably, among the polymers, the PAHMAA-R18-H6 exhibited remarkable gene delivery efficiency and serum compatibility, which made it promising gene transfection agent for practical application.

  19. 论创新停滞的界定及规避——以日本电子工业企业为例%Analysis of Defining and Avoiding Innovation Stagnation ----Based on Predicament of Japanese Electronics Companies

    Institute of Scientific and Technical Information of China (English)

    刘文

    2012-01-01

    The performance of Japanese electronics companies has declined dramatically in recent years and their operation run into difficulties. The major cause lies in innovation stagnation, that is,compa- nies have not invested in new technology and R&D activities for a long time with disruptive innovation coming to the end. Although American companies also have innovation stagnation,America has the en- vironment that can push"disruptive wheel" for companies while Japanese companies do not have. Chi- na's companies also come up against innovation stagnation,they should be aware of the significance of incessant disruptive innovation. On the other hand , China's government should create favourable envi- ronment for"disruptive wheel"in order to help companies to avoid the predicament caused by innova- tion stagnation.%日本电子工业企业近些年业绩大幅下滑,经营陷入困境。造成这一局面的主要原因是创新停滞,即企业在相当长一段时期内没有新技术的投入和研发,破坏性创新不再持续。美国企业虽然有创新停滞现象,但美国有能够推动"破坏之轮"的环境,从而使一些企业持续进行破坏性创新,而日本企业缺乏这种环境。创新停滞问题也在我国企业中出现,因此我国企业应当认识到持续不断地进行破坏性创新的重要意义,政府也应当积极培育有利于"破坏之轮"发展的环境,帮助企业避免创新停滞导致的困境。

  20. To compare the efficacy of two kinds of Zhizhu pills in the treatment of functional dyspepsia of spleen-deficiency and qi-stagnation syndrome:a randomized group sequential comparative trial

    Directory of Open Access Journals (Sweden)

    Huang Luqi

    2011-07-01

    Full Text Available Abstract Background In Traditional Chinese Medicine (TCM theory, functional dyspepsia (FD can be divided into different syndromes according to different clinical symptoms and signs, and the most common one is spleen-deficiency and qi-stagnation syndrome that can be treated by Chinese traditional patent medicine ---- two kinds of Zhizhu pills, between which the primary difference in ingredients is that one contains immature orange fruit of Citrus aurantium L.(IFCA and the other contains that of Citrus sinensis Osbeck (IFCS. The trial's objective was to compare the efficacy of two kinds of Zhizhu pills on symptom changes in patients with FD of spleen-deficiency and qi-stagnation syndrome. Methods A randomized, group sequential, double-blinded, multicenter trial was conducted in patients with FD of spleen-deficiency and qi-stagnation syndrome at 3 hospitals in Beijing between June 2003 and May 2005. Participants were randomly allocated into two groups (IFCA group and IFCS group in a 1:1 ratio, and respectively took one of the two kinds of Zhizhu pills orally, 6 g each time, 3 times a day, for 4 weeks. Statistical analysis was performed with use of a group sequential method, the triangular test (TT. Results A total of 163 patients were randomized, and 3 patients were excluded from analysis because of early dropouts, leaving 160 patients (IFCA group: n = 82; IFCS group: n = 78 for statistical analysis. Three interim analyses were done after 62, 116, and 160 patients had completed their 4-week treatment, respectively. At the third interim analysis, the sample path crossed the upper boundary and the trial was stopped, the cure-markedly effective rates were 45% for IFCS group and 67% for IFCA group, respectively, the one-sided p-value was 0.0036, the median unbiased estimate of the odds ratio (OR for the benefit of IFCA relative to IFCS was 2.91 with 95%CI: 1.40 to 6.06. No adverse events were observed in the two groups. Conclusions Zhizhu pills

  1. Large amplitude oscillation of a boiling bubble growing at a wall in stagnation flow

    Energy Technology Data Exchange (ETDEWEB)

    Geld, C.W.M. van der; Berg, R. van de; Peukert, P. [Eindhoven University of Technology, Eindhoven (Netherlands). Faculty of Mechanical Engineering], e-mail: C.W.M._v.d.Geld@tue.nl

    2009-07-01

    A boiling bubble is created on an artificial site that is part of a bubble generator that is mounted at the center of a pipe. Downflow of water impinges on the bubble generator and creates a stagnation flow above the artificial cavity. Stable axisymmetric elongation in the direction away from the wall and multiple shape oscillation cycles are observed. The time of growth and attachment is typically of the order of 250 ms. Amongst the length scales that characterize the bubble shape is the radius of curvature of the upper part of the bubble, R. The period of oscillation, T, is strongly dependent on time, as is R. The parameters C and m in the defining equation T = C R{sup m} {radical}({rho}L/{sigma}) have been determined by fitting to data of more than 100 bubbles. For each operating condition, the same values of C and m have been found. The value of m is 1.49 {+-} 0.02, which is explained from the continuous growth of the bubble and from the relation to the period of oscillation of a free bubble deforming in the fundamental mode corresponding to the third Legendre Polynomial. For the latter, R is the radius of the volume-equivalent sphere, R{sub 0}, and C is {radical}12, while for attached boiling bubbles C is found to amount 1.9{radical}12. The difference is easily explained from the continuous growth, difference in definition, finite amplitude oscillation and proximity of the wall. (author)

  2. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome.

    Directory of Open Access Journals (Sweden)

    Pan Ji

    Full Text Available A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing. To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9-10 had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome.

  3. Observation and Simulation of Ion Flow Stagnation in the Enceladus Plume

    Science.gov (United States)

    Tokar, R. L.; Omidi, N.; Averkamp, T.; Wang, Z.; Gurnett, D. A.; Thomsen, M. F.; Crary, F. J.

    2010-12-01

    The Cassini Plasma Spectrometer (CAPS) detected freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier charged water clusters (HxO2)+ very close to Enceladus within and outside of the south polar plume, see (1). The data were obtained during close flybys of Enceladus in 2008 and 2009 (E3, E5, E7) when CAPS viewing of the ion plasma was favorable. The ions are observed in CAPS detectors looking in the Cassini ram direction and close to the ram kinetic energy, indicative of a nearly stagnant (at rest with respect to Enceladus) plasma flow in the plume. In this study these CAPS observations are compared with 3D hybrid simulations of the Enceladus interaction (2). The primary goal is to simulate the spatial extent of the ion flow stagnation in and near the plume observed by CAPS. The simulations include not only plume water vapor undergoing charge exchange with the ambient ion flow but also heavy plume dust that acquires a negative charge. The neutral dust spatial distribution is modeled using particle impact rates obtained from Radio and Plasma Wave System (RPWS) data while plasma fluid parameters during the encounters are obtained from CAPS. The dust is a second heavy particle component in the simulation that is followed in the same manner as the positive ions. The dust absorption of electrons mass-loads the plasma producing flow deceleration observable by CAPS over the high impact regions measured by RPWS. This deceleration is compared with that due to the charge exchange process. 1.)Tokar,R.L. et al. Geophys. Res. Lett., 36, L13203, doi:10.1029/2009GL038923, 2009. 2.)Omidi,N. et al., J. Geophys. Res., 115, A05212, doi:10.1029/2009JA014391, 2010.

  4. Are Physical Activity and Academic Performance Compatible? Academic Achievement, Conduct, Physical Activity and Self-Esteem of Hong Kong Chinese Primary School Children

    Science.gov (United States)

    Yu, C. C. W.; Chan, Scarlet; Cheng, Frances; Sung, R. Y. T.; Hau, Kit-Tai

    2006-01-01

    Education is so strongly emphasized in the Chinese culture that academic success is widely regarded as the only indicator of success, while too much physical activity is often discouraged because it drains energy and affects academic concentration. This study investigated the relations among academic achievement, self-esteem, school conduct and…

  5. Feelings and Performance in the First Year at University: Learning-Related Emotions as Predictors of Achievement Outcomes in Mathematics and Statistics

    Science.gov (United States)

    Niculescu, Alexandra C.; Templelaar, Dirk; Leppink, Jimmie; Dailey-Hebert, Amber; Segers, Mien; Gijselaers, Wim

    2015-01-01

    Introduction: This study examined the predictive value of four learning-related emotions--Enjoyment, Anxiety, Boredom and Hopelessness for achievement outcomes in the first year of study at university. Method: We used a large sample (N = 2337) of first year university students enrolled over three consecutive academic years in a mathematics and…

  6. Autonomy Support and Achievement Goals as Predictors of Perceived School Performance and Life Satisfaction in the Transition between Lower and Upper Secondary School

    Science.gov (United States)

    Diseth, Åge; Samdal, Oddrun

    2014-01-01

    A self-determination theory perspective on motivation assumes that basic need support is a prerequisite for motivation, achievement, and well-being in several domains of life. In the present cross-sectional study, a representative sample of 2.594 Norwegian students in their final year of lower secondary education and their first year of upper…

  7. Unsteady Stagnation Point Flow and Heat Transfer over a Stretching/Shrinking Sheet with Suction or Injection

    Directory of Open Access Journals (Sweden)

    M. Suali

    2012-01-01

    Full Text Available The unsteady stagnation point flow and heat transfer over a stretching/shrinking sheet with suction/injection is studied. The governing partial differential equations are converted into nonlinear ordinary differential equations using a similarity transformation and solved numerically. Both stretching and shrinking cases are considered. Results for the skin friction coefficient, local Nusselt number, velocity, and temperature profiles are presented for different values of the governing parameters. It is found that the dual solutions exist for the shrinking case, whereas the solution is unique for the stretching case. Numerical results show that the range of dual solutions increases with mass suction and decreases with mass injection.

  8. Unsteady stagnation point flow and heat transfer over a stretching/shrinking sheet with prescribed surface heat flux

    Directory of Open Access Journals (Sweden)

    A. Ishak

    2012-08-01

    Full Text Available An analysis is carried out to study the unsteady two dimensional stagnation point flow and heat transfer over a stretching/shrinking sheet with prescribed surface heat flux. The governing partial differential equations are converted into nonlinear ordinary differential equations using similarity variables, and solved numerically. The effects of the unsteadiness parameter A, stretching/shrinking parameter ε and Prandtl number Pr on the flow and heat transfer characteristics are studied. It is found that the skin friction f′′(0 and the local Nusselt number 1θ(0 increase as the the unsteadiness parameter A increases. Moreover, the velocity and temperature increase as ε and Pr increase.

  9. Radiation effects on MHD stagnation point flow of nano fluid towards a stretching surface with convective boundary condition

    Institute of Scientific and Technical Information of China (English)

    Noreen Sher Akbar; S. Nadeem; Rizwan Ul Haq; Z.H. Khan

    2013-01-01

    The aim of the present paper is to study the numerical solutions of the steady MHD two dimensional stagnation point flow of an incompressible nano fluid towards a stretching cylinder. The effects of radiation and convective boundary condition are also taken into account. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The result-ing nonlinear momentum, energy and nano particle equations are simplified using similarity trans-formations. Numerical solutions have been obtained for the velocity, temperature and nanoparticle fraction profiles. The influence of physical parameters on the velocity, temperature, nanoparticle fraction, rates of heat transfer and nanoparticle fraction are shown graphically.

  10. Magnetic Field and Slip Effects on the Flow and Heat Transfer of Stagnation Point Jeffrey Fluid over Deformable Surfaces

    Science.gov (United States)

    Turkyilmazoglu, Mustafa

    2016-06-01

    The Mhd slip flow and heat transfer of stagnation point Jeffrey fluid over deformable surfaces are the state of the art of this article. Following an analytical approach, the existence, uniqueness, and possible multiplicity of the physical solutions affected by several physical parameters are investigated. Particularly, magnetic interaction and slip factor are shown to much influence the structure of the solutions regarding both momentum and thermal boundary layers. The presented exact solutions not only provide a clear understanding of fruitful physical mechanisms present in this nonlinear flow problem but they have also merits in calculations by means of numerous numerical schemes aiming to explore further complex phenomena.

  11. The Relationship between Stasis-Stagnation Constitution and Peripheral Arterial Disease in Patients with Type 2 Diabetes

    OpenAIRE

    Kuo-Chin Huang; Ching-Chu Chen; Yi-Chang Su; Jui-Shan Lin; Chwen-Tzuei Chang; Tzu-Yuan Wang; Rong-Hsing Chen; Fuu-Jen Tsai

    2014-01-01

    Objectives. In traditional Chinese medicine, Yu-Zhi (YZ, indicating stasis and stagnation) constitution describes a body that tends to express abnormal circulatory conditions. This study identified the linkage between YZ constitution and peripheral arterial disease (PAD) in patients with type 2 diabetes. Methods. Patients over 20 years of age who had had type 2 diabetes for 5 years or longer were recruited. PAD was diagnosed if the ankle-brachial index score was ≤0.9 in either leg. Level of Y...

  12. Unsteady stagnation-point flow and heat transfer of a special third grade fluid past a permeable stretching/shrinking sheet

    Science.gov (United States)

    Naganthran, Kohilavani; Nazar, Roslinda; Pop, Ioan

    2016-04-01

    In this paper, the unsteady stagnation-point boundary layer flow and heat transfer of a special third grade fluid past a permeable stretching/shrinking sheet has been studied. Similarity transformation is used to transform the system of boundary layer equations which is in the form of partial differential equations into a system of ordinary differential equations. The system of similarity equations is then reduced to a system of first order differential equations and has been solved numerically by using the bvp4c function in Matlab. The numerical solutions for the skin friction coefficient and heat transfer coefficient as well as the velocity and temperature profiles are presented in the forms of tables and graphs. Dual solutions exist for both cases of stretching and shrinking sheet. Stability analysis is performed to determine which solution is stable and valid physically. Results from the stability analysis depict that the first solution (upper branch) is stable and physically realizable, while the second solution (lower branch) is unstable.

  13. An experimental study on the influence of water stagnation and temperature change on water quality in a full-scale domestic drinking water system.

    Science.gov (United States)

    Zlatanović, Lj; van der Hoek, J P; Vreeburg, J H G

    2017-10-15

    The drinking water quality changes during the transport through distribution systems. Domestic drinking water systems (DDWSs), which include the plumbing between the water meter and consumer's taps, are the most critical points in which water quality may be affected. In distribution networks, the drinking water temperature and water residence time are regarded as indicators of the drinking water quality. This paper describes an experimental research on the influence of stagnation time and temperature change on drinking water quality in a full-scale DDWS. Two sets of stagnation experiments, during winter and summer months, with various stagnation intervals (up to 168 h of stagnation) were carried out. Water and biofilms were sampled at two different taps, a kitchen and a shower tap. Results from this study indicate that temperature and water stagnation affect both chemical and microbial quality in DDWSs, whereas microbial parameters in stagnant water appear to be driven by the temperature of fresh water. Biofilm formed in the shower pipe contained more total and intact cells than the kitchen pipe biofilm. Alphaproteobacteria were found to dominate in the shower biofilm (78% of all Proteobacteria), while in the kitchen tap biofilm Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria were evenly distributed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Which Feedback Is More Effective for Pursuing Multiple Goals of Differing Importance? The Interaction Effects of Goal Importance and Performance Feedback Type on Self-Regulation and Task Achievement

    Science.gov (United States)

    Lee, Hyunjoo

    2016-01-01

    This study examined how performance feedback type (progress vs. distance) affects Korean college students' self-regulation and task achievement according to relative goal importance in the pursuit of multiple goals. For this study, 146 students participated in a computerised task. The results showed the interaction effects of goal importance and…

  15. Comparison of volatility distributions in the periods of booms and stagnations: an empirical study on stock price indices

    CERN Document Server

    Kaizoji, T

    2005-01-01

    The aim of this paper is to compare statistical properties of stock price indices in periods of booms with those in periods of stagnations. We use the daily data of the four stock price indices in the major stock markets in the world: (i) the Nikkei 225 index (Nikkei 225) from January 4, 1975 to August 18, 2004, of (ii) the Dow Jones Industrial Average (DJIA) from January 2, 1946 to August 18, 2004, of (iii) Standard and Poor's 500 index (SP500) from November 22, 1982 to August 18, 2004, and of (iii) the Financial Times Stock Exchange 100 index (FT 100) from April 2, 1984 to August 18, 2004. We divide the time series of each of these indices in the two periods: booms and stagnations, and investigate the statistical properties of absolute log returns, which is a typical measure of volatility, for each period. We find that (i) the tail of the distribution of the absolute log-returns is approximated by a power-law function with the exponent close to 3 in the periods of booms while the distribution is described b...

  16. Standard Practice for Exposure of Solar Collector Cover Materials to Natural Weathering Under Conditions Simulating Stagnation Mode

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1992-01-01

    1.1 This practice covers a procedure for the exposure of solar collector cover materials to the natural weather environment at elevated temperatures that approximate stagnation conditions in solar collectors having a combined back and edge loss coefficient of less than 1.5 W/(m2 · °C). 1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials. 1.3 This practice does not apply to cover materials for evacuated collectors, photovoltaic cells, flat-plate collectors having a combined back and edge loss coefficient greater than 1.5 W/(m2 ·° C), or flat-plate collectors whose design incorporates means for limiting temperatures during stagnation. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard t...

  17. Unaxisymmetric stagnation-point flow and heat transfer of a viscous fluid with variable viscosity on a cylinder

    Directory of Open Access Journals (Sweden)

    Rasool Alizadeh

    2016-06-01

    Full Text Available Existing solutions of the problem of axisymmetric stagnation-point flow and heat transfer on either a cylinder or a flat plate are for incompressible fluid. Here, fluid with viscosity proportional to a linear function of temperature is considered in the problem of an unaxisymmetric stagnation-point flow and heat transfer of an infinite stationary cylinder with non-uniform normal transpiration U0(φ and constant heat flux. The impinging free-stream is steady and with a constant strain rate k¯. A reduction of Navier–Stokes and energy equations is obtained by use of appropriate similarity transformations. The semi-similar solution of the Navier–Stokes equations and energy equation has been obtained numerically using an implicit finite-difference scheme. All the solutions aforesaid are presented for Reynolds numbers, Re=k¯a2/2υ∞, ranging from 0.01 to 100 for different values of Prandtl number and viscosity-variation parameter and for selected values of transpiration rate function, S(φ=U0(φ/k¯a, where a is cylinder radius and υ∞ is the reference kinematic viscosity of the fluid. Dimensionless shear-stresses corresponding to all the cases increase with the increase in Reynolds number and transpiration rate function while dimensionless shear stresses decrease with the increase in viscosity-variation parameter. The local coefficient of heat transfer (Nusselt number increases with increasing the transpiration rate function and Prandtl number.

  18. The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

    KAUST Repository

    Alshaarawi, Amjad

    2015-03-01

    A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

  19. Achieving ICME with Multiscale Modeling: The Effects of Constituent Properties and Processing on the Performance of Laminated Polymer Matrix Composite Structures

    Science.gov (United States)

    Pineda, Evan Jorge; Bednarcyk, Brett A.; Arnold, Steven M.

    2014-01-01

    Integrated computational materials engineering (ICME) is a useful approach for tailoring the performance of a material. For fiber-reinforced composites, not only do the properties of the constituents of the composite affect the performance, but so does the architecture (or microstructure) of the constituents. The generalized method of cells is demonstrated to be a viable micromechanics tool for determining the effects of the microstructure on the performance of laminates. The micromechanics is used to predict the inputs for a macroscale model for a variety of different fiber volume fractions, and fiber architectures. Using this technique, the material performance can be tailored for specific applications by judicious selection of constituents, volume fraction, and architectural arrangement given a particular manufacturing scenario

  20. Measurement of Perceived Parental Success Standards in Sport and Relations with Athletes’ Self-Esteem, Performance Anxiety, and Achievement Goal Orientation: Comparing Parental and Coach Influences

    Directory of Open Access Journals (Sweden)

    Frank J. Schwebel

    2016-01-01

    Full Text Available The Perceived Parent Success Standards Scale (PPSSS, adapted from the Perception of Success Questionnaire constructed by Roberts et al. (1998 to measure athletes’ achievement goal orientation, provides a measure of athletes’ perceptions of mastery- and ego-oriented parental success criteria, a central component of parental motivational climate. This study focused on 543 young athletes (ages 9–16 on 82 teams in recreational basketball leagues. The PPSSS exhibited strong factorial validity, construct validity, and orthogonality between ego and mastery factors that allow for different combinations of these factors to be tested. We also compared the impact of the motivational climates created by coaches and success standards conveyed by parents on postseason athlete outcome measures of anxiety, self-esteem, and achievement goal orientation. Correlational and multilevel regression analyses revealed that both coach and parent variables were significantly related to the athlete variables. However, mediational analyses indicated that parental success standards mediated relations between coach-initiated climate and all of the outcome variables, reflecting the power of parental socialization processes. We discuss potential reasons for the greater parental influence shown in this and a previous study, and we suggest directions for further research as well as possible interventions that can help both coaches and parents create a more positive athletic environment for young athletes.

  1. Closing the social-class achievement gap: a difference-education intervention improves first-generation students' academic performance and all students' college transition.

    Science.gov (United States)

    Stephens, Nicole M; Hamedani, MarYam G; Destin, Mesmin

    2014-04-01

    College students who do not have parents with 4-year degrees (first-generation students) earn lower grades and encounter more obstacles to success than do students who have at least one parent with a 4-year degree (continuing-generation students). In the study reported here, we tested a novel intervention designed to reduce this social-class achievement gap with a randomized controlled trial (N = 168). Using senior college students' real-life stories, we conducted a difference-education intervention with incoming students about how their diverse backgrounds can shape what they experience in college. Compared with a standard intervention that provided similar stories of college adjustment without highlighting students' different backgrounds, the difference-education intervention eliminated the social-class achievement gap by increasing first-generation students' tendency to seek out college resources (e.g., meeting with professors) and, in turn, improving their end-of-year grade point averages. The difference-education intervention also improved the college transition for all students on numerous psychosocial outcomes (e.g., mental health and engagement).

  2. Achieving high performance non-fullerene organic solar cells through tuning the numbers of electron deficient building blocks of molecular acceptors

    Science.gov (United States)

    Yang, Lei; Chen, Yusheng; Chen, Shangshang; Dong, Tao; Deng, Wei; Lv, Lei; Yang, Saina; Yan, He; Huang, Hui

    2016-08-01

    Two analogous dimer and tetramer compounds, SF-PDI2 and SF-PDI4, were designed, theoretically calculated, synthesized, and developed as electron acceptors for organic solar cells. The effects of the number of the electron deficient building blocks on the optical absorption, energy levels, charge transport, morphology, crystallinity, and photovoltaic performance of the molecules were investigated. In combination with two different donors, PTB7-Th and PffBT4T-2OD, the results showed that increasing the numbers of PDI building blocks is beneficial to photovoltaic performance and leads to efficiency over 5%.

  3. The effect of parental education, prior achievement, self-efficacy, goal orientation, and effort on undergraduate science performance of Latinos and Caucasians

    Science.gov (United States)

    Stansbury, Sydney Lynn

    Compared with majority students, underrepresented minorities have demonstrated weaker undergraduate science performance. Previous research has attributed the weaker performance to socioeconomic factors that influence poorer precollege preparation. Studies also have found that, compared with majority students, underrepresented minorities are less confident about their science skills and more interested in extrinsic rewards of science careers. Social Cognitive Theory posits that low self-efficacy coupled with high extrinsic goal orientation diminishes cognitive engagement, resulting in weak performance. Applying motivational characteristics of underrepresented minority students to a Social Cognitive Model may explain why their performance is weaker than that of Caucasians. Thus, the purpose of this study was to investigate the degree to which motivation variables account for the difference between underrepresented minority and majority students' undergraduate science performance. The study was conducted at a large, predominantly Caucasian, private university located in an urban setting in the Southwest. Two hundred twenty-two students--154 Caucasians and 68 Latinos--enrolled in a general chemistry course participated. Students were administered the Motivation for Learning Questionnaire, designed specifically for this study, consisting of scales measuring the following variables: ethnicity, level of parental education, and effort exertion; self-efficacy, effort regulation, intrinsic goal orientation, and extrinsic goal orientation, measures from the Motivated Strategies for Learning Questionnaire (Pintrich, Smith, Garcia, & McKeachie, 1991); and ability orientation, a measure from the Patterns of Adaptive Learning Survey (Midgley, Maehr, & Urdan, 1995). Financial aid information, chemistry and math placement test scores, and chemistry grades were obtained from other on-campus departments. Results demonstrated that the hypotheses were only partially confirmed by the

  4. The Effect of Evaluation on Performance: Evidence from Longitudinal Student Achievement Data of Mid-Career Teachers. NBER Working Paper No. 16877

    Science.gov (United States)

    Taylor, Eric S.; Tyler, John H.

    2011-01-01

    The effect of evaluation on employee performance is traditionally studied in the context of the principal-agent problem. Evaluation can, however, also be characterized as an investment in the evaluated employee's human capital. We study a sample of mid-career public school teachers where we can consider these two types of evaluation effect…

  5. Why Do Children Worry about Their Academic Achievement? An Expectancy-Value Perspective on Elementary Students' Worries about Their Mathematics and Reading Performance

    Science.gov (United States)

    Lauermann, Fani; Eccles, Jacquelynne S.; Pekrun, Reinhard

    2017-01-01

    Children's worrying about their academic performance has profound implications for their learning and wellbeing in school. Understanding the contextual and psychological antecedents of students' worry thus represents an important area of research. Drawing on Eccles and colleagues' expectancy-value theory and Pekrun's control-value theory and using…

  6. Are Academic Discounting and Devaluing Double-Edged Swords? Their Relations to Global Self-Esteem, Achievement Goals, and Performance among Stigmatized Students

    Science.gov (United States)

    Loose, Florence; Regner, Isabelle; Morin, Alexandre J. S.; Dumas, Florence

    2012-01-01

    Often taken for granted, the coexistence of benefits and costs of discounting and devaluing has never been tested. Yet, not only are there inconsistent findings about the relations between these processes and global self-esteem, but little is known about their relations to motivation and performance. Here we simultaneously examined how academic…

  7. The Effect of Personnel Stability on Organizational Performance: Do Battalions with Stable Command Groups Achieve Higher Training Proficiency at the National Training Center?

    Science.gov (United States)

    2008-01-01

    As chief, one of Meyer’s first edicts was to declare that the length of command tours would rise from an average of two years to a minimum of...B. Tiggle, and Lynn M. Milan , “The Effects of Battalion Staff Stabilization on Individual and Unit Performance: A Preliminary Investigation”, ARI

  8. The Validity of Pre-Calculus Multiple Choice and Performance-Based Testing as a Predictor of Undergraduate Mathematics and Chemistry Achievement.

    Science.gov (United States)

    Fisher, Gwen Laura

    There has been concern over the validity of the Algebra Diagnostic Test (ADT) used to determine the actual level of student preparation for the first quarter of calculus as taught at the University of California, Santa Barbara. It has been hypothesized that performance-based questions, along with the more traditional multiple choice questions,…

  9. Nasogastric tube-administered alectinib achieved long-term survival in a crizotinib-refractory nonsmall cell lung cancer patient with a poor performance status.

    Science.gov (United States)

    Kanai, Osamu; Kim, Young Hak; Nakatani, Koichi; Fujita, Kohei; Mio, Tadashi

    2017-06-01

    Alectinib shows remarkable efficacy against anaplastic lymphoma kinase (ALK)-positive nonsmall cell lung cancer (NSCLC), with minimal adverse effects. Therefore, alectinib may provide a survival benefit to ALK-positive NSCLC patients with a poor performance status. If the medication cannot be taken by mouth, the patient may be given alectinib through a nasogastric tube.

  10. Does Ontario Have an Achievement Gap? The Challenge of Comparing the Performance of Students in French- and English-Language Schools on National and International Assessments

    Science.gov (United States)

    Childs, Ruth; Denomme, Francine

    2008-01-01

    On national and international assessments, students attending French-language schools in Ontario usually perform worse than students attending English-language schools. Interpreting these results is challenging because the French- and English-language schools differ both in prescribed curriculum and in how the curriculum is taught. In addition,…

  11. The Turnaround Challenge: Why America's Best Opportunity to Dramatically Improve Student Achievement Lies in Our Worst-Performing Schools. Executive Summary

    Science.gov (United States)

    Calkins, Andrew; Guenther, William; Belfiore, Grace; Lash, Dave

    2007-01-01

    Despite steadily increasing urgency about the nation's lowest-performing schools--those in the bottom five percent--efforts to turn these schools around have largely failed. Marginal change has led to marginal (or no) improvement. These schools, the systems supporting them, and the management of the change process require fundamental rethinking,…

  12. Mid-mantle heterogeneities and iron spin transition in the lower mantle: Implications for mid-mantle slab stagnation

    Science.gov (United States)

    Shahnas, M. H.; Yuen, D. A.; Pysklywec, R. N.

    2017-01-01

    Recent high pressure experimental results reveal that the elastic and transport properties of mantle materials are impacted by the electronic spin transition in iron under lower mantle pressure and temperature conditions. The electronic transition in ferropericlase (Fp), the second major constituent mineral of the lower mantle material, is associated with a smooth increase in density starting from the mid-mantle depth to the core-mantle boundary (CMB). The transition also yields softening in the elastic moduli and an increase in the thermal expansivity over the transition zone in the lower mantle. Although there is not yet robust experimental evidence for spin-transition induced density change in the perovskite (Pv) phase (the major constituent mineral in the lower mantle), the spin transition in the octahedral (B) site in Al-free perovskite causes a bulk modulus hardening (increase in the bulk modulus) in the mineral. We have incorporated these physical processes into high resolution 3D-spherical control volume models for mantle convection. A series of numerical experiments explore how the electronic spin transition in iron modifies the mantle flow, and in particular the fate of sinking cold slabs. Such mid-mantle stagnations are prevalent globally in seismic tomographic inversions, but previous explanations for their existence are not satisfactory. Employing density anomalies from the iron spin transition in ferropericlase and density anomaly models for perovskite, we study the influence of the spin transition in the minerals of the lower mantle on mantle flow. Our model results reveal that while the spin transition-induced property variations in ferropericlase enhance mixing in the lower depths of the mantle, the density anomaly arising from the hardening in the bulk modulus of Al-free perovskite can be effective in slowing the descent of slabs and may cause stagnation at mid-mantle levels. A viscosity hill in the lower mantle may further enhance the stagnation

  13. Enhanced in Vitro and in Vivo Performance of Mg-Zn-Y-Nd Alloy Achieved with APTES Pretreatment for Drug-Eluting Vascular Stent Application.

    Science.gov (United States)

    Liu, Jing; Zheng, Bo; Wang, Pei; Wang, Xingang; Zhang, Bin; Shi, Qiuping; Xi, Tingfei; Chen, Ming; Guan, Shaokang

    2016-07-20

    Bioabsorbable magnesium alloys are becoming prominent as temporary functional implants, as they avoid the risks generated by permanent metallic implants such as persistent inflammation and late restenosis. Nevertheless, the overfast corrosion of Mg alloys under physiological conditions hinders their wider application as medical implant materials. Here we investigate a simple one-step process to introduce a cross-linked 3-amino-propyltrimethoxysilane (APTES) silane physical barrier layer on the surface of Mg-Zn-Y-Nd alloys prior to electrostatic spraying with rapamycin-eluting poly(lactic-co-glycolic acid) (PLGA) layer. Surface microstructure was characterized by scanning electron microscope and Fourier transform infrared spectroscopy. Nanoscratch test verified the superior adhesion strength of PLGA coating in the group pretreated with APTES. Electrochemical tests combined with long-term immersion results suggested that the preferable in vitro anticorrosion behavior could be achieved by dense APTES barrier. Cell morphology and proliferation data demonstrated that APTES pretreated group resulted in remarkably preferable compatibility for both human umbilical vein endothelial cells and vascular smooth muscle cells. On the basis of excellent in vitro mechenical property, the animal study on the APTES pretreated Mg-Zn-Y-Nd stent implanted into porcine coronary arteries confirmed benign tissue compatibility as well as re-endothelialization without thrombogenesis or in-stent restenosis at six-month followup.

  14. Highly Functional TNTs with Superb Photocatalytic, Optical, and Electronic Performance Achieving Record PV Efficiency of 10.1% for 1D-Based DSSCs.

    Science.gov (United States)

    Qadir, Muhammad Bilal; Li, Yuewen; Sahito, Iftikhar Ali; Arbab, Alvira Ayoub; Sun, Kyung Chul; Mengal, Naveed; Memon, Anam Ali; Jeong, Sung Hoon

    2016-09-01

    Different nanostructures of TiO2 play an important role in the photocatalytic and photoelectronic applications. TiO2 nanotubes (TNTs) have received increasing attention for these applications due to their unique physicochemical properties. Focusing on highly functional TNTs (HF-TNTs) for photocatalytic and photoelectronic applications, this study describes the facile hydrothermal synthesis of HF-TNTs by using commercial and cheaper materials for cost-effective manufacturing. To prove the functionality and applicability, these TNTs are used as scattering structure in dye-sensitized solar cells (DSSCs). Photocatalytic, optical, Brunauer-Emmett-Teller (BET), electrochemical impedance spectrum, incident-photon-to-current efficiency, and intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy characterizations are proving the functionality of HF-TNTs for DSSCs. HF-TNTs show 50% higher photocatalytic degradation rate and also 68% higher dye loading ability than conventional TNTs (C-TNTs). The DSSCs having HF-TNT and its composite-based multifunctional overlayer show effective light absorption, outstanding light scattering, lower interfacial resistance, longer electron lifetime, rapid electron transfer, and improved diffusion length, and consequently, J SC , quantum efficiency, and record photoconversion efficiency of 10.1% using commercial N-719 dye is achieved, for 1D-based DSSCs. These new and highly functional TNTs will be a concrete fundamental background toward the development of more functional applications in fuel cells, dye-sensitized solar cells, Li-ion batteries, photocatalysis process, ion-exchange/adsorption process, and photoelectrochemical devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Heat transfer in boundary layer stagnation-point flow towards a shrinking sheet with non-uniform heat flux

    Institute of Scientific and Technical Information of China (English)

    Krishnendu Bhattacharyya

    2013-01-01

    In this paper,the effect of non-uniform heat flux on heat transfer in boundary layer stagnation-point flow over a shrinking sheet is studied.The variable boundary heat fluxes are considered of two types:direct power-law variation with the distance along the sheet and inverse power-law variation with the distance.The governing partial differential equations (PDEs) are transformed into non linear self-similar ordinary differential equations (ODEs) by similarity transformations,and then those are solved using very efficient shooting method.The direct variation and inverse variation of heat flux along the sheet have completely different effects on the temperature distribution.Moreover,the heat transfer characteristics in the presence of non-uniform heat flux for several values of physical parameters are also found to be interesting.

  16. MHD Stagnation-Point Flow and Heat Transfer with Effects of Viscous Dissipation, Joule Heating and Partial Velocity Slip.

    Science.gov (United States)

    Yasin, Mohd Hafizi Mat; Ishak, Anuar; Pop, Ioan

    2015-12-09

    The steady two-dimensional stagnation-point flow and heat transfer past a permeable stretching/shrinking sheet with effects of viscous dissipation, Joule heating and partial velocity slip in the presence of a magnetic field is investigated. The partial differential equations are reduced to nonlinear ordinary differential equations by using a similarity transformation, before being solved numerically by shooting technique. Results indicate that the skin friction coefficient and the local Nusselt number increase as magnetic parameter increases. It is found that for the stretching sheet the solution is unique while for the shrinking sheet there exist nonunique solutions (dual solutions) in certain range of parameters. The stability analysis shows that the upper branch solution is stable while the lower branch solution is unstable.

  17. MHD Stagnation Point Flow of Williamson Fluid over a Stretching Cylinder with Variable Thermal Conductivity and Homogeneous/Heterogeneous Reaction

    Science.gov (United States)

    Bilal, M.; Sagheer, M.; Hussain, S.; Mehmood, Y.

    2017-06-01

    The present study reveals the effect of homogeneous/hetereogeneous reaction on stagnation point flow of Williamson fluid in the presence of magnetohydrodynamics and heat generation/absorption coefficient over a stretching cylinder. Further the effects of variable thermal conductivity and thermal stratification are also considered. The governing partial differential equations are converted to ordinary differential equations with the help of similarity transformation. The system of coupled non-linear ordinary differential equations is then solved by shooting technique. MATLAB shooting code is validated by comparison with the previously published work in limiting case. Results are further strengthened when the present results are compared with MATLAB built-in function bvp4c. Effects of prominent parameters are deliberated graphically for the velocity, temperature and concentration profiles. Skin-friction coefficient and Nusselt number for the different parameters are investigated with the help of tables.

  18. Stagnation Point Flow of a Nanofluid toward an Exponentially Stretching Sheet with Nonuniform Heat Generation/Absorption

    Directory of Open Access Journals (Sweden)

    A. Malvandi

    2013-01-01

    Full Text Available This paper deals with the steady two-dimensional stagnation point flow of nanofluid toward an exponentially stretching sheet with nonuniform heat generation/absorption. The employed model for nanofluid includes two-component four-equation nonhomogeneous equilibrium model that incorporates the effects of Brownian diffusion and thermophoresis simultaneously. The basic partial boundary layer equations have been reduced to a two-point boundary value problem via similarity variables and solved analytically via HAM. Effects of governing parameters such as heat generation/absorption λ, stretching parameter ε, thermophoresis , Lewis number Le, Brownian motion , and Prandtl number Pr on heat transfer and concentration rates are investigated. The obtained results indicate that in contrast with heat transfer rate, concentration rate is very sensitive to the abovementioned parameters. Also, in the case of heat generation , despite concentration rate, heat transfer rate decreases. Moreover, increasing in stretching parameter leads to a gentle rise in both heat transfer and concentration rates.

  19. An HAM Analysis of Stagnation-Point Flow of a Nanofluid over a Porous Stretching Sheet with Heat Generation

    Directory of Open Access Journals (Sweden)

    A. Malvandi

    2014-01-01

    Full Text Available Steady two-dimensional stagnation point flow and heat transfer of a nanofluid over a porous stretching sheet investigated analytically using the Homotopy Analysis Method (HAM. The employed model for nanofluid includes two-component four-equation non-homogeneous equilibrium model that incorporates the effects of Brownian diffusion and thermophoresis simultaneously. The basic partial boundary layer equations have been reduced to a two-point boundary value problem via similarity variables. The effects of thermophoresis number ( , Brownian motion number ( , suction/injection parameter ( , source/sink parameter ( , permeability parameter ( , stretching parameter and Lewis number ( on the temperature and nanoparticle concentration profiles are studied in detail. Moreover, special attention is paid on the variations of reduced Nusselt and Sherwood number on the affects of physical parameters. The obtained results indicate that for , reduced Sherwood number remains constant however, corresponds to negative Sherwood number, i.e. concentration rate is reversed.

  20. Stagnation-Point Flow and Heat Transfer over a Nonlinearly Stretching/Shrinking Sheet in a Micropolar Fluid

    Directory of Open Access Journals (Sweden)

    Khairy Zaimi

    2014-01-01

    Full Text Available This paper considers the problem of a steady two-dimensional stagnation-point flow and heat transfer of an incompressible micropolar fluid over a nonlinearly stretching/shrinking sheet. A similarity transformation is employed to convert the partial differential equations into nonlinear ordinary ones which are then solved numerically using a shooting method. Numerical results obtained are presented graphically, showing the effects of the micropolar or material parameter and the stretching/shrinking parameter on the flow field and heat transfer characteristics. The dual solutions are found to exist in a limited range of the stretching/shrinking parameter for the shrinking case, while unique solutions are possible for all positive values of the stretching/shrinking parameter (stretching case. It is also observed that the skin friction coefficient and the magnitude of the local Nusselt number increase as the material parameter increases.

  1. Effects of ohmic heating and viscous dissipation on steady MHD flow near a stagnation point on an isothermal stretching sheet

    Directory of Open Access Journals (Sweden)

    Sharma Pushkar Raj

    2009-01-01

    Full Text Available Aim of the paper is to investigate effects of ohmic heating and viscous dissipation on steady flow of a viscous incompressible electrically conducting fluid in the presence of uniform transverse magnetic field and variable free stream near a stagnation point on a stretching non-conducting isothermal sheet. The governing equations of continuity, momentum, and energy are transformed into ordinary differential equations and solved numerically using Runge-Kutta fourth order with shooting technique. The velocity and temperature distributions are discussed numerically and presented through graphs. Skin-friction coefficient and the Nusselt number at the sheet are derived, discussed numerically, and their numerical values for various values of physical parameters are compared with earlier results and presented through tables.

  2. MHD Stagnation-Point Flow and Heat Transfer with Effects of Viscous Dissipation, Joule Heating and Partial Velocity Slip

    Science.gov (United States)

    Mat Yasin, Mohd Hafizi; Ishak, Anuar; Pop, Ioan

    2015-12-01

    The steady two-dimensional stagnation-point flow and heat transfer past a permeable stretching/shrinking sheet with effects of viscous dissipation, Joule heating and partial velocity slip in the presence of a magnetic field is investigated. The partial differential equations are reduced to nonlinear ordinary differential equations by using a similarity transformation, before being solved numerically by shooting technique. Results indicate that the skin friction coefficient and the local Nusselt number increase as magnetic parameter increases. It is found that for the stretching sheet the solution is unique while for the shrinking sheet there exist nonunique solutions (dual solutions) in certain range of parameters. The stability analysis shows that the upper branch solution is stable while the lower branch solution is unstable.

  3. Characteristics of Homogeneous-Heterogeneous Reactions and Melting Heat Transfer in the Stagnation Point flow of Jeffrey Fluid

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2016-01-01

    Full Text Available This work focuses on melting heat transfer in the stagnation point flow of Jeffrey fluid past an impermeable stretching cylinder with homogeneous-heterogeneous reactions. Characteristics of magnetohydrodynamic flow are explored in presence of heat generation/absorption. Diffusion coefficients of species A and B are taken of the same size. Heat released during chemical reaction is negligible. A system of ordinary differential equations is obtained by using suitable transformations. Convergent series solutions are derived. Impacts of various pertinent parameters on the velocity, temperature and concentration distributions are discussed. Numerical values of skin friction coefficient and Nusselt number are computed and analyzed. Present results are compared with the previous published data.

  4. Mixed convection flow of a viscoelastic fluid near the orthogonal stagnation-point on a vertical surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [Department of Mathematics and Statistics, University of Regina, Regina, SK S4S 0A2 (Canada); Labropulu, F. [Luther College e Mathematics, University of Regina, Regina, SK S4S 0A2 (Canada); Pop, I. [Faculty of Mathematics, University of Cluj, R-3400 Cluj, CP 253 (Romania)

    2011-09-15

    An analysis of the steady mixed convection flow of a viscoelastic fluid stagnating orthogonally on a heated or cooled vertical flat plate has been studied. Using similarity variables, the governing equations are transformed into a system of two coupled non-linear ordinary differential equations. The resulting equations are then solved numerically using the spectral method. It is observed that the skin friction coefficient and the local heat transfer are decreasing when the Weissenberg number We is increasing in both assisting and opposing flow cases. On the other hand, the skin friction is decreasing and the local heat transfer is increasing when the Prandtl number Pr is increasing in the case of assisting flow. In the case of opposing flow, the skin friction and the local heat transfer are increasing as Pr is increasing. (authors)

  5. Analytical solution to stagnation-point flow and heat transfer over a stretching sheet based on homotopy analysis

    Institute of Scientific and Technical Information of China (English)

    Jing ZHU; Lian-cun ZHENG; Xin-xin ZHANG

    2009-01-01

    This paper is concerned with two-dimensional stagnation-point steady flow of an incompressible viscous fluid towards a stretching sheet whose velocity is proportional to the distance from the slit. The governing system of partial differential equations is first transformed into a system of dimensionless ordinary differential equations. Analytical solutions of the velocity distribution and dimensionless temperature profiles are obtained for different ratios of free stream velocity and stretching velocity, Prandtl number, Eckert number and dimensionality index in series forms using homotopy analysis method(HAM).It is shown that a boundary layer is formed when the free stream velocity exceeds the stretching velocity, and an inverted boundary layer is formed when the free stream velocity is less than the stretching velocity. Graphs are presented to show the effects of different parameters.

  6. Group method analysis of mixed convection stagnation-point flow of non-Newtonian nanofluid over a vertical stretching surface

    Science.gov (United States)

    Nabwey, Hossam A.; Boumazgour, Mohamed; Rashad, A. M.

    2017-03-01

    The group method analysis is applied to study the steady mixed convection stagnation-point flow of a non-Newtonian nanofluid towards a vertical stretching surface. The model utilized for the nanofluid incorporates the Brownian motion and thermophoresis effects. Applying the one-parameter transformation group which reduces the number of independent variables by one and thus, the system of governing partial differential equations has been converted to a set of nonlinear ordinary differential equations, and these equations are then computed numerically using the implicit finite-difference scheme. Comparison with previously published studies is executed and the results are found to be in excellent agreement. Results for the velocity, temperature, and the nanoparticle volume fraction profiles as well as the local skin-friction coefficient and local Nusselt number are presented in graphical and tabular forms, and discussed for different values of the governing parameters to show interesting features of the solutions.

  7. Relationship between Gastro-esophageal Reflux Disease and the Stagnation Theory%从郁论治胃食管反流病探析

    Institute of Scientific and Technical Information of China (English)

    刘仁昌; 王光铭; 李春婷

    2012-01-01

    从气结为郁、痰积为郁、湿蕴为郁、瘀留为郁四方面阐述了郁之理论在胃食管反流病中形成的机理,以疏肝行气法、化痰降浊法、清热除湿法、祛瘀通络法作为开郁以治疗胃食管反流病的具体治法,并为其治法在临床治疗中提供了佐证.%To explain the importance of stagnation theory in treating gastro-esophageal reflux disease by four parts which is stagnation of Qi, stagnation of Phlegm, stagnation of dampness and blood stasis. With the evidence in how to treat gastro-esophageal reflux disease in clinic, the main treatment is smoothing the liver Qi, eliminating the phlegm, clearing away dampness-heat, removing the blood stasis to free collaterals.

  8. Deposition of oral bacteria and polystyrene particles to quartz and dental enamel in a parallel plate and stagnation point flow chamber

    NARCIS (Netherlands)

    Yang, JL; Belder, GF; Busscher, HJ; Bos, R.R.M.

    1999-01-01

    The aim of this paper is to determine to what extent (i) deposition of oral bacteria and polystyrene particles, (ii) onto quartz and dental enamel with and without a salivary conditioning film, (iii) in a parallel plate (PP) and stagnation point (SP) flow chamber and at common Peclet numbers are

  9. Evidence for Subglacial Deformation and Deposition during a Complete Advance-Stagnation Cycle of Kötlujökull, Iceland – A Case Study

    DEFF Research Database (Denmark)

    Klint, K E S; Richardt, N; Krüger, Johannes

    2010-01-01

    deformation and deposition from dynamically active ice, (4) subglacial deposition from stagnant ice and (5) supraglacial re-deposition in dead-ice environment during de-icing. This complete sedimentary sequence represents a single glacier advance-stagnation cycle. The melt-out till displays moderate...

  10. Bacterial deposition to fluoridated and non-fluoridated polyurethane coatings with different elastic modulus and surface tension in a parallel plate and a stagnation point flow chamber

    NARCIS (Netherlands)

    Bakker, D.P.; Huijs, F.M.; Vries, J. de; Klijnstra, J.W.; Busscher, H.J.; Mei, H.C. van der

    2003-01-01

    Deposition of three marine bacterial strains with different cell surface hydrophobicities from artificial seawater to polyurethane coatings on glass with different surface tensions and elastic modulus was studied in situ in a parallel plate (PP) and stagnation point (SP) flow chamber. Different surf

  11. Achieving high performance electric field induced strain: a rational design of hyperbranched aromatic polyamide functionalized graphene-polyurethane dielectric elastomer composites.

    Science.gov (United States)

    Chen, Tian; Qiu, Jinhao; Zhu, Kongjun; Li, Jinhuan; Wang, Jingwen; Li, Shuqin; Wang, Xiaoliang

    2015-03-26

    Dielectric elastomers have great potentials as flexible actuators in micro-electromechanical systems (MEMS) due to their large deformation, light weight, mechanical compliancy, and low cost. The low dielectric constant of these elastomers requires a rather high voltage electric field, which has greatly limited their applications. In this work, a diaphragm-type flexible microactuator comprising a hyperbranched aromatic polyamide functionalized graphene (HAPFG) filler embedded into the polyurethane (PU) dielectric elastomer matrix is described. The rational designed HAPFG sheets exhibits uniform dispersion in PU matrix and strong adhesion with the matrix by hydrogen-bond coupling. Consequently, the HAPFG-PU composites possess high dielectric performance and low loss modulus. The effect of hyperbranched aromatic polyamide functionalized graphene on high voltage electric field induced strain was experimentally investigated using the Fotonic sensor. The high electric field response of the composite was discussed by applying different kinds of alternating-current field. In addition, a comparison of the breakdown strength between the HAPFG-PU composite and the pure PU was carried out.

  12. Nanoscale Polysulfides Reactors Achieved by Chemical Au-S Interaction: Improving the Performance of Li-S Batteries on the Electrode Level.

    Science.gov (United States)

    Fan, Chao-Ying; Xiao, Pin; Li, Huan-Huan; Wang, Hai-Feng; Zhang, Lin-Lin; Sun, Hai-Zhu; Wu, Xing-Long; Xie, Hai-Ming; Zhang, Jing-Ping

    2015-12-23

    In this work, the chemical interaction of cathode and lithium polysulfides (LiPSs), which is a more targeted approach for completely preventing the shuttle of LiPSs in lithium-sulfur (Li-S) batteries, has been established on the electrode level. Through simply posttreating the ordinary sulfur cathode in atmospheric environment just for several minutes, the Au nanoparticles (Au NPs) were well-decorated on/in the surface and pores of the electrode composed of commercial acetylene black (CB) and sulfur powder. The Au NPs can covalently stabilize the sulfur/LiPSs, which is advantageous for restricting the shuttle effect. Moreover, the LiPSs reservoirs of Au NPs with high conductivity can significantly control the deposition of the trapped LiPSs, contributing to the uniform distribution of sulfur species upon charging/discharging. The slight modification of the cathode with <3 wt % Au NPs has favorably prospered the cycle capacity and stability of Li-S batteries. Moreover, this cathode exhibited an excellent anti-self-discharge ability. The slight decoration for the ordinary electrode, which can be easily accessed in the industrial process, provides a facile strategy for improving the performance of commercial carbon-based Li-S batteries toward practical application.

  13. Treatment Experience of Acne by the Methods of Eliminating Stagnation and Anthracoma%散结消痈治疗痤疮经验

    Institute of Scientific and Technical Information of China (English)

    周宝宽; 周探

    2012-01-01

    Objective :To summarize treatment experience of acne by the. Methods of eliminating stagnation and anthracoma, and the decoctions of Miraculous decoction for regional infection, Lianqiao Baidu Powder, Wuwei Xiaodu Decoction, Simiao Yong'an decoction. Methods : Discuss principles, methods, formulas and medicinals of hypomnesia caused by sexual overindulgence based on medical records. Result: Acne with lung meridian wind-heat, toxic heat stagnanl was treated by Miraculous decoction for regional infection; acne with wind heat toxin attacking, toxic heat stagnation, qi stagnation blood stasis was treated by Lianqiao Baidu Powder; acne with lung meridian wind-heat, burn infection stagnation was treated by Wuwei Xiaodu Decoction;acne with toxic he.at flourishing and obstructing meridian and vessels was treated with Simiao Yong'an Decoction. Those methods and decoction show a better therapeutic effect on acne. Conclusions : Methods of eliminating stagnation and anthracoma have a good effect on acne.%目的:总结仙方活命饮、连翘败毒散、五味消毒饮、四妙勇安汤四方散结消痈治疗痤疮经验.方法:以医案形式,融理、法、方、药为一体进行阐述.结果:仙方活命饮加减治疗肺经风热、热毒壅滞型痤疮;连翘败毒散治疗风热毒邪上攻、热毒壅结、气血瘀滞型痤疮;五味消毒饮治疗肺经风热、火毒结聚型痤疮;四妙勇安汤治疗热毒炽盛、瘀阻经脉型痤疮,均取得满意疗效.结论:散结消痈治疗痤疮,疗效满意.

  14. The Predictiveness of Achievement Goals

    Directory of Open Access Journals (Sweden)

    Huy P. Phan

    2013-11-01

    Full Text Available Using the Revised Achievement Goal Questionnaire (AGQ-R (Elliot & Murayama, 2008, we explored first-year university students’ achievement goal orientations on the premise of the 2 × 2 model. Similar to recent studies (Elliot & Murayama, 2008; Elliot & Thrash, 2010, we conceptualized a model that included both antecedent (i.e., enactive learning experience and consequence (i.e., intrinsic motivation and academic achievement of achievement goals. Two hundred seventy-seven university students (151 women, 126 men participated in the study. Structural equation modeling procedures yielded evidence that showed the predictive effects of enactive learning experience and mastery goals on intrinsic motivation. Academic achievement was influenced intrinsic motivation, performance-approach goals, and enactive learning experience. Enactive learning experience also served as an antecedent of the four achievement goal types. On the whole, evidence obtained supports the AGQ-R and contributes, theoretically, to 2 × 2 model.

  15. Botulinum toxin A for oral cavity cancer patients: in microsurgical patients BTX injections in major salivary glands temporarily reduce salivary production and the risk of local complications related to saliva stagnation.

    Science.gov (United States)

    Corradino, Bartolo; Di Lorenzo, Sara; Moschella, Francesco

    2012-10-24

    In patients suffering from oral cavity cancer surgical treatment is complex because it is necessary to remove carcinoma and lymph node metastasis (through a radical unilateral or bilateral neck dissection) and to reconstruct the affected area by means of free flaps. The saliva stagnation in the post-operative period is a risk factor with regard to local complications. Minor complications related to saliva stagnation (such as tissue maceration and wound dehiscence) could become major complications compromising the surgery or the reconstructive outcome. In fact the formation of oro-cutaneous fistula may cause infection, failure of the free flap, or the patient’s death with carotid blow-out syndrome. Botulinum injections in the major salivary glands, four days before surgery, temporarily reduces salivation during the healing stage and thus could reduce the incidence of saliva-related complications. Forty three patients with oral cancer were treated with botulinum toxin A. The saliva quantitative measurement and the sialoscintigraphy were performed before and after infiltrations of botulinum toxin in the major salivary glands. In all cases there was a considerable, but temporary, reduction of salivary secretion. A lower rate of local complications was observed in the post-operative period. The salivary production returned to normal within two months, with minimal side effects and discomfort for the patients. The temporary inhibition of salivary secretion in the post-operative period could enable a reduction in saliva-related local complications, in the incidence of oro-cutaneous fistulas, and improve the outcome of the surgery as well as the quality of residual life in these patients.

  16. Botulinum Toxin A for Oral Cavity Cancer Patients: In Microsurgical Patients BTX Injections in Major Salivary Glands Temporarily Reduce Salivary Production and the Risk of Local Complications Related to Saliva Stagnation

    Directory of Open Access Journals (Sweden)

    Bartolo Corradino

    2012-10-01

    Full Text Available In patients suffering from oral cavity cancer surgical treatment is complex because it is necessary to remove carcinoma and lymph node metastasis (through a radical unilateral or bilateral neck dissection and to reconstruct the affected area by means of free flaps. The saliva stagnation in the post-operative period is a risk factor with regard to local complications. Minor complications related to saliva stagnation (such as tissue maceration and wound dehiscence could become major complications compromising the surgery or the reconstructive outcome. In fact the formation of oro-cutaneous fistula may cause infection, failure of the free flap, or the patient’s death with carotid blow-out syndrome. Botulinum injections in the major salivary glands, four days before surgery, temporarily reduces salivation during the healing stage and thus could reduce the incidence of saliva-related complications. Forty three patients with oral cancer were treated with botulinum toxin A. The saliva quantitative measurement and the sialoscintigraphy were performed before and after infiltrations of botulinum toxin in the major salivary glands. In all cases there was a considerable, but temporary, reduction of salivary secretion. A lower rate of local complications was observed in the post-operative period. The salivary production returned to normal within two months, with minimal side effects and discomfort for the patients. The temporary inhibition of salivary secretion in the post-operative period could enable a reduction in saliva-related local complications, in the incidence of oro-cutaneous fistulas, and improve the outcome of the surgery as well as the quality of residual life in these patients.

  17. Slab stagnation and buckling in the mantle transition zone: Rheology, phase transition, trench migration, and seismic structure

    Science.gov (United States)

    Bina, Craig; Cizkova, Hana

    2014-05-01

    observations better than a flat-lying slab (Zhang et al., 2013). Earthquake hypocentral distributions and focal mechanisms may provide clearer insights into slab buckling, as they appear to vary systematically across regions of slab stagnation (Fukao and Obayashi, 2013). Stress fields computed from our dynamical models may help to illuminate such observations. References: Bina, C.R., and H. Kawakatsu, Buoyancy, bending, and seismic visibility in deep slab stagnation, Phys. Earth Planet. Inter., 183, 330-340, 2010. Čížková, H., and C.R. Bina, Effects of mantle and subduction-interface rheologies on slab stagnation and trench rollback, Earth Planet. Sci. Lett., 379, 95-103, 2013. Fukao, Y., and M. Obayashi, Deepest hypocentral distributions associated with stagnant slabs and penetrated slabs, Fall Meeting Abstracts, AGU, DI14A-01, 2013. Li, Z.-H., and N.M. Ribe, Dynamics of free subduction from 3-D boundary element modeling, J. Geophys. Res., 117, B06408. Matthews, D.C., L. Zheng, and R.G. Gordon, Do trenches advance? Fall Meeting Abstracts, AGU, T43D-2682, 2013. Zhang, Y., Y. Wang, Y. Wu, C. Bina, Z. Jin, and S. Dong, Phase transitions of harzburgite and buckled slab under eastern China, Geochem. Geophys. Geosys., 14, 1182-1199, 2013.

  18. Using 1D theory to understand 3D stagnation of a wire-array Z pinch in the absence of radiation

    Science.gov (United States)

    Yu, Edmund

    2015-11-01

    Many high-energy-density systems implode towards the axis of symmetry, where it collides on itself, forming a hot plasma. However, experiments show these imploding plasmas develop three-dimensional (3D) structures. As a result, the plasma cannot completely dissipate its kinetic energy at stagnation, instead retaining significant 3D flow. A useful tool for understanding the effects of this residual flow is 3D simulation, but the amount and complexity of information can be daunting. To address this problem, we explore the connection between 3D simulation and one-dimensional (1D) theory. Such a connection, if it exists, is mutually beneficial: 1D theory can provide a clear picture of the underlying dynamics of 3D stagnation. On the other hand, deviations between theory and simulation suggest how 1D theory must be modified to account for 3D effects. In this work, we focus on a 3D, magnetohydrodynamic simulation of a compact wire-array Z pinch. To provide a simpler background against which to test our ideas, we artificially turn off radiation during the stagnation phase. Examination of the initial accumulation of mass on axis reveals oblique collision between jets, shock accretion, and vortex formation. Despite evidence for shock-dominated stagnation, a 1D shockless stagnation solution is more appropriate for describing the global dynamics, in that it reproduces the increase of on-axis density with time. However, the 1D solution must be modified to account for 3D effects: the flows suggest enhanced thermal transport as well as centrifugal force. Upon reaching peak compression, the stagnation transitions to a second phase, in which the high-pressure core on axis expands outward into the remaining imploding plasma. During this phase, a 1D shock solution describes the growth of the shock accretion region, as well as the decrease of on-axis density with time. However, the effect of 3D flows is still present: the on-axis temperature does not cool during expansion, which

  19. Performance Based Logistics For Achieving Affordable Readiness

    Science.gov (United States)

    2015-02-01

    manager ( PSM ), engineering, finance, contracting and other government representatives are required to coordinate and collaborate with each other...and procurement (not O&M) appropriations in his acquisition checkbook. There is the PSM , who serves as the PM’s representative and lead in the...to facilitate long-term PBL contracts. The warfighter, PM and PSM usually have little control of DWCF. Add the pos- sibility of joint Service or

  20. Achieving Performance-based Lifecycle Management

    Science.gov (United States)

    2009-04-22

    GAO. (2008b). Neil Abercrombie, Jim Saxton, Subcommittee on Air and Land Forces Committee on Armed Services, House of Representatives, and Gene...Taylor, Roscoe Bartlett Subcommittee on Sea power and Expeditionary Forces Committee on Armed Services, House of Representative (GAO-08-884R