WorldWideScience

Sample records for thermal challenge problem

  1. Challenging problems in algebra

    CERN Document Server

    Posamentier, Alfred S

    1996-01-01

    Over 300 unusual problems, ranging from easy to difficult, involving equations and inequalities, Diophantine equations, number theory, quadratic equations, logarithms, more. Detailed solutions, as well as brief answers, for all problems are provided.

  2. Challenging problems in geometry

    CERN Document Server

    Posamentier, Alfred S

    1996-01-01

    Collection of nearly 200 unusual problems dealing with congruence and parallelism, the Pythagorean theorem, circles, area relationships, Ptolemy and the cyclic quadrilateral, collinearity and concurrency and more. Arranged in order of difficulty. Detailed solutions.

  3. Toxaphene: a challenging analytical problem

    NARCIS (Netherlands)

    de Geus, H.J.; Wester, P.G.; Schelvis, A.; de Boer, J.; Brinkman, U.A.T.

    2000-01-01

    The analysis of toxaphene, a highly complex mixture of chlorinated bornanes, bornenes and camphenes, is a challenging problem, especially as individual congeners are present at trace levels in biota and other relevant samples. The complicated nomenclature of the compounds of interest is briefly

  4. Special problems: LBB, thermal effects

    International Nuclear Information System (INIS)

    Lin Chiwen

    2001-01-01

    This section presents the discussion of special problems in the reactor coolant system design, including LBB and thermal effects. First, the categories of fracture mechanics technology applicable to LBB is discussed. Two categories of fracture mechanics, namely: linear-elastic fracture mechanics (LEFM) and elastic-plastic fracture mechanics (EPFM) are discussed specifically. Next, basic concepts of LEFM are discussed. This will be followed by a discussion of EPFM, with more specific discussion of the methodology currently acceptable to NRC, with the emphasis on the J-integral approach. This is followed by a discussion of the NRC position and recommendations and basic requirements laid out by NRC. A specific example of LBB application to WPWR piping is used to identify the key steps to be followed, in order to satisfy the recommendations and requirements of NRC. An application of LBB to the WPWR reactor coolant loop piping is provided as further illustration of the methodology. This section focuses on the thermal effects which have not been addressed earlier, and the thermal effects which have caused particular concerns on potential reactor degradations, such as pressurized thermal shocks. The organization of this section is divided into the following subsections: linear-elastic fracture mechanics (LEFM); elastic-plastic fracture mechanics (EPFM); J concepts; NRC recommendations and requirements on the application of LBB; two specific applications of LBB to WPWR piping; PWR internals degradation; thermal fatigue considerations; a case study of pressurized thermal shock

  5. Image Processing: Some Challenging Problems

    Science.gov (United States)

    Huang, T. S.; Aizawa, K.

    1993-11-01

    Image processing can be broadly defined as the manipulation of signals which are inherently multidimensional. The most common such signals are photographs and video sequences. The goals of processing or manipulation can be (i) compression for storage or transmission; (ii) enhancement or restoration; (iii) analysis, recognition, and understanding; or (iv) visualization for human observers. The use of image processing techniques has become almost ubiquitous; they find applications in such diverse areas as astronomy, archaeology, medicine, video communication, and electronic games. Nonetheless, many important problems in image processing remain unsolved. It is the goal of this paper to discuss some of these challenging problems. In Section I, we mention a number of outstanding problems. Then, in the remainder of this paper, we concentrate on one of them: very-low-bit-rate video compression. This is chosen because it involves almost all aspects of image processing.

  6. Aleph Field Solver Challenge Problem Results Summary

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Russell [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, Stan Gerald [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Aleph models continuum electrostatic and steady and transient thermal fields using a finite-element method. Much work has gone into expanding the core solver capability to support enriched modeling consisting of multiple interacting fields, special boundary conditions and two-way interfacial coupling with particles modeled using Aleph's complementary particle-in-cell capability. This report provides quantitative evidence for correct implementation of Aleph's field solver via order- of-convergence assessments on a collection of problems of increasing complexity. It is intended to provide Aleph with a pedigree and to establish a basis for confidence in results for more challenging problems important to Sandia's mission that Aleph was specifically designed to address.

  7. Thermal shock problems in a plate

    International Nuclear Information System (INIS)

    Takeuti, Y.; Furukawa, T.

    1981-01-01

    The problems considered are coupled dynamic thermoelastic analysis in a plate. First we try to examine a problem of the coupled dynamic thermal stress problem with small time approximation for the finite region. Next, we treatise both effects individually by pursuing rigorous anaylsis without small time approximation. Finally we consider thermal shock problems in a plate against different values of heat transfer coefficient (Biot's number) for the time. In conclusion, for usual materials, the inertia effect may be disregarded in the pure thermal problems in contrast to the coupling effect which brings small lags in the temperature and thermal stress distributions. For the consideration of the maximum thermal stress problems, Manson's uncoupled quasi-static results give enough approximation to the thermal shock problems without significant error from our numerical results. The analysis is developed by the use of Laplace transforms and several useful graphical illustrations are given. (orig./HP)

  8. Problem Analysis: Challenging All Learners

    Science.gov (United States)

    Garcia, Katie; Davis, Alicia

    2013-01-01

    In this article, Garcia and Davis describe problem analysis as the process of examining a given mathematics exercise to find ways in which the problem can be modified and extended to create a richer learning opportunity for students. Students are often reluctant to attempt what they perceive to be higher-order thinking problems, but problem…

  9. Challenging the assumptions for thermal sensation scales

    DEFF Research Database (Denmark)

    Schweiker, Marcel; Fuchs, Xaver; Becker, Susanne

    2016-01-01

    Scales are widely used to assess the personal experience of thermal conditions in built environments. Most commonly, thermal sensation is assessed, mainly to determine whether a particular thermal condition is comfortable for individuals. A seven-point thermal sensation scale has been used...... extensively, which is suitable for describing a one-dimensional relationship between physical parameters of indoor environments and subjective thermal sensation. However, human thermal comfort is not merely a physiological but also a psychological phenomenon. Thus, it should be investigated how scales for its...... assessment could benefit from a multidimensional conceptualization. The common assumptions related to the usage of thermal sensation scales are challenged, empirically supported by two analyses. These analyses show that the relationship between temperature and subjective thermal sensation is non...

  10. Challenge Problem Development and Evaluation Management

    National Research Council Canada - National Science Library

    Schrag, Robert

    2001-01-01

    This final report describes work performed by Information Extraction & Transport (IET), Inc. on Challenge Problem Development and Evaluation Management for the Defense Advanced Research Projects Agency's...

  11. CHASM Challenge Problem: Lagrangian Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hornung, R [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Keasler, J [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gokhale, M [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-09-10

    Computer simulations of many science and engineering problems require modeling the equations of hydrodynamics which describe the motion of materials relative to each other induced by various forces. Many important DoD simulation problems involve complex multi-material systems that undergo large deformations. Examples include the analysis of armor defense, penetration mechanics, blast effects, structural integrity, and conventional munitions such as shaped charges and explosively formed projectiles. Indeed, the original motivation for developing codes that solve the equations of hydrodynamics, herein referred to as “hydrocodes”, was to solve problems with defense applications. The FY2010 Requirements Analysis Report issued by the DoD High Performance Computing Modernization Program (HPCMP) Office shows that a major portion of DoD HPC activities involves hydrocodes [HPCMP2010]. The report surveyed 496 projects across the Services and various Agencies, representing 4,050 HPCMP users at more than 125 locations, including government, contractors, and academia, and grouped each project into one of ten categories.

  12. Two problems in thermal field theory

    Indian Academy of Sciences (India)

    In this talk, I review recent progress made in two areas of thermal field theory. In par- ticular, I discuss various approaches for the calculation of the quark gluon plasma thermodynamical properties, and the problem of its photon production rate. Keywords. Thermal field theory; quark-gluon plasma. PACS Nos 11.10.Wx; 12.38.

  13. Technological challenges in thermal plasma production

    International Nuclear Information System (INIS)

    Ramakrishnan, S.

    1995-01-01

    Thermal plasmas, generated by electric arc discharges, are used in a variety of industrial applications. The electric arc is a constricted electrical discharge with a high temperature in the range 6000-25,000 K. These characteristics are useful in plasma cutting, spraying, welding and specific areas of material processing. The thermal plasma technology is an enabling process technology and its status in the market depends upon its advantages over competing technologies. A few technological challenges to enhance the status of plasma technology are to improve the utilisation of the unique characteristics of the electric arc and to provide enhanced control of the process. In particular, new solutions are required for increasing the plasma-material interaction, controlling the electrode roots and controlling the thermal power generated by the arcing process. In this paper, the advantages of plasma technology, its constraints and future challenges for technology developments are highlighted. 36 refs., 14 figs

  14. Woman Entrepreneurship in Haryana: Challenges and Problems.

    OpenAIRE

    Sanchita

    2013-01-01

    The paper highlights the various problems and challenges faced by woman entrepreneurs while running the enterprises in the present competitive world of today which is both healthy as well as unhealthy. The problems of women entrepreneurs include working capital, distribution channel, sales promotion, electricity, human resources and competition with medium and large industries. To justify the need of the present study we have reviewed the literature. To draw policy implications we are require...

  15. Computer Simulation in Problems of Thermal Strength

    Directory of Open Access Journals (Sweden)

    Olga I. Chelyapina

    2012-05-01

    Full Text Available This article discusses informative technology of using graphical programming environment LabVIEW 2009 when calculating and predicting the thermal strength of materials with an inhomogeneous structure. Algorithm for processing the experimental data was developed as part of the problem.

  16. Quickfire Challenges to Inspire Problem Solving

    Science.gov (United States)

    Harper, Suzanne R.; Cox, Dana C.

    2017-01-01

    In the authors' attempts to incorporate problem solving into their mathematics courses, they have found that student ambition and creativity are often hampered by feelings of risk, as many students are conditioned to value a produced solution over the actual process of building one. Eliminating risk is neither possible nor desired. The challenge,…

  17. Crowdsourcing for Challenging Technical Problems - It Works!

    Science.gov (United States)

    Davis, Jeffrey R.

    2011-01-01

    The NASA Johnson Space Center Space Life Sciences Directorate (SLSD) and Wyle Integrated Science and Engineering (Wyle) will conduct a one-day business cluster at the 62nd IAC so that IAC attendees will understand the benefits of open innovation (crowdsourcing), review successful results of conducting technical challenges in various open innovation projects, and learn how an organization can effectively deploy these new problem solving tools to innovate more efficiently and effectively. Results from both the SLSD open innovation pilot program and the open innovation workshop conducted by the NASA Human Health and Performance Center will be discussed. NHHPC members will be recruited to participate in the business cluster (see membership http://nhhpc.nasa.gov) and as IAF members. Crowdsourcing may be defined as the act of outsourcing tasks that are traditionally performed by an employee or contractor to an undefined, generally large group of people or community (a crowd) in the form of an open call. The open call may be issued by the organization wishing to find a solution to a particular problem or complete a task, or by an open innovation service provider on behalf of that organization. In 2008, the SLSD, with the support of Wyle, established and implemented pilot projects in open innovation (crowdsourcing) to determine if these new internet-based platforms could indeed find solutions to difficult technical challenges. These unsolved technical problems were converted to problem statements, called Challenges by some open innovation service providers, and were then posted externally to seek solutions to these problems. In addition, an open call was issued internally to NASA employees Agency wide (11 Field Centers and NASA HQ) using an open innovation service provider crowdsourcing platform to post NASA challenges from each Center for the others to propose solutions). From 2008 to 2010, the SLSD issued 34 challenges, 14 externally and 20 internally. The 14 external

  18. Thermal fluctuation problems encountered in LMFRs

    International Nuclear Information System (INIS)

    Gelineau, O.; Sperandio, M.; Martin, P.; Ricard, J.B.; Martin, L.; Bougault, A.

    1994-01-01

    One of the most significant problems of LMFBRs deals with thermal fluctuations. The main reason is that LMFBRs operate with sodium coolant at very different temperatures which leads to the existence of several areas of transition between hot and cold sodium. These transitions areas which are the critical points, maybe found in the reactor block as well as in the secondary and auxiliary loops. The characteristics of these thermal fluctuations are not easy to quantify because of their complex (random) behaviour, and often demand the use of thermalhydraulic mock-up tests. A good knowledge of these phenomena is essential because of the potential high level of damage they can induce on structures. Two typical thermal fluctuation problems encountered on operation reactors are described. They were not originally anticipated at the design stage of the former Phenix and the latter Superphenix reactors. Description and the analyses performed to describe the damaging process are explained. A well known thermal fluctuation problem is presented. It is pointed out how the feedback from the damages observed on operating reactors is used to prevent the components from any high cycle fatigue

  19. Challenging problems and solutions in intelligent systems

    CERN Document Server

    Grzegorzewski, Przemysław; Kacprzyk, Janusz; Owsiński, Jan; Penczek, Wojciech; Zadrożny, Sławomir

    2016-01-01

    This volume presents recent research, challenging problems and solutions in Intelligent Systems– covering the following disciplines: artificial and computational intelligence, fuzzy logic and other non-classic logics, intelligent database systems, information retrieval, information fusion, intelligent search (engines), data mining, cluster analysis, unsupervised learning, machine learning, intelligent data analysis, (group) decision support systems, intelligent agents and multi-agent systems, knowledge-based systems, imprecision and uncertainty handling, electronic commerce, distributed systems, etc. The book defines a common ground for sometimes seemingly disparate problems and addresses them by using the paradigm of broadly perceived intelligent systems. It presents a broad panorama of a multitude of theoretical and practical problems which have been successfully dealt with using the paradigm of intelligent computing.

  20. Reliability engineering: Old problems and new challenges

    International Nuclear Information System (INIS)

    Zio, E.

    2009-01-01

    The first recorded usage of the word reliability dates back to the 1800s, albeit referred to a person and not a technical system. Since then, the concept of reliability has become a pervasive attribute worth of both qualitative and quantitative connotations. In particular, the revolutionary social, cultural and technological changes that have occurred from the 1800s to the 2000s have contributed to the need for a rational framework and quantitative treatment of the reliability of engineered systems and plants. This has led to the rise of reliability engineering as a scientific discipline. In this paper, some considerations are shared with respect to a number of problems and challenges which researchers and practitioners in reliability engineering are facing when analyzing today's complex systems. The focus will be on the contribution of reliability to system safety and on its role within system risk analysis

  1. Survival tactics within thermally-challenging roosts: heat tolerance ...

    African Journals Online (AJOL)

    Microclimates were thermally challenging, being very hot (>40°C) for several hours daily in summer and autumn, and cold (<10°C) for much of the night in winter Thermal preference tests revealed that the bats actively selected temperature zones (35°- 42°C) in which basal metabolic rate could be maintained, and above the ...

  2. Problems and challenges in social marketing.

    Science.gov (United States)

    Bloom, P N; Novelli, W D

    1981-01-01

    This article reviews the problems that arise when general marketing principles are applied to social programs. Social marketing is conceptualized as the design, implementation, and control of programs seeking to increase the acceptability of a social ideal or practice in a target group. These problems can occur in 8 basic decision-making areas: market analysis, market segmentation, product strategy development, pricing strategy development, channel strategy development, communications strategy development, organizational design and planning, and evaluation. Social marketers find that they have less good secondary data about their consumers, more problems obtaining valid and reliable measures of relevant variables, more difficulty sorting out the relative influence of determinants of consumer behavior, and more problems getting consumer research funded than marketers in the commercial sector. They tend to have less flexibility in shaping their products and more difficulty formulating product concepts. Problems associated with establishing, utilizing, and controlling distribution channels comprise another major difference between social and more conventional forms of marketing. Social marketers also find that their communications options are somewhat limited as a result of problems associated with use of paid advertisements, pressures not to use certain types of appeals in their messages, and the need to communicate large amounts of information in their messages. Moreover, social marketers must function in organizations where marketing activities are poorly understood, underappreciated, and inappropriately located. Finally, they face problems trying to define effectiveness measures or estimating the contribution their program has made toward the achievement of certain objectives. If all these problems are anticipated and handled creatively, social marketing efforts can succeed.

  3. Regional Film Culture: Challenges and Problems.

    Science.gov (United States)

    Fountain, Alan

    1978-01-01

    Discusses the relationship between general film culture and state intervention through the formation of a regional film policy and the funding of film exhibition, film education, and filmmaking in Britain. Suggests ways in which intervention can perpetuate the dominant cultural ideology and ways to identify, resist, and challenge present…

  4. Decommissioning: a problem or a challenge?

    Directory of Open Access Journals (Sweden)

    Mele Irena

    2004-01-01

    Full Text Available With the ageing of nuclear facilities or the reduced interest in their further operation, a new set of problems, related to the decommissioning of these facilities, has come into forefront. In many cases it turns out that the preparations for decommissioning have come too late, and that financial resources for covering decommissioning activities have not been provided. To avoid such problems, future liailities should be thoroughly estimated in drawing up the decommissioning and waste management programme for each nuclear facility in time, and financial provisions for implementing such programme should be provided. In this paper a presentation of current decommissioning experience in Slovenia is given. The main problems and difficulties in decommissioning of the Žirovski Vrh Uranium Mine are exposed and the lesson learned from this case is presented. The preparation of the decommissioning programme for the Nuclear Power Plant Krško is also described, and the situation at the TRIGA research reactor is briefly discussed.

  5. Fifty challenging problems in probability with solutions

    CERN Document Server

    Mosteller, Frederick

    1987-01-01

    Can you solve the problem of ""The Unfair Subway""? Marvin gets off work at random times between 3 and 5 p.m. His mother lives uptown, his girlfriend downtown. He takes the first subway that comes in either direction and eats dinner with the one he is delivered to. His mother complains that he never comes to see her, but he says she has a 50-50 chance. He has had dinner with her twice in the last 20 working days. Explain. Marvin's adventures in probability are one of the fifty intriguing puzzles that illustrate both elementary ad advanced aspects of probability, each problem designed to chall

  6. Army Science & Technology: Problems and Challenges

    Science.gov (United States)

    2012-03-01

    Boundary Conditions: Who: Small Units is COIN/Stability Operations What: Provide affordable real-time translations and d t di f b h i f l i th t i...Soldiers, Leaders and Units in complex tactical operations exceeds the Army’s current capability for home-station Challenge: Formulate a S& T program...Formulate a S& T program to capture, process and electronically a vance rauma managemen . disseminate near-real-time medical information on Soldier

  7. A suite of benchmark and challenge problems for enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark; Fu, Pengcheng; McClure, Mark; Danko, George; Elsworth, Derek; Sonnenthal, Eric; Kelkar, Sharad; Podgorney, Robert

    2017-11-06

    A diverse suite of numerical simulators is currently being applied to predict or understand the performance of enhanced geothermal systems (EGS). To build confidence and identify critical development needs for these analytical tools, the United States Department of Energy, Geothermal Technologies Office sponsored a Code Comparison Study (GTO-CCS), with participants from universities, industry, and national laboratories. A principal objective for the study was to create a community forum for improvement and verification of numerical simulators for EGS modeling. Teams participating in the study were those representing U.S. national laboratories, universities, and industries, and each team brought unique numerical simulation capabilities to bear on the problems. Two classes of problems were developed during the study, benchmark problems and challenge problems. The benchmark problems were structured to test the ability of the collection of numerical simulators to solve various combinations of coupled thermal, hydrologic, geomechanical, and geochemical processes. This class of problems was strictly defined in terms of properties, driving forces, initial conditions, and boundary conditions. The challenge problems were based on the enhanced geothermal systems research conducted at Fenton Hill, near Los Alamos, New Mexico, between 1974 and 1995. The problems involved two phases of research, stimulation, development, and circulation in two separate reservoirs. The challenge problems had specific questions to be answered via numerical simulation in three topical areas: 1) reservoir creation/stimulation, 2) reactive and passive transport, and 3) thermal recovery. Whereas the benchmark class of problems were designed to test capabilities for modeling coupled processes under strictly specified conditions, the stated objective for the challenge class of problems was to demonstrate what new understanding of the Fenton Hill experiments could be realized via the application of

  8. Conjoined Twins: Philosophical Problems and Ethical Challenges.

    Science.gov (United States)

    Savulescu, Julian; Persson, Ingmar

    2016-02-01

    We examine the philosophical and ethical issues associated with conjoined twins and their surgical separation. In cases in which there is an extensive sharing of organs, but nevertheless two distinguishable functioning brains, there are a number of philosophical and ethical challenges. This is because such conjoined twins: 1. give rise to puzzles concerning our identity, about whether we are identical to something psychological or biological; 2. force us to decide whether what matters from an ethical point of view is the biological life of our organisms or the existence of our consciousness or mind; 3. raise questions concerning when, if ever, it is morally acceptable to sacrifice one of us to save another; 4. force us to reflect on the conditions for ownership of organs and the justification of removal of organs for transplantation which causes the death of the donor; 5. raise questions about who should take decisions about life-risking treatments when this cannot be decided by patients themselves. We examine and suggest answers to these questions. © The Author 2015. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. An inverse heat transfer problem for optimization of the thermal ...

    Indian Academy of Sciences (India)

    This paper takes a different approach towards identification of the thermal process in machining, using inverse heat transfer problem. Inverse heat transfer method allows the closest possible experimental and analytical approximation of thermal state for a machining process. Based on a temperature measured at any point ...

  10. Problem of the lithium peroxide thermal stability

    International Nuclear Information System (INIS)

    Nefedov, R A; Ferapontov, Yu A; Kozlova, N P

    2016-01-01

    The behavior of lithium peroxide and lithium peroxide monohydrate samples under heating in atmospheric air was studied by the method of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). It was found that in the temperature range of 32°C to 82°C the interaction of lithium peroxides and steam with the formation of lithium peroxide monohydrate occurs, which was confirmed chemically and by X-ray Single-qualitative analysis. It was experimentally found that lithium peroxide starts to decompose into the lithium oxide and oxygen in the temperature range of 340 ÷ 348°C. It was established that the resulting thermal decomposition of lithium oxide, lithium peroxide at the temperature of 422°C melts with lithium carbonate eutecticly. The manifestation of polymorphism was not marked(seen or noticed) under the heating of studied samples of lithium peroxide and lithium peroxide monohydrate in the temperature range of 25°C ÷ 34°C. (paper)

  11. Thermal problems on high flux beam lines

    International Nuclear Information System (INIS)

    Avery, R.T.

    1983-09-01

    Wiggler and undulator magnets can provide very intense photon flux densities to beam line components. This paper addresses some thermal/materials consequences due to such impingement. The LBL/Exxon/SSRL hybrid-wiggler Beam Line VI now nearing operation will be able to provide up to approx. 7 kW of total photon power at planned SPEAR operating conditions. The first masks are located at 6.5 meters from the source and may receive a peak power density (transverse to the beam) exceeding 20 kW/cm 2 . Significantly, this heat transfer rate exceeds that radiated from the sun's surface (7 kW/cm 2 ) and is comparable to that of welding torches. Clearing, cooling and configuration are of critical importance. Configurations for the first fixed mask, the movable mask, and the pivot mask on this beam line are presented together with considerations of thermal stress fatigue and of heat transfer by conduction to water-cooling circuits. Some preliminary information on heating of crystals and mirrors is also presented

  12. Physics Teachers' Education (PTE): Problems and Challenges

    Science.gov (United States)

    Sassi, Elena; Michelini, Marisa

    A vast majority of the research results acknowledge the crucial role of teacher's education, as a vital tool in enhancing the quality of physics education. The projects like PISA, ROSE and TIMMS showcase the impact of teacher's education as a qualitative improvement in the physics learning environment. In Physics Education Research (PER), the impact of teacher's education had been addressed for the its role in the enhancement of positive interest among the students. The current world-wide state of the art characterizes a large variety of boundary conditions, traditions and practices that are being followed. In our present context, we foucus and discuss on the multidimensional challanges such as competencies needed, degrees required, problems encountered, support to be provided and the basic pre-requirements of Teacher's education for the secondary schools. We present some of the teaching methods and practices followed in coherent with, both, the Student centered and open learning environments along with some of the useful didactical indicators. Also, we potray a couple of research-based examples successfully experimented in Italy. Finally we propose some useful recommendations along with the criteria to be followed in the teachers education for the overall improvement.

  13. The vehicle routing problem latest advances and new challenges

    CERN Document Server

    Golden, Bruce L; Wasil, Edward A

    2008-01-01

    The Vehicle Routing Problem (VRP) has been an especially active and fertile area of research. Over the past five to seven years, there have been numerous technological advances and exciting challenges that are of considerable interest to students, teachers, and researchers. The Vehicle Routing Problem: Latest Advances and New Challenges will focus on a host of significant technical advances that have evolved over the past few years for modeling and solving vehicle routing problems and variants. New approaches for solving VRPs have been developed from important methodological advances. These developments have resulted in faster solution algorithms, more accurate techniques, and an improvement in the ability to solve large-scale, complex problems. The book will systematically examine these recent developments in the VRP and provide the following in a unified and carefully developed presentation: Present novel problems that have arisen in the vehicle routing domain and highlight new challenges for the field; Pre...

  14. Problems associated with accelerated thermal aging of electrical equipment

    International Nuclear Information System (INIS)

    Isgro, J.R.

    1984-01-01

    This paper discusses the potential problems that may be experienced when accounting for aging mechanisms in organic polymers when utilizing accelerated thermal aging techniques for electrical equipment qualification. Included are discussions of actual experiences and problems encountered in the qualification of electrical and electronic equipment for a complete nuclear power plant. The wide variety of approaches to thermal accelerated aging by various manufacturers of diverse equipment types provides depth to the discussion. A description of how to account for aging mechanisms is also presented

  15. Security surveillance challenges and proven thermal imaging capabilities in real-world applications

    Science.gov (United States)

    Francisco, Glen L.; Roberts, Sharon

    2004-09-01

    Uncooled thermal imaging was first introduced to the public in early 1980's by Raytheon (legacy Texas Instruments Defense Segment Electronics Group) as a solution for military applications. Since the introduction of this technology, Raytheon has remained the leader in this market as well as introduced commercial versions of thermal imaging products specifically designed for security, law enforcement, fire fighting, automotive and industrial uses. Today, low cost thermal imaging for commercial use in security applications is a reality. Organizations of all types have begun to understand the advantages of using thermal imaging as a means to solve common surveillance problems where other popular technologies fall short. Thermal imaging has proven to be a successful solution for common security needs such as: ¸ vision at night where lighting is undesired and 24x7 surveillance is needed ¸ surveillance over waterways, lakes and ports where water and lighting options are impractical ¸ surveillance through challenging weather conditions where other technologies will be challenged by atmospheric particulates ¸ low maintenance requirements due to remote or difficult locations ¸ low cost over life of product Thermal imaging is now a common addition to the integrated security package. Companies are relying on thermal imaging for specific applications where no other technology can perform.

  16. Transient thermal stress problem for a circumferentially cracked hollow cylinder

    Science.gov (United States)

    Nied, H. F.; Erdogan, F.

    1982-01-01

    The transient thermal stress problem for a hollow elasticity cylinder containing an internal circumferential edge crack is considered. It is assumed that the problem is axisymmetric with regard to the crack geometry and the loading, and that the inertia effects are negligible. The problem is solved for a cylinder which is suddenly cooled from inside. First the transient temperature and stress distributions in an uncracked cylinder are calculated. By using the equal and opposite of this thermal stress as the crack surface traction in the isothermal cylinder the crack problem is then solved and the stress intensity factor is calculated. The numerical results are obtained as a function of the Fourier number tD/b(2) representing the time for various inner-to-outer radius ratios and relative crack depths, where D and b are respectively the coefficient of diffusivity and the outer radius of the cylinder.

  17. Crowd Sourcing for Challenging Technical Problems and Business Model

    Science.gov (United States)

    Davis, Jeffrey R.; Richard, Elizabeth

    2011-01-01

    Crowd sourcing may be defined as the act of outsourcing tasks that are traditionally performed by an employee or contractor to an undefined, generally large group of people or community (a crowd) in the form of an open call. The open call may be issued by an organization wishing to find a solution to a particular problem or complete a task, or by an open innovation service provider on behalf of that organization. In 2008, the Space Life Sciences Directorate (SLSD), with the support of Wyle Integrated Science and Engineering, established and implemented pilot projects in open innovation (crowd sourcing) to determine if these new internet-based platforms could indeed find solutions to difficult technical challenges. These unsolved technical problems were converted to problem statements, also called "Challenges" or "Technical Needs" by the various open innovation service providers, and were then posted externally to seek solutions. In addition, an open call was issued internally to NASA employees Agency wide (10 Field Centers and NASA HQ) using an open innovation service provider crowd sourcing platform to post NASA challenges from each Center for the others to propose solutions). From 2008 to 2010, the SLSD issued 34 challenges, 14 externally and 20 internally. The 14 external problems or challenges were posted through three different vendors: InnoCentive, Yet2.com and TopCoder. The 20 internal challenges were conducted using the InnoCentive crowd sourcing platform designed for internal use by an organization. This platform was customized for NASA use and promoted as NASA@Work. The results were significant. Of the seven InnoCentive external challenges, two full and five partial awards were made in complex technical areas such as predicting solar flares and long-duration food packaging. Similarly, the TopCoder challenge yielded an optimization algorithm for designing a lunar medical kit. The Yet2.com challenges yielded many new industry and academic contacts in bone

  18. Capacity Building for School Development: Current Problems and Future Challenges

    Science.gov (United States)

    Ho, Dora; Lee, Moosung

    2016-01-01

    This article offers a theoretical discussion on the current problems and future challenges of school capacity building in early childhood education (ECE), aiming to highlight some key areas for future research. In recent years, there has been a notable policy shift from monitoring quality through inspection to improving quality through school…

  19. Tennessee Eastman Plant-wide Industrial Process Challenge Problem

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Cameron, Ian; Gani, Rafiqul

    2011-01-01

    This chapter presents a comprehensive analysis and modelling of the Tennessee Eastman challenge problem. Both a simplified model of the system as well as a full process model that includes the energy balances is given. In each case a full model analysis is carried out to establish the degrees...

  20. Vibration problems in nuclear power plants - challenges and opportunities

    International Nuclear Information System (INIS)

    Kakodkar, A.; Moorthy, R.I.K.

    1993-01-01

    Through specific examples like the Dhruva fuel vibration problems, it is shown that in different stages of a plant construction and operation that the vibration problems provide many challenging opportunities for innovative solutions to be applied. These examples also show that in-depth understanding of the dynamics of structures and equipment and general engineering skill could be used profitably to solve the different vibration problems and also to use the vibration signals effectively to monitor the health of the equipment and structures. Considering the safety and economic implications it can be concluded that the scope for application of these techniques is rather limitless. (author). 7 refs., 10 figs

  1. Contributions to thermal and fluid dynamic problems in nuclear technology

    International Nuclear Information System (INIS)

    Mueller, U.; Krebs, L.; Rust, K.

    1984-02-01

    The majority of contributions compiled in this report deals with thermal and fluid dynamic problems in nuclear engineering. Especially problems of heat transfer and cooling are represented which may arise during and afer a loss-of-coolant accident both in light water reactors and in liquid metal cooled fast breeder reactors. Papers on the mass transfer in pressurized water, tribological problems in sodium cooled reactors, the fluid dynamics of pulsed column, and fundamental investigations of convective flows supplement these contributions on problems connected with accidents. Furthermore, a keynote paper presents the individual activities relating to the reliability of reactor components, a field recently included in our research program. Technical solutions to special problems are closely connected to the investigations based on experiments. Therefore, several contributions deal with new developments in technology and measuring techniques. (orig.) [de

  2. Alternative solution algorithm for coupled thermal-hydraulic problems

    International Nuclear Information System (INIS)

    Farnsworth, D.A.; Rice, J.G.

    1986-01-01

    A thermal-hydraulic system involves flow of a fluid for which a combined solution of the continuity, momentum, and energy equations is required. When the solutions of the energy and momentum fields are dependent on each other, the system is said to be thermally coupled. A common problem encountered in the numerical solution of strongly coupled thermal-hydraulic problems is a very slow rate of convergence or a complete lack of convergence. Many times this degradation in convergence is due to the lack of true coupling between the energy and momentum fields during the iteration process. In the most widely used solution algorithms - such as the SIMPLE algorithm and its many variants - a sequential solution technique is required. That is, the solution process alternates between the flow and energy fields until a converged solution is obtained. This approach allows only implicit energy-momentum coupling. To improve the convergence rate for strongly coupled problems, a practical solution algorithm that can accommodate true energy-momentum coupling terms was developed. A complete simultaneous (versus sequential) solution of the governing conservation equations utilizing a line-by-line solution was developed and direct coupling terms between the momentum and energy fields were added utilizing a modified Newton-Raphson technique

  3. An Open Challenge Problem Repository for Systems Supporting Binders

    OpenAIRE

    Felty, A.; Momigliano, A.; Pientka, B.

    2015-01-01

    A variety of logical frameworks support the use of higher-order abstract syntax in representing formal systems; however, each system has its own set of benchmarks. Even worse, general proof assistants that provide special libraries for dealing with binders offer a very limited evaluation of such libraries, and the examples given often do not exercise and stress-test key aspects that arise in the presence of binders. In this paper we design an open repository ORBI (Open challenge problem Repo...

  4. IMPSOR, 3-D Boundary Problems Solution for Thermal Conductivity Calculation

    International Nuclear Information System (INIS)

    Wilson, D.G.; Williams, M.A.

    1994-01-01

    1 - Description of program or function: IMPSOR implements finite difference methods for multidimensional moving boundary problems with Dirichlet or Neumann boundary conditions. The geometry of the spatial domain is a rectangular parallelepiped with dimensions specified by the user. Dirichlet or Neumann boundary conditions may be specified on each face of the box independently. The user defines the initial and boundary conditions as well as the thermal and physical properties of the problem and several parameters for the numerical method, e.g. degree of implicitness, time-step size. 2 - Method of solution: The spatial domain is partitioned and the governing equation discretized, which yields a nonlinear system of equations at each time-step. This nonlinear system is solved using a successive over-relaxation (SOR) algorithm. For a given node, the previous iteration's temperature and thermal conductivity values are used for advanced points with current values at previous points. This constitutes a Gauss-Seidel iteration. Most of the computing time used by the numerical method is spent in the iterative solution of the nonlinear system. The SOR scheme employed is designed to accommodate vectorization on a Cray X-MP. 3 - Restrictions on the complexity of the problem: Maximum of 70,000 nodes

  5. Mitigating Drive-By Download Attacks: Challenges and Open Problems

    Science.gov (United States)

    Egele, Manuel; Kirda, Engin; Kruegel, Christopher

    Malicious web sites perform drive-by download attacks to infect their visitors with malware. Current protection approaches rely on black- or white-listing techniques that are difficult to keep up-to-date. As todays drive-by attacks already employ encryption to evade network level detection we propose a series of techniques that can be implemented in web browsers to protect the user from such threats. In addition, we discuss challenges and open problems that these mechanisms face in order to be effective and efficient.

  6. Numerical treatment of the unsteady hydromagnetic thermal boundary layer problem

    International Nuclear Information System (INIS)

    Drymonitou, M.A.; Geroyannis, V.S.; Goudas, C.L.

    1980-01-01

    This paper presents a suitable numerical method for the treatment of the unsteady hydromagnetic thermal boundary layer problem for flows past an infinite porous flat plate, the motion of which is governed by a general time-dependent law, under the influence of a transverse externally set magnetic field. The normal velocity of suction/injection at the plate is also assumed to be time-dependent. The results obtained on the basis of numerical approximations seem to compare favourably with earlier results (Pande et al., 1976; Tokis, 1978). Analytical approximations are given for the cases of a plate (i) generally accelerated and (ii) harmonically oscillating. The direct numerical treatment is obviously advantageous since it allows handling of cases where the known methods for analytical approximations are not applicable. This problem is closely related to the motions and heat transfer occurring locally on the surfaces of stars. (orig.)

  7. Splines employment for inverse problem of nonstationary thermal conduction

    International Nuclear Information System (INIS)

    Nikonov, S.P.; Spolitak, S.I.

    1985-01-01

    An analytical solution has been obtained for an inverse problem of nonstationary thermal conduction which is faced in nonstationary heat transfer data processing when the rewetting in channels with uniform annular fuel element imitators is investigated. In solving the problem both boundary conditions and power density within the imitator are regularized via cubic splines constructed with the use of Reinsch algorithm. The solution can be applied for calculation of temperature distribution in the imitator and the heat flux in two-dimensional approximation (r-z geometry) under the condition that the rewetting front velocity is known, and in one-dimensional r-approximation in cases with negligible axial transport or when there is a lack of data about the temperature disturbance source velocity along the channel

  8. Efficiency of management of sustainable development – challenges, problems, barriers

    Directory of Open Access Journals (Sweden)

    Zięba K.

    2016-06-01

    Full Text Available This paper discusses such issues as the importance of efficiency management of sustainable development. In the authors’ opinion, this matter is currently topical subject due to, among others, on the still high costs of irrational management in the field. Dynamically changing environment forces to search for new solutions for efficiency management of sustainable development, and unfortunately, in many countries it is still a significant problem. For some countries, the efficiency management of sustainable development is difficult. It should be noted that the problem with the inaction of relevant activities of the countries in the field of development of efficiency management of sustainability development will grow, because globalization makes it necessary to generate new solutions emerging to date problems. Facing each country there are so many challenges in the field. However, some countries are aware of the seriousness of the problem and therefore take a number of measures in this regard, often regardless of the amount of costs. This has an impact on their competitiveness. Apparent is also increasing incorporation of new original solutions in the field of sustainable development management.

  9. Reentry challenges facing women with mental health problems.

    Science.gov (United States)

    Visher, Christy A; Bakken, Nicholas W

    2014-01-01

    Women entering the correctional system represent a population at high risk for mental health and the body of research on the mental health needs of women offenders is growing. These mental health problems pose challenges for women at every stage of the criminal justice process, from arrest to incarceration to community reentry and reintegration. In this article, we examined mental health status among a sample of 142 women leaving confinement and the role that mental health problems played in shaping their reentry outcomes using data collected between 2002 and 2005 in Houston, Texas. In the year after leaving prison, women with mental health problems reported poorer health, more hospitalizations, more suicidal thoughts, greater difficulties securing housing and employment, more involvement in criminal behavior, and less financial support from family than women with no indication of mental health problems. However, mental health status did not increase the likelihood of substance use relapse or reincarceration. The article concludes with a discussion of recommendations for improved policy and practice.

  10. Challenges in thermal and hydraulic analysis of ADS target systems

    International Nuclear Information System (INIS)

    Groetzbach, G.; Batta, A.; Lefhalm, C.-H.; Otic, I.

    2004-01-01

    The liquid metal cooled spallation targets of Accelerator Driven nuclear reactor Systems obey high thermal loads; in addition some flow and cooling conditions are of a prototypical character; in contrast the operating conditions for the engaged materials are narrow; thus, the target development requires a very careful analysis by experimental and numerical means. Especially the cooling of the steel window, which is heated by the proton beam, needs special care. Some of the main goals of the experimental and numerical analyses of the thermal dynamics of those systems are discusses. The prediction of locally detached flows and of flows with larger recirculation areas suffers from insufficient turbulence modeling; this has to be compensated by using prototypical model experiments, e.g. with water, to select the adequate models and numerical schemes. The well known problems with the Reynolds analogy in predicting the heat transfer in liquid metals requires always prototypic liquid metal experiments to select and adapt the turbulent heat flux models. The uncertainties in liquid metal experiments cannot be neglected; so it is necessary to perform CFD calculations and experiments always hand in hand and to develop improve turbulent heat flux models. One contribution to an improved 3 or 4-equation model is deduced from recent Direct Numerical Simulation (DNS) data. (author)

  11. Block recursive LU preconditioners for the thermally coupled incompressible inductionless MHD problem

    Science.gov (United States)

    Badia, Santiago; Martín, Alberto F.; Planas, Ramon

    2014-10-01

    The thermally coupled incompressible inductionless magnetohydrodynamics (MHD) problem models the flow of an electrically charged fluid under the influence of an external electromagnetic field with thermal coupling. This system of partial differential equations is strongly coupled and highly nonlinear for real cases of interest. Therefore, fully implicit time integration schemes are very desirable in order to capture the different physical scales of the problem at hand. However, solving the multiphysics linear systems of equations resulting from such algorithms is a very challenging task which requires efficient and scalable preconditioners. In this work, a new family of recursive block LU preconditioners is designed and tested for solving the thermally coupled inductionless MHD equations. These preconditioners are obtained after splitting the fully coupled matrix into one-physics problems for every variable (velocity, pressure, current density, electric potential and temperature) that can be optimally solved, e.g., using preconditioned domain decomposition algorithms. The main idea is to arrange the original matrix into an (arbitrary) 2 × 2 block matrix, and consider an LU preconditioner obtained by approximating the corresponding Schur complement. For every one of the diagonal blocks in the LU preconditioner, if it involves more than one type of unknowns, we proceed the same way in a recursive fashion. This approach is stated in an abstract way, and can be straightforwardly applied to other multiphysics problems. Further, we precisely explain a flexible and general software design for the code implementation of this type of preconditioners.

  12. Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Rob; Wang, Zhenwei; Jankovic, Jasna; Yick, Sing; Maric, Radenka; Ghosh, Dave [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Kesler, Olivera [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4 (Canada); Rose, Lars [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Materials Engineering, University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 (Canada)

    2007-07-10

    In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 {mu}m) and dense electrolyte layer. Fed with H{sub 2} as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm{sup -2} at 900 C and 430 mW cm{sup -2} at 800 C at a cell voltage of 0.7 V. (author)

  13. Describing function theory as applied to thermal and neutronic problems

    International Nuclear Information System (INIS)

    Nassersharif, B.

    1983-01-01

    Describing functions have traditionally been used to obtain the solutions of systems of ordinary differential equations. In this work the describing function concept has been extended to include nonlinear, distributed parameter partial differential equations. A three-stage solution algorithm is presented which can be applied to any nonlinear partial differential equation. Two generalized integral transforms were developed as the T-transform for the time domain and the B-transform for the spatial domain. The thermal diffusion describing function (TDDF) is developed for conduction of heat in solids and a general iterative solution along with convergence criteria is presented. The proposed solution method is used to solve the problem of heat transfer in nuclear fuel rods with annular fuel pellets. As a special instance the solid cylindrical fuel pellet is examined. A computer program is written which uses the describing function concept for computing fuel pin temperatures in the radial direction during reactor transients. The second problem investigated was the neutron diffusion equation which is intrinsically different from the first case. Although, for most situations, it can be treated as a linear differential equation, the describing function method is still applicable. A describing function solution is derived for two possible cases: constant diffusion coefficient and variable diffusion coefficient. Two classes of describing functions are defined for each case which portray the leakage and absorption phenomena. For the specific case of a slab reactor criticality problem the comparison between analytical and describing function solutions revealed an excellent agreement

  14. The carbon dioxide problem - a challenge to environmental protection

    International Nuclear Information System (INIS)

    Hlubek, W.; Spalthoff, F.J.

    1989-01-01

    Over the last century, man's activities on earth have sent off trace gases into the planet's atmosphere that have been concentrating to a level posing a threat to the global climate. Since scientists particularly spotted carbon dioxide as the main contributor to what we now call the greenhouse effect, there is urgent need for measures reducing carbon dioxide emission worldwide, may be on the basis of a global convention to be signed by both the industrialised and the developing countries. The industrialised countries, which certainly are the main pollutors, also will have the technological and financial resources to respond to the challenge of global warning more directly and faster than the developing countries. The power industry's management in the FRG is taking the problem seriously and has already come out with strategies for curbing carbon dioxide emissions from fossil-fuel power plant. (orig.) [de

  15. Eigenvalue solutions in finite element thermal transient problems

    International Nuclear Information System (INIS)

    Stoker, J.R.

    1975-01-01

    The eigenvalue economiser concept can be useful in solving large finite element transient heat flow problems in which the boundary heat transfer coefficients are constant. The usual economiser theory is equivalent to applying a unit thermal 'force' to each of a small sub-set of nodes on the finite element mesh, and then calculating sets of resulting steady state temperatures. Subsequently it is assumed that the required transient temperature distributions can be approximated by a linear combination of this comparatively small set of master temperatures. The accuracy of a reduced eigenvalue calculation depends upon a good choice of master nodes, which presupposes at least a little knowledge about what sort of shape is expected in the unknown temperature distributions. There are some instances, however, where a reasonably good idea exists of the required shapes, permitting a modification to the economiser process which leads to greater economy in the number of master temperatures. The suggested new approach is to use manually prescribed temperature distributions as the master distributions, rather than using temperatures resulting from unit thermal forces. Thus, with a little pre-knowledge one may write down a set of master distributions which, as a linear combination, can represent the required solution over the range of interest to a reasonable engineering accuracy, and using the minimum number of variables. The proposed modified eigenvalue economiser technique then uses the master distributions in an automatic way to arrive at the required solution. The technique is illustrated by some simple finite element examples

  16. Cooling problems of thermal power plants. Physical model studies

    International Nuclear Information System (INIS)

    Neale, L.C.

    1975-01-01

    The Alden Research Laboratories of Worcester Polytechnic Institute has for many years conducted physical model studies, which are normally classified as river or structural hydraulic studies. Since 1952 one aspect of these studies has involved the heated discharge from steam power plants. The early studies on such problems concentrated on improving the thermal efficiency of the system. This was accomplished by minimizing recirculation and by assuring full use of available cold water supplies. With the growing awareness of the impact of thermal power generation on the environment attention has been redirected to reducing the effect of heated discharges on the biology of the receiving body of water. More specifically the efforts of designers and operators of power plants are aimed at meeting or complying with standards established by various governmental agencies. Thus the studies involve developing means of minimizing surface temperatures at an outfall or establishing a local area of higher temperature with limits specified in terms of areas or distances. The physical models used for these studies have varied widely in scope, size, and operating features. These models have covered large areas with both distorted geometric scales and uniform dimensions. Instrumentations has also varied from simple mercury thermometers to computer control and processing of hundreds of thermocouple indicators

  17. Earth's Rotation: A Challenging Problem in Mathematics and Physics

    Science.gov (United States)

    Ferrándiz, José M.; Navarro, Juan F.; Escapa, Alberto; Getino, Juan

    2015-01-01

    A suitable knowledge of the orientation and motion of the Earth in space is a common need in various fields. That knowledge has been ever necessary to carry out astronomical observations, but with the advent of the space age, it became essential for making observations of satellites and predicting and determining their orbits, and for observing the Earth from space as well. Given the relevant role it plays in Space Geodesy, Earth rotation is considered as one of the three pillars of Geodesy, the other two being geometry and gravity. Besides, research on Earth rotation has fostered advances in many fields, such as Mathematics, Astronomy and Geophysics, for centuries. One remarkable feature of the problem is in the extreme requirements of accuracy that must be fulfilled in the near future, about a millimetre on the tangent plane to the planet surface, roughly speaking. That challenges all of the theories that have been devised and used to-date; the paper makes a short review of some of the most relevant methods, which can be envisaged as milestones in Earth rotation research, emphasizing the Hamiltonian approach developed by the authors. Some contemporary problems are presented, as well as the main lines of future research prospected by the International Astronomical Union/International Association of Geodesy Joint Working Group on Theory of Earth Rotation, created in 2013.

  18. Engineering Risk Assessment of Space Thruster Challenge Problem

    Science.gov (United States)

    Mathias, Donovan L.; Mattenberger, Christopher J.; Go, Susie

    2014-01-01

    The Engineering Risk Assessment (ERA) team at NASA Ames Research Center utilizes dynamic models with linked physics-of-failure analyses to produce quantitative risk assessments of space exploration missions. This paper applies the ERA approach to the baseline and extended versions of the PSAM Space Thruster Challenge Problem, which investigates mission risk for a deep space ion propulsion system with time-varying thruster requirements and operations schedules. The dynamic mission is modeled using a combination of discrete and continuous-time reliability elements within the commercially available GoldSim software. Loss-of-mission (LOM) probability results are generated via Monte Carlo sampling performed by the integrated model. Model convergence studies are presented to illustrate the sensitivity of integrated LOM results to the number of Monte Carlo trials. A deterministic risk model was also built for the three baseline and extended missions using the Ames Reliability Tool (ART), and results are compared to the simulation results to evaluate the relative importance of mission dynamics. The ART model did a reasonable job of matching the simulation models for the baseline case, while a hybrid approach using offline dynamic models was required for the extended missions. This study highlighted that state-of-the-art techniques can adequately adapt to a range of dynamic problems.

  19. 3-D thermal weight function method and multiple virtual crack extension technique for thermal shock problems

    International Nuclear Information System (INIS)

    Lu Yanlin; Zhou Xiao; Qu Jiadi; Dou Yikang; He Yinbiao

    2005-01-01

    An efficient scheme, 3-D thermal weight function (TWF) method, and a novel numerical technique, multiple virtual crack extension (MVCE) technique, were developed for determination of histories of transient stress intensity factor (SIF) distributions along 3-D crack fronts of a body subjected to thermal shock. The TWF is a universal function, which is dependent only on the crack configuration and body geometry. TWF is independent of time during thermal shock, so the whole history of transient SIF distributions along crack fronts can be directly calculated through integration of the products of TWF and transient temperatures and temperature gradients. The repeated determinations of the distributions of stresses (or displacements) fields for individual time instants are thus avoided in the TWF method. An expression of the basic equation for the 3-D universal weight function method for Mode I in an isotropic elastic body is derived. This equation can also be derived from Bueckner-Rice's 3-D WF formulations in the framework of transformation strain. It can be understood from this equation that the so-called thermal WF is in fact coincident with the mechanical WF except for some constants of elasticity. The details and formulations of the MVCE technique are given for elliptical cracks. The MVCE technique possesses several advantages. The specially selected linearly independent VCE modes can directly be used as shape functions for the interpolation of unknown SIFs. As a result, the coefficient matrix of the final system of equations in the MVCE method is a triple-diagonal matrix and the values of the coefficients on the main diagonal are large. The system of equations has good numerical properties. The number of linearly independent VCE modes that can be introduced in a problem is unlimited. Complex situations in which the SIFs vary dramatically along crack fronts can be numerically well simulated by the MVCE technique. An integrated system of programs for solving the

  20. Municipal solid waste management in China: status, problems and challenges.

    Science.gov (United States)

    Zhang, Dong Qing; Tan, Soon Keat; Gersberg, Richard M

    2010-08-01

    This paper presents an examination of MSW generation and composition in China, providing an overview of the current state of MSW management, an analysis of existing problems in MSW collection, separation, recycling and disposal, and some suggestions for improving MSW systems in the future. In China, along with urbanization, population growth and industrialization, the quantity of municipal solid waste (MSW) generation has been increasing rapidly. The total MSW amount increased from 31.3 million tonnes in 1980 to 212 million tonnes in 2006, and the waste generation rate increased from 0.50 kg/capita/day in 1980 to 0.98 kg/capita/year in 2006. Currently, waste composition in China is dominated by a high organic and moisture content, since the concentration of kitchen waste in urban solid waste makes up the highest proportion (at approximately 60%) of the waste stream. The total amount of MSW collected and transported was 148 million tonnes in 2006, of which 91.4% was landfilled, 6.4% was incinerated and 2.2% was composted. The overall MSW treatment rate in China was approximately 62% in 2007. In 2007, there were 460 facilities, including 366 landfill sites, 17 composing plants, and 66 incineration plants. This paper also considers the challenges faced and opportunities for MSW management in China, and a number of recommendations are made aimed at improving the MSW management system. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Managing Radioactive Waste. Problems and Challenges in a Globalizing World

    Energy Technology Data Exchange (ETDEWEB)

    2010-09-15

    Many countries are at a crossroads in terms of maintaining their energy supply. The existing resources of fossil fuels are dwindling, and global warming makes their use increasingly problematic. Nuclear power is now often regarded inevitable for future sustainability, energy security, and economic prosperity. There are, however, still unsolved problems regarding nuclear power. The fact that no country has established a final waste repository for spent nuclear fuel throws fundamental doubt on nuclear energy expansion. Also, the processes of globalization have transformed the nuclear industry towards increased privatization, concentration, and internationalization. This leads to uncertainties regarding the responsibility for nuclear waste management. In these circumstances is it of greatest importance that scholars from different disciplines, as well as policy makers and practitioners within the field, meet to share experiences. This conference had the general objective of producing knowledge about the challenges caused by global developmental trends, and what the management of nuclear waste implies for contemporary and future social development. Over 100 persons attended the conferences. Papers available at the conference site have been separately indexed. Several contributions were also made as PP-presentation, which are available at the site, among others the Keynote Speeches: Waiting for the Nuclear Renaissance: Exploring the Nexus of Expansion and Disposal in Europe (Jane Dawson); Applying the Risk Governance Framework: Institutional Requirements for Dealing with Nuclear Waste (Ortwin Renn); Learning to Listen: The Long Road to Legitimating Radioactive Waste Management Policies (Frans Berkhout); The Nuclear Waste Debate is Irrational but We Need Not Panic (Frank von Hippel). The conference was divided into the following sessions: Session A: Political characteristics matters; Session B: Radioactivity, geology, society. On a problem definition of HLW

  2. Managing Radioactive Waste. Problems and Challenges in a Globalizing World

    International Nuclear Information System (INIS)

    2010-09-01

    Many countries are at a crossroads in terms of maintaining their energy supply. The existing resources of fossil fuels are dwindling, and global warming makes their use increasingly problematic. Nuclear power is now often regarded inevitable for future sustainability, energy security, and economic prosperity. There are, however, still unsolved problems regarding nuclear power. The fact that no country has established a final waste repository for spent nuclear fuel throws fundamental doubt on nuclear energy expansion. Also, the processes of globalization have transformed the nuclear industry towards increased privatization, concentration, and internationalization. This leads to uncertainties regarding the responsibility for nuclear waste management. In these circumstances is it of greatest importance that scholars from different disciplines, as well as policy makers and practitioners within the field, meet to share experiences. This conference had the general objective of producing knowledge about the challenges caused by global developmental trends, and what the management of nuclear waste implies for contemporary and future social development. Over 100 persons attended the conferences. Papers available at the conference site have been separately indexed. Several contributions were also made as PP-presentation, which are available at the site, among others the Keynote Speeches: Waiting for the Nuclear Renaissance: Exploring the Nexus of Expansion and Disposal in Europe (Jane Dawson); Applying the Risk Governance Framework: Institutional Requirements for Dealing with Nuclear Waste (Ortwin Renn); Learning to Listen: The Long Road to Legitimating Radioactive Waste Management Policies (Frans Berkhout); The Nuclear Waste Debate is Irrational but We Need Not Panic (Frank von Hippel). The conference was divided into the following sessions: Session A: Political characteristics matters; Session B: Radioactivity, geology, society. On a problem definition of HLW

  3. Plasma experiments elucidative for challenging problems investigated in other branches of science

    International Nuclear Information System (INIS)

    Sanduloviciu, M.; Popescu, S.

    2001-01-01

    Driving away from thermal equilibrium a plasma initially in an asymptotic stable state it is possible to identify the succession of the physical processes that form, as a whole, a new scenario of self-organization able to explain, besides the challenging problems of non-equilibrium physics, also some of the today not solved essential problems of the chemical and biological sciences. Thus, plasma experiments have revealed the presence of a local self-enhancement mechanism associated with long-range inhibition that explains pattern formation in general. Two successively produced instabilities originated in a positive feedback mechanism were identified to be at the origin of the spatial and spatial-temporal patterns, respectively. This feedback mechanism comprises a self-enhancing mechanism of the production of positive ions complemented by the creation of a net negative space charge by accumulation of electrons that have lost their kinetic energy in neutral excitations. The informational content concerning self-organization revealed by the plasma experiments suggests the presence of a new physical basis for the behavior of the systems working as differential negative resistance, but also new information on the actual cause of the anomalous transport of particles and energy. These results present special interest in solid state physics where the mechanism of current instabilities observed in semiconductors is today a non-conclusively solved problem. Anomalous transport of particles and energy is today a challenging problem of high energy physics because it is considered as the principal cause that impedes the improvement of the economical performances of fusion devices. Since all chemical and biological phenomena involve, at least, physical processes, the scenario of self-organization identified in plasma could be elucidative for understanding the phenomena, as for instance, the pattern formation in chemical media, but also the spontaneous self-assembling of the

  4. Problems, Challenges and Prospects of Female Entrepreneurs in ...

    African Journals Online (AJOL)

    This paper seeks to discuss female entrepreneurs and the challenges they ... to make meaningful contributions to their family, the area council and the nation. ... in enabling the women to start their own business, types of businesses women ...

  5. Solving the problems of thermal effects and outputs

    International Nuclear Information System (INIS)

    Jaske, R.T.

    1974-01-01

    All energy used ultimately appears in the environment as a thermal release, this paper points out, and many of the measures taken to reduce other types of pollutants ultimately increase thermal pollution because energy is required to operate the pollution control equipment. A number of measures that may be taken to reduce the ratio of net energy use to gross national product are pointed out

  6. NASTRAN thermal analyzer: Theory and application including a guide to modeling engineering problems, volume 2. [sample problem library guide

    Science.gov (United States)

    Jackson, C. E., Jr.

    1977-01-01

    A sample problem library containing 20 problems covering most facets of Nastran Thermal Analyzer modeling is presented. Areas discussed include radiative interchange, arbitrary nonlinear loads, transient temperature and steady-state structural plots, temperature-dependent conductivities, simulated multi-layer insulation, and constraint techniques. The use of the major control options and important DMAP alters is demonstrated.

  7. Children with chronic continence problems: the challenges for families.

    Science.gov (United States)

    Erickson, David V; Ray, Lynne D

    2004-01-01

    For families who are raising children with myelomeningocele, bowel and bladder incontinence presents unique challenges for everyday life. The Parenting and Childhood Chronicity model is used to describe the work of raising a child with a chronic condition in 6 areas, including medical care, adapted parenting, dealing with the systems, caring for siblings, maintaining relationships, and personal coping (keeping yourself going). This article provides an overview of the physiologic and developmental challenges inherent in this neural tube defect and illustrates the work that is involved in the child's care and the challenges of maintaining a balance in family life. Clinical implications are discussed, including the setting of appropriate expectations, providing parents with accurate information, ensuring that a focus on continence is not at the expense of other important aspects of the child's functioning, and supporting parents in their interaction with the school system. The medical team, consisting of nursing, urology, nephrology, and psychology working together, can be a strong support for families.

  8. TECHNOLOGICAL AND ENVIRONMENTAL PROBLEMS CONNECTED WITH THERMAL CONVERSION OF SEWAGE SLUDGE

    Directory of Open Access Journals (Sweden)

    Alina Żogała

    2016-02-01

    Full Text Available Overview of the most common technological and environmental problems connected with thermal conversion of sewage sludge was presented in the article. Such issues as the influence of content of moisture and mineral matter on fuel properties of sludge, problem of emission of pollutants, problem of management of solid residue, risk of corrosion, were described. Besides, consolidated characteristic of the most important methods of thermal conversion of sewage sludge, with their advantages and disadvantages, was presented in the paper.

  9. Pre-service teachers’ challenges in presenting mathematical problems

    Science.gov (United States)

    Desfitri, R.

    2018-01-01

    The purpose of this study was to analyzed how pre-service teachers prepare and assigned tasks or assignments in teaching practice situations. This study was also intended to discuss about kind of tasks or assignments they gave to students. Participants of this study were 15 selected pre-service mathematics teachers from mathematics education department who took part on microteaching class as part of teaching preparation program. Based on data obtained, it was occasionally found that there were hidden errors on questions or tasks assigned by pre-service teachers which might lead their students not to be able to reach a logical or correct answer. Although some answers might seem to be true, they were illogical or unfavourable. It is strongly recommended that pre-service teachers be more careful when posing mathematical problems so that students do not misunderstand the problems or the concepts, since both teachers and students were sometimes unaware of errors in problems being worked on.

  10. Prospects for solving environmental problems pertinent to thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Tumanovskii; V.R. Kotler [OAO All-Russia Thermal Engineering Institute, Moscow (Russian Federation)

    2007-06-15

    Possible ways to protect the atmosphere and water basin against harmful emissions and effluent waters discharged from thermal power stations are considered. Data on the effectiveness of different methods for removing NOx, SO{sub 2}, and ash particles, as well as heavy metals and CO{sub 2}, from these emissions and discharges are presented.

  11. Problems, challenges and promises: perspectives on precision medicine.

    Science.gov (United States)

    Duffy, David J

    2016-05-01

    The 'precision medicine (systems medicine)' concept promises to achieve a shift to future healthcare systems with a more proactive and predictive approach to medicine, where the emphasis is on disease prevention rather than the treatment of symptoms. The individualization of treatment for each patient will be at the centre of this approach, with all of a patient's medical data being computationally integrated and accessible. Precision medicine is being rapidly embraced by biomedical researchers, pioneering clinicians and scientific funding programmes in both the European Union (EU) and USA. Precision medicine is a key component of both Horizon 2020 (the EU Framework Programme for Research and Innovation) and the White House's Precision Medicine Initiative. Precision medicine promises to revolutionize patient care and treatment decisions. However, the participants in precision medicine are faced with a considerable central challenge. Greater volumes of data from a wider variety of sources are being generated and analysed than ever before; yet, this heterogeneous information must be integrated and incorporated into personalized predictive models, the output of which must be intelligible to non-computationally trained clinicians. Drawing primarily from the field of 'oncology', this article will introduce key concepts and challenges of precision medicine and some of the approaches currently being implemented to overcome these challenges. Finally, this article also covers the criticisms of precision medicine overpromising on its potential to transform patient care. © The Author 2015. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  12. Sleep medicine in Saudi Arabia: Current problems and future challenges

    Science.gov (United States)

    BaHammam, Ahmed S.

    2011-01-01

    Sleep medicine is a relatively new specialty in the medical community. The practice of sleep medicine in Saudi Arabia (KSA) began in the mid to late nineties. Since its inception, the specialty has grown, and the number of specialists has increased. Nevertheless, sleep medicine is still underdeveloped in the KSA, particularly in the areas of clinical service, education, training and research. Based on available data, it appears that sleep disorders are prevalent among Saudis, and the demand for sleep medicine service is expected to rise significantly in the near future. A number of obstacles have been defined that hinder the progress of the specialty, including a lack of trained technicians, specialists and funding. Awareness about sleep disorders and their serious consequences is low among health care workers, health care authorities, insurance companies and the general public. A major challenge for the future is penetrating the educational system at all levels to demonstrate the high prevalence and serious consequences of sleep disorders. To attain adequate numbers of staff and facilities, the education and training of health care professionals at the level of sleep medicine specialists and sleep technologists is another important challenge that faces the specialty. This review discusses the current position of sleep medicine as a specialty in the KSA and the expected challenges of the future. In addition, it will guide clinicians interested in setting up new sleep medicine services in the KSA or other developing countries through the potential obstacles that may face them in this endeavor. PMID:21264164

  13. Sleep medicine in Saudi Arabia: Current problems and future challenges

    Directory of Open Access Journals (Sweden)

    BaHammam Ahmed

    2011-01-01

    Full Text Available Sleep medicine is a relatively new specialty in the medical community. The practice of sleep medicine in Saudi Arabia (KSA began in the mid to late nineties. Since its inception, the specialty has grown, and the number of specialists has increased. Nevertheless, sleep medicine is still underdeveloped in the KSA, particularly in the areas of clinical service, education, training and research. Based on available data, it appears that sleep disorders are prevalent among Saudis, and the demand for sleep medicine service is expected to rise significantly in the near future. A number of obstacles have been defined that hinder the progress of the specialty, including a lack of trained technicians, specialists and funding. Awareness about sleep disorders and their serious consequences is low among health care workers, health care authorities, insurance companies and the general public. A major challenge for the future is penetrating the educational system at all levels to demonstrate the high prevalence and serious consequences of sleep disorders. To attain adequate numbers of staff and facilities, the education and training of health care professionals at the level of sleep medicine specialists and sleep technologists is another important challenge that faces the specialty. This review discusses the current position of sleep medicine as a specialty in the KSA and the expected challenges of the future. In addition, it will guide clinicians interested in setting up new sleep medicine services in the KSA or other developing countries through the potential obstacles that may face them in this endeavor.

  14. Challenges of Environmental Problems to the Philosophy of Education

    Science.gov (United States)

    Kato, Moricmichi

    2015-01-01

    We live in an age in which the destruction of the environment has become a major concern. However, until recently, environmental problems have not become a major issue for the philosophy of education. The reason for this is that for a very long time the philosophy of education was intimately related to the concept of nature as the foundation and…

  15. Psychological Problems and Challenge In EFL Speaking Classroom

    Directory of Open Access Journals (Sweden)

    Win Listyaningrum Arifin

    2017-07-01

    Full Text Available Psychological aspect regarding to learning attitudes plays in determining learning achievement. Psychological problems also involve not only to the students but also teacher. Less-confidence, speech anxiety, and low self-esteem are almost common problem in classroom, and occur on both teachers and students. Students who have low of self-confidence are often hardly able to control themselves for public speaking in the classroom, like, Governing his/ her behavior on that his/her peers think, lose belief on self, thinking that his/her friends dis-appraising, afraid of getting mistakes, etc. However, teachers which are low self-esteem and confidence also lose their performance and ability to manage their classroom optimally. Low self-esteem may caused by teacher’s poor understanding on subject matter. Both of psychological problems impact on dis-effectiveness of classroom activities. This paper takes accounts of some psychological problems of students and teachers in English speaking classroom, and some guidelines to overcome. At the last discus, this paper also provides some keys of how to make good classroom atmosphere.

  16. Thermal shock problems of bonded structure for plasma facing components

    International Nuclear Information System (INIS)

    Shibui, M.; Kuroda, T.; Kubota, Y.

    1991-01-01

    Thermal shock tests have been performed on W(Re)/Cu and Mo/Cu duplex structures with a particular emphasis on two failure modes: failure on the heated surface and failure near the bonding interface. The results indicate that failure of the duplex structure largely depends on the constraint of thermal strain on the heated surface and on the ductility changes of armour materials. Rapid debonding of the bonding interface may be attributed to the yielding of armour materials. This leads to a residual bending deformation when the armour cools down. Arguments are also presented in this paper on two parameter characterization of the failure of armour materials and on stress distribution near the free edge of the bonding interface. (orig.)

  17. Transmutor demo unit and thermal into electrical energy transformation problems

    International Nuclear Information System (INIS)

    Matal, O.; Fiedler, J.

    1999-01-01

    In the three circuits layout of the transmutor the heat is transferred from the primary through the secondary circuits by a favourable heat carrier into the tertiary circuit where the thermal into electrical energy transformation in turbo-generator comes into force. Properties as well as parameters of the heat carrier in the secondary circuit affect basically both the conceptual layout of the tertiary circuit and consequently investments costs for its realization and the effectiveness of the transformation of thermal into electrical energy. For several heat carriers considered for the transmutor secondary circuit particular tertiary circuit concepts for the demonstration transmutor unit of approx. 15 W thermal power rate are analyzed, layout features and possibilities of turbogenerator selection are commented and investment costs as well as effectiveness of thermal into electrical energy transformation are estimated. Some of the results are as follows: (i) Heat carrier properties influence thermodynamics of the TDU water/steam cycle substantially. One of the dominant parameters is the melting (freezing) temperature of the heat carrier. (ii) Heat carrier properties influence investment costs of components of the TDU tertiary circuit substantially. Dominantly influenced are costs of the steam generator, steam turbine and high pressure regeneration system. (iii) If the heat carrier has to be a molten salt than a salt with a low melting temperature is recommended to be selected, for example KHF2. (iv) Eutectic alloy Pb-Bi as the heat carrier serves changes to design the TDU with efficient thermodynamics, with acceptable low investment costs of the tertiary as well as secondary circuit components and with an acceptable level of the nuclear safety

  18. Wicked Problems in Large Organizations: Why Pilot Retention Continues to Challenge the Air Force

    Science.gov (United States)

    2017-05-25

    solving complex problems even more challenging.10 This idea of complexity extends to another theoretical concept , the complex adaptive system, which... concept in order to avoid the pitfalls and dangers in group problem - solving .26 His ideas to mitigate potential groupthink place responsibility... Problems in Large Organizations: Why Pilot Retention Continues to Challenge the Air Force 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  19. Profile of men's health in Malaysia: problems and challenges

    Science.gov (United States)

    Tong, Seng Fah; Low, Wah Yun; Ng, Chirk Jenn

    2011-01-01

    Men's health concerns have evolved from the traditional andrology and male sexual health to a more holistic approach that encompasses male psychological, social and physical health. The poor state of health in men compared to their female counterparts is well documented. A review of the epidemiological data from Malaysia noted a similar trend in which men die at higher rates in under 1 and above 15 years old groups and most disease categories compared to women. In Malaysia, the main causes of death in men are non-communicable diseases and injuries. Risk factors, such as risk-taking behaviour, smoking and hypertension, are prevalent and amenable to early interventions. Erectile dysfunction, premature ejaculation and prostate disorders are also prevalent. However, many of these morbidities go unreported and are not diagnosed early; therefore, opportunities for early intervention are missed. This reflects poor health knowledge and inadequate health-care utilisation among Malaysian men. Their health-seeking behaviour has been shown to be strongly influenced by family members and friends. However, more research is needed to identify men's unmet health-care needs and to develop optimal strategies for addressing them. Because the Malaysian population is aging and there is an increase in sedentary lifestyles, optimizing men's health will remain a challenge unless effective measures are implemented. The existing male-unfriendly health-care system and the negative influence of masculinity on men's health behaviour must be addressed. A national men's health policy based on a male-friendly approach to health-care delivery is urgently needed to provide a framework for addressing these challenges. PMID:21358664

  20. Profile of men's health in Malaysia: problems and challenges.

    Science.gov (United States)

    Tong, Seng Fah; Low, Wah Yun; Ng, Chirk Jenn

    2011-07-01

    Men's health concerns have evolved from the traditional andrology and male sexual health to a more holistic approach that encompasses male psychological, social and physical health. The poor state of health in men compared to their female counterparts is well documented. A review of the epidemiological data from Malaysia noted a similar trend in which men die at higher rates in under 1 and above 15 years old groups and most disease categories compared to women. In Malaysia, the main causes of death in men are non-communicable diseases and injuries. Risk factors, such as risk-taking behaviour, smoking and hypertension, are prevalent and amenable to early interventions. Erectile dysfunction, premature ejaculation and prostate disorders are also prevalent. However, many of these morbidities go unreported and are not diagnosed early; therefore, opportunities for early intervention are missed. This reflects poor health knowledge and inadequate health-care utilisation among Malaysian men. Their health-seeking behaviour has been shown to be strongly influenced by family members and friends. However, more research is needed to identify men's unmet health-care needs and to develop optimal strategies for addressing them. Because the Malaysian population is aging and there is an increase in sedentary lifestyles, optimizing men's health will remain a challenge unless effective measures are implemented. The existing male-unfriendly health-care system and the negative influence of masculinity on men's health behaviour must be addressed. A national men's health policy based on a male-friendly approach to health-care delivery is urgently needed to provide a framework for addressing these challenges.

  1. Analysis result for OECD benchmark on thermal fatigue problem

    International Nuclear Information System (INIS)

    Kamaya, Masayuki; Nakamura, Akira; Fujii, Yuzou

    2005-01-01

    The main objective of this analysis is to understand the crack growth behavior under three-dimensional (3D) thermal fatigue by conducting 3D crack initiation and propagation analyses. The possibility of crack propagation through the wall thickness of pipe, and the accuracy of the prediction of crack initiation and propagation are of major interest. In this report, in order to estimate the heat transfer coefficients and evaluate the thermal stress, conventional finite element analysis (FEA) is conducted. Then, the crack driving force is evaluated by using the finite element alternating method (FEAM), which can derive the stress intensity factor (SIF) under 3D mechanical loading based on finite element analysis without generating the mesh for a cracked body. Through these two realistic 3D numerical analyses, it has been tried to predict the crack initiation and propagation behavior. The thermal fatigue crack initiation and propagation behavior were numerically analyzed. The conventional FEA was conducted in order to estimate the heat transfer coefficient and evaluate the thermal stress. Then, the FEAM was conducted to evaluate the SIFs of surface single cracks and interacting multiple cracks, and crack growth was evaluated. The results are summarized as follows: 1. The heat transfer coefficients were estimated as H air = 40 W/m 2 K and H water = 5000 W/m 2 K. This allows simulation of the change in temperature with time at the crack initiation points obtained by the experiment. 2. The maximum stress occurred along the line of symmetry and the maximum Mises equivalent stress was 572 MPa. 3. By taking the effect of mean stress into account according to the modified Goodman diagram, the equivalent stress range and the number of cycles to crack initiation were estimated as 1093 MPa and 3.8x10 4 , respectively, although the tensile strength was assumed to be 600 MPa. 4. It was shown from the evaluated SIFs that longitudinal cracks can penetrate the wall of the pipe

  2. Thermal hydraulic issues and challenges for current and new generation FBRs

    Energy Technology Data Exchange (ETDEWEB)

    Chellapandi, P.; Velusamy, K., E-mail: kvelu@igcar.gov.in

    2015-12-01

    Highlights: • We present challenges in thermal hydraulic design of sodium cooled fast reactors. • We present roadmap of Indian fast reactor program and innovative design concepts. • Analysis methodology for thermal striping and thermal stratification are highlighted. • Design solutions for gas entrainment are presented. • Experimental approaches for normal and post accident decay heat removal are highlighted. - Abstract: Pool type sodium cooled fast reactors pose several design challenges and among them, certain thermal hydraulics and structural mechanics issues are special. High frequency temperature fluctuations due to thermal striping, thermal stratifications and sodium free level fluctuations at the liquid–cover gas interfaces are to be investigated carefully to eliminate high cycle thermal fatigue of structures. Solutions to address the core thermal hydraulics call for high power computing. Innovative concepts and methods are developed to carry out plant dynamics and safety studies. Particularly, extensive numerical and experimental simulation techniques are needed for understanding and solving the gas entrainment mechanisms and its effects on core safety. Though decay heat removal through natural convection is achievable in a pool type SFR, demonstration of design solutions conceived in the reactor and performance of diverse systems under all operating conditions, especially over prolonged station blackout situations needs advanced CFD computations and should be validated by relatively large scale simulated experiments. These issues are addressed in this paper under five broad topics: special thermal hydraulic issues to be addressed in SFR, thermal hydraulic design and analysis, plant dynamics studies, safety studies and evolving thermal hydraulic studies for the future FBRs. The 500 MWe Prototype Fast Breeder Reactor (PFBR) is taken as the reference design for addressing the issues. Indian fast reactor programme is highlighted in the introduction

  3. The single-collision thermalization approximation for application to cold neutron moderation problems

    International Nuclear Information System (INIS)

    Ritenour, R.L.

    1989-01-01

    The single collision thermalization (SCT) approximation models the thermalization process by assuming that neutrons attain a thermalized distribution with only a single collision within the moderating material, independent of the neutron's incident energy. The physical intuition on which this approximation is based is that the salient properties of neutron thermalization are accounted for in the first collision, and the effects of subsequent collisions tend to average out statistically. The independence of the neutron incident and outscattering energy leads to variable separability in the scattering kernel and, thus, significant simplification of the neutron thermalization problem. The approximation also addresses detailed balance and neutron conservation concerns. All of the tests performed on the SCT approximation yielded excellent results. The significance of the SCT approximation is that it greatly simplifies thermalization calculations for CNS design. Preliminary investigations with cases involving strong absorbers also indicates that this approximation may have broader applicability, as in the upgrading of the thermalization codes

  4. Challenge problem and milestones for : Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC).

    Energy Technology Data Exchange (ETDEWEB)

    Freeze, Geoffrey A.; Wang, Yifeng; Howard, Robert; McNeish, Jerry A.; Schultz, Peter Andrew; Arguello, Jose Guadalupe, Jr.

    2010-09-01

    This report describes the specification of a challenge problem and associated challenge milestones for the Waste Integrated Performance and Safety Codes (IPSC) supporting the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The NEAMS challenge problems are designed to demonstrate proof of concept and progress towards IPSC goals. The goal of the Waste IPSC is to develop an integrated suite of modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. To demonstrate proof of concept and progress towards these goals and requirements, a Waste IPSC challenge problem is specified that includes coupled thermal-hydrologic-chemical-mechanical (THCM) processes that describe (1) the degradation of a borosilicate glass waste form and the corresponding mobilization of radionuclides (i.e., the processes that produce the radionuclide source term), (2) the associated near-field physical and chemical environment for waste emplacement within a salt formation, and (3) radionuclide transport in the near field (i.e., through the engineered components - waste form, waste package, and backfill - and the immediately adjacent salt). The initial details of a set of challenge milestones that collectively comprise the full challenge problem are also specified.

  5. Challenge problem and milestones for: Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC)

    International Nuclear Information System (INIS)

    Freeze, Geoffrey A.; Wang, Yifeng; Howard, Robert; McNeish, Jerry A.; Schultz, Peter Andrew; Arguello, Jose Guadalupe Jr.

    2010-01-01

    This report describes the specification of a challenge problem and associated challenge milestones for the Waste Integrated Performance and Safety Codes (IPSC) supporting the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The NEAMS challenge problems are designed to demonstrate proof of concept and progress towards IPSC goals. The goal of the Waste IPSC is to develop an integrated suite of modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. To demonstrate proof of concept and progress towards these goals and requirements, a Waste IPSC challenge problem is specified that includes coupled thermal-hydrologic-chemical-mechanical (THCM) processes that describe (1) the degradation of a borosilicate glass waste form and the corresponding mobilization of radionuclides (i.e., the processes that produce the radionuclide source term), (2) the associated near-field physical and chemical environment for waste emplacement within a salt formation, and (3) radionuclide transport in the near field (i.e., through the engineered components - waste form, waste package, and backfill - and the immediately adjacent salt). The initial details of a set of challenge milestones that collectively comprise the full challenge problem are also specified.

  6. HEATING6 analysis of international thermal benchmark problem sets 1 and 2

    International Nuclear Information System (INIS)

    Childs, K.W.; Bryan, C.B.

    1986-10-01

    In order to assess the heat transfer computer codes used in the analysis of nuclear fuel shipping casks, the Nuclear Energy Agency Committee on Reactor Physics has defined seven problems for benchmarking thermal codes. All seven of these problems have been solved using the HEATING6 heat transfer code. This report presents the results of five of the problems. The remaining two problems were used in a previous benchmarking of thermal codes used in the United States, and their solutions have been previously published

  7. Nanomaterials in consumer products: a challenging analytical problem

    Directory of Open Access Journals (Sweden)

    Catia eContado

    2015-08-01

    Full Text Available Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs, generally added to improve the product quality. To evaluate correctly benefits versus risks of engineered nanomaterials and consequently to legislate in favor of consumer’s protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences.On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization.This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors.The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.

  8. Nanomaterials in consumer products: a challenging analytical problem.

    Science.gov (United States)

    Contado, Catia

    2015-01-01

    Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.

  9. An inverse heat transfer problem for optimization of the thermal ...

    Indian Academy of Sciences (India)

    Department of Production Engineering, Faculty of Technical Science, ... ductivity of manufacturing and high levels of machining quality and accuracy, are the most ... inverse problems are today successfully applied in identification, design, control and optimiza- ...... of Machine Tools and Manufacture, 35(5): 751–760.

  10. Problem trap final repository. Social challenges concerning nuclear waste

    International Nuclear Information System (INIS)

    Brunnengraeber, Achim

    2016-01-01

    How is it possible that there is still no final storage facility in the entire world for highly radioactive waste from nuclear power stations? How is it possible that electricity has been generated by industrial-scale nuclear installations for decades without the issue of the disposal of nuclear waste having been resolved? The events in Chernobyl in 1986 and Fukushima in 2011 have made it blatantly obvious how risky this technology is and how important it is to keep humans and the environment at a safe distance from radioactivity. This anthology examines the technological, political, social and economic dimensions of the permanent disposal of nuclear waste. It provides an insight into the emergence of the problem and the people involved and their interests. It describes and analyses the changes that are taking place in Germany (for instance, in relation to the government's commission on nuclear repositories) and other countries with regard to how they handle nuclear waste. The book deals with both questions related to socio-technical aspects of the permanent disposal of nuclear waste and calls for the democratic need for participation and new ways of doing so, without which the search for a permanent disposal site will not bear fruit. This anthology presents a comprehensive discussion of the disposal of nuclear waste and the search for a permanent repository for it. Not only will students and teachers find it extremely useful, but so will any readers who are interested in its subject matter and wish to gain a more in-depth insight into it.

  11. On the thermal raleigh problem in partially ionized argon

    International Nuclear Information System (INIS)

    Hutten Mansfeld, A.C.B.

    1976-01-01

    A partially ionized gas is created by the reflection of a shock wave with incident Mach numbers in the range 7 to 10 and an initial pressure of 5 Torr against the cold end wall of a shock tube. Heat exchange between the plasma and this cold wall induces several relaxation processes in the thermal boundary layer. Of these, relaxation of i) the electron and heavy particles temperature and ii) the degree of ionization towards a local thermodynamic equilibrium state are considered. In the model, transport and relaxation processes are treated simultaneously. A classification on the basis of relaxation phenomena is performed, i.e., simplified sets of equations are obtained in a systematic way from the frozen or equilibrium limits of the relaxation processes. A finite difference numerical solution for the different models is obtained. Because the boundary conditions are of mixed type and the relaxation processes show aspects of stiffness, the application of a backward implicit discretization scheme is necessary. As a diagnostic tool, a two wavelength version of the laser schlieren method is used. The measurements provide time histories of both the electron and atom number density gradients

  12. The Problem Behaviour Check List: a short scale to assess challenging behaviours

    OpenAIRE

    Tyrer, PJ; Nagar, J; Evans, R; Oliver, P; Bassett, P; Liedtka, N; Tarabi, A

    2016-01-01

    Background Challenging behaviour, especially in intellectual disability, covers a wide range that is in need of further evaluation. Aims To develop a short but comprehensive instrument for all aspects of challenging behaviour. Method In the first part of a two-stage enquiry, a 28-item scale was constructed to examine the components of challenging behaviour. Following a simple factor analysis this was developed further to create a new short scale, the Problem Behaviour Checklist (PBCL). The sc...

  13. Myth 15: High-Ability Students Don't Face Problems and Challenges

    Science.gov (United States)

    Moon, Sidney M.

    2009-01-01

    One rationale for failure to address the needs of high-ability students in schools is that high-ability students do not need special services because they do not face any special problems or challenges. A more extreme corollary of this attitude is the notion that high ability is so protective that students with high ability do not face problems or…

  14. Problem solving as a challenge for mathematics education in The Netherlands

    NARCIS (Netherlands)

    Doorman, M.; Drijvers, P.; Dekker, T.; Heuvel-Panhuizen, T. van; Lange, J. de; Wijers, M.

    2007-01-01

    This paper deals with the challenge to establish problem solving as a living domain in mathematics education in The Netherlands. While serious attempts are made to implement a problem-oriented curriculum based on principles of realistic mathematics education with room for modelling and with

  15. Promoting Collaborative Problem-Solving Skills in a Course on Engineering Grand Challenges

    Science.gov (United States)

    Zou, Tracy X. P.; Mickleborough, Neil C.

    2015-01-01

    The ability to solve problems with people of diverse backgrounds is essential for engineering graduates. A course on engineering grand challenges was designed to promote collaborative problem-solving (CPS) skills. One unique component is that students need to work both within their own team and collaborate with the other team to tackle engineering…

  16. Estimation of the thermal properties in alloys as an inverse problem

    International Nuclear Information System (INIS)

    Zueco, J.; Alhama, F.

    2005-01-01

    This paper provides an efficient numerical method for estimating the thermal conductivity and heat capacity of alloys, as a function of the temperature, starting from temperature measurements (including errors) in heating and cooling processes. The proposed procedure is a modification of the known function estimation technique, typical of the inverse problem field, in conjunction with the network simulation method (already checked in many non-lineal problems) as the numerical tool. Estimations only require a point of measurement. The methodology is applied for determining these thermal properties in alloys within ranges of temperature where allotropic changes take place. These changes are characterized by sharp temperature dependencies. (Author) 13 refs

  17. Determination of the thermal conductivity and specific heat capacity of neem seeds by inverse problem method

    Directory of Open Access Journals (Sweden)

    S.N. Nnamchi

    2010-01-01

    Full Text Available Determination of the thermal conductivity and the specific heat capacity of neem seeds (Azadirachta indica A. Juss usingthe inverse method is the main subject of this work. One-dimensional formulation of heat conduction problem in a spherewas used. Finite difference method was adopted for the solution of the heat conduction problem. The thermal conductivityand the specific heat capacity were determined by least square method in conjunction with Levenberg-Marquardt algorithm.The results obtained compare favourably with those obtained experimentally. These results are useful in the analysis ofneem seeds drying and leaching processes.

  18. From centralized hydro-thermal to decentralized renewable : the Austrian challenge

    International Nuclear Information System (INIS)

    Brauner, G.

    2007-01-01

    Austria's electricity production scheme is currently based on 67 per cent hydro power, 25 per cent fossil thermal power and 8 per cent new renewable energy, including wind, biomass, and photovoltaic conversion. As demand on centralized energy systems increases, the power generation, transmission and distribution system in the country will have to be restructured to increase the portion of regenerative generation. Decentralized micro-grid structures are a promising concept for meeting the target of efficiency improvement and renewable generation because they make it possible to use regenerative energy where it is collected. The most efficient way to meet the challenges of efficiency improvement and emission reduction is the replacement of old coal-fired power stations by new combined-cycle gas power stations with combined heat and power. This will reduce both carbon dioxide emissions as well as specific fossil energy demand. However, in just 1 decade the emission reduction achieved by fuel switching and higher efficiency of power stations will be equalized by higher demand, which is growing at an annual rate of 2 per cent. Future energy problems will be characterized by the security of supply; climatic change and the need for clean energy technologies; the lack of transmission-routes; and growing energy demand. The regenerative energy in Austria currently consists of hydraulic large run-of-river hydraulic generation as well as small scale hydro and large scale hydro storage systems. Biomass currently has a total generating capacity of 280 MW and forms 3.14 per cent of generation in Austria. Wind has reached a capacity of 950 MW and forms 3.8 per cent of generation in Austria. It was concluded that the future philosophy in energy supply will not be to try to increase regenerative generation according to growing demand, but to improve end-use efficiency and reduce demand according to the renewable regional potential. 4 refs., 4 figs

  19. Application of the SHARP Toolkit to Sodium-Cooled Fast Reactor Challenge Problems

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Yu, Y. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2017-09-30

    The Simulation-based High-efficiency Advanced Reactor Prototyping (SHARP) toolkit is under development by the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign of the U.S. Department of Energy, Office of Nuclear Energy. To better understand and exploit the benefits of advanced modeling simulations, the NEAMS Campaign initiated the “Sodium-Cooled Fast Reactor (SFR) Challenge Problems” task, which include the assessment of hot channel factors (HCFs) and the demonstration of zooming capability using the SHARP toolkit. If both challenge problems are resolved through advanced modeling and simulation using the SHARP toolkit, the economic competitiveness of a SFR can be significantly improved. The efforts in the first year of this project focused on the development of computational models, meshes, and coupling procedures for multi-physics calculations using the neutronics (PROTEUS) and thermal-hydraulic (Nek5000) components of the SHARP toolkit, as well as demonstration of the HCF calculation capability for the 100 MWe Advanced Fast Reactor (AFR-100) design. Testing the feasibility of the SHARP zooming capability is planned in FY 2018. The HCFs developed for the earlier SFRs (FFTF, CRBR, and EBR-II) were reviewed, and a subset of these were identified as potential candidates for reduction or elimination through high-fidelity simulations. A one-way offline coupling method was used to evaluate the HCFs where the neutronics solver PROTEUS computes the power profile based on an assumed temperature, and the computational fluid dynamics solver Nek5000 evaluates the peak temperatures using the neutronics power profile. If the initial temperature profile used in the neutronics calculation is reasonably accurate, the one-way offline method is valid because the neutronics power profile has weak dependence on small temperature variation. In order to get more precise results, the proper temperature profile for initial neutronics calculations was obtained from the

  20. Characteristic thermal-hydraulic problems in NHRs: Overview of experimental investigations and computer codes

    Energy Technology Data Exchange (ETDEWEB)

    Falikov, A A; Vakhrushev, V V; Kuul, V S; Samoilov, O B; Tarasov, G I [OKBM, Nizhny Novgorod (Russian Federation)

    1997-09-01

    The paper briefly reviews the specific thermal-hydraulic problems for AST-type NHRs, the experimental investigations that have been carried out in the RF, and the design procedures and computer codes used for AST-500 thermohydraulic characteristics and safety validation. (author). 13 refs, 10 figs, 1 tab.

  1. Grand challenge problems in environmental modeling and remediation: Groundwater contaminant transport. Final project report 1998

    International Nuclear Information System (INIS)

    1998-04-01

    The over-reaching goal of the Groundwater Grand Challenge component of the Partnership in Computational Science (PICS) was to develop and establish the massively parallel approach for the description of groundwater flow and transport and to address the problem of uncertainties in the data and its interpretation. This necessitated the development of innovative algorithms and the implementation of massively parallel computational tools to provide a suite of simulators for groundwater flow and transport in heterogeneous media. This report summarizes the activities and deliverables of the Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1997

  2. Benefits and Challenges when Performing Robust Topology Optimization for Interior Acoustic Problems

    DEFF Research Database (Denmark)

    Christiansen, Rasmus Ellebæk; Jensen, Jakob Søndergaard; Lazarov, Boyan Stefanov

    The objective of this work is to present benets and challenges of using robust topology optimization techniques for minimizing the sound pressure in interior acoustic problems. The focus is on creating designs which maintain high performance under uniform spatial variations. This work takes offset...... in previous work considering topology optimization for interior acoustic problems, [1]. However in the previous work the robustness of the designs was not considered....

  3. Benefits and Challenges when Performing Robust Topology Optimization for Interior Acoustic Problems

    OpenAIRE

    Christiansen, Rasmus Ellebæk; Jensen, Jakob Søndergaard; Lazarov, Boyan Stefanov; Sigmund, Ole

    2014-01-01

    The objective of this work is to present benets and challenges of using robust topology optimization techniques for minimizing the sound pressure in interior acoustic problems. The focus is on creating designs which maintain high performance under uniform spatial variations. This work takes offset in previous work considering topology optimization for interior acoustic problems, [1]. However in the previous work the robustness of the designs was not considered.

  4. Fourth-Grade Primary School Students' Thought Processes and Challenges Encountered during the Butter Beans Problem

    Science.gov (United States)

    Sahin, Neslihan; Eraslan, Ali

    2017-01-01

    In parallel with mathematical modeling studies that have gradually drawn interest in recent years, the aim of this study is to investigate the thought processes of fourth-grade students in the Butter Beans Problem and to identify possible challenges in this process. For this purpose, a qualitative study was conducted at a university-foundation…

  5. The COSMO solution to the SWS challenge mediation problem scenarios: an evaluation

    NARCIS (Netherlands)

    Asuncion, C.H.; van Sinderen, Marten J.; Quartel, Dick; Blake, Brian; Cabral, Liliana; Köning-Ries, Birgitta; Küster, Ulrich; Martin, David

    2012-01-01

    During the course of our participation in the Semantic Web Services (SWS) Challenge, we have shown how the concepts defined in the COnceptual Services MOdeling (COSMO) framework for the modeling, reasoning and analysis of services can be used to solve the Mediation Problem Scenarios of the

  6. Grand challenge problems in environmental modeling and remediation: groundwater contaminant transport

    Energy Technology Data Exchange (ETDEWEB)

    Todd Arbogast; Steve Bryant; Clint N. Dawson; Mary F. Wheeler

    1998-08-31

    This report describes briefly the work of the Center for Subsurface Modeling (CSM) of the University of Texas at Austin (and Rice University prior to September 1995) on the Partnership in Computational Sciences Consortium (PICS) project entitled Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport.

  7. A scope of the problem: Post-deployment reintegration challenges in a National Guard Unit.

    Science.gov (United States)

    Wilcox, Sherrie L; Oh, Hyunsung; Redmond, Sarah A; Chicas, Joseph; Hassan, Anthony M; Lee, Pey-Jiuan; Ell, Kathleen

    2015-01-01

    More Reserve and Guard members have been activated in the past few years than in any other time in history. In addition to the high rates of psychological and behavioral challenges among military personnel, there are other equally important post-deployment reintegration challenges. Post-deployment reintegration challenges are particularly important to Reserve and Guard members, who transition rapidly from civilian-military-civilian. This study aims to describe the scope of challenges that a battalion of National Guard members (NGM) report experiencing after returning from a one-year deployment to Iraq. This article reports data from a sample of 126 NGM who recently returned from a one-year deployment to Iraq. The scope of post-deployment problems at baseline, 3- and 6-month post-deployment are presented. Overall, the rates of post-deployment psychological and behavioral problems were elevated upon returning from deployment and remained fairly constant for up to 6 months post-deployment. Approximately 30% of respondents were unsatisfied with their relationship and upwards of 30% reported family reintegration challenges. Comparisons with similar research and implications for prevention and improvement of post-deployment quality of life are addressed.

  8. Numerical solution of problems concerning the thermal convection of a variable-viscosity liquid

    Science.gov (United States)

    Zherebiatev, I. F.; Lukianov, A. T.; Podkopaev, Iu. L.

    A stabilizing-correction scheme is constructed for integrating the fourth-order equation describing the dynamics of a viscous incompressible liquid. As an example, a solution is obtained to the problem of the solidification of a liquid in a rectangular region with allowance for convective energy transfer in the liquid phase as well as temperature-dependent changes of viscosity. It is noted that the proposed method can be used to study steady-state problems of thermal convection in ingots obtained through continuous casting.

  9. ANISOTROPIC THERMAL CONDUCTION AND THE COOLING FLOW PROBLEM IN GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Parrish, Ian J.; Sharma, Prateek; Quataert, Eliot

    2009-01-01

    We examine the long-standing cooling flow problem in galaxy clusters with three-dimensional magnetohydrodynamics simulations of isolated clusters including radiative cooling and anisotropic thermal conduction along magnetic field lines. The central regions of the intracluster medium (ICM) can have cooling timescales of ∼200 Myr or shorter-in order to prevent a cooling catastrophe the ICM must be heated by some mechanism such as active galactic nucleus feedback or thermal conduction from the thermal reservoir at large radii. The cores of galaxy clusters are linearly unstable to the heat-flux-driven buoyancy instability (HBI), which significantly changes the thermodynamics of the cluster core. The HBI is a convective, buoyancy-driven instability that rearranges the magnetic field to be preferentially perpendicular to the temperature gradient. For a wide range of parameters, our simulations demonstrate that in the presence of the HBI, the effective radial thermal conductivity is reduced to ∼<10% of the full Spitzer conductivity. With this suppression of conductive heating, the cooling catastrophe occurs on a timescale comparable to the central cooling time of the cluster. Thermal conduction alone is thus unlikely to stabilize clusters with low central entropies and short central cooling timescales. High central entropy clusters have sufficiently long cooling times that conduction can help stave off the cooling catastrophe for cosmologically interesting timescales.

  10. Problems and challenges in relation to the treatment of patients with multimorbidity

    DEFF Research Database (Denmark)

    Søndergaard, Elisabeth; Willadsen, Tora Grauers; Guassora, Ann Dorrit

    2015-01-01

    Objective. To explore views and attitudes among general practitioners (GPs) and researchers in the field of general practice towards problems and challenges related to treatment of patients with multimorbidity. Setting. A workshop entitled Patients with multimorbidity in general practice held...... during the Nordic Congress of General Practice in Tampere, Finland, 2013. Subjects. A total of 180 GPs and researchers. Design. Data for this summary report originate from audio-recorded, transcribed verbatim plenary discussions as well as 76 short questionnaires answered by attendees during the workshop...... of multimorbid patients underlined the GPs’ impression of a fragmented health care system; (iii) GPs found it challenging to establish a good dialogue and prioritize problems with patients within the timeframe of a normal consultation; (iv) the future role of the GP was discussed in relation to diminishing...

  11. Technological Solutions to Social and Citizen Problems. The Case of Civic and Public Challenges in Mexico

    Directory of Open Access Journals (Sweden)

    Martin Adalberto TENA-ESPINOZA-DE-LOS-MONTEROS

    2017-04-01

    Full Text Available This paper describes the process of civic innovation that, based on technological solutions and open initiatives, the civic society’s organization Codeando México suggests for the attention and solution of social and civic problems in Mexico. The Retos Cívicos (Civic Challenges and Retos Públicos (Public Challenges initiatives are addressed and described as experiences of innovation in the implementation of technological strategies for the solution of social and civic problems. A reflection is made on the civic appropriation of the ICTs and its irruption in the processes of innovation, as well as on the impact that the ICTs have in the conformation of a new civic ecosystem. Last, the strategies of Hacking cívico (Civic Hacking and Comunidades Cívicas (Civic Communities that the Codeando México organization promotes as a model for the linkage and civic participation within the frame of civic innovation, are mentioned.

  12. Response of turkey muscle satellite cells to thermal challenge. I. transcriptome effects in proliferating cells.

    Science.gov (United States)

    Reed, Kent M; Mendoza, Kristelle M; Abrahante, Juan E; Barnes, Natalie E; Velleman, Sandra G; Strasburg, Gale M

    2017-05-06

    Climate change poses a multi-dimensional threat to food and agricultural systems as a result of increased risk to animal growth, development, health, and food product quality. This study was designed to characterize transcriptional changes induced in turkey muscle satellite cells cultured under cold or hot thermal challenge to better define molecular mechanisms by which thermal stress alters breast muscle ultrastructure. Satellite cells isolated from the pectoralis major muscle of 7-weeks-old male turkeys from two breeding lines (16 weeks body weight-selected and it's randombred control) were proliferated in culture at 33 °C, 38 °C or 43 °C for 72 h. Total RNA was isolated and 12 libraries subjected to RNAseq analysis. Statistically significant differences in gene expression were observed among treatments and between turkey lines with a greater number of genes altered by cold treatment than by hot and fewer differences observed between lines than between temperatures. Pathway analysis found that cold treatment resulted in an overrepresentation of genes involved in cell signaling/signal transduction and cell communication/cell signaling as compared to control (38 °C). Heat-treated muscle satellite cells showed greater tendency towards expression of genes related to muscle system development and differentiation. This study demonstrates significant transcriptome effects on turkey skeletal muscle satellite cells exposed to thermal challenge. Additional effects on gene expression could be attributed to genetic selection for 16 weeks body weight (muscle mass). New targets are identified for further research on the differential control of satellite cell proliferation in poultry.

  13. Contribution to the study of thermal-hydraulic problems in nuclear reactors

    International Nuclear Information System (INIS)

    Cognet, G.

    1998-01-01

    In nuclear reactors, whatever the type considered, Pressurized Water Water Reactors (PWRs), Fast Breeder reactors (FBRs)..., thermal-hydraulics, the science of fluid mechanics and thermal behaviour, plays an essential role, both in nominal operating and accidental conditions. Fluid can either be the primary fluid (liquid or gas) or a very specific fluid called corium, which, in case of severe accident, could result from core and environning structure melting. The work reported here represents a 20-year contribution to thermal-hydraulic issues which could occur in FBRs and PWRs. Working on these two types of reactors, both in nominal and severe accident situations, has allowed me to compare the problems and to realize the importance of communication between research teams. The evolution in the complexity of studied problems, unavoidable in order to reduce costs and significantly improve safety, has led me from numerical modelling of single-phase flow turbulence to high temperature real melt experiments. The difficulties encountered in understanding the observed phenomena and in increasing experimental databases for computer code qualification have often entailed my participation in specific measurement device developments or adaptations, in particular non-intrusive devices generally based on optical techniques. Being concerned about the end-use of this research work, I actively participated in 'in-situ' thermalhydraulic experiments in the FBRs: Phenix and Super-Phenix, of which I appreciated their undeniable scientific contribution. In my opinion, the thermal-hydraulic questions related to severe accidents are the most complex as they are at the cross-roads of several scientific specialities. Consequently, they require a multi-disciplinary approach and a continuous see-saw motion between experimentalists and modelling teams. After a brief description of the various problems encountered, the main ones are reported. Finally, the importance for research teams to

  14. Multidimensional inverse heat conduction problem: optimization of sensor locations and utilization of thermal-strain measurements

    International Nuclear Information System (INIS)

    Blanc, Gilles

    1996-01-01

    This work is devoted to the solution of the inverse multidimensional heat conduction problem. The first part is the determination of a methodology for determining the minimum number of sensors and the best sensor locations. The method is applied to a 20 problem but the extension to 30 problems is quite obvious. This methodology is based on the study of the rate of representation. This new concept allows to determine the quantity and the quality of the information obtain from the various sensors. The rate of representation is a useful tool for experimental design. lt can be determined very quickly by the transposed matrix method. This approach was validated with an experimental set-up. The second part is the development of a method that uses thermal strain measurement instead of temperature measurements to estimate the unknown thermal boundary conditions. We showed that this new sensor has two advantages in comparison with the classical temperature measurements: higher frequency can be estimated and smaller number of sensors can be used for 20 problems. The main weakness is, presently, the fact that the method can only be applied to beams. The results obtained from the numerical simulations were validated by the analysis of experimental data obtained on an experimental set-up especially designed and built for this study. (author) [fr

  15. An efficient chaos embedded hybrid approach for hydro-thermal unit commitment problem

    International Nuclear Information System (INIS)

    Yuan, Xiaohui; Ji, Bin; Yuan, Yanbin; Ikram, Rana M.; Zhang, Xiaopan; Huang, Yuehua

    2015-01-01

    Highlights: • Thermal unit commitment is considered in hydrothermal generation scheduling (SHTGS). • Two newly proposed promising optimization algorithms are combined to solving SHTGS. • The proposed method is enhanced by integrating a chaotic local search strategy. • Heuristic search strategies are applied to handle the constraints of the SHTGS. • The results verify the proposed method is feasible and efficient for handling SHTGS. - Abstract: This paper establishes a model to deal with the short-term hydrothermal generation scheduling (SHTGS) problem. The problem is composed of three interconnected parts: short-term hydrothermal coordination, thermal unit commitment and economic load dispatch. An efficient hybrid method composed of chaotic backtracking search optimization algorithm and binary charged system search algorithm (CBSA–BCSS) is proposed to solve this problem. In order to analyze the effect of the chaotic map on the performance of the method, three different chaotic maps are adopted to integrate into the proposed method and the corresponding consequences are achieved. Furthermore, efficient heuristic search strategies are adopted to handle with the complicated constraints of the SHTGS system. Finally, a hydrothermal unit commitment system is utilized to verify the feasibility and effectiveness of the proposed method. The results demonstrate the efficiency of the hybrid optimization method and the appropriation of the constraint handling strategies. The comparison of the solutions achieved by different methods shows that the proposed method has higher efficiency in terms of solving SHTGS problem

  16. Some computational challenges of developing efficient parallel algorithms for data-dependent computations in thermal-hydraulics supercomputer applications

    International Nuclear Information System (INIS)

    Woodruff, S.B.

    1994-01-01

    The Transient Reactor Analysis Code (TRAC), which features a two-fluid treatment of thermal-hydraulics, is designed to model transients in water reactors and related facilities. One of the major computational costs associated with TRAC and similar codes is calculating constitutive coefficients. Although the formulations for these coefficients are local, the costs are flow-regime- or data-dependent; i.e., the computations needed for a given spatial node often vary widely as a function of time. Consequently, a fixed, uniform assignment of nodes to prallel processors will result in degraded computational efficiency due to the poor load balancing. A standard method for treating data-dependent models on vector architectures has been to use gather operations (or indirect adressing) to sort the nodes into subsets that (temporarily) share a common computational model. However, this method is not effective on distributed memory data parallel architectures, where indirect adressing involves expensive communication overhead. Another serious problem with this method involves software engineering challenges in the areas of maintainability and extensibility. For example, an implementation that was hand-tuned to achieve good computational efficiency would have to be rewritten whenever the decision tree governing the sorting was modified. Using an example based on the calculation of the wall-to-liquid and wall-to-vapor heat-transfer coefficients for three nonboiling flow regimes, we describe how the use of the Fortran 90 WHERE construct and automatic inlining of functions can be used to ameliorate this problem while improving both efficiency and software engineering. Unfortunately, a general automatic solution to the load-balancing problem associated with data-dependent computations is not yet available for massively parallel architectures. We discuss why developers should either wait for such solutions or consider alternative numerical algorithms, such as a neural network

  17. ATHENA [Advanced Thermal Hydraulic Energy Network Analyzer] solutions to developmental assessment problems

    International Nuclear Information System (INIS)

    Carlson, K.E.; Ransom, V.H.; Roth, P.A.

    1987-03-01

    The ATHENA (Advanced Thermal Hydraulic Energy Network Analyzer) code has been developed to perform transient simulation of the thermal hydraulic systems that may be found in fusion reactors, space reactors, and other advanced systems. As an assessment of current capability the code was applied to a number of physical problems, both conceptual and actual experiments. Results indicate that the numerical solution to the basic conservation equations is technically sound, and that generally good agreement can be obtained when modeling relevant hydrodynamic experiments. The assessment also demonstrates basic fusion system modeling capability and verifies compatibility of the code with both CDC and CRAY mainframes. Areas where improvements could be made include constitutive modeling, which describes the interfacial exchange term. 13 refs., 84 figs

  18. Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens.

    Directory of Open Access Journals (Sweden)

    Stephanie LeBlanc

    Full Text Available With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15 using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5. Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch and would require more exaggerated correctional movements. We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask, with and without space limitations (obstacles and combinations thereof. Video recordings (600 Hz and a three-axis accelerometer/gyroscope (100 Hz were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both

  19. Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens.

    Science.gov (United States)

    LeBlanc, Stephanie; Tobalske, Bret; Quinton, Margaret; Springthorpe, Dwight; Szkotnicki, Bill; Wuerbel, Hanno; Harlander-Matauschek, Alexandra

    2016-01-01

    With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15) using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5). Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch) and would require more exaggerated correctional movements. We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask), with and without space limitations (obstacles) and combinations thereof. Video recordings (600 Hz) and a three-axis accelerometer/gyroscope (100 Hz) were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both health categories

  20. A method of solution of the elastic-plastic thermal stress problem

    International Nuclear Information System (INIS)

    Rafalski, P.

    1975-01-01

    The purpose of the work is an improvement of the numerical technique for calculating the thermal stress distribution in an elastic-plastic structural element. The work consists of two parts. In the first a new method of solution of the thermal stress problem for the elastic-plastic body is presented. In the second a particular numerical technique, based on the above method, for calculating the stress and strain fields is proposed. A new mathematical approach consists in treating the stress and strain fields as mathematical objects defined in the space-time domain. The methods commonly applied use the stress and strain fields defined in the space domain and establish the relations between them at a given instant t. They reduce the problem to the system of ordinary differential equations with respect to time, which are usually solved with a step-by-step technique. The new method reduces the problem to the system of nonlinear algebraic equations. In the work the Hilbert space of admissible tensor fields is constructed. This space is the orthogonal sum of two subspaces: of statically admissible and kinematically admissible fields. Two alternative orthogonality conditions, which correspond to the equilibrium and compatibility equations with the appropriate boundary conditions, are derived. The results of the work are to be used for construction of the computer program for calculation the stress and strain fields in the elastic-plastic body with a prescribed temperature field in the interior and appropriate displacement and force conditions on the boundary

  1. Endocannabinoid Catabolic Enzymes Play Differential Roles in Thermal Homeostasis in Response to Environmental or Immune Challenge.

    Science.gov (United States)

    Nass, Sara R; Long, Jonathan Z; Schlosburg, Joel E; Cravatt, Benjamin F; Lichtman, Aron H; Kinsey, Steven G

    2015-06-01

    Cannabinoid receptor agonists, such as Δ(9)-THC, the primary active constituent of Cannabis sativa, have anti-pyrogenic effects in a variety of assays. Recently, attention has turned to the endogenous cannabinoid system and how endocannabinoids, including 2-arachidonoylglycerol (2-AG) and anandamide, regulate multiple homeostatic processes, including thermoregulation. Inhibiting endocannabinoid catabolic enzymes, monoacylglycerol lipase (MAGL) or fatty acid amide hydrolase (FAAH), elevates levels of 2-AG or anandamide in vivo, respectively. The purpose of this experiment was to test the hypothesis that endocannabinoid catabolic enzymes function to maintain thermal homeostasis in response to hypothermic challenge. In separate experiments, male C57BL/6J mice were administered a MAGL or FAAH inhibitor, and then challenged with the bacterial endotoxin lipopolysaccharide (LPS; 2 mg/kg ip) or a cold (4 °C) ambient environment. Systemic LPS administration caused a significant decrease in core body temperature after 6 h, and this hypothermia persisted for at least 12 h. Similarly, cold environment induced mild hypothermia that resolved within 30 min. JZL184 exacerbated hypothermia induced by either LPS or cold challenge, both of which effects were blocked by rimonabant, but not SR144528, indicating a CB1 cannabinoid receptor mechanism of action. In contrast, the FAAH inhibitor, PF-3845, had no effect on either LPS-induced or cold-induced hypothermia. These data indicate that unlike direct acting cannabinoid receptor agonists, which elicit profound hypothermic responses on their own, neither MAGL nor FAAH inhibitors affect normal body temperature. However, these endocannabinoid catabolic enzymes play distinct roles in thermoregulation following hypothermic challenges.

  2. Metaheuristic Algorithms Applied to Bioenergy Supply Chain Problems: Theory, Review, Challenges, and Future

    Directory of Open Access Journals (Sweden)

    Krystel K. Castillo-Villar

    2014-11-01

    Full Text Available Bioenergy is a new source of energy that accounts for a substantial portion of the renewable energy production in many countries. The production of bioenergy is expected to increase due to its unique advantages, such as no harmful emissions and abundance. Supply-related problems are the main obstacles precluding the increase of use of biomass (which is bulky and has low energy density to produce bioenergy. To overcome this challenge, large-scale optimization models are needed to be solved to enable decision makers to plan, design, and manage bioenergy supply chains. Therefore, the use of effective optimization approaches is of great importance. The traditional mathematical methods (such as linear, integer, and mixed-integer programming frequently fail to find optimal solutions for non-convex and/or large-scale models whereas metaheuristics are efficient approaches for finding near-optimal solutions that use less computational resources. This paper presents a comprehensive review by studying and analyzing the application of metaheuristics to solve bioenergy supply chain models as well as the exclusive challenges of the mathematical problems applied in the bioenergy supply chain field. The reviewed metaheuristics include: (1 population approaches, such as ant colony optimization (ACO, the genetic algorithm (GA, particle swarm optimization (PSO, and bee colony algorithm (BCA; and (2 trajectory approaches, such as the tabu search (TS and simulated annealing (SA. Based on the outcomes of this literature review, the integrated design and planning of bioenergy supply chains problem has been solved primarily by implementing the GA. The production process optimization was addressed primarily by using both the GA and PSO. The supply chain network design problem was treated by utilizing the GA and ACO. The truck and task scheduling problem was solved using the SA and the TS, where the trajectory-based methods proved to outperform the population

  3. Medicines counterfeiting is a complex problem: a review of key challenges across the supply chain.

    Science.gov (United States)

    Tremblay, Michael

    2013-02-01

    The paper begins by asking why there is a market for counterfeit medicines, which in effect creates the problem of counterfeiting itself. Contributing factors include supply chain complexity and the lack of whole-systems thinking. These two underpin the author's view that counterfeiting is a complex (i.e. wicked) problem, and that corporate, public policy and regulatory actions need to be mindful of how their actions may be causal. The paper offers a problem-based review of key components of this complexity, viz., the knowledge end-users/consumers have of medicines; whether restrictive information policies may hamper information provision to patients; the internet's direct access to consumers; internet-enabled distribution of unsafe and counterfeit medicines; whether the internet is a parallel and competitive supply chain to legitimate routes; organised crime as an emerging medicines manufacturer and supplier and whether substandard medicines is really the bigger problem. Solutions respect the perceived complexity of the supply chain challenges. The paper identifies the need to avoid technologically-driven solutions, calling for 'technological agnosticism'. Both regulation and public policy need to reflect the dynamic nature of the problem and avoid creating perverse incentives; it may be, for instance, that medicines pricing and reimbursement policies, which affect consumer/patient access may act as market signals to counterfeiters, since this creates a cash market in cheaper drugs.

  4. Evolution, opportunity and challenges of transboundary water and energy problems in Central Asia.

    Science.gov (United States)

    Guo, Lidan; Zhou, Haiwei; Xia, Ziqiang; Huang, Feng

    2016-01-01

    Central Asia is one of the regions that suffer the most prominent transboundary water and energy problems in the world. Effective transboundary water-energy resource management and cooperation are closely related with socioeconomic development and stability in the entire Central Asia. Similar to Central Asia, Northwest China has an arid climate and is experiencing a water shortage. It is now facing imbalanced supply-demand relations of water and energy resources. These issues in Northwest China and Central Asia pose severe challenges in the implementation of the Silk Road Economic Belt strategy. Based on the analysis of water and energy distribution characteristics in Central Asia as well as demand characteristics of different countries, the complexity of local transboundary water problems was explored by reviewing corresponding historical problems of involved countries, correlated energy issues, and the evolution of inter-country water-energy cooperation. With references to experiences and lessons of five countries, contradictions, opportunities, challenges and strategies for transboundary water-energy cooperation between China and Central Asia were discussed under the promotion of the Silk Road Economic Belt construction based on current cooperation conditions.

  5. The Evolution of Chemical High-Throughput Experimentation To Address Challenging Problems in Pharmaceutical Synthesis.

    Science.gov (United States)

    Krska, Shane W; DiRocco, Daniel A; Dreher, Spencer D; Shevlin, Michael

    2017-12-19

    The structural complexity of pharmaceuticals presents a significant challenge to modern catalysis. Many published methods that work well on simple substrates often fail when attempts are made to apply them to complex drug intermediates. The use of high-throughput experimentation (HTE) techniques offers a means to overcome this fundamental challenge by facilitating the rational exploration of large arrays of catalysts and reaction conditions in a time- and material-efficient manner. Initial forays into the use of HTE in our laboratories for solving chemistry problems centered around screening of chiral precious-metal catalysts for homogeneous asymmetric hydrogenation. The success of these early efforts in developing efficient catalytic steps for late-stage development programs motivated the desire to increase the scope of this approach to encompass other high-value catalytic chemistries. Doing so, however, required significant advances in reactor and workflow design and automation to enable the effective assembly and agitation of arrays of heterogeneous reaction mixtures and retention of volatile solvents under a wide range of temperatures. Associated innovations in high-throughput analytical chemistry techniques greatly increased the efficiency and reliability of these methods. These evolved HTE techniques have been utilized extensively to develop highly innovative catalysis solutions to the most challenging problems in large-scale pharmaceutical synthesis. Starting with Pd- and Cu-catalyzed cross-coupling chemistry, subsequent efforts expanded to other valuable modern synthetic transformations such as chiral phase-transfer catalysis, photoredox catalysis, and C-H functionalization. As our experience and confidence in HTE techniques matured, we envisioned their application beyond problems in process chemistry to address the needs of medicinal chemists. Here the problem of reaction generality is felt most acutely, and HTE approaches should prove broadly enabling

  6. Problems of reliability and economy work of thermal power plants water treatment based on baromembrane technologies

    Science.gov (United States)

    Chichirova, N. D.; Chichirov, A. A.; Saitov, S. R.

    2017-11-01

    The introduction of baromembrane water treatment technologies for water desalination at Russian thermal power plants was beganed more than 25 years ago. These technologies have demonstrated their definite advantage over the traditional technologies of additional water treatment for steam boilers. However, there are problems associated with the reliability and economy of their work. The first problem is a large volume of waste water (up to 60% of the initial water). The second problem a expensive and unique chemical reagents complex (biocides, antiscalants, washing compositions) is required for units stable and troublefree operation. Each manufacturer develops his own chemical composition for a certain membrane type. This leads to a significant increase in reagents cost, as well as creates dependence of the technology consumer on the certain supplier. The third problem is that the reliability of the baromembrane units depends directly on the water preliminary treatment. The popular pre-cleaning technology with coagulation of aluminum oxychloride proves to be unacceptable during seasonal changes in the quality of the source water at a number of stations. As a result, pollution, poisoning and lesion of the membrane structure or deterioration of their mechanical properties are observed. The report presents ways to solve these problems.

  7. Challenges in coupled thermal-hydraulics and neutronics simulations for LWR safety analysis

    International Nuclear Information System (INIS)

    Ivanov, Kostadin; Avramova, Maria

    2007-01-01

    The simulation of nuclear power plant accident conditions requires three-dimensional (3D) modeling of the reactor core to ensure a realistic description of physical phenomena. The operational flexibility of Light Water Reactor (LWR) plants can be improved by utilizing accurate 3D coupled neutronics/thermal-hydraulics calculations for safety margins evaluations. There are certain requirements to the coupling of thermal-hydraulic system codes and neutron-kinetics codes that ought to be considered. The objective of these requirements is to provide accurate solutions in a reasonable amount of CPU time in coupled simulations of detailed operational transient and accident scenarios. These requirements are met by the development and implementation of six basic components of the coupling methodologies: ways of coupling (internal or external coupling); coupling approach (integration algorithm or parallel processing); spatial mesh overlays; coupled time-step algorithms; coupling numerics (explicit, semi-implicit and implicit schemes); and coupled convergence schemes. These principles of the coupled simulations are discussed in details along with the scientific issues associated with the development of appropriate neutron cross-section libraries for coupled code transient modeling. The current trends in LWR nuclear power generation and regulation as well as the design of next generation LWR reactor concepts along with the continuing computer technology progress stimulate further development of these coupled code systems. These efforts have been focused towards extending the analysis capabilities as well as refining the scale and level of detail of the coupling. This article analyses the coupled phenomena and modeling challenges on both global (assembly-wise) and local (pin-wise) levels. The issues related to the consistent qualification of coupled code systems as well as their application to different types of LWR transients are presented. Finally, the advances in numerical

  8. Marine sampling in Malaysia coastal area: the challenge, problems and solution

    International Nuclear Information System (INIS)

    Norfaizal Mohamed; Khairul Nizam Razali; Mohd Rafaie Mohd Murtadza; Muhammad Amin Abdul Ghani; Zaharudin Ahmad; Abdul Kadir Ishak

    2005-01-01

    Malaysia Marine Radioactivity Database Development Project is one of the five research contracts that was signed between MINT and AELB. Three marine sampling expeditions had been carried out using K.L. PAUS vessel owned by Malaysian Fisheries Institute, Chendering, Terengganu. The first marine sampling expedition was taken place at East Coast Peninsular Malaysia waters on August 2003, followed on February 2004 at West Coast Peninsular Malaysia waters, and lastly at Sarawak-Sabah waters on July 2004. Many challenges and problems were faced when collecting sediment, water, biota and plankton sample during this marine sampling. (Author)

  9. Pressure sores–a constant problem for plegic patients and a permanent challenge for plastic surgery

    Science.gov (United States)

    Marinescu, S; Florescu, IP; Jecan, C

    2010-01-01

    Pressure sores–a constant problem for plegic patients and a permanent challenge for plastic surgery Pressure sores can be defined as lesions caused by unrelieved pressure resulting in damage of the underlying tissue. They represent a common problem in the pathology of plegic patients and, plastic surgery has a significant role in their treatment. Pressure sores occur over bony prominences and so, they are most commonly seen at the sacrum and trochanters in paralyzed patients and at ischium for the patients who sit in a wheelchair for a long time. For these patients, surgical treatment is very important because on one hand, it stops the loss of nutrients and proteins at the site of the pressure sore, and on the other hand, it permits the initiation of neuromuscular recuperation treatment much faster. PMID:20968200

  10. Response of Turkey Muscle Satellite Cells to Thermal Challenge. II. Transcriptome Effects in Differentiating Cells

    Directory of Open Access Journals (Sweden)

    Kent M. Reed

    2017-11-01

    Full Text Available Background: Exposure of poultry to extreme temperatures during the critical period of post-hatch growth can seriously affect muscle development and thus compromise subsequent meat quality. This study was designed to characterize transcriptional changes induced in turkey muscle satellite cells by thermal challenge during differentiation. Our goal is to better define how thermal stress alters breast muscle ultrastructure and subsequent development.Results: Skeletal muscle satellite cells previously isolated from the Pectoralis major muscle of 7-wk-old male turkeys (Meleagris gallopavo from two breeding lines: the F-line (16 wk body weight-selected and RBC2 (randombred control line were used in this study. Cultured cells were induced to differentiate at 38°C (control or thermal challenge temperatures of 33 or 43°C. After 48 h of differentiation, cells were harvested and total RNA was isolated for RNAseq analysis. Analysis of 39.9 Gb of sequence found 89% mapped to the turkey genome (UMD5.0, annotation 101 with average expression of 18,917 genes per library. In the cultured satellite cells, slow/cardiac muscle isoforms are generally present in greater abundance than fast skeletal isoforms. Statistically significant differences in gene expression were observed among treatments and between turkey lines, with a greater number of genes affected in the F-line cells following cold treatment whereas more differentially expressed (DE genes were observed in the RBC2 cells following heat treatment. Many of the most significant pathways involved signaling, consistent with ongoing cellular differentiation. Regulation of Ca2+ homeostasis appears to be significantly affected by temperature treatment, particularly cold treatment.Conclusions: Satellite cell differentiation is directly influenced by temperature at the level of gene transcription with greater effects attributed to selection for fast growth. At lower temperature, muscle-associated genes in the

  11. "It's Your Problem. Deal with It." Performers' Experiences of Psychological Challenges in Music.

    Science.gov (United States)

    Pecen, Ellis; Collins, David J; MacNamara, Áine

    2017-01-01

    Musicians need to deal with a range of challenges during their performance career and in response to these have reported a number of conditions that impact on their performance. Although social support from peers and teachers has been identified as part of the process of dealing with these challenges, little is understood about musicians' coping methods, beliefs and their attitudes toward support. Therefore, this study aimed to explore (a) performers' previous experiences of psychological challenges, (b) the types of support they used and, (c) how this might inform future support programs in learning environments. Fifteen interviews were conducted with pre-elite ( n = 5) transitioning elite ( n = 3) and established elite performers ( n = 7) in order to elicit data on psychological challenges, coping, beliefs and preferences for support. Inductive content analysis suggested that elite performers in this sample reported positive health habits, philosophical views of performance, health and life, positive anxiety reappraisal, and use of various psychological strategies, albeit without being explicitly aware of it. The need for various professional skills (e.g., communication, business, self-management, and organizational skills) was emphasized by all participants. Transition into conservatoire was marked by severe psychological challenges, disorders and trauma. Primary sources of support included friends, family and self-help literature. Professional help was predominantly sought for physical problems. The impact of teachers was paramount, yet securing good teachers was considered a matter of "luck." The most negative aspects recounted included abusive teachers, unsupportive environments, social comparison, competition, and disillusionment after entering the profession. Participants believed that talent could be developed and also valued wellbeing in relation to performance. Positive effects of late specialization on social development and professional skills were

  12. Problems of thermal IR-imaging in evaluation of burn wounds

    International Nuclear Information System (INIS)

    Nowakowski, A.

    2009-01-01

    Results of the research devoted to application of thermal IR-imaging in diagnostics of burn wounds are discussed. The main aim of the work was to develop an effective method for quantitative evaluation of the depth of a burn wound and for classification of regions for surgical treatment. The criterion of determination the area of the wound to be treated surgically is the time, which should not exceed three weeks for natural healing of a burn wound. Prediction that the healing process may last longer is concluded by immediate surgical intervention. We concentrate on using for this purpose QIRT - NDT TI methods (Quantitative Infra-Red Thermography - Non-Destructive Testing Thermal Imaging); especially - active dynamic thermography - ADT. In this work both, classical thermography using a high quality thermal camera as well as ADT are applied and the results of analysis are joined, allowing multimodality diagnostic approach and improved classification of burns requiring surgical treatment. Now our work in application of thermal imaging in determination of burns is continued for around 10 years, as the first publication showing our methodology was presented in 1999. In 2001, during the Thermosense conference, we have been awarded the Andronicos Kantsios Award for the work on Medical applications of model based dynamic thermography. Important reports of our experience in classical as well as ADT thermography are already published. Now we concentrate on practical aspects of the problem, trying to construct a measuring set to be operative even by not experienced staff and meeting all of necessary requirements for clinical applications. (author)

  13. Fundamental challenging problems for developing new nuclear safety standard computer codes

    International Nuclear Information System (INIS)

    Wong, P.K.; Wong, A.E.; Wong, A.

    2005-01-01

    Based on the claims of the US Basic patents number 5,084,232; 5,848,377 and 6,430,516 that can be obtained from typing the Patent Numbers into the Box of the Web site http://164.195.100.11/netahtml/srchnum.htm and their associated published technical papers having been presented and published at International Conferences in the last three years and that all these had been sent into US-NRC by E-mail on March 26, 2003 at 2:46 PM., three fundamental challenging problems for developing new nuclear safety standard computer codes had been presented at the US-NRC RIC2003 Session W4. 2:15-3:15 PM. at the Washington D.C. Capital Hilton Hotel, Presidential Ballroom on April 16, 2003 in front of more than 800 nuclear professionals from many countries worldwide. The objective and scope of this paper is to invite all nuclear professionals to examine and evaluate all the current computer codes being used in their own countries by means of comparison of numerical data from these three specific openly challenging fundamental problems in order to set up a global safety standard for all nuclear power plants in the world. (authors)

  14. Rethinking the globalisation of problem-based learning: how culture challenges self-directed learning.

    Science.gov (United States)

    Frambach, Janneke M; Driessen, Erik W; Chan, Li-Chong; van der Vleuten, Cees P M

    2012-08-01

    Medical schools worldwide are increasingly switching to student-centred methods such as problem-based learning (PBL) to foster lifelong self-directed learning (SDL). The cross-cultural applicability of these methods has been questioned because of their Western origins and because education contexts and learning approaches differ across cultures. This study evaluated PBL's cross-cultural applicability by investigating how it is applied in three medical schools in regions with different cultures in, respectively, East Asia, the Middle East and Western Europe. Specifically, it investigated how students' cultural backgrounds impact on SDL in PBL and how this impact affects students. A qualitative, cross-cultural, comparative case study was conducted in three medical schools. Data were collected through 88 semi-structured, in-depth interviews with Year 1 and 3 students, tutors and key persons involved in PBL, 32 observations of Year 1 and 3 PBL tutorials, document analysis, and contextual information. The data were thematically analysed using the template analysis method. Comparisons were made among the three medical schools and between Year 1 and 3 students across and within the schools. The cultural factors of uncertainty and tradition posed a challenge to Middle Eastern students' SDL. Hierarchy posed a challenge to Asian students and achievement impacted on both sets of non-Western students. These factors were less applicable to European students, although the latter did experience some challenges. Several contextual factors inhibited or enhanced SDL across the cases. As students grew used to PBL, SDL skills increased across the cases, albeit to different degrees. Although cultural factors can pose a challenge to the application of PBL in non-Western settings, it appears that PBL can be applied in different cultural contexts. However, its globalisation does not postulate uniform processes and outcomes, and culturally sensitive alternatives might be developed.

  15. The Near-Earth Orbital Debris Problem and the Challenges for Environment Remediation

    Science.gov (United States)

    Liou, Jer-Chyi

    2012-01-01

    The near-Earth space environment has been gradually polluted with orbital debris (OD) since the beginning of space activities 55 years ago. Although this problem has been known to the research community for decades, the public was, in general, unaware of the issue until the anti-satellite test conducted by China in 2007 and the collision between Cosmos 2251 and the operational Iridium 33 in 2009. The latter also underlined the potential of an ongoing collision cascade effect (the "Kessler Syndrome") in the low Earth orbit (LEO, the region below 2000 km altitude). Recent modeling results have indicated that mitigation measures commonly adopted by the international space community will be insufficient to stabilize the LEO debris population. To better limit the OD population increase, more aggressive actions must be considered. There are three options for OD environment remediation-removal of large/massive intact objects to address the root cause of the OD population growth problem, removal of 5-mm-to-1 cm debris to mitigate the main mission-ending threats for the majority of operational spacecraft, and prevention of major debris-generating collisions as a temporary means to slow down the OD population increase. The technology, engineering, and cost challenges to carry out any of these three options are monumental. It will require innovative ideas, game-changing technologies, and major collaborations at the international level to address the OD problem and preserve the near-Earth environment for future generations.

  16. Interpreting the Bible in the 'new' South Africa: Remarks on some problems and challenges

    Directory of Open Access Journals (Sweden)

    D. J. Human

    1997-12-01

    Full Text Available Interpreting the Bible in the 'new' South Africa DJ Human Department of Biblical Studies (Sec B University of Pretoria The Bible plays an important role in South African society. The interpretation of this book within or outside the Christian community has become an increaslingly major source of debate. It has been used and misused in several spheres of society. This article does not intend providing an extensive and composite picture of the problems and character of biblical hermeneutics. Nor will it attempt to elaborate on or explain the origins, development and influences of all the different her-meneutical approaches. Rather, it poses to be an introduction to a few of the problem(s encountered in the attempt to understand the Bible, especially in terms of the 'new' South Africa. Within the framework of this scope, remarks will be made regarding the challenges involved in interpreting the Bible, the role of the interpreter in the interpretation process, the varied forms of literature to be found in Scripture, and in the last instance, to take cognisance of a few methodological approaches to the text analysis of the Bible.

  17. Review of concentrating solar thermal power industry in China: Status quo, problems, trend and countermeasures

    Science.gov (United States)

    Zou, Jiajun

    2018-01-01

    Concentrating solar thermal power (CSP) industry is a strategic emerging industry in China. Its further development is of great significance for promoting the energy revolution, achieving energy saving and emission reduction. In this paper, China’s CSP industry is systematically analysed. First of all, the status quo is elaborated from the perspectives of relevant policies and regulations, market and generation technology development. Secondly, the problems and the underlying reasons of China’s CSP industry are deeply studied. On this basis, the future trends of CSP are expounded on the three levels of policy, market and power generation technology. Finally, a series of feasible countermeasures are put forward, designed to promote the development of CSP industry and the transformation of energy structure.

  18. Power Quality Problems Mitigation using Dynamic Voltage Restorer in Egypt Thermal Research Reactor (ETRR-2)

    International Nuclear Information System (INIS)

    Kandil, T.; Ayad, N.M.; Abdel Haleam, A.; Mahmoud, M.

    2013-01-01

    Egypt thermal research reactor (ETRR-2) was subjected to several Power Quality Problems such as voltage sags/swells, harmonics distortion, and short interruption. ETRR-2 encompasses a wide range of loads which are very sensitive to voltage variations and this leads to several unplanned shutdowns of the reactor due to trigger of the Reactor Protection System (RPS). The Dynamic Voltage Restorer (DVR) has recently been introduced to protect sensitive loads from voltage sags and other voltage disturbances. It is considered as one of the most efficient and effective solution. Its appeal includes smaller size and fast dynamic response to the disturbance. This paper describes a proposal of a DVR to improve power quality in ETRR-2 electrical distribution systems . The control of the compensation voltage is based on d-q-o algorithm. Simulation is carried out by Matlab/Simulink to verify the performance of the proposed method

  19. PREFACE: MicroTherm' 2013 - Microtechnology and Thermal Problems in Electronics

    Science.gov (United States)

    Lisik, Zbigniew; Raj, Ewa

    2014-04-01

    MicroTherm is an International Conference on Microtechnology and Thermal Problems in Electronics organised as a cyclic event since 1996. The success of the first seminar, which was devoted mainly to thermal management aspects, and the successive conferences have led us to the tenth edition. Since the first meeting, the scope of the conference has expanded, following the progress of electronics. Now, it covers subjects connected with extreme temperature, electronics, sensors and measurement techniques, modelling, simulation, wide band-gap materials, packaging and reliability, renewable energy sources and photonics with special emphasis on microelectronic technologies. MicroTherm' 2013 was held in Lodz, Poland, on 25-28 June 2013. The programme consistied of invited talks and nine regular sessions in the form of planar discussions and poster presentations, including a Students' Session. The Students' session gave an opportunity for students and young researchers to present their first achievements in the field of science. The next MicroTherm Conference is going to be held on 22-25 June 2015, in Lodz — a beautiful, post-industrial city located in the centre of Poland. Please, feel invited to MicroTherm' 2015 (www.microtherm.dsod.pl). Ewa Raj and Zbigniew Lisik Editors

  20. Simulation of Thermal Flow Problems via a Hybrid Immersed Boundary-Lattice Boltzmann Method

    Directory of Open Access Journals (Sweden)

    J. Wu

    2012-01-01

    Full Text Available A hybrid immersed boundary-lattice Boltzmann method (IB-LBM is presented in this work to simulate the thermal flow problems. In current approach, the flow field is resolved by using our recently developed boundary condition-enforced IB-LBM (Wu and Shu, (2009. The nonslip boundary condition on the solid boundary is enforced in simulation. At the same time, to capture the temperature development, the conventional energy equation is resolved. To model the effect of immersed boundary on temperature field, the heat source term is introduced. Different from previous studies, the heat source term is set as unknown rather than predetermined. Inspired by the idea in (Wu and Shu, (2009, the unknown is calculated in such a way that the temperature at the boundary interpolated from the corrected temperature field accurately satisfies the thermal boundary condition. In addition, based on the resolved temperature correction, an efficient way to compute the local and average Nusselt numbers is also proposed in this work. As compared with traditional implementation, no approximation for temperature gradients is required. To validate the present method, the numerical simulations of forced convection are carried out. The obtained results show good agreement with data in the literature.

  1. The NTF Inlet Guide Vanes Thermal Gradient Problem and Its Mitigation

    Science.gov (United States)

    Venkat, Venki S.; Paryz, Roman W.; Bissett, Owen W.; Kilgore, W.

    2013-01-01

    The National Transonic Facility (NTF) utilizes Inlet Guide Vanes (IGV) to provide precise, quick response Mach number control for the tunnel. During cryogenic operations, the massive IGV structure can experience large thermal gradients, measured as "Delta T or (Delta)T", between the IGV ring and its support structure called the transfer case. If these temperature gradients are too large, the IGV structure can be stressed beyond its safety limit and cease operation. In recent years, (Delta)T readings exceeding the prescribed safety limits were observed frequently during cryogenic operations, particularly during model access. The tactical operation methods of the tunnel to minimize (Delta)T did not always succeed. One obvious option to remedy this condition is to warm up the IGV structure by disabling the main drive operation, but this "natural" warm up method can takes days in some cases, resulting in productivity loss. This paper documents the thermal gradient problem associated with the IGV structure during cryogenic operation and how the facility has recently achieved an acceptable mitigation which has resulted in improved efficiency of operations.

  2. mathematical model of thermal explosion, the dual variational formulation of nonlinear problem, alternative functional

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    in its plane, and in the circular cylinder unlimited in length.An approximate numerical solution of the differential equation that is included in a nonlinear mathematical model of the thermal explosion enables us to obtain quantitative estimates of combination of determining parameters at which the limit state occurs in areas of not only canonical form. A capability to study of the thermal explosion state can be extended in the context of development of mathematical modeling methods, including methods of model analysis to describe the thermal state of solids.To analyse a mathematical model of the thermal explosion in a homogeneous solid the paper uses a variational approach based on the dual variational formulation of the appropriate nonlinear stationary problem of heat conduction in such a body. This formulation contains two alternative functional reaching the matching values in their stationary points corresponding to the true temperature distribution. This functional feature allows you to not only get an approximate quantitative estimate of the combination of parameters that determine the thermal explosion state, but also to find the greatest possible error in such estimation.

  3. Municipal solid waste management in the Southern Province of Sri Lanka: Problems, issues and challenges

    International Nuclear Information System (INIS)

    Vidanaarachchi, Chandana K.; Yuen, Samuel T.S.; Pilapitiya, Sumith

    2006-01-01

    This paper describes the problems, issues and challenges faced by Sri Lanka based on the outcome of a recent study conducted in the country's Southern Province. The study consists of a public survey, discussions with local authority staff involved in waste management, discussions with Provincial Council and Government officials, dialogue with local politicians, review of documents and field observations. The study revealed that only 24% of the households have access to waste collection and that in rural areas it was less than 2%. A substantial number of households in areas without waste collection expect local authorities to collect their waste. The study also showed that most sites in the province are under capacity to handle any increased demand. Urgent and immediate improvement of the waste disposal sites is necessary to meet the current demand for improved waste collection. The study also revealed that there is a high willingness of people for home composting

  4. Professional Education Management and Socio-Institutional Reality: problems and challenges

    Directory of Open Access Journals (Sweden)

    Eduardo Pinto e Silva

    2008-03-01

    Full Text Available The democratic management of educational practices is a theoretical and practical matter, which has been discussed in several institutional spheres (PARO, 2003; BORGES, GIUBILEI & OLIVEIRA, 2006. This paper deals with education management and is based on a case study about technical and professional education of agents of Municipal Guard (SILVA, 2005. This kind of education is affected by structural problems in the public institution (SANTOS, 1987 and in the macro judicial system (PINHEIRO, 1997, also being harmed by a process of social and work precariousness (ANTUNES, 1999; 2005. All these aspects represent challenges that have to be overcame. Thus, our propose of democratic professional education management (SILVA, 2005; HELOANI & SILVA, 2006 opposes the bureaucratic and alienating management. It demands listening to the collective subject and assuming a reflexive praxis about the professional activities and the socio-institutional reality. We consider that the challenge of creating a democratic professional management and a critical collective conscience, articulated with innovative actions, is part of a horizon of possibilities, even when it is mediated by institutional, organizational and cultural dimensions (SILVA JÚNIOR & FERRETTI, 2004.

  5. The microwave thermal thruster and its application to the launch problem

    Science.gov (United States)

    Parkin, Kevin L. G.

    Nuclear thermal thrusters long ago bypassed the 50-year-old specific impulse (Isp) limitation of conventional thrusters, using nuclear powered heat exchangers in place of conventional combustion to heat a hydrogen propellant. These heat exchanger thrusters experimentally achieved an Isp of 825 seconds, but with a thrust-to-weight ratio (T/W) of less than ten they have thus far been too heavy to propel rockets into orbit. This thesis proposes a new idea to achieve both high Isp and high T/W The Microwave Thermal Thruster. This thruster covers the underside of a rocket aeroshell with a lightweight microwave absorbent heat exchange layer that may double as a re-entry heat shield. By illuminating the layer with microwaves directed from a ground-based phased array, an Isp of 700--900 seconds and T/W of 50--150 is possible using a hydrogen propellant. The single propellant simplifies vehicle design, and the high Isp increases payload fraction and structural margins. These factors combined could have a profound effect on the economics of building and reusing rockets. A laboratory-scale microwave thermal heat exchanger is constructed using a single channel in a cylindrical microwave resonant cavity, and new type of coupled electromagnetic-conduction-convection model is developed to simulate it. The resonant cavity approach to small-scale testing reveals several drawbacks, including an unexpected oscillatory behavior. Stable operation of the laboratory-scale thruster is nevertheless successful, and the simulations are consistent with the experimental results. In addition to proposing a new type of propulsion and demonstrating it, this thesis provides three other principal contributions: The first is a new perspective on the launch problem, placing it in a wider economic context. The second is a new type of ascent trajectory that significantly reduces the diameter, and hence cost, of the ground-based phased array. The third is an eclectic collection of data, techniques, and

  6. The Compilation of the Shona–English Biomedical Dictionary: Problems and Challenges

    Directory of Open Access Journals (Sweden)

    Nomalanga Mpofu

    2011-10-01

    Full Text Available

    ABSTRACT: The bilingual Shona–English dictionary of biomedical terms, Duramazwi reUrapi neUtano, was compiled with the aim of improving the efficiency of communication between doctor and patient. The dictionary is composed of terms from both modern and traditional medicinal practices. The article seeks to look at the methods of production of the dictionary, the presentation of entries in the dictionary and the problems and challenges encountered in the compilation proc-ess, namely, developing Shona medical terminology in the cultural context and especially the as-pect of equivalence between English and Shona biomedical terms.

    Keywords: BIOMEDICAL, ADOPTIVES, ENTRIES, SYNONYMS, CROSS-REFERENCES, IDIOMS, CIRCUMLOCUTION, STANDARDISATION, HEADWORD, EQUIVALENCE, VARI-ANTS, DEFINITION, CULTURE, EUPHEMISMS, MODERN, TRADITIONAL, MONOLINGUAL, BILINGUAL, CORPUS, BORROWING, SHONA, COMMUNICATION

    *****

    OPSOMMING: Die samestelling van die Sjona–Engelse biomediese woorde-boek: Probleme en uitdagings. Die tweetalige Sjona–Engelse woordeboek van biomediese terme, Duramazwi reUrapi neUtano, is saamgestel met die doel om die effektiwiteit van kommunika-sie tussen dokter en pasiënt te verbeter. Die woordeboek bestaan uit terme van sowel moderne as tradisionele geneeskundige praktyke. Die artikel wil die metodes van die totstandkoming van die woordeboek beskou, die aanbieding van die inskrywings in die woordeboek en die probleme en uitdagings wat in die samestellingsproses teëgekom is, naamlik, die ontwikkeling van Sjona- mediese terminolgie binne die kulturele konteks en veral die aspek van ekwivalensie tussen Engel-se en Sjona- biomediese terme.

    Sleutelwoorde: BIOMEDIES, LEENWOORDE, INSKRYWINGS, SINONIEME, KRUISVER-WYSINGS, IDIOME, OMSKRYWING, STANDAARDISASIE, TREFWOORD, EKWIVALENSIE, WISSELVORME, DEFINISIE, KULTUUR, EUFEMISMES, MODERN, TRADISIONEEL, EEN-TALIG, TWEETALIG, KORPUS, ONTLENING, KOMMUNIKASIE, SJONA

  7. National Qualifications Framework For Higher Education in Turkey, and Architectural Education: Problems and Challenges of Implementation

    Directory of Open Access Journals (Sweden)

    Emel AKÖZER

    2013-01-01

    Full Text Available The Council of Higher Education (CoHE adopted the National Qualifications Framework for Higher Education in Turkey (NQF-HETR in May 2009, as part of the Bologna reforms. In January 2010, the CoHE decided full implementation of the NQF-HETR at institutional and program levels and in this decision, it was foreseen that the process would be completed by the end of December 2012. The NQFHETR has been aligned both to the overarching Framework for Qualifications in the European Higher Education Area (QF-EHEA, 2005 and to the European Qualifications Framework for lifelong learning (EQF-LLL, 2008. The latter was introduced to facilitate the European cooperation in education and training, in line with the goals of the European Union's (EU Lisbon Strategy. This paper focuses on some of the problems that have become apparent during the NQF-HETR's implementation at the levels of “narrow fields of education” and architecture programs, and the challenges ahead. Following a discussion of the significance of the two European frameworks in light of the goals of the EHEA, the Education and Training 2010 work programme (ET 2010 and the strategic framework for European cooperation in Education and Training (ET 2020, it covers two problem areas concerning qualifications in architecture: i terminological and classificatory problems entailed by the NQF-HETR; ii the lack of alignment between the European qualifications frameworks and the EU Directive on the Recognition of Professional Qualifications (Directive EC/2005/36 that covers seven “sectoral professions” including architecture. The paper also reviews the latest developments for the modernization of the EU Directive in order to provide progression in forming an integrated European Higher Education Area.

  8. [Evolution of methodical approaches to solve problem of evaluating and predicting the thermal status of cosmonauts in the real flight].

    Science.gov (United States)

    Kuznets, E I; Bobrov, A F; Bekreneva, L N; Mikhailova, L I; Utekhin, B A; Pruzhinina, T I; Iakovleva, E V; Chadov, V I

    1996-01-01

    The problem of evaluating and predicting the thermal status of a cosmonaut in the long-term space mission is a pressing one and remains to be solved. The previous studies indicated that the best plan to be followed is to evaluate the thermal status of a cosmonaut during his egress into outer space with the use of the procedure of parotid thermometry of the mean body temperature.

  9. SU-E-J-161: Inverse Problems for Optical Parameters in Laser Induced Thermal Therapy

    International Nuclear Information System (INIS)

    Fahrenholtz, SJ; Stafford, RJ; Fuentes, DT

    2014-01-01

    Purpose: Magnetic resonance-guided laser-induced thermal therapy (MRgLITT) is investigated as a neurosurgical intervention for oncological applications throughout the body by active post market studies. Real-time MR temperature imaging is used to monitor ablative thermal delivery in the clinic. Additionally, brain MRgLITT could improve through effective planning for laser fiber's placement. Mathematical bioheat models have been extensively investigated but require reliable patient specific physical parameter data, e.g. optical parameters. This abstract applies an inverse problem algorithm to characterize optical parameter data obtained from previous MRgLITT interventions. Methods: The implemented inverse problem has three primary components: a parameter-space search algorithm, a physics model, and training data. First, the parameter-space search algorithm uses a gradient-based quasi-Newton method to optimize the effective optical attenuation coefficient, μ-eff. A parameter reduction reduces the amount of optical parameter-space the algorithm must search. Second, the physics model is a simplified bioheat model for homogeneous tissue where closed-form Green's functions represent the exact solution. Third, the training data was temperature imaging data from 23 MRgLITT oncological brain ablations (980 nm wavelength) from seven different patients. Results: To three significant figures, the descriptive statistics for μ-eff were 1470 m −1 mean, 1360 m −1 median, 369 m −1 standard deviation, 933 m −1 minimum and 2260 m −1 maximum. The standard deviation normalized by the mean was 25.0%. The inverse problem took <30 minutes to optimize all 23 datasets. Conclusion: As expected, the inferred average is biased by underlying physics model. However, the standard deviation normalized by the mean is smaller than literature values and indicates an increased precision in the characterization of the optical parameters needed to plan MRgLITT procedures. This investigation

  10. Potential and Challenges of Web-based Collective Intelligence to Tackle Societal Problems

    Directory of Open Access Journals (Sweden)

    Birutė Pitrėnaitė-Žilėnienė

    2014-03-01

    Full Text Available Purpose – to research what are conditions and challenges for collective intelligence (hereinafter – CI, i.e., emerging applying social technologies, to tackle societal problems. Several objectives were set in order to achieve the goal: to analyze the scientific concepts of CI and its contents; to summarize possibilities and challenges of application of CI in largescale online argumentation; following theoretical attitudes towards CI, to analyze Lithuanian praxis of application of CI technologies in large-scale online argumentation.Methodology – the methods of document analysis and content analysis of virtual community projects were applied. Theoretical analysis enabled recognition of CI phenomena and the variety of interpretations on CI as well as preconditions and difficulties to be tackled in order to ensure effective application of CI technologies in the processes of different policies design and/or societal problem solving. Having theoretical analysis as a base, the authors researched how the theoretical frameworks correspond to practices of Lithuanian virtual community projects, which are oriented to identification and analysis of relevant problems that communities are facing.Findings – scientific documents analysis demonstrates the variety of possible interpretations of CI. Such interpretations depend on the researcher’s attitudes towards this phenomenon: some authors explain CI in a very broad sense not including the aspects of social technologies. However, in the last decades, with the emergence of the Internet, social technologies have become concurrent dimension of CI. The main principles of Web-based CI are geographically spread users and a big number of them. Materialization of these principles ensures variety of elements needed for emerging of CI. There are diverse web-based mediums, where CI is being developed. However, not all of them ensure collective action, which is obligatory for CI. Researchers have analyzed

  11. NASTRAN thermal analyzer: Theory and application including a guide to modeling engineering problems, volume 1. [thermal analyzer manual

    Science.gov (United States)

    Lee, H. P.

    1977-01-01

    The NASTRAN Thermal Analyzer Manual describes the fundamental and theoretical treatment of the finite element method, with emphasis on the derivations of the constituent matrices of different elements and solution algorithms. Necessary information and data relating to the practical applications of engineering modeling are included.

  12. Changes, Problems, and Challenges in Swedish Spatial Planning—An Analysis of Power Dynamics

    Directory of Open Access Journals (Sweden)

    Till Koglin

    2017-10-01

    Full Text Available During the past few decades, the Swedish spatial planning system has experienced numerous problems and challenges. In particular, there have been changes in legislation and an increased neoliberalisation of planning that gives private actors a larger influence over the planning processes in Sweden. In this article, we analyse these changes through the lenses of collaborative and neoliberal planning in order to illuminate the shifting power relations within spatial planning in Sweden. We analyse the changes of power relations from three dimensions of power based on interviews with different kinds of planners throughout Sweden. We show that power relations in the Swedish spatial planning system have shifted and that neoliberalisation and an increased focus on collaborative planning approaches have made spatial planning more complex in recent decades. This has led to a change of role for planners form actual planners to collaborators. We conclude that market-oriented planning (neoliberal planning and collaborative planning have made it more difficult for spatial planners in Sweden to work towards sustainable urban futures.

  13. Stabilized FE simulation of prototype thermal-hydraulics problems with integrated adjoint-based capabilities

    International Nuclear Information System (INIS)

    Shadid, J.N.; Smith, T.M.; Cyr, E.C.; Wildey, T.M.; Pawlowski, R.P.

    2016-01-01

    A critical aspect of applying modern computational solution methods to complex multiphysics systems of relevance to nuclear reactor modeling, is the assessment of the predictive capability of specific proposed mathematical models. In this respect the understanding of numerical error, the sensitivity of the solution to parameters associated with input data, boundary condition uncertainty, and mathematical models is critical. Additionally, the ability to evaluate and or approximate the model efficiently, to allow development of a reasonable level of statistical diagnostics of the mathematical model and the physical system, is of central importance. In this study we report on initial efforts to apply integrated adjoint-based computational analysis and automatic differentiation tools to begin to address these issues. The study is carried out in the context of a Reynolds averaged Navier–Stokes approximation to turbulent fluid flow and heat transfer using a particular spatial discretization based on implicit fully-coupled stabilized FE methods. Initial results are presented that show the promise of these computational techniques in the context of nuclear reactor relevant prototype thermal-hydraulics problems.

  14. Stabilized FE simulation of prototype thermal-hydraulics problems with integrated adjoint-based capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Shadid, J.N., E-mail: jnshadi@sandia.gov [Sandia National Laboratories, Computational Mathematics Department (United States); Department of Mathematics and Statistics, University of New Mexico (United States); Smith, T.M. [Sandia National Laboratories, Multiphysics Applications Department (United States); Cyr, E.C. [Sandia National Laboratories, Computational Mathematics Department (United States); Wildey, T.M. [Sandia National Laboratories, Optimization and UQ Department (United States); Pawlowski, R.P. [Sandia National Laboratories, Multiphysics Applications Department (United States)

    2016-09-15

    A critical aspect of applying modern computational solution methods to complex multiphysics systems of relevance to nuclear reactor modeling, is the assessment of the predictive capability of specific proposed mathematical models. In this respect the understanding of numerical error, the sensitivity of the solution to parameters associated with input data, boundary condition uncertainty, and mathematical models is critical. Additionally, the ability to evaluate and or approximate the model efficiently, to allow development of a reasonable level of statistical diagnostics of the mathematical model and the physical system, is of central importance. In this study we report on initial efforts to apply integrated adjoint-based computational analysis and automatic differentiation tools to begin to address these issues. The study is carried out in the context of a Reynolds averaged Navier–Stokes approximation to turbulent fluid flow and heat transfer using a particular spatial discretization based on implicit fully-coupled stabilized FE methods. Initial results are presented that show the promise of these computational techniques in the context of nuclear reactor relevant prototype thermal-hydraulics problems.

  15. Thermal Protection for Mars Sample Return Earth Entry Vehicle: A Grand Challenge for Design Methodology and Reliability Verification

    Science.gov (United States)

    Venkatapathy, Ethiraj; Gage, Peter; Wright, Michael J.

    2017-01-01

    Mars Sample Return is our Grand Challenge for the coming decade. TPS (Thermal Protection System) nominal performance is not the key challenge. The main difficulty for designers is the need to verify unprecedented reliability for the entry system: current guidelines for prevention of backward contamination require that the probability of spores larger than 1 micron diameter escaping into the Earth environment be lower than 1 million for the entire system, and the allocation to TPS would be more stringent than that. For reference, the reliability allocation for Orion TPS is closer to 11000, and the demonstrated reliability for previous human Earth return systems was closer to 1100. Improving reliability by more than 3 orders of magnitude is a grand challenge indeed. The TPS community must embrace the possibility of new architectures that are focused on reliability above thermal performance and mass efficiency. MSR (Mars Sample Return) EEV (Earth Entry Vehicle) will be hit with MMOD (Micrometeoroid and Orbital Debris) prior to reentry. A chute-less aero-shell design which allows for self-righting shape was baselined in prior MSR studies, with the assumption that a passive system will maximize EEV robustness. Hence the aero-shell along with the TPS has to take ground impact and not break apart. System verification will require testing to establish ablative performance and thermal failure but also testing of damage from MMOD, and structural performance at ground impact. Mission requirements will demand analysis, testing and verification that are focused on establishing reliability of the design. In this proposed talk, we will focus on the grand challenge of MSR EEV TPS and the need for innovative approaches to address challenges in modeling, testing, manufacturing and verification.

  16. Enhancing Cross-functional Collaboration and Effective Problem Solving Through an Innovation Challenge for Point-of-Care Providers.

    Science.gov (United States)

    Bakallbashi, Eni; Vyas, Anjali; Vaswani, Nikita; Rosales, David; Russell, David; Dowding, Dawn; Bernstein, Michael; Abdelaal, Hany; Hawkey, Regina

    2015-01-01

    An internal employee challenge competition is a way to promote staff engagement and generate innovative business solutions. This Spotlight on Leadership focuses on the approach that a large not-for-profit healthcare organization, the Visiting Nurse Service of New York, took in designing and executing an innovation challenge. The challenge leveraged internal staff expertise and promoted wide participation. This model is 1 that can be replicated by organizations as leaders work to engage employees at the point of service in organization-wide problem solving.

  17. Problems, Challenges and Benefits of Implementing E-learning in Nigerian Universities: An Empirical Study

    Directory of Open Access Journals (Sweden)

    Manir Abdullahi Kamba

    2009-03-01

    Full Text Available This paper tries to examine and discuss the problems, challenges and Benefits of implementing E-Learning in Nigeria by reviewing the consciousness and willingness of the selected Universities. This study also identifies the enabling factors, the traffic-jam and, forecasts the future growth of E-learning in Nigeria. Survey research method was adopted for the study, and questionnaire was the only instrument used for the data collection. The findings of the study show that out of the 18 universities selected from different specialization areas, i.e three universities from each Geopolitical zone, only 12 responded with usable answers. The response rate was 67%, which is an expected rate for such surveys. Awareness of e-learning among the Universities is very high but investment and commitment to develop an e-learning application is very poor and below expectation according to the study. Most of the staff and students in the universities only use Internet related e- learning site just for the sake of finding related information for their researches, since their libraries cannot afford to provide them with adequate and current materials but not for the sake of real online learning. The study also found out that some of the universities have web page and others are in the trend of creating a web page, which is usually for advertisement of the universities but not for the e-leaning activities. Furthermore, the findings also reveal that staff and the students have also been using e-mail and Internet in addition to developing web pages for transaction of students. The Universities are planning to invest number of funds in future in the selected areas of the e-learning application. The Statistical analysis result shows that there are significant differences across both forms of e-learning activities and type of universities in Nigeria.

  18. Problems of solid waste management on Mount Kilimanjaro: a challenge to tourism.

    Science.gov (United States)

    Kaseva, Mengiseny E; Moirana, Josia L

    2010-08-01

    We report on the findings of a study on the problems of solid waste management (SWM) on Mountain Kilimanjaro (MK) which is located within Kilimanjaro National Park (KINAPA) in Northern Tanzania. The study was prompted by the fact that flourishing tourism on the mountain over the years has resulted in an increase in the tonnage of solid waste (SW) generated, posing serious challenges in its collection and disposal. The methodology employed in this study included physical observations and questionnaire surveys, as well as waste sorting and weighing to quantify and characterize waste loads collected from each tourist route station covered in this study. On the basis of the established SW generation rate (0.6 kg ca(-1) day(-1)) a total amount of SW generated was estimated to range from about 87 tones (in 2003) to 125 tones (in 2006). An improvement in SW collection from 64% in 2003 to 94% in 2006 was also noted. This improvement can be attributed to the trash-in-trash-out (TITO) system of SW collection which is currently practiced by the management of KINAPA for SWM on MK. The study also highlights potential environmental pollution including air pollution from open burning and pit disposal of SW. Based on average percentage values of waste components and the estimated quantity of waste generated, it was established that the total waste quantum contains about 34% of recyclables. The study recommends that resource recovery and conservation measures through waste recycling and re-use be instituted as one of the options for sustainable SWM on MK.

  19. Contribution to the study of thermal-hydraulic problems in nuclear reactors; Contribution a l`etude de problemes de thermohydraulique dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, G

    1998-07-07

    In nuclear reactors, whatever the type considered, Pressurized Water Water Reactors (PWRs), Fast Breeder reactors (FBRs)..., thermal-hydraulics, the science of fluid mechanics and thermal behaviour, plays an essential role, both in nominal operating and accidental conditions. Fluid can either be the primary fluid (liquid or gas) or a very specific fluid called corium, which, in case of severe accident, could result from core and environning structure melting. The work reported here represents a 20-year contribution to thermal-hydraulic issues which could occur in FBRs and PWRs. Working on these two types of reactors, both in nominal and severe accident situations, has allowed me to compare the problems and to realize the importance of communication between research teams. The evolution in the complexity of studied problems, unavoidable in order to reduce costs and significantly improve safety, has led me from numerical modelling of single-phase flow turbulence to high temperature real melt experiments. The difficulties encountered in understanding the observed phenomena and in increasing experimental databases for computer code qualification have often entailed my participation in specific measurement device developments or adaptations, in particular non-intrusive devices generally based on optical techniques. Being concerned about the end-use of this research work, I actively participated in `in-situ` thermalhydraulic experiments in the FBRs: Phenix and Super-Phenix, of which I appreciated their undeniable scientific contribution. In my opinion, the thermal-hydraulic questions related to severe accidents are the most complex as they are at the cross-roads of several scientific specialities. Consequently, they require a multi-disciplinary approach and a continuous see-saw motion between experimentalists and modelling teams. After a brief description of the various problems encountered, the main ones are reported. Finally, the importance for research teams to

  20. Verification of thermal-hydraulic computer codes against standard problems for WWER reflooding

    International Nuclear Information System (INIS)

    Alexander D Efanov; Vladimir N Vinogradov; Victor V Sergeev; Oleg A Sudnitsyn

    2005-01-01

    Full text of publication follows: The computational assessment of reactor core components behavior under accident conditions is impossible without knowledge of the thermal-hydraulic processes occurring in this case. The adequacy of the results obtained using the computer codes to the real processes is verified by carrying out a number of standard problems. In 2000-2003, the fulfillment of three Russian standard problems on WWER core reflooding was arranged using the experiments on full-height electrically heated WWER 37-rod bundle model cooldown in regimes of bottom (SP-1), top (SP-2) and combined (SP-3) reflooding. The representatives from the eight MINATOM's organizations took part in this work, in the course of which the 'blind' and posttest calculations were performed using various versions of the RELAP5, ATHLET, CATHARE, COBRA-TF, TRAP, KORSAR computer codes. The paper presents a brief description of the test facility, test section, test scenarios and conditions as well as the basic results of computational analysis of the experiments. The analysis of the test data revealed a significantly non-one-dimensional nature of cooldown and rewetting of heater rods heated up to a high temperature in a model bundle. This was most pronounced at top and combined reflooding. The verification of the model reflooding computer codes showed that most of computer codes fairly predict the peak rod temperature and the time of bundle cooldown. The exception is provided by the results of calculations with the ATHLET and CATHARE codes. The nature and rate of rewetting front advance in the lower half of the bundle are fairly predicted practically by all computer codes. The disagreement between the calculations and experimental results for the upper half of the bundle is caused by the difficulties of computational simulation of multidimensional effects by 1-D computer codes. In this regard, a quasi-two-dimensional computer code COBRA-TF offers certain advantages. Overall, the closest

  1. The Challenge of Assessing Creative Problem Solving in Client-Based Marketing Development Projects: A SOLO Taxonomy Approach

    Science.gov (United States)

    Jaskari, Minna-Maarit

    2013-01-01

    Creativity and marketing imagination are essential core competencies for marketers. Therefore, higher marketing education emphasizes creativity in several ways. However, assessing creativity and creative problem solving is challenging and tools for this purpose have not been developed in the context of marketing education. To address this gap, we…

  2. Associations between Mental Health Problems and Challenging Behavior in Adults with Intellectual Disabilities: A Test of the Behavioral Equivalents Hypothesis

    Science.gov (United States)

    Painter, Jon; Hastings, Richard; Ingham, Barry; Trevithick, Liam; Roy, Ashok

    2018-01-01

    Introduction: Current research findings in the field of intellectual disabilities (ID) regarding the relationship between mental health problems and challenging behavior are inconclusive and/or contradictory. The aim of this study was to further investigate the putative association between these two highly prevalent phenomena in people with ID,…

  3. electrical-thermal coupling of induction machine for improved

    African Journals Online (AJOL)

    user

    parameter method was used in the thermal model of the machine. The system of ... Thermal modeling is important for design purpose, fault detection ... dependent problems are challenging both in software development ... numerical solution.

  4. Subject Access Problems of Different Types of OPAC Users Or, the Double Challenge.

    Science.gov (United States)

    Cochrane, Pauline A.

    1989-01-01

    Reviews the problems of users of online public access catalogs and argues that it is necessary to think of all searching problems as systems problems rather than user failures, and to concentrate research in the area of systems enhancements. A list of improved tools needed for subject searching in online catalogs is identified. (CLB)

  5. Challenges in thermal design of industrial single-phase power inverter

    Directory of Open Access Journals (Sweden)

    Ninković Predrag

    2016-01-01

    Full Text Available This paper presents the influence of thermal aspects in design process of an industrial single-phase inverter, choice of its topology and components. Stringent design inputs like very high overload level, demand for natural cooling and very wide input voltage range have made conventional circuit topology inappropriate therefore asking for alternative solution. Different power losses calculations in semiconductors are performed and compared, outlining the guidelines how to choose the final topology. Some recommendations in power magnetic components design are given. Based on the final project, a 20kVA single-phase inverter for thermal power plant supervisory and control system is designed and commissioned.

  6. Thermal management of hybrid vehicles. Challenges and solutions; Thermomanagement von Hybridfahrzeugen. Herausforderungen und Loesungen

    Energy Technology Data Exchange (ETDEWEB)

    Heckenberger, T. [Behr GmbH und Co. KG, Stuttgart (Germany)

    2007-10-15

    Higher thermal management demands are placed on hybrid vehicles than on conventional vehicles. The thermal comfort of the passengers must be assured when the combustion engine shuts down, i.e. during start-stop phases and during purely electric driving. Likewise, the particular hybrid modules and components must be cooled to temperature levels that are too low for conventional cooling circuits. Behr is presently developing cooling and climate control systems for all three types of hybrid vehicles: micro-, mild, and full hybrids. (orig.)

  7. Comments on an Analytical Thermal Agglomeration for Problems with Surface Growth

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-03-22

    Up until Dec 2016, the thermal agglomeration was very heuristic, and as such, difficult to define. The lack of predictability became problematic, and the current notes represent the first real attempt to systematize the specification of the agglomerated process parameters.

  8. The Proxy Challenge: Why bespoke proxy indicators can help solve the anti-corruption measurement problem

    OpenAIRE

    Johnsøn, Jesper; Mason, Phil

    2013-01-01

    Practitioners working in anti-corruption face perennial challenges in measuring changes in corruption levels and evaluating whether anti-corruption efforts are successful. These two challenges are linked but not inseparable. To make progress on the latter front, that is, evaluating whether anti-corruption efforts are having an impact, the U4 Anti-Corruption Resource Centre and the UK Department for International Development are launching an exploration into the use of proxy indicators. Proxy ...

  9. Ghana's National Health Insurance Scheme: an assessment of problems and challenges

    OpenAIRE

    Danquah, Jones Kwame Adom

    2017-01-01

    Despite impressive progress since 2003, huge challenges remain in the effort to improve health outcomes in Ghana and achieve related goals concerning universal coverage, basic needs, equity, inclusion, risk protection and reaching poor and marginalized groups. One of these challenges is how health should be financed – who should pay how much and through what arrangements, given the reality that the services and other actions needed to attain desired health results inevitably involve costs tha...

  10. Homogenization of a thermal problem with the fourier conditions in the thin plates of a heat exchanger

    International Nuclear Information System (INIS)

    Rahmattulla, A.A.; Taghite, M.B.

    1996-01-01

    In this paper was studied a thermal problem with the fourier boundary conditions on the edges of the holes in a periodically perforated plate of a heat exchanger. This problem contains several reduced parameters which can be very small (the period ε of the distribution of the holes, the reduced thickness e of the plate and the three Biot numbers relative to the different parts of the boundary). The homogenization technique was used to estimate the field of temperatures attainable in the upper plate, depending on the relative order of magnitude of the smell parameters. (authors). 9 refs

  11. Addressing Complex Challenges through Adaptive Leadership: A Promising Approach to Collaborative Problem Solving

    Science.gov (United States)

    Nelson, Tenneisha; Squires, Vicki

    2017-01-01

    Organizations are faced with solving increasingly complex problems. Addressing these issues requires effective leadership that can facilitate a collaborative problem solving approach where multiple perspectives are leveraged. In this conceptual paper, we critique the effectiveness of earlier leadership models in tackling complex organizational…

  12. Teachers Implementing Mathematical Problem Posing in the Classroom: Challenges and Strategies

    Science.gov (United States)

    Leung, Shuk-kwan S.

    2013-01-01

    This paper reports a study about how a teacher educator shared knowledge with teachers when they worked together to implement mathematical problem posing (MPP) in the classroom. It includes feasible methods for getting practitioners to use research-based tasks aligned to the curriculum in order to encourage children to pose mathematical problems.…

  13. Social Issues and Problem-Based Learning in Sociology: Opportunities and Challenges in the Undergraduate Classroom

    Science.gov (United States)

    Eglitis, Daina S.; Buntman, Fran L.; Alexander, Dameon V.

    2016-01-01

    This article discusses the use of problem-based learning (PBL) in the undergraduate sociology classroom. PBL shifts students from the role of passive listeners and learners to active knowledge builders and communicators through the use of concise and engaging social problem cases. PBL creates opportunities for building substantive area knowledge,…

  14. Understanding wicked problems and organized irresponsibility: challenges for governing the sustainable intensification of chicken meat production

    NARCIS (Netherlands)

    Bueren, E.M.; Lammerts Van Bueren, E.; Zijpp, van der A.J.

    2014-01-01

    Framing sustainable intensification as a wicked problem reveals how inherent trade-offs and resulting uncertainty and ambiguity block integrated problem solving as promoted by sustainable chain management approaches to production and consumption. The fragmented institutional set-up of the chains

  15. Solving algebraic computational problems in geodesy and geoinformatics the answer to modern challenges

    CERN Document Server

    Awange, Joseph L

    2004-01-01

    While preparing and teaching 'Introduction to Geodesy I and II' to - dergraduate students at Stuttgart University, we noticed a gap which motivated the writing of the present book: Almost every topic that we taughtrequiredsomeskillsinalgebra,andinparticular,computeral- bra! From positioning to transformation problems inherent in geodesy and geoinformatics, knowledge of algebra and application of computer algebra software were required. In preparing this book therefore, we haveattemptedtoputtogetherbasicconceptsofabstractalgebra which underpin the techniques for solving algebraic problems. Algebraic c- putational algorithms useful for solving problems which require exact solutions to nonlinear systems of equations are presented and tested on various problems. Though the present book focuses mainly on the two ?elds,theconceptsand techniquespresented hereinarenonetheless- plicable to other ?elds where algebraic computational problems might be encountered. In Engineering for example, network densi?cation and robo...

  16. Continuous Measurements and Quantitative Constraints: Challenge Problems for Discrete Modeling Techniques

    Science.gov (United States)

    Goodrich, Charles H.; Kurien, James; Clancy, Daniel (Technical Monitor)

    2001-01-01

    We present some diagnosis and control problems that are difficult to solve with discrete or purely qualitative techniques. We analyze the nature of the problems, classify them and explain why they are frequently encountered in systems with closed loop control. This paper illustrates the problem with several examples drawn from industrial and aerospace applications and presents detailed information on one important application: In-Situ Resource Utilization (ISRU) on Mars. The model for an ISRU plant is analyzed showing where qualitative techniques are inadequate to identify certain failure modes and to maintain control of the system in degraded environments. We show why the solution to the problem will result in significantly more robust and reliable control systems. Finally, we illustrate requirements for a solution to the problem by means of examples.

  17. Investigation of V and V process for thermal fatigue issue in a sodium cooled fast reactor – Application of uncertainty quantification scheme in verification and validation with fluid-structure thermal interaction problem in T-junction piping system

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masaaki, E-mail: tanaka.masaaki@jaea.go.jp

    2014-11-15

    Highlights: • Outline of numerical simulation code MUGTHES for fluid-structure thermal interaction was described. • The grid convergence index (GCI) method was applied according to the ASME V and V-20 guide. • Uncertainty of MUGTHES can be successfully quantified for thermal-hydraulic problems and unsteady heat conduction problems in the structure. • Validation for fluid-structure thermal interaction problem in a T-junction piping system was well conducted. - Abstract: Thermal fatigue caused by thermal mixing phenomena is one of the most important issues in design and safety assessment of fast breeder reactors. A numerical simulation code MUGTHES consisting of two calculation modules for unsteady thermal-hydraulics analysis and unsteady heat conduction analysis in structure has been developed to predict thermal mixing phenomena and to estimate thermal response of structure under the thermal interaction between fluid and structure fields. Although verification and validation (V and V) of MUGTHES has been required, actual procedure for uncertainty quantification is not fixed yet. In order to specify an actual procedure of V and V, uncertainty quantifications with the grid convergence index (GCI) estimation according to the existing guidelines were conducted in fundamental laminar flow problems for the thermal-hydraulics analysis module, and also uncertainty for the structure heat conduction analysis module and conjugate heat transfer model was quantified in comparison with the theoretical solutions of unsteady heat conduction problems. After the verification, MUGTHES was validated for a practical fluid-structure thermal interaction problem in T-junction piping system compared with measured results of velocity and temperatures of fluid and structure. Through the numerical simulations in the verification and validation, uncertainty of the code was successfully estimated and applicability of the code to the thermal fatigue issue was confirmed.

  18. Medialogy – An Interdisciplinary Education Challenge in a Problem Based Learning Environment

    DEFF Research Database (Denmark)

    Nordahl, Rolf; Kofoed, Lise B.

    2012-01-01

    Different new educations in the field of media and technology are constantly developing worldwide. Searching on the Internet almost every university has programs in both media and communication. Several universities are discussing the challenges to offer double degrees, so the students can combine...... an individual education according to their interests. Other universities are offering interdisciplinary educations in the field of media technology. Having worked with those interdisciplinary engineering and science educations for several years, it seems to be a challenge to define the students’ key competences......, and the ability of such educations to provide new scientific paradigms and disciplines. This paper investigates the challenges connected to a new interdisciplinary science and engineering program: Medialogy at Aalborg University. The program includes Bachelor and Master level educations and combines humanistic...

  19. On The Cusp of the New Spatial Challenges - The Thermal Waste Processing Plant as an Element of Urban Space

    Science.gov (United States)

    Wójtowicz-Wróbel, Agnieszka

    2017-10-01

    The goal of this paper is to answer the question about the current importance of structures associated with the thermal processing of waste within the space of Polish cities and what status can they have in the functional and spatial structure of Polish cities in the future. The construction of thermal waste processing plants in Poland is currently a new and important problem, with numerous structures of this type being built due to increasing care for the natural environment, with the introduction of legal regulations, as well as due to the possibility of obtaining large external funding for the purposes of undertaking pro-environmental spatial initiatives, etc. For this reason, the paper contains research on the increase in the number of thermal waste processing plants in Poland in recent years. The abovementioned data was compared with similar information from other European Union member states. In the group containing Polish thermal waste processing plants, research was performed regarding the stage of the construction of a plant (operating plant, plant under construction, design in a construction phase, etc.). The paper also contains a listing of the functions other than the basic form of use, which is the incineration of waste - similarly to numerous foreign examples - that the environmentally friendly waste incineration plants fulfil in Poland, dividing the additional forms of use into "hard" elements (at the design level, requiring the expansion of a building featuring new elements that are not directly associated with the basic purpose of waste processing) and soft (social, educational, promotional actions, as well as other endeavours that require human involvement, but that do not entail significant design work on the buildings itself, expanding its form of use, etc.) as well as mixed activity, which required design work, but on a relatively small scale. Research was also conducted regarding the placement of thermal waste processing plants within the

  20. Public Health Insurance in Vietnam towards Universal Coverage: Identifying the challenges, issues, and problems in its design and organizational practices

    OpenAIRE

    Midori Matsushima; Hiroyuki Yamada

    2013-01-01

    Vietnam is attempting to achieve universal health insurance coverage by 2014. Despite great progress, the country faces some challenges, issues and problems. This paper reviewed official documents, existing reports, and related literature to address: (1) grand design for achieving universal health coverage, (2) current insurance coverage, (3) health insurance premium and subsidies by the government, (4) benefit package and payment rule, and (5) organizational practices. From the review, it be...

  1. Identifying and evaluating high risk areas and challenges on marine drilling riser system in relation to deepwater problems

    OpenAIRE

    Iversen, Alexander

    2012-01-01

    Master's thesis in Offshore technology The main concerns during drilling operations are riser integrity and maintaining well control. This thesis has mainly been focusing on the problems and challenges faced with the marine riser system to illuminate high risk areas related to riser integrity. A marine riser system consists generally of four main elements; the upper marine riser package, riser joints, lower marine riser package, and the blowout preventer, each playing an important par...

  2. The Effect of Daily Challenges in Children with Autism on Parents’ Couple Problem-Solving Interactions

    Science.gov (United States)

    Hartley, Sigan L.; Papp, Lauren M.; Blumenstock, Shari; Floyd, Frank; Goetz, Greta L.

    2016-01-01

    The vulnerability-stress-adaptation model guided this examination of the impact of daily fluctuations in the symptoms and co-occurring behavior problems of children with autism spectrum disorder (ASD) on parents’ couple problem-solving interactions in natural settings and as these interactions spontaneously occur. A 14-day daily diary was completed by mothers and fathers in 176 families who had a child with ASD. On each day of the diary, parents separately reported on the child with ASD's daily level of symptoms and co-occurring behavior problems and the topic and level of negative affect in their most meaningful or important daily couple problem-solving interaction. Multilevel modeling was used to account for the within-person, within-couple nested structure of the data. Results indicated that many parents are resilient to experiencing a day with a high level of child ASD symptoms and co-occurring behavior problems and do not report more negative couple problem-solving interactions. However, household income, level of parental broader autism phenotype, and presence of multiple children with special care needs served as vulnerability factors in that they were related to a higher overall rating of negative affect in couple interactions and moderated the impact of reporting a day with a high level of child ASD symptoms and co-occurring behavior problems on next-day ratings of negative couple problem-solving interactions. The magnitude of these effects was small. Understanding mechanisms that support adaptive couple interactions in parents of children with ASD is critical for promoting best outcomes. PMID:27336179

  3. Small Nations of Europe and the Modern Challenges: the Problem of Self-Identification

    Directory of Open Access Journals (Sweden)

    М А Егорова

    2009-06-01

    Full Text Available The article is devoted to the actual problem of regional separatism in European countries. The author suggests that now we can witness the rise of regional movements for independence all over the world. The problem of separatism of small nations of Europe sharpens after recognition of Kosovo's independence. The author proposes that establishment of common «European home» can wither destructive potential of separatist movements.

  4. After being challenged by a video game problem, sleep increases the chance to solve it.

    Directory of Open Access Journals (Sweden)

    Felipe Beijamini

    Full Text Available In the past years many studies have demonstrated the role of sleep on memory consolidation. It is known that sleeping after learning a declarative or non-declarative task, is better than remaining awake. Furthermore, there are reports of a possible role for dreams in consolidation of declarative memories. Other studies have reported the effect of naps on memory consolidation. With similar protocols, another set of studies indicated that sleep has a role in creativity and problem-solving. Here we hypothesised that sleep can increase the likelihood of solving problems. After struggling to solve a video game problem, subjects who took a nap (n = 14 were almost twice as likely to solve it when compared to the wake control group (n = 15. It is interesting to note that, in the nap group 9 out 14 subjects engaged in slow-wave sleep (SWS and all solved the problem. Surprisingly, we did not find a significant involvement of Rapid Eye Movement (REM sleep in this task. Slow-wave sleep is believed to be crucial for the transfer of memory-related information to the neocortex and implement intentions. Sleep can benefit problem-solving through the generalisation of newly encoded information and abstraction of the gist. In conclusion, our results indicate that sleep, even a nap, can potentiate the solution of problems that involve logical reasoning. Thus, sleep's function seems to go beyond memory consolidation to include managing of everyday-life events.

  5. After being challenged by a video game problem, sleep increases the chance to solve it.

    Science.gov (United States)

    Beijamini, Felipe; Pereira, Sofia Isabel Ribeiro; Cini, Felipe Augusto; Louzada, Fernando Mazzilli

    2014-01-01

    In the past years many studies have demonstrated the role of sleep on memory consolidation. It is known that sleeping after learning a declarative or non-declarative task, is better than remaining awake. Furthermore, there are reports of a possible role for dreams in consolidation of declarative memories. Other studies have reported the effect of naps on memory consolidation. With similar protocols, another set of studies indicated that sleep has a role in creativity and problem-solving. Here we hypothesised that sleep can increase the likelihood of solving problems. After struggling to solve a video game problem, subjects who took a nap (n = 14) were almost twice as likely to solve it when compared to the wake control group (n = 15). It is interesting to note that, in the nap group 9 out 14 subjects engaged in slow-wave sleep (SWS) and all solved the problem. Surprisingly, we did not find a significant involvement of Rapid Eye Movement (REM) sleep in this task. Slow-wave sleep is believed to be crucial for the transfer of memory-related information to the neocortex and implement intentions. Sleep can benefit problem-solving through the generalisation of newly encoded information and abstraction of the gist. In conclusion, our results indicate that sleep, even a nap, can potentiate the solution of problems that involve logical reasoning. Thus, sleep's function seems to go beyond memory consolidation to include managing of everyday-life events.

  6. Challenges Experienced by Korean Medical Students and Tutors during Problem-Based Learning: A Cultural Perspective

    Science.gov (United States)

    Ju, Hyunjung; Choi, Ikseon; Rhee, Byoung Doo; Tae-Lee, Jong

    2016-01-01

    How people learn is influenced by the cultural contexts in which their learning occurs. This qualitative case study explored challenges Korean medical students and tutors experienced during their PBL sessions from a cultural perspective using Hofstede's cultural dimensions. Twelve preclinical medical students and nine tutors from a large Korean…

  7. Exploring Cloud Computing Tools to Enhance Team-Based Problem Solving for Challenging Behavior

    Science.gov (United States)

    Johnson, LeAnne D.

    2017-01-01

    Data-driven decision making is central to improving success of children. Actualizing the use of data is challenging when addressing the social, emotional, and behavioral needs of children across different types of early childhood programs (i.e., early childhood special education, early childhood family education, Head Start, and childcare).…

  8. Scientific and Technical Challenges in Thermal Transport and Thermoelectric Materials and Devices

    KAUST Repository

    O'Dwyer, Colm

    2017-01-19

    This paper considers the state-of-the-art and open scientific and technological questions in thermoelectric materials and devices, from phonon engineering and scattering methods, to new and complex materials and their thermoelectric behavior. The paper also describes recent approaches to create structural and compositional material systems designed to enhance the thermoelectric figure of merit and power factors. We also summarize and contextualize recent advances in the use of superlattice structures and porosity or roughness to influence phonon scattering mechanisms and detail some advances in integrated thermoelectric materials for generators and coolers for thermally stable photonic devices.

  9. Scientific and Technical Challenges in Thermal Transport and Thermoelectric Materials and Devices

    KAUST Repository

    O'Dwyer, Colm; Chen, Renkun; He, Jr-Hau; Lee, Jaeho; Razeeb, Kafil M.

    2017-01-01

    This paper considers the state-of-the-art and open scientific and technological questions in thermoelectric materials and devices, from phonon engineering and scattering methods, to new and complex materials and their thermoelectric behavior. The paper also describes recent approaches to create structural and compositional material systems designed to enhance the thermoelectric figure of merit and power factors. We also summarize and contextualize recent advances in the use of superlattice structures and porosity or roughness to influence phonon scattering mechanisms and detail some advances in integrated thermoelectric materials for generators and coolers for thermally stable photonic devices.

  10. An Algorithmic Comparison of the Hyper-Reduction and the Discrete Empirical Interpolation Method for a Nonlinear Thermal Problem

    Directory of Open Access Journals (Sweden)

    Felix Fritzen

    2018-02-01

    Full Text Available A novel algorithmic discussion of the methodological and numerical differences of competing parametric model reduction techniques for nonlinear problems is presented. First, the Galerkin reduced basis (RB formulation is presented, which fails at providing significant gains with respect to the computational efficiency for nonlinear problems. Renowned methods for the reduction of the computing time of nonlinear reduced order models are the Hyper-Reduction and the (Discrete Empirical Interpolation Method (EIM, DEIM. An algorithmic description and a methodological comparison of both methods are provided. The accuracy of the predictions of the hyper-reduced model and the (DEIM in comparison to the Galerkin RB is investigated. All three approaches are applied to a simple uncertainty quantification of a planar nonlinear thermal conduction problem. The results are compared to computationally intense finite element simulations.

  11. The promise and challenges of cermet fueled nuclear thermal propulsion reactors

    International Nuclear Information System (INIS)

    Brengle, R.G.; Harty, R.B.; Bhattacharyya, S.K.

    1993-06-01

    The use of cermet fuels in nuclear thermal propulsion systems was examined and the characteristics of systems using these fuel forms is discussed in terms of current mission and safety requirements. For use at high temperatures cermet fueled reactors utilize ceramic fuels with refractory metals as the matrix material. Cermet fueled reactors tend to be heavy when compared to concepts that utilize graphite as the fuel matrix because of the high density of the refractory metal matrix which makes up 20-40 percent of the total volume. On the positive side the metal matrix is strong and more resistant to loads from either the launch or flow induced vibration. The compatibility of the tungsten cermet with hydrogen is excellent and lifetimes of several hours is certainly achievable. Probably the biggest drawback to cermet nuclear thermal propulsion concepts is that the amount of actual data to support the theoretical conclusions is small. In fact there is no data under representative conditions of temperature, propellant and flux for the required fuel burnup. Although cermet systems appear to be attractive, the lack of fuel data at representative conditions does not allow reliable comparisons of cermet systems to systems where fuel data is available. 10 refs

  12. Nanofluid two-phase flow and thermal physics: a new research frontier of nanotechnology and its challenges.

    Science.gov (United States)

    Cheng, Lixin; Bandarra Filho, Enio P; Thome, John R

    2008-07-01

    Nanofluids are a new class of fluids engineered by dispersing nanometer-size solid particles in base fluids. As a new research frontier, nanofluid two-phase flow and thermal physics have the potential to improve heat transfer and energy efficiency in thermal management systems for many applications, such as microelectronics, power electronics, transportation, nuclear engineering, heat pipes, refrigeration, air-conditioning and heat pump systems. So far, the study of nanofluid two-phase flow and thermal physics is still in its infancy. This field of research provides many opportunities to study new frontiers but also poses great challenges. To summarize the current status of research in this newly developing interdisciplinary field and to identify the future research needs as well, this paper focuses on presenting a comprehensive review of nucleate pool boiling, flow boiling, critical heat flux, condensation and two-phase flow of nanofluids. Even for the limited studies done so far, there are some controversies. Conclusions and contradictions on the available nanofluid studies on physical properties, two-phase flow, heat transfer and critical heat flux (CHF) are presented. Based on a comprehensive analysis, it has been realized that the physical properties of nanofluids such as surface tension, liquid thermal conductivity, viscosity and density have significant effects on the nanofluid two-phase flow and heat transfer characteristics but the lack of the accurate knowledge of these physical properties has greatly limited the study in this interdisciplinary field. Therefore, effort should be made to contribute to the physical property database of nanofluids as a first priority. Secondly, in particular, research on nanofluid two-phase flow and heat transfer in microchannels should be emphasized in the future.

  13. Petroleum industry's current progress and challenges in dealing with the year 2000 problem

    International Nuclear Information System (INIS)

    Kraus, D.I.; Radu, C.G.; McKenzie, S.; Stuart, K.

    1998-01-01

    The steps that some major oil companies in Canada have taken to prepare their computers and automated equipment for the year 2000 (Y2K) are described. It is acknowledged that with 1700 retail service stations, over 300 wholesale operations, and 26 terminals, the extent of the problem is great. In addition some 38 upstream and 65 downstream applications have been identified as mission critical, not counting the 30 mission critical control systems in the upstream field operations and approximately the same number of operations in the downstream refinery. The good news is that remediation and testing is well underway nationally and the Calgary test laboratory will be commercially available in 1999. Getting management on-side, selling the positive aspects of Y2K, making good use of reputable consulting companies, keeping employees properly informed of problems and progress, are some of the key criteria in solving Y2K problems successfully

  14. Climate is the real challenge, not shortage. New problems arising for global energy supply

    Energy Technology Data Exchange (ETDEWEB)

    Pestel, E.

    1988-11-01

    The author of the article is Professor E. Pestel who, as an executive member of the Club of Rome, belongs to the group of experts who first gave impetus to start thinking about the global problems of mankind. In his publications on the problems linked with CO/sub 2/ emission he explains the unavoidable dilemma created by the growing world population and the growing demand for energy on the one hand, and the resulting hazards to the global climate on the other. His analyses take away the soft cushion of hopeful make-believe still widespread in the Western World, and in his capacity as an expert and realist he decidedly calls for decisions and measures to tackle the problem.

  15. Biopiracy after the Nagoya Protocol: Problem Structure, Regime Design and Implementation Challenges

    Directory of Open Access Journals (Sweden)

    Florian Rabitz

    2015-08-01

    Full Text Available This article assesses the effectiveness of the 2010 Nagoya Protocol to the Convention on Biological Diversity (CBD for addressing "biopiracy" of genetic resources; that is, their biotechnological utilization in violation of either the provider country legislation or mutually agreed contractual obligations. Biopiracy is defined as a problem resulting from a distributive conflict between provider and user countries, the practical difficulties of monitoring the utilization of genetic resources in a transnational context, and the pervasive scientific uncertainty about the nature and extent of the problem. The Nagoya Protocol predominantly focuses on compliance management while lacking the necessary enforcement provisions for deterring non-compliance through effective monitoring and sanctions. Using the example of recent European Union implementing legislation, this article underscores how parties may use the Protocol's legal ambiguities to soften its regulatory impact on domestic industry. As a result, in light of both problem structure and regime design, the Protocol only offers modest improvements over the status quo ante.

  16. Some computational challenges of developing efficient parallel algorithms for data-dependent computations in thermal-hydraulics supercomputer applications

    International Nuclear Information System (INIS)

    Woodruff, S.B.

    1992-01-01

    The Transient Reactor Analysis Code (TRAC), which features a two- fluid treatment of thermal-hydraulics, is designed to model transients in water reactors and related facilities. One of the major computational costs associated with TRAC and similar codes is calculating constitutive coefficients. Although the formulations for these coefficients are local the costs are flow-regime- or data-dependent; i.e., the computations needed for a given spatial node often vary widely as a function of time. Consequently, poor load balancing will degrade efficiency on either vector or data parallel architectures when the data are organized according to spatial location. Unfortunately, a general automatic solution to the load-balancing problem associated with data-dependent computations is not yet available for massively parallel architectures. This document discusses why developers algorithms, such as a neural net representation, that do not exhibit algorithms, such as a neural net representation, that do not exhibit load-balancing problems

  17. The Criterion A problem revisited: controversies and challenges in defining and measuring psychological trauma.

    Science.gov (United States)

    Weathers, Frank W; Keane, Terence M

    2007-04-01

    The Criterion A problem in the field of traumatic stress refers to the stressor criterion for posttraumatic stress disorder (PTSD) and involves a number of fundamental issues regarding the definition and measurement of psychological trauma. These issues first emerged with the introduction of PTSD as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III; American Psychiatric Association, 1980) and continue to generate considerable controversy. In this article, the authors provide an update on the Criterion A problem, with particular emphasis on the evolution of the DSM definition of the stressor criterion and the ongoing debate regarding broad versus narrow conceptualizations of traumatic events.

  18. New challenge for the Norwegian electric power market: A free market of power creates stability problems

    International Nuclear Information System (INIS)

    Gjengedal, T.; Rabbe, O.; Ongstad, E.; Uhlen, K.; Hauger, B.; Vormedal, L.; Lysheim, D.

    1997-01-01

    The article relates to problems of grid stability as a consequence of market-based power turnover. In combination with special hydrologic conditions, new approaches are formed concerning power production and transmission. Efficient counter-acting efforts must be initiated at an early stage for power system stabilization also concerning future innovations from the year of 2000. Examples on the development of systems of static magnetization and damping, problems concerning dampers, power grid testing, digital regulators, faults in high voltage 3-phase systems, and evaluation of measures of improvement are discussed. 10 figs

  19. Are project managers ready for the 21th challenges? A review of problem structuring methods for decision support

    Directory of Open Access Journals (Sweden)

    José Mateo

    2017-01-01

    Full Text Available Numerous contemporary problems that project managers face today can be considered as unstructured decision problems characterized by multiple actors and perspectives, incommensurable and/or conflicting objectives, and important intangibles. This work environment demands that project managers possess not only hard skills but also soft skills with the ability to take a management perspective and, above all, develop real leadership capabilities. In this paper, a family of problem structured methods for decision support aimed at assisting project managers in tackling complex problems are presented. Problem structured methods are a family of soft operations research methods for decision support that assist groups of diverse composition to agree a problem focus and make commitments to consequential action. Project management programs are challenged to implement these methodologies in such a way that it is organized around the key competences that a project manager needs in order to be more effective, work efficiently as members of interdisciplinary teams and successfully execute even a small project.

  20. PROBLEMS OF FORMATION OF HIGHLY QUALIFIED SPECIALIST IN ACCORDANCE WITH FUNDAMENTALLY NEW CHALLENGES OF MODERNITY

    Directory of Open Access Journals (Sweden)

    Vladimir Shostka

    2015-09-01

    Full Text Available Some aspects of education of specialists are reflected in the article. Methods and problems of organization of improvement of quality and efficiency of learning process are considered. The paper conducts a comparative analysis of the competencies that are formed at different levels of education according to Russian and European educational standards.

  1. Challenging Childhoods: Young People's Accounts of "Getting By" in Families with Substance Use Problems

    Science.gov (United States)

    Backett-Milburn, Kathryn; Wilson, Sarah; Bancroft, Angus; Cunningham-Burley, Sarah

    2008-01-01

    Concern is increasing about children growing up in families where there are substance use problems but relatively little is known about the perspectives of the children themselves. This article reports on a qualitative study with young people who grew up in such families, exploring their accounts of their daily lives at home, school and leisure.…

  2. Status Problem and Expectations of Competence: A Challenging Path for Teachers

    Science.gov (United States)

    Pescarmona, Isabella

    2015-01-01

    Complex Instruction (CI) is a cooperative learning approach, which aims at improving the equal status interaction among students working in groups who may be at different academic and social levels. Based on an ethnographic research, the article examines how a group of Italian primary school teachers understand the status problem and how the…

  3. The Shape of a Sausage: A Challenging Problem in the Calculus of Variations

    Science.gov (United States)

    Deakin, Michael A. B.

    2010-01-01

    Many familiar household objects (such as sausages) involve the maximization of a volume under geometric constraints. A flexible but inextensible membrane bounds a volume which is to be filled to capacity. In the case of the sausage, a full analytic solution is here provided. Other related but more difficult problems seem to demand approximate…

  4. Rethinking the globalisation of problem-based learning: how culture challenges self-directed learning.

    NARCIS (Netherlands)

    Frambach, J.M.; Driessen, E.W.; Chan, L.C.; Vleuten, C.P.M. van der

    2012-01-01

    Medical Education 2012: 46: 738-747 Context Medical schools worldwide are increasingly switching to student-centred methods such as problem-based learning (PBL) to foster lifelong self-directed learning (SDL). The cross-cultural applicability of these methods has been questioned because of their

  5. Advancing the "Colorado Graduates" Agenda: Understanding the Dropout Problem and Mobilizing to Meet the Graduation Challenge

    Science.gov (United States)

    Mac Iver, Martha Abele; Balfanz, Robert; Byrnes, Vaughan

    2009-01-01

    The ambitious goal set by Colorado's governor to address the state's dropout problem is a model for the nation. Helping thousands of young people to receive their high school diplomas instead of leaving school without them is a crucial step in improving the quality of life for all Colorado residents. Accomplishing this goal will require focused…

  6. Problems and challenges in care for children undergoing radiotherapy- A research paper

    International Nuclear Information System (INIS)

    Mucheusi, L.

    2006-01-01

    for children undergoing radiotherapy and their parents, a paediatric radiographer may be one welcome solution to relieve the anxiety and stress during this difficult time in their lives. given the various factors, no one solution can be deemed ultimate in dealing with this complex situation. thus further efforts are needed to bring about workable solutions to this problem depending on the circumstances and situation

  7. Thermal use of challenging biomass fuels; Thermische Nutzung von anspruchsvollen Biomassebrennstoffen. Versuche Herbst 2006

    Energy Technology Data Exchange (ETDEWEB)

    Buehler, R. [Umwelt und Energie, Maschwanden (Switzerland); Hersener, J.-L. [Ingenieurbuero Hersener, Wiesendangen (Switzerland); Jenni, A. [Ardens GmbH, Liestal (Switzerland); Klippel, N. [Verenum, Zuerich (Switzerland)

    2007-10-15

    This final report for the Swiss Federal Office of Energy (SFOE) reports on experiments made in autumn 2006 on the thermal use of biomass fuels such as agricultural wastes. As a continuation of the tests performed in 2005, further tests were planned for 2006. The authors quote that for various reasons, only part of the planned test program could be carried out. Tests made with the fuel mixtures sedge and chipped wood as well as horse manure, sedge and chipped wood are reported on. The tests showed that, under optimal conditions, these fuel mixtures can be used as biomass fuel, leading to low emissions. Stable combustion conditions were, however, very difficult to achieve. Details on the tests performed and their results are presented and knowledge gained is discussed.

  8. Modeling Thermally Driven Flow Problems with a Grid-Free Vortex Filament Scheme: Part 1

    Science.gov (United States)

    2018-02-01

    simulation FMM Fast Multipole Method GPUs graphic processing units LES Large Eddy Simulation M-O Monin-Obukhov MPI Message Passing Interface Re Reynolds...mail.mil>. Grid-free representation of turbulent flow via vortex filaments offers a means for large eddy simulations that faithfully and efficiently...particle, Lagrangian, turbulence, grid-free, large eddy simulation , natural convection, thermal bubble 56 Pat Collins 301-394-5617Unclassified

  9. Sumudu transform series expansion method for solving the local fractional Laplace equation in fractal thermal problems

    Directory of Open Access Journals (Sweden)

    Guo Zheng-Hong

    2016-01-01

    Full Text Available In this article, the Sumudu transform series expansion method is used to handle the local fractional Laplace equation arising in the steady fractal heat-transfer problem via local fractional calculus.

  10. Problem solving and intercultural dynamics in a PBL context: Challenges and solutions

    DEFF Research Database (Denmark)

    Brambini-Pedersen, Jan Vang; Brambini, Annalisa; Prætorius, Thim

    2018-01-01

    Recent years has witnessed an increased internationalization of universities including AAU Copenhagen’s study programs where 25% of the students are Non-Danish. This provides new opportunities and challenges for the students and teachers. This survey investigates if Danish and non-Danish students...... impact the forming phase negatively, which in turn increases the risk for intercultural conflicts. The student survey also indicates that group supervisors might be too task focused and that they need to pay more attention to group and intercultural dynamics. For developing the PBL model further...

  11. Single pin BWR benchmark problem for coupled Monte Carlo - Thermal hydraulics analysis

    International Nuclear Information System (INIS)

    Ivanov, A.; Sanchez, V.; Hoogenboom, J. E.

    2012-01-01

    As part of the European NURISP research project, a single pin BWR benchmark problem was defined. The aim of this initiative is to test the coupling strategies between Monte Carlo and subchannel codes developed by different project participants. In this paper the results obtained by the Delft Univ. of Technology and Karlsruhe Inst. of Technology will be presented. The benchmark problem was simulated with the following coupled codes: TRIPOLI-SUBCHANFLOW, MCNP-FLICA, MCNP-SUBCHANFLOW, and KENO-SUBCHANFLOW. (authors)

  12. Single pin BWR benchmark problem for coupled Monte Carlo - Thermal hydraulics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, A.; Sanchez, V. [Karlsruhe Inst. of Technology, Inst. for Neutron Physics and Reactor Technology, Herman-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Hoogenboom, J. E. [Delft Univ. of Technology, Faculty of Applied Sciences, Mekelweg 15, 2629 JB Delft (Netherlands)

    2012-07-01

    As part of the European NURISP research project, a single pin BWR benchmark problem was defined. The aim of this initiative is to test the coupling strategies between Monte Carlo and subchannel codes developed by different project participants. In this paper the results obtained by the Delft Univ. of Technology and Karlsruhe Inst. of Technology will be presented. The benchmark problem was simulated with the following coupled codes: TRIPOLI-SUBCHANFLOW, MCNP-FLICA, MCNP-SUBCHANFLOW, and KENO-SUBCHANFLOW. (authors)

  13. Challenges, problems and possible solutions in wind generator systems from the aspect of forecast, planning and delivery of wind energy

    International Nuclear Information System (INIS)

    Giovski, Nikola

    2014-01-01

    The fundamental difficulties of integrating wind energy into the power system arise from its large temporal variability and limited predictability. That's why the integration of wind power presents major challenge for today's operating and planning practices of the power system operators. Accurate predictions of the possible wind power output, in time intervals relevant for creating schedules for production and exchange capacity, allows to system operators and dispatching personnel more efficient power system management. Despite the challenges and problems that arise due to integration of wind power into power systems, which need to be solved or reduced, wind power has its advantages that should be utilized. The effective integration of wind power plants into the transmission grid should allow them to represent the backbone of future energy systems. Modern wind generators represent production units that have the ability to participate in the management of energy systems e.g. in the regulation of frequency, voltage and other network operating requirements. This paper provides a brief overview of global experiences with the challenges, problems and possible solutions that appear in wind generator systems from the aspect of forecasting, planning and delivery of wind energy. (author)

  14. Hate Speech Detection: A Solved Problem? The Challenging Case of Long Tail on Twitter

    OpenAIRE

    Zhang, Ziqi; Luo, Lei

    2018-01-01

    In recent years, the increasing propagation of hate speech on social media and the urgent need for effective counter-measures have drawn significant investment from governments, companies, and empirical research. Despite a large number of emerging, scientific studies to address the problem, the performance of existing automated methods at identifying specific types of hate speech - as opposed to identifying non-hate -is still very unsatisfactory, and the reasons behind are poorly understood. ...

  15. Problems and Challenges in Human Resource Management: Case of a Large Organization in Pakistan

    Directory of Open Access Journals (Sweden)

    Ali Irshad

    2008-09-01

    Full Text Available This paper critically analyzes the work culture for a mainstream financial organization operating within Pakistan, while drawing a specific example to elucidate certain dilemmas that impede the potential growth for the financial sector and its constituent workforce, besides hampering the performance of the organizations. The case study is related to an organization in financial sector which conducts a Management Trainee Program with the purpose to select, train and develop a high-potential pool of talent into future leaders and fore-runners of the organization. This paper critically analyzes several inherent problems that face the successful implementation of the trainee program under the frameworks of various theories of organizational management. To solve these problems, this article presents a detailed diagnosis of the management shortcomings to improve the firm‟s corporate culture, work ethics and employee handling strategy and mechanism. Recommendations are also made to minimize the problems and maximize the success of the Management Trainee Program in the case study organization.

  16. Diagnosis of tuberculosis in camelids: old problems, current solutions and future challenges.

    Science.gov (United States)

    Alvarez, J; Bezos, J; Juan, L de; Vordermeier, M; Rodriguez, S; Fernandez-de-Mera, I G; Mateos, A; Domínguez, L

    2012-02-01

    In spite of great efforts for its control and eradication, tuberculosis remains one of the most important zoonosis worldwide. Its causative agents, the members of the Mycobacterium tuberculosis complex, have a wide host range that complicates the epidemiology of this disease. Among susceptible species to these pathogens, camelids from the New World (llama, alpaca and vicuña) and Old World (Bactrian camel and dromedary) are acquiring an increasing importance in several European countries because of its growing number and could act as reservoirs of the disease for livestock and humans in their natural habitat. In addition, tuberculosis caused by a number of M. tuberculosis complex members is a life-threatening disease in these animal species. Although tuberculosis has been known to affect camelids for a long time, ante-mortem diagnosis is still challenging because of the lack of standardized diagnostic techniques and the limited sensitivity and specificity of the most widely applied tests. However, in recent years, several techniques that can at least partially overcome these limitations have been developed. This paper reviews the results and advances achieved in tuberculosis diagnosis in camelids in the last decade as well as the progresses on ongoing investigations, with special attention to the remaining challenges that still have to be faced to assure the availability of reliable tools for the detection of tuberculosis-infected animals and herds. © 2011 Blackwell Verlag GmbH.

  17. Scaling of Thermal Images at Different Spatial Resolution: The Mixed Pixel Problem

    Directory of Open Access Journals (Sweden)

    Hamlyn G. Jones

    2014-07-01

    Full Text Available The consequences of changes in spatial resolution for application of thermal imagery in plant phenotyping in the field are discussed. Where image pixels are significantly smaller than the objects of interest (e.g., leaves, accurate estimates of leaf temperature are possible, but when pixels reach the same scale or larger than the objects of interest, the observed temperatures become significantly biased by the background temperature as a result of the presence of mixed pixels. Approaches to the estimation of the true leaf temperature that apply both at the whole-pixel level and at the sub-pixel level are reviewed and discussed.

  18. Additional Insights Into Problem Definition and Positioning From Social Science Comment on "Four Challenges That Global Health Networks Face".

    Science.gov (United States)

    Quissell, Kathryn

    2017-09-10

    Commenting on a recent editorial in this journal which presented four challenges global health networks will have to tackle to be effective, this essay discusses why this type of analysis is important for global health scholars and practitioners, and why it is worth understanding and critically engaging with the complexities behind these challenges. Focusing on the topics of problem definition and positioning, I outline additional insights from social science theory to demonstrate how networks and network researchers can evaluate these processes, and how these processes contribute to better organizing, advocacy, and public health outcomes. This essay also raises multiple questions regarding these processes for future research. © 2018 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

  19. Current challenges and problems in teaching pathophysiology in Ukraine - another reaction to Churilov's paper.

    Science.gov (United States)

    Ataman, Oleksandr V

    2017-12-01

    Pathophysiology in Ukraine has rich traditions and achievements in the scientific areas, as well as in teaching academic discipline. Its history, the main Ukrainian scientific schools and their famous representatives are briefly described. The content of existing study program, the main approaches to teaching, and some methodological and organizational problems needed to be solved are characterized. The necessity and usefulness of developing and implementing the three separate courses of discipline (Essential, Clinical and Advanced Pathophysiology) are substantiated. The place of Pathophysiology in the training of physicians with different kinds of their future activity is discussed. Relation of teaching Pathophysiology to Translational and Personalized Medicine is tried to be shown.

  20. Reflections on foreign language study for students with language learning problems: research, issues and challenges.

    Science.gov (United States)

    Ganschow, L; Sparks, R L

    2000-01-01

    The study of foreign language (FL) learning for individuals who have found learning to read and write in their first language extremely problematic has been an under-researched area throughout the world. Since the 1980s, Leonore Ganschow and Richard Sparks have conducted pioneering research into the nature of difficulties, why they are encountered and how they can be minimized. In this paper the authors trace the development of their research on foreign language difficulties for students with language learning problems. They provide a summary of their findings and suggest new questions and directions for the field.

  1. Black boxes on wheels: research challenges and ethical problems in MEA-based robotics

    DEFF Research Database (Denmark)

    Bentzen, Martin Mose

    2016-01-01

    Robotic systems consisting of a neuron culture grown on a multielectrode array (MEA) which is connected to a virtual or mechanical robot have been studied for approximately 15 years. It is hoped that these MEA-based robots will be able to address the problem that robots based on conventional...... and that they are not likely to be solved within the field. After that, I discuss whether MEA-based robotics should be considered pop science. Finally, I investigate the ethical aspects of this research....

  2. Construction of anthropological knowledge and ethnographic co-research. Problems and challenges

    Directory of Open Access Journals (Sweden)

    Elena L. Achilli

    2017-09-01

    Full Text Available Discussing anthropological knowledge construction processes entails reflecting upon different connected dimensions. Epistemological and theoretical-methodological  positionings with different political consequences are intertwined. In addition, institutional conditions and the socio-historical context in which certain local and global disciplinary trends are inscribed must be taken into account. This paper looks into the processes of socio-anthropological research I have participated in over the last decades with schools, teachers, teacher unions, indigenous peoples and groups in conditions of structural poverty. I will particularly focus on the modalities of ethnographic co-research that we have implemented in several projects. I will attempt to show some of the theoretical-methodological potentialities that ethnography contributes to group/collective processes of research as well as limits in its development. Finally, I will mention some of the contemporary challenges anthropological knowledge faces in present Latin America.

  3. Effects of GnRHa treatment during vitellogenesis on the reproductive physiology of thermally challenged female Atlantic salmon (Salmo salar

    Directory of Open Access Journals (Sweden)

    Kelli Anderson

    2017-10-01

    Full Text Available Tasmanian Atlantic salmon (S. salar broodstock can experience temperatures above 20 °C, which impairs reproductive development and inhibits ovulation. The present study investigated the prolonged use of gonadotropin releasing hormone analogue (GnRHa during vitellogenesis as a means of maintaining endocrine function and promoting egg quality at elevated temperature in maiden and repeat spawning S. salar. GnRHa-treatment during vitellogenesis did not compensate for the negative effects of thermal challenge on the timing of ovulation, egg size, egg fertility or embryo survival in any fish maintained at 22 °C relative to 14 °C. The lack of effectiveness was reflected by the endocrine data, as plasma follicle stimulating hormone and luteinising hormone levels were not different between treated and untreated groups at 22 °C. Furthermore, plasma testosterone and E2 levels were unchanged in GnRHa-treated fish at 22 °C, and plasma levels were generally lower in both groups maintained at 22 °C relative to 14 °C. Transcription of vitellogenin, and zona pellucida B and C was not enhanced in GnRHa-treated fish relative to untreated fish at 22 °C, presumably due to observed suppression of plasma E2. These results indicate that thermal impairment of reproduction is likely to occur on multiple levels, and is difficult to overcome via hormonal manipulation.

  4. A frictional contact problem with wear involving elastic-viscoplastic materials with damage and thermal effects

    Directory of Open Access Journals (Sweden)

    Abdelmoumene Djabi

    2015-05-01

    Full Text Available We consider a mathematical problem for quasistatic contact between a thermo-elastic-viscoplastic body with damage and an obstacle. The contact is frictional and bilateral with a moving rigid foundation which results in the wear of the contacting surface. We employ the thermo-elasticviscoplastic with damage constitutive law for the material. The damage of the material caused by elastic deformations. The evolution of the damage is described by an inclusion of parabolic type. The problem is formulated as a coupled system of an elliptic variational inequality for the displacement, a parabolic variational inequality for the damage and the heat equation for the temperature. We establish a variational formulation for the model and we prove the existence of a unique weak solution to the problem. The proof is based on a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  5. A novel challenge test incorporating irradiation (60Co) of compost sub-samples to validate thermal lethality towards pathogenic bacteria.

    Science.gov (United States)

    Moore, John E; Watabe, Miyuki; Stewart, Andrew; Cherie Millar, B; Rao, Juluri R

    2009-01-01

    Maturing compost heaps normally attaining temperatures ranging from 55 to 65 degrees C is generally regarded to conform to recommended biological risks and sanitation standards for composts stipulated by either EU or US-EPA. Composted products derived from animal sources are further required by EU biohazard safety regulatory legislation that such composts either attain 70 degrees C for over 3h during maturation or via treatment at 70 degrees C for 1h before being considered for dispensation on land. The setting of the upper limit of thermal lethality at 70 degrees C/1h for achieving biosecurity of the animal waste composted products (e.g. pelleted fertilizer formulations) is not properly substantiated by specific validation tests, comprising a 'wipe-out' step (usually via autoclaving) followed by inoculation of a prescribed bacterium, exposure to 70 degrees C/1h and the lethality determined. Pelleted formulations of composts are not amenable for wet methods (autoclaving) for wipe-out sterilization step as this is detrimental to the pellet and compromises sample integrity. This study describes a laboratory method involving the employment of ((60)Co) irradiation 'wipe-out' step to: (a) compost sub-samples drawn from compost formulation heaps and (b) pelleted products derived from composted animal products while determining the thermal lethality of a given time/temperature (70 degrees C/1h) treatment process and by challenging the irradiated sample (not just with one bacterium but), out with 10 potential food-poisoning organisms from the bacterial genera (Campylobacter, Escherichia, Listeria, Salmonella, Yersinia) frequently detected in pig and poultry farm wastes. This challenge test on compost sub-samples can be a useful intervention ploy for 'inspection and validation' technique for composters during the compost maturity process, whose attainment of temperatures of 55-65 degrees C is presumed sufficient for attainment of sanitation. Stringent measures are further

  6. Pressure sores--a constant problem for plegic patients and a permanent challenge for plastic surgery.

    Science.gov (United States)

    Giuglea, Carmen; Marinescu, Sllviu; Florescu, Ioan Petre; Jecan, Crenguta

    2010-01-01

    Pressure sores can be defined as lesions caused by unrelieved pressure resulting in damage of the underlying tissue. They represent a common problem in the pathology of plegic patients and, plastic surgery has a significant role in their treatment. Pressure sores occur over bony prominences and so, they are most commonly seen at the sacrum and trochanters in paralyzed patients and at ischium for the patients who sit in a wheelchair for a long time. For these patients, surgical treatment is very important because on one hand, it stops the loss of nutrients and proteins at the site of the pressure sore, and on the other hand, it permits the initiation of neuromuscular recuperation treatment much faster.

  7. English as Medium of Instruction in Economic University Education: Problems and Challenges

    Directory of Open Access Journals (Sweden)

    Anna Y. Polenova

    2016-09-01

    Full Text Available The paper attempts to analyze several approaches to learning a foreign language based on using English as Medium of Instruction (EMI in High School. Special attention is given to the «content and language integrated learning» (CLIL as the most progressive approach to defining the scope of professional education. The author classifies the models of language teaching within the statedapproaches that promote the efficiency of professional training of future economists in solving professional problems on the basis of implementation of foreign language competence. The paper defines the conditions of subject and language integrated models implementation into the learning process. In conclusion, it is noted that the integration of subject and language experience contributes to the optimization of foreign language training and a significant improvement in the quality of the educational process.

  8. International standard problem ISP-47 on containment thermal hydraulics - Final report

    International Nuclear Information System (INIS)

    Allelein, H. J.; Schwarz, S.; Fischer, K.; Vendel, J.; Malet, J.; Bentaib, A.; Studer, E.; Paillere, H.; Houkema, M.

    2007-01-01

    The main objective of the ISP-47 is to assess the capabilities of Lumped Parameter (LP) and Computational Fluid Dynamics (CFD) codes in the area of containment thermal-hydraulics. Following the recommendations made in the state-of-the-art report on 'Containment Thermal-hydraulics and Hydrogen Distribution' this ISP was based on the application of different complementary experimental facilities and a progressive modelling difficulty. The three experimental facilities TOSQAN, MISTRA and ThAI have shown the quality of the provided experimental data suitable for CFD and LP code benchmarking in steady-state and transient conditions (control of the initial and boundary conditions, and the accuracy of the measurement techniques). This mainly includes pressure transients and gas temperature field as in former exercises. Detailed gas velocity and gas concentration (air, steam and helium) fields were obtained for the first time in such an exercise. ISP-47 was executed in two main steps: Step 1 was dedicated to the validation of the codes in the separate effects facility TOSQAN (7 m 3 ). Wall condensation, steam injection in air or air / helium atmospheres, and buoyancy were addressed under well-controlled initial conditions in a simple geometry. Furthermore, the interactions of phenomena such as condensation / stratification, turbulence / buoyancy, etc. were addressed using the larger scale of MISTRA (100 m 3 ) facility. Both TOSQAN and MISTRA were specifically designed to produce data for CFD codes with state-of-the-art instrumentation. The TOSQAN benchmark was open, whereas the MISTRA benchmark was blind. Step 2 addressed the code assessment using an experiment in the multi-compartment ThAI (60 m 3 ) facility with different steam and helium injection phases, transient stratification and mixing conditions in the atmosphere, development of natural convection, wall condensate distribution, fog formation, and transient thermal response of heat conducting walls. Detailed

  9. A parallel multi-domain solution methodology applied to nonlinear thermal transport problems in nuclear fuel pins

    Energy Technology Data Exchange (ETDEWEB)

    Philip, Bobby, E-mail: philipb@ornl.gov [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Berrill, Mark A.; Allu, Srikanth; Hamilton, Steven P.; Sampath, Rahul S.; Clarno, Kevin T. [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Dilts, Gary A. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545 (United States)

    2015-04-01

    This paper describes an efficient and nonlinearly consistent parallel solution methodology for solving coupled nonlinear thermal transport problems that occur in nuclear reactor applications over hundreds of individual 3D physical subdomains. Efficiency is obtained by leveraging knowledge of the physical domains, the physics on individual domains, and the couplings between them for preconditioning within a Jacobian Free Newton Krylov method. Details of the computational infrastructure that enabled this work, namely the open source Advanced Multi-Physics (AMP) package developed by the authors is described. Details of verification and validation experiments, and parallel performance analysis in weak and strong scaling studies demonstrating the achieved efficiency of the algorithm are presented. Furthermore, numerical experiments demonstrate that the preconditioner developed is independent of the number of fuel subdomains in a fuel rod, which is particularly important when simulating different types of fuel rods. Finally, we demonstrate the power of the coupling methodology by considering problems with couplings between surface and volume physics and coupling of nonlinear thermal transport in fuel rods to an external radiation transport code.

  10. “It's Your Problem. Deal with It.” Performers' Experiences of Psychological Challenges in Music

    Directory of Open Access Journals (Sweden)

    Ellis Pecen

    2018-01-01

    Full Text Available Musicians need to deal with a range of challenges during their performance career and in response to these have reported a number of conditions that impact on their performance. Although social support from peers and teachers has been identified as part of the process of dealing with these challenges, little is understood about musicians' coping methods, beliefs and their attitudes toward support. Therefore, this study aimed to explore (a performers' previous experiences of psychological challenges, (b the types of support they used and, (c how this might inform future support programs in learning environments. Fifteen interviews were conducted with pre-elite (n = 5 transitioning elite (n = 3 and established elite performers (n = 7 in order to elicit data on psychological challenges, coping, beliefs and preferences for support. Inductive content analysis suggested that elite performers in this sample reported positive health habits, philosophical views of performance, health and life, positive anxiety reappraisal, and use of various psychological strategies, albeit without being explicitly aware of it. The need for various professional skills (e.g., communication, business, self-management, and organizational skills was emphasized by all participants. Transition into conservatoire was marked by severe psychological challenges, disorders and trauma. Primary sources of support included friends, family and self-help literature. Professional help was predominantly sought for physical problems. The impact of teachers was paramount, yet securing good teachers was considered a matter of “luck.” The most negative aspects recounted included abusive teachers, unsupportive environments, social comparison, competition, and disillusionment after entering the profession. Participants believed that talent could be developed and also valued wellbeing in relation to performance. Positive effects of late specialization on social development and professional

  11. Technological incorporation in the Unified Health System (SUS: the problem and ensuing challenges

    Directory of Open Access Journals (Sweden)

    Reinaldo Guimarães

    2014-12-01

    Full Text Available Technological incorporation is a central topic among the concerns regarding health care systems. This paper discusses the role of technology dynamics in health systems' cost increases, suggesting two different approaches - a 'pragmatic-economic' approach and a 'rational-defensive' approach - as guidelines to explain the reasons for this centrality. The paper shows how judicialization results from this situation and discusses two doctrinal views - 'reserve for contingencies' and 'rational use' - as the views that usually guide the debates in the courts and among health policy makers. The paper suggests that the attitude currently prevalent in the Brazilian judiciary system can prejudice the principle of equity by improperly evaluating the principle of integrality. We present a brief genealogy of HTA and a timeline of HTA in Brazil. We also discuss the relevance and the impact of Law 12401/2011, which regulates the principle of integrality in the Unified Health System (SUS and propose three challenges to the development of HTA actions aiming at technology incorporation in Brazil. Finally, we discuss the entry and the role of private health insurance companies, emphasizing changes in the scenario and in their position.

  12. DOE Network 2025: Network Research Problems and Challenges for DOE Scientists. Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-02-01

    The growing investments in large science instruments and supercomputers by the US Department of Energy (DOE) hold enormous promise for accelerating the scientific discovery process. They facilitate unprecedented collaborations of geographically dispersed teams of scientists that use these resources. These collaborations critically depend on the production, sharing, moving, and management of, as well as interactive access to, large, complex data sets at sites dispersed across the country and around the globe. In particular, they call for significant enhancements in network capacities to sustain large data volumes and, equally important, the capabilities to collaboratively access the data across computing, storage, and instrument facilities by science users and automated scripts and systems. Improvements in network backbone capacities of several orders of magnitude are essential to meet these challenges, in particular, to support exascale initiatives. Yet, raw network speed represents only a part of the solution. Indeed, the speed must be matched by network and transport layer protocols and higher layer tools that scale in ways that aggregate, compose, and integrate the disparate subsystems into a complete science ecosystem. Just as important, agile monitoring and management services need to be developed to operate the network at peak performance levels. Finally, these solutions must be made an integral part of the production facilities by using sound approaches to develop, deploy, diagnose, operate, and maintain them over the science infrastructure.

  13. Challenges in Education Research in Taiwan: Research Institutes and Organizations, Research Policies, and Problems

    Directory of Open Access Journals (Sweden)

    Jia Li Huang

    2017-02-01

    Full Text Available Since the 1990s, many education researchers and policy makers worldwide have reviewed education research to attempt to provide strategies to improve the quality of such research in their countries. Taiwan’s government has launched policies and funded support to set the benchmark for Taiwan’s leading universities in international academic competition. The external environment of global competition based on research policy influences the ecosystem of social science research production. To assure the quality of education policy, peer review from within the education community is one approach to supplementing the government’s governance, including the establishment of research institutes, promotion, rewards, and research value. This study tracked the mode of academic research and provides an overview of the status of academic education research in Taiwan. Because education research is part of the humanities and social sciences fields, this study identified the challenges in educational research by examining the trend of social science research and by analyzing research organizations, policy, and the evaluation of research performance. Due to the environment of education research in Taiwan is not friendly to education researcher to accumulate papers in SSCI or international journal, additional concerns entail how education research communities can develop and agree on its quality.

  14. Challenges and actual problems in reforming the public administration in the Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Argëtim Saliu

    2016-03-01

    Full Text Available Taking into consideration the fact that the public administration has a very important role in offering services and being a public service to the citizens and business community, as well as the need of improvement and harmonization of the norms and standards with the European Union, as one of the most important demands toward the integration process of Macedonia in the EU, makes this paper necessary to be taken into consideration for at least as a humble research in the area of public administration. Primary goal of this paper is that through comparative and quantitative methods to represent the challenges of reforming the public and state administration in Macedonia. De-politicization, more professional administration services and lowering the number of clerks in administration is one of the main criteria that our country needs to fulfil towards full integration in NATO and EU. The more time passes, the least progress is seen in this process, as we see stagnation in the aspect of quality of services, as well as in the aspect of total number of administrative clerks.

  15. MCT: a Monte Carlo code for time-dependent neutron thermalization problems

    International Nuclear Information System (INIS)

    Cupini, E.; Simonini, R.

    1974-01-01

    In the Monte Carlo simulation of pulse source experiments, the neutron energy spectrum, spatial distribution and total density may be required for a long time after the pulse. If the assemblies are very small, as often occurs in the cases of interest, sophisticated Monte Carlo techniques must be applied which force neutrons to remain in the system during the time interval investigated. In the MCT code a splitting technique has been applied to neutrons exceeding assigned target times, and we have found that this technique compares very favorably with more usual ones, such as the expected leakage probability, giving large gains in computational time and variance. As an example, satisfactory asymptotic thermal spectra with a neutron attenuation of 10 -5 were quickly obtained. (U.S.)

  16. Fly's Eye: a counting camera for thermal neutrons, some applications, problems, and prospects

    International Nuclear Information System (INIS)

    Davidson, J.B.

    1975-01-01

    An area detector for thermal neutrons based on image intensification techniques is described and some capabilities and limitations of the detection system are discussed. Among the former are high spatial resolution high instantaneous counting rate, electronic zoom, time-gating, and integration. The detector is limited in that the maximum counting rate for a resolution element is 60 regularly spaced counts per second. Also, the nonuniformity of response over the detector limits the useful size and requires point-by-point calibration. In addition, a higher efficiency for neutron detection would be desirable. Some typical applications of the system are: crystal inspection, neutron magnetic diffraction topography, and searches for temperature induced changes in diffraction patterns. The future application of solid state television sensors and microchannel plate intensifiers to improve the system are briefly mentioned. (U.S.)

  17. Fly's eye: a counting camera for thermal neutrons: some applications, problems, and prospects

    International Nuclear Information System (INIS)

    Davidson, J.B.

    1976-01-01

    An area detector for thermal neutrons based on image intensification techniques is described. Some capabilities and limitations of the detection system are discussed. Among the former are high spatial resolution, high instantaneous counting rate, electronic zoom, time-gating, and integration. The detector is limited in that the maximum counting rate for a resolution element is 60 regularly spaced counts per second. Also, the nonuniformity of response over the detector puts a limit on the useful size and necessitates point-by-point calibration. In addition, a higher efficiency for neutron detection would be desirable. Some typical applications of the system are crystal inspection, neutron magnetic diffraction topography, and searches for temperature-induced changes in diffraction patterns. The future application of solid-state television sensors and microchannel-plate intensifiers to improve the system is briefly mentioned

  18. Contribution to solving the problem of neutron thermalization in heterogeneous reactor

    International Nuclear Information System (INIS)

    Pop-Jordanov, J. P.

    1963-12-01

    A method for calculating of neutron termalization in heterogeneous rector core was developed. It is more precise than the diffusion method but more complcated. Concerning accuracy it is comparable to non-diffusion methods. Sonce the approach was analytical need for powerful computer is avoided and the description of physical phenomena is more transparent. Convergence is satsfactory. Constraints of the proposed method are: low neutron absorption in the moderator, negligible slowing down in the fuel, and big lattice pitch. The method is applicable for heavy water and graphite moderator systems. Based on the application of this method, procedures were developed for calculating thermal utilzation and neutron temperature. Since 1/v dependence of cross sections is not estimated this metof could be used for long-term reactivity changes

  19. Visualization problems in conductor thermal aging resp. comparison of matlab and gnuplot graphical outputs

    International Nuclear Information System (INIS)

    Beza, J.; Heckenbergerova, J.

    2012-01-01

    The main aim of this paper is comparison of Matlab and Gnuplot software suitability for visualization of results in electro energetic and electro engineering domain. Whole contribution is targeted on specific graphical outputs in problematic of thermal aging of overhead power transmission lines. First, all graphical outputs determined for comparison are visualized in Matlab and furthermore strengths and disadvantages of this implementation are described. Same graphics are then created by free software Gnuplot and finally comparison of both visualization software is made. Last part of the contribution contains main rules and tips about Gnuplot visualization and can be used as User Handbook. The major target of this contribution is to show advantages and shortcomings of Matlab graphical outputs together with introduction of Gnuplot software and suitable alternative for visualization of electrotechnical results. (Authors)

  20. Resorption of radionuclides through the surface of thermal burns and problems of decontamination

    International Nuclear Information System (INIS)

    Il'in, L.A.; Ivannikov, A.T.; Popov, B.A.; Parfenova, I.M.

    1981-01-01

    Resorption of sup(137)Cs, sup(89)Sr, sup(131)I, sup(241)Am during thermal burns of 1-3 degrees and choice of a decontamination method used simultaneously for decontamination and disinfection of burn wounds were studied. It is shown that a degree of burns effects in a certain form on skin penetrability: through burns of 1-2 degrees the resorption increases 1 5-3 times, through burns of the thir degree the resorption decreases slightly as compared to the resorption through intact skin. High efficiency of 3% soap solution for removing radionuclides from burn csurfae of skin has been established. For burns accompanied with the disturbance of epidermis integrality, when considerable absorption of radionuclides is possible, decontamination must be accomplished as soon and complete as possible [ru

  1. Multi-objective stochastic distribution feeder reconfiguration problem considering hydrogen and thermal energy production by fuel cell power plants

    International Nuclear Information System (INIS)

    Niknam, Taher; Kavousi Fard, Abdollah; Baziar, Aliasghar

    2012-01-01

    This paper assesses the operation and management of electrical energy, hydrogen production and thermal load supplement by the Fuel Cell Power Plants (FCPP) in the distribution systems with regard to the uncertainties which exist in the load demand as well as the price of buying natural gas for FCPPs, fuel cost for residential loads, tariff for purchasing electricity, tariff for selling electricity, hydrogen selling price, operation and maintenance cost and the price of purchasing power from the grid. Therefore, a new modified multi-objective optimization algorithm called Teacher-Learning Algorithm (TLA) is proposed to integrate the optimal operation management of Proton Exchange Membrane FCPPs (PEM-FCPPs) and the optimal configuration of the system through an economic model of the PEM-FCPP. In order to improve the total ability of TLA for global search and exploration, a new modification process is suggested such that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated power systems, in this paper for the first time, the DFR problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to see the feasibility and the superiority of the proposed method, a standard test system is investigated as the case study. The simulation results are investigated in four different scenarios to show the effect of hydrogen production and thermal recovery more evidently. -- Highlights: ► Present an economical and thermal modeling of PEM-FCPPs. ► Present an approach for optimal operation of PEM-FCPPs in a stochastic environment. ► Consider benefits of thermal recovery and Hydrogen production for PEM-FCPPs. ► Present several scenarios for management of PEM-FCPPs.

  2. A numerical approach of thermal problems coupling fluid solid and radiation in complex geometries

    International Nuclear Information System (INIS)

    Peniguel, C.; Rupp, I.

    1995-11-01

    In many industrial problems, heat transfer does play an important part. Quite often, radiation, convection and radiation are present simultaneously. This paper presents the numerical tool handling simultaneously these phenomena. Fluid is tackled by the finite element code N3S, radiation (restricted to a non participating medium) and conduction are handled with SYRTHES respectively by a radiosity method and a finite element method. The main originality of the product is that meshes used to solve each phenomenon are completely independent. This allows users to choose the most appropriate spatial discretization for each part or phenomenon. This flexibility requires of course robust and fast data exchange procedures (temperature, convective flux, radiative flux) between the independent grids. This operation is done automatically by the code SYRTHES. One simple problem illustrating the interest of this development is presented at the end of the paper. (author). 6 refs., 8 figs

  3. Experimental challenge to the big-bang nucleosynthesis - Cosmological 7Li problem in BBN

    Science.gov (United States)

    Kubono, S.; Kawabata, T.; Hou, S. Q.; He, J. J.

    2018-04-01

    The primordial nucleosynthesis(BBN) right after the big bang (BB) is one of the key elements that basically support the BB model. The BBN is well known that it produced primarily light elements, and explains reasonably most of the elemental abundances. However, there remains an interesting and serious question. That is so called the cosmological 7Li problem in BBN. The BBN simulations using nuclear data together with the recent detailed micro-wave background measurements explain most of the light elements including D, 4He, etc, but the 7Li abundance is over predicted roughly by a factor of three. Although this problem should be investigated in all the fields relevant including physics and astronomical observations, I will concentrate my discussion on the nuclear physics side, especially the recent progress for studying the last possible major destruction process of 7Be, the 7Be(n,α)4He reaction, which would reduce the overproduction if the cross section is large. There are several efforts recently made for the 7Be(n,α)4He reaction in the world. A new theoretical estimate was made compiling all available data of the mirror reaction 7Li(p,α)4He, suggesting about one order smaller reaction rate than the ones currently being used (Wagoner rate). The n-TOF group measured some part of the s-wave components of the reaction, suggesting that the s-wave contributions are much smaller than the Wagoner rate. The p-wave component was measured clearly at RCNP, Osaka using the time-reverse reaction 4He(α,n)7Be, indicating that the p-wave contribution dominates at the effective temperature region for the BBN. However, the sum of the s-wave and p-wave contributions is about one order of magnitude smaller than the Wagoner rate. It should be of great interest to confirm by the indirect method, Trojan-Horse method to deduce cross sections at the effective temperature region, and also see the cross sections for a wider energy range systematically, which is under way by the BELICOS

  4. Some problems in steady-state thermal conductivity with variable heat transfer rate

    International Nuclear Information System (INIS)

    Malov, Yu.I.; Martinson, L.K.; Pavlov, K.B.

    1975-01-01

    Some boundary-value problems of steady heat conductivity with an alternating heat exchange coefficient have been solved for a cylindrical region. The solutions have been performed as expansion in series with respect to eigenfunctions with the coefficients consistent with infinite systems of linear algebraic equations. A reduction method has been substantiated for those systems. The paper presents results of calculation of the temperature distribution inside the infinite cylinder with concrete tasks of heat exchange coefficient variations on the cylinder surface

  5. THE SOCIAL AND OCCUPATIONAL HEALTH PROBLEMS OF CHILD LABOUR: A CHALLENGE THE WORLD IS FACING

    Directory of Open Access Journals (Sweden)

    Kapil Goel

    2012-03-01

    Full Text Available Eliminating child labour is one of the biggest challenges that the world is facing. Child labour not only causes damage to a child’s physical and mental health but also keeps him deprived of his basic rights to education, development, and freedom. Children of lower socio-economic class are known to be inducted as child labour. The main causes of child labour include poverty, unemployment, excess population and urbanization. The construction sector is one of the most hazardous working environments especially for children. Children are exposed to dangerous machinery causing fatal and non-fatal injuries, while operating or working near them. Children are exposed to strenuous labour, which can affect the musculo-skeletal development of the children. In industries, child workers are exposed to various physical, mental, social occupational hazards resulting in lower growth and poor health status. Working long hours, child labourers are often denied a basic school education, normal social interaction, personal development and emotional support from their family. The Child Labour Act was implemented in India in 1986 that outlaws child labour in certain areas and sets the minimum age of employment at fourteen. Eradicating poverty is only the first step on the road for eliminating child labour. There is an urgent need for intensive focus and research along with political and practical decisions to improve the conditions of working children for the betterment of their health and development. Proper education of the children and banning child labor will help in boosting the success of the country.

  6. Open science, e-science and the new technologies: Challenges and old problems in qualitative research in the social sciences

    Directory of Open Access Journals (Sweden)

    Ercilia García-Álvarez

    2012-12-01

    Full Text Available Purpose: As well as introducing the articles in the special issue titled "Qualitative Research in the Social Sciences", this article reviews the challenges, problems and main advances made by the qualitative paradigm in the context of the new European science policy based on open science and e-Science and analysis alternative technologies freely available in the 2.0 environment and their application to fieldwork and data analysis. Design/methodology: Theoretical review. Practical implications: The article identifies open access technologies with applications in qualitative research such as applications for smartphones and tablets, web platforms and specific qualitative data analysis software, all developed in both the e-Science context and the 2.0 environment. Social implications: The article discusses the possible role to be played by qualitative research in the open science and e-Science context and considers the impact of this new context on the size and structure of research groups, the development of truly collaborative research, the emergence of new ethical problems and quality assessment in review processes in an open environment. Originality/value: The article describes the characteristics that define the new scientific environment and the challenges posed for qualitative research, reviews the latest open access technologies available to researchers in terms of their main features and proposes specific applications suitable for fieldwork and data analysis.

  7. Cosmological challenges in theories with extra dimensions and remarks on the horizon problem

    International Nuclear Information System (INIS)

    Chung, Daniel J. H.; Freese, Katherine

    2000-01-01

    We consider the cosmology that results if our observable universe is a 3-brane in a higher dimensional universe. In particular, we focus on the case where our 3-brane is located at the Z 2 symmetry fixed plane of a Z 2 symmetric five-dimensional spacetime, as in the Horava-Witten model compactified on a Calabi-Yau manifold. As our first result, we find that there can be substantial modifications to the standard Friedmann-Robertson-Walker (FRW) cosmology; as a consequence, a large class of such models is observationally inconsistent. In particular, any relationship between the Hubble constant and the energy density on our brane is possible, including (but not only) FRW. Generically, due to the existence of the bulk and the boundary conditions on the orbifold fixed plane, the relationship is not FRW, and hence cosmological constraints coming from big bang nucleosynthesis, structure formation, and the age of the universe difficult to satisfy. We do wish to point out, however, that some specific choices for the bulk stress-energy tensor components do reproduce normal FRW cosmology on our brane, and we have constructed an explicit example. As our second result, for a broad class of models, we find a somewhat surprising fact: the stabilization of the radius of the extra dimension and hence the four dimensional Planck mass requires unrealistic fine-tuning of the equation of state on our 3-brane. In the last third of the paper, we make remarks about causality and the horizon problem that apply to any theory in which the volume of the extra dimension determines the four-dimensional gravitational coupling. We point out that some of the assumptions that lead to the usual inflationary requirements are modified. (c) 1999 The American Physical Society

  8. Diamond coating deposition by synergy of thermal and laser methods-A problem revisited

    International Nuclear Information System (INIS)

    Ristic, Gordana S.; Trtica, Milan S.; Bogdanov, Zarko D.; Romcevic, Nebojsa Z.; Miljanic, Scepan S.

    2007-01-01

    Diamond coatings were deposited by synergy of the hot filament CVD method and the pulse TEA CO 2 laser, in spectroactive and spectroinactive diamond precursor atmospheres. Resulting diamond coatings are interpreted relying on evidence of scanning electron microscopy as well as microRaman spectroscopy. Thermal synergy component (hot filament) possesses an activating agent for diamond deposition, and contributes significantly to quality and extent of diamond deposition. Laser synergy component comprises a solid surface modification as well as the spectroactive gaseous atmosphere modification. Surface modification consists in changes of the diamond coating being deposited and, at the same time, in changes of the substrate surface structure. Laser modification of the spectroactive diamond precursor atmosphere means specific consumption of the precursor, which enables to skip the deposition on a defined substrate location. The resulting process of diamond coating elimination from certain, desired locations using the CO 2 laser might contribute to tailoring diamond coatings for particular applications. Additionally, the substrate laser modification could be optimized by choice of a proper spectroactive precursor concentration, or by a laser radiation multiple pass through an absorbing medium

  9. Courses for tutors in problem-based learning. Current challenges at four Swedish universities

    Directory of Open Access Journals (Sweden)

    Helen Susan Setterud

    2015-06-01

    Full Text Available The key role of the tutor in problem-based learning (PBL is to help students become selfregulated learners. Tutors need training to acquire the necessary facilitating skills for this task. The aim of this article is to describe and discuss how PBL tutor training is currently arranged at four universities in Sweden: Linköping University, Lund Medical Faculty, Uppsala Medical School and Örebro School of Medicine. Moreover, we seek to analyse how the content and format of the tutor training courses correspond to the desired skills and competencies for PBL tutors described in the literature. We draw especially on work coming out of three pioneering universities for PBL: McMaster University, Canada; Maastricht University, The Netherlands; and Linköping University, Sweden. One aim has been to construct a framework for analysis that uses categories specifying the knowledge base, capabilities and skills to support students’ learning processes which characterise the full-fledged PBL tutor. For this framework, we have used the following categories: Knowledge of PBL and pedagogical theories, Personal traits, Student-centeredness, Ability to handle group processes, and Subject knowledge. We collected descriptions of the course design and content from the four universities, and assessed to what extent these categories were represented within the courses. Our results show that all categories inform the course content at all four universities, though the design varies between courses. In summary, we show that the four PBL tutor training courses are all designed to enable participants to experience PBL first-hand both as members of a tutorial group and as tutors. They all also include a theoretical base and offer opportunities for discussion and reflection with peers; however, there are some differences in design between the courses. According to participants, all four courses provide good preparation for the tutor role. Yet, we see a need for the

  10. Continuous grasp algorithm applied to economic dispatch problem of thermal units

    Energy Technology Data Exchange (ETDEWEB)

    Vianna Neto, Julio Xavier [Pontifical Catholic University of Parana - PUCPR, Curitiba, PR (Brazil). Undergraduate Program at Mechatronics Engineering; Bernert, Diego Luis de Andrade; Coelho, Leandro dos Santos [Pontifical Catholic University of Parana - PUCPR, Curitiba, PR (Brazil). Industrial and Systems Engineering Graduate Program, LAS/PPGEPS], e-mail: leandro.coelho@pucpr.br

    2010-07-01

    The economic dispatch problem (EDP) is one of the fundamental issues in power systems to obtain benefits with the stability, reliability and security. Its objective is to allocate the power demand among committed generators in the most economical manner, while all physical and operational constraints are satisfied. The cost of power generation, particularly in fossil fuel plants, is very high and economic dispatch helps in saving a significant amount of revenue. Recently, as an alternative to the conventional mathematical approaches, modern heuristic optimization techniques such as simulated annealing, evolutionary algorithms, neural networks, ant colony, and tabu search have been given much attention by many researchers due to their ability to find an almost global optimal solution in EDPs. On other hand, continuous GRASP (C-GRASP) is a stochastic local search meta-heuristic for finding cost-efficient solutions to continuous global optimization problems subject to box constraints. Like a greedy randomized adaptive search procedure (GRASP), a C-GRASP is a multi-start procedure where a starting solution for local improvement is constructed in a greedy randomized fashion. The C-GRASP algorithm is validated for a test system consisting of fifteen units, test system that takes into account spinning reserve and prohibited operating zones constrains. (author)

  11. Optimization Problem of Thermal Field on Surface of Revolving Susceptor in Vapor-Phase Epitaxy Reactor

    Science.gov (United States)

    Zhilenkov, A. A.; Chernyi, S. G.; Nyrkov, A. P.; Sokolov, S. S.

    2017-10-01

    Nitrides of group III elements are a very suitable basis for deriving light-emitting devices with the radiating modes lengths of 200-600 nm. The use of such semiconductors allows obtaining full-color RGB light sources, increasing record density of a digital data storage device, getting high-capacity and efficient sources of white light. Electronic properties of such semi-conductors allow using them as a basis for high-power and high-frequency transistors and other electronic devices, the specifications of which are competitive with those of SiC-based devices. Only since 2000, the technology of cultivation of crystals III-N of group has come to the level of wide recognition by both abstract science, and the industry that has led to the creation of the multi-billion dollar market. And this is despite a rather low level of development of the production technology of devices on the basis of III-N of materials. The progress that has happened in the last decade requires the solution of the main problem, constraining further development of this technology today - ensuring cultivation of III-N structures of necessary quality. For this purpose, it is necessary to solve problems of the analysis and optimization of processes in installations of epitaxial growth, and, as a result, optimization of its constructions.

  12. Early life thermal stress: Impact on future thermotolerance, stress response, behavior, and intestinal morphology in piglets exposed to a heat stress challenge during simulated transport

    Science.gov (United States)

    Study objectives were to evaluate the impact of early life thermal stress (ELTS) on thermoregulation, stress, and intestinal health of piglets subjected to a future heat stress (HS) challenge during simulated transport. Approximately 7 d after farrowing, 12 first parity gilts and their litters were ...

  13. Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems

    International Nuclear Information System (INIS)

    Densmore, J.D.; Park, H.; Wollaber, A.B.; Rauenzahn, R.M.; Knoll, D.A.

    2015-01-01

    We present a moment-based acceleration algorithm applied to Monte Carlo simulation of thermal radiative-transfer problems. Our acceleration algorithm employs a continuum system of moments to accelerate convergence of stiff absorption–emission physics. The combination of energy-conserving tallies and the use of an asymptotic approximation in optically thick regions remedy the difficulties of local energy conservation and mitigation of statistical noise in such regions. We demonstrate the efficiency and accuracy of the developed method. We also compare directly to the standard linearization-based method of Fleck and Cummings [1]. A factor of 40 reduction in total computational time is achieved with the new algorithm for an equivalent (or more accurate) solution as compared with the Fleck–Cummings algorithm

  14. Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems

    Energy Technology Data Exchange (ETDEWEB)

    Densmore, J.D., E-mail: jeffery.densmore@unnpp.gov [Bettis Atomic Power Laboratory, P.O. Box 79, West Mifflin, PA 15122 (United States); Park, H., E-mail: hkpark@lanl.gov [Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, P.O. Box 1663, MS B216, Los Alamos, NM 87545 (United States); Wollaber, A.B., E-mail: wollaber@lanl.gov [Computational Physics and Methods Group, Los Alamos National Laboratory, P.O. Box 1663, MS D409, Los Alamos, NM 87545 (United States); Rauenzahn, R.M., E-mail: rick@lanl.gov [Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, P.O. Box 1663, MS B216, Los Alamos, NM 87545 (United States); Knoll, D.A., E-mail: nol@lanl.gov [Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, P.O. Box 1663, MS B216, Los Alamos, NM 87545 (United States)

    2015-03-01

    We present a moment-based acceleration algorithm applied to Monte Carlo simulation of thermal radiative-transfer problems. Our acceleration algorithm employs a continuum system of moments to accelerate convergence of stiff absorption–emission physics. The combination of energy-conserving tallies and the use of an asymptotic approximation in optically thick regions remedy the difficulties of local energy conservation and mitigation of statistical noise in such regions. We demonstrate the efficiency and accuracy of the developed method. We also compare directly to the standard linearization-based method of Fleck and Cummings [1]. A factor of 40 reduction in total computational time is achieved with the new algorithm for an equivalent (or more accurate) solution as compared with the Fleck–Cummings algorithm.

  15. Features of the Numerical Solution of Thermal Destruction Fuel Pins Problems in the Fast Reactor

    Science.gov (United States)

    Usov, E. V.; Butov, A. A.; Klimonov, I. A.; Chuhno, V. I.; Nikolaenko, A. V.; Zhdanov, V. S.; Pribaturin, N. A.; Strizhov, V. F.

    2017-11-01

    In this paper the description of the basic equations which can be used for calculation of melting of fuel and cladding of the fast reactor, moving of the melt on a fuel pin surface and its solidification is presented. The special attention is given speed of calculation algorithms and fidelity of the phenomena which are observed at a stage of severe accidents in fast reactors. For check of working capacity of initial models, numerical calculations of Stefan-type problems on front movement of melting/solidification in cylindrical geometry are presented. Comparison with the solutions received by known analytical methods is executed. For validation of the numerical realization of calculation algorithms the analysis is carried out and experiments in which melting of the model fuel pins of fast reactors was studied are chosen. On the basis of the chosen experiments calculation schemes taking into account initial and boundary conditions are prepared and modeling is performed. Modeling results are shown in the present paper. Estimation of calculation error of the basic physical parameters is done by results of the modeling and conclusions are drawn on a correctness of algorithms operation.

  16. Fractional Step Like Schemes for Free Surface Problems with Thermal Coupling Using the Lagrangian PFEM

    Science.gov (United States)

    Aubry, R.; Oñate, E.; Idelsohn, S. R.

    2006-09-01

    The method presented in Aubry et al. (Comput Struc 83:1459-1475, 2005) for the solution of an incompressible viscous fluid flow with heat transfer using a fully Lagrangian description of motion is extended to three dimensions (3D) with particular emphasis on mass conservation. A modified fractional step (FS) based on the pressure Schur complement (Turek 1999), and related to the class of algebraic splittings Quarteroni et al. (Comput Methods Appl Mech Eng 188:505-526, 2000), is used and a new advantage of the splittings of the equations compared with the classical FS is highlighted for free surface problems. The temperature is semi-coupled with the displacement, which is the main variable in a Lagrangian description. Comparisons for various mesh Reynolds numbers are performed with the classical FS, an algebraic splitting and a monolithic solution, in order to illustrate the behaviour of the Uzawa operator and the mass conservation. As the classical fractional step is equivalent to one iteration of the Uzawa algorithm performed with a standard Laplacian as a preconditioner, it will behave well only in a Reynold mesh number domain where the preconditioner is efficient. Numerical results are provided to assess the superiority of the modified algebraic splitting to the classical FS.

  17. An enhanced artificial bee colony algorithm (EABC) for solving dispatching of hydro-thermal system (DHTS) problem.

    Science.gov (United States)

    Yu, Yi; Wu, Yonggang; Hu, Binqi; Liu, Xinglong

    2018-01-01

    The dispatching of hydro-thermal system is a nonlinear programming problem with multiple constraints and high dimensions and the solution techniques of the model have been a hotspot in research. Based on the advantage of that the artificial bee colony algorithm (ABC) can efficiently solve the high-dimensional problem, an improved artificial bee colony algorithm has been proposed to solve DHTS problem in this paper. The improvements of the proposed algorithm include two aspects. On one hand, local search can be guided in efficiency by the information of the global optimal solution and its gradient in each generation. The global optimal solution improves the search efficiency of the algorithm but loses diversity, while the gradient can weaken the loss of diversity caused by the global optimal solution. On the other hand, inspired by genetic algorithm, the nectar resource which has not been updated in limit generation is transformed to a new one by using selection, crossover and mutation, which can ensure individual diversity and make full use of prior information for improving the global search ability of the algorithm. The two improvements of ABC algorithm are proved to be effective via a classical numeral example at last. Among which the genetic operator for the promotion of the ABC algorithm's performance is significant. The results are also compared with those of other state-of-the-art algorithms, the enhanced ABC algorithm has general advantages in minimum cost, average cost and maximum cost which shows its usability and effectiveness. The achievements in this paper provide a new method for solving the DHTS problems, and also offer a novel reference for the improvement of mechanism and the application of algorithms.

  18. An enhanced artificial bee colony algorithm (EABC for solving dispatching of hydro-thermal system (DHTS problem.

    Directory of Open Access Journals (Sweden)

    Yi Yu

    Full Text Available The dispatching of hydro-thermal system is a nonlinear programming problem with multiple constraints and high dimensions and the solution techniques of the model have been a hotspot in research. Based on the advantage of that the artificial bee colony algorithm (ABC can efficiently solve the high-dimensional problem, an improved artificial bee colony algorithm has been proposed to solve DHTS problem in this paper. The improvements of the proposed algorithm include two aspects. On one hand, local search can be guided in efficiency by the information of the global optimal solution and its gradient in each generation. The global optimal solution improves the search efficiency of the algorithm but loses diversity, while the gradient can weaken the loss of diversity caused by the global optimal solution. On the other hand, inspired by genetic algorithm, the nectar resource which has not been updated in limit generation is transformed to a new one by using selection, crossover and mutation, which can ensure individual diversity and make full use of prior information for improving the global search ability of the algorithm. The two improvements of ABC algorithm are proved to be effective via a classical numeral example at last. Among which the genetic operator for the promotion of the ABC algorithm's performance is significant. The results are also compared with those of other state-of-the-art algorithms, the enhanced ABC algorithm has general advantages in minimum cost, average cost and maximum cost which shows its usability and effectiveness. The achievements in this paper provide a new method for solving the DHTS problems, and also offer a novel reference for the improvement of mechanism and the application of algorithms.

  19. Implementation and evaluation of treatments for children and adolescents with conduct problems: Findings, challenges, and future directions.

    Science.gov (United States)

    Kazdin, Alan E

    2018-01-01

    The intervention work of our clinical-research team has focused on the treatment of children and young adolescents referred for Conduct Disorder or Oppositional Defiant Disorder. We have evaluated two interventions: parent management training (PMT) and cognitive problem-solving skills training in several randomized controlled clinical trials. Our findings have indicated the treatments, alone or in combination, produce reliable and significant reductions in oppositional, aggressive, and antisocial behaviour and increases in prosocial behaviour among children. Parent dysfunction (depression, multiple symptom domains) and stress decline and family relations improve as well. Apart from outcome studies, we have studied the therapeutic alliance, factors that influence dropping out and retaining cases, and variations of treatment delivery (e.g., computer based, reduced therapist contact). The article considers challenges in conducting controlled trials in clinic settings (e.g., recruiting cases, maintaining treatment integrity, securing funding) and activities related to implementation that are not easily covered within the confines of research articles. The article ends with a discussion of one of the treatments (PMT) and the broad role it can play in treatment, prevention, and help with many parenting challenges of everyday life.

  20. Effect of Rotation for Two-Temperature Generalized Thermoelasticity of Two-Dimensional under Thermal Shock Problem

    Directory of Open Access Journals (Sweden)

    Kh. Lotfy

    2013-01-01

    Full Text Available The theory of two-temperature generalized thermoelasticity based on the theory of Youssef is used to solve boundary value problems of two-dimensional half-space. The governing equations are solved using normal mode method under the purview of the Lord-Şhulman (LS and the classical dynamical coupled theory (CD. The general solution obtained is applied to a specific problem of a half-space subjected to one type of heating, the thermal shock type. We study the influence of rotation on the total deformation of thermoelastic half-space and the interaction with each other under the influence of two temperature theory. The material is homogeneous isotropic elastic half-space. The methodology applied here is use of the normal mode analysis techniques that are used to solve the resulting nondimensional coupled field equations for the two theories. Numerical results for the displacement components, force stresses, and temperature distribution are presented graphically and discussed. The conductive temperature, the dynamical temperature, the stress, and the strain distributions are shown graphically with some comparisons.

  1. Grand Challenge Problem 10

    DEFF Research Database (Denmark)

    Dirckinck-Holmfeld, Lone; Balacheff, Nicolas; Bottino, Rosa Maria

    2016-01-01

    Small and medium sized research labs (SMLs) are dominating European TEL research. This is justified by the great numbers of countries and regions in Europe needing to develop a research and innovation competence to facilitate the diverse educational systems contextualized in various institutional...

  2. On Inverse Coefficient Heat-Conduction Problems on Reconstruction of Nonlinear Components of the Thermal-Conductivity Tensor of Anisotropic Bodies

    Science.gov (United States)

    Formalev, V. F.; Kolesnik, S. A.

    2017-11-01

    The authors are the first to present a closed procedure for numerical solution of inverse coefficient problems of heat conduction in anisotropic materials used as heat-shielding ones in rocket and space equipment. The reconstructed components of the thermal-conductivity tensor depend on temperature (are nonlinear). The procedure includes the formation of experimental data, the implicit gradient-descent method, the economical absolutely stable method of numerical solution of parabolic problems containing mixed derivatives, the parametric identification, construction, and numerical solution of the problem for elements of sensitivity matrices, the development of a quadratic residual functional and regularizing functionals, and also the development of algorithms and software systems. The implicit gradient-descent method permits expanding the quadratic functional in a Taylor series with retention of the linear terms for the increments of the sought functions. This substantially improves the exactness and stability of solution of the inverse problems. Software systems are developed with account taken of the errors in experimental data and disregarding them. On the basis of a priori assumptions of the qualitative behavior of the functional dependences of the components of the thermal-conductivity tensor on temperature, regularizing functionals are constructed by means of which one can reconstruct the components of the thermal-conductivity tensor with an error no higher than the error of the experimental data. Results of the numerical solution of the inverse coefficient problems on reconstruction of nonlinear components of the thermal-conductivity tensor have been obtained and are discussed.

  3. Water Chemistry and Chemistry Monitoring at Thermal and Nuclear Power Plants: Problems and Tasks (Based on Proceedings of Conferences)

    Science.gov (United States)

    Larin, B. M.

    2018-02-01

    In late May-early June 2017, two international science and technology conferences on problems of water chemistry and chemistry monitoring at thermal and nuclear power plants were held. The participants of both the first conference held at OAO VTI and the second conference that took place at NITI formulated the problems of the development of the regulatory base and implementation of promising water treatment technologies and outlined the ways of improving the water chemistry and chemistry monitoring at TPPs and NPPs for the near future. It was pointed out that the new amine-containing VTIAMIN agent developed by OAO VTI had been successfully tested on the power-generating units equipped with steam-gas plants to establish the minimum excess of the film-forming amine in the power-generating unit circuit that ensures the protection of the metal as 5-10 μg/dm3. A flow-injection technique for the analysis of trace concentrations of chlorides was proposed; the technique applied to the condensate of the 1000-MW steam turbine of the NPP power-generating unit yields the results comparable with the results obtained by the ion chromatography and the potentiometric method using the solver electrode. The participants of the conferences were demonstrated new Russian instruments to analyze the water media at the TPPs and NPPs, including the total organic carbon analyzer and the analyzer of mineral impurities in the condensate and feed water, that won a gold medal at the 45th International Exhibition of Inventions held in Geneva this April.

  4. Adhesion and interface problems of EB-PVD thermal barrier coatings; Grenzschichtproblematik und Haftung von EB-PVD-Waermedaemmschichtsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Fritscher, K.; Leyens, C. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Werkstoff-Forschung

    1996-12-31

    Loss of adhesion in thermal insulation layers produced by EB-PVD may be caused by surface morphologies or oxide phases resulting from previous process stages, e.g. shot peening, or inappropriate annealing conditions. These undesirable oxide phases are mostly spinels and silicates which pose mechanical problems. Annealing and densification must be modified in order to promote the formation of {alpha}-Al{sub 2}O{sub 3} layers. It may also be possible to avoid certain categories of flaws by changing one material partner (e.g. by using {beta}-NiAl-free adhesive layers). [Deutsch] Die Ursachen der Einbussen der Haftung in WDS-Systemen aus EB-PVD-Fertigung liegen oft in der Ausbildung von Oberflaechenmorphologien oder von Oxidphasen begruendet, die aus den der WDS-Beschichtung vorangehenden Verfahrensschritten wie z.B. des Glasperlstrahlens und von unangemessenen Gluehbedingungen herruehren koennen. Bei diesen unerwuenschten Oxidphasen handelt es sich u.a. um Spinelle und Silikate, die in mechanischer Hinsicht problematisch sind. Glueh- und Verdichtungsroutinen sind entsprechend zu modifizieren, um die Bildung von {alpha}-Al{sub 2}O{sub 3}-Schichten zu foerdern. Moeglicherweise sind gewisse Fehlerkategorien bereits dadurch zu umgehen, dass ein Materialpartner geaendert wird (Beispiel: {beta}-NiAl-freie Haftschichten anwenden). (orig.)

  5. Management Strategies of Perceived Challenges and Problems of Old People in Ihitte-Uboma Local Government Area of Imo State, Nigeria

    Science.gov (United States)

    Ojukwu, M. O.; Woko, S. I.

    2016-01-01

    It has been revealed that over the years, the number of the aged in the world has been on a steady increase. This rising number has great implications for government, researchers, families, youth and the society at large. There is therefore, the proper need for the understanding of the nature problems and challenges as well as the management…

  6. Mental health problems among individuals with persistent health challenges from adolescence to young adulthood: a population-based longitudinal study in Norway

    Directory of Open Access Journals (Sweden)

    Sølvi Helseth

    2016-09-01

    Full Text Available Abstract Background Persistent health challenges are increasing throughout the world. It has been shown that adolescents with persistent health challenges are at greater risk of having mental health problems than their healthy peers. However, these studies are mainly cross-sectional, and little is known about the transition to adulthood. Thus, the aim of this study was to examine how mental health problems in adolescents and young adults with persistent health challenges vary during adolescence and in the transition to young adulthood. Methods The study used longitudinal and time-series data from the “Young in Norway” study. A sample of adolescents was prospectively followed from adolescence to young adulthood with measures at four different time points (n = 3,087; T1–T4: 2921 adolescents (12–19 years participated at T1 and T2, while 2448 young adults participated at T3 and T4. Persistent health challenges, age, gender, mental health problems and parental socio-economic status were measured in the longitudinal survey. Regression models were applied to estimate associations between persistent health challenges (understood as having a chronic health condition or disability and mental health problems during adolescence and young adulthood. Different models were tested for chronic health conditions and disability. Results Adolescents with disability had higher scores for depressive and anxiety symptoms, loneliness and self-concept instability, and lower scores for self-worth, appearance satisfaction, scholastic competence and social acceptance compared with adolescents without disability. In young adulthood, there were also significant associations between disability and most mental health problems. The longitudinal associations between chronic health conditions and mental health problems during adolescence and young adulthood showed that significant associations between chronic health conditions and mental health problems were only

  7. Enhancing Problem-Based Learning Designs with a Single E-Learning Scaffolding Tool: Two Case Studies Using Challenge FRAP

    Science.gov (United States)

    Stewart, Terry M.; MacIntyre, William R.; Galea, Victor J.; Steel, Caroline H.

    2007-01-01

    Problem-based learning (PBL) is a powerful instructional approach. By working through assessable complex problem-solving tasks learners can be encouraged to actively engage in investigation and inquiry and to use high level cognitive thought processes to solve real-life problems in professional contexts. A critical element of a successful PBL…

  8. A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring

    Directory of Open Access Journals (Sweden)

    Zarei S

    2015-05-01

    Full Text Available Background: Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy. It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones. Objective: The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring. Methods: In this study, mothers of 35 healthy 3-5 year old children (control group and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines. Results: We found a significant association between either the call time (P=0.002 or history of mobile phone use (months used and speech problems in the offspring (P=0.003. However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring.

  9. Addressing Complex Problems: Using Authentic Audiences and Challenges to Develop Adaptive Leadership and Socially Responsible Agency in Leadership Learners

    Science.gov (United States)

    Andenoro, Anthony C.; Sowcik, Matthew J.; Balser, Teresa C.

    2017-01-01

    Complex and adaptive challenges threaten human well-being and sustainability. However, our leadership graduates often lack the capacity and or commitment to address these challenges in a meaningful way. This paper details a five-year study exploring the impact of an interdisciplinary undergraduate course on the development of global capacities,…

  10. A coupled magneto-thermo-elastic problem in a perfectly conducting elastic half-space with thermal relaxation

    Directory of Open Access Journals (Sweden)

    S. K. Roy-Choudhuri

    1990-01-01

    Full Text Available In the present paper we consider the magneto-thermo-elastic wave produced by a thermal shock in a perfectly conducting elastic half-space. Here the Lord-Shulman theory of thermoelasticity [1] is used to account for the interaction between the elastic and thermal fields. The solution obtained in analytical form reduces to those of Kaliski and Nowacki [2] when the coupling between the temperature and strain fields and the relaxation time are neglected. The results also agree with those of Massalas and DaLamangas [3] in absence of the thermal relaxation time.

  11. A new approach for optimization of thermal power plant based on the exergoeconomic analysis and structural optimization method: Application to the CGAM problem

    International Nuclear Information System (INIS)

    Seyyedi, Seyyed Masoud; Ajam, Hossein; Farahat, Said

    2010-01-01

    In large thermal systems, which have many design variables, conventional mathematical optimization methods are not efficient. Thus, exergoeconomic analysis can be used to assist optimization in these systems. In this paper a new iterative approach for optimization of large thermal systems is suggested. The proposed methodology uses exergoeconomic analysis, sensitivity analysis, and structural optimization method which are applied to determine sum of the investment and exergy destruction cost flow rates for each component, the importance of each decision variable and minimization of the total cost flow rate, respectively. Applicability to the large real complex thermal systems and rapid convergency are characteristics of this new iterative methodology. The proposed methodology is applied to the benchmark CGAM cogeneration system to show how it minimizes the total cost flow rate of operation for the installation. Results are compared with original CGAM problem.

  12. Grip on challenging behaviour: a multidisciplinary care programme for managing behavioural problems in nursing home residents with dementia. Study protocol

    NARCIS (Netherlands)

    Zwijsen, S.A.; Smalbrugge, M.; Zuidema, S.U.; Koopmans, R.T.C.M.; Bosmans, J.E.; Tulder, M.W. van; Eefsting, J.A.; Gerritsen, D.L.; Pot, A.M.

    2011-01-01

    BACKGROUND: Behavioural problems are common in nursing home residents with dementia and they often are burdensome for both residents and nursing staff. In this study, the effectiveness and cost-effectiveness of a new care programme for managing behavioural problems will be evaluated. METHODS/DESIGN:

  13. Grip on challenging behaviour: a multidisciplinary care programme for managing behavioural problems in nursing home residents with dementia. Study protocol

    NARCIS (Netherlands)

    Zwijsen, S.A.; Smalbrugge, M.; Zuidema, S.U.; Koopmans, R.T.C.M.; Bosmans, J.E.; van Tulder, M.W.; Eefsting, J.A.; Gerritsen, D.L.; Pot, A.M.

    2011-01-01

    Background: Behavioural problems are common in nursing home residents with dementia and they often are burdensome for both residents and nursing staff. In this study, the effectiveness and cost-effectiveness of a new care programme for managing behavioural problems will be evaluated. Methods/Design.

  14. Project for solving of environmental problems caused by ash emission and deposition from the thermal power plant 'Nikola Tesla' at Obrenovac

    International Nuclear Information System (INIS)

    Simonovic, B.R.; Vukmirovic, Z.; Ilic, M.

    2002-01-01

    The problem of ash emission and deposition from the Thermal Power Plant 'Nikola Tesla' (TPPNT) in Obrenovac commences with the date of their construction. Up to now, mainly, some analysis of several possible influences of ash (emitted or deposited on the ash and slug dump) was done. We believe that is time now, due to the consequences for a long time, to pose and to resolve the whole problem of ash emission and deposition from TPPNT Obrenovac. Due to the very big production capacity, an enormous amount of fly ash (particle size of 90-200 μm) is emitted to a large area near Obrenovac. Very large quantities of ash and slug (more than 2 millions tons annually) produced during coal burning were deposited on the dump very close to the river Sava. Some of the multiple consequences due to elution of heavy metals, water spilling from the dump and mixing with ground water and surface water of river Sava, weathering of fine particles of ash by wind, acid rains near to the thermal power plants, and other influences of flying and deposited ash on the environment of the whole area are always present. Due to the complexity of the posed problem, a multidisciplinary experts' team was formed to cover all aspects of negative influences of ash emission and deposition from TPPNT Obrenovac. Our project comprises a large number of subprojects covering different problem solving, diminution or removal of all negative influences according to European standards and regulations. (author)

  15. Potential steam generator tube rupture in the presence of severe accident thermal challenge and tube flaws due to foreign object wear

    International Nuclear Information System (INIS)

    Liao, Y.; Guentay, S.

    2009-01-01

    This study develops a methodology to assess the probability for the degraded PWR steam generator to rupture first in the reactor coolant pressure boundary, under severe accident conditions with counter-current natural circulating high temperature gas in the hot leg and SG tubes. The considered SG tube flaws are caused by foreign object wear, which in recent years has emerged as a major inservice degradation mechanism for the new generation tubing materials. The first step develops the statistical distributions for the flaw frequency, size, and the flaw location with respect to the tube length and the tube's tubesheet position, based on data of hundreds of flaws reported in numerous SG inservice inspection reports. The next step performs thermal-hydraulic analysis using the MELCOR code and recent CFD findings to predict the thermal challenge to the degraded tubes and the tube-to-tube difference in thermal response at the SG entrance. The final step applies the creep rupture models in the Monte Carlo random walk to test the potential for the degraded SG to rupture before the surge line. The mean and range of the SG tube rupture probability can be applied to estimate large early release frequency in probabilistic safety assessment.

  16. A decade of research on health content in the media: the focus on health challenges and sociocultural context and attendant informational and ideological problems.

    Science.gov (United States)

    Kline, Kimberly N

    2006-01-01

    There is a burgeoning interest in the health and illness content of popular media in the domains of advertising, journalism, and entertainment. This article reviews the past 10 years of this research, describing the relationship between the health topics addressed in the research, the shifting focus of concerns about the media, and, ultimately, the variation in problems for health promotion. I suggest that research attending to topics related to bodily health challenges focused on whether popular media accurately or appropriately represented health challenges. The implication was that there is some consensus about more right or wrong, complete or incomplete ways of representing an issue; the problem was that the media are generally wrong. Alternatively, research addressing topics related to sociocultural context issues focused on how certain interests are privileged in the media. The implication was that competing groups are making claims on the system, but the problem was that popular media marginalizes certain interests. In short, popular media is not likely to facilitate understandings helpful to individuals coping with health challenges and is likely to perpetuate social and political power differentials with regard to health-related issues. I conclude by offering some possibilities for future health media content research.

  17. A numerical approach of thermal problems coupling fluid solid and radiation in complex geometries; Approche numerique de problemes thermiques couplant fluides, solides et rayonnement en geometries complexes

    Energy Technology Data Exchange (ETDEWEB)

    Peniguel, C; Rupp, I

    1995-11-01

    In many industrial problems, heat transfer does play an important part. Quite often, radiation, convection and radiation are present simultaneously. This paper presents the numerical tool handling simultaneously these phenomena. Fluid is tackled by the finite element code N3S, radiation (restricted to a non participating medium) and conduction are handled with SYRTHES respectively by a radiosity method and a finite element method. The main originality of the product is that meshes used to solve each phenomenon are completely independent. This allows users to choose the most appropriate spatial discretization for each part or phenomenon. This flexibility requires of course robust and fast data exchange procedures (temperature, convective flux, radiative flux) between the independent grids. This operation is done automatically by the code SYRTHES. One simple problem illustrating the interest of this development is presented at the end of the paper. (author). 6 refs., 8 figs.

  18. Quality-assurance study of the special - purpose finite-element program - SPECTROM: I. Thermal, thermoelastic, and viscoelastic problems

    International Nuclear Information System (INIS)

    Wagner, R.A.

    1980-12-01

    This comparison study involves a preliminary verification of finite element calculations. The methodology of the comparison study consists of solving four example problems with both the SPECTROM finite element program and the MARC-CDC general purpose finite element program. The results show close agreement for all example problems

  19. Survey of the results of a two- and three-dimensional kinetics benchmark problem typical for a thermal reactor

    International Nuclear Information System (INIS)

    Werner, W.

    1975-01-01

    In 1973, NEACRP and CSNI posed a number of kinetic benchmark problems intended to be solved by different groups. Comparison of the submitted results should lead to estimates on the accuracy and efficiency of the employed codes. This was felt to be of great value since the codes involved become more and more important in the field of reactor safety. In this paper the results of the 2d and 3d benchmark problem for a BWR are presented. The specification of the problem is included in the appendix of this survey. For the 2d benchmark problem, 5 contributions have been obtained, while for the 3d benchmark problem 2 contributions have been submitted. (orig./RW) [de

  20. Jamaica is Without a National Sexual Harassment Policy: Challenges, Consequences, Health Problems and the Need for a National Policy Framework

    OpenAIRE

    R. Peters; P.A. Bourne

    2012-01-01

    Humans are sexual as they are physical beings. Simply put, sexual relations are embedded in their composition and so legislations are needed to protect vulnerable groups such as children, poor, women, orphans, elderly, mentally and physically disabled people and adolescents from sexual exploitations. The current study will explore why Jamaica needs a national sexual harassment policy, the challenges without a policy and the difficulties in formulating a policy in such a highly sexed culture. ...

  1. Finite Element Modeling of Material Fatigue and Cracking Problems for Steam Power System HP Devices Exposed to Thermal Shocks

    Directory of Open Access Journals (Sweden)

    Pawlicki Jakub

    2016-09-01

    Full Text Available The paper presents a detailed analysis of the material damaging process due to low-cycle fatigue and subsequent crack growth under thermal shocks and high pressure. Finite Element Method (FEM model of a high pressure (HP by-pass valve body and a steam turbine rotor shaft (used in a coal power plant is presented. The main damaging factor in both cases is fatigue due to cycles of rapid temperature changes. The crack initiation, occurring at a relatively low number of load cycles, depends on alternating or alternating-incremental changes in plastic strains. The crack propagation is determined by the classic fracture mechanics, based on finite element models and the most dangerous case of brittle fracture. This example shows the adaptation of the structure to work in the ultimate conditions of high pressure, thermal shocks and cracking.

  2. Thermal leptogenesis and the gravitino problem in the Asaka-Yanagida axion/axino dark matter scenario

    International Nuclear Information System (INIS)

    Baer, Howard; Lessa, Andre; Kraml, Sabine; Sekmen, Sezen

    2011-01-01

    A successful implementation of thermal leptogenesis requires the re-heat temperature after inflation T R to exceed ∼ 2 × 10 9 GeV. Such a high T R value typically leads to an overproduction of gravitinos in the early universe, which will cause conflicts, mainly with BBN constraints. Asaka and Yanagida (AY) have proposed that these two issues can be reconciled in the context of the Peccei-Quinn augmented MSSM (PQMSSM) if one adopts a mass hierarchy m(sparticle) > m(gravitino)>m(axino), with m(axino) ∼ keV. In this case, sparticle decays bypass the gravitino, and decay more quickly to the axino LSP, thus avoiding the BBN constraints. In addition, thermally produced gravitinos decay inertly to axion+axino, also avoiding BBN constraints. We calculate the relic abundance of mixed axion/axino dark matter in the AY scenario, and investigate under what conditions a value of T R sufficient for thermal leptogenesis can be generated. A high value of PQ breaking scale f a is needed to suppress overproduction of axinos, while a small vacuum misalignment angle θ i is needed to suppress overproduction of axions. The large value of f a results in late decaying neutralinos. We show that, to avoid BBN constraints, the AY scenario requires a rather low thermal abundance of neutralinos, while higher values of neutralino mass also help. We combine these constraint calculations along with entropy production from late decaying saxions, and find the saxion needs to be typically at least several times heavier than the gravitino. A successful implementation of the AY scenario suggests that LHC should discover a spectrum of SUSY particles consistent with weak scale supergravity; that the apparent neutralino abundance is low; that an axion direct detection signal (probably with m a in the sub-μeV range) may be possible, but no direct or indirect signals for WIMP dark matter should be observed

  3. Advancing the "Colorado Graduates" Agenda: Understanding the Dropout Problem and Mobilizing to Meet the Graduation Challenge. [Executive Summary

    Science.gov (United States)

    Mac Iver, Martha Abele; Balfanz, Robert; Byrnes, Vaughan

    2009-01-01

    The ambitious goal set by Colorado's governor to address the state's dropout problem is a model for the nation. Helping thousands of young people to receive their high school diplomas instead of leaving school without them is a crucial step in improving the quality of life for all Colorado residents. Accomplishing this goal will require focused…

  4. Challenging Temperament, Teacher-Child Relationships, and Behavior Problems in Urban Low-Income Children: A Longitudinal Examination

    Science.gov (United States)

    McCormick, Meghan P.; Turbeville, Ashley R.; Barnes, Sophie P.; McClowry, Sandee G.

    2014-01-01

    Research Findings: Racial/ethnic minority low-income children with temperaments high in negative reactivity are at heightened risk for developing disruptive behavior problems. Teacher-child relationships characterized by high levels of closeness and low levels of conflict may protect against the development of disruptive behaviors in school. The…

  5. Reply to 'Comment on 'Surface-impedance approach solves problems with the thermal Casimir force between real metals''

    International Nuclear Information System (INIS)

    Geyer, B.; Klimchitskaya, G.L.; Mostepanenko, V.M.

    2004-01-01

    The preceding Comment discusses in detail the main idea of our paper [Phys. Rev. A 67, 062102 (2003)], namely that one cannot substitute the Drude dielectric function into the Lifshitz formula for the thermal Casimir force in the frequency region where a real current of conduction electrons leads to Joule heating in the metal. In that Comment, it is claimed that this idea would be in contradiction to the fluctuation-dissipation theorem. In this Reply we present an explicit explanation why there is no contradiction. In the second part of the Comment an alternative method is suggested, different from the one used in our paper, to calculate the thermal Casimir force in the framework of the impedance approach. This method is in support of a previous prediction by Svetovoy and Lokhanin, criticized by us, that there exists a relatively large thermal correction to the Casimir force between real metals at small separations. Here we present strong quantitative arguments in favor of the statement that the method of the Comment is in violation of the Nernst heat theorem. We also demonstrate that it is in contradiction with experiment. The approach of our paper is shown to be in agreement with both thermodynamics and experimental data

  6. A unified analysis of kinetic models for the problem of thermal creep based on the boundary conditions of Cercignani-Lampis for heterogeneous plates

    International Nuclear Information System (INIS)

    Rosa, Cinara Ewerling da; Knackfuss, Rosenei Felippe

    2013-01-01

    In this work is presented a series of numerical results and graphical comparisons of the physical quantities of interest such as: the velocity profile and the heat on profile. This formulation is developed for the problem of Thermal Creep, where the gas is moving between two parallel plates with different chemical constitutions (heterogeneous plates) due to a temperature gradient. The flow of a rarefied gas, is investigated with special attention to the gas-surface interaction, modeled by the Cercignani-Lampis kernel, that unlike Maxwell's scattering kernel, is defined in terms of two accommodation coefficients (normal and tangential) to represent the physical properties of the gas. The kinetic theory for rarefied gas dynamics, derived from the linearized Boltzmann equation, is developed in an unified approach, to the BGK model, S model, GJ model and MRS model. In the search for solutions to solve the problem of Thermal Creep with kernel of the Cercignani-Lampis, we used a analytical version of the discrete ordinates method (ADO) based on an arbitrary quadrature scheme, under which is determined a problem of eigenvalues and their respective separation constants. Numerical results are developed by the computer program FORTRAN. (author)

  7. Pressurized Thermal Shock, Pts

    International Nuclear Information System (INIS)

    Boyd, C.

    2008-01-01

    Pressurized Thermal Shock (Pts) refers to a condition that challenges the integrity of the reactor pressure vessel. The root cause of this problem is the radiation embrittlement of the reactor vessel. This embrittlement leads to an increase in the reference temperature for nil ductility transition (RTNDT). RTNDT can increase to the point where the reactor vessel material can loose fracture toughness during overcooling events. The analysis of the risk of having a Pts for a specific plant is a multi-disciplinary problem involving probabilistic risk analysis (PRA), thermal-hydraulic analysis, and ultimately a structural and fracture analysis of the vessel wall. The PRA effort involves the postulation of overcooling events and ultimately leads to an integrated risk analysis. The thermal-hydraulic effort involves the difficult task of predicting the system behavior during a postulated overcooling scenario with a special emphasis on predicting the thermal and mechanic loadings on the reactor pressure vessel wall. The structural and fracture analysis of the reactor vessel wall relies on the thermal-hydraulic conditions as boundary conditions. The US experience has indicated that medium and large diameter primary system breaks dominate the risk of Pts along with scenarios that involve a stuck open valve (and associated system cooldown) that recloses resulting in system re-pressurization while the vessel wall is cool.

  8. Calculation of the Thermal Radiation Benchmark Problems for a CANDU Fuel Channel Analysis Using the CFX-10 Code

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyoung Tae; Park, Joo Hwan; Rhee, Bo Wook

    2006-07-15

    To justify the use of a commercial Computational Fluid Dynamics (CFD) code for a CANDU fuel channel analysis, especially for the radiation heat transfer dominant conditions, the CFX-10 code is tested against three benchmark problems which were used for the validation of a radiation heat transfer in the CANDU analysis code, a CATHENA. These three benchmark problems are representative of the CANDU fuel channel configurations from a simple geometry to whole fuel channel geometry. With assumptions of a non-participating medium completely enclosed with the diffuse, gray and opaque surfaces, the solutions of the benchmark problems are obtained by the concept of surface resistance to radiation accounting for the view factors and the emissivities. The view factors are calculated by the program MATRIX version 1.0 avoiding the difficulty of hand calculation for the complex geometries. For the solutions of the benchmark problems, the temperature or the net radiation heat flux boundary conditions are prescribed for each radiating surface to determine the radiation heat transfer rate or the surface temperature, respectively by using the network method. The Discrete Transfer Model (DTM) is used for the CFX-10 radiation model and its calculation results are compared with the solutions of the benchmark problems. The CFX-10 results for the three benchmark problems are in close agreement with these solutions, so it is concluded that the CFX-10 with a DTM radiation model can be applied to the CANDU fuel channel analysis where a surface radiation heat transfer is a dominant mode of the heat transfer.

  9. Calculation of the Thermal Radiation Benchmark Problems for a CANDU Fuel Channel Analysis Using the CFX-10 Code

    International Nuclear Information System (INIS)

    Kim, Hyoung Tae; Park, Joo Hwan; Rhee, Bo Wook

    2006-07-01

    To justify the use of a commercial Computational Fluid Dynamics (CFD) code for a CANDU fuel channel analysis, especially for the radiation heat transfer dominant conditions, the CFX-10 code is tested against three benchmark problems which were used for the validation of a radiation heat transfer in the CANDU analysis code, a CATHENA. These three benchmark problems are representative of the CANDU fuel channel configurations from a simple geometry to whole fuel channel geometry. With assumptions of a non-participating medium completely enclosed with the diffuse, gray and opaque surfaces, the solutions of the benchmark problems are obtained by the concept of surface resistance to radiation accounting for the view factors and the emissivities. The view factors are calculated by the program MATRIX version 1.0 avoiding the difficulty of hand calculation for the complex geometries. For the solutions of the benchmark problems, the temperature or the net radiation heat flux boundary conditions are prescribed for each radiating surface to determine the radiation heat transfer rate or the surface temperature, respectively by using the network method. The Discrete Transfer Model (DTM) is used for the CFX-10 radiation model and its calculation results are compared with the solutions of the benchmark problems. The CFX-10 results for the three benchmark problems are in close agreement with these solutions, so it is concluded that the CFX-10 with a DTM radiation model can be applied to the CANDU fuel channel analysis where a surface radiation heat transfer is a dominant mode of the heat transfer

  10. Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

    2012-04-11

    A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling

  11. Thermal-economic optimisation of a CHP gas turbine system by applying a fit-problem genetic algorithm

    Science.gov (United States)

    Ferreira, Ana C. M.; Teixeira, Senhorinha F. C. F.; Silva, Rui G.; Silva, Ângela M.

    2018-04-01

    Cogeneration allows the optimal use of the primary energy sources and significant reductions in carbon emissions. Its use has great potential for applications in the residential sector. This study aims to develop a methodology for thermal-economic optimisation of small-scale micro-gas turbine for cogeneration purposes, able to fulfil domestic energy needs with a thermal power out of 125 kW. A constrained non-linear optimisation model was built. The objective function is the maximisation of the annual worth from the combined heat and power, representing the balance between the annual incomes and the expenditures subject to physical and economic constraints. A genetic algorithm coded in the java programming language was developed. An optimal micro-gas turbine able to produce 103.5 kW of electrical power with a positive annual profit (i.e. 11,925 €/year) was disclosed. The investment can be recovered in 4 years and 9 months, which is less than half of system lifetime expectancy.

  12. Post-Accident Waste Management in Ukraine : Challenges and Steps Needed to Resolve the Accident Waste Problem

    International Nuclear Information System (INIS)

    Kilochytska, T.; Zinkevich, L.; Shybetskyi, I.; Krone, J.

    2016-01-01

    Conclusions: • Solving the problem of management of “Chernobyl waste” requires: - a systematic review of the existing norms and regulations with respect to best international practice of radioactive waste management; - improvement of the existing classification / characterization of radioactive waste with a focus on disposal; - improvement of the safety assessment approaches for licensing the disposal of accident waste, taking into account relevant safety features and site specific conditions; - involving of international experience and support to plan and perform safety related activity on the Shelter Object transformation

  13. The learning potentials and challenges when integrating Web 2.0 in a problem-based learning approach

    DEFF Research Database (Denmark)

    Buus, Lillian

    The research makes a triple co-construction between problem-based learning (PBL), learning design and action research within the area of networked learning. The complexity this creates in the research can lead it in many different directions, because it builds on collaboration, interaction...... and “elements” in motion. The authors' assumption is built on the perspective that knowledge is constructed in social collaborative interactions between people. Furthermore, she claims that the ideology of Web 2.0 provides research opportunities to study phenomena also found in PBL and networked learning...

  14. The Formation of the Urban Environment in the West Siberian Oil and Gas Region: Problems and Challenges

    Science.gov (United States)

    Bauer, N. V.; Speranskaya, N. I.; Shabatura, L. N.; Iatsevich, O. E.

    2016-10-01

    The article deals with the problems faced by the person in relation to the culture of creating a sustainable urban environment. The urban environment is seen as space of human existence, influencing its spiritual and physical health. All the experts involved in the urban environment, think about the culture of its formation, unfortunately, only from a departmental point of view. Differently organized human environment inevitably affects behavior, emotional state of a man, his perception and understanding of space. The cultural heritage of society fits in the space of an artificial environment created by a man, and determines the behavior of people.For the solution of problems of formation of the urban environment, it is necessary to apply a set of interrelated technical, social, environmental, aesthetic and other measures. In this capacity, landscape design as a set of methods has to build a sustainable urban environment to ensure harmonious living.Current trends, methods, and techniques of landscape design are to create sustainable environment for a person - creative, spiritual, comfortable, attractive, safe, harmonious.

  15. Contribution to solving the problem of neutron thermalization in heterogeneous reactor; Prilog resavanju problema termalizacije neutron u heterognom reaktoru

    Energy Technology Data Exchange (ETDEWEB)

    Pop-Jordanov, J P [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1963-12-15

    A method for calculating of neutron termalization in heterogeneous rector core was developed. It is more precise than the diffusion method but more complcated. Concerning accuracy it is comparable to non-diffusion methods. Sonce the approach was analytical need for powerful computer is avoided and the description of physical phenomena is more transparent. Convergence is satsfactory. Constraints of the proposed method are: low neutron absorption in the moderator, negligible slowing down in the fuel, and big lattice pitch. The method is applicable for heavy water and graphite moderator systems. Based on the application of this method, procedures were developed for calculating thermal utilzation and neutron temperature. Since 1/v dependence of cross sections is not estimated this metof could be used for long-term reactivity changes.

  16. Challenges and opportunities in coding the commons: problems, procedures, and potential solutions in large-N comparative case studies

    Directory of Open Access Journals (Sweden)

    Elicia Ratajczyk

    2016-09-01

    Full Text Available On-going efforts to understand the dynamics of coupled social-ecological (or more broadly, coupled infrastructure systems and common pool resources have led to the generation of numerous datasets based on a large number of case studies. This data has facilitated the identification of important factors and fundamental principles which increase our understanding of such complex systems. However, the data at our disposal are often not easily comparable, have limited scope and scale, and are based on disparate underlying frameworks inhibiting synthesis, meta-analysis, and the validation of findings. Research efforts are further hampered when case inclusion criteria, variable definitions, coding schema, and inter-coder reliability testing are not made explicit in the presentation of research and shared among the research community. This paper first outlines challenges experienced by researchers engaged in a large-scale coding project; then highlights valuable lessons learned; and finally discusses opportunities for further research on comparative case study analysis focusing on social-ecological systems and common pool resources.

  17. Thermal Conductivity of Diamond Composites

    Directory of Open Access Journals (Sweden)

    Fedor M. Shakhov

    2009-12-01

    Full Text Available A major problem challenging specialists in present-day materials sciences is the development of compact, cheap to fabricate heat sinks for electronic devices, primarily for computer processors, semiconductor lasers, high-power microchips, and electronics components. The materials currently used for heat sinks of such devices are aluminum and copper, with thermal conductivities of about 250 W/(m·K and 400 W/(m·K, respectively. Significantly, the thermal expansion coefficient of metals differs markedly from those of the materials employed in semiconductor electronics (mostly silicon; one should add here the low electrical resistivity metals possess. By contrast, natural single-crystal diamond is known to feature the highest thermal conductivity of all the bulk materials studied thus far, as high as 2,200 W/(m·K. Needless to say, it cannot be applied in heat removal technology because of high cost. Recently, SiC- and AlN-based ceramics have started enjoying wide use as heat sink materials; the thermal conductivity of such composites, however, is inferior to that of metals by nearly a factor two. This prompts a challenging scientific problem to develop diamond-based composites with thermal characteristics superior to those of aluminum and copper, adjustable thermal expansion coefficient, low electrical conductivity and a moderate cost, below that of the natural single-crystal diamond. The present review addresses this problem and appraises the results reached by now in studying the possibility of developing composites in diamond-containing systems with a view of obtaining materials with a high thermal conductivity.

  18. Problem trap final repository. Social challenges concerning nuclear waste; Problemfalle Endlager. Gesellschaftliche Herausforderungen im Umgang mit Atommuell

    Energy Technology Data Exchange (ETDEWEB)

    Brunnengraeber, Achim (ed.)

    2016-07-01

    How is it possible that there is still no final storage facility in the entire world for highly radioactive waste from nuclear power stations? How is it possible that electricity has been generated by industrial-scale nuclear installations for decades without the issue of the disposal of nuclear waste having been resolved? The events in Chernobyl in 1986 and Fukushima in 2011 have made it blatantly obvious how risky this technology is and how important it is to keep humans and the environment at a safe distance from radioactivity. This anthology examines the technological, political, social and economic dimensions of the permanent disposal of nuclear waste. It provides an insight into the emergence of the problem and the people involved and their interests. It describes and analyses the changes that are taking place in Germany (for instance, in relation to the government's commission on nuclear repositories) and other countries with regard to how they handle nuclear waste. The book deals with both questions related to socio-technical aspects of the permanent disposal of nuclear waste and calls for the democratic need for participation and new ways of doing so, without which the search for a permanent disposal site will not bear fruit. This anthology presents a comprehensive discussion of the disposal of nuclear waste and the search for a permanent repository for it. Not only will students and teachers find it extremely useful, but so will any readers who are interested in its subject matter and wish to gain a more in-depth insight into it.

  19. The Pitt Innovation Challenge (PInCh): Driving Innovation in Translational Research Through an Incentive-Based, Problem-Focused Competition.

    Science.gov (United States)

    Fitzpatrick, Nicole Edgar; Maier, John; Yasko, Laurel; Mathias, David; Qua, Kacy; Wagner, Erika; Miller, Elizabeth; Reis, Steven E

    2017-05-01

    Translational research aims to move scientific discoveries across the biomedical spectrum from the laboratory to humans, and to ultimately transform clinical practice and public health policies. Despite efforts to accelerate translational research through national initiatives, several major hurdles remain. The authors created the Pitt Innovation Challenge (PInCh) as an incentive-based, problem-focused approach to solving identified clinical or public health problems at the University of Pittsburgh Clinical and Translational Science Institute in spring 2014. With input from a broad range of stakeholders, PInCh leadership arrived at the challenge question: How do we empower individuals to take control of their own health outcomes? The authors developed the PInCh's three-round proposal submission and review process as well as an online contest management tool to support the process. Ninety-two teams submitted video proposals in round one. Proposals included mobile applications (29; 32%), other information technology (19; 21%), and community program (22; 24%) solutions. Ten teams advanced to the final round, where three were awarded $100,000 to implement their solution over 12 months. In a 6-month follow-up survey, 6/11 (55%) team leaders stated the PInCh helped to facilitate connections outside their normal sphere of collaborators. Additional educational training sessions related to problem-focused research will be developed. The PInCh will be expanded to engage investment and industry communities to facilitate the translation of solutions to clinical practice via commercialization pathways. External organizations and other universities will be engaged to use the PInCh as a mechanism to fuel innovation in their spaces.

  20. Vacuum systems - thermal issues

    International Nuclear Information System (INIS)

    Howell, J.W.

    1992-01-01

    The new high-energy synchrotron light sources currently under construction and the B-factories that are still in the planning stage present new challenges in the management of synchrotron radiation thermal loading. With particle energies from 6 to 9 GeV and currents from 0.3 to 2.5 mA, the total power and the power density of the resulting synchrotron radiation each present unique problems. The design issues involved in managing these new power levels are presented, as well as a survey of some of the proposed design solutions

  1. Problems and challenges in the development and validation of human cell-based assays to determine nanoparticle-induced immunomodulatory effects

    Directory of Open Access Journals (Sweden)

    Rossi François

    2011-02-01

    Full Text Available Abstract Background With the increasing use of nanomaterials, the need for methods and assays to examine their immunosafety is becoming urgent, in particular for nanomaterials that are deliberately administered to human subjects (as in the case of nanomedicines. To obtain reliable results, standardised in vitro immunotoxicological tests should be used to determine the effects of engineered nanoparticles on human immune responses. However, before assays can be standardised, it is important that suitable methods are established and validated. Results In a collaborative work between European laboratories, existing immunological and toxicological in vitro assays were tested and compared for their suitability to test effects of nanoparticles on immune responses. The prototypical nanoparticles used were metal (oxide particles, either custom-generated by wet synthesis or commercially available as powders. Several problems and challenges were encountered during assay validation, ranging from particle agglomeration in biological media and optical interference with assay systems, to chemical immunotoxicity of solvents and contamination with endotoxin. Conclusion The problems that were encountered in the immunological assay systems used in this study, such as chemical or endotoxin contamination and optical interference caused by the dense material, significantly affected the data obtained. These problems have to be solved to enable the development of reliable assays for the assessment of nano-immunosafety.

  2. Physiological benefits of being small in a changing world: responses of Coho salmon (Oncorhynchus kisutch to an acute thermal challenge and a simulated capture event.

    Directory of Open Access Journals (Sweden)

    Timothy D Clark

    Full Text Available Evidence is building to suggest that both chronic and acute warm temperature exposure, as well as other anthropogenic perturbations, may select for small adult fish within a species. To shed light on this phenomenon, we investigated physiological and anatomical attributes associated with size-specific responses to an acute thermal challenge and a fisheries capture simulation (exercise+air exposure in maturing male coho salmon (Oncorhynchus kisutch. Full-size females were included for a sex-specific comparison. A size-specific response in haematology to an acute thermal challenge (from 7 to 20 °C at 3 °C h(-1 was apparent only for plasma potassium, whereby full-size males exhibited a significant increase in comparison with smaller males ('jacks'. Full-size females exhibited an elevated blood stress response in comparison with full-size males. Metabolic recovery following exhaustive exercise at 7 °C was size-specific, with jacks regaining resting levels of metabolism at 9.3 ± 0.5 h post-exercise in comparison with 12.3 ± 0.4 h for full-size fish of both sexes. Excess post-exercise oxygen consumption scaled with body mass in male fish with an exponent of b = 1.20 ± 0.08. Jacks appeared to regain osmoregulatory homeostasis faster than full-size males, and they had higher ventilation rates at 1 h post-exercise. Peak metabolic rate during post-exercise recovery scaled with body mass with an exponent of b~1, suggesting that the slower metabolic recovery in large fish was not due to limitations in diffusive or convective oxygen transport, but that large fish simply accumulated a greater 'oxygen debt' that took longer to pay back at the size-independent peak metabolic rate of ~6 mg min(-1 kg(-1. Post-exercise recovery of plasma testosterone was faster in jacks compared with full-size males, suggesting less impairment of the maturation trajectory of smaller fish. Supporting previous studies, these findings suggest that environmental change and non

  3. International Conference on Microtechnology and Thermal Problems in Electronics (MicroTherm'2015) and International Conference on Smart Engineering of New Materials (SENM'2015)

    International Nuclear Information System (INIS)

    2016-01-01

    The issue covers selected papers presented during the Joint Event of two International Cyclic Conferences: MicroTherm – Microtechnology and Thermal Problems in Electronics and SENM – Smart Engineering of New Materials. The Duoconference was held in Lodz, Poland on 23-25 June 2015. It gathered almost 200 participants from 20 countries. MicroTherm is an International Conference on Microtechnology and Thermal Problems in Electronics that is organised every two years, since 1996. The success of the first seminar devoted to thermal management aspects, and the successive conferences have led us to the eleventh edition. Since the first meeting, the scope of the Conference has expanded, following the progress of electronics. Now, it covers subjects connected with extreme temperature, electronics, sensors and measurement techniques, modelling, simulation, wide band-gap materials, packaging and reliability, renewable energy sources and photonics with special emphasis on microelectronic technologies. The tradition of SENM dates back to 1985 when the First International Conference on Diamond Crystallization under Reduced Pressure was held in Jabłonna, Poland. Since then, the Conference is organised regularly every five years. From the early beginning the main aim of this event was the creation of an international forum of scientists for the presentation of the newest achievements and investigation results in vacuum and plasma techniques, synthesis, characterisation and application of diamond, its derivatives and other wide bandgap materials. Over time, the scope of the conference has expanded to include nanomaterials, biomaterials and new functional materials, in the range of production, design and optimisation of the synthesis and modification technologies. Traditionally, the programme of MicroTherm’2015 and SENM’2015 is comprised of invited talks and regular sessions in the form of planar discussions and poster presentations, which also include a Students’ Session

  4. Veterinarian challenges to providing a multi-agency response to farm animal welfare problems in Ireland: responding to the human factor.

    Science.gov (United States)

    Devitt, C; Kelly, P; Blake, M; Hanlon, A; More, S J

    2013-12-01

    In 2012, the authors undertook a study of the challenges facing government and private veterinarians in responding to the human element of farm animal welfare incidents (i.e. the personal problems and difficulties of farmers that can result in farm animal neglect). This paper reports their findings and examines the role of veterinarians in responding to the difficulties of farmers. It also looks at their experiences of attempting to build a multi-agency approach involving veterinary and human support services. This paper builds on a study whereby the authors considered how social, health and attitudinal factors, as well as mental health problems, contribute to farm animal welfare incidents in Ireland. An early warning system involving relevant agencies is in place to identify and prevent farm animal welfare problems before they become critical. The literature provides examples of private veterinarians combining with support services where there are indicators of animal and human abuse. Yet there are no research examples of government or private veterinarians linking with support services to resolve farm animal welfare cases where there are social, health, and/or mental health difficulties with the herd owner. Four focus groups were conducted with government veterinarians (n = 18) and three with private veterinarians (n = 12). Government veterinarians made contact with support services to seek advice on how best to respond to the human element of farm animal welfare incidents, and/or to seek support for the herd owner. Contact between government and private veterinarians was driven by the former. Communication between agencies was influenced by individual efforts and personal contacts. Formal structures and guidelines, perceived professional capabilities in determining herd owner needs, and client confidentiality concerns among support services and private veterinarians were less influential. The fear of losing clients and the financial implications of this were

  5. Mercury emissions from flooded soils and sediments in Germany are an underestimated problem: challenges for reliable risk assessments and management strategies

    Directory of Open Access Journals (Sweden)

    Rinklebe J.

    2013-04-01

    -polluted floodplain soils in Germany and that those emissions are an underestimated problem. Current needs for reliable risk assessments, the induced implications for authorities, and future challenges will be discussed. The presented data will contribute to a better understanding of seasonal dynamics of Hg fluxes and its controlling factors. This presentation should be of large interest for a wide international audience, such as environmental scientists and managers, applied ecologists, and authorities.

  6. Theory of thermal stresses

    CERN Document Server

    Boley, Bruno A

    1997-01-01

    Highly regarded text presents detailed discussion of fundamental aspects of theory, background, problems with detailed solutions. Basics of thermoelasticity, heat transfer theory, thermal stress analysis, more. 1985 edition.

  7. Controlling Thermal Expansion: A Metal?Organic Frameworks Route

    OpenAIRE

    Balestra, Salvador R. G.; Bueno-Perez, Rocio; Hamad, Said; Dubbeldam, David; Ruiz-Salvador, A. Rabdel; Calero, Sofia

    2016-01-01

    Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal?organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model m...

  8. SPAR thermal analysis processors reference manual, system level 16. Volume 1: Program executive. Volume 2: Theory. Volume 3: Demonstration problems. Volume 4: Experimental thermal element capability. Volume 5: Programmer reference

    Science.gov (United States)

    Marlowe, M. B.; Moore, R. A.; Whetstone, W. D.

    1979-01-01

    User instructions are given for performing linear and nonlinear steady state and transient thermal analyses with SPAR thermal analysis processors TGEO, SSTA, and TRTA. It is assumed that the user is familiar with basic SPAR operations and basic heat transfer theory.

  9. Certification of forests and wood products in Serbia in the context of new European union legislations: Current situation, problems and challenges

    Directory of Open Access Journals (Sweden)

    Vasiljević Aleksandar

    2011-01-01

    Full Text Available The paper presents research results of the current situation in the area of certification of forests and wood products in Serbia in the context of new European Union legislation referring to the placement of wood and wood products on this market. The objective of the research was to observe the situation, phases which Serbia implemented in the process of forest and wood products certification until now, as well as the problems and challenges the companies in this process face. Based on research results, future development of the market of certified wood products in Serbia was assessed and the proposal of measures which should be realized in order for Serbia to become a country whose companies will be ready for the moment when provisions and measures of the new EU legislation become effective was given. The selection of the abovementioned objective was conditioned by the fact that from January 1st, 2013 new legislation takes effect, with significantly stricter terms for the placement of wood and wood products from other countries on this market. One of the conditions which will have to be fulfilled by the companies wishing to export their products on this market refers to proving their origin. Since the EU is the most significant market for wood products exported from Serbia, fulfillment of the stated and other terms from the new EU legislation is of great importance to Serbian companies. Until the beginning of September 2010, only 387,000 ha were certified, namely 17.2% of the total area under forests. In the same period, only 33 wood processing companies in Serbia possessed CoC certificates for their products. Such a small number of companies possessing certificates for their wood products compared to competitive neighboring countries can represent a serious limitation in achieving their satisfactory competitiveness on the EU market in the following period.

  10. Parallel thermal radiation transport in two dimensions

    International Nuclear Information System (INIS)

    Smedley-Stevenson, R.P.; Ball, S.R.

    2003-01-01

    This paper describes the distributed memory parallel implementation of a deterministic thermal radiation transport algorithm in a 2-dimensional ALE hydrodynamics code. The parallel algorithm consists of a variety of components which are combined in order to produce a state of the art computational capability, capable of solving large thermal radiation transport problems using Blue-Oak, the 3 Tera-Flop MPP (massive parallel processors) computing facility at AWE (United Kingdom). Particular aspects of the parallel algorithm are described together with examples of the performance on some challenging applications. (author)

  11. Parallel thermal radiation transport in two dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Smedley-Stevenson, R.P.; Ball, S.R. [AWE Aldermaston (United Kingdom)

    2003-07-01

    This paper describes the distributed memory parallel implementation of a deterministic thermal radiation transport algorithm in a 2-dimensional ALE hydrodynamics code. The parallel algorithm consists of a variety of components which are combined in order to produce a state of the art computational capability, capable of solving large thermal radiation transport problems using Blue-Oak, the 3 Tera-Flop MPP (massive parallel processors) computing facility at AWE (United Kingdom). Particular aspects of the parallel algorithm are described together with examples of the performance on some challenging applications. (author)

  12. Thermal energy accumulators. A bibliographical study

    International Nuclear Information System (INIS)

    Charlety, Paul

    1971-01-01

    Energy storage is a challenge, notably for spacecraft, submarines and non-polluting automotive vehicles. After a comparison of mass energies of different principles of energy accumulation (magnetic, electrostatic, solid elasticity, kinetic energy, gaseous elasticity, electro-chemistry, sensitive heat, freezing heat, fuels, radioactivity, nuclear fission or fusion, mass energy), the author discusses the choice of thermal storage, presents the main bodies used for thermal energy accumulation (molten salts such as lithium hydride or lithium salt eutectics, or other compounds such as alumina, paraffins), and gives an overview of the main theoretical problems [fr

  13. Principles of Positive Behaviour Supports: Using the FBA as a Problem-Solving Approach to Address Challenging Behaviours beyond Special Populations

    Science.gov (United States)

    Moreno, Gerardo; Bullock, Lyndal M.

    2011-01-01

    The Functional Behavioural Assessment (FBA) is an investigative process that examines the context of challenging behaviours in the classroom. Information gleaned from the FBA process is used to develop a behaviour intervention plan to address the challenging behaviour and teach a socially acceptable replacement behaviour. However, the FBA has…

  14. Apollo telescope mount thermal systems unit thermal vacuum test

    Science.gov (United States)

    Trucks, H. F.; Hueter, U.; Wise, J. H.; Bachtel, F. D.

    1971-01-01

    The Apollo Telescope Mount's thermal systems unit was utilized to conduct a full-scale thermal vacuum test to verify the thermal design and the analytical techniques used to develop the thermal mathematical models. Thermal vacuum test philosophy, test objectives configuration, test monitoring, environment simulation, vehicle test performance, and data correlation are discussed. Emphasis is placed on planning and execution of the thermal vacuum test with particular attention on problems encountered in conducting a test of this maguitude.

  15. The ITER project technological challenges

    CERN Multimedia

    CERN. Geneva; Lister, Joseph; Marquina, Miguel A; Todesco, Ezio

    2005-01-01

    The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the designer approach and the available technologies are critically discussed. The fourth lecture is devoted to the issue of performance prediction, from a superconducting wire to a large size conductor. The role of scaling laws, self-field, current distribution, voltage-current characteristic and transposition are...

  16. The lesser known challenge of climate change: thermal variance and sex-reversal in vertebrates with temperature-dependent sex determination.

    Directory of Open Access Journals (Sweden)

    Jennifer L Neuwald

    Full Text Available Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD, as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change.

  17. The Algebra Teacher's Activity-a-Day, Grades 6-12 Over 180 Quick Challenges for Developing Math and Problem-Solving Skills

    CERN Document Server

    Thompson, Frances McBroom

    2010-01-01

    Fun-filled math problems that put the emphasis on problem-solving strategies and reasoning. The Algebra Teacher's Activity-a-Day offers activities for test prep, warm-ups, down time, homework, or just for fun. These unique activities are correlated with national math education standards and emphasize problem-solving strategies and logical reasoning skills. In many of the activities, students are encouraged to communicate their different approaches to other students in the class.: Filled with dozens of quick and fun algebra activities that can be used inside and outside the classroom; Designed

  18. Compliance of Bombardier's Challenger 604 and CRJ200 to FAR25.856(a) : flame propagation of thermal/acoustic insulation materials and future trends in aircraft materials fire safety

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W.R. [Bombardier, Montreal, PQ (Canada); Schofield, C.M.A. [Transport Canada, Ottawa, ON (Canada)

    2007-07-01

    This paper provided details of a testing program designed to ensure the compliance of Bombardier's Challenger 604 to new rules established to improve flammability standards for thermal and acoustic insulation materials. The rule applied to both pressurized and unpressurized sections of the fuselage, as well as to ducting, sound damping foams, and insulation bags. Test samples of all non-metallic insulation components were collected. Testing of the samples was conducted in a chamber with an ignition source as well as a controlled heat flux provided by a radiant panel. The new rules were discussed as well as challenges faced by industry which will have to show compliance for flame propagation requirements. Issues related to the in-service replacement of thermal and acoustic insulation materials were reviewed along with potential changes to flammability regulations. Materials used by Bombardier for compliant constructions were also listed. It was concluded that the safety of airplane occupants will be improved through compliance to new testing methods under harsher fire threat conditions, with more stringent pass and fail criteria. 15 refs., 5 figs.

  19. Global challenges

    International Nuclear Information System (INIS)

    Blix, H.

    1990-01-01

    A major challenge now facing the world is the supply of energy needed for growth and development in a manner which is not only economically viable but also environmentally acceptable and sustainable in view of the demands of and risks to future generations. The internationally most significant pollutants from energy production through fossil fuels are SO 2 and NO x which cause acid rain, and CO 2 which is the most significant contributor to the greenhouse effect. Nuclear power, now providing about 17% of the world's electricity and 5% of the primary energy already is making a notable contribution to avoiding these emissions. While the industrialized countries will need more energy and especially electricity in the future, the needs of the developing countries are naturally much larger and present a tremendous challenge to the shaping of the world's future energy supply system. The advanced countries will have to accept special responsibilities, as they can most easily use advanced technologies and they have been and remain the main contributors to the environmental problems we now face. Energy conservation and resort to new renewable energy sources, though highly desirable, appear inadequate alone to meet the challenges. The world can hardly afford to do without an increased use of nuclear power, although it is strongly contested in many countries. The objections raised against the nuclear option focus on safety, waste management and disposal problems and the risk for proliferation of nuclear weapons. These issues are not without their problems. The risk of proliferation exists but will not appreciably diminish with lesser global reliance on nuclear power. The waste issue is more of a political than a technical problem. The use of nuclear power, or any other energy source, will never be at zero risk, but the risks are constantly reduced by new techniques and practices. The IAEA sees it as one of its priority tasks to promote such techniques. (author)

  20. Ultra-fast photo-patterning of hydroxamic acid layers adsorbed on TiAlN: The challenge of modeling thermally induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Hemgesberg, Maximilian [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany); Schuetz, Simon [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Heidelberger Druckmaschinen AG, Kurfuerstenanlage 54-60, 66120 Heidelberg (Germany); Mueller, Christine [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Schloerholz, Matthias; Latzel, Harald [Heidelberger Druckmaschinen AG, Kurfuerstenanlage 54-60, 66120 Heidelberg (Germany); Sun, Yu [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany); Ziegler, Christiane [Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 45, 67663 Kaiserslautern (Germany); Thiel, Werner R., E-mail: thiel@chemie.uni-kl.de [Fachbereich Chemie, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 54, 67663 Kaiserslautern (Germany)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Different hydroxamic acids are suitable for the hydrophobization of TiAlN surfaces used in photo-patterning applications. Black-Right-Pointing-Pointer The binding strength of the surfactant on the surface is dependent on the hydrogen and {pi}-bonding interactions within the organic layer. Black-Right-Pointing-Pointer Thermal desorption of selected HA species results in a 20% energy reduction compared to alkyl phosphates. - Abstract: Long-chain n-alkyl terminated hydroxamic acids (HA) are used for the modification of titanium aluminum nitride (TiAlN) surfaces. HA coatings improve the hydrophobicity of this wear resistant and industrially relevant ceramic. Therefore, HAs with different structural properties are evaluated with respect to their wear resistance and their thermal desorption properties. In order to find new coatings for rewritable offset printing plates, the changes in the surface polarity, composition, and morphology are analyzed by contact angle measurements, X-ray photoemission spectroscopy (XPS), and scanning force microscopy (SFM), respectively. The results are referenced to the strongly bonding molecule n-dodecyl phosphonate (PO11M), which has been used for surface hydrophobization before but proved difficult to remove due to the high laser outputs required for thermal desorption. It is found that for certain HAs, an equally good hydrophobization compared to PO11M can be achieved. Contact angles obtained for different hydroxamic acid coatings can be correlated to their modes of adsorption. Only for selected HA species, resistance to mechanical wear is sufficient for further investigations. Photo-patterning of these hydroxamic acid layers is achieved using a high energy IR laser beam at different energy inputs. Fitting of the obtained data and further evaluation using finite element analysis (FEM) calculations reveal significantly reduced energy consumption of about 20% for the removal of a specific hydroxamic

  1. Solving the problems we face: the United States Environmental Protection Agency, sustainability, and the challenges of the twenty-first century

    Science.gov (United States)

    Addressing the problems of the twenty-first century will require new initiatives that complement traditional regulatory activities. Existing regulations, such as the Clean Air Act and Clean Water Act are important safety nets in the United States for protecting human health and t...

  2. Integrated Cognitive-neuroscience Architectures for Understanding Sensemaking (ICArUS): A Computational Basis for ICArUS Challenge Problem Design

    Science.gov (United States)

    2014-11-01

    Critical Thinking with Bayesian HELP Storytelling is a powerful device, widely used for organizational learning and personnel training. But a problem... advertisements : A Bayesian model of Burma-Shave’s muse. Artificial Intelligence for Engineering Design, Analysis and Manufacturing. Burns, K. (2014). ICArUS

  3. Diagnosing plant problems

    Science.gov (United States)

    Cheryl A. Smith

    2008-01-01

    Diagnosing Christmas tree problems can be a challenge, requiring a basic knowledge of plant culture and physiology, the effect of environmental influences on plant health, and the ability to identify the possible causes of plant problems. Developing a solution or remedy to the problem depends on a proper diagnosis, a process that requires recognition of a problem and...

  4. Survey of thermal insulation systems

    International Nuclear Information System (INIS)

    Kinoshita, Izumi

    1983-01-01

    Better thermal insulations have been developed to meet the growing demands of industry, and studies on thermal insulation at both high temperature and low temperature have been widely performed. The purpose of this survey is to summarize data on the performances and characteristics of thermal insulation materials and thermal insulation structures (for instance, gas cooled reactors, space vehicles and LNG storage tanks), and to discuss ravious problems regarding the design of thermal insulation structures of pool-type LMFBRs. (author)

  5. Thermal explosion models

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Tso Chin [Malaya Univ., Kuala Lumpur (Malaysia)

    1984-12-01

    The phenomenon of thermal explosion arises in several important safety problems, yet scientists are still baffled by its origin. This article reviews some of the models that have been proposed to explain the phenomenon.

  6. Thermal explosion models

    International Nuclear Information System (INIS)

    Tso Chin Ping

    1984-01-01

    The phenomenon of thermal explosion arises in several important safety problems, yet scientists are still baffled by its origin. This article reviews some of the models that have been proposed to explain the phenomenon. (author)

  7. Conceptual thermal design

    NARCIS (Netherlands)

    Strijk, R.

    2008-01-01

    Present thermal design tools and methods insufficiently support the development of structural concepts engaged by typical practicing designers. Research described in this thesis identifies the main thermal design problems in practice. In addition, models and methods are developed that support an

  8. Thermal boundary condition effects on forced convection heat transfer. Application of a numerical solution of an adjoint problem; Kyosei tairyu netsudentatsu mondai ni okeru netsuteki kyokai joken no eikyo. Zuihan mondai no suchi kai wo mochiita kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Momose, K.; Saso, K.; Kimoto, H. [Osaka University, Osaka (Japan). Faculty of Engineering Science

    1997-11-25

    We propose a numerical solution for the adjoint operator of a forced convection heat transfer problem to evaluate mean heat transfer characteristics under arbitrary thermal conditions. Using the numerical solutions of the adjoint problems under Dirichlet and Neumann conditions, both of which can be computed using a conventional CFD code, the influence function of the local surface temperature on the total heat transfer and that of the local surface heat flux on the mean surface temperature are obtained. As a result, the total heat fluxes for arbitrary surface temperature distributions and the mean surface temperatures for arbitrary surface heat flux distributions can be calculated using these influence functions. The influence functions for a circular cylinder and for an in-line square rod array are presented. 14 refs., 9 figs., 1 tab.

  9. Knapsack problems

    CERN Document Server

    Kellerer, Hans; Pisinger, David

    2004-01-01

    Thirteen years have passed since the seminal book on knapsack problems by Martello and Toth appeared. On this occasion a former colleague exclaimed back in 1990: "How can you write 250 pages on the knapsack problem?" Indeed, the definition of the knapsack problem is easily understood even by a non-expert who will not suspect the presence of challenging research topics in this area at the first glance. However, in the last decade a large number of research publications contributed new results for the knapsack problem in all areas of interest such as exact algorithms, heuristics and approximation schemes. Moreover, the extension of the knapsack problem to higher dimensions both in the number of constraints and in the num­ ber of knapsacks, as well as the modification of the problem structure concerning the available item set and the objective function, leads to a number of interesting variations of practical relevance which were the subject of intensive research during the last few years. Hence, two years ago ...

  10. Timelike and null focusing singularities in spherical symmetry: A solution to the cosmological horizon problem and a challenge to the cosmic censorship hypothesis

    International Nuclear Information System (INIS)

    Celerier, Marie-Noeelle; Szekeres, Peter

    2002-01-01

    Extending the study of spherically symmetric metrics satisfying the dominant energy condition and exhibiting singularities of power-law type initiated by Szekeres and Iyer, we identify two classes of peculiar interest: focusing timelike singularity solutions with the stress-energy tensor of a radiative perfect fluid (equation of state: p=(1/3)ρ) and a set of null singularity classes verifying identical properties. We consider two important applications of these results: to cosmology, as regards the possibility of solving the horizon problem with no need to resort to any inflationary scenario, and to the strong cosmic censorship hypothesis to which we propose a class of physically consistent counterexamples

  11. Children's mental health emergencies-part 1: challenges in care: definition of the problem, barriers to care, screening, advocacy, and resources.

    Science.gov (United States)

    Baren, Jill M; Mace, Sharon E; Hendry, Phyllis L; Dietrich, Ann M; Grupp-Phelan, Jacqueline; Mullin, Jacqueline

    2008-06-01

    At a time when there has been a reduction in mental health resources nationwide, the incidence of mental health disorders in children has seen a dramatic increase for many reasons. A review of the literature was done to identify the epidemiology, barriers to care, useful emergency department (ED) screening methods, and resources regarding pediatric mental health disorders in the ED. Although there are many challenges to the provision of care for children with mental health emergencies, some resources are available. Furthermore, ED screening and intervention may be effective in improving patient outcomes. Collaborative efforts with multidisciplinary services can create a continuum of care, promote better identification of children and adolescents with mental health disorders, and promote early recognition and intervention, which are key to effective referral and treatment.

  12. Dynamic thermal environment and thermal comfort.

    Science.gov (United States)

    Zhu, Y; Ouyang, Q; Cao, B; Zhou, X; Yu, J

    2016-02-01

    Research has shown that a stable thermal environment with tight temperature control cannot bring occupants more thermal comfort. Instead, such an environment will incur higher energy costs and produce greater CO2 emissions. Furthermore, this may lead to the degeneration of occupants' inherent ability to combat thermal stress, thereby weakening thermal adaptability. Measured data from many field investigations have shown that the human body has a higher acceptance to the thermal environment in free-running buildings than to that in air-conditioned buildings with similar average parameters. In naturally ventilated environments, occupants have reported superior thermal comfort votes and much greater thermal comfort temperature ranges compared to air-conditioned environments. This phenomenon is an integral part of the adaptive thermal comfort model. In addition, climate chamber experiments have proven that people prefer natural wind to mechanical wind in warm conditions; in other words, dynamic airflow can provide a superior cooling effect. However, these findings also indicate that significant questions related to thermal comfort remain unanswered. For example, what is the cause of these phenomena? How we can build a comfortable and healthy indoor environment for human beings? This article summarizes a series of research achievements in recent decades, tries to address some of these unanswered questions, and attempts to summarize certain problems for future research. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. CHALLENGING PROBLEMS OF HYPERTENSION MANAGEMENT: THE EFFECT OF INCREASED HEART RATE AND COMORBIDITIES ON THE CHOICE OF ANTIHYPERTENSIVE THERAPY IN PRACTICE OF CARDIOLOGIST AND THERAPIST. The Conclusion of the Expert Council

    Directory of Open Access Journals (Sweden)

    G. P. Arutyunov

    2015-09-01

    Full Text Available The conclusion of the Expert Council "Challenging problems of hypertension management: the effect of increased heart rate and comorbidities on the choice of antihypertensive therapy in practice of cardiologist and therapist" is presented. Topical issues of hypertensive patient’s treatment, the role of heart rate in hypertension and ways to influence it are considered. The possibility of treatment of hypertensive patients with trandolapril/verapamil SR fixed combination is analyzed separately. The data on the clinical efficacy and protective effects of trandolapril/verapamil SR fixed combination are presented.

  14. Coal-water slurries containing petrochemicals to solve problems of air pollution by coal thermal power stations and boiler plants: An introductory review.

    Science.gov (United States)

    Dmitrienko, Margarita A; Strizhak, Pavel A

    2018-02-01

    This introductory study presents the analysis of the environmental, economic and energy performance indicators of burning high-potential coal water slurries containing petrochemicals (CWSP) instead of coal, fuel oil, and natural gas at typical thermal power stations (TPS) and a boiler plant. We focus on the most hazardous anthropogenic emissions of coal power industry: sulfur and nitrogen oxides. The research findings show that these emissions may be several times lower if coal and oil processing wastes are mixed with water as compared to the combustion of traditional pulverized coal, even of high grades. The study focuses on wastes, such as filter cakes, oil sludge, waste industrial oils, heavy coal-tar products, resins, etc., that are produced and stored in abundance. Their deep conversion is very rare due to low economic benefit. Effective ways are necessary to recover such industrial wastes. We present the cost assessment of the changes to the heat and power generation technologies that are required from typical power plants for switching from coal, fuel oil and natural gas to CWSPs based on coal and oil processing wastes. The corresponding technological changes pay off after a short time, ranging from several months to several years. The most promising components for CWSP production have been identified, which provide payback within a year. Among these are filter cakes (coal processing wastes), which are produced as a ready-made coal-water slurry fuel (a mixture of flocculants, water, and fine coal dust). These fuels have the least impact on the environment in terms of the emissions of sulfur and nitrogen oxides as well as fly ash. An important conclusion of the study is that using CWSPs based on filter cakes is worthwhile both as the main fuel for thermal power stations and boiler plants and as starting fuel. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Strategies for the Assessment of Metabolic Profiles of Steroid Hormones in View of Diagnostics and Drug Monitoring: Analytical Problems and Challenges.

    Science.gov (United States)

    Plenis, Alina; Oledzka, Ilona; Kowalski, Piotr; Baczek, Tomasz

    2016-01-01

    During the last few years there has been a growing interest in research focused on the metabolism of steroid hormones despite that the study of metabolic hormone pathways is still a difficult and demanding task because of low steroid concentrations and a complexity of the analysed matrices. Thus, there has been an increasing interest in the development of new, more selective and sensitive methods for monitoring these compounds in biological samples. A lot of bibliographic databases for world research literature were structurally searched using selected review question and inclusion/exclusion criteria. Next, the reports of the highest quality were selected using standard tools (181) and they were described to evaluate the advantages and limitations of different approaches in the measurements of the steroids and their metabolites. The overview of the analytical challenges, development of methods used in the assessment of the metabolic pathways of steroid hormones, and the priorities for future research with a special consideration for liquid chromatography (LC) and capillary electrophoresis (CE) techniques have been presented. Moreover, many LC and CE applications in pharmacological and psychological studies as well as endocrinology and sports medicine, taking into account the recent progress in the area of the metabolic profiling of steroids, have been critically discussed. The latest reports show that LC systems coupled with mass spectrometry have the predominant position in the research of steroid profiles. Moreover, CE techniques are going to gain a prominent position in the diagnosis of hormone levels in the near future.

  16. The challenge of conceiving

    DEFF Research Database (Denmark)

    Hansen, Claus Thorp; Jørgensen, Ulrik

    2011-01-01

    the perspective of engineering design challenges where the need for problem identification is obvious to avoid the pitfall to reproduce and piecemeal engineer already existing product or service concepts. Problem identification is not a simple desk research task as it often involves a multitude of actors having......One of the big challenges in the CDIO approach to engineering education is the first part focusing on conceiving problems to be handled and eventually solved. Traditional engineering education has been dominated by its focus on technical disciplines emphasising their individual tool box of problem...

  17. What's to Be Done About Laboratory Quality? Process Indicators, Laboratory Stewardship, the Outcomes Problem, Risk Assessment, and Economic Value: Responding to Contemporary Global Challenges.

    Science.gov (United States)

    Meier, Frederick A; Badrick, Tony C; Sikaris, Kenneth A

    2018-02-17

    For 50 years, structure, process, and outcomes measures have assessed health care quality. For clinical laboratories, structural quality has generally been assessed by inspection. For assessing process, quality indicators (QIs), statistical monitors of steps in the clinical laboratory total testing, have proliferated across the globe. Connections between structural and process laboratory measures and patient outcomes, however, have rarely been demonstrated. To inform further development of clinical laboratory quality systems, we conducted a selective but worldwide review of publications on clinical laboratory quality assessment. Some QIs, like seven generic College of American Pathologists Q-Tracks monitors, have demonstrated significant process improvement; other measures have uncovered critical opportunities to improve test selection and result management. The College of Pathologists of Australasia Key Indicator Monitoring and Management System has deployed risk calculations, introduced from failure mode effects analysis, as surrogate measures for outcomes. Showing economic value from clinical laboratory testing quality is a challenge. Clinical laboratories should converge on fewer (7-14) rather than more (21-35) process monitors; monitors should cover all steps of the testing process under laboratory control and include especially high-risk specimen-quality QIs. Clinical laboratory stewardship, the combination of education interventions among clinician test orderers and report consumers with revision of test order formats and result reporting schemes, improves test ordering, but improving result reception is more difficult. Risk calculation reorders the importance of quality monitors by balancing three probabilities: defect frequency, weight of potential harm, and detection difficulty. The triple approach of (1) a more focused suite of generic consensus quality indicators, (2) more active clinical laboratory testing stewardship, and (3) integration of formal

  18. The Electric Car Challenge.

    Science.gov (United States)

    Diehl, Brian E.

    1997-01-01

    Describes the Electric Car Challenge during which students applied methods of construction to build lightweight, strong vehicles that were powered by electricity. The activity required problem solving, sheet metal work, electricity, design, and construction skills. (JOW)

  19. A Novel Hybridization of Applied Mathematical, Operations Research and Risk-based Methods to Achieve an Optimal Solution to a Challenging Subsurface Contamination Problem

    Science.gov (United States)

    Johnson, K. D.; Pinder, G. F.

    2013-12-01

    The objective of the project is the creation of a new, computationally based, approach to the collection, evaluation and use of data for the purpose of determining optimal strategies for investment in the solution of remediation of contaminant source areas and similar environmental problems. The research focuses on the use of existing mathematical tools assembled in a unique fashion. The area of application of this new capability is optimal (least-cost) groundwater contamination source identification; we wish to identify the physical environments wherein it may be cost-prohibitive to identify a contaminant source, the optimal strategy to protect the environment from additional insult and formulate strategies for cost-effective environmental restoration. The computational underpinnings of the proposed approach encompass the integration into a unique of several known applied-mathematical tools. The resulting tool integration achieves the following: 1) simulate groundwater flow and contaminant transport under uncertainty, that is when the physical parameters such as hydraulic conductivity are known to be described by a random field; 2) define such a random field from available field data or be able to provide insight into the sampling strategy needed to create such a field; 3) incorporate subjective information, such as the opinions of experts on the importance of factors such as locations of waste landfills; 4) optimize a search strategy for finding a potential source location and to optimally combine field information with model results to provide the best possible representation of the mean contaminant field and its geostatistics. Our approach combines in a symbiotic manner methodologies found in numerical simulation, random field analysis, Kalman filtering, fuzzy set theory and search theory. Testing the algorithm for this stage of the work, we will focus on fabricated field situations wherein we can a priori specify the degree of uncertainty associated with the

  20. Challenges in obesity research

    OpenAIRE

    Palou, Andreu; Bonet, M. Luisa

    2013-01-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors -often interrelated and many of them still unknown or poorly understood- can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regard...

  1. Virtual Bridge Design Challenge

    Science.gov (United States)

    Mitts, Charles R.

    2013-01-01

    This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

  2. Dewey's Challenge to Teachers

    Science.gov (United States)

    Fishman, Stephen M.; McCarthy, Lucille

    2010-01-01

    Given the serious social problems confronting Americans and others worldwide, the authors propose that Dewey's 1932 challenge to teachers is worthy of reconsideration by educators at all levels. In times similar to our own, Dewey challenged teachers to cultivate students' capacities to identify their happiness with what they can do to improve the…

  3. Material equations for rock salt under mechanical and thermal load including treatment of boundary value problems by the finite element method

    International Nuclear Information System (INIS)

    Olschewski, J.; Stein, E.; Wagner, W.; Wetjen, D.

    1981-01-01

    This paper is a first step in the development of thermodynamically consistent material equations for inelastic materials, such as polycrystalline rock salt. In this context it is of particular importance to reduce the number and the structure of the internal variables, in order to allow for a fit with available experimental data. As an example this is demonstrated in detail in the case of the so-called dislocation model. As physical non-linearities and in addition also geometrical non-linearities lead to an inhomogeneous deformation - and stress state even in the case of simple samples, boundary value problems have to be studied, in order to test the material equations. For this purpose the finite element method has been used. (orig./HP) [de

  4. Multi-stage thermal-economical optimization of compact heat exchangers: A new evolutionary-based design approach for real-world problems

    International Nuclear Information System (INIS)

    Yousefi, Moslem; Darus, Amer Nordin; Yousefi, Milad; Hooshyar, Danial

    2015-01-01

    The complicated task of design optimization of compact heat exchangers (CHEs) have been effectively performed by using evolutionary algorithms (EAs) in the recent years. However, mainly due to difficulties of handling extra variables, the design approach has been based on constant rates of heat duty in the available literature. In this paper, a new design strategy is presented where variable operating conditions, which better represent real-world problems, are considered. The proposed strategy is illustrated using a case study for design of a plate-fin heat exchanger though it can be employed for all types of heat exchangers without much change. Learning automata based particle swarm optimization (LAPSO), is employed for handling nine design variables while satisfying various equality and inequality constraints. For handling the constraints, a novel feasibility based ranking strategy (FBRS) is introduced. The numerical results indicate that the design based on variable heat duties yields in more cost savings and superior thermodynamics efficiency comparing to a conventional design approach. Furthermore, the proposed algorithm has shown a superior performance in finding the near-optimum solution for this task when it is compared to the most popular evolutionary algorithms in engineering applications, i.e. genetic algorithm (GA) and particle swarm optimization (PSO). - Highlights: • Multi-stage design of heat exchangers is presented. • Feasibility based ranking strategy is employed for constraint handling. • Learning abilities added to particle swarm optimization

  5. Intellectual technologies in the problems of thermal power engineering control: formalization of fuzzy information processing results using the artificial intelligence methodology

    Science.gov (United States)

    Krokhin, G.; Pestunov, A.

    2017-11-01

    Exploitation conditions of power stations in variable modes and related changes of their technical state actualized problems of creating models for decision-making and state recognition basing on diagnostics using the fuzzy logic for identification their state and managing recovering processes. There is no unified methodological approach for obtaining the relevant information is a case of fuzziness and inhomogeneity of the raw information about the equipment state. The existing methods for extracting knowledge are usually unable to provide the correspondence between of the aggregates model parameters and the actual object state. The switchover of the power engineering from the preventive repair to the one, which is implemented according to the actual technical state, increased the responsibility of those who estimate the volume and the duration of the work. It may lead to inadequacy of the diagnostics and the decision-making models if corresponding methodological preparations do not take fuzziness into account, because the nature of the state information is of this kind. In this paper, we introduce a new model which formalizes the equipment state using not only exact information, but fuzzy as well. This model is more adequate to the actual state, than traditional analogs, and may be used in order to increase the efficiency and the service period of the power installations.

  6. Cognitive Challenges

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC develop cognitive challenges (intellectual disabilities), although the degree of intellectual ...

  7. Modeling and analysis of a robust thermal control system based on forced convection thermal switches

    Science.gov (United States)

    Williams, Andrew D.; Palo, Scott E.

    2006-05-01

    There is a critical need, not just in the Department of Defense (DOD) but the entire space industry, to reduce the development time and overall cost of satellite missions. To that end, the DOD is actively pursuing the capability to reduce the deployment time of a new system from years to weeks or even days. The goal is to provide the advantages space affords not just to the strategic planner but also to the battlefield commanders. One of the most challenging aspects of this problem is the satellite's thermal control system (TCS). Traditionally the TCS must be vigorously designed, analyzed, tested, and optimized from the ground up for every satellite mission. This "reinvention of the wheel" is costly and time intensive. The next generation satellite TCS must be modular and scalable in order to cover a wide range of applications, orbits, and mission requirements. To meet these requirements a robust thermal control system utilizing forced convection thermal switches was investigated. The problem was investigated in two separate stages. The first focused on the overall design of the bus. The second stage focused on the overarching bus architecture and the design impacts of employing a thermal switch based TCS design. For the hot case, the fan provided additional cooling to increase the heat transfer rate of the subsystem. During the cold case, the result was a significant reduction in survival heater power.

  8. Idiopathic constipation: A challenging but manageable problem.

    Science.gov (United States)

    Bischoff, Andrea; Brisighelli, Giulia; Dickie, Belinda; Frischer, Jason; Levitt, Marc A; Peña, Alberto

    2017-10-10

    A protocol to treat idiopathic constipation is presented. A contrast enema is performed in every patient and, when indicated, patients are initially submitted to a "clean out" protocol. All patients are started on a Senna-based laxative. The initial dosage is empirically determined and adjusted daily, during a one week period, based on history and abdominal radiographs, until the amount of Senna that empties the colon is reached. The management is considered successful when patients empty their colon daily and stop soiling. If the laxatives dose provokes abdominal cramping, distension, and vomiting, without producing bowel movements, patients are considered nonmanageable. From 2005 to 2012, 215 patients were treated. 121 (56%) were males. The average age was 8.2years (range: 1-20). 160 patients (74%) presented encopresis. 67 patients (32%) needed a clean out. After one week, 181 patients (84%) achieved successful management, with an average Senna dose of 67mg (range: 5-175mg). In 34 patients (16%) the treatment was unsuccessful: 19 were nonmanageable, 3 noncompliant, and 12 continued soiling. At a later follow-up (median: 329days) the success rate for 174 patients was 81%. We designed a successful protocol to manage idiopathic constipation. The key points are clean out before starting laxatives, individual adjustments of laxative, and radiological monitoring of colonic emptying. Level IV. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Undergraduate Plastic Surgery Education: Problems, Challenges ...

    African Journals Online (AJOL)

    based on principles rather than limited procedures, with surgical interventions ranging from complex microsurgery-based reconstructions to aesthetic procedures. However, medical students' perceptions of the field of plastic surgery are limited and underestimate the versatility of services offered by plastic surgeons.[1,2] In ...

  10. Posting of workers : Enforcement problems and challenges

    NARCIS (Netherlands)

    Cremers, Jan

    2013-01-01

    Expert contribution to a final conference. According to the author, monitoring the process of posting and controlling the regular character of the cross-border provision of services with posted workers has proven to be a problematic area. Recent joint activities of the labour inspectorate have

  11. Vulvodynia – still a challenging therapeutic problem

    Directory of Open Access Journals (Sweden)

    Magdalena Pawlaczyk

    2017-04-01

    Full Text Available Introduction . Vulvodynia is a chronic condition characterized by pain and burning in the vulvar area without any abnormalities in clinical and laboratory examinations. The diagnosis is based on detailed assessment of medical history, physical examination and exclusion of other potential causes of vulvar pain. As yet, no definitive treatment algorithm has been universally accepted for vulvodynia. Objective . To present a case of successful treatment of generalized spontaneous vulvodynia with low doses of amitriptyline. Case report . A 42-year-old patient presented to a dermatology outpatient clinic with chronic generalized vulvar pain of 2 years’ duration. She was diagnosed with generalized spontaneous vulvodynia. Amitriptyline treatment was introduced and supported by topical application of lignocaine gel. After 13 months of amitriptyline therapy a complete remission was achieved. Conclusions . Vulvodynia is a complex disease with numerous presentations, the symptoms of which often overlap. Since the diagnosis of vulvodynia requires the exclusion of other abnormalities, it is fundamental to raise the awareness of the disease among clinicians, so as to enable early correct diagnosis and adequate treatment.

  12. Physics of rotation: problems and challenges

    Science.gov (United States)

    Maeder, Andre; Meynet, Georges

    2015-01-01

    We examine some debated points in current discussions about rotating stars: the shape, the gravity darkening, the critical velocities, the mass loss rates, the hydrodynamical instabilities, the internal mixing and N-enrichments. The study of rotational mixing requires high quality data and careful analysis. From recent studies where such conditions are fulfilled, rotational mixing is well confirmed. Magnetic coupling with stellar winds may produce an apparent contradiction, i.e. stars with a low rotation and a high N-enrichment. We point out that it rather confirms the large role of shears in differentially rotating stars for the transport processes. New models of interacting binaries also show how shears and mixing may be enhanced in close binaries which are either spun up or down by tidal interactions.

  13. Thermal stability and thermal conductivity of phosphorene in phosphorene/graphene van der Waals heterostructures.

    Science.gov (United States)

    Pei, Qing-Xiang; Zhang, Xiaoliang; Ding, Zhiwei; Zhang, Ying-Yan; Zhang, Yong-Wei

    2017-07-14

    Phosphorene, a new two-dimensional (2D) semiconducting material, has attracted tremendous attention recently. However, its structural instability under ambient conditions poses a great challenge to its practical applications. A possible solution for this problem is to encapsulate phosphorene with more stable 2D materials, such as graphene, forming van der Waals heterostructures. In this study, using molecular dynamics simulations, we show that the thermal stability of phosphorene in phosphorene/graphene heterostructures can be enhanced significantly. By sandwiching phosphorene between two graphene sheets, its thermally stable temperature is increased by 150 K. We further study the thermal transport properties of phosphorene and find surprisingly that the in-plane thermal conductivity of phosphorene in phosphorene/graphene heterostructures is much higher than that of the free-standing one, with a net increase of 20-60%. This surprising increase in thermal conductivity arises from the increase in phonon group velocity and the extremely strong phonon coupling between phosphorene and the graphene substrate. Our findings have an important meaning for the practical applications of phosphorene in nanodevices.

  14. Numerically modeling Brownian thermal noise in amorphous and crystalline thin coatings

    Science.gov (United States)

    Lovelace, Geoffrey; Demos, Nicholas; Khan, Haroon

    2018-01-01

    Thermal noise is expected to be one of the noise sources limiting the astrophysical reach of Advanced LIGO (once commissioning is complete) and third-generation detectors. Adopting crystalline materials for thin, reflecting mirror coatings, rather than the amorphous coatings used in current-generation detectors, could potentially reduce thermal noise. Understanding and reducing thermal noise requires accurate theoretical models, but modeling thermal noise analytically is especially challenging with crystalline materials. Thermal noise models typically rely on the fluctuation-dissipation theorem, which relates the power spectral density of the thermal noise to an auxiliary elastic problem. In this paper, we present results from a new, open-source tool that numerically solves the auxiliary elastic problem to compute the Brownian thermal noise for both amorphous and crystalline coatings. We employ the open-source deal.ii and PETSc frameworks to solve the auxiliary elastic problem using a finite-element method, adaptive mesh refinement, and parallel processing that enables us to use high resolutions capable of resolving the thin reflective coating. We verify numerical convergence, and by running on up to hundreds of compute cores, we resolve the coating elastic energy in the auxiliary problem to approximately 0.1%. We compare with approximate analytic solutions for amorphous materials, and we verify that our solutions scale as expected with changing beam size, mirror dimensions, and coating thickness. Finally, we model the crystalline coating thermal noise in an experiment reported by Cole et al (2013 Nat. Photon. 7 644–50), comparing our results to a simpler numerical calculation that treats the coating as an ‘effectively amorphous’ material. We find that treating the coating as a cubic crystal instead of as an effectively amorphous material increases the thermal noise by about 3%. Our results are a step toward better understanding and reducing thermal noise to

  15. Mathematical olympiad challenges

    CERN Document Server

    Andreescu, Titu

    2000-01-01

    Mathematical Olympiad Challenges is a rich collection of problems put together by two experienced and well-known professors and coaches of the U.S. International Mathematical Olympiad Team. Hundreds of beautiful, challenging, and instructive problems from algebra, geometry, trigonometry, combinatorics, and number theory were selected from numerous mathematical competitions and journals. An important feature of the work is the comprehensive background material provided with each grouping of problems. The problems are clustered by topic into self-contained sections with solutions provided separately. All sections start with an essay discussing basic facts and one or two representative examples. A list of carefully chosen problems follows and the reader is invited to take them on. Additionally, historical insights and asides are presented to stimulate further inquiry. The emphasis throughout is on encouraging readers to move away from routine exercises and memorized algorithms toward creative solutions to open-e...

  16. Benchmark Problems of the Geothermal Technologies Office Code Comparison Study

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Podgorney, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelkar, Sharad M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McClure, Mark W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Danko, George [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ghassemi, Ahmad [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fu, Pengcheng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bahrami, Davood [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barbier, Charlotte [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cheng, Qinglu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chiu, Kit-Kwan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Detournay, Christine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elsworth, Derek [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fang, Yi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Furtney, Jason K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gan, Quan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gao, Qian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Guo, Bin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hao, Yue [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horne, Roland N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Kai [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Im, Kyungjae [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Norbeck, Jack [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rutqvist, Jonny [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Safari, M. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sesetty, Varahanaresh [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sonnenthal, Eric [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tao, Qingfeng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); White, Signe K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wong, Yang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xia, Yidong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-12-02

    A diverse suite of numerical simulators is currently being applied to predict or understand the performance of enhanced geothermal systems (EGS). To build confidence and identify critical development needs for these analytical tools, the United States Department of Energy, Geothermal Technologies Office has sponsored a Code Comparison Study (GTO-CCS), with participants from universities, industry, and national laboratories. A principal objective for the study was to create a community forum for improvement and verification of numerical simulators for EGS modeling. Teams participating in the study were those representing U.S. national laboratories, universities, and industries, and each team brought unique numerical simulation capabilities to bear on the problems. Two classes of problems were developed during the study, benchmark problems and challenge problems. The benchmark problems were structured to test the ability of the collection of numerical simulators to solve various combinations of coupled thermal, hydrologic, geomechanical, and geochemical processes. This class of problems was strictly defined in terms of properties, driving forces, initial conditions, and boundary conditions. Study participants submitted solutions to problems for which their simulation tools were deemed capable or nearly capable. Some participating codes were originally developed for EGS applications whereas some others were designed for different applications but can simulate processes similar to those in EGS. Solution submissions from both were encouraged. In some cases, participants made small incremental changes to their numerical simulation codes to address specific elements of the problem, and in other cases participants submitted solutions with existing simulation tools, acknowledging the limitations of the code. The challenge problems were based on the enhanced geothermal systems research conducted at Fenton Hill, near Los Alamos, New Mexico, between 1974 and 1995. The problems

  17. Thermal Dissipation Efficiency in a Micro-Processor Using Carbon Nanotubes Based Composite

    Science.gov (United States)

    Thang, Bui Hung; Van Quang, Cao; Nghia, Van Trong; Hong, Phan Ngoc; Van Chuc, Nguyen; Tam, Ngo Thi Thanh; Quang, Le Dinh; Khang, Dao Duc; Khoi, Phan Hong; Minh, Phan Ngoc

    2009-09-01

    Modern electronic and optoelectronic devices such as μ-processor, light emitting diode, semiconductor laser issued a challenge in the thermal dissipation problem. Finding an effective way for thermal dissipation therefore becomes a very important issue. It is known that carbon nanotubes (CNTs) is one of the most valuable materials with high thermal conductivity (2000 W/m.K compared to thermal conductivity of Ag 419 W/m.K). This suggested an approach in applying the CNTs as an essential component for thermal dissipation media to improve the performance of computer processor and other high power electronic devices. In this work multi walled carbon nanotubes (MWCNTs) based composites were utilized as the thermal dissipation media in a micro processor of a personal computer. The MWCNTs of different concentrations were added into polyaniline, commercial silicon thermal paste and commercial silver thermal paste by mechanical methods. A personal computer with configuration: Intel Pentium IV 3.066 GHz, 512 MB of RAM and Windows XP Service Pack 2 Operating System was employed. The thermal dissipation efficiency of the system was evaluated by directly measure the temperature of the μ-processor during the operation of the computer in different CPU speeds. The measured results showed that the CNTs based composite could reduce the temperature of the u-processor more than 5° C, and the time for increasing the temperature of the μ-processor was three times longer than that when using commercial thermal paste.

  18. Thermal comfort

    CSIR Research Space (South Africa)

    Osburn, L

    2010-01-01

    Full Text Available Thermal comfort is influenced by environmental parameters as well as other influences including asymmetric heating and cooling conditions. Additionally, some aspects of thermal comfort may be exploited so as to enable a building to operate within a...

  19. Word Problem Wizardry.

    Science.gov (United States)

    Cassidy, Jack

    1991-01-01

    Presents suggestions for teaching math word problems to elementary students. The strategies take into consideration differences between reading in math and reading in other areas. A problem-prediction game and four self-checking activities are included along with a magic password challenge. (SM)

  20. Problems in quantum mechanics

    CERN Document Server

    Goldman, Iosif Ilich; Geilikman, B T

    2006-01-01

    This challenging book contains a comprehensive collection of problems in nonrelativistic quantum mechanics of varying degrees of difficulty. It features answers and completely worked-out solutions to each problem. Geared toward advanced undergraduates and graduate students, it provides an ideal adjunct to any textbook in quantum mechanics.

  1. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ... myths Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ...

  2. Overcoming challenges

    Medline Plus

    Full Text Available ... section Back to section menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work ... It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths Overcoming challenges Common questions ...

  3. Thermal Management and Thermal Protection Systems

    Science.gov (United States)

    Hasnain, Aqib

    2016-01-01

    During my internship in the Thermal Design Branch (ES3), I contributed to two main projects: i) novel passive thermal management system for future human exploration, ii) AVCOAT undercut thermal analysis. i) As NASA prepares to further expand human and robotic presence in space, it is well known that spacecraft architectures will be challenged with unprecedented thermal environments. Future exploration activities will have the need of thermal management systems that can provide higher reliability, mass and power reduction and increased performance. In an effort to start addressing the current technical gaps the NASA Johnson Space Center Passive Thermal Discipline has engaged in technology development activities. One of these activities was done through an in-house Passive Thermal Management System (PTMS) design for a lunar lander. The proposed PTMS, functional in both microgravity and gravity environments, consists of three main components: a heat spreader, a novel hybrid wick Variable Conductance Heat Pipe (VCHP), and a radiator. The aim of this PTMS is to keep electronics on a vehicle within their temperature limits (0 and 50 C for the current design) during all mission phases including multiple lunar day/night cycles. The VCHP was tested to verify its thermal performance. I created a thermal math model using Thermal Desktop (TD) and analyzed it to predict the PTMS performance. After testing, the test data provided a means to correlate the thermal math model. This correlation took into account conduction and convection heat transfer, representing the actual benchtop test. Since this PTMS is proposed for space missions, a vacuum test will be taking place to provide confidence that the system is functional in space environments. Therefore, the model was modified to include a vacuum chamber with a liquid nitrogen shroud while taking into account conduction and radiation heat transfer. Infrared Lamps were modelled and introduced into the model to simulate the sun

  4. Exploration of porous SiC nanostructures as thermal insulator with high thermal stability and low thermal conductivity

    Institute of Scientific and Technical Information of China (English)

    Peng; WAN; Jingyang; WANG

    2016-01-01

    The crucial challenge for current nanoscale thermal insulation materials,such as Al2O3 and SiO2 aerogel composites,is to solve the trade-off between extremely low thermal conductivity and unsatisfied thermal stability.Typical high-temperature ceramic SiC possesses excellent mechanical properties and

  5. Aquifer Thermal Energy Storage for Seasonal Thermal Energy Balance

    Science.gov (United States)

    Rostampour, Vahab; Bloemendal, Martin; Keviczky, Tamas

    2017-04-01

    Aquifer Thermal Energy Storage (ATES) systems allow storing large quantities of thermal energy in subsurface aquifers enabling significant energy savings and greenhouse gas reductions. This is achieved by injection and extraction of water into and from saturated underground aquifers, simultaneously. An ATES system consists of two wells and operates in a seasonal mode. One well is used for the storage of cold water, the other one for the storage of heat. In warm seasons, cold water is extracted from the cold well to provide cooling to a building. The temperature of the extracted cold water increases as it passes through the building climate control systems and then gets simultaneously, injected back into the warm well. This procedure is reversed during cold seasons where the flow direction is reversed such that the warmer water is extracted from the warm well to provide heating to a building. From the perspective of building climate comfort systems, an ATES system is considered as a seasonal storage system that can be a heat source or sink, or as a storage for thermal energy. This leads to an interesting and challenging optimal control problem of the building climate comfort system that can be used to develop a seasonal-based energy management strategy. In [1] we develop a control-oriented model to predict thermal energy balance in a building climate control system integrated with ATES. Such a model however cannot cope with off-nominal but realistic situations such as when the wells are completely depleted, or the start-up phase of newly installed wells, etc., leading to direct usage of aquifer ambient temperature. Building upon our previous work in [1], we here extend the mathematical model for ATES system to handle the above mentioned more realistic situations. Using our improved models, one can more precisely predict system behavior and apply optimal control strategies to manage the building climate comfort along with energy savings and greenhouse gas reductions

  6. Review of prediction for thermal contact resistance

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Theoretical prediction research on thermal contact resistance is reviewed in this paper. In general, modeling or simulating the thermal contact resistance involves several aspects, including the descriptions of surface topography, the analysis of micro mechanical deformation, and the thermal models. Some key problems are proposed for accurately predicting the thermal resistance of two solid contact surfaces. We provide a perspective on further promising research, which would be beneficial to understanding mechanisms and engineering applications of the thermal contact resistance in heat transport phenomena.

  7. Balance Problems

    Science.gov (United States)

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady. You may ... related injuries, such as a hip fracture. Some balance problems are due to problems in the inner ...

  8. Thermal reactor strategy

    International Nuclear Information System (INIS)

    1981-01-01

    This statement sets down briefly the CEGB's views on the requirement for nuclear power and outlines current progress in the implementation of the CEGB's thermal reactor strategy. The programme is traced historically, together with statements of Government policy. The place of Magnox, AGR, SGHWR, PWR and fast breeder reactors is discussed. Advantages and problems associated with the various types are outlined. (U.K.)

  9. Thermal Cameras and Applications

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

    Thermal cameras are passive sensors that capture the infrared radiation emitted by all objects with a temperature above absolute zero. This type of camera was originally developed as a surveillance and night vision tool for the military, but recently the price has dropped, significantly opening up...... a broader field of applications. Deploying this type of sensor in vision systems eliminates the illumination problems of normal greyscale and RGB cameras. This survey provides an overview of the current applications of thermal cameras. Applications include animals, agriculture, buildings, gas detection......, industrial, and military applications, as well as detection, tracking, and recognition of humans. Moreover, this survey describes the nature of thermal radiation and the technology of thermal cameras....

  10. Challenges of serious games

    Directory of Open Access Journals (Sweden)

    B. Fernández-Manjón

    2015-11-01

    Full Text Available Although educational games have revealed to be a very effective focus in diverse situations, their use in education is still very limited. In this paper we analyse the main challenges concerning educational games that, from our perspective, have to be approached so that the use of this kind of games can be widespread. These challenges are classified in three main dimensions: socio-cultural, educational and technological. Once the challenges are identified, some possible measures are suggested to address or reduce these problems so that the use of educational games may be widespread.

  11. 河西走廊流域治理的科学问题及其思考%The key problems and challenges on the river basin governance in the Hexi Corridor, Gansu, China

    Institute of Scientific and Technical Information of China (English)

    王忠静; 郑航; 耿国婷

    2011-01-01

    针对河西走廊三流域治理,从水资源承载能力、社会经济发展模式、水资源利用秩序等方面,剖析各流域产生生态问题的科学必然性,以及流域治理手段的针对性.从黑河、石羊河流域治理的效果及流域演化基本规律出发,提出河西走廊三流域后治理时代可持续发展在气候变化、经济转型和粮食安全等方面的科学思考.%The inevitability of the occurrence of ecological issues and targets of the governance of the Three River Basins in the Hexi Corridor (the Corridor West of the Yellow River) were analyzed in terms of water resources carrying capacity, socio-economic development patterns and the order of water resources use. Based on both the effects of governing the Heihe River and the Shiyang River Basin and on the basic rules of river evolution, the key problems and challenges on the sustainable development during the post-management period of the Three River Basins in the Hexi Corridor were proposed in terms of climate change, economic transition and food safety.

  12. [Population problem, comprehension problem].

    Science.gov (United States)

    Tallon, F

    1993-08-01

    Overpopulation of developing countries in general, and Rwanda in particular, is not just their problem but a problem for developed countries as well. Rapid population growth is a key factor in the increase of poverty in sub-Saharan Africa. Population growth outstrips food production. Africa receives more and more foreign food, economic, and family planning aid each year. The Government of Rwanda encourages reduced population growth. Some people criticize it, but this criticism results in mortality and suffering. One must combat this ignorance, but attitudes change slowly. Some of these same people find the government's acceptance of family planning an invasion of their privacy. Others complain that rich countries do not have campaigns to reduce births, so why should Rwanda do so? The rate of schooling does not increase in Africa, even though the number of children in school increases, because of rapid population growth. Education is key to improvements in Africa's socioeconomic growth. Thus, Africa, is underpopulated in terms of potentiality but overpopulated in terms of reality, current conditions, and possibilities of overexploitation. Africa needs to invest in human resources. Families need to save, and to so, they must refrain from having many children. Africa should resist the temptation to waste, as rich countries do, and denounce it. Africa needs to become more independent of these countries, but structural adjustment plans, growing debt, and rapid population growth limit national independence. Food aid is a means for developed countries to dominate developing countries. Modernization through foreign aid has had some positive effects on developing countries (e.g., improved hygiene, mortality reduction), but these also sparked rapid population growth. Rwandan society is no longer traditional, but it is also not yet modern. A change in mentality to fewer births, better quality of life for living infants, better education, and less burden for women must occur

  13. Controlling Thermal Expansion: A Metal–Organic Frameworks Route

    Science.gov (United States)

    2016-01-01

    Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal–organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model material, along with three molecules of similar size and known differences in terms of the nature of host–guest interactions. It has been shown that adsorbate molecules can control, in a colligative way, the thermal expansion of the solid, so that changing the adsorbate molecules induces the solid to display positive, zero, or negative thermal expansion. We analyze in depth the distortion mechanisms, beyond the ligand metal junction, to cover the ligand distortions, and the energetic and entropic effect on the thermo-structural behavior. We provide an unprecedented atomistic insight on the effect of adsorbates on the thermal expansion of MOFs as a basic tool toward controlling the thermal expansion. PMID:28190918

  14. Controlling Thermal Expansion: A Metal-Organic Frameworks Route.

    Science.gov (United States)

    Balestra, Salvador R G; Bueno-Perez, Rocio; Hamad, Said; Dubbeldam, David; Ruiz-Salvador, A Rabdel; Calero, Sofia

    2016-11-22

    Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal-organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model material, along with three molecules of similar size and known differences in terms of the nature of host-guest interactions. It has been shown that adsorbate molecules can control, in a colligative way, the thermal expansion of the solid, so that changing the adsorbate molecules induces the solid to display positive, zero, or negative thermal expansion. We analyze in depth the distortion mechanisms, beyond the ligand metal junction, to cover the ligand distortions, and the energetic and entropic effect on the thermo-structural behavior. We provide an unprecedented atomistic insight on the effect of adsorbates on the thermal expansion of MOFs as a basic tool toward controlling the thermal expansion.

  15. Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

    OpenAIRE

    Fei-Ran Shen; Hao Kuang; Feng-Xia Hu; Hui Wu; Qing-Zhen Huang; Fei-Xiang Liang; Kai-Ming Qiao; Jia Li; Jing Wang; Yao Liu; Lei Zhang; Min He; Ying Zhang; Wen-Liang Zuo; Ji-Rong Sun

    2017-01-01

    Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn–Co–Ge–In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE o...

  16. Regulatory challenges

    International Nuclear Information System (INIS)

    Austvik, Ole Gunnar

    2003-01-01

    The problem for policy makers wanting to liberalize natural gas markets is that its concentrated structure may also be the socially most efficient one. Because of scale economies, more firms operating in the market may incur higher transportation costs unless the market grows sufficiently in each geographic segment. This argument goes for product extension through vertical (or horizontal) integration and the exploitation of economies of scope as well. Thus, the challenge for governments is to intervene in a way that preserves a market structure that has the potential to minimize cost, and at the same lime change its behavior in order to avoid possible lax cost control and exploitation of market power. The existence of scope advantages indicates that liberalization of the market should open for the possibility to bundle services in competition with provision of unbundled services. If operations are unbundled and there exist economies of scope, the gain from increased competition should be weighed against the losses of less efficient operations of each firm. Thus, with the growth in the European market, gradually more arguments support the idea of unbundling. The significant scale economy in trunk pipelines, sunk investments and capital immobility, possible economies of scope in vertical integration and companies' bundling of services influences vertical and horizontal ownership relations and contractual terms in the European gas market. In specific segments of the markets, these relationships may promote efficient investments and pricing without public interference, but the strong concentration of market power indicates that this is rather the exception than the rule. In order to design an efficient and welfare maximizing way of regulating the market one needs a closer identification of the actual goal of the regulation. Microeconomic theory is often used for this purpose. The author discusses the alternatives of laissez-faire, nationalization or regulation for the

  17. Experimental Preparation and Numerical Simulation of High Thermal Conductive Cu/CNTs Nanocomposites

    Directory of Open Access Journals (Sweden)

    Muhsan Ali Samer

    2014-07-01

    Full Text Available Due to the rapid growth of high performance electronics devices accompanied by overheating problem, heat dissipater nanocomposites material having ultra-high thermal conductivity and low coefficient of thermal expansion was proposed. In this work, a nanocomposite material made of copper (Cu reinforced by multi-walled carbon nanotubes (CNTs up to 10 vol. % was prepared and their thermal behaviour was measured experimentally and evaluated using numerical simulation. In order to numerically predict the thermal behaviour of Cu/CNTs composites, three different prediction methods were performed. The results showed that rules of mixture method records the highest thermal conductivity for all predicted composites. In contrast, the prediction model which takes into account the influence of the interface thermal resistance between CNTs and copper particles, has shown the lowest thermal conductivity which considered as the closest results to the experimental measurement. The experimentally measured thermal conductivities showed remarkable increase after adding 5 vol.% CNTs and higher than the thermal conductivities predicted via Nan models, indicating that the improved fabrication technique of powder injection molding that has been used to produced Cu/CNTs nanocomposites has overcome the challenges assumed in the mathematical models.

  18. Early breastfeeding problems

    DEFF Research Database (Denmark)

    Feenstra, Maria Monberg; Kirkeby, Mette Jørgine; Thygesen, Marianne

    2018-01-01

    Objectives Breastfeeding problems are common and associated with early cessation. Stilllength of postpartum hospital stay has been reduced. This leaves new mothers to establish breastfeeding at home with less support from health care professionals. The objective was to explore mothers’ perspectives...... on when breastfeeding problems were the most challenging and prominent early postnatal. The aim was also toidentify possible factors associated with the breastfeeding problems. Methods In a cross-sectional study, a mixed method approach was used to analyse postal survey data from 1437 mothers with full...... term singleton infants. Content analysis was used to analyse mothers’ open text descriptions of their most challenging breastfeeding problem. Multiple logistic regression was used to calculate odds ratios for early breastfeeding problems according to sociodemographic- and psychosocial factors. Results...

  19. Problems in equilibrium theory

    CERN Document Server

    Aliprantis, Charalambos D

    1996-01-01

    In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.

  20. Thermal insulation

    International Nuclear Information System (INIS)

    Aspden, G.J.; Howard, R.S.

    1988-01-01

    The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

  1. Nanoscale thermal transport

    Science.gov (United States)

    Cahill, David G.; Ford, Wayne K.; Goodson, Kenneth E.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Merlin, Roberto; Phillpot, Simon R.

    2003-01-01

    Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid-solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The

  2. Energy mastery, 30 years later. New challenges in the sustainable development context

    International Nuclear Information System (INIS)

    Padet, J.; Bissieux, C.; Padet, C.; Lachi, M.; Pron, H.

    2005-01-01

    The main topic of the 2005 issue of the annual congress of the French society of thermal engineering (SFT) is the energy mastery as a response to the sustainable development challenge. These proceedings gather 130 publications shared between 5 sessions dealing with: transfers in multiphase environments (two-phase and phase change); convective transfers (natural, mixed, forced and jets); coupled transfers (radiant, combustion, plasmas, porous media, drying); thermophysical properties (micro-thermal, interfaces, measurements, identification); thermal systems (exchangers, processes, energetics). Among these, two articles are relevant for the INIS database, one treats of the thermal problems encountered with thermonuclear fusion. and the other deals with the scientific policy of the French agency of environment and energy mastery (Ademe). (J.S.)

  3. Efficient thermal management for multiprocessor systems

    OpenAIRE

    Coşkun, Ayşe Kıvılcım

    2009-01-01

    High temperatures and large thermal variations on the die create severe challenges in system reliability, performance, leakage power, and cooling costs. Designing for worst-case thermal conditions is highly costly and time-consuming. Therefore, dynamic thermal management methods are needed to maintain safe temperature levels during execution. Conventional management techniques sacrifice performance to control temperature and only consider the hot spots, neglecting the effects of thermal varia...

  4. Future nuclear regulatory challenges

    International Nuclear Information System (INIS)

    Royen, J.

    1998-01-01

    In December 1996, the NEA Committee on Nuclear Regulatory Activities concluded that changes resulting from economic deregulation and other recent developments affecting nuclear power programmes have consequences both for licensees and regulatory authorities. A number of potential problems and issues which will present a challenge to nuclear regulatory bodies over the next ten years have been identified in a report just released. (author)

  5. Centennial Challenges Program

    Science.gov (United States)

    Ortega, Sam; Eberly, Eric

    2015-01-01

    NASA's Centennial Challenges Program was initiated in 2005 to directly engage the public in the process of advanced technology development. The program offers incentive prizes to generate revolutionary solutions to problems of interest to NASA and the nation. The program seeks innovations from diverse and nontraditional sources. Competitors are not supported by government funding and awards are only made to successful teams when the challenges are met. In keeping with the spirit of the Wright Brothers and other American innovators, the Centennial Challenge prizes are offered to independent inventors including small businesses, student groups, and individuals. These independent inventors are sought to generate innovative solutions for technical problems of interest to NASA and the nation and to provide them with the opportunity to stimulate or create new business ventures.

  6. Thermal insulation

    International Nuclear Information System (INIS)

    Pinsky, G.P.

    1977-01-01

    Thermal insulation for vessels and piping within the reactor containment area of nuclear power plants is disclosed. The thermal insulation of this invention can be readily removed and replaced from the vessels and piping for inservice inspection, can withstand repeated wettings and dryings, and can resist high temperatures for long periods of time. 4 claims, 3 figures

  7. De los problemas a los retos de la población rural de Castilla y León. (From the problems to the challenges of the rural population in Castile-Leon.

    Directory of Open Access Journals (Sweden)

    José Manuel del Barrio Aliste

    2013-12-01

    Full Text Available Uno de los temas que más preocupan en la actualidad en Castilla y León es el relacionado con los problemas y desafíos de la población en las zonas rurales. Con el fin de contribuir al debate sobre esta cuestión, este texto pretende ofrecer algunas reflexiones sobre este importante y controvertido tema. En primer lugar, se reflexiona sobre la importancia de las cuestiones de población en el imaginario colectivo de la región, en el estado de la autonomía y en la “Agenda para la Población de Castilla y León”. En segundo lugar, se aportan algunos datos poblacionales básicos, poniendo de relieve las disparidades, las diferencias demográficas y los contrastes que existen en la región. Por último, en tercer lugar, proporcionar algunas propuestas para la acción, centrándose en particular en las implicaciones de los nuevos escenarios de la ruralidad. One of the issues that most concern in Castile-Leon are related to the problems and challenges of the population in rural areas. In order to contribute to the debate on this question, this text seeks to provide some thoughts about this important and controversial issue. First, some reflections about the importance of population issues in the collective imagination of the region, in the status of autonomy and in the “Agenda for the Population of Castile-Leon”. Secondly, there is some basic population data, highlighting the disparities, demographic differences and contrasts that exist in the region. Finally, thirdly, some proposals for action are provided, focusing in particular on the implications of the new context in the rural areas.

  8. Speech Problems

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Speech Problems KidsHealth / For Teens / Speech Problems What's in ... a person's ability to speak clearly. Some Common Speech and Language Disorders Stuttering is a problem that ...

  9. Thermal management of batteries

    Science.gov (United States)

    Gibbard, H. F.; Chen, C.-C.

    Control of the internal temperature during high rate discharge or charge can be a major design problem for large, high energy density battery systems. A systematic approach to the thermal management of such systems is described for different load profiles based on: thermodynamic calculations of internal heat generation; calorimetric measurements of heat flux; analytical and finite difference calculations of the internal temperature distribution; appropriate system designs for heat removal and temperature control. Examples are presented of thermal studies on large lead-acid batteries for electrical utility load levelling and nickel-zinc and lithium-iron sulphide batteries for electric vehicle propulsion.

  10. Hemiequilibrium problems

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Noor

    2004-01-01

    Full Text Available We consider a new class of equilibrium problems, known as hemiequilibrium problems. Using the auxiliary principle technique, we suggest and analyze a class of iterative algorithms for solving hemiequilibrium problems, the convergence of which requires either pseudomonotonicity or partially relaxed strong monotonicity. As a special case, we obtain a new method for hemivariational inequalities. Since hemiequilibrium problems include hemivariational inequalities and equilibrium problems as special cases, the results proved in this paper still hold for these problems.

  11. Modelling of thermal conductance during microthermal machining with scanning thermal microscope using an inverse methodology

    International Nuclear Information System (INIS)

    Yang Yuching; Chang Winjin; Fang Tehua; Fang Shihchung

    2008-01-01

    In this study, a general methodology for determining the thermal conductance between the probe tip and the workpiece during microthermal machining using Scanning Thermal Microscopy (SThM) has been proposed. The processing system was considered as an inverse heat conduction problem with an unknown thermal conductance. Temperature dependence for the material properties and thermal conductance in the analysis of heat conduction is taken into account. The conjugate gradient method is used to solve the inverse problem. Furthermore, this methodology can also be applied to estimate the thermal contact conductance in other transient heat conduction problems, like metal casting process, injection molding process, and electronic circuit systems

  12. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne, CH and P. BRUZZONE / CRPP-EPFL, Zürich, CH The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the...

  13. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne and P. BRUZZONE / CRPP-EPFL, Zürich The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the de...

  14. Stochastic modelling of thermal fatigue crack growth for applying in the structural reliability of nuclear piping

    International Nuclear Information System (INIS)

    Radu, V.

    2016-01-01

    The problem of thermal fatigue in mixing areas arises in nuclear piping where a turbulent mixing or vortices produce rapid fluid temperature fluctuations with random frequencies. The assessment of fatigue crack growth due to cyclic thermal loads arising from turbulent mixing presents significant challenges, principally due to the difficulty of establishing the actual loading spectrum. To apply the Stochastic approach of thermal fatigue, a frequency temperature response function is proposed. For the elastic thermal stresses distribution solutions, the magnitude of the frequency response function is first derived and checked against the prediction by FEA. The connection between SIF.s power spectral density (PSD) and temperature.s PSD is assured with SIF frequency response function modulus. The frequency of the peaks of each magnitude for KI is supposed to be a stationary narrow-band Gaussian process. The probabilities of failure are estimated by means of the Monte Carlo methods considering a limit state function. (authors)

  15. Origin of coronal mass ejection and magnetic cloud: Thermal or magnetic driven?

    Science.gov (United States)

    Zhang, Gong-Liang; Wang, Chi; He, Shuang-Hua

    1995-01-01

    A fundamental problem in Solar-Terrestrial Physics is the origin of the solar transient plasma output, which includes the coronal mass ejection and its interplanetary manifestation, e.g. the magnetic cloud. The traditional blast wave model resulted from solar thermal pressure impulse has faced with challenge during recent years. In the MHD numerical simulation study of CME, the authors find that the basic feature of the asymmetrical event on 18 August 1980 can be reproduced neither by a thermal pressure nor by a speed increment. Also, the thermal pressure model fails in simulating the interplanetary structure with low thermal pressure and strong magnetic field strength, representative of a typical magnetic cloud. Instead, the numerical simulation results are in favor of the magnetic field expansion as the likely mechanism for both the asymmetrical CME event and magnetic cloud.

  16. Optimal control in thermal engineering

    CERN Document Server

    Badescu, Viorel

    2017-01-01

    This book is the first major work covering applications in thermal engineering and offering a comprehensive introduction to optimal control theory, which has applications in mechanical engineering, particularly aircraft and missile trajectory optimization. The book is organized in three parts: The first part includes a brief presentation of function optimization and variational calculus, while the second part presents a summary of the optimal control theory. Lastly, the third part describes several applications of optimal control theory in solving various thermal engineering problems. These applications are grouped in four sections: heat transfer and thermal energy storage, solar thermal engineering, heat engines and lubrication.Clearly presented and easy-to-use, it is a valuable resource for thermal engineers and thermal-system designers as well as postgraduate students.

  17. Overcoming challenges

    Medline Plus

    Full Text Available ... Disease and Stroke HIV and AIDS Mental Health Pain Pregnancy Reproductive Health Sexual Health Sexually Transmitted Infections ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch ...

  18. Overcoming challenges

    Medline Plus

    Full Text Available ... menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work for you Addressing breastfeeding ... in the African-American community Incredible facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about ...

  19. Overcoming challenges

    Medline Plus

    Full Text Available ... facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding support It takes a village: Building ...

  20. Cognitive Challenges

    Science.gov (United States)

    ... Alliance Our Story Our Vision Our Team Our Leadership Our Results Our Corporate Policies FAQs Careers Contact Us Media Store Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC ...

  1. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit Overcoming challenges Breastfeeding has a long list ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit All material contained on ...

  2. Overcoming challenges

    Medline Plus

    Full Text Available ... into your life Breastfeeding in daily life: At home and in public Laws that support breastfeeding 10 ... and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  3. Thermal modelling using discrete vasculature for thermal therapy: a review

    Science.gov (United States)

    Kok, H.P.; Gellermann, J.; van den Berg, C.A.T.; Stauffer, P.R.; Hand, J.W.; Crezee, J.

    2013-01-01

    Reliable temperature information during clinical hyperthermia and thermal ablation is essential for adequate treatment control, but conventional temperature measurements do not provide 3D temperature information. Treatment planning is a very useful tool to improve treatment quality and substantial progress has been made over the last decade. Thermal modelling is a very important and challenging aspect of hyperthermia treatment planning. Various thermal models have been developed for this purpose, with varying complexity. Since blood perfusion is such an important factor in thermal redistribution of energy in in vivo tissue, thermal simulations are most accurately performed by modelling discrete vasculature. This review describes the progress in thermal modelling with discrete vasculature for the purpose of hyperthermia treatment planning and thermal ablation. There has been significant progress in thermal modelling with discrete vasculature. Recent developments have made real-time simulations possible, which can provide feedback during treatment for improved therapy. Future clinical application of thermal modelling with discrete vasculature in hyperthermia treatment planning is expected to further improve treatment quality. PMID:23738700

  4. Local quantum thermal susceptibility

    Science.gov (United States)

    de Pasquale, Antonella; Rossini, Davide; Fazio, Rosario; Giovannetti, Vittorio

    2016-09-01

    Thermodynamics relies on the possibility to describe systems composed of a large number of constituents in terms of few macroscopic variables. Its foundations are rooted into the paradigm of statistical mechanics, where thermal properties originate from averaging procedures which smoothen out local details. While undoubtedly successful, elegant and formally correct, this approach carries over an operational problem, namely determining the precision at which such variables are inferred, when technical/practical limitations restrict our capabilities to local probing. Here we introduce the local quantum thermal susceptibility, a quantifier for the best achievable accuracy for temperature estimation via local measurements. Our method relies on basic concepts of quantum estimation theory, providing an operative strategy to address the local thermal response of arbitrary quantum systems at equilibrium. At low temperatures, it highlights the local distinguishability of the ground state from the excited sub-manifolds, thus providing a method to locate quantum phase transitions.

  5. Thermal stress and seismogenesis

    International Nuclear Information System (INIS)

    Zhou Huilan; Wei Dongping

    1989-05-01

    In this paper, the Fourier stress method was applied to deal with the problem of plane thermal stress, and a computing formula was given. As an example, we set up a variate temperature field to describe the uplifted upper mantle in Bozhong area of China, and the computing results shows that the maximum value of thermal plane shear stress is up to nearly 7x10 7 P α in two regions of this area. Since the Bohai earthquake (18 July, 1969, M s = 7.4) occurred at the edge of one of them and Tangshan earthquake (28 July, 1976, M s = 7.8) within another, their occurrences can be related reasonably to the thermal stress. (author). 15 refs, 7 figs

  6. Local quantum thermal susceptibility

    Science.gov (United States)

    De Pasquale, Antonella; Rossini, Davide; Fazio, Rosario; Giovannetti, Vittorio

    2016-01-01

    Thermodynamics relies on the possibility to describe systems composed of a large number of constituents in terms of few macroscopic variables. Its foundations are rooted into the paradigm of statistical mechanics, where thermal properties originate from averaging procedures which smoothen out local details. While undoubtedly successful, elegant and formally correct, this approach carries over an operational problem, namely determining the precision at which such variables are inferred, when technical/practical limitations restrict our capabilities to local probing. Here we introduce the local quantum thermal susceptibility, a quantifier for the best achievable accuracy for temperature estimation via local measurements. Our method relies on basic concepts of quantum estimation theory, providing an operative strategy to address the local thermal response of arbitrary quantum systems at equilibrium. At low temperatures, it highlights the local distinguishability of the ground state from the excited sub-manifolds, thus providing a method to locate quantum phase transitions. PMID:27681458

  7. Engineering problems of tandem-mirror reactors

    International Nuclear Information System (INIS)

    Moir, R.W.; Barr, W.L.; Boghosian, B.M.

    1981-01-01

    We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper

  8. TIGER: Development of Thermal Gradient Compensation Algorithms and Techniques

    Science.gov (United States)

    Hereford, James; Parker, Peter A.; Rhew, Ray D.

    2004-01-01

    In a wind tunnel facility, the direct measurement of forces and moments induced on the model are performed by a force measurement balance. The measurement balance is a precision-machined device that has strain gages at strategic locations to measure the strain (i.e., deformations) due to applied forces and moments. The strain gages convert the strain (and hence the applied force) to an electrical voltage that is measured by external instruments. To address the problem of thermal gradients on the force measurement balance NASA-LaRC has initiated a research program called TIGER - Thermally-Induced Gradients Effects Research. The ultimate goals of the TIGER program are to: (a) understand the physics of the thermally-induced strain and its subsequent impact on load measurements and (b) develop a robust thermal gradient compensation technique. This paper will discuss the impact of thermal gradients on force measurement balances, specific aspects of the TIGER program (the design of a special-purpose balance, data acquisition and data analysis challenges), and give an overall summary.

  9. Implementation of heaters on thermally actuated spacecraft mechanisms

    Science.gov (United States)

    Busch, John D.; Bokaie, Michael D.

    1994-01-01

    This paper presents general insight into the design and implementation of heaters as used in actuating mechanisms for spacecraft. Problems and considerations that were encountered during development of the Deep Space Probe and Science Experiment (DSPSE) solar array release mechanism are discussed. Obstacles included large expected fluctuations in ambient temperature, variations in voltage supply levels outgassing concerns, heater circuit design, materials selection, and power control options. Successful resolution of these issues helped to establish a methodology which can be applied to many of the heater design challenges found in thermally actuated mechanisms.

  10. Challenges in obesity research.

    Science.gov (United States)

    Palou, Andreu; Bonet, M Luisa

    2013-09-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors--often interrelated and many of them still unknown or poorly understood--can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regarding basic aspects of obesity and emerging science for its control, including brown adipose tissue thermogenesis and browning of white fat as possible therapeutic targets for obesity, the influence of the microbioma, and genetics, epigenetics, nutrigenomics and nutrigenetics of obesity. We also highlight hot topics in relation to food and lifestyle as determinants of obesity, including the brain mechanisms underlying environmental motivation to eat, the biological control of spontaneous physical activity, the possible role of concrete foods and food components, and the importance of early life nutrition and environment. Challenges regarding the connections of obesity with other alterations and pathologies are also briefly addressed, as well as social and economical challenges in relation to healthy food production and lifestyle for the prevention of obesity, and technological challenges in obesity research and management. The objective is to give a panoramic of advances accomplished and still ahead relevant to the different stakeholders engaged in understanding and combating obesity. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  11. Thermal expansion

    International Nuclear Information System (INIS)

    Yun, Y.

    2015-01-01

    Thermal expansion of fuel pellet is an important property which limits the lifetime of the fuels in reactors, because it affects both the pellet and cladding mechanical interaction and the gap conductivity. By fitting a number of available measured data, recommended equations have been presented and successfully used to estimate thermal expansion coefficient of the nuclear fuel pellet. However, due to large scatter of the measured data, non-consensus data have been omitted in formulating the equations. Also, the equation is strongly governed by the lack of appropriate experimental data. For those reasons, it is important to develop theoretical methodologies to better describe thermal expansion behaviour of nuclear fuel. In particular, first-principles and molecular dynamics simulations have been certainly contributed to predict reliable thermal expansion without fitting the measured data. Furthermore, the two theoretical techniques have improved on understanding the change of fuel dimension by describing the atomic-scale processes associated with lattice expansion in the fuels. (author)

  12. Transf ormation thermotics and the manipulation of thermal energy

    Institute of Scientific and Technical Information of China (English)

    Xiangfan Xu; Baowen Li

    2017-01-01

    Thermal energy has been proposed to have ever greater potential for human beings if the heat carriers, pho-nons can be controlled in micron-scale as easy as its counterpart, electrons in solid. However, it is a challenge to control phonons due to its relatively short wavelength, which is in the order of a few nanometers to a few tens of nanometers. Alternatively, in macroscopical scale, functional thermal materials are used to control thermal energy. The transfor-mation of macroscopical thermal diffusion equation is proposed to obtain the asymmetrical thermal conductivity in real space. This new type of thermal functional materials helps to control heat flow and to realize thermal cloak and thermal camouflage. In this review, we summarize the recent advances in constructing thermal functional materials (also called thermal metamaterials). In SecⅠ, we discussed the history of functional materials and the principles of constructing thermal functional materials , special focus was given to the thermal cloak, followed by the realization of thermal cloak in SecⅡ.Thermal camouflage, based on the realization of thermal cloak, was discussed in SecⅢ, which is proposed to have great potentials in military usage. We stressed both the principle and practical based challenges in thermal cloak and thermal camouflage in SecⅣ, in which outlooks were also given. It is worth noting that thermal transports consist of thermal conduction, thermal convection and thermal radiation. Recent progresses on thermal functional materials are based on the transformation of thermotics, i.e. spacial distortion of thermal conducting path, leaving thermal convection and thermal radiation untouched. We hope, though this review paper, to encourage more researchers in China to engage in this field, and to accelerate the practical usage of thermal cloak and thermal camouflage.

  13. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    Xu Feng; Wen Ting; Lu Tianjian; Seffen Keith

    2008-01-01

    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

  14. Thermal physics kinetic theory and thermodynamics

    CERN Document Server

    Singh, Devraj; Yadav, Raja Ram

    2016-01-01

    THERMAL PHYSICS: Kinetic Theory and Thermodynamics is designed for undergraduate course in Thermal Physics and Thermodynamics. The book provides thorough understanding of the fundamental principles of the concepts in Thermal Physics. The book begins with kinetic theory, then moves on liquefaction, transport phenomena, the zeroth, first, second and third laws, thermodynamics relations and thermal conduction. The book concluded with radiation phenomenon. KEY FEATURES: * Include exercises * Short Answer Type Questions * Long Answer Type Questions * Numerical Problems * Multiple Choice Questions

  15. Dispersion stability of thermal nanofluids

    Directory of Open Access Journals (Sweden)

    Fan Yu

    2017-10-01

    Full Text Available Thermal nanofluids, the engineered fluids with dispersed functional nanoparticles, have exhibited extraordinary thermophysical properties and added functionalities, and thus have enabled a broad range of important applications. The poor dispersion stability of thermal nanofluids, however, has been considered as a long-existing issue that limits their further development and practical application. This review overviews the recent efforts and progresses in improving the dispersion stability of thermal nanofluids such as mechanistic understanding of dispersion behavior of nanofluids, examples of both water-based and oil-based nanofluids, strategies to stabilize nanofluids, and characterization techniques for dispersion behavior of nanofluids. Finally, on-going research needs, and possible solutions to research challenges and future research directions in exploring stably dispersed thermal nanofluids are discussed. Keywords: Thermal nanofluids, Dispersion, Aggregation, Electrostatic stabilization, Steric stabilization

  16. Explaining the Mind: Problems, Problems

    OpenAIRE

    Harnad, Stevan

    2001-01-01

    The mind/body problem is the feeling/function problem: How and why do feeling systems feel? The problem is not just "hard" but insoluble (unless one is ready to resort to telekinetic dualism). Fortunately, the "easy" problems of cognitive science (such as the how and why of categorization and language) are not insoluble. Five books (by Damasio, Edelman/Tononi...

  17. Managing the Mars Science Laboratory Thermal Vacuum Test for Safety and Success

    Science.gov (United States)

    Evans, Jordan P.

    2010-01-01

    The Mars Science Laboratory is a NASA/JPL mission to send the next generation of rover to Mars. Originally slated for launch in 2009, development problems led to a delay in the project until the next launch opportunity in 2011. Amidst the delay process, the Launch/Cruise Solar Thermal Vacuum Test was undertaken as risk reduction for the project. With varying maturity and capabilities of the flight and ground systems, undertaking the test in a safe manner presented many challenges. This paper describes the technical and management challenges and the actions undertaken that led to the ultimate safe and successful execution of the test.

  18. Thermal Properties and Thermal Analysis:

    Science.gov (United States)

    Kasap, Safa; Tonchev, Dan

    The chapter provides a summary of the fundamental concepts that are needed to understand the heat capacity C P, thermal conductivity κ, and thermal expansion coefficient α L of materials. The C P, κ, and α of various classes of materials, namely, semiconductors, polymers, and glasses, are reviewed, and various typical characteristics are summarized. A key concept in crystalline solids is the Debye theory of the heat capacity, which has been widely used for many decades for calculating the C P of crystals. The thermal properties are interrelated through Grüneisen's theorem. Various useful empirical rules for calculating C P and κ have been used, some of which are summarized. Conventional differential scanning calorimetry (DSC) is a powerful and convenient thermal analysis technique that allows various important physical and chemical transformations, such as the glass transition, crystallization, oxidation, melting etc. to be studied. DSC can also be used to obtain information on the kinetics of the transformations, and some of these thermal analysis techniques are summarized. Temperature-modulated DSC, TMDSC, is a relatively recent innovation in which the sample temperature is ramped slowly and, at the same time, sinusoidally modulated. TMDSC has a number of distinct advantages compared with the conventional DSC since it measures the complex heat capacity. For example, the glass-transition temperature T g measured by TMDSC has almost no dependence on the thermal history, and corresponds to an almost step life change in C P. The new Tzero DSC has an additional thermocouple to calibrate better for thermal lags inherent in the DSC measurement, and allows more accurate thermal analysis.

  19. What can recycling in thermal reactors accomplish?

    International Nuclear Information System (INIS)

    Piet, Steven J.; Matthern, Gretchen E.; Jacobson, Jacob J.

    2007-01-01

    Thermal recycle provides several potential benefits when used as stop-gap, mixed, or backup recycling to recycling in fast reactors. These three roles involve a mixture of thermal and fast recycling; fast reactors are required to some degree at some time. Stop-gap uses thermal reactors only until fast reactors are adequately deployed and until any thermal-recycle-only facilities have met their economic lifetime. Mixed uses thermal and fast reactors symbiotically for an extended period of time. Backup uses thermal reactors only if problems later develop in the fast reactor portion of a recycling system. Thermal recycle can also provide benefits when used as pure thermal recycling, with no intention to use fast reactors. However, long term, the pure thermal recycling approach is inadequate to meet several objectives. (authors)

  20. What can Recycling in Thermal Reactors Accomplish?

    International Nuclear Information System (INIS)

    Steven Piet; Gretchen E. Matthern; Jacob J. Jacobson

    2007-01-01

    Thermal recycle provides several potential benefits when used as stop-gap, mixed, or backup recycling to recycling in fast reactors. These three roles involve a mixture of thermal and fast recycling; fast reactors are required to some degree at some time. Stop-gap uses thermal reactors only until fast reactors are adequately deployed and until any thermal-recycle-only facilities have met their economic lifetime. Mixed uses thermal and fast reactors symbiotically for an extended period of time. Backup uses thermal reactors only if problems later develop in the fast reactor portion of a recycling system. Thermal recycle can also provide benefits when used as pure thermal recycling, with no intention to use fast reactors. However, long term, the pure thermal recycling approach is inadequate to meet several objectives

  1. Prostate Problems

    Science.gov (United States)

    ... know the exact cause of your prostate problem. Prostatitis The cause of prostatitis depends on whether you ... prostate problem in men older than age 50. Prostatitis If you have a UTI, you may be ...

  2. General problems

    International Nuclear Information System (INIS)

    2005-01-01

    This article presents the general problems as natural disasters, consequences of global climate change, public health, the danger of criminal actions, the availability to information about problems of environment

  3. Learning Problems

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Learning Problems KidsHealth / For Kids / Learning Problems What's in ... for how to make it better. What Are Learning Disabilities? Learning disabilities aren't contagious, but they ...

  4. Ankle Problems

    Science.gov (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Ankle ProblemsFollow this chart for more information about problems that can cause ankle pain. Our trusted Symptom Checker is written and ...

  5. Coordinated Exploration for Grand Challenges

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph

    2016-01-01

    Grand challenges are among the most complex problems for modern societies. Many governments and foundations provide substantial resources to encourage the search for solutions. Due to the significance of these problems, organizations often form partnerships in what we call search consortia to eng...

  6. Problems in abstract algebra

    CERN Document Server

    Wadsworth, A R

    2017-01-01

    This is a book of problems in abstract algebra for strong undergraduates or beginning graduate students. It can be used as a supplement to a course or for self-study. The book provides more variety and more challenging problems than are found in most algebra textbooks. It is intended for students wanting to enrich their learning of mathematics by tackling problems that take some thought and effort to solve. The book contains problems on groups (including the Sylow Theorems, solvable groups, presentation of groups by generators and relations, and structure and duality for finite abelian groups); rings (including basic ideal theory and factorization in integral domains and Gauss's Theorem); linear algebra (emphasizing linear transformations, including canonical forms); and fields (including Galois theory). Hints to many problems are also included.

  7. Engineering-Based Thermal CFD Simulations on Massive Parallel Systems

    KAUST Repository

    Frisch, Jérôme

    2015-05-22

    The development of parallel Computational Fluid Dynamics (CFD) codes is a challenging task that entails efficient parallelization concepts and strategies in order to achieve good scalability values when running those codes on modern supercomputers with several thousands to millions of cores. In this paper, we present a hierarchical data structure for massive parallel computations that supports the coupling of a Navier–Stokes-based fluid flow code with the Boussinesq approximation in order to address complex thermal scenarios for energy-related assessments. The newly designed data structure is specifically designed with the idea of interactive data exploration and visualization during runtime of the simulation code; a major shortcoming of traditional high-performance computing (HPC) simulation codes. We further show and discuss speed-up values obtained on one of Germany’s top-ranked supercomputers with up to 140,000 processes and present simulation results for different engineering-based thermal problems.

  8. The NASA Langley Multidisciplinary Uncertainty Quantification Challenge

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.

    2014-01-01

    This paper presents the formulation of an uncertainty quantification challenge problem consisting of five subproblems. These problems focus on key aspects of uncertainty characterization, sensitivity analysis, uncertainty propagation, extreme-case analysis, and robust design.

  9. Environmental challenge

    International Nuclear Information System (INIS)

    Conable, B.; Warford, J.; Partow, Z.; Lutz, E.; Munasinghe, M.

    1991-09-01

    The contents include the following: Development and the Environment: A Global Balance; Evolution of the World Bank's Environmental Policy; Accounting for the Environment; Public Policy and the Environment; Managing Drylands; Environmental Action Plans in Africa; Agroforestry in Sub-Saharan Africa; Irrigation and the Environmental Challenge; Curbing Pollution in Developing Countries; Global Warming and the Developing World; and The Global Environment Facility

  10. Challenging Identities

    DEFF Research Database (Denmark)

    depends on the conceptual or ideological constellation in which it takes part. This volume on one hand demonstrates the role of notions of identity in a variety of European contexts, and on the other hand highlights how there may be reasons to challenge the use of the term and corresponding social...

  11. Overcoming challenges

    Medline Plus

    Full Text Available ... Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths ...

  12. Overcoming challenges

    Medline Plus

    Full Text Available ... we are What we do Programs and activities Work with us Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  13. Solar thermal power plants

    International Nuclear Information System (INIS)

    Schnatbaum, L.

    2009-01-01

    The solar thermal power plant technology, the opportunities it presents and the developments in the market are outlined. The focus is on the technology of parabolic trough power plants, a proven technology for solar power generation on a large scale. In a parabolic trough power plant, trough-shaped mirrors concentrate the solar irradiation onto a pipe in the focal line of the collector. The thermal energy thus generated is used for electricity generation in a steam turbine. Parabolic trough plants can be combined with thermal storage and fossil or biomass fired heat exchangers to generate electricity even when the sun is not shining. Solar Millennium AG in Erlangen has developed the first power plant of this kind in Europe. After two years of construction the plant started operation in Southern Spain in 2008. This one and its sister projects are important steps leading the way for the whole market. The paper also covers the technological challenges, the key components used and the research and development activities concerning this technology. Solar thermal power plants are ideal for covering peak and medium loads in power grids. In hybrid operation they can also cover base-load. The Solar Chimney power plant, another striking technology for the conversion of solar into electric energy, is described briefly. The paper concludes with a look at the future - the import of solar energy from the deserts of North Africa to central Europe. (author)

  14. Thermal comfort

    DEFF Research Database (Denmark)

    d’Ambrosio Alfano, Francesca Romana; Olesen, Bjarne W.; Palella, Boris Igor

    2014-01-01

    Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking...... into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used...... under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers...

  15. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  16. Matrix thermalization

    International Nuclear Information System (INIS)

    Craps, Ben; Evnin, Oleg; Nguyen, Kévin

    2017-01-01

    Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.

  17. Matrix thermalization

    Science.gov (United States)

    Craps, Ben; Evnin, Oleg; Nguyen, Kévin

    2017-02-01

    Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.

  18. Matrix thermalization

    Energy Technology Data Exchange (ETDEWEB)

    Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Evnin, Oleg [Department of Physics, Faculty of Science, Chulalongkorn University, Thanon Phayathai, Pathumwan, Bangkok 10330 (Thailand); Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Nguyen, Kévin [Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium)

    2017-02-08

    Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.

  19. Multi-objective superstructure-free synthesis and optimization of thermal power plants

    International Nuclear Information System (INIS)

    Wang, Ligang; Lampe, Matthias; Voll, Philip; Yang, Yongping; Bardow, André

    2016-01-01

    The merits of superstructure-free synthesis are demonstrated for bi-objective design of thermal power plants. The design of thermal power plants is complex and thus best solved by optimization. Common optimization methods require specification of a superstructure which becomes a tedious and error-prone task for complex systems. Superstructure specification is avoided by the presented superstructure-free approach, which is shown to successfully solve the design task yielding a high-quality Pareto front of promising structural alternatives. The economic objective function avoids introducing infinite numbers of units (e.g., turbine, reheater and feedwater preheater) as favored by pure thermodynamic optimization. The number of feasible solutions found per number of mutation tries is still high even after many generations but declines after introducing highly-nonlinear cost functions leading to challenging MINLP problems. The identified Pareto-optimal solutions tend to employ more units than found in modern power plants indicating the need for cost functions to reflect current industrial practice. In summary, the multi-objective superstructure-free synthesis framework is a robust approach for very complex problems in the synthesis of thermal power plants. - Highlights: • A generalized multi-objective superstructure-free synthesis framework for thermal power plants is presented. • The superstructure-free synthesis framework is comprehensively evaluated by complex bi-objective synthesis problems. • The proposed framework is effective to explore the structural design space even for complex problems.

  20. LMFBR thermal-striping evaluation

    International Nuclear Information System (INIS)

    Brunings, J.E.

    1982-10-01

    Thermal striping is defined as the fluctuating temperature field that is imposed on a structure when fluid streams at different temperatures mix in the vicinity of the structure surface. Because of the uncertainty in structural damage in LMFBR structures subject to thermal striping, EPRI has funded an effort for the Rockwell International Energy Systems Group to evaluate this problem. This interim report presents the following information: (1) a Thermal Striping Program Plan which identifies areas of analytic and experimental needs and presents a program of specific tasks to define damage experienced by ordinary materials of construction and to evaluate conservatism in the existing approach; (2) a description of the Thermal Striping Test Facility and its operation; and (3) results from the preliminary phase of testing to characterize the fluid environment to be applied in subsequent thermal striping damage experiments

  1. Applying Systems Engineering on Energy Challenges

    NARCIS (Netherlands)

    Safi, J.; Muller, G.; Bonnema, Gerrit Maarten

    2012-01-01

    Systems engineering is a discipline with methods and techniques to address complex problems. We want to study how Systems Engineering methods can help to address today's grand challenges, such as the energy problem. The first step is problem definition which aims at articulating the problem in its

  2. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part...... of the so-called ‘mobility turn’ within social science. The perspective is illustrative for the research efforts at the Centre for Mobility and Urban Studies (C-MUS), Aalborg University. The article presents the contours of a theoretical perspective meeting the challenges to research into contemporary urban...... mobilities. In particular the article discusses 1) the physical city, its infrastructures and technological hardware/software, 2) policies and planning strategies for urban mobility and 3) the lived everyday life in the city and the region....

  3. Sociale problemer

    DEFF Research Database (Denmark)

    Christensen, Anders Bøggild; Rasmussen, Tove; Bundesen, Peter Verner

    Sociale problemer kan betragtes som selve udgangspunktet for socialt arbejde, hvor ambitionen er at råde bod på problemerne og sikre, at udsatte borgere får en bedre tilværelse. Det betyder også, at diskussionen af sociale problemer er afgørende for den sociale grundfaglighed. I denne bog sætter en...... række fagfolk på tværs af det danske socialfaglige felt fokus på sociale problemer. Det diskuteres, hvad vi overhovedet forstår ved sociale problemer, hvordan de opstår, hvilke konsekvenser de har, og ikke mindst hvordan man som fagprofessionel håndterer sociale problemer i det daglige arbejde. Bogen er...... skrevet som lærebog til professionsuddannelser, hvor sociale problemer udgør en dimension, bl.a. socialrådgiver-, pædagog- og sygeplejerskeuddannelserne....

  4. ANALYSIS OVERHEATING PROBLEMS OF ELECTRIC MOTOR BY TYPE DK-409 AND MOTOR – DRIVEN COMPRESSOR BY TYPE (EK – 7B OF CONTINUOUS CURRENT LOCOMOTIVE BY TYPE (ER – 1, ER – 2 WITH USING THE THERMAL SYSTEM OF COMPENSATION

    Directory of Open Access Journals (Sweden)

    R. V. Krasnov

    2010-11-01

    Full Text Available The article shows the method of investigation of thermal processes occurring in the electric compressor motor of rolling stock to determine the values of overheating, which will later be used to assess their impact on the state of isolation.

  5. About some types of constraints in problems of routing

    Science.gov (United States)

    Petunin, A. A.; Polishuk, E. G.; Chentsov, A. G.; Chentsov, P. A.; Ukolov, S. S.

    2016-12-01

    Many routing problems arising in different applications can be interpreted as a discrete optimization problem with additional constraints. The latter include generalized travelling salesman problem (GTSP), to which task of tool routing for CNC thermal cutting machines is sometimes reduced. Technological requirements bound to thermal fields distribution during cutting process are of great importance when developing algorithms for this task solution. These requirements give rise to some specific constraints for GTSP. This paper provides a mathematical formulation for the problem of thermal fields calculating during metal sheet thermal cutting. Corresponding algorithm with its programmatic implementation is considered. The mathematical model allowing taking such constraints into account considering other routing problems is discussed either.

  6. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

  7. Hearing Problems

    Science.gov (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Hearing ProblemsLoss in the ability to hear or discriminate ... This flow chart will help direct you if hearing loss is a problem for you or a ...

  8. Thermal insulation

    International Nuclear Information System (INIS)

    Durston, J.G.; Birch, W.; Facer, R.I.; Stuart, R.A.

    1977-01-01

    Reference is made to liquid metal cooled nuclear reactors. In the arrangement described the reactor vessel is clad with thermal insulation comprising a layer of insulating blocks spaced from the wall and from each other; each block is rigidly secured to the wall, and the interspaces are substantially closed against convectional flow of liquid by resilient closure members. A membrane covering is provided for the layer of blocks, with venting means to allow liquid from the reactor vessel to penetrate between the covering and the layer of blocks. The membrane covering may comprise a stainless steel sheet ribbed in orthogonal pattern to give flexibility for the accommodation of thermal strain. The insulating blocks may be comprised of stainless steel or cellular or porous material and may be hollow shells containing ceramic material or gas fillings. (U.K.)

  9. Solar thermal

    International Nuclear Information System (INIS)

    Jones, J.

    2006-01-01

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m 3 - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become increasingly important as

  10. Solar thermal

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.

    2006-07-15

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m{sup 3} - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become

  11. The Problem Revisited

    DEFF Research Database (Denmark)

    Ovesen, Nis

    2015-01-01

    Problem-based learning (PBL) is becoming increasingly popular in design educations, but how is it taught and practiced? This paper presents a case study of a three-day workshop that has the purpose of introducing PBL to design students. A theoretical background on PBL and problems in design is es...... is established and is backing up the case study. The study shows that design engineering and architectural students without experience in PBL in general finds the approach to be beneficial when working on a design challenge in a student team....

  12. Advanced thermal management technologies for defense electronics

    Science.gov (United States)

    Bloschock, Kristen P.; Bar-Cohen, Avram

    2012-05-01

    Thermal management technology plays a key role in the continuing miniaturization, performance improvements, and higher reliability of electronic systems. For the past decade, and particularly, the past 4 years, the Defense Advanced Research Projects Agency (DARPA) has aggressively pursued the application of micro- and nano-technology to reduce or remove thermal constraints on the performance of defense electronic systems. The DARPA Thermal Management Technologies (TMT) portfolio is comprised of five technical thrust areas: Thermal Ground Plane (TGP), Microtechnologies for Air-Cooled Exchangers (MACE), NanoThermal Interfaces (NTI), Active Cooling Modules (ACM), and Near Junction Thermal Transport (NJTT). An overview of the TMT program will be presented with emphasis on the goals and status of these efforts relative to the current State-of-the-Art. The presentation will close with future challenges and opportunities in the thermal management of defense electronics.

  13. Conjugate problems in convective heat transfer

    CERN Document Server

    Dorfman, Abram S

    2009-01-01

    The conjugate heat transfer (CHT) problem takes into account the thermal interaction between a body and fluid flowing over or through it, a key consideration in both mechanical and aerospace engineering. Presenting more than 100 solutions of non-isothermal and CHT problems, this title considers the approximate solutions of CHT problems.

  14. Data Challenges

    CERN Multimedia

    McCubbin, N A

    Some two years ago we planned a series of Data Challenges starting at the end of 2001. At the time, that seemed to be comfortingly far in the future... Well, as the saying goes, doesn't time fly when you are having fun! ATLAS Computing is now deep in the throes of getting the first Data Challenge (DC0) up and running. One of the main aims of DC0 is to have a software 'release' in which we can generate full physics events, track all particles through the detector, simulate the detector response, reconstruct the event, and study it, with appropriate data storage en route. As all software is "always 95% ready" (!), we have been able to do most of this, more or less, for some time. But DC0 forces us to have everything working, together, at the same time: a reality check. DC0 should finish early next year, and it will be followed almost immediately afterwards by DC1 (DC0 was foreseen as the 'check' for DC1). DC1 will last into the middle of 2002, and has two major goals. The first is generation, simulation, and r...

  15. Thermal shale fracturing simulation using the Cohesive Zone Method (CZM)

    KAUST Repository

    Enayatpour, Saeid; van Oort, Eric; Patzek, Tadeusz

    2018-01-01

    Extensive research has been conducted over the past two decades to improve hydraulic fracturing methods used for hydrocarbon recovery from tight reservoir rocks such as shales. Our focus in this paper is on thermal fracturing of such tight rocks to enhance hydraulic fracturing efficiency. Thermal fracturing is effective in generating small fractures in the near-wellbore zone - or in the vicinity of natural or induced fractures - that may act as initiation points for larger fractures. Previous analytical and numerical results indicate that thermal fracturing in tight rock significantly enhances rock permeability, thereby enhancing hydrocarbon recovery. Here, we present a more powerful way of simulating the initiation and propagation of thermally induced fractures in tight formations using the Cohesive Zone Method (CZM). The advantages of CZM are: 1) CZM simulation is fast compared to similar models which are based on the spring-mass particle method or Discrete Element Method (DEM); 2) unlike DEM, rock material complexities such as scale-dependent failure behavior can be incorporated in a CZM simulation; 3) CZM is capable of predicting the extent of fracture propagation in rock, which is more difficult to determine in a classic finite element approach. We demonstrate that CZM delivers results for the challenging fracture propagation problem of similar accuracy to the eXtended Finite Element Method (XFEM) while reducing complexity and computational effort. Simulation results for thermal fracturing in the near-wellbore zone show the effect of stress anisotropy in fracture propagation in the direction of the maximum horizontal stress. It is shown that CZM can be used to readily obtain the extent and the pattern of induced thermal fractures.

  16. Thermal shale fracturing simulation using the Cohesive Zone Method (CZM)

    KAUST Repository

    Enayatpour, Saeid

    2018-05-17

    Extensive research has been conducted over the past two decades to improve hydraulic fracturing methods used for hydrocarbon recovery from tight reservoir rocks such as shales. Our focus in this paper is on thermal fracturing of such tight rocks to enhance hydraulic fracturing efficiency. Thermal fracturing is effective in generating small fractures in the near-wellbore zone - or in the vicinity of natural or induced fractures - that may act as initiation points for larger fractures. Previous analytical and numerical results indicate that thermal fracturing in tight rock significantly enhances rock permeability, thereby enhancing hydrocarbon recovery. Here, we present a more powerful way of simulating the initiation and propagation of thermally induced fractures in tight formations using the Cohesive Zone Method (CZM). The advantages of CZM are: 1) CZM simulation is fast compared to similar models which are based on the spring-mass particle method or Discrete Element Method (DEM); 2) unlike DEM, rock material complexities such as scale-dependent failure behavior can be incorporated in a CZM simulation; 3) CZM is capable of predicting the extent of fracture propagation in rock, which is more difficult to determine in a classic finite element approach. We demonstrate that CZM delivers results for the challenging fracture propagation problem of similar accuracy to the eXtended Finite Element Method (XFEM) while reducing complexity and computational effort. Simulation results for thermal fracturing in the near-wellbore zone show the effect of stress anisotropy in fracture propagation in the direction of the maximum horizontal stress. It is shown that CZM can be used to readily obtain the extent and the pattern of induced thermal fractures.

  17. The Inverse Problem of Identification of Hydrogen Permeability Model

    Directory of Open Access Journals (Sweden)

    Yury V. Zaika

    2018-01-01

    Full Text Available One of the technological challenges for hydrogen materials science is the currently active search for structural materials with important applications (including the ITER project and gas-separation plants. One had to estimate the parameters of diffusion and sorption to numerically model the different scenarios and experimental conditions of the material usage (including extreme ones. The article presents boundary value problems of hydrogen permeability and thermal desorption with dynamical boundary conditions. A numerical method is developed for TDS spectrum simulation, where only integration of a nonlinear system of low order ordinary differential equations is required. The main final output of the article is a noise-resistant algorithm for solving the inverse problem of parametric identification for the aggregated experiment where desorption and diffusion are dynamically interrelated (without the artificial division of studies into the diffusion limited regime (DLR and the surface limited regime (SLR.

  18. Problem Posing

    OpenAIRE

    Šilhavá, Marie

    2009-01-01

    This diploma thesis concentrates on problem posing from the students' point of view. Problem posing can be either seen as a teaching method which can be used in the class, or it can be used as a tool for researchers or teachers to assess the level of students' understanding of the topic. In my research, I compare three classes, one mathematics specialist class and two generalist classes, in their ability of problem posing. As an assessment tool it seemed that mathemathics specialists were abl...

  19. Application of self-adaptive procedure to the thermal problems analysis under steady-state and transient regimens; Aplicacao de procedimento auto-adaptativo na analise de problemas termicos no regime permanente e transiente

    Energy Technology Data Exchange (ETDEWEB)

    Lyra, Paulo Roberto Maciel [Pernambuco Univ., Recife, PE (Brazil). Dept. de Engenharia Civil

    1991-12-31

    This work describes a procedure for the adaptive time dependent Finite Element Method using an automatic mesh refinement (H-Version) that efficiently reduces estimated errors ( a posteriori) below pre-assigned limits. Classical model problem for steady-state heat transfer are investigated, and the results are compared with the analytical solution. Then some typical time-dependent problem are qualitatively analysed. (author) 10 refs., 7 figs.

  20. Thermal cycling fatigue of organic thermal interface materials using a thermal-displacement measurement technique

    Science.gov (United States)

    Steill, Jason Scott

    The long term reliability of polymer-based thermal interface materials (TIM) is essential for modern electronic packages which require robust thermal management. The challenge for today's materials scientists and engineers is to maximize the heat flow from integrated circuits through a TIM and out the heat sink. Thermal cycling of the electronic package and non-uniformity in the heat flux with respect to the plan area can lead to void formation and delamination which re-introduces inefficient heat transfer. Measurement and understanding at the nano-scale is essential for TIM development. Finding and documenting the evolution of the defects is dependent upon a full understanding of the thermal probes response to changing environmental conditions and the effects of probe usage. The response of the thermal-displacement measurement technique was dominated by changes to the environment. Accurate measurement of the thermal performance was hindered by the inability to create a model system and control the operating conditions. This research highlights the need for continued study into the probe's thermal and mechanical response using tightly controlled test conditions.

  1. Popular Problems

    DEFF Research Database (Denmark)

    Skovhus, Randi Boelskifte; Thomsen, Rie

    2017-01-01

    This article introduces a method to critical reviews and explores the ways in which problems have been formulated in knowledge production on career guidance in Denmark over a 10-year period from 2004 to 2014. The method draws upon the work of Bacchi focussing on the ‘What's the problem represented...... to be’ (WPR) approach. Forty-nine empirical studies on Danish youth career guidance were included in the study. An analysis of the issues in focus resulted in nine problem categories. One of these, ‘targeting’, is analysed using the WPR approach. Finally, the article concludes that the WPR approach...... provides a constructive basis for a critical analysis and discussion of the collective empirical knowledge production on career guidance, stimulating awareness of problems and potential solutions among the career guidance community....

  2. Sleep Problems

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... 101 KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...

  3. Mouth Problems

    Science.gov (United States)

    ... such as sores, are very common. Follow this chart for more information about mouth problems in adults. ... cancers. See your dentist if sharp or rough teeth or dental work are causing irritation. Start OverDiagnosisThis ...

  4. Kidney Problems

    Science.gov (United States)

    ... our e-newsletter! Aging & Health A to Z Kidney Problems Basic Facts & Information The kidneys are two ... kidney (renal) diseases are called nephrologists . What are Kidney Diseases? For about one-third of older people, ...

  5. Challenging makerspaces

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Thestrup, Klaus

    This paper takes its departure in the EU-project MakEY - Makerspaces in the early years – enhancing digital literacy and creativity that is part of a H2020 RISE-program and is running January 2017 - June 2019. Here digital literacy and creative skills of young children between the age of 3......-8 will be developed through participation in creative activities in specially-designed spaces termed ‘makerspaces’. This paper discusses, develops and challenges this term in relation to Danish pedagogical traditions, to expanding makerspaces onto the internet and on how to combine narratives and construction....... The Danish part of the project will be undertaken by a small network of partners: DOKK1, a public library and open urban space in Aarhus, that is experimenting with different kind of makerspaces, spaces and encounters between people, The LEGO-LAB situated at Computer Science, Aarhus University, that has...

  6. Experimental and Numerical Study of Effect of Thermal Management on Storage Capacity of the Adsorbed Natural Gas Vessel

    KAUST Repository

    Ybyraiymkul, Doskhan; Ng, Kim Choon; Кaltayev, Aidarkhan

    2017-01-01

    One of the main challenges in the adsorbed natural gas (ANG) storage system is the thermal effect of adsorption, which significantly lowers storage capacity. These challenges can be solved by efficient thermal management system. In this paper

  7. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  8. Integration of thickener underflow into thermal dryer circuit. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McClaine, A.W.; Breault, R.W.

    1998-12-31

    A large number of coal preparation plants in the United States are troubled with coal fines and associated plant operation problems. As part of their process, these plants use thermal dryers for producing product coal, cyclones for first-stage recovery of coal fines, and wet scrubbers for the second-stage removal of coal fines carry-over from the dryer exhaust gas. The first challenge for these plants is to recover the clean ultra-fine coal captured in the scrubbers rather than to dispose of it in settling ponds. The second challenge is to mitigate the over-dry fine coal dusting problems in the dryer product. Prior to the completion of this program, the difficulties of the first challenge involving the recovery and use of fine clean coal from the thermal dryer scrubber effluent had not been solved. The second challenge, controlling fine coal dusting, was previously met by applying a solution of surfactants and process water to the over-dry coal fraction. As a result of the demonstration provided by the performance of this program, the implementation of a simple process improvement, involving the use of a thickener in combination with a belt press, simultaneously solved both challenges: the de-dusting and the dryer scrubber effluent recovery issues. The objective of this project was to: (1) Use a clean coal thickener with a squeeze belt press to recover the ultra-fine coal in dryer scrubber effluent; (2) Demonstrate that the coal-water mixture (CWM) produced from scrubber sludge of a thermal dryer can be used as a dust suppressant. The thickener/belt press system has increased the production of JWRI Mine Number 4 by approximately 0.7%. This production increase was accomplished by recovering and re-using 3 metric tons/hr (3.3 tons/hr) of coal fines that were previously sent to holding ponds, returning this as a 50% CWM to de-dust the 430 metric tons/hr (470 tons/hr) of existing dryer production.

  9. Diagnostic interface problems on TFTR

    International Nuclear Information System (INIS)

    Goldfarb, S.

    1977-01-01

    Diagnostic equipment on TFTR has functional interfaces with many machine systems. Salient requirements include plasma access, environmental resistance to thermal, magnetic and radiation effects, automated data acquisition and controls, remote handling and personnel safety. Problems imposed by these requirements and the solutions being considered are described

  10. The unmasking of thermal Goldstone bosons

    International Nuclear Information System (INIS)

    Buchholz, D.; Bros, J.

    1996-08-01

    The problem of extracting the modes of Goldstone bosons from a thermal background is reconsidered in the framework of relativistic quantum field theory. It is shown that in the case of spontaneous breakdown of an internal bosonic symmetry a recently established decomposition of thermal correlation functions contains certain specific contributions which can be attributed to a scalar particle of zero mass. (orig.)

  11. Glomar challenger

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, J P

    1969-01-01

    The Glomar Challenger has a length of 400 ft, a 65-ft beam, and a depth of 27 ft 6-in. She has a draft of 20 ft with a gross displacement of 10,500 long tons. The principal specifications of the vessel are tabulated. To achieve dynamic positioning, 4 fixed thrusters and the vessel's 2 propulsion screws are utilized. The ''fix'' is obtained by placing a sonar beacon, with self contained batteries, on the ocean floor at a selected site. The vessel is provided with 4 hydrophones installed in the hull at the 4 corners of a square. The sonar beacon radiates sound waves at a fixed pulse rate. If the vessel is directly over the beacon, the sound waves will arrive at all hydrophones simultaneously. A difference in time of arrival indicates the vessel is off location. The sound signals received by the hydrophones are fed into a computer. They are changed into coordinate information, which serves as the primary function of determining corrective action by the vessel's propulsion and thruster system. The computer feeds back information into a control system, which enables the propulsion and thrusters to automatically respond, in order to keep the vessel on the predetermined location. The major drilling components are listed. The deep-sea drilling project is described. A summary of the first leg is given in tabular form.

  12. Scrapheap Challenge

    CERN Document Server

    2004-01-01

    Three British guys at CERN recently took a break from work to try their hand at Scrapheap Challenge. Shown on Channel 4 in the UK, it is a show where two teams must construct a machine for a specific task using only the junk they can scavenge from the scrap yard around them. And they have just 10 hours to build their contraption before it is put to the test. The first round, aired 19 September, pitted a team of three women, from the British Army's Royal Electrical and Mechanical Engineers, against the CERN guys - the Up 'n Atoms: Ali Day, David McFarlane and James Ridewood. Each team, with the help of an appointed expert, had the task of making a giant, 3-metre self-propelled "bowling ball", to roll down a 50 metre bowling alley at skittles 4 metres high. The Up 'n Atoms' contraption featured a small car with a huge wheel on its back. Once up to speed, slamming on the brakes caused the wheel to roll over and take the car with it. On their very last run they managed to take out seven pins. Luckily, though, ...

  13. Calculus problems

    CERN Document Server

    Baronti, Marco; van der Putten, Robertus; Venturi, Irene

    2016-01-01

    This book, intended as a practical working guide for students in Engineering, Mathematics, Physics, or any other field where rigorous calculus is needed, includes 450 exercises. Each chapter starts with a summary of the main definitions and results, which is followed by a selection of solved exercises accompanied by brief, illustrative comments. A selection of problems with indicated solutions rounds out each chapter. A final chapter explores problems that are not designed with a single issue in mind but instead call for the combination of a variety of techniques, rounding out the book’s coverage. Though the book’s primary focus is on functions of one real variable, basic ordinary differential equations (separation of variables, linear first order and constant coefficients ODEs) are also discussed. The material is taken from actual written tests that have been delivered at the Engineering School of the University of Genoa. Literally thousands of students have worked on these problems, ensuring their real-...

  14. Seven challenges for neuroscience.

    Science.gov (United States)

    Markram, Henry

    2013-01-01

    Although twenty-first century neuroscience is a major scientific enterprise, advances in basic research have not yet translated into benefits for society. In this paper, I outline seven fundamental challenges that need to be overcome. First, neuroscience has to become "big science" - we need big teams with the resources and competences to tackle the big problems. Second, we need to create interlinked sets of data providing a complete picture of single areas of the brain at their different levels of organization with "rungs" linking the descriptions for humans and other species. Such "data ladders" will help us to meet the third challenge - the development of efficient predictive tools, enabling us to drastically increase the information we can extract from expensive experiments. The fourth challenge goes one step further: we have to develop novel hardware and software sufficiently powerful to simulate the brain. In the future, supercomputer-based brain simulation will enable us to make in silico manipulations and recordings, which are currently completely impossible in the lab. The fifth and sixth challenges are translational. On the one hand we need to develop new ways of classifying and simulating brain disease, leading to better diagnosis and more effective drug discovery. On the other, we have to exploit our knowledge to build new brain-inspired technologies, with potentially huge benefits for industry and for society. This leads to the seventh challenge. Neuroscience can indeed deliver huge benefits but we have to be aware of widespread social concern about our work. We need to recognize the fears that exist, lay them to rest, and actively build public support for neuroscience research. We have to set goals for ourselves that the public can recognize and share. And then we have to deliver on our promises. Only in this way, will we receive the support and funding we need.

  15. On the metal-rich surfaces of (16) Psyche and other M-type asteroids from interferometric observations in the thermal infrared

    Science.gov (United States)

    Delbo, Marco; Matter, A.; Gundlach, B.; Blum, J.

    2013-10-01

    Asteroids belonging to the spectroscopic M-type exhibit a quasi featureless and moderately red reflectance spectrum and a geometric visible albedo between 0.1 and 0.3. These asteroids were initially thought to be metallic cores of differentiated asteroids that were exposed to space by a catastrophic disruption by impacts. Later, this view has been challenged by the detection of silicates and hydration spectroscopic bands on these bodies. Unveiling the physical properties of the surfaces of these asteroids, and identifying their meteorite analogs is a challenge from remote-sensing observations. Nevertheless, these are crucial problems, important for estimating the number of asteroids that underwent differentiation in the early phases of the formation of our solar system. The thermal inertia is a sensitive indicator for the presence of metal in the regolith on the surfaces of asteroids. We developed a new thermophysical model that allow us to derive the value of the thermal inertia from interferometric observations in the thermal infrared. We report on our investigation of the thermal inertia of M-type asteroids, including the asteroids (16) Psyche, for which we obtained a thermal inertia value anomalously high compared to the thermal inertia values of other asteroids in the same size range. From the thermal inertia and model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles) the regolith grain size is derived.

  16. 'Challenges ahead'

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, S [International Atomic Energy Agency, Vienna (Austria)

    1977-08-15

    Taking into account both technological development and energy resources, one might distinguish four different categories of states, each with very specific concerns: (1) Countries which are both advanced in development and rich in energy resources; (2) Countries which are advanced in development, but poor in energy resources; (3) Countries lacking in technological development, but rich in natural resources which can at present afford to buy both the technology and the know-how, but cannot be expected to remain dependent on foreign expertise and manpower in the long run; and (4) Countries which need assistance both in development and in energy. The IAEA should help to determine the particular set of problems inherent in each group of countries in respect of the use and further development of nuclear technology and, whenever possible, assist in finding appropriate solutions. The first category of IAEA Member States is the one most involved in vast research and development efforts - such as exploring other advanced reactor systems - nuclear fusion, the possibilities of nuclear energy parks with combined production of electricity and heat. States included in the first two categories are specifically interested in problems concerning the back end of the nuclear fuel cycle. In this regard, the Agency has already taken some indicative steps; the study of regional nuclear fuel cycle centres is one of these and its future scope could include, for example, providing advice and developing guidelines for long-term storage of spent fuel in relation to an open-ended fuel cycle. It could also be expanded to studying fuel cycles. A plutonium management study has already been initiated. The technologies now available for the safe treatment and storage of radioactive wastes need practical demonstrations. More attention must also be paid to the eventual decommissioning of nuclear facilities, preferably at the time of planning and siting a nuclear plant. Countries in the third

  17. 'Challenges ahead'

    International Nuclear Information System (INIS)

    Eklund, S.

    1977-01-01

    Taking into account both technological development and energy resources, one might distinguish four different categories of states, each with very specific concerns: (1) Countries which are both advanced in development and rich in energy resources; (2) Countries which are advanced in development, but poor in energy resources; (3) Countries lacking in technological development, but rich in natural resources which can at present afford to buy both the technology and the know-how, but cannot be expected to remain dependent on foreign expertise and manpower in the long run; and (4) Countries which need assistance both in development and in energy. The IAEA should help to determine the particular set of problems inherent in each group of countries in respect of the use and further development of nuclear technology and, whenever possible, assist in finding appropriate solutions. The first category of IAEA Member States is the one most involved in vast research and development efforts - such as exploring other advanced reactor systems - nuclear fusion, the possibilities of nuclear energy parks with combined production of electricity and heat. States included in the first two categories are specifically interested in problems concerning the back end of the nuclear fuel cycle. In this regard, the Agency has already taken some indicative steps; the study of regional nuclear fuel cycle centres is one of these and its future scope could include, for example, providing advice and developing guidelines for long-term storage of spent fuel in relation to an open-ended fuel cycle. It could also be expanded to studying fuel cycles. A plutonium management study has already been initiated. The technologies now available for the safe treatment and storage of radioactive wastes need practical demonstrations. More attention must also be paid to the eventual decommissioning of nuclear facilities, preferably at the time of planning and siting a nuclear plant. Countries in the third

  18. Proceedings of the INAC 2007 International nuclear atlantic conference. Nuclear energy and energetic challenges for 21st. century. 15. Brazilian national meeting on reactor physics and thermal hydraulics; 8. Brazilian national meeting on nuclear applications

    International Nuclear Information System (INIS)

    2007-01-01

    Following the success of INAC 2002 and 2005, INAC 2007 has been held with the 15th Meeting on Reactor Physics and Thermal Hydraulics (XV ENFIR) and the 8th Meeting on Nuclear Applications (VIII ENAN). A key goal of these joint meetings is to bring together scientists to exchange the latest research and development (R and D) information in nuclear science and technology. In the INAC 2007 technical program, plenary sessions, such as round table discussions and keynote lectures, has held to present to the general public the recent advances of peaceful nuclear energy usage, reducing the global warming. Besides, INAC 2007 has offered a poster technical session on Management Systems for Nuclear Organizations. The XV ENFIR has covered all aspects of interdisciplinary R and D related to nuclear reactors, and the VIII ENAN has offered a forum for discussion on nuclear applications in industry, geology, agriculture, medicine, biology, environmental sciences always highlighting the social, economical and environmental improvements generated by nuclear techniques. Both ENFIR and ENAN have also organized oral and poster technical sessions

  19. Proceedings of the INAC 2007 International nuclear atlantic conference. Nuclear energy and energetic challenges for 21st. century. 15. Brazilian national meeting on reactor physics and thermal hydraulics; 8. Brazilian national meeting on nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Following the success of INAC 2002 and 2005, INAC 2007 has been held with the 15th Meeting on Reactor Physics and Thermal Hydraulics (XV ENFIR) and the 8th Meeting on Nuclear Applications (VIII ENAN). A key goal of these joint meetings is to bring together scientists to exchange the latest research and development (R and D) information in nuclear science and technology. In the INAC 2007 technical program, plenary sessions, such as round table discussions and keynote lectures, has held to present to the general public the recent advances of peaceful nuclear energy usage, reducing the global warming. Besides, INAC 2007 has offered a poster technical session on Management Systems for Nuclear Organizations. The XV ENFIR has covered all aspects of interdisciplinary R and D related to nuclear reactors, and the VIII ENAN has offered a forum for discussion on nuclear applications in industry, geology, agriculture, medicine, biology, environmental sciences always highlighting the social, economical and environmental improvements generated by nuclear techniques. Both ENFIR and ENAN have also organized oral and poster technical sessions.

  20. Thyroid Problems

    Science.gov (United States)

    ... Home › Aging & Health A to Z › Thyroid Problems Font size A A A Print Share Glossary Basic ... enough thyroid hormone, usually of the thyroxine (T4) type of hormone. Your T4 levels can drop temporarily ...

  1. Balance Problems

    Science.gov (United States)

    ... fully trust your sense of balance. Loss of balance also raises the risk of falls. This is a serious and even life-threatening ... 65. Balance disorders are serious because of the risk of falls. But occasionally balance problems may warn of another health condition, such ...

  2. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. The applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous`s empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing. 6 refs., 8 figs. (Author)

  3. Thermal fluid mixing behavior during medium break LOCA in evaluation of pressurized thermal shock

    International Nuclear Information System (INIS)

    Jung, Jae Won; Bang, Young Seok; Seul, Kwang Won; Kim, Hho Jung

    1998-01-01

    Thermal fluid mixing behavior during a postulated medium-size hot leg break loss of coolant accident is analyzed for the international comparative assessment study on pressurized thermal shock (PTS-ICAS) proposed by OECD-NEA. the applicability of RELAP5 code to analyze the thermal fluid mixing behavior is evaluated through a simple modeling relevant to the problem constraints. Based on the calculation result, the onset of thermal stratification is investigated using Theofanous's empirical correlation. Sensitivity calculations using a fine node model and crossflow model are also performed to evaluate the modeling capability on multi-dimensional characteristics related to thermal fluid mixing

  4. Thermal neutron actinide data

    International Nuclear Information System (INIS)

    Tellier, H.

    1992-01-01

    During the 70's, the physicists involved in the cross section measurements for the low energy neutrons were almost exclusively interested in the resonance energy range. The thermal range was considered as sufficiently known. In the beginning of the 80's, reactor physicists had again to deal with the delicate problem of the power reactor temperature coefficient, essentially for the light water reactors. The measured value of the reactivity temperature coefficient does not agree with the computed one. The later is too negative. For obvious safety reasons, it is an important problem which must be solved. Several causes were suggested to explain this discrepancy. Among all these causes, the spectral shift in the thermal energy range seems to be very important. Sensibility calculations shown that this spectral shift is very sensitive to the shape of the neutron cross sections of the actinides for energies below one electron-volt. Consequently, reactor physicists require new and accurate measurements in the thermal and subthermal energy ranges. A part of these new measurement results were recently released and reviewed. The purpose of this study is to complete the preceding review with the new informations which are now available. In reactor physics the major actinides are the fertile nuclei, uranium 238, thorium 232 and plutonium 240 and the fissile nuclei, uranium 233, uranium 235 and plutonium 239. For the fertile nuclei the main datum is the capture cross section, for the fissile nuclei the data of interest are nu-bar, the fission and capture cross sections or a combination of these data such as η or α. In the following sections, we will review the neutron data of the major actinides for the energy below 1 eV

  5. Advances in Thermal Insulation. Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Thorsell, Thomas

    2012-07-01

    We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60 % if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hydrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The

  6. Transport of thermal water from well to thermal baths

    Science.gov (United States)

    Montegrossi, Giordano; Vaselli, Orlando; Tassi, Franco; Nocentini, Matteo; Liccioli, Caterina; Nisi, Barbara

    2013-04-01

    The main problem in building a thermal bath is having a hot spring or a thermal well located in an appropriate position for customer access; since Roman age, thermal baths were distributed in the whole empire and often road and cities were built all around afterwards. Nowadays, the perspectives are changed and occasionally the thermal resource is required to be transported with a pipeline system from the main source to the spa. Nevertheless, the geothermal fluid may show problems of corrosion and scaling during transport. In the Ambra valley, central Italy, a geothermal well has recently been drilled and it discharges a Ca(Mg)-SO4, CO2-rich water at the temperature of 41 °C, that could be used for supplying a new spa in the surrounding areas of the well itself. The main problem is that the producing well is located in a forest tree ca. 4 km far away from the nearest structure suitable to host the thermal bath. In this study, we illustrate the pipeline design from the producing well to the spa, constraining the physical and geochemical parameters to reduce scaling and corrosion phenomena. The starting point is the thermal well that has a flow rate ranging from 22 up to 25 L/sec. The thermal fluid is heavily precipitating calcite (50-100 ton/month) due to the calcite-CO2 equilibrium in the reservoir, where a partial pressure of 11 bar of CO2 is present. One of the most vexing problems in investigating scaling processed during the fluid transport in the pipeline is that there is not a proper software package for multiphase fluid flow in pipes characterized by such a complex chemistry. As a consequence, we used a modified TOUGHREACT with Pitzer database, arranged to use Darcy-Weisbach equation, and applying "fictitious" material properties in order to give the proper y- z- velocity profile in comparison to the analytical solution for laminar fluid flow in pipes. This investigation gave as a result the lowest CO2 partial pressure to be kept in the pipeline (nearly 2

  7. 浅谈火电厂稳高压消防给水系统的若干问题%Existing problems of stabilized high pressure fire fighting water supply system in thermal power plant

    Institute of Scientific and Technical Information of China (English)

    赵佰波; 王欣

    2012-01-01

    The definitions of stabilized high pressure fire fighting water supply system and temporary high pressure fire fighting water supply system were introduced, and a comparison between the two systems was carried out. Some suggestions for the setup of pump adapters and fire water tanks of stabilized high pressure fire fighting water supply system in thermal power plant were pointed out.%介绍了稳高压消防给水系统与临时高压消防给水系统的定义,进行了两类消防给水系统的对比,对火电厂稳高压消防给水系统水泵接合器及消防水箱的设置提出建议.

  8. Challenges faced by NRCs

    International Nuclear Information System (INIS)

    Longoria, L.C.

    2001-01-01

    The Mexican Nuclear Research Institute (ININ) played an important role in setting up of nuclear power plants (two) and development of fuel technology. However, with no current plans for expansion of this programme, the Institute is looking mainly into multi-cycle fuel management and life extension issues. The Institute focuses on programmes related to radioisotope and radiation applications and on the use of nuclear technologies for non-nuclear applications. The ININ is the major provider of radioisotopes for medical uses. It also promotes and uses nuclear analytical techniques for addressing a variety of problems. In non-nuclear areas some R and D examples include: the use of thermal plasma for hazardous waste incineration, biodegradation of polymers and development of separation techniques for treating industrial effluents. For preservation of knowledge, the Institute has instituted PhD. programmes in materials science, medical physics and nuclear science in collaboration with a university. (author)

  9. Theoretical Modelling Methods for Thermal Management of Batteries

    Directory of Open Access Journals (Sweden)

    Bahman Shabani

    2015-09-01

    Full Text Available The main challenge associated with renewable energy generation is the intermittency of the renewable source of power. Because of this, back-up generation sources fuelled by fossil fuels are required. In stationary applications whether it is a back-up diesel generator or connection to the grid, these systems are yet to be truly emissions-free. One solution to the problem is the utilisation of electrochemical energy storage systems (ESS to store the excess renewable energy and then reusing this energy when the renewable energy source is insufficient to meet the demand. The performance of an ESS amongst other things is affected by the design, materials used and the operating temperature of the system. The operating temperature is critical since operating an ESS at low ambient temperatures affects its capacity and charge acceptance while operating the ESS at high ambient temperatures affects its lifetime and suggests safety risks. Safety risks are magnified in renewable energy storage applications given the scale of the ESS required to meet the energy demand. This necessity has propelled significant effort to model the thermal behaviour of ESS. Understanding and modelling the thermal behaviour of these systems is a crucial consideration before designing an efficient thermal management system that would operate safely and extend the lifetime of the ESS. This is vital in order to eliminate intermittency and add value to renewable sources of power. This paper concentrates on reviewing theoretical approaches used to simulate the operating temperatures of ESS and the subsequent endeavours of modelling thermal management systems for these systems. The intent of this review is to present some of the different methods of modelling the thermal behaviour of ESS highlighting the advantages and disadvantages of each approach.

  10. A Water-Service Challenge

    Science.gov (United States)

    Roman, Harry T.

    2011-01-01

    It is important to let students see the value of mathematics in design--and how mathematics lends perspective to problem solving. In this article, the author describes a water-service challenge which enables students to design a water utility system that uses surface runoff into an open reservoir as the potable water source. This challenge…

  11. Thermal processing systems for TRU mixed waste

    International Nuclear Information System (INIS)

    Eddy, T.L.; Raivo, B.D.; Anderson, G.L.

    1992-01-01

    This paper presents preliminary ex situ thermal processing system concepts and related processing considerations for remediation of transuranic (TRU)-contaminated wastes (TRUW) buried at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Anticipated waste stream components and problems are considered. Thermal processing conditions required to obtain a high-integrity, low-leachability glass/ceramic final waste form are considered. Five practical thermal process system designs are compared. Thermal processing of mixed waste and soils with essentially no presorting and using incineration followed by high temperature melting is recommended. Applied research and development necessary for demonstration is also recommended

  12. Solar thermal utilization--an overview

    International Nuclear Information System (INIS)

    Chen Deming; Xu Gang

    2007-01-01

    Solar energy is an ideal renewable energy source and its thermal utilization is one of its most important applications. We review the status of solar thermal utilization, including: (1) developed technologies which are already widely used all over the world, such as solar assisted water heaters, solar cookers, solar heated buildings and so on; (2) advanced technologies which are still in the development or laboratory stage and could have more innovative applications, including thermal power generation, refrigeration, hydrogen production, desalination, and chimneys; (3) major problems which need to be resolved for advanced utilizaiton of solar thermal energy. (authors)

  13. Spent fuel transportation problems

    International Nuclear Information System (INIS)

    Kondrat'ev, A.N.; Kosarev, Yu.A.; Yulikov, E.A.

    1977-01-01

    In this paper, problems of transportation of nuclear spent fuel to reprocessing plants are discussed. The solutions proposed are directed toward the achievement of the transportation as economic and safe as possible. The increase of the nuclear power plants number in the USSR and the great distances between these plants and the reprocessing plants involve an intensification of the spent fuel transportation. Higher burnup and holdup time reduction cause the necessity of more bulky casks. In this connection, the economic problems become still more important. One of the ways of the problem solution is the development of rational and cheap cask designs. Also, the enforcement in the world of the environmental and personnel health protection requires to increase the transportation reliability and safety. The paper summarizes safe transportation rules with clarifying the following questions: the increase of the transport unit quantity of the spent fuel; rational shipment organization that minimizes vehicle turnover cycle duration; development of the reliable calculation methods to determine strength, thermal conditions and nuclear safety of transport packaging as applied to the vehicles of high capacity; maximum unification of vehicles, calculation methods and documents; and cask testing on models and in pilot scale on specific test rigs to assure that they meet the international safe fuel shipment rules. Besides, some considerations on the choice and use of structural materials for casks are given, and problems of manufacturing such casks from uranium and lead are considered, as well as problems of the development of fireproof shells, control instrumentation, vehicles decontamination, etc. All the problems are considered from the point of view of normal and accidental shipment conditions. Conclusions are presented [ru

  14. Complementarity problems

    CERN Document Server

    Isac, George

    1992-01-01

    The study of complementarity problems is now an interesting mathematical subject with many applications in optimization, game theory, stochastic optimal control, engineering, economics etc. This subject has deep relations with important domains of fundamental mathematics such as fixed point theory, ordered spaces, nonlinear analysis, topological degree, the study of variational inequalities and also with mathematical modeling and numerical analysis. Researchers and graduate students interested in mathematical modeling or nonlinear analysis will find here interesting and fascinating results.

  15. Agricultural problems

    International Nuclear Information System (INIS)

    Bickerton, George E.

    1997-01-01

    Although there were not reasons to deplore against major activity release from any of the 110 industrial reactors authorized to operate in US, the nuclear incident that occurred at the Three Mile Island Plant in 1979 urged the public conscience toward the necessity of readiness to cope with events of this type. The personnel of the Emergency Planning Office functioning in the frame of US Department of Agriculture has already participated in around 600 intervention drillings on a federal, local or state scale to plan, test or asses radiological emergency plans or to intervene locally. These exercises allowed acquiring a significant experience in elaborating emergency plans, planning the drillings, working out scenarios and evaluation of the potential impact of accidents from the agricultural point of view. We have also taken part in different international drillings among which the most recent are INEX 1 and RADEX 94. We have found on these occasions that the agricultural problems are essential preoccupations in most of the cases no matter if the context is international, national, local or of state level. The paper poses problems specifically related to milk, fruits and vegetables, soils, meat and meat products. Finally the paper discusses issues like drilling planning, alarm and notification, sampling strategy, access authorizations for farmers, removing of contamination wastes. A number of social, political and economical relating problems are also mentioned

  16. Open problems in string cosmology

    International Nuclear Information System (INIS)

    Toumbas, N.

    2010-01-01

    Some of the open problems in string cosmology are highlighted within the context of the recently constructed thermal and quantum superstring cosmological solutions. Emphasis is given on the high temperature cosmological regime, where it is argued that thermal string vacua in the presence of gravito-magnetic fluxes can be used to bypass the Hagedorn instabilities of string gas cosmology. This article is based on a talk given at the workshop on ''Cosmology and Strings'', Corfu, September 6-13, 2009. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  17. Wide-range measurement of thermal effusivity using molybdenum thin film with low thermal conductivity for thermal microscopes

    Science.gov (United States)

    Miyake, Shugo; Matsui, Genzou; Ohta, Hiromichi; Hatori, Kimihito; Taguchi, Kohei; Yamamoto, Suguru

    2017-07-01

    Thermal microscopes are a useful technology to investigate the spatial distribution of the thermal transport properties of various materials. However, for high thermal effusivity materials, the estimated values of thermophysical parameters based on the conventional 1D heat flow model are known to be higher than the values of materials in the literature. Here, we present a new procedure to solve the problem which calculates the theoretical temperature response with the 3D heat flow and measures reference materials which involve known values of thermal effusivity and heat capacity. In general, a complicated numerical iterative method and many thermophysical parameters are required for the calculation in the 3D heat flow model. Here, we devised a simple procedure by using a molybdenum (Mo) thin film with low thermal conductivity on the sample surface, enabling us to measure over a wide thermal effusivity range for various materials.

  18. The Elder Problem

    Directory of Open Access Journals (Sweden)

    John W. Elder

    2017-03-01

    Full Text Available This paper presents an autobiographical and biographical historical account of the genesis, evolution and resolution of the Elder Problem. It begins with John W. Elder and his autobiographical story leading to his groundbreaking work on natural convection at Cambridge in the 1960’s. His seminal work published in the Journal of Fluid Mechanics in 1967 became the basis for the modern benchmark of variable density flow simulators that we know today as “The Elder Problem”. There have been well known and major challenges with the Elder Problem model benchmark—notably the multiple solutions that were ultimately uncovered using different numerical models. Most recently, it has been shown that the multiple solutions are indeed physically realistic bifurcation solutions to the Elder Problem and not numerically spurious artefacts. The quandary of the Elder Problem has now been solved—a major scientific breakthrough for fluid mechanics and for numerical modelling. This paper—records, reflections, reminiscences, stories and anecdotes—is an historical autobiographical and biographical memoir. It is the personal story of the Elder Problem told by some of the key scientists who established and solved the Elder Problem. 2017 marks the 50 year anniversary of the classical work by John W. Elder published in Journal of Fluid Mechanics in 1967. This set the stage for this scientific story over some five decades. This paper is a celebration and commemoration of the life and times of John W. Elder, the problem named in his honour, and some of the key scientists who worked on, and ultimately solved, it.

  19. Review on mathematical basis for thermal conduction equation

    Energy Technology Data Exchange (ETDEWEB)

    Park, D. G.; Kim, H. M

    2007-10-15

    In the view point of thermal conductivity measurement technology, It is very useful to understand mathematical theory of thermal conduction equation in order to evaluation of measurement data and to solve diverse technical problem in measurement. To approach this mathematical theory, thermal conduction equation is derived by Fourier thermal conduction law. Since thermal conduction equation depends on the Lapacian operator basically, mathematical meaning of Lapalacian and various diffusion equation including Laplacian have been studied. Stum-Liouville problem and Bessel function were studied in this report to understand analytical solution of various diffusion equation.

  20. Review on mathematical basis for thermal conduction equation

    International Nuclear Information System (INIS)

    Park, D. G.; Kim, H. M.

    2007-10-01

    In the view point of thermal conductivity measurement technology, It is very useful to understand mathematical theory of thermal conduction equation in order to evaluation of measurement data and to solve diverse technical problem in measurement. To approach this mathematical theory, thermal conduction equation is derived by Fourier thermal conduction law. Since thermal conduction equation depends on the Lapacian operator basically, mathematical meaning of Lapalacian and various diffusion equation including Laplacian have been studied. Stum-Liouville problem and Bessel function were studied in this report to understand analytical solution of various diffusion equation