WorldWideScience

Sample records for current models propose

  1. Social Security reform: evaluating current proposals. Latest results of the EBRI-SSASIM2 policy simulation model.

    Science.gov (United States)

    Copeland, C; VanDerhei, J; Salisbury, D L

    1999-06-01

    The present Social Security program has been shown to be financially unsustainable in the future without modification to the current program. The purpose of this Issue Brief, EBRI's fourth in a series on Social Security reform, is threefold: to illustrate new features of the EBRI-SSASIM2 policy simulation model not available in earlier EBRI publications, to expand quantitative analysis to specific proposals, and to evaluate the uncertainty involved in proposals that rely on equity investment. This analysis compares the Gregg/Breaux-Kolbe/Stenholm (GB-KS) and Moynihan/Kerrey proposals with three generic or "traditional" reforms: increasing taxes, reducing benefits, and/or increasing the retirement age. Both proposals would create individual accounts by "carving out" funds from current Social Security payroll taxes. This analysis also examines other proposed changes that would "add on" to existing Social Security funds through the use of general revenue transfers and/or investment in the equities market. President Clinton has proposed a general revenue transfer and the collective investment of some of the OASDI trust fund assets in equities. Reps. Archer and Shaw have proposed a general revenue tax credit to establish individual accounts that would be invested partially in the equities markets. When comparing Social Security reform proposals that would specifically alter benefit levels, the Moynihan/Kerrey bill compares quite favorably with the other proposals in both benefit levels and payback ratios, when individuals elect to use the individual account option. In contrast, the GB-KS bills do not compare quite as favorably for their benefit levels, but do compare favorably in terms of payback ratios. An important comparison in these bills is the administrative costs of managing the individual accounts, since benefits can be lowered by up to 23 percent when going from the assumed low to high administrative costs. Moreover, allowing individuals to decide whether to

  2. Proposed reliability cost model

    Science.gov (United States)

    Delionback, L. M.

    1973-01-01

    The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

  3. A three-phase model proposal for the evolution of scientific communication: from first print periodicals to current electronic communication system

    Directory of Open Access Journals (Sweden)

    Patrícia Bertin

    Full Text Available Scientific communication has undergone deep transformations, since the emergence of Internet. Aiming to provide further thought on the evolution of scientific communication, this paper features a historical overview of the scientific communication advances over the last twenty years through a three-phase model for the evolution of the electronic journal and the preprints services, and presents Brazilian contemporary panorama for scientific communication. The three-phase model presented in this work is an adaptation of that one proposed by Tenopir et al. (2003 to describe the patterns of journal use by scientists since 1990. The early evolutionary phase followed the emergence of the first digital journals and the creation of repositories in the Web for publishing preliminary versions of scientific literature on the author’s initiative; by that time, most academics reproved electronic publishing initiatives. From 1996 and forward, in the consolidation phase, electronic journals were commonly identical to their print counterparts; the acceptance of the electronic format began to increase, and preprint services got underway in several disciplines. The advanced evolutionary phase started with the world discussion on open access to scientific information. The comparison of the current electronic journal with that viewed by enthusiasts in the first years of the 1990s shows that some aspects still remain to be improved in electronic formal and informal communication, towards effective dissemination of scientific information.

  4. Primary Radiation Damage in Materials. Review of Current Understanding and Proposed New Standard Displacement Damage Model to Incorporate in Cascade Defect Production Efficiency and Mixing Effects

    International Nuclear Information System (INIS)

    Nordlund, Kai; Sand, Andrea E.; Granberg, Fredric; Zinkle, Steven J.; Stoller, Roger; Averback, Robert S.; Suzudo, Tomoaki; Malerba, Lorenzo; Banhart, Florian; Weber, William J.; Willaime, Francois; Dudarev, Sergei; Simeone, David

    2015-01-01

    Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Multi-scale Modelling of Fuels and Structural Materials for Nuclear Systems (WPMM) was established in 2008 to assess the scientific and engineering aspects of fuels and structural materials, aiming at evaluating multi-scale models and simulations as validated predictive tools for the design of nuclear systems, fuel fabrication and performance. The WPMM's objective is to promote the exchange of information on models and simulations of nuclear materials, theoretical and computational methods, experimental validation, and related topics. It also provides member countries with up-to-date information, shared data, models and expertise. The WPMM Expert Group on Primary Radiation Damage (PRD) was established in 2009 to determine the limitations of the NRT-dpa standard, in the light of both atomistic simulations and known experimental discrepancies, to revisit the NRT-dpa standard and to examine the possibility of proposing a new improved standard of primary damage characteristics. This report reviews the current understanding of primary radiation damage from neutrons, ions and electrons (excluding photons, atomic clusters and more exotic particles), with emphasis on the range of validity of the 'displacement per atom' (dpa) concept in all major classes of materials with the exception of organics. The report also introduces an 'athermal recombination-corrected dpa' (arc-dpa) relation that uses a relatively simple functional to address the well-known issue that 'displacement per atom' (dpa) overestimates damage production in metals under energetic displacement cascade conditions, as well as a 'replacements-per-atom' (rpa) equation, also using a relatively simple functional, that accounts for the fact that dpa is understood to severely underestimate actual atom relocation (ion beam mixing) in metals. (authors)

  5. Monju: Current status and proposed improvements

    International Nuclear Information System (INIS)

    Nagata, Takashi

    2001-01-01

    Activities since the Monju reactor accident are described. They include investigation of sodium leak, namely cause of thermocouple well failure and damage caused by sodium combustion. This accident did not affect the safety of the reactor or the integrity of the buildings and structures. Improvements have been proposed to overcome the problems highlighted by the comprehensive safety review of Monju. Improvements of communication are discussed, including incident reporting, public information, corporate culture. The proposed countermeasures against sodium leakage are described in detail. They are as follows: prevention of sodium leakage, early detection of sodium leakage, reduction of sodium spilling and prevention of re-ignition, suppression of moisture release from concrete structures. Replacement of thermocouple wells is proposed, as well as methods of preventing flow induced vibration

  6. Nuclear regulations: current status and proposed initiatives

    International Nuclear Information System (INIS)

    Domondon, D.B.; Valdezco, E.M.; Mateo, A.J.; Parami, V.K.

    1996-01-01

    The science Act of 1958 created the Philippine Atomic Energy Commission, presently known as the Philippine Nuclear Research Institute (PNRI), under the Department of Science and Technology (DOST). The PNRI is tasked with the dual role of promotion and control of the peaceful applications of atomic energy. To carry its mandate of regulation and control on the use of raioisotopes in various fields, the PNRI had promulgated and issued specific regulations known as the Code of PNRI regulations. This paper summarizes the activities undertaken by PNRI in the continuing process of review and subsequent revisions of the Code of PNRI regulations and related guidance documents. It highlights proposed modifications in the present regulations in an attempt to adopt the new international basic safety standards, the practical problems and related issues attendant to the implementation of these new standards, among others. In line with the overall objective of PNRI to ensure the safe application of nuclear energy and radiation technology in various fields, the institute conducted a series of regulatory information conferences to provide an opportunity for members of the regulatory staff of the PNRI and licenses to discuss safety initiatives and regulatory issues. This paper will also provide an in-depth assessment of the lessons learned from these conferences which were conducted by sector or by specific applications for a more focused approach, e.g. radiopharmaceuticals, industrial radiography, research, among others. Licensees' feedback on the PNRI regulatory process are presented as part of the overall objective of enhancing the operational experiences of the licensing, review and evaluation group as well as that of inspection, enforcement and compliance. Several proposed initiatives for consideration of the PNRI to further strengthen its regulatory functions are also briefly outlined. (author)

  7. Proposed Reliability/Cost Model

    Science.gov (United States)

    Delionback, L. M.

    1982-01-01

    New technique estimates cost of improvement in reliability for complex system. Model format/approach is dependent upon use of subsystem cost-estimating relationships (CER's) in devising cost-effective policy. Proposed methodology should have application in broad range of engineering management decisions.

  8. The 'model omnitron' proposed experiment

    International Nuclear Information System (INIS)

    Sestero, A.

    1997-05-01

    The Model Omitron is a compact tokamak experiment which is designed by the Fusion Engineering Unit of ENEA and CITIF CONSORTIUM. The building of Model Omitron would allow for full testing of Omitron engineering, and partial testing of Omitron physics -at about 1/20 of the cost that has been estimated for the larger parent machine. In particular, due to the unusually large ohmic power densities (up to 100 times the nominal value in the Frascati FTU experiment), in Model Omitron the radial energy flux is reaching values comparable or higher than envisaged of the larger ignition experiments Omitron, Ignitor and Iter. Consequently, conditions are expected to occur at the plasma border in the scrape-off layer of Model Omitron, which are representative of the quoted larger experiments. Moreover, since all this will occur under ohmic heating alone, one will hopefully be able to derive an energy transport model fo the ohmic heating regime that is valid over a range of plasma parameters (in particular, of the temperature parameter) wider than it was possible before. In the Model Omitron experiment, finally - by reducing the plasma current and/or the toroidal field down to, say, 1/3 or 1/4 of the nominal values -additional topics can be tackled, such as: large safety-factor configurations (of interest for improving confinement), large aspect-ratio configurations (of interest for the investigation of advanced concepts in tokamaks), high beta (with RF heating -also of interest for the investigation of advanced concepts in tokamaks), long pulse discharges (of interest for demonstrating stationary conditions in the current profile)

  9. Numerical modeling of transformer inrush currents

    Energy Technology Data Exchange (ETDEWEB)

    Cardelli, E. [Department of Industrial Engineering, University of Perugia, I-06125 Perugia (Italy); Center for Electric and Magnetic Applied Research (Italy); Faba, A., E-mail: faba@unipg.it [Department of Industrial Engineering, University of Perugia, I-06125 Perugia (Italy); Center for Electric and Magnetic Applied Research (Italy)

    2014-02-15

    This paper presents an application of a vector hysteresis model to the prediction of the inrush current due the arbitrary initial excitation of a transformer after a fault. The approach proposed seems promising in order to predict the transient overshoot in current and the optimal time to close the circuit after the fault.

  10. Women's Language Model: A Proposal.

    Science.gov (United States)

    Dumas, Bethany K.

    It is possible to think of women's language in terms of the model implied by the following statement. Insofar as native speakers of English are concerned, the language of women in America has four sets of components: those shared with the language of men in America; those shared, in varying proportions, with other women living in patriarchies;…

  11. On tridimensional rip current modeling

    Science.gov (United States)

    Marchesiello, Patrick; Benshila, Rachid; Almar, Rafael; Uchiyama, Yusuke; McWilliams, James C.; Shchepetkin, Alexander

    2015-12-01

    Do lateral shear instabilities of nearshore circulation account for a substantial part of Very Low-Frequency (VLF) variability? If yes, it would promote stirring and mixing of coastal waters and surf-shelf exchanges. Another question is whether tridimensional transient processes are important for instability generation. An innovative modeling system with tridimensional wave-current interactions was designed to investigate transient nearshore currents and interactions between nearshore and innershelf circulations. We present here some validation of rip current modeling for the Aquitanian coast of France, using in-situ and remote video sensing. We then proceed to show the benefits of 3D versus 2D (depth-mean flow) modeling of rip currents and their low-frequency variability. It appears that a large part of VLF motions is due to intrinsic variability of the tridimensional flow. 3D models may thus provide a valuable, only marginally more expensive alternative to conventional 2D approaches that miss the vertical flow structure and its nonlinear interaction with the depth-averaged flow.

  12. Circulation-based Modeling of Gravity Currents

    Science.gov (United States)

    Meiburg, E. H.; Borden, Z.

    2013-05-01

    Atmospheric and oceanic flows driven by predominantly horizontal density differences, such as sea breezes, thunderstorm outflows, powder snow avalanches, and turbidity currents, are frequently modeled as gravity currents. Efforts to develop simplified models of such currents date back to von Karman (1940), who considered a two-dimensional gravity current in an inviscid, irrotational and infinitely deep ambient. Benjamin (1968) presented an alternative model, focusing on the inviscid, irrotational flow past a gravity current in a finite-depth channel. More recently, Shin et al. (2004) proposed a model for gravity currents generated by partial-depth lock releases, considering a control volume that encompasses both fronts. All of the above models, in addition to the conservation of mass and horizontal momentum, invoke Bernoulli's law along some specific streamline in the flow field, in order to obtain a closed system of equations that can be solved for the front velocity as function of the current height. More recent computational investigations based on the Navier-Stokes equations, on the other hand, reproduce the dynamics of gravity currents based on the conservation of mass and momentum alone. We propose that it should therefore be possible to formulate a fundamental gravity current model without invoking Bernoulli's law. The talk will show that the front velocity of gravity currents can indeed be predicted as a function of their height from mass and momentum considerations alone, by considering the evolution of interfacial vorticity. This approach does not require information on the pressure field and therefore avoids the need for an energy closure argument such as those invoked by the earlier models. Predictions by the new theory are shown to be in close agreement with direct numerical simulation results. References Von Karman, T. 1940 The engineer grapples with nonlinear problems, Bull. Am. Math Soc. 46, 615-683. Benjamin, T.B. 1968 Gravity currents and related

  13. Soft commutated direct current motor [summary of proposed paper

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, John S.

    1998-10-22

    A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.

  14. Microscopic models for bridging electrostatics and currents

    Science.gov (United States)

    Borghi, L.; DeAmbrosis, A.; Mascheretti, P.

    2007-03-01

    A teaching sequence based on the use of microscopic models to link electrostatic phenomena with direct currents is presented. The sequence, devised for high school students, was designed after initial work carried out with student teachers attending a school of specialization for teaching physics at high school, at the University of Pavia. The results obtained with them are briefly presented, because they directed our steps for the development of the teaching sequence. For both the design of the experiments and their interpretation, we drew inspiration from the original works of Alessandro Volta; in addition, a structural model based on the particular role of electrons as elementary charges both in electrostatic phenomena and in currents was proposed. The teaching sequence starts from experiments on charging objects by rubbing and by induction, and engages students in constructing microscopic models to interpret their observations. By using these models and by closely examining the ideas of tension and capacitance, the students acknowledge that a charging (or discharging) process is due to the motion of electrons that, albeit for short time intervals, represent a current. Finally, they are made to see that the same happens in transients of direct current circuits.

  15. Analysis of Current Supplier Relationship Management Practices: A Solution Proposal

    OpenAIRE

    Gomes Campelo Filho, Eulalio

    2009-01-01

    The work contributes with the existing literature by investigating current SRM practices. Based on the research, the author has designed an information system framework, which provides companies with an innovative SRM solution to manage their indirect material purchasing process through an environment that supports companies entire plan-to-order activities, including functionalities such as central data management, spend data management, e-sourcing and the usual e-procurement features.

  16. Proposal for an ecoradiological centre model

    International Nuclear Information System (INIS)

    Perovic, S.M.; Zunic, Z.; Demajo, M.; Konjevic, N.

    1998-01-01

    The problem of establishing an optimal Ecoradiological Centre Model is studied in some detail for the town of Kotor which is under the protection of the World Cultural and Natural Heritage. The proposed structure of the Centre is analyzed from the view of Engineering, Education and Scientific parameters. This Model is suitable for implementation as a network Centre Model for the state of Montenegro. Further, the modelling strategy of the ecoradiological condition control of natural, construction, bio and technological systems is elaborated. The proposal includes the ecoradiological monitoring, radioactive and electromagnetic radiation processing and protection for different natural zones as well as their different geostructures, aerial and hydrogeological conditions. The programme also includes all housing objects (hotels, flats, houses, office premises etc.). Here will also be presented the radiation protection and recommendations for the implementation of Title VII of the European Basic Safety Standards Directive (BSS), concerning significant increase in exposure due to natural radiation sources. Also, the proposal of Local Radiation Protection for the town of Kotor is presented. Our proposal for an Ecoradiological Centre Model presented here is in a form of a pilot programme, applicable also for other towns and states. (author)

  17. A proposal for B-physics on current lattices

    Energy Technology Data Exchange (ETDEWEB)

    Blossier, B. [Paris 11 Univ., 91 - Orsay (France). Lab. de Physique Theorique; Dimopoulos, P.; Frezzotti, R. [Roma Univ., Tor Vergata (Italy). Dipt. di Fisica; INFN, Roma Tor Vergata (IT)] (and others)

    2009-10-15

    A method to extract B-physics parameters (b-quark mass and f{sub B}, f{sub Bs} decay constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing appropriate ratios of heavy-light meson masses and decay constants, respectively, possessing a precisely known static limit, and evaluating them at various pairs of heavy quark masses around the charm. Via a smooth interpolation in the heavy quark mass from the easily accessible charm region to the asymptotic point, B-physics parameters are computed with a few percent (statistical + systematic) error using recently produced N{sub f}=2 maximally twisted Wilson fermions data. (orig.)

  18. A proposed general model of information behaviour.

    Directory of Open Access Journals (Sweden)

    2003-01-01

    Full Text Available Presents a critical description of Wilson's (1996 global model of information behaviour and proposes major modification on the basis of research into information behaviour of managers, conducted in Poland. The theoretical analysis and research results suggest that Wilson's model has certain imperfections, both in its conceptual content, and in graphical presentation. The model, for example, cannot be used to describe managers' information behaviour, since managers basically are not the end users of external from organization or computerized information services, and they acquire information mainly through various intermediaries. Therefore, the model cannot be considered as a general model, applicable to every category of information users. The proposed new model encompasses the main concepts of Wilson's model, such as: person-in-context, three categories of intervening variables (individual, social and environmental, activating mechanisms, cyclic character of information behaviours, and the adoption of a multidisciplinary approach to explain them. However, the new model introduces several changes. They include: 1. identification of 'context' with the intervening variables; 2. immersion of the chain of information behaviour in the 'context', to indicate that the context variables influence behaviour at all stages of the process (identification of needs, looking for information, processing and using it; 3. stress is put on the fact that the activating mechanisms also can occur at all stages of the information acquisition process; 4. introduction of two basic strategies of looking for information: personally and/or using various intermediaries.

  19. A proposed experiment on ball lightning model

    International Nuclear Information System (INIS)

    Ignatovich, Vladimir K.; Ignatovich, Filipp V.

    2011-01-01

    Highlights: → We propose to put a glass sphere inside an excited gas. → Then to put a light ray inside the glass in a whispering gallery mode. → If the light is resonant to gas excitation, it will be amplified at every reflection. → In ms time the light in the glass will be amplified, and will melt the glass. → A liquid shell kept integer by electrostriction forces is the ball lightning model. -- Abstract: We propose an experiment for strong light amplification at multiple total reflections from active gaseous media.

  20. Multinucleon Ejection Model for Two Body Current Neutrino Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk, Jan T.; /Fermilab

    2012-06-01

    A model is proposed to describe nucleons ejected from a nucleus as a result of two-body-current neutrino interactions. The model can be easily implemented in Monte Carlo neutrino event generators. Various possibilities to measure the two-body-current contribution are discussed. The model can help identify genuine charge current quasielastic events and allow for a better determination of the systematic error on neutrino energy reconstruction in neutrino oscillation experiments.

  1. A THICK CURRENT SHELL MODEL

    African Journals Online (AJOL)

    2005-08-25

    Aug 25, 2005 ... control ling the current distribution latitudinally and vertically ... horizontal plane (v 3 constant) as a result oF the ... optimisation subroutine of licensed MATLAB 6.0 ... electrojct axis does not coincide with the dip equator.

  2. Agora: A proposal to overcome the limitations of the current knowledge creation process

    OpenAIRE

    ScientistFive

    2015-01-01

    Agora: A proposal to overcome the limitations of the current knowledge creation process ======================================================================================= By Scientistsfive () Abstract: The knowledge creation process is broken and can be improved by a combination of currently emerging tools. The rationale for this proposal is the notion that the current scientific process is not optimal: * Artificially staged competitions (g...

  3. Electric current model of magnetosphere

    International Nuclear Information System (INIS)

    Alfen, H.

    1979-05-01

    A dualism between the field and the particle approach exists also in plasma physics. A number of phenomena, such as the formation of double layers and the energy transport form one region to another, can be understood only by the particle (electric current) description. Hence a translation of the traditional field description into a particle (electric current) description is essential. Such a translation has earlier been made for the heliosphere. The purpose of this paper is to outline a similar application to the magnetosphere, focussing on the energy transfer from the solar wind. As a first approximation a magnetic field consisting of a dipole field and homogeneous magnetic field is used whereas in a second approximation the configuration is more realistic. (author)

  4. Media Accountability Systems: Models, proposals and outlooks

    Directory of Open Access Journals (Sweden)

    Luiz Martins da Silva

    2007-06-01

    Full Text Available This paper analyzes one of the basic actions of SOS-Imprensa, the mechanism to assure Media Accountability with the goal of proposing a synthesis of models for the Brazilian reality. The article aims to address the possibilities of creating and improving mechanisms to stimulate the democratic press process and to mark out and assure freedom of speech and personal rights with respect to the media. Based on the Press Social Responsibility Theory, the hypothesis is that the experiences analyzed (Communication Council, Press Council, Ombudsman and Readers Council are alternatives for accountability, mediation and arbitration, seeking visibility, trust and public support in favor of fairer media.

  5. A Proposed Conceptual Model of Military Medical Readiness

    National Research Council Canada - National Science Library

    Van Hall, Brian M

    2007-01-01

    .... The basis for the proposed conceptual model builds on common and accepted latent variable and theoretical modeling techniques proposed by healthcare scholars, organizational theorists, mathematical...

  6. Air Emissions Damages from Municipal Drinking Water Treatment Under Current and Proposed Regulatory Standards.

    Science.gov (United States)

    Gingerich, Daniel B; Mauter, Meagan S

    2017-09-19

    Water treatment processes present intersectoral and cross-media risk trade-offs that are not presently considered in Safe Drinking Water Act regulatory analyses. This paper develops a method for assessing the air emission implications of common municipal water treatment processes used to comply with recently promulgated and proposed regulatory standards, including concentration limits for, lead and copper, disinfection byproducts, chromium(VI), strontium, and PFOA/PFOS. Life-cycle models of electricity and chemical consumption for individual drinking water unit processes are used to estimate embedded NO x , SO 2 , PM 2.5 , and CO 2 emissions on a cubic meter basis. We estimate air emission damages from currently installed treatment processes at U.S. drinking water facilities to be on the order of $500 million USD annually. Fully complying with six promulgated and proposed rules would increase baseline air emission damages by approximately 50%, with three-quarters of these damages originating from chemical manufacturing. Despite the magnitude of these air emission damages, the net benefit of currently implemented rules remains positive. For some proposed rules, however, the promise of net benefits remains contingent on technology choice.

  7. Modelling earth current precursors in earthquake prediction

    Directory of Open Access Journals (Sweden)

    R. Di Maio

    1997-06-01

    Full Text Available This paper deals with the theory of earth current precursors of earthquake. A dilatancy-diffusion-polarization model is proposed to explain the anomalies of the electric potential, which are observed on the ground surface prior to some earthquakes. The electric polarization is believed to be the electrokinetic effect due to the invasion of fluids into new pores, which are opened inside a stressed-dilated rock body. The time and space variation of the distribution of the electric potential in a layered earth as well as in a faulted half-space is studied in detail. It results that the surface response depends on the underground conductivity distribution and on the relative disposition of the measuring dipole with respect to the buried bipole source. A field procedure based on the use of an areal layout of the recording sites is proposed, in order to obtain the most complete information on the time and space evolution of the precursory phenomena in any given seismic region.

  8. The 'OMITRON' and 'MODEL OMITRON' proposed experiments

    International Nuclear Information System (INIS)

    Sestero, A.

    1997-12-01

    In the present paper the main features of the OMITRON and MODEL OMITRON proposed high field tokamaks are illustrated. Of the two, OMITRON is an ambitious experiment, aimed at attaining plasma burning conditions. its key physics issues are discussed, and a comparison is carried out with corresponding physics features in ignition experiments such as IGNITOR and ITER. Chief asset and chief challenge - in both OMITRON and MODEL OMITRON is the conspicuous 20 Tesla toroidal field value on the plasma axis. The advanced features of engineering which consent such a reward in terms of toroidal magnet performance are discussed in convenient depth and detail. As for the small, propaedeutic device MODEL OMITRON among its goals one must rank the purpose of testing key engineering issues in vivo, which are vital for the larger and more expensive parent device. Besides that, however - as indicated by ad hoc performed scoping studies - the smaller machine is found capable also of a number of quite interesting physics investigations in its own right

  9. An analytical gate tunneling current model for MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Kazerouni, Iman Abaspur, E-mail: imanabaspur@gmail.com; Hosseini, Seyed Ebrahim [Sabzevar Tarbiat Moallem University, Electrical and Computer Department (Iran, Islamic Republic of)

    2012-03-15

    Gate tunneling current of MOSFETs is an important factor in modeling ultra small devices. In this paper, gate tunneling in present-generation MOSFETs is studied. In the proposed model, we calculate the electron wave function at the semiconductor-oxide interface and inversion charge by treating the inversion layer as a potential well, including some simplifying assumptions. Then we compute the gate tunneling current using the calculated wave function. The proposed model results have an excellent agreement with experimental results in the literature.

  10. Superconducting current in a bisoliton superconductivity model

    International Nuclear Information System (INIS)

    Ermakov, V.N.; Kruchinin, S.P.; Ponezha, E.A.

    1991-01-01

    It is shown that the transition into a superconducting state with the current which is described by a bisoliton superconductivity model is accompanied by the deformation of the spectrum of one-particle states of the current carriers. The deformation value is proportional to the conducting current force. The residuaby resistance in such state is absent

  11. Analytic modeling of axisymmetric disruption halo currents

    International Nuclear Information System (INIS)

    Humphreys, D.A.; Kellman, A.G.

    1999-01-01

    Currents which can flow in plasma facing components during disruptions pose a challenge to the design of next generation tokamaks. Induced toroidal eddy currents and both induced and conducted poloidal ''halo'' currents can produce design-limiting electromagnetic loads. While induction of toroidal and poloidal currents in passive structures is a well-understood phenomenon, the driving terms and scalings for poloidal currents flowing on open field lines during disruptions are less well established. A model of halo current evolution is presented in which the current is induced in the halo by decay of the plasma current and change in enclosed toroidal flux while being convected into the halo from the core by plasma motion. Fundamental physical processes and scalings are described in a simplified analytic version of the model. The peak axisymmetric halo current is found to depend on halo and core plasma characteristics during the current quench, including machine and plasma dimensions, resistivities, safety factor, and vertical stability growth rate. Two extreme regimes in poloidal halo current amplitude are identified depending on the minimum halo safety factor reached during the disruption. A 'type I' disruption is characterized by a minimum safety factor that remains relatively high (typically 2 - 3, comparable to the predisruption safety factor), and a relatively low poloidal halo current. A 'type II' disruption is characterized by a minimum safety factor comparable to unity and a relatively high poloidal halo current. Model predictions for these two regimes are found to agree well with halo current measurements from vertical displacement event disruptions in DIII-D [T. S. Taylor, K. H. Burrell, D. R. Baker, G. L. Jackson, R. J. La Haye, M. A. Mahdavi, R. Prater, T. C. Simonen, and A. D. Turnbull, open-quotes Results from the DIII-D Scientific Research Program,close quotes in Proceedings of the 17th IAEA Fusion Energy Conference, Yokohama, 1998, to be published in

  12. Neutral currents and parity breakdown in atomic transitions: three proposed experiments

    International Nuclear Information System (INIS)

    Bloom, S.D.

    1976-01-01

    This paper describes three proposed experiments for observing the breakdown of parity in atomic transitions due to the exchange of neutral, parity-violating currents arising from some of the new gauge models (e.g., the Weinberg model) for the weak interaction. The experiments are based on exploiting a suggestion, by Bouchiat and Bouchiat, that modern laser technology be utilized to produce intense, monochromatic, and polarized photon beams with which to excite forbidden atomic transitions of the basic form parallel ns 1 / 2 broken bracket → parallel n's 1 / 2 broken bracket. The asymmetries (of the order of 10 -4 ) in the de-exitation processes then signal the presence of the parity-violating components due to the neutral currents. In all three experiments suggested here, the use of multiple (uncollimated)atomic beams as targets forms a basic part, and their advantages over a temperature-equilibrium vapor are described. The first experiment uses 55 Cs atomic beams as a target; the second uses 37 Rb in conjunction with a superstrong magnetic field (approximately 80 kG); the third uses 81 Tl and requires frequency doubling of the exciting laser beam. All three experiments appear to be quite feasible, and, given the requisite equipment (much of which is or soon will be commercially available), they could yield definitive results in a period of a few months

  13. Computer modelling of superconductive fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Weller, R.A.; Campbell, A.M.; Coombs, T.A.; Cardwell, D.A.; Storey, R.J. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Hancox, J. [Rolls Royce, Applied Science Division, Derby (United Kingdom)

    1998-05-01

    Investigations are being carried out on the use of superconductors for fault current limiting applications. A number of computer programs are being developed to predict the behavior of different `resistive` fault current limiter designs under a variety of fault conditions. The programs achieve solution by iterative methods based around real measured data rather than theoretical models in order to achieve accuracy at high current densities. (orig.) 5 refs.

  14. Adaptive Maneuvering Frequency Method of Current Statistical Model

    Institute of Scientific and Technical Information of China (English)

    Wei Sun; Yongjian Yang

    2017-01-01

    Current statistical model(CSM) has a good performance in maneuvering target tracking. However, the fixed maneuvering frequency will deteriorate the tracking results, such as a serious dynamic delay, a slowly converging speedy and a limited precision when using Kalman filter(KF) algorithm. In this study, a new current statistical model and a new Kalman filter are proposed to improve the performance of maneuvering target tracking. The new model which employs innovation dominated subjection function to adaptively adjust maneuvering frequency has a better performance in step maneuvering target tracking, while a fluctuant phenomenon appears. As far as this problem is concerned, a new adaptive fading Kalman filter is proposed as well. In the new Kalman filter, the prediction values are amended in time by setting judgment and amendment rules,so that tracking precision and fluctuant phenomenon of the new current statistical model are improved. The results of simulation indicate the effectiveness of the new algorithm and the practical guiding significance.

  15. Current approaches to gene regulatory network modelling

    Directory of Open Access Journals (Sweden)

    Brazma Alvis

    2007-09-01

    Full Text Available Abstract Many different approaches have been developed to model and simulate gene regulatory networks. We proposed the following categories for gene regulatory network models: network parts lists, network topology models, network control logic models, and dynamic models. Here we will describe some examples for each of these categories. We will study the topology of gene regulatory networks in yeast in more detail, comparing a direct network derived from transcription factor binding data and an indirect network derived from genome-wide expression data in mutants. Regarding the network dynamics we briefly describe discrete and continuous approaches to network modelling, then describe a hybrid model called Finite State Linear Model and demonstrate that some simple network dynamics can be simulated in this model.

  16. Students’ mental model in electric current

    Science.gov (United States)

    Pramesti, Y. S.; Setyowidodo, I.

    2018-05-01

    Electricity is one of essential topic in learning physics. This topic was studied in elementary until university level. Although electricity was related to our daily activities, but it doesn’t ensure that students have the correct concept. The aim of this research was to investigate and then categorized the students’ mental model. Subject consisted of 59 students of mechanical engineering that studied Physics for Engineering. This study was used a qualitative approach that used in this research is phenomenology. Data were analyzed qualitatively by using pre-test, post-test, and investigation for discovering further information. Three models were reported, showing a pattern which related to individual way of thinking about electric current. The mental model that was discovered in this research are: 1) electric current as a flow; 2) electric current as a source of energy, 3) electric current as a moving charge.

  17. Experimental modeling of eddy current inspection capabilities

    International Nuclear Information System (INIS)

    Junker, W.R.; Clark, W.G.

    1984-01-01

    This chapter examines the experimental modeling of eddy current inspection capabilities based upon the use of liquid mercury samples designed to represent metal components containing discontinuities. A brief summary of past work with mercury modeling and a detailed discussion of recent experiments designed to further evaluate the technique are presented. The main disadvantages of the mercury modeling concept are that mercury is toxic and must be handled carefully, liquid mercury can only be used to represent nonferromagnetic materials, and wetting and meniscus problems can distort the effective size of artificial discontinuities. Artificial discontinuities placed in a liquid mercury sample can be used to represent discontinuities in solid metallic structures. Discontinuity size and type cannot be characterized from phase angle and signal amplitude data developed with a surface scanning, pancake-type eddy current probe. It is concluded that the mercury model approach can greatly enhance the overall understanding and applicability of eddy current inspection techniques

  18. Modelling and simulation of eddy current non-destructive testing

    International Nuclear Information System (INIS)

    Mansir, H.; Burais, N.; Nicolas, A.

    1986-01-01

    This paper presents the practical configuration for detecting cracks in conducting materials by eddy current non destructive testing. An electromagnetic field formulation is proposed using Maxwell's relations. Geometrical and physical properties of the crack are taken into account by several models, particularly with a new finite element called ''crack element''. Modelisation is applied to sensor impedance calculation with classical numerical methods [fr

  19. Higher quantum conserved current in a new completely integrable model

    International Nuclear Information System (INIS)

    Nissimov, E.R.

    1980-06-01

    The first higher local quantum conserved current is the recently proposed new completely integrable (2esup(βphi)+esup(-2βphi)) 2 model is explicitly constructed thus proving absence of particle production and factorization of multiparticle scattering. (author)

  20. Current density and continuity in discretized models

    International Nuclear Information System (INIS)

    Boykin, Timothy B; Luisier, Mathieu; Klimeck, Gerhard

    2010-01-01

    Discrete approaches have long been used in numerical modelling of physical systems in both research and teaching. Discrete versions of the Schroedinger equation employing either one or several basis functions per mesh point are often used by senior undergraduates and beginning graduate students in computational physics projects. In studying discrete models, students can encounter conceptual difficulties with the representation of the current and its divergence because different finite-difference expressions, all of which reduce to the current density in the continuous limit, measure different physical quantities. Understanding these different discrete currents is essential and requires a careful analysis of the current operator, the divergence of the current and the continuity equation. Here we develop point forms of the current and its divergence valid for an arbitrary mesh and basis. We show that in discrete models currents exist only along lines joining atomic sites (or mesh points). Using these results, we derive a discrete analogue of the divergence theorem and demonstrate probability conservation in a purely localized-basis approach.

  1. The Associative Basis of Scientific Creativity: A Model Proposal

    Directory of Open Access Journals (Sweden)

    Esra Kanli

    2014-06-01

    Full Text Available Creativity is accepted as an important part of scientific skills. Scientific creativity proceeds from a need or urge to solve a problem, and in-volves the production of original and useful ideas or products. Existing scientific creativity theories and tests do not feature the very im-portant thinking processes, such as analogical and associative thinking, which can be consid-ered crucial in creative scientific problem solv-ing. Current study’s aim is to provide an alter-native model and explicate the associative basis of scientific creativity. Emerging from the re-viewed theoretical framework, Scientific Asso-ciations Model is proposed. This model claims that, similarity and mediation constitutes the basis of creativity and focuses on three compo-nents namely; associative thinking, analogical thinking (analogical reasoning & analogical problem solving and insight which are consid-ered to be main elements of scientific associa-tive thinking.

  2. Child-Labor Proposal Eyes Private Model

    Science.gov (United States)

    Cech, Scott J.

    2007-01-01

    Proposed child-labor-rule changes--the most ambitious in 30 years--would carve out a permanent exemption to U.S. Department of Labor regulations for the work-study program run by a national network of Roman Catholic high schools. The program is a requirement of the Chicago-based Cristo Rey Network, which now has 12 high schools around the country…

  3. Paralegals in Corrections: A Proposed Model.

    Science.gov (United States)

    McShane, Marilyn D.

    1987-01-01

    Describes the legal assistance program currently offered by the Texas Department of Corrections which demonstrates the wide range of questions and problems that the paralegal can address. Reviews paralegal's functions in the prison setting and the services they can provide in assisting prisoners to maintain their rights. (Author/ABB)

  4. Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft

    Science.gov (United States)

    Sadey, David J.; Taylor, Linda M.; Beach, Raymond F.

    2017-01-01

    The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as strategic thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of alternating current (AC) and direct current (DC) for power generation, transmission, and distribution. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power system, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of doubly-fed induction machines (DFIMs), which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the activity along with the system architecture, development status, and preliminary results.

  5. MASCOTTE: analytical model of eddy current signals

    International Nuclear Information System (INIS)

    Delsarte, G.; Levy, R.

    1992-01-01

    Tube examination is a major application of the eddy current technique in the nuclear and petrochemical industries. Such examination configurations being specially adapted to analytical modes, a physical model is developed on portable computers. It includes simple approximations made possible by the effective conditions of the examinations. The eddy current signal is described by an analytical formulation that takes into account the tube dimensions, the sensor conception, the physical characteristics of the defect and the examination parameters. Moreover, the model makes it possible to associate real signals and simulated signals

  6. Eddy current modeling in linear and nonlinear multifilamentary composite materials

    Science.gov (United States)

    Menana, Hocine; Farhat, Mohamad; Hinaje, Melika; Berger, Kevin; Douine, Bruno; Lévêque, Jean

    2018-04-01

    In this work, a numerical model is developed for a rapid computation of eddy currents in composite materials, adaptable for both carbon fiber reinforced polymers (CFRPs) for NDT applications and multifilamentary high temperature superconductive (HTS) tapes for AC loss evaluation. The proposed model is based on an integro-differential formulation in terms of the electric vector potential in the frequency domain. The high anisotropy and the nonlinearity of the considered materials are easily handled in the frequency domain.

  7. A Proposed Curriculum Model for Geriatric Optometry.

    Science.gov (United States)

    Rosenbloom, Albert A.

    1985-01-01

    A model for a geriatric optometry curriculum that defines key content areas and addresses the values essential for effective practice and basic therapeutic modalities used in treatment regimens with older adults is outlined. (MSE)

  8. A proposed model for construction project management ...

    African Journals Online (AJOL)

    Keywords: Communication skills and leadership model, construction project ..... help a manager handle stress and break tension (Gido & Clements,. 2012: 331; Harrin .... production and management of projects, the higher the demand for.

  9. A proposed model for construction project management ...

    African Journals Online (AJOL)

    Log in or Register to get access to full text downloads. ... (decision-making, problem-solving, listening, verbal competency, motivation, persuasion, ... Keywords: Communication skills and leadership model, construction project management, ...

  10. Current definition and a generalized federbush model

    International Nuclear Information System (INIS)

    Singh, L.P.S.; Hagen, C.R.

    1978-01-01

    The Federbush model is studied, with particular attention being given to the definition of currents. Inasmuch as there is no a priori restriction of local gauge invariance, the currents in the interacting case can be defined more generally than in Q.E.D. It is found that two arbitrary parameters are thereby introduced into the theory. Lowest order perturbation calculations for the current correlation functions and the Fermion propagators indicate that the theory admits a whole class of solutions dependent upon these parameters with the closed solution of Federbush emerging as a special case. The theory is shown to be locally covariant, and a conserved energy--momentum tensor is displayed. One finds in addition that the generators of gauge transformations for the fields are conserved. Finally it is shown that the general theory yields the Federbush solution if suitable Thirring model type counterterms are added

  11. Virtual Universities: Current Models and Future Trends.

    Science.gov (United States)

    Guri-Rosenblit, Sarah

    2001-01-01

    Describes current models of distance education (single-mode distance teaching universities, dual- and mixed-mode universities, extension services, consortia-type ventures, and new technology-based universities), including their merits and problems. Discusses future trends in potential student constituencies, faculty roles, forms of knowledge…

  12. 78 FR 54622 - Proposed Information Collection; Comment Request; Current Population Survey, Annual Social and...

    Science.gov (United States)

    2013-09-05

    ... DEPARTMENT OF COMMERCE Census Bureau Proposed Information Collection; Comment Request; Current Population Survey, Annual Social and Economic Supplement AGENCY: U.S. Census Bureau, Commerce. ACTION: Notice... designed to create a marketplace of private health insurance options for individuals and small businesses...

  13. Quasi-equilibrium channel model of an constant current arc

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2003-01-01

    Full Text Available The rather simple method of calculation of electronic and gas temperature in the channel of arc of plasma generator is offered. This method is based on self-consistent two-temperature channel model of an electric arc. The method proposed enables to obtain radial allocation of gas and electronic temperatures in a non-conducting zone of an constant current arc, for prescribed parameters of discharge (current intensity and power of the discharge, with enough good precision. The results obtained can be used in model and engineering calculations to estimate gas and electronic temperatures in the channel of an arc plasma generator.

  14. Current algebra, statistical mechanics and quantum models

    Science.gov (United States)

    Vilela Mendes, R.

    2017-11-01

    Results obtained in the past for free boson systems at zero and nonzero temperatures are revisited to clarify the physical meaning of current algebra reducible functionals which are associated to systems with density fluctuations, leading to observable effects on phase transitions. To use current algebra as a tool for the formulation of quantum statistical mechanics amounts to the construction of unitary representations of diffeomorphism groups. Two mathematical equivalent procedures exist for this purpose. One searches for quasi-invariant measures on configuration spaces, the other for a cyclic vector in Hilbert space. Here, one argues that the second approach is closer to the physical intuition when modelling complex systems. An example of application of the current algebra methodology to the pairing phenomenon in two-dimensional fermion systems is discussed.

  15. Dual resonance models and their currents

    International Nuclear Information System (INIS)

    Johnson, E.A.

    1978-01-01

    It is shown how dual resonance models were rederived from the concept of a string tracing out a surface in space-time. Thus, interacting strings reproduce the dual amplitudes. A scheme for tackling the unitarity problem began to develop. As a consistent theory of hadronic processes began to be built, workers at the same time were naturally led to expect that leptons could be included with hadrons in a unified dual theory. Thus, there is a search for dual amplitudes which would describe interactions between hadrons and currents (for example, electrons), as well as interactions involving only hadrons. Such amplitudes, it is believed, will be the correct ones, describing the real world. Such amplitudes will provide valuable information concerning such things as hadronic form factors. The great difficulties in building current-amplitudes with the required properties of proper factorization on a good spectrum, duality, current algebra, and proper asymptotic behavior are described. Dual models at the present time require for consistency, an intercept value of α 0 = 1 and a dimension value of d = 26 (or d = 10). There have been speculations that the unphysical dimension may be made physical by associating the ''extra dimensions'' with certain internal degrees of freedom. However, it is desired that the theory itself, force the dimension d = 4. It is quite possible that the dimension problem and the intercept problem are tied together and that resolving either problem will resolve the other. Order by order, a new dual current is constructed that is manifestly factorizable and which appears to be valid for arbitrary space-time dimension. The fact that this current is not bound at d = 26, leads to interesting speculations on the nature of dual currents

  16. Modelling of current loads on aquaculture net cages

    Science.gov (United States)

    Kristiansen, Trygve; Faltinsen, Odd M.

    2012-10-01

    In this paper we propose and discuss a screen type of force model for the viscous hydrodynamic load on nets. The screen model assumes that the net is divided into a number of flat net panels, or screens. It may thus be applied to any kind of net geometry. In this paper we focus on circular net cages for fish farms. The net structure itself is modelled by an existing truss model. The net shape is solved for in a time-stepping procedure that involves solving a linear system of equations for the unknown tensions at each time step. We present comparisons to experiments with circular net cages in steady current, and discuss the sensitivity of the numerical results to a set of chosen parameters. Satisfactory agreement between experimental and numerical prediction of drag and lift as function of the solidity ratio of the net and the current velocity is documented.

  17. Computer modelling of eddy current probes

    International Nuclear Information System (INIS)

    Sullivan, S.P.

    1992-01-01

    Computer programs have been developed for modelling impedance and transmit-receive eddy current probes in two-dimensional axis-symmetric configurations. These programs, which are based on analytic equations, simulate bobbin probes in infinitely long tubes and surface probes on plates. They calculate probe signal due to uniform variations in conductor thickness, resistivity and permeability. These signals depend on probe design and frequency. A finite element numerical program has been procured to calculate magnetic permeability in non-linear ferromagnetic materials. Permeability values from these calculations can be incorporated into the above analytic programs to predict signals from eddy current probes with permanent magnets in ferromagnetic tubes. These programs were used to test various probe designs for new testing applications. Measurements of magnetic permeability in magnetically biased ferromagnetic materials have been performed by superimposing experimental signals, from special laboratory ET probes, on impedance plane diagrams calculated using these programs. (author). 3 refs., 2 figs

  18. Developmental trauma, complex PTSD, and the current proposal of DSM-5

    Directory of Open Access Journals (Sweden)

    Vedat Sar

    2011-03-01

    Full Text Available This paper evaluates representation of clinical consequences of developmental psychological trauma in the current proposal of DSM-5. Despite intensive efforts by its proponents for two decades, it is not known yet if Complex PTSD will take a place in the final version of DSM-5. Recognition of dissociative character of several symptom dimensions and introduction of items about negative affects such as shame and guilt imply an indirect improvement toward better coverage of the consequences of developmental trauma in the existing category of PTSD. As disorders with highest prevalence of chronic traumatization in early years of life, dissociative disorders and personality disorder of borderline type are maintained as DSM-5 categories; however, recognition of a separate type of trauma-related personality disorder is unlikely. While a preschooler age variant of PTSD is under consideration, the proposed diagnosis of Developmental Trauma Disorder (child version of Complex PTSD has not secured a place in the DSM-5 yet. We welcome considerations of subsuming Adjustment Disorders, Acute Stress Disorder, PTSD, and Dissociative Disorders under one rubric, i.e., Section of Trauma, Stress, or Event Related Disorders. Given the current conceptualization of DSM-5, this paper proposes Complex PTSD to be a subtype of the DSM-5 PTSD. Composition of a trauma-related disorders section would facilitate integration of knowledge and expertise about interrelated and overlapping consequences of trauma.For the abstract or full text in other languages, please see Supplementary files under Reading Tools online

  19. Modeling of Tsunami Currents in Harbors

    Science.gov (United States)

    Lynett, P. J.

    2010-12-01

    Extreme events, such as large wind waves and tsunamis, are well recognized as a damaging hazard to port and harbor facilities. Wind wave events, particularly those with long period spectral components or infragravity wave generation, can excite resonance inside harbors leading to both large vertical motions and strong currents. Tsunamis can cause great damage as well. The geometric amplification of these very long waves can create large vertical motions in the interior of a harbor. Additionally, if the tsunami is composed of a train of long waves, which it often is, resonance can be easily excited. These long wave motions create strong currents near the node locations of resonant motions, and when interacting with harbor structures such as breakwaters, can create intense turbulent rotational structures, typical in the form of large eddies or gyres. These gyres have tremendous transport potential, and have been observed to break mooring lines, and even cause ships to be trapped inside the rotation, moving helplessly with the flow until collision, grounding, or dissipation of the eddy (e.g. Okal et al., 2006). This presentation will introduce the traditional theory used to predict wave impacts on harbors, discussing both how these models are practically useful and in what types of situations require a more accurate tool. State-of-the-art numerical models will be introduced, with a focus on recent developments in Boussinesq-type modeling. The Boussinesq equations model can account the dispersive, turbulent and rotational flow properties frequently observed in nature. Also they have the ability to coupling currents and waves and can predict nonlinear wave propagation over uneven bottom from deep (or intermediate) water area to shallow water area. However, during the derivation of a 2D-horizontal equation set, some 3D flow features, such those driven by as the dispersive stresses and the effects of the unresolved small scale 3D turbulence, are excluded. Consequently

  20. A Proposal for a Flexible Trend Specification in DSGE Models

    Directory of Open Access Journals (Sweden)

    Slanicay Martin

    2016-06-01

    Full Text Available In this paper I propose a flexible trend specification for estimating DSGE models on log differences. I demonstrate this flexible trend specification on a New Keynesian DSGE model of two economies, which I consequently estimate on data from the Czech economy and the euro area, using Bayesian techniques. The advantage of the trend specification proposed is that the trend component and the cyclical component are modelled jointly in a single model. The proposed trend specification is flexible in the sense that smoothness of the trend can be easily modified by different calibration of some of the trend parameters. The results suggest that this method is capable of finding a very reasonable trend in the data. Moreover, comparison of forecast performance reveals that the proposed specification offers more reliable forecasts than the original variant of the model.

  1. Views of surgery program directors on the current ACGME and proposed IOM duty-hour standards.

    Science.gov (United States)

    Willis, Ross E; Coverdill, James E; Mellinger, John D; Collins, J Craig; Potts, John R; Dent, Daniel L

    2009-01-01

    The purpose of this study was to survey the experiences of surgery program directors with the current Accreditation Council for Graduate Medical Education (ACGME) duty-hour standards and views of the Institute of Medicine (IOM) proposed duty-hour recommendations. A total of 118 program directors (47.6% of all surgery programs in the US) responded to the survey. Results showed that the current duty-hour standards have hindered clinical education opportunities by reducing or eliminating rotations on many services, didactic teaching conferences, and clinical bedside teaching opportunities. Additionally, patient safety has been compromised by frequent hand offs of care. Most IOM recommendations were perceived as extremely difficult or impossible to implement, with the exception of the moonlighting recommendation. The results indicated that adopting the IOM recommendations is not feasible given current workforce limitations, and most program directors supported maintaining the current duty-hour standards until such time as there is evidence-based outcomes research to direct change. The conclusion was that the current ACGME duty-hour standards have reduced teaching opportunities and narrowed the scope of training.

  2. A Proposed Systems Model for Socializing the Graduate Writer

    Science.gov (United States)

    Jones, David R.

    2018-01-01

    Although researchers chorus the need to support graduate students toward higher levels of writing proficiency, their findings lack a holistic model for doing so. A model emerges upon scrutiny of the factors that have been implicated in supporting writing proficiency. In the proposed model, a socialization theory fits as a proximal process into the…

  3. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  4. Regional economic effects of current and proposed management alternatives for Arrowwood National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Arrowwood National Wildlife Refuge (NWR), located along the James River in east central North Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Arrowwood NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  5. A proposed best practice model validation framework for banks

    Directory of Open Access Journals (Sweden)

    Pieter J. (Riaan de Jongh

    2017-06-01

    Full Text Available Background: With the increasing use of complex quantitative models in applications throughout the financial world, model risk has become a major concern. The credit crisis of 2008–2009 provoked added concern about the use of models in finance. Measuring and managing model risk has subsequently come under scrutiny from regulators, supervisors, banks and other financial institutions. Regulatory guidance indicates that meticulous monitoring of all phases of model development and implementation is required to mitigate this risk. Considerable resources must be mobilised for this purpose. The exercise must embrace model development, assembly, implementation, validation and effective governance. Setting: Model validation practices are generally patchy, disparate and sometimes contradictory, and although the Basel Accord and some regulatory authorities have attempted to establish guiding principles, no definite set of global standards exists. Aim: Assessing the available literature for the best validation practices. Methods: This comprehensive literature study provided a background to the complexities of effective model management and focussed on model validation as a component of model risk management. Results: We propose a coherent ‘best practice’ framework for model validation. Scorecard tools are also presented to evaluate if the proposed best practice model validation framework has been adequately assembled and implemented. Conclusion: The proposed best practice model validation framework is designed to assist firms in the construction of an effective, robust and fully compliant model validation programme and comprises three principal elements: model validation governance, policy and process.

  6. A Proposed Conceptual Model of Military Medical Readiness

    National Research Council Canada - National Science Library

    Van Hall, Brian M

    2007-01-01

    .... The purpose of this research is to consolidate existing literature on the latent variable of medical readiness, and to propose a composite theoretical model of medical readiness that may provide...

  7. Linear regression crash prediction models : issues and proposed solutions.

    Science.gov (United States)

    2010-05-01

    The paper develops a linear regression model approach that can be applied to : crash data to predict vehicle crashes. The proposed approach involves novice data aggregation : to satisfy linear regression assumptions; namely error structure normality ...

  8. Parametric overdispersed frailty models for current status data.

    Science.gov (United States)

    Abrams, Steven; Aerts, Marc; Molenberghs, Geert; Hens, Niel

    2017-12-01

    Frailty models have a prominent place in survival analysis to model univariate and multivariate time-to-event data, often complicated by the presence of different types of censoring. In recent years, frailty modeling gained popularity in infectious disease epidemiology to quantify unobserved heterogeneity using Type I interval-censored serological data or current status data. In a multivariate setting, frailty models prove useful to assess the association between infection times related to multiple distinct infections acquired by the same individual. In addition to dependence among individual infection times, overdispersion can arise when the observed variability in the data exceeds the one implied by the model. In this article, we discuss parametric overdispersed frailty models for time-to-event data under Type I interval-censoring, building upon the work by Molenberghs et al. (2010) and Hens et al. (2009). The proposed methodology is illustrated using bivariate serological data on hepatitis A and B from Flanders, Belgium anno 1993-1994. Furthermore, the relationship between individual heterogeneity and overdispersion at a stratum-specific level is studied through simulations. Although it is important to account for overdispersion, one should be cautious when modeling both individual heterogeneity and overdispersion based on current status data as model selection is hampered by the loss of information due to censoring. © 2017, The International Biometric Society.

  9. Proposed high voltage power supply for the ITER relevant lower hybrid current drive system

    International Nuclear Information System (INIS)

    Sharma, P.K.; Kazarian, F.; Garibaldi, P.; Gassman, T.; Artaud, J.F.; Bae, Y.S.; Belo, J.; Berger-By, G.; Bernard, J.M.; Cara, Ph.; Cardinali, A.; Castaldo, C.; Ceccuzzi, S.; Cesario, R.; Decker, J.; Delpech, L.; Ekedahl, A.; Garcia, J.; Goniche, M.; Guilhem, D.

    2011-01-01

    In the framework of the EFDA task HCD-08-03-01, the ITER lower hybrid current drive (LHCD) system design has been reviewed. The system aims to generate 24 MW of RF power at 5 GHz, of which 20 MW would be coupled to the plasmas. The present state of the art does not allow envisaging a unitary output of the klystrons exceeding 500 kW, so the project is based on 48 klystron units, leaving some margin when the transmission lines losses are taken into account. A high voltage power supply (HVPS), required to operate the klystrons, is proposed. A single HVPS would be used to feed and operate four klystrons in parallel configuration. Based on the above considerations, it is proposed to design and develop twelve HVPS, based on pulse step modulator (PSM) technology, each rated for 90 kV/90 A. This paper describes in details, the typical electrical requirements and the conceptual design of the proposed HVPS for the ITER LHCD system.

  10. Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

    OpenAIRE

    Zhijian Fang; Junhua Wang; Shanxu Duan; Liangle Xiao; Guozheng Hu; Qisheng Liu

    2018-01-01

    In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feed...

  11. Gamification in online education: proposal for a participatory learning model

    Directory of Open Access Journals (Sweden)

    Fabiana Bigão Silva

    2017-09-01

    Full Text Available Empirical studies have suggested limitations on the form of application of gamification mechanics in the context of online education. These mechanics have been applied without reference to a theoretical model dedicated to this type of education. The objective of the paper is to propose a model for a gamified platform for online education that contributes to a more participatory learning, taking into account the different student profiles. Based on literature review about approaches to gamification systems design, a set of steps was followed in order to develop a generic model for a framework dedicated to online education. The model proposed is based on the Educational Gamification Design Principles proposed by Dicheva et al. (2015. The model may contribute to the promotion of participatory learning, taking into account the different student profiles. The results of such evaluation will be published in the future.

  12. Proposal for a Domain Wall Nano-Oscillator driven by Non-uniform Spin Currents

    Science.gov (United States)

    Sharma, Sanchar; Muralidharan, Bhaskaran; Tulapurkar, Ashwin

    2015-09-01

    We propose a new mechanism and a related device concept for a robust, magnetic field tunable radio-frequency (rf) oscillator using the self oscillation of a magnetic domain wall subject to a uniform static magnetic field and a spatially non-uniform vertical dc spin current. The self oscillation of the domain wall is created as it translates periodically between two unstable positions, one being in the region where both the dc spin current and the magnetic field are present, and the other, being where only the magnetic field is present. The vertical dc spin current pushes it away from one unstable position while the magnetic field pushes it away from the other. We show that such oscillations are stable under noise and can exhibit a quality factor of over 1000. A domain wall under dynamic translation, not only being a source for rich physics, is also a promising candidate for advancements in nanoelectronics with the actively researched racetrack memory architecture, digital and analog switching paradigms as candidate examples. Devising a stable rf oscillator using a domain wall is hence another step towards the realization of an all domain wall logic scheme.

  13. A Modified Microfinance Model Proposed for the United States

    Directory of Open Access Journals (Sweden)

    Eldon H Bernstein

    2014-07-01

    While the goal in the traditional model in developing markets is the elimination of poverty, we show how those critical conditions help to explain the lack of success in the United States.  We propose a modified model whose goal is the creation of an entrepreneurial venture or improving the performance of an existing small enterprise.

  14. Ecological models and pesticide risk assessment: current modeling practice.

    Science.gov (United States)

    Schmolke, Amelie; Thorbek, Pernille; Chapman, Peter; Grimm, Volker

    2010-04-01

    Ecological risk assessments of pesticides usually focus on risk at the level of individuals, and are carried out by comparing exposure and toxicological endpoints. However, in most cases the protection goal is populations rather than individuals. On the population level, effects of pesticides depend not only on exposure and toxicity, but also on factors such as life history characteristics, population structure, timing of application, presence of refuges in time and space, and landscape structure. Ecological models can integrate such factors and have the potential to become important tools for the prediction of population-level effects of exposure to pesticides, thus allowing extrapolations, for example, from laboratory to field. Indeed, a broad range of ecological models have been applied to chemical risk assessment in the scientific literature, but so far such models have only rarely been used to support regulatory risk assessments of pesticides. To better understand the reasons for this situation, the current modeling practice in this field was assessed in the present study. The scientific literature was searched for relevant models and assessed according to nine characteristics: model type, model complexity, toxicity measure, exposure pattern, other factors, taxonomic group, risk assessment endpoint, parameterization, and model evaluation. The present study found that, although most models were of a high scientific standard, many of them would need modification before they are suitable for regulatory risk assessments. The main shortcomings of currently available models in the context of regulatory pesticide risk assessments were identified. When ecological models are applied to regulatory risk assessments, we recommend reviewing these models according to the nine characteristics evaluated here. (c) 2010 SETAC.

  15. Regional economic impacts of current and proposed management alternatives for Charles M. Russell National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Ishizaki, Asuka; Ritten, John

    2013-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. Charles M. Russell (CMR) National Wildlife Refuge, located in north-central Montana, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for the Refuge must contain an analysis of expected effects associated with current and proposed refuge-management strategies. For refuge CCP planning, an economic analysis provides a means of estimating how current management (No Action Alternative) and proposed management activities (Alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates a refuge’s contribution to the local community; and (2) it can help in determining whether economic effects are or are not a real concern in choosing among management alternatives. It is important to note that the economic value of a refuge encompasses more than just the impacts on the regional economy. Refuges also provide substantial nonmarket values (values for items not exchanged in established markets) such as maintaining endangered species, preserving wetlands, educating future generations, and adding stability to the ecosystem (Carver and Caudill, 2007). However, quantifying these types of nonmarket values is beyond the scope of this study. This report first presents a description of the local community and economy near the Refuge. Next, the methods used to conduct a regional economic impact analysis are described. An analysis of the final CCP management strategies that could affect stakeholders and residents and the local economy is then presented. The refuge management activities of economic concern in this analysis are:

  16. Proposal for product development model focused on ce certification methodology

    Directory of Open Access Journals (Sweden)

    Nathalia Marcia Goulart Pinheiro

    2015-09-01

    Full Text Available This paper presents a critical analysis comparing 21 product development models in order to identify whether these structures meet the demands Product Certification of the European Community (CE. Furthermore, it presents a product development model, comprising the steps in the models analyzed, including improvements in activities for referred product certification. The proposed improvements are justified by the growing quest for the internationalization of products and processes within companies.

  17. Fokker-Planck modeling of current penetration during electron cyclotron current drive

    International Nuclear Information System (INIS)

    Merkulov, A.; Westerhof, E.; Schueller, F. C.

    2007-01-01

    The current penetration during electron cyclotron current drive (ECCD) on the resistive time scale is studied with a Fokker-Planck simulation, which includes a model for the magnetic diffusion that determines the parallel electric field evolution. The existence of the synergy between the inductive electric field and EC driven current complicates the process of the current penetration and invalidates the standard method of calculation in which Ohm's law is simply approximated by j-j cd =σE. Here it is proposed to obtain at every time step a self-consistent approximation to the plasma resistivity from the Fokker-Planck code, which is then used in a concurrent calculation of the magnetic diffusion equation in order to obtain the inductive electric field at the next time step. A series of Fokker-Planck calculations including a self-consistent evolution of the inductive electric field has been performed. Both the ECCD power and the electron density have been varied, thus varying the well known nonlinearity parameter for ECCD P rf [MW/m -3 ]/n e 2 [10 19 m -3 ] [R. W. Harvey et al., Phys. Rev. Lett 62, 426 (1989)]. This parameter turns out also to be a good predictor of the synergetic effects. The results are then compared with the standard method of calculations of the current penetration using a transport code. At low values of the Harvey parameter, the standard method is in quantitative agreement with Fokker-Planck calculations. However, at high values of the Harvey parameter, synergy between ECCD and E parallel is found. In the case of cocurrent drive, this synergy leads to the generation of large amounts of nonthermal electrons and a concomitant increase of the electrical conductivity and current penetration time. In the case of countercurrent drive, the ECCD efficiency is suppressed by the synergy with E parallel while only a small amount of nonthermal electrons is produced

  18. Primary energy use for heating in the Swedish building sector-Current trends and proposed target

    International Nuclear Information System (INIS)

    Johansson, P.; Nylander, A.; Johnsson, F.

    2007-01-01

    One goal of the Swedish energy policy is to reduce the amount of electricity used for heating in the building sector. This means to reduce the primary energy used for heating which in this paper is analyzed in the context of various heating technologies and CO 2 emissions. The analysis is applied to a region in Sweden (southern Sweden) for which detailed information on the energy infrastructure (the capital stock of the buildings and heating systems together with geographical variations in heat intensity) is available from a previous work [Johansson, P., Nylander, A., Johnsson, F., 2005. Electricity dependency and CO 2 emissions from heating in the Swedish building sector-current trends in conflict with governmental policy? Energy policy] and which is large enough to be assumed representative for Sweden as a whole. The detailed mapping of the energy infrastructure allows a good estimate on the rate at which the energy system can be expected to be replaced with respect to economical lifetime of the capital stock (the year 2025 in this case). Two scenarios are investigated; a target scenario for which energy savings are employed (e.g. improving climate shell in buildings) and oil and most of the electricity used for heating purposes are phased out and a second for which the current trend in the heating market continues. In the target scenario it is shown that although only applying commercially competitive heating technologies, it is possible to achieve a 47% reduction in primary energy use for heating with a 34% decrease in heat demand together with significant reduction in CO 2 emissions. However, the scenario which continues the current trends on the heating market instead yields an increase (of about 10%) in primary energy use (reduction in conversion efficiency) of the heating system of the region over the period studied, in spite of a slight decrease in heat demand (9%, mainly due to energy efficiency measures) as well as in CO 2 emissions. In light of the

  19. A proposed residual stress model for oblique turning

    International Nuclear Information System (INIS)

    Elkhabeery, M. M.

    2001-01-01

    A proposed mathematical model is presented for predicting the residual stresses caused by turning. Effects of change in tool free length, cutting speed, feed rate, and the tensile strength of work piece material on the maximum residual stress are investigated. The residual stress distribution in the surface region due to turning under unlubricated condition is determined using a deflection etching technique. To reduce the number of experiments required and build the mathematical model for these variables, Response Surface Methodology (RSM) is used. In addition, variance analysis and an experimental check are conducted to determine the prominent parameters and the adequacy of the model. The results show that the tensile stress of the work piece material, cutting speed, and feed rate have significant effects on the maximum residual stresses. The proposed model, that offering good correlation between the experimental and predicted results, is useful in selecting suitable cutting parameters for the machining of different materials. (author)

  20. Main features of the proposed NCRP respiratory tract model

    International Nuclear Information System (INIS)

    Phalen, R.F.; Fisher, G.L.; Moss, O.R.; Schlesinger, R.B.; Swift, D.L.

    1991-01-01

    The proposed NCRP respiratory tract dosimetry model regions include the naso-oro-pharyngo-laryngeal (NOPL), the tracheobronchial (TB), the pulmonary (P), and the lymph nodes (LN). Input aerosol concentrations are derived from a consideration of particle-size-dependent inspirability. Particle deposition in the respiratory tract is modelled using the mechanisms of inertial impaction, sedimentation and diffusion. The rates of absorption of particles, and transport to the blood, have been derived from clearance data from people and laboratory animals. The effect of body growth on particle deposition is considered. Particle clearance rates are assumed to be independent of age. The proposed respiratory tract model differs significantly from the 1966 Task Group Model in that (1) inspirability is considered; (2) new sub-regions of the respiratory tract are considered; (3) absorption of materials by the blood is treated in a more sophisticated fashion; and (4) body size (and thus age) is taken into account. (author)

  1. A Proposed Model for Protein Crystal Nucleation and Growth

    Science.gov (United States)

    Pusey, Marc; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    How does one take a molecule, strongly asymmetric in both shape and charge distribution, and assemble it into a crystal? We propose a model for the nucleation and crystal growth process for tetragonal lysozyme, based upon fluorescence, light, neutron, and X-ray scattering data, size exclusion chromatography experiments, dialysis kinetics, AFM, and modeling of growth rate data, from this and other laboratories. The first species formed is postulated to be a 'head to side' dimer. Through repeating associations involving the same intermolecular interactions this grows to a 4(sub 3) helix structure, that in turn serves as the basic unit for nucleation and subsequent crystal growth. High salt attenuates surface charges while promoting hydrophobic interactions. Symmetry facilitates subsequent helix-helix self-association. Assembly stability is enhanced when a four helix structure is obtained, with each bound to two neighbors. Only two unique interactions are required. The first are those for helix formation, where the dominant interaction is the intermolecular bridging anion. The second is the anti-parallel side-by-side helix-helix interaction, guided by alternating pairs of symmetry related salt bridges along each side. At this stage all eight unique positions of the P4(sub3)2(sub 1),2(sub 1) unit cell are filled. The process is one of a) attenuating the most strongly interacting groups, such that b) the molecules begin to self-associate in defined patterns, so that c) symmetry is obtained, which d) propagates as a growing crystal. Simple and conceptually obvious in hindsight, this tells much about what we are empirically doing when we crystallize macromolecules. By adjusting the growth parameters we are empirically balancing the intermolecular interactions, preferentially attenuating the dominant strong (for lysozyme the charged groups) while strengthening the lesser strong (hydrophobic) interactions. In the general case for proteins the lack of a singularly defined

  2. Neutronic characteristics of coupled moderator proposed in integrated model

    International Nuclear Information System (INIS)

    Teshigawara, Makoto; Meigo, Shin-ichiro; Sakata, Hideaki; Kai, Tetsuya; Harada, Masahide; Ikeda, Yujiro; Watanabe, Noboru

    2001-05-01

    A pulsed spallation source for the materials science and the life science is currently developing for its construction in the High Intensity Proton Accelerator Project proposed jointly by the Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK). This report presents the analytical results of the neutronic characteristics of the coupled moderator based on the analytical results obtained by using an integrated model which has established on the extensive neutronic and technical study. Total heat deposition in a hydrogen (H 2 ) moderator working as the main moderator was about 420 W/MW. Maximum nuclear heat density in the H 2 moderator was about 1 W/cm 3 /MW. Also total heat deposition in a premoderator was about 9.2 kW/MW. The heat density of the premoderator was comparable to that of the moderator vessel made of aluminum alloy. The heat density of the premoderator and the moderator vessel is about 1.2-2 times higher than that of the hydrogen moderator. The temperature from 300 K to 400 K of the premoderator did not affect on neutron intensity of the H 2 moderator. This suggested an engineering advantage on the thermal and hydraulic design. 6000 or 7000 type of a aluminum alloy was considered from the viewpoint of the neutron beam transmission. The proton beams scattered by the proton beam window did not affect on the nuclear heating in the H 2 moderator. The heat deposition in the H 2 moderator and the neutron intensity of the H 2 moderator did not depend on the proton beam profile but it did on the distance between the proton beam and the moderator. (author)

  3. Regional economic analysis of current and proposed management alternatives for Rappahannock River Valley National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Donovan, Ryan

    2009-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan. The Comprehensive Conservation Plan must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. The Rappahannock River Valley National Wildlife Refuge (refuge) is in the process of developing a range of management goals, objectives, and strategies for the Comprehensive Conservation Plan. The Comprehensive Conservation Plan for the refuge must contain an analysis of expected effects associated with current and proposed refuge management strategies. The purpose of this study was to assess the regional economic implications associated with draft Comprehensive Conservation Plan management strategies. Special interest groups and local residents often criticize a change in refuge management, especially if there is a perceived negative impact to the local economy. Having objective data on economic impacts may show that these fears are overstated. Quite often, the extent of economic benefits a refuge provides to a local community is not fully recognized, yet at the same time the effects of negative changes is overstated. Spending associated with refuge recreational activities, such as wildlife viewing and hunting, can generate considerable tourist activity for surrounding communities. Additionally, refuge personnel typically spend considerable amounts of money purchasing supplies in local stores, repairing equipment and purchasing fuel at the local service stations, and reside and spend their salaries in the local community. For refuge Comprehensive Conservation Plan planning, a regional economic assessment provides a means of estimating how current management (no action alternative) and proposed management activities (alternatives) could affect the local economy. This type of analysis provides two critical pieces of

  4. Modeling of the Direct Current Generator Including the Magnetic Saturation and Temperature Effects

    Directory of Open Access Journals (Sweden)

    Alfonso J. Mercado-Samur

    2013-11-01

    Full Text Available In this paper the inclusion of temperature effect on the field resistance on the direct current generator model DC1A, which is valid to stability studies is proposed. First, the linear generator model is presented, after the effect of magnetic saturation and the change in the resistance value due to temperature produced by the field current are included. The comparison of experimental results and model simulations to validate the model is used. A direct current generator model which is a better representation of the generator is obtained. Visual comparison between simulations and experimental results shows the success of the proposed model, because it presents the lowest error of the compared models. The accuracy of the proposed model is observed via Modified Normalized Sum of Squared Errors index equal to 3.8979%.

  5. Proposed higher order continuum-based models for an elastic ...

    African Journals Online (AJOL)

    Three new variants of continuum-based models for an elastic subgrade are proposed. The subgrade is idealized as a homogenous, isotropic elastic layer of thickness H overlying a firm stratum. All components of the stress tensor in the subgrade are taken into account. Reasonable assumptions are made regarding the ...

  6. A Proposed Model of Jazz Theory Knowledge Acquisition

    Science.gov (United States)

    Ciorba, Charles R.; Russell, Brian E.

    2014-01-01

    The purpose of this study was to test a hypothesized model that proposes a causal relationship between motivation and academic achievement on the acquisition of jazz theory knowledge. A reliability analysis of the latent variables ranged from 0.92 to 0.94. Confirmatory factor analyses of the motivation (standardized root mean square residual…

  7. Model and performance of current sensor observers for a doubly fed induction generator

    DEFF Research Database (Denmark)

    Li, Hui; Yang, Chao; Hu, Yaogang

    2014-01-01

    . A stator and rotor current observer model, which is based on the state-space models of doubly fed induction generators, is then derived by using the stator and rotor voltage signals as inputs. To demonstrate the effectiveness of the proposed current observer, its dynamic performance is simulated using...

  8. Proposal of a theoretical model for the practical nurse

    Directory of Open Access Journals (Sweden)

    Dolores Abril Sabater

    2010-01-01

    Full Text Available AIM: To determine which model of nursing is proposed by care professionals and the reason for their choice. METHOD: cross-sectional, descriptive study design. The main variable: Nursing Models and Theories. As secondary variables were collected: age, gender, years of work experience, nursing model of basic training, and course/s related. We used a self-elaborated, anonymous questionnaire, passed between April - May, 2006. Not random sample.RESULTS: 546 nurses were invited, answered 205. 38 % response rate. Virginia Henderson was the more selected model (33%, however, 42% left the question blank, 12% indicated that they wanted to work under the guidance of a model. They selected a specifically model: Knowledge of the model to their training, standardization in other centers, the characteristics of the model itself and identification with its philosophy. They are not decided by a model by ignorance, lack of time and usefulness. CONCLUSIONS: The model chosen mostly for their daily work was Virginia Henderson model, so that knowledge of a model is the main reason for their election. Professionals who choose not to use the model in their practice realize offers and calling for resources, besides to explain the lack of knowledge on this topic. To advance the nursing profession is necessary that nurse is thought over widely on the abstract concepts of the theory in our context.

  9. A Framework Proposal For Choosing A New Business Implementation Model In Henkel

    OpenAIRE

    Li, Tsz Wan

    2015-01-01

    Henkel's New Business team is a corporate venturing unit that explores corporate entrepreneurial activities on behalf of Henkel Adhesives Technologies. The new business ideas are implemented through one of these models: incubator, venturing or innovation ecosystem. In current practice, there is no systematic framework in place to choose the implementation model. The goal of the thesis is to propose a framework for choosing the most appropriate model for implementation of a new business idea i...

  10. Proposal on ''standardized high current solid targets for cyclotron production of diagnostic and therapeutic radionuclides''

    International Nuclear Information System (INIS)

    Suparman, Ibon

    2000-01-01

    The Center for the Development of Radioisotopes and Radiopharmaceuticals - National Nuclear Energy Agency (P2RR-BATAN) has one Cyclotron type CS-30 with maximum 30 MeV proton energy. It is used since 1990 for 201 Tl production. The main use of 201 Tl in Indonesia is for diagnosis and assessment of myocardial ischaemia, especially diagnosis of coronary artery disease, viability of the heart muscle and forecasting the outcome for patients with coronary disease. The Cyclotron facility is supported with a solid target station, two hot cells and the chemical equipment for electroplating. The yield of 201 Tl production currently achieved around 40-50%. The irradiation technique and chemical separation should be improved. We are also very interested in the development of the production of 103 Pd via 103 Rh (p,n) 103 Pd reaction. The objective of this proposal will support the main program of the National Nuclear Energy Agency (BATAN) in enhancement of health care and in providing Cyclotron produced radiopharmaceuticals for hospitals

  11. Wetland Planning: Current Problems and Environmental Management Proposals at Supra-Municipal Scale (Spanish Mediterranean Coast

    Directory of Open Access Journals (Sweden)

    María-Teresa Sebastiá-Frasquet

    2014-03-01

    Full Text Available The policies that define the use and management of wetlands in Spain have undergone tremendous changes in recent decades. During the period of 1950–1980, Land Reform Plans promoted filling and draining of these areas for agricultural use. In 1986, with the incorporation of Spain to the European Union (EU, there was a sudden change of direction in these policies, which, thereafter, pursued restoring and protecting these ecosystems. This change, combined with increasing urban development and infrastructure pressures (e.g., roads, golf courses, etc., creates a conflict of uses which complicates the management of these ecosystems by local governments. This study analyzes the effectiveness of policies and management tools of important coastal wetlands at the local scale in the Valencian Community (Western Mediterranean Sea using a strengths-weaknesses-opportunities-threats (SWOT methodology. A supra-municipal model of environmental planning is proposed to enable consistent management at a regional scale. This model enhances local government’s effectiveness and it can be applied in other areas with similar problems.

  12. Bayesian inference of chemical kinetic models from proposed reactions

    KAUST Repository

    Galagali, Nikhil

    2015-02-01

    © 2014 Elsevier Ltd. Bayesian inference provides a natural framework for combining experimental data with prior knowledge to develop chemical kinetic models and quantify the associated uncertainties, not only in parameter values but also in model structure. Most existing applications of Bayesian model selection methods to chemical kinetics have been limited to comparisons among a small set of models, however. The significant computational cost of evaluating posterior model probabilities renders traditional Bayesian methods infeasible when the model space becomes large. We present a new framework for tractable Bayesian model inference and uncertainty quantification using a large number of systematically generated model hypotheses. The approach involves imposing point-mass mixture priors over rate constants and exploring the resulting posterior distribution using an adaptive Markov chain Monte Carlo method. The posterior samples are used to identify plausible models, to quantify rate constant uncertainties, and to extract key diagnostic information about model structure-such as the reactions and operating pathways most strongly supported by the data. We provide numerical demonstrations of the proposed framework by inferring kinetic models for catalytic steam and dry reforming of methane using available experimental data.

  13. Modeling and analysis of a novel planar eddy current damper

    Science.gov (United States)

    Zhang, He; Kou, Baoquan; Jin, Yinxi; Zhang, Lu; Zhang, Hailin; Li, Liyi

    2014-05-01

    In this paper, a novel 2-DOF permanent magnet planar eddy current damper is proposed, of which the stator is made of a copper plate and the mover is composed of two orthogonal 1-D permanent magnet arrays with a double sided structure. The main objective of the planar eddy current damper is to provide two orthogonal damping forces for dynamic systems like the 2-DOF high precision positioning system. Firstly, the basic structure and the operating principle of the planar damper are introduced. Secondly, the analytical model of the planar damper is established where the magnetic flux density distribution of the permanent magnet arrays is obtained by using the equivalent magnetic charge method and the image method. Then, the analytical expressions of the damping force and damping coefficient are derived. Lastly, to verify the analytical model, the finite element method (FEM) is adopted for calculating the flux density and a planar damper prototype is manufactured and thoroughly tested. The results from FEM and experiments are in good agreement with the ones from the analytical expressions indicating that the analytical model is reasonable and correct.

  14. Tacit knowledge in academia: a proposed model and measurement scale.

    Science.gov (United States)

    Leonard, Nancy; Insch, Gary S

    2005-11-01

    The authors propose a multidimensional model of tacit knowledge and develop a measure of tacit knowledge in academia. They discuss the theory and extant literature on tacit knowledge and propose a 6-factor model. Experiment 1 is a replication of a recent study of academic tacit knowledge using the scale developed and administered at an Israeli university (A. Somech & R. Bogler, 1999). The results of the replication differed from those found in the original study. For Experiment 2, the authors developed a domain-specific measure of academic tacit knowledge, the Academic Tacit Knowledge Scale (ATKS), and used this measure to explore the multidimensionality of tacit knowledge proposed in the model. The results of an exploratory factor analysis (n=142) followed by a confirmatory factor analysis (n=286) are reported. The sample for both experiments was 428 undergraduate students enrolled at a large public university in the eastern United States. Results indicated that a 5-factor model of academic tacit knowledge provided a strong fit for the data.

  15. Proposal of a new biokinetic model for niobium

    International Nuclear Information System (INIS)

    Oliveira, Roges

    2006-01-01

    There are two niobium isotopes generated in nuclear power plants: 95 Nb and 94 Nb. Workers and members of the public are subjects to intake these radionuclides in accident situation. For dose calculation purpose, it is very important to develop a model that describes in a more realistic way the kinetics of niobium inside of the human body. Presently the model adopted by ICRP (ICRP, 1989) is based on animal studies and describes the behavior of niobium in human being in a simple manner. The new model proposal describes the kinetics of the niobium from the intake into the blood until the excretion, doing this in a more realistic form and considering not only data from animals but data from human beings as well. For this objective, a workers group of a niobium extraction and processing industry exposed to stable niobium (93 Nb) in oxide insoluble form with associated uranium, was monitored for uranium and niobium determination in urinary and fecal excretion, by mass spectrometry. Based in the ratios of the niobium concentration in urinary and faecal excretion of this workers and animal data study, a new biokinetic model for niobium was proposed, with the followings modifications relative to ICRP model: a new compartment that represents muscular tissue; the fractions which are deposited into the compartment are modified; a third component in the retention equation of the bone tissue; introduction of recirculation between organs and blood. The new model was applied for a case of accidental intake and described adequately the experimental data

  16. Automatic J–A Model Parameter Tuning Algorithm for High Accuracy Inrush Current Simulation

    Directory of Open Access Journals (Sweden)

    Xishan Wen

    2017-04-01

    Full Text Available Inrush current simulation plays an important role in many tasks of the power system, such as power transformer protection. However, the accuracy of the inrush current simulation can hardly be ensured. In this paper, a Jiles–Atherton (J–A theory based model is proposed to simulate the inrush current of power transformers. The characteristics of the inrush current curve are analyzed and results show that the entire inrush current curve can be well featured by the crest value of the first two cycles. With comprehensive consideration of both of the features of the inrush current curve and the J–A parameters, an automatic J–A parameter estimation algorithm is proposed. The proposed algorithm can obtain more reasonable J–A parameters, which improve the accuracy of simulation. Experimental results have verified the efficiency of the proposed algorithm.

  17. Surface CUrrents from a Diagnostic model (SCUD): Pacific

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SCUD data product is an estimate of upper-ocean velocities computed from a diagnostic model (Surface CUrrents from a Diagnostic model). This model makes daily...

  18. Current Density and Continuity in Discretized Models

    Science.gov (United States)

    Boykin, Timothy B.; Luisier, Mathieu; Klimeck, Gerhard

    2010-01-01

    Discrete approaches have long been used in numerical modelling of physical systems in both research and teaching. Discrete versions of the Schrodinger equation employing either one or several basis functions per mesh point are often used by senior undergraduates and beginning graduate students in computational physics projects. In studying…

  19. Proposal of a probabilistic dose-response model

    International Nuclear Information System (INIS)

    Barrachina, M.

    1997-01-01

    A biologically updated dose-response model is presented as an alternative to the linear-quadratic model currently in use for cancer risk assessment. The new model is based on the probability functions for misrepair and/or unrepair of DNA lesions, in terms of the radiation damage production rate in the cell (supposedly, a stem cell) and its repair-rate constant. The model makes use, interpreting it on the basis of misrepair probabilities, of the ''dose and dose-rate effectiveness factor'' of ICRP, and provides the way for a continuous extrapolation between the high and low dose-rate regions, ratifying the ''linear non-threshold hypothesis'' as the main option. Anyhow, the model throws some doubts about the additive property of the dose. (author)

  20. Model for the resistive critical current transition in composite superconductors

    International Nuclear Information System (INIS)

    Warnes, W.H.

    1988-01-01

    Much of the research investigating technological type-II superconducting composites relies on the measurement of the resistive critical current transition. We have developed a model for the resistive transition which improves on older models by allowing for the very different nature of monofilamentary and multifilamentary composite structures. The monofilamentary model allows for axial current flow around critical current weak links in the superconducting filament. The multifilamentary model incorporates an additional radial current transfer between neighboring filaments. The development of both models is presented. It is shown that the models are useful for extracting more information from the experimental data than was formerly possible. Specific information obtainable from the experimental voltage-current characteristic includes the distribution of critical currents in the composite, the average critical current of the distribution, the range of critical currents in the composite, the field and temperature dependence of the distribution, and the fraction of the composite dissipating energy in flux flow at any current. This additional information about the distribution of critical currents may be helpful in leading toward a better understanding of flux pinning in technological superconductors. Comparison of the models with several experiments is given and shown to be in reasonable agreement. Implications of the models for the measurement of critical currents in technological composites is presented and discussed with reference to basic flux pinning studies in such composites

  1. A computational model for lower hybrid current drive

    International Nuclear Information System (INIS)

    Englade, R.C.; Bonoli, P.T.; Porkolab, M.

    1983-01-01

    A detailed simulation model for lower hybrid (LH) current drive in toroidal devices is discussed. This model accounts reasonably well for the magnitude of radio frequency (RF) current observed in the PLT and Alcator C devices. It also reproduces the experimental dependencies of RF current generation on toroidal magnetic field and has provided insights about mechanisms which may underlie the observed density limit of current drive. (author)

  2. Convective effects in a regulatory and proposed fire model

    International Nuclear Information System (INIS)

    Wix, S.D.; Hohnstreiter, G.F.

    1995-01-01

    Radiation is the dominant mode of heat transfer in large fires. However, convection can be as much as 10 to 20 percent of the total heat transfer to an object in a large fire. The current radioactive material transportation packaging regulations include convection as a mode of heat transfer in the accident condition scenario. The current International Atomic Energy Agency Safety Series 6 packaging regulation states ''the convection coefficient shall be that value which the designer can justify if the package were exposed to the specified fire''. The current Title 10, Code of Federal Regulations, Part 71 (10CFR71) packaging regulation states ''when significant, convection heat input must be included on the basis of still, ambient air at 800 degrees C (1475 degrees F)''. Two questions that can arise in an analysts mind from an examination of the packaging regulations is whether convection is significant and whether convection should be included in the design analysis of a radioactive materials transportation container. The objective of this study is to examine the convective effects on an actual radioactive materials transportation package using a regulatory and a proposed thermal boundary condition

  3. New insights from direct monitoring of turbidity currents; and a proposal for co-ordinating international efforts at a series of global "turbidity current test sites"

    Science.gov (United States)

    Talling, Peter

    2015-04-01

    Turbidity currents, and other types of submarine sediment density flow, arguably redistribute more sediment across the surface of the Earth than any other flow process. It is now over 60 years since the seminal publication of Kuenen and Migliorini (1950) in which they made the link between sequences of graded bedding and turbidity currents. The deposits of submarine sediment density flows have been described in numerous locations worldwide, and this might lead to the view that these flows are well understood. However, it is sobering to note quite how few direct measurements we have from these submarine flows in action. Sediment concentration is the critical parameter controlling such flows, yet it has never been measured directly for flows that reach and build submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical simulations or analytical models? It is proposed here that international efforts are needed for an initiative to monitor active turbidity currents at a series of 'test sites' where flows occur frequently. The flows evolve significantly, such that source to sink data are needed. We also need to directly monitor flows in different settings with variable triggering factors and flow path morphologies because their character can vary significantly. Such work should integrate numerical and physical modelling with the collection of field observations in order to understand the significance of field observations. Such an international initiative also needs to include coring of deposits to link flow processes to deposit character, because in most global locations flow behaviour must be inferred from deposits alone. Collection of seismic datasets is also crucial for understanding the larger-scale evolution and resulting architecture of these systems, and to link with studies of subsurface reservoirs. Test site datasets should thus include a wide range of data types, not just from direct flow

  4. Proposal for a race-track microtron with high peak current

    NARCIS (Netherlands)

    Ernst, G.J.; Haselhoff, E.H.; Witteman, W.J.; Botman, J.I.M.; van Genderen, W.; Hagedoorn, H.L.; van der Heide, J.A.; Kleeven, W.J.G.M.

    1989-01-01

    In order to obtain high gain in a free electron laser a high-quality electron beam with high peak current is required. It is well-known that a microtron is able to produce a high-quality beam having low emittance and small energy spread (1%). Because a circular microtron has a limited high-current

  5. Modelling and analysis of the transformer current resonance in dual active bridge converters

    DEFF Research Database (Denmark)

    Qin, Zian; Shen, Zhan; Blaabjerg, Frede

    2017-01-01

    Due to the parasitic capacitances of the transformer and inductor in Dual Active Bridge (DAB) converters, resonance happens in the transformer currents. This high frequency resonant current flowing into the full bridges will worsen their soft-switching performance and thereby reduce its efficiency....... In order to study the generation mechanism of this current resonance, the impedance of the transformer and inductor with parasitic components is modelled in this digest. Then, based on the impedance model, an approach is proposed to mitigate the current resonance. Finally, both the impedance model...

  6. Current models of positive mental health

    Directory of Open Access Journals (Sweden)

    Stanojević Dragana Z.

    2012-01-01

    Full Text Available The concept of positive mental health represents not merely the absence of mental disease but presence of high level of happiness and well-being. In this paper we mentioned shortly the earliest concept of mental health, presented by Marie Jahoda in the mid-twentieth century. After that, we described two traditions in understanding and researching of subjective well-being: hedonic and eudaimonic approach. First approach focuses on investigation of positive affects and happiness as emotional and life satisfaction as cognitive component of subjective well-being. Second tradition emphasizes potentials and competences that person develops to the highest level, in personal and social area. Both psychological and social well-being are core concept of positive mental health psychology, designated together as positive functioning. The psychological well-being comprises six dimensions: self-acceptance, positive relations with others, environmental mastery, autonomy, purpose of life and personal growth. Social well-being consists of five dimensions: social integration, social acceptance, social contribution, social actualization and social coherence. By integrating hedonic and eudaimonic well-being as well as absence of mental disease, Corey Keyes introduced concept of complete mental health. People with complete mental health have reported absence of disease during past year and presence of high level of emotional, psychological and social well-being (flourishing. People with incomplete mental health have also reported absence of mental disease but low level of positive functioning (languishing. Keyes thought there are people with complete and incomplete mental illness; both groups report presence of mental disease, but second group has high level of positive functioning. Models of positive mental health are widely used in research studies as well as in programs for prevention and promotion of mental health. .

  7. Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

    International Nuclear Information System (INIS)

    Stokes, R.H.; Minerbo, G.N.

    1985-01-01

    In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

  8. A model for electron currents near a field null

    International Nuclear Information System (INIS)

    Stark, R.A.; Miley, G.H.

    1987-01-01

    The fluid approximation is invalid near a field null, since the local electron orbit size and the magnetic scale length are comparable. To model the electron currents in this region we propose a single equation of motion describing the bulk electron dynamics. The equation applies to the plasma within one thermal orbit size of the null. The region is treated as unmagnetized; electrons are accelerated by the inductive electric field and drag on ions; damping is provided by viscosity due to electrons and collisions with ions. Through variational calculations and a particle tracking code for electrons, the size of the terms in the equation of motion have been estimated. The resulting equation of motion combines with Faraday's Law to produce a governing equation which implicitly contains the self inductive field of the electrons. This governing equation predicts that viscosity prevents complete cancellation of the ion current density by the electrons in the null region. Thus electron dynamics near the field null should not prevent the formation and deepening of field reversal using neutral-beam injection

  9. PROPOSAL OF A MODEL MANAGEMENT TO SMALL DESIGN COMPANIES

    Directory of Open Access Journals (Sweden)

    Otávio José de OLIVEIRA

    2008-11-01

    Full Text Available The main purpose of this paper is the proposition of a management model specifically developed for small building design firms, aligned with their needs and particularities. The field research was conducted with a qualitative approach through the analysis of four case studies in small building design firms acting mainly in São Paulo City. The data collection was accomplished through semi-structured interviews, direct observation and analysis of documents. The proposed model includes guidance to the management of the core processes and activities of small building design firms, such as: organizational structure; strategic planning; planning and control of design process; costs management; sales management; information systems; human resources management; services added to the design; and performance evaluation. Key-words: design firms; design process; building construction.

  10. Patent portfolio management: literature review and a proposed model.

    Science.gov (United States)

    Conegundes De Jesus, Camila Kiyomi; Salerno, Mario Sergio

    2018-05-09

    Patents and patent portfolios are gaining attention in the last decades, from the called 'pro-patent era' to the recent billionaire transactions involving patent portfolios. The field is growing in importance, both theoretically and practically and despite having substantial literature on new product development portfolio management, we have not found an article relating this theory to patent portfolios. Areas covered: The paper develops a systematic literature review on patent portfolio management to organize the evolution and tendencies of patent portfolio management, highlighting distinctive features of patent portfolio management. Interview with IP manager of three life sciences companies, including a leading multinational group provided relevant information about patent portfolio management. Expert opinion: Based on the systematic literature review on portfolio management, more specifically, on new product development portfolio theory, and interview the paper proposes the paper proposes a reference model to manage patent portfolios. The model comprises four stages aligned with the three goals of the NPD portfolio management: 1 - Linking strategy of the Company's NPD Portfolio to Patent Portfolio; 2 - Balancing the portfolio in buckets; 3 - Patent Valuation (maximizing valuation); 4 - Regularly reviewing the patent portfolio.

  11. The evaluation of doctoral thesis. A model proposal

    Directory of Open Access Journals (Sweden)

    de-Miguel, Mario

    2010-04-01

    Full Text Available The aim of this work is the development of a model that can be used as a framework for evaluators and PhD tribunal members, either during the previous administrative processing phase or at the actual exposition and viva on doctoral dissertations. To this end, once reviewed the existing literature and normative, a new proposal is laid out on the main aspects and criteria to be analysed and assessed from any given scientific work, thus introducing a tool that facilitates and specifies this work. Our model is intended to be an open proposal on which we would welcome any contribution and suggestion. El objetivo del presente trabajo es la elaboración de un modelo que pueda ser utilizado como marco de referencia por los evaluadores y miembros de tribunales de las tesis doctorales tanto en la fase previa a la tramitación administrativa como en el acto de exposición y defensa de la misma. Para ello, una vez revisada la literatura y la normativa vigente al respecto, efectuamos una propuesta sobre los principales aspectos y criterios que deben ser objeto de análisis y valoración en todo trabajo científico, y presentamos una herramienta que facilita y precisa esta tarea. Nuestro modelo constituye una propuesta abierta sobre la que esperamos aportaciones y sugerencias.

  12. Transboundary protected area proposals along the Southern Andes of Chile and Argentina: Status of current efforts

    Science.gov (United States)

    Peter Keller

    2007-01-01

    An evolving network of protected areas along the southern Andes of Chile and Argentina-the heart of Patagonia-are in various stages of evaluation and potential Transboundary Protected Area designations. This paper examines three such efforts. The first proposal is the North Andean-Patagonia Regional Eco-Corridor, which was the subject of a recent bilateral meeting...

  13. Current-voltage model of LED light sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2012-01-01

    Amplitude modulation is rarely used for dimming light-emitting diodes in polychromatic luminaires due to big color shifts caused by varying magnitude of LED driving current and nonlinear relationship between intensity of a diode and driving current. Current-voltage empirical model of light...

  14. "The Actualized Neurosurgeon": A Proposed Model of Surgical Resident Development.

    Science.gov (United States)

    Lipsman, Nir; Khan, Osaama; Kulkarni, Abhaya V

    2017-03-01

    Modern neurosurgical training is both physically and emotionally demanding, posing significant challenges, new and old, to residents as well as programs attempting to train safe, competent surgeons. Models to describe resident development, such as the Accreditation Council for Graduate Medical Education competencies and milestones, address the acquisition of specific skills but largely ignore the stresses and pressures unique to each stage of resident training. We propose an alternative model of resident development adapted from the developmental psychology literature. Our model identifies the challenges that must be met at each stage of junior, intermediate, and senior and chief residency, leading ultimately to an "actualized" neurosurgeon (i.e., one who has maximized his or her potential). Failure to overcome any 1 of these challenges can lead to specific long-lasting consequences, including regret, identity crisis, incompetence, and bitterness. In contrast, the actualized surgeon is one who has successfully acquired the virtues of hope, will, purpose, fidelity, productivity, leadership, competence, and wisdom. The actualized surgeon not only functions safely, confidently, and professionally, but also successfully navigates the challenges of residency and emerges from them having fulfilled his or her maximal potential. This developmental perspective provides an individualized description of healthy surgical development. Our model allows programs to identify the basis for residents who fail to progress, counsel residents during their training, and perhaps help identify resident candidates who are better prepared to meet the developmental challenges of residency training. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Modeling the current distribution in HTS tapes with transport current and applied magnetic field

    NARCIS (Netherlands)

    Yazawa, T.; Yazawa, Takashi; Rabbers, J.J.; Chevtchenko, O.A.; ten Haken, Bernard; ten Kate, Herman H.J.; Maeda, Hideaki

    1999-01-01

    A numerical model is developed for the current distribution in a high temperature superconducting (HTS) tape, (Bi,Pb)2Sr2 Ca2Cu3Ox-Ag, subjected to a combination of a transport current and an applied magnetic field. This analysis is based on a two-dimensional formulation of Maxwell's equations in

  16. a Proposed Benchmark Problem for Scatter Calculations in Radiographic Modelling

    Science.gov (United States)

    Jaenisch, G.-R.; Bellon, C.; Schumm, A.; Tabary, J.; Duvauchelle, Ph.

    2009-03-01

    Code Validation is a permanent concern in computer modelling, and has been addressed repeatedly in eddy current and ultrasonic modeling. A good benchmark problem is sufficiently simple to be taken into account by various codes without strong requirements on geometry representation capabilities, focuses on few or even a single aspect of the problem at hand to facilitate interpretation and to avoid that compound errors compensate themselves, yields a quantitative result and is experimentally accessible. In this paper we attempt to address code validation for one aspect of radiographic modeling, the scattered radiation prediction. Many NDT applications can not neglect scattered radiation, and the scatter calculation thus is important to faithfully simulate the inspection situation. Our benchmark problem covers the wall thickness range of 10 to 50 mm for single wall inspections, with energies ranging from 100 to 500 keV in the first stage, and up to 1 MeV with wall thicknesses up to 70 mm in the extended stage. A simple plate geometry is sufficient for this purpose, and the scatter data is compared on a photon level, without a film model, which allows for comparisons with reference codes like MCNP. We compare results of three Monte Carlo codes (McRay, Sindbad and Moderato) as well as an analytical first order scattering code (VXI), and confront them to results obtained with MCNP. The comparison with an analytical scatter model provides insights into the application domain where this kind of approach can successfully replace Monte-Carlo calculations.

  17. Biophysical models of larval dispersal in the Benguela Current ...

    African Journals Online (AJOL)

    We synthesise and update results from the suite of biophysical, larval-dispersal models developed in the Benguela Current ecosystem. Biophysical models of larval dispersal use outputs of physical hydrodynamic models as inputs to individual-based models in which biological processes acting during the larval life are ...

  18. Modeling Instruction of David Hestenes: a proposal of thematic modeling cycle and discussion of scientific literacy

    Directory of Open Access Journals (Sweden)

    Ednilson Sergio Ramalho de Souza

    2016-07-01

    Full Text Available The pedagogical work with mathematical modeling assumes investigate situations of reality. However, mental models formed from the contact with the experiential world are generally incompatible with the conceptual models. So David Hestenes supports the view that one of the biggest challenges of teaching and learning in science and mathematics is to coordinate conceptual models with mental models, which led to the elaboration of a didactic in mathematical modeling: Modeling Instruction. Our goal is to present a proposal for thematic modeling cycle drawn up in hestenesianos assumptions and discuss possibilities for scientific literacy. The main question was to know how to emerge indicators for scientific literacy for the proposed cycle. This is a bibliographic research in order to identify the available literature contributions on the subject and raise the possibility and challenges for the brazilian teaching science and mathematics. Preliminary results indicate that the proposed modeling cycle can develop indicators for scientific literacy of different natures.

  19. A New Authorization for Use of Military Force Against the Islamic State: Issues and Current Proposals

    Science.gov (United States)

    2017-02-21

    Obama in his August 2014 notifications to Congress of deployments and airstrikes in Iraq indicated his powers as Commander in Chief and Chief Executive...as well as the Khorasan Group of Al Qaeda in Syria. After these notifications, however, President Obama indicated on November 5, 2014, that he...Chairman Robert Menendez. Prior to the committee’s markup of the proposal on December 11, the committee held a hearing on December 9 with Secretary of

  20. An Analysis of Proposed and Current Regulations Concerning Lobbying Costs in Department of Defense Contracts.

    Science.gov (United States)

    1984-06-01

    a reduction in industry participation in the defense mobilization base, and a limiting of capital available for investment in producti- vity...FAR proposals, it appears that this stratgy has b-2n successful to a large degree. Thor,-, ar , how-vr, still areas where critics believe that further...appropriations. Lobbying includes but is not limited to personal discussions or conferences, advertising , sending tel- egrams, engaging in telephonic

  1. 77 FR 58510 - Proposed Information Collection; Comment Request; Current Population Survey (CPS), Annual Social...

    Science.gov (United States)

    2012-09-21

    ... various population groups. A prime statistic of interest is the classification of people in poverty and... Information Collection; Comment Request; Current Population Survey (CPS), Annual Social and Economic... conducted this supplement annually for over 50 years. The Census Bureau and the Bureau of Labor Statistics...

  2. 77 FR 10756 - Proposed Collection; Comment Request; Opinions and Perspectives About the Current Blood Donation...

    Science.gov (United States)

    2012-02-23

    ... with Men. Type of Information Collection Request: New. Need and Use of Information Collection: The... prevalence of compliance and non-compliance with the current MSM policy and assessing motivations for blood... donate blood. Frequency of Response: Once. Affected Public: Individuals. Type of Respondents: Males 18...

  3. 77 FR 35408 - Proposed Collection; Comment Request: Opinions and Perspectives About the Current Blood Donation...

    Science.gov (United States)

    2012-06-13

    ... Policy for Men Who Have Sex with Men. Type of Information Collection Request: New. Need and Use of... prevalence of compliance and non-compliance with the current MSM policy and assessing motivations for blood... donate blood. Frequency of Response: Once. Affected Public: Individuals. Type of Respondents: Males 18...

  4. Evaluation of a proposed optimization method for discrete-event simulation models

    Directory of Open Access Journals (Sweden)

    Alexandre Ferreira de Pinho

    2012-12-01

    Full Text Available Optimization methods combined with computer-based simulation have been utilized in a wide range of manufacturing applications. However, in terms of current technology, these methods exhibit low performance levels which are only able to manipulate a single decision variable at a time. Thus, the objective of this article is to evaluate a proposed optimization method for discrete-event simulation models based on genetic algorithms which exhibits more efficiency in relation to computational time when compared to software packages on the market. It should be emphasized that the variable's response quality will not be altered; that is, the proposed method will maintain the solutions' effectiveness. Thus, the study draws a comparison between the proposed method and that of a simulation instrument already available on the market and has been examined in academic literature. Conclusions are presented, confirming the proposed optimization method's efficiency.

  5. Proposal of a pedagogical model for mathematics teacher education

    Directory of Open Access Journals (Sweden)

    Alfonso Jiménez Espinosa

    2011-01-01

    Full Text Available This research-based article reflects on mathematics teacher education, and proposes a pedagogical model for this purpose, called Gradual Research Pedagogical Model (MPGI. This model considers the central curricular elements of any academic education process: student, teacher and contents, with evaluation as transversal element for analysis and feedback. The training of future teachers is constituted by three moments, each with its specific emphasis: the first is “contextualization”, which aims at having the student understand his or her new academic role, and identify and overcome his or her academic weak points, the second is “knowledge foundation”, which offers basic education in the fields of mathematics and pedagogy, as well as sensibilization towards social issues, opening up the student’s possibilities as leader and agent of change, and lastly, “knowledge immersion”, which is centered on research and the identification and study of topics and problems of the mathematical discipline as well as the pedagogical field.

  6. Databases for highway inventories. Proposal for a new model

    Energy Technology Data Exchange (ETDEWEB)

    Perez Casan, J.A.

    2016-07-01

    Database models for highway inventories are based on classical schemes for relational databases: many related tables, in which the database designer establishes, a priori, every detail that they consider relevant for inventory management. This kind of database presents several problems. First, adapting the model and its applications when new database features appear is difficult. In addition, the different needs of different sets of road inventory users are difficult to fulfil with these schemes. For example, maintenance management services, road authorities and emergency services have different needs. In addition, this kind of database cannot be adapted to new scenarios, such as other countries and regions (that may classify roads or name certain elements differently). The problem is more complex if the language used in these scenarios is not the same as that used in the database design. In addition, technicians need a long time to learn to use the database efficiently. This paper proposes a flexible, multilanguage and multipurpose database model, which gives an effective and simple solution to the aforementioned problems. (Author)

  7. Corporate Social Responsibility And Islamic Business Organizations: A Proposed Model

    Directory of Open Access Journals (Sweden)

    Rusnah Muhamad

    2008-01-01

    Full Text Available The issue of corporate social responsibility (CSR has been of growing concern among business communities in recent years. Various corporate leaders maintain that business is considered to contribute fully to the society if it is effi cient, profi table and socially responsible. Islam is considered as addin (a way of life, thus, providing comprehensive guidelines in every aspects of the believers’ life. It is the aim of this paper to propose an Islamic model of corporate social responsibility based on human relationships with the God (hablun min’Allah; with other fellow human being (hablun min’an-nas and with the environment.Keywords : Corporate Social Responsibility, Islamic Business Organization

  8. PTSD's latent structure in Malaysian tsunami victims: assessing the newly proposed Dysphoric Arousal model.

    Science.gov (United States)

    Armour, Cherie; Raudzah Ghazali, Siti; Elklit, Ask

    2013-03-30

    The underlying latent structure of Posttraumatic Stress Disorder (PTSD) is widely researched. However, despite a plethora of factor analytic studies, no single model has consistently been shown as superior to alternative models. The two most often supported models are the Emotional Numbing and the Dysphoria models. However, a recently proposed five-factor Dysphoric Arousal model has been gathering support over and above existing models. Data for the current study were gathered from Malaysian Tsunami survivors (N=250). Three competing models (Emotional Numbing/Dysphoria/Dysphoric Arousal) were specified and estimated using Confirmatory Factor Analysis (CFA). The Dysphoria model provided superior fit to the data compared to the Emotional Numbing model. However, using chi-square difference tests, the Dysphoric Arousal model showed a superior fit compared to both the Emotional Numbing and Dysphoria models. In conclusion, the current results suggest that the Dysphoric Arousal model better represents PTSD's latent structure and that items measuring sleeping difficulties, irritability/anger and concentration difficulties form a separate, unique PTSD factor. These results are discussed in relation to the role of Hyperarousal in PTSD's on-going symptom maintenance and in relation to the DSM-5. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Modelling of the ring current in Saturn's magnetosphere

    Directory of Open Access Journals (Sweden)

    G. Giampieri

    2004-01-01

    Full Text Available The existence of a ring current inside Saturn's magnetosphere was first suggested by Smith et al. (1980 and Ness et al. (1981, 1982, in order to explain various features in the magnetic field observations from the Pioneer 11 and Voyager 1 and 2 spacecraft. Connerney et al. (1983 formalized the equatorial current model, based on previous modelling work of Jupiter's current sheet and estimated its parameters from the two Voyager data sets. Here, we investigate the model further, by reconsidering the data from the two Voyager spacecraft, as well as including the Pioneer 11 flyby data set. First, we obtain, in closed form, an analytic expression for the magnetic field produced by the ring current. We then fit the model to the external field, that is the difference between the observed field and the internal magnetic field, considering all the available data. In general, through our global fit we obtain more accurate parameters, compared to previous models. We point out differences between the model's parameters for the three flybys, and also investigate possible deviations from the axial and planar symmetries assumed in the model. We conclude that an accurate modelling of the Saturnian disk current will require taking into account both of the temporal variations related to the condition of the magnetosphere, as well as non-axisymmetric contributions due to local time effects. Key words. Magnetospheric physics (current systems; planetary magnetospheres; plasma sheet

  10. Methodology Using MELCOR Code to Model Proposed Hazard Scenario

    Energy Technology Data Exchange (ETDEWEB)

    Gavin Hawkley

    2010-07-01

    This study demonstrates a methodology for using the MELCOR code to model a proposed hazard scenario within a building containing radioactive powder, and the subsequent evaluation of a leak path factor (LPF) (or the amount of respirable material which that escapes a facility into the outside environment), implicit in the scenario. This LPF evaluation will analyzes the basis and applicability of an assumed standard multiplication of 0.5 × 0.5 (in which 0.5 represents the amount of material assumed to leave one area and enter another), for calculating an LPF value. The outside release is dependsent upon the ventilation/filtration system, both filtered and un-filtered, and from other pathways from the building, such as doorways (, both open and closed). This study is presents ed to show how the multiple leak path factorsLPFs from the interior building can be evaluated in a combinatory process in which a total leak path factorLPF is calculated, thus addressing the assumed multiplication, and allowing for the designation and assessment of a respirable source term (ST) for later consequence analysis, in which: the propagation of material released into the environmental atmosphere can be modeled and the dose received by a receptor placed downwind can be estimated and the distance adjusted to maintains such exposures as low as reasonably achievableALARA.. Also, this study will briefly addresses particle characteristics thatwhich affect atmospheric particle dispersion, and compares this dispersion with leak path factorLPF methodology.

  11. Micromagnetic modeling of critical current oscillations in magnetic Josephson junctions

    NARCIS (Netherlands)

    golovchanskiy, I.A.; Bol'ginov, V.V.; Stolyarov, V.S.; Abramov, N.N.; Ben Hamida, A.; Emelyanova, O.V.; Stolyarov, B.S.; Kupriyanov, M..Y.; Golubov, Alexandre Avraamovitch; Ryazanov, V.V.

    2016-01-01

    In this work we propose and explore an effective numerical approach for investigation of critical current dependence on applied magnetic field for magnetic Josephson junctions with in-plane magnetization orientation. This approach is based on micromagnetic simulation of the magnetization reversal

  12. Energy infrastructure modeling for the oil sands industry: Current situation

    International Nuclear Information System (INIS)

    Lazzaroni, Edoardo Filippo; Elsholkami, Mohamed; Arbiv, Itai; Martelli, Emanuele; Elkamel, Ali; Fowler, Michael

    2016-01-01

    Highlights: • A simulation-based modelling of energy demands of oil sands operations is proposed. • Aspen simulations used to simulate delayed coking-based upgrading of bitumen. • The energy infrastructure is simulated using Aspen Plus achieving self-sufficiency. • Various scenarios affecting energy demand intensities are investigated. • Energy and CO_2 emission intensities of integrated SAGD/upgrading are estimated. - Abstract: In this study, the total energy requirements associated with the production of bitumen from oil sands and its upgrading to synthetic crude oil (SCO) are modeled and quantified. The production scheme considered is based on the commercially applied steam assisted gravity drainage (SAGD) for bitumen extraction and delayed coking for bitumen upgrading. In addition, the model quantifies the greenhouse gas (GHG) emissions associated with the production of energy required for these operations from technologies utilized in the currently existing oil sands energy infrastructure. The model is based on fundamental engineering principles, and Aspen HYSYS and Aspen Plus simulations. The energy demand results are expressed in terms of heat, power, hydrogen, and process fuel consumption rates for SAGD extraction and bitumen upgrading. Based on the model’s output, a range of overall energy and emission intensity factors are estimated for a bitumen production rate of 112,500 BPD (or 93,272 BPD of SCO), which were determined to be 262.5–368.5 MJ/GJ_S_C_O and 14.17–19.84 gCO_2/MJ_S_C_O, respectively. The results of the model indicate that the majority of GHG emissions are generated during SAGD extraction (up to 60% of total emissions) due to the combustion of natural gas for steam production, and the steam-to-oil ratio is a major parameter affecting total GHG emissions. The developed model can be utilized as a tool to predict the energy demand requirements for integrated SAGD/upgrading projects under different operating conditions, and

  13. Model for ICRF fast wave current drive in self-consistent MHD equilibria

    International Nuclear Information System (INIS)

    Bonoli, P.T.; Englade, R.C.; Porkolab, M.; Fenstermacher, M.E.

    1993-01-01

    Recently, a model for fast wave current drive in the ion cyclotron radio frequency (ICRF) range was incorporated into the current drive and MHD equilibrium code ACCOME. The ACCOME model combines a free boundary solution of the Grad Shafranov equation with the calculation of driven currents due to neutral beam injection, lower hybrid (LH) waves, bootstrap effects, and ICRF fast waves. The equilibrium and current drive packages iterate between each other to obtain an MHD equilibrium which is consistent with the profiles of driven current density. The ICRF current drive package combines a toroidal full-wave code (FISIC) with a parameterization of the current drive efficiency obtained from an adjoint solution of the Fokker Planck equation. The electron absorption calculation in the full-wave code properly accounts for the combined effects of electron Landau damping (ELD) and transit time magnetic pumping (TTMP), assuming a Maxwellian (or bi-Maxwellian) electron distribution function. Furthermore, the current drive efficiency includes the effects of particle trapping, momentum conserving corrections to the background Fokker Planck collision operator, and toroidally induced variations in the parallel wavenumbers of the injected ICRF waves. This model has been used to carry out detailed studies of advanced physics scenarios in the proposed Tokamak Physics Experiment (TPX). Results are shown, for example, which demonstrate the possibility of achieving stable equilibria at high beta and high bootstrap current fraction in TPX. Model results are also shown for the proposed ITER device

  14. QAM: PROPOSED MODEL FOR QUALITY ASSURANCE IN CBSS

    Directory of Open Access Journals (Sweden)

    Latika Kharb

    2015-08-01

    Full Text Available Component-based software engineering (CBSE / Component-Based Development (CBD lays emphasis on decomposition of the engineered systems into functional or logical components with well-defined interfaces used for communication across the components. Component-based software development approach is based on the idea to develop software systems by selecting appropriate off-the-shelf components and then to assemble them with a well-defined software architecture. Because the new software development paradigm is much different from the traditional approach, quality assurance for component-based software development is a new topic in the software engineering research community. Because component-based software systems are developed on an underlying process different from that of the traditional software, their quality assurance model should address both the process of components and the process of the overall system. Quality assurance for component-based software systems during the life cycle is used to analyze the components for achievement of high quality component-based software systems. Although some Quality assurance techniques and component based approach to software engineering have been studied, there is still no clear and well-defined standard or guidelines for component-based software systems. Therefore, identification of the quality assurance characteristics, quality assurance models, quality assurance tools and quality assurance metrics, are under urgent need. As a major contribution in this paper, I have proposed QAM: Quality Assurance Model for component-based software development, which covers component requirement analysis, component development, component certification, component architecture design, integration, testing, and maintenance.

  15. Family medicine practice in Saudi Arabia: The current situation and Proposed Strategic Directions Plan 2020.

    Science.gov (United States)

    Al-Khaldi, Yahia M; Al-Ghamdi, Essam A; Al-Mogbil, Tariq I; Al-Khashan, Hesham I

    2017-01-01

    The objectives of this study were to assess the current situation of the teaching and training of undergraduate and postgraduate programs in family medicine in KSA, assess the current practice of family medicine, and draw a roadmap to achieve Saudi vision 2020. This study was conducted with the support and collaboration of the Primary Health Care Department of the Ministry of Health, Saudi Arabia, and World Health Organization (EMRO) in November 2015. Based on the literature review of previous studies conducted for similar purposes, relevant questionnaires were developed. These consisted of four forms, each of which was directed at a different authority to achieve the above-mentioned objectives. Data of all questionnaires were coded, entered, and analyzed using SPSS version 16. There are 2282 primary health-care centers (PHCCs), 60% of which are in rural areas. More than half of the PHCCs have a laboratory and more than one-third have a Radiology Department. Out of the 6107 physicians, 636 are family physicians (10%). All medical colleges have a family medicine department with a total staff of 170 medical teachers. Thirteen departments run family medicine courses of 4-8 weeks' duration for students. Fourteen colleges have internship programs in family medicine and four colleges have postgraduate centers for family medicine (27%). There are 95 training centers for Saudi Board (Saudi Board of Family Medicine [SBFM]) and 68 centers for Saudi Diploma (Saudi Diploma of Family Medicine [SDFM]). The total number of trainers was 241, while the total trainees were 756 in SBFM and 137 in SDFM. This survey showed that there is a shortage of qualified family physicians in all health sectors in Saudi Arabia as a result of the lack of a strategic plan for the training of family physicians. A national strategic plan with specific objectives and an explicit budget are necessary to deal with this shortage and improve the quality of health-care services at PHCCs.

  16. Analytical drift-current threshold voltage model of long-channel double-gate MOSFETs

    International Nuclear Information System (INIS)

    Shih, Chun-Hsing; Wang, Jhong-Sheng

    2009-01-01

    This paper presents a new, physical threshold voltage model to solve the ambiguity in determining the threshold voltage of double-gate (DG) MOSFETs. To avoid the difficulties of the conventional 2ψ B model in nearly undoped DG MOSFETs, this study proposes to define the on–off switching based on the actual roles of the drift and diffusion components in the total drain current. The drift current strongly enhances beyond the threshold voltage, while the diffusion current plays a major role in the subthreshold. The threshold voltage is defined as the drift component that exceeds the diffusion counterpart. From the solutions of Poisson's equation, the drift and diffusion currents of DG MOSFETs are separately formulated to derive the analytical expressions of the threshold voltage and associated threshold current. This model provides a comprehensive description of the switching behavior of DG MOSFET devices, and offers a physical onset threshold current to determine the threshold voltage in practical extraction

  17. Temperature in non-equilibrium states: a review of open problems and current proposals

    International Nuclear Information System (INIS)

    Casas-Vazquez, J; Jou, D

    2003-01-01

    The conceptual problems arising in the definition and measurement of temperature in non-equilibrium states are discussed in this paper in situations where the local-equilibrium hypothesis is no longer satisfactory. This is a necessary and urgent discussion because of the increasing interest in thermodynamic theories beyond local equilibrium, in computer simulations, in non-linear statistical mechanics, in new experiments, and in technological applications of nanoscale systems and material sciences. First, we briefly review the concept of temperature from the perspectives of equilibrium thermodynamics and statistical mechanics. Afterwards, we explore which of the equilibrium concepts may be extrapolated beyond local equilibrium and which of them should be modified, then we review several attempts to define temperature in non-equilibrium situations from macroscopic and microscopic bases. A wide review of proposals is offered on effective non-equilibrium temperatures and their application to ideal and real gases, electromagnetic radiation, nuclear collisions, granular systems, glasses, sheared fluids, amorphous semiconductors and turbulent fluids. The consistency between the different relativistic transformation laws for temperature is discussed in the new light gained from this perspective. A wide bibliography is provided in order to foster further research in this field

  18. Electromagnetic modeling method for eddy current signal analysis

    International Nuclear Information System (INIS)

    Lee, D. H.; Jung, H. K.; Cheong, Y. M.; Lee, Y. S.; Huh, H.; Yang, D. J.

    2004-10-01

    An electromagnetic modeling method for eddy current signal analysis is necessary before an experiment is performed. Electromagnetic modeling methods consists of the analytical method and the numerical method. Also, the numerical methods can be divided by Finite Element Method(FEM), Boundary Element Method(BEM) and Volume Integral Method(VIM). Each modeling method has some merits and demerits. Therefore, the suitable modeling method can be chosen by considering the characteristics of each modeling. This report explains the principle and application of each modeling method and shows the comparison modeling programs

  19. Current algebra of classical non-linear sigma models

    International Nuclear Information System (INIS)

    Forger, M.; Laartz, J.; Schaeper, U.

    1992-01-01

    The current algebra of classical non-linear sigma models on arbitrary Riemannian manifolds is analyzed. It is found that introducing, in addition to the Noether current j μ associated with the global symmetry of the theory, a composite scalar field j, the algebra closes under Poisson brackets. (orig.)

  20. Cardiac magnetic source imaging based on current multipole model

    International Nuclear Information System (INIS)

    Tang Fa-Kuan; Wang Qian; Hua Ning; Lu Hong; Tang Xue-Zheng; Ma Ping

    2011-01-01

    It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution. Then the minimum-norm least-squares (MNLS) method, the optimal weighted pseudoinverse method (OWPIM), and the optimal constrained linear inverse method (OCLIM) are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides, two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared. (general)

  1. Current Capabilities, Requirements and a Proposed Strategy for Interdependency Analysis in the UK

    Science.gov (United States)

    Bloomfield, Robin; Chozos, Nick; Salako, Kizito

    The UK government recently commissioned a research study to identify the state-of-the-art in Critical Infrastructure modelling and analysis, and the government/industry requirements for such tools and services. This study (Cetifs) concluded with a strategy aiming to bridge the gaps between the capabilities and requirements, which would establish interdependency analysis as a commercially viable service in the near future. This paper presents the findings of this study that was carried out by CSR, City University London, Adelard LLP, a safety/security consultancy and Cranfield University, defense academy of the UK.

  2. Current algebra of WZNW models at and away from criticality

    International Nuclear Information System (INIS)

    Abdalla, E.; Forger, M.

    1992-01-01

    In this paper, the authors derive the current algebra of principal chiral models with a Wess-Zumino term. At the critical coupling where the model becomes conformally invariant (Wess-Zumino-Novikov-Witten theory), this algebra reduces to two commuting Kac-Moody algebras, while in the limit where the coupling constant is taken to zero (ordinary chiral model), we recover the current algebra of that model. In this way, the latter is explicitly realized as a deformation of the former, with the coupling constant as the deformation parameter

  3. Pediatric Renal Transplantation: Focus on Current Transition Care and Proposal of the "RISE to Transition" Protocol.

    Science.gov (United States)

    Raina, Rupesh; Wang, Joseph; Krishnappa, Vinod; Ferris, Maria

    2018-01-16

    The transition from pediatric to adult medical services is an important time in the life of an adolescent or young adult with a renal transplant. Failure of proper transition can lead to medical non-adherence and subsequent loss of graft and/or return to dialysis. The aim of this study was to conduct a systematic review and survey to assess the challenges and existing practices in transition of renal transplant recipient children to adult services, and to develop a transition protocol. We conducted a literature review and performed a survey of pediatric nephrologists across the United States to examine the current state of transition care. A structured transition protocol was developed based on these results. Our literature review revealed that a transition program has a positive impact on decline in renal function and acute rejection episodes, and may improve long-term graft outcomes in pediatric kidney transplant patients. With a response rate of 40% (60/150) from nephrologists in 56% (49/87) of centers, our survey shows inconsistent use of validated tools despite their availability, inefficient communication between teams, and lack of use of dedicated clinics. To address these issues, we developed the "RISE to Transition" protocol, which relies on 4 competency areas: Recognition, Insight, Self-reliance, and Establishment of healthy habits. The transition program decreases acute graft rejection episodes, and the main challenges in transition care are the communication gap between health care providers and inconsistent use of transition tools. Our RISE to transition protocol incorporates transition tools, defines personnel, and aims to improve communication between teams.

  4. Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

    Directory of Open Access Journals (Sweden)

    Zhijian Fang

    2018-03-01

    Full Text Available In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feedback inner loop is proposed to increase the control system damping, improving dynamic performance. The modeling and design methodology for the LLC resonant converter are also presented in this paper. A frequency analysis is conducted to verify the accuracy of the simplified model. Finally, a 200 W LLC resonant converter prototype is built to verify the effectiveness of the proposed control strategy. Compared to a traditional single-loop controller, the settling time and voltage droop were reduced from 10.8 ms to 8.6 ms and from 6.8 V to 4.8 V, respectively, using the proposed control strategy.

  5. An appraisal of current regulations and recommendations in relation to proposals for the use of X-ray optics equipment

    International Nuclear Information System (INIS)

    Weatherley, E.G.

    1984-01-01

    Current regulatory requirements for the use of x-ray optics equipment in factories are compared with the 19-year-old Guidance Notes for their use in research and teaching establishments. The difficulties in drafting new legislation to cater for both areas of use are discussed and the proposed regulations and approved code of practice having a direct bearing on x-ray optics equipment are reviewed. Comment is made concerning the proposed Health and Safety Executive document, ''Radiation Safety in the use of X-ray Optics Equipment, which will give practical advice and guidance on cost effective methods of achieving the regulatory objectives. The costs involved are unlikely to be significant for the majority of users and implementation of the proposed legislation should not restrict the use of x-ray optics equipment. (author)

  6. Combined kinetic and transport modeling of radiofrequency current drive

    International Nuclear Information System (INIS)

    Dumont, R.; Giruzzi, G.; Barbato, E.

    2000-07-01

    A numerical model for predictive simulations of radiofrequency current drive in magnetically confined plasmas is developed. It includes the minimum requirements for a self consistent description of such regimes, i.e., a 3-D ,kinetic equation for the electron distribution function, 1-D heat and current transport equations, and resonant coupling between velocity space and configuration space dynamics, through suitable wave propagation equations. The model finds its full application in predictive studies of complex current profile control scenarios in tokamaks, aiming at the establishment of internal transport barriers by the simultaneous use of various radiofrequency current drive methods. The basic properties of this non-linear numerical system are investigated and illustrated by simulations applied to reversed magnetic shear regimes obtained by Lower Hybrid and Electron Cyclotron current drive for parameters typical of the Tore Supra tokamak. (authors)

  7. Modelling of helical current filaments induced by LHW on EAST

    Energy Technology Data Exchange (ETDEWEB)

    Rack, Michael; Denner, Peter; Liang, Yunfeng [Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, D-52425 Juelich (Germany); Zeng, Long [Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, D-52425 Juelich (Germany); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Gong, Xianzu; Gan, Kaifu; Wang, Liang; Liu, Fukun; Qian, Jinping; Shen, Biao; Li, Jiangang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Gauthier, Eric [Association EURATOM-CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Collaboration: the EAST Team

    2013-07-01

    Helical radiation belts have been observed in the scrape-off layer (SOL) of the plasma during the application of lower hybrid wave (LHW) heating at the superconducting tokamak EAST. Modelled SOL field lines, starting in-front of the LHW antennas, show agreement in position and pitch angle to the experimental observed radiation belts. A splitting of the strike-line can be observed on the outer divertor plates during the application of LHW heating. Agreement in the comparison of the Mirnov coil signals and a modelled electric current flow along these SOL field lines was found. A lower hybrid current drive can induce such an electric current flow near the plasma edge. This electric current flow causes a change of the plasma topology which could result in the splitting of the strike-line as known from the application of resonant magnetic perturbation fields. Comparisons of modelled footprint structures and experimental observed heat load patterns in the divertor region are discussed.

  8. Storm-time ring current: model-dependent results

    Directory of Open Access Journals (Sweden)

    N. Yu. Ganushkina

    2012-01-01

    Full Text Available The main point of the paper is to investigate how much the modeled ring current depends on the representations of magnetic and electric fields and boundary conditions used in simulations. Two storm events, one moderate (SymH minimum of −120 nT on 6–7 November 1997 and one intense (SymH minimum of −230 nT on 21–22 October 1999, are modeled. A rather simple ring current model is employed, namely, the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM, in order to make the results most evident. Four different magnetic field and two electric field representations and four boundary conditions are used. We find that different combinations of the magnetic and electric field configurations and boundary conditions result in very different modeled ring current, and, therefore, the physical conclusions based on simulation results can differ significantly. A time-dependent boundary outside of 6.6 RE gives a possibility to take into account the particles in the transition region (between dipole and stretched field lines forming partial ring current and near-Earth tail current in that region. Calculating the model SymH* by Biot-Savart's law instead of the widely used Dessler-Parker-Sckopke (DPS relation gives larger and more realistic values, since the currents are calculated in the regions with nondipolar magnetic field. Therefore, the boundary location and the method of SymH* calculation are of key importance for ring current data-model comparisons to be correctly interpreted.

  9. General Potential-Current Model and Validation for Electrocoagulation

    International Nuclear Information System (INIS)

    Dubrawski, Kristian L.; Du, Codey; Mohseni, Madjid

    2014-01-01

    A model relating potential and current in continuous parallel plate iron electrocoagulation (EC) was developed for application in drinking water treatment. The general model can be applied to any EC parallel plate system relying only on geometric and tabulated input variables without the need of system-specific experimentally derived constants. For the theoretical model, the anode and cathode were vertically divided into n equipotential segments in a single pass, upflow, and adiabatic EC reactor. Potential and energy balances were simultaneously solved at each vertical segment, which included the contribution of ionic concentrations, solution temperature and conductivity, cathodic hydrogen flux, and gas/liquid ratio. We experimentally validated the numerical model with a vertical upflow EC reactor using a 24 cm height 99.99% pure iron anode divided into twelve 2 cm segments. Individual experimental currents from each segment were summed to determine total current, and compared with the theoretically derived value. Several key variables were studied to determine their impact on model accuracy: solute type, solute concentration, current density, flow rate, inter-electrode gap, and electrode surface condition. Model results were in good agreement with experimental values at cell potentials of 2-20 V (corresponding to a current density range of approximately 50-800 A/m 2 ), with mean relative deviation of 9% for low flow rate, narrow electrode gap, polished electrodes, and 150 mg/L NaCl. Highest deviation occurred with a large electrode gap, unpolished electrodes, and Na 2 SO 4 electrolyte, due to parasitic H 2 O oxidation and less than unity current efficiency. This is the first general model which can be applied to any parallel plate EC system for accurate electrochemical voltage or current prediction

  10. A Neuron Model Based Ultralow Current Sensor System for Bioapplications

    Directory of Open Access Journals (Sweden)

    A. K. M. Arifuzzman

    2016-01-01

    Full Text Available An ultralow current sensor system based on the Izhikevich neuron model is presented in this paper. The Izhikevich neuron model has been used for its superior computational efficiency and greater biological plausibility over other well-known neuron spiking models. Of the many biological neuron spiking features, regular spiking, chattering, and neostriatal spiny projection spiking have been reproduced by adjusting the parameters associated with the model at hand. This paper also presents a modified interpretation of the regular spiking feature in which the firing pattern is similar to that of the regular spiking but with improved dynamic range offering. The sensor current ranges between 2 pA and 8 nA and exhibits linearity in the range of 0.9665 to 0.9989 for different spiking features. The efficacy of the sensor system in detecting low amount of current along with its high linearity attribute makes it very suitable for biomedical applications.

  11. Calculation of DC Arc Plasma Torch Voltage- Current Characteristics Based on Steebeck Model

    International Nuclear Information System (INIS)

    Gnedenko, V.G.; Ivanov, A.A.; Pereslavtsev, A.V.; Tresviatsky, S.S.

    2006-01-01

    The work is devoted to the problem of the determination of plasma torches parameters and power sources parameters (working voltage and current of plasma torch) at the predesigning stage. The sequence of calculation of voltage-current characteristics of DC arc plasma torch is proposed. It is shown that the simple Steenbeck model of arc discharge in cylindrical channel makes it possible to carry out this calculation. The results of the calculation are confirmed by the experiments

  12. Regression analysis of informative current status data with the additive hazards model.

    Science.gov (United States)

    Zhao, Shishun; Hu, Tao; Ma, Ling; Wang, Peijie; Sun, Jianguo

    2015-04-01

    This paper discusses regression analysis of current status failure time data arising from the additive hazards model in the presence of informative censoring. Many methods have been developed for regression analysis of current status data under various regression models if the censoring is noninformative, and also there exists a large literature on parametric analysis of informative current status data in the context of tumorgenicity experiments. In this paper, a semiparametric maximum likelihood estimation procedure is presented and in the method, the copula model is employed to describe the relationship between the failure time of interest and the censoring time. Furthermore, I-splines are used to approximate the nonparametric functions involved and the asymptotic consistency and normality of the proposed estimators are established. A simulation study is conducted and indicates that the proposed approach works well for practical situations. An illustrative example is also provided.

  13. Model for an irreversible bias current in the superconducting qubit measurement process

    International Nuclear Information System (INIS)

    Hutchinson, G. D.; Williams, D. A.; Holmes, C. A.; Stace, T. M.; Spiller, T. P.; Barrett, S. D.; Milburn, G. J.; Hasko, D. G.

    2006-01-01

    The superconducting charge-phase ''quantronium'' qubit is considered in order to develop a model for the measurement process used in the experiment of Vion et al. [Science 296, 886 (2002)]. For this model we propose a method for including the bias current in the readout process in a fundamentally irreversible way, which to first order is approximated by the Josephson junction tilted-washboard potential phenomenology. The decohering bias current is introduced in the form of a Lindblad operator and the Wigner function for the current-biased readout Josephson junction is derived and analyzed. During the readout current pulse used in the quantronium experiment we find that the coherence of the qubit initially prepared in a symmetric superposition state is lost at a time of 0.2 ns after the bias current pulse has been applied, a time scale that is much shorter than the experimental readout time. Additionally we look at the effect of Johnson-Nyquist noise with zero mean from the current source during the qubit manipulation and show that the decoherence due to the irreversible bias current description is an order of magnitude smaller than that found through adding noise to the reversible tilted-washboard potential model. Our irreversible bias current model is also applicable to persistent-current-based qubits where the state is measured according to its flux via a small-inductance direct-current superconducting quantum interference device

  14. Currents, charges, and canonical structure of pseudodual chiral models

    International Nuclear Information System (INIS)

    Curtright, T.; Zachos, C.

    1994-01-01

    We discuss the pseudodual chiral model to illustrate a class of two-dimensional theories which have an infinite number of conservation laws but allow particle production, at variance with naive expectations. We describe the symmetries of the pseudodual model, both local and nonlocal, as transmutations of the symmetries of the usual chiral model. We refine the conventional algorithm to more efficiently produce the nonlocal symmetries of the model, and we discuss the complete local current algebra for the pseudodual theory. We also exhibit the canonical transformation which connects the usual chiral model to its fully equivalent dual, further distinguishing the pseudodual theory

  15. Meson exchange current (MEC) models in neutrino interaction generators

    International Nuclear Information System (INIS)

    Katori, Teppei

    2015-01-01

    Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent program in neutrino interaction physics for current and future oscillation experiments. Such processes are believed to be responsible for the event excesses observed by recent neutrino experiments. The 2p-2h effect is dominated by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission from the primary vertex, instead of a single nucleon emission from the charged-current quasi-elastic (CCQE) interaction. Current and future high resolution experiments can potentially nail down this effect. For this reason, there are world wide efforts to model and implement this process in neutrino interaction simulations. In these proceedings, I would like to describe how this channel is modeled in neutrino interaction generators

  16. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    Energy Technology Data Exchange (ETDEWEB)

    Venkattraman, Ayyaswamy [Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-11-15

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission.

  17. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    International Nuclear Information System (INIS)

    Venkattraman, Ayyaswamy

    2013-01-01

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission

  18. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  19. Dynamic modelling of tearing mode stabilization by RF current drive

    International Nuclear Information System (INIS)

    Giruzzi, G.; Zabiego, M.; Gianakon, T.A.; Garbet, X.; Bernabei, S.

    1998-01-01

    The theory of tearing mode stabilization in toroidal plasmas by RF-driven currents that are modulated in phase with the island rotation is investigated. A time scale analysis of the phenomena involved indicates that transient effects, such as finite time response of the driven currents, island rotation during the power pulses, and the inductive response of the plasma, are intrinsically important. A dynamic model of such effects is developed, based on a 3-D Fokker-Planck code coupled to both the electric field diffusion and the island evolution equations. Extensive applications to both Electron Cyclotron and Lower Hybrid current drive in ITER are presented. (author)

  20. Development of three dimensional ocean current model for coastal region

    International Nuclear Information System (INIS)

    Kobayashi, Takuya

    1999-12-01

    In order to study the migration behavior of radionuclides released into a coastal region around Japan, Princeton Ocean Model (POM) was introduced. This three-dimensional ocean current model was modified to be applied for oceanic simulations around Japan. This report describes the governing equations, numerical methods and model improvements. In addition, database system which is utilized for calculations and visualization system for graphical outputs are also described. Model simulation was carried out at off the area of Shimokita. Aomori-ken, Japan to investigate the effects of the boundary conditions on simulated results. (author)

  1. One-Dimensional Modelling of Marine Current Turbine Runaway Behaviour

    Directory of Open Access Journals (Sweden)

    Staffan Lundin

    2016-04-01

    Full Text Available If a turbine loses its electrical load, it will rotate freely and increase speed, eventually achieving that rotational speed which produces zero net torque. This is known as a runaway situation. Unlike many other types of turbine, a marine current turbine will typically overshoot the final runaway speed before slowing down and settling at the runaway speed. Since the hydrodynamic forces acting on the turbine are dependent on rotational speed and acceleration, turbine behaviour during runaway becomes important for load analyses during turbine design. In this article, we consider analytical and numerical models of marine current turbine runaway behaviour in one dimension. The analytical model is found not to capture the overshoot phenomenon, while still providing useful estimates of acceleration at the onset of runaway. The numerical model incorporates turbine wake build-up and predicts a rotational speed overshoot. The predictions of the models are compared against measurements of runaway of a marine current turbine. The models are also used to recreate previously-published results for a tidal turbine and applied to a wind turbine. It is found that both models provide reasonable estimates of maximum accelerations. The numerical model is found to capture the speed overshoot well.

  2. a Proposal for Generalization of 3d Models

    Science.gov (United States)

    Uyar, A.; Ulugtekin, N. N.

    2017-11-01

    In recent years, 3D models have been created of many cities around the world. Most of the 3D city models have been introduced as completely graphic or geometric models, and the semantic and topographic aspects of the models have been neglected. In order to use 3D city models beyond the task, a generalization is necessary. CityGML is an open data model and XML-based format for the storage and exchange of virtual 3D city models. Level of Details (LoD) which is an important concept for 3D modelling, can be defined as outlined degree or prior representation of real-world objects. The paper aim is first describes some requirements of 3D model generalization, then presents problems and approaches that have been developed in recent years. In conclude the paper will be a summary and outlook on problems and future work.

  3. Numeral eddy current sensor modelling based on genetic neural network

    International Nuclear Information System (INIS)

    Yu Along

    2008-01-01

    This paper presents a method used to the numeral eddy current sensor modelling based on the genetic neural network to settle its nonlinear problem. The principle and algorithms of genetic neural network are introduced. In this method, the nonlinear model parameters of the numeral eddy current sensor are optimized by genetic neural network (GNN) according to measurement data. So the method remains both the global searching ability of genetic algorithm and the good local searching ability of neural network. The nonlinear model has the advantages of strong robustness, on-line modelling and high precision. The maximum nonlinearity error can be reduced to 0.037% by using GNN. However, the maximum nonlinearity error is 0.075% using the least square method

  4. Numerical modeling of 3D halo current path in ITER structures

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Paolo; Marconato, Nicolò; Furno Palumbo, Maurizio; Peruzzo, Simone [Consorzio RFX, EURATOM-ENEA Association, C.so Stati Uniti 4, 35127 Padova (Italy); Specogna, Ruben, E-mail: ruben.specogna@uniud.it [DIEGM, Università di Udine, Via delle Scienze, 208, 33100 Udine (Italy); Albanese, Raffaele; Rubinacci, Guglielmo; Ventre, Salvatore; Villone, Fabio [Consorzio CREATE, EURATOM-ENEA Association, Via Claudio 21, 80125 Napoli (Italy)

    2013-10-15

    Highlights: ► Two numerical codes for the evaluation of halo currents in 3D structures are presented. ► A simplified plasma model is adopted to provide the input (halo current injected into the FW). ► Two representative test cases of ITER symmetric and asymmetric VDEs have been analyzed. ► The proposed approaches provide results in excellent agreement for both cases. -- Abstract: Disruptions represent one of the main concerns for Tokamak operation, especially in view of fusion reactors, or experimental test reactors, due to the electro-mechanical loads induced by halo and eddy currents. The development of a predictive tool which allows to estimate the magnitude and spatial distribution of the halo current forces is of paramount importance in order to ensure robust vessel and in-vessel component design. With this aim, two numerical codes (CARIDDI, CAFE) have been developed, which allow to calculate the halo current path (resistive distribution) in the passive structures surrounding the plasma. The former is based on an integral formulation for the eddy currents problem particularized to the static case; the latter implements a pair of 3D FEM complementary formulations for the solution of the steady-state current conduction problem. A simplified plasma model is adopted to provide the inputs (halo current injected into the first wall). Two representative test cases (ITER symmetric and asymmetric VDEs) have been selected to cross check the results of the proposed approaches.

  5. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    Science.gov (United States)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  6. Ring current models for acetylene and ethylene molecules

    International Nuclear Information System (INIS)

    Pelloni, Stefano; Lazzeretti, Paolo

    2009-01-01

    Spatial models of the current density vector field, induced in the electronic cloud of the acetylene and ethylene molecules by a uniform, time-independent magnetic field, are discussed in terms of topological stagnation graphs and three-dimensional streamline plots. The models are validated by documenting their ability to explain magnetic susceptibility and nuclear magnetic shieldings of carbon and hydrogen via related shielding density maps

  7. Current amplification models of sensorineurall and conductive hearing loss

    OpenAIRE

    Ostojić, Sanja; Mikić, Branka; Mirić, Danica

    2012-01-01

    The main function of a hearing aid is to improve auditory and language abilities of hearing impaired users. The amplification model has to be adapted according to age, degree and type of hearing loss. The goal of this paper is to analyze the current amplification models of sensorineural and conductive hearing loss which can provide a high quality of speech perception and sounds at any degree of hearing loss. The BAHA is a surgically implantable system for treatment of conductive hearing loss ...

  8. Bayesian inference of chemical kinetic models from proposed reactions

    KAUST Repository

    Galagali, Nikhil; Marzouk, Youssef M.

    2015-01-01

    © 2014 Elsevier Ltd. Bayesian inference provides a natural framework for combining experimental data with prior knowledge to develop chemical kinetic models and quantify the associated uncertainties, not only in parameter values but also in model

  9. Current State of the Art Historic Building Information Modelling

    Science.gov (United States)

    Dore, C.; Murphy, M.

    2017-08-01

    In an extensive review of existing literature a number of observations were made in relation to the current approaches for recording and modelling existing buildings and environments: Data collection and pre-processing techniques are becoming increasingly automated to allow for near real-time data capture and fast processing of this data for later modelling applications. Current BIM software is almost completely focused on new buildings and has very limited tools and pre-defined libraries for modelling existing and historic buildings. The development of reusable parametric library objects for existing and historic buildings supports modelling with high levels of detail while decreasing the modelling time. Mapping these parametric objects to survey data, however, is still a time-consuming task that requires further research. Promising developments have been made towards automatic object recognition and feature extraction from point clouds for as-built BIM. However, results are currently limited to simple and planar features. Further work is required for automatic accurate and reliable reconstruction of complex geometries from point cloud data. Procedural modelling can provide an automated solution for generating 3D geometries but lacks the detail and accuracy required for most as-built applications in AEC and heritage fields.

  10. IMPROVING THE INTEROPERABILITY OF DISASTER MODELS: A CASE STUDY OF PROPOSING FIREML FOR FOREST FIRE MODEL

    Directory of Open Access Journals (Sweden)

    W. Jiang

    2018-04-01

    Full Text Available This paper presents a new standardized data format named Fire Markup Language (FireML, extended by the Geography Markup Language (GML of OGC, to elaborate upon the fire hazard model. The proposed FireML is able to standardize the input and output documents of a fire model for effectively communicating with different disaster management systems to ensure a good interoperability. To demonstrate the usage of FireML and testify its feasibility, an adopted forest fire spread model being compatible with FireML is described. And a 3DGIS disaster management system is developed to simulate the dynamic procedure of forest fire spread with the defined FireML documents. The proposed approach will enlighten ones who work on other disaster models' standardization work.

  11. Improving the Interoperability of Disaster Models: a Case Study of Proposing Fireml for Forest Fire Model

    Science.gov (United States)

    Jiang, W.; Wang, F.; Meng, Q.; Li, Z.; Liu, B.; Zheng, X.

    2018-04-01

    This paper presents a new standardized data format named Fire Markup Language (FireML), extended by the Geography Markup Language (GML) of OGC, to elaborate upon the fire hazard model. The proposed FireML is able to standardize the input and output documents of a fire model for effectively communicating with different disaster management systems to ensure a good interoperability. To demonstrate the usage of FireML and testify its feasibility, an adopted forest fire spread model being compatible with FireML is described. And a 3DGIS disaster management system is developed to simulate the dynamic procedure of forest fire spread with the defined FireML documents. The proposed approach will enlighten ones who work on other disaster models' standardization work.

  12. Proposal of a Modelling of the Innovation Process in an International Manufacturing Company

    Directory of Open Access Journals (Sweden)

    Pauline Lacom

    2017-07-01

    Full Text Available Nowadays, to cope with the competition, and to ensure the durability of their activities, companies have to be able to innovate. Manufacturing companies operating in a B2B market often perceive innovation as a technological result. However, innovation is often more characterized as a process. The needs of the users, and not only the technology, can achieve innovation. In this context, our paper intends to determine how to involve better the users in the innovation process of an international manufacturing company, which is, according to us, representative of the current manufacturing companies. The aim of our research paper is to help manufacturing companies to manage innovation led by users, and to implement their innovation process so that they will be able to set up specific tools for each action of the process. The study proposes a diagram-based language Structured Analysis and Design Technique (SADT that is based on the normative guide FD X50-271 of the French national organization for standardization (AFNOR. The SADT model we propose usefully complements this guide, to make the innovation process more understandable, practical and operational, for manufacturing companies, which are often helpless when faced with the subject. A critical analysis of the model we propose completed in a manufacturing company through semi-structured interviews of the innovation team and questionnaire for all the employees shows the application of the model in the company.

  13. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    ROSENTHAL, STEPHEN E.; DESJARLAIS, MICHAEL P.; SPIELMAN, RICK B.; STYGAR, WILLIAM A.; ASAY, JAMES R.; DOUGLAS, M.R.; HALL, C.A.; FRESE, M.H.; MORSE, R.L.; REISMAN, D.B.

    2000-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator, the authors have revisited a problem first described in detail by Heinz Knoepfel. Unlike the 1-Tesla MITLs of pulsed power accelerators used to produce intense particle beams, Z's disc transmission line (downstream of the current addition) is in a 100--1,200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 they have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are (1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into the MHD computations. Certain features are strongly dependent on the details of the conductivity model

  14. The nonparametric bootstrap for the current status model

    NARCIS (Netherlands)

    Groeneboom, P.; Hendrickx, K.

    2017-01-01

    It has been proved that direct bootstrapping of the nonparametric maximum likelihood estimator (MLE) of the distribution function in the current status model leads to inconsistent confidence intervals. We show that bootstrapping of functionals of the MLE can however be used to produce valid

  15. Modeling current climate conditions for forest pest risk assessment

    Science.gov (United States)

    Frank H. Koch; John W. Coulston

    2010-01-01

    Current information on broad-scale climatic conditions is essential for assessing potential distribution of forest pests. At present, sophisticated spatial interpolation approaches such as the Parameter-elevation Regressions on Independent Slopes Model (PRISM) are used to create high-resolution climatic data sets. Unfortunately, these data sets are based on 30-year...

  16. MHD Modeling of Conductors at Ultra-High Current Density

    International Nuclear Information System (INIS)

    Rosenthal, S.E.; Asay, J.R.; Desjarlais, M.P.; Douglas, M.R.; Frese, M.H.; Hall, C.A.; Morse, R.L.; Reisman, D.; Spielman, R.B.; Stygar, W.A.

    1999-01-01

    In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed

  17. [Neither Descartes nor Freud? current pain models in psychosomatic medicine].

    Science.gov (United States)

    Egloff, N; Egle, U T; von Känel, R

    2008-05-14

    Models explaining chronic pain based on the mere presence or absence of peripheral somatic findings or which view pain of psychological origin when there is no somatic explanation, have their shortcomings. Current scientific knowledge calls for distinct pain concepts, which integrate neurobiological and neuropsychological aspects of pain processing.

  18. Cognitive-behavior therapy for problem gambling: a critique of current treatments and proposed new unified approach.

    Science.gov (United States)

    Tolchard, Barry

    2017-06-01

    There is evidence supporting the use of cognitive-behavioral therapy (CBT) in the treatment of problem gambling. Despite this, little is known about how CBT works and which particular approach is most effective. This paper aims to synthesize the evidence for current CBT and propose a more unified approach to treatment. A literature review and narrative synthesis of the current research evidence of CBT for the treatment of problem gambling was conducted, focusing on the underlying mechanisms within the treatment approach. Several CBT approaches were critiqued. These can be divided into forms of exposure therapy (including aversion techniques, systematic desensitization and other behavioral experiments) those focusing on cognitive restructuring techniques (such as reinforcement of nongambling activity, use of diaries, motivational enhancement and audio-playback techniques and third wave techniques including mindfulness. Findings, in relation to the treatment actions, from this synthesis are reported. The debate surrounding the treatment of problem gambling has been conducted as an either/or rather than a both/and discourse. This paper proposes a new, unified approach to the treatment of problem gambling that incorporates the best elements of both exposure and cognitive restructuring techniques, alongside the use of techniques borrowed from mindfulness and other CBT approaches.

  19. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  20. Transport critical current density in flux creep model

    International Nuclear Information System (INIS)

    Wang, J.; Taylor, K.N.R.; Russell, G.J.; Yue, Y.

    1992-01-01

    The magnetic flux creep model has been used to derive the temperature dependence of the critical current density in high temperature superconductors. The generally positive curvature of the J c -T diagram is predicted in terms of two interdependent dimensionless fitting parameters. In this paper, the results are compared with both SIS and SNS junction models of these granular materials, neither of which provides a satisfactory prediction of the experimental data. A hybrid model combining the flux creep and SNS mechanisms is shown to be able to account for the linear regions of the J c -T behavior which are observed in some materials

  1. Spherical aberration correction with an in-lens N-fold symmetric line currents model.

    Science.gov (United States)

    Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji

    2018-04-01

    In our previous works, we have proposed N-SYLC (N-fold symmetric line currents) models for aberration correction. In this paper, we propose "in-lens N-SYLC" model, where N-SYLC overlaps rotationally symmetric lens. Such overlap is possible because N-SYLC is free of magnetic materials. We analytically prove that, if certain parameters of the model are optimized, an in-lens 3-SYLC (N = 3) doublet can correct 3rd order spherical aberration. By computer simulation, we show that the required excitation current for correction is less than 0.25 AT for beam energy 5 keV, and the beam size after correction is smaller than 1 nm at the corrector image plane for initial slope less than 4 mrad. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Proposing a Capability Perspective on Digital Business Models

    OpenAIRE

    Bärenfänger, Rieke; Otto, Boris

    2015-01-01

    Business models comprehensively describe the functioning of businesses in contemporary economic, technological, and societal environments. This paper focuses on the characteristics of digital business models from the perspective of capability research and develops a capability model for digital businesses. Following the design science research (DSR) methodology, multiple evaluation and design iterations were performed. Contributions to the design process came from IS/IT practice and the resea...

  3. A two dimensional model of undertow current over mud bed

    International Nuclear Information System (INIS)

    Mir Hammadul Azam; Abdul Aziz Ibrahim; Noraieni Hj, Mokhtar

    1996-01-01

    Coastal wave-current dynamics often causes severe erosion and this activity is more prominent within the surf zone. Turbulence generated by breaking wave is a complex phenomena and the degree of complexity increases to a higher degree when it happens over mud bed. A better understanding on wave and current is necessary to enrich the engineering hand to facilitate any coastal development work. Since physical model has certain deficiencies, such as high cost and scaling problem, the need for developing numerical models in such cases is significant. A time averaged two dimensional model has been developed to simulate the undertow over mud bed. A turbulent energy model also included which considers only the vertical variation of mixing length. Production of turbulent kinetic energy in the surf zone has been calculated from an hydraulic jump analogy. The result obtained shows an insignificant vertical variation of current. Further research is needed involving laboratory and field works to get sufficient data for comparing the model results

  4. A proposed model for paradigmatic relations within an emergent discipline

    Directory of Open Access Journals (Sweden)

    Jack D. Glazier

    2002-01-01

    Full Text Available This article is the vehicle for purposing a model for mapping the processual change associated with disciplinary and paradigmatic development. Change of this sort is contingent on the degree of consistency achieved within theory groups. Consistency, in this case, is equated theory and paradigm dominance. The symbolic interactionist tradition supplies the assumptions on which the model is grounded. Examination of the model is accomplished by contrasting it with Thomas Kuhn’s theory. The recent history of library and information science education in the U.S. serves as context and exemplar for application of the model

  5. Proposing an Environmental Excellence Self-Assessment Model

    DEFF Research Database (Denmark)

    Meulengracht Jensen, Peter; Johansen, John; Wæhrens, Brian Vejrum

    2013-01-01

    that the EEA model can be used in global organizations to differentiate environmental efforts depending on the maturity stage of the individual sites. Furthermore, the model can be used to support the decision-making process regarding when organizations should embark on more complex environmental efforts......This paper presents an Environmental Excellence Self-Assessment (EEA) model based on the structure of the European Foundation of Quality Management Business Excellence Framework. Four theoretical scenarios for deploying the model are presented as well as managerial implications, suggesting...

  6. How well do basic models describe the turbidity currents coming down Monterey and Congo Canyon?

    Science.gov (United States)

    Cartigny, M.; Simmons, S.; Heerema, C.; Xu, J. P.; Azpiroz, M.; Clare, M. A.; Cooper, C.; Gales, J. A.; Maier, K. L.; Parsons, D. R.; Paull, C. K.; Sumner, E. J.; Talling, P.

    2017-12-01

    Turbidity currents rival rivers in their global capacity to transport sediment and organic carbon. Furthermore, turbidity currents break submarine cables that now transport >95% of our global data traffic. Accurate turbidity current models are thus needed to quantify their transport capacity and to predict the forces exerted on seafloor structures. Despite this need, existing numerical models are typically only calibrated with scaled-down laboratory measurements due to the paucity of direct measurements of field-scale turbidity currents. This lack of calibration thus leaves much uncertainty in the validity of existing models. Here we use the most detailed observations of turbidity currents yet acquired to validate one of the most fundamental models proposed for turbidity currents, the modified Chézy model. Direct measurements on which the validation is based come from two sites that feature distinctly different flow modes and grain sizes. The first are from the multi-institution Coordinated Canyon Experiment (CCE) in Monterey Canyon, California. An array of six moorings along the canyon axis captured at least 15 flow events that lasted up to hours. The second is the deep-sea Congo Canyon, where 10 finer grained flows were measured by a single mooring, each lasting several days. Moorings captured depth-resolved velocity and suspended sediment concentration at high resolution (turbidity currents; the modified Chézy model. This basic model has been very useful for river studies over the past 200 years, as it provides a rapid estimate of how flow velocity varies with changes in river level and energy slope. Chézy-type models assume that the gravitational force of the flow equals the friction of the river-bed. Modified Chézy models have been proposed for turbidity currents. However, the absence of detailed measurements of friction and sediment concentration within full-scale turbidity currents has forced modellers to make rough assumptions for these parameters. Here

  7. The opinion of Turkish cardiologists on current malpractice system and an alternative patient compensation system proposal: PCS study group.

    Science.gov (United States)

    Olcay, Ayhan; Emren, Sadık Volkan; Babür Güler, Gamze; Güler, Ekrem; Ertunç, Vedat; Berilgen, Rida; Aslan, Abdullah; Şimşek, Ersin Çağrı; Gölcük, Şükriye Ebru; Yalın, Kıvanç

    2017-10-01

    Cardiologists participate in the diagnosis and interventional treatment of numerous high-risk patients. The goal of this study was to investigate how the current malpractice system in Turkey influences cardiologists' diagnostic and interventional behavior and to obtain their opinions about an alternative patient compensation system. The present cross-sectional study assessed the practice of defensive medicine among cardiologists who are actively working in various types of workplace within the Turkish healthcare system. A 24-item questionnaire was distributed to cardiology residents, specialists, and academics in Turkey in print format, by electronic mail, or via cell phone message. A total of 253 cardiologists responded to the survey. Among them, 29 (11.6%) had been sued for malpractice claims in the past. Of the cardiologists who had been sued, 2 (6.9%) had been ordered to pay financial compensation, and 1 (3.4%) was given a sentence of imprisonment due to negligence. In all, 132 (52.8%) of the surveyed cardiologists reported that they had changed their practices due to fear of litigation, and 232 (92.8%) reported that they would prefer the new proposed patient compensation system to the current malpractice system. Among the cardiologists surveyed, 78.8% indicated that malpractice fear had affected their decision-making with regard to requesting computed tomography angiography or thallium scintigraphy, 71.6% for coronary angiography, 20% for stent implantation, and 83.2% for avoiding treating high-risk patients. The results of this survey demonstrated that cardiologists may request unnecessary tests and perform unneeded interventions due to the fear of malpractice litigation fear. Many also avoid high-risk patients and interventions. The majority indicated that they would prefer the proposed alternative patient compensation system to the current malpractice system.

  8. Citygml and the Streets of New York - a Proposal for Detailed Street Space Modelling

    Science.gov (United States)

    Beil, C.; Kolbe, T. H.

    2017-10-01

    Three-dimensional semantic city models are increasingly used for the analysis of large urban areas. Until now the focus has mostly been on buildings. Nonetheless many applications could also benefit from detailed models of public street space for further analysis. However, there are only few guidelines for representing roads within city models. Therefore, related standards dealing with street modelling are examined and discussed. Nearly all street representations are based on linear abstractions. However, there are many use cases that require or would benefit from the detailed geometrical and semantic representation of street space. A variety of potential applications for detailed street space models are presented. Subsequently, based on related standards as well as on user requirements, a concept for a CityGML-compliant representation of street space in multiple levels of detail is developed. In the course of this process, the CityGML Transportation model of the currently valid OGC standard CityGML2.0 is examined to discover possibilities for further developments. Moreover, a number of improvements are presented. Finally, based on open data sources, the proposed concept is implemented within a semantic 3D city model of New York City generating a detailed 3D street space model for the entire city. As a result, 11 thematic classes, such as roadbeds, sidewalks or traffic islands are generated and enriched with a large number of thematic attributes.

  9. Futility Disputes: A Review of the Literature and Proposed Model for Dispute Navigation Through Trust Building.

    Science.gov (United States)

    Leland, Brian D; Torke, Alexia M; Wocial, Lucia D; Helft, Paul R

    2017-10-01

    Futility disputes in the intensive care unit setting have received significant attention in the literature over the past several years. Although the idea of improving communication in an attempt to resolve these challenging situations has been regularly discussed, the concept and role of trust building as the means by which communication improves and disputes are best navigated is largely absent. We take this opportunity to review the current literature on futility disputes and argue the important role of broken trust in these encounters, highlighting current evidence establishing the necessity and utility of trust in both medical decision-making and effective communication. Finally, we propose a futility dispute navigation model built upon improved communication through trust building.

  10. Emendation of the family Chlamydiaceae: proposal of a single genus, Chlamydia, to include all currently recognized species.

    Science.gov (United States)

    Sachse, Konrad; Bavoil, Patrik M; Kaltenboeck, Bernhard; Stephens, Richard S; Kuo, Cho-Chou; Rosselló-Móra, Ramon; Horn, Matthias

    2015-03-01

    The family Chlamydiaceae (order Chlamydiales, phylum Chlamydiae) comprises important, obligate intracellular bacterial pathogens of humans and animals. Subdivision of the family into the two genera Chlamydia and Chlamydophila has been discussed controversially during the past decade. Here, we have revisited the current classification in the light of recent genomic data and in the context of the unique biological properties of these microorganisms. We conclude that neither generally used 16S rRNA sequence identity cut-off values nor parameters based on genomic similarity consistently separate the two genera. Notably, no easily recognizable phenotype such as host preference or tissue tropism is available that would support a subdivision. In addition, the genus Chlamydophila is currently not well accepted and not used by a majority of research groups in the field. Therefore, we propose the classification of all 11 currently recognized Chlamydiaceae species in a single genus, the genus Chlamydia. Finally, we provide emended descriptions of the family Chlamydiaceae, the genus Chlamydia, as well as the species Chlamydia abortus, Chlamydia caviae and Chlamydia felis. Copyright © 2015 Elsevier GmbH. All rights reserved.

  11. Current Challenges in the First Principle Quantitative Modelling of the Lower Hybrid Current Drive in Tokamaks

    Science.gov (United States)

    Peysson, Y.; Bonoli, P. T.; Chen, J.; Garofalo, A.; Hillairet, J.; Li, M.; Qian, J.; Shiraiwa, S.; Decker, J.; Ding, B. J.; Ekedahl, A.; Goniche, M.; Zhai, X.

    2017-10-01

    The Lower Hybrid (LH) wave is widely used in existing tokamaks for tailoring current density profile or extending pulse duration to steady-state regimes. Its high efficiency makes it particularly attractive for a fusion reactor, leading to consider it for this purpose in ITER tokamak. Nevertheless, if basics of the LH wave in tokamak plasma are well known, quantitative modeling of experimental observations based on first principles remains a highly challenging exercise, despite considerable numerical efforts achieved so far. In this context, a rigorous methodology must be carried out in the simulations to identify the minimum number of physical mechanisms that must be considered to reproduce experimental shot to shot observations and also scalings (density, power spectrum). Based on recent simulations carried out for EAST, Alcator C-Mod and Tore Supra tokamaks, the state of the art in LH modeling is reviewed. The capability of fast electron bremsstrahlung, internal inductance li and LH driven current at zero loop voltage to constrain all together LH simulations is discussed, as well as the needs of further improvements (diagnostics, codes, LH model), for robust interpretative and predictive simulations.

  12. Application of Eddy Currents in Medicine and their Modelling

    International Nuclear Information System (INIS)

    Krawczyk, A.; Wiak, S.; Zyss, T.; Sikora, R.

    1998-01-01

    The paper deals with the problems of interactions between the electromagnetic field and biological material, in particular the problem of eddy currents in human tissues and cells induced there for medical purposes, and the mathematical modeling of the phenomenon. The diagnostic and therapeutic effects of eddy currents are discussed and the advantages and drawbacks of these effects are given. A deeper analysis is devoted to the problem of transcranial magnetic stimulation (TMS) which is used in psychiatry as the treatment in depressive psychosis. (author)

  13. Dynamics of edge currents in a linearly quenched Haldane model

    Science.gov (United States)

    Mardanya, Sougata; Bhattacharya, Utso; Agarwal, Amit; Dutta, Amit

    2018-03-01

    In a finite-time quantum quench of the Haldane model, the Chern number determining the topology of the bulk remains invariant, as long as the dynamics is unitary. Nonetheless, the corresponding boundary attribute, the edge current, displays interesting dynamics. For the case of sudden and adiabatic quenches the postquench edge current is solely determined by the initial and the final Hamiltonians, respectively. However for a finite-time (τ ) linear quench in a Haldane nanoribbon, we show that the evolution of the edge current from the sudden to the adiabatic limit is not monotonic in τ and has a turning point at a characteristic time scale τ =τ0 . For small τ , the excited states lead to a huge unidirectional surge in the edge current of both edges. On the other hand, in the limit of large τ , the edge current saturates to its expected equilibrium ground-state value. This competition between the two limits lead to the observed nonmonotonic behavior. Interestingly, τ0 seems to depend only on the Semenoff mass and the Haldane flux. A similar dynamics for the edge current is also expected in other systems with topological phases.

  14. Modeling of Dual Gate Material Hetero-dielectric Strained PNPN TFET for Improved ON Current

    Science.gov (United States)

    Kumari, Tripty; Saha, Priyanka; Dash, Dinesh Kumar; Sarkar, Subir Kumar

    2018-01-01

    The tunnel field effect transistor (TFET) is considered to be a promising alternative device for future low-power VLSI circuits due to its steep subthreshold slope, low leakage current and its efficient performance at low supply voltage. However, the main challenging issue associated with realizing TFET for wide scale applications is its low ON current. To overcome this, a dual gate material with the concept of dielectric engineering has been incorporated into conventional TFET structure to tune the tunneling width at source-channel interface allowing significant flow of carriers. In addition to this, N+ pocket is implanted at source-channel junction of the proposed structure and the effect of strain is added for exploring the performance of the model in nanoscale regime. All these added features upgrade the device characteristics leading to higher ON current, low leakage and low threshold voltage. The present work derives the surface potential, electric field expression and drain current by solving 2D Poisson's equation at different boundary conditions. A comparative analysis of proposed model with conventional TFET has been done to establish the superiority of the proposed structure. All analytical results have been compared with the results obtained in SILVACO ATLAS device simulator to establish the accuracy of the derived analytical model.

  15. A Proposed Conceptual Model to Measure Unwarranted Practice Variation

    National Research Council Canada - National Science Library

    Barr, Andrew M

    2007-01-01

    .... Employing a unit of analysis of the U.S. Army healthcare system and utilizing research by Wennberg and the Institute of Medicine, a model describing healthcare quality in terms of unwarranted practice variation and healthcare outcomes...

  16. comparative analysis of some existing kinetic models with proposed

    African Journals Online (AJOL)

    IGNATIUS NWIDI

    two statistical parameters namely; linear regression coefficient of correlation (R2) and ... Keynotes: Heavy metals, Biosorption, Kinetics Models, Comparative analysis, Average Relative Error. 1. ... If the flow rate is low, a simple manual batch.

  17. Proposal for a new CAPE-OPEN Object Model

    Science.gov (United States)

    Process simulation applications require the exchange of significant amounts of data between the flowsheet environment, unit operation model, and thermodynamic server. Packing and unpacking various data types and exchanging data using structured text-based architectures, including...

  18. 2012 Community Earth System Model (CESM) Tutorial - Proposal to DOE

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Marika [National Center for Atmospheric Research, Boulder, CO (United States); Bailey, David A [National Center for Atmospheric Research, Boulder, CO (United States)

    2013-03-18

    The Community Earth System Model (CESM) is a fully-coupled, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate states. This document provides the agenda and list of participants for the conference. Web materials for all lectures and practical sessions available from: http://www.cesm.ucar.edu/events/tutorials/073012/ .

  19. A Drain Current Model Based on the Temperature Effect of a-Si:H Thin-Film Transistors

    International Nuclear Information System (INIS)

    Qiang Lei; Yao Ruo-He

    2012-01-01

    Based on the differential Ohm's law and Poisson's equation, an analytical model of the drain current for a-Si:H thin-film transistors is developed. This model is proposed to elaborate the temperature effect on the drain current, which indicates that the drain current is linear with temperature in the range of 290-360 K, and the results fit well with the experimental data

  20. Modeling of Pulsed Direct-Current Glow Discharge

    International Nuclear Information System (INIS)

    Du Mu; Zheng Yaru; Fan Yujia; Zhang Nan; Liu Chengsen; Wang Dezhen

    2010-01-01

    A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic calculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results.

  1. Static current-sheet models of quiescent prominences

    Science.gov (United States)

    Wu, F.; Low, B. C.

    1986-12-01

    A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

  2. A detailed neutronics comparison of the university of Florida training reactor (UFTR) current HEU and proposed LEU cores

    International Nuclear Information System (INIS)

    Dionne, B.; Haghighat, A.; Yi, C.; Smith, R.; Ghita, G.; Manalo, K.; Sjoden, G.; Huh, J.; Baciak, J.; Mock, T.; Wenner, M.; Matos, J.; Stillman, J.

    2006-01-01

    For over 35 years, the UFTR highly-enriched core has been safely operated. As part of the Reduced Enrichment for Research and Test Reactors Program, the core is currently being converted to low-enriched uranium fuel. The analyses presented in this paper were performed to verify that, from a neutronic perspective, a proposed low-enriched core can be operated as safely and as effectively as the highly-enriched core. Detailed Monte Carlo criticality calculations are performed to determine: i) Excess reactivity for different core configurations, ii) Individual integral blade worth and shutdown margin, iii) Reactivity coefficients and kinetic parameters, and iv) Flux profiles and core six-factor formula parameters. (authors)

  3. Product/Service-Systems: Proposal for models and terminology

    DEFF Research Database (Denmark)

    Matzen, Detlef; Tan, Adrian; Andreasen, Mogens Myrup

    2005-01-01

    very blurred and ill defined. This paper will try to identify the fundamental characteristics of PSS and propose a system of concepts that can be used to describe and discuss the phenomenon, for the purpose of developing new PSS solutions. Coming from a tradition of product development research......Over recent years a growing number of studies and research programmes have been conducted on the issue of product/service-systems (PSS) [1, 2] and results have been presented at this row of symposia [3, 4]. These studies usually analyse the potential of integrated solutions to reduce...... the environmental impacts of human consumption activity or optimise a company’s ability to cope with the influences arising from the emerging globalisation of economic and business activities. Since there has not been worked on a coherent terminology for the terms and concepts used in PSS research, the area remains...

  4. Modeling microcirculatory blood flow: current state and future perspectives.

    Science.gov (United States)

    Gompper, Gerhard; Fedosov, Dmitry A

    2016-01-01

    Microvascular blood flow determines a number of important physiological processes of an organism in health and disease. Therefore, a detailed understanding of microvascular blood flow would significantly advance biophysical and biomedical research and its applications. Current developments in modeling of microcirculatory blood flow already allow to go beyond available experimental measurements and have a large potential to elucidate blood flow behavior in normal and diseased microvascular networks. There exist detailed models of blood flow on a single cell level as well as simplified models of the flow through microcirculatory networks, which are reviewed and discussed here. The combination of these models provides promising prospects for better understanding of blood flow behavior and transport properties locally as well as globally within large microvascular networks. © 2015 Wiley Periodicals, Inc.

  5. Reconstruction of electrocardiogram using ionic current models for heart muscles.

    Science.gov (United States)

    Yamanaka, A; Okazaki, K; Urushibara, S; Kawato, M; Suzuki, R

    1986-11-01

    A digital computer model is presented for the simulation of the electrocardiogram during ventricular activation and repolarization (QRS-T waves). The part of the ventricular septum and the left ventricular free wall of the heart are represented by a two dimensional array of 730 homogeneous functional units. Ionic currents models are used to determine the spatial distribution of the electrical activities of these units at each instant of time during simulated cardiac cycle. In order to reconstruct the electrocardiogram, the model is expanded three-dimensionally with equipotential assumption along the third axis and then the surface potentials are calculated using solid angle method. Our digital computer model can be used to improve the understanding of the relationship between body surface potentials and intracellular electrical events.

  6. Psychological debriefing (PD of trauma: a proposed model for Africa

    Directory of Open Access Journals (Sweden)

    E L Van Dyk

    2010-03-01

    Full Text Available Africa is a continent with severe trauma. Traumatic events include experiences of child soldiers, people living in war and conflict zones, and people struggling with the HIV/AIDS pandemic. These events cause high levels of trauma. The trauma causes psychological disorders like post traumatic stress disorder, acute stress disorder and combat stress reaction, specific in the military environment. This article focuses on a better understanding of the implications of trauma for military people and civilians. It discusses the different theories and models of psychological debriefing. Lastly the article discusses psychological debriefing models for military forces and the civil ian population to prevent severe psychopathology after traumatic incidents in Africa.

  7. The Role of Wakes in Modelling Tidal Current Turbines

    Science.gov (United States)

    Conley, Daniel; Roc, Thomas; Greaves, Deborah

    2010-05-01

    The eventual proper development of arrays of Tidal Current Turbines (TCT) will require a balance which maximizes power extraction while minimizing environmental impacts. Idealized analytical analogues and simple 2-D models are useful tools for investigating questions of a general nature but do not represent a practical tool for application to realistic cases. Some form of 3-D numerical simulations will be required for such applications and the current project is designed to develop a numerical decision-making tool for use in planning large scale TCT projects. The project is predicated on the use of an existing regional ocean modelling framework (the Regional Ocean Modelling System - ROMS) which is modified to enable the user to account for the effects of TCTs. In such a framework where mixing processes are highly parametrized, the fidelity of the quantitative results is critically dependent on the parameter values utilized. In light of the early stage of TCT development and the lack of field scale measurements, the calibration of such a model is problematic. In the absence of explicit calibration data sets, the device wake structure has been identified as an efficient feature for model calibration. This presentation will discuss efforts to design an appropriate calibration scheme which focuses on wake decay and the motivation for this approach, techniques applied, validation results from simple test cases and limitations shall be presented.

  8. Quark model calculations of current correlators in the nonperturbative domain

    International Nuclear Information System (INIS)

    Celenza, L.S.; Shakin, C.M.; Sun, W.D.

    1995-01-01

    The authors study the vector-isovector current correlator in this work, making use of a generalized Nambu-Jona-Lasinio (NJL) model. In their work, the original NJL model is extended to describe the coupling of the quark-antiquark states to the two-pion continuum. Further, a model for confinement is introduced that is seen to remove the nonphysical cuts that appear in various amplitudes when the quark and antiquark go on mass shell. Quite satisfactory results are obtained for the correlator. The authors also use the correlator to define a T-matrix for confined quarks and discuss a rho-dominance model for that T-matrix. It is also seen that the Bethe-Salpeter equation that determines the rho mass (in the absence of the coupling to the two-pion continuum) has more satisfactory behavior in the generalized model than in the model without confinement. That improved behavior is here related to the absence of the q bar q cut in the basic quark-loop integral of the generalized model. In this model, it is seen how one may work with both quark and hadron degrees of freedom, with only the hadrons appearing as physical particles. 12 refs., 16 figs., 1 tab

  9. Resistive switching near electrode interfaces: Estimations by a current model

    Science.gov (United States)

    Schroeder, Herbert; Zurhelle, Alexander; Stemmer, Stefanie; Marchewka, Astrid; Waser, Rainer

    2013-02-01

    The growing resistive switching database is accompanied by many detailed mechanisms which often are pure hypotheses. Some of these suggested models can be verified by checking their predictions with the benchmarks of future memory cells. The valence change memory model assumes that the different resistances in ON and OFF states are made by changing the defect density profiles in a sheet near one working electrode during switching. The resulting different READ current densities in ON and OFF states were calculated by using an appropriate simulation model with variation of several important defect and material parameters of the metal/insulator (oxide)/metal thin film stack such as defect density and its profile change in density and thickness, height of the interface barrier, dielectric permittivity, applied voltage. The results were compared to the benchmarks and some memory windows of the varied parameters can be defined: The required ON state READ current density of 105 A/cm2 can only be achieved for barriers smaller than 0.7 eV and defect densities larger than 3 × 1020 cm-3. The required current ratio between ON and OFF states of at least 10 requests defect density reduction of approximately an order of magnitude in a sheet of several nanometers near the working electrode.

  10. Assessment of current and proposed nature reserves of Mexico based on their capacity to protect geophysical features and biodiversity

    Science.gov (United States)

    Cantu, C.; Wright, R.G.; Scott, J.M.; Strand, Espen

    2004-01-01

    Mexico currently has 144 nature reserves covering approximately 9.1% of its land area. These reserves were established for a variety of reasons - often unrelated to the protection of biodiversity. In 2000 in response to a growing concern about the lack of organized conservation reserve planning to protect the important threatened biological and physical features of Mexico, the Mexican Commission for Knowledge and Use of Biodiversity (CONABIO) proposed the establishment of 151 new reserves for Mexico covering 51,429,500 ha. We compiled a GIS analysis using digital thematic maps of physical and biological features to examine how the existing and proposed reserves serve to protect the biodiversity and physical features of the country. Using a conservation target of placing a minimum of 12% of the land area of each important biophysical feature in nature reserves, we found that the 144 existing nature reserves covering 18 million ha (9% of the country) only meet that target for elevation ranges >3000 m and areas with poor soils. These mountainous areas represent less than 1% of the country. The gaps in the existing nature reserves network occur mainly at lower and intermediate elevations (<3000 m) areas with xeric, tropical, and temperate ecosystems, and high productivity soils. The areas proposed by CONABIO increase the proportion of protected lands in the country to over 27% and most of the conservation targets for geophysical features, and land cover, categories are met. Whether this area would be sufficient to maintain viable populations and ecological integrity of species and ecosystems is unknown. Even with the new reserves, low elevation coastal lands would be below the conservation target in the nature reserves. To include a representative sample of these lands would be difficult as these are the same areas where the majority of people live. ?? 2003 Elsevier Ltd. All rights reserved.

  11. Queering Constructs: Proposing a Dynamic Gender and Sexuality Model

    Science.gov (United States)

    Jourian, T. J.

    2015-01-01

    Higher education educators commonly understand social identities, including gender, to be fluid and dynamic. Lev's (2004) model of four components of sexual identity is commonly used to demonstrate the fluidity of sex, gender, and sexuality for individuals, but it does little to address the fixedness of those constructs. Through a multipronged…

  12. Proposing a Metaliteracy Model to Redefine Information Literacy

    Science.gov (United States)

    Jacobson, Trudi E.; Mackey, Thomas P.

    2013-01-01

    Metaliteracy is envisioned as a comprehensive model for information literacy to advance critical thinking and reflection in social media, open learning settings, and online communities. At this critical time in higher education, an expansion of the original definition of information literacy is required to include the interactive production and…

  13. [Individual rights vs public health in the fight against contagious diseases: proposals to improve the current legal framework].

    Science.gov (United States)

    Salamero Teixidó, Laura

    2016-11-01

    The public health protection constitutional mandate requires public powers to protect the population from contagious diseases. This requires a legal framework that both protects public health effectively and respects individual rights and freedoms that could be undermined by the public administrations. This article analyses, from a legal perspective, the current legal framework regulating the adoption of health measures to protect public health against contagious diseases. It argues that current regulations generate legal uncertainty on the basis of the wide range of discretionary powers they give to the public administration and the lack of provisions for limiting these powers. As a result, the guarantee mechanisms (primarily judicial consent) only weakly protect the rights and freedoms of the citizens affected by health measures. To conclude, the article proposes several amendments to improve public health regulations related to contagious diseases. The purpose is to render a legal framework that offers more legal certainty, in which it is possible to protect individual rights and freedoms when measures are adopted, without sacrificing the effective protection of public health. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. Current challenges facing the assessment of the allergenic capacity of food allergens in animal models

    DEFF Research Database (Denmark)

    Bøgh, Katrine Lindholm; van Bilsen, Jolanda; Głogowski, Robert

    2016-01-01

    of novel food proteins. There is no doubt that robust and reliable animal models for the identification and characterization of food allergens would be valuable tools for safety assessment. However, although various animal models have been proposed for this purpose, to date, none have been formally...... validated as predictive and none are currently suitable to test the allergenic potential of new foods. Here, the design of various animal models are reviewed, including among others considerations of species and strain, diet, route of administration, dose and formulation of the test protein, relevant...

  15. Proposing a Formalised Model for Mindful Information Systems Offshoring

    Science.gov (United States)

    Costello, Gabriel J.; Coughlan, Chris; Donnellan, Brian; Gadatsch, Andreas

    The central thesis of this chapter is that mathematical economics can provide a novel approach to the examination of offshoring business decisions and provide an impetus for future research in the area. A growing body of research indicates that projected cost savings from IT offshoring projects are not being met. Furthermore, evidence suggests that decision-making processes have been more emotional than rational, and that many offshoring arrangements have been rushed into without adequate analysis of the true costs involved. Building on the concept of mindfulness and mindlessness introduced to the IS literature by Swanson and Ramiller, a cost equation is developed using “deductive reasoning rather than inductive study” in the tradition of mathematical economics. The model endeavours to capture a wide range of both the quantitative and qualitative parameters. Although the economic model is illustrated against the background of a European scenario, the theoretical framework is generic and applicable to organisations in any global location.

  16. Proposal for a telehealth concept in the translational research model.

    Science.gov (United States)

    Silva, Angélica Baptista; Morel, Carlos Médicis; Moraes, Ilara Hämmerli Sozzi de

    2014-04-01

    To review the conceptual relationship between telehealth and translational research. Bibliographical search on telehealth was conducted in the Scopus, Cochrane BVS, LILACS and MEDLINE databases to find experiences of telehealth in conjunction with discussion of translational research in health. The search retrieved eight studies based on analysis of models of the five stages of translational research and the multiple strands of public health policy in the context of telehealth in Brazil. The models were applied to telehealth activities concerning the Network of Human Milk Banks, in the Telemedicine University Network. The translational research cycle of human milk collected, stored and distributed presents several integrated telehealth initiatives, such as video conferencing, and software and portals for synthesizing knowledge, composing elements of an information ecosystem, mediated by information and communication technologies in the health system. Telehealth should be composed of a set of activities in a computer mediated network promoting the translation of knowledge between research and health services.

  17. Proposal of a model of mammalian neural induction

    Science.gov (United States)

    Levine, Ariel J.; Brivanlou, Ali H.

    2009-01-01

    How does the vertebrate embryo make a nervous system? This complex question has been at the center of developmental biology for many years. The earliest step in this process – the induction of neural tissue – is intimately linked to patterning of the entire early embryo, and the molecular and embryological basis these processes are beginning to emerge. Here, we analyze classic and cutting-edge findings on neural induction in the mouse. We find that data from genetics, tissue explants, tissue grafting, and molecular marker expression support a coherent framework for mammalian neural induction. In this model, the gastrula organizer of the mouse embryo inhibits BMP signaling to allow neural tissue to form as a default fate – in the absence of instructive signals. The first neural tissue induced is anterior and subsequent neural tissue is posteriorized to form the midbrain, hindbrain, and spinal cord. The anterior visceral endoderm protects the pre-specified anterior neural fate from similar posteriorization, allowing formation of forebrain. This model is very similar to the default model of neural induction in the frog, thus bridging the evolutionary gap between amphibians and mammals. PMID:17585896

  18. A current induced diffusion model of gas sputtering

    International Nuclear Information System (INIS)

    Hotston, E.S.

    1980-01-01

    A model is proposed to explain the experimental results on deuteron trapping in stainless steel targets at low temperatures carried out at Garching and Culham. The model proposes that the ions are trapped in two kinds of sites: Deep sites with high activation energy and shallow sites of low activation energy. Trapped deuterons reach the surface of the target by being expelled from shallow sites by the action of the ion beam and migrate to nearby sites in a random way, thus moving by a bombardment induced diffusion. Ions diffusing to the target surface and being released are said to be sputtered from the target. It has been necessary to assume numerical values for sizes of some of the processes which occur. With a suitable choice of values the model successfully predicts the numbers of deuterons trapped per unit area of the target, the obserbed density profile of the trapped ions and the threshold at which sputtering starts. The model also successfully describes the replacement of the trapped deuterons by protons, when the deuteron beam is replaced by a proton beam. The collision cross-section for beam ions and ions trapped in shallow sites is too large, 4 x 10 -13 cm 2 , for a binary collision and it is tentatively suggested that the ions in the shallow sites may be in small voids in the target which may be connected with blister formation. Comparison of the present model with one being developed to describe the trapping of deuterons in carbon suggests that it may be possible to describe all gas sputtering experiments in terms of diffusion processes. (orig.)

  19. Nanoinformatics workshop report: Current resources, community needs, and the proposal of a collaborative framework for data sharing and information integration.

    Science.gov (United States)

    Harper, Stacey L; Hutchison, James E; Baker, Nathan; Ostraat, Michele; Tinkle, Sally; Steevens, Jeffrey; Hoover, Mark D; Adamick, Jessica; Rajan, Krishna; Gaheen, Sharon; Cohen, Yoram; Nel, Andre; Cachau, Raul E; Tuominen, Mark

    2013-01-01

    The quantity of information on nanomaterial properties and behavior continues to grow rapidly. Without a concerted effort to collect, organize and mine disparate information coming out of current research efforts, the value and effective use of this information will be limited at best. Data will not be translated to knowledge. At worst, erroneous conclusions will be drawn and future research may be misdirected. Nanoinformatics can be a powerful approach to enhance the value of global information in nanoscience and nanotechnology. Much progress has been made through grassroots efforts in nanoinformatics resulting in a multitude of resources and tools for nanoscience researchers. In 2012, the nanoinformatics community believed it was important to critically evaluate and refine currently available nanoinformatics approaches in order to best inform the science and support the future of predictive nanotechnology. The Greener Nano 2012: Nanoinformatics Tools and Resources Workshop brought together informatics groups with materials scientists active in nanoscience research to evaluate and reflect on the tools and resources that have recently emerged in support of predictive nanotechnology. The workshop goals were to establish a better understanding of current nanoinformatics approaches and to clearly define immediate and projected informatics infrastructure needs of the nanotechnology community. The theme of nanotechnology environmental health and safety (nanoEHS) was used to provide real-world, concrete examples on how informatics can be utilized to advance our knowledge and guide nanoscience. The benefit here is that the same properties that impact the performance of products could also be the properties that inform EHS. From a decision management standpoint, the dual use of such data should be considered a priority. Key outcomes include a proposed collaborative framework for data collection, data sharing and information integration.

  20. Nanoinformatics workshop report: current resources, community needs and the proposal of a collaborative framework for data sharing and information integration

    International Nuclear Information System (INIS)

    Harper, Stacey L; Hutchison, James E; Baker, Nathan; Ostraat, Michele; Tinkle, Sally; Steevens, Jeffrey; Hoover, Mark D; Adamick, Jessica; Rajan, Krishna; Gaheen, Sharon; Cohen, Yoram; Nel, Andre; Cachau, Raul E; Tuominen, Mark

    2013-01-01

    The quantity of information on nanomaterial properties and behavior continues to grow rapidly. Without a concerted effort to collect, organize and mine disparate information coming out of current research efforts, the value and effective use of this information will be limited at best. Data will not be translated to knowledge. At worst, erroneous conclusions will be drawn and future research may be misdirected. Nanoinformatics can be a powerful approach to enhance the value of global information in nanoscience and nanotechnology. Much progress has been made through grassroots efforts in nanoinformatics resulting in a multitude of resources and tools for nanoscience researchers. In 2012, the nanoinformatics community believed it was important to critically evaluate and refine currently available nanoinformatics approaches in order to best inform the science and support the future of predictive nanotechnology. The Greener Nano 2012: Nanoinformatics Tools and Resources Workshop brought together informatics groups with materials scientists active in nanoscience research to evaluate and reflect on the tools and resources that have recently emerged in support of predictive nanotechnology. The workshop goals were to establish a better understanding of current nanoinformatics approaches and to clearly define immediate and projected informatics infrastructure needs of the nanotechnology community. The theme of nanotechnology environmental health and safety (nanoEHS) was used to provide real-world, concrete examples on how informatics can be utilized to advance our knowledge and guide nanoscience. The benefit here is that the same properties that impact the performance of products could also be the properties that inform EHS. From a decision management standpoint, the dual use of such data should be considered a priority. Key outcomes include a proposed collaborative framework for data collection, data sharing and information integration. (paper)

  1. The spatial limitations of current neutral models of biodiversity.

    Directory of Open Access Journals (Sweden)

    Rampal S Etienne

    Full Text Available The unified neutral theory of biodiversity and biogeography is increasingly accepted as an informative null model of community composition and dynamics. It has successfully produced macro-ecological patterns such as species-area relationships and species abundance distributions. However, the models employed make many unrealistic auxiliary assumptions. For example, the popular spatially implicit version assumes a local plot exchanging migrants with a large panmictic regional source pool. This simple structure allows rigorous testing of its fit to data. In contrast, spatially explicit models assume that offspring disperse only limited distances from their parents, but one cannot as yet test the significance of their fit to data. Here we compare the spatially explicit and the spatially implicit model, fitting the most-used implicit model (with two levels, local and regional to data simulated by the most-used spatially explicit model (where offspring are distributed about their parent on a grid according to either a radially symmetric Gaussian or a 'fat-tailed' distribution. Based on these fits, we express spatially implicit parameters in terms of spatially explicit parameters. This suggests how we may obtain estimates of spatially explicit parameters from spatially implicit ones. The relationship between these parameters, however, makes no intuitive sense. Furthermore, the spatially implicit model usually fits observed species-abundance distributions better than those calculated from the spatially explicit model's simulated data. Current spatially explicit neutral models therefore have limited descriptive power. However, our results suggest that a fatter tail of the dispersal kernel seems to improve the fit, suggesting that dispersal kernels with even fatter tails should be studied in future. We conclude that more advanced spatially explicit models and tools to analyze them need to be developed.

  2. Modeling of leakage currents in high-k dielectrics

    International Nuclear Information System (INIS)

    Jegert, Gunther Christian

    2012-01-01

    Leakage currents are one of the major bottlenecks impeding the downscaling efforts of the semiconductor industry. Two core devices of integrated circuits, the transistor and, especially, the DRAM storage capacitor, suffer from the increasing loss currents. In this perspective a fundamental understanding of the physical origin of these leakage currents is highly desirable. However, the complexity of the involved transport phenomena so far has prevented the development of microscopic models. Instead, the analysis of transport through the ultra-thin layers of high-permittivity (high-k) dielectrics, which are employed as insulating layers, was carried out at an empirical level using simple compact models. Unfortunately, these offer only limited insight into the physics involved on the microscale. In this context the present work was initialized in order to establish a framework of microscopic physical models that allow a fundamental description of the transport processes relevant in high-k thin films. A simulation tool that makes use of kinetic Monte Carlo techniques was developed for this purpose embedding the above models in an environment that allows qualitative and quantitative analyses of the electronic transport in such films. Existing continuum approaches, which tend to conceal the important physics behind phenomenological fitting parameters, were replaced by three-dimensional transport simulations at the level of single charge carriers. Spatially localized phenomena, such as percolation of charge carriers across pointlike defects, being subject to structural relaxation processes, or electrode roughness effects, could be investigated in this simulation scheme. Stepwise a self-consistent, closed transport model for the TiN/ZrO 2 material system, which is of outmost importance for the semiconductor industry, was developed. Based on this model viable strategies for the optimization of TiN/ZrO 2 /TiN capacitor structures were suggested and problem areas that may

  3. Modeling of leakage currents in high-k dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Jegert, Gunther Christian

    2012-03-15

    Leakage currents are one of the major bottlenecks impeding the downscaling efforts of the semiconductor industry. Two core devices of integrated circuits, the transistor and, especially, the DRAM storage capacitor, suffer from the increasing loss currents. In this perspective a fundamental understanding of the physical origin of these leakage currents is highly desirable. However, the complexity of the involved transport phenomena so far has prevented the development of microscopic models. Instead, the analysis of transport through the ultra-thin layers of high-permittivity (high-k) dielectrics, which are employed as insulating layers, was carried out at an empirical level using simple compact models. Unfortunately, these offer only limited insight into the physics involved on the microscale. In this context the present work was initialized in order to establish a framework of microscopic physical models that allow a fundamental description of the transport processes relevant in high-k thin films. A simulation tool that makes use of kinetic Monte Carlo techniques was developed for this purpose embedding the above models in an environment that allows qualitative and quantitative analyses of the electronic transport in such films. Existing continuum approaches, which tend to conceal the important physics behind phenomenological fitting parameters, were replaced by three-dimensional transport simulations at the level of single charge carriers. Spatially localized phenomena, such as percolation of charge carriers across pointlike defects, being subject to structural relaxation processes, or electrode roughness effects, could be investigated in this simulation scheme. Stepwise a self-consistent, closed transport model for the TiN/ZrO{sub 2} material system, which is of outmost importance for the semiconductor industry, was developed. Based on this model viable strategies for the optimization of TiN/ZrO{sub 2}/TiN capacitor structures were suggested and problem areas

  4. Simulation of current generation in a 3-D plasma model

    International Nuclear Information System (INIS)

    Tsung, F.S.; Dawson, J.M.

    1996-01-01

    Two wires carrying current in the same direction will attract each other, and two wires carrying current in the opposite direction will repel each other. Now, consider a test charge in a plasma. If the test charge carries current parallel to the plasma, then it will be pulled toward the plasma core, and if the test charge carries current anti-parallel to the plasma, then it will be pushed to the edge. The electromagnetic coupling between the plasma and a test charge (i.e., the A parallel circ v parallel term in the test charge's Hamiltonian) breaks the symmetry in the parallel direction, and gives rise to a diffusion coefficient which is dependent on the particle's parallel velocity. This is the basis for the open-quotes preferential lossclose quotes mechanism described in the work by Nunan et al. In our previous 2+1/2 D work, in both cylindrical and toroidal geometries, showed that if the plasma column is centrally fueled, then an initial current increases steadily. The results in straight, cylindrical plasmas showed that self generated parallel current arises without trapped particle or neoclassical diffusion, as assumed by the bootstrap theory. It suggests that the fundamental mechanism seems to be the conservation of particles canonical momenta in the direction of the ignorable coordinate. We have extended the simulation to 3D to verify the model put forth. A scalable 3D EM-PIC code, with a localized field-solver, has been implemented to run on a large class of parallel computers. On the 512-node SP2 at Cornell Theory Center, we have benchmarked the 2+1/2 D calculations using 32 grids in the previously ignored direction, and a 100-fold increase in the number of particles. Our preliminary results show good agreements between the 2+1/2 D and the 3D calculations. We will present our 3D results at the meeting

  5. Modeling Earth Albedo Currents on Sun Sensors for Improved Vector Observations

    DEFF Research Database (Denmark)

    Bhanderi, Dan

    2006-01-01

    Earth albedo influences vector measurements of the solar line of sight vector, due to the induced current on in the photo voltaics of Sun sensors. Although advanced digital Sun sensors exist, these are typically expensive and may not be suited for satellites in the nano or pico-class. Previously...... an Earth albedo model, based on reflectivity data from NASA's Total Ozone Mapping Spectrometer project, has been published. In this paper the proposed model is presented, and the model is sought validated by comparing simulated data with telemetry from the Danish Ørsted satellite. A novel method...... for modeling Sun sensor output by incorporating the Earth albedo model is presented. This model utilizes the directional information of in the Earth albedo model, which is achieved by Earth surface partitioning. This allows accurate simulation of the Sun sensor output and the results are consistent with Ørsted...

  6. Additive Manufacturing and Business Models: Current Knowledge and Missing Perspectives

    Directory of Open Access Journals (Sweden)

    Christina Öberg

    2018-06-01

    Full Text Available Additive manufacturing, that is 3D printing technology, may change the way companies operate their businesses. This article adopts a business model perspective to create an understanding of what we know about these changes. It summarizes current knowledge on additive manufacturing within management and business research, and it discusses future research directions in relation to business models for additive manufacturing. Using the scientific database Web of Science, 116 journal articles were identified. The literature review reveals that most research concerns manufacturing optimization. A more holistic view of the changes that additive manufacturing may bring about for firms is needed, as is more research on changed value propositions, and customer/sales-related issues. The article contributes to previous research by systematically summarizing additive manufacturing research in the business and management literature, and by highlighting areas for further investigation related to the business models of individual firms.

  7. Evaluation of the Current State of Integrated Water Quality Modelling

    Science.gov (United States)

    Arhonditsis, G. B.; Wellen, C. C.; Ecological Modelling Laboratory

    2010-12-01

    Environmental policy and management implementation require robust methods for assessing the contribution of various point and non-point pollution sources to water quality problems as well as methods for estimating the expected and achieved compliance with the water quality goals. Water quality models have been widely used for creating the scientific basis for management decisions by providing a predictive link between restoration actions and ecosystem response. Modelling water quality and nutrient transport is challenging due a number of constraints associated with the input data and existing knowledge gaps related to the mathematical description of landscape and in-stream biogeochemical processes. While enormous effort has been invested to make watershed models process-based and spatially-distributed, there has not been a comprehensive meta-analysis of model credibility in watershed modelling literature. In this study, we evaluate the current state of integrated water quality modeling across the range of temporal and spatial scales typically utilized. We address several common modeling questions by providing a quantitative assessment of model performance and by assessing how model performance depends on model development. The data compiled represent a heterogeneous group of modeling studies, especially with respect to complexity, spatial and temporal scales and model development objectives. Beginning from 1992, the year when Beven and Binley published their seminal paper on uncertainty analysis in hydrological modelling, and ending in 2009, we selected over 150 papers fitting a number of criteria. These criteria involved publications that: (i) employed distributed or semi-distributed modelling approaches; (ii) provided predictions on flow and nutrient concentration state variables; and (iii) reported fit to measured data. Model performance was quantified with the Nash-Sutcliffe Efficiency, the relative error, and the coefficient of determination. Further, our

  8. A proposal of a renormalizable Nambu-Jona-Lasinio model

    Science.gov (United States)

    Cabo Montes de Oca, Alejandro

    2018-03-01

    A local and gauge invariant gauge field model including Nambu-Jona-Lasinio (NJL) and QCD Lagrangian terms in its action is introduced. Surprisingly, it becomes power counting renormalizable. This occurs thanks to the presence of action terms which modify the quark propagators, to become more decreasing that the Dirac one at large momenta in a Lee-Wick form, implying power counting renormalizability. The appearance of finite quark masses already in the tree approximation in the scheme is determined by the fact that the new action terms explicitly break chiral invariance. In this starting work we present the renormalized Feynman diagram expansion of the model and derive the formula for the degree of divergence of the diagrams. An explanation for the usual exclusion of the added Lagrangian terms is presented. In addition, the primitíve divergent graphs are identified. We start their evaluation by calculating the simpler contribution to the gluon polarization operator. The divergent and finite parts both result transverse as required by gauge invariance. The full evaluation of the various primitive divergences, which are required for completely defining the counterterm Feynman expansion will be considered in coming works, for further allowing to discuss the flavour symmetry breaking and unitarity.

  9. Lower hybrid current drive: an overview of simulation models, benchmarking with experiment, and predictions for future devices

    International Nuclear Information System (INIS)

    Bonoli, P.T.; Barbato, E.; Imbeaux, F.

    2003-01-01

    This paper reviews the status of lower hybrid current drive (LHCD) simulation and modeling. We first discuss modules used for wave propagation, absorption, and current drive with particular emphasis placed on comparing exact numerical solutions of the Fokker Planck equation in 2-dimension with solution methods that employ 1-dimensional and adjoint approaches. We also survey model predictions for LHCD in past and present experiments showing detailed comparisons between simulated and observed current drive efficiencies and hard X-ray profiles. Finally we discuss several model predictions for lower hybrid current profile control in proposed next step reactor options. (authors)

  10. Global Current Circuit Structure in a Resistive Pulsar Magnetosphere Model

    Science.gov (United States)

    Kato, Yugo. E.

    2017-12-01

    Pulsar magnetospheres have strong magnetic fields and large amounts of plasma. The structures of these magnetospheres are studied using force-free electrodynamics. To understand pulsar magnetospheres, discussions must include their outer region. However, force-free electrodynamics is limited in it does not handle dissipation. Therefore, a resistive pulsar magnetic field model is needed. To break the ideal magnetohydrodynamic (MHD) condition E\\cdot B=0, Ohm’s law is used. This work introduces resistivity depending upon the distance from the star and obtain a self-consistent steady state by time integration. Poloidal current circuits form in the magnetosphere while the toroidal magnetic field region expands beyond the light cylinder and the Poynting flux radiation appears. High electric resistivity causes a large space scale poloidal current circuit and the magnetosphere radiates a larger Poynting flux than the linear increase outside of the light cylinder radius. The formed poloidal-current circuit has width, which grows with the electric conductivity. This result contributes to a more concrete dissipative pulsar magnetosphere model.

  11. Model-independent determination of hadronic neutral-current couplings

    International Nuclear Information System (INIS)

    Claudson, M.; Paschos, E.A.; Strait, J.; Sulak, L.R.

    1979-01-01

    Completion of a second generation of experiments on neutrino-induced neutral-current reactions allows a more discriminating study of neutral-current couplings to hadrons. To minimize the sensitivity to model-dependent analyses of inclusive and exclusive pion data, we base our work on measurements of deep-inelastic and elastic reactions alone. Within the regions allowed by the deep-inelastic data for scattering on isoscalar targets, the coupling constants are fit to the q 2 dependence of the neutrino-proton elastic scattering data. This procedure initially yields two solutions for the couplings. One of these, at theta/sub L/ = 55 0 and theta/sub R/ = 205 0 , is predominantly isoscalar and therefore is ruled out by only qualitative consideration of exclusive pion data. The other solution at theta/sub D/ = 140 0 and and theta/sub R/ = 330 0 , is thus a unique determination of the hadronic neutral-current couplings. It coincides with solution A obtained in earlier work, and is insensitive to variations of M/sub A/ within 2 standard deviations of the world average. When constrained to the coupling constants required by the Weinberg-Salam model, the fit agrees with the data to within 1 standard deviation

  12. Modeling of finite aspect ratio effects on current drive

    International Nuclear Information System (INIS)

    Wright, J.C.; Phillips, C.K.

    1996-01-01

    Most 2D RF modeling codes use a parameterization of current drive efficiencies to calculate fast wave driven currents. This parameterization assumes a uniform diffusion coefficient and requires a priori knowledge of the wave polarizations. These difficulties may be avoided by a direct calculation of the quasilinear diffusion coefficient from the Kennel-Englemann form with the field polarizations calculated by a full wave code. This eliminates the need to use the approximation inherent in the parameterization. Current profiles are then calculated using the adjoint formulation. This approach has been implemented in the FISIC code. The accuracy of the parameterization of the current drive efficiency, η, is judged by a comparison with a direct calculation: where χ is the adjoint function, ε is the kinetic energy, and rvec Γ is the quasilinear flux. It is shown that for large aspect ratio devices (ε → 0), the parameterization is nearly identical to the direct calculation. As the aspect ratio approaches unity, visible differences between the two calculations appear

  13. Modeling geomagnetic induced currents in Australian power networks

    Science.gov (United States)

    Marshall, R. A.; Kelly, A.; Van Der Walt, T.; Honecker, A.; Ong, C.; Mikkelsen, D.; Spierings, A.; Ivanovich, G.; Yoshikawa, A.

    2017-07-01

    Geomagnetic induced currents (GICs) have been considered an issue for high-latitude power networks for some decades. More recently, GICs have been observed and studied in power networks located in lower latitude regions. This paper presents the results of a model aimed at predicting and understanding the impact of geomagnetic storms on power networks in Australia, with particular focus on the Queensland and Tasmanian networks. The model incorporates a "geoelectric field" determined using a plane wave magnetic field incident on a uniform conducting Earth, and the network model developed by Lehtinen and Pirjola (1985). Model results for two intense geomagnetic storms of solar cycle 24 are compared with transformer neutral monitors at three locations within the Queensland network and one location within the Tasmanian network. The model is then used to assess the impacts of the superintense geomagnetic storm of 29-31 October 2003 on the flow of GICs within these networks. The model results show good correlation with the observations with coefficients ranging from 0.73 to 0.96 across the observing sites. For Queensland, modeled GIC magnitudes during the superstorm of 29-31 October 2003 exceed 40 A with the larger GICs occurring in the south-east section of the network. Modeled GICs in Tasmania for the same storm do not exceed 30 A. The larger distance spans and general east-west alignment of the southern section of the Queensland network, in conjunction with some relatively low branch resistance values, result in larger modeled GICs despite Queensland being a lower latitude network than Tasmania.

  14. A Summary of Proposed Changes to the Current ICARTT Format Standards and their Implications to Future Airborne Studies

    Science.gov (United States)

    Northup, E. A.; Kusterer, J.; Quam, B.; Chen, G.; Early, A. B.; Beach, A. L., III

    2015-12-01

    The current ICARTT file format standards were developed for the purpose of fulfilling the data management needs for the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign in 2004. The goal of the ICARTT file format was to establish a common and simple to use data file format to promote data exchange and collaboration among science teams with similar science objectives. ICARTT has been the NASA standard since 2010, and is widely used by NOAA, NSF, and international partners (DLR, FAAM). Despite its level of acceptance, there are a number of issues with the current ICARTT format, especially concerning the machine readability. To enhance usability, the ICARTT Refresh Earth Science Data Systems Working Group (ESDSWG) was established to enable a platform for atmospheric science data producers, users (e.g. modelers) and data managers to collaborate on developing criteria for this file format. Ultimately, this is a cross agency effort to improve and aggregate the metadata records being produced. After conducting a survey to identify deficiencies in the current format, we determined which are considered most important to the various communities. Numerous recommendations were made to improve upon the file format while maintaining backward compatibility. The recommendations made to date and their advantages and limitations will be discussed.

  15. Modelling of the toroidal asymmetry of poloidal halo currents in conducting structures

    International Nuclear Information System (INIS)

    Pomphrey, N.; Bialek, J.M.; Part, W.

    1998-01-01

    During plasma disruptions, substantial toroidal and poloidal eddy currents are generated in the vacuum vessel and other plasma facing conducting structures. Eddy currents that conduct charge through paths which close through the plasma periphery are called halo currents, and these can be of substantial magnitude. Of particular concern for tokamak design and operation is the observed toroidal asymmetry of the halo current distribution: such an asymmetric distribution leads to problematic non-uniform forces on the conducting structures. The premise is adopted that the source of toroidal asymmetry is the plasma deformation resulting from the non-linear external kink instability that develops during the current quench phase of a disruption. A simple model is presented of the kinked plasma that allows an analytic calculation of the dependence of the toroidal peaking factor (TPF) on the ratio of the halo current to the total toroidal plasma current, I h /I p . Expressions for the TPF as a function of I h /I p are derived for m/n=2/1 and m/n=1/1 helical instabilities. The expressions depend on a single parameter, which measures the amplitude of the saturated state of the kink instability. A comparison with disruption data from experiments shows good agreement. Numerical experiments that simulate non-linear external kinks provide guidance on the values expected for the saturated amplitude. It is proposed that a simple plasma halo model is adequate for assessing the engineering impact of asymmetric halo currents, since the force distribution on the conducting structures depends mainly on the 'resistive distribution' of the eddy currents. A brief description is given of an electromagnetics code that calculates the time development of eddy currents in conducting structures, and the code is applied to two halo current disruption scenarios. These are used to emphasize the importance of having an accurate eddy current calculation to correctly estimate the engineering impact of

  16. Two-current nucleon observables in Skyrme model

    International Nuclear Information System (INIS)

    Chemtob, M.

    1987-01-01

    Three independent two-current nucleon observables are studied within the two-flavor Skyrme model for the πρω system. The effecive lagrangian is that of the gauged chiral symmetry approach, consistent with the vector meson dominance, in the linear realization (for the vector mesons) of the global chiral symmetry. The first application deals with the nucleon electric polarizability and magnetic susceptibility. Both seagull and dispersive contributions appear and we evaluate the latter in terms of the sums over intermediate states. The results are compared with existing quark model results as well as with empirical determinations. The second application concerns the zero-point quantum correction to the skyrmion mass. We apply a chiral perturbation theory approach to evaluate the ion loop contribution to the nucleon mass. The comparison with the conventional Skyrme model result reveals an important sensitivity to the stabilization mechanism. The third application is to lepton-nucleon deep inelastic scattering in the Bjorken scaling limit. The structure tensor is calculated in terms of the representation as a commutator product of two currents. Numerical results are presented for the scaling function F 2 (x). An essential use is made of the large N c (number of colors) approximation in all these applications. In the numerical computations we ignore the distortion effects, relative to the free plane wave limit, on the pionic fluctuations. (orig.)

  17. A proposed model of e-trust for electronic banking

    Directory of Open Access Journals (Sweden)

    Neda Yousefi

    2015-11-01

    Full Text Available Customer’s trust is the most important and one of the key factors of success in e-commerce. However, trust is the essential aspects of e-banking adoption and the main element for building long-term relationships with the bank's customers. So the purpose of this research is to investigate the factors influencing on customer′s trust in e-banking services and prioritize them. Therefore, designed questionnaire was distributed among 177 electronic service customers in number of banks in the city of Karaj, Iran. Likert quintuplet scales were used to measure the variables. After collecting the questionnaires, the data were analyzed by structural equation modeling (by using LISREL 8.5. The results revealed that quality of electronic services such as ease of use, privacy and security, individual characteristics of customers such as disposition to trust and features of bank such as reputation, size and dependence on government, have had the greatest effect on customer′s trust in e-banking services.

  18. Modeling of the sawtooth instability in tokamaks using a current viscosity term

    International Nuclear Information System (INIS)

    Ward, D.J.; Jardin, S.C.

    1988-08-01

    We propose a new method for modeling the sawtooth instability and other MHD activity in axisymmetric tokamak transport simulations. A hyper-resistivity (or current viscosity) term is included in the mean field Ohm's law to describe the effects of the three-dimensional fluctuating fields on the evolution of the inverse transform, q, characterizing the mean fields. This term has the effect of flattening the current profile, while dissipating energy and conserving helicity. A fully implicit MHD transport and 2-D toroidal equilibrium code has been developed to calculate the evolution in time of the q-profile and the current profile using this new term. The results of this code are compared to the Kadomtsev reconnection model in the circular cylindrical limit. 17 refs., 8 figs

  19. Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors

    International Nuclear Information System (INIS)

    Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A.

    2014-01-01

    A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped

  20. Modelling the effects of the sawtooth instability in tokamaks using a current viscosity term

    International Nuclear Information System (INIS)

    Ward, D.J.; Jardin, S.C.

    1989-01-01

    A new method for modelling the sawtooth instability and other MHD activity in axisymmetric tokamak transport simulations is proposed. A hyper-resistivity (or current viscosity) term is included in the mean field Ohm's law to describe the effects of the three-dimensional fluctuating fields on the evolution of the inverse transform q characterizing the mean fields. This term has the effect of flattening the current profile while dissipating energy and conserving helicity. A fully implicit MHD transport and two-dimensional toroidal equilibrium code has been developed to calculate the evolution in time of the q-profile and the current profile using this new term. The results of this code are compared with the Kadomtsev reconnection model in the circular cylindrical limit. (author). 26 refs, 10 figs

  1. Maternal hypothyroidism: An overview of current experimental models.

    Science.gov (United States)

    Ghanbari, Mahboubeh; Ghasemi, Asghar

    2017-10-15

    Maternal hypothyroidism (MH) is the most common cause of transient congenital hypothyroidism. Different animal models are used for assessing developmental effects of MH in offspring. The severity and status of hypothyroidism in animal models must be a reflection of the actual conditions in humans. To obtain comparable results with different clinical conditions, which lead to MH in humans, several factors have been suggested for researchers to consider before designing the experimental models. Regarding development of fetal body systems during pregnancy, interference at different times provides different results and the appropriate time for induction of hypothyroidism should be selected based on accurate time of development of the system under assessment. Other factors that should be taken into consideration include, physiological and biochemical differences between humans and other species, thyroid hormone-independent effects of anti-thyroid drugs, circadian rhythms in TSH secretion, sex differences, physical and psychological stress. This review addresses essential guidelines for selecting and managing the optimal animal model for MH as well as discussing the pros and cons of currently used models. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Current models of care for disorders of sex development

    DEFF Research Database (Denmark)

    Kyriakou, Andreas; Dessens, Arianne; Bryce, Jillian

    2016-01-01

    BACKGROUND: To explore the current models of practice in centres delivering specialist care for children with disorders of sex development (DSD), an international survey of 124 clinicians, identified through DSDnet and the I-DSD Registry, was performed in the last quarter of 2014. RESULTS: A total...... by 14 (19 %) centres. In addition to complex biochemistry and molecular genetic investigations, 40 clinicians (51 %) also had access to next generation sequencing. A genetic test was reported to be more preferable than biochemical tests for diagnosing 5-alpha reductase deficiency and 17-beta...

  3. Model-independent study of light cone current commutators

    International Nuclear Information System (INIS)

    Gautam, S.R.; Dicus, D.A.

    1974-01-01

    An attempt is made to extract information on the nature of light cone current commutators (L. C. C.) in a model independent manner. Using simple assumptions on the validity of the DGS representation for the structure functions of deep inelastic scattering and using the Bjorken--Johnston--Low theorem it is shown that in principle the L. C. C. may be constructed knowing the experimental electron--proton scattering data. On the other hand the scaling behavior of the structure functions is utilized to study the consistency of a vanishing value for various L. C. C. under mild assumptions on the behavior of the DGS spectral moments. (U.S.)

  4. SEAFLOOR MORPHOLOGY INFLUENCES ON CURRENT CONDITION IN A SUNDA STRAIT BRIDGE PROJECT USING NUMERICAL MODEL

    Directory of Open Access Journals (Sweden)

    Franto Novico

    2017-07-01

    Full Text Available It has been more than 50 years since the idea to construct the bridge of Sunda Strait was inspirited by Prof. Sedyatmo. This issued is very important due to accelerate the economic growth between Sumatera Island and Java Island which is known as the densest population in the Indonesia. However, until today the bridge is still not construct yet because the high budget and the lack of technical data are still being problems. One of the most important data is current condition along the Sunda Strait. Unfortunately, no one has been clearly studied about current condition along Sunda Strait. Therefore, the information about current condition would be completed to fulfil the lack of data and information. The RV Geomarine I, as a research vessel conducted the survey in October 2012 that one of the objectives is to get the impression about the current condition around the bridge plan. Attaching echo sounder of bathy 1500 to get the depth profile and applied the RD Instrument ADCP Mobile Workhorse Monitor 300 kHz to collect the real current data and analyze the current using numerical model by Mike 21 were carried out to describe the condition of the current around the bridge proposed. In addition, the detail flexible mesh of hydrodynamic model is applied along bridge plan to analyse the current condition that caused by seafloor morphology. Based on the ADCP data it would be seen that the highest velocity record of the current occurs at October 18th 2012 at line 19 with the value 2.63 m/sec. Nevertheless, the numerical model shown the highest current velocity occurs around the northwest of Sangiang Island where the speed attains more than 4.59 m/sec.

  5. Applications of CIVA NDE 10 on Eddy Current Modeling

    International Nuclear Information System (INIS)

    Nurul Ain Ahmad Latif; Ilham Mukhriz Zainal Abidin; AABdul Razak Hamzah

    2011-01-01

    CIVA NDE 10 is the simulation software and used as the platform to develop the models dedicated to Eddy Current testing (ET). It has various application in semi analytical modeling approaches. The focus of this paper is to simulate the signals response on the 40 % external groove of the Inconel 600 heat exchanger tubes with outside diameter of 22.22 mm. The inspection were simulated using 17 mm outside diameter differential probe with 100 kHz and 500 kHZ testing frequency. All the simulation results were validated using the experimental results integrated in the CIVA software. The configurations of the probe and tube consisting the flaw show the good agreement between the experimental and the simulated data. (author)

  6. Nuclear reactor fuel rod behavior modelling and current trends

    International Nuclear Information System (INIS)

    Colak, Ue.

    2001-01-01

    Safety assessment of nuclear reactors is carried out by simulating the events to taking place in nuclear reactors by realistic computer codes. Such codes are developed in a way that each event is represented by differential equations derived based on physical laws. Nuclear fuel is an important barrier against radioactive fission gas release. The release of radioactivity to environment is the main concern and this can be avoided by preserving the integrity of fuel rod. Therefore, safety analyses should cover an assessment of fuel rod behavior with certain extent. In this study, common approaches for fuel behavior modeling are discussed. Methods utilized by widely accepted computer codes are reviewed. Shortcomings of these methods are explained. Current research topics to improve code reliability and problems encountered in fuel rod behavior modeling are presented

  7. Unified model of current-hadronic interactions. II

    International Nuclear Information System (INIS)

    Moffat, J.W.; Wright, A.C.D.

    1975-01-01

    An analytic model of current-hadronic interactions is used to make predictions which are compared with recent data for vector-meson electroproduction and for the spin density matrix of photoproduced rho 0 mesons. The rho 0 and ω electroproduction cross sections are predicted to behave differently as the mass of the virtual photon varies; the diffraction peak broadens with increasing -q 2 at fixed ν and narrows with increasing energy. The predicted rho 0 density matrix elements do not possess the approximate s-channel helicity conservation seen experimentally. The model is continued to the inclusive electron-positron annihilation region, where parameter-free predictions are given for the inclusive prosess e + + e - → p + hadrons. The annihilation structure functions are found to have nontrivial scale-invariance limits. By using total cross-section data for e + e - annihilation into hardrons, we predict the mean multiplicity for the production of nucleons

  8. A qualitative model for strategic analysis of organizations. Application and alternative proposal on a study case

    Directory of Open Access Journals (Sweden)

    Santiago Ferro Moreno

    2015-12-01

    Full Text Available The strategic analysis of organizations is based on the internal and external environments, in order to identify positive and negative variables and factors. The interrelation and timing of these strategic forces are essential to create alternative solutions that tend to achieve the organizational objectives.The normative prospective has theorical and methodological foundations to create a desired future and from it, be able to identify impelling and restraining forces that have influence on the particular problematic situation (go from the current situation to a better one in a certain time.The aim of this article is to analyze on a strategic way a real case with a normative-prospective model that considers the temporal dynamics of the factors impact and variables in time allowing to suggest alternative solutions.Semi-structured interviews were performed with all the employees of this case and structured observations and workshops with the commercial and general management.In consequence, with the results, the desired, current and improved situations were built. Additionally, forces were identified classified and appreciated and lastly solutions were suggested. With the proposed prospective method, alternative solutions could be constructed in order to settle temporary organizational objectives. No constraints were found to use the current method in other cases.Keywords: Strategic forces, Normative prospective, Problematic situations, Strategies

  9. A proposed simulation optimization model framework for emergency department problems in public hospital

    Science.gov (United States)

    Ibrahim, Ireen Munira; Liong, Choong-Yeun; Bakar, Sakhinah Abu; Ahmad, Norazura; Najmuddin, Ahmad Farid

    2015-12-01

    The Emergency Department (ED) is a very complex system with limited resources to support increase in demand. ED services are considered as good quality if they can meet the patient's expectation. Long waiting times and length of stay is always the main problem faced by the management. The management of ED should give greater emphasis on their capacity of resources in order to increase the quality of services, which conforms to patient satisfaction. This paper is a review of work in progress of a study being conducted in a government hospital in Selangor, Malaysia. This paper proposed a simulation optimization model framework which is used to study ED operations and problems as well as to find an optimal solution to the problems. The integration of simulation and optimization is hoped can assist management in decision making process regarding their resource capacity planning in order to improve current and future ED operations.

  10. A proposed wind shift model for the German reactor safety study

    International Nuclear Information System (INIS)

    Aldrich, D.C.; Bayer, A.; Schueckler, M.

    1979-04-01

    To account for hourly wind direction changes, a wind shift model has been proposed. Using hourly recorded wind speed and direction data, the model modifies the angular distribution of radionuclide concentrations calculated by a straightline model, and is intended to better represent the concentrations in areas close to the reactor where potential doses might exceed the threshold level for early fatalities. 115 weather sequences were used, both with and without the proposed wind shift model, to calculate probability distributions for early fatalities. The use of the proposed model results in a reduction of the mean and peak values of that distribution by 36% and 29%, respectively. (orig./HP) [de

  11. High resolution modelling of the North Icelandic Irminger Current (NIIC

    Directory of Open Access Journals (Sweden)

    K. Logemann

    2006-01-01

    Full Text Available The northward inflow of Atlantic Water through Denmark Strait – the North Icelandic Irminger Current (NIIC – is simulated with a numerical model of the North Atlantic and Arctic Ocean. The model uses the technique of adaptive grid refinement which allows a high spatial resolution (1 km horizontal, 10 m vertical around Iceland. The model is used to assess time and space variability of volume and heat fluxes for the years 1997–2003. Passive tracers are applied to study origin and composition of NIIC water masses. The NIIC originates from two sources: the Irminger Current, flowing as part of the sub-polar gyre in 100–500 m depth along the Reykjanes Ridge and the shallow Icelandic coastal current, flowing north-westward on the south-west Icelandic shelf. The ratio of volume flux between the deep and shallow branch is around 2:1. The NIIC continues as a warm and saline branch northward through Denmark Strait where it entrains large amounts of polar water due to the collision with the southward flowing East Greenland Current. After passing Denmark Strait, the NIIC follows the coast line eastward being an important heat source for north Icelandic waters. At least 60% of the temporal temperature variability of north Icelandic waters is caused by the NIIC. The NIIC volume and heat transport is highly variable and depends strongly on the wind field north-east of Denmark Strait. Daily means can change from 1 Sv eastward to 2 Sv westward within a few days. Highest monthly mean transport rates occur in summer when winds from north are weak, whereas the volume flux is reduced by around 50% in winter. Summer heat flux rates can be even three times higher than in winter. The simulation also shows variability on the interannual scale. In particular weak winds from north during winter 2002/2003 combined with mild weather conditions south of Iceland led to anomalous high NIIC volume (+40% and heat flux (+60% rates. In this period, simulated north Icelandic

  12. Levitation of current carrying states in the lattice model for the integer quantum Hall effect.

    Science.gov (United States)

    Koschny, T; Potempa, H; Schweitzer, L

    2001-04-23

    The disorder driven quantum Hall to insulator transition is investigated for a two-dimensional lattice model. The Hall conductivity and the localization length are calculated numerically near the transition. For uncorrelated and weakly correlated disorder potentials the current carrying states are annihilated by the negative Chern states originating from the band center. In the presence of correlated disorder potentials with correlation length larger than approximately half the lattice constant the floating up of the critical states in energy without merging is observed. This behavior is similar to the levitation scenario proposed for the continuum model.

  13. Neutral current in reduced minimal 3-3-1 model

    International Nuclear Information System (INIS)

    Vu Thi Ngoc Huyen; Hoang Ngoc Long; Tran Thanh Lam; Vo Quoc Phong

    2014-01-01

    This work is devoted for gauge boson sector of the recently proposed model based on SU(3) C ⊗SU(3) L ⊗ U(1) X group with minimal content of leptons and Higgs. The limits on the masses of the bilepton gauge bosons and on the mixing angle among the neutral ones are deduced. Using the Fritzsch anzats on quark mixing, we show that the third family of quarks should be different from the first two. We obtain a lower bound on mass of the new heavy neutral gauge boson as 4.032 TeV. Using data on branching decay rates of the Z boson, we can fix the limit to the Z and Z' mixing angle φ as - 0.001 ≤ φ ≤ 0.0003. (author)

  14. Proposal for operator's mental model using the concept of multilevel flow modeling

    International Nuclear Information System (INIS)

    Yoshimura, Seiichi; Takano, Kenichi; Sasou, Kunihide

    1995-01-01

    It is necessary to analyze an operator's thinking process and a operator team's intension forming process for preventing human errors in a highly advanced huge system like a nuclear power plant. Central Research Institute of Electric Power Industry is promoting a research project to establish human error prevention countermeasures by modeling the thinking and intension forming process. The important is the future prediction and the cause identification when abnormal situations occur in a nuclear power plant. The concept of Multilevel Flow Modeling (MFM) seems to be effective as an operator's mental model which performs the future prediction and the cause identification. MFM is a concept which qualitatively describes the plant functions by energy and mass flows and also describes the plant status by breaking down the targets in a hierarchical manner which a plant should achieve. In this paper, an operator's mental model using the concept of MFM was proposed and a nuclear power plant diagnosis support system using MFM was developed. The system evaluation test by personnel who have operational experience in nuclear power plants revealed that MFM was superior in the future prediction and the cause identification to a traditional nuclear power plant status display system which used mimics and trends. MFM proved to be useful as an operator's mental model by the test. (author)

  15. Supporting Current Energy Conversion Projects through Numerical Modeling

    Science.gov (United States)

    James, S. C.; Roberts, J.

    2016-02-01

    The primary goals of current energy conversion (CEC) technology being developed today are to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the environment surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. These alterations pose potential stressors to numerous environmental receptors. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array so that these potential impacts can be evaluated. Moreover, this software can be used to optimize array layouts that yield the least changes to the environmental (i.e., hydrodynamics, sediment dynamics, and water quality). Through model calibration exercises, simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains. The Delft3D modeling tool facilitates siting of CEC projects through optimization of array layouts and evaluation of potential environmental effect all while provide a common "language" for academics, industry, and regulators to be able to discuss the implications of marine renewable energy projects. Given the enormity of any full-scale marine renewable energy project, it necessarily falls to modeling to evaluate how array operations must be addressed in an environmental impact statement in a way that engenders confidence in the assessment of the CEC array to minimize environmental effects.

  16. Current Translational Research and Murine Models For Duchenne Muscular Dystrophy

    Science.gov (United States)

    Rodrigues, Merryl; Echigoya, Yusuke; Fukada, So-ichiro; Yokota, Toshifumi

    2016-01-01

    Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder characterized by progressive muscle degeneration. Mutations in the DMD gene result in the absence of dystrophin, a protein required for muscle strength and stability. Currently, there is no cure for DMD. Since murine models are relatively easy to genetically manipulate, cost effective, and easily reproducible due to their short generation time, they have helped to elucidate the pathobiology of dystrophin deficiency and to assess therapies for treating DMD. Recently, several murine models have been developed by our group and others to be more representative of the human DMD mutation types and phenotypes. For instance, mdx mice on a DBA/2 genetic background, developed by Fukada et al., have lower regenerative capacity and exhibit very severe phenotype. Cmah-deficient mdx mice display an accelerated disease onset and severe cardiac phenotype due to differences in glycosylation between humans and mice. Other novel murine models include mdx52, which harbors a deletion mutation in exon 52, a hot spot region in humans, and dystrophin/utrophin double-deficient (dko), which displays a severe dystrophic phenotype due the absence of utrophin, a dystrophin homolog. This paper reviews the pathological manifestations and recent therapeutic developments in murine models of DMD such as standard mdx (C57BL/10), mdx on C57BL/6 background (C57BL/6-mdx), mdx52, dystrophin/utrophin double-deficient (dko), mdxβgeo, Dmd-null, humanized DMD (hDMD), mdx on DBA/2 background (DBA/2-mdx), Cmah-mdx, and mdx/mTRKO murine models. PMID:27854202

  17. Shigella vaccine development: prospective animal models and current status.

    Science.gov (United States)

    Kim, Yeon-Jeong; Yeo, Sang-Gu; Park, Jae-Hak; Ko, Hyun-Jeong

    2013-01-01

    Shigella was first discovered in 1897 and is a major causative agent of dysenteric diarrhea. The number of affected patients has decreased globally because of improved sanitary conditions; however, Shigella still causes serious problems in many subjects, including young children and the elderly, especially in developing countries. Although antibiotics may be effective, a vaccine would be the most powerful solution to combat shigellosis because of the emergence of drug-resistant strains. However, the development of a vaccine is hampered by several problems. First, there is no suitable animal model that can replace human-based studies for the investigation of the in vivo mechanisms of Shigella vaccines. Mouse, guinea pig, rat, rabbit, and nonhuman primates could be used as models for shigellosis, but they do not represent human shigellosis and each has its own weaknesses. However, a recent murine model based on peritoneal infection with virulent S. flexneri 2a is promising. Moreover, although the inflammatory responses and mechanisms such as pathogenassociated molecular patterns and danger-associated molecular patterns have been studied, the pathology and immunology of Shigella are still not clearly defined. Despite these obstacles, many vaccine candidates have been developed, including live attenuated, killed whole cells, conjugated, and subunit vaccines. The development of Shigella vaccines also demands considerations of the cost, routes of administration, ease of storage (stability), cross-reactivity, safety, and immunogenicity. The main aim of this review is to provide a detailed introduction to the many promising vaccine candidates and animal models currently available, including the newly developed mouse model.

  18. PUBLIC ADMINISTRATION: MODERNIZING THE CURRENT MODEL OF STATE MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Evgenii V. Ohotskii

    2014-01-01

    Full Text Available Applying the method of retrospective analysis the article deals with the process of forming the scientific fundamentals and the search by the international community of effective and adequate to the current stage of social development public administration system. The author attempts to analyze, in a number of cases in terms of models, features of public administration systems at different stages of historical development, drawing attention to reasons why the Soviet model of public administration did not manage to meet competition, did not provide the required social effect and as a natural result suffered a defeat in the global confrontation between the two social systems. Current models and theoretical concepts of public administration, especially the "new public administration", which became scientific basis for administrative reforms implemented in many countries, are the particular subject of scientific analysis. The author draws attention to major comprehensive characteristics of modern state public administration: making it impossible to absolutize principles of traditional hierarchy system of forced administration; globalization - gradual destruction of boundaries between national and international levels of administration, the growing role of supranational subjects of administration relations; informatization - increasing importance of information and communication technologies and of political networks: development of civil society, especially political parties and non-governmental organizations, growing public involvement in discussion and adoption of the most important administrative decisions; making the state policy more pluralistic and which will result in the formation of nonlinear - humanistic social consciousness as the intellectual basis of modern social governance. The author's position is that Russia is yet to solve the issue of choosing a public administration model that would be effective for further administrative

  19. The current Russian model of social development, and economic growth

    Directory of Open Access Journals (Sweden)

    V V Paramonov

    2016-12-01

    Full Text Available Although the Article 7 of the Constitution of Russia adopted in 1993 defines the country as a social state, the contemporary social and economic situation is significantly different from this declaration. The author considers the current situation focusing on the foundations of the welfare state. The indicators of social inequality and stratification that allow to identify the country as a social state prove the widening gap between the rich and poor. In recent years, nothing has been done to achieve the more equitable distribution of income and national wealth, which led to the further growth of social inequality exceeding the global indices. The author believes that the high level of social inequality negatively affects the economic growth. Based on the studies of Russian scientists he concludes that equal distribution of income provides higher rates of economic growth and prosperity of the country. The modified theory of the factors of production explains this interconnection, and adds a few more factors, including such a specific resource as sales market, to three factors introduced by J.B. Say at the beginning of the XIX century. The huge social inequality and, consequently, a significant number of the poor deprive the country of such an important resource. To change the situation, the author proposes to return to the progressive tax scale and introduce the zero rate of income tax for the poorest groups in order to create prerequisites for the growth of consumer demand under the economic crisis.

  20. Lessons from the Current Japanese Triple Helix Model

    Directory of Open Access Journals (Sweden)

    Mitsuaki Hosono

    2012-12-01

    Full Text Available Since mid-1990s, the Japanese government has encouraged university-industry collaboration to foster innovations for economic growth. Learning from the American licensing model of technology transfer, Japanese Bay-Dole Act and TLO (Technology Licensing Organization Act were enacted in late 1990s. In addition, the corporatization of Japanese National Universities (JNUs in 2004 spurred their technology-transfer activities to obtain external funds. As a result, more than 50 TLOs has been established since FY1998, and also the number of patent application and licensed patents were increased at JUNs rapidly after FY2004. However, the licensing income has been stayed poor and some of TLOs were abolished. There are few evidences that the introduction of licensing model of technology transfer into Japan could contribute to innovation properly. Therefore, this study will try to clarify if licensing model of technology transfer work in Japan by analyzing the Japanese National University (JNU patent. There are 20,485 applied patent, which invented by JNU’s researcher(s from FY2004 to 2007. 38% of them were applied by solely by JNUs and 52% were by JNU and Private Firms etc. In the Japanese Patent Act, jointly applied patents are not licensed to the third party without the consent of co-applicant(s. Hence, more than half of the patent invented by JNU researchers is not basically used for patent licensing. Consequently, JNUs and TLOs face difficulties in patent licensing under the current Patent Act.

  1. Modeling photo-desorption in high current storage rings

    International Nuclear Information System (INIS)

    Barletta, W.A.

    1991-01-01

    High luminosity flavor factories are characterized by high fluxes of synchrotron radiation that lead to thermal management difficulties. The associated photo-desorption from the vacuum chamber walls presents an additional design challenge, providing a vacuum system suitable for maintaining acceptable beam-gas lifetimes and low background levels of scattered radiation in the detector. Achieving acceptable operating pressures (1-10 nTorr) with practical pumping schemes requires the use of materials with low photodesorption efficiency operating in a radiation environment beyond that of existing storage rings. Extrapolating the existing photo-desorption data base to the design requirements of high luminosity colliders requires a physical model of the differential cleaning in the vacuum chamber. The authors present a simple phenomenological model of photodesorption that includes effects of dose dependence and diffuse photon reflection to compute the leveling of gas loads in beamlines of high current storage rings that typify heavy flavor factories. This model is also used to estimate chamber commissioning times

  2. Proton Therapy Expansion Under Current United States Reimbursement Models

    Energy Technology Data Exchange (ETDEWEB)

    Kerstiens, John [Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Johnstone, Peter A.S., E-mail: pajohnst@iupui.edu [Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States)

    2014-06-01

    Purpose: To determine whether all the existing and planned proton beam therapy (PBT) centers in the United States can survive on a local patient mix that is dictated by insurers, not by number of patients. Methods and Materials: We determined current and projected cancer rates for 10 major US metropolitan areas. Using published utilization rates, we calculated patient percentages who are candidates for PBT. Then, on the basis of current published insurer coverage policies, we applied our experience of what would be covered to determine the net number of patients for whom reimbursement is expected. Having determined the net number of covered patients, we applied our average beam delivery times to determine the total number of minutes needed to treat that patient over the course of their treatment. We then calculated our expected annual patient capacity per treatment room to determine the appropriate number of treatment rooms for the area. Results: The population of patients who will be both PBT candidates and will have treatments reimbursed by insurance is significantly smaller than the population who should receive PBT. Coverage decisions made by insurers reduce the number of PBT rooms that are economically viable. Conclusions: The expansion of PBT centers in the US is not sustainable under the current reimbursement model. Viability of new centers will be limited to those operating in larger regional metropolitan areas, and few metropolitan areas in the US can support multiple centers. In general, 1-room centers require captive (non–PBT-served) populations of approximately 1,000,000 lives to be economically viable, and a large center will require a population of >4,000,000 lives. In areas with smaller populations or where or a PBT center already exists, new centers require subsidy.

  3. Cardiovascular diseases induced by low level ionizing radiation. Current status and proposal of future directions of the biological studies

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Nomura, Takaharu; Ishii, Keiichiro

    2013-01-01

    In the publication on tissue reactions of the International Commission on Radiological Protection (ICRP), the risk of cardiovascular diseases (CVD) was calculated based on linear non-threshold model, without taking account of dose-rate effect. To evaluate the validity of this estimation, we analyzed recent epidemiological and biological findings on CVD at low dose or low dose-rate. Though epidemiological data suggested that radiation would have a causal association with CVD by inducing atherosclerosis, it was limited by heterogeneity among studies, and the contribution of other pathways was also suggested. As biological mechanisms, inflammation is considered as the critical factor of radiation induced CVD. However, the inflammatory responses at low dose were inconsistent among studies, and there were few data at low dose-rate. Furthermore, because those responses were transient, it was very difficult to link them to CVD with long latency. We proposed a concept for the analysis of these long latency diseases by focusing the premonitory symptoms of CVD which could be affected by radiation. As the premonitory symptoms recruitment of white blood cells to inflamed blood vessels and/or tissues would have the highest priority to investigate. To elucidate the dose-rate effect and reflect the results on the radiological protection, it would be important to examine the premonitory symptoms after long term exposure mimicking the actual situation, such as chronic exposure or fractionated exposure of very small dose. (author)

  4. [Disease prevention in the elderly: misconceptions in current models].

    Science.gov (United States)

    Veras, Renato Peixoto

    2012-10-01

    The Brazilian population is aging significantly within a context of gradual improvement in the country's social and economic indicators. Increased longevity leads to increased use of health services, pressuring the public and social welfare health services, generating higher costs, and jeopardizing the system's sustainability. The alternative to avoid overburdening the system is to invest in policies for disease prevention, stabilization of chronic diseases, and maintenance of functional capacity. The current article aims to analyze the difficulties in implementing preventive programs and the reasons for the failure of various programs in health promotion, prevention, and management of chronic diseases in the elderly. There can be no solution to the crisis in financing and restructuring the health sector without implementing a preventive logic. Scientific research has already correctly identified the risk factors for the elderly population, but this is not enough. We must use such knowledge to promote the necessary transition from a healthcare-centered model to a preventive one.

  5. Optimizing nitrogen fertilizer use: Current approaches and simulation models

    International Nuclear Information System (INIS)

    Baethgen, W.E.

    2000-01-01

    Nitrogen (N) is the most common limiting nutrient in agricultural systems throughout the world. Crops need sufficient available N to achieve optimum yields and adequate grain-protein content. Consequently, sub-optimal rates of N fertilizers typically cause lower economical benefits for farmers. On the other hand, excessive N fertilizer use may result in environmental problems such as nitrate contamination of groundwater and emission of N 2 O and NO. In spite of the economical and environmental importance of good N fertilizer management, the development of optimum fertilizer recommendations is still a major challenge in most agricultural systems. This article reviews the approaches most commonly used for making N recommendations: expected yield level, soil testing and plant analysis (including quick tests). The paper introduces the application of simulation models that complement traditional approaches, and includes some examples of current applications in Africa and South America. (author)

  6. Wall conditioning for ITER: Current experimental and modeling activities

    Energy Technology Data Exchange (ETDEWEB)

    Douai, D., E-mail: david.douai@cea.fr [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Kogut, D. [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Wauters, T. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Brezinsek, S. [FZJ, Institut für Energie- und Klimaforschung Plasmaphysik, 52441 Jülich (Germany); Hagelaar, G.J.M. [Laboratoire Plasma et Conversion d’Energie, UMR5213, Toulouse (France); Hong, S.H. [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lomas, P.J. [CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Lyssoivan, A. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Nunes, I. [Associação EURATOM-IST, Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa (Portugal); Pitts, R.A. [ITER International Organization, F-13067 St. Paul lez Durance (France); Rohde, V. [Max-Planck-Institut für Plasmaphysik, 85748 Garching (Germany); Vries, P.C. de [ITER International Organization, F-13067 St. Paul lez Durance (France)

    2015-08-15

    Wall conditioning will be required in ITER to control fuel and impurity recycling, as well as tritium (T) inventory. Analysis of conditioning cycle on the JET, with its ITER-Like Wall is presented, evidencing reduced need for wall cleaning in ITER compared to JET–CFC. Using a novel 2D multi-fluid model, current density during Glow Discharge Conditioning (GDC) on the in-vessel plasma-facing components (PFC) of ITER is predicted to approach the simple expectation of total anode current divided by wall surface area. Baking of the divertor to 350 °C should desorb the majority of the co-deposited T. ITER foresees the use of low temperature plasma based techniques compatible with the permanent toroidal magnetic field, such as Ion (ICWC) or Electron Cyclotron Wall Conditioning (ECWC), for tritium removal between ITER plasma pulses. Extrapolation of JET ICWC results to ITER indicates removal comparable to estimated T-retention in nominal ITER D:T shots, whereas GDC may be unattractive for that purpose.

  7. Experimental modeling of eddy currents and deflections for tokamak limiters

    International Nuclear Information System (INIS)

    Hua, T.Q.; Knott, M.J.; Turner, L.R.; Wehrle, R.B.

    1986-01-01

    In this study, experiments were performed to investigate deflection, current, and material stress in cantilever beams with the Fusion ELectromagnetic Induction eXperiment (FELIX) at the Argonne National Laboratory. Since structures near the plasma are typically cantilevered, the beams provide a good model for the limiter blades of a tokamak fusion reactor. The test pieces were copper, aluminum, phosphor bronze, and brass cantilever beams, clamped rigidly at one end with a nonconducting support frame inside the FELIX test volume. The primary data recorded as functions of time were the beam deflection measured with a noncontact electro-optical device, the total eddy current measured with a Rogowski coil and linking through a central hole in the beam, and the material stress extracted from strain gauges. Measurements of stress and deflection were taken at selected positions along the beam. The extent of the coupling effect depends on several factors. These include the size, the electrical and mechanical properties of the beam, segmenting of the beam, the decay rate of the dipole field, and the strength of the solenoid field

  8. Current leakage for low altitude satellites: modeling applications

    International Nuclear Information System (INIS)

    Konradi, A.; Mccoy, J.E.; Garriott, O.K.

    1979-01-01

    To simulate the behavior of a high voltage solar cell array in the ionospheric plasma environment, the large (90 ft x 55 ft diameter) vacuum chamber was used to measure the high-voltage plasma interactions of a 3 ft x 30 ft conductive panel. The chamber was filled with nitrogen and argon plasma at electron densities of up to 1,000,000 per cu cm. Measurements of current flow to the plasma were made in three configurations: (a) with one end of the panel grounded, (b) with the whole panel floating while a high bias was applied between the ends of the panel, and (c) with the whole panel at high negative voltage with respect to the chamber walls. The results indicate that a simple model with a constant panel conductivity and plasma resistance can adequately describe the voltage distribution along the panel and the plasma current flow. As expected, when a high potential difference is applied to the panel ends more than 95% of the panel floats negative with respect to the plasma

  9. Current density distribution during disruptions and sawteeth in a simple model of plasma current in a tokamak

    International Nuclear Information System (INIS)

    Stefanovskii, A. M.

    2011-01-01

    The processes that are likely to accompany discharge disruptions and sawteeth in a tokamak are considered in a simple plasma current model. The redistribution of the current density in plasma is supposed to be primarily governed by the onset of the MHD-instability-driven turbulent plasma mixing in a finite region of the current column. For different disruption conditions, the variation in the total plasma current (the appearance of a characteristic spike) is also calculated. It is found that the numerical shape and amplitude of the total current spikes during disruptions approximately coincide with those measured in some tokamak experiments. Under the assumptions adopted in the model, the physical mechanism for the formation of the spikes is determined. The mechanism is attributed to the diffusion of the negative current density at the column edge into the zero-conductivity region. The numerical current density distributions in the plasma during the sawteeth differ from the literature data.

  10. Atlantis model outputs - Developing end-to-end models of the California Current Large Marine Ecosystem

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this project is to develop spatially discrete end-to-end models of the California Current LME, linking oceanography, biogeochemistry, food web...

  11. Proposal for the momentum-resolved and time-resolved optical measurement of the current distribution in semiconductors.

    Science.gov (United States)

    Liu, Jiang-Tao; Su, Fu-Hai; Deng, Xin-Hua; Wang, Hai

    2012-05-21

    The two-color optical coherence absorption spectrum (QUIC-AB) of semiconductors in the presence of a charge current is investigated. We find that the QUIC-AB depends strongly not only on the amplitude of the electron current but also on the direction of the electron current. Thus, the amplitude and the angular distribution of current in semiconductors can be detected directly in real time with the QUIC-AB.

  12. Subthreshold Current and Swing Modeling of Gate Underlap DG MOSFETs with a Source/Drain Lateral Gaussian Doping Profile

    Science.gov (United States)

    Singh, Kunal; Kumar, Sanjay; Goel, Ekta; Singh, Balraj; Kumar, Mirgender; Dubey, Sarvesh; Jit, Satyabrata

    2017-01-01

    This paper proposes a new model for the subthreshold current and swing of the short-channel symmetric underlap ultrathin double gate metal oxide field effect transistors with a source/drain lateral Gaussian doping profile. The channel potential model already reported earlier has been utilized to formulate the closed form expression for the subthreshold current and swing of the device. The effects of the lateral straggle and geometrical parameters such as the channel length, channel thickness, and oxide thickness on the off current and subthreshold slope have been demonstrated. The devices with source/drain lateral Gaussian doping profiles in the underlap structure are observed to be highly resistant to short channel effects while improving the current drive. The proposed model is validated by comparing the results with the numerical simulation data obtained by using the commercially available ATLAS™, a two-dimensional (2-D) device simulator from SILVACO.

  13. Capabilities of current wildfire models when simulating topographical flow

    Science.gov (United States)

    Kochanski, A.; Jenkins, M.; Krueger, S. K.; McDermott, R.; Mell, W.

    2009-12-01

    Accurate predictions of the growth, spread and suppression of wild fires rely heavily on the correct prediction of the local wind conditions and the interactions between the fire and the local ambient airflow. Resolving local flows, often strongly affected by topographical features like hills, canyons and ridges, is a prerequisite for accurate simulation and prediction of fire behaviors. In this study, we present the results of high-resolution numerical simulations of the flow over a smooth hill, performed using (1) the NIST WFDS (WUI or Wildland-Urban-Interface version of the FDS or Fire Dynamic Simulator), and (2) the LES version of the NCAR Weather Research and Forecasting (WRF-LES) model. The WFDS model is in the initial stages of development for application to wind flow and fire spread over complex terrain. The focus of the talk is to assess how well simple topographical flow is represented by WRF-LES and the current version of WFDS. If sufficient progress has been made prior to the meeting then the importance of the discrepancies between the predicted and measured winds, in terms of simulated fire behavior, will be examined.

  14. Current amplification models of sensorineurall and conductive hearing loss

    Directory of Open Access Journals (Sweden)

    Ostojić Sanja

    2012-01-01

    Full Text Available The main function of a hearing aid is to improve auditory and language abilities of hearing impaired users. The amplification model has to be adapted according to age, degree and type of hearing loss. The goal of this paper is to analyze the current amplification models of sensorineural and conductive hearing loss which can provide a high quality of speech perception and sounds at any degree of hearing loss. The BAHA is a surgically implantable system for treatment of conductive hearing loss that works through direct bone conduction. BAHA is used to help people with chronic ear infections, congenital external auditory canal atresia and single sided deafness who cannot benefit from conventional hearing aids. The last generation of hearing aid for sensorineural hearing loss is cochlear implant. Bimodal amplification improves binaural hearing. Hearing aids alone do not make listening easier in all situations. The things that can interfere with listening are background noises, distance from a sound and reverberation or echo. The device used most often today is the Frequency Modulated (FM system.

  15. PTM Modeling of Dredged Suspended Sediment at Proposed Polaris Point and Ship Repair Facility CVN Berthing Sites - Apra Harbor, Guam

    Science.gov (United States)

    2017-09-01

    sedimentation outside of the channel footprint. For example, dredging near the edge of the footprint can be confined to time periods when tidal currents...Cases 1 or 2 due to the lower loss rate. Sedimentation rates outside the channel prism are further reduced because all sediment is introduced in the...ER D C/ CH L TR -1 7- 16 PTM Modeling of Dredged Suspended Sediment at Proposed Polaris Point and Ship Repair Facility CVN Berthing

  16. Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Mesbahus Saleheen

    2016-05-01

    Full Text Available A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ organic solar cells is developed by considering Shockley-Read-Hall (SRH recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs, carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun’s model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The overall net current is calculated considering the actual solar spectrum. The mathematical models are verified by comparing the model calculations with various published experimental results. We analyze the effects of the contact properties, blend compositions, charge carrier transport properties (carrier mobility and lifetime, and cell design on the current-voltage characteristics. The power conversion efficiency of BHJ organic solar cells mostly depends on electron transport properties of the acceptor layer. The results of this paper indicate that improvement of charge carrier transport (both mobility and lifetime and dissociation of bound EHPs in organic blend are critically important to increase the power conversion efficiency of the BHJ solar cells.

  17. Dust Composition in Climate Models: Current Status and Prospects

    Science.gov (United States)

    Pérez García-Pando, C.; Miller, R. L.; Perlwitz, J. P.; Kok, J. F.; Scanza, R.; Mahowald, N. M.

    2015-12-01

    Mineral dust created by wind erosion of soil particles is the dominant aerosol by mass in the atmosphere. It exerts significant effects on radiative fluxes, clouds, ocean biogeochemistry, and human health. Models that predict the lifecycle of mineral dust aerosols generally assume a globally uniform mineral composition. However, this simplification limits our understanding of the role of dust in the Earth system, since the effects of dust strongly depend on the particles' physical and chemical properties, which vary with their mineral composition. Hence, not only a detailed understanding of the processes determining the dust emission flux is needed, but also information about its size dependent mineral composition. Determining the mineral composition of dust aerosols is complicated. The largest uncertainty derives from the current atlases of soil mineral composition. These atlases provide global estimates of soil mineral fractions, but they are based upon massive extrapolation of a limited number of soil samples assuming that mineral composition is related to soil type. This disregards the potentially large variability of soil properties within each defined soil type. In addition, the analysis of these soil samples is based on wet sieving, a technique that breaks the aggregates found in the undisturbed parent soil. During wind erosion, these aggregates are subject to partial fragmentation, which generates differences on the size distribution and composition between the undisturbed parent soil and the emitted dust aerosols. We review recent progress on the representation of the mineral and chemical composition of dust in climate models. We discuss extensions of brittle fragmentation theory to prescribe the emitted size-resolved dust composition, and we identify key processes and uncertainties based upon model simulations and an unprecedented compilation of observations.

  18. Current collapse modeling in AlGaN/GaN HEMT using small signal equivalent circuit for high power application

    Science.gov (United States)

    Nirmal, D.; Arivazhagan, L.; Fletcher, A. S. Augustine; Ajayan, J.; Prajoon, P.

    2018-01-01

    In this paper, the drain current collapse in AlGaN/GaN High Electron Mobility Transistor (HEMT) with field plate engineering is investigated. A small signal equivalent circuit of AlGaN/GaN HEMT is developed and a new drain current model is derived. This model is useful to correlate the impact of intrinsic capacitance and conductance on drain current collapse. The proposed device suppressed the current collapse phenomena by 10% compared with the conventional AlGaN/GaN HEMT. Moreover, the DC characteristics of the simulated device shows a drain current of 900 mA/mm, breakdown voltage of 291 V and transconductance of 175 mS/mm. Besides, the intrinsic capacitance and conductance parameters are extracted and its impact on drain current is analysed. Finally, the simulation results obtained were in compliance with the derived mathematical model of AlGaN/GaN HEMT.

  19. Blended learning in anesthesia education: current state and future model.

    Science.gov (United States)

    Kannan, Jaya; Kurup, Viji

    2012-12-01

    Educators in anesthesia residency programs across the country are facing a number of challenges as they attempt to integrate blended learning techniques in their curriculum. Compared with the rest of higher education, which has made advances to varying degrees in the adoption of online learning anesthesiology education has been sporadic in the active integration of blended learning. The purpose of this review is to discuss the challenges in anesthesiology education and relevance of the Universal Design for Learning framework in addressing them. There is a wide chasm between student demand for online education and the availability of trained faculty to teach. The design of the learning interface is important and will significantly affect the learning experience for the student. This review examines recent literature pertaining to this field, both in the realm of higher education in general and medical education in particular, and proposes the application of a comprehensive learning model that is new to anesthesiology education and relevant to its goals of promoting self-directed learning.

  20. A New Proposed Cost Model for List Accessing Problem using Buffering

    OpenAIRE

    Mohanty, Rakesh; Bhoi, Seetaya; Tripathy, Sasmita

    2011-01-01

    There are many existing well known cost models for the list accessing problem. The standard cost model developed by Sleator and Tarjan is most widely used. In this paper, we have made a comprehensive study of the existing cost models and proposed a new cost model for the list accessing problem. In our proposed cost model, for calculating the processing cost of request sequence using a singly linked list, we consider the access cost, matching cost and replacement cost. The cost of processing a...

  1. 3-Dimensional Flow Modeling of a Proposed Hanford Waste Treatment Plant Ion-Exchange Column Design

    International Nuclear Information System (INIS)

    ALEMAN, SEBASTIAN

    2002-01-01

    Historically, it has been assumed that the inlet and outlet low activity waste plenums would be designed such that a nearly uniform velocity profile would be maintained at every axial cross-section (i.e., providing nearly 100 percent use of the resin bed). With this proposed design, we see a LAW outlet distributor that results in significant non-axial velocity gradients in the bottom regions of the bed with the potential to reduce the effectiveness'' of the overall resin bed. The magnitude of this efficiency reduction depends upon how far up-gradient of the LAW outlet these non-axial velocities persist and to what extent a ''dead-zone'' is established beneath the LAW outlet. This can impact loading and elution performance of the ion-exchange facility. Currently, no experimental studies are planned. The primary objective of this work was, through modeling, to assess the fluid dynamic impact on ''effective'' resin volume of the full-scale column based on its normal operation using a recently proposed LAW outlet distributor. The analysis effort was limited to 3-D flow only analyses (i.e., no follow on transport analyses) with 3-D particle tracking to approximate the impact that a nonaxial velocity profile would have on bed ''effectiveness''. Additional analyses were performed to estimate under nominal operating conditions the thermal temperature rise across a loaded resin bed and within its particles. Hydrogen bubble formation is not considered in the heat transfer analysis or in the determination of minimum flowrate. All modeling objectives were met

  2. Alfven Wave Reflection Model of Field-Aligned Currents at Mercury

    Science.gov (United States)

    Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James

    2010-01-01

    An Alfven Wave Reflection (AWR) model is proposed that provides closure for strong field-aligned currents (FACs) driven by the magnetopause reconnection in the magnetospheres of planets having no significant ionospheric and surface electrical conductance. The model is based on properties of the Alfven waves, generated at high altitudes and reflected from the low-conductivity surface of the planet. When magnetospheric convection is very slow, the incident and reflected Alfven waves propagate along approximately the same path. In this case, the net field-aligned currents will be small. However, as the convection speed increases. the reflected wave is displaced relatively to the incident wave so that the incident and reflected waves no longer compensate each other. In this case, the net field-aligned current may be large despite the lack of significant ionospheric and surface conductivity. Our estimate shows that for typical solar wind conditions at Mercury, the magnitude of Region 1-type FACs in Mercury's magnetosphere may reach hundreds of kilo-Amperes. This AWR model of field-aligned currents may provide a solution to the long-standing problem of the closure of FACs in the Mercury's magnetosphere. c2009 Elsevier Inc. All rights reserved.

  3. Modelling Marine Sediment Biogeochemistry: Current Knowledge Gaps, Challenges, and Some Methodological Advice for Advancement

    Directory of Open Access Journals (Sweden)

    Gennadi Lessin

    2018-02-01

    Full Text Available The benthic environment is a crucial component of marine systems in the provision of ecosystem services, sustaining biodiversity and in climate regulation, and therefore important to human society. With the contemporary increase in computational power, model resolution and technological improvements in quality and quantity of benthic data, it is necessary to ensure that benthic systems are appropriately represented in coupled benthic-pelagic biogeochemical and ecological modelling studies. In this paper we focus on five topical challenges related to various aspects of modelling benthic environments: organic matter reactivity, dynamics of benthic-pelagic boundary layer, microphytobenthos, biological transport and small-scale heterogeneity, and impacts of episodic events. We discuss current gaps in their understanding and indicate plausible ways ahead. Further, we propose a three-pronged approach for the advancement of benthic and benthic-pelagic modelling, essential for improved understanding, management and prediction of the marine environment. This includes: (A development of a traceable and hierarchical framework for benthic-pelagic models, which will facilitate integration among models, reduce risk of bias, and clarify model limitations; (B extended cross-disciplinary approach to promote effective collaboration between modelling and empirical scientists of various backgrounds and better involvement of stakeholders and end-users; (C a common vocabulary for terminology used in benthic modelling, to promote model development and integration, and also to enhance mutual understanding.

  4. Competency-Based University Undergraduate Teaching Management: Proposal for a Conceptual Model

    Directory of Open Access Journals (Sweden)

    Rodolfo Schmal

    2005-12-01

    Full Text Available The human resources societies and their organizations can count on are more and more relevant. In that sense, a major challenge faced by universities is to give students the appropriate background to be professionals with the profile the current scenario requires. This article focuses the management of university careers. Historically, many careers have emphasized knowledge, especially abstract knowledge. Today, the trend is to address aspects that reach beyond cognition, and focus the attention in effective competencies that include procedures and attitudes. Such approach allows the opportunity of defining a holistic management of careers, reaching beyond the sheer teaching of disciplines. Concurrently, the availability of information methods and tools will contribute for the definition and implementation of a design process that can work with explicit criteria and transformations. The article proposes a conceptual model to represent the objects, and their attributes and associations that are considered of interest for the management of university teaching under a competency focus. A second stage should implement such model through the construction of an information system that supports the management of corresponding careers.

  5. Drought Duration Biases in Current Global Climate Models

    Science.gov (United States)

    Moon, Heewon; Gudmundsson, Lukas; Seneviratne, Sonia

    2016-04-01

    Several droughts in the recent past are characterized by their increased duration and intensity. In particular, substantially prolonged droughts have brought major societal and economic losses in certain regions, yet climate change projections of such droughts in terms of duration is subject to large uncertainties. This study analyzes the biases of drought duration in state-of-the-art global climate model (GCM) simulations from the 5th phase of Coupled Model Intercomparison Project (CMIP5). Drought durations are defined as negative precipitation anomalies and evaluated with three observation-based datasets in the period of 1901-2010. Large spread in biases of GCMs is commonly found in all regions, with particular strong biases in North East Brazil, Africa, Northern Australia, Central America, Central and Northern Europe, Sahel and Asia. Also in most regions, the interquartile range of bias lies below 0, meaning that the GCMs tend to underestimate drought durations. Meanwhile in some regions such as Western South America, the Amazon, Sahel, West and South Africa, and Asia, considerable inconsistency among the three observation-based datasets were found. These results indicate substantial uncertainties and errors in current GCMs for simulating drought durations as well as a large spread in observation-based datasets, both of which are found to be particularly strong in those regions that are often considered to be hot spots of projected future drying. The underlying sources of these uncertainties need to be identified in further study and will be applied to constrain GCM-based drought projections under climate change.

  6. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2011-01-01

    The widely used cascade speed and torque controllers have a limited control performance in most high power applications due to the low switching frequency of power electronic converters and the convenience to avoid speed overshoots and oscillations for lifetime considerations. Model Predictive...... Direct Current Control (MPDCC) leads to an increase of torque control performance taking into account the discrete nature of inverters but temporary offsets and poor responses to load torque variations are still issues in speed control. A load torque estimator is proposed in this paper in order...

  7. A novel current injection model of PWMSC for control and analysis of power system stability

    Directory of Open Access Journals (Sweden)

    Safari Amin

    2013-01-01

    Full Text Available This paper proposes a novel current injection model of Pulse width Modulation based Series Compensator (PWMSC, as new FACTS controller, for damping of low frequency oscillations. The PWMSC operates as a means of continuous control of the degree of series compensation through the variation of the duty cycle of a train of fixed frequency-pulses. The methodology is tested on the sample single machine power system including PWMSC controller by performing computer simulations for small and large distributions. MATLAB/ Simulink software package was used for the simulations.

  8. Stable explicit coupling of the Yee scheme with a linear current model in fluctuating magnetized plasmas

    International Nuclear Information System (INIS)

    Silva, Filipe da; Pinto, Martin Campos; Després, Bruno; Heuraux, Stéphane

    2015-01-01

    This work analyzes the stability of the Yee scheme for non-stationary Maxwell's equations coupled with a linear current model with density fluctuations. We show that the usual procedure may yield unstable scheme for physical situations that correspond to strongly magnetized plasmas in X-mode (TE) polarization. We propose to use first order clustered discretization of the vectorial product that gives back a stable coupling. We validate the schemes on some test cases representative of direct numerical simulations of X-mode in a magnetic fusion plasma including turbulence

  9. PROPOSED SUITE OF MODELS FOR ESTIMATING DOSE RESULTING FROM EXPOSURES BY THE DERMAL ROUTE

    Science.gov (United States)

    Recent risk assessment guidance emphasizes consideration of mechanistic factors for influencing disposition of a toxicant. To incorporate mechanistic information into risk assessment, a suite of models is proposed for use in characterizing and quantifying dosimetry of toxic age...

  10. Current control design for three-phase grid-connected inverters using a pole placement technique based on numerical models

    OpenAIRE

    Citro, Costantino; Gavriluta, Catalin; Nizak Md, H. K.; Beltran, H.

    2012-01-01

    This paper presents a design procedure for linear current controllers of three-phase grid-connected inverters. The proposed method consists in deriving a numerical model of the converter by using software simulations and applying the pole placement technique to design the controller with the desired performances. A clear example on how to apply the technique is provided. The effectiveness of the proposed design procedure has been verified through the experimental results obtained with ...

  11. An Analytical Analysis of Hydraulic Jump in Triangular Channel: A Proposed Model

    Science.gov (United States)

    Khan, S. A.

    2013-05-01

    The paper presents the theoretical study of hydraulic jump in triangular channel section. Presuming the jump as one dimensional free shear layer with hydrostatic pressure distribution across it and using momentum equation, specific force equation is obtained. Using the specific force equation and eddy viscosity equation, analytical models for sequent depth, dimensionless profile, turbulent shear stress distribution and energy loss for various initial Froude numbers have been obtained. The proposed models for sequent depth and energy loss are also compared with the other developed models. The proposed energy loss model also provides the energy loss at any point along the jump, while this provision is not available in the models of other investigators. Newton-Raphson and Runge-Kutta methods are used for the solution of the proposed model. The outcome of this study can be used in the design of stilling basin floor and side walls on permeable foundations.

  12. Effects of electric current upon catalytic steam reforming of biomass gasification tar model compounds to syngas

    International Nuclear Information System (INIS)

    Tao, Jun; Lu, Qiang; Dong, Changqing; Du, Xiaoze; Dahlquist, Erik

    2015-01-01

    Highlights: • ECR technique was proposed to convert biomass gasification tar model compounds. • Electric current enhanced the reforming efficiency remarkably. • The highest toluene conversion reached 99.9%. • Ni–CeO 2 /γ-Al 2 O 3 exhibited good stability during the ECR performance. - Abstract: Electrochemical catalytic reforming (ECR) technique, known as electric current enhanced catalytic reforming technique, was proposed to convert the biomass gasification tar into syngas. In this study, Ni–CeO 2 /γ-Al 2 O 3 catalyst was prepared, and toluene was employed as the major feedstock for ECR experiments using a fixed-bed lab-scale setup where thermal electrons could be generated and provided to the catalyst. Several factors, including the electric current intensity, reaction temperature and steam/carbon (S/C) ratio, were investigated to reveal their effects on the conversion of toluene as well as the composition of the gas products. Moreover, toluene, two other tar model compounds (benzene and 1-methylnaphthalene) and real tar (tar-containing wastewater) were subjected to the long period catalytic stability tests. All the used catalysts were analyzed to determine their carbon contents. The results indicated that the presence of electric current enhanced the catalytic performance remarkably. The toluene conversion reached 99.9% under the electric current of 4 A, catalytic temperature of 800 °C and S/C ratio of 3. Stable conversion performances of benzene, 1-methylnaphthalene and tar-containing wastewater were also observed in the ECR process. H 2 and CO were the major gas products, while CO 2 and CH 4 were the minor ones. Due to the promising capability, the ECR technique deserves further investigation and application for efficient tar conversion

  13. An improved PSO-SVM model for online recognition defects in eddy current testing

    Science.gov (United States)

    Liu, Baoling; Hou, Dibo; Huang, Pingjie; Liu, Banteng; Tang, Huayi; Zhang, Wubo; Chen, Peihua; Zhang, Guangxin

    2013-12-01

    Accurate and rapid recognition of defects is essential for structural integrity and health monitoring of in-service device using eddy current (EC) non-destructive testing. This paper introduces a novel model-free method that includes three main modules: a signal pre-processing module, a classifier module and an optimisation module. In the signal pre-processing module, a kind of two-stage differential structure is proposed to suppress the lift-off fluctuation that could contaminate the EC signal. In the classifier module, multi-class support vector machine (SVM) based on one-against-one strategy is utilised for its good accuracy. In the optimisation module, the optimal parameters of classifier are obtained by an improved particle swarm optimisation (IPSO) algorithm. The proposed IPSO technique can improve convergence performance of the primary PSO through the following strategies: nonlinear processing of inertia weight, introductions of the black hole and simulated annealing model with extremum disturbance. The good generalisation ability of the IPSO-SVM model has been validated through adding additional specimen into the testing set. Experiments show that the proposed algorithm can achieve higher recognition accuracy and efficiency than other well-known classifiers and the superiorities are more obvious with less training set, which contributes to online application.

  14. Reliability of Current Biokinetic and Dosimetric Models for Radionuclides: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL; Meck, Robert A. [U.S. Nuclear Regulatory Commission

    2008-10-01

    This report describes the results of a pilot study of the reliability of the biokinetic and dosimetric models currently used by the U.S. Nuclear Regulatory Commission (NRC) as predictors of dose per unit internal or external exposure to radionuclides. The study examines the feasibility of critically evaluating the accuracy of these models for a comprehensive set of radionuclides of concern to the NRC. Each critical evaluation would include: identification of discrepancies between the models and current databases; characterization of uncertainties in model predictions of dose per unit intake or unit external exposure; characterization of variability in dose per unit intake or unit external exposure; and evaluation of prospects for development of more accurate models. Uncertainty refers here to the level of knowledge of a central value for a population, and variability refers to quantitative differences between different members of a population. This pilot study provides a critical assessment of models for selected radionuclides representing different levels of knowledge of dose per unit exposure. The main conclusions of this study are as follows: (1) To optimize the use of available NRC resources, the full study should focus on radionuclides most frequently encountered in the workplace or environment. A list of 50 radionuclides is proposed. (2) The reliability of a dose coefficient for inhalation or ingestion of a radionuclide (i.e., an estimate of dose per unit intake) may depend strongly on the specific application. Multiple characterizations of the uncertainty in a dose coefficient for inhalation or ingestion of a radionuclide may be needed for different forms of the radionuclide and different levels of information of that form available to the dose analyst. (3) A meaningful characterization of variability in dose per unit intake of a radionuclide requires detailed information on the biokinetics of the radionuclide and hence is not feasible for many infrequently

  15. Modelling Monsoons: Understanding and Predicting Current and Future Behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A; Sperber, K R; Slingo, J M; Meehl, G A; Mechoso, C R; Kimoto, M; Giannini, A

    2008-09-16

    including, but not limited to, the Mei-Yu/Baiu sudden onset and withdrawal, low-level jet orientation and variability, and orographic forced rainfall. Under anthropogenic climate change many competing factors complicate making robust projections of monsoon changes. Without aerosol effects, increased land-sea temperature contrast suggests strengthened monsoon circulation due to climate change. However, increased aerosol emissions will reflect more solar radiation back to space, which may temper or even reduce the strength of monsoon circulations compared to the present day. A more comprehensive assessment is needed of the impact of black carbon aerosols, which may modulate that of other anthropogenic greenhouse gases. Precipitation may behave independently from the circulation under warming conditions in which an increased atmospheric moisture loading, based purely on thermodynamic considerations, could result in increased monsoon rainfall under climate change. The challenge to improve model parameterizations and include more complex processes and feedbacks pushes computing resources to their limit, thus requiring continuous upgrades of computational infrastructure to ensure progress in understanding and predicting the current and future behavior of monsoons.

  16. Modelling of radial electric fields and currents during divertor plate biasing on TdeV

    International Nuclear Information System (INIS)

    Lachambre, J.L.; Quirion, B.; Boucher, C.

    1994-01-01

    A simple model based on non-ambipolar radial transport and planar sheath physics is used to describe the generation of radial electric fields and currents in the scrape-off layer of the Tokamak de Varennes (TdeV) during divertor plate biasing. In general, the calculated predictions compare favourably with TdeV results over a variety of plasma conditions and divertor magnetic configurations. Validated by the experiment, the model is used to study the scaling laws of perpendicular ion mobility and to test existing related theories. Finally, the model is proposed as a useful tool for the design and upgrade of biased divertors through optimization of the plate and throat geometry. (author). 35 refs, 16 figs, 1 tab

  17. Automating Construction of Machine Learning Models With Clinical Big Data: Proposal Rationale and Methods.

    Science.gov (United States)

    Luo, Gang; Stone, Bryan L; Johnson, Michael D; Tarczy-Hornoch, Peter; Wilcox, Adam B; Mooney, Sean D; Sheng, Xiaoming; Haug, Peter J; Nkoy, Flory L

    2017-08-29

    To improve health outcomes and cut health care costs, we often need to conduct prediction/classification using large clinical datasets (aka, clinical big data), for example, to identify high-risk patients for preventive interventions. Machine learning has been proposed as a key technology for doing this. Machine learning has won most data science competitions and could support many clinical activities, yet only 15% of hospitals use it for even limited purposes. Despite familiarity with data, health care researchers often lack machine learning expertise to directly use clinical big data, creating a hurdle in realizing value from their data. Health care researchers can work with data scientists with deep machine learning knowledge, but it takes time and effort for both parties to communicate effectively. Facing a shortage in the United States of data scientists and hiring competition from companies with deep pockets, health care systems have difficulty recruiting data scientists. Building and generalizing a machine learning model often requires hundreds to thousands of manual iterations by data scientists to select the following: (1) hyper-parameter values and complex algorithms that greatly affect model accuracy and (2) operators and periods for temporally aggregating clinical attributes (eg, whether a patient's weight kept rising in the past year). This process becomes infeasible with limited budgets. This study's goal is to enable health care researchers to directly use clinical big data, make machine learning feasible with limited budgets and data scientist resources, and realize value from data. This study will allow us to achieve the following: (1) finish developing the new software, Automated Machine Learning (Auto-ML), to automate model selection for machine learning with clinical big data and validate Auto-ML on seven benchmark modeling problems of clinical importance; (2) apply Auto-ML and novel methodology to two new modeling problems crucial for care

  18. Analytical model for the TeraHertz current noise in nanometric Schottky-barrier diodes and heterostructure barrier varactors

    Energy Technology Data Exchange (ETDEWEB)

    Mahi, F Z; Helmaoui, A [Physics of Semiconductor Devices Laboratory (LPDS), University of Bechar (Algeria); Varani, L [Institute of Electronics of the South (IES - CNRS UMR 5214), University of Montpellier (France); Shiktorov, P; Starikov, E; Gruzhinskis, V, E-mail: fati_zo_mahi2002@yahoo.f [Semiconductor Physics Institute, Vilnius (Lithuania)

    2009-11-15

    In this paper we propose an analytical model for the calculation of the spectral density of current fluctuations in Heterostructure-barrier varactors . The structures of the calculated spectra are analyzed in terms of physical processes useful to optimize the device parameters for the extraction of the high-order harmonics.

  19. Chaos control in an electron beam with the supercritical current in the hydrodynamic model of the Pierce diode

    International Nuclear Information System (INIS)

    Koronovskij, A.A.; Rempen, I.S.; Khramov, A.E.

    2003-01-01

    The possibility of controlling the chaos in the electron beam with the supercritical current in the hydrodynamic model of the Pierce diode through the continuous feedback; the methodology of controlling the chaotic dynamics through stabilization of the unstable equilibrium state in the distributed active medium is proposed [ru

  20. Angular approach combined to mechanical model for tool breakage detection by eddy current sensors

    Science.gov (United States)

    Ritou, M.; Garnier, S.; Furet, B.; Hascoet, J. Y.

    2014-02-01

    The paper presents a new complete approach for Tool Condition Monitoring (TCM) in milling. The aim is the early detection of small damages so that catastrophic tool failures are prevented. A versatile in-process monitoring system is introduced for reliability concerns. The tool condition is determined by estimates of the radial eccentricity of the teeth. An adequate criterion is proposed combining mechanical model of milling and angular approach.Then, a new solution is proposed for the estimate of cutting force using eddy current sensors implemented close to spindle nose. Signals are analysed in the angular domain, notably by synchronous averaging technique. Phase shifts induced by changes of machining direction are compensated. Results are compared with cutting forces measured with a dynamometer table.The proposed method is implemented in an industrial case of pocket machining operation. One of the cutting edges has been slightly damaged during the machining, as shown by a direct measurement of the tool. A control chart is established with the estimates of cutter eccentricity obtained during the machining from the eddy current sensors signals. Efficiency and reliability of the method is demonstrated by a successful detection of the damage.

  1. Can Mindfulness Training Improve Medication Adherence? Integrative Review of the Current Evidence and Proposed Conceptual Model.

    Science.gov (United States)

    Salmoirago-Blotcher, Elena; Carey, Michael P

    Medication adherence is a complex, multi-determined behavior that is often influenced by system- (e.g., cost), drug- (e.g., regimen complexity), and patient-related (e.g., depression) factors. System-level approaches (e.g., making medications more affordable) are critically important but do not address patient-level factors that can undermine adherence. In this paper, we identify patient-level determinants of non-adherence and discuss whether mindfulness-training approaches that target these determinants can help to improve adherence to medical treatment. We highlight two chronic medical conditions (viz., heart failure and HIV) where poor adherence is a significant concern, and examine the evidence regarding the use of mindfulness interventions to improve medication adherence in these two conditions. We also discuss the theoretical underpinnings of mindfulness training with respect to medication adherence, and conclude by suggesting directions for future research. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Numerical modeling of lower hybrid heating and current drive

    International Nuclear Information System (INIS)

    Valeo, E.J.; Eder, D.C.

    1986-03-01

    The generation of currents in toroidal plasma by application of waves in the lower hybrid frequency range involves the interplay of several physical phenomena which include: wave propagation in toroidal geometry, absorption via wave-particle resonances, the quasilinear generation of strongly nonequilibrium electron and ion distribution functions, and the self-consistent evolution of the current density in such a nonequilibrium plasma. We describe a code, LHMOD, which we have developed to treat these aspects of current drive and heating in tokamaks. We present results obtained by applying the code to a computation of current ramp-up and to an investigation of the possible importance of minority hydrogen absorption in a deuterium plasma as the ''density limit'' to current drive is approached

  3. 78 FR 38091 - Airworthiness Criteria: Proposed Airship Design Criteria for Lockheed Martin Aeronautics Model...

    Science.gov (United States)

    2013-06-25

    ..., 2012 Lockheed Martin Aeronautics submitted an application for type certification for the model LMZ1M..., views, or arguments as they may desire. Commenters should identify the proposed design criteria on the... Lockheed Martin Aeronautics submitted an application for type certification for the model LMZ1M airship...

  4. Proposed Model of Information Behaviour in Crisis: The Case of Hurricane Sandy

    Science.gov (United States)

    Lopatovska, Irene; Smiley, Bobby

    2013-01-01

    Introduction: The paper proposes a model of information behaviour in crisis. No previous model has attempted to integrate information resources, information behaviour and needs of the storm-affected communities within the temporal stages of a natural disaster. Method: The study was designed as autoethnography. The data were collected through a…

  5. Non-monotonic reasoning in conceptual modeling and ontology design: A proposal

    CSIR Research Space (South Africa)

    Casini, G

    2013-06-01

    Full Text Available -1 2nd International Workshop on Ontologies and Conceptual Modeling (Onto.Com 2013), Valencia, Spain, 17-21 June 2013 Non-monotonic reasoning in conceptual modeling and ontology design: A proposal Giovanni Casini1 and Alessandro Mosca2 1...

  6. The Proposed Model of Collaborative Virtual Learning Environment for Introductory Programming Course

    Science.gov (United States)

    Othman, Mahfudzah; Othman, Muhaini

    2012-01-01

    This paper discusses the proposed model of the collaborative virtual learning system for the introductory computer programming course which uses one of the collaborative learning techniques known as the "Think-Pair-Share". The main objective of this study is to design a model for an online learning system that facilitates the…

  7. Individualized model predicts brain current flow during transcranial direct-current stimulation treatment in responsive stroke patient.

    Science.gov (United States)

    Datta, Abhishek; Baker, Julie M; Bikson, Marom; Fridriksson, Julius

    2011-07-01

    Although numerous published reports have demonstrated the beneficial effects of transcranial direct-current stimulation (tDCS) on task performance, fundamental questions remain regarding the optimal electrode configuration on the scalp. Moreover, it is expected that lesioned brain tissue will influence current flow and should therefore be considered (and perhaps leveraged) in the design of individualized tDCS therapies for stroke. The current report demonstrates how different electrode configurations influence the flow of electrical current through brain tissue in a patient who responded positively to a tDCS treatment targeting aphasia. The patient, a 60-year-old man, sustained a left hemisphere ischemic stroke (lesion size = 87.42 mL) 64 months before his participation. In this study, we present results from the first high-resolution (1 mm(3)) model of tDCS in a brain with considerable stroke-related damage; the model was individualized for the patient who received anodal tDCS to his left frontal cortex with the reference cathode electrode placed on his right shoulder. We modeled the resulting brain current flow and also considered three additional reference electrode positions: right mastoid, right orbitofrontal cortex, and a "mirror" configuration with the anode over the undamaged right cortex. Our results demonstrate the profound effect of lesioned tissue on resulting current flow and the ability to modulate current pattern through the brain, including perilesional regions, through electrode montage design. The complexity of brain current flow modulation by detailed normal and pathologic anatomy suggest: (1) That computational models are critical for the rational interpretation and design of individualized tDCS stroke-therapy; and (2) These models must accurately reproduce head anatomy as shown here. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Proposal of leak path passivation for InGaN solar cells to reduce the leakage current

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke, E-mail: ke.wang@chiba-u.jp; Imai, Daichi; Kusakabe, Kazuhide [Center for SMART Green Innovation Research, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Yoshikawa, Akihiko, E-mail: yoshi@faculty.chiba-u.jp [Center for SMART Green Innovation Research, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Department of Information and Communication Engineering, Graduate School of Engineering, Kogakuin University, Nakano-cho, Hachioji, Tokyo 2665-1 (Japan)

    2016-01-25

    We propose some general ways to passivate the leak paths in InGaN solar cells and report some experimental evidences of its effectiveness. By adopting an AlOx passivation process, the photovoltaic performances of GaN pn-junctions and InGaN solar cells, grown by molecular beam epitaxy, have been significantly improved. The open circuit voltage under 1 sun illumination increases from 1.46 to 2.26 V for a GaN pn junction, and from 0.95 to 1.27 V for an InGaN solar cell, demonstrating evidence of leak path passivation (LPP) by AlOx. The proposed LPP is expected to be a realistic way to exploit the potential of thick and relaxed but defective InGaN for solar cell applications.

  9. Transformer core modeling for magnetizing inrush current investigation

    Directory of Open Access Journals (Sweden)

    A.Yahiou

    2014-03-01

    Full Text Available The inrush currents generated during an energization of power transformer can reach very high values and may cause many problems in power system. This magnetizing inrush current which occurs at the time of energization of a transformer is due to temporary overfluxing in the transformer core. Its magnitude mainly depends on switching parameters such as the resistance of the primary winding and the point-on-voltage wave (switching angle. This paper describes a system for measuring the inrush current which is composed principally of an acquisition card (EAGLE, and LabVIEW code. The system is also capable of presetting various combinations of switching parameters for the energization of a 2 kVA transformer via an electronic card. Moreover, an algorithm for calculating the saturation curve is presented taking the iron core reactive losses into account, thereby producing a nonlinear inductance. This curve is used to simulate the magnetizing inrush current using the ATP-EMTP software.

  10. CCIEA data and model output - California Current Integrated Ecosystem Assessment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The California Current Integrated Ecosystem Assessment (CCIEA) is a joint project between staff at the NWFSC, SWFSC, NMML, ONMS, and WCRO to provide managers and...

  11. Modelling and Optimization of Four-Segment Shielding Coils of Current Transformers.

    Science.gov (United States)

    Gao, Yucheng; Zhao, Wei; Wang, Qing; Qu, Kaifeng; Li, He; Shao, Haiming; Huang, Songling

    2017-05-26

    Applying shielding coils is a practical way to protect current transformers (CTs) for large-capacity generators from the intensive magnetic interference produced by adjacent bus-bars. The aim of this study is to build a simple analytical model for the shielding coils, from which the optimization of the shielding coils can be calculated effectively. Based on an existing stray flux model, a new analytical model for the leakage flux of partial coils is presented, and finite element method-based simulations are carried out to develop empirical equations for the core-pickup factors of the models. Using the flux models, a model of the common four-segment shielding coils is derived. Furthermore, a theoretical analysis is carried out on the optimal performance of the four-segment shielding coils in a typical six-bus-bars scenario. It turns out that the "all parallel" shielding coils with a 45° starting position have the best shielding performance, whereas the "separated loop" shielding coils with a 0° starting position feature the lowest heating value. Physical experiments were performed, which verified all the models and the conclusions proposed in the paper. In addition, for shielding coils with other than the four-segment configuration, the analysis process will generally be the same.

  12. BLAM (Benthic Light Availability Model): A Proposed Model of Hydrogeomorphic Controls on Light in Rivers

    Science.gov (United States)

    Julian, J. P.; Doyle, M. W.; Stanley, E. H.

    2006-12-01

    Light is vital to the dynamics of aquatic ecosystems. It drives photosynthesis and photochemical reactions, affects thermal structure, and influences behavior of aquatic biota. Despite the fundamental role of light to riverine ecosystems, light studies in rivers have been mostly neglected because i) boundary conditions (e.g., banks, riparian vegetation) make ambient light measurements difficult, and ii) the optical water quality of rivers is highly variable and difficult to characterize. We propose a benthic light availability model (BLAM) that predicts the percent of incoming photosynthetically active radiation (PAR) available at the river bed. BLAM was developed by quantifying light attenuation of the five hydrogeomorphic controls that dictate riverine light availability: topography, riparian vegetation, channel geometry, optical water quality, and water depth. BLAM was calibrated using hydrogeomorphic data and light measurements from two rivers: Deep River - a 5th-order, turbid river in central North Carolina, and Big Spring Creek - a 2nd-order, optically clear stream in central Wisconsin. We used a series of four PAR sensors to measure i) above-canopy PAR, ii) PAR above water surface, iii) PAR below water surface, and iv) PAR on stream bed. These measurements were used to develop empirical light attenuation coefficients, which were then used in combination with optical water quality measurements, shading analyses, channel surveys, and flow records to quantify the spatial and temporal variability in riverine light availability. Finally, we apply BLAM to the Baraboo River - a 6th-order, 120-mile, unimpounded river in central Wisconsin - in order to characterize light availability along the river continuum (from headwaters to mouth).

  13. A System Thinking Model Proposal for Enterprise Application Integration (EAI Evaluation Completeness

    Directory of Open Access Journals (Sweden)

    Irene Nakiyimba

    2014-01-01

    Full Text Available Research has identified a number of approaches for evaluating Enterprise Application Integration (EAI. The majority of these approaches focus primarily on the technical functional and non-functional capabil¬ities of an EAI solution. Although, where the technical dimensions have received considerable attention from researchers, other dimensions needed for EAI evaluation, such as stakeholder feedback, have not re¬ceived explicit consideration. As a result, attaining a consummate EAI solution is still a major challenge for many enterprises. The current EAI evaluation models simply provide piecemeal insights towards the evaluation criteria variables from limited stakeholder perceptions and do not help to understand EAI evaluation as a dynamic, feedback, time based and non-linear problem. Different stakeholders view the outcome of an EAI project from different perspectives and therefore will more likely than not arrive at different conclusions. To achieve a consensus among stakeholder perceptions, we represent EAI evaluation as a feedback analysis problem from multi-stakeholder perceptions for proper alignment with business goals, vision and mission. This paper proposes the application of System Dynamics (SD model towards guiding policy analysis for evaluating criteria factors from multi-stakeholders perceptions for EAI adoption; this will provide for holistic evaluation where emphasis is the importance of evaluation as whole (not piece meal perceptions and the interdependence of evaluation criteria factors from the diverse stakeholder perceptions is analyzed. In this paper we present a case-study performed at a large portion of the East African banking system. A total of 800 responses to questionnaires are analyzed to formulate a systems thinking model, which in turn allows us to analyze feedback loops between different stakeholders with distinct evaluation criteria. Findings result in a structured and holistic systems thinking model which

  14. Light extraction in planar light-emitting diode with nonuniform current injection: model and simulation.

    Science.gov (United States)

    Khmyrova, Irina; Watanabe, Norikazu; Kholopova, Julia; Kovalchuk, Anatoly; Shapoval, Sergei

    2014-07-20

    We develop an analytical and numerical model for performing simulation of light extraction through the planar output interface of the light-emitting diodes (LEDs) with nonuniform current injection. Spatial nonuniformity of injected current is a peculiar feature of the LEDs in which top metal electrode is patterned as a mesh in order to enhance the output power of light extracted through the top surface. Basic features of the model are the bi-plane computation domain, related to other areas of numerical grid (NG) cells in these two planes, representation of light-generating layer by an ensemble of point light sources, numerical "collection" of light photons from the area limited by acceptance circle and adjustment of NG-cell areas in the computation procedure by the angle-tuned aperture function. The developed model and procedure are used to simulate spatial distributions of the output optical power as well as the total output power at different mesh pitches. The proposed model and simulation strategy can be very efficient in evaluation of the output optical performance of LEDs with periodical or symmetrical configuration of the electrodes.

  15. Comparing Symptoms of Autism Spectrum Disorders Using the Current "DSM-IV-TR" Diagnostic Criteria and the Proposed "DSM-V" Diagnostic Criteria

    Science.gov (United States)

    Worley, Julie A.; Matson, Johnny L.

    2012-01-01

    The American Psychiatric Association has proposed major revisions for the diagnostic category encompassing Autism Spectrum Disorders (ASD), which will reportedly increase the specificity and maintain the sensitivity of diagnoses. As a result, the aim of the current study was to compare symptoms of ASD in children and adolescents (N = 208) who met…

  16. Analytical Modeling Of The Steinmetz Coefficient For Single-Phase Transformer Eddy Current Loss Prediction

    Directory of Open Access Journals (Sweden)

    T. Aly Saandy

    2015-08-01

    Full Text Available Abstract This article presents to an analytical calculation methodology of the Steinmetz coefficient applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active power consumed by the core is expressed analytically in function of the electrical parameters as resistivity and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The required coefficient is identified from the empirical Steinmetz data based on the experimented active power expression. To verify the relevance of the model validations both by simulations with two in two different frequencies and measurements were carried out. The obtained results are in good agreement with the theoretical approach and the practical results.

  17. Data Center IT Equipment Energy Assessment Tools: Current State of Commercial Tools, Proposal for a Future Set of Assessment Tools

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, Ben D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); National Univ., San Diego, CA (United States). School of Engineering

    2012-06-30

    This research project, which was conducted during the Summer and Fall of 2011, investigated some commercially available assessment tools with a focus on IT equipment to see if such tools could round out the DC Pro tool suite. In this research, the assessment capabilities of the various tools were compiled to help make “non-biased” information available to the public. This research should not be considered to be exhaustive on all existing vendor tools although a number of vendors were contacted. Large IT equipment OEM’s like IBM and Dell provide their proprietary internal automated software which does not work on any other IT equipment. However, found two companies with products that showed promise in performing automated assessments for IT equipment from different OEM vendors. This report documents the research and provides a list of software products reviewed, contacts and websites, product details, discussions with specific companies, a set of recommendations, and next steps. As a result of this research, a simple 3-level approach to an IT assessment tool is proposed along with an example of an assessment using a simple IT equipment data collection tool (Level 1, spreadsheet). The tool has been reviewed with the Green Grid and LBNL staff. The initial feedback has been positive although further refinement to the tool will be necessary. Proposed next steps include a field trial of at least two vendors’ software in two different data centers with an objective to prove the concept, ascertain the extent of energy and computational assessment, ease of installation and opportunities for continuous improvement. Based on the discussions, field trials (or case studies) are proposed with two vendors – JouleX (expected to be completed in 2012) and Sentilla.

  18. Two-Dimensional Model Test Study of New Western Breakwater Proposal for Port of Hanstholm

    DEFF Research Database (Denmark)

    Eldrup, Mads Røge; Andersen, Thomas Lykke

    The present report presents results from a two-dimensional model test study carried out at Aalborg University in December 2016 with the proposed trunk section for the new western breakwater in Port of Hanstholm. The objectives of the model tests were to study the stability of the armour layer, toe...... erosion, overtopping and transmission. The scale used for the model tests was 1:61.5. Unless otherwise specified all values given in this report are prototype values converted from the model to prototype according to the Froude model law....

  19. An analysis of pharmaceutical experience with decades of rat carcinogenicity testing: support for a proposal to modify current regulatory guidelines.

    Science.gov (United States)

    Sistare, Frank D; Morton, Daniel; Alden, Carl; Christensen, Joel; Keller, Douglas; Jonghe, Sandra De; Storer, Richard D; Reddy, M Vijayaraj; Kraynak, Andrew; Trela, Bruce; Bienvenu, Jean-Guy; Bjurström, Sivert; Bosmans, Vanessa; Brewster, David; Colman, Karyn; Dominick, Mark; Evans, John; Hailey, James R; Kinter, Lewis; Liu, Matt; Mahrt, Charles; Marien, Dirk; Myer, James; Perry, Richard; Potenta, Daniel; Roth, Arthur; Sherratt, Philip; Singer, Thomas; Slim, Rabih; Soper, Keith; Fransson-Steen, Ronny; Stoltz, James; Turner, Oliver; Turnquist, Susan; van Heerden, Marjolein; Woicke, Jochen; DeGeorge, Joseph J

    2011-06-01

    Data collected from 182 marketed and nonmarketed pharmaceuticals demonstrate that there is little value gained in conducting a rat two-year carcinogenicity study for compounds that lack: (1) histopathologic risk factors for rat neoplasia in chronic toxicology studies, (2) evidence of hormonal perturbation, and (3) positive genetic toxicology results. Using a single positive result among these three criteria as a test for outcome in the two-year study, fifty-two of sixty-six rat tumorigens were correctly identified, yielding 79% test sensitivity. When all three criteria were negative, sixty-two of seventy-six pharmaceuticals (82%) were correctly predicted to be rat noncarcinogens. The fourteen rat false negatives had two-year study findings of questionable human relevance. Applying these criteria to eighty-six additional chemicals identified by the International Agency for Research on Cancer as likely human carcinogens and to drugs withdrawn from the market for carcinogenicity concerns confirmed their sensitivity for predicting rat carcinogenicity outcome. These analyses support a proposal to refine regulatory criteria for conducting a two-year rat study to be based on assessment of histopathologic findings from a rat six-month study, evidence of hormonal perturbation, genetic toxicology results, and the findings of a six-month transgenic mouse carcinogenicity study. This proposed decision paradigm has the potential to eliminate over 40% of rat two-year testing on new pharmaceuticals without compromise to patient safety.

  20. Analysis of Ion Currents Contribution to Repolarization in Human Heart Failure Using Computer Models

    Energy Technology Data Exchange (ETDEWEB)

    Marotta, F.; Paci, M.A.; Severi, S.; Trenor, B.

    2016-07-01

    The mechanisms underlying repolarization of the ventricular action potential (AP) are subject of research for anti-arrhythmic drugs. In fact, the prolongation of the AP occurs in several conditions of heart disease, such as heart failure, a major problem precursor for serious arrhythmias. In this study, we investigated the phenomena of repolarization reserve, defined as the capacity of the cell to repolarize in case of a functional loss, and the all-or-none repolarization, which depends on the delicate balance of inward and outward currents in the different phases of the AP, under conditions of human heart failure (HF). To simulate HF conditions, the O'Hara et al. human AP model was modified and specific protocols for all-or-none repolarization were applied. Our results show that in the early repolarization the threshold for all-or-none repolarization is not altered in HF even if a decrease in potassium currents can be observed. To quantify the contribution of the individual ion currents to HF induced AP prolongation, we used a novel piecewise-linear approximation approach proposed by Paci et al. In particular, INaL and ICaL are the main responsible for APD prolongation due to HF (85 and 35 ms respectively). Our results highlight this novel algorithm as a powerful tool to have a more complete picture of the complex ionic mechanisms underlying this disease and confirm the important role of the late sodium current in HF repolarization. (Author)

  1. Hybrid Models of Alternative Current Filter for Hvdc

    Directory of Open Access Journals (Sweden)

    Ufa Ruslan A.

    2017-01-01

    Full Text Available Based on a hybrid simulation concept of HVDC, the developed hybrid AC filter models, providing the sufficiently full and adequate modeling of all single continuous spectrum of quasi-steady-state and transient processes in the filter, are presented. The obtained results suggest that usage of the hybrid simulation approach is carried out a methodically accurate with guaranteed instrumental error solution of differential equation systems of mathematical models of HVDC.

  2. The Motivational Knowledge Management Model: proposal to apply it in the library sector

    Directory of Open Access Journals (Sweden)

    Daniel López-Fernández

    2016-12-01

    Full Text Available In professional environments, attention paid to aspects such as supervisory styles, interpersonal relationships and workers eagerness can have a positive impact on employee motivation and, consequently, on their performance and well-being. To achieve this, knowledge management models such as those presented here can be applied. This model generates diagnoses of motivation and recommendations for improvement, both systematically and scientifically. Consequently, it is especially useful for managers and human resource departments. The proposed model can be adapted to different kinds of professional groups, including those in library and documentation services. The suitability, reliability and usefulness of the proposed model have been empirically checked through case studies with 92 students and 166 professionals. The positive results allow us to conclude that the model is effective and useful for assessing and improving motivation.

  3. The ERICAM model: a proposal for amelioration of nuclear liability by funding on the capital markets

    International Nuclear Information System (INIS)

    Tyran, J.R.

    1995-01-01

    The ERICAM model (Environmental Risk Internalization through Capital Markets) includes the capital markets as a source contributing to the coverage of risks due to nuclear activites, thus enhancing the effectiveness and functions of the nuclear liability law. The model proposed will allow higher amounts for compensation and will increase financial security, flow of information, and efficient use of resources. The implementation of the model can be achieved on the financing side by issuing Nuke bonds, linking accident-specific options to government bonds. This will essentially increase the risk coverage compared to present means, and will be a pin-pointed addition to the existing layer system. There are three institutions proposed to act as mediators in the implementation of the model: A government authority to supervise the trade in Nuke bonds. Risk-bearing associations in oder to enhance the model's efficiency, and to reduce transaction costs. Rating agencies that will reduce the expenditure for information. (orig./HP) [de

  4. Proposal for a Method for Business Model Performance Assessment: Toward an Experimentation Tool for Business Model Innovation

    Directory of Open Access Journals (Sweden)

    Antonio Batocchio

    2017-04-01

    Full Text Available The representation of business models has been recently widespread, especially in the pursuit of innovation. However, defining a company’s business model is sometimes limited to discussion and debates. This study observes the need for performance measurement so that business models can be data-driven. To meet this goal, the work proposed as a hypothesis the creation of a method that combines the practices of the Balanced Scorecard with a method of business models representation – the Business Model Canvas. Such a combination was based on study of conceptual adaptation, resulting in an application roadmap. A case study application was performed to check the functionality of the proposition, focusing on startup organizations. It was concluded that based on the performance assessment of the business model it is possible to propose the search for change through experimentation, a path that can lead to business model innovation.

  5. A self-report measure for the ICD-11 dimensional trait model proposal: The personality inventory for ICD-11.

    Science.gov (United States)

    Oltmanns, Joshua R; Widiger, Thomas A

    2018-02-01

    Proposed for the 11th edition of the World Health Organization's International Classification of Diseases (ICD-11) is a dimensional trait model for the classification of personality disorder (Tyrer, Reed, & Crawford, 2015). The ICD-11 proposal consists of 5 broad domains: negative affective, detachment, dissocial, disinhibition, and anankastic (Mulder, Horwood, Tyrer, Carter, & Joyce, 2016). Several field trials have examined this proposal, yet none has included a direct measure of the trait model. The purpose of the current study was to develop and provide initial validation for the Personality Inventory for ICD-11 (PiCD), a self-report measure of this proposed 5-domain maladaptive trait model. Item selection and scale construction proceeded through 3 initial data collections assessing potential item performance. Two subsequent studies were conducted for scale validation. In Study 1, the PiCD was evaluated in a sample of 259 MTurk participants (who were or had been receiving mental health treatment) with respect to 2 measures of general personality structure: The Eysenck Personality Questionnaire-Revised and the 5-Dimensional Personality Test. In Study 2, the PiCD was evaluated in an additional sample of 285 participants with respect to 2 measures of maladaptive personality traits: The Personality Inventory for DSM-5 and the Computerized Adaptive Test for Personality Disorders. Study 3 provides an item-level exploratory structural equation model with the combined samples from Studies 1 and 2. The results are discussed with respect to the validity of the measure and the potential benefits for future research in having a direct, self-report measure of the ICD-11 trait proposal. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  6. Modelling current transfer to cathodes in metal halide plasmas

    International Nuclear Information System (INIS)

    Benilov, M S; Cunha, M D; Naidis, G V

    2005-01-01

    This work is concerned with investigation of the main features of current transfer to cathodes under conditions characteristic of metal halide (MH) lamps. It is found that the presence of MHs in the gas phase results in a small decrease of the cathode surface temperature and of the near-cathode voltage drop in the diffuse mode of current transfer; the range of stability of the diffuse mode expands. Effects caused by a variation of the work function of the cathode surface owing to formation of a monolayer of alkali metal atoms on the surface are studied for particular cases where the monolayer is composed of sodium or caesium. It is found that the formation of the sodium monolayer affects the diffuse mode of current transfer only moderately and in the same direction that the presence of metal atoms in the gas phase affects it. Formation of the caesium monolayer produces a dramatic effect: the cathode surface temperature decreases very strongly, the diffuse-mode current-voltage characteristic becomes N-S-shaped

  7. Integral Model of Eddy Currents in Nonmagnetic Structures

    Czech Academy of Sciences Publication Activity Database

    Doležel, Ivo; Karban, P.

    2004-01-01

    Roč. 4, č. 3 (2004), s. 5-12 ISSN 1335-8243 R&D Projects: GA ČR GA102/03/0047 Keywords : magnetic field * eddy currents * integral equations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  8. A Summary of Proposed Changes to the Current ICARTT Format Standards and their Implications to Future Airborne Studies

    Science.gov (United States)

    Northup, Emily; Benson Early, Amanda; Beach, Aubrey; Wang, Dali; Kusterer, John; Quam, Brandi; Chen, Gao

    2015-01-01

    The Atmospheric Science Data Center (ASDC) at NASA Langley Research Center is responsible for the ingest, archive, and distribution of NASA Earth Science data in the areas of radiation budget, clouds, aerosols, and tropospheric chemistry. The ASDC specializes in atmospheric data that is important to understanding the causes and processes of global climate change and the consequences of human activities on the climate. The ASDC currently supports more than 44 projects and has over 1,700 archived data sets, which increase daily. ASDC customers include scientists, researchers, federal, state, and local governments, academia, industry, and application users, the remote sensing community, and the general public.

  9. Environmental services in Zavidovici (Bosnia Herzegovina): current situation and proposals for intervention-Part 1.: Drinking water treatment and distribution

    International Nuclear Information System (INIS)

    Vaccari, M.; Collivignarelli, C.; Vitali, F.

    2009-01-01

    The state of the environment in Bosnia Herzegovina, already compromised before the war by the development of heavy industry, worsened after the conflict. The country is facing difficult issues in the supply of environmental services, which have recently been overlooked with regard to full coverage of the territory with adequate infrastructures and appropriate management of the existing ones. Several years ago CeTAmb started collaborating with the Local Democracy Agency in Zavidovici and local institutions: within that cooperation a survey of environmental services (water supply, wastewater collection and treatment, solid waste management) supplied to the municipal territory was implemented. The first part of the paper presents the different issues, and relative improvement solutions proposed, resulting from an analysis of the water supply infrastructures, with regard to both quantity and quality. [it

  10. Analytical modeling and analysis of magnetic field and torque for novel axial flux eddy current couplers with PM excitation

    Science.gov (United States)

    Li, Zhao; Wang, Dazhi; Zheng, Di; Yu, Linxin

    2017-10-01

    Rotational permanent magnet eddy current couplers are promising devices for torque and speed transmission without any mechanical contact. In this study, flux-concentration disk-type permanent magnet eddy current couplers with double conductor rotor are investigated. Given the drawback of the accurate three-dimensional finite element method, this paper proposes a mixed two-dimensional analytical modeling approach. Based on this approach, the closed-form expressions of magnetic field, eddy current, electromagnetic force and torque for such devices are obtained. Finally, a three-dimensional finite element method is employed to validate the analytical results. Besides, a prototype is manufactured and tested for the torque-speed characteristic.

  11. A proposed strategy for the validation of ground-water flow and solute transport models

    International Nuclear Information System (INIS)

    Davis, P.A.; Goodrich, M.T.

    1991-01-01

    Ground-water flow and transport models can be thought of as a combination of conceptual and mathematical models and the data that characterize a given system. The judgment of the validity or invalidity of a model depends both on the adequacy of the data and the model structure (i.e., the conceptual and mathematical model). This report proposes a validation strategy for testing both components independently. The strategy is based on the philosophy that a model cannot be proven valid, only invalid or not invalid. In addition, the authors believe that a model should not be judged in absence of its intended purpose. Hence, a flow and transport model may be invalid for one purpose but not invalid for another. 9 refs

  12. Survey of current situation in radiation belt modeling

    Science.gov (United States)

    Fung, Shing F.

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

  13. Modeling of air currents in the Gulf Region

    International Nuclear Information System (INIS)

    Sullivan, T.J.; Ellis, J.S.; Foster, C.S.; Foster, K.T.; Baskett, R.L.; Nasstrom, J.S.; Schalk, W.W.

    1992-01-01

    The Atmospheric Release Advisory Capability modeled the wind flow in the Gulf Region in order to make projections of the Kuwait oil fires pollution dispersion. Extensive meteorological models incorporating explicit terrain influences to the flow fields were routinely employed through a six month international assessment support effort organized by the World Meteorological Organization and US scientific research agencies. Results show generally close agreement with visible imagery of the smoke plumes as detected by meteorological satellites. However, there are some examples of significant disagreement or failure of the meteorological models. These failures are most likely directly linked to missing or unavailable weather observations

  14. Integrated modeling of plasma ramp-up in DIII-D ITER-like and high bootstrap current scenario discharges

    Science.gov (United States)

    Wu, M. Q.; Pan, C. K.; Chan, V. S.; Li, G. Q.; Garofalo, A. M.; Jian, X.; Liu, L.; Ren, Q. L.; Chen, J. L.; Gao, X.; Gong, X. Z.; Ding, S. Y.; Qian, J. P.; Cfetr Physics Team

    2018-04-01

    Time-dependent integrated modeling of DIII-D ITER-like and high bootstrap current plasma ramp-up discharges has been performed with the equilibrium code EFIT, and the transport codes TGYRO and ONETWO. Electron and ion temperature profiles are simulated by TGYRO with the TGLF (SAT0 or VX model) turbulent and NEO neoclassical transport models. The VX model is a new empirical extension of the TGLF turbulent model [Jian et al., Nucl. Fusion 58, 016011 (2018)], which captures the physics of multi-scale interaction between low-k and high-k turbulence from nonlinear gyro-kinetic simulation. This model is demonstrated to accurately model low Ip discharges from the EAST tokamak. Time evolution of the plasma current density profile is simulated by ONETWO with the experimental current ramp-up rate. The general trend of the predicted evolution of the current density profile is consistent with that obtained from the equilibrium reconstruction with Motional Stark effect constraints. The predicted evolution of βN , li , and βP also agrees well with the experiments. For the ITER-like cases, the predicted electron and ion temperature profiles using TGLF_Sat0 agree closely with the experimental measured profiles, and are demonstrably better than other proposed transport models. For the high bootstrap current case, the predicted electron and ion temperature profiles perform better in the VX model. It is found that the SAT0 model works well at high IP (>0.76 MA) while the VX model covers a wider range of plasma current ( IP > 0.6 MA). The results reported in this paper suggest that the developed integrated modeling could be a candidate for ITER and CFETR ramp-up engineering design modeling.

  15. Human Missions to Near-Earth Asteroids: An Update on NASA's Current Status and Proposed Activities for Small Body Exploration

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Barbee, B. W.; Mink, R. G.; Landis, R. R.; Adamo, D. R.; Johnson, L. N.; Yeomans, D. K.; Reeves, D. M.; Larman, K. T.; hide

    2012-01-01

    Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010.

  16. Two-Dimensional Model Test Study of New Western Breakwater Proposal for Port of Hanstholm

    OpenAIRE

    Eldrup, Mads Røge; Andersen, Thomas Lykke

    2016-01-01

    The present report presents results from a two-dimensional model test study carried out at Aalborg University in December 2016 with the proposed trunk section for the new western breakwater in Port of Hanstholm. The objectives of the model tests were to study the stability of the armour layer, toe erosion, overtopping and transmission. The scale used for the model tests was 1:61.5. Unless otherwise specified all values given in this report are prototype values converted from the model to prot...

  17. Analysis of Eddy Resolving Model of the California Current System

    National Research Council Canada - National Science Library

    Cipriano, Nicholas

    1998-01-01

    A high-resolution, multi-level, primitive equation ocean model is used to investigate the combined role of seasonal wind forcing, thermohaline gradients, and coastline irregularities on the formation...

  18. A Statistical Model of Current Loops and Magnetic Monopoles

    International Nuclear Information System (INIS)

    Ayyer, Arvind

    2015-01-01

    We formulate a natural model of loops and isolated vertices for arbitrary planar graphs, which we call the monopole-dimer model. We show that the partition function of this model can be expressed as a determinant. We then extend the method of Kasteleyn and Temperley-Fisher to calculate the partition function exactly in the case of rectangular grids. This partition function turns out to be a square of a polynomial with positive integer coefficients when the grid lengths are even. Finally, we analyse this formula in the infinite volume limit and show that the local monopole density, free energy and entropy can be expressed in terms of well-known elliptic functions. Our technique is a novel determinantal formula for the partition function of a model of isolated vertices and loops for arbitrary graphs

  19. The Integrated Landscape Modeling partnership - Current status and future directions

    Science.gov (United States)

    Mushet, David M.; Scherff, Eric J.

    2016-01-28

    The Integrated Landscape Modeling (ILM) partnership is an effort by the U.S. Geological Survey (USGS) and U.S. Department of Agriculture (USDA) to identify, evaluate, and develop models to quantify services derived from ecosystems, with a focus on wetland ecosystems and conservation effects. The ILM partnership uses the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling platform to facilitate regional quantifications of ecosystem services under various scenarios of land-cover change that are representative of differing conservation program and practice implementation scenarios. To date, the ILM InVEST partnership has resulted in capabilities to quantify carbon stores, amphibian habitat, plant-community diversity, and pollination services. Work to include waterfowl and grassland bird habitat quality is in progress. Initial InVEST modeling has been focused on the Prairie Pothole Region (PPR) of the United States; future efforts might encompass other regions as data availability and knowledge increase as to how functions affecting ecosystem services differ among regions.The ILM partnership is also developing the capability for field-scale process-based modeling of depressional wetland ecosystems using the Agricultural Policy/Environmental Extender (APEX) model. Progress was made towards the development of techniques to use the APEX model for closed-basin depressional wetlands of the PPR, in addition to the open systems that the model was originally designed to simulate. The ILM partnership has matured to the stage where effects of conservation programs and practices on multiple ecosystem services can now be simulated in selected areas. Future work might include the continued development of modeling capabilities, as well as development and evaluation of differing conservation program and practice scenarios of interest to partner agencies including the USDA’s Farm Service Agency (FSA) and Natural Resources Conservation Service (NRCS). When

  20. Meridional Flow Observations: Implications for the current Flux Transport Models

    International Nuclear Information System (INIS)

    Gonzalez Hernandez, Irene; Komm, Rudolf; Kholikov, Shukur; Howe, Rachel; Hill, Frank

    2011-01-01

    Meridional circulation has become a key element in the solar dynamo flux transport models. Available helioseismic observations from several instruments, Taiwan Oscillation Network (TON), Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI), have made possible a continuous monitoring of the solar meridional flow in the subphotospheric layers for the last solar cycle, including the recent extended minimum. Here we review some of the meridional circulation observations using local helioseismology techniques and relate them to magnetic flux transport models.

  1. Current status of top-specific variant axion model

    Science.gov (United States)

    Chiang, Cheng-Wei; Fukuda, Hajime; Takeuchi, Michihisa; Yanagida, Tsutomu T.

    2018-02-01

    The invisible variant axion model is one of the very attractive models which solves the strong C P problem but does not provoke the domain wall problem. At the electroweak scale, this model requires at least two Higgs doublets, one of which carries a nonzero Peccei-Quinn (PQ) charge and the other is neutral. We consider a scenario where only the right-handed top quark is charged under the PQ symmetry and couples with the PQ-charged Higgs doublet. As a general prediction of this model, the top quark can decay to the observed standard model-like Higgs boson h and the charm or up quark, t →h c /u , which recently exhibited slight excesses at LHC run-I and run-II and will soon be testable at the LHC run-II. If the rare top decay excess stays at the observed central value, we show that tan β ˜1 or smaller is preferred by the Higgs data. The chiral nature of the Higgs flavor-changing interaction is a distinctive feature of this model and testable using the angular distribution of the t →c h decays at the LHC.

  2. Proposal of a Model for effective Management and Development of virtual Teams

    Directory of Open Access Journals (Sweden)

    Petr Skyrik

    2010-10-01

    Full Text Available The main aim of this paper is to present a pilot proposal of a model of “Virtual Development Management System” (ViDeMaS which will facilitate more effective management and development of virtual teams. Management and development of virtual teams is not a simple concept. It comprises a body of knowledge from a number of fields and scientific disciplines. The complexity of the concept may not be simplified as it is absolutely essential for full understanding of its nature. In order to gain better orientation in the concept, different perspectives will be used in the description of the model, which will enable us to achieve the goal of the work and to present the main results of the work (creation of a model for Virtual Development Management System. The present paper thus describes from different perspectives the proposal of a sufficiently detailed and complex model that may be utilized both on theoretical and application level.

  3. DEVELOPING AND PROPOSING A CONCEPTUAL MODEL OF THE FLOW EXPERIENCE DURING ONLINE INFORMATION SEARCH

    Directory of Open Access Journals (Sweden)

    Lazoc Alina

    2012-07-01

    Full Text Available Information search is an essential part of the consumer`s decision making process. The online medium offers new opportunities and challenges for information search activities (in and outside the marketing context. We are interested in the way human information experiences and behaviors are affected by this. Very often online games and social web activities are perceived as challenging, engaging and enjoyable, while online information search is far below this evaluation. Our research proposal implies that using the online medium for information search may provoke enjoyable experiences through the flow state, which may in turn positively influence an individual`s exploratory information behavior and encourage his/her pro-active market behavior. The present study sets out to improve the understanding of the online medium`s impact on human`s exploratory behavior. We hypothesize that the inclusion of the online flow experience in our research model will better explain exploratory information search behaviors. A 11-component conceptual framework is proposed to explain the manifestations of flow, its personal and technological determinants and its behavioral consequence in the context of online information search. Our research has the primary purpose to present an integrated online flow model. Its secondary objective is to stimulate extended research in the area of informational behaviors in the digital age. The paper is organized in three sections. In the first section we briefly report the analysis results of the most relevant online flow theory literature and, drawing on it, we are trying to identify variables and relationships among these. In the second part we propose a research model and use prior flow models to specify a range of testable hypothesis. Drawing on the conceptual model developed, the last section of our study presents the final conclusions and proposes further steps in evaluating the model`s validity. Future research directions

  4. The New Digital Media Value Network: Proposing an Interactive Model of Digital Media Value Activities

    Directory of Open Access Journals (Sweden)

    Sylvia Chan-Olmsted

    2016-07-01

    Full Text Available This study models the dynamic nature of today’s media markets using the framework of value-adding activities in the provision and consumption of media products. The proposed user-centric approach introduces the notion that the actions of external users, social media, and interfaces affect the internal value activities of media firms via a feedback loop, and therefore should themselves be considered value activities. The model also suggests a more comprehensive list of indicators for value assessment.

  5. Space-Time Uncertainty and Cosmology: a Proposed Quantum Model of the Universe [ 245Kb

    Directory of Open Access Journals (Sweden)

    Tosto S.

    2013-10-01

    Full Text Available The paper introduces a cosmological model of the quantum universe. The aim of the model is (i to identify the possible mechanism that governs the matter/antimatter ratio existing in the universe and concurrently to propose (ii a reasonable growth mechanism of the universe and (iii a possible explanation of the dark energy. The concept of timespace uncertainty, on which is based the present quantum approach, has been proven able to bridge quantum mechanics and relativity.

  6. Cigarette smoking and depression comorbidity: systematic review and proposed theoretical model.

    Science.gov (United States)

    Mathew, Amanda R; Hogarth, Lee; Leventhal, Adam M; Cook, Jessica W; Hitsman, Brian

    2017-03-01

    Despite decades of research on co-occurring smoking and depression, cessation rates remain consistently lower for depressed smokers than for smokers in the general population, highlighting the need for theory-driven models of smoking and depression. This paper provides a systematic review with a particular focus upon psychological states that disproportionately motivate smoking in depression, and frame an incentive learning theory account of smoking-depression co-occurrence. We searched PubMed, Scopus, PsychINFO and CINAHL to December 2014, which yielded 852 papers. Using pre-established eligibility criteria, we identified papers focused on clinical issues and motivational mechanisms underlying smoking in established, adult smokers (i.e. maintenance, quit attempts and cessation/relapse) with elevated symptoms of depression. Two reviewers determined independently whether papers met review criteria. We included 297 papers in qualitative synthesis. Our review identified three primary mechanisms that underlie persistent smoking among depressed smokers: low positive affect, high negative affect and cognitive impairment. We propose a novel application of incentive learning theory which posits that depressed smokers experience greater increases in the expected value of smoking in the face of these three motivational states, which promotes goal-directed choice of smoking behavior over alternative actions. The incentive learning theory accounts for current evidence on how depression primes smoking behavior and provides a unique framework for conceptualizing psychological mechanisms of smoking maintenance among depressed smokers. Treatment should focus upon correcting adverse internal states and beliefs about the high value of smoking in those states to improve cessation outcomes for depressed smokers. © 2016 Society for the Study of Addiction.

  7. Comparison of two analytical models of blanking and proposal of a new model

    NARCIS (Netherlands)

    Klingenberg, W; Singh, UP

    With the development of accurate Finite Element models of the punching/blanking process by the present authors and other researchers, important possibilities emerged to model and analyse the process in a research environment. However, Finite Element models are less well suited for use in a

  8. Estimating global, regional and national rotavirus deaths in children aged <5 years: Current approaches, new analyses and proposed improvements.

    Directory of Open Access Journals (Sweden)

    Andrew Clark

    Full Text Available Rotavirus is a leading cause of diarrhoeal mortality in children but there is considerable disagreement about how many deaths occur each year.We compared CHERG, GBD and WHO/CDC estimates of age under 5 years (U5 rotavirus deaths at the global, regional and national level using a standard year (2013 and standard list of 186 countries. The global estimates were 157,398 (CHERG, 122,322 (GBD and 215,757 (WHO/CDC. The three groups used different methods: (i to select data points for rotavirus-positive proportions; (ii to extrapolate data points to individual countries; (iii to account for rotavirus vaccine coverage; (iv to convert rotavirus-positive proportions to rotavirus attributable fractions; and (v to calculate uncertainty ranges. We conducted new analyses to inform future estimates. We found that acute watery diarrhoea was associated with 87% (95% CI 83-90% of U5 diarrhoea hospitalisations based on data from 84 hospital sites in 9 countries, and 65% (95% CI 57-74% of U5 diarrhoea deaths based on verbal autopsy reports from 9 country sites. We reanalysed data from the Global Enteric Multicenter Study (GEMS and found 44% (55% in Asia, and 32% in Africa rotavirus-positivity among U5 acute watery diarrhoea hospitalisations, and 28% rotavirus-positivity among U5 acute watery diarrhoea deaths. 97% (95% CI 95-98% of the U5 diarrhoea hospitalisations that tested positive for rotavirus were entirely attributable to rotavirus. For all clinical syndromes combined the rotavirus attributable fraction was 34% (95% CI 31-36%. This increased by a factor of 1.08 (95% CI 1.02-1.14 when the GEMS results were reanalysed using a more sensitive molecular test.We developed consensus on seven proposals for improving the quality and transparency of future rotavirus mortality estimates.

  9. Dynamic modelling and robust current control of wind-turbine driven DFIG during external AC voltage dip

    Institute of Scientific and Technical Information of China (English)

    HU Jia-bing; HE Yi-kang

    2006-01-01

    Doubly-FedInduction Generator (DFIG), with vector control applied, is widely used in Variable-Speed ConstantFrequency (VSCF) windenergy generation system and shows good performance in maximum wind energy capture. But in two traditional vector control schemes, the equivalent stator magnetizing current is considered invariant in order to simplify the rotor current inner-loop controller. The two schemes can perform very well when the grid is in normal condition. However, when grid disturbance such as grid voltage dip or swell fault occurs, the control performance worsens, the rotor over current occurs and the Fault Ride-Through (FRT) capability of the DFIG wind energy generation system gets seriously deteriorated. An accurate DFIG model was used to deeply investigate the deficiency of the traditional vector control. The improved control schemes of two typical traditional vector control schemes used in DFIG were proposed, and simulation study of the proposed and traditional control schemes, with robust rotor current control using Internal Model Control (IMC) method, was carried out. The validity of the proposed modified schemes to control the rotor current and to improve the FRT capability of the DFIG wind energy generation system was proved by the comparison study.

  10. Finite frequency current noise in the Holstein model

    Science.gov (United States)

    Stadler, P.; Rastelli, G.; Belzig, W.

    2018-05-01

    We investigate the effects of local vibrational excitations in the nonsymmetrized current noise S (ω ) of a nanojunction. For this purpose, we analyze a simple model—the Holstein model—in which the junction is described by a single electronic level that is coupled to two metallic leads and to a single vibrational mode. Using the Keldysh Green's function technique, we calculate the nonsymmetrized current noise to the leading order in the charge-vibration interaction. For the noise associated to the latter, we identify distinct terms corresponding to the mean-field noise and the vertex correction. The mean-field result can be further divided into an elastic correction to the noise and in an inelastic correction, the second one being related to energy exchange with the vibration. To illustrate the general behavior of the noise induced by the charge-vibration interaction, we consider two limit cases. In the first case, we assume a strong coupling of the dot to the leads with an energy-independent transmission, whereas in the second case we assume a weak tunneling coupling between the dot and the leads such that the transport occurs through a sharp resonant level. We find that the noise associated to the vibration-charge interaction shows a complex pattern as a function of the frequency ω and of the transmission function or of the dot's energy level. Several transitions from enhancement to suppression of the noise occurs in different regions, which are determined, in particular, by the vibrational frequency. Remarkably, in the regime of an energy-independent transmission, the zero-order elastic noise vanishes at perfect transmission and at positive frequency, whereas the noise related to the charge-vibration interaction remains finite, enabling the analysis of the pure vibrational-induced current noise.

  11. Interacting loop-current model of superconducting networks

    International Nuclear Information System (INIS)

    Chi, C.C.; Santhanam, P.; Bloechl, P.E.

    1992-01-01

    The authors review their recent approximation scheme to calculate the normal-superconducting phase boundary, T c (H), of a superconducting wire network in a magnetic field in terms of interacting loop currents. The theory is based on the London approximation of the linearized Ginzburg-Landau equation. An approximate general formula is derived for any two-dimensional space-filling lattice comprising tiles of two shapes. Many examples are provided illustrating the use of this method, with a particular emphasis on the fluxoid distribution. In addition to periodic lattices, quasiperiodic lattices and fractal Sierpinski gaskets are also discussed

  12. Assessing the value relevance of current mandatory business model disclosures

    DEFF Research Database (Denmark)

    Schaper, Stefan; Nielsen, Christian; Simoni, Lorenzo

    the model developed by Ohlson (1995). Our results show no significant association between BM disclosure and share prices. The main reason behind this finding can be associated with the low level of disclosure (i.e. the low number of value drivers disclosed on average) by companies as part of their BM......Recent regulations have introduced the requirement for large companies to disclose information about their business model (BM) in the annual reports. The objective of these disclosures is to allow external users to understand better how companies create, deliver and capture value. This study aims...... reports. Ad-hoc created disclosure indexes are based on the taxonomy of business model (BM) configurations developed by Taran et al. (2016) as well as complemented by a frame of reference based on the nice BM canvas elements from Osterwalder and Pigneur (2010). After the classification of companies...

  13. District heating and cogeneration in the EU-28: Current situation, potential and proposed energy strategy for its generalisation

    Directory of Open Access Journals (Sweden)

    Enrique Rosales-Asensio

    2016-10-01

    Full Text Available Yearly, EU-28 conventional thermal generating plants reject a greater amount of energy than what ultimately is utilised by residential and commercial loads for heating and hot water. If this waste heat were to be used through district heating networks, given a previous energy valorisation, there would be a noticeable decrease in imported fossil fuels for heating. As a consequence, benefits in the form of an energy efficiency increase, an energy security improvement, and a minimisation of emitted greenhouse gases would occur. Given that it is not expected for heat demand to decrease significantly in the medium term, district heating networks show the greatest potential for the development of cogeneration. However, to make this happen, some barriers that are far from being technological but are mostly institutional and financial need to be removed. The purpose of this review is to provide information on the potential of using waste heat from conventional thermal power plants (subsequently converted into cogeneration plants in district heating networks located in the EU-28. For this, a preliminary assessment is conducted in order to show an estimate of the cost of adopting an energy strategy in which district heating networks are a major player of the energy mix. From this assessment, it is possible to see that even though the energy strategy proposed in this paper, which is based on a dramatic increase in the joint use of district heating networks and cogeneration, is capital-intensive and would require an annual investment of roughly 300 billion euros, its adoption would result in a reduction of yearly fuel expenses in the order of 100 billion euros and a shortening of about 15% of the total final energy consumption, which makes it of paramount interest as an enabler of the legal basis of the “Secure, Clean and Efficient Energy” future enacted by the EU-28 Horizon 2020.

  14. Taenia solium: current understanding of laboratory animal models of taeniosis.

    Science.gov (United States)

    Flisser, A; Avila, G; Maravilla, P; Mendlovic, F; León-Cabrera, S; Cruz-Rivera, M; Garza, A; Gómez, B; Aguilar, L; Terán, N; Velasco, S; Benítez, M; Jimenez-Gonzalez, D E

    2010-03-01

    Neurocysticercosis is a public health problem in many developing countries and is the most frequent parasitic disease of the brain. The human tapeworm carrier is the main risk factor for acquiring neurocysticercosis. Since the parasite lodges only in the human intestine, experimental models of Taenia solium taeniosis have been explored. Macaques, pigs, dogs, cats and rabbits are unsuccessful hosts even in immunodepressed status. By contrast, rodents are adequate hosts since tapeworms with mature, pregravid and, in some cases, gravid proglottids develop after infection. In this review, information that has been generated with experimental models of taeniosis due to T. solium is discussed. Initially, the use of the model for immunodiagnosis of human taeniosis and evaluation of intervention measures is summarized. Next, descriptions of tapeworms and comparison of hamsters, gerbils and other mammals as experimental models are discussed, as well as data on the humoral immune response, the inflammatory reaction and the production of cytokines associated to Th1 and Th2 responses in the intestinal mucosa. Finally, evaluation of protection induced against the development of tapeworms by recombinant T. solium calreticulin in hamsters is summarized and compared to other studies.

  15. Current Status of Superheat Spray Modeling With NCC

    Science.gov (United States)

    Raju, M. S.; Bulzan, Dan L.

    2012-01-01

    An understanding of liquid fuel behavior at superheat conditions is identified to be a topic of importance in the design of modern supersonic engines. As a part of the NASA's supersonics project office initiative on high altitude emissions, we have undertaken an effort to assess the accuracy of various existing CFD models used in the modeling of superheated sprays. As a part of this investigation, we have completed the implementation of a modeling approach into the national combustion code (NCC), and then applied it to investigate the following three cases: (1) the validation of a flashing jet generated by the sudden release of pressurized R134A from a cylindrical nozzle, (2) the differences between two superheat vaporization models were studied based on both hot and cold flow calculations of a Parker-Hannifin pressure swirl atomizer, (3) the spray characteristics generated by a single-element LDI (Lean Direct Injector) experiment were studied to investigate the differences between superheat and non-superheat conditions. Further details can be found in the paper.

  16. Double-temperature ratchet model and current reversal of coupled Brownian motors

    Science.gov (United States)

    Li, Chen-Pu; Chen, Hong-Bin; Zheng, Zhi-Gang

    2017-12-01

    On the basis of the transport features and experimental phenomena observed in studies of molecular motors, we propose a double-temperature ratchet model of coupled motors to reveal the dynamical mechanism of cooperative transport of motors with two heads, where the interactions and asynchrony between two motor heads are taken into account. We investigate the collective unidirectional transport of coupled system and find that the direction of motion can be reversed under certain conditions. Reverse motion can be achieved by modulating the coupling strength, coupling free length, and asymmetric coefficient of the periodic potential, which is understood in terms of the effective potential theory. The dependence of the directed current on various parameters is studied systematically. Directed transport of coupled Brownian motors can be manipulated and optimized by adjusting the pulsation period or the phase shift of the pulsation temperature.

  17. Statistical models of a gas diffusion electrode: II. Current resistent

    Energy Technology Data Exchange (ETDEWEB)

    Proksch, D B; Winsel, O W

    1965-07-01

    The authors describe an apparatus for measuring the flow resistance of gas diffusion electrodes which is a mechanical analog of the Wheatstone bridge for measuring electric resistance. The flow resistance of a circular DSK electrode sheet, consisting of two covering layers and a working layer between them, was measured as a function of the gas pressure. While the pressure first was increased and then decreased, a hysteresis occurred, which is discussed and explained by a statistical model of a porous electrode.

  18. Review of Current Standard Model Results in ATLAS

    CERN Document Server

    Brandt, Gerhard; The ATLAS collaboration

    2018-01-01

    This talk highlights results selected from the Standard Model research programme of the ATLAS Collaboration at the Large Hadron Collider. Results using data from $p-p$ collisions at $\\sqrt{s}=7,8$~TeV in LHC Run-1 as well as results using data at $\\sqrt{s}=13$~TeV in LHC Run-2 are covered. The status of cross section measurements from soft QCD processes and jet production as well as photon production are presented. The presentation extends to vector boson production with associated jets. Precision measurements of the production of $W$ and $Z$ bosons, including a first measurement of the mass of the $W$ bosons, $m_W$, are discussed. The programme to measure electroweak processes with di-boson and tri-boson final states is outlined. All presented measurements are compatible with Standard Model descriptions and allow to further constrain it. In addition they allow to probe new physics which would manifest through extra gauge couplings, or Standard Model gauge couplings deviating from their predicted value.

  19. Proposal for intake model for workers at IPEN-CNEN/SP who handle 131 I

    International Nuclear Information System (INIS)

    Todo, A.S.; Potiens Junior, A.J.; Gaburo, J.C.; Sanches, M.P.; Oliveira, E.M.

    1997-01-01

    The intake model for the two groups of workers at IPEN-CNEN/SP is presented. They handle iodine compounds during the processing of irradiated targets and at labeling of radiopharmaceutical compounds. The intake model for the workers are proposed from the knowledge of the activities carried out in the plant and the internal monitoring program of the workers. In this study, the intake is considered to be taken uniformly during the days of major activities carried out by the workers. In practice, the application of this model has be shown suitable, for the studied groups

  20. Modelling marine sediment biogeochemistry: Current knowledge gaps, challenges, and some methodological advice for advancement

    DEFF Research Database (Denmark)

    Lessin, Gennadi; Artioli, Yuri; Almroth-Rosell, Elin

    2018-01-01

    The benthic environment is a crucial component of marine systems in the provision of ecosystem services, sustaining biodiversity and in climate regulation, and therefore important to human society. With the contemporary increase in computational power, model resolution and technological improveme......The benthic environment is a crucial component of marine systems in the provision of ecosystem services, sustaining biodiversity and in climate regulation, and therefore important to human society. With the contemporary increase in computational power, model resolution and technological...... improvements in quality and quantity of benthic data, it is necessary to ensure that benthic systems are appropriately represented in coupled benthic-pelagic biogeochemical and ecological modelling studies. In this paper we focus on five topical challenges related to various aspects of modelling benthic...... environments: organic matter reactivity, dynamics of benthic-pelagic boundary layer, microphytobenthos, biological transport and small-scale heterogeneity, and impacts of episodic events. We discuss current gaps in their understanding and indicate plausible ways ahead. Further, we propose a three...

  1. Model of convection mass transfer in titanium alloy at low energy high current electron beam action

    Science.gov (United States)

    Sarychev, V. D.; Granovskii, A. Yu; Nevskii, S. A.; Konovalov, S. V.; Gromov, V. E.

    2017-01-01

    The convection mixing model is proposed for low-energy high-current electron beam treatment of titanium alloys, pre-processed by heterogeneous plasma flows generated via explosion of carbon tape and powder TiB2. The model is based on the assumption vortices in the molten layer are formed due to the treatment by concentrated energy flows. These vortices evolve as the result of thermocapillary convection, arising because of the temperature gradient. The calculation of temperature gradient and penetration depth required solution of the heat problem with taking into account the surface evaporation. However, instead of the direct heat source the boundary conditions in phase transitions were changed in the thermal conductivity equation, assuming the evaporated material takes part in the heat exchange. The data on the penetration depth and temperature distribution are used for the thermocapillary model. The thermocapillary model embraces Navier-Stocks and convection heat transfer equations, as well as the boundary conditions with the outflow of evaporated material included. The solution of these equations by finite elements methods pointed at formation of a multi-vortices structure when electron-beam treatment and its expansion over new zones of material. As the result, strengthening particles are found at the depth exceeding manifold their penetration depth in terms of the diffusion mechanism.

  2. Model-based Optimization and Feedback Control of the Current Density Profile Evolution in NSTX-U

    Science.gov (United States)

    Ilhan, Zeki Okan

    Nuclear fusion research is a highly challenging, multidisciplinary field seeking contributions from both plasma physics and multiple engineering areas. As an application of plasma control engineering, this dissertation mainly explores methods to control the current density profile evolution within the National Spherical Torus eXperiment-Upgrade (NSTX-U), which is a substantial upgrade based on the NSTX device, which is located in Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ. Active control of the toroidal current density profile is among those plasma control milestones that the NSTX-U program must achieve to realize its next-step operational goals, which are characterized by high-performance, long-pulse, MHD-stable plasma operation with neutral beam heating. Therefore, the aim of this work is to develop model-based, feedforward and feedback controllers that can enable time regulation of the current density profile in NSTX-U by actuating the total plasma current, electron density, and the powers of the individual neutral beam injectors. Motivated by the coupled, nonlinear, multivariable, distributed-parameter plasma dynamics, the first step towards control design is the development of a physics-based, control-oriented model for the current profile evolution in NSTX-U in response to non-inductive current drives and heating systems. Numerical simulations of the proposed control-oriented model show qualitative agreement with the high-fidelity physics code TRANSP. The next step is to utilize the proposed control-oriented model to design an open-loop actuator trajectory optimizer. Given a desired operating state, the optimizer produces the actuator trajectories that can steer the plasma to such state. The objective of the feedforward control design is to provide a more systematic approach to advanced scenario planning in NSTX-U since the development of such scenarios is conventionally carried out experimentally by modifying the tokamak's actuator

  3. Transcranial Direct Current Stimulation and behavioral models of smoking addiction

    Directory of Open Access Journals (Sweden)

    Paige eFraser

    2012-08-01

    Full Text Available While few studies have applied transcranial direct current stimulation (tDCS to smoking addiction, existing work suggests that the intervention holds promise for altering the complex system by which environmental cues interact with cravings to drive behavior. Imaging and repetitive transcranial magnetic stimulation (rTMS studies suggest that increased dorsolateral prefrontal cortex (DLPFC activation and integrity may be associated with increased resistance to smoking cues. Anodal tDCS of the DLPFC, believed to boost activation, reduces cravings in response to these cues. The finding that noninvasive stimulation modifies cue induced cravings has profound implications for understanding the processes underlying addiction and relapse. TDCS can also be applied to probe mechanisms underlying and supporting nicotine addiction, as was done in a pharmacologic study that applied nicotine, tDCS, and TMS paired associative stimulation to find that stopping nicotine after chronic use induces a reduction in plasticity, causing difficulty in breaking free from association between cues and cravings. This mini-review will place studies that apply tDCS to smokers in the context of research involving the neural substrates of nicotine addiction.

  4. A proposed model for the transfer of environmental tritium to man and tritium metabolism in model animals

    International Nuclear Information System (INIS)

    Saito, Masahiro; Ishida, M.R.

    1987-01-01

    To evaluate the accumulated dose in human bodies due to the environmental tritium, it is of required to establish an adequate model for the tritium transfer from the environment to man and to obtain enough information on the metabolic behaviour of tritium in animal bodies using model animal system. In this report, first we describe about a proposed model for the transfer of environmental tritium to man and secondly mention briefly about the recent works on the tritium metabolism in newborn animals which have been treated as a model system of tritium intake through food chain. (author)

  5. Modeling space-charge-limited currents in organic semiconductors: Extracting trap density and mobility

    KAUST Repository

    Dacuñ a, Javier; Salleo, Alberto

    2011-01-01

    We have developed and have applied a mobility edge model that takes drift and diffusion currents to characterize the space-charge-limited current in organic semiconductors into account. The numerical solution of the drift-diffusion equation allows

  6. A proposal for operator team behavior model and operator's thinking mechanism

    International Nuclear Information System (INIS)

    Yoshimura, Seiichi; Takano, Kenichi; Sasou, Kunihide

    1995-01-01

    Operating environment in huge systems like nuclear power plants or airplanes is changing rapidly with the advance of computer technology. It is necessary to elucidate thinking process of operators and decision-making process of an operator team in abnormal situations, in order to prevent human errors under such environment. The Central Research Institute of Electric Power Industry is promoting a research project to establish human error prevention countermeasures by modeling and simulating the thinking process of operators and decision-making process of an operator team. In the previous paper, application of multilevel flow modeling was proposed to a mental model which conducts future prediction and cause identification, and the characteristics were verified by experienced plant operators. In this paper, an operator team behavior model and a fundamental operator's thinking mechanism especially 'situation understanding' are proposed, and the proposals are evaluated by experiments using a full-scale simulator. The results reveal that some assumptions such as 'communication is done between a leader and a follower' are almost appropriate and that the situation understanding can be represented by 'probable candidates for cause, determination of a parameter which changes when an event occurs, determination of parameters which are influenced by the change of the previous parameter, determination of a principal parameter and future prediction of the principal parameter'. (author)

  7. Modeling of the electron distribution based on bremsstrahlung emission during lower hybrid current drive on PLT

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, J.E.; von Goeler, S.; Bernabei, S.; Bitter, M.; Chu, T.K.; Efthimion, P.; Fisch, N.; Hooke, W.; Hosea, J.; Jobes, F.

    1985-03-01

    Lower hybrid current drive requires the generation of a high energy electron tail anisotropic in velocity. Measurements of bremsstrahlung emission produced by this tail are compared with the calculated emission from reasonable model distributions. The physical basis and the sensitivity of this modeling process are described and the plasma properties of current driven discharges which can be derived from the model are discussed.

  8. Modeling of the electron distribution based on bremsstrahlung emission during lower hybrid current drive on PLT

    International Nuclear Information System (INIS)

    Stevens, J.E.; von Goeler, S.; Bernabei, S.

    1985-03-01

    Lower hybrid current drive requires the generation of a high energy electron tail anisotropic in velocity. Measurements of bremsstrahlung emission produced by this tail are compared with the calculated emission from reasonable model distributions. The physical basis and the sensitivity of this modeling process are described and the plasma properties of current driven discharges which can be derived from the model are discussed

  9. Fault Modeling and Testing for Analog Circuits in Complex Space Based on Supply Current and Output Voltage

    Directory of Open Access Journals (Sweden)

    Hongzhi Hu

    2015-01-01

    Full Text Available This paper deals with the modeling of fault for analog circuits. A two-dimensional (2D fault model is first proposed based on collaborative analysis of supply current and output voltage. This model is a family of circle loci on the complex plane, and it simplifies greatly the algorithms for test point selection and potential fault simulations, which are primary difficulties in fault diagnosis of analog circuits. Furthermore, in order to reduce the difficulty of fault location, an improved fault model in three-dimensional (3D complex space is proposed, which achieves a far better fault detection ratio (FDR against measurement error and parametric tolerance. To address the problem of fault masking in both 2D and 3D fault models, this paper proposes an effective design for testability (DFT method. By adding redundant bypassing-components in the circuit under test (CUT, this method achieves excellent fault isolation ratio (FIR in ambiguity group isolation. The efficacy of the proposed model and testing method is validated through experimental results provided in this paper.

  10. Short-run and Current Analysis Model in Statistics

    Directory of Open Access Journals (Sweden)

    Constantin Anghelache

    2006-01-01

    Full Text Available Using the short-run statistic indicators is a compulsory requirement implied in the current analysis. Therefore, there is a system of EUROSTAT indicators on short run which has been set up in this respect, being recommended for utilization by the member-countries. On the basis of these indicators, there are regular, usually monthly, analysis being achieved in respect of: the production dynamic determination; the evaluation of the short-run investment volume; the development of the turnover; the wage evolution: the employment; the price indexes and the consumer price index (inflation; the volume of exports and imports and the extent to which the imports are covered by the exports and the sold of trade balance. The EUROSTAT system of indicators of conjuncture is conceived as an open system, so that it can be, at any moment extended or restricted, allowing indicators to be amended or even removed, depending on the domestic users requirements as well as on the specific requirements of the harmonization and integration. For the short-run analysis, there is also the World Bank system of indicators of conjuncture, which is utilized, relying on the data sources offered by the World Bank, The World Institute for Resources or other international organizations statistics. The system comprises indicators of the social and economic development and focuses on the indicators for the following three fields: human resources, environment and economic performances. At the end of the paper, there is a case study on the situation of Romania, for which we used all these indicators.

  11. Short-run and Current Analysis Model in Statistics

    Directory of Open Access Journals (Sweden)

    Constantin Mitrut

    2006-03-01

    Full Text Available Using the short-run statistic indicators is a compulsory requirement implied in the current analysis. Therefore, there is a system of EUROSTAT indicators on short run which has been set up in this respect, being recommended for utilization by the member-countries. On the basis of these indicators, there are regular, usually monthly, analysis being achieved in respect of: the production dynamic determination; the evaluation of the short-run investment volume; the development of the turnover; the wage evolution: the employment; the price indexes and the consumer price index (inflation; the volume of exports and imports and the extent to which the imports are covered by the exports and the sold of trade balance. The EUROSTAT system of indicators of conjuncture is conceived as an open system, so that it can be, at any moment extended or restricted, allowing indicators to be amended or even removed, depending on the domestic users requirements as well as on the specific requirements of the harmonization and integration. For the short-run analysis, there is also the World Bank system of indicators of conjuncture, which is utilized, relying on the data sources offered by the World Bank, The World Institute for Resources or other international organizations statistics. The system comprises indicators of the social and economic development and focuses on the indicators for the following three fields: human resources, environment and economic performances. At the end of the paper, there is a case study on the situation of Romania, for which we used all these indicators.

  12. THE PROPOSED MODEL OF COLLABORATIVE VIRTUAL LEARNING ENVIRONMENT FOR INTRODUCTORY PROGRAMMING COURSE

    Directory of Open Access Journals (Sweden)

    Mahfudzah OTHMAN

    2012-01-01

    Full Text Available This paper discusses the proposed model of the collaborative virtual learning system for the introductory computer programming course which uses one of the collaborative learning techniques known as the “Think-Pair-Share”. The main objective of this study is to design a model for an online learning system that facilitates the collaborative learning activities in a virtual environment such as online communications and pair or small group discussions. In order to model the virtual learning environment, the RUP methodology has been used where it involves the data collection phase and the analysis and design phase. Fifty respondents have been randomly selected to participate in the data collection phase to investigate the students’ interest and learning styles as well as their learning preferences. The results have shown the needs for the development of online small group discussions that can be used as an alternative learning style for programming courses. The proposed design of the virtual learning system named as the Online Collaborative Learning System or OCLS is being depicted using the object-oriented models which are the use-case model and class diagram in order to show the concise processes of virtual “Think-Pair-Share” collaborative activities. The “Think-Pair-Share” collaborative learning technique that is being used in this model has been chosen because of its simplicity and relatively low-risk. This paper also presents the proposed model of the system’s architecture that will become the guidelines for the physical development of OCLS using the web-based applications.

  13. Comparison of bootstrap current and plasma conductivity models applied in a self-consistent equilibrium calculation for Tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Maria Celia Ramos; Ludwig, Gerson Otto [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma]. E-mail: mcr@plasma.inpe.br

    2004-07-01

    Different bootstrap current formulations are implemented in a self-consistent equilibrium calculation obtained from a direct variational technique in fixed boundary tokamak plasmas. The total plasma current profile is supposed to have contributions of the diamagnetic, Pfirsch-Schlueter, and the neoclassical Ohmic and bootstrap currents. The Ohmic component is calculated in terms of the neoclassical conductivity, compared here among different expressions, and the loop voltage determined consistently in order to give the prescribed value of the total plasma current. A comparison among several bootstrap current models for different viscosity coefficient calculations and distinct forms for the Coulomb collision operator is performed for a variety of plasma parameters of the small aspect ratio tokamak ETE (Experimento Tokamak Esferico) at the Associated Plasma Laboratory of INPE, in Brazil. We have performed this comparison for the ETE tokamak so that the differences among all the models reported here, mainly regarding plasma collisionality, can be better illustrated. The dependence of the bootstrap current ratio upon some plasma parameters in the frame of the self-consistent calculation is also analysed. We emphasize in this paper what we call the Hirshman-Sigmar/Shaing model, valid for all collisionality regimes and aspect ratios, and a fitted formulation proposed by Sauter, which has the same range of validity but is faster to compute than the previous one. The advantages or possible limitations of all these different formulations for the bootstrap current estimate are analysed throughout this work. (author)

  14. Disturbed flow mediated modulation of shear forces on endothelial plane: A proposed model for studying endothelium around atherosclerotic plaques

    Science.gov (United States)

    Balaguru, Uma Maheswari; Sundaresan, Lakshmikirupa; Manivannan, Jeganathan; Majunathan, Reji; Mani, Krishnapriya; Swaminathan, Akila; Venkatesan, Saravanakumar; Kasiviswanathan, Dharanibalan; Chatterjee, Suvro

    2016-06-01

    Disturbed fluid flow or modulated shear stress is associated with vascular conditions such as atherosclerosis, thrombosis, and aneurysm. In vitro simulation of the fluid flow around the plaque micro-environment remains a challenging approach. Currently available models have limitations such as complications in protocols, high cost, incompetence of co-culture and not being suitable for massive expression studies. Hence, the present study aimed to develop a simple, versatile model based on Computational Fluid Dynamics (CFD) simulation. Current observations of CFD have shown the regions of modulated shear stress by the disturbed fluid flow. To execute and validate the model in real sense, cell morphology, cytoskeletal arrangement, cell death, reactive oxygen species (ROS) profile, nitric oxide production and disturbed flow markers under the above condition were assessed. Endothelium at disturbed flow region which had been exposed to low shear stress and swirling flow pattern showed morphological and expression similarities with the pathological disturbed flow environment reported previously. Altogether, the proposed model can serve as a platform to simulate the real time micro-environment of disturbed flow associated with eccentric plaque shapes and the possibilities of studying its downstream events.

  15. Generalized Veneziano model for pion scattering off isovector currents and the scaling limit

    CERN Document Server

    Rothe, H J; Rolhe, K D

    1972-01-01

    Starting from a local one-particle approximation scheme for the commutator of two conserved currents, the authors construct a generalized Veneziano model for pion scattering off neutral and charged isovector currents, satisfying the constraints of current conservation and current algebra. The model factorizes correctly on the leading Regge trajectories and incorporates the proper Regge behaviour for strong amplitudes. Fixed poles are found to be present in the s and t channels of the one- and two-current amplitudes. Furthermore, the model makes definite predictions about the structure of Schwinger terms and of the 'seagull' terms in the retarded commutator. (13 refs).

  16. Econometric modelling of Serbian current account determinants: Jackknife Model Averaging approach

    Directory of Open Access Journals (Sweden)

    Petrović Predrag

    2014-01-01

    Full Text Available This research aims to model Serbian current account determinants for the period Q1 2002 - Q4 2012. Taking into account the majority of relevant determinants, using the Jackknife Model Averaging approach, 48 different models have been estimated, where 1254 equations needed to be estimated and averaged for each of the models. The results of selected representative models indicate moderate persistence of the CA and positive influence of: fiscal balance, oil trade balance, terms of trade, relative income and real effective exchange rates, where we should emphasise: (i a rather strong influence of relative income, (ii the fact that the worsening of oil trade balance results in worsening of other components (probably non-oil trade balance of CA and (iii that the positive influence of terms of trade reveals functionality of the Harberger-Laursen-Metzler effect in Serbia. On the other hand, negative influence is evident in case of: relative economic growth, gross fixed capital formation, net foreign assets and trade openness. What particularly stands out is the strong effect of relative economic growth that, most likely, reveals high citizens' future income growth expectations, which has negative impact on the CA.

  17. A debate on current eating disorder diagnoses in light of neurobiological findings: is it time for a spectrum model?

    Directory of Open Access Journals (Sweden)

    Brooks Samantha

    2012-07-01

    Full Text Available Abstract Background Sixty percent of eating disorders do not meet criteria for anorexia- or bulimia nervosa, as defined by the Diagnostic and Statistical Manual version 4 (DSM-IV. Instead they are diagnosed as ‘eating disorders not otherwise specified’ (EDNOS. Discrepancies between criteria and clinical reality currently hampering eating disorder diagnoses in the DSM-IV will be addressed by the forthcoming DSM-V. However, future diagnoses for eating disorders will rely on current advances in the fields of neuroimaging and genetics for classification of symptoms that will ultimately improve treatment. Discussion Here we debate the classification issues, and discuss how brain imaging and genetic discoveries might be interwoven into a model of eating disorders to provide better classification and treatment. The debate concerns: a current issues in the classification of eating disorders in the DSM-IV, b changes proposed for DSM-V, c neuroimaging eating disorder research and d genetic eating disorder research. Summary We outline a novel evidence-based ‘impulse control’ spectrum model of eating disorders. A model of eating disorders is proposed that will aid future diagnosis of symptoms, coinciding with contemporary suggestions by clinicians and the proposed changes due to be published in the DSM-V.

  18. A debate on current eating disorder diagnoses in light of neurobiological findings: is it time for a spectrum model?

    Science.gov (United States)

    2012-01-01

    Background Sixty percent of eating disorders do not meet criteria for anorexia- or bulimia nervosa, as defined by the Diagnostic and Statistical Manual version 4 (DSM-IV). Instead they are diagnosed as ‘eating disorders not otherwise specified’ (EDNOS). Discrepancies between criteria and clinical reality currently hampering eating disorder diagnoses in the DSM-IV will be addressed by the forthcoming DSM-V. However, future diagnoses for eating disorders will rely on current advances in the fields of neuroimaging and genetics for classification of symptoms that will ultimately improve treatment. Discussion Here we debate the classification issues, and discuss how brain imaging and genetic discoveries might be interwoven into a model of eating disorders to provide better classification and treatment. The debate concerns: a) current issues in the classification of eating disorders in the DSM-IV, b) changes proposed for DSM-V, c) neuroimaging eating disorder research and d) genetic eating disorder research. Summary We outline a novel evidence-based ‘impulse control’ spectrum model of eating disorders. A model of eating disorders is proposed that will aid future diagnosis of symptoms, coinciding with contemporary suggestions by clinicians and the proposed changes due to be published in the DSM-V. PMID:22770364

  19. Proposal for a Graded Authorisation Model for the Use of Ionising Radiation in Ireland

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-10-15

    The Radiological Protection Institute of Ireland RPII intends to refocus, streamline and modernise its regulation of the use of ionising radiation in Ireland. This report provides detailed proposals for establishing a graded approach to authorisation in which regulators will be able to focus on higher risk practices by simplifying requirements placed on those of lower risk, without compromising the safety or security of the Irish population. These proposals build on RPII strategic analyses that seek to navigate a course between the competing pressures of public sector reform and the rapid technological changes in medical and nuclear arenas, which challenge the licensing and advisory functions of RPII. A graded approach to authorisation provides the potential for a sustainable basis for future regulation in Ireland. Such an approach would be in line with the forthcoming EURATOM Basic Safety Standards and with general current regulatory trends, which are moving away from one-size-fits-all approaches towards more adaptive, interactive and transparent regulation. In seeking this reform, the RPII also aims to fully utilize the benefits of the internet and electronic communications and to improve the transparency of its processes. These proposals have been developed using a robust, comprehensive project methodology involving a root and branch analysis of current and potential future approaches to authorisation. A series of facilitated workshops were held, punctuated by intensive periods of focused co-enquiry, involving all members of the RPII Regulatory Service. This approach made the fullest use of the decades of expertise and knowledge of these staff. It also provided the platform for developing a common vision of a graded approach to authorisation; for agreeing the criteria for differentiating between levels of authorisation; for collecting the necessary evidence for decision-making and for identifying the implications of these decisions. The graded approach presented

  20. Proposal for a Graded Authorisation Model for the Use of Ionising Radiation in Ireland

    International Nuclear Information System (INIS)

    2012-10-01

    The Radiological Protection Institute of Ireland RPII intends to refocus, streamline and modernise its regulation of the use of ionising radiation in Ireland. This report provides detailed proposals for establishing a graded approach to authorisation in which regulators will be able to focus on higher risk practices by simplifying requirements placed on those of lower risk, without compromising the safety or security of the Irish population. These proposals build on RPII strategic analyses that seek to navigate a course between the competing pressures of public sector reform and the rapid technological changes in medical and nuclear arenas, which challenge the licensing and advisory functions of RPII. A graded approach to authorisation provides the potential for a sustainable basis for future regulation in Ireland. Such an approach would be in line with the forthcoming EURATOM Basic Safety Standards and with general current regulatory trends, which are moving away from one-size-fits-all approaches towards more adaptive, interactive and transparent regulation. In seeking this reform, the RPII also aims to fully utilize the benefits of the internet and electronic communications and to improve the transparency of its processes. These proposals have been developed using a robust, comprehensive project methodology involving a root and branch analysis of current and potential future approaches to authorisation. A series of facilitated workshops were held, punctuated by intensive periods of focused co-enquiry, involving all members of the RPII Regulatory Service. This approach made the fullest use of the decades of expertise and knowledge of these staff. It also provided the platform for developing a common vision of a graded approach to authorisation; for agreeing the criteria for differentiating between levels of authorisation; for collecting the necessary evidence for decision-making and for identifying the implications of these decisions. The graded approach presented

  1. Modeling drain current of indium zinc oxide thin film transistors prepared by solution deposition technique

    Science.gov (United States)

    Qiang, Lei; Liang, Xiaoci; Cai, Guangshuo; Pei, Yanli; Yao, Ruohe; Wang, Gang

    2018-06-01

    Indium zinc oxide (IZO) thin film transistor (TFT) deposited by solution method is of considerable technological interest as it is a key component for the fabrication of flexible and cheap transparent electronic devices. To obtain a principal understanding of physical properties of solution-processed IZO TFT, a new drain current model that account for the charge transport is proposed. The formulation is developed by incorporating the effect of gate voltage on mobility and threshold voltage with the carrier charges. It is demonstrated that in IZO TFTs the below threshold regime should be divided into two sections: EC - EF > 3kT and EC - EF ≤ 3kT, where kT is the thermal energy, EF and EC represent the Fermi level and the conduction band edge, respectively. Additionally, in order to describe conduction mechanisms more accurately, the extended mobility edge model is conjoined, which can also get rid of the complicated and lengthy computations. The good agreement between measured and calculated results confirms the efficiency of this model for the design of integrated large-area thin film circuits.

  2. Current challenges facing the assessment of the allergenic capacity of food allergens in animal models.

    Science.gov (United States)

    Bøgh, Katrine Lindholm; van Bilsen, Jolanda; Głogowski, Robert; López-Expósito, Iván; Bouchaud, Grégory; Blanchard, Carine; Bodinier, Marie; Smit, Joost; Pieters, Raymond; Bastiaan-Net, Shanna; de Wit, Nicole; Untersmayr, Eva; Adel-Patient, Karine; Knippels, Leon; Epstein, Michelle M; Noti, Mario; Nygaard, Unni Cecilie; Kimber, Ian; Verhoeckx, Kitty; O'Mahony, Liam

    2016-01-01

    Food allergy is a major health problem of increasing concern. The insufficiency of protein sources for human nutrition in a world with a growing population is also a significant problem. The introduction of new protein sources into the diet, such as newly developed innovative foods or foods produced using new technologies and production processes, insects, algae, duckweed, or agricultural products from third countries, creates the opportunity for development of new food allergies, and this in turn has driven the need to develop test methods capable of characterizing the allergenic potential of novel food proteins. There is no doubt that robust and reliable animal models for the identification and characterization of food allergens would be valuable tools for safety assessment. However, although various animal models have been proposed for this purpose, to date, none have been formally validated as predictive and none are currently suitable to test the allergenic potential of new foods. Here, the design of various animal models are reviewed, including among others considerations of species and strain, diet, route of administration, dose and formulation of the test protein, relevant controls and endpoints measured.

  3. Extended partially conserved axial-vector current hypothesis and model-dependent results

    International Nuclear Information System (INIS)

    Dominguez, C.A.

    1977-01-01

    The corrections to Goldberger-Treiman relations for ΔS = 0 and vertical-bardeltaSvertical-bar = 1 β decays (Δ/sub π/and Δ/sub K/, respectively) are estimated from a Veneziano-type model for three-point functions. The effect of unitarizing the model is also discussed, and it turns out that Δ/sub π/and Δ/sub K/ are almost insensitive to a variation in the widths of the pseudoscalar-meson daughters. Moreover, the predictions for Δ/sub π/and Δ/sub K/ are in close agreement with experiment. Finally, on-mass-shell extrapolation factors for chiral anomalies in eta → γγ and eta → π + π - γ are also derived, and agreement with experiment is found without the need for invoking eta-eta' mixing. In summary, the model discussed here seems to be a suitable implementation of the recently proposed extended partially conserved axial-vector current hypothesis

  4. THEORETICAL AND EXPERIMENTAL CONTRIBUTIONS CONCERNING THE PROPOSED MODEL FOR THE DISC-TYPED ROTARY ULTRASONIC MOTOR

    Directory of Open Access Journals (Sweden)

    Oana CHIVU

    2010-10-01

    Full Text Available In this work the proposed model for type-disk, ultrasonic motor rotating, elliptic movement to surface beam. A sinusoidal vibration of the vertical displacement in the z-direction, Assume that the vertical displacement of the neutral plane, equals the product of the slope of the neutral plane and half of the beam height, the tangential velocity vs at the upper surface is given.

  5. Current State and Model for Development of Technology-Based Care for Attention Deficit Hyperactivity Disorder

    Science.gov (United States)

    Riley, Steven J.; Calub, Catrina A.; Schweitzer, Julie B.

    2016-01-01

    Abstract Introduction: Care (i.e., evaluation and intervention) delivered through technology is used in many areas of mental health services, including for persons with attention deficit hyperactivity disorder (ADHD). Technology can facilitate care for individuals with ADHD, their parents, and their care providers. The adoption of technological tools for ADHD care requires evidence-based studies to support the transition from development to integration into use in the home, school, or work for persons with the disorder. The initial phase, which is development of technological tools, has begun in earnest; however, the evidence base for many of these tools is lacking. In some instances, the uptake of a piece of technology into home use or clinical practice may be further along than the research to support its use. Methods: In this study, we review the current evidence regarding technology for ADHD and also propose a model to evaluate the support for other tools that have yet to be tested. Results: We propose using the Research Domain Criteria as a framework for evaluating the tools' relationships to dimensions related to ADHD. Conclusion: This article concludes with recommendations for testing new tools that may have promise in improving the evaluation or treatment of persons with ADHD. PMID:26985703

  6. Stress, autonomic imbalance, and the prediction of metabolic risk: A model and a proposal for research.

    Science.gov (United States)

    Wulsin, Lawson; Herman, James; Thayer, Julian F

    2018-03-01

    Devising novel prevention strategies for metabolic disorders will depend in part on the careful elucidation of the common pathways for developing metabolic risks. The neurovisceral integration model has proposed that autonomic imbalance plays an important role in the pathway from acute and chronic stress to cardiovascular disease. Though generally overlooked by clinicians, autonomic imbalance (sympathetic overactivity and/or parasympathetic underactivity) can be measured and modified by methods that are available in primary care. This review applies the neurovisceral integration concept to the clinical setting by proposing that autonomic imbalance plays a primary role in the development of metabolic risks. We present a testable model, a systematic review of the evidence in support of autonomic imbalance as a predictor for metabolic risks, and specific approaches to test this model as a guide to future research on the role of stress in metabolic disorders. We propose that autonomic imbalance deserves consideration by researchers, clinicians, and policymakers as a target for early interventions to prevent metabolic disorders. Published by Elsevier Ltd.

  7. A proposed defect tracking model for classifying the inserted defect reports to enhance software quality control.

    Science.gov (United States)

    Sultan, Torky; Khedr, Ayman E; Sayed, Mostafa

    2013-01-01

    NONE DECLARED Defect tracking systems play an important role in the software development organizations as they can store historical information about defects. There are many research in defect tracking models and systems to enhance their capabilities to be more specifically tracking, and were adopted with new technology. Furthermore, there are different studies in classifying bugs in a step by step method to have clear perception and applicable method in detecting such bugs. This paper shows a new proposed defect tracking model for the purpose of classifying the inserted defects reports in a step by step method for more enhancement of the software quality.

  8. [Impact of small-area context on health: proposing a conceptual model].

    Science.gov (United States)

    Voigtländer, S; Mielck, A; Razum, O

    2012-11-01

    Recent empirical studies stress the impact of features related to the small-area context on individual health. However, so far there exists no standard explanatory model that integrates the different kinds of such features and that conceptualises their relation to individual characteristics of social inequality. A review of theoretical publications on the relationship between social position and health as well as existing conceptual models for the impact of features related to the small-area context on health was undertaken. In the present article we propose a conceptual model for the health impact of the small-area context. This model conceptualises the location of residence as one dimension of social inequality that affects health through the resources as well as stressors which are inherent in the small-area context. The proposed conceptual model offers an orientation for future empirical studies and can serve as a basis for further discussions concerning the health relevance of the small-area context. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Assessment of nutritional status in the elderly: a proposed function-driven model.

    Science.gov (United States)

    Engelheart, Stina; Brummer, Robert

    2018-01-01

    There is no accepted or standardized definition of 'malnutrition'. Hence, there is also no definition of what constitutes an adequate nutritional status. In elderly people, assessment of nutritional status is complex and is complicated by multi-morbidity and disabilities combined with nutrition-related problems, such as dysphagia, decreased appetite, fatigue, and muscle weakness. We propose a nutritional status model that presents nutritional status from a comprehensive functional perspective. This model visualizes the complexity of the nutritional status in elderly people. The presented model could be interpreted as the nutritional status is conditional to a person's optimal function or situation. Another way of looking at it might be that a person's nutritional status affects his or her optimal situation. The proposed model includes four domains: (1) physical function and capacity; (2) health and somatic disorders; (3) food and nutrition; and (4) cognitive, affective, and sensory function. Each domain has a major impact on nutritional status, which in turn has a major impact on the outcome of each domain. Nutritional status is a multifaceted concept and there exist several knowledge gaps in the diagnosis, prevention, and optimization of treatment of inadequate nutritional status in elderly people. The nutritional status model may be useful in nutritional assessment research, as well as in the clinical setting.

  10. A proposed model of psychodynamic psychotherapy linked to Erik Erikson's eight stages of psychosocial development.

    Science.gov (United States)

    Knight, Zelda Gillian

    2017-09-01

    Just as Freud used stages of psychosexual development to ground his model of psychoanalysis, it is possible to do the same with Erik Erikson's stages of development with regards to a model of psychodynamic psychotherapy. This paper proposes an eight-stage model of psychodynamic psychotherapy linked to Erik Erikson's eight stages of psychosocial development. Various suggestions are offered. One such suggestion is that as each of Erikson's developmental stages is triggered by a crisis, in therapy it is triggered by the client's search. The resolution of the search often leads to the development of another search, which implies that the therapy process comprises a series of searches. This idea of a series of searches and resolutions leads to the understanding that identity is developmental and therapy is a space in which a new sense of identity may emerge. The notion of hope is linked to Erikson's stage of Basic Trust and the proposed model of therapy views hope and trust as essential for the therapy process. Two clinical vignettes are offered to illustrate these ideas. Psychotherapy can be approached as an eight-stage process and linked to Erikson's eight stages model of development. Psychotherapy may be viewed as a series of searches and thus as a developmental stage resolution process, which leads to the understanding that identity is ongoing throughout the life span. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Energetic models: a proposal of integrated planning; Modelos energeticos: uma proposta de planejamento integrado

    Energy Technology Data Exchange (ETDEWEB)

    Pereira Junior, Amaro Olimpio; Soares, Jeferson Borghetti; Araujo, Mauro Almeida [Empresa de Pesquisa Energetica (EPE), Brasilia, DF (Brazil)]. E-mails: amaro.pereira@epe.gov.br; jeferson.soares@epe.gov.br; mauro.almeida@epe.gov.br; La Rovere, Emilio Lebre [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Planejamento Estrategico]. E-mail: emilio@ppe.ufrj.br; Costa, Ricardo Cunha da [Banco Nacional de Desenvolvimento Economico e Social (BNDES), Rio de Janeiro, RJ (Brazil)]. E-mail: rcco@bndes.gov.br

    2006-07-01

    Top-down, bottom-up and hybrid models for representing energy system are often used in energy planning. However, in developing countries some of their assumptions do not apply: markets are not developed and not competitive; informal economies are representative; there are huge social inequalities; regulatory changes are not completed; there exist constraints to capital flow; etc. All theses problems need to be well represented in order to have energy analysis more consistent. In this work, it is proposed a multi-sector dynamic recursive model that incorporates consumer behaviors, energy policies, technical progress and factors of production substitution. The static result feeds detailed energy models that provide updated values for the next step equilibrium. This approach takes advantages not only in terms of computation but also in terms of the consistence between economy and energy modeling. (author)

  12. IMPROVING MODEL OF CHANNEL AIRBORN ELECTRICAL POWER SYSTEM OF ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Yu. P. Artemenko

    2015-01-01

    Full Text Available This article is devoted to math modeling of channel of alternating current airborne electrical power-supply system. Mathematical modeling of generator, voltage regulator, constant speed drive is considered.

  13. Modeling and control of the output current of a Reformed Methanol Fuel Cell system

    DEFF Research Database (Denmark)

    Justesen, Kristian Kjær; Andreasen, Søren Juhl; Pasupathi, Sivakumar

    2015-01-01

    In this work, a dynamic Matlab SIMULINK model of the relationship between the fuel cell current set point of a Reformed Methanol Fuel Cell system and the output current of the system is developed. The model contains an estimated fuel cell model, based on a polarization curve and assumed first order...... dynamics, as well as a battery model based on an equivalent circuit model and a balance of plant power consumption model. The models are tuned with experimental data and verified using a verification data set. The model is used to develop an output current controller which can control the charge current...... of the battery. The controller is a PI controller with feedforward and anti-windup. The performance of the controller is tested and verified on the physical system....

  14. Positive feedback : exploring current approaches in iterative travel demand model implementation.

    Science.gov (United States)

    2012-01-01

    Currently, the models that TxDOTs Transportation Planning and Programming Division (TPP) developed are : traditional three-step models (i.e., trip generation, trip distribution, and traffic assignment) that are sequentially : applied. A limitation...

  15. Vacuum circuit breaker postarc current modelling based on the theory of Langmuir probes

    NARCIS (Netherlands)

    Lanen, van E.P.A.; Smeets, R.; Popov, M.; Sluis, van der L.

    2007-01-01

    High-resolution measurements on the postarc current in vacuum circuit breakers (VCBs) reveal a period, immediately following current-zero, in which the voltage remains practically zero. The most widely used model for simulating the interaction between the postarc current with the electrical circuit

  16. [Social determinants of odontalgia in epidemiological studies: theoretical review and proposed conceptual model].

    Science.gov (United States)

    Bastos, João Luiz Dornelles; Gigante, Denise Petrucci; Peres, Karen Glazer; Nedel, Fúlvio Borges

    2007-01-01

    The epidemiological literature has been limited by the absence of a theoretical framework reflecting the complexity of causal mechanisms for the occurrence of health phenomena / disease conditions. In the field of oral epidemiology, such lack of theory also prevails, since dental caries the leading topic in oral research has been often studied through a biological and reductionist viewpoint. One of the most important consequences of dental caries is dental pain (odontalgia), which has received little attention in studies with sophisticated theoretical models and powerful designs to establish causal relationships. The purpose of this study is to review the scientific literature on the determinants of odontalgia and to discuss theories proposed for the explanation of the phenomenon. Conceptual models and emerging theories on the social determinants of oral health are revised, in an attempt to build up links with the bio-psychosocial pain model, proposing a more elaborate causal model for odontalgia. The framework suggests causal pathways between social structure and oral health through material, psychosocial and behavioral pathways. Aspects of the social structure are highlighted in order to relate them to odontalgia, stressing their importance in discussions of causal relationships in oral health research.

  17. The spherical segmented Langmuir probe in a flowing thermal plasma: numerical model of the current collection

    Directory of Open Access Journals (Sweden)

    E. Séran

    2005-07-01

    Full Text Available The segmented Langmuir probe (SLP has been recently proposed by one of the authors (Lebreton, 2002 as an instrument to derive the bulk velocity of terrestrial or planetary plasmas, in addition to the electron density and temperature that are routinely measured by Langmuir probes. It is part of the scientific payload on the DEMETER micro-satellite developed by CNES. The basic concept of this probe is to measure the current distribution over the surface using independent collectors under the form of small spherical caps and to use the angular anisotropy of these currents to obtain the plasma bulk velocity in the probe reference frame. In order to determine the SLP capabilities, we have developed a numerical PIC (Particles In Cell model which provides a tool to compute the distribution of the current collected by a spherical probe. Our model is based on the simultaneous determination of the charge densities in the probe sheath and on the probe surface, from which the potential distribution in the sheath region can be obtained. This method is well adapted to the SLP problem and has some advantages since it provides a natural control of the charge neutrality inside the simulation box, allows independent mesh sizes in the sheath and on the probe surface, and can be applied to complex surfaces. We present in this paper initial results obtained for plasma conditions corresponding to a Debye length equal to the probe radius. These plasma conditions are observed along the Demeter orbit. The model results are found to be in very good agreement with those published by Laframboise (1966 for a spherical probe in a thermal non-flowing plasma. This demonstrates the adequacy of the computation method and of the adjustable numerical parameters (size of the numerical box and mesh, time step, number of macro-particles, etc. for the considered plasma-probe configuration. We also present the results obtained in the case of plasma flowing with mesothermal conditions

  18. The spherical segmented Langmuir probe in a flowing thermal plasma: numerical model of the current collection

    Directory of Open Access Journals (Sweden)

    E. Séran

    2005-07-01

    Full Text Available The segmented Langmuir probe (SLP has been recently proposed by one of the authors (Lebreton, 2002 as an instrument to derive the bulk velocity of terrestrial or planetary plasmas, in addition to the electron density and temperature that are routinely measured by Langmuir probes. It is part of the scientific payload on the DEMETER micro-satellite developed by CNES. The basic concept of this probe is to measure the current distribution over the surface using independent collectors under the form of small spherical caps and to use the angular anisotropy of these currents to obtain the plasma bulk velocity in the probe reference frame. In order to determine the SLP capabilities, we have developed a numerical PIC (Particles In Cell model which provides a tool to compute the distribution of the current collected by a spherical probe. Our model is based on the simultaneous determination of the charge densities in the probe sheath and on the probe surface, from which the potential distribution in the sheath region can be obtained. This method is well adapted to the SLP problem and has some advantages since it provides a natural control of the charge neutrality inside the simulation box, allows independent mesh sizes in the sheath and on the probe surface, and can be applied to complex surfaces. We present in this paper initial results obtained for plasma conditions corresponding to a Debye length equal to the probe radius. These plasma conditions are observed along the Demeter orbit. The model results are found to be in very good agreement with those published by Laframboise (1966 for a spherical probe in a thermal non-flowing plasma. This demonstrates the adequacy of the computation method and of the adjustable numerical parameters (size of the numerical box and mesh, time step, number of macro-particles, etc. for the considered plasma-probe configuration. We also present the results obtained in the case of plasma flowing with mesothermal conditions

  19. Proposal of custom made wrist orthoses based on 3D modelling and 3D printing.

    Science.gov (United States)

    Abreu de Souza, Mauren; Schmitz, Cristiane; Marega Pinhel, Marcelo; Palma Setti, Joao A; Nohama, Percy

    2017-07-01

    Accessibility to three-dimensional (3D) technologies, such as 3D scanning systems and additive manufacturing (like 3D printers), allows a variety of 3D applications. For medical applications in particular, these modalities are gaining a lot of attention enabling several opportunities for healthcare applications. The literature brings several cases applying both technologies, but none of them focus on the spreading of how this technology could benefit the health segment. This paper proposes a new methodology, which employs both 3D modelling and 3D printing for building orthoses, which could better fit the demands of different patients. Additionally, there is an opportunity for sharing expertise, as it represents a trendy in terms of the maker-movement. Therefore, as a result of the proposed approach, we present a case study based on a volunteer who needs an immobilization orthosis, which was built for exemplification of the whole process. This proposal also employs freely available 3D models and software, having a strong social impact. As a result, it enables the implementation and effective usability for a variety of built to fit solutions, hitching useful and smarter technologies for the healthcare sector.

  20. Modeling and control of the current density profile in Tokamaks and its relation to electron transport

    International Nuclear Information System (INIS)

    Zucca, C.

    2009-04-01

    transport properties should occur. The aim of the study regarding the ITER project has been to analyse the capabilities of a possible variant of the EC system, recently proposed with the intent to optimize the combined action of the Upper and Equatorial EC Launchers and, therefore, to allow a broader operational domain for ITER. This variant will maintain the main goals for which the ITER EC system has originally been designed, namely the stabilization of Neoclassical Tearing Modes (NTMs) and of the sawtooth instability. This is a necessary feature that has been carefully analyzed in the present study. Besides allowing excellent performance in controlling NTMs and the sawtooth period, the suggested variant paves a way for further exploitation of EC waves for ITER. The present ITER base-line design has all EC launchers providing only co-ECCD. The performed numerical modeling has shown that the possibility to drive counter-ECCD with one of the three rows of equatorial mirrors offers greater control of the plasma current density. The counter-ECCD may also be balanced with co-ECCD to provide pure EC heating, with no net driven current. This would be an additional asset if EC waves were found to be needed to assist the L-H transition during plasma ramp-up. The overall decrease in co-ECCD, by turning one row to counter-ECCD, is estimated to be negligible, because the difference between full off-axis co-ECCD using all 20 MW from the Equatorial Launcher or co-ECCD driven by 2/3 from the Equatorial Launcher and 1/3 from the Upper Launcher is small. Therefore the latter analysis provides, in our opinion, a strong evidence of the substantial gain in flexibility if the suggested variant of the ITER EC system were accepted as the base-line design. (author)

  1. A Proposed Analytical Model for Integrated Pick-and-Sort Systems

    Directory of Open Access Journals (Sweden)

    Recep KIZILASLAN

    2013-11-01

    Full Text Available In this study we present an analytical approach for integration of order picking and sortation operations which are the most important, labour intensive and costly activity for warehouses. Main aim is to investigate order picking and sorting efficiencies under different design issues as a function of order wave size. Integrated analytical model is proposed to estimate the optimum order picking and order sortation efficiency. The model, which has been tested by simulations with different illustrative examples, calculates the optimum wave size that solves the trade-off between picking and sorting operations and makes the order picking and sortations efficiency maximum. Our model also allow system designer to predict the order picking and sorting capacity for different system configurations. This study presents an innovative approach for integrated warehouse operations.

  2. Nanometrology, Standardization and Regulation of Nanomaterials in Brazil: A Proposal for an Analytical-Prospective Model

    Directory of Open Access Journals (Sweden)

    Ana Rusmerg Giménez Ledesma

    2013-05-01

    Full Text Available The main objective of this paper is to propose an analytical-prospective model as a tool to support decision-making processes concerning metrology, standardization and regulation of nanomaterials in Brazil, based on international references and ongoing initiatives in the world. In the context of nanotechnology development in Brazil, the motivation for carrying out this research was to identify potential benefits of metrology, standardization and regulation of nanomaterials production, from the perspective of future adoption of the model by the main stakeholders of development of these areas in Brazil. The main results can be summarized as follows: (i an overview of international studies on metrology, standardization and regulation of nanomaterials, and nanoparticles, in special; (ii the analytical-prospective model; and (iii the survey questionnaire and the roadmapping tool for metrology, standardization and regulation of nanomaterials in Brazil, based on international references and ongoing initiatives in the world.

  3. Proposed model for fuel-coolant mixing during a core-melt accident

    International Nuclear Information System (INIS)

    Corradini, M.L.

    1983-01-01

    If complete failure of normal and emergency coolant flow occurs in a light water reactor, fission product decay heat would eventually cause melting of the reactor fuel and cladding. The core melt may then slump into the lower plenum and later into the reactor cavity and contact residual liquid water. A model is proposed to describe the fuel-coolant mixing process upon contact. The model is compared to intermediate scale experiments being conducted at Sandia. The modelling of this mixing process will aid in understanding three important processes: (1) fuel debris sizes upon quenching in water, (2) the hydrogen source term during fuel quench, and (3) the rate of steam production. Additional observations of Sandia data indicate that the steam explosion is affected by this mixing process

  4. Emerging identities: A proposed model for an interactive science curriculum for First Nations students

    Science.gov (United States)

    Sable, Trudy

    Mi'kmaw students face a complexity of personal, cultural, and social conditions within contemporary educational systems that affect their continued participation in the educational process offered within Atlantic Canada. Despite a variety of approaches developed by educators to address the high drop out rate and lack of interest in science, the statistics remain largely unchanged. Aboriginal educators are calling for a "new story" in education that better meets the needs of Aboriginal students. This study attempts to identify the conditions and contexts necessary to bridge the gap that currently exists for Aboriginal students in science studies. The research investigates the basic relationship between learning in general and the meaning-making processes engaged in by students of a Grade 7/8 class within a Mi'kmaw reserve school. It leads to a proposal for an alternative pedagogy, or a new narrative, for teaching science to Aboriginal students and the foundations for a culturally interactive science curriculum. For educators to understand the complexity of issues affecting Mi'kmaw student achievement in science requires a theoretical framework that allows the students' lived experience to emerge. Toward this end, the research includes both phenomenological and ethnographic approaches to understanding the lived experiences and cultural narratives based on interviews with the students, a field trip within the community, and a trial chemistry lesson. I examined how these students perceive themselves in different contexts and how their sense of identity establishes the meaningfulness of particular educational content. I also assessed how person, community/cultural and social contexts affect the students' learning. Part of creating this new narrative requires recognizing knowledge, including science, as a cultural product Taking this cultural view of scientific knowledge allows us to view learning as a process of identity formation and culture as a system of symbols

  5. Proposal of a congestion control technique in LAN networks using an econometric model ARIMA

    Directory of Open Access Journals (Sweden)

    Joaquín F Sánchez

    2017-01-01

    Full Text Available Hasty software development can produce immediate implementations with source code unnecessarily complex and hardly readable. These small kinds of software decay generate a technical debt that could be big enough to seriously affect future maintenance activities. This work presents an analysis technique for identifying architectural technical debt related to non-uniformity of naming patterns; the technique is based on term frequency over package hierarchies. The proposal has been evaluated on projects of two popular organizations, Apache and Eclipse. The results have shown that most of the projects have frequent occurrences of the proposed naming patterns, and using a graph model and aggregated data could enable the elaboration of simple queries for debt identification. The technique has features that favor its applicability on emergent architectures and agile software development.

  6. Organizational intellectual capital and the role of the nurse manager: A proposed conceptual model.

    Science.gov (United States)

    Gilbert, Jason H; Von Ah, Diane; Broome, Marion E

    Nurse managers must leverage both the human capital and social capital of the teams they lead in order to produce quality outcomes. Little is known about the relationship between human capital and social capital and how these concepts may work together to produce organizational outcomes through leadership of nurses. The purpose of this article was to explore the concepts of human capital and social capital as they relate to nursing leadership in health care organizations. Specific aims included (a) to synthesize the literature related to human capital and social capital in leadership, (b) to refine the conceptual definitions of human capital and social capital with associated conceptual antecedents and consequences, and (c) to propose a synthesized conceptual model guiding further empirical research of social capital and human capital in nursing leadership. A systematic integrative review of leadership literature using criteria informed by Whittemore and Knafl (2005) was completed. CINAHL Plus with Full Text, Academic Search Premier, Business Source Premier, Health Business FullTEXT, MEDLINE, and PsychINFO databases were searched for the years 1995 to 2016 using terms "human capital," "social capital," and "management." Analysis of conceptual definitions, theoretical and conceptual models, antecedents and consequences, propositions or hypotheses, and empirical support for 37 articles fitting review criteria resulted in the synthesis of the proposed Gilbert Conceptual Model of Organizational Intellectual Capital. The Gilbert Conceptual Model of Organizational Intellectual Capital advances the propositions of human capital theory and social capital theory and is the first model to conceptualize the direct and moderating effects that nurse leaders have on the human capital and social capital of the teams they lead. This model provides a framework for further empirical study and may have implications for practice, organizational policy, and education related to nursing

  7. Analysis of Expediency to Apply LCL Model with Source of Higher Harmonics of Current While Investigating Resonance Condition of Power Supply Network

    OpenAIRE

    M. Pavlovsky; A. Shimansky; Z. Fialkovsky

    2004-01-01

    The paper considers a power system model of a plant with one capacitor bank and with one current source of higher harmonics for higher power factor. The laboratory research results of this system and practical application of the proposed model are given in the paper.

  8. Analysis of Expediency to Apply LCL Model with Source of Higher Harmonics of Current While Investigating Resonance Condition of Power Supply Network

    Directory of Open Access Journals (Sweden)

    M. Pavlovsky

    2004-01-01

    Full Text Available The paper considers a power system model of a plant with one capacitor bank and with one current source of higher harmonics for higher power factor. The laboratory research results of this system and practical application of the proposed model are given in the paper.

  9. Self-rated health, multimorbidity and depression in Mexican older adults: Proposal and evaluation of a simple conceptual model.

    Science.gov (United States)

    Bustos-Vázquez, Eduardo; Fernández-Niño, Julián Alfredo; Astudillo-Garcia, Claudia Iveth

    2017-04-01

    Self-rated health is an individual and subjective conceptualization involving the intersection of biological, social and psychological factors. It provides an invaluable and unique evaluation of a person's general health status. To propose and evaluate a simple conceptual model to understand self-rated health and its relationship to multimorbidity, disability and depressive symptoms in Mexican older adults. We conducted a cross-sectional study based on a national representative sample of 8,874 adults of 60 years of age and older. Self-perception of a positive health status was determined according to a Likert-type scale based on the question: "What do you think is your current health status?" Intermediate variables included multimorbidity, disability and depressive symptoms, as well as dichotomous exogenous variables (sex, having a partner, participation in decision-making and poverty). The proposed conceptual model was validated using a general structural equation model with a logit link function for positive self-rated health. A direct association was found between multimorbidity and positive self-rated health (OR=0.48; 95% CI: 0.42-0.55), disability and positive self-rated health (OR=0.35; 95% CI: 0.30-0.40), depressive symptoms and positive self-rated health (OR=0.38; 95% CI: 0.34-0.43). The model also validated indirect associations between disability and depressive symptoms (OR=2.25; 95% CI: 2.01- 2.52), multimorbidity and depressive symptoms (OR=1.79; 95% CI: 1.61-2.00) and multimorbidity and disability (OR=1.98; 95% CI: 1.78-2.20). A parsimonious theoretical model was empirically evaluated, which enabled identifying direct and indirect associations with positive self-rated health.

  10. A self-discharge model of Lithium-Sulfur batteries based on direct shuttle current measurement

    DEFF Research Database (Denmark)

    Knap, Vaclav; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

    2016-01-01

    . A simple but comprehensive mathematical model of the Li-S battery cell self-discharge based on the shuttle current was developed and is presented. The shuttle current values for the model parameterization were obtained from the direct shuttle current measurements. Furthermore, the battery cell depth......-of-discharge values were recomputed in order to account for the influence of the self-discharge and provide a higher accuracy of the model. Finally, the derived model was successfully validated against laboratory experiments at various conditions....

  11. Proposal for a model for competitiveness analysis in environmental sustainability in automotive segment companies

    Directory of Open Access Journals (Sweden)

    Luís Henrique Rodrigues

    2018-06-01

    Full Text Available The competitive landscape for companies has been changing over time, featuring an increase in competitiveness in cost, quality, reliability, agility and more recently by a concern for environmental and social factors. This work aims to propose an exploratory analysis model to evaluate companies’ sustainability competitiveness. The model proposes the grouping of companies into clusters, ranking them according to the adoption of lean manufacturing practices, environmental management and human resources, and allocating them into quadrants according to the higher or lower production of waste in their manufacturing processes. The adherence to the model is made with a sample of automotive segment companies (auto parts and motor vehicle manufacturers. The work is classified as one of a practical nature, exploratory, qualitative, and using the survey method. The conclusion that 37.5% of auto parts companies are grouped into clusters that lead to the reduction of waste, with practices in lean manufacturing and environmental management which adjust to competitive factors in the sustainability of motor vehicle manufacturers, is noteworthy.

  12. Modeling fault rupture hazard for the proposed repository at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Coppersmith, K.J.; Youngs, R.R.

    1992-01-01

    In this paper as part of the Electric Power Research Institute's High Level Waste program, the authors have developed a preliminary probabilistic model for assessing the hazard of fault rupture to the proposed high level waste repository at Yucca Mountain. The model is composed of two parts: the earthquake occurrence model that describes the three-dimensional geometry of earthquake sources and the earthquake recurrence characteristics for all sources in the site vicinity; and the rupture model that describes the probability of coseismic fault rupture of various lengths and amounts of displacement within the repository horizon 350 m below the surface. The latter uses empirical data from normal-faulting earthquakes to relate the rupture dimensions and fault displacement amounts to the magnitude of the earthquake. using a simulation procedure, we allow for earthquake occurrence on all of the earthquake sources in the site vicinity, model the location and displacement due to primary faults, and model the occurrence of secondary faulting in conjunction with primary faulting

  13. Proposed Core Competencies and Empirical Validation Procedure in Competency Modeling: Confirmation and Classification.

    Science.gov (United States)

    Baczyńska, Anna K; Rowiński, Tomasz; Cybis, Natalia

    2016-01-01

    Competency models provide insight into key skills which are common to many positions in an organization. Moreover, there is a range of competencies that is used by many companies. Researchers have developed core competency terminology to underline their cross-organizational value. The article presents a theoretical model of core competencies consisting of two main higher-order competencies called performance and entrepreneurship. Each of them consists of three elements: the performance competency includes cooperation, organization of work and goal orientation, while entrepreneurship includes innovativeness, calculated risk-taking and pro-activeness. However, there is lack of empirical validation of competency concepts in organizations and this would seem crucial for obtaining reliable results from organizational research. We propose a two-step empirical validation procedure: (1) confirmation factor analysis, and (2) classification of employees. The sample consisted of 636 respondents (M = 44.5; SD = 15.1). Participants were administered a questionnaire developed for the study purpose. The reliability, measured by Cronbach's alpha, ranged from 0.60 to 0.83 for six scales. Next, we tested the model using a confirmatory factor analysis. The two separate, single models of performance and entrepreneurial orientations fit quite well to the data, while a complex model based on the two single concepts needs further research. In the classification of employees based on the two higher order competencies we obtained four main groups of employees. Their profiles relate to those found in the literature, including so-called niche finders and top performers. Some proposal for organizations is discussed.

  14. A Proposed Model for Selecting Measurement Procedures for the Assessment and Treatment of Problem Behavior.

    Science.gov (United States)

    LeBlanc, Linda A; Raetz, Paige B; Sellers, Tyra P; Carr, James E

    2016-03-01

    Practicing behavior analysts frequently assess and treat problem behavior as part of their ongoing job responsibilities. Effective measurement of problem behavior is critical to success in these activities because some measures of problem behavior provide more accurate and complete information about the behavior than others. However, not every measurement procedure is appropriate for every problem behavior and therapeutic circumstance. We summarize the most commonly used measurement procedures, describe the contexts for which they are most appropriate, and propose a clinical decision-making model for selecting measurement produces given certain features of the behavior and constraints of the therapeutic environment.

  15. Proposing a Model for Patient Admission and NFC Mobile Payment by Biometric Identification and Smart Health Card

    Directory of Open Access Journals (Sweden)

    Mahdi Barkhordari Firouzabadi

    2016-02-01

    Full Text Available Abstract Following the advances in mobile communication and information technology, smart phones have been used in a wide variety of commercial, social, entertainment, file sharing and health transactions and applications. The current procedures in healthcare environment for patient registration, appointment scheduling and payment are time consuming and somehow tiresome. Traditionally, patients were supposed to fill out registration forms, wait for being called, and finally stand in long lines for payment procedures. In some places, appointment could be done online via web but still the patient has to walk in with appointment card and in our case, provide the insurance booklet to the front desk personnel to pay for services and receive discounts for insurance. Therefore, the present study intended to propose a model using Near Field Communication-enabled mobile application for a medical clinic which currently offers online and call services for making an appointment, though patient waiting time is still too much in the current process of payment for services.

  16. Preclinical QSP Modeling in the Pharmaceutical Industry: An IQ Consortium Survey Examining the Current Landscape

    Science.gov (United States)

    Wu, Fan; Bansal, Loveleena; Bradshaw‐Pierce, Erica; Chan, Jason R.; Liederer, Bianca M.; Mettetal, Jerome T.; Schroeder, Patricia; Schuck, Edgar; Tsai, Alice; Xu, Christine; Chimalakonda, Anjaneya; Le, Kha; Penney, Mark; Topp, Brian; Yamada, Akihiro

    2018-01-01

    A cross‐industry survey was conducted to assess the landscape of preclinical quantitative systems pharmacology (QSP) modeling within pharmaceutical companies. This article presents the survey results, which provide insights on the current state of preclinical QSP modeling in addition to future opportunities. Our results call attention to the need for an aligned definition and consistent terminology around QSP, yet highlight the broad applicability and benefits preclinical QSP modeling is currently delivering. PMID:29349875

  17. Higher-spin currents in the Gross-Neveu model at 1/n"2

    International Nuclear Information System (INIS)

    Manashov, A.N.

    2016-10-01

    We calculate the anomalous dimensions of higher-spin currents, both singlet and non-singlet, in the Gross - Neveu model at the 1/n"2 order. It was conjectured that in the critical regime this model is dual to a higher-spin gauge theory on AdS_4. The AdS/CFT correspondence predicts that the masses of higher-spin fields correspond to the scaling dimensions of the singlet currents in the Gross - Neveu model.

  18. Small scale currents and ocean wave heights: from today's models to future satellite observations with CFOSAT and SKIM

    Science.gov (United States)

    Ardhuin, Fabrice; Gille, Sarah; Menemenlis, Dimitris; Rocha, Cesar; Rascle, Nicolas; Gula, Jonathan; Chapron, Bertrand

    2017-04-01

    Tidal currents and large oceanic currents, such as the Agulhas, Gulf Stream and Kuroshio, are known to modify ocean wave properties, causing extreme sea states that are a hazard to navigation. Recent advances in the understanding and modeling capability of ocean currents at scales of 10 km or less have revealed the ubiquitous presence of fronts and filaments. Based on realistic numerical models, we show that these structures can be the main source of variability in significant wave heights at scales less than 200 km, including important variations at 10 km. This current-induced variability creates gradients in wave heights that were previously overlooked and are relevant for extreme wave heights and remote sensing. The spectrum of significant wave heights is found to be of the order of 70⟨Hs ⟩2/(g2⟨Tm0,-1⟩2) times the current spectrum, where ⟨Hs ⟩ is the spatially-averaged significant wave height, ⟨Tm0,-1⟩ is the average energy period, and g is the gravity acceleration. This small scale variability is consistent with Jason-3 and SARAL along-track variability. We will discuss how future satellite mission with wave spectrometers can help observe these wave-current interactions. CFOSAT is due for launch in 2018, and SKIM is a proposal for ESA Earth Explorer 9.

  19. Proposal of Constraints Analysis Method Based on Network Model for Task Planning

    Science.gov (United States)

    Tomiyama, Tomoe; Sato, Tatsuhiro; Morita, Toyohisa; Sasaki, Toshiro

    Deregulation has been accelerating several activities toward reengineering business processes, such as railway through service and modal shift in logistics. Making those activities successful, business entities have to regulate new business rules or know-how (we call them ‘constraints’). According to the new constraints, they need to manage business resources such as instruments, materials, workers and so on. In this paper, we propose a constraint analysis method to define constraints for task planning of the new business processes. To visualize each constraint's influence on planning, we propose a network model which represents allocation relations between tasks and resources. The network can also represent task ordering relations and resource grouping relations. The proposed method formalizes the way of defining constraints manually as repeatedly checking the network structure and finding conflicts between constraints. Being applied to crew scheduling problems shows that the method can adequately represent and define constraints of some task planning problems with the following fundamental features, (1) specifying work pattern to some resources, (2) restricting the number of resources for some works, (3) requiring multiple resources for some works, (4) prior allocation of some resources to some works and (5) considering the workload balance between resources.

  20. From representing to modelling knowledge: Proposing a two-step training for excellence in concept mapping

    Directory of Open Access Journals (Sweden)

    Joana G. Aguiar

    2017-09-01

    Full Text Available Training users in the concept mapping technique is critical for ensuring a high-quality concept map in terms of graphical structure and content accuracy. However, assessing excellence in concept mapping through structural and content features is a complex task. This paper proposes a two-step sequential training in concept mapping. The first step requires the fulfilment of low-order cognitive objectives (remember, understand and apply to facilitate novices’ development into good Cmappers by honing their knowledge representation skills. The second step requires the fulfilment of high-order cognitive objectives (analyse, evaluate and create to grow good Cmappers into excellent ones through the development of knowledge modelling skills. Based on Bloom’s revised taxonomy and cognitive load theory, this paper presents theoretical accounts to (1 identify the criteria distinguishing good and excellent concept maps, (2 inform instructional tasks for concept map elaboration and (3 propose a prototype for training users on concept mapping combining online and face-to-face activities. The proposed training application and the institutional certification are the next steps for the mature use of concept maps for educational as well as business purposes.

  1. APC-PC Combined Scheme in Gilbert Two State Model: Proposal and Study

    Science.gov (United States)

    Bulo, Yaka; Saring, Yang; Bhunia, Chandan Tilak

    2017-04-01

    In an automatic repeat request (ARQ) scheme, a packet is retransmitted if it gets corrupted due to transmission errors caused by the channel. However, an erroneous packet may contain both erroneous bits and correct bits and hence it may still contain useful information. The receiver may be able to combine this information from multiple erroneous copies to recover the correct packet. Packet combining (PC) is a simple and elegant scheme of error correction in transmitted packet, in which two received copies are XORed to obtain the bit location of erroneous bits. Thereafter, the packet is corrected by bit inversion of bit located as erroneous. Aggressive packet combining (APC) is a logic extension of PC primarily designed for wireless communication with objective of correcting error with low latency. PC offers higher throughput than APC, but PC does not correct double bit errors if occur in same bit location of erroneous copies of the packet. A hybrid technique is proposed to utilize the advantages of both APC and PC while attempting to remove the limitation of both. In the proposed technique, applications of APC-PC on Gilbert two state model has been studied. The simulation results show that the proposed technique offers better throughput than the conventional APC and lesser packet error rate than PC scheme.

  2. Physics-based electromechanical model of IPMC considering various underlying currents

    Science.gov (United States)

    Pugal, D.; Kim, K. J.; Palmre, V.; Leang, K. K.; Aabloo, A.

    2012-04-01

    Experiments indicate that the electrodes affect the charge dynamics, and therefore actuation of ionic polymermetal composite (IPMC) via three different types of currents - electric potential induced ionic current, leakage current, and electrochemical current if approximately higher than 2 V voltage is applied to a typical 200 μm thick IPMC. The ionic current via charge accumulation near the electrodes is the direct cause of the osmotic and electrostatic stresses in the polymer and therefore carries the major role in the actuation of IPMC. However, the leakage and the electrochemical - electrolysis in case of water based IPMCs - currents do not affect the actuation dynamics as directly but cause potential gradients on the electrodes. These in turn affect the ionic current. A physics based finite element (FE) model was developed to incorporate the effect of the electrodes and three different types of currents in the actuation calculations. The Poisson-Nernst-Planck system of equations is used in the model to describe the ionic current and the Butler-Volmer relation is used to describe the electrolysis current for different applied voltages and IPMC thicknesses. To validate the model, calculated tip deflection, applied net current, and potential drop in case of various IPMC thicknesses and applied voltages are compared to experimental data.

  3. A model proposal concerning balance scorecard application integrated with resource consumption accounting in enterprise performance management

    Directory of Open Access Journals (Sweden)

    ORHAN ELMACI

    2014-06-01

    Full Text Available The present study intended to investigate the “Balance Scorecard (BSC model integrated with Resource Consumption Accounting (RCA” which helps to evaluate the enterprise as matrix structure in its all parts. It aims to measure how much tangible and intangible values (assets of enterprises contribute to the enterprises. In other words, it measures how effectively, actively, and efficiently these values (assets are used. In short, it aims to measure sustainable competency of enterprises. As expressing the effect of tangible and intangible values (assets of the enterprise on the performance in mathematical and statistical methods is insufficient, it is targeted that RCA Method integrated with BSC model is based on matrix structure and control models. The effects of all complex factors in the enterprise on the performance (productivity and efficiency estimated algorithmically with cause and effect diagram. The contributions of matrix structures for reaching the management functional targets of the enterprises that operate in market competitive environment increasing day to day, is discussed. So in the context of modern management theories, as a contribution to BSC approach which is in the foreground in today’s administrative science of enterprises in matrix organizational structures, multidimensional performance evaluation model -RCA integrated with BSC Model proposal- is presented as strategic planning and strategic evaluation instrument.

  4. A Proposed Model for Measuring Performance of the University-Industry Collaboration in Open Innovation

    Directory of Open Access Journals (Sweden)

    Anca Draghici

    2017-06-01

    Full Text Available The paper aims to present a scientific approach to the creation, testing and validation of a model for performance measurement for university-industry collaboration (UIC. The main idea of the design process is to capitalize on existing success factors, facilitators and opportunities (motivation factors, knowledge transfer channels and identified benefits and to diminish or avoid potential threats and barriers that might interfere with such collaborations. The main purpose of the applied methodology is to identify solutions and measures to overcome the disadvantages, conflicts or risk issues and to facilitate the open innovation of industrial companies and universities. The methodology adopted was differentiated by two perspectives: (1 a business model reflecting the university perspective along with an inventory of key performance indicators (KPIs; (2 a performance measurement model (including performance criteria and indicators and an associated methodology (assimilated to an audit that could help companies increase collaboration with universities in the context of open innovation. In addition, in order to operationalize the proposed model (facilitating practical implementation, an Excel tool has been created to help identifying potential sources of innovation. The main contributions of the research concern the expansion of UICs knowledge to enhance open innovation and to define an effective performance measurement model and instrument (tested and validated by a case study for companies.

  5. The proposed 'concordance-statistic for benefit' provided a useful metric when modeling heterogeneous treatment effects.

    Science.gov (United States)

    van Klaveren, David; Steyerberg, Ewout W; Serruys, Patrick W; Kent, David M

    2018-02-01

    Clinical prediction models that support treatment decisions are usually evaluated for their ability to predict the risk of an outcome rather than treatment benefit-the difference between outcome risk with vs. without therapy. We aimed to define performance metrics for a model's ability to predict treatment benefit. We analyzed data of the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) trial and of three recombinant tissue plasminogen activator trials. We assessed alternative prediction models with a conventional risk concordance-statistic (c-statistic) and a novel c-statistic for benefit. We defined observed treatment benefit by the outcomes in pairs of patients matched on predicted benefit but discordant for treatment assignment. The 'c-for-benefit' represents the probability that from two randomly chosen matched patient pairs with unequal observed benefit, the pair with greater observed benefit also has a higher predicted benefit. Compared to a model without treatment interactions, the SYNTAX score II had improved ability to discriminate treatment benefit (c-for-benefit 0.590 vs. 0.552), despite having similar risk discrimination (c-statistic 0.725 vs. 0.719). However, for the simplified stroke-thrombolytic predictive instrument (TPI) vs. the original stroke-TPI, the c-for-benefit (0.584 vs. 0.578) was similar. The proposed methodology has the potential to measure a model's ability to predict treatment benefit not captured with conventional performance metrics. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Toward a new model of scientific publishing: Discussion and a proposal

    Directory of Open Access Journals (Sweden)

    Dwight eKravitz

    2011-12-01

    Full Text Available The current system of publishing in the neurosciences, is notable for its redundancy, inconsistency, sluggishness, and opacity. These problems persist, and grow worse, because of a continuing failure to fully leverage new technology. Online access has eliminated space limits within peer-reviewed journals, yet we continue to deny publication. Each submission of a rejected manuscript requires the entire machinery of peer review to creak to life. This redundancy causes delays, inconsistency, and increases the burden on authors, reviewers, and editors. Further, reviewers serve a key role in the process but their performance is not tracked; yet alone rewarded. This misalignment of incentives contributes to the inconsistency and sluggishness that pervades peer review. The current system also interferes with the primary purpose of modern journals, providing a quick way of prioritizing the literature. Reviews are written to gauge publication rather than scientific merit and there is no guarantee that the journal’s criteria agree with those of an individual researcher, making any prioritization opaque and noisy at best.The focus of this special issue is the future form of post-publication reception, and the development of a marketplace where a paper rises and falls based on its reception from the field. However, the information that accompanies a paper into the marketplace is as important as the marketplace’s mechanics. Beyond suggestions as to the mechanisms of reception, we propose an update to the system of publishing in which publication is guaranteed, but pre-publication peer review still occurs, giving the authors the opportunity to revise their work following a mini pre-reception from the field. This step also provides a consistent set of rankings and reviews to the marketplace, allowing for early prioritization and stabilizing its early dynamics. We further propose to improve the general quality of reviewing by providing tangible rewards to

  7. Proposing a model for limiting earning management practices: The case of Jordanian listed firms

    Directory of Open Access Journals (Sweden)

    Dea’a Al-Deen Al-Sraheen

    2016-11-01

    Full Text Available The key objective of this paper is to propose a model for limiting earning management practices among manufacturing firms in Jordan. In order to do so, two independent variables are examined in this paper, namely, political influence and CEO Duality. Discretionary total accruals according to the modified Jones model (1991 was used in order to estimate the level of earnings management, which is the dependent variable. The sample comprised 64 companies for the financial year 2013. The results suggest that a positive and significant association existed among both political influence and CEO duality and earning management. This means that both independent variables exacerbated earnings management. Further research is required to determine what urgent legislation should be developed to restrict the presence of members who have political connections on the board of directors. Also, the need exists for the separation of roles of Chairman and CEO to ensure the independence and complying with the requirements of corporate governance.

  8. Proposed Model for Integrating RAMS Method in the Design Process in Construction

    Directory of Open Access Journals (Sweden)

    Saad Al-Jibouri

    2010-05-01

    Full Text Available There is a growing trend in the Netherlands for outsourcing public construction activities to the private sector through the use of integrated contracts. There is also an increasing emphasis from public clients on the use of RAMS and life cycle costing (LCC in the design process of infrastructural projects to improve the performance of designed systems and optimize the project cost. RAMS is an acronym for `reliability, availability, maintainability and safety' and represents a collection of techniques to provide predictions of the performance targets of the required system. Increasingly, RAMS targets are being specified in invitation to tender or contract documents and the parties responsible for the design are required to provide evidence of its application in their design. Recent evidence from practice, complemented with a literature study, has shown that the knowledge and application of RAMS in infrastructural designs are in their infancy compared with other industrial sectors and many designers in construction do not have the necessary knowledge and experience to apply it. This paper describes a proposed model for the integration of RAMS and LCC into the design process in construction. A variation of the model for the application of RAMS in `design, build, finance and maintain' (DBFM contracts that include maintenance requirements is also proposed. The two models involve providing guidelines to simplify the application of RAMs by the designers. The model has been validated for its practicality and usefulness during a workshop by experienced designers. DOI: 10.3763/aedm.2008.0100 Published in the Journal AEDM - Volume 5, Number 4, 2009 , pp. 179-192(14

  9. AN EFFECTIVE RISK-PREVENTIVE MODEL PROPOSAL FOR OCCUPATIONAL ACCIDENTS AT SHIPYARDS

    Directory of Open Access Journals (Sweden)

    Ozge Acuner

    2016-03-01

    Full Text Available According to the statistics of occupational accidents, it is observed that the number of accidents occurred in shipbuilding industry is high and the rate of deaths and serious injuries among these accidents is higher than in other industries. However, the number of the studies to prevent these accidents in both industrial and scientific practices is considerably low. Therefore, the objective of this study is to develop an efficient risk preventive model in accordance with occupational health and safety regulations for industrial organizations. The approach proposed in this study differs from those described in the literature, because it is based on fuzzy set theory in order to cope with uncertainties on probability and severity definitions in terms of occupational health and safety. Furthermore, in this paper, risk severity is considered in terms of harm to worker, harm to environment, and harm to hardware, whereas in the literature, risk severity is generally considered solely in terms of only harm to worker. Then, risk magnitude is obtained by utilizing fuzzy inference system. The proposed approach is applied to a shipyard located in the Marmara Region in order to illustrate the applicability of the model.

  10. Proposed retention model for human inhalation exposure to 241AmO2

    International Nuclear Information System (INIS)

    Mewhinney, J.A.; Griffith, W.C.; Muggenburg, B.A.

    1980-01-01

    A dosimetry model based on a four-year study in Beagle dogs was developed to predict patterns of absorbed radiation doses for people exposed by inhalation to 241 AmO 2 . Following a single inhalation exposure to one of three sizes of monodisperse or a polydisperse aerosol of 241 AmO 2 , pairs of dogs were sacrificed at 8, 32, 64 and 256 days, and 2 and 4 years. For about 80% of the initial lung burden, the retention halftimes were 11, 18, 26 and 27 days for the 0.75, 1.5 and 3.0 μm aerodynamic diameter and the 1.8 μm activity median aerodynamic diameter aerosols, respectively. For the remaining 20% of the initial lung burden, the retention halftimes were between 200 to 300 days with no apparent particle size influence. Additional 241 Am metabolic studies reported in the literature using inhalation exposure or injection of the citrate complex were synthesized in the model as were eleven reported cases of human inhalation exposure. This model is compared to the ICRP II and TGLD lung models, both developed by analogy to Pu metabolism. The proposed model differs from these latter models in two important areas: (a) lung retention of 241 AmO 2 could not be adapted to the classifications used in these models, and (b) the fractional translocation from lung to other organs is 2 to 8 times larger. These factors considerably alter the predicted radiation dose distribution among organs and lead to the conclusion that derived radiation protection standards for 241 AmO 2 inhalation exposure should be modified. (author)

  11. Tunneling current between graphene layers

    OpenAIRE

    Poklonski, Nikolai A.; Siahlo, Andrei I.; Vyrko, Sergey A.; Popov, Andrey M.; Lozovik, Yurii E.

    2013-01-01

    The physical model that allows to calculate the values of the tunneling current be-tween graphene layers is proposed. The tunneling current according to the pro-posed model is proportional to the area of tunneling transition. The calculated value of tunneling conductivity is in qualitative agreement with experimental data.

  12. On the scale similarity in large eddy simulation. A proposal of a new model

    International Nuclear Information System (INIS)

    Pasero, E.; Cannata, G.; Gallerano, F.

    2004-01-01

    validity of the proposed model was tested through channel flow simulation with friction-velocity-based Reynolds numbers ranging from 180 to 2340. (author)

  13. Single-layer skull approximations perform well in transcranial direct current stimulation modeling

    NARCIS (Netherlands)

    Rampersad, S.M.; Stegeman, D.F.; Oostendorp, T.F.

    2013-01-01

    In modeling the effect of transcranial direct current stimulation, the representation of the skull is an important factor. In a spherical model, we compared a realistic skull modeling approach, in which the skull consisted of three isotropic layers, to anisotropic and isotropic single-layer

  14. THE MATHEMATIC MODEL OF POTENTIAL RELAXATION IN COULOSTATIC CONDITIONS FOR LIMITING DIFFUSION CURRENT CASE

    Directory of Open Access Journals (Sweden)

    O. H. Kapitonov

    2010-05-01

    Full Text Available A mathematical model of coulostatic relaxation of the potential for solid metallic electrode was presented. The solution in the case of limiting diffusion current was obtained. On the basis of this model the technique of concentration measurements for heavy metal ions in diluted solutions was suggested. The model adequacy was proved by experimental data.

  15. Eddy Current Loss Modeling for Design of PM Generators for Wind Turbines

    NARCIS (Netherlands)

    Jassal, A.

    2014-01-01

    This thesis deals with analysis, calculation and validation of eddy current loss models for Permanent Magnet (PM) direct drive generators for wind turbines. The modelling approach is a mixed use of analytical and Finite Element (FE) methods. The models are validated experimentally and design

  16. Information Systems Success In Public Administration: Proposal For An Exploratory Model

    Directory of Open Access Journals (Sweden)

    Deyvison de Lima Oliveira

    2015-12-01

    Full Text Available Investments in Information Systems (IS have been significantly increasing and hence the relevance of the studies on the IS success is persistent. Delone and Mclean (2003 developed an IS successful model which is a benchmark for researches in the area, however, in the perspective of the public sector, studies are still rare. In this research it was sought to propose an exploratory model of successful IS in public administration, from the identification of each construct items of the Delone and McLean (2003 original model, through multiple case studies in three Municipalities and a Town Hall of the Southern Cone of Rondônia state, in Brazil. Based on the empirical research, it was found that the IS success factors in municipal public administration are close to those factors indicated in the reviewed literature, however, showing some particularities of the public sector. A model of successful factors and items of IS, from the confrontation between literature and empirical data, is presented in the end of this work.

  17. Dynamic neural network modeling of HF radar current maps for forecasting oil spill trajectories

    International Nuclear Information System (INIS)

    Tissot, P.; Perez, J.; Kelly, F.J.; Bonner, J.; Michaud, P.

    2001-01-01

    This paper examined the concept of dynamic neural network (NN) modeling for short-term forecasts of coastal high-frequency (HF) radar current maps offshore of Galveston Texas. HF radar technology is emerging as a viable and affordable way to measure surface currents in real time and the number of users applying the technology is increasing. A 25 megahertz, two site, Seasonde HF radar system was used to map ocean and bay surface currents along the coast of Texas where wind and river discharge create complex and rapidly changing current patters that override the weaker tidal flow component. The HF radar system is particularly useful in this type of setting because its mobility makes it a good marine spill response tool that could provide hourly current maps. This capability helps improve deployment of response resources. In addition, the NN model recently developed by the Conrad Blucher Institute can be used to forecast water levels during storm events. Forecasted currents are based on time series of current vectors from HF radar plus wind speed, wind direction, and water levels, as well as tidal forecasts. The dynamic NN model was tested to evaluate its performance and the results were compared with a baseline model which assumes the currents do not change from the time of the forecast up to the forecasted time. The NN model showed improvements over the baseline model for forecasting time equal or greater than 3 hours, but the difference was relatively small. The test demonstrated the ability of the dynamic NN model to link meteorological forcing functions with HF radar current maps. Development of the dynamic NN modeling is still ongoing. 18 refs., 1 tab., 5 figs

  18. Design of six pulse bridge multiplication converter model for current harmonic elimination of three phase ac-dc converter

    International Nuclear Information System (INIS)

    Soomro, M.A.; Helepoto, I.A.

    2014-01-01

    The recent development of semiconductor technology and wide spread use of power electronic devices in power system have open the era of the power system harmonics due to increasing penetration of non-linear loads. Harmonics are widely admitted as most important issues of power quality which must be eliminated to maintain power system reliability. The tolerable THD (Total Harmonic Distortion) values must be bounded in well-defined limits recognized by IEEE-519 standard. In this work, in order to eliminate the current harmonics produced by non-linear loads, six pulse multiplication converter technique in conjunction with STSSHPE (Single Tuned Shunt Harmonic Passive Filter) is proposed. The proposed model has the capacity of harmonic cancellation of the dominant 3rd order harmonics. Besides that, the 5th and 7th order harmonics are also reduced to a diminishing level. The hardware model has been experimentally tested by PQA (Power Quality Analyzer) and simulation model is designed using MATLAB software. The acquired results have been measured by considering THD values in terms of current and voltage. Furthermore, they have been compared against IEEE-519 performance standards. The prosed model, successfully bounds the total harmonic distortion under defined limits by IEEE-519 standard. (author)

  19. Distinguishing between depression and anxiety: a proposal for an extension of the tripartite model.

    Science.gov (United States)

    den Hollander-Gijsman, M E; de Beurs, E; van der Wee, N J A; van Rood, Y R; Zitman, F G

    2010-05-01

    The aim of the current study was to develop scales that assess symptoms of depression and anxiety and can adequately differentiate between depression and anxiety disorders, and also can distinguish within anxiety disorders. As point of departure, we used the tripartite model of Clark and Watson that discerns three dimensions: negative affect, positive affect and physiological hyperarousal. Analyses were performed on the data of 1449 patients, who completed the Mood and Anxiety Symptoms Questionnaire (MASQ) and the Brief Symptom Inventory (BSI). From this, 1434 patients were assessed with a standardized diagnostic interview. A model with five dimensions was found: depressed mood, lack of positive affect, somatic arousal, phobic fear and hostility. The scales appear capable to differentiate between patients with a mood and with an anxiety disorder. Within the anxiety disorders, somatic arousal was specific for patients with panic disorder. Phobic fear was associated with panic disorder, simple phobia and social anxiety disorder, but not with generalized anxiety disorder. We present a five-factor model as an extension of the tripartite model. Through the addition of phobic fear, anxiety is better represented than in the tripartite model. The new scales are capable to accurately differentiate between depression and anxiety disorders, as well as between several anxiety disorders. (c) 2009 Elsevier Masson SAS. All rights reserved.

  20. Accurate Modelling of Surface Currents and Internal Tides in a Semi-enclosed Coastal Sea

    Science.gov (United States)

    Allen, S. E.; Soontiens, N. K.; Dunn, M. B. H.; Liu, J.; Olson, E.; Halverson, M. J.; Pawlowicz, R.

    2016-02-01

    The Strait of Georgia is a deep (400 m), strongly stratified, semi-enclosed coastal sea on the west coast of North America. We have configured a baroclinic model of the Strait of Georgia and surrounding coastal waters using the NEMO ocean community model. We run daily nowcasts and forecasts and publish our sea-surface results (including storm surge warnings) to the web (salishsea.eos.ubc.ca/storm-surge). Tides in the Strait of Georgia are mixed and large. The baroclinic model and previous barotropic models accurately represent tidal sea-level variations and depth mean currents. The baroclinic model reproduces accurately the diurnal but not the semi-diurnal baroclinic tidal currents. In the Southern Strait of Georgia, strong internal tidal currents at the semi-diurnal frequency are observed. Strong semi-diurnal tides are also produced in the model, but are almost 180 degrees out of phase with the observations. In the model, in the surface, the barotropic and baroclinic tides reinforce, whereas the observations show that at the surface the baroclinic tides oppose the barotropic. As such the surface currents are very poorly modelled. Here we will present evidence of the internal tidal field from observations. We will discuss the generation regions of the tides, the necessary modifications to the model required to correct the phase, the resulting baroclinic tides and the improvements in the surface currents.

  1. Study on possibility of plasma current profile determination using an analytical model of tokamak equilibrium

    International Nuclear Information System (INIS)

    Moriyama, Shin-ichi; Hiraki, Naoji

    1996-01-01

    The possibility of determining the current profile of tokamak plasma from the external magnetic measurements alone is investigated using an analytical model of tokamak equilibrium. The model, which is based on an approximate solution of the Grad-Shafranov equation, can set a plasma current profile expressed with four free parameters of the total plasma current, the poloidal beta, the plasma internal inductance and the axial safety factor. The analysis done with this model indicates that, for a D-shaped plasma, the boundary poloidal magnetic field prescribing the external magnetic field distribution is dependent on the axial safety factor in spite of keeping the boundary safety factor and the plasma internal inductance constant. This suggests that the plasma current profile is reversely determined from the external magnetic analysis. The possibility and the limitation of current profile determination are discussed through this analytical result. (author)

  2. Analysis and Modeling of Circulating Current in Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand

    2015-01-01

    Parallel-connected inverters are gaining attention for high power applications because of the limited power handling capability of the power modules. Moreover, the parallel-connected inverters may have low total harmonic distortion of the ac current if they are operated with the interleaved pulse...... this model, the circulating current between two parallel-connected inverters is analysed in this study. The peak and root mean square (rms) values of the normalised circulating current are calculated for different PWM methods, which makes this analysis a valuable tool to design a filter for the circulating......-width modulation (PWM). However, the interleaved PWM causes a circulating current between the inverters, which in turn causes additional losses. A model describing the dynamics of the circulating current is presented in this study which shows that the circulating current depends on the common-mode voltage. Using...

  3. Two ways to model voltage-current curves of adiabatic MgB2 wires

    International Nuclear Information System (INIS)

    Stenvall, A; Korpela, A; Lehtonen, J; Mikkonen, R

    2007-01-01

    Usually overheating of the sample destroys attempts to measure voltage-current curves of conduction cooled high critical current MgB 2 wires at low temperatures. Typically, when a quench occurs a wire burns out due to massive heat generation and negligible cooling. It has also been suggested that high n values measured with MgB 2 wires and coils are not an intrinsic property of the material but arise due to heating during the voltage-current measurement. In addition, quite recently low n values for MgB 2 wires have been reported. In order to find out the real properties of MgB 2 an efficient computational model is required to simulate the voltage-current measurement. In this paper we go back to basics and consider two models to couple electromagnetic and thermal phenomena. In the first model the magnetization losses are computed according to the critical state model and the flux creep losses are considered separately. In the second model the superconductor resistivity is described by the widely used power law. Then the coupled current diffusion and heat conduction equations are solved with the finite element method. In order to compare the models, example runs are carried out with an adiabatic slab. Both models produce a similar significant temperature rise near the critical current which leads to fictitiously high n values

  4. Harmonic current prediction by impedance modeling of grid-tied inverters

    DEFF Research Database (Denmark)

    Pereira, Heverton A.; Freijedo, Francisco D.; Silva, M. M.

    2017-01-01

    and harmonic voltage profiles. Results reinforce that impedance models can represent with relatively accuracy the harmonic current emitted by the PV plants at the point of common coupling (PCC). Lastly, a stress test is performed to show how a variation in the harmonic voltage phase angle impacts the PV plant...... impedance models when used in harmonic integration studies. It is aimed to estimate the harmonic current contribution as a function of the background harmonic voltages components. Time domain simulations based on detailed and average models are compared with the impedance model developed in frequency domain....... In grids with harmonic voltages, impedance models can predict the current distortion for all active power injection scenarios. Furthermore, measurements in a 1.4 MW PV plant connected in a distributed grid are used to validate the simulation based on impedance models during different power injections...

  5. An integrated model for estimating energy cost of a tidal current turbine farm

    International Nuclear Information System (INIS)

    Li, Ye; Lence, Barbara J.; Calisal, Sander M.

    2011-01-01

    A tidal current turbine is a device for harnessing energy from tidal currents and functions in a manner similar to a wind turbine. A tidal current turbine farm consists of a group of tidal current turbines distributed in a site where high-speed current is available. The accurate prediction of energy cost of a tidal current turbine farm is important to the justification of planning and constructing such a farm. However, the existing approaches used to predict energy cost of tidal current turbine farms oversimplify the hydrodynamic interactions between turbines in energy prediction and oversimplify the operation and maintenance strategies involved in cost estimation as well as related fees. In this paper, we develop a model, which integrates a marine hydrodynamic model with high accuracy for predicting energy output and a comprehensive cost-effective operation and maintenance model for estimating the cost that may be incurred in producing the energy, to predict energy cost from a tidal current turbine farm. This model is expected to be able to simulate more complicated cases and generate more accurate results than existing models. As there is no real tidal current turbine farm, we validate this model with offshore wind studies. Finally, case studies about Vancouver are conducted with a scenario-based analysis. We minimize the energy cost by minimizing the total cost and maximizing the total power output under constraints related to the local conditions (e.g., geological and labor information) and the turbine specifications. The results suggest that tidal current energy is about ready to penetrate the electricity market in some major cities in North America if learning curve for the operational and maintenance is minimum. (author)

  6. Adler-type sum rule, charge symmetry and neutral current in general multi-triplet model

    International Nuclear Information System (INIS)

    Katuya, Mituaki; Baba, Yoshimitsu; Fujii, Kanji

    1975-01-01

    We derive Adler-type sum rule extended to general multi-triplet model. Paying attention to roles of the colour degree of freedom, we discuss the charge symmetry property of the weak charged current and the structure functions for ν(ν - )+N→l(l - )+X, and also the structure of the neutral current. A comment is given on implications in our theory of Koike and Konuma's result on the neutral hadronic current. (auth.)

  7. Shore-based Path Planning for Marine Vehicles Using a Model of Ocean Currents

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop path planning methods that incorporate an approximate model of ocean currents in path planning for a range of autonomous marine vehicles such as surface...

  8. Currents, HF Radio-derived, Monterey Bay, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  9. Ukraine National Energy Current State and Modelling its Long-Term Development

    International Nuclear Information System (INIS)

    Shulzhenko, S.

    2016-01-01

    Structure of Ukrainian energy sector, its current challenges, drivers of its development and possible long-term pathways, and methodological approaches and methods of mathematical modelling of long-term national energy development.(author).

  10. Physical oceanography - Developing end-to-end models of the California Current Large Marine Ecosystem

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this project is to develop spatially discrete end-to-end models of the California Current LME, linking oceanography, biogeochemistry, food web...

  11. SSWL and BWL: finite element models of compressed magnetic field current generators

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, T.J.; Leeman, J.E.

    1976-01-01

    Documentation is presented for two new computer codes modeling the behavior of compressed magnetic field current generators. Code output results for the typical generator configurations are presented and compared to experimental results. (auth)

  12. Current perpendicular to plane giant magnetoresistance and tunneling magnetoresistance treated with unified model

    NARCIS (Netherlands)

    Jonkers, PAE

    2002-01-01

    The conceptual similarity between current perpendicular to plane giant magnetoresistance (CPP-GMR) and tunneling magnetoresistance (TMR) is exploited by utilizing a unified single-particle model accounting for both types of magnetoresistance. By defining structures composed of ferromagnetic,

  13. Dynamics of the exponential integrate-and-fire model with slow currents and adaptation.

    Science.gov (United States)

    Barranca, Victor J; Johnson, Daniel C; Moyher, Jennifer L; Sauppe, Joshua P; Shkarayev, Maxim S; Kovačič, Gregor; Cai, David

    2014-08-01

    In order to properly capture spike-frequency adaptation with a simplified point-neuron model, we study approximations of Hodgkin-Huxley (HH) models including slow currents by exponential integrate-and-fire (EIF) models that incorporate the same types of currents. We optimize the parameters of the EIF models under the external drive consisting of AMPA-type conductance pulses using the current-voltage curves and the van Rossum metric to best capture the subthreshold membrane potential, firing rate, and jump size of the slow current at the neuron's spike times. Our numerical simulations demonstrate that, in addition to these quantities, the approximate EIF-type models faithfully reproduce bifurcation properties of the HH neurons with slow currents, which include spike-frequency adaptation, phase-response curves, critical exponents at the transition between a finite and infinite number of spikes with increasing constant external drive, and bifurcation diagrams of interspike intervals in time-periodically forced models. Dynamics of networks of HH neurons with slow currents can also be approximated by corresponding EIF-type networks, with the approximation being at least statistically accurate over a broad range of Poisson rates of the external drive. For the form of external drive resembling realistic, AMPA-like synaptic conductance response to incoming action potentials, the EIF model affords great savings of computation time as compared with the corresponding HH-type model. Our work shows that the EIF model with additional slow currents is well suited for use in large-scale, point-neuron models in which spike-frequency adaptation is important.

  14. Asymmetry of the Martian Current Sheet in a Multi-fluid MHD Model

    Science.gov (United States)

    Panoncillo, S. G.; Egan, H. L.; Dong, C.; Connerney, J. E. P.; Brain, D. A.; Jakosky, B. M.

    2017-12-01

    The solar wind carries interplanetary magnetic field (IMF) lines toward Mars, where they drape around the planet's conducting ionosphere, creating a current sheet behind the planet where the magnetic field has opposite polarity on either side. In its simplest form, the current sheet is often thought of as symmetric, extending behind the planet along the Mars-Sun line. Observations and model simulations, however, demonstrate that this idealized representation is only an approximation, and the actual scenario is much more complex. The current sheet can have 3D structure, move back and forth, and be situated dawnward or duskward of the Mars-Sun line. In this project, we utilized a library of global plasma model results for Mars consisting of a collection of multi-fluid MHD simulations where solar max/min, sub-solar longitude, and the orbital position of Mars are varied individually. The model includes Martian crustal fields, and was run for identical steady solar wind conditions. This library was created for the purpose of comparing model results to MAVEN data; we looked at the results of this model library to investigate current sheet asymmetries. By altering one variable at a time we were able to measure how these variables influence the location of the current sheet. We found that the current sheet is typically shifted toward the dusk side of the planet, and that modeled asymmetries are especially prevalent during solar min. Previous model studies that lack crustal fields have found that, for a Parker spiral IMF, the current sheet will shift dawnward, while our results typically show the opposite. This could expose certain limitations in the models used, or it could reveal an interaction between the solar wind and the plasma environment of Mars that has not yet been explored. MAVEN data may be compared to the model results to confirm the sense of the modeled asymmetry. These results help us to probe the physics controlling the Martian magnetotail and atmospheric

  15. One kind of atmosphere-ocean three layer model for calculating the velocity of ocean current

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Z; Xi, P

    1979-10-01

    A three-layer atmosphere-ocean model is given in this paper to calcuate the velocity of ocean current, particularly the function of the vertical coordinate, taking into consideratiln (1) the atmospheric effect on the generation of ocean current, (2) a calculated coefficient of the eddy viscosity instead of an assumed one, and (3) the sea which actually varies in depth.

  16. Flavor-singlet axial-vector current in quark model within background field

    International Nuclear Information System (INIS)

    Chen Kun; Yan Mulin

    1993-01-01

    The flavor-singlet axial-vector current is calculated in a quark model within pseudoscalar background-field through the Seeley-DeWitt coefficients. This current is responsible for the quark spin content of proton and is of O(1) in the large-N e expansion

  17. Modelling band-to-band tunneling current in InP-based heterostructure photonic devices

    NARCIS (Netherlands)

    van Engelen, J.P.; Shen, L.; van der Tol, J.J.G.M.; Smit, M.K.; Kockaert, P.; Emplit, P.; Gorza, S.-P.; Massar, S.

    2015-01-01

    Some semiconductor photonic devices show large discontinuities in the band structure. Short tunnel paths caused by this band structure may lead to an excessive tunneling current, especially in highly doped layers. Modelling of this tunnelling current is therefore important when designing photonic

  18. Socio-economic vulnerability to natural hazards - proposal for an indicator-based model

    Science.gov (United States)

    Eidsvig, U.; McLean, A.; Vangelsten, B. V.; Kalsnes, B.; Ciurean, R. L.; Argyroudis, S.; Winter, M.; Corominas, J.; Mavrouli, O. C.; Fotopoulou, S.; Pitilakis, K.; Baills, A.; Malet, J. P.

    2012-04-01

    Vulnerability assessment, with respect to natural hazards, is a complex process that must consider multiple dimensions of vulnerability, including both physical and social factors. Physical vulnerability refers to conditions of physical assets, and may be modeled by the intensity and magnitude of the hazard, the degree of physical protection provided by the natural and built environment, and the physical robustness of the exposed elements. Social vulnerability refers to the underlying factors leading to the inability of people, organizations, and societies to withstand impacts from the natural hazards. Social vulnerability models can be used in combination with physical vulnerability models to estimate both direct losses, i.e. losses that occur during and immediately after the impact, as well as indirect losses, i.e. long-term effects of the event. Direct impact of a landslide typically includes casualties and damages to buildings and infrastructure while indirect losses may e.g. include business closures or limitations in public services. The direct losses are often assessed using physical vulnerability indicators (e.g. construction material, height of buildings), while indirect losses are mainly assessed using social indicators (e.g. economical resources, demographic conditions). Within the EC-FP7 SafeLand research project, an indicator-based method was proposed to assess relative socio-economic vulnerability to landslides. The indicators represent the underlying factors which influence a community's ability to prepare for, deal with, and recover from the damage associated with landslides. The proposed model includes indicators representing demographic, economic and social characteristics as well as indicators representing the degree of preparedness and recovery capacity. Although the model focuses primarily on the indirect losses, it could easily be extended to include more physical indicators which account for the direct losses. Each indicator is individually

  19. A Possible Minimum Toy Model with Negative Differential Capacitance for Self-sustained Current Oscillation

    International Nuclear Information System (INIS)

    Xiong Gang; Sun Zhouzhou; Wang Xiangrong

    2007-01-01

    We generalize a simple model for superlattices to include the effect of differential capacitance. It is shown that the model always has a stable steady-state solution (SSS) if all differential capacitances are positive. On the other hand, when negative differential capacitance is included, the model can have no stable SSS and be in a self-sustained current oscillation behavior. Therefore, we find a possible minimum toy model with both negative differential resistance and negative differential capacitance which can include the phenomena of both self-sustained current oscillation and I-V oscillation of stable SSSs.

  20. A numerical model of ionospheric convection derived from field-aligned current and the corresponding conductivity

    International Nuclear Information System (INIS)

    Blomberg, L.G.; Marklund, G.T.

    1988-03-01

    A numerical model for the calculation of ionospheric convection patterns from given distributions of field-aligned current and ionospheric conductivity is described. The model includes a coupling between the conductivity and the field-aligned current, so that the conductivity peaks in regions of upward current, as usually observed by measurements. The model is very flexible in that the input distributions, the field-aligned current and the conductivity, have been parameterized in a convenient way. From the primary model output, namely the ionospheric electrostatic potential (or convection) in the corotating frame, a number of other quantities can be computed. These include: the potential in a Sun-fixed frame, the distribution of ionospheric (horizontal) current, and the Joule heating in the ionosphere. This model has been used together with input data inferred from satellite measurements to calculate the high-latitude potential distribution prevailing during a particular event. The model potential variation along the satellite orbit was found to be in excellent agreement with the measured electric field. The model has also been used to study some fundamental properties of the electrodynamics of the high-latitude ionosphere. The results of these different applications of the model have been published separately. (With 23 refs.) (authors)

  1. An Overview of the Current State of Women’s Leadership in Higher Education in Saudi Arabia and a Proposal for Future Research Directions

    Directory of Open Access Journals (Sweden)

    Azzah Alsubaie

    2017-10-01

    Full Text Available Despite the predominance of perspectives on women’s leadership, which consistently emphasize the underrepresentation of women in virtually every sphere of political and economic life in countries around the world, very little is known about women’s leadership, especially in higher education, in the Kingdom of Saudi Arabia (KSA. This has resulted in a gap in the literature, since higher education is one area of employment where Saudi women have made progress, and in spite of complex social, religious, cultural and organisational barriers, some have broken through the glass ceiling into higher education leadership. One goal of this paper is to highlight, through a synthesis of existing literature, the current state of women’s higher education leadership in Saudi Arabia. The second goal of this paper is to propose new directions for future research to address the current dearth of empirical work on women’s leadership in higher education in Saudi Arabia. This may be relevant to other regions of the Middle East and elsewhere.

  2. The Neuroanatomical, Neurophysiological and Psychological Basis of Memory: Current Models and Their Origins

    OpenAIRE

    Camina, Eduardo; Güell, Francisco

    2017-01-01

    This review aims to classify and clarify, from a neuroanatomical, neurophysiological, and psychological perspective, different memory models that are currently widespread in the literature as well as to describe their origins. We believe it is important to consider previous developments without which one cannot adequately understand the kinds of models that are now current in the scientific literature. This article intends to provide a comprehensive and rigorous overview for understanding and...

  3. Numerical Modeling of Edge-Localized-Mode Filaments on Divertor Plates Based on Thermoelectric Currents

    International Nuclear Information System (INIS)

    Wingen, A.; Spatschek, K. H.; Evans, T. E.; Lasnier, C. J.

    2010-01-01

    Edge localized modes (ELMs) are qualitatively and quantitatively modeled in tokamaks using current bursts which have been observed in the scrape-off-layer (SOL) during an ELM crash. During the initial phase of an ELM, a heat pulse causes thermoelectric currents. They first flow in short connection length flux tubes which are initially established by error fields or other nonaxisymmetric magnetic perturbations. The currents change the magnetic field topology in such a way that larger areas of short connection length flux tubes emerge. Then currents predominantly flow in short SOL-like flux tubes and scale with the area of the flux tube assuming a constant current density. Quantitative predictions of flux tube patterns for a given current are in excellent agreement with measurements of the heat load and current flow at the DIII-D target plates during an ELM cycle.

  4. A Proposed Model for Assessing Organisational Culture Towards Achieving Business Objectives

    Directory of Open Access Journals (Sweden)

    Hafez Salleh

    2011-09-01

    Full Text Available Most of the traditional business performances measures are based on productivity and process criteria, which mainly focus on method of investment appraisal such as payback method, return on investment (ROI, cost-benefits analysis (CBA, net present value (NPV, internal rate of return (IRR. However, the measurement scales of business performance are not limited to those measures. One element that has strong correlation to the business performances is ‘organisational culture’. Many studies proved that one of the significant criteria for achieving desired business objectives is the right organisational culture within workplace. Basically, the measurement of organisational culture is reflecting on two distinct elements: organisational culture and business objectives. In broader perspective, an organisation is considered effective if it meets its business objectives. This paper aims to present and discuss the preliminary culture model to indicate the culture performance within organisational. The model has been developed through literature review, expert opinion and experience which is anticipated of being able to potentially measure the culture capability of organisations across industries to “successfully achieve business objectives”. The model is composed of six progressive stages of maturity that an organisation can achieve its culture performance. For each maturity stage, the model describes a set of characteristics that must be in place for the company to achieve each stage. The validity of the proposed model will be tested by a few case studies. The idea is to provide managers with a qualitative measurement tools to enable them to identify where culture improvements are required within their organisations and to indicate their readiness for achieving business objectives.

  5. Global model of zenith tropospheric delay proposed based on EOF analysis

    Science.gov (United States)

    Sun, Langlang; Chen, Peng; Wei, Erhu; Li, Qinzheng

    2017-07-01

    Tropospheric delay is one of the main error budgets in Global Navigation Satellite System (GNSS) measurements. Many empirical correction models have been developed to compensate this delay, and models which do not require meteorological parameters have received the most attention. This study established a global troposphere zenith total delay (ZTD) model, called Global Empirical Orthogonal Function Troposphere (GEOFT), based on the empirical orthogonal function (EOF, also known as geographically weighted PCAs) analysis method and the Global Geodetic Observing System (GGOS) Atmosphere data from 2012 to 2015. The results showed that ZTD variation could be well represented by the characteristics of the EOF base function Ek and associated coefficients Pk. Here, E1 mainly signifies the equatorial anomaly; E2 represents north-south asymmetry, and E3 and E4 reflects regional variation. Moreover, P1 mainly reflects annual and semiannual variation components; P2 and P3 mainly contains annual variation components, and P4 displays semiannual variation components. We validated the proposed GEOFT model using tropospheric delay data of GGOS ZTD grid data and the tropospheric product of the International GNSS Service (IGS) over the year 2016. The results showed that GEOFT model has high accuracy with bias and RMS of -0.3 and 3.9 cm, respectively, with respect to the GGOS ZTD data, and of -0.8 and 4.1 cm, respectively, with respect to the global IGS tropospheric product. The accuracy of GEOFT demonstrating that the use of the EOF analysis method to characterize ZTD variation is reasonable.

  6. A proposed centralised distribution model for the South African automotive component industry

    Directory of Open Access Journals (Sweden)

    Micheline J. Naude

    2009-12-01

    Full Text Available Purpose: This article explores the possibility of developing a distribution model, similar to the model developed and implemented by the South African pharmaceutical industry, which could be implemented by automotive component manufacturers for supply to independent retailers. Problem Investigated: The South African automotive components distribution chain is extensive with a number of players of varying sizes, from the larger spares distribution groups to a number of independent retailers. Distributing to the smaller independent retailers is costly for the automotive component manufacturers. Methodology: This study is based on a preliminary study of an explorative nature. Interviews were conducted with a senior staff member from a leading automotive component manufacturer in KwaZulu Natal and nine participants at a senior management level at five of their main customers (aftermarket retailers. Findings: The findings from the empirical study suggest that the aftermarket component industry is mature with the role players well established. The distribution chain to the independent retailer is expensive in terms of transaction and distribution costs for the automotive component manufacturer. A proposed centralised distribution model for supply to independent retailers has been developed which should reduce distribution costs for the automotive component manufacturer in terms of (1 the lowest possible freight rate; (2 timely and controlled delivery; and (3 reduced congestion at the customer's receiving dock. Originality: This research is original in that it explores the possibility of implementing a centralised distribution model for independent retailers in the automotive component industry. Furthermore, there is a dearth of published research on the South African automotive component industry particularly addressing distribution issues. Conclusion: The distribution model as suggested is a practical one and should deliver added value to automotive

  7. MODEL REQUEST FOR PROPOSALS TO PROVIDE ENERGY AND OTHER ATTRIBUTES FROM AN OFFSHORE WIND POWER PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Jeremy Firestone; Dawn Kurtz Crompton

    2011-10-22

    This document provides a model RFP for new generation. The 'base' RFP is for a single-source offshore wind RFP. Required modifications are noted should a state or utility seek multi-source bids (e.g., all renewables or all sources). The model is premised on proposals meeting threshold requirements (e.g., a MW range of generating capacity and a range in terms of years), RFP issuer preferences (e.g., likelihood of commercial operation by a date certain, price certainty, and reduction in congestion), and evaluation criteria, along with a series of plans (e.g., site, environmental effects, construction, community outreach, interconnection, etc.). The Model RFP places the most weight on project risk (45%), followed by project economics (35%), and environmental and social considerations (20%). However, if a multi-source RFP is put forward, the sponsor would need to either add per-MWh technology-specific, life-cycle climate (CO2), environmental and health impact costs to bid prices under the 'Project Economics' category or it should increase the weight given to the 'Environmental and Social Considerations' category.

  8. A proposed model for assessing service quality in small machining and industrial maintenance companies

    Directory of Open Access Journals (Sweden)

    Morvam dos Santos Netto

    2014-11-01

    Full Text Available Machining and industrial maintenance services include repair (corrective maintenance of equipments, activities involving the assembly-disassembly of equipments, fault diagnosis, machining operations, forming operations, welding processes, assembly and test of equipments. This article proposes a model for assessing the quality of services provided by small machining and industrial maintenance companies, since there is a gap in the literature regarding this issue and because the importance of small service companies in socio-economic development of the country. The model is an adaptation of the SERVQUAL instrument and the criteria determining the quality of services are designed according to the service cycle of a typical small machining and industrial maintenance company. In this sense, the Moments of Truth have been considered in the preparation of two separate questionnaires. The first questionnaire contains 24 statements that reflect the expectations of customers, and the second one contains 24 statements that measure perceptions of service performance. An additional item was included in each questionnaire to assess, respectively, the overall expectation about the services and the overall company performance. Therefore, it is a model that considers the interfaces of the client/supplier relationship, the peculiarities of the machining and industrial maintenance service sector and the company size.

  9. A data envelopment analysis based model for proposing safety improvements: a FMEA approach

    International Nuclear Information System (INIS)

    Garcia, Pauli A. de A.; Barbosa Junior, Gilberto V.; Melo, P.F. Frutuoso e

    2005-01-01

    When performing a probabilistic safety assessment, one important step is the identification of the critical or weak points of all systems to be considered. By properly ranking these critical points, improvement recommendations may be proposed, in order to reduce the associated risks. Many tools are available for the identification of critical points, like the Failure Mode and Effect Analysis (FMEA) and the Hazard and Operability Studies (HAZOP). Once the failure modes or deviations are identified, indices associated to the occurrence probabilities, detection potential, and the effects severity, are assigned to them, and so the failure modes or deviations ranking is performed. It is common practice to assign risk priority numbers for this purpose. These numbers are obtained by multiplying the three aforementioned indices, which typically vary from 1 to 10 (natural numbers). Here, the greater the index, the worst the situation. In this paper, a data envelopment analysis (DEA) based model is used to identify the most critical failure modes or deviations and, by means of their respective distances to the boundary, to assess the improvement percentage for each index of each failure mode or deviation. Starting from this identification procedure, the decision maker can more efficiently propose improvement actions, like reliability allocation, detection design, protective barriers, etc. (author)

  10. Effect of Human Model Height and Sex on Induced Current Dosimetry in Household Induction Heater Users

    Science.gov (United States)

    Tarao, Hiroo; Hayashi, Noriyuki; Isaka, Katsuo

    Induced currents in the high-resolution, anatomical human models are numerically calculated by the impedance method. The human models are supposed to be exposed to highly inhomogeneous 20.9 kHz magnetic fields from a household induction heater (IH). In the case of the adult models, the currents ranging from 5 to 19 mA/m2 are induced for between the shoulder and lower abdomen. Meanwhile, in the case of the child models, the currents ranging from 5 to 21 mA/m2 are induced for between the head and abdomen. In particular, the induced currents near the brain tissue are almost the same as those near the abdomen. When the induced currents in the central nervous system tissues are considered, the induced currents in the child model are 2.1 to 6.9 times as large as those in the adult model under the same B-field exposure environment. These results suggest the importance of further investigation intended for a pregnant female who uses the IH as well as for a child (or the IH users of small standing height).

  11. The role of tourism public-private partnerships in regional development: a conceptual model proposal

    Directory of Open Access Journals (Sweden)

    Mário Franco

    Full Text Available Tourism is characterized as being a sector that stands out as one of the business activities with the greatest potential for worldwide expansion, and as an engine for economic growth. If at the national level, the appeal of tourism is significant, on the local level this sector presents itself as an essential tool in regional development, as a means to avoid regional desertification and stagnation, stimulating the potential of more undeveloped regions. In such a competitive sector as tourism, companies should develop synergies and achieve competitive advantage. In this context, public-private partnerships play an important role in regional development. The aim of this paper is to present a theoretical context that combines different concepts and elements to explain and understand the public-private partnership phenomenon in tourism. A conceptual model of the role of public-private partnerships will be proposed in order to contribute to successful regional development.

  12. Cognitive processes and neural basis of language switching: proposal of a new model.

    Science.gov (United States)

    Moritz-Gasser, Sylvie; Duffau, Hugues

    2009-12-09

    Although studies on bilingualism are abundant, cognitive processes and neural foundations of language switching received less attention. The aim of our study is to provide new insights to this still open question: do dedicated region(s) for language switching exist or is this function underlain by a distributed circuit of interconnected brain areas, part of a more general cognitive system? On the basis of recent behavioral, neuroimaging, and brain stimulation studies, we propose an original 'hodological' model of language switching. This process might be subserved by a large-scale cortico-subcortical network, with an executive system (prefrontal cortex, anterior cingulum, caudate nucleus) controlling a more dedicated language subcircuit, which involves postero-temporal areas, supramarginal and angular gyri, Broca's area, and the superior longitudinal fasciculus.

  13. Computational Approaches to Modeling Artificial Emotion -– An overview of the Proposed Solutions

    Directory of Open Access Journals (Sweden)

    Zdzislaw eKOWALCZUK

    2016-04-01

    Full Text Available Cybernetic approach to modeling artificial emotion through the use of different theories of psychology is considered in this paper, presenting a review of twelve proposed solutions: ActAffAct, FLAME, EMA, ParleE, FearNot!, FAtiMA, WASABI, Cathexis, KARO, MAMID, FCM, and xEmotion. The main motivation for this study is founded on the hypothesis that emotions can play a definite utility role of scheduling variables in the construction of intelligent autonomous systems, agents and mobile robots. In this review we also include an innovative and panoptical, comprehensive system, referred to as the Intelligent System of Decision-making (ISD, which has been employed in practical applications of various autonomous units, and which applies as its part the xEmotion, taking into consideration the personal aspects of emotions, affects (short term emotions and mood (principally, long term emotions.

  14. An integrated ethical approach to bioethical decision-making: A proposed model for ministers

    Directory of Open Access Journals (Sweden)

    Magdalena C. de Lange

    2012-10-01

    Full Text Available This article outlined a model for guidance in ‘doing’ bioethics in a Reformed context. The proposed model suggested that in order to arrive at responsible ethical decisions, one must refer to both contextual elements and theory. The theoretical grounding for this model was based on the integration of a deontological and virtue ethics approach, arguing that virtue enables persons to know and desire the right moral ends and motivates them to carry out appropriate action toward achieving these ends. An integrative model opens up the possibility whereby bioethics as a systematic tool provides the individual decision-maker with the critical-reflective skills and justification for the ultimate choice that is lacking in the general decision-making processes. This could lead to clearer thinking and increased confidence in the justification of decisions within the Reformed tradition. The proposed hermeneutical perspective on ethical decision-making represents a shift in views about the nature of knowledge and the process of how we come to know. The key to this hermeneutical approach is to acknowledge the dialectic between the universal and the subjectivity of human relations. Working in specific religious communities, one needs to take cognisance of the fact that knowledge is situated in the context of human relationships in which the interpreter participates when articulating the meaning of bioethical experiences. Another aspect that is anticipated lies in the realisation that people struggling with bioethical dilemmas should not be viewed as isolated individuals, but as members of a broader faith community. ‘n Geïntegreerde etiese benadering tot bioetiese besluitneming: Voorgestelde model vir predikante. Hierdie artikel het ‘n model geskets wat moontlike riglyne aantoon vir die  beoefening  van  bioetiek  binne  ‘n  Gereformeerde  konteks.  Die  voorgestelde  model argumenteer dat verwysing na beide kontekstuele elemente en teorie

  15. [The carrier model of neurology in Hungary: a proposal for the solution until 2020].

    Science.gov (United States)

    Bereczki, Dániel; Csiba, László; Komoly, Sámuel; Vécsei, László; Ajtay, András

    2011-11-30

    Based on our previous survey on the capacities of neurological services and on the predictable changes in the neurologist workforce in Hungary, we present a proposal for the organization of the structure of neurological services in the future. We discuss the diagnostic groups treated by neurologists, the neurological services and their progressive organization. Using the current capacities as baseline, we propose patient groups to be treated by neurologists in the future, and the levels of services. Based on the tendencies seen in the last years we suggest to consider to allocate acute stroke services exclusively to stroke units in neurological departments, and we identify a few other diagnostic groups where neurology should have a larger share in patient care. We define three levels for inpatient care: university departments, regional/county hospitals, city hospitals. Instead of minimum criteria we assign outpatient and inpatient standards that are functional from the economic point of view as well. University departments cover all areas of neurological services, have a function in graduate and postgraduate training, and on a regional basis they participate in professional quality assurance activities at the county and city hospital levels, and would have a more independent role in residency training. As far as patient care is concerned, the task of the regional/county hospitals would be similar to that of university departments - without the exclusively university functions. A general neurological service would be offered at the city hospital level - the representation of all subspecialties of neurology is not required. Neurorehabilitation would be organized at special units of neurological wards at the city hospital level, at independent neurorehabilitation wards in regional/county hospitals, and also as an outpatient service offered at the patients' home. The most significant organizational change would affect the outpatient neurological services. In addition

  16. Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

    OpenAIRE

    M. Bocquet; H. Elbern; H. Eskes; M. Hirtl; R. Žabkar; G. R. Carmichael; J. Flemming; A. Inness; M. Pagowski; J. L. Pérez Camaño; P. E. Saide; R. San Jose; M. Sofiev; J. Vira; A. Baklanov

    2015-01-01

    Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of three-dimensional chemical (including aerosol) concentrations and perform inverse modeling of input variables or model parameters (e.g., emissions). Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. They offer the possibility to assimilate both meteorologica...

  17. An analytical drain current model for symmetric double-gate MOSFETs

    Directory of Open Access Journals (Sweden)

    Fei Yu

    2018-04-01

    Full Text Available An analytical surface-potential-based drain current model of symmetric double-gate (sDG MOSFETs is described as a SPICE compatible model in this paper. The continuous surface and central potentials from the accumulation to the strong inversion regions are solved from the 1-D Poisson’s equation in sDG MOSFETs. Furthermore, the drain current is derived from the charge sheet model as a function of the surface potential. Over a wide range of terminal voltages, doping concentrations, and device geometries, the surface potential calculation scheme and drain current model are verified by solving the 1-D Poisson’s equation based on the least square method and using the Silvaco Atlas simulation results and experimental data, respectively. Such a model can be adopted as a useful platform to develop the circuit simulator and provide the clear understanding of sDG MOSFET device physics.

  18. An analytical drain current model for symmetric double-gate MOSFETs

    Science.gov (United States)

    Yu, Fei; Huang, Gongyi; Lin, Wei; Xu, Chuanzhong

    2018-04-01

    An analytical surface-potential-based drain current model of symmetric double-gate (sDG) MOSFETs is described as a SPICE compatible model in this paper. The continuous surface and central potentials from the accumulation to the strong inversion regions are solved from the 1-D Poisson's equation in sDG MOSFETs. Furthermore, the drain current is derived from the charge sheet model as a function of the surface potential. Over a wide range of terminal voltages, doping concentrations, and device geometries, the surface potential calculation scheme and drain current model are verified by solving the 1-D Poisson's equation based on the least square method and using the Silvaco Atlas simulation results and experimental data, respectively. Such a model can be adopted as a useful platform to develop the circuit simulator and provide the clear understanding of sDG MOSFET device physics.

  19. Ion current prediction model considering columnar recombination in alpha radioactivity measurement using ionized air transportation

    International Nuclear Information System (INIS)

    Naito, Susumu; Hirata, Yosuke; Izumi, Mikio; Sano, Akira; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi

    2007-01-01

    We present a reinforced ion current prediction model in alpha radioactivity measurement using ionized air transportation. Although our previous model explained the qualitative trend of the measured ion current values, the absolute values of the theoretical curves were about two times as large as the measured values. In order to accurately predict the measured values, we reinforced our model by considering columnar recombination and turbulent diffusion, which affects columnar recombination. Our new model explained the considerable ion loss in the early stage of ion diffusion and narrowed the gap between the theoretical and measured values. The model also predicted suppression of ion loss due to columnar recombination by spraying a high-speed air flow near a contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, we quantitatively clarified the theoretical relation between alpha radioactivity and ion current in laminar flow and turbulent pipe flow. (author)

  20. Charged-current inclusive neutrino cross sections in the SuperScaling model

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, M. V., E-mail: martin.inrne@gmail.com [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Megias, G. D.; Caballero, J. A. [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41080 Sevilla (Spain); González-Jiménez, R. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Moreno, O.; Donnelly, T. W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Barbaro, M. B. [Dipartimento di Fisica, Università di Torino and INFN, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Moya de Guerra, E.; Udías, J. M. [Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain)

    2016-03-25

    SuperScaling model (SuSA) predictions to neutrino-induced charged-current π{sup +} production in the Δ-resonance region are explored under MiniBooNE experimental conditions. The SuSA charged-current π{sup +} results are in good agreement with data on neutrino flux-averaged double-differential cross sections. The SuSA model for quasielastic scattering and its extension to the pion production region are used for predictions of charged-current inclusive neutrino-nucleus cross sections. Results are also compared with the T2K experimental data for inclusive scattering.

  1. An investigation of r.f. travelling wave current drive using the model

    International Nuclear Information System (INIS)

    Bertram, W.K.

    1988-01-01

    Previous experimental investigations in the use of travelling r.f. waves to drive steady toroidal currents in a toroidal plasma have shown that I t , the amount of current driven, is strongly dependent on the ratio of the static toroidal magnetic field B z , to the strength of the r.f. magnetic field B ω . This dependence is characterised by an initial increase and subsequent decrease of I t when B t /B ω increases. It is shown that this observed behaviour is entirely consistent with the behaviour predicted by the current drive model. Results from numerical computations using the model show good quantitative agreement with the published experimental results

  2. The error analysis of the reverse saturation current of the diode in the modeling of photovoltaic modules

    International Nuclear Information System (INIS)

    Wang, Gang; Zhao, Ke; Qiu, Tian; Yang, Xinsheng; Zhang, Yong; Zhao, Yong

    2016-01-01

    In the modeling and simulation of photovoltaic modules, especially in calculating the reverse saturation current of the diode, the series and parallel resistances are often neglected, causing certain errors. We analyzed the errors at the open circuit point, and proposed an iterative algorithm to calculate the modified values of the reverse saturation current, series resistance and parallel resistance of the diode, in order to reduce the errors. Assuming independent irradiation and temperature effects, the irradiation-dependence and the temperature-dependence of the open circuit voltage were introduced to obtain the modified formula of the open circuit voltage under any condition. Experimental results show that this modified formula has high accuracy, even at irradiance as low as 40 W/m"2. The errors of open circuit voltage were significantly reduced, indicating that this modified model is suitable for simulations of photovoltaic modules. - Highlights: • We propose a new method for modeling PV modules with higher accuracy. • The errors of open circuit voltage are significantly reduced. • I_o under any condition is calculated.

  3. A numerical model of ionospheric convection derived from field-aligned currents and the corresponding conductivity

    International Nuclear Information System (INIS)

    Blomberg, L.G.; Marklund, G.T.

    1991-08-01

    A numerical model for the calculation of ionospheric convection patterns from given distributions of field-aligned current and ionospheric conductivity is described. The model includes a coupling between the conductivity and the field-aligned current, so that the conductivity peaks in regions of upward current, as is usually observed by measurements. The model is very flexible in that the input distributions, the field-aligned current and the conductivity, have been parametrized in a convenient way. From the primary model output, namely the ionospheric electrostatic potential (or convection) in the corotating frame, a number of other quantities can be computed. These include; the potential in the inertial frame (the transformation takes into account the non-alignment of the Earths magnetic and geographic axes), the potential in the magnetospheric equatorial plane (projected using either a dipole magnetic field model or the Tsyganenko-Usmanov model, and the assumption of either vanishing parallel electric field or a proportionality between parallel potential and upward field-aligned current), the distribution of ionospheric (horizontal) current, and the Joule heating in the ionosphere. This model has been used together with a new snapshot technique to calculate the high-latitude potential distribution prevailing during a particular event by combining information from global auroral images and local measurements of fields and particles. The model potential variation along the satellite orbit was found to be in excellent agreement with that calculated from the measured electric field. The model has also been used to study some fundamental properties of the electrodynamics of the high-latitude ionosphere. The results of these different applications of the model have been published separately. (au) (39 refs.)

  4. Modelling of Leakage Current Through Double Dielectric Gate Stack in Metal Oxide Semiconductor Capacitor

    International Nuclear Information System (INIS)

    Fatimah A Noor; Mikrajuddin Abdullah; Sukirno; Khairurrijal

    2008-01-01

    In this paper, we have derived analytical expression of leakage current through double barriers in Metal Oxide Semiconductor (MOS) capacitor. Initially, electron transmittance through the MOS capacitor was derived by including the coupling between the transverse and longitudinal energies. The transmittance was then employed to obtain leakage current through the double barrier. In this model, we observed the effect of electron velocity due to the coupling effect and the oxide thickness to the leakage current. The calculated results showed that the leakage current decreases as the electron velocity increases. (author)

  5. [Acute kidney injury after pediatric cardiac surgery: risk factors and outcomes. Proposal for a predictive model].

    Science.gov (United States)

    Cardoso, Bárbara; Laranjo, Sérgio; Gomes, Inês; Freitas, Isabel; Trigo, Conceição; Fragata, Isabel; Fragata, José; Pinto, Fátima

    2016-02-01

    To characterize the epidemiology and risk factors for acute kidney injury (AKI) after pediatric cardiac surgery in our center, to determine its association with poor short-term outcomes, and to develop a logistic regression model that will predict the risk of AKI for the study population. This single-center, retrospective study included consecutive pediatric patients with congenital heart disease who underwent cardiac surgery between January 2010 and December 2012. Exclusion criteria were a history of renal disease, dialysis or renal transplantation. Of the 325 patients included, median age three years (1 day-18 years), AKI occurred in 40 (12.3%) on the first postoperative day. Overall mortality was 13 (4%), nine of whom were in the AKI group. AKI was significantly associated with length of intensive care unit stay, length of mechanical ventilation and in-hospital death (p<0.01). Patients' age and postoperative serum creatinine, blood urea nitrogen and lactate levels were included in the logistic regression model as predictor variables. The model accurately predicted AKI in this population, with a maximum combined sensitivity of 82.1% and specificity of 75.4%. AKI is common and is associated with poor short-term outcomes in this setting. Younger age and higher postoperative serum creatinine, blood urea nitrogen and lactate levels were powerful predictors of renal injury in this population. The proposed model could be a useful tool for risk stratification of these patients. Copyright © 2015 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  6. B220 analysis with the local lymph node assay: proposal for a more flexible prediction model.

    Science.gov (United States)

    Betts, Catherine J; Dearman, Rebecca J; Kimber, Ian; Ryan, Cindy A; Gerberick, G Frank; Lalko, Jon; Api, Anne Marie

    2007-01-01

    The mouse local lymph node assay (LLNA) has been developed and validated for the identification of chemicals that have the potential to induce skin sensitisation. In common with other predictive test methods the accuracy of the LLNA is not absolute and experience has revealed that a few chemicals, including for instance a minority of skin irritants, may elicit false-positive reactions in the assay. To improve further the performance of the LLNA, and to eliminate or reduce false-positives, there has been interest in an adjunct method in which the ability of chemicals to cause increases in the frequency of B220(+) lymphocytes in skin-draining lymph nodes is measured. Previous studies suggest that the use of B220 analyses aligned with the standard LLNA may serve to distinguish further between contact allergens and skin irritants. In the original predictive model, chemicals were regarded as being skin sensitisers if they were able to induce a 1.25-fold or greater increase in the percentage of B220(+) cells within lymph nodes compared with concurrent vehicle controls. Although this first prediction model has proven useful, in the light of more recent experience, and specifically as a consequence of some variability observed in the frequency of B220(+) lymphocytes in nodes taken from vehicle control-treated animals, it is timely now to reconsider and refine the model. As a result a new prediction model is proposed in which reliance on the use of absolute thresholds is reduced, and in which small changes in control values can be better accommodated. (c) 2007 John Wiley & Sons, Ltd.

  7. Transient interaction model of electromagnetic field generated by lightning current pulses and human body

    International Nuclear Information System (INIS)

    Iváncsy, T; Kiss, I; Tamus, Z Á; Szücs, L

    2015-01-01

    The lightning current generates time-varying magnetic field near the down-conductor and the down-conductors are mounted on the wall of the buildings where residential places might be situated. It is well known that the rapidly changing magnetic fields can generate dangerous eddy currents in the human body.The higher duration and gradient of the magnetic field can cause potentially life threatening cardiac stimulation. The coupling mechanism between the electromagnetic field and the human body is based on a well-known physical phenomena (e.g. Faradays law of induction). However, the calculation of the induced current is very complicated because the shape of the organs is complex and the determination of the material properties of living tissues is difficult, as well. Our previous study revealed that the cardiac stimulation is independent of the rising time of the lightning current and only the peak of the current counts.In this study, the authors introduce an improved model of the interaction of electromagnetic fields of lighting current near down-conductor and human body. Our previous models are based on the quasi stationer field calculations, the new improved model is a transient model. This is because the magnetic field around the down-conductor and in the human body can be determined more precisely, therefore the dangerous currents in the body can be estimated. (paper)

  8. A study on the influence of corona on currents and electromagnetic fields predicted by a nonlinear lightning return-stroke model

    Science.gov (United States)

    De Conti, Alberto; Silveira, Fernando H.; Visacro, Silvério

    2014-05-01

    This paper investigates the influence of corona on currents and electromagnetic fields predicted by a return-stroke model that represents the lightning channel as a nonuniform transmission line with time-varying (nonlinear) resistance. The corona model used in this paper allows the calculation of corona currents as a function of the radial electric field in the vicinity of the channel. A parametric study is presented to investigate the influence of corona parameters, such as the breakdown electric field and the critical electric field for the stable propagation of streamers, on predicted currents and electromagnetic fields. The results show that, regardless of the assumed corona parameters, the incorporation of corona into the nonuniform and nonlinear transmission line model under investigation modifies the model predictions so that they consistently reproduce most of the typical features of experimentally observed lightning electromagnetic fields and return-stroke speed profiles. In particular, it is shown that the proposed model leads to close vertical electric fields presenting waveforms, amplitudes, and decay with distance in good agreement with dart leader electric field changes measured in triggered lightning experiments. A comparison with popular engineering return-stroke models further confirms the model's ability to predict consistent electric field waveforms in the close vicinity of the channel. Some differences observed in the field amplitudes calculated with the different models can be related to the fact that current distortion, while present in the proposed model, is ultimately neglected in the considered engineering return-stroke models.

  9. Method of controlling illumination device based on current-voltage model

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an illumination device comprising a number of LEDs, means for receiving an input signal, means for generating an activation signal for at least one of the LEDs based on the input signal. The illumination device comprises further means for obtaining the voltage...... and the colorimetric properties of said light emitted by LED. The present invention relates also to a method of controlling and a meted of calibrating such illumination device....... across and current through the LED and the means for generating the activation signal is adapted to generate the activating signal based on the voltage, the current and a current- voltage model related to LED. The current-voltage model defines a relationship between the current, the voltage...

  10. Computational electromagnetics and model-based inversion a modern paradigm for eddy-current nondestructive evaluation

    CERN Document Server

    Sabbagh, Harold A; Sabbagh, Elias H; Aldrin, John C; Knopp, Jeremy S

    2013-01-01

    Computational Electromagnetics and Model-Based Inversion: A Modern Paradigm for Eddy Current Nondestructive Evaluation describes the natural marriage of the computer to eddy-current NDE. Three distinct topics are emphasized in the book: (a) fundamental mathematical principles of volume-integral equations as a subset of computational electromagnetics, (b) mathematical algorithms applied to signal-processing and inverse scattering problems, and (c) applications of these two topics to problems in which real and model data are used. By showing how mathematics and the computer can solve problems more effectively than current analog practices, this book defines the modern technology of eddy-current NDE. This book will be useful to advanced students and practitioners in the fields of computational electromagnetics, electromagnetic inverse-scattering theory, nondestructive evaluation, materials evaluation and biomedical imaging. Users of eddy-current NDE technology in industries as varied as nuclear power, aerospace,...

  11. Applying computer modeling to eddy current signal analysis for steam generator and heat exchanger tube inspections

    International Nuclear Information System (INIS)

    Sullivan, S.P.; Cecco, V.S.; Carter, J.R.; Spanner, M.; McElvanney, M.; Krause, T.W.; Tkaczyk, R.

    2000-01-01

    Licensing requirements for eddy current inspections for nuclear steam generators and heat exchangers are becoming increasingly stringent. The traditional industry-standard method of comparing inspection signals with flaw signals from simple in-line calibration standards is proving to be inadequate. A more complete understanding of eddy current and magnetic field interactions with flaws and other anomalies is required for the industry to generate consistently reliable inspections. Computer modeling is a valuable tool in improving the reliability of eddy current signal analysis. Results from computer modeling are helping inspectors to properly discriminate between real flaw signals and false calls, and improving reliability in flaw sizing. This presentation will discuss complementary eddy current computer modeling techniques such as the Finite Element Method (FEM), Volume Integral Method (VIM), Layer Approximation and other analytic methods. Each of these methods have advantages and limitations. An extension of the Layer Approximation to model eddy current probe responses to ferromagnetic materials will also be presented. Finally examples will be discussed demonstrating how some significant eddy current signal analysis problems have been resolved using appropriate electromagnetic computer modeling tools

  12. Nuclear Power Plant Life Management - Challenges and Proposal for a Unified Model Integrating Safety and Economics

    International Nuclear Information System (INIS)

    Contri, Paolo; Elsing, Bernhard

    2011-01-01

    In recent years many electric utilities and nuclear power plants adopted policies for improved coordination of both safety and non-safety programs, called plant life management (PLIM), also in view on plant life extension programs, but mainly for an optimisation of operating costs. The implementation of PLIM programs has followed many different approaches, being intrinsically dependent on the national regulatory framework and technical traditions. In Countries with some experience, the PLIM program proved very convenient, especially when coupled with Maintenance, Surveillance an Inspection (MS and I) optimization: average savings are reported in the range of 20-30% of total (maintenance) costs. A unified European model for PLIM was developed at the JRC-Institute for Energy with the support of a network of stakeholders (SENUF), and validated at some EU nuclear plants. This paper provides a summary of the model features, the result of its validation at some plants and summarises the perceived scientific/technological challenges on which JRC proposes to focus, based upon its competencies and skills, having in mind both the European and world-wide context and its potential evolution. (author)

  13. A proposal of ecologic taxes based on thermo-economic performance of heat engine models

    International Nuclear Information System (INIS)

    Barranco-Jimenez, M. A.; Ramos-Gayosso, I.; Rosales, M. A.; Angulo-Brown, F.

    2009-01-01

    Within the context of Finite-Time Thermodynamics (FTT) a simplified thermal power plant model (the so-called Novikov engine) is analyzed under economical criteria by means of the concepts of profit function and the costs involved in the performance of the power plant. In this study, two different heat transfer laws are used, the so called Newton's law of cooling and the Dulong-Petit's law of cooling. Two FTT optimization criteria for the performance analysis are used: the maximum power regime (MP) and the so-called ecological criterion. This last criterion leads the engine model towards a mode of performance that appreciably diminishes the engine's wasted energy. In this work, it is shown that the energy-unit price produced under maximum power conditions is cheaper than that produced under maximum ecological (ME) conditions. This was accomplished by using a typical definition of profits function stemming from economics. The MP-regime produces considerably more wasted energy toward the environment, thus the MP energy-unit price is subsidized by nature. Due to this fact, an ecological tax is proposed, which could be a certain function of the price difference between the MP and ME modes of power production. (author)

  14. Proposal of a model for sales and operations planning (S&OP maturity evaluation

    Directory of Open Access Journals (Sweden)

    Carolina Belotti Pedroso

    2017-11-01

    Full Text Available Abstract A successful S&OP implementation can bring many benefits to organizations, and after its implementation, the S&OP process can evolve and reach higher levels of maturity. Considering that, only through a measurement system, goals and benefits can be achieved, thus, it is essential to assess S&OP maturity level. Many papers on literature adopt a quantitative perspective on S&OP, but just few of them deal with uncertainty present in S&OP decision-making, such as maturity model assessment process that carries subjectivity and uncertainty. Thus, this study proposes a decision making model based on fuzzy theory to evaluate and to categorize S&OP maturity levels and to suggest strategies to increase S&OP maturity. A pilot application was conducted in two manufacturing organizations that have implemented the S&OP process. The results, according to the performance presented, suggest different actions must be taken in terms of ensuring enablers to S&OP implementation.

  15. A Proposal of Ecologic Taxes Based on Thermo-Economic Performance of Heat Engine Models

    Directory of Open Access Journals (Sweden)

    Fernando Angulo-Brown

    2009-11-01

    Full Text Available Within the context of Finite-Time Thermodynamics (FTT a simplified thermal power plant model (the so-called Novikov engine is analyzed under economical criteria by means of the concepts of profit function and the costs involved in the performance of the power plant. In this study, two different heat transfer laws are used, the so called Newton’s law of cooling and the Dulong-Petit’s law of cooling. Two FTT optimization criteria for the performance analysis are used: the maximum power regime (MP and the so-called ecological criterion. This last criterion leads the engine model towards a mode of performance that appreciably diminishes the engine’s wasted energy. In this work, it is shown that the energy-unit price produced under maximum power conditions is cheaper than that produced under maximum ecological (ME conditions. This was accomplished by using a typical definition of profits function stemming from economics. The MP-regime produces considerably more wasted energy toward the environment, thus the MP energy-unit price is subsidized by nature. Due to this fact, an ecological tax is proposed, which could be a certain function of the price difference between the MP and ME modes of power production.

  16. A proposed model of factors influencing hydrogen fuel cell vehicle acceptance

    Science.gov (United States)

    Imanina, N. H. Noor; Kwe Lu, Tan; Fadhilah, A. R.

    2016-03-01

    Issues such as environmental problem and energy insecurity keep worsening as a result of energy use from household to huge industries including automotive industry. Recently, a new type of zero emission vehicle, hydrogen fuel cell vehicle (HFCV) has received attention. Although there are argues on the feasibility of hydrogen as the future fuel, there is another important issue, which is the acceptance of HFCV. The study of technology acceptance in the early stage is a vital key for a successful introduction and penetration of a technology. This paper proposes a model of factors influencing green vehicle acceptance, specifically HFCV. This model is built base on two technology acceptance theories and other empirical studies of vehicle acceptance. It aims to provide a base for finding the key factors influencing new sustainable energy fuelled vehicle, HFCV acceptance which is achieved by explaining intention to accept HFCV. Intention is influenced by attitude, subjective norm and perceived behavioural control from Theory of Planned Behaviour and personal norm from Norm Activation Theory. In the framework, attitude is influenced by perceptions of benefits and risks, and social trust. Perceived behavioural control is influenced by government interventions. Personal norm is influenced by outcome efficacy and problem awareness.

  17. A proposal of ecologic taxes based on thermo-economic performance of heat engine models

    Energy Technology Data Exchange (ETDEWEB)

    Barranco-Jimenez, M. A. [Departamento de Ciencias Basicas, Escuela Superior de Computo del IPN, Av. Miguel Bernal Esq. Juan de Dios Batiz U.P. Zacatenco CP 07738, D.F. (Mexico); Ramos-Gayosso, I. [Unidad de Administracion de Riesgos, Banco de Mexico, 5 de Mayo, Centro, D.F. (Mexico); Rosales, M. A. [Departamento de Fisica y Matematicas, Universidad de las Americas, Puebla Exhacienda Sta. Catarina Martir, Cholula 72820, Puebla (Mexico); Angulo-Brown, F. [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del IPN, Edif. 9 U.P. Zacatenco CP 07738, D.F. (Mexico)

    2009-07-01

    Within the context of Finite-Time Thermodynamics (FTT) a simplified thermal power plant model (the so-called Novikov engine) is analyzed under economical criteria by means of the concepts of profit function and the costs involved in the performance of the power plant. In this study, two different heat transfer laws are used, the so called Newton's law of cooling and the Dulong-Petit's law of cooling. Two FTT optimization criteria for the performance analysis are used: the maximum power regime (MP) and the so-called ecological criterion. This last criterion leads the engine model towards a mode of performance that appreciably diminishes the engine's wasted energy. In this work, it is shown that the energy-unit price produced under maximum power conditions is cheaper than that produced under maximum ecological (ME) conditions. This was accomplished by using a typical definition of profits function stemming from economics. The MP-regime produces considerably more wasted energy toward the environment, thus the MP energy-unit price is subsidized by nature. Due to this fact, an ecological tax is proposed, which could be a certain function of the price difference between the MP and ME modes of power production. (author)

  18. Proposal for a New Model for Highway Records in the Republic of Croatia

    Directory of Open Access Journals (Sweden)

    Rinaldo Paar

    2012-05-01

    Full Text Available Highways are public roads, whose function is to integrate Croatia in the European transport system, link the regions of Croatia and facilitate transit traffic. They are public property for general use, owned by the Republic of Croatia, and they cannot be the subject of acquisition or other proprietary rights of any kind. Today, there are two types of highway record-keeping. The first is conducted by leading companies authorised to manage highways in order to develop a highway database, or create a highway register. The second is conducted by land-management systems; the Cadastre and Land Registry. They are the official public registers for keeping records of land plots, buildings and other structures, and their ownership. Procedures that need to be implemented in the second type of record-keeping often get "stuck" in practice. Based on the problems identified in this model and an analysis of the state of record-keeping, a proposal for a new model for highway records in the Cadastre and Land Registry is given. Keywords: highways; building plot; expropriation; record; Cadastre; Land Registry

  19. 3-D direct current resistivity anisotropic modelling by goal-oriented adaptive finite element methods

    Science.gov (United States)

    Ren, Zhengyong; Qiu, Lewen; Tang, Jingtian; Wu, Xiaoping; Xiao, Xiao; Zhou, Zilong

    2018-01-01

    Although accurate numerical solvers for 3-D direct current (DC) isotropic resistivity models are current available even for complicated models with topography, reliable numerical solvers for the anisotropic case are still an open question. This study aims to develop a novel and optimal numerical solver for accurately calculating the DC potentials for complicated models with arbitrary anisotropic conductivity structures in the Earth. First, a secondary potential boundary value problem is derived by considering the topography and the anisotropic conductivity. Then, two a posteriori error estimators with one using the gradient-recovery technique and one measuring the discontinuity of the normal component of current density are developed for the anisotropic cases. Combing the goal-oriented and non-goal-oriented mesh refinements and these two error estimators, four different solving strategies are developed for complicated DC anisotropic forward modelling problems. A synthetic anisotropic two-layer model with analytic solutions verified the accuracy of our algorithms. A half-space model with a buried anisotropic cube and a mountain-valley model are adopted to test the convergence rates of these four solving strategies. We found that the error estimator based on the discontinuity of current density shows better performance than the gradient-recovery based a posteriori error estimator for anisotropic models with conductivity contrasts. Both error estimators working together with goal-oriented concepts can offer optimal mesh density distributions and highly accurate solutions.

  20. Short-channel drain current model for asymmetric heavily/lightly ...

    Indian Academy of Sciences (India)

    The paper presents a drain current model for double gate metal oxide semiconductor field effect transistors (DG MOSFETs) based on a new velocity saturation model that accounts for short-channel velocity saturation effect independently in the front and the back gate controlled channels under asymmetric front and back ...