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Sample records for allostery limit performance

  1. Engineering allostery.

    Science.gov (United States)

    Raman, Srivatsan; Taylor, Noah; Genuth, Naomi; Fields, Stanley; Church, George M

    2014-12-01

    Allosteric proteins have great potential in synthetic biology, but our limited understanding of the molecular underpinnings of allostery has hindered the development of designer molecules, including transcription factors with new DNA-binding or ligand-binding specificities that respond appropriately to inducers. Such allosteric proteins could function as novel switches in complex circuits, metabolite sensors, or as orthogonal regulators for independent, inducible control of multiple genes. Advances in DNA synthesis and next-generation sequencing technologies have enabled the assessment of millions of mutants in a single experiment, providing new opportunities to study allostery. Using the classic LacI protein as an example, we describe a genetic selection system using a bidirectional reporter to capture mutants in both allosteric states, allowing the positions most crucial for allostery to be identified. This approach is not limited to bacterial transcription factors, and could reveal new mechanistic insights and facilitate engineering of other major classes of allosteric proteins such as nuclear receptors, two-component systems, G protein-coupled receptors, and protein kinases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. A footnote on allostery.

    Science.gov (United States)

    Crick, F H C; Wyman, Jeffries

    2013-05-13

    A manuscript on allostery signed by Francis Crick and Jeffries Wyman was sent by Crick to Jacques Monod in 1965. Monod transmitted a copy of the manuscript, upon which he had written several comments, to Jean-Pierre Changeux, then a post-doctoral fellow at the University of California Berkeley in the laboratory of Howard Schachman. Changeux provided a copy to Stuart Edelstein, a graduate student in the same laboratory. The manuscript was never submitted for publication, but Edelstein retained his copy since that time and has edited it for publication in the special issue on allostery. The text emphasized the interpretation of the properties of an allosteric oligomer by characterizing its equivalent monomer. The text also developed the concept of the allosteric range and included a simple equation for calculation of the Hill coefficient from the parameters of the Monod-Wyman-Changeux model. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Limitations on blanket performance

    International Nuclear Information System (INIS)

    Malang, S.

    1999-01-01

    The limitations on the performance of breeding blankets in a fusion power plant are evaluated. The breeding blankets will be key components of a plant and their limitations with regard to power density, thermal efficiency and lifetime could determine to a large degree the attractiveness of a power plant. The performance of two rather well known blanket concepts under development in the frame of the European Blanket Programme is assessed and their limitations are compared with more advanced (and more speculative) concepts. An important issue is the question of which material (structure, breeder, multiplier, coatings) will limit the performance and what improvement would be possible with a 'better' structural material. This evaluation is based on the premise that the performance of the power plant will be limited by the blankets (including first wall) and not by other components, e.g. divertors, or the plasma itself. However, the justness of this premise remains to be seen. It is shown that the different blanket concepts cover a large range of allowable power densities and achievable thermal efficiencies, and it is concluded that there is a high incentive to go for better performance in spite of possibly higher blanket cost. However, such high performance blankets are usually based on materials and technologies not yet developed and there is a rather high risk that the development could fail. Therefore, it is explained that a part of the development effort should be devoted to concepts where the materials and technologies are more or less in hand in order to ensure that blankets for a DEMO reactor can be developed and tested in a given time frame. (orig.)

  4. A unified view of "how allostery works".

    Science.gov (United States)

    Tsai, Chung-Jung; Nussinov, Ruth

    2014-02-01

    The question of how allostery works was posed almost 50 years ago. Since then it has been the focus of much effort. This is for two reasons: first, the intellectual curiosity of basic science and the desire to understand fundamental phenomena, and second, its vast practical importance. Allostery is at play in all processes in the living cell, and increasingly in drug discovery. Many models have been successfully formulated, and are able to describe allostery even in the absence of a detailed structural mechanism. However, conceptual schemes designed to qualitatively explain allosteric mechanisms usually lack a quantitative mathematical model, and are unable to link its thermodynamic and structural foundations. This hampers insight into oncogenic mutations in cancer progression and biased agonists' actions. Here, we describe how allostery works from three different standpoints: thermodynamics, free energy landscape of population shift, and structure; all with exactly the same allosteric descriptors. This results in a unified view which not only clarifies the elusive allosteric mechanism but also provides structural grasp of agonist-mediated signaling pathways, and guides allosteric drug discovery. Of note, the unified view reasons that allosteric coupling (or communication) does not determine the allosteric efficacy; however, a communication channel is what makes potential binding sites allosteric.

  5. Performance limitations at ISABELLE

    International Nuclear Information System (INIS)

    Keil, E.

    1975-01-01

    The transverse stability of coasting beams in the planned ISABELLE storage rings was studied. The beam--beam tune shift limitation at 0.005 can be avoided, and a computer simulation seems to show 0.005 is a pessimistic limit. For beams of reasonable smoothness on the edge, the actual limit should be somewhat higher. Some coupling effects due to the beam--beam interaction are also examined

  6. AIM for Allostery: Using the Ising Model to Understand Information Processing and Transmission in Allosteric Biomolecular Systems.

    Science.gov (United States)

    LeVine, Michael V; Weinstein, Harel

    2015-05-01

    In performing their biological functions, molecular machines must process and transmit information with high fidelity. Information transmission requires dynamic coupling between the conformations of discrete structural components within the protein positioned far from one another on the molecular scale. This type of biomolecular "action at a distance" is termed allostery . Although allostery is ubiquitous in biological regulation and signal transduction, its treatment in theoretical models has mostly eschewed quantitative descriptions involving the system's underlying structural components and their interactions. Here, we show how Ising models can be used to formulate an approach to allostery in a structural context of interactions between the constitutive components by building simple allosteric constructs we termed Allosteric Ising Models (AIMs). We introduce the use of AIMs in analytical and numerical calculations that relate thermodynamic descriptions of allostery to the structural context, and then show that many fundamental properties of allostery, such as the multiplicative property of parallel allosteric channels, are revealed from the analysis of such models. The power of exploring mechanistic structural models of allosteric function in more complex systems by using AIMs is demonstrated by building a model of allosteric signaling for an experimentally well-characterized asymmetric homodimer of the dopamine D2 receptor.

  7. Underlying thermodynamics of pH-dependent allostery.

    Science.gov (United States)

    Di Russo, Natali V; Martí, Marcelo A; Roitberg, Adrian E

    2014-11-13

    Understanding the effects of coupling protein protonation and conformational states is critical to the development of drugs targeting pH sensors and to the rational engineering of pH switches. In this work, we address this issue by performing a comprehensive study of the pH-regulated switch from the closed to the open conformation in nitrophorin 4 (NP4) that determines its pH-dependent activity. Our calculations show that D30 is the only amino acid that has two significantly different pKas in the open and closed conformations, confirming its critical role in regulating pH-dependent behavior. In addition, we describe the free-energy landscape of the conformational change as a function of pH, obtaining accurate estimations of free-energy barriers and equilibrium constants using different methods. The underlying thermodynamic model of the switch workings suggests the possibility of tuning the observed pKa only through the conformational equilibria, keeping the same conformation-specific pKas, as evidenced by the proposed K125L mutant. Moreover, coupling between the protonation and conformational equilibria results in efficient regulation and pH-sensing around physiological pH values only for some combinations of protonation and conformational equilibrium constants, placing constraints on their possible values and leaving a narrow space for protein molecular evolution. The calculations and analysis presented here are of general applicability and provide a guide as to how more complex systems can be studied, offering insight into how pH-regulated allostery works of great value for designing drugs that target pH sensors and for rational engineering of pH switches beyond the common histidine trigger.

  8. Long Distance Modulation of Disorder-to-Order Transitions in Protein Allostery.

    Science.gov (United States)

    Wang, Jingheng; Custer, Gregory; Beckett, Dorothy; Matysiak, Silvina

    2017-08-29

    Elucidation of the molecular details of allosteric communication between distant sites in a protein is key to understanding and manipulating many biological regulatory processes. Although protein disorder is acknowledged to play an important thermodynamic role in allostery, the molecular mechanisms by which this disorder is harnessed for long distance communication are known for a limited number of systems. Transcription repression by the Escherichia coli biotin repressor, BirA, is allosterically activated by binding of the small molecule effector biotinoyl-5'-AMP. The effector acts by promoting BirA dimerization, which is a prerequisite for sequence-specific binding to the biotin biosynthetic operon operator sequence. A 30 Å distance separates the effector binding and dimerization surfaces in BirA, and previous studies indicate that allostery is mediated, in part, by disorder-to-order transitions on the two coupled sites. In this work, combined experimental and computational methods have been applied to investigate the molecular basis of allosteric communication in BirA. Double-mutant cycle analysis coupled with thermodynamic measurements indicates functional coupling between residues in disordered loops on the two distant surfaces. All atom molecular dynamics simulations reveal that this coupling occurs through long distance reciprocal modulation of the structure and dynamics of disorder-to-order transitions on the two surfaces.

  9. Global low-frequency motions in protein allostery: CAP as a model system.

    Science.gov (United States)

    Townsend, Philip D; Rodgers, Thomas L; Pohl, Ehmke; Wilson, Mark R; McLeish, Tom C B; Cann, Martin J

    2015-06-01

    Allostery is a fundamental process by which ligand binding to a protein alters its activity at a distant site. There is considerable evidence that allosteric cooperativity can be communicated by the modulation of protein dynamics without conformational change. The Catabolite Activator Protein (CAP) of Escherichia coli is an important experimental exemplar for entropically driven allostery. Here we discuss recent experimentally supported theoretical analysis that highlights the role of global low-frequency dynamics in allostery in CAP and identify how allostery arises as a natural consequence of changes in global low-frequency protein fluctuations on ligand binding.

  10. Performance limitations of relay neurons.

    Directory of Open Access Journals (Sweden)

    Rahul Agarwal

    Full Text Available Relay cells are prevalent throughout sensory systems and receive two types of inputs: driving and modulating. The driving input contains receptive field properties that must be transmitted while the modulating input alters the specifics of transmission. For example, the visual thalamus contains relay neurons that receive driving inputs from the retina that encode a visual image, and modulating inputs from reticular activating system and layer 6 of visual cortex that control what aspects of the image will be relayed back to visual cortex for perception. What gets relayed depends on several factors such as attentional demands and a subject's goals. In this paper, we analyze a biophysical based model of a relay cell and use systems theoretic tools to construct analytic bounds on how well the cell transmits a driving input as a function of the neuron's electrophysiological properties, the modulating input, and the driving signal parameters. We assume that the modulating input belongs to a class of sinusoidal signals and that the driving input is an irregular train of pulses with inter-pulse intervals obeying an exponential distribution. Our analysis applies to any [Formula: see text] order model as long as the neuron does not spike without a driving input pulse and exhibits a refractory period. Our bounds on relay reliability contain performance obtained through simulation of a second and third order model, and suggest, for instance, that if the frequency of the modulating input increases or the DC offset decreases, then relay increases. Our analysis also shows, for the first time, how the biophysical properties of the neuron (e.g. ion channel dynamics define the oscillatory patterns needed in the modulating input for appropriately timed relay of sensory information. In our discussion, we describe how our bounds predict experimentally observed neural activity in the basal ganglia in (i health, (ii in Parkinson's disease (PD, and (iii in PD during

  11. Analysis of performance limitations for superconducting cavities

    International Nuclear Information System (INIS)

    J. R. Delayen; L. R. Doolittle; C. E. Reece

    1998-01-01

    The performance of superconducting cavities in accelerators can be limited by several factors, such as: field emission, quenches, arcing, rf power; and the maximum gradient at which a cavity can operate will be determined by the lowest of these limitations for that particular cavity. The CEBAF accelerator operates with over 300 cavities and, for each of them, the authors have determined the maximum operating gradient and its limiting factor. They have developed a model that allows them to determine the distribution of gradients that could be achieved for each of these limitations independently of the others. The result of this analysis can guide an R and D program to achieve the best overall performance improvement. The same model can be used to relate the performance of single-cell and multi-cell cavities

  12. Performance limitations of translationally symmetric nonimaging devices

    Science.gov (United States)

    Bortz, John C.; Shatz, Narkis E.; Winston, Roland

    2001-11-01

    The component of the optical direction vector along the symmetry axis is conserved for all rays propagated through a translationally symmetric optical device. This quality, referred to herein as the translational skew invariant, is analogous to the conventional skew invariant, which is conserved in rotationally symmetric optical systems. The invariance of both of these quantities is a consequence of Noether's theorem. We show how performance limits for translationally symmetric nonimaging optical devices can be derived from the distributions of the translational skew invariant for the optical source and for the target to which flux is to be transferred. Examples of computed performance limits are provided. In addition, we show that a numerically optimized non-tracking solar concentrator utilizing symmetry-breaking surface microstructure can overcome the performance limits associated with translational symmetry. The optimized design provides a 47.4% increase in efficiency and concentration relative to an ideal translationally symmetric concentrator.

  13. Cooperative DNA Recognition Modulated by an Interplay between Protein-Protein Interactions and DNA-Mediated Allostery.

    Directory of Open Access Journals (Sweden)

    Felipe Merino

    2015-06-01

    Full Text Available Highly specific transcriptional regulation depends on the cooperative association of transcription factors into enhanceosomes. Usually, their DNA-binding cooperativity originates from either direct interactions or DNA-mediated allostery. Here, we performed unbiased molecular simulations followed by simulations of protein-DNA unbinding and free energy profiling to study the cooperative DNA recognition by OCT4 and SOX2, key components of enhanceosomes in pluripotent cells. We found that SOX2 influences the orientation and dynamics of the DNA-bound configuration of OCT4. In addition SOX2 modifies the unbinding free energy profiles of both DNA-binding domains of OCT4, the POU specific and POU homeodomain, despite interacting directly only with the first. Thus, we demonstrate that the OCT4-SOX2 cooperativity is modulated by an interplay between protein-protein interactions and DNA-mediated allostery. Further, we estimated the change in OCT4-DNA binding free energy due to the cooperativity with SOX2, observed a good agreement with experimental measurements, and found that SOX2 affects the relative DNA-binding strength of the two OCT4 domains. Based on these findings, we propose that available interaction partners in different biological contexts modulate the DNA exploration routes of multi-domain transcription factors such as OCT4. We consider the OCT4-SOX2 cooperativity as a paradigm of how specificity of transcriptional regulation is achieved through concerted modulation of protein-DNA recognition by different types of interactions.

  14. Revealing Atomic-Level Mechanisms of Protein Allostery with Molecular Dynamics Simulations.

    Directory of Open Access Journals (Sweden)

    Samuel Hertig

    2016-06-01

    Full Text Available Molecular dynamics (MD simulations have become a powerful and popular method for the study of protein allostery, the widespread phenomenon in which a stimulus at one site on a protein influences the properties of another site on the protein. By capturing the motions of a protein's constituent atoms, simulations can enable the discovery of allosteric binding sites and the determination of the mechanistic basis for allostery. These results can provide a foundation for applications including rational drug design and protein engineering. Here, we provide an introduction to the investigation of protein allostery using molecular dynamics simulation. We emphasize the importance of designing simulations that include appropriate perturbations to the molecular system, such as the addition or removal of ligands or the application of mechanical force. We also demonstrate how the bidirectional nature of allostery-the fact that the two sites involved influence one another in a symmetrical manner-can facilitate such investigations. Through a series of case studies, we illustrate how these concepts have been used to reveal the structural basis for allostery in several proteins and protein complexes of biological and pharmaceutical interest.

  15. Mapping allostery through computational glycine scanning and correlation analysis of residue-residue contacts.

    Science.gov (United States)

    Johnson, Quentin R; Lindsay, Richard J; Nellas, Ricky B; Fernandez, Elias J; Shen, Tongye

    2015-02-24

    Understanding allosteric mechanisms is essential for the physical control of molecular switches and downstream cellular responses. However, it is difficult to decode essential allosteric motions in a high-throughput scheme. A general two-pronged approach to performing automatic data reduction of simulation trajectories is presented here. The first step involves coarse-graining and identifying the most dynamic residue-residue contacts. The second step is performing principal component analysis of these contacts and extracting the large-scale collective motions expressed via these residue-residue contacts. We demonstrated the method using a protein complex of nuclear receptors. Using atomistic modeling and simulation, we examined the protein complex and a set of 18 glycine point mutations of residues that constitute the binding pocket of the ligand effector. The important motions that are responsible for the allostery are reported. In contrast to conventional induced-fit and lock-and-key binding mechanisms, a novel "frustrated-fit" binding mechanism of RXR for allosteric control was revealed.

  16. Origins of Allostery and Evolvability in Proteins: A Case Study.

    Science.gov (United States)

    Raman, Arjun S; White, K Ian; Ranganathan, Rama

    2016-07-14

    Proteins display the capacity for adaptation to new functions, a property critical for evolvability. But what structural principles underlie the capacity for adaptation? Here, we show that adaptation to a physiologically distinct class of ligand specificity in a PSD95, DLG1, ZO-1 (PDZ) domain preferentially occurs through class-bridging intermediate mutations located distant from the ligand-binding site. These mutations provide a functional link between ligand classes and demonstrate the principle of "conditional neutrality" in mediating evolutionary adaptation. Structures show that class-bridging mutations work allosterically to open up conformational plasticity at the active site, permitting novel functions while retaining existing function. More generally, the class-bridging phenotype arises from mutations in an evolutionarily conserved network of coevolving amino acids in the PDZ family (the sector) that connects the active site to distant surface sites. These findings introduce the concept that allostery in proteins could have its origins not in protein function but in the capacity to adapt. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Rigid Residue Scan Simulations Systematically Reveal Residue Entropic Roles in Protein Allostery.

    Directory of Open Access Journals (Sweden)

    Robert Kalescky

    2016-04-01

    Full Text Available Intra-protein information is transmitted over distances via allosteric processes. This ubiquitous protein process allows for protein function changes due to ligand binding events. Understanding protein allostery is essential to understanding protein functions. In this study, allostery in the second PDZ domain (PDZ2 in the human PTP1E protein is examined as model system to advance a recently developed rigid residue scan method combining with configurational entropy calculation and principal component analysis. The contributions from individual residues to whole-protein dynamics and allostery were systematically assessed via rigid body simulations of both unbound and ligand-bound states of the protein. The entropic contributions of individual residues to whole-protein dynamics were evaluated based on covariance-based correlation analysis of all simulations. The changes of overall protein entropy when individual residues being held rigid support that the rigidity/flexibility equilibrium in protein structure is governed by the La Châtelier's principle of chemical equilibrium. Key residues of PDZ2 allostery were identified with good agreement with NMR studies of the same protein bound to the same peptide. On the other hand, the change of entropic contribution from each residue upon perturbation revealed intrinsic differences among all the residues. The quasi-harmonic and principal component analyses of simulations without rigid residue perturbation showed a coherent allosteric mode from unbound and bound states, respectively. The projection of simulations with rigid residue perturbation onto coherent allosteric modes demonstrated the intrinsic shifting of ensemble distributions supporting the population-shift theory of protein allostery. Overall, the study presented here provides a robust and systematic approach to estimate the contribution of individual residue internal motion to overall protein dynamics and allostery.

  18. Metabolic factors limiting performance in marathon runners.

    Science.gov (United States)

    Rapoport, Benjamin I

    2010-10-21

    Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as 'hitting the wall'), and thousands drop out before reaching the finish lines (approximately 1-2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making 'hitting the wall' seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without 'hitting the wall.' The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding 'the wall.' The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.

  19. Metabolic factors limiting performance in marathon runners.

    Directory of Open Access Journals (Sweden)

    Benjamin I Rapoport

    2010-10-01

    Full Text Available Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers, more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as 'hitting the wall', and thousands drop out before reaching the finish lines (approximately 1-2% of those who start. Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making 'hitting the wall' seem inevitable, or implied that maximal glycogen loading is required in order to complete a marathon without 'hitting the wall.' The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding 'the wall.' The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.

  20. Allostery and cooperativity in the interaction of drugs with ionic channel receptors

    Czech Academy of Sciences Publication Activity Database

    Krůšek, Jan

    2004-01-01

    Roč. 53, č. 6 (2004), s. 569-579 ISSN 0862-8408 R&D Projects: GA ČR GA202/02/1213; GA ČR GA305/02/1333 Institutional research plan: CEZ:AV0Z5011922 Keywords : allostery * hill coefficient * affinity Subject RIV: ED - Physiology Impact factor: 1.140, year: 2004

  1. Order-disorder transitions govern kinetic cooperativity and allostery of monomeric human glucokinase.

    Directory of Open Access Journals (Sweden)

    Mioara Larion

    Full Text Available Glucokinase (GCK catalyzes the rate-limiting step of glucose catabolism in the pancreas, where it functions as the body's principal glucose sensor. GCK dysfunction leads to several potentially fatal diseases including maturity-onset diabetes of the young type II (MODY-II and persistent hypoglycemic hyperinsulinemia of infancy (PHHI. GCK maintains glucose homeostasis by displaying a sigmoidal kinetic response to increasing blood glucose levels. This positive cooperativity is unique because the enzyme functions exclusively as a monomer and possesses only a single glucose binding site. Despite nearly a half century of research, the mechanistic basis for GCK's homotropic allostery remains unresolved. Here we explain GCK cooperativity in terms of large-scale, glucose-mediated disorder-order transitions using 17 isotopically labeled isoleucine methyl groups and three tryptophan side chains as sensitive nuclear magnetic resonance (NMR probes. We find that the small domain of unliganded GCK is intrinsically disordered and samples a broad conformational ensemble. We also demonstrate that small-molecule diabetes therapeutic agents and hyperinsulinemia-associated GCK mutations share a strikingly similar activation mechanism, characterized by a population shift toward a more narrow, well-ordered ensemble resembling the glucose-bound conformation. Our results support a model in which GCK generates its cooperative kinetic response at low glucose concentrations by using a millisecond disorder-order cycle of the small domain as a "time-delay loop," which is bypassed at high glucose concentrations, providing a unique mechanism to allosterically regulate the activity of human GCK under physiological conditions.

  2. Limitations in dual-task performance

    NARCIS (Netherlands)

    Pannebakker, Merel Mathilde

    2009-01-01

    In this thesis, the effect of information-processing overload on working-memory dependent information processing was examined using dual-task paradigms. The experiments described strengthen the importance of a functional explanation for dual-task limitations. First, it showed evidence for a unified

  3. Metamaterial polarization converter analysis: limits of performance

    DEFF Research Database (Denmark)

    Markovich, Dmitry L.; Andryieuski, Andrei; Zalkovskij, Maksim

    2013-01-01

    and a single layer with a ground plane can have 100 % polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design......In this paper, we analyze the theoretical limits of a metamaterial-based converter with orthogonal linear eigenpolarizations that allow linear-to-elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed...... level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50 %, while the realistic reflection configuration can give the conversion efficiency up to 90 %. We show that a double layer transmission converter...

  4. Limitations in dual-task performance

    OpenAIRE

    Pannebakker, Merel Mathilde

    2009-01-01

    In this thesis, the effect of information-processing overload on working-memory dependent information processing was examined using dual-task paradigms. The experiments described strengthen the importance of a functional explanation for dual-task limitations. First, it showed evidence for a unified coding medium (as put forward in the theory of event coding; Hommel, Müsseler, Aschersleben, & Prinz, 2001) in which features, operations and responses are available and can influence each other. A...

  5. Performance Limits of Communication with Energy Harvesting

    KAUST Repository

    Znaidi, Mohamed Ridha

    2016-01-01

    In energy harvesting communications, the transmitters have to adapt transmission to the availability of energy harvested during communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility

  6. Performance Limits of Communication with Energy Harvesting

    KAUST Repository

    Znaidi, Mohamed Ridha

    2016-04-01

    In energy harvesting communications, the transmitters have to adapt transmission to the availability of energy harvested during communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. During this work, we consider the problem of power allocation taking into account the energy arrivals over time and the quality of channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the energy harvesting constraints. Assuming a perfect knowledge of the CSI at the receiver, we determine the optimal power policy for different models of the energy arrival process (offline and online model). Indeed, we obtain the power allocation scheme when the transmitter has either perfect CSI or no CSI. We also investigate of utmost interest the case of fading channels with imperfect CSI. Moreover, a study of the asymptotic behavior of the communication system is proposed. Specifically, we analyze of the average throughput in a system where the average recharge rate goes asymptotically to zero and when it is very high.

  7. Whole-protein alanine-scanning mutagenesis of allostery: A large percentage of a protein can contribute to mechanism.

    Science.gov (United States)

    Tang, Qingling; Fenton, Aron W

    2017-09-01

    Many studies of allosteric mechanisms use limited numbers of mutations to test whether residues play "key" roles. However, if a large percentage of the protein contributes to allosteric function, mutating any residue would have a high probability of modifying allostery. Thus, a predicted mechanism that is dependent on only a few residues could erroneously appear to be supported. We used whole-protein alanine-scanning mutagenesis to determine which amino acid sidechains of human liver pyruvate kinase (hL-PYK; approved symbol PKLR) contribute to regulation by fructose-1,6-bisphosphate (Fru-1,6-BP; activator) and alanine (inhibitor). Each nonalanine/nonglycine residue of hL-PYK was mutated to alanine to generate 431 mutant proteins. Allosteric functions in active proteins were quantified by following substrate affinity over a concentration range of effectors. Results show that different residues contribute to the two allosteric functions. Only a small fraction of mutated residues perturbed inhibition by alanine. In contrast, a large percentage of mutated residues influenced activation by Fru-1,6-BP; inhibition by alanine is not simply the reverse of activation by Fru-1,6-BP. Moreover, the results show that Fru-1,6-BP activation would be extremely difficult to elucidate using a limited number of mutations. Additionally, this large mutational data set will be useful to train and test computational algorithms aiming to predict allosteric mechanisms. © 2017 Wiley Periodicals, Inc.

  8. Effect of beta limits on reactor performance in EBT

    International Nuclear Information System (INIS)

    Uckan, N.A.; Spong, D.A.; Nelson, D.B.

    1981-01-01

    Because of uncertainties in extrapolating results of simplified models to a reactor plasma, the parameters that influence the beta limits cannot be determined accurately at the present time. Also, the reasonable changes within the models and/or assumptions are seen to affect the core beta limits by almost an order of magnitde. Hence, at the present, these limits cannot be used as a rigid (and reliable) requirement for ELMO Bumpy Torus (EBT) reactor engineering considerations. However, sensitivity studies can be carried out to determine the boundaries of the operating regime and to demonstrate the effects of various modes, assumptions, and models on reactor performance (Q value). First, the modes believed to limit the core β and ring plasma performance are discussed, and the simplifications and/or assumptions involved in deriving these limits are highlighted. Then, the implications of these limits for a reactor are given

  9. Doublet III limiter performance and implications for mechanical design and material selection for future limiters

    International Nuclear Information System (INIS)

    Sabado, M.M.; Marcus, F.B.; Trester, P.W.; Wesley, J.C.

    1979-10-01

    The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter material for evaluation. Design and material selection criteria for the different Z ranges are presented. The performance of the high-Z limiters in Doublet III is reviewed for an operation period that included approximately 5000 plasma shots. Changes in surface appearance and metallurgical changes are characterized. Discussion is presented on how and to what extent the high-Z elements affected the performance of the plasma based on theory and measurements in Doublet III. The fabrication processes for the Inconel X-750 limiters are summarized, and, last, observations on early performance of the Inconel limiters are described

  10. Doublet III limiter performance and implications for mechanical design and material selection for future limiters

    Energy Technology Data Exchange (ETDEWEB)

    Sabado, M.M.; Marcus, F.B.; Trester, P.W.; Wesley, J.C.

    1979-10-01

    The plasma limiter system for Doublet III is described. Initially, high-Z materials, Ta-10W for the primary limiter and Mo for the backup limiters, were selected as the most attractive metallic candidates from the standpoint of thermal and structural properties. For the purpose of evaluating the effect of material Z on plasma performance, the nonmagnetic, Ni-base alloy Inconel X-750 was selected for a medium-Z limiter material. Graphite, a low-Z material, will likely be the next limiter material for evaluation. Design and material selection criteria for the different Z ranges are presented. The performance of the high-Z limiters in Doublet III is reviewed for an operation period that included approximately 5000 plasma shots. Changes in surface appearance and metallurgical changes are characterized. Discussion is presented on how and to what extent the high-Z elements affected the performance of the plasma based on theory and measurements in Doublet III. The fabrication processes for the Inconel X-750 limiters are summarized, and, last, observations on early performance of the Inconel limiters are described. (MOW)

  11. Conformational Rigidity and Protein Dynamics at Distinct Timescales Regulate PTP1B Activity and Allostery.

    Science.gov (United States)

    Choy, Meng S; Li, Yang; Machado, Luciana E S F; Kunze, Micha B A; Connors, Christopher R; Wei, Xingyu; Lindorff-Larsen, Kresten; Page, Rebecca; Peti, Wolfgang

    2017-02-16

    Protein function originates from a cooperation of structural rigidity, dynamics at different timescales, and allostery. However, how these three pillars of protein function are integrated is still only poorly understood. Here we show how these pillars are connected in Protein Tyrosine Phosphatase 1B (PTP1B), a drug target for diabetes and cancer that catalyzes the dephosphorylation of numerous substrates in essential signaling pathways. By combining new experimental and computational data on WT-PTP1B and ≥10 PTP1B variants in multiple states, we discovered a fundamental and evolutionarily conserved CH/π switch that is critical for positioning the catalytically important WPD loop. Furthermore, our data show that PTP1B uses conformational and dynamic allostery to regulate its activity. This shows that both conformational rigidity and dynamics are essential for controlling protein activity. This connection between rigidity and dynamics at different timescales is likely a hallmark of all enzyme function. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Operational limitations of light water reactors relating to fuel performance

    International Nuclear Information System (INIS)

    Cheng, H.S.

    1976-07-01

    General aspects of fuel performance for typical Boiling and Pressurized Water Reactors are presented. Emphasis is placed on fuel failures in order to make clear important operational limitations. A discussion of fuel element designs is first given to provide the background information for the subsequent discussion of several fuel failure modes that have been identified. Fuel failure experiences through December 31, 1974, are summarized. The operational limitations that are required to mitigate the effects of fuel failures are discussed

  13. Performance limits for maritime Inverse Synthetic Aperture Radar (ISAR)

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-11-01

    The performance of an Inverse Synthetic Aperture Radar (ISAR) system depends on a variety of factors, many which are interdependent in some manner. In this report we specifically examine ISAR as applied to maritime targets (e.g. ships). It is often difficult to get your arms around the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall ISAR system. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the seek time.

  14. The Limits of Exercise Physiology: From Performance to Health.

    Science.gov (United States)

    Gabriel, Brendan M; Zierath, Juleen R

    2017-05-02

    Many of the established positive health benefits of exercise have been documented by historical discoveries in the field of exercise physiology. These investigations often assess limits: the limits of performance, or the limits of exercise-induced health benefits. Indeed, several key findings have been informed by studying highly trained athletes, in addition to healthy or unhealthy people. Recent progress has been made in regard to skeletal muscle metabolism and personalized exercise regimes. In this perspective, we review some of the historical milestones of exercise physiology, discuss how these inform contemporary knowledge, and speculate on future questions. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Allostery Is an Intrinsic Property of the Protease Domain of DegS Implications for Enzyme Function and Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Jungsan; Grant, Robert A.; Sauer, Robert T. (MIT)

    2010-12-02

    DegS is a periplasmic Escherichia coli protease, which functions as a trimer to catalyze the initial rate-limiting step in a proteolytic cascade that ultimately activates transcription of stress response genes in the cytoplasm. Each DegS subunit consists of a protease domain and a PDZ domain. During protein folding stress, DegS is allosterically activated by peptides exposed in misfolded outer membrane porins, which bind to the PDZ domain and stabilize the active protease. It is not known whether allostery is conferred by the PDZ domains or is an intrinsic feature of the trimeric protease domain. Here, we demonstrate that free DegS{sup {Delta}PDZ} equilibrates between active and inactive trimers with the latter species predominating. Substrate binding stabilizes active DegS{sup {Delta}PDZ} in a positively cooperative fashion. Mutations can also stabilize active DegS{sup {Delta}PDZ} and produce an enzyme that displays hyperbolic kinetics and degrades substrate with a maximal velocity within error of that for fully activated, intact DegS. Crystal structures of multiple DegS{sup {Delta}PDZ} variants, in functional and non-functional conformations, support a two-state model in which allosteric switching is mediated by changes in specific elements of tertiary structure in the context of an invariant trimeric base. Overall, our results indicate that protein substrates must bind sufficiently tightly and specifically to the functional conformation of DegS{sup {Delta}PDZ} to assist their own degradation. Thus, substrate binding alone may have regulated the activities of ancestral DegS trimers with subsequent fusion of the protease domain to a PDZ domain, resulting in ligand-mediated regulation.

  16. High temperature performance limit of containment system of transport cask

    International Nuclear Information System (INIS)

    Kato, Osamu; Saegusa, Toshiari

    1998-01-01

    The containment performance of a containment system using elastomer gaskets for transport casks under a high temperature and high pressure was clarified. Major results are as follows; (1) The deformation characteristics of the gaskets were represented by the compressive permanent strain rate (Dp). The temperature and time dependence was shown by Larson-Miller Parameter (LMP). (2) Generally, the high temperature performance limit is obtained by a value of LMP when the Dp value reaches 80%. However, the gaskets (FKM, VMQ, EPDM) used for real transport casks were not damaged and the containment performance was not deteriorated as a conservative condition. (3) Assuming that the service period of the gaskets for transport casks is 3 months or 1 year, the high temperature performance limit of the gasket made of fluorine rubber (FKM) is 202degC or 182degC, respectively, which includes safety margin. (author)

  17. Performance limits for fusion first-wall structural materials

    International Nuclear Information System (INIS)

    Smith, D.L.; Majumdar, S.; Billone, M.; Mattas, R.

    2000-01-01

    Key features of fusion energy relate primarily to potential advantages associated with safety and environmental considerations and the near endless supply of fuel. However, high-performance fusion power systems will be required in order to be an economically competitive energy option. As in most energy systems, the operating limits of structural materials pose a primary constraint to the performance of fusion power systems. In the case of fusion power, the first-wall/blanket system will have a dominant impact on both economic and safety/environmental attractiveness. This paper presents an assessment of the influence of key candidate structural material properties on performance limits for fusion first-wall blanket applications. Key issues associated with interactions of the structural materials with the candidate coolant/breeder materials are discussed

  18. Implementation of the NMR CHEmical Shift Covariance Analysis (CHESCA): A Chemical Biologist's Approach to Allostery.

    Science.gov (United States)

    Boulton, Stephen; Selvaratnam, Rajeevan; Ahmed, Rashik; Melacini, Giuseppe

    2018-01-01

    Mapping allosteric sites is emerging as one of the central challenges in physiology, pathology, and pharmacology. Nuclear Magnetic Resonance (NMR) spectroscopy is ideally suited to map allosteric sites, given its ability to sense at atomic resolution the dynamics underlying allostery. Here, we focus specifically on the NMR CHEmical Shift Covariance Analysis (CHESCA), in which allosteric systems are interrogated through a targeted library of perturbations (e.g., mutations and/or analogs of the allosteric effector ligand). The atomic resolution readout for the response to such perturbation library is provided by NMR chemical shifts. These are then subject to statistical correlation and covariance analyses resulting in clusters of allosterically coupled residues that exhibit concerted responses to the common set of perturbations. This chapter provides a description of how each step in the CHESCA is implemented, starting from the selection of the perturbation library and ending with an overview of different clustering options.

  19. Reactivity limitations on the performance of hybrid reactors

    International Nuclear Information System (INIS)

    Piera, M.; Martinez-Val, J.M.

    1994-01-01

    A neutronic theory for characterizing the hybrid blanket physics is used to show that hybrid performances are limited because of reactivity restrictions. The hybrid must always remain subcritical, even in abnormal conditions. For hybrids devoted to energy production by multiplication of the neutron source power, the restriction is particularly strong, and the electricity recirculation fraction to feed the plant can be too large for its economic feasibility. In hybrids used to breed fissile fuel, the power of LWR maintained by power unit of the hybrid is also limited (to a factor of 10, approx.). (author)

  20. Dynamic Allostery Mediated by a Conserved Tryptophan in the Tec Family Kinases.

    Directory of Open Access Journals (Sweden)

    Nikita Chopra

    2016-03-01

    Full Text Available Bruton's tyrosine kinase (Btk is a Tec family non-receptor tyrosine kinase that plays a critical role in immune signaling and is associated with the immunological disorder X-linked agammaglobulinemia (XLA. Our previous findings showed that the Tec kinases are allosterically activated by the adjacent N-terminal linker. A single tryptophan residue in the N-terminal 17-residue linker mediates allosteric activation, and its mutation to alanine leads to the complete loss of activity. Guided by hydrogen/deuterium exchange mass spectrometry results, we have employed Molecular Dynamics simulations, Principal Component Analysis, Community Analysis and measures of node centrality to understand the details of how a single tryptophan mediates allostery in Btk. A specific tryptophan side chain rotamer promotes the functional dynamic allostery by inducing coordinated motions that spread across the kinase domain. Either a shift in the rotamer population, or a loss of the tryptophan side chain by mutation, drastically changes the coordinated motions and dynamically isolates catalytically important regions of the kinase domain. This work also identifies a new set of residues in the Btk kinase domain with high node centrality values indicating their importance in transmission of dynamics essential for kinase activation. Structurally, these node residues appear in both lobes of the kinase domain. In the N-lobe, high centrality residues wrap around the ATP binding pocket connecting previously described Catalytic-spine residues. In the C-lobe, two high centrality node residues connect the base of the R- and C-spines on the αF-helix. We suggest that the bridging residues that connect the catalytic and regulatory architecture within the kinase domain may be a crucial element in transmitting information about regulatory spine assembly to the catalytic machinery of the catalytic spine and active site.

  1. High performance discharges near the operational limit in HT-7

    International Nuclear Information System (INIS)

    Li Jiangang; Wan Baonian; Luo Jiarong; Gao Xiang; Zhao Yanping; Kuang Guangli; Zhang Xiaodong; Yang Yu; Yi Bao; Bojiang Ding; Jikang Xie; Yuanxi Wan

    2001-01-01

    Efforts have been made on the HT-7 tokamak to extend the stable operation boundaries. Extensive RF boronization and siliconization have been used and a wider operational Hugill diagram has been obtained. The transit density reached 1.3 times the Greenwald density limit in ohmic discharges. A stationary high performance discharge with q a =2.1 has been obtained after siliconization. Confinement improvement was obtained as a result of the significant reduction of electron thermal diffusivity χ e in the outer region of the plasma. An improved confinement phase was also observed with LHCD in the density range of 70-120% of the Greenwald density limit. Off-axis LH wave power deposition was attributed to the weak hollow current density profile. Code simulations and measurements showed good agreement with the off-axis LH wave deposition. Supersonic molecular beam injection has been successfully used to achieve stable high density operation in the region of the Greenwald density limit. (author)

  2. Performance limit of daytime radiative cooling in warm humid environment

    Directory of Open Access Journals (Sweden)

    Takahiro Suichi

    2018-05-01

    Full Text Available Daytime radiative cooling potentially offers efficient passive cooling, but the performance is naturally limited by the environment, such as the ambient temperature and humidity. Here, we investigate the performance limit of daytime radiative cooling under warm and humid conditions in Okayama, Japan. A cooling device, consisting of alternating layers of SiO2 and poly(methyl methacrylate on an Al mirror, is fabricated and characterized to demonstrate a high reflectance for sunlight and a selective thermal radiation in the mid-infrared region. In the temperature measurement under the sunlight irradiation, the device shows 3.4 °C cooler than a bare Al mirror, but 2.8 °C warmer than the ambient of 35 °C. The corresponding numerical analyses reveal that the atmospheric window in λ = 16 ∼ 25 μm is closed due to a high humidity, thereby limiting the net emission power of the device. Our study on the humidity influence on the cooling performance provides a general guide line of how one can achieve practical passive cooling in a warm humid environment.

  3. Conformational Changes in the Hepatitis B Virus Core Protein Are Consistent with a Role for Allostery in Virus Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Packianathan, Charles; Katen, Sarah P.; Dann, III, Charles E.; Zlotnick, Adam (Indiana)

    2010-01-12

    In infected cells, virus components must be organized at the right place and time to ensure assembly of infectious virions. From a different perspective, assembly must be prevented until all components are available. Hypothetically, this can be achieved by allosterically controlling assembly. Consistent with this hypothesis, here we show that the structure of the hepatitis B virus (HBV) core protein dimer, which can spontaneously self-assemble, is incompatible with capsid assembly. Systematic differences between core protein dimer and capsid conformations demonstrate linkage between the intradimer interface and interdimer contact surface. These structures also provide explanations for the capsid-dimer selectivity of some antibodies and the activities of assembly effectors. Solution studies suggest that the assembly-inactive state is more accurately an ensemble of conformations. Simulations show that allostery supports controlled assembly and results in capsids that are resistant to dissociation. We propose that allostery, as demonstrated in HBV, is common to most self-assembling viruses.

  4. The 'sensory tolerance limit': A hypothetical construct determining exercise performance?

    Science.gov (United States)

    Hureau, Thomas J; Romer, Lee M; Amann, Markus

    2018-02-01

    Neuromuscular fatigue compromises exercise performance and is determined by central and peripheral mechanisms. Interactions between the two components of fatigue can occur via neural pathways, including feedback and feedforward processes. This brief review discusses the influence of feedback and feedforward mechanisms on exercise limitation. In terms of feedback mechanisms, particular attention is given to group III/IV sensory neurons which link limb muscle with the central nervous system. Central corollary discharge, a copy of the neural drive from the brain to the working muscles, provides a signal from the motor system to sensory systems and is considered a feedforward mechanism that might influence fatigue and consequently exercise performance. We highlight findings from studies supporting the existence of a 'critical threshold of peripheral fatigue', a previously proposed hypothesis based on the idea that a negative feedback loop operates to protect the exercising limb muscle from severe threats to homeostasis during whole-body exercise. While the threshold theory remains to be disproven within a given task, it is not generalisable across different exercise modalities. The 'sensory tolerance limit', a more theoretical concept, may address this issue and explain exercise tolerance in more global terms and across exercise modalities. The 'sensory tolerance limit' can be viewed as a negative feedback loop which accounts for the sum of all feedback (locomotor muscles, respiratory muscles, organs, and muscles not directly involved in exercise) and feedforward signals processed within the central nervous system with the purpose of regulating the intensity of exercise to ensure that voluntary activity remains tolerable.

  5. Knock-limited performance of several internal coolants

    Science.gov (United States)

    Bellman, Donald R; Evvard, John C

    1945-01-01

    The effect of internal cooling on the knock-limited performance of an-f-28 fuel was investigated in a CFR engine, and the following internal coolants were used: (1) water, (2), methyl alcohol-water mixture, (3) ammonia-methyl alcohol-water mixture, (4) monomethylamine-water mixture, (5) dimethylamine-water mixture, and (6) trimethylamine-water mixture. Tests were run at inlet-air temperatures of 150 degrees and 250 degrees F. to indicate the temperature sensitivity of the internal-coolant solutions.

  6. Performance and Lifetime Limiting Effects in Li-ion Batteries

    DEFF Research Database (Denmark)

    Scipioni, Roberto

    Lithium-ion batteries (LIBs) find widespread use for electricity storage, from portable devices such as smart phones to electric vehicles (EV), because of their high energy density and design flexibility. However, limited lifetime is still a challenge for several LIB materials. Specifically......, the detailed coupling between degradation mechanisms and battery usage is not fully understood, which impede lifetime improvements. To understand the degradation mechanisms and increase the performance of these materials, the development of improved characterization methods is crucial. This PhD thesis focuses...... on the thorough analysis of degradation mechanism in LIBs, trying to relate morphological and structural changes in Lithium-ion battery electrodes to performance degradation observed during electrode cycling. Degradation mechanisms in laboratory scale LFP cathodes were correlated with the degradation mechanisms...

  7. Effects of intermediate load on performance limitations in excitation control

    Directory of Open Access Journals (Sweden)

    Pichai Aree

    2008-05-01

    Full Text Available The stability of excitation control systems is of great concern in power system operations. In this paper, the effects of intermediate load on performance limitation in excitation control are studied. The results reveal that the open-loop characteristic of synchronous machine’s flux linkage can be changed from minimum to non-minimum phase at a high level of intermediate load. This change leads to instability of synchronous machines under manual excitation control. A particular emphasis is also given to investigate the fundamental limitations in excitation control, imposed by non-minimum phases with regard to the open-loop right-half-plane (ORHP pole. The study demonstrates the difficulties of excitation control tuning to achieve the desired performance and robustness under the ORHP pole occurrence. Moreover, this paper shows the conditional stability in excitation control loop, where either an increase or decrease of the exciter gain causes a destabilization of the system’s stability. Frequency response techniques are used for these investigations.

  8. Driving performance at lateral system limits during partially automated driving.

    Science.gov (United States)

    Naujoks, Frederik; Purucker, Christian; Wiedemann, Katharina; Neukum, Alexandra; Wolter, Stefan; Steiger, Reid

    2017-11-01

    This study investigated driver performance during system limits of partially automated driving. Using a motion-based driving simulator, drivers encountered different situations in which a partially automated vehicle could no longer safely keep the lateral guidance. Drivers were distracted by a non-driving related task on a touch display or driving without an additional secondary task. While driving in partially automated mode drivers could either take their hands off the steering wheel for only a short period of time (10s, so-called 'Hands-on' variant) or for an extended period of time (120s, so-called 'Hands-off' variant). When the system limit was reached (e.g., when entering a work zone with temporary lines), the lateral vehicle control by the automation was suddenly discontinued and a take-over request was issued to the drivers. Regardless of the hands-off interval and the availability of a secondary task, all drivers managed the transition to manual driving safely. No lane exceedances were observed and the situations were rated as 'harmless' by the drivers. The lack of difference between the hands-off intervals can be partly attributed to the fact that most of the drivers kept contact to the steering wheel, even in the hands-off condition. Although all drivers were able to control the system limits, most of them could not explain why exactly the take-over request was issued. The average helpfulness of the take-over request was rated on an intermediate level. Consequently, providing drivers with information about the reason for a system limit can be recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Performance limits of plasmon-enhanced organic photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Karatay, Durmus U.; Ginger, David S., E-mail: ginger@chem.washington.edu [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Salvador, Michael [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Yao, Kai [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States); Jen, Alex K.-Y. [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195 (United States)

    2014-07-21

    We use a combination of experiment and modeling to explore the promise and limitations of using plasmon-resonant metal nanoparticles to enhance the device performance of organic photovoltaics (OPVs). We focus on optical properties typical of the current generation of low-bandgap donor polymers blended with the fullerene (6,6)-phenyl C{sub 71}-butyric acid methyl ester (PC{sub 71}BM) and use the polymer poly(indacenodithiophene-co-phenanthro[9,10-b]quinoxaline) (PIDT-PhanQ) as our test case. We model the optical properties and performance of these devices both in the presence and absence of a variety of colloidal silver nanoparticles. We show that for these materials, device performance is sensitive to the relative z-position and the density of nanoparticles inside the active layer. Using conservative estimates of the internal quantum efficiency for the PIDT-PhanQ/PC{sub 71}BM blend, we calculate that optimally placed silver nanoparticles could yield an enhancement in short-circuit current density of over 31% when used with ∼ 80-nm-thick active layers, resulting in an absolute increase in power conversion efficiency of up to ∼2% for the device based on optical engineering.

  10. Born to run. Studying the limits of human performance

    Directory of Open Access Journals (Sweden)

    Murray Andrew

    2012-07-01

    Full Text Available Abstract It is recognised that regular physical activity and a high level of fitness are powerful predictors of positive health outcomes. There is a long and rich history of significant feats of human endurance with some, for example, the death of the first marathon runner, Pheidippides, associated with negative health outcomes. Early studies on endurance running used X-ray and interview techniques to evaluate competitors and comment on performance. Since then, comparatively few studies have looked at runners competing in distances longer than a marathon. Those that have, tend to show significant musculoskeletal injuries and a remarkable level of adaptation to this endurance load. The TransEurope Footrace Project followed ultra-endurance runners aiming to complete 4,500 Km of running in 64 days across Europe. This pioneering study will assess the impact of extreme endurance on human physiology; analysing musculoskeletal and other tissue/organ injuries, and the body's potential ability to adapt to extreme physiological stress. The results will be of interest not only to endurance runners, but to anyone interested in the limits of human performance. Please see related article: http://www.biomedcentral.com/1741-7015/10/78

  11. Entropy Transfer between Residue Pairs and Allostery in Proteins: Quantifying Allosteric Communication in Ubiquitin.

    Directory of Open Access Journals (Sweden)

    Aysima Hacisuleyman

    2017-01-01

    Full Text Available It has recently been proposed by Gunasakaran et al. that allostery may be an intrinsic property of all proteins. Here, we develop a computational method that can determine and quantify allosteric activity in any given protein. Based on Schreiber's transfer entropy formulation, our approach leads to an information transfer landscape for the protein that shows the presence of entropy sinks and sources and explains how pairs of residues communicate with each other using entropy transfer. The model can identify the residues that drive the fluctuations of others. We apply the model to Ubiquitin, whose allosteric activity has not been emphasized until recently, and show that there are indeed systematic pathways of entropy and information transfer between residues that correlate well with the activities of the protein. We use 600 nanosecond molecular dynamics trajectories for Ubiquitin and its complex with human polymerase iota and evaluate entropy transfer between all pairs of residues of Ubiquitin and quantify the binding susceptibility changes upon complex formation. We explain the complex formation propensities of Ubiquitin in terms of entropy transfer. Important residues taking part in allosteric communication in Ubiquitin predicted by our approach are in agreement with results of NMR relaxation dispersion experiments. Finally, we show that time delayed correlation of fluctuations of two interacting residues possesses an intrinsic causality that tells which residue controls the interaction and which one is controlled. Our work shows that time delayed correlations, entropy transfer and causality are the required new concepts for explaining allosteric communication in proteins.

  12. New open conformation of SMYD3 implicates conformational selection and allostery

    Directory of Open Access Journals (Sweden)

    Nicholas Spellmon

    2016-12-01

    Full Text Available SMYD3 plays a key role in cancer cell viability, adhesion, migration and invasion. SMYD3 promotes formation of inducible regulatory T cells and is involved in reducing autoimmunity. However, the nearly “closed” substrate-binding site and poor in vitro H3K4 methyltransferase activity have obscured further understanding of this oncogenically related protein. Here we reveal that SMYD3 can adopt an “open” conformation using molecular dynamics simulation and small-angle X-ray scattering. This ligand-binding-capable open state is related to the crystal structure-like closed state by a striking clamshell-like inter-lobe dynamics. The two states are characterized by many distinct structural and dynamical differences and the conformational transition pathway is mediated by a reversible twisting motion of the C-terminal domain (CTD. The spontaneous transition from the closed to open states suggests two possible, mutually non-exclusive models for SMYD3 functional regulation and the conformational selection mechanism and allostery may regulate the catalytic or ligand binding competence of SMYD3. This study provides an immediate clue to the puzzling role of SMYD3 in epigenetic gene regulation.

  13. Entropy Transfer between Residue Pairs and Allostery in Proteins: Quantifying Allosteric Communication in Ubiquitin.

    Science.gov (United States)

    Hacisuleyman, Aysima; Erman, Burak

    2017-01-01

    It has recently been proposed by Gunasakaran et al. that allostery may be an intrinsic property of all proteins. Here, we develop a computational method that can determine and quantify allosteric activity in any given protein. Based on Schreiber's transfer entropy formulation, our approach leads to an information transfer landscape for the protein that shows the presence of entropy sinks and sources and explains how pairs of residues communicate with each other using entropy transfer. The model can identify the residues that drive the fluctuations of others. We apply the model to Ubiquitin, whose allosteric activity has not been emphasized until recently, and show that there are indeed systematic pathways of entropy and information transfer between residues that correlate well with the activities of the protein. We use 600 nanosecond molecular dynamics trajectories for Ubiquitin and its complex with human polymerase iota and evaluate entropy transfer between all pairs of residues of Ubiquitin and quantify the binding susceptibility changes upon complex formation. We explain the complex formation propensities of Ubiquitin in terms of entropy transfer. Important residues taking part in allosteric communication in Ubiquitin predicted by our approach are in agreement with results of NMR relaxation dispersion experiments. Finally, we show that time delayed correlation of fluctuations of two interacting residues possesses an intrinsic causality that tells which residue controls the interaction and which one is controlled. Our work shows that time delayed correlations, entropy transfer and causality are the required new concepts for explaining allosteric communication in proteins.

  14. Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions.

    Science.gov (United States)

    Yang, Linlin; Jing, Xu; An, Bowen; He, Cheng; Yang, Yang; Duan, Chunying

    2018-01-28

    By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system.

  15. Performance limitations of polymer electrolytes based on ethylene oxide polymers

    International Nuclear Information System (INIS)

    Buriez, Olivier; Han, Yong Bong; Hou, Jun; Kerr, John B.; Qiao, Jun; Sloop, Steven E.; Tian, Minmin; Wang, Shanger

    1999-01-01

    Studies of polymer electrolyte solutions for lithium-polymer batteries are described. Two different salts, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium trifluoromethanesulfonate (LiTf), were dissolved in a variety of polymers. The structures were all based upon the ethylene oxide unit for lithium ion solvation and both linear and comb-branch polymer architectures have been examined. Conductivity, salt diffusion coefficient and transference number measurements demonstrate the superior transport properties of the LiTFSI salt over LiTf. Data obtained on all of these polymers combined with LiTFSI salts suggest that there is a limit to the conductivity achievable at room temperature, at least for hosts containing ethylene oxide units. The apparent conductivity limit is 5 x 10-5 S/cm at 25 C. Providing that the polymer chain segment containing the ethylene oxide units is at least 5-6 units long there appears to be little influence of the polymer framework to which the solvating groups are attached. To provide adequate separator function, the mechanical properties may be disconnected from the transport properties by selection of an appropriate architecture combined with an adequately long ethylene oxide chain. For both bulk and interfacial transport of the lithium ions, conductivity data alone is insufficient to understand the processes that occur. Lithium ion transference numbers and salt diffusion coefficients also play a major role in the observed behavior and the transport properties of these polymer electrolyte solutions appear to be quite inadequate for ambient temperature performance. At present, this restricts the use of such systems to high temperature applications. Several suggestions are given to overcome these obstacles

  16. Performance limiting effects in X-band accelerators

    Directory of Open Access Journals (Sweden)

    Faya Wang

    2011-01-01

    Full Text Available Acceleration gradient is a critical parameter for the design of future TeV-scale linear colliders. The major obstacle to higher gradient in room-temperature accelerators is rf breakdown, which is still a very mysterious phenomenon that depends on the geometry and material of the accelerator as well as the input power and operating frequency. Pulsed heating has been associated with breakdown for many years; however, there have been no experiments that clearly separate field and heating effects on the breakdown rate. Recently, such experiments have been performed at SLAC with both standing-wave and traveling-wave structures. These experiments have demonstrated that pulsed heating is limiting the gradient. Nevertheless the X-band structures breakdown studies show damage to the iris surfaces in locations of high electric field rather than of high magnetic field after thousands of breakdowns. It is not yet clear how the relative roles of electric field, magnetic field, and heating factor into the damage caused by rf breakdown. Thus, a dual-moded cavity has been designed to better study the electric field, magnetic field, and pulsed heating effects on breakdown damage.

  17. Price performance following stock's IPO in different price limit systems

    Science.gov (United States)

    Wu, Ting; Wang, Yue; Li, Ming-Xia

    2018-01-01

    An IPO burst occurred in China's stock markets in 2015, while price limit trading rules usually help to reduce the short-term trading mania on individual stocks. It is interesting to make clear the function of the price limits after IPOs. We firstly make a statistical analysis based on all the IPO stocks listed from 1990 to 2015. A high dependency exists between the activities in stock's IPO and various market environment. We also focus on the price dynamics in the first 40 trading days after the stock listed. We find that price limit system will delay the price movement, especially for the up-trend movements, which may lead to longer continuous price limit hits. Similar to our previous work, many results such as ;W; shape can be also observed in the future daily return after the price limit open. At last, we find most IPO measures show evident correlations with the following price limit hits. IPO stocks with lower first-day turnover and earning per share will be followed with a longer continuous price limit hits and lower future daily return under the newest trading rules, which give us a good way to estimate the occurrence of price limit hits and the following price dynamics. Our analysis provides a better understanding of the price dynamics after IPO events and offers potential practical values for investors.

  18. High performance operational limits of tokamak and helical systems

    International Nuclear Information System (INIS)

    Yamazaki, Kozo; Kikuchi, Mitsuru

    2003-01-01

    The plasma operational boundaries of tokamak and helical systems are surveyed and compared with each other. Global confinement scaling laws are similar and gyro-Bohm like, however, local transport process is different due to sawtooth oscillations in tokamaks and ripple transport loss in helical systems. As for stability limits, achievable tokamak beta is explained by ideal or resistive MHD theories. On the other hand, beta values obtained so far in helical system are beyond ideal Mercier mode limits. Density limits in tokamak are often related to the coupling between radiation collapse and disruptive MHD instabilities, but the slow radiation collapse is dominant in the helical system. The pulse length of both tokamak and helical systems is on the order of hours in small machines, and the longer-pulsed good-confinement plasma operations compatible with radiative divertors are anticipated in both systems in the future. (author)

  19. Benefits and limitations in the use of performance indicators

    International Nuclear Information System (INIS)

    Nobile, M.; Ceccantini, M.

    1990-01-01

    In the paper, some Caorso NPP performance indicators for 1982 through 1986 are shown according to the definition of the Institute of Nuclear Power Operations (INPO). The comparison of the Caorso NPP performance indicators with those of similar American plants stresses an analogous behaviour for all the indicators but two: (Industrial Safety Lost-Time Accident Rate and Diesel Generator Unavailability), for which there is a very significant difference. A subsequent analysis enhances, however, that this difference cannot be attributed to component performance or personnel management politics, but essentially to design choices and/or to peculiar social and economical context; if these factors are taken into consideration, the difference between the performance indicators of the Caorso plant and those of American plants is explained quite satisfactorily. This demonstrates, that even if the usefulness of the performance indicators is confirmed, a careful analysis of all the possible implications is necessary before reaching any final conclusion

  20. Peaking for optimal performance: Research limitations and future directions.

    Science.gov (United States)

    Pyne, David B; Mujika, Iñigo; Reilly, Thomas

    2009-02-01

    A key element of the physical preparation of athletes is the taper period in the weeks immediately preceding competition. Existing research has defined the taper, identified various forms used in contemporary sport, and examined the prescription of training volume, load, intensity, duration, and type (progressive or step). Current limitations include: the lack of studies on team, combative, racquet, and precision (target) sports; the relatively small number of randomized controlled trials; the narrow focus on a single competition (single peak) compared with multiple peaking for weekly, multi-day or multiple events; and limited understanding of the physiological, neuromuscular, and biomechanical basis of the taper. Future research should address these limitations, together with the influence of prior training on optimal tapering strategies, and the interactions between the taper and long-haul travel, heat, and altitude. Practitioners seek information on how to prescribe tapers from season to season during an athlete's career, or a team's progression through a domestic league season, or multi-year Olympic or World Cup cycle. Practical guidelines for planning effective tapers for the Vancouver 2010 and London 2012 Olympics will evolve from both experimental investigations and modelling of successful tapers currently employed in a wide range of sports.

  1. RESURF power semiconductor devices - Performance and operating limits

    NARCIS (Netherlands)

    Ferrara, A.

    2016-01-01

    Power transmission is the transfer of energy from a generating source to a load which uses the energy to perform useful work. Since the end of the 19th century, electrical power transmission has replaced mechanical power transmission in all long distance applications. The alternating current (AC)

  2. RESURF power semiconductor devices: performance and operating limits

    NARCIS (Netherlands)

    Ferrara, A.

    2016-01-01

    Power transmission is the transfer of energy from a generating source to a load which uses the energy to perform useful work. Since the end of the 19th century, electrical power transmission has replaced mechanical power transmission in all long distance applications. The alternating current (AC)

  3. Capacitor performance limitations in high power converter applications

    DEFF Research Database (Denmark)

    El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

    2013-01-01

    High voltage low inductance capacitors are used in converters as HVDC-links, snubber circuits and sub model (MMC) capacitances. They facilitate the possibility of large peak currents under high frequent or transient voltage applications. On the other hand, using capacitors with larger equivalent...... series inductances include the risk of transient overvoltages, with a negative effect on life time and reliability of the capacitors. These allowable limits of such current and voltage peaks are decided by the ability of the converter components, including the capacitors, to withstand them over...... the expected life time. In this paper results are described from investigations on the electrical environment of these capacitors, including all the conditions they would be exposed to, thereby trying to find the tradeoffs needed to find a suitable capacitor. Different types of capacitors with the same voltage...

  4. Latent Factors Limiting the Performance of sEMG-Interfaces

    Directory of Open Access Journals (Sweden)

    Sergey Lobov

    2018-04-01

    Full Text Available Recent advances in recording and real-time analysis of surface electromyographic signals (sEMG have fostered the use of sEMG human–machine interfaces for controlling personal computers, prostheses of upper limbs, and exoskeletons among others. Despite a relatively high mean performance, sEMG-interfaces still exhibit strong variance in the fidelity of gesture recognition among different users. Here, we systematically study the latent factors determining the performance of sEMG-interfaces in synthetic tests and in an arcade game. We show that the degree of muscle cooperation and the amount of the body fatty tissue are the decisive factors in synthetic tests. Our data suggest that these factors can only be adjusted by long-term training, which promotes fine-tuning of low-level neural circuits driving the muscles. Short-term training has no effect on synthetic tests, but significantly increases the game scoring. This implies that it works at a higher decision-making level, not relevant for synthetic gestures. We propose a procedure that enables quantification of the gestures’ fidelity in a dynamic gaming environment. For each individual subject, the approach allows identifying “problematic” gestures that decrease gaming performance. This information can be used for optimizing the training strategy and for adapting the signal processing algorithms to individual users, which could be a way for a qualitative leap in the development of future sEMG-interfaces.

  5. Limitations imposed by wearing armour on Medieval soldiers' locomotor performance.

    Science.gov (United States)

    Askew, Graham N; Formenti, Federico; Minetti, Alberto E

    2012-02-22

    In Medieval Europe, soldiers wore steel plate armour for protection during warfare. Armour design reflected a trade-off between protection and mobility it offered the wearer. By the fifteenth century, a typical suit of field armour weighed between 30 and 50 kg and was distributed over the entire body. How much wearing armour affected Medieval soldiers' locomotor energetics and biomechanics is unknown. We investigated the mechanics and the energetic cost of locomotion in armour, and determined the effects on physical performance. We found that the net cost of locomotion (C(met)) during armoured walking and running is much more energetically expensive than unloaded locomotion. C(met) for locomotion in armour was 2.1-2.3 times higher for walking, and 1.9 times higher for running when compared with C(met) for unloaded locomotion at the same speed. An important component of the increased energy use results from the extra force that must be generated to support the additional mass. However, the energetic cost of locomotion in armour was also much higher than equivalent trunk loading. This additional cost is mostly explained by the increased energy required to swing the limbs and impaired breathing. Our findings can predict age-associated decline in Medieval soldiers' physical performance, and have potential implications in understanding the outcomes of past European military battles.

  6. Piezoelectric PVDF materials performance and operation limits in space environments

    International Nuclear Information System (INIS)

    Dargaville, Tim Richard; Assink, Roger Alan; Clough, Roger Lee; Celina, Mathias Christopher

    2004-01-01

    Piezoelectric polymers based on polyvinylidene fluoride (PVDF) are of interest for large aperture space-based telescopes. Dimensional adjustments of adaptive polymer films are achieved via charge deposition and require a detailed understanding of the piezoelectric material responses which are expected to suffer due to strong vacuum UV, gamma, X-ray, energetic particles and atomic oxygen under low earth orbit exposure conditions. The degradation of PVDF and its copolymers under various stress environments has been investigated. Initial radiation aging studies using gamma- and e-beam irradiation have shown complex material changes with significant crosslinking, lowered melting and Curie points (where observable), effects on crystallinity, but little influence on overall piezoelectric properties. Surprisingly, complex aging processes have also been observed in elevated temperature environments with annealing phenomena and cyclic stresses resulting in thermal depoling of domains. Overall materials performance appears to be governed by a combination of chemical and physical degradation processes. Molecular changes are primarily induced via radiative damage, and physical damage from temperature and AO exposure is evident as depoling and surface erosion. Major differences between individual copolymers have been observed providing feedback on material selection strategies

  7. Children's selective trust decisions: rational competence and limiting performance factors.

    Science.gov (United States)

    Hermes, Jonas; Behne, Tanya; Bich, Anna Elisa; Thielert, Christa; Rakoczy, Hannes

    2018-03-01

    Recent research has amply documented that even preschoolers learn selectively from others, preferring, for example, reliable over unreliable and competent over incompetent models. It remains unclear, however, what the cognitive foundations of such selective learning are, in particular, whether it builds on rational inferences or on less sophisticated processes. The current study, therefore, was designed to test directly the possibility that children are in principle capable of selective learning based on rational inference, yet revert to simpler strategies such as global impression formation under certain circumstances. Preschoolers (N = 75) were shown pairs of models that either differed in their degree of competence within one domain (strong vs. weak or knowledgeable vs. ignorant) or were both highly competent, but in different domains (e.g., strong vs. knowledgeable model). In the test trials, children chose between the models for strength- or knowledge-related tasks. The results suggest that, in fact, children are capable of rational inference-based selective trust: when both models were highly competent, children preferred the model with the competence most predictive and relevant for a given task. However, when choosing between two models that differed in competence on one dimension, children reverted to halo-style wide generalizations and preferred the competent models for both relevant and irrelevant tasks. These findings suggest that the rational strategies for selective learning, that children master in principle, can get masked by various performance factors. © 2017 John Wiley & Sons Ltd.

  8. Imaging performance of annular apertures. VI - Limitations by optical surface deviations

    Science.gov (United States)

    Tschunko, Hubert F. A.

    1987-01-01

    The performance of optical systems is limited by imperfect optical surfaces that degrade the images below the level set by wave theoretical limits. The central irradiance functions are derived for slit and circular apertures with five distributions of wavefront errors and for a range of maximal wavefront deviations. For practical frequency of occurrence distributions of wavefront deviations, the point spread and the image energy integral functions are determined. Practical performances of optical systems are derived and performance limits discussed.

  9. 14 CFR 135.399 - Small nontransport category airplane performance operating limitations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Small nontransport category airplane... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.399 Small nontransport category airplane performance operating limitations. (a) No person may operate a reciprocating engine or...

  10. 14 CFR 135.397 - Small transport category airplane performance operating limitations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Small transport category airplane... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.397 Small transport category airplane performance operating limitations. (a) No person may operate a reciprocating engine...

  11. Volumetric activity of SRS mixed waste and comparison with SRS performance and commercial facility limits

    International Nuclear Information System (INIS)

    Ades, M.J.; Daugherty, B.A.; Cook, J.R.

    1996-01-01

    This paper discusses the comparative analysis performed to estimate the after-treatment volumetric activity of the radionuclides included in the Savannah River site (SRS) mixed-waste streams and its comparison with the following: (1) The performance evaluation (PE) limits established for each radionuclide for on-site disposal: These limits correspond to the permissible waste disposal limits that are the lowest limits evaluated for the most restrictive release scenarios that include the groundwater pathway, the atmospheric pathway, and the intruder scenarios. (2) The radiological performance assessment (PA) limits established for each radionuclide for disposal in the SRS disposal vaults that meet the requirements of Chap. III of the U.S. Department of Energy Order 5820.2A: The vaults considered are the low-activity waste (LAW) vaults, the intermediate-level non-tritium (ILNT) vaults. and the intermediate-level tritium (ILT) vaults. (3) The radioactive limits of a commercial mixed waste disposal facility

  12. High Performance Redox Flow Batteries: An Analysis of the Upper Performance Limits of Flow Batteries Using Non-aqueous Solvents

    International Nuclear Information System (INIS)

    Sun, C.-N.; Mench, M.M.; Zawodzinski, T.A.

    2017-01-01

    Redox Flow Batteries (RFBs) are a promising technology for grid-scale electrochemical energy storage. In this work, we use a recently achieved high-performance flow battery performance curve as a basis to assess the maximum achievable performance of a RFB employing non-aqueous solutions as active materials. First we show high performance in a vanadium redox flow battery (VRFB), specifically a limiting situation in which the cell losses are ohmic in nature and derive from electrolyte conductance. Based on that case, we analyze the analogous limiting behavior of non-aqueous (NA) systems using a series of calculations assuming similar ohmic losses, scaled by the relative electrolyte resistances, with a higher voltage redox couple assumed for the NA battery. The results indicate that the NA battery performance is limited by the low electrolyte conductivity to a fraction of the performance of the VRFB. Given the narrow window in which the NARFB offers advantages, even for the most generous limiting assumptions related to performance while ignoring the numerous other disadvantageous aspects of these systems, we conclude that this technology is unlikely under present circumstances to provide practical large-scale energy storage solutions.

  13. Towards integrating control and information theories from information-theoretic measures to control performance limitations

    CERN Document Server

    Fang, Song; Ishii, Hideaki

    2017-01-01

    This book investigates the performance limitation issues in networked feedback systems. The fact that networked feedback systems consist of control and communication devices and systems calls for the integration of control theory and information theory. The primary contributions of this book lie in two aspects: the newly-proposed information-theoretic measures and the newly-discovered control performance limitations. We first propose a number of information notions to facilitate the analysis. Using those notions, classes of performance limitations of networked feedback systems, as well as state estimation systems, are then investigated. In general, the book presents a unique, cohesive treatment of performance limitation issues of networked feedback systems via an information-theoretic approach. This book is believed to be the first to treat the aforementioned subjects systematically and in a unified manner, offering a unique perspective differing from existing books.

  14. Performance Limiting Effects in Power Generation from Salinity Gradients by Pressure Retarded Osmosis

    KAUST Repository

    Yip, Ngai Yin; Elimelech, Menachem

    2011-01-01

    Pressure retarded osmosis has the potential to utilize the free energy of mixing when fresh river water flows into the sea for clean and renewable power generation. Here, we present a systematic investigation of the performance limiting phenomena

  15. Performance limits of direct cryogenically cooled silicon monochromators - experimental results at the APS

    International Nuclear Information System (INIS)

    Lee, W.-K.; Fernandez, P.; Mills, D.M.

    2000-01-01

    The successful use of cryogenically cooled silicon monochromators at third-generation synchrotron facilities is well documented. At the Advanced Photon Source (APS) it has been shown that, at 100 mA operation with the standard APS undulator A, the cryogenically cooled silicon monochromator performs very well with minimal (<2 arcsec) or no observable thermal distortions. However, to date there has not been any systematic experimental study on the performance limits of this approach. This paper presents experimental results on the performance limits of these directly cooled crystals. The results show that if the beam is limited to the size of the radiation central cone then, at the APS, the crystal will still perform well at twice the present 100 mA single 2.4 m-long 3.3 cm-period undulator heat load. However, the performance would degrade rapidly if a much larger incident white-beam size is utilized

  16. Treating Chronically Ill Diabetic Patients with Limited Life Expectancy: Implications for Performance Measurement

    Science.gov (United States)

    Woodard, LeChauncy D.; Landrum, Cassie R.; Urech, Tracy H.; Profit, Jochen; Virani, Salim S.; Petersen, Laura A.

    2012-01-01

    Background/Objectives To validly assess quality-of-care differences among providers, performance measurement programs must reliably identify and exclude patients for whom the quality indicator may not be desirable, including those with limited life expectancy. We developed an algorithm to identify patients with limited life expectancy and examined the impact of limited life expectancy on glycemic control and treatment intensification among diabetic patients. Design We identified diabetic patients with coexisting congestive heart failure, chronic obstructive pulmonary disease, dementia, end-stage liver disease, and/or primary/metastatic cancers with limited life expectancy. To validate our algorithm, we assessed 5-year mortality among patients identified as having limited life expectancy. We compared rates of meeting performance measures for glycemic control between patients with and without limited life expectancy. Among uncontrolled patients, we examined the impact of limited life expectancy on treatment intensification within 90 days. Setting 110 Veterans Administration facilities; October 2006 – September 2007 Participants 888,628 diabetic patients Measurements Hemoglobin A1c (HbA1c) Quality measurement and performance-based reimbursement systems should acknowledge the different needs of this population. PMID:22260627

  17. Targeting Allostery with Avatars to Design Inhibitors Assessed by Cell Activity: Dissecting MRE11 Endo- and Exonuclease Activities.

    Science.gov (United States)

    Moiani, Davide; Ronato, Daryl A; Brosey, Chris A; Arvai, Andrew S; Syed, Aleem; Masson, Jean-Yves; Petricci, Elena; Tainer, John A

    2018-01-01

    For inhibitor design, as in most research, the best system is question dependent. We suggest structurally defined allostery to design specific inhibitors that target regions beyond active sites. We choose systems allowing efficient quality structures with conformational changes as optimal for structure-based design to optimize inhibitors. We maintain that evolutionarily related targets logically provide molecular avatars, where this Sanskrit term for descent includes ideas of functional relationships and of being a physical embodiment of the target's essential features without requiring high sequence identity. Appropriate biochemical and cell assays provide quantitative measurements, and for biomedical impacts, any inhibitor's activity should be validated in human cells. Specificity is effectively shown empirically by testing if mutations blocking target activity remove cellular inhibitor impact. We propose this approach to be superior to experiments testing for lack of cross-reactivity among possible related enzymes, which is a challenging negative experiment. As an exemplary avatar system for protein and DNA allosteric conformational controls, we focus here on developing separation-of-function inhibitors for meiotic recombination 11 nuclease activities. This was achieved not by targeting the active site but rather by geometrically impacting loop motifs analogously to ribosome antibiotics. These loops are neighboring the dimer interface and active site act in sculpting dsDNA and ssDNA into catalytically competent complexes. One of our design constraints is to preserve DNA substrate binding to geometrically block competing enzymes and pathways from the damaged site. We validate our allosteric approach to controlling outcomes in human cells by reversing the radiation sensitivity and genomic instability in BRCA mutant cells. © 2018 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Antoine, Claire Z

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Antoine, Claire Z [IRFU, Saclay (France)

    2014-07-01

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

  20. Performance limits for exo-clutter Ground Moving Target Indicator (GMTI) radar.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2010-09-01

    The performance of a Ground Moving Target Indicator (GMTI) radar system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to 'get your arms around' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall GMTI radar system. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the 'seek time'.

  1. Improving the performance of power-limited transverse stochastic cooling systems

    International Nuclear Information System (INIS)

    Goldberg, D.A.; Lambertson, G.R.

    1989-08-01

    We present the formulas relevant to the behavior of (transverse) stochastic cooling systems which operate under the not uncommon condition that performance is limited by available output power, and contrast the operation of such systems with non-power-limited ones. In particular, we show that for power-limited systems, the two most effective improvements are the use of pickups/kickers which operate in both planes simultaneously and/or plunging of the cooling system electrodes, and present an example where increasing bandwidth is counter-productive. We apply our results to the proposed upgrade of the Fermilab bar p source. 4 refs., 1 fig., 2 tabs

  2. The Effect of Modified Control Limits on the Performance of a Generic Commercial Aircraft Engine

    Science.gov (United States)

    Csank, Jeffrey T.; May, Ryan D.; Gou, Ten-Huei; Litt, Jonathan S.

    2012-01-01

    This paper studies the effect of modifying the control limits of an aircraft engine to obtain additional performance. In an emergency situation, the ability to operate an engine above its normal operating limits and thereby gain additional performance may aid in the recovery of a distressed aircraft. However, the modification of an engine s limits is complex due to the risk of an engine failure. This paper focuses on the tradeoff between enhanced performance and risk of either incurring a mechanical engine failure or compromising engine operability. The ultimate goal is to increase the engine performance, without a large increase in risk of an engine failure, in order to increase the probability of recovering the distressed aircraft. The control limit modifications proposed are to extend the rotor speeds, temperatures, and pressures to allow more thrust to be produced by the engine, or to increase the rotor accelerations and allow the engine to follow a fast transient. These modifications do result in increased performance; however this study indicates that these modifications also lead to an increased risk of engine failure.

  3. Testing the Limits of Optimizing Dual-Task Performance in Younger and Older Adults

    Science.gov (United States)

    Strobach, Tilo; Frensch, Peter; Müller, Herrmann Josef; Schubert, Torsten

    2012-01-01

    Impaired dual-task performance in younger and older adults can be improved with practice. Optimal conditions even allow for a (near) elimination of this impairment in younger adults. However, it is unknown whether such (near) elimination is the limit of performance improvements in older adults. The present study tests this limit in older adults under conditions of (a) a high amount of dual-task training and (b) training with simplified component tasks in dual-task situations. The data showed that a high amount of dual-task training in older adults provided no evidence for an improvement of dual-task performance to the optimal dual-task performance level achieved by younger adults. However, training with simplified component tasks in dual-task situations exclusively in older adults provided a similar level of optimal dual-task performance in both age groups. Therefore through applying a testing the limits approach, we demonstrated that older adults improved dual-task performance to the same level as younger adults at the end of training under very specific conditions. PMID:22408613

  4. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    International Nuclear Information System (INIS)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Karatzas, L S

    2009-01-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  5. Nanocomposites of graphene oxide and upconversion rare-earth nanocrystals with superior optical limiting performance

    KAUST Repository

    Wei, Wei; He, Tingchao; Teng, Xue; Wu, Shixin; Ma, Lin; Zhang, Hua; Ma, Jan; Yang, Yanhui; Chen, Hongyu; Han, Yu; Sun, Handong; Huang, Ling

    2012-01-01

    ), show excellent performance in optical limiting (OL); however, the wavelengths of currently used lasers for OL studies mainly focus on either 532 or 1064 nm. To design new-generation OL materials working at other optical regions, such as the NIR, a novel

  6. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    Energy Technology Data Exchange (ETDEWEB)

    Hadjiloucas, S; Walker, G C; Bowen, J W [Cybernetics, School of Systems Engineering, University of Reading, RG6 6AY (United Kingdom); Karatzas, L S, E-mail: s.hadjiloucas@reading.ac.u [Temasek Polytechnic, School of Engineering, 21 Tampines Avenue 1, Singapore, 529757 (Singapore)

    2009-07-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  7. Performance of an irreversible quantum Ericsson cooler at low temperature limit

    International Nuclear Information System (INIS)

    Wu Feng; Chen Lingen; Wu Shuang; Sun Fengrui

    2006-01-01

    The purpose of this paper is to investigate the effect of quantum properties of the working medium on the performance of an irreversible quantum Ericsson cooler with spin-1/2. The cooler is studied with the losses of heat resistance, heat leakage and internal irreversibility. The optimal relationship between the dimensionless cooling load R * versus the coefficient of performance ε for the irreversible quantum Ericsson cooler is derived. In particular, the performance characteristics of the cooler at the low temperature limit are discussed

  8. Performance Limiting Effects in Power Generation from Salinity Gradients by Pressure Retarded Osmosis

    KAUST Repository

    Yip, Ngai Yin

    2011-12-01

    Pressure retarded osmosis has the potential to utilize the free energy of mixing when fresh river water flows into the sea for clean and renewable power generation. Here, we present a systematic investigation of the performance limiting phenomena in pressure retarded osmosis-external concentration polarization, internal concentration polarization, and reverse draw salt flux-and offer insights on the design criteria of a high performance pressure retarded osmosis power generation system. Thin-film composite polyamide membranes were chemically modified to produce a range of membrane transport properties, and the water and salt permeabilities were characterized to determine the underlying permeability-selectivity trade-off relationship. We show that power density is constrained by the trade-off between permeability and selectivity of the membrane active layer. This behavior is attributed to the opposing influence of the beneficial effect of membrane water permeability and the detrimental impact of reverse salt flux coupled with internal concentration polarization. Our analysis reveals the intricate influence of active and support layer properties on power density and demonstrates that membrane performance is maximized by tailoring the water and salt permeabilities to the structural parameters. An analytical parameter that quantifies the relative influence of each performance limiting phenomena is employed to identify the dominant effect restricting productivity. External concentration polarization is shown to be the main factor limiting performance at high power densities. Enhancement of the hydrodynamic flow conditions in the membrane feed channel reduces external concentration polarization and thus, yields improved power density. However, doing so will also incur additional operating costs due to the accompanying hydraulic pressure loss. This study demonstrates that by thoughtful selection of the membrane properties and hydrodynamic conditions, the detrimental

  9. Follow-up skeletal surveys for nonaccidental trauma: can a more limited survey be performed?

    Energy Technology Data Exchange (ETDEWEB)

    Harlan, Susan R. [University of Utah School of Medicine, Department of Radiology, Salt Lake City, UT (United States); Nixon, G.W.; Prince, Jeffrey S. [Primary Children' s Medical Center, Department of Medical Imaging, Salt Lake City, UT (United States); Campbell, Kristine A.; Hansen, Karen [University of Utah School of Medicine, Department of Pediatrics, Salt Lake City, UT (United States)

    2009-09-15

    Studies have demonstrated the value of the follow-up skeletal survey in identifying additional fractures, clarifying indeterminate findings, and improving dating of skeletal injuries in victims of physical abuse. To determine whether a more limited follow-up survey could yield the same radiologic data as a full follow-up survey. The study cohort comprised 101 children who had follow-up surveys that met our inclusion criteria. Consensus readings of both original and follow-up surveys were performed by two pediatric radiologists. These results were compared to determine additional findings from the follow-up surveys. Limited skeletal survey protocols were evaluated to determine whether they would detect the same fractures seen with a complete osseous survey. In the 101 children 244 fractures were identified on the initial osseous survey. Follow-up surveys demonstrated new information in 38 children (37.6%). A 15-view limited follow-up survey identified all additional information seen on the complete follow-up survey. Our data demonstrate that a 15-view limited follow-up skeletal survey could be performed without missing clinically significant new fractures and still allow proper identification of confirmed fractures or normal findings. A limited survey would decrease radiation dose in children. (orig.)

  10. Follow-up skeletal surveys for nonaccidental trauma: can a more limited survey be performed?

    International Nuclear Information System (INIS)

    Harlan, Susan R.; Nixon, G.W.; Prince, Jeffrey S.; Campbell, Kristine A.; Hansen, Karen

    2009-01-01

    Studies have demonstrated the value of the follow-up skeletal survey in identifying additional fractures, clarifying indeterminate findings, and improving dating of skeletal injuries in victims of physical abuse. To determine whether a more limited follow-up survey could yield the same radiologic data as a full follow-up survey. The study cohort comprised 101 children who had follow-up surveys that met our inclusion criteria. Consensus readings of both original and follow-up surveys were performed by two pediatric radiologists. These results were compared to determine additional findings from the follow-up surveys. Limited skeletal survey protocols were evaluated to determine whether they would detect the same fractures seen with a complete osseous survey. In the 101 children 244 fractures were identified on the initial osseous survey. Follow-up surveys demonstrated new information in 38 children (37.6%). A 15-view limited follow-up survey identified all additional information seen on the complete follow-up survey. Our data demonstrate that a 15-view limited follow-up skeletal survey could be performed without missing clinically significant new fractures and still allow proper identification of confirmed fractures or normal findings. A limited survey would decrease radiation dose in children. (orig.)

  11. Evaluation on current-limiting performance of the YBCO thin-film wire considering electric coupling condition

    International Nuclear Information System (INIS)

    Du, H.-I.; Han, B.-S.; Kim, Y.-J.; Lee, D.-H.; Song, S.-S.; Han, T.-H.; Han, S.-C.

    2011-01-01

    The basic way to improve the performance of a superconducting current limiter is to apply and evaluate a superconducting device that is appropriate to the superconducting current limiter. Among the many types of superconducting devices, the YBCO thin film wire has excellent current-limiting performance that is appropriate for actual system application. For the application of the YBCO thin film wire to superconducting current limiters, its current-limiting performance as a unit device must be accurately evaluated, and measures to improve its current-limiting performance must be sought. Accordingly, to evaluate the current-limiting performance of the YBCO thin film wire, this study was conducted to evaluate its resistance-increasing trend, V max , T r , I max , I qt , and current-limiting rate as a unit device, after which the electric coupling condition that consists of a core and windings was used to evaluate the current-limiting performance of the YBCO thin film wire.

  12. What Limits Cardiac Performance during Exercise in Normal Subjects and in Healthy Fontan Patients?

    Directory of Open Access Journals (Sweden)

    André La Gerche

    2010-01-01

    Full Text Available Exercise is an important determinant of health but is significantly reduced in the patient with a univentricular circulation. Normal exercise physiology mandates an increase in pulmonary artery pressures which places an increased work demand on the right ventricle (RV. In a biventricular circulation with pathological increases in pulmonary vascular resistance and/or reductions in RV function, exercise-induced augmentation of cardiac output is limited. Left ventricular preload reserve is dependent upon flow through the pulmonary circulation and this requires adequate RV performance. In the Fontan patient, the reasons for exercise intolerance are complex. In those patients with myocardial dysfunction or other pathologies of the circulatory components, it is likely that these abnormalities serve as a limitation to cardiac performance during exercise. However, in the healthy Fontan patient, it may be the absence of a sub-pulmonary pump which limits normal increases in pulmonary pressures, trans-pulmonary flow requirements and cardiac output. If so, performance will be exquisitely dependent on pulmonary vascular resistance. This provides a potential explanation as to why pulmonary vasodilators may improve exercise tolerance. As has recently been demonstrated, these agents may offer an important new treatment strategy which directly addresses the physiological limitations in the Fontan patient.

  13. Design of coated standing nanowire array solar cell performing beyond the planar efficiency limits

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yang; Ye, Qinghao; Shen, Wenzhong, E-mail: wzshen@sjtu.edu.cn [Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-05-28

    The single standing nanowire (SNW) solar cells have been proven to perform beyond the planar efficiency limits in both open-circuit voltage and internal quantum efficiency due to the built-in concentration and the shifting of the absorption front. However, the expandability of these nano-scale units to a macro-scale photovoltaic device remains unsolved. The main difficulty lies in the simultaneous preservation of an effective built-in concentration in each unit cell and a broadband high absorption capability of their array. Here, we have provided a detailed theoretical guideline for realizing a macro-scale solar cell that performs furthest beyond the planar limits. The key lies in a complementary design between the light-trapping of the single SNWs and that of the photonic crystal slab formed by the array. By tuning the hybrid HE modes of the SNWs through the thickness of a coaxial dielectric coating, the optimized coated SNW array can sustain an absorption rate over 97.5% for a period as large as 425 nm, which, together with the inherited carrier extraction advantage, leads to a cell efficiency increment of 30% over the planar limit. This work has demonstrated the viability of a large-size solar cell that performs beyond the planar limits.

  14. Impact of power limitations on the performance of WLANs for home networking applications

    OpenAIRE

    Armour, SMD; Lee, BS; Doufexi, A; Nix, AR; Bull, DR

    2001-01-01

    This paper considers the application of 5 GHz wireless LAN technology to home networking applications. An assessment of physical layer performance is presented in the form of the achievable data rate as a function of received signal to noise ratio. The transmit power limitations imposed by the relevant regulatory bodies are also summarised. Based on this information, a state of the art propagation modelling tool is used to evaluate the coverage achieved by a WLAN system in an example resident...

  15. A general method for assessing brain-computer interface performance and its limitations

    Science.gov (United States)

    Hill, N. Jeremy; Häuser, Ann-Katrin; Schalk, Gerwin

    2014-04-01

    Objective. When researchers evaluate brain-computer interface (BCI) systems, we want quantitative answers to questions such as: How good is the system’s performance? How good does it need to be? and: Is it capable of reaching the desired level in future? In response to the current lack of objective, quantitative, study-independent approaches, we introduce methods that help to address such questions. We identified three challenges: (I) the need for efficient measurement techniques that adapt rapidly and reliably to capture a wide range of performance levels; (II) the need to express results in a way that allows comparison between similar but non-identical tasks; (III) the need to measure the extent to which certain components of a BCI system (e.g. the signal processing pipeline) not only support BCI performance, but also potentially restrict the maximum level it can reach. Approach. For challenge (I), we developed an automatic staircase method that adjusted task difficulty adaptively along a single abstract axis. For challenge (II), we used the rate of information gain between two Bernoulli distributions: one reflecting the observed success rate, the other reflecting chance performance estimated by a matched random-walk method. This measure includes Wolpaw’s information transfer rate as a special case, but addresses the latter’s limitations including its restriction to item-selection tasks. To validate our approach and address challenge (III), we compared four healthy subjects’ performance using an EEG-based BCI, a ‘Direct Controller’ (a high-performance hardware input device), and a ‘Pseudo-BCI Controller’ (the same input device, but with control signals processed by the BCI signal processing pipeline). Main results. Our results confirm the repeatability and validity of our measures, and indicate that our BCI signal processing pipeline reduced attainable performance by about 33% (21 bits min-1). Significance. Our approach provides a flexible basis

  16. Above the nominal limit performance evaluation of multiwavelength optical code-division multiple-access systems

    Science.gov (United States)

    Inaty, Elie; Raad, Robert; Fortier, Paul; Shalaby, Hossam M. H.

    2009-03-01

    We provide an analysis for the performance of a multiwavelength optical code-division multiple-access (MW-OCDMA) network when the system is working above the nominal transmission rate limit imposed by passive encoding-decoding operation. We address the problem of overlapping in such a system and how it can directly affect the bit error rate (BER). A unified mathematical framework is presented under the assumption of one-coincidence sequences with nonrepeating wavelengths. A closed form expression of the multiple access interference limited BER is provided as a function of different system parameters. Results show that the performance of the MW-OCDMA system can be critically affected when working above the nominal limit, an event that can happen when the network operates at a high transmission rate. In addition, the impact of the derived error probability on the performance of two newly proposed medium access control (MAC) protocols, the S-ALOHA and the R3T, is also investigated. It is shown that for low transmission rates, the S-ALOHA is better than the R3T, while the R3T is better at very high transmission rates. In general, it is postulated that the R3T protocol suffers a higher delay mainly because of the presence of additional modes.

  17. Effects of Heat of Vaporization and Octane Sensitivity on Knock-Limited Spark Ignition Engine Performance

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burton, Jonathan L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sindler, Petr [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McCormick, Robert L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Christensen, Earl D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fouts, Lisa A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-03

    Knock-limited loads for a set of surrogate gasolines all having nominal 100 research octane number (RON), approximately 11 octane sensitivity (S), and a heat of vaporization (HOV) range of 390 to 595 kJ/kg at 25 degrees C were investigated. A single-cylinder spark-ignition engine derived from a General Motors Ecotec direct injection (DI) engine was used to perform load sweeps at a fixed intake air temperature (IAT) of 50 degrees C, as well as knock-limited load measurements across a range of IATs up to 90 degrees C. Both DI and pre-vaporized fuel (supplied by a fuel injector mounted far upstream of the intake valves and heated intake runner walls) experiments were performed to separate the chemical and thermal effects of the fuels' knock resistance. The DI load sweeps at 50 degrees C intake air temperature showed no effect of HOV on the knock-limited performance. The data suggest that HOV acts as a thermal contributor to S under the conditions studied. Measurement of knock-limited loads from the IAT sweeps for DI at late combustion phasing showed that a 40 vol% ethanol (E40) blend provided additional knock resistance at the highest temperatures, compared to a 20 vol% ethanol blend and hydrocarbon fuel with similar RON and S. Using the pre-vaporized fuel system, all the high S fuels produced nearly identical knock-limited loads at each temperature across the range of IATs studied. For these fuels RON ranged from 99.2 to 101.1 and S ranged from 9.4 to 12.2, with E40 having the lowest RON and highest S. The higher knock-limited loads for E40 at the highest IATs examined were consistent with the slightly higher S for this fuel, and the lower engine operating condition K values arising from use of this fuel. The study highlights how fuel HOV can affect the temperature at intake valve closing, and consequently the pressure-temperature history of the end gas leading to more negative values of K, thereby enhancing the effect of S on knock resistance.

  18. Missing depth cues in virtual reality limit performance and quality of three dimensional reaching movements.

    Science.gov (United States)

    Gerig, Nicolas; Mayo, Johnathan; Baur, Kilian; Wittmann, Frieder; Riener, Robert; Wolf, Peter

    2018-01-01

    Goal-directed reaching for real-world objects by humans is enabled through visual depth cues. In virtual environments, the number and quality of available visual depth cues is limited, which may affect reaching performance and quality of reaching movements. We assessed three-dimensional reaching movements in five experimental groups each with ten healthy volunteers. Three groups used a two-dimensional computer screen and two groups used a head-mounted display. The first screen group received the typically recreated visual depth cues, such as aerial and linear perspective, occlusion, shadows, and texture gradients. The second screen group received an abstract minimal rendering lacking those. The third screen group received the cues of the first screen group and absolute depth cues enabled by retinal image size of a known object, which realized with visual renderings of the handheld device and a ghost handheld at the target location. The two head-mounted display groups received the same virtually recreated visual depth cues as the second or the third screen group respectively. Additionally, they could rely on stereopsis and motion parallax due to head-movements. All groups using the screen performed significantly worse than both groups using the head-mounted display in terms of completion time normalized by the straight-line distance to the target. Both groups using the head-mounted display achieved the optimal minimum in number of speed peaks and in hand path ratio, indicating that our subjects performed natural movements when using a head-mounted display. Virtually recreated visual depth cues had a minor impact on reaching performance. Only the screen group with rendered handhelds could outperform the other screen groups. Thus, if reaching performance in virtual environments is in the main scope of a study, we suggest applying a head-mounted display. Otherwise, when two-dimensional screens are used, achievable performance is likely limited by the reduced depth

  19. Optimizing the performance and structure of the D0 Collie confidence limit evaluator

    Energy Technology Data Exchange (ETDEWEB)

    Fishchler, Mark; /Fermilab

    2010-07-01

    D0 Collie is a program used to perform limit calculations based on ensembles of pseudo-experiments ('PEs'). Since the application of this program to the crucial Higgs mass limit is quite CPU intensive, it has been deemed important to carefully review this program, with an eye toward identifying and implementing potential performance improvements. At the same time, we identify any coding errors or opportunities for potential structural (or algorithm) improvement discovered in the course of gaining sufficient understanding of the workings of Collie to sensibly explore for optimizations. Based on a careful analysis of the program, a series of code changes with potential for improving performance has been identified. The implementation and evaluation of the most important parts of this series has been done, with gratifying speedup results. The bottom line: We have identified and implemented changes leading to a factor of 2.19 speedup in the example program provided, and expected to translate to a factor of roughly 4 speedup in typical realistic usage.

  20. Work Functioning Among Firefighters: A Comparison Between Self-Reported Limitations and Functional Task Performance.

    Science.gov (United States)

    MacDermid, Joy C; Tang, Kenneth; Sinden, Kathryn E; D'Amico, Robert

    2018-05-25

    Purpose Performance-based and disease indicators have been widely studied in firefighters; self-reported work role limitations have not. The aim of this study was to describe the distributions and correlations of a generic self-reported Work Limitations Questionnaire (WLQ-26) and firefighting-specific task performance-based tests. Methods Active firefighters from the City of Hamilton Fire Services (n = 293) were recruited. Participants completed the WLQ-26 to quantify on-the-job difficulties over five work domains: work scheduling (4 items), output demands (7 items), physical demands (8 items), mental demands (4 items), and social demands (3 items). A subset of participants (n = 149) were also assessed on hose drag and stair climb with a high-rise pack performance-based tests. Descriptive statistics and correlations were used to compare item/subscale performance; and to describe the inter-relationships between tests. Results The mean WLQ-26 item scores (/5) ranged from 4.1 to 4.4 (median = 5 for all items); most firefighters (54.5-80.5%) selected "difficult none of the time" response option on all items. A substantial ceiling effect was observed across all five WLQ-26 subscales as 44.0-55.6% were in the highest category. Subscale means ranged from 61.8 (social demands) to 78.7 (output demands and physical demands). Internal consistency exceeded 0.90 on all subscales. For the hose drag task, the mean time-to-completion was 48.0 s (SD = 14.5; range 20.4-95.0). For the stair climb task, the mean time-to-completion was 76.7 s (SD = 37.2; range 21.0-218.0). There were no significant correlations between self-report work limitations and performance of firefighting tasks. Conclusions The WLQ-26 measured five domains, but had ceiling effects in firefighters. Performance-based testing showed wider score range, lacked ceiling effects and did not correlate to the WLQ-26. A firefighter-specific, self-report role functioning scale may be needed to identify

  1. Prospects and performance limitations for Cu-Zn-Sn-S-Se photovoltaic technology.

    Science.gov (United States)

    Mitzi, David B; Gunawan, Oki; Todorov, Teodor K; Barkhouse, D Aaron R

    2013-08-13

    While cadmium telluride and copper-indium-gallium-sulfide-selenide (CIGSSe) solar cells have either already surpassed (for CdTe) or reached (for CIGSSe) the 1 GW yr⁻¹ production level, highlighting the promise of these rapidly growing thin-film technologies, reliance on the heavy metal cadmium and scarce elements indium and tellurium has prompted concern about scalability towards the terawatt level. Despite recent advances in structurally related copper-zinc-tin-sulfide-selenide (CZTSSe) absorbers, in which indium from CIGSSe is replaced with more plentiful and lower cost zinc and tin, there is still a sizeable performance gap between the kesterite CZTSSe and the more mature CdTe and CIGSSe technologies. This review will discuss recent progress in the CZTSSe field, especially focusing on a direct comparison with analogous higher performing CIGSSe to probe the performance bottlenecks in Earth-abundant kesterite devices. Key limitations in the current generation of CZTSSe devices include a shortfall in open circuit voltage relative to the absorber band gap and secondarily a high series resistance, which contributes to a lower device fill factor. Understanding and addressing these performance issues should yield closer performance parity between CZTSSe and CdTe/CIGSSe absorbers and hopefully facilitate a successful launch of commercialization for the kesterite-based technology.

  2. Adaptive Transmitter Optimization in Multiuser Multiantenna Systems: Theoretical Limits, Effect of Delays, and Performance Enhancements

    Directory of Open Access Journals (Sweden)

    Samardzija Dragan

    2005-01-01

    Full Text Available The advances in programmable and reconfigurable radios have rendered feasible transmitter optimization schemes that can greatly improve the performance of multiple-antenna multiuser systems. Reconfigurable radio platforms are particularly suitable for implementation of transmitter optimization at the base station. We consider the downlink of a wireless system with multiple transmit antennas at the base station and a number of mobile terminals (i.e., users each with a single receive antenna. Under an average transmit power constraint, we consider the maximum achievable sum data rates in the case of (1 zero-forcing (ZF spatial prefilter, (2 modified zero-forcing (MZF spatial prefilter, and (3 triangularization spatial prefilter coupled with dirty-paper coding (DPC transmission scheme. We show that the triangularization with DPC approaches the closed-loop MIMO rates (upper bound for higher SNRs. Further, the MZF solution performs very well for lower SNRs, while for higher SNRs, the rates for the ZF solution converge to the MZF rates. An important impediment that degrades the performance of such transmitter optimization schemes is the delay in channel state information (CSI. We characterize the fundamental limits of performance in the presence of delayed CSI and then propose performance enhancements using a linear MMSE predictor of the CSI that can be used in conjunction with transmitter optimization in multiple-antenna multiuser systems.

  3. Limitation for performance of jobs in power unit control room of nuclear power plant

    International Nuclear Information System (INIS)

    Janas, D.

    1988-01-01

    The procedure is described for an analysis of the somatic and mental health condition of operating personnel in the unit control room of a nuclear power plant. It was divided into three stages, viz.: (1) determination of adverse and favorable effects of work; (2) the recording of social, psychological, physiological and biochemical changes in the personnel; (3) determination of possibilities of controlling the limit for performance of a job. The analysis showed that the problem is complex and should permanently remain in the centre of attention. (J.B.). 3 refs

  4. Performance of intact and partially degraded concrete barriers in limiting mass transport

    International Nuclear Information System (INIS)

    Walton, J.C.

    1992-06-01

    Mass transport through concrete barriers and release rate from concrete vaults are quantitatively evaluated. The thorny issue of appropriate diffusion coefficients for use in performance assessment calculations is covered, with no ultimate solution found. Release from monolithic concrete vaults composed of concrete waste forms is estimated with a semi-analytical solution. A parametric study illustrates the importance of different parameters on release. A second situation of importance is the role of a concrete shell or vault placed around typical waste forms in limiting mass transport. In both situations, the primary factor controlling concrete performance is cracks. The implications of leaching behavior on likely groundwater concentrations is examined. Frequently, lower groundwater concentrations can be expected in the absence of engineered covers that reduce infiltration

  5. RELATIONSHIP BETWEEN FUNCTIONAL LIMITATIONS OF THE LOCOMOTOR SYSTEM AND PERFORMANCE IN JUDO

    Directory of Open Access Journals (Sweden)

    Boguszewski Dariusz

    2017-09-01

    Full Text Available Introduction. The high demands imposed by judo with regard to physical fitness can predispose athletes practising this sport to injury. The aim of the current study was to determine the relationship between the degree of functional limitations and performance outcomes in judo athletes. Material and methods. The study involved 23 judo athletes aged 17-27 years. For the purpose of carrying out comparative analyses, the judokas were divided into two groups according to their level of achievement. The first group consisted of medallists in international tournaments and Polish championships, and the second group was composed of non-medallists. The research tool used was the Functional Movement Screen test battery, which included seven exercise tests whose performance was rated on a scale from 0 to 3. Relationships between variables were assessed using Spearman’s rho correlation coefficients. Inter-group differences were determined by means of the Mann-Whitney U test, and differences between the left and right side of the body in bilateral tests were examined using the Wilcoxon test (statistical significance was set at p ≤ 0.05. Results. The total score for the FMS test was significantly higher (p < 0.05 in judo athletes who had a higher level of achievement. Scores below 14 points, which were indicative of high susceptibility to injury, were received by two athletes from the group of medallists and 8 non-medallists. Major asymmetries were not found in the subjects; significant differences were observed only in the shoulder mobility test in senior judokas (p < 0.05 and non-medallists (p < 0.01. Conclusions. Judo athletes who had better performance outcomes in competitions had higher scores in the FMS test. Functional limitations can have an impact on the outcomes of performance in judo; their degree is indicative of the quality of the movement as well as of susceptibility to injury.

  6. Nogo receptor 1 limits tactile task performance independent of basal anatomical plasticity.

    Directory of Open Access Journals (Sweden)

    Jennifer I Park

    Full Text Available The genes that govern how experience refines neural circuitry and alters synaptic structural plasticity are poorly understood. The nogo-66 receptor 1 gene (ngr1 is one candidate that may restrict the rate of learning as well as basal anatomical plasticity in adult cerebral cortex. To investigate if ngr1 limits the rate of learning we tested adult ngr1 null mice on a tactile learning task. Ngr1 mutants display greater overall performance despite a normal rate of improvement on the gap-cross assay, a whisker-dependent learning paradigm. To determine if ngr1 restricts basal anatomical plasticity in the associated sensory cortex, we repeatedly imaged dendritic spines and axonal varicosities of both constitutive and conditional adult ngr1 mutant mice in somatosensory barrel cortex for two weeks through cranial windows with two-photon chronic in vivo imaging. Neither constant nor acute deletion of ngr1 affected turnover or stability of dendritic spines or axonal boutons. The improved performance on the gap-cross task is not attributable to greater motor coordination, as ngr1 mutant mice possess a mild deficit in overall performance and a normal learning rate on the rotarod, a motor task. Mice lacking ngr1 also exhibit normal induction of tone-associated fear conditioning yet accelerated fear extinction and impaired consolidation. Thus, ngr1 alters tactile and motor task performance but does not appear to limit the rate of tactile or motor learning, nor determine the low set point for synaptic turnover in sensory cortex.

  7. A systematic review of the sleep, sleepiness, and performance implications of limited wake shift work schedules.

    Science.gov (United States)

    Short, Michelle A; Agostini, Alexandra; Lushington, Kurt; Dorrian, Jillian

    2015-09-01

    The aim of this review was to identify which limited wake shift work schedules (LWSW) best promote sleep, alertness, and performance. LWSW are fixed work/rest cycles where the time-at-work does is ≤8 hours and there is >1 rest period per day, on average, for ≥2 consecutive days. These schedules are commonly used in safety-critical industries such as transport and maritime industries. Literature was sourced using PubMed, Embase, PsycInfo, Scopus, and Google Scholar databases. We identified 20 independent studies (plus a further 2 overlapping studies), including 5 laboratory and 17 field-based studies focused on maritime watch keepers, ship bridge officers, and long-haul train drivers. The measurement of outcome measures was varied, incorporating subjective and objective measures of sleep: sleep diaries (N=5), actigraphy (N=4), and polysomnography, (N=3); sleepiness: Karolinska Sleepiness Scale (N=5), visual analog scale (VAS) alertness (N=2) and author-derived measures (N=2); and performance: Psychomotor Vigilance Test (PVT) (N=5), Reaction Time or Vigilance tasks (N=4), Vector and Letter Cancellation Test (N=1), and subjective performance (N=2). Of the three primary rosters examined (6 hours-on/6 hours-off, 8 hours-on/8 hours-off and 4 hours-on/8 hours-off), the 4 hours-on/8 hours-off roster was associated with better sleep and lower levels of sleepiness. Individuals working 4 hours-on/8 hours-off rosters averaged 1 hour more sleep per night than those working 6 hours-on/6 hours-off and 1.3 hours more sleep than those working 8 hours-on/8 hours-off (Pwork, (ii) more frequent rest breaks, (iii) shifts that start and end at the same clock time every 24 hours, and (iv) work shifts commencing in the daytime (as opposed to night). The findings for performance remain incomplete due to the small number of studies containing a performance measure and the heterogeneity of performance measures within those that did. The literature supports the utility of LWSW in

  8. Crush performance of redwood for developing design procedures for impact limiters

    International Nuclear Information System (INIS)

    Cramer, S.M.; Hermanson, J.C.; McMurtry, W.M.

    1995-01-01

    Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most simplistic information exists on its crush properties. Tbe stress-strain interrelationship for any wood species subject to three-dimensional stresses is largely unknown for any all stress condition and wood behavior at both high strains and high strain-rates is known only in general terms. Both stress-strain and crush failure theories have been developed based only on uniaxial load tests. The anisotropy of wood adds an additional complexity to measuring wood response and developing suitable theories to describe it. A long history of wood utilization in the building industry has led to design procedures and property information related to simple uniaxial loadings that do not inflict damage to the wood. This lack of knowledge may be surprising for a material that has a long history of engineered use, but the result is difficulty in utilizing wood in more sophisticated designs such as impact limiters. This study provides a step toward filling the information gap on wood material response for high performance applications such as impact limiters

  9. Limits to sustainable muscle performance: interaction between glycolysis and oxidative phosphorylation.

    Science.gov (United States)

    Conley, K E; Kemper, W F; Crowther, G J

    2001-09-01

    This paper proposes a mechanism responsible for setting the sustainable level of muscle performance. Our contentions are that the sustainable work rate is determined (i) at the muscle level, (ii) by the ability to maintain ATP supply and (iii) by the products of glycolysis that may inhibit the signal for oxidative phosphorylation. We argue below that no single factor 'limits' sustainable performance, but rather that the flux through and the interaction between glycolysis and oxidative phosphorylation set the level of sustainable ATP supply. This argument is based on magnetic resonance spectroscopy measurements of the sources and sinks for energy in vivo in human muscle and rattlesnake tailshaker muscle during sustained contractions. These measurements show that glycolysis provides between 20% (human muscle) and 40% (tailshaker muscle) of the ATP supply during sustained contractions in these muscles. We cite evidence showing that this high glycolytic flux does not reflect an O(2) limitation or mitochondria operating at their capacity. Instead, this flux reflects a pathway independent of oxidative phosphorylation for ATP supply during aerobic exercise. The consequence of this high glycolytic flux is accumulation of H(+), which we argue inhibits the rise in the signal activating oxidative phosphorylation, thereby restricting oxidative ATP supply to below the oxidative capacity. Thus, both glycolysis and oxidative phosphorylation play important roles in setting the highest steady-state ATP synthesis flux and thereby determine the sustainable level of work by exercising muscle.

  10. Rotary engine performance limits predicted by a zero-dimensional model

    Science.gov (United States)

    Bartrand, Timothy A.; Willis, Edward A.

    1992-01-01

    A parametric study was performed to determine the performance limits of a rotary combustion engine. This study shows how well increasing the combustion rate, insulating, and turbocharging increase brake power and decrease fuel consumption. Several generalizations can be made from the findings. First, it was shown that the fastest combustion rate is not necessarily the best combustion rate. Second, several engine insulation schemes were employed for a turbocharged engine. Performance improved only for a highly insulated engine. Finally, the variability of turbocompounding and the influence of exhaust port shape were calculated. Rotary engines performance was predicted by an improved zero-dimensional computer model based on a model developed at the Massachusetts Institute of Technology in the 1980's. Independent variables in the study include turbocharging, manifold pressures, wall thermal properties, leakage area, and exhaust port geometry. Additions to the computer programs since its results were last published include turbocharging, manifold modeling, and improved friction power loss calculation. The baseline engine for this study is a single rotor 650 cc direct-injection stratified-charge engine with aluminum housings and a stainless steel rotor. Engine maps are provided for the baseline and turbocharged versions of the engine.

  11. Nanocomposites of graphene oxide and upconversion rare-earth nanocrystals with superior optical limiting performance

    KAUST Repository

    Wei, Wei

    2012-04-20

    Upconversion rare-earth nanomaterials (URENs) possess highly efficient near-infrared (NIR), e.g., 980 nm, laser absorption and unique energy upconversion capabilities. On the other hand, graphene and its derivatives, such as graphene oxide (GO), show excellent performance in optical limiting (OL); however, the wavelengths of currently used lasers for OL studies mainly focus on either 532 or 1064 nm. To design new-generation OL materials working at other optical regions, such as the NIR, a novel nanocomposites, GO-URENs, which combines the advantages of both its components, is synthesized by a one-step chemical reaction. Transmission electron microscopy, X-ray diffraction, infrared spectroscopy, and fluorescence studies prove that the α-phase URENs uniformly attach on the GO surface via covalent chemical bonding, which assures highly efficient energy transfer between URENs and GO, and also accounts for the significantly improved OL performance compared to either GO or URENs. The superior OL effect is also observed in the proof-of-concept thin-film product, suggesting immediate applications in making high-performance laser-protecting products and optoelectronic devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Centralized motion control of a linear tooth belt drive: Analysis of the performance and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, M.

    2010-07-01

    A centralized robust position control for an electrical driven tooth belt drive is designed in this doctoral thesis. Both a cascaded control structure and a PID based position controller are discussed. The performance and the limitations of the system are analyzed and design principles for the mechanical structure and the control design are given. These design principles are also suitable for most of the motion control applications, where mechanical resonance frequencies and control loop delays are present. One of the major challenges in the design of a controller for machinery applications is that the values of the parameters in the system model (parameter uncertainty) or the system model it self (non-parametric uncertainty) are seldom known accurately in advance. In this thesis a systematic analysis of the parameter uncertainty of the linear tooth beltdrive model is presented and the effect of the variation of a single parameter on the performance of the total system is shown. The total variation of the model parameters is taken into account in the control design phase using a Quantitative Feedback Theory (QFT). The thesis also introduces a new method to analyze reference feedforward controllers applying the QFT. The performance of the designed controllers is verified by experimental measurements. The measurements confirm the control design principles that are given in this thesis. (orig.)

  13. Performance of the MACRO limited streamer tubes for estimates of muon energy

    CERN Document Server

    Giorgini, M

    2002-01-01

    The MACRO limited streamer tubes can be operated in drift mode by using the TDCs included in the QTP system. In this way a considerable improvement in the space resolution is obtained, allowing the analysis of muon tracks in terms of multiple scattering effects and the energy estimates of muons crossing the detector. We present the results of two dedicated tests, performed with the CERN PS-T9 and SPS-X7 beams, to provide a full check of the electronics and to exploit the feasibility of the analysis. Using a neural network, we are able to estimate the muon energies up to E/sub mu / approximately = 40 GeV. The test beam data provide then an absolute energy calibration, which allows to apply the method to the MACRO data. (5 refs).

  14. Performance Limitations Analysis of Imperfect Attenuators for Adaptive Self-Interference Cancellation System

    Directory of Open Access Journals (Sweden)

    J. Liu

    2016-09-01

    Full Text Available Radio frequency (RF adaptive self-interference cancellation system (RFAICS is extensively used to suppress the self-interference of radios operating in the same platform, such as military command vehicles, airplanes and navy vessels. RFAICS is generally consisted of couplers, attenuators, delay units, amplifiers, and filters and so on. However, RFAICS usually suffers severely from the imperfect attenuators. This paper firstly explores the RFAICS operation process in theory, and then thoroughly investigates and analyzes the negative effects of non-ideal attenuators on performance of RFAICS. The closed-form expressions fully describing the influences of attenuation bias and response-time respectively on the interference cancellation ratio (ICR and system convergence time (SCT are developed with this aim. Simulations are provided for the validity of the limitation analysis and obtained expressions. Results of simulations are in agreement with theoretical analysis, which is significant for component configuration in taking RFAICS into practice.

  15. Auger generation as an intrinsic limit to tunneling field-effect transistor performance

    International Nuclear Information System (INIS)

    Teherani, James T.; Agarwal, Sapan; Chern, Winston; Antoniadis, Dimitri A.; Solomon, Paul M.; Yablonovitch, Eli

    2016-01-01

    Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

  16. Influence of CFC quality on the performance of TS limiter elements under cyclic heat loading

    International Nuclear Information System (INIS)

    Missirlian, M.; Greuner, H.; Hoeschen, T.; Linsmeier, Ch.; Richou, M.; Lipa, M.; Boeswirth, B.; Boscary, J.

    2011-01-01

    For the fabrication of 600 actively cooled finger elements for the Tore Supra pump limiter in operation since 2001 it was necessary to rely on two different batches of the CFC N11 grade (Carbon Fibre reinforced Composite) namely so-called SEP N11-92 (fabricated in 1992) and N11-98 (fabricated in 1998). It came out during the incoming inspection of the fingers that the bonding quality was degraded for the 98-batch so that an important number of tiles had to be repaired. Due to the coming upgrade of the Tore Supra heating system, two high heat flux test campaigns were performed on the neutral beam GLADIS facility (IPP Garching, Germany) including micro-structural analyses in order to evaluate, compare and understand the fatigue behaviour of 92- and 98-batch finger elements.

  17. Auger generation as an intrinsic limit to tunneling field-effect transistor performance

    Energy Technology Data Exchange (ETDEWEB)

    Teherani, James T., E-mail: j.teherani@columbia.edu [Department of Electrical Engineering, Columbia University, New York, New York 10027 (United States); Agarwal, Sapan [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Chern, Winston; Antoniadis, Dimitri A. [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Solomon, Paul M. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Yablonovitch, Eli [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

    2016-08-28

    Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance.

  18. Upgrading the Performance of Cholesteric Liquid Crystal Lasers: Improvement Margins and Limitations

    Directory of Open Access Journals (Sweden)

    Josu Ortega

    2017-12-01

    Full Text Available The topic of cholesteric-liquid-crystal lasers is a rapidly expanding research area in the field of soft-matter photonics. The increasing interest in this field is due to the high versatility that these lasers may possibly present and the prospects of giving rise to new miniaturized devices. However, further improvements in their operation capabilities are still required for potential applications. In this paper, we critically analyze the main strategies proposed up to now to optimize their performance. We show theoretically and experimentally that possible innovations in the device structure cannot produce lasers with threshold energies below a certain limit. This limit is determined by the light scattering and absorption losses inside the liquid crystal. Even assuming the case of samples free of defects and perfectly non-absorbing, an intrinsic light scattering, typical of mesogens, still remains. Numerical estimates of the thresholds indicate that these lasers could hardly be driven by compact light sources such as current electroluminescent or light-emitting diodes. Since the improvement possibilities regarding cell architecture seem to be exhausted, the advance must come from the use of new dye molecules. These molecules should show enhanced emission cross-sections and be efficiently integrable within the mesogenic solvent. In addition, the fluorescent systems must present very small quantum yields to triplet states if continuous-wave lasing is sought. In this respect, quantum dots are an alternative to explore for further investigations.

  19. Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species.

    Energy Technology Data Exchange (ETDEWEB)

    T.B. Harrington; C.M. Dagley; M.B. Edwards.

    2003-10-01

    Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition and needlefall from overstory pines on understory plant performance. Three 13- to 15-yr-old plantations near Aiken, SC, were thinned to 0, 25, 50, or 100% of nonthinned basal area (19.5 m2 ha-1). Combinations of trenching (to eliminate root competition) and needlefall were applied to areas within each plot, and containerized seedlings of 14 perennial herbaceous species and longleaf pine were planted within each. Overstory crown closure ranged from 0 to 81%, and soil water and available nitrogen varied consistently with pine stocking, trenching, or their combination. Cover of planted species decreased an average of 16.5 and 14.1% as a result of above- and below-ground competition, respectively. Depending on species, needlefall effects were positive, negative, or negligible. Results indicate that understory restoration will be most successful when herbaceous species are established within canopy openings (0.1-0.2 ha) managed to minimize negative effects from above- and belowground competition and needlefall.

  20. Performance limits of ICA-based heart rate identification techniques in imaging photoplethysmography

    International Nuclear Information System (INIS)

    Mannapperuma, Kavan; Holton, Benjamin D; Lesniewski, Peter J; Thomas, John C

    2015-01-01

    Imaging photoplethysmography is a relatively new technique for extracting biometric information from video images of faces. This is useful in non-invasive monitoring of patients including neonates or the aged, with respect to sudden infant death syndrome, sleep apnoea, pulmonary disease, physical or mental stress and other cardio-vascular conditions. In this paper, we investigate the limits of detection of the heart rate (HR) while reducing the video quality. We compare the performance of three independent component analysis (ICA) methods (JADE, FastICA, RADICAL), autocorrelation with signal conditioning techniques and identify the most robust approach. We discuss sources of increasing error and other limiting conditions in three situations of reduced signal-to-noise ratio: one where the area of the analyzed face is decreased from 100 to 5%, another where the face area is progressively re-sampled down to a single RGB pixel and one where the HR signal is severely reduced with respect to the boundary noise. In most cases, the cardiac pulse rate can be reliably and accurately detected from videos containing only 5% facial area or from a face occupying just 4 pixels or containing only 5% of the facial HR modulation. (paper)

  1. Design Dependent Cutoff Frequency of Nanotransistors Near the Ultimate Performance Limit

    Science.gov (United States)

    Kordrostami, Zoheir; Sheikhi, M. Hossein; Zarifkar, Abbas

    2012-12-01

    We have studied the effect of different structural designs of double gate MOSFETs (DG-MOSFETs) and carbon nanotube field effect transistors (CNTFETs) on the cutoff frequency (fT). The effects of metallic contacts with Schottky barriers, gate work function, dual material gate (DMG), halo doped channel and lightly doped drain and source (LDDS) architectures on the fT have been investigated for DG-MOSFETs and CNTFETs and the design dependent fT for both types of transistors has been studied for the first time. The simulations are based on the Schrödinger-Poisson solvers developed for each nanotransistor separately. The ballistic limit has been studied as the ultimate performance limit of the DG-MOSFETs and CNTFETs. The results of this paper, for the first time, show how some designations used for modification of short channel effects or current-voltage characteristics affect the fT. The results revealed that the cutoff frequencies of both types of the transistors exhibit the same behavior with changing design parameters. We have shown that the Schottky barriers, parasitic capacitances and halo doping reduce the fT and have proposed the DMG and LDDS artchitectures as ways to increase the fT for DG-MOSFETs and CNTFETs for the first time.

  2. Limiting Performance Analysis of Underwater Shock Isolation of a System with Biodynamic Response Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Z. Zong

    2000-01-01

    Full Text Available Biodynamic response of shipboard crew to underwater shock is of a major concern to navies. An underwater shock can produce very high accelerations, resulting in severe human injuries aboard a battleship. Protection of human bodies from underwater shock is implemented by installing onboard isolators. In this paper, the optimal underwater shock isolation to protect human bodies is studied. A simple shock-structure-isolator-human interaction model is first constructed. The model incorporates the effect of fluid-structure interaction, biodynamic response of human body, isolator influence. Based on this model, the optimum shock isolation is then formulated. The performance index and restriction are defined. Thirdly, GA (genetic algorithm is employed to solve the formulated optimization problem. GA is a powerful evolutionary optimization scheme suitable for large-scale and multi-variable optimization problems that are otherwise hard to be solved by conventional methods. A brief introduction to GA is given in the paper. Finally, the method is applied to an example problem and the limiting performance characteristic is obtained.

  3. Explore the performance limit of a solar PV – thermochemical power generation system

    International Nuclear Information System (INIS)

    Li, Wenjia; Hao, Yong

    2017-01-01

    Highlights: •Theoretical net solar-to-electric efficiency of 51.5% is attainable. •Design of efficient PVT systems is governed by at least 5 key considerations. •Concentration ratio has the most pronounced influence on PVT system efficiency. •Efficient PV, low emissivity and high concentration deliver the best performance. -- Abstract: Performance limit of a solar hybrid power generation system integrating efficient photovoltaic (PV) cells and methanol thermal (T) decomposition is explored from a thermodynamic perspective within the capability of state-of-the-art technologies. This type of PVT system features potentially high “net solar-to-electric efficiency” in general, primarily resulting from a key difference in the design of the thermal part compared with conventional PVT systems, i.e. replacing heat engines by a thermochemical power generation module for thermal energy utilization. Key design parameters of the system, including PV cell type, emissivity, solar concentration ratio and solar concentrator type, are individually studied. A system combining all such optimized aspects is projected to achieve net solar-to-electric efficiencies up to 51.5%, after taking all major (e.g. optical, radiative) losses into consideration. This study reveals important insights and enriches understanding on design principles of efficient PVT systems aimed at comprehensive and effective utilization of solar energy.

  4. Properties of magnetic photonic crystals in the visible spectral region and their performance limitations

    Science.gov (United States)

    Kotov, V. A.; Shavrov, V. G.; Vasiliev, M.; Alameh, K.; Nur-E-Alam, M.; Balabanov, D. E.

    2018-02-01

    We report on the results of computer modelling and performance analysis of the optical and magneto-optical (MO) characteristics of one-dimensional magnetic photonic crystals (MPC) of several classic design types (having either a single structure defect, or a number of these), designed for applications in the visible spectral region. The calculations are performed accounting for the real levels of optical absorption achievable in existing MO materials which currently demonstrate the best MO quality (bismuth-substituted ferrite garnets). We consider Bi2Dy1Fe4Ga1O12 as the base material for use within quarter-wave thick MO layers of MPC; silica is used for the non-magnetic transparent quarter-wave layers. The achieved results can be used to clarify the nature of the differences that exist between the expected practical potential of MPCs in integrated photonics, and the actual attained experimental results. Our results show that in MPCs optimized for light intensity modulation applications, in the red spectral region (near 650 nm), the achievable levels of optical transmission are limited to about 30%. This coincides spectrally with the peaks of Faraday rotation reaching their maxima at about 25°, with further transmission increases possible in the near-infrared region. Larger Faraday rotation angles are only achievable currently in structures or single film layers with reduced transmission.

  5. Performance limitations of imaging microscopes for soft x-ray applications

    International Nuclear Information System (INIS)

    Lewotsky, K.L.; Kotha, A.; Harvey, J.E.

    1993-01-01

    Recent advances in the fabrication of nanometer-scale multilayer structures have yielded high-reflectance mirrors operating at near-normal incidence for soft X-ray wavelengths. These developments have stimulated renewed interest in high-resolution soft X-ray microscopy. The design of a Schwarzschild imaging microscope for soft X-ray applications has been reported by Hoover and Shealy. Based upon a geometrical ray-trace analysis of the residual design errors, diffraction-limited performance at a wavelength of 100 angstrom was predicted over an object size (diameter) of 0.4 mm. In this paper the authors expand upon the previous analysis of the Schwarzschild X-ray microscope design by determining the total image degradation due to diffraction, geometrical aberrations, alignment errors, and realistic assumptions concerning optical fabrication errors. NASA's Optical Surface Analysis Code (OSAC) is used to model the image degradation effects of residual surface irregularities over the entire range of relevant spatial frequencies. This includes small angle scattering effects due to mid spatial frequency surface errors falling between the traditional figure and finish specifications. Performance predictions are presented parametrically to provide some insight into the optical fabrication and alignment tolerances necessary to meet a particular image quality requirement

  6. Performance assessments of nuclear waste repositories--A dialogue on their value and limitations

    Science.gov (United States)

    Ewing, Rodney C.; Tierney, Martin S.; Konikow, Leonard F.; Rechard, Rob P.

    1999-01-01

    Performance Assessment (PA) is the use of mathematical models to simulate the long-term behavior of engineered and geologic barriers in a nuclear waste repository; methods of uncertainty analysis are used to assess effects of parametric and conceptual uncertainties associated with the model system upon the uncertainty in outcomes of the simulation. PA is required by the U.S. Environmental Protection Agency as part of its certification process for geologic repositories for nuclear waste. This paper is a dialogue to explore the value and limitations of PA. Two “skeptics” acknowledge the utility of PA in organizing the scientific investigations that are necessary for confident siting and licensing of a repository; however, they maintain that the PA process, at least as it is currently implemented, is an essentially unscientific process with shortcomings that may provide results of limited use in evaluating actual effects on public health and safety. Conceptual uncertainties in a PA analysis can be so great that results can be confidently applied only over short time ranges, the antithesis of the purpose behind long-term, geologic disposal. Two “proponents” of PA agree that performance assessment is unscientific, but only in the sense that PA is an engineering analysis that uses existing scientific knowledge to support public policy decisions, rather than an investigation intended to increase fundamental knowledge of nature; PA has different goals and constraints than a typical scientific study. The “proponents” describe an ideal, sixstep process for conducting generalized PA, here called probabilistic systems analysis (PSA); they note that virtually all scientific content of a PA is introduced during the model-building steps of a PSA, they contend that a PA based on simple but scientifically acceptable mathematical models can provide useful and objective input to regulatory decision makers. The value of the results of any PA must lie between these two

  7. To what extent might N2 limit dive performance in king penguins?

    Science.gov (United States)

    Fahlman, A; Schmidt, A; Jones, D R; Bostrom, B L; Handrich, Y

    2007-10-01

    A mathematical model was used to explore if elevated levels of N2, and risk of decompression sickness (DCS), could limit dive performance (duration and depth) in king penguins (Aptenodytes patagonicus). The model allowed prediction of blood and tissue (central circulation, muscle, brain and fat) N2 tensions (P(N2)) based on different cardiac outputs and blood flow distributions. Estimated mixed venous P(N2) agreed with values observed during forced dives in a compression chamber used to validate the assumptions of the model. During bouts of foraging dives, estimated mixed venous and tissue P(N2) increased as the bout progressed. Estimated mean maximum mixed venous P(N2) upon return to the surface after a dive was 4.56+/-0.18 atmospheres absolute (ATA; range: 4.37-4.78 ATA). This is equivalent to N2 levels causing a 50% DCS incidence in terrestrial animals of similar mass. Bout termination events were not associated with extreme mixed venous N2 levels. Fat P(N2) was positively correlated with bout duration and the highest estimated fat P(N2) occurred at the end of a dive bout. The model suggested that short and shallow dives occurring between dive bouts help to reduce supersaturation and thereby DCS risk. Furthermore, adipose tissue could also help reduce DCS risk during the first few dives in a bout by functioning as a sink to buffer extreme levels of N2.

  8. Short Communication: Comparison of Maxim and Sedia Limiting Antigen Assay Performance for Measuring HIV Incidence.

    Science.gov (United States)

    Schlusser, Katherine E; Konikoff, Jacob; Kirkpatrick, Allison R; Morrison, Charles; Chipato, Tsungai; Chen, Pai-Lien; Munjoma, Marshall; Eshleman, Susan H; Laeyendecker, Oliver

    2017-06-01

    Accurate methods for cross-sectional incidence estimation are needed for HIV prevention research. The Limiting Antigen Avidity (LAg-Avidity) assay has been marketed by two vendors, Maxim Biomedical and Sedia BioSciences Corporation. Performance differences between the two versions of the assay are unknown. We tested a total 1,410 treatment-naive samples with both versions of the assay. The samples came from 176 seroconverters from the Zimbabwe Hormonal Contraception and HIV Study. The correlation between the two versions of the assay was 0.93 for the optical density (OD) and 0.86 for the normalized OD. As the difference was more pronounced for the normalized OD, the difference in assays can be attributed to the calibrators. The mean duration of recent infection (MDRI), the average time individuals infected 1,000 copies/ml. The MDRI was 137 days for Sedia and 157 days for Maxim, with a difference of 20 days (95% CI 11-30). The MDRIs decreased to 102 and 120 days with the inclusion of a viral load cutoff of >1,000 copies/ml. These results imply that use of the Sedia LAg-Avidity will result in estimates of incidence ∼13% lower than those using the Maxim LAg-Avidity.

  9. Assessing control of postural stability in community-living older adults using performance-based limits of stability

    DEFF Research Database (Denmark)

    Jbabdi, Myriam; Boissy, Patrice; Hamel, Mathieu

    2008-01-01

    BACKGROUND: Balance disability measurements routinely used to identify fall risks in frail populations have limited value in the early detection of postural stability deficits in community-living older adults. The objectives of the study were to 1) measure performance-based limits of stability (LOS......-session performance variability during multiple trials using the performance-based LOS paradigm. METHODS: Twenty-four healthy community-living older adults (10 men, 14 women) aged between 62 to 85 (mean age +/- sd, 71.5 +/- 6 yrs) participated in the study. Subjects' performance-based LOS were established by asking...

  10. Air quality indicators from the Environmental Performance Index: potential use and limitations in South Africa

    Directory of Open Access Journals (Sweden)

    Rebecca M. Garland

    2017-06-01

    Full Text Available In responding to deteriorating air quality, many countries, including South Africa, have implemented national programmes that aim to manage and regulate ambient air quality, and the emissions of air pollutants. One aspect within these management strategies is effective communication to stakeholders, including the general public, with regard to the state and trend of ambient air quality in South Africa. Currently, information on ambient air quality is communicated through ambient mass concentration values, as well as number of exceedances of South African National Ambient Standards. However, these do not directly communicate the potential impact on human health and the ecosystem. To this end, the use of air quality indicators is seen as a potential way to achieve communication to stakeholders in a simplified, yet scientifically defensible manner. Air quality indicators and their source data from the Environmental Performance Index (EPI were interrogated to understand their potential use in South Africa. An assessment of four air quality indicators, together with their source data, showed improvements in air quality over the time period studied, though the input data do have uncertainties. The source data for the PM indicators, which came from a global dataset, underestimated the annual PM2.5 concentrations in the Highveld Priority Area and Vaal Triangle Airshed Priority Area over the time period studied (2009-2014 by ~3.7 times. This highlights a key limitation of national-scale indicators and input data, that while the data used by the EPI are a well-thought out estimate of a country’s air quality profile, they remain a generalised estimate. The assumptions and uncertainty inherent in such an ambitious global-wide attempt make the estimates inaccurate for countries without proper emissions tracking and accounting and few monitoring stations, such as South Africa. Thus, the inputs and resultant indicators should be used with caution until such

  11. Impact of optical hard limiter on the performance of an optical overlapped-code division multiple access system

    Science.gov (United States)

    Inaty, Elie; Raad, Robert; Tablieh, Nicole

    2011-08-01

    Throughout this paper, a closed form expression of the multiple access interference (MAI) limited bit error rate (BER) is provided for the multiwavelength optical code-division multiple-access system when the system is working above the nominal transmission rate limit imposed by the passive encoding-decoding operation. This system is known in literature as the optical overlapped code division multiple access (OV-CDMA) system. A unified analytical framework is presented emphasizing the impact of optical hard limiter (OHL) on the BER performance of such a system. Results show that the performance of the OV-CDMA system may be highly improved when using OHL preprocessing at the receiver side.

  12. Performance Analysis of a Power Limited Spectrum Sharing System with TAS/MRC

    KAUST Repository

    Khan, Fahd Ahmed; Tourki, Kamel; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2014-01-01

    multiple antennas on the secondary network terminals and performing antenna selection. In this paper, the performance of a multiple-input multiple-output (MIMO) secondary link with transmit antenna selection (TAS) at the transmitter and maximum ratio

  13. Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas

    International Nuclear Information System (INIS)

    J.E. Menard; M.G. Bell; R.E. Bell; E.D. Fredrickson D.A. Gates: S.M. Kaye; B.P. LeBlanc; R. Maingi; D. Mueller; S.A. Sabbagh; D. Stutman; C.E. Bush; D.W. Johnson; R. Kaita; H.W. Kugel; R.J. Maqueda; F. Paoletti; S.F Paul; M. Ono; Y.-K.M. Peng; C.H. Skinner; E.J. Synakowski; the NSTX Research Team

    2003-01-01

    Global magnetohydrodynamic stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized beta and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during normal operation and increased the maximum achievable beta. As a result of these improvements, peak beta values have reached (not simultaneously) β t = 35%, β N = 6.4, N > = 4.5, β N /l i = 10, and β P = 1.4. High β P operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 second with sustained periods of β N ∼ 6 above the ideal no-wall limit and near the with-wall limit. Details of the β limit scalings and β-limiting instabilities in various operating regimes are described

  14. Performance and stability limits at near-unity aspect ratio in the Pegasus Toroidal Experiment

    International Nuclear Information System (INIS)

    Fonck, R.J.

    2002-01-01

    The Pegasus Toroidal Experiment is a mid-sized extremely-low aspect ratio (A) spherical torus (ST). It has the dual roles of exploring limits of ST behavior as A approaches 1 and studying the physics of ST plasmas in the tokamak-spheromak overlap regime. Major parameters are R 0.25 - 0.45 m, A 1.1 - 1.4, I p ≤ 0.15MA, and B t p =aB t is similar to that observed for NBI-heated START discharges. Achievable plasma current apparently is subject to a 'soft' limit of I p =I t f ≤ 1. Access to higher-current plasmas appears to be restricted by the appearance of large internal MHD activity, including m/n=2/1 and 3/2 modes. Recent experiments have begun to access ideal stability limits, with disruptions observed as q 95 approaches 5, in agreement with numerical predictions. (author)

  15. Non-Foster Circuits for High Performance Antennas: Advantages and Practical Limitations

    Science.gov (United States)

    Jacob, Minu Mariam

    The demand for miniaturized, broadband communication systems has created a need for electrically small, broadband antennas. However, all passive electrically small antennas have a fundamental gain-bandwidth limitation related to their electrical size, as first described by Wheeler and Chu. This limitation can be overcome using active non-Foster circuits (negative inductors and/or negative capacitors), which can deliver a broadband input match with active matching techniques, or can help reduce phase dispersion using negative delay effects. This thesis will illustrate the advantages of non-Foster circuits in obtaining broadband small antennas, in addition to examining their practical limitations due to noise in receive applications, and nonlinearity in transmit applications.

  16. Beta-limiting MHD instabilities in improved performance NSTX spherical torus plasmas

    International Nuclear Information System (INIS)

    Menard, J.E.; Bell, M.G.; Bell, R.E.

    2003-01-01

    Global magnetohydrodynamic stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized beta and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during nor- mal operation and increased the maximum achievable beta. As a result of these improvements, peak beta values have reached (not simultaneously) β t = 35%, β N 6.5, N > = 4.5, β / l i =10, and β= 1.4. High β P operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 second with sustained periods of β N ∼ 6. Details of the β limit scalings and β-limiting instabilities in various operating regimes are described. (author)

  17. Effects of Supply Chain Risk Management on Organization Performance: Case of Andy Forwarders Services Limited

    OpenAIRE

    Caroline Wanjiru Munyuko

    2015-01-01

    The purpose of the research was to determine the effects of Supply chain risk management on organization performance. Previous studies have focused on risk management within the general context of an organization but little attention has been focused on how supply chain risk affect organization performance in terms of its bottom line profits and overall organization objectives. Particular attention was paid to the effects of supply chain risk management variables to the performance of the org...

  18. The impact of power limitations and adjacent residence interference on the performance of WLANs for home networking applications

    OpenAIRE

    Armour, SMD; Doufexi, A; Lee, BS; Nix, AR; Bull, DR

    2001-01-01

    This paper considers the application of 5 GHz wireless LAN technology to home networking applications. An assessment of physical layer performance is presented for both the IEEE 802.11a and HIPERLAN/2 standards in the form of achievable data rate as a function of received signal to noise ratio. The transmit power limitations imposed by the relevant regulatory bodies are presented and the implications of transmit power amplifier limitations considered. Based on this information, a state of the...

  19. Are altitudinal limits of equatorial stream insects reflected in their respiratory performance?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Brodersen, Klaus Peter

    2008-01-01

    .6 between genera at 17 °C, and from 1.3 to 2.5 at 5 °C. Q10 values for this temperature interval ranged 1.5-2.9 (mean 2.3). The two "high-altitude" genera had higher respiration rates at low temperature and oxygen saturation, and their respiration rate saturated at lower temperatures, than three of the four......-term physiological tolerance of low temperature and oxygen concentration. 5. Multiple regressions (based on respiration experiments and previously obtained relationships between water temperature, oxygen saturation and altitude) were used to predict how respiration rates should vary with altitude. At the upper limit...... saturation. Further quantitative and long-term studies on survival and recruitment in populations and communities are needed to determine the importance of temperature and oxygen for altitudinal limits of aquatic insects....

  20. Influence of gas mixture and primary ionization on the performance of limit streamer mode tubes

    International Nuclear Information System (INIS)

    An Jigang; Anderson, K.J.; Merritt, F.S.; Oreglia, M.; Pilcher, J.E.; Possoz, A.; Schappert, W.; Chicago Univ., IL

    1988-01-01

    We report a study of the dependence of limited streamer mode operation on gas composition. Results are given for the plateau onset voltage, plateau length, charge versus voltage, charge spectra and pulse width for various fractions of (Ar, CO 2 , pentane) and (Ar, isobutane). In addition, a series of argon-free strong quenching gas mixtures has been studied which have very attractive characteristics. Chamber lifetime tests for these are also reported. As part of a study of the nature of the limited streamer mode mechanism, the response to X-rays and minimum ionizing particles are compared and differences noted. The character of the primary ionization is found to have a clear effect on the chamber response even in the streamer region. (orig.)

  1. Performance and stability limits at near-unity aspect ratio in the pegasus toroidal experiment

    International Nuclear Information System (INIS)

    Fonck, R.; Diem, S.; Garstka, G.; Kissick, M.; Lewicki, B.; Ostrander, C.; Probert, P.; Reinke, M.; Sontag, A.; Tritz, K.; Unterberg, E.

    2003-01-01

    The Pegasus Toroidal Experiment is a mid-sized extremely-low aspect ratio (A) spherical torus (ST). It has the dual roles of exploring limits of ST behavior as A approaches 1 and studying the physics of ST plasmas in the tokamak-spheromak overlap regime. Major parameters are R 0.25 - 0.45 m, A 1.1 - 1.4, I p T 20% have been obtained, and the operational space of beta vs I p /aB T is similar to that observed for NBI-heated START discharges. Achievable plasma current is subject to an apparent limit of I p /I tf ∼ 1. Access to higher-current plasmas appears to be restricted by the appearance of large internal MHD activity, including m/n=2/1 and 3/2 modes. Recent experiments have begun to access ideal stability limits, with disruptions observed as q 95 approaches 5, in agreement with numerical predictions for external kink mode onset. (author)

  2. Performance and limitations of steatosis biomarkers in patients with nonalcoholic fatty liver disease.

    Science.gov (United States)

    Fedchuk, L; Nascimbeni, F; Pais, R; Charlotte, F; Housset, C; Ratziu, V

    2014-11-01

    Several steatosis biomarkers are available with limited independent validation. To determine diagnostic value and limitations of several steatosis biomarkers using liver biopsy as reference standard in a large cohort of patients with suspected NAFLD. Three hundred and twenty-four consecutive liver biopsies were included. Histological steatosis was categorised as none (66%). Five steatosis biomarkers were measured: fatty liver index (FLI), NAFLD liver fat score (NAFLD-LFS), hepatic steatosis index (HSI), visceral adiposity index (VAI) and triglyceride × glucose (TyG) index. Steatosis grades prevalence was: none 5%, mild 39%, moderate 30% and severe 27%. Except for VAI, the steatosis biomarkers showed a linear trend across the steatosis grades. However, their correlation with the histological amount of steatosis was only weak-moderate. All steatosis biomarkers had an adequate diagnostic accuracy for the presence of steatosis: AUROCs for FLI, LFS, HSI, VAI and TyG were 0.83, 0.80, 0.81, 0.92 and 0.90. However, their ability to quantify steatosis was poor: none of them distinguished between moderate and severe steatosis and the AUROCs for predicting steatosis >33% were 0.65, 0.72, 0.65, 0.59 and 0.59 for FLI, LFS, HSI, VAI and TyG. Both fibrosis and inflammation significantly confounded the association between steatosis biomarkers and steatosis. The steatosis biomarkers were all correlated with HOMA-IR, independent from histological steatosis. All five steatosis biomarkers can diagnose steatosis and are correlated with insulin resistance. They are confounded by fibrosis and inflammation, and do not accurately quantify steatosis; this may limit their clinical utility. More research is needed to identify truly independent and quantitative markers of steatosis. © 2014 John Wiley & Sons Ltd.

  3. High performance H-mode plasmas at densities above the Greenwald limit

    International Nuclear Information System (INIS)

    Mahdavi, M.A.; Osborne, T.H.; Leonard, A.W.

    2001-01-01

    Densities up to 40 percent above the Greenwald limit are reproducibly achieved in high confinement (H ITER89p =2) ELMing H-mode discharges. Simultaneous gas fueling and divertor pumping were used to obtain these results. Confinement of these discharges, similar to moderate density H-mode, is characterized by a stiff temperature profile, and therefore sensitive to the density profile. A particle transport model is presented that explains the roles of divertor pumping and geometry for access to high densities. Energy loss per ELM at high density is a factor of five lower than predictions of an earlier scaling, based on data from lower density discharges. (author)

  4. H/D exchange mass spectrometry and statistical coupling analysis reveal a role for allostery in a ferredoxin-dependent bifurcating transhydrogenase catalytic cycle.

    Science.gov (United States)

    Berry, Luke; Poudel, Saroj; Tokmina-Lukaszewska, Monika; Colman, Daniel R; Nguyen, Diep M N; Schut, Gerrit J; Adams, Michael W W; Peters, John W; Boyd, Eric S; Bothner, Brian

    2018-01-01

    Recent investigations into ferredoxin-dependent transhydrogenases, a class of enzymes responsible for electron transport, have highlighted the biological importance of flavin-based electron bifurcation (FBEB). FBEB generates biomolecules with very low reduction potential by coupling the oxidation of an electron donor with intermediate potential to the reduction of high and low potential molecules. Bifurcating systems can generate biomolecules with very low reduction potentials, such as reduced ferredoxin (Fd), from species such as NADPH. Metabolic systems that use bifurcation are more efficient and confer a competitive advantage for the organisms that harbor them. Structural models are now available for two NADH-dependent ferredoxin-NADP + oxidoreductase (Nfn) complexes. These models, together with spectroscopic studies, have provided considerable insight into the catalytic process of FBEB. However, much about the mechanism and regulation of these multi-subunit proteins remains unclear. Using hydrogen/deuterium exchange mass spectrometry (HDX-MS) and statistical coupling analysis (SCA), we identified specific pathways of communication within the model FBEB system, Nfn from Pyrococus furiosus, under conditions at each step of the catalytic cycle. HDX-MS revealed evidence for allosteric coupling across protein subunits upon nucleotide and ferredoxin binding. SCA uncovered a network of co-evolving residues that can provide connectivity across the complex. Together, the HDX-MS and SCA data show that protein allostery occurs across the ensemble of iron‑sulfur cofactors and ligand binding sites using specific pathways that connect domains allowing them to function as dynamically coordinated units. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Limitations in intense exercise performance of athletes - effect of speed endurance training on ion handling and fatigue development

    DEFF Research Database (Denmark)

    Hostrup, Morten; Bangsbo, Jens

    2017-01-01

    Mechanisms underlying fatigue development and limitations for performance during intense exercise have been intensively studied during the past couple of decades. Fatigue development may involve several interacting factors and depends on type of exercise undertaken and training level of the indiv...

  6. Materials Genome in Action: Identifying the Performance Limits of Physical Hydrogen Storage

    Science.gov (United States)

    2017-01-01

    The Materials Genome is in action: the molecular codes for millions of materials have been sequenced, predictive models have been developed, and now the challenge of hydrogen storage is targeted. Renewably generated hydrogen is an attractive transportation fuel with zero carbon emissions, but its storage remains a significant challenge. Nanoporous adsorbents have shown promising physical adsorption of hydrogen approaching targeted capacities, but the scope of studies has remained limited. Here the Nanoporous Materials Genome, containing over 850 000 materials, is analyzed with a variety of computational tools to explore the limits of hydrogen storage. Optimal features that maximize net capacity at room temperature include pore sizes of around 6 Å and void fractions of 0.1, while at cryogenic temperatures pore sizes of 10 Å and void fractions of 0.5 are optimal. Our top candidates are found to be commercially attractive as “cryo-adsorbents”, with promising storage capacities at 77 K and 100 bar with 30% enhancement to 40 g/L, a promising alternative to liquefaction at 20 K and compression at 700 bar. PMID:28413259

  7. Suggestions on performance of finite element limit analysis for eliminating the necessity of stress classifications in design and defect assessment

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2001-07-01

    In structural design of a nuclear power component, stress classification from elastic stress analysis resultants is often used. Alternatively, to improve accuracy, finite element limit analysis may be performed. This paper examines some issues relating to the use of limit analysis; specifically, the treatment of multiple applied loads and the definition of the limit load from analysis using hardening plasticity laws. These are addressed both by detailed analysis for a simple geometry and by using the reference stress approach to estimate the inelastic displacement. The proposals are also applicable to a defect assessment of a cracked component, and treatment of distributed loads. It is shown that multiple or distributed loads should be treated as if they were applied proportionally irrespective of the actual nature of loads, and that the limit load from analysis with general plasticity laws may be estimated using a newly suggested reduced elastic slope method. (author)

  8. Suggestions on performance of finite element limit analysis for eliminating the necessity of stress classifications in design and defect assessment

    International Nuclear Information System (INIS)

    Fujioka, T.

    2001-01-01

    In structural design of a nuclear power component, stress classification from elastic stress analysis resultants is often used. Alternatively, to improve accuracy, finite element limit analysis may be performed. This paper examines some issues relating to the use of limit analysis; specifically, the treatment of multiple applied loads and the definition of the limit load from analysis using hardening plasticity laws. These are addressed both by detailed analysis for a simple geometry and by using the reference stress approach to estimate the inelastic displacement. The proposals are also applicable to a defect assessment of a cracked component, and treatment of distributed loads. It is shown that multiple or distributed loads should be treated as if they were applied proportionally irrespective of the actual nature of loads, and that the limit load from analysis with general plasticity laws may be estimated using a newly suggested reduced elastic slope method. (author)

  9. English Value-Added Measures: Examining the Limitations of School Performance Measurement

    Science.gov (United States)

    Perry, Thomas

    2016-01-01

    Value-added "Progress" measures are to be introduced for all English schools in 2016 as "headline" measures of school performance. This move comes despite research highlighting high levels of instability in value-added measures and concerns about the omission of contextual variables in the planned measure. This article studies…

  10. Update in the understanding of altitude-induced limitations to performance in team-sport athletes.

    Science.gov (United States)

    Billaut, François; Aughey, Robert J

    2013-12-01

    The internationalism of field-based team sports (TS) such as football and rugby requires teams to compete in tournaments held at low to moderate altitude (∼1200-2500 m). In TS, acceleration, speed and aerobic endurance are physical characteristics associated with ball possession and, ultimately, scoring. While these qualities are affected by the development of neuromuscular fatigue at sea level, arterial hypoxaemia induced by exposure to altitude may further hinder the capacity to perform consecutive accelerations (CAC) or sprint endurance and thereby change the outcome of a match. The higher the altitude, the more severe the hypoxaemia, and thus, the larger the expected decline in aerobic endurance, CAC and match running performance. Therefore, it is critical for athletes and coaches to understand how arterial hypoxaemia affects aerobic endurance and CAC and the magnitude of decline they may face at altitude for optimal preparation and increased chances of success. This mini review summarises the effects of acute altitude/hypoxia exposure on aerobic endurance, CAC and activity profiles of TS athletes performing in the laboratory and during matches at natural altitude, and analyses the latest findings about the consequences of arterial hypoxaemia on the relationship between peripheral perturbations, neural adjustments and performance during repeated sprints or CAC. Finally, we briefly discuss how altitude training can potentially help athletes prepare for competition at altitude.

  11. The Impact of IFRS 16 on the Companies’ Key Performance Indicators: Limits, Advantages and Drawbacks

    OpenAIRE

    Alin Eliodor Tanase; Traian Ovidiu Calota; Florin Razvan Oncioiu

    2018-01-01

    t This article focuses on the impact of the new standard IFRS 16 Leases on the companies’ key performance indicators. The magnitude of this impact could be said to change depending on the usage density of the lease in the companies and also depending on the sector they are in. The results show that future transactions may be influenced by IFRS 16 such as sale and leaseback, acquisitions and mergers, and lease vs. buying.

  12. Thermal Performance and Operation Limit of Heat Pipe Containing Neutron Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Mo; Jeong, Yeong Shin; Kim, In Guk; Bang, In Choel [UNIST, Ulsan (Korea, Republic of)

    2015-05-15

    Recently, passive safety systems are under development to ensure the core cooling in accidents involving impossible depressurization such as station blackout (SBO). Hydraulic control rod drive mechanisms, passive auxiliary feedwater system (PAFS), Passive autocatalystic recombiner (PAR), and so on are types of passive safety systems to enhance the safety of nuclear power plants. Heat pipe is used in various engineering fields due to its advantages in terms of easy fabrication, high heat transfer rate, and passive heat transfer. Also, the various concepts associated with safety system and heat transfer using the heat pipe were developed in nuclear engineering field.. Thus, our group suggested the hybrid control rod which combines the functions of existing control rod and heat pipe. If there is significant temperature difference between active core and condenser, the hybrid control rod can shutdown the nuclear fission reaction and remove the decay heat from the core to ultimate heat sink. The unique characteristic of the hybrid control rod is the presence of neutron absorber inside the heat pipe. Many previous researchers studied the effect of parameters on the thermal performance of heat pipe. However, the effect of neutron absorber on the thermal performance of heat pipe has not been investigated. Thus, the annular heat pipe which contains B{sub 4}C pellet in the normal heat pipe was prepared and the thermal performance of the annular heat pipe was studied in this study. Hybrid control rod concept was developed as a passive safety system of nuclear power plant to ensure the safety of the reactor at accident condition. The hybrid control rod must contain the neutron absorber for the function as a control rod. So, the effect of neutron absorber on the thermal performance of heat pipe was experimentally investigated in this study. Temperature distributions at evaporator section of annular heat pipe were lower than normal heat pipe due to the larger volume occupied by

  13. Performance Analysis of a Power Limited Spectrum Sharing System with TAS/MRC

    KAUST Repository

    Khan, Fahd Ahmed

    2014-02-01

    Capacity of the cognitive radio network degrades due to the interference constraint from the primary network. The secondary network capacity can be enhanced in a cost effective way by means of spatial diversity, that can be achieved by adding multiple antennas on the secondary network terminals and performing antenna selection. In this paper, the performance of a multiple-input multiple-output (MIMO) secondary link with transmit antenna selection (TAS) at the transmitter and maximum ratio combining (MRC) at the receiver is analyzed. A peak transmit power constraint at the secondary transmitter is considered in addition to the interference power constraint and two scenarios are considered; 1) the MIMO cognitive system with TAS/MRC (MCS-TM) does not experience interference from the primary network (denote by MCS-TM-NI), and 2) MCS-TM does experience interference from the primary network (denote by MCS-TM-WI). The performance of both MCS-TM-NI and MCS-TM-WI is analyzed and, for a Rayleigh faded channel, closed-form expression for the outage probability is derived. In addition, closed-form expressions of the moment generating function, the symbol error rate and the ergodic capacity are obtained for the MCS-TM-NI. Asymptotic performance analysis of the MCS-TM-NI reveals that TAS/MRC in a MIMO cognitive system achieves a generalized diversity gain equal to the product of the number of transmit and receive antennas. Numerical results are also presented to corroborate the derived analytical results. © 1991-2012 IEEE.

  14. The Impact of IFRS 16 on the Companies’ Key Performance Indicators: Limits, Advantages and Drawbacks

    Directory of Open Access Journals (Sweden)

    Alin Eliodor Tanase

    2018-03-01

    Full Text Available t This article focuses on the impact of the new standard IFRS 16 Leases on the companies’ key performance indicators. The magnitude of this impact could be said to change depending on the usage density of the lease in the companies and also depending on the sector they are in. The results show that future transactions may be influenced by IFRS 16 such as sale and leaseback, acquisitions and mergers, and lease vs. buying.

  15. Myocellular limitations of human performance and their modification through genome-dependent responses at altitude.

    Science.gov (United States)

    Flueck, Martin

    2010-03-01

    Human muscle operates along a continuum of power output, which is set through bioenergetic and anatomical principles. In turn, environmental and intrinsic factors during contractile work exert pronounced control over muscle performance by instructing muscle remodelling. This phenotypic control is specifically indicated with intense exercise at altitude, when extra strain is put on energy supply and the temperature-dependent mechanical efficiency of contraction. While it is classically thought that chronic exposure to hypoxia is maladaptive, repeated short episodes of reduced oxygenation alone or in combination with intense endurance work is now understood to preserve exercise performance when atmospheric oxygen levels are low. Endurance training at moderate altitude exploits the temperature-dependent malleability of energy supply that may maximize metabolic flux at altitude. The contribution of genomic mechanisms is important to the plasticity of metabolic pathways in exercised muscle. This is highlighted by the association of distinct gene polymorphisms in master governors of mitochondrial and vascular growth with exercise phenotypes. Feedforward control of human locomoter muscle by exercise involves the transient upregulation of transcript expression for metabolic processes. The response of the mitochondrial transcriptome to intense exercise is graded with respect to mitochondrial content and deoxygenation during muscle work and reflects exercise-induced mitochondrial biogenesis. This supports the notion that genome-mediated muscle malleability is under feedback control by design constraints of the pathway of oxygen. Thus, activity-dependent and genetic mechanisms contribute to the interindividual difference in the metabolic bottlenecks in athletes performing in exceptional environmental conditions.

  16. Using Mason number to predict MR damper performance from limited test data

    Science.gov (United States)

    Becnel, Andrew C.; Wereley, Norman M.

    2017-05-01

    The Mason number can be used to produce a single master curve which relates MR fluid stress versus strain rate behavior across a wide range of shear rates, temperatures, and applied magnetic fields. As applications of MR fluid energy absorbers expand to a variety of industries and operating environments, Mason number analysis offers a path to designing devices with desired performance from a minimal set of preliminary test data. Temperature strongly affects the off-state viscosity of the fluid, as the passive viscous force drops considerably at higher temperatures. Yield stress is not similarly affected, and stays relatively constant with changing temperature. In this study, a small model-scale MR fluid rotary energy absorber is used to measure the temperature correction factor of a commercially-available MR fluid from LORD Corporation. This temperature correction factor is identified from shear stress vs. shear rate data collected at four different temperatures. Measurements of the MR fluid yield stress are also obtained and related to a standard empirical formula. From these two MR fluid properties - temperature-dependent viscosity and yield stress - the temperature-corrected Mason number is shown to predict the force vs. velocity performance of a full-scale rotary MR fluid energy absorber. This analysis technique expands the design space of MR devices to high shear rates and allows for comprehensive predictions of overall performance across a wide range of operating conditions from knowledge only of the yield stress vs. applied magnetic field and a temperature-dependent viscosity correction factor.

  17. Performance and limitations of positron emission tomography (PET) scanners for imaging very low activity sources.

    Science.gov (United States)

    Freedenberg, Melissa I; Badawi, Ramsey D; Tarantal, Alice F; Cherry, Simon R

    2014-02-01

    Emerging applications for positron emission tomography (PET) may require the ability to image very low activity source distributions in the body. The performance of clinical PET scanners in the regime where activity in the field of view is source in the NEMA scatter phantom), the BGO-based scanner significantly outperformed the LSO-based scanner. This was largely due to the effect of background counts emanating from naturally occurring but radioactive (176)Lu within the LSO detector material, which dominates the observed counting rate at the lowest activities. Increasing the lower energy threshold from 350 keV to 425 keV in an attempt to reduce this background did not significantly improve the measured NECR performance. The measured singles rate due to (176)Lu emissions within the scanner energy window was also found to be dependent on temperature, and to be affected by the operation of the CT component, making approaches to correct or compensate for the background more challenging. We conclude that for PET studies in a very low activity range, BGO-based scanners are likely to have better performance because of the lack of significant background. Copyright © 2013 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  18. Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes.

    Science.gov (United States)

    Lebeau, Julie; Wesselingh, Renate A; Van Dyck, Hans

    2016-05-11

    Flight is an essential biological ability of many insects, but is energetically costly. Environments under rapid human-induced change are characterized by habitat fragmentation and may impose constraints on the energy income budget of organisms. This may, in turn, affect locomotor performance and willingness to fly. We tested flight performance and metabolic rates in meadow brown butterflies (Maniola jurtina) of two contrasted agricultural landscapes: intensively managed, nectar-poor (IL) versus extensively managed, nectar-rich landscapes (EL). Young female adults were submitted to four nectar treatments (i.e. nectar quality and quantity) in outdoor flight cages. IL individuals had better flight capacities in a flight mill and had lower resting metabolic rates (RMR) than EL individuals, except under the severest treatment. Under this treatment, RMR increased in IL individuals, but decreased in EL individuals; flight performance was maintained by IL individuals, but dropped by a factor 2.5 in EL individuals. IL individuals had more canalized (i.e. less plastic) responses relative to the nectar treatments than EL individuals. Our results show significant intraspecific variation in the locomotor and metabolic response of a butterfly to different energy income regimes relative to the landscape of origin. Ecophysiological studies help to improve our mechanistic understanding of the eco-evolutionary impact of anthropogenic environments on rare and widespread species. © 2016 The Author(s).

  19. Extending the Performance of Hybrid NoCs beyond the Limitations of Network Heterogeneity

    Directory of Open Access Journals (Sweden)

    Michael Opoku Agyeman

    2017-04-01

    Full Text Available To meet the performance and scalability demands of the fast-paced technological growth towards exascale and big data processing with the performance bottleneck of conventional metal-based interconnects (wireline, alternative interconnect fabrics, such as inhomogeneous three-dimensional integrated network-on-chip (3D NoC and hybrid wired-wireless network-on-chip (WiNoC, have emanated as a cost-effective solution for emerging system-on-chip (SoC design. However, these interconnects trade off optimized performance for cost by restricting the number of area and power hungry 3D routers and wireless nodes. Moreover, the non-uniform distributed traffic in a chip multiprocessor (CMP demands an on-chip communication infrastructure that can avoid congestion under high traffic conditions while possessing minimal pipeline delay at low-load conditions. To this end, in this paper, we propose a low-latency adaptive router with a low-complexity single-cycle bypassing mechanism to alleviate the performance degradation due to the slow 2D routers in such emerging hybrid NoCs. The proposed router transmits a flit using dimension-ordered routing (DoR in the bypass datapath at low-loads. When the output port required for intra-dimension bypassing is not available, the packet is routed adaptively to avoid congestion. The router also has a simplified virtual channel allocation (VA scheme that yields a non-speculative low-latency pipeline. By combining the low-complexity bypassing technique with adaptive routing, the proposed router is able to balance the traffic in hybrid NoCs to achieve low-latency communication under various traffic loads. Simulation shows that the proposed router can reduce applications’ execution time by an average of 16.9% compared to low-latency routers, such as SWIFT. By reducing the latency between 2D routers (or wired nodes and 3D routers (or wireless nodes, the proposed router can improve the performance efficiency in terms of average

  20. Pushing the Performance Limit of Sub-100 nm Molybdenum Disulfide Transistors.

    Science.gov (United States)

    Liu, Yuan; Guo, Jian; Wu, Yecun; Zhu, Enbo; Weiss, Nathan O; He, Qiyuan; Wu, Hao; Cheng, Hung-Chieh; Xu, Yang; Shakir, Imran; Huang, Yu; Duan, Xiangfeng

    2016-10-12

    Two-dimensional semiconductors (2DSCs) such as molybdenum disulfide (MoS 2 ) have attracted intense interest as an alternative electronic material in the postsilicon era. However, the ON-current density achieved in 2DSC transistors to date is considerably lower than that of silicon devices, and it remains an open question whether 2DSC transistors can offer competitive performance. A high current device requires simultaneous minimization of the contact resistance and channel length, which is a nontrivial challenge for atomically thin 2DSCs, since the typical low contact resistance approaches for 2DSCs either degrade the electronic properties of the channel or are incompatible with the fabrication process for short channel devices. Here, we report a new approach toward high-performance MoS 2 transistors by using a physically assembled nanowire as a lift-off mask to create ultrashort channel devices with pristine MoS 2 channel and self-aligned low resistance metal/graphene hybrid contact. With the optimized contact in short channel devices, we demonstrate sub-100 nm MoS 2 transistor delivering a record high ON-current of 0.83 mA/μm at 300 K and 1.48 mA/μm at 20 K, which compares well with that of silicon devices. Our study, for the first time, demonstrates that the 2DSC transistors can offer comparable performance to the 2017 target for silicon transistors in International Technology Roadmap for Semiconductors (ITRS), marking an important milestone in 2DSC electronics.

  1. The importance of human performance and procedures in limiting severe accident risks

    International Nuclear Information System (INIS)

    Higgins, J.C.

    1990-01-01

    Due to the defense in depth concept and redundancy in safety systems utilized, complex industrial plants, such as nuclear power plants (NPPs) can be operated safely. This capability has been demonstrated by many years of safe operation by numerous NPPs in the US and abroad. However, the occurrence of severe accidents has also demonstrated that constant vigilance in a number of areas is necessary to ensure continued safe operation. The areas noted as particularly important are Design, Organization and Management, Maintenance, and Operations (Human Performance). 18 refs

  2. On the performance limiting behavior of defect clusters in commercial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L.; Chen, W.; Jones, K. [National Renewable Energy Lab., Golden, CO (United States); Gee, J. [Sandia National Labs., Albuquerque, NM (United States)

    1998-09-01

    The authors report the observation of defect clusters in high-quality, commercial silicon solar cell substrates. The nature of the defect clusters, their mechanism of formation, and precipitation of metallic impurities at the defect clusters are discussed. This defect configuration influences the device performance in a unique way--by primarily degrading the voltage-related parameters. Network modeling is used to show that, in an N/P junction device, these regions act as shunts that dissipate power generated within the cell.

  3. Second advanced ICFA beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings

    International Nuclear Information System (INIS)

    Hagel, J.; Keil, E.

    1988-01-01

    These proceedings contain the papers presented at the 'Second advanced beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings', which was organized in Lugano, Switzerland, from 11 to 16 April 1988, by the Beam Dynamics Panel of the International Committee for Future Accelerators (ICFA). The papers cover experiments on existing accelerators, analytical methods for determining amplitude limitations, criteria for the properties of the circulating beam and for the quality of accelerator components, and compensation schemes for field defects. (orig.)

  4. Exercise hyperthermia as a factor limiting physical performance - Temperature effect on muscle metabolism

    Science.gov (United States)

    Kozlowski, S.; Brzezinska, Z.; Kruk, B.; Kaciuba-Uscilko, H.; Greenleaf, J. E.

    1985-01-01

    The effect of trunk cooling on the muscle contents of ATP, ADP, AMP, creatine phosphate (CrP), and creatine, as well as of glycogen, some glycolytic intermediates, pyruvate, and lactate were assessed in 11 fasted dogs exercised at 20 C on treadmill to exhaustion. Without cooling, dogs were able to run 57 min, and their rectal (Tre) and muscle (Tm) temperatures increased to 41.8 and 43.0 C, respectively. Cooling with ice packs prolonged the ability to run by 45 percent, and resulted in lower Tre (by 1.1 C) and Tm (by 1.2 C). Depletion of muscle content of total high-energy phosphates (ATP + CrP) and glycogen, and increases in contents of AMP, pyruvate, and lactate were lower in cooled dogs than in non-cooled dogs. The muscle content of lactiate correlated positively with TM. These results indicate that hypothermia accelerates glycolysis, and shifts the equilibrium between high- and low-energy phosphates in favor of the latter. The adverse effect of hypothermia on muscle metabolism may be relevant to the limitation of endurance.

  5. Performance limits of ion extraction systems with non-circular apertures

    Energy Technology Data Exchange (ETDEWEB)

    Shagayda, A., E-mail: shagayda@gmail.com; Madeev, S. [Keldysh Research Centre, Onezhskaya, 8, 125438 Moscow (Russian Federation)

    2016-04-15

    A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

  6. Performance limits of ion extraction systems with non-circular apertures.

    Science.gov (United States)

    Shagayda, A; Madeev, S

    2016-04-01

    A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

  7. Update of a thermodynamic database for radionuclides to assist solubility limits calculation for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Duro, L.; Grive, M.; Cera, E.; Domenech, C.; Bruno, J. (Enviros Spain S.L., Barcelona (ES))

    2006-12-15

    This report presents and documents the thermodynamic database used in the assessment of the radionuclide solubility limits within the SR-Can Exercise. It is a supporting report to the solubility assessment. Thermodynamic data are reviewed for 20 radioelements from Groups A and B, lanthanides and actinides. The development of this database is partially based on the one prepared by PSI and NAGRA. Several changes, updates and checks for internal consistency and completeness to the reference NAGRA-PSI 01/01 database have been conducted when needed. These modifications are mainly related to the information from the various experimental programmes and scientific literature available until the end of 2003. Some of the discussions also refer to a previous database selection conducted by Enviros Spain on behalf of ANDRA, where the reader can find additional information. When possible, in order to optimize the robustness of the database, the description of the solubility of the different radionuclides calculated by using the reported thermodynamic database is tested in front of experimental data available in the open scientific literature. When necessary, different procedures to estimate gaps in the database have been followed, especially accounting for temperature corrections. All the methodologies followed are discussed in the main text

  8. Update of a thermodynamic database for radionuclides to assist solubility limits calculation for performance assessment

    International Nuclear Information System (INIS)

    Duro, L.; Grive, M.; Cera, E.; Domenech, C.; Bruno, J.

    2006-12-01

    This report presents and documents the thermodynamic database used in the assessment of the radionuclide solubility limits within the SR-Can Exercise. It is a supporting report to the solubility assessment. Thermodynamic data are reviewed for 20 radioelements from Groups A and B, lanthanides and actinides. The development of this database is partially based on the one prepared by PSI and NAGRA. Several changes, updates and checks for internal consistency and completeness to the reference NAGRA-PSI 01/01 database have been conducted when needed. These modifications are mainly related to the information from the various experimental programmes and scientific literature available until the end of 2003. Some of the discussions also refer to a previous database selection conducted by Enviros Spain on behalf of ANDRA, where the reader can find additional information. When possible, in order to optimize the robustness of the database, the description of the solubility of the different radionuclides calculated by using the reported thermodynamic database is tested in front of experimental data available in the open scientific literature. When necessary, different procedures to estimate gaps in the database have been followed, especially accounting for temperature corrections. All the methodologies followed are discussed in the main text

  9. Performance limits of ion extraction systems with non-circular apertures

    Science.gov (United States)

    Shagayda, A.; Madeev, S.

    2016-04-01

    A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

  10. Performance limits of ion extraction systems with non-circular apertures

    International Nuclear Information System (INIS)

    Shagayda, A.; Madeev, S.

    2016-01-01

    A three-dimensional computer simulation is used to determine the perveance limitations of ion extraction systems with non-circular apertures. The objective of the study is to analyze the possibilities to improve mechanical strength of the ion optics made of carbon-carbon composite materials. Non-circular grid apertures are better suited to the physical structure of carbon-carbon composite materials, than conventionally used circular holes in a hexagonal pattern, because they allow a fewer number of cut fibers. However, the slit-type accelerating systems, usually regarded as the main alternative to the conventional ion optics, have an intolerably narrow range of operating perveance values at which there is no direct ion impingement on the acceleration grid. This paper presents results of comparative analysis of a number of different ion optical systems with non-circular apertures and conventional ion optical systems with circular apertures. It has been revealed that a relatively wide perveance range without direct ion impingement may be obtained with apertures shaped as a square with rounded corners. Numerical simulations show that this geometry may have equivalent perveance range as the traditional geometry with circular apertures while being more mechanically robust. In addition, such important characteristics, as the effective transparency for both the ions and the neutral atoms, the height of the potential barrier reflecting the downstream plasma electrons and the angular divergence of the beamlet also can be very close to these parameters for the optics with circular apertures.

  11. Alkali Metal-O2 Batteries. Performance and Lifetime Limiting Effects

    DEFF Research Database (Denmark)

    Knudsen, Kristian Bastholm

    The rechargeable Na-O2 and Li-O2 batteries are attractive battery technologies as they potentially are very cheap and as they theoretically possess about 3 and 10 times higher energy density than the current Li-ion technologies. This PhD thesis is dedicated to studying the effects that limit cell...... product, Li2O2, was investigated. This was done by using of a conventional three electrode cell in which the heterogeneous electron transfer rate of three different redox couples were studied on Li2O2 coated glassy carbon electrodes to provide a measure of the conductivity of the Li2O2 layers. Charge....... The capacitance of the cathode was shown to be sensitive to the thickness of the deposited Li2O2 layer. These investigations also explored the influence of the composition of the electrolyte and conditions, which favors a solution mediated Li2O2 deposition mechanism. On charge, an electrochemical “safe” operating...

  12. Funnel plot control limits to identify poorly performing healthcare providers when there is uncertainty in the value of the benchmark.

    Science.gov (United States)

    Manktelow, Bradley N; Seaton, Sarah E; Evans, T Alun

    2016-12-01

    There is an increasing use of statistical methods, such as funnel plots, to identify poorly performing healthcare providers. Funnel plots comprise the construction of control limits around a benchmark and providers with outcomes falling outside the limits are investigated as potential outliers. The benchmark is usually estimated from observed data but uncertainty in this estimate is usually ignored when constructing control limits. In this paper, the use of funnel plots in the presence of uncertainty in the value of the benchmark is reviewed for outcomes from a Binomial distribution. Two methods to derive the control limits are shown: (i) prediction intervals; (ii) tolerance intervals Tolerance intervals formally include the uncertainty in the value of the benchmark while prediction intervals do not. The probability properties of 95% control limits derived using each method were investigated through hypothesised scenarios. Neither prediction intervals nor tolerance intervals produce funnel plot control limits that satisfy the nominal probability characteristics when there is uncertainty in the value of the benchmark. This is not necessarily to say that funnel plots have no role to play in healthcare, but that without the development of intervals satisfying the nominal probability characteristics they must be interpreted with care. © The Author(s) 2014.

  13. 3D MODELING OF INDUSTRIAL HERITAGE BUILDING USING COTSs SYSTEM: TEST, LIMITS AND PERFORMANCES

    Directory of Open Access Journals (Sweden)

    M. Piras

    2017-08-01

    Full Text Available The role of UAV systems in applied geomatics is continuously increasing in several applications as inspection, surveying and geospatial data. This evolution is mainly due to two factors: new technologies and new algorithms for data processing. About technologies, from some years ago there is a very wide use of commercial UAV even COTSs (Commercial On-The-Shelf systems. Moreover, these UAVs allow to easily acquire oblique images, giving the possibility to overcome the limitations of the nadir approach related to the field of view and occlusions. In order to test potential and issue of COTSs systems, the Italian Society of Photogrammetry and Topography (SIFET has organised the SBM2017, which is a benchmark where all people can participate in a shared experience. This benchmark, called “Photogrammetry with oblique images from UAV: potentialities and challenges”, permits to collect considerations from the users, highlight the potential of these systems, define the critical aspects and the technological challenges and compare distinct approaches and software. The case study is the “Fornace Penna” in Scicli (Ragusa, Italy, an inaccessible monument of industrial architecture from the early 1900s. The datasets (images and video have been acquired from three different UAVs system: Parrot Bebop 2, DJI Phantom 4 and Flytop Flynovex. The aim of this benchmark is to generate the 3D model of the “Fornace Penna”, making an analysis considering different software, imaging geometry and processing strategies. This paper describes the surveying strategies, the methodologies and five different photogrammetric obtained results (sensor calibration, external orientation, dense point cloud and two orthophotos, using separately – the single images and the frames extracted from the video – acquired with the DJI system.

  14. D Modeling of Industrial Heritage Building Using COTSs System: Test, Limits and Performances

    Science.gov (United States)

    Piras, M.; Di Pietra, V.; Visintini, D.

    2017-08-01

    The role of UAV systems in applied geomatics is continuously increasing in several applications as inspection, surveying and geospatial data. This evolution is mainly due to two factors: new technologies and new algorithms for data processing. About technologies, from some years ago there is a very wide use of commercial UAV even COTSs (Commercial On-The-Shelf) systems. Moreover, these UAVs allow to easily acquire oblique images, giving the possibility to overcome the limitations of the nadir approach related to the field of view and occlusions. In order to test potential and issue of COTSs systems, the Italian Society of Photogrammetry and Topography (SIFET) has organised the SBM2017, which is a benchmark where all people can participate in a shared experience. This benchmark, called "Photogrammetry with oblique images from UAV: potentialities and challenges", permits to collect considerations from the users, highlight the potential of these systems, define the critical aspects and the technological challenges and compare distinct approaches and software. The case study is the "Fornace Penna" in Scicli (Ragusa, Italy), an inaccessible monument of industrial architecture from the early 1900s. The datasets (images and video) have been acquired from three different UAVs system: Parrot Bebop 2, DJI Phantom 4 and Flytop Flynovex. The aim of this benchmark is to generate the 3D model of the "Fornace Penna", making an analysis considering different software, imaging geometry and processing strategies. This paper describes the surveying strategies, the methodologies and five different photogrammetric obtained results (sensor calibration, external orientation, dense point cloud and two orthophotos), using separately - the single images and the frames extracted from the video - acquired with the DJI system.

  15. Driving imaging and overlay performance to the limits with advanced lithography optimization

    Science.gov (United States)

    Mulkens, Jan; Finders, Jo; van der Laan, Hans; Hinnen, Paul; Kubis, Michael; Beems, Marcel

    2012-03-01

    Immersion lithography is being extended to 22-nm and even below. Next to generic scanner system improvements, application specific solutions are needed to follow the requirements for CD control and overlay. Starting from the performance budgets, this paper discusses how to improve (in volume manufacturing environment) CDU towards 1-nm and overlay towards 3-nm. The improvements are based on deploying the actuator capabilities of the immersion scanner. The latest generation immersion scanners have extended the correction capabilities for overlay and imaging, offering freeform adjustments of lens, illuminator and wafer grid. In order to determine the needed adjustments the recipe generation per user application is based on a combination wafer metrology data and computational lithography methods. For overlay, focus and CD metrology we use an angle resolved optical scatterometer.

  16. Performance limits of energy harvesting communications under imperfect channel state information

    KAUST Repository

    Zenaidi, Mohamed Ridha

    2016-07-26

    In energy harvesting communications, the transmitters have to adapt transmission to availability of energy harvested during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the causality and energy storage constraints. We determine the optimal offline policy in the case where the channel is assumed to be perfectly known at the receiver. Also, we obtain the power policy when the transmitter has no CSI. Furthermore, we analyze the asymptotic average throughput in a system where the average recharge rate goes asymptotically to zero. © 2016 IEEE.

  17. Performance of intact and partially degraded concrete barriers in limiting fluid flow

    International Nuclear Information System (INIS)

    Walton, J.C.; Seitz, R.R.

    1991-07-01

    Concrete barriers will play a critical role in the long-term isolation of low-level radioactive wastes. Over time the barriers will degrade, and in many cases, the fundamental processes controlling performance of the barriers will be different for intact and degraded conditions. This document examines factors controlling fluid flow through intact and degraded concrete disposal facilities. Simplified models are presented fro predicting build up of fluid above a vault; fluid flow through and around intact vaults, through flaws in coatings/liners applied to a vault, and through cracks in a concrete vault; and the influence of different backfill materials around the outside of the vault. Example calculations are presented to illustrate the parameters and processes that influence fluid flow. 46 refs., 49 figs., 2 tabs

  18. Multiple Antennas Systems and Full Duplex Relay Systems with Hardware Impairments: New Performance Limits

    KAUST Repository

    Javed, Sidrah

    2016-12-01

    Next generation of wireless communication mostly relies on multiple-input multipleoutput (MIMO) configuration and full-duplex relaying to improve data-rates, spectrale efficiency, spatial-multiplexing, quality-of-service and energy-efficiency etc. However, multiple radio frequency (RF) transceivers in MIMO system and multi-hops in relay networks, accumulate transceiver impairments, rendering an unacceptable system performance. Majority of the technical contributions either assume ideal hardware or inappropriately model hardware impairments which often induce misleading results especially for high data-rate communication systems. We propose statistical mathematical modeling of various hardware impairment (HWI) to characterize their deteriorating effects on the information signal. In addition, we model the aggregate HWI as improper Gaussian signaling (IGS), to fully characterize their asymmetric properties and the self-interfering signal attribute under I/Q imbalance. The proposed model encourages to adopt asymmetric transmission scheme, as opposed to traditional symmetric signaling. First, we present statistical baseband equivalent mathematical models for general MIMO system and two special scenarios of receive and transmit diversity systems under HWI. Then, we express their achievable rate under PGS and IGS transmit schemes. Moreover, we tune the IGS statistical characteristics to maximize the achievable rate. We also present optimal beam-forming/pre-coding and receive combiner vector for multiple-input single-output (MISO) and single-input multiple output (SIMO) systems, which lead to SDNR maximization. Moreover, we propose an adaptive scheme to switch between maximal IGS (MIGS) and PGS transmission based on the described conditions to reduce computational overhead. Subsequently, two case studies are presented. 1) Outage analysis has been carried out for SIMO, under transceiver distortion noise, for two diversity combining schemes 2) The benefits of employing IGS

  19. Validity limits of fuel rod performance calculations from radiochemical data at operating LWRs

    International Nuclear Information System (INIS)

    Zaenker, H.; Nebel, D.

    1986-01-01

    There are various calculational models for the assessment of the fuel rod performance on the basis of the activities of gaseous and volatile fission products in the reactor coolant. The most important condition for the applicability of the calculational models is that a steady state release of the fission products into the reactor coolant takes place. It is well known that the models are not applicable during or shortly after reactor transients. The fact that 'unsteady states' caused by the fuel defection processes themselves can also occur in rare cases at steady reactor operation has not been taken into account so far. A test of validity is suggested with the aid of which the applicability of the calculational models can be checked in any concrete case, and the misleading of the reactor operators by gross misinterpretation of the radiochemical data can be avoided. The criteria of applicability are the fission product total activity, the slope tan α in the relationship lg (R/sub i//B/sub i/) proportional to lg lambda/sub i/ for the gaseous and volatile fission products, and the activity of the nonvolatile isotope 239 Np. (author)

  20. Performance Limits of Online Energy Harvesting Communications with Noisy Channel State Information at the Transmitter

    KAUST Repository

    Zenaidi, Mohamed Ridha

    2017-03-01

    In energy harvesting communications, the transceivers have to adjust the data transmission to the energy scavenged during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this paper, we consider the problem of power allocation taking into account the energy arrivals over time and the quality of channel state information (CSI) measured at the transmitter, in order to maximize the throughput. Differently from previous work, we focus on energy harvesting communications where the CSI at the transmitter is not perfect and may include estimation errors. In the present paper, we introduce a Markov process that models the energy arrival process. Indeed, we solve the throughput maximization problem with respect to energy harvesting constraints. We show that the optimal online power policy can be found using dynamic programming. Furthermore, we study the asymptotic behavior of the communication system at low and high average recharge rate (ARR) regime. Selected numerical results are provided to support our analysis.

  1. Performance Limits of Energy Harvesting Communications under Imperfect Channel State Information

    KAUST Repository

    Zenaidi, Mohamed Ridah

    2015-01-07

    In energy harvesting communications, the transmitters have to adapt transmission to availability of energy harvested during the course of communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. In this work, we consider the problem of power allocation taking into account the energy arrivals over time and the degree of channel state information (CSI) available at the transmitter, in order to maximize the throughput. In this work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the causality and energy storage constraints. We determine the optimal offline policy in the case where the channel is assumed to be perfectly known at the receiver. Different cases of CSI availability are studied for the transmitter. We obtain the power policy when the transmitter has either perfect CSI or no CSI. We also investigate of utmost interest the case of fading channels with imperfect CSI. Furthermore, we analyze the asymptotic average throughput in a system where the average recharge rate goes asymptotically to zero and when it is very high.

  2. Performance Evaluation of Distributed Mobility Management Protocols: Limitations and Solutions for Future Mobile Networks

    Directory of Open Access Journals (Sweden)

    J. Carmona-Murillo

    2017-01-01

    Full Text Available Mobile Internet data traffic has experienced an exponential growth over the last few years due to the rise of demanding multimedia content and the increasing number of mobile devices. Seamless mobility support at the IP level is envisioned as a key architectural requirement in order to deal with the ever-increasing demand for data and to efficiently utilize a plethora of different wireless access networks. Current efforts from both industry and academia aim to evolve the mobility management protocols towards a more distributed operation to tackle shortcomings of fully centralized approaches. However, distributed solutions face several challenges that can result in lower performance which might affect real-time and multimedia applications. In this paper, we conduct an analytical and simulated evaluation of the main centralized and proposed Distributed Mobility Management (DMM solutions. Our results show that, in some scenarios, when users move at high speed and/or when the mobile node is running long-lasting applications, the DMM approaches incur high signaling cost and long handover latency.

  3. Thriving at the limit: Differential reproductive performance in range-edge populations of a Mediterranean sclerophyll (Olea europaea)

    Science.gov (United States)

    Granado-Yela, Carlos; Balaguer, Luis; García-Verdugo, Carlos; Carrillo, Katty; Méndez, Marcos

    2013-10-01

    Peripheral populations are often lumped together on the assumption of thriving in marginal habitats where reproductive performance is compromised. We have tested this hypothesis in peripheral populations of wild olive tree (Olea europaea L.) presumably limited by different factors at the westernmost limit of the species range. Additionally, we hypothesized that differences in reproductive outcome among populations are better explained by site-specific environmental conditions (PAR, soil water, soil nutrients, air humidity and air temperature) than by differences in phenotypic traits (tree size and leaf traits). To test these hypotheses, we assessed the number of flowering trees, the flowering intensity, fruit set and seed viability in eight populations for three consecutive years. Our findings provided sufficient evidence to reject the first hypothesis. Peripheral populations that occur under oceanic conditions, resembling the Tertiary subtropical climate, consistently presented higher values for all components of reproductive performance than those at the thermal and rainfall tolerance limits. In support of our second hypothesis, the variation in reproductive performance among populations was primarily accounted for by local environmental conditions. Leaf traits, however, also explained reproductive variation but to a lesser extent. Finally, we found that small changes in tree size may cause large differences in reproductive performance. This close relationship between tree size and reproductive performance suggests that any impact on population size structure would likely jeopardize persistence and expansion at the range edge. Our results suggest that reproductive performance of wild olive trees was not shaped by the population geographic position within the species range, but by the interaction between local environment, as the main driver, and individual phenotypic traits.

  4. Performance analysis of 2D asynchronous hard-limiting optical code-division multiple access system through atmospheric scattering channel

    Science.gov (United States)

    Zhao, Yaqin; Zhong, Xin; Wu, Di; Zhang, Ye; Ren, Guanghui; Wu, Zhilu

    2013-09-01

    Optical code-division multiple access (OCDMA) systems usually allocate orthogonal or quasi-orthogonal codes to the active users. When transmitting through atmospheric scattering channel, the coding pulses are broadened and the orthogonality of the codes is worsened. In truly asynchronous case, namely both the chips and the bits are asynchronous among each active user, the pulse broadening affects the system performance a lot. In this paper, we evaluate the performance of a 2D asynchronous hard-limiting wireless OCDMA system through atmospheric scattering channel. The probability density function of multiple access interference in truly asynchronous case is given. The bit error rate decreases as the ratio of the chip period to the root mean square delay spread increases and the channel limits the bit rate to different levels when the chip period varies.

  5. Wireless Physical Layer Security: On the Performance Limit of Secret-Key Agreement

    KAUST Repository

    Zorgui, Marwen

    2015-05-01

    Physical layer security (PLS) is a new paradigm aiming at securing communications between legitimate parties at the physical layer. Conventionally, achieving confidentiality in communication networks relies on cryptographic techniques such as public-key cryptography, secret-key distribution and symmetric encryption. Such techniques are deemed secure based on the assumption of limited computational abilities of a wiretapper. Given the relentless progress in computational capacities and the dynamic topology and proliferation of modern wireless networks, the relevance of the previous techniques in securing communications is more and more questionable and less and less reliable. In contrast to this paradigm, PLS does not assume a specific computational power at any eavesdropper, its premise to guarantee provable security via employing channel coding techniques at the physical layer exploiting the inherent randomness in most communication systems. In this dissertation, we investigate a particular aspect of PLS, which is secret-key agreement, also known as secret-sharing. In this setup, two legitimate parties try to distill a secret-key via the observation of correlated signals through a noisy wireless channel, in the presence of an eavesdropper who must be kept ignorant of the secret-key. Additionally, a noiseless public channel is made available to the legitimate parties to exchange public messages that are also accessible to the eavesdropper. Recall that key agreement is an important aspect toward realizing secure communications in the sense that the key can be used in a one-time pad scheme to send the confidential message. In the first part, our focus is on secret-sharing over Rayleigh fading quasi-static channels. We study the fundamental relationship relating the probability of error and a given target secret-key rate in the high power regime. This is characterized through the diversity multiplexing tradeoff (DMT) concept, that we define for our model and then

  6. Assessing control of postural stability in community-living older adults using performance-based limits of stability

    Directory of Open Access Journals (Sweden)

    Boissy Patrick

    2008-03-01

    Full Text Available Abstract Background Balance disability measurements routinely used to identify fall risks in frail populations have limited value in the early detection of postural stability deficits in community-living older adults. The objectives of the study were to 1 measure performance-based limits of stability (LOS in community-living older adults and compare them to theoretical LOS computed from data proposed by the Balance Master® system, 2 explore the feasibility of a new measurement approach based on the assessment of postural stability during weight-shifting tasks at performance-based LOS, 3 quantify intra-session performance variability during multiple trials using the performance-based LOS paradigm. Methods Twenty-four healthy community-living older adults (10 men, 14 women aged between 62 to 85 (mean age ± sd, 71.5 ± 6 yrs participated in the study. Subjects' performance-based LOS were established by asking them to transfer their body weight as far as possible in three directions (forward, right and left without changing their base of support. LOS were computed as the maximal excursion of the COP in each direction among three trials. Participants then performed two experimental tasks that consisted in controlling, with the assistance of visual feedback, their centre of pressure (COP within two predefined targets set at 100% of their performance-based LOS. For each tasks 8 trials were performed. Ground reaction forces and torques during performance-based LOS evaluation and experimental tasks were recorded with a force plate. Sway area and medio-lateral mean COP displacement speed variables were extracted from force plate recordings. Results Significant differences between theoretical LOS computed from maximum leaning angles derived from anthropometric characteristics and performance-based LOS were observed. Results showed that a motor learning effect was present as the participants optimized their weight-shifting strategy through the first three

  7. Elucidating the Performance Limitations of Lithium-ion Batteries due to Species and Charge Transport through Five Characteristic Parameters

    Science.gov (United States)

    Jiang, Fangming; Peng, Peng

    2016-01-01

    Underutilization due to performance limitations imposed by species and charge transports is one of the key issues that persist with various lithium-ion batteries. To elucidate the relevant mechanisms, two groups of characteristic parameters were proposed. The first group contains three characteristic time parameters, namely: (1) te, which characterizes the Li-ion transport rate in the electrolyte phase, (2) ts, characterizing the lithium diffusion rate in the solid active materials, and (3) tc, describing the local Li-ion depletion rate in electrolyte phase at the electrolyte/electrode interface due to electrochemical reactions. The second group contains two electric resistance parameters: Re and Rs, which represent respectively, the equivalent ionic transport resistance and the effective electronic transport resistance in the electrode. Electrochemical modeling and simulations to the discharge process of LiCoO2 cells reveal that: (1) if te, ts and tc are on the same order of magnitude, the species transports may not cause any performance limitations to the battery; (2) the underlying mechanisms of performance limitations due to thick electrode, high-rate operation, and large-sized active material particles as well as effects of charge transports are revealed. The findings may be used as quantitative guidelines in the development and design of more advanced Li-ion batteries. PMID:27599870

  8. Modeling and Validation of Performance Limitations for the Optimal Design of Interferometric and Intensity-Modulated Fiber Optic Displacement Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Erik A. [Los Alamos National Laboratory

    2012-06-07

    -modulated interferometric sensor depends on an appropriate performance function (e.g., desired displacement range, accuracy, robustness, etc.). In this dissertation, the performance limitations of a bundled differential intensity-modulated displacement sensor are analyzed, where the bundling configuration has been designed to optimize performance. The performance limitations of a white light Fabry-Perot displacement sensor are also analyzed. Both these sensors are non-contacting, but they have access to different regions of the performance-space. Further, both these sensors have different degrees of sensitivity to experimental uncertainty. Made in conjunction with careful analysis, the decision of which sensor to deploy need not be an uninformed one.

  9. Flight mechanics and control of escape manoeuvres in hummingbirds. II. Aerodynamic force production, flight control and performance limitations.

    Science.gov (United States)

    Cheng, Bo; Tobalske, Bret W; Powers, Donald R; Hedrick, Tyson L; Wang, Yi; Wethington, Susan M; Chiu, George T-C; Deng, Xinyan

    2016-11-15

    The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of the manoeuvring performance of hummingbirds: (1) muscle mechanical power output and (2) delays in the neural sensing and control system. We focused on the magnificent hummingbird (Eugenes fulgens, 7.8 g) and the black-chinned hummingbird (Archilochus alexandri, 3.1 g), which represent large and small species, respectively. We first estimated the aerodynamic forces, moments and the mechanical power of escape manoeuvres using measured wing kinematics. Comparing active-manoeuvring and passive-damping aerodynamic moments, we found that pitch dynamics were lightly damped and dominated by the effect of inertia, while roll dynamics were highly damped. To achieve observed closed-loop performance, pitch manoeuvres required faster sensorimotor transduction, as hummingbirds can only tolerate half the delay allowed in roll manoeuvres. Accordingly, our results suggested that pitch control may require a more sophisticated control strategy, such as those based on prediction. For the magnificent hummingbird, we estimated that escape manoeuvres required muscle mass-specific power 4.5 times that during hovering. Therefore, in addition to the limitation imposed by sensorimotor delays, muscle power could also limit the performance of escape manoeuvres. © 2016. Published by The Company of Biologists Ltd.

  10. BER Performance Simulation of Generalized MC DS-CDMA System with Time-Limited Blackman Chip Waveform

    Directory of Open Access Journals (Sweden)

    I. Develi

    2010-09-01

    Full Text Available Multiple access interference encountered in multicarrier direct sequence-code division multiple access (MC DS-CDMA is the most important difficulty that depends mainly on the correlation properties of the spreading sequences as well as the shape of the chip waveforms employed. In this paper, bit error rate (BER performance of the generalized MC DS-CDMA system that employs time-limited Blackman chip waveform is presented for Nakagami-m fading channels. Simulation results show that the use of Blackman chip waveform can improve the BER performance of the generalized MC DS-CDMA system, as compared to the performances achieved by using timelimited chip waveforms in the literature.

  11. Parameter design and performance simulation of a 10 kV voltage compensation type active superconducting fault current limiter

    International Nuclear Information System (INIS)

    Chen, L.; Tang, Y.J.; Song, M.; Shi, J.; Ren, L.

    2013-01-01

    Highlights: •For a practical 10 kV system, the 10 kV active SFCL’s basic parameters are designed. •Under different fault conditions, the 10 kV active SFCL’s performances are simulated. •The designed 10 kV active SFCL’s engineering feasibility is discussed preliminarily. -- Abstract: Since the introduction of superconducting fault current limiter (SFCL) into electrical distribution system may be a good choice with economy and practicability, the parameter design and current-limiting characteristics of a 10 kV voltage compensation type active SFCL are studied in this paper. Firstly, the SFCL’s circuit structure and operation principle are presented. Then, taking a practical 10 kV distribution system as its application object, the SFCL’s basic parameters are designed to meet the system requirements. Further, using MATLAB, the detailed current-limiting performances of the 10 kV active SFCL are simulated under different fault conditions. The simulation results show that the active SFCL can deal well with the faults, and the parameter design’s suitability can be testified. At the end, in view of the engineering feasibility of the 10 kV active SFCL, some preliminary discussions are carried out

  12. Between Action and Act: On the 9-N in Catalonia’s and the Limits of Performativity

    Directory of Open Access Journals (Sweden)

    Begonya Sáez Tajafuerce

    2017-07-01

    Full Text Available By referring to Michel Foucault’s and Jacques Lacan’s works, and also taking as reference the popular consultation which took place in Cataluña on november 9th 2014, the purpose of this article is to draw the limits of Judith Butler’s theory of performativity with respect to the subject of the political and its agency. Those limits are made manifest by the distinction between political action and act or between subversion, understood as a transgression of the norm which gives place to the reconfiguration of the socio-symbolic order, and interruption, understood as a transgression of the norm which constitutes an event of a radically different order.

  13. Performance evaluation of five Mediterranean species to optimize ecosystem services of green roofs under water-limited conditions.

    Science.gov (United States)

    Azeñas, V; Janner, I; Medrano, H; Gulías, J

    2018-04-15

    Rapid urban growth in Mediterranean cities has become a serious environmental concern. Due to this expansion, which covers adjacent horizontal ground, a critical deficit of green areas has been increasing. Moreover, irrigation is considered an important issue since water is one of the most limiting natural resources all over the world. The main objective of this study was to perform a long-term experiment to assess five Mediterranean species for extensive green roof implementation in Mediterranean-climate conditions. Brachypodium phoenicoides, Crithmum maritimum, Limonium virgatum, Sedum sediforme and Sporobolus pungens were grown in experimental modules under well-watered and water-limited conditions (irrigation at 50% and 25% ET 0 , respectively). Plant growth and cover, relative appearance, color evolution and water use were determined periodically for two years. Shoot and root biomass were quantified at the end of the experimental period. The effects of the irrigation treatments and seasonal changes were assessed to identify the advantages and disadvantages of each species according to their environmental performance. All species survived and showed adequate esthetic performance and plant cover during the experiment. S. sediforme registered the lowest variation of relative appearance along the experiment, the highest biomass production and the lowest water consumption. Nevertheless, B. phoenicoides appeared to be an interesting alternative to S. sediforme, showing high esthetic performance and water consumption throughout the rainy season, suggesting a potential role of this species in stormwater regulation related with runoff reduction. S. pungens performed well in summer but presented poor esthetics during winter. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Development of stair-climbing mechanism with passive crawlers. Analysis of limitation for crawler rotation angle and test vehicle performance

    International Nuclear Information System (INIS)

    Hirasawa, Junji; Kimura, Tetsuya

    2016-01-01

    This paper describes a novel mechanism with passive crawlers that will realize a stair-climbing rescue robot with simple system. The proposed mechanism is called 'SMART-III', it is named after 'Simple Mechanism Adaptive for Rough Terrain'. Some quasi-static dynamic analysis were implemented and effectiveness of limitation for crawler rotation angle were verified. A prototype robot with the SMART-III mechanism had been improved. Experimental results show the effectiveness and performance of the proposed mechanism against a step and continuous stairs. (author)

  15. Performance evaluation of multilevel modulation formats using partial response for capacity upgrade in access network with limited electronic bandwidth

    DEFF Research Database (Denmark)

    Madsen, Peter; Suhr, Lau Frejstrup; Rodríguez Páez, Juan Sebastián

    2016-01-01

    We present a successful experimental evaluation of 4 level Pulse Amplitude Modulation (4-PAM) and Duobinary modulation. An experimental performance evaluation is presented for Duobinary 4 PAM and other modulation formats. All modulation formants used, may be considered to be implemented in future...... Passive Optical Network (PON) class access networks with limited electrical bandwidth. We compared NRZ, Duobinary, 4-PAM and Duobinary 4-PAM operating at 9 Gbaud over 20 km single mode fiber. The results provides an insight and guidelines on the utilization of these advanced modulation formats....

  16. The performance and limitations of FPGA-based digital servos for atomic, molecular, and optical physics experiments.

    Science.gov (United States)

    Yu, Shi Jing; Fajeau, Emma; Liu, Lin Qiao; Jones, David J; Madison, Kirk W

    2018-02-01

    In this work, we address the advantages, limitations, and technical subtleties of employing field programmable gate array (FPGA)-based digital servos for high-bandwidth feedback control of lasers in atomic, molecular, and optical physics experiments. Specifically, we provide the results of benchmark performance tests in experimental setups including noise, bandwidth, and dynamic range for two digital servos built with low and mid-range priced FPGA development platforms. The digital servo results are compared to results obtained from a commercially available state-of-the-art analog servo using the same plant for control (intensity stabilization). The digital servos have feedback bandwidths of 2.5 MHz, limited by the total signal latency, and we demonstrate improvements beyond the transfer function offered by the analog servo including a three-pole filter and a two-pole filter with phase compensation to suppress resonances. We also discuss limitations of our FPGA-servo implementation and general considerations when designing and using digital servos.

  17. The performance and limitations of FPGA-based digital servos for atomic, molecular, and optical physics experiments

    Science.gov (United States)

    Yu, Shi Jing; Fajeau, Emma; Liu, Lin Qiao; Jones, David J.; Madison, Kirk W.

    2018-02-01

    In this work, we address the advantages, limitations, and technical subtleties of employing field programmable gate array (FPGA)-based digital servos for high-bandwidth feedback control of lasers in atomic, molecular, and optical physics experiments. Specifically, we provide the results of benchmark performance tests in experimental setups including noise, bandwidth, and dynamic range for two digital servos built with low and mid-range priced FPGA development platforms. The digital servo results are compared to results obtained from a commercially available state-of-the-art analog servo using the same plant for control (intensity stabilization). The digital servos have feedback bandwidths of 2.5 MHz, limited by the total signal latency, and we demonstrate improvements beyond the transfer function offered by the analog servo including a three-pole filter and a two-pole filter with phase compensation to suppress resonances. We also discuss limitations of our FPGA-servo implementation and general considerations when designing and using digital servos.

  18. Analytical performance, reference values and decision limits. A need to differentiate between reference intervals and decision limits and to define analytical quality specifications

    DEFF Research Database (Denmark)

    Petersen, Per Hyltoft; Jensen, Esther A; Brandslund, Ivan

    2012-01-01

    of the values of analytical components measured on reference samples from reference individuals. Decision limits are based on guidelines from national and international expert groups defining specific concentrations of certain components as limits for decision about diagnosis or well-defined specific actions....... Analytical quality specifications for reference intervals have been defined for bias since the 1990s, but in the recommendations specified in the clinical guidelines analytical quality specifications are only scarcely defined. The demands for negligible biases are, however, even more essential for decision...... limits, as the choice is no longer left to the clinician, but emerge directly from the concentration. Even a small bias will change the number of diseased individuals, so the demands for negligible biases are obvious. A view over the analytical quality as published gives a variable picture of bias...

  19. Revisiting Pocos de Caldas. Application of the co-precipitation approach to establish realistic solubility limits for performance assessment

    International Nuclear Information System (INIS)

    Bruno, J.; Duro, L.; Jordana, S.; Cera, E.

    1996-02-01

    Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs

  20. Revisiting Pocos de Caldas. Application of the co-precipitation approach to establish realistic solubility limits for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Duro, L.; Jordana, S.; Cera, E. [QuantiSci, Barcelona (Spain)

    1996-02-01

    Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs.

  1. Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lei, E-mail: stclchen1982@163.com [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui [School of Electrical Engineering, Wuhan University, Wuhan 430072 (China); Zhu, Lin [Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville 37996 (United States); Guo, Fang [Department of Substation, Guang Dong Electric Power Design Institute, Guangzhou 510663 (China)

    2015-11-15

    Highlights: • A modified flux-coupling type SFCL is suggested to enhance the transient performance of a micro-grid. • The SFCL’s main contribution is to improve the micro-grid’s fault ride-through capability. • The SFCL also can make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. • The simulations show that the SFCL can availably strengthen the micro-grid’s voltage and frequency stability. - Abstract: Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid’s operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid’s fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL’s contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

  2. Application of a modified flux-coupling type superconducting fault current limiter to transient performance enhancement of micro-grid

    International Nuclear Information System (INIS)

    Chen, Lei; Zheng, Feng; Deng, Changhong; Li, Shichun; Li, Miao; Liu, Hui; Zhu, Lin; Guo, Fang

    2015-01-01

    Highlights: • A modified flux-coupling type SFCL is suggested to enhance the transient performance of a micro-grid. • The SFCL’s main contribution is to improve the micro-grid’s fault ride-through capability. • The SFCL also can make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. • The simulations show that the SFCL can availably strengthen the micro-grid’s voltage and frequency stability. - Abstract: Concerning the application and development of a micro-grid system which is designed to accommodate high penetration of intermittent renewable resources, one of the main issues is related to an increase in the fault-current level. It is crucial to ensure the micro-grid’s operational stability and service reliability when a fault occurs in the main network. In this paper, our research group suggests a modified flux-coupling type superconducting fault current limiter (SFCL) to enhance the transient performance of a typical micro-grid system. The SFCL is installed at the point of common coupling (PCC) between the main network and the micro-grid, and it is expected to actively improve the micro-grid’s fault ride-through capability. And for some specific faults, the micro-grid should disconnect from the main network, and the SFCL’s contribution is to make the micro-grid carry out a smooth transition between its grid-connected and islanded modes. Related theory derivation, technical discussion and simulation analysis are performed. From the demonstrated results, applying the SFCL can effectively limit the fault current, maintain the power balance, and enhance the voltage and frequency stability of the micro-grid.

  3. Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

    Science.gov (United States)

    Castro-Santos, Theodore; Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge

    2013-01-01

    Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

  4. THE CHALLENGES OF CORPORATE GOVERNANCE AND AUDIT IN RELATION TO FINANCIAL PERFORMANCE – TRENDS, LIMITATIONS AND DIRECTIONS TO FOLLOW

    Directory of Open Access Journals (Sweden)

    Alexandra Narcisa CIOBAN (LUCAN

    2016-12-01

    Full Text Available Through this paper we propose to identify and present the latest trends in valuing the corporate governance and audit features in relation to the company performance, measured in financial terms. Our research is qualitative, as it covers a wide range of approache from the perspective of academics and practitioners in the field. In this regard, we consulted the most important resources in the world scientific electronic documentation, such as: Thomson Reuters Web of Science, SpringerLink platform, PROQUEST Central, Oxford Journals, Emerald Journals and other research platforms. The contribution of this research it is valuable both for researchers in the area of financial accounting and practitioners, and aims to identify the recent challenges of the corporate governance and audit in influencing the financial performance of major companies around the world. We analyzed a variety of scientific publications on this subject, more than 70 empirical studies conducted in the US, China, Russia, Japan, India, Malaysia, the Arab countries, UK, Germany, Spain, Romania, etc. After having conducted the research, we carried out a platform with representative variables for corporate governance, audit and financial performance which will serve for future studies in the field. This will facilitate the researchers’ choice for building econometric analysis models since we also surprised existing limitations.

  5. Growth Performance and Carcass Characteristics of Korean Native Ducks Fed Diets with Varying Levels of Limiting Amino Acids

    Directory of Open Access Journals (Sweden)

    Y. K. Choo

    2014-04-01

    Full Text Available There are multiple experiments conducted with male Korean native ducks (KND to evaluate the optimal levels of limiting amino acids (AA. In Exp. 1, a total of 450 one-d-old male KNDs were divided into five groups with six replicates and fed experimental diets with varying levels of lysine, total sulfur amino acids (TSAA and threonine (T1, 0.90/0.74/0.70%; T2, 1.00/0.82/0.77%; T3, 1.10/0.90/0.85%; T4, 1.20/0.98/0.93%; T5, 1.30/1.07/1.01% to 21 d of age. In Exp. 2, one-d-old male KND were received and fed commercial starter diet from hatching to 21 d of age, and then divided into five groups with six replicates and fed one of five diets varying levels of lysine, TSAA, and threonine (T1, 0.73/0.62/0.54%; T2, 0.80/0.68/0.60%; T3, 0.87/0.74/0.65%; T4, 0.94/0.80/0.70%; T5, 1.01/0.86/0.75% during 22 to 56 d of age, respectively. The BW gain was linearly increased as dietary limiting AA levels increased to 1.20% lysine, 0.98% TSAA and 0.93% threonine. There were no significant differences in feed intake, gain:feed and uniformity among groups. In Exp. 2, the BW gain and gain:feed were not affected by dietary limiting AA levels. There were no significant differences in carcass characteristics and meat quality among groups. The growth performance and carcass characteristics did not show the significant response to increasing dietary limiting AA levels in KND during 22 to 56 d of age. In conclusion, the levels of lysine, TSAA and threonine necessary to maximize growth for starter phase were at least 1.20%, 0.98%, and 0.93%, respectively. On the other hands, KND require relatively low levels of limiting AA for late growth and carcass yield. The dietary levels of 0.73% lysine, 0.62% TSAA and 0.54% threonine appear to be adequate during growing phase.

  6. Nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance in the diatom Phaeodactylum tricornutum

    Science.gov (United States)

    Li, W.; Gao, K.; Beardall, J.

    2015-04-01

    It has been proposed that ocean acidification (OA) will interact with other environmental factors to influence the overall impact of global change on biological systems. Accordingly we investigated the influence of nitrogen limitation and OA on the physiology of diatoms by growing the diatom Phaeodactylum tricornutum Bohlin under elevated (1000 μatm; high CO2 - HC) or ambient (390 μatm; low CO2 - LC) levels of CO2 with replete (110 μmol L-1; high nitrate - HN) or reduced (10 μmol L-1; low nitrate - LN) levels of NO3- and subjecting the cells to solar radiation with or without UV irradiance to determine their susceptibility to UV radiation (UVR, 280-400 nm). Our results indicate that OA and UVB induced significantly higher inhibition of both the photosynthetic rate and quantum yield under LN than under HN conditions. UVA or/and UVB increased the cells' non-photochemical quenching (NPQ) regardless of the CO2 levels. Under LN and OA conditions, activity of superoxide dismutase and catalase activities were enhanced, along with the highest sensitivity to UVB and the lowest ratio of repair to damage of PSII. HC-grown cells showed a faster recovery rate of yield under HN but not under LN conditions. We conclude therefore that nutrient limitation makes cells more prone to the deleterious effects of UV radiation and that HC conditions (ocean acidification) exacerbate this effect. The finding that nitrate limitation and ocean acidification interact with UV-B to reduce photosynthetic performance of the diatom P. tricornutum implies that ocean primary production and the marine biological C pump will be affected by OA under multiple stressors.

  7. Predicting Classifier Performance with Limited Training Data: Applications to Computer-Aided Diagnosis in Breast and Prostate Cancer

    Science.gov (United States)

    Basavanhally, Ajay; Viswanath, Satish; Madabhushi, Anant

    2015-01-01

    Clinical trials increasingly employ medical imaging data in conjunction with supervised classifiers, where the latter require large amounts of training data to accurately model the system. Yet, a classifier selected at the start of the trial based on smaller and more accessible datasets may yield inaccurate and unstable classification performance. In this paper, we aim to address two common concerns in classifier selection for clinical trials: (1) predicting expected classifier performance for large datasets based on error rates calculated from smaller datasets and (2) the selection of appropriate classifiers based on expected performance for larger datasets. We present a framework for comparative evaluation of classifiers using only limited amounts of training data by using random repeated sampling (RRS) in conjunction with a cross-validation sampling strategy. Extrapolated error rates are subsequently validated via comparison with leave-one-out cross-validation performed on a larger dataset. The ability to predict error rates as dataset size increases is demonstrated on both synthetic data as well as three different computational imaging tasks: detecting cancerous image regions in prostate histopathology, differentiating high and low grade cancer in breast histopathology, and detecting cancerous metavoxels in prostate magnetic resonance spectroscopy. For each task, the relationships between 3 distinct classifiers (k-nearest neighbor, naive Bayes, Support Vector Machine) are explored. Further quantitative evaluation in terms of interquartile range (IQR) suggests that our approach consistently yields error rates with lower variability (mean IQRs of 0.0070, 0.0127, and 0.0140) than a traditional RRS approach (mean IQRs of 0.0297, 0.0779, and 0.305) that does not employ cross-validation sampling for all three datasets. PMID:25993029

  8. Efficiencies and coefficients of performance of heat engines, refrigerators, and heat pumps with friction: a universal limiting behavior.

    Science.gov (United States)

    Bizarro, João P S; Rodrigues, Paulo

    2012-11-01

    For work-producing heat engines, or work-consuming refrigerators and heat pumps, the percentage decrease caused by friction in their efficiencies, or coefficients of performance (COP's), is approximately given by the ratio W(fric)/W between the work spent against friction forces and the work performed by, or delivered to, the working fluid. This universal scaling, which applies in the limit of small friction (W(fric)/W heat-engine efficiencies), allows a simple and quick estimate of the impact that friction losses can have on the FOM's of thermal engines and plants, or of the level of those losses from the observed and predicted FOM's. In the case of refrigerators and heat pumps, if W(fric)/W heat engines), the COP percentage decrease due to friction approaches asymptotically (W(fric)/W)/(1+W(fric)/W) instead of W(fric)/W. Estimates for the level of frictional losses using the Carnot (or, for heat engines and power plants only, the Curzon-Ahlborn) predictions and observed FOM's of real power plants, heat engines, refrigerators, and heat pumps show that they usually operate in domains where these behaviors are valid.

  9. Effect of High Phytase Inclusion Rates on Performance of Broilers Fed Diets Not Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    T. T. dos Santos

    2013-02-01

    Full Text Available Phytate is not only an unavailable source of phosphorus (P for broilers but it also acts as an anti-nutrient, reducing protein and mineral absorption, increasing endogenous losses and reducing broiler performance. The objective of this study was to investigate the anti-nutritional effects of phytate by including high levels of phytase in diets not severely limited in available P. A total of 768 male Arbor Acres broilers were distributed in six treatments of eight replicate pens of 16 birds each consisting of a positive control diet (PC, positive control with 500 FTU/kg phytase, negative control (NC diet with lower available P and calcium (Ca levels and the same NC diet with 500, 1,000 or 1,500 FTU/kg phytase. Body weight gain (BWG, feed intake (FI, feed conversion ratio (FCR and mortality were determined at 21 and 35 d of age while foot ash was determined in four birds per pen at 21 d of age. FI, FCR and foot ash where not affected by the lower mineral diets at 21 d of age nor by the enzyme inclusion but broilers fed lower Ca and available P diets had lower BWG. At 35 d of age no difference was observed between broilers fed the positive or NC diets but broilers fed 500, 1,000 and 1,500 FTU/kg on top of the NC diet had better FCR than broilers fed the positive control diet. When compared to birds fed a diet adequate in P, birds fed the same diet included with 500, 1,000 and 1,500 FTU/kg of phytase in marginally deficient available P and Ca diets had an improvement of performance. These results support the concept that hydrolysing phytate and reducing the anti-nutritional effects of phytate improves bird performance on marginally deficient diets that were not covering the P requirement of birds.

  10. 'The engine just started coughing!' - Limits of physical performance, aging and career continuity in elite endurance sports.

    Science.gov (United States)

    Ronkainen, Noora J; Ryba, Tatiana V; Nesti, Mark S

    2013-12-01

    This research examines male endurance athletes' experience of aging and/or reaching the perceived limits of physical performance. More specifically, the current study aimed to explore how existential meanings attached to these experiences are connected with athletes' decision-making concerning career continuity and retirement. Life story interviews were conducted with 10 Finnish runners and/or orienteers aged between 25 and 62 and the data was analyzed with an existential-narrative framework. Four major storylines related to aging were identified: The end of an era, putting things in perspective, the attitude has to change and winning was never the only motive. Our results suggest that endurance athletes possess diverse ways of bringing meaning to the experience of aging, both confirming and resisting the dominant cultural narrative of decline. While three athletes' stories confirmed the normativity of retirement when unable to improve their results anymore, other athletes demonstrated career continuity and positive aspects in the late career years, such as lack of competitive anxiety, finding perspective and increased enjoyment in running. We suggest that through awareness of alternative narratives, sport psychology consultants may be able to help their clients to explore new meanings in the potentially challenging and beneficial experiences of aging and athletic retirement. © 2013.

  11. Sensitivity and uncertainty analyses applied to one-dimensional radionuclide transport in a layered fractured rock: Evaluation of the Limit State approach, Iterative Performance Assessment, Phase 2

    International Nuclear Information System (INIS)

    Wu, Y.T.; Gureghian, A.B.; Sagar, B.; Codell, R.B.

    1992-12-01

    The Limit State approach is based on partitioning the parameter space into two parts: one in which the performance measure is smaller than a chosen value (called the limit state), and the other in which it is larger. Through a Taylor expansion at a suitable point, the partitioning surface (called the limit state surface) is approximated as either a linear or quadratic function. The success and efficiency of the limit state method depends upon choosing an optimum point for the Taylor expansion. The point in the parameter space that has the highest probability of producing the value chosen as the limit state is optimal for expansion. When the parameter space is transformed into a standard Gaussian space, the optimal expansion point, known as the lost Probable Point (MPP), has the property that its location on the Limit State surface is closest to the origin. Additionally, the projections onto the parameter axes of the vector from the origin to the MPP are the sensitivity coefficients. Once the MPP is determined and the Limit State surface approximated, formulas (see Equations 4-7 and 4-8) are available for determining the probability of the performance measure being less than the limit state. By choosing a succession of limit states, the entire cumulative distribution of the performance measure can be detemined. Methods for determining the MPP and also for improving the estimate of the probability are discussed in this report

  12. Advantages and Limitations of Androgen Receptor-Based Methods for Detecting Anabolic Androgenic Steroid Abuse as Performance Enhancing Drugs

    Science.gov (United States)

    Bailey, Kathy; Yazdi, Tahmineh; Masharani, Umesh; Tyrrell, Blake; Butch, Anthony; Schaufele, Fred

    2016-01-01

    Testosterone (T) and related androgens are performance enhancing drugs (PEDs) abused by some athletes to gain competitive advantage. To monitor unauthorized androgen abuse, doping control programs use mass spectrometry (MS) to detect androgens, synthetic anabolic-androgenic steroids (AASs) and their metabolites in an athlete’s urine. AASs of unknown composition will not be detected by these procedures. Since AASs achieve their anabolic effects by activating the Androgen Receptor (AR), cell-based bioassays that measure the effect of a urine sample on AR activity are under investigation as complementary, pan-androgen detection methods. We evaluated an AR BioAssay as a monitor for androgen activity in urine pre-treated with glucuronidase, which releases T from the inactive T-glucuronide that predominates in urine. AR BioAssay activity levels were expressed as ‘T-equivalent’ concentrations by comparison to a T dose response curve. The T-equivalent concentrations of androgens in the urine of hypogonadal participants supplemented with T (in whom all androgenic activity should arise from T) were quantitatively identical to the T measurements conducted by MS at the UCLA Olympic Analytical Laboratory (0.96 ± 0.22). All 17 AASs studied were active in the AR BioAssay; other steroids were inactive. 12 metabolites of 10 commonly abused AASs, which are used for MS monitoring of AAS doping because of their prolonged presence in urine, had reduced or no AR BioAssay activity. Thus, the AR BioAssay can accurately and inexpensively monitor T, but its ability to monitor urinary AASs will be limited to a period immediately following doping in which the active AASs remain intact. PMID:26998755

  13. The effect of performance-volume limit on the DRG based acute care hospital financing in Hungary.

    Science.gov (United States)

    Endrei, Dóra; Zemplényi, Antal; Molics, Bálint; Agoston, István; Boncz, Imre

    2014-04-01

    The aim of our paper is to analyse the effect of the so-called performance volume limit (PVL) financing method on acute hospital care. The data were derived from the nationwide administrative dataset of the National Health Insurance Fund Administration (OEP) covering the period 2003-2008. We analysed the trends in the DRG cost-weights, number of cases, case-mix, and average length of stay. We calculated the average annual reimbursement rate per DRG cost-weight with and without the application of PVL degression according to the hospital type and medical professions. Our results showed that although the national case mix (i.e., the sum of all of the DRG cost-weights produced in one year) did not change between 2003-2006, the trend of the annual number of cases increased, and the average length of stay decreased. During 2007-2008, a significant decline was found in each indicator. The introduction of the PVL resulted in a health insurance budget saving of 1.9% in 2004, 2.6% in 2005, 3.4% in 2006, 5.6% in 2007, and 3.2% in 2008. We found the lowest reimbursement rate per DRG cost-weight at the university medical schools (HUF 138,200 or € 550) and children's hospitals (HUF 132,547 or € 528), whereas the highest was at the county hospitals (HUF 143,451 or € 571) and city hospitals (HUF 142, 082 or € 565). The implementation of the PVL reduced the acute care hospital activity and reimbursement. The effect of the PVL was different on the different types of hospitals, and it had a serious disadvantageous effect on the university medical schools and children's hospitals. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Advantages and Limitations of Androgen Receptor-Based Methods for Detecting Anabolic Androgenic Steroid Abuse as Performance Enhancing Drugs.

    Science.gov (United States)

    Bailey, Kathy; Yazdi, Tahmineh; Masharani, Umesh; Tyrrell, Blake; Butch, Anthony; Schaufele, Fred

    2016-01-01

    Testosterone (T) and related androgens are performance enhancing drugs (PEDs) abused by some athletes to gain competitive advantage. To monitor unauthorized androgen abuse, doping control programs use mass spectrometry (MS) to detect androgens, synthetic anabolic-androgenic steroids (AASs) and their metabolites in an athlete's urine. AASs of unknown composition will not be detected by these procedures. Since AASs achieve their anabolic effects by activating the Androgen Receptor (AR), cell-based bioassays that measure the effect of a urine sample on AR activity are under investigation as complementary, pan-androgen detection methods. We evaluated an AR BioAssay as a monitor for androgen activity in urine pre-treated with glucuronidase, which releases T from the inactive T-glucuronide that predominates in urine. AR BioAssay activity levels were expressed as 'T-equivalent' concentrations by comparison to a T dose response curve. The T-equivalent concentrations of androgens in the urine of hypogonadal participants supplemented with T (in whom all androgenic activity should arise from T) were quantitatively identical to the T measurements conducted by MS at the UCLA Olympic Analytical Laboratory (0.96 ± 0.22). All 17 AASs studied were active in the AR BioAssay; other steroids were inactive. 12 metabolites of 10 commonly abused AASs, which are used for MS monitoring of AAS doping because of their prolonged presence in urine, had reduced or no AR BioAssay activity. Thus, the AR BioAssay can accurately and inexpensively monitor T, but its ability to monitor urinary AASs will be limited to a period immediately following doping in which the active AASs remain intact.

  15. Prediction of Mobility Limitations after Hospitalization in Older Medical Patients by Simple Measures of Physical Performance Obtained at Admission to the Emergency Department

    DEFF Research Database (Denmark)

    Bodilsen, Ann Christine; Hedegaard Klausen, Henrik; Petersen, Janne

    2016-01-01

    Objective: Mobility limitations relate to dependency in older adults. Identification of older patients with mobility limitations after hospital discharge may help stratify treatment and could potentially counteract dependency seen in older adults after hospitalization. We investigated the ability...... of four physical performance measures administered at hospital admission to identify older medical patients who manifest mobility limitations 30 days after discharge. Design: Prospective cohort study of patients (≥65 years) admitted to the emergency department for acute medical illness. During the first...... included. Of those, 128 (40%) patients had mobility limitations at follow-up. Univariate analyzes showed that each of the physical performance measures was strongly associated with mobility limitations at follow-up (handgrip strength(women), OR 0.86 (0.81–0.91), handgrip strength(men), OR 0.90 (0...

  16. Is math anxiety in the secondary classroom limiting physics mastery? A study of math anxiety and physics performance

    Science.gov (United States)

    Mercer, Gary J.

    This quantitative study examined the relationship between secondary students with math anxiety and physics performance in an inquiry-based constructivist classroom. The Revised Math Anxiety Rating Scale was used to evaluate math anxiety levels. The results were then compared to the performance on a physics standardized final examination. A simple correlation was performed, followed by a multivariate regression analysis to examine effects based on gender and prior math background. The correlation showed statistical significance between math anxiety and physics performance. The regression analysis showed statistical significance for math anxiety, physics performance, and prior math background, but did not show statistical significance for math anxiety, physics performance, and gender.

  17. Impact of steam generator start-up limitations on the performance of a parabolic trough solar power plant

    DEFF Research Database (Denmark)

    Ferruzza, Davide; Topel, Monika; Laumert, Björn

    2018-01-01

    typically start-up and shut down every day, so in order to maximize their profitability, it is necessary to increase their flexibility in transient operation and to initiate power generation as rapidly as possible. Two of the key components are the steam generator and steam turbine and the rates at which...... they can reach operational speed are limited by thermo-mechanical constraints. This paper presents an analysis of the effects of the thermal stress limitations of the steam generator and steam turbine on the power plant start-up, and quantifies their impact on the economy of the system. A dynamic model......-driven and peak-load. The results indicate that for steam generator hot start-ups, a 1.5% increase in peak-load electricity production would be achieved by doubling the maximum allowable heating rate of the evaporator. No useful increase would be achieved by increasing the rates beyond a limit of 7–8 K...

  18. On performance limitations and property correlations of Al-doped ZnO deposited by radio-frequency sputtering

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Ottsen, Tobias Sand; Stamate, Eugen

    2016-01-01

    -pressure regime, we find a generalized dependence of the electrical properties, grain size, texture, and Al content on compressive stress, regardless of sputtering pressure or position on the substrate. In a high-pressure regime, a porous microstructure limits the achievable resistivity and causes it to increase......The electrical properties of RF-sputtered Al-doped ZnO are often spatially inhomogeneous and strongly dependent on deposition parameters. In this work, we study the mechanisms that limit the minimum resistivity achievable under different deposition regimes. In a low- and intermediate...... over time as well. The primary cause of inhomogeneity in the electrical properties is identified as energetic particle bombardment. Inhomogeneity in oxygen content is also observed, but its effect on the electrical properties is small and limited to the carrier mobility....

  19. 25 CFR 12.55 - Are there any limits on how much force an officer can use when performing law enforcement duties?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Are there any limits on how much force an officer can use when performing law enforcement duties? 12.55 Section 12.55 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAW AND ORDER INDIAN COUNTRY LAW ENFORCEMENT Conduct § 12.55 Are there any limits on how much force an officer can use when...

  20. 40 CFR 197.36 - Are there limits on what DOE must consider in the performance assessments?

    Science.gov (United States)

    2010-07-01

    ... effects of climate change. The climate change analysis may be limited to the effects of increased water flow through the repository as a result of climate change, and the resulting transport and release of radionuclides to the accessible environment. The nature and degree of climate change may be represented by...

  1. Two-fluid limits on stellarator performance: Explanation of three stellarator puzzles and comparison to axisymmetric plasmas

    International Nuclear Information System (INIS)

    Sugiyama, L.E.; Strauss, H.R.; Park, W.; Fu, G.Y.; Breslau, J.A.; Chen, J.

    2005-01-01

    The basic two-fluid processes, those related to the nonlinearly self-consistent diamagnetic drifts of the electrons and ions, are shown to have fundamentally different effects on the steady state and beta limits of stellarator configurations, compared to MHD predictions. Nonlinear numerical simulation shows that the ideal MHD ballooning modes and the resistive MHD ballooning and interchange modes at relatively high mode numbers, that set the most severe theoretical limits on beta in stellarators with fixed boundary, are easily stabilized by two-fluid effects at realistic parameters, including finite Larmor radius effects related to the ion diamagnetic drift. Magnetic reconnection at low-order rational magnetic surfaces, on the other hand, is enhanced through the parallel component of the two-fluid electron pressure gradient in Ohm's law. The accelerated reconnection rates may impose the true intrinsic limit on beta in stellarators, as a 'soft' or confinement mediated limit in β e , due to steady confinement degradation in the presence of large magnetic islands. Study of the corresponding axisymmetric configurations shows that the helical component of the stellarator configuration provides an important amplifying factor for these effects. The two-fluid results may explain several previously puzzling experimental observations on stellarator behavior. (author)

  2. Modelling, development and optimization of integrated power LDMOS transistor. Performance limits in terms of energy; Modelisation, conception et optimisation de composant de puissance lateral DMOS integre. Etude des limites de performance en energie

    Energy Technology Data Exchange (ETDEWEB)

    Farenc, D.

    1997-12-16

    Technologies for Smart Power Integrated Circuits combine into a single chip Bipolar and CMOS transistors, plus power with lateral or vertical DMOS transistors. Complexity which has been increasing dramatically since the mid-80`s has allowed to integrate, into a single monolithic solution, entire systems. This thesis deals with the modelling, conception and test of the power integrated LDMOS transistor. The power LDMOS transistor is used as a switching device. It is characterized by two parameters which are the Specific On-resistance R{sub sp} and the breakdown voltage BV{sub DSS}. The LDMOS transistor developed for the new Smart Power technology exhibits a Specific On-resistance of 200 m{Omega}{sup *}mm{sup 2} and a breakdown voltage of 60 V. This device is dedicated to automotive applications. A reduction of the power device which is achieved with a low Specific On-resistance puts forward new issues such as the maximum Energy capability. When the power device is switched-off on an inductive load, a certain amount of energy is dissipated; if it is beyond a certain limit, the device is destroyed. Our goal is to determine the energy limits which are associated with our new Power integrated LDMOS transistor. (author) 28 refs.

  3. Feed intake limitation strategies for the growing rabbit: effect on feeding behaviour, welfare, performance, digestive physiology and health: a review.

    Science.gov (United States)

    Gidenne, T; Combes, S; Fortun-Lamothe, L

    2012-09-01

    This review aims to present the different effects produced by a post-weaning intake limitation strategy on the growing rabbit, now largely used by French professional rabbit breeders. Although a quantitative feed restriction leads to slower growth, feed conversion (FC) is improved, particularly when the rabbits are again fed freely, as compensatory growth occurs. This better FC or the healthy rabbit is because of better digestion resulting from slower passage through the intestine, whereas the digestive physiology is slightly modified (morphometry of the intestinal mucosa, fermentation pattern, microbiota). Meat quality and carcass characteristics are not greatly affected by feed restriction, except for a lower dressing-out percentage. One of the main advantages of limiting post-weaning intake of the rabbit is to reduce the mortality and morbidity rate due to digestive disorders (particularly epizootic rabbit enteropathy syndrome). The consequences for animal welfare are debatable, as feed restriction probably leads to hunger, but it reduces the incidence of digestive troubles after weaning. However, the growing rabbit adapts very well to an intake limitation strategy, without any aggressive behaviour for congener. In conclusion, restriction strategies could improve profitability of rabbit breeding, but they should be adapted to any specific breeding situation, according to the national market, feed prices, etc.

  4. On limits of Wireless Communications in a Fading Environment: a General Parameterization Quantifying Performance in Fading Channel

    Directory of Open Access Journals (Sweden)

    Amit Grover

    2014-08-01

    Full Text Available The reliable services along with high throughput can be achieved by using wireless communication systems. These systems also provides a wide coverage because of their features, no doubt MIMO Communication System [1] is one among them. Features provided by these systems ensure the improved system coverage and increased data transmission rate by considering multiple numbers of transmitter and receiver antennas. In this article, the concept of equalization has been considered and finally the performance of the MIMO Systems in Rician flat fading [5] channel is compared with the Rayleigh flat fading channel. It has also been observed that the performance of these Systems in Rician Flat Fading Channel is the best as compare to the Rayleigh Flat Fading Channel [10]. It has been concluded that the successive interference methods provide better performance as compare to others, but their complexity is high. Simulation results shows that ML provides the better performance in comparison to other equalizers but Sphere decoder provides the best performance.

  5. Evaluation of impact limiter performance during end-on and slapdown drop tests of a one-third scale model storage/transport cask system

    International Nuclear Information System (INIS)

    Yoshimura, H.R.; Bronowski, D.R.; Uncapher, W.L.; Attaway, S.W.; Bateman, V.I.; Carne, T.G.; Gregory, D.L.; Huerta, M.

    1990-12-01

    This report describes drop testing of a one-third scale model shipping cask system. Two casks were designed and fabricated by Transnuclear, Inc., to ship spent fuel from the former Nuclear Fuel Services West Valley reprocessing facility in New York to the Idaho National Engineering Laboratory for a long-term spent fuel dry storage demonstration project. As part of the NRC's regulatory certification process, one-third scale model tests were performed to obtain experimental data on impact limiter performance during impact testing. The objectives of the testing program were to (1) obtain deceleration and displacement information for the cask and impact limiter system, (2) obtain dynamic force-displacement data for the impact limiters, (3) verify the integrity of the impact limiter retention system, and (4) examine the crush behavior of the limiters. Two 30-ft (9-m) drop tests were conducted on a mass model of the cask body and scaled balsa and redwood-filled impact limiters. This report describes the results of both tests in terms of measured decelerations, posttest deformation measurements, and the general structural response of the system. 3 refs., 32 figs

  6. Summary of the half-day internal review of LHC performance limitations (linked to transverse collective effects) during run II (CERN, 29/11/2016)

    CERN Document Server

    Metral, Elias; Biancacci, Nicolo; Buffat, Xavier; Carver, Lee Robert; Iadarola, Giovanni; Li, Kevin Shing Bruce; Persson, Tobias Hakan Bjorn; Romano, Annalisa; Schenk, Michael; Tambasco, Claudia; CERN. Geneva. ATS Department

    2017-01-01

    In this note the half-day internal review of LHC performance limitations (linked to transverse collective effects) during run II (2015-2016), which took place at CERN on 29/11/2016 (https://indico.cern.ch/event/589625/), is summarised and the next steps are discussed.

  7. Physical Performance and Serum 25(OH)vitamin D Status in Community Dwelling Old Mobility Limited Adults: A Cross-Sectional Study.

    Science.gov (United States)

    von Berens, Å; Cederholm, T; Fielding, R A; Gustafsson, T; Kirn, D; Laussen, J; Nydahl, M; Travison, T G; Reid, K; Koochek, A

    2018-01-01

    To examine the potential association between serum 25(OH) vitamin D and the performance on the Short Physical Performance Battery (SPPB) including the sub-components; five repeated chair stands test, 4 meters walk test and balance in older mobility-limited community-dwelling men and women. A cross sectional study was performed in American and Swedish subjects who were examined for potential participation in a combined exercise and nutrition intervention trial. Logistic regression analysis and linear regression analyses were performed to evaluate the association for 25(OH)D with the overall score on the SBBP, chair stand, gait speed and balance. Community-dwelling (mean age 77.6 ± 5.3 years) mobility limited American (n=494) and Swedish (n=116) females (59%) and males. The SPPB (0-12 points) includes chair stand (s), gait speed (m/s) and a balance test. Mobility limitation i.e., SPPB score ≤ 9 was an inclusion criterion. A blood sample was obtained to measure serum 25(OH)vitamin D concentrations. No clear association of 25(OH)D with SPPB scores was detected either when 25(OH)D was assessed as a continuous variable or when categorized according to serum concentrations of <50, 50-75 or <75 nmol/L. However, when analyzing the relationship between 25(OH)D and seconds to perform the chair stands, a significant quadratic relationship was observed. Thus, at serum levels of 25(OH)D above 74 nmol/L, higher concentrations appeared to be advantageous for the chair stand test, whereas for serum levels below 74 nmol/L this association was not observed. This cross- sectional study lacked clear association between serum 25(OH)D and physical performance in mobility limited adults. A potentially interesting observation was that at higher serum levels of 25(OH)D a better performance on the chair stand test was indicated.

  8. "Acceptance of the Limits of Knowability in Oneself and Others": Performative Politics and Relational Ethics in the Primary School Classroom

    Science.gov (United States)

    Teague, Laura

    2015-01-01

    This paper takes up Judith Butler's calls to suspend the desire to completely know the other, and discusses these in relation to the pedagogic relationship in the classroom. It draws upon existing accounts of performative reinscription as a politics to disrupt exclusionary schooling practices and discusses these alongside Butler's theories of…

  9. Energy Efficiency and Performance Limiting Effects in Thermo-Osmotic Energy Conversion from Low-Grade Heat.

    Science.gov (United States)

    Straub, Anthony P; Elimelech, Menachem

    2017-11-07

    Low-grade heat energy from sources below 100 °C is available in massive quantities around the world, but cannot be converted to electricity effectively using existing technologies due to variability in the heat output and the small temperature difference between the source and environment. The recently developed thermo-osmotic energy conversion (TOEC) process has the potential to harvest energy from low-grade heat sources by using a temperature difference to create a pressurized liquid flux across a membrane, which can be converted to mechanical work via a turbine. In this study, we perform the first analysis of energy efficiency and the expected performance of the TOEC technology, focusing on systems utilizing hydrophobic porous vapor-gap membranes and water as a working fluid. We begin by developing a framework to analyze realistic mass and heat transport in the process, probing the impact of various membrane parameters and system operating conditions. Our analysis reveals that an optimized system can achieve heat-to-electricity energy conversion efficiencies up to 4.1% (34% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and an operating pressure of 5 MPa (50 bar). Lower energy efficiencies, however, will occur in systems operating with high power densities (>5 W/m 2 ) and with finite-sized heat exchangers. We identify that the most important membrane properties for achieving high performance are an asymmetric pore structure, high pressure resistance, a high porosity, and a thickness of 30 to 100 μm. We also quantify the benefits in performance from utilizing deaerated water streams, strong hydrodynamic mixing in the membrane module, and high heat exchanger efficiencies. Overall, our study demonstrates the promise of full-scale TOEC systems to extract energy from low-grade heat and identifies key factors for performance optimization moving forward.

  10. Understanding and removing surface states limiting charge transport in TiO2 nanowire arrays for enhanced optoelectronic device performance.

    Science.gov (United States)

    Sheng, Xia; Chen, Liping; Xu, Tao; Zhu, Kai; Feng, Xinjian

    2016-03-01

    Charge transport within electrode materials plays a key role in determining the optoelectronic device performance. Aligned single-crystal TiO 2 nanowire arrays offer an ideal electron transport path and are expected to have higher electron mobility. Unfortunately, their transport is found not to be superior to that in nanoparticle films. Here we show that the low electron transport in rutile TiO 2 nanowires is mainly caused by surface traps in relatively deep energy levels, which cannot be removed by conventional approaches, such as oxygen annealing treatment. Moreover, we demonstrate an effective wet-chemistry approach to minimize these trap states, leading to over 20-fold enhancement in electron diffusion coefficient and 62% improvement in solar cell performance. On the basis of our results, the potential of TiO 2 NWs can be developed and well-utilized, which is significantly important for their practical applications.

  11. Performance Limits and IR Design Challenges of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology

    CERN Document Server

    Brüning, Oliver Sim; Ostojic, R; Rossi, L; Ruggiero, F; Scandale, Walter; Taylor, T

    2004-01-01

    We investigate the maximum LHC performance for a standard IR design based on classical NbTi insertion magnets. We include in our analysis a ternary Nb-based ductile allow such as NbTi(Ta), a less developed but relatively cheap superconducting material which may allow to gain about 1 T in the peak field in the coils, and discuss the corresponding luminosity reach for a possible LHC upgrade compared to that based on Nb$_{3}$Sn magnets.

  12. Performance limits of coated particle fuel. Part I. The significance of empirical performance diagrams and mathematical models in fuel development and power reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Graham, L. W.; Hick, H.

    1973-06-15

    This report introduces a general survey of our present knowledge and understanding of coated particle fuel performance. It defines first the reference power reactor conditions and the reference coated particle design on which the survey is centred. It describes then the typical strategy which has been followed in coated particle fuel development by the Dragon Project R & D Branch. Finally it shows the priorities which have governed the time scale and scope of fuel development and of the present review.

  13. Motivating health workers up to a limit: partial effects of performance-based financing on working environments in Nigeria.

    Science.gov (United States)

    Bhatnagar, Aarushi; George, Asha S

    2016-09-01

    In 2012, the Nigerian government launched performance-based financing (PBF) in three districts providing financial incentives to health workers based on the quantity and quality of service provision. They were given autonomy to use funds for operational costs and performance bonuses. This study aims to understand changes in perceived motivation among health workers with the introduction of PBF in Wamba district, Nigeria. The study used a qualitative research design to compare perceptions of health workers in facilities receiving PBF payments in the pilot district of Wamba to those that were not. In-depth semi-structured interviews (n = 39) were conducted with health workers from PBF and non-PBF facilities along with managers of the PBF project. Framework analysis was used to identify patterns and variations in responses. Facility records were collated and triangulated with qualitative data. Health workers receiving PBF payments reported to be 'awakened' by performance bonuses and improved working environments including routine supportive supervision and availability of essential drugs. They recounted being more punctual, hard working and proud of providing better services to their communities. In comparison, health workers in non-PBF facilities complained about the dearth of basic equipment and lack of motivating strategies. However, health workers from both sets of facilities considered there to be a severe shortage of manpower resulting in excessive workload, fatigue and general dissatisfaction. PBF strategies can succeed in motivating health workers by bringing about a change in incentives and working conditions. However, such programmes need to be aligned with human resource reforms including timely recruitment and appropriate distribution of health workers to prevent burn out and attrition. As people working on the frontline of constrained health systems, health workers are responsive to improved incentives and working conditions, but need more

  14. Module-scale analysis of pressure retarded osmosis: performance limitations and implications for full-scale operation.

    Science.gov (United States)

    Straub, Anthony P; Lin, Shihong; Elimelech, Menachem

    2014-10-21

    We investigate the performance of pressure retarded osmosis (PRO) at the module scale, accounting for the detrimental effects of reverse salt flux, internal concentration polarization, and external concentration polarization. Our analysis offers insights on optimization of three critical operation and design parameters--applied hydraulic pressure, initial feed flow rate fraction, and membrane area--to maximize the specific energy and power density extractable in the system. For co- and counter-current flow modules, we determine that appropriate selection of the membrane area is critical to obtain a high specific energy. Furthermore, we find that the optimal operating conditions in a realistic module can be reasonably approximated using established optima for an ideal system (i.e., an applied hydraulic pressure equal to approximately half the osmotic pressure difference and an initial feed flow rate fraction that provides equal amounts of feed and draw solutions). For a system in counter-current operation with a river water (0.015 M NaCl) and seawater (0.6 M NaCl) solution pairing, the maximum specific energy obtainable using performance properties of commercially available membranes was determined to be 0.147 kWh per m(3) of total mixed solution, which is 57% of the Gibbs free energy of mixing. Operating to obtain a high specific energy, however, results in very low power densities (less than 2 W/m(2)), indicating that the trade-off between power density and specific energy is an inherent challenge to full-scale PRO systems. Finally, we quantify additional losses and energetic costs in the PRO system, which further reduce the net specific energy and indicate serious challenges in extracting net energy in PRO with river water and seawater solution pairings.

  15. An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

    Science.gov (United States)

    Gayen, P K; Chatterjee, D; Goswami, S K

    2016-05-01

    In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Pushing the limits : from better bits to faster coil, companies leverage technology to ramp up onshore drilling performance

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.

    2009-06-15

    Horizontal drilling and drilling with coiled tubing are two well drilling techniques that have steadily gained ground in the drilling industry. Most of the techniques evolved in western Canada and Alaska, but are now being successfully used south of the border. This article discussed the leveraging of technology by drilling companies in order to ramp up onshore drilling performance. Calgary-based Xtreme Coil Drilling Corp. leveraged its unique coil over top drive rigs in order to score more speed records and set new marks in both the United States Rockies and Mexico. This article also referred to other companies and their wells that have set records, including CNX Gas Corporation and the Marcellus Shale prospect; Smith International and its horizontal turbodrilling of a Pennsylvanian reservoir; and Baker Oil Tools' new rotating, self-aligning multilateral (RAM) system. For each of these examples, the article described the technology and the challenges encountered by the companies as well as the objectives of the project, and results of the drilling efforts. 2 figs.

  17. Understanding performance limitation and suppression of leakage current or self-discharge in electrochemical capacitors: a review.

    Science.gov (United States)

    Ike, Innocent S; Sigalas, Iakovos; Iyuke, Sunny

    2016-01-14

    Self-discharge is known to have considerable adverse effects on the performance and application of electrochemical capacitors (ECs). Thus, obtaining an understanding of EC self-discharge mechanism(s) and subsequent derivation and solution of EC models, subject to a particular mechanism or combination of mechanisms during charging, discharging and storage of the device, is the only way to solve problems associated with EC self-discharge. In this review, we summarize recent progress with respect to EC self-discharge by considering the two basic types, electric double-layer capacitors (EDLC) and pseudocapacitors, and their hybrids with their respective charge storage mechanisms, distinguishable self-discharge mechanisms, charge redistribution and charge/energy loss during self-discharge. It was clearly observed that most of the voltage reduction is not purely due to the self-discharge effect but is basically due to redistribution of charge carriers deep inside pores and can therefore be retrieved from a capacitor during long-time discharging. Tuning the self-discharge rate is therefore feasible for single-walled carbon nanotube (SWNT) ECs and can be achieved by simply adjusting the surface chemistry of the nanotubes. The effects of surface chemistry modification on EC self-discharge are very important in studying and suppressing the self-discharge process and will benefit potential applications of ECs with respect to energy retention. Self-discharge can be averted by the use of redox couples that are transformed to insoluble species via electrolysis and adsorbed onto the activated carbon electrode in redox-couple EDLCs, thus transforming the EDLC electrolyte into a material that can store charge. Self-discharge in ECs can also be successfully suppressed by utilizing an ion-interchange layer (ion-exchange membrane), separator or CuSO4 mobile electrolyte that can be converted into an insoluble species by electrolysis during the charge/discharge process. This will help

  18. Influence of limit-feeding and time of day of feed availability to growing calves on growth performance and feeding behavior in cold weather.

    Science.gov (United States)

    Prezotto, L D; Gilbery, T C; Bauer, M L; Islas, A; Swanson, K C

    2017-11-01

    Objective swere to determine the effects of limit-feeding and time of feed access in cold weather on growth performance and feeding behavior of growing calves fed a corn silage-based diet. Sixty-six steers (BW = 317 ± 5.3 kg) and 30 heifers (BW = 239 ± 7.6 kg) were assigned randomly to dietary treatment: 1) ad libitum feed intake (AL), 2) limit-fed to 80% of the average DMI of the AL group on a BW basis in the daytime (0601-1759 h; LF-D), 3) limit-fed to 80% of the average DMI of the AL group on a BW basis in the nighttime (1800-0559 h; LF-N), and 4) limit-fed to 80% of the average DMI of the AL group on a BW basis, split 1/2 in the daytime and 1/2 in the nighttime (LF-S). Feed intake and feeding behavior were monitored over 84 d using the Insentec feeding system. Average daily gain, DMI, and G:F were greater ( ≤ 0.002) in the AL group compared with others. Dry matter intake was not different ( = 0.17) when comparing the LF-D with the LF-N groups. Average daily gain and G:F were greater ( ≤ 0.05) when comparing the LF-N group to the LF-D group, and were not different ( ≥ 0.51) when comparing the LF-S group with the mean of the LF-D and LF-N groups. Number of visits and meals per d was greater ( ≤ 0.001) in the LF-N than the LF-D group. Feed intake per visit was not different ( = 0.55) when comparing the AL group and others, and tended to be greater ( = 0.06) in the LF-D than the LF-N group. Feed intake per meal was greater ( Feed intake per minute (eating rate) was not influenced by treatment. In conclusion, limit-feeding at 80% of ad libitum intake decreased ADG and G:F. Limit-feeding in the nighttime as compared to limit-feeding in the daytime improves growth performance and increases feeding activity (number of visits and meals per d) which could be because of increased heat production to help maintain body temperature and thus reduce maintenance energy requirements.

  19. Corrida em piscina funda: limites e possibilidades para o alto desempenho Velocidad en piscina de profundidad: límites y posibilidades para un alto desempeño Deep water running: limits and possibilities for high performance

    Directory of Open Access Journals (Sweden)

    Leonardo Alexandre Peyré-Tartaruga

    2006-10-01

    Full Text Available O objetivo deste estudo foi analisar os limites e possibilidades da utilização da corrida em piscina funda no treinamento de corredores de rendimento. Além disso, são discutidas as respostas agudas submáximas, máximas e crônicas, do ponto de vista fisiológico e biomecânico entre a corrida em terra e em piscina funda. As respostas máximas de freqüência cardíaca e consumo de oxigênio são menores no exercício aquático do que na corrida terrestre. Dados experimentais sugerem o uso do treinamento de corrida em piscina funda para corredores de rendimento; contudo, essas evidências são limitadas para treinamentos de até 10 semanas.El objetivo de este estudio ha sido el de analizar los límites y posibilidades de la utilización de carreras de velocidad en piscina de profundidad durante el entrenamiento de velocista de rendimiento. Además de esto, son discutidas las respuestas agudas submáximas, máximas y crónicas, bajo el punto de vista fisiológico y biomecánico entre la carrera en tierra y en piscina profunda. Las respuestas máximas de frecuencia cardíaca y consumo de oxígeno son menores en el ejercicio acuático que en la de tierra. Datos experimentales sugieren el uso de entrenamiento de carrera en piscina profunda para velocistas de rendimiento, sin embargo estas evidencias son limitadas a entrenamientos de hasta 10 semanas.The purpose of this study was to analyze the limits and possibilities of deep water running on training of performance runners. Besides, it has been discussed the submaximal acute, maximal acute and chronical responses, following physiological and biomechanical aspects between running on land and deep water running. Heart rate and oxygen uptake's maximal responses are lower in aquatic exercise than in running on land. Experimental evidences suggest the deep water running training for performance athletes, but these studies are limited in training program until ten weeks.

  20. Evaluation of limiting factors affecting photovoltaic performance of low-temperature-processed TiO₂ films in dye-sensitized solar cells.

    Science.gov (United States)

    Lee, Taek-Yong; Kim, Hui-Seon; Park, Nam-Gyu

    2014-04-14

    Limiting factors affecting photovoltaic performance of dye-sensitized solar cell employing low-temperature-processed TiO2 films were investigated. TiO2 films were prepared at a low temperature of 200 °C using the normal alcohol-containing binder-free TiO2 paste (LT200). Their photovoltaic performance was compared to a high-temperature (550 °C) annealed TiO2 film prepared using a polymer binder containing TiO2 paste (HT550). Compared to the proportional increase in conversion efficiency with TiO2 film thickness upto 14 μm for HT550, the increase in efficiency was terminated at relatively smaller thickness of about 8 μm for LT200 mainly due to unaugmented photocurrent. From the transient photocurrent-voltage studies, the electron transport rate was found to be almost identical, while charge recombination was one order of magnitude faster for LT200. Consequently, the electron diffusion length was more than 2-3 times shorter for LT200 than for HT550. Electron diffusion length and electron life time obtained from electrochemical impedance analysis were well consistent with those observed from transient measurement. Density of states (DOS) was evaluated to be shallow and narrow in LT200, which was responsible for limiting photovoltaic performance in the low-temperature processed TiO2 film. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Strong Relation between Muscle Mass Determined by D3-creatine Dilution, Physical Performance and Incidence of Falls and Mobility Limitations in a Prospective Cohort of Older Men.

    Science.gov (United States)

    Cawthon, Peggy M; Orwoll, Eric S; Peters, Katherine E; Ensrud, Kristine E; Cauley, Jane A; Kado, Deborah M; Stefanick, Marcia L; Shikany, James M; Strotmeyer, Elsa S; Glynn, Nancy W; Caserotti, Paolo; Shankaran, Mahalakshmi; Hellerstein, Marc; Cummings, Steven R; Evans, William J

    2018-06-12

    Direct assessment of skeletal muscle mass in older adults is clinically challenging. Relationships between lean mass and late-life outcomes have been inconsistent. The D3-creatine dilution method provides a direct assessment of muscle mass. Muscle mass was assessed by D3-creatine (D3Cr) dilution in 1,382 men (mean age, 84.2 yrs). Participants completed the Short Physical Performance Battery (SPPB); usual walking speed (6 meters); and DXA lean mass. Men self-reported mobility limitations (difficulty walking 2-3 blocks or climbing 10 steps); recurrent falls (2+); and serious injurious falls in the subsequent year. Across quartiles of D3Cr muscle mass/body mass, multivariate linear models calculated means for SPPB and gait speed; multivariate logistic models calculated odds ratios for incident mobility limitations or falls. Compared to men in the highest quartile, those in the lowest quartile of D3Cr muscle mass/body mass had slower gait speed (Q1: 1.04 vs Q4: 1.17 m/s); lower SPPB (Q1: 8.4 vs Q4: 10.4 points); greater likelihood of incident serious injurious falls (OR Q1 vs Q4: 2.49, 95% CI: 1.37, 4.54); prevalent mobility limitation (OR Q1 vs Q4,: 6.1, 95%CI: 3.7, 10.3) and incident mobility limitation (OR Q1 vs Q4: 2.15 95% CI: 1.42, 3.26); p for trend strongly related to physical performance, mobility and incident injurious falls in older me.

  2. Knock-Limited Performance of Triptane and 28-R Fuel Blends as Affected by Changes in Compression Ratio and in Engine Operating Variables

    Science.gov (United States)

    Brun, Rinaldo J.; Feder, Melvin S.; Fisher, William F.

    1947-01-01

    A knock-limited performance investigation was conducted on blends of triptane and 28-P fuel with a 12-cylinder, V-type, liquid-cooled aircraft engine of 1710-cubic-inch displacement at three compression ratios: 6.65, 7.93, and 9.68. At each compression ratio, the effect of changes in temperature of the inlet air to the auxiliary-stage supercharger and in fuel-air ratio were investigated at engine speeds of 2280 and. 3000 rpm. The results show that knock-limited engine performance, as improved by the use of triptane, allowed operation at both take-off and cruising power at a compression ratio of 9.68. At an inlet-air temperature of 60 deg F, an engine speed of 3000 rpm ; and a fuel-air ratio of 0,095 (approximately take-off conditions), a knock-limited engine output of 1500 brake horsepower was possible with 100-percent 28-R fuel at a compression ratio of 6.65; 20-percent triptane was required for the same power output at a compression ratio of 7.93, and 75 percent at a compression ratio of 9.68 allowed an output of 1480 brake horsepower. Knock-limited power output was more sensitive to changes in fuel-air ratio as the engine speed was increased from 2280 to 3000 rpm, as the compression ratio is raised from 6.65 to 9.68, or as the inlet-air temperature is raised from 0 deg to 120 deg F.

  3. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Song, Hongjian; Olsen, Ole H; Persson, Egon

    2014-01-01

    Factor VIIa (FVIIa) is a trypsin-like protease which plays an important role in initiating blood coagulation. Very limited structural information is available for the free, inactive form of FVIIa that circulates in the blood prior to vascular injury and the molecular details of its activity...... signal extends to the EGF1 domain in the light chain of FVIIa, underscoring a remarkable intra- and interdomain allosteric regulation of this trypsin-like protease....

  4. Proposed limiting values for performance criteria in acceptance testing of diagnostic X-ray equipment in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Baeuml, A.

    1989-01-01

    In the Federal Republic of Germany a new X-ray ordinance came into force in 1988 containing a specific paragraph on quality assurance for all medical X-ray units stipulating acceptance tests, regular checks and supervision by medical bodies and the competent authorities. Acceptance testing is to be performed by engineers from equipment suppliers of manufacturers in new and existing installations. It is expected that the service engineers will adjust the equipment in such a way as to obtain optimal performance before measurements are made, the results of which are to be stated in a certificate describing quality status of the equipment. A working group has developed guidelines for these acceptance tests. Items to be measured are reported and proposed limiting values and their tolerances are discussed. (author)

  5. Proposed limiting values for performance criteria in acceptance testing of diagnostic X-ray equipment in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Baeuml, A.

    1989-01-01

    In the Federal Republic of Germany a new X-ray ordinance came into force in 1988 containing a specific paragraph on quality assurance for all medical X-ray units stipulating acceptance tests, regular checks and supervision by medical bodies and the competent authorities. Acceptance testing is to be performed by engineers from the equipment suppliers or manufacturers in new and also existing installations. It is expected that the service engineers will adjust the equipment in such a way as to obtain optimal performance before measurements are made, the results of which are to be stated in a certificate describing the quality status of the equipment. A working group has developed guidelines for these acceptance tests. The items to be measured are reported and the proposed limiting values and their tolerances are discussed. (author)

  6. Providers with Limited Experience Perform Better in Advanced Life Support with Assistance Using an Interactive Device with an Automated External Defibrillator Linked to a Ventilator.

    Science.gov (United States)

    Busch, Christian Werner; Qalanawi, Mohammed; Kersten, Jan Felix; Kalwa, Tobias Johannes; Scotti, Norman Alexander; Reip, Wikhart; Doehn, Christoph; Maisch, Stefan; Nitzschke, Rainer

    2015-10-01

    Medical teams with limited experience in performing advanced life support (ALS) or with a low frequency of cardiopulmonary resuscitation (CPR) while on duty, often have difficulty complying with CPR guidelines. This study evaluated whether the quality of CPR of trained medical students, who served as an example of teams with limited experience in ALS, could be improved with device assistance. The primary outcome was the hands-off time (i.e., the percentage of the entire CPR time without chest compressions). The secondary outcome was seven time intervals, which should be as short as possible, and the quality of ventilations and chest compressions on the mannequin. We compared standard CPR equipment to an interactive device with visual and acoustic instructions for ALS workflow measures to guide briefly trained medical students through the ALS algorithm in a full-scale mannequin simulation study with a randomized crossover study design. The study equipment consisted of an automatic external defibrillator and ventilator that were electronically linked and communicating as a single system. Included were regular medical students in the third to sixth years of medical school of one class who provided written informed consent for voluntary participation and for the analysis of their CPR performance data. No exclusion criteria were applied. For statistical measures of evaluation we used an analysis of variance for crossover trials accounting for treatment effect, sequence effect, and carry-over effect, with adjustment for prior practical experience of the participants. Forty-two medical students participated in 21 CPR sessions, each using the standard and study equipment. Regarding the primary end point, the study equipment reduced the hands-off time from 40.1% (95% confidence interval [CI] 36.9-43.4%) to 35.6% (95% CI 32.4-38.9%, p = 0.031) compared with the standard equipment. Within the prespecified secondary end points, study equipment reduced the time interval until

  7. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry.

    Science.gov (United States)

    Song, Hongjian; Olsen, Ole H; Persson, Egon; Rand, Kasper D

    2014-12-19

    Factor VIIa (FVIIa) is a trypsin-like protease that plays an important role in initiating blood coagulation. Very limited structural information is available for the free, inactive form of FVIIa that circulates in the blood prior to vascular injury and the molecular details of its activity enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form, as induced either by its cofactor tissue factor or a covalent active site inhibitor. Identified regulatory residues are situated at key sites across one continuous surface of the protease domain spanning the TF-binding helix across the activation pocket to the calcium binding site and are embedded in elements of secondary structure and at the base of flexible loops. Thus these residues are optimally positioned to mediate crosstalk between functional sites in FVIIa, particularly the cofactor binding site and the active site. Our results unambiguously show that the conformational allosteric activation signal extends to the EGF1 domain in the light chain of FVIIa, underscoring a remarkable intra- and interdomain allosteric regulation of this trypsin-like protease. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Performance

    Directory of Open Access Journals (Sweden)

    M. Rabie

    2016-04-01

    The design of hybrid MSE/SN walls is complicated as it is a composite of two different reinforcement techniques, traditional limit equilibrium approaches cannot be used alone for design of such walls, it shall be supported by numerical methods for estimation of the global factor of safety and failure surface. The limit equilibrium approaches can be used for the estimation of internal stability and facing connection for both soil nails and mechanically stabilized walls.

  9. ‘The engine just started coughing!’ — Limits of physical performance, aging and career continuity in elite endurance sports

    DEFF Research Database (Denmark)

    Ronkainen, Noora; Ryba, Tatiana; Nesti, Mark

    2013-01-01

    This research examines male endurance athletes' experience of aging and/or reaching the perceived limits of physical performance. More specifically, the current study aimed to explore how existential meanings attached to these experiences are connected with athletes' decision-making concerning...... career continuity and retirement. Life story interviews were conducted with 10 Finnish runners and/or orienteers aged between 25 and 62 and the data was analyzed with an existential-narrative framework. Four major storylines related to aging were identified: The end of an era, putting things...... the normativity of retirement when unable to improve their results anymore, other athletes demonstrated career continuity and positive aspects in the late career years, such as lack of competitive anxiety, finding perspective and increased enjoyment in running. We suggest that through awareness of alternative...

  10. Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, Bojan [Georgia Inst. of Technology, Atlanta, GA (United States); Maldonado, Ivan [Univ. of Tennessee, Knoxville, TN (United States)

    2016-04-14

    The research performed in this project addressed the issue of low heavy metal loading and the resulting reduced cycle length with increased refueling frequency, inherent to all FHR designs with solid, non-movable fuel based on TRISO particles. Studies performed here focused on AHTR type of reactor design with plate (“plank”) fuel. Proposal to FY12 NEUP entitled “Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors” was selected for award, and the 3-year project started in August 2012. A 4-month NCE was granted and the project completed on December 31, 2015. The project was performed by Georgia Tech (Prof. Bojan Petrovic, PI) and University of Tennessee (Prof. Ivan Maldonado, Co-PI), with a total funding of $758,000 over 3 years. In addition to two Co-PIs, the project directly engaged 6 graduate students (at doctoral or MS level) and 2 postdoctoral researchers. Additionally, through senior design projects and graduate advanced design projects, another 23 undergraduate and 12 graduate students were exposed to and trained in the salt reactor technology. We see this as one of the important indicators of the project’s success and effectiveness. In the process, 1 journal article was published (with 3 journal articles in preparation), together with 8 peer-reviewed full conference papers, 8 peer-reviewed extended abstracts, as well as 1 doctoral dissertation and 2 master theses. The work included both development of models and methodologies needed to adequately analyze this type of reactor, fuel, and its fuel cycle, as well as extensive analyses and optimization of the fuel and core design.

  11. Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors

    International Nuclear Information System (INIS)

    Petrovic, Bojan; Maldonado, Ivan

    2016-01-01

    The research performed in this project addressed the issue of low heavy metal loading and the resulting reduced cycle length with increased refueling frequency, inherent to all FHR designs with solid, non-movable fuel based on TRISO particles. Studies performed here focused on AHTR type of reactor design with plate ('plank') fuel. Proposal to FY12 NEUP entitled 'Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors' was selected for award, and the 3-year project started in August 2012. A 4-month NCE was granted and the project completed on December 31, 2015. The project was performed by Georgia Tech (Prof. Bojan Petrovic, PI) and University of Tennessee (Prof. Ivan Maldonado, Co-PI), with a total funding of $758,000 over 3 years. In addition to two Co-PIs, the project directly engaged 6 graduate students (at doctoral or MS level) and 2 postdoctoral researchers. Additionally, through senior design projects and graduate advanced design projects, another 23 undergraduate and 12 graduate students were exposed to and trained in the salt reactor technology. We see this as one of the important indicators of the project's success and effectiveness. In the process, 1 journal article was published (with 3 journal articles in preparation), together with 8 peer-reviewed full conference papers, 8 peer-reviewed extended abstracts, as well as 1 doctoral dissertation and 2 master theses. The work included both development of models and methodologies needed to adequately analyze this type of reactor, fuel, and its fuel cycle, as well as extensive analyses and optimization of the fuel and core design.

  12. Performance limitations in thieno[3,4-c]pyrrole-4,6-dione-based polymer:ITIC solar cells

    KAUST Repository

    Yang, Fan

    2017-08-15

    We report a systematic study of the efficiency limitations of non-fullerene organic solar cells that exhibit a small energy loss (Eloss) between the polymer donor and the non-fullerene acceptor. To clarify the impact of Eloss on the performance of the solar cells, three thieno[3,4-c]pyrrole-4,6-dione-based conjugated polymers (PTPD3T, PTPD2T, and PTPDBDT) are employed as the electron donor, which all have complementary absorption spectra compared with the ITIC acceptor. The corresponding photovoltaic devices show that low Eloss (0.54 eV) in PTPDBDT:ITIC leads to a high open-circuit voltage (Voc) of 1.05 V, but also to a small quantum efficiency, and in turn photocurrent. The high Voc or small energy loss in the PTPDBDT-based solar cells is a consequence of less non-radiative recombination, whereas the low quantum efficiency is attributed to the unfavorable micro-phase separation, as confirmed by the steady-state and time-resolved photoluminescence experiments, grazing-incidence wide-angle X-ray scattering, and resonant soft X-ray scattering (R-SoXS) measurements. We conclude that to achieve high performance non-fullerene solar cells, it is essential to realize a large Voc with small Eloss while simultaneously maintaining a high quantum efficiency by manipulating the molecular interaction in the bulk-heterojunction.

  13. Ensenanzas en un gimnasio: an investigation of modeling and verbal rehearsal on the motor performance of Hispanic limited English proficient children.

    Science.gov (United States)

    Meaney, K S; Edwards, R

    1996-03-01

    This study investigated the effects of modeling and verbal rehearsal on the motor performance of English-speaking and limited English proficient (LEP) children. Children (N = 64) in 4th-grade classes were randomly assigned to conditions in a 2 x 2 x 2 x 2 (Gender x Primary Language x Model Type x Rehearsal) factorial design. Boys and girls whose primary language was English or Spanish were assigned to either a verbal model or no-model condition as well as to a verbal rehearsal or no-rehearsal condition of the motor skills required to be performed. Analysis of variance revealed a significant Model Type x Primary Language interaction as well as a significant Rehearsal x Primary Language interaction. Follow-up analyses revealed that English-speaking children provided with a verbal rehearsal strategy recalled significantly more skills than English-speaking children in the no-rehearsal condition; for LEP children, there were no differences due to rehearsal. Moreover, LEP children presented with a verbal model recalled significantly more skills than LEP children in the no-model condition; for English-speaking children, there were no differences attributed to model type. These results indicate that effective modeling conditions that are provided with verbal cues in English are related to children's primary language.

  14. Performance limitations in thieno[3,4-c]pyrrole-4,6-dione-based polymer:ITIC solar cells

    KAUST Repository

    Yang, Fan; Qian, Deping; Balawi, Ahmed Hesham; Wu, Yang; Ma, Wei; Laquai, Fré dé ric; Tang, Zheng; Zhang, Fengling; Li, Weiwei

    2017-01-01

    We report a systematic study of the efficiency limitations of non-fullerene organic solar cells that exhibit a small energy loss (Eloss) between the polymer donor and the non-fullerene acceptor. To clarify the impact of Eloss on the performance of the solar cells, three thieno[3,4-c]pyrrole-4,6-dione-based conjugated polymers (PTPD3T, PTPD2T, and PTPDBDT) are employed as the electron donor, which all have complementary absorption spectra compared with the ITIC acceptor. The corresponding photovoltaic devices show that low Eloss (0.54 eV) in PTPDBDT:ITIC leads to a high open-circuit voltage (Voc) of 1.05 V, but also to a small quantum efficiency, and in turn photocurrent. The high Voc or small energy loss in the PTPDBDT-based solar cells is a consequence of less non-radiative recombination, whereas the low quantum efficiency is attributed to the unfavorable micro-phase separation, as confirmed by the steady-state and time-resolved photoluminescence experiments, grazing-incidence wide-angle X-ray scattering, and resonant soft X-ray scattering (R-SoXS) measurements. We conclude that to achieve high performance non-fullerene solar cells, it is essential to realize a large Voc with small Eloss while simultaneously maintaining a high quantum efficiency by manipulating the molecular interaction in the bulk-heterojunction.

  15. Growth performance, rumen fermentation, nutrient utilization, and metabolic profile of dairy heifers limit-fed distillers dried grains with ad libitum forage.

    Science.gov (United States)

    Manthey, A K; Anderson, J L

    2018-01-01

    The objective of this study was to determine the effects of feeding a corn- and soybean-product-based concentrate mix or distillers dried grains with solubles concentrate mix with ad libitum grass hay to dairy heifers. A 16-wk randomized complete block design study was conducted using 24 heifers [18 Holstein and 6 Brown Swiss; 219 ± 2 d of age (±standard deviation); 230 ± 4 kg of body weight] to evaluate the effect of diet on dry matter intake (DMI), growth performance, rumen fermentation, metabolic profile, and nutrient digestibility. Treatments were (1) corn and soybean product concentrate mix, and (2) distillers-dried-grains-with-solubles-based concentrate mix (DDG). Both concentrate mixes were limit-fed at 0.8% of body weight and grass hay was offered ad libitum. Heifers were individually fed using Calan gates and orts were recorded daily at feeding. Heifers were weighed every 2 wk and ration concentrate mix offered was adjusted accordingly. Frame measurements and body condition score were recorded every 2 wk. Rumen fluid was collected via esophageal tubing during wk 12 and 16 for pH, ammonia N, and volatile fatty acid analysis. Jugular blood samples were collected every 4 wk for metabolite and metabolic hormone analysis. Total-tract digestibility of nutrients was evaluated during wk 16 by fecal grab sampling. No treatment by week interactions were observed for any of the growth measurements and growth measurements and DMI did not differ between treatments. A treatment by time interaction was observed for rumen butyrate percentage with heifers fed DDG having a greater percentage. Total volatile fatty acid concentration, acetate molar percentage, and acetate:propionate decreased with the DDG treatment, whereas propionate molar percentage increased. No treatment by week interactions were observed for any of the metabolites or metabolic hormones measured. A tendency was observed for glucose and plasma urea nitrogen concentration to decrease with DDG. Plasma

  16. A framework for streamflow prediction in the world's most severely data-limited regions: Test of applicability and performance in a poorly-gauged region of China

    Science.gov (United States)

    Alipour, M. H.; Kibler, Kelly M.

    2018-02-01

    A framework methodology is proposed for streamflow prediction in poorly-gauged rivers located within large-scale regions of sparse hydrometeorologic observation. A multi-criteria model evaluation is developed to select models that balance runoff efficiency with selection of accurate parameter values. Sparse observed data are supplemented by uncertain or low-resolution information, incorporated as 'soft' data, to estimate parameter values a priori. Model performance is tested in two catchments within a data-poor region of southwestern China, and results are compared to models selected using alternative calibration methods. While all models perform consistently with respect to runoff efficiency (NSE range of 0.67-0.78), models selected using the proposed multi-objective method may incorporate more representative parameter values than those selected by traditional calibration. Notably, parameter values estimated by the proposed method resonate with direct estimates of catchment subsurface storage capacity (parameter residuals of 20 and 61 mm for maximum soil moisture capacity (Cmax), and 0.91 and 0.48 for soil moisture distribution shape factor (B); where a parameter residual is equal to the centroid of a soft parameter value minus the calibrated parameter value). A model more traditionally calibrated to observed data only (single-objective model) estimates a much lower soil moisture capacity (residuals of Cmax = 475 and 518 mm and B = 1.24 and 0.7). A constrained single-objective model also underestimates maximum soil moisture capacity relative to a priori estimates (residuals of Cmax = 246 and 289 mm). The proposed method may allow managers to more confidently transfer calibrated models to ungauged catchments for streamflow predictions, even in the world's most data-limited regions.

  17. Discovery of Allostery in PKA Signaling.

    Science.gov (United States)

    Zhang, Ping; Kornev, Alexandr P; Wu, Jian; Taylor, Susan S

    2015-06-01

    cAMP-dependent protein kinase (PKA) was the second protein kinase to be discovered and the PKA catalytic (C) subunit serves as a prototype for the large protein kinase superfamily that contains over 500 gene products. The protein kinases regulate much of biology in eukaryotic cells and they are now also a major therapeutic target. Although PKA was discovered nearly 50 years ago and the subsequent discovery of the regulatory subunits that bind cAMP and release the catalytic activity from the holoenzyme followed quickly. Thus in PKA we see the convergence of two major signaling mechanisms - protein phosphorylation and second messenger signaling through cAMP. Crystallography provides a foundation for understanding function, and the structure of the isolated regulatory (R) and C-subunits have been extremely informative. Yet it is the R 2 C 2 holoenzyme that predominates in cells, and one can only appreciate the allosteric features of PKA signaling by seeing the full length protein. The symmetry and the quaternary constraints that one R:C hetero-dimer exerts on the other in the holoenzyme simply are not present in the isolated subunits or even in the R:C hetero-dimer.

  18. Cell Signalling Through Covalent Modification and Allostery

    Science.gov (United States)

    Johnson, Louise N.

    Phosphorylation plays essential roles in nearly every aspect of cell life. Protein kinases catalyze the transfer of the γ-phosphate of ATP to a serine, threonine or tyrosine residue in protein substrates. This covalent modification allows activation or inhibition of enzyme activity, creates recognition sites for other proteins and promotes order/disorder or disorder/order transitions. These properties regulate ­signalling pathways and cellular processes that mediate metabolism, transcription, cell cycle progression, differentiation, cytoskeleton arrangement and cell movement, apoptosis, intercellular communication, and neuronal and immunological functions. In this lecture I shall review the structural consequences of protein phosphorylation using our work on glycogen phosphorylase and the cell cycle cyclin dependent protein kinases as illustrations. Regulation of protein phosphorylation may be disrupted in the diseased state and protein kinases have become high profile targets for drug development. To date there are 11 compounds that have been approved for clinical use in the treatment of cancer.

  19. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  20. On the effects of assembly compression on the performance of liquid-feed DMFCs under methanol-limiting conditions: A 2D numerical study

    Science.gov (United States)

    García-Salaberri, P. A.; Vera, M.

    2015-07-01

    The influence of assembly compression on the performance of liquid-feed DMFCs under methanol-limiting conditions is explored by means of a 2D/1D multiphysics across-the-channel model. The numerical formulation incorporates a comprehensive 2D description of the anode GDL, including two-phase phenomena, non-uniform anisotropic transport properties, and electrical contact resistances at the GDL/BPP interface. GDL effective properties are evaluated using empirical data corresponding to Toray® carbon paper. A simplified but physically sound 1D description, locally coupled to the 2D anode GDL model, is adopted to describe transport processes in the MPLs, membrane and cathode GDL, whereas the catalyst layers are treated as infinitely thin surfaces. Good agreement is found between the numerical results and previous experimental data. The interplay between assembly compression, bipolar plate material, and channel configuration is also investigated. The results show that there is an optimum GDL compression ratio in terms of overall power density, the optimal compression level being strongly dependent on bipolar plate material. Beyond the optimum, the detrimental effect of compression is larger in non-parallel flow fields due to the additional reduction of methanol transported by under-rib convection. The results suggest that, under certain conditions, this transport mechanism could be more important than diffusion in the anode of liquid-feed DMFCs.

  1. Performance and microbial community analysis of bio-electrocoagulation on simultaneous nitrification and denitrification in submerged membrane bioreactor at limited dissolved oxygen.

    Science.gov (United States)

    Li, Liang; Dong, Yihua; Qian, Guangsheng; Hu, Xiaomin; Ye, Linlin

    2018-06-01

    A pair of Fe-C electrodes was installed in a traditional submerged membrane bioreactor (MBR, Rc), and a novel asynchronous periodic reversal bio-electrocoagulation system (Re) was developed. The simultaneous nitrification and denitrification (SND) performance was discussed under limited dissolved oxygen (DO). Results showed that electrocoagulation enhanced total nitrogen (TN) removal from 59.48% to 75.09% at 1.2 mg/L DO. Additionally, Fe electrode could increase sludge concentration, particle size, and enzyme activities related to nitrogen removal. The enzyme activities of Hydroxylamine oxidoreductase (HAO), Nitrate Reductase (NAR), nitric oxide reductase NOR and nitrous oxide reductase (N 2 OR) in Re were 38.35%, 21.59%, 89.96% and 38.64% higher than Rc, respectively. Moreover, electrocoagulation was advantageous for nitrite accumulation, indicating partial nitrification and denitrification were more easily achieved in Re. Besides, results from high throughput sequencing analysis revealed that electrocoagulation increased the relative abundance of most genera related to nitrogen removal, including Nitrosomonas, Comamonadaceae_unclassified, Haliangium and Denitratisoma. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Benefits and Limitations of Lab-on-a-Chip Method over Reversed-Phase High-Performance Liquid Chromatography Method in Gluten Proteins Evaluation

    Directory of Open Access Journals (Sweden)

    Dragan Živančev

    2015-01-01

    Full Text Available RP-HPLC (reversed-phase high-performance liquid chromatography is widely used to determine the amounts of the different gluten protein types. However, this method is time-consuming, especially at early stages of wheat breeding, when large number of samples needs to be analyzed. On the other hand, LoaC (Lab-on-a-Chip technique has the potential for a fast, reliable, and automatable analysis of proteins. In the present study, benefits and limitations of Lab-on-a-Chip method over RP-HPLC method in gluten proteins evaluation were explored in order to determine in which way LoaC method should be improved in order to make its results more compliant with the results of RP-HPLC method. Strong correlation (P≤0.001 was found between numbers of HMW glutenin peaks determined by LoaC and RP-HPLC methods. Significant correlations (P≤0.05 were obtained between percentages of HMW and LMW glutenin subunits calculated with regard to total HMW + LMW area. Even more significant correlation (P≤0.001 was found when percentages of individual HMW areas were calculated with regard to total HMW. RP-HPLC method showed superiority in determination of gliadins since larger number and better resolution of gliadin peaks were obtained by this method.

  3. Evaluation of the performance and limitations of empirical partition-relations and process based multisurface models to predict trace element solubility in soils

    Energy Technology Data Exchange (ETDEWEB)

    Groenenberg, J.E.; Bonten, L.T.C. [Alterra, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands); Dijkstra, J.J. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands); De Vries, W. [Department of Environmental Systems Analysis, Wageningen University, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands); Comans, R.N.J. [Department of Soil Quality, Wageningen University, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands)

    2012-07-15

    Here we evaluate the performance and limitations of two frequently used model-types to predict trace element solubility in soils: regression based 'partition-relations' and thermodynamically based 'multisurface models', for a large set of elements. For this purpose partition-relations were derived for As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, V, Zn. The multi-surface model included aqueous speciation, mineral equilibria, sorption to organic matter, Fe/Al-(hydr)oxides and clay. Both approaches were evaluated by their application to independent data for a wide variety of conditions. We conclude that Freundlich-based partition-relations are robust predictors for most cations and can be used for independent soils, but within the environmental conditions of the data used for their derivation. The multisurface model is shown to be able to successfully predict solution concentrations over a wide range of conditions. Predicted trends for oxy-anions agree well for both approaches but with larger (random) deviations than for cations.

  4. Effect of Phytase Superdoses and Citric Acid on Growth Performance, Plasma Phosphorus and Tibia Ash in Broilers Fed Canola Meal-Based Diets Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    Taheri HR

    2015-06-01

    Full Text Available This experiment was conducted to investigate the effect of phytase superdoses alone or in combination with citric acid (CA in canola meal-based diets severely limited in available phosphorus (Pa on growth performance, plasma phosphorus (P, and tibia ash (TA in broilers from 22 to 42 d of age. Two hundreds and eighty 21-d-old male broilers were used in 28 pens of 10 birds per each. The experimental diets consisted of a positive control (PC diet and six negative control (NC diets which consisted of two levels of CA (0 and 20 g/Kg and three levels of phytase (0, 1000 and 4000 U/Kg in a 2 × 3 factorial arrangement. The PC diet contained 4.3 g/Kg Pa, but all NC diets contained 1.5 g/Kg Pa. Results indicated that the birds fed the PC diet had a significantly higher average daily gain (ADG, plasma P and TA, but a lower feed conversion ratio (FCR than those fed the NC diet. The ADG, FCR and plasma P values in birds fed NC diets supplemented with 4000 U/Kg phytase enzyme (with or without CA significantly reached those of birds fed the PC diet. But, addition of phytase enzyme at 1000 U/Kg only plus CA to the NC diet could significantly improve FCR and plasma P. A significant interaction was observed between phytase and CA for FCR and plasma P. Although TA values in NC + 1000 U/Kg phytase treatments (with or without CA were similar to the PC treatment, TA values of NC + 4000 U/Kg phytase treatments (with or without CA was greater than that of the PC treatment. Results of this study showed that, in severely limited Pa corn-canola meal-based diets, supplementing 4000 U/Kg phytase or also 1000 U/Kg phytase plus CA will be sufficient to obtain the comparable feed efficiency in broilers to those fed the adequate Pa diet.

  5. Quench limits

    International Nuclear Information System (INIS)

    Sapinski, M.

    2012-01-01

    With thirteen beam induced quenches and numerous Machine Development tests, the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these results is taken. The available methods of computation of the quench levels are presented together with dedicated particle shower simulations which are necessary to understand the tests. The future experiments, needed to reach better understanding of quench limits as well as limits for the machine operation are investigated. The possible strategies to set BLM (Beam Loss Monitor) thresholds are discussed. (author)

  6. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  7. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deatherage Kaiser, Brooke L [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-31

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in. × 2 in.) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent report.

  8. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kaiser, Brooke L. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-16

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results are discussed in a separate report.

  9. Effect of nitrite, limited reactive settler and plant design configuration on the predicted performance of simultaneous C/N/P removal WWTPs

    DEFF Research Database (Denmark)

    Guerrero, Javier; Flores-Alsina, Xavier; Guisasola, Albert

    2013-01-01

    as the reference model (A1). The second case (A2) adds nitrite as a new state variable, describing nitrification and denitrification as two-step processes. The third set of models (A3 and A4) considers different reactive settlers types (diffusion-limited/non limited). This study analyses the importance...

  10. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  11. Effect of high-dose phytase and citric acid, alone or in combination, on growth performance of broilers given diets severely limited in available phosphorus.

    Science.gov (United States)

    Taheri, H R; Jabbari, Z; Adibnia, S; Shahir, M H; Hosseini, S A

    2015-01-01

    1. Two trials were conducted to evaluate the effect of high-dose phytase alone or in combination with citric acid (CA) in the diet severely limited in available phosphorus (P) on performance, plasma P and plasma Ca of broilers from 22 to 42 d of age. 2. In Trial 1, 297 21-d-old female chicks were placed into 27 pens and allocated to 9 maize-soybean meal-based dietary treatments, which were a positive control [PC, 4.23 g/kg non-phytate P (NPP)] and 8 negative control (NC, 1.35 g/kg NPP) groups consisting of two concentrations of CA (0 and 20 g/kg) and 4 concentrations of phytase (0, 1000, 2000 and 4000 U/kg) in a 2 × 4 factorial arrangement. In Trial 2, 192 21-d-old male chicks were placed into 24 pens and allocated to 6 wheat-canola meal-based dietary treatments, which were a PC (4.2 g/kg NPP), a NC (1.68 g/kg NPP) and 4 NC groups consisting of two concentrations of CA (0 and 20 g/kg) and two concentrations of phytase (2000 and 4000 U/kg) in a 2 × 2 factorial arrangement. 3. In both trials, birds fed on the PC had significantly higher average daily gain (ADG), average daily feed intake (ADFI), plasma P and lower feed conversion ratio (FCR) and plasma Ca than those of birds fed on the NC. CA supplementation significantly increased ADG and ADFI. There was a significant interaction between CA and phytase on plasma P where CA improved the effect of phytase on plasma P. In Trial 1, phytase addition improved ADG, ADFI, FCR and plasma Ca linearly. 4. Briefly, this research showed the interaction effect between CA and phytase on plasma P when broilers were fed on diets based on maize-soybean meal or wheat-canola meal. The results showed that CA supplementation lowered the concentration of phytase that is needed in low NPP diets to increase plasma P.

  12. PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M Cilli

    2014-10-01

    Full Text Available This study aimed to investigate the kinematic and kinetic changes when resistance is applied in horizontal and vertical directions, produced by using different percentages of body weight, caused by jumping movements during a dynamic warm-up. The group of subjects consisted of 35 voluntary male athletes (19 basketball and 16 volleyball players; age: 23.4 ± 1.4 years, training experience: 9.6 ± 2.7 years; height: 177.2 ± 5.7 cm, body weight: 69.9 ± 6.9 kg studying Physical Education, who had a jump training background and who were training for 2 hours, on 4 days in a week. A dynamic warm-up protocol containing seven specific resistance movements with specific resistance corresponding to different percentages of body weight (2%, 4%, 6%, 8%, 10% was applied randomly on non consecutive days. Effects of different warm-up protocols were assessed by pre-/post- exercise changes in jump height in the countermovement jump (CMJ and the squat jump (SJ measured using a force platform and changes in hip and knee joint angles at the end of the eccentric phase measured using a video camera. A significant increase in jump height was observed in the dynamic resistance warm-up conducted with different percentages of body weight (p 0.05. In jump movements before and after the warm-up, while no significant difference between the vertical ground reaction forces applied by athletes was observed (p>0.05, in some cases of resistance, a significant reduction was observed in hip and knee joint angles (p<0.05. The dynamic resistance warm-up method was found to cause changes in the kinematics of jumping movements, as well as an increase in jump height values. As a result, dynamic warm-up exercises could be applicable in cases of resistance corresponding to 6-10% of body weight applied in horizontal and vertical directions in order to increase the jump performance acutely.

  13. The Use of Limiting Currents in Determination of the Effect of Viscosity in Electrochemical Experiments Performed in Mixtures of Water with Some Organic Co-Solvents

    Czech Academy of Sciences Publication Activity Database

    Zuman, P.; Rozbroj, Dan; Ludvík, Jiří; Aleksić, M.; Camaione, L.; Celik, H.

    2003-01-01

    Roč. 553, - (2003), s. 135-138 ISSN 0022-0728 R&D Projects: GA ČR GA203/02/0983 Institutional research plan: CEZ:AV0Z4040901 Keywords : limiting currents * viscosity * polarography Subject RIV: CG - Electrochemistry Impact factor: 2.076, year: 2003

  14. THE IMPACT OF GOVERNMENT POLICY IMPLEMENTATION ON THE LIMITATION OF IMPORT CATTLE TO COMPANY’S STRATEGY IN THE FRAMEWORK OF MAINTAINING COMPANY PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Marhendra A.V.H.

    2017-11-01

    Full Text Available This research aims to determine the company's strategy in order to maintain the company's performance as a result of import cattle quota restriction. The policy of import cattle restriction imposed by the Indonesian government certainly has a significant impact on cattle importing companies, especially PT Karunia Alam Sentosa Abadi (KASA, Lampung - Indonesia. PT Karunia Alam Sentosa Abadi (KASA enforces various-new business strategies to maintain the company performance from quota import policy. The results of the study show that there are several strategies applied by the company such as Volume to Performance Strategy, Average Daily Gain (ADG improvement, Marketing Network Evaluation, Leasing Company Facilities, and Daily Workforce Reduction.

  15. Performance limits of coated particle fuel. Part II. Mechanical failure of coated particles due to internal gas pressure and kernel swelling

    Energy Technology Data Exchange (ETDEWEB)

    Hick, H.; Nabielek, H.; Harrison, T. A.

    1973-10-15

    This report presents a summary of experimental results and their theoretical explanation with regard to the "Pressure Failure" of coated particle fuel. While the experimental results refer mainly to the Dragon Reference Particle as proposed for typical Low Enriched Homogeneous Prismatic Steam Cycle HTR Power Reactors, the theoretical understanding of the phenomena and the mathematical models for their description are not limited to a specific design line.

  16. How lowering speed limits in an urban highway affects traffics performance and emissions: the case of Madrid M-30 ring-road

    OpenAIRE

    Pérez Prada, Fiamma; Monzón de Cáceres, Andrés

    2014-01-01

    The city of Madrid keeps not meeting the GHG and air pollutant limits set by the European legislation. A broad range of strategies have being taken into account to reduce both types of emissions; however traffic management meas ures are usually consigned to the sidelines. In 2004, Madrid City Council launched a plan to re-design its inner ring-road supported by a socioeconomic study that evaluated the environmental and operational benefits of the project. For safety reasons the planned spe...

  17. Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions† †Electronic supplementary information (ESI) available: Characterization data and additional tables and figures. CCDC 1515722 and 1515723. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc04070a

    Science.gov (United States)

    Yang, Linlin; Jing, Xu; An, Bowen; Yang, Yang

    2017-01-01

    By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system. PMID:29675152

  18. Impact of the limitations of state-of-the-art micro-fabrication processes on the performance of pillar array columns for liquid chromatography.

    Science.gov (United States)

    Op de Beeck, Jeff; De Malsche, Wim; Tezcan, Deniz S; De Moor, Piet; Desmet, Gert

    2012-05-25

    We report on the practical limitations of the current state-of-the-art in micro-fabrication technology to produce the small pillar sizes that are needed to obtain high efficiency pillar array columns. For this purpose, nine channels with a different pillar diameter, ranging from 5 to 0.5 μm were fabricated using state-of the-art deep-UV lithography and deep reactive ion etching (DRIE) etching technology. The obtained results strongly deviated from the theoretically expected trend, wherein the minimal plate height (H(min)) would reduce linearly with the pillar diameter. The minimal plate height decreases from 1.7 to 1.2 μm when going from 4.80 to 3.81 μm diameter pillars, but as the dimensions are further reduced, the minimal plate heights rise again to values around 2 μm. The smallest pillar diameter even produced the worst minimal plate height (4 μm). An in-depth scanning electron microscopy (SEM) inspection of the different channels clearly reveals that these findings can be attributed to the micro-fabrication limitations that are inevitably encountered when exploring the limits of deep-UV lithography and DRIE etching processes. When the target dimensions of the design approach the etching resolution limits, the band broadening increases in a strongly non-linear way with the decreased pillar dimensions. This highly non-linear relationship can be understood from first principles: when the machining error is of the order of 100-200 nm and when the target design size for the inter-pillar distance is of the order of 250 nm, this inevitably leads to pores that will range in size between 50 and 450 nm that we want to highlight with our paper highly non-linear relationship. This highly non-linear relationship can be understood from first principles: when the machining error is of the order of 100-200 nm and when the target design size for the inter-pillar distance is of the order of 250 nm, this inevitably leads to pores that will range in size between 50 and 450

  19. Limitations of experiments performed in artificially made OECD standard soils for predicting cadmium, lead and zinc toxicity towards organisms living in natural soils

    DEFF Research Database (Denmark)

    Sydow, Mateusz; Chrzanowski, Lukasz; Cedergreen, Nina

    2017-01-01

    . ERMs performed better than FIAMs. Pearson's r for log10-transformed total metal based EC50s values (ERM) ranged from 0.25 to 0.74, suggesting a general correlation between predicted and measured values. Yet, root-mean-square-error (RMSE) ranged from 0.16 to 0.87 and was either smaller or comparable...

  20. Growth performance and total tract nutrient digestion for Holstein heifers limit-fed diets high in distillers grains with different forage particle sizes

    Science.gov (United States)

    This study evaluated dairy heifer growth performance and total tract nutrient digestion when fed diets high in dried distillers grains with solubles (DDGS) with different forage particle size. An 8-wk randomized complete block design study was conducted utilizing twenty-two Holstein heifers (123 ±...

  1. Task failure during exercise to exhaustion in normoxia and hypoxia is due to reduced muscle activation caused by central mechanisms while muscle metaboreflex does not limit performance

    Directory of Open Access Journals (Sweden)

    Rafael eTorres-Peralta

    2016-01-01

    Full Text Available To determine whether task failure during incremental exercise to exhaustion (IE is principally due to reduced neural drive and increased metaboreflex activation eleven men (22±2 years performed a 10s control isokinetic sprint (IS; 80 rpm after a short warm-up. This was immediately followed by an IE in normoxia (Nx, PIO2:143 mmHg and hypoxia (Hyp, PIO2:73 mmHg in random order, separated by a 120 min resting period. At exhaustion, the circulation of both legs was occluded instantaneously (300 mmHg during 10 or 60s to impede recovery and increase metaboreflex activation. This was immediately followed by an IS with open circulation. Electromyographic recordings were obtained from the vastus medialis and lateralis. Muscle biopsies and blood gases were obtained in separate experiments. During the last 10s of the IE, pulmonary ventilation, VO2, power output and muscle activation were lower in hypoxia than in normoxia, while pedaling rate was similar. Compared to the control sprint, performance (IS-Wpeak was reduced to a greater extent after the IE-Nx (11% lower P<0.05 than IE-Hyp. The root mean square (EMGRMS was reduced by 38 and 27% during IS performed after IE-Nx and IE-Hyp, respectively (Nx vs. Hyp: P<0.05. Post-ischemia IS-EMGRMS values were higher than during the last 10s of IE. Sprint exercise mean (IS-MPF and median (IS-MdPF power frequencies, and burst duration, were more reduced after IE-Nx than IE-Hyp (P<0.05. Despite increased muscle lactate accumulation, acidification, and metaboreflex activation from 10 to 60s of ischemia, IS-Wmean (+23% and burst duration (+10% increased, while IS-EMGRMS decreased (-24%, P<0.05, with IS-MPF and IS-MdPF remaining unchanged. In conclusion, close to task failure, muscle activation is lower in hypoxia than in normoxia. Task failure is predominantly caused by central mechanisms, which recover to great extent within one minute even when the legs remain ischemic. There is dissociation between the recovery of

  2. Delivery strategies to optimize resource utilization and performance status for patients with advanced life-limiting illness: results from the "palliative care trial" [ISRCTN 81117481].

    Science.gov (United States)

    Abernethy, Amy P; Currow, David C; Shelby-James, Tania; Rowett, Debra; May, Frank; Samsa, Gregory P; Hunt, Roger; Williams, Helena; Esterman, Adrian; Phillips, Paddy A

    2013-03-01

    Evidence-based approaches are needed to improve the delivery of specialized palliative care. The aim of this trial was to improve on current models of service provision. This 2×2×2 factorial cluster randomized controlled trial was conducted at an Australian community-based palliative care service, allowing three simultaneous comparative effectiveness studies. Participating patients were newly referred adults, experiencing pain, and who were expected to live >48 hours. Patients enrolled with their general practitioners (GPs) and were randomized three times: 1) individualized interdisciplinary case conference including their GP vs. control, 2) educational outreach visiting for GPs about pain management vs. control, and 3) structured educational visiting for patients/caregivers about pain management vs. control. The control condition was current palliative care. Outcomes included Australia-modified Karnofsky Performance Status (AKPS) and pain from 60 days after randomization and hospitalizations. There were 461 participants: mean age 71 years, 50% male, 91% with cancer, median survival 179 days, and median baseline AKPS 60. Only 47% of individuals randomized to the case conferencing intervention received it; based on a priori-defined analyses, 32% of participants were included in final analyses. Case conferencing reduced hospitalizations by 26% (least squares means hospitalizations per patient: case conference 1.26 [SE 0.10] vs. control 1.70 [SE 0.13], P=0.0069) and better maintained performance status (AKPS case conferences 57.3 [SE 1.5] vs. control 51.7 [SE 2.3], P=0.0368). Among patients with declining function (AKPS performance status (AKPS case conferences 55.0 [SE 2.1] vs. control 46.5 [SE 2.9], P=0.0143; patient/caregiver education 54.7 [SE 2.8] vs. control 46.8 [SE 2.1], P=0.0206). Pain was unchanged. GP education did not change outcomes. A single case conference added to current specialized community-based palliative care reduced hospitalizations and better

  3. Creativity and working memory capacity in sports: working memory capacity is not a limiting factor in creative decision making amongst skilled performers.

    Science.gov (United States)

    Furley, Philip; Memmert, Daniel

    2015-01-01

    The goal of the study was to investigate the relationship between domain-general working memory capacity and domain-specific creativity amongst experienced soccer players. We administered the automated operation span task in combination with a domain-specific soccer creativity task to a group of 61 experienced soccer players to address the question whether an athlete's domain-specific creativity is restricted by their domain-general cognitive abilities (i.e., working memory capacity). Given that previous studies have either found a positive correlation, a negative correlation, or no correlation between working memory capacity and creativity, we analyzed the data in an exploratory manner by following recent recommendations to report effect-size estimations and their precision in form of 95% confidence intervals. The pattern of results provided evidence that domain-general working memory capacity is not associated with creativity in a soccer-specific creativity task. This pattern of results suggests that future research and theorizing on the role of working memory in everyday creative performance needs to distinguish between different types of creative performance while also taking the role of domain-specific experience into account.

  4. SLC kicker magnet limitations

    International Nuclear Information System (INIS)

    Cassel, R.; Donaldson, A.; Mattison, T.; Bowden, G.; Weaver, J.; Bulos, F.; Fiander, D.

    1991-01-01

    The SLC Damping Ring kicker magnets requires a fast magnetic field rise time of 58 nsec, a peak field of 800 gauss, a pulse amplitude stability of 0.01%, and a reasonable operational lifetime. The original kicker magnets designed by SLAC and at Fermi were not able to fulfill the SLC kicker requirements. Extensive studies were conducted to determine the limitation in the magnets, response of the ferrite in kicker magnet, and the modifications needed to improve the kicker magnet performance. The paper details the SLAC and Fermi kicker magnets limitation of performance

  5. Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves

    Science.gov (United States)

    Chang, S. S.; Lohakare, J. D.; Singh, N. K.; Kwon, E. G.; Nejad, J. G.; Sung, K. I.; Hong, S. K.

    2013-01-01

    This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age) divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay) was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW) were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061) only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (pcalves in the control group had higher concentrate and lower forage intake than the restricted group. The plasma variables like total protein and urea were higher (pfeeding schemes during early growth for beef calves is not advocated. PMID:25049777

  6. Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves

    Directory of Open Access Journals (Sweden)

    S. S. Chang

    2013-02-01

    Full Text Available This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061 only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (p<0.01. As planned, the calves in the control group had higher concentrate and lower forage intake than the restricted group. The plasma variables like total protein and urea were higher (p<0.05 in control than restricted group. The mRNA expressions for the gluconeogenic enzymes such as cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32 and pyruvate carboxylase (EC 6.4.1.1, and

  7. Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves.

    Science.gov (United States)

    Chang, S S; Lohakare, J D; Singh, N K; Kwon, E G; Nejad, J G; Sung, K I; Hong, S K

    2013-02-01

    This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age) divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay) was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW) were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061) only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (pforage intake than the restricted group. The plasma variables like total protein and urea were higher (p<0.05) in control than restricted group. The mRNA expressions for the gluconeogenic enzymes such as cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1), and visfatin measured by quantitative real-time PCR in liver biopsies showed higher expression (p<0.05) in

  8. Multiplex real-time quantitative PCR, microscopy and rapid diagnostic immuno-chromatographic tests for the detection of Plasmodium spp: performance, limit of detection analysis and quality assurance

    Directory of Open Access Journals (Sweden)

    Ralevski Filip

    2009-12-01

    Full Text Available Abstract Background Accurate laboratory diagnosis of malaria species in returning travelers is paramount in the treatment of this potentially fatal infectious disease. Materials and methods A total of 466 blood specimens from returning travelers to Africa, Asia, and South/Central America with suspected malaria infection were collected between 2007 and 2009 at the reference public health laboratory. These specimens were assessed by reference microscopy, multipex real-time quantitative polymerase chain reaction (QPCR, and two rapid diagnostic immuno-chromatographic tests (ICT in a blinded manner. Key clinical laboratory parameters such as limit of detection (LOD analysis on clinical specimens by parasite stage, inter-reader variability of ICTs, staffing implications, quality assurance and cost analysis were evaluated. Results QPCR is the most analytically sensitive method (sensitivity 99.41%, followed by CARESTART (sensitivity 88.24%, and BINAXNOW (sensitivity 86.47% for the diagnosis of malaria in returning travelers when compared to reference microscopy. However, microscopy was unable to specifically identify Plasmodia spp. in 18 out of 170 positive samples by QPCR. Moreover, the 17 samples that were negative by microscopy and positive by QPCR were also positive by ICTs. Quality assurance was achieved for QPCR by exchanging a blinded proficiency panel with another reference laboratory. The Kappa value of inter-reader variability among three readers for BINAXNOW and CARESTART was calculated to be 0.872 and 0.898 respectively. Serial dilution studies demonstrated that the QPCR cycle threshold correlates linearly with parasitemia (R2 = 0.9746 in a clinically relevant dynamic range and retains a LOD of 11 rDNA copies/μl for P. falciparum, which was several log lower than reference microscopy and ICTs. LOD for QPCR is affected not only by parasitemia but the parasite stage distribution of each clinical specimen. QPCR was approximately 6-fold more

  9. An optimist's view on limiting necrotic enteritis and maintaining broiler gut health and performance in today's marketing, food safety, and regulatory climate.

    Science.gov (United States)

    Hofacre, Charles L; Smith, John A; Mathis, Greg F

    2018-06-01

    The future poultry nutritionist, veterinarian, and husbandryman will have many new regulatory requirements and consumer preferences to navigate in addition to their normal responsibility of raising birds in a cost-efficient and wholesome manner. New challenges include changes to antibiotic use, increased food safety regulations, and more concern over how birds are raised and how to dispose of poultry house waste. All of these new programs and new regulations will alter how we have been raising birds for the last 60 years since the inception of the integrated poultry industry. The most significant change may be the voluntary or regulatory withdrawal of the use of antibiotics in poultry production. In North America, this withdrawal of antibiotic use includes removal of in-ovo antibiotics, performance-improving antibiotics or antibiotic growth promotors (AGP), and the polyether ionophore antibiotics (ionophore anticoccidials).The removal of antibiotics in poultry production may result in welfare concerns due to elevated mortality and less efficient feed conversion, resulting in greater environmental impacts from increased manure production and more use of grain per unit of meat produced. There also may be concerns with greater intestinal disease in the birds resulting in increased numbers of foodborne illness-causing bacteria such as Salmonella sp. or Campylobacter sp. on the carcass. A major impact will be the disease necrotic enteritis (NE). This review will focus on the pathophysiology of NE, the management of the disease, and the additional effects on growth rate, feed efficiency, and body weight that may be associated with NE.

  10. Tokamak pump limiters

    International Nuclear Information System (INIS)

    Conn, R.W.; California Univ., Los Angeles

    1984-01-01

    Recent experiments with a scoop limiter without active internal pumping have been carried out in the PDX tokamak with up to 6 MW of auxiliary neutral beam heating. Experiments have also been performed with a rotating head pump limiter in the PLT tokamak in conjunction with RF plasma heating. Extensive experiments have been done in the ISX-B tokamak and first experiments have been completed with the ALT-I limiter in TEXTOR. The pump limiter modules in these latter two machines have internal getter pumping. Experiments in ISX-B are with ohmic and auxiliary neutral beam heating. The results in ISX-B and TEXTOR show that active density control and particle removal is achieved with pump limiters. In ISX-B, the boundary layer (or scrape-off layer) plasma partially screens the core plasma from gas injection. In both ISX-B and TEXTOR, the pressure internal to the module scales linearly with plasma density but in ISX-B, with neutral beam injection, a nonlinear increase is observed at the highest densities studied. Plasma plugging is the suspected cause. Results from PDX suggest that a regime may exist in which core plasma energy confinement improves using a pump limiter during neutral beam injection. Asymmetric radial profiles and an increased edge electron temperature are observed in discharges with improved confinement. The injection of small amounts of neon into ISX-B has more clearly shown an improved electron core energy confinement during neutral beam injection. While carried out with a regular limiter, this 'Z-mode' of operation is ideal for use with pump limiters and should be a way to achieve energy confinement times similar to values for H-mode tokamak plasmas. The implication of all these results for the design of a reactor pump limiter is described. (orig.)

  11. Hadron collider luminosity limitations

    CERN Document Server

    Evans, Lyndon R

    1992-01-01

    The three colliders operated to date have taught us a great deal about the behaviour of both bunched and debunched beams in storage rings. The main luminosity limitations are now well enough understood that most of them can be stronglu attenuated or eliminated by approriate design precautions. Experience with the beam-beam interaction in both the SPS and the Tevatron allow us to predict the performance of the new generation of colliders with some degree of confidence. One of the main challenges that the accelerator physicist faces is the problem of the dynamic aperture limitations due to the lower field quality expected, imposed by economic and other constraints.

  12. Linear Controller Design: Limits of Performance

    Science.gov (United States)

    1991-01-01

    which converges to khk as T So for large T and H stable so that kHkpk gn the signal yields kzk kwk near khk it is also...possible to show that there is a signal w such that kzk kwk khk 98 CHAPTER 5 NORMS OF SYSTEMS The peak gain of a system can also be expressed in terms...jHjj Sw and therefore kzk rms Z Sz d Z jHjjSw d sup jHjj Z Sw d kHkkwk rms

  13. INAA - application and limitation

    International Nuclear Information System (INIS)

    Heydorn, K.

    1990-01-01

    The uncertainties associated with performing Instrumental Neutron Activation Analysis (INAA) are discussed in relation to their category. The Comite International de Poids et Mesure (CIPM) distinguishes between uncertainties according to how their contribution to the overall uncertainty is evaluated. INAA is a potentially definitive method, if all sources of uncertainty can be accounted for. The limitation of the method is reached when uncertainties, which cannot be accounted for, assume significance, and the method cannot be brought in statistical control. (orig.)

  14. Interference and memory capacity limitations.

    Science.gov (United States)

    Endress, Ansgar D; Szabó, Szilárd

    2017-10-01

    Working memory (WM) is thought to have a fixed and limited capacity. However, the origins of these capacity limitations are debated, and generally attributed to active, attentional processes. Here, we show that the existence of interference among items in memory mathematically guarantees fixed and limited capacity limits under very general conditions, irrespective of any processing assumptions. Assuming that interference (a) increases with the number of interfering items and (b) brings memory performance to chance levels for large numbers of interfering items, capacity limits are a simple function of the relative influence of memorization and interference. In contrast, we show that time-based memory limitations do not lead to fixed memory capacity limitations that are independent of the timing properties of an experiment. We show that interference can mimic both slot-like and continuous resource-like memory limitations, suggesting that these types of memory performance might not be as different as commonly believed. We speculate that slot-like WM limitations might arise from crowding-like phenomena in memory when participants have to retrieve items. Further, based on earlier research on parallel attention and enumeration, we suggest that crowding-like phenomena might be a common reason for the 3 major cognitive capacity limitations. As suggested by Miller (1956) and Cowan (2001), these capacity limitations might arise because of a common reason, even though they likely rely on distinct processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. FTU pump limiter

    International Nuclear Information System (INIS)

    Alessandrini, C.; Ciotti, M.; Mattei, A. De; Maddaluno, G.; Mazzitelli, G.

    1989-01-01

    The control of the refuelling and recycling of the plasma is crucial in providing enhanced performances in tokamaks and steady-state operation in future reactors. In this paper, we report details of the design and analysis for the pump limiter to be incorporated into the FTU tokamak. The FTU, presently under commissioning, is a compact high field (B=8T), medium high density, circular cross section machine with small accesses. The dimensions of the equatorial port (width 8 cm) would reduce the length of the entrance throat to a few centimeters, which is unacceptable for efficient particle trapping. We have, therefore, designed a rotating blade of the pump limiter head that, in the working position, extends in the toroidal direction inside the vacuum chamber. (author) 8 refs., 4 figs

  16. Income trusts and limited partnerships

    International Nuclear Information System (INIS)

    Toews, E.L.

    1999-01-01

    This author provided a conceptual overview of income trusts and limited partnerships that are designed to pass operating cash flow directly to investors without the imposition of corporate taxes, discussed the evolution of the market, the mechanism used to price income funds, past and present performance of the sector, and made some predictions concerning the sector's future performance. 13 figs

  17. Partnerships – Limited partnerships and limited liability limited partnerships

    OpenAIRE

    Henning, Johan J.

    2000-01-01

    Consideration of the Limited Liability Partnership Act 2000 which introduced a new corporate entity, carrying the designations “partnership” and “limited” which allow members to limit their liability whilst organising themselves internally as a partnership. Article by Professor Johan Henning (Director of the Centre for Corporate Law and Practice, IALS and Dean of the Faculty of Law, University of the Free State, South Africa). Published in Amicus Curiae - Journal of the Institute of Advanced ...

  18. Preliminary disposal limits, plume interaction factors, and final disposal limits

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2018-01-11

    In the 2008 E-Area Performance Assessment (PA), each final disposal limit was constructed as the product of a preliminary disposal limit and a plume interaction factor. The following mathematical development demonstrates that performance objectives are generally expected to be satisfied with high confidence under practical PA scenarios using this method. However, radionuclides that experience significant decay between a disposal unit and the 100-meter boundary, such as H-3 and Sr-90, can challenge performance objectives, depending on the disposed-of waste composition, facility geometry, and the significance of the plume interaction factor. Pros and cons of analyzing single disposal units or multiple disposal units as a group in the preliminary disposal limits analysis are also identified.

  19. HOME Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — HOME Income Limits are calculated using the same methodology that HUD uses for calculating the income limits for the Section 8 program. These limits are based on HUD...

  20. US ITER limiter module design

    International Nuclear Information System (INIS)

    Mattas, R.F.; Billone, M.; Hassanein, A.

    1996-08-01

    The recent U.S. effort on the ITER (International Thermonuclear Experimental Reactor) shield has been focused on the limiter module design. This is a multi-disciplinary effort that covers design layout, fabrication, thermal hydraulics, materials evaluation, thermo- mechanical response, and predicted response during off-normal events. The results of design analyses are presented. Conclusions and recommendations are also presented concerning, the capability of the limiter modules to meet performance goals and to be fabricated within design specifications using existing technology

  1. The Limits of Exercise Physiology

    DEFF Research Database (Denmark)

    Gabriel, Brendan M; Zierath, Juleen R

    2017-01-01

    Many of the established positive health benefits of exercise have been documented by historical discoveries in the field of exercise physiology. These investigations often assess limits: the limits of performance, or the limits of exercise-induced health benefits. Indeed, several key findings have...... been informed by studying highly trained athletes, in addition to healthy or unhealthy people. Recent progress has been made in regard to skeletal muscle metabolism and personalized exercise regimes. In this perspective, we review some of the historical milestones of exercise physiology, discuss how...

  2. Biased limiter experiments on text

    International Nuclear Information System (INIS)

    Phillips, P.E.; Wootton, A.J.; Rowan, W.L.; Ritz, C.P.; Rhodes, T.L.; Bengtson, R.D.; Hodge, W.L.; Durst, R.D.; McCool, S.C.; Richards, B.; Gentle, K.W.; Schoch, P.; Forster, J.C.; Hickok, R.L.; Evans, T.E.

    1987-01-01

    Experiments using an electrically biased limiter have been performed on the Texas Experimental Tokamak (TEXT). A small movable limiter is inserted past the main poloidal ring limiter (which is electrically connected to the vacuum vessel) and biased at V Lim with respect to it. The floating potential, plasma potential and shear layer position can be controlled. With vertical strokeV Lim vertical stroke ≥ 50 V the plasma density increases. For V Lim Lim > 0 the results obtained are inconclusive. Variation of V Lim changes the electrostatic turbulence which may explain the observed total flux changes. (orig.)

  3. Limits on fundamental limits to computation.

    Science.gov (United States)

    Markov, Igor L

    2014-08-14

    An indispensable part of our personal and working lives, computing has also become essential to industries and governments. Steady improvements in computer hardware have been supported by periodic doubling of transistor densities in integrated circuits over the past fifty years. Such Moore scaling now requires ever-increasing efforts, stimulating research in alternative hardware and stirring controversy. To help evaluate emerging technologies and increase our understanding of integrated-circuit scaling, here I review fundamental limits to computation in the areas of manufacturing, energy, physical space, design and verification effort, and algorithms. To outline what is achievable in principle and in practice, I recapitulate how some limits were circumvented, and compare loose and tight limits. Engineering difficulties encountered by emerging technologies may indicate yet unknown limits.

  4. Phenotypic variation in metabolism and morphology correlating with animal swimming activity in the wild: relevance for the OCLTT (oxygen- and capacity-limitation of thermal tolerance), allocation and performance models.

    Science.gov (United States)

    Baktoft, Henrik; Jacobsen, Lene; Skov, Christian; Koed, Anders; Jepsen, Niels; Berg, Søren; Boel, Mikkel; Aarestrup, Kim; Svendsen, Jon C

    2016-01-01

    Ongoing climate change is affecting animal physiology in many parts of the world. Using metabolism, the oxygen- and capacity-limitation of thermal tolerance (OCLTT) hypothesis provides a tool to predict the responses of ectothermic animals to variation in temperature, oxygen availability and pH in the aquatic environment. The hypothesis remains controversial, however, and has been questioned in several studies. A positive relationship between aerobic metabolic scope and animal activity would be consistent with the OCLTT but has rarely been tested. Moreover, the performance model and the allocation model predict positive and negative relationships, respectively, between standard metabolic rate and activity. Finally, animal activity could be affected by individual morphology because of covariation with cost of transport. Therefore, we hypothesized that individual variation in activity is correlated with variation in metabolism and morphology. To test this prediction, we captured 23 wild European perch (Perca fluviatilis) in a lake, tagged them with telemetry transmitters, measured standard and maximal metabolic rates, aerobic metabolic scope and fineness ratio and returned the fish to the lake to quantify individual in situ activity levels. Metabolic rates were measured using intermittent flow respirometry, whereas the activity assay involved high-resolution telemetry providing positions every 30 s over 12 days. We found no correlation between individual metabolic traits and activity, whereas individual fineness ratio correlated with activity. Independent of body length, and consistent with physics theory, slender fish maintained faster mean and maximal swimming speeds, but this variation did not result in a larger area (in square metres) explored per 24 h. Testing assumptions and predictions of recent conceptual models, our study indicates that individual metabolism is not a strong determinant of animal activity, in contrast to individual morphology, which is

  5. Limitations of Human Visual Working Memory

    OpenAIRE

    Wesenick, Maria-Barbara

    2004-01-01

    The present empirical study investigates limitations of human visual working memory (VWM). The experiments of the present work involve the experimental paradigm of change detection using simple geometrical objects in the form of rectangles of different colour, length, and orientation. It can be shown, that a limited performance in the temporary storage of visual information has multiple sources. Limitations of VWM can be attributed to a limited capacity or a limited duration, but also to limi...

  6. The biotin repressor: modulation of allostery by corepressor analogs.

    Science.gov (United States)

    Brown, Patrick H; Cronan, John E; Grøtli, Morten; Beckett, Dorothy

    2004-04-02

    The Escherichia coli biotin repressor functions in biotin retention and regulation of biotin biosynthesis. Biotin retention is accomplished via the two-step biotinylation of the biotin-dependent enzyme, acetyl-CoA carboxylase. In the first step of this reaction the substrates biotin and ATP are utilized in synthesis of the activated biotin, biotinyl-5'-AMP, while in the second step this activated biotin is transferred to a unique lysine residue of the biotin carboxyl carrier protein subunit of the carboxylase. Regulation of biotin biosynthesis is accomplished through binding of the repressor to the transcription control region of the biotin biosynthetic operon. The adenylated or activated biotin functions as the corepressor in this DNA binding process. The activated biotin is a mixed anhydride and thus labile. In efforts to develop tools for structural and thermodynamic studies of the biotin regulatory interactions, two analogs of the adenylate, a sulfamoyl derivative and an ester derivative, have been synthesized and functionally characterized. Results of fluorescence measurements indicate that both analogs bind with high affinity to the repressor and that both are inactive in biotin transfer to the acceptor protein. Functional studies of their corepressor properties indicate that while the sulfamoyl is a weak allosteric activator, the ester closely mimics the physiological corepressor in activation of assembly of the transcription repression complex. Results of these studies also provide further insight into the allosteric mechanism of the biotin repressor.

  7. CYP2E1 Metabolism of Styrene Involves Allostery

    Science.gov (United States)

    Hartman, Jessica H.; Boysen, Gunnar

    2012-01-01

    We are the first to report allosterism during styrene oxidation by recombinant CYP2E1 and human liver microsomes. At low styrene concentrations, oxidation is inefficient because of weak binding to CYP2E1 (Ks = 830 μM). A second styrene molecule then binds CYP2E1 with higher affinity (Kss = 110 μM) and significantly improves oxidation to achieve a kcat of 6.3 nmol · min−1 · nmol CYP2E1−1. The transition between these metabolic cycles coincides with reported styrene concentrations in blood from exposed workers; thus, this CYP2E1 mechanism may be relevant in vivo. Scaled modeling of the in vitro-positive allosteric mechanism for styrene metabolism to its in vivo clearance led to significant deviations from the traditional model based on Michaelis-Menten kinetics. Low styrene levels were notably much less toxic than generally assumed. We interrogated the allosteric mechanism using the CYP2E1-specific inhibitor and drug 4-methylpyrazole, which we have shown binds two CYP2E1 sites. From the current studies, styrene was a positive allosteric effector on 4-methylpyrazole binding, based on a 10-fold increase in 4-methylpyrazole binding affinity from Ki 0.51 to Ksi 0.043 μM. The inhibitor was a negative allosteric effector on styrene oxidation, because kcat decreased 6-fold to 0.98 nmol · min−1 · nmol CYP2E1−1. Consequently, mixtures of styrene and other molecules can induce allosteric effects on binding and metabolism by CYP2E1 and thus mitigate the efficiency of their metabolism and corresponding effects on human health. Taken together, our elucidation of mechanisms for these allosteric reactions provides a powerful tool for further investigating the complexities of CYP2E1 metabolism of drugs and pollutants. PMID:22807108

  8. Summary of Dissolved Concentration Limits

    International Nuclear Information System (INIS)

    Yueting Chen

    2001-01-01

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M and O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits

  9. Summary of Dissolved Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Yueting Chen

    2001-06-11

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M&O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits.

  10. Robust test limits

    NARCIS (Netherlands)

    Albers, Willem/Wim; Kallenberg, W.C.M.; Otten, G.D.

    1997-01-01

    Because of inaccuracies of the measurement process inspection of manufactured parts requires test limits which are more strict than the given specification limits. Test limits derived under the assumption of normality for product characteristics turn out to violate the prescribed bound on the

  11. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  12. Tokamak plasma interaction with limiters

    International Nuclear Information System (INIS)

    Pitcher, C.S.

    1987-11-01

    The importance of plasma purity is first discussed in terms of the general requirements of controlled thermonuclear fusion. The tokamak approach to fusion and its inherent problem of plasma contamination are introduced. A main source of impurities is due to the bombardment of the limiter by energetic particles and thus the three main aspects of the plasma-limiter interaction are reviewed, boundary plasma conditions, fuelling/recycling and impurity production. The experiments, carried out on the DITE tokamak at Culham Laboratory, UK, investigated these three topics and the results are compared with predicted behaviour; new physical phenomena are presented in all three areas. Simple one-dimensional fluid equations are found to adequately describe the SOL plasma, except in regard to the pre-sheath electric field and ambipolarity; that is, the electric field adjacent to the limiter surface appears to be weak and the associated plasma flow can be non-ambipolar. Recycling of fuel particles from the limiter is observed to be near unity at all times. The break-up behaviour of recycled and gas puffed D 2 molecules is dependent on the electron temperature, as expected. Impurity production at the limiter is chemical erosion of graphite being negligible. Deposition of limiter and wall-produced impurities is found on the limiter. The spatial distributions of impurities released from the limiter are observed and are in good agreement with a sputtered atom transport code. Finally, preliminary experiments on the transport of impurity ions along field lines away from the limiter have been performed and compared with simple analytic theory. The results suggest that the pre-sheath electric field in the SOL is much weaker than the simple fluid model would predict

  13. 7 CFR 1400.204 - Limited partnerships, limited liability partnerships, limited liability companies, corporations...

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Limited partnerships, limited liability partnerships..., limited liability partnerships, limited liability companies, corporations, and other similar legal entities. (a) A limited partnership, limited liability partnership, limited liability company, corporation...

  14. JET pump limiter

    International Nuclear Information System (INIS)

    Sonnenberg, K.; Deksnis, E.; Shaw, R.; Reiter, D.

    1988-01-01

    JET plans to install two pump limiter modules which can be used for belt-limiter, inner-wall and X-point discharges and, also, for 1-2s as the main limiter. A design is presented which is compatible with two diagnostic systems, and which allows partial removal of the pump limiter to provide access for remote-handling operations. The high heat-flux components are initially cooled during a pulse. Heat is removed between discharges by radiation and pressure contacts to a water-cooled support structure. The pumping edge will be made of annealed pyrolytic graphite. Exhaust efficiency has been estimated, for a 1-d edge model, using a Monte-Carlo calculation of neutral gas transport. When the pump limiter is operated together with other wall components we expect an efficiency of ≅ 5% (2.5 x 10 21 part/s). As a main limiter the efficiency increases to about 10%. (author)

  15. Reactor limit control system

    International Nuclear Information System (INIS)

    Rubbel, F.E.

    1982-01-01

    The very extensive use of limitations in the operational field between protection system and closed-loop controls is an important feature of German understanding of operational safety. The design of limitations is based on very large activities in the computational field but mostly on the high level of the plant-wide own commissioning experience of a turnkey contractor. Limitations combine intelligence features of closed-loop controls with the high availability of protection systems. (orig.)

  16. Detector limitations, STAR

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, D. G.

    1998-07-13

    Every detector has limitations in terms of solid angle, particular technologies chosen, cracks due to mechanical structure, etc. If all of the presently planned parts of STAR [Solenoidal Tracker At RHIC] were in place, these factors would not seriously limit our ability to exploit the spin physics possible in RHIC. What is of greater concern at the moment is the construction schedule for components such as the Electromagnetic Calorimeters, and the limited funding for various levels of triggers.

  17. Limit loads in nozzles

    International Nuclear Information System (INIS)

    Zouain, N.

    1983-01-01

    The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author) [pt

  18. Limit analysis via creep

    International Nuclear Information System (INIS)

    Taroco, E.; Feijoo, R.A.

    1981-07-01

    In this paper it is presented a variational method for the limit analysis of an ideal plastic solid. This method has been denominated as Modified Secundary Creep and enables to find the collapse loads through a minimization of a functional and a limit process. Given an ideal plastic material it is shown how to determinate the associated secundary creep constitutive equation. Finally, as an application, it is found the limit load in an pressurized von Mises rigid plastic sphere. (Author) [pt

  19. Numerical Limit Analysis:

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2007-01-01

    Limit State analysis has a long history and many prominent researchers have contributed. The theoretical foundation is based on the upper- and lower-bound theorems which give a very comprehensive and elegant formulation on complicated physical problems. In the pre-computer age Limit State analysis...... also enabled engineers to solve practical problems within reinforced concrete, steel structures and geotechnics....

  20. Advanced limiters for ISX

    International Nuclear Information System (INIS)

    Mioduszewski, P.K.; Edmonds, P.H.; Sheffield, J.

    1982-01-01

    Continuous removal of heat and particles becomes a vital necessity in future steady-state fusion devices. The pump limiter seems to be an attractive concept to combine these two tasks. On ISX, various schemes of pump limiters are being explored with the final goal to furnish the ISX--C device with a pump limiter to handle heat removal and particle control in steady state. The emphasis of the present paper is on pump limiters based on ballistic particle collection. If this concept turns out to be successful in supplying sufficient pumping efficiency, it may be possible to design pump limiters without a leading edge. Analytical calculations of the particle collection efficiency are given for various limiter configurations. Pumping efficiencies of approximately 4--10%, depending on the specific configuration, seem to be feasible and should be sufficient for steady-state operation. Initial experimental results on pump limiter studies in ISX--B confirm the calculated collection efficiencies. By measuring the ion saturation current to the limiter blade and the pressure buildup simultaneously, we found a correlation between the incident particle flux and the pressure rise that agrees well with a simple model

  1. Limits to Inclusion

    Science.gov (United States)

    Hansen, Janne Hedegaard

    2012-01-01

    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  2. Mitigating greenhouse: Limited time, limited options

    International Nuclear Information System (INIS)

    Moriarty, Patrick; Honnery, Damon

    2008-01-01

    Most human-caused climate change comes from fossil fuel combustion emissions. To avoid the risk of serious climate change, very recent research suggests that emission reductions will need to be both large and rapidly implemented. We argue that technical solutions-improving energy efficiency, use of renewable and nuclear energy, and carbon capture and sequestration-can only be of minor importance, mainly given the limited time available to take effective climate action. Only curbing energy use, perhaps through 'social efficiency' gains, particularly in the high-energy consumption countries, can provide the rapid emissions reductions needed. The social efficiency approach requires a basic rethinking in how we can satisfy our human needs with low environmental impacts. Large cuts in emissions could then occur rapidly, but only if resistance to such changes can be overcome. Particularly in transport, there are also serious potential conflicts between the technical and the social efficiency approaches, requiring a choice to be made

  3. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  4. Moving toroidal limiter

    International Nuclear Information System (INIS)

    Ikuta, Kazunari; Miyahara, Akira.

    1983-06-01

    The concept of the limiter-divertor proposed by Mirnov is extended to a toroidal limiter-divertor (which we call moving toroidal limiter) using the stream of ferromagnetic balls coated with a low Z materials such as plastics, graphite and ceramics. An important advantage of the use of the ferromagnetic materials would be possible soft landing of the balls on a catcher, provided that the temperature of the balls is below Curie point. Moreover, moving toroidal limiter would work as a protector of the first wall not only against the vertical movement of plasma ring but also against the violent inward motion driven by major disruption because the orbit of the ball in the case of moving toroidal limiter distributes over the small major radius side of the toroidal plasma. (author)

  5. Tokamak pump limiters

    International Nuclear Information System (INIS)

    Conn, R.W.

    1984-05-01

    Recent experiments with a scoop limiter without active internal pumping have been carried out in the PDX tokamak with up to 6MW of auxiliary neutral beam heating. Experiments have also been done with a rotating head pump limiter in the PLT tokamak in conjunction with RF plasma heating. Extensive experiments have been done in the ISX-B tokamak and first experiments have been completed with the ALT-I limiter in TEXTOR. The pump limiter modules in these latter two machines have internal getter pumping. Experiments in ISX-B are with ohmic and auxiliary neutral beam heating. The results in ISX-B and TEXTOR show that active density control and particle removal is achieved with pump limiters. In ISX-B, the boundary layer (or scape-off layer) plasma partially screens the core plasma from gas injection. In both ISX-B and TEXTOR, the pressure internal to the module scales linearly with plasma density but in ISX-B, with neutral beam injection, a nonlinear increase is observed at the highest densities studied. Plasma plugging is the suspected cause. Results from PDX suggest that a region may exist in which core plasma energy confinement improves using a pump limiter during neutral beam injection. Asymmetric radial profiles and an increased edge electron temperature are observed in discharges with improved confinement. The injection of small amounts of neon into ISX-B has more clearly shown an improved electron core energy confinement during neutral beam injection. While carried out with a regular limiter, this Z-mode of operation is ideal for use with pump limiters and should be a way to achieve energy confinement times similar to values for H-mode tokamak plasmas. The implication of all these results for the design of a reactor pump limiter is described

  6. Novel limiter pump topologies

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The use of limiter pumps as the principle plasma exhaust system of a magnetic confinement fusion device promises significant simplification, when compared to previously investigating divertor based systems. Further simplifications, such as the integration of the exhaust system with a radio frequency heating system and with the main reactor shield and structure are investigated below. The integrity of limiters in a reactor environment is threatened by many mechanisms, the most severe of which may be erosion by sputtering. Two novel topolgies are suggested which allow high erosion without limiter failure

  7. Novel limiter pump topologies

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The use of limiter pumps as the principle plasma exhaust system of a magnetic confinement fusion device promises significant simplification, when compared to previously investigating divertor based systems. Further simplifications, such as the integration of the exhaust system with a radio frequency heating system and with the main reactor shield and structure are investigated below. The integrity of limiters in a reactor environment is threatened by many mechanisms, the most severe of which may be erosion by sputtering. Two novel topologies are suggested which allow high erosion without limiter failure

  8. HUD Program Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — Income limits used to determine the income eligibility of applicants for assistance under three programs authorized by the National Housing Act. These programs are...

  9. Limited Income and Resources

    Data.gov (United States)

    U.S. Department of Health & Human Services — Information for those with limited income and resources (those who may qualify for or already have the Low Income Subsidy to lower their prescription drug coverage...

  10. SIS - Annual Catch Limit

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Annual Catch Limit (ACL) dataset within the Species Information System (SIS) contains information and data related to management reference points and catch data.

  11. Limited Denial of Participation

    Data.gov (United States)

    Department of Housing and Urban Development — A Limited Denial of Participation (LDP) is an action taken by a HUD Field Office or the Deputy Assistant Secretary for Single Family (DASSF) or Multifamily (DASMF)...

  12. Towards Improved Optical Limiters

    National Research Council Canada - National Science Library

    Huffman, Peter

    2002-01-01

    .... The first approach was to synthesize and study soluble thallium phthalocyanines. Thallium, due to its proximity to lead and indium on the periodic table, should exhibit favorable optical limiting properties...

  13. ACA Federal Upper Limits

    Data.gov (United States)

    U.S. Department of Health & Human Services — Affordable Care Act Federal Upper Limits (FUL) based on the weighted average of the most recently reported monthly average manufacturer price (AMP) for...

  14. HOME Rent Limits

    Data.gov (United States)

    Department of Housing and Urban Development — In accordance with 24 CFR Part 92.252, HUD provides maximum HOME rent limits. The maximum HOME rents are the lesser of: The fair market rent for existing housing for...

  15. Limit lines for risk

    International Nuclear Information System (INIS)

    Cox, D.C.; Baybutt, P.

    1982-01-01

    Approaches to the regulation of risk from technological systems, such as nuclear power plants or chemical process plants, in which potential accidents may result in a broad range of adverse consequences must take into account several different aspects of risk. These include overall or average risk, accidents posing high relative risks, the rate at which accident probability decreases with increasing accident consequences, and the impact of high frequency, low consequence accidents. A hypothetical complementary cumulative distribution function (CCDF), with appropriately chosen parametric form, meets all these requirements. The Farmer limit line, by contrast, places limits on the risks due to individual accident sequences, and cannot adequately account for overall risk. This reduces its usefulness as a regulatory tool. In practice, the CCDF is used in the Canadian nuclear licensing process, while the Farmer limit line approach, supplemented by separate qualitative limits on overall risk, is employed in the United Kingdom

  16. Adjusting estimative prediction limits

    OpenAIRE

    Masao Ueki; Kaoru Fueda

    2007-01-01

    This note presents a direct adjustment of the estimative prediction limit to reduce the coverage error from a target value to third-order accuracy. The adjustment is asymptotically equivalent to those of Barndorff-Nielsen & Cox (1994, 1996) and Vidoni (1998). It has a simpler form with a plug-in estimator of the coverage probability of the estimative limit at the target value. Copyright 2007, Oxford University Press.

  17. Smoothness of limit functors

    Indian Academy of Sciences (India)

    Abstract. Let S be a scheme. Assume that we are given an action of the one dimen- sional split torus Gm,S on a smooth affine S-scheme X. We consider the limit (also called attractor) subfunctor Xλ consisting of points whose orbit under the given action. 'admits a limit at 0'. We show that Xλ is representable by a smooth ...

  18. Safety and design limits

    International Nuclear Information System (INIS)

    Shishkov, L. K.; Gorbaev, V. A.; Tsyganov, S. V.

    2007-01-01

    The paper touches upon the issues of NPP safety ensuring at the stage of fuel load design and operation by applying special limitations for a series of parameters, that is, design limits. Two following approaches are compared: the one used by west specialists for the PWR reactor and the Russian approach employed for the WWER reactor. The closeness of approaches is established, differences that are mainly peculiarities of terms are noted (Authors)

  19. Altruism and Reproductive Limitations

    Directory of Open Access Journals (Sweden)

    Carey J. Fitzgerald

    2009-04-01

    Full Text Available We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia, physical (malnutrition, and sexual (bisexuality and homosexuality — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50. Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

  20. The Augmented Performer and the Performative Augmentation

    DEFF Research Database (Denmark)

    Kallionpaa, Maria; Gasselseder, Hans-Peter

    2016-01-01

    Composers, performers, and listeners usually regard musical compositions as unchangeable entities, which limits the composition techniques and decreases the originality of performers ́ interpretations, thus leading to a stagnation of classical music culture. The significance and possibilities of ...

  1. Force Limit System

    Science.gov (United States)

    Pawlik, Ralph; Krause, David; Bremenour, Frank

    2011-01-01

    The Force Limit System (FLS) was developed to protect test specimens from inadvertent overload. The load limit value is fully adjustable by the operator and works independently of the test system control as a mechanical (non-electrical) device. When a test specimen is loaded via an electromechanical or hydraulic test system, a chance of an overload condition exists. An overload applied to a specimen could result in irreparable damage to the specimen and/or fixturing. The FLS restricts the maximum load that an actuator can apply to a test specimen. When testing limited-run test articles or using very expensive fixtures, the use of such a device is highly recommended. Test setups typically use electronic peak protection, which can be the source of overload due to malfunctioning components or the inability to react quickly enough to load spikes. The FLS works independently of the electronic overload protection.

  2. Theory of limit cycles

    CERN Document Server

    Ye, Yan-Qian; Lo, Chi Y

    1986-01-01

    Over the past two decades the theory of limit cycles, especially for quadratic differential systems, has progressed dramatically in China as well as in other countries. This monograph, updating the 1964 first edition, includes these recent developments, as revised by eight of the author's colleagues in their own areas of expertise. The first part of the book deals with limit cycles of general plane stationary systems, including their existence, nonexistence, stability, and uniqueness. The second section discusses the global topological structure of limit cycles and phase-portraits of quadratic systems. Finally, the last section collects important results that could not be included under the subject matter of the previous two sections or that have appeared in the literature very recently. The book as a whole serves as a reference for college seniors, graduate students, and researchers in mathematics and physics.

  3. Density limit experiments on FTU

    International Nuclear Information System (INIS)

    Pucella, G.; Tudisco, O.; Apicella, M.L.; Apruzzese, G.; Artaserse, G.; Belli, F.; Boncagni, L.; Botrugno, A.; Buratti, P.; Calabrò, G.; Castaldo, C.; Cianfarani, C.; Cocilovo, V.; Dimatteo, L.; Esposito, B.; Frigione, D.; Gabellieri, L.; Giovannozzi, E.; Bin, W.; Granucci, G.

    2013-01-01

    One of the main problems in tokamak fusion devices concerns the capability to operate at a high plasma density, which is observed to be limited by the appearance of catastrophic events causing loss of plasma confinement. The commonly used empirical scaling law for the density limit is the Greenwald limit, predicting that the maximum achievable line-averaged density along a central chord depends only on the average plasma current density. However, the Greenwald density limit has been exceeded in tokamak experiments in the case of peaked density profiles, indicating that the edge density is the real parameter responsible for the density limit. Recently, it has been shown on the Frascati Tokamak Upgrade (FTU) that the Greenwald density limit is exceeded in gas-fuelled discharges with a high value of the edge safety factor. In order to understand this behaviour, dedicated density limit experiments were performed on FTU, in which the high density domain was explored in a wide range of values of plasma current (I p = 500–900 kA) and toroidal magnetic field (B T = 4–8 T). These experiments confirm the edge nature of the density limit, as a Greenwald-like scaling holds for the maximum achievable line-averaged density along a peripheral chord passing at r/a ≃ 4/5. On the other hand, the maximum achievable line-averaged density along a central chord does not depend on the average plasma current density and essentially depends on the toroidal magnetic field only. This behaviour is explained in terms of density profile peaking in the high density domain, with a peaking factor at the disruption depending on the edge safety factor. The possibility that the MARFE (multifaced asymmetric radiation from the edge) phenomenon is the cause of the peaking has been considered, with the MARFE believed to form a channel for the penetration of the neutral particles into deeper layers of the plasma. Finally, the magnetohydrodynamic (MHD) analysis has shown that also the central line

  4. Analysis of forming limit in tube hydroforming

    International Nuclear Information System (INIS)

    Kim, Chan Il; Yang, Seung Hang; Kim, Young Suk

    2013-01-01

    The automotive industry has shown increasing interest in tube hydroforming. Despite many automobile structural parts being produced from cylindrical tubes, failures frequently occur during tube hydroforming under improper forming conditions. These problems include wrinkling, buckling, folding back, and bursting. We perform analytical studies to determine forming limits in tube hydroforming and demonstrate how these forming limits are influenced by the loading path. Theoretical results for the forming limits of wrinkling and bursting are compared with experimental results for an aluminum tube.

  5. The quasi-abelian limit

    International Nuclear Information System (INIS)

    Fried, H.M.; Avan, J.

    2000-01-01

    A new, non-perturbative, eikonal method called the ''quasi abelian limit'' (QAL) is suggested for high energy quark (nucleon) scattering involving the exchange of all possible, non-interacting, non-abelian gluons (mesons). With this method, those functional integrals defining, e.g., the exchange of color coordinates in quark-quark scattering, are replaced by a finite number of quadratures over a subset of their coordinates. Mathematically, this procedure is not rigourous, because an unjustified interchange of limits has been performed; physically, it corresponds to the observation that the non-perturbative sum over all color-moment fluctuations can vanish at arbitrarily high energies. The QAL generates a result in agreement with a corrected, ''contiguity'' calculation, when the latter is summed over all perturbative orders. (orig.)

  6. 14 CFR 183.55 - Limitations.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS REPRESENTATIVES OF THE ADMINISTRATOR Organization Designation Authorization § 183.55 Limitations... structure), no Unit member may perform that function until the Administrator is notified of the change, and...

  7. Activation analysis. Detection limits

    International Nuclear Information System (INIS)

    Revel, G.

    1999-01-01

    Numerical data and limits of detection related to the four irradiation modes, often used in activation analysis (reactor neutrons, 14 MeV neutrons, photon gamma and charged particles) are presented here. The technical presentation of the activation analysis is detailed in the paper P 2565 of Techniques de l'Ingenieur. (A.L.B.)

  8. Thermal background noise limitations

    Science.gov (United States)

    Gulkis, S.

    1982-01-01

    Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

  9. The Copyright Agency Limited.

    Science.gov (United States)

    Morgan, Caroline

    1993-01-01

    The evolution and functions of Australia's Copyright Agency Limited are described. The agency is a copyright collecting organization which collectively administers the rights of authors and publishers whose works are copied in education, and enters into blanket agreements with educational authorities outside the existing statutory license. Some…

  10. Occupational dose equivalent limits

    International Nuclear Information System (INIS)

    Goldfinch, E.P.

    1980-01-01

    This paper considers methods of limiting individual radiation risks by recognizing the variation of risk with age at exposure, taking into account both somatic and genetic risks and proposes a simple formula for controlling individual cumulative exposure and hence risk. (Author)

  11. The Limits of Accountability.

    Science.gov (United States)

    Bailey, Stephen K.

    This discussion, presented at the Regent's Trustees' Conference, February 1973, reviews the limits of accountability in higher education. Managerial efficiency is suggested to assist in eliminating educational and financial waste. This, however, is the secondary concept emphasized. The primary emphasis indicates the legitimacy of the claims that a…

  12. Limitations of shallow nets approximation.

    Science.gov (United States)

    Lin, Shao-Bo

    2017-10-01

    In this paper, we aim at analyzing the approximation abilities of shallow networks in reproducing kernel Hilbert spaces (RKHSs). We prove that there is a probability measure such that the achievable lower bound for approximating by shallow nets can be realized for all functions in balls of reproducing kernel Hilbert space with high probability, which is different with the classical minimax approximation error estimates. This result together with the existing approximation results for deep nets shows the limitations for shallow nets and provides a theoretical explanation on why deep nets perform better than shallow nets. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Phenotypic variation in metabolism and morphology correlating with animal swimming activity in the wild: relevance for the OCLTT (oxygen- and capacity-limitation of thermal tolerance), allocation and performance models

    DEFF Research Database (Denmark)

    Baktoft, Henrik; Jacobsen, Lene; Skov, Christian

    2016-01-01

    Ongoing climate change is affecting animal physiology in many parts of the world. Using metabolism, the oxygen- and capacitylimitation of thermal tolerance (OCLTT) hypothesis provides a tool to predict the responses of ectothermic animals to variation in temperature, oxygen availability and p......H in the aquatic environment. The hypothesis remains controversial, however, and has been questioned in several studies. A positive relationship between aerobic metabolic scope and animal activity would be consistent with the OCLTT but has rarely been tested. Moreover, the performance model and the allocation...... model predict positive and negative relationships, respectively, between standard metabolic rate and activity. Finally, animal activity could be affected by individual morphology because of covariation with cost of transport. Therefore, we hypothesized that individual variation in activity is correlated...

  14. Petite motorisation et exploitations maraîchères de taille limitée du Sahel tunisien Partie 2: Evaluation sur le terrain des performances et des coûts de préparation du sol

    Directory of Open Access Journals (Sweden)

    Chehaibi, S.

    2003-01-01

    Full Text Available Low Power Mechanisation and Small-scale Vegetable Production in the Tunisian Sahel Region. Part 2: On the Field Evaluation of Performances and of Soil Preparation Costs. In this study, it was investigated to what extent low power mechanisation could be introduced in vegetable production in the Tunisian Sahel region by evaluating its performance (labour input and field efficiency by means of field experiments in which different traction equipment was used for carrying out several cultivation operations. Furthermore, costs per unit area for soil preparation in both sandy clay and clayish sand were calculated for four different power classes and for small fields. The results showed that two wheel tractors had a real labour input for scuffling between plant rows ranging from 11.3 h/ha to 18.7 h/ha. These inputs ranged from 5.5 h/ha to 6.7 h/ha for tied crops. For mowing, the two wheel tractor had labour inputs of 17.3 and 14.2 h/ha for the first and the second cut, respectively, while for potato digging, the first and the second passage of secondary tillage these values were 11.5, 14.3 and 10.4 h/ha, respectively. Superficial soil preparation by means of a four wheel tractor gave rise to values between 2.7 and 3.5 h/ha. With respect to the cost estimation for soil preparation, the lowest costs were obtained by means of the low power mechanisation. Similar conclusions were drawn for the field efficiencies for the operations investigated. In general, these efficiencies were above 70%.

  15. Age Limit of Pediatrics.

    Science.gov (United States)

    Hardin, Amy Peykoff; Hackell, Jesse M

    2017-09-01

    Pediatrics is a multifaceted specialty that encompasses children's physical, psychosocial, developmental, and mental health. Pediatric care may begin periconceptionally and continues through gestation, infancy, childhood, adolescence, and young adulthood. Although adolescence and young adulthood are recognizable phases of life, an upper age limit is not easily demarcated and varies depending on the individual patient. The establishment of arbitrary age limits on pediatric care by health care providers should be discouraged. The decision to continue care with a pediatrician or pediatric medical or surgical subspecialist should be made solely by the patient (and family, when appropriate) and the physician and must take into account the physical and psychosocial needs of the patient and the abilities of the pediatric provider to meet these needs. Copyright © 2017 by the American Academy of Pediatrics.

  16. Current limiter circuit system

    Science.gov (United States)

    Witcher, Joseph Brandon; Bredemann, Michael V.

    2017-09-05

    An apparatus comprising a steady state sensing circuit, a switching circuit, and a detection circuit. The steady state sensing circuit is connected to a first, a second and a third node. The first node is connected to a first device, the second node is connected to a second device, and the steady state sensing circuit causes a scaled current to flow at the third node. The scaled current is proportional to a voltage difference between the first and second node. The switching circuit limits an amount of current that flows between the first and second device. The detection circuit is connected to the third node and the switching circuit. The detection circuit monitors the scaled current at the third node and controls the switching circuit to limit the amount of the current that flows between the first and second device when the scaled current is greater than a desired level.

  17. Limits of Nuclear Stability

    CERN Document Server

    Nerlo-Pomorska, B; Kleban, M

    2003-01-01

    The modern version of the liquid-drop model (LSD) is compared with the macroscopic part of the binding energy evaluated within the Hartree-Fock- Bogoliubov procedure with the Gogny force and the relativistic mean field theory. The parameters of a liquid-drop like mass formula which approximate on the average the self-consistent results are compared with other models. The limits of nuclear stability predicted by these models are discussed.

  18. Are Limit Orders Rational?

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Martin

    2007-01-01

    Roč. 14, č. 4 (2007), s. 32-38 ISSN 0572-3043 R&D Projects: GA ČR(CZ) GA402/06/1417; GA ČR GA402/04/1294; GA ČR GD402/03/H057 Institutional research plan: CEZ:AV0Z10750506 Keywords : market microstructure * limit order market * portfolio selection Subject RIV: AH - Economics

  19. Density limits in Tokamaks

    International Nuclear Information System (INIS)

    Tendler, M.

    1984-06-01

    The energy loss from a tokamak plasma due to neutral hydrogen radiation and recycling is of great importance for the energy balance at the periphery. It is shown that the requirement for thermal equilibrium implies a constraint on the maximum attainable edge density. The relation to other density limits is discussed. The average plasma density is shown to be a strong function of the refuelling deposition profile. (author)

  20. Photovoltaic energy cost limit

    International Nuclear Information System (INIS)

    Coiante, D.

    1992-01-01

    Referring to a photovoltaic system for grid connected applications, a parametric expression of kWh cost is derived. The limit of kWh cost is carried out extrapolating the values of cost components to their lowest figure. The reliability of the forecast is checked by disaggregating kWh cost in direct and indirect costs and by discussing the possible cost reduction of each component

  1. Heat flux limiting sleeves

    Science.gov (United States)

    Harris, William G.

    1985-01-01

    A heat limiting tubular sleeve extending over only a portion of a tube having a generally uniform outside diameter, the sleeve being open on both ends, having one end thereof larger in diameter than the other end thereof and having a wall thickness which decreases in the same direction as the diameter of the sleeve decreases so that the heat transfer through the sleeve and tube is less adjacent the large diameter end of the sleeve than adjacent the other end thereof.

  2. HEDIS Limited Data Set

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Healthcare Effectiveness Data and Information Set (HEDIS) is a tool used by more than 90 percent of Americas health plans to measure performance on important...

  3. Superconductive AC current limiter

    International Nuclear Information System (INIS)

    Bekhaled, M.

    1987-01-01

    This patent describes an AC current limiter for a power transport line including a power supply circuit and feeding a load circuit via an overload circuit-breaker member. The limiter comprises a transformer having a primary winding connected in series between the power supply circuit and the load circuit and at least one secondary winding of superconductor material contained in a cryogenic enclosure and short-circuited on itself. The leakage reactance of the transformer as seen from the primary winding is low, and the resistance of the at least one secondary winding when in the non-superconducting state and as seen from the primary is much greater than the nominal impedance of the transformer. The improvement whereby the at least one secondary winding of the transformer comprises an active winding in association with a set of auxiliary windings. The set of auxiliary windings is constituted by an even number of series-connected auxiliary windings wound in opposite directions, with the total number of turns in one direction being equal to the total number of turns in the opposite direction, and with the thermal capacity of the secondary winding as a whole being sufficiently high to limit the expansion thereof to a value which remains small during the time it takes the circuit-breaking member to operate

  4. The applicability and limitations of the geochemical models and tools used in simulating radionuclide behaviour in natural waters. Lessons learned from the Blind Predictive Modelling exercises performed in conjunction with Natural Analogue studies

    International Nuclear Information System (INIS)

    Bruno, J.; Duro, L.; Grive, M.

    2001-07-01

    One of the key applications of Natural Analogue studies to the Performance Assessment (PA) of nuclear waste disposal has been the possibility to test the geochemical models and tools to be used in describing the migration of radionuclides in a future radioactive waste repository system. To this end, several geochemical modelling testing exercises (commonly denoted as Blind Predictive Modelling), have formed an integral part of Natural Analogue Studies over the last decade. Consequently, we thought that this is a timely occasion to make an evaluation of the experience gained and lessons learnt. We have reviewed, discussed and compared the results obtained from the Blind Prediction Modelling (BPM) exercises carried out within 7 Natural Analogue Studies: Oman, Pocos de Caldas, Cigar Lake, Maqarin, El Berrocal, Oklo and Palmottu. To make this comparison meaningful, we present the main geochemical characteristics of each site in order to highlight the most relevant mineralogical and hydrochemical differences. From the complete list of elements studied at all the investigated sites we have made a selection based on the relevance of a given element from a PA viewpoint and on the frequency this element has been included in the BPM exercises. The elements selected for discussion are: Sr, Ba, Sn, Pb, Se, Ni, Zn, REEs, Th and U. We have based our discussion on the results obtained from the speciation as well as solubility calculations. From the comparison of the results it is concluded that we can differentiate between three element categories: 1. Elements whose geochemical behaviour can be fairly well described by assuming solubility control exerted by pure solid phases of the given element (i.e. Th, U under reducing conditions and U in some sites under oxidising conditions); 2. Elements for which the association to major geochemical components of the system must be considered in order to explain their concentrations in groundwaters (i.e. Sr, Ba, Zn, Se, REEs and U under

  5. Waste tank characterization sampling limits

    International Nuclear Information System (INIS)

    Tusler, L.A.

    1994-01-01

    This document is a result of the Plant Implementation Team Investigation into delayed reporting of the exotherm in Tank 241-T-111 waste samples. The corrective actions identified are to have immediate notification of appropriate Tank Farm Operations Shift Management if analyses with potential safety impact exceed established levels. A procedure, WHC-IP-0842 Section 12.18, ''TWRS Approved Sampling and Data Analysis by Designated Laboratories'' (WHC 1994), has been established to require all tank waste sampling (including core, auger and supernate) and tank vapor samples be performed using this document. This document establishes levels for specified analysis that require notification of the appropriate shift manager. The following categories provide numerical values for analysis that may indicate that a tank is either outside the operating specification or should be evaluated for inclusion on a Watch List. The information given is intended to translate an operating limit such as heat load, expressed in Btu/hour, to an analysis related limit, in this case cesium-137 and strontium-90 concentrations. By using the values provided as safety flags, the analytical laboratory personnel can notify a shift manager that a tank is in potential violation of an operating limit or that a tank should be considered for inclusion on a Watch List. The shift manager can then take appropriate interim measures until a final determination is made by engineering personnel

  6. Strategic arms limitation

    Science.gov (United States)

    Allen Greb, G.; Johnson, Gerald W.

    1983-10-01

    Following World War II, American scientists and politicians proposed in the Baruch plan a radical solution to the problem of nuclear weapons: to eliminate them forever under the auspices of an international nuclear development authority. The Soviets, who as yet did not possess the bomb, rejected this plan. Another approach suggested by Secretary of War Henry Stimson to negotiate directly with the Soviet Union was not accepted by the American leadership. These initial arms limitation failures both reflected and exacerbated the hostile political relationship of the superpowers in the 1950s and 1960s. Since 1969, the more modest focus of the Soviet-American arms control process has been on limiting the numbers and sizes of both defensive and offensive strategic systems. The format for this effort has been the Strategic Arms Limitatins Talks (Salt) and more recently the Strategic Arms Reduction Talks (START). Both sides came to these negotiations convinced that nuclear arsenals had grown so large that some for of mutual restraint was needed. Although the SALT/START process has been slow and ponderous, it has produced several concrete the agreements and collateral benefits. The 1972 ABM Treaty restricts the deployment of ballistic missile defense systems, the 1972 Interim Agreement places a quantitative freeze on each side's land based and sea based strategic launchers, and the as yet unratified 1979 SALT II Treaty sets numerical limits on all offensive strategic systems and sublimits on MIRVed systems. Collateral benefits include improved verification procedures, working definitions and counting rules, and permanent bureaucratic apparatus which enhance stability and increase the chances for achieving additional agreements.

  7. Beta limits for ETF

    International Nuclear Information System (INIS)

    Helton, F.J.; Miller, R.L.

    1982-01-01

    ETF (Engineering Test Facility) one-dimensional transport simulations indicate that a volume-average beta of 4% is required for ignition. It is therefore important that theoretical beta limits, determined by requiring equilibria to be stable to all ideal modes, exceed 4%. This paper documents an ideal MHD analysis wherein it is shown that, with appropriate plasma cross-sectional shape and current profile optimization, operation near 5% is possible. The critical beta value, however, depends on the functional form used for ff', which suggests that higher critical betas could be achieved by directly optimizing the safety factor profile. (author)

  8. Limitations of Boltzmann's principle

    International Nuclear Information System (INIS)

    Lavenda, B.H.

    1995-01-01

    The usual form of Boltzmann's principle assures that maximum entropy, or entropy reduction, occurs with maximum probability, implying a unimodal distribution. Boltzmann's principle cannot be applied to nonunimodal distributions, like the arcsine law, because the entropy may be concave only over a limited portion of the interval. The method of subordination shows that the arcsine distribution corresponds to a process with a single degree of freedom, thereby confirming the invalidation of Boltzmann's principle. The fractalization of time leads to a new distribution in which arcsine and Cauchy distributions can coexist simultaneously for nonintegral degrees of freedom between √2 and 2

  9. Fault current limiter

    Science.gov (United States)

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  10. Dose. Detriment. Limit assessment

    International Nuclear Information System (INIS)

    Breckow, J.

    2015-01-01

    One goal of radiation protection is the limitation of stochastic effects due to radiation exposure. The probability of occurrence of a radiation induced stochastic effect, however, is only one of several other parameters which determine the radiation detriment. Though the ICRP-concept of detriment is a quantitative definition, the kind of detriment weighting includes somewhat subjective elements. In this sense, the detriment-concept of ICRP represents already at the stage of effective dose a kind of assessment. Thus, by comparing radiation protection standards and concepts interconvertible or with those of environment or occupational protection one should be aware of the possibly different principles of detriment assessment.

  11. Marketing with limited budget

    OpenAIRE

    Smirnova, Daria

    2017-01-01

    The purpose of this research-based thesis was to get an idea how managers of two small resembling hotels of a specific region deal with marketing process with a limited budget. In addition, the aim of the thesis was to examine if hotel managers who were interviewed perceive marketing only in the way of ‘promotion’ rather than marketing research, marketing mix and marketing environment theories. It was also found out if hotel managers of those hotels consider marketing as a key to successful h...

  12. Limitation of Auditors' Liability

    DEFF Research Database (Denmark)

    Werlauff, Erik; Foged-Ladefoged, Lise Kolding

    2014-01-01

    The article examines the question of whether rules on the limitation of auditors’ liability within the perspective of EU law are needed, and if so, which rules can provide an appropriate balance between the potential injured party’s interests and those of the auditing sector, including with respect...... to the fact that the insurance premiums associated with an unlimited liability must of course make the auditor’s tasks more expensive. Relevant EU recommendations and a comparative glance at other EU countries’ proposed solutions to the problem are included....

  13. Limits to biofuels

    Directory of Open Access Journals (Sweden)

    Johansson S.

    2013-06-01

    Full Text Available Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays’ use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years’ agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2–6000TWh (biogas from residues and waste and ethanol from woody biomass in the more optimistic cases.

  14. Limits to biofuels

    Science.gov (United States)

    Johansson, S.

    2013-06-01

    Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays' use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years' agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2-6000TWh (biogas from residues and waste and ethanol from woody biomass) in the more optimistic cases.

  15. (Limiting the greenhouse effect)

    Energy Technology Data Exchange (ETDEWEB)

    Rayner, S.

    1991-01-07

    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  16. Limitations of inclusive fitness.

    Science.gov (United States)

    Allen, Benjamin; Nowak, Martin A; Wilson, Edward O

    2013-12-10

    Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.

  17. The limitation and modification of flux-limited diffusion theory

    International Nuclear Information System (INIS)

    Liu Chengan; Huang Wenkai

    1986-01-01

    The limitation of various typical flux-limited diffusion theory and advantages of asymptotic diffusion theory with time absorption constant are analyzed and compared. The conclusions are as following: Though the flux-limited problem in neutron diffusion theory are theoretically solved by derived flux-limited diffusion equation, it's going too far to limit flux due to the inappropriate assumption in deriving flux-limited diffusion equation. The asymptotic diffusion theory with time absorption constant has eliminated the above-mentioned limitation, and it is more accurate than flux-limited diffusion theory in describing neutron transport problem

  18. Limits of Lubrication in

    DEFF Research Database (Denmark)

    Olsson, David Dam

    as delivered stainless steel surfaces implying microstructure changes in terms of larger ratio of closed lubricant pockets due to selective grain boundary etching. Strategic surfaces have also been created by macroscopic texturing using spherical indentations having a very small edge slope in order to promote...... by strategic surfaces in comparison to normal stainless steel surfaces implying a larger extent of bi-axial stretching. Numerical simulations have been applied in order to evaluate limits of lubrication in the simulative strip reduction based on predictions of critical parameters appearing in terms......-models corresponds well to experimental results in terms of lubricant film breakdown and subsequently pick-up development. Punching and blanking have been investigated regarding tribological conditions in case of using stainless steel workpiece materials. However, this has called for development of a new test method...

  19. Personal Freedom beyond Limits

    Directory of Open Access Journals (Sweden)

    Juan Fernando Sellés

    2013-07-01

    Full Text Available In this work we distinguish between freedom in the human manifestations (intelligence, will,actions and personal freedom in the personal intimacy. This second is beyond the freedom reached bythe classic and modern thought, since it takes root in the personnel act of being. Because of it, it is not possible to characterize this freedom like the classic description as ‘domain over the own acts’, becauseit is a description of ‘categorial’ order; neither like present day ‘autonomy’ or ‘independence’, becausethe existence of one person alone is impossible, since ‘person’ means relation, personal free openingto other persons, description of the ‘transcendental’ order and, therefore, to the margin of limits.

  20. [Does medicine limit enlightenment?].

    Science.gov (United States)

    Schipperges, H

    1977-01-01

    In the first, historical part the most important programs of "Medical Enlightenment", are pointed out, beginning with Leibniz, followed by the public health movement of the 18th century, up to the time of Immanuel Kant. Based on this historical background several concepts of a "Medical Culture" are analysed in detail, for instance the "Theorie einer Medizinal-Ordnung" by Johann Benjamin Ehrhard (1800), the "Medicinische Reform" by Rudolf Virchow (1848) and the programs of the "Gesellschaft Deutscher Naturforscher und Arzte" (about 1850-1890), the latter bearing both scientific and political character. Following the historical part, the question is raised whether "Enlightenment" is limited by medicine and whether medicine is able to provide a program for individual health education resulting in a more cultivated style of private life, and lastly how this might be realized.

  1. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  2. Modular pump limiter systems for large tokamaks

    International Nuclear Information System (INIS)

    Uckan, T.; Klepper, C.C.; Mioduszewski, P.K.; McGrath, R.T.

    1987-09-01

    Long-pulse (>10-s) operation of large tokamaks with high-power (>10-MW) heating and extensive external fueling will require correspondingly efficient particle exhaust for density control. A pump limiter can provide the needed exhaust capability by removing a small percentage of the particles, which would otherwise be recycled. Single pump limiter modules have been operated successfully on ISX-B, PDX, TEXTOR, and PLT. An axisymmetric pump limiter is now being installed and will be studied in TEXTOR. A third type of pump limiter is a system that consists of several modules and exhibits performance different from that of a single module. To take advantage of the flexibility of a modular pump limiter system in a high-power, long-pulse device, the power load must be distributed among a number of modules. Because each added module changes the performance of all the others, a set of design criteria must be defined for the overall limiter system. The design parameters for the modules are then determined from the system requirements for particle and power removal. Design criteria and parameters are presented, and the impact on module design of the state of the art in engineering technology is discussed. The relationship between modules are considered from the standpoint of flux coverage and shadowing effects. The results are applied to the Tore Supra tokamak. A preliminary conceptual design for the Tore Supra pump limiter system is discussed, and the design parameters of the limiter modules are presented. 21 refs., 12 figs

  3. Limits to power system growth

    International Nuclear Information System (INIS)

    Slater, S.M.; Klein, A.C.; Webb, B.J.; Pauley, K.A.

    1993-01-01

    In the design of space nuclear power systems a variety of conversion techniques may be used, each with its own advantages and disadvantages. A study was performed which analyzed over 120 proposed system designs. The designs were compared to identify the optimum conversion system as a function of power level and find limits to specific mass (kg/kWe) for each power cycle. Furthermore, the component masses were studied to determine which component of the overall design contributes the most to total system mass over a variety of power levels. The results can provide a focus for future research efforts by selecting the best conversion technology for the desired power range, and optimizing the system component which contributes most to the total mass

  4. [Limitation of the therapeutic effort].

    Science.gov (United States)

    Herreros, B; Palacios, G; Pacho, E

    2012-03-01

    The limitation of the therapeutic effort (LTE) consists in not applying extraordinary or disproportionate measures for therapeutic purposes that are proposed for a patient with poor life prognosis and/or poor quality of life. There are two types. The first is to not initiate certain measures or to withdraw them when they are established. A decision of the LTE should be based on some rigorous criteria, so that we make the following proposal. First, it is necessary to know the most relevant details of the case to make a decision: the preferences of the patient, the preferences of the family when pertinent, the prognosis (severity), the quality of life and distribution of the limited resources. After, the decision should be made. In this phase, participatory deliberation should be established to clarify the end of the intervention. Finally, if it is decided to perform an LTE, it should be decided how to do it. Special procedures, disproportionate measures, that are useless and vain should not be initiated for the therapeutic objective designed (withdraw them if they have been established). When it has been decided to treat a condition (interim measures), the treatment should be maintained. This complex phase may need stratification of he measures. Finally, the necessary palliative measures should be established. Copyright © 2011 Elsevier España, S.L. All rights reserved.

  5. Limit, breakthrough and prosperity

    International Nuclear Information System (INIS)

    Takahashi, Minoru

    1973-01-01

    It is pointed out that the flow toward serious crises is in progress with regard to energy and industrial problems. Technical and industrial preparation and countermeasure to the flow are proposed, and the existence of a certain new world attainable on the assumption that the countermeasure is successful is described. The relation between oil output and the increasing demand for energy is pointed out as a subject matter of the crisis. The contribution of oil energy to total energy, after the output turns to decreasing process, decreases by 177.87x10 6 tons (converted to coal at the rate 6848 kcal/kg) per year at maximum. Converted to the GNP of the world, this becomes (425 dollar/ton x 177.87 x 10 6 ton=75.6 x 10 9 dollar). This fluctuation width in a year must be compensated by the change of industrial structure and energy supplying means. The countermeasure and preparation are proposed from the viewpoints of the energy and the industrial structure in which nuclear power generation plays important role. The largest production on the earth limited by energy consumption and the temperature balance on the earth is investigated, and the perspective in the future is given. (Yamamoto, Y.)

  6. What value, detection limits

    International Nuclear Information System (INIS)

    Currie, L.A.

    1986-01-01

    Specific approaches and applications of LLD's to nuclear and ''nuclear-related'' measurements are presented in connection with work undertaken for the U.S. Nuclear Regulatory Commission and the International Atomic Energy Agency. In this work, special attention was given to assumptions and potential error sources, as well as to different types of analysis. For the former, the authors considered random and systematic error associated with the blank and the calibration and sample preparation processes, as well as issues relating to the nature of the random error distributions. Analysis types considered included continuous monitoring, ''simple counting'' involving scalar quantities, and spectrum fitting involving data vectors. The investigation of data matrices and multivariate analysis is also described. The most important conclusions derived from this study are: that there is a significant lack of communication and compatibility resulting from diverse terminology and conceptual bases - including no-basis ''ad hoc'' definitions; that the distinction between detection decisions and detection limits is frequently lost sight of; and that quite erroneous LOD estimates follow from inadequate consideration of the actual variability of the blank, and systematic error associated with the blank, the calibration-recovery factor, matrix effects, and ''black box'' data reduction models

  7. Physical limits of silicon transistors and circuits

    International Nuclear Information System (INIS)

    Keyes, Robert W

    2005-01-01

    A discussion on transistors and electronic computing including some history introduces semiconductor devices and the motivation for miniaturization of transistors. The changing physics of field-effect transistors and ways to mitigate the deterioration in performance caused by the changes follows. The limits of transistors are tied to the requirements of the chips that carry them and the difficulties of fabricating very small structures. Some concluding remarks about transistors and limits are presented

  8. Performance Limitations in High-Energy Ion Colliders

    CERN Document Server

    Fischer, Wolfram

    2005-01-01

    High-energy ion colliders (hadron colliders operating with species other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. However, the experiments also expect flexibility with frequent changes in the collision energy, lattice configuration, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams, attention must be paid to space charge, charge exchange, and intra-beam scattering effects. The latter leads to luminosity lifetimes of only a few hours for heavy ions. Ultimately cooling at full energy is needed to overcome this effect. Currently, the Relativistic Heavy Ion Collider at BNL is the only operating high-energy ion collider. The Large Hadron Collider, under construction at CERN, will also run with heavy ions.

  9. Limitations and mechanisms influencing the migratory performance of soaring birds

    Science.gov (United States)

    Tricia A. Miller; Brooks Robert P.; Michael J. Lanzone; David Brandes; Jeff Cooper; Junior A. Tremblay; Jay Wilhelm; Adam Duerr; Todd E. Katzner

    2016-01-01

    Migration is costly in terms of time, energy and safety. Optimal migration theory suggests that individual migratory birds will choose between these three costs depending on their motivation and available resources. To test hypotheses about use of migratory strategies by large soaring birds, we used GPS telemetry to track 18 adult, 13 sub-adult and 15 juvenile Golden...

  10. 10 CFR 63.342 - Limits on performance assessments.

    Science.gov (United States)

    2010-01-01

    ... of climate change, and the resulting transport and release of radionuclides to the accessible environment. The nature and degree of climate change may be represented by constant-in-time climate conditions... biosphere, atmosphere, or ground water. (2) DOE must assess the effects of climate change. The climate...

  11. FCC-ee accelerator parameters, performance and limitations

    CERN Document Server

    Koratzinos, Mike

    2016-12-22

    CERN has recently launched the Future Circular Collider (FCC) study to deal with all aspects of an ambitious post-LHC possible programme. The emphasis of the study is on a 100 TeV proton collider to be housed in a 80-100 km new ring in the Geneva region. An electron machine will also be considered as a possible intermediate first step (FCC-ee). The study benefits from earlier work done in the context of TLEP and has already published a parameter table, to serve as the basis for the work to be done. The study aims to publish a conceptual design report at around 2018. The recent discovery of a light Higgs boson has opened up considerable interest in circular e+e- Higgs factories around the world. FCC-ee is capable of very high luminosities in a wide centre-of-mass (ECM) spectrum from 90 to 350 GeV. This allows the very precise study of the Z, W and H bosons as well as the top quark, allowing for meaningful precision tests of the closure of the Standard Model.

  12. What limits the performance of current invasive Brain Machine Interfaces?

    Directory of Open Access Journals (Sweden)

    Gytis eBaranauskas

    2014-04-01

    Full Text Available The concept of a brain-machine interface (BMI or a computer-brain interface is simple: BMI creates a communication pathway for a direct control by brain of an external device. In reality BMIs are very complex devices and only recently the increase in computing power of microprocessors enabled a boom in BMI research that continues almost unabated to this date, the high point being the insertion of electrode arrays into the brains of 5 human patients in a clinical trial run by Cyberkinetics with few other clinical tests still in progress. Meanwhile several EEG-based BMI devices (non-invasive BMIs were launched commercially. Modern electronics and dry electrode technology made possible to drive the cost of some of these devices below few hundred dollars. However, the initial excitement of the direct control by brain waves of a computer or other equipment is dampened by large efforts required for learning, high error rates and slow response speed. All these problems are directly related to low information transfer rates typical for such EEG-based BMIs. In invasive BMIs employing multiple electrodes inserted into the brain one may expect much higher information transfer rates than in EEG-based BMIs because, in theory, each electrode provides an independent information channel. However, although invasive BMIs require more expensive equipment and have ethical problems related to the need to insert electrodes in the live brain, such financial and ethical costs are often not offset by a dramatic improvement in the information transfer rate. Thus the main topic of this review is why in invasive BMIs an apparently much larger information content obtained with multiple extracellular electrodes does not translate into much higher rates of information transfer? This paper explores possible answers to this question by concluding that more research on what movement parameters are encoded by neurons in motor cortex is needed before we can enjoy the next generation BMIs.

  13. Performance Limits and Opportunities for Low Temperature Thermal Desalination

    OpenAIRE

    Nayar, Kishor Govind; Swaminathan, Jaichander; Warsinger, David Elan Martin; Lienhard, John H.

    2015-01-01

    Conventional low temperature thermal desalination (LTTD) uses ocean thermal temperature gradients to drive a single stage flash distillation process to produce pure water from seawater. While the temperature difference in the ocean drives distillation and provides cooling in LTTD, external electrical energy is required to pump the water streams from the ocean and to maintain a near vacuum in the flash chamber. In this work, an LTTD process from the literature is compared against, the thermody...

  14. Performance benefits and limitations of a camera network

    Science.gov (United States)

    Carr, Peter; Thomas, Paul J.; Hornsey, Richard

    2005-06-01

    Visual information is of vital significance to both animals and artificial systems. The majority of mammals rely on two images, each with a resolution of 107-108 'pixels' per image. At the other extreme are insect eyes where the field of view is segmented into 103-105 images, each comprising effectively one pixel/image. The great majority of artificial imaging systems lie nearer to the mammalian characteristics in this parameter space, although electronic compound eyes have been developed in this laboratory and elsewhere. If the definition of a vision system is expanded to include networks or swarms of sensor elements, then schools of fish, flocks of birds and ant or termite colonies occupy a region where the number of images and the pixels/image may be comparable. A useful system might then have 105 imagers, each with about 104-105 pixels. Artificial analogs to these situations include sensor webs, smart dust and co-ordinated robot clusters. As an extreme example, we might consider the collective vision system represented by the imminent existence of ~109 cellular telephones, each with a one-megapixel camera. Unoccupied regions in this resolution-segmentation parameter space suggest opportunities for innovative artificial sensor network systems. Essential for the full exploitation of these opportunities is the availability of custom CMOS image sensor chips whose characteristics can be tailored to the application. Key attributes of such a chip set might include integrated image processing and control, low cost, and low power. This paper compares selected experimentally determined system specifications for an inward-looking array of 12 cameras with the aid of a camera-network model developed to explore the tradeoff between camera resolution and the number of cameras.

  15. Sources for high frequency heating. Performance and limitations

    International Nuclear Information System (INIS)

    Le Gardeur, R.

    1976-01-01

    The various problems encountered in high frequency heating of plasmas can be decomposed into three spheres of action: theoretical development, antenna designing, and utilization of power sources. By classifying heating into three spectral domains, present and future needs are enumerated. Several specific antenna designs are treated. High frequency power sources are reviewed. The actual development of the gyratron is discussed in view of future needs in very high frequency heating of plasmas [fr

  16. fm threshold and methods of limiting its effect on performance

    African Journals Online (AJOL)

    SAMSON BRIGHT ONYEDIKACHI

    Non-coherent detection schemes are characterized by this. Noise ni (t) BPF ... R C. G d. Y t. G K V t. n t. K A dt π. = +. (9) or. 4. () 2. (). (). f m i. Y t. G K V t n t π. = +. (10) ..... p.337. 10. M.A. Ahaneku. NIGERIAN JOURNAL OF TECHNOLOGY, VOL.

  17. Performance of injection-limited polymer light-emitting diodes

    NARCIS (Netherlands)

    Blom, P.W.M.; Woudenberg, T.V.; Huiberts, H.; Jabbour, GE; Carter, SA; Kido, J; Lee, ST; Sariciftci, NS

    2002-01-01

    The electro-optical characteristics of a polymer light emitting diode (PLED) with a strongly reduced hole injection have been investigated. The device consists of a poly-p-phenylene vinylene semiconductor with a Ag hole injecting contact, which has an injection barrier of about 1 eV. It is observed

  18. Limitations imposed by wearing armour on Medieval soldiers' locomotor performance

    OpenAIRE

    Askew, Graham N.; Formenti, Federico; Minetti, Alberto E.

    2011-01-01

    In Medieval Europe, soldiers wore steel plate armour for protection during warfare. Armour design reflected a trade-off between protection and mobility it offered the wearer. By the fifteenth century, a typical suit of field armour weighed between 30 and 50 kg and was distributed over the entire body. How much wearing armour affected Medieval soldiers' locomotor energetics and biomechanics is unknown. We investigated the mechanics and the energetic cost of locomotion in armour, and determined...

  19. Model for movement of molten limiter material during the ISX-B beryllium limiter experiment

    International Nuclear Information System (INIS)

    Langley, R.A.; England, A.C.; Edmonds, P.H.; Hogan, J.T.; Neilson, G.H.

    1986-01-01

    A model is proposed for the movement and erosion of limiter material during the Beryllium Limiter Experiment performed on the ISX-B Tokamak. This model is consistent with observed experimental results and plasma operational characteristics. Conclusions drawn from the model can provide an understanding of erosion mechanisms, thereby contributing to the development of future design criteria. (author)

  20. The limits of deterrence

    International Nuclear Information System (INIS)

    Tertrais, Bruno

    2009-01-01

    The objective of this contribution is to propose a better insight of the validity of the theory of deterrence, and of related doctrines in more complex and more various situations than in the past: emergence of powers like China and India, of new nuclear States like North Korea and Pakistan, of countries planning to acquire nuclear weapons like Iran, and possibility of a new wave of nuclear proliferation in Middle-East and north-eastern Asia. It also aims at providing arguments in the debates on the struggle against nuclear proliferation and on the future of deterrence. The author first presents and comments the principles of deterrence, and illustrates them by more or less recent historical situations (Iran during the war with Iraq, USA after Pearl Harbour, Arab-Israeli wars, Iraq, and so on). He notably outlines that the notion of deterrence is present in Islamic culture, and that Iran has well integrated it in its defence strategy. Examples of statements and behaviours of other Arab leaders are discussed. The author also briefly indicates how the deterrence strategy is present in the official doctrines of Russia, India, Pakistan, and North Korea. In a second part, based on various examples, the author analyses the practical limitations of deterrence by distinguishing the psychological dimension (bounded rationality, political leaders suffering from various psychological problems, importance of the ideological and spiritual dimension, values prevailing on interests, the case of Iran), and the strategic dimension (good understanding of the enemy, sensitivity of the threat of massive damages, existence of a single decision centre and of an efficient communication). The author finally proposes seven recommendations for better deterrence efficiency

  1. Over the limit.

    Science.gov (United States)

    Qu, G

    1989-01-01

    With over 1 billion population, China is adding some 15 million to that total each year. And in the 18 years from 1982 to 2000, the net increase of Chinese population is expected to exceed 200 million. Because of the gigantic pressure from population and some mistakes in policies, the levels of ecological destruction and environment pollution are both serious. This includes deforestation, grassland degradation, desert encroachment, water resources shortage, and waste of mineral resources. Natural disasters including floods and droughts caused by those problems happen more and more frequently. If development damages the resource base, it can only result in a false prosperity, the so-called hollow economy. A large number of environmental problems result directly or indirectly from the pressure of population growth. Studies show that the appropriate number of people that can be supported by China's 9.6 million sq. km is about 700 million. However, this limit is now exceeded by over 300 million people, and will be exceeded by 500 million by the end of this century. Therefore, the task is to implement a birth control policy. At present, in urban areas, the goal of family planning has been reached, but in rural areas hard work is needed. Population control in urban areas, especially in big and medium-sized cities, includes dealing with the inflow of migrants from the countryside. There are 13 cities with a population above 2 million, 37 cities above 1-2 million, and 75 cities above 0.5-1 million. A lot of cities are very crowded, exerting great pressure on the environment. The booming of rural enterprises could provide a good solution to control the flow of rural people into big and medium-sized cities. The relationship between population, resources, environment, and development should be managed properly.

  2. Limits to Nonlinear Inversion

    DEFF Research Database (Denmark)

    Mosegaard, Klaus

    2012-01-01

    For non-linear inverse problems, the mathematical structure of the mapping from model parameters to data is usually unknown or partly unknown. Absence of information about the mathematical structure of this function prevents us from presenting an analytical solution, so our solution depends on our......-heuristics are inefficient for large-scale, non-linear inverse problems, and that the 'no-free-lunch' theorem holds. We discuss typical objections to the relevance of this theorem. A consequence of the no-free-lunch theorem is that algorithms adapted to the mathematical structure of the problem perform more efficiently than...... pure meta-heuristics. We study problem-adapted inversion algorithms that exploit the knowledge of the smoothness of the misfit function of the problem. Optimal sampling strategies exist for such problems, but many of these problems remain hard. © 2012 Springer-Verlag....

  3. Limited Investigation of the Effects of Elevator Rate Limiting and Stick Dynamics on Longitudinal Pilot Induced Oscillations (HAVE GRIP)

    National Research Council Canada - National Science Library

    Peters, Patrick

    1996-01-01

    This report presents the results of the HAVE GRIP flight test program. This program performed a limited investigation of the effects of stick dynamics and elevator rate limiting on longitudinal pilot induced oscillations (PIOs...

  4. Performing Performance Design Anglonationally

    DEFF Research Database (Denmark)

    2016-01-01

    Video recording of pecha kucha style bricolage aural enactment of an international version of performance design......Video recording of pecha kucha style bricolage aural enactment of an international version of performance design...

  5. Limitation on Bell's inequality

    Energy Technology Data Exchange (ETDEWEB)

    Buonomano, V [Universidade Estadual de Campinas (Brazil). Inst. de Matematica

    1978-01-01

    It is shown that Bell's Inequality does not characterize all local hidden variable explanations of the polarization correlation experiments. If one considers theories in which a single polarization measurement is not independent of previous particle-polarizer interactions then it is possible to manufacture local hidden variable theories which agree with quantum mechanics for any of the experiments performed to date. A relevant property here is ergodicity, and we can say that Bell's Inequality characterizes all ergodic local hidden variable theories (i.e., all local theories that give the same time and ensemble average) but not all non-ergodic local hidden variable theories. It is further shown that the most physically reasonable class of non-ergodic local hidden variable theories must also satisfy Bell's Inequality. It might be concluded from this article that if one insists on believing in both local hidden variable theories and the polarization correlation experiments supporting quantum mechanics then one must also believe in the existence of a field, medium or ether that permeates space and has relatively stable states (memory).

  6. The limits of subfunctionalization

    Directory of Open Access Journals (Sweden)

    Bergman Aviv

    2007-11-01

    Full Text Available Abstract Background The duplication-degeneration-complementation (DDC model has been proposed as an explanation for the unexpectedly high retention of duplicate genes. The hypothesis proposes that, following gene duplication, the two gene copies degenerate to perform complementary functions that jointly match that of the single ancestral gene, a process also known as subfunctionalization. We distinguish between subfunctionalization at the regulatory level and at the product level (e.g within temporal or spatial expression domains. Results In contrast to what is expected under the DDC model, we use in silico modeling to show that regulatory subfunctionalization is expected to peak and then decrease significantly. At the same time, neofunctionalization (recruitment of novel interactions increases monotonically, eventually affecting the regulatory elements of the majority of genes. Furthermore, since this process occurs under conditions of stabilizing selection, there is no need to invoke positive selection. At the product level, the frequency of subfunctionalization is no higher than would be expected by chance, a finding that was corroborated using yeast microarray time-course data. We also find that product subfunctionalization is not necessarily caused by regulatory subfunctionalization. Conclusion Our results suggest a more complex picture of post-duplication evolution in which subfunctionalization plays only a partial role in conjunction with redundancy and neofunctionalization. We argue that this behavior is a consequence of the high evolutionary plasticity in gene networks.

  7. Limits of detection and decision. Part 4

    International Nuclear Information System (INIS)

    Voigtman, E.

    2008-01-01

    Probability density functions (PDFs) have been derived for a number of commonly used limit of detection definitions, including several variants of the Relative Standard Deviation of the Background-Background Equivalent Concentration (RSDB-BEC) method, for a simple linear chemical measurement system (CMS) having homoscedastic, Gaussian measurement noise and using ordinary least squares (OLS) processing. All of these detection limit definitions serve as both decision and detection limits, thereby implicitly resulting in 50% rates of Type 2 errors. It has been demonstrated that these are closely related to Currie decision limits, if the coverage factor, k, is properly defined, and that all of the PDFs are scaled reciprocals of noncentral t variates. All of the detection limits have well-defined upper and lower limits, thereby resulting in finite moments and confidence limits, and the problem of estimating the noncentrality parameter has been addressed. As in Parts 1-3, extensive Monte Carlo simulations were performed and all the simulation results were found to be in excellent agreement with the derived theoretical expressions. Specific recommendations for harmonization of detection limit methodology have also been made

  8. FED pumped limiter configuration issues

    International Nuclear Information System (INIS)

    Haines, J.R.; Fuller, G.M.

    1983-01-01

    Impurity control in the Fusion Engineering Device (FED) is provided by a toroidal belt pumped limiter. Limiter design issues addressed in this paper are (1) poloidal location of the limiter belt, (2) shape of the limiter surface facing the plasma, and (3) whether the belt is pumped from one or both sides. The criteria used for evaluation of limiter configuration features were sensitivity to plasma-edge conditions and ease of maintenance and fabrication. The evaluation resulted in the selection of a baseline FED limiter that is located at the bottom of the device and has a flat surface with a single leading edge

  9. FED pumped limiter configuration issues

    International Nuclear Information System (INIS)

    Haines, J.R.; Fuller, G.M.

    1983-01-01

    Impurity control in the Fusion Engineering Device (FED) is provided by a toroidal belt pumped limiter. Limiter design issues addressed in this paper are (1) poloidal location of the limiter belt, (2) shape of the limiter surface facing the plasma, and (3) whether the belt is pumped from one or both sides. The criteria used for evaluation of limiter configuration features were sensitivity to plasma edge conditions and ease of maintenance and fabrication. The evaluation resulted in the selection of a baseline FED limiter that is located at the bottom of the device and has a flat surface with a single leading edge

  10. 5 CFR 551.702 - Time limits.

    Science.gov (United States)

    2010-01-01

    ... at any time file a complaint under the child labor provisions of the Act or an FLSA claim challenging... claim concerning his or her entitlement to minimum wage or overtime pay for work performed under the Act... limitations is 3 years. In deciding a claim, a determination must be made as to whether the cause or basis of...

  11. Mass limit for the lightest neutralino

    CERN Document Server

    Buskulic, D.; Decamp, D.; Ghez, Philippe; Goy, C.; Lees, J.P.; Lucotte, A.; Minard, M.N.; Nief, J.Y.; Odier, P.; Pietrzyk, B.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I.C.; Pascual, A.; Perlas, J.A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A.O.; Bright-Thomas, P.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R.W.; Frank, M.; Hagelberg, R.; Harvey, John; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Martin, E.B.; Mato, P.; Minten, A.; Miquel, R.; Mir, L.M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.F.; Ranjard, F.; Rensing, P.; Rolandi, Gigi; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I.R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barres, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.M.; Fearnley, T.; Hansen, J.B.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.C.; Rouge, A.; Rumpf, M.; Valassi, A.; Videau, H.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D.E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S.J.; Halley, A.W.; Knowles, I.G.; Lynch, J.G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J.M.; Smith, K.; Teixeira-Dias, P.; Thompson, A.S.; Thomson, F.; Thorn, S.; Turnbull, R.M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Dornan, P.J.; Morawitz, P.; Moutoussi, A.; Nash, J.; Sedgbeer, J.K.; Stacey, A.M.; Williams, M.D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A.P.; Bowdery, C.K.; Colrain, P.; Crawford, G.; Finch, A.J.; Foster, F.; Hughes, G.; Sloan, T.; Whelan, E.P.; Williams, M.I.; Galla, A.; Greene, A.M.; Hoffmann, C.; Jacobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J.J.; Bencheikh, A.M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Tilquin, A.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Bauer, C.; Berlich, R.; Blum, W.; Buescher, Volker; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lutjens, G.; Lutz, G.; Manner, W.; Moser, H.G.; Richter, Robert; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, Richard Dante; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Hocker, Andreas; Jacholkowska, A.; Jacquet, M.; Kim, D.W.; Le Diberder, F.; Lefrancois, J.; Lutz, A.M.; Nikolic, Irina; Park, H.J.; Schune, M.H.; Simion, S.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, Giuseppe; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M.A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P.G.; Walsh, J.; Blair, G.A.; Bryant, L.M.; Cerutti, F.; Chambers, J.T.; Gao, Y.; Green, M.G.; Medcalf, T.; Perrodo, P.; Strong, J.A.; von Wimmersperg-Toeller, J.H.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Haywood, S.; Maley, P.; Norton, P.R.; Thompson, J.C.; Wright, A.E.; Bloch-Devaux, Brigitte; Colas, P.; Emery, S.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S.N.; Dann, J.H.; Johnson, R.P.; Kim, H.Y.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Boswell, R.; Brew, C.A.J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W.M.; Reeve, J.; Thompson, L.F.; Boehrer, Armin; Brandt, S.; Cowan, G.; Grupen, C.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, N.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Putz, J.; Rothberg, J.; Wasserbaech, S.; Armstrong, S.R.; Elmer, P.; Feng, Z.; Ferguson, D.P.S.; Gao, Y.S.; Gonzales, S.; Grahl, J.; Greening, T.C.; Hayes, O.J.; Hu, H.; McNamara, P.A., III; Nachtman, J.M.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Walsh, A.M.; Wu, Sau Lan; Wu, X.; Yamartino, J.M.; Zheng, M.; Zobernig, G.

    1996-01-01

    Indirect limits on the mass of the lightest neutralino are derived from the results of searches for charginos, neutralinos, and sleptons performed with data taken by the ALEPH Collaboration at centre-of-mass energies near the Z peak and at 130 and 136 GeV. Within the context of the Minimal Supersymmetric Standard Model and when $M_{\\tilde\

  12. 40 CFR 35.718 - Award limitation.

    Science.gov (United States)

    2010-07-01

    ... included in the Performance Partnership Grant work plan. Hazardous Waste Management Program Grants (Pub.L... ASSISTANCE Environmental Program Grants for Tribes Toxic Substances Compliance Monitoring (section 28) § 35.718 Award limitation. If the Toxic Substances Compliance Monitoring grant funds are included in a...

  13. Charter Halibut Limited Access Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This limited access system limits the number of charter vessels that may participate in the guided sport fishery for halibut in area 2C and 3A. NMFS issues a charter...

  14. First pump limiter experiments in Tore Supra

    International Nuclear Information System (INIS)

    Chatelier, M.; Bruneau, J.L.; Chappuis, P.; Gil, C.; Guilhem, D.; Lipa, M.; Rodriguez, L.; Vallet, J.C.; Van Houtte, D.; Watkins, J.G.

    1989-01-01

    The thermal load and the particle pumping effects on the outboard pump limiters (OPL), in Tore Supra are analyzed. The investigations are performed for the plasma either in contact with the OPL/ONPL (outboard non pumped limiters) alone or with the OPL and the vertical limiters together. Calorimetric measurements provide estimates of the time-integrated balance of the energy flow at the plasma edge. Radiated and charge exchange energy losses are deduced from the inner vessel calorimetry (R=242cm, a=94cm). Conductive/convective losses on the OPL and vertical (top and bottom) limiters are independently measured, as well as the integrated energy flow on the ergodic divertors. The calorimetric results, the bolometric measurements of the radiated power and the Ohmic power estimates, are indicated. The central line density from interferometric measurement for the two successive shots, with the ONPL and with the OPL, are given

  15. The limits of informed consent.

    Science.gov (United States)

    1975-09-01

    The patient, a 59-year-old man, was referred to a psychiatric hospital with what appeared initially to be the signs and symptoms of mental disorder. In hospital a lesion of the brain was diagnosed and surgery was proposed to relieve the condition. The patient, however, during this and subsequent admissions to hospital, refused operation. His refusal to consent was regarded as valid as he seemed to have good insight into his condition. Finally, under section 26 of the Mental Health Act, he was treated surgically. Unfortunately the patient died six weeks later of intracranial haemorrhage. Three comments are made on this case - two by psychiatrists, Dr K Davison and Dr Ashley Robin, the other by a professor of Christian ethics, Professor F C Blackie. Both psychiatrists argue that when a patient's mind is affected by mental or organic illness to the degree that 'he cannot bring a rational and conscious mind' to the question of his treatment then the doctor, in consultation with the relatives, making clear to them the likely course of events if an operation is not performed, must take whatever is the proper course of action, in this case surgery. In this view, such an operation performed immediately the diagnosis was confirmed might not have been so complicated. Professor Blackie, commending 'the attempt to regard the patient as a responsible human being' with a 'moral right to be consulted on all aspects of treatment', questions in this patient the limits to which the appeal to reason was carried. He concludes that 'in this situation the advice and consent of the family must weigh more heavily than the statements of the patient'.

  16. The limits on trypanosomatid morphological diversity.

    Directory of Open Access Journals (Sweden)

    Richard John Wheeler

    Full Text Available Cell shape is one, often overlooked, way in which protozoan parasites have adapted to a variety of host and vector environments and directional transmissions between these environments. Consequently, different parasite life cycle stages have characteristic morphologies. Trypanosomatid parasites are an excellent example of this in which large morphological variations between species and life cycle stage occur, despite sharing well-conserved cytoskeletal and membranous structures. Here, using previously published reports in the literature of the morphology of 248 isolates of trypanosomatid species from different hosts, we perform a meta-analysis of the occurrence and limits on morphological diversity of different classes of trypanosomatid morphology (trypomastigote, promastigote, etc. in the vertebrate bloodstream and invertebrate gut environments. We identified several limits on cell body length, cell body width and flagellum length diversity which can be interpreted as biomechanical limits on the capacity of the cell to attain particular dimensions. These limits differed for morphologies with and without a laterally attached flagellum which we suggest represent two morphological superclasses, the 'juxtaform' and 'liberform' superclasses. Further limits were identified consistent with a selective pressure from the mechanical properties of the vertebrate bloodstream environment; trypanosomatid size showed limits relative to host erythrocyte dimensions. This is the first comprehensive analysis of the limits of morphological diversity in any protozoan parasite, revealing the morphogenetic constraints and extrinsic selection pressures associated with the full diversity of trypanosomatid morphology.

  17. Performing ERP, Performing Society

    DEFF Research Database (Denmark)

    Koch, Christian

    suites, during the third period of ERP change. Other, more basic technology developments are more important than new software applications. A biography of a community consists of technical, organizational, financial and marketing changes and occasions. Research limitations/implications: A community...

  18. Pure Phase Solubility Limits: LANL

    International Nuclear Information System (INIS)

    C. Stockman

    2001-01-01

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO 2 partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility products

  19. Pure Phase Solubility Limits: LANL

    Energy Technology Data Exchange (ETDEWEB)

    C. Stockman

    2001-01-26

    The natural and engineered system at Yucca Mountain (YM) defines the site-specific conditions under which one must determine to what extent the engineered and the natural geochemical barriers will prevent the release of radioactive material from the repository. Most important mechanisms for retention or enhancement of radionuclide transport include precipitation or co-precipitation of radionuclide-bearing solid phases (solubility limits), complexation in solution, sorption onto surfaces, colloid formation, and diffusion. There may be many scenarios that could affect the near-field environment, creating chemical conditions more aggressive than the conditions presented by the unperturbed system (such as pH changes beyond the range of 6 to 9 or significant changes in the ionic strength of infiltrated waters). For an extended period of time, the near-field water composition may be quite different and more extreme in pH, ionic strength, and CO{sub 2} partial pressure (or carbonate concentration) than waters at some distance from the repository. Reducing conditions, high pH (up to 11), and low carbonate concentration may be present in the near-field after reaction of infiltrating groundwater with engineered barrier systems, such as cementitious materials. In the far-field, conditions are controlled by the rock-mass buffer providing a near-neutral, oxidizing, low-ionic-strength environment that controls radionuclide solubility limits and sorption capacities. There is the need for characterization of variable chemical conditions that affect solubility, speciation, and sorption reactions. Modeling of the groundwater chemistry is required and leads to an understanding of solubility and speciation of the important radionuclides. Because experimental studies cannot be performed under the numerous potential chemical conditions, solubility limitations must rely on geochemical modeling of the radionuclide's chemistry. Fundamental thermodynamic properties, such as solubility

  20. Shear wall ultimate drift limits

    International Nuclear Information System (INIS)

    Duffey, T.A.; Goldman, A.; Farrar, C.R.

    1994-04-01

    Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated

  1. Microdosimetric basis for exposure limits

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Braby, L.A.

    1986-10-01

    The new organ-weighted effective dose equivalents should provide a much more accurate estimation of the degree of hazard for a worker's exposure to ionizing radiations. The method involves the microdosimetric concept of lineal energy to help establish exposure limits and will provide a unified system applicable to all types of ionizing radiation. Rather than being only calculated values, the effective dose equivalents and quality factors will be experimentally measured using tissue equivalent proportional counters. The measurement may be difficult to perform at various depths in an anthropomorphic phantom. Operational health physicists will be concerned about the lack of survey instruments and personnel dosimeters that measure lineal energy distributions. Their possible objections may be mitigated by the commercial introduction of instruments based upon tissue equivalent proportional counters or related devices containing inexpensive microprocessors. The many potential benefits include providing a uniform method for implementing the proposed increases in quality factors for neutrons and photons, providing a more unified approach for combining external and internal exposures, and potentially resolving questions about dosimeter placement and dose assessment for nonuniform exposures to mixed radiations. 16 refs., 3 figs

  2. On the Sen limit squared

    OpenAIRE

    Fullwood, James; Wang, Dongxu

    2018-01-01

    We introduce a class of F-theory vacua whose smooth elliptic fibers admit a vanishing $j$-invariant, and construct a weak coupling limit associated with such vacua which we view as the `square' of the Sen limit. We find that while Sen's limit is naturally viewed as an orientifold theory, the universal tadpole relation which equates the D3 charge between the associated F-theory compactification and the limit we construct suggests that perhaps the limiting theory is in fact an oriented theory c...

  3. Performance prediction and flow-field analysis of rotors in hover using a coupled Euler/boundary layer method; Previsions des performances et de l`ecoulement pour des rotors en vol stationnaire par une methode couplee Euler/couche limite

    Energy Technology Data Exchange (ETDEWEB)

    Beaumier, P. [ONERA, 92 - Chatillon (France); Castellin, C.; Arnaud, G. [Eurocopter France, 13 - Marignane (France)

    1998-12-31

    The performance prediction of helicopter in hover is of key importance for manufacturers because hover is a design configuration for the definition of a rotor-craft. A lot of efforts have been made for more than 10 years all over the world in order to develop and validate numerical methods based on CFD. An Euler method (WAVES) developed by ONERA and coupled with a boundary layer code (MI3DI) is presented, validated and applied to compute the total performance of rotors with different tip shapes. A new boundary condition for the Euler code has been tested and enables better calculation by eliminating `numerical` recirculation. The code has demonstrated its ability to rank two rotors with different planforms in good agreement with experiment. Under industrial requirements new grid strategies have been studied and should allow to reduce CPU time consumption. It is shown that WAVES/MI3DI can be efficiently used in the aerodynamic design process of a new rotor. (authors) 7 refs.

  4. Material limitations on the detection limit in refractometry.

    Science.gov (United States)

    Skafte-Pedersen, Peder; Nunes, Pedro S; Xiao, Sanshui; Mortensen, Niels Asger

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  5. Material Limitations on the Detection Limit in Refractometry

    Directory of Open Access Journals (Sweden)

    Niels Asger Mortensen

    2009-10-01

    Full Text Available We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  6. Material Limitations on the Detection Limit in Refractometry

    OpenAIRE

    Skafte-Pedersen, Peder; Nunes, Pedro S.; Xiao, Sanshui; Mortensen, Niels Asger

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a...

  7. Thermodynamic limit for coherence-limited solar power conversion

    Science.gov (United States)

    Mashaal, Heylal; Gordon, Jeffrey M.

    2014-09-01

    The spatial coherence of solar beam radiation is a key constraint in solar rectenna conversion. Here, we present a derivation of the thermodynamic limit for coherence-limited solar power conversion - an expansion of Landsberg's elegant basic bound, originally limited to incoherent converters at maximum flux concentration. First, we generalize Landsberg's work to arbitrary concentration and angular confinement. Then we derive how the values are further lowered for coherence-limited converters. The results do not depend on a particular conversion strategy. As such, they pertain to systems that span geometric to physical optics, as well as classical to quantum physics. Our findings indicate promising potential for solar rectenna conversion.

  8. Embracing the quantum limit in silicon computing.

    Science.gov (United States)

    Morton, John J L; McCamey, Dane R; Eriksson, Mark A; Lyon, Stephen A

    2011-11-16

    Quantum computers hold the promise of massive performance enhancements across a range of applications, from cryptography and databases to revolutionary scientific simulation tools. Such computers would make use of the same quantum mechanical phenomena that pose limitations on the continued shrinking of conventional information processing devices. Many of the key requirements for quantum computing differ markedly from those of conventional computers. However, silicon, which plays a central part in conventional information processing, has many properties that make it a superb platform around which to build a quantum computer. © 2011 Macmillan Publishers Limited. All rights reserved

  9. Pumped-limiter study for Alcator DCT

    International Nuclear Information System (INIS)

    Brooks, J.N.; Mattas, R.F.; Cha, Y.S.; Hassanein, A.M.; Majumdar, S.

    1983-06-01

    A study was performed for a pumped-limiter design for the proposed Alcator DCT device. The study focused on reactor-relevant issues. The main issues examined were configuration, surface erosion, thermal hydraulics, and the choice of structural and surface materials. A bottom, flat limiter, with a copper-alloy substrate, seems to be a reasonable design and should provide an opportunity to test high power and particle loadings. Carbon is recommended as a surface material if acceptable redeposition properties can be demonstrated

  10. Pumped-limiter study for Alcator DCT

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, J.N.; Mattas, R.F.; Cha, Y.S.; Hassanein, A.M.; Majumdar, S.

    1983-06-01

    A study was performed for a pumped-limiter design for the proposed Alcator DCT device. The study focused on reactor-relevant issues. The main issues examined were configuration, surface erosion, thermal hydraulics, and the choice of structural and surface materials. A bottom, flat limiter, with a copper-alloy substrate, seems to be a reasonable design and should provide an opportunity to test high power and particle loadings. Carbon is recommended as a surface material if acceptable redeposition properties can be demonstrated.

  11. Beam-intensity limitations in linear accelerators

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1981-01-01

    Recent demand for high-intensity beams of various particles has renewed interest in the investigation of beam current and beam quality limits in linear RF and induction accelerators and beam-transport channels. Previous theoretical work is reviewed, and new work on beam matching and stability is outlined. There is a real need for extending the theory to handle the time evolution of beam emittance; some present work toward this goal is described. The role of physical constraints in channel intensity limitation is emphasized. Work on optimizing channel performance, particularly at low particle velocities, has resulted in major technological advances. The opportunities for combining such channels into arrays are discussed. 50 references

  12. Material limitations on the detection limit in refractometry

    DEFF Research Database (Denmark)

    Skafte-Pedersen, Peder; Nunes, Pedro; Xiao, Sanshui

    2009-01-01

    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and...

  13. Further limitations on nuclear testing

    International Nuclear Information System (INIS)

    Brown, P.S.

    1991-11-01

    This document addresses a number of subjects related to further constraints on nuclear testing, briefly discussing each of the following topics: the current political situation, the kinds of steps that might next be taken in test limitations and the impacts of further testing limits, the need for a test ban readiness program, some issues related to verification, and the possibility of confidence building measures as alternative, or near-term, steps to further test limitations

  14. ICRF power limitation relation to density limit in ASDEX

    International Nuclear Information System (INIS)

    Ryter, F.

    1992-01-01

    Launching high ICRF power into ASDEX plasmas required good antenna-plasma coupling. This could be achieved by sufficient electron density in front of the antennas i.e. small antenna-plasma distance (1-2 cm) and moderate to high line-averaged electron density compared to the density window in ASDEX. These are conditions eventually close to the density limit. ICRF heated discharges terminated by plasma disruptions caused by the RF pulse limited the maximum RF power which can be injected into the plasma. The disruptions occurring in these cases have clear phenomenological similarities with those observed in density limit discharges. We show in this paper that the ICRF-power limitation by plasma disruptions in ASDEX was due to reaching the density limit. (orig.)

  15. ICRF power limitation relation to density limit in ASDEX

    International Nuclear Information System (INIS)

    Ryter, F.

    1992-01-01

    Launching high ICRF power into ASDEX plasmas required good antenna-plasma coupling. This could be achieved by sufficient electron density in front of the antennas i.e. small antenna-plasma distance (1-2 cm) and moderate to high line-averaged electron density compared to the density window in ASDEX. These are conditions eventually close to the density limit. ICRF heated discharges terminated by plasma disruptions caused by the RF pulse limited the maximum RF power which can be injected into the plasma. The disruptions occurring in these cases have clear phenomenological similarities with those observed in density limit discharges. We show in this paper that the ICRF-power limitation by plasma disruptions in ASDEX was due to reaching the density limit. (author) 3 refs., 3 figs

  16. Limit cycles in quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Patrick

    2015-04-27

    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  17. Magnetic shielding of a limiter

    International Nuclear Information System (INIS)

    Brevnov, N.N.; Stepanov, S.B.; Khimchenko, L.N.; Matthews, G.F.; Goodal, D.H.J.

    1991-01-01

    Localization of plasma interaction with material surfaces in a separate chamber, from where the escape of impurities is hardly realized, i.e. application of magnetic divertors or pump limiters, is the main technique for reduction of the impurity content in a plasma. In this case, the production of a divertor configuration requires a considerable power consumption and results in a less effective utilization of the magnetic field volume. Utilization of a pump limiter, for example the ICL-type, under tokamak-reactor conditions would result in the extremely high and forbidden local heat loadings onto the limiter surface. Moreover, the magnetically-shielded pump limiter (MSL) was proposed to combine positive properties of the divertor and the pump limiter. The idea of magnetic shielding is to locate the winding with current inside the limiter head so that the field lines of the resultant magnetic field do not intercept the limiter surface. In this case the plasma flows around the limiter leading edges and penetrates into the space under the limiter. The shielding magnetic field can be directed either counter the toroidal field or counter the poloidal one of a tokamak, dependent on the concrete diagram of the device. Such a limiter has a number of advantages: -opportunity to control over the particle and impurity recycling without practical influence upon the plasma column geometry, - perturbation of a plasma column magnetic configuration from the side of such a limiter is less than that from the side of the divertor coils. The main deficiency is the necessity to locate active windings inside the discharge chamber. (author) 5 refs., 3 figs

  18. Force Limited Vibration Test of HESSI Imager

    Science.gov (United States)

    Amato, Deborah; Pankow, David; Thomsen, Knud

    2000-01-01

    The High Energy Solar Spectroscopic Imager (HESSI) is a solar x-ray and gamma-ray observatory scheduled for launch in November 2000. Vibration testing of the HESSI imager flight unit was performed in August 1999. The HESSI imager consists of a composite metering tube, two aluminum trays mounted to the tube on titanium flexure mounts, and nine modulation grids mounted on each tray. The vibration tests were acceleration controlled and force limited, in order to prevent overtesting. The force limited strategy reduced the shaker force and notched the acceleration at resonances. The test set-up, test levels, and results are presented. The development of the force limits is also discussed. The imager successfully survived the vibration testing.

  19. Limited aperture effects on ultrasonic image reconstruction

    International Nuclear Information System (INIS)

    Kogan, V.G.; Rose, J.H.

    1985-01-01

    In the inverse Born approximation the shape of a weak scatterer can be determined from a knowledge of the backscattered ultrasonic amplitude for all directions of incidence and all frequencies. Two questions are considered. First, what information on the scatterer shape is preserved and what is degraded if the scattering data are available only within a limited set of incident directions (limited aperture). This problem is addressed for a spherical weakly scattering uniform flaw. It is shown that the problem of a general uniform ellipsoidal flaw can be reduced to the spherical case by a scale transformation; however, the apertures in these two cases must be related by the same transformation. Second, limited aperture and finite bandwidth Born inversions were performed for strongly scattering flaws (voids and cracks) using numerically generated scattering amplitudes. These inversions were then compared with the weak scattering analytic results, which show many common features

  20. β limit disruptions in the TFTR tokamak

    International Nuclear Information System (INIS)

    Fredrickson, E.D.; McGuire, K.; Janos, A.; Bell, M.; Budny, R.V.; Bush, C.E.; Manickam, J.; Mynick, H.; Nazikian, R.; Taylor, G.

    1994-11-01

    A disruptive β limit (β = plasma pressure/magnetic pressure) is observed in high performance plasmas in TFTR. The MHD character of these disruptions differs substantially from the disruptions in high density plasmas (density limit disruptions) on TFTR. The high β disruptions can occur with less than a milliseconds warning in the form of a fast growing precursor. The precursor appears to be an external kink or internal (m,n)=(1,1) kink strongly coupled through finite β effects and toroidal terms to higher m components. It does not have the open-quote cold bubble close-quote structure found in density limit disruptions. There is also no evidence for a change in the internal inductance, i.e., a major reconnection of the flux, at the time of the thermal quench

  1. Numerical Limit Analysis of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    For more than half a century, limit state analysis based on the extremum principles have been used to assess the load bearing capacity of reinforced concrete structures. Extensi- ve research within the field has lead to several techniques for performing such analysis manually. While these manual...... methods provide engineers with valuable tools for limit sta- te analysis, their application becomes difficult with increased structural complexity. The main challenge is to solve the optimization problem posed by the extremum principles. This thesis is a study of how numerical methods can be used to solve...... limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...

  2. Primary system temperature limits and transient mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Drucker, G.S.; Bost, D.S.

    1978-10-03

    Results of a study to determine the limiting temperature conditions in a large reactor system are presented. The study considers a sodium-cooled breeder reactor system having a loop-type primary system configuration. A temperature range of 930 to 1050/sup 0/F in reactor outlet temperature is covered. Significant findings were that the use of the materials for the 930/sup 0/F reference design, i.e., a core material of 20% cold-worked 316 stainless steel, a primary piping material of 316SS, and a steam generator material of unstabilized 2-1/4 Cr - 1 Mo resulted in limiting conditions in component performance at the higher temperatures. Means to circumvent these limits through the use of alternate materials, mitigation of thermal transients, and/or design changes are presented. The economic incentive to make some materials changes is also presented.

  3. Determination and Interpretation of Characteristic Limits for Radioactivity Measurements: Decision Threshhold, Detection Limit and Limits of the Confidence Interval

    International Nuclear Information System (INIS)

    2017-01-01

    Since 2004, the environment programme of the IAEA has included activities aimed at developing a set of procedures for analytical measurements of radionuclides in food and the environment. Reliable, comparable and fit for purpose results are essential for any analytical measurement. Guidelines and national and international standards for laboratory practices to fulfil quality assurance requirements are extremely important when performing such measurements. The guidelines and standards should be comprehensive, clearly formulated and readily available to both the analyst and the customer. ISO 11929:2010 is the international standard on the determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measuring ionizing radiation. For nuclear analytical laboratories involved in the measurement of radioactivity in food and the environment, robust determination of the characteristic limits of radioanalytical techniques is essential with regard to national and international regulations on permitted levels of radioactivity. However, characteristic limits defined in ISO 11929:2010 are complex, and the correct application of the standard in laboratories requires a full understanding of various concepts. This publication provides additional information to Member States in the understanding of the terminology, definitions and concepts in ISO 11929:2010, thus facilitating its implementation in Member State laboratories.

  4. Tachyons in the Galilean limit

    Energy Technology Data Exchange (ETDEWEB)

    Batlle, Carles [Departament de Matemàtiques and IOC, Universitat Politècnica de Catalunya, EPSEVG,Av. V. Balaguer 1, Vilanova i la Geltrú, E-08808 (Spain); Gomis, Joaquim [Departament de Física Quàntica i Astrofísica and Institut de Ciències del Cosmos (ICCUB),Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028 (Spain); Mezincescu, Luca [Department of Physics, University of Miami,P.O. Box 248046, Coral Gables, FL, 33124 (United States); Townsend, Paul K. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences,University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2017-04-20

    The Souriau massless Galilean particle of “colour” k and spin s is shown to be the Galilean limit of the Souriau tachyon of mass m=ik and spin s. We compare and contrast this result with the Galilean limit of the Nambu-Goto string and Green-Schwarz superstring.

  5. Solubility limits on radionuclide dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Kerrisk, J.F.

    1984-12-31

    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.

  6. Dose limits for ionising radiation

    International Nuclear Information System (INIS)

    Gifford, D.

    1989-01-01

    Dose limits for exposure to ionising radiation are assessed to see if they give sufficient protection both for the occupationally exposed and for the general public. It is concluded that current limits give a level of safety that satisfies the necessary criteria in the light of present knowledge and further reductions would be unlikely to improve standards of safety. (author)

  7. FUEL CASK IMPACT LIMITER VULNERABILITIES

    International Nuclear Information System (INIS)

    Leduc, D.; England, J.; Rothermel, R.

    2009-01-01

    Cylindrical fuel casks often have impact limiters surrounding just the ends of the cask shaft in a typical 'dumbbell' arrangement. The primary purpose of these impact limiters is to absorb energy to reduce loads on the cask structure during impacts associated with a severe accident. Impact limiters are also credited in many packages with protecting closure seals and maintaining lower peak temperatures during fire events. For this credit to be taken in safety analyses, the impact limiter attachment system must be shown to retain the impact limiter following Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC) impacts. Large casks are often certified by analysis only because of the costs associated with testing. Therefore, some cask impact limiter attachment systems have not been tested in real impacts. A recent structural analysis of the T-3 Spent Fuel Containment Cask found problems with the design of the impact limiter attachment system. Assumptions in the original Safety Analysis for Packaging (SARP) concerning the loading in the attachment bolts were found to be inaccurate in certain drop orientations. This paper documents the lessons learned and their applicability to impact limiter attachment system designs

  8. Beam-limiting and radiation-limiting interlocks

    International Nuclear Information System (INIS)

    Macek, R.J.

    1996-01-01

    This paper reviews several aspects of beam-limiting and radiation- limiting interlocks used for personnel protection at high-intensity accelerators. It is based heavily on the experience at the Los Alamos Neutron Science Center (LANSCE) where instrumentation-based protection is used extensively. Topics include the need for ''active'' protection systems, system requirements, design criteria, and means of achieving and assessing acceptable reliability. The experience with several specific devices (ion chamber-based beam loss interlock, beam current limiter interlock, and neutron radiation interlock) designed and/or deployed to these requirements and criteria is evaluated

  9. Limits to magnetic resonance microscopy

    International Nuclear Information System (INIS)

    Glover, Paul; Mansfield, Peter

    2002-01-01

    The last quarter of the twentieth century saw the development of magnetic resonance imaging (MRI) grow from a laboratory demonstration to a multi-billion dollar worldwide industry. There is a clinical body scanner in almost every hospital of the developed nations. The field of magnetic resonance microscopy (MRM), after mostly being abandoned by researchers in the first decade of MRI, has become an established branch of the science. This paper reviews the development of MRM over the last decade with an emphasis on the current state of the art. The fundamental principles of imaging and signal detection are examined to determine the physical principles which limit the available resolution. The limits are discussed with reference to liquid, solid and gas phase microscopy. In each area, the novel approaches employed by researchers to push back the limits of resolution are discussed. Although the limits to resolution are well known, the developments and applications of MRM have not reached their limit. (author)

  10. LANSCE Beam Current Limiter (XL)

    International Nuclear Information System (INIS)

    Gallegos, F.R.; Hall, M.J.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) is an engineered safety system that provides personnel protection from prompt radiation due to accelerated proton beams. The Beam Current Limiter (XL), as an active component of the RSS, limits the maximum average current in a beamline, thus the current available for a beam spill accident. Exceeding the pre-set limit initiates action by the RSS to mitigate the hazard (insertion of beam stoppers in the low energy beam transport). The beam limiter is an electrically isolated, toroidal transformer and associated electronics. The device was designed to continuously monitor beamline currents independent of any external timing. Fail-safe operation was a prime consideration in its development. Fail-safe operation is defined as functioning as intended (due to redundant circuitry), functioning with a more sensitive fault threshold, or generating a fault condition. This report describes the design philosophy, hardware, implementation, operation, and limitations of the device

  11. On the density limit of Tokamaks

    International Nuclear Information System (INIS)

    Lehnert, B.

    1982-12-01

    Under the conditions of so far performed quasi-steady tokamak experiments near the density limit, the plasma pressure gradient in the outer layers of the plasma body becomes mainly determined by the plasma-neutral gas balance. An earlier analysis of ballooning instabilities driven by this gradient in regions of bad curvature has been extended to deduce an explicit stability criterion which determines the density limit. This criterion is closely related to the empirical Murakami limit. At relevant tokamak data, the deduced limit becomes proportional to J(sub)zR(sup)1/2 where J(sub)z is the average current density and R the major plasma radius. It is further found to be independent of the toroidal magnetic field strength and anomalous transport, as well as to be a slow function of the outer layer temperature and the mass number. The deduced stability criterion is consistent with so far performed experiments. Provided that the present analysis can be extrapolated to a wider range of parameter data and be combined with Alcator scaling, conditions near ignition appear to become realizable in small tokamaks by ohmic heating alone. These conditions can be satisfied at relevant magnetic field strengths and plasma currents, by imposing a high plasma current density. (author)

  12. Shell Canada Limited 1996 annual report

    International Nuclear Information System (INIS)

    1996-01-01

    Shell Canada Resources Limited is one of Canada's largest producers of crude oil, natural gas, natural gas liquids, sulphur and bitumen. This annual report for 1996 presented a summary review of operations and a summary of the Company's audited consolidated financial statements. Overall, the resources business delivered exceptional results in 1996. The oil products and chemicals businesses did not perform as well as expected. This less than satisfactory performance of the oil products and chemicals divisions of the the Company is reflected in the financial returns which, after excluding revenues from asset sales, left operating earnings $ 59 million below those of 1996. tabs., figs

  13. Limiting characteristics of the superconducting fault current limiter applied to the neutral line of conventional transformer

    International Nuclear Information System (INIS)

    Im, I.G.; Choi, H.S.; Jung, B.I.

    2013-01-01

    Highlights: •Fault current limiter was used a high-speed interrupter. •High-speed interrupter was operated to bypass to the current limiter line. •The size of the fault current was limited to about 80% after the fault occurred. •The fault current was limited quickly within a half-cycle after the fault occurred. -- Abstract: The increased electricity demands influenced by the recent industrial development make the electric power distribution system more comprehensive, and the risks are high to cause failures to steady state electric line due to the extended range of fault at the time of fault occurrence. Also, the high performance and the high precision electric appliances that sensitive to switching surge and fault current expose vulnerability of reduced life span and increased fault occurrence ratio. Therefore, this thesis analyzed the fault limiting characteristics by the fault types by applying the superconducting fault current limiter to the neutral line of the transformer in order to reduce the fault currents that flow such high performance appliances. A current transformer (CT) that detects the fault current in the simulated power distribution system, a switching control system that is self-developed and a transformer are used in constructing a circuit. When a fault occurs, the initial fault current is restricted by the superconducting fault current limiter and simultaneously detours the fault current by operating the SCR contact of the switching control system through the detection by CT. This thesis analyzed the limiting characteristics of the superconducting fault current limiter that are applied to the neutral line of the transformer by the fault types

  14. Limiting characteristics of the superconducting fault current limiter applied to the neutral line of conventional transformer

    Energy Technology Data Exchange (ETDEWEB)

    Im, I.G., E-mail: asiligo@gmail.com; Choi, H.S., E-mail: hyosang@chosun.ac.kr; Jung, B.I.

    2013-11-15

    Highlights: •Fault current limiter was used a high-speed interrupter. •High-speed interrupter was operated to bypass to the current limiter line. •The size of the fault current was limited to about 80% after the fault occurred. •The fault current was limited quickly within a half-cycle after the fault occurred. -- Abstract: The increased electricity demands influenced by the recent industrial development make the electric power distribution system more comprehensive, and the risks are high to cause failures to steady state electric line due to the extended range of fault at the time of fault occurrence. Also, the high performance and the high precision electric appliances that sensitive to switching surge and fault current expose vulnerability of reduced life span and increased fault occurrence ratio. Therefore, this thesis analyzed the fault limiting characteristics by the fault types by applying the superconducting fault current limiter to the neutral line of the transformer in order to reduce the fault currents that flow such high performance appliances. A current transformer (CT) that detects the fault current in the simulated power distribution system, a switching control system that is self-developed and a transformer are used in constructing a circuit. When a fault occurs, the initial fault current is restricted by the superconducting fault current limiter and simultaneously detours the fault current by operating the SCR contact of the switching control system through the detection by CT. This thesis analyzed the limiting characteristics of the superconducting fault current limiter that are applied to the neutral line of the transformer by the fault types.

  15. Information Processing and Limited Liability

    OpenAIRE

    Bartosz Mackowiak; Mirko Wiederholt

    2012-01-01

    Decision-makers often face limited liability and thus know that their loss will be bounded. We study how limited liability affects the behavior of an agent who chooses how much information to acquire and process in order to take a good decision. We find that an agent facing limited liability processes less information than an agent with unlimited liability. The informational gap between the two agents is larger in bad times than in good times and when information is more costly to process.

  16. Limited Releases of Krsko NPP

    International Nuclear Information System (INIS)

    Breznik, B.; Kovac, A.

    2001-01-01

    Full text: Krsko Nuclear Power Plant is about 700 MW Pressurised Water Reactor plant located in Slovenia close to the border with Croatia. The authorised limit for the radioactive releases is basically set to 50 μSv effective dose per year to the members of the public. There is also additional limitation of total activities released in a year and concentration. The poster presents the effluents of the year 2000 and evaluated dose referring to the limits and to the natural and other sources of radiation around the plant. (author)

  17. Nuclear Structure at the Limits

    International Nuclear Information System (INIS)

    Nazarewicz, W.

    1998-01-01

    One of the frontiers of todays nuclear science is the journey to the limits of atomic charge and nuclear mass, of neutron-to-proton ratio, and of angular momentum. The tour to the limits is not only a quest for new, exciting phenomena, but the new data are expected, as well, to bring qualitatively new information about the fundamental properties of the nucleonic many-body system, the nature of the nuclear interaction, and nucleonic correlations at various energy-distance scales. In this series of lectures, current developments in nuclear structure at the limits are discussed from a theoretical perspective, mainly concentrating on medium-mass and heavy nuclei

  18. Understanding protocol performance: impact of test performance.

    Science.gov (United States)

    Turner, Robert G

    2013-01-01

    This is the second of two articles that examine the factors that determine protocol performance. The objective of these articles is to provide a general understanding of protocol performance that can be used to estimate performance, establish limits on performance, decide if a protocol is justified, and ultimately select a protocol. The first article was concerned with protocol criterion and test correlation. It demonstrated the advantages and disadvantages of different criterion when all tests had the same performance. It also examined the impact of increasing test correlation on protocol performance and the characteristics of the different criteria. To examine the impact on protocol performance when individual tests in a protocol have different performance. This is evaluated for different criteria and test correlations. The results of the two articles are combined and summarized. A mathematical model is used to calculate protocol performance for different protocol criteria and test correlations when there are small to large variations in the performance of individual tests in the protocol. The performance of the individual tests that make up a protocol has a significant impact on the performance of the protocol. As expected, the better the performance of the individual tests, the better the performance of the protocol. Many of the characteristics of the different criteria are relatively independent of the variation in the performance of the individual tests. However, increasing test variation degrades some criteria advantages and causes a new disadvantage to appear. This negative impact increases as test variation increases and as more tests are added to the protocol. Best protocol performance is obtained when individual tests are uncorrelated and have the same performance. In general, the greater the variation in the performance of tests in the protocol, the more detrimental this variation is to protocol performance. Since this negative impact is increased as

  19. Superconducting dc fault current limiter

    International Nuclear Information System (INIS)

    Cointe, Y.

    2007-12-01

    Within the framework of the electric power market liberalization, DC networks have many interests compared to alternative ones, but their protections need to use new systems. Superconducting fault current limiters enable by an overstepping of the critical current to limit the fault current to a preset value, lower than the theoretical short-circuit current. For these applications, coated conductors offer excellent opportunities. We worked on the implementation of these materials and built a test bench. We carried out limiting experiments to estimate the quench homogeneity at various short-circuit parameters. An important point is the temperature measurement by deposited sensors on the ribbon, results are in good correlation with the theoretical models. Improved quench behaviours for temperatures close to the critical temperature have been confirmed. Our results enable to better understand the limitation mechanisms of coated conductors. (author)

  20. Guidelines for setting speed limits

    CSIR Research Space (South Africa)

    Wium, DJW

    1986-02-01

    Full Text Available , parking and loading manoeuvres, access to bounding properties, intersections, width of road without central median and clear roadside area. The method should result in greater uniformity in speed limits for similar circumstances as set by different...

  1. The Limits to Giving Back

    Directory of Open Access Journals (Sweden)

    Jade S. Sasser

    2014-07-01

    Full Text Available In this thematic section, authors consider the limitations on giving back that they faced in field research, or saw others face. For some authors, their attempts at giving back were severely limited by the scope of their projects, or their understandings of local cultures or histories. For others, very specific circumstances and historical interventions of foreigners in certain places can limit how and to what extent a researcher is able to have a reciprocal relationship with the participating community. Some authors, by virtue of their lesser positions of power relative to those that they were studying, simply decided not to give back to those communities. In each article it becomes apparent that how and in what ways people give back is unique (and limited both to their personal values and the contexts in which they do research.

  2. Multifamily Tax Subsidy Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — Multifamily Tax Subsidy Projects (MTSP) Income Limits were developed to meet the requirements established by the Housing and Economic Recovery Act of 2008 (Public...

  3. Time Limits : Effects on Recall

    OpenAIRE

    Hirano, Kinue

    2000-01-01

    This study investigates the effects of differing time limits and the level of language proficiency on the written recalls of 66 Japanese EFL undergraduates. Results showed that different time limits affected total recall, but not main ideas recalled. Regardless of proficiency level, the 20-minute group (Group 2) recalled a greater number of idea units than the 8-minute group (Group 1). However, no significant difference was found between Groups 1 and 2 regarding the recall of main ideas, alth...

  4. Limits on the photon mass

    International Nuclear Information System (INIS)

    Vasseur, G.

    1996-03-01

    Is the photon mass strictly null as it is told in quantum electrodynamics. In fact, a coherent theory can be build with a massive photon. Experiences have been regularly led to try to make obvious an eventual non null photon mass. Superior limits more and more strict have been found. Here is given a general survey of the consequences of a non null photon mass, different methods to measure it and the achieved limits. (author). 30 refs., 1 fig

  5. Limited Memory, Categorization, and Competition

    OpenAIRE

    Yuxin Chen; Ganesh Iyer; Amit Pazgal

    2010-01-01

    This paper investigates the effects of a limited consumer memory on the price competition between firms. It studies a specific aspect of memory--namely, the categorization of available price information that the consumers may need to recall for decision making. This paper analyzes competition between firms in a market with uninformed consumers who do not compare prices, informed consumers who compare prices but with limited memory, and informed consumers who have perfect memory. Consumers, aw...

  6. Major Limitations of Satellite images

    OpenAIRE

    Al-Wassai, Firouz A.; Kalyankar, N. V.

    2013-01-01

    Remote sensing has proven to be a powerful tool for the monitoring of the Earth surface to improve our perception of our surroundings has led to unprecedented developments in sensor and information technologies. However, technologies for effective use of the data and for extracting useful information from the data of Remote sensing are still very limited since no single sensor combines the optimal spectral, spatial and temporal resolution. This paper briefly reviews the limitations of satelli...

  7. The JET belt limiter tiles

    International Nuclear Information System (INIS)

    Deksnis, E.

    1988-09-01

    The belt limiter system, comprising two full toroidal rings of limiter tiles, was installed in JET in 1987. In consists of water-cooled fins with the limiter material in form of tile inbetween. The tiles are designed to absorb heat fluxes during irradiation without the surface temperature exceeding 2000 0 C and to radiate this heat between pulses to the water cooled sink whose temperature is lower than that of the vacuum vessel. An important feature of the design is to maximise the area of the radiating surface facing the water cooled fin. This leads to a tile depth much greater than the width of the tile facing the heat flux. Limiter tiles intercept particles flowing out of the plasma through the area between the two belt limiter rings and through remaining surface area of the plasma column. Power deposition to a limiter tile depends strongly on the shape of the plasma, the edge plasma properties as well as on the surface profile of the tiles. This paper will discuss the methodology that was followed in producing an optimized surface profile of the tiles. This shaped profile has the feature that the resulting power deposition profile is roughly similar for a wide range of plasma parameters. (author)

  8. Passive fault current limiting device

    Science.gov (United States)

    Evans, Daniel J.; Cha, Yung S.

    1999-01-01

    A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment.

  9. Power limit and quality limit of natural circulation reactor

    International Nuclear Information System (INIS)

    Zhao Guochang; Ma Changwen

    1997-01-01

    The circulation characteristics of natural circulation reactor in boiling regime are researched. It is found that, the circulation mass flow rate and the power have a peak value at a mass quality respectively. Therefore, the natural circulation reactor has a power limit under certain technological condition. It can not be increased steadily by continually increasing the mass quality. Corresponding to this, the mass quality of natural circulation reactor has a reasonable limit. The relations between the maximum power and the reactor parameters, such as the resistance coefficient, the working pressure and so on, are analyzed. It is pointed out that the power limit of natural circulation reactor is about 1000 MW at present technological condition. Taking the above result and low quality stability experimental result into account, the authors recommend that the reasonable mass quality of natural circulation reactor working in boiling regime is from 2% to 3% under the researched working pressure

  10. 40 CFR 401.12 - Law authorizing establishment of effluent limitations guidelines for existing sources, standards...

    Science.gov (United States)

    2010-07-01

    ... effluent limitations guidelines for existing sources, standards of performance for new sources and... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GENERAL PROVISIONS § 401.12 Law authorizing establishment of effluent limitations guidelines for existing sources, standards of performance...

  11. Time-limited optimal dynamics beyond the Quantum Speed Limit

    DEFF Research Database (Denmark)

    Gajdacz, Miroslav; Das, Kunal K.; Arlt, Jan

    2015-01-01

    The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed has to be paid with a loss of fidelity. Here we quantify the trade-off between the fidelity and the duration in a system driven......-off expressed in terms of the direct Hilbert velocity provides a robust prediction of the quantum speed limit and allows to adapt the control optimization such that it yields a predefined fidelity. The results are verified numerically in a multilevel system with a constrained Hamiltonian, and a classification...

  12. Hydrodynamic Limit of Multiple SLE

    Science.gov (United States)

    Hotta, Ikkei; Katori, Makoto

    2018-04-01

    Recently del Monaco and Schleißinger addressed an interesting problem whether one can take the limit of multiple Schramm-Loewner evolution (SLE) as the number of slits N goes to infinity. When the N slits grow from points on the real line R in a simultaneous way and go to infinity within the upper half plane H, an ordinary differential equation describing time evolution of the conformal map g_t(z) was derived in the N → ∞ limit, which is coupled with a complex Burgers equation in the inviscid limit. It is well known that the complex Burgers equation governs the hydrodynamic limit of the Dyson model defined on R studied in random matrix theory, and when all particles start from the origin, the solution of this Burgers equation is given by the Stieltjes transformation of the measure which follows a time-dependent version of Wigner's semicircle law. In the present paper, first we study the hydrodynamic limit of the multiple SLE in the case that all slits start from the origin. We show that the time-dependent version of Wigner's semicircle law determines the time evolution of the SLE hull, K_t \\subset H\\cup R, in this hydrodynamic limit. Next we consider the situation such that a half number of the slits start from a>0 and another half of slits start from -a exact solutions, we will discuss the universal long-term behavior of the multiple SLE and its hull K_t in the hydrodynamic limit.

  13. Fundamental limits of positron emission mammography

    International Nuclear Information System (INIS)

    Moses, William W.; Qi, Jinyi

    2001-01-01

    We explore the causes of performance limitation in positron emission mammography cameras. We compare two basic camera geometries containing the same volume of 511 keV photon detectors, one with a parallel plane geometry and another with a rectangular geometry. We find that both geometries have similar performance for the phantom imaged (in Monte Carlo simulation), even though the solid angle coverage of the rectangular camera is about 50 percent higher than the parallel plane camera. The reconstruction algorithm used significantly affects the resulting image; iterative methods significantly outperform the commonly used focal plane tomography. Finally, the characteristics of the tumor itself, specifically the absolute amount of radiotracer taken up by the tumor, will significantly affect the imaging performance

  14. Generalized Geometric Quantum Speed Limits

    Directory of Open Access Journals (Sweden)

    Diego Paiva Pires

    2016-06-01

    Full Text Available The attempt to gain a theoretical understanding of the concept of time in quantum mechanics has triggered significant progress towards the search for faster and more efficient quantum technologies. One of such advances consists in the interpretation of the time-energy uncertainty relations as lower bounds for the minimal evolution time between two distinguishable states of a quantum system, also known as quantum speed limits. We investigate how the nonuniqueness of a bona fide measure of distinguishability defined on the quantum-state space affects the quantum speed limits and can be exploited in order to derive improved bounds. Specifically, we establish an infinite family of quantum speed limits valid for unitary and nonunitary evolutions, based on an elegant information geometric formalism. Our work unifies and generalizes existing results on quantum speed limits and provides instances of novel bounds that are tighter than any established one based on the conventional quantum Fisher information. We illustrate our findings with relevant examples, demonstrating the importance of choosing different information metrics for open system dynamics, as well as clarifying the roles of classical populations versus quantum coherences, in the determination and saturation of the speed limits. Our results can find applications in the optimization and control of quantum technologies such as quantum computation and metrology, and might provide new insights in fundamental investigations of quantum thermodynamics.

  15. The estimation of derived limits

    International Nuclear Information System (INIS)

    Harrison, N.T.; Bryant, P.M.; Clarke, R.H.; Morley, F.

    1979-08-01

    In practical radiation protection, it is often necessary to calculate limits of intake of radionuclides associated with various quantities; such limits are needed, for example, to assess the adequacy of the control of environmental contamination. In publication 26 of the International Commission on Radiological Protection (ICRP), these limits, when related to the basic limits of dose-equivalent by a defined model, are referred to as Derived Limits (DLs). In the present report the principles to be adopted by the Board in calculating DLs to be recommended for general application within the United Kingdom are outlined. DLs will be recommended for a wide range of radionuclides and for circumstances relevant to the workplace, and, more frequently, the general environment. The latter will include DLs in foodstuffs and associated environmental materials, such as soil and grass, and DLs for discharges from stacks. DLs will be related to dose equivalents for workers or members of the public for stochastic or non-stochastic effects as appropriate. Consideration will be given to relevant data on radiosensitivity, metabolism and dosimetry for children and to the physicochemical forms of radionuclides. (author)

  16. Penrose limits and RG flows

    International Nuclear Information System (INIS)

    Gimon, Eric G.; Sonnenschein, Jacob; Pando Zayas, Leopoldo A.

    2002-01-01

    The Penrose-Gueven limit simplifies a given supergravity solution into a pp-wave background. Aiming at clarifying its relation to renormalization group flow we study the Penrose-Guven limit of supergravity backgrounds that are dual to non-conformal gauge theories. The resulting backgrounds fall in a class simple enough that the quantum particle is exactly solvable. We propose a map between the effective time-dependent quantum mechanical problem and the RG flow in the gauge theory. As a testing ground we consider explicitly two Penrose limits of the infrared fixed point of the Pilch-Warner solution. We analyze the corresponding gauge theory picture and write down the operators which are the duals of the low lying string states. We also address RG flows of a different nature by considering the Penrose-Gueven limit of a stack of N D p branes. We note that in the far IR (for p<3)the limit generically has negative mass-squared. This phenomenon signals, in the world sheet picture, the necessity to transform to another description. In this regard, we consider explicitly the cases of M2 from D2 and F1 from D1. (author)

  17. Comparison among tomographic reconstruction with limited data

    International Nuclear Information System (INIS)

    Oliveira, Eric F.; Dantas, Carlos C.; Vasconcelos, Daniel A.A.; Cadiz, Luis F.; Melo, Silvio B.

    2011-01-01

    Nowadays there is a continuing interest in applying computed tomography (CT) techniques in non-destructive testing and inspection of many industrial products. These applications of CT usually require a differentiated analysis when there are strong limitations in acquiring a sufficiently large amount of projection data. The use of a low number of tomographic data normally degrades the quality of the reconstructed image, highlighting the formation of artifacts and noise. This work investigates the reconstruction methods most commonly used (FBP, ART, SIRT, MART, SMART) and shows the performance of each one in this limited scenario. For this purpose, all methods were implemented and tested with a phantom of uniform density with well-known distribution, with measures of transmission of gamma radiation in a first generation CT scanner. The phantom is a concentric stainless steel tube coupled with a half - cylinder of aluminum. The measurements were made with an highest root mean square error, with the formation of visible artifacts. The artifacts are diminished but still visible in the ART and SIRT techniques, and the best performance was observed with the techniques MART and SMART. The technical superiority of these multiplicative methods is clearly seen in the reconstructed image quality, endorsing their application to situations of limited input data. (author)

  18. At the limit of polychromatic microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Ice, Gene E., E-mail: IceGE@ornl.gov [MST Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States); Pang, Judy W.L.; Larson, Bennett C.; Budai, John D.; Tischler, Jonathan Z. [MST Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States); Choi, Jae-Young [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Liu Wenjun; Liu Chian; Assoufid, Lahsen; Shu Deming; Khounsary, Ali [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2009-10-25

    With a high-energy 3rd generation source like the Advanced Photon Source (APS), it is possible to push the performance of polychromatic microdiffraction far beyond current levels and to approach the intrinsic limit of the technique based on sample damage and the diffraction limit of X-rays. We describe ongoing efforts to improve the spatial, temporal and momentum transfer resolution of polychromatic microdiffraction on beamline 34-ID-E at the APS. The goal of this effort is to provide high-resolution images of 3D crystal structures over sufficient volumes and with sufficient detail to clarify the underlying physics of inhomogeneous structure and evolution on mesoscopic length scales. The performance of a high-speed amorphous Si area detector system and the ongoing development of advanced focusing optics will be described and discussed in light of the ultimate limits set by the physics of X-rays and materials, and in light of opportunities to field specialized insertion devices and optics for polychromatic microdiffraction.

  19. The capacity limitations of orientation summary statistics

    Science.gov (United States)

    Attarha, Mouna; Moore, Cathleen M.

    2015-01-01

    The simultaneous–sequential method was used to test the processing capacity of establishing mean orientation summaries. Four clusters of oriented Gabor patches were presented in the peripheral visual field. One of the clusters had a mean orientation that was tilted either left or right while the mean orientations of the other three clusters were roughly vertical. All four clusters were presented at the same time in the simultaneous condition whereas the clusters appeared in temporal subsets of two in the sequential condition. Performance was lower when the means of all four clusters had to be processed concurrently than when only two had to be processed in the same amount of time. The advantage for establishing fewer summaries at a given time indicates that the processing of mean orientation engages limited-capacity processes (Experiment 1). This limitation cannot be attributed to crowding, low target-distractor discriminability, or a limited-capacity comparison process (Experiments 2 and 3). In contrast to the limitations of establishing multiple summary representations, establishing a single summary representation unfolds without interference (Experiment 4). When interpreted in the context of recent work on the capacity of summary statistics, these findings encourage reevaluation of the view that early visual perception consists of summary statistic representations that unfold independently across multiple areas of the visual field. PMID:25810160

  20. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  1. Practical roadmap and limits to nanostructured photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lunt, Richard R. [Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Osedach, Timothy P. [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Brown, Patrick R. [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Rowehl, Jill A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bulovic, Vladimir [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-12-22

    The significant research interest in the engineering of photovoltaic (PV) structures at the nanoscale is directed toward enabling reductions in PV module fabrication and installation costs as well as improving cell power conversion efficiency (PCE). With the emergence of a multitude of nanostructured photovoltaic (nano-PV) device architectures, the question has arisen of where both the practical and the fundamental limits of performance reside in these new systems. Here, the former is addressed a posteriori. The specific challenges associated with improving the electrical power conversion efficiency of various nano-PV technologies are discussed and several approaches to reduce their thermal losses beyond the single bandgap limit are reviewed. Critical considerations related to the module lifetime and cost that are unique to nano-PV architectures are also addressed. The analysis suggests that a practical single-junction laboratory power conversion efficiency limit of 17% and a two-cell tandem power conversion efficiency limit of 24% are possible for nano-PVs, which, when combined with operating lifetimes of 10 to 15 years, could position them as a transformational technology for solar energy markets. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Derived limits for surface contamination

    CERN Document Server

    Wrixon, A D; Linsley, G S; White, D F

    1979-01-01

    Derived limits (DLs) for surface contamination were first established for use in the nuclear energy industry where a wide variety of radionuclides is encountered. They were later used in factories, hospitals, and universities, where the radionuclides used are normally fewer in number, either known or readily identifiable, and often of low toxicity. In these situations the current limits are frequently over-restrictive. This report describes a reassessment of the values in the light of more recent information on the possible pathways of exposure and the dose equivalent limits given in ICRP Publication 26. The reassessment is prompted also by the introduction of SI units. The results of the reassessment are used to produce a classification of DLs for all radionuclides for active and inactive area surfaces and for skin.

  3. Magnetic limiter for thermonuclear device

    International Nuclear Information System (INIS)

    Shimizu, Masatsugu; Nakamura, Hiroo; Takatsu, Hideyuki; Minato, Akihiko; Fukushima, Yutaka.

    1979-01-01

    Purpose: To decrease X-ray irradiation to coils by constituting magnetic limiters as a laminated structure of a carbon outer layer contacting to plasma and an inner molybdenum layer to thereby reduce braking radiation and secondary X-ray generation. Constitution: Magnetic limiters having a molybdenum substrate laminated with a carbon coating on the front surface is provided to a plasma-confining vacuum container. Fast electrons generated from plasma collide against the magnetic limiter and they are stopped by the carbon layer for suppressing the braking radiation, whereby the braking radiation is ended and the X-rays are decayed by the molybdenum layer. This can decrease the amount of X-rays irradiated on the coil. (Kawakami, Y.)

  4. Density limit in JT-60

    International Nuclear Information System (INIS)

    Kamada, Yutaka; Hosogane, Nobuyuki; Hirayama, Toshio; Tsunematsu, Toshihide

    1990-05-01

    This report studies mainly the density limit for a series of gas- and pellet-fuelled limiter discharges in JT-60. With the pellet injection into high-current/low-q (q(a)=2.3∼2.5) discharges, the Murakami factor reaches up to 10∼13 x 10 19 m -2 T -1 . The values are about factors of 1.5∼2.0 higher than those for usual gas-fuelled discharges. The pellet injected discharges have high central density, whereas the electron density in the outer region (a/2 abs and n e 2 (r=50 cm) x Z eff (r=50 cm). (author)

  5. The limits to solar thermal electricity

    International Nuclear Information System (INIS)

    Trainer, Ted

    2014-01-01

    The potential and limits of solar thermal power systems depend primarily on their capacity to meet electricity demand in mid-winter, and the associated cost, storage and other implications. Evidence on output and costs is analysed. Most attention is given to central receivers. Problems of low radiation levels, embodied energy costs, variability and storage are discussed and are found to set significant difficulties for large scale solar thermal supply in less than ideal latitudes and seasons. It is concluded that for solar thermal systems to meet a large fraction of anticipated global electricity demand in winter would involve prohibitive capital costs. - Highlights: • Output and capital cost data for various solar thermal technologies is examined. • Special attention is given to performance in winter. • Attention is also given to the effect of solar intermittency. • Implications for storage are considered. • It is concluded that there are significant limits to solar thermal power

  6. Ensuring the validity of calculated subcritical limits

    International Nuclear Information System (INIS)

    Clark, H.K.

    1977-01-01

    The care taken at the Savannah River Laboratory and Plant to ensure the validity of calculated subcritical limits is described. Close attention is given to ANSI N16.1-1975, ''Validation of Calculational Methods for Nuclear Criticality Safety.'' The computer codes used for criticality safety computations, which are listed and are briefly described, have been placed in the SRL JOSHUA system to facilitate calculation and to reduce input errors. A driver module, KOKO, simplifies and standardizes input and links the codes together in various ways. For any criticality safety evaluation, correlations of the calculational methods are made with experiment to establish bias. Occasionally subcritical experiments are performed expressly to provide benchmarks. Calculated subcritical limits contain an adequate but not excessive margin to allow for uncertainty in the bias. The final step in any criticality safety evaluation is the writing of a report describing the calculations and justifying the margin

  7. Limitations of systemic accident analysis methods

    Directory of Open Access Journals (Sweden)

    Casandra Venera BALAN

    2016-12-01

    Full Text Available In terms of system theory, the description of complex accidents is not limited to the analysis of the sequence of events / individual conditions, but highlights nonlinear functional characteristics and frames human or technical performance in relation to normal functioning of the system, in safety conditions. Thus, the research of the system entities as a whole is no longer an abstraction of a concrete situation, but an exceeding of the theoretical limits set by analysis based on linear methods. Despite the issues outlined above, the hypothesis that there isn’t a complete method for accident analysis is supported by the nonlinearity of the considered function or restrictions, imposing a broad vision of the elements introduced in the analysis, so it can identify elements corresponding to nominal parameters or trigger factors.

  8. Most household waters below the safety limits

    International Nuclear Information System (INIS)

    Salonen, L.; Annanmaeki, M.

    1994-01-01

    According to guidelines published by the Finnish Centre for Radiation and Nuclear Safety, the radiation dose caused by radioactivity in household water shall not exceed 0.5 millisieverts a year. Most of the water distributed by Finnish waterworks meets this safety goal. According to measurements performed to date, only 20-30 small waterworks or water intake plants have exceeded the limit. Radioactivity in excess of the safety goal is almost invariably caused by a high radon concentration. When ingested, radon causes a radiation dose to the organism; the lungs are also affected when radon is released into the air and then inhalated. Privately owned bored wells, however pose a problem, because the radioactivity of water in some Finnish wells is among the highest in the world. If the same 0.5 millisievert limit was also applied to wells bored for private use, the safety goal would be exceeded by more than half of the wells. (orig.)

  9. Gulf Canada Resources Limited 1998 annual report

    International Nuclear Information System (INIS)

    1999-01-01

    A review of operations in 1998 and financial information from Gulf Canada Resources Limited is provided to keep shareholders abreast of company performance. Gulf Canada Resources Limited explores for, develops, produces and markets conventional and synthetic crude oil, natural gas and natural gas liquids. In 1998, the company's main operating centres were in western Canada (where it owns a nine per cent interest in the Syncrude Joint Venture), Indonesia, the North Sea and Australia. The report summarizes the company's energy resource activities, presents a detailed review of operations, and provides consolidated financial statements, and common share information. Although Gulf Canada Resources sold $ 1.2 billion worth of non-producing assets during the year, year end proved reserves of 838 million barrels of oil equivalent were less than ten per cent lower than a year earlier, reflecting reserve additions of 100 million barrels of oil equivalent. tabs., figs

  10. Penser aux/les limites de nos limites

    Directory of Open Access Journals (Sweden)

    Jacques Lévy

    2010-12-01

    Full Text Available Le mot « frontière » a beaucoup de succès, dans son sens propre mais plus encore comme métaphore d’une multitude de réalités qui ont à voir avec les limites, c’est-à-dire avec notre propension à découper le monde en objets séparables. Mais on constate une grande indétermination entre concept et métaphore et un usage trop facile de mélanges entre ceux-ci. Il faut donc d’abord admettre que la matérialité n’est qu’une des composantes de notre monde, mais que l’immatériel n’est pas l’irréel, le simulé ou le métaphorique. Après un détour par une théorie des limites et ses limites et une distinction entre le topographique (continu et le topologique (discontinu appliquée à l’intérieur et aux limites d’une aire, deux exemples sont développés qui visent à montrer que, si l’on trouve des frontières, ce n’est pas forcément là où on les attend et que l’appréciation juste de la place des frontières suppose la prise en compte de bien d’autres considérations que la seule limitation volontaire et brutale du franchissement d’une ligne imaginaire tracée au sol.Think about limits and the limits of our limitsThe word “boundary” has been very successful in its literal sense but even more so as a metaphor of a multitude of realities involving limits, that is, with regards to our tendency to divide the world into separable objects. However, one can observe a considerable uncertainty between the concept and the metaphor and an utilisation too easy of various mixtures of them. It becomes necessary therefore to first admit that materiality is only one of the components of our world whilst the immaterial is not unreal, simulated or metaphoric. After a detour consisting of examining a theory of limits and its limits and making the distinction between the topographic (continuous and the topologic (discontinuous applied to the interior and the limits of an area, two examples are developed which aim to

  11. ZEPLIN-II limits on WIMP-nucelon interactions

    International Nuclear Information System (INIS)

    Alner, G. J.; Bungau, C.; Camanzi, B.; Durkin, T.; Edwards, B.; Lewin, J. D.; Luescher, R.; Preece, R. M.; Smith, N. J. T.; Smith, P. F.; Sumner, T. J.; Thorne, C.; Araujo, H. M.; Bewick, A.; Davidge, D.; Dawson, J.; Howard, A. S.; Jones, W. G.; Joshi, M.; Lebedenko, V. N.

    2009-01-01

    ZEPLIN II is a two-phase xenon detector designed to detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Following the first 31-day underground run in Boulby Mine, UK, the collaboration published dark matter limits in January 2007; the first such limits using two-phase xenon technology. We outline the key detector design, performance and results here.

  12. 40 CFR 434.63 - Effluent limitations for precipitation events.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Effluent limitations for precipitation... SOURCE PERFORMANCE STANDARDS Miscellaneous Provisions § 434.63 Effluent limitations for precipitation... discharge or increase in the volume of a discharge caused by precipitation within any 24 hour period less...

  13. The ODELIA Study on Noise Limits for Outdoor Machinery

    NARCIS (Netherlands)

    Dittrich, M.G.; Carletti, E.; Spellerberg, G.

    2016-01-01

    In the ODELIA study for the European Commission an assessment of the outdoor equipment noise directive 2000/14/EC and its amendment 2005/88/EC has been performed. The directive requires noise marking for 57 types of equipment used outdoors, and sets noise limits for 22 of these. Since the limits

  14. 40 CFR 60.2215 - What else must I report if I have a deviation from the operating limits or the emission limitations?

    Science.gov (United States)

    2010-07-01

    ... performance test was conducted that deviated from any emission limitation. (b) The deviation report must be... deviation from the operating limits or the emission limitations? 60.2215 Section 60.2215 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR...

  15. 40 CFR 60.2957 - What else must I report if I have a deviation from the operating limits or the emission limitations?

    Science.gov (United States)

    2010-07-01

    ..., or if a performance test was conducted that showed a deviation from any emission limitation. (b) The... deviation from the operating limits or the emission limitations? 60.2957 Section 60.2957 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR...

  16. Globalization and limit to growth

    International Nuclear Information System (INIS)

    Gros, D.

    2009-01-01

    A global financial crisis is not the only concern the world should have. From oil and other commodities new challenges arise, that could be difficult to face properly and could provide another limit to growth. This Malthusian feature of the 21. century emerges clearly if one focuses on climate change. [it

  17. ITER operating limit definition criteria

    International Nuclear Information System (INIS)

    Ciattaglia, S.; Barabaschi, P.; Carretero, J.A.; Chiocchio, S.; Hureau, D.; Girard, J.Ph.; Gordon, C.; Portone, A.; Rodrigo, L. Rodriguez; Roldan, C.; Saibene, G.; Uzan-Elbez, J.

    2009-01-01

    The operating limits and conditions (OLCs) are operating parameters and conditions, chosen among all system/components, which, together, define the domain of the safe operation of ITER in all foreseen ITER states (operation, maintenance, commissioning). At the same time they are selected to guarantee the required operation flexibility which is a critical factor for the success of an experimental machine such as ITER. System and components that are important for personnel or public safety (safety important class, SIC) are identified considering their functional importance in the overall plant safety analysis. SIC classification has to be presented already in the preliminary safety analysis report and approved by the licensing authority before manufacturing and construction. OLCs comprise the safety limits that, if exceeded, could result in a potential safety hazard, the relevant settings that determine the intervention of SIC systems, and the operational limits on equipment which warn against or stop a functional deviation from a planned operational status that could challenge equipment and functions. Some operational conditions, e.g. in-Vacuum Vessel (VV) radioactive inventories, will be controlled through procedures. Operating experience from present tokamaks, in particular JET, and from nuclear plants, is considered to the maximum possible extent. This paper presents the guidelines for the development of the ITER OLCs with particular reference to safety limits.

  18. Functional Limitations in Severe Haemophilia

    NARCIS (Netherlands)

    Genderen, F.R. van

    2006-01-01

    This thesis aims to describe the Disablement Process (DP) in Dutch adult patients with severe haemophilia, with specific focus on the domain of “Functional Limitations”. Four main questions underlie this thesis: How can Functional Limitations in severe haemophilia be investigated? Can the

  19. Limitations of existing web services

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Limitations of existing web services. Uploading or downloading large data. Serving too many user from single source. Difficult to provide computer intensive job. Depend on internet and its bandwidth. Security of data in transition. Maintain confidentiality of data ...

  20. Historical Drawbacks of Limited Liability

    Directory of Open Access Journals (Sweden)

    Denis Boyle

    2016-07-01

    Full Text Available Limited liability is a human invention which has facilitated enormous economic growth around the world, particularly since the time of its general application in advanced countries during the nineteenth century. The individual legal identity of companies, coupled with the limited liability of their owners, has provided protection for investors from the risks associated with their investments. It has thus contributed to increase the sources of capital available to finance projects which might otherwise have been considered unviable. However, the legal protection offered to investors has negative consequences for other participants in economies. Speculation in stock markets often damages society. It is very important to study the drawbacks of limited liability and to suggest modifications to achieve a more stable, less volatile, economic growth in the world. Although this article goes to some lengths to recognise the work of authors who emphasise the positive historical economic contribution of limited lability, its main objective is to provoke a reflection around texts which point out the drawbacks and propose solutions.