Helmholtz bright and boundary solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2007-02-16

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts.

An implicit finite-difference operator for the Helmholtz equation

KAUST Repository

Chu, Chunlei; Stoffa, Paul L.

2012-01-01

We have developed an implicit finite-difference operator for the Laplacian and applied it to solving the Helmholtz equation for computing the seismic responses in the frequency domain. This implicit operator can greatly improve the accuracy of the simulation results without adding significant extra computational cost, compared with the corresponding conventional explicit finite-difference scheme. We achieved this by taking advantage of the inherently implicit nature of the Helmholtz equation and merging together the two linear systems: one from the implicit finite-difference discretization of the Laplacian and the other from the discretization of the Helmholtz equation itself. The end result of this simple yet important merging manipulation is a single linear system, similar to the one resulting from the conventional explicit finite-difference discretizations, without involving any differentiation matrix inversions. We analyzed grid dispersions of the discrete Helmholtz equation to show the accuracy of this implicit finite-difference operator and used two numerical examples to demonstrate its efficiency. Our method can be extended to solve other frequency domain wave simulation problems straightforwardly. © 2012 Society of Exploration Geophysicists.

An implicit finite-difference operator for the Helmholtz equation

KAUST Repository

Chu, Chunlei

2012-07-01

We have developed an implicit finite-difference operator for the Laplacian and applied it to solving the Helmholtz equation for computing the seismic responses in the frequency domain. This implicit operator can greatly improve the accuracy of the simulation results without adding significant extra computational cost, compared with the corresponding conventional explicit finite-difference scheme. We achieved this by taking advantage of the inherently implicit nature of the Helmholtz equation and merging together the two linear systems: one from the implicit finite-difference discretization of the Laplacian and the other from the discretization of the Helmholtz equation itself. The end result of this simple yet important merging manipulation is a single linear system, similar to the one resulting from the conventional explicit finite-difference discretizations, without involving any differentiation matrix inversions. We analyzed grid dispersions of the discrete Helmholtz equation to show the accuracy of this implicit finite-difference operator and used two numerical examples to demonstrate its efficiency. Our method can be extended to solve other frequency domain wave simulation problems straightforwardly. © 2012 Society of Exploration Geophysicists.

Helmholtz resonance in a piezoelectric–hydraulic pump-based hybrid actuator

International Nuclear Information System (INIS)

Kim, Gi-Woo; Wang, K W

2011-01-01

This paper demonstrates that a hydraulically acting Helmholtz resonator can exist in a piezoelectric–hydraulic pump (PHP) based hybrid actuator, which in turn affects the volumetric efficiency of the PHP. The simulation and experimental results illustrate the effect of Helmholtz resonance on the flow rate performance of the PHP. The study also shows how to shift the Helmholtz resonant frequency to a higher value through changing parameters such as the cylinder diameter and the effective bulk modulus of the working fluid, which will improve the volumetric efficiency and broaden the operating frequency range of the PHP actuator

Simulation of Helmholtz Resonance Effects in Aircraft ECS

OpenAIRE

Pollok, Alexander; Schröffer, Andreas

2017-01-01

Helmholtz resonators are closed volumes that are connected to pipes. They exhibit a pronounced resonance frequency, where small boundary pressure excitations in the volume or the environment lead to large mass flow excitations in the pipe. Aircraft have a topology similar to Helmholtz resonators, the closed volume is represented by the cabin, while the pipe is represented by the Environmental Control System. Some discrepancies appear due to the non-zero mass-flow or friction effects in...

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Safety Research. Annual report 2010

Energy Technology Data Exchange (ETDEWEB)

Gerbeth, Gunter; Schaefer, Frank (eds.)

2011-07-01

The Institute of Safety Research (ISR) was over the past 20 years one of the six Research Institutes of Forschungszentrum Dresden-Rossendorf e.V. (FZD), which in 2010 belonged to the Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz. Together with the Institutes of Radiochemistry and Radiation Physics, ISR implements the research programme ''Nuclear Safety Research'' (NSR), which was during last years one of the three scientific programmes of FZD. NSR involves two main topics, i.e. ''Safety Research for Radioactive Waste Disposal'' and ''Safety Research for Nuclear Reactors''. The research of ISR aims at assessing and enhancing the safety of current and future reactors, the development of advanced simulation tools including their validation against experimental data, and the development of the appropriate measuring techniques for multi-phase flows and liquid metals.

Helmholtz-Zentrum Dresden-Rossendorf, Institute of Safety Research. Annual report 2010

International Nuclear Information System (INIS)

Gerbeth, Gunter; Schaefer, Frank

2011-01-01

The Institute of Safety Research (ISR) was over the past 20 years one of the six Research Institutes of Forschungszentrum Dresden-Rossendorf e.V. (FZD), which in 2010 belonged to the Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz. Together with the Institutes of Radiochemistry and Radiation Physics, ISR implements the research programme ''Nuclear Safety Research'' (NSR), which was during last years one of the three scientific programmes of FZD. NSR involves two main topics, i.e. ''Safety Research for Radioactive Waste Disposal'' and ''Safety Research for Nuclear Reactors''. The research of ISR aims at assessing and enhancing the safety of current and future reactors, the development of advanced simulation tools including their validation against experimental data, and the development of the appropriate measuring techniques for multi-phase flows and liquid metals.

Kelvin-Helmholtz instability as a possible cause of edge localized modes

International Nuclear Information System (INIS)

Strauss, H.R.

1992-01-01

Edge localized modes may be a Kelvin-Helmholtz instability caused by the sheared rotation of H-mode plasmas. The Kelvin-Helmholtz instability is stabilized by coupling to Alfven waves. There is a critical velocity gradient, of the order of the Alfven velocity divided by the magnetic shear length. This is verified in a numerical simulation. The critical velocity shear is consistent with experiment. A non-linear simulation shows how the Kelvin-Helmholtz mode can cause oscillations of the velocity profile. (author). Letter-to-the-editor. 13 refs, 6 figs

Noise reduction efficiency of Helmholtz resonator in simulated channel of HVAC system

Directory of Open Access Journals (Sweden)

Hossein Ali Yousefi Rizi

2014-01-01

Conclusions: This research showed that the designed Helmholtz resonators at a certain frequency of low-frequency sound demonstrated the soundest decrease. The increase in the Helmholtz resonators′ chamber volume and their neck′s pass area are negatively associated with the rate of sound resonance. As a result, of determining the effective frequency range of the Helmholtz resonator, the designed resonator could be applied as an effective and efficient instrument of removing or decreasing noise.

Helmholtz solitons in power-law optical materials

International Nuclear Information System (INIS)

Christian, J. M.; McDonald, G. S.; Potton, R. J.; Chamorro-Posada, P.

2007-01-01

A nonlinear Helmholtz equation for optical materials with regimes of power-law type of nonlinearity is proposed. This model captures the evolution of broad beams at any angle with respect to the reference direction in a wide range of media, including some semiconductors, doped glasses, and liquid crystals. Exact analytical soliton solutions are presented for a generic nonlinearity, within which known Kerr solitons comprise a subset. Three general conservation laws are also reported. Analysis and numerical simulations examine the stability of the Helmholtz power-law solitons. A propagation feature, associated with spatial solitons in power-law media, constituting a class of oscillatory solution, is identified

Bistable Helmholtz solitons in cubic-quintic materials

International Nuclear Information System (INIS)

Christian, J. M.; McDonald, G. S.; Chamorro-Posada, P.

2007-01-01

We propose a nonlinear Helmholtz equation for modeling the evolution of broad optical beams in media with a cubic-quintic intensity-dependent refractive index. This type of nonlinearity is appropriate for some semiconductor materials, glasses, and polymers. Exact analytical soliton solutions are presented that describe self-trapped nonparaxial beams propagating at any angle with respect to the reference direction. These spatially symmetric solutions are, to the best of our knowledge, the first bistable Helmholtz solitons to be derived. Accompanying conservation laws (both integral and particular forms) are also reported. Numerical simulations investigate the stability of the solitons, which appear to be remarkably robust against perturbations

On Helmholtz Problem for Plane Periodical Structures

International Nuclear Information System (INIS)

Akishin, P.G.; Vinitskij, S.I.

1994-01-01

The plane Helmholtz problem of the periodical disc structures with the phase shifts conditions of the solutions along the basis lattice vectors and the Dirichlet conditions on the basic boundaries is considered. The Green function satisfying the quasi periodical conditions on the lattice is constructed. The Helmholtz problem is reduced to the boundary integral equations for the simple layer potentials of this Green function. The methods of the discretization of the arising integral equations are proposed. The procedures of calculation of the matrix elements are discussed. The reality of the spectral parameter of the nonlinear continuous and discretized problems is shown. 8 refs., 2 figs

Upgrade of long trace profiler for characterization of high-precision X-ray mirrors at SPring-8

International Nuclear Information System (INIS)

Senba, Y.; Kishimoto, H.; Ohashi, H.; Yumoto, H.; Zeschke, T.; Siewert, F.; Goto, S.; Ishikawa, T.

2010-01-01

The long trace profiler (LTP) at SPring-8 has been upgraded to improve stability and resolution of slope measurement. The performances of the upgraded LTP at SPring-8 are presented by cross-checking measurements on a flat mirror with data obtained using Nanometer Optical Component Measuring Machine (NOM) at the Helmholtz Zentrum Berlin/BESSY-II.

Bistable dark solitons of a cubic-quintic Helmholtz equation

International Nuclear Information System (INIS)

Christian, J. M.; McDonald, G. S.; Chamorro-Posada, P.

2010-01-01

We provide a report on exact analytical bistable dark spatial solitons of a nonlinear Helmholtz equation with a cubic-quintic refractive-index model. Our analysis begins with an investigation of the modulational instability characteristics of Helmholtz plane waves. We then derive a dark soliton by mapping the desired asymptotic form onto a uniform background field and obtain a more general solution by deploying rotational invariance laws in the laboratory frame. The geometry of the new soliton is explored in detail, and a range of new physical predictions is uncovered. Particular attention is paid to the unified phenomena of arbitrary-angle off-axis propagation and nondegenerate bistability. Crucially, the corresponding solution of paraxial theory emerges in a simultaneous multiple limit. We conclude with a set of computer simulations that examine the role of Helmholtz dark solitons as robust attractors.

Helmholtz and Zoellner: nineteenth-century empiricism, spiritism, and the theory of space perception.

Science.gov (United States)

Stromberg, W H

1989-10-01

J. K. F. Zoellner began writing on "experimental proofs" of a fourth spatial dimension, and of the existence of spirits, in 1878. His arguments caused strong controversy, with rebuttal essays by Wilhelm Wundt and others. The author argues that Zoellner's case that these matters are experimental questions rested on arguments which Hermann von Helmholtz, inveighing against rationalist views of space and space perception, had recently published. Zoellner's use of Helmholtz's arguments to advance and defend his spiritist views occasioned strong criticism of Helmholtz, affected careers and reputations of scholars in Berlin and Leipzig, and caused enduring controversy over the credibility of Helmholtz's empiricist theory of space perception.

Symmetry-breaking analysis for the general Helmholtz-Duffing oscillator

International Nuclear Information System (INIS)

Cao Hongjun; Seoane, Jesus M.; Sanjuan, Miguel A.F.

2007-01-01

The symmetry breaking phenomenon for a general Helmholtz-Duffing oscillator as a function of a symmetric parameter in the nonlinear force is investigated. Different values of this parameter convert the general oscillator into either the Helmholtz or the Duffing oscillator. Due to the variation of the symmetric parameter, the phase space patterns of the unperturbed Helmholtz-Duffing oscillator will cause a huge difference between the left-hand homoclinic orbit and the right-hand one. In particular, the area of the left-hand homoclinic orbits is a strictly monotonously decreasing function, while the area of the right-hand homoclinic orbit varies only in a very small range. There exist distinct local supercritical and subcritical saddle-node bifurcations at two different centers. The left-hand and the right-hand existing regions of the harmonic solutions of the Helmholtz-Duffing oscillator created by the left-hand and the right-hand saddle-node bifurcation curves will lead to different transition in the amplitude-frequency plane. There exists also a critical frequency which has the effect that the left-hand homoclinic bifurcation value is equal to the right-hand homoclinic bifurcation value. And, if the amplitude coefficient of the Helmholtz-Duffing oscillator is used as the control parameter, and it is larger than the same left-hand and right-hand homoclinic bifurcation, then the global stability of the system will be destroyed at a lowest cost. Besides this critical frequency, the left-hand and the right-hand homoclinic bifurcations are not only unequal, but also their effects for the system's stability are different. Among them, the effect resulting from the small homoclinic bifurcation for the system's stability is local and negligible, while the effect from the large homoclinic bifurcation is global but this is accomplished at a quite larger cost

The Determinate World Kant and Helmholtz on the Physical Meaning of Geometry

CERN Document Server

Hyder, David

2009-01-01

This study examines the place of Hermann von Helmholtz´s seminal papers on geometry in his philosophy of science. The arguments of these papers are traced back to his prior work on the theory of magnitudes, as well as to Helmholtz´s early, Kantian position. The author claims that Helmholtz should be understood not as opposing Kant, but as modifying the latter´s theory of magnitudes so as to remove obstacles to their common project of constructing a complete system of natural science.

Helmholtz algebraic solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M; McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Materials and Physics Research Centre, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P, E-mail: j.christian@salford.ac.u [Departamento de Teoria de la Senal y Comunicaciones e Ingenieria Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2010-02-26

We report, to the best of our knowledge, the first exact analytical algebraic solitons of a generalized cubic-quintic Helmholtz equation. This class of governing equation plays a key role in photonics modelling, allowing a full description of the propagation and interaction of broad scalar beams. New conservation laws are presented, and the recovery of paraxial results is discussed in detail. The stability properties of the new solitons are investigated by combining semi-analytical methods and computer simulations. In particular, new general stability regimes are reported for algebraic bright solitons.

Helmholtz algebraic solitons

International Nuclear Information System (INIS)

Christian, J M; McDonald, G S; Chamorro-Posada, P

2010-01-01

We report, to the best of our knowledge, the first exact analytical algebraic solitons of a generalized cubic-quintic Helmholtz equation. This class of governing equation plays a key role in photonics modelling, allowing a full description of the propagation and interaction of broad scalar beams. New conservation laws are presented, and the recovery of paraxial results is discussed in detail. The stability properties of the new solitons are investigated by combining semi-analytical methods and computer simulations. In particular, new general stability regimes are reported for algebraic bright solitons.

Solving the Helmholtz equation in conformal mapped ARROWstructures using homotopy perturbation method

DEFF Research Database (Denmark)

Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

2011-01-01

. The solution of the mapped Helmholtz equation is found by solving an infinite series of Poisson equations using two dimensional Fourier series. The solution is entirely based on analytical expressions and is not mesh dependent. The analytical results are compared to a numerical (finite element method) solution......The scalar wave equation, or Helmholtz equation, describes within a certain approximation the electromagnetic field distribution in a given system. In this paper we show how to solve the Helmholtz equation in complex geometries using conformal mapping and the homotopy perturbation method...

Transmission problems for the Helmholtz equation for a rectilinear-circular lune

Directory of Open Access Journals (Sweden)

Volodymyr Denysenko

2007-01-01

Full Text Available The question related to the construction of the solution of plane transmission problem for the Helmholtz equation in a rectilinear-circular lune is considered. An approach is proposed based on the method of partial domains and the principle of reflection for the solutions of the Helmholtz equation through the segment.

Acoustic superlens using Helmholtz-resonator-based metamaterials

International Nuclear Information System (INIS)

Yang, Xishan; Yin, Jing; Yu, Gaokun; Peng, Linhui; Wang, Ning

2015-01-01

Acoustic superlens provides a way to overcome the diffraction limit with respect to the wavelength of the bulk wave in air. However, the operating frequency range of subwavelength imaging is quite narrow. Here, an acoustic superlens is designed using Helmholtz-resonator-based metamaterials to broaden the bandwidth of super-resolution. An experiment is carried out to verify subwavelength imaging of double slits, the imaging of which can be well resolved in the frequency range from 570 to 650 Hz. Different from previous works based on the Fabry-Pérot resonance, the corresponding mechanism of subwavelength imaging is the Fano resonance, and the strong coupling between the neighbouring Helmholtz resonators separated at the subwavelength interval leads to the enhanced sound transmission over a relatively wide frequency range

The Helmholtz legacy in physiological acoustics

CERN Document Server

Hiebert, Erwin

2014-01-01

This book explores the interactions between science and music in the late nineteenth- and early twentieth century. It examines and evaluates the work of Hermann von Helmholtz, Max Planck, Shohe Tanaka, and Adriaan Fokker, leading physicists and physiologists who were committed to understanding crucial aesthetic components of the art of music, including the standardization of pitch and the implementation of various types of intonations. With a mixture of physics, physiology, and aesthetics, author Erwin Hiebert addresses throughout the book how just intonation came to intersect with the history of keyboard instruments and exert an influence on the development of Western music. He begins with the work of Hermann von Helmholtz, a leading nineteenth-century physicist and physiologist who not only made important contributions in vision, optics, electrodynamics and thermodynamics, but also helped advanced the field of music theory as well. The author traces the Helmholtzian trends of thought that become inherently ...

The Helmholtz Hierarchy: Phase Space Statistics of Cold Dark Matter

OpenAIRE

Tassev, Svetlin

2010-01-01

We present a new formalism to study large-scale structure in the universe. The result is a hierarchy (which we call the "Helmholtz Hierarchy") of equations describing the phase space statistics of cold dark matter (CDM). The hierarchy features a physical ordering parameter which interpolates between the Zel'dovich approximation and fully-fledged gravitational interactions. The results incorporate the effects of stream crossing. We show that the Helmholtz hierarchy is self-consistent and obeys...

Optics for Advanced Neutron Imaging and Scattering

International Nuclear Information System (INIS)

Moncton, David E.; Khaykovich, Boris

2016-01-01

During the report period, we continued the work as outlined in the original proposal. We have analyzed potential optical designs of Wolter mirrors for the neutron-imaging instrument VENUS, which is under construction at SNS. In parallel, we have conducted the initial polarized imaging experiment at Helmholtz Zentrum, Berlin, one of very few of currently available polarized-imaging facilities worldwide.

Annual report 2012. Institute of Resource Ecology

International Nuclear Information System (INIS)

Brendler, Vinzenz

2013-01-01

The Institute of Resource Ecology (IRE) is one of the currently eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the program ''Nuclear Safety Research'' of the Helmholtz Association and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. With the integration of the division of ''Reactor Safety'' from the former ''Institute of Safety Research'' nuclear research at HZDR is now mainly concentrated within this institute. In addition, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. Here, a knowledge transfer from the nuclear to the non-nuclear community, branching thermodynamics and spectroscopy, has been established. This also strengthens links to the recently established ''Helmholtz-Institute Freiberg for Resource Technology''.

Annual report 2012. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Brendler, Vinzenz [ed.

2013-09-01

The Institute of Resource Ecology (IRE) is one of the currently eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the program ''Nuclear Safety Research'' of the Helmholtz Association and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. With the integration of the division of ''Reactor Safety'' from the former ''Institute of Safety Research'' nuclear research at HZDR is now mainly concentrated within this institute. In addition, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. Here, a knowledge transfer from the nuclear to the non-nuclear community, branching thermodynamics and spectroscopy, has been established. This also strengthens links to the recently established ''Helmholtz-Institute Freiberg for Resource Technology''.

Thin-Layer Solutions of the Helmholtz and Related Equations

KAUST Repository

Ockendon, J. R.

2012-01-01

This paper concerns a certain class of two-dimensional solutions to four generic partial differential equations-the Helmholtz, modified Helmholtz, and convection-diffusion equations, and the heat conduction equation in the frequency domain-and the connections between these equations for this particular class of solutions.S pecifically, we consider thin-layer solutions, valid in narrow regions across which there is rapid variation, in the singularly perturbed limit as the coefficient of the Laplacian tends to zero.F or the wellstudied Helmholtz equation, this is the high-frequency limit and the solutions in question underpin the conventional ray theory/WKB approach in that they provide descriptions valid in some of the regions where these classical techniques fail.E xamples are caustics, shadow boundaries, whispering gallery, and creeping waves and focusing and bouncing ball modes.It transpires that virtually all such thin-layer models reduce to a class of generalized parabolic wave equations, of which the heat conduction equation is a special case. Moreover, in most situations, we will find that the appropriate parabolic wave equation solutions can be derived as limits of exact solutions of the Helmholtz equation.W e also show how reasonably well-understood thin-layer phenomena associated with any one of the four generic equations may translate into less well-known effects associated with the others.In addition, our considerations also shed some light on the relationship between the methods of matched asymptotic, WKB, and multiple-scales expansions. © 2012 Society for Industrial and Applied Mathematics.

Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

NARCIS (Netherlands)

Matova, S.P.; Elfrink, R.; Vullers, R.J.M.; Schaijk, R. van

2011-01-01

In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with

Another Look at Helmholtz's Model for the Gravitational Contraction of the Sun

Science.gov (United States)

Tort, A. C.; Nogarol, F.

2011-01-01

We take another look at the Helmholtz model for the gravitational contraction of the Sun. We show that there are two other pedagogically useful ways of rederiving Helmholtz's main results that make use of Gauss's law, the concept of gravitational field energy and the work-kinetic energy theorem. An account of the energy balance involved in the…

THEREDA. Thermodynamic reference data base. Phase II. Release of thermodynamic data. Summary and final report; THEREDA. Thermodynamische Referenz-Datenbasis. Phase II. Freigabe thermodynamischer Daten. Zusammenfassung der Abschlussberichte

Energy Technology Data Exchange (ETDEWEB)

Altmaier, Marcus; Gaona, Xavier; Marquardt, Christian; Montoya, Vanessa [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Institut fuer Nukleare Entsorgung; Bok, Frank; Richter, Anke [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Moog, Helge C.; Scharge, Tina [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany); Voigt, Wolfgang [Technische Univ. Bergakademie Freiberg (Germany); Wilhelm, Stefan [AF Consult AG, Baden-Daettwil (Switzerland)

2015-12-15

The final report on the thermodynamic reference data base THEREDA covers the following issues: project management, quality management (Helmholtz-Zentrum Dresden-Rossendorf HZDR and GRS), data base interfaces, documentation, uranium (HZDR), other nuclides (Karlsruhe Institute for technology, KIT), data for cement minerals and their reaction products (AF-Consult, GRS), phosphate (GRS), systems with CO2 and carbonate at variable temperatures and pressure (Bergakademie Freiberg, TUBAF).

From Helmholtz to Schlick: The evolution of the sign-theory of perception.

Science.gov (United States)

Oberdan, Thomas

2015-08-01

Efforts to trace the influence of fin de siècle neo-Kantianism on early 20th Century philosophy of science have led scholars to recognize the powerful influence on Moritz Schlick of Hermann von Helmholtz, the doyen of 19th Century physics and a leader of the zurȕck zu Kant movement. But Michael Friedman thinks that Schlick misunderstood Helmholtz' signature philosophical doctrine, the sign-theory of perception. Indeed, Friedman has argued that Schlick transformed Helmholtz' Kantian view of spatial intuition into an empiricist version of the causal theory of perception. However, it will be argued that, despite the key role the sign-theory played in his epistemology, Schlick thought the Kantianism in Helmholtz' thought was deeply flawed, rendered obsolete by philosophical insights which emerged from recent scientific developments. So even though Schlick embraced the sign-theory, he rejected Helmholtz' ideas about spatial intuition. In fact, like his teacher, Max Planck, Schlick generalized the sign-theory into a form of structural realism. At the same time, Schlick borrowed the method of concept-formation developed by the formalist mathematicians, Moritz Pasch and David Hilbert, and combined it with the conventionalism of Henri Poincaré. Then, to link formally defined concepts with experience, Schlick's introduced his 'method of coincidences', similar to the 'point-coincidences' featured in Einstein's physics. The result was an original scientific philosophy, which owed much to contemporary scientific thinkers, but little to Kant or Kantianism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Riemann's and Helmholtz-Lie's problems of space from Weyl's relativistic perspective

Science.gov (United States)

Bernard, Julien

2018-02-01

I reconstruct Riemann's and Helmholtz-Lie's problems of space, from some perspectives that allow for a fruitful comparison with Weyl. In Part II. of his inaugural lecture, Riemann justifies that the infinitesimal metric is the square root of a quadratic form. Thanks to Finsler geometry, I clarify both the implicit and explicit hypotheses used for this justification. I explain that Riemann-Finsler's kind of method is also appropriate to deal with indefinite metrics. Nevertheless, Weyl shares with Helmholtz a strong commitment to the idea that the notion of group should be at the center of the foundations of geometry. Riemann missed this point, and that is why, according to Weyl, he dealt with the problem of space in a "too formal" way. As a consequence, to solve the problem of space, Weyl abandoned Riemann-Finsler's methods for group-theoretical ones. However, from a philosophical point of view, I show that Weyl and Helmholtz are in strong opposition. The meditation on Riemann's inaugural lecture, and its clear methodological separation between the infinitesimal and the finite parts of the problem of space, must have been crucial for Weyl, while searching for strong epistemological foundations for the group-theoretical methods, avoiding Helmholtz's unjustified transition from the finite to the infinitesimal.

The Helmholtz Hierarchy: phase space statistics of cold dark matter

International Nuclear Information System (INIS)

Tassev, Svetlin V.

2011-01-01

We present a new formalism to study large-scale structure in the universe. The result is a hierarchy (which we call the ''Helmholtz Hierarchy'') of equations describing the phase space statistics of cold dark matter (CDM). The hierarchy features a physical ordering parameter which interpolates between the Zel'dovich approximation and fully-fledged gravitational interactions. The results incorporate the effects of stream crossing. We show that the Helmholtz hierarchy is self-consistent and obeys causality to all orders. We present an interpretation of the hierarchy in terms of effective particle trajectories

Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

International Nuclear Information System (INIS)

Matova, S P; Elfrink, R; Vullers, R J M; Van Schaijk, R

2011-01-01

In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adjustable resonance frequencies have been designed—one with a solid bottom and one with membrane on the bottom. The resonance frequencies of the resonators were matched to the complementing piezoelectric harvesters during harvesting. The aim of the presented work is a feasibility study on using packaged piezoelectric energy harvesters with Helmholtz resonators for airflow energy harvesting. The maximum energy we were able to obtain was 42.2 µW at 20 m s −1

Multimode Coupling Theory for Kelvin–Helmholtz Instability in Incompressible Fluid

International Nuclear Information System (INIS)

Li-Feng, Wang; Ying-Jun, Li; Wen-Hua, Ye; Zheng-Feng, Fan

2009-01-01

A weakly nonlinear model is proposed for multimode Kelvin–Helmholtz instability. The second-order mode coupling formula for Kelvin–Helmholtz instability in two-dimensional incompressible fluid is presented by expanding the perturbation velocity potential to second order. It is found that there is an important resonance in the course of the sum frequency mode coupling but the difference frequency mode coupling does not have. This resonance makes the sum frequency mode coupling process relatively complex. The sum frequency mode coupling is strongly dependent on time especially when the density of the two fluids is adjacent and the difference frequency mode coupling is not

Reconstruction of extended sources for the Helmholtz equation

KAUST Repository

Kress, Rainer; Rundell, William

2013-01-01

The basis of most imaging methods is to detect hidden obstacles or inclusions within a body when one can only make measurements on an exterior surface. Our underlying model is that of inverse acoustic scattering based on the Helmholtz equation. Our

Rayleigh-Taylor and Kelvin-Helmholtz instabilities in targets accelerated by laser ablation

International Nuclear Information System (INIS)

Emery, M.H.; Gardner, J.H.; Boris, J.P.

1982-01-01

With use of the fast2d laser-shell model, the acceleration of a 20-μm-thick plastic foil up to 160 km/s has been simulated. It is possible to follow the Rayleigh-Taylor bubble-and-spike development far into the nonlinear regime and beyond the point of foil fragmentation. Strong shear flow develops which evolves into the Kelvin-Helmholtz instability. The Kelvin-Helmholtz instability causes the tips of the spikes to widen and as a result reduce their rate of ''fall.''

Fourier-Based Fast Multipole Method for the Helmholtz Equation

KAUST Repository

Cecka, Cris

2013-01-01

The fast multipole method (FMM) has had great success in reducing the computational complexity of solving the boundary integral form of the Helmholtz equation. We present a formulation of the Helmholtz FMM that uses Fourier basis functions rather than spherical harmonics. By modifying the transfer function in the precomputation stage of the FMM, time-critical stages of the algorithm are accelerated by causing the interpolation operators to become straightforward applications of fast Fourier transforms, retaining the diagonality of the transfer function, and providing a simplified error analysis. Using Fourier analysis, constructive algorithms are derived to a priori determine an integration quadrature for a given error tolerance. Sharp error bounds are derived and verified numerically. Various optimizations are considered to reduce the number of quadrature points and reduce the cost of computing the transfer function. © 2013 Society for Industrial and Applied Mathematics.

Annual report 2012. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Brendler, Vinzenz (ed.)

2013-09-01

The Institute of Resource Ecology (IRE) is one of the currently eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the program ''Nuclear Safety Research'' of the Helmholtz Association and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. With the integration of the division of ''Reactor Safety'' from the former ''Institute of Safety Research'' nuclear research at HZDR is now mainly concentrated within this institute. In addition, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. Here, a knowledge transfer from the nuclear to the non-nuclear community, branching thermodynamics and spectroscopy, has been established. This also strengthens links to the recently established ''Helmholtz-Institute Freiberg for Resource Technology''.

Optimization of field homogeneity of Helmholtz-like coils for measuring the balance of planar gradiometers

International Nuclear Information System (INIS)

Nordahn, M.A.; Holst, T.; Shen, Y.Q.

1999-01-01

Measuring the balance of planar SQUID gradiometers using a relatively small Helmholtz-like coil system requires a careful design of the coils in order to have a high degree of field uniformity along the radial direction. The level to which planar gradiometers can be balanced will be affected by any misalignment of the gradiometer relative to the ideal central position. Therefore, the maximum degree of balancing possible is calculated numerically for the Helmholtz geometry under various perturbations, including misalignment of the gradiometer along the cylindrical and the radial axis, and angular tilting relative to the normal plane. Furthermore, if the ratio between the coil separation and coil radius is chosen to be less than unity, calculations show that the expected radial uniformity of the field can be improved considerably compared to the traditional Helmholtz geometry. The optimized coil geometry is compared to the Helmholtz geometry and is found to yield up to an order of magnitude improvement of the worst case error signal within a volume spanned by the uncertainty in the alignment. (author)

Square Helmholtz coil with homogeneous field for magnetic measurement of longer HTS tapes

Energy Technology Data Exchange (ETDEWEB)

Alamgir, A.K.M. [Applied Superconductivity Research Center, Department of Physics, Building Li Zhai, Room 209, Tsinghua University, Beijing 100084 (China)]. E-mail: alam643@hotmail.com; Fang, J. [Applied Superconductivity Research Center, Department of Physics, Building Li Zhai, Room 209, Tsinghua University, Beijing 100084 (China); Gu, C. [Applied Superconductivity Research Center, Department of Physics, Building Li Zhai, Room 209, Tsinghua University, Beijing 100084 (China); Han, Z. [Applied Superconductivity Research Center, Department of Physics, Building Li Zhai, Room 209, Tsinghua University, Beijing 100084 (China)

2005-08-01

Magnetic ac loss measurement of HTS tapes and films at various magnetic field orientations becomes a crucial issue from the view point of measurement precision. In principle, due to tiny loss component and anisotropic properties, longer HTS sample subjected to very good homogeneous field could facilitate the accuracy of this kind of measurement. We investigated field profile of Helmholtz coils with square winding as a magnetizer for HTS tape and films. It is found that square winding exhibits better field-homogeneity than that of conventional circular winding with the similar coil dimensions for ideal condition. Being apart from ideal condition, we investigated field profile of square Helmholtz coil with various combinations of coil parameters and made a conclusion for the best combination based on the field homogeneity and field intensity. The design also provides noise reduction facilities by allowing compact and identical pick up-compensation coil arrangement. In addition, we optimized the final design of Helmholtz coil to compensate the influence of difficulties in square winding on the field distribution. Finally, as small as 0.5% field variation was estimated for 50 mm long sample to be magnetized under a proper combination of fabrication parameters. Investigation of field homogeneity, noise effect and a practical design of square Helmholtz coil as a pick-up coil based magnetizer will be reported.

Square Helmholtz coil with homogeneous field for magnetic measurement of longer HTS tapes

International Nuclear Information System (INIS)

Alamgir, A.K.M.; Fang, J.; Gu, C.; Han, Z.

2005-01-01

Magnetic ac loss measurement of HTS tapes and films at various magnetic field orientations becomes a crucial issue from the view point of measurement precision. In principle, due to tiny loss component and anisotropic properties, longer HTS sample subjected to very good homogeneous field could facilitate the accuracy of this kind of measurement. We investigated field profile of Helmholtz coils with square winding as a magnetizer for HTS tape and films. It is found that square winding exhibits better field-homogeneity than that of conventional circular winding with the similar coil dimensions for ideal condition. Being apart from ideal condition, we investigated field profile of square Helmholtz coil with various combinations of coil parameters and made a conclusion for the best combination based on the field homogeneity and field intensity. The design also provides noise reduction facilities by allowing compact and identical pick up-compensation coil arrangement. In addition, we optimized the final design of Helmholtz coil to compensate the influence of difficulties in square winding on the field distribution. Finally, as small as 0.5% field variation was estimated for 50 mm long sample to be magnetized under a proper combination of fabrication parameters. Investigation of field homogeneity, noise effect and a practical design of square Helmholtz coil as a pick-up coil based magnetizer will be reported

First results with the novel petawatt laser acceleration facility in Dresden

International Nuclear Information System (INIS)

Schramm, U; Bussmann, M; Irman, A; Siebold, M; Zeil, K; Albach, D; Bernert, C; Bock, S; Brack, F; Branco, J; Couperus, JP; Cowan, TE; Debus, A; Eisenmann, C; Garten, M; Gebhardt, R; Grams, S; Helbig, U; Huebl, A; Kluge, T

2017-01-01

We report on first commissioning results of the DRACO Petawatt ultra-short pulse laser system implemented at the ELBE center for high power radiation sources of Helmholtz-Zentrum Dresden-Rossendorf. Key parameters of the laser system essential for efficient and reproducible performance of plasma accelerators are presented and discussed with the demonstration of 40 MeV proton acceleration under TNSA conditions as well as peaked electron spectra with unprecedented bunch charge in the 0.5 nC range. (paper)

48{sup th} Annual meeting on nuclear technology (AMNT 2017). Workshop: Preserving competence in nuclear technology

Energy Technology Data Exchange (ETDEWEB)

Steinwarz, Wolfgang

2017-10-15

On the 19{sup th} workshop ''Preserving Competence in Nuclear Technology'' 17 young scientists presented the results from their thesis work for a diploma, mastership or a PhD covering a broad spectrum of technical areas. This demonstrated again the strong engagement of the younger generation for the nuclear technology and the significant support by the involved German institutions. The jury awarded Thomas Schaefer (Helmholtz-Zentrum Dresden- Rossendorf) with the Siempelkamp Competence Price 2017.

Korteweg-de Vries description of Helmholtz-Kerr dark solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom) ; Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2006-12-15

A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations.

Korteweg-de Vries description of Helmholtz-Kerr dark solitons

International Nuclear Information System (INIS)

Christian, J M; McDonald, G S; Chamorro-Posada, P

2006-01-01

A wide variety of different physical systems can be described by a relatively small set of universal equations. For example, small-amplitude nonlinear Schroedinger dark solitons can be described by a Korteweg-de Vries (KdV) equation. Reductive perturbation theory, based on linear boosts and Gallilean transformations, is often employed to establish connections to and between such universal equations. Here, a novel analytical approach reveals that the evolution of small-amplitude Helmholtz-Kerr dark solitons is also governed by a KdV equation. This broadens the class of nonlinear systems that are known to possess KdV soliton solutions, and provides a framework for perturbative analyses when propagation angles are not negligibly small. The derivation of this KdV equation involves an element that appears new to weakly nonlinear analyses, since transformations are required to preserve the rotational symmetry inherent to Helmholtz-type equations

Kelvin-Helmholtz Instability: Lessons Learned and Ways Forward

Science.gov (United States)

Masson, A.; Nykyri, K.

2018-06-01

The Kelvin-Helmholtz instability (KHI) is a ubiquitous phenomenon across the Universe, observed from 500 m deep in the oceans on Earth to the Orion molecular cloud. Over the past two decades, several space missions have enabled a leap forward in our understanding of this phenomenon at the Earth's magnetopause. Key results obtained by these missions are first presented, with a special emphasis on Cluster and THEMIS. In particular, as an ideal instability, the KHI was not expected to produce mass transport. Simulations, later confirmed by spacecraft observations, indicate that plasma transport in Kelvin-Helmholtz (KH) vortices can arise during non-linear stage of its development via secondary process. In addition to plasma transport, spacecraft observations have revealed that KHI can also lead to significant ion heating due to enhanced ion-scale wave activity driven by the KHI. Finally, we describe what are the upcoming observational opportunities in 2018-2020, thanks to a unique constellation of multi-spacecraft missions including: MMS, Cluster, THEMIS, Van Allen Probes and Swarm.

Capillary and viscous perturbations to Helmholtz flows

KAUST Repository

Moore, M. R.; Ockendon, H.; Ockendon, J. R.; Oliver, J. M.

2014-01-01

Inspired by recent calculations by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, p. 264506) relating to droplet impact, this paper presents an analysis of the perturbations to the free surface caused by small surface tension and viscosity in steady Helmholtz flows. In particular, we identify the regimes in which appreciable vorticity can be shed from the boundary layer to the bulk flow. © 2014 Cambridge University Press.

Capillary and viscous perturbations to Helmholtz flows

KAUST Repository

Moore, M. R.

2014-02-21

Inspired by recent calculations by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, p. 264506) relating to droplet impact, this paper presents an analysis of the perturbations to the free surface caused by small surface tension and viscosity in steady Helmholtz flows. In particular, we identify the regimes in which appreciable vorticity can be shed from the boundary layer to the bulk flow. © 2014 Cambridge University Press.

Magnetized Kelvin-Helmholtz instability: theory and simulations in the Earth's magnetosphere context

Science.gov (United States)

Faganello, Matteo; Califano, Francesco

2017-12-01

The Kelvin-Helmholtz instability, proposed a long time ago for its role in and impact on the transport properties at magnetospheric flanks, has been widely investigated in the Earth's magnetosphere context. This review covers more than fifty years of theoretical and numerical efforts in investigating the evolution of Kelvin-Helmholtz vortices and how the rich nonlinear dynamics they drive allow solar wind plasma bubbles to enter into the magnetosphere. Special care is devoted to pointing out the main advantages and weak points of the different plasma models that can be adopted for describing the collisionless magnetospheric medium and in underlying the important role of the three-dimensional geometry of the system.

Voluntarism in early psychology: the case of Hermann von Helmholtz.

Science.gov (United States)

De Kock, Liesbet

2014-05-01

The failure to recognize the programmatic similarity between (post-)Kantian German philosophy and early psychology has impoverished psychology's historical self-understanding to a great extent. This article aims to contribute to recent efforts to overcome the gaps in the historiography of contemporary psychology, which are the result of an empiricist bias. To this end, we present an analysis of the way in which Hermann von Helmholtz's theory of perception resonates with Johann Gottlieb Fichte's Ego-doctrine. It will be argued that this indebtedness is particularly clear when focusing on the foundation of the differential awareness of subject and object in perception. In doing so, the widespread reception of Helmholtz's work as proto-positivist or strictly empiricist is challenged, in favor of the claim that important elements of his theorizing can only be understood properly against the background of Fichte's Ego-doctrine. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Coupled Kelvin-Helmholtz and Tearing Mode Instabilities at the Mercury's Magnetopause

Science.gov (United States)

Ivanovski, S. L.; Milillo, A.; Kartalev, M.; Massetti, S.

2018-05-01

A MHD approach for numerical simulations of coupled Kelvin-Helmholtz and tearing mode instabilities has been applied to Mercury’s magnetopause and used to perform a physical parameters study constrained by the MESSENGER data.

The outlooks of Helmholtz, Plank and Einstein on the unified physical theory

International Nuclear Information System (INIS)

Treder, G.Yu.

1982-01-01

The outlooks of Helmholtz, Planck and Einstein on the unified physical theory are exposed. Planck formulated the Einstein relativistic mechanics in the canonical form stemming from the suggested by Helmholtz approach that the principle of action is the unified formal principle of physics. Einstein and his companious proceeded from machroscopic fields in the attempts to prove the unified geometric field theory. The sense of Planck length as ''the smallest length in physics'' is determined, on the one hand, by the Heizenberg uncerntainty principle for the measurement process, and on the other hand by the universal proportionality between inertia and gravity. It results from geometrical nature and gravitational potential, i. e. from Einstein interpretation of the equivalence principle

Can Hall effect trigger Kelvin-Helmholtz instability in sub-Alfvénic flows?

Science.gov (United States)

Pandey, B. P.

2018-05-01

In the Hall magnetohydrodynamics, the onset condition of the Kelvin-Helmholtz instability is solely determined by the Hall effect and is independent of the nature of shear flows. In addition, the physical mechanism behind the super- and sub-Alfvénic flows becoming unstable is quite different: the high-frequency right circularly polarized whistler becomes unstable in the super-Alfvénic flows whereas low-frequency, left circularly polarized ion-cyclotron wave becomes unstable in the presence of sub-Alfvénic shear flows. The growth rate of the Kelvin-Helmholtz instability in the super-Alfvénic case is higher than the corresponding ideal magnetohydrodynamic rate. In the sub-Alfvénic case, the Hall effect opens up a new, hitherto inaccessible (to the magnetohydrodynamics) channel through which the partially or fully ionized fluid can become Kelvin-Helmholtz unstable. The instability growth rate in this case is smaller than the super-Alfvénic case owing to the smaller free shear energy content of the flow. When the Hall term is somewhat smaller than the advection term in the induction equation, the Hall effect is also responsible for the appearance of a new overstable mode whose growth rate is smaller than the purely growing Kelvin-Helmholtz mode. On the other hand, when the Hall diffusion dominates the advection term, the growth rate of the instability depends only on the Alfvén -Mach number and is independent of the Hall diffusion coefficient. Further, the growth rate in this case linearly increases with the Alfvén frequency with smaller slope for sub-Alfvénic flows.

Two numerical methods for an inverse problem for the 2-D Helmholtz equation

CERN Document Server

Gryazin, Y A; Lucas, T R

2003-01-01

Two solution methods for the inverse problem for the 2-D Helmholtz equation are developed, tested, and compared. The proposed approaches are based on a marching finite-difference scheme which requires the solution of an overdetermined system at each step. The preconditioned conjugate gradient method is used for rapid solutions of these systems and an efficient preconditioner has been developed for this class of problems. Underlying target applications include the imaging of land mines, unexploded ordinance, and pollutant plumes in environmental cleanup sites, each formulated as an inverse problem for a 2-D Helmholtz equation. The images represent the electromagnetic properties of the respective underground regions. Extensive numerical results are presented.

Preserving the Helmholtz dispersion relation: One-way acoustic wave propagation using matrix square roots

Science.gov (United States)

Keefe, Laurence

2016-11-01

Parabolized acoustic propagation in transversely inhomogeneous media is described by the operator update equation U (x , y , z + Δz) =eik0 (- 1 +√{ 1 + Z }) U (x , y , z) for evolution of the envelope of a wavetrain solution to the original Helmholtz equation. Here the operator, Z =∇T2 + (n2 - 1) , involves the transverse Laplacian and the refractive index distribution. Standard expansion techniques (on the assumption Z << 1)) produce pdes that approximate, to greater or lesser extent, the full dispersion relation of the original Helmholtz equation, except that none of them describe evanescent/damped waves without special modifications to the expansion coefficients. Alternatively, a discretization of both the envelope and the operator converts the operator update equation into a matrix multiply, and existing theorems on matrix functions demonstrate that the complete (discrete) Helmholtz dispersion relation, including evanescent/damped waves, is preserved by this discretization. Propagation-constant/damping-rates contour comparisons for the operator equation and various approximations demonstrate this point, and how poorly the lowest-order, textbook, parabolized equation describes propagation in lined ducts.

Continuous versus discrete structures II -- Discrete Hamiltonian systems and Helmholtz conditions

OpenAIRE

Cresson, Jacky; Pierret, Frédéric

2015-01-01

We define discrete Hamiltonian systems in the framework of discrete embeddings. An explicit comparison with previous attempts is given. We then solve the discrete Helmholtz's inverse problem for the discrete calculus of variation in the Hamiltonian setting. Several applications are discussed.

HNF - Helmholtz Nano Facility

Directory of Open Access Journals (Sweden)

Wolfgang Albrecht

2017-05-01

Full Text Available The Helmholtz Nano Facility (HNF is a state-of-the-art cleanroom facility. The cleanroom has ~1100 m2 with cleanroom classes of DIN ISO 1-3. HNF operates according to VDI DIN 2083, Good Manufacturing Practice (GMP and aquivalent to Semiconductor Industry Association (SIA standards. HNF is a user facility of Forschungszentrum Jülich and comprises a network of facilities, processes and systems for research, production and characterization of micro- and nanostructures. HNF meets the basic supply of micro- and nanostructures for nanoelectronics, fluidics. micromechanics, biology, neutron and energy science, etc.. The task of HNF is rapid progress in nanostructures and their technology, offering efficient access to infrastructure and equipment. HNF gives access to expertise and provides resources in production, synthesis, characterization and integration of structures, devices and circuits. HNF covers the range from basic research to application oriented research facilitating a broad variety of different materials and different sample sizes.

A third note: Helmholtz, Palestrina, and the Early History of Musicology

NARCIS (Netherlands)

Kursell, J.

2015-01-01

This contribution focuses on Hermann von Helmholtz’s work on Renaissance composer Giovanni Pierluigi da Palestrina. Helmholtz used his scientific concept of distortion to analyze this music and, reversely, to find corroboration for the concept in his musical analyses. In this, his work interlocked

Calibration of Helmholtz Coils for the characterization of MEMS magnetic sensor using fluxgate magnetometer with DAS1 magnetic range data acquisition system

Science.gov (United States)

Ahmad, Farooq; Dennis, John Ojur; Md Khir, Mohd Haris; Hamid, Nor Hisham

2012-09-01

This paper presents the calibration of Helmholtz coils for the characterization of MEMS Magnetic sensor using Fluxgate magnetometer with DAS1 Magnetic Range Data Acquisition System. The Helmholtz coils arrangement is often used to generate a uniform magnetic field in space. In the past, standard magnets were used to calibrate the Helmholtz coils. A method is presented here for calibrating these coils using a Fluxgate magnetometer and known current source, which is easier and results in greater accuracy.

Implicit Boundary Integral Methods for the Helmholtz Equation in Exterior Domains

Science.gov (United States)

2016-06-01

solve the Helmholtz equation as ∂Ω goes through significant change in its shape and topology — applications for which implicit representation of the...boundary-value problems for the wave equation and maxwell’s equations. Russian Math . Surv., 1965. [16] S. Reutskiy. The method of fundamental

Kelvin-Helmholtz instability in a weakly ionized layer

OpenAIRE

Shadmehri, Mohsen; Downes, Turlough P.

2007-01-01

We study the linear theory of Kelvin-Helmholtz instability in a layer of ions and neutrals with finite thickness. In the short wavelength limit the thickness of the layer has a negligible effect on the growing modes. However, perturbations with wavelength comparable to layer's thickness are significantly affected by the thickness of the layer. We show that the thickness of the layer has a stabilizing effect on the two dominant growing modes. Transition between the modes not only depends on th...

Semi-analytic solution to planar Helmholtz equation

Directory of Open Access Journals (Sweden)

Tukač M.

2013-06-01

Full Text Available Acoustic solution of interior domains is of great interest. Solving acoustic pressure fields faster with lower computational requirements is demanded. A novel solution technique based on the analytic solution to the Helmholtz equation in rectangular domain is presented. This semi-analytic solution is compared with the finite element method, which is taken as the reference. Results show that presented method is as precise as the finite element method. As the semi-analytic method doesn’t require spatial discretization, it can be used for small and very large acoustic problems with the same computational costs.

Sensitivity Filters In Topology Optimisation As A Solution To Helmholtz Type Differential Equation

DEFF Research Database (Denmark)

Lazarov, Boyan Stefanov; Sigmund, Ole

2009-01-01

The focus of the study in this article is on the use of a Helmholtz type differential equation as a filter for topology optimisation problems. Until now various filtering schemes have been utilised in order to impose mesh independence in this type of problems. The usual techniques require topology...... information about the neighbour sub-domains is an expensive operation. The proposed filtering technique requires only mesh information necessary for the finite element discretisation of the problem. The main idea is to define the filtered variable implicitly as a solution of a Helmholtz type differential...... equation with homogeneous Neumann boundary conditions. The properties of the filter are demonstrated for various 2D and 3D topology optimisation problems in linear elasticity, solved on sequential and parallel computers....

[Scientific theoretical founding of medicine as a natural science by Hermann von Helmholtz (1821-1894)].

Science.gov (United States)

Neumann, J N

1994-01-01

In this study an attempt will be made to discuss the epistemological problems in the theory and practice of modern technical medicine in the writings of Hermann von Helmholz. An inquiry into the relationship between von Helmholtz' thinking and the critical philosophy of Immanuel Kant is followed by the characteristics of von Helmholtz' philosophy of science which he himself called "empirical theory". The question of medicine as a science finally leads to the main problem of medical epistemology, viz., the relationship between theoretical knowledge and practice in medicine. In this context the anthropological dimension is brought into consideration.

Installation of a technological center for highly efficient optical gratings at Helmholtz-Zentrum Berlin (HZB)

International Nuclear Information System (INIS)

Loechel, B; Erko, A; Lemke, St; Senf, F; Nelles, B; Schmidt, M

2013-01-01

In 2009 Carl Zeiss stopped the manufacture of precision gratings. All users of their gratings were very concerned about this decision, since they all need precision gratings for their experiments. One of the institutes of the HZB, the Institute for Nanometer Optics and Technology (INT), has extensive experience in micro fabrication (technology group). In spring 2010, HZB decided to take over the old C. Zeiss grating fabrication and build up its own technology center for grating fabrication. In March 2010, the INT applied to the Senate of Berlin for funding for our project from the European Regional Development Fund (ERDF). In October 2010, HZB received an approval of its application from the Senate of Berlin (contract No 20072013 2/43). Using this governmental support, HZB will install all necessary equipment and processes to fulfill these demands until end of 2013.

Collisionless Kelvin-Helmholtz instability and vortex-induced reconnection in the external region of the Earth magnetotail

International Nuclear Information System (INIS)

Pegoraro, F; Faganello, M; Califano, F

2008-01-01

In a magnetized plasma streaming with a non uniform velocity, the Kelvin-Helmholtz instability plays a major role in mixing different plasma regions and in stretching the magnetic field lines leading to the formation of layers with a sheared magnetic field where magnetic field line reconnection can take place. A relevant example is provided by the formation of a mixing layer between the Earth's magnetosphere and the solar wind at low latitudes during northward periods. In the considered configuration, in the presence of a magnetic field nearly perpendicular to the plane defined by the velocity field and its inhomogeneity direction, velocity shear drives a Kelvin-Helmholtz instability which advects and distorts the magnetic field configuration. If the Alfven velocity associated to the in-plane magnetic field is sufficiently weak with respect to the variation of the fluid velocity in the plasma, the Kelvin-Helmholtz instability generates fully rolled-up vortices which advect the magnetic field lines into a complex configuration, causing the formation of current layers along the inversion curves of the in-plane magnetic field component. Pairing of the vortices generated by the Kelvin-Helmholtz instability is a well know phenomenon in two-dimensional hydrodynamics. Here we investigate the development of magnetic reconnection during the vortex pairing process and show that completely different magnetic structures are produced depending on how fast the reconnection process develops on the time scale set by the pairing process.

Helmholtz and Diffusion Equations Associated with Local Fractional Derivative Operators Involving the Cantorian and Cantor-Type Cylindrical Coordinates

Directory of Open Access Journals (Sweden)

Ya-Juan Hao

2013-01-01

Full Text Available The main object of this paper is to investigate the Helmholtz and diffusion equations on the Cantor sets involving local fractional derivative operators. The Cantor-type cylindrical-coordinate method is applied to handle the corresponding local fractional differential equations. Two illustrative examples for the Helmholtz and diffusion equations on the Cantor sets are shown by making use of the Cantorian and Cantor-type cylindrical coordinates.

Effect of plasma density profile of tokamak on Kelvin-Helmholtz instability

International Nuclear Information System (INIS)

Tang Fulin

1984-01-01

The purpose of this paper is to study the effect of radial distribution of plasma density profile of tokamak on Kelvin-Helmholtz instability caused by toroidal rotation. The effect of radial distribution of plasma rotational velocity on stability is also examine for comparison. It is found that within the range of tokamak parameters the only radial distribution of plasma rotational velocity cannot induce Kelvin-Helmholtz instability. On the contrary, when there is a radial distribution of plasma density, i.e. P 01 =P 0 e -tx and V 0 1 = const, plasma becomes unstable, and instability will increase proportionally to the value of t. Meanwhile when the value of t remains constant, the instability growth rate will decrease if P 0 grows or the distance between plasma and wall of container decreases too. It shows that the Kelvin-Helmoltz instability is not only influenced by the steepness of density profile but also by the inertia of plasma in central region, which is helpful for depressing the instability. (author). 5 refs, 4 figs, 2 tabs

A low frequency acoustic insulator by using the acoustic metasurface to a Helmholtz resonator

Science.gov (United States)

Zhao, Xiang; Cai, Li; Yu, Dianlong; Lu, Zhimiao; Wen, Jihong

2017-06-01

Acoustic metasurfaces (AMSs) are able to manipulate wavefronts at an anomalous angle through a subwavelength layer. Their application provide a new way to control sound waves in addition to traditional materials. In this work, we introduced the AMS into the design of a Helmholtz resonator (HR) and studied the acoustic transmission through the modified HR in a pipe with one branch. The variation of sound insulation capacity with the phase gradient of the AMS was studied, and the results show that the AMS can remarkably lower the frequency band of the sound insulation without increasing the size. Our investigation provides a new degree of freedom for acoustic control with a Helmholtz resonator, which is of great significance in acoustic metasurface theory and sound insulation design.

The Common Data Acquisition Platform in the Helmholtz Association

International Nuclear Information System (INIS)

Kaever, P.; Balzer, M.; Kopmann, A.; Zimmer, M.; Rongen, H.

2017-01-01

Various centres of the German Helmholtz Association (HGF) started in 2012 to develop a modular data acquisition (DAQ) platform, covering the entire range from detector readout to data transfer into parallel computing environments. This platform integrates generic hardware components like the multi-purpose HGF-Advanced Mezzanine Card or a smart scientific camera framework, adding user value with Linux drivers and board support packages. Technically the scope comprises the DAQ-chain from FPGA-modules to computing servers, notably frontend-electronics-interfaces, microcontrollers and GPUs with their software plus high-performance data transmission links. The core idea is a generic and component-based approach, enabling the implementation of specific experiment requirements with low effort. This so called DTS-platform will support standards like MTCA.4 in hard- and software to ensure compatibility with commercial components. Its capability to deploy on other crate standards or FPGA-boards with PCI express or Ethernet interfaces remains an essential feature. Competences of the participating centres are coordinated in order to provide a solid technological basis for both research topics in the Helmholtz Programme ''Matter and Technology'': ''Detector Technology and Systems'' and ''Accelerator Research and Development''. The DTS-platform aims at reducing costs and development time and will ensure access to latest technologies for the collaboration. Due to its flexible approach, it has the potential to be applied in other scientific programs.

The Common Data Acquisition Platform in the Helmholtz Association

Science.gov (United States)

Kaever, P.; Balzer, M.; Kopmann, A.; Zimmer, M.; Rongen, H.

2017-04-01

Various centres of the German Helmholtz Association (HGF) started in 2012 to develop a modular data acquisition (DAQ) platform, covering the entire range from detector readout to data transfer into parallel computing environments. This platform integrates generic hardware components like the multi-purpose HGF-Advanced Mezzanine Card or a smart scientific camera framework, adding user value with Linux drivers and board support packages. Technically the scope comprises the DAQ-chain from FPGA-modules to computing servers, notably frontend-electronics-interfaces, microcontrollers and GPUs with their software plus high-performance data transmission links. The core idea is a generic and component-based approach, enabling the implementation of specific experiment requirements with low effort. This so called DTS-platform will support standards like MTCA.4 in hard- and software to ensure compatibility with commercial components. Its capability to deploy on other crate standards or FPGA-boards with PCI express or Ethernet interfaces remains an essential feature. Competences of the participating centres are coordinated in order to provide a solid technological basis for both research topics in the Helmholtz Programme ``Matter and Technology'': ``Detector Technology and Systems'' and ``Accelerator Research and Development''. The DTS-platform aims at reducing costs and development time and will ensure access to latest technologies for the collaboration. Due to its flexible approach, it has the potential to be applied in other scientific programs.

Combined Helmholtz Integral Equation - Fourier series formulation of acoustical radiation and scattering problems

CSIR Research Space (South Africa)

Fedotov, I

2006-07-01

Full Text Available The Combined Helmholtz Integral Equation – Fourier series Formulation (CHIEFF) is based on representation of a velocity potential in terms of Fourier series and finding the Fourier coefficients of this expansion. The solution could be substantially...

Calculation of the beam injector steering system using Helmholtz coils

International Nuclear Information System (INIS)

Passaro, A.; Sircilli Neto, F.; Migliano, A.C.C.

1991-03-01

In this work, a preliminary evaluation of the beam injector steering system of the IEAv electron linac is presented. From the existing injector configuration and with the assumptions of monoenergetic beam (100 keV) and uniform magnetic field, two pairs of Helmholtz coils were calculated for the steering system. Excitations of 105 A.turn and 37 A.turn were determined for the first and second coils, respectively. (author)

Layout and first results of the nanotomography endstation at the P05 beamline at PETRA III

Energy Technology Data Exchange (ETDEWEB)

Ogurreck, M.; Greving, I.; Beckmann, F.; Wilde, F.; Müller, M. [Institute of Materials Research, Helmholtz–Zentrum Geesthacht (Germany); Marschall, F.; Vogt, H.; Last, A. [Institute of Microstructure Technology, Karlsruhe Institute of Technology (Germany); Rosario, J. J. do [Institute of Advanced Ceramics, Technical University Hamburg–Harburg (Germany); Leib, E. W. [Institute of Physical Chemistry, University of Hamburg (Germany)

2016-01-28

The Helmholtz-Zentrum Geesthacht operates the P05 Imaging Beamline at the DESY storage ring PETRA III. This beamline is dedicated to micro- and nanotomography with two endstations. This paper will present the nanotomography endstation layout and first results obtained from commissioning and test experiments. First tests have been performed with CRLs as X-ray objectives and newly developed rolled X-ray prism lenses as condenser optics. This setup allows a resolution of 100 nm half period with an effective detector pixel size of 15nm. A first tomograph of a photonic glass sample was measured in early 2014.

ELBE Center for High-Power Radiation Sources

Directory of Open Access Journals (Sweden)

Peter Dr. Michel

2016-01-01

Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

Surface modifications of silica nanoparticles are crucial for their inert versus proinflammatory and immunomodulatory properties

Directory of Open Access Journals (Sweden)

Marzaioli V

2014-06-01

Full Text Available Viviana Marzaioli,1 Juan Antonio Aguilar-Pimente,1,2 Ingrid Weichenmeier,1 Georg Luxenhofer,3 Martin Wiemann,4 Robert Landsiedel,5 Wendel Wohlleben,5 Stefanie Eiden,6 Martin Mempel,7 Heidrun Behrendt,1 Carsten Schmidt-Weber,1 Jan Gutermuth,1,8 Francesca Alessandrini1 1Center of Allergy and Environment (ZAUM, Technische Universität and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL, Munich, Germany; 2Department of Dermatology and Allergy Biederstein, Technische Universität München (TUM and German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany, 3Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany; 4IBE R&D gGmbH, Münster, Germany; 5BASF, Ludwigshafen, Germany; 6Bayer Technology Services, Leverkusen, Germany; 7Department of Dermatology, Venereology and Allergology, Universitätsmedizin Göttingen (UMG, Göttingen, Germany; 8Department of Dermatology, Vrije Universiteit Brussel, Brussels, Belgium Background: Silica (SiO2 nanoparticles (NPs are widely used in diverse industrial and biomedical applications. Their applicability depends on surface modifications, which can limit potential health problems. Objective: To assess the potential impact of SiO2 NP exposure and NPs chemical modifications in allergic airway inflammation. Methods: Mice were sensitized by five repetitive intraperitoneal injections of ovalbumin/aluminum hydroxide (1 µg over 42 days, then intratracheally instilled with plain or modified SiO2 NPs (50 µg/mouse, and subsequently aerosol challenged for 20 minutes with ovalbumin. One or 5 days later, allergic inflammation was evaluated by cell differentiation of bronchoalveolar lavage fluid, lung function and gene expression and histopathology, as well as electron and confocal microscopy of pulmonary tissue. Results: Plain SiO2 NPs induced proinflammatory and immunomodulatory effects in vivo

Introduction of a new dosimetry system based on optically stimulated luminescence (OSL) in our personal monitoring service

International Nuclear Information System (INIS)

Hubner, S.

2014-08-01

The personal monitoring service named Auswertungsstelle is part of the Helmholtz Zentrum Munchen, a non-profit-making research center in Germany. As one of the four monitoring services in Germany, we have been a reliable partner in radiation protection for more than 60 years. With about 1.9 million dose assessments per year, we are the largest monitoring service in Europe. For dozens of years, our main dosimeter used in whole-body dosimetry has been a film dosimeter. Although its dosimetric properties are still up to date, film dosimetry won.t be a sustainable technique for the use in monitoring services. Therefore, a project with the objective of investigating alternative dosimetric materials and methods was launched in the late 1990 at the Helmholtz Zentrum Munchen. Based on this research work, the use of Be O as an OSL dosimeter was studied by the radiation physics group of the Tu Dresden, by order and on account of the Auswertungsstelle at the Helmholtz Zentrum Munchen. It was shown, that ceramic Be O features promising dosimetric properties, making Be O detectors particularly suitable for being used in all applications in whole-body dosimetry measuring photons. Ceramic Be O material has an excellent resistance to environmental influences. The Be O chips are almost tissue equivalent. Therefore, these detectors show low photon energy dependence. A new personal dosimetry system based on the OSL dosimetry of Be O was developed. Applying this system, the Auswertungsstelle offers OSL-dosimeters for official monitoring of the Personal Dose Equivalent Hp(10) since 2011. This OSL-System is accredited according to DIN IEC 62387 and we obtained the corresponding type approval by the Ptb, the national metrology institute in Germany. Sophisticated logistics was developed and installed. High degree of automation was achieved by robots for dosimeter assembly and machines for packing, labelling and unpacking of the dosimeters. To become a sustainable dosimetry system not only

Introduction of a new dosimetry system based on optically stimulated luminescence (OSL) in our personal monitoring service

Energy Technology Data Exchange (ETDEWEB)

Hubner, S., E-mail: stephan.huebner@helmholtz-muenchen.de [Helmholtz Zentrum Munchen, German Research Center for Environmental Health, D-80219, Munich (Georgia)

2014-08-15

The personal monitoring service named Auswertungsstelle is part of the Helmholtz Zentrum Munchen, a non-profit-making research center in Germany. As one of the four monitoring services in Germany, we have been a reliable partner in radiation protection for more than 60 years. With about 1.9 million dose assessments per year, we are the largest monitoring service in Europe. For dozens of years, our main dosimeter used in whole-body dosimetry has been a film dosimeter. Although its dosimetric properties are still up to date, film dosimetry won.t be a sustainable technique for the use in monitoring services. Therefore, a project with the objective of investigating alternative dosimetric materials and methods was launched in the late 1990 at the Helmholtz Zentrum Munchen. Based on this research work, the use of Be O as an OSL dosimeter was studied by the radiation physics group of the Tu Dresden, by order and on account of the Auswertungsstelle at the Helmholtz Zentrum Munchen. It was shown, that ceramic Be O features promising dosimetric properties, making Be O detectors particularly suitable for being used in all applications in whole-body dosimetry measuring photons. Ceramic Be O material has an excellent resistance to environmental influences. The Be O chips are almost tissue equivalent. Therefore, these detectors show low photon energy dependence. A new personal dosimetry system based on the OSL dosimetry of Be O was developed. Applying this system, the Auswertungsstelle offers OSL-dosimeters for official monitoring of the Personal Dose Equivalent Hp(10) since 2011. This OSL-System is accredited according to DIN IEC 62387 and we obtained the corresponding type approval by the Ptb, the national metrology institute in Germany. Sophisticated logistics was developed and installed. High degree of automation was achieved by robots for dosimeter assembly and machines for packing, labelling and unpacking of the dosimeters. To become a sustainable dosimetry system not only

Black and gray Helmholtz-Kerr soliton refraction

International Nuclear Information System (INIS)

Sanchez-Curto, Julio; Chamorro-Posada, Pedro; McDonald, Graham S.

2011-01-01

Refraction of black and gray solitons at boundaries separating different defocusing Kerr media is analyzed within a Helmholtz framework. A universal nonlinear Snell's law is derived that describes gray soliton refraction, in addition to capturing the behavior of bright and black Kerr solitons at interfaces. Key regimes, defined by beam and interface characteristics, are identified, and predictions are verified by full numerical simulations. The existence of a unique total nonrefraction angle for gray solitons is reported; both internal and external refraction at a single interface is shown possible (dependent only on incidence angle). This, in turn, leads to the proposal of positive or negative lensing operations on soliton arrays at planar boundaries.

A low frequency acoustic insulator by using the acoustic metasurface to a Helmholtz resonator

Directory of Open Access Journals (Sweden)

Xiang Zhao

2017-06-01

Full Text Available Acoustic metasurfaces (AMSs are able to manipulate wavefronts at an anomalous angle through a subwavelength layer. Their application provide a new way to control sound waves in addition to traditional materials. In this work, we introduced the AMS into the design of a Helmholtz resonator (HR and studied the acoustic transmission through the modified HR in a pipe with one branch. The variation of sound insulation capacity with the phase gradient of the AMS was studied, and the results show that the AMS can remarkably lower the frequency band of the sound insulation without increasing the size. Our investigation provides a new degree of freedom for acoustic control with a Helmholtz resonator, which is of great significance in acoustic metasurface theory and sound insulation design.

CFD simulation of Kelvin-Helmholtz instability

International Nuclear Information System (INIS)

Strubelj, L.; Tiselj, I.

2005-01-01

Kelvin-Helmholtz instability appears in stratified two-fluid flow at surface. When the relative velocity is higher than the critical relative velocity, the growth of waves occurs. The experiment of Thorpe [1] used as a benchmark in the present paper, is made in a rectangular glass tube filled with two immiscible fluids of various densities. We simulated the growth of instability with CFX-5.7 code and compared simulation with analytical solution. It was found that surface tension force, which stabilizes growth of waves, actually has a destabilizing effect in simulation, unless very small timestep and residual is used. In CFX code system of nonlinear Navier-Stokes equations is linearised and solved iterative in each timestep, until prescribed residual is achieved. On the other hand, simulation without surface tension force is more stable than analytical result predicts. (author)

A Third Note: Helmholtz, Palestrina, and the Early History of Musicology.

Science.gov (United States)

Kursell, Julia

2015-06-01

This contribution focuses on Hermann von Helmholtz's work on Renaissance composer Giovanni Pierluigi da Palestrina. Helmholtz used his scientific concept of distortion to analyze this music and, reversely, to find corroboration for the concept in his musical analyses. In this, his work interlocked with nineteenth-century aesthetic and scholarly ideals. His eagerness to use the latest products of historical scholarship in early music reveals a specific view of music history. Historical documents of music provide the opportunity for the discovery of new experimental research topics and thereby also reveal insights into hearing under different conditions. The essay argues that this work occupies a peculiar position in the history of musicology; it falls under the header of "systematic musicology," which eventually emerged as a discipline of musicology at the end of the nineteenth century. That this discipline has a history at all is easily overlooked, as many of its contributors were scientists with an interest in music. A history of musicology therefore must consider at least the following two caveats: parts of it take place outside the institutionalized field of musicology, and any history of musicology must, in the last instance, be embedded in a history of music.

Reconstruction of extended sources for the Helmholtz equation

International Nuclear Information System (INIS)

Kress, Rainer; Rundell, William

2013-01-01

The basis of most imaging methods is to detect hidden obstacles or inclusions within a body when one can only make measurements on an exterior surface. Our underlying model is that of inverse acoustic scattering based on the Helmholtz equation. Our inclusions are interior forces with compact support and our data consist of a single measurement of near-field Cauchy data on the external boundary. We propose an algorithm that under certain assumptions allows for the determination of the support set of these forces by solving a simpler ‘equivalent point source’ problem, and which uses a Newton scheme to improve the corresponding initial approximation. (paper)

Reconstruction of extended sources for the Helmholtz equation

KAUST Repository

Kress, Rainer

2013-02-26

The basis of most imaging methods is to detect hidden obstacles or inclusions within a body when one can only make measurements on an exterior surface. Our underlying model is that of inverse acoustic scattering based on the Helmholtz equation. Our inclusions are interior forces with compact support and our data consist of a single measurement of near-field Cauchy data on the external boundary. We propose an algorithm that under certain assumptions allows for the determination of the support set of these forces by solving a simpler \\'equivalent point source\\' problem, and which uses a Newton scheme to improve the corresponding initial approximation. © 2013 IOP Publishing Ltd.

Helmholtz and Goethe -- controversies at the birth of modern neuroscience.

Science.gov (United States)

Kesselring, Jürg

2013-01-01

Hermann von Helmholtz (1821-1894), a great German scientist and philosopher, made his mark during the exciting twilight period from the Enlightenment and Romanticism to the beginnings of modern neuroscience and offered new perspectives through his work. His early inclination was for physics, which he found more attractive than purely geometric and algebraic studies, but his father was not able to make it possible for him to study physics, and so he studied medicine in order to earn a living. His lecture before the Physical Society in Berlin on July 23, 1847, 'about the conservation of the force' marked an epochal turn, even though his intention had been to deliver 'merely, some critical investigations and arrangement of facts in favor of the physiologists' as well as good arguments for the refusal of the theory of 'vitality'. Even though these new concepts were at first dismissed as fantastic speculation by some of the authorities in physics and philosophy of the day, they were enthusiastically welcomed by younger students of philosophy and the older men soon had to allow themselves to be persuaded that the effectiveness of vitality, though great and beautiful, is actually always dependent on some source of energy. Helmholtz critically assessed Goethe as a physical scientist but he did not dispute his great importance as a poet. Copyright © 2012 S. Karger AG, Basel.

Archive of Geosample Information from the GEOMAR Helmholtz Centre for Ocean Research Kiel Core Repository

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The GEOMAR Helmholtz Centre for Ocean Research Kiel made a one-time contribution to the Index to Marine and Lacustrine Geological Samples (IMLGS) database of...

Density-space potential phase difference in a Kelvin--Helmholtz instability

International Nuclear Information System (INIS)

Glowienka, J.C.; Jennings, W.C.; Hickok, R.L.

1974-01-01

The low-frequency instability found in a hollow cathode discharge in helium was studied using an ion beam probe as a primary diagnostic tool. Three aspects of the instability are discussed: the location and amplitude of the oscillation and its correlation with the shape of the space potential; the phase angle between density and space potential oscillations; and the comparison of the data with three known instability models: Kelvin--Helmholtz, Rayleigh--Taylor, and drift waves--for mode identification. (U.S.)

Data compilation and evaluation of U(IV) and U(VI) for thermodynamic reference database THEREDA

Energy Technology Data Exchange (ETDEWEB)

Richter, Anke; Bok, Frank; Brendler, Vinzenz

2015-07-01

THEREDA (Thermodynamic Reference Database) is a collaborative project, which has been addressed this challenge. The partners are Helmholtz-Zentrum Dresden-Rossendorf, Karlsruhe Institute of Technology (KIT-INE), Gesellschaft fuer Anlagen- und Reaktorsicherheit Braunschweig mbH (GRS), TU Bergakademie Freiberg (TUBAF) and AF-Consult Switzerland AG (Baden, Switzerland). The aim of the project is the establishment of a consistent and quality assured database for all safety relevant elements, temperature and pressure ranges, with its focus on saline systems. This implied the use of the Pitzer approach to compute activity coefficients suitable for such conditions. Data access is possible via commonly available internet browsers under the address http://www.thereda.de. One part of the project - the data collection and evaluation for uranium - was a task of the Helmholtz-Zentrum Dresden-Rossendorf. The aquatic chemistry and thermodynamics of U(VI) and U(IV) is of great importance for geochemical modelling in repository-relevant systems. The OECD/NEA Thermochemical Database (NEA TDB) compilation is the major source for thermodynamic data of the aqueous and solid uranium species, even though this data selection does not utilize the Pitzer model for the ionic strength effect correction. As a result of the very stringent quality demands, the NEA TDB is rather restrictive and therefore incomplete for extensive modelling calculations of real systems. Therefore, the THEREDA compilation includes additional thermodynamic data of solid secondary phases formed in the waste material, the backfill and the host rock, though falling into quality assessment (QA) categories of lower accuracy. The data review process prefers log K values from solubility experiments (if available) to those calculated from thermochemical data.

Data compilation and evaluation of U(IV) and U(VI) for thermodynamic reference database THEREDA

International Nuclear Information System (INIS)

Richter, Anke; Bok, Frank; Brendler, Vinzenz

2015-01-01

THEREDA (Thermodynamic Reference Database) is a collaborative project, which has been addressed this challenge. The partners are Helmholtz-Zentrum Dresden-Rossendorf, Karlsruhe Institute of Technology (KIT-INE), Gesellschaft fuer Anlagen- und Reaktorsicherheit Braunschweig mbH (GRS), TU Bergakademie Freiberg (TUBAF) and AF-Consult Switzerland AG (Baden, Switzerland). The aim of the project is the establishment of a consistent and quality assured database for all safety relevant elements, temperature and pressure ranges, with its focus on saline systems. This implied the use of the Pitzer approach to compute activity coefficients suitable for such conditions. Data access is possible via commonly available internet browsers under the address http://www.thereda.de. One part of the project - the data collection and evaluation for uranium - was a task of the Helmholtz-Zentrum Dresden-Rossendorf. The aquatic chemistry and thermodynamics of U(VI) and U(IV) is of great importance for geochemical modelling in repository-relevant systems. The OECD/NEA Thermochemical Database (NEA TDB) compilation is the major source for thermodynamic data of the aqueous and solid uranium species, even though this data selection does not utilize the Pitzer model for the ionic strength effect correction. As a result of the very stringent quality demands, the NEA TDB is rather restrictive and therefore incomplete for extensive modelling calculations of real systems. Therefore, the THEREDA compilation includes additional thermodynamic data of solid secondary phases formed in the waste material, the backfill and the host rock, though falling into quality assessment (QA) categories of lower accuracy. The data review process prefers log K values from solubility experiments (if available) to those calculated from thermochemical data.

Adapting TESLA technology for future cw light sources using HoBiCaT

Science.gov (United States)

Kugeler, O.; Neumann, A.; Anders, W.; Knobloch, J.

2010-07-01

The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw.

Deflection gating for time-resolved x-ray magnetic circular dichroism-photoemission electron microscopy using synchrotron radiation

Science.gov (United States)

Wiemann, C.; Kaiser, A. M.; Cramm, S.; Schneider, C. M.

2012-06-01

In this paper, we present a newly developed gating technique for a time-resolving photoemission microscope. The technique makes use of an electrostatic deflector within the microscope's electron optical system for fast switching between two electron-optical paths, one of which is used for imaging, while the other is blocked by an aperture stop. The system can be operated with a switching time of 20 ns and shows superior dark current rejection. We report on the application of this new gating technique to exploit the time structure in the injection bunch pattern of the synchrotron radiation source BESSY II at Helmholtz-Zentrum Berlin for time-resolved measurements in the picosecond regime.

New version of the reactor dynamics code DYN3D for Sodium cooled Fast Reactor analyses

Energy Technology Data Exchange (ETDEWEB)

Nikitin, Evgeny [Ecole Polytechnique Federale de Lausanne (Switzerland); Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany); Fridman, Emil; Bilodid, Yuri; Kliem, Soeren [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany)

2017-07-15

The reactor dynamics code DYN3D being developed at the Helmholtz-Zentrum Dresden-Rossendorf is currently under extension for Sodium cooled Fast Reactor analyses. This paper provides an overview on the new version of DYN3D to be used for SFR core calculations. The current article shortly describes the newly implemented thermal mechanical models, which can account for thermal expansion effects of the reactor core. Furthermore, the methodology used in Sodium cooled Fast Reactor analyses to generate homogenized few-group cross sections is summarized. The conducted and planned verification and validation studies are briefly presented. Related publications containing more detailed descriptions are outlined for the completeness of this overview.

The Use of Helmholtz Resonance for Measuring the Volume of Liquids and Solids

Directory of Open Access Journals (Sweden)

Clive E. Davies

2010-11-01

Full Text Available An experimental investigation was undertaken to ascertain the potential of using Helmholtz resonance for volume determination and the factors that may influence accuracy. The uses for a rapid non-interference volume measurement system range from agricultural produce and mineral sampling through to liquid fill measurements. By weighing the sample the density can also measured indirectly.

Characterizing permanent magnet blocks with Helmholtz coils

Science.gov (United States)

Carnegie, D. W.; Timpf, J.

1992-08-01

Most of the insertion devices to be installed at the Advanced Photon Source will utilize permanent magnets in their magnetic structures. The quality of the spectral output is sensitive to the errors in the field of the device which are related to variations in the magnetic properties of the individual blocks. The Advanced Photon Source will have a measurement facility to map the field in the completed insertion devices and equipment to test and modify the magnetic strength of the individual magnet blocks. One component of the facility, the Helmholtz coil permanent magnet block measurement system, has been assembled and tested. This system measures the total magnetic moment vector of a block with a precision better than 0.01% and a directional resolution of about 0.05°. The design and performance of the system will be presented.

A Weakly Nonlinear Model for Kelvin–Helmholtz Instability in Incompressible Fluids

International Nuclear Information System (INIS)

Li-Feng, Wang; Wen-Hua, Ye; Zheng-Feng, Fan; Chuang, Xue; Ying-Jun, Li

2009-01-01

A weakly nonlinear model is proposed for the Kelvin–Helmholtz instability in two-dimensional incompressible fluids by expanding the perturbation velocity potential to third order. The third-order harmonic generation effects of single-mode perturbation are analyzed, as well as the nonlinear correction to the exponential growth of the fundamental modulation. The weakly nonlinear results are supported by numerical simulations. Density and resonance effects exist in the development of mode coupling. (fundamental areas of phenomenology (including applications))

Development of a high-sensitivity and portable cell using Helmholtz resonance for noninvasive blood glucose-level measurement based on photoacoustic spectroscopy.

Science.gov (United States)

Tachibana, K; Okada, K; Kobayashi, R; Ishihara, Y

2016-08-01

We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume. First, the acoustic property of the small-sized Helmholtz-type resonant cell was evaluated by performing an experiment using a silicone rubber. As a result, the detection sensitivity of the small-sized Helmholtz-type resonant cell was approximately two times larger than that of the conventional straight-type resonant cell. In addition, the inside volume was approximately 30 times smaller. Second, the detection limits of glucose concentration were estimated by performing an experiment using glucose solutions. The experimental results showed that a glucose concentration of approximately 1% was detected by the small-sized Helmholtz-type resonant cell. Although these results on the sensitivity of blood glucose-level measurement are currently insufficient, they suggest that miniaturization of a resonance cell is effective in the application of noninvasive blood glucose-level measurement.

Effect of cold plasma on the Kelvin-Helmholtz instability

International Nuclear Information System (INIS)

Melander, B.G.

1978-01-01

The thesis studies the effect of a two-component plasma (hot and cold) on the shear driven Kelvin-Helmholtz instability. An ion distribution with a shear flow parallel to the ambient magnetic field and a density gradient parallel to the shear direction is used. Both the electrostatic and electromagnetic versions of the instability are studied in the limit of hydromagnetic frequencies. The dispersion relation is obtained in the electrostatic case by solving the Vlasov equation for the perturbed ion and electron densities and then using the quasineutrality condition. In the electromagnetic case the coupled Vlasov and Maxwell's equations are solved to obtain the dispersion relation

Preliminary analysis of resonance effect by Helmholtz-Schrödinger method

International Nuclear Information System (INIS)

Er-Yan, Yan; Fan-Bao, Meng; Hong-Ge, Ma; Chao-Yang, Chen

2010-01-01

The Helmholtz-Schrödinger method is employed to study the electric field standing wave caused by coupling through a simple slot. There is a good agreement between the numerical results and the resonant conditions presented by the Helmholtz—Schrödinger method. Thus, it can be used in similar cases where the amplitude of the electric field is the important quantity or eigenfunctions of the Schrödinger equation are needed for complicated quantum structures with hard wall boundary conditions. (general)

Reminder of Lagrange-Hamilton formalism and of the corpuscular optics invariants

International Nuclear Information System (INIS)

Griess, F.

1958-01-01

Hamiltonian formalism - Canonical transformations - Invariants of Liouville, Helmholtz-Lagrange, Busch, Stoermer and Lagrange - Synchrotron's Hamiltonian - Betatron oscillation damping. (author) [fr

Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research. Annual report 2010

International Nuclear Information System (INIS)

Borany, J. von; Fassbender, J.; Heera, V.; Helm, M.

2011-01-01

The following topics are dealt with: Carrier profiling of individual Si nanowires by scanning spreading resistance microscopy, observation of the intraexciton Autler-Townes effect in GaAs/AlGaAs semiconductor quantum wells, terahertz activated luminescence of trapped carriers in InGaAs/GaAs quantum dots, a microwave enhanced silicon light emitting pn-diode, on-chip superconductivity via gallium overdoping of silicon, sculpting nanoscale precipitation patterns in nanocomposite thin films via hyperthermal ion deposition, establishing the mechanism of thermally induced degradation of ZnO:Al electrical properties using synchrotron radiation, determination of the saturation magnetization of ion irradiated Py/Ta samples using polar magneto-optical Kerr effect and ferromagnetic resonance, the importance of hole concentration in establishing carrier-mediated ferromagnetism in Mn doped Ge, pyramidal pits created by single highly charged ions in BaF 2 single crystals, optical properties of silver nanowire arrays with 35 nm periodicity. (HSI)

Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research. Annual report 2010

Energy Technology Data Exchange (ETDEWEB)

Borany, J. von; Fassbender, J.; Heera, V.; Helm, M. (eds.)

2011-10-26

The following topics are dealt with: Carrier profiling of individual Si nanowires by scanning spreading resistance microscopy, observation of the intraexciton Autler-Townes effect in GaAs/AlGaAs semiconductor quantum wells, terahertz activated luminescence of trapped carriers in InGaAs/GaAs quantum dots, a microwave enhanced silicon light emitting pn-diode, on-chip superconductivity via gallium overdoping of silicon, sculpting nanoscale precipitation patterns in nanocomposite thin films via hyperthermal ion deposition, establishing the mechanism of thermally induced degradation of ZnO:Al electrical properties using synchrotron radiation, determination of the saturation magnetization of ion irradiated Py/Ta samples using polar magneto-optical Kerr effect and ferromagnetic resonance, the importance of hole concentration in establishing carrier-mediated ferromagnetism in Mn doped Ge, pyramidal pits created by single highly charged ions in BaF{sub 2} single crystals, optical properties of silver nanowire arrays with 35 nm periodicity. (HSI)

Application of He’s Variational Iteration Method to Nonlinear Helmholtz Equation and Fifth-Order KDV Equation

DEFF Research Database (Denmark)

Miansari, Mo; Miansari, Me; Barari, Amin

2009-01-01

In this article, He’s variational iteration method (VIM), is implemented to solve the linear Helmholtz partial differential equation and some nonlinear fifth-order Korteweg-de Vries (FKdV) partial differential equations with specified initial conditions. The initial approximations can be freely c...

The Kelvin-Helmholtz instability on the magnetopause

International Nuclear Information System (INIS)

Kivelson, M.G.; California Univ., Los Angeles; Pu, Z.-Y.

1984-01-01

Conditions for the development of Kelvin-Helmholtz (K-H) waves on the magnetopause have been known for more than 15 years; more recently, spacecraft observations have stimulated further examination of the properties of K-H waves. For a magnetopause with no boundary layer, two different modes of surface waves have been identified and their properties have been investigated for various assumed orientations of magnetic field and flow velocity vectors. The power radiated into the magnetosphere from the velocity shear at the boundary has been estimated. Other calculations have focused on the consequences of finite thickness boundary layers, both uniform and non-uniform. The boundary layer is found to modify the wave modes present at the magnetopause and to yield a criterion for the wavelength of the fastest growing surface waves. The paper concludes by questioning the extent to which the inferences from boundary layer models are model dependent and identifies areas where further work is needed or anticipated. (author)

On the major DYN3D developments for fast reactor design and transient analysis

International Nuclear Information System (INIS)

Merk, B.; Kliem, S.

2013-01-01

Due to the French project ASTRID, the European CP-ESFR project, and the MYRRHA/FASTEF project, the research work on fast reactors has got a new push in Europe. Additionally to this European projects a strong project is growing in Russia based on the lead cooled fast reactor design BREST. Following this trend, the Institute of Resource Ecology at the Helmholtz-Zentrum Dresden-Rossendorf has decided to start several projects dedicated to fast reactor technology, among them the extension of the well validated LWR core simulator DYN3D. The new developments, first validation results, and the next strategic steps for the adaption of the code for the improved simulation of fast reactor cores are presented. (orig.)

On the major DYN3D developments for fast reactor design and transient analysis

Energy Technology Data Exchange (ETDEWEB)

Merk, B.; Kliem, S. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactor Safety Div.

2013-07-01

Due to the French project ASTRID, the European CP-ESFR project, and the MYRRHA/FASTEF project, the research work on fast reactors has got a new push in Europe. Additionally to this European projects a strong project is growing in Russia based on the lead cooled fast reactor design BREST. Following this trend, the Institute of Resource Ecology at the Helmholtz-Zentrum Dresden-Rossendorf has decided to start several projects dedicated to fast reactor technology, among them the extension of the well validated LWR core simulator DYN3D. The new developments, first validation results, and the next strategic steps for the adaption of the code for the improved simulation of fast reactor cores are presented. (orig.)

Micro-CT at the imaging beamline P05 at PETRA III

International Nuclear Information System (INIS)

Wilde, Fabian; Ogurreck, Malte; Greving, Imke; Hammel, Jörg U.; Beckmann, Felix; Hipp, Alexander; Lottermoser, Lars; Khokhriakov, Igor; Lytaev, Pavel; Dose, Thomas; Burmester, Hilmar; Müller, Martin; Schreyer, Andreas

2016-01-01

The Imaging Beamline (IBL) P05 is operated by the Helmholtz-Zentrum Geesthacht and located at the DESY storage ring PETRA III. IBL is dedicated to X-ray full field imaging and consists of two experimental end stations. A micro tomography end station equipped for spatial resolutions down to 1 µm and a nano tomography end station for spatial resolutions down to 100 nm. The micro tomography end station is in user operation since 2013 and offers imaging with absorption contrast, phase enhanced absorption contrast and phase contrast methods. We report here on the current status and developments of the micro tomography end station including technical descriptions and show examples of research performed at P05.

Equation of state and Helmholtz free energy for the atomic system of the repulsive Lennard-Jones particles.

Science.gov (United States)

Mirzaeinia, Ali; Feyzi, Farzaneh; Hashemianzadeh, Seyed Majid

2017-12-07

Simple and accurate expressions are presented for the equation of state (EOS) and absolute Helmholtz free energy of a system composed of simple atomic particles interacting through the repulsive Lennard-Jones potential model in the fluid and solid phases. The introduced EOS has 17 and 22 coefficients for fluid and solid phases, respectively, which are regressed to the Monte Carlo (MC) simulation data over the reduced temperature range of 0.6≤T * ≤6.0 and the packing fraction range of 0.1 ≤ η ≤ 0.72. The average absolute relative percent deviation in fitting the EOS parameters to the MC data is 0.06 and 0.14 for the fluid and solid phases, respectively. The thermodynamic integration method is used to calculate the free energy using the MC simulation results. The Helmholtz free energy of the ideal gas is employed as the reference state for the fluid phase. For the solid phase, the values of the free energy at the reduced density equivalent to the close-packed of a hard sphere are used as the reference state. To check the validity of the predicted values of the Helmholtz free energy, the Widom particle insertion method and the Einstein crystal technique of Frenkel and Ladd are employed. The results obtained from the MC simulation approaches are well agreed to the EOS results, which show that the proposed model can reliably be utilized in the framework of thermodynamic theories.

Connecting science and the musical arts in teaching tone quality: Integrating Helmholtz motion and master violin teachers' pedagogies

Science.gov (United States)

Collins, Cheri D.

Is it possible for students to achieve better tone quality from even their factory-made violins? All violins, regardless of cost, have a common capacity for good tone in certain frequencies. These signature modes outline the first position range of a violin (196-600 hertz). To activate this basic capacity of all violins, the string must fully vibrate. To accomplish this the bow must be pulled across the string with enough pressure (relative to its speed and contact point) for the horsehairs to catch. This friction permits the string to vibrate in Helmholtz Motion, which produces a corner that travels along the edge of the string between the bridge and the nut. Creating this corner is the most fundamental technique for achieving good tone. The findings of celebrated scientists Ernest Chladni, Hermann von Helmholtz, and John Schelleng will be discussed and the tone-production pedagogy of master teachers Carl Flesch, Ivan Galamian, Robert Gerle, and Simon Fischer will be investigated. Important connections between the insights of these scientists and master teachers are evident. Integrating science and art can provide teachers with a better understanding of the characteristics of good tone. This can help their students achieve the best possible sound from their instruments. In the private studio the master teacher may not use the words "Helmholtz Motion." Yet through modeling and listening students are able to understand and create a quality tone. Music teachers without experience in string performance may be assigned to teach strings in classroom and ensembles settings. As a result modeling good tone is not always possible. However, all teachers and conductors can understand the fundamental behavior of string vibration and adapt their instruction strategies towards student success. Better tonal quality for any string instrument is ultimately achieved. Mastery and use of the Helmholtz Motion benefits teachers and students alike. Simple practice exercises for teaching

Kelvin-Helmholtz instability for a bounded plasma flow in a longitudinal magnetic field

International Nuclear Information System (INIS)

Burinskaya, T. M.; Shevelev, M. M.; Rauch, J.-L.

2011-01-01

Kelvin-Helmholtz MHD instability in a plane three-layer plasma is investigated. A general dispersion relation for the case of arbitrarily orientated magnetic fields and flow velocities in the layers is derived, and its solutions for a bounded plasma flow in a longitudinal magnetic field are studied numerically. Analysis of Kelvin-Helmholtz instability for different ion acoustic velocities shows that perturbations with wavelengths on the order of or longer than the flow thickness can grow in an arbitrary direction even at a zero temperature. Oscillations excited at small angles with respect to the magnetic field exist in a limited range of wavenumbers even without allowance for the finite width of the transition region between the flow and the ambient plasma. It is shown that, in a low-temperature plasma, solutions resulting in kink-like deformations of the plasma flow grow at a higher rate than those resulting in quasi-symmetric (sausage-like) deformations. The transverse structure of oscillatory-damped eigenmodes in a low-temperature plasma is analyzed. The results obtained are used to explain mechanisms for the excitation of ultra-low-frequency long-wavelength oscillations propagating along the magnetic field in the plasma sheet boundary layer of the Earth’s magnetotail penetrated by fast plasma flows.

Iterative solution of the Helmholtz equation

Energy Technology Data Exchange (ETDEWEB)

Larsson, E.; Otto, K. [Uppsala Univ. (Sweden)

1996-12-31

We have shown that the numerical solution of the two-dimensional Helmholtz equation can be obtained in a very efficient way by using a preconditioned iterative method. We discretize the equation with second-order accurate finite difference operators and take special care to obtain non-reflecting boundary conditions. We solve the large, sparse system of equations that arises with the preconditioned restarted GMRES iteration. The preconditioner is of {open_quotes}fast Poisson type{close_quotes}, and is derived as a direct solver for a modified PDE problem.The arithmetic complexity for the preconditioner is O(n log{sub 2} n), where n is the number of grid points. As a test problem we use the propagation of sound waves in water in a duct with curved bottom. Numerical experiments show that the preconditioned iterative method is very efficient for this type of problem. The convergence rate does not decrease dramatically when the frequency increases. Compared to banded Gaussian elimination, which is a standard solution method for this type of problems, the iterative method shows significant gain in both storage requirement and arithmetic complexity. Furthermore, the relative gain increases when the frequency increases.

Of the Helmholtz Club, South-Californian seedbed for visual and cognitive neuroscience, and its patron Francis Crick.

Science.gov (United States)

Aicardi, Christine

2014-03-01

Taking up the view that semi-institutional gatherings such as clubs, societies, research schools, have been instrumental in creating sheltered spaces from which many a 20th-century project-driven interdisciplinary research programme could develop and become established within the institutions of science, the paper explores the history of one such gathering from its inception in the early 1980s into the 2000s, the Helmholtz Club, which brought together scientists from such various research fields as neuroanatomy, neurophysiology, psychophysics, computer science and engineering, who all had an interest in the study of the visual system and of higher cognitive functions relying on visual perception such as visual consciousness. It argues that British molecular biologist turned South Californian neuroscientist Francis Crick had an early and lasting influence over the Helmholtz Club of which he was a founding pillar, and that from its inception, the club served as a constitutive element in his long-term plans for a neuroscience of vision and of cognition. Further, it argues that in this role, the Helmholtz Club served many purposes, the primary of which was to be a social forum for interdisciplinary discussion, where 'discussion' was not mere talk but was imbued with an epistemic value and as such, carefully cultivated. Finally, it questions what counts as 'doing science' and in turn, definitions of success and failure-and provides some material evidence towards re-appraising the successfulness of Crick's contribution to the neurosciences. Copyright © 2013 The Author. Published by Elsevier Ltd.. All rights reserved.

Development of a Miniature, Two-Axis, Triple-Helmholtz-Driven Gimbal

Science.gov (United States)

Sharif, Boz; Joscelyn, Ed; Wilcox, Brian; Johnson, Michael R.

2000-01-01

This paper details the development of a Helmholtz-driven, 2-axis gimbal to position a flat mirror within 50 microradian (fine positioning) in a space environment. The gimbal is intended to travel on a deep space mission mounted on a miniature "rover" vehicle. The gimbal will perform both pointing and scanning functions. The goal for total mass of the gimbal was 25 grams. The primary challenge was to design and build a bearing system that would achieve the required accuracy in addition to supporting the relatively large mass of the mirror and the outer gimbal. The mechanism is subjected to 100-G loading without the aid of any additional caging mechanism. Additionally, it was desired to have the same level of accuracy during Earth-bound, 1-G testing. Due to the inherent lack of damping in a zero-G, vacuum environment; the ability of the gimbal to respond to very small amounts of input energy is paramount. Initial testing of the first prototype revealed exceedingly long damping times required even while exposed to the damping effects of air and 1-G friction. It is envisioned that fine positioning of the gimbal will be accomplished in very small steps to avoid large disturbances to the mirror. Various bearing designs, including materials, lubrication options and bearing geometry will be discussed. In addition various options for the Helmholtz coil design will be explored with specific test data given. Ground testing in the presence of 1-G was compounded by the local magnetic fields due to the "compass" effect on the gimbal. The test data will be presented and discussed. Additionally, rationale for estimating gimbal performance in a zero-G environment will be presented and discussed.

Numerical solution of an inverse 2D Cauchy problem connected with the Helmholtz equation

International Nuclear Information System (INIS)

Wei, T; Qin, H H; Shi, R

2008-01-01

In this paper, the Cauchy problem for the Helmholtz equation is investigated. By Green's formulation, the problem can be transformed into a moment problem. Then we propose a numerical algorithm for obtaining an approximate solution to the Neumann data on the unspecified boundary. Error estimate and convergence analysis have also been given. Finally, we present numerical results for several examples and show the effectiveness of the proposed method

Enhancing DC Glow Discharge Tube Museuum Displays using a Theremin Controlled Helmholtz Coil to Demonstrate Magnetic Confinement

Science.gov (United States)

Siu, Theodore; Wissel, Stephanie; Guttadora, Larry; Liao, Susan; Zwicker, Andrew

2010-11-01

Since their discovery in the mid 1800's, DC glow discharge apparatuses have commonly been used for spectral analysis, the demonstration of the Frank-Hertz experiment, and to study plasma breakdown voltages following from the Paschen Curve. A DC glow discharge tube museum display was outfitted with a Helmholtz Coil electromagnet in order to demonstrate magnetic confinement for a science museum display. A device commonly known as a ``theremin'' was designed and built in order to externally control the Helmholtz Coil current and the plasma current. Originally a musical instrument, a theremin has two variable capacitors connected to two radio frequency oscillators which determine pitch and volume. Using a theremin to control current and ``play'' the plasma adds appeal and durability by providing a new innovative means of interacting with a museum exhibit. Educationally, students can use the display to not only learn about plasma properties but also electronic properties of the human body.

Kelvin-Helmholtz instability: the ``atom'' of geophysical turbulence?

Science.gov (United States)

Smyth, William

2017-11-01

Observations of small-scale turbulence in Earth's atmosphere and oceans have most commonly been interpreted in terms of the Kolmogorov theory of isotropic turbulence, despite the fact that the observed turbulence is significantly anisotropic due to density stratification and sheared large-scale flows. I will describe an alternative picture in which turbulence consists of distinct events that occur sporadically in space and time. The simplest model for an individual event is the ``Kelvin-Helmholtz (KH) ansatz'', in which turbulence relieves the dynamic instability of a localized shear layer. I will summarize evidence that the KH ansatz is a valid description of observed turbulence events, using microstructure measurements from the equatorial Pacific ocean as an example. While the KH ansatz has been under study for many decades and is reasonably well understood, the bigger picture is much less clear. How are the KH events distributed in space and time? How do different events interact with each other? I will describe some tentative steps toward a more thorough understanding.

Integrability and symmetries for the Helmholtz oscillator with friction

International Nuclear Information System (INIS)

Almendral, Juan A; Sanjuan, Miguel A F

2003-01-01

This paper deals with the Helmholtz oscillator, which is a simple nonlinear oscillator whose equation presents a quadratic nonlinearity and the possibility of escape. When a periodic external force is introduced, the width of the stochastic layer, which is a region around the separatrix where orbits may exhibit transient chaos, is calculated. In the absence of friction and external force, it is well known that analytical solutions exist since it is completely integrable. When only friction is included, there is no analytical solution for all parameter values. However, by means of the Lie theory for differential equations we find a relation between parameters for which the oscillator is integrable. This is related to the fact that the system possesses a symmetry group and the corresponding symmetries are computed. Finally, the analytical explicit solutions are shown and related to the basins of attraction

Kelvin-Helmholtz instability and kinetic internal kink modes in tokamaks

International Nuclear Information System (INIS)

Naitou, H.

2002-01-01

The m=1 and n=1 kinetic internal kink (KIK) mode with a nonuniform density profile is studied by the cylindrical version of the gyro-reduced-MHD code which is one of the extended MHD codes being able to treat the physics beyond resistive MHD. Electron inertia and electron finite temperature effects are crucial. The linear mode structure of KIK mode includes the sheared poloidal flow with m=1, which excites the vortexes due to the Kelvin-Helmholtz (K-H) instability. We have found that there is a strong coupling between the KIK mode and the K-H mode even in the early nonlinear stage of KIK instability in which the width of the m=1 magnetic island is sufficiently small. (author)

Novel approach to the Helmholtz integral equation solution by Fourier series expansion for acoustic radiation and scattering problems

CSIR Research Space (South Africa)

Shatalov, MY

2006-01-01

Full Text Available -scale structure to guarantee the numerical accuracy of solution. In the present paper the authors propose to use a novel method of solution of the Helmholtz integral equation, which is based on expansion of the integrands in double Fourier series. The main...

On Riemann boundary value problems for null solutions of the two dimensional Helmholtz equation

Science.gov (United States)

Bory Reyes, Juan; Abreu Blaya, Ricardo; Rodríguez Dagnino, Ramón Martin; Kats, Boris Aleksandrovich

2018-01-01

The Riemann boundary value problem (RBVP to shorten notation) in the complex plane, for different classes of functions and curves, is still widely used in mathematical physics and engineering. For instance, in elasticity theory, hydro and aerodynamics, shell theory, quantum mechanics, theory of orthogonal polynomials, and so on. In this paper, we present an appropriate hyperholomorphic approach to the RBVP associated to the two dimensional Helmholtz equation in R^2 . Our analysis is based on a suitable operator calculus.

KELVIN-HELMHOLTZ INSTABILITY OF A CORONAL STREAMER

Energy Technology Data Exchange (ETDEWEB)

Feng, L.; Gan, W. Q. [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 210008 Nanjing (China); Inhester, B., E-mail: lfeng@pmo.ac.cn [Max-Planck-Institut fuer Sonnensystemforschung, Max-Planck-Str.2, D-37191 Katlenburg-Lindau (Germany)

2013-09-10

Shear-flow-driven instability can play an important role in energy transfer processes in coronal plasma. We present for the first time the observation of a kink-like oscillation of a streamer that is probably caused by the streaming kink-mode Kelvin-Helmholtz instability (KHI). The wave-like behavior of the streamer was observed by the Large Angle and Spectrometric Coronagraph Experiment C2 and C3 on board the SOlar and Heliospheric Observatory. The observed wave had a period of about 70-80 minutes, and its wavelength increased from 2 R{sub Sun} to 3 R{sub Sun} in about 1.5 hr. The phase speeds of its crests and troughs decreased from 406 {+-} 20 to 356 {+-} 31 km s{sup -1} during the event. Within the same heliocentric range, the wave amplitude also appeared to increase with time. We attribute the phenomena to the MHD KHI, which occurs at a neutral sheet in a fluid wake. The free energy driving the instability is supplied by the sheared flow and sheared magnetic field across the streamer plane. The plasma properties of the local environment of the streamer were estimated from the phase speed and instability threshold criteria.

Nonlinear evolution of the magnetized Kelvin-Helmholtz instability: From fluid to kinetic modeling

Czech Academy of Sciences Publication Activity Database

Henri, P.; Cerri, S.S.; Califano, F.; Pegoraro, F.; Rossi, C.; Faganello, M.; Šebek, Ondřej; Trávníček, Pavel M.; Hellinger, Petr; Frederiksen, J. T.; Nordlund, A.; Markidis, S.; Keppens, R.; Lapenta, G.

2013-01-01

Roč. 20, č. 10 (2013), 102118/1-102118/13 ISSN 1070-664X R&D Projects: GA MŠk(CZ) 7E11053 EU Projects: European Commission(XE) 263340 - SWIFF Grant - others:European Commission(XE) HPC-EUROPA2 - No. 228398; EU(XE) RI-283493; NASA (US) NNX11A1164G Institutional support: RVO:67985815 ; RVO:68378289 Keywords : Kelvin-Helmholtz instability * plasma kinetic theory * plasma magnetohydrodynamics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics; BL - Plasma and Gas Discharge Physics (UFA-U) Impact factor: 2.249, year: 2013

Applying the Helmholtz Illusion to Fashion: Horizontal Stripes Won't Make You Look Fatter

Directory of Open Access Journals (Sweden)

Peter Thompson

2011-01-01

Full Text Available A square composed of horizontal lines appears taller and narrower than an identical square made up of vertical lines. Reporting this illusion, Hermann von Helmholtz noted that such illusions, in which filled space seems to be larger than unfilled space, were common in everyday life, adding the observation that ladies' frocks with horizontal stripes make the figure look taller. As this assertion runs counter to modern popular belief, we have investigated whether vertical or horizontal stripes on clothing should make the wearer appear taller or fatter. We find that a rectangle of vertical stripes needs to be extended by 7.1% vertically to match the height of a square of horizontal stripes and that a rectangle of horizontal stripes must be made 4.5% wider than a square of vertical stripes to match its perceived width. This illusion holds when the horizontal or vertical lines are on the dress of a line drawing of a woman. We have examined the claim that these effects apply only for 2-dimensional figures in an experiment with 3-D cylinders and find no support for the notion that horizontal lines would be ‘fattening’ on clothes. Significantly, the illusion persists when the horizontal or vertical lines are on pictures of a real half-body mannequin viewed stereoscopically. All the evidence supports Helmholtz's original assertion.

A Parallel Sweeping Preconditioner for Heterogeneous 3D Helmholtz Equations

KAUST Repository

Poulson, Jack

2013-05-02

A parallelization of a sweeping preconditioner for three-dimensional Helmholtz equations without large cavities is introduced and benchmarked for several challenging velocity models. The setup and application costs of the sequential preconditioner are shown to be O(γ2N4/3) and O(γN logN), where γ(ω) denotes the modestly frequency-dependent number of grid points per perfectly matched layer. Several computational and memory improvements are introduced relative to using black-box sparse-direct solvers for the auxiliary problems, and competitive runtimes and iteration counts are reported for high-frequency problems distributed over thousands of cores. Two open-source packages are released along with this paper: Parallel Sweeping Preconditioner (PSP) and the underlying distributed multifrontal solver, Clique. © 2013 Society for Industrial and Applied Mathematics.

Acoustic response of Helmholtz dampers in the presence of hot grazing flow

Science.gov (United States)

Ćosić, B.; Wassmer, D.; Terhaar, S.; Paschereit, C. O.

2015-01-01

Thermoacoustic instabilities are high amplitude instabilities of premixed gas turbine combustors. Cooled passive dampers are used to attenuate or suppress these instabilities in the combustion chamber. For the first time, the influence of temperature differences between the grazing flow in the combustor and the cross-flow emanating from the Helmholtz damper is comprehensively investigated in the linear and nonlinear amplitude regime. The flow field inside the resonator and in the vicinity of the neck is measured with high-speed particle image velocimetry for various amplitudes and at different momentum-flux ratios of grazing and purging flow. Seeding is used as a tracer to qualitatively assess the mixing of the grazing and purging flow as well as the ingestion into the neck of the resonator. Experimentally, the acoustic response for various temperature differences between grazing and purging flow is investigated. The multi-microphone method, in combination with two microphones flush-mounted in the resonator volume and two microphones in the plane of the resonator entrance, is used to determine the impedance of the Helmholtz resonator in the linear and nonlinear amplitude regime for various temperatures and different momentum-flux ratios. Additionally, a thermocouple was used to measure the temperature in the neck. The acoustic response and the temperature measurements are used to obtain the virtual neck length and the effective area jump from a detailed impedance model. This model is extended to include the observed acoustic energy dissipation caused by the density gradients at the neck vicinity. A clear correlation between temperature differences and changes of the mass end-correction is confirmed. The capabilities of the impedance model are demonstrated.

Monolithically integrated Helmholtz coils by 3-dimensional printing

Energy Technology Data Exchange (ETDEWEB)

Li, Longguang [Department of Electrical Engineering, University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Abedini-Nassab, Roozbeh; Yellen, Benjamin B., E-mail: yellen@duke.edu [Department of Electrical Engineering, University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mechanical Engineering and Materials Science, Duke University, P.O. Box 90300, Hudson Hall, Durham, North Carolina 27708 (United States)

2014-06-23

3D printing technology is of great interest for the monolithic fabrication of integrated systems; however, it is a challenge to introduce metallic components into 3D printed molds to enable broader device functionality. Here, we develop a technique for constructing a multi-axial Helmholtz coil by injecting a eutectic liquid metal Gallium Indium alloy (EGaIn) into helically shaped orthogonal cavities constructed in a 3D printed block. The tri-axial solenoids each carry up to 3.6 A of electrical current and produce magnetic field up to 70 G. Within the central section of the coil, the field variation is less than 1% and is in agreement with theory. The flow rates and critical pressures required to fill the 3D cavities with liquid metal also agree with theoretical predictions and provide scaling trends for filling the 3D printed parts. These monolithically integrated solenoids may find future applications in electronic cell culture platforms, atomic traps, and miniaturized chemical analysis systems based on nuclear magnetic resonance.

Monolithically integrated Helmholtz coils by 3-dimensional printing

International Nuclear Information System (INIS)

Li, Longguang; Abedini-Nassab, Roozbeh; Yellen, Benjamin B.

2014-01-01

3D printing technology is of great interest for the monolithic fabrication of integrated systems; however, it is a challenge to introduce metallic components into 3D printed molds to enable broader device functionality. Here, we develop a technique for constructing a multi-axial Helmholtz coil by injecting a eutectic liquid metal Gallium Indium alloy (EGaIn) into helically shaped orthogonal cavities constructed in a 3D printed block. The tri-axial solenoids each carry up to 3.6 A of electrical current and produce magnetic field up to 70 G. Within the central section of the coil, the field variation is less than 1% and is in agreement with theory. The flow rates and critical pressures required to fill the 3D cavities with liquid metal also agree with theoretical predictions and provide scaling trends for filling the 3D printed parts. These monolithically integrated solenoids may find future applications in electronic cell culture platforms, atomic traps, and miniaturized chemical analysis systems based on nuclear magnetic resonance.

Kelvin-Helmholtz instability in a bounded plasma flow

International Nuclear Information System (INIS)

Burinskaya, T. M.

2008-01-01

Kelvin-Helmholtz instability in a three-layer plane geometry is investigated theoretically. It is shown that, in a three-layer system (in contrast to the traditionally considered case in which instability develops at the boundary between two plasma flows), instability can develop at an arbitrary ratio of the plasma flow velocity to the ion-acoustic velocity. Perturbations with wavelengths on the order of the flow thickness or longer can increase even at a zero temperature. The system can also be unstable against long-wavelength perturbations if the flow velocity at one of the boundaries is lower than the sum of the Alfven velocities in the flow and the ambient plasma. The possibility of applying the results obtained to interpret the experimental data acquired in the framework of the CLUSTER multisatellite project is discussed. It follows from these data that, in many cases, the propagation of an accelerated particle flow in the plasma-sheet boundary layer of the Earth's magnetotail is accompanied by the generation of magnetic field oscillations propagating with a velocity on the order of the local Alfven velocity.

ASTEM, Evaluation of Gibbs, Helmholtz and Saturation Line Function for Thermodynamics Calculation

International Nuclear Information System (INIS)

Moore, K.V.; Burgess, M.P.; Fuller, G.L.; Kaiser, A.H.; Jaeger, D.L.

1974-01-01

1 - Description of problem or function: ASTEM is a modular set of FORTRAN IV subroutines to evaluate the Gibbs, Helmholtz, and saturation line functions as published by the American Society of Mechanical Engineers (1967). Any thermodynamic quantity including derivative properties can be obtained from these routines by a user-supplied main program. PROPS is an auxiliary routine available for the IBM360 version which makes it easier to apply the ASTEM routines to power station models. 2 - Restrictions on the complexity of the problem: Unless re-dimensioned by the user, the highest derivative allowed is order 9. All arrays within ASTEM are one-dimensional to save storage area

Numerical investigation on an array of Helmholtz resonators for the reduction of micro-pressure waves in modern and future high-speed rail tunnel systems

Science.gov (United States)

Tebbutt, J. A.; Vahdati, M.; Carolan, D.; Dear, J. P.

2017-07-01

Previous research has proposed that an array of Helmholtz resonators may be an effective method for suppressing the propagation of pressure and sound waves, generated by a high-speed train entering and moving in a tunnel. The array can be used to counteract environmental noise from tunnel portals and also the emergence of a shock wave in the tunnel. The implementation of an array of Helmholtz resonators in current and future high-speed train-tunnel systems is studied. Wave propagation in the tunnel is modelled using a quasi-one-dimensional formulation, accounting for non-linear effects, wall friction and the diffusivity of sound. A multi-objective genetic algorithm is then used to optimise the design of the array, subject to the geometric constraints of a demonstrative tunnel system and the incident wavefront in order to attenuate the propagation of pressure waves. It is shown that an array of Helmholtz resonators can be an effective countermeasure for various tunnel lengths. In addition, the array can be designed to function effectively over a wide operating envelope, ensuring it will still function effectively as train speeds increase into the future.

A comparison of high-order polynomial and wave-based methods for Helmholtz problems

Science.gov (United States)

Lieu, Alice; Gabard, Gwénaël; Bériot, Hadrien

2016-09-01

The application of computational modelling to wave propagation problems is hindered by the dispersion error introduced by the discretisation. Two common strategies to address this issue are to use high-order polynomial shape functions (e.g. hp-FEM), or to use physics-based, or Trefftz, methods where the shape functions are local solutions of the problem (typically plane waves). Both strategies have been actively developed over the past decades and both have demonstrated their benefits compared to conventional finite-element methods, but they have yet to be compared. In this paper a high-order polynomial method (p-FEM with Lobatto polynomials) and the wave-based discontinuous Galerkin method are compared for two-dimensional Helmholtz problems. A number of different benchmark problems are used to perform a detailed and systematic assessment of the relative merits of these two methods in terms of interpolation properties, performance and conditioning. It is generally assumed that a wave-based method naturally provides better accuracy compared to polynomial methods since the plane waves or Bessel functions used in these methods are exact solutions of the Helmholtz equation. Results indicate that this expectation does not necessarily translate into a clear benefit, and that the differences in performance, accuracy and conditioning are more nuanced than generally assumed. The high-order polynomial method can in fact deliver comparable, and in some cases superior, performance compared to the wave-based DGM. In addition to benchmarking the intrinsic computational performance of these methods, a number of practical issues associated with realistic applications are also discussed.

Chlorine measurements at the 5MV French AMS national facility ASTER: Associated external uncertainties and comparability with the 6MV DREAMS facility

Science.gov (United States)

Braucher, R.; Keddadouche, K.; Aumaître, G.; Bourlès, D. L.; Arnold, M.; Pivot, S.; Baroni, M.; Scharf, A.; Rugel, G.; Bard, E.

2018-04-01

After 6 years of 36Cl routine operation, more than 6000 unknown samples have been measured at the 5MV French accelerator mass spectrometry (AMS) national facility ASTER (CEREGE, Aix en Provence). This paper presents the long term behavior of ASTER through the analysis of the measurements of the most used chlorine standards and reference materials, KNSTD1600, SM-Cl-12 and SM-CL-13 over a 46 months' time period. Comparison of measured chlorine concentrations (both 35Cl and 36Cl) from ice samples on two AMS facilities operating at 5MV (ASTER) and 6MV (DREAMS, Helmholtz-Zentrum Dresden-Rossendorf) and normalizing to two different reference materials agree within uncertainties making both reference materials (SM-Cl-12 and KNSTD1600) suitable for 36Cl measurement at ASTER.

VESPA. Behaviour of long-lived fission and activation products in the nearfield of a nuclear waste repository and the possibilities of their retention

Energy Technology Data Exchange (ETDEWEB)

Bischofer, Barbara; Hagemann, Sven [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany); Altmaier, Marcus [Karlsruher Institut fuer Technologie (KIT) (Germany); and others

2016-06-15

The present document is the final report of the Joint Research Project VESPA (Behaviour of Long-lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of Their Retention), started in July 2010 with a duration of four years. The following four institutions were collaborative Partners in VESPA: - Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH - Institut fuer Energie- und Klimaforschung, IEK-6: Nukleare Entsorgung und Reaktorsicherheit, Forschungszentrum Juelich (FZJ) - Institut fuer Ressourcenoekologie (IRE), Helmholtz-Zentrum Dresden-Rossendorf (HZDR) - Institut fuer Nukleare Entsorgung (INE), Karlsruher Institut fuer Technologie (KIT) VESPA was funded by the German Federal Ministry of Economics and Energy (BMWi) under the contract numbers 02 E 10770 (GRS), 02 E 10780 (FZJ-IEF-6), 02 E 10790 (HZDR-IRE), 02 E 10800 (KIT-INE).

The upgraded cold neutron triple-axis spectrometer FLEXX – enhanced capabilities by new instrumental options

Directory of Open Access Journals (Sweden)

Habicht Klaus

2015-01-01

Full Text Available The upgrade of the cold neutron triple axis spectrometer FLEXX, a work-horse instrument for inelastic neutron scattering matching the sample environment capabilities at Helmholtz-Zentrum Berlin, has been successfully accomplished. Experiments confirmed an order of magnitude gain in flux now allowing for intensity demanding options to be fully exploited at FLEXX. In this article, we describe the layout and design of two newly available FLEXX instrument options in detail. The new Heusler analyzer gives an increase of the detected polarized neutron flux due to its superior focusing properties, significantly improving the feasibility of future polarized and neutron resonance spin echo experiments. The MultiFLEXX option provides simultaneous access to large regions in wavevector and energy space for inelastic excitations thus adding mapping capabilities to the spectrometer.

Hybrid friction diffusion bonding of 316L stainless steel tube-to-tube sheet joints for coil-wound heat exchangers

Energy Technology Data Exchange (ETDEWEB)

Haneklaus, Nils; Cionea, Cristian; Reuven, Rony; Frazer, David; Hosemann, Peter; Peterson, Per F. [Dept of Nuclear Engineering, University of California, Berkeley (United States)

2016-11-15

Hybrid friction diffusion bonding (HFDB) is a solid-state bonding process first introduced by Helmholtz-Zentrum Geesthacht to join aluminum tube-to-tube sheet joints of Coil-wound heat exchangers (CWHE). This study describes how HFDB was successfully used to manufacture 316L test samples simulating tube-to-tube sheet joints of stainless steel CWHE for molten salt coolants as foreseen in several advanced nuclear- and thermal solar power plants. Engineering parameters of the test sample fabrication are presented and results from subsequent non-destructive vacuum decay leak testing and destructive tensile pull-out testing are discussed. The bonded areas of successfully fabricated samples as characterized by tube rupture during pull-out tensile testing, were further investigated using optical microscopy and scanning electron microscopy including electron backscatter diffraction.

Decay of MHD-scale Kelvin-Helmholtz vortices mediated by parasitic electron dynamics

International Nuclear Information System (INIS)

Nakamura, T.K.M.; Hayashi, D.; Fujimoto, M.; Shinohara, I.

2004-01-01

We have simulated nonlinear development of MHD-scale Kelvin-Helmholtz (KH) vortices by a two-dimensional two-fluid system including finite electron inertial effects. In the presence of moderate density jump across a shear layer, in striking contrast to MHD results, MHD KH vortices are found to decay by the time one eddy turnover is completed. The decay is mediated by smaller vortices that appear within the parent vortex and stays effective even when the shear layer width is made larger. It is shown that the smaller vortices are basically of MHD nature while the seeding for these is achieved by the electron inertial effect. Application of the results to the magnetotail boundary layer is discussed

Diffusion at the Earth magnetopause: enhancement by Kelvin-Helmholtz instability

Directory of Open Access Journals (Sweden)

R. Smets

2007-02-01

Full Text Available Using hybrid simulations, we examine how particles can diffuse across the Earth's magnetopause because of finite Larmor radius effects. We focus on tangential discontinuities and consider a reversal of the magnetic field that closely models the magnetopause under southward interplanetary magnetic field. When the Larmor radius is on the order of the field reversal thickness, we show that particles can cross the discontinuity. We also show that with a realistic initial shear flow, a Kelvin-Helmholtz instability develops that increases the efficiency of the crossing process. We investigate the distribution functions of the transmitted ions and demonstrate that they are structured according to a D-shape. It accordingly appears that magnetic reconnection at the magnetopause is not the only process that leads to such specific distribution functions. A simple analytical model that describes the built-up of these functions is proposed.

Magnetohydrodynamic Kelvin-Helmholtz instabilities in astrophysics. 4. Single shear layer in MHD flows

Energy Technology Data Exchange (ETDEWEB)

Ferrari, A [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale); Trussoni, E [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.). Inst. fuer Extraterrestrische Physik)

1983-11-01

In this further paper on the physics of Kelvin-Helmholtz instabilities the case in which the fluids in relative motion are magnetized and separated by a shear layer is investigated. The present study points out, with respect to previous treatments, that different velocity profiles affect perturbations of short wavelength (as compared to the scale of the shear). Another new result is in the destabilizing effect, even in the subsonic regime, of the magnetic field on modes neutrally stable in the vortex sheet approximation. Such a behaviour is analogous to that found in the fluid case for Mach numbers >approx. = to 2. Possible astrophysical implications are also discussed.

Optimal 25-Point Finite-Difference Subgridding Techniques for the 2D Helmholtz Equation

Directory of Open Access Journals (Sweden)

Tingting Wu

2016-01-01

Full Text Available We present an optimal 25-point finite-difference subgridding scheme for solving the 2D Helmholtz equation with perfectly matched layer (PML. This scheme is second order in accuracy and pointwise consistent with the equation. Subgrids are used to discretize the computational domain, including the interior domain and the PML. For the transitional node in the interior domain, the finite difference equation is formulated with ghost nodes, and its weight parameters are chosen by a refined choice strategy based on minimizing the numerical dispersion. Numerical experiments are given to illustrate that the newly proposed schemes can produce highly accurate seismic modeling results with enhanced efficiency.

Imaging of the internal structure of comet 67P/Churyumov-Gerasimenko from radiotomography CONSERT Data (Rosetta Mission) through a full 3D regularized inversion of the Helmholtz equations on functional spaces

Science.gov (United States)

Barriot, Jean-Pierre; Serafini, Jonathan; Sichoix, Lydie; Benna, Mehdi; Kofman, Wlodek; Herique, Alain

We investigate the inverse problem of imaging the internal structure of comet 67P/ Churyumov-Gerasimenko from radiotomography CONSERT data by using a coupled regularized inversion of the Helmholtz equations. A first set of Helmholtz equations, written w.r.t a basis of 3D Hankel functions describes the wave propagation outside the comet at large distances, a second set of Helmholtz equations, written w.r.t. a basis of 3D Zernike functions describes the wave propagation throughout the comet with avariable permittivity. Both sets are connected by continuity equations over a sphere that surrounds the comet. This approach, derived from GPS water vapor tomography of the atmosphere,will permit a full 3D inversion of the internal structure of the comet, contrary to traditional approaches that use a discretization of space at a fraction of the radiowave wavelength.

Magnetohydrodynamic Kelvin-Helmholtz instabilities in astrophysics. 1. Relativistic flows-plane boundary layer in vortex sheet approximation

Energy Technology Data Exchange (ETDEWEB)

Ferrari, A; Trussoni, E; Zaninetti, L [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica)

1980-11-01

In this paper some unsolved problems of the linear MHD Kelvin-Helmholtz instability are re-examined, starting from the analysis of relativistic (and non-relativistic) flows in the approximation of a plane vortex sheet, for the contact layer between the fluids in relative motion. Results are discussed for a range of physical parameters in specific connection with application to models of jets in extragalactic radio sources. Other physical aspects of the instability will be considered in forthcoming papers.

On Multiple Hall-Like Electron Currents and Tripolar Guide Magnetic Field Perturbations During Kelvin-Helmholtz Waves

Science.gov (United States)

Sturner, Andrew P.; Eriksson, Stefan; Nakamura, Takuma; Gershman, Daniel J.; Plaschke, Ferdinand; Ergun, Robert E.; Wilder, Frederick D.; Giles, Barbara; Pollock, Craig; Paterson, William R.; Strangeway, Robert J.; Baumjohann, Wolfgang; Burch, James L.

2018-02-01

Two magnetopause current sheet crossings with tripolar guide magnetic field signatures were observed by multiple Magnetosphere Multiscale (MMS) spacecraft during Kelvin-Helmholtz wave activity. The two out-of-plane magnetic field depressions of the tripolar guide magnetic field are largely supported by the observed in-plane electron currents, which are reminiscent of two clockwise Hall current loop systems. A comparison with a three-dimensional kinetic simulation of Kelvin-Helmholtz waves and vortex-induced reconnection suggests that MMS likely encountered the two Hall magnetic field depressions on either side of a magnetic reconnection X-line. Moreover, MMS observed an out-of-plane current reversal and a corresponding in-plane magnetic field rotation at the center of one of the current sheets, suggesting the presence of two adjacent flux ropes. The region inside one of the ion-scale flux ropes was characterized by an observed decrease of the total magnetic field, a strong axial current, and significant enhancements of electron density and parallel electron temperature. The flux rope boundary was characterized by currents opposite this axial current, strong in-plane and converging electric fields, parallel electric fields, and weak electron-frame Joule dissipation. These return current region observations may reflect a need to support the axial current rather than representing local reconnection signatures in the absence of any exhausts.

Inverse random source scattering for the Helmholtz equation in inhomogeneous media

Science.gov (United States)

Li, Ming; Chen, Chuchu; Li, Peijun

2018-01-01

This paper is concerned with an inverse random source scattering problem in an inhomogeneous background medium. The wave propagation is modeled by the stochastic Helmholtz equation with the source driven by additive white noise. The goal is to reconstruct the statistical properties of the random source such as the mean and variance from the boundary measurement of the radiated random wave field at multiple frequencies. Both the direct and inverse problems are considered. We show that the direct problem has a unique mild solution by a constructive proof. For the inverse problem, we derive Fredholm integral equations, which connect the boundary measurement of the radiated wave field with the unknown source function. A regularized block Kaczmarz method is developed to solve the ill-posed integral equations. Numerical experiments are included to demonstrate the effectiveness of the proposed method.

Numerical solution of the helmholtz equation for the superellipsoid via the galerkin method

Directory of Open Access Journals (Sweden)

Hy Dinh

2013-01-01

Full Text Available The objective of this work was to find the numerical solution of the Dirichlet problem for the Helmholtz equation for a smooth superellipsoid. The superellipsoid is a shape that is controlled by two parameters. There are some numerical issues in this type of an analysis; any integration method is affected by the wave number k, because of the oscillatory behavior of the fundamental solution. In this case we could only obtain good numerical results for super ellipsoids that were more shaped like super cones, which is a narrow range of super ellipsoids. The formula for these shapes was: $x=cos(xsin(y^{n},y=sin(xsin(y^{n},z=cos(y$ where $n$ varied from 0.5 to 4. The Helmholtz equation, which is the modified wave equation, is used in many scattering problems. This project was funded by NASA RI Space Grant for testing of the Dirichlet boundary condition for the shape of the superellipsoid. One practical value of all these computations can be getting a shape for the engine nacelles in a ray tracing the space shuttle. We are researching the feasibility of obtaining good convergence results for the superellipsoid surface. It was our view that smaller and lighter wave numbers would reduce computational costs associated with obtaining Galerkin coefficients. In addition, we hoped to significantly reduce the number of terms in the infinite series needed to modify the original integral equation, all of which were achieved in the analysis of the superellipsoid in a finite range. We used the Green's theorem to solve the integral equation for the boundary of the surface. Previously, multiple surfaces were used to test this method, such as the sphere, ellipsoid, and perturbation of the sphere, pseudosphere and the oval of Cassini Lin and Warnapala , Warnapala and Morgan .

Long-term stable transmission of 3-keV Ne7+ ions guided through nanocapillaries in polymers

International Nuclear Information System (INIS)

Stolterfoht, N.; Herczku, P.; Juhász, Z.; Kovács, S.T.S.; Rácz, R.; Biri, S.; Sulik, B.

2016-01-01

We studied blocking effects on 3-keV Ne 7+ ion guiding through nanocapillaries in highly insulating polyethylene terephthalate (PET) manufactured at different laboratories. The experiments were motivated in view of previous measurement with PET capillaries prepared at the GSI Helmholtz-Zentrum for which significant blocking effects were observed, whereas in various previous studies with PET capillaries these effects could not be detected. As the blocking effect on the GSI capillaries strongly depends on their areal density, similar dependencies were studied with the FLNR capillaries. Long-term stable transmission was observed for all densities of the FLNR capillaries in contrast to the previous results. These observations are interpreted by differences in the capillary surface conductivities in accordance with charge patch formations within the capillaries. It is pointed out that the observed stable transmission is favorable for applications of ion guiding in capillaries.

Long-term stable transmission of 3-keV Ne{sup 7+} ions guided through nanocapillaries in polymers

Energy Technology Data Exchange (ETDEWEB)

Stolterfoht, N., E-mail: nico@stolterfoht.com [Helmholtz-Zentrum Berlin fnr Materialien und Energie, 14109 Berlin (Germany); Herczku, P.; Juhász, Z.; Kovács, S.T.S.; Rácz, R.; Biri, S.; Sulik, B. [Institute of Nuclear Research (ATOMKI), 4001 Debrecen (Hungary)

2016-11-15

We studied blocking effects on 3-keV Ne{sup 7+} ion guiding through nanocapillaries in highly insulating polyethylene terephthalate (PET) manufactured at different laboratories. The experiments were motivated in view of previous measurement with PET capillaries prepared at the GSI Helmholtz-Zentrum for which significant blocking effects were observed, whereas in various previous studies with PET capillaries these effects could not be detected. As the blocking effect on the GSI capillaries strongly depends on their areal density, similar dependencies were studied with the FLNR capillaries. Long-term stable transmission was observed for all densities of the FLNR capillaries in contrast to the previous results. These observations are interpreted by differences in the capillary surface conductivities in accordance with charge patch formations within the capillaries. It is pointed out that the observed stable transmission is favorable for applications of ion guiding in capillaries.

Seafloor identification in sonar imagery via simulations of Helmholtz equations and discrete optimization

Science.gov (United States)

Engquist, Björn; Frederick, Christina; Huynh, Quyen; Zhou, Haomin

2017-06-01

We present a multiscale approach for identifying features in ocean beds by solving inverse problems in high frequency seafloor acoustics. The setting is based on Sound Navigation And Ranging (SONAR) imaging used in scientific, commercial, and military applications. The forward model incorporates multiscale simulations, by coupling Helmholtz equations and geometrical optics for a wide range of spatial scales in the seafloor geometry. This allows for detailed recovery of seafloor parameters including material type. Simulated backscattered data is generated using numerical microlocal analysis techniques. In order to lower the computational cost of the large-scale simulations in the inversion process, we take advantage of a pre-computed library of representative acoustic responses from various seafloor parameterizations.

Acoustic energy harvesting using an electromechanical Helmholtz resonator.

Science.gov (United States)

Liu, Fei; Phipps, Alex; Horowitz, Stephen; Ngo, Khai; Cattafesta, Louis; Nishida, Toshikazu; Sheplak, Mark

2008-04-01

This paper presents the development of an acoustic energy harvester using an electromechanical Helmholtz resonator (EMHR). The EMHR consists of an orifice, cavity, and a piezoelectric diaphragm. Acoustic energy is converted to mechanical energy when sound incident on the orifice generates an oscillatory pressure in the cavity, which in turns causes the vibration of the diaphragm. The conversion of acoustic energy to electrical energy is achieved via piezoelectric transduction in the diaphragm of the EMHR. Moreover, the diaphragm is coupled with energy reclamation circuitry to increase the efficiency of the energy conversion. Lumped element modeling of the EMHR is used to provide physical insight into the coupled energy domain dynamics governing the energy reclamation process. The feasibility of acoustic energy reclamation using an EMHR is demonstrated in a plane wave tube for two power converter topologies. The first is comprised of only a rectifier, and the second uses a rectifier connected to a flyback converter to improve load matching. Experimental results indicate that approximately 30 mW of output power is harvested for an incident sound pressure level of 160 dB with a flyback converter. Such power level is sufficient to power a variety of low power electronic devices.

MHD Kelvin-Helmholtz instability in non-hydrostatic equilibrium

International Nuclear Information System (INIS)

Laghouati, Y; Bouabdallah, A; Zizi, M; Alemany, A

2007-01-01

The present work deals with the linear stability of a magnetohydrodynamic shear flow so that a stratified inviscid fluid rotating about a vertical axis when a uniform magnetic field is applied in the direction of the streaming or zonal flow. In geophysical flow, the stability of the flow is determined by taking into account the nonhydrostatic condition depending on Richardson number R i and the deviation δ from hydrostatic equilibrium. According to Stone (Stone P H 1971 J. Fluid. Mech. 45 659), it is shown that such deviation δ decreases the growth rates of three kinds of instability which can appear as geostrophic (G), symmetric (S) and Kelvin-Helmholtz (K-H) instabilities. To be specific, the evolution of the flow is therefore considered in the light of the influence of magnetic field, particularly, on K-H instability. The results of this study are presented by the linear stability of a magnetohydrodynamic, with horizontal free-shear flow of stratified fluid, subject to rotation about the vertical axis and uniform magnetic field in the zonal direction. Results are discussed and compared to previous works as Chandrasekhar (Chandrasekhar S 1961 Hydrodynamic and hydromagnetic stability (Oxford: Clarendon Press) chapter 11 pp 481-513) and Stone

Interactions between two magnetohydrodynamic Kelvin-Helmholtz instabilities

International Nuclear Information System (INIS)

Lai, S. H.; Ip, W.-H.

2011-01-01

Kelvin-Helmholtz instability (KHI) driven by velocity shear is a generator of waves found away from the vicinity of the velocity-shear layers since the fast-mode waves radiated from the surface perturbation can propagate away from the transition layer. Thus the nonlinear evolution associated with KHI is not confined near the velocity-shear layer. To understand the physical processes in multiple velocity-shear layers, the interactions between two KHIs at a pair of tangential discontinuities are studied by two-dimensional magnetohydrodynamic simulations. It is shown that the interactions between two neighboring velocity-shear layers are dominated by the propagation of the fast-mode waves radiated from KHIs in a nonuniform medium. That is, the fast-mode Mach number of the surface waves M Fy , a key factor of the nonlinear evolution of KHI, will vary with the nonuniform background plasma velocity due to the existence of two neighboring velocity-shear layers. As long as the M Fy observed in the plasma rest frame across the neighboring velocity-shear layer is larger than one, newly formed fast-mode Mach-cone-like (MCL) plane waves generated by the fast-mode waves can be found in this region. As results of the interactions of two KHIs, reflection and distortion of the MCL plane waves generate the turbulence and increase the plasma temperature, which provide possible mechanisms of heating and accelerating local plasma between two neighboring velocity-shear layers.

Increase in effectiveness of low frequency acoustic liners by use of coupled Helmholtz resonators

Science.gov (United States)

Dean, L. W.

1977-01-01

Coupling of Helmholtz resonators in a low-frequency absorber array was studied as a means for increasing the effectiveness for absorbing low-frequency core engine noise. The equations for the impedance of the coupled-resonator systems were developed in terms of uncoupled-resonator parameters, and the predicted impedance for a parallel-coupled scheme is shown to compare favorably with measurements from a test model. In addition, attenuation measurements made in a flow duct on test coupled-resonator panels are shown to compare favorably with predicted values. Finally, the parallel-coupled concept is shown to give significantly more attenuation than that of a typical uncoupled resonator array of the same total volume.

Nuclear safety research in HGF 2012

International Nuclear Information System (INIS)

Anon.

2013-01-01

Nuclear Competence Association. The Forschungszentrum Juelich GmbH, HZDR Helmholtz-Zentrum Dresden-Rossendorf and the KIT Karlsruhe Institute of Technology are involved in the Nuclear Safety Research Program within the Helmholtz Association. The work and results in 2012 are presented. (orig.)

Annual report 2011. Institute of Ion Beam Physics and Materials Research

International Nuclear Information System (INIS)

Cordeiro, A.L.; Fassbender, J.; Heera, V.; Helm, M.

2012-01-01

The first year of membership of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in the Helmholtz Association of German Research Centers (HGF) was a year of many changes also for the Institute of Ion Beam Physics and Materials Research (IIM). The transition period, however, is not yet over, since the full integration of the Center into the HGF will only be completed in the next period of the so-called program-oriented funding (POF). This funding scheme addresses the six core research fields identified by the Helmholtz Association (Energy; Earth and Environment; Health; Key Technologies; Structure of Matter; Aeronautics, Space and Transport) to deal with the grand challenges faced by society, science and industry. Since the Institute has strong contributions to both core fields ''Key Technologies'' and ''Structure of Matter'', intense discussions were held amongst the leading scientists of the Institute, across the Institutes of the HZDR, and finally with leading scientists of other Helmholtz centers, to determine the most appropriate classification of the Institute's research. At the end we decided to establish ourselves in Structure of Matter, the core field in which most of the large-scale photon, neutron and ion facilities in Germany are located. As a consequence, the Ion Beam Center (IBC) of the Institute submitted an application to become a HGF recognized large-scale facility, providing more than 50% of its available beam time to external users. This application perfectly reflects the development of the IBC over more than a decade as a European Union funded infrastructure in the framework of the projects ''Center for Application of Ion Beams in Materials Research (AIM)'' (1998-2000, 2000-2003, 2006-2010) and subsequently as the coordinator of the integrated infrastructure initiative (I3) ''Support of Public and Industrial Research using Ion Beam Technology (SPIRIT)'' (2009-2013). Another part of the Institute's activities is dedicated to exploit the infrared

Mean shear flows, zonal flows, and generalized Kelvin-Helmholtz modes in drift wave turbulence: A minimal model for L→H transition

International Nuclear Information System (INIS)

Kim, Eun-jin; Diamond, P.H.

2003-01-01

The dynamics of and an interplay among structures (mean shear flows, zonal flows, and generalized Kelvin-Helmholtz modes) are studied in drift wave turbulence. Mean shear flows are found to inhibit the nonlinear generation of zonal flows by weakening the coherent modulation response of the drift wave spectrum. Based on this result, a minimal model for the L→H (low- to high-confinement) transition is proposed, which involves the amplitude of drift waves, zonal flows, and the density gradient. A transition to quiescent H-mode sets in as the profile becomes sufficiently steep to completely damp out drift waves, following an oscillatory transition phase where zonal flows regulate drift wave turbulence. The different roles of mean flows and zonal flows are elucidated. Finally, the effect of poloidally nonaxisymmetric structures (generalized Kelvin-Helmholtz mode) on anomalous transport is investigated, especially in reference to damping of collisionless zonal flows. Results indicate that nonlinear excitation of this structure can be potentially important in enhancing anomalous transport as well as in damping zonal flows

Electron Debye scale Kelvin-Helmholtz instability: Electrostatic particle-in-cell simulations

International Nuclear Information System (INIS)

Lee, Sang-Yun; Lee, Ensang; Kim, Khan-Hyuk; Lee, Dong-Hun; Seon, Jongho; Jin, Ho

2015-01-01

In this paper, we investigated the electron Debye scale Kelvin-Helmholtz (KH) instability using two-dimensional electrostatic particle-in-cell simulations. We introduced a velocity shear layer with a thickness comparable to the electron Debye length and examined the generation of the KH instability. The KH instability occurs in a similar manner as observed in the KH instabilities in fluid or ion scales producing surface waves and rolled-up vortices. The strength and growth rate of the electron Debye scale KH instability is affected by the structure of the velocity shear layer. The strength depends on the magnitude of the velocity and the growth rate on the velocity gradient of the shear layer. However, the development of the electron Debye scale KH instability is mainly determined by the electric field generated by charge separation. Significant mixing of electrons occurs across the shear layer, and a fraction of electrons can penetrate deeply into the opposite side fairly far from the vortices across the shear layer

80 K - Helium circuit with innovative, gas-bearing, oil-free turbo compressor. Conception, realization, commissioning and test of the 80 K refrigeration supply for the superconducting electron source at HZB; 80 K - Helium-Kreis mit innovativem, gasgelagertem, oelfreiem Turbokompressor. Konzeption, Realisierung, Inbetriebnahme und Test der 80 K-Kaelteversorgung fuer die supraleitenden Elektronenquelle am HZB

Energy Technology Data Exchange (ETDEWEB)

Gloeckner, Felix [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany)

2017-07-01

The system presented in this paper supplies the test module for the superconducting electron source (GunLab) at the Helmholtz-Zentrum Berlin (HZB) with 500 W cooling capacity at 80 K.Since direct evaporation of liquid nitrogen in the module is not desirable for safety reasons, the system operates with an intermediate helium circuit. In order to use not only the latent cold of liquid nitrogen, but also the sensitive component, a new concept consisting of a dual heat exchanger and a bath cryostat is used. The coldbox also contains an adjustable bypass with integrated electric heater for test purposes.A new type of warm compressor is used to circulate the helium. The turbo compressor is oil-free, gas-stored and in helium-tight semi-hermetic design. In order to take advantage of these unique properties, Fischer Engineering AG has adapted the turbo compressor for use with helium.The paper concludes with a test of the system and an insight into the current operating experience, as well as a preview of the next, larger version of bERLinPro. [German] Die in diesem Paper vorgestellte Anlage versorgt das Testmodul fuer die supraleitende Elektronenquelle (GunLab) am Helmholtz-Zentrum Berlin (HZB) mit 500 W Kuehlleistung bei 80 K. Da eine Direktverdampfung von Fluessigstickstoff im Modul aus Sicherheitsgruenden nicht erwuenscht ist, arbeitet die Anlage mit einem Heliumzwischenkreis. Um nicht nur die latente Kaelte des fluessigen Stickstoffs, sondern auch den sensiblen Anteil zu nutzen, wird ein neues Konzept, bestehend aus einem Dualwaermeuebertrager und einem Badkryostaten verwendet. Die Coldbox enthaelt fuer Testzwecke darueber hinaus einen regelbaren Bypass mit inte-griertem elektrischem Heizer. Fuer die Umwaelzung des Heliums kommt eine neue Art eines warmen Kompressors zum Einsatz. Der Turbokom-pressor ist oelfrei, gasgelagert und in heliumdichter halb-hermetischer Bauweise ausgefuehrt. Um dessen, in dieser Leistungsklasse einzigartigen Eigenschaften zu nutzen, wurde der

Magnetohydrodynamic Kelvin-Helmholtz instabilities in astrophysics. 2. Cylindrical boundary layer in vortex sheet approximation

Energy Technology Data Exchange (ETDEWEB)

Ferrari, A [Max-Planck-Institut fuer Extraterrestrische Physik, Garching b. Muenchen (Germany, F.R.); Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica); Trussoni, E; Zaninetti, L [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica

1981-09-01

This second paper of the series is devoted to Kelvin-Helmholtz instabilities in cylindrical boundary layer flows (jets). The vortex-sheet approximation is still used, and compressible flows are studied in subsonic, transonic, supersonic and relativistic regimes. Magnetic field effects are analysed, together with density contrast inside and outside the jet. The general result is that, due to the onset of a so-called reflection branch of resonant modes, jets are always unstable, both to pinching and helical perturbations with wavelengths of the order of the jet circumference. In particular the time-scales for instability are such that this certainly plays a significant part in the morphology and energetics of extended radio sources.

Blob Formation and Ejection in Coronal Jets due to the Plasmoid and Kelvin–Helmholtz Instabilities

Energy Technology Data Exchange (ETDEWEB)

Ni, Lei; Lin, Jun [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Zhang, Qing-Min [Key Laboratory for Dark Matter and Space Science, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Murphy, Nicholas A., E-mail: leini@ynao.ac.cn [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2017-05-20

We perform 2D resistive magnetohydrodynamic simulations of coronal jets driven by flux emergence along the lower boundary. The reconnection layers are susceptible to the formation of blobs that are ejected in the jet. Our simulation with low plasma β (Case I) shows that magnetic islands form easily and propagate upward in the jet. These islands are multithermal and thus are predicted to show up in hot channels (335 Å and 211 Å) and the cool channel (304 Å) in observations by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory . The islands have maximum temperatures of 8 MK, lifetimes of 120 s, diameters of 6 Mm, and velocities of 200 km s{sup −1}. These parameters are similar to the properties of blobs observed in extreme-ultraviolet (EUV) jets by AIA. The Kelvin–Helmholtz instability develops in our simulation with moderately high plasma β (Case II) and leads to the formation of bright vortex-like blobs above the multiple high magnetosonic Mach number regions that appear along the jet. These vortex-like blobs can also be identified in the AIA channels. However, they eventually move downward and disappear after the high magnetosonic Mach number regions disappear. In the lower plasma β case, the lifetime for the jet is shorter, the jet and magnetic islands are formed with higher velocities and temperatures, the current-sheet fragments are more chaotic, and more magnetic islands are generated. Our results show that the plasmoid instability and Kelvin–Helmholtz instability along the jet are both possible causes of the formation of blobs observed at EUV wavelengths.

Simulation of an MSLB scenario using the 3D neutron kinetic core model DYN3D coupled with the CFD software Trio-U

Energy Technology Data Exchange (ETDEWEB)

Grahn, Alexander, E-mail: a.grahn@hzdr.de; Gommlich, André; Kliem, Sören; Bilodid, Yurii; Kozmenkov, Yaroslav

2017-04-15

Highlights: • Improved thermal-hydraulic description of nuclear reactor cores. • Providing reactor dynamics code with realistic thermal-hydraulic boundary conditions. • Possibility of three-dimensional flow phenomena in the core, such as cross flow, flow reversal. • Simulation at higher spatial resolution as compared to system codes. - Abstract: In the framework of the European project NURESAFE, the reactor dynamics code DYN3D, developed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), was coupled with the Computational Fluid Dynamics (CFD) solver Trio-U, developed at CEA France, in order to replace DYN3D’s one-dimensional hydraulic part with a full three-dimensional description of the coolant flow in the reactor core at higher spatial resolution. The present document gives an introduction into the coupling method and shows results of its application to the simulation of a Main Steamline Break (MSLB) accident of a Pressurised Water Reactor (PWR).

Transmutation of high-level radioactive waste - Perspectives

CERN Document Server

Junghans, Arnd; Grosse, Eckart; Hannaske, Roland; Kögler, Toni; Massarczyk, Ralf; Schwengner, Ronald; Wagner, Andreas

2014-01-01

In a fast neutron spectrum essentially all long-lived actinides (e.g. Plutonium) undergo fission and thus can be transmuted into generally short lived fission products. Innovative nuclear reactor concepts e.g. accelerator driven systems (ADS) are currently in development that foresee a closed fuel cycle. The majority of the fissile nuclides (uranium, plutonium) shall be used for power generation and only fission products will be put into final disposal that needs to last for a historical time scale of only 1000 years. For the transmutation of high-level radioactive waste a lot of research and development is still required. One aspect is the precise knowledge of nuclear data for reactions with fast neutrons. Nuclear reactions relevant for transmutation are being investigated in the framework of the european project ERINDA. First results from the new neutron time-of-flight facility nELBE at Helmholtz-Zentrum Dresden-Rossendorf will be presented.

Reconstruction of propagating Kelvin-Helmholtz vortices at Mercury's magnetopause

Science.gov (United States)

Sundberg, Torbjörn; Boardsen, Scott A.; Slavin, James A.; Blomberg, Lars G.; Cumnock, Judy A.; Solomon, Sean C.; Anderson, Brian J.; Korth, Haje

2011-12-01

A series of quasi-periodic magnetopause crossings were recorded by the MESSENGER spacecraft during its third flyby of Mercury on 29 September 2009, likely caused by a train of propagating Kelvin-Helmholtz (KH) vortices. We here revisit the observations to study the internal structure of the waves. Exploiting MESSENGER's rapid traversal of the magnetopause, we show that the observations permit a reconstruction of the structure of a rolled-up KH vortex directly from the spacecraft's magnetic field measurements. The derived geometry is consistent with all large-scale fluctuations in the magnetic field data, establishes the non-linear nature of the waves, and shows their vortex-like structure. In several of the wave passages, a reduction in magnetic field strength is observed in the middle of the wave, which is characteristic of rolled-up vortices and is related to the increase in magnetic pressure required to balance the centrifugal force on the plasma in the outer regions of a vortex, previously reported in computer simulations. As the KH wave starts to roll up, the reconstructed geometry suggests that the vortices develop two gradual transition regions in the magnetic field, possibly related to the mixing of magnetosheath and magnetospheric plasma, situated at the leading edges from the perspectives of both the magnetosphere and the magnetosheath.

An efficient Helmholtz solver for acoustic transversely isotropic media

KAUST Repository

Wu, Zedong

2017-11-11

The acoustic approximation, even for anisotropic media, is widely used in current industry imaging and inversion algorithms mainly because P-waves constitute the majority of the energy recorded in seismic exploration. The resulting acoustic formulas tend to be simpler, resulting in more efficient implementations, and depend on less medium parameters. However, conventional solutions of the acoustic wave equation with higher-order derivatives suffer from S-wave artifacts. Thus, we propose to separate the quasi-P wave propagation in anisotropic media into the elliptic anisotropic operator (free of the artifacts) and the non-elliptic-anisotropic components, which form a pseudo-differential operator. We, then, develop a separable approximation of the dispersion relation of non-elliptic-anisotropic components, specifically for transversely isotropic (TI) media. Finally, we iteratively solve the simpler lower-order elliptical wave equation for a modified source function that includes the non-elliptical terms represented in the Fourier domain. A frequency domain Helmholtz formulation of the approach renders the iterative implementation efficient as the cost is dominated by the Lower-Upper (LU) decomposition of the impedance matrix for the simpler elliptical anisotropic model. Also, the resulting wavefield is free of S-wave artifacts and has balanced amplitude. Numerical examples show that the method is reasonably accurate and efficient.

Kelvin-Helmholtz evolution in subsonic cold streams feeding galaxies

Science.gov (United States)

Angulo, Adrianna; Coffing, S.; Kuranz, C.; Drake, R. P.; Klein, S.; Trantham, M.; Malamud, G.

2017-10-01

The most prolific star formers in cosmological history lie in a regime where dense filament structures carried substantial mass into the galaxy to sustain star formation without producing a shock. However, hydrodynamic instabilities present on the filament surface limit the ability of such structures to deliver dense matter deeply enough to sustain star formation. Simulations lack the finite resolution necessary to allow fair treatment of the instabilities present at the stream boundary. Using the Omega EP laser, we simulate this mode of galaxy formation with a cold, dense, filament structure within a hotter, subsonic flow and observe the interface evolution. Machined surface perturbations stimulate the development of the Kelvin-Helmholtz (KH) instability due to the resultant shear between the two media. A spherical crystal imaging system produces high-resolution radiographs of the KH structures along the filament surface. The results from the first experiments of this kind, using a rod with single-mode, long-wavelength modulations, will be discussed. This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0002956, and the National Laser User Facility Program, Grant Number DE-NA0002719, and through.

An efficient Helmholtz solver for acoustic transversely isotropic media

KAUST Repository

Wu, Zedong; Alkhalifah, Tariq Ali

2017-01-01

The acoustic approximation, even for anisotropic media, is widely used in current industry imaging and inversion algorithms mainly because P-waves constitute the majority of the energy recorded in seismic exploration. The resulting acoustic formulas tend to be simpler, resulting in more efficient implementations, and depend on less medium parameters. However, conventional solutions of the acoustic wave equation with higher-order derivatives suffer from S-wave artifacts. Thus, we propose to separate the quasi-P wave propagation in anisotropic media into the elliptic anisotropic operator (free of the artifacts) and the non-elliptic-anisotropic components, which form a pseudo-differential operator. We, then, develop a separable approximation of the dispersion relation of non-elliptic-anisotropic components, specifically for transversely isotropic (TI) media. Finally, we iteratively solve the simpler lower-order elliptical wave equation for a modified source function that includes the non-elliptical terms represented in the Fourier domain. A frequency domain Helmholtz formulation of the approach renders the iterative implementation efficient as the cost is dominated by the Lower-Upper (LU) decomposition of the impedance matrix for the simpler elliptical anisotropic model. Also, the resulting wavefield is free of S-wave artifacts and has balanced amplitude. Numerical examples show that the method is reasonably accurate and efficient.

First-order system least-squares for the Helmholtz equation

Energy Technology Data Exchange (ETDEWEB)

Lee, B.; Manteuffel, T.; McCormick, S.; Ruge, J.

1996-12-31

We apply the FOSLS methodology to the exterior Helmholtz equation {Delta}p + k{sup 2}p = 0. Several least-squares functionals, some of which include both H{sup -1}({Omega}) and L{sup 2}({Omega}) terms, are examined. We show that in a special subspace of [H(div; {Omega}) {intersection} H(curl; {Omega})] x H{sup 1}({Omega}), each of these functionals are equivalent independent of k to a scaled H{sup 1}({Omega}) norm of p and u = {del}p. This special subspace does not include the oscillatory near-nullspace components ce{sup ik}({sup {alpha}x+{beta}y)}, where c is a complex vector and where {alpha}{sub 2} + {beta}{sup 2} = 1. These components are eliminated by applying a non-standard coarsening scheme. We achieve this scheme by introducing {open_quotes}ray{close_quotes} basis functions which depend on the parameter pair ({alpha}, {beta}), and which approximate ce{sup ik}({sup {alpha}x+{beta}y)} well on the coarser levels where bilinears cannot. We use several pairs of these parameters on each of these coarser levels so that several coarse grid problems are spun off from the finer levels. Some extensions of this theory to the transverse electric wave solution for Maxwell`s equations will also be presented.

Critical review of the >>Stellungnahme zur 'deutschen Risikostudie' der Gesellschaft fuer Reaktorsicherheit (GRS)<< by the Bremer Arbeits- und Umweltschutz-Zentrum

International Nuclear Information System (INIS)

Danzmann, H.J.

1981-08-01

In August 1979, the German Risk Study was presented to the public by the Federal Minister of Research and Technology. The main contractor to prepare the German Risk Study is the Gesellschaft fuer Reaktorsicherheit (GRS). The objective of the Study is to investigate the collective risk involved in accidents at nuclear power plants. The essential results and statements of the Study are comprised in a Summary submitted to the public in August 1979, too. In September 1979, the 'Bremer Arbeits- und Umweltschutz-Zentrum' ('BAUZ') published a 'Stellungnahme zur 'deutschen Risikostudie' der Gesellschaft fuer Reaktorsicherheit (GRS)' (Review of the German Risk Study of the Gesellschaft fuer Reaktorsicherheit), dealing only with the summary of this study, however. The BAUZ review is extremely critical of the German Risk Study and ends in condemning the peaceful utilization of nuclear energy as well as the competent authorities. The GRS review critique in hand scrutinizes the BAUZ paper according to the run of the text. Deliberately, one has renounced a comment in such cases where the reproaches slip in the political or ideological field. The object of the BAUZ review as well as of the GRS critique is the matter to be investigated, aim and methods of the investigations and the results of the German Risk Study. The revision of the review acknowledges that in some cases the tendency of criticism is justified. Often, however, the critique is only a sharpened repetition of what the GRS itself has identified as restrictions of accuracy and inherent significance of the results. In most items, however, the critique is rejected as to be wrong or not proof. (orig./HP) [de

Nonlinearity, Viscosity and Air-Compressibility Effects on the Helmholtz Resonant Wave Motion Generated by an Oscillating Twin Body in a Free Surface

Science.gov (United States)

Ananthakrishnan, Palaniswamy

2012-11-01

The problem is of practical relevance in determining the motion response of multi-hull and air-cushion vehicles in high seas and in littoral waters. The linear inviscid problem without surface pressure has been well studied in the past. In the present work, the nonlinear wave-body interaction problem is solved using finite-difference methods based on boundary-fitted coordinates. The inviscid nonlinear problem is tackled using the mixed Eulerian-Lagrangian formulation and the solution of the incompressible Navier-Stokes equations governing the viscous problem using a fractional-step method. The pressure variation in the air cushion is modeled using the isentropic gas equation pVγ = Constant. Results show that viscosity and free-surface nonlinearity significantly affect the hydrodynamic force and the wave motion at the resonant Helmholtz frequency (at which the primary wave motion is the vertical oscillation of the mean surface in between the bodies). Air compressibility suppresses the Helmholtz oscillation and enhances the wave radiation. Work supported by the ONR under the grant N00014-98-1-0151.

Double-reconnected magnetic structures driven by Kelvin-Helmholtz vortices at the Earth's magnetosphere

Science.gov (United States)

Faganello, Matteo; Borgogno, Dario; Califano, Francesco; Pegoraro, Francesco

2015-11-01

In an almost collisionless MagnetoHydrodynamic plasma in a relatively strong magnetic field, stresses can be conveyed far from the region where they are exerted e.g., through the propagation of Alfvèn waves. The forced dynamics of line-tied magnetic structures in solar and stellar coronae is a paradigmatic case. We investigate how this action at a distance develops from the equatorial region of the Kelvin-Helmholtz unstable flanks of the Earth's magnetosphere leading to the onset, at mid latitude in both hemispheres, of correlated double magnetic field line reconnection events that can allow the solar wind plasma to enter the Earth's magnetosphere. This mid-latitude double reconnection process, first investigated in, has been confirmed here by following a large set of individual field lines using a method similar to a Poincarè map.

The wavelength frame multiplication chopper system for the ESS test beamline at the BER II reactor—A concept study of a fundamental ESS instrument principle

International Nuclear Information System (INIS)

Strobl, M.; Bulat, M.; Habicht, K.

2013-01-01

Contributing to the design update phase of the European Spallation Source ESS–scheduled to start operation in 2019–a test beamline is under construction at the BER II research reactor at Helmholtz Zentrum Berlin (HZB). This beamline offers experimental test capabilities of instrument concepts viable for the ESS. The experiments envisaged at this dedicated beamline comprise testing of components as well as of novel experimental approaches and methods taking advantage of the long pulse characteristic of the ESS source. Therefore the test beamline will be equipped with a sophisticated chopper system that provides the specific time structure of the ESS and enables variable wavelength resolutions via wavelength frame multiplication (WFM), a fundamental instrument concept beneficial for a number of instruments at ESS. We describe the unique chopper system developed for these purposes, which allows constant wavelength resolution for a wide wavelength band. Furthermore we discuss the implications for the conceptual design for related instrumentation at the ESS

Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injektor Cavities for the ELBE Linac

CERN Document Server

Arnold, A; Teichert, J; Xiang, R; Eremeev, G V; Kneisel, P; Stirbet, M; Turlington, L

2011-01-01

As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac [1]. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning; the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing [2] was done at HZDR. The following standard surface treatment and the vertical test were carried out at TJNAF’s production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (Ø10 mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects a...

Mobile measurement setup according to IEC 62220-1-2 for DQE determination on digital mammography systems

Science.gov (United States)

Greiter, Matthias B.; Hoeschen, Christoph

2010-04-01

The international standard IEC 62220-1-2 defines the measurement procedure for determination of the detective quantum efficiency (DQE) of digital x-ray imaging devices used in mammography. A mobile setup complying to this standard and adaptable to most current systems was constructed in the Helmholtz Zentrum München to allow for an objective technical comparison of current full field digital mammography units employed in mammography screening in Germany. This article demonstrates the setup's capabilities with a focus on the measurement uncertainties of all quantities contributing to DQE measurements. Evaluation of uncertainties encompasses results from measurements on a Sectra Microdose Mammography in clinical use, as well as on a prototype of a Fujifilm Amulet system at various radiation qualities. Both systems have a high spatial resolution of 50 μm × 50 μm. The modulation transfer function (MTF), noise power spectrum (NPS) and DQE of the Sectra MDM are presented in comparison to results previously published by other authors.

Nuclear Deformation and Neutron Excess as Competing Effects for Dipole Strength in the Pygmy Region

Science.gov (United States)

Massarczyk, R.; Schwengner, R.; Dönau, F.; Frauendorf, S.; Anders, M.; Bemmerer, D.; Beyer, R.; Bhatia, C.; Birgersson, E.; Butterling, M.; Elekes, Z.; Ferrari, A.; Gooden, M. E.; Hannaske, R.; Junghans, A. R.; Kempe, M.; Kelley, J. H.; Kögler, T.; Matic, A.; Menzel, M. L.; Müller, S.; Reinhardt, T. P.; Röder, M.; Rusev, G.; Schilling, K. D.; Schmidt, K.; Schramm, G.; Tonchev, A. P.; Tornow, W.; Wagner, A.

2014-02-01

The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A =124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

Gamma-induced Positron Spectroscopy (GiPS) at a superconducting electron linear accelerator

International Nuclear Information System (INIS)

Butterling, Maik; Anwand, Wolfgang; Cowan, Thomas E.; Hartmann, Andreas; Jungmann, Marco; Krause-Rehberg, Reinhard; Krille, Arnold; Wagner, Andreas

2011-01-01

A new and unique setup for Positron Annihilation Spectroscopy has been established and optimized at the superconducting linear electron accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf (Germany). The intense, pulsed (26 MHz) photon source (bremsstrahlung with energies up to 16 MeV) is used to generate positrons by means of pair production throughout the entire sample volume. Due to the very short gamma bunches (< 5 ps temporal length), the facility for Gamma-induced Positron Spectroscopy (GiPS) is suitable for positron lifetime spectroscopy using the accelerator's radiofrequency as time reference. Positron lifetime and Doppler broadening Spectroscopy are employed by a coincident measurement (Age-Momentum Correlation) of the time-of-arrival and energy of the annihilation photons which in turn significantly reduces the background of scattered photons resulting in spectra with high signal to background ratios. Simulations of the setup using the GEANT4 framework have been performed to yield optimum positron generation rates for various sample materials and improved background conditions.

Design and first measurements of an alternative calorimetry chamber for the HZB quadrupole resonator

CERN Document Server

Keckert, Sebastian; Knobloch, Jens; Kugeler, Oliver

2015-01-01

The systematic research on superconducting thin films requires dedicated testing equipment. The Quadrupole Resonator (QPR) is a specialized tool to characterize the superconducting RF properties of circular planar samples. A calorimetric measurement of the RF surface losses allows the surface resistance to be measured with sub nano-ohm resolution. This measurement can be performed over a wide temperature and magnetic field range, at frequencies of 433, 866 and 1300 MHz. The system at Helmholtz-Zentrum Berlin (HZB) is based on a resonator built at CERN and has been optimized to lower peak electric fields and an improved resolution. In this paper the design of an alternative calorimetry chamber is presented, providing flat samples for coating which are easy changeable. All parts are connected by screwing connections and no electron beam welding is required. Furthermore this design enables exchangeability of samples between the resonators at HZB and CERN. First measurements with the new design show ambiguous r...

A novel technique for compensation of space charge effects in the LUPIN-II detector

Energy Technology Data Exchange (ETDEWEB)

Cassell, C., E-mail: cc878@uowmail.edu.au [Politecnico of Milan, Department of Energy, Via la Masa 34, 20154 Milan (Italy); University of Wollongong, Centre for Medical Physics, NSW 2522 (Australia); Ferrarini, M. [Fondazione CNAO, via Caminadella16, 20123 Milano (Italy); Rosenfeld, A. [University of Wollongong, Centre for Medical Physics, NSW 2522 (Australia); Caresana, M. [Politecnico of Milan, Department of Energy, Via la Masa 34, 20154 Milan (Italy)

2015-12-21

A new method for improving REM counter performance in Pulsed Neutron Fields (PNFs) has been developed. This method uses an analysis of the build-up of space charge in the counter to compensate for an underestimation of Ambient Dose Equivalent (H*(10)) in intense pulsed fields. It was applied to three sets of experimental data acquired using the LUPIN-II REM counter device, which is designed for use in PNFs. The data was acquired using the cyclotron at Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), at the HiRadMat facility at CERN and at the ‘Elettra Sincrotrone Trieste’ (ELETTRA), Italy. A comparison of the data with and without this compensation method is used to highlight its effectiveness. The LUPIN-II performance, which has already been shown to be able to cope with fields of up to hundreds of nSv/burst, is improved by at least one order of magnitude, with further potential for improvement.

CERN's role in medical applications

CERN Multimedia

Antonella Del Rosso

2014-01-01

Last week, CERN hosted the first meeting of the International Strategy Committee for medical applications. This Committee will help CERN establish its roadmap in the field of research and development activities for medical applications. Here the CERN Bulletin speaks with the Chair of the Committee as he shares his expectations and his vision.   Dr Michael Baumann is the Director of the Radiation Oncology department at the Carl Gustav Carus University Hospital in Dresden and of the Institute for Radiooncology of the Helmholtz-Zentrum Dresden-Rossendorf (Germany). He has recently been appointed Chair of CERN’s International Strategy Committee for medical applications – the team of experts who will advise the CERN Medical Applications Study Group led by Steve Myers. “CERN has a tremendous record in physics and basic research,” says Baumann. “I think that it has a very important role in steering some of the R&D that cannot be done at universities ...

Development of a high brightness, high current SRF photo-electron source for ERL applications

Energy Technology Data Exchange (ETDEWEB)

Neumann, Axel [Helmholtz-Zentrum Berlin (Germany); Collaboration: bERLinPro Team

2016-07-01

Energy recovery linacs (ERL) offer the potential to combine major beam properties of the two main domains of particle accelerators: The low emittance of linear accelerators and the high average beam current of storage rings, while also allowing to compress to short bunches below the ps regime. This makes among other applications ERLs an ideal candidate for future light sources. The beam properties of the ERL are given by the performance of the injection section and hence of the beam source. Helmholtz-Zentrum Berlin is currently designing and building a high average current all superconducting CW driven ERL as a prototype to demonstrate low normalized beam emittance of 1 mm*mrad at 100 mA and short pulses of about 2 ps. In this contribution we discuss the development of this class of a high brightness, high current SRF photo-electron source and present recent commissioning results. Also, alternative approaches at other laboratories are shortly reviewed.

The HMGU thoron experimental house: A new tool for exposure assessment

International Nuclear Information System (INIS)

Tschiersch, J.; Meisenberg, O.

2010-01-01

A thoron experimental house was constructed in a laboratory room of Helmholtz Zentrum Muenchen to perform exposure studies of thoron and its decay products under controlled conditions. The single room house (7.1 m 3 ) was built from unfired clay stones and clay plaster. For the plaster of the inner side, the clay was mixed with granite powder enriched with 232 Th. The thoron inventory increased by this means to about 1700 Bq and the progeny potential alpha energy to 130 μJ inside the room. The instrumentation of the experimental house includes active and passive devices for thoron and thoron decay product measurement including attached and unattached progeny, for aerosol particle number and size measurement and characterisation of the climatic conditions. Various parameters as ventilation rate and aerosol concentration can be adjusted. Experiments performed in the experimental house demonstrate the experimental power of this new tool for indoor thoron exposure assessment 2010. (authors)

Fast neutron measurements at the nELBE time-of-flight facility

Directory of Open Access Journals (Sweden)

Junghansa A. R.

2015-01-01

Full Text Available The compact neutron-time-of-flight facility nELBE at the superconducting electron accelerator ELBE of Helmholtz-Zentrum Dresden-Rossendorf has been rebuilt. A new enlarged experimental hall with a flight path of up to 10 m is available for neutron time-of-flight experiments in the fast energy range from about 50 keV to 10 MeV. nELBE is intended to deliver nuclear data of fast neutron nuclear interactions e.g. for the transmutation of nuclear waste and improvement of neutron physical simulations of innovative nuclear systems. The experimental programme consists of transmission measurements of neutron total cross sections, elastic and inelastic scattering cross section measurements, and neutron induced fission cross sections. The inelastic scattering to the first few excited states in 56Fe was investigated by measuring the gamma production cross section with an HPGe detector. The neutron induced fission of 242Pu was studied using fast ionisation chambers with large homogeneous actinide deposits.

Gamma-induced Positron Spectroscopy (GiPS) at a superconducting electron linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Butterling, Maik, E-mail: maik.butterling@googlemail.com [Martin-Luther University, Dept. of Physics, 06099 Halle (Germany); Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Anwand, Wolfgang; Cowan, Thomas E.; Hartmann, Andreas [Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Jungmann, Marco; Krause-Rehberg, Reinhard [Martin-Luther University, Dept. of Physics, 06099 Halle (Germany); Krille, Arnold; Wagner, Andreas [Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

2011-11-15

A new and unique setup for Positron Annihilation Spectroscopy has been established and optimized at the superconducting linear electron accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf (Germany). The intense, pulsed (26 MHz) photon source (bremsstrahlung with energies up to 16 MeV) is used to generate positrons by means of pair production throughout the entire sample volume. Due to the very short gamma bunches (< 5 ps temporal length), the facility for Gamma-induced Positron Spectroscopy (GiPS) is suitable for positron lifetime spectroscopy using the accelerator's radiofrequency as time reference. Positron lifetime and Doppler broadening Spectroscopy are employed by a coincident measurement (Age-Momentum Correlation) of the time-of-arrival and energy of the annihilation photons which in turn significantly reduces the background of scattered photons resulting in spectra with high signal to background ratios. Simulations of the setup using the GEANT4 framework have been performed to yield optimum positron generation rates for various sample materials and improved background conditions.

Nuclear deformation and neutron excess as competing effects for dipole strength in the pygmy region.

Science.gov (United States)

Massarczyk, R; Schwengner, R; Dönau, F; Frauendorf, S; Anders, M; Bemmerer, D; Beyer, R; Bhatia, C; Birgersson, E; Butterling, M; Elekes, Z; Ferrari, A; Gooden, M E; Hannaske, R; Junghans, A R; Kempe, M; Kelley, J H; Kögler, T; Matic, A; Menzel, M L; Müller, S; Reinhardt, T P; Röder, M; Rusev, G; Schilling, K D; Schmidt, K; Schramm, G; Tonchev, A P; Tornow, W; Wagner, A

2014-02-21

The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A=124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

Stability of a modified Peaceman–Rachford method for the paraxial Helmholtz equation on adaptive grids

Energy Technology Data Exchange (ETDEWEB)

Sheng, Qin, E-mail: Qin_Sheng@baylor.edu [Department of Mathematics and Center for Astrophysics, Space Physics and Engineering Research, Baylor University, One Bear Place, Waco, TX 76798-7328 (United States); Sun, Hai-wei, E-mail: hsun@umac.mo [Department of Mathematics, University of Macau (Macao)

2016-11-15

This study concerns the asymptotic stability of an eikonal, or ray, transformation based Peaceman–Rachford splitting method for solving the paraxial Helmholtz equation with high wave numbers. Arbitrary nonuniform grids are considered in transverse and beam propagation directions. The differential equation targeted has been used for modeling propagations of high intensity laser pulses over a long distance without diffractions. Self-focusing of high intensity beams may be balanced with the de-focusing effect of created ionized plasma channel in the situation, and applications of grid adaptations are frequently essential. It is shown rigorously that the fully discretized oscillation-free decomposition method on arbitrary adaptive grids is asymptotically stable with a stability index one. Simulation experiments are carried out to illustrate our concern and conclusions.

Kelvin-Helmholtz instability and kinetic internal kink modes in tokamaks

International Nuclear Information System (INIS)

Naitou, H.; Kobayashi, T.; Yagi, M.; Matsumoto, T.; Tokuda, S.; Kishimoto, Y.

2003-01-01

The m=1 (poloidal mode number) and n=1 (toroidal mode number) kinetic internal kink (KIK) mode in the presence of a density gradient is studied with the cylindrical version of the gyro-reduced MHD code, which is one of the extended MHD codes being able to treat the physics beyond resistive MHD. Electron inertia and electron finite temperature effects are included. The unstable KIK mode is observed in the parameter range in which the linear theory predicts complete stabilization due to the electron diamagnetic effect. The electrostatic potential profile in the linear stage of the KIK instability has the sheared poloidal flow with the m=1 mode structure. The vortexes are generated due to the Kelvin-Helmholtz (K-H) instability. The KIK is stabilized when the vortexes are formed, but it is destabilized again as the vortexes diminish due to the charge neutralizing electron motion along the magnetic field. These phenomena are observed in the early nonlinear stage of the KIK instability in which the width of the m=1 magnetic island is sufficiently small compared with the radial extent of the vortexes. The strong coupling between the vortexes and the KIK instability can be one of the candidates explaining the sudden onset of the sawtooth crash. (author)

Kelvin-Helmholtz instability in type-1 comet tails and associated phenomena

International Nuclear Information System (INIS)

Ershkovich, A.I.

1980-01-01

Selected problems of the solar wind - comet tail coupling that are currently accessible to quantitative analysis are reviewed. The model of a comet tail as a plasma cylinder separated by a tangential discontinuity surface from the solar wind is discussed in detail. This model is compatible with the well-known Alfven mechanism of formation of the comet tail. The stability problem of the comet tail boundary (considered as a discontinuity surface) is solved. Under typical conditions a comet tail boundary can undergo the Kelvin-Helmholtz instability. With finite amplitude the stabilizing effect of the magnetic field increases, and waves become stabilized. This model supplies a detailed quantitative description of helical waves observed in type-1 comet tails. A more general model of the tail boundary as a transition layer with a continuous change of the plasma parameters within it is also considered. This theory, in principle, enables us to solve one of the fundamental problems of cometary physics: the magnetic field of the comet tail can be derived from the observations of helical waves. This field turns out to be of the order of the interplanetary field. Various other considerations, discussed in this review also support this conclusion. (orig.)

Magnetohydrodynamic Kelvin-Helmholtz instabilities in astrophysics. 3. Hydrodynamic flows with shear layers

Energy Technology Data Exchange (ETDEWEB)

Ferraro, A [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany, F.R.)); Massaglia, S [Turin Univ. (Italy). Ist. di Fisica; Trussoni, E [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica

1982-03-01

In this paper a discussion is presented on Kelvin-Helmholtz instabilities in pressure-confined two-dimensional flows (slabs) delimited by boundary layers with velocity and density gradients. It is found that the fastest growing modes in supersonic flows are produced by perturbations reflecting at the boundaries and have wavelengths of the order of the slab width; this peak of instability is even more evident than in the case of vortex-sheet cylindrical flows, discussed in a previous paper. From a comparison of the results for the two-dimensional slab and three-dimensional cylinder it is concluded that a two-dimensional treatment provides an adequate description of instabilities in fluid flows. In this analogy, symmetric and antisymmetric modes in the slab correspond to pinching and helical modes in the cylinder. In the final section a comparison is attempted of the results obtained with morphologies in collimated jets in extragalactic radio sources; general characteristics appear to be classifiable in terms of scale-lengths of the velocity and density gradients in the boundary layers.

Annual report 2011. Institute of Ion Beam Physics and Materials Research

Energy Technology Data Exchange (ETDEWEB)

Cordeiro, A.L.; Fassbender, J.; Heera, V.; Helm, M. (eds.)

2012-08-22

The first year of membership of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in the Helmholtz Association of German Research Centers (HGF) was a year of many changes also for the Institute of Ion Beam Physics and Materials Research (IIM). The transition period, however, is not yet over, since the full integration of the Center into the HGF will only be completed in the next period of the so-called program-oriented funding (POF). This funding scheme addresses the six core research fields identified by the Helmholtz Association (Energy; Earth and Environment; Health; Key Technologies; Structure of Matter; Aeronautics, Space and Transport) to deal with the grand challenges faced by society, science and industry. Since the Institute has strong contributions to both core fields ''Key Technologies'' and ''Structure of Matter'', intense discussions were held amongst the leading scientists of the Institute, across the Institutes of the HZDR, and finally with leading scientists of other Helmholtz centers, to determine the most appropriate classification of the Institute's research. At the end we decided to establish ourselves in Structure of Matter, the core field in which most of the large-scale photon, neutron and ion facilities in Germany are located. As a consequence, the Ion Beam Center (IBC) of the Institute submitted an application to become a HGF recognized large-scale facility, providing more than 50% of its available beam time to external users. This application perfectly reflects the development of the IBC over more than a decade as a European Union funded infrastructure in the framework of the projects ''Center for Application of Ion Beams in Materials Research (AIM)'' (1998-2000, 2000-2003, 2006-2010) and subsequently as the coordinator of the integrated infrastructure initiative (I3) ''Support of Public and Industrial Research using Ion Beam Technology (SPIRIT)'' (2009

Cold and heat storage in downtown Berlin; Kaelte und Waermespeicherung im Zentrum Berlins

Energy Technology Data Exchange (ETDEWEB)

Seibt, P; Brandt, W; Kabus, F; Moellmann, G; Poppei, J [Geothermie Neubrandenburg GmbH (Germany)

1997-12-01

The concept of energy supply for the seat of the German Parliament is based on self-sufficiency by using motor-driven district heating power stations. Esterified vegetable oil (bio-diesel) serves as fuel. These motor-driven power stations are operated depending on the amount of power required actually. The heat energy which is released when generating power at the temperature level >100 C - which is favourable for heating purposes - serves directly for heat supply or the driving a refrigerating machine/heat pump for the supply of cooling energy in summer and low-temperature heat in winter. As the demand on heat and power supply often will not be parallel, there will be a temporary surplus of heat offered by the motor-driven power station, and at other times it will be deficient. That is why surplus heat from the motor-driven power station is stored in a deep aquifer heat reservoir for recovery and utilisation for heating in winter. By using a geothermal saline water reservoir, the waste heat from the motor-driven power station can be fed into it at a temperature level ranging from 60.. 80 C and recovered and utilised at a temperature level ranging from 60.. 20 C. A shallow groundwater aquifer cold storing reservoir serves for cooling: the cold stored in winter is supplied in summer to the cooling equipment of the building by direct cooling with the cold water form the aquifer (heat exchange) at a temperature level of 14/15 C. The cooling demand in case of air dehumidification at a temperature level of 6/12 C is covered by a cooling machine which is also cooled with the cold water from the aquifer. As cooling machine/heat pump an environment-friendly, CFC-free absorption machine is used working on a combination of water and lithium bromide. The machine is driven by the waste heat from the motor-driven power plant. (orig.) [Deutsch] Im Zentrum des Systems der Energieversorgung der Parlamentsbauten steht die autarke Energiebereitstellung durch den Einsatz von

Double-reconnected magnetic structures driven by Kelvin-Helmholtz vortices at the Earth's magnetosphere

International Nuclear Information System (INIS)

Borgogno, D.; Califano, F.; Pegoraro, F.; Faganello, M.

2015-01-01

In an almost collisionless magnetohydrodynamic plasma in a relatively strong magnetic field, stresses can be conveyed far from the region where they are exerted, e.g., through the propagation of Alfvèn waves. The forced dynamics of line-tied magnetic structures in solar and stellar coronae (see, e.g., A. F. Rappazzo and E. N. Parker, Astrophys. J. 773, L2 (2013) and references therein) is a paradigmatic case. Here, we investigate how this action at a distance develops from the equatorial region of the Kelvin-Helmholtz unstable flanks of the Earth's magnetosphere leading to the onset, at mid latitude in both hemispheres, of correlated double magnetic field line reconnection events that can allow the solar wind plasma to enter the Earth's magnetosphere

Extracting the potential-well of a near-field optical trap using the Helmholtz-Hodge decomposition

Science.gov (United States)

Zaman, Mohammad Asif; Padhy, Punnag; Hansen, Paul C.; Hesselink, Lambertus

2018-02-01

The non-conservative nature of the force field generated by a near-field optical trap is analyzed. A plasmonic C-shaped engraving on a gold film is considered as the trap. The force field is calculated using the Maxwell stress tensor method. The Helmholtz-Hodge decomposition is used to extract the conservative and the non-conservative component of the force. Due to the non-negligible non-conservative component, it is found that the conventional approach of extracting the potential by direct integration of the force is not accurate. Despite the non-conservative nature of the force field, it is found that the statistical properties of a trapped nanoparticle can be estimated from the conservative component of the force field alone. Experimental and numerical results are presented to support the claims.

Bringing new archival sources to Wundt scholarship: the case of Wundt's assistantship with Helmholtz.

Science.gov (United States)

Araujo, Saulo de Freitas

2014-02-01

Wilhelm Wundt's biography is one of the main domains in Wundt scholarship that deserves more detailed attention. The few existing biographical works present many problems, ranging from vagueness to chronological inaccuracies, among others. One of the important gaps concerns the so-called Heidelberg period (1852-1874), during which he went from being a medical student to holding a professorship at the University of Heidelberg. The aim of this article is to dispel a very common confusion in the secondary literature, which refers to Wundt's assistantship with Helmholtz at the Physiological Institute, by establishing the precise dates of his assistantship. Contrary to what is generally repeated in the secondary literature, the primary sources allow us to determine precisely this period from October 1858 to March 1865. I conclude by pointing out the indispensability of the primary sources not only to Wundt scholarship but also to the historiography of psychology in general.

The evolution of a localized nonlinear wave of the Kelvin-Helmholtz instability with gravity

Science.gov (United States)

Orazzo, Annagrazia; Hoepffner, Jérôme

2012-11-01

At the interface between two fluids of different density and in the presence of gravity, there are well known periodic surface waves which can propagate for long distances with little attenuation, as it is for instance the case at the surface of the sea. If wind is present, these waves progressively accumulate energy as they propagate and grow to large sizes—this is the Kelvin-Helmholtz instability. On the other hand, we show in this paper that for a given wind strength, there is potential for the growth of a localized nonlinear wave. This wave can reach a size such that the hydrostatic pressure drop from top to bottom equals the stagnation pressure of the wind. This process for the disruption of the flat interface is localized and nonlinear. We study the properties of this wave using numerical simulations of the Navier-Stokes equations.

An Investigation of Hall Currents Associated with Tripolar Magnetic Fields During Magnetospheric Kelvin Helmholtz Waves

Science.gov (United States)

Sturner, A. P.; Eriksson, S.; Newman, D. L.; Lapenta, G.; Gershman, D. J.; Plaschke, F.; Ergun, R.; Wilder, F. D.; Torbert, R. B.; Giles, B. L.; Strangeway, R. J.; Russell, C. T.; Burch, J. L.

2016-12-01

Kinetic simulations and observations of magnetic reconnection suggest the Hall term of Ohm's Law is necessary for understanding fast reconnection in the Earth's magnetosphere. During high (>1) guide field plasma conditions in the solar wind and in Earth's magnetopause, tripolar variations in the guide magnetic field are often observed during current sheet crossings, and have been linked to reconnection Hall magnetic fields. Two proposed mechanisms for these tripolar variations are the presence of multiple nearby X-lines and magnetic island coalescence. We present results of an investigation into the structure of the electron currents supporting tripolar guide magnetic field variations during Kelvin-Helmholtz wave current sheet crossings using the Magnetosphere Multiscale (MMS) Mission, and compare with bipolar magnetic field structures and with kinetic simulations to understand how these tripolar structures may be used as tracers for magnetic islands.

ESTUDO DA INSTABILIDADE KELVIN-HELMHOLTZ ATRAVÉS DE SIMULAÇÕES COM O CÓDIGO ATHENA

Directory of Open Access Journals (Sweden)

Priscila Freitas-Lemes

2013-12-01

Full Text Available As instabilidades Kelvin-Helmholtz são comuns em sistemas astrofísicos e vão desde jatos deburacos negros até disco de acreção protoplantário. Um objeto astrofísico com fortes características da instabilidade de Kelvin-Helmholtz é a Nebulosa de Caraguejo, na qual a expansão do material foi ocasionado pela explosão de uma supernova há, aproximadamente, 1000 anos. Essa instabilidade ocorre no limite entre dois fluidos de diferentes densidades, quando um dos fluidos é acelerado com relação ao outro. Com o objetivo de estudar essa instabilidade, realizamos uma simulação com o código de malha euleriana ATHENA. Para essasimulação, consideramos um domínio quadrado com limites periódicos sobre as laterais, e, refletindo na fronteirada parte superior e inferior. A região superior da caixa é preenchida com um gás de densidade ρ=1,0, pressãoP1=1,0, índice adiabático γ=5/3 e velocidade u1=0,03 na direção x (para direita. A parte inferior tem densidadeρ=2,0, mesma pressão, velocidade e índice adiabático, só que no sentido contrário, para a esquerda. A velocidade é definida como uma função senoidal, que cria a perturbação inicial. Como resultado, observamos o princípio da instabilidade e a formação dos vórtices, com as cristas bem definidas. A nitidez da fronteira entre o material de alta e de baixa densidade está bem conservada, devido à difusão relativamente baixa do algoritmo. Notamos, ainda, que, evoluindo a simulação, os vórtices formados a partir da turbulência fundem-se.

Observation of the Kelvin–Helmholtz Instability in a Solar Prominence

Science.gov (United States)

Yang, Heesu; Xu, Zhi; Lim, Eun-Kyung; Kim, Sujin; Cho, Kyung-Suk; Kim, Yeon-Han; Chae, Jongchul; Cho, Kyuhyoun; Ji, Kaifan

2018-04-01

Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical or thermal instabilities. Such instabilities are important because they may be responsible for energy transport and conversion. We present a clear observation of a streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place in a solar prominence using the Hα Lyot filter installed at the New Vacuum Solar Telescope, Fuxian-lake Solar Observatory in Yunnan, China. On one side of the prominence, a series of plasma blobs floated up from the chromosphere and streamed parallel to the limb. The plasma stream was accelerated to about 20–60 km s‑1 and then undulated. We found that 2″- and 5″-size vortices formed, floated along the stream, and then broke up. After the 5″-size vortex, a plasma ejection out of the stream was detected in the Solar Dynamics Observatory/Atmospheric Imaging Assembly images. Just before the formation of the 5″-size vortex, the stream displayed an oscillatory transverse motion with a period of 255 s with the amplitude growing at the rate of 0.001 s‑1. We attribute this oscillation of the stream and the subsequent formation of the vortex to the KHI triggered by velocity shear between the stream, guided by the magnetic field and the surrounding media. The plasma ejection suggests the transport of prominence material into the upper layer by the KHI in its nonlinear stage.

Cluster observations of reconnection due to the Kelvin-Helmholtz instability at the dawnside magnetospheric flank

Directory of Open Access Journals (Sweden)

K. Nykyri

2006-10-01

Full Text Available On 3 July 2001, the four Cluster satellites traversed along the dawnside magnetospheric flank and observed large variations in all plasma parameters. The estimated magnetopause boundary normals were oscillating in the z-direction and the normal component of the magnetic field showed systematic  2–3 min bipolar variations for 1 h when the IMF had a small positive b_z-component and a Parker-spiral orientation in the x,y-plane. Brief  33 s intervals with excellent deHoffman Teller frames were observed satisfying the Walén relation. Detailed comparisons with 2-D MHD simulations indicate that Cluster encountered rotational discontinuities generated by Kelvin-Helmholtz instability. We estimate a wave length of  6 R_E and a wave vector with a significant z-component.

Progress toward Kelvin-Helmholtz instabilities in a High-Energy-Density Plasma on the Nike laser

Science.gov (United States)

Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Huntington, C. M.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Plewa, T.; Dwarkadas, V. V.

2008-04-01

In the realm of high-energy-density (HED) plasmas, there exist three primary hydrodynamic instabilities of concern: Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH). Although the RT and the RM instabilities have been readily observed and diagnosed in the laboratory, the KH instability remains relatively unexplored in HED plasmas. Unlike the RT and RM instabilities, the KH instability is driven by a lifting force generated by a strong velocity gradient in a stratified fluid. Understanding the KH instability mechanism in HED plasmas will provide essential insight into oblique shock systems, jets, mass stripping, and detailed RT-spike development. In addition, our KH experiment will help provide the groundwork for future transition to turbulence experiments. We present 2D FLASH simulations and experimental data from our initial attempts to create a pure KH system using the Nike laser at the Naval Research Laboratory.

Annual report 2015. Institute of Resource Ecology

International Nuclear Information System (INIS)

Stumpf, Thorsten

2016-01-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Thus, all scientific work of the IRE belongs to the research field ''Energy'' of the HGF. The research objective is the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks ensued by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2016. Institute of Resource Ecology

International Nuclear Information System (INIS)

Stumpf, Thorsten; Foerstendorf, Harald; Bok, Frank; Richter, Anke

2017-01-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden - Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Overview of nanoscale NEXAFS performed with soft X-ray microscopes

Directory of Open Access Journals (Sweden)

Peter Guttmann

2015-02-01

Full Text Available Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM as well as full-field transmission X-ray microscopes (TXM allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

Using McStas for modelling complex optics, using simple building bricks

International Nuclear Information System (INIS)

Willendrup, Peter K.; Udby, Linda; Knudsen, Erik; Farhi, Emmanuel; Lefmann, Kim

2011-01-01

The McStas neutron ray-tracing simulation package is a versatile tool for producing accurate neutron simulations, extensively used for design and optimization of instruments, virtual experiments, data analysis and user training. In McStas, component organization and simulation flow is intrinsically linear: the neutron interacts with the beamline components in a sequential order, one by one. Historically, a beamline component with several parts had to be implemented with a complete, internal description of all these parts, e.g. a guide component including all four mirror plates and required logic to allow scattering between the mirrors. For quite a while, users have requested the ability to allow 'components inside components' or meta-components, allowing to combine functionality of several simple components to achieve more complex behaviour, i.e. four single mirror plates together defining a guide. We will here show that it is now possible to define meta-components in McStas, and present a set of detailed, validated examples including a guide with an embedded, wedged, polarizing mirror system of the Helmholtz-Zentrum Berlin type.

Light ion production for a future radiobiological facility at CERN: preliminary studies.

Science.gov (United States)

Stafford-Haworth, Joshua; Bellodi, Giulia; Küchler, Detlef; Lombardi, Alessandra; Röhrich, Jörg; Scrivens, Richard

2014-02-01

Recent medical applications of ions such as carbon and helium have proved extremely effective for the treatment of human patients. However, before now a comprehensive study of the effects of different light ions on organic targets has not been completed. There is a strong desire for a dedicated facility which can produce ions in the range of protons to neon in order to perform this study. This paper will present the proposal and preliminary investigations into the production of light ions, and the development of a radiobiological research facility at CERN. The aims of this project will be presented along with the modifications required to the existing linear accelerator (Linac3), and the foreseen facility, including the requirements for an ion source in terms of some of the specification parameters and the flexibility of operation for different ion types. Preliminary results from beam transport simulations will be presented, in addition to some planned tests required to produce some of the required light ions (lithium, boron) to be conducted in collaboration with the Helmholtz-Zentrum für Materialien und Energie, Berlin.

Small-angle X-ray scattering (SAXS) for metrological size determination of nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Gleber, Gudrun; Krumrey, Michael; Cibik, Levent; Marggraf, Stefanie; Mueller, Peter [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Hoell, Armin [Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany)

2011-07-01

To measure the size of nanoparticles, different measurement methods are available but their results are often not compatible. In the framework of an European metrology project we use Small-Angle X-ray Scattering (SAXS) to determine the size and size distribution of nanoparticles in aqueous solution, where the special challange is the traceability of the results. The experiments were performed at the Four-Crystal Monochromator (FCM) beamline in the laboratory of Physikalisch-Technische Bundesanstalt (PTB) at BESSY II using the SAXS setup of the Helmholtz-Zentrum Berlin (HZB). We measured different particles made of PMMA and gold in a diameter range of 200 nm down to about 10 nm. The aspects of traceability can be classified in two parts: the first is the experimental part with the uncertainties of distances, angles, and wavelength, the second is the part of analysis, with the uncertainty of the choice of the model used for fitting the data. In this talk we want to show the degree of uncertainty, which we reached in this work yet.

Intercomparison of radiation protection instrumentation in a pulsed neutron field

CERN Document Server

Caresana, M; Esposito, A; Ferrarini, M; Golnik, N; Hohmann, E; Leuschner, A; Luszik-Bhadra, M; Manessi, G; Mayer, S; Ott, K; Röhrich, J; Silari, M; Trompier, F; Volnhals, M; Wielunski, M

2014-01-01

In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instru...

Experiments on the formation of titanium-44 in supernovae; Experimente zur Entstehung von Titan-44 in Supernovae

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Konrad

2012-11-01

In this thesis the astrophysically interesting resonance triplet of the {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction at 4.5 MeV has been studied. For this purpose energies of proton and {alpha} beams provided by 3 MV Tandetron at Helmholtz-Zentrum Dresden-Rossendorf have been calibrated. Excitation functions of energy regions near the resonances and in-beam spectra of four different targets have been measured. The {sup 40}Ca(p,{gamma}){sup 41}Sc reaction has been used to scan the structure of the activated targets. Afterwards their activity has been measured in the underground laboratory Felsenkeller Dresden. Hence the sum of resonance strengths at laboratory {alpha} energies of 4497 and 4510 keV of (12.8{+-}2.3) eV has been determined as well as the sum of the total triplet strength, including 4523 keV, of (12.0{+-}2.0) eV. In the case of the first resonance, the uncertainty was decreased from 19% to 18 %. Furthermore the results of this work establish a basis for reaching much lower uncertainties in the future.

Overview of nanoscale NEXAFS performed with soft X-ray microscopes.

Science.gov (United States)

Guttmann, Peter; Bittencourt, Carla

2015-01-01

Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS) spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM) as well as full-field transmission X-ray microscopes (TXM) allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB) at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

Understanding Kelvin-Helmholtz instability in paraffin-based hybrid rocket fuels

Science.gov (United States)

Petrarolo, Anna; Kobald, Mario; Schlechtriem, Stefan

2018-04-01

Liquefying fuels show higher regression rates than the classical polymeric ones. They are able to form, along their burning surface, a low viscosity and surface tension liquid layer, which can become unstable (Kelvin-Helmholtz instability) due to the high velocity gas flow in the fuel port. This causes entrainment of liquid droplets from the fuel surface into the oxidizer gas flow. To better understand the droplets entrainment mechanism, optical investigations on the combustion behaviour of paraffin-based hybrid rocket fuels in combination with gaseous oxygen have been conducted in the framework of this research. Combustion tests were performed in a 2D single-slab burner at atmospheric conditions. High speed videos were recorded and analysed with two decomposition techniques. Proper orthogonal decomposition (POD) and independent component analysis (ICA) were applied to the scalar field of the flame luminosity. The most excited frequencies and wavelengths of the wave-like structures characterizing the liquid melt layer were computed. The fuel slab viscosity and the oxidizer mass flow were varied to study their influence on the liquid layer instability process. The combustion is dominated by periodic, wave-like structures for all the analysed fuels. Frequencies and wavelengths characterizing the liquid melt layer depend on the fuel viscosity and oxidizer mass flow. Moreover, for very low mass flows, no wavelength peaks are detected for the higher viscosity fuels. This is important to better understand and predict the onset and development of the entrainment process, which is connected to the amplification of the longitudinal waves.

Perception and Neural Coding of Harmonic Fusion in Ferrets

Science.gov (United States)

2004-01-01

distinct percepts that come under the rubric of pitch, be- cause periodicity pitch underlies speakers’ voices and speech prosody, as well as musical ...spectral fusion is unclear for sounds having predominantly low-frequency spectra such as speech, music , and many animal vocalizations. In summary...84, 560–565. von Helmholtz, H. (1863). Die Lehre von den Tonempfindungen als physiologische Grundlage fr die Theorie der Musik . (Vieweg und Sohn

Spatial distribution of rolled up Kelvin-Helmholtz vortices at Earth's dayside and flank magnetopause

Directory of Open Access Journals (Sweden)

M. G. G. T. Taylor

2012-06-01

Full Text Available The Kelvin-Helmholtz Instability (KHI can drive waves at the magnetopause. These waves can grow to form rolled-up vortices and facilitate transfer of plasma into the magnetosphere. To investigate the persistence and frequency of such waves at the magnetopause we have carried out a survey of all Double Star 1 magnetopause crossings, using a combination of ion and magnetic field measurements. Using criteria originally used in a Geotail study made by Hasegawa et al. (2006 (forthwith referred to as H2006, 17 candidate events were identified from the entire TC-1 mission (covering ~623 orbits where the magnetopause was sampled, a majority of which were on the dayside of the terminator. The relationship between density and shear velocity was then investigated, to identify the predicted signature of a rolled up vortex from H2006 and all 17 events exhibited some level of rolled up behavior. The location of the events had a clear dawn-dusk asymmetry, with 12 (71% on the post noon, dusk flank suggesting preferential growth in this region.

A new chapter in doctoral candidate training: The Helmholtz Space Life Sciences Research School (SpaceLife)

Science.gov (United States)

Hellweg, C. E.; Gerzer, R.; Reitz, G.

2011-05-01

In the field of space life sciences, the demand of an interdisciplinary and specific training of young researchers is high due to the complex interaction of medical, biological, physical, technical and other questions. The Helmholtz Space Life Sciences Research School (SpaceLife) offers an excellent interdisciplinary training for doctoral students from different fields (biology, biochemistry, biotechnology, physics, psychology, nutrition or sports sciences and related fields) and any country. SpaceLife is coordinated by the Institute of Aerospace Medicine at the German Aerospace Center (DLR) in Cologne. The German Universities in Kiel, Bonn, Aachen, Regensburg, Magdeburg and Berlin, and the German Sports University (DSHS) in Cologne are members of SpaceLife. The Universities of Erlangen-Nürnberg, Frankfurt, Hohenheim, and the Beihang University in Beijing are associated partners. In each generation, up to 25 students can participate in the three-year program. Students learn to develop integrated concepts to solve health issues in human spaceflight and in related disease patterns on Earth, and to further explore the requirements for life in extreme environments, enabling a better understanding of the ecosystem Earth and the search for life on other planets in unmanned and manned missions. The doctoral candidates are coached by two specialist supervisors from DLR and the partner university, and a mentor. All students attend lectures in different subfields of space life sciences to attain an overview of the field: radiation and gravitational biology, astrobiology and space physiology, including psychological aspects of short and long term space missions. Seminars, advanced lectures, laboratory courses and stays at labs at the partner institutions or abroad are offered as elective course and will provide in-depth knowledge of the chosen subfield or allow to appropriate innovative methods. In Journal Clubs of the participating working groups, doctoral students learn

A new relativistic viscous hydrodynamics code and its application to the Kelvin-Helmholtz instability in high-energy heavy-ion collisions

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Kazuhisa [Nagoya University, Department of Physics, Nagoya (Japan); Nonaka, Chiho [Nagoya University, Department of Physics, Nagoya (Japan); Nagoya University, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya (Japan); Duke University, Department of Physics, Durham, NC (United States)

2017-06-15

We construct a new relativistic viscous hydrodynamics code optimized in the Milne coordinates. We split the conservation equations into an ideal part and a viscous part, using the Strang spitting method. In the code a Riemann solver based on the two-shock approximation is utilized for the ideal part and the Piecewise Exact Solution (PES) method is applied for the viscous part. We check the validity of our numerical calculations by comparing analytical solutions, the viscous Bjorken's flow and the Israel-Stewart theory in Gubser flow regime. Using the code, we discuss possible development of the Kelvin-Helmholtz instability in high-energy heavy-ion collisions. (orig.)

A new relativistic viscous hydrodynamics code and its application to the Kelvin-Helmholtz instability in high-energy heavy-ion collisions

Science.gov (United States)

Okamoto, Kazuhisa; Nonaka, Chiho

2017-06-01

We construct a new relativistic viscous hydrodynamics code optimized in the Milne coordinates. We split the conservation equations into an ideal part and a viscous part, using the Strang spitting method. In the code a Riemann solver based on the two-shock approximation is utilized for the ideal part and the Piecewise Exact Solution (PES) method is applied for the viscous part. We check the validity of our numerical calculations by comparing analytical solutions, the viscous Bjorken's flow and the Israel-Stewart theory in Gubser flow regime. Using the code, we discuss possible development of the Kelvin-Helmholtz instability in high-energy heavy-ion collisions.

AGF activieties in the field of systems analysis and technology assessment

International Nuclear Information System (INIS)

1983-01-01

Activities of the following West German organisation in the field of systems analysis are reviewed: Kernforschungsanlage Juelich (KFA), Kernforschungszentrum Karlsruhe (KfK), Deutsche Forschungs- und Versuchsanstalt fuer Luft- und Raumfahrt (DFVLR), Gesellschaft fuer Strahlen- und Umweltforschung (GSF), Gesellschaft fuer Mathematik und Datenverarbeitung (GMD), Max-Planck-Institut fuer Plasmaphysik (IPP). (UA) [de

Helmholtz Natural Modes: the universal and discrete spatial fabric of electromagnetic wavefields

International Nuclear Information System (INIS)

El Gawhary, Omar

2017-01-01

The interaction of electromagnetic waves with matter is at the foundation of the way we perceive and explore the world around us. In fact, when a field interacts with an object, signatures on the object’s geometry and physical properties are recorded in the resulting scattered field and are transported away from the object, where they can eventually be detected and processed. An optical field can transport information through its spectral content, its polarization state, and its spatial distribution. Generally speaking, the field’s spatial structure is typically subjected to changes under free-space propagation and any information therein encoded gets reshuffled by the propagation process. We must ascribe to this fundamental reason the fact that spectroscopy was known to the ancient civilizations already, and founded as modern science in the middle of seventeenth century, while to date we do not have an established scientific of field of ‘spatial spectroscopy’ yet. In this work we tackle this issue and we show how any field, whose evolution is dictated by Helmholtz equation, contains a universal and invariant spatial structure. When expressed in the framework of this spatial fabric, the spatial information content carried by any field reveals its invariant nature. This opens the way to novel paradigms in optical digital communications, inverse scattering, materials inspection, nanometrology and quantum optics. (paper)

MESSENGER Orbital Observations of Large-Amplitude Kelvin-Helmholtz Waves at Mercury's Magnetopause

Science.gov (United States)

Sundberg, Torbjorn; Boardsen, Scott A.; Slavin, James A.; Anderson, Brian J.; Korth, Haje; Zurbuchen, Thomas H.; Raines, Jim M.; Solomon, Sean C.

2012-01-01

We present a survey of Kelvi\\ n-Helmholtz (KH) waves at Mercury's magnetopause during MESSENGER's first Mercury year in orb it. The waves were identified on the basis of the well-established sawtooth wave signatures that are associated with non-linear KH vortices at the magnetopause. MESSENGER frequently observed such KH waves in the dayside region of the magnetosphere where the magnetosheath flow velocity is still sub -sonic, which implies that instability growth rates at Mercury's magnetopau are much larger than at Earth. We attribute these greater rates to the limited wave energy dissipation in Mercury's highly resistive regolith. The wave amplitude was often on the order of ' 00 nT or more, and the wave periods were - 10- 20 s. A clear dawn-dusk asymmetry is present in the data, in that all of the observed wave events occurred in the post-noon and dusk-side sectors of the magnetopause. This asymmetry is like ly related to finite Larmor-radius effects and is in agreement with results from particle-in-cell simulations of the instability. The waves were observed almost exclusively during periods when the north-south component of the magnetosheath magnetic field was northward, a pattern similar to that for most terrestrial KH wave events. Accompanying plasma measurements show that the waves were associated with the transport of magnetosheath plasma into the magnetosphere.

Microcanonical-ensemble computer simulation of the high-temperature expansion coefficients of the Helmholtz free energy of a square-well fluid

Science.gov (United States)

Sastre, Francisco; Moreno-Hilario, Elizabeth; Sotelo-Serna, Maria Guadalupe; Gil-Villegas, Alejandro

2018-02-01

The microcanonical-ensemble computer simulation method (MCE) is used to evaluate the perturbation terms Ai of the Helmholtz free energy of a square-well (SW) fluid. The MCE method offers a very efficient and accurate procedure for the determination of perturbation terms of discrete-potential systems such as the SW fluid and surpass the standard NVT canonical ensemble Monte Carlo method, allowing the calculation of the first six expansion terms. Results are presented for the case of a SW potential with attractive ranges 1.1 ≤ λ ≤ 1.8. Using semi-empirical representation of the MCE values for Ai, we also discuss the accuracy in the determination of the phase diagram of this system.

Annual report 2014. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Thorsten (ed.)

2015-07-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden - Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and nonradioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants, and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes, and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2015. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Thorsten (ed.)

2016-07-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Thus, all scientific work of the IRE belongs to the research field ''Energy'' of the HGF. The research objective is the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks ensued by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2016. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Foerstendorf, Harald; Bok, Frank; Richter, Anke (eds.) [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

2017-06-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden - Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2014. Institute of Resource Ecology

International Nuclear Information System (INIS)

Stumpf, Thorsten

2015-01-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden - Rossendorf (HZDR). The research activities are mainly integrated into the program ''Nuclear Waste Management, Safety and Radiation Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. We investigate the ecological risks exerted by radioactive and nonradioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants, and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level by using advanced spectroscopic methods. This in turn enables us to assess the macroscopic phenomena, including models, codes, and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2013. Institute of Resource Ecology

International Nuclear Information System (INIS)

Stumpf, Thorsten

2013-01-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The Research activities are mainly integrated into the program ''Nuclear Safety Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. Namely, we investigate the ecological risks exerted by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Annual report 2013. Institute of Resource Ecology

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Thorsten (ed.)

2013-07-01

The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The Research activities are mainly integrated into the program ''Nuclear Safety Research (NUSAFE)'' of the Helmholtz Association (HGF) and focused on the topics ''Safety of Nuclear Waste Disposal'' and ''Safety Research for Nuclear Reactors''. Additionally, various activities have been started investigating chemical and environmental aspects of processing and recycling of strategic metals, namely rare earth elements. These activities are located in the HGF program ''Energy Efficiency, Materials and Resources (EMR)''. Both programs, and therefore all work which is done at IRE, belong to the research sector ''Energy'' of the HGF. The research objectives are the protection of humans and the environment from hazards caused by pollutants resulting from technical processes that produce energy and raw materials. Treating technology and ecology as a unity is the major scientific challenge in assuring the safety of technical processes and gaining their public acceptance. Namely, we investigate the ecological risks exerted by radioactive and non-radioactive metals in the context of nuclear waste disposal, the production of energy in nuclear power plants and in processes along the value chain of metalliferous raw materials. A common goal is to generate better understanding about the dominating processes essential for metal mobilization and immobilization on the molecular level. This in turn enables us to assess the macroscopic phenomena, including models, codes and data for predictive calculations, which determine the transport and distribution of contaminants in the environment.

Nonlinear aeroacoustic characterization of Helmholtz resonators with a local-linear neuro-fuzzy network model

Science.gov (United States)

Förner, K.; Polifke, W.

2017-10-01

The nonlinear acoustic behavior of Helmholtz resonators is characterized by a data-based reduced-order model, which is obtained by a combination of high-resolution CFD simulation and system identification. It is shown that even in the nonlinear regime, a linear model is capable of describing the reflection behavior at a particular amplitude with quantitative accuracy. This observation motivates to choose a local-linear model structure for this study, which consists of a network of parallel linear submodels. A so-called fuzzy-neuron layer distributes the input signal over the linear submodels, depending on the root mean square of the particle velocity at the resonator surface. The resulting model structure is referred to as an local-linear neuro-fuzzy network. System identification techniques are used to estimate the free parameters of this model from training data. The training data are generated by CFD simulations of the resonator, with persistent acoustic excitation over a wide range of frequencies and sound pressure levels. The estimated nonlinear, reduced-order models show good agreement with CFD and experimental data over a wide range of amplitudes for several test cases.

3. European conference of TRIGA users. Papers and abstracts

International Nuclear Information System (INIS)

1974-01-01

The Third European Conference of TRIGA Users was held October 29-31, 1974, in Neuherberg near Munich, Germany under the sponsorship of the Gesellschaft fur Strahlen and Umweltforschung mbH, Physikalischen-Technische Ableilung. The main topics were: experience in reactor operation, maintenance, measurements, fuel management and fuel performance, neutron physical experiments and other research programs

Global reconnection topology as inferred from plasma observations inside Kelvin-Helmholtz vortices

Directory of Open Access Journals (Sweden)

M. B. Bavassano Cattaneo

2010-04-01

Full Text Available During a long lasting period of northward interplanetary magnetic field and high solar wind speed (above 700 km/s, the Cluster spacecraft go across a number of very large rolled-up Kelvin-Helmholtz (KH vortices at the dusk magnetopause, close to the terminator. The peculiarity of the present event is a particular sequence of ions and electrons distribution functions observed repeatedly inside each vortex. In particular, whenever Cluster crosses the current layer inside the vortices, multiple field-aligned ion populations appear, suggesting the occurrence of reconnection. In addition, the ion data display a clear velocity filter effect both at the leading and at the trailing edge of each vortex. This effect is not present in the simultaneous electron data. Unlike other KH studies reported in the literature in which reconnection occurs within the vortices, in the present event the observations are not compatible with local reconnection, but are accounted for by lobe reconnection occurring along an extended X-line at the terminator in the Southern Hemisphere. The reconnected field lines "sink" across the magnetopause and then convect tailward-duskward where they become embedded in the vortices. Another observational evidence is the detected presence of solar wind plasma on the magnetospheric side of the vortices, which confirms unambiguously the occurrence of mass transport across the magnetopause already reported in the literature. The proposed reconnection scenario accounts for all the observational aspects, regarding both the transport process and the kinetic signatures.

Design and properties of silicon charged-particle detectors developed at the Institute of Electron Technology (ITE)

Science.gov (United States)

Wegrzecki, Maciej; Bar, Jan; Budzyński, Tadeusz; CieŻ, Michal; Grabiec, Piotr; Kozłowski, Roman; Kulawik, Jan; Panas, Andrzej; Sarnecki, Jerzy; Słysz, Wojciech; Szmigiel, Dariusz; Wegrzecka, Iwona; Wielunski, Marek; Witek, Krzysztof; Yakushev, Alexander; Zaborowski, Michał

2013-07-01

The paper discusses the design of charged-particle detectors commissioned and developed at the Institute of Electron Technology (ITE) in collaboration with foreign partners, used in international research on transactinide elements and to build personal radiation protection devices in Germany. Properties of these detectors and the results obtained using the devices are also presented. The design of the following epiplanar detector structures is discussed: ♢ 64-element chromatographic arrays for the COMPACT (Cryo On-line Multidetector for Physics And Chemistry of Transactinides) detection system used at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt (GSI) for research on Hassium, Copernicium and Flerovium, as well as elements 119 and 120, ♢ 2-element flow detectors for the COLD (Cryo On-Line Detector) system used for research on Copernicium and Flerovium at the Joint Institute for Nuclear Research, Dubna, ♢ detectors for a radon exposimeter and sensors for a neutron dosimeter developed at the Institut für Strahlenschutz, Helmholtz Zentrum München. The design of planar detectors - single-sided and double-sided strip detectors for the Focal Plane Detector Box used at GSI for research on Flerovium and elements 119 and 120 is also discussed.

Field calibration of a TLD albedo dosemeter in the high-energy neutron field of CERF

International Nuclear Information System (INIS)

Haninger, T.; Kleinau, P.; Haninger, S.

2017-01-01

The new albedo dosemeter-type AWST-TL-GD 04 has been calibrated in the CERF neutron field (CERN-EU high-energy Reference Field). This type of albedo dosemeter is based on thermoluminescent detectors (TLDs) and used by the individual monitoring service of the Helmholtz Zentrum Muenchen (AWST) since 2015 for monitoring persons, who are exposed occupationally against photon and neutron radiation. The motivation for this experiment was to gain a field specific neutron correction factor N n for workplaces at high-energy particle accelerators. N n is a dimensionless factor relative to a basic detector calibration with 137 Cs and is used to calculate the personal neutron dose in terms of H p (10) from the neutron albedo signal. The results show that the sensitivity of the albedo dosemeter for this specific neutron field is not significantly lower as for fast neutrons of a radionuclide source like 252 Cf. The neutron correction factor varies between 0.73 and 1.16 with a midrange value of 0.94. The albedo dosemeter is therefore appropriate to monitor persons, which are exposed at high-energy particle accelerators. (authors)

High-repetition-rate laser-proton acceleration from a condensed hydrogen jet

Energy Technology Data Exchange (ETDEWEB)

Obst, Lieselotte; Zeil, Karl; Metzkes, Josefine; Schlenvoigt, Hans-Peter; Rehwald, Martin; Sommer, Philipp; Brack, Florian; Schramm, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Goede, Sebastian; Gauthier, Maxence; Roedel, Christian; MacDonald, Michael; Schumaker, William; Glenzer, Siegfried [SLAC National Accelerator Laboratory, Stanford (United States)

2016-07-01

Applications of laser-accelerated protons demand a stable source of energetic particles at high repetition rates. We present the results of our experimental campaign in cooperation with MEC/SLAC at the 10Hz Ti:Sa laser Draco of Helmholtz-Zentrum Dresden-Rossendorf (HZDR), employing a pure condensed hydrogen jet as a renewable target. Draco delivers pulses of 30 fs and 5 J at 800 nm, focused to a 3 μm spot by an F/2.5 off-axis parabolic mirror. The jet's nominal electron density is approximately 30 times the critical density and its thickness is 2 μm, 5 μm or 10 μm, depending on the applied aperture on the source. Ion diagnostics reveal mono-species proton acceleration in a solid angle of at least +/-45 with respect to the incoming laser beam, with maximum energies of around 5 MeV. The expanding jet could be monitored on-shot with a temporally synchronized probe beam perpendicular to the pump laser axis. Recorded probe images resemble those of z-pinch experiments with metal wires and indicate an m=0 instability in the plasma.

Dimensional nanometrology with grazing incidence small angle X-ray scattering (GISAXS)

Energy Technology Data Exchange (ETDEWEB)

Wernecke, Jan; Krumrey, Michael; Cibik, Levent; Marggraf, Stefanie; Mueller, Peter [Physikalisch-Technische Bundesanstalt (PTB), Berlin (Germany)

2011-07-01

Reliable methods for dimensional characterisation of structures in the nanometer range are now a necessity in many fields of industry and science, e.g. for next-generation EUV lithography, new photovoltaic devices or magnetic nanoparticles. The method we have chosen for measurements of statistically averaged structural properties of nanostructured surfaces is GISAXS. This is a versatile technique to probe statistic properties such as mean particle size, spacial distribution and roughness of nanostructured surfaces and nanoparticle assemblies on top of or buried in bulk material. The GISAXS experiments were performed at the Four-Crystal Monochromator (FCM) beamline in the laboratory of PTB at BESSY II using the SAXS setup of the Helmholtz-Zentrum Berlin (HZB). This presentation will give a short overview of the instrumentation and the capabilities of the laboratory to perform dimensional nanometrology with GISAXS and will show first experimental results. Gratings for EUV lithography have been investigated in terms of coating layer thickness, roughness, grating period and blaze angle. Furthermore, dimensional properties of Au nanoparticles on silicon substrate were determined. The obtained particle sizes were in good agreement with SAXS measurements of these particles in liquid suspension.

Fabrication, Tuning, Treatment and Testing of Two 3.5 Cell Photo-Injector Cavities for the ELBE Linac

International Nuclear Information System (INIS)

Arnold, A.; Murcek, P.; Teichert, J.; Xiang, R.; Eremeev, G. V.; Kneisel, P.; Stirbet, M.; Turlington, L.

2011-01-01

As part of a CRADA (Cooperative Research and Development Agreement) between Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Thomas Jefferson Lab National Accelerator Facility (TJNAF) we have fabricated and tested two 1.3 GHz 3.5 cell photo-injector cavities from polycrystalline RRR niobium and large grain RRR niobium, respectively. The cavity with the better performance will replace the presently used injector cavity in the ELBE linac. The cavities have been fabricated and pre-tuned at TJNAF, while the more sophisticated final field tuning, the adjustment of the external couplings and the field profile measurement of transverse electric modes for RF focusing was done at HZDR. The following standard surface treatment and the vertical test was carried out at TJNAF's production facilities. A major challenge turned out to be the rinsing of the cathode cell, which has small opening (O-slash10mm) to receive the cathode stalk. Another unexpected problem encountered after etching, since large visible defects appeared in the least accessible cathode cell. This contribution reports about our experiences, initial results and the on-going diagnostic work to understand and fix the problems

Efficient models for photoionization produced by non-thermal gas discharges in air based on radiative transfer and the Helmholtz equations

International Nuclear Information System (INIS)

Bourdon, A; Pasko, V P; Liu, N Y; Celestin, S; Segur, P; Marode, E

2007-01-01

This paper presents formulation of computationally efficient models of photoionization produced by non-thermal gas discharges in air based on three-group Eddington and improved Eddington (SP 3 ) approximations to the radiative transfer equation, and on effective representation of the classic integral model for photoionization in air developed by Zheleznyak et al (1982) by a set of three Helmholtz differential equations. The reported formulations represent extensions of ideas advanced recently by Segur et al (2006) and Luque et al (2007), and allow fast and accurate solution of photoionization problems at different air pressures for the range 0.1 O 2 O 2 is the partial pressure of molecular oxygen in air in units of Torr ( p O 2 = 150 Torr) at atmospheric pressure) and R in cm is an effective geometrical size of the physical system of interest. The presented formulations can be extended to other gases and gas mixtures subject to availability of related emission, absorption and photoionization coefficients. The validity of the developed models is demonstrated by performing direct comparisons of the results from these models and results obtained from the classic integral model. Specific validation comparisons are presented for a set of artificial sources of photoionizing radiation with different Gaussian dimensions, and for a realistic problem involving development of a double-headed streamer at ground pressure. The reported results demonstrate the importance of accurate definition of the boundary conditions for the photoionization production rate for the solution of second order partial differential equations involved in the Eddington, SP 3 and the Helmholtz formulations. The specific algorithms derived from the classic photoionization model of Zheleznyak et al (1982), allowing accurate calculations of boundary conditions for differential equations involved in all three new models described in this paper, are presented. It is noted that the accurate formulation of

Large eddy simulation of turbulent and stably-stratified flows

International Nuclear Information System (INIS)

Fallon, Benoit

1994-01-01

The unsteady turbulent flow over a backward-facing step is studied by mean of Large Eddy Simulations with structure function sub grid model, both in isothermal and stably-stratified configurations. Without stratification, the flow develops highly-distorted Kelvin-Helmholtz billows, undergoing to helical pairing, with A-shaped vortices shed downstream. We show that forcing injected by recirculation fluctuations governs this oblique mode instabilities development. The statistical results show good agreements with the experimental measurements. For stably-stratified configurations, the flow remains more bi-dimensional. We show with increasing stratification, how the shear layer growth is frozen by inhibition of pairing process then of Kelvin-Helmholtz instabilities, and the development of gravity waves or stable density interfaces. Eddy structures of the flow present striking analogies with the stratified mixing layer. Additional computations show the development of secondary Kelvin-Helmholtz instabilities on the vorticity layers between two primary structures. This important mechanism based on baroclinic effects (horizontal density gradients) constitutes an additional part of the turbulent mixing process. Finally, the feasibility of Large Eddy Simulation is demonstrated for industrial flows, by studying a complex stratified cavity. Temperature fluctuations are compared to experimental measurements. We also develop three-dimensional un-stationary animations, in order to understand and visualize turbulent interactions. (author) [fr

Göttinger DigitalisierungsZentrum GDZ

CERN Document Server

In the beginning of 1997 the German Research Foundation (Deutsche Forschungsgemeinschaft) launched a new funding program for retrospective digitization of library materials as part of an initiative to build a German digital research library.

Global Simulations of the Asymmetry in Forming Kelvin-Helmholtz Instability at Mercury

Science.gov (United States)

Paral, J.; Rankin, R.

2013-12-01

MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) is the first spacecraft to provide data from the orbit of Mercury. After the probe's insertion into the orbit on March 2011, the in situ measurements revealed a dawn-dusk asymmetry in the observations of Kelvin-Helmholtz (KH) instability. This instability forms at the magnetopause boundary due to the high shear of the plasma flows. The asymmetry in the observations is unexpected and largely unexplained, although it has been speculated that finite ion gyroradius effect plays an important role. The large gyroradius implies that kinetic effects are important and thus must be taken into account. We employ global ion hybrid-kinetic simulations to obtain a 2D model of Mercury's magnetosphere. This code treats ions as particles and follows the full trajectory while electrons act as a charge neutralizing fluid. The planet is treated as the perfect conductor placed in the streaming solar wind to form a quasi steady state of the magnetosphere. By placing a virtual probe in the simulation domain we obtain time series of the plasma parameters which can be compared to the observations by the MESSENGER spacecraft. The comparison of the KH instability is remarkably close to the observations of MESSENGER; to within a factor of two. The model also confirms the asymmetry in the observations. The ion density obtained from the computer model is shown together with velocity vectors (represented by arrows). The solid line represents the trajectory of the third flyby of MESSENGER on September 29, 2009.

Computational issues and applications of line-elements to model subsurface flow governed by the modified Helmholtz equation

Science.gov (United States)

Bakker, Mark; Kuhlman, Kristopher L.

2011-09-01

Two new approaches are presented for the accurate computation of the potential due to line elements that satisfy the modified Helmholtz equation with complex parameters. The first approach is based on fundamental solutions in elliptical coordinates and results in products of Mathieu functions. The second approach is based on the integration of modified Bessel functions. Both approaches allow evaluation of the potential at any distance from the element. The computational approaches are applied to model transient flow with the Laplace transform analytic element method. The Laplace domain solution is computed using a combination of point elements and the presented line elements. The time domain solution is obtained through a numerical inversion. Two applications are presented to transient flow fields, which could not be modeled with the Laplace transform analytic element method prior to this work. The first application concerns transient single-aquifer flow to wells near impermeable walls modeled with line-doublets. The second application concerns transient two-aquifer flow to a well near a stream modeled with line-sinks.

Formulas for detecting a spherical stiff inclusion from interior data: a sensitivity analysis for the Helmholtz equation

International Nuclear Information System (INIS)

McLaughlin, Joyce; Oberai, Assad; Yoon, Jeong-Rock

2012-01-01

In this paper, we establish sensitivity results that are relevant for imaging stiffness in tissue but may also be useful in other contexts. The data are the displacement at a single frequency throughout the imaging domain. The goal is to determine how the quantities—(1) amplitude of displacement, or alternatively (2) the displacement itself, the average displacement, the phase or the phase gradient—change within a homogeneous stiff inclusion embedded within a homogeneous background. The results are easily interpreted formulas that show the dependence on the radius of the inclusion, the frequency and the stiffness contrast between the inclusion and the background. Our assumptions are: (1) the displacement satisfies the Helmholtz equation with the variable stiffness parameter; (2) the experiment produces a plane wave in the absence of any inclusions; (3) in 3D, the inclusion is spherical; (4) in 2D the inclusion is a circular disc; and alternatively in 3D the inclusion is an infinite circular cylinder. Our method of analysis is to use series expansions of the solution expanded about the center of the inclusion. (paper)

Hybrid simulations of plasma transport by Kelvin-Helmholtz instability at the magnetopause: magnetic shear

Energy Technology Data Exchange (ETDEWEB)

Cowee, Misa M [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Gary, S Peter [Los Alamos National Laboratory

2009-01-01

Two-dimensional hybrid (kinetic ions, massless fluid electrons) simulations of the Kelvin Helmholtz Instability (KHI) for a magnetopause configuration with a magnetic shear across the boundary are carried out to examine how the transport of magnetosheath plasma into the magnetosphere is affected by the shear field. Low magnetic shear conditions where the magnetosheath magnetic field is within 30{sup o} of northward is included in the simulations because KHI is thought to be important for plasma transport only for northward or near-northward interplanetary magnetic field orientations. The simulations show that coherent vortices can grow for these near-northward angles, and that they are sometimes more coherent than for pure northward conditions because the turbulence which breaks-down these vortices is reduced when there are magnetic tension forces. With increasing magnetic shear angle, the growth rate is reduced, and the vortices do not grow to as large of size which reduces the plasma transport. By tracking the individual particle motions diffusion coefficients can be obtained for the system, where the diffusion is not classical in nature but instead has a time dependence resulting from both the increasingly large-scale vortex motion and the small-scale turbulence generated in the break-down of the instabilities. Results indicate that diffusion on the order of 10{sup 9} m{sup 2}/s could possibly be generated by KHI on the flanks of the magnetosphere.

The Kelvin-Helmholtz instability in National Ignition Facility hohlraums as a source of gold-gas mixing

Energy Technology Data Exchange (ETDEWEB)

Vandenboomgaerde, M.; Bonnefille, M.; Gauthier, P. [CEA, DAM, DIF, F-91297 Arpajon (France)

2016-05-15

Highly resolved radiation-hydrodynamics FCI2 simulations have been performed to model laser experiments on the National Ignition Facility. In these experiments, cylindrical gas-filled hohlraums with gold walls are driven by a 20 ns laser pulse. For the first time, simulations show the appearance of Kelvin-Helmholtz (KH) vortices at the interface between the expanding wall material and the gas fill. In this paper, we determine the mechanisms which generate this instability: the increase of the gas pressure around the expanding gold plasma leads to the aggregation of an over-dense gold layer simultaneously with shear flows. At the surface of this layer, all the conditions are met for a KH instability to grow. Later on, as the interface decelerates, the Rayleigh-Taylor instability also comes into play. A potential scenario for the generation of a mixing zone at the gold-gas interface due to the KH instability is presented. Our estimates of the Reynolds number and the plasma diffusion width at the interface support the possibility of such a mix. The key role of the first nanosecond of the laser pulse in the instability occurrence is also underlined.

SIMULATIONS OF THE KELVIN–HELMHOLTZ INSTABILITY DRIVEN BY CORONAL MASS EJECTIONS IN THE TURBULENT CORONA

Energy Technology Data Exchange (ETDEWEB)

Gómez, Daniel O.; DeLuca, Edward E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Mininni, Pablo D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Física de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

2016-02-20

Recent high-resolution Atmospheric Imaging Assembly/Solar Dynamics Observatory images show evidence of the development of the Kelvin–Helmholtz (KH) instability, as coronal mass ejections (CMEs) expand in the ambient corona. A large-scale magnetic field mostly tangential to the interface is inferred, both on the CME and on the background sides. However, the magnetic field component along the shear flow is not strong enough to quench the instability. There is also observational evidence that the ambient corona is in a turbulent regime, and therefore the criteria for the development of the instability are a priori expected to differ from the laminar case. To study the evolution of the KH instability with a turbulent background, we perform three-dimensional simulations of the incompressible magnetohydrodynamic equations. The instability is driven by a velocity profile tangential to the CME–corona interface, which we simulate through a hyperbolic tangent profile. The turbulent background is generated by the application of a stationary stirring force. We compute the instability growth rate for different values of the turbulence intensity, and find that the role of turbulence is to attenuate the growth. The fact that KH instability is observed sets an upper limit on the correlation length of the coronal background turbulence.

Supresión de modos de vibración acústicos con un resonador Helmholtz

Directory of Open Access Journals (Sweden)

Guiguet Andrés

2003-01-01

Full Text Available La inserción de un Resonador Helmholtz (RH en las paredes laterales de un tubo, con ondas estacionarias en su interior, logra suprimir uno o más de sus modos resonantes si se elige adecuadamente la frecuencia del resonador. El RH puede actuar también como filtro de ondas propagantes.' En este caso, el RH atenua las ondas en un rango de frecuencia muy selectivo. En la mayoría de los textos de acústica, solamente se desarrolla la teoría que explica el filtrado de ondas propagantes. Sin embargo, en los laboratorios de física basica, donde se dispone solamente de tubos de Kundt de pequeña longitud, no es simple realizar un arreglo experimental que asegure la presencia de ondas propagantes puras en su interior. La falta de una teoría para ondas estacionarias y las dificultades experimentales que señalamos han producido algunas confusiones en trabajos que tratan sobre el tema. En este artículo se presenta un modelo teórico que describe satisfactoriamente el comportamiento del RH cuando funciona como filtro de ondas estacionarias y se marcan las diferencias con la situación en que opera como filtro de ondas propagantes.

Magnetoacoustic Waves and the Kelvin-Helmholtz Instability in a Steady Asymmetric Slab. I: The Effects of Varying Density Ratios

Science.gov (United States)

Barbulescu, M.; Erdélyi, R.

2018-06-01

Recent observations have shown that bulk flow motions in structured solar plasmas, most evidently in coronal mass ejections (CMEs), may lead to the formation of Kelvin-Helmholtz instabilities (KHIs). Analytical models are thus essential in understanding both how the flows affect the propagation of magnetohydrodynamic (MHD) waves, and what the critical flow speed is for the formation of the KHI. We investigate both these aspects in a novel way: in a steady magnetic slab embedded in an asymmetric environment. The exterior of the slab is defined as having different equilibrium values of the background density, pressure, and temperature on either side. A steady flow and constant magnetic field are present in the slab interior. Approximate solutions to the dispersion relation are obtained analytically and classified with respect to mode and speed. General solutions and the KHI thresholds are obtained numerically. It is shown that, generally, both the KHI critical value and the cut-off speeds for magnetoacoustic waves are lowered by the external asymmetry.

First Ph.D. Student Workshop of the Hermann von Helmholtz Association of National Research Centers (HGF) on ''Nuclear Safety Research''

International Nuclear Information System (INIS)

Knebel, J.U.; Sanchez Espinoza, V.H.

2006-03-01

The First Ph.D. Student Workshop ''Nuclear Safety Research'' of the Helmholtz Association of National Research Centers (HGF)'' was jointly organized by the Research Center Karlsruhe GmbH and the Energie Baden-Wuerttemberg AG (EnBW) from Wednesday 9th to Friday 11th March 2005. The workshop was opened with welcome greetings by Dr. Peter Fritz, Forschungszentrum Karlsruhe. Subsequently Dr. Joachim U. Knebel explained the main goals and the content of the workshop. The young scientists reported in 28 high-level presentations about their research work which covered a wide spectrum from reactor safety, partitions and transmutation, and innovative reactor systems, to safety research for nuclear waste disposal. The junior researchs showed excellent professional competence and demonstrated presentation qualities at the highest level. The successful funding of two Virtual Institutes, namely: the ''Competence in Nuclear Technologies'' and ''Functional Characteristics of Aquatic Interfaces both co-ordinated by Forschungszentrum Karlsruhe'', by the President of the Helmholtz Association Prof. Walter Kroell was the motivation for the organization of this first Ph.D. Student Workshop. Thanks to these two Virtual Institutes, the Reseach Center Karlsruhe and Juelich together with several univer-sities i.e. RWTH Aachen, Heidelberg, Karlsruhe, Muenster, and Stuttgart, have successfully financed eight Ph.D. and two post-doctoral students. Moreover, young scientists of the European Institute for Transuranium Elements (ITU) and additional seven Ph.D. Students, who are sponsored by the German nuclear industry (Framatome ANP, RWE Power, EnBW) in the frame of the Alliance Competence in on Nuclear Technology, and who are trained at Forschungszentrum Karlsruhe, actively contributed to this workshop. The EnBW-Award was handed over by Dr. Hans-Josef Zimmer, member of the board of directors of the EnBW-Kraftwerksgesellschaft, to Mrs. Ayelet Walter from the University of Stuttgart for the best

THE ROLE OF KELVIN–HELMHOLTZ INSTABILITY FOR PRODUCING LOOP-TOP HARD X-RAY SOURCES IN SOLAR FLARES

Energy Technology Data Exchange (ETDEWEB)

Fang, Xia; Yuan, Ding; Xia, Chun; Doorsselaere, Tom Van; Keppens, Rony [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium)

2016-12-10

We propose a model for the formation of loop-top hard X-ray (HXR) sources in solar flares through the inverse Compton mechanism, scattering the surrounding soft X-ray (SXR) photons to higher energy HXR photons. We simulate the consequences of a flare-driven energy deposit in the upper chromosphere in the impulsive phase of single loop flares. The consequent chromosphere evaporation flows from both footpoints reach speeds up to hundreds of kilometers per second, and we demonstrate how this triggers Kelvin–Helmholtz instability (KHI) in the loop top, under mildly asymmetric conditions, or more toward the loop flank for strongly asymmetric cases. The KHI vortices further fragment the magnetic topology into multiple magnetic islands and current sheets, and the hot plasma within leads to a bright loop-top SXR source region. We argue that the magnetohydrodynamic turbulence that appears at the loop apex could be an efficient accelerator of non-thermal particles, which the island structures can trap at the loop-top. These accelerated non-thermal particles can upscatter the surrounding thermal SXR photons emitted by the extremely hot evaporated plasma to HXR photons.

Simulation of leakage current measurement on medical devices using helmholtz coil configuration with different current flow

Science.gov (United States)

Sutanto, E.; Chandra, F.; Dinata, R.

2017-05-01

Leakage current measurement which can follow IEC standard for medical device is one of many challenges to be answered. The IEC 60601-1 has defined that the limit for a leakage current for Medical Device can be as low as 10 µA and as high as 500 µA, depending on which type of contact (applied part) connected to the patient. Most people are using ELCB (Earth-leakage circuit breaker) for safety purpose as this is the most common and available safety device in market. One type of ELCB devices is RCD (Residual Current Device) and this RCD type can measure the leakage current directly. This work will show the possibility on how Helmholtz Coil Configuration can be made to be like the RCD. The possibility is explored by comparing the magnetic field formula from each device, then it proceeds with a simulation using software EJS (Easy Java Simulation). The simulation will make sure the concept of magnetic field current cancellation follows the RCD concept. Finally, the possibility of increasing the measurement’s sensitivity is also analyzed. The sensitivity is needed to see the possibility on reaching the minimum leakage current limit defined by IEC, 0.01mA.

Simulation of leakage current measurement on medical devices using helmholtz coil configuration with different current flow

International Nuclear Information System (INIS)

Sutanto, E; Chandra, F; Dinata, R

2017-01-01

Leakage current measurement which can follow IEC standard for medical device is one of many challenges to be answered. The IEC 60601-1 has defined that the limit for a leakage current for Medical Device can be as low as 10 µA and as high as 500 µA, depending on which type of contact (applied part) connected to the patient. Most people are using ELCB (Earth-leakage circuit breaker) for safety purpose as this is the most common and available safety device in market. One type of ELCB devices is RCD (Residual Current Device) and this RCD type can measure the leakage current directly. This work will show the possibility on how Helmholtz Coil Configuration can be made to be like the RCD. The possibility is explored by comparing the magnetic field formula from each device, then it proceeds with a simulation using software EJS (Easy Java Simulation). The simulation will make sure the concept of magnetic field current cancellation follows the RCD concept. Finally, the possibility of increasing the measurement’s sensitivity is also analyzed. The sensitivity is needed to see the possibility on reaching the minimum leakage current limit defined by IEC, 0.01mA. (paper)

Image-Processing-Based Study of the Interfacial Behavior of the Countercurrent Gas-Liquid Two-Phase Flow in a Hot Leg of a PWR

Directory of Open Access Journals (Sweden)

Gustavo A. Montoya

2012-01-01

Full Text Available The interfacial behavior during countercurrent two-phase flow of air-water and steam-water in a model of a PWR hot leg was studied quantitatively using digital image processing of a subsequent recorded video images of the experimental series obtained from the TOPFLOW facility, Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR, Dresden, Germany. The developed image processing technique provides the transient data of water level inside the hot leg channel up to flooding condition. In this technique, the filters such as median and Gaussian were used to eliminate the drops and the bubbles from the interface and the wall of the test section. A Statistical treatment (average, standard deviation, and probability distribution function (PDF of the obtained water level data was carried out also to identify the flow behaviors. The obtained data are characterized by a high resolution in space and time, which makes them suitable for the development and validation of CFD-grade closure models, for example, for two-fluid model. This information is essential also for the development of mechanistic modeling on the relating phenomenon. It was clarified that the local water level at the crest of the hydraulic jump is strongly affected by the liquid properties.

E1 and M1 strength functions at low energy

Science.gov (United States)

Schwengner, Ronald; Massarczyk, Ralph; Bemmerer, Daniel; Beyer, Roland; Junghans, Arnd R.; Kögler, Toni; Rusev, Gencho; Tonchev, Anton P.; Tornow, Werner; Wagner, Andreas

2017-09-01

We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.

E1 and M1 strength functions at low energy

Directory of Open Access Journals (Sweden)

Schwengner Ronald

2017-01-01

Full Text Available We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.

Nanotomography endstation at the P05 beamline: Status and perspectives

Science.gov (United States)

Greving, I.; Ogurreck, M.; Marschall, F.; Last, A.; Wilde, F.; Dose, T.; Burmester, H.; Lottermoser, L.; Müller, M.; David, C.; Beckmann, F.

2017-06-01

The Imaging Beamline IBL/P05 at the DESY storage ring PETRA III, operated by the Helmholtz-Zentrum Geesthacht, has two dedicated endstations optimized for micro- and nanotomography experiments [1-3]. Here we present the status of the nanotomography endstation, highlight the latest instrumentation upgrades and present first experimental results. In particular in materials science, where structures with ceramics or metallic materials are of interest, X-ray energies of 15 keV and above are required even for sample sizes of several 10 μm in diameter. The P05 imaging beamline is dedicated to materials science and is designed to allow for imaging applications with X-ray energies of 10 to 50 keV. In addition to the full field X-ray microscopy setup, the layout of the nanotomography endstation allows switching to cone-beam configuration. Kinematics for X-ray optics like compound refractive lenses (CRLs), Fresnel zone plates (FZP) or beam-shaping optics are implemented and the installation of a Kirkpatrick Baez-mirror (KB mirror) system is foreseen at a later stage of the beamline development. Altogether this leads to a high flexibility of the nanotomography setup such that the instrument can be tailored to the specific experimental requirements of a range of sample systems.

Flying on hydrogen; Vliegen op waterstof

Energy Technology Data Exchange (ETDEWEB)

Van Wijngaarden, W. [Buero fuer Wissenschaft und Technologie, Botschaft des Koenigsreichs der Niederlaende, Berlin (Germany)

2008-11-15

The German Zentrum fuer Luft und Raumfahrt (German Aerospace Centre, DLR) wants to conduct a test flight with an airplane on fuel cells, the ANTARES DLR-H2. [mk]. [Dutch] Het Deutsches Zentrum fuer Luft und Raumfahrt (DLR) wil in 2008 een proefvlucht maken met een vliegtuig op brandstofcellen, de ANTARES DLR-H2.

Attorneys for the Ocean - Graduate Training in the Transatlantic Helmholtz Research School for Ocean System Science and Technology (HOSST/TOSST)

Science.gov (United States)

van den Bogaard, Christel; Dullo, Christian; Devey, Colin; Kienast, Markus; Wallace, Douglas

2016-04-01

The worldwide growth in population and standards of living is leading to ever increasing human pressure on the oceans: as a source of resources, a transportation/trade pathway, and a sink for pollutants. However, use of the world's ocean is not presently guided by any over-arching management plan at either national or international level. Marine science and technology provide the necessary foundation, both in terms of system understanding and observational and modeling tools, to address these issues and to ensure that management of ocean activities can be placed on the best-possible scientific footing. The transatlantic Helmholtz Research School Ocean Science and Technology pools the complementary expertise of the Helmholtz Centre for Ocean Research Kiel (GEOMAR), the Christian-Albrechts-Universität zu Kiel, Dalhousie University and the Institute for Ocean Research Enterprise (IORE), to train the next generation of researchers in the key scientific areas critical for responsible resource utilization and management of the ocean with special emphasis on our "local ocean" - the North Atlantic. The Research School is organized around three themes which encompass key sensitivities of the North Atlantic to external forcing and resource exploitation: 4D Ocean Dynamics, Ecosystem Hotspots, and Seafloor Structures. Interactions within and between these themes regulate how the ocean system responds to both anthropogenic and natural change. The HOSST/TOSST fellows gain an in-depth understanding of how these ocean systems interact, which in turn provides a solid understanding for the formulation of scientifically-sound management practices. Given the broad scope of the school, student education is two-pronged: it provides excellent institutional support where needed, including scientific input, personal support and financial incentives, while simultaneously generating an open "intellectual space" in which ingenious, often unpredictable, ideas can take root, overcoming

Four-Spacecraft Magnetic Curvature and Vorticity Analyses on Kelvin-Helmholtz Waves in MHD Simulations

Science.gov (United States)

Kieokaew, Rungployphan; Foullon, Claire; Lavraud, Benoit

2018-01-01

Four-spacecraft missions are probing the Earth's magnetospheric environment with high potential for revealing spatial and temporal scales of a variety of in situ phenomena. The techniques allowed by these four spacecraft include the calculation of vorticity and the magnetic curvature analysis (MCA), both of which have been used in the study of various plasma structures. Motivated by curved magnetic field and vortical structures induced by Kelvin- Helmholtz (KH) waves, we investigate the robustness of the MCA and vorticity techniques when increasing (regular) tetrahedron sizes, to interpret real data. Here for the first time, we test both techniques on a 2.5-D MHD simulation of KH waves at the magnetopause. We investigate, in particular, the curvature and flow vorticity across KH vortices and produce time series for static spacecraft in the boundary layers. The combined results of magnetic curvature and vorticity further help us to understand the development of KH waves. In particular, first, in the trailing edge, the magnetic curvature across the magnetopause points in opposite directions, in the wave propagation direction on the magnetosheath side and against it on the magnetospheric side. Second, the existence of a "turnover layer" in the magnetospheric side, defined by negative vorticity for the duskside magnetopause, which persists in the saturation phase, is reminiscent of roll-up history. We found significant variations in the MCA measures depending on the size of the tetrahedron. This study lends support for cross-scale observations to better understand the nature of curvature and its role in plasma phenomena.

Pickup Ion Dynamics in the Outer Heliosheath Associated with the Growth of Kelvin-Helmholtz Instability at the Heliopause

Science.gov (United States)

Tsubouchi, K.

2017-12-01

A discovery of "IBEX ribbon", localized bright emission of energetic neutral atoms, has brought new insights into the plasma environment of its source region beyond the heliosphere. It has been basically established that its geometrical property is associated with the local interstellar magnetic field draped on the heliopause, and pickup ions (PUIs) in the outer heliosheath (OHS) must be its primary source particles. Understanding the PUI dynamics in OHS more in detail is our motivation for this study. We performed two-dimensional hybrid simulations to evaluate the response of PUIs to the structural variation in the heliosheath. We assumed the simulation system such that the background plasma is hot solar wind in the inner heliosheath and cold interstellar plasma in OHS, and the directions of these flows are tangential to the heliopause. Such a situation leads to the growth of Kelvin-Helmholtz instability (KHI), where the plasma mixing and turbulence excitation takes place. We identified that non-stationarity and non-uniformity emerges in the PUI density structure in a specific energy range as KHI process advances. Relevance of these results to the expected observation like IBEX ribbon will be discussed.

Investigation of exhaust gases at blends of fuels/biofuels at the Helmholtz Virtual Institute for Complex Molecular Systems in Environmental Health; Abgasuntersuchungen an Kraftstoffen/Biokraftstoff-Blends im Rahmen des Helmholtz Virtual Institute for Complex Molecular Systems in Environmental Health

Energy Technology Data Exchange (ETDEWEB)

Streibel, Thorsten [Rostock Univ. (Germany). Inst. fuer Chemie, Analytische Chemie; Adam, Thomas; Grabowsky, Jana; Sklorz, Martin; Zimmermann, Ralf

2012-07-01

The objective of the ''Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health'' (HICE) is the establishment of a long-term scientific research initiative for the investigation of the causes and mechanisms of environmentally influenced diseases. In the initial phase (INF funding period) the HICE focuses on a deeper understanding of the impact of anthropogenic aerosols on human health. Based on current hypotheses, reactive organic compounds in particle as well as in gas phase of aerosols are particularly relevant. Innovative in-vitro human lung tissue models and selected susceptible animal models are exposed to aerosols, and separated gas and particle phases from relevant sources. The response of the biological systems is investigated by state-of-the-art analytical techniques on different biological levels (transcriptome, proteome, metabolome, toxicological parameters). The second central topic is the real-time characterization of emissions (gas- and particulate phase) from internal combustion engines with a special focus on the influence of the biodiesel content. For this, mass spectrometry with photo ionization will be applied for the detection of organic compounds. Preliminary studies dealt with the online investigation of the gas phase of truck diesel exhaust as well as the offline particulate phase characterization after thermal desorption. Both studies detected primarily (poly)aromatic hydrocarbons. (orig.)

The new 6 MV AMS-facility DREAMS at Dresden

International Nuclear Information System (INIS)

Akhmadaliev, Shavkat; Heller, René; Hanf, Daniel; Rugel, Georg; Merchel, Silke

2013-01-01

Highlights: ► New 6 MV tandem accelerator in operation in Germany for AMS, IBA and HE-implantation. ► DREsden AMS (DREAMS) primarily used for radionuclides 10 Be, 26 Al, 36 Cl, 41 Ca and 129 I. ► Quality assurance by traceable calibration materials and interlaboratory comparisons. High accuracy data for future DREAMS users. ► Energy calibration of accelerator by 1 H( 15 N,γα) 12 C yield correction factor of 1.019. - Abstract: A new 6 MV electrostatic tandem accelerator has been put into operation at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The system is equipped for accelerator mass spectrometry and opens a new research field at HZDR and the Helmholtz Association. It will be also used for ion beam analysis as well as for material modification via high-energy ion implantation. The research activity at the DREsden Accelerator Mass Spectrometry facility (DREAMS) based on a 6 MV Tandetron is primarily dedicated to the long-lived radioisotopes of 10 Be, 26 Al, 36 Cl, 41 Ca, and 129 I. DREAMS background levels have been found to be at 4.5 × 10 −16 for 10 Be/ 9 Be, 8 × 10 −16 for 26 Al/ 27 Al, 3 × 10 −15 for 36 Cl/ 35 Cl and 8 × 10 −15 for 41 Ca/ 40 Ca, respectively. The observed background of 2 × 10 −13 for 129 I/ 127 I originates from intrinsic 129 I from AgI produced from commercial KI. The introduction of quality assurance approaches for AMS, such as the use of traceable calibration materials and taking part in interlaboratory comparisons, guarantees high accuracy data for future DREAMS users. During first experiments an energy calibration of the accelerator has been carried out using the nuclear reaction 1 H( 15 N,γα) 12 C yielding an energy correction factor of 1.019.

Tri-axial square Helmholtz coil system at the Alibag Magnetic Observatory: upgraded to a magnetic sensor calibration facility

Science.gov (United States)

Mahavarkar, Prasanna; John, Jacob; Dhapre, Vijay; Dongre, Varun; Labde, Sachin

2018-04-01

A tri-axial square Helmholtz coil system for the study of palaeomagnetic studies, manufactured by GEOFYZIKA (former Czechoslovakia), was successfully commissioned at the Alibag Magnetic Observatory (IAGA code: ABG) in the year 1985. This system was used for a few years, after which the system encountered technical problems with the control unit. Rectification of the unit could not be undertaken, as the information document related to this system was not available, and as a result the system had been lying in an unused state for a long time, until 2015, when the system was recommissioned and upgraded to a test facility for calibrating the magnetometer sensors. We have upgraded the system with a constant current source and a data-logging unit. Both of these units have been designed and developed in the institute laboratory. Also, re-measurements of the existing system have been made thoroughly. The upgraded system is semi-automatic, enabling non-specialists to operate it after a brief period of instruction. This facility is now widely used at the parent institute and external institutions to calibrate magnetometers and it also serves as a national facility. Here the design of this system with the calibration results for the space-borne fluxgate magnetometers is presented.

Tri-axial square Helmholtz coil system at the Alibag Magnetic Observatory: upgraded to a magnetic sensor calibration facility

Directory of Open Access Journals (Sweden)

P. Mahavarkar

2018-04-01

Full Text Available A tri-axial square Helmholtz coil system for the study of palaeomagnetic studies, manufactured by GEOFYZIKA (former Czechoslovakia, was successfully commissioned at the Alibag Magnetic Observatory (IAGA code: ABG in the year 1985. This system was used for a few years, after which the system encountered technical problems with the control unit. Rectification of the unit could not be undertaken, as the information document related to this system was not available, and as a result the system had been lying in an unused state for a long time, until 2015, when the system was recommissioned and upgraded to a test facility for calibrating the magnetometer sensors. We have upgraded the system with a constant current source and a data-logging unit. Both of these units have been designed and developed in the institute laboratory. Also, re-measurements of the existing system have been made thoroughly. The upgraded system is semi-automatic, enabling non-specialists to operate it after a brief period of instruction. This facility is now widely used at the parent institute and external institutions to calibrate magnetometers and it also serves as a national facility. Here the design of this system with the calibration results for the space-borne fluxgate magnetometers is presented.

Solution of the Helmholtz-Poincare Wave Equation using the coupled boundary integral equations and optimal surface eigenfunctions

International Nuclear Information System (INIS)

Werby, M.F.; Broadhead, M.K.; Strayer, M.R.; Bottcher, C.

1992-01-01

The Helmholtz-Poincarf Wave Equation (H-PWE) arises in many areas of classical wave scattering theory. In particular it can be found for the cases of acoustical scattering from submerged bounded objects and electromagnetic scattering from objects. The extended boundary integral equations (EBIE) method is derived from considering both the exterior and interior solutions of the H-PWECs. This coupled set of expressions has the advantage of not only offering a prescription for obtaining a solution for the exterior scattering problem, but it also obviates the problem of irregular values corresponding to fictitious interior eigenvalues. Once the coupled equations are derived, they can be obtained in matrix form by expanding all relevant terms in partial wave expansions, including a bi-orthogonal expansion of the Green's function. However some freedom in the choice of the surface expansion is available since the unknown surface quantities may be expanded in a variety of ways so long as closure is obtained. Out of many possible choices, we develop an optimal method to obtain such expansions which is based on the optimum eigenfunctions related to the surface of the object. In effect, we convert part of the problem (that associated with the Fredholms integral equation of the first kind) an eigenvalue problem of a related Hermitian operator. The methodology will be explained in detail and examples will be presented

Earthquake Swarm in Armutlu Peninsula, Eastern Marmara Region, Turkey

Science.gov (United States)

Yavuz, Evrim; Çaka, Deniz; Tunç, Berna; Serkan Irmak, T.; Woith, Heiko; Cesca, Simone; Lühr, Birger-Gottfried; Barış, Şerif

2015-04-01

The most active fault system of Turkey is North Anatolian Fault Zone and caused two large earthquakes in 1999. These two earthquakes affected the eastern Marmara region destructively. Unbroken part of the North Anatolian Fault Zone crosses north of Armutlu Peninsula on east-west direction. This branch has been also located quite close to Istanbul known as a megacity with its high population, economic and social aspects. A new cluster of microseismic activity occurred in the direct vicinity southeastern of the Yalova Termal area. Activity started on August 2, 2014 with a series of micro events, and then on August 3, 2014 a local magnitude is 4.1 event occurred, more than 1000 in the followed until August 31, 2014. Thus we call this tentatively a swarm-like activity. Therefore, investigation of the micro-earthquake activity of the Armutlu Peninsula has become important to understand the relationship between the occurrence of micro-earthquakes and the tectonic structure of the region. For these reasons, Armutlu Network (ARNET), installed end of 2005 and equipped with currently 27 active seismic stations operating by Kocaeli University Earth and Space Sciences Research Center (ESSRC) and Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ), is a very dense network tool able to record even micro-earthquakes in this region. In the 30 days period of August 02 to 31, 2014 Kandilli Observatory and Earthquake Research Institute (KOERI) announced 120 local earthquakes ranging magnitudes between 0.7 and 4.1, but ARNET provided more than 1000 earthquakes for analyzes at the same time period. In this study, earthquakes of the swarm area and vicinity regions determined by ARNET were investigated. The focal mechanism of the August 03, 2014 22:22:42 (GMT) earthquake with local magnitude (Ml) 4.0 is obtained by the moment tensor solution. According to the solution, it discriminates a normal faulting with dextral component. The obtained focal mechanism solution is

Study on partitioning and transmutation (P and T) of high-level waste. Status of R and D. Final report; Studie zur Partitionierung und Transmutation (P and T) hochradioaktiver Abfaelle. Stand der Grundlagen- und technologischen Forschung. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Merk, Bruno; Glivici-Cotruta, Varvara

2014-07-01

The main project, where this sub project contributed to, has been structured into two modules: module A (funded by the federal ministry of economics, managed by KIT) and module B (funded by the federal ministry of education and research, managed by acatech). Partners in module A were DBE TECHNOLOGY GmbH, the Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Karlsruher Institute of Technology (KIT) and the Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen, in co-operation with the Forschungszentrum Juelich (FZJ). Modul B has been executed by the Zentrum fuer Interdisziplinaere Risiko- und Innovationsforschung der Universitaet Stuttgart (ZIRIUS). The overall coordination has been carried out by the Deutsche Akademie der Technikwissenschaften (acatech). The social implications have been evaluated in module B based on the analysis of the scientific and technological aspects in module A. Recommendations for communication and actions to be taken for the future positioning of P and T have been developed. In the project part, coordinated by HZDR - status of R and D - an overview on the whole topic P and T is given. The topic is opened by a short description of reactor systems possible for transmutation. In the following the R and D status of separation technologies, safety technology, accelerator technology, liquid metal technology, spallation target development, transmutation fuel and structural material development, as well as waste conditioning is described. The topic is completed by the specifics of transmutation systems, the basic physics and core designs, the reactor physics, the simulation tools and the development of Safety Approaches. Additionally, the status of existing irradiation facilities with fast neutron spectrum is described. Based on the current R and D status, the research and technology gaps in the topics: separation and conditioning, accelerator and spallation target, and reactor

Study on partitioning and transmutation (P and T) of high-level waste. Status of R and D. Final report

International Nuclear Information System (INIS)

Merk, Bruno; Glivici-Cotruta, Varvara

2014-01-01

The main project, where this sub project contributed to, has been structured into two modules: module A (funded by the federal ministry of economics, managed by KIT) and module B (funded by the federal ministry of education and research, managed by acatech). Partners in module A were DBE TECHNOLOGY GmbH, the Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Karlsruher Institute of Technology (KIT) and the Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen, in co-operation with the Forschungszentrum Juelich (FZJ). Modul B has been executed by the Zentrum fuer Interdisziplinaere Risiko- und Innovationsforschung der Universitaet Stuttgart (ZIRIUS). The overall coordination has been carried out by the Deutsche Akademie der Technikwissenschaften (acatech). The social implications have been evaluated in module B based on the analysis of the scientific and technological aspects in module A. Recommendations for communication and actions to be taken for the future positioning of P and T have been developed. In the project part, coordinated by HZDR - status of R and D - an overview on the whole topic P and T is given. The topic is opened by a short description of reactor systems possible for transmutation. In the following the R and D status of separation technologies, safety technology, accelerator technology, liquid metal technology, spallation target development, transmutation fuel and structural material development, as well as waste conditioning is described. The topic is completed by the specifics of transmutation systems, the basic physics and core designs, the reactor physics, the simulation tools and the development of Safety Approaches. Additionally, the status of existing irradiation facilities with fast neutron spectrum is described. Based on the current R and D status, the research and technology gaps in the topics: separation and conditioning, accelerator and spallation target, and reactor

Using the minimum principle for the Helmholtz free energy in the analysis of the equilibria of a van der Waals fluid

International Nuclear Information System (INIS)

Ascoli, Sergio; Malvestuto, Vincenzo

2004-01-01

For a fluid system, obeying a state equation of the van der Waals type, the gas and the liquid phases can coexist in equilibrium, at a given temperature, only if the volume of the system is kept fixed. Thus, in order to study the two-phase equilibria of a fluid system, it seemed quite natural to choose the molar volume as the independent variable, and, consequently, the Helmholtz free energy as the proper thermodynamic potential for the application of the minimum principle. Specific computations are here carried out for a single van der Waals fluid, namely, pure water at 300 0 C. As a result, the present treatment indicates a simple and effective way to identify the whole range of molar volumes where the equilibrium preferred by the system is a two-phase equilibrium. This range results to be wider than the interval of strict instability of the van der Waals isotherm. Finally, it is pointed out that all the results, obtained here for the van der Waals state equation, can be extended to all the state equations of the same type

The test beamline of the European Spallation Source – Instrumentation development and wavelength frame multiplication

International Nuclear Information System (INIS)

Woracek, R.; Hofmann, T.; Bulat, M.; Sales, M.; Habicht, K.; Andersen, K.; Strobl, M.

2016-01-01

The European Spallation Source (ESS), scheduled to start operation in 2020, is aiming to deliver the most intense neutron beams for experimental research of any facility worldwide. Its long pulse time structure implies significant differences for instrumentation compared to other spallation sources which, in contrast, are all providing short neutron pulses. In order to enable the development of methods and technology adapted to this novel type of source well in advance of the first instruments being constructed at ESS, a test beamline (TBL) was designed and built at the BER II research reactor at Helmholtz-Zentrum Berlin (HZB). Operating the TBL shall provide valuable experience in order to allow for a smooth start of operations at ESS. The beamline is capable of mimicking the ESS pulse structure by a double chopper system and provides variable wavelength resolution as low as 0.5% over a wide wavelength band between 1.6 Å and 10 Å by a dedicated wavelength frame multiplication (WFM) chopper system. WFM is proposed for several ESS instruments to allow for flexible time-of-flight resolution. Hence, ESS will benefit from the TBL which offers unique possibilities for testing methods and components. This article describes the main capabilities of the instrument, its performance as experimentally verified during the commissioning, and its relevance to currently starting ESS instrumentation projects.

The plain truth about forming a plane wave of neutrons

Energy Technology Data Exchange (ETDEWEB)

Wagh, Apoorva G., E-mail: nintsspd@barc.gov.i [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Abbas, Sohrab [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Treimer, Wolfgang [Helmholtz Zentrum Berlin, Glienicker Str. 100, D-14109 Berlin (Germany)

2011-04-01

We have attained the first sub-arcsecond collimation of a monochromatic neutron beam by diffracting neutrons from a Bragg prism, viz. a single crystal prism operating in the vicinity of Bragg incidence. Analytical as well numerical computations based on the dynamical diffraction theory, led to the optimised collimator configuration of a silicon {l_brace}1 1 1{r_brace} Bragg prism for 5.26 A neutrons. We fabricated a Bragg prism to these specifications, tested and operated it at the double diffractometer setup in Helmholtz Zentrum Berlin to produce a 0.58 arcsec wide monochromatic neutron beam. With a similarly optimised Bragg prism analyser of opposite asymmetry, we recorded a 0.62 arcsec wide virgin rocking curve for this ultra-parallel beam. With this nearly plane-wave neutron beam, we have recorded the first ever USANS spectrum in Q{approx}10{sup -6} A{sup -1} range with a hydroxyapatite casein protein sample and demonstrated the instrument capability to characterise agglomerates up to 150 {mu}m in size. The super-collimated monochromatic beam has also enabled us to record the first neutron diffraction pattern from a macroscopic grating of 200 {mu}m period. The transverse coherence length of 175 {mu}m (FWHM) of the ultra-parallel beam derived from the analysis of this pattern, is the greatest achieved to date for A wavelength neutrons.

Monte Carlo simulation of semiconductor detector response to "2"2"2Rn and "2"2"0Rn environments

International Nuclear Information System (INIS)

Irlinger, J.; Trinkl, S.; Wielunksi, M.; Tschiersch, J.; Rühm, W.

2016-01-01

A new electronic radon/thoron monitor employing semiconductor detectors based on a passive diffusion chamber design has been recently developed at the Helmholtz Zentrum München (HMGU). This device allows for acquisition of alpha particle energy spectra, in order to distinguish alpha particles originating from radon and radon progeny decays, as well as those originating from thoron and its progeny decays. A Monte-Carlo application is described which uses the Geant4 toolkit to simulate these alpha particle spectra. Reasonable agreement between measured and simulated spectra were obtained for both "2"2"0Rn and "2"2"2Rn, in the energy range between 1 and 10 MeV. Measured calibration factors could be reproduced by the simulation, given the uncertainties involved in the measurement and simulation. The simulated alpha particle spectra can now be used to interpret spectra measured in mixed radon/thoron atmospheres. The results agreed well with measurements performed in both radon and thoron gas environments. It is concluded that the developed simulation allows for an accurate prediction of calibration factors and alpha particle energy spectra. - Highlights: • A method was developed to simulate alpha particle spectra from radon/thoron decay. • New monitor features alpha-particle-spectroscopy based on silicon detectors. • A method is presented to quantify radon/thoron concentrations in mixed atmospheres. • The calibration factor can be simulated for various environmental parameters.

Calculation of coupled bunch effects in the synchrotron light source BESSY VSR

Energy Technology Data Exchange (ETDEWEB)

Ruprecht, Martin

2016-02-22

In the scope of this thesis, the strength of coupled bunch instabilities (CBIs) driven by longitudinal monopole higher order modes (HOMs) and transverse dipole and quadrupole HOMs is evaluated for the upgrade project BESSY Variable Pulse Length Storage Ring (BESSY VSR) at Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH (HZB), based on analytic calculations and tracking simulations, and compared to the performance of an active bunch-by-bunch feedback (BBFB). Algorithms for tracking codes are derived, and a semi-empirical formula for the estimation of transverse quadrupole CBIs is presented. CBI studies are an integral part of the benchmarking of the cavity models for BESSY VSR and have been accompanying and influencing their entire design process. Based on the BESSY VSR cavity model with highly advanced HOM damping, beam stability is likely to be reached with a BBFB system, independent of the bunch fill pattern. Additionally, measurements of CBIs have been performed at BESSY II and the Metrology Light Source of the Physikalisch-Technische Bundesanstalt (MLS), where the longitudinal long range impedance was characterized. Transient beam loading is evaluated by means of analytic formulas and new experimentally verified tracking codes. For the baseline bunch fill pattern of BESSY VSR, it is shown that the particular setup of cavity frequencies amplifies the transient effect on the long bunch, limiting its elongation and potentially resulting in increased Touschek losses.

Numerical simulations of counter-current two-phase flow experiments in a PWR hot leg model using an interfacial area density model

Energy Technology Data Exchange (ETDEWEB)

Hoehne, Thomas, E-mail: t.hoehne@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Deendarlianto,; Lucas, Dirk [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany)

2011-10-15

In order to improve the understanding of counter-current two-phase flows and to validate new physical models, CFD simulations of 1/3rd scale model of the hot leg of a German Konvoi PWR with rectangular cross section was performed. Selected counter-current flow limitation (CCFL) experiments at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) were calculated with ANSYS CFX 12.1 using the multi-fluid Euler-Euler modeling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a k-{omega} turbulence model for each phase. In the simulation, the surface drag was approached by a new correlation inside the Algebraic Interfacial Area Density (AIAD) model. The AIAD model allows the detection of the morphological form of the two phase flow and the corresponding switching via a blending function of each correlation from one object pair to another. As a result this model can distinguish between bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicated that quantitative agreement of the CCFL characteristics between calculation and experimental data was obtained. The goal is to provide an easy usable AIAD framework for all Code users, with the possibility of the implementation of their own correlations.

Numerical simulations of counter-current two-phase flow experiments in a PWR hot leg model using an interfacial area density model

Energy Technology Data Exchange (ETDEWEB)

Hohne, T.; Deendarlianto; Vallee, C.; Lucas, D.; Beyer, M., E-mail: t.hoehne@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Inst. of Safety Research, Dresden (Germany)

2011-07-01

In order to improve the understanding of counter-current two-phase flows and to validate new physical models, CFD simulations of 1/3rd scale model of the hot leg of a German Konvoi PWR with rectangular cross section was performed. Selected counter-current flow limitation (CCFL) experiments at the Helmholtz-Zentrum Dresden- Rossendorf (HZDR) were calculated with ANSYS CFX 12.1 using the multi-fluid Euler-Euler modeling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a SST turbulence model for each phase. In the simulation, the surface drag was approached by a new correlation inside the Algebraic Interfacial Area Density (AIAD) model. The AIAD model allows the detection of the morphological form of the two phase flow and the corresponding switching via a blending function of each correlation from one object pair to another. As a result this model can distinguish between bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicated that quantitative agreement of the CCFL characteristics between calculation and experimental data was obtained. The goal is to provide an easy usable AIAD framework for all ANSYS CFX users, with the possibility of the implementation of their own correlations. (author)

The test beamline of the European Spallation Source – Instrumentation development and wavelength frame multiplication

Energy Technology Data Exchange (ETDEWEB)

Woracek, R., E-mail: robin.woracek@esss.se [European Spallation Source ESS ERIC, P.O. Box 176, SE-22100 Lund (Sweden); Hofmann, T.; Bulat, M. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Sales, M. [Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby (Denmark); Habicht, K. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin (Germany); Andersen, K. [European Spallation Source ESS ERIC, P.O. Box 176, SE-22100 Lund (Sweden); Strobl, M. [European Spallation Source ESS ERIC, P.O. Box 176, SE-22100 Lund (Sweden); Technical University of Denmark, Fysikvej, 2800 Kgs. Lyngby (Denmark)

2016-12-11

The European Spallation Source (ESS), scheduled to start operation in 2020, is aiming to deliver the most intense neutron beams for experimental research of any facility worldwide. Its long pulse time structure implies significant differences for instrumentation compared to other spallation sources which, in contrast, are all providing short neutron pulses. In order to enable the development of methods and technology adapted to this novel type of source well in advance of the first instruments being constructed at ESS, a test beamline (TBL) was designed and built at the BER II research reactor at Helmholtz-Zentrum Berlin (HZB). Operating the TBL shall provide valuable experience in order to allow for a smooth start of operations at ESS. The beamline is capable of mimicking the ESS pulse structure by a double chopper system and provides variable wavelength resolution as low as 0.5% over a wide wavelength band between 1.6 Å and 10 Å by a dedicated wavelength frame multiplication (WFM) chopper system. WFM is proposed for several ESS instruments to allow for flexible time-of-flight resolution. Hence, ESS will benefit from the TBL which offers unique possibilities for testing methods and components. This article describes the main capabilities of the instrument, its performance as experimentally verified during the commissioning, and its relevance to currently starting ESS instrumentation projects.

Investigation of Kelvin-Helmholtz Instability in the boundary layer using Doppler lidar and radiosonde data

Science.gov (United States)

Das, Subrata Kumar; Das, Siddarth Shankar; Saha, Korak; Murali Krishna, U. V.; Dani, K. K.

2018-04-01

Characteristics of Kelvin Helmholtz Instability (KHI) using Doppler wind lidar observation have rarely been reported during the Indian summer monsoon season. In this paper, we present a case study of KHI near planetary boundary layer using Doppler wind lidar and radiosonde measurements at Mahabubnagar, a tropical Indian station. The data was collected during the Integrated Ground Observation Campaign (June-October 2011) under the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment-2011. The continuous wind lidar observation during 10-16 August 2011 shows there is an increase in carrier-to-noise ratio values near planetary boundary layer from 03:00 to 11:00 LT on 13 August; reveals the formation of KHI. There is a strong power bursts pattern corresponding to high turbulence characteristics in the early half of the day. The KHI temporal evolution from initial to dissipating stage is observed with clear variation in the carrier-to-noise ratio values. The observed KHI billows are in the height between 600 and 1200 m and lasted for about 7.5 h. The vertical velocity from Doppler lidar measurement shows the presence of updrafts after breaking of KHI in the boundary layer. The presence of strong wind shear, high stability parameter, low Richardson number and high relative humidity during the enhanced carrier-to-noise ratio period indicates the ideal condition for the formation and persistence of this dynamic instability. A typical characteristic of trapped humidity above the KHI billows suggest the presence of strong inversion. A wavelet analysis of 3-dimensional wind components show dominant periodicity of 45-65 min and the periodicity in vertical wind is more prominent.

On coupled development of MHD instabilities of Rayleigh-Taylor and Kelvin-Helmholtz types in nonuniform gas-plasmas flows

International Nuclear Information System (INIS)

Likhachev, A P; Medin, S A

2010-01-01

The simultaneous development of the MHD instabilities of Raylegh-Taylor and Kelvin-Helmholtz types at the interface between high-conducting plasmoid and surrounding non- or low-conducting gas is considered. The linear stage of the RTI development is studied analytically for incompressible and compressible fluids. The nonlinear stage of the individual development of the RTI and the coupled development of both instabilities has been investigated numerically. The time-dependent two-dimensional numerical model based on the solution of the Euler gasdynamic equations with body momentum and energy sources of MHD origin has been developed and used in calculations. A disturbance introducing in the background flow has been periodic with varied assignment type and wave length. Fundamental difference between the results of linear and nonlinear analysis has been revealed. In particular, the increment of the RTI development at nonlinear stage is one-two order of magnitude less than that predicted by linear theory and rather weakly depends on initial disturbance mode. In linear analysis the coupled development of the RTI and the KHI is determined by simple summing of the two effects in the expression of wave increment, whereas in nonlinear case the mutual influence of the instabilities leads to essential alterations in their development, main of which is the intensive 'layer-by-layer' destruction of the plasmoid surface.

Fast Reactor Knowledge Organization System (FR-KOS)

International Nuclear Information System (INIS)

Costantini, Livio

2013-01-01

FR-KOS Web-portal general concepts: FR-KOS web-portal is an integrated and unique solution for knowledge preservation, retrieval and management in fast reactor (FR) knowledge domain; The exploitation of the FR-KOS provides an effective and flexible tool to access FR knowledge repositories. The dynamic and interactive process of searching information is guided by structures that are based on the FR Taxonomy; FR-KOS can be extended to other types of reactor and technologies, such as PWR, WWER, BWR, CANDU, etc. In addition can also be utilized in other information management process such as the preservation of nuclear accidents knowledg;. FR-KOS addresses needs in non-structured knowledge preservation for both embarking countries and countries with established nuclear power; FR-KOS repositories contain more that 50.000 samples of technical and scientific publications, including full text documents in different languages (English, German, French and eventually in Russian)

Absorption of selected radionuclides. Analysis of a literature study. Resorption ausgewaehlter Radionuklide. Analyse einer Literaturstudie

Energy Technology Data Exchange (ETDEWEB)

Roedler, H D; Kraus, H M

1979-12-01

In October 1978, the Institut fuer Energie- und Umweltforschung Heidelberg e.V. published a contribution to part 26 of the model study of radio-ecology at Biblis under the title 'Estimation of the absorption of radionuclides from the gastrointestinal tract in the blood'. Using the example of this contribution, a critical analysis is made to show how a selection of the information contained in various scientific publications and other items of literature can give uncritical readers the impression that all statements made are scientifically well founded.

75 FR 5320 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2010-02-02

..., identified by FR 4004, FR MSD-4, FR MSD-5, FR G-FIN, or FR G-FINW, by any of the following methods: Agency... form number: FR MSD-4 and FR MSD-5. OMB control number: 7100-0100 and 7100-0101. Frequency: On occasion... dealers. Estimated annual reporting hours: FR MSD-4, 48 hours; and FR MSD-5, 36 hours. Estimated average...

Comparative design study of FR plants with various coolants. 1. Studies on Na coolant FR, Pb-Bi coolant FR, gas coolant FR

International Nuclear Information System (INIS)

Konomura, Mamoru; Shimakawa, Yoshio; Hori, Toru; Kawasaki, Nobuchika; Enuma, Yasuhiro; Kida, Masanori; Kasai, Shigeo; Ichimiya, Masakazu

2001-01-01

In Phase I of the Feasibility Studies on the Commercialized Fast Reactor (FR) Cycle System, plant designs on FR were performed with various coolants. This report describes the plant designs on FR with sodium, lead-bismuth, CO 2 gas and He gas coolants. A construction cost of 0.2 million yen/kWe was set up as a design goal. The result is as follows: The sodium reactor has a capability to obtain the goal, and lead-bismuth and gas reactors may satisfy the goal with further improvements. (author)

Prominence Bubble Shear Flows and the Coupled Kelvin-Helmholtz — Rayleigh-Taylor Instability

Science.gov (United States)

Berger, Thomas; Hillier, Andrew

2017-08-01

Prominence bubbles are large arched structures that rise from below into quiescent prominences, often growing to heights on the order of 10 Mm before going unstable and generating plume upflows. While there is general agreement that emerging flux below pre-existing prominences causes the structures, there is lack of agreement on the nature of the bubbles and the cause of the instability flows. One hypothesis is that the bubbles contain coronal temperature plasma and rise into the prominence above due to both magnetic and thermal buoyancy, eventually breaking down via a magnetic Rayleigh-Taylor (RT) instability to release hot plasma and magnetic flux and helicity into the overlying coronal flux rope. Another posits that the bubbles are actually just “arcades” in the prominence indicating a magnetic separator line between the bipole and the prominence fields with the observed upflows and downflows caused by reconnection along the separator. We analyze Hinode/SOT, SDO/AIA, and IRIS observations of prominence bubbles, focusing on characteristics of the bubble boundary layers that may discriminate between the two hypotheses. We find speeds on the order of 10 km/s in prominence plasma downflows and lateral shear flows along the bubble boundary. Inflows to the boundary gradually increase the thickness and brightness of the layer until plasma drains from there, apparently around the dome-like bubble domain. In one case, shear flow across the bubble boundary develops Kelvin-Helmholtz (KH) vortices that we use to infer flow speeds in the low-density bubble on the order of 100 km/sec. IRIS spectra indicate that plasma flows on the bubble boundary at transition region temperatures achieve Doppler speeds on the order of 50 km/s, consistent with this inference. Combined magnetic KH-RT instability analysis leads to flux density estimates of 10 G with a field angle of 30° to the prominence, consistent with vector magnetic field measurements. In contrast, we find no evidence

Ground depositions and air concentrations of Chernobyl fallout radionuclides at Munich-Neuherberg

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, H.; Rosner, G.; Winkler, R.

1987-01-01

Southern Bavaria has received a comparatively high deposition of fallout radionuclides from the reactor accident at Chernobyl. As a result, in addition to the measurement of numerous gamma emitting nuclides and of strontium isotopes, the determination of several actinides, including isotopes of uranium, neptunium, plutonium and curium was possible. The observed radionuclide composition of the fallout and the time course of ground deposition and air concentration at the site of the Gesellschaft fuer Strahlen- und Umweltforschung (GSF) at Neuherberg, 10 km north of Munich, are reported and discussed.

Ground depositions and air concentrations of Chernobyl fallout radionuclides at Munich-Neuherberg

International Nuclear Information System (INIS)

Hoetzl, H.; Rosner, G.; Winkler, R.

1987-01-01

Southern Bavaria has received a comparatively high deposition of fallout radionuclides from the reactor accident at Chernobyl. As a result, in addition to the measurement of numerous gamma emitting nuclides and of strontium isotopes, the determination of several actinides, including isotopes of uranium, neptunium, plutonium and curium was possible. The observed radionuclide composition of the fallout and the time course of ground deposition and air concentration at the site of the Gesellschaft fuer Strahlen- und Umweltforschung (GSF) at Neuherberg, 10 km north of Munich, are reported and discussed. (orig.)

7 CFR 29.1044 - Orange Red (FR).

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Orange Red (FR). 29.1044 Section 29.1044 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1044 Orange Red (FR). A yellowish red. [42 FR 21092, Apr. 25, 1977. Redesignated at 47 FR...

Eröffnung des „Hauses der Astronomie“ auf dem Königsstuhl

OpenAIRE

Pössel, Markus; Tschira, Klaus

2012-01-01

Mit dem „Haus der Astronomie“ (HdA) auf dem Königsstuhl ist ein neues Zentrum für astronomische Bildungs- und Öffentlichkeitsarbeit in Heidelberg eröffnet. Das Haus der Astronomie ist eine gemeinsame Einrichtung der Max-Planck-Gesellschaft (MPG) und der Klaus Tschira Stiftung unter Beteiligung der Stadt Heidelberg und der Ruperto Carola, deren Zentrum für Astronomie eng mit dem HdA zusammenarbeitet. Ziel des HdA ist es, astronomische Forschung einer breiten Öffentlichkeit in verständlicher Fo...

76 FR 25534 - Airworthiness Directives; Hamilton Sundstrand Propellers Model 247F Propellers

Science.gov (United States)

2011-05-05

... 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the... through FR2279 inclusive, FR 2398, FR2449 to FR2958 inclusive, FR20010710 to FR20010722 inclusive, and FR20010723RT to FR20020127RT inclusive, installed. Propeller blades reworked to Hamilton Sundstrand Service...

Future dynamics in f(R) theories

International Nuclear Information System (INIS)

Mueller, D.; Andrade, V.C. de; Maia, C.; Reboucas, M.J.; Teixeira, A.F.F.

2015-01-01

The f(R) gravity theories provide an alternative way to explain the current cosmic acceleration without invoking a dark energy matter component used in the cosmological modeling in the framework of general relativity. However, the freedom in the choice of the functional forms of f(R) gives rise to the problem of the degeneracy among these gravity theories on theoretical and (or) observational grounds. In this paper we examine the question as to whether the future dynamics can be used to break the degeneracy between f(R) gravity theories by investigating the dynamics of spatially homogeneous and isotropic dust flat models in two f(R) gravity theories, namely the well known f(R) = R+αR n gravity and another byAviles et al., whose motivation comes from the cosmographic approach to f(R) gravity. We perform a detailed numerical study of the dynamics of these theories taking into account the recent constraints on the cosmological parameters made by the Planck Collaboration. We demonstrate that besides being useful for discriminating between these two f(R) gravity theories, the future dynamics technique can also be used to determine the finite-time behavior as well as the fate of the Universe in the framework of these f(R) gravity theories. There also emerges from our analysis the result that one still can have a dust flat FLRWsolution with a big rip, if gravity is governed by f(R) = R+αR n . We also show that FLRW dust solutions with f'' < 0 do not necessarily lead to singularities. (orig.)

First test of the prompt gamma ray timing method with heterogeneous targets at a clinical proton therapy facility

International Nuclear Information System (INIS)

Hueso-González, Fernando; Enghardt, Wolfgang; Golnik, Christian; Petzoldt, Johannes; Pausch, Guntram; Fiedler, Fine; Priegnitz, Marlen; Römer, Katja E; Wagner, Andreas; Janssens, Guillaume; Prieels, Damien; Smeets, Julien; Vander Stappen, François

2015-01-01

Ion beam therapy promises enhanced tumour coverage compared to conventional radiotherapy, but particle range uncertainties significantly blunt the achievable precision. Experimental tools for range verification in real-time are not yet available in clinical routine. The prompt gamma ray timing method has been recently proposed as an alternative to collimated imaging systems. The detection times of prompt gamma rays encode essential information about the depth-dose profile thanks to the measurable transit time of ions through matter. In a collaboration between OncoRay, Helmholtz-Zentrum Dresden-Rossendorf and IBA, the first test at a clinical proton accelerator (Westdeutsches Protonentherapiezentrum Essen, Germany) with several detectors and phantoms is performed. The robustness of the method against background and stability of the beam bunch time profile is explored, and the bunch time spread is characterized for different proton energies. For a beam spot with a hundred million protons and a single detector, range differences of 5 mm in defined heterogeneous targets are identified by numerical comparison of the spectrum shape. For higher statistics, range shifts down to 2 mm are detectable. A proton bunch monitor, higher detector throughput and quantitative range retrieval are the upcoming steps towards a clinically applicable prototype. In conclusion, the experimental results highlight the prospects of this straightforward verification method at a clinical pencil beam and settle this novel approach as a promising alternative in the field of in vivo dosimetry. (paper)

ROCK inhibitor primes human induced pluripotent stem cells to selectively differentiate towards mesendodermal lineage via epithelial-mesenchymal transition-like modulation.

Science.gov (United States)

Maldonado, Maricela; Luu, Rebeccah J; Ramos, Michael E P; Nam, Jin

2016-09-01

Robust control of human induced pluripotent stem cell (hIPSC) differentiation is essential to realize its patient-tailored therapeutic potential. Here, we demonstrate a novel application of Y-27632, a small molecule Rho-associated protein kinase (ROCK) inhibitor, to significantly influence the differentiation of hIPSCs in a lineage-specific manner. The application of Y-27632 to hIPSCs resulted in a decrease in actin bundling and disruption of colony formation in a concentration and time-dependent manner. Such changes in cell and colony morphology were associated with decreased expression of E-cadherin, a cell-cell junctional protein, proportional to the increased exposure to Y-27632. Interestingly, gene and protein expression of pluripotency markers such as NANOG and OCT4 were not downregulated by an exposure to Y-27632 up to 36h. Simultaneously, epithelial-to-mesenchymal (EMT) transition markers were upregulated with an exposure to Y-27632. These EMT-like changes in the cells with longer exposure to Y-27632 resulted in a significant increase in the subsequent differentiation efficiency towards mesendodermal lineage. In contrast, an inhibitory effect was observed when cells were subjected to ectodermal differentiation after prolonged exposure to Y-27632. Collectively, these results present a novel method for priming hIPSCs to modulate their differentiation potential with a simple application of Y-27632. Copyright © 2016 Helmholtz Zentrum München. Published by Elsevier B.V. All rights reserved.

The 4th international comparison on EPR dosimetry with tooth enamel

Energy Technology Data Exchange (ETDEWEB)

Fattibene, P., E-mail: paola.fattibene@iss.it [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, Neuherberg D-85764 (Germany); Adolfsson, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Benevides, L.A. [Naval Dosimetry Center, Bethesda MD 20889-5600 (United States); Brai, M. [University of Palermo, I-90128 Palermo (Italy); Callens, F. [Ghent University, B-9000 Gent (Belgium); Chumak, V. [Research Center for Radiation Medicine AMS, 04050 Kiev (Ukraine); Ciesielski, B. [Medical University of Gdansk, 80-211 Gdansk (Poland); Della Monaca, S. [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Regina Elena Institute, I-00144 Rome (Italy); Emerich, K. [Medical University of Gdansk, 80-211 Gdansk (Poland); Department of Paediatric Dentistry, 80-208 Gdansk (Poland); Gustafsson, H. [Linkoeping University, SE-58185 Linkoeping (Sweden); Hirai, Y. [Radiation Effects Research Foundation, Minami-ku, Hiroshima 732-0815 (Japan); Hoshi, M. [Hiroshima University, Minami-ku, Hiroshima 734-8553 (Japan); Israelsson, A. [Linkoeping University, SE-58185 Linkoeping (Sweden); Ivannikov, A. [Medical Radiological Research Center, Obninsk, Kaluga region (Russian Federation); Ivanov, D. [Institute of Metal Physics, Yekaterinburg 620041 (Russian Federation); Kaminska, J. [Medical University of Gdansk, 80-211 Gdansk (Poland); Ke, Wu [Beijing Institute of Radiation Medicine, Beijing 100850 (China); Lund, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Marrale, M. [University of Palermo, I-90128 Palermo (Italy)

2011-09-15

This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Muenchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.

Comparison between wire mesh sensor and gamma densitometry void measurements in two-phase flows

Science.gov (United States)

Sharaf, S.; Da Silva, M.; Hampel, U.; Zippe, C.; Beyer, M.; Azzopardi, B.

2011-10-01

Wire mesh sensors (WMS) are fast imaging instruments that are used for gas-liquid and liquid-liquid two-phase flow measurements and experimental investigations. Experimental tests were conducted at Helmholtz-Zentrum Dresden-Rossendorf to test both the capacitance and conductance WMS against a gamma densitometer (GD). A small gas-liquid test facility was utilized. This consisted of a vertical round pipe approximately 1 m in length, and 50 mm internal diameter. A 16 × 16 WMS was used with high spatial and temporal resolutions. Air-deionized water was the two-phase mixture. The gas superficial velocity was varied between 0.05 m s-1 and 1.4 m s-1 at two liquid velocities of 0.2 and 0.7 m s-1. The GD consisted of a collimated source and a collimated detector. The GD was placed on a moving platform close to the plane of wires of the sensor, in order to align it accurately using a counter mechanism, with each of the wires of the WMS, and the platform could scan the full section of the pipe. The WMS was operated as a conductivity WMS for a half-plane with eight wires and as a capacitance WMS for the other half. For the cross-sectional void (time and space averaged), along each wire, there was good agreement between WMS and the GD chordal void fraction near the centre of the pipe.

Comparison between wire mesh sensor and gamma densitometry void measurements in two-phase flows

International Nuclear Information System (INIS)

Sharaf, S; Azzopardi, B; Da Silva, M; Hampel, U; Zippe, C; Beyer, M

2011-01-01

Wire mesh sensors (WMS) are fast imaging instruments that are used for gas–liquid and liquid–liquid two-phase flow measurements and experimental investigations. Experimental tests were conducted at Helmholtz-Zentrum Dresden-Rossendorf to test both the capacitance and conductance WMS against a gamma densitometer (GD). A small gas–liquid test facility was utilized. This consisted of a vertical round pipe approximately 1 m in length, and 50 mm internal diameter. A 16 × 16 WMS was used with high spatial and temporal resolutions. Air–deionized water was the two-phase mixture. The gas superficial velocity was varied between 0.05 m s −1 and 1.4 m s −1 at two liquid velocities of 0.2 and 0.7 m s −1 . The GD consisted of a collimated source and a collimated detector. The GD was placed on a moving platform close to the plane of wires of the sensor, in order to align it accurately using a counter mechanism, with each of the wires of the WMS, and the platform could scan the full section of the pipe. The WMS was operated as a conductivity WMS for a half-plane with eight wires and as a capacitance WMS for the other half. For the cross-sectional void (time and space averaged), along each wire, there was good agreement between WMS and the GD chordal void fraction near the centre of the pipe

Simulation of a quadrupole resonator

Energy Technology Data Exchange (ETDEWEB)

Kleindienst, Raphael [Helmholtz Zentrum Berlin (Germany)

2013-07-01

Modern particle accelerators often rely on superconducting radio frequency (SRF) technology for accelerating cavities. In particular in CW operation, very high quality factors up into the high range are desirable, since one of the main cost drivers of such an accelerator, the cryogenic refrigeration plant, is inversely proportional to Q{sub 0}. Present day superconducting cavities are generally made of solid Niobium. A possibility to increase the quality factor as well as accelerating fields is to use thin film coated cavities. Apart from Niobium thin films, other superconducting materials, such as MgB{sub 2}, NbN and Nb{sub 3}Sn are promising candidates. Measuring and understanding the RF-properties of superconducting thin films, specifically the surface resistance, is needed to drive forward this development. Currently only few facilities exist capable of measuring the surface resistance of thin films samples with a resolution in the nano-ohm range at the operating frequency of typical cavities(e.g. L-band). A dedicated test stand consisting of a quadrupole resonator is therefore being constructed at the Helmholtz Zentrum Berlin. This system is based on the 400 MHz quadrupole resonator at CERN, with the design adapted to 433 MHz (making available the higher harmonic mode at 1.3 GHz) and optimized with respect to resolution and maximum achievable fields using simulation data obtained with CST Microwave Studio as well as ANSYS. The simulated design is being manufactured. An outlook for future physics runs is given.

MODELING OBSERVED DECAY-LESS OSCILLATIONS AS RESONANTLY ENHANCED KELVIN–HELMHOLTZ VORTICES FROM TRANSVERSE MHD WAVES AND THEIR SEISMOLOGICAL APPLICATION

Energy Technology Data Exchange (ETDEWEB)

Antolin, P.; De Moortel, I. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews, Fife KY16 9SS (United Kingdom); Van Doorsselaere, T. [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Yokoyama, T., E-mail: patrick.antolin@st-andrews.ac.uk [Department of Earth and Planetary Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2016-10-20

In the highly structured solar corona, resonant absorption is an unavoidable mechanism of energy transfer from global transverse MHD waves to local azimuthal Alfvén waves. Due to its localized nature, direct detection of this mechanism is extremely difficult. Yet, it is the leading theory explaining the observed fast damping of the global transverse waves. However, at odds with this theoretical prediction are recent observations that indicate that in the low-amplitude regime such transverse MHD waves can also appear decay-less, a still unsolved phenomenon. Recent numerical work has shown that Kelvin–Helmholtz instabilities (KHI) often accompany transverse MHD waves. In this work, we combine 3D MHD simulations and forward modeling to show that for currently achieved spatial resolution and observed small amplitudes, an apparent decay-less oscillation is obtained. This effect results from the combination of periodic brightenings produced by the KHI and the coherent motion of the KHI vortices amplified by resonant absorption. Such an effect is especially clear in emission lines forming at temperatures that capture the boundary dynamics rather than the core, and reflects the low damping character of the local azimuthal Alfvén waves resonantly coupled to the kink mode. Due to phase mixing, the detected period can vary depending on the emission line, with those sensitive to the boundary having shorter periods than those sensitive to the loop core. This allows us to estimate the density contrast at the boundary.

Cryogenic infrastructure at BESSY II. Inventory and outlook; Kryogene Infrastruktur bei BESSY II. Bestand und Ausblick

Energy Technology Data Exchange (ETDEWEB)

Heling, Svenja; Anders, Wolfgang; Heinrich, Jochen; Hellwig, Axel; Janke, Karsten; Molder, Benjamin; Rotterdam, Stefan [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany)

2017-07-01

The Helmholtz Centre Berlin operates the BESSY II electron storage ring at the Adlershof site. A helium condenser is installed to supply the superconducting wavelength shifter installed in the storage ring with liquid helium. Another liquefier, including a comprehensive cryogenic infrastructure, supplies helium at 1.8 K to several test stands, especially for superconducting cavity resonators. In addition to the operation of the existing plants, a new type of accelerator is currently being set up as part of the bERLinPro project. In order to ensure the required supply of liquid helium, one of the existing helium condensers will be relocated and the plant will be extended by a 10,000 l dewar, three valve boxes, a cold compressor box, a warm pumping station and an 80 K helium system. In addition, the future project BESSY VSR, a further development of the BESSY II storage ring, will see the procurement of a third refrigeration system. A challenge here will be the year-round continuous operation. This paper explains the structure of the plants described above in more detail and provides an insight into the challenges of plant design. Finally, the planned future expansions will be outlined. [German] Das Helmholtz-Zentrum Berlin betreibt am Standort Adlershof u.a. den Elektronenspeicherring BESSY II. Fuer die Versorgung der im Speicherring installierten supraleitenden Wellenlaengenschieber mit Fluessighelium ist ein Heliumverfluessiger installiert. Ein weiterer Verfluessiger, inklusive umfassender kryogener Infrastruktur, versorgt mehrere Teststaende, vor allem fuer supraleitende Hohlraumresonatoren, mit Helium bei 1,8 K. Neben dem Betrieb der existierenden Anlagen wird derzeit ein neuartiger Beschleunigertyp im Rahmen des Pro-jektes bERLinPro aufgebaut. Um die benoetigte Versorgung mit Fluessighelium zu gewaehrleisten, wird einer der bestehenden Heliumverfluessiger umgezogen sowie die Anlage um u.a. einen 10.000 l Dewar, drei Ventilboxen, eine Kaltkompressorbox, einen

77 FR 7968 - Semiannual Regulatory Agenda

Science.gov (United States)

2012-02-13

... Regulation Sequence No. Title Identifier No. 392 Non-Federal Oil and Gas 1024-AD78 Rights. National Park.... Timetable: Action Date FR Cite NPRM 07/00/12 Regulatory Flexibility Analysis Required: Yes. Agency Contact... anaconda, and Beni anaconda. Timetable: Action Date FR Cite ANPRM 01/31/08 73 FR 5784 ANPRM Comment Period...

Knowledge Preservation and Data Collection on FR in China

International Nuclear Information System (INIS)

Zhang Donghui

2013-01-01

China has established the knowledge preservation and data collection system on FR preliminary and some data has been used to design new fast reactor, such as CFR600. • The best way to preserve FR knowledge is to construct a real fast reactor. All of the FR member countries should push FR commercialization forward together. • The agency could push the FR data collaboration based on some necessary roles

75 FR 62333 - Airworthiness Directives; Hamilton Sundstrand Propellers Model 247F Propellers

Science.gov (United States)

2010-10-08

...., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory... that the 247F propeller blades, P/N 817370-1, S/Ns FR2449 to FR2958 inclusive, FR20010710 to FR20010722 inclusive, and FR20010723RT to FR20020127RT inclusive, manufactured since January 1999, might also have...

76 FR 7101 - Airworthiness Directives; Hamilton Sundstrand Propellers Model 247F Propellers

Science.gov (United States)

2011-02-09

..., except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received... blades part number (P/N) 817370-1, S/Ns FR2449 to FR2958 inclusive, FR20010710 to FR20010722 inclusive, and FR20010723RT to FR20020127RT inclusive, before December 31, 2010. We determined that those S/N...

75 FR 19973 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

Science.gov (United States)

2010-04-16

... Municipal Securities Dealer. Agency form number: FR MSD-4 and FR MSD-5. OMB control number: 7100-0100 and... activities as municipal securities dealers. Estimated annual reporting hours: FR MSD-4, 48 hours; and FR MSD-5, 36 hours. Estimated average hours per response: FR MSD-4, 1 hour; and FR MSD- 5, 0.25 hours...

76 FR 54717 - Supervised Securities Holding Companies Registration

Science.gov (United States)

2011-09-02

... other financial statements submitted to the securities holding company's current consolidated supervisor... Y-9ES), The Supplement to the Consolidated Financial Statements for Bank Holding Companies (FR Y-9CS... Companies (FR Y-6), The Report of Foreign Banking Organizations (FR Y-7), The Consolidated Financial...

7 CFR 29.3068 - Tannish-red color (FR).

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Tannish-red color (FR). 29.3068 Section 29.3068 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Type 93) § 29.3068 Tannish-red color (FR). A light red shaded toward tan. [24 FR 8771, Oct. 29, 1959...

f(R) gravity solutions for evolving wormholes

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, Subhra [Presidency University, Department of Mathematics, Kolkata (India); Chakraborty, Subenoy [Jadavpur University, Department of Mathematics, Kolkata (India)

2017-08-15

The scalar-tensor f(R) theory of gravity is considered in the framework of a simple inhomogeneous space-time model. In this research we use the reconstruction technique to look for possible evolving wormhole solutions within viable f(R) gravity formalism. These f(R) models are then constrained so that they are consistent with existing experimental data. Energy conditions related to the matter threading the wormhole are analyzed graphically and are in general found to obey the null energy conditions (NEC) in regions around the throat, while in the limit f(R) = R, NEC can be violated at large in regions around the throat. (orig.)

Exploring plane-symmetric solutions in f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Shamir, M. F., E-mail: farasat.shamir@nu.edu.pk [National University of Computer and Emerging Sciences, Department of Sciences and Humanities (Pakistan)

2016-02-15

The modified theories of gravity, especially the f(R) gravity, have attracted much attention in the last decade. This paper is devoted to exploring plane-symmetric solutions in the context of metric f(R) gravity. We extend the work on static plane-symmetric vacuum solutions in f(R) gravity already available in the literature [1, 2]. The modified field equations are solved using the assumptions of both constant and nonconstant scalar curvature. Some well-known solutions are recovered with power-law and logarithmic forms of f(R) models.

Intercomparison of radiation protection instrumentation in a pulsed neutron field

Energy Technology Data Exchange (ETDEWEB)

Caresana, M., E-mail: marco.caresana@polimi.it [Politecnico di Milano, CESNEF, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Denker, A. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Esposito, A. [IFNF-LNF, FISMEL, via E. Fermi 40, 00044 Frascati (Italy); Ferrarini, M. [CNAO, Via Privata Campeggi, 27100 Pavia (Italy); Golnik, N. [Institute of Metrology and Biomedical Engineering, Warsaw University of Technology, Sw. A. Boboli 8, 02-525 Warsaw (Poland); Hohmann, E. [Paul Scherrer Institut (PSI), Radiation Metrology Section, CH-5232 Villigen PSI (Switzerland); Leuschner, A. [Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22603 Hamburg (Germany); Luszik-Bhadra, M. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Manessi, G. [CERN, 1211 Geneva 23 (Switzerland); University of Liverpool, Department of Physics, L69 7ZE Liverpool (United Kingdom); Mayer, S. [Paul Scherrer Institut (PSI), Radiation Metrology Section, CH-5232 Villigen PSI (Switzerland); Ott, K. [Helmholtz-Zentrum Berlin, BESSYII, Albert-Einstein-Str.15, 12489 Berlin (Germany); Röhrich, J. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Silari, M. [CERN, 1211 Geneva 23 (Switzerland); Trompier, F. [Institute for Radiological Protection and Nuclear Safety, F-92262 Fontenay aux Roses (France); Volnhals, M.; Wielunski, M. [Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg (Germany)

2014-02-11

In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instruments were placed in a reference position and irradiated with neutrons delivered in bursts of different intensity. The analysis of the instrument response as a function of the burst charge (the total electric charge of the protons in the burst shot onto the tungsten target) permitted to assess for each device the dose underestimation due to the time structure of the radiation field. The personal neutron dosemeters were exposed on a standard PMMA slab phantom and the response linearity was evaluated.

Timing of Pulsed Prompt Gamma Rays for Background Discrimination

International Nuclear Information System (INIS)

Hueso-Gonzalez, F.; Golnik, C.; Berthel, M.; Dreyer, A.; Kormoll, T.; Rohling, H.; Pausch, G.; Enghardt, W.; Fiedler, F.; Heidel, K.; Schoene, S.; Schwengner, R.; Wagner, A.

2013-06-01

In the context of particle therapy, particle range verification is a major challenge for the quality assurance of the treatment. One approach is the measurement of the prompt gamma rays resulting from the tissue irradiation. A Compton camera based on several planes of position sensitive gamma ray detectors, together with an imaging algorithm, is expected to reconstruct the prompt gamma ray emission density profile, which is correlated with the dose distribution. At Helmholtz- Zentrum Dresden-Rossendorf (HZDR) and OncoRay, a camera prototype has been developed consisting of two scatter planes (CdZnTe cross strip detectors) and an absorber plane (Lu 2 SiO 5 block detector). The data acquisition is based on VME electronics and handled by software developed on the ROOT platform. The prototype was tested at the linear electron accelerator ELBE at HZDR, which was set up to produce bunched bremsstrahlung photons. Their spectrum has similarities with the one expected from prompt gamma rays in the clinical case, and these are also bunched with the accelerator frequency. The time correlation between the pulsed prompt photons and the measured signals was used for background discrimination, achieving a time resolution of 3 ns (2 ns) FWHM for the CZT (LSO) detector. A time-walk correction was applied for the LSO detector and improved its resolution to 1 ns. In conclusion, the detectors are suitable for time-resolved background discrimination in pulsed clinical particle accelerators. Ongoing tasks are the test of the imaging algorithms and the quantitative comparison with simulations. Further experiments will be performed at proton accelerators. (authors)

CFD simulation of a particle loaded coolant flow in the sump and in the condensation chamber; Entwicklung von CFD-Modellen fuer Wandsieden und Entwicklung hchaufloesender, schneller Roentgentomographie fuer die Analyse von Zweiphasenstroemungen in Brennstabbuendeln

Energy Technology Data Exchange (ETDEWEB)

Krepper, Eckhard; Rzehak, Roland; Barthel, Frank; Franz, Ronald; Hampel, Uwe

2013-07-01

A collaborative project funded by the BMBF in the framework of the R and D program ''Energie 2020+'' by 4 Universities, 2 Research Centres and ANSYS was coordinated by Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The present report describes the contributions of HZDR done from September 2009 to January 2013. The project was directed towards the development and validation of CFD models of boiling processes in PWR in the range from subcooled nucleate boiling up to the critical heat flux. The report describes the developed and used models. Main achievements were a comprehensive study of the boiling process itself and a better description of the interfacial area by coupling of wall boiling with a population balance model. The model extensions are validated and the present capabilities of CFD for wall boiling are investigated. By means of rod bundle experiments was shown that the measured cross sectional averaged values can be reproduced well with a single set of calibrated model parameters for different tests cases. For the reproduction of patterns of void distribution cross sections attention has to be focussed on the modelling of turbulence in the narrow channel. The experimental work was focussed on the investigation of the flow in a rod bundle. Using a rod bundle test rig the turbulent single phase flow field (PIV) and the average gas volume fraction (gamma densitometry) are measured. The timely and spatial resolved gas fraction was measured applying the ''High speed x-ray tomography'', developed in Rossendorf.

MCNPX dosimetry and radiation-induced cancer risk estimation from 18F-FDG pediatric PET at Brazilian population

International Nuclear Information System (INIS)

Mendes, Bruno M.; Fonseca, Telma C.F.; Campos, Tarcisio P.R.

2017-01-01

Positron emission tomography (PET) using 18 F-FDG has increased significantly in pediatric patients. PET with 18 F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of 18 F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of 18 F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from 18 F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The 18 F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

Infrared nanoscopy down to liquid helium temperatures

Science.gov (United States)

Lang, Denny; Döring, Jonathan; Nörenberg, Tobias; Butykai, Ádám; Kézsmárki, István; Schneider, Harald; Winnerl, Stephan; Helm, Manfred; Kehr, Susanne C.; Eng, Lukas M.

2018-03-01

We introduce a scattering-type scanning near-field infrared microscope (s-SNIM) for the local scale near-field sample analysis and spectroscopy from room temperature down to liquid helium (LHe) temperature. The extension of s-SNIM down to T = 5 K is in particular crucial for low-temperature phase transitions, e.g., for the examination of superconductors, as well as low energy excitations. The low temperature (LT) s-SNIM performance is tested with CO2-IR excitation at T = 7 K using a bare Au reference and a structured Si/SiO2-sample. Furthermore, we quantify the impact of local laser heating under the s-SNIM tip apex by monitoring the light-induced ferroelectric-to-paraelectric phase transition of the skyrmion-hosting multiferroic material GaV4S8 at Tc = 42 K. We apply LT s-SNIM to study the spectral response of GaV4S8 and its lateral domain structure in the ferroelectric phase by the mid-IR to THz free-electron laser-light source FELBE at the Helmholtz-Zentrum Dresden-Rossendorf, Germany. Notably, our s-SNIM is based on a non-contact atomic force microscope (AFM) and thus can be complemented in situ by various other AFM techniques, such as topography profiling, piezo-response force microscopy (PFM), and/or Kelvin-probe force microscopy (KPFM). The combination of these methods supports the comprehensive study of the mutual interplay in the topographic, electronic, and optical properties of surfaces from room temperature down to 5 K.

78 FR 37565 - Endangered Species; Issuance of Permits

Science.gov (United States)

2013-06-21

... Living Treasures Wild 77 FR 68809; November January 22, 2013. Animal Park. 16, 2012. 88777A Wild Wonders... 70457; November January 11, 2013. 26, 2012. 713600 Kingdom Of The Mammals. 77 FR 70457; November January... International Center 78 FR 12777; February April 11, 2013. For The Preservation 25, 2013. Of Wild Animals...

Practical dictionary of environment, nature conservation and land use. English-German; Praxis-Woerterbuch Umwelt, Naturschutz und Landnutzungen. Deutsch-Englisch

Energy Technology Data Exchange (ETDEWEB)

Hutter, C.P. (ed.) [Stiftung Europaeisches Naturerbe (Euronatur), Ludwigsburg (Germany); Schreiner, J. [Alfred Toepfer Akademie fuer Naturschutz, Schneverdingen (Germany)

2004-07-01

More than 30,000 English and 30,000 German terms from these subject fields: agriculture, air pollution abatement, biotope conservation, climate protection, ecology, environmental administration, environmental eduction, environmental engineering, environmental ethics, environmental information, environmental policy, environmental research, fishery, forestry, hunting, landscape management, landscape planning, preventive health care, radiation protection, recycling, regional planning, settlement development, soil conservation, water management, waste, wildlife conservation. (orig.) [German] Mehr als 30 000 deutsche und 30 000 englische Stichworte aus den Themenbereichen: Abfall, Artenschutz, Biotopschutz, Bodenschutz, Fischerei, Forstwirtschaft, Gesundheitsvorsorge, Gewaesserschutz, Jagd, Klimaschutz, Landschaftspflege, Landschaftsplanung, Landwirtschaft, Luftreinhaltung, Oekologie, Raumordnung, Siedlungsentwicklung, Strahlenschutz, Umweltbildung, Umweltethik, Umweltforschung, Umweltinformation, Umweltpolitik, Umwelttechnik, Umweltverwaltung, Wasserwirtschaft, Wiederverwertung. (orig.)

Radioactive waste storage. Annual report 1974. [*14 figs. ; 4 tabs. ; 5 refs. *

Energy Technology Data Exchange (ETDEWEB)

Bechthold, W; Diefenbacher, W; Engelmann, H J; Hild, W; Korthaus, E; Krause, H; Schuchardt, M C; Smailos, E; Albrecht, E; Kolditz, H

1975-12-01

This report is a joint effort of Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen and Gesellschaft fuer Kernforschung mbH Karlsruhe, presenting a survey of the work performed in 1974 in the field of disposal of radioactive waste. The mining and construction work is discussed, which was carried out both underground and above at the ASSE Salt Mine near Remlingen and which was done for repair, maintenance and expansion of operation in accordance with its future purpose. Moreover, the report gives information on the present status of research and of its results. Also new storage techniques are reported which are currently in the planning stage.

75 FR 10692 - Maritime Communications

Science.gov (United States)

2010-03-09

...] Maritime Communications ACTION: Final rule; correction. SUMMARY: The Federal Communications Commission published in the Federal Register of February 2, 2010 (75 FR 5241), a document in the Maritime Radio..., 2010 (75 FR 5241) to ensure that its rules governing the Maritime Radio Services continue to promote...

Geodesic congruences in the Palatini f(R) theory

International Nuclear Information System (INIS)

Shojai, Fatimah; Shojai, Ali

2008-01-01

We shall investigate the properties of a congruence of geodesics in the framework of Palatini f(R) theories. We shall evaluate the modified geodesic deviation equation and the Raychaudhuri's equation and show that f(R) Palatini theories do not necessarily lead to attractive forces. Also, we shall study energy condition for f(R) Palatini gravity via a perturbative analysis of the Raychaudhuri's equation.

Nonlinear evolution of f(R) cosmologies. I. Methodology

International Nuclear Information System (INIS)

Oyaizu, Hiroaki

2008-01-01

We introduce the method and the implementation of a cosmological simulation of a class of metric-variation f(R) models that accelerate the cosmological expansion without a cosmological constant and evade solar-system bounds of small-field deviations to general relativity. Such simulations are shown to reduce to solving a nonlinear Poisson equation for the scalar degree of freedom introduced by the f(R) modifications. We detail the method to efficiently solve the nonlinear Poisson equation by using a Newton-Gauss-Seidel relaxation scheme coupled with the multigrid method to accelerate the convergence. The simulations are shown to satisfy tests comparing the simulated outcome to analytical solutions for simple situations, and the dynamics of the simulations are tested with orbital and Zeldovich collapse tests. Finally, we present several static and dynamical simulations using realistic cosmological parameters to highlight the differences between standard physics and f(R) physics. In general, we find that the f(R) modifications result in stronger gravitational attraction that enhances the dark matter power spectrum by ∼20% for large but observationally allowed f(R) modifications. A more detailed study of the nonlinear f(R) effects on the power spectrum are presented in a companion paper.

THE LIFETIME AND POWERS OF FR IIs IN GALAXY CLUSTERS

International Nuclear Information System (INIS)

Antognini, Joe; Bird, Jonathan; Martini, Paul

2012-01-01

We have identified and studied a sample of 151 FR IIs found in brightest cluster galaxies (BCGs) in the MaxBCG cluster catalog with data from FIRST and NVSS. We have compared the radio luminosities and projected lengths of these FR IIs to the projected length distribution of a range of mock catalogs generated by an FR II model and estimate the FR II lifetime to be 1.9 × 10 8 yr. The uncertainty in the lifetime calculation is a factor of two, primarily due to uncertainties in the intracluster medium (ICM) density and the FR II axial ratio. We furthermore measure the jet power distribution of FR IIs in BCGs and find that it is well described by a log-normal distribution with a median power of 1.1 × 10 37 W and a coefficient of variation of 2.2. These jet powers are nearly linearly related to the observed luminosities, and this relation is steeper than many other estimates, although it is dependent on the jet model. We investigate correlations between FR II and cluster properties and find that galaxy luminosity is correlated with jet power. This implies that jet power is also correlated with black hole mass, as the stellar luminosity of a BCG should be a good proxy for its spheroid mass and therefore the black hole mass. Jet power, however, is not correlated with cluster richness, nor is FR II lifetime strongly correlated with any cluster properties. We calculate the enthalpy of the lobes to examine the impact of the FR IIs on the ICM and find that heating due to adiabatic expansion is too small to offset radiative cooling by a factor of at least six. In contrast, the jet power is approximately an order of magnitude larger than required to counteract cooling. We conclude that if feedback from FR IIs offsets cooling of the ICM, then heating must be primarily due to another mechanism associated with FR II expansion.

THE LIFETIME AND POWERS OF FR IIs IN GALAXY CLUSTERS

Energy Technology Data Exchange (ETDEWEB)

Antognini, Joe; Bird, Jonathan; Martini, Paul, E-mail: antognini@astronomy.ohio-state.edu, E-mail: bird@astronomy.ohio-state.edu, E-mail: martini@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States)

2012-09-10

We have identified and studied a sample of 151 FR IIs found in brightest cluster galaxies (BCGs) in the MaxBCG cluster catalog with data from FIRST and NVSS. We have compared the radio luminosities and projected lengths of these FR IIs to the projected length distribution of a range of mock catalogs generated by an FR II model and estimate the FR II lifetime to be 1.9 Multiplication-Sign 10{sup 8} yr. The uncertainty in the lifetime calculation is a factor of two, primarily due to uncertainties in the intracluster medium (ICM) density and the FR II axial ratio. We furthermore measure the jet power distribution of FR IIs in BCGs and find that it is well described by a log-normal distribution with a median power of 1.1 Multiplication-Sign 10{sup 37} W and a coefficient of variation of 2.2. These jet powers are nearly linearly related to the observed luminosities, and this relation is steeper than many other estimates, although it is dependent on the jet model. We investigate correlations between FR II and cluster properties and find that galaxy luminosity is correlated with jet power. This implies that jet power is also correlated with black hole mass, as the stellar luminosity of a BCG should be a good proxy for its spheroid mass and therefore the black hole mass. Jet power, however, is not correlated with cluster richness, nor is FR II lifetime strongly correlated with any cluster properties. We calculate the enthalpy of the lobes to examine the impact of the FR IIs on the ICM and find that heating due to adiabatic expansion is too small to offset radiative cooling by a factor of at least six. In contrast, the jet power is approximately an order of magnitude larger than required to counteract cooling. We conclude that if feedback from FR IIs offsets cooling of the ICM, then heating must be primarily due to another mechanism associated with FR II expansion.

76 FR 40052 - Regulatory Agenda

Science.gov (United States)

2011-07-07

... for Infusion Pumps. 165 Food Labeling: Nutrition 0910-AG56 Labeling for Food Sold in Vending Machines. 166 Food Labeling: Nutrition 0910-AG57 Labeling of Standard Menu Items in Restaurants and Similar... American Recovery and Reinvestment Act of 2009). Timetable: Action Date FR Cite NPRM 07/14/10 75 FR 40867...

75 FR 14131 - Broadband Technology Opportunities Program

Science.gov (United States)

2010-03-24

... electronically through an online application system at http://www.broadbandusa.gov . (75 FR at 3805). NTIA... March 26, 2010. (75 FR 10464, Mar. 8, 2010). NTIA announces this extension in the Application Closing...

Experimental and theoretical investigations of the decays of 206Fr and 208Fr

International Nuclear Information System (INIS)

Ritchie, B.G.

1979-01-01

206 Fr and 208 Fr were mass separated and observed with large-volume semiconductor detectors in calibrated geometries. Alpha, gamma, and electron singles and gamma-gamma and gamma-electron coincidence data were taken. The alpha decay experiments permitted the determination of the alpha branching ratios for 206 208 Fr as well as 205 207 Fr. The method used includes the information obtained from the electron capture decay studies of those nuclei. The alpha branching ratios obtained are generally higher than those reported previously. Energies and half-lives are in general agreement with previous measurements. The alpha measurements also revealed the presence of a heretofore unobserved alpha-emitting isomer in 206 Fr. The isomer has a half-life of 0.7 +- 0.1 seconds, and the energy of the associated alpha decay is 6.930 +- 0.005 MeV. Gamma data taken with the alpha measurements suggest that the isomeric level is 531 keV above the 206 Fr ground state, with the associated alpha decay populating a level at 391 keV in the 202 At nucleus. Measured alpha branching ratios were analyzed with the Rasmussen reduced width formalism. All observed francium decays were deduced to be unhindered. This study produced detailed level schemes for 206 Rn and 208 Rn. The gamma and electron data permitted the determination of internal conversion coefficients, multipolarities, spins, and parities. It appears from systematics that two different bands of states above J/sup π/ = 4+ are populated by in-beam studies. The deduced level scheme of 208 Rn was studied in the interacting boson approximation (IBA) with the computer code PHINT. The level scheme is readily explained with this model up to around 2 MeV. Good agreement between theory and experiment was also obtained for 204 Rn and 206 Rn, but the limited detail in these decay schemes does not provide conclusive evidence for the applicability of the IBA. 28 figures, 10 tables

Dynamics of anisotropic power-law f(R) cosmology

International Nuclear Information System (INIS)

Shamir, M. F.

2016-01-01

Modified theories of gravity have attracted much attention of the researchers in the recent years. In particular, the f(R) theory has been investigated extensively due to important f(R) gravity models in cosmological contexts. This paper is devoted to exploring an anisotropic universe in metric f(R) gravity. A locally rotationally symmetric Bianchi type I cosmological model is considered for this purpose. Exact solutions of modified field equations are obtained for a well-known f(R) gravity model. The energy conditions are also discussed for the model under consideration. The viability of the model is investigated via graphical analysis using the present-day values of cosmological parameters. The model satisfies null energy, weak energy, and dominant energy conditions for a particular range of the anisotropy parameter while the strong energy condition is violated, which shows that the anisotropic universe in f(R) gravity supports the crucial issue of accelerated expansion of the universe.

Dynamics of anisotropic power-law f(R) cosmology

Energy Technology Data Exchange (ETDEWEB)

Shamir, M. F., E-mail: farasat.shamir@nu.edu.pk [National University of Computer and Emerging Sciences, Lahore Campus, Department of Sciences and Humanities (Pakistan)

2016-12-15

Modified theories of gravity have attracted much attention of the researchers in the recent years. In particular, the f(R) theory has been investigated extensively due to important f(R) gravity models in cosmological contexts. This paper is devoted to exploring an anisotropic universe in metric f(R) gravity. A locally rotationally symmetric Bianchi type I cosmological model is considered for this purpose. Exact solutions of modified field equations are obtained for a well-known f(R) gravity model. The energy conditions are also discussed for the model under consideration. The viability of the model is investigated via graphical analysis using the present-day values of cosmological parameters. The model satisfies null energy, weak energy, and dominant energy conditions for a particular range of the anisotropy parameter while the strong energy condition is violated, which shows that the anisotropic universe in f(R) gravity supports the crucial issue of accelerated expansion of the universe.

76 FR 50881 - Required Scale Tests

Science.gov (United States)

2011-08-17

... RIN 0580-AB10 Required Scale Tests AGENCY: Grain Inspection, Packers and Stockyards Administration... required scale tests. Those documents defined ``limited seasonal basis'' incorrectly. This document... 20, 2011 (76 FR 3485) and on April 4, 2011 (76 FR 18348), concerning required scale tests. Those...

Clustering of galaxies with f(R) gravity

Science.gov (United States)

Capozziello, Salvatore; Faizal, Mir; Hameeda, Mir; Pourhassan, Behnam; Salzano, Vincenzo; Upadhyay, Sudhaker

2018-02-01

Based on thermodynamics, we discuss the galactic clustering of expanding Universe by assuming the gravitational interaction through the modified Newton's potential given by f(R) gravity. We compute the corrected N-particle partition function analytically. The corrected partition function leads to more exact equations of state of the system. By assuming that the system follows quasi-equilibrium, we derive the exact distribution function that exhibits the f(R) correction. Moreover, we evaluate the critical temperature and discuss the stability of the system. We observe the effects of correction of f(R) gravity on the power-law behaviour of particle-particle correlation function also. In order to check the feasibility of an f(R) gravity approach to the clustering of galaxies, we compare our results with an observational galaxy cluster catalogue.

Annual report 2011. Institute of Radiochemistry

International Nuclear Information System (INIS)

Bernhard, G.

2011-01-01

The Institute of Radiochemistry (IRC) IS one of the seven institutes of the Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the ''Nuclear Safety Research Program'' of the Helmholtz Association and focused on the topic ''Safety of Nuclear Waste Disposal''. The research objectives are to generate better process understanding and data for the long-term safety analysis of a nuclear waste disposal in the deep geological underground. A better knowledge about the dominating processes essential for radionuclide (actinide) mobilization and immobilization on the molecular level is needed for the assessment of the macroscopic processes which determine the transport and distribution of radioactivity in the environment. Special emphasis is put on the biological mediated transport of long-lived radionuclides in the geosphere and their interaction with different biosystems like biota and human organism for a better calculation of environmental and health risks. Advanced knowledge is needed for description of the processes dominating at the interfaces between geo- and bio-systems related to the distribution of long-lived radionuclides in various bio-systems along the food chain. More than 120 scientists, technicians, and students, working on their Ph.D., diploma, master, or bachelor thesis, were employed at the Institute of Radiochemistry in 2011. About 20 Ph.D. students are working at the institute. Promotion of young scientists is an important requirement to ensure the competence and further excellent scientific results in the discipline of radiochemistry in future times. We accomplished many new scientific results in the past year, which are presented in this Annual Report, and about 50 original papers were published in peer-reviewed international scientific journals. In 2011, the future research profile of the HZDR was under discussion with the aim to focus the research fields and programs. One result of this process was the

Annual report 2011. Institute of Radiochemistry

Energy Technology Data Exchange (ETDEWEB)

Bernhard, G [ed.

2011-07-01

The Institute of Radiochemistry (IRC) IS one of the seven institutes of the Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the ''Nuclear Safety Research Program'' of the Helmholtz Association and focused on the topic ''Safety of Nuclear Waste Disposal''. The research objectives are to generate better process understanding and data for the long-term safety analysis of a nuclear waste disposal in the deep geological underground. A better knowledge about the dominating processes essential for radionuclide (actinide) mobilization and immobilization on the molecular level is needed for the assessment of the macroscopic processes which determine the transport and distribution of radioactivity in the environment. Special emphasis is put on the biological mediated transport of long-lived radionuclides in the geosphere and their interaction with different biosystems like biota and human organism for a better calculation of environmental and health risks. Advanced knowledge is needed for description of the processes dominating at the interfaces between geo- and bio-systems related to the distribution of long-lived radionuclides in various bio-systems along the food chain. More than 120 scientists, technicians, and students, working on their Ph.D., diploma, master, or bachelor thesis, were employed at the Institute of Radiochemistry in 2011. About 20 Ph.D. students are working at the institute. Promotion of young scientists is an important requirement to ensure the competence and further excellent scientific results in the discipline of radiochemistry in future times. We accomplished many new scientific results in the past year, which are presented in this Annual Report, and about 50 original papers were published in peer-reviewed international scientific journals. In 2011, the future research profile of the HZDR was under discussion with the aim to focus the research fields and programs. One result of this process was the

78 FR 1570 - Semiannual Regulatory Agenda

Science.gov (United States)

2013-01-08

... Deregulatory Priorities. Gregory H. Woods, General Counsel. Energy Efficiency and Renewable Energy--Proposed... Action 10/01/12 77 FR 59719 Regulatory Flexibility Analysis Required: Yes. Agency Contact: Stephen Witkowski, Phone: 202 586-7463, Email: stephen[email protected] . RIN: 1904-AB90 [FR Doc. 2012-31497...

Spectroscopy of high spin states in sup(211,212,213)Fr

International Nuclear Information System (INIS)

Byrne, A.P.; Dracoulis, G.D.; Fahlander, C.; Hubel, H.; Poletti, A.R.; Stuchbery, A.E.; Gerl, J.; Davie, R.F.; Poletti, S.J.

1985-08-01

The level structures of 211 Fr, 212 Fr and 213 Fr have been observed to high spins, approx. 28(h/2π) (and excitation energies approx. 8 MeV) using a variety of gamma-ray spectroscopic techniques. The structure of these nuclides is discussed in terms of couplings of single particle states through empirical shell model calculations. Good agreement with experiment is obtained. In 212 Fr and 213 Fr core-excited configurations are required to explain the properties of the highest states. A number of long lived states were observed in each nucleus some of which decay by by enhanced E3 transitions. The E3 transition strengths are discussed

Alpha decay 225Ac→221Fr

International Nuclear Information System (INIS)

Kudrya, S.A.; Sergienko, V.A.; Gorozhankin, V.M.; Gromov, K.Ya.; Malikov, Sh.R.; Malov, L.A.; Fominykh, V.I.; Tsupko-Sitnikov, V.V.; Chumin, V.G.; Yakushev, E.A.

2002-01-01

In-depth investigation of (α-γ)-coincidences at the 225 Ac decay is carried out. Twenty-one new weak γ-rays are found; 18 γ-rays earlier ascribed to the 225 Ac decay are not confirmed. The quantitative analysis of the (α-γ)-coincidences makes it possible to find the intensity of population of 221 Fr levels by the α decay and multipolarities of five weak γ-transitions. The conversion electron spectrum is investigated in the range of 5-24 keV with a high (some 20 eV) energy resolution. A new M1 type 10.6-keV γ-transition is found. The proposed 225 Ac decay scheme includes 31 excited 221 Fr states. Parities are established for 16 of them. Possible spin values are proposed for 221 Fr levels. Properties of excited 221 Fr states are satisfactorily described by the quasiparticle-phonon nuclear model without the assumption of static octupole deformation

75 FR 66762 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

Science.gov (United States)

2010-10-29

... and Salary Surveys. Agency form number: FR 29a,b. OMB control number: 7100-0290. Frequency: FR 29a, annually; FR 29b, on occasion. Reporters: Employers considered competitors for Federal Reserve employees... Institutions Reforms, Recovery and Enforcement Act of 1989 (FIRREA) agencies \\1\\ conduct the FR 29a survey...

75 FR 50763 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2010-08-17

... competitors of the Federal Reserve Board. The data from the surveys primarily are used to determine the... and Salary Surveys. Agency form number: FR 29a,b. OMB control number: 7100-0290. Frequency: FR 29a, annually; FR 29b, on occasion. Reporters: Employers considered competitors for Federal Reserve employees...

78 FR 30327 - Endangered Species; Marine Mammals; Issuance of Permits

Science.gov (United States)

2013-05-22

.... Applicant Federal Register notice Permit issuance date Endangered Species 65816A Lewis Henderson........ 77... FR 24510; April 24, June 1, 2012. 2012. 69106A Lewis Henderson........ 77 FR 24510; April 24, June 1... 11, 2012. 2012. 213382 Virginia Safari Park & 77 FR 26779; May 7, July 21, 2012. Preservation Center...

The German P and T Study: Results and Conclusions in the View of the Contributing Helmholtz Research Centres

International Nuclear Information System (INIS)

Merk, B.; Geist, A.; Knebel, J.; Modolo, G.

2015-01-01

The decision to phase out electric energy production in nuclear power plants in Germany has put some questions on the future of P and T research. The Federal Ministry for Economic Affairs and Energy and the Federal Ministry of Education and Research have launched a study managed by the National Academy of Science and Engineering to answer these questions on a broad scientific basis. The major mandate was to evaluate scientific and technological as well as socio-economic challenges and opportunities of the P and T technology in the view of the phase out decision, both in a national and an international context. The scientific and technological aspects of P and T are analysed with respect to a possible contribution to the management of nuclear waste, using the following structure: - Starting point and boundary conditions - waste amounts and final disposal strategies. - Definition and description of scenarios - possible ways for transmutation; European vs. national. - Technology challenges of P and T - description of the major challenges to be solved on the way to a possible industrial application. - Current status of R and D - discussion of possible transmutation systems, current R and D status of P and T, technology gaps and future research strategies. - Safety aspects - dedicated safety aspects including all steps of the P and T cycle. - International projects and competences in Germany - what is going on around the world and which support could come from the German industry? In parallel, the socio-scientific, the ecologic and the economic aspects have been analysed using expert interviews, group Delphi and independent expert opinions on economic, legal and environmental aspects. An overview of the study's results will be given from the viewpoint of the contributing Helmholtz research centres at Juelich (FZJ), Dresden-Rossendorf (HZDR) and Karlsruhe (KIT), with a focus on the research-political recommendations and the developed research strategy proposed to

ionFR: Ionospheric Faraday rotation [Dataset

NARCIS (Netherlands)

Sotomayor-Beltran, C.; et al., [Unknown; Hessels, J.W.T.; van Leeuwen, J.; Markoff, S.; Wijers, R.A.M.J.

2013-01-01

IonFR calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. The code uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. ionFR can be

78 FR 47412 - Tyson D. Quy, M.D.; Decision and Order

Science.gov (United States)

2013-08-05

... Green, Jr., M.D., 59 FR 51,453 (DEA 1994); David E. Trawick, D.D.S., 53 FR 5,326 (DEA 1988). Here, the...) (ten years); Norman Alpert, M.D., 58 FR 67,420, 67,421 (DEA 1993) (seven years). Here, the conditions...

78 FR 44275 - Semiannual Regulatory Agenda

Science.gov (United States)

2013-07-23

... Rights. National Park Service--Completed Actions Regulation Sequence No. Title Identifier No. 200 Winter.... Timetable: Action Date FR Cite NPRM 07/00/13 Final Action 05/00/14 Regulatory Flexibility Analysis Required...: Action Date FR Cite NPRM 10/00/14 Final Action 10/00/14 Regulatory Flexibility Analysis Required: Yes...

Solar System constraints to general f(R) gravity

International Nuclear Information System (INIS)

Chiba, Takeshi; Smith, Tristan L.; Erickcek, Adrienne L.

2007-01-01

It has been proposed that cosmic acceleration or inflation can be driven by replacing the Einstein-Hilbert action of general relativity with a function f(R) of the Ricci scalar R. Such f(R) gravity theories have been shown to be equivalent to scalar-tensor theories of gravity that are incompatible with Solar System tests of general relativity, as long as the scalar field propagates over Solar System scales. Specifically, the parameterized post-Newtonian (PPN) parameter in the equivalent scalar-tensor theory is γ=1/2, which is far outside the range allowed by observations. In response to a flurry of papers that questioned the equivalence of f(R) theory to scalar-tensor theories, it was recently shown explicitly, without resorting to the scalar-tensor equivalence, that the vacuum field equations for 1/R gravity around a spherically symmetric mass also yield γ=1/2. Here we generalize this analysis to f(R) gravity and enumerate the conditions that, when satisfied by the function f(R), lead to the prediction that γ=1/2

f(R) gravity and chameleon theories

International Nuclear Information System (INIS)

Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine; Shaw, Douglas J.

2008-01-01

We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrained to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory tests imply that f(R) models are almost coincident with a ΛCDM model at the background level.

Alpha decay 225 Ac → 221Fr

International Nuclear Information System (INIS)

Gromov, K. Ya.; Gorozhankin, V.M.; Malov, L.A.; Fominykh, V.I.; Tsupko-Sitnikov, V.V.; Chumin, V.G.; Jakushev, E.A.; Kudrya, S.A.; Sergienko, V.A.; Malikov, Sh.R.

2004-01-01

Full text: Considerable attention has been given to nuclei with A = 220 - 230 recently. In this region there occurs transition from the spherical to the deformed nuclear shape, which gives rise to some specific features in the nuclear structure. In particular, negative parity levels with low excitation energies have been found in even-even nuclei from this region [1, 2]. One of the nuclei allowing experimental investigation of the above properties is 221 Fr. The nuclide 221 Fr is from the region of isotopes which does not include stable nuclei and thus it cannot be studied in several-nucleon transfer reactions. In addition, the neutron excess in this nucleus makes it impossible to study the nucleus in reactions with heavy ions. Experimental information on the 221 Fr level structure can only be gained from investigation of the 225 Ac (T 1/2 = 10 days) alpha decay or the 221 Rn (T 1/2 = 25 min) beta decay. In the latter case the possibilities of the investigation are restricted by difficulties in making of 221 Rn sources. Therefore, most information on the structure and properties of 221 Fr is derived from investigation of the 225 Ac α -decay [3]. In-depth investigation of ( α - γ )- coincidences at the 225 Ac decay is carried out. Twenty-one new weak γ - rays are found; 18 γ-rays earlier ascribed to the 225 Ac decay are not confirmed. The quantitative analysis of the ( α - γ )- coincidences makes it possible to find the intensity of 221 Fr levels by the decay and multipolarities of five weak γ -transitions. The conversion electron spectrum is investigated in the range of 5 † 24 keV with a high (some 20 eV) energy resolution. A new M1 type 10.6-keV γ-transition is found. The proposed 225 Ac decay scheme includes 31 excited 221 Fr states. Parities are established for 16 of them. Possible spin values are proposed for 221 Fr levels. Properties of excited 221 Fr states are satisfactorily described by the quasiparticle-phonon nuclear model without the

Constraint propagation equations of the 3+1 decomposition of f(R) gravity

International Nuclear Information System (INIS)

Paschalidis, Vasileios; Shapiro, Stuart L; Halataei, Seyyed M H; Sawicki, Ignacy

2011-01-01

Theories of gravity other than general relativity (GR) can explain the observed cosmic acceleration without a cosmological constant. One such class of theories of gravity is f(R). Metric f(R) theories have been proven to be equivalent to Brans-Dicke (BD) scalar-tensor gravity without a kinetic term (ω = 0). Using this equivalence and a 3+1 decomposition of the theory, it has been shown that metric f(R) gravity admits a well-posed initial value problem. However, it has not been proven that the 3+1 evolution equations of metric f(R) gravity preserve the (Hamiltonian and momentum) constraints. In this paper, we show that this is indeed the case. In addition, we show that the mathematical form of the constraint propagation equations in BD-equilavent f(R) gravity and in f(R) gravity in both the Jordan and Einstein frames is exactly the same as in the standard ADM 3+1 decomposition of GR. Finally, we point out that current numerical relativity codes can incorporate the 3+1 evolution equations of metric f(R) gravity by modifying the stress-energy tensor and adding an additional scalar field evolution equation. We hope that this work will serve as a starting point for relativists to develop fully dynamical codes for valid f(R) models.

75 FR 57690 - Acquisition Regulation: Sustainable Acquisition

Science.gov (United States)

2010-09-22

... general guidelines issued by OMB. OMB's guidelines were published at 67 FR 8452 (February 22, 2002), and DOE's guidelines were published at 67 FR 62446 (October 7, 2002). DOE has reviewed today's rule under... products. (5) Environmentally preferable and energy efficient electronics including desktop computers...

The 360 Degree Fulldome Production "Clockwork Ocean"

Science.gov (United States)

Baschek, B.; Heinsohn, R.; Opitz, D.; Fischer, T.; Baschek, T.

2016-02-01

The investigation of submesoscale eddies and fronts is one of the leading oceanographic topics at the Ocean Sciences Meeting 2016. In order to observe these small and short-lived phenomena, planes equipped with high-resolution cameras and fast vessels were deployed during the Submesoscale Experiments (SubEx) leading to some of the first high-resolution observations of these eddies. In a future experiment, a zeppelin will be used the first time in marine sciences. The relevance of submesoscale processes for the oceans and the work of the eddy hunters is described in the fascinating 9-minute long 360 degree fulldome production Clockwork Ocean. The fully animated movie is introduced in this presentation taking the observer from the bioluminescence in the deep ocean to a view of our blue planet from space. The immersive media is used to combine fascination for a yet unknown environment with scientific education of a broad audience. Detailed background information is available at the parallax website www.clockwork-ocean.com. The Film is also available for Virtual Reality glasses and smartphones to reach a broader distribution. A unique Mobile Dome with an area of 70 m² and seats for 40 people is used for science education at events, festivals, for politicians and school classes. The spectators are also invited to participate in the experiments by presenting 360 degree footage of the measurements. The premiere of Clockwork Ocean was in July 2015 in Hamburg, Germany and will be worldwide available in English and German as of fall 2015. Clockwork Ocean is a film of the Helmholtz-Zentrum Geesthacht produced by Daniel Opitz and Ralph Heinsohn.

Two-phase flow pattern measurements with a wire mesh sensor in a direct steam generating solar thermal collector

Science.gov (United States)

Berger, Michael; Mokhtar, Marwan; Zahler, Christian; Willert, Daniel; Neuhäuser, Anton; Schleicher, Eckhard

2017-06-01

At Industrial Solar's test facility in Freiburg (Germany), two phase flow patterns have been measured by using a wire mesh sensor from Helmholtz Zentrum Dresden-Rossendorf (HZDR). Main purpose of the measurements was to compare observed two-phase flow patterns with expected flow patterns from models. The two-phase flow pattern is important for the design of direct steam generating solar collectors. Vibrations should be avoided in the peripheral piping, and local dry-outs or large circumferential temperature gradients should be prevented in the absorber tubes. Therefore, the choice of design for operation conditions like mass flow and steam quality are an important step in the engineering process of such a project. Results of a measurement with the wire mesh sensor are the flow pattern and the plug or slug frequency at the given operating conditions. Under the assumption of the collector power, which can be assumed from previous measurements at the same collector and adaption with sun position and incidence angle modifier, also the slip can be evaluated for a wire mesh sensor measurement. Measurements have been performed at different mass flows and pressure levels. Transient behavior has been tested for flashing, change of mass flow, and sudden changes of irradiation (cloud simulation). This paper describes the measurements and the method of evaluation. Results are shown as extruded profiles in top view and in side view. Measurement and model are compared. The tests have been performed at low steam quality, because of the limits of the test facility. Conclusions and implications for possible future measurements at larger collectors are also presented in this paper.

Numerical Simulations of Counter Current Flow Experiments Using a Morphology Detection Algorithm

Directory of Open Access Journals (Sweden)

Thomas Höhne

2012-09-01

Full Text Available In order to improve the understanding of counter-current two-phase flows and to validate new physical models, CFD simulations of 1/3rd scale model of the hot leg of a German Konvoi PWR with rectangular cross section was performed. Selected counter-current flow limitation (CCFL experiments at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR were calculated with ANSYS CFX 12.1 using the multi-fluid Euler-Euler modeling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a SST turbulence model for each phase. In the simulation, the surface drag was approached by a new correlation inside the Algebraic Interfacial Area Density (AIAD model. The AIAD model allows the detection of the morphological form of the two phase flow and the corresponding switching via a blending function of each correlation from one object pair to another. As a result this model can distinguish between bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicated that quantitative agreement of the CCFL characteristics between calculation and experimental data was obtained. To validate the model and to study scaling effects CFD simulations of the CCFL phenomenon in a full scale PWR hot leg of the UPTF test facility were performed. Also these results indicated a good agreement between the calculation and experimental data. The final goal is to provide an easy usable AIAD framework for all ANSYS CFX users, with the possibility of the implementation of their own correlations.

Aperfeiçoamento da técnica de Soldagem Pontual por Fricção (FSpW para união de poliamida 6 e laminado de poliamida 66 com fibra de carbono

Directory of Open Access Journals (Sweden)

Joel Gonçalves

2014-03-01

Full Text Available A Soldagem Pontual por Fricção ('Friction Spot Welding - FSpW' é uma técnica inovadora que foi desenvolvida e patenteada em 2005 pelo centro de pesquisa alemão Helmholtz Zentrum Geesthacht (HZG. A técnica apresenta ciclos rápidos, baixo custo operacional e gera soldas com alto desempenho mecânico. Foi inicialmente projetada para a soldagem de ligas metálicas leves. A soldagem de polímeros é alvo de pesquisas recentes e a soldagem de compósitos poliméricos por FSpW ainda é inédita. Este estudo demonstrou a viabilidade técnica da soldagem de chapa de poliamida 6 (PA6 e laminado de poliamida 66 e fibra de carbono (CF-PA66 por FSpW. O histórico térmico, o acabamento superficial, a microestrutura da região da solda e a resistência mecânica ao cisalhamento de juntas sobrepostas PA6/CF-PA66 foram investigados. O aumento do tamanho do anel de fixação da ferramenta original, projetada para a soldagem de metais, possibilitou a seleção de parâmetros de soldagem que resultaram em grande aporte térmico, resultando no aumento da área soldada, num menor entalhe (inscrição deixado pela ferramenta na amostra, produzindo melhoria no acabamento superficial da solda. Essa otimização resultou em uma junta PA6/CF-PA66 com resistência ao cisalhamento de 35 MPa (2196 N, com fratura predominante na placa superior de PA6.

MCNPX dosimetry and radiation-induced cancer risk estimation from {sup 18}F-FDG pediatric PET at Brazilian population

Energy Technology Data Exchange (ETDEWEB)

Mendes, Bruno M.; Fonseca, Telma C.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Campos, Tarcisio P.R., E-mail: bmm@cdtn.br, E-mail: tcff@cdtn.br, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (PCTN/UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares

2017-07-01

Positron emission tomography (PET) using {sup 18}F-FDG has increased significantly in pediatric patients. PET with {sup 18}F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of {sup 18}F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of {sup 18}F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from {sup 18}F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The {sup 18}F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

TWG-FR Activity Report for the Period May 2011 – May 2012

International Nuclear Information System (INIS)

Monti, Stefano

2012-01-01

Recent Recommendations of the TWG-FR & implementation: ⇨ Increase the efforts to make more countries participating in its activities → Sweden became full member of TWG-FR this year. ⇨ Concentrate all research and technical activities related to FR under the TWG-FR umbrella. An efficient and effective interface between INPRO and TWG-FR should be established to avoid duplication/overlapping of activities → done. ⇨ Closer cooperation links should be established with FR-related activities implemented within the framework of other international programmes (e.g. GIF, INPRO, OECD/NEA, ESNII) → systematic collaboration with INPRO, interface with GIF, participation to NEA-TF on SFR, member of External Advisory Committee of some Euratom projects. ⇨ Continue to secure training and education in the field of Fast Neutron System Physics, Technology and Applications, and respective Schools/Seminars should be held on a regular basis → 4 events: 2 in 2011 and 2 in 2012 (Trieste, Bariloche). ⇨ Launch new CRPs in the field of safety of FR with special emphasis on severe accidents → launch of EBR-II CRP + 4 related Workshops/TMs. ⇨ The IAEA, with technical inputs from the TWG-FR, should produce international safety standards relevant to fast reactors → Initiated discussion with Department of Nuclear Safety and Security + INPRO/GIF for SFR Safety Design Criteria

Effective Dark Matter Halo Catalog in f(R) Gravity.

Science.gov (United States)

He, Jian-Hua; Hawken, Adam J; Li, Baojiu; Guzzo, Luigi

2015-08-14

We introduce the idea of an effective dark matter halo catalog in f(R) gravity, which is built using the effective density field. Using a suite of high resolution N-body simulations, we find that the dynamical properties of halos, such as the distribution of density, velocity dispersion, specific angular momentum and spin, in the effective catalog of f(R) gravity closely mimic those in the cold dark matter model with a cosmological constant (ΛCDM). Thus, when using effective halos, an f(R) model can be viewed as a ΛCDM model. This effective catalog therefore provides a convenient way for studying the baryonic physics, the galaxy halo occupation distribution and even semianalytical galaxy formation in f(R) cosmologies.

基于FrFT-MUSIC的空时频算法%Space-time-frequency Algorithm Based on FrFT-MUSIC

Institute of Scientific and Technical Information of China (English)

张声杰; 刘梅

2011-01-01

针对传统时频分析方法难以对星载分布式合成孔径雷达(SAR)系统中地面目标速度进行准确估计的问题,提出了分数阶傅里叶变换(FrFT)-多重信号分类(MUSIC)空时频方法.利用FrFT获得信号向量并构造空时频分布矩阵；应用该分布矩阵替代传统MUSIC算法中的协方差矩阵,从而求得FrFT- MUSIC空时频谱,通过对谱函数进行搜索估计目标速度.仿真实验表明,该方法的目标速度估计精度高,抗噪声能力强.%The fractional Fourier transform (FrFT)-multipIe signal classification (MUSIC) space-time-frequency algorithm is proposed to solve the problem that it is difficult for the traditional time-frequency analysis method to accurately estimate the ground targets' azimuth speed which is coupled with spaceborne distributed synthetic aperture radar" (SAR). The signal vector is obtained and the space-time-frequency distribution matrix is formed by FrFT. Then, this distribution matrix is used instead of the traditional MUSIC covariance matrix to construct FrFT- MUSIC spectral function. Target speed is estimated by searching. Simulation results show that this algorithm has a high accuracy of parameter estimation and strong resistance to noise.

Revisiting a magnetopause Kelvin-Helmholtz event seen by the MMS spacecraft on 8 September 2015: Large-scale context and wave properties

Science.gov (United States)

Hasegawa, H.; Nakamura, T.; Kitamura, N.; Hoshi, Y.; Saito, Y.; Figueroa-Vinas, A.; Giles, B. L.; Lavraud, B.; Khotyaintsev, Y. V.; Ergun, R.

2017-12-01

The Kelvin-Helmholtz (KH) instability is known to grow along the Earth's magnetopause, but its role in transporting solar wind mass and energy into the magnetosphere is not fully understood. On 8 September 2015, the Magnetospheric Multiscale (MMS) spacecraft, located at the postnoon, southern-hemisphere magnetopause, encountered thin low-shear current sheets at the trailing edge of the KH waves, where KH-induced reconnection, one of the plasma transport processes, was occurring [Eriksson et al., GRL, 2016; Li et al., GRL, 2016]. The event was observed during a prolonged period of northward interplanetary magnetic field, and was characterized by an extended region of the low-latitude boundary layer (LLBL) immediately earthward of the KH unstable magnetopause, which appeared to have been formed through magnetopause reconnection poleward of the cusp. In this LLBL, MMS observed plasma turbulence, another agent for the plasma transport [Stawarz et al., JGR, 2016]. Key features are that (i) significant magnetic shears were seen only at the trailing edges of the KH surface waves, (ii) for both the leading and trailing edge traversals, both field-aligned and anti-field-aligned streaming D-shaped ion populations, which are consistent with reconnection on the southward and northward sides, respectively, of MMS, were observed on either the magnetosheath or LLBL side of the magnetopause, though not always simultaneously, and (iii) the field-aligned Poynting flux was positive in some parts of the LLBL but was negative in other parts. Based on these observations and further wave analysis, we address the questions of how the current sheets at the KH wave trailing edges were generated, and what could have been the driver of the turbulent fluctuations observed within the KH vortices.

Investigation of octupole deformations in the Fr217 nucleus by yrast spectroscopy

International Nuclear Information System (INIS)

Hulne, S.

1988-01-01

The spectroscopic characteristics of the yrast levels of Fr217 are determined. The level scheme up to a value of J = (39/2 + ) for angular momentum and parity is established. The production of the Fr217 nucleus in a heavy ion collision reaction was only possible by using a radioactive Pb210 target. The method for preparing the target is described. The Fr217 nucleus belongs to the category of nuclei showing octupole effects. Mass A = 217 seems to be the lower limit of the region where these effects occur [fr

76 FR 58300 - Affirmative Decisions on Petitions for Modification Granted in Whole or in Part

Science.gov (United States)

2011-09-20

... govern the application, processing, and disposition of petitions for modification. This Federal Register... Affected: 30 CFR 75.1700 (Oil and gas wells). Docket Number: M-2009-005-C. FR Notice: 74 FR 23747 (May 20... CFR 75.1700 (Oil and gas wells). Docket Number: M-2009-006-C. FR Notice: 74 FR 23748 (May 20, 2009...

f(R) gravity, torsion and non-metricity

International Nuclear Information System (INIS)

Sotiriou, Thomas P

2009-01-01

For both f(R) theories of gravity with an independent symmetric connection (no torsion), usually referred to as Palatini f(R) gravity theories, and for f(R) theories of gravity with torsion but no non-metricity, called U4 theories, it has been shown that the independent connection can actually be eliminated algebraically, as long as this connection does not couple to matter. Remarkably, the outcome in both cases is the same theory, which is dynamically equivalent with an ω 0 = -3/2 Brans-Dicke theory. It is shown here that even for the most general case of an independent connection with both non-metricity and torsion, one arrives at exactly the same theory as in the more restricted cases. This generalizes the previous results and explains why assuming that either the torsion or the non-metricity vanishing ultimately leads to the same theory. It also demonstrates that f(R) actions cannot support an independent connection which carries dynamical degrees of freedom, irrespective of how general this connection is, at least as long as there is no connection-matter coupling. (fast track communication)

77 FR 32881 - Supervised Securities Holding Company Registration

Science.gov (United States)

2012-06-04

...), The Report of Foreign Banking Organizations (FR Y-7), The Consolidated Financial Statements for Bank... Y-9ES), The Supplement to the Consolidated Financial Statements for Bank Holding Companies (FR Y-9CS... comprehensive consolidated supervision by a foreign regulator, a nonbank financial company supervised by the...

Le developpement de Limacella glioderma (Fr.) R. Maire

NARCIS (Netherlands)

Reijnders, A.F.M.

1979-01-01

A comparison of the development of Limacella guttata (Fr.) Konrad & Maublanc with that of L. glioderma (Fr.) R. Maire shows clearly that the latter is of a more primitive type. This conclusion is based on the following observations: a. Limacella guttata has a pileocarpic development: the first

77 FR 62150 - Approval and Promulgation of Implementation Plans; Kentucky; Approval of Revisions to the...

Science.gov (United States)

2012-10-12

....34 Standard of 10/23/01 66 FR 53661 05/15/91 Performance for Existing Pneumatic Rubber Tire... Abbreviations and 11/19/02 67 FR 69688 05/15/02 Acronyms. 1.04 Performance Tests... 10/23/01 66 FR 53660 11/19... 10/23/01 66 FR 53660 06/13/79 Requirements. Reg 6--Standards of Performance for Existing Affected...

78 FR 6107 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

Science.gov (United States)

2013-01-29

... Derivatives Market Activity (FR 3036; OMB No. 7100-0285). The FR 2436 collects similar data on the outstanding... of Foreign Exchange and Derivative Market Activity. Agency form number: FR 3036. OMB control number... and derivatives market and dealers. Estimated annual reporting hours: Turnover Survey, 2,275 hours...

Role of the Kelvin-Helmholtz instability in the evolution of magnetized relativistic sheared plasma flows.

Science.gov (United States)

Hamlin, Nathaniel D; Newman, William I

2013-04-01

We explore, via analytical and numerical methods, the Kelvin-Helmholtz (KH) instability in relativistic magnetized plasmas, with applications to astrophysical jets. We solve the single-fluid relativistic magnetohydrodynamic (RMHD) equations in conservative form using a scheme which is fourth order in space and time. To recover the primitive RMHD variables, we use a highly accurate, rapidly convergent algorithm which improves upon such schemes as the Newton-Raphson method. Although the exact RMHD equations are marginally stable, numerical discretization renders them unstable. We include numerical viscosity to restore numerical stability. In relativistic flows, diffusion can lead to a mathematical anomaly associated with frame transformations. However, in our KH studies, we remain in the rest frame of the system, and therefore do not encounter this anomaly. We use a two-dimensional slab geometry with periodic boundary conditions in both directions. The initial unperturbed velocity peaks along the central axis and vanishes asymptotically at the transverse boundaries. Remaining unperturbed quantities are uniform, with a flow-aligned unperturbed magnetic field. The early evolution in the nonlinear regime corresponds to the formation of counter-rotating vortices, connected by filaments, which persist in the absence of a magnetic field. A magnetic field inhibits the vortices through a series of stages, namely, field amplification, vortex disruption, turbulent breakdown, and an approach to a flow-aligned equilibrium configuration. Similar stages have been discussed in MHD literature. We examine how and to what extent these stages manifest in RMHD for a set of representative field strengths. To characterize field strength, we define a relativistic extension of the Alfvénic Mach number M(A). We observe close complementarity between flow and magnetic field behavior. Weaker fields exhibit more vortex rotation, magnetic reconnection, jet broadening, and intermediate turbulence

In situ investigations on the impact of heat production and gamma radiation with regard to high-level radioactive waste disposal in rock salt formations

International Nuclear Information System (INIS)

Rothfuchs, T.

1986-01-01

Deep geological formations especially rock salt formations, are considered worldwide as suitable media for the final disposal of radioactive high-level waste (HLW). In the Federal Republic of Germany, the Institut fur Tieflagerung of the Gesellschaft fur Strahlen- und Umweltforschung mbH Munchen operates the Asse Salt Mine as a pilot facility for testing the behavior of an underground nuclear waste repository. The tests are performed using heat and radiation sources to simulate disposed HLW canisters. The measured data obtained since 1965 show that the thermomechanical response of the salt formation and the physical/chemical changes in the vicinity of disposal boreholes are not a serious concern and that their long-term consequences can be estimated based on theoretical considerations and in-situ investigations

Annual report 1974

International Nuclear Information System (INIS)

1975-07-01

The report gives a survey of the activities of the Institut fuer Radiometrie of the Gesellschaft fuer Strahlen- und Umweltforschung mbH, Muenchen, in 1974. The long-term studies on flow models were finished, and new groundwater flow models were established on the basis of their results. Apart from apparative and methodical work for isotope hydrology studies, the work on melting processes in snow blankets and the water balance in glacier regions was continued. Plant materials were investigated as a contribution to palaeoclimatical studies. Furthermore, extensive borchole-meter measurements were carried out in some regions in connection with groundwater securing and protection. The knowledge gained so far concerning the hydrological situation of the region was supplemented by tritium measurements in the Asse groundwaters. (ORU) [de

Annual report 1975

International Nuclear Information System (INIS)

Godt, K.J.

1976-05-01

The 7th annual report of the Institut fuer Strahlenschutz of the Gesellschaft fuer Strahlen- und Umweltforschung mbH gives information on targets and results in the year 1975. The tasks in the fields of radiation protection research and radiation protection services have increased considerably during this year. Aside from problems of radiation protection in connection with the increasing use of nuclear energy, attempts have been made to improve radiation protection in medicine, in particular in the field of X-ray diagnostics. The elaboration of concepts, recommendations and comments on basic problems as well as the practical implementation of the X-ray ordinances and advice to the authorities still make up a major part of the programme of activities. (ORU) [de

75 FR 30003 - Privacy Act of 1974; System of Records

Science.gov (United States)

2010-05-28

... and title, by any of the following methods: * Federal Rulemaking Portal: http://www.regulations.gov..., 2006; 71 FR 35342) and OPM/GOVT-5, Recruiting, Examining, and Placement Records (June 19, 2006; 71 FR...

Development of Streptomyces sp. FR-008 as an emerging chassis

Directory of Open Access Journals (Sweden)

Qian Liu

2016-09-01

Full Text Available Microbial-derived natural products are important in both the pharmaceutical industry and academic research. As the metabolic potential of original producer especially Streptomyces is often limited by slow growth rate, complicated cultivation profile, and unfeasible genetic manipulation, so exploring a Streptomyces as a super industrial chassis is valuable and urgent. Streptomyces sp. FR-008 is a fast-growing microorganism and can also produce a considerable amount of macrolide candicidin via modular polyketide synthase. In this study, we evaluated Streptomyces sp. FR-008 as a potential industrial-production chassis. First, PacBio sequencing and transcriptome analyses indicated that the Streptomyces sp. FR-008 genome size is 7.26 Mb, which represents one of the smallest of currently sequenced Streptomyces genomes. In addition, we simplified the conjugation procedure without heat-shock and pre-germination treatments but with high conjugation efficiency, suggesting it is inherently capable of accepting heterologous DNA. In addition, a series of promoters selected from literatures was assessed based on GusA activity in Streptomyces sp. FR-008. Compared with the common used promoter ermE*-p, the strength of these promoters comprise a library with a constitutive range of 60–860%, thus providing the useful regulatory elements for future genetic engineering purpose. In order to minimum the genome, we also target deleted three endogenous polyketide synthase (PKS gene clusters to generate a mutant LQ3. LQ3 is thus an “updated” version of Streptomyces sp. FR-008, producing fewer secondary metabolites profiles than Streptomyces sp. FR-008. We believe this work could facilitate further development of Streptomyces sp. FR-008 for use in biotechnological applications.

Watermelon germplasm lines USVL246-FR2 and USVL252-FR2 tolerant to fusarium oxysporum f. sp. niveum race 2

Science.gov (United States)

Two improved germplasm lines of wild watermelon (Citrullus lanatus var. citroides) designated USVL246-FR2 and USVL252-FR2 were released in 2012 by the Agricultural Research Service of the U.S. Department of Agriculture (Wechter et al. 2012). These lines are each highly uniform for growth characteri...

f(R) gravity cosmology in scalar degree of freedom

International Nuclear Information System (INIS)

Goswami, Umananda Dev; Deka, Kabita

2014-01-01

The models of f(R) gravity belong to an important class of modified gravity models where the late time cosmic accelerated expansion is considered as the manifestation of the large scale modification of the force of gravity. f(R) gravity models can be expressed in terms of a scalar degree of freedom by explicit redefinition of model's variable. Here we report about the study of the features of cosmological parameters and hence the cosmological evolution using the scalar degree of freedom of the f(R) = ξR n gravity model in the Friedmann-Lemaître-Robertson-Walker (FLRW) background

76 FR 27904 - Approval and Promulgation of Air Quality Implementation Plans; Indiana

Science.gov (United States)

2011-05-13

... Web site is an ``anonymous access'' system, which means EPA will not know your identity or contact... ``Qualified observer'' defined 9/26/1980 11/5/1981, 46 FR 54943. 1-2-62.1 ``Quench car'' defined 6/11/1993 6/15/1995, 60 FR 31412. 1-2-63 Quenching 9/26/1980 11/5/1981, 46 FR 54943. 1-2-63.1 ``Quench reservoir...

75 FR 6112 - Approval and Promulgation of Air Quality Implementation Plans; Georgia: Update to Materials...

Science.gov (United States)

2010-02-08

...) Incinerators........ 6/15/98 12/2/99, 64 FR 67491 391-3-1-.02(2)(d) Fuel-burning 1/17/79 9/18/79, 44 FR 54047...-.02(2)(aa) VOC Emissions from 1/9/91 10/13/92, 57 FR 46780 Wire Coating. 391-3-1-.02(2)(bb) Petroleum...)(lll) NOX Emissions from 2/16/00 7/10/01, 66 FR 35906 Fuel-burning Equipment. 391-3-1-.02(2)(mmm) NOX...

77 FR 59244 - Agency Information Collection Activities; Extension of Currently-Approved Information Collection...

Science.gov (United States)

2012-09-26

... September 30, 1998 (63 FR 52192). Pursuant to this authority, the BTS, now part of the Research and... transferred the responsibility for the F&OS program from BTS to FMCSA (69 FR 51009). On August 10, 2006 (71 FR... financial and statistical reporting regulations of BTS formerly located in chapter XI of title 49 CFR to...

Reduction of FR900525 using an S-(2-aminoethyl) l-cysteine-resistant mutant.

Science.gov (United States)

Shimizu, Shiho; Futase, Ayako; Yokoyama, Tatsuya; Ueda, Satoshi; Honda, Hiroyuki

2017-06-01

FK506 (tacrolimus), a macrolide compound with immunosuppressant activity, has been proven to have clinical importance and has been manufactured industrially since 1993 by using mutants with high FK506-production ability; these mutants have been developed from the wild strain Streptomyces tsukubaensis No. 9993. FR900525 is one of the by-products of FK506 production. However, there was no effective industrial method to separate FR900525 from FK506 due to the structural similarity between the two compounds. Therefore, reducing the level of FR900525 was a serious problem in the industrial strain A. In this study, we aimed to reduce the FR900525 production. We first determined that pipecolic acid level was a critical parameter for controlling FR900525 production in strain A. S-(2-Aminoethyl) l-cysteine (AEC)-resistant mutants has been reported to increase lysine productivity successfully in a variety of lysine-producing microorganisms. Therefore, next, we applied a selection of AEC-resistant mutants to enhance pipecolic acid biosynthesis. Finally, four AEC-resistant mutants were obtained from strain A using ultraviolet irradiation, and three of them showed less FR900525 productivity compared to the parental strain A. Our findings indicated that AEC resistance was effective phenotype marker for increasing pipecolic acid productivity and for reducing FR900525 production in S. tsukubaensis. Thus, our study provides an efficient method for reducing FR90025 level during FK506 biosynthesis. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Mafic rocks from Erinpura gneiss terrane in the Sirohi region ...

Indian Academy of Sciences (India)

1Department of Geology, University of Rajasthan, Jaipur 302 004, India. 2GeoZentrum .... from massive to foliated types wherein the gener- ally steep foliations show ... ered for kinematic analyses of the shear movement. These features are ...

Multidimensional evaluation on FR cycle systems

International Nuclear Information System (INIS)

Nakai, Ryodai; Fujii, Sumio; Takakuma, Katsuyuki; Katoh, Atsushi; Ono, Kiyoshi; Ohtaki, Akira; Shiotani, Hiroki

2004-01-01

This report explains some results of the multidimensional evaluation on various fast reactor cycle system concepts from an interim report of the 2nd phase of ''Feasibility Study on Commercialized FR Cycle System''. This method is designed to give more objective and more quantitative evaluations to clarify commercialized system candidate concepts. Here we brief current evaluation method from the five viewpoints of safety, economy, environment, resource and non-proliferation, with some trial evaluation results for some cycles consist of promising technologies in reactor, core and fuel, reprocessing and fuel manufacture. Moreover, we describe FR cycle deployment scenarios which describe advantages and disadvantages of the cycles from the viewpoints of uranium resource and radioactive waste based on long-term nuclear material mass flow analyses and advantages of the deployment of FR cycle itself from the viewpoints of the comparison with alternative power supplies as well as cost and benefit. (author)

A=225 implantation for $^{221}$Fr source for TRIUMF atom trap

CERN Multimedia

The FrPNC Collaboration is mounting an atom trap for parity violation experiments and precision spectroscopy on francium atoms at TRIUMF's ISAC facility. We would like to use ISOLDE's capability of simultaneously implanting A=225 (while another experiment runs online) to make a long-lived source feeding $^{221}$Fr for tests of the trap. $^{225}$Ra $\\beta$-decays to $^{225}$Ac, which then $\\alpha$-decays, producing 100 keV $^{221}$Fr t$_{1/2}$= 4.8 minute recoils. The implanted A=225 source would be shipped to TRIUMF, where it would be held for several minutes at a time a few mm from the same yttrium foil that normally receives the ISAC beam. SRIM calculations imply that 20% of the $^{221}$Fr will be implanted in a 1 cm diameter spot on the yttrium. Then the yttrium foil is moved to the trap and heated to release the Fr atoms, just as in normal ISAC online operation. A test implantation will be done at 10$^{7}$/sec production for 1 day, testing whether carbon cracking on the implantation foil in the mass separ...

78 FR 34120 - Endangered Species; Marine Mammals; Issuance of Permits

Science.gov (United States)

2013-06-06

..., 2012 October 22, 2012. 73893A A.C. Ranch 77 FR 46514; August 3, September 27, 2012. 2012. 75535A Dub...; August 3, September 27, 2012. 2012. 75592A Dub Wallace Ranch LLC..... 77 FR 46514; August 3, September 27...

Annual report 2011. Institute of Radiochemistry

Energy Technology Data Exchange (ETDEWEB)

Bernhard, G. (ed.)

2011-07-01

The Institute of Radiochemistry (IRC) IS one of the seven institutes of the Helmholtz- Zentrum Dresden-Rossendorf (HZDR). The research activities are fully integrated into the ''Nuclear Safety Research Program'' of the Helmholtz Association and focused on the topic ''Safety of Nuclear Waste Disposal''. The research objectives are to generate better process understanding and data for the long-term safety analysis of a nuclear waste disposal in the deep geological underground. A better knowledge about the dominating processes essential for radionuclide (actinide) mobilization and immobilization on the molecular level is needed for the assessment of the macroscopic processes which determine the transport and distribution of radioactivity in the environment. Special emphasis is put on the biological mediated transport of long-lived radionuclides in the geosphere and their interaction with different biosystems like biota and human organism for a better calculation of environmental and health risks. Advanced knowledge is needed for description of the processes dominating at the interfaces between geo- and bio-systems related to the distribution of long-lived radionuclides in various bio-systems along the food chain. More than 120 scientists, technicians, and students, working on their Ph.D., diploma, master, or bachelor thesis, were employed at the Institute of Radiochemistry in 2011. About 20 Ph.D. students are working at the institute. Promotion of young scientists is an important requirement to ensure the competence and further excellent scientific results in the discipline of radiochemistry in future times. We accomplished many new scientific results in the past year, which are presented in this Annual Report, and about 50 original papers were published in peer-reviewed international scientific journals. In 2011, the future research profile of the HZDR was under discussion with the aim to focus the research fields and programs

Possible antigravity regions in F(R) theory?

Energy Technology Data Exchange (ETDEWEB)

Bamba, Kazuharu, E-mail: bamba@kmi.nagoya-u.ac.jp [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D., E-mail: odintsov@ieec.uab.es [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona (Spain); Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Kievskaya Avenue, 60, 634061, Tomsk (Russian Federation); Sáez-Gómez, Diego, E-mail: diego.saezgomez@uct.ac.za [Astrophysics, Cosmology and Gravity Centre (ACGC) and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Fisika Teorikoaren eta Zientziaren Historia Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 Posta Kutxatila, 48080 Bilbao (Spain)

2014-03-07

We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

Holographic dark energy and f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Aghamohammadi, A [Faculty of Science, Islamic Azad University of Sanandaj, Sanandaj (Iran, Islamic Republic of); Saaidi, Kh, E-mail: ksaaidi@uok.ac.ir, E-mail: agha35484@yahoo.com [Department of Physics, Faculty of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2011-02-15

We investigate the corresponding relation between f(R) gravity and holographic dark energy. We introduce a type of energy density from f(R) that has the same role as holographic dark energy. We obtain the differential equation that specifies the evolution of the introduced energy density parameter based on a varying gravitational constant. We discover the relation for the equation of state parameter for low redshifts that contains varying G correction.

Possible antigravity regions in F(R) theory?

Science.gov (United States)

Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D.; Sáez-Gómez, Diego

2014-03-01

We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

Possible antigravity regions in F(R) theory?

International Nuclear Information System (INIS)

Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D.; Sáez-Gómez, Diego

2014-01-01

We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

78 FR 48932 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2013-08-12

... make corresponding revisions to the Consolidated Financial Statements for Holding Companies (FR Y-9C... Parent Company Only Financial Statements for Holding Companies (FR Y-9SP). DATES: Comments must be... the Federal Financial Institutions Examination Council (FFIEC), have approved the publication for...

Cosmological reconstruction of realistic modified F(R) gravities

International Nuclear Information System (INIS)

Nojiri, Shin'ichi; Odintsov, Sergei D.; Saez-Gomez, Diego

2009-01-01

The cosmological reconstruction scheme for modified F(R) gravity is developed in terms of e-folding (or, redshift). It is demonstrated how any FRW cosmology may emerge from specific F(R) theory. The specific examples of well-known cosmological evolution are reconstructed, including ΛCDM cosmology, deceleration with transition to phantom superacceleration era which may develop singularity or be transient. The application of this scheme to viable F(R) gravities unifying inflation with dark energy era is proposed. The additional reconstruction of such models leads to non-leading gravitational correction mainly relevant at the early/late universe and helping to pass the cosmological bounds (if necessary). It is also shown how cosmological reconstruction scheme may be generalized in the presence of scalar field.

High-performance pickups for beam diagnostics. Design, analysis, characterization and implementation

International Nuclear Information System (INIS)

Angelovski, Aleksandar

2015-01-01

This work introduces the design, analysis, characterization and implementation of high-performance pickups for two beam diagnostic instruments, a Bunch Arrival-time Monitor (BAM) and an Energy Beam Position Monitor (EBPM) at the European XFEL. As a part of the BAM the cone-shaped pickups are proposed along with the corresponding RF-frontend. The designed pickups deliver a beam induced signal with a slope steepness of around 400 mV/ps and a bandwidth of 40 GHz. These signal characteristics are well inside the design requirements, i.e., a slope steepness of 300 mV/ps and more than ten times better compared to the signal from the state-of-the-art pickups. The pickups are installed and commissioned at three accelerator facilities, FLASH at DESY, the quasi-CW SRF accelerator ELBE at the Helmholtz-Zentrum Dresden-Rossendorf and the SwissFEL injector test facility at Paul Scherrer Institute. The obtained measurement results from the installed pickups are in good agreement with the simulations. A comparison between the signal measurements with the cone-shaped pickup and the state-of-the-art is performed at ELBE showing an improvement by a factor of ten. The potential of the pickups for sub-10 fs arrival-time measurements for bunch charges of 20 pC is demonstrated at ELBE and at SwissFEL injector test facility. The introduced coneshaped pickups are the first commercially available pickups with a bandwidth of up to 40 GHz. For the EBPM, a modular pickup structure with two types of planar pickups, microstrip transmission line and grounded coplanar waveguide with perpendicular connectors is investigated. The transition region between the connector and the line is optimized for two substrate materials, alumina and glass with a reflection coefficient better than -20 dB up to 6 GHz.

Reliability of a new biokinetic model of zirconium in internal dosimetry: part II, parameter sensitivity analysis.

Science.gov (United States)

Li, Wei Bo; Greiter, Matthias; Oeh, Uwe; Hoeschen, Christoph

2011-12-01

The reliability of biokinetic models is essential for the assessment of internal doses and a radiation risk analysis for the public and occupational workers exposed to radionuclides. In the present study, a method for assessing the reliability of biokinetic models by means of uncertainty and sensitivity analysis was developed. In the first part of the paper, the parameter uncertainty was analyzed for two biokinetic models of zirconium (Zr); one was reported by the International Commission on Radiological Protection (ICRP), and one was developed at the Helmholtz Zentrum München-German Research Center for Environmental Health (HMGU). In the second part of the paper, the parameter uncertainties and distributions of the Zr biokinetic models evaluated in Part I are used as the model inputs for identifying the most influential parameters in the models. Furthermore, the most influential model parameter on the integral of the radioactivity of Zr over 50 y in source organs after ingestion was identified. The results of the systemic HMGU Zr model showed that over the first 10 d, the parameters of transfer rates between blood and other soft tissues have the largest influence on the content of Zr in the blood and the daily urinary excretion; however, after day 1,000, the transfer rate from bone to blood becomes dominant. For the retention in bone, the transfer rate from blood to bone surfaces has the most influence out to the endpoint of the simulation; the transfer rate from blood to the upper larger intestine contributes a lot in the later days; i.e., after day 300. The alimentary tract absorption factor (fA) influences mostly the integral of radioactivity of Zr in most source organs after ingestion.

The genesis of Jan Steens painting 'As the old ones sing, so the young ones pipe' from the Gemaeldegalerie Berlin

International Nuclear Information System (INIS)

Denker, A.; Kleinert, K.; Laurenze-Landsberg, C.; Reimelt, M.; Schroeder-Smeibidl, B.

2011-01-01

In collaboration with the research reactor of the Helmholtz-Zentrum Berlin fuer Materialien und Energie, the Gemaeldegalerie Berlin is the only institute worldwide, which systematically employs the method of Neutron-Activation-Autoradiography to analyze paintings and painting techniques. To date more than 70 paintings were investigated with this effective, non-destructive, and exceptional method. It allows the visualization of structures and layers beneath the top surface and, in addition, enables the identification of elements contained in the pigments. The instrument B8 at the research reactor BER II is dedicated to this research. Jan Steen is one of the prolific artists from the 17th century. Like other artists from that time he produced several versions of one specific topic during life-time. The topic 'As the old ones sing, so the young ones pipe' was painted by Jan Steen in 13 versions. The painting from the Gemaeldegalerie is an exception in this series as it differs in style and content from the other oeuvres. The question arises: why did the artist deviate from his usual scheme? The possible answer is provided by X-ray images and neutron autoradiographs made of the painting, allowing insight into hidden paint layers and, therefore, in the genesis of the painting. Jan Steen did not simply change the composition of the room and the figures. He originally intended an altogether different topic. Assumedly it was supposed to be a so-called merry company, located in a generous, stately room. Many pieces of this sophisticated ambiance have been eliminated from the version visible today; others were modified and integrated into the composition of the new painting. Thus, Jan Steen commenced the topic 'As the old ones sing, so the young ones pipe' from a different context.

Integrative radiation systems biology

International Nuclear Information System (INIS)

Unger, Kristian

2014-01-01

Maximisation of the ratio of normal tissue preservation and tumour cell reduction is the main concept of radiotherapy alone or combined with chemo-, immuno- or biologically targeted therapy. The foremost parameter influencing this ratio is radiation sensitivity and its modulation towards a more efficient killing of tumour cells and a better preservation of normal tissue at the same time is the overall aim of modern therapy schemas. Nevertheless, this requires a deep understanding of the molecular mechanisms of radiation sensitivity in order to identify its key players as potential therapeutic targets. Moreover, the success of conventional approaches that tried to statistically associate altered radiation sensitivity with any molecular phenotype such as gene expression proofed to be somewhat limited since the number of clinically used targets is rather sparse. However, currently a paradigm shift is taking place from pure frequentistic association analysis to the rather holistic systems biology approach that seeks to mathematically model the system to be investigated and to allow the prediction of an altered phenotype as the function of one single or a signature of biomarkers. Integrative systems biology also considers the data from different molecular levels such as the genome, transcriptome or proteome in order to partially or fully comprehend the causal chain of molecular mechanisms. An example for the application of this concept currently carried out at the Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer” of the Helmholtz-Zentrum München and the LMU Munich is described. This review article strives for providing a compact overview on the state of the art of systems biology, its actual challenges, potential applications, chances and limitations in radiation oncology research working towards improved personalised therapy concepts using this relatively new methodology

Photo-neutron reaction cross-section for 93Nb in the end-point bremsstrahlung energies of 12–16 and 45–70 MeV

International Nuclear Information System (INIS)

Naik, H.; Kim, G.N.; Schwengner, R.; Kim, K.; Zaman, M.; Tatari, M.; Sahid, M.; Yang, S.C.; John, R.; Massarczyk, R.; Junghans, A.; Shin, S.G.; Key, Y.; Wagner, A.; Lee, M.W.; Goswami, A.; Cho, M.-H.

2013-01-01

The photo-neutron cross-sections of 93 Nb at the end-point bremsstrahlung energies of 12, 14 and 16 MeV as well as 45, 50, 55, 60 and 70 MeV have been determined by the activation and the off-line γ-ray spectrometric techniques using the 20 MeV electron linac (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany, and 100 MeV electron linac at Pohang Accelerator Laboratory (PAL), Pohang, Korea. The 93 Nb(γ, xn, x=1–4) reaction cross-sections as a function of photon energy were also calculated using computer code TALYS 1.4. The flux-weighted average values were obtained from the experimental and the theoretical (TALYS) values based on mono-energetic photons. The experimental values of present work are in good agreement with the flux-weighted theoretical values of TALYS 1.4 but are slightly higher than the flux-weighted experimental data of mono-energetic photons. It was also found that the theoretical and the experimental values of present work and literature data for the 93 Nb(γ, xn) reaction cross-sections increase from the threshold values to a certain energy, where other reaction channels opens. However, the increase of 93 Nb(γ, n) and 93 Nb(γ, 2n) reaction cross-sections are sharper compared to 93 Nb(γ, 3n) and 93 Nb(γ, 4n) reaction cross-sections. The sharp increase of 93 Nb(γ, n) and 93 Nb(γ, 2n) reaction cross-sections from the threshold value up to 17–22 MeV is due to the Giant Dipole Resonance (GDR) effect besides the role of excitation energy. After a certain values, the individual 93 Nb(γ, xn) reaction cross-sections decrease with increase of bremsstrahlung energy due to opening of other reaction channels

77 FR 24762 - Mitsubishi Motors North America, Inc., Grant of Petition for Decision of Inconsequential...

Science.gov (United States)

2012-04-25

... instruction standards. Refer to Hyundai Motor Company (74 FR 9125, March 2, 209); Ford Motor Company (73 FR 11462, March 3, 2008); Mazda North America Operations (73 FR 11464, March 3, 2008); Ford Motor Company...-0176; Notice 2] Mitsubishi Motors North America, Inc., Grant of Petition for Decision of...

Computing the Fréchet distance between folded polygons

NARCIS (Netherlands)

Cook IV, A.F.; Driemel, A.; Sherette, J.; Wenk, C.

2015-01-01

Computing the Fréchet distance for surfaces is a surprisingly hard problem and the only known polynomial-time algorithm is limited to computing it between flat surfaces. We study the problem of computing the Fréchet distance for a class of non-flat surfaces called folded polygons. We present a

78 FR 71565 - Secretarial Infrastructure Business Development Mission to Mexico

Science.gov (United States)

2013-11-29

... DEPARTMENT OF COMMERCE Office of Business Liaison Secretarial Infrastructure Business Development... amending the Notice published at 78 FR 48855, August 12, 2013, regarding the Secretarial Infrastructure..., Trade Program Assistant. [FR Doc. 2013-28579 Filed 11-27-13; 8:45 am] BILLING CODE 3510-FP-P ...

75 FR 63181 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2010-10-14

... recordkeeping requirement for brokers and dealers to document the purpose of their loans secured by margin stock.... The purpose statements, FR U-1 and FR G-3, are recordkeeping requirements for brokers and dealers... FEDERAL RESERVE SYSTEM Proposed Agency Information Collection Activities; Comment Request AGENCY...

Evaluation methodology and prospective introduction scenarios of FR cycle systems

International Nuclear Information System (INIS)

Fujii, Sumio; Katoh, Atsushi; Sato, Kazujiro

2003-01-01

The 21st century society will be facing growing demand of energy, global environmental issues and concerns about fossil fuel exhaustion. In this society, it is essential to seek for a sustainable energy system to solve these energy-related concerns. In order to find ways for solving these problems, 'Feasibility Study on Commercialized FR Cycle System' was launched in 1999 as a joint research project of JNC, electric utilities, JAERI, CRIEPI etc. This project aims to build promising FR cycle technologies for the 21st century. Now, we are in the second phase (JFY 2001-2005) of this project. At the end of the second phase, we will propose promising concepts through applying innovative technologies. We started this Feasibility Study with defining the development target, which ended in five items; safety, economy, environmental burden, resource utilization and nuclear non-proliferation. These items should also serve as basic viewpoints to evaluate achievements of the study. This paper describes how we evaluate FR cycle options to come up with the final promising candidates. This paper also describes a prospective scenario to introduce FR cycle system, which shows how the FR cycle will be replacing existing LWRs by using limited natural uranium resource and spent fuels. (author)

75 FR 58305 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Revised Format for...

Science.gov (United States)

2010-09-24

... monoxide, Hydrocarbons, Incorporation by reference, Intergovernmental relations, Lead, Nitrogen dioxide... 60735 Sec. 6. 7/31/2009 11/20/2009, 74 FR 60197 Sec. 3. 1-2 Definitions 9/26/1980 11/5/1981, 46 FR 54943.../2009, 74 FR 52891.... Paragraph (c). and Marion Cos. 2009 Chicago Hydrocarbon Control Strategy..... 8...

General proof of the entropy principle for self-gravitating fluid in f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Fang, Xiongjun [Department of Physics and Key Laboratory of Low Dimensional Quantum Structures andQuantum Control of Ministry of Education, Hunan Normal University,Changsha, Hunan 410081 (China); Guo, Minyong [Department of Physics, Beijing Normal University,Beijing 100875 (China); Jing, Jiliang [Department of Physics and Key Laboratory of Low Dimensional Quantum Structures andQuantum Control of Ministry of Education, Hunan Normal University,Changsha, Hunan 410081 (China)

2016-08-29

The discussions on the connection between gravity and thermodynamics attract much attention recently. We consider a static self-gravitating perfect fluid system in f(R) gravity, which is an important theory could explain the accelerated expansion of the universe. We first show that the Tolman-Oppenheimer-Volkoff equation of f(R) theories can be obtained by thermodynamical method in spherical symmetric spacetime. Then we prove that the maximum entropy principle is also valid for f(R) gravity in general static spacetimes beyond spherical symmetry. The result shows that if the constraint equation is satisfied and the temperature of fluid obeys Tolmans law, the extrema of total entropy implies other components of gravitational equations. Conversely, if f(R) gravitational equation hold, the total entropy of the fluid should be extremum. Our work suggests a general and solid connection between f(R) gravity and thermodynamics.

75 FR 6151 - Chartering and Field of Membership for Federal Credit Unions

Science.gov (United States)

2010-02-08

... the terms ``rural district'' and ``in danger of insolvency'' for emergency merger purposes. 74 FR... the term ``in danger of insolvency'' for emergency merger purposes. 74 FR 68722 (December 29, 2009...

Robust approach to f(R) gravity

International Nuclear Information System (INIS)

Jaime, Luisa G.; Patino, Leonardo; Salgado, Marcelo

2011-01-01

We consider metric f(R) theories of gravity without mapping them to their scalar-tensor counterpart, but using the Ricci scalar itself as an ''extra'' degree of freedom. This approach avoids then the introduction of a scalar-field potential that might be ill defined (not single valued). In order to explicitly show the usefulness of this method, we focus on static and spherically symmetric spacetimes and deal with the recent controversy about the existence of extended relativistic objects in certain class of f(R) models.

77 FR 35021 - Kwan Bo Jin, M.D.; Decision and Order

Science.gov (United States)

2012-06-12

...] DEA registration is not appropriate.'' Anibal P. Herrera, M.D., 61 FR 65,075, 65,078 (DEA 1996); see... ``there were serious questions as to the integrity of the registrant.'' Anibal P. Herrera, M.D., 61 FR 65...

Galaxy-galaxy weak gravitational lensing in f(R) gravity

Science.gov (United States)

Li, Baojiu; Shirasaki, Masato

2018-03-01

We present an analysis of galaxy-galaxy weak gravitational lensing (GGL) in chameleon f(R) gravity - a leading candidate of non-standard gravity models. For the analysis, we have created mock galaxy catalogues based on dark matter haloes from two sets of numerical simulations, using a halo occupation distribution (HOD) prescription which allows a redshift dependence of galaxy number density. To make a fairer comparison between the f(R) and Λ cold dark matter (ΛCDM) models, their HOD parameters are tuned so that the galaxy two-point correlation functions in real space (and therefore the projected two-point correlation functions) match. While the f(R) model predicts an enhancement of the convergence power spectrum by up to ˜ 30 per cent compared to the standard ΛCDM model with the same parameters, the maximum enhancement of GGL is only half as large and less than 5 per cent on separations above ˜1-2 h-1 Mpc, because the latter is a cross-correlation of shear (or matter, which is more strongly affected by modified gravity) and galaxy (which is weakly affected given the good match between galaxy autocorrelations in the two models) fields. We also study the possibility of reconstructing the matter power spectrum by combination of GGL and galaxy clustering in f(R) gravity. We find that the galaxy-matter cross-correlation coefficient remains at unity down to ˜2-3 h-1 Mpc at relevant redshifts even in f(R) gravity, indicating joint analysis of GGL and galaxy clustering can be a powerful probe of matter density fluctuations in chameleon gravity. The scale dependence of the model differences in their predictions of GGL can potentially allows us to break the degeneracy between f(R) gravity and other cosmological parameters such as Ωm and σ8.

77 FR 67816 - Proposed Agency Information Collection Activities; Comment Request

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2012-11-14

... complements the triennial Survey of Foreign Exchange and Derivatives Market Activity (FR 3036; OMB No. 7100... Derivative Market Activity. Agency form number: FR 3036. OMB control number: 7100-0285. Frequency: One-time... derivatives market and dealers. Estimated annual reporting hours: Turnover Survey, 2,275 hours; Outstandings...

The holographic bound in the scalar-tensor and f(R) gravities

International Nuclear Information System (INIS)

Firouzjaee, J.T.

2013-01-01

The holographic bound has been extended to the different theory of gravities such as scalar-tensor gravity and f(R) gravity according to the Noether charge definition of the entropy for a black hole surface. We have introduced some popular examples of the flat FRW cosmology in order to investigate holographic bound in scalar-tensor and f(R) gravity. Using the holographic bound, we put an additional constraint on scalar-tensor gravity and the f(R) gravity parameters. We also discuss the transformation from Jordan frame to Einstein frame. (orig.)

Late-time cosmological approach in mimetic f(R, T) gravity

Energy Technology Data Exchange (ETDEWEB)

Baffou, E.H. [Institut de Mathematiques et de Sciences Physiques (IMSP), Porto-Novo (Benin); Houndjo, M.J.S. [Institut de Mathematiques et de Sciences Physiques (IMSP), Porto-Novo (Benin); Faculte des Sciences et Techniques de Natitingou, Natitingou (Benin); Hamani-Daouda, M. [Universite de Niamey, Departement de Physique, Niamey (Niger); Alvarenga, F.G. [Universidade Federal do Espirito Santo, Departamento de Engenharia e Ciencias Naturais, CEUNES, Sao Mateus, ES (Brazil)

2017-10-15

In this paper, we investigate the late-time cosmic acceleration in mimetic f(R, T) gravity with the Lagrange multiplier and potential in a Universe containing, besides radiation and dark energy, a self-interacting (collisional) matter. We obtain through the modified Friedmann equations the main equation that can describe the cosmological evolution. Then, with several models from Q(z) and the well-known particular model f(R, T), we perform an analysis of the late-time evolution. We examine the behavior of the Hubble parameter, the dark energy equation of state and the total effective equation of state and in each case we compare the resulting picture with the non-collisional matter (assumed as dust) and also with the collisional matter in mimetic f(R, T) gravity. The results obtained are in good agreement with the observational data and show that in the presence of the collisional matter the dark energy oscillations in mimetic f(R, T) gravity can be damped. (orig.)

Final feasibility study of possibilities and potentials of the disused iron ore mine Konrad (FRG) for low-level waste and decommissioning waste disposal

International Nuclear Information System (INIS)

Brewitz, W.; Stippler, R.

1982-01-01

The ''Institut fur Tieflagerung'' of the Gesellschaft fur Strahlen- and Umweltforschung, in collaboration with the Kernforschungszentrum Karlsruhe, carries out geoscientific and technical investigations in the disused iron ore mine Konrad. The aim is to prove the mine's feasibility for the disposal of low-level radioactive waste and decommissioning waste as well as the use of the existing mining installations. The investigations were initiated in 1975 and are being financed by the Minister for Research and Technology of the Federal Republic of Germany. Since 1978 the work is being supported as well by the Commission of the European Community in the scope of two years each. So far an amount of 60 mio DM has been spent, 86% for maintenance and further operation of the mine and 14% for research work

76 FR 65653 - New Source Performance Standards (NSPS) Review

Science.gov (United States)

2011-10-24

... current within their review cycle, there are also multiple standards in different phases of the review... Rock Plants NN 04/16/1982 (47FR16589) 10/17/2000 3 4 (65FR61760) Polymeric Coating of Supporting VVV 09... whether review of a particular NSPS is necessary during the review cycle. A listing of any NSPS for which...

78 FR 17108 - Approval and Promulgation of Implementation Plans; State of Washington; Revised Format for...

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2013-03-20

...), EPA revised the procedures for IBR'ing Federally-approved SIPs, as a result of consultations between... Violations--Notices 9/8/93 2/22/95, 60 FR 9778 132 Criminal Penalty 11/13/94 10/24/95, 60 FR 54439 133 Civil............ Regulatory Actions & Civil 9/21/95 2/26/97, 62 FR 8624......... Penalties. 400-240......... Criminal...

78 FR 61348 - Environmental Management Site-Specific Advisory Board, Portsmouth

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2013-10-03

...On September 16, 2013, in FR Doc. 2013-22453, on page 56871, the Department of Energy (DOE) published a notice of open meeting announcing a meeting on October 2, 2013 of the Environmental Management Site-Specific Advisory Board, Portsmouth (78 FR 56871). This notice announces the cancellation of this meeting.

78 FR 38976 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2013-06-28

...)). Abstract: The Federal Reserve proposes to implement the mandatory Report of Selected Money Market Rates (FR... used in the analysis of current money market conditions. The FR 2420 would collect data for three.... Excluded from Eurodollar transactions are: Demand deposits (as defined on the Schedule E of the Call Report...

77 FR 26777 - Endangered Species; Marine Mammals; Issuance of Permits

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2012-05-07

... not operate to the disadvantage of the endangered species, and (3) The granted permit would be..., 2012. 64654A Double Springs 77 FR 6816; March 14, 2012. Partnership Ltd. February 9, 2012. 64656A Double Springs 77 FR 6816; March 14, 2012. Partnership Ltd. February 9, 2012. 64723A Larry Friesenhahn...

75 FR 47797 - Privacy Act of 1974; System of Records

Science.gov (United States)

2010-08-09

... Officer, Department of Defense. Deletion: S330.40 CAHS System name: Employee Assistance Program Records (August 27, 1999; 64 FR 46889). Reason: This collection is covered under the existing DHHS/FOH EAP Privacy notice 09-90-0010, entitled ``Employee Assistance Program (EAP) Records, HHS/OS/ASAM/OHR.'' [FR Doc. 2010...

f(R) constant-roll inflation

Energy Technology Data Exchange (ETDEWEB)

Motohashi, Hayato [Universidad de Valencia-CSIC, Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Starobinsky, Alexei A. [L.D. Landau Institute for Theoretical Physics, RAS, Moscow (Russian Federation); National Research University Higher School of Economics, Moscow (Russian Federation)

2017-08-15

The previously introduced class of two-parametric phenomenological inflationary models in general relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of f(R) gravity. A simple constant-roll condition is defined in the original Jordan frame, and exact expressions for a scalaron potential in the Einstein frame, for a function f(R) (in the parametric form) and for inflationary dynamics are obtained. The region of the model parameters permitted by the latest observational constraints on the scalar spectral index and the tensor-to-scalar ratio of primordial metric perturbations generated during inflation is determined. (orig.)

76 FR 69333 - Derivatives Clearing Organization General Provisions and Core Principles

Science.gov (United States)

2011-11-08

... Management)); 75 FR 78185 (Dec. 15, 2010) (Core Principles J, K, L, and M (Information Management)); 75 FR... Parts 1, 21, 39 et al. Derivatives Clearing Organization General Provisions and Core Principles; Final... Derivatives Clearing Organization General Provisions and Core Principles AGENCY: Commodity Futures Trading...

F(R Gravity’s Rainbow and Its Einstein Counterpart

Directory of Open Access Journals (Sweden)

S. H. Hendi

2016-01-01

Full Text Available Motivated by UV completion of general relativity with a modification of a geometry at high energy scale, it is expected to have an energy dependent geometry. In this paper, we introduce charged black hole solutions with power Maxwell invariant source in the context of gravity’s rainbow. In addition, we investigate two classes of F(R gravity’s rainbow solutions. At first, we study energy dependent F(R gravity without energy-momentum tensor, and then we obtain F(R gravity’s rainbow in the presence of conformally invariant Maxwell source. We study geometrical properties of the mentioned solutions and compare their results. We also give some related comments regarding thermodynamical behavior of the obtained solutions and discuss thermal stability of the solutions.

Cosmology of Horava-Lifshitz f(R) gravity

International Nuclear Information System (INIS)

Chakrabarti, Sayan K.; Sen, Anjan A.

2011-08-01

We discuss the cosmology of recently proposed Horava-Lifshitz f(R) gravity. In particular, we derive the modified Hubble equation that reduces to the standard HL gravity case in appropriate limit. We show how the bounce solutions in this theory are modified due to nonlinear effect of f(R) gravity. In addition we find that the solutions exist when the Universe can make turn around for large scale-factor. Therefore, in principle, the Universe in this set-up can show cyclic behavior. (orig.)

Cosmology of Horava-Lifshitz f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Chakrabarti, Sayan K. [Univ. Tecnica de Lisboa (Portugal). Inst. Superior Tecnico; Dutta, Koushik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sen, Anjan A. [Centre of Theoretical Physics, Jamia Millia Islamia, New Dehli (India)

2011-08-15

We discuss the cosmology of recently proposed Horava-Lifshitz f(R) gravity. In particular, we derive the modified Hubble equation that reduces to the standard HL gravity case in appropriate limit. We show how the bounce solutions in this theory are modified due to nonlinear effect of f(R) gravity. In addition we find that the solutions exist when the Universe can make turn around for large scale-factor. Therefore, in principle, the Universe in this set-up can show cyclic behavior. (orig.)

75 FR 81349 - Change to the Reporting Date for Certain Data Elements Required Under the Mandatory Reporting of...

Science.gov (United States)

2010-12-27

... facilities. Ammonia Manufacturing 325311 Anhydrous and aqueous ammonia manufacturing facilities. Cement Production 327310 Portland Cement manufacturing plants. Electronics Manufacturing 334111 Microcomputers.... Ammonia Manufacturing......... G 74 FR 56260, Revised 11-24- 2010. Cement Production H 74 FR 56260, 75 FR...

Constraining f(R gravity in solar system, cosmology and binary pulsar systems

Directory of Open Access Journals (Sweden)

Tan Liu

2018-02-01

Full Text Available The f(R gravity can be cast into the form of a scalar–tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general f(R gravity, using a scalar–tensor representation with the chameleon mechanism, we calculate the parametrized post-Newtonian parameters γ and β, the effective gravitational constant Geff, and the effective cosmological constant Λeff. In addition, for the general f(R gravity, we also calculate the rate of orbital period decay of the binary system due to gravitational radiation. Then we apply these results to specific f(R models (Hu–Sawicki model, Tsujikawa model and Starobinsky model and derive the constraints on the model parameters by combining the observations in solar system, cosmological scales and the binary systems.

Existence of relativistic stars in f(R) gravity

International Nuclear Information System (INIS)

Upadhye, Amol; Hu, Wayne

2009-01-01

We refute recent claims in the literature that stars with relativistically deep potentials cannot exist in f(R) gravity. Numerical examples of stable stars, including relativistic (GM * /r * ∼0.1), constant density stars, are studied. As a star is made larger, nonlinear 'chameleon' effects screen much of the star's mass, stabilizing gravity at the stellar center. Furthermore, we show that the onset of this chameleon screening is unrelated to strong gravity. At large central pressures P>ρ/3, f(R) gravity, like general relativity, does have a maximum gravitational potential, but at a slightly smaller value: GM * /r * | max =0.345<4/9 for constant density and one choice of parameters. This difference is associated with negative central curvature R under general relativity not being accessed in the f(R) model, but does not apply to any known astrophysical object.

A viable logarithmic f(R) model for inflation

Energy Technology Data Exchange (ETDEWEB)

Amin, M.; Khalil, S. [Center for Fundamental Physics, Zewail City of Science and Technology,6 October City, Giza (Egypt); Salah, M. [Center for Fundamental Physics, Zewail City of Science and Technology,6 October City, Giza (Egypt); Department of Mathematics, Faculty of Science, Cairo University,Giza (Egypt)

2016-08-18

Inflation in the framework of f(R) modified gravity is revisited. We study the conditions that f(R) should satisfy in order to lead to a viable inflationary model in the original form and in the Einstein frame. Based on these criteria we propose a new logarithmic model as a potential candidate for f(R) theories aiming to describe inflation consistent with observations from Planck satellite (2015). The model predicts scalar spectral index 0.9615

Closed string tachyon driving f(R) cosmology

Science.gov (United States)

Wang, Peng; Wu, Houwen; Yang, Haitang

2018-05-01

To study quantum effects on the bulk tachyon dynamics, we replace R with f(R) in the low-energy effective action that couples gravity, the dilaton, and the bulk closed string tachyon of bosonic closed string theory and study properties of their classical solutions. The α' corrections of the graviton-dilaton-tachyon system are implemented in the f(R). We obtain the tachyon-induced rolling solutions and show that the string metric does not need to remain fixed in some cases. In the case with H( t=‑∞ ) = , only the R and R2 terms in f(R) play a role in obtaining the rolling solutions with nontrivial metric. The singular behavior of more classical solutions are investigated and found to be modified by quantum effects. In particular, there could exist some classical solutions, in which the tachyon field rolls down from a maximum of the tachyon potential while the dilaton expectation value is always bounded from above during the rolling process.

77 FR 8002 - Unified Agenda of Federal Regulatory and Deregulatory Actions

Science.gov (United States)

2012-02-13

... include requirements for public rights-of-way. Timetable: Action Date FR Cite Notice of Intent to Form...) Accessibility Guidelines for Buildings and Facilities: Public Rights- of-Way. ARCHITECTURAL AND TRANSPORTATION... ferries, excursion boats, and other passenger vessels. Timetable: Action Date FR Cite Notice of Intent to...

Fr Luigi Giussani’s Concept of Education - an Outline

Directory of Open Access Journals (Sweden)

Alina Rynio

2011-09-01

Full Text Available This outline focuses on the multifarious academic, pedagogical and social activities of Fr Luigi Giussani, Professor of Theology, Italian thinker and scholar renowned for his numerous accomplishments. Due to his exceptional attentiveness, inquisitiveness and courage he has been certainly well-known and highly-regarded not only in university and ecclesiastical but also in the cultural and political spheres of life. The author of this study describes Fr Giussani as an exceptional scholar and educator emphasising the pedagogical aspect of his activities. The study explains his understanding of pedagogy and education. Selected achievements from his biography con fi rm Fr Giussani to be an exceptional human being, educator and scholar. As an educator, Fr Giussani holds a sober and realistic view of man and his formation: the true value of man, he claims, lies in being rational and free. Complete trust in God and great love for a human person de fi ne the most fundamental elements of his approach. The outline also includes a short biographical note and describes popular ways of education, formative events, the educators and educatee’s personality constituents, and the relationship between freedom, conscience, tradition and education.

76 FR 73604 - Privacy Act of 1974; System of Records

Science.gov (United States)

2011-11-29

... Defense. Deletion: K890.12 Identity Management (IDM) (March 18, 2010, 75 FR 13090). Reason: Due to policy... (SAAM) project (formerly known as Identity Management). [FR Doc. 2011-30698 Filed 11-28-11; 8:45 am... Docket Management System Office, 4800 Mark Center Drive, East Tower, 2nd floor, Suite 02G09, Alexandria...

Distinguishing f(R) theories from general relativity by gravitational lensing effect

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongguang [Beijing Normal University, Department of Physics, Beijing (China); Aix Marseille Universite et Universite de Toulon, Centre de Physique Theorique (UMR 7332), Marseille (France); Wang, Xin; Li, Haida; Ma, Yongge [Beijing Normal University, Department of Physics, Beijing (China)

2017-11-15

The post-Newtonian formulation of a general class of f(R) theories is set up in a third-order approximation. It turns out that the information of a specific form of f(R) gravity is encoded in the Yukawa potential, which is contained in the perturbative expansion of the metric components. Although the Yukawa potential is canceled in the second-order expression of the effective refraction index of light, detailed analysis shows that the difference of the lensing effect between the f(R) gravity and general relativity does appear at the third order when √(f''(0)/f{sup '}(0)) is larger than the distance d{sub 0} to the gravitational source. However, the difference between these two kinds of theories will disappear in the axially symmetric spacetime region. Therefore only in very rare case the f(R) theories are distinguishable from general relativity by gravitational lensing effect in a third-order post-Newtonian approximation. (orig.)

Forty-Fourth Meeting of the Technical Working Group on Fast Reactors (TWG-FR). Working Material

International Nuclear Information System (INIS)

2011-01-01

The objectives of the meeting were to: - Exchange information on the national programmes on Fast Reactors (FR) and Accelerator Driven Systems (ADS); - Review the progress since the 43rd TWG-FR Annual Meeting, including the status of the actions; - Consider topical technical meeting arrangements for 2012-2013, as well as review FR-related activities included in the IAEA Project&Budget (P&B) biennium 2012-2013; - Review the IAEA’s ongoing information exchange and coordinated research projects in the technical fields relevant to the TWG-FR (FRs and ADS), as well as coordination of the TWG-FR’s activities with other organizations and international initiatives (GIF, INPRO, NEA, ESNII, etc.)

Promising fast reactor systems in the feasibility study on commercialized FR cycle system

International Nuclear Information System (INIS)

Sakamoto, Y.; Kotake, S.; Enuma, Y.; Sagayama, Y.; Nishikawa, A.; Ando, M.

2005-01-01

The Feasibility Study on Commercialized Fast Reactor (FR) Cycle Systems is under way in order to propose prominent FR cycle systems that will respond to the diverse needs of society in the future. The design studies on various FR system concepts have been achieved and then the evaluations of potential to achieve the development targets have been carried out. Crucial issues have been found out for each FR system concept and their development plans for the key technologies are summarized as the roadmap. The characteristics and the differences in performances have been investigated. The crucial issues and the development periods have been clarified. Further investigation is now in progress. The promising concept will be proposed based on result of comparative evaluation at the end of the Phase II study. (authors)

Research of the cost-benefit analysis for FR cycle research and development. The annual report of the FY 2001

International Nuclear Information System (INIS)

Shiotani, Hiroki; Shinoda, Yoshihiko; Hirao, Kazunori

2002-07-01

This report is intended to explain the outline of the research and development (R and D) in the FY 2001 on cost-benefit analysis of FR (Fast Reactor) cycle system concepts. The work was conducted as a part of the JNC's Feasibility Study on Commercialized Fast Reactor Cycle Systems (the F/S)'. In the FY 2001, the work conducted in the JNC was summed up as the followings: Conceptual study on cost-benefit analysis for FR cycle R and D. Refinement on the evaluation procedure and improvement over operation efficiency. Cost-benefit analysis of the reference FR cycle and sensitivity analysis with the revised system. Cost-benefit analyses of R and Ds for various FR cycle candidate concepts including FR cycle concepts studied in the F/S phase 1. The work made it possible to evaluate the cost effectiveness of various FR cycle systems efficiently. The cost-benefit analysis, which is often used for the policy evaluation, is considered to be applicable to FR cycle system concepts in the F/S. (author)

Shopping Mall: Konsumtempel oder neuer ‚Frauenraum‘ im Zentrum der Stadt?

Directory of Open Access Journals (Sweden)

Stephanie Bock

2008-11-01

Full Text Available Die in den USA entstandene Shopping Mall ist aus den europäischen Stadtzentren nicht mehr wegzudenken. Kerstin Dörhöfer geht in ihrem Buch an ausgewählten Berliner Beispielen der Frage nach der Wirkung dieser vermeintlich homogenen baulichen ‚Monolithen‘ auf urbane Kultur und vor allem auf die Geschlechterverhältnisse nach. Die allmähliche Eroberung der Innenstädte durch die Shopping Mall ist – so das Fazit der lesenswerten Arbeit – kein Ausdruck einer verstärkten Teilhabe von Frauen am städtischen Leben. Vielmehr konterkariert der neue Innenraum im öffentlichen Stadtraum die mit Urbanität verbundene Vorstellung einer Aneignung städtischen Raums.

A no-hair theorem for black holes in f(R) gravity

Science.gov (United States)

Cañate, Pedro

2018-01-01

In this work we present a no-hair theorem which discards the existence of four-dimensional asymptotically flat, static and spherically symmetric or stationary axisymmetric, non-trivial black holes in the frame of f(R) gravity under metric formalism. Here we show that our no-hair theorem also can discard asymptotic de Sitter stationary and axisymmetric non-trivial black holes. The novelty is that this no-hair theorem is built without resorting to known mapping between f(R) gravity and scalar–tensor theory. Thus, an advantage will be that our no-hair theorem applies as well to metric f(R) models that cannot be mapped to scalar–tensor theory.

Numerical study on the selective excitation of Helmholtz-Gauss beams in end-pumped solid-state digital lasers with the control of the laser gain transverse position provided by off-axis end pumping

Science.gov (United States)

Tsai, Ko-Fan; Chu, Shu-Chun

2018-03-01

This study proposes a complete and unified method for selective excitation of any specified nearly nondiffracting Helmholtz-Gauss (HzG) beam in end-pumped solid-state digital lasers. Four types of the HzG beams: cosine-Gauss beams, Bessel-Gauss beams, Mathieu-Gauss beams, and, in particular, parabolic-Gauss beams are successfully demonstrated to be generated with the proposed methods. To the best of the authors’ knowledge, parabolic-Gauss beams have not yet been directly generated from any kind of laser system. The numerical results of this study show that one can successfully achieve any lasing HzG beams directly from the solid-state digital lasers with only added control of the laser gain transverse position provided by off-axis end pumping. This study also presents a practical digital laser set-up for easily manipulating off-axis pumping in order to achieve the control of the laser gain transverse gain position in digital lasers. The reported results in this study provide advancement of digital lasers in dynamically generating nondiffracting beams. The control of the digital laser cavity gain position creates the possibility of achieving real-time selection of more laser modes in digital lasers, and it is worth further investigation in the future.

78 FR 27153 - Duty Periods for Establishing Eligibility for Health Care

Science.gov (United States)

2013-05-09

.... Quartermaster Corps Female Recognized 46 FR 11857. Clerical Employees serving with effective January the.... civilian female employees Recognized 59 FR 298. of the U.S. Army Nurse Corps effective while serving in the.... civilian female employees of the U.S. Army Nurse Corps while serving in the Defense of Bataan and...

77 FR 68149 - Karen Paul Holley, M.D.; Decision and Order

Science.gov (United States)

2012-11-15

... DEPARTMENT OF JUSTICE Drug Enforcement Administration [Docket No. 12-51] Karen Paul Holley, M.D... revoke the DEA Certificate of Registration (COR), Number BH8988339, of Karen Paul Holley, M.D....D., 74 FR 17528, 174529 (2009); John B. Freitas, D.O., 74 FR 17524, 17525 (2009); Roger A. Rodriguez...

Forty-Fifth Annual Meeting of the Technical Working Group on Fast Reactors (TWG-FR). Working Material

International Nuclear Information System (INIS)

2012-01-01

The objectives of the meeting were to: • Exchange information on the national programmes on Fast Reactors (FR) and Accelerator Driven Systems (ADS); • Review the progress since the 44 th TWG-FR Annual Meeting, including the status of the actions; • Consider topical technical meeting arrangements for 2012-2013, as well as review FR-related activities included in the IAEA Programme & Budget (P&B) biennium 2012-2013; • Review the IAEA’s concluded, on-going and planned coordinated research projects in the technical fields relevant to the TWG-FR (FRs and ADS), as well as coordination of the TWG-FR’s activities with other organizations and international initiatives (GIF, INPRO, NEA, ESNII, etc.). The 45th Meeting of the TWG-FR reached the following conclusions/recommendations: • The participants expressed satisfaction and appreciation for the large amount of new information on on-going activities carried out by the Member States in the field of FR and ADS exchanged during the meeting; • Also the organizations which have participated to the TWG-FR meeting for the first time expressed their appreciation for the lively discussion and the results and thanked the IAEA for inviting them at the meeting; • The meeting was very useful in particular for collecting inputs and advice in view of the preparation of the IAEA Programme & Budget 2014-2015 (and then 2016-2017) in the area of FR and ADS technology development; • The TWG-FR remains an unique international forum for information exchange in the field of fast neutron systems and for promoting RT&D activities in this area; • Due to the increasing interest in FR and in view of the forthcoming realizations, it would be advisable to increase the involvement of industries, regulators and other R&D organizations; • The annual TWG-FR meeting should focused on exchange of information on national and international programmes, avoiding duplications or overlapping’s with other IAEA initiatives in the field; �

Validation and Verification (V and V) Testing on Midscale Flame Resistant (FR) Test Method

Science.gov (United States)

2016-12-16

materials . The results demonstrated that the Midscale test is a quick and cost-effective method for evaluation of FR performance of design features...standard and novel FR materials and design configurations during fire engulfment. Details of the test method and its development can be found in the...employed in the FRACU is a ripstop fabric blend of 65% FR rayon, 25% para- aramid and 10% nylon. The iCVC material is Nylon/Cotton/Nomex. All three

78 FR 64204 - Science and Technology Reinvention Laboratory Personnel Management Demonstration Project...

Science.gov (United States)

2013-10-28

... Personnel Management Demonstration Project, Department of Navy, Office of Naval Research (ONR); Amendment... ONR Personnel Management Demonstration Project (75 FR 77380-77447, December 10, 2010). SUMMARY: On December 10, 2010 (75 FR 77380-77447), DoD published a notice of approval of a personnel management...

78 FR 55225 - Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine Particle Standard...

Science.gov (United States)

2013-09-10

...); and 75 FR 27944 (May 19, 2010) (Coso Junction, California area). Thus EPA has established that, under... Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993); Does not... based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997); Is not a...

Disentangling the f(R). Duality

International Nuclear Information System (INIS)

Broy, Benedict J.; Westphal, Alexander; Pedro, Francisco G.; Univ. Autonoma de Madrid

2014-11-01

Motivated by UV realisations of Starobinsky-like inflation models, we study generic exponential plateau-like potentials to understand whether an exact f(R)-formulation may still be obtained when the asymptotic shift-symmetry of the potential is broken for larger field values. Potentials which break the shift symmetry with rising exponentials at large field values only allow for corresponding f(R)-descriptions with a leading order term R n with 1 2 -term survives as part of a series expansion of the function f(R) and thus cannot maintain a plateau for all field values. We further find a lean and instructive way to obtain a function f(R) describing m 2 φ 2 -inflation which breaks the shift symmetry with a monomial, and corresponds to effectively logarithmic corrections to an R+R 2 model. These examples emphasise that higher order terms in f(R)-theory may not be neglected if they are present at all. Additionally, we relate the function f(R) corresponding to chaotic inflation to a more general Jordan frame set-up. In addition, we consider f(R)-duals of two given UV examples, both from supergravity and string theory. Finally, we outline the CMB phenomenology of these models which show effects of power suppression at low-l.

On the 221 Rn → 221 Fr decay scheme

International Nuclear Information System (INIS)

Gromov, K.Ya.; Norseev, Yu.V.; Samatov, Zh.K.; Fominykh, V.I.; Chumin, V.G.; Kudrya, S.A.; Sergienko, V.A.

2002-01-01

The results of investigating the 221 Rnβ - - decay and the 225 Ac α-decay are compared. It is shown that 221 Fr levels at 145.9 and 393.2 keV are excited at the 221 Rn decay. Intensities and reduced probabilities of the β - - decay to the 221 Fr levels are determined. A conclusion is drawn that the parity of the 221 Rn ground state is positive

Forty-Fifth Annual Meeting of the Technical Working Group on Fast Reactors (TWG-FR). Presentations

International Nuclear Information System (INIS)

2012-01-01

The objectives of the meeting were to: • Exchange information on the national programmes on Fast Reactors (FR) and Accelerator Driven Systems (ADS); • Review the progress since the 44 th TWG-FR Annual Meeting, including the status of the actions; • Consider topical technical meeting arrangements for 2012-2013, as well as review FR-related activities included in the IAEA Programme & Budget (P&B) biennium 2012-2013; • Review the IAEA’s concluded, on-going and planned coordinated research projects in the technical fields relevant to the TWG-FR (FRs and ADS), as well as coordination of the TWG-FR’s activities with other organizations and international initiatives (GIF, INPRO, NEA, ESNII, etc.)

Reconstructing an f(R) model from holographic dark energy: using the observational evidence

International Nuclear Information System (INIS)

Saaidi, Kh; Aghamohammadi, A

2012-01-01

We investigate the correspondence relation between f(R) gravity and an interacting holographic dark energy (HDE). By obtaining the conditions needed for some observational evidence such as positive acceleration expansion of the Universe, crossing the phantom divide line and validity of the thermodynamics second law in an interacting HDE model and corresponding it with the f(R) model of gravity, we find a viable f(R) model that can explain the present Universe. We also obtain the explicit evolutionary forms of the corresponding scalar field, potential and scale factor of the Universe. (paper)

76 FR 36879 - Minnesota: Final Authorization of State Hazardous Waste Management Program Revision

Science.gov (United States)

2011-06-23

... Treatment Subcategories for Radioactively Contaminated Cadmium-, Mercury-, and Silver- Containing Batteries..., 1998 (63 FR 28556) Land Disposal Restrictions Phase IV; Hazardous Soils Treatment Standards and..., October 22, 1998 (63 FR 56710) Hazardous Remediation Waste Management Requirements (HWIR-Media), Checklist...

LOW-POWER RADIO GALAXIES IN THE DISTANT UNIVERSE: A SEARCH FOR FR I AT 1 < z < 2 IN THE COSMOS FIELD

International Nuclear Information System (INIS)

Chiaberge, Marco; Tremblay, Grant; Macchetto, F. Duccio; Sparks, W. B.; Capetti, Alessandro; Tozzi, Paolo

2009-01-01

We present a search for FR I radio galaxies between 1 < z < 2 in the COSMOS field. In absence of spectroscopic redshift measurements, the selection method is based on multiple steps which make use of both radio and optical constraints. The basic assumptions are that (1) the break in radio power between low-power FR Is and the more powerful FR IIs does not change with redshift, and (2) that the photometric properties of the host galaxies of low-power radio galaxies in the distant universe are similar to those of FR IIs in the same redshift bin, as is the case for nearby radio galaxies. We describe the results of our search, which yields 37 low-power radio galaxy candidates that are possibly FR Is. We show that a large fraction of these low-luminosity radio galaxies display a compact radio morphology that does not correspond to the FR I morphological classification. Furthermore, our objects are apparently associated with galaxies that show clear signs of interactions, at odds with the typical behavior observed in low-z FR I hosts. The compact radio morphology might imply that we are observing intrinsically small and possibly young objects that will eventually evolve into the giant FR Is we observe in the local universe. One of the objects appears as pointlike in Hubble Space Telescope (HST) images. This might belong to a population of FR I-QSOs, which however would represent a tiny minority of the overall population of high-z FR Is. As for the local FR Is, a large fraction of our objects are likely to be associated with groups or clusters, making them 'beacons' for high-redshift clusters of galaxies. Our search for candidate high-z FR Is we present in this paper constitutes a pilot study for objects to be observed with future high-resolution and high-sensitivity instruments such as the EVLA and ALMA in the radio band, HST/WFC3 in the optical and IR, James Webb Space Telescope in the IR, as well as future generation X-ray satellites.

Euro-Islam or Islam in Europe: The Role of Muslims and Their Organizations in Germany, Great Britain and the Netherlands

Science.gov (United States)

2011-06-01

Netherlands (Islamitische Stichting Nederland , ISN) ....................................................126 b. The Foundation of the Turkish Islamic...Islamic Schools Government Board Organization ISC Islamic Sharia Council ISN Islamitisch Stichting Nederland (Islamic Foundation Netherlands) IZH...Islamisches Zentrum Hamburg (Islamic Center Hamburg) KMAN Kommitee van Maroccaanse Arbeiders in Nederland (Committee of Moroccan Workers in the

The effect of corazonin on heartbeat reversal in pupae of the tobacco hornworm, Manduca sexta (Lepidoptera: Sphingidae)

Czech Academy of Sciences Publication Activity Database

Sláma, Karel

2004-01-01

Roč. 101, č. 4 (2004), s. 513-521 ISSN 1210-5759 Grant - others:Deutsches Zentrum fur Luft- und Raumfahrt(DE) TSR-0720-97 Institutional research plan: CEZ:AV0Z5007907 Keywords : Heartbeat reversal * anterograde heartbeat * retrograde heartbeat, Subject RIV: ED - Physiology Impact factor: 0.657, year: 2004

Annual report 1976

International Nuclear Information System (INIS)

Godt, K.J.

1977-07-01

The paper gives a survey of R + D work in 1976 of the Institut fuer Strahlenschutz of the Gesellschaft fuer Strahlen- und Umweltforschung in Munich. The work, which has been carried out with practical application in mind, deals mainly with fundamental aspects of radiation protection, radiation physics and neutron dosimetry, applied radiation protection, analytics and ecology of radionuclides, and internal radiation exposure. The report presents results from current investigations, e.g. tumour diagnosis with the aid of automatic image processing (TUDAB), acquisition of cell data, microsdosimetry, establishment and updating of data banks in the framework of personnel dosimetry monitoring, determination by spectrometry of a sources in environmental samples and nuclear power plant emissions with the aid of large grid ionisation chambers, and local aerosol deposition in the respiratory tract. Advanced training courses in radiation protection are still held. (ORU) [de

Isotope hydrology

International Nuclear Information System (INIS)

Drost, W.

1978-01-01

The International Symposium on Isotope Hydrology was jointly organized by the IAEA and UNESCO, in co-operation with the National Committee of the Federal Republic of Germany for the International Hydrological Programme (IHP) and the Gesellschaft fuer Strahlen- und Umweltforschung mbH (GSF). Upon the invitation of the Federal Republic of Germany the Symposium was held from 19-23 June 1978 in Neuherberg on the GSF campus. The Symposium was officially opened by Mr. S. Eklund, Director General of the IAEA. The symposium - the fifth meeting held on isotope hydrology - was attended by over 160 participants from 44 countries and four international organizations and by about 30 observers from the Federal Republic of Germany. Due to the absence of scientists from the USSR five papers were cancelled and therefore only 46 papers of the original programme were presented in ten sessions

Purification of antilisterial peptide (SubtilosinA from novel Bacillus tequilensis FR9 and demonstrate their pathogen invasion protection ability using human carcinoma cell line.

Directory of Open Access Journals (Sweden)

Rizwana Parveen Rani

2016-12-01

Full Text Available This study focuses on isolation, screening and characterization of novel probiotics from gastrointestinal tract of free-range chicken (Gallus gallus domesticus. Fifty seven colonies were isolated and three isolates (FR4, FR9 and FR12 were selected and identified as Lactobacillus gasseri FR4, Bacillus tequilensis FR9 and L. animalis FR12 by 16S rRNA sequencing. Three strains were able to survive in stimulated acidic and bile conditions and inhibit the growth of pathogens. Especially, FR9 exhibited maximum inhibition against Listeria monocytogenes and none of them exhibited hemolytic activity. Native-PAGE revealed the presence of low molecular weight (3.4-5.0 KDa antimicrobial peptide. The peptide was further purified by Sephadex G-50 column and RP-HPLC using C18 column. N-terminal amino acid sequencing of antimicrobial peptide showed 100% consensus to antilisterial peptide SubtilosinA and SboA gene was amplified from FR9 genome. FR9 showed maximum aggregation activity, EPS production (85.46 mg/L and cholesterol assimilation (63.12 ± 0.05 µg/mL. Strong adhesion property (12.6% and pathogen invasion protection ability was revealed by B. tequilensis FR9 towards HCT-116 human colon carcinoma cell line. This is the first study to demonstrate antilisterial SubtilosinA production of B. tequilensis. Our results indicate that B. tequilensis FR9 strain furnish the essential characteristics of a potential probiotics and might be incorporated into human and animal food supplements.

Japanese FR Deployment Scenario Study after the Fukushima Accident

International Nuclear Information System (INIS)

Ono, Kiyoshi; Shiotani, Hiroki; Ohtaki, Akira; Mukaida, Kyoko; Abe, Tomoyuki

2013-01-01

Conclusion: • The results revealed a need for the implementation of reprocessing and development of FR from the view point of reducing waste, etc. in the medium to long term. • JAEA’s contribution to international cooperation and standardization focusing on the enhancement of safety and reduction of the radioactive waste burden will be increasingly important in current situation. • JAEA intend to continue to build and propose FR deployment scenarios and identify their characteristics

77 FR 15966 - Ohio: Final Authorization of State Hazardous Waste Management Program Revision

Science.gov (United States)

2012-03-19

... Hazardous Waste Management Program Revision AGENCY: Environmental Protection Agency (EPA). ACTION: Final..., 1989 (54 FR 27170) to implement the RCRA hazardous waste management program. We granted authorization... Combustors; Final Rule, Checklist 198, February 14, 2002 (67 FR 6968); Hazardous Waste Management System...

78 FR 17140 - Upholstered Furniture Fire Safety Technology; Meeting and Request for Comments

Science.gov (United States)

2013-03-20

... retardant (FR) chemicals, specialty fibers/fabrics without FR chemicals, inherently fire resistant materials... Furniture Fire Safety Technology; Meeting and Request for Comments AGENCY: Consumer Product Safety... Commission (CPSC, Commission, or we) is announcing its intent to hold a meeting on upholstered furniture fire...

Unifying inflation with dark energy in modified F(R) Horava-Lifshitz gravity

International Nuclear Information System (INIS)

Elizalde, E.; Saez-Gomez, D.; Nojiri, S.; Odintsov, S.D.

2010-01-01

We study FRW cosmology for a non-linear modified F(R) Horava-Lifshitz gravity which has a viable convenient counterpart. A unified description of early-time inflation and late-time acceleration is possible in this theory, but the cosmological dynamic details are generically different from the ones of the convenient viable F(R) model. Remarkably, for some specific choice of parameters they do coincide. The emergence of finite-time future singularities is investigated in detail. It is shown that these singularities can be cured by adding an extra, higher-derivative term, which turns out to be qualitatively different when compared with the corresponding one of the convenient F(R) theory. (orig.)

Propagating Degrees of Freedom in f(R Gravity

Directory of Open Access Journals (Sweden)

Yun Soo Myung

2016-01-01

Full Text Available We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in f(R gravity. These are three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor in f(R gravity satisfies the transverse-traceless (TT condition as well as the TT wave equation.

The coincidence problem in holographic f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Bisabr, Yousef, E-mail: y-bisabr@srttu.edu [Department of Physics, Shahid Rajaee Teacher Training University, Lavizan, Tehran 16788 (Iran, Islamic Republic of)

2011-09-15

It is well known that f(R) gravity models formulated in the Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. In this case, the scalar field couples with the matter sector and the coupling term is given by the conformal factor. We apply the holographic principle to such interacting models. In a spatially flat universe, we show that the Einstein frame representation of f(R) models leads to a constant ratio of energy densities of dark matter to dark energy.

Phage FR38 Treatment on Sprague Dawley Rat Inferred from Blood Parameters and Organ Systems

Directory of Open Access Journals (Sweden)

DEWI SARTIKA

2012-09-01

Full Text Available The ability of phage FR38 to lysis indigenous Salmonella P38 from feces of diarrheal patient has been studied. However, effects of phage FR38 on organ system were not revealed as yet. This study was conducted to observe the effect of phage FR38 on blood chemistry, kidney functions, and liver functions. Twelve Sprague-Dawley rats were used as a model for this study that were divided into two groups; (i control and (ii treated group with phage FR38. For treated phage group, each rat was administered by 5 ml/kg bw of 1.59•107 pfu/ml of phage intragastric. The blood parameters were analysed on day 16. The results revealed that body and organs weight, erythrocyte, hematocrit, hemoglobin, leukocyte, total protein, creatinine, SGOT, and SGPT of phage treatment rats were not significantly different with the control rats on day 16 (P > 0.05. Therefore, this study showed was no effect of phage FR38 on body weight, blood chemistry, kidney and liver functions of the rat (P > 0.05.

Phage FR38 Treatment on Sprague Dawley Rat Inferred from Blood Parameters and Organ Systems

Directory of Open Access Journals (Sweden)

DEWI SARTIKA

2012-09-01

Full Text Available The ability of phage FR38 to lysis indigenous Salmonella P38 from feces of diarrheal patient has been studied. However, effects of phage FR38 on organ system were not revealed as yet. This study was conducted to observe the effect of phage FR38 on blood chemistry, kidney functions, and liver functions. Twelve Sprague-Dawley rats were used as a model for this study that were divided into two groups; (i control and (ii treated group with phage FR38. For treated phage group, each rat was administered by 5 ml/kg bw of 1.59-107 pfu/ml of phage intragastric. The blood parameters were analysed on day 16. The results revealed that body and organs weight, erythrocyte, hematocrit, hemoglobin, leukocyte, total protein, creatinine, SGOT, and SGPT of phage treatment rats were not significantly different with the control rats on day 16 (P > 0.05. Therefore, this study showed was no effect of phage FR38 on body weight, blood chemistry, kidney and liver functions of the rat (P > 0.05.

Constraint on reconstructed f(R) gravity models from gravitational waves

Science.gov (United States)

Lee, Seokcheon

2018-06-01

The gravitational wave (GW) detection of a binary neutron star inspiral made by the Advanced LIGO and Advanced Virgo paves the unprecedented way for multi-messenger observations. The propagation speed of this GW can be scrutinized by comparing the arrival times between GW and neutrinos or photons. It provides the constraint on the mass of the graviton. f(R) gravity theories have the habitual non-zero mass gravitons in addition to usual massless ones. Previously, we show that the model independent f(R) gravity theories can be constructed from the both background evolution and the matter growth with one undetermined parameter. We show that this parameter can be constrained from the graviton mass bound obtained from GW detection. Thus, the GW detection provides the invaluable constraint on the validity of f(R) gravity theories.

Herbert Fröhlich a physicist ahead of his time

CERN Document Server

Hyland, G J

2015-01-01

This biography provides a stimulating and coherent blend of scientific and personal narratives describing the many achievements of the theoretical physicist Herbert Fröhlich. For more than half a century, Fröhlich was an internationally renowned and much respected figure who exerted a decisive influence, often as a ‘man ahead of his time’, in fields as diverse as meson theory and biology. Although best known for his contributions to the theory of dielectrics and superconductivity, he worked in many other fields, his most important legacy being the pioneering introduction quantum field-theoretical methods into condensed matter physics in 1952, which revolutionised the subsequent development of the subject. Gerard Hyland has written an absorbing and informative account, in which Herbert Fröhlich’s magnetic personality shines through.

77 FR 15755 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

Science.gov (United States)

2012-03-16

... Reports Report title: Consolidated Financial Statements for Bank Holding Companies. Agency form number: FR... operations. The FR Y-9C consists of standardized financial statements similar to the Federal Financial..., supporting statements and approved collection of information instruments are placed into OMB's public docket...

f(R in Holographic and Agegraphic Dark Energy Models and the Generalized Uncertainty Principle

Directory of Open Access Journals (Sweden)

Barun Majumder

2013-01-01

Full Text Available We studied a unified approach with the holographic, new agegraphic, and f(R dark energy model to construct the form of f(R which in general is responsible for the curvature driven explanation of the very early inflation along with presently observed late time acceleration. We considered the generalized uncertainty principle in our approach which incorporated the corrections in the entropy-area relation and thereby modified the energy densities for the cosmological dark energy models considered. We found that holographic and new agegraphic f(R gravity models can behave like phantom or quintessence models in the spatially flat FRW universe. We also found a distinct term in the form of f(R which goes as R 3 / 2 due to the consideration of the GUP modified energy densities. Although the presence of this term in the action can be important in explaining the early inflationary scenario, Capozziello et al. recently showed that f(R ~ R 3 / 2 leads to an accelerated expansion, that is, a negative value for the deceleration parameter q which fits well with SNeIa and WMAP data.

Forty-Sixth Meeting of the Technical Working Group on Fast Reactors (TWG-FR). Working Material

International Nuclear Information System (INIS)

2013-01-01

The objectives of the meeting were to: • Review the current status and the progress since the 45th TWG-FR meeting of FR and ADS technology development activities in IAEA Member States; • Review the activities (past, present and planned) of the IAEA’s project 1.1.5.3, “Support for fast reactor research, technology development and deployment” to ensure that they remain relevant to the needs of Member States; • Provide the experts group with updates to advise the IAEA on FR and ADS activities, including on proposals for relevant studies and reviews; • Serve as a means for exchanging information on national and international FR and ADS programmes; • Review the main achievements and outcomes of the “International Conference on Fast Reactors and Related Fuel Cycle: Safe Technologies and Sustainable Scenarios – FR13”, held on 4 – 7 March 2013 in Paris, France; • Promote the exchange of technical information by proposing topics for, and assisting in the organization of, IAEA Workshops and Technical Meetings for 2014-2015 and further, and • Review the IAEA’s concluded, on-going and planned coordinated research projects (CRPs) in the technical fields relevant to the TWG-FR (FRs and ADS), as well as coordination of the TWG-FR’s activities with other organizations and international initiatives (GIF, INPRO, NEA, Euratom, etc.)

Extension of loop quantum gravity to f(R) theories.

Science.gov (United States)

Zhang, Xiangdong; Ma, Yongge

2011-04-29

The four-dimensional metric f(R) theories of gravity are cast into connection-dynamical formalism with real su(2) connections as configuration variables. Through this formalism, the classical metric f(R) theories are quantized by extending the loop quantization scheme of general relativity. Our results imply that the nonperturbative quantization procedure of loop quantum gravity is valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

76 FR 36989 - Medical Devices; Exception From General Requirements for Informed Consent

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2011-06-24

...: I. Background A. Overview of Final Rule In the Federal Register of June 7, 2006 (71 FR 32827), FDA... contended that the rule will allow the use of experimental tests, which have an unknown rate of inaccurate... be entitled to withdraw previously collected data from the research database * * *'' (71 FR 32827 at...

76 FR 19524 - Privacy Act of 1974; Deletion of System of Records

Science.gov (United States)

2011-04-07

...), which was first published FR Vol. 52, No 155 dated August 12, 1987. The system of records known as... means to grant individuals access permissions to the resources of the Austin Data Processing Center. The... replaced by 87VA045, ``Automated Customer Registration System (ACRS)-VA'', which was published in FR Vol...

Editorial

Directory of Open Access Journals (Sweden)

Gregor Busslinger

2010-12-01

Anmerkung 1 Das EPZ existierte bis Mitte 2005. Zur Wegrationalisierung des EPZ vgl. Schär Sall und Burtscher (2006: Ethnopsychoanalyse im EthnologischPsychologischen Zentrum (EPZ der AsylOrganisation Zürich. Ein ethnopsychologischer Selbstversuch im Journal für Psychoanalyse, 47: 67–85. Journal für Psychoanalyse 51

78 FR 46499 - Change in Terminology: “Mental Retardation” to “Intellectual Disability”

Science.gov (United States)

2013-08-01

... Change in Terminology: ``Mental Retardation'' to ``Intellectual Disability'' AGENCY: Social Security... INFORMATION CONTACT: Cheryl Williams, Office of Medical Listings Improvement, Social Security Administration... terminology.\\3\\ \\2\\ Public Law 111-256. \\3\\ See 77 FR 29002 and 77 FR 6022-01. Public Comments In the NPRM, we...

SN 2012fr

DEFF Research Database (Denmark)

Contreras, Carlos; Phillips, M. M.; Burns, Christopher R.

2018-01-01

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epo...

String duality transformations in f(R) gravity from Noether symmetry approach

Energy Technology Data Exchange (ETDEWEB)

Capozziello, Salvatore [Dipartimento di Fisica, Università di Napoli ' ' Federico II' ' , Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); Gionti, Gabriele S.J. [Specola Vaticana, Vatican City, V-00120, Vatican City State (Vatican City State, Holy See); Vernieri, Daniele, E-mail: capozziello@na.inf.it, E-mail: ggionti@as.arizona.edu, E-mail: vernieri@iap.fr [Sorbonne Universités, UPMC Univ Paris 6 et CNRS, UMR 7095, Institut d' Astrophysique de Paris, GReCO, 98bis Bd Arago, 75014 Paris (France)

2016-01-01

We select f(R) gravity models that undergo scale factor duality transformations. As a starting point, we consider the tree-level effective gravitational action of bosonic String Theory coupled with the dilaton field. This theory inherits the Busher's duality of its parent String Theory. Using conformal transformations of the metric tensor, it is possible to map the tree-level dilaton-graviton string effective action into f(R) gravity, relating the dilaton field to the Ricci scalar curvature. Furthermore, the duality can be framed under the standard of Noether symmetries and exact cosmological solutions are derived. Using suitable changes of variables, the string-based f(R) Lagrangians are shown in cases where the duality transformation becomes a parity inversion.

String duality transformations in f(R) gravity from Noether symmetry approach

International Nuclear Information System (INIS)

Capozziello, Salvatore; Gionti, Gabriele S.J.; Vernieri, Daniele

2016-01-01

We select f(R) gravity models that undergo scale factor duality transformations. As a starting point, we consider the tree-level effective gravitational action of bosonic String Theory coupled with the dilaton field. This theory inherits the Busher's duality of its parent String Theory. Using conformal transformations of the metric tensor, it is possible to map the tree-level dilaton-graviton string effective action into f(R) gravity, relating the dilaton field to the Ricci scalar curvature. Furthermore, the duality can be framed under the standard of Noether symmetries and exact cosmological solutions are derived. Using suitable changes of variables, the string-based f(R) Lagrangians are shown in cases where the duality transformation becomes a parity inversion

78 FR 24785 - Public Hearing

Science.gov (United States)

2013-04-26

... Spring, Logan Branch Watershed), Spring Township, Centre County, Pa. Application for surface water...: April 19, 2013. Paul O. Swartz, Executive Director. [FR Doc. 2013-09887 Filed 4-25-13; 8:45 am] BILLING...

Reminder of Lagrange-Hamilton formalism and of the corpuscular optics invariants; Rappel du formalisme de Lagrange-Hamilton et sur les invariants de l'optique corpusculaire

Energy Technology Data Exchange (ETDEWEB)

Griess, F.

1958-03-14

Hamiltonian formalism - Canonical transformations - Invariants of Liouville, Helmholtz-Lagrange, Busch, Stoermer and Lagrange - Synchrotron's Hamiltonian - Betatron oscillation damping. (author) [French] Formalisme Hamiltonien. Transformations canoniques. Invariants de Liouville, Helmholtz-Lagrange, Busch, Stoermer et Lagrange, Hamiltonien pour le synchrotron, Amortissement des oscillations betatrons (auteur)

78 FR 11858 - Applications for New Awards; Arts in Education Model Development and Dissemination Program

Science.gov (United States)

2013-02-20

... on December 15, 2010 (75 FR 78486), and corrected on May 12, 2011 (76 FR 27637). Arts includes music... baseline outcome measurement is compared with a post treatment measure, the treatment would then be stopped...

76 FR 56242 - Energy Northwest; Establishment of Atomic Safety and Licensing Board

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2011-09-12

... Northwest's Columbia Generating Station,'' was received via E-Filing on August 22, 2011.\\1\\ \\1\\ On August 22... with the NRC E-Filing rule, which the NRC promulgated in August 2007 (72 FR 49,139). Issued at..., 1972, published in the Federal Register, 37 FR 28,710 (1972), and the Commission's regulations, see, e...

77 FR 4999 - Decision and Order Granting a Waiver to LG From the Department of Energy Clothes Washer Test...

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2012-02-01

..., 2011)); (76 FR 79666 (Dec. 22, 2011)) and Samsung (76 FR 13169 (Mar. 10, 2011)); 76 FR 50207 (Aug. 12... consideration of all the material that was submitted by LG, the waivers granted to Whirlpool, GE, Samsung and... clothes washer products for compliance, marketing, or other purposes only to the extent that such products...

78 FR 47024 - Excepted Service

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2013-08-02

... Readiness). Department of Education......... Office of the Under Executive Director, DB130022 4/3/2013... Kaplan, Acting Director. [FR Doc. 2013-18607 Filed 8-1-13; 8:45 am] BILLING CODE 6325-39-P ...

77 FR 32970 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

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2012-06-04

... more granular data reported in the FR Y-14Q and the FR Y-14M schedules for their Consolidated Financial... collections of information. Copies of the Paperwork Reduction Act Submission, supporting statements and... nonbank financial companies supervised by the Federal Reserve are subject to enhanced risk-based and...

77 FR 56842 - Agency Information Collection Activities: Announcement of Board Approval Under Delegated...

Science.gov (United States)

2012-09-14

... Organizational Structure, Annual Report of Bank Holding Companies, and Annual Report of Foreign Banking... supplement to the FR Y-10) a one-time verification of each SLHC's organizational structure. After considering... the Report of Changes in Organizational Structure. Agency form number: FR Y-10E. OMB control number...

Stability of the Einstein static universe in f(R, T) gravity

Energy Technology Data Exchange (ETDEWEB)

Shabani, Hamid [University of Sistan and Baluchestan, Physics Department, Faculty of Sciences, Zahedan (Iran, Islamic Republic of); Ziaie, Amir Hadi [Kahnooj Branch, Islamic Azad University, Department of Physics, Kerman (Iran, Islamic Republic of)

2017-01-15

The Einstein static (ES) universe has played a major role in various emergent scenarios recently proposed in order to cure the problem of the initial singularity of the standard model of cosmology. In the model we address, we study the existence and stability of an ES universe in the context of f(R, T) modified theories of gravity. Considering specific forms of the f(R, T) function, we seek for the existence of solutions representing ES state. Using dynamical system techniques along with numerical analysis, we find two classes of solutions: the first one is always unstable of the saddle type, while the second is always stable so that its dynamical behavior corresponds to a center equilibrium point. The importance of the second class of solutions is due to the significant role they play in constructing non-singular emergent models in which the universe could have experienced past-eternally a series of infinite oscillations about such an initial static state after which it enters, through a suitable physical mechanism, to an inflationary era. Considering specific forms for the functionality of f(R, T), we show that this theory is capable of providing cosmological solutions which admit emergent universe (EU) scenarios. We also investigate homogeneous scalar perturbations for the mentioned models. The stability regions of the solutions are parametrized by a linear equation of state (EoS) parameter and other free parameters that will be introduced for the models. Our results suggest that modifications in f(R, T) gravity would lead to stable solutions which are unstable in f(R) gravity model. (orig.)

Stability of the Einstein static universe in f(R, T) gravity

International Nuclear Information System (INIS)

Shabani, Hamid; Ziaie, Amir Hadi

2017-01-01

The Einstein static (ES) universe has played a major role in various emergent scenarios recently proposed in order to cure the problem of the initial singularity of the standard model of cosmology. In the model we address, we study the existence and stability of an ES universe in the context of f(R, T) modified theories of gravity. Considering specific forms of the f(R, T) function, we seek for the existence of solutions representing ES state. Using dynamical system techniques along with numerical analysis, we find two classes of solutions: the first one is always unstable of the saddle type, while the second is always stable so that its dynamical behavior corresponds to a center equilibrium point. The importance of the second class of solutions is due to the significant role they play in constructing non-singular emergent models in which the universe could have experienced past-eternally a series of infinite oscillations about such an initial static state after which it enters, through a suitable physical mechanism, to an inflationary era. Considering specific forms for the functionality of f(R, T), we show that this theory is capable of providing cosmological solutions which admit emergent universe (EU) scenarios. We also investigate homogeneous scalar perturbations for the mentioned models. The stability regions of the solutions are parametrized by a linear equation of state (EoS) parameter and other free parameters that will be introduced for the models. Our results suggest that modifications in f(R, T) gravity would lead to stable solutions which are unstable in f(R) gravity model. (orig.)

78 FR 27058 - Approval and Promulgation of Air Quality Implementation Plans; Louisiana; Approval of Section 110...

Science.gov (United States)

2013-05-09

... and Fuels (69 FR 38958); and (4) EPA's Locomotive and Marine Compression-Ignition Engines rule (73 FR... Products Group IV (Miscellaneous Metal Products Coatings, Plastic Parts Coatings, Auto and Light-Duty Truck...

78 FR 40778 - Notice of Meeting

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2013-07-08

... information. ADDRESSES: Mayflower Renaissance Hotel Washington, 1127 Connecticut Ave. NW., Washington DC 20036..., 2013. Diane Janosek, Chief Legal Officer, Privacy and Civil Liberties Oversight Board. [FR Doc. 2013...

77 FR 71097 - Addition of Certain Persons to the Entity List

Science.gov (United States)

2012-11-29

... Trading FZE, P.O Box 10559, Ras Al Khaimah, U.A.E.; and Ras Al Khaimah Free Trade Zone (RAKFTZ), U.A.E..., the Emirati entity, Infotec, a.k.a., Info Tech, Ras Al Khaimah Free Trade Zone (RAKFTZ), U.A.E. The... EAR. (See Sec. 77 FR [INSERT FR --I. Tec Trading FZE, 744.11 of the PAGE NUMBER] P.O. Box 10559, Ras...

Generation of spherically symmetric metrics in f(R) gravity

Energy Technology Data Exchange (ETDEWEB)

Amirabi, Z.; Halilsoy, M.; Mazharimousavi, S.H. [Eastern Mediterranean University, Department of Physics, Gazimagusa (Turkey)

2016-06-15

In D-dimensional spherically symmetric f(R) gravity there are three unknown functions to be determined from the fourth order differential equations. It is shown that the system remarkably may be integrated to relate two functions through the third one to provide a reduction to second order equations accompanied with a large class of potential solutions. The third function, which acts as the generator of the process, is F(R) = (df(R))/(dR). We recall that our generating function has been employed as a scalar field with an accompanying self-interacting potential previously, which is entirely different from our approach. Reduction of f(R) theory into a system of equations seems to be efficient enough to generate a solution corresponding to each generating function. As particular examples, besides the known ones, we obtain new black hole solutions in any dimension D. We further extend our analysis to cover non-zero energy-momentum tensors. Global monopole and Maxwell sources are given as examples. (orig.)

Probing the f(R) formalism through gravitational wave polarizations

International Nuclear Information System (INIS)

Alves, M.E.S.; Miranda, O.D.; Araujo, J.C.N. de

2009-01-01

The direct observation of gravitational waves (GW) in the near future, and the corresponding determination of the number of independent polarizations, is a powerful tool to test general relativity and alternative theories of gravity. In the present work we use the Newman-Penrose formalism to characterize GWs in quadratic gravity and in a particular class of f(R) Lagrangians. We find that both quadratic gravity and the f(R) theory belong to the most general invariant class of GWs, i.e., they can present up to six independent polarizations of GWs. For a particular combination of the parameters, we find that quadratic gravity can present up to five polarizations states. On the other hand, if we use the Palatini approach for f(R) theories, GWs present only the usual two transverse-traceless polarizations such as in general relativity. Thus, we conclude that the observation of GWs can strongly constrain the suitable formalism for these theories.

75 FR 58328 - Nebraska: Final Authorization of State Hazardous Waste Management Program Revisions

Science.gov (United States)

2010-09-24

... (67 FR 48393). Specifically, the commenter argued that the Phase IV Land Disposal Restriction (LDR... Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001), because it is not a... inconsistent with applicable law for EPA, when it reviews a State authorization application, to require the use...

77 FR 34229 - Idaho: Final Authorization of State Hazardous Waste Management Program; Revision

Science.gov (United States)

2012-06-11

... waste regulated under RCRA. In 2003, EPA proposed the sector as an enforcement priority for fiscal years...) Amendments (73 FR 18970, April 8, 2008); F019 Exemption for Wastewater Treatment Sludges from Auto... Comparable Fuel Exclusion (75 FR 33712, June 15, 2010). The federal regulation for the Export of Shipments of...

77 FR 68076 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Redesignation of...

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2012-11-15

... preserve the environmental benefits provided by CAIR, North Carolina v. EPA, 550 F.3d 1176, 1178 (DC Cir... CSR 19. See 71 FR 64468 (November 2, 2006) (approving NSR program into the SIP) and 77 FR 63736...

75 FR 47540 - Extension of the Award Period for Certain Minority Business Enterprise Centers

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2010-08-06

... DEPARTMENT OF COMMERCE Minority Business Development Agency [Docket No.: 100730316-0318-02... Development Agency, Commerce. ACTION: Notice. SUMMARY: The Minority Business Development Agency (MBDA... Alabama MBEC Mobile Area Chamber of State of Alabama........ 71 FR 42351, as amended by 71 FR 45773 and by...

75 FR 5545 - Explosives

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2010-02-03

... the Storage of Ammonium Nitrate. OSHA subsequently made several minor revisions to the standard (37 FR... explosives; storing ammonium nitrate; and storing small arms ammunition, small arms primers, and small arms..., which is extremely widespread, causes lung disease, silicosis and lung cancer. Terminating the...

Jean Frémon/Rue du Regard

OpenAIRE

Mokhtari, Sylvie

2012-01-01

La prose de Jean Frémon sur la peinture se déploie ici en 48 courts textes, dont une bonne moitié d’entre eux avait déjà connu une première édition dans des revues. Abordés isolément, les œuvres de Bill Viola, David Hockney, Antoni Tàpies, Gilles Aillaud, Roy Lichtenstein… sont soumises à la traduction littéraire qu’en donne le « regardeur de tableau, jardinier, journalier, vagabond » et écrivain. J. Frémon chemine entre art et littérature à la rencontre d’artistes qui l’interpellent dans l’H...