WorldWideScience

Sample records for investigating high field

  1. High range electromagnetic fields. Experimental investigations

    International Nuclear Information System (INIS)

    Comino, E.; Boccardo, D.; Quaglino, A.

    2001-01-01

    It has been often discussed on the health effects from the electromagnetic fields, and nowadays this theme is particularly controlled and studied by the research-workers. It needs to know what is the risk connected to the exposure to the electromagnetism during a short or a long quantity of time and what are the health pathologies caused by the continue exposure. On one hand the results from epidemiological research can not still define the effect of the dose, on the other hand the legislative frame is variously fragmented and based on cautious concepts. But in this work, under the collaboration of Energy Resources Laboratory in Lausanne and the Geo resources and Territory Department in Turin University, are presented the early results on the experiments got out on high frequency (950 MHZ) in order to give a contribution to the debate between the scientific community and the public opinion [it

  2. Investigating High Field Gravity using Astrophysical Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Elliott D.; /SLAC

    2008-02-01

    The purpose of these lectures is to introduce particle physicists to astrophysical techniques. These techniques can help us understand certain phenomena important to particle physics that are currently impossible to address using standard particle physics experimental techniques. As the subject matter is vast, compromises are necessary in order to convey the central ideas to the reader. Many general references are included for those who want to learn more. The paragraphs below elaborate on the structure of these lectures. I hope this discussion will clarify my motivation and make the lectures easier to follow. The lectures begin with a brief review of more theoretical ideas. First, elements of general relativity are reviewed, concentrating on those aspects that are needed to understand compact stellar objects (white dwarf stars, neutron stars, and black holes). I then review the equations of state of these objects, concentrating on the simplest standard models from astrophysics. After these mathematical preliminaries, Sec. 2(c) discusses 'The End State of Stars'. Most of this section also uses the simplest standard models. However, as these lectures are for particle physicists, I also discuss some of the more recent approaches to the equation of state of very dense compact objects. These particle-physics-motivated equations of state can dramatically change how we view the formation of black holes. Section 3 focuses on the properties of the objects that we want to characterize and measure. X-ray binary systems and Active Galactic Nuclei (AGN) are stressed because the lectures center on understanding very dense stellar objects, black hole candidates (BHCs), and their accompanying high gravitational fields. The use of x-ray timing and gamma-ray experiments is also introduced in this section. Sections 4 and 5 review information from x-ray and gamma-ray experiments. These sections also discuss the current state of the art in x-ray and gamma-ray satellite

  3. Field test investigation of high sensitivity fiber optic seismic geophone

    Science.gov (United States)

    Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

    2017-10-01

    Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.

  4. The Investigation of Field Plate Design in 500 V High Voltage NLDMOS

    Directory of Open Access Journals (Sweden)

    Donghua Liu

    2015-01-01

    Full Text Available This paper presents a 500 V high voltage NLDMOS with breakdown voltage (VBD improved by field plate technology. Effect of metal field plate (MFP and polysilicon field plate (PFP on breakdown voltage improvement of high voltage NLDMOS is studied. The coeffect of MFP and PFP on drain side has also been investigated. A 500 V NLDMOS is demonstrated with a 37 μm drift length and optimized MFP and PFP design. Finally the breakdown voltage 590 V and excellent on-resistance performance (Rsp = 7.88 ohm * mm2 are achieved.

  5. Investigation of material properties by NMR in low and high magnetic fields

    International Nuclear Information System (INIS)

    Rata, D.G.

    2006-01-01

    In this work the experiments have been performed at both low and high field. The experiments cover various domains from simple relaxation experiments in low field to diffusion and spin-diffusion in high field. The applications of low-field investigations are: - quality control of chemical products. - water content determination inside of the walls of buildings. - determination of multilayer polymer coatings on a concrete. In high-field NMR several alkane molecules swollen at equilibrium in cross-linked natural rubber samples have been investigated and analyzed based on the assumptions of the Vrentras theory. A small diffusion anisotropy of the order of 10% has been discovered because of a deformation of free volume under compression. The anisotropy increases with the cross-link density and the compression ratio. The results presented in this study show that the solvent size influences the anisotropy of the diffusion process through the size parameter. The spin-diffusion measurements have been performed on Stanyl samples with different aged samples, at controlled temperature conditions. (orig.)

  6. Investigation of material properties by NMR in low and high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Rata, D.G.

    2006-07-10

    In this work the experiments have been performed at both low and high field. The experiments cover various domains from simple relaxation experiments in low field to diffusion and spin-diffusion in high field. The applications of low-field investigations are: - quality control of chemical products. - water content determination inside of the walls of buildings. - determination of multilayer polymer coatings on a concrete. In high-field NMR several alkane molecules swollen at equilibrium in cross-linked natural rubber samples have been investigated and analyzed based on the assumptions of the Vrentras theory. A small diffusion anisotropy of the order of 10% has been discovered because of a deformation of free volume under compression. The anisotropy increases with the cross-link density and the compression ratio. The results presented in this study show that the solvent size influences the anisotropy of the diffusion process through the size parameter. The spin-diffusion measurements have been performed on Stanyl samples with different aged samples, at controlled temperature conditions. (orig.)

  7. Installation for microwave investigations of high-temperature superconductivity in magnetic field

    CERN Document Server

    Akhvlediani, I G; Mamniashvili, G I; Chigvinadze, D G

    2002-01-01

    Paper describes advanced EPR-spectrometer RE 1306 designed to investigate into structure of magnetic flux in high-temperature superconductors (HTSC). To measure in low fields one uses power source generating current within 0-600 mA limits and 10-500 Gauss field. To ensure temperature studies of HTSC within up to approx 15 K range one used helium and nitrogen cold steam blowing through resonator of EPR-spectrometer. To stabilize specimen temperature prior to cold steams enter double tube one fixed one more heater

  8. An investigation of methods for neutron dose measurement in high temperature irradiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Kosako, Toshisou; Sugiura, Nobuyuki [Tokyo Univ. (Japan); Kudo, Kazuhiko [Kyushu Univ., Fukuoka (Japan)] [and others

    2000-10-01

    The Japan Atomic Energy Research Institute (JAERI) has been conducting the innovative basic research on high temperature since 1994, which is a series of high temperature irradiation studies using the High Temperature Engineering Test Reactor (HTTR). 'The Task Group for Evaluation of Irradiation Dose under High Temperature Radiation' was founded in the HTTR Utilization Research Committee, which is the promoting body of the innovative basic research. The present report is a summary of investigation which has been made by the Task Group on the present status and subjects of research and development of neutron detectors in high temperature irradiation fields, in view of contributing to high temperature irradiation research using the HTTR. Detectors investigated here in the domestic survey are the following five kinds of in-core detectors: 1) small fission counter, 2) small fission chamber, 3) self-powered detector, 4) activation detector, and 5) optical fiber. In addition, the research and development status in Russia has been investigated. The present report will also be useful as nuclear instrumentation of high temperature gas-cooled reactors. (author)

  9. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  10. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    International Nuclear Information System (INIS)

    Brunckhorst, Elin

    2009-01-01

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a 10 B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with 6 Li and 7 Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined with an

  11. Engaging High School Students in Investigative STEM Activities Based on Field Research

    Science.gov (United States)

    Stevens, J.; Sheriff, M. M.; Washington, D. S.; Putnam, A. E.; Strand, P.; Radue, M. J.

    2017-12-01

    The lead author, an Environmental Science teacher at Gary Comer High School (GCHS), a public charter on the South Side of Chicago, accompanied two students over the course of two summers to conduct field research in remote mountain ranges of interior Asia. The expeditions were funded by the National Science Foundation and orchestrated collaboratively with PI Putnam with the purposes of bringing along high school students and teachers (1) to introduce students from urban areas to practical Earth Science and (2) to bolster the Environmental Science curriculum at GCHS by providing real world events to relate to classroom learning. During the first field trip, a student from GCHS and the lead author traveled to western Mongolia to participate in collecting samples for cosmogenic-nuclide dating of glacial landforms. The student performed all parts of sample collection and used the data to create a poster analyzing the rate of recession of the Potanin Glacier. She went on to present her findings at the AGU Fall Meeting 2016. At GCHS, she assisted the teacher in lessons about climate change. Next year she will be attending the University of Vermont to pursue a major in a STEM field. The second student traveled to the Tibetan Plateau in China and also participated fully in sampling activities. She plans on presenting her project on creating 3D models of sample boulders at the AGU Meeting in 2017. She will present her findings to the rest of the student body at GCHS, assist with pertinent Environmental Science lessons for Freshmen, and explain her experience at the Gary Comer Middle School. The lead author faced several restrictions in the classroom due to standardized testing requirements, leading to more focus on testing skills rather than investigative learning. Next year the focus will switch from ACT to SAT standards, allowing more freedom to pursue investigative lessons. The success of adding information on the field experience will be assessed at the end of the 2017

  12. A method for radiobiological investigations in radiation fields with different LET and high dose rates

    International Nuclear Information System (INIS)

    Grundler, W.

    1976-01-01

    For investigations: 1. Performed in the field of radiobiology with different LET-radiation and a relatively high background dose rate of one component (e.g. investigations with fast and intermediate reactor neutrons) 2. Concerning radiation risk studies within a wide range 3. Of irradiations, covering a long time period (up to 100 days) a test system is necessary which on the one hand makes it possible to analyze the influence of different LET radiation and secondly shows a relative radiation resistant behaviour and allows a simple cell cycle regulation. A survey is given upon the installed device of a simple cell observation method, the biological test system used and the analysis of effects caused by dose, repair and LET. It is possible to analyze the behaviour of the nonsurvival cells and to demonstrate different reactions of the test parameters to the radiation of different LET. (author)

  13. Investigating Jeffery-Hamel flow with high magnetic field and nanoparticle by HPM and AGM

    Science.gov (United States)

    Rostami, A.; Akbari, M.; Ganji, D.; Heydari, S.

    2014-12-01

    In this study, the effects of magnetic field and nanoparticle on the Jeffery-Hamel flow are studied using two powerful analytical methods, Homotopy Perturbation Method (HPM) and a simple and innovative approach which we have named it Akbari-Ganji's Method(AGM). Comparisons have been made between HPM, AGM and Numerical Method and the acquired results show that these methods have high accuracy for different values of α, Hartmann numbers, and Reynolds numbers. The flow field inside the divergent channel is studied for various values of Hartmann number and angle of channel. The effect of nanoparticle volume fraction in the absence of magnetic field is investigated. It is necessary to represent some of the advantages of choosing the new method, AGM, for solving nonlinear differential equations as follows: AGM is a very suitable computational process and is applicable for solving various nonlinear differential equations. Moreover, in AGM by solving a set of algebraic equations, complicated nonlinear equations can easily be solved and without any mathematical operations such as integration, the solution of the problem can be obtained very simply and easily. It is notable that this solution procedure, AGM, can help students with intermediate mathematical knowledge to solve a broad range of complicated nonlinear differential equations.

  14. High field Moessbauer and magnetic investigations of Pr0.73Fe4Sb12

    International Nuclear Information System (INIS)

    Reissner, Michael; Bauer, Ernst; Steiner, Walter; Rogl, Peter

    2004-01-01

    In accordance with the filling factor determined by X-ray investigations two Fe sites were identified in the in-field 57 Fe Moessbauer spectra. The derived internal fields at 4.2 K were small (0.35 and 1.45 T at external fields of 13.5 T), whereas from magnetic measurements μ eff ∼2.7 μ B was estimated for the Fe 4 Sb 12 -sublattice

  15. Theoretical investigation of magnetic property in paramagnetic neodymium gallium garnet under high magnetic field

    International Nuclear Information System (INIS)

    Wang Wei; Liu Gongqiang; Wang Jinhui

    2006-01-01

    The magnetic property in neodymium gallium garnet (NdGaG) is studied by the quantum theory. The ground configuration split states are calculated taking into account the spin-orbit interaction and crystal field effect. Taking account of the Nd-Nd exchange interaction, a good agreement between experimental and theoretical values can be obtained for the variation of the magnetic moment with the external magnetic field under 'extreme' conditions (low temperature and high magnetic field). Moreover, the temperature dependence of magnetic moment and the magnetic susceptibility χ is also discussed. Above 30 K, the magnetization (M) shows a linear field (H e ) dependence

  16. Steering Electromagnetic Fields in MRI: Investigating Radiofrequency Field Interactions with Endogenous and External Dielectric Materials for Improved Coil Performance at High Field

    Science.gov (United States)

    Vaidya, Manushka

    Although 1.5 and 3 Tesla (T) magnetic resonance (MR) systems remain the clinical standard, the number of 7 T MR systems has increased over the past decade because of the promise of higher signal-to-noise ratio (SNR), which can translate to images with higher resolution, improved image quality and faster acquisition times. However, there are a number of technical challenges that have prevented exploiting the full potential of ultra-high field (≥ 7 T) MR imaging (MRI), such as the inhomogeneous distribution of the radiofrequency (RF) electromagnetic field and specific energy absorption rate (SAR), which can compromise image quality and patient safety. To better understand the origin of these issues, we first investigated the dependence of the spatial distribution of the magnetic field associated with a surface RF coil on the operating frequency and electrical properties of the sample. Our results demonstrated that the asymmetries between the transmit (B1+) and receive (B 1-) circularly polarized components of the magnetic field, which are in part responsible for RF inhomogeneity, depend on the electric conductivity of the sample. On the other hand, when sample conductivity is low, a high relative permittivity can result in an inhomogeneous RF field distribution, due to significant constructive and destructive interference patterns between forward and reflected propagating magnetic field within the sample. We then investigated the use of high permittivity materials (HPMs) as a method to alter the field distribution and improve transmit and receive coil performance in MRI. We showed that HPM placed at a distance from an RF loop coil can passively shape the field within the sample. Our results showed improvement in transmit and receive sensitivity overlap, extension of coil field-of-view, and enhancement in transmit/receive efficiency. We demonstrated the utility of this concept by employing HPM to improve performance of an existing commercial head coil for the

  17. Parallel and perpendicular field investigations of coupled high {Tc} multilayer structures

    Energy Technology Data Exchange (ETDEWEB)

    Fivat, P.; Triscone, J.M.; Andersson, M.; Decroux, M.; Fischer, O. [Univ. of Geneva (Switzerland)

    1994-12-31

    The authors report on the behavior of high {Tc} superconductors coupled multilayer structures in magnetic field parallel and perpendicular to the ab plane. These structures consist of N 24{angstrom} thick DyBa{sub 2}Cu{sub 3}O{sub 7} layers, each separated from the next by 96{angstrom} of an (Y{sub 0.45}Pr{sub 0.55})Ba{sub 2}Cu{sub 3}O{sub 7} alloy. This alloy allows a coupling of the superconducting layers as demonstrated by measurements of the activation energies for flux motion U. For a N = 15 sample one finds, in perpendicular fields, that a correlated motion of pancake vortices occurs with a characteristic length of about 480 {angstrom}. Additionally, U is found to be proportional to logB at low fields while at higher fields a power law behavior is observed. In parallel field they find U to be field independent up to 1T, suggesting that the vortices are trapped at low fields in the material where weak superconductivity is induced by proximity effect.

  18. MgB_{2} nonlinear properties investigated under localized high rf magnetic field excitation

    Directory of Open Access Journals (Sweden)

    Tamin Tai

    2012-12-01

    Full Text Available The high transition temperature and low surface resistance of MgB_{2} attracts interest in its potential application in superconducting radio frequency accelerating cavities. However, compared to traditional Nb cavities, the viability of MgB_{2} at high rf fields is still open to question. Our approach is to study the nonlinear electrodynamics of the material under localized rf magnetic fields. Because of the presence of the small superconducting gap in the π band, the nonlinear response of MgB_{2} at low temperature is potentially complicated compared to a single-gap s-wave superconductor such as Nb. Understanding the mechanisms of nonlinearity coming from the two-band structure of MgB_{2}, as well as extrinsic sources of nonlinearity, is an urgent requirement. A localized and strong rf magnetic field, created by a magnetic write head, is integrated into our nonlinear-Meissner-effect scanning microwave microscope [T. Tai et al., IEEE Trans. Appl. Supercond. 21, 2615 (2011ITASE91051-822310.1109/TASC.2010.2096531]. MgB_{2} films with thickness 50 nm, fabricated by a hybrid physical-chemical vapor deposition technique on dielectric substrates, are measured at a fixed location and show a strongly temperature-dependent third harmonic response. We propose that several possible mechanisms are responsible for this nonlinear response.

  19. Physics Laboratory Investigation of Vocational High School Field Stone and Concrete Construction Techniques in the Central Java Province (Indonesia)

    Science.gov (United States)

    Purwandari, Ristiana Dyah

    2015-01-01

    The investigation aims in this study were to uncover the observations of infrastructures and physics laboratory in vocational high school for Stone and Concrete Construction Techniques Expertise Field or Teknik Konstruksi Batu dan Beton (TKBB)'s in Purwokerto Central Java Province, mapping the Vocational High School or Sekolah Menengah Kejuruan…

  20. Analytical Investigation of Jeffery-Hamel Flow with High Magnetic Field and Nano Particle by RVIM

    International Nuclear Information System (INIS)

    Imani, A. A.; Rostamian, Y.; Ganji, D. D.; Rokni, H. B.

    2012-01-01

    Many researchers have been interested in application of mathematical methods to find analytical solutions of nonlinear equations and for this purpose, new methods have been developed. One of the newest analytical methods to solve nonlinear equations is Reconstruction of variational Iteration Method which is an accurate and a rapid convergence method in finding the approximate solution for nonlinear equations. By applying Laplace Transform, Reconstruction of variational Iteration Method overcomes the difficulty of the perturbation techniques and other variational methods in case of using small parameters and Lagrange multipliers, respectively. In this study Reconstruction of variational Iteration Method is applied for the effects of magnetic field and nano particle on the Jeffery-Hamel flow. The traditional Navier-Stokes equation of fluid mechanics and Maxwell's electromagnetism governing equations are reduced to nonlinear ordinary differential equations to model the problem. The flow field inside the divergent channel is studied for various values of Hartmann number and angle of channel. Finally the effect of nano particle volume fraction in the absence of magnetic field is investigated, too. The validity of Reconstruction of variational Iteration Method method is ascertained by comparing our results with numerical (Runge Kutta method) results.

  1. The Juno Magnetic Field Investigation

    DEFF Research Database (Denmark)

    Connerney, J. E. P.; Benn, Mathias; Bjarnø, Jonas Bækby

    2017-01-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter’s planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor ...

  2. Investigation of high mobility pseudomorphic SiGe p-channels in Si MOSFETS at low and high electric fields

    International Nuclear Information System (INIS)

    Palmer, Martin John

    2001-01-01

    Silicon Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) for high speed, high current applications are rapidly approaching the physical and financial limits of the technology. This opens opportunities for the incorporation of materials with intrinsically better transport characteristics. An alloy of silicon and germanium is one such material that is gaining much recognition as the active component of MOSFETs and as the secondary structures (such as the gate electrode). This work examines a batch of buried channel Si 0.64 Ge 0.36 p-MOSFETs, with a minimum effective length of 0.35 μm, under different bias conditions and at different temperatures. High current and transconductance enhancements are apparent at long gate lengths. The carrier mobility is up to a factor of 2.5 times that of silicon at room temperature and 7.5 times at 4 K. A clear trend of decreasing peak mobility with decreasing silicon cap thickness is evident. Simulations show that scattering caused by the roughness of the SiO 2 /Si interface dominates, rather than alloy scattering or Si/SiGe roughness, even for a buried channel. This scattering increases with the proximity of the carriers to the interface. An increase of interface trap density with decreasing cap thickness, demonstrates that segregated germanium exists some distance into the cap and interferes with the oxidation process. This will increase scattering through increased SiO 2 /Si roughness and increased trapped charge. The short channel, high field results are comparable or slightly worse than those of silicon due to lower saturation drift velocity. However, fitting to a drift-diffusion model shows an apparent increase in saturation velocity for short channels, especially at low temperatures. This effect correlates with the low field mobility and is greater for devices containing SiGe. This is an indication of velocity overshoot, which may enhance the performance of SiGe MOSFETs at deep submicron gate lengths. (author)

  3. High-throughput investigation of orientations effect on nanoscale magnetization reversal in cobalt ferrite thin films induced by electric field

    Science.gov (United States)

    Dhanapal, Pravarthana; Guo, Shanshan; Wang, Baomin; Yang, Huali; Agarwal, Sandeep; Zhan, Qingfeng; Li, Run-Wei

    2017-10-01

    The magnetoelectric device concept which enables the non-volatile electric field control of magnetism needs to be investigated for the development of practical information storage devices. In this aspect, the emerging field of magneto-ionics based on the modulation of magnetism by field-driven ion migration is promising because it only requires a simple sample structure in the solid state and has good cyclability. However, the degree of ion migration within the magnetic structure is strongly dependent on the crystal orientations. Since the epitaxial films growing on the commercial single crystal substrates have limited orientations, the ability of magnetism modulated by field-driven ion migration cannot be optimized and understood by using these data. In this work, we utilized the high-throughput synthesis approach, namely, combinatorial substrate epitaxy, which utilizes a polycrystalline substrate. This provides a platform to develop and understand the degree of ionic migration in different orientations of the model system CoFe2O4 (CFO) films. The library of electric driven nanoscale magnetization reversal data of CFO with different orientations was obtained by applying the electric field in the same region of known CFO grain orientations. It was determined from the analysis that the [110] crystal direction exhibits the maximum nanoscale magnetization reversal ratio. This is mainly attributed to the ease Co2+ migration in the [110] direction under the electric field assisted by a Fe3+ and oxygen vacancies.

  4. Investigation of fringing electric field effect on high-resolution blue phase liquid crystal spatial light modulator.

    Science.gov (United States)

    Yan, Jing; Guo, Zhengbo; Xing, Yufei; Li, Qing

    2015-08-20

    The fringing electric field effect which determines the performance of a high-resolution blue phase liquid crystal spatial light modulator (BPLC-SLM) is investigated by numerical modeling. The BPLC-SLM is polarization-dependent due to the transverse electric field component. The physical mechanism of the phase profile properties for different polarization states is analyzed. General design issues related to the BPLC-SLM configuration and phase profile properties are discussed. Notably, the material parameters and cell gap thickness are both optimized to obtain a low operation voltage (V2π=26.07  V). This work provides fundamental understanding for the feasibility of low operation voltage and high spatial resolution BPLC-SLM.

  5. Toward increased concentration sensitivity for continuous wave EPR investigations of spin-labeled biological macromolecules at high fields

    Science.gov (United States)

    Song, Likai; Liu, Zhanglong; Kaur, Pavanjeet; Esquiaqui, Jackie M.; Hunter, Robert I.; Hill, Stephen; Smith, Graham M.; Fanucci, Gail E.

    2016-04-01

    High-field, high-frequency electron paramagnetic resonance (EPR) spectroscopy at W-(∼94 GHz) and D-band (∼140 GHz) is important for investigating the conformational dynamics of flexible biological macromolecules because this frequency range has increased spectral sensitivity to nitroxide motion over the 100 ps to 2 ns regime. However, low concentration sensitivity remains a roadblock for studying aqueous samples at high magnetic fields. Here, we examine the sensitivity of a non-resonant thin-layer cylindrical sample holder, coupled to a quasi-optical induction-mode W-band EPR spectrometer (HiPER), for continuous wave (CW) EPR analyses of: (i) the aqueous nitroxide standard, TEMPO; (ii) the unstructured to α-helical transition of a model IDP protein; and (iii) the base-stacking transition in a kink-turn motif of a large 232 nt RNA. For sample volumes of ∼50 μL, concentration sensitivities of 2-20 μM were achieved, representing a ∼10-fold enhancement compared to a cylindrical TE011 resonator on a commercial Bruker W-band spectrometer. These results therefore highlight the sensitivity of the thin-layer sample holders employed in HiPER for spin-labeling studies of biological macromolecules at high fields, where applications can extend to other systems that are facilitated by the modest sample volumes and ease of sample loading and geometry.

  6. Numerical Investigation of Periodically Unsteady Pressure Field in a High Power Centrifugal Diffuser Pump

    Directory of Open Access Journals (Sweden)

    Ji Pei

    2014-05-01

    Full Text Available Pressure fluctuations are the main factors that can give rise to reliability problems in centrifugal pumps. The periodically unsteady pressure characteristics caused by rotor-stator interaction have been investigated by CFD calculation in a residual heat removal pump. Side chamber flow effect is also considered for the simulation to accurately predict the flow in whole flow passage. The pressure fluctuation results in time and frequency domains were considered for several typical monitoring points in impeller and diffuser channels. In addition, the pressure fluctuation intensity coefficient (PFIC based on standard deviation was defined on each grid node for entire space and impeller revolution period. The results show that strong pressure fluctuation intensity can be found in the gap between impeller and diffuser. As a source, the fluctuation can spread to the upstream and downstream flow channels as well as the side chamber channels. Meanwhile, strong pressure fluctuation intensity can be found in the discharge tube of the circular casing. In addition, the obvious influence of operational flow rate on the PFIC distribution can be found. The analysis indicates that the pressure fluctuations in the aspects of both frequency and intensity can be used to comprehensively evaluate the unsteady pressure characteristics in centrifugal pumps.

  7. Numerical investigation of symmetry breaking and critical behavior of the acoustic streaming field in high-intensity discharge lamps

    International Nuclear Information System (INIS)

    Baumann, Bernd; Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2015-01-01

    For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The acoustic streaming effect has been identified as the link between high frequency resonances and low frequency flicker. A highly coupled three-dimensional multiphysics model has been set up to calculate the acoustic streaming velocity field inside the arc tube of high-intensity discharge lamps. It has been found that the velocity field suffers a phase transition to an asymmetrical state at a critical acoustic streaming force. In certain respects the system behaves similar to a ferromagnet near the Curie point. It is discussed how the model allows to investigate the light flicker phenomenon. Concerning computer resources the procedure is considerably less demanding than a direct approach with a transient model. (paper)

  8. Ground vortex flow field investigation

    Science.gov (United States)

    Kuhn, Richard E.; Delfrate, John H.; Eshleman, James E.

    1988-01-01

    Flow field investigations were conducted at the NASA Ames-Dryden Flow Visualization Facility (water tunnel) to investigate the ground effect produced by the impingement of jets from aircraft nozzles on a ground board in a STOL operation. Effects on the overall flow field with both a stationary and a moving ground board were photographed and compared with similar data found in other references. Nozzle jet impingement angles, nozzle and inlet interaction, side-by-side nozzles, nozzles in tandem, and nozzles and inlets mounted on a flat plate model were investigated. Results show that the wall jet that generates the ground effect is unsteady and the boundary between the ground vortex flow field and the free-stream flow is unsteady. Additionally, the forward projection of the ground vortex flow field with a moving ground board is one-third less than that measured over a fixed ground board. Results also showed that inlets did not alter the ground vortex flow field.

  9. HAIC/HIWC field campaign - investigating ice microphysics in high ice water content regions of mesoscale convective systems

    Science.gov (United States)

    Leroy, Delphine; Fontaine, Emmanuel; Schwarzenboeck, Alfons; Strapp, J. Walter; Lilie, Lyle; Dezitter, Fabien; Grandin, Alice

    2015-04-01

    Despite existing research programs focusing on tropical convection, high ice water content (IWC) regions in Mesoscale Convective Systems (MCS) - potentially encountered by commercial aircraft and related to reported in-service events - remain poorly documented either because investigation of such high IWC regions was not of highest priority or because utilized instrumentation was not capable of providing accurate cloud microphysical measurements. To gather quantitative data in high IWC regions, a multi-year international HAIC/HIWC (High Altitude Ice Crystals / High Ice Water Content) field project has been designed including a first field campaign conducted out of Darwin (Australia) in 2014. The French Falcon 20 research aircraft had been equipped among others with a state-of-the-art in situ microphysics package including the IKP (isokinetic evaporator probe which provides a reference measurement of IWC and TWC), the CDP (cloud droplet spectrometer probe measuring particles in the range 2-50 µm), the 2D-S (2D-Stereo, 10-1280 µm) and PIP (precipitation imaging probe, 100-6400 µm) optical array probes. Microphysical data collection has been performed mainly at -40°C and -30°C levels, whereas little data could be sampled at -50°C and at -15C/-10°C. The study presented here focuses on ice crystal size properties, thereby analyzing in detail the 2D image data from 2D-S and PIP optical array imaging probes. 2D images recorded with 2D-S and PIP were processed in order to extract a large variety of geometrical parameters, such as maximum diameter (Dmax), 2D surface equivalent diameter (Deq), and the corresponding number particle size distribution (PSD). Using the PSD information from both probes, a composite size distribution was then built, with sizes ranging from few tens of µm to roughly 10 mm. Finally, mass-size relationships for ice crystals in tropical convection were established in terms of power laws in order to compute median mass diameters MMDmax and

  10. The MAVEN Magnetic Field Investigation

    Science.gov (United States)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2014-01-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a quantization uncertainty of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05%. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers - multiple rotations about the spacecraft x and z axes - to characterize spacecraft fields and/or instrument offsets in flight.

  11. Experimental platform for investigations of high-intensity laser plasma interactions in the magnetic field of a pulsed power generator

    Science.gov (United States)

    Ivanov, V. V.; Maximov, A. V.; Swanson, K. J.; Wong, N. L.; Sarkisov, G. S.; Wiewior, P. P.; Astanovitskiy, A. L.; Covington, A. M.

    2018-03-01

    An experimental platform for the studying of high-intensity laser plasma interactions in strong magnetic fields has been developed based on the 1 MA Zebra pulsed power generator coupled with the 50-TW Leopard laser. The Zebra generator produces 100-300 T longitudinal and transverse magnetic fields with different types of loads. The Leopard laser creates plasma at an intensity of 1019 W/cm2 in the magnetic field of coil loads. Focusing and targeting systems are integrated in the vacuum chamber of the pulsed power generator and protected from the plasma debris and strong mechanical shock. The first experiments with plasma at laser intensity >2 × 1018 W/cm2 demonstrated collimation of the laser produced plasma in the axial magnetic field strength >100 T.

  12. The Juno Magnetic Field Investigation

    Science.gov (United States)

    Connerney, J. E. P.; Benn, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.; Murphy, S.; Odom, J.; Oliversen, R.; Schnurr, R.; Sheppard, D.; Smith, E. J.

    2017-11-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter's planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor suites, each consisting of a tri-axial Fluxgate Magnetometer (FGM) sensor and a pair of co-located imaging sensors mounted on an ultra-stable optical bench. The imaging system sensors are part of a subsystem that provides accurate attitude information (to ˜20 arcsec on a spinning spacecraft) near the point of measurement of the magnetic field. The two sensor suites are accommodated at 10 and 12 m from the body of the spacecraft on a 4 m long magnetometer boom affixed to the outer end of one of 's three solar array assemblies. The magnetometer sensors are controlled by independent and functionally identical electronics boards within the magnetometer electronics package mounted inside Juno's massive radiation shielded vault. The imaging sensors are controlled by a fully hardware redundant electronics package also mounted within the radiation vault. Each magnetometer sensor measures the vector magnetic field with 100 ppm absolute vector accuracy over a wide dynamic range (to 16 Gauss = 1.6 × 106 nT per axis) with a resolution of ˜0.05 nT in the most sensitive dynamic range (±1600 nT per axis). Both magnetometers sample the magnetic field simultaneously at an intrinsic sample rate of 64 vector samples per second. The magnetic field instrumentation may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. The attitude determination system compares images with an on-board star catalog to provide attitude solutions (quaternions) at a rate of up to 4 solutions per second, and may be configured to acquire images of selected targets for science and engineering analysis. The system tracks and catalogs objects that pass through the imager field of

  13. The DYNAMO Orbiter Project: High Resolution Mapping of Gravity/Magnetic Fields and In Situ Investigation of Mars Atmospheric Escape

    Science.gov (United States)

    Smrekar, S.; Chassefiere, E.; Forget, F.; Reme, H.; Mazelle, C.; Blelly, P. -L.; Acuna, M.; Connerney, J.; Purucker, M.; Lin, R.

    2000-01-01

    Dynamo is a small Mars orbiter planned to be launched in 2005 or 2007, in the frame of the NASA/CNES Mars exploration program. It is aimed at improving gravity and magnetic field resolution, in order to better understand the magnetic, geologic and thermal history of Mars, and at characterizing current atmospheric escape, which is still poorly constrained. These objectives are achieved by using a low periapsis orbit, similar to the one used by the Mars Global Surveyor spacecraft during its aerobraking phases. The proposed periapsis altitude for Dynamo of 120-130 km, coupled with the global distribution of periapses to be obtained during one Martian year of operation, through about 5000 low passes, will produce a magnetic/gravity field data set with approximately five times the spatial resolution of MGS. Low periapsis provides a unique opportunity to investigate the chemical and dynamical properties of the deep ionosphere, thermosphere, and the interaction between the atmosphere and the solar wind, therefore atmospheric escape, which may have played a crucial role in removing atmosphere, and water, from the planet. There is much room for debate on the importance of current atmosphere escape processes in the evolution of the Martian atmosphere, as early "exotic" processes including hydrodynamic escape and impact erosion are traditionally invoked to explain the apparent sparse inventory of present-day volatiles. Yet, the combination of low surface gravity and the absence of a substantial internally generated magnetic field have undeniable effects on what we observe today. In addition to the current losses in the forms of Jeans and photochemical escape of neutrals, there are solar wind interaction-related erosion mechanisms because the upper atmosphere is directly exposed to the solar wind. The solar wind related loss rates, while now comparable to those of a modest comet, nonetheless occur continuously, with the intriguing possibility of important cumulative and

  14. Investigating Within-Field Variability of Rice from High Resolution Satellite Imagery in Qixing Farm County, Northeast China

    Directory of Open Access Journals (Sweden)

    Quanying Zhao

    2015-02-01

    Full Text Available Rice is a primary staple food for the world population and there is a strong need to map its cultivation area and monitor its crop status on regional scales. This study was conducted in the Qixing Farm County of the Sanjiang Plain, Northeast China. First, the rice cultivation areas were identified by integrating the remote sensing (RS classification maps from three dates and the Geographic Information System (GIS data obtained from a local agency. Specifically, three FORMOSAT-2 (FS-2 images captured during the growing season in 2009 and a GIS topographic map were combined using a knowledge-based classification method. A highly accurate classification map (overall accuracy = 91.6% was generated based on this Multi-Data-Approach (MDA. Secondly, measured agronomic variables that include biomass, leaf area index (LAI, plant nitrogen (N concentration and plant N uptake were correlated with the date-specific FS-2 image spectra using stepwise multiple linear regression models. The best model validation results with a relative error (RE of 8.9% were found in the biomass regression model at the phenological stage of heading. The best index of agreement (IA value of 0.85 with an RE of 13.6% was found in the LAI model, also at the heading stage. For plant N uptake estimation, the most accurate model was again achieved at the heading stage with an RE of 11% and an IA value of 0.77; however, for plant N concentration estimation, the model performance was best at the booting stage. Finally, the regression models were applied to the identified rice areas to map the within-field variability of the four agronomic variables at different growth stages for the Qixing Farm County. The results provide detailed spatial information on the within-field variability on a regional scale, which is critical for effective field management in precision agriculture.

  15. Investigation of the dipole response of nickel isotopes in the presence of a high-frequency electromagnetic field

    International Nuclear Information System (INIS)

    Rossi, Dominic M.

    2010-01-01

    The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of 56-57 Ni and 67-72 Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm 2 Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich 67-69 Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the (γ,n) and (γ,2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable 58 Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured (γ,n) and (γ,np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of 67-69 Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the χ 2 minimization of the model GDR to the measured data of the (γ,2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the total measured E1 strength provides the low-lying E1 strength

  16. An account of the discrepancy between MRI and PET cerebral blood flow measures. A high-field MRI investigation.

    Science.gov (United States)

    Donahue, Manus J; Lu, Hanzhang; Jones, Craig K; Pekar, James J; van Zijl, Peter C M

    2006-12-01

    There is controversy concerning the discrepancy between absolute cerebral blood flow (CBF) values measured using positron emission tomography (PET) and magnetic resonance imaging (MRI). To gain insight into this problem, the increased signal-to-noise ratio (SNR) and extended T(1) relaxation times of blood and tissue at 3.0 T were exploited to perform pulsed arterial spin labeling (PASL) MRI measurements as a function of spatial resolution and post-labeling delay. The results indicate that, when using post-labeling delays shorter than 1500 ms, MRI gray matter flow values may become as high as several times the correct CBF values owing to tissue signal contamination by remaining arterial blood water label. For delays above 1500 ms, regional PASL-based CBF values (n = 5; frontal gray matter: 48.8 +/- 3.3(SD) ml/100 g/min; occipital gray matter: 49.3 +/- 4.5 ml/100 g/min) comparable with PET-based measurements can be obtained by using spatial resolutions comparable with PET (5-7.5 mm in-plane). At very high resolution (2.5 x 2.5 x 3 mm(3)), gray matter CBF values were found to increase by 10-20%, a consequence attributed to reduction in partial volume effects with cerebrospinal fluid and white matter. The recent availability of MRI field strengths of 3.0 T and higher will facilitate the use of MRI-based CBF measurements in the clinic. Copyright (c) 2006 John Wiley & Sons, Ltd.

  17. Investigation of the dipole response of nickel isotopes in the presence of a high-frequency electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Dominic M.

    2010-01-25

    The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of {sup 56-57}Ni and {sup 67-72}Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm{sup 2} Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich {sup 67-69}Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the ({gamma},n) and ({gamma},2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable {sup 58}Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured ({gamma},n) and ({gamma},np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of {sup 67-69}Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the {chi}{sup 2} minimization of the model GDR to the measured data of the ({gamma},2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the

  18. Numerical investigation of the high Reynolds number 3D flow field generated by a self-propelling manta ray

    Science.gov (United States)

    Pederzani, Jean-Noel; Haj-Hariri, Hossein

    2012-11-01

    An embedded-boundary (or cut-cell) method for complex geometry with moving boundaries is used to solve the three dimensional Navier-Stokes equation around a self-propelling manta swimming at moderately high Reynolds numbers. The motion of the ray is prescribed using a kinematic model fitted to actual biological data. The dependence of thrust production mechanism on Strouhal and Reynolds numbers is investigated. The vortex core structures are accurately plotted and a correlation between wake structures and propulsive performance is established. This insight is critical in understanding the key flow features that a bio-inspired autonomous vehicle should reproduce in order to swim efficiently. The solution method is implemented, on a block-structured Cartesian grid using a cut-cell approach enabling the code to correctly evaluate the wall shear-stress, a key feature necessary at higher Reynolds. To enhance computational efficiency, a parallel adaptive mesh refinement technique is used. The present method is validated against published experimental results. Supported by ONR MURI.

  19. Investigations on the magnetic field coupling of automotive high voltage systems to determine relevant parameters for an EMR-optimized designing

    Science.gov (United States)

    Krause, David; John, Werner; Weigel, Robert

    2016-03-01

    The implementation of electrical drive trains in modern vehicles is a new challenge for EMC development. This contribution depicts a variety of investigations on magnetic field coupling of automotive high-voltage (HV) systems in order to fulfil the requirements of an EMR-optimized designing. The theoretical background is discussed within the scope of current analysis, including the determination of current paths and spectral behaviour. It furthermore presents models of shielded HV cables with particular focus on the magnetic shielding efficiency. Derived findings are validated by experimental measurements of a state-of-the-art demonstrator on system level. Finally EMC design rules are discussed in the context of minimized magnetic fields.

  20. Investigation of linearity of the ITER outer vessel steady-state magnetic field sensors at high temperature.

    Czech Academy of Sciences Publication Activity Database

    Entler, Slavomír; Ďuran, Ivan; Kocan, M.; Vayakis, G.

    2017-01-01

    Roč. 12, č. 7 (2017), č. článku C07007. ISSN 1748-0221. [European Conference on Plasma Diagnostics (ECPD2017)/2./. Bordeaux, 18.04.2017-21.04.2017] EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : Plasma diagnostics - probes * Detector alignment and calibration methods (lasers, sources, particle-beams) * ITER * Magnetic field Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/12/07/C07007/pdf

  1. High-mast light poles anchor nut loosening in Alaska : an investigation of field monitoring and finite-element analysis.

    Science.gov (United States)

    2014-09-01

    High mast lighting poles (HMLPs) are tall, roadside structures effective for lighting large areas of highways and intersections. The Alaska Department of Transportation : and Public Facilities (AKDOT&PF) maintains 118 such poles in the greater Anchor...

  2. High field electron linacs

    International Nuclear Information System (INIS)

    Le Duff, J.

    1985-12-01

    High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

  3. Investigation of anchor nut loosening in high-mast light poles using field monitoring and finite element analysis.

    Science.gov (United States)

    2014-09-01

    High mast lighting poles (HMLPs) are cost effective structures for lighting highways and intersections. They are 100 to 250 feet (30m to 76m) tall, and can hold a variety of lamp configurations. They are : commonly used at highway interchanges becaus...

  4. Investigating in-field and out-of-field neutron contamination in high-energy medical linear accelerators based on the treatment factors of field size, depth, beam modifiers, and beam type.

    Science.gov (United States)

    Biltekin, Fatih; Yeginer, Mete; Ozyigit, Gokhan

    2015-07-01

    We analysed the effects of field size, depth, beam modifier and beam type on the amount of in-field and out-of-field neutron contamination for medical linear accelerators (linacs). Measurements were carried out for three high-energy medical linacs of Elekta Synergy Platform, Varian Clinac DHX High Performance and Philips SL25 using bubble detectors. The photo-neutron measurements were taken in the first two linacs with 18 MV nominal energy, whereas the electro-neutrons were measured in the three linacs with 9 MeV, 10 MeV, 15 MeV and 18 MeV. The central neutron doses increased with larger field sizes as a dramatic drop off was observed in peripheral areas. Comparing with the jaws-shaped open-field of 10 × 10 cm, the motorised and physical wedges contributed to neutron contamination at central axis by 60% and 18%, respectively. The similar dose increment was observed in MLC-shaped fields. The contributions of MLCs were in the range of 55-59% and 19-22% in Elekta and Varian linacs comparing with 10 × 10 and 20 × 20 cm open fields shaped by the jaws, respectively. The neutron doses at shallow depths were found to be higher than the doses found at deeper regions. The electro-neutron dose at the 18 MeV energy was higher than the doses at the electron energies of 15 MeV and 9 MeV by a factor of 3 and 50, respectively. The photo- and electro-neutron dose should be taken into consideration in the radiation treatment with high photon and electron energies. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. Time-resolved investigation of dual high power impulse magnetron sputtering with closed magnetic field during deposition of Ti-Cu thin films

    International Nuclear Information System (INIS)

    Stranak, Vitezslav; Hippler, Rainer; Cada, Martin; Hubicka, Zdenek; Tichy, Milan

    2010-01-01

    Time-resolved comparative study of dual magnetron sputtering (dual-MS) and dual high power impulse magnetron sputtering (dual-HiPIMS) systems arranged with closed magnetic field is presented. The dual-MS system was operated with a repetition frequency 4.65 kHz (duty cycle ≅50%). The frequency during dual-HiPIMS is lower as well as its duty cycle (f=100 Hz, duty 1%). Different metallic targets (Ti, Cu) and different cathode voltages were applied to get required stoichiometry of Ti-Cu thin films. The plasma parameters of the interspace between magnetrons in the substrate position were investigated by time-resolved optical emission spectroscopy, Langmuir probe technique, and measurement of ion fluxes to the substrate. It is shown that plasma density as well as ion flux is higher about two orders of magnitude in dual-HiPIMS system. This fact is partially caused by low diffusion of ionized sputtered particles (Ti + ,Cu + ) which creates a preionized medium.

  6. Probing the Interaction of Human Serum Albumin with Norfloxacin in the Presence of High-Frequency Electromagnetic Fields: Fluorescence Spectroscopy and Circular Dichroism Investigations

    Directory of Open Access Journals (Sweden)

    Jamshidkhan Chamani

    2011-11-01

    Full Text Available The present study describes an investigation by fluorescence quenching, circular dichroism and UV-visible spectroscopy of the interaction between norfloxacin (NRF and human serum albumin (HSA in the presence of electromagnetic fields (EMFs. The results obtained from this study indicated that NRF had a strong ability to quench HSA at λex = 280 nm. In addition, a slight blue shift occurred, which suggested that the microenvironment of the protein became more hydrophobic after addition of NRF. The interaction between the NRF and HSA, whether in the absence or presence of an EMF, was considered to be a static quenching mechanism. Moreover, synchronous fluorescence demonstrated that the microenvironment around Trp became modified. Data of HSA-NRF in the presence of EMFs between 1 Hz–1 MHz confirmed the results of quenching and blue shifts. Corresponding Stern-Volmer plots were also drawn and the resultant Ksv and kq values were compared. Moreover, the binding parameters, including the number of binding sites, the binding constant and the distance, r, between donor and acceptor, were calculated based on Förster’s non-radiative energy transfer theory. According to far and near UV-CD, the formation of the complex caused changes of the secondary and tertiary structures of HSA. The obtained results are significant for patients who are subjected to high-frequency radiation as this was found to reduce the affinity of NRF to HSA.

  7. Correlative Analysis of Vertebral Trabecular Bone Microarchitecture and Mechanical Properties: A Combined Ultra-high Field (7 Tesla) MRI and Biomechanical Investigation.

    Science.gov (United States)

    Guenoun, Daphne; Fouré, Alexandre; Pithioux, Martine; Guis, Sandrine; Le Corroller, Thomas; Mattei, Jean-Pierre; Pauly, Vanessa; Guye, Maxime; Bernard, Monique; Chabrand, Patrick; Champsaur, Pierre; Bendahan, David

    2017-10-15

    High-resolution imaging and biomechanical investigation of ex-vivo vertebrae. The aim of this study was to assess bone microarchitecture of cadaveric vertebrae using ultra-high field (UHF) 7 Tesla magnetic resonance imaging (MRI) and to determine whether the corresponding microarchitecture parameters were related to bone mineral density (BMD) and bone strength assessed by dual-energy x-ray absorptiometry (DXA) and mechanical compression tests. Limitations of DXA for the assessment of bone fragility and osteoporosis have been recognized and criteria of microarchitecture alteration have been included in the definition of osteoporosis. Although vertebral fracture is the most common osteoporotic fracture, no study has assessed directly vertebral trabecular bone microarchitecture. BMD of 24 vertebrae (L2, L3, L4) from eight cadavers was investigated using DXA. The bone volume fraction (BVF), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) of each vertebra were quantified using UHF MRI. Measurements were performed by two operators to characterize the inter-rater reliability. The whole set of specimens underwent mechanical compression tests to failure and the corresponding failure stress was calculated. The inter-rater reliability for bone microarchitecture parameters was good with intraclass correlation coefficients ranging from 0.82 to 0.94. Failure load and stress were significantly correlated with BVF, Tb.Sp, and BMD (P < 0.05). Tb.Th was only correlated with the failure stress (P < 0.05). Multiple regression analysis demonstrated that the combination of BVF and BMD improved the prediction of the failure stress from an adjusted R = 0.384 for BMD alone to an adjusted R = 0.414. We demonstrated for the first time that the vertebral bone microarchitecture assessed with UHF MRI was significantly correlated with biomechanical parameters. Our data suggest that the multimodal assessment of BMD and trabecular bone microarchitecture with UHF MRI

  8. The ARASE (ERG) magnetic field investigation

    Science.gov (United States)

    Matsuoka, Ayako; Teramoto, Mariko; Nomura, Reiko; Nosé, Masahito; Fujimoto, Akiko; Tanaka, Yoshimasa; Shinohara, Manabu; Nagatsuma, Tsutomu; Shiokawa, Kazuo; Obana, Yuki; Miyoshi, Yoshizumi; Mita, Makoto; Takashima, Takeshi; Shinohara, Iku

    2018-03-01

    The fluxgate magnetometer for the Arase (ERG) spacecraft mission was built to investigate particle acceleration processes in the inner magnetosphere. Precise measurements of the field intensity and direction are essential in studying the motion of particles, the properties of waves interacting with the particles, and magnetic field variations induced by electric currents. By observing temporal field variations, we will more deeply understand magnetohydrodynamic and electromagnetic ion-cyclotron waves in the ultra-low-frequency range, which can cause production and loss of relativistic electrons and ring-current particles. The hardware and software designs of the Magnetic Field Experiment (MGF) were optimized to meet the requirements for studying these phenomena. The MGF makes measurements at a sampling rate of 256 vectors/s, and the data are averaged onboard to fit the telemetry budget. The magnetometer switches the dynamic range between ± 8000 and ± 60,000 nT, depending on the local magnetic field intensity. The experiment is calibrated by preflight tests and through analysis of in-orbit data. MGF data are edited into files with a common data file format, archived on a data server, and made available to the science community. Magnetic field observation by the MGF will significantly improve our knowledge of the growth and decay of radiation belts and ring currents, as well as the dynamics of geospace storms.

  9. High-frequency and -field EPR investigation of a manganese(III) N-confused porphyrin complex, [Mn(NCTPP)(py)2].

    Science.gov (United States)

    Harvey, John D; Ziegler, Christopher J; Telser, Joshua; Ozarowski, Andrew; Krzystek, J

    2005-06-27

    We report the first high-frequency and -field electron paramagnetic resonance (HFEPR) study of a Mn(III) N-confused porphyrin (NCP) complex (NCP is also known as inverted porphyrin or 2-aza-21-carbaporphyrin). We have found a striking variation in the electronic properties of the S = 2 Mn(III) ion coordinated by NCP compared to other Mn(III) porphyrinoid complexes. Thus, inversion of a single pyrrole ring greatly changes the equatorial ligand field exerted and leads to large magnitudes of both the axial and rhombic zero-field splitting [respectively, D = -3.084(3) cm(-1), E = -0.608(3) cm(-1)], which are unprecedented in other Mn(III) porphyrinoids.

  10. The robustness of high-Tc superconductivity in underdoped YBa2Cu3O6+x investigated in under strong magnetic fields

    Science.gov (United States)

    Harrison, Neil; Hsu, Y.-T.; Hartstein, M.; Chan, M.; Porras, J.; Loew, T.; Le Tacon, M.; Lonzarich, G.; Keimer, B.; Flux, V.; Sebastian, S.

    A central unresolved mystery in high-Tc superconductivity is whether the pairing amplitude is small in the underdoped regime and relates to the superfluid density or whether it is large and relate to the intrinsic energy scales of the Mott insulating parent state. The magnetic field provides a sensitive probe of the pairing amplitude. However, experimental probes of the extent of the vortex state in temperature and magnetic field have thus far been indirect and hence subject to debate. Here we report measurements over a broad range of temperature and magnetic fields which we use to probe the extent of the vortex region in underdoped YBa2Cu3O6+x. and its interplay with quantum oscillations. N.H. acknowledges UU DOE BES Support for ''Science of 100 Tesla''.

  11. INVESTIGATION OF ELECTROMAGNETIC FIELDS IN RESIDENTIAL AREAS

    Directory of Open Access Journals (Sweden)

    Dušan MEDVEĎ

    2017-09-01

    Full Text Available This article is devoted to investigation of impact of electromagnetic fields around the electrical equipment used in a residential area and their impact on the human body. This paper was based on sets of measurements of magnetic induction B with magnetometer and on computational simulations in ANSYS for particular appliances often used in household. The results from measurements and simulations led to setting out the recommendations for practical action in the form of elimination of harmful electromagnetic radiation.

  12. Highly excited atom in the electromagnetic field

    International Nuclear Information System (INIS)

    Delone, N.B.; Krajnov, V.P.; Shepelyanskij, D.L.; AN SSSR, Novosibirsk. Inst. Yadernoj Fiziki)

    1983-01-01

    Properties of highly excited atom placed in electromagnetic field are reviewed. Probabilities of bound-boUnd and bound-free transition between quasi-classical atomic states, as well approximate rules of selection for such transitions, are considered. Properties of dynamic polarization of highly excited atomic states are investigated. Quantum mechanisms of ionization (multiphoton and tunnel) of highly excited states are discussed. A considerable part of the review is devoted to the consideration of the stochastic dynamics of the classic atomic electron in the variable monochromatic electromagnetic field. Threshold values of field intensity for the appearance of stochastic electron motion and atom ionization depending on field frequency, its polarization and the main quantum number of the atomic state considered are presented. The effect of the orbital moment of the ionized state on the process of stochasticity appearance is discussed. In the framework of classical mechanics and quasiclassical approximation of quantum mechanics the classical diffusion ionization of highly excited atom in electromagnetic field is considered. The problem on the application of classical mechanics in the investigation of properties of highly excited atom in electromagnetic field is discussed. Conditions for the realization of quantum and quasiclassic ionization of highly excited atoms are considered. In the last part of the review experimental data on the behaviour of highly excited atoms in the field of radiofrequency range are analyzed. The comparison of the data of experiments and those of the theory given in the revieW deronstrate their good agreement

  13. Long-term exposure to electric fields. A cross-sectional epidemiologic investigation of occupationally exposed workers in high-voltage substations.

    Science.gov (United States)

    Knave, B; Gamberale, F; Bergström, S; Birke, E; Iregren, A; Kolmodin-Hedman, B; Wennberg, A

    1979-06-01

    In the present epidemiologic study, 53 workers with a long-term (more than five years) exposure to the electric field of 400 kV substations were examined and compared with a matched reference group of 53 nonexposed workers from the same power companies. Matching variables included age, geographic location and employment time. The aim of the study was to investigate the possibility of persistent, chronic health effects in the exposed group as a consequence of exposure. The investigation indluded the nervous system (neurasthenic symptoms, psychological tests, electroencephalography), the cardiovascular system (symptoms, blood pressure, electrocardiography), and the blood (hemoglobin, red blood cells, reticulocytes, white blood cells including differential count, thrombocytes, sedimentation rate). Fertility was also assessed. The results showed no differences between the exposed and reference groups as a consequence of the long-term exposure to the electric fields. The groups differed, however, in that the exposed group had (a) consistently better results on the psychological performance tests, (b) a fewer number of children, especially boys, and (c) somewhat higher education. The differences in test results were due to the higher education among the exposed. The difference in number of children was also thought to be related to factors other than exposure since it was found to be present already 10--15 years before the work in 400 kV substations began.

  14. A modular designed ultra-high-vacuum spin-polarized scanning tunneling microscope with controllable magnetic fields for investigating epitaxial thin films.

    Science.gov (United States)

    Wang, Kangkang; Lin, Wenzhi; Chinchore, Abhijit V; Liu, Yinghao; Smith, Arthur R

    2011-05-01

    A room-temperature ultra-high-vacuum scanning tunneling microscope for in situ scanning freshly grown epitaxial films has been developed. The core unit of the microscope, which consists of critical components including scanner and approach motors, is modular designed. This enables easy adaptation of the same microscope units to new growth systems with different sample-transfer geometries. Furthermore the core unit is designed to be fully compatible with cryogenic temperatures and high magnetic field operations. A double-stage spring suspension system with eddy current damping has been implemented to achieve ≤5 pm z stability in a noisy environment and in the presence of an interconnected growth chamber. Both tips and samples can be quickly exchanged in situ; also a tunable external magnetic field can be introduced using a transferable permanent magnet shuttle. This allows spin-polarized tunneling with magnetically coated tips. The performance of this microscope is demonstrated by atomic-resolution imaging of surface reconstructions on wide band-gap GaN surfaces and spin-resolved experiments on antiferromagnetic Mn(3)N(2)(010) surfaces.

  15. High-frequency and -field EPR spectroscopy of tris(2,4-pentanedionato)manganese(III): investigation of solid-state versus solution Jahn-Teller effects.

    Science.gov (United States)

    Krzystek, J; Yeagle, Gregory J; Park, Ju-Hyun; Britt, R David; Meisel, Mark W; Brunel, Louis-Claude; Telser, Joshua

    2003-07-28

    High-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy of a classical coordination complex, Mn(acac)(3) (Hacac = 2,4-pentanedione), has been performed on both solid powder and frozen solution (in CH(2)Cl(2)/toluene, 3:2 v/v) samples. Parallel mode detection X-band EPR spectra exhibiting resolved (55)Mn hyperfine coupling were additionally obtained for frozen solutions. Magnetic susceptibility and field-dependent magnetization measurements were also made on powder samples. Analysis of the entire EPR data set for the frozen solution allowed extraction of the relevant spin Hamiltonian parameters: D = -4.52(2); |E| = 0.25(2) cm(-1); g(iso) = 1.99(1). The somewhat lower quality solid-state HFEPR data and the magnetic measurements confirmed these parameters. These parameters are compared to those for other complexes of Mn(III) and to previous studies on Mn(acac)(3) using X-ray crystallography, solution electronic absorption spectroscopy, and powder magnetic susceptibility. Crystal structures have been reported for Mn(acac)(3) and show tetragonal distortion, as expected for this Jahn-Teller ion (Mn(3+), 3d(4)). However, in one case, the molecule exhibits axial compression and, in another, axial elongation. The current HFEPR studies clearly show the negative sign of D, which corresponds to an axial (tetragonal) elongation in frozen solution. The correspondence among solution and solid-state HFEPR data, solid-state magnetic measurements, and an HFEPR study by others on a related complex indicates that the form of Mn(acac)(3) studied here exhibits axial elongation in all cases. Such tetragonal elongation has been found for Mn(3+) and Cr(2+) complexes with homoleptic pseudooctahedral geometry as well as for Mn(3+) in square pyramidal geometry. This taken together with the results obtained here for Mn(acac)(3) in frozen solution indicates that axial elongation could be considered the "natural" form of Jahn-Teller distortion for octahedral high-spin 3d(4

  16. High Field Atherosclerotic Plaque MRI

    OpenAIRE

    Yuan, Chun; Wang, Jinnan; Balu, Niranjan

    2012-01-01

    Manifestations of atherosclerotic plaque in different arterial beds range from perfusion deficits to overt ischemia such as stroke and myocardial infarction. Atherosclerotic plaque composition is known to be associated with its propensity to rupture and cause vascular events. MRI of atherosclerotic plaque using clinical 1.5T scanners can detect plaque composition. Plaque MRI at higher field strengths offers both opportunities and challenges to improving the high spatial-resolution and contras...

  17. Strain sensors for high field pulse magnets

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Christian [Los Alamos National Laboratory; Zheng, Yan [Los Alamos National Laboratory; Easton, Daniel [Los Alamos National Laboratory; Farinholt, Kevin M [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory

    2009-01-01

    In this paper we present an investigation into several strain sensing technologies that are being considered to monitor mechanical deformation within the steel reinforcement shells used in high field pulsed magnets. Such systems generally operate at cryogenic temperatures to mitigate heating issues that are inherent in the coils of nondestructive, high field pulsed magnets. The objective of this preliminary study is to characterize the performance of various strain sensing technologies at liquid nitrogen temperatures (-196 C). Four sensor types are considered in this investigation: fiber Bragg gratings (FBG), resistive foil strain gauges (RFSG), piezoelectric polymers (PVDF), and piezoceramics (PZT). Three operational conditions are considered for each sensor: bond integrity, sensitivity as a function of temperature, and thermal cycling effects. Several experiments were conducted as part of this study, investigating adhesion with various substrate materials (stainless steel, aluminum, and carbon fiber), sensitivity to static (FBG and RFSG) and dynamic (RFSG, PVDF and PZT) load conditions, and sensor diagnostics using PZT sensors. This work has been conducted in collaboration with the National High Magnetic Field Laboratory (NHMFL), and the results of this study will be used to identify the set of sensing technologies that would be best suited for integration within high field pulsed magnets at the NHMFL facility.

  18. FIELD INVESTIGATION OF THE DRIFT SHADOW

    International Nuclear Information System (INIS)

    G.W. Su; T.J. Kneafsey

    2006-01-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rock mass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming the existence of the drift shadow have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow--and the corresponding hydrological process at the Hazel-Atlas silica-sand mine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rock mass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content using a gravimetric technique, as well as analyzed for chemistry. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift

  19. Field investigation of the drift shadow

    International Nuclear Information System (INIS)

    Su, Grace W.; Kneafsey, Timothy J.; Ghezzehei, Teamrat A.; Marshall, Brian D.; Cook, Paul J.

    2005-01-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rockmass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming its existence have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow and the corresponding hydrological process at the Hazel-Atlas silica-sandmine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine Formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rockmass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content and chemical constituents. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift. Tensiometers, electrical resistance probes, neutron probes, and ground

  20. Federal Bureau of Investigation (FBI) Field Office Jurisdiction/Divisions

    Data.gov (United States)

    Department of Homeland Security — This dataset represents the FBI (Federal Bureau of Investigations) national field office jurisdiction/divisional boundary locations. The field offices are centrally...

  1. Experimental investigation of strong field trident production

    NARCIS (Netherlands)

    Esberg, J.; Kirsebom, K.; Knudsen, H.; Thomsen, H.D.; Uggerhøj, E.; Uggerhøj, U.I.; Sona, P.; Mangiarotti, A.; Ketel, T.J.; Ditzdar, A.; Dalton, M.M.; Ballestrero, S.; Connell, S.H.

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single

  2. Cellulose Structural Polymorphism in Plant Primary Cell Walls Investigated by High-Field 2D Solid-State NMR Spectroscopy and Density Functional Theory Calculations.

    Science.gov (United States)

    Wang, Tuo; Yang, Hui; Kubicki, James D; Hong, Mei

    2016-06-13

    The native cellulose of bacterial, algal, and animal origins has been well studied structurally using X-ray and neutron diffraction and solid-state NMR spectroscopy, and is known to consist of varying proportions of two allomorphs, Iα and Iβ, which differ in hydrogen bonding, chain packing, and local conformation. In comparison, cellulose structure in plant primary cell walls is much less understood because plant cellulose has lower crystallinity and extensive interactions with matrix polysaccharides. Here we have combined two-dimensional magic-angle-spinning (MAS) solid-state nuclear magnetic resonance (solid-state NMR) spectroscopy at high magnetic fields with density functional theory (DFT) calculations to obtain detailed information about the structural polymorphism and spatial distributions of plant primary-wall cellulose. 2D (13)C-(13)C correlation spectra of uniformly (13)C-labeled cell walls of several model plants resolved seven sets of cellulose chemical shifts. Among these, five sets (denoted a-e) belong to cellulose in the interior of the microfibril while two sets (f and g) can be assigned to surface cellulose. Importantly, most of the interior cellulose (13)C chemical shifts differ significantly from the (13)C chemical shifts of the Iα and Iβ allomorphs, indicating that plant primary-wall cellulose has different conformations, packing, and hydrogen bonding from celluloses of other organisms. 2D (13)C-(13)C correlation experiments with long mixing times and with water polarization transfer revealed the spatial distributions and matrix-polysaccharide interactions of these cellulose structures. Celluloses f and g are well mixed chains on the microfibril surface, celluloses a and b are interior chains that are in molecular contact with the surface chains, while cellulose c resides in the core of the microfibril, outside spin diffusion contact with the surface. Interestingly, cellulose d, whose chemical shifts differ most significantly from those of

  3. Experimental investigation of strong field trident production

    CERN Document Server

    Esberg, J; Knudsen, H; Thomsen, H D; Uggerhøj, E; Uggerhøj, U I; Sona, P; Mangiarotti, A; Ketel, T J; Dizdar, A; Dalton, M M; Ballestrero, S; Connell, S H

    2010-01-01

    We show by experiment that an electron impinging on an electric field that is of critical magnitude in its rest frame, may produce an electron-positron pair. Our measurements address higher-order QED, using the strong electric fields obtainable along particular crystallographic directions in single crystals. For the amorphous material our data are in good agreement with theory, whereas a discrepancy with theory on the magnitude of the trident enhancement is found in the precisely aligned case where the strong electric field acts.

  4. NUMERICAL MODELING AND INVESTIGATION OF CONTACT FRICTION INFLUENCE ON THERMAL FIELDS DISTRIBUTION AND DEFLECTED MODE IN STEEL WIRE AT HIGH-SPEED WIRE DRAWING

    Directory of Open Access Journals (Sweden)

    M. N. Vereshchagin

    2009-01-01

    Full Text Available The appraisal of  character of  the temperature fields distribution in dies at their interactions in the processes of  wire drawing in dependence on contact friction in conditions of  the system wire-die is given.

  5. Hyperfine structure and magnetic properties of Zn doped Co{sub 2}Z hexaferrite investigated by high-field Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jung Tae; Kim, Chul Sung, E-mail: cskim@kookmin.ac.kr [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of)

    2015-05-07

    The polycrystalline samples of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0, 1.5, and 2.0) were synthesized by the standard solid-state-reaction method. Based on the XRD patterns analyzed by Rietveld refinement, the structure was determined to be single-phased hexagonal with space group of P6{sub 3}/mmc. With increasing Zn ion concentration, the unit cell volume (V{sub u}) of samples was increased, as the sites of Fe{sup 3+} ions changed from tetrahedral to octahedral sites. We have obtained zero-field Mössbauer spectra of all samples at various temperatures ranging from 4.2 to 750 K. The measured spectra below T{sub C} were analyzed with six distinguishable sextets due to the superposition of ten-sextets for Fe sites, corresponding to the Z-type hexagonal ferrite. Also, the hyperfine field (H{sub hf}) and electric quadrupole shift (E{sub Q}) have shown abrupt changes around spin transition temperature (T{sub S}). In addition, Mössbauer spectra of all samples at 4.2 K were taken with an applied field ranging from 0 to 50 kOe, which indicates the decrease in the canting angle between applied field and H{sub hf} of samples with increasing Zn concentration.

  6. Field and laboratory investigation of photocatalytic pavements.

    Science.gov (United States)

    2011-11-01

    "In spite of the importance of the national transportation network, there is a growing recognition that highway operations have major environmental impacts during construction and service. High traffic volumes cause high concentration of nitrogen oxi...

  7. Numerical Investigation of unsteady inlet flow fields

    Science.gov (United States)

    Hsieh, T.; Wardlaw, A. B., Jr.; Collins, P.; Coakley, T.

    1984-01-01

    The flow field within an unsteady, two-dimensional inlet is studied numerically, using a two dimensional Navier Stokes and a one-dimensional inviscid model. Unsteadiness is introduced by varying the outflow pressure boundary condition. The cases considered include outflow pressure variations which were a single pressure pulse, a rapid increase and a sine function. The amplitude of the imposed exit plane pressure disturbance varied between 1 percent and 20 percent of the mean exit pressure. At the higher levels of pressure fluctuation, the viscous flow field results bore little resemblance to the inviscid ones. The viscous solution included such phenomena as shock trains and bifurcating separation pockets. The induced velocity at the outflow plane predicted by the viscous model differs significantly from accoustical theory or small perturbation results.

  8. Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting tapes in a split-pair 15 T horizontal magnet

    International Nuclear Information System (INIS)

    Sunwong, P.; Higgins, J. S.; Hampshire, D. P.

    2014-01-01

    We present the designs of probes for making critical current density (J c ) measurements on anisotropic high-temperature superconducting tapes as a function of field, field orientation, temperature and strain in our 40 mm bore, split-pair 15 T horizontal magnet. Emphasis is placed on the design of three components: the vapour-cooled current leads, the variable temperature enclosure, and the springboard-shaped bending beam sample holder. The vapour-cooled brass critical-current leads used superconducting tapes and in operation ran hot with a duty cycle (D) of ∼0.2. This work provides formulae for optimising cryogenic consumption and calculating cryogenic boil-off, associated with current leads used to make J c measurements, made by uniformly ramping the current up to a maximum current (I max ) and then reducing the current very quickly to zero. They include consideration of the effects of duty cycle, static helium boil-off from the magnet and Dewar (b ′ ), and the maximum safe temperature for the critical-current leads (T max ). Our optimized critical-current leads have a boil-off that is about 30% less than leads optimized for magnet operation at the same maximum current. Numerical calculations show that the optimum cross-sectional area (A) for each current lead can be parameterized by LI max /A=[1.46D −0.18 L 0.4 (T max −300) 0.25D −0.09 +750(b ′ /I max )D 10 −3 I max −2.87b ′ ]× 10 6 A m −1 where L is the current lead's length and the current lead is operated in liquid helium. An optimum A of 132 mm 2 is obtained when I max = 1000 A, T max = 400 K, D = 0.2, b ′ = 0.3 l h −1 and L = 1.0 m. The optimized helium consumption was found to be 0.7 l h −1 . When the static boil-off is small, optimized leads have a boil-off that can be roughly parameterized by: b/I max  ≈ (1.35 × 10 −3 )D 0.41 l h ‑1  A −1 . A split-current-lead design is employed to minimize the rotation of the probes during the high current measurements in

  9. EIS Field Investigation in an Archaeological Site

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    and metal objects. The area has been anaerobic and the corrosion rate has been very low for the metal objects to be preserved for so long, but it is now a major concern, whether the artefacts will further on be preserved in the area or will now corrode away. The National Museum is now monitoring...... measurements, electrical resistance corrosion rate measurements and weight loss data from the initial 15 months exposure will be presented and discussed as well as some practical aspects of field monitoring....

  10. Investigation of an angular spectrum approach for pulsed ultrasound fields

    DEFF Research Database (Denmark)

    Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

    2013-01-01

    An Angular Spectrum Approach (ASA)is formulated and employed to simulate linear pulsed ultra sound fields for high bandwidth signals. Ageometrically focused piston transducer is used as the acoustic source. Signals are cross-correlated to findthe true sound speed during the measurement to make...... the simulated and measured pulses in phase for comparisons. The calculated sound speed in the measurement is varied between 1487.45 m/s and 1487.75 m/s by using different initial values in the ASA simulation. Results from the pulsed ASA simulation susing both Field II simulated and hydrophone measured acoustic...... sources are compared to the Field II simulated and hydroph one measure dpulses, respectively. The total relative root mean squar e(RMS)errors of the pulsed ASA are investigated by using different time-point, zero-padding factors, spatial sampling interval and temporal sampling frequency in the sim ulation...

  11. Investigation of Silica-Supported Vanadium Oxide Catalysts by High-Field 51 V Magic-Angle Spinning NMR

    Energy Technology Data Exchange (ETDEWEB)

    Jaegers, Nicholas R.; Wan, Chuan; Hu, Mary Y.; Vasiliu, Monica; Dixon, David A.; Walter, Eric; Wachs, Israel E.; Wang, Yong; Hu, Jian Zhi

    2017-03-14

    Supported V2O5/SiO2 catalysts were studied using solid state 51V MAS NMR at a sample spinning rate of 36 kHz and at a magnetic field of 19.975 T for a better understanding of the coordination of the vanadium oxide as a function of environmental conditions . Structural transformations of the supported vanadium oxide species between the catalyst in the dehydrated state and hydrated state under an ambient environment were revisited to examine the degree of oligomerization and the effect of water. The experimental results indicate the existence of a single dehydrated surface vanadium oxide species that resonates at -675 ppm and two vanadium oxide species under ambient conditions that resonate at -566 and -610 ppm, respectively. No detectable structural difference was found as a function of vanadium oxide loading on SiO2 (3% V2O5/SiO2 and 8% V2O5/SiO2). Quantum chemistry simulations of the 51V NMR chemical shifts on predicted surface structures were used as an aide in understanding potential surface vanadium oxide species on the silica support. The results suggest the formation of isolated surface VO4 units for the dehydrated catalysts with the possibility of dimer and cyclic trimer presence. The absence of bridging V-O-V vibrations (~200-300 cm-1) in the Raman spectra [Gao et al. J. Phys. Chem. B 1998, 102, 10842-10852], however, indicates that the isolated surface VO4 sites are the dominant dehydrated surface vanadia species on silica. Upon exposure to water, hydrolysis of the bridging V-O-Si bonds is most likely responsible for the decreased electron shielding experienced by vanadium. No indicators for the presence of hydrated decavanadate clusters or hydrated vanadia gels previously proposed in the literature were detected in this study.

  12. High-field EPR investigations of Mn(III)Mn(IV) and Mn(II)Mn(III) states of dimanganese catalase and related model systems.

    Science.gov (United States)

    Teutloff, Christian; Schäfer, Kai-Oliver; Sinnecker, Sebastian; Barynin, Vladimir; Bittl, Robert; Wieghardt, Karl; Lendzian, Friedhelm; Lubitz, Wolfgang

    2005-11-01

    Multi-frequency EPR experiments at 9, 34 and 94 GHz are reported on the antiferromagnetically coupled mixed valence Mn(II)Mn(III) complex of manganese catalase and on several dinuclear manganese model systems. They are compared with similar experiments obtained earlier for the Mn(III)Mn(IV) states. It is demonstrated how accurate information on the G- and 55Mn hyperfine tensors can be derived from this approach. Furthermore, the effect of oxidation state, planarity of the manganese-oxygen core and the type of ligands bridging the manganese ions on the magnetic resonance parameters and the related electronic structure is investigated. 'Broken-symmetry' density functional calculations on two Mn(III)Mn(IV) complexes, including the superoxidized state of the catalase, are presented. The agreement between calculated and experimental EPR parameters and complex geometries is remarkably good. Implications of these results for the structure and function of the dimanganese catalase are discussed. Copyright 2005 John Wiley & Sons, Ltd

  13. Electric field measurements in high pressure discharges

    International Nuclear Information System (INIS)

    Mitko, S.V.; Ochkin, V.N.; Serdyuchenko, A.Yu.; Tskhai, S.N.

    2001-01-01

    Electric fields define a wide range of interactions and phenomena at different phases of matter both on micro- and macro-level. Investigation of electric fields behavior provides a key for understanding of these phenomena and their application

  14. Stream temperature investigations: field and analytic methods

    Science.gov (United States)

    Bartholow, J.M.

    1989-01-01

    This document provides guidance to the user of the U.S. Fish and Wildlife Service’s Stream Network Temperature Model (SNTEMP). Planning a temperature study is discussed in terms of understanding the management objectives and ensuring that the questions will be accurately answered with the modeling approach being used. A sensitivity analysis of SNTEMP is presented to illustrate which input variables are most important in predicting stream temperatures. This information helps prioritize data collection activities, highlights the need for quality control, focuses on which parameters can be estimated rather than measured, and offers a broader perspective on management options in terms of knowing where the biggest temperature response will be felt. All of the major input variables for stream geometry, meteorology, and hydrology are discussed in detail. Each variable is defined, with guidance given on how to measure it, what kind of equipment to use, where to obtain it from another agency, and how to calculate it if the data are in a form other than that required by SNTEMP. Examples are presented for the various forms in which water temperature, discharge, and meteorological data are commonly found. Ranges of values for certain input variables that are difficult to measure of estimate are given. Particular attention is given to those variables not commonly understood by field biologists likely to be involved in a stream temperature study. Pertinent literature is cited for each variable, with emphasis on how other people have treated particular problems and on results they have found.

  15. Idea Generation in Highly Institutionalized Fields

    DEFF Research Database (Denmark)

    Agoguè, Marine; Boxenbaum, Eva

    The early phase of innovation processes in highly institutionalized fields relies on the capabilities of actors to generate new ideas that break with the field frame. Informed by a dominant logic, a field frame shapes collective cognition and can thus prevent the generation of new ideas and block...

  16. High field electrical behaviour in lithium–phospho–vanadate glass ...

    Indian Academy of Sciences (India)

    Keywords. High field electrical behaviour; lithium–phospho–vanadate glass system. 1. Introduction. High field electrical switching behaviour is one of the fascinating properties in oxide glasses, since it exhibits reversible threshold and irreversible memory states. Several investigations have been initiated to study switching ...

  17. High School Students' Representations and Understandings of Electric Fields

    Science.gov (United States)

    Cao, Ying; Brizuela, Bárbara M.

    2016-01-01

    This study investigates the representations and understandings of electric fields expressed by Chinese high school students 15 to 16 years old who have not received high school level physics instruction. The physics education research literature has reported students' conceptions of electric fields post-instruction as indicated by students'…

  18. High field electrical behaviour in lithium–phospho–vanadate glass ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 1. High field ... The high field electrical switching behaviour of lithium–phospho–vanadate glasses has been studied by determining the current–voltage characteristics. The investigated glasses exhibit temperature, thickness and composition dependent trends.

  19. Estimation of underwater acoustic fields at high frequencies

    OpenAIRE

    Temsamani, A.B.; Vandenplas, S.; Van Biesen, L.

    2001-01-01

    In this work a parametric modeling of the underwater acoustic field is investigated in a laboratory scale at high frequencies (150-850 kHz). The aim is to develop experimentally verifiable theoretical models to investigate the acoustic field propagation in elastic and viscoelastic or porous media. To achieve this goal, the efforts have been directed to three integral parts pertaining to the development of the methods. The first part deals with the modeling of the underwater acoustic field fol...

  20. High field MRI in the diagnosis of multiple sclerosis: high field-high yield?

    Energy Technology Data Exchange (ETDEWEB)

    Wattjes, Mike P.; Barkhof, Frederik [VU University Medical Center, MS Center Amsterdam, Department of Radiology, Amsterdam (Netherlands)

    2009-05-15

    Following the approval of the U.S. Food and Drug Administration (FDA), high field magnetic resonance imaging (MRI) has been increasingly incorporated into the clinical setting. Especially in the field of neuroimaging, the number of high field MRI applications has been increased dramatically. Taking advantage on increased signal-to-noise ratio (SNR) and chemical shift, higher magnetic field strengths offer new perspectives particularly in brain imaging and also challenges in terms of several technical and physical consequences. Over the past few years, many applications of high field MRI in patients with suspected and definite multiple sclerosis (MS) have been reported including conventional and quantitative MRI methods. Conventional pulse sequences at 3 T offers higher lesion detection rates when compared to 1.5 T, particularly in anatomic regions which are important for the diagnosis of patients with MS. MR spectroscopy at 3 T is characterized by an improved spectral resolution due to increased chemical shift allowing a better quantification of metabolites. It detects significant axonal damage already in patients presenting with clinically isolated syndromes and can quantify metabolites of special interest such as glutamate which is technically difficult to quantify at lower field strengths. Furthermore, the higher susceptibility and SNR offer advantages in the field of functional MRI and diffusion tensor imaging. The recently introduced new generation of ultra-high field systems beyond 3 T allows scanning in submillimeter resolution and gives new insights into in vivo MS pathology on MRI. The objectives of this article are to review the current knowledge and level of evidence concerning the application of high field MRI in MS and to give some ideas of research perspectives in the future. (orig.)

  1. Experimental Investigation of Integrated Optical Intensive Impulse Electric Field Sensors

    International Nuclear Information System (INIS)

    Bao, Sun; Fu-Shen, Chen

    2009-01-01

    We design and fabricate an integrated optical electric field sensor with segmented electrode for intensive impulse electric field measurement. The integrated optical sensor is based on a Mach–Zehnder interferometer with segmented electrodes. The output/input character of the sensing system is analysed and measured. The maximal detectable electric field range (−75 kV/m to 245 kV/m) is obtained by analysing the results. As a result, the integrated optics electric field sensing system is suitable for transient intensive electric field measurement investigation

  2. Neutron Scattering and High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Winn, Barry L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stone, Matthew B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-11-01

    The workshop “Neutron Scattering and High Magnetic Fields” was held September 4-5, 2014 at the Oak Ridge National Laboratory (ORNL). The workshop was held in response to a recent report by the National Research Council of the National Academy of Sciences entitled “High Magnetic Field Science and Its Application in the United States: Current Status and Future Directions.”1 This report highlights the fact that neutron scattering measurements carried out in high magnetic fields provide important opportunities for new science. The workshop explored the range of the scientific discoveries that could be enabled with neutron scattering measurements at high fields (25 Tesla or larger), the various technologies that might be utilized to build specialized instruments and sample environment equipment to enable this research at ORNL, and possible routes to funding and constructing these facilities and portable high field sample environments.

  3. Liquid Droplet Dynamics in Gravity Compensating High Magnetic Field

    Science.gov (United States)

    Bojarevics, V.; Easter, S.; Pericleous, K.

    2012-01-01

    Numerical models are used to investigate behavior of liquid droplets suspended in high DC magnetic fields of various configurations providing microgravity-like conditions. Using a DC field it is possible to create conditions with laminar viscosity and heat transfer to measure viscosity, surface tension, electrical and thermal conductivities, and heat capacity of a liquid sample. The oscillations in a high DC magnetic field are quite different for an electrically conducting droplet, like liquid silicon or metal. The droplet behavior in a high magnetic field is the subject of investigation in this paper. At the high values of magnetic field some oscillation modes are damped quickly, while others are modified with a considerable shift of the oscillating droplet frequencies and the damping constants from the non-magnetic case.

  4. High field dielectric properties of piezoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, M.; Cain, M

    1999-05-01

    These guidelines are intended to enable a user to perform high field dielectric measurements on piezoelectric ceramic materials such as PZT (lead zirconium titanate). Many of the properties of piezoelectric ceramics such as PZT are highly dependant on the applied field, and therefore to make intelligent design choices, the dielectric properties are required at these field levels. These guidelines cover measurements at a fixed frequency of 1 kHz, to enable comparison with measurements made at low field. The measurement methods could all safely be extended from line frequency up to several tens of kHz, to cover a broad range of applications. However, for frequencies in the MHz range and above different factors need to be considered which are not covered in this guide. The guidelines give some general advice on high field dielectric measurements followed by a detailed description of three different measurement methods:Schering bridge; impedance analysis; and PE hysteresis loop methods. (author)

  5. Nonlinear relaxation field in charged systems under high electric fields

    International Nuclear Information System (INIS)

    Morawetz, K.

    2000-01-01

    The influence of an external electric field on the current in charged systems is investigated. The results from the classical hierarchy of density matrices are compared with the results from the quantum kinetic theory. The kinetic theory yields a systematic treatment of the nonlinear current beyond linear response. To this end the dynamically screened and field-dependent Lenard-Balescu equation is integrated analytically and the nonlinear relaxation field is calculated. The classical linear response result known as Debye - On-Sager relaxation effect is only obtained if asymmetric screening is assumed. Considering the kinetic equation of one specie the other species have to be screened dynamically while the screening with the same specie itself has to be performed statically. Different other approximations are discussed and compared. (author)

  6. Idea Generation in Highly Institutionalized Fields

    DEFF Research Database (Denmark)

    Agoguè, Marine; Boxenbaum, Eva

    The early phase of innovation processes in highly institutionalized fields relies on the capabilities of actors to generate new ideas that break with the field frame. Informed by a dominant logic, a field frame shapes collective cognition and can thus prevent the generation of new ideas and block...... innovation. An important question facing innovation research is thus how actors can generate ideas that break with the field frame in highly institutionalized fields? To answer this question, we draw on insights into dual process modeling from cognitive sciences. Dual process modeling emphasizes...... the different nature of the conscious (deliberate) and subconscious (implicit) systems involved in ideation. We further elaborate on how these two systems relate to four streams of research that management scholars evoke to model microprocesses of generating new ideas, namely metaphors, conceptual blending...

  7. High-magnetic field atomic physics

    International Nuclear Information System (INIS)

    Gay, J.C.

    1984-01-01

    This chapter discusses both the traditional developments of Zeeman techniques at strong fields and the fundamental concepts of diamagnetism. Topics considered include historical aspects, the production of high fields, the atom in a magnetic field (Hamiltonian and symmetries, the various magnetic regimes in atomic spectra), applications of the Zeeman effect at strong B fields, the Landau regime for loosely bound particles, theoretical concepts of atomic diamagnetism, and the ultra-high-field regime and quantum electrodynamics. It is concluded that the wide implications of the problem of the strongly magnetized hydrogen atom in various domains of physics and its conceptual importance concerning theoretical methods of classical and quantum mechanics justify the experimental and theoretical efforts in atomic physics

  8. KEK effort for high field magnets

    CERN Document Server

    Nakamoto, T

    2011-01-01

    KEK has emphasized efforts to develop the RHQNb3Al superconductor and a sub-scale magnet reaching 13 T towards the HL-LHC upgrade in last years. In addition, relevant R&D regarding radiation resistance has been carried out. For higher field magnets beyond 15 T, HTS in combination with A15 superconductors should be one of baseline materials. However, all these superconductors are very sensitive to stress and strain and thorough understanding of behaviour is truly desired for realization of high field magnets. KEK has launched a new research subject on stress/strain sensitivity of HTS and A15 superconductors in collaboration with the neutron diffraction facility at J-PARC and High Field Laboratory in Tohoku University. Present activity for high field magnets at KEK is reported.

  9. High magnetic fields science and technology

    CERN Document Server

    Miura, Noboru

    2003-01-01

    This three-volume book provides a comprehensive review of experiments in very strong magnetic fields that can only be generated with very special magnets. The first volume is entirely devoted to the technology of laboratory magnets: permanent, superconducting, high-power water-cooled and hybrid; pulsed magnets, both nondestructive and destructive (megagauss fields). Volumes 2 and 3 contain reviews of the different areas of research where strong magnetic fields are an essential research tool. These volumes deal primarily with solid-state physics; other research areas covered are biological syst

  10. Highly educated but in the wrong field?

    DEFF Research Database (Denmark)

    Reimer, David; Steinmetz, Stephanie

    2009-01-01

      This paper investigates the impact of gender differences in tertiary education, i.e., field of study and level of tertiary degree, on two selected labour market risks: unemployment and low-status jobs. Using Labour Force Survey data from the year 2000, results of the logistic regression models...... in tertiary education leads to similar outcomes in two very different institutional contexts....

  11. High-field dipoles for future accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Wipf, S.L.

    1984-09-01

    This report presents the concept for building superconducting accelerator dipoles with record high fields. Economic considerations favor the highest possible current density in the windings. Further discussion indicates that there is an optimal range of pinning strength for a superconducting material and that it is not likely for multifilamentary conductors to ever equal the potential performance of tape conductors. A dipole design with a tape-wound, inner high-field winding is suggested. Methods are detailed to avoid degradation caused by flux jumps and to overcome problems with the dipole ends. Concerns for force support structure and field precision are also addressed. An R and D program leading to a prototype 11-T dipole is outlined. Past and future importance of superconductivity to high-energy physics is evident from a short historical survey. Successful dipoles in the 10- to 20-T range will allow interesting options for upgrading present largest accelerators.

  12. Molecular dynamics in high electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Apostol, M., E-mail: apoma@theory.nipne.ro; Cune, L.C.

    2016-06-15

    Highlights: • New method for rotation molecular spectra in high electric fields. • Parametric resonances – new features in spectra. • New elementary excitations in polar solids from dipolar interaction (“dipolons”). • Discussion about a possible origin of the ferroelectricity from dipolar interactions. - Abstract: Molecular rotation spectra, generated by the coupling of the molecular electric-dipole moments to an external time-dependent electric field, are discussed in a few particular conditions which can be of some experimental interest. First, the spherical-pendulum molecular model is reviewed, with the aim of introducing an approximate method which consists in the separation of the azimuthal and zenithal motions. Second, rotation spectra are considered in the presence of a static electric field. Two particular cases are analyzed, corresponding to strong and weak fields. In both cases the classical motion of the dipoles consists of rotations and vibrations about equilibrium positions; this motion may exhibit parametric resonances. For strong fields a large macroscopic electric polarization may appear. This situation may be relevant for polar matter (like pyroelectrics, ferroelectrics), or for heavy impurities embedded in a polar solid. The dipolar interaction is analyzed in polar condensed matter, where it is shown that new polarization modes appear for a spontaneous macroscopic electric polarization (these modes are tentatively called “dipolons”); one of the polarization modes is related to parametric resonances. The extension of these considerations to magnetic dipoles is briefly discussed. The treatment is extended to strong electric fields which oscillate with a high frequency, as those provided by high-power lasers. It is shown that the effect of such fields on molecular dynamics is governed by a much weaker, effective, renormalized, static electric field.

  13. Molecular dynamics in high electric fields

    International Nuclear Information System (INIS)

    Apostol, M.; Cune, L.C.

    2016-01-01

    Highlights: • New method for rotation molecular spectra in high electric fields. • Parametric resonances – new features in spectra. • New elementary excitations in polar solids from dipolar interaction (“dipolons”). • Discussion about a possible origin of the ferroelectricity from dipolar interactions. - Abstract: Molecular rotation spectra, generated by the coupling of the molecular electric-dipole moments to an external time-dependent electric field, are discussed in a few particular conditions which can be of some experimental interest. First, the spherical-pendulum molecular model is reviewed, with the aim of introducing an approximate method which consists in the separation of the azimuthal and zenithal motions. Second, rotation spectra are considered in the presence of a static electric field. Two particular cases are analyzed, corresponding to strong and weak fields. In both cases the classical motion of the dipoles consists of rotations and vibrations about equilibrium positions; this motion may exhibit parametric resonances. For strong fields a large macroscopic electric polarization may appear. This situation may be relevant for polar matter (like pyroelectrics, ferroelectrics), or for heavy impurities embedded in a polar solid. The dipolar interaction is analyzed in polar condensed matter, where it is shown that new polarization modes appear for a spontaneous macroscopic electric polarization (these modes are tentatively called “dipolons”); one of the polarization modes is related to parametric resonances. The extension of these considerations to magnetic dipoles is briefly discussed. The treatment is extended to strong electric fields which oscillate with a high frequency, as those provided by high-power lasers. It is shown that the effect of such fields on molecular dynamics is governed by a much weaker, effective, renormalized, static electric field.

  14. Numerical investigation of space charge electric field for a sheet ...

    Indian Academy of Sciences (India)

    Numerical investigation of space charge electric field for a sheet electron beam between two conducting planes. ARTI GOKHALE, PREETI VYAS, J PANIKAR, Y CHOYAL and K P MAHESHWARI. School of Physics, Devi Ahilya University, Khandwa Road, Indore 452 017, India. MS received 26 June 2000; revised 12 April ...

  15. High electric field conduction in low-alkali boroaluminosilicate glass

    Science.gov (United States)

    Dash, Priyanka; Yuan, Mengxue; Gao, Jun; Furman, Eugene; Lanagan, Michael T.

    2018-02-01

    Electrical conduction in silica-based glasses under a low electric field is dominated by high mobility ions such as sodium, and there is a transition from ionic transport to electronic transport as the electric field exceeds 108 V/m at low temperatures. Electrical conduction under a high electric field was investigated in thin low-alkali boroaluminosilicate glass samples, showing nonlinear conduction with the current density scaling approximately with E1/2, where E is the electric field. In addition, thermally stimulated depolarization current (TSDC) characterization was carried out on room-temperature electrically poled glass samples, and an anomalous discharging current flowing in the same direction as the charging current was observed. High electric field conduction and TSDC results led to the conclusion that Poole-Frenkel based electronic transport occurs in the mobile-cation-depleted region adjacent to the anode, and accounts for the observed anomalous current.

  16. Atomic emission spectroscopy in high electric fields

    International Nuclear Information System (INIS)

    Bailey, J.E.; Filuk, A.B.; Carlson, A.L.

    1995-01-01

    Pulsed-power driven ion diodes generating quasi-static, ∼10 MV/cm, 1-cm scale-length electric fields are used to accelerate lithium ion beams for inertial confinement fusion applications. Atomic emission spectroscopy measurements contribute to understanding the acceleration gap physics, in particular by combining time- and space-resolved measurements of the electric field with the Poisson equation to determine the charged particle distributions. This unique high-field configuration also offers the possibility to advance basic atomic physics, for example by testing calculations of the Stark-shifted emission pattern, by measuring field ionization rates for tightly-bound low-principal-quantum-number levels, and by measuring transition-probability quenching

  17. High magnetic fields in the USA

    Science.gov (United States)

    Campbell, Laurence J.; Parkin, Don E.; Crow, Jack E.; Schneider-Muntau, Hans J.; Sullivan, Neil S.

    During the past thirty years research using high magnetic fields has technically evolved in the manner, but not the magnitude, of the so-called big science areas of particle physics, plasma physics, neutron scattering, synchrotron light scattering, and astronomy. Starting from the laboratories of individual researchers it moved to a few larger universities, then to centralized national facilities with research and maintenance staffs, and, finally, to joint international ventures to build unique facilities, as illustrated by the subject of this conference. To better understand the nature of this type of research and its societal justification it is helpful to compare it, in general terms, with the aforementioned big-science fields. High magnetic field research differs from particle physics, plasma physics, and astronomy in three respects: (1) it is generic research that cuts across a wide range of scientific disciplines in physics, chemistry, biology, medicine, and engineering; (2) it studies materials and processes that are relevant for a variety of technological applications and it gives insight into biological processes; (3) it has produced, at least, comparably significant results with incomparably smaller resources. Unlike neutron and synchrotron light scattering, which probe matter, high magnetic fields change the thermodynamic state of matter. This change of state is fundamental and independent of other state variables, such as pressure and temperature. After the magnetic field is applied, various techniques are then used to study the new state.

  18. Results of investigations at the Ahuachapan geothermal field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, B.; Goff, F.; Van Eeckhout, E.; Hanold, B. (comps.)

    1990-04-01

    Well logging operations were performed in eight of the geothermal wells at Ahuachapan. High-temperature downhole instruments, including a temperature/rabbit, caliper, fluid velocity spinner/temperature/pressure (STP), and fluid sampler, were deployed in each well. The caliper tool was used primarily to determine if chemical deposits were present in well casings or liners and to investigate a suspected break in the casing in one well. STP logs were obtained from six of the eight wells at various flow rates ranging from 30 to 80 kg/s. A static STP log was also run with the wells shut-in to provide data to be used in the thermodynamic analysis of several production wells. The geochemical data obtained show a system configuration like that proposed by C. Laky and associates in 1989. Our data indicate recharge to the system from the volcanic highlands south of the field. Additionally, our data indicate encroachment of dilute fluids into deeper production zones because of overproduction. 17 refs., 50 figs., 10 tabs.

  19. Marine ARM GPCI Investigation of Clouds (MAGIC) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Ernie R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-01

    The Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign, which deployed the second ARM Mobile Facility (AMF2) aboard the Horizon Lines cargo container ship Spirit as it ran its regular route between Los Angeles, California and Honolulu, Hawaii, measured properties of clouds and precipitation, aerosols, radiation, and atmospheric, meteorological, and oceanic conditions with the goal of obtaining statistics of these properties to achieve better understanding of the transition between stratocumulus and cumulus cloud regimes that occur in that region. This Sc-Cu transition is poorly represented in models, and a major reason for this is the lack of high-quality and comprehensive data that can be used to constrain, validate, and improve model representation of the transition. MAGIC consisted of 20 round trips between Los Angeles and Honolulu, and thus over three dozen transects through the transition, totaling nearly 200 days at sea between September, 2012 and October, 2013. During this time MAGIC collected a unique and unprecedented data set, including more than 550 successful radiosonde launches. An Intensive Observational Period (IOP) occurred in July, 2013 during which more detailed measurements of the atmospheric structure were made. MAGIC was very successful in its operations and overcame numerous logistical and technological challenges, clearly demonstrating the feasibility of a marine AMF2 deployment and the ability to make accurate measurements of clouds and precipitation, aerosols, and radiation while at sea.

  20. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  1. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  2. Physics of semiconductors in high magnetic fields

    CERN Document Server

    Miura, Noboru

    2008-01-01

    This book summarizes most of the fundamental physical phenomena which semiconductors and their modulated structures exhibit in high magnetic fields. Readers can learn not only the basic theoretical background but also the present state of the art from the most advanced data in this rapidly growing research area.

  3. High-performance phase-field modeling

    KAUST Repository

    Vignal, Philippe

    2015-04-27

    Many processes in engineering and sciences involve the evolution of interfaces. Among the mathematical frameworks developed to model these types of problems, the phase-field method has emerged as a possible solution. Phase-fields nonetheless lead to complex nonlinear, high-order partial differential equations, whose solution poses mathematical and computational challenges. Guaranteeing some of the physical properties of the equations has lead to the development of efficient algorithms and discretizations capable of recovering said properties by construction [2, 5]. This work builds-up on these ideas, and proposes novel discretization strategies that guarantee numerical energy dissipation for both conserved and non-conserved phase-field models. The temporal discretization is based on a novel method which relies on Taylor series and ensures strong energy stability. It is second-order accurate, and can also be rendered linear to speed-up the solution process [4]. The spatial discretization relies on Isogeometric Analysis, a finite element method that possesses the k-refinement technology and enables the generation of high-order, high-continuity basis functions. These basis functions are well suited to handle the high-order operators present in phase-field models. Two-dimensional and three dimensional results of the Allen-Cahn, Cahn-Hilliard, Swift-Hohenberg and phase-field crystal equation will be presented, which corroborate the theoretical findings, and illustrate the robustness of the method. Results related to more challenging examples, namely the Navier-Stokes Cahn-Hilliard and a diusion-reaction Cahn-Hilliard system, will also be presented. The implementation was done in PetIGA and PetIGA-MF, high-performance Isogeometric Analysis frameworks [1, 3], designed to handle non-linear, time-dependent problems.

  4. Investigations of field instability of ferrofluid in hypergravity and microgravity

    Directory of Open Access Journals (Sweden)

    Theng Yee Chong

    2012-03-01

    Full Text Available The field instability of the free surface of ferrofluid was investigated under microgravity and hypergravity environments conducted by parabolic flight. It is observed that the perturbation was suppressed under hypergravity, whereas at the microgravity condition, it appeared to have only slight increase in the amplitude of the perturbation peaks compared to the case of ground condition. Besides, an observation of peak-trough distance showed that not only the peak, but the trough was also very much dependent on the applied magnetic field. The difference of magnetic pole (north and south had shown to be a factor to the perturbation as well.

  5. Investigations of field instability of ferrofluid in hypergravity and microgravity

    Science.gov (United States)

    Chong, Theng Yee; Ho, Kent Loong; Ong, Boon Hoong

    2012-03-01

    The field instability of the free surface of ferrofluid was investigated under microgravity and hypergravity environments conducted by parabolic flight. It is observed that the perturbation was suppressed under hypergravity, whereas at the microgravity condition, it appeared to have only slight increase in the amplitude of the perturbation peaks compared to the case of ground condition. Besides, an observation of peak-trough distance showed that not only the peak, but the trough was also very much dependent on the applied magnetic field. The difference of magnetic pole (north and south) had shown to be a factor to the perturbation as well.

  6. Investigation of energy spectrum structure in a system atom + strong external electromagnetic field

    International Nuclear Information System (INIS)

    Volkova, E.A.; Popov, A.M.; Tikhonova, O.V.

    1996-01-01

    Method of direct numerical integration of nonstationary Schroedinger equation is used for investigation into dynamics of quantum system with short-range potential under the cooperative effect of high-frequency electromagnetic field with super atomic value of intensity and low-frequency field with low radiation intensity

  7. Silicon Photomultiplier Performance in High ELectric Field

    Science.gov (United States)

    Montoya, J.; Morad, J.

    2016-12-01

    Roughly 27% of the universe is thought to be composed of dark matter. The Large Underground Xenon (LUX) relies on the emission of light from xenon atoms after a collision with a dark matter particle. After a particle interaction in the detector, two things can happen: the xenon will emit light and charge. The charge (electrons), in the liquid xenon needs to be pulled into the gas section so that it can interact with gas and emit light. This allows LUX to convert a single electron into many photons. This is done by applying a high voltage across the liquid and gas regions, effectively ripping electrons out of the liquid xenon and into the gas. The current device used to detect photons is the photomultiplier tube (PMT). These devices are large and costly. In recent years, a new technology that is capable of detecting single photons has emerged, the silicon photomultiplier (SiPM). These devices are cheaper and smaller than PMTs. Their performance in a high electric fields, such as those found in LUX, are unknown. It is possible that a large electric field could introduce noise on the SiPM signal, drowning the single photon detection capability. My hypothesis is that SiPMs will not observe a significant increase is noise at an electric field of roughly 10kV/cm (an electric field within the range used in detectors like LUX). I plan to test this hypothesis by first rotating the SiPMs with no applied electric field between two metal plates roughly 2 cm apart, providing a control data set. Then using the same angles test the dark counts with the constant electric field applied. Possibly the most important aspect of LUX, is the photon detector because it's what detects the signals. Dark matter is detected in the experiment by looking at the ratio of photons to electrons emitted for a given interaction in the detector. Interactions with a low electron to photon ratio are more like to be dark matter events than those with a high electron to photon ratio. The ability to

  8. Investigations of field instability of ferrofluid in hypergravity and microgravity

    OpenAIRE

    Theng Yee Chong; Kent Loong Ho; Boon Hoong Ong

    2012-01-01

    The field instability of the free surface of ferrofluid was investigated under microgravity and hypergravity environments conducted by parabolic flight. It is observed that the perturbation was suppressed under hypergravity, whereas at the microgravity condition, it appeared to have only slight increase in the amplitude of the perturbation peaks compared to the case of ground condition. Besides, an observation of peak-trough distance showed that not only the peak, but the trough was also very...

  9. Investigating Call Drops with Field Measurements on Commercial Mobile Phones

    DEFF Research Database (Denmark)

    Messina, Alessandro; Caragea, Gabriel; Compta, Pol Torres

    2013-01-01

    can be done per day. In this paper we present a new methodology to investigate call drops by using mobile phones to do the measurements following the concept of citizen sensing. Therefore, a mobile application for Android is made that collects all necessary data and dumps the measurement results...... mobile phone and network. This low cost variant of field testing is developed for call drops but could be used for any other parameter of interest....

  10. Shemya AFB, Alaska 1992 IRP field investigation report

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). As a part of the IRP program, field investigations were performed in 1992 to obtain the information needed to assess what future actions willneed to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites during the 1992 field investigation included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities.

  11. High field superconductor development and understanding

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David C. [Florida State Univ., Tallahassee, FL (United States); Lee, Peter J. [Florida State Univ., Tallahassee, FL (United States); Tarantini, Chiara [Florida State Univ., Tallahassee, FL (United States)

    2014-09-28

    All present circular accelerators use superconducting magnets to bend and to focus the particle beams. The most powerful of these machines is the large hadron collider (LHC) at CERN. The main ring dipole magnets of the LHC are made from Nb-Ti but, as the machine is upgraded to higher luminosity, more powerful magnets made of Nb3Sn will be required. Our work addresses how to make the Nb3Sn conductors more effective and more suitable for use in the LHC. The most important property of the superconducting conductor used for an accelerator magnet is that it must have very high critical current density, the property that allows the generation of high magnetic fields in small spaces. Nb3Sn is the original high field superconductor, the material which was discovered in 1960 to allow a high current density in the field of about 9 T. For the high luminosity upgrade of the LHC, much higher current densities in fields of about 12 Tesla will be required. The critical value of the current density is of order 2600 A/mm2 in a field of 12 Tesla. But there are very important secondary factors that complicate the attainment of this critical current density. The first is that the effective filament diameter must be no larger than about 40 µm. The second factor is that 50% of the cross-section of the Nb3Sn conductor that is pure copper must be protected from any poisoning by any Sn leakage through the diffusion barrier that protects the package of niobium and tin from which the Nb3Sn is formed by a high temperature reaction. These three, somewhat conflicting requirements, mean that optimization of the conductor is complex. The work described in this contract report addresses these conflicting requirements. They show that very sophisticated characterizations can uncover the way to satisfy all 3 requirements and they also suggest that the ultimate optimization of Nb3Sn is still not yet in sight

  12. High field conditioning of cryogenic RF cavities

    International Nuclear Information System (INIS)

    Cole, M.; Debiak, T.; Lom, C.; Shephard, W.; Sredniawski, J.

    1993-01-01

    Space-based and other related accelerators have conditioning and operation requirements that are not found in most machines. The use of cryogenic copper, relatively poor vacuum, and limited power storage and operating time put unusual demands on the high-field conditioning process and present some concerns. Two CW cryogenic engineering model open-quotes sparkerclose quotes cavities have been fabricated and tested to fairly high field levels. Tests included initial and repeated conditioning as well as sustained RF operations. The two cavities were an engineering model TDL and an engineering model RFQ. Both cavities operated at 425 MHz. The DTL was conditioned to 46 MV/m at 100% duty factor (CW) at cryogenic temperature. This corresponds to a gap voltage of 433 kV and a real estate accelerating gradient (energy gain/total cavity length) of 6.97 MV/m. The authors believe this to be record performance for cryo CW operation. During cryo pulsed operation, the same cavity reached 48 MV/m with 200 μsec pulses at 0.5% DF. The RFQ was conditioned to 30 MV/m CW at cryo, 85 kV gap voltage. During a brief period of cryo pulsed operation, the RFQ operated at 46 MV/m, or 125 kV gap voltage. Reconditioning experiments were performed on both cavities and no problems were encountered. It should be noted that the vacuum levels were not very stringent during these tests and no special cleanliness or handling procedures were followed. The results of these tests indicate that cavities can run CW without difficulty at cryogenic temperatures at normal conservative field levels. Higher field operation may well be possible, and if better vacuums are used and more attention is paid to cleanliness, much higher fields may be attainable

  13. Investigation of thin manganite films at strong pulsed electric and magnetic fields

    OpenAIRE

    Cimmperman, Piotras

    2006-01-01

    The main aim of this work was to investigate electrical conductivity of La-Ca(Sr)-MnO thin films at high pulsed electric and magnetic fields and to clear up the possibilities to use these materials for high pulsed magnetic field sensor and fault current limiter applications. The dissertation consists of the preface, six chapters, summary and main conclusions, references, list of publications and abstract (in Lithuanian). The main objectives of the work, scientific novelty, goals, valida...

  14. Structural investigations of Great Basin geothermal fields: Applications and implications

    Energy Technology Data Exchange (ETDEWEB)

    Faulds, James E [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Hinz, Nicholas H. [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Coolbaugh, Mark F [Great Basin Center for Geothermal Energy, Univ. of Nevada, Reno, NV (United States)

    2010-11-01

    Because fractures and faults are commonly the primary pathway for deeply circulating hydrothermal fluids, structural studies are critical to assessing geothermal systems and selecting drilling targets for geothermal wells. Important tools for structural analysis include detailed geologic mapping, kinematic analysis of faults, and estimations of stress orientations. Structural assessments are especially useful for evaluating geothermal fields in the Great Basin of the western USA, where regional extension and transtension combine with high heat flow to generate abundant geothermal activity in regions having little recent volcanic activity. The northwestern Great Basin is one of the most geothermally active areas in the USA. The prolific geothermal activity is probably due to enhanced dilation on N- to NNE-striking normal faults induced by a transfer of NW-directed dextral shear from the Walker Lane to NW-directed extension. Analysis of several geothermal fields suggests that most systems occupy discrete steps in normal fault zones or lie in belts of intersecting, overlapping, and/or terminating faults. Most fields are associated with steeply dipping faults and, in many cases, with Quaternary faults. The structural settings favoring geothermal activity are characterized by subvertical conduits of highly fractured rock along fault zones oriented approximately perpendicular to the WNW-trending least principal stress. Features indicative of these settings that may be helpful in guiding exploration for geothermal resources include major steps in normal faults, interbasinal highs, groups of relatively low discontinuous ridges, and lateral jogs or terminations of mountain ranges.

  15. High-magnetic-field research collaborations

    International Nuclear Information System (INIS)

    Goettee, J.

    1998-01-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to develop collaborations with the academic community to exploit scientific research potential of the pulsed magnetic fields that might be possible with electrically pulsed devices, as well as magneto-cumulative generators. The author started with a campaign of experiments using high-explosive-driven flux compression generators. The campaign's objective was to explore completely novel ideas in condensed-matter physics and chemistry. The initiative was very successful in pulling together top researchers from around the world

  16. High-intensity, focused ultrasonic fields

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1988-01-01

    machines marketed by companies in Germany and France, in particular. Two main types of ESWL systems are prevailing, the spark gap-based and the piezoelectric disk-based systems. This paper is introduced by a brief reconsideration of the features of pressure waves in water produced by an electrical...... distribution, etc. involving nonlinearity, diffraction, and absorption in the high-intensity focused ultrasonic fields produced by an ellipsoid as well as a spherical cap focusing geometry. Data from the development of an ESWL of the piezoelectric disk type are reported including demands to transducers...

  17. Investigation of Radiation Fields at Aircraft Altitudes (invited paper)

    International Nuclear Information System (INIS)

    O'Sullivan, D.; Bartlett, D.; Grillmaier, R.; Heinrich, W.; Lindborg, L.; Schraube, H.; Silari, M.; Tommasino, L.; Zhou, D.

    2000-01-01

    Cosmic rays are believed to originate from several possible sources and recent research suggests that the bulk originate from the gas and dust of the interstellar medium and are accelerated by strong shock waves driven by supernova explosions. Cosmic ray particles are made up of γ98.5% hydrogen and helium and only 1.5% have charges greater than 2. Their average energy is about 1 GeV/nucleon and they lose energy through ionisation interactions and nuclear interactions with atoms of air as they penetrate deeply into the Earth's atmosphere. A very complicated radiation field develops as particles are generated by successive interaction of primary and secondary nuclei and a cascade of hadrons is produced in the atmosphere. The intensity of particles reaches a maximum at about 20 km above sea level (γ60 g.cm -2 ). The relative abundances of different particles change with depth within the atmosphere and mainly muons which are the decay products of charged mesons, reach sea level because of their weak interaction. The radiation field produced and consequently its effect on aircrew and frequent travellers is a matter of some concern. This paper outlines the results of investigations carried out to determine the characteristics of this radiation field and assess its impact on aircrew. (author)

  18. FINESSE: Field Investigations to Enable Solar System Science and Exploration

    Science.gov (United States)

    Heldmann, Jennifer; Lim, Darlene; Colaprete, Anthony

    2015-01-01

    The FINESSE (Field Investigations to Enable Solar System Science and Exploration) team is focused on a science and exploration field-based research program aimed at generating strategic knowledge in preparation for the human and robotic exploration of the Moon, near-Earth asteroids (NEAs) and Phobos and Deimos. We follow the philosophy that "science enables exploration and exploration enables science." 1) FINESSE Science: Understand the effects of volcanism and impacts as dominant planetary processes on the Moon, NEAs, and Phobos & Deimos. 2) FINESSE Exploration: Understand which exploration concepts of operations (ConOps) and capabilities enable and enhance scientific return. To accomplish these objectives, we are conducting an integrated research program focused on scientifically-driven field exploration at Craters of the Moon National Monument and Preserve in Idaho and at the West Clearwater Lake Impact Structure in northern Canada. Field deployments aimed at reconnaissance geology and data acquisition were conducted in 2014 at Craters of the Moon National Monument and Preserve. Targets for data acquisition included selected sites at Kings Bowl eruptive fissure, lava field and blowout crater, Inferno Chasm vent and outflow channel, North Crater lava flow and Highway lava flow. Field investigation included (1) differential GPS (dGPS) measurements of lava flows, channels (and ejecta block at Kings Bowl); (2) LiDAR imaging of lava flow margins, surfaces and other selected features; (3) digital photographic documentation; (4) sampling for geochemical and petrographic analysis; (5) UAV aerial imagery of Kings Bowl and Inferno Chasm features; and (6) geologic assessment of targets and potential new targets. Over the course of the 5-week field FINESSE campaign to the West Clearwater Impact Structure (WCIS) in 2014, the team focused on several WCIS research topics, including impactites, central uplift formation, the impact-generated hydrothermal system, multichronometer

  19. Shemya AFB, Alaska 1992 IRP field investigation report

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). Field investigations were performed in 1992 to obtain the information needed to assess what future actions will need to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. Geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities. This report, appendices B, C, and D contains information on the following: geophysical contour maps and profile plots; human health risk assessment; and ecological risk assessment.

  20. Shemya AFB, Alaska 1992 IRP field investigation report

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force's Installation Restoration Program (IRP). Field investigations were performed in 1992 to obtain the information needed to assess what future actions will need to be carried out at each site. The island's drinking water supply was also investigated. Activities completed at 10 selected sites included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal, to be avoided during drilling activities. This report contains appendices E and F with information on the following: soil boring logs, and data validation of samples analyzed.

  1. Investigation of the electric field in irradiated diamond sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Barvich, Tobias; Boer, Wim de; Dierlamm, Alexander; Eber, Robert; Nuernberg, Andreas; Steck, Pia [Institut fuer Experimentelle Kernphysik (IEKP), Karlsruher Institut fuer Technologie (KIT) (Germany); Dabrowski, Anne; Guthoff, Moritz [CERN (Switzerland)

    2015-07-01

    The Beam Condition Monitoring Leakage (BCML) system is a beam monitoring device in the CMS experiment at the LHC. As detectors 32 poly-crystalline CVD diamond sensors are positioned in a ring around the beam pipe at a distance of +/-1.8 m and +/-14.4 m from the interaction point. The radiation hardness of the diamond sensors in terms of measured signal during operation was significantly lower than expected based on laboratory measurements. At high particle rates, like they occur during the operation of the LHC, charge carriers can be trapped in defects created by radiation. This space charge is expected to modify the electrical field in the sensor bulk and hence to reduce the charge collection efficiency. This modified electrical field has been indirectly measured in the laboratory using the Transient Current Technique (TCT) method in irradiated single crystal CVD diamond. This rate dependent effect was simulated with the software 'SILVACO ATLAS' and the obtained electrical field was used to calculate a TCT measurement pulse. The results of the TCT measurements will be compared to the simulation.

  2. Electric and magnetic field measurements in a high voltage center.

    Science.gov (United States)

    Safigianni, Anastasia S; Spyridopoulos, Anastasios I; Kanas, Vasilis L

    2012-01-01

    This paper investigates the electric and magnetic fields inside a large high voltage center constituted both of 400/150 and 150/20 kV substation areas. Results of previous field measurements and calculations in substations, made by the authors of this paper or other researchers, are presented first. The basic data distinguishing the examined center from previously examined substations follow. The main results of the field measurements in the areas of the above-mentioned center are presented in relevant diagrams. General conclusions arising from the comparison of the measured field values with relevant reference levels in force for safe public and occupational exposure as well as with the results of previous research are finally given.

  3. Results of verification and investigation of wind velocity field forecast. Verification of wind velocity field forecast model

    International Nuclear Information System (INIS)

    Ogawa, Takeshi; Kayano, Mitsunaga; Kikuchi, Hideo; Abe, Takeo; Saga, Kyoji

    1995-01-01

    In Environmental Radioactivity Research Institute, the verification and investigation of the wind velocity field forecast model 'EXPRESS-1' have been carried out since 1991. In fiscal year 1994, as the general analysis, the validity of weather observation data, the local features of wind field, and the validity of the positions of monitoring stations were investigated. The EXPRESS which adopted 500 m mesh so far was improved to 250 m mesh, and the heightening of forecast accuracy was examined, and the comparison with another wind velocity field forecast model 'SPEEDI' was carried out. As the results, there are the places where the correlation with other points of measurement is high and low, and it was found that for the forecast of wind velocity field, by excluding the data of the points with low correlation or installing simplified observation stations to take their data in, the forecast accuracy is improved. The outline of the investigation, the general analysis of weather observation data and the improvements of wind velocity field forecast model and forecast accuracy are reported. (K.I.)

  4. High Performance Clocks and Gravity Field Determination

    Science.gov (United States)

    Müller, J.; Dirkx, D.; Kopeikin, S. M.; Lion, G.; Panet, I.; Petit, G.; Visser, P. N. A. M.

    2018-02-01

    Time measured by an ideal clock crucially depends on the gravitational potential and velocity of the clock according to general relativity. Technological advances in manufacturing high-precision atomic clocks have rapidly improved their accuracy and stability over the last decade that approached the level of 10^{-18}. This notable achievement along with the direct sensitivity of clocks to the strength of the gravitational field make them practically important for various geodetic applications that are addressed in the present paper. Based on a fully relativistic description of the background gravitational physics, we discuss the impact of those highly-precise clocks on the realization of reference frames and time scales used in geodesy. We discuss the current definitions of basic geodetic concepts and come to the conclusion that the advances in clocks and other metrological technologies will soon require the re-definition of time scales or, at least, clarification to ensure their continuity and consistent use in practice. The relative frequency shift between two clocks is directly related to the difference in the values of the gravity potential at the points of clock's localization. According to general relativity the relative accuracy of clocks in 10^{-18} is equivalent to measuring the gravitational red shift effect between two clocks with the height difference amounting to 1 cm. This makes the clocks an indispensable tool in high-precision geodesy in addition to laser ranging and space geodetic techniques. We show how clock measurements can provide geopotential numbers for the realization of gravity-field-related height systems and can resolve discrepancies in classically-determined height systems as well as between national height systems. Another application of clocks is the direct use of observed potential differences for the improved recovery of regional gravity field solutions. Finally, clock measurements for space-borne gravimetry are analyzed along with

  5. "Molecular" MR imaging at high fields.

    Science.gov (United States)

    Gore, John C; Zu, Zhongliang; Wang, Ping; Li, Hua; Xu, Junzhong; Dortch, Richard; Gochberg, Daniel F

    2017-05-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) have contributed considerably to clinical radiology, and a variety of MR techniques have been developed to evaluate pathological processes as well as normal tissue biology at the cellular and molecular level. However, in comparison to nuclear imaging, MRI has relatively poor sensitivity for detecting true molecular changes or for detecting the presence of targeted contrast agents, though these remain under active development. In recent years very high field (7T and above) MRI systems have been developed for human studies and these provide new opportunities and technical challenges for molecular imaging. We identify 5 types of intrinsic contrast mechanisms that do not require the use of exogenous agents but which can provide molecular and cellular information. We can derive information on tissue composition by (i) imaging different nuclei, especially sodium (ii) exploiting chemical shift differences as in MRS (iii) exploiting specific relaxation mechanisms (iv) exploiting tissue differences in the exchange rates of molecular species such as amides or hydroxyls and (v) differences in susceptibility. The increased signal strength at higher fields enables higher resolution images to be acquired, along with increased sensitivity to detecting subtle effects caused by molecular changes in tissues. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Investigation of lasers based on coupled waveguides by near-field scanning optical microscopy

    Science.gov (United States)

    Polubavkina, Yu S.; Gordeev, N. Yu; Payusov, A. S.; Kryzhanovskaya, N. V.; Moiseev, E. I.; Zubov, F. I.; Mintairov, S. A.; Kalyuzhnyy, N. A.; Kulagina, M. M.; Shernyakov, Yu M.; Maximov, M. V.; Zhukov, A. E.

    2017-11-01

    We have investigated near field intensity distributions of InGaAs/GaAs/AlGaAs lasers possessing broadened waveguides based on coupled large optical cavity structures (CLOC) by scanning near-field optical microscopy (SNOM). The concept allows effective suppressing of the transverse high-order mode lasing. The obtained results can be considered to be the direct proof of pure transverse single-mode emission of the CLOC lasers.

  7. The investigation of fetal doses in mantle field irradiation

    International Nuclear Information System (INIS)

    Karacam, S. C; Gueralp, O. S; Oeksuez, D. C; Koca, A.; Cepni, I.; Cepni, K.; Bese, N.

    2009-01-01

    To determine clinically the fetal dose from irradiation of Hodgkin's disease during pregnancy and to quantify the components of fetal dose using phantom measurements. The fetal dose was measured with phantom measurements using thermoluminescent dosemeters (TLDs). Phantom measurements were performed by simulating the treatment conditions on an anthropomorphic phantom. TLDs were placed on the phantom 41, 44, 46.5 and 49.5 cm from the centre of the treatment field. Two TLDs were placed on the surface of the phantom. The estimated total dose to all the TLDs ranged from 8.8 to 13.2 cGy for treatment with 60 Co and from 8.2 to 11.8 cGy for 4 MV photons. It was concluded that the doses in different sections were evaluated to investigate dose changes in different points and depths of fetal tissues in phantom. Precise planning and the use of supplemental fetal shielding may help reduce fetal exposure. (authors)

  8. Scientific investigation plan for initial engineered barrier system field tests

    International Nuclear Information System (INIS)

    Wunan Lin.

    1993-02-01

    The purpose of this Scientific Investigation Plan (SIP) is to describe tests known as Initial Engineered Barrier System Field Tests (IEBSFT) and identified by Work Breakdown Structure as WBS 1.2.2.2.4. The IEBSFT are precursors to the Engineered Barrier System Field Test (EBSFT), WBS 1.2.2.2.4, to be conducted in the Exploratory Study Facility (ESF) at Yucca Mountain. The EBSFT and IEBSFT are designed to provide information on the interaction between waste packages (simulated by heated containers) and the surrounding rock mass, its vadose water, and infiltrated water. Heater assemblies will be installed in drifts or boreholes openings and heated to measure moisture movement during heat-up and subsequent cool-down of the rock mass. In some of the tests, infiltration of water into the heated rock mass will be studied. Throughout the heating and cooling cycle, instruments installed in the rock will monitor such parameters as temperature, moisture content, concentration of some chemical species, and stress and strain. Rock permeability measurements, rock and fluid (water and gas) sampling, and fracture pattern measurements will also be made before and after the test

  9. INVESTIGATION OF POLARIZATION PHASE DIFFERENCE RELATED TO FOREST FIELDS CHARACTERIZATIONS

    Directory of Open Access Journals (Sweden)

    M. Majidi

    2013-09-01

    Full Text Available The information content of Synthetic Aperture Radar (SAR data significantly included in the radiometric polarization channels, hence polarimetric SAR data should be analyzed in relation with target structure. The importance of the phase difference between two co-polarized scattered signals due to the possible association between the biophysical parameters and the measured Polarization Phase Difference (PPD statistics of the backscattered signal recorded components has been recognized in geophysical remote sensing. This paper examines two Radarsat-2 images statistics of the phase difference to describe the feasibility of relationship with the physical properties of scattering targets and tries to understand relevance of PPD statistics with various types of forest fields. As well as variation of incidence angle due to affecting on PPD statistics is investigated. The experimental forest pieces that are used in this research are characterized white pine (Pinus strobus L., red pine (Pinus resinosa Ait., jack pine (Pinus banksiana Lamb., white spruce (Picea glauca (Moench Voss, black spruce (Picea mariana (Mill B.S.P., poplar (Populus L., red oak (Quercus rubra L. , aspen and ground vegetation. The experimental results show that despite of biophysical parameters have a wide diversity, PPD statistics are almost the same. Forest fields distributions as distributed targets have close to zero means regardless of the incidence angle. Also, The PPD distribution are function of both target and sensor parameters, but for more appropriate examination related to PPD statistics the observations should made in the leaf-off season or in bands with lower frequencies.

  10. Tritium system for compact high field devices

    International Nuclear Information System (INIS)

    Roccella, M.; Bonizzoni, G.; Chiesa, P.; Ghezzi, F.; Nassi, M.; Pavesi, U.; Amedeo, P.; Boschetti, G.; Giffanti, F.; Moriggio, A.

    1988-01-01

    Some theoretical results and the current status of the work on a prototype plant for the Tritium cycle of compact high-field tokamaks (such as, Ignitor, CIT, etc.), using the SAES Getter St 707 getter material, are described in this report. The schematics and present status of the main subplants of the cycle are reported together with some experimental results demostrating the possibility of utilizing the St 707 material to purify the inert atmosphere of the glove-boxes and the secondary containment of the double-containment metal canalization which is to eventually house the various parts of the plant. Finally, as an example, the FTU machine, under construction at ENEA Frascati, has been taken as a reference, and theoretical evaluations are given for the inventory, permeation and release of the Tritium from the first wall and the thermal shieldes of such a tokamak

  11. High field optical nonlinearities in gases

    Science.gov (United States)

    Cheng, Yu-Hsiang

    Optical femtosecond self-channeling in gases, also called femtosecond filamentation, has become an important area of research in high field nonlinear optics. Filamentation occurs when laser light self-focuses in a gas owing to self-induced nonlinearity, and then defocuses in the plasma generated by the self-focused beam. The result of this process repeating itself multiple times is an extended region of plasma formation. Filamentation studies have been motivated by the extremely broad range of applications, especially in air, including pulse compression, supercontinuum generation, broadband high power terahertz pulse generation, discharge triggering and guiding, and remote sensing. Despite the worldwide work in filamentation, the fundamental gas nonlinearities governing self-focusing had never been directly measured in the range of laser intensity up to and including the ionization threshold. This dissertation presents the first such measurements. We absolutely measured the temporal refractive index change of O2, N2, Ar, H2, D2 and N2O caused by highfield ultrashort optical pulses with single-shot supercontinuum spectral interferometry, cleanly separating for the first time the instantaneous electronic and delayed rotational nonlinear response in diatomic gases. We conclusively showed that a recent claim by several European groups that the optical bound electron nonlinearity saturates and goes negative is not correct. Such a phenomenon would preclude the need for plasma to provide the defocusing contribution for filamentation. Our results show that the 'standard model of filamentation', where the defocusing is provided by plasma, is correct. Finally, we demonstrated that high repetition rate femtosecond laser pulses filamenting in gases can generate long-lived gas density `holes' which persist on millisecond timescales, long after the plasma has recombined. Gas density decrements up to ~20% have been measured. The density hole refilling is dominated by thermal

  12. Flow field investigation in a bulb turbine diffuser

    Science.gov (United States)

    Pereira, M.; Duquesne, P.; Aeschlimann, V.; Deschênes, C.

    2017-04-01

    An important drop in turbine performances has been measured in a bulb turbine model operated at overload. Previous investigations have correlated the performance drop with diffuser losses, and particularly to the flow separation zone at the diffuser wall. The flow has been investigated in the transition part of the diffuser using two LDV measurement sections. The transition part is a diffuser section that transforms from a circular to a rectangular section. The two measurement sections are at the inlet and outlet of the diffuser transition part. The turbine has been operated at three operating points, which are representative of different flow patterns at the diffuser exit at overload. In addition to the average velocity field, the analysis is conducted based on a backflow occurrence function and on the swirl level. Results reveal a counter-rotating zone in the diffuser, which intensifies with the guide vanes opening. The guide vanes opening induces a modification of the flow phenomena: from a central backflow recirculation zone at the lowest flowrate to a backflow zone induced by flow separation at the wall at the highest flowrate.

  13. Generating highly uniform electromagnetic field characteristics

    Science.gov (United States)

    Crow, James T.

    1998-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  14. High-Gain High-Field Fusion Plasma

    Science.gov (United States)

    Li, Ge

    2015-01-01

    A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST. PMID:26507314

  15. Strong-field relativistic processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Postavaru, Octavian

    2010-12-08

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part, we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic phenomena and nuclear effects by applying coherent light with x-ray frequencies. Atomic dipole or multipole moments may be determined to unprecedented accuracy by measuring the interference-narrowed fluorescence spectrum. Furthermore, we investigate the level structure of heavy hydrogenlike ions in laser beams. Interaction with the light field leads to dynamic shifts of the electronic energy levels, which is relevant for spectroscopic experiments. We apply a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the dipole approximation and takes into account non-dipole effects of retardation and interaction with the magnetic field components of the laser beam. We predicted cross sections for the inter-shell trielectronic recombination (TR) and quadruelectronic recombination processes which have been experimentally confirmed in electron beam ion trap measurements, mainly for C-like ions, of Ar, Fe and Kr. For Kr{sup 30}+, inter-shell TR contributions of nearly 6% to the total resonant photorecombination rate were found. (orig.)

  16. Syntheses, X-ray structures, solid state high-field electron paramagnetic resonance, and density-functional theory investigations on chloro and aqua Mn(II) mononuclear complexes with amino-pyridine pentadentate ligands.

    Science.gov (United States)

    Hureau, Christelle; Groni, Sihem; Guillot, Régis; Blondin, Geneviève; Duboc, Carole; Anxolabéhère-Mallart, Elodie

    2008-10-20

    The two pentadentate amino-pyridine ligands L5(2) and L5(3) (L5(2) and L5(3) stand for the N-methyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine and the N-methyl-N,N',N'-tris(2-pyridylmethyl)propane-1,3-diamine, respectively) were used to synthesize four mononuclear Mn(II) complexes, namely [(L5(2))MnCl](PF6) (1(PF6)), [(L5(3))MnCl](PF6) (2(PF6)), [(L5(2))Mn(OH2)](BPh4)2 (3(BPh4)2), and [(L5(3))Mn(OH2)](BPh4)2 (4(BPh4)2). The X-ray diffraction studies revealed different configurations for the ligand L5(n) (n = 2, 3) depending on the sixth exogenous ligand and/or the counterion. Solid state high-field electron paramagnetic resonance spectra were recorded on complexes 1-4 as on previously described mononuclear Mn(II) systems with tetra- or hexadentate amino-pyridine ligands. Positive and negative axial zero-field splitting (ZFS) parameters D were determined whose absolute values ranged from 0.090 to 0.180 cm(-1). Density-functional theory calculations were performed unraveling that, in contrast with chloro systems, the spin-spin and spin-orbit coupling contributions to the D-parameter are comparable for mixed N,O-coordination sphere complexes.

  17. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 1: Remedial investigation results

    International Nuclear Information System (INIS)

    Yuen, C. R.; Martino, L. E.; Biang, R. P.; Chang, Y. S.; Dolak, D.; Van Lonkhuyzen, R. A.; Patton, T. L.; Prasad, S.; Quinn, J.; Rosenblatt, D. H.; Vercellone, J.; Wang, Y. Y.

    2000-01-01

    This report presents the results of the remedial investigation (RI) conducted at J-Field in the Edgewood Area of Aberdeen Proving Ground (APG), a U.S. Army installation located in Harford County, Maryland. Since 1917, activities in the Edgewood Area have included the development, manufacture, and testing of chemical agents and munitions and the subsequent destruction of these materials at J-Field by open burning and open detonation. These activities have raised concerns about environmental contamination at J-Field. This RI was conducted by the Environmental Conservation and Restoration Division, Directorate of Safety, Health and Environmental Division of APG, pursuant to requirements outlined under the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (CERCLA). The RI was accomplished according to the procedures developed by the U.S. Environmental Protection Agency (EPA 1988). The RI provides a comprehensive evaluation of the site conditions, nature of contaminants present, extent of contamination, potential release mechanisms and migration pathways, affected populations, and risks to human health and the environment. This information will be used as the basis for the design and implementation of remedial actions to be performed during the remedial action phase, which will follow the feasibility study (FS) for J-Field

  18. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 1: Remedial investigation results

    Energy Technology Data Exchange (ETDEWEB)

    Yuen, C. R.; Martino, L. E.; Biang, R. P.; Chang, Y. S.; Dolak, D.; Van Lonkhuyzen, R. A.; Patton, T. L.; Prasad, S.; Quinn, J.; Rosenblatt, D. H.; Vercellone, J.; Wang, Y. Y.

    2000-03-14

    This report presents the results of the remedial investigation (RI) conducted at J-Field in the Edgewood Area of Aberdeen Proving Ground (APG), a U.S. Army installation located in Harford County, Maryland. Since 1917, activities in the Edgewood Area have included the development, manufacture, and testing of chemical agents and munitions and the subsequent destruction of these materials at J-Field by open burning and open detonation. These activities have raised concerns about environmental contamination at J-Field. This RI was conducted by the Environmental Conservation and Restoration Division, Directorate of Safety, Health and Environmental Division of APG, pursuant to requirements outlined under the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (CERCLA). The RI was accomplished according to the procedures developed by the U.S. Environmental Protection Agency (EPA 1988). The RI provides a comprehensive evaluation of the site conditions, nature of contaminants present, extent of contamination, potential release mechanisms and migration pathways, affected populations, and risks to human health and the environment. This information will be used as the basis for the design and implementation of remedial actions to be performed during the remedial action phase, which will follow the feasibility study (FS) for J-Field.

  19. Investigation of rootzone salinity with field monitoring system at tsunami affected rice fields in Miyagi, Japan

    OpenAIRE

    Tokumoto, Ieyasu; Chiba, Katsumi; Mizoguchi, Masaru; Miyamoto, Hideki

    2016-01-01

    After the 2011 Tohoku earthquake, thirteen thousand hectares of farmlands were damaged by massive Tsunami near coastal sites in Miyagi, Japan. Some eighty percent of the damaged farmlands have been recovered in 2014, but subsidence and high salinity groundwater make it difficult to completely remove salinity from the soil. To solve the problem, management of saltwater intrusion plays an important role in rootzone salinity control with the Field Monitoring System (FMS), which is remote sensing...

  20. High magnetic field ohmically decoupled non-contact technology

    Science.gov (United States)

    Wilgen, John [Oak Ridge, TN; Kisner, Roger [Knoxville, TN; Ludtka, Gerard [Oak Ridge, TN; Ludtka, Gail [Oak Ridge, TN; Jaramillo, Roger [Knoxville, TN

    2009-05-19

    Methods and apparatus are described for high magnetic field ohmically decoupled non-contact treatment of conductive materials in a high magnetic field. A method includes applying a high magnetic field to at least a portion of a conductive material; and applying an inductive magnetic field to at least a fraction of the conductive material to induce a surface current within the fraction of the conductive material, the surface current generating a substantially bi-directional force that defines a vibration. The high magnetic field and the inductive magnetic field are substantially confocal, the fraction of the conductive material is located within the portion of the conductive material and ohmic heating from the surface current is ohmically decoupled from the vibration. An apparatus includes a high magnetic field coil defining an applied high magnetic field; an inductive magnetic field coil coupled to the high magnetic field coil, the inductive magnetic field coil defining an applied inductive magnetic field; and a processing zone located within both the applied high magnetic field and the applied inductive magnetic field. The high magnetic field and the inductive magnetic field are substantially confocal, and ohmic heating of a conductive material located in the processing zone is ohmically decoupled from a vibration of the conductive material.

  1. Magnetic field structure of experimental high beta tokamak equilibria

    International Nuclear Information System (INIS)

    Deniz, A.V.

    1986-01-01

    The magnetic field structure of several low and high β tokamaks in the Columbia High Beta Tokamak (HBT) was determined by high-impedance internal magnetic probes. From the measurement of the magnetic field, the poloidal flux, toroidal flux, toroidal current, and safety factor are calculated. In addition, the plasma position and cross-sectional shape are determined. The extent of the perturbation of the plasma by the probe was investigated and was found to be acceptably small. The tokamaks have major radii of approx.0.24 m, minor radii of approx.0.05 m, toroidal plasma current densities of approx.10 6 A/m 2 , and line-integrated electron densities of approx.10 20 m -2 . The major difference between the low and high β tokamaks is that the high β tokamak was observed to have an outward shift in major radius of both the magnetic center and peak of the toroidal current density. The magnetic center moves inward in major radius after 20 to 30 μsec, presumably because the plasma maintains major radial equilibrium as its pressure decreases from radiation due to impurity atoms. Both the equilibrium and the production of these tokamaks from a toroidal field stabilized z-pinch are modeled computationally. One tokamak evolves from a state with low β features, through a possibly unstable state, to a state with high β features

  2. Field site investigation: Effect of mine seismicity on groundwater hydrology

    International Nuclear Information System (INIS)

    Ofoegbu, G.I.; Hsiung, S.; Chowdhury, A.H.

    1995-04-01

    The results of a field investigation on the groundwater-hydrologic effect of mining-induced earthquakes are presented in this report. The investigation was conducted at the Lucky Friday Mine, a silver-lead-zinc mine in the Coeur d'Alene Mining District of Idaho. The groundwater pressure in sections of three fracture zones beneath the water table was monitored over a 24-mo period. The fracture zones were accessed through a 360-m-long inclined borehole, drilled from the 5,700 level station of the mine. The magnitude, source location, and associated ground motions of mining-induced seismic events were also monitored during the same period, using an existing seismic instrumentation network for the mine, augmented with additional instruments installed specifically for the project by the center for Nuclear Waste Regulatory Analyses (CNWRA). More than 50 seismic events of Richter magnitude 1.0 or larger occurred during the monitoring period. Several of these events caused the groundwater pressure to increase, whereas a few caused it to decrease. Generally, the groundwater pressure increased as the magnitude of seismic event increased; for an event of a given magnitude, the groundwater pressure increased by a smaller amount as the distance of the observation point from the source of the event increased. The data was examined using regression analysis. Based on these results, it is suggested that the effect of earthquakes on groundwater flow may be better understood through mechanistic modeling. The mechanical processes and material behavior that would need to be incorporated in such a model are examined. They include a description of the effect of stress change on the permeability and water storage capacity of a fracture rock mass; transient fluid flow; and the generation and transmission of seismic waves through the rock mass

  3. Geoelectromagnetic and geothermic investigations in the Ihlara Valley geothermal field

    Science.gov (United States)

    İlkişik, O. Metin; Gürer, Aysan; Tokgöz, Tuǧrul; Kaya, Cemal

    1997-09-01

    The Ihlara Valley is situated within a volcanic arc that is formed by the collision of the eastern Mediterranean plate system with the Anatolian plate. In this study we will present data from a reservoir monitoring project over the Ihlara-Ziga geothermal field, located 22 km east of Aksaray, in central Anatolia. Although identified geothermal resources in the Ihlara Valley are modest, substantial undiscovered fields have been inferred primarily from the volcanic and tectonic setting but also from the high regional heat flow (150-200 mWm -2) on the Kirşehir Massif. In 1988 and 1990, geoelectromagnetic surveys were undertaken by MTA-Ankara to confirm the presence of a relatively shallow (≈ 0.5-1 km), hydrothermally caused conductive layer or zone. CSAMT and Schlumberger resistivity data show good correspondence with each other, and 2-D geoelectric models are also in harmony with geologic data and gravity anomalies. The depth of the resistive basement, which is interpreted as Paleozoic limestone, is 200-250 m in the western part and increases eastward (≈ 600-750 m). This may imply N-S-oriented normal faulting within the survey area. The parameters of the top layer are a resistivity of 25 to 95 ohm m and a thickness of between 100 and 250 m. The thickness of the conductive tuffs between the top layer and the basement, whose resistivity is about 4-5 o hmm, also increases eastward (from 100 to 450 m). The apparent resistivity maps for the frequencies between 32 and 2 Hz reveal a localized low resistivity anomaly to the east of Belisirma.

  4. Ecological investigation of application of pesticides in rice fields

    International Nuclear Information System (INIS)

    Nouri, J.; Arjomandi, R.; Bayat, H.

    2000-01-01

    Among several pests of rice as one of the main agricultural products in Iran, rice borer, C hilo sarsaparilla is one of the most important pests of this crop. Use of pesticides coincided with the occurrence of this pest in the northern region of Iran in 1972. At present in order to control this pest, more than 12000 tones of pesticides granules are used annually. Ecological effects of pesticides application and the use of Trichograma sp. as a natural enemy, for assessing the impacts of pesticides in environments, especially on different living organisms on the plant, in irrigation water, and in 5 cm depth of surface soil, were investigated in two regions of Amol, named Osk. Mahalleh and Capik Field of Tashbandan. Results indicated that the two treatments were not different on crop loss. One the contrary, in the pesticide treatment, there was a considerable dec tease in the population of living organisms, particularly, no organism was observed in 5 cm depth of surface soil. It is recommended that in order to maintain the balance of environment, the use of chemicals for controlling rice borer must be with extreme care, only in the inevitable was with the use of principles of Integrated Pest Management

  5. Magnetic resonance imaging and spectroscopy at ultra high fields

    International Nuclear Information System (INIS)

    Neuberger, Thomas

    2009-01-01

    The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

  6. Magnetic resonance imaging and spectroscopy at ultra high fields

    Energy Technology Data Exchange (ETDEWEB)

    Neuberger, Thomas

    2009-06-23

    The goal of the work presented in this thesis was to explore the possibilities and limitations of MRI / MRS using an ultra high field of 17.6 tesla. A broad range of specific applications and MR methods, from MRI to MRSI and MRS were investigated. The main foci were on sodium magnetic resonance spectroscopic imaging of rodents, magnetic resonance spectroscopy of the mouse brain, and the detection of small amounts of iron labeled stem cells in the rat brain using MRI Sodium spectroscopic imaging was explored since it benefits tremendously from the high magnetic field. Due to the intrinsically low signal in vivo, originating from the low concentrations and short transverse relaxation times, only limited results have been achieved by other researchers until now. Results in the literature include studies conducted on large animals such as dogs to animals as small as rats. No studies performed on mice have been reported, despite the fact that the mouse is the most important laboratory animal due to the ready availability of transgenic strains. Hence, this study concentrated on sodium MRSI of small rodents, mostly mice (brain, heart, and kidney), and in the case of the brain on young rats. The second part of this work concentrated on proton magnetic resonance spectroscopy of the rodent brain. Due to the high magnetic field strength not only the increasing signal but also the extended spectral resolution was advantageous for such kind of studies. The difficulties/limitations of ultra high field MRS were also investigated. In the last part of the presented work detection limits of iron labeled stem cells in vivo using magnetic resonance imaging were explored. The studies provided very useful benchmarks for future researchers in terms of the number of labeled stem cells that are required for high-field MRI studies. Overall this work has shown many of the benefits and the areas that need special attention of ultra high fields in MR. Three topics in MRI, MRS and MRSI were

  7. Investigation of Axial Electric Field Measurements with Grounded-Wire TEM Surveys

    Science.gov (United States)

    Zhou, Nan-nan; Xue, Guo-qiang; Li, Hai; Hou, Dong-yang

    2018-01-01

    The grounded-wire transient electromagnetic (TEM) surveying is often performed along the equatorial direction with its observation lines paralleling to the transmitting wire with a certain transmitter-receiver distance. However, such method takes into account only the equatorial component of the electromagnetic field, and a little effort has been made on incorporating the other major component along the transmitting wire, here denoted as axial field. To obtain a comprehensive understanding of its fundamental characteristics and guide the designing of the corresponding observation system for reliable anomaly detection, this study for the first time investigates the axial electric field from three crucial aspects, including its decay curve, plane distribution, and anomaly sensitivity, through both synthetic modeling and real application to one major coal field in China. The results demonstrate a higher sensitivity to both high- and low-resistivity anomalies by the electric field in axial direction and confirm its great potentials for robust anomaly detection in the subsurface.

  8. Experimental and field investigations on uprooting of riparian vegetation

    Science.gov (United States)

    Calvani, Giulio; Francalanci, Simona; Solari, Luca; Gumiero, Bruna

    2017-04-01

    The morphology of a river reach is the result of many processes involving the motion of sediment (erosion, transport and deposition), the hydrological regime and the development and growth of vegetation. River evolution in the presence of vegetation depends on establishment of pioneer woody riparian seedlings on bars, and consequently on either their survival or death. Flooding events can cause young vegetation mortality by uprooting (Corenblit et al., 2007). These processes, despite their important implications on river morphodynamics, have been poorly investigated in the past. Most of previous research focused on the mechanism of root breakage and on measuring the vegetation resistance to uprooting in the vertical direction, while few works considered the effect of flow direction on the uprooting process (Bywater-Reyes et al., 2015). In this work, we focused on vegetation uprooting due to flow and to bed erosion. We considered two different types of vegetation: Avena Sativa, grown from seeds in external boxes, was used to investigate instantaneous uprooting, and Salix Purpurea, collected in the field, for delayed uprooting (namely type I and type II mechanisms, according to Edmaier et al., 2011). The experiments were carried out in a 5 m long flume in the Hydraulic Laboratory in Florence. A 2 m long mobile bed was build inside the flume, and vegetation was arranged according to several configurations on it. Both types of vegetation were subject to constant discharges to investigate the effects of a general bed degradation in modifying the occurrence of uprooting. We also performed some experiments with Avena Sativa located in a fixed bed and subjected to an increasing flow discharge in order to simulate instantaneous uprooting due to the action of hydrodynamic forces. We measured flow velocity, flow discharge and water depth and characterized vegetation by stem and root diameter, height and root length. The experimental results have been interpreted in terms of a

  9. Superconducting niobium in high rf magnetic fields

    International Nuclear Information System (INIS)

    Mueller, G.

    1988-01-01

    The benefit of superconducting cavities for accelerator applications depends on the field and Q/sub 0/ levels which can be achieved reliably in mass producible multicell accelerating structures. The presently observed field and Q/sub 0/ limitations are caused by anomalous loss mechanisms which are not correlated with the intrinsic properties of the pure superconductor but rather due to defects or contaminants on the superconducting surface. The ultimate performance levels of clean superconducting cavities built from pure Nb will be given by the rf critical field and the surface resistance of the superconductor. In the first part of this paper a short survey is given of the maximum surface magnetic fields achieved in single-cell cavities. The results of model calculations for the thermal breakdown induced by very small defects and for the transition to the defect free case is discussed in part 2. In the last chapter, a discussion is given for the rf critical field of Nb on the basis of the Ginzburg-Landau Theory. It is shown that not only purity but also the homogeneity of the material should become important for the performance of superconducting Nb cavities at field levels beyond 100mT. Measurement results of the upper critical field for different grades of commercially available Nb sheet materials are given. 58 references, 20 figures, 1 table

  10. National High Magnetic Field Laboratory (NHMFL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Pulsed Field Program is located in Northern New Mexico at Los Alamos National Laboratory. The user program is designed to provide researchers with a balance of...

  11. On the Method of Investigating Human Exposure to Nonuniform Magnetic Field

    Science.gov (United States)

    Yamazaki, Kenichi; Kawamoto, Tadashi; Fujinami, Hideo; Shigemitsu, Tsukasa

    Regarding compliance testing with existing guidelines on human exposure to ELF (extremely low frequency) magnetic fields, the nonuniformity of the fields has been one of the major concerns since guideline-level exposures are generally encountered in the direct vicinity of magnetic field sources such as electric power facilities and electric appliances. According to the guidelines, when the measured maximum magnetic fields exceed the specified field level, induced currents inside human bodies are to be investigated to check their conformity. However, this calculation still needs verification and requires massive computational resources, which are not readily applicable under practical exposure conditions. Therefore, a simple and relevant method of assessing nonuniform magnetic field exposure is highly desirable. In this paper, a method of obtaining an equivalent uniform magnetic field using a coefficient (the normalized induction factor) is investigated using a numerical calculation of induced current in anatomically correct human models. In addition, to assess the obtained coefficient easily, a simple method using a spherical model was proposed.

  12. Investigation of Magnetic Field in the Subway Station

    Directory of Open Access Journals (Sweden)

    Ctibor Henzl

    2006-01-01

    Full Text Available Paper deals with computing of magnetic field in the rails surroundings of subway (underground. The calculation of field is made by using of an analytical method in Excel VBA. There is also used commercial FEM software ANSYS and finite element method. Output results of the both methods are finally compared.

  13. Investigations on magnetic field induced optical transparency in magnetic nanofluids

    Science.gov (United States)

    Mohapatra, Dillip Kumar; Philip, John

    2018-02-01

    We study the magnetic field induced optical transparency and its origin in magnetic nanoemulsion of droplets of average size ∼200 nm containing superparamagnetic iron oxide nanoparticles. Beyond a certain volume fraction (Φ > 0.0021) of magnetic nanoemulsion and a critical magnetic field (Hc1), the transmitted light intensity increases drastically and reaches a maximum at another critical magnetic field (Hc2), beyond which the transmitted light intensity decreases and reaches a plateau. Interestingly, the transmitted light intensity at Hc2 is found to increase linearly with Φ and the critical magnetic fields Hc1 and Hc2 follow power law decay with Φ (i.e. Hc ∼ Φ-x), with exponents 0.48 and 0.27, respectively. The light intensity recovers to its initial value when the magnetic field is switched off, indicating the perfect reversibility of the field induced transparency process. The observed straight line scattered patterns above Hc2, on a screen placed perpendicular to the incident beam, confirms the formation of rod like anisotropic nanostructures perpendicular to the direction of light propagation. The magneto-optical measurements in the emulsion confirm that the observed field induced transparency in magnetic emulsions for Φ > 0.0021 is due to the optical birefringence caused by the rod like nanostructures. The reduced birefringence is found to be proportional to the square of the applied magnetic field. This finding offers several possibilities in using magnetic nanofluids in tunable optical devices.

  14. High-Field Superconducting Magnets Supporting PTOLEMY

    Science.gov (United States)

    Hopkins, Ann; Luo, Audrey; Osherson, Benjamin; Gentile, Charles; Tully, Chris; Cohen, Adam

    2013-10-01

    The Princeton Tritium Observatory for Light, Early Universe, Massive Neutrino Yield (PTOLEMY) is an experiment planned to collect data on Big Bang relic neutrinos, which are predicted to be amongst the oldest and smallest particles in the universe. Currently, a proof-of-principle prototype is being developed at Princeton Plasma Physics Laboratory to test key technologies associated with the experiment. A prominent technology in the experiment is the Magnetic Adiabatic Collimation with an Electrostatic Filter (MAC-E filter), which guides tritium betas along magnetic field lines generated by superconducting magnets while deflecting those of lower energies. B field mapping is performed to ensure the magnets produce a minimum field at the midpoint of the configuration of the magnets and to verify accuracy of existing models. Preliminary tests indicate the required rapid decrease in B field strength from the bore of the more powerful 3.35 T magnet, with the field dropping to 0.18 T approximately 0.5 feet from the outermost surface of the magnet.

  15. An investigation of singular Lagrangians as field systems

    International Nuclear Information System (INIS)

    Rabei, E.M.

    1995-07-01

    The link between the treatment of singular Lagrangians as field systems and the general approach is studied. It is shown that singular Lagrangians as field systems are always in exact agreement with the general approach. Two examples and the singular Lagrangian with zero rank Hessian matrix are studied. The equations of motion in the field systems are equivalent to the equations which contain acceleration, and the constraints are equivalent to the equations which do not contain acceleration in the general approach treatment. (author). 10 refs

  16. Apparatus for ground water chemistry investigations in field caissons

    International Nuclear Information System (INIS)

    Cokal, E.J.; Stallings, E.; Walker, R.; Nyhan, J.W.; Polzer, W.L.; Essington, E.H.

    1985-01-01

    Los Alamos is currently in its second season of ground water chemistry and hydrology experimentation in a field facility that incorporates clusters of six, 3-meter-diameter by 6-meter-deep, soil-filled caissons and required ancillaries. Initial experience gained during the 1983 field season indicated the need for further development of the technology of this type of experimentation supporting hydrologic waste management research. Uniform field application of water/matrix solutions to the caisson, matrix and tracer solution blending/storage, and devices for ground water sampling are discussed

  17. Investigation of field temperature in moulds of foamed plaster

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2007-12-01

    Full Text Available Plaster moulds used in precision foundry are characterized by a very low permeability which, in the case of classic plaster moulds, equals to about 0,01÷0,02 m2/(MPa·s. One of the most effective methods for increasing the permeability is a foaming treatment. Another characteristic feature of plaster is its very good insulating power which has influence on the process of solidification and cooling of a cast and also on a knock-out property. This insulating power is a function of thermophysical properties of plaster which, in turn, depend mainly on the mineralogical composition of the mould material, its bulk density as well as on the temperature of the pouring alloy. In the case of a foamed plaster mould an increase of the degree of foaming increases its porosity which causes a change in its thermophysical properties, thereby increasing susceptibility of the mass to overheating. The susceptibility of the plaster layer surrounding the cast to overheating is favorable because it makes it easier to knock-out of the cast by immersing the hot mould in cold water. Thermal and phase tensions that are created during this process cause fast destruction of plaster. This paper describes our investigations aimed at the determination of the dependence of the mould temperature field on the time of the cast stay in the mould, as recorded in a process of an unsteady heat flow. The determined data were planned to be used for estimation of the technological properties of the plaster mould. The tests were carried out using the plaster α-Supraduro and Alkanol XC (foaming agent. The test mould had a diameter of Ø 120 mm with centrally situated mould cavity of Ø 30 mm. Plaster moulds with a degree of foaming 20; 32,5 and 45% and comparatively from non-foaming plaster were tested and their temperatures were measured at the distance x=2; 9; 21; 25;27; 30 mm from the mould cavity within 25 min. Analysis of the results leads to the conclusion, that the highest

  18. Policy Forum: Studying Eyewitness Investigations in the Field

    Science.gov (United States)

    Dawes, Robyn; Jacoby, Larry L.; Kahneman, Daniel; Lempert, Richard; Roediger, Henry L.; Rosenthal, Robert

    2007-01-01

    This article considers methodological issues arising from recent efforts to provide field tests of eyewitness identification procedures. We focus in particular on a field study (Mecklenburg 2006) that examined the “double blind, sequential” technique, and consider the implications of an acknowledged methodological confound in the study. We explain why the confound has severe consequences for assessing the real-world implications of this study. PMID:17610149

  19. Investigation of the Periodic Magnetic Field Modulation Inside Apertures of LHC Superconducting Dipole Models

    CERN Document Server

    Pugnat, P; Siemko, A

    2000-01-01

    The windings of high-field accelerator magnets are usually made of Rutherford-type superconducting cables. The magnetic field distribution along the axis of such magnets exhibits a pronounced periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. Such an effect, resulting from quasi-persistent currents, was investigated with a Hall probe array inserted inside the aperture of 1-metre long LHC superconducting dipole models. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the transport current history. The impact on the magnet stability of the non-uniform current redistribution producing such a field modulation is discussed.

  20. Seasonal dependence of high-latitude electric fields

    International Nuclear Information System (INIS)

    de la Beaujardiere, O.; Leger, C.; Alcayde, D.; Fontanari, J.

    1991-01-01

    The seasonal dependence of the high-latitude electric field was investigated using Sondrestrom incoherent scatter radar data. Average ExB drifts were derived from 5 years of measurements centered around solar minimum. The electrostatic potentials that best fit the observed average electric field were calculated. It was found that the large-scale convection pattern significantly changes with season. This change involves the overall shape of the convection pattern, as well as the electric field intensity, and thus the total dawn-dusk potential across the polar cap. The cross polar cap potential drop is largest in fall, followed by winter, spring and summer. The small difference found between the summer and winter cross polar cap potential can be attributed to differing field-aligned potential drops. In view of the well-known relationship between field-aligned currents and parallel potential drop, this is consistent with the observations that Birkeland currents are larger in the summer than in winter. Changes in the overall shape of the convection pattern are consistent with the simple notion that the whole pattern is shifted toward the nightside as well as, to a lesser extent, toward the dawnside in summer as compared to winter. This assumption is based on the following observed effects: (1) The rotation of the overall convection pattern toward earlier local times with respect to the noon-midnight direction is maximum for summer on the dayside. (2) On the nightside, the Harang discontinuity is typically located within the radar field of view (Λ=67 to 82) in the winter averaged patterns, but it is equatorward of the field of view in summer. (3) The line that joins the dawn and dusk potential maxima is shifted toward the midnight sector in summer as compared to winter by about 5 degree. (4) In the dawn cell, the latitude of the convection reversal is the lowest during summer; in the dusk cell the latitude of the reversal is the lowest during winter

  1. Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, R Michael [Remote Measurements & Research Company, Seattle, WA (United States); Lewis, Ernie [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-09-01

    One of the most critical measurements in the suite of meteorological measurements used for the calculation of evaporation and latent heat flux is the relative humidity (RH). In order to achieve an overall net flux uncertainty < 10 W/m2 (Bradley and Fairall, 2006), the RH must be accurate to < 2 %RH. Anyone experienced in shipboard meteorological measurements will recognize that this is a tough specification. During the U.S. Department of Energy (DOE) Marine Atmospheric Radiation Measurement (ARM) Climate Research Facility Global Energy and Water Experiment (GEWEX) Cloud System Study (GCSS) Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds (MAGIC) experiment, the meteorological package used three different RH sensors. We found approximately 3-4 % differences between units. To arbitrate the differences and to track calibration drift over the months of exposure, we used a precision psychrometer. The Assmann Psychrometer, Model 430101 is a classic, mercury-in-glass instrument that gives a precise measure of the wet and dry bulb temperatures from which atmospheric humidity and RH are computed. On a regular basis, typically after each balloon launch, a technician took the psychrometer to an exposed location on the bridge roof. That was just below the instruments on the mast and high enough into the mixed layer that the difference is negligible.

  2. High Field Magnetization of Tb Single Crystals

    DEFF Research Database (Denmark)

    Roeland, L. W.; Cock, G. J.; Lindgård, Per-Anker

    1975-01-01

    The magnetization of Tb single crystals was measured in magnetic fields to 34T along the hard direction at temperature of 1.8, 4.2, 65.5 and 77K, and along with easy direction at 4.2 and 77K. The data are compared with the results of a self-consistent spin wave calculation using a phenomenological...

  3. Inversion layer thermopower in high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Girvin, S.M.; Jonson, M.

    1982-11-20

    The authors calculate the thermopower of an ideal two-dimensional electron gas (inversion layer) in a quantising magnetic field. They find that the thermopower is a universal function of the reduced temperature which has a novel dependence on the chemical potential.

  4. Moderate and high intensity pulsed electric fields

    NARCIS (Netherlands)

    Timmermans, Rian Adriana Hendrika

    2018-01-01

    Pulsed Electric Field (PEF) processing has gained a lot of interest the last decades as mild processing technology as alternative to thermal pasteurisation, and is suitable for preservation of liquid food products such as fruit juices. PEF conditions typically applied at industrial scale for

  5. Plasma instabilities in high electric fields

    DEFF Research Database (Denmark)

    Morawetz, K.; Jauho, Antti-Pekka

    1994-01-01

    expression is derived for the nonequilibrium dielectric function epsilon(K, omega). For certain values of momenta K and frequency omega, Imepsilon(K, omega) becomes negative, implying a plasma instability. This new instability exists only for strong electric fields, underlining its nonequilibrium origin....

  6. High magnetic field induced otolith fusion in the zebrafish larvae.

    Science.gov (United States)

    Pais-Roldán, Patricia; Singh, Ajeet Pratap; Schulz, Hildegard; Yu, Xin

    2016-04-11

    Magnetoreception in animals illustrates the interaction of biological systems with the geomagnetic field (geoMF). However, there are few studies that identified the impact of high magnetic field (MF) exposure from Magnetic Resonance Imaging (MRI) scanners (>100,000 times of geoMF) on specific biological targets. Here, we investigated the effects of a 14 Tesla MRI scanner on zebrafish larvae. All zebrafish larvae aligned parallel to the B0 field, i.e. the static MF, in the MRI scanner. The two otoliths (ear stones) in the otic vesicles of zebrafish larvae older than 24 hours post fertilization (hpf) fused together after the high MF exposure as short as 2 hours, yielding a single-otolith phenotype with aberrant swimming behavior. The otolith fusion was blocked in zebrafish larvae under anesthesia or embedded in agarose. Hair cells may play an important role on the MF-induced otolith fusion. This work provided direct evidence to show that high MF interacts with the otic vesicle of zebrafish larvae and causes otolith fusion in an "all-or-none" manner. The MF-induced otolith fusion may facilitate the searching for MF sensors using genetically amenable vertebrate animal models, such as zebrafish.

  7. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  8. Novel Electrochemical Phenomena in Magnetic Fields(Research in High Magnetic Fields)

    OpenAIRE

    Mogi, Iwao; Kamiko, Masao

    1996-01-01

    Recent two topics are given of electrochemical studies in steady magnetic fields at the High Field Laboratory of Tohoku University. One is the magnetic-field-induced diffusion-limited-aggregation in the pattern formation of silver electrodeposits . The other is the magnetic field effect on the learning effect in a dopant-exchange process of an organic conducting polymer polypyrrole.

  9. Flatland Electrons in High Magnetic Fields

    Science.gov (United States)

    Shayegan, M.

    This paper provides a review of recent developments in the physics of two-dimensional carrier systems in perpendicular magnetic fields. The emphasis is on many-body phenomena in very clean GaAs/AlGaAs heterostructures, probed via magnetotransport measurements. Topics that are discussed include the integer and fractional quantum Hall effects, Wigner crystallization, composite Fermions, Skyrmions, stripe and bubble phases in single layer systems, and electron-hole pairing and Bose-Einstein condensation in interacting bilayer systems.

  10. Microdevices for Investigating Pulsed Electric Fields-Mediated Therapies at Cellular and Tissue Level

    OpenAIRE

    Bonakdar, Mohammad

    2016-01-01

    Recent attempts to investigate living systems from a biophysical point of view has opened new windows for development of new diagnostic methods and therapies. Pulsed electric fields (PEFs) are a new class of therapies that take advantage of biophysical properties and have proven to be effective in drug delivery and treating several disorders including tumors. While animal models are commonly being used for development of new therapies, the high cost and complexity of these models along with t...

  11. Highly Cited Soviet Papers: An Exploratory Investigation.

    Science.gov (United States)

    Narin, Fransic; And Others

    1983-01-01

    The bibliographic methodology of citation tabulation was applied to the problem of identifying highly cited Soviet scientific papers (in Science Citation Index). Findings indicate that lists generated are indicative of areas of strong Soviet research and that institutions producing these papers include the most important Soviet labs. (Author/JN)

  12. Experimental extreme field strength investigation in reverberant enclosures

    NARCIS (Netherlands)

    Vogt-Ardatjew, R.A.; van de Beek, G.S.; Leferink, Frank Bernardus Johannes

    2014-01-01

    The field strength distribution in real reverberant enclosures, such as plane fuselages or factory interiors, is often too complex for a deterministic approach but can also fall into a category where theoretical assumptions normal for perfect cavities no longer hold. It can vary a lot depending on

  13. Extending methods: using Bourdieu's field analysis to further investigate taste

    Science.gov (United States)

    Schindel Dimick, Alexandra

    2015-06-01

    In this commentary on Per Anderhag, Per-Olof Wickman and Karim Hamza's article Signs of taste for science, I consider how their study is situated within the concern for the role of science education in the social and cultural production of inequality. Their article provides a finely detailed methodology for analyzing the constitution of taste within science education classrooms. Nevertheless, because the authors' socially situated methodology draws upon Bourdieu's theories, it seems equally important to extend these methods to consider how and why students make particular distinctions within a relational context—a key aspect of Bourdieu's theory of cultural production. By situating the constitution of taste within Bourdieu's field analysis, researchers can explore the ways in which students' tastes and social positionings are established and transformed through time, space, place, and their ability to navigate the field. I describe the process of field analysis in relation to the authors' paper and suggest that combining the authors' methods with a field analysis can provide a strong methodological and analytical framework in which theory and methods combine to create a detailed understanding of students' interest in relation to their context.

  14. Comparative investigation of physiological responses of field-grown ...

    African Journals Online (AJOL)

    The objective of this study was to determine the physiological response of Medicago sativa and Festuca arundinacea to cutting under different water regimes in a semi-arid Mediterranean region. In a field experiment, two cutting intensities were applied under irrigation and under rainfed (water deficit) conditions.

  15. An investigation into the induced electric fields from transcranial magnetic stimulation

    Science.gov (United States)

    Hadimani, Ravi; Lee, Erik; Duffy, Walter; Waris, Mohammed; Siddiqui, Waquar; Islam, Faisal; Rajamani, Mahesh; Nathan, Ryan; Jiles, David; David C Jiles Team; Walter Duffy Collaboration

    Transcranial magnetic stimulation (TMS) is a promising tool for noninvasive brain stimulation that has been approved by the FDA for the treatment of major depressive disorder. To stimulate the brain, TMS uses large, transient pulses of magnetic field to induce an electric field in the head. This transient magnetic field is large enough to cause the depolarization of cortical neurons and initiate a synaptic signal transmission. For this study, 50 unique head models were created from MRI images. Previous simulation studies have primarily used a single head model, and thus give a limited image of the induced electric field from TMS. This study uses finite element analysis simulations on 50 unique, heterogeneous head models to better investigate the relationship between TMS and the electric field induced in brain tissues. Results showed a significant variation in the strength of the induced electric field in the brain, which can be reasonably predicted by the distance from the TMS coil to the stimulated brain. Further, it was seen that some models had high electric field intensities in over five times as much brain volume as other models.

  16. High-field magnetization of dilute rare earths in yttrium

    DEFF Research Database (Denmark)

    Touborg, P.; Høg, J.; Cock, G. J.

    1974-01-01

    Magnetization measurements have been performed on single crystals of Y containing small amounts of Tb, Dy, or Er at 4.2 K in fields up to 295 × 105 A/m (370 kOe). Crystal-field and molecular-field parameters obtained from measurements of the initial susceptibility versus temperature give...... a satisfactory quantitative account of the high-field magnetization. This includes characteristic features due to the crossing and mixing of crystal-field levels....

  17. Investigations on transport and storage of high ion beam intensities

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ninad Shrikrishna

    2009-08-25

    In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson's equation. Further simulations were performed to study the self field effects on beam transport. Experiments were performed to compare the simulation results and gain practical experience. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He{sup +} and mixed p, H{sup 2+}, H{sup 3+} beams were analyzed. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was

  18. Investigations on transport and storage of high ion beam intensities

    International Nuclear Information System (INIS)

    Joshi, Ninad Shrikrishna

    2009-01-01

    In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson's equation. Further simulations were performed to study the self field effects on beam transport. Experiments were performed to compare the simulation results and gain practical experience. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He + and mixed p, H 2+ , H 3+ beams were analyzed. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was designed to perform

  19. Composite conductors for high pulsed magnetic fields

    International Nuclear Information System (INIS)

    Dupouy, F.; Askenazy, S.; Peyrade, J.P.; Legat, D.

    1995-01-01

    In this paper, two kinds of reinforced conductors, with high strength and high conductivity are discussed: stainless steel clad copper wires (σ uts (77 K)=1370 MPa for 50% of stainless steel) and copper wires with 9 million continuous filaments of niobium (σ uts (77 K)=1050 MPa for 25% of niobium; resistivity ratio from 273 to 77 K: 5.43). (orig.)

  20. High-field NMR using resistive and hybrid magnets

    Science.gov (United States)

    Gan, Zhehong; Kwak, Hyung-Tae; Bird, Mark; Cross, Timothy; Gor'kov, Peter; Brey, William; Shetty, Kiran

    2008-03-01

    Resistive and resistive-superconducting hybrid magnets can generate dc magnetic fields much higher than conventional superconducting NMR magnets but the field spatial homogeneity and temporal stability are usually not sufficient for high-resolution NMR experiments. Hardware and technique development addressing these issues are presented for high-resolution NMR at magnetic fields up to 40 T. Passive ferromagnetic shimming and magic-angle spinning are used effectively to reduce the broadening from inhomogeneous magnetic field. A phase correction technique based on simultaneous heteronuclear detection is developed to compensate magnetic field fluctuations to achieve high spectral resolution.

  1. Spectroscopic investigations of high-energy-density\

    Czech Academy of Sciences Publication Activity Database

    Civiš, Martin; Ferus, Martin; Knížek, Antonín; Kubelík, Petr; Kamas, Michal; Španěl, Patrik; Dryahina, Kseniya; Shestivska, Violetta; Juha, Libor; Skřehot, P.; Laitl, V.; Civiš, Svatopluk

    2016-01-01

    Roč. 18, č. 39 (2016), s. 27317-27325 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA14-12010S; GA MŠk LG15013; GA MŠk(CZ) LM2015083 Grant - others:Akademie věd - GA AV ČR(CZ) R200401521 Institutional support: RVO:61388955 ; RVO:68378271 Keywords : HIGH-POWER LASER * INDUCED DIELECTRIC-BREAKDOWN * EARTHS EARLY ATMOSPHERE Subject RIV: CF - Physical ; Theoretical Chemistry; BL - Plasma and Gas Discharge Physics (FZU-D) Impact factor: 4.123, year: 2016

  2. Field investigation of anthelmintic efficacy and risk factors for ...

    African Journals Online (AJOL)

    Urquhart, G.M., Armour, J., Duncan, J.L., Dunn, A.M., Jennings, F.W., 1996. Veterinary Parasitology, pp 19-164. 2nd ed. Blackwell Science. Van Wyk, J.A., Malan, F.S. and Randles, J.L., 1997. How long before resistance makes it impossible to control some field strains of Haemonchus contortus in South Africa with any of the ...

  3. GRACE gravity field modeling with an investigation on correlation between nuisance parameters and gravity field coefficients

    Science.gov (United States)

    Zhao, Qile; Guo, Jing; Hu, Zhigang; Shi, Chuang; Liu, Jingnan; Cai, Hua; Liu, Xianglin

    2011-05-01

    The GRACE (Gravity Recovery And Climate Experiment) monthly gravity models have been independently produced and published by several research institutions, such as Center for Space Research (CSR), GeoForschungsZentrum (GFZ), Jet Propulsion Laboratory (JPL), Centre National d’Etudes Spatiales (CNES) and Delft Institute of Earth Observation and Space Systems (DEOS). According to their processing standards, above institutions use the traditional variational approach except that the DEOS exploits the acceleration approach. The background force models employed are rather similar. The produced gravity field models generally agree with one another in the spatial pattern. However, there are some discrepancies in the gravity signal amplitude between solutions produced by different institutions. In particular, 10%-30% signal amplitude differences in some river basins can be observed. In this paper, we implemented a variant of the traditional variational approach and computed two sets of monthly gravity field solutions using the data from January 2005 to December 2006. The input data are K-band range-rates (KBRR) and kinematic orbits of GRACE satellites. The main difference in the production of our two types of models is how to deal with nuisance parameters. This type of parameters is necessary to absorb low-frequency errors in the data, which are mainly the aliasing and instrument errors. One way is to remove the nuisance parameters before estimating the geopotential coefficients, called NPARB approach in the paper. The other way is to estimate the nuisance parameters and geopotential coefficients simultaneously, called NPESS approach. These two types of solutions mainly differ in geopotential coefficients from degree 2 to 5. This can be explained by the fact that the nuisance parameters and the gravity field coefficients are highly correlated, particularly at low degrees. We compare these solutions with the official and published ones by means of spectral analysis. It is

  4. An investigation of pulsed high density plasmas

    International Nuclear Information System (INIS)

    Timmermans, C.J.

    1984-01-01

    In this thesis a wall-stabilized argon cascade arc is studied at values of pulsed pressure up to 14 bar and a pulsed current range up to 2200 A with a time duration of about 2 ms. The basic plasma is a CW cascade arc with a 5 mm diameter plasma column and a length of 90 mm, which operates at a 60 A DC current and at one atmosphere filling pressure. The author starts with an extensive summary of the CW arc investigations. After a brief introduction of the basic transport equations the mass equations of the constituent particles are treated using the extended collisional radiative model. The energy balance equations and the momentum balance are discussed. The electron density is determined from measurements of the continuum radiation. The final chapter contains the experimental results on the electron temperatures and electron densities in the pressure and current pulsed plasma. Attention is given to the deviations from local thermodynamic equilibrium values of the ground level densities of the different argon systems. (Auth.)

  5. Investigation of the free electron laser with a guide magnetic field

    International Nuclear Information System (INIS)

    Kwan, T.; Dawson, J.M.

    1979-01-01

    The free electron laser with a static guide magnetic field has been investigated theoretically and by computer simulation using a fully relativistic electromagnetic particle code which has one spatial and three velocity dimensions. By passing a relativistic electron beam through a helical magnetic field, high frequency electromagnetic radiation is generated by its coupling to the negative energy electrostatic beam modes through the helical magnetic field. In the regime of strong guide field where Ω/sub c/e/γ>>k 0 v/sub 0z/, the dispersion relation is obtained by using a fluid model for the electron beam and the growth rates are solved for numerically. Reasonable agreement between the theory and the simulations has been obtained. It was found that the growth rate increases linearly with magnetic ripple strength but decreases with the strength of the guide field. In addition, the growth rates also increase slightly with the beam energy. For a reasonably strong guide field (e.g., Ω/sub c/e=6.0ω/sub p/e), the growth rate can be on the order of 0.1ω/sub p/e and the efficiency of radiation production has been found to be as high as 16%. However, the efficiency decreases with the strength of the guide field. A theory for the saturation level is developed which relates the efficiency to the continued growth of the electromagnetic wave after the onset of trapping by the electrostatic field. It is found that the growth continues for about one bounce time and the observed saturation levels are reasonably well explained

  6. Enhanced Field Emission Studies on Niobium Surfaces Relevant to High Field Superconducting Radio-Frequency Devices

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tong [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2002-09-18

    Enhanced field emission (EFE) presents the main impediment to higher acceleration gradients in superconducting niobium (Nb) radiofrequency cavities for particle accelerators. The strength, number and sources of EFE sites strongly depend on surface preparation and handling. The main objective of this thesis project is to systematically investigate the sources of EFE from Nb, to evaluate the best available surface preparation techniques with respect to resulting field emission, and to establish an optimized process to minimize or eliminate EFE. To achieve these goals, a scanning field emission microscope (SFEM) was designed and built as an extension to an existing commercial scanning electron microscope (SEM). In the SFEM chamber of ultra high vacuum, a sample is moved laterally in a raster pattern under a high voltage anode tip for EFE detection and localization. The sample is then transferred under vacuum to the SEM chamber equipped with an energy-dispersive x-ray spectrometer for individual emitting site characterization. Compared to other systems built for similar purposes, this apparatus has low cost and maintenance, high operational flexibility, considerably bigger scan area, as well as reliable performance. EFE sources from planar Nb have been studied after various surface preparation, including chemical etching and electropolishing, combined with ultrasonic or high-pressure water rinse. Emitters have been identified, analyzed and the preparation process has been examined and improved based on EFE results. As a result, field-emission-free or near field-emission-free surfaces at ~140 MV/m have been consistently achieved with the above techniques. Characterization on the remaining emitters leads to the conclusion that no evidence of intrinsic emitters, i.e., no fundamental electric field limit induced by EFE, has been observed up to ~140 MV/m. Chemically etched and electropolished Nb are compared and no significant difference is observed up to ~140 MV/m. To

  7. Field Investigation of Steamside Oxidation for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Larsen, Ole Hede; Jensen, Søren Aakjær

    2004-01-01

    The steamside oxide formed on two TP347H superheater tubes was compared. The two specimens investigated were exposed in situ in power plants in Denmark, one specimen was coarse-grained and the other was fine-grained. Parts of both the coarse-grained and the fine-grained specimens were turned...... (machined on the inner side) to give a constant metal thickness so more precise wall thickness measurements could be undertaken. Machined and non-machined areas were investigated using light optical microscopy, and scanning electron microscopy with EDS analysis. The oxide on the fine-grained specimen...... was also investigated with grazing incidence X-ray diffraction. Results from coarse-grained and fine-grained specimens (machined and non-machined) show that grain size influenced oxide thickness and morphology. The oxides from non-machined specimens has an outer iron rich oxide and an inner iron chromium...

  8. Field investigation source area ST58 old Quartermaster service station, Eielson Air Force Base, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Liikala, T.L.; Evans, J.C.

    1995-01-01

    Source area ST58 is the site of the old Quartermaster service station at Eielson Air Force Base, Alaska. The source area is one of several Source Evaluation Report sites being investigated by Pacific Northwest Laboratory for the US Air Force as candidates for no further remedial action, interim removal action, or a remedial investigation/feasibility study under a Federal Facilities Agreement. The purpose of this work was to characterize source area ST58 and excavate the most contaminated soils for use in composting treatability studies. A field investigation was conducted to determine the nature and extent of soil contamination. The field investigation entailed a records search; grid node location, surface geophysical, and soil gas surveys; and test pit soil sampling. Soil excavation followed based on the results of the field investigation. The site was backfilled with clean soil. Results from this work indicate close spatial correlation between screening instruments, used during the field investigation and soil excavation, and laboratory analyses. Gasoline was identified as the main subsurface contaminant based on the soil gas surveys and test pit soil sampling. A center of contamination was located near the northcentral portion of the source area, and a center was located in the northwestern comer. The contamination typically occurred near or below a former soil horizon probably as a result of surface spills and leaks from discontinuities and/or breaks in the underground piping. Piping locations were delineated during the surface geophysical surveys and corresponded very well to unscaled drawings of the site. The high subsurface concentrations of gasoline detected in the northwestern comer of the source area probably reflect ground-water contamination and/or possibly floating product.

  9. Analytical and Experimental Investigation on A Dynamic Thermo-Sensitive Electrical Parameter with Maximum dIC/dt during Turn-off for High Power Trench Gate/Field-Stop IGBT Modules

    DEFF Research Database (Denmark)

    Chen, Yuxiang; Luo, Haoze; Li, Wuhua

    2017-01-01

    collector current during turn-off process is developed in terms of the behavior characteristics of the inside storage carriers. Then, the inherent linear relationship between the maximum collector current falling rate dI{C}/dt and junction temperature T {j} is demonstrated and investigated. Fortunately......, benefitting from the presence of the intrinsic parasitic inductance L{rm eE} between the Kelvin and power emitters of IGBT modules, the maximum dI{C}/dt can be easily measured to validate the theoretical analysis. Consequently, the maximum dI{C}/dt during turn-off process is a promising DTSEP for IGBT module...

  10. Field-scale investigation of pulverized coal mill power consumption

    Energy Technology Data Exchange (ETDEWEB)

    Ganguli, R.; Bandopadhyay, S. [University of Alaska Fairbanks, Fairbanks, AK (United States)

    2008-08-15

    Twenty field-scale tests were conducted in a 28 MW pulverized coal power plant in Healy, Alaska, to examine mill power consumption in relation to coal grind size. The intent in this field-scale study was to verify if grind size truly impacted power consumption by a detectable amount. The regression model developed from the data indicates that grind size does impact mill power consumption, with finer grinds consuming significantly more power than coarser grinds. However, other factors such as coal hardness (i.e. the lower the Hardgrove Grindability Index, or the harder the coal, the higher the power consumption) and mill throughput (i.e., the higher the throughput, the higher the power consumption) had to be included before the impact of grind size could be isolated. It was also observed that combining amperage and flow rate into a single parameter, i.e., specific amperage, hurt modeling. Cost analysis based on the regression model indicate a power savings of $19,972 per year if the coal were ground to 50% passing 76 {mu}m rather than the industry standard of 70% passing 76 {mu}m. The study also demonstrated that size reduction constituted a significant portion of the power consumption.

  11. Durability of marine concrete structures - field investigations and modelling

    NARCIS (Netherlands)

    Polder, R.B.; Rooij, M.R. de

    2005-01-01

    This article presents a series of investigations on six concrete structures along the North Sea coast in The Netherlands. They had ages between 18 and 41 years and most of them were made using Blast Furnace Slag cement. Visual inspections showed corrosion damage in only one structure, related to

  12. Durability of marine concrete structures - field investigations and modelling

    NARCIS (Netherlands)

    Polder, R.B.; Rooij, M.R. de

    2006-01-01

    This article presents a series of investigations on six concrete structures along the North Sea coast in The Netherlands. They had ages between 18 and 41 years and most of them were made using Blast Furnace Slag cement. Visual inspections showed corrosion damage in only one structure, related to

  13. Innovative Field Investigations in Limestone using a FACT-FLUTe

    DEFF Research Database (Denmark)

    Mosthaf, Klaus; Barrett Sørensen, Mie; Broholm, Mette Martina

    2015-01-01

    from the Water-FLUTe multilevels (Janniche et al. 2013 and 2013b) at the site. Method and technique The FLUTe Activated Carbon Technique was described e.g. in Janniche et al. (2013). The sorption of chlorinated ethenes on activated carbon was determined in laboratory experiments as described...... in Sørensen et al. (2014) to obtain equilibrium sorption coefficients (Kd) for individual and mixed chlorinated ethenes on activated carbon from aqueous solution. As the uptake on FACT in limestone aquifers will depend on transport (advection and/or diffusion and retardation by sorption) in the limestone...... matrix and fractures as well as on the sorption to activated carbon, a modeling tool was developed (Mosthaf et al. 2014) which allows for the interpretation of field data and the analysis of the influence of various aquifer parameters. The model provides a link between sorbed concentrations on the FACT...

  14. Results of investigation at the Ahuachapan Geothermal Field, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.B. (HydroGeophysics, Tucson, AZ (United States))

    1990-04-01

    The Ahuachapan Geothermal Field (AGF) is a 95 megawatt geothemal-sourced power-plant operated by the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) of El Salvador. During the past decade, as part of an effort to increase in situ thermal reserves in order to realize the full generation capacity of the AGF, extensive surface geophysical coverage has been obtained over the AGF and the prospective Chipilapa area to the east. The geophysical surveys were performed to determine physical property characteristics of the known reservoir and then to search for similar characteristics in the Chipilapa area. A secondary objective was to evaluate the surface recharge area in the highlands to the south of the AGF. The principal surface electrical geophysical methods used during this period were DC resistivity and magnetotellurics. Three available data sets have been reinterpreted using drillhole control to help form geophysical models of the area. The geophysical models are compared with the geologic interpretations.

  15. COMPARATIVE FIELD EXPERIMENTAL INVESTIGATIONS OF DIFFERENT FLAT PLATE SOLAR COLLECTORS

    Directory of Open Access Journals (Sweden)

    Guangming Chen

    2015-12-01

    Full Text Available Full-scale traditional metal solar collectors and solar collector specimens fabricated from polymeric materials were investigated in the present study. A polymeric collector is 67.8% lighter than a traditional metal solar collector, and a metal solar collector with transparent plastic covering is 40.3% lighter than a traditional metal solar collector. Honeycomb multichannel plates made from polycarbonate were chosen to create a polymeric solar collector. A test rig for the natural circulation of the working fluid in a solar collector was built for a comparative experimental investigation of various solar collectors operating at ambient conditions. It was shown experimentally that the efficiency of a polymeric collector is 8–15% lower than the efficiency of a traditional collector.

  16. Numerical investigation of space charge electric field for a sheet ...

    Indian Academy of Sciences (India)

    One of the problems in scaling high power vacuum and plasma microwave sources to higher frequencies is the need to transport beams with higher space charge density, since the radio frequency circuit transverse dimensions tend to decrease with wavelength. The use of sheet electron beams can alleviate this difficulty ...

  17. Radiofrequency solutions in clinical high field magnetic resonance

    NARCIS (Netherlands)

    Andreychenko, A.

    2013-01-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) benefit from the sensitivity gain at high field (≥7T). However, high field brings also certain challenges associated with growing frequency and spectral dispersion. Frequency growth results in degraded performance of large volume radiofrequency

  18. Final report: High current capacity high temperature superconducting film based tape for high field magnets

    International Nuclear Information System (INIS)

    Ying Xin

    2000-01-01

    The primary goal of the program was to establish the process parameters for the continuous deposition of high quality, superconducting YBCO films on one meter lengths of buffered RABiTS tape using MOCVD and to characterize the potential utility of the resulting tapes in high field magnet applications

  19. Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field

    International Nuclear Information System (INIS)

    Abraimov, D; Francis, A; Jaroszynski, J; McCallister, J; Polyanskii, A; Santos, M; Viouchkov, Y L; Ballarino, A; Bottura, L; Rossi, L; Barth, C; Senatore, C; Dietrich, R; Rutt, A; Schlenga, K; Usoskin, A; Majkic, G S; Selvamanickam, V

    2015-01-01

    A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa 2 Cu 3 O x−δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed. (paper)

  20. Final Report: Experimental Investigation of Nonlinear Plasma Wake-Fields

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, J.

    1997-10-31

    We discuss the exploration of the newly proposed blowout regime of the plasma wakefield accelerator and advanced photoinjector technology for linear collider applications. The plasma wakefield experiment at ANL produced several ground-breaking results in the physics of the blowout regime. The photoinjector R and D effort produced breakthroughs in theoretical, computational, and experimental methods in high brightness beam physics. Results have been published.

  1. Field emission behavior of carbon nanotube field emitters after high temperature thermal annealing

    Directory of Open Access Journals (Sweden)

    Yuning Sun

    2014-07-01

    Full Text Available The carbon nanotube (CNT field emitters have been fabricated by attaching a CNT film on a graphite rod using graphite adhesive material. The CNT field emitters showed much improved field emission properties due to increasing crystallinity and decreasing defects in CNTs after the high temperature thermal annealing at 900 °C in vacuum ambient. The CNT field emitters showed the low turn-on electric field of 1.15 V/μm, the low threshold electric field of 1.62 V/μm, and the high emission current of 5.9 mA which corresponds to a current density of 8.5 A/cm2. In addition, the CNT field emitters indicated the enhanced field emission properties due to the multi-stage effect when the length of the graphite rod increases. The CNT field emitter showed good field emission stability after the high temperature thermal annealing. The CNT field emitter revealed a focused electron beam spot without any focusing electrodes and also showed good field emission repeatability.

  2. High magnetic field properties of Fe-pnictide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kurth, Fritz

    2015-11-20

    The recent discovery of high-temperature superconductivity in Fe-based materials triggered worldwide efforts to investigate their fundamental properties. Despite a lot of similarities to cuprates and MgB{sub 2}, important differences like near isotropic behaviour in contrast to cuprates and the peculiar pairing symmetry of the order parameter (OP) have been reported. The OP symmetry of Fe-based superconductors (FBS) was theoretically predicted to be of so-called s± state prior to various experimental works. Still, most of the experimental results favour the s± scenario; however, definitive evidence has not yet been reported. Although no clear understanding of the superconducting mechanisms yet exists, potential applications such as high-field magnets and Josephson devices have been explored. Indeed, a lot of reports about FBS tapes, wires, and even SQUIDs have been published to this date. In this thesis, the feasibility of high-field magnet applications of FBS is addressed by studying their transport properties, involving doped BaFe{sub 2}As{sub 2} (Ba-122) and LnFeAs(O,F) [Ln=Sm and Nd]. Particularly, it is important to study physical properties in a sample form (i.e. thin films) that is close to the conditions found in applications. However, the realisation of epitaxial FBS thin films is not an easy undertaking. Recent success in growing epitaxial FBS thin films opens a new avenue to delve into transport critical current measurements. The information obtained through this research will be useful for exploring high-field magnet applications. This thesis consists of 7 chapters: Chapter 1 describes the motivation of this study, the basic background of superconductivity, and a brief summary of the thin film growth of FBS. Chapter 2 describes experimental methods employed in this study. Chapter 3 reports on the fabrication of Co-doped Ba-122 thin films on various substrates. Particular emphasis lies on the discovery of fluoride substrates to be beneficial for

  3. Summary of Geophysical Field Investigations to Constrain the Geologic Structure and Hydrologic Characteristics of Fortymile Wash Essential for Assessing the Performance of the Proposed High-Level Nuclear Waste Repository at Yucca Mountain, Nevada

    Science.gov (United States)

    Farrell, D. A.; La Femina, P.; Winterle, J.; Hill, M.; Sims, D.; Smith, M.; Green, R.; Illman, W.; Sandberg, S.; Rogers, N.

    2001-12-01

    The U.S. Department of Energy (DOE) is currently evaluating Yucca Mountain, located in southwestern Nevada, as a possible geologic high-level nuclear waste repository with a performance period of 10,000 years. Groundwater flow and possible radionuclide transport from Yucca Mountain within the saturated zone will be influenced by the geologic structure and the hydrogeologic characteristics of the subsurface in the vicinity of the site. An understanding of these characteristics is essential to evaluating the performance of the repository. South of Yucca Mountain, along the anticipated radionuclide transport pathway, uncertainties in structural geology, hydrogeologic models, and supporting data (for example, the location of the watertable transition from tuff to valley-fill, and the architecture of the basin) impact site performance assessment calculations. Some of these uncertainties will be reduced by the point information provided by the well drilling program currently being carried out by Nye County, Nevada. However, geologic and hydrologic uncertainties remain within inter-well regions which extend over several tens of square kilometers. In recognition of the uncertainties inherent in analyses based upon relatively sparse point data available for Fortymile Wash, the Center for Nuclear Waste Regulatory Analyses and the Nuclear Regulatory Commission have developed a surface geophysics program that targets the inter-well regions utilizing gravity, magnetic, electrical resistivity, and electromagnetic measurements to support confirmatory analyses and performance assessment calculations. This presentation describes various aspects of these surveys and their results. In particular, the presentation presents new models for the structure of the Fortymile Wash (including an improved mapping of the tuff valley-fill interface) based on the integrated geophysical approach and provides an independent basis for the watertable configuration over the region. By combining the

  4. Light-induced electric field generated by photovoltaic substrates investigated through liquid crystal reorientation

    Science.gov (United States)

    Lucchetti, L.; Kushnir, K.; Reshetnyak, V.; Ciciulla, F.; Zaltron, A.; Sada, C.; Simoni, F.

    2017-11-01

    Liquid crystal reorientation is exploited to analyze the electric field generated by light irradiation in iron-doped lithium niobate crystals. The evaluation of the strength of this light-induced field is based on the measurement of the phase shift induced in a probe light beam by a liquid crystal cell built with two z-cut iron-doped lithium niobate crystals as substrates. Then, the field profile has been determined starting from a Gaussian-like surface charge density following the model described in the text. The director profile corresponding to the modelled electric field is in good agreement with the director reorientation evaluated experimentally by means of the light-induced phase shift. This investigation gives a new approach to study the effects based on the photovoltaic response of lithium niobate crystals. Moreover, the characterization of the electric field optically generated inside the LC layer is highly desirable in view of the realization of new all-optical devices to be integrated in optofluidic platforms.

  5. Results of investigations at the Zunil geothermal field, Guatemala: Well logging and brine geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Adams, A.; Dennis, B.; Van Eeckhout, E.; Goff, F.; Lawton, R.; Trujillo, P.E.; Counce, D.; Archuleta, J. (Los Alamos National Lab., NM (USA)); Medina, V. (Instituto Nacional de Electrificacion, Guatemala City (Guatemala). Unidad de Desarollo Geotermico)

    1991-07-01

    The well logging team from Los Alamos and its counterpart from Central America were tasked to investigate the condition of four producing geothermal wells in the Zunil Geothermal Field. The information obtained would be used to help evaluate the Zunil geothermal reservoir in terms of possible additional drilling and future power plant design. The field activities focused on downhole measurements in four production wells (ZCQ-3, ZCQ-4, ZCQ-5, and ZCQ-6). The teams took measurements of the wells in both static (shut-in) and flowing conditions, using the high-temperature well logging tools developed at Los Alamos National Laboratory. Two well logging missions were conducted in the Zunil field. In October 1988 measurements were made in well ZCQ-3, ZCQ-5, and ZCQ-6. In December 1989 the second field operation logged ZCQ-4 and repeated logs in ZCQ-3. Both field operations included not only well logging but the collecting of numerous fluid samples from both thermal and nonthermal waters. 18 refs., 22 figs., 7 tabs.

  6. Near-field issues - Investigation of gas generation in situ

    International Nuclear Information System (INIS)

    Szanto, Zs.; Svingor, E.; Palcsu, L.; Mihaly, M.; Futo, I.

    2001-01-01

    The Puespoekszilagy Radioactive Waste Treatment and Disposal Facility is a typical near-surface engineered repository consisting of concrete vaults and wells for the disposal of spent sources. It has received waste from the Paks Nuclear Power Plant, from various laboratories and medical institutions, and, in particular, has been the site for the disposal of a number of spent sources. The safety of the repository has not been the subject of any comprehensive assessment, and does not have a permanent license. In 15th of March an A-type concrete vault was opened and the work was focused on issues that are critical for safety: characterisation of the behavior of the wastes, the degradation of the packaging, the chemical environment in the vaults, the chemical behavior of relevant radionuclides and the processes determining any migration of any radionuclide from the engineered system. Generic data can be used on rates of steel corrosion but an in situ measurement of head space gas composition and a detailed laboratory analysis give more relevant data. In addition to the radionuclide inventory a general estimate of the type of materials present (metals, halogenated and non-halogenated plastics and rubbers, cellulosic, building materials, organic, biological, flammable liquids, materials that may give rise to the generation of gas, etc.) was made and from these results in respect of radioactive gases, it seemed that the gases to be addressed should be 14 C-labelled methane and carbon dioxide, 3 H-labelled hydrogen, water vapor and methane, and 222 Rn. Before removing the protective lids sampling of the headspace gas of the vaults was performed by a special gas outlet system through the concrete cap. One of the cells (Code: A5) contained unconditioned radioactive waste disposed in polythene bags into the vault, without any backfilling. The other cell (Code: A6) was backfilled with cement, so there was a small gas field between the top of the surface of the backfill and the

  7. Investigation of parts and elements of technical reports in nuclear field in Japan

    International Nuclear Information System (INIS)

    Naramoto, Miyoko; Narui, Shigeko

    1985-01-01

    Presentation of parts and elements necessary for editing and publishing reports in accordance with SIST-09-1984 (Presentation of Scientific and Technical Reports) was investigated for 65 codes of technical reports in the nuclear field in Japan. English presentation of important elements was also investigated additionally. The investigation shows high presentation fractions (80 -- 100 %) for main bibliographic elements, and medium (66 %) and extremely low (3 %) for abntract and key word, respectively. (The bibliographic elements are described in various parts such as front cover, title page and front matter) and (the subject elements appear mainly in front matter). The title, author's name in Roman character, affiliation, publisher and abstract are described in English with fractions of 80 %, 66 %, 68 % and 62 %, respectively. It is hoped for more publishers and editors of technical reports to accept the standard SIST-09 for efficient processing of secondary information. (author)

  8. Analysis of a high brightness photo electron beam with self field and wake field effects

    International Nuclear Information System (INIS)

    Parsa, Z.

    1991-01-01

    High brightness sources are the basic ingredients in the new accelerator developments such as Free-Electron Laser experiments. The effects of the interactions between the highly charged particles and the fields in the accelerating structure, e.g. R.F., Space charge and Wake fields can be detrimental to the beam and the experiments. We present and discuss the formulation used, some simulation and results for the Brookhaven National Laboratory high brightness beam that illustrates effects of the accelerating field, space charge forces (e.g. due to self field of the bunch), and the wake field (e.g. arising from the interaction of the cavity surface and the self field of the bunch)

  9. Bit selection using field drilling data and mathematical investigation

    Science.gov (United States)

    Momeni, M. S.; Ridha, S.; Hosseini, S. J.; Meyghani, B.; Emamian, S. S.

    2018-03-01

    A drilling process will not be complete without the usage of a drill bit. Therefore, bit selection is considered to be an important task in drilling optimization process. To select a bit is considered as an important issue in planning and designing a well. This is simply because the cost of drilling bit in total cost is quite high. Thus, to perform this task, aback propagation ANN Model is developed. This is done by training the model using several wells and it is done by the usage of drilling bit records from offset wells. In this project, two models are developed by the usage of the ANN. One is to find predicted IADC bit code and one is to find Predicted ROP. Stage 1 was to find the IADC bit code by using all the given filed data. The output is the Targeted IADC bit code. Stage 2 was to find the Predicted ROP values using the gained IADC bit code in Stage 1. Next is Stage 3 where the Predicted ROP value is used back again in the data set to gain Predicted IADC bit code value. The output is the Predicted IADC bit code. Thus, at the end, there are two models that give the Predicted ROP values and Predicted IADC bit code values.

  10. Developments in materials for high-field magnets

    Energy Technology Data Exchange (ETDEWEB)

    Sims, J.R.; Hill, M.A. [Los Alamos National Lab., NM (United States); Walsh, R.P. [National Inst. of Standards and Technology (MSEL), Boulder, CO (United States). Materials Reliability Div.

    1993-10-01

    Results of the National High Magnetic Field Laboratory`s program of characterization of materials and fabrication techniques used in the construction of high-field pulsed magnets are reported. High-field pulsed magnets require conductors with high mechanical strength (750 MPa or greater YS at 77K) and high electrical conductivity (70% IACS or greater at RT). Electrical insulation and resin systems for vacuum impregnation with high compressive strength (500 MPa at 77K) and moderate thermal conductivity (1kW/mK at 77K) are also required. Developments and future plans for the characterization of new magnet material systems are discussed. Testing result are reported: Mechanical and fatigue testing, electrical conductivity testing and thermal expansion measurements of high strength, high conductivity conductors at cryogenic and room temperature, mechanical testing of a coil support material at cryogenic and room temperature, thermal expansion and thermal conductivity tests of an electrical insulating system at cryogenic temperatures.

  11. Superconductivity in an Organic Insulator at Very High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Balicas, L.; Brooks, J. S.; Storr, K.; Uji, S.; Tokumoto, M.; Tanaka, H.; Kobayashi, H.; Kobayashi, A.; Barzykin, V.; Gor' kov, L. P.

    2001-08-06

    We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor {lambda}-(BETS){sub 2}FeCl{sub 4} . Below 4K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41T and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe{sup 3+} ions. We further argue that the Fe{sup 3+} moments are essential to stabilize the resulting singlet, two-dimensional superconducting state.

  12. Superconductivity in an organic insulator at very high magnetic fields.

    Science.gov (United States)

    Balicas, L; Brooks, J S; Storr, K; Uji, S; Tokumoto, M; Tanaka, H; Kobayashi, H; Kobayashi, A; Barzykin, V; Gor'kov, L P

    2001-08-06

    We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor lambda-(BETS)2FeCl4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe3+ ions. We further argue that the Fe3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state.

  13. HIFI - a dedicated HIgh-FIeld diffraction and spectroscopy instrument

    International Nuclear Information System (INIS)

    Steffens, P.; Enderle, M.; Boehm, M.; Roux, S.

    2011-01-01

    The outstanding scientific impact of single-crystal neutron diffraction and spectroscopy in steady state vertical magnetic fields up to 15 T (17 T without dilution fringe) is reflected in numerous high-profile publications. Magnetic fields 30 T - 35 T in vertical geometry allow to address enigmatic questions without equivalence at lower fields. The constraints implied by such magnetic fields demand a specially designed dedicated instrument. Since the vertical field geometry is crucial for single-crystal diffraction as well as spectroscopy, the solid angle of scattered neutrons is restricted, and a high-flux reactor is best suited to host a corresponding instrument. We propose a world-wide unique versatile instrument for diffraction and spectroscopy in vertical steady fields of 30 T. (authors)

  14. High magnetic field μSR instrument scientific case

    International Nuclear Information System (INIS)

    Amato, A.

    2005-10-01

    In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the μSR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI μSR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during μSR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for μSR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field -4 Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

  15. High magnetic field {mu}SR instrument scientific case

    Energy Technology Data Exchange (ETDEWEB)

    Amato, A

    2005-10-15

    In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the {mu}SR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI {mu}SR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during {mu}SR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for {mu}SR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field < 10{sup -4} Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

  16. Impact of high magnetic fields on fusion systems

    International Nuclear Information System (INIS)

    Cohn, D.R.

    1989-01-01

    High field concepts can provide significant advantages for the size and performance of tokamak fusion reactors. These devices would make use of advanced superconductors and structural materials. Use of high plasma aspect ratios, super high field operation, and strong ohmic heating are promising new directions. The tokamak device has been demonstrated to be the most effective magnetic confinement machine for obtaining the burning plasma conditions required for a fusion reactor. Analysis of present experimental results together with basic theoretical considerations indicates that high magnetic fields can have a large beneficial impact on reactor performance and cost. At the same time superconducting magnet technology has been steadily advancing. Concepts that maximize the beneficial impacts of high fields and make use of advanced superconducting magnet technology could thus have a profound impact on the development of fusion systems. In this paper the authors discuss this approach and describe some promising directions

  17. Ground-based complex for detection and investigation of fast optical transients in wide field

    Science.gov (United States)

    Molinari, Emilio; Beskin, Grigory; Bondar, Sergey; Karpov, Sergey; Plokhotnichenko, Vladimir; de-Bur, Vjacheslav; Greco, Guiseppe; Bartolini, Corrado; Guarnieri, Adriano; Piccioni, Adalberto

    2008-07-01

    To study short stochastic optical flares of different objects (GRBs, SNs, etc) of unknown localizations as well as NEOs it is necessary to monitor large regions of sky with high time resolution. We developed a system which consists of wide-field camera (FOW is 400-600 sq.deg.) using TV-CCD with time resolution of 0.13 s to record and classify optical transients, and a fast robotic telescope aimed to perform their spectroscopic and photometric investigation just after detection. Such two telescope complex TORTOREM combining wide-field camera TORTORA and robotic telescope REM operated from May 2006 at La Silla ESO observatory. Some results of its operation, including first fast time resolution study of optical transient accompanying GRB and discovery of its fine time structure, are presented. Prospects for improving the complex efficiency are given.

  18. Improving Magnet Designs With High and Low Field Regions

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2011-01-01

    A general scheme for increasing the difference in magnetic flux density between a high and a low magnetic field region by removing unnecessary magnet material is presented. This is important in, e.g., magnetic refrigeration where magnet arrays have to deliver high field regions in close proximity...... to low field regions. Also, a general way to replace magnet material with a high permeability soft magnetic material where appropriate is discussed. As an example, these schemes are applied to a two dimensional concentric Halbach cylinder design resulting in a reduction of the amount of magnet material...

  19. Limited field investigation report for the 100-DR-1 Operable Unit

    International Nuclear Information System (INIS)

    1994-06-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-DR-1 Source Operable Unite LFI and the associated qualitative risk assessment (QRA), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. The 100-DR-1 Operable Unit is one of four operable units associated with the 100 D/DR Area at the Hanford Site. The 100-DR-1 Operable Unit encompasses approximately 1.5 km 2 (0.59 mi 2 ) and is located immediately adjacent to the Columbia River shoreline. In general, it contains waste facilities associated with the original plant facilities constructed to support D Reactor facilities, as well as cooling water retention basin systems for both D and DR Reactors. The 100-DR-1 LFI began the investigative phase of the remedial investigation for a select number of high-priority sites. The LFI was performed to provide additional data needed to support selection, design and implementation of IRM, if needed. The LFI included data compilation, nonintrusive investigations, intrusive investigations, summarization of 100 Area aggregate studies, and data evaluation

  20. Limited field investigation report for the 100-DR-1 Operable Unit

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-DR-1 Source Operable Unite LFI and the associated qualitative risk assessment (QRA), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. The 100-DR-1 Operable Unit is one of four operable units associated with the 100 D/DR Area at the Hanford Site. The 100-DR-1 Operable Unit encompasses approximately 1.5 km{sup 2} (0.59 mi{sup 2}) and is located immediately adjacent to the Columbia River shoreline. In general, it contains waste facilities associated with the original plant facilities constructed to support D Reactor facilities, as well as cooling water retention basin systems for both D and DR Reactors. The 100-DR-1 LFI began the investigative phase of the remedial investigation for a select number of high-priority sites. The LFI was performed to provide additional data needed to support selection, design and implementation of IRM, if needed. The LFI included data compilation, nonintrusive investigations, intrusive investigations, summarization of 100 Area aggregate studies, and data evaluation.

  1. Microbial diversity of a high salinity oil field

    International Nuclear Information System (INIS)

    Neria, I.; Gales, G.; Alazard, D.; Ollivier, B.; Borgomano, J.; Joulian, C.

    2009-01-01

    This work is a preliminary study to investigate the microbial diversity of an onshore oil field. It aim to compare results obtained from molecular methods, physicochemical analyses and cultivation. A core of 1150 m depth sediments ( in situ T=45 degree centigrade) was collected and immediately frozen with liquid nitrogen prior to further investigation. Macroscopic and Scanning Electron Microscopy analyses were performed. (Author)

  2. High pressure apparatus transport properties study in high magnetic field

    Czech Academy of Sciences Publication Activity Database

    Honda, F.; Sechovský, V.; Mikulina, O.; Kamarád, Jiří; Alsmadi, A. M.; Nakotte, H.; Lacerda, A. H.

    2002-01-01

    Roč. 16, 20, 21 & 22 (2002), s. 3330-3333 ISSN 0217-9792 R&D Projects: GA ČR GP202/01/D045; GA ČR GA202/00/1217; GA MŠk ME 165 Grant - others:NSF(XX) DMR-0094241 Institutional research plan: CEZ:AV0Z1010914 Keywords : high-pressure apparatus Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.604, year: 2002

  3. High magnetic fields in couplers of x-band acceleratingstructures

    CERN Document Server

    Dolgashev, V A

    2003-01-01

    Recent high power tests of x-band accelerating structures at SLAC have shown that Coupler models were matched with an automated procedure that uses the commercial To reduce the high magnetic fields new couplers were designed. These couplers and typical results for couplers with sharp and rounded irises are discussed in code HFSS. This matching procedure is based on calculation of reflection from have 3 mm radius waveguide-to-coupler-cell iris and maximum magnetic field below is consistent with a model of pulsed heating due to high magnetic fields. The magnetic fields, 3D electrodynamics models of the couplers were built and matched. matching, the magnetic and electric fields in the couplers were calculated for typical observed damage is located in the region of high magnetic fields. To calculate these on sharp (approx 80 micron radius) edges of the waveguide-to-coupler-cell irises. For operation parameters. Highest magnetic fields on the order of 1 MA/m were found some input couplers, electric fields on these...

  4. High-field magnetization of UCuGe single crystal

    Czech Academy of Sciences Publication Activity Database

    Andreev, Alexander V.; Mushnikov, N. V.; Gozo, T.; Honda, F.; Sechovský, V.; Prokeš, K.

    346-347, - (2004), s. 132-136 ISSN 0921-4526 R&D Projects: GA ČR GA202/02/0739 Institutional research plan: CEZ:AV0Z1010914 Keywords : uranium intermetallics * UCuGe * high fields * magnetic anisotropy * field-induced phase transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.679, year: 2004

  5. Field manual for identifying and preserving high-water mark data

    Science.gov (United States)

    Feaster, Toby D.; Koenig, Todd A.

    2017-09-26

    This field manual provides general guidance for identifying and collecting high-water marks and is meant to be used by field personnel as a quick reference. The field manual describes purposes for collecting and documenting high-water marks along with the most common types of high-water marks. The manual provides a list of suggested field equipment, describes rules of thumb and best practices for finding high-water marks, and describes the importance of evaluating each high-water mark and assigning a numeric uncertainty value as part of the flagging process. The manual also includes an appendix of photographs of a variety of high-water marks obtained from various U.S. Geological Survey field investigations along with general comments about the logic for the assigned uncertainty values.

  6. Experimental investigation of the velocity field in buoyant diffusion flames using PIV and TPIV algorithm

    Science.gov (United States)

    L. Sun; X. Zhou; S.M. Mahalingam; D.R. Weise

    2005-01-01

    We investigated a simultaneous temporally and spatially resolved 2-D velocity field above a burning circular pan of alcohol using particle image velocimetry (PIV). The results obtained from PIV were used to assess a thermal particle image velocimetry (TPIV) algorithm previously developed to approximate the velocity field using the temperature field, simultaneously...

  7. Experimental investigation of magnetic-field topology via a perturbation method in the PFRC-2 device

    Science.gov (United States)

    Matteucci, Jackson; Cohen, Samuel

    2015-11-01

    The fundamental question about FRC experiments is whether an FRC has actually formed; specifically, does there exist a magnetized, high-beta, plasma configuration with both no toroidal field and a simply connected configuration-space separatrix? We have investigated the latter part of this question, the existence of a separatrix, in the RMF_o-driven PFRC-2 device. The method involved applying an externally generated periodic RF power perturbation to open-field-line plasma at one (remote) axial end of the device while simultaneously searching for evidence of this perturbation near the presumptive FRC. Measurements of the floating potential and ion saturation current were taken at the axial center of the device using a cylindrical Langmuir probe (r = 0.025 cm). When applying no RMF_o, measurements of the floating potential and the ion saturation current showed evidence of the frequency signature of perturbation throughout the entire radial profile of the device, indicating open field lines throughout the device. However, under certain conditions when operating the RMF_o, we found no evidence of the perturbation within a certain radius, but instead see the perturbations only beyond this particular radius, indicating a separatrix inside which the magnetic field lines are closed. This work supported by DOE contract DE-AC02-09CH11466.

  8. Numerical investigation of the contraction of neutral-charged diblock copolymer brushes in electric fields

    International Nuclear Information System (INIS)

    Chen, Yuwei; Li, Haiming; Zhu, Yuejin; Tong, Chaohui

    2016-01-01

    Using self-consistent field theory (SCFT), the contraction of neutral-charged A-B diblock copolymer brushes in electric fields generated by opposite surface charges on two parallel electrodes has been numerically investigated. The diblock copolymer chains were grafted with the free end of the neutral block to one electrode and immersed in a salt-free solution sandwiched between the two electrodes. The numerical results reveal that the charged monomers, A-B joint segment and the tail exhibit bimodal distributions under external electric fields, which are absent for homopolymer polyelectrolyte brushes. The dependences of the relative populations and peak positions of the two modes on various parameters such as block ratio, grafting density, chain length and strength of the applied electric field were systematically examined and the underlining mechanisms were elucidated. It was found in this study that, if the total amount of surface charges on the grafting electrode is no more than that of the counter-ions in the system, overall charge neutrality is generally maintained inside the brushes when including the contribution of surface charges on the grafting electrode. In such a case, the counter-ions expelled from the brushes are highly enriched in the immediate vicinity of the second electrode and an approximate charge balance between these expelled counter-ions and the opposite surface charges on the second electrode is achieved. (paper)

  9. Investigating Non-Equilibrium Fluctuations of Nanocolloids in a Magnetic Field Using Direct Imaging Methods

    Science.gov (United States)

    Rice, Ashley; Oprisan, Ana; Oprisan, Sorinel; Rice-Oprisan College of Charleston Team

    Nanoparticles of iron oxide have a high surface area and can be controlled by an external magnetic field. Since they have a fast response to the applied magnetic field, these systems have been used for numerous in vivo applications, such as MRI contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery, and cell separation. We performed three direct imaging experiments in order to investigate the concentration-driven fluctuations using magnetic nanoparticles in the absence and in the presence of magnetic field. Our direct imaging experimental setup involved a glass cell filled with magnetic nanocolloidal suspension and water with the concentration gradient oriented against the gravitational field and a superluminescent diode (SLD) as the light source. Nonequilibrium concentration-driven fluctuations were recorded using a direct imaging technique. We used a dynamic structure factor algorithm for image processing in order to compute the structure factor and to find the power law exponents. We saw evidence of large concentration fluctuations and permanent magnetism. Further research will use the correlation time to approximate the diffusion coefficient for the free diffusion experiment. Funded by College of Charleston Department of Undergraduate Research and Creative Activities SURF grant.

  10. Lumbar Modic Changes - A Comparison Between Findings at Low-and High-field MRI

    DEFF Research Database (Denmark)

    Bendix, Tom; Sorensen, Joan S; Henriksson, Gustaf A C

    2012-01-01

    Study Design. A cross-sectional observational study.Objective. To investigate if there is a difference in findings of lumbar Modic changes in low-field (0.3 Tesla) magnetic resonance imaging (MRI) as compared to high field (1.5 Tesla).Summary of Background Data. It is a challenge to give patients...

  11. Mitigated-force carriage for high magnetic field environments

    Science.gov (United States)

    Ludtka, Gerard M.; Ludtka, Gail M.; Wilgen, John B.; Murphy, Bart L.

    2015-05-19

    A carriage for high magnetic field environments includes a plurality of work-piece separators disposed in an operable relationship with a work-piece processing magnet having a magnetic field strength of at least 1 Tesla for supporting and separating a plurality of work-pieces by a preselected, essentially equal spacing, so that, as a first work-piece is inserted into the magnetic field, a second work-piece is simultaneously withdrawn from the magnetic field, so that an attractive magnetic force imparted on the first work-piece offsets a resistive magnetic force imparted on the second work-piece.

  12. Overlay control methodology comparison: field-by-field and high-order methods

    Science.gov (United States)

    Huang, Chun-Yen; Chiu, Chui-Fu; Wu, Wen-Bin; Shih, Chiang-Lin; Huang, Chin-Chou Kevin; Huang, Healthy; Choi, DongSub; Pierson, Bill; Robinson, John C.

    2012-03-01

    Overlay control in advanced integrated circuit (IC) manufacturing is becoming one of the leading lithographic challenges in the 3x and 2x nm process nodes. Production overlay control can no longer meet the stringent emerging requirements based on linear composite wafer and field models with sampling of 10 to 20 fields and 4 to 5 sites per field, which was the industry standard for many years. Methods that have emerged include overlay metrology in many or all fields, including the high order field model method called high order control (HOC), and field by field control (FxFc) methods also called correction per exposure. The HOC and FxFc methods were initially introduced as relatively infrequent scanner qualification activities meant to supplement linear production schemes. More recently, however, it is clear that production control is also requiring intense sampling, similar high order and FxFc methods. The added control benefits of high order and FxFc overlay methods need to be balanced with the increased metrology requirements, however, without putting material at risk. Of critical importance is the proper control of edge fields, which requires intensive sampling in order to minimize signatures. In this study we compare various methods of overlay control including the performance levels that can be achieved.

  13. Remedial investigation sampling and analysis plan for J-Field, Aberdeen Proving Ground, Maryland. Volume 1: Field Sampling Plan

    Energy Technology Data Exchange (ETDEWEB)

    Benioff, P.; Biang, R.; Dolak, D.; Dunn, C.; Martino, L.; Patton, T.; Wang, Y.; Yuen, C.

    1995-03-01

    The Environmental Management Division (EMD) of Aberdeen Proving Ground (APG), Maryland, is conducting a remedial investigation and feasibility study (RI/FS) of the J-Field area at APG pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended. J-Field is within the Edgewood Area of APG in Harford County, Maryland (Figure 1. 1). Since World War II activities in the Edgewood Area have included the development, manufacture, testing, and destruction of chemical agents and munitions. These materials were destroyed at J-Field by open burning and open detonation (OB/OD). Considerable archival information about J-Field exists as a result of efforts by APG staff to characterize the hazards associated with the site. Contamination of J-Field was first detected during an environmental survey of the Edgewood Area conducted in 1977 and 1978 by the US Army Toxic and Hazardous Materials Agency (USATHAMA) (predecessor to the US Army Environmental Center [AEC]). As part of a subsequent USATHAMA -environmental survey, 11 wells were installed and sampled at J-Field. Contamination at J-Field was also detected during a munitions disposal survey conducted by Princeton Aqua Science in 1983. The Princeton Aqua Science investigation involved the installation and sampling of nine wells and the collection and analysis of surficial and deep composite soil samples. In 1986, a Resource Conservation and Recovery Act (RCRA) permit (MD3-21-002-1355) requiring a basewide RCRA Facility Assessment (RFA) and a hydrogeologic assessment of J-Field was issued by the US Environmental Protection Agency (EPA). In 1987, the US Geological Survey (USGS) began a two-phased hydrogeologic assessment in data were collected to model, groundwater flow at J-Field. Soil gas investigations were conducted, several well clusters were installed, a groundwater flow model was developed, and groundwater and surface water monitoring programs were established that continue today.

  14. Field emission from the surface of highly ordered pyrolytic graphite

    Energy Technology Data Exchange (ETDEWEB)

    Knápek, Alexandr, E-mail: knapek@isibrno.cz [Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno (Czech Republic); Sobola, Dinara; Tománek, Pavel [Department of Physics, FEEC, Brno University of Technology, Technická 8, Brno (Czech Republic); Pokorná, Zuzana; Urbánek, Michal [Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno (Czech Republic)

    2017-02-15

    Highlights: • HOPG shreds were created and analyzed in the UHV conditions. • Current-voltage measurements have been done to confirm electron tunneling, based on the Fowler-Nordheim theory. • Surface was characterized by other surface evaluation methods, in particular by: SNOM, SEM and AFM. - Abstract: This paper deals with the electrical characterization of highly ordered pyrolytic graphite (HOPG) surface based on field emission of electrons. The effect of field emission occurs only at disrupted surface, i.e. surface containing ripped and warped shreds of the uppermost layers of graphite. These deformations provide the necessary field gradients which are required for measuring tunneling current caused by field electron emission. Results of the field emission measurements are correlated with other surface characterization methods such as scanning near-field optical microscopy (SNOM) or atomic force microscopy.

  15. High-field spin dynamics of antiferromagnetic quantum spin chains

    DEFF Research Database (Denmark)

    Enderle, M.; Regnault, L.P.; Broholm, C.

    2000-01-01

    present recent work on the high-field spin dynamics of the S = I antiferromagnetic Heisenberg chains NENP (Haldane ground state) and CsNiCl3 (quasi-1D HAF close to the quantum critical point), the uniform S = 1/2 chain CTS, and the spin-Peierls system CuGeO3. (C) 2000 Elsevier Science B,V. All rights......The characteristic internal order of macroscopic quantum ground states in one-dimensional spin systems is usually not directly accessible, but reflected in the spin dynamics and the field dependence of the magnetic excitations. In high magnetic fields quantum phase transitions are expected. We...

  16. Proceedings of the physical phenomena at high magnetic fields - II

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, Z.; Gor`kov, L.; Meltzer, D.; Schrieffer, R. [eds.

    1996-12-31

    Physical Phenomena at High Magnetic Fields-II was the second conference sponsored by the National High Magnetic Field Laboratory in Tallahassee, FL. The success of the first conference encouraged the Laboratory to once again bring together experts in scientific research areas where high magnetic fields play an important role, to critically assess the current status of research in these areas, and discuss promising new directions in science, as well as applications which are at the forefront of these fields. For the Laboratory, this conference has some additional significance. The Laboratory had just completed its construction stage and full scale scientific efforts were already underway. The Laboratory especially benefited from the invited lectures, original presentations, and open discussions of the conference participants. The Laboratory intends to continue this tradition and host the conference every three years. Separate papers from this proceedings were indexed to the energy database.

  17. Magnetoresistance peculiarities of bismuth wires in high magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Condrea, E., E-mail: condrea@nano.asm.md [Institute of Electronic Engineering and Nanotechnologies, Academy of Science of Moldova, 2028 Chisinau, Republic of Moldova (Moldova, Republic of); International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 51-421 Wroclaw (Poland); Gilewski, A. [International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 51-421 Wroclaw (Poland); MagNet, 50-421 Wroclaw (Poland); Nicorici, A. [Institute of Electronic Engineering and Nanotechnologies, Academy of Science of Moldova, 2028 Chisinau, Republic of Moldova (Moldova, Republic of)

    2016-03-11

    Magnetoresistance measurements of Bi wires performed in the magnetic field oriented along the bisector axis revealed unexpected anomalous peaks in a high magnetic field far above the quantum limit of the electrons. By combining a magnetic field and an uniaxial strain, we obtained a modification of the electronic structure; as a result, the quantum limit for light and heavy electrons is changed in a different way. For the case where heavy electrons are in the quantum limit, a correlation between the exit of the lowest Landau level of light electrons and the Lifshitz transition was found. - Highlights: • Glass-coated single-crystalline Bi wires attain high limit of elastic strain of up to 3.0%. • Selective modification of the electronic structure of Bi wires is obtained by combining a high magnetic field and uniaxial strain. • The correlation between the exit of the lowest Landau level of electrons and Lifshitz transition was found.

  18. Magnetoresistance peculiarities of bismuth wires in high magnetic field

    International Nuclear Information System (INIS)

    Condrea, E.; Gilewski, A.; Nicorici, A.

    2016-01-01

    Magnetoresistance measurements of Bi wires performed in the magnetic field oriented along the bisector axis revealed unexpected anomalous peaks in a high magnetic field far above the quantum limit of the electrons. By combining a magnetic field and an uniaxial strain, we obtained a modification of the electronic structure; as a result, the quantum limit for light and heavy electrons is changed in a different way. For the case where heavy electrons are in the quantum limit, a correlation between the exit of the lowest Landau level of light electrons and the Lifshitz transition was found. - Highlights: • Glass-coated single-crystalline Bi wires attain high limit of elastic strain of up to 3.0%. • Selective modification of the electronic structure of Bi wires is obtained by combining a high magnetic field and uniaxial strain. • The correlation between the exit of the lowest Landau level of electrons and Lifshitz transition was found.

  19. Large field-of-view transmission line resonator for high field MRI

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Johannesson, Kristjan Sundgaard; Boer, Vincent

    2016-01-01

    Transmission line resonators is often a preferable choice for coils in high field magnetic resonance imaging (MRI), because they provide a number of advantages over traditional loop coils. The size of such resonators, however, is limited to shorter than half a wavelength due to high standing wave...... ratio, which leads to inhomogeneous field distribution along the resonator. In this work, it is demonstrated that the resonator length can be extended to over half a wavelength with the help of series capacitors. The approach allows for reduced standing wave ratio and improved field homogeneity....... Achieved magnetic field distribution is compared to the conventional transmission line resonator. Imaging experiments are performed using 7 Tesla MRI system. The developed resonator is useful for building coils with large field-of-view....

  20. Polygenetic magmatism in a monogenetic field: an isotopic investigation from the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    McGee, L.; Beier, C.; Smith, I. E.; Turner, S.

    2009-12-01

    The Auckland Volcanic Field is a Quaternary monogenetic basaltic field of about 50 eruption centres, which have erupted ~4 km3 of magma during the past ~250,000yrs. 2 km3 of this magma has been from Rangitoto Island - the most recent centre (~600yrs BP) - which erupted in two discrete stages ~50 years apart - an intriguing feature for a so-called monogenetic field. Interestingly, the two eruptions produced lavas of different compositions, alkali basalt as the first eruption, and a far more voluminous tholeiite eruption as the second. Trace elements, as well as new U-Th-Ra and Sr-Nd isotopes are used to model the processes which have led to the eruption of two distinct compositions within a small-volume centre, over a short time interval. Rare earth element patterns indicate that both the alkalic and tholeiitic basalts formed in the presence of residual garnet although the amount is higher for the alkali basalt. Differences in degree of melting are also inferred with the alkali basalt requiring a smaller degree than the tholeiite: 2% and 6% respectively. Major elements are used in modelling formation depths and pressures with the alkali basalts requiring a somewhat deeper source than the tholeiites, corresponding well with the larger amount of garnet in the alkali basalt source as modelled by trace elements. (87Sr/86Sr), (143Nd/144Nd) and (238U/232Th) from both eruptions showed the source to have something of a different ‘flavour’ for the two rock types, indicating that the mantle underlying Auckland may be heterogeneous and possibly layered. The constraints from major and trace element data are combined with the U-Th-Ra isotope data to provide an estimate of the melting rates, inferred upwelling rate and conduit length. Higher 230Th-excesses are found in the alkali basalts than the tholeiites, suggesting a longer conduit and/or slower upwelling for the former. Dynamic melting calculations and likely source parameters for the two lavas indicate that the alkali

  1. Low-field versus high-field MRI in diagnosing breast disorders

    International Nuclear Information System (INIS)

    Paeaekkoe, Eija; Reinikainen, Heli; Lindholm, Eija-Leena; Rissanen, Tarja

    2005-01-01

    We evaluated the performance of low-field MRI in breast disorders by comparing it with high-field MRI and biopsy results. Twenty-eight consecutive patients who were able to undergo two magnetic resonance examinations on following days were examined by high-field and low-field MRI. After T1-weighted sagittal images had been obtained a dynamic 3D axial study was performed followed by the acquisition of contrast-enhanced T1-weighted sagittal images. The images were analyzed separately by two radiologists paying attention to lesion morphology and enhancement kinetics. Six patients had problems in both breasts (34 breasts studied). The results were compared with biopsy results of 27 breasts. There were 16 malignant lesions, two fibroadenomas and nine other benign lesions. The inter-magnetic-resonance-scanner κvalue was 0.77 (substantial agreement), while the interobserver κvalue was 0.86 and 0.81 at low and high field, respectively (excellent agreement). The sensitivity was 100 and 100%, the specificity was 82 and 73% and the accuracy was 93 and 89% at low and high field, respectively. The mean lesion size was 2 cm and the smallest malignant lesion was 8 mm in diameter. Low-field MRI is a promising tool for breast imaging. Larger materials and smaller lesions are needed to evaluate its true sensitivity and specificity. (orig.)

  2. Solvothermal synthesis of tin sulfide (SnS) nanorods and investigation of its field emission properties

    Science.gov (United States)

    Bhorde, Ajinkya; Pawbake, Amit; Sharma, Priyanka; Nair, Shruthi; Funde, Adinath; Bankar, Prashant; More, Mahendra; Jadkar, Sandesh

    2018-02-01

    In the present study, we report synthesis of tin sulfide (SnS) nano-rods using a simple solvothermal method at different reaction time period. The formation of single phase SnS has been confirmed by X-ray diffraction (XRD) and Raman analysis. The XRD analysis revealed that the predominant phase in all prepared samples is orthorhombic SnS. The formation of nano-rods of SnS was confirmed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analysis. To investigate the optical properties of SnS nano-rods UV-visible spectroscopy analysis was carried out. We observed that the band gap of SnS nano-rods decreases with increase in reaction time and can be attributed to the quantum confinement effect. Finally, field emission investigations on the SnS nano-rods at the base pressure of 1 × 10- 8 mbar were carried out and found to be superior to the other chalcogenide nanostructures. As-synthesized SnS nano-rods emitter exhibits excellent field emission properties such as low turn-on field ( 2.5 V/µm for 10 µA/ cm2), high emission current density ( 647 µA/cm2 at 3.9 V/µm) and superior current stability ( 5 h for 1 µA). Thus, the facile one-step synthesis approach and robust nature of SnS nano-rods emitter can provide prospects for the future development of large-area emitter applications such as flat-panel-display devices.

  3. High resolution shear wave reflection surveying for hydrogeological investigations

    International Nuclear Information System (INIS)

    Johnson, W.J.; Clark, J.C.

    1992-08-01

    The high resolution S-wave method has been developed to be a powerful tool in mapping subsurface lithology and in conducting groundwater investigations. The research has demonstrated that the resolution obtainable using S-waves in a Coastal Plain environment is more than double than that obtained using conventional reflection, which already offers a higher resolution than any other surface method. Where the mapping of thin clay layers functioning as aquitards or thin sand layers functioning as aquifers are critical to the understanding of groundwater flow, S-wave reflections offer unparalleled possibilities for nondestructive exploration. The field experiment at Cooke Crossroads, South Carolina enabled the detection and mapping of beds in the thickness range of one to three feet. The S-wave reflection technique, in combination with conventional P-wave reflection, has potential to directly detect confined and unconfined aquifers. This is a breakthrough technology that still requires additional research before it can be applied on a commercial basis. Aquifer systems were interpreted from the test data at Cooke Crossroads consistent with theoretical model. Additional research is need in assessing the theoretical response of P- and S-waves to subsurface interfaces within unconsolidated sediments of varying moisture content and lithology. More theoretical modeling and in situ testing are needed to bring our knowledge of these phenomena to the level that oil and gas researchers have done for fluids in sandstones

  4. High-field proton MRS of human brain

    Energy Technology Data Exchange (ETDEWEB)

    Di Costanzo, Alfonso E-mail: alfonso.dicostanzo@unina2.it; Trojsi, F.; Tosetti, M.; Giannatempo, G.M.; Nemore, F.; Piccirillo, M.; Bonavita, S.; Tedeschi, G.; Scarabino, T

    2003-11-01

    Proton magnetic resonance spectroscopy ({sup 1}H-MRS) of the brain reveals specific biochemical information about cerebral metabolites, which may support clinical diagnoses and enhance the understanding of neurological disorders. The advantages of performing {sup 1}H-MRS at higher field strengths include better signal to noise ratio (SNR) and increased spectral, spatial and temporal resolution, allowing the acquisition of high quality, easily quantifiable spectra in acceptable imaging times. In addition to improved measurement precision of N-acetylaspartate, choline, creatine and myo-inositol, high-field systems allow the high-resolution measurement of other metabolites, such as glutamate, glutamine, {gamma}-aminobutyric acid, scyllo-inositol, aspartate, taurine, N-acetylaspartylglutamate, glucose and branched amino acids, thus extending the range of metabolic information. However, these advantages may be hampered by intrinsic field-dependent technical difficulties, such as decreased T2 signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, limitations in the design of homogeneous and sensitive radiofrequency (RF) coils, magnetic field instability and safety issues. Several studies demonstrated that these limitations could be overcome, suggesting that the appropriate optimization of high-field {sup 1}H-MRS would expand the application in the fields of clinical research and diagnostic routine.

  5. Dynamics of colloidal systems of magnetic nanoparticles under influence of magnetic fields investigated by XPCS

    International Nuclear Information System (INIS)

    Schavkan, Alexander

    2017-05-01

    This thesis investigates structural properties and the underlying microscopic dynamics of suspensions of α-FeOOH goethite platelets in water under the influence of magnetic fields. Goethite particles show unusual physical properties and a rich phase diagram, which makes their suspensions an object of high interest for research in the area of ''smart nanoparticles''. Five nanoparticle concentrations were chosen such that different liquid crystal phases could be studied. The suspensions of platelets of these chosen concentrations were exposed to magnetic fields of varying strength. Small angle X-ray scattering and X-ray photon correlation spectroscopy data were taken and evaluated. The appearing phases and phase transitions were studied as a function of concentration and applied magnetic field. For this purpose, order parameters, ellipticity, radial and azimuthal peak positions and widths of scattering features were investigated to clarify the structural properties in detail. For the analysis of the underlying dynamics, the relaxation rates and the shape of measured time correlation functions were evaluated. The results show that with increasing magnetic field a partial realignment of the platelets occurs. This realignment is connected to the magnetic properties of the particles. The dynamics of the corresponding phases revealed a dependence on the concentration of nanoparticles in the suspension. At a concentration of c=20 vol% the transition from the nematic to the anti-nematic phase traverses a mixed state. The nematic and anti-nematic phases show ballistic motion and very similar properties, even though a realignment of the particles from an orientation with the long axis parallel to the applied magnetic field in the nematic phase to an orientation with the long axis perpendicular to the magnetic field in the anti-nematic phase occurs. The mixed state of 20 vol%-suspension exhibits a diffusive motion of the particles and different

  6. Dynamics of colloidal systems of magnetic nanoparticles under influence of magnetic fields investigated by XPCS

    Energy Technology Data Exchange (ETDEWEB)

    Schavkan, Alexander

    2017-05-15

    This thesis investigates structural properties and the underlying microscopic dynamics of suspensions of α-FeOOH goethite platelets in water under the influence of magnetic fields. Goethite particles show unusual physical properties and a rich phase diagram, which makes their suspensions an object of high interest for research in the area of ''smart nanoparticles''. Five nanoparticle concentrations were chosen such that different liquid crystal phases could be studied. The suspensions of platelets of these chosen concentrations were exposed to magnetic fields of varying strength. Small angle X-ray scattering and X-ray photon correlation spectroscopy data were taken and evaluated. The appearing phases and phase transitions were studied as a function of concentration and applied magnetic field. For this purpose, order parameters, ellipticity, radial and azimuthal peak positions and widths of scattering features were investigated to clarify the structural properties in detail. For the analysis of the underlying dynamics, the relaxation rates and the shape of measured time correlation functions were evaluated. The results show that with increasing magnetic field a partial realignment of the platelets occurs. This realignment is connected to the magnetic properties of the particles. The dynamics of the corresponding phases revealed a dependence on the concentration of nanoparticles in the suspension. At a concentration of c=20 vol% the transition from the nematic to the anti-nematic phase traverses a mixed state. The nematic and anti-nematic phases show ballistic motion and very similar properties, even though a realignment of the particles from an orientation with the long axis parallel to the applied magnetic field in the nematic phase to an orientation with the long axis perpendicular to the magnetic field in the anti-nematic phase occurs. The mixed state of 20 vol%-suspension exhibits a diffusive motion of the particles and different

  7. Field Investigation of an Air-Source Cold Climate Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2017-01-01

    In the U.S., there are approximately 2.6 million dwellings that use electricity for heating in cold and very cold regions with an annual energy consumption of 0.16 quads (0.17 EJ). A high performance cold climate heat pump (CCHP) would result in significant savings over current technologies (greater than 60% compared to electric resistance heating). We developed an air-source cold climate heat pump, which uses tandem compressors, with a single compressor rated for the building design cooling load, and running two compressors to provide, at -13 F (-25 C), 75% of rated heating capacity. The tandem compressors were optimized for heating operation and are able to tolerate discharge temperatures up to 280 F (138 C). A field investigation was conducted in the winter of 2015, in an occupied home in Ohio, USA. During the heating season, the seasonal COP was measured at 3.16, and the heat pump was able to operate down to -13 F (-25 C) and eliminate resistance heat use. The heat pump maintained an acceptable comfort level throughout the heating season. In comparison to a previous single-speed heat pump in the home, the CCHP demonstrated more than 40% energy savings in the peak heating load month. This paper illustrates the measured field performance, including compressor run time, frost/defrosting operations, distributions of building heating load and capacity delivery, comfort level, field measured COPs, etc.

  8. Properties of partially ionized hydrogen plasmas in high electric fields

    International Nuclear Information System (INIS)

    Morawetz, K.

    1993-03-01

    In this thesis the fundamental equations of many-particle quantum-statistics of nonequilibrium are treated in respect to arbitrary high electric fields. Generalizations are found for the T-matrix approximation as well as for the shielded potential approximation valid for any field strength. These result in a non-Markovian behavior of the obtained collision integrals, also known as intra-collisional-field-effect (ICFE), and in a broadening of the energy conservation, the so-called collisional broadening (CB), caused by applied electric fields. In linear response it is shown in a new way, how the Debye-Onsager relaxation effect can be rederived from these collision integrals. Furthermore the complete quantum result is presented. Both effects, ICFE and CB, contribute to the right classical limit. The quantum result yields an surprising maximum of this field effects in dependence of the interacting mass ratio, which may be important in exciton-plasmas and semiconductors. (orig.)

  9. High School Students Group Interaction with the Electric Field Hockey Interactive Simulation

    OpenAIRE

    Cao, Ying

    2017-01-01

    This study investigates a group of high school students in a physics classroom interacting with a computer simulation that simulates the electrostatic interaction as a hockey game, the Electric Field Hockey. The activity featured in this study took place prior to the students receiving formal instruction about the electric field. The learning goal was to allow students to explore the simulated electrostatic phenomena. The study asks the following research question: How do high school students...

  10. Investigation of the stability of polysilicon layers in SOI-structures under irradiation by electrons and hard magnetic field influence

    Directory of Open Access Journals (Sweden)

    Khoverko Yu. N.

    2010-10-01

    Full Text Available The properties of recrystallized polysilicon on insulator layers of p-type conductive SOI-structures with different carrier concentration irradiated with high-energy electrons flow about 1017 сm–2 in temperature range 4,2—300 К and high magnetic fields were investigated. It was found that heavily doped laser recrystallized polysilicon on insulator layers show its radiation resistance under irradiation with high-energy electrons and magnetoresistance of such material remains quite low in magnetic field about 14 T does not exceed 1—2%. Such qulity can be applied in designing of microelectronic sensors of mechanical values operable in hard conditions of exploitation.

  11. A design proposal for high field dipole magnet

    International Nuclear Information System (INIS)

    Hirabayashi, H.; Kobayashi, M.; Shintomi, T.; Tsuchiya, K.; Wake, M.

    1981-06-01

    A design of the high field dipole magnet which is going to be constructed in the KEK-Fermilab collaboration program is proposed. The central field of the magnet is meant to achieve 10 T by the use of ternary alloy conductor in the 1.8 K superfluid environment under atmospheric pressure. Since the electro-magnetic force in such a high field region is strong enough to give a fatal problem, a careful calculation is necessary for the magnet design. The program POISSON and LINDA were used for the magnetic field calculation. The computer code ISAS which is originated from NASTRAN developed at NASA was applied to calculate the stress and the deformation. A horizontal cryostat desigh for the operation of the 10 T dipole magnet is also proposed. (author)

  12. MR equipment acquisition strategies: low-field or high-field scanners

    International Nuclear Information System (INIS)

    Marti-Bonmati, L.; Kormano, M.

    1997-01-01

    Magnetic resonance (MR) field strength is one of the key aspects to consider when purchasing MR equipment. Other aspects include the gradient system, coil design, computer and pulse sequence availability, purchase cost, local reimbursement policies, and current opinion within the medical community. Our objective here is to evaluate the decision-influencing aspects of the MR market, with a focus on some specific areas such as high resolution studies, examination times, special techniques, instrumentation, open design magnets, costs and reimbursement policies, academic and industrial interests, contrast media, clinical efficacy, and finally, clinicians' preferences. Certainly the advantage of high-field is a higher signal-to-noise ratio and improved resolution. With a high-field unit, higher spatial resolution images and higher temporal resolution images can be obtained. Typical imaging times needed to produce clinically diagnostic images are about 3 times longer at 0.1 T than at 1.0 or 1.5 T. High-field-related advanced techniques, such as functional imaging, spectroscopy and microscopy, may become clinically useful in the near future. As long as there is an unlimited demand for MR examinations, it appears financially profitable to run a high-field system, despite the associated higher costs. However, if demand for MR becomes saturated, low-field systems will cause less financial strain on the reimbursement organisation and service provider. Recent emphasis on cost containment, the development of interventional techniques, the increased use of MR for patients in intensive care and operating suites, the deployment of magnets in office suites, and the development of new magnet configurations, all favour the supplementary use of low-field systems. Hence, MR units of all field strengths have a role in radiology. (orig.)

  13. Artificial terraced field extraction based on high resolution DEMs

    Science.gov (United States)

    Na, Jiaming; Yang, Xin; Xiong, Liyang; Tang, Guoan

    2017-04-01

    With the increase of human activities, artificial landforms become one of the main terrain features with special geographical and hydrological value. Terraced field, as the most important artificial landscapes of the loess plateau, plays an important role in conserving soil and water. With the development of digital terrain analysis (DTA), there is a current and future need in developing a robust, repeatable and cost-effective research methodology for terraced fields. In this paper, a novel method using bidirectional DEM shaded relief is proposed for terraced field identification based on high resolution DEM, taking Zhifanggou watershed, Shannxi province as the study area. Firstly, 1m DEM is obtained by low altitude aerial photogrammetry using Unmanned Aerial Vehicle (UAV), and 0.1m DOM is also obtained as the test data. Then, the positive and negative terrain segmentation is done to acquire the area of terraced field. Finally, a bidirectional DEM shaded relief is simulated to extract the ridges of each terraced field stages. The method in this paper can get not only polygon feature of the terraced field areas but also line feature of terraced field ridges. The accuracy is 89.7% compared with the artificial interpretation result from DOM. And additional experiment shows that this method has a strong robustness as well as high accuracy.

  14. A commercial tokamak reactor using super high field superconducting magnets

    International Nuclear Information System (INIS)

    Schwartz, J.; Bromberg, L.; Cohn, D.R.; Williams, J.E.C.

    1988-01-01

    This paper explores the range of possibilities for producing super high fields with advanced superconducting magnets. Obtaining magnetic fields greater than about 18 T at the coil in a large superconducting magnet system will require advances in many areas of magnet technology. These needs are discussed and potential solutions (advanced superconductors, structural materials and design methods) evaluated. A point design for a commercial reactor with magnetic field at the coil of 24 T and fusion power of 1800 MW is presented. Critical issues and parameters for magnet design are identified. 20 refs., 9 figs., 4 tabs

  15. Ionization of highly excited hydrogen atoms by intense electromagnetic fields

    International Nuclear Information System (INIS)

    Gersten, J.; Mittleman, M.H.

    1975-01-01

    A previous theory of atomic transition in ultrastrong electromagnetic fields is applied to the problem of the ionization of highly excited hydrogen atoms. The magnitude of the fields necessary for the validity of the theory is greatly reduced by using excited hydrogen in the initial state, and the requirement of only multiphoton ionization limits the application to low frequency (microwave) fields. The requirement can probably be satisfied with currently available equipment. A result of the calculation is that the average number of photons absorbed is twice the minimum number. (U.S.)

  16. Nonlinear piezoelectricity in epitaxial ferroelectrics at high electric fields.

    Science.gov (United States)

    Grigoriev, Alexei; Sichel, Rebecca; Lee, Ho Nyung; Landahl, Eric C; Adams, Bernhard; Dufresne, Eric M; Evans, Paul G

    2008-01-18

    Nonlinear effects in the coupling of polarization with elastic strain have been predicted to occur in ferroelectric materials subjected to high electric fields. Such predictions are tested here for a PbZr0.2Ti0.8O3 ferroelectric thin film at electric fields in the range of several hundred MV/m and strains reaching up to 2.7%. The piezoelectric strain exceeds predictions based on constant piezoelectric coefficients at electric fields from approximately 200 to 400 MV/m, which is consistent with a nonlinear effect predicted to occur at corresponding piezoelectric distortions.

  17. Magnetoresistance peculiarities of bismuth wires in high magnetic field

    Science.gov (United States)

    Condrea, E.; Gilewski, A.; Nicorici, A.

    2016-03-01

    Magnetoresistance measurements of Bi wires performed in the magnetic field oriented along the bisector axis revealed unexpected anomalous peaks in a high magnetic field far above the quantum limit of the electrons. By combining a magnetic field and an uniaxial strain, we obtained a modification of the electronic structure; as a result, the quantum limit for light and heavy electrons is changed in a different way. For the case where heavy electrons are in the quantum limit, a correlation between the exit of the lowest Landau level of light electrons and the Lifshitz transition was found.

  18. Far Field Extrapolation from Near Field Interactions and Shielding Influence Investigations Based on a FE-PEEC Coupling Method

    Directory of Open Access Journals (Sweden)

    Gérard Meunier

    2013-03-01

    Full Text Available Regarding standards, it is well established that common mode currents are the main source of far field emitted by variable frequency drive (VFD-cable-motor associations. These currents are generated by the combination of floating potentials with stray capacitances between these floating potential tracks and the mechanical parts connected to the earth (the heatsink or cables are usual examples. Nowadays, due to frequency and power increases, the systematic compliance to EMC (ElectroMagnetic Compatibility becomes increasingly difficult and costly for industrials. As a consequence, there is a well-identified need to investigate practical and low cost solutions to reduce the radiated fields of VFD-cable-motor associations. A well-adapted solution is the shielding of wound components well known as the major source of near magnetic field. However, this solution is not convenient, it is expensive and may not be efficient regarding far field reduction. Optimizing the components placement could be a better and cheaper solution. As a consequence, dedicated tools have to be developed to efficiently investigate not easy comprehendible phenomena and finally to control EMC disturbances using component placement, layout geometry, shielding design if needed. However, none of the modeling methods usually used in industry complies with large frequency range and far field models including magnetic materials, multilayer PCBs, and shielding. The contribution of this paper is to show that alternatives regarding modeling solutions exist and can be used to get in-deep analysis of such complex structures. It is shown in this paper that near field investigations can give information on far field behavior. It is illustrated by an investigation of near field interactions and shielding influence using a FE-PEEC hybrid method. The test case combining a common mode filter with the floating potentials tracks of an inverter is based on an industrial and commercialized VFD. The

  19. Design considerations for a large aperture high field superconducting dipole

    Energy Technology Data Exchange (ETDEWEB)

    Harfoush, F.; Ankenbrandt, C.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T.; Riddiford, A.; Theilacker, J.

    1989-03-01

    The final phase of the Fermilab upgrade proposal calls for a new ring of superconducting magnets to be placed in the existing Main Accelerator tunnel. The goal of this design study is to specify a high field dipole (HFD) that is capable of supporting fixed target operation (ramping, resonant extraction) at a field of 6.6T (1.5 Tev) and colliding beam physics at 8.0T (1.8 Tev). The magnetic field quality at high field is set by the large amplitude orbits associated with resonant extraction. The field quality must therefore be at least as good as the existing Tevatron magnets which fulfill these criteria. The high fields and large aperture of this magnet result in large forces on the coil and collar assemblies. Therefore, the cold mass design must be able to sustain these forces while providing sufficient cooling to the coils during 4.2 K fixed target operation, and a minimum heat load during 1.8 K collider operation. The design work is still in progress but a cosine-theta, cold-iron dipole with a 70mm inner diameter coil has been tentatively adopted. This report presents details on the conductor and cable parameters, coil cross-section, projected manufacturing tolerances, iron yoke design, and cold mass assembly. 4 refs., 5 figs., 1 tab.

  20. Design considerations for a large aperture high field superconducting dipole

    International Nuclear Information System (INIS)

    Harfoush, F.; Ankenbrandt, C.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T.; Riddiford, A.; Theilacker, J.

    1989-03-01

    The final phase of the Fermilab upgrade proposal calls for a new ring of superconducting magnets to be placed in the existing Main Accelerator tunnel. The goal of this design study is to specify a high field dipole (HFD) that is capable of supporting fixed target operation (ramping, resonant extraction) at a field of 6.6T (1.5 Tev) and colliding beam physics at 8.0T (1.8 Tev). The magnetic field quality at high field is set by the large amplitude orbits associated with resonant extraction. The field quality must therefore be at least as good as the existing Tevatron magnets which fulfill these criteria. The high fields and large aperture of this magnet result in large forces on the coil and collar assemblies. Therefore, the cold mass design must be able to sustain these forces while providing sufficient cooling to the coils during 4.2 K fixed target operation, and a minimum heat load during 1.8 K collider operation. The design work is still in progress but a cosine-theta, cold-iron dipole with a 70mm inner diameter coil has been tentatively adopted. This report presents details on the conductor and cable parameters, coil cross-section, projected manufacturing tolerances, iron yoke design, and cold mass assembly. 4 refs., 5 figs., 1 tab

  1. Modification of the magnetic field structure of high-beta plasmas with a perturbation field in the Large Helical Device

    International Nuclear Information System (INIS)

    Sakakibara, S; Suzuki, Y; Narushima, Y; Watanabe, K Y; Ohdachi, S; Ida, K; Yoshinuma, M; Narihara, K; Yamada, I; Tanaka, K; Tokuzawa, T; Yamada, H; Takemura, Y

    2013-01-01

    The effect of resonant magnetic perturbation (RMP) on MHD characteristics is investigated in high-beta plasmas of the Large Helical Device. The ramp-up and static m/n = 1/1 RMP field are applied in medium- (∼2%) and high- (∼4%) beta plasmas in order to find beta dependences of mode penetration, MHD activities and confinement. The results show that the threshold of mode penetration linearly increases with the beta value and/or plasma collisionality. The threshold of mode penetration in the RMP ramp-up experiments is roughly consistent with the static RMP case. The beta value gradually decreases with the RMP field strength before mode penetration, which is caused by a reduction in the pressure inside the ι/2π = 1 resonance. The width of the magnetic island after the penetration becomes larger than the given RMP field, and it is further enhanced by the increment of the beta value. (paper)

  2. Effect of high-frequency electromagnetic fields on trophoblastic connexins.

    Science.gov (United States)

    Cervellati, Franco; Franceschetti, Guido; Lunghi, Laura; Franzellitti, Silvia; Valbonesi, Paola; Fabbri, Elena; Biondi, Carla; Vesce, Fortunato

    2009-07-01

    Connexins (Cx) are membrane proteins able to influence trophoblast functions. Here we investigated the effect of high-frequency electromagnetic fields (HF-EMF) on Cx expression and localization in extravillous trophoblast cell line HTR-8/SVneo. We also analysed cell ultrastructural changes induced by HF-EMF exposure. Samples were exposed to pulse-modulated 1817 MHz sinusoidal waves (GSM-217 Hz; 1h: SAR of 2 W/kg). Cx mRNA expression was assessed through semi-quantitative RT-PCR, protein expression by Western blotting, protein localization by indirect immunofluorescence, cell ultrastructure using electron microscopy. HF-EMF exposure significantly and selectively increased Cx40 and Cx43, without altering protein expression. Nevertheless, Cx40 and Cx43 lost their punctuate fluorescence within the cell membrane, becoming diffuse after HF-EMF exposure. Electron microscopy evidenced a sharp decrease in intercellular gap junction-like structures. This study is the first to indicate that exposure of extravillous trophoblast to GSM-217 Hz signals can modify Cx gene expression, Cx protein localization and cellular ultrastructure.

  3. Microscopic neutron investigation of the Abrikosov state of high ...

    Indian Academy of Sciences (India)

    reveal the existence of a magnetic field-induced phase transition from a hexagonal to a square coordination of the ... Introduction. Apart from the unusual electronic and magnetic behaviour of the cuprate high- temperature ... are visualized in figure 3. In order to lift this apparent contradiction, Nakai et al [8], based on photoe-.

  4. The Consistency Of High Attorney Of Papua In Corruption Investigation

    Directory of Open Access Journals (Sweden)

    Samsul Tamher

    2015-08-01

    Full Text Available This study aimed to determine the consistency of High Attorney of Papua in corruption investigation and efforts to return the state financial loss. The type of study used in this paper is a normative-juridical and empirical-juridical. The results showed that the High Attorney of Papua in corruption investigation is not optimal due to the political interference on a case that involving local officials so that the High Attorney in decide the case is not accordance with the rule of law. The efforts of the High Attorney of Papua to return the state financial loss through State Auction Body civil- and criminal laws.

  5. Development and Testing of UCLA's Electron Losses and Fields Investigation (ELFIN) Instrument Payload

    Science.gov (United States)

    Wilkins, C.; Bingley, L.; Angelopoulos, V.; Caron, R.; Cruce, P. R.; Chung, M.; Rowe, K.; Runov, A.; Liu, J.; Tsai, E.

    2017-12-01

    UCLA's Electron Losses and Fields Investigation (ELFIN) is a 3U+ CubeSat mission designed to study relativistic particle precipitation in Earth's polar regions from Low Earth Orbit. Upon its 2018 launch, ELFIN will aim to address an important open question in Space Physics: Are Electromagnetic Ion-Cyclotron (EMIC) waves the dominant source of pitch-angle scattering of high-energy radiation belt charged particles into Earth's atmosphere during storms and substorms? Previous studies have indicated these scattering events occur frequently during storms and substorms, and ELFIN will be the first mission to study this process in-situ.Paramount to ELFIN's success is its instrument suite consisting of an Energetic Particle Detector (EPD) and a Fluxgate Magnetometer (FGM). The EPD is comprised of two collimated solid-state detector stacks which will measure the incident flux of energetic electrons from 50 keV to 4 MeV and ions from 50 keV to 300 keV. The FGM is a 3-axis magnetic field sensor which will capture the local magnetic field and its variations at frequencies up to 5 Hz. The ELFIN spacecraft spins perpendicular to the geomagnetic field to provide 16 pitch-angle particle data sectors per revolution. Together these factors provide the capability to address the nature of radiation belt particle precipitation by pitch-angle scattering during storms and substorms.ELFIN's instrument development has progressed into the late Engineering Model (EM) phase and will soon enter Flight Model (FM) development. The instrument suite is currently being tested and calibrated at UCLA using a variety of methods including the use of radioactive sources and applied magnetics to simulate orbit conditions during spin sectoring. We present the methods and test results from instrument calibration and performance validation.

  6. Experimental investigation of flow field in a laboratory-scale compressor

    Directory of Open Access Journals (Sweden)

    Hongwei Ma

    2017-02-01

    Full Text Available The inner flow environment of turbomachinery presents strong three-dimensional, rotational, and unsteady characteristics. Consequently, a deep understanding of these flow phenomena will be the prerequisite to establish a state-of-the-art design system of turbomachinery. Currently the development of more accurate turbulence models and CFD tools is in urgent need for a high-quality database for validation, especially the advanced CFD tools, such as large eddy simulation (LES. Under this circumstance, this paper presents a detailed experimental investigation on the 3D unsteady flow field inside a laboratory-scale isolated-rotor with multiple advanced measurement techniques, including traditional aerodynamic probes, hotwire probes, unsteady endwall static pressure measurement, and stereo particle image velocimetry (SPIV. The inlet boundary layer profile is measured with both hotwire probe and aerodynamic probe. The steady and unsteady flow fields at the outlet of the rotor are measured with a mini five-hole probe and a single-slanted hotwire probe. The instantaneous flow field in the rotor tip region inside the passage is captured with SPIV, and then a statistical analysis of the spatial distribution of the instantaneous tip leakage vortex/flow is performed to understand its dynamic characteristics. Besides these, the uncertainty analysis of each measurement technique is described. This database is quite sufficient to validate the advanced numerical simulation with LES. The identification process of the tip leakage vortex core in the instantaneous frames obtained from SPIV is performed deliberately. It is concluded that the ensemble-averaged flow field could not represent the tip leakage vortex strength and the trajectory trace. The development of the tip leakage vortex could be clearly cataloged into three phases according to their statistical spatial distribution. The streamwise velocity loss induced by the tip leakage flow increases until the

  7. Electron transport in bulk GaN under ultrashort high-electric field transient

    Science.gov (United States)

    Korotyeyev, V. V.; Kochelap, V. A.; Kim, K. W.

    2011-10-01

    We have investigated nonlinear electron transport in GaN induced by high-electric field transients by analyzing the temporal dependence of the electron drift velocity and temperature. For picosecond transients, our calculations have established that the electron dynamics retain almost all the features of the steady-state velocity-field characteristics including the portion with negative differential conductivity. It was also found that transient currents in GaN samples give rise to the THz re-emission effect—radiation of electromagnetic field, temporal and spectral properties of which directly relate to the velocity-field characteristics of the sample. The results clearly indicate that existing methods for the generation of high-electric field transients and subpicosecond signal measurements can be applied to the characterization of hot electron transport at ultrahigh fields while avoiding Joule self-heating, hot phonon accumulation and other undesirable effects.

  8. Electrical insulation characteristics of liquid helium under high speed rotating field

    International Nuclear Information System (INIS)

    Ishii, I.; Fuchino, S.; Okano, M.; Tamada, N.

    1996-01-01

    Electrical breakdown behavior of liquid helium was investigated under high speed rotating field. In the development of superconducting turbine generator it is essential to get the knowledge of electrical insulation characteristics of liquid helium under high speed rotating field. When the current of the field magnet of a superconducting generator is changed, changing magnetic field generates heat in the conductor and it causes bubbles in the liquid helium around the conductor. The behavior of the bubbles is affected largely by the buoyancy which is generated by the centrifugal force. Electrical breakdown behavior of the liquid helium is strongly dependent on the gas bubbles in the liquid. Electrical breakdown voltage between electrodes was measured in a rotating cryostat with and without heater input for bubble formation. Decrease of the breakdown voltage by the heater power was smaller in the rotating field than that in the non rotating field

  9. A High School Statistics Class Investigates the Death Penalty

    Science.gov (United States)

    Brelias, Anastasia

    2015-01-01

    Recommendations for reforming high school mathematics curricula emphasize the importance of engaging students in mathematical investigations of societal issues (CCSSI [Common Core State Standards Initiative] 2010; NCTM [National Council of Teachers of Mathematics] 2000). Proponents argue that these investigations can positively influence students'…

  10. Investigation of Nursery Rhymes According to the Classification of Semantic Fields and Values

    Science.gov (United States)

    Dinçel, Betül Keray

    2017-01-01

    Nursery rhymes are quite important in terms of developing children's language skills. It was observed that there is a paucity of research looking at semantic fields and value regarding nursery rhymes; therefore, this study was intended to fill that gap in the literature by investigating nursery rhymes in terms of semantic fields and value. In this…

  11. Detailed investigation of the conducting channel in poly(3-hexylthiophene) field effect transistors

    NARCIS (Netherlands)

    von Hauff, Elizabeth; Johnen, Fabian; Tunc, Ali Veysel; Govor, Leonid; Parisi, Juergen

    2010-01-01

    In this study, the conducting channel in poly(3-hexylthiophene) (P3HT) organic field effect transistors (OFETs) was investigated. The effect of varying the P3HT layer thickness on the OFET parameters was studied. The threshold voltage and the field effect mobility were determined from both the

  12. Investigation of the Decelerating Field of an Electron Multiplier under Negative Ion Impact

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Kjeldgaard, K.

    1973-01-01

    The effect of the decelerating field of an electron multiplier towards negative ions was investigated under standard mass spectrometric conditions. Diminishing of this decelerating field by changing of the potential of the electron multiplier increased the overall sensitivity to negative ions...

  13. Study of HTS Wires at High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Turrioni, D.; Barzi, E.; Lamm, M.J.; Yamada, R.; Zlobin, A.V.; Kikuchi, A.; /Fermilab

    2009-01-01

    Fermilab is working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting (HTS) materials is being considered for these magnets using Helium refrigeration. Critical current (I{sub c}) measurements of HTS conductors were performed at FNAL and at NIMS up to 28 T under magnetic fields at zero to 90 degree with respect to the sample face. A description of the test setups and results on a BSCCO-2223 tape and second generation (2G) coated conductors are presented.

  14. Diffusion of minority carriers against electric field (high injection level)

    Science.gov (United States)

    Gert, A. V.; Dmitriev, A. P.; Levinshtein, M. E.; Yuferev, V. S.; Palmour, J. W.

    2017-11-01

    A one-dimensional analytic model describing the motion of minority carriers against the electric field direction under the conditions of high injection level is developed. The results of the model can also be used to estimate the motion of carriers against the field in the case of an arbitrary injection level. The model makes it possible to describe, in good agreement with the results of computer simulation, the modulation of the collector layer resistance in a high voltage SiC bipolar transistor.

  15. Highly nonparaxial (1+1)-D subwavelength optical fields.

    Science.gov (United States)

    Rizza, C; Ciattoni, A; Palange, E

    2010-04-12

    A general approach for describing (1+1)-D subwavelength optical field whose waist is much smaller than the wavelength is presented. Exploiting the vectorial Rayleigh-Sommerfeld diffraction theory, a suitable expansion in the ratio between the beam waist and the wavelength allows us to prove the a (1+1)D highly nonparaxial field is generally the product of a cylindrical wave carrier and an envelope which is angularly slowly varying. We apply our general approach to the case of highly nonparaxial Hermite-Gaussian beams whose description is fully analytical.

  16. High-pressure Moessbauer spectroscopy of perovskite high valence iron oxides under external magnetic field

    International Nuclear Information System (INIS)

    Kawakami, Takateru; Nasu, Saburo

    2005-01-01

    The magnetic properties of SrFeO 3 (SFO), CaFeO 3 (CFO) and Sr 2/3 La 1/3 FeO 3 (SLFO), which are perovskite iron oxides with a high valence state of Fe, have been investigated by high-pressure Moessbauer spectroscopy under external magnetic field. These perovskite oxides have been found to switch electronic ground state drastically from the antiferromagnetic (AF) state to the ferromagnetic (FM) state under high pressure. CFO and SLFO, which show a charge-disproportionation (CD: 2Fe 4+ → Fe 3+ + Fe 5+ and 3Fe 11/3+ → 2Fe 3+ + Fe 5+ , respectively) at low temperature, switch magnetic ordering from the AF state to the FM state simultaneously with the suppression of the CD in a critical pressure of about 19 and 23 GPa, respectively. SFO, which does not show any CD, switches its magnetic ordering from the AF state to the FM state at about 7 GPa. These pressure-induced transitions from the AF state to the FM state are accompanied by the discontinuous reduction of the magnetic hyperfine fields

  17. Investigation of acoustic field near to elastic thin plate using integral method

    Directory of Open Access Journals (Sweden)

    В.І. Токарев

    2004-01-01

    Full Text Available  Investigation of acoustic field near to elastic thin plate using  integral method The influence of boundary conditions on sound wave propagation, radiation and transmission through thin elastic plate is investigated. Necessary for that numerical model was found using the Helmholtz equation and equation of oscilated plate by means of integral formulation of the solution for acoustic fields near to elastic thin plate and for bending waves of small amplitudes.

  18. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  19. Anisotropic transport properties of quasiballistic InAs nanowires under high magnetic field

    Science.gov (United States)

    Vigneau, Florian; Zeng, Zaiping; Escoffier, Walter; Caroff, Philippe; Leturcq, Renaud; Niquet, Yann-Michel; Raquet, Bertrand; Goiran, Michel

    2018-03-01

    The magnetoconductance of a long channel InAs nanowire based field effect transistor in the quasiballistic regime under large magnetic field is investigated. The quasi-1D nanowire is fully characterized by a bias voltage spectroscopy and measurements under magnetic field up to 50 T applied either perpendicular or parallel to the nanowire axis lifting the spin and orbital degeneracies of the subbands. Under normal magnetic field, the conductance shows quantized steps due to the backscattering reduction and a decrease due to depopulation of the 1D modes. Under axial magnetic field, a quasioscillatory behavior is evidenced due to the coupling of the magnetic field with the angular momentum of the wave function. In addition the formation of cyclotron orbits is highlighted under high magnetic field. The experimental results are compared with theoretical calculation of the 1D band structure and related parameters.

  20. Numerical and experimental investigations of coupled electromagnetic and thermal fields in superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Mierau, Anna

    2013-01-01

    The new international facility for antiproton and ion research FAIR will be built in Darmstadt (Germany). The existing accelerator facility of GSI Helmholtzzentrum for Heavy Ion Research will serve as a pre-accelerator for the new facility. FAIR will provide high-energy antiproton and ion beams with unprecedented intensity and quality for fundamental research of states of matter and the evolution of the universe. The central component of FAIR's accelerator and storage rings complex is a double-ring accelerator consisting of two heavy ion synchrotrons SIS100 and SIS300. The SIS100 is the primary accelerator of FAIR. The desired beam properties of SIS100 require a design of the machine much more challenging than the conventional design of existing proton and ion synchrotrons. The key technical components of each synchrotron are the special electromagnets, which allow guiding the charged particles on their orbits in the synchrotron during the acceleration processes. For a stable operation of the SIS100's the magnets have to produce extremely homogeneous magnetic fields. Furthermore, the SIS100 high-intensity ion beam modes, for example with U 28+ ions, require an ultra-high vacuum in the beam pipe of the synchrotron, which can be generated effectively only at low temperatures below 15 K. Due to the field quality requirements for the magnets, the properties of the dynamic vacuum in the beam pipe but also in order to minimise future operating costs, fast ramped superconducting magnets will be used to guide the beam in SIS100. These magnets have been developed at GSI within the framework of the FAIR project. Developing a balanced design of a superconducting accelerator magnet requires a sound understanding of the interaction between its thermal and electromagnetic fields. Of special importance in this case are the magnetic field properties such as the homogeneity of the static magnetic field in the aperture of the magnet, and the dynamic heat losses of the whole magnet

  1. Experimental Investigation of Properties of Foam Concrete for Industrial Floors in Testing Field

    Science.gov (United States)

    Vlcek, Jozef; Drusa, Marian; Scherfel, Walter; Sedlar, Bronislav

    2017-12-01

    Foam concrete (FC), as a mixture of cement, water, additives and technical foam, is well known for more than 30 years. It is building material with good mechanical properties, low thermal conductivity, simple and even high technological treatment. Foam concrete contains closed void pores, what allows achieving low bulk density and spare of raw materials. Thanks to its properties, it is usable as a replacement of conventional subbase layers of the industrial floors, the transport areas or as a part of the foundation structures of the buildings. Paper presents the preparation of the testing field (physical model) which was created for experimental investigation of the foam concrete subbase layer of the industrial floor in a real scale.

  2. Microbiological investigations after the ``Bravo'' blowout (Ekofisk oil field, North Sea)

    Science.gov (United States)

    Gunkel, W.; Pedersen, S.; Dundas, I.; Eimhjellen, K.

    1985-03-01

    Following the accident in 1977 at an offshore oil producing platform in the Ekofisk oil field (North Sea) an estimated amount of 13000 15000 tons of oil polluted the sea. Microbiological investigations were conducted one to five weeks after the blowout and compared with data collected in the same area during the years before. Bacterial numbers in the water were fairly low. In the floating oil particles, however, extremely high values were obtained (2 × 1011 heterotrophic bacteria 1-1 and 5 × 1010 oil degrading bacteria 1-1). The data on oxygen consumption gave markedly different results indicating that the oil degradation potential of the water seemed to vary widely from one station to another. The greatest increase in oxygen consumption (following the addition of oil to the bottles) occurred in samples taken at the station where oil particles from the blowout were observed floating on the surface. This indicates a higher oil degradation potential.

  3. Theoretical investigation of performance of armchair graphene nanoribbon field effect transistors

    Science.gov (United States)

    Hur, Ji-Hyun; Kim, Deok-Kee

    2018-05-01

    In this paper, we theoretically investigate the highest possible expected performance for graphene nanoribbon field effect transistors (GNRFETs) for a wide range of operation voltages and device structure parameters, such as the width of the graphene nanoribbon and gate length. We formulated a self-consistent, non-equilibrium Green’s function method in conjunction with the Poisson equation and modeled the operation of nanometer sized GNRFETs, of which GNR channels have finite bandgaps so that the GNRFET can operate as a switch. We propose a metric for competing with the current silicon CMOS high performance or low power devices and explain that this can vary greatly depending on the GNRFET structure parameters.

  4. 3D-QSAR Investigation of Synthetic Antioxidant Chromone Derivatives by Molecular Field Analysis

    Directory of Open Access Journals (Sweden)

    Jiraporn Ungwitayatorn

    2008-02-01

    Full Text Available A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR studies using molecular field analysis (MFA. The substitutional requirements for favorable antioxidant activity were investigated and a predictive model that could be used for the design of novel antioxidants was derived. Regression analysis was carried out using genetic partial least squares (G/PLS method. A highly predictive and statistically significant model was generated. The predictive ability of the developed model was assessed using a test set of 5 compounds (r2pred = 0.924. The analyzed MFA model demonstrated a good fit, having r2 value of 0.868 and crossvalidated coefficient r2cv value of 0.771.

  5. The Science and Technology Case for High-Field Fusion

    Science.gov (United States)

    Whyte, D.

    2017-10-01

    This review will focus on the origin, development and new opportunities of a strategy for fusion energy based on the high-field approach. In this approach confinement devices are designed at the maximum possible value of vacuum magnetic field strength, B. The integrated electrical, mechanical and cooling engineering challenges of high-field on coil (Bcoil) , large-bore electromagnets are examined for both copper and superconductor materials. These engineering challenges are confronted because of the profound science advantages provided by high-B, which are derived and reviewed: high fusion power density, B4, in compact devices, thermonuclear plasmas with significant stability margin, and, in tokamaks, access to higher plasma density. Two distinct high-field strategies emerged in the 1980's. The first was compact, cryogenically-cooled copper devices (BPX, IGNITOR, FIRE) with Bcoil>20 T, while the second was a large-volume, Nb3Sn superconductor device with Bcoil Copper Oxide (REBCO) superconductor-based devices with Bcoil >20 T; a strategy that essentially combines the best components of the two previous strategies. Recent activities examining the technology and science implications of this new strategy are reviewed. On the technology side, REBCO superconductors have now been used to produce Bcoil>40 T in small-bore electromagnets, enabled by rapid progress in manufactured REBCO conductor quality, coil modularity and flexible operating temperature range. Specific tokamak designs, over a range of aspect ratios, have been developed to take scientific advantage of these features in various ways, and will be described.

  6. Low-field MRI can be more sensitive than high-field MRI

    Science.gov (United States)

    Coffey, Aaron M.; Truong, Milton L.; Chekmenev, Eduard Y.

    2013-12-01

    MRI signal-to-noise ratio (SNR) is the key factor for image quality. Conventionally, SNR is proportional to nuclear spin polarization, which scales linearly with magnetic field strength. Yet ever-stronger magnets present numerous technical and financial limitations. Low-field MRI can mitigate these constraints with equivalent SNR from non-equilibrium ‘hyperpolarization' schemes, which increase polarization by orders of magnitude independently of the magnetic field. Here, theory and experimental validation demonstrate that combination of field independent polarization (e.g. hyperpolarization) with frequency optimized MRI detection coils (i.e. multi-turn coils using the maximum allowed conductor length) results in low-field MRI sensitivity approaching and even rivaling that of high-field MRI. Four read-out frequencies were tested using samples with identical numbers of 1H and 13C spins. Experimental SNRs at 0.0475 T were ∼40% of those obtained at 4.7 T. Conservatively, theoretical SNRs at 0.0475 T 1.13-fold higher than those at 4.7 T were possible despite an ∼100-fold lower detection frequency, indicating feasibility of high-sensitivity MRI without technically challenging, expensive high-field magnets. The data at 4.7 T and 0.0475 T was obtained from different spectrometers with different RF probes. The SNR comparison between the two field strengths accounted for many differences in parameters such as system noise figures and variations in the probe detection coils including Q factors and coil diameters.

  7. Mitigated-force carriage for high magnetic field environments

    Science.gov (United States)

    Ludtka, Gerard M; Ludtka, Gail M; Wilgen, John B; Murphy, Bart L

    2014-05-20

    A carriage for high magnetic field environments includes a first work-piece holding means for holding a first work-piece, the first work-piece holding means being disposed in an operable relationship with a work-piece processing magnet having a magnetic field strength of at least 1 Tesla. The first work-piece holding means is further disposed in operable connection with a second work-piece holding means for holding a second work-piece so that, as the first work-piece is inserted into the magnetic field, the second work-piece is simultaneously withdrawn from the magnetic field, so that an attractive magnetic force imparted on the first work-piece offsets a resistive magnetic force imparted on the second work-piece.

  8. Effects of high solenoidal magnetic fields on rf accelerating cavities

    Directory of Open Access Journals (Sweden)

    A. Moretti

    2005-07-01

    Full Text Available We have measured the effects of high (0–4.5 T magnetic fields on the operating conditions of 805 MHz accelerating cavities, and discovered that the maximum accelerating gradient drops as a function of the axial magnetic field. While the maximum gradient of any cavity is governed by a number of factors including conditioning, surface topology and materials, we argue that J×B forces within the emitters are the mechanism for enhanced breakdown in magnetic fields. The pattern of emitters changes over time and we show an example of a bright emitter which disappears during a breakdown event. We also present unique measurements of the distribution of enhancement factors, β, of secondary emitters produced in breakdown events during conditioning. We believe these secondary emitters can also be breakdown triggers, and the secondary emitter spectrum helps to determine the maximum operating field.

  9. Critical current of a high Tc Josephson grain boundary junction in high magnetic field

    Science.gov (United States)

    Däumling, M.; Sarnelli, E.; Chaudhari, P.; Gupta, A.; Lacey, J.

    1992-09-01

    The critical current (Ic) of YBa2Cu3O7-δ grain boundary Josephson junctions was measured up to magnetic fields of 5 T. Magnetic field history dependent Ic values were observed even after correction for self-field effects stemming from hysteretic shielding currents in the grain adjacent to the boundary. A novel feature observed is an anomalous increase in Ic in high magnetic fields of several Telsa.

  10. Field Investigation of Natural Attenuation of a Petroleum Hydrocarbon Contaminated Aquifer, Gyeonggi Province, Korea

    Science.gov (United States)

    Yang, J.; Lee, K.; Bae, G.

    2004-12-01

    In remediation of a petroleum hydrocarbon contaminated aquifer, natural attenuation may be significant as a remedial alternative. Therefore, natural attenuation should be investigated in the field in order to effectively design and evaluate the remediation strategy at the contaminated site. This study focused on evaluating the natural attenuation for benzene, toluene, ethylbenzene, and xylene (BTEX) at a contaminated site in South Korea. At the study site, the aquifer is composed of a high permeable gravel layer and relatively low permeable sandy-silt layers. Groundwater level vertically fluctuated between 1m and 2m throughout the year (April, 2003~June, 2004) and showed direct response to rainfall events. Chemical analyses of sampled groundwater were performed to investigate the concentrations of various chemical species which are associated with the natural attenuation processes. To evaluate the degree of the biodegradation, the expressed biodegradation capacity (EBC) analysis was done using aerobic respiration, nitrate reduction, manganese reduction, ferric iron reduction, and sulfate reduction as an indicator. High EBC value of sulfate indicate that anaerobic biodegradation by sulfate reduction was a dominant process of mineralization of BTEX at this site. The EBC values decrease sensitively when heavy rainfall occurs due to the dilution and inflow of electron acceptors through a gravel layer. The first-order biodegradation rates of BTEX were estimated by means of the Buscheck and Alcantar method (1995). Results show that the natural attenuation rate of benzene was the highest among the BTEX.

  11. Investigation of capacitance characteristics in metal/high-k ...

    Indian Academy of Sciences (India)

    Keywords. C − V characteristic; high-k dielectric; interface state density; MIS structure; nanotechnology; TCAD simulation. Abstract. Capacitance vs. voltage ( C − V ) curves at AC high frequency of a metal–insulator–semiconductor (MIS) capacitorare investigated in this paper. Bi-dimensional simulations with Silvaco TCAD ...

  12. Investigation of capacitance characteristics in metal/high-k

    Indian Academy of Sciences (India)

    Keywords. C − V characteristic; high-k dielectric; interface state density; MIS structure; nanotechnology; TCAD simulation. Abstract. Capacitance vs. voltage ( C − V ) curves at AC high frequency of a metal–insulator–semiconductor (MIS) capacitorare investigated in this paper. Bi-dimensional simulations with Silvaco TCAD ...

  13. Investigation by perturbative and analytical method of electronic properties of square quantum well under electric field

    Directory of Open Access Journals (Sweden)

    Mustafa Kemal BAHAR

    2010-06-01

    Full Text Available In this study, the effects of applied electric field on the isolated square quantum well was investigated by analytic and perturbative method. The energy eigen values and wave functions in quantum well were found by perturbative method. Later, the electric field effects were investigated by analytic method, the results of perturbative and analytic method were compared. As well as both of results fit with each other, it was observed that externally applied electric field changed importantly electronic properties of the system.

  14. Question Paper Investigation about Health Behavior of High School Students

    OpenAIRE

    丸岡, 里香

    2006-01-01

    This investigation did what I made clear about the present conditions of a well action about health of subjectivity of a high school student, living habit, eating habits with a purpose. It is 1〜3 grader man and woman who attend school to the public high school of the coeducation in Hokkaido, and is the student who was able to get consent to investigation cooperation. As a result, about 90% things which thought that a high school student was well as oneself were, but about 90% things which fel...

  15. High mobility polymer gated organic field effect transistor using zinc ...

    Indian Academy of Sciences (India)

    Mater. Sci., Vol. 37, No. 1, February 2014, pp. 95–99. c Indian Academy of Sciences. High mobility polymer gated organic field effect transistor using zinc phthalocyanine. K R RAJESH. ∗. , V KANNAN, M R KIM, Y S CHAE and J K RHEE. Millimeter- Wave Innovation Technology Research Centre (MINT), Dongguk University,.

  16. Free-field calibration of measurement microphones at high frequencies

    DEFF Research Database (Denmark)

    Barrera Figueroa, Salvador; Rasmussen, Knud; Torras Rosell, Antoni

    2011-01-01

    Measurement microphones are typically calibrated in a free field at frequencies up to 50 kHz. This is a sufficiently high frequency for the most of sound measurement applications related with noise assessment. However, other applications such as assessment of the noise emitted by ultrasound clean...

  17. Field testing of high-efficiency supermarket refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D. (Foster-Miller, Inc., Waltham, MA (United States))

    1992-12-01

    The Electric Power Research Institute (EPRI) has undertaken a field test to quantify the performance of high-efficiency supermarket refrigeration. The initial work on this project was presented in EPRI report CU-6268 Supermarket Refrigeration Modeling and Field Demonstration.'' The information given here was generated through continued testing at the field test site. The field test was conducted at a supermarket owned by Safeway Stores, Inc., that was located in Menlo Park, CA. Testing was performed with the existing conventional refrigeration system and a high-efficiency multiplex refrigeration system that was installed for these tests. The results of the testing showed that the high-efficiency multiplex system reduced refrigeration energy consumption by 23.9% and peak electric demand for refrigeration by 30.0%. Analyses of these savings showed that the largest portion was due to the use of high-efficiency compressors (29.5% of total saving). Floating head pressure control, ambient and mechanical subcooling, compressor multiplexing and hot gas defrost accounted for 50% of total savings. The remainder of the savings (20.5%) were attributed to the use of an evaporative condenser. Tests were also conducted with several retrofit technologies. The most promising results were obtained with external liquid-suction heat exchangers installed at the outlets of the display cases. Favorable paybacks were calculated for these exchangers when they were used with very low and low temperature refrigeration.

  18. High intensity electromagnetic field gerenation using a transportable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2008-01-01

    A reverberation chamber can create very high field strength with moderate input power. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. A transportable reverberation chamber with vibrating walls will be presented. Inside this Vibrating Intrinsic

  19. High mobility polymer gated organic field effect transistor using zinc ...

    Indian Academy of Sciences (India)

    Organic semiconductor; field effect transistor; phthalocyanine; high mobility. Abstract. Organic thin film transistors were fabricated using evaporated zinc phthalocyanine as the active layer. Parylene film prepared by chemical vapour deposition was used as the organic gate insulator. The annealing of the samples was ...

  20. Multibeam synthesis of high-power subcycle field waveforms

    Science.gov (United States)

    Serebryannikov, E. E.; Panchenko, V. Ya.; Zheltikov, A. M.

    2017-09-01

    We identify physical scenarios whereby high-peak-power subcycle attosecond field waveforms can be synthesized by coherently combining a multibeam high-order harmonic output generated by a laser driver consisting of a pair of few-cycle pulses with different carrier frequencies. With the relative amplitudes, phases, and group delays of these driver pulses carefully adjusted in each of the driver beams toward confining the recollisions of highest-ponderomotive-energy electrons to an extremely short time gate within a fraction of the driver field cycle, the phase-matched multibeam high-harmonic output can be tailored to yield an intense isolated subgigawatt sub-10-attosecond field waveform. As a general tendency, propagation effects are shown to limit the minimum pulse width of the multibeam high-harmonic output. Still, with appropriate optimization of the gas pressure and the beam geometry, ≈10 -as field waveforms can be synthesized at the expense of one to two orders of magnitude of the output radiation energy.

  1. Survey of high field superconducting material for accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scahlan, R.; Greene, A.F.; Suenaga, M.

    1986-05-01

    The high field superconductors which could be used in accelerator dipole magnets are surveyed, ranking these candidates with respect to ease of fabrication and cost as well as superconducting properties. Emphasis is on Nb/sub 3/Sn and NbTi. 27 refs., 2 figs. (LEW)

  2. Anomalous electric field changes and high flash rate beneath a ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 119; Issue 5. Anomalous electric field changes and high flash rate beneath a thunderstorm in northeast India ... Further,all electric field changes after a lightning discharge indicates the presence of strong Lower Positive Charge Centers (LPCC)in the active and ...

  3. Comparison of high-field (1.5 T) and low-field (0.2 T) MR imaging for the reliability of meniscal diagnosis

    International Nuclear Information System (INIS)

    Rand, T.; Imhof, H.; Breitenseher, M.; Happel, B.; Trattnig, S.; Turetschek, K.; Schneider, B.

    1997-01-01

    The aim of this study was to evaluate the reliability of a low field strength MRI unit (0.2 T; Esaote, Biomedica) and a high field strength MRI unit (1.5 T; Siemens) in detecting meniscal lesions. Twenty patients were investigated on a 0.2-T low-field MRI unit and a 1.5-T high-field MRI unit for meniscal lesions. Evaluation was performed of four meniscal compartments (anterior and posterior medial and lateral meniscus), for a total of 80 observations. The reliability of diagnosis was ranked qualitatively on a three-point scale. Investigations of the high-field MRI unit revealed a meniscal tear in 6 patients and ruled out a tear in 15 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 58 observations and with moderate confidence in 22 observations. Investigations of the low-field MRI unit revealed a meniscal tear in 5 patients and ruled out tears in 14 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 39 observations, with moderate confidence in 38 observations, and with low confidence in 3 observations. The diagnosis in high- and low-field images was identical in 98.7% of cases; in one patient observations from the high-field unit changed the therapeutic management. (orig.) [de

  4. Generation and measurement of pulsed high magnetic field

    CERN Document Server

    Jana, S

    2000-01-01

    Pulsed magnetic field has been generated by discharging a capacitor bank through a 5-layer air-core solenoid. The strength of the magnetic field at its peak has been measured using the voltage induced in various pick-up coils, and also from the Zeeman splitting of an ion having a known g value. Synchronizing a xenon flash at the peak of the magnetic field, this lab-made instrument has been made well suited to study the Zeeman effect, etc. at a temperature of 25 K. As an application of this setup, we have investigated the Zeeman splitting of the sup 4 I sub 9 sub / sub 2-> sup 4 G sub 5 sub / sub 2 transition of the Nd sup 3 sup + -doped CsCdCl sub 3 crystal at 7.8 T, and determined the splitting factors.

  5. Medical investigation on the effects of radioactivity in the field of petrochemistry

    International Nuclear Information System (INIS)

    Li Xinluan; Gao Min; Shao Hua; Liu Wei; Li Qingjie; Hou Dianjun; Qiao Jianwei; Lin Haiqun; Shang Ximei

    2005-01-01

    Objective: To investigate the health condition of the people who work in the petrochemical field and to provide the basis for the policy-making of control and survey of the radiology disease. Methods: To measure the volume of radioactivity individual in the environment of the people who work in the field of petrochemistry and consequently to cheek and analysize the changes in physical and biochemistry. Results: The annual volume of radioactivity exposure individual is 5.667 mSv·a -1 , >50 mSv·a -1 20. Consequently, this volume can induce many abnormalities in human body. Compare to the control group, the abnormalities include high blood pressure of abnormal EKG, eye disease, low white blood ceels, the changed rate of CD 4 /CD 8 , distortion of DNA and appearances of higher micronucleus. Conclusion: Long time exposure to low volume of radiation will cause some of the abnormalities to humanbody. Therefore, the health protection measures should be strengthened. (authors)

  6. An investigation into the vector ellipticity of extremely low frequency magnetic fields from appliances in UK homes

    Science.gov (United States)

    Ainsbury, Elizabeth A.; Conein, Emma; Henshaw, Denis L.

    2005-07-01

    Elliptically polarized magnetic fields induce higher currents in the body compared with their plane polarized counterparts. This investigation examines the degree of vector ellipticity of extremely low frequency magnetic fields (ELF-MFs) in the home, with regard to the adverse health effects reportedly associated with ELF-MFs, for instance childhood leukaemia. Tri-axial measurements of the magnitude and phase of the 0-3000 Hz magnetic fields, produced by 226 domestic mains-fed appliances of 32 different types, were carried out in 16 homes in Worcestershire in the summer of 2004. Magnetic field strengths were low, with average (RMS) values of 0.03 ± 0.02 µT across all residences. In contrast, background field ellipticities were high, on average 47 ± 11%. Microwave and electric ovens produced the highest ellipticities: mean respective values of 21 ± 21% and 21 ± 17% were observed 20 cm away from these appliances. There was a negative correlation between field strength and field polarization, which we attribute to the higher relative field contribution close to each individual (single-phase) appliance. The measurements demonstrate that domestic magnetic fields are extremely complex and cannot simply be characterized by traditional measurements such as time-weighted average or peak exposure levels. We conclude that ellipticity should become a relevant metric for future epidemiological studies of health and ELF-MF exposure. This work is supported by the charity CHILDREN with LEUKAEMIA, registered charity number 298405.

  7. Experimental investigation on the repetitively nanosecond pulsed dielectric barrier discharge with the parallel magnetic field

    Science.gov (United States)

    Liu, Yidi; Yan, Huijie; Guo, Hongfei; Fan, Zhihui; Wang, Yuying; Ren, Chunsheng

    2018-02-01

    The effects of a parallel magnetic field on the unipolar positive nanosecond pulsed dielectric barrier discharge are experimentally investigated through electrical and spectral measurements. The discharge is produced between two parallel-plate electrodes in the ambient air with a parallel magnetic field of 1.4 T. Experimental results show that both the discharge intensity and uniformity are improved in the discharge with the parallel magnetic field. The intensity ratio of the spectrum at 371.1 nm and 380.5 nm, which describes the average electron density, is increased by the parallel magnetic field. Meanwhile, the intensity ratio of the spectrum at 391.4 nm and 337.1 nm, which describes the electron temperature, is also increased. It is speculated that both the average electron density and the electron temperature are increased by the parallel magnetic field. The aforementioned phenomena have been explained by the confinement effect of the parallel magnetic field on the electrons.

  8. A statistical study of high-altitude electric fields measured on the Viking satellite

    International Nuclear Information System (INIS)

    Lindqvist, P.A.; Marklund, G.T.

    1990-01-01

    Characteristics of high-altitude data from the Viking electric field instrument are presented in a statistical study based on 109 Viking orbits. The study is focused in particular on the signatures of and relationships between various parameters measured by the electric field instrument, such as the parallel and transverse (to B) components of the electric field instrument, such as electric field variability. A major goal of the Viking mission was to investigate the occurrence and properties of parallel electric fields and their role in the auroral acceleration process. The results in this paper on the altitude distribution of the electric field variability confirm earlier findings on the distribution of small-scale electric fields and indicate the presence of parallel fields up to about 11,000 km altitude. The directly measured parallel electric field is also investigated in some detail. It is in general directed upward with an average value of 1 mV/m, but depends on, for example, altitude and plasma density. Possible sources of error in the measurement of the parallel field are also considered and accounted for

  9. The forced flow high field test facility SULTAN

    International Nuclear Information System (INIS)

    Horvath, I.; Vecsey, G.; Weymuth, P.

    1984-01-01

    The construction of the 8 Tesla, 1 m bore Test Facility SULTAN - I, a common action of ENEA (I-Frascati), ECN (NL-Petten) and SIN (CH-Villigen), is completed. Results on assembly, cooldown and the first operation of the whole system are presented. The SULTAN facility provides a wide range of capability of parameter variations (field, current, cooling) for the investigation of steady state performance and stability of technical superconductors unders nominal and limiting conditions

  10. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Field Investigation report

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

  11. Investigation of Combined High-Frequency and Arc Discharges

    International Nuclear Information System (INIS)

    Taran, V.S.; Nezovibatko, Yu.N.; Marinin, V.G.; Shvets, O.M.; Ridozub, V.N.; Gasilin, V.V.

    2001-01-01

    In this paper we analyze experiment with arc and high-frequency (HF) plasma sources carried out in modified devise of the ''Bulat'' type. The HF-sources and combined discharges have attracted considerable attention for surface cleaning and coating. The utilization of such discharges allows decreasing droplet fraction formation and providing better adhesion and microhardness values. The existence of HF-field in plasma allows obtaining either conductive or dielectric coatings and they can be deposited on any substrates. (author)

  12. Transport of Indirect Excitons in High Magnetic Fields

    Science.gov (United States)

    Dorow, C. J.; Kuznetsova, Y. Y.; Calman, E. V.; Butov, L. V.; Wilkes, J.; Campman, K. L.; Gossard, A. C.

    Spatially- and spectrally-resolved photoluminescence measurements of indirect excitons in high magnetic fields are presented. The high magnetic field regime for excitons is realized when the cyclotron splitting compares to the exciton binding energy. Due to small mass and binding energy, the high magnetic field regime for excitons is achievable in lab, requiring a few Tesla. Long indirect exciton lifetimes allow large exciton transport distances before recombination, giving an opportunity to study transport and relaxation kinetics of indirect magnetoexcitons via optical imaging. Indirect excitons in several Landau level states are realized. 0e -0h indirect magnetoexcitons (formed from electrons and holes at zeroth Landau levels) travel over large distances and form an emission ring around the excitation spot. In contrast, the 1e -1h and 2e -2h states do not exhibit long transport distances, and the spatial profiles of the emission closely follow the laser excitation. The 0e -0h indirect magnetoexciton transport distance reduces with increasing magnetic field. Accompanying theoretical work explains these effects in terms of magnetoexciton energy relaxation and effective mass enhancement. Supported by NSF Grant No. 1407277. J.W. was supported by the EPSRC (Grant EP/L022990/1). C.J.D. was supported by the NSF Graduate Research Fellowship Program under Grant No. DGE-1144086.

  13. High critical magnetic field superconductor La3S4

    International Nuclear Information System (INIS)

    Westerholt, K.; Bach, H.; Wendemuth, R.; Methfessel, S.

    1979-01-01

    A report is presented on electrical conductivity, specific heat and magnetization measurements on La 3 S 4 single crystals. The results show that La 3 S 4 is a strong coupling superconductor with a BCS coherence length of 132 A. This extremely low value makes La 3 S 4 an intrinsic high critical magnetic field superconductor with a Landau-Ginsburg parameter of 20. For the temperature gradient of the upper critical magnetic field at the transition temperature values are found up to 35 kG/K. (author)

  14. Transport of indirect excitons in high magnetic fields

    Science.gov (United States)

    Kuznetsova, Y. Y.; Dorow, C. J.; Calman, E. V.; Butov, L. V.; Wilkes, J.; Muljarov, E. A.; Campman, K. L.; Gossard, A. C.

    2017-03-01

    We present spatially and spectrally resolved photoluminescence measurements of indirect excitons in high magnetic fields. Long indirect exciton lifetimes give the opportunity to measure magnetoexciton transport by optical imaging. Indirect excitons formed from electrons and holes at zeroth Landau levels (0e-0h indirect magnetoexcitons) travel over large distances and form a ring emission pattern around the excitation spot. In contrast, the spatial profiles of 1e-1h and 2e-2h indirect magnetoexciton emission closely follow the laser excitation profile. The 0e-0h indirect magnetoexciton transport distance reduces with increasing magnetic field. These effects are explained in terms of magnetoexciton energy relaxation and effective mass enhancement.

  15. High-field EPR spectroscopy of thermal donors in silicon

    DEFF Research Database (Denmark)

    Dirksen, R.; Rasmussen, F.B.; Gregorkiewicz, T.

    1997-01-01

    Thermal donors generated in p-type boron-doped Czochralski-grown silicon by a 450 degrees C heat treatment have been studied by high-field magnetic resonance spectroscopy. In the experiments conducted at a microwave frequency of 140 GHz and in a magnetic field of approximately 5 T four individual...... thermal donors species could be resolved. These were observed in their singly ionized TD+ charge state. For the first time in the four decades of thermal donor research the g tensor values for specific members of the Si-NL8 family are given. Also the symmetry of the observed species is discussed....

  16. High field superconductor development and understanding project, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David C.; Lee, Peter J.

    2009-07-15

    Over 25 years the Applied Superconductivity Center at the University of Wisconsin-Madison provided a vital technical resource to the High Energy Physics community covering development in superconducting strand for HEP accelerator magnet development. In particular the work of the group has been to develop the next generation of high field superconductors for high field application. Grad students Mike Naus, Chad Fischer, Arno Godeke and Matt Jewell improved our understanding of the microstructure and microchemistry of Nb3Sn and their impact on the physical and mechanical properties. The success of this work has led to the continued funding of this work at the ASC after it moved to the NHMFL and also to direct funding from BNL for some aspects of Nb3Sn cable evaluation.

  17. Investigation in Query System Framework for High Energy Physics

    CERN Document Server

    Jatuphattharachat, Thanat

    2017-01-01

    We summarize an investigation in query system framework for HEP (High Energy Physics). Our work was an investigation on distributed server part of Femtocode, which is a query language that provides the ability for physicists to make plots and other aggregations in real-time. To make the system more robust and capable of processing large amount of data quickly, it is necessary to deploy the system on a redundant and distributed computing cluster. This project aims to investigate third party coordination and resource management frameworks which fit into the design of real-time distributed query system. Zookeeper, Mesos and Marathon are the main frameworks for this investigation. The results indicate that Zookeeper is good for job coordinator and job tracking as it provides robust, fast, simple and transparent read and write process for all connecting client across distributed Zookeeper server. Furthermore, it also supports high availability access and consistency guarantee within specific time bound.

  18. Wave propagation downstream of a high power helicon in a dipolelike magnetic field

    International Nuclear Information System (INIS)

    Prager, James; Winglee, Robert; Roberson, B. Race; Ziemba, Timothy

    2010-01-01

    The wave propagating downstream of a high power helicon source in a diverging magnetic field was investigated experimentally. The magnetic field of the wave has been measured both axially and radially. The three-dimensional structure of the propagating wave is observed and its wavelength and phase velocity are determined. The measurements are compared to predictions from helicon theory and that of a freely propagating whistler wave. The implications of this work on the helicon as a thruster are also discussed.

  19. Nonlinear Optimization of CLIC DRS New Design with Variable Bends and High Field Wigglers

    CERN Document Server

    Ghasem, H.; Alabau-Gonzalvo, J.; Papadopoulou, S.; Papaphilippou, Y.

    2016-01-01

    The new design of CLIC damping rings is based on longitudinal variable bends and high field superconducting wiggler magnets. It provides an ultra-low horizontal normalised emittance of 412 nm-rad at 2.86 GeV. In this paper, nonlinear beam dynamics of the new design of the damping ring (DR) with trapezium field profile bending magnets have been investigated in detail. Effects of the misalignment errors have been studied in the closed orbit and dynamic aperture.

  20. High sensitive LPFG magnetic field sensor based on dual-peak resonance

    Science.gov (United States)

    Gu, Zhengtian; Ling, Qiang; Lan, Jinlong; Gao, Kan

    2017-11-01

    A high sensitivity magnetic field sensor based on magnetic-fluid-clad LPFG structure with dual peak resonance is presented and experimentally investigated. Based on coupled mode theory, the sensing principle of this sensor is originated from the sensibility of the dual peak based LPFG to the environment refractive index. In experiment, a dual peak interval change was available to 38 nm with a magnetic field strength varying from 0 to 12 mT when the temperature was 17.3 °C, and the dual peak interval displays a cubic polynomial dependence with the magnetic field strength at the low field regime. The sensitivity of this sensor to the magnetic field can be available to 4.08 nm/mT, and it is one order and two orders of magnitude higher than that of the sensors based on MSM and SMS fiber structure, respectively. The novel sensor has many advantages of simple technology, structure stability and high sensitivity.

  1. Ultra-High Field Magnets for X-Ray and Neutron Scattering using High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Winn, Barry L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Broholm, C. [Johns Hopkins Univ., Baltimore, MD (United States); Bird, M. [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Breneman, Bruce C. [General Atomics, San Diego, CA (United States); Coffey, Michael [Cryomagnetics, Oak Ridge, TN (United States); Cutler, Roy I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duckworth, Robert C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Erwin, R. [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Hahn, Seungyong [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Hernandez, Yamali [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Herwig, Kenneth W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holland, Leo D. [General Atomics, San Diego, CA (United States); Lonergan, Kevin M. [Oxford Instruments, Abingdon (United Kingdom); Melhem, Ziad [Oxford Instruments, Abingdon (United Kingdom); Minter, Stephen J. [Cryomagnetics, Oak Ridge, TN (United States); Nelson, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Paranthaman, M. Parans [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pierce, Josh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ruff, Jacob [Cornell Univ., Ithaca, NY (United States); Shen, Tengming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherline, Todd E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smeibidl, Peter G. [Helmholtz-Zentrum Berlin (HZB), (Germany); Tennant, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); van der Laan, Danko [Advanced Conductor Technologies, LLC, Boulder, CO (United States); Wahle, Robert J. [Helmholtz-Zentrum Berlin (HZB), (Germany); Zhang, Yifei [SuperPower, Inc., Schenectady, NY (United States)

    2017-01-01

    X-ray and neutron scattering techniques are capable of acquiring information about the structure and dynamics of quantum matter. However, the high-field magnet systems currently available at x-ray and neutron scattering facilities in the United States are limited to fields of 16 tesla (T) at maximum, which precludes applications that require and/or study ultra-high field states of matter. This gap in capability—and the need to address it—is a central conclusion of the 2005 National Academy of Sciences report by the Committee on Opportunities in High Magnetic Field Science. To address this gap, we propose a magnet development program that would more than double the field range accessible to scattering experiments. With the development and use of new ultra-high field–magnets, the program would bring into view new worlds of quantum matter with profound impacts on our understanding of advanced electronic materials.

  2. Rf Gun with High-Current Density Field Emission Cathode

    International Nuclear Information System (INIS)

    Jay L. Hirshfield

    2005-01-01

    High current-density field emission from an array of carbon nanotubes, with field-emission-transistor control, and with secondary electron channel multiplication in a ceramic facing structure, have been combined in a cold cathode for rf guns and diode guns. Electrodynamic and space-charge flow simulations were conducted to specify the cathode configuration and range of emission current density from the field emission cold cathode. Design of this cathode has been made for installation and testing in an existing S-band 2-1/2 cell rf gun. With emission control and modulation, and with current density in the range of 0.1-1 kA/cm2, this cathode could provide performance and long-life not enjoyed by other currently-available cathodes

  3. Control and data acquisition systems for high field superconducting wigglers

    CERN Document Server

    Batrakov, A; Karpov, G; Kozak, V; Kuzin, M; Kuper, E; Mamkin, V; Mezentsev, N A; Repkov, V V; Selivanov, A; Shkaruba, V A

    2001-01-01

    This paper describes the control and DAQ system of superconducting wigglers with magnetic field range up to 10.3 T. The first version of the system controls a 7 T superconducting wiggler prepared for installation at Bessy-II (Germany). The second one controls a 10 T wiggler which is under testing now at the SPring-8 site (Japan). Both systems are based on VME apparatus. The set of specialized VME modules is elaborated to arrange wiggler power supply control, full time wiggler monitoring, and magnetic field high accuracy measurement and field stabilization. The software for the control of the wigglers is written in C language for VxWorks operation system for a Motorola-162 VME controller. The task initialization, stops and acquisition of the data can be done from the nearest personal computer (FTP host for VME), or from the remote system as well.

  4. Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

    DEFF Research Database (Denmark)

    Orlof, A.; Shylau, Artsem; Zozoulenko, I. V.

    2015-01-01

    We study the effect of electron-electron interaction in graphene quantum dots defined by an external electrostatic potential and a high magnetic field. To account for the electron-electron interaction, we use the Thomas-Fermi approximation and find that electron screening causes the formation...... of compressible strips in the potential profile and the electron density. We numerically solve the Dirac equations describing the electron dynamics in quantum dots, and we demonstrate that compressible strips lead to the appearance of plateaus in the electron energies as a function of the magnetic field. Finally...

  5. Limited field investigation report for the 100-KR-4 Operable Unit

    International Nuclear Information System (INIS)

    1994-07-01

    This limited field investigation (LFI) was conducted to optimize the use of interim remedial measures (IRM) for expediting clean up while maintaining a technically sound and cost-effective program. The 100-KR-4 Operable Unit is one of four operable units associated with the 100 K Area. Operable units KR-1, KR-2 and KR-3 address contaminant sources while 100-KR-4 addresses contamination present in the underlying groundwater. The IRM decision process for groundwater operable units is based on three aspects: (1) Is the concentration greater than Hanford background? (2) Does the concentration present a medium or high human-health risk? (3) Does the concentration exceed an ecologically based applicable, relevant and appropriate requirements (ARAR) or present an environmental hazard quotient > I? The primary methods of investigation used during this LFI were the installation of monitoring wells and sampling of groundwater. The samples collected from the groundwater and soils were submitted for laboratory analysis. Boreholes were surveyed for radiological contamination using downhole geophysical techniques to further delineate the location and degree of contamination. All soil samples were screened to ascertain the presence of volatile organic compounds and radionuclides. Analytical data were subjected to validation; all first round and a minimum of 10% of subsequent round data were validated

  6. Report on health and environmental effects of electromagnetic fields produced by high and very high voltage lines

    International Nuclear Information System (INIS)

    2010-01-01

    In its first part, this report presents some characteristics and properties of electric, magnetic and electromagnetic fields, indicates which are the artificial sources of exposure to very low frequency electromagnetic fields, and gives an overview of some investigations and researches on the exposure to magnetic fields. The second part contains a description of the French high and very high voltage network, its role and development. It also discusses the possibility of burying these lines, and outlines the importance of citizen participation. The third part deals with the potential impacts on health; it comments the results of international studies, discusses the problem of electro-hypersensitivity (EHS) and the relationship between electric and magnetic fields and infantile leukaemia. The fourth part deals with the potential impacts on the environment, animals, agriculture

  7. High-energy behavior of field-strength interactions

    International Nuclear Information System (INIS)

    Levin, D.N.

    1976-01-01

    It is known that spontaneously broken gauge theories are the only renormalizable theories of massive spin-one particles with mass dimension less than or equal to 4. This paper describes a search for renormalizable interactions with higher mass dimension. Specifically, we examine the high-energy behavior of a class of models which involve field-strength interactions. Power counting shows that the high-energy behavior of these models is no worse than the naively estimated high-energy behavior of a gauge theory in the U gauge. Therefore, there may be a ''soft'' symmetry-breaking mechanism (for instance, a soft divergence of an antisymmetric tensor current) which enforces renormalizable high-energy behavior in the same way that spontaneously broken gauge invariance guarantees the renormalizability of gauge theories. This hope is supported by the existence of ''gauge theories'' of strings, which describe analogous interactions of strings and field strengths. Unfortunately, this idea is tarnished by explicit calculations in which renormalizability is imposed in the form of unitarity bounds. These unitarity bounds imply that all possible field-strength couplings must be zero and that the remaining interactions describe a spontaneously broken gauge theory. Thus this result supports an earlier conjecture that gauge theories are the only renormalizable theories of massive vector bosons

  8. Structural Controls on Groundwater Flow in Basement Terrains: Geophysical, Remote Sensing, and Field Investigations in Sinai

    KAUST Repository

    Mohamed, Lamees

    2015-07-09

    An integrated [very low frequency (VLF) electromagnetic, magnetic, remote sensing, field, and geographic information system (GIS)] study was conducted over the basement complex in southern Sinai (Feiran watershed) for a better understanding of the structural controls on the groundwater flow. The increase in satellite-based radar backscattering values following a large precipitation event (34 mm on 17–18 January 2010) was used to identify water-bearing features, here interpreted as preferred pathways for surface water infiltration. Findings include: (1) spatial analysis in a GIS environment revealed that the distribution of the water-bearing features (conductive features) corresponds to that of fractures, faults, shear zones, dike swarms, and wadi networks; (2) using VLF (43 profiles), magnetic (7 profiles) techniques, and field observations, the majority (85 %) of the investigated conductive features were determined to be preferred pathways for groundwater flow; (3) northwest–southeast- to north–south-trending conductive features that intersect the groundwater flow (southeast to northwest) at low angles capture groundwater flow, whereas northeast–southwest to east–west features that intersect the flow at high angles impound groundwater upstream and could provide potential productive well locations; and (4) similar findings are observed in central Sinai: east–west-trending dextral shear zones (Themed and Sinai Hinge Belt) impede south to north groundwater flow as evidenced by the significant drop in hydraulic head (from 467 to 248 m above mean sea level) across shear zones and by reorientation of regional flow (south–north to southwest–northeast). The adopted integrated methodologies could be readily applied to similar highly fractured basement arid terrains elsewhere. © 2015 Springer Science+Business Media Dordrecht

  9. High energy heavy ion collisions from the view point of the 'strong field physics'

    International Nuclear Information System (INIS)

    Itakura, Kazunori

    2012-01-01

    In the high energy heavy ion collisions at the facilities like RHIC and LHC, two strongest fields in the present universe are generated. First of all, a very strong electromagnetic field is generated, though its duration is very short due to the very high speed collisions of nuclei and the large electric charges. On the other hand, the nuclei are described as the high density saturation gluon state just before the moment of the collision and the high density gluon is released by the collision. A very strong color electromagnetic field is generated. The color glass condensate (CGC) is a reasonable picture. In this text, dynamics of the GLASMA (Glass + plasma), the new physics brought about by those 'strong fields', are introduced and are explained how the yet unsolved problems of the heavy ion collisions are going to be investigated on the new view point. The mechanism of the apparitions of the strong electromagnetic field and the strong color electromagnetic field are explained at first. The heavy ion collisions can be described as the process CGC to develop into QGP. As the phenomena under the strong electromagnetic field and the heavy ion collisions, their synchrotron radiations, the photon birefringence, the photon decay, the splitting of photons and the chiral phase transitions under high field are picked up. Concerning the strong color electromagnetic field dynamics and the heavy ion collisions, the plasma flux tube dynamics, the color magnetic flux tube, the color electric flux tube and the coexisting case of the color electric field and magnetic field are presented. (S. Funahashi)

  10. Comparative investigation of three dose rate meters for their viability in pulsed radiation fields

    International Nuclear Information System (INIS)

    Gotz, M; Karsch, L; Pawelke, J

    2015-01-01

    Pulsed radiation fields, characterized by microsecond pulse duration and correspondingly high pulse dose rates, are increasingly used in therapeutic, diagnostic and research applications. Yet, dose rate meters which are used to monitor radiation protection areas or to inspect radiation shielding are mostly designed, characterized and tested for continuous fields and show severe deficiencies in highly pulsed fields. Despite general awareness of the problem, knowledge of the specific limitations of individual instruments is very limited, complicating reliable measurements. We present here the results of testing three commercial dose rate meters, the RamION ionization chamber, the LB 1236-H proportional counter and the 6150AD-b scintillation counter, for their response in pulsed radiation fields of varied pulse dose and duration. Of these three the RamION proved reliable, operating in a pulsed radiation field within its specifications, while the other two instruments were only able to measure very limited pulse doses and pulse dose rates reliably. (paper)

  11. Traversing field of view and AR-PIV for mid-field wake vortex investigation in a towing tank

    Science.gov (United States)

    Scarano, F.; van Wijk, C.; Veldhuis, L. L. M.

    2002-08-01

    Wake vortex flow experiments are performed in a water tank where a 1:48 scaled model of a large transport aircraft A340-300 is towed at the speed of 3 and 5 ms-1 with values of the angle of attack α={2°, 4°, 8°}. Particle image velocimetry (PIV) measurements are performed in a plane perpendicular to the towing direction describing the streamwise component of the wake vorticity. The instantaneous field of view (I-FOV) is traversed vertically with an underwater moving-camera device tracking the vortex core during the downward motion. An adaptive resolution (AR) image-processing technique is introduced that enhances the PIV interrogation in terms of spatial resolution and accuracy. The main objectives of the investigation are to demonstrate the applicability of PIV diagnostics in wake vortex research with towing-tank facilities. The specific implementation of the traversing field-of-view (T-FOV) technique and the AR image processing are driven by the need to characterize the vortex wake global properties as well as the vortex decay phenomenon in the mid- and far-field. Relevant aerodynamic information is obtained in the mid-field where the time evolution of the vortex structure (core radius and tangential velocity) and of the overall vortex wake (vortex trajectory, descent velocity, circulation) are discussed.

  12. Numerical investigation on splitting of ferrofluid microdroplets in T-junctions using an asymmetric magnetic field with proposed correlation

    Science.gov (United States)

    Aboutalebi, Mohammad; Bijarchi, Mohamad Ali; Shafii, Mohammad Behshad; Kazemzadeh Hannani, Siamak

    2018-02-01

    The studies surrounding the concept of microdroplets have seen a dramatic increase in recent years. Microdroplets have applications in different fields such as chemical synthesis, biology, separation processes and micro-pumps. This study numerically investigates the effect of different parameters such as Capillary number, Length of droplets, and Magnetic Bond number on the splitting process of ferrofluid microdroplets in symmetric T-junctions using an asymmetric magnetic field. The use of said field that is applied asymmetrically to the T-junction center helps us control the splitting of ferrofluid microdroplets. During the process of numerical simulation, a magnetic field with various strengths from a dipole located at a constant distance from the center of the T-junction was applied. The main advantage of this design is its control over the splitting ratio of daughter droplets and reaching various microdroplet sizes in a T-junction by adjusting the magnetic field strength. The results showed that by increasing the strength of the magnetic field, the possibility of asymmetric splitting of microdroplets increases in a way that for high values of field strength, high splitting ratios can be reached. Also, by using the obtained results at various Magnetic Bond numbers and performing curve fitting, a correlation is derived that can be used to accurately predict the borderline between splitting and non-splitting zones of microdroplets flow in micro T-junctions.

  13. Wide-field high-performance geosynchronous imaging

    International Nuclear Information System (INIS)

    Wood, H. John; Jenstrom, Del; Wilson, Mark; Hinkal, Sanford; Kirchman, Frank

    1998-01-01

    The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches. The imager design started with a look at first principles: what is the most efficient way to image the Earth in those numerous spectral bands of interest to MTPE scientists and NOAA weather forecasters. Optical design trades included rotating filter wheels and dispersive grating instruments. The design converged on a bandpass filter instrument using four focal planes to cover the spectral range 0.45 to 13.0 micrometers. The first imager design uses a small agile spacecraft supporting an afocal optical telescope. Dichroic beamsplitters feed refractive objectives to four focal planes. The detectors are a series of long linear and rectangular arrays which are scanned in a raster fashion over the 17 degree Earth image. The use of the spacecraft attitude control system to raster the imager field-of-view (FOV) back and forth over the Earth eliminates the need for a scan mirror. However, the price paid is significant energy and time required to reverse the spacecraft slew motions at the end of each scan line. Hence, it is desired to minimize the number of scan lines needed to cover the full Earth disk. This desire, coupled with the ground

  14. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 3: Ecological risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hlohowskyj, I.; Hayse, J.; Kuperman, R.; Van Lonkhuyzen, R.

    2000-02-25

    The Environmental Management Division of the U.S. Army Aberdeen Proving Ground (APG), Maryland, is conducting a remedial investigation (RI) and feasibility study (FS) of the J-Field area at APG, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended. As part of that activity, Argonne National Laboratory (ANL) conducted an ecological risk assessment (ERA) of the J-Field site. This report presents the results of that assessment.

  15. Investigations of scattering and field enhancement effects in retardation-based plasmonic nanoantennas

    DEFF Research Database (Denmark)

    Nielsen, M. G.; Pors, A.; Nielsen, Rasmus Bundgaard

    2010-01-01

    Modifications in scattering strength of and local field enhancement by retardation-based plasmonic nanoantennas when being transformed from straight nanorods to split-rings are investigated. The scattering properties are monitored by linear reflection and extinction spectroscopy whereas local field......, a feature that we attribute to the decrease in the nanoantenna electric-dipole response in tact with its bending. The experimental observations are corroborated with numerical simulations using the finite-element method....

  16. Remedial investigation report for J-Field, Aberdeen Proving Ground, Maryland. Volume 3: Ecological risk assessment

    International Nuclear Information System (INIS)

    Hlohowskyj, I.; Hayse, J.; Kuperman, R.; Van Lonkhuyzen, R.

    2000-01-01

    The Environmental Management Division of the U.S. Army Aberdeen Proving Ground (APG), Maryland, is conducting a remedial investigation (RI) and feasibility study (FS) of the J-Field area at APG, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended. As part of that activity, Argonne National Laboratory (ANL) conducted an ecological risk assessment (ERA) of the J-Field site. This report presents the results of that assessment

  17. Experimental investigation of local properties and statistics of optical vortices in random wave fields

    DEFF Research Database (Denmark)

    Wang, W.; Hanson, Steen Grüner; Miyamoto, Y.

    2005-01-01

    We present the first direct experimental evidence of the local properties of optical vortices in a random laser speckle field. We have observed the Berry anisotropy ellipse describing the anisotropic squeezing of phase lines close to vortex cores and quantitatively verified the Dennis angular mom...... momentum rule for its phase. Some statistics associated with vortices, such as density, anisotropy ellipse eccentricity, and its relation to zero crossings of real and imaginary parts of the random field, are also investigated by experiments....

  18. High-speed photography application to pulsed hot plasma investigation

    International Nuclear Information System (INIS)

    Borov'etskij, M.; Koz'yarkevich, V.; Skrzhechanovskij, V.; Socha, R.

    1986-01-01

    Plasma focus is investigated using an electron-optical chamber for high-speed photography (KSK-1). Experimental devices for studying dynamics and structure of a plasma layer in the chosen interval, recording plasma spectra with time resolution as well as for studying the dynamics and structure of a plasma layer by Schlieren- and shadow methods are briefly described. Experimental results are presented

  19. An Investigation into Physics Teaching in Senior High Schools

    Science.gov (United States)

    Buabeng, Isaac; Ossei-Anto, Theophilus Aquinas; Ampiah, Joseph Ghartey

    2014-01-01

    This study sought to examine the activities that go on in physics classrooms in Senior High Schools in Ghana. Specifically, the study sought to investigate the pattern of interaction and instructional methods used for teaching physics and level of coverage of physics syllabus. The survey design was employed for the study in which questionnaire was…

  20. Investigation of capacitance characteristics in metal/high-k ...

    Indian Academy of Sciences (India)

    2017-08-21

    Aug 21, 2017 ... to investigate capacitance–voltage characteristics of metal– insulator (high k: Al2O3) semiconductor (p-Si) devices. We report on the effect of bias voltage, silicon substrate doping concentration, frequency and temperature on the elec- trical and dielectric properties of TiN/Al2O3/p-Si structure in. 1035 ...

  1. Breakdown of highly excited oxygen in a DC electric field

    International Nuclear Information System (INIS)

    Vagin, N.P.; Ionin, A.A.; Klimachev, Yu.M.; Sinitsin, D.V.; Yuryshev, N.N.; Deryugin, A.A.; Kochetov, I.V.; Napartovich, A.P.

    2000-01-01

    The breakdown of oxygen in a dc electric field is studied. A high concentration of oxygen molecules in the a 1 Δ g excited state is obtained in a purely chemical reactor. A decrease in the breakdown voltage at degrees of excitation exceeding 50% is observed. The theoretical decrement in the breakdown voltage obtained by solving the Boltzmann equation is in good agreement with the experimental data

  2. Optical investigation of effective permeability of dilute magnetic dielectrics with magnetic field

    Science.gov (United States)

    Banerjee, Ananya; Sarkar, A.

    2016-05-01

    The prime objective of this paper is to investigate the magnetic nature of dilute magnetic dielectrics (DMD) under variation of external magnetic field. The said variation is studied over developed nano-sized Gadolinium Oxide as a DMD system. The observed experimental field variation of the effective magnetic permeability is analyzed results of optical experiment. The experiment records the variation of Brewster angle of incident polarized LASER beam from the surface of developed DMD specimen with applied out of plane external magnetic field. The effective refractive index and hence relative magnetic permeability were estimated following electro-magnetic theory. The overall results obtained and agreement between theory and experiment are good.

  3. Optical investigation of effective permeability of dilute magnetic dielectrics with magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Ananya, E-mail: banerjee.ananya2008@gmail.com; Sarkar, A. [Dept. of Physics, Bijoy Krishna Girls’ College, 5/3 M.G. Road, Howrah 711101, W.B. (India)

    2016-05-06

    The prime objective of this paper is to investigate the magnetic nature of dilute magnetic dielectrics (DMD) under variation of external magnetic field. The said variation is studied over developed nano-sized Gadolinium Oxide as a DMD system. The observed experimental field variation of the effective magnetic permeability is analyzed results of optical experiment. The experiment records the variation of Brewster angle of incident polarized LASER beam from the surface of developed DMD specimen with applied out of plane external magnetic field. The effective refractive index and hence relative magnetic permeability were estimated following electro-magnetic theory. The overall results obtained and agreement between theory and experiment are good.

  4. New developments in pulsed fields at the US National High Magnetic Field Laboratory

    International Nuclear Information System (INIS)

    Campbell, L.J.; Parkin, D.M.; Rickel, D.G.; Pernambuco-Wise, P.

    1996-01-01

    Los Alamos National Laboratory is a member of a consortium (with Florida State University and the University of Florida) to operate the National High Magnetic Field Laboratory (NHMFL), with funding from the National Science Foundation and the State of Florida. Los Alamos provides unique resources for its component of NHMFL in the form of a 1.4 GW inertial storage motor-generator for high field pulsed magnets and infrastructure for fields generated by flux compression. The NHMFL provides a user facility open to all qualified users, develops magnet technology in association with the private sector, and advances science and technology opportunities. The magnets in service at Los Alamos are of three types. Starting with the pre-existing explosive flux compression capability in 1991, NHMFL added capacitor-driven magnets in December, 1992, and a 20 tesla superconducting magnet in January, 1993. The capacitor-driven magnets continue to grow in diversity and accessibility, with four magnet stations now available for several different magnet types. Two magnets of unprecedented size and strength are nearing completion of assembly and design, respectively. Under final assembly is a quasi-continuous magnet that contains 90 MJ of magnetic energy at full field, and being designed is a non-destructive 100 T magnet containing 140 MJ

  5. Young's moduli of cables for high field superconductive dipole magnet

    International Nuclear Information System (INIS)

    Yamada, Shunji; Shintomi, Takakazu.

    1983-01-01

    Superconductive dipole magnets for big accelerators are subjected to enormous electro-magnetic force, when they are operated with high field such as 10 Tesla. They should be constructed by means of superconductive cables, which have high Young's modulus, to obtain good performance. To develop such cables we measured the Young's moduli of cables for practical use of accelerator magnets. They are monolithic and compacted strand cables. We measured also Young's moduli of monolithic copper and brass cables for comparison. The obtained data showed the Young's moduli of 35 and 15 GPa for the monolithic and compacted strand cables, respectively. (author)

  6. Numerical Investigation of Ultrafast interaction between THz Fields and Crystalline Materials

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Clark, Stewart J.; Jepsen, Peter Uhd

    2014-01-01

    We present a quantum - mechanical molecular dynamics investigation of the interaction between strong single - cyc le THz pulses and ionic crystals . We find nonlinearities in the response of the CsI crystals at field strengths higher than 10 MV/cm.......We present a quantum - mechanical molecular dynamics investigation of the interaction between strong single - cyc le THz pulses and ionic crystals . We find nonlinearities in the response of the CsI crystals at field strengths higher than 10 MV/cm....

  7. An investigation of a flow field in one and half axial turbine stage

    Science.gov (United States)

    Němec, Martin; Jelínek, Tomáš; Milčák, Petr

    2017-09-01

    An investigation of one and half axial turbine stage configuration was carried out in a closed-loop wind tunnel. The investigation was addressed to that impact how the previous stage outlet flow field influences a flow structures in the next stator in steam multistage turbines. The detailed measurement behind the rotor and the second stator was performed with a pneumatic probes to gain a useful data for an impact analysis. Various rotor shroud clearances were also tested to capture the shroud outlet flow field influences.

  8. Field investigations on port non-tranquility caused by infra-gravity water waves

    OpenAIRE

    Najafi-Jilani, A.; Rahimi-Maleki, D.

    2010-01-01

    Field investigations have been carried out in two 60-day stages on the surf beat low frequency waves in Anzali port, one of the main commercial ports in Iran, located in southwest coast of the Caspian Sea. The characteristics of significant water waves were measured at three metering stations in the sea, one at the entrance of the port and three in the basin. The measured data were inspected to investigate the surf beat negative effects on the tranquility of the port. Using field measurements...

  9. Limited field investigation report for the 100-HR-1 Operable Unit

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-HR-1 Source Operable Unit LFI and the associated qualitative risk assessment (QRA) (WHC 1993a), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. A LFI Report is required, in accordance with the HPPS, when waste sites are to be considered for IRMs. The LFI is an integral part of the remedial investigation/feasibility study (RI/FS) or Resource Conservation and Recovery Act (RCRA) facility investigation/corrective measures study (RFI/CMS) and process and functions as a focused RI or RFI for selection of IRMs. The purpose of the report is to identify those sites that are recommended to remain as candidates for IRMs, provide a preliminary summary of site characterization studies, refine the conceptual model as needed, identify contaminant- and location-specific applicable or relevant and appropriate requirements (ARA), and provide a qualitative assessment of the risks associated with the sites. This assessment includes consideration of whether contaminant concentrations pose an unacceptable risk that warrants action through IRMs. The 100-HR-1 unit encompasses approximately 100 acres adjacent to the Columbia River shoreline. It contains waste units associated with the original plant facilities constructed to support the H Reactor. The area also contains evaporation basins which received liquid process wastes and nonroutine deposits of chemical wastes from the 300 Area, where fuel elements for the N Reactor were produced.

  10. Limited field investigation report for the 100-HR-1 Operable Unit

    International Nuclear Information System (INIS)

    1994-08-01

    This limited field investigation (LFI) report summarizes the data collection and analysis activities conducted during the 100-HR-1 Source Operable Unit LFI and the associated qualitative risk assessment (QRA) (WHC 1993a), and makes recommendations on the continued candidacy of high-priority sites for interim remedial measures (IRM). The results and recommendations presented in this report are generally independent of future land use scenarios. A LFI Report is required, in accordance with the HPPS, when waste sites are to be considered for IRMs. The LFI is an integral part of the remedial investigation/feasibility study (RI/FS) or Resource Conservation and Recovery Act (RCRA) facility investigation/corrective measures study (RFI/CMS) and process and functions as a focused RI or RFI for selection of IRMs. The purpose of the report is to identify those sites that are recommended to remain as candidates for IRMs, provide a preliminary summary of site characterization studies, refine the conceptual model as needed, identify contaminant- and location-specific applicable or relevant and appropriate requirements (ARA), and provide a qualitative assessment of the risks associated with the sites. This assessment includes consideration of whether contaminant concentrations pose an unacceptable risk that warrants action through IRMs. The 100-HR-1 unit encompasses approximately 100 acres adjacent to the Columbia River shoreline. It contains waste units associated with the original plant facilities constructed to support the H Reactor. The area also contains evaporation basins which received liquid process wastes and nonroutine deposits of chemical wastes from the 300 Area, where fuel elements for the N Reactor were produced

  11. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    Science.gov (United States)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  12. Experimental and theoretical investigation of high gradient acceleration

    International Nuclear Information System (INIS)

    Wurtele, J.S.; Bekefi, G.; Chen, C.; Chen, S.C.; Temkin, R.J.

    1993-01-01

    This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-AC02-91-ER40648, ''Experimental and Theoretical Investigations of High Gradient Acceleration''. This grant supports three research tasks: Task A consists of the design, fabrication and testing of a 17GHz RF photocathode gun, which can produce 2ps electron pulses with up to 1nC of charge at 2MeV energy and at a 1OHz repetition rate. Task B supports the testing of high gradient acceleration at 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders

  13. A novel high throughput method to investigate polymer dissolution.

    Science.gov (United States)

    Zhang, Ying; Mallapragada, Surya K; Narasimhan, Balaji

    2010-02-16

    The dissolution behavior of polystyrene (PS) in biodiesel was studied by developing a novel high throughput approach based on Fourier-transform infrared (FTIR) microscopy. A multiwell device for high throughput dissolution testing was fabricated using a photolithographic rapid prototyping method. The dissolution of PS films in each well was tracked by following the characteristic IR band of PS and the effect of PS molecular weight and temperature on the dissolution rate was simultaneously investigated. The results were validated with conventional gravimetric methods. The high throughput method can be extended to evaluate the dissolution profiles of a large number of samples, or to simultaneously investigate the effect of variables such as polydispersity, crystallinity, and mixed solvents. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Study of luminous phenomena observed on contaminated metallic surfaces submitted to high RF fields

    International Nuclear Information System (INIS)

    Maissa, S.; Junquera, T.; Fouaidy, M.; Le Goff, A.; Bonin, B.; Luong, M.; Safa, H.; Tan, J.

    1995-01-01

    The RF field emission from a sample subjected to high RF fields in a copper cavity has been investigated. The study is focused on the luminous emissions occurring on the RF surface simultaneously with the electron emission. The optical apparatus attached to the cavity permits to observe the evolution of the emitters and the direct effects of the surface conditioning. Also, the parameters of the emitted radiation (intensity, glowing duration, spectral distribution) may provide additional informations on the field emission phenomena. Some results concerning samples intentionally contaminated with particles (metallic or dielectric) are presented. (K.A.)

  15. Electric Field Simulations and Analysis for High Voltage High Power Medium Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Pei Huang

    2017-03-01

    Full Text Available The electronic power transformer (EPT raises concerns for its notable size and volume reduction compared with traditional line frequency transformers. Medium frequency transformers (MFTs are important components in high voltage and high power energy conversion systems such as EPTs. High voltage and high power make the reliable insulation design of MFT more difficult. In this paper, the influence of wire type and interleaved winding structure on the electric field distribution of MFT is discussed in detail. The electric field distributions for six kinds of typical non-interleaved windings with different wire types are researched using a 2-D finite element method (FEM. The electric field distributions for one non-interleaved winding and two interleaved windings are also studied using 2-D FEM. Furthermore, the maximum electric field intensities are obtained and compared. The results show that, in this case study, compared with foil conductor, smaller maximum electric field intensity can be achieved using litz wire in secondary winding. Besides, interleaving can increase the maximum electric field intensity when insulation distance is constant. The proposed method of studying the electric field distribution and analysis results are expected to make a contribution to the improvement of electric field distribution in transformers.

  16. The High Field Path to Practical Fusion Energy

    Science.gov (United States)

    Mumgaard, Robert; Whyte, D.; Greenwald, M.; Hartwig, Z.; Brunner, D.; Sorbom, B.; Marmar, E.; Minervini, J.; Bonoli, P.; Irby, J.; Labombard, B.; Terry, J.; Vieira, R.; Wukitch, S.

    2017-10-01

    We propose a faster, lower cost development path for fusion energy enabled by high temperature superconductors, devices at high magnetic field, innovative technologies and modern approaches to technology development. Timeliness, scale, and economic-viability are the drivers for fusion energy to combat climate change and aid economic development. The opportunities provided by high-temperature superconductors, innovative engineering and physics, and new organizational structures identified over the last few years open new possibilities for realizing practical fusion energy that could meet mid-century de-carbonization needs. We discuss re-factoring the fusion energy development path with an emphasis on concrete risk retirement strategies utilizing a modular approach based on the high-field tokamak that leverages the broader tokamak physics understanding of confinement, stability, and operational limits. Elements of this plan include development of high-temperature superconductor magnets, simplified immersion blankets, advanced long-leg divertors, a compact divertor test tokamak, efficient current drive, modular construction, and demountable magnet joints. An R&D plan culminating in the construction of an integrated pilot plant and test facility modeled on the ARC concept is presented.

  17. Investigation of Internal Amplification Effect at Planar ($p^{+}nn^{+}$) Structures Made of High Resistivity Silicon

    CERN Document Server

    Golubkov, S A; Gusev, K N; Egorov, N N; Zamiatin, N I; Katulina, S L; Kozlov, Yu F; Konkov, K A; Sandukovsky, V G; Sidorov, A I; Starostin, A S

    2004-01-01

    The first results of investigations of special strip and pixel silicon detectors are presented. The detector structures allow creating the high electric field (about 5\\cdot 10^{5} V/cm) near p-n junction. This field is high enough for avalanche multiplication of charge carriers. The possibility of internal amplification in the semiconductor detector similar to proportional amplification in gaseous counters is shown. The spectrum of -particles of the ^{238}Pu (E_{a}=5.5 MeV) demonstrates the "amplifying" peak at the energy of 70.2 MeV and energy resolution FWHM = 10.2 MeV

  18. Behavior of Rubber Materials under Exposure to High Electric Fields

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Holbøll, Joachim; Henriksen, M,

    2013-01-01

    The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence of the inte......The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence...

  19. Compliance with High-Intensity Radiated Fields Regulations - Emitter's Perspective

    Science.gov (United States)

    Statman, Joseph; Jamnejad, Vahraz; Nguyen, Lee

    2012-01-01

    NASA's Deep Space Network (DSN) uses high-power transmitters on its large antennas to communicate with spacecraft of NASA and its partner agencies. The prime reflectors of the DSN antennas are parabolic, at 34m and 70m in diameter. The DSN transmitters radiate Continuous Wave (CW) signals at 20 kW - 500 kW at X-band and S-band frequencies. The combination of antenna reflector size and high frequency results in a very narrow beam with extensive oscillating near-field pattern. Another unique feature of the DSN antennas is that they (and the radiated beam) move mostly at very slow sidereal rate, essentially identical in magnitude and at the opposite direction of Earth rotation.The DSN is in the process of revamping its documentation to provide analysis of the High Intensity Radiation Fields (HIRF) environment resulting from radio frequency radiation from DSN antennas for comparison to FAA regulations regarding certification of HIRF protection as outlined in the FAA regulations on HIRF protection for aircraft electrical and electronic systems (Title 14, Code of Federal Regulations (14 CFR) [section sign][section sign] 23.1308, 25.1317, 27.1317, and 29.1317).This paper presents work done at JPL, in consultation with the FAA. The work includes analysis of the radiated field structure created by the unique DSN emitters (combination of transmitters and antennas) and comparing it to the fields defined in the environments in the FAA regulations. The paper identifies areas that required special attention, including the implications of the very narrow beam of the DSN emitters and the sidereal rate motion. The paper derives the maximum emitter power allowed without mitigation and the mitigation zones, where required.Finally, the paper presents summary of the results of the analyses of the DSN emitters and the resulting DSN process documentation.

  20. Investigating the electronic portal imaging device for small radiation field measurements

    Directory of Open Access Journals (Sweden)

    Arpita Agarwal

    2017-01-01

    Full Text Available Purpose: With the advent of state-of-the-art treatment technologies, the use of small fields has increased, and dosimetry in small fields is highly challenging. In this study, the potential use of Varian electronic portal imaging device (EPID for small field measurements was explored for 6 and 15 MV photon beams. Materials and Methods: The output factors and profiles were measured for a range of jaw-collimated square field sizes starting from 0.8 cm×0.8 cm to 10 cm×10 cm using EPID. For evaluation purpose, reference data were acquired using Exradin A16 microionization chamber (0.007 cc for output factors and stereotactic field diode for profile measurements in a radiation field analyzer. Results: The output factors of EPID were in agreement with the reference data for field sizes down to 2 cm×2 cm and for 2 cm×2 cm; the difference in output factors was +2.06% for 6 MV and +1.56% for 15 MV. For the lowest field size studied (0.8 cm×0.8 cm, the differences were maximum; +16% for 6 MV and +23% for 15 MV photon beam. EPID profiles of both energies were closely matching with reference profiles for field sizes down to 2 cm×2 cm; however, penumbra and measured field size of EPID profiles were slightly lower compared to its counterpart. Conclusions: EPID is a viable option for profile and output factor measurements for field sizes down to 2 cm×2 cm in the absence of appropriate small field dosimeters.

  1. Reconstructing Grasping Motions from High-Frequency Local Field Potentials in Primary Motor Cortex

    OpenAIRE

    Zhuang, Jun; Truccolo, Wilson; Vargas-Irwin, Carlos; Donoghue, John P.

    2010-01-01

    Recent developments in neural interface systems hold the promise to restore movement in people with paralysis. In search of neural signals for control of neural interface systems (NISs), previous studies have investigated primarily single and multiunit activity, as well as low frequency local field potentials (LFPs). In this paper, we investigate the information content about grasping motion of a broad band high frequency LFP (200 Hz – 400 Hz) by classifying discrete grasp aperture states and...

  2. High Precision GNSS Guidance for Field Mobile Robots

    Directory of Open Access Journals (Sweden)

    Ladislav Jurišica

    2012-11-01

    Full Text Available In this paper, we discuss GNSS (Global Navigation Satellite System guidance for field mobile robots. Several GNSS systems and receivers, as well as multiple measurement methods and principles of GNSS systems are examined. We focus mainly on sources of errors and investigate diverse approaches for precise measuring and effective use of GNSS systems for real-time robot localization. The main body of the article compares two GNSS receivers and their measurement methods. We design, implement and evaluate several mathematical methods for precise robot localization.

  3. High Field Linear Magnetoresistance Sensors with Perpendicular Anisotropy L10-FePt Reference Layer

    Directory of Open Access Journals (Sweden)

    X. Liu

    2016-01-01

    Full Text Available High field linear magnetoresistance is an important feature for magnetic sensors applied in magnetic levitating train and high field positioning measurements. Here, we investigate linear magnetoresistance in Pt/FePt/ZnO/Fe/Pt multilayer magnetic sensor, where FePt and Fe ferromagnetic layers exhibit out-of-plane and in-plane magnetic anisotropy, respectively. Perpendicular anisotropy L10-FePt reference layer with large coercivity and high squareness ratio was obtained by in situ substrate heating. Linear magnetoresistance is observed in this sensor in a large range between +5 kOe and −5 kOe with the current parallel to the film plane. This L10-FePt based sensor is significant for the expansion of linear range and the simplification of preparation for future high field magnetic sensors.

  4. High ionization radiation field remote visualization device - shielding requirements

    International Nuclear Information System (INIS)

    Fernandez, Antonio P. Rodrigues; Omi, Nelson M.; Silveira, Carlos Gaia da; Calvo, Wilson A. Pajero

    2011-01-01

    The high activity sources manipulation hot-cells use special and very thick leaded glass windows. This window provides a single sight of what is being manipulated inside the hot-cell. The use of surveillance cameras would replace the leaded glass window, provide other sights and show more details of the manipulated pieces, using the zoom capacity. Online distant manipulation may be implemented, too. The limitation is their low ionizing radiation resistance. This low resistance also limited the useful time of robots made to explore or even fix problematic nuclear reactor core, industrial gamma irradiators and high radioactive leaks. This work is a part of the development of a high gamma field remote visualization device using commercial surveillance cameras. These cameras are cheap enough to be discarded after the use for some hours of use in an emergency application, some days or some months in routine applications. A radiation shield can be used but it cannot block the camera sight which is the shield weakness. Estimates of the camera and its electronics resistance may be made knowing each component behavior. This knowledge is also used to determine the optical sensor type and the lens material, too. A better approach will be obtained with the commercial cameras working inside a high gamma field, like the one inside of the IPEN Multipurpose Irradiator. The goal of this work is to establish the radiation shielding needed to extend the camera's useful time to hours, days or months, depending on the application needs. (author)

  5. Advances in High-Field BOLD fMRI

    Directory of Open Access Journals (Sweden)

    Markus Barth

    2011-11-01

    Full Text Available This review article examines the current state of BOLD fMRI at a high magnetic field strength of 7 Tesla. The following aspects are covered: a short description of the BOLD contrast, spatial and temporal resolution, BOLD sensitivity, localization and spatial specificity, technical challenges as well as an outlook on future developments are given. It is shown that the main technical challenges of performing BOLD fMRI at high magnetic field strengths—namely development of array coils, imaging sequences and parallel imaging reconstruction—have been solved successfully. The combination of these developments has lead to the availability of high-resolution BOLD fMRI protocols that are able to cover the whole brain with a repetition time (TR shorter than 3 s. The structural information available from these high-resolution fMRI images itself is already very detailed, which helps to co-localize structure and function. Potential future applications include whole-brain connectivity analysis on a laminar resolution and single subject examinations.

  6. The magnetic field investigation on the ARASE (ERG) mission: Data characteristics and initial scientific results

    Science.gov (United States)

    Matsuoka, A.; Teramoto, M.; Nomura, R.; Nose, M.; Fujimoto, A.; Tanaka, Y.; Shinohara, M.; Nagatsuma, T.; Shiokawa, K.; Obana, Y.; Miyoshi, Y.; Takashima, T.; Shinohara, I.

    2017-12-01

    The ARASE (ERG) satellite was successfully launched on December 20 2016. A fluxgate magnetometer (MGF) was built for the ARASE satellite to measure DC and low-frequency magnetic field. The requirements to the magnetic field measurements by ARASE was defined as (1) accuracy of the absolute field intensity is within 5 nT (2) angular accuracy of the field direction is within 1 degree (3) measurement frequency range is from DC to 60Hz or wider. MGF measures the vector magnetic field with the original sampling frequency of 256 Hz. The dynamic range is switched between +/-8000nT and +/- 60000nT according to the background field intensity. The MGF initial checkout was carried on January 10th 2017, when the MGF normal performance and downlinked data were confirmed. The 5-m length MAST for the sensor was deployed on 17th January. The nominal operation of MGF started in March 2017. The MGF data are calibrated based on the results from the ground experiments and in-orbit data analysis. The MGF CDF files are distributed by the ARASE Science Center and available by Space Physics Environment Data Analysis Software (SPEDAS). The acceleration process of the charged particles in the inner magnetosphere is considered to be closely related to the deformation and perturbation of the magnetic field. Accurate measurement of the magnetic field is required to understand the acceleration mechanism of the charged particles, which is one of the major scientific objectives of the ARASE mission. We designed a fluxgate magnetometer which is optimized to investigate following topics; (1) accurate measurement of the background magnetic field - the deformation of the magnetic field and its relationship with the particle acceleration. (2) MHD waves - measurement of the ULF electromagnetic waves of frequencies about 1mHz (Pc4-5), and investigation of the radiation-belt electrons radially diffused by the resonance with the ULF waves. (3) EMIC waves - measurement of the electromagnetic ion

  7. Theory of high-field electronic transport in bulk ZnS and ZnSe

    Science.gov (United States)

    Brennan, Kevin

    1988-01-01

    This paper theoretically investigates the nature of electronic transport and the high-energy tails of the electron distribution functions in bulk ZnSe and ZnS as a function of the applied electric field were investigated using calculations based on an ensemble Monte Carlo model. The calculations include the full details of the first two conduction bands as well as the full-order treatment of the electron-phonon scattering mechanisms. Results of high-field electronic transport calculations show that the electron energy distribution function is significanty cooler in ZnS than in ZnSe at comparable electric field strengths. The cooler distribution in ZnS is due to the much greater electron scattering rate. Consequently, it is more difficult to achieve carrier heating to comparable energies in ZnS than in ZnSe.

  8. Cold induced peripheral vasodilation at high altitudes- a field study

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ruiten, H.J.A. van

    2000-01-01

    A significant reduction in cold-induced vasodilation (CIVD) is observed at high altitudes. No agreement is found in the literature about acclimatization effects on CIVD. Two studies were performed to investigate the effect of altitude acclimatization on CIVD. In the first study 13 male subjects

  9. ALPHA (Adjustable Long Pulse High-Field Apparatus)

    Science.gov (United States)

    Birmingham, W. J.; Bates, E. M.; Romero-Talamas, C. A.; Rivera, W. F.

    2017-10-01

    The Dusty Plasma Laboratory (DPL) at the University of Maryland, Baltimore County (UMBC) is now finalizing the design and fabricating components for ALPHA, a high-field Bitter-type electromagnet to be used for magnetized dusty plasma experiments. When the system is complete, ALPHA will be programmable to dynamically increase or decrease fields of up to 10 T for nominally 10 seconds and up to several minutes. The magnet dimensions as well as power and cooling requirements were optimized according to a genetic algorithm developed in the DPL. The cooling channel pattern design was obtained using an analytic methodology also developed in the DPL. The final design parameters as well as the predicted performance characteristics of the magnetic core, the water cooling shell, and the DC power source are presented.

  10. Effect of temperature on Acoustic Evaluation of standing trees and logs: Part 2: Field Investigation

    Science.gov (United States)

    Shan Gao; Xiping Wang; Lihai Wang; R. Bruce Allison

    2013-01-01

    The objectives of this study were to investigate the effect of seasonal temperature changes on acoustic velocity measured on standing trees and green logs and to develop models for compensating temperature differences because acoustic measurements are performed in different climates and seasons. Field testing was conducted on 20 red pine (Pinus resinosa...

  11. The Investigation of Screening of Chromoelectric and Chromomagnetic Fields in QGP in Noncovariant Gauges

    International Nuclear Information System (INIS)

    Veliev, E.S.

    2004-01-01

    According to Thermal Quantum Chromodynamics (TQCD) hadron matter may be exist in different phase states, in particular, in the form of quark-gluon plasma (QGP). The aim of the present work is to investigate the screening of chromoelectric and chromomagnetic fields in QGP in temporal gauge. In temporal gauge gluon propagator has the unphysical poles. Hence, in the gluon self energy diagram calculations the singularities appear. In order to remove these singularities we used Leibbrandt-Mandelstam prescription. We obtained that chromoelectric fields are screened, but chromomagnetic fields are not screened. In coordinate space, the screening of chromoelectric fields reduces the range of gauge interactions. In momentum space, it contributes to regulate the infrared behavior of the various n-point Green functions. Also, it is shown that the obtained results are gauge invariant

  12. Methanol masers reveal the magnetic field of the high-mass protostar IRAS 18089-1732

    Science.gov (United States)

    Dall'Olio, D.; Vlemmings, W. H. T.; Surcis, G.; Beuther, H.; Lankhaar, B.; Persson, M. V.; Richards, A. M. S.; Varenius, E.

    2017-11-01

    Context. The importance of the magnetic field in high-mass-star formation is not yet fully clear and there are still many open questions concerning its role in the accretion processes and generation of jets and outflows. In the past few years, masers have been successfully used to probe the magnetic field morphology and strength at scales of a few au around massive protostars, by measuring linear polarisation angles and Zeeman splitting. The massive protostar IRAS 18089-1732 is a well studied high-mass-star forming region, showing a hot core chemistry and a disc-outflow system. Previous SMA observations of polarised dust revealed an ordered magnetic field oriented around the disc of IRAS 18089-1732. Aims: We want to determine the magnetic field in the dense region probed by 6.7 GHz methanol maser observations and compare it with observations in dust continuum polarisation, to investigate how the magnetic field in the compact maser region relates to the large-scale field around massive protostars. Methods: We reduced MERLIN observations at 6.7 GHz of IRAS 18089-1732 and we analysed the polarised emission by methanol masers. Results: Our MERLIN observations show that the magnetic field in the 6.7 GHz methanol maser region is consistent with the magnetic field constrained by the SMA dust polarisation observations. A tentative detection of circularly polarised line emission is also presented. Conclusions: We found that the magnetic field in the maser region has the same orientation as in the disk. Thus the large-scale field component, even at the au scale of the masers, dominates over any small-scale field fluctuations. We obtained, from the circular polarisation tentative detection, a field strength along the line of sight of 5.5 mG which appeared to be consistent with the previous estimates.

  13. High-resolution field shaping utilizing a masked multileaf collimator.

    Science.gov (United States)

    Williams, P C; Cooper, P

    2000-08-01

    Multileaf collimators (MLCs) have become an important tool in the modern radiotherapy department. However, the current limit of resolution (1 cm at isocentre) can be too coarse for acceptable shielding of all fields. A number of mini- and micro-MLCs have been developed, with thinner leaves to achieve approved resolution. Currently however, such devices are limited to modest field sizes and stereotactic applications. This paper proposes a new method of high-resolution beam collimation by use of a tertiary grid collimator situated below the conventional MLC. The width of each slit in the grid is a submultiple of the MLC width. A composite shaped field is thus built up from a series of subfields, with the main MLC defining the length of each strip within each subfield. Presented here are initial findings using a prototype device. The beam uniformity achievable with such a device was examined by measuring transmission profiles through the grid using a diode. Profiles thus measured were then copied and superposed to generate composite beams, from which the uniformity achievable could be assessed. With the average dose across the profile normalized to 100%, hot spots up to 5.0% and troughs of 3% were identified for a composite beam of 2 x 5.0 mm grids, as measured at Dmax for a 6 MV beam. For a beam composed from 4 x 2.5 mm grids, the maximum across the profile was 3.0% above the average, and the minimum 2.5% below. Actual composite profiles were also formed using the integrating properties of film, with the subfield indexing performed using an engineering positioning stage. The beam uniformity for these fields compared well with that achieved in theory using the diode measurements. Finally sine wave patterns were generated to demonstrate the potential improvements in field shaping and conformity using this device as opposed to the conventional MLC alone. The scalloping effect on the field edge commonly seen on MLC fields was appreciably reduced by use of 2 x 5.0 mm

  14. High-resolution field shaping utilizing a masked multileaf collimator

    International Nuclear Information System (INIS)

    Williams, P.C.; Cooper, P.

    2000-01-01

    Multileaf collimators (MLCs) have become an important tool in the modern radiotherapy department. However, the current limit of resolution (1 cm at isocentre) can be too coarse for acceptable shielding of all fields. A number of mini- and micro-MLCs have been developed, with thinner leaves to achieve approved resolution. Currently however, such devices are limited to modest field sizes and stereotactic applications. This paper proposes a new method of high-resolution beam collimation by use of a tertiary grid collimator situated below the conventional MLC. The width of each slit in the grid is a submultiple of the MLC width. A composite shaped field is thus built up from a series of subfields, with the main MLC defining the length of each strip within each subfield. Presented here are initial findings using a prototype device. The beam uniformity achievable with such a device was examined by measuring transmission profiles through the grid using a diode. Profiles thus measured were then copied and superposed to generate composite beams, from which the uniformity achievable could be assessed. With the average dose across the profile normalized to 100%, hot spots up to 5.0% and troughs of 3% were identified for a composite beam of 2x5.0 mm grids, as measured at D max for a 6 MV beam. For a beam composed from 4x2.5 mm grids, the maximum across the profile was 3.0% above the average, and the minimum 2.5% below. Actual composite profiles were also formed using the integrating properties of film, with the subfield indexing performed using an engineering positioning stage. The beam uniformity for these fields compared well with that achieved in theory using the diode measurements. Finally sine wave patterns were generated to demonstrate the potential improvements in field shaping and conformity using this device as opposed to the conventional MLC alone. The scalloping effect on the field edge commonly seen on MLC fields was appreciably reduced by use of 2x5.0 mm grids

  15. Investigation of magnetic drift on transport of plasma across magnetic field

    International Nuclear Information System (INIS)

    Hazarika, Parismita; Chakraborty, Monojit; Das, Bidyut; Bandyopadhyay, Mainak

    2015-01-01

    When a metallic body is inserted inside plasma chamber it is always associated with sheath which depends on plasma and wall condition. The effect of sheath formed in the magnetic drift and magnetic field direction on cross field plasma transport has been investigated in a double Plasma device (DPD). The drifts exist inside the chamber in the transverse magnetic field (TMF) region in a direction perpendicular to both magnetic field direction and axis of the DPD chamber. The sheath are formed in the magnetic drift direction in the experimental chamber is due to the insertion of two metallic plates in these directions and in the magnetic field direction sheath is formed at the surface of the TMF channels. These metallic plates are inserted in order to obstruct the magnetic drift so that we can minimised the loss of plasma along drift direction and density in the target region is expected to increase due to the obstruction. It ultimately improves the negative ion formation parameters. The formation of sheath in the transverse magnetic field region is studied by applying electric field both parallel and antiparallel to drift direction. Data are acquired by Langmuir probe in source and target region of our chamber. (author)

  16. Flow field investigations in rotating facilities by means of stationary PIV systems

    International Nuclear Information System (INIS)

    Armellini, A; Mucignat, C; Casarsa, L; Giannattasio, P

    2012-01-01

    The flow field inside rotating test sections can be investigated by means of particle image velocimetry (PIV) operated in the phase-locked mode. With this experimental approach, the measurement system is kept fixed and it is synchronized with the periodical passage of the test section. Therefore, the direct output of the PIV measurements is the absolute velocity field, while the relative one is indirectly obtained from proper data processing that relies on accurate knowledge of the peripheral velocity field. This work provides an uncertainty analysis about the evaluation of the peripheral displacement field in phase-locked PIV measurements. The analysis leads to the detection of the levels of accuracy required in the estimation of both the angular velocity and the position of the center of rotation to ensure correct evaluation of the peripheral displacement field. In this regard, a simple methodology is proposed to evaluate the center of rotation position with an accuracy below 1 px. Finally, a procedure to pre-process the PIV images by subtracting the peripheral displacement is described. The advantages of its implementation are highlighted by the comparison with the performance of a more standard methodology where the peripheral field is subtracted from the absolute velocity field and not directly from the PIV raw data

  17. Investigation of protein detection parameters using nanofunctionalized organic field-effect transistors.

    Science.gov (United States)

    Hammock, Mallory L; Knopfmacher, Oren; Naab, Benjamin D; Tok, Jeffrey B-H; Bao, Zhenan

    2013-05-28

    Biodetection using organic field-effect transistors (OFETs) is gaining increasing interest for applications as diverse as food security, environmental monitoring, and medical diagnostics. However, there still lacks a comprehensive, empirical study on the fundamental limits of OFET sensors. In this paper, we present a thorough study of the various parameters affecting biosensing using an OFET decorated with gold nanoparticle (AuNP) binding sites. These parameters include the spacing between receptors, pH of the buffer, and ionic strength of the buffer. To this end, we employed the thrombin protein and its corresponding DNA binding aptamer to form our model detection system. We demonstrate a detection limit of 100 pM for this protein with high selectivity over other proteases in situ. We describe herein a feasible approach for protein detection with OFETs and a thorough investigation of parameters governing biodetection events using OFETs. Our obtained results should provide important guidelines to tailor the sensor's dynamic range to suit other desired OFET-based biodetection applications.

  18. High Field Studies for CLIC Accelerating Structures Development

    CERN Document Server

    Profatilova, I

    2017-01-01

    Compact Linear Collider RF structures need to be able to achieve the very high average accelerating gradient of 100 MV/m. One of the main challenges in reaching such high accelerating gradients is to avoid vacuum electrical breakdown within CLIC accelerating structures. Accelerating structure tests are carried out in the klystron-based test stands known as the XBoxes. In order to investigate vacuum breakdown phenomena and its statistical characteristics in a simpler system and get results in a faster way, pulsed dc systems have been developed at CERN. To acquire sufficient breakdown data in a reasonable period of time, high repetition rate pulse generators are used in the systems for breakdown studies, so-called pulsed dc system. This paper describes the pulsed dc systems and the two high repetition rate circuits, which produce high-voltage pulses for it, available at CERN.

  19. High Field Side MHD Activity During Local Helicity Injection

    Science.gov (United States)

    Pachicano, J. L.; Bongard, M. W.; Fonck, R. J.; Perry, J. M.; Reusch, J. A.; Richner, N. J.

    2017-10-01

    MHD is an essential part of understanding the mechanism for local helicity injection (LHI) current drive. The new high field side (HFS) LHI system on the Pegasus ST permits new tests of recent NIMROD simulations. In that model, LHI current streams in the plasma edge undergo large-scale reconnection events, leading to current drive. This produces bursty n = 1 activity around 30 kHz on low field side (LFS) Mirnov coils, consistent with experiment. The simulations also feature coherent injector streams winding down the center column. Improvements to the core high-resolution poloidal Mirnov array with Cat7A Ethernet cabling and differentially driven signal processing eliminated EMI-driven switching noise, enabling detailed spectral analysis. Preliminary results from the recovered HFS poloidal Mirnov coils suggest n = 1 activity is present at the top of the vessel core, but does not persist down the centerstack. HFS LHI experiments can exhibit an operating regime where the high amplitude MHD is abruptly reduced by more than an order of magnitude on LFS Mirnov coils, leading to higher plasma current and improved particle confinement. This reduction is not observed on the HFS midplane magnetics. Instead, they show broadband turbulence-like magnetic features with near consistent amplitude in a frequency range of 90-200 kHz. Work supported by US DOE Grant DE-FG02-96ER54375.

  20. High-temperature structural phase transitions in neighborite: a high-resolution neutron powder diffraction investigation

    Science.gov (United States)

    Knight, Kevin S.; Price, G. David; Stuart, John A.; Wood, Ian G.

    2015-01-01

    The nature of the apparently continuous structural phase transition at 1,049 K in the perovskite-structured, MgSiO3 isomorph, neighborite (NaMgF3), from the orthorhombic ( Pbnm) hettotype phase to the cubic () aristotype structure, has been re-investigated using high-resolution, time-of-flight neutron powder diffraction. Using data collected at 1 K intervals close to the nominal phase transition temperature, the temperature dependence of the intensities of superlattice reflections at the M point and the R point of the pseudocubic Brillouin zone indicate the existence of a new intermediate tetragonal phase in space group P4/ mbm, with a narrow phase field extending from ~1,046.5 to ~1,048.5 K, at ambient pressure. Group theoretical analysis shows that the structural transitions identified in this study, Pbnm- P4/ mbm, and P4/ mbm-, are permitted to be second order. The observation of the tetragonal phase resolves the longstanding issue of why the high-temperature phase transition, previously identified as Pbnm-, and which would be expected to be first order under Landau theory, is in fact found to be continuous. Analysis of the pseudocubic shear strain shows it to vary with a critical exponent of 0.5 implying that the phase transition from Pbnm to P4/ mbm is tricritical in character. The large librational modes that exist in the MgF6 octahedron at high temperature, and the use of Gaussian probability density functions to describe atomic displacements, result in apparent bond shortening in the Mg-F distances, making mode amplitude determination an unreliable method for determination of the critical exponent from internal coordinates. Crystal structures are reported for the three phases of NaMgF3 at 1,033 K ( Pbnm), 1,047 K ( P4/ mbm) and 1,049 K ().

  1. The field investigation on thermal comfort of tent in early autumn of Tianjin

    Directory of Open Access Journals (Sweden)

    Yang Hao

    2016-01-01

    Full Text Available In a university campus in Tianjin, four tents were set up to investigate the thermal environment and thermal comfort. Both the field investigation and questionnaires were adopted in this experiment. Two hundred people were investigated, and two hundred questionnaires were gotten. The results show that the thermal comfort zone of officers and soldiers is 24°C to 28°C in early fall, it is a wide range. There is a big error between the PMV index and the actual survey results, PMV calculation index is not accurate in tents environment. The results will have a significant effect on improving the thermal comfort of tents..

  2. Investigation of ultra violet (UV) resistance for high strength fibers

    Science.gov (United States)

    Said, M. A.; Dingwall, Brenda; Gupta, A.; Seyam, A. M.; Mock, G.; Theyson, T.

    Ultra long duration balloons (ULDB), currently under development by the National Aeronautics and Space Administration (NASA), requires the use of high strength fibers in the selected super-pressure pumpkin design. The pumpkin shape balloon concept allows clear separation of the load transferring functions of the major structural elements of the pneumatic envelope, the tendons and the film. Essentially, the film provides the gas barrier and transfers only local pressure load to the tendons. The tendons, in the mean time, provide the global pressure containing strength. In that manner, the strength requirement for the film only depends on local parameters. The tendon is made of p-phenylene-2,6-benzobisoxazole (PBO) fibers, which is selected due to its high strength to weight ratio when compared to other high performance, commercially available, fibers. High strength fibers, however, are known to degrade upon exposure to light, particularly at short wavelengths. This paper reports the results of an investigation of the resistance of four commercial high strength fibers to ultra violet (UV) exposure. The results indicate that exposing high strength fibers in continuous yarn form to UV led to serious loss in strength of the fibers except for Spectra® fibers. The adverse changes in mechanical behavior occurred over short duration of exposure compared to the 100 day duration targeted for these missions. UV blocking finishes to improve the UV resistance of these fibers are being investigated. The application of these specially formulated coatings is expected to lead to significant improvement of the UV resistance of these high performance fibers. In this publication, we report on the mechanical behavior of the fibers pre- and post-exposure to UV, but without application of the blocking finishes.

  3. Magnetic measurements on transition metal compounds and dilute alloys in high magnetic fields

    International Nuclear Information System (INIS)

    Smit, J.J.

    1979-01-01

    A number of experiments are described which have in common the application of high magnetic fields to the study of magnetic ordering phenomena at low temperatures. A pulsed-field magnet is used, capable of producing field pulses during a time period of about 20 ms and maximum fields that are in the range of 40-50 Tesla. In some cases additional data have been taken in superconducting magnets with maximum fields up to 11 T. After a description of the experimental equipments a series of measurements on quasi linear chain anti-ferromagnets is given. Experiments are described on S=1 systems for which the spin-triplet is split up by the crystal field in such a way that the ground state is a nonmagnetic singlet. The upper doublet splits if a field is applied, and if the Zeeman energy is sufficiently strong one of the doublet levels will cross the singlet, yielding a magnetic ground state. The magnetization and the field and frequency dependence of the differential susceptibility of these systems have been studied. The crystal field splitting parameter D and the exchange J are determined. Magnetic measurements are presented on compounds in which the magnetic ions form dimeric or tetrameric clusters of spins, the intercluster interactions being very small. The aim of this investigation was to characterize the magnetic behaviour of these systems, and to obtain estimates of the antiferromagnetic superexchange interactions. Lastly, a study is reported on three prototype examples of metallic spin glasses. (Auth.)

  4. High field properties of NbN ribbon conductors

    International Nuclear Information System (INIS)

    Capone, D.W. II; Kampwirth, R.T.; Gray, K.E.

    1985-08-01

    This paper reports the first high field measurements on ribbon conductors composed of NbN and Cu deposited onto Hastelloy ribbons. These ribbons are 5 to 8 cm long, 1/8'' wide, and have several microns of NbN, covered with several microns of Cu, deposited onto one side. Such samples have a T/sub c/ approx. 14.5 K, H/sub c2/ (2.0 K) approx. 26 T in the parallel direction and J/sub c/ (20 T, 2.0 K) up to 3 x 10 4 A/cm 2

  5. Electric fields and electrostatic potentials in the high latitude ionosphere

    Science.gov (United States)

    Banks, P. M.; Saint Maurice, J.-P.; Heelis, R. A.; Hanson, W. B.

    1981-01-01

    Recent interpretive studies of electric field-driven ionospheric plasma convection data from the AE-C satellite are described, where the instruments employed include an ion drift meter and an ion-retarding potential analyzer. Electrostatic potential curves are derived from ion drift velocity measurements for high-latitude segments of the satellite's orbit. The potential curves are shown to be useful in determining the character of the global electrostatic potential pattern, with emphasis on the separation of convective cells. Results are given for six orbits, with attention to the mid-day auroral region.

  6. High Field Magnet R and D in the USA

    International Nuclear Information System (INIS)

    Gourlay, S.A.

    2003-01-01

    Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb 3 Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed.

  7. High Field Magnet R and D in the USA

    International Nuclear Information System (INIS)

    Gourlay, Stephen A.

    2003-01-01

    Accelerator magnet technology is currently dominated by the use of NbTi superconductor. New and more demanding applications for superconducting accelerator magnets require the use of alternative materials. Several programs in the US are taking advantage of recent improvements in Nb 3 Sn to develop high field magnets for new applications. Highlights and challenges of the US R and D program are presented along with the status of conductor development. In addition, a new R and D focus, the US LHC Accelerator Research Program, will be discussed

  8. High field magnetic behavior in Boron doped Fe{sub 2}VAl Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesh, Ch., E-mail: venkyphysicsiitm@gmail.com [Department of Physics, Indian Institute of Technology, Kharagpur (India); DCMP & MS, Tata Institute of Fundamental Research, Mumbai (India); Vasundhara, M., E-mail: vasu.mutta@gmail.com [Materials Science and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR, Trivandrum 695019 (India); Srinivas, V. [Department of Physics, Indian Institute of Technology, Chennai (India); Rao, V.V. [Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur (India)

    2016-11-15

    We have investigated the magnetic behavior of Fe{sub 2}VAl{sub 1−x}B{sub x} (x=0, 0.03, 0.06 and 0.1) alloys under high temperature and high magnetic field conditions separately. Although, the low temperature DC magnetization data for the alloys above x>0 show clear magnetic transitions, the zero field cooled (ZFC) and field cooled (FC) curves indicate the presence of spin cluster like features. Further, critical exponent (γ) deduced from the initial susceptibility above the T{sub c}, does not agree with standard models derived for 3 dimensional long range magnetic systems. The deviation in γ values are consistent with the short range magnetic nature of these alloys. We further extend the analysis of magnetic behavior by carrying the magnetization measurements at high temperatures and high magnetic fields distinctly. We mainly emphasize the following observations; (i) The magnetic hysteresis loops show sharp upturns at lower fields even at 900 K for all the alloys. (ii) High temperature inverse susceptibility do not overlap until T=900 K, indicating the persistent short range magnetic correlations even at high temperatures. (iii) The Arrott's plot of magnetization data shows spontaneous moment (M{sub S}) for the x=0 alloy at higher magnetic fields which is absent at lower fields (<50 kOe), while the Boron doped samples show feeble M{sub S} at lower fields. The origin of this short range correlation is due to presence of dilute magnetic heterogeneous phases which are not detected from the X-ray diffraction method. - Highlights: • Short range magnetic character has been confirmed by the critical exponents analysis. • Magnetoresistace is about −14% with non-saturating tendency even at 150 kOe for Fe{sub 2}VAl alloy. • Boron doped Fe{sub 2}VAl alloys show a weak magnetism even at T=900 K.

  9. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    International Nuclear Information System (INIS)

    Cunha, Elisete L.; Schimitberger, Thiago

    2017-01-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm -1 and 3271 cm -1 , with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  10. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Elisete L.; Schimitberger, Thiago, E-mail: elisete.cunha@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Oliveira, Cristiana M.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm{sup -1} and 3271 cm{sup -1}, with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  11. High magnetic field magnetization of a new triangular lattice antiferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, H. D. [Univ. of Tennessee, Knoxville, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab. (MagLab); Stritzinger, Laurel Elaine Winter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-23

    In CsV(MoO4)2, the magnetic V3+ ions with octahedral oxygen-coordination form a geometrically frustrated triangular lattice. So fare, there is no magnetic properties reported on it. Recently, we successfully grew single crystals of CsV(MoO4)2 by using flux method. The susceptibility shows a sharp drop around 24 K, representing a long range magnetic ordering. To understand the physical properties of this new triangular lattice antiferromagnet (TLAF), we pursued high field magnetization measurements to answer two questions: (i) what is the saturation field, which will be very useful to calculate the exchange interaction of the system? (ii) Will it exhibit spin state transition, such as the up up down phase with 1/3-saturation moment as other TLAFs? Recently, we performed VSM measurements in Cell 8, Tallahassee, NHMFL, the results show that the magnetization reaches 0.38 MuB at 34 T, which is just 19% of the full moment of 2 MuB for V3+ (3d2) ions. Apparently we need higher field to reach 1/3 value or full moment.

  12. A NUMERICAL INVESTIGATION OF EFFECT OF MAGNETIC FIELD ON HEAT CONVECTION WITH VARIABLE PHYSICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Ziyaddin RECEBLİ

    2008-01-01

    Full Text Available In some studies, the effect of magnetic field on heat convection has been investigated given that physical properties are constant regardless of temperature. The effect of magnetic field on heat convection and fluids whose physical properties change by temperature has been investigated in this study as physical properties of fluids change by the effect of temperature. Momentum, continuity and energy equations including electromagnetic force affecting the fluid were used in the solution. Temperatures at axial and radial directions and Nusselt numbers were calculated depending on magnetic field intensity and other physical properties of fluid by solving the equation system written in cylindrical coordinates system by means of one of the numerical methods which is finite difference method. According to results, velocity and temperature of the cooled fluid decreased following an increase in the intensity of magnetic field placed vertically to flow direction. As determined in the previous one, this study also indicated that the increase in Reynolds number increases Nusselt number, and increasing the effect of magnetic field decreases Nusselt number. The theoretical results of the present study are in conformity with the results of our previous one.

  13. Theoretical investigation of the breakdown electric field of SiC polymorphs

    Science.gov (United States)

    Yamaguchi, Kikou; Kobayashi, Daisuke; Yamamoto, Tomoyuki; Hirose, Kazuyuki

    2018-03-01

    The breakdown electric field of several SiC polymorphs has been investigated theoretically using a concept of "recovery rate," which is obtained by first principles calculations. A good relationship between the experimental breakdown electric fields and the calculated recovery rate of 4H-, 6H-, and 3C-SiC was obtained. In order to examine the stability of SiC polymorphs, the total electronic energies of various types of SiC crystal structures were calculated. Here, two candidates of polymorphs-GeS-type- and 2H-SiC-with energies comparable to those of experimentally well-established structures, have been obtained. The breakdown electric fields of these two polymorphs were estimated using a relationship obtained from the results of 4H-, 6H-, and 3C-SiC. This indicates that one of these polymorphs, GeS-type-SiC, has higher breakdown electric field than any other SiC polymorphs. In addition to the investigation with the recovery rate, relationship between experimental breakdown electric field and calculated band gap with recently developed accurate electron-correlation potential has been also discussed.

  14. A Theoretical Investigation of Mode-Locking Phenomena in Reversed Field Pinches

    International Nuclear Information System (INIS)

    Richard Fitzpatrick

    2004-01-01

    OAK-B135 This paper investigates the formation and breakup of the ''slinky mode'' in an RFP using analytic techniques previously employed to examine mode locking phenomena in tokamaks. The slinky mode is a toroidally localized, coherent interference pattern in the magnetic field which co-rotates with the plasma at the reversal surface. This mode forms, as a result of the nonlinear coupling of multiple m = 1 core tearing modes, via a bifurcation which is similar to that by which toroidally coupled tearing modes lock together in a tokamak. The slinky mode breaks up via a second bifurcation which is similar to that by which toroidally coupled tearing modes in a tokamak unlock. However, the typical m = 1 mode amplitude below which slinky breakup is triggered is much smaller than that above which slinky formation occurs. Analytic expressions for the slinky formation and breakup thresholds are obtained in all regimes of physical interest. The locking of the slinky mode to a static error-field is also investigated analytically. Either the error-field arrests the rotation of the plasma at the reversal surface before the formation of the slinky mode, so that the mode subsequently forms as a non-rotating mode, or the slinky mode forms as a rotating mode and subsequently locks to the error-field. Analytic expressions for the locking and unlocking thresholds are obtained in all regimes of physical interest. The problems associated with a locked slinky mode can be alleviated by canceling out the accidentally produced error-field responsible for locking the slinky mode, using a deliberately created ''control'' error-field. Alternatively, the locking angle of the slinky mode can be swept toroidally by rotating the control field

  15. A theoretical investigation of mode-locking phenomena in reversed field pinches

    Energy Technology Data Exchange (ETDEWEB)

    Richard Fitzpatrick

    2004-03-17

    OAK-B135 This paper investigates the formation and breakup of the ''slinky mode'' in an RFP using analytic techniques previously employed to examine mode locking phenomena in tokamaks. The slinky mode is a toroidally localized, coherent interference pattern in the magnetic field which co-rotates with the plasma at the reversal surface. This mode forms, as a result of the nonlinear coupling of multiple m = 1 core tearing modes, via a bifurcation which is similar to that by which toroidally coupled tearing modes lock together in a tokamak. The slinky mode breaks up via a second bifurcation which is similar to that by which toroidally coupled tearing modes in a tokamak unlock. However, the typical m = 1 mode amplitude below which slinky breakup is triggered is much smaller than that above which slinky formation occurs. Analytic expressions for the slinky formation and breakup thresholds are obtained in all regimes of physical interest. The locking of the slinky mode to a static error-field is also investigated analytically. Either the error-field arrests the rotation of the plasma at the reversal surface before the formation of the slinky mode, so that the mode subsequently forms as a non-rotating mode, or the slinky mode forms as a rotating mode and subsequently locks to the error-field. Analytic expressions for the locking and unlocking thresholds are obtained in all regimes of physical interest. The problems associated with a locked slinky mode can be alleviated by canceling out the accidentally produced error-field responsible for locking the slinky mode, using a deliberately created ''control'' error-field. Alternatively, the locking angle of the slinky mode can be swept toroidally by rotating the control field.

  16. A Theoretical Investigation of Mode-Locking Phenomena in Reversed Field Pinches

    Energy Technology Data Exchange (ETDEWEB)

    Richard Fitzpatrick

    2004-04-07

    OAK-B135 This paper investigates the formation and breakup of the ''slinky mode'' in an RFP using analytic techniques previously employed to examine mode locking phenomena in tokamaks. The slinky mode is a toroidally localized, coherent interference pattern in the magnetic field which co-rotates with the plasma at the reversal surface. This mode forms, as a result of the nonlinear coupling of multiple m = 1 core tearing modes, via a bifurcation which is similar to that by which toroidally coupled tearing modes lock together in a tokamak. The slinky mode breaks up via a second bifurcation which is similar to that by which toroidally coupled tearing modes in a tokamak unlock. However, the typical m = 1 mode amplitude below which slinky breakup is triggered is much smaller than that above which slinky formation occurs. Analytic expressions for the slinky formation and breakup thresholds are obtained in all regimes of physical interest. The locking of the slinky mode to a static error-field is also investigated analytically. Either the error-field arrests the rotation of the plasma at the reversal surface before the formation of the slinky mode, so that the mode subsequently forms as a non-rotating mode, or the slinky mode forms as a rotating mode and subsequently locks to the error-field. Analytic expressions for the locking and unlocking thresholds are obtained in all regimes of physical interest. The problems associated with a locked slinky mode can be alleviated by canceling out the accidentally produced error-field responsible for locking the slinky mode, using a deliberately created ''control'' error-field. Alternatively, the locking angle of the slinky mode can be swept toroidally by rotating the control field.

  17. A theoretical investigation of mode-locking phenomena in reversed field pinches

    International Nuclear Information System (INIS)

    Richard Fitzpatrick

    2004-01-01

    OAK-B135 This paper investigates the formation and breakup of the ''slinky mode'' in an RFP using analytic techniques previously employed to examine mode locking phenomena in tokamaks. The slinky mode is a toroidally localized, coherent interference pattern in the magnetic field which co-rotates with the plasma at the reversal surface. This mode forms, as a result of the nonlinear coupling of multiple m = 1 core tearing modes, via a bifurcation which is similar to that by which toroidally coupled tearing modes lock together in a tokamak. The slinky mode breaks up via a second bifurcation which is similar to that by which toroidally coupled tearing modes in a tokamak unlock. However, the typical m = 1 mode amplitude below which slinky breakup is triggered is much smaller than that above which slinky formation occurs. Analytic expressions for the slinky formation and breakup thresholds are obtained in all regimes of physical interest. The locking of the slinky mode to a static error-field is also investigated analytically. Either the error-field arrests the rotation of the plasma at the reversal surface before the formation of the slinky mode, so that the mode subsequently forms as a non-rotating mode, or the slinky mode forms as a rotating mode and subsequently locks to the error-field. Analytic expressions for the locking and unlocking thresholds are obtained in all regimes of physical interest. The problems associated with a locked slinky mode can be alleviated by canceling out the accidentally produced error-field responsible for locking the slinky mode, using a deliberately created ''control'' error-field. Alternatively, the locking angle of the slinky mode can be swept toroidally by rotating the control field

  18. Flow field design for high-pressure PEM electrolysis cells

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Kær, Søren Knudsen

    -water distributes. Water not only serves a reactant, it also aids in cooling due to its high specific heat capacity. The movement of liquid water at the anode is difficult to model, since it is highly coupled to the formation of gas bubbles. To capture the complex two-phase flow behaviour that takes place within...... micro-channels and porous media, our research group has developed an Euler-Euler model in the computational fluid dynamics modelling framework of ANSYS CFX. In addition to two-phase flow, the model accounts for turbulence, species transport in the gas phase, heat transport in all three phases (i.......e. solid, gas and liquid), as well as charge transport of electrons and ions. Our recent improvements have focused on the models ability to account for phase change and electrochemistry as well as the modelling of two-phase flow regimes. For comparison, an interdigitated and parallel channel flow field...

  19. Tokamak-like confinement at high beta and low field in the reversed field pinch

    International Nuclear Information System (INIS)

    Sarff, J S; Anderson, J K; Biewer, T M; Brower, D L; Chapman, B E; Chattopadhyay, P K; Craig, D; Deng, B; Hartog, D J Den; Ding, W X; Fiksel, G; Forest, C B; Goetz, J A; O'Connell, R; Prager, S C; Thomas, M A

    2003-01-01

    For several reasons, improved-confinement achieved in the reversed field pinch (RFP) during the last few years can be characterized as 'tokamak-like'. Historically, RFP plasmas have had relatively poor confinement due to tearing instability which causes magnetic stochasticity and enhanced transport. Tearing reduction is achieved through modification of the inductive current drive, which dramatically improves confinement. The electron temperature increases to >1 keV and the electron heat diffusivity decreases to approx. 5 m 2 s -1 , comparable with the transport level expected in a tokamak plasma of the same size and current. This corresponds to a 10-fold increase in global energy confinement. Runaway electrons are confined, and Fokker-Planck modelling of the electron distribution reveals that the diffusion at high energy is independent of the parallel velocity, uncharacteristic of stochastic transport. Improved-confinement occurs simultaneously with increased beta approx. 15%, while maintaining a magnetic field strength ten times weaker than a comparable tokamak. Measurements of the current, magnetic, and electric field profiles show that a simple Ohm's Law applies to this RFP sustained without dynamo relaxation

  20. Fusion Performance of High Magnetic Field Expe-riments

    Science.gov (United States)

    Airoldi, A.; Cenacchi, G.; Coppi, B.

    1997-11-01

    High magnetic field machines have the characteristic of operating well within the usual limitations known as density and beta limits. This feature is highlighted in the Ignitor concept thanks to its reference field of up to 13 T on the magnetic axis and its high current densities. The two reference scenarios with plasma currents of 12 MA and 11 MA respectively, are discussed. The ramp time is 4 sec for both scenarios, whereas the following programmed time dependence of the current is different. The results of an extensive series of numerical simulations using an appropriate version of the 1+1/2D JETTO transport code show that in any case optimal fusion performances are reacheable without needing enhancement over the values of the energy replacement time predicted by the most pessimistic scalings (for the so-called L-mode regime). The density is the crucial parameter involved on the path to ignition that can be achieved provided the density rise is carefully programmed. The density profiles can be controlled by the proper use of the pellet injector that is included in the machine design.

  1. Development of high temperature superconductors for magnetic field applications

    International Nuclear Information System (INIS)

    Larbalestier, D.C.

    1991-01-01

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbations to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development

  2. High-Energy Physics Outstanding Junior Investigating Program. Summary report

    International Nuclear Information System (INIS)

    Kaplan, David E.

    2009-01-01

    Throughout the past five years I have worked to uncover what physics lies beyond that of the standard model. My main focus in the first two and a half years has been to understand physics at the electroweak scale, and to a lesser extent understand the relationship between particle physics and cosmology. My final two and a half years was spent on studying the feasibility of discovering 'non-standard' models of electroweak physics at hadron colliders, working in close contact with experimentalists at the Tevatron and the LHC. My biggest successes during this period has been both in electroweak physics - expanding our understanding of the Higgs sector in supersymmetric theories and ultraviolet completions of little Higgs theories - and in collider physics - discovering a method for identifying high momentum top quarks and realizing the potential for LHCb to discover some versions of supersymmetry. I have also made some progress towards a particle physics/effective field theory solution of the cosmological constant problem.

  3. Problem-based learning through field investigation: Boosting questioning skill, biological literacy, and academic achievement

    Science.gov (United States)

    Suwono, Hadi; Wibowo, Agung

    2018-01-01

    Biology learning emphasizes problem-based learning as a learning strategy to develop students ability in identifying and solving problems in the surrounding environment. Problem identification skills are closely correlated with questioning skills. By holding this skill, students tend to deliver a procedural question instead of the descriptive one. Problem-based learning through field investigation is an instruction model which directly exposes the students to problems or phenomena that occur in the environment, and then the students design the field investigation activities to solve these problems. The purpose of this research was to describe the improvement of undergraduate biology students on questioning skills, biological literacy, and academic achievement through problem-based learning through field investigation (PBFI) compared with the lecture-based instruction (LBI). This research was a time series quasi-experimental design. The research was conducted on August - December 2015 and involved 26 undergraduate biology students at the State University of Malang on the Freshwater Ecology course. The data were collected during the learning with LBI and PBFI, in which questioning skills, biological literacy, and academic achievement were collected 3 times in each learning model. The data showed that the procedural correlative and causal types of questions are produced by the students to guide them in conducting investigations and problem-solving in PBFI. The biological literacy and academic achievement of the students at PBFI are significantly higher than those at LBI. The results show that PBFI increases the questioning skill, biological literacy, and the academic achievement of undergraduate biology students.

  4. Investigation of Workplace-like Calibration Fields via a Deuterium-Tritium (D-T) Neutron Generator.

    Science.gov (United States)

    Mozhayev, Andrey V; Piper, Roman K; Rathbone, Bruce A; McDonald, Joseph C

    2017-04-01

    Radiation survey meters and personal dosimeters are typically calibrated in reference neutron fields based on conventional radionuclide sources, such as americium-beryllium (Am-Be) or californium-252 (Cf), either unmodified or heavy-water moderated. However, these calibration neutron fields differ significantly from the workplace fields in which most of these survey meters and dosimeters are being used. Although some detectors are designed to yield an approximately dose-equivalent response over a particular neutron energy range, the response of other detectors is highly dependent upon neutron energy. This, in turn, can result in significant over- or underestimation of the intensity of neutron radiation and/or personal dose equivalent determined in the work environment. The use of simulated workplace neutron calibration fields that more closely match those present at the workplace could improve the accuracy of worker, and workplace, neutron dose assessment. This work provides an overview of the neutron fields found around nuclear power reactors and interim spent fuel storage installations based on available data. The feasibility of producing workplace-like calibration fields in an existing calibration facility has been investigated via Monte Carlo simulations. Several moderating assembly configurations, paired with a neutron generator using the deuterium tritium (D-T) fusion reaction, were explored.

  5. Investigation of high-energy-proton effects in aluminum

    International Nuclear Information System (INIS)

    Czajkowski, C.J.; Snead, C.L. Jr.; Todosow, M.

    1997-01-01

    Specimens of 1100 aluminum were exposed to several fluences of 23.5-GeV protons at the Brookhaven Alternating Gradient Synchrotron. Although this energy is above those currently being proposed for spallation-neutron applications, the results can be viewed as indicative of trends and other microstructural evolution with fluence that take place with high-energy proton exposures such as those associated with an increasing ratio of gas generation to dpa. TEM investigation showed significantly larger bubble size and lower density of bubbles compared with lower-energy proton results. Additional testing showed that the tensile strength increased with fluence as expected, but the microhardness decreased, a result for which an intepretation is still under investigation

  6. HEATING CHARACTERISTICS OF SOFTWOODS IN A HIGH FREQUENCY FIELD

    Directory of Open Access Journals (Sweden)

    Ciprian LĂZĂRESCU

    2012-12-01

    Full Text Available The research aimed to establish whetherdielectric heating at radio frequencies might be afeasible option for phytosanitation of green softwoodboards. Results are presented for two softwoodspecies, namely, lodgepole pine (Pinus contorta andwestern red cedar (Thujaplicata Donn., and forsingle-specimen testing configurations with a crosssection of 40x90mm surrounded on three sides bysimilar cross-section kiln dried boards. In terms ofdielectric properties, red cedar is nature "designed" toabsorb more easily the dielectric fields. Heating rateswere not correlated with moisture content for neitherspecies investigated thus underlining the versatility ofRF-heating that allows simultaneous rise oftemperature within dry and wet areas. Convectionlosses through air contact may reduce the averageheating rate of the shell by about 40%.

  7. Hole-phonon scattering in high magnetic fields

    International Nuclear Information System (INIS)

    Singh, Surendra; Verma, G.S.

    1980-01-01

    The relative importance of the elastic and inelastic phonon scatterings by shallow acceptors to the low temperature magneto-phonon conductivity of boron doped silicon has been investigated in the present work. It is shown that in the temoerature range 1-5deg K and for magnetic fields upto 55 KG the elastic scattering makes the major contribution towards phonon resistivity. Magnetic field removes the degenracy of the ground state and the phonon conductivity first falls as the level splittings become comparable to the dominant phonon energies (approximately 4 kBT) and then rises rapidly when the splittings become >> kBT. These features are reflected in the present computations with the new effective g values of the acceptor holes, which are given by gsub(3/2) = 2.33 and gsub(1/2) = 1.00. The discrepancy between theory and experiment regarding the absolute values of the ratio [K(H)/K(H=0)] still remains unresolved with the present magnetic level structure and g values. (author)

  8. Magnetism and high magnetic-field-induced stability of alloy carbides in Fe-based materials.

    Science.gov (United States)

    Hou, T P; Wu, K M; Liu, W M; Peet, M J; Hulme-Smith, C N; Guo, L; Zhuang, L

    2018-02-14

    Understanding the nature of the magnetic-field-induced precipitation behaviors represents a major step forward towards unravelling the real nature of interesting phenomena in Fe-based alloys and especially towards solving the key materials problem for the development of fusion energy. Experimental results indicate that the applied high magnetic field effectively promotes the precipitation of M 23 C 6 carbides. We build an integrated method, which breaks through the limitations of zero temperature and zero external field, to concentrate on the dependence of the stability induced by the magnetic effect, excluding the thermal effect. We investigate the intimate relationship between the external field and the origins of various magnetics structural characteristics, which are derived from the interactions among the various Wyckoff sites of iron atoms, antiparallel spin of chromium and Fe-C bond distances. The high-magnetic-field-induced exchange coupling increases with the strength of the external field, which then causes an increase in the parallel magnetic moment. The stability of the alloy carbide M 23 C 6 is more dependent on external field effects than thermal effects, whereas that of M 2 C, M 3 C and M 7 C 3 is mainly determined by thermal effects.

  9. Site investigations for final disposal of high-level nuclear waste

    International Nuclear Information System (INIS)

    Aeikaes, T.; Laine, T.

    1982-12-01

    Research concerning disposal of high-level nuclear waste of the Industrial Power Company Ltd has focused on deep underground disposal in Finnish precambrian bedrock. The present target is to have a repository for high-level waste in operation by 2020. Selection of the repository site is based on site investigations. In addition to geosciences, selection of appropriate site includes many branches of studies; engineering, safety analysis, ecology, transport, demography etc. The investigations required for site selection for high-level waste have been arranged in a sequence of four phases. The aim of the phases is that investigations become more and more detailed as the selection process continues. Phase I of the investigations is the characterization of potential areas. This comprises establishment of criteria for site selection and identification of areas that meet selection criteria. Objective of these studies is to determine areas for phase II field investigations. The studies are largely made by reviewing existing data and remote-sensing techniques. Phase II field investigations will be undertaken between 1986-1992. The number of potential candidates for repository site is reduced to few preferred areas by preceeding generic study. The site selection process culminates in phase III in site confirmation studies carried out at 2...3 most suitable sites during 1992-2010. This is then followed by phase IV, which comprises very detailed investigations at the selected site. An alternative for these investigations is to undertake them by using pilot shaft and drifts. Active development is taking place in all phases concerning investigation methods, criteria, parameters, data processing and modelling. The applicability of the various investigation methods and techniques is tested in a deep borehole in phase I. The co-operation with countries with similar geological conditions makes it possible to compare results obtained by different techniques

  10. Investigations in high speed blanking: cutting forces and microscopic observations

    Directory of Open Access Journals (Sweden)

    Larue A.

    2010-06-01

    Full Text Available A new hopefull technique, called high speed blanking, has been investigated since few years. To understand the cutting process and how the tools have to be designed, this study is interrested in the cutting force measurement. A new cutting force measurement device has to be designed consider the industrial interest of such a study. The designed test bench induces a calibration process in order to stucy the cutting forces evolution. The paper is discussing the result that the peack load seems to decrease when the punch speed increases. Finally microscopic observations are made in order to find Adiabatic Shear Bands.

  11. High pressure MHD coal combustors investigation, phase 2

    Science.gov (United States)

    Iwata, H.; Hamberg, R.

    1981-05-01

    A high pressure MHD coal combustor was investigated. The purpose was to acquire basic design and support engineering data through systematic combustion experiments at the 10 and 20 thermal megawatt size and to design a 50 MW/sub t/ combustor. This combustor is to produce an electrically conductive plasma generated by the direct combustion of pulverized coal with hot oxygen enriched vitiated air that is seeded with potassium carbonate. Vitiated air and oxygen are used as the oxidizer, however, preheated air will ultimately be used as the oxidizer in coal fired MHD combustors.

  12. Neutron investigations of magnetic properties of crystal substances with use of a pulsed magnetic field

    CERN Document Server

    Nitts, V V

    2001-01-01

    Bases for neutron researches of magnetic properties of crystal substances with use of a pulsed magnetic field and analysis of possible application of various neutron sources in this area are submitted. The review of the most interesting physical results is presented. Main investigations on pulsed reactors of JINR are researches on kinetics of the first order reorientational phase transitions induced in single crystals, and also measurements of antiferromagnetic ordering induced by an external magnetic field. Magnetic phase transitions, induced by a field up to 160 kOe in several magnetic ordering substances, were studied in KEK (Japan). Experiment on observation of spin-flop transition in MnF sub 2 was carried out on TRIGA-reactor in a mode of single flashes of power

  13. Effects of a High Magnetic Field on the Microstructure of Ni-Based Single-Crystal Superalloys During Directional Solidification

    Science.gov (United States)

    Xuan, Weidong; Lan, Jian; Liu, Huan; Li, Chuanjun; Wang, Jiang; Ren, Weili; Zhong, Yunbo; Li, Xi; Ren, Zhongming

    2017-08-01

    High magnetic fields are widely used to improve the microstructure and properties of materials during the solidification process. During the preparation of single-crystal turbine blades, the microstructure of the superalloy is the main factor that determines its mechanical properties. In this work, the effects of a high magnetic field on the microstructure of Ni-based single-crystal superalloys PWA1483 and CMSX-4 during directional solidification were investigated experimentally. The results showed that the magnetic field modified the primary dendrite arm spacing, γ' phase size, and microsegregation of the superalloys. In addition, the size and volume fractions of γ/ γ' eutectic and the microporosity were decreased in a high magnetic field. Analysis of variance (ANOVA) results showed that the effect of a high magnetic field on the microstructure during directional solidification was significant ( p Ni-based single-crystal superalloy blades by applying a high magnetic field.

  14. Monitoring abandoned dreg fields of high-speed railway construction with UAV remote sensing technology

    Science.gov (United States)

    Lin, Jiayuan; Wang, Zhiliang; Wang, Yangchun; Lin, Yi; Du, Xiaolin

    2015-12-01

    High-speed railway construction will produce a large amount of abandoned dregs, so it is necessary to build enough dreg deposition fields along the railway. The task of the department of soil and water conservation is to monitor the construction and usage of abandoned dreg fields according to the design in the whole process of railway construction. As long linear construction projects, many high-speed railways go through regions of complex terrain, which poses great difficulties to monitoring current status of abandoned dreg fields. With the advantages of low cost, flexible launch and landing, safety, under-cloud-flying, hyperspatial image resolution, Unmanned Aerial Vehicles (UAVs) are very suitable for obtaining remote sensing imagery along the railway. One segment of the high-speed railway from Chongqing to Wanzhou and its neighborhood was chosen as the study area to demonstrate key technologies and specific procedures of monitoring abandoned dreg fields using the UAV system. The UAV system and its components are introduced along with the flight trajectories, acquired UAV imagery, and attitude data. Image preprocessing and generation of DEM and DOM are described in detail followed by image-based measurement accuracy assessment and abandoned dreg field status investigation on the resulting DOM and DEM. Results prove the feasibility and effectiveness of applying the fixed wing UAV system to rapidly monitoring the construction and usage of abandoned dreg fields

  15. INVESTIGATION OF PHOTOTRIANGULATION ACCURACY WITH USING OF VARIOUS TECHNIQUES LABORATORY AND FIELD CALIBRATION

    Directory of Open Access Journals (Sweden)

    A. G. Chibunichev

    2016-10-01

    Full Text Available Nowadays, aerial survey technology using aerial systems based on unmanned aerial vehicles (UAVs becomes more popular. UAVs physically can not carry professional aerocameras. Consumer digital cameras are used instead. Such cameras usually have rolling, lamellar or global shutter. Quite often manufacturers and users of such aerial systems do not use camera calibration. In this case self-calibration techniques are used. However such approach is not confirmed by extensive theoretical and practical research. In this paper we compare results of phototriangulation based on laboratory, test-field or self-calibration. For investigations we use Zaoksky test area as an experimental field provided dense network of target and natural control points. Racurs PHOTOMOD and Agisoft PhotoScan software were used in evaluation. The results of investigations, conclusions and practical recommendations are presented in this article.

  16. 77 FR 16850 - Notice of Reclassification of One Investigative Field Office to Regional Office: Denver, CO

    Science.gov (United States)

    2012-03-22

    ...This notice advises the public that the HUD/OIG Office of Investigation plans to reclassify its Denver, Colorado field office as a regional office. The planned reorganization is intended to: 1. Improve the alignment of limited investigative resources, to promote more efficient responses to HUD or Congressional requests involving critical program issues; 2. Redeploy resources to prevent and detect fraud in new program delivery of CPD, FHA and other HUD programs; and 3. Improve management control and effectiveness, and reduce travel costs of management by reducing region size. 4. Return to the traditional Regional alignment of HUD OIG Regional offices and HUD Regional offices.

  17. Investigation of ginkgo biloba leave extracts as corrosion and Oil field microorganism inhibitors.

    Science.gov (United States)

    Chen, Gang; Zhang, Min; Zhao, Jingrui; Zhou, Rui; Meng, Zuchao; Zhang, Jie

    2013-05-07

    Ginkgo biloba (Ginkgoaceae), originating from China, now distributes all over the world. Wide application of Ginkgo biloba extracts is determined by the main active substances, flavonoids and terpenoids, which indicates its extracts suitable to be used as an effective corrosion inhibitor. The extracts of Ginkgo biloba leave have been investigated on the corrosion inhibition of Q235A steel with weight loss and potentiodynamic polarisation techniques. The inhibition efficiency of the extracts varies with extract concentration. The extracts inhibit corrosion mainly by adsorption mechanism. Potentiodynamic polarisation studies show that extracts are mixed type inhibitors. The antibacterial activity of the extracts against oil field microorganism (SRB, IB and TGB) was also investigated.

  18. Investigation of Electromagnetic Field Threat to Fuel Tank Wiring of a Transport Aircraft

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Dudley, Kenneth L.; Scearce, Stephen A.; Beck, Fred B.; Deshpande, Manohar D.; Cockrell, C. R.

    2000-01-01

    National Transportation Safety Board investigators have questioned whether an electrical discharge in the Fuel Quantity Indication System (FQIS) may have initiated the TWA-800 center wing tank explosion. Because the FQIS was designed to be incapable of producing such a discharge on its own, attention has been directed to mechanisms of outside electromagnetic influence. To support the investigation, the NASA Langley Research Center was tasked to study the potential for radiated electromagnetic fields from external radio frequency (RF) transmitters and passenger carried portable electronic devices (PEDs) to excite the FQIS enough to cause arcing, sparking or excessive heating within the fuel tank.

  19. Stress Response to High Magnetic Fields in Transgenic Arabidopsis thaliana Plants.

    Science.gov (United States)

    Morgan, A. N.; Watson, B. C.; Maloney, J. R.; Meisel, M. W.; Brooks, J. S.; Paul, A.-L.; Ferl, R. J.

    2000-03-01

    With increasingly greater strength magnetic fields becoming available in research and medicine, the response of living tissue exposed to high magnetic fields has come under investigation. In this experiment, genetically engineered arabidopsis plants were exposed to homogeneous magnetic fields of varying strengths using a superconducting NMR magnet (0 to 9 T) at UF and a resistive magnet (0 to 25 T) at the NHMFL. The engineered plants produce the enzyme β-glucaronidase (GUS) when under stressful environmental conditions. The level of GUS activity is determined through qualitative histochemical assays and quantitative fluorometric assays. The control group of plants experienced baseline levels of GUS activity, but some of the plants that were exposed to magnetic fields in excess of 9 T show increased stress response. Additional information is available at http://www.phys.ufl.edu/ ~meisel/maglev.htm.

  20. Flux Trapping Properties of Bulk HIGH-TC Superconductors in Static Field-Cooling Magnetization

    Science.gov (United States)

    Deng, Z.; Tsuzuki, K.; Miki, M.; Felder, B.; Hara, S.; Izumi, M.

    2013-06-01

    The trapping process and saturation effect of trapped magnetic flux of bulk high-temperature superconductors by static field-cooling magnetization (FCM) are reported in the paper. With a cryogenic Bell Hall sensor attached on the center of the bulk surface, the synchronous magnetic signals were recorded during the whole magnetization process. It enables us to know the flux trapping behavior since the removal of the excitation field, as well as the subsequent flux relaxation phenomenon and the flux dissipation in the quench process of the bulk sample. With the help of flux mapping techniques, the relationship between the trapped flux and the applied field was further investigated; the saturation effect of trapped flux was discussed by comparing the peak trapped field and total magnetic flux of the bulk sample. These studies are useful to understand the basic flux trapping properties of bulk superconductors.

  1. Investigation of space charge in low-density polyethylene using a field probe technique

    DEFF Research Database (Denmark)

    Khalil, M. Salah; Hansen, Bo Svarrer

    1988-01-01

    A test method that uses a capacitive field probe to investigate the space charge distribution in low-density polyethylene (LDPE) is described. Specimens of 7-mm thickness were stressed under 100 kV DC at room temperature and for different time periods. The results indicate that the LDPE insulation...... layer between electrodes is occupied by positive and negative homocharges. The dependence of space charge distribution on the stressing time is also evident...

  2. Investigation of an innovative technology for oil-field brine treatment

    Energy Technology Data Exchange (ETDEWEB)

    Miskovic, D.; Dalmacija, B.; Hain, Z.; Karlovic, E.; Maric, S.; Uzelac, N. (Inst. of Chemistry, Faculty of Sciences, V. Vlahovica 2 (YU))

    1989-01-01

    Various aspects of an innovative technology for oil field brine treatment were investigated on a laboratory scale. The both free and dispersed oily matter were separated by gravitation and sedimentation. Apart from the physico-chemical oil removal process, special attention was paid to different variants of improved microbiological treatment: dilution with fresh water and application of powdered activated carbon (PAC). Advanced treatment was carried out on granular biological activated carbon (GBAC). A technological scheme for complete treatment was proposed. (author).

  3. High-pressure and temperature investigations of energetic materials

    Science.gov (United States)

    Gump, J. C.

    2014-05-01

    Static high-pressure measurements are extremely useful for obtaining thermodynamic and phase stability information from a wide variety of materials. However, studying energetic materials can be challenging when extracting information from static high-pressure measurements. Energetic materials are traditionally C, H, N, O compounds with low crystalline symmetry, producing weak signal in commonly performed x-ray diffraction measurements. The small sample volume available in a static high-pressure cell exacerbates this issue. Additionally, typical hydrostatic compression media, such as methanol/ethanol, may react with many energetic materials. However, characterization of their thermodynamic parameters and phase stability is critical to understanding explosive performance and sensitivity. Crystalline properties, such as bulk modulus and thermal expansion, are necessary to accurately predict the behaviour of shocked solids using hydrodynamic codes. In order to obtain these values, equations of state of various energetic materials were investigated using synchrotron angle-dispersive x-ray diffraction experiments at static high-pressure and temperature. Intense synchrotron radiation overcomes the weak x-ray scattering of energetic materials in a pressure cell. The samples were hydrostatically compressed using a non-reactive hydrostatic medium and heated using a heated diamond anvil cell. Pressure - volume data for the materials were fit to the Birch-Murnaghan and Vinet formalisms to obtain bulk modulus and its first pressure derivative. Temperature - volume data at ambient pressure were fit to obtain the volume thermal expansion coefficient. Data from several energetic materials will be presented and compared.

  4. Shemya AFB, Alaska 1992 IRP field investigation report. Volume 1: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The US Air Force is currently investigating 22 sites on Shemya Air Force Base (AFB) to determine if past spill and disposal activities have caused environmental damage. These investigations are being carried out under the Air Force`s Installation Restoration Program (IRP). As a part of the IRP program, field investigations were performed in 1992 to obtain the information needed to assess what future actions willneed to be carried out at each site. The island`s drinking water supply was also investigated. Activities completed at 10 selected sites during the 1992 field investigation included surface sampling to determine the lateral extent of contamination, subsurface sampling to determine the vertical extent of contamination, and the installation of well points and monitoring wells to determine the direction of groundwater flow and if the groundwater has been affected by a site. In addition, geophysical surveys were performed at most sites to identify site boundaries and check for the presence of buried metal to be avoided during drilling activities.

  5. Integrative field scale phenotyping for investigating metabolic components of water stress within a vineyard

    Directory of Open Access Journals (Sweden)

    Jorge Gago

    2017-10-01

    Full Text Available Abstract Background There is currently a high requirement for field phenotyping methodologies/technologies to determine quantitative traits related to crop yield and plant stress responses under field conditions. Methods We employed an unmanned aerial vehicle equipped with a thermal camera as a high-throughput phenotyping platform to obtain canopy level data of the vines under three irrigation treatments. High-resolution imagery (< 2.5 cm/pixel was employed to estimate the canopy conductance (g c via the leaf energy balance model. In parallel, physiological stress measurements at leaf and stem level as well as leaf sampling for primary and secondary metabolome analysis were performed. Results Aerial g c correlated significantly with leaf stomatal conductance (g s and stem sap flow, benchmarking the quality of our remote sensing technique. Metabolome profiles were subsequently linked with g c and g s via partial least square modelling. By this approach malate and flavonols, which have previously been implicated to play a role in stomatal function under controlled greenhouse conditions within model species, were demonstrated to also be relevant in field conditions. Conclusions We propose an integrative methodology combining metabolomics, organ-level physiology and UAV-based remote sensing of the whole canopy responses to water stress within a vineyard. Finally, we discuss the general utility of this integrative methodology for broad field phenotyping.

  6. Fast and Simple Detection of Yersinia pestis Applicable to Field Investigation of Plague Foci

    Science.gov (United States)

    Simon, Stéphanie; Demeure, Christian; Lamourette, Patricia; Filali, Sofia; Plaisance, Marc; Créminon, Christophe; Volland, Hervé; Carniel, Elisabeth

    2013-01-01

    Yersinia pestis, the plague bacillus, has a rodent-flea-rodent life cycle but can also persist in the environment for various periods of time. There is now a convenient and effective test (F1-dipstick) for the rapid identification of Y. pestis from human patient or rodent samples, but this test cannot be applied to environmental or flea materials because the F1 capsule is mostly produced at 37°C. The plasminogen activator (PLA), a key virulence factor encoded by a Y. pestis-specific plasmid, is synthesized both at 20°C and 37°C, making it a good candidate antigen for environmental detection of Y. pestis by immunological methods. A recombinant PLA protein from Y. pestis synthesized by an Escherichia coli strain was used to produce monoclonal antibodies (mAbs). PLA-specific mAbs devoid of cross-reactions with other homologous proteins were further cloned. A pair of mAbs was selected based on its specificity, sensitivity, comprehensiveness, and ability to react with Y. pestis strains grown at different temperatures. These antibodies were used to develop a highly sensitive one-step PLA-enzyme immunoassay (PLA-EIA) and an immunostrip (PLA-dipstick), usable as a rapid test under field conditions. These two PLA-immunometric tests could be valuable, in addition to the F1-disptick, to confirm human plague diagnosis in non-endemic areas (WHO standard case definition). They have the supplementary advantage of allowing a rapid and easy detection of Y. pestis in environmental and flea samples, and would therefore be of great value for surveillance and epidemiological investigations of plague foci. Finally, they will be able to detect natural or genetically engineered F1-negative Y. pestis strains in human patients and environmental samples. PMID:23383008

  7. Dynamics of Coulomb correlations in semiconductors in high magnetic fields

    International Nuclear Information System (INIS)

    Fromer, Neil Alan

    2002-01-01

    Current theories have been successful in explaining many nonlinear optical experiments in undoped semiconductors. However, these theories require a ground state which is assumed to be uncorrelated. Strongly correlated systems of current interest, such as a two dimensional electron gas in a high magnetic field, cannot be explained in this manner because the correlations in the ground state and the low energy collective excitations cause a breakdown of the conventional techniques. We perform ultrafast time-resolved four-wave mixing on $n$-modulation doped quantum wells, which contain a quasi-two dimensional electron gas, in a large magnetic field, when only a single Landau level is excited and also when two levels are excited together. We find evidence for memory effects and as strong coupling between the Landau levels induced by the electron gas. We compare our results with simulations based on a new microscopic approach capable of treating the collective effects and correlations of the doped electrons, and find a good qualitative agreement. By looking at the individual contributions to the model, we determine that the unusual correlation effects seen in the experiments are caused by the scattering of photo-excited electron-hole pairs with the electron gas, leading to new excited states which are not present in undoped semiconductors, and also by exciton-exciton interactions mediated by the long-lived collective excitations of the electron gas, inter-Landau level magnetoplasmons

  8. The optimal use of contrast agents at high field MRI

    International Nuclear Information System (INIS)

    Trattnig, Siegfried; Pinker, Kathia; Ba-Ssalamah, Ahmed; Noebauer-Huhmann, Iris-Melanie

    2006-01-01

    The intravenous administration of a standard dose of conventional gadolinium-based contrast agents produces higher contrast between the tumor and normal brain at 3.0 Tesla (T) than at 1.5 T, which allows reducing the dose to half of the standard one to produce similar contrast at 3.0 T compared to 1.5 T. The assessment of cumulative triple-dose 3.0 T images obtained the best results in the detection of brain metastases compared to other sequences. The contrast agent dose for dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging at 3.0 T can be reduced to 0.1 mmol compared to 0.2 mmol at 1.5 T due to the increased susceptibility effects at higher magnetic field strengths. Contrast agent application makes susceptibility-weighted imaging (SWI) at 3.0 T clinically attractive, with an increase in spatial resolution within the same scan time. Whereas a double dose of conventional gadolinium-based contrast agents was optimal in SWI with respect to sensitivity and image quality, a standard dose of gadobenate dimeglumine, which has a two-fold higher T1-relaxivity in blood, produced the same effect. For MR-arthrography, optimized concentrations of gadolinium-based contrast agents are similar at 3.0 and 1.5 T. In summary, high field MRI requires the optimization of the contrast agent dose in different clinical applications. (orig.)

  9. Storage of high-level wastes, investigations in underground laboratories

    International Nuclear Information System (INIS)

    Ouzounian, G.

    1999-01-01

    This article reviews the different collaborations made by ANDRA (national agency for the management of radioactive wastes) in the fields of underground radioactive waste storage. ANDRA has taken part in various experimental research programs performed in laboratories such as Mol in Belgium, Aspo in Sweden, Pinawa in Canada and Grimsel in Switzerland. This article details the experiments led at Mol since 1984. ANDRA is commissioned by the 30.12.91 decree to study the possibility of storage in deep geological layers. A thorough knowledge of the matter requires the building of underground laboratories in order to test and validate technological choices on a real scale. 6 themes will have to be investigated: 1) the capacity to seal up the storage facility after its use in order to assure the protection of man and environment, 2) the effects of geological perturbations on the confining properties of the site, 3) the confining ability of the Callovian-Oxfordian geological formation, 4) the transfer of radionuclides from the geological formation to the biosphere, 5) the constructing possibility of an underground storage facility, and 6) the possibility of retrieving the stored packages. (A.C.)

  10. High resolution flow field prediction for tail rotor aeroacoustics

    Science.gov (United States)

    Quackenbush, Todd R.; Bliss, Donald B.

    The prediction of tail rotor noise due to the impingement of the main rotor wake poses a significant challenge to current analysis methods in rotorcraft aeroacoustics. This paper describes the development of a new treatment of the tail rotor aerodynamic environment that permits highly accurate resolution of the incident flow field with modest computational effort relative to alternative models. The new approach incorporates an advanced full-span free wake model of the main rotor in a scheme which reconstructs high-resolution flow solutions from preliminary, computationally inexpensive simulations with coarse resolution. The heart of the approach is a novel method for using local velocity correction terms to capture the steep velocity gradients characteristic of the vortex-dominated incident flow. Sample calculations have been undertaken to examine the principal types of interactions between the tail rotor and the main rotor wake and to examine the performance of the new method. The results of these sample problems confirm the success of this approach in capturing the high-resolution flows necessary for analysis of rotor-wake/rotor interactions with dramatically reduced computational cost. Computations of radiated sound are also carried out that explore the role of various portions of the main rotor wake in generating tail rotor noise.

  11. High-field MR imaging of spinal cord multiple sclerosis

    International Nuclear Information System (INIS)

    De La Paz, R.L.; Floris, R.; Norman, D.; Enzmann, D.R.

    1987-01-01

    Fifty-one high-field MR imaging studies (1.5 T, General Electric Signa) of the spinal cord were performed in 42 patients (27 female, 15 male; mean age, 40 years) with clinically definitive (n = 34) or probable (n = 8) multiple sclerosis and suspected spinal cord lesions. MR imaging showed focal spinal cord abnormalities in 38 (75%) of 51 studies. T2-weighted images were abnormal (showing foci of high signal intensity) in 38 studies, T1-weighted images were abnormal (showing areas of low signal intensity or mass effect) in 16 (42%) of 38, and GRASS images were abnormal (showing foci of high signal intensity) in 9 (82%) of 11 cases. Brain MR imaging showed periventricular lesions typical of multiple sclerosis in 34 (81%) of 42 studies. Spinal cord studies were positive in eight cases with normal brain MR images, and brain studies were positive in 13 instances of normal spinal cord MR images. Four lesions were at the cervicomedullary junction, 44 in the cervical spinal cord, and three in the thoracic cord. Mass effect in cord lesions, simulating neoplasm, was seen in seven patients during the acute symptomatic phase. Serial studies in three patients with decreasing symptoms showed a reduction after 3-4 weeks and resolution of the mass effect after 2-6 months

  12. The CHARIS High-Contrast Integral-Field Spectrograph

    Science.gov (United States)

    Groff, Tyler D.; Chilcote, Jeffrey; Brandt, Timothy; Kasdin, N. Jeremy; Galvin, Michael; Loomis, Craig; Rizzo, Maxime; Knapp, Gillian; Guyon, Olivier; Jovanovic, Nemanja; hide

    2017-01-01

    One of the leading direct Imaging techniques, particularly in ground-based imaging, uses a coronagraphic system and integral field spectrograph (IFS). The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) is an IFS that has been built for the Subaru telescope. CHARIS has been delivered to the observatory and now sits behind the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. CHARIS has 'high' and 'low' resolution operating modes. The "high-resolution" mode is used to characterize targets in J, H, and K bands at R70. The "low-resolution" prism is meant for discovery and spans J+H+K bands (1.15-2.37 microns) with a spectral resolution of R18. This discovery mode has already proven better than 15-sigma detections of HR8799c,d,e when combining ADI+SDI. Using SDI alone, planets c and d have been detected in a single 24 second image. The CHARIS team is optimizing instrument performance and refining ADI+SDI recombination to maximize our contrast detection limit. In addition to the new observing modes, CHARIS has demonstrated a design with high robustness to spectral crosstalk. CHARIS is in the final stages of commissioning, with the instrument open for science observations beginning February 2017. Here we review the science case, design, on-sky performance, engineering observations of exoplanet and disk targets, and specific lessons learned for extremely high contrast imagers. Key design aspects that will be demonstrated are crosstalk optimization, wavefront correction using the IFS image, lenslet tolerancing, the required spectral resolution to fit exoplanet atmospheres, and the utility of the spectrum in achieving higher contrast detection limits.

  13. High-resolution optical telescope for ultraviolet /UV/ radiation field

    Science.gov (United States)

    Karayan, W. W.

    1979-01-01

    Design techniques are discussed for all-reflecting optics from first-order system considerations and applications currently utilized in the field of astronomical optics. The solution of the Dall-Karkham design problem is described, showing the advantage of inexpensive construction as compared with higher order surfaces. The design process reported here is a F/5 collecting system which quickly mates directly with the spectrometer; it is capable of achieving desired high resolution and sensitivity requirements. The theoretical limit of aberration tolerances is achieved with less than 1/8 of a wavelength at final focus (OPD). The design of spectrometer for ultra-violet (UV) radiation and its mechanism is included in this study.

  14. High-Speed and Wide-Field Photometry with TORTORA

    Directory of Open Access Journals (Sweden)

    G. Greco

    2010-01-01

    Full Text Available We present the photometric analysis of the extended sky fields observed by the TORTORA optical monitoring system. The technology involved in the TORTORA camera is based on the use of a fast TV-CCD matrix with an image intensifier. This approach can both significantly reduce the readout noise and shorten the focal length following to monitor relatively large sky regions with high temporal resolution and adequate detection limit. The performance of the system has been tested using the relative magnitudes of standard stars by means of long image sequences collected at different airmasses and at various intensities of the moon illumination. As expected from the previous laboratory measurements, artifact sources are negligible and do not affect the photometric results. The following analysis is based on a large sample of images acquired by the TORTORA instrument since July 2006.

  15. Developments at the High Field Magnet Laboratory in Nijmegen

    Science.gov (United States)

    Perenboom, J. A. A. J.; Maan, J. C.; van Breukelen, M. R.; Wiegers, S. A. J.; den Ouden, A.; Wulffers, C. A.; van der Zande, W. J.; Jongma, R. T.; van der Meer, A. F. G.; Redlich, B.

    2013-03-01

    The High Field Magnet Laboratory at the Radboud University Nijmegen is rapidly expanding its capabilities. The developments encompass both organizational changes and new possibilities for research. The organization of the HFML was strengthened as a consequence of stronger participation of the Foundation for Fundamental Research on Matter (FOM), and an increase of the core-funding. This change makes that HFML is now considered on a national level as large research facility that operates at an international scale. At the same time work is underway to build new and powerful magnets, and provide electromagnetic radiation for magneto-spectroscopic studies. Electromagnetic radiation in the infrared and far-infrared spectrum will soon be available in the HFML with wavelengths between 3 μm and 1.5 mm, produced by the `FELIX' facility, comprising the long-wavelength free electron laser `FLARE' that in September 2011 produced its first light and the free electron lasers that have been moved from Rijnhuizen to Nijmegen. In magnet technology great strides are made to make magnets available for the user community with unprecedented performance: late in 2012 we hope to commission a new all-resistive magnet system that will generate a steady magnetic field as high as 38 T, by fully exploiting the maximum power of the installation, i.e. 20 MW, and using all available improvements in the design and construction of `Florida-Bitter' resistive magnets. We are also well underway with the design of a 45 T hybrid magnet system, using Nb3Sn superconductors and wind-and-react Cable-in-Conduit technology.

  16. Initial studies of high latitude magnetic field data during different magnetospheric conditions

    Science.gov (United States)

    Cersosimo, D. O.; Wanliss, J. A.

    2007-01-01

    We investigate the statistical properties of high-latitude magnetometer data for differing geomagnetic activity. This is achieved by characterizing changes in the nonlinear statistics of the geomagnetic field, by means of the Hurst exponent, measured from a single ground-based magnetometer station. The long-range statistical nature of the geomagnetic field at a local observation site can be described as a multifractional Brownian motion, thus suggesting the statistical structure required of mathematical models of magnetospheric activity. We also find that, in general, the average Hurst exponent for quiet magnetospheric intervals is smaller than that for more active intervals.

  17. Geophysical investigations of well fields to characterize fractured-bedrock aquifers in southern New Hampshire

    Science.gov (United States)

    Degnan, James R.; Moore, Richard Bridge; Mack, Thomas J.

    2001-01-01

    Bedrock-fracture zones near high-yield bedrock wells in southern New Hampshire well fields were located and characterized using seven surface and six borehole geophysical survey methods. Detailed surveys of six sites with various methods provide an opportunity to integrate and compare survey results. Borehole geophysical surveys were conducted at three of the sites to confirm subsurface features. Hydrogeologic settings, including a variety of bedrock and surface geologic materials, were sought to gain an insight into the usefulness of the methods in varied terrains. Results from 15 survey lines, 8 arrays, and 3 boreholes were processed and interpreted from the 6 sites. The surface geophysical methods used provided physical properties of fractured bedrock. Seismic refraction and ground-penetrating radar (GPR) primarily were used to characterize the overburden materials, but in a few cases indicated bedrock-fracture zones. Magnetometer surveys were used to obtain background information about the bedrock to compare with other results, and to search for magnetic lows, which may result from weathered fractured rock. Electromagnetic terrain conductivity surveys (EM) and very-low-frequency electromagnetic surveys (VLF) were used as rapid reconnaissance techniques with the primary purpose of identifying electrical anomalies, indicating potential fracture zones in bedrock. Direct-current (dc) resistivity methods were used to gather detailed subsurface information about fracture depth and orientation. Two-dimensional (2-D) dc-resistivity surveys using dipole-dipole and Schlumberger arrays located and characterized the overburden, bedrock, and bedrock-fracture zones through analysis of data inversions. Azimuthal square array dc-resistivity survey results indicated orientations of conductive steep-dipping bedrock-fracture zones that were located and characterized by previously applied geophysical methods. Various available data sets were used for site selection

  18. Investigation of the high mass Drell Yan spectrum with ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Thomas A.

    2010-09-14

    The Large Hadron Collider started data taking at the end of 2009 and an integrated luminosity of 1fb{sup -1} is hoped for by the end of 2011. A precise measurement of the high mass Drell Yan spectrum offers a good opportunity for a model independent search for new physics. The muon channel is well suited for this, due to the clean signature and the good muon identification in the Muon Spectrometer. Previous studies at high dimuon masses neglected all background contributions. This study investigated the impact of background on the Drell Yan spectrum and it was found that t anti t decays are the most important contribution. Various selection cuts to suppress those background contributions were studied. A method to take systematic uncertainties into account, whilst optimising these selection cuts, has been developed. It was shown that two additional selection cuts based on b-tagging and Missing Transverse Energy (E{sub T}) will reduce the overall uncertainty for a bin from 200 GeV to 300 GeV from 19.1% to 17.2% for an integrated luminosity of 50 pb{sup -1}. An important aspect of this analysis is to ensure that the efficiency for all selection cuts remains stable at very high dimuon masses of up to 1 TeV. This is not the case for the conventional missing E{sub T}, so a derived variable has been introduced and tested. (orig.)

  19. Investigation of a high voltage hollow cathode electron beam source

    International Nuclear Information System (INIS)

    Hansen, Johnny.

    1977-04-01

    An investigation is presented of the possibility of developing an electron accelerator comprising several radiation units with a relatively low power per unit, and without the many elements such as accelerator tube, focusing and scanning systems. A study was desired of an electron gun operated at 200 kV vased on the cold, hollow-cathode principle, where problems concentrated on the design of an electrode configuration that could withstand the high voltage at a pressure where a plasma could be generated too. Studies concentrated on the high voltage breakdown criterion in the pressure range 10 -3 to 10 -2 torr and on the plasma formation in a low pressure gas discharge. Controlled beams with energies up to 130 keV were generated in nitrogen at a pressure of 2 x 10 -3 torr with a beam current of about 1 mA in a continuous operation. The high voltage was limited by the existing power supply in the laboratory; however, a decision was taken not to purchase a power supply that could have delivered the required voltage. (author)

  20. Investigation of the high mass Drell Yan spectrum with ATLAS

    International Nuclear Information System (INIS)

    Mueller, Thomas A.

    2010-01-01

    The Large Hadron Collider started data taking at the end of 2009 and an integrated luminosity of 1fb -1 is hoped for by the end of 2011. A precise measurement of the high mass Drell Yan spectrum offers a good opportunity for a model independent search for new physics. The muon channel is well suited for this, due to the clean signature and the good muon identification in the Muon Spectrometer. Previous studies at high dimuon masses neglected all background contributions. This study investigated the impact of background on the Drell Yan spectrum and it was found that t anti t decays are the most important contribution. Various selection cuts to suppress those background contributions were studied. A method to take systematic uncertainties into account, whilst optimising these selection cuts, has been developed. It was shown that two additional selection cuts based on b-tagging and Missing Transverse Energy (E T ) will reduce the overall uncertainty for a bin from 200 GeV to 300 GeV from 19.1% to 17.2% for an integrated luminosity of 50 pb -1 . An important aspect of this analysis is to ensure that the efficiency for all selection cuts remains stable at very high dimuon masses of up to 1 TeV. This is not the case for the conventional missing E T , so a derived variable has been introduced and tested. (orig.)

  1. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

  2. Spin polarization in high density quark matter under a strong external magnetic field

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; Da Providência, João; Providência, Constança

    2016-01-01

    In high density quark matter under a strong external magnetic field, possible phases are investigated by using the two-flavor Nambu-Jona-Lasinio (NJL) model with tensor-type four-point interaction between quarks, as well as the axial-vector-type four-point interaction. In the tensor-type interact......In high density quark matter under a strong external magnetic field, possible phases are investigated by using the two-flavor Nambu-Jona-Lasinio (NJL) model with tensor-type four-point interaction between quarks, as well as the axial-vector-type four-point interaction. In the tensor...... phase appears in the wide range of the quark chemical potential. In both the interactions, the quark mass in zero and small chemical potential regions increases which indicates that the chiral symmetry breaking is enhanced, namely the magnetic catalysis occurs....

  3. Electric field tuned MoS2/metal interface for hydrogen evolution catalyst from first-principles investigations

    Science.gov (United States)

    Ling, F. L.; Zhou, T. W.; Liu, X. Q.; Kang, W.; Zeng, W.; Zhang, Y. X.; Fang, L.; Lu, Y.; Zhou, M.

    2018-01-01

    Understanding the interfacial properties of catalyst/substrate is crucial for the design of high-performance catalyst for important chemical reactions. Recent years have witnessed a surge of research in utilizing MoS2 as a promising electro-catalyst for hydrogen production, and field effect has been employed to enhance the activity (Wang et al 2017 Adv. Mater. 29, 1604464; Yan et al 2017 Nano Lett. 17, 4109-15). However, the underlying atomic mechanism remains unclear. In this paper, by using the prototype MoS2/Au system as a probe, we investigate effects of external electric field on the interfacial electronic structures via density functional theory (DFT) based first-principles calculations. Our results reveal that although there is no covalent interaction between MoS2 overlayer and Au substrate, an applied electric field efficiently adjusts the charge transfer between MoS2 and Au, leading to tunable Schottky barrier type (n-type to p-type) and decrease of barrier height to facilitate charge injection. Furthermore, we predict that the adsorption energy of atomic hydrogen on MoS2/Au to be readily controlled by electric field to a broad range within a modest magnitude of field, which may benefit the performance enhancement of hydrogen evolution reaction. Our DFT results provide valuable insight into the experimental observations and pave the way for future understanding and control of catalysts in practice, such as those with vacancies, defects, edge states or synthesized nanostructures.

  4. Electric field tuned MoS2/metal interface for hydrogen evolution catalyst from first-principles investigations.

    Science.gov (United States)

    Ling, Faling; Zhou, Tingwei; Liu, Xiaoqing; Kang, Wei; Zeng, Wen; Zhang, Yixin; Fang, L; Lu, Yi; Zhou, Miao

    2017-12-01

    Understanding the interfacial properties of catalyst/substrate is crucial for the design of high-performance catalyst for important chemical reactions. Recent years have witnessed a surge of research in utilizing MoS2 as a promising electro-catalyst for hydrogen production, and field effect has been employed to enhance the activity (Adv. Mater. 2017, 29, 1604464; Nano Lett. 2017, 17, 4109). However, the underlying atomic mechanism remains unclear. In this paper, by using the prototype MoS2/Au system as a probe, we investigate effects of external electric field on the interfacial electronic structures via density functional theory (DFT) based first-principles calculations. Our results reveal that although there is no covalent interaction between MoS2 overlayer and Au substrate, an applied electric field efficiently adjusts the charge transfer between MoS2 and Au, leading to tunable Schottky barrier type (n-type to p-type) and decrease of barrier height to facilitate charge injection. Furthermore, we predict that the adsorption energy of atomic hydrogen on MoS2/Au to be readily controlled by electric field to a broad range within a modest magnitude of field, which may benefit the performance enhancement of hydrogen evolution reaction. Our DFT results provide valuable insight into the experimental observations and pave the way for future understanding and control of catalysts in practice, such as those with vacancies, defects, edge states or synthesized nanostructures. © 2017 IOP Publishing Ltd.

  5. Investigations of some rock stress measuring techniques and the stress field in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Hanssen, Tor Harald

    1997-12-31

    Rock stresses are important to the safe construction and operation of all man-made structures in rock, whether In mining, civil or petroleum engineering. The crucial issue is their relative magnitude and orientation. This thesis develops equipment and methods for further rock stress assessment and reevaluates existing overcoring rock stress measurements, and relates this information to the present geological setting. Both laboratory work and field work are involved. In the field, rock stresses are measured by the overcoring and the hydraulic fracturing technique. An observation technique for assessing likely high stresses is developed. The field data refer to several hydropower projects and to some offshore hydrocarbon fields. The principal sections are: (1) Tectonic setting in the western Fennoscandia, (2) Triaxial rock stress measurements by overcoring using the NTH cell (a strain gauge cell developed at the Norwegian technical university in Trondheim and based on the CSIR cell of the South African Council for Scientific and Industrial Research), (3) Laboratory testing of the NTH cell, (4) Quality ranking of stresses measured by the NTH cell, (4) Recalculated rock stresses and implications to the regional stress field, (5) Hydraulic fracturing stress measurements. 113 refs., 98 figs., 62 tabs.

  6. Investigation of the 4D composite MR image distortion field associated with tumor motion for MR-guided radiotherapy.

    Science.gov (United States)

    Stanescu, T; Jaffray, D

    2016-03-01

    perturbations as it moves further away from the MR isocenter. For a mobile lung tumor, the 4D composite field, corresponding to a 1.5 T field and a readout gradient of 5 mT/m, amounts to 3.0 and 2.8 mm for the MRIgRT system designs featuring B0 oriented along the z-axis (cylindrical-bore scanner) and in the (x,y)-plane (biplanar scanner), respectively. For a rotating biplanar scanner, the composite distortion field varied nonlinearly with the rotation angle. Overall, the dominant contribution to the composite field was from the system-related distortion field. The tumor centroid experienced a systematic shift of 2 mm and showed a negligible perturbation for different B0 values. The dependency on the tumor size was also investigated, namely the max values varied from 1.2 to 2.5 mm for spherical volumes with a diameter between 4 and 80 mm. The composite distortion field requires adequate quantification for lung radiation therapy applications such as treatment planning, pretreatment patient setup verification, and real-time treatment delivery guidance. For certain scenarios such as small tumor volumes, the spatial distortions may be corrected by applying systematic shifts derived from a single tumor motion phase. In the case of high readout gradients common to fast imaging applications, the χ distortions were found to be less than 1 mm irrespective of scanner configuration.

  7. An investigation on image of nuclear energy from the view of Japanese high school students

    International Nuclear Information System (INIS)

    Takahashi, Reiko; Nakayama, Kazuhiko.

    1996-01-01

    The authors have conducted an investigation on Japanese high school students' knowledge, recognition and interest on energy issues. How they are currently recognizing the 'Nuclear Energy' and whether there is a difference in the way of recognition with their attributes have been revealed in this investigation. A questionnaire based on a word association (WA) method and a cluster analysis have been carried out. Using these statistical methodologies, a picture of energy issues from the view of young generations has been cleared. The authors believe that the analysis in the field of nuclear energy by means of such techniques has been done for the first time in Japan. (author)

  8. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    OpenAIRE

    Irena Jeličić; Katarina Lisak; Rajka Božanić

    2012-01-01

    High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF) belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. ...

  9. Combined effects of extremely high frequency electromagnetic field and antibiotics on Enterococcus Hirae growth and survival

    International Nuclear Information System (INIS)

    Ohanyan, V.A.

    2012-01-01

    Combined effects of extremely high frequency electromagnetic field and antibiotics on Enterococcus hirae ATCC 9790 bacterial growth and survival were investigated using 51.8 GHz and 53 GHz frequencies in combination with two commonly used antibiotics: ampicillin and dalacin. Results revealed that, despite bacterial type and membrane structure and properties, the combined effect, especially with 53 GHz and dalacin, suppresses bacterial growth and decreases their survival

  10. [Investigation on sleep status of college and high school students].

    Science.gov (United States)

    Chen, Wei; Shen, Yue-di; Chen, Rong; Ding, Guo-xian

    2005-01-01

    To investigate the sleep status of college and high schools students. Pittsburgh sleep quality index (PSQI) and self-manufactured questionnaires about siesta habits were used as tools. Three groups of students from medical college (MC), senior high school (SS) and junior high school (JS) were surveyed. In the group MC, SS and JS, the occurrence rates of sleep disorders were 27%, 62% and 54%, respectively, and in which the appearance rates of insomnia were 17%, 19% and 19%, longing for sleep were 10%, 43% and 35% respectively. And there were no significant difference between schoolboy and schoolgirl. The occurrence rates of slack breathing were different (5/155, 1/154) significantly between group SS and JS. The distinct differences also were found in group JS and MC, in which students felt hot (10/155, 1/122) and in all the three groups, in which students felt sleepy (55/155, 62/154, 13/122) whereas the difference of sleepy between group SS and JS was comparatively distinct (55/155, 62/154). Significant differences were also found between group JS and SS, MC in average sleep time of (7.65 +/- 0.87) hours, (7.16 +/- 0.83) hours, and (7.10 +/- 0.57) hours. The time of falling asleep (median 15 min, 10 min, 20 min) and siesta habit (8/155, 19/154, 75/122) among group MC and SS, JS were different respectively and markedly, whereas siesta habit differences between group SS and JS were comparatively distinct (8/155, 19/154). Students in high school showed higher rate of longing for sleep, and this implicated they fall short of sleep time greatly and siesta could improve their sleepy signs.

  11. ADX: a high field, high power density, Advanced Divertor test eXperiment

    Science.gov (United States)

    Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Shiraiwa, S.; Terry, J.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; ADX Team

    2014-10-01

    The MIT PSFC and collaborators are proposing an advanced divertor experiment (ADX) - a tokamak specifically designed to address critical gaps in the world fusion research program on the pathway to FNSF/DEMO. This high field (6.5 tesla, 1.5 MA), high power density (P/S ~ 1.5 MW/m2) facility would utilize Alcator magnet technology to test innovative divertor concepts for next-step DT fusion devices (FNSF, DEMO) at reactor-level boundary plasma pressures and parallel heat flux densities while producing high performance core plasma conditions. The experimental platform would also test advanced lower hybrid current drive (LHCD) and ion-cyclotron range of frequency (ICRF) actuators and wave physics at the plasma densities and magnetic field strengths of a DEMO, with the unique ability to deploy launcher structures both on the low-magnetic-field side and the high-field side - a location where energetic plasma-material interactions can be controlled and wave physics is most favorable for efficient current drive, heating and flow drive. This innovative experiment would perform plasma science and technology R&D necessary to inform the conceptual development and accelerate the readiness-for-deployment of FNSF/DEMO - in a timely manner, on a cost-effective research platform. Supported by DE-FC02-99ER54512.

  12. The ongoing investigation of high performance parallel computing in HEP

    CERN Document Server

    Peach, Kenneth J; Böck, R K; Dobinson, Robert W; Hansroul, M; Norton, Alan Robert; Willers, Ian Malcolm; Baud, J P; Carminati, F; Gagliardi, F; McIntosh, E; Metcalf, M; Robertson, L; CERN. Geneva. Detector Research and Development Committee

    1993-01-01

    Past and current exploitation of parallel computing in High Energy Physics is summarized and a list of R & D projects in this area is presented. The applicability of new parallel hardware and software to physics problems is investigated, in the light of the requirements for computing power of LHC experiments and the current trends in the computer industry. Four main themes are discussed (possibilities for a finer grain of parallelism; fine-grain communication mechanism; usable parallel programming environment; different programming models and architectures, using standard commercial products). Parallel computing technology is potentially of interest for offline and vital for real time applications in LHC. A substantial investment in applications development and evaluation of state of the art hardware and software products is needed. A solid development environment is required at an early stage, before mainline LHC program development begins.

  13. High-level radioactive-waste-disposal investigations in Texas

    International Nuclear Information System (INIS)

    Smith, R.D.

    1983-01-01

    The Texas Energy and Natural Resources Advisory Council (TENRAC) was designated in 1980 to coordinate the interaction between the State of Texas and the federal government relating to the high-level radioactive waste disposal issue. This report was prepared to summarize the many aspects of that issue with particular emphasis on the activities in Texas. The report is intended to provide a comprehensive introduction for individuals with little or no previous exposure to the issue and to provide a broader perspective for those individuals who have addressed specific aspects of the issue but have not had the opportunity to study it in a broader context. Following the introduction, contents of this report are as follows: (1) general status of major repository siting investigations in the US; (2) detailed review of Texas studies; (3) possible facilities to be sited in Texas; (4) current Texas policy; (5) federal regulations; and (6) federal legislation. 9 figures, 2 tables

  14. Investigation of Rare Particle Production in High Energy Nuclear Collisions

    International Nuclear Information System (INIS)

    Crawford, Henry J.; Engelage, Jon M.

    1999-01-01

    Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year

  15. The influence of conductivities consistent with field-aligned currents on high-latitude convection patterns

    International Nuclear Information System (INIS)

    Blomberg, L.G.; Marklund, G.T.

    1988-02-01

    The influence on the high-latitude ionospheric convection of conductivities associated with upward field-aligned currents is investigated. Potential patterns are calculated from a given distribution of field-aligned currents and a conductivity model. The resulting patterns are shown to be modified considerably by including a coupling term between the conductivity and the field-aligned current in the conductivity model. The clockwise rotation of the entire potential pattern is reduced when the conductivity enhancement coincides with the regions of upward field-aligned current. Also, the electric field within these regions turns out to be rather insensitive to change in the magnitude of the current. In regions of downward current or when the current-dependent conductivity is excluded there is on the other hand an almost linear relationship between current and electric field. Although the particles producing the conductivity enhancement may not be the same as those carrying the major part of the field-aligned current it is clear from observations that there is a positive correlation between upward current conductivity. Therefore, the simple relationship used in this study is believed to reflect rather well the principal features of the current-conductivity coupling, which is of im- portance to the modelling of ionospheric electrodynamics. (With 26 refs.) (authors)

  16. Self-interacting scalar fields at high-temperature

    Energy Technology Data Exchange (ETDEWEB)

    Deur, Alexandre [University of Virginia, Charlottesville, VA (United States)

    2017-06-15

    We study two self-interacting scalar field theories in their high-temperature limit using path integrals on a lattice. We first discuss the formalism and recover known potentials to validate the method. We then discuss how these theories can model, in the high-temperature limit, the strong interaction and General Relativity. For the strong interaction, the model recovers the known phenomenology of the nearly static regime of heavy quarkonia. The model also exposes a possible origin for the emergence of the confinement scale from the approximately conformal Lagrangian. Aside from such possible insights, the main purpose of addressing the strong interaction here - given that more sophisticated approaches already exist - is mostly to further verify the pertinence of the model in the more complex case of General Relativity for which non-perturbative methods are not as developed. The results have important implications on the nature of Dark Matter. In particular, non-perturbative effects naturally provide flat rotation curves for disk galaxies, without need for non-baryonic matter, and explain as well other observations involving Dark Matter such as cluster dynamics or the dark mass of elliptical galaxies. (orig.)

  17. High Energy Solar Spectroscopic Imager (HESSI) Team Investigations

    Science.gov (United States)

    Emslie, A. Gordon

    1998-01-01

    This report covers activities on the above grant for the period through the end of September 1997. The work originally proposed to be performed under a three-year award was converted at that time to a two-year award for the remainder of the period, and is now funded under award NAGS-4027 through Goddard Space Flight Center. The P.I. is a co-investigator on the High Energy Solar Spectroscopic Imager (HESSI) team, selected as a Small-Class Explorer (SNMX) mission in 1997. He has also been a participant in the Space Physics Roadmap Planning Group. Our research has been strongly influenced by the NASA mission opportunities related to these activities. The report is subdivided into four sections, each dealing with a different aspect of our research within this guiding theme. Personnel involved in this research at UAH include the P.I. and graduate students Michele Montgomery and Amy Winebarger. Much of the work has been carried out in collaboration with investigators at other institutions, as detailed below. Attachment: Laser wakefield acceleration and astrophysical applications.

  18. High magnetic field generation for laser-plasma experiments

    International Nuclear Information System (INIS)

    Pollock, B. B.; Froula, D. H.; Davis, P. F.; Ross, J. S.; Fulkerson, S.; Bower, J.; Satariano, J.; Price, D.; Krushelnick, K.; Glenzer, S. H.

    2006-01-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system supplying 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented

  19. An investigation of magnetic field effects on plume density and temperature profiles of an applied-field MPD thruster

    Science.gov (United States)

    Bullock, S. Ray; Myers, R. M.

    1994-01-01

    Applied-field magnetoplasmadynamic (MPD) thruster performance is below levels required for primary propulsion missions. While MPD thruster performance has been found to increase with the magnitude of the applied-field strength, there is currently little understanding of the impact of applied-field shape on thruster performance. The results of a study in which a single applied-field thruster was operated using three solenoidal magnets with diameters of 12.7, 15.2, and 30.4-cm are presented. Thruster voltage and anode power deposition were measured for each applied field shape over a range of field strengths. Plume electron number density and temperature distributions were measured using a Langmuir probe in an effort to determine the effect of field shape on plume confinement by the diverging magnetic-field for each of the three magnetic field shapes. Results show that the dependence of the measured thruster characteristics on field shape were non-monotonic and that the field shape had a significant effect on the plume density and temperature profiles.

  20. Field Evidence for a Low Permeability, High Storage Fault Core at the Santa Susana Field Laboratory

    Science.gov (United States)

    Allègre, V.; Brodsky, E. E.; Parker, B. L.; Cherry, J. A.

    2015-12-01

    In situ measurements of hydrogeologic properties within fault zones are few, in part because of the challenges of measuring the scale-dependent quantities in fractured rock reservoirs. This work aims to fill the gap by utilizing a combination of tidal, barometric and seismic response analyses on pressure head time-series from the Santa Susana Field Laboratory in Southern California. The techniques sample different effective volumes and so allow us to investigate the scale-dependent structure near fault zones. Permeability and specific storage were inverted from tidal response at 14 locations, and specific storage was also computed from barometric efficiencies at 10 locations. In addition, we computed hydro-seismic transfer functions after nine local earthquakes and teleseismic events. We found that permeability computed from tidal response are quite homogeneous within about one and a half orders of magnitude over the site regardless of the presence of moderate to large faults. This result is consistent with the earlier aquifer tests using standard methods. The tidal responses also showed higher variability of specific storage inside the fault zones suggesting that fault damage zone generates a storage architecture. The storage from the tidal responses can be consistently interpreted for the tidal, barometric and seismic responses. However, the observations require that the permeability inside the fault zones at the spatial scale of the seismic response (~meters) is much lower than at the spatial scale of the tidal response (~10's of meters). The result suggests possible sensitivity to the low permeability fault core, which has been historically difficult to measure at the field scale.

  1. Numerical and experimental investigation of the unsteady flow field over a simplified hydrofoil plate

    OpenAIRE

    Pislevikj, Jasmina

    2017-01-01

    In this thesis, the behavior of a simplified hydrofoil in an unsteady water flow field is tested. Due to frequent load variations in high head Francis turbines, the runner vanes happen to break. Rotor stator interaction causes vibrations on the runner vanes. To simulate those vibrations in laboratory conditions, the hydrofoil, mounted in a cascade test rig, is excited with piezo electric patches. The experiment in this thesis shows the behavior of the hydrofoil in different water flow velocit...

  2. Investigations of the magnetic fields from ships due to corrosion and its countermeasures

    Science.gov (United States)

    Allan, Peter J.

    Corrosion is one of the main concerns for the shipping industry. The enormous cost associated with the corrosion of ships means that operators are more than ever seeking methods to provide optimal protection. Another problem which results from the corrosion of ships is that the electric currents produced give rise to a corrosion related magnetic field which adds to the ships overall electromagnetic field which can trigger underwater mines. Hence for the Admiralty to protect their fleet, they need to understand, predict and reduce these electromagnetic signatures. This will also be a concern for operators of merchant ships if, as recently suggested, terrorists begin to target them. There are a number of factors contributing to the electromagnetic signature of a ship. The work presented in this study is concerned with the magnetic field arising due to corrosion and the countermeasures employed against it (namely Impressed Current Cathodic Protection (ICCP) systems]. This field is called the Corrosion Related Magnetic (CRM) field. Since this field is directly related to the rate of corrosion of a ship, it may also be used as an indicator as to the efficiency of the corrosion protection measures, This work presents a range of techniques which may be used to model the CRM field. Simple dipole models are used to investigate the general behaviour of a corroding ship in sea water. These investigations result in an expression for an approximation of the CRM field from a dipole-wire configuration which can be used to estimate the CRM field from a corroding ship with an active ICCP system. A second, more detailed, method was then developed using the Boundary Element Method (BEM) to model a ship corroding in a tank of sea water. The BEM uses a large set of simultaneous equations, the coefficients of which are calculated by numerical integration using a new method based around the moments of triangular surface elements which discretise the boundary of the domain. By using a

  3. Investigation of the High Mass Drell Yan Spectrum with ATLAS

    CERN Document Server

    Müller, Thomas

    The Large Hadron Collider started data taking at the end of 009 and an integrated luminosity of 1 fb^-1 is hoped for by the end of 2011. A precise measurement of the high mass Drell Yan spectrum offers a good opportunity for a model independent search for new physics. The muon channel is well suited for this, due to the clean signature and the good muon identification in the Muon Spectrometer. Previous studies at high dimuon masses neglected all background contributions. This study investigated the impact of background on the Drell Yan spectrum and it was found that top antitop decays are the most important contribution. Various selection cuts to suppress those background contributions were studied. A method to take systematic uncertainties into account, whilst optimising these selection cuts, has been developed. It was shown that two additional selection cuts based on b-tagging and Missing Transverse Energy (MET) will reduce the overall uncertainty for a bin from 200 GeV to 300 GeV from 19.1% to 17.2% for an...

  4. Preliminary investigations on high energy electron beam tomography

    Energy Technology Data Exchange (ETDEWEB)

    Baertling, Yves; Hoppe, Dietrich; Hampel, Uwe

    2010-12-15

    In computed tomography (CT) cross-sectional images of the attenuation distribution within a slice are created by scanning radiographic projections of an object with a rotating X-ray source detector compound and subsequent reconstruction of the images from these projection data on a computer. CT can be made very fast by employing a scanned electron beam instead of a mechanically moving X-ray source. Now this principle was extended towards high-energy electron beam tomography with an electrostatic accelerator. Therefore a dedicated experimental campaign was planned and carried out at the Budker Institute of Nuclear Physics (BINP), Novosibirsk. There we investigated the capabilities of BINP's accelerators as an electron beam generating and scanning unit of a potential high-energy electron beam tomography device. The setup based on a 1 MeV ELV-6 (BINP) electron accelerator and a single detector. Besides tomographic measurements with different phantoms, further experiments were carried out concerning the focal spot size and repeat accuracy of the electron beam as well as the detector's response time and signal to noise ratio. (orig.)

  5. Investigation of wind behaviour around high-rise buildings

    Science.gov (United States)

    Mat Isa, Norasikin; Fitriah Nasir, Nurul; Sadikin, Azmahani; Ariff Hairul Bahara, Jamil

    2017-09-01

    A study on the investigation of wind behaviour around the high-rise buildings is done through an experiment using a wind tunnel and computational fluid dynamics. High-rise buildings refer to buildings or structures that have more than 12 floors. Wind is invisible to the naked eye; thus, it is hard to see and analyse its flow around and over buildings without the use of proper methods, such as the use of wind tunnel and computational fluid dynamics software.The study was conducted on buildings located in Presint 4, Putrajaya, Malaysia which is the Ministry of Rural and Regional Development, Ministry of Information Communications and Culture, Ministry of Urban Wellbeing, Housing and Local Government and the Ministry of Women, Family, and Community by making scaled models of the buildings. The parameters in which this study is conducted on are, four different wind velocities used based on the seasonal monsoons, and wind direction. ANSYS Fluent workbench software is used to compute the simulations in order to achieve the objectives of this study. The data from the computational fluid dynamics are validated with the experiment done through the wind tunnel. From the results obtained through the use of the computation fluid dynamics, this study can identify the characteristics of wind around buildings, including boundary layer of the buildings, separation flow, wake region and etc. Then analyses is conducted on the occurance resulting from the wind that passes the buildings based on the velocity difference between before and after the wind passes the buildings.

  6. High field Moessbauer study of dilute Ir-(Fe) alloys

    International Nuclear Information System (INIS)

    Takabatake, Toshiro; Mazaki, Hiromasa; Shinjo, Teruya.

    1981-01-01

    The magnetic behavior of very dilute Fe impurities in Ir has been studied by means of Moessbauer measurement in external fields up to 80 kOe at 4.2 K. The saturation hyperfine field increases in proportion to the external field up to the maximum magnetic field available. This means that for a localized spin fluctuation system IrFe, the effective magnetic moment associated with Fe impurities is induced in proportion to the external field. No anomalous spectrum was observed with a very dilute sample (--10 ppm 57 Co), indicating that the interaction between impurities is responsible for the anomalous spectrum previously observed with a less homogeneous sample. (author)

  7. Crystal-field investigations of rare-earth-doped wide band gap semiconductors

    CERN Multimedia

    Muller, S; Wahl, U

    Crystal field investigations play a central role in the studies of rare earth doped semiconductors. Optical stark level spectroscopy and lattice location studies of radioactive rare earth isotopes implanted at ISOLDE have provided important insight into these systems during the last years. It has been shown that despite a major site preference of the probe atoms in the lattice, several defect configurations do exist. These sites are visible in the optical spectra but their origin and nature aren't deducible from these spectra alone. Hyperfine measurements on the other hand should reveal these defect configurations and yield the parameters necessary for a description of the optical properties at the atomic scale. In order to study the crystal field with this alternative approach, we propose a new concept for perturbed $\\gamma\\gamma$-angular correlation (PAC) experiments at ISOLDE based on digital signal processing in contrast to earlier analog setups. The general functionality of the spectrometer is explained ...

  8. Laboratory and field investigation of chemical disinfection of combined sewer overflow in Copenhagen area

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

    We investigated the possibility to apply performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA to Escherichia coli (E. coli) and enterococcus were studied in batch scale...... and pre-field experiment. In batch scale experiment 2.5 mg·L -1 PAA removed around 4 log unit of E. coli and enterococcus from CSO with long contact time. Removal of E. coli and enterococcus from CSO were always around or above 3 log unit using 2-4 mg·L -1 PFA with short contact time in batch scale...... and pre-field experiment. There were no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA, slight toxicological effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event. Disinfection...

  9. Photoelastic and analytical investigation of stress in toroidal magnetic field coils

    International Nuclear Information System (INIS)

    Pih, H.; Gray, W.H.

    1975-01-01

    A series of two-dimensional photoelastic stress analyses on circular and oval toroidal magnetic field coils for fusion reactors were made. The circumferential variation of the coil's magnetic force was simulated by applying different pressures to sixteen segmented regions of the inner surface of the models. Isochromatics and isoclinics were measured at selected points on the loaded model in a transmission polariscope using a microphotometer. Separate principal stresses were obtained using the combination of photoelastic information and isopachic data measured from the solution of Laplace's equation by the electrical analog method. Analysis of the same coil geometries, loadings, and boundary conditions were made using the finite element method. General agreement between theory and experiment was realized. From this investigation several variations of coil geometry and methods of support were evaluated. Based upon this experiment, suggestions for optimum structural design of toroidal field coils are presented

  10. Nanoscale investigation of enhanced electron field emission for silver ion implanted/post-annealed ultrananocrystalline diamond films.

    Science.gov (United States)

    Panda, Kalpataru; Hyeok, Jeong Jin; Park, Jeong Young; Sankaran, Kamatchi Jothiramalingam; Balakrishnan, Sundaravel; Lin, I-Nan

    2017-11-24

    Silver (Ag) ions are implanted in ultrananocrystalline diamond (UNCD) films to enhance the electron field emission (EFE) properties, resulting in low turn-on field of 8.5 V/μm with high EFE current density of 6.2 mA/cm 2 (at an applied field of 20.5 V/μm). Detailed nanoscale investigation by atomic force microscopy based peak force-controlled tunneling atomic force microscopy (PF-TUNA) and ultra-high vacuum scanning tunneling microscopy (STM) based current imaging tunneling spectroscopy (CITS) reveal that the UNCD grain boundaries are the preferred electron emission sites. The two scanning probe microscopic results supplement each other well. However, the PF-TUNA measurement is found to be better for explaining the local electron emission behavior than the STM-based CITS technique. The formation of Ag nanoparticles induced abundant sp 2 nanographitic phases along the grain boundaries facilitate the easy transport of electrons and is believed to be a prime factor in enhancing the conductivity/EFE properties of UNCD films. The nanoscale understanding on the origin of electron emission sites in Ag-ion implanted/annealed UNCD films using the scanning probe microscopic techniques will certainly help in developing high-brightness electron sources for flat-panel displays applications.

  11. Investigation of polymer composite for high dose dosimetry

    International Nuclear Information System (INIS)

    Pereira, E.L.M.; Batista, A.S.M.; Ribeiro, F.A.S.; Santos, A.P.; Faria, L.O.; Oliveira, A.H.

    2017-01-01

    Introduction: This paper presents the efficacy evaluation of PVDF and nanocomposites of the PVDF films for high gamma dosimetry. Our scope in this first part of our studies is the selection of the most promising film for future dosimetry trials, where the proportionality of response of the selected material will be investigated over a large range of doses and dose rates. Methods: Was prepared nanocomposites made by mixing Poly(vinylidene fluoride) (PVDF), zirconium oxide (ZrO 2 ) and multi-walled carbon nanotubes (MWCNTs) aiming to find dosimetric properties for applications in high dose dosimetry. The samples were irradiated with a Co-60 source at constant dose rate (16.7 kGy/h), with doses ranging from 100 to 2750 kGy. The UV-Vis and FTIR spectrophotometry have been used to monitor the appearing of C=C conjugated bonds and radio-oxidation of carbon (C=O). Results: FTIR spectrometry has that the absorbance intensities at 1715 cm -1 and 1730 cm -1 can be used for high dosimetry purposes for gamma doses ranging from 400 to 2750 kGy. In this range, it is possible to observe a linear relationship between Abs & Dose. Fading of signal was evaluated for one month and reproducibility in 2000 kGy dose. Conclusion: FTIR spectroscopic data revealed two optical absorption bands at 1715 cm -1 and 1730 cm -1 whose intensities are unambiguously related to gamma delivered dose ranging from 400 kGy to 2750 kGy. (author)

  12. Study of the magnetic superconductor, Y9Co7, at high pressure and high magnetic field

    International Nuclear Information System (INIS)

    Huang, C.Y.; Olsen, C.E.; Fuller, W.W.; Huang, J.H.; Wolf, S.A.

    1983-01-01

    The electrical resistance and magnetic susceptibility of the magnetic superconductor, Y 9 Co 7 has been measured at pressures up to 20 kbar and in magnetic fields up to 6T. It has been found that pressure suppresses the magnetism resulting in a higher superconducting transition temperature and conclude that Y 9 Co 7 is an itinerant ferromagnet, not a spin-glass. Pressure also sharpens the superconducting transition and increases the critical magnetic field, signifying that the long range ferromagnetic and superconducting order parameters co-exist but vary spatially. For pressures greater than 6 kbar, the magnetoresistance is always positive, further indicating the suppression of magnetism by high pressure. (author)

  13. Fuzzy cluster analysis of high-field functional MRI data.

    Science.gov (United States)

    Windischberger, Christian; Barth, Markus; Lamm, Claus; Schroeder, Lee; Bauer, Herbert; Gur, Ruben C; Moser, Ewald

    2003-11-01

    Functional magnetic resonance imaging (fMRI) based on blood-oxygen level dependent (BOLD) contrast today is an established brain research method and quickly gains acceptance for complementary clinical diagnosis. However, neither the basic mechanisms like coupling between neuronal activation and haemodynamic response are known exactly, nor can the various artifacts be predicted or controlled. Thus, modeling functional signal changes is non-trivial and exploratory data analysis (EDA) may be rather useful. In particular, identification and separation of artifacts as well as quantification of expected, i.e. stimulus correlated, and novel information on brain activity is important for both, new insights in neuroscience and future developments in functional MRI of the human brain. After an introduction on fuzzy clustering and very high-field fMRI we present several examples where fuzzy cluster analysis (FCA) of fMRI time series helps to identify and locally separate various artifacts. We also present and discuss applications and limitations of fuzzy cluster analysis in very high-field functional MRI: differentiate temporal patterns in MRI using (a) a test object with static and dynamic parts, (b) artifacts due to gross head motion artifacts. Using a synthetic fMRI data set we quantitatively examine the influences of relevant FCA parameters on clustering results in terms of receiver-operator characteristics (ROC) and compare them with a commonly used model-based correlation analysis (CA) approach. The application of FCA in analyzing in vivo fMRI data is shown for (a) a motor paradigm, (b) data from multi-echo imaging, and (c) a fMRI study using mental rotation of three-dimensional cubes. We found that differentiation of true "neural" from false "vascular" activation is possible based on echo time dependence and specific activation levels, as well as based on their signal time-course. Exploratory data analysis methods in general and fuzzy cluster analysis in particular may

  14. High-spin chloro mononuclear MnIII complexes: a multifrequency high-field EPR study.

    Science.gov (United States)

    Mantel, Claire; Chen, Hongyu; Crabtree, Robert H; Brudvig, Gary W; Pécaut, Jacques; Collomb, Marie-Noëlle; Duboc, Carole

    2005-03-01

    The isolation, structural characterization, and electronic properties of two six-coordinated chloromanganese (III) complexes, [Mn(terpy)(Cl)3] (1) and [Mn(Phterpy)(Cl)3] (2), are reported (terpy = 2,2':6'2"-terpyridine, Phterpy = 4'-phenyl-2,2':6',2"-terpyridine). These complexes complement a series of mononuclear azide and fluoride Mn(lll) complexes synthesized with neutral N-tridentate ligands, [Mn(L)(X)3] (X = F- or N3 and L = terpy or bpea [N,N-bis(2-pyridylmethyl)-ethylamine)], previously described. Similar to these previous complexes, 1 and 2 exhibit a Jahn-Teller distortion of the octahedron, characteristic of a high-spin Mn(III) complex (S = 2). The analysis of the crystallographic data shows that, in both cases, the manganese ion lies in the center of a distorted octahedron characterized by an elongation along the tetragonal axis. Their electronic properties were investigated by multifrequency EPR (190-475 GHz) performed in the solid state at different temperatures (5-15 K). This study confirms our previous results and further shows that: i) the sign of D is correlated with the nature of the tetragonal distortion; ii) the magnitude of D is not sensitive to the nature of the anions in our series of rhombic complexes, contrary to the porphyrinic systems; iii) the [E/D] values (0.124 for 1 and 0.085 for 2) are smaller compared to those found for the [Mn(L)(X)3] complexes (in the range of 0.146 to 0.234); and iv) the E term increases when the ligand-field strength of the equatorial ligands decreases.

  15. Shielding for radiation scattered dose distribution to the outside fields in patients treated with high energy radiotherapy beams

    International Nuclear Information System (INIS)

    Sung Sil Chu

    2001-01-01

    Scattered dose of therapeutic high energy radiation beams contributed significant unwanted dose to the patient. Measurement of radiation scattered dose outside fields and critical organs, like fetus position and testicle region, from chest or pelvic irradiation by large field of high energy radiation beam, was performed using an ionization chamber and film dosimetry. The scattered doses outside field were measured 5-10% of maximum doses in fields and exponentially decrease from field margins. The scattered photon dose received the uterus from thorax field irradiation and was measured about 1mGy/Gy of photon treatment dose. Shielding construction to reduce this scattered dose was investigated using lead sheet and blocks About 6 cm lead block shield reduced the scatter photon dose under 10mGy for 60Gy on abdomen field and almost reduced electron contamination. (author)

  16. Investigation of Interaction between Deferoxamine and Low Frequency Electromagnetic Field on Angiogenesis in Chick Embryo

    Directory of Open Access Journals (Sweden)

    Atena Dashtizadeh

    2015-02-01

    Full Text Available Background: Deferoxamine (DFO is an iron chelator. In the present research, the synergic effects of deferoxamine and electromagnetic field (with 50 H frequency and 100 Gauss intensity on angiogenesis of chick chorioallantoic membrane were investigated. Materials and Methods: In this experimental study 80 fertilized egg used and randomly divided 8 group: control group, laboratory control groups of 1 and 2, experimental group 1 (treatment with electromagnetic field, 2 and 3 (treatment with deferoxamine 10, 100 µmol, respectively, 4 and 5 (treatment both deferoxamine 10 and 100 µmol respectively and electromagnetic field. On 8th day of incubation, 2 and 4 groups were incubated with 10 µL deferoxamine and for 3 and 5 groups were incubated with 10 µL deferoxamine 100 µmol. On 10th day, 1, 4 and 5 groups were put in electromagnetic field. On 12th day, the number and length of vessels in all samples was measured by Image J software. Data were analyzed by SPSS-19, ANOVA and t-test. Results: The mean number and length of vessels in the control and experimental cases did not show any significant differences. Comparison between mean number of vessels in the control and group 2, 3, 4, 5 showed a significant decrease (p<0.05 and groups 2 and 4 was showed a significant decrease in the mean length of vessels compared with the controls (p<0.05. Conclusion: Using deferoxamine with low frequency electromagnetic field (50 Hz and 100 G cause inhibition of angiogenesis in chick embryo chorioallantoic membrane.

  17. High-repetition-rate PIV investigations on a generic rocket model in sub- and supersonic flows

    Science.gov (United States)

    Bitter, Martin; Scharnowski, Sven; Hain, Rainer; Kähler, Christian J.

    2011-04-01

    High-repetition-rate PIV measurements were performed in the trisonic wind tunnel facility at the Bundeswehr University Munich in order to investigate the boundary layer parameters on a generic rocket model and the recirculation area in the wake of the model at Mach numbers up to Mach = 2.6. The data are required for the validation of unsteady flow simulations. Because of the limited run time of the blow-down wind tunnel, a high-repetition-rate PIV system was applied to obtain the flow statistics with high accuracy. The results demonstrate this method's potential to resolve small-scale flow phenomena over a wide field of view in a large Mach number range but also show its limitations for the investigations of wall-bounded flows.

  18. An analytical method for the investigation of instability of a collisionless plasma in strong magnetic fields

    International Nuclear Information System (INIS)

    Zakharov, V.U.

    1993-01-01

    An analytical method for the investigation of special types of dispersion relations is presented. In particular, analysis of the propagation of small-amplitude hydromagnetic waves in a collisionless plasma in a strong magnetic field leads to such dispersion relations. The fifth-degree dispersion relation corresponding to a particular case is considered. The necessary stability condition for a steady state and conditions for the degeneration of small-amplitude waves are derived. A comparison with other methods for the analysis of similar dispersion relations is also presented. (author)

  19. Experimental investigation of a collisionless shock wave in a longitudinal magnetic field

    International Nuclear Information System (INIS)

    El-Khalafawy, T.A.; El-Nicklawy, M.; Beshara, A.B.; Abo-Ellil, M.S.

    1978-01-01

    The results of the experimental investigations of the parameters and the structure of a shock wave propagating along a static magnetic field are discussed. It is also shown that the wave observed experimentally represents a ''switch-on'' shock and its front structure is determined by the mechanism of the energy collisionless dissipation. In case of small Alfvene-Mach numbers I 3 smaller than the conductivity caused by Coulombs' collisions. The paper describes briefly the installation and also the probe methods of measuring the main plasma parameters, (the electron temperature Tsub(e) and the density nsub(e))

  20. Low field-low cost: Can low-field magnetic resonance systems replace high-field magnetic resonance systems in the diagnostic assessment of multiple sclerosis patients?

    International Nuclear Information System (INIS)

    Ertl-Wagner, B.B.; Reith, W.; Sartor, K.

    2001-01-01

    As low-field MR imaging is becoming a widely used imaging technique, we aimed at a prospective assessment of differences in imaging quality between low- and high-field MR imaging in multiple sclerosis patients possibly interfering with diagnostic or therapeutic decision making. Twenty patients with clinically proven multiple sclerosis were examined with optimized imaging protocols in a 1.5- and a 0.23-T MR scanner within 48 h. Images were assessed independently by two neuroradiologists. No statistically significant interrater discrepancies were observed. A significantly lower number of white matter lesions could be identified in low-field MR imaging both on T1- and on T2-weighted images (T2: high field 700, low field 481; T1: high field 253, low field 177). A total of 114 enhancing lesions were discerned in the high-field MR imaging as opposed to 45 enhancing lesions in low-field MR imaging. Blood-brain barrier disruption was identified in 11 of 20 patients in the high-field MR imaging, but only in 4 of 20 patients in low-field MR imaging. Since a significantly lower lesion load is identified in low-field MR imaging than in high-field MR imaging, and blood-brain barrier disruption is frequently missed, caution must be exercised in interpreting a normal low-field MR imaging scan in a patient with clinical signs of multiple sclerosis and in interpreting a scan without enhancing lesions in a patient with known multiple sclerosis and clinical signs of exacerbation. (orig.)

  1. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    International Nuclear Information System (INIS)

    Han, K.; Embury, J.D.

    1998-01-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications

  2. Survey of Processing Methods for High Strength High Conductivity Wires for High Field Magnet Applications

    Energy Technology Data Exchange (ETDEWEB)

    Han, K.; Embury, J.D.

    1998-10-01

    This paper will deal with the basic concepts of attaining combination of high strength and high conductivity in pure materials, in-situ composites and macrocomposites. It will survey current attainments, and outline where some future developments may lie in developing wire products that are close to the theoretical strength of future magnet applications.

  3. The New High Magnetic Field Laboratory at Dresden: a Pulsed-Field Laboratory at an IR Free-Electron-Laser

    International Nuclear Information System (INIS)

    Pobell, F.; Bianchi, A. D.; Herrmannsdoerfer, T.; Krug, H.; Zherlitsyn, S.; Zvyagin, S.; Wosnitza, J.

    2006-01-01

    We report on the construction of a new high magnetic field user laboratory which will offer pulsed-field coils in the range (60 T, 500 ms, 40 mm) to (100 T, 10 ms, 20 mm) for maximum field, pulse time, and bore diameter of the coils. These coils will be energized by a modular 50 MJ/24 kV capacitor bank. Besides many other experimental techniques, as unique possibilities NMR in pulsed fields as well as infrared spectroscopy at 5 to 150 μm will be available by connecting the pulsed field laboratory to a nearby free-electron-laser facility

  4. A high-gain high-power L-band antenna for field test applications

    Science.gov (United States)

    Abe, David K.; Tran, George T.; Knop, C. M.

    1995-09-01

    A high-gain, prime-focus parabolic dish antenna system was designed and constructed for experimental use in the field. The antenna was designed to radiate in L-band at peak power levels exceeding 1 X 106 watts. A 3.6 m diameter, commercial off-the-shelf parabolic dish antenna was modified with a custom-designed waveguide horn feed. The system was mounted on an antenna pedestal to allow for fine (approximately 0.001 degrees) elevation and azimuth control; the antenna and pedestal were mounted on a 4.3 m long trailer for mobility in the field. The antenna has a measured gain of 32 dBi and a 3-dB beamwidth of approximately 4.5 degrees. The system was successfully operated in the field in L-band at peak power levels exceeding 5 MW. The design, calibration, and testing of the antenna system will be presented.

  5. Transport studies in high-performance field reversed configuration plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S., E-mail: sgupta@trialphaenergy.com; Barnes, D. C.; Dettrick, S. A.; Trask, E.; Tuszewski, M.; Deng, B. H.; Gota, H.; Gupta, D.; Hubbard, K.; Korepanov, S.; Thompson, M. C.; Zhai, K.; Tajima, T. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

    2016-05-15

    A significant improvement of field reversed configuration (FRC) lifetime and plasma confinement times in the C-2 plasma, called High Performance FRC regime, has been observed with neutral beam injection (NBI), improved edge stability, and better wall conditioning [Binderbauer et al., Phys. Plasmas 22, 056110 (2015)]. A Quasi-1D (Q1D) fluid transport code has been developed and employed to carry out transport analysis of such C-2 plasma conditions. The Q1D code is coupled to a Monte-Carlo code to incorporate the effect of fast ions, due to NBI, on the background FRC plasma. Numerically, the Q1D transport behavior with enhanced transport coefficients (but with otherwise classical parametric dependencies) such as 5 times classical resistive diffusion, classical thermal ion conductivity, 20 times classical electron thermal conductivity, and classical fast ion behavior fit with the experimentally measured time evolution of the excluded flux radius, line-integrated density, and electron/ion temperature. The numerical study shows near sustainment of poloidal flux for nearly 1 ms in the presence of NBI.

  6. High resolution geomagnetic field observations at Terra Nova bay, Antarctica

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1996-06-01

    Full Text Available he preliminary results obtained from the analysis in the micropulsation frequency range of high time resolution magnetic field data recorded at the Antarctic Italian geomagnetic observatory at Terra Nova Bay for 11 consecutive days in February 1994 are reported. The spectral index over the whole Pcl-Pc5 frequency range is of the order of 3.5 and its value significantly increases beyond about 50 mHz. Spectral peaks in the Pc3 frequency range are common, especially during the daytime hours, and are probably due to the direct penetration of upstream waves in the cusp region. From the local time distribution of the micro pulsation power, a signifi - cant activity enhancement around the local magnetic noon emerges, in agreement with previous observations. The analysis of the signal polarisation characteristics in the horizontal plane shows a predominant CW polarisation in the Pcl-Pc3 frequency ranges with the major axis of the polarisation ellipse in the first quadrant.

  7. ADX: a high field, high power density, advanced divertor and RF tokamak

    Science.gov (United States)

    LaBombard, B.; Marmar, E.; Irby, J.; Terry, J. L.; Vieira, R.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; Baek, S.; Beck, W.; Bonoli, P.; Brunner, D.; Doody, J.; Ellis, R.; Ernst, D.; Fiore, C.; Freidberg, J. P.; Golfinopoulos, T.; Granetz, R.; Greenwald, M.; Hartwig, Z. S.; Hubbard, A.; Hughes, J. W.; Hutchinson, I. H.; Kessel, C.; Kotschenreuther, M.; Leccacorvi, R.; Lin, Y.; Lipschultz, B.; Mahajan, S.; Minervini, J.; Mumgaard, R.; Nygren, R.; Parker, R.; Poli, F.; Porkolab, M.; Reinke, M. L.; Rice, J.; Rognlien, T.; Rowan, W.; Shiraiwa, S.; Terry, D.; Theiler, C.; Titus, P.; Umansky, M.; Valanju, P.; Walk, J.; White, A.; Wilson, J. R.; Wright, G.; Zweben, S. J.

    2015-05-01

    The MIT Plasma Science and Fusion Center and collaborators are proposing a high-performance Advanced Divertor and RF tokamak eXperiment (ADX)—a tokamak specifically designed to address critical gaps in the world fusion research programme on the pathway to next-step devices: fusion nuclear science facility (FNSF), fusion pilot plant (FPP) and/or demonstration power plant (DEMO). This high-field (⩾6.5 T, 1.5 MA), high power density facility (P/S ˜ 1.5 MW m-2) will test innovative divertor ideas, including an ‘X-point target divertor’ concept, at the required performance parameters—reactor-level boundary plasma pressures, magnetic field strengths and parallel heat flux densities entering into the divertor region—while simultaneously producing high-performance core plasma conditions that are prototypical of a reactor: equilibrated and strongly coupled electrons and ions, regimes with low or no torque, and no fuelling from external heating and current drive systems. Equally important, the experimental platform will test innovative concepts for lower hybrid current drive and ion cyclotron range of frequency actuators with the unprecedented ability to deploy launch structures both on the low-magnetic-field side and the high-magnetic-field side—the latter being a location where energetic plasma-material interactions can be controlled and favourable RF wave physics leads to efficient current drive, current profile control, heating and flow drive. This triple combination—advanced divertors, advanced RF actuators, reactor-prototypical core plasma conditions—will enable ADX to explore enhanced core confinement physics, such as made possible by reversed central shear, using only the types of external drive systems that are considered viable for a fusion power plant. Such an integrated demonstration of high-performance core-divertor operation with steady-state sustainment would pave the way towards an attractive pilot plant, as envisioned in the ARC concept

  8. Perspectives for the high field approach in fusion research and advances within the Ignitor Program

    Science.gov (United States)

    Coppi, B.; Airoldi, A.; Albanese, R.; Ambrosino, G.; Belforte, G.; Boggio-Sella, E.; Cardinali, A.; Cenacchi, G.; Conti, F.; Costa, E.; D'Amico, A.; Detragiache, P.; De Tommasi, G.; DeVellis, A.; Faelli, G.; Ferraris, P.; Frattolillo, A.; Giammanco, F.; Grasso, G.; Lazzaretti, M.; Mantovani, S.; Merriman, L.; Migliori, S.; Napoli, R.; Perona, A.; Pierattini, S.; Pironti, A.; Ramogida, G.; Rubinacci, G.; Sassi, M.; Sestero, A.; Spillantini, S.; Tavani, M.; Tumino, A.; Villone, F.; Zucchi, L.

    2015-05-01

    The Ignitor Program maintains the objective of approaching D-T ignition conditions by incorporating systematical advances made with relevant high field magnet technology and with experiments on high density well confined plasmas in the present machine design. An additional objective is that of charting the development of the high field line of experiments that goes from the Alcator machine to the ignitor device. The rationale for this class of experiments, aimed at producing poloidal fields with the highest possible values (compatible with proven safety factors of known plasma instabilities) is given. On the basis of the favourable properties of high density plasmas produced systematically by this line of machines, the envisioned future for the line, based on novel high field superconducting magnets, includes the possibility of investigating more advanced fusion burn conditions than those of the D-T plasmas for which Ignitor is designed. Considering that a detailed machine design has been carried out (Coppi et al 2013 Nucl. Fusion 53 104013), the advances made in different areas of the physics and technology that are relevant to the Ignitor project are reported. These are included within the following sections of the present paper: main components issues, assembly and welding procedures; robotics criteria; non-linear feedback control; simulations with three-dimensional structures and disruption studies; ICRH and dedicated diagnostics systems; anomalous transport processes including self-organization for fusion burning regimes and the zero-dimensional model; tridimensional structures of the thermonuclear instability and control provisions; superconducting components of the present machine; envisioned experiments with high field superconducting magnets.

  9. Investigations of solutions of Einstein's field equations close to {lambda}-Taub-NUT

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Florian [KTH Matematik, 10044 Stockholm (Sweden)], E-mail: fbeyer@math.kth.se

    2008-12-07

    We present investigations of a class of solutions of Einstein's field equations close to the family of {lambda}-Taub-NUT spacetimes. The studies are done using a numerical code introduced by the author elsewhere. One of the main technical complications is due to the paragraph -topology of the Cauchy surfaces. Complementing these numerical results with heuristic arguments, we are able to yield some first insights into the strong cosmic censorship issue and the conjectures by Belinskii, Khalatnikov and Lifschitz in this class of spacetimes. In particular, the current investigations suggest that strong cosmic censorship holds in this class. We further identify open issues in our current approach and point to future research projects.

  10. A six-bank multi-leaf system for high precision shaping of large fields

    International Nuclear Information System (INIS)

    Topolnjak, R; Heide, U A van der; Raaymakers, B W; Kotte, A N T J; Welleweerd, J; Lagendijk, J J W

    2004-01-01

    In this study, we present the design for an alternative MLC system that allows high precision shaping of large fields. The MLC system consists of three layers of two opposing leaf banks. The layers are rotated 60 deg. relative to each other. The leaves in each bank have a standard width of 1 cm projected at the isocentre. Because of the symmetry of the collimator set-up it is expected that collimator rotation will not be required, thus simplifying the construction considerably. A 3D ray tracing computer program was developed in order to simulate the fluence profile for a given collimator and used to optimize the design and investigate its performance. The simulations show that a six-bank collimator will afford field shaping of fields of about 40 cm diameter with a precision comparable to that of existing mini MLCs with a leaf width of 4 mm

  11. Spin dynamics in relativistic ionization with highly charged ions in super-strong laser fields

    International Nuclear Information System (INIS)

    Klaiber, Michael; Yakaboylu, Enderalp; Bauke, Heiko; Hatsagortsyan, Karen Z; Müller, Carsten; Paulus, Gerhard G

    2014-01-01

    Spin dynamics and induced spin effects in above-threshold ionization of hydrogenlike highly charged ions in super-strong laser fields are investigated. Spin-resolved ionization rates in the tunnelling regime are calculated by employing two versions of a relativistic Coulomb-corrected strong-field approximation (SFA). An intuitive simpleman model is developed which explains the derived scaling laws for spin flip and spin asymmetry effects. The intuitive model as well as our ab initio numerical simulations support the analytical results for the spin effects obtained in the dressed SFA where the impact of the laser field on the electron spin evolution in the bound state is taken into account. In contrast, the standard SFA is shown to fail in reproducing spin effects in ionization even at a qualitative level. The anticipated spin-effects are expected to be measurable with modern laser techniques combined with an ion storage facility. (paper)

  12. Numerical Investigation of Fuel Distribution Effect on Flow and Temperature Field in a Heavy Duty Gas Turbine Combustor

    Science.gov (United States)

    Deng, Xiaowen; Xing, Li; Yin, Hong; Tian, Feng; Zhang, Qun

    2018-03-01

    Multiple-swirlers structure is commonly adopted for combustion design strategy in heavy duty gas turbine. The multiple-swirlers structure might shorten the flame brush length and reduce emissions. In engineering application, small amount of gas fuel is distributed for non-premixed combustion as a pilot flame while most fuel is supplied to main burner for premixed combustion. The effect of fuel distribution on the flow and temperature field related to the combustor performance is a significant issue. This paper investigates the fuel distribution effect on the combustor performance by adjusting the pilot/main burner fuel percentage. Five pilot fuel distribution schemes are considered including 3 %, 5 %, 7 %, 10 % and 13 %. Altogether five pilot fuel distribution schemes are computed and deliberately examined. The flow field and temperature field are compared, especially on the multiple-swirlers flow field. Computational results show that there is the optimum value for the base load of combustion condition. The pilot fuel percentage curve is calculated to optimize the combustion operation. Under the combustor structure and fuel distribution scheme, the combustion achieves high efficiency with acceptable OTDF and low NOX emission. Besides, the CO emission is also presented.

  13. Numerical investigation of temperature field in magnetic hyperthermia considering mass transfer and diffusion in interstitial tissue

    Science.gov (United States)

    Tang, Yundong; Flesch, Rodolfo C. C.; Jin, Tao

    2018-01-01

    Magnetic nanoparticle (MNP) hyperthermia ablates malignant cells by heating the region of interest when MNPs are subjected to an external alternating magnetic field. The energy density to be dissipated into heat, and consequently the temperature profile during treatment, depends on the distribution of MNPs within the tumoral region. This paper uses numerical models to evaluate the temporal and spatial temperature distributions inside a tumor when intratumoral injection of MNPs is considered. To this end, the theories of mass transfer and diffusion in interstitial tissue are combined with Rosensweig’s theory and Pennes bio-heat transfer equation, and the finite element method is used for analyzing the temperature field under different scenarios. Simulation results demonstrate that the treatment temperature field strongly depends on factors, such as the injection method, particle size, injection concentration and injection dose. However, the maximal temperature reached during hyperthermia and the effective treatment area are difficult to control. In order to obtain better treatment effects, this paper investigates a solution that uses a kind of material with low Curie temperature and the results show that the effective treatment area of hyperthermia can be significantly improved using this type of MNP.

  14. Investigations of oil refinery effluent on fish in the field and laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.; Munkittrick, K. [New Brunswick Univ., Saint John, NB (Canada). Canadian Rivers Inst., Dept. of Biology; MacLatchy, D.L. [Wilfrid Laurier Univ., Waterloo, ON (Canada)

    2007-07-01

    Canada's largest oil refinery located near Saint John, New Brunswick, produces 270 000 barrels of oil/day and discharges effluent into the Little River at a rate of 24 274 m{sup 3}/day. The impact of refinery effluent on fish in the receiving environment has been under investigation since 2003. The efforts were first complicated by low dissolved oxygen attributed to ballast water released with the effluent. A more recent study was then initiated to assess any potential recovery after ballast water was removed from the effluent and to determine the effects of refinery effluent on fish. Potential recovery in the receiving environment was assessed through monthly fish surveys and by comparing recent data to previous studies. In order to clarify the effects that refinery effluents may have on fish, both laboratory and field studies were conducted with mummichog (Fundulus heteroclitus) and northern redbelly dace (Chrosomus eos). Both these brackish water species and freshwater species, respectively, were resident species. The field studies with caged mummichog revealed an increase in liver size relative to fish size and a decrease in condition of the fish downstream of the effluent discharge. Female testosterone levels and liver detoxification enzymes were also elevated. It was concluded that the reactions occurring in the field are more complicated than could be simulated in the laboratory.

  15. Investigation of the field dependent spin structure of exchange coupled magnetic heterostructures

    International Nuclear Information System (INIS)

    Gurieva, Tatiana

    2016-05-01

    This thesis describes the investigation of the field dependent magnetic spin structure of an antiferromagnetically (AF) coupled Fe/Cr heterostructure sandwiched between a hardmagnetic FePt buffer layer and a softmagnetic Fe top layer. The depth-resolved experimental studies of this system were performed via Magneto-optical Kerr effect (MOKE), Vibrating Sample Magnetometry (VSM) and various measuring methods based on nuclear resonant scattering (NRS) technique. Nucleation and evolution of the magnetic spiral structure in the AF coupled Fe/Cr multilayer structure in an azimuthally rotating external magnetic field were observed using NRS. During the experiment a number of time-dependent magnetic side effects (magnetic after-effect, domain-wall creep effect) caused by the non-ideal structure of a real sample were observed and later explained. Creation of the magnetic spiral structure in rotating external magnetic field was simulated using a one-dimensional micromagnetic model.The cross-sectional magnetic X-ray diffraction technique was conceived and is theoretically described in the present work. This method allows to determine the magnetization state of an individual layer in the magnetic heterostructure. It is also applicable in studies of the magnetic structure of tiny samples where conventional x-ray reflectometry fails.

  16. The Double Star magnetic field investigation: instrument design, performance and highlights of the first year's observations

    Directory of Open Access Journals (Sweden)

    C. Carr

    2005-11-01

    Full Text Available One of the primary objectives of the Double Star mission is the accurate measurement of the magnetic field vector along the orbits of the two spacecraft. The magnetic field is an essential parameter for the understanding of space plasma processes and is also required for the effective interpretation of data from the other instruments on the spacecraft. We present the design of the magnetic field instrument onboard both of the Double Star spacecraft and an overview of the performance as measured first on-ground and then in-orbit. We also report the results of in-flight calibration of the magnetometers, and the processing methods employed to produce the final data products which are provided to Double Star investigators, and the wider community in general. Particular attention is paid to the techniques developed for removing magnetic interference generated by the solar arrays on the first (equatorial orbiting spacecraft. Results from the first year of operations are reviewed in the context of combined observations by Double Star and Cluster, and examples given from the different regions visited by the spacecraft to date.

  17. Investigation of Oriented Magnetic Field Effects on Entropy Generation in an Inclined Channel Filled with Ferrofluids

    Directory of Open Access Journals (Sweden)

    Elgiz Baskaya

    2017-07-01

    Full Text Available Dispersion of super-paramagnetic nanoparticles in nonmagnetic carrier fluids, known as ferrofluids, offers the advantages of tunable thermo-physical properties and eliminate the need for moving parts to induce flow. This study investigates ferrofluid flow characteristics in an inclined channel under inclined magnetic field and constant pressure gradient. The ferrofluid considered in this work is comprised of Cu particles as the nanoparticles and water as the base fluid. The governing differential equations including viscous dissipation are non-dimensionalised and discretized with Generalized Differential Quadrature Method. The resulting algebraic set of equations are solved via Newton-Raphson Method. The work done here contributes to the literature by searching the effects of magnetic field angle and channel inclination separately on the entropy generation of the ferrofluid filled inclined channel system in order to achieve best design parameter values so called entropy generation minimization is implemented. Furthermore, the effect of magnetic field, inclination angle of the channel and volume fraction of nanoparticles on velocity and temperature profiles are examined and represented by figures to give a thorough understanding of the system behavior.

  18. Investigations on field-effect transistors based on two-dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Finge, T.; Riederer, F.; Grap, T.; Knoch, J. [Institute of Semiconductor Electronics, RWTH Aachen University (Germany); Mueller, M.R. [Institute of Semiconductor Electronics, RWTH Aachen University (Germany); Infineon Technologies, Villach (Austria); Kallis, K. [Intelligent Microsystems Chair, TU Dortmund University (Germany)

    2017-11-15

    In the present article, experimental and theoretical investigations regarding field-effect transistors based on two-dimensional (2D) materials are presented. First, the properties of contacts between a metal and 2D material are discussed. To this end, metal-to-graphene contacts as well to transition metal dichalcogenides (TMD) are studied. Whereas metal-graphene contacts can be tuned with an appropriate back-gate, metal-TMD contacts exhibit strong Fermi level pinning showing substantially limited maximum possible drive current. Next, tungsten diselenide (WSe{sub 2}) field-effect transistors are presented. Employing buried-triple-gate substrates allows tuning source, channel and drain by applying appropriate gate voltages so that the device can be reconfigured to work as n-type, p-type and as so-called band-to-band tunnel field-effect transistor on the same WSe{sub 2} flake. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Investigating the impact of visuohaptic simulations for the conceptual understanding of electric field for distributed charges

    Science.gov (United States)

    Shaikh, Uzma Abdul Sattar

    The present study assessed the benefits of a multisensory intervention on the conceptual understanding of electric field for distributed charges in engineering and technology undergraduate students. A novel visuohaptic intervention was proposed, which focused on exploring the forces around the different electric field configurations for distributed charges namely point, infinitely long line and uniformly charged ring. The before and after effects of the visuohaptic intervention are compared, wherein the intervention includes instructional scaffolding. Three single-group studies were conducted to investigate the effect among three different populations: (a) Undergraduate engineering students, (b) Undergraduate technology students and (c) Undergraduate engineering technology students from a different demographic setting. The findings from the three studies suggests that the haptic modality intervention provides beneficial effects by allowing students to improve their conceptual understanding of electric field for distributed charges, although students from groups (b) and (c) showed a statistically significant increase in the conceptual understanding. The findings also indicate a positive learning perception among all the three groups.

  20. Experimental investigation of detonation waves instabilities in liquid high explosives

    Science.gov (United States)

    Sosikov, V. A.; Torunov, S. I.; Utkin, A. V.; Mochalova, V. M.; Rapota, D. Yu

    2018-01-01

    Experimental investigation of unstable detonation front structure in mixtures of liquid high explosives (nitromethane and FEFO—bis-(2-fluor-2.2-dinitroethyl)-formal) with inert diluents (acetone, methanol, DETA—diethylene triamine) has been carried out. Inhomogeneities have been registered by electro-optical camera NANOGATE 4BP allowing to make 4 frames with the exposure time 10 ns. According to experimental results the detonation front in nitromethane–acetone mixture is unstable. It is evident that pulsations on detonation front do not form spatial periodic structure and their dimensions differ several times. But mean longitudinal size of pulsation is about 500 μm at 20 wt% of acetone concentration. This means that the typical size of cell equals to reaction zone width. The same structure of cellular front have been registered in 70/30 FEFO–methanol mixture. Second kind of instability, failure waves, was observed in neat nitromethane at the free surface. In this case the stability loss result in turbulent flow which is clearly detected in the shots obtained. Adding small amount of DETA (0.5 wt%) results in disappearance of the failure waves and flow stabilization. The effect is caused by the fact that DETA sharply accelerates initial rate of chemical reaction because it is sensitizer for nitromethane.