WorldWideScience

Sample records for relevant magnetic parameters

  1. Magnetic S-parameter

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2010-01-01

    We propose a direct test of the existence of gauge duals for nonsupersymmetric asymptotically free gauge theories developing an infrared fixed point by computing the S-parameter in the electric and dual magnetic description. In particular we show that at the lower bound of the conformal window...... the magnetic S-parameter, i.e. the one determined via the dual magnetic gauge theory, assumes a simple expression in terms of the elementary magnetic degrees of freedom. The results further support our recent conjecture of the existence of a universal lower bound on the S parameter and indicates...

  2. Biotropic parameters of magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Shishlo, M.A.

    The use of magnetic fields (MF) in biology and medicine to control biological systems has led to appearance of the term, biotropic parameters of MF. They include the physical characteristics of MF, which determine the primary biologically significant physicochemical mechanisms of field action causing formation of corresponding reactions on the level of the integral organism. These parameters include MF intensity, gradient, vector, pulse frequency and shape, and duration of exposure. Factors that elicit responses by the biological system include such parameter of MF interaction with the integral organism as localization of exposure and volume of tissues interacting with the field, as well as the initial state of the organism. In essence, the findings of experimental studies of biotropic parameters of MF make it possible to control physiological processes and will aid in optimizing methods of MF therapy.

  3. Summary of existing superconducting magnet experience and its relevance to the safety of fusion magnet

    International Nuclear Information System (INIS)

    Hsieh, S.Y.; Allinger, J.; Danby, G.; Keane, J.; Powell, J.; Prodell, A.

    1975-01-01

    A comprehensive summary of experience with over twenty superconducting magnet systems has been collected through visits to and discussions about existing facilities including, for example, the bubble chamber magnets at Brookhaven National Laboratory, Argonne National Laboratory and Fermi National Accelerator Laboratory, and the large superconducting spectrometer at Stanford Linear Accelerator Center. This summary includes data relating to parameters of these magnets, magnet protection methods, and operating experiences. The information received is organized and presented in the context of its relevance to the safe operation of future, very large superconducting magnet systems for fusion power plants

  4. High-frequency parameters of magnetic films showing magnetization dispersion

    International Nuclear Information System (INIS)

    Sidorenkov, V.V.; Zimin, A.B.; Kornev, Yu.V.

    1988-01-01

    Magnetization dispersion leads to skewed resonance curves shifted towards higher magnetizing fields, together with considerable reduction in the resonant absorption, while the FMR line width is considerably increased. These effects increase considerably with frequency, in contrast to films showing magnetic-anisotropy dispersion, where they decrease. It is concluded that there may be anomalies in the frequency dependence of the resonance parameters for polycrystalline magnetic films

  5. Safe structural food bolus in elderly: the relevant parameters

    OpenAIRE

    Vandenberghe-Descamps, Mathilde; Septier, Chantal; Prot, Aurélie; Tournier, Carole; Hennequin, Martine; Vigneau, Evelyne; Feron, Gilles; Labouré, Hélène

    2017-01-01

    Mastication is essential to prepare food into a bolus ready to be swallowed safely, with no choking risk. Based on food bolus properties, a masticatory normative indicator was developed by Woda et al. (2010) to identify impaired masticatory function within good oral health population. The aim of the present study was to identify relevant parameters of bolus' structure to differentiate safe to unsafe bolus among elderly contrasting by their dental status.93 elderly, 58% with at least 7 posteri...

  6. Design-relevant mechanical properties of 316-type stainless steels for superconducting magnets

    Energy Technology Data Exchange (ETDEWEB)

    Tobler, R.L.; Nishimura, A.; Yamamoto, J.

    1996-08-01

    Worldwide interest in austenitic alloys for structural applications in superconducting magnets has led to an expanded database for the 316-type stainless steels. We review the cryogenic mechanical properties of wrought, cast, and welded steels at liquid helium temperature (4 K), focussing on aspects of material behavior relevant to magnet design. Fracture mechanics parameters essential to structural reliability assessments are presented, including strength, toughness, and fatigue parameters that are critical for some component designs. (author). 105 refs.

  7. Design-relevant mechanical properties of 316-type stainless steels for superconducting magnets

    International Nuclear Information System (INIS)

    Tobler, R.L.; Nishimura, A.; Yamamoto, J.

    1996-08-01

    Worldwide interest in austenitic alloys for structural applications in superconducting magnets has led to an expanded database for the 316-type stainless steels. We review the cryogenic mechanical properties of wrought, cast, and welded steels at liquid helium temperature (4 K), focussing on aspects of material behavior relevant to magnet design. Fracture mechanics parameters essential to structural reliability assessments are presented, including strength, toughness, and fatigue parameters that are critical for some component designs. (author). 105 refs

  8. SOLAR ERUPTION AND LOCAL MAGNETIC PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeongwoo; Chae, Jongchul [Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of); Liu, Chang; Jing, Ju [Space Weather Research Laboratory, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2016-11-10

    It is now a common practice to use local magnetic parameters such as magnetic decay index for explaining solar eruptions from active regions, but there can be an alternative view that the global properties of the source region should be counted as a more important factor. We discuss this issue based on Solar Dynamics Observatory observations of the three successive eruptions within 1.5 hr from the NOAA active region 11444 and the magnetic parameters calculated using the nonlinear force-free field model. Two violent eruptions occurred in the regions with relatively high magnetic twist number (0.5–1.5) and high decay index (0.9–1.1) at the nominal height of the filament (12″) and otherwise a mild eruption occurred, which supports the local-parameter paradigm. Our main point is that the time sequence of the eruptions did not go with these parameters. It is argued that an additional factor, in the form of stabilizing force, should operate to determine the onset of the first eruption and temporal behaviors of subsequent eruptions. As supporting evidence, we report that the heating and fast plasma flow continuing for a timescale of an hour was the direct cause for the first eruption and that the unidirectional propagation of the disturbance determined the timing of subsequent eruptions. Both of these factors are associated with the overall magnetic structure rather than local magnetic properties of the active region.

  9. Electroconvulsive Therapy In Neuropsychiatry : Relevance Of Seizure Parameters

    Directory of Open Access Journals (Sweden)

    Gangadhar BN

    2000-01-01

    Full Text Available Electroconvulsive therapy (ECT is used to induce therapeutic seizures in various clinical conditions. It is specifically useful in depression, catatonia, patients with high suicidal risk, and those intolerant to drugs. Its beneficial effects surpass its side effects. Memory impairment is benign and transient. Its mechanism of action is unknown, though numerous neurotransmitters and neuroreceptors have been implicated. The standards of ECT practice are well established but still evolving in some particularly in unilateral ECT. Assessment of threshold by formula method may deliver higher stimulus dose compared with titration method. Cerebral seizure during ECT procedure is necessary. Motor (cuff method and EEG seizure monitoring are mandatory. Recent studies have shown some EEG parameters (amplitude, fractal dimension, symmetry, and post ictal suppression to be associated with therapeutic outcome. Besides seizure monitoring, measuring other physiological parameters such as heart rate (HR and blood pressure (BP may be useful indicators of therapeutic response. Use of ECT in neurological conditions as well as its application in psychiatric illnesses associated with neurological disorders has also been reviewed briefly.

  10. Estimation of parameters of interior permanent magnet synchronous motors

    International Nuclear Information System (INIS)

    Hwang, C.C.; Chang, S.M.; Pan, C.T.; Chang, T.Y.

    2002-01-01

    This paper presents a magnetic circuit model to the estimation of machine parameters of an interior permanent magnet synchronous machine. It extends the earlier work of Hwang and Cho that focused mainly on the magnetic aspects of motor design. The proposed model used to calculate EMF, d- and q-axis reactances. These calculations are compared to those from finite element analysis and measurement with good agreement

  11. Estimation of parameters of interior permanent magnet synchronous motors

    CERN Document Server

    Hwang, C C; Pan, C T; Chang, T Y

    2002-01-01

    This paper presents a magnetic circuit model to the estimation of machine parameters of an interior permanent magnet synchronous machine. It extends the earlier work of Hwang and Cho that focused mainly on the magnetic aspects of motor design. The proposed model used to calculate EMF, d- and q-axis reactances. These calculations are compared to those from finite element analysis and measurement with good agreement.

  12. Hybrid superconducting-magnetic memory device using competing order parameters.

    Science.gov (United States)

    Baek, Burm; Rippard, William H; Benz, Samuel P; Russek, Stephen E; Dresselhaus, Paul D

    2014-05-28

    In a hybrid superconducting-magnetic device, two order parameters compete, with one type of order suppressing the other. Recent interest in ultra-low-power, high-density cryogenic memories has spurred new efforts to simultaneously exploit superconducting and magnetic properties so as to create novel switching elements having these two competing orders. Here we describe a reconfigurable two-layer magnetic spin valve integrated within a Josephson junction. Our measurements separate the suppression in the superconducting coupling due to the exchange field in the magnetic layers, which causes depairing of the supercurrent, from the suppression due to the stray magnetic field. The exchange field suppression of the superconducting order parameter is a tunable and switchable behaviour that is also scalable to nanometer device dimensions. These devices demonstrate non-volatile, size-independent switching of Josephson coupling, in magnitude as well as phase, and they may enable practical nanoscale superconducting memory devices.

  13. Two-parameter asymptotics in magnetic Weyl calculus

    International Nuclear Information System (INIS)

    Lein, Max

    2010-01-01

    This paper is concerned with small parameter asymptotics of magnetic quantum systems. In addition to a semiclassical parameter ε, the case of small coupling λ to the magnetic vector potential naturally occurs in this context. Magnetic Weyl calculus is adapted to incorporate both parameters, at least one of which needs to be small. Of particular interest is the expansion of the Weyl product which can be used to expand the product of operators in a small parameter, a technique which is prominent to obtain perturbation expansions. Three asymptotic expansions for the magnetic Weyl product of two Hoermander class symbols are proven as (i) ε<< 1 and λ<< 1, (ii) ε<< 1 and λ= 1, as well as (iii) ε= 1 and λ<< 1. Expansions (i) and (iii) are impossible to obtain with ordinary Weyl calculus. Furthermore, I relate the results derived by ordinary Weyl calculus with those obtained with magnetic Weyl calculus by one- and two-parameter expansions. To show the power and versatility of magnetic Weyl calculus, I derive the semirelativistic Pauli equation as a scaling limit from the Dirac equation up to errors of fourth order in 1/c.

  14. Magnetic field effect on flow parameters of blood along with magnetic particles in a cylindrical tube

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shashi, E-mail: shashisharma1984@gmail.com; Singh, Uaday; Katiyar, V.K.

    2015-03-01

    In this paper, the effect of external uniform magnetic field on flow parameters of both blood and magnetic particles is reported through a mathematical model using magnetohydrodynamics (MHD) approach. The fluid is acted upon by a varying pressure gradient and an external uniform magnetic field is applied perpendicular to the cylindrical tube. The governing nonlinear partial differential equations were solved numerically and found that flow parameters are affected by the influence of magnetic field. Further, artificial blood (75% water+25% Glycerol) along with iron oxide magnetic particles were prepared and transported into a glass tube with help of a peristaltic pump. The velocity of artificial blood along with magnetic particles was experimentally measured at different magnetic fields ranging from 100 to 600 mT. The model results show that the velocity of blood and magnetic particles is appreciably reduced under the influence of magnetic field, which is supported by our experimental results. - Highlights: • Effect of magnetic field on flow parameters of blood and magnetic particles is studied. • The velocity of blood and magnetic particles is appreciably reduced under a magnetic field. • Experimental results of the velocity of magnetic particles within blood support the mathematical model results.

  15. Static Magnetic Field Therapy: A Critical Review of Treatment Parameters

    Directory of Open Access Journals (Sweden)

    Agatha P. Colbert

    2009-01-01

    Full Text Available Static magnetic field (SMF therapy, applied via a permanent magnet attached to the skin, is used by people worldwide for self-care. Despite a lack of established SMF dosage and treatment regimens, multiple studies are conducted to evaluate SMF therapy effectiveness. Our objectives in conducting this review are to: (i summarize SMF research conducted in humans; (ii critically evaluate reporting quality of SMF dosages and treatment parameters and (iii propose a set of criteria for reporting SMF treatment parameters in future clinical trials. We searched 27 electronic databases and reference lists. Only English language human studies were included. Excluded were studies of electromagnetic fields, transcranial magnetic stimulation, magnets placed on acupuncture points, animal studies, abstracts, posters and editorials. Data were extracted on clinical indication, study design and 10 essential SMF parameters. Three reviewers assessed quality of reporting and calculated a quality assessment score for each of the 10 treatment parameters. Fifty-six studies were reviewed, 42 conducted in patient populations and 14 in healthy volunteers. The SMF treatment parameters most often and most completely described were site of application, magnet support device and frequency and duration of application. Least often and least completely described were characteristics of the SMF: magnet dimensions, measured field strength and estimated distance of the magnet from the target tissue. Thirty-four (61% of studies failed to provide enough detail about SMF dosage to permit protocol replication by other investigators. Our findings highlight the need to optimize SMF dosing parameters for individual clinical conditions before proceeding to a full-scale clinical trial.

  16. Clinically relevant magnetic resonance imaging (MRI) findings in ...

    African Journals Online (AJOL)

    Background: Shoulder pain is the most common and well-documented site of musculoskeletal pain in elite swimmers. Structural abnormalities on magnetic resonance imaging (MRI) of elite swimmers' symptomatic shoulders are common. Little has been documented about the association between MRI findings in the ...

  17. Magnetized and collimated millimeter scale plasma jets with astrophysical relevance

    International Nuclear Information System (INIS)

    Brady, Parrish C.; Quevedo, Hernan J.; Valanju, Prashant M.; Bengtson, Roger D.; Ditmire, Todd

    2012-01-01

    Magnetized collimated plasma jets are created in the laboratory to extend our understanding of plasma jet acceleration and collimation mechanisms with particular connection to astrophysical jets. In this study, plasma collimated jets are formed from supersonic unmagnetized flows, mimicking a stellar wind, subject to currents and magnetohydrodynamic forces. It is found that an external poloidal magnetic field, like the ones found anchored to accretion disks, is essential to stabilize the jets against current-driven instabilities. The maximum jet length before instabilities develop is proportional to the field strength and the length threshold agrees well with Kruskal-Shafranov theory. The plasma evolution is modeled qualitatively using MHD theory of current-carrying flux tubes showing that jet acceleration and collimation arise as a result of electromagnetic forces.

  18. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nadejde, C., E-mail: claudia.nadejde@uaic.ro [Interdisciplinary Research Department – Field Science, ‘Alexandru Ioan Cuza’ University, Lascar Catargi 54, 700107 Iasi (Romania); Neamtu, M., E-mail: mariana.neamtu@uaic.ro [Interdisciplinary Research Department – Field Science, ‘Alexandru Ioan Cuza’ University, Lascar Catargi 54, 700107 Iasi (Romania); Schneider, R.J.; Hodoroaba, V.-D. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Ababei, G. [National Institute of Research and Development for Technical Physics, Dimitrie Mangeron Bd. 47, 700050 Iasi (Romania); Panne, U. [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin (Germany); Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin (Germany)

    2015-10-15

    Graphical abstract: - Highlights: • Non-hazardous, facile and inexpensive procedure for efficient wastewater treatment. • Chemical synthesis of ferrous oxalate modified Fe{sub 3}O{sub 4} nanoparticles. • Structural characterization confirmed the senzitized catalysts' nanometric size. • The highly magnetic catalysts can be easily recovered from solution. • 99.7% of azo dye was removed in 4 h using Fenton-like process in alkaline media. - Abstract: The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe{sub 3}O{sub 4}) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H{sub 2}O{sub 2} concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H{sub 2}O{sub 2} after 240 min of oxidation for a catalyst concentration of 10 g L{sup −1} at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  19. Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts

    Science.gov (United States)

    Nadejde, C.; Neamtu, M.; Schneider, R. J.; Hodoroaba, V.-D.; Ababei, G.; Panne, U.

    2015-10-01

    The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant under very mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, the surface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxide oxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L-1 at 25 °C and initial pH value of 9.0. CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment method for complete decolorization of effluents from textile dyeing and finishing processes, once the optimum operating conditions are established.

  20. Impulsive control of permanent magnet synchronous motors with parameters uncertainties

    International Nuclear Information System (INIS)

    Li Dong; Zhang Xiaohong; Wang Shilong; Yan Dan; Wang Hui

    2008-01-01

    The permanent magnet synchronous motors (PMSMs) may have chaotic behaviours for the uncertain values of parameters or under certain working conditions, which threatens the secure and stable operation of motor-driven. It is important to study methods of controlling or suppressing chaos in PMSMs. In this paper, robust stabilities of PMSM with parameter uncertainties are investigated. After the uncertain matrices which represent the variable system parameters are formulated through matrix analysis, a novel asymptotical stability criterion is established. Some illustrated examples are also given to show the effectiveness of the obtained results

  1. Using ANFIS for selection of more relevant parameters to predict dew point temperature

    International Nuclear Information System (INIS)

    Mohammadi, Kasra; Shamshirband, Shahaboddin; Petković, Dalibor; Yee, Por Lip; Mansor, Zulkefli

    2016-01-01

    Highlights: • ANFIS is used to select the most relevant variables for dew point temperature prediction. • Two cities from the central and south central parts of Iran are selected as case studies. • Influence of 5 parameters on dew point temperature is evaluated. • Appropriate selection of input variables has a notable effect on prediction. • Considering the most relevant combination of 2 parameters would be more suitable. - Abstract: In this research work, for the first time, the adaptive neuro fuzzy inference system (ANFIS) is employed to propose an approach for identifying the most significant parameters for prediction of daily dew point temperature (T_d_e_w). The ANFIS process for variable selection is implemented, which includes a number of ways to recognize the parameters offering favorable predictions. According to the physical factors influencing the dew formation, 8 variables of daily minimum, maximum and average air temperatures (T_m_i_n, T_m_a_x and T_a_v_g), relative humidity (R_h), atmospheric pressure (P), water vapor pressure (V_P), sunshine hour (n) and horizontal global solar radiation (H) are considered to investigate their effects on T_d_e_w. The used data include 7 years daily measured data of two Iranian cities located in the central and south central parts of the country. The results indicate that despite climate difference between the considered case studies, for both stations, V_P is the most influential variable while R_h is the least relevant element. Furthermore, the combination of T_m_i_n and V_P is recognized as the most influential set to predict T_d_e_w. The conducted examinations show that there is a remarkable difference between the errors achieved for most and less relevant input parameters, which highlights the importance of appropriate selection of input parameters. The use of more than two inputs may not be advisable and appropriate; thus, considering the most relevant combination of 2 parameters would be more suitable

  2. The relevance of the natural magnetic environment for life

    International Nuclear Information System (INIS)

    Morariu, V. Vasile

    2001-01-01

    Life on Earth evolved in a natural magnetic environment also known as the geomagnetic field (GMF). Since several decades it has been suggested that GMF and its variations may affect life. This became a more serious issue when it was suggested that mass extinction of species may have a connection with the GMF reversals. Such events involved exposure to possible large fluctuations but also to almost zero magnetic field (ZMF) for periods of say of at least hundreds of years. The present era of the space conquest also rise the interest for the behavior of life in conditions of ZMF since this is the characteristic of the interplanetary space. The strategy for investigation of the GMF role for terrestrial life is a) to look at the effects of the GMF fluctuations on various life related phenomena. This is a matter of correlating various statistical data (in the form of time series) and the corresponding time series for the geomagnetic activity and, b) to investigate in laboratory conditions the exposure of various species to ZMF conditions. While the first approach has the advantage that we may look into relatively long terms effects extending over several years or even tens of years, the second approach is limited to short term effects of days, weeks or several months at most. We use both types of approaches in our investigations. Our goal is twofold: 1) to identify the basic phenomena related to life which are influenced by ZMF and, 2) to sort out the species according to their sensitivity to ZMF. At present time we lack basic understanding of the role of GMF for life. According to our results, gathered for almost a decade of work, there is an inhibiting effect on the activity of some enzymes yet there are enzymes which are not sensitive to ZMF. We are trying to understand whether the conformation of some proteins or the kinetics of enzyme may change under such conditions. Among bacteria there is a clear diversity of responses as well as among various plant species but

  3. The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

    International Nuclear Information System (INIS)

    Ridzikova, A; Fronka, A.; Maly, B.; Moucka, L.

    2003-01-01

    In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222 Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

  4. Excitation of magnetic inhomogeneities in three-layer ferromagnetic structure with different parameters of the magnetic anisotropy and exchange

    Energy Technology Data Exchange (ETDEWEB)

    Ekomasov, E.G., E-mail: EkomasovEG@gmail.com [Bashkir State University, 32, Validy Str., Ufa, 450076 (Russian Federation); Murtazin, R.R. [Bashkir State University, 32, Validy Str., Ufa, 450076 (Russian Federation); Nazarov, V.N. [Institute of Molecule and Crystal Physics Ufa Research Centre of Russian Academy of Sciences, Prospekt Oktyabrya 151, Ufa, 450075 (Russian Federation)

    2015-07-01

    The generation and evolution of magnetic inhomogeneities, emerging in a thin flat layer with the parameters of the magnetic anisotropy and exchange interaction, with the parameters different from other two thick layers of the three-layer ferromagnetic structure, were investigated. The parameters ranges that determine the possibility of their existence were found. The possibility of the external magnetic field influence on the structure and dynamic properties of localized magnetic inhomogeneities was shown. - Highlights: • The generation of magnetic inhomogeneities in the three-layer ferromagnetic. • The influence of an external field on the parameters of magnetic inhomogeneities. • Numerical study of the structure and dynamics of magnetic inhomogeneities.

  5. Variation of Magnetic Field (By , Bz) Polarity and Statistical Analysis of Solar Wind Parameters during the Magnetic Storm Period

    OpenAIRE

    Ga-Hee Moon

    2011-01-01

    It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are ...

  6. The need for control of magnetic parameters for energy efficient performance of magnetic tunnel junctions

    Science.gov (United States)

    Farhat, I. A. H.; Gale, E.; Alpha, C.; Isakovic, A. F.

    2017-07-01

    Optimizing energy performance of Magnetic Tunnel Junctions (MTJs) is the key for embedding Spin Transfer Torque-Random Access Memory (STT-RAM) in low power circuits. Due to the complex interdependencies of the parameters and variables of the device operating energy, it is important to analyse parameters with most effective control of MTJ power. The impact of threshold current density, Jco , on the energy and the impact of HK on Jco are studied analytically, following the expressions that stem from Landau-Lifshitz-Gilbert-Slonczewski (LLGS-STT) model. In addition, the impact of other magnetic material parameters, such as Ms , and geometric parameters such as tfree and λ is discussed. Device modelling study was conducted to analyse the impact at the circuit level. Nano-magnetism simulation based on NMAGTM package was conducted to analyse the impact of controlling HK on the switching dynamics of the film.

  7. Safety analysis methodology with assessment of the impact of the prediction errors of relevant parameters

    International Nuclear Information System (INIS)

    Galia, A.V.

    2011-01-01

    The best estimate plus uncertainty approach (BEAU) requires the use of extensive resources and therefore it is usually applied for cases in which the available safety margin obtained with a conservative methodology can be questioned. Outside the BEAU methodology, there is not a clear approach on how to deal with the issue of considering the uncertainties resulting from prediction errors in the safety analyses performed for licensing submissions. However, the regulatory document RD-310 mentions that the analysis method shall account for uncertainties in the analysis data and models. A possible approach is presented, that is simple and reasonable, representing just the author's views, to take into account the impact of prediction errors and other uncertainties when performing safety analysis in line with regulatory requirements. The approach proposes taking into account the prediction error of relevant parameters. Relevant parameters would be those plant parameters that are surveyed and are used to initiate the action of a mitigating system or those that are representative of the most challenging phenomena for the integrity of a fission barrier. Examples of the application of the methodology are presented involving a comparison between the results with the new approach and a best estimate calculation during the blowdown phase for two small breaks in a generic CANDU 6 station. The calculations are performed with the CATHENA computer code. (author)

  8. Induction heating of rotating nonmagnetic billet in magnetic field produced by high-parameter permanent magnets

    Directory of Open Access Journals (Sweden)

    Ivo Doležel

    2014-04-01

    Full Text Available An advanced way of induction heating of nonmagnetic billets is discussed and modeled. The billet rotates in a stationary magnetic field produced by unmoving high-parameter permanent magnets fixed on magnetic circuit of an appropriate shape. The mathematical model of the problem consisting of two coupled partial differential equations is solved numerically, in the monolithic formulation. Computations are carried out using our own code Agros2D based on a fully adaptive higher-order finite element method. The most important results are verified experimentally on our own laboratory device.

  9. Method for extracting relevant electrical parameters from graphene field-effect transistors using a physical model

    International Nuclear Information System (INIS)

    Boscá, A.; Pedrós, J.; Martínez, J.; Calle, F.

    2015-01-01

    Due to its intrinsic high mobility, graphene has proved to be a suitable material for high-speed electronics, where graphene field-effect transistor (GFET) has shown excellent properties. In this work, we present a method for extracting relevant electrical parameters from GFET devices using a simple electrical characterization and a model fitting. With experimental data from the device output characteristics, the method allows to calculate parameters such as the mobility, the contact resistance, and the fixed charge. Differentiated electron and hole mobilities and direct connection with intrinsic material properties are some of the key aspects of this method. Moreover, the method output values can be correlated with several issues during key fabrication steps such as the graphene growth and transfer, the lithographic steps, or the metalization processes, providing a flexible tool for quality control in GFET fabrication, as well as a valuable feedback for improving the material-growth process

  10. Method for extracting relevant electrical parameters from graphene field-effect transistors using a physical model

    Energy Technology Data Exchange (ETDEWEB)

    Boscá, A., E-mail: alberto.bosca@upm.es [Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Dpto. de Ingeniería Electrónica, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Pedrós, J. [Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Campus de Excelencia Internacional, Campus Moncloa UCM-UPM, Madrid 28040 (Spain); Martínez, J. [Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Dpto. de Ciencia de Materiales, E.T.S.I de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Calle, F. [Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Dpto. de Ingeniería Electrónica, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, Madrid 28040 (Spain); Campus de Excelencia Internacional, Campus Moncloa UCM-UPM, Madrid 28040 (Spain)

    2015-01-28

    Due to its intrinsic high mobility, graphene has proved to be a suitable material for high-speed electronics, where graphene field-effect transistor (GFET) has shown excellent properties. In this work, we present a method for extracting relevant electrical parameters from GFET devices using a simple electrical characterization and a model fitting. With experimental data from the device output characteristics, the method allows to calculate parameters such as the mobility, the contact resistance, and the fixed charge. Differentiated electron and hole mobilities and direct connection with intrinsic material properties are some of the key aspects of this method. Moreover, the method output values can be correlated with several issues during key fabrication steps such as the graphene growth and transfer, the lithographic steps, or the metalization processes, providing a flexible tool for quality control in GFET fabrication, as well as a valuable feedback for improving the material-growth process.

  11. Parameter dependence of resonant spin torque magnetization reversal

    International Nuclear Information System (INIS)

    Fricke, L.; Serrano-Guisan, S.; Schumacher, H.W.

    2012-01-01

    We numerically study ultra fast resonant spin torque (ST) magnetization reversal in magnetic tunneling junctions (MTJ) driven by current pulses having a direct current (DC) and a resonant alternating current (AC) component. The precessional ST dynamics of the single domain MTJ free layer cell are modeled in the macro spin approximation. The energy efficiency, reversal time, and reversal reliability are investigated under variation of pulse parameters like direct and AC current amplitude, AC frequency and AC phase. We find a range of AC and direct current amplitudes where robust resonant ST reversal is obtained with faster switching time and reduced energy consumption per pulse compared to purely direct current ST reversal. However, for a certain range of AC and direct current amplitudes a strong dependence of the reversal properties on AC frequency and phase is found. Such regions of unreliable reversal must be avoided for ST memory applications.

  12. Parameter dependence of resonant spin torque magnetization reversal

    Science.gov (United States)

    Fricke, L.; Serrano-Guisan, S.; Schumacher, H. W.

    2012-04-01

    We numerically study ultra fast resonant spin torque (ST) magnetization reversal in magnetic tunneling junctions (MTJ) driven by current pulses having a direct current (DC) and a resonant alternating current (AC) component. The precessional ST dynamics of the single domain MTJ free layer cell are modeled in the macro spin approximation. The energy efficiency, reversal time, and reversal reliability are investigated under variation of pulse parameters like direct and AC current amplitude, AC frequency and AC phase. We find a range of AC and direct current amplitudes where robust resonant ST reversal is obtained with faster switching time and reduced energy consumption per pulse compared to purely direct current ST reversal. However, for a certain range of AC and direct current amplitudes a strong dependence of the reversal properties on AC frequency and phase is found. Such regions of unreliable reversal must be avoided for ST memory applications.

  13. [Influence of reverse osmosis concentrate on physicochemical parameters of Sini decoction material system and their relevance].

    Science.gov (United States)

    Jin, Tang-Hui; Zhang, Liu-Hong; Zhu, Hua-Xu; Guo, Li-Wei; Li, Bo; Lu, Ming-Ming

    2014-04-01

    By studying the process of reverse osmosis system for traditional Chinese medicine materials physicochemical parameters affecting the osmotic pressure of its relevance, new compound system reverse osmosis process design methods were explored. Three concentrations materials for high, middle and low were dubbed with Sini decoction as a model drug, and pretreated by 50 thousand relative molecular weight cut-off ultrafiltration membrane. The viscosity, turbidity, conductivity, salinity, TDS, pH value and osmotic pressure of each sample were determined after the reverse osmosis to study the physical and chemical parameters between their respective correlations with the osmotic pressure, and characterized by HPLC chromatograms showing changes before and after the main chemical composition of samples of reverse osmosis. Conductivity-osmotic pressure, salinity-osmotic pressure of the linear correlation coefficient, TDS-osmotic pressure between the three sets of parameters were 0.963 8, 0.932 7, 0.973 7, respectively. Reverse osmosis concentrate and its characteristic spectrum ultrafiltrate HPLC similarity were up to 0. 968 or more, except the low concentrations. There is a significant correlation between the three physicochemical parameters (conductivity, salinity, TDS) and osmotic pressure of each sample system, and there is also significant linear correlation between salinity, conductivity, TDS. The original chemical composition of Sini decoction material concentrate was completely remained after the process of reverse osmosis.

  14. Competing superconducting and magnetic order parameters and field-induced magnetism in electron doped Ba(Fe1-xCox)2As2

    DEFF Research Database (Denmark)

    Larsen, Jacob; Uranga, B. Mencia; Stieber, G.

    2015-01-01

    We have studied the magnetic and superconducting properties of Ba(Fe1-xCox)2As2 as a function of temperature and external magnetic field using neutron scattering and muon spin rotation. Below the superconducting transition temperature the magnetic and superconducting order parameters coexist...... and compete. A magnetic field can significantly enhance the magnetic scattering in the superconducting state, roughly doubling the Bragg intensity at 13.5 T. We perform a microscopic modelling of the data by use of a five-band Hamiltonian relevant to iron pnictides. In the superconducting state, vortices can...... slow down and freeze spin fluctuations locally. When such regions couple they result in a long-range ordered antiferromagnetic phase producing the enhanced magnetic elastic scattering in agreement with experiments....

  15. Parameters optimization for magnetic resonance coupling wireless power transmission.

    Science.gov (United States)

    Li, Changsheng; Zhang, He; Jiang, Xiaohua

    2014-01-01

    Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.

  16. Identification of Parameters in Active Magnetic Bearing Systems

    DEFF Research Database (Denmark)

    Lauridsen, Jonas Skjødt; Voigt, Andreas Jauernik; Mandrup-Poulsen, Christian

    2016-01-01

    A method for identifying uncertain parameters in Active Magnetic Bearing (AMB) based rotordynamic systems is introduced and adapted for experimental application. The Closed Loop Identification (CLI) method is utilised to estimate the current/force factors Ki and the displacement/force factors Ks...... as well as a time constant Τe for a first order approxima-tion of unknown actuator dynamics. To assess the precision with which CLI method can be employed to estimate AMBparameters the factors Ki, estimated using the CLI method, is compared to Ki factors attained through a Static Loading(SL) method....... The CLI method and SL method produce similar results, indicating that the CLI method is able to performclosed loop identification of uncertain AMB parameters....

  17. Outcome quality of in-patient cardiac rehabilitation in elderly patients--identification of relevant parameters.

    Science.gov (United States)

    Salzwedel, Annett; Nosper, Manfred; Röhrig, Bernd; Linck-Eleftheriadis, Sigrid; Strandt, Gert; Völler, Heinz

    2014-02-01

    Outcome quality management requires the consecutive registration of defined variables. The aim was to identify relevant parameters in order to objectively assess the in-patient rehabilitation outcome. From February 2009 to June 2010 1253 patients (70.9 ± 7.0 years, 78.1% men) at 12 rehabilitation clinics were enrolled. Items concerning sociodemographic data, the impairment group (surgery, conservative/interventional treatment), cardiovascular risk factors, structural and functional parameters and subjective health were tested in respect of their measurability, sensitivity to change and their propensity to be influenced by rehabilitation. The majority of patients (61.1%) were referred for rehabilitation after cardiac surgery, 38.9% after conservative or interventional treatment for an acute coronary syndrome. Functionally relevant comorbidities were seen in 49.2% (diabetes mellitus, stroke, peripheral artery disease, chronic obstructive lung disease). In three key areas 13 parameters were identified as being sensitive to change and subject to modification by rehabilitation: cardiovascular risk factors (blood pressure, low-density lipoprotein cholesterol, triglycerides), exercise capacity (resting heart rate, maximal exercise capacity, maximal walking distance, heart failure, angina pectoris) and subjective health (IRES-24 (indicators of rehabilitation status): pain, somatic health, psychological well-being and depression as well as anxiety on the Hospital Anxiety and Depression Scale). The outcome of in-patient rehabilitation in elderly patients can be comprehensively assessed by the identification of appropriate key areas, that is, cardiovascular risk factors, exercise capacity and subjective health. This may well serve as a benchmark for internal and external quality management.

  18. Repetitive transcranial magnetic stimulator with controllable pulse parameters

    Science.gov (United States)

    Peterchev, Angel V.; Murphy, David L.; Lisanby, Sarah H.

    2011-06-01

    The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.

  19. Pulsed air-core deflector-magnet design parameters

    International Nuclear Information System (INIS)

    Jason, A.J.; Cooper, R.K.; Liebman, A.D.; Blind, B.; Koelle, A.R.

    1983-01-01

    The response of air-core magnets to pulsed excitation is dependent on the pulse frequency spectrum because of fields produced by induced currents in the magnet structure. We discuss this phenomenon quantitatively in terms of magnet performance optimization

  20. Integrating retention soil filters into urban hydrologic models - Relevant processes and important parameters

    Science.gov (United States)

    Bachmann-Machnik, Anna; Meyer, Daniel; Waldhoff, Axel; Fuchs, Stephan; Dittmer, Ulrich

    2018-04-01

    Retention Soil Filters (RSFs), a form of vertical flow constructed wetlands specifically designed for combined sewer overflow (CSO) treatment, have proven to be an effective tool to mitigate negative impacts of CSOs on receiving water bodies. Long-term hydrologic simulations are used to predict the emissions from urban drainage systems during planning of stormwater management measures. So far no universally accepted model for RSF simulation exists. When simulating hydraulics and water quality in RSFs, an appropriate level of detail must be chosen for reasonable balancing between model complexity and model handling, considering the model input's level of uncertainty. The most crucial parameters determining the resultant uncertainties of the integrated sewer system and filter bed model were identified by evaluating a virtual drainage system with a Retention Soil Filter for CSO treatment. To determine reasonable parameter ranges for RSF simulations, data of 207 events from six full-scale RSF plants in Germany were analyzed. Data evaluation shows that even though different plants with varying loading and operation modes were examined, a simple model is sufficient to assess relevant suspended solids (SS), chemical oxygen demand (COD) and NH4 emissions from RSFs. Two conceptual RSF models with different degrees of complexity were assessed. These models were developed based on evaluation of data from full scale RSF plants and column experiments. Incorporated model processes are ammonium adsorption in the filter layer and degradation during subsequent dry weather period, filtration of SS and particulate COD (XCOD) to a constant background concentration and removal of solute COD (SCOD) by a constant removal rate during filter passage as well as sedimentation of SS and XCOD in the filter overflow. XCOD, SS and ammonium loads as well as ammonium concentration peaks are discharged primarily via RSF overflow not passing through the filter bed. Uncertainties of the integrated

  1. Nonthermal plasmas around black holes, relevant collective modes, new configurations, and magnetic field amplification

    Energy Technology Data Exchange (ETDEWEB)

    Coppi, B., E-mail: coppi@mit.edu [Massachusetts Institute of Technology (United States)

    2017-03-15

    The radiation emission from Shining Black Holes is most frequently observed to have nonthermal features. It is therefore appropriate to consider relevant collective processes in plasmas surrounding black holes that contain high energy particles with nonthermal distributions in momentum space. A fluid description with significant temperature anisotropies is the simplest relevant approach. These anisotropies are shown to have a critical influence on: (a) the existence and characteristics of stationary plasma and field ring configurations, (b) the excitation of “thermo-gravitational modes” driven by temperature anisotropies and gradients that involve gravity and rotation, (c) the generation of magnetic fields over macroscopic scale distances, and (d) the transport of angular momentum.

  2. Some relevant parameters for assessing fire hazards of combustible mine materials using laboratory scale experiments.

    Science.gov (United States)

    Litton, Charles D; Perera, Inoka E; Harteis, Samuel P; Teacoach, Kara A; DeRosa, Maria I; Thomas, Richard A; Smith, Alex C

    2018-04-15

    When combustible materials ignite and burn, the potential for fire growth and flame spread represents an obvious hazard, but during these processes of ignition and flaming, other life hazards present themselves and should be included to ensure an effective overall analysis of the relevant fire hazards. In particular, the gases and smoke produced both during the smoldering stages of fires leading to ignition and during the advanced flaming stages of a developing fire serve to contaminate the surrounding atmosphere, potentially producing elevated levels of toxicity and high levels of smoke obscuration that render the environment untenable. In underground mines, these hazards may be exacerbated by the existing forced ventilation that can carry the gases and smoke to locations far-removed from the fire location. Clearly, materials that require high temperatures (above 1400 K) and that exhibit low mass loss during thermal decomposition, or that require high heat fluxes or heat transfer rates to ignite represent less of a hazard than materials that decompose at low temperatures or ignite at low levels of heat flux. In order to define and quantify some possible parameters that can be used to assess these hazards, small-scale laboratory experiments were conducted in a number of configurations to measure: 1) the toxic gases and smoke produced both during non-flaming and flaming combustion; 2) mass loss rates as a function of temperature to determine ease of thermal decomposition; and 3) mass loss rates and times to ignition as a function of incident heat flux. This paper describes the experiments that were conducted, their results, and the development of a set of parameters that could possibly be used to assess the overall fire hazard of combustible materials using small scale laboratory experiments.

  3. Review of NB3 SN magnets completed or under manufacture and relevant for future fusion magnets

    International Nuclear Information System (INIS)

    Poehlchen, R.

    1992-05-01

    Nb 3 Sn magnets make use of a forced flow of helium in the longitudinal direction through the individual conductor. The well established vacuum-pressure-impregnation process can be employed in order to achieve a mechanically monolithic winding pack with a highly reliable electric insulation with a high electric strength of 20 KV and above. This is of crucial importance for the Poloidal Coils in normal operation already, but even more important in case of a fast discharge of the Poloidal Coil system or the Toroidal Coil system. The higher the acceptable dump voltage is, the faster the discharge can be thus, making it easier to keep hot spot temperatures at acceptable levels. (author)

  4. Microscopic interplay of superconducting and magnetic order parameters in ferropnictides

    Energy Technology Data Exchange (ETDEWEB)

    Maeter, H.; Goltz, T.; Spehling, J.; Klauss, H.H. [Institut fuer Festkoerperphysik, TU Dresden (Germany); Bendele, M.; Luetkens, H.; Khasanov, R.; Pascua, G.; Shermadini, Z.; Amato, A. [Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, Villigen (Switzerland); Aswartham, S.; Hamann-Borrero, J.E.; Kondrat, A.; Hess, C.; Wolter, A.; Wurmehl, S.; Behr, G.; Buechner, B. [Leibniz-Institut fuer Festkoerper- und Werkstoffforschung Dresden (Germany); Wiesenmayer, E.; Johrendt, D. [Department Chemie, Ludwig-Maximilians-Universitaet Muenchen (Germany); Potts, H.; Banusch, B. [Swiss Nanoscience Institute, Universitaet Basel (Switzerland)

    2012-07-01

    We present results of {mu}SR experiments of Ba{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} that show a large coupling of the superconducting and magnetic order parameters. This is unexpected in light of the phase separation in Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2}. However, in a {mu}SR study of Ba{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} we unambiguously showed microscopic coexistence, even though there are many reports of phase separation in this system. In FeSe{sub 1-x} the interplay of phase separation and microscopic coexistence is also evident, here pressure can induce a change from microscopic coexistence to a combination of both. In light of the {mu}SR results it seems likely that phase separation and microscopic coexistence depend on the microscopic properties much more than on disorder.

  5. Modelling of interplanetary pickup ion fluxes and relevance for LISM parameters

    International Nuclear Information System (INIS)

    Fahr, H.J.; Rucinski, D.

    1989-01-01

    It has been known for many years that neutral interstellar atoms enter the solar system from the upwind side and penetrate deep into the inner heliosphere. Helium atoms, in particular, advance towards very small solar distances before they are ionized and then again convected as He - pickup ions outwards with the solar wind. Since these ions were recently detected in space, we concentrate here on calculations of He + production rates and He + fluxes. It is shown that inside 1 a.u., the He - production is essentially determined both by solar e.u.v. photoionization and by electron impact ionization. We calculate He + production rates as a function of space coordinates, taking into account the core-halo structure of the energy distribution of solar wind electrons and their temperature distribution with distance according to relevant solar wind models. For this purpose, a newly developed program to compute He densities was used. In contrast to the production of H + , the He - production rates are found to be higher on the downwind axis than on the upwind axis by a factor of 5. We also determine partial and total He + ion fluxes as a function of solar distance and longitude. It is interesting to note that only the values for total fluxes agree well with the integrated He + fluxes measured by the SULEICA experiment aboard the AMPTE satellite. This indicates that pickup ions under the influence of the intrinsic MHD wave turbulence in the solar wind change their primary seed distribution function by rapid pitch-angle scattering and subsequent adiabatic cooling. To interpret the He + intensity profile along the orbit of the Earth in terms of LISM helium parameters, we point to the need to take into account carefully electron impact ionization in order to prevent misinterpretations. (author)

  6. A dynamic macromodel for distributed parameter magnetic microactuators

    International Nuclear Information System (INIS)

    Fang Yuming; Huang Qingan; Li Weihua

    2008-01-01

    This paper presents a reduced-order model to describe the mechanical behaviour of microbeam-based magnetic devices. The integration for magnetic force is calculated by dividing the microbeam into several segments, and the nonlinear equation set has been developed based on the magnetic circuit principle. In comparison with previous models, the present macromodel accounts for both the micro-magnetic-core reluctance and the coupling between the beam deflection and magnetic force. This macromodel is validated by comparing with the experimental results available in some papers and finite-element solutions

  7. Synthesis of Co/Co3O4 Nanocomposite Particles Relevant to Magnetic Field Processing

    DEFF Research Database (Denmark)

    Srivastava, A.K.; Madhavi, S.; Menon, Mohan

    2010-01-01

    Co/Co3O4 nanocomposite particles of various morphologies were synthesized by the reverse micelle technique. Equiaxed, rod and faceted crystals with rectangular, pentagonal and hexagonal cross sections were observed. Annealing resulted in the formation of a composite of cobalt oxide (Co3O4) and fc...... cobalt (Co). Removal of boron residues from the final product was established by surface characterization. Magnetic moment of these nanocomposite particles is relevant to magnetic field processing.......Co/Co3O4 nanocomposite particles of various morphologies were synthesized by the reverse micelle technique. Equiaxed, rod and faceted crystals with rectangular, pentagonal and hexagonal cross sections were observed. Annealing resulted in the formation of a composite of cobalt oxide (Co3O4) and fcc...

  8. Graphite structure and magnetic parameters of flake graphite cast iron

    Czech Academy of Sciences Publication Activity Database

    Vértesy, G.; Uchimoto, T.; Takagi, T.; Tomáš, Ivan; Kage, H.

    2017-01-01

    Roč. 442, Nov (2017), s. 397-402 ISSN 0304-8853 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:68378271 Keywords : magnetic NDE * magnetic adaptive testing * cast iron * graphite structure * pearlite content Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.630, year: 2016

  9. Application of all relevant feature selection for failure analysis of parameter-induced simulation crashes in climate models

    Science.gov (United States)

    Paja, W.; Wrzesień, M.; Niemiec, R.; Rudnicki, W. R.

    2015-07-01

    The climate models are extremely complex pieces of software. They reflect best knowledge on physical components of the climate, nevertheless, they contain several parameters, which are too weakly constrained by observations, and can potentially lead to a crash of simulation. Recently a study by Lucas et al. (2013) has shown that machine learning methods can be used for predicting which combinations of parameters can lead to crash of simulation, and hence which processes described by these parameters need refined analyses. In the current study we reanalyse the dataset used in this research using different methodology. We confirm the main conclusion of the original study concerning suitability of machine learning for prediction of crashes. We show, that only three of the eight parameters indicated in the original study as relevant for prediction of the crash are indeed strongly relevant, three other are relevant but redundant, and two are not relevant at all. We also show that the variance due to split of data between training and validation sets has large influence both on accuracy of predictions and relative importance of variables, hence only cross-validated approach can deliver robust prediction of performance and relevance of variables.

  10. Application of all-relevant feature selection for the failure analysis of parameter-induced simulation crashes in climate models

    Science.gov (United States)

    Paja, Wiesław; Wrzesien, Mariusz; Niemiec, Rafał; Rudnicki, Witold R.

    2016-03-01

    Climate models are extremely complex pieces of software. They reflect the best knowledge on the physical components of the climate; nevertheless, they contain several parameters, which are too weakly constrained by observations, and can potentially lead to a simulation crashing. Recently a study by Lucas et al. (2013) has shown that machine learning methods can be used for predicting which combinations of parameters can lead to the simulation crashing and hence which processes described by these parameters need refined analyses. In the current study we reanalyse the data set used in this research using different methodology. We confirm the main conclusion of the original study concerning the suitability of machine learning for the prediction of crashes. We show that only three of the eight parameters indicated in the original study as relevant for prediction of the crash are indeed strongly relevant, three others are relevant but redundant and two are not relevant at all. We also show that the variance due to the split of data between training and validation sets has a large influence both on the accuracy of predictions and on the relative importance of variables; hence only a cross-validated approach can deliver a robust prediction of performance and relevance of variables.

  11. How to Select the most Relevant Roughness Parameters of a Surface: Methodology Research Strategy

    Science.gov (United States)

    Bobrovskij, I. N.

    2018-01-01

    In this paper, the foundations for new methodology creation which provides solving problem of surfaces structure new standards parameters huge amount conflicted with necessary actual floors quantity of surfaces structure parameters which is related to measurement complexity decreasing are considered. At the moment, there is no single assessment of the importance of a parameters. The approval of presented methodology for aerospace cluster components surfaces allows to create necessary foundation, to develop scientific estimation of surfaces texture parameters, to obtain material for investigators of chosen technological procedure. The methods necessary for further work, the creation of a fundamental reserve and development as a scientific direction for assessing the significance of microgeometry parameters are selected.

  12. Magnetic phase transitions with incommensurate structures in systems with coupled order parameters

    International Nuclear Information System (INIS)

    Izyumov, Yu.A.; Laptev, V.M.; Petrov, S.B.

    1984-01-01

    Modulated magnetic phases are investigated for the case when symmetry does not allow linear by gradients Lifshits invariants and magnetic momenta are converted by two irreducible representations. Possible phase diagrams with participation of incommensurable phases are plotted on the base of Ginsburg-Landau functional for 2 bound parameters of the order. The role of the highest harmonics in spatial distribution of the order parameters is clarified on the example of magnetic phase transitions in Er

  13. Bayesian estimation of multicomponent relaxation parameters in magnetic resonance fingerprinting.

    Science.gov (United States)

    McGivney, Debra; Deshmane, Anagha; Jiang, Yun; Ma, Dan; Badve, Chaitra; Sloan, Andrew; Gulani, Vikas; Griswold, Mark

    2018-07-01

    To estimate multiple components within a single voxel in magnetic resonance fingerprinting when the number and types of tissues comprising the voxel are not known a priori. Multiple tissue components within a single voxel are potentially separable with magnetic resonance fingerprinting as a result of differences in signal evolutions of each component. The Bayesian framework for inverse problems provides a natural and flexible setting for solving this problem when the tissue composition per voxel is unknown. Assuming that only a few entries from the dictionary contribute to a mixed signal, sparsity-promoting priors can be placed upon the solution. An iterative algorithm is applied to compute the maximum a posteriori estimator of the posterior probability density to determine the magnetic resonance fingerprinting dictionary entries that contribute most significantly to mixed or pure voxels. Simulation results show that the algorithm is robust in finding the component tissues of mixed voxels. Preliminary in vivo data confirm this result, and show good agreement in voxels containing pure tissue. The Bayesian framework and algorithm shown provide accurate solutions for the partial-volume problem in magnetic resonance fingerprinting. The flexibility of the method will allow further study into different priors and hyperpriors that can be applied in the model. Magn Reson Med 80:159-170, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  14. Finding Relevant Parameters for the Thin-film Photovoltaic Cells Production Process with the Application of Data Mining Methods.

    Science.gov (United States)

    Ulaczyk, Jan; Morawiec, Krzysztof; Zabierowski, Paweł; Drobiazg, Tomasz; Barreau, Nicolas

    2017-09-01

    A data mining approach is proposed as a useful tool for the control parameters analysis of the 3-stage CIGSe photovoltaic cell production process, in order to find variables that are the most relevant for cell electric parameters and efficiency. The analysed data set consists of stage duration times, heater power values as well as temperatures for the element sources and the substrate - there are 14 variables per sample in total. The most relevant variables of the process have been found based on the so-called random forest analysis with the application of the Boruta algorithm. 118 CIGSe samples, prepared at Institut des Matériaux Jean Rouxel, were analysed. The results are close to experimental knowledge on the CIGSe cells production process. They bring new evidence to production parameters of new cells and further research. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Parameters for calculation of nuclear reactions of relevance to non-energy nuclear applications (Reference Input Parameter Library: Phase III). Summary report of the first research coordination meeting

    International Nuclear Information System (INIS)

    Capote Noy, R.

    2004-08-01

    A summary is given of the First Research Coordination Meeting on Parameters for Calculation of Nuclear Reactions of Relevance to Non-Energy Nuclear Applications (Reference Input Parameter Library: Phase III), including a critical review of the RIPL-2 file. The new library should serve as input for theoretical calculations of nuclear reaction data at incident energies up to 200 MeV, as needed for energy and non-energy modern applications of nuclear data. Technical discussions and the resulting work plan of the Coordinated Research Programme are summarized, along with actions and deadlines. Participants' contributions to the RCM are also attached. (author)

  16. Sheath and plasma parameters in a magnetized plasma system

    Indian Academy of Sciences (India)

    through the negatively biased grid from the source region into the diffused region. It is observed that the electron temperature increases with the magnetic field in the diffused region whereas it decreases in the source region of the system for a constant grid biasing voltage. Also, investigation is done to see the change of ...

  17. Extraction and derivatization of chemical weapons convention relevant aminoalcohols on magnetic cation-exchange resins.

    Science.gov (United States)

    Singh, Varoon; Garg, Prabhat; Chinthakindi, Sridhar; Tak, Vijay; Dubey, Devendra Kumar

    2014-02-14

    Analysis and identification of nitrogen containing aminoalcohols is an integral part of the verification analysis of chemical weapons convention (CWC). This study was aimed to develop extraction and derivatization of aminoalcohols of CWC relevance by using magnetic dispersive solid-phase extraction (MDSPE) in combination with on-resin derivatization (ORD). For this purpose, sulfonated magnetic cation-exchange resins (SMRs) were prepared using magnetite nanoparticles as core, styrene and divinylbenzene as polymer coat and sulfonic acid as acidic cation exchanger. SMRs were successfully employed as extractant for targeted basic analytes. Adsorbed analytes were derivatized with hexamethyldisilazane (HMDS) on the surface of extractant. Derivatized (silylated) compounds were analyzed by GC-MS in SIM and full scan mode. The linearity of the method ranged from 5 to 200ngmL(-1). The LOD and LOQ ranged from 2 to 6ngmL(-1) and 5 to 19ngmL(-1) respectively. The relative standard deviation for intra-day repeatability and inter-day intermediate precision ranged from 5.1% to 6.6% and 0.2% to 7.6% respectively. Recoveries of analytes from spiked water samples from different sources varied from 28.4% to 89.3%. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Analysis of all dimensionful parameters relevant in gravitational dressing of conformal theories

    International Nuclear Information System (INIS)

    Dorn, H.; Otto, H.J.

    1992-01-01

    Starting from a covariant and background independent definition of normal ordered vertex operators we give an alternative derivation of the KPZ relation between conformal dimensions and their gravitational dressed partners. With our method we are able to study for arbitrary genus the dependence of N-point functions on all dimensionful parameters. Implications for the interpretation of gravitational dressed dimensions are discussed. (orig.)

  19. Evaluation of parameter sensitivities for flux-switching permanent magnet machines based on simplified equivalent magnetic circuit

    Directory of Open Access Journals (Sweden)

    Gan Zhang

    2017-05-01

    Full Text Available Most of the published papers regarding the design of flux-switching permanent magnet machines are focused on the analysis and optimization of electromagnetic or mechanical behaviors, however, the evaluate of the parameter sensitivities have not been covered, which contrarily, is the main contribution of this paper. Based on the finite element analysis (FEA and simplified equivalent magnetic circuit, the method proposed in this paper enables the influences of parameters on the electromagnetic performances, i.e. the parameter sensitivities, to be given by equations. The FEA results are also validated by experimental measurements.

  20. Understanding Magnetic Resonance Imaging of Knee Cartilage Repair: A Focus on Clinical Relevance.

    Science.gov (United States)

    Hayashi, Daichi; Li, Xinning; Murakami, Akira M; Roemer, Frank W; Trattnig, Siegfried; Guermazi, Ali

    2017-06-01

    The aims of this review article are (a) to describe the principles of morphologic and compositional magnetic resonance imaging (MRI) techniques relevant for the imaging of knee cartilage repair surgery and their application to longitudinal studies and (b) to illustrate the clinical relevance of pre- and postsurgical MRI with correlation to intraoperative images. First, MRI sequences that can be applied for imaging of cartilage repair tissue in the knee are described, focusing on comparison of 2D and 3D fast spin echo and gradient recalled echo sequences. Imaging features of cartilage repair tissue are then discussed, including conventional (morphologic) MRI and compositional MRI techniques. More specifically, imaging techniques for specific cartilage repair surgery techniques as described above, as well as MRI-based semiquantitative scoring systems for the knee cartilage repair tissue-MR Observation of Cartilage Repair Tissue and Cartilage Repair OA Knee Score-are explained. Then, currently available surgical techniques are reviewed, including marrow stimulation, osteochondral autograft, osteochondral allograft, particulate cartilage allograft, autologous chondrocyte implantation, and others. Finally, ongoing research efforts and future direction of cartilage repair tissue imaging are discussed.

  1. Influence of the particle parameters on the stability of magnetic dopants in a ferrolyotropic suspension

    Energy Technology Data Exchange (ETDEWEB)

    Appel, Ingo; Behrens, Silke [Institut für Katalyseforschung und -technologie, Karlsruher Institut für Technologie (KIT), Postfach 3640, 76021 Karlsruhe (Germany); Anorganisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany)

    2017-06-01

    The doping of liquid crystals with magnetic nanoparticles increases the magnetic susceptibility and the sensitivity to small magnetic fields. This offers interesting possibilities for controlling optical properties via external magnetic fields. The stabilization of magnetic nanoparticles in the liquid crystalline host, however, is challenging, since magnetic dipolar interactions and LC-mediated forces may result in their aggregation and even phase separation. So far, only few groups have investigated the long-term stability of these systems. In the present study, a set of magnetic iron oxide nanoparticles with different particle size, shape and surface properties was synthesized by thermal decomposition or co-precipitation. The magnetic nanoparticles were further integrated in a model liquid crystalline host (i.e., the lyotropic system potassium laurate/1-decanol/water) to investigate the effect of the different particle parameters on the stability of the resulting ferrolyotrope.

  2. Measurements of relevant parameters in the formation of clathrate hydrates by a novel experimental apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Arca, S.; Di Profio, P.; Germani, R.; Savelli, G. [Perugia Univ., CEMIN, Perugia (Italy). Dept. of Chemistry

    2008-07-01

    There is a growing interest in understanding the thermodynamics and kinetics of clathrate hydrate formation. This paper presented a study that involved the design, construction, calibration, and testing of a new apparatus that could obtain as many parameters as possible in a single formation batch and that could measure unexplored clathrate hydrate parameters. The apparatus was capable of measuring equilibrium phases involving gaseous components. The paper described the conceptual design as well as the chamber, pressure line, temperature control, liquid addition line, and conductometric probe. The paper also discussed data acquisition, stirring, measurement examples, and internal illumination and video monitoring. It was concluded that refining measurements, particularly those concerning kinetic characterizations, is important in order to clarify several uncertain kinetic behaviors of clathrate hydrates. 6 refs., 16 figs.

  3. Status report [Parameters for calculation of nuclear reactions of relevance to non-energy nuclear applications

    International Nuclear Information System (INIS)

    Koning, A.

    2008-01-01

    Full text: Masses: Adopted Goriely HFB masses in TALYS as theoretical default instead of Moeller. Audi-Wapstra, Moeller and HFB masses tested formally with TALYS. Levels. Adopted latest discrete level update (2006) by Belgya (as sent by Capote) in TALYS. Tested with TALYS. Resonances. Adopted RIPL-2 D0 collection in TALYS. Tested by TALYS. Optical model. Coordinated Optical model segment for RIPL-3. Adopted Soukhovitskii CC potential as default for actinides. Covariances: Confirmed OMP parameter uncertainties from last meeting. Level density. Produced consistent set of level density parameters for CTM, BFM, GSM and HFM. Local models (per nucleus) and global models (systematics). With and without effective collective enhancement. Included and tested with TALYS Gamma-ray strength. Adopted Goriely HFB strength function tables as option (not default) in TALYS. Both formally tested and validated with TALYS. Fission. Adopted Sin-Capote WKB approximation in TALYS as option for fission calculations. Formally tested. RIPL-2/3 validation. Very extensive formal tests and validation procedures with TALYS. MONKEY code for random input files (has found RIPL errors in the past). Automatic comparison with all available EXFOR cross section data (for level density study). Started work on global parameter uncertainties (for covariances). SALTY nuclear data library (final version under construction): - 60 MeV n,g,p,d,t,h,a activation files for 1200 nuclides - 200 MeV n,g,p,d,t,h,a transport files for 250 nuclides RIPL is automatically being used by all TALYS users (and TALYS-related publications). TALYS-1.0 release in December 2007 (delay because of level densities). (author)

  4. Microwave generation for magnetic fusion energy applications: Task A -- Experimental and numerical study of microwave sources for ECRH incorporating depressed collectors and with ITER-relevant parameters, and Task B -- Theory and modeling of high frequency, high power gyrotron operation. Final report, July 15, 1994--July 14, 1995

    International Nuclear Information System (INIS)

    1995-01-01

    A proof-of-principle short pulse (∼ 100 ns) experiment has successfully demonstrated operation of a sheet-beam FEL amplifier with output power of 250 kW at 86 Ghz and with 24 dB saturated gain and ∼ 3% efficiency. Gain in the linear region was 30 dB. Measured performance parameters were in good agreement with predictions of a multi-mode, time dependence code. Also, a code has been developed to design depressed collectors which will enhance efficiency of ECRH sources (both FELs and gyrotrons). Extensive analytical and theoretical work in support of high power gyrotron development at Varian and MIT, and in support of ITER has been carried out. Specific studies are described. The effect of beam quality on the operation of the 145 GHz gyrotrons at MIT has been characterized using experimentally measured beam velocity distribution functions. The observed performance of these devices is consistent with a 10% RMS perpendicular velocity spread. An extensive study of mode competition in the 110 GHZ experiments at Varian and MIT has been carried out. Design criteria for the suppression of parasitic modes have been given for these experiments. The issues of mode competition and beam quality in the proposed 170 GHz megawatt gyrotrons for ITER have been investigated. Designs of cavities which eliminate unwanted modes have been made, and their sensitivity to beam quality studied. The constraints of lower power density and absence of mode competition coupled with the anticipated beam quality restrict efficiency. Efficiency can be improved by increasing the power density in the wall, improving beam quality, or perhaps by using a more advanced cavity. Studies of the causes of velocity spread in MIG guns have been initiated. Further, the effect of beam cavity misalignment on mode competition has been addressed

  5. Determination of toroidal equilibrium parameters from magnetic probe measurements

    International Nuclear Information System (INIS)

    Brynolf, J.; Eriksson, H.G.; Persson, H.; Hellblom, G.

    1992-12-01

    A method has been developed by which the poloidal flux function in the vacuum region between the plasma and the external conductors (and the iron core) can be deduced from external magnetic field measurements. The plasma is in equilibrium and the solution is restricted to plasmas without irregularities. The poloidal field components Bθ and B r are measured at different poloidal positions outside the liner and modelled by truncated Fourier series. The Grad-Shafranov equation in the vacuum region is then solved with these modelled values of Bθ and B r as boundary conditions. (authors)

  6. Atlas selection for hippocampus segmentation: Relevance evaluation of three meta-information parameters.

    Science.gov (United States)

    Dill, Vanderson; Klein, Pedro Costa; Franco, Alexandre Rosa; Pinho, Márcio Sarroglia

    2018-04-01

    Current state-of-the-art methods for whole and subfield hippocampus segmentation use pre-segmented templates, also known as atlases, in the pre-processing stages. Typically, the input image is registered to the template, which provides prior information for the segmentation process. Using a single standard atlas increases the difficulty in dealing with individuals who have a brain anatomy that is morphologically different from the atlas, especially in older brains. To increase the segmentation precision in these cases, without any manual intervention, multiple atlases can be used. However, registration to many templates leads to a high computational cost. Researchers have proposed to use an atlas pre-selection technique based on meta-information followed by the selection of an atlas based on image similarity. Unfortunately, this method also presents a high computational cost due to the image-similarity process. Thus, it is desirable to pre-select a smaller number of atlases as long as this does not impact on the segmentation quality. To pick out an atlas that provides the best registration, we evaluate the use of three meta-information parameters (medical condition, age range, and gender) to choose the atlas. In this work, 24 atlases were defined and each is based on the combination of the three meta-information parameters. These atlases were used to segment 352 vol from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Hippocampus segmentation with each of these atlases was evaluated and compared to reference segmentations of the hippocampus, which are available from ADNI. The use of atlas selection by meta-information led to a significant gain in the Dice similarity coefficient, which reached 0.68 ± 0.11, compared to 0.62 ± 0.12 when using only the standard MNI152 atlas. Statistical analysis showed that the three meta-information parameters provided a significant improvement in the segmentation accuracy. Copyright © 2018 Elsevier Ltd

  7. Ginsburg-Landau theory of two antagonistic order parameters: magnetism and superconductivity

    International Nuclear Information System (INIS)

    Suhl, H.

    1978-01-01

    An attempt is made to construct a Ginsburg-Landau theory of so-called magnetic superconductors. Two order parameters, the magnetization field and the gap function, are introduced in such a way as to inhibit each others growth. It is found that the non-local character of the superconducting order parameter must be taken into account in any evaluation of effects of the critical magnetic fluctuations. Some predictions are made within the limits of Ornstein-Zoernicke-like fluctuation theory and some comparison is made with available data. (Auth.)

  8. Combination of magnetic parameters: an efficient way to discriminate soil-contamination sources (south France)

    International Nuclear Information System (INIS)

    Lecoanet, H.; Leveque, F.; Ambrosi, J.-P.

    2003-01-01

    Biplots combining magnetic parameters allow identification of different pollutant emission sources. - Biplots combining magnetic parameters allow to identification and differentiation different pollutant emission sources. A major problem in soil pollution is the characterization of the relative contributions of different anthropogenic particles sources. This paper demonstrates the efficiency of magnetic techniques to provide identification and differentiation of contaminating emission sources. About 100 soil samples were collected across a mixed agricultural and industrial area (Crau plain/Berre-Fos basin) in southern France. Nine soil profiles were realized. They are aligned along a transect, from the Mediterranean cost to the north. Measurements of initial magnetic susceptibility (χ) and remanent magnetization (ARM, IRM) have been carried out at room temperature. Several ratios of magnetic parameters were calculated and tested. Bivariate analyses allow to characterize different pollution sources and graphic results suggest three dominant contributions originated from road traffic, airport and steel industry. Moreover, magnetic grain-size discrimination between surface-soil samples and bottom-soil samples is obtained. An increase of hard magnetic components from topsoil towards the bottom of the profiles is evidenced

  9. Design approaches and parameters for magnetically levitated transport systems

    International Nuclear Information System (INIS)

    Danby, G.T.; Powell, J.R.

    1988-01-01

    Mechanically levitated transport system approaches are assessed with regard to thrust power needs, track cost, suspension stability, and safety. The null flux suspension appears as the favored approach, having the least thrust power requirements, highest stability, and lowest amount of track material. Various null flux configurations are described, together with operating parameters. The Linear Synchronous Motor (LSM) propulsion system is also described for propelling the suspended vehicles. Cryogenics and superconductivity aspects are discussed and the effect of high T/sub c/ superconductors evaluated

  10. Inverse analyses of effective diffusion parameters relevant for a two-phase moisture model of cementitious materials

    DEFF Research Database (Denmark)

    Addassi, Mouadh; Johannesson, Björn; Wadsö, Lars

    2018-01-01

    Here we present an inverse analyses approach to determining the two-phase moisture transport properties relevant to concrete durability modeling. The purposed moisture transport model was based on a continuum approach with two truly separate equations for the liquid and gas phase being connected...... test, and, (iv) capillary suction test. Mass change over time, as obtained from the drying test, the two different cup test intervals and the capillary suction test, was used to obtain the effective diffusion parameters using the proposed inverse analyses approach. The moisture properties obtained...

  11. Magnetic Parameters Of A NB3SN Superconducting Magnet For A 56 HGz ECR Ion Source

    International Nuclear Information System (INIS)

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C.M.; Prestemon, S.; Sabbi, G.L.; Todd, D.S.

    2009-01-01

    Third generation Electron Cyclotron Resonance (ECR) ion sources operate at microwave frequencies between 20 and 30 GHz and employ NbTi superconducting magnets with a conductor peak field of 6-7 T. A significant gain in performance can be achieved by replacing NbTi with Nb 3 Sn, allowing solenoids and sextupole coils to reach a field of 15 T in the windings. In this paper we describe the design of a Nb 3 Sn superconducting magnet for a fourth generation ECR source operating at a microwave frequency of 56 GHz. The magnet design features a configuration with an internal sextupole magnet surrounded by three solenoids. A finite element magnetic model has been used to investigate conductor peak fields and the operational margins. Results of the numerical analysis are presented and discussed.

  12. MAGNETIC PARAMETERS OF A NB3SN SUPERCONDUCTING MAGNET FOR A 56 HGz ECR ION SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2009-05-04

    Third generation Electron Cyclotron Resonance (ECR) ion sources operate at microwave frequencies between 20 and 30 GHz and employ NbTi superconducting magnets with a conductor peak field of 6-7 T. A significant gain in performance can be achieved by replacing NbTi with Nb{sub 3}Sn, allowing solenoids and sextupole coils to reach a field of 15 T in the windings. In this paper we describe the design of a Nb{sub 3}Sn superconducting magnet for a fourth generation ECR source operating at a microwave frequency of 56 GHz. The magnet design features a configuration with an internal sextupole magnet surrounded by three solenoids. A finite element magnetic model has been used to investigate conductor peak fields and the operational margins. Results of the numerical analysis are presented and discussed.

  13. Relation between parameters of self-sustaining magnetically confined electron cloud and external conditions

    International Nuclear Information System (INIS)

    Yu Qingchang

    1991-01-01

    On the basis of the fluid theory of the axisymmetrical self-sustaining magnetically confined electron clouds an approximate analytical method is developed. By means of this method the relations between the parameters of this type of electron cloud and external conditions are studied. The parameters include electron density, electron temperature, drift angular frequency of electrons, radius of the electron cloud and electric potential at the centre of the electron cloud. They depend on the voltage, magnetic induction, pressure, electromagnetic field distribution in the confinement device and parameters of electron-atom collisions

  14. Magnetic field effects on electrical parameters of rf excited CO{sub 2} lasers

    Energy Technology Data Exchange (ETDEWEB)

    Tavassoli, S.H. [Laser Research Institute and Physics Department of Shahid Beheshti University, Evin, Tehran (Iran, Islamic Republic of)]. E-mail: h-tavassoli@cc.sbu.ac.ir; Latifi, H. [Laser Research Institute and Physics Department of Shahid Beheshti University, Evin, Tehran (Iran, Islamic Republic of)

    2005-02-14

    In the present Letter a rf excited CO{sub 2} laser embedded in an external, constant, and homogeneous magnetic field is considered. The magnetic field effects on some discharge parameters such as V-I characteristics, impedance of sheaths and positive column of plasma, intensity of visible emission from plasma and thickness of positive column are investigated. There is an increase in thickness of positive column and output power in presence of magnetic field. Magnetic field leads to an increase in the discharge voltage and impedance for lower current densities and a decrease for higher ones. There is a current density in which the magnetic field has no effects on discharge voltage and impedance. There are two peaks on intensity of visible emission from the discharge which at higher magnetic field are pushed out toward the electrodes.

  15. Parameters concerning the preparation and performance of a magnetic microparticle antibody

    International Nuclear Information System (INIS)

    Rongsen, Shen; Ruiyun, Xing; Fengqi, Zhou; Xiuzhen, Liu; Dingquan, Wang

    1997-01-01

    We have described 'Magnetic Microparticle Antibodies and Their Application to RIAs' in a recently published paper. In this article operative parameters for the preparation of a magnetic second antibody (MSA-II) including results of purification of donkey anti-rabbit (D X R) serum by an (NH 4 ) 2 SO 4 precipitation method, rates of recovery of products in preparation of magnetic nucleus (MN, Fe 3 O 4 microparticle), in distillation of acrolein (AL) and in preparation of polyacrolein magnetic particle (PAMP), change in pH value of suspension irradiated before and after 60 Co γ-irradiation and volume of wet sediment in separation of magnetic particles by a magnetic separator, etc., as well as correlation of levels of quality control (QC) sera obtained with liquid-phase double antibody assay (LDA) and MSA-II assay during four years were supplementarily summarized. These operative parameters would be helpful to mastering the procedures for preparation and/or use of the magnetic particles. The better correlation of levels of QC sera for both the assays showed the reliability of the magnetic antibody. (author)

  16. Repository environmental parameters and models/methodologies relevant to assessing the performance of high-level waste packages in basalt, tuff, and salt

    Energy Technology Data Exchange (ETDEWEB)

    Claiborne, H.C.; Croff, A.G.; Griess, J.C.; Smith, F.J.

    1987-09-01

    This document provides specifications for models/methodologies that could be employed in determining postclosure repository environmental parameters relevant to the performance of high-level waste packages for the Basalt Waste Isolation Project (BWIP) at Richland, Washington, the tuff at Yucca Mountain by the Nevada Test Site, and the bedded salt in Deaf Smith County, Texas. Guidance is provided on the identify of the relevant repository environmental parameters; the models/methodologies employed to determine the parameters, and the input data base for the models/methodologies. Supporting studies included are an analysis of potential waste package failure modes leading to identification of the relevant repository environmental parameters, an evaluation of the credible range of the repository environmental parameters, and a summary of the review of existing models/methodologies currently employed in determining repository environmental parameters relevant to waste package performance. 327 refs., 26 figs., 19 tabs.

  17. Repository environmental parameters and models/methodologies relevant to assessing the performance of high-level waste packages in basalt, tuff, and salt

    International Nuclear Information System (INIS)

    Claiborne, H.C.; Croff, A.G.; Griess, J.C.; Smith, F.J.

    1987-09-01

    This document provides specifications for models/methodologies that could be employed in determining postclosure repository environmental parameters relevant to the performance of high-level waste packages for the Basalt Waste Isolation Project (BWIP) at Richland, Washington, the tuff at Yucca Mountain by the Nevada Test Site, and the bedded salt in Deaf Smith County, Texas. Guidance is provided on the identify of the relevant repository environmental parameters; the models/methodologies employed to determine the parameters, and the input data base for the models/methodologies. Supporting studies included are an analysis of potential waste package failure modes leading to identification of the relevant repository environmental parameters, an evaluation of the credible range of the repository environmental parameters, and a summary of the review of existing models/methodologies currently employed in determining repository environmental parameters relevant to waste package performance. 327 refs., 26 figs., 19 tabs

  18. Assessment of Rock Magnetic Parameters for Fly Ash Pollution Screening in Topsoil of the Deccan Trap Basalt Area, India

    Science.gov (United States)

    Blaha, U.; Basavaiah, N.; Das, P. K.; Deenadayalan, K.

    2012-04-01

    Rock magnetic parameters of highly magnetic topsoil of the Deccan Trap basalt area are evaluated for their suitability for efficient environmental magnetic pollution screening. Parameters, such as magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (κ fd%), anhysteretic remanent magnetization (ARM), saturation isothermal remanent magnetization (SIRM), soft isothermal remanent magnetization (Soft IRM), as well as thermo-magnetic analysis (κ-T) are compared and assessed for best depiction of topsoil contamination due to ash deposition around the Nashik thermal power station (NTPS). Fifty-five topsoil samples, collected along north-south and west-east stretching transects of 24 km length, are the basis for evaluation of the specific ash distribution pattern around the plant and its adjacent ash pond. Similar decline of the magnetic signals with increasing distance from the point source is observed in the concentration dependent magnetic parameters and can be modeled. The magnetic grain size parameters instead reveal increasing trends with increasing distance. Verwey-transition and Hopkinson peak obtained from κ-T analyses demonstrate to be important parameters to prove fly ash accumulation in soils of basaltic origin. The importance of magnetic parameters for indirect tracing of pollutants, such as heavy metals, is shown by Pb, Zn and Cu data, revealing similar distribution pattern as obtained from the concentration dependent magnetic parameters. Confirmation of the presence of a very high amount of ash particles in the vicinity of the NTPS and a low number of particles in more distant areas is provided by scanning electron microscopy (SEM) on quantitatively extracted magnetic particles at 5.5 km and 11.9 km distance in eastern direction. The investigation demonstrates that the majority of the rock magnetic parameters has the potential to be successfully applied in environmental magnetic studies in areas with high magnetic background

  19. Manipulation of magnetic vortex parameters in disk-on-disk nanostructures with various geometry

    Directory of Open Access Journals (Sweden)

    Maxim E. Stebliy

    2015-03-01

    Full Text Available Magnetic nanostructures in the form of a sandwich consisting of two permalloy (Py disks with diameters of 600 and 200 nm separated by a nonmagnetic interlayer are studied. Magnetization reversal of the disk-on-disk nanostructures depends on the distance between centers of the small and big disks and on orientation of an external magnetic field applied during measurements. It is found that manipulation of the magnetic vortex chirality and the trajectory of the vortex core in the big disk is only possible in asymmetric nanostructures. Experimentally studied peculiarities of a motion path of the vortex core and vortex parameters by the magneto-optical Kerr effect (MOKE magnetometer are supported by the magnetic force microscopy imaging and micromagnetic simulations.

  20. Magnetic anisotropy and order parameter in nanostructured CoPt particles

    Science.gov (United States)

    Komogortsev, S. V.; Iskhakov, R. S.; Zimin, A. A.; Filatov, E. Yu.; Korenev, S. V.; Shubin, Yu. V.; Chizhik, N. A.; Yurkin, G. Yu.; Eremin, E. V.

    2013-10-01

    The correlation of magnetic anisotropy energy with order parameter in the crystallites of CoPt nanostructured particles prepared by thermal decomposition and further annealing has been studied by investigation of the approach magnetization to saturation curves and x-ray powder diffraction pattern profiles. It is shown that magnetic anisotropy energy value in partially ordered CoPt crystallite could be described as an intermediate case between two extremes, corresponding to either single or several c-domains of L10 phase in crystallite.

  1. Characterization of aging-induced microstructural changes in M250 maraging steel using magnetic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, K.V. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Vaidyanathan, S. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Kumar, Anish [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)]. E-mail: tjk@igcar.gov.in; Raj, Baldev [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Ray, K.K. [Indian Institute of Technology, Kharagpur 721302 (India)

    2007-05-15

    The best combinations of mechanical properties (yield stress and fracture toughness) of M250 maraging steel is obtained through short-term thermal aging (3-10 h) at 755 K. This is attributed to the microstructure containing precipitation of intermetallic phases in austenite-free low-carbon martensite matrix. Over-aged microstructure, containing reverted austenite degrades the mechanical properties drastically. Hence, it necessitates identification of a suitable non-destructive evaluation (NDE) technique for detecting any reverted austenite unambiguously during aging. The influence of aging on microstructure, room temperature hardness and non-destructive magnetic parameters such as coercivity (H {sub c}), saturation magnetization (M {sub s}) and magnetic Barkhausen emission (MBE) RMS peak voltage is studied in order to derive correlations between these parameters in aged M250 maraging steel. Hardness was found to increase with precipitation of intermetallics during initial aging and decrease at longer durations due to austenite reversion. Among the different magnetic parameters studied, MBE RMS peak voltage was found to be very sensitive to austenite reversion (non-magnetic phase) as they decreased drastically up on initiation of austenite reversion. Hence, this parameter can be effectively utilized to detect and quantify the reverted austenite in maraging steel specimen. The present study clearly indicates that the combination of MBE RMS peak voltage and hardness can be used for unambiguous characterization of microstructural features of technological and practical importance (3-10 h of aging duration at 755 K) in M250 grade maraging steel.

  2. Characterization of aging-induced microstructural changes in M250 maraging steel using magnetic parameters

    International Nuclear Information System (INIS)

    Rajkumar, K.V.; Vaidyanathan, S.; Kumar, Anish; Jayakumar, T.; Raj, Baldev; Ray, K.K.

    2007-01-01

    The best combinations of mechanical properties (yield stress and fracture toughness) of M250 maraging steel is obtained through short-term thermal aging (3-10 h) at 755 K. This is attributed to the microstructure containing precipitation of intermetallic phases in austenite-free low-carbon martensite matrix. Over-aged microstructure, containing reverted austenite degrades the mechanical properties drastically. Hence, it necessitates identification of a suitable non-destructive evaluation (NDE) technique for detecting any reverted austenite unambiguously during aging. The influence of aging on microstructure, room temperature hardness and non-destructive magnetic parameters such as coercivity (H c ), saturation magnetization (M s ) and magnetic Barkhausen emission (MBE) RMS peak voltage is studied in order to derive correlations between these parameters in aged M250 maraging steel. Hardness was found to increase with precipitation of intermetallics during initial aging and decrease at longer durations due to austenite reversion. Among the different magnetic parameters studied, MBE RMS peak voltage was found to be very sensitive to austenite reversion (non-magnetic phase) as they decreased drastically up on initiation of austenite reversion. Hence, this parameter can be effectively utilized to detect and quantify the reverted austenite in maraging steel specimen. The present study clearly indicates that the combination of MBE RMS peak voltage and hardness can be used for unambiguous characterization of microstructural features of technological and practical importance (3-10 h of aging duration at 755 K) in M250 grade maraging steel

  3. Characterization of aging-induced microstructural changes in M250 maraging steel using magnetic parameters

    Science.gov (United States)

    Rajkumar, K. V.; Vaidyanathan, S.; Kumar, Anish; Jayakumar, T.; Raj, Baldev; Ray, K. K.

    2007-05-01

    The best combinations of mechanical properties (yield stress and fracture toughness) of M250 maraging steel is obtained through short-term thermal aging (3-10 h) at 755 K. This is attributed to the microstructure containing precipitation of intermetallic phases in austenite-free low-carbon martensite matrix. Over-aged microstructure, containing reverted austenite degrades the mechanical properties drastically. Hence, it necessitates identification of a suitable non-destructive evaluation (NDE) technique for detecting any reverted austenite unambiguously during aging. The influence of aging on microstructure, room temperature hardness and non-destructive magnetic parameters such as coercivity ( Hc), saturation magnetization ( Ms) and magnetic Barkhausen emission (MBE) RMS peak voltage is studied in order to derive correlations between these parameters in aged M250 maraging steel. Hardness was found to increase with precipitation of intermetallics during initial aging and decrease at longer durations due to austenite reversion. Among the different magnetic parameters studied, MBE RMS peak voltage was found to be very sensitive to austenite reversion (non-magnetic phase) as they decreased drastically up on initiation of austenite reversion. Hence, this parameter can be effectively utilized to detect and quantify the reverted austenite in maraging steel specimen. The present study clearly indicates that the combination of MBE RMS peak voltage and hardness can be used for unambiguous characterization of microstructural features of technological and practical importance (3-10 h of aging duration at 755 K) in M250 grade maraging steel.

  4. The magnetically driven imploding liner parameter space of the ATLAS capacitor bank

    CERN Document Server

    Lindemuth, I R; Faehl, R J; Reinovsky, R E

    2001-01-01

    Summary form only given, as follows. The Atlas capacitor bank (23 MJ, 30 MA) is now operational at Los Alamos. Atlas was designed primarily to magnetically drive imploding liners for use as impactors in shock and hydrodynamic experiments. We have conducted a computational "mapping" of the high-performance imploding liner parameter space accessible to Atlas. The effect of charge voltage, transmission inductance, liner thickness, liner initial radius, and liner length has been investigated. One conclusion is that Atlas is ideally suited to be a liner driver for liner-on-plasma experiments in a magnetized target fusion (MTF) context . The parameter space of possible Atlas reconfigurations has also been investigated.

  5. Dietary supplementation of tiger nut alters biochemical parameters relevant to erectile function in l-NAME treated rats.

    Science.gov (United States)

    Olabiyi, Ayodeji A; Carvalho, Fabiano B; Bottari, Nathieli B; Lopes, Thauan F; da Costa, Pauline; Stefanelo, Naiara; Morsch, Vera M; Akindahunsi, Afolabi A; Oboh, Ganiyu; Schetinger, Maria Rosa

    2018-07-01

    Tiger nut tubers have been reportedly used for the treatment of erectile dysfunction (ED) in folk medicine without scientific basis. Hence, this study evaluated the effect of tiger nut on erectile dysfunction by assessing biochemical parameters relevant to ED in male rats by nitric oxide synthase (NOS) inhibitor, Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME) treatment. Rats were divided into five groups (n = 10) each: Control group; l-NAME plus basal diet; l-NAME plus Sildenafil citrate; diet supplemented processed tiger nut (20%) plus l-NAME;diet supplemented raw tiger nut (20%) plus l-NAME. l-NAME pre-treatment (40 mg/kg/day) lasted for 14 days. Arginase, acetycholinesterase (AChE) and adenosine deaminase (ADA) activities as well as nitric oxide levels (NO) in serum, brain and penile tissue were measured. l-NAME increased the activity of arginase, AChE and ADA and reduced NO levels. However, dietary supplementation with tiger nut caused a reduction on the activities of the above enzymes and up regulated nitric oxide levels when compared to the control group. The effect of tiger nut supplemented diet may be said to prevent alterations of the activities of the enzymes relevant in erectile function. Quercetin was revealed to be the most active component of tiger nut tuber by HPLC finger printing. Copyright © 2018. Published by Elsevier Ltd.

  6. Exploratory studies of flowing liquid metal divertor options for fusion-relevant magnetic fields in the MTOR facility

    International Nuclear Information System (INIS)

    Ying, A.Y.; Abdou, M.A.; Morley, N.; Sketchley, T.; Woolley, R.; Burris, J.; Kaita, R.; Fogarty, P.; Huang, H.; Lao, X.; Narula, M.; Smolentsev, S.; Ulrickson, M.

    2004-01-01

    This paper reports on experimental findings on liquid metal (LM) free surface flows crossing complex magnetic fields. The experiments involve jet and film flows using GaInSn and are conducted at the UCLA MTOR facility. The goal of this study is to understand the magnetohydrodynamics (MHD) features associated with such a free surface flow in a fusion-relevant magnetic field environment, and determine what LM free surface flow option is most suitable for lithium divertor particle pumping and surface heat removal applications in a near-term experimental plasma device, such as NSTX. Experimental findings indicate that a steady transverse magnetic field, even with gradients typical of NSTX outer divertor conditions, stabilizes a LM jet flow--reducing turbulent disturbances and delaying jet breakup. Important insights into the MHD behavior of liquid metal films under NSTX-like environments are also presented. It is possible to establish an uphill liquid metal film flow on a conducting substrate, although the MHD drag experienced by the flow could be strong and cause the flow to pile-up under simulated NSTX magnetic field conditions. The magnetic field changes the turbulent film flow so that wave structures range from 2D column-type surface disturbances at regions of high magnetic field, to ordinary hydrodynamic turbulence wave structures at regions of low field strength at the outboard. Plans for future work are also presented

  7. Relevance of sub-surface chip layers for the lifetime of magnetically trapped atoms

    DEFF Research Database (Denmark)

    Zhang, H. B.; Henkel, C; Haller, E.

    2005-01-01

    on the thickness of that layer, as long as the layers below have a much smaller conductivity; essentially the same magnetic noise would be obtained with a metallic membrane suspended in vacuum. Based on our theory we give general scaling laws of how to reduce the effect of surface magnetic noise on the trapped...... measurements where the center of a side guide trap is laterally shifted with respect to the current carrying wire using additional bias fields. Comparing the experiment to theory, we find a fair agreement and demonstrate that for a chip whose topmost layer is metallic, the magnetic noise depends essentially...

  8. The Influence of the Axial Magnetic Field Upon-the Coaxial Plasma Gun Parameters

    International Nuclear Information System (INIS)

    El-Aragi, G.M.; EL-Demrdash, A.

    2001-01-01

    This study concerns with the influence of an applied axial magnetic field upon the electrical parameters of a coaxial plasma gun device. The experimental results are investigated with 0.5 KJ plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied

  9. Correlation of Magnetic Fields with Solar Wind Plasma Parameters at 1AU

    Science.gov (United States)

    Shen, F.

    2017-12-01

    The physical parameters of the solar wind observed in-situ near 1AU have been studied for several decades, and relationships between them, such as the positive correlation between the solar wind plasma temperature T and velocity V, and the negative correlation between density N and velocity V, are well known. However, the magnetic field intensity does not appear to be well correlated with any individual plasma parameter. In this paper, we discuss previously under-reported correlations between B and the combined plasma parameters √NV2 as well as between B and √NT. These two correlations are strong during the periods of corotating interaction regions and high speed streams, moderate during intervals of slow solar wind, and rather poor during the passage of interplanetary coronal mass ejections. The results indicate that the magnetic pressure in the solar wind is well correlated both with the plasma dynamic pressure and the thermal pressure. Then, we employ a 3D MHD model to simulate the formation of the relationships between the magnetic strength B and √NV2 as well as √NT observed at 1AU. The inner boundary condition is derived by empirical models, with the magnetic field and density are optional. Five kinds of boundary conditions at the inner boundary of heliosphere are tested. In the cases that the magnetic field is related to speed at the inner boundary, the correlation coefficients between B and √NV2 as well as between B and √NT are even higher than that in the observational results. At 1AU the simulated radial magnetic field shows little latitude dependence, which matches the observation of Ulysses. Most of the modeled characters in these cases are closer to observation than others. This inner boundary condition may more accurately characterize Sun's magnetic influence on the heliosphere. The new input may be able to improve the simulation of CME propagation in the inner heliosphere and the space weather forecasting.

  10. Surgeon Reported Outcome Measure for Spine Trauma an International Expert Survey Identifying Parameters Relevant for The Outcome of Subaxial Cervical Spine Injuries

    NARCIS (Netherlands)

    Sadiqi, Said; Verlaan, Jorrit Jan; Lehr, A. M.; Dvorak, Marcel F.; Kandziora, Frank; Rajasekaran, S.; Schnake, Klaus J.; Vaccaro, Alexander R.; Oner, F. C.

    2016-01-01

    STUDY DESIGN.: International web-based survey OBJECTIVE.: To identify clinical and radiological parameters that spine surgeons consider most relevant when evaluating clinical and functional outcomes of subaxial cervical spine trauma patients. SUMMARY OF BACKGROUND DATA.: While an outcome instrument

  11. The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

    Science.gov (United States)

    Xiao, Ling; Sun, Y. H.; Yu, Lie

    2011-07-01

    This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

  12. The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

    International Nuclear Information System (INIS)

    Xiao Ling; Yu Lie; Sun, Y H

    2011-01-01

    This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

  13. Comparing UV/EUV line parameters and magnetic field in a quiescent prominence with tornadoes

    Science.gov (United States)

    Levens, P. J.; Labrosse, N.; Schmieder, B.; López Ariste, A.; Fletcher, L.

    2017-10-01

    Context. Understanding the relationship between plasma and the magnetic field is important for describing and explaining the observed dynamics of solar prominences. Aims: We determine if a close relationship can be found between plasma and magnetic field parameters, measured at high resolution in a well-observed prominence. Methods: A prominence observed on 15 July 2014 by the Interface Region Imaging Spectrograph (IRIS), Hinode, the Solar Dynamics Observatory (SDO), and the Télescope Héliographique pour l'Étude du Magnétisme et des Instabilités Solaires (THEMIS) is selected. We perform a robust co-alignment of data sets using a 2D cross-correlation technique. Magnetic field parameters are derived from spectropolarimetric measurements of the He I D3 line from THEMIS. Line ratios and line-of-sight velocities from the Mg II h and k lines observed by IRIS are compared with magnetic field strength, inclination, and azimuth. Electron densities are calculated using Fe xii line ratios from the Hinode Extreme-ultraviolet Imaging Spectrometer, which are compared to THEMIS and IRIS data. Results: We find Mg II k/h ratios of around 1.4 everywhere, similar to values found previously in prominences. Also, the magnetic field is strongest ( 30 G) and predominantly horizontal in the tornado-like legs of the prominence. The k3 Doppler shift is found to be between ±10 km s-1 everywhere. Electron densities at a temperature of 1.5 × 106 K are found to be around 109 cm-3. No significant correlations are found between the magnetic field parameters and any of the other plasma parameters inferred from spectroscopy, which may be explained by the large differences in the temperatures of the lines used in this study. Conclusions: This is the first time that a detailed statistical study of plasma and magnetic field parameters has been performed at high spatial resolution in a prominence. Our results provide important constraints on future models of the plasma and magnetic field in

  14. Ring current and auroral electrojets in connection with interplanetary medium parameters during magnetic storm

    Directory of Open Access Journals (Sweden)

    Y. I. Feldstein

    1994-06-01

    Full Text Available The relationship between the auroral electrojet indices (AE and the ring current magnetic field (DR was investigated by observations obtained during the magnetic storm on 1-3 April 1973. During the storm main phase the DR development is accompanied by a shift of the auroral electrojets toward the equator. As a result, the standard AE indices calculated on the basis of data from auroral observatories was substantially lower than the real values (AE'. To determine AE' during the course of a storm main phase data from subauroral magnetic observatories should be used. It is shown that the intensity of the indices (AE' which take into account the shift of the electrojets is increased substantially relative to the standard indices during the storm main phase. AE' values are closely correlated with geoeffective solar wind parameters. A high correlation was obtained between AE' and the energy flux into the ring current during the storm main phase. Analysis of magnetic field variations during intervals with intense southward IMF components demonstrates a decrease of the saturation effect of auroral electrojet currents if subauroral stations magnetic field variations are taken into account. This applies both to case studies and statistical data. The dynamics of the electrojets in connection with the development of the ring current and of magnetospheric substorms can be described by the presence (absence of saturation for minimum (maximum AE index values during a 1-h interval. The ring current magnetic field asymmetry (ASY was calculated as the difference between the maximum and minimum field values along a parallel of latitude at low latitudes. The ASY value is closely correlated with geoeffective solar wind parameters and simultaneously is a more sensitive indicator of IMF Bz variations than the symmetric ring current. ASY increases (decreases faster during the main phase (the recovery phase than DR. The magnetic field decay at low latitudes in the

  15. A New Identification Method of Both Magnetization Characteristic and Parameters of an Unloaded Transformer

    Directory of Open Access Journals (Sweden)

    Petr Orsag

    2008-01-01

    Full Text Available In this paper a new method of identification of both the magnetization characteristic and the instantaneous parameters G(t and K(t of a single-phase transformer under a sinusoidal supply voltage is proposed. The instantaneous conductance G(t and inverse inductance K(t of the transformer cross section are determined by the scalar product of time functions. The magnetization characteristic is derived by means of the inverse inductance K(t. The method is practically applied to an isolating transformer.

  16. Improving the GIS-DRP Approach by Means of DelineatingRunoff Characteristics with New Discharge Relevant Parameters

    Directory of Open Access Journals (Sweden)

    Marco Hümann

    2013-01-01

    Full Text Available At present it is common to use geographic information system (GIS applications to assess runoff generation. One of these GIS-based tools to generate maps of dominant runoff processes is the so called GIS-DRP approach. The tool, which has been developed mainly based on agricultural areas, uses commonly available input data like a digital elevation model (DEM, geological information as well as land use information. The aim of this study is to test, validate and improve this GIS-DRP method for forested and silviculture areas. Hence, soil-hydrologic investigations and several mapping techniques of dominant runoff processes were conducted on 25 test-plots in four forested catchments in Rhineland-Palatinate (Germany and the Grand Duchy of Luxembourg. By comparing the results of the mapping techniques and those of the test plots, weak points in the original GIS-DRP method were detected. Subsequently, it was possible to enhance the GIS-DRP approach by incorporating new discharge relevant parameters like topsoil sealing, extreme weather events and semipermeability of the substratum. Moreover, the improved GIS-DRP approach can be widely used in different landscapes and for different fields of application. The adapted method can now support foresters and decision makers in forestry planning, answer questions concerning the landscape water balance and peripheral water retention or provide extra information for sustainable forest planning in times of a changing climate.

  17. Test of piezo-ceramic motor technology in ITER relevant high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Monti, Chiara, E-mail: chiara.monti@enea.it [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Besi Vetrella, Ugo; Mugnaini, Giampiero; Neri, Carlo; Rossi, Paolo; Viola, Rosario [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Dubus, Gregory; Damiani, Carlo [Fusion for Energy, c/ Josep Pla, 2 Torres Diagonal Litoral, 08019 Barcelona (Spain)

    2014-10-15

    In the framework of a Fusion for Energy (F4E) grant, a test campaign started in 2012 in order to assess the performance of the in-vessel viewing system (IVVS) probe concept and to verify its compatibility when exposed to ITER typical working conditions. ENEA laboratories went through with several tests simulating high magnetic fields, high temperature, high vacuum, gamma radiation and neutron radiation. A customized motor has been adopted to study the performances of ultrasonic piezo motors technology in high magnetic field conditions. This paper reports on the testing activity performed on the motor in a multi Tesla magnetic field. The job was carried out in a test facility of ENEA laboratories able to achieve 14 T. A maximum field of 10 T, fully compliant with ITER requirements (8 T), was applied. A specific mechanical assembly has been designed and manufactured to hold the motor in the region with high homogeneity of the field. Results obtained so far indicate that the motor is compatible with high magnetic fields, and are presented in the paper.

  18. New parameters in adaptive testing of ferromagnetic materials utilizing magnetic Barkhausen noise

    International Nuclear Information System (INIS)

    Pal’a, Jozef; Ušák, Elemír

    2016-01-01

    A new method of magnetic Barkhausen noise (MBN) measurement and optimization of the measured data processing with respect to non-destructive evaluation of ferromagnetic materials was tested. Using this method we tried to found, if it is possible to enhance sensitivity and stability of measurement results by replacing the traditional MBN parameter (root mean square) with some new parameter. In the tested method, a complex set of the MBN from minor hysteresis loops is measured. Afterward, the MBN data are collected into suitably designed matrices and optimal parameters of MBN with respect to maximum sensitivity to the evaluated variable are searched. The method was verified on plastically deformed steel samples. It was shown that the proposed measuring method and measured data processing bring an improvement of the sensitivity to the evaluated variable when comparing with measuring traditional MBN parameter. Moreover, we found a parameter of MBN, which is highly resistant to the changes of applied field amplitude and at the same time it is noticeably more sensitive to the evaluated variable. - Highlights: • We test an adaptive magnetic Barkhausen noise method. • The method utilizes measuring a complex set of Barkhausen noise signals. • We define new matrices of parameters for this method. • The pulse density is highly resistant to changes in applied field amplitude.

  19. Evaluation of brake parameters in copper discs of various thicknesses and speeds using Neodymium – Iron – Boron Magnets

    Directory of Open Access Journals (Sweden)

    Anantha Krishna G. L.

    2018-01-01

    Full Text Available Neodymium – Iron – Boron (NdFeB permanent magnets of 12.5 mm thickness and 50 mm diameter are chosen for analyses because of their higher remanence and coercivity. Experimental analyses were carried out with Copper discs of thickness 4 mm, 6 mm and 8 mm at 2000 rpm, 3000 rpm, 4000 rpm and 5000 rpm. Experiments were conducted with three different positions of magnets such as 2 coaxial magnets, single magnet and single magnet with sudden application conditions. The brake parameters recorded are % speed reduction, deceleration and time taken. In 2 coaxial magnets condition, brake parameters are better in 6 mm thick disc. In single magnet condition, the brake parameters in 6 mm thick disc are found to be more consistent than 4 mm and 8 mm thick discs. In single magnet with sudden application condition, in 4 mm thick disc, the brake parameters are found better. During analysis, very high repulsion was experienced by magnet with 8 mm thick Copper disc at all the above mentioned speeds in single magnet with sudden application condition. For high speed train applications, single magnet condition with 6mm thick disc may be suitable. For high speed automotive applications, single magnet with sudden application condition with 4 mm thick disc may be suitable.

  20. Clinical relevance of magnetic resonance imaging and magnetic resonance spectroscopy for the cirrhotic without overt hepatic encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Fujishima, Yukou; Kato, Akinobu; Suzuki, Kazuyuki [Iwate Medical Univ., Morioka (Japan). School of Medicine

    1999-04-01

    To clarify the changes of pallidal high intensity on T1-weighted magnetic resonance imaging (MRI) and brain metabolites on magnetic resonance spectroscopy (MRS) as related to the severity of hepatic functions, the concentrations of blood ammonia (B-NH{sub 3}) and the levels of trace elements (Mn, Cu and Zn), 30 patients with liver cirrhosis without hepatic encephalopathy (HE) and 5 age-matched healthy control subjects underwent MRI and proton MRS. Pallidal high intensity (Pl index) and glutamine are higher in cirrhosis, and myo-inositol is lower than that of control statistically. In cirrhosis, there were statistically negative correlation between B-NH{sub 3} and myo-inositol and positive correlation between B-NH{sub 3} and glutamine. There was a statistically lower myo-inositol and higher Pl index, glutamine as the severity of hepatic functions increased. Furthermore there was a statistically positive correlation between Pl index and Mn. These data suggest that the changes of MRI and MRS findings already detected in cirrhosis without HE and these abnormalities may be reflect the B-NH{sub 3} and Mn metabolism and the severity of the hepatic functions. (author)

  1. Clinical relevance of magnetic resonance imaging and magnetic resonance spectroscopy for the cirrhotic without overt hepatic encephalopathy

    International Nuclear Information System (INIS)

    Fujishima, Yukou; Kato, Akinobu; Suzuki, Kazuyuki

    1999-01-01

    To clarify the changes of pallidal high intensity on T1-weighted magnetic resonance imaging (MRI) and brain metabolites on magnetic resonance spectroscopy (MRS) as related to the severity of hepatic functions, the concentrations of blood ammonia (B-NH 3 ) and the levels of trace elements (Mn, Cu and Zn), 30 patients with liver cirrhosis without hepatic encephalopathy (HE) and 5 age-matched healthy control subjects underwent MRI and proton MRS. Pallidal high intensity (Pl index) and glutamine are higher in cirrhosis, and myo-inositol is lower than that of control statistically. In cirrhosis, there were statistically negative correlation between B-NH 3 and myo-inositol and positive correlation between B-NH 3 and glutamine. There was a statistically lower myo-inositol and higher Pl index, glutamine as the severity of hepatic functions increased. Furthermore there was a statistically positive correlation between Pl index and Mn. These data suggest that the changes of MRI and MRS findings already detected in cirrhosis without HE and these abnormalities may be reflect the B-NH 3 and Mn metabolism and the severity of the hepatic functions. (author)

  2. Magnetic Parameter Changes in Soil and Sediments in the Presence of Hydrocarbon Contamination

    Science.gov (United States)

    Appel, E.; Porsch, K.; Rijal, M. L.; Ameen, N. N.; Kappler, A.

    2014-12-01

    Magnetic proxies were successfully used for fast and non-destructive detection of fly ash related heavy metal pollution. Correlations of magnetic signals with organic contaminants in soils and sediments were also reported; however, their significance is unclear because of co-existing heavy metal pollution. At a hydrocarbon (HC) contaminated former military airbase (Hradcany, Czech Rep.), where heavy metal contents are insignificant, we detected clearly higher magnetic concentrations at the top of the groundwater fluctuation (GWF) zone. Frequent GWF by up to ca. one meter was caused through remediation by air sparging. In this study and all previous ones magnetite was identified as the dominant phase for higher magnetic concentrations. To determine the importance of microbial activity and soil parameters on changes in magnetic susceptibility (MS) laboratory batch experiments with different microbially active and sterile soils without carbon addition and with gasoline amendment were setup. MS of these microcosms was followed weekly. Depending on the soil MS either increased or decreased by up to ~7% and remained constant afterwards. The main findings were that MS changes were mainly microbially driven and influenced by the bioavailable Fe content, the initial MS and the organic carbon content of the soils. Moreover, we tested magnetic changes in laboratory columns, filled with sand from the field site Hradcany, by simulating water level changes. The observed changes were small and hardly statistically significant. Our laboratory studies revealed that different factors influence changes in magnetic properties of soil/sediments after HC contamination, with much smaller effects than expected from anomalies observed at field sites. With the present results, the ambitious goal of using magnetic monitoring for detecting HC contaminations by oil spills seem far from practical application.

  3. Exploring liquid metal plasma facing component (PFC) concepts-Liquid metal film flow behavior under fusion relevant magnetic fields

    International Nuclear Information System (INIS)

    Narula, M.; Abdou, M.A.; Ying, A.; Morley, N.B.; Ni, M.; Miraghaie, R.; Burris, J.

    2006-01-01

    The use of fast moving liquid metal streams or 'liquid walls' as a plasma contact surface is a very attractive option and has been looked upon with considerable interest over the past several years, both by the plasma physics and fusion engineering programs. Flowing liquid walls provide an ever replenishing contact surface to the plasma, leading to very effective particle pumping and surface heat flux removal. A key feasibility issue for flowing liquid metal plasma facing component (PFC) systems, pertains to their magnetohydrodynamic (MHD) behavior under the spatially varying magnetic field environment, typical of a fusion device. MHD forces hinder the development of a smooth and controllable liquid metal flow needed for PFC applications. The present study builds up on the ongoing research effort at UCLA, directed towards providing qualitative and quantitative data on liquid metal free surface flow behavior under fusion relevant magnetic fields

  4. Definitive determination of the transverse Hamiltonian parameters in the single molecule magnet Mn_12-Ac

    Science.gov (United States)

    Edwards, Rachel S.; Hill, Stephen; North, J. Micah; Dalal, Naresh; Jones, Shaela; Maccagnano, Sara

    2003-03-01

    We present high frequency high field electron paramagnetic resonance (EPR) measurements on the single molecule magnet Mn_12-Ac. Using a split coil magnet and highly sensitive resonant cavity techniques we are able to perform an angle dependent study of the single crystal EPR with the field applied in the hard plane, and hence unambiguously determine the transverse Hamiltonian parameters to fourth order. A variation in the line-shape of the resonances with angle supports the recent proposal of a ligand disorder in this material causing local quadratic anisotropy, and is used to determine the magnitude of the second order transverse term. This could have important implications for describing magnetic quantum tunneling in Mn_12-Ac. S. Hill, J.A.A.J. Perenboom, N.S. Dalal, T. Hathaway, T. Stalcup and J.S. Brooks, Phys. Rev. Lett. 80, 2453 (1998). A. Cornia, R. Sessoli, L. Sorace, D. Gatteschi, A.L. Barra and C. Daiguebonne, cond-mat/0112112.

  5. Mapping magnetized geologic structures from space: The effect of orbital and body parameters

    Science.gov (United States)

    Schnetzler, C. C.; Taylor, P. T.; Langel, R. A.

    1984-01-01

    When comparing previous satellite magnetometer missions (such as MAGSAT) with proposed new programs (for example, Geopotential Research Mission, GRM) it is important to quantify the difference in scientific information obtained. The ability to resolve separate magnetic blocks (simulating geological units) is used as a parameter for evaluating the expected geologic information from each mission. The effect of satellite orbital altitude on the ability to resolve two magnetic blocks with varying separations is evaluated and quantified. A systematic, nonlinear, relationship exists between resolution and distance between magnetic blocks as a function of orbital altitude. The proposed GRM would provide an order-of-magnitude greater anomaly resolution than the earlier MAGSAT mission for widely separated bodies. The resolution achieved at any particular altitude varies depending on the location of the bodies and orientation.

  6. Variation of Magnetic Field (By , Bz Polarity and Statistical Analysis of Solar Wind Parameters during the Magnetic Storm Period

    Directory of Open Access Journals (Sweden)

    Ga-Hee Moon

    2011-06-01

    Full Text Available It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME-driven storms, co-rotating interaction region (CIR-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF By and Bz components (in geocentric solar magnetospheric coordinate system coordinate during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of Bz < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF Bz (T1~T4 is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0% under the Bz < 0 condition. It is found that the correlation is highest between the time-integrated IMF Bz and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is

  7. Parameters and definitions in applied technique quality test for nuclear magnetic resonance imaging system (NMRI)

    International Nuclear Information System (INIS)

    Lin Zhikai; Zhao Lancai

    1999-08-01

    During the past two decades, medical diagnostic imaging technique has achieved dramatic development such as CT, MRI, PET, DSA and so on. The most striking examples of them are the application of X ray computerized tomography (CT) and magnetic resonance imaging in the field of medical diagnosis. It can be predicted that magnetic resonance imaging (MRI) will definitely have more widespread prospects of applications and play more and more important role in clinical diagnosis looking forward to the development of image diagnostic technique for 21 st century. The authors also present the measuring methods for some parameters. The parameters described can be used for reference by clinical diagnosticians, operators on MRI and medical physicists who engages in image quality assurance (QA) and control (QC) in performing MRI acceptance test and routine test

  8. Investigation of shock compressed plasma parameters by interaction with magnetic field

    International Nuclear Information System (INIS)

    Dudin, S. V.; Fortov, V. E.; Gryaznov, V. K.; Mintsev, V. B.; Shilkin, N. S.; Ushnurtsev, A. E.

    1998-01-01

    The Hall effect parameters in shock compressed air, helium and xenon have been estimated and results of experiments with air and helium plasma are presented. Explosively driven shock tubes were used for the generation of strong shock waves. To obtain magnetic field a solenoid was winded over the shock tube. Calculations of dense shock compressed plasma parameters were carried out to plan the experiments. In the experiments with the magnetic field of ∼5 T it was found, that air plasma slug was significantly heated by the whirlwind electrical field. The reflected shock waves technique was used in the experiments with helium. Results on measurements of electrical conductivity and electron concentration of helium are presented

  9. Gaussian optics calculations of the parameters of a magnetic sector energy analyzer

    International Nuclear Information System (INIS)

    Zaluzec, N.J.

    1978-01-01

    The design of a magnetic deflection system for use as an electron energy loss spectrometer can be a complex process if one takes the most general approach. However, for application to materials research the design process can be reduced to three basic steps. First, the qualitative features of the overall system are defined--i.e., incident electron energy, required resolution, type of magnet, the desired focal properties, etc. Secondly, the design parameters necessary to meet these requirements are calculated using the appropriate equations. Finally, once the magnetic field has been specified, ray-tracing techniques can be employed to verify the system response to the conditions defined in the first two steps. The calculation of the parameters of a uniform field magnetic sector analyzer capable of energy resolutions of 20 ppM or better are considered. Higher resolution is attainable; however, for most materials work, more important considerations are the attainment of double focusing to improve S/N, the minimization of aberrations and the achievement of a flat image plane to facilitate parallel data recording

  10. Soft magnetic properties and damping parameter of (FeCo-Al alloy thin films

    Directory of Open Access Journals (Sweden)

    Isao Kanada

    2017-05-01

    Full Text Available For high frequency device applications, a systematic study of the soft magnetic properties and magnetization dynamics of (FeCo-Al alloy thin films has been carried out. A low effective damping parameter αeff of 0.002 and a high saturation magnetization of about 1,800 emu/cc are obtained at y=0.2∼0.3 for (Fe1-yCoy98Al2 alloy thin films deposited onto fused silica and MgO(100 at an ambient temperature during deposition. Those films are of the bcc structure with the orientation normal to the film plane. They possess a columnar structure, grown along the film normal. The column width is found to be about 20 nm for y=0.25. It is concluded that the (FeCo-Al thin films with a damping parameter as low as 0.002 and high saturation magnetization of about 1,800 emu/cc have been successfully fabricated, and that they are potential for future high frequency device applications.

  11. Uncertainty Reduction Via Parameter Design of A Fast Digital Integrator for Magnetic Field Measurement

    CERN Document Server

    Arpaia, P; Lucariello, G; Spiezia, G

    2007-01-01

    At European Centre of Nuclear Research (CERN), within the new Large Hadron Collider (LHC) project, measurements of magnetic flux with uncertainty of 10 ppm at a few of decades of Hz for several minutes are required. With this aim, a new Fast Digital Integrator (FDI) has been developed in cooperation with University of Sannio, Italy [1]. This paper deals with the final design tuning for achieving target uncertainty by means of experimental statistical parameter design.

  12. The effect of magnetic storm on the bottomside profile parameters B0 and

    International Nuclear Information System (INIS)

    Adeniyi, J.O.; Radicella, S.M.

    2001-01-01

    We have used data from an equatorial station for the investigation of magnetic storm effects on B0 and B1. Three storm events, which occurred in January, April and October of a low solar activity year (1995), were used for the study. B0 is the parameter that is mostly affected and the effect is concentrated on the daytime period (0700-1700LT). (author)

  13. Experimental evaluation of stable long term operation of semiconductor magnetic sensors at ITER relevant environment

    Czech Academy of Sciences Publication Activity Database

    Bolshakova, I.; Belyaev, S.; Bulavin, M.; Brudnyi, V.; Chekanov, V.; Coccorese, V.; Ďuran, Ivan; Gerasimov, S.; Holyaka, R.; Kargin, N.; Konopleva, R.; Kost, Ya.; Kuech, T.; Kulikov, S.; Makido, O.; Moreau, Ph.; Murari, A.; Quercia, A.; Shurygin, F.; Strikhanov, M.; Timoshyn, S.; Vasil’evskii, I.; Vinichenko, A.

    2015-01-01

    Roč. 55, č. 8 (2015), 083006-083006 ISSN 0029-5515 R&D Projects: GA ČR GAP205/10/2055 EU Projects: European Commission(XE) 633053 Institutional support: RVO:61389021 Keywords : Hall sensors * 3D probes * steady state * magnetic measurement instrumentation * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015 http://iopscience.iop.org/article/10.1088/0029-5515/55/8/083006/meta;jsessionid=534DB19F0353E8F68E6E558F2A324088.c2.iopscience.cld.iop.org

  14. Evaluating the influence of initial magnetization conditions on extracted exchange parameters in NMR relaxation experiments: applications to CPMG and CEST

    Energy Technology Data Exchange (ETDEWEB)

    Yuwen, Tairan; Sekhar, Ashok; Kay, Lewis E., E-mail: kay@pound.med.utoronto.ca [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada)

    2016-08-15

    Transient excursions of native protein states to functionally relevant higher energy conformations often occur on the μs–ms timescale. NMR spectroscopy has emerged as an important tool to probe such processes using techniques such as Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion and Chemical Exchange Saturation Transfer (CEST). The extraction of kinetic and structural parameters from these measurements is predicated upon mathematical modeling of the resulting relaxation profiles, which in turn relies on knowledge of the initial magnetization conditions at the start of the CPMG/CEST relaxation elements in these experiments. Most fitting programs simply assume initial magnetization conditions that are given by equilibrium populations, which may be incorrect in certain implementations of experiments. In this study we have quantified the systematic errors in extracted parameters that are generated from analyses of CPMG and CEST experiments using incorrect initial boundary conditions. We find that the errors in exchange rates (k{sub ex}) and populations (p{sub E}) are typically small (<10 %) and thus can be safely ignored in most cases. However, errors become larger and cannot be fully neglected (20–40 %) as k{sub ex} falls near the lower limit of each method or when short CPMG/CEST relaxation elements are used in these experiments. The source of the errors can be rationalized and their magnitude given by a simple functional form. Despite the fact that errors tend to be small, it is recommended that the correct boundary conditions be implemented in fitting programs so as to obtain as robust estimates of exchange parameters as possible.

  15. Optimization of Saturn paraboloid magnetospheric field model parameters using Cassini equatorial magnetic field data

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2016-07-01

    Full Text Available The paraboloid model of Saturn's magnetosphere describes the magnetic field as being due to the sum of contributions from the internal field of the planet, the ring current, and the tail current, all contained by surface currents inside a magnetopause boundary which is taken to be a paraboloid of revolution about the planet-Sun line. The parameters of the model have previously been determined by comparison with data from a few passes through Saturn's magnetosphere in compressed and expanded states, depending on the prevailing dynamic pressure of the solar wind. Here we significantly expand such comparisons through examination of Cassini magnetic field data from 18 near-equatorial passes that span wide ranges of local time, focusing on modelling the co-latitudinal field component that defines the magnetic flux passing through the equatorial plane. For 12 of these passes, spanning pre-dawn, via noon, to post-midnight, the spacecraft crossed the magnetopause during the pass, thus allowing an estimate of the concurrent subsolar radial distance of the magnetopause R1 to be made, considered to be the primary parameter defining the scale size of the system. The best-fit model parameters from these passes are then employed to determine how the parameters vary with R1, using least-squares linear fits, thus providing predictive model parameters for any value of R1 within the range. We show that the fits obtained using the linear approximation parameters are of the same order as those for the individually selected parameters. We also show that the magnetic flux mapping to the tail lobes in these models is generally in good accord with observations of the location of the open-closed field line boundary in Saturn's ionosphere, and the related position of the auroral oval. We then investigate the field data on six passes through the nightside magnetosphere, for which the spacecraft did not cross the magnetopause, such that in this case we compare the

  16. Relevance of Postoperative Magnetic Resonance Images in Evaluating Epidural Hematoma After Thoracic Fixation Surgery.

    Science.gov (United States)

    Shin, Hong Kyung; Choi, Il; Roh, Sung Woo; Rhim, Seung Chul; Jeon, Sang Ryong

    2017-11-01

    It is difficult to evaluate the significant findings of epidural hematoma in magnetic resonance images (MRIs) obtained immediately after thoracic posterior screw fixation (PSF). Prospectively, immediate postoperative MRI was performed in 10 patients who underwent thoracic PSF from April to December 2013. Additionally, we retrospectively analyzed the MRIs from 3 patients before hematoma evacuation out of 260 patients who underwent thoracic PSF from January 2000 to March 2013. The MRI findings of 9 out of the 10 patients, consecutively collected after thoracic PSF, showed neurologic recovery with a well-preserved cerebrospinal fluid (CSF) space and no prominent hemorrhage. Even though there were metal artifacts at the level of the pedicle screws, the preserved CSF space was observed. In contrast, the MRI of 1 patient with poor neurologic outcome demonstrated a typical hematoma and slight spinal cord compression and reduced CSF space. In the retrospective analysis of the 3 patients who showed definite motor weakness in the lower extremities after their first thoracic fusion surgery and underwent hematoma evacuation, the magnetic resonance images before hematoma evacuation also revealed hematoma compressing the spinal cord and diminished CSF space. This study shows that epidural hematomas can be detected on MRI performed immediately after thoracic fixation surgery, despite metal artifacts and findings such as hematoma causing spinal cord compression. Loss of CSF space should be considered to be associated with neurologic deficit. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Atmospheric pollution history at Linfen (China) uncovered by magnetic and chemical parameters of sediments from a water reservoir.

    Science.gov (United States)

    Ma, Mingming; Hu, Shouyun; Cao, Liwan; Appel, Erwin; Wang, Longsheng

    2015-09-01

    We studied magnetic and chemical parameters of sediments from sediments of a water reservoir at Linfen (China) in order to quantitatively reconstruct the atmospheric pollution history in this region. The results show that the main magnetic phases are magnetite and maghemite originating from the surrounding catchment and from anthropogenic activities, and there is a significant positive relationship between magnetic concentration parameters and heavy metals concentrations, indicating that magnetic proxies can be used to monitor the anthropogenic pollution. In order to uncover the atmospheric pollution history, we combined the known events of environmental improvement with variations of magnetic susceptibility (χ) and heavy metals along the cores to obtain a detailed chronological framework. In addition, air comprehensive pollution index (ACPI) was reconstructed from regression equation among magnetic and chemical parameters as well as atmospheric monitoring data. Based on these results, the atmospheric pollution history was successfully reconstructed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Investigation of electromagnetic interference effects by ESD simulator on test parameters of tunneling magnetic recording heads

    Energy Technology Data Exchange (ETDEWEB)

    Kruesubthaworn, A., E-mail: anankr@kku.ac.th [KKU-Seagate Cooperation Research Laboratory, Department of Electrical Engineering, Khon Kaen University, Khon Kaen 40002 (Thailand); Khunkitti, P.; Siritaratiwat, A.; Kaewrawang, A. [KKU-Seagate Cooperation Research Laboratory, Department of Electrical Engineering, Khon Kaen University, Khon Kaen 40002 (Thailand); Mewes, T.; Mewes, C.K.A. [Department of Physics and Astronomy, MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States)

    2017-01-01

    Electrostatic discharge (ESD) has been an important issue in the manufacturing processes of hard disk drive. It can also generate electromagnetic interference (EMI) which could possibly damage magnetic recording heads. The aims of this work are to measure the EMI from ESD events and to examine the effects of EMI on the heads. The discharge current and the EMI generated by an ESD simulator were experimentally measured. Also, the EMI was applied to the heads to determine if this can cause changes of head parameters. Our results show that the discharge current waveform is consistent with the theoretical waveform of the IEC ESD standard. Additionally, we found that the EMI applied due to ESD at distances greater than 2 cm does not have any significant effect on the head parameters. Hence, further detailed experiments are proposed to evaluate the EMI effects on recording head parameters in order to improve the measurement methodologies to prevent the degradation of the heads performance and to increase the robustness of the heads. - Highlights: • The electrostatic discharge (ESD) has been an important issue for the hard disk drive. • The electromagnetic interference (EMI) radiated by ESD IEC 61000-4-2 was focused. • Effects of the EMI on the magnetic recording head were examined. • The change of parameters of the writer and reader due to the EMI was measured. • The EMI could not cause any significant affectation on the writer and reader.

  19. Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

    Science.gov (United States)

    Waindok, Andrzej; Piekielny, Paweł

    2017-10-01

    The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V) and capacitance value (60 mF to 340.5 mF) were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

  20. Reactor-relevant quiescent H-mode operation using torque from non-axisymmetric, non-resonant magnetic fields

    International Nuclear Information System (INIS)

    Burrell, K. H.; Garofalo, A. M; Osborne, T. H.; Schaffer, M. J.; Snyder, P. B.; Solomon, W. M.; Park, J.-K.; Fenstermacher, M. E.

    2012-01-01

    Results from recent experiments demonstrate that quiescent H-mode (QH-mode) sustained by magnetic torque from non-axisymmetric magnetic fields is a promising operating mode for future burning plasmas. Using magnetic torque from n=3 fields to replace counter-I p torque from neutral beam injection (NBI), we have achieved long duration, counter-rotating QH-mode operation with NBI torque ranging from counter-I p to up to co-I p values of 1-1.3 Nm. This co-I p torque is 3 to 4 times the scaled torque that ITER will have. These experiments utilized an ITER-relevant lower single-null plasma shape and were done with ITER-relevant values of ν ped * and β N ped . These discharges exhibited confinement quality H 98y2 =1.3, in the range required for ITER. In preliminary experiments using n=3 fields only from a coil outside the toroidal coil, QH-mode plasmas with low q 95 =3.4 have reached fusion gain values of G=β N H 89 /q 95 2 =0.4, which is the desired value for ITER. Shots with the same coil configuration also operated with net zero NBI torque. The limits on G and co-I p torque have not yet been established for this coil configuration. QH-mode work to has made significant contact with theory. The importance of edge rotational shear is consistent with peeling-ballooning mode theory. Qualitative and quantitative agreements with the predicted neoclassical toroidal viscosity torque is seen.

  1. Test-bench for characterization of steady state magnetic sensors parameters in wide temperature range

    International Nuclear Information System (INIS)

    Kovařík, Karel; Ďuran, Ivan; Sentkerestiová, Jana; Šesták, David

    2013-01-01

    Highlights: •Prepared test bench for calibration of steady state magnetic sensors. •Test-bench design optimized for calibration up to 300 °C. •Test-bench is remotely controllable and allows long term measurements. •Construction allows easy manipulation with even irradiated samples. -- Abstract: Magnetic sensors in ITER tokamak and in other future fusion devices will face an environment with temperature often elevated well above 200 °C. Dedicated test benches are needed to allow characterization of performance of magnetic sensors at such elevated temperatures. This contribution describes realization of test bench for calibration of steady state magnetic sensors based on Hall effect. The core of the set-up is the coil providing DC calibration magnetic field. Optimization of coils design to ensure its compatibility with elevated temperature up to 300 °C is described. Optimized coil was manufactured, and calibrated both at room temperature and at temperature of 250 °C. Measured calibration magnetic field of the coil biased by a 30 A commercial laboratory power supplies is 224 mT. The coil is supplemented by PID regulated air cooling system for fine control of sensors temperature during measurements. Data acquisition system is composed from PC A/D converter boards with resolution below 1 μV. The key parameters of the test bench are remotely controllable and the system allows long term continuous measurements including tests of irradiated samples. The performance of the test bench is demonstrated on recent measurements with metal Hall sensors based on thin copper sensing layers

  2. The Influence of the Axial Magnetic Field Upon- the Coaxial Plasma Gun Parameters

    International Nuclear Information System (INIS)

    El-Aragi, G.M.; El-Demardash, A.

    2001-01-01

    This study concerns with the influence of an applied axial magnetic field upon the electrical parameters and on the brightness (luminance) of argon plasma. The brightness was measured by with a photomultiplier type of IP28 RCA. The experimental results are investigated with plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied. It was found that the thickness of skin-layer δ about 0.01 cm and the wavelength λ, of the perturbation about 1.3 cm i.e. the instability has been satisfied. The growth rate γ of the instability about 10 6 sec -1 . (author)

  3. Quantification of the lift height for magnetic force microscopy using 3D surface parameters

    International Nuclear Information System (INIS)

    Nenadovic, M.; Strbac, S.; Rakocevic, Z.

    2010-01-01

    In this work, the quantitative conditions for the lift height for imaging of the magnetic field using magnetic force microscopy (MFM) were optimized. A thin cobalt film deposited on a monocrystalline silicon (1 0 0) substrate with a thickness of 55 nm and a thin nickel film deposited on a glass with a thickness of 600 nm were used as samples. The topography of the surface was acquired by tapping mode atomic force microscopy (AFM), while MFM imaging was performed in the lift mode for various lift heights. It was determined that the sensitivity of the measurements was about 10% higher for images obtained at a scan angle of 90 o compared to a scan angle of 0 deg. Therefore, the three-dimensional surface texture parameters, i.e., average roughness, skewness, kurtosis and the bearing ratio, were determined in dependence on the lift height for a scan angle of 90 deg. The results of the analyses of the surface parameters showed that the influence of the substrate and its texture on the magnetic force image could be neglected for lift heights above 40 nm and that the upper lift height limit is 100 nm. It was determined that the optimal values of the lift heights were in the range from 60 to 80 nm, depending on the nature of the sample and on the type of the tip used.

  4. Ring current and auroral electrojets in connection with interplanetary medium parameters during magnetic storm

    Directory of Open Access Journals (Sweden)

    Y. I. Feldstein

    Full Text Available The relationship between the auroral electrojet indices (AE and the ring current magnetic field (DR was investigated by observations obtained during the magnetic storm on 1-3 April 1973. During the storm main phase the DR development is accompanied by a shift of the auroral electrojets toward the equator. As a result, the standard AE indices calculated on the basis of data from auroral observatories was substantially lower than the real values (AE'. To determine AE' during the course of a storm main phase data from subauroral magnetic observatories should be used. It is shown that the intensity of the indices (AE' which take into account the shift of the electrojets is increased substantially relative to the standard indices during the storm main phase. AE' values are closely correlated with geoeffective solar wind parameters. A high correlation was obtained between AE' and the energy flux into the ring current during the storm main phase. Analysis of magnetic field variations during intervals with intense southward IMF components demonstrates a decrease of the saturation effect of auroral electrojet currents if subauroral stations magnetic field variations are taken into account. This applies both to case studies and statistical data. The dynamics of the electrojets in connection with the development of the ring current and of magnetospheric substorms can be described by the presence (absence of saturation for minimum (maximum AE index values during a 1-h interval. The ring current magnetic field asymmetry (ASY was calculated as the difference between the maximum and minimum field values along a parallel of latitude at low latitudes. The ASY value is closely correlated with geoeffective solar wind parameters and simultaneously is a more sensitive indicator of IMF Bz variations than the symmetric ring current.

  5. Optimization of the protective energy removal parameters for tokamak HT7-U superconducting magnets

    Energy Technology Data Exchange (ETDEWEB)

    Khvostenko, P.P.; Chudnovsky, A.N.; Posadsky, I.A. [RRC ' Kurchatov Inst.' , Nuclear Fusion Inst., Moscow (Russian Federation); Bi, Y.F.; Cheng, S.M.; He, Y.X. [Academia Sinica, Hefei, Anhui (China). Inst. of Plasma Physics

    1998-07-01

    The design of the HT-7U superconducting tokamak is in progress now. The design incorporates superconducting magnets of the toroidal field and poloidal field systems. Toroidal field system consists of 16 D-shape coils and poloidal field system consists of 12 coils. All coils will be use NbTi/Cu cable-in-conduit conductor cooled with forced-flow supercritical helium at 4.5 K, 4 Bar. Quench in the superconducting magnets is accompanied byconversion of the stored magnetic field energy into a thermal one which is spent on heating of both the coil part which made transition into a normal state and dump resistors. A non-uniform heating of the coil part results in the emergence of thermomechanical stresses which can cause its destruction. The protective removal of a current is realized to prevent the coil destruction at the emergence of the quench. In that case, the faster the current removal occurs, the less the coil heating is. On the other hand, the current removal rate should not be too high in order to avoid an electric breakdown by the excited inductive voltage. Optimization of the protective energy removal parameters both for TF and PF superconducting magnets is presented. (author)

  6. Optimization of the protective energy removal parameters for tokamak HT7-U superconducting magnets

    International Nuclear Information System (INIS)

    Khvostenko, P.P.; Chudnovsky, A.N.; Posadsky, I.A.; Bi, Y.F.; Cheng, S.M.; He, Y.X.

    1998-01-01

    The design of the HT-7U superconducting tokamak is in progress now. The design incorporates superconducting magnets of the toroidal field and poloidal field systems. Toroidal field system consists of 16 D-shape coils and poloidal field system consists of 12 coils. All coils will be use NbTi/Cu cable-in-conduit conductor cooled with forced-flow supercritical helium at 4.5 K, 4 Bar. Quench in the superconducting magnets is accompanied by conversion of the stored magnetic field energy into a thermal one which is spent on heating of both the coil part which made transition into a normal state and dump resistors. A non-uniform heating of the coil part results in the emergence of thermomechanical stresses which can cause its destruction. The protective removal of a current is realized to prevent the coil destruction at the emergence of the quench. In that case, the faster the current removal occurs, the less the coil heating is. On the other hand, the current removal rate should not be too high in order to avoid an electric breakdown by the excited inductive voltage. Optimization of the protective energy removal parameters both for TF and PF superconducting magnets is presented. (author)

  7. The Numerical Calculation and Experimental Measurement of the Inductance Parameters for Permanent Magnet Synchronous Motor in Electric Vehicle

    Science.gov (United States)

    Jiang, Chao; Qiao, Mingzhong; Zhu, Peng

    2017-12-01

    A permanent magnet synchronous motor with radial magnetic circuit and built-in permanent magnet is designed for the electric vehicle. Finite element numerical calculation and experimental measurement are adopted to obtain the direct axis and quadrature axis inductance parameters of the motor which are vital important for the motor control. The calculation method is simple, the measuring principle is clear, the results of numerical calculation and experimental measurement are mutual confirmation. A quick and effective method is provided to obtain the direct axis and quadrature axis inductance parameters of the motor, and then improve the design of motor or adjust the control parameters of the motor controller.

  8. Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions

    KAUST Repository

    Yeo, Siang Yee; Choi, Siwon; Dien, Vivian; Sow-Peh, Yoke Keow; Qi, Genggeng; Hatton, T. Alan; Doyle, Patrick S.; Thio, Beng Joo Reginald

    2013-01-01

    We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb2+) ions from water. Magnetite-waste tea composites were dispersed in four different types of water–deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater–that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16–5.55 ppm) of Pb2+ ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb2+ ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ~70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb2+ ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.

  9. Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions

    KAUST Repository

    Yeo, Siang Yee

    2013-06-20

    We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb2+) ions from water. Magnetite-waste tea composites were dispersed in four different types of water–deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater–that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16–5.55 ppm) of Pb2+ ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb2+ ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ~70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb2+ ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.

  10. Study on spatial distribution of plasma parameters in a magnetized inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Hee-Woon; Lee, Woohyun; Kim, Ji-Won; Whang, Ki-Woong, E-mail: kwhang@snu.ac.kr [Plasma Laboratory, Inter-University Semiconductor Research Center, Department of Electrical and Computer Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Hyuk [Samsung Electronics Co., Banwol-dong, Hwaseong 445-701 (Korea, Republic of); Park, Wanjae [Tokyo Electron Miyagi Ltd., Taiwa-cho, Kurokawa-gun, Miyagi 981-3629 (Japan)

    2015-07-15

    Spatial distributions of various plasma parameters such as plasma density, electron temperature, and radical density in an inductively coupled plasma (ICP) and a magnetized inductively coupled plasma (M-ICP) were investigated and compared. Electron temperature in between the rf window and the substrate holder of M-ICP was higher than that of ICP, whereas the one just above the substrate holder of M-ICP was similar to that of ICP when a weak (<8 G) magnetic field was employed. As a result, radical densities in M-ICP were higher than those in ICP and the etch rate of oxide in M-ICP was faster than that in ICP without severe electron charging in 90 nm high aspect ratio contact hole etch.

  11. Calculation of electromagnetic constitutive parameters of insulating magnetic materials with conducting inclusions

    Energy Technology Data Exchange (ETDEWEB)

    Kuster, E.; Moore, R.; Lust, L.; Kemper, P. [Georgia Inst. of Tech., Atlanta, GA (United States)

    1996-12-31

    A Method of Moments (MoM) electromagnetic model of percolating conducting films was applied to calculate the effective parameters of the composite formed by conducting inclusions placed within a dispersive magnetic but nondispersive dielectric matrix. The MoM calculations demonstrate a coupling between the magnetic properties of the matrix and the effective composite permittivity and frequency dispersion of the composite. The coupling of permittivity and permeability is observed near the percolation threshold of the composite and for high conductivity inclusions. The prediction agrees with physical expectations since near percolation the conduction correlation length dominates the effective permittivity of the composite and this correlation length is determined by both the permittivity and permeability of the composite.

  12. Clinically relevant magnetic resonance imaging (MRI findings in elite swimmers’ shoulders

    Directory of Open Access Journals (Sweden)

    Arno Celliers

    2017-01-01

    Objective: To assess clinically relevant MRI findings in the shoulders of symptomatic and asymptomatic elite swimmers. Method: Twenty (aged 16–23 years elite swimmers completed questionnaires on their swimming training, pain and shoulder function. MRI of both shoulders (n = 40 were performed and all swimmers were given a standardised clinical shoulder examination. Results: Both shoulders of 11 male and 9 female elite swimmers (n = 40 were examined. Eleven of the 40 shoulders were clinically symptomatic and 29 were asymptomatic. The most common clinical finding in both the symptomatic and asymptomatic shoulders was impingement during internal rotation, with impingement in 54.5% of the symptomatic shoulders and in 31.0% of the asymptomatic shoulders. The most common MRI findings in the symptomatic and asymptomatic shoulders were supraspinatus tendinosis (45.5% vs. 20.7%, subacromial subdeltoid fluid (45.5% vs. 34.5%, increased signal in the AC Joint (45.5% vs. 37.9% and AC joint arthrosis (36.4% vs. 34.5%. Thirty-nine (97.5% of the shoulders showed abnormal MRI features. Conclusion: MRI findings in the symptomatic and asymptomatic shoulders of young elite swimmers are similar and care should be taken when reporting shoulder MRIs in these athletes. Asymptomatic shoulders demonstrate manifold MRI abnormalities that may be radiologically significant but appear not to be clinically significant.

  13. Low virial parameters in molecular clouds: Implications for high-mass star formation and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Kauffmann, Jens; Pillai, Thushara [Astronomy Department, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Goldsmith, Paul F., E-mail: jens.kauffmann@astro.caltech.edu, E-mail: tpillai@astro.caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States)

    2013-12-20

    Whether or not molecular clouds and embedded cloud fragments are stable against collapse is of utmost importance for the study of the star formation process. Only 'supercritical' cloud fragments are able to collapse and form stars. The virial parameter α = M {sub vir}/M, which compares the virial mass to the actual mass, provides one way to gauge stability against collapse. Supercritical cloud fragments are characterized by α ≲ 2, as indicated by a comprehensive stability analysis considering perturbations in pressure and density gradients. Past research has suggested that virial parameters α ≳ 2 prevail in clouds. This would suggest that collapse toward star formation is a gradual and relatively slow process and that magnetic fields are not needed to explain the observed cloud structure. Here, we review a range of very recent observational studies that derive virial parameters <<2 and compile a catalog of 1325 virial parameter estimates. Low values of α are in particular observed for regions of high-mass star formation (HMSF). These observations may argue for a more rapid and violent evolution during collapse. This would enable 'competitive accretion' in HMSF, constrain some models of 'monolithic collapse', and might explain the absence of high-mass starless cores. Alternatively, the data could point at the presence of significant magnetic fields ∼1 mG at high gas densities. We examine to what extent the derived observational properties might be biased by observational or theoretical uncertainties. For a wide range of reasonable parameters, our conclusions appear to be robust with respect to such biases.

  14. A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

    Science.gov (United States)

    Zourmand, Alireza; Mirhassani, Seyed Mostafa; Ting, Hua-Nong; Bux, Shaik Ismail; Ng, Kwan Hoong; Bilgen, Mehmet; Jalaludin, Mohd Amin

    2014-07-25

    The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

  15. Magnetism and Hyperfine Parameters in Iron Rich Gd_2Fe_{17-x}Si_x Intermetallics

    Science.gov (United States)

    Nouri, K.; Bartoli, T.; Chrobak, A.; Moscovici, J.; Bessais, L.

    2018-04-01

    Gd_2Fe_{17-x}Si_x (x = 0.25 , 0.5 and 1) samples were synthesized by arc melting and annealed at 1073 K for 1 week. X-ray diffraction analysis by the Rietveld method has shown that these materials crystallize in the rhombohedral Th_2Zn_{17} -type structure (space group R\\bar{3}m ). The Curie temperature increases with Si content x, whereas the unit-cell parameters decrease slightly. The temperature dependence of magnetization data revealed that Gd_2Fe_{17-x}Si_x exhibits a second-order ferromagnetic to paramagnetic phase transition in the vicinity of the Curie temperature. Exchange coupling parameters of R-R, M-M and R-M (R—rare earth, M—transition metal) have been determined from M(T) magnetization curves based on the mean field theory calculation. The magnetic entropy change Δ S_M and the relative cooling power were estimated from isothermal magnetization curves for all samples. In the proximity of {T}_C and in an applied field of 1.56 T, Δ S_M reached a maximum values of 1.38, 1.67 and 3.07 J/kg K for x = 0.25, 0.5 and 1, respectively. We have calculated the magnetic moment per Fe atom from magnetization measurements at 293 K up to 17 kOe, and it decreases with Si content. These results are verified by the Mössbauer spectrometry measurements obtained at the same temperature. The Mössbauer spectra analysis is based on the correlation between the Wigner-Seitz volume and the isomer-shift evolution of each specific site 6c, 9d, 18f, and 18h of the R\\bar{3} m structure. For all Si concentrations, the magnitude of the hyperfine fields are {H_HF}{6c} > {H_HF}{9d} > {H_HF}{18f} > {H_HF}{18h} . The mean hyperfine field decreases with the Si content.

  16. Relativistic theory of nuclear magnetic resonance parameters in a Gaussian basis representation

    International Nuclear Information System (INIS)

    Kutzelnigg, Werner; Liu Wenjian

    2009-01-01

    The calculation of NMR parameters from relativistic quantum theory in a Gaussian basis expansion requires some care. While in the absence of a magnetic field the expansion in a kinetically balanced basis converges for the wave function in the mean and for the energy with any desired accuracy, this is not necessarily the case for magnetic properties. The results for the magnetizability or the nuclear magnetic shielding are not even correct in the nonrelativistic limit (nrl) if one expands the original Dirac equation in a kinetically balanced Gaussian basis. This defect disappears if one starts from the unitary transformed Dirac equation as suggested by Kutzelnigg [Phys. Rev. A 67, 032109 (2003)]. However, a new difficulty can arise instead if one applies the transformation in the presence of the magnetic field of a point nucleus. If one decomposes certain contributions, the individual terms may diverge, although their sum is regular. A controlled cancellation may become difficult and numerical instabilities can arise. Various ways exist to avoid these singularities and at the same time get the correct nrl. There are essentially three approaches intermediate between the transformed and the untransformed formulation, namely, the bispinor decomposition, the decomposition of the lower component, and the hybrid unitary transformation partially at operator and partially at matrix level. All three possibilities were first considered by Xiao et al. [J. Chem. Phys. 126, 214101 (2007)] in a different context and in a different nomenclature. Their analysis and classification in a more general context are given here for the first time. Use of an extended balanced basis has no advantages and has other drawbacks and is not competitive, while the use of a restricted magnetic balance basis can be justified.

  17. Parameter Estimation of Permanent Magnet Synchronous Motor Using Orthogonal Projection and Recursive Least Squares Combinatorial Algorithm

    Directory of Open Access Journals (Sweden)

    Iman Yousefi

    2015-01-01

    Full Text Available This paper presents parameter estimation of Permanent Magnet Synchronous Motor (PMSM using a combinatorial algorithm. Nonlinear fourth-order space state model of PMSM is selected. This model is rewritten to the linear regression form without linearization. Noise is imposed to the system in order to provide a real condition, and then combinatorial Orthogonal Projection Algorithm and Recursive Least Squares (OPA&RLS method is applied in the linear regression form to the system. Results of this method are compared to the Orthogonal Projection Algorithm (OPA and Recursive Least Squares (RLS methods to validate the feasibility of the proposed method. Simulation results validate the efficacy of the proposed algorithm.

  18. Objective image quality parameters of relevance in practice, measured for film-screen combinations - a contribution to quality assurance activities

    International Nuclear Information System (INIS)

    Angerstein, W.; Wolf, M.

    1986-01-01

    Objective measurement of the physico-technical parameters determining the image quality is the fastest and most accurate method of quality testing of the systems. The parameters in case of X-ray intensifying screens are imaging quality, servicable life, and mechanical properties. (orig./DG) [de

  19. Behaviour of the order parameter of the simple magnet in an external field

    Directory of Open Access Journals (Sweden)

    M.P.Kozlovskii

    2005-01-01

    Full Text Available The effect of a homogeneous external field on the three-dimensional uniaxial magnet behaviour near the critical point is investigated within the framework of the nonperturbative collective variables method using the ρ4 model. The research is carried out for the low-temperature region. The analytic explicit expressions for the free energy, average spin moment and susceptibility are obtained for weak and strong fields in comparison with the field value belonging to the pseudocritical line. The calculations are performed on the microscopic level without any adjusting parameters. It is established that the long-wave fluctuations of the order parameter play a crucial role in forming a crossover between the temperature-dependence and field-dependence critical behaviour of the system.

  20. Experimental Platform for measuring the parameters of magnetization of a transformer in a quasi-static transitional regime

    International Nuclear Information System (INIS)

    Milovanski, Vasil; , Blagoevgrad (Bulgaria))" data-affiliation=" (HMS “Acad. S. P. Corolov, Blagoevgrad (Bulgaria))" >Stoyanov, Krasimir; Milovanska, Stefani

    2013-01-01

    Some opportunities for development of an experimental module for magnetic research have been examined in the current paper. The goal is to attain a more accurate reading of the measured electrical signals which are directly related to the magnetic parameters and characteristics of the ferromagnetic material

  1. Functional Relevance of Coronary Artery Disease by Cardiac Magnetic Resonance and Cardiac Computed Tomography: Myocardial Perfusion and Fractional Flow Reserve

    Directory of Open Access Journals (Sweden)

    Gianluca Pontone

    2015-01-01

    Full Text Available Coronary artery disease (CAD is one of the leading causes of morbidity and mortality and it is responsible for an increasing resource burden. The identification of patients at high risk for adverse events is crucial to select those who will receive the greatest benefit from revascularization. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but the diagnostic yield of elective invasive coronary angiography remains unfortunately low. Stress myocardial perfusion imaging by cardiac magnetic resonance (stress-CMR has emerged as an accurate technique for diagnosis and prognostic stratification of the patients with known or suspected CAD thanks to high spatial and temporal resolution, absence of ionizing radiation, and the multiparametric value including the assessment of cardiac anatomy, function, and viability. On the other side, cardiac computed tomography (CCT has emerged as unique technique providing coronary arteries anatomy and more recently, due to the introduction of stress-CCT and noninvasive fractional flow reserve (FFR-CT, functional relevance of CAD in a single shot scan. The current review evaluates the technical aspects and clinical experience of stress-CMR and CCT in the evaluation of functional relevance of CAD discussing the strength and weakness of each approach.

  2. Sensitive parameters' optimization of the permanent magnet supporting mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongguang; Gao, Xiaohui; Wang, Yixuan; Yang, Xiaowei [Beihang University, Beijing (China)

    2014-07-15

    The fast development of the ultra-high speed vertical rotor promotes the study and exploration for the supporting mechanism. It has become the focus of research that how to improve the speed and overcome the vibration when the rotors pass through the low-order critical frequencies. This paper introduces a kind of permanent magnet (PM) supporting mechanism and describes an optimization method of its sensitive parameters, which can make the vertical rotor system reach 80000 r/min smoothly. Firstly we find the sensitive parameters through analyzing the rotor's features in the process of achieving high-speed, then, study these sensitive parameters and summarize the regularities with the method of combining the experiment and the finite element method (FEM), at last, achieve the optimization method of these parameters. That will not only get a stable effect of raising speed and shorten the debugging time greatly, but also promote the extensive application of the PM supporting mechanism in the ultra-high speed vertical rotors.

  3. PARAMETERS OF NUCLEAR MAGNETIC RESONANCE IN PATIENTS WITH CONGENITAL NARROWING OF THE LUMBAR SPINAL CANAL

    Directory of Open Access Journals (Sweden)

    ELIU HAZAEL MORALES-RANGEL

    Full Text Available ABSTRACT Objective: To compare the morphological parameters of magnetic resonance in patients with congenital narrowing of the lumbar spinal canal with patients with low back pain. Methods: A descriptive, retrospective, observational study was conducted with measurements in the axial and sagittal magnetic resonance sections of the vertebral body and canal of the lumbar spine of 64 patients with diagnosis of low back pain, which were compared with resonance images taken from 31 Mexican patients with congenital narrowing of the lumbar spinal canal. Results: The results show that patients with congenital narrowing of the lumbar spinal canal in the axial sections have a difference in diameters, being L2<13.9 mm, L3<13.3 mm, L4<12.9 mm, L5<13.1 mm, compared with controls L2<20.5 mm, L3<20.5 mm, L4<19.3 mm, L5<18.1 mm with p = 0.000. Conclusions: We found different measurements in the Mexican population compared to those found by similar studies. With the parameters obtained, it would be possible to make the proper diagnosis, surgical planning, and treatment.

  4. Iron-borosilicate soft magnetic composites: The correlation between processing parameters and magnetic properties for high frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Gheiratmand, T., E-mail: t.gheiratmand@yahoo.com; Madaah Hosseini, H.R., E-mail: Madaah@sharif.edu; Seyed Reihani, S.M.

    2017-05-01

    Iron-borosilicate soft magnetic composites are suitable magnetic materials for high temperature and high frequency applications. In this research two different techniques have been applied to fabricate these composites: uniaxial pressing following by sintering and spark plasma sintering. Different processing parameters including the content of borosilicate, the amount of compaction pressure and the size of iron particles have been evaluated through the study of microstructure and magnetic properties. The microstructural observations showed that the borosilicate is distributed on the iron grain boundaries enhancing the resistivity and causing the loss of eddy currents. Increasing the compaction pressure was led to the decrease of electrical resistivity. By increasing the frequency both real and imaginary parts of permeability decreased. The use of higher content of borosilicate resulted in the lower decreasing slop of permeability. Best combination of density, permeability and electrical resistivity was obtained in the sample with 2 wt% of borosilicate. In addition, the densification of powders with fine particles was more difficult than coarse particles due to the inter particles friction and bridging effects. Furthermore, as the particles size increases the size of open porosities before sintering where the borosilicate could aggregate enhances. This could yields to the increase in the electrical resistivity. The high ratio of surface to the volume in the powders with fine particles results in the developing the demagnetizing fields and subsequently, decreasing the permeability. The highest relative density (99.99% of theoretical density) with best distribution of borosilicate was achieved in the composites produced by spark plasma sintering (SPS). The relaxation frequency, obtained from imaginary part of permeability, was found as 340 Hz in the composites made by SPS. - Highlights: • Iron-borosilicate SMC was produced for high temperature and frequency

  5. Atmospheric pollution history at Linfen (China) uncovered by magnetic and chemical parameters of sediments from a water reservoir

    International Nuclear Information System (INIS)

    Ma, Mingming; Hu, Shouyun; Cao, Liwan; Appel, Erwin; Wang, Longsheng

    2015-01-01

    We studied magnetic and chemical parameters of sediments from sediments of a water reservoir at Linfen (China) in order to quantitatively reconstruct the atmospheric pollution history in this region. The results show that the main magnetic phases are magnetite and maghemite originating from the surrounding catchment and from anthropogenic activities, and there is a significant positive relationship between magnetic concentration parameters and heavy metals concentrations, indicating that magnetic proxies can be used to monitor the anthropogenic pollution. In order to uncover the atmospheric pollution history, we combined the known events of environmental improvement with variations of magnetic susceptibility (χ) and heavy metals along the cores to obtain a detailed chronological framework. In addition, air comprehensive pollution index (ACPI) was reconstructed from regression equation among magnetic and chemical parameters as well as atmospheric monitoring data. Based on these results, the atmospheric pollution history was successfully reconstructed. - Highlights: • Magnetic proxies can be used to monitor the heavy mental pollution in sediments. • Accurate age model was obtained using known events of environmental improvement. • Regression equation was obtained among sediment records and monitoring data. • Atmospheric pollution history was quantitatively reconstructed. - Atmospheric pollution history was quantitatively reconstructed using magnetic and chemical records of reservoir sediments combined with atmospheric monitoring data

  6. Influence of the power supply parameters on the projectile energy in the permanent magnet electrodynamic accelerator

    Directory of Open Access Journals (Sweden)

    Waindok Andrzej

    2017-01-01

    Full Text Available The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V and capacitance value (60 mF to 340.5 mF were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

  7. Transcranial magnetic stimulation (TMS): compared sensitivity of different motor response parameters in ALS.

    Science.gov (United States)

    Pouget, J; Trefouret, S; Attarian, S

    2000-06-01

    Owing to the low sensitivity of clinical signs in assessing upper motor neuron (UMN) involvement in ALS, there is a need for investigative tools capable of detecting abnormal function of the pyramidal tract. Transcranial magnetic stimulation (TMS) may contribute to the diagnosis by reflecting a UMN dysfunction that is not clinically detectable. Several parameters for the motor responses to TMS can be evaluated with different levels of significance in healthy subjects compared with ALS patients. The central motor conduction time, however, is not sensitive in detecting subclinical UMN defects in individual ALS patients. The amplitude of the motor evoked potential (MEP), expressed as the percentage of the maximum wave, also has a low sensitivity. In some cases, the corticomotor threshold is decreased early in the disease course as a result of corticomotor neuron hyperexcitability induced by glutamate. Later, the threshold increases, indicating a loss of UMN. In our experience, a decreased silent period duration appears to be the most sensitive parameter when using motor TMS in ALS. TMS is also a sensitive technique for investigating the corticobulbar tract, which is difficult to study by other methods. TMS is a widely available, painless and safe technique with a good sensitivity that can visualize both corticospinal and corticobulbar tract abnormalities. The sensitivity can be improved further by taking into account the several MEP parameters, including latency and cortical silent period decreased duration.

  8. Deriving amplification factors from simple site parameters using generalized regression neural networks: implications for relevant site proxies

    Science.gov (United States)

    Boudghene Stambouli, Ahmed; Zendagui, Djawad; Bard, Pierre-Yves; Derras, Boumédiène

    2017-07-01

    Most modern seismic codes account for site effects using an amplification factor (AF) that modifies the rock acceleration response spectra in relation to a "site condition proxy," i.e., a parameter related to the velocity profile at the site under consideration. Therefore, for practical purposes, it is interesting to identify the site parameters that best control the frequency-dependent shape of the AF. The goal of the present study is to provide a quantitative assessment of the performance of various site condition proxies to predict the main AF features, including the often used short- and mid-period amplification factors, Fa and Fv, proposed by Borcherdt (in Earthq Spectra 10:617-653, 1994). In this context, the linear, viscoelastic responses of a set of 858 actual soil columns from Japan, the USA, and Europe are computed for a set of 14 real accelerograms with varying frequency contents. The correlation between the corresponding site-specific average amplification factors and several site proxies (considered alone or as multiple combinations) is analyzed using the generalized regression neural network (GRNN). The performance of each site proxy combination is assessed through the variance reduction with respect to the initial amplification factor variability of the 858 profiles. Both the whole period range and specific short- and mid-period ranges associated with the Borcherdt factors Fa and Fv are considered. The actual amplification factor of an arbitrary soil profile is found to be satisfactorily approximated with a limited number of site proxies (4-6). As the usual code practice implies a lower number of site proxies (generally one, sometimes two), a sensitivity analysis is conducted to identify the "best performing" site parameters. The best one is the overall velocity contrast between underlying bedrock and minimum velocity in the soil column. Because these are the most difficult and expensive parameters to measure, especially for thick deposits, other

  9. Excitonic magnet in external field: Complex order parameter and spin currents

    Science.gov (United States)

    Geffroy, D.; Hariki, A.; Kuneš, J.

    2018-04-01

    We investigate spin-triplet exciton condensation in the two-orbital Hubbard model close to half-filling by means of dynamical mean-field theory. Employing an impurity solver that handles complex off-diagonal hybridization functions, we study the behavior of excitonic condensate in stoichiometric and doped systems subject to external magnetic field. We find a general tendency of the triplet order parameter to lie perpendicular with the applied field and identify exceptions from this rule. For solutions exhibiting k -odd spin textures, we discuss the Bloch theorem, which, in the absence of spin-orbit coupling, forbids the appearance of spontaneous net spin current. We demonstrate that the Bloch theorem is not obeyed by the dynamical mean-field theory.

  10. Design of Parameter Independent, High Performance Sensorless Controllers for Permanent Magnet Synchronous Machines

    DEFF Research Database (Denmark)

    Xie, Ge

    . The transient fluctuation of the estimated rotor position error is around 20 degrees with a step load torque change from 0% to 100% of the rated torque. The position error in steady state is within ±2 electrical degrees for the best case. The proposed method may also be used for e.g. online machine parameter......The Permanent Magnet Synchronous Machine (PMSM) has become an attractive candidate for various industrial applications due to its high efficiency and torque density. In the PMSM drive system, simple and robust control methods play an important role in achieving satisfactory drive performances....... For reducing the cost and increasing the reliability of the drive system, eliminating the mechanical sensor brings a lot advantages to the PMSM drive system. Therefore, sensorless control was developed and has been increasingly used in different PMSM drive systems in the last 20 years. However, machine...

  11. The limits of the electron optical parameters of asymmetric double pipecol magnetic objective lenses

    International Nuclear Information System (INIS)

    Al-khashab, A. M.; Abas, K. A.

    1997-01-01

    The asymmetrical magnetic electron lens is of great importance for the electron microscopes intended for high resolution. Such lenses are determined not only by its geometric structure and shape parameters but also by the gap width to bore diameter (S/D) of its pole pieces. a systematic investigation has been carried out for asymmetric objective lenses having different bore diameters. The results indicate that the op per h ore diameter of pole piece lens has considerable effects on the electron optical properties. The Comparison between the two sets of the family of asymmetric lenses provides good performance, and suggests that the ratio of the lens gap width to the bore diameters of its pole pieces (S/ D 1 /D 2 =3) are favourable. (authors). 9 refs., 9 figs

  12. Relevant parameters in the micro silica selection for the self-flowing ultra-low cement castables production

    International Nuclear Information System (INIS)

    Studart, A.R.; Pandolfelli, V.C.; Rodrigues, J.A.; Vendrasco, S.L.

    1997-01-01

    Self-flowing ultra-low cement castables typically contain a large fraction of the particles, usually fume silica, which increase their flowability and mechanical strength at low temperatures. Fume silicas available in the market differ mainly from their amount of impurities. It is assumed that the content of soluble alkali and free carbon containing in this raw-material affects strongly the processing of self-flowing castable. In this work high alumina castables with gap-sized particle size distribution were prepared to evaluate their flowability, workability and mechanical strength for each sort of fume silica studied. It was observed that the amount of impurities affects both deflocculation and setting time of the castables and their cold and hot mechanical strength. Considerations regarding the physical and chemical characteristics relevant for selecting fume silicas for the production of self-flowing castables are presented and discussed. (author)

  13. Effects of dynamic diffraction conditions on magnetic parameter determination in a double perovskite Sr_2FeMoO_6 using electron energy-loss magnetic chiral dichroism

    International Nuclear Information System (INIS)

    Wang, Z.C.; Zhong, X.Y.; Jin, L.; Chen, X.F.; Moritomo, Y.; Mayer, J.

    2017-01-01

    Electron energy-loss magnetic chiral dichroism (EMCD) spectroscopy, which is similar to the well-established X-ray magnetic circular dichroism spectroscopy (XMCD), can determine the quantitative magnetic parameters of materials with high spatial resolution. One of the major obstacles in quantitative analysis using the EMCD technique is the relatively poor signal-to-noise ratio (SNR), compared to XMCD. Here, in the example of a double perovskite Sr_2FeMoO_6, we predicted the optimal dynamical diffraction conditions such as sample thickness, crystallographic orientation and detection aperture position by theoretical simulations. By using the optimized conditions, we showed that the SNR of experimental EMCD spectra can be significantly improved and the error of quantitative magnetic parameter determined by EMCD technique can be remarkably lowered. Our results demonstrate that, with enhanced SNR, the EMCD technique can be a unique tool to understand the structure-property relationship of magnetic materials particularly in the high-density magnetic recording and spintronic devices by quantitatively determining magnetic structure and properties at the nanometer scale. - Highlights: • We demonstrate how to choose the optimal experimental conditions by using dynamical diffraction calculations in Sr_2FeMoO_6. • With optimized diffraction conditions, the signal-to-noise ratio of experimental EMCD spectra has been significantly improved. • We have determined orbital to spin magnetic moment ratio of Sr_2FeMoO_6 quantitatively. • We have discussed the effects of dynamical diffraction conditions on the error bar of quantitative magnetic parameters.

  14. Male reproductive system parameters in a two-generation reproduction study of ammonium perfluorooctanoate in rats and human relevance.

    Science.gov (United States)

    York, Raymond G; Kennedy, Gerald L; Olsen, Geary W; Butenhoff, John L

    2010-04-30

    Ammonium perfluorooctanoate (ammonium PFOA) is an industrial surfactant that has been used primarily as a processing aid in the manufacture of fluoropolymers. The environmental and metabolic stability of PFOA together with its presence in human blood and long elimination half-life have led to extensive toxicological studies in laboratory animals. Two recent publications based on observations from the Danish general population have reported: (1) a negative association between serum concentrations of PFOA in young adult males and their sperm counts and (2) a positive association among women with time to pregnancy. A two-generation reproduction study in rats was previously published (2004) in which no effects on functional reproduction were observed at doses up to 30mg ammonium PFOA/kg body weight. The article contained the simple statement: "In males, fertility was normal as were all sperm parameters". In order to place the recent human epidemiological data in perspective, herein we provide the detailed male reproductive parameters from that study, including sperm quality and testicular histopathology. Sperm parameters in rats from the two-generation study in all ammonium PFOA treatment groups were unaffected by treatment with ammonium PFOA. These observations reflected the normal fertility observations in these males. No evidence of altered testicular and sperm structure and function was observed in ammonium PFOA-treated rats whose mean group serum PFOA concentrations ranged up to approximately 50,000ng/mL. Given that median serum PFOA in the Danish cohorts was approximately 5ng/mL, it seems unlikely that concentrations observed in the general population, including those recently reported in Danish general population, could be associated causally with a real decrement in sperm number and quality.

  15. The study of influence of relevant physical parameters variations on the estimates of the effective doses of Rn-222

    International Nuclear Information System (INIS)

    Ridzikova, A.; Fronka, A.; Moucka, L.

    2004-01-01

    Based on the analysis of 12 weekly continuous measurements and 4 integral measurements performed in different seasons in actual apartment rooms, bedrooms in particular, we attempted to identify the uncertainties that are involved in the estimation of radiation doses to lung tissues. We found that the parameters of time of residence, concentration, and equilibrium factor can affect substantially the estimate of the overall early effective dose. The weekly averaged concentration measured in one term is not sufficient for a fairly accurate estimate; actually, the equilibrium factor f must also be known and the actual real individual time of residence must be estimated if we want to adopt this approach to the dose estimation

  16. Determining superconducting parameters from analysis of magnetization fluctuation for CaLaBaCu3O7-δ superconductor

    International Nuclear Information System (INIS)

    Parra Vargas, C.A.; Landinez Tellez, D.A.; Roa-Rojas, J.

    2007-01-01

    In this work, we report analysis of magnetization fluctuations for the CaLaBaCu 3 O 7- δ superconducting system. We describe a procedure for extracting the penetration depth λ(T) and the coherence length ξ parameters from the magnetization, as a function of the applied magnetic field. This procedure takes the vortex fluctuation into account. The data of the magnetization excess ΔM(T) are analyzed for different values of temperature in the interval from 65 to 73 K. For several magnetic fields we observed a crossover in the magnetization curves at the characteristic temperature value T *=72.2 K. We calculated the data of magnetization excess from the curves of magnetization as a function of the logarithm of the applied field. This procedure was performed for polycrystalline samples of CaLaBaCu 3 O 7- δ by using the proposition of Bulaevskii, Ledvij and Kogan. We notice that the values for these superconducting parameters are in agreement with reports for high-temperature superconductors

  17. A simplified model for predicting malaria entomologic inoculation rates based on entomologic and parasitologic parameters relevant to control.

    Science.gov (United States)

    Killeen, G F; McKenzie, F E; Foy, B D; Schieffelin, C; Billingsley, P F; Beier, J C

    2000-05-01

    Malaria transmission intensity is modeled from the starting perspective of individual vector mosquitoes and is expressed directly as the entomologic inoculation rate (EIR). The potential of individual mosquitoes to transmit malaria during their lifetime is presented graphically as a function of their feeding cycle length and survival, human biting preferences, and the parasite sporogonic incubation period. The EIR is then calculated as the product of 1) the potential of individual vectors to transmit malaria during their lifetime, 2) vector emergence rate relative to human population size, and 3) the infectiousness of the human population to vectors. Thus, impacts on more than one of these parameters will amplify each other's effects. The EIRs transmitted by the dominant vector species at four malaria-endemic sites from Papua New Guinea, Tanzania, and Nigeria were predicted using field measurements of these characteristics together with human biting rate and human reservoir infectiousness. This model predicted EIRs (+/- SD) that are 1.13 +/- 0.37 (range = 0.84-1.59) times those measured in the field. For these four sites, mosquito emergence rate and lifetime transmission potential were more important determinants of the EIR than human reservoir infectiousness. This model and the input parameters from the four sites allow the potential impacts of various control measures on malaria transmission intensity to be tested under a range of endemic conditions. The model has potential applications for the development and implementation of transmission control measures and for public health education.

  18. Comparison of relevant parameters of multi-pixel sensors for tracker detectors after irradiation with high proton and neutron fluences

    International Nuclear Information System (INIS)

    Bergholz, Matthias

    2016-03-01

    The further increase of the luminosity of the Large Hadron Collider (LHC) at CERN requires new sensors for the tracking detector of the Compact Muon Soleniod (CMS) experiment. These sensors must be more radiation hard and of a finer granularity to lower the occupancy. In addition the new sensor modules must have a lower material budget and have to be self triggering. Sensor prototypes, the so called ''MPix''-sensors, produced on different materials were investigated for their radiation hardness. These sensors were fully characterized before and after irradiation. Of particular interest was the comparison of different bias methods, different materials and the influence of various geometries. The degeneration rate differs for the different sensor materials. The increase of the dark current of Float-Zone-Silicon is stronger for thicker sensors and less than for Magnetic-Czochralski-Silicon sensors. Both tested bias structures are damaged by the irradiation. The poly silicon resistance increases after irradiation by fifty percent. The Punch-Through-Structure is more effected by irradiation. The punch-through voltage increase by a factor of two. Due to the higher pixel current, the working point of the sensor is shifted to smaller differential resistances.

  19. Experimental verification of internal parameter in magnetically coupled boost used as PV optimizer in parallel association

    Science.gov (United States)

    Sawicki, Jean-Paul; Saint-Eve, Frédéric; Petit, Pierre; Aillerie, Michel

    2017-02-01

    This paper presents results of experiments aimed to verify a formula able to compute duty cycle in the case of pulse width modulation control for a DC-DC converter designed and realized in laboratory. This converter, called Magnetically Coupled Boost (MCB) is sized to step up only one photovoltaic module voltage to supply directly grid inverters. Duty cycle formula will be checked in a first time by identifying internal parameter, auto-transformer ratio, and in a second time by checking stability of operating point on the side of photovoltaic module. Thinking on nature of generator source and load connected to converter leads to imagine additional experiments to decide if auto-transformer ratio parameter could be used with fixed value or on the contrary with adaptive value. Effects of load variations on converter behavior or impact of possible shading on photovoltaic module are also mentioned, with aim to design robust control laws, in the case of parallel association, designed to compensate unwanted effects due to output voltage coupling.

  20. Assessment of Abdominal Fat Using High-field Magnetic Resonance Imaging and Anthropometric and Biochemical Parameters.

    Science.gov (United States)

    Al-Radaideh, Ali; Tayyem, Reema; Al-Fayomi, Kholoud; Nimer, Nisreen; Malkawi, Amer; Al-Zu Bi, Rana; Agraib, Lana; Athamneh, Imad; Hijjawi, Nawal

    2016-12-01

    To measure the abdominal subcutaneous fat (SF) and visceral fat (VF) volumes using high-field magnetic resonance imaging (MRI) and to investigate their association with selected anthropometric and biochemical parameters among obese and nonobese apparently healthy participants. A cross-sectional study was conducted by recruiting 167 healthy participants. Abdominal scans were acquired at 3T MRI, and the SF and VF were segmented and their volumes were calculated. Selected anthropometric and biochemical measurements were also determined. A significant difference (P abdominal fat volumes, leptin, resistin, adiponectin and waist circumference. Waist circumferences were measured by tape and MRI. Findings revealed that MRI-measured fat volumes were different between males and females and had a significant (P fat volumes were found to correlate moderately with interleukin-6 and weakly with cholesterol, serum triglyceride and low-density lipoprotein. Except for cholesterol, all measured biochemical variables and abdominal fat volumes in the current study were significantly associated with body mass index. All anthropometric and biochemical parameters showed weak-to-strong associations with the MRI-measured fat volumes. Abdominal fat distribution was different between males and females and their correlations with some lipid profiles were found to be sex dependent. These findings revealed that MRI can be used as an alternative tool for obesity assessment. Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

  1. Penalaan Parameter Superconducting Magnetic Energy Storage (SMES menggunakan Firefly Algorithm (FA pada Sistem Tenaga Listrik Multimesin

    Directory of Open Access Journals (Sweden)

    Herlambang Setiadi

    2014-03-01

    Full Text Available Energi listrik yang disuplai ke konsumen harus mempunyai stabilitas dan keandalan yang tinggi. Jika terjadi sebuah gangguan pada sistem tenaga listrik dapat mengakibatkan ketidakstabilan. Gangguan tersebut dapat berupa putus jaringan (transien maupun perubahan beban (dinamik. Perubahan beban yang terjadi secara tiba-tiba dan periodik tidak dapat direspon dengan baik oleh generator sehingga dapat mempengaruhi kestabilan dinamik sistem. Hal ini menyebabkan timbul osilasi frekuensi pada generator. Respon yang kurang baik dapat menimbulkan osilasi frekuensi dalam periode yang lama. Hal itu akan mengakibatkan pengurangan kekuatan transfer daya yang ada. Pada sistem tenaga listrik multimachine, semua mesin bekerja secara sinkron se­hingga generator harus beroperasi pada frekuensi yang sama. Untuk meredam osilasi frekuensi yang terjadi dibutuhkan kontroler tambahan yaitu Superconducting Magnetic Energy Storage (SMES. Agar mendapatkan koordinasi controler yang baik maka parameter pada SMES dioptimisasi dengan Firefly Algorithm (FA. Tugas Akhir ini mengajukan konsep penalaan parameter SMES menggunakan FA pada sistem tenaga listrik multimesin. Dengan diajukan metode diatas diharapkan permasalahan osilasi frekuensi akibat terdapat perubahan beban dapat diredam.

  2. Sextupole correction for a ring with large chromaticity and the influence of magnetic errors on its parameters

    International Nuclear Information System (INIS)

    Kamiya, Y.; Katoh, M.; Honjo, I.

    1987-01-01

    A future ring with a low emittance and large circumference, specifically dedicated to a synchrotron light source, will have a large chromaticity, so that it is important to employ a sophisticated sextupole correction as well as the design of linear lattice to obtain the stable beam. The authors tried a method of sextupole correction for a lattice with a large chromaticity and small dispersion function. In such a lattice the sextupole magnets are obliged to become large in strength to compensate the chromaticity. Then the nonlinear effects of the sextupole magnets will become more serious than their chromatic effects. Furthermore, a ring with strong quadrupole magnets to get a very small emittance and with strong sextupole magnets to compensate the generated chromaticity will be very sensitive to their magnetic errors. The authors also present simple formulae to evaluate the effects on the beam parameters. The details will appear in a KEK Report

  3. Relating Magnetic Parameters to Heavy Metal Concentrations and Environmental Factors at Formosa Mine Superfund Site, Douglas County, OR

    Science.gov (United States)

    Upton, T. L.

    2016-12-01

    Advances in the field of environmental magnetism have led to exciting new applications for this field. Magnetic minerals are ubiquitous in the environment and tend to have an affinity for heavy metals. Hence, it has been demonstrated that magnetic properties are often significantly related to concentrations of heavy metals and other pollutants. As a result, magnetic techniques have been used as proxy for determining hot spots of several types of pollution produced from a diversity of anthropogenic sources. Magnetic measurements are non-destructive and relatively inexpensive compared to geochemical analyses. The utility of environmental magnetic methods varies widely depending on biological, chemical and physical processes that create and transform soils and sediments. Applications in the direction of mapping heavy metals have been studied and shown to be quite useful in countries such as China and India but to date, little research has been done in the US. As such, there is need to expand the scope of research to a wider range of soil types and land uses, especially within the US. This study investigates the application of environmental magnetic techniques to mapping of heavy metal concentrations at the Formosa Mine Superfund Site, an abandoned mine about 25 miles southwest of Roseburg, OR. The soils and sediment at this site are derived from pyrite-rich bedrock which is weak in terms of magnetic susceptibility. Using hotspot analysis, correlation and cluster analyses, interactions between metals and magnetic parameters are investigated in relation to environmental factors such as proximity to seeps and adits. Preliminary results suggest significant correlation of magnetic susceptibility with certain heavy metals, signifying that magnetic methods may be useful in mapping heavy metal hotspots at this site. Further analysis examines the relation of various land use differences in magnetic signatures obtained throughout the Cow Creek watershed.

  4. Properties and parameters of the electron beam injected into the mirror magnetic trap of a plasma accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V. V., E-mail: temple18@mail.ru; Novitsky, A. A.; Vinnichenko, L. A.; Umnov, A. M.; Ndong, D. O. [Peoples’ Friendship University of Russia (Russian Federation)

    2016-03-15

    The parameters of the injector of an axial plasma beam injected into a plasma accelerator operating on the basis of gyroresonance acceleration of electrons in the reverse magnetic field are determined. The trapping of the beam electrons into the regime of gyroresonance acceleration is numerically simulated by the particle- in-cell method. The optimal time of axial injection of the beam into a magnetic mirror trap is determined. The beam parameters satisfying the condition of efficient particle trapping into the gyromagnetic autoresonance regime are found.

  5. Correlation between mass transfer coefficient kLa and relevant operating parameters in cylindrical disposable shaken bioreactors on a bench-to-pilot scale.

    Science.gov (United States)

    Klöckner, Wolf; Gacem, Riad; Anderlei, Tibor; Raven, Nicole; Schillberg, Stefan; Lattermann, Clemens; Büchs, Jochen

    2013-12-02

    Among disposable bioreactor systems, cylindrical orbitally shaken bioreactors show important advantages. They provide a well-defined hydrodynamic flow combined with excellent mixing and oxygen transfer for mammalian and plant cell cultivations. Since there is no known universal correlation between the volumetric mass transfer coefficient for oxygen kLa and relevant operating parameters in such bioreactor systems, the aim of this current study is to experimentally determine a universal kLa correlation. A Respiration Activity Monitoring System (RAMOS) was used to measure kLa values in cylindrical disposable shaken bioreactors and Buckingham's π-Theorem was applied to define a dimensionless equation for kLa. In this way, a scale- and volume-independent kLa correlation was developed and validated in bioreactors with volumes from 2 L to 200 L. The final correlation was used to calculate cultivation parameters at different scales to allow a sufficient oxygen supply of tobacco BY-2 cell suspension cultures. The resulting equation can be universally applied to calculate the mass transfer coefficient for any of seven relevant cultivation parameters such as the reactor diameter, the shaking frequency, the filling volume, the viscosity, the oxygen diffusion coefficient, the gravitational acceleration or the shaking diameter within an accuracy range of +/- 30%. To our knowledge, this is the first kLa correlation that has been defined and validated for the cited bioreactor system on a bench-to-pilot scale.

  6. Characterization of the radiation resistance of ITER-relevant and innovative fiber composites for the ITER magnet system

    International Nuclear Information System (INIS)

    Bittner-Rohrhofer, K.

    2003-06-01

    The application of glass-fiber reinforced composites for the insulation of the superconducting magnet coils of the ITER (International Thermonuclear Experimental Reactor ) fusion device requires high material performance. The mechanical integrity of the insulation is influenced by the neutron- and g-environment and by the high mechanical stresses of the magnet system over the entire plant lifetime of 20 years. Materials suggested as insulation have to be investigated in extensive test programs with respect to the present ITER design criteria. In particular, the ultimate tensile strength as well as the interlaminar shear behavior will change under static and dynamic load (tension-tension fatigue) at 77 K after irradiation to the ITER design fluence level of 1x1022 m-2 (E620.1 MeV). Therefore, a frequency of 10 Hz and a ratio of 0.1 were chosen, in order to simulate the pulsed TOKAMAK-operation as closely as possible. Furthermore, the fatigue behavior of the material is investigated over more than 3x104 cycles, which is the ITER- relevant design fatigue limit. Basically, these insulation systems are based on combined glass-fiber/Kapton tapes, which are impregnated with di-functional DGEBA epoxy resins. Several mechanical investigations showed that the radiation resistance of these organic resins is dramatically affected by radiation at a neutron fluence of 1x1022 m-2 (E620.1 MeV). Moreover, the material strength after irradiation is strongly influenced by these factors: the winding direction of the tapes, the quality of fabrication and the drastic delamination process of the whole compound. Furthermore, the radiation induced damage of adhesives applied for supporting the interfacial bonding between the glass-fiber tape and Kapton has an adverse effect on the material performance. In addition, the poor interlaminar shear behavior does not fulfil the requirements of ITER. These test-results motivated for the development of innovative resin systems with higher stability

  7. Effect of Synthesis Parameters on the Structure and Magnetic Properties of Magnetic Manganese Ferrite/Silver Composite Nanoparticles Synthesized by Wet Chemistry Method

    DEFF Research Database (Denmark)

    Huy, L.T.; Tam, L.T.; Phan, V.N.

    2016-01-01

    In the present work, magnetic manganese ferrite/silver (MnFe2O4-Ag) composite nanoparticles were synthesized by wet chemistry method. This synthesis process consists of two steps: first, the seed of manganese ferrite nanoparticles (MnFe2O4 NPs) was prepared by a coprecipitationmethod; second......, growth of silver nanoparticles (AgNPs) on the MnFe2O4 seed by modified photochemical reaction. We have conducted systematically the effects of synthesis parameters such as pH value, synthesis time, precursor salts concentration, mass ratio and stabilizing agents on the structure and magnetic properties......-prepared MnFe2O4-Ag magnetic nanocomposites display excellent properties of high crystallinity, long-term aggregation stability in aqueous medium, large saturation magnetization in the range of 15-20 emu/g, and small sizes of Ag-NPs similar to 20 nm. These exhibited properties made the MnFe2O4-Ag...

  8. Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping

    Science.gov (United States)

    Peterchev, Angel V.; DʼOstilio, Kevin; Rothwell, John C.; Murphy, David L.

    2014-10-01

    Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with a lower voltage rating than prior cTMS devices. Main results. cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The near-zero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (\\lt 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in ten healthy volunteers. Significance. The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool.

  9. Nuclear magnetism of liquid 3He: new determination of the Landau parameter F0a

    International Nuclear Information System (INIS)

    Goudon, V.

    2006-10-01

    He 3 is a liquid Fermi model, isotropic, with an attainable Fermi temperature and the interaction between atoms can be controlled by changing the pressure of the liquid. In this document, we present accurate NMR measurements of the nuclear magnetic susceptibility of liquid He 3 as a function of temperature and pressure. The emphasis has been placed on reliable thermometry and on He 3 pressure measurements directly in the cell to increase the measuring range until solidification, and an accurate characterization of the NMR spectrometer. Our measurements give an effective Fermi temperature 5% lower than former results. The Landau parameter F 0 a depends on the effective mass, which is determined by specific heat measurements, and consequently on the temperature scale. The re-analysis of the specific heat measurements with the PLTS-2000 temperature scale yields an effective mass increase of 4.5%. In this document, F 0 a is determined for 2 temperature scales (PLTS-2000 and Greywall). Contrarily to former measurements, the F 0 a density dependence does not show any saturation at high pressures. (author)

  10. THE EFFECTS OF SPATIAL SMOOTHING ON SOLAR MAGNETIC HELICITY PARAMETERS AND THE HEMISPHERIC HELICITY SIGN RULE

    Energy Technology Data Exchange (ETDEWEB)

    Ocker, Stella Koch [Department of Physics, Oberlin College, Oberlin, OH 44074 (United States); Petrie, Gordon, E-mail: socker@oberlin.edu, E-mail: gpetrie@nso.edu [National Solar Observatory, Boulder, CO 80303 (United States)

    2016-12-01

    The hemispheric preference for negative/positive helicity to occur in the northern/southern solar hemisphere provides clues to the causes of twisted, flaring magnetic fields. Previous studies on the hemisphere rule may have been affected by seeing from atmospheric turbulence. Using Hinode /SOT-SP data spanning 2006–2013, we studied the effects of two spatial smoothing tests that imitate atmospheric seeing: noise reduction by ignoring pixel values weaker than the estimated noise threshold, and Gaussian spatial smoothing. We studied in detail the effects of atmospheric seeing on the helicity distributions across various field strengths for active regions (ARs) NOAA 11158 and NOAA 11243, in addition to studying the average helicities of 179 ARs with and without smoothing. We found that, rather than changing trends in the helicity distributions, spatial smoothing modified existing trends by reducing random noise and by regressing outliers toward the mean, or removing them altogether. Furthermore, the average helicity parameter values of the 179 ARs did not conform to the hemisphere rule: independent of smoothing, the weak-vertical-field values tended to be negative in both hemispheres, and the strong-vertical-field values tended to be positive, especially in the south. We conclude that spatial smoothing does not significantly affect the overall statistics for space-based data, and thus seeing from atmospheric turbulence seems not to have significantly affected previous studies’ ground-based results on the hemisphere rule.

  11. Effect of the template-assisted electrodeposition parameters on the structure and magnetic properties of Co nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kac, Malgorzata, E-mail: malgorzata.kac@ifj.edu.pl [Institute of Nuclear Physics Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Zarzycki, Arkadiusz [Institute of Nuclear Physics Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland); Kac, Slawomir [AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Kopec, Marek; Perzanowski, Marcin; Dutkiewicz, Erazm M.; Suchanek, Katarzyna; Maximenko, Alexey; Marszalek, Marta [Institute of Nuclear Physics Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Krakow (Poland)

    2016-09-15

    Highlights: • Magnetic properties of Co nanowires in polycarbonate membranes were studied. • Electrodeposition stages were illustrated by SEM images. • Electrolyte and membrane parameters were optimized for Co nanowire fabrication. • Low temperature and potential favored nanowires with high coercivity and squareness. - Abstract: We studied the magnetic properties of Co nanowires electrodeposited in polycarbonate membranes as a function of the electrodeposition and template parameters. We showed the response of the current as a function of time, for nanowires prepared in various conditions. X-ray diffraction measurements indicate that nanowires have polycrystalline hcp structure with small addition of fcc phase. Magnetic properties analyzed by SQUID measurements suggest that easy axis of magnetization follows the nanowire axis with coercivity increasing with a decrease of nanowire diameter and length. The largest coercivity, equal to 850 Oe, was obtained for nanowires with the diameter of 30 nm and the length of 1.5 μm. We find the coercivity to be insensitive to pH value. Low electrodeposition temperature, low cathodic potential, and medium pH are the synthesis parameters most beneficial for large coercivity and/or magnetic anisotropy with easy axis along nanowires.

  12. The prognostic value of cortical magnetic stimulation in acute middle cerebral artery infarction compared to other parameters

    NARCIS (Netherlands)

    Timmerhuis, Th.P.J.; Hageman, G.; Oosterloo, Sebe J.; Rozeboom, A.R.

    1996-01-01

    The prognostic value of magnetic evoked potentials (MEP), somatosensory evoked potentials (SSEP), age and radiological parameters was determined in 50 patients with acute middle cerebral artery infarction. We performed MEP and SSEP within 4 days and after 6 weeks and 3 months of the infarction and

  13. Low field magnetic resonance imaging of the lumbar spine: Reliability of qualitative evaluation of disc and muscle parameters

    DEFF Research Database (Denmark)

    Sørensen, Joan Solgaard; Kjaer, Per; Jensen, Tue Secher

    2006-01-01

    PURPOSE: To determine the intra- and interobserver reliability in grading disc and muscle parameters using low-field magnetic resonance imaging (MRI). MATERIAL AND METHODS: MRI scans of 100 subjects representative of the general population were evaluated blindly by two radiologists. Criteria......: Convincing reliability was found in the evaluation of disc- and muscle-related MRI variables....

  14. Relevance of southward magnetic fields in the neutral sheet to anisotropic distribution of energetic electrons and substorm activity

    International Nuclear Information System (INIS)

    Lui, A.T.Y.; Meng, C.

    1979-01-01

    The implications of southward magnetic fields at the magnetotail neutral sheet to the development of streaming anisotropy of energetic electrons and magnetospheric substorm activity are examined. Magnetic field and energetic particle measurements from the Imp 6 spacecraft, the AE index, and global auroral images from DMSP spacecraft are utilized in this study. Criteria are developed to identify events of southward magnetic fields at the neutral sheet which imply the presence of X-type magnetic neutral lines. Several features of the observations suggest that the southward magnetic fields and the implied X-type neutral lines are associated with magnetic bubbles in the neutral sheet region. It is found that the signatures of magnetic bubbles are sometimes detected in association with tailward streaming and flux enhancement of energetic electrons (47 keV< E<350keV). A cigar-shaped anisotropy in the energetic electron distribution is frequently but not always observed before the onset of tailward streaming of energetic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggestic electrons. The tailward streaming is magnetic field-aligned and occurs in the form of bursts, suggesting that the generating process is activated somewhat quasi-periodically and is not in a steady state. Signatures of magnetic bubbles are also detected without any substantial enhancement or detectable tailward streaming of energetic electrons. By comparing Imp 6 observations with the AW index and global auroral images from DMSP spacecraft. It is found that signatures of magnetic bubbles in the neutral sheet are observed during substorms as well as during quiet geomagnetic conditions, indicating that magnetic bubbles are intrinsic features of the neutral sheet in the magnetotail regardless of substorm activity

  15. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

      The magnet was operated without any problem until the end of the LHC run in February 2013, apart from a CERN-wide power glitch on 10 January 2013 that affected the CMS refrigerator, causing a ramp down to 2 T in order to reconnect the coldbox. Another CERN-wide power glitch on 15 January 2013 didn’t affect the magnet subsystems, the cryoplant or the power converter. At the end of the magnet run, the reconnection of the coldbox at 2.5 T was tested. The process will be updated, in particular the parameters of some PID valve controllers. The helium flow of the current leads was reduced but only for a few seconds. The exercise will be repeated with the revised parameters to validate the automatic reconnection process of the coldbox. During LS1, the water-cooling services will be reduced and many interventions are planned on the electrical services. Therefore, the magnet cryogenics and subsystems will be stopped for several months, and the magnet cannot be kept cold. In order to avoid unc...

  16. Micro-scale grain-size analysis and magnetic properties of coal-fired power plant fly ash and its relevance for environmental magnetic pollution studies

    Energy Technology Data Exchange (ETDEWEB)

    Blaha, U.; Sapkota, B.; Appel, E.; Stanjek, H.; Rosler, W. [University of Tubingen, Tubingen (Germany). Inst. of Geoscience

    2008-11-15

    Two fly ash samples from a black coal-fired power plant (Bexbach, Germany) were investigated for their magnetic properties, particle structure, grain-size distribution and chemical composition. Grain-size distribution was determined on bulk samples and on magnetic extracts. Magnetic susceptibility of different grain-size fractions was analyzed with respect to the according amount of fractions, high- and low-temperature dependence of magnetic susceptibility and thermal demagnetization of IRM identified magnetite and hematite as magnetic phases. Magnetic spherules were quantitatively extracted from bulk fly ash samples and examined using SEM/EDX analysis. Particle morphology and grain-size analysis on the magnetically extracted material were studied. Individual spherule types were identified and internal structures of selected polished particles were investigated by SEM and EDX analyses. Main element contents of the internal structures which consist of 'magnetite' crystals and 'glassy' matrix were systematically determined and statistically assessed. The chemical data of the micro-scale structures in the magnetic spherules were compared with XRF data from bulk material, revealing the relative element distribution in composed magnetic spherules. Comparison of the bulk sample grain-size (0.5-300 {mu}m) and grain-size spectra from magnetic extracts (1-186.5 {mu}m) shows that strongly magnetic particles mainly occur in the fine fractions of < 63 {mu}m. This study comprises a comprehensive characterization of coal-fired power plant fly ash, using magnetic, chemical, and microscopic methods. The results can serve as reference data for a variety of environmental magnetic studies.

  17. Multiple scattering of electromagnetic waves in disordered magnetic media localization parameter, energy transport velocity and diffusion constant

    CERN Document Server

    Pinheiro, F A; Martínez, A S

    2001-01-01

    We review some of our recent results concerning the single and multiple electromagnetic scattering by magnetic spherical particles. For a single electromagnetic scattering we show that the magnetic contribution alters, when compared to nonmagnetic scattering, the behavior of the cross sections and mean cosine of the scattering angle (cos omega). For ferromagnetic particles, resonances may occur even in the small-particle limit when the particle radius is much smaller than the wavelength. The resonances increase the cross sections while (cos omega) is diminished , and even may become negative. Several quantities such the Ioffe-Regel parameter for localization are calculated for the multiple scattering regime. We show that magnetic scattering favors the observation of localization of electromagnetic waves in three dimensions. Further, this is also verified for dynamical experiments, where we show that the diffusion constant can be very small. Since the magnetic permeability of the scatterers can vary significan...

  18. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

  19. LARGE SCALE DISTRIBUTED PARAMETER MODEL OF MAIN MAGNET SYSTEM AND FREQUENCY DECOMPOSITION ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    ZHANG,W.; MARNERIS, I.; SANDBERG, J.

    2007-06-25

    Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, they become a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large-scale network. Its equivalent polynomial form has several hundred degrees. Analysis of this high order circuit and simulation of the response of any or all components is often computationally infeasible. We present methods to use frequency decomposition approach to effectively simulate and analyze magnet configuration and power supply topologies.

  20. ELECTROMAGNETIC SAFETY OF ELECTRIC TRANSPORT SYSTEMS: MAIN SOURCES AND PARAMETERS OF MAGNETIC FIELDS

    Directory of Open Access Journals (Sweden)

    N. G. Ptitsyna

    2013-03-01

    Full Text Available Magnetic fields produced by electric drive vehicles may break electromagnetic safety. For electromagnetic safety and electromagnetic compatibility knowledge about characteristics and sources of magnetic fields in the electric transport is necessary. The article deals with analysis of available data about magnetic fields in electric cars and comparison with results of our measurements carried out in the other types of electrified transport systems.

  1. Magnetic parameters of forest top soils in Krušné hory region

    Czech Academy of Sciences Publication Activity Database

    Kapička, Aleš; Petrovský, Eduard; Fialová, Hana; Podrázský, V.; Křížek, P.

    2008-01-01

    Roč. 38, Special issue (2008), s. 54-55 ISSN 1335-2806. [Paleo, Rock and Environmental Magnetism. Castle Meeting /11./. 22.06.2008-28.06.2008, Bojnice] R&D Projects: GA ČR GA205/07/0941 Institutional research plan: CEZ:AV0Z30120515 Keywords : magnetic properties of soils * mapping of pollution * Krušné hory region Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  2. TH-CD-BRA-07: MRI-Linac Dosimetry: Parameters That Change in a Magnetic Field

    International Nuclear Information System (INIS)

    O’Brien, D. J.; Sawakuchi, G. O.

    2016-01-01

    Purpose: In MRI-linac integrated systems, the presence of the magnetic (B-)field has a large impact of the dose-distribution and the dose-responses of detectors; yet established protocols and previous experience may lead to assumptions about the commissioning process that are no longer valid. This study quantifies parameters that change when performing dosimetry with an MRI-linac including beam quality specifiers and the effective-point-of-measurement (EPOM) of ionization chambers. Methods: We used the Geant4 Monte Carlo code for this work with physics parameters that pass the Fano cavity test to within 0.1% for the simulated conditions with and without a 1.5 T B-field. A point source model with the energy distribution of an MRI-linac beam was used with and without the B-field to calculate the beam quality specifiers %dd(10)× and TPR 20 10 , the variation of chamber response with orientation and the how the B-field affects the EPOM of ionization chambers by comparing depth-dose curves calculated in water to those generated by a model PTW30013 Farmer chamber. Results: The %dd(10)× changes by over 2% in the presence of the B-field while the TPR 20 10 is unaffected. Ionization chamber dose-response is known to depend on the orientation w.r.t. the B-field, but two alternative perpendicular orientations (anti-parallel to each other) also differ in dose-response by over 1%. The B-field shifts the EPOM downstream (closer to the chamber center) but it is also shifted laterally by 0.27 times the chamber’s cavity radius. Conclusion: The EPOM is affected by the B-field and it even shifts laterally. The relationship between %dd(10)× and the Spencer-Attix stopping powers is also changed. Care must be taken when using chambers perpendicular to the field as the dose-response changes depending on which perpendicular orientation is used. All of these effects must be considered when performing dosimetry in B-fields and should be accounted for in future dosimetry protocols. This

  3. TH-CD-BRA-07: MRI-Linac Dosimetry: Parameters That Change in a Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    O’Brien, D. J.; Sawakuchi, G. O. [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: In MRI-linac integrated systems, the presence of the magnetic (B-)field has a large impact of the dose-distribution and the dose-responses of detectors; yet established protocols and previous experience may lead to assumptions about the commissioning process that are no longer valid. This study quantifies parameters that change when performing dosimetry with an MRI-linac including beam quality specifiers and the effective-point-of-measurement (EPOM) of ionization chambers. Methods: We used the Geant4 Monte Carlo code for this work with physics parameters that pass the Fano cavity test to within 0.1% for the simulated conditions with and without a 1.5 T B-field. A point source model with the energy distribution of an MRI-linac beam was used with and without the B-field to calculate the beam quality specifiers %dd(10)× and TPR{sup 20}{sub 10}, the variation of chamber response with orientation and the how the B-field affects the EPOM of ionization chambers by comparing depth-dose curves calculated in water to those generated by a model PTW30013 Farmer chamber. Results: The %dd(10)× changes by over 2% in the presence of the B-field while the TPR{sup 20}{sub 10} is unaffected. Ionization chamber dose-response is known to depend on the orientation w.r.t. the B-field, but two alternative perpendicular orientations (anti-parallel to each other) also differ in dose-response by over 1%. The B-field shifts the EPOM downstream (closer to the chamber center) but it is also shifted laterally by 0.27 times the chamber’s cavity radius. Conclusion: The EPOM is affected by the B-field and it even shifts laterally. The relationship between %dd(10)× and the Spencer-Attix stopping powers is also changed. Care must be taken when using chambers perpendicular to the field as the dose-response changes depending on which perpendicular orientation is used. All of these effects must be considered when performing dosimetry in B-fields and should be accounted for in future

  4. Bimonthly assessment of magnetization transfer magnetic resonance imaging parameters in multiple sclerosis: a 14-month, multicentre, follow-up study

    NARCIS (Netherlands)

    Mesaros, S.; Rocca, M.A.; Sormani, M.P.; Valsasina, P.; Markowitz, C.; De Stefano, N.; Montalban, X.; Barkhof, F.; Ranjeva, J.P.; Sailer, M.; Kappos, L.; Comi, G.; Filippi, M.

    2010-01-01

    This study was performed to assess the temporal evolution of damage within lesions and the normal-appearing white matter, measured using frequent magnetization transfer (MT) MRI, in relapsing-remitting multiple sclerosis (RRMS). The relationship of MT ratio (MTR) changes with measures of lesion

  5. Assessment of Retained Austenite in AISI D2 Tool Steel Using Magnetic Hysteresis and Barkhausen Noise Parameters

    Science.gov (United States)

    Kahrobaee, Saeed; Kashefi, Mehrdad

    2015-03-01

    Inaccurate heat treatment process could result in excessive amount of retained austenite, which degrades the mechanical properties, like strength, wear resistance, and hardness of cold work tool steel parts. Thus, to control the mechanical properties, quantitative measurement of the retained austenite is a critical step in optimizing the heat-treating parameters. X-ray diffraction method is the most frequently used technique for this purpose. This technique is, however, destructive and time consuming. Furthermore, it is not applicable to 100% quality inspection of industrial parts. In the present paper, the influence of austenitizing temperature on the retained austenite content and hardness of AISI D2 tool steel has been studied. Additionally, nondestructive magnetic hysteresis parameters of the samples including coercivity, magnetic saturation, and maximum differential permeability as well as their magnetic Barkhausen noise features (RMS peak voltage and peak position) have been investigated. The results revealed direct relations between magnetic saturation, differential permeability, and MBN peak amplitude with increasing austenitizing temperature due to the retained austenite formation. Besides, both parameters of coercivity and peak position had an inverse correlation with the retained austenite fraction.

  6. Identification of Plasma Parameters and Optimization of Magnetic Sensors in the Superconducting Steady-State Tokamak-1 Using Neural Networks

    International Nuclear Information System (INIS)

    Sengupta, A.; Ranjan, P.

    2001-01-01

    In this paper, we examine the possibility of using a multilayered feedforward neural network to extract tokamak plasma parameters from magnetic measurements as an improvement over the traditional methodology of function parametrization. It is also used to optimize the number and locations of the magnetic diagnostics designed for the tokamak. This work has been undertaken with the specific purpose of application of the neural network technique to the newly designed (and currently under fabrication) Superconducting Steady-State Tokamak-1 (SST-1). The magnetic measurements will be utilized to achieve real-time control of plasma shape, position, and some global profiles. A trained neural network is tested, and the results of parameter identification are compared with function parametrization. Both techniques appear well suited for the purpose, but a definite improvement with neural networks is observed. Although simulated measurements are used in this work, confidence regarding the network performance with actual experimental data is ensured by testing the network's noise tolerance with Gaussian noise of up to 10%. Finally, three possible methods of ranking the diagnostics in decreasing order of importance are suggested, and the neural network is used to optimize the number and locations of the magnetic sensors designed for SST-1. The results from the three methods are compared with one another and also with function parametrization. Magnetic probes within the plasma-facing side of the outboard limiter have been ranked high. Function parametrization and one of the neural network methods show a distinct tendency to favor the probes in the remote regions of the vacuum vessel, proving the importance of redundancy. Fault tolerance of the optimized network is tested. The results obtained should, in the long run, help in the decision regarding the final effective set of magnetic diagnostics to be used in SST-1 for reconstruction of the control parameters

  7. The order parameter equations of superfluid Fermi-liquid with spin-triplet pairing near Tc in magnetic field

    International Nuclear Information System (INIS)

    Tarasov, A.N.

    1995-01-01

    The article is devoted to description of equilibrium properties of superfluid phases of 3 He in magnetic field at temperatures near the normal-superfluid point T c . The Landau Fermi-liquid (F-L) approach generalized to superfluid Fermi-liquids (SFLs) is used. Equations for the order parameter paramagnetic SFL with spin-triplet pairing in static and uniform (DC) moderately strong magnetic field are derived without taking into account strong-coupling (SC) effects. An integro-differential equation is deduced for the order parameter in the general case of spin-triplet pairing (spin of a pair is s = 1, orbital moment l of a pair is any odd number). It is valid in the approximation of small space inhomogeneities of the SFL for external DC magnetic field at temperatures near T c . In the case of spin-triplet p-wave pairing a Ginzburg-Landau (GL) equation is derived for the order parameter A αj (complex 3 x 3 matrix). Corrections to the coefficients in the GL eq. are resulted from taking into account the influence of moderately strong DC magnetic field and spin-exchange F-L interaction by the theory of permutations. In such fields these corrections can be of the same order of magnitude as the so-called > SC corrections to the GL eq. (or even exceed them) and are much higher than the particle-hole asymmetric contribution. The above corrections are connected with deformation of the order parameter in moderate magnetic fields and are of interest at description of 3 He - B at low pressures

  8. Utilizing of magnetic parameters for evaluation of soil erosion rates on two different agricultural sites

    Science.gov (United States)

    Kapicka, A.; Grison, H.; Petrovsky, E.; Jaksik, O.; Kodesova, R.

    2015-12-01

    Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points at Brumovice and 65 at Vidim locality. Mass specific magnetic susceptibility χ and its frequency dependence χFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin in topsoil horizons. The lowest magnetic susceptibility was obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). Soil profiles unaffected by erosion were investigated in detail. The vertical distribution of magnetic susceptibility along these "virgin" profiles was measured in laboratory on samples collected with 2-cm spacing. The differences between the distribution of susceptibility in the undisturbed soil profiles and the magnetic signal after uniform mixing of the soil material as a result of erosion and tillage are fundamental for the estimation of soil loss in the studied test fields. Maximum cumulative soil erosion depth in Brumovice and Vidim is around 100 cm and 50 cm respectively. The magnetic method is suitable for mapping at the chernozem localities and measurement of soil magnetic susceptibility is in this case useful and fast technique for quantitative estimation of soil loss caused by erosion. However, it is less suitable (due to lower magnetic differentiation with depth) in areas with luvisol as dominant soil unit. Acknowledgement: This study was supported by NAZV Agency of the Ministry of Agriculture of the Czech Republic through grant No QJ1230319.

  9. Superconducting high current magnetic Circuit: Design and Parameter Estimation of a Simulation Model

    CERN Document Server

    Kiefer, Alexander; Reich, Werner Dr

    The Large Hadron Collider (LHC) utilizes superconducting main dipole magnets that bend the trajectory of the particle beams. In order to adjust the not completely homogeneous magnetic feld of the main dipole magnets, amongst others, sextupole correctcorrector magnets are used. In one of the 16 corrector magnet circuits placed in the LHC, 154 of these sextupole corrector magnets (MCS) are connected in series. This circuit extends on a 3.35 km tunnel section of the LHC. In 2015, at one of the 16 circuits a fault was detected. The simulation of this circuit is helpful for fnding the fault by applying alternating current at different frequencies. Within this Thesis a PSpice model for the simulation of the superconducting corrector magnet circuit was designed. The physical properties of the circuit and its elements were analyzed and implemented. For the magnets and bus-bars, sub-circuits were created which reflect the parasitic effects of electrodynamics and electrostats. The inductance values and capacitance valu...

  10. Effect of processing parameters on the magnetic properties and microstructures of molybdenum permalloy compacts made by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhangming; Xu, Wei; Guo, Ting; Jiang, Yinzhu; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

    2014-05-01

    Highlights: • Effect of processing parameters on the properties of MP powder cores was studied. • Effective magnetic permeability was enhanced from 45 to 160 after annealing. • A core loss of 780 mw/cm{sup 3} (100 kHz, 100 mT) was obtained. - Abstract: Effects of compaction and annealing process on the magnetic properties and microstructures of molybdenum permalloy (MP) powder cores have been investigated. MP compacts, with density as high as 92% of the theoretical value, were obtained under 1800 MPa compaction pressure. The MP powder cores show an enhanced effective magnetic permeability of 160 after post-annealing at 690 °C, which is attributed to the relief of internal stress rather than the phase transformation evidenced by the XRD analysis. However, higher annealing temperature destroys the insulating layer, resulting in the drop of the electrical resistivity, the effective magnetic permeability as well as the frequency stability. The results show that the samples compacted at 1800 MPa and annealed at 690 °C exhibit excellent magnetic properties, with core loss of 780 mw/cm{sup 3} (100 kHz, 100 mT) and effective magnetic permeability of 160 whose frequency stability is up to 1 MHz.

  11. Evaluation of Parameters Affecting Magnetic Abrasive Finishing on Concave Freeform Surface of Al Alloy via RSM Method

    Directory of Open Access Journals (Sweden)

    Mehrdad Vahdati

    2016-01-01

    Full Text Available The attempts of researchers in industries to obtain accurate and high quality surfaces led to the invention of new methods of finishing. Magnetic abrasive finishing (MAF is a relatively new type of finishing in which the magnetic field is used to control the abrasive tools. Applications such as the surface of molds are ones of the parts which require very high surface smoothness. Usually this type of parts has freeform surface. In this study, the effect of magnetic abrasive process parameters on freeform surfaces of parts made of aluminum is examined. This method is obtained through combination of magnetic abrasive process and Control Numerical Computer (CNC. The use of simple hemisphere for installation on the flat area of the magnets as well as magnets’ spark in curve form is a measure done during testing the experiments. The design of experiments is based on response surface methodology. The gap, the rotational speed of the spindle, and the feed rate are found influential and regression equations governing the process are also determined. The impact of intensity of the magnetic field is obtained using the finite element software of Maxwell. Results show that in concave areas of the surface, generally speaking, the surface roughness decreases to 0.2 μm from its initial 1.3 μm roughness. However, in some points the lowest surface roughness of 0.08 μm was measured.

  12. Effect of nonlinear void reactivity on bifurcation characteristics of a lumped-parameter model of a BWR: A study relevant to RBMK

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Dinkar, E-mail: dinkar@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology Kanpur, Kanpur 208 016 (India); Kalra, Manjeet Singh, E-mail: drmanjeet.singh@dituniversity.edu.in [DIT University, Dehradun 248 009 (India); Wahi, Pankaj, E-mail: wahi@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2017-04-15

    Highlights: • A simplified model with nonlinear void reactivity feedback is studied. • Method of multiple scales for nonlinear analysis and oscillation characteristics. • Second order void reactivity dominates in determining system dynamics. • Opposing signs of linear and quadratic void reactivity enhances global safety. - Abstract: In the present work, the effect of nonlinear void reactivity on the dynamics of a simplified lumped-parameter model for a boiling water reactor (BWR) is investigated. A mathematical model of five differential equations comprising of neutronics and thermal-hydraulics encompassing the nonlinearities associated with both the reactivity feedbacks and the heat transfer process has been used. To this end, we have considered parameters relevant to RBMK for which the void reactivity is known to be nonlinear. A nonlinear analysis of the model exploiting the method of multiple time scales (MMTS) predicts the occurrence of the two types of Hopf bifurcation, namely subcritical and supercritical, leading to the evolution of limit cycles for a range of parameters. Numerical simulations have been performed to verify the analytical results obtained by MMTS. The study shows that the nonlinear reactivity has a significant influence on the system dynamics. A parametric study with varying nominal reactor power and operating conditions in coolant channel has also been performed which shows the effect of change in concerned parameter on the boundary between regions of sub- and super-critical Hopf bifurcations in the space constituted by the two coefficients of reactivities viz. the void and the Doppler coefficient of reactivities. In particular, we find that introduction of a negative quadratic term in the void reactivity feedback significantly increases the supercritical region and dominates in determining the system dynamics.

  13. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The CMS magnet has been running steadily and smoothly since the summer, with no detected flaw. The magnet instrumentation is entirely operational and all the parameters are at their nominal values. Three power cuts on the electrical network affected the magnet run in the past five months, with no impact on the data-taking as the accelerator was also affected at the same time. On 22nd June, a thunderstorm caused a power glitch on the service electrical network. The primary water cooling at Point 5 was stopped. Despite a quick restart of the water cooling, the inlet temperature of the demineralised water on the busbar cooling circuit increased by 5 °C, up to 23.3 °C. It was kept below the threshold of 27 °C by switching off other cooling circuits to avoid the trigger of a slow dump of the magnet. The cold box of the cryogenics also stopped. Part of the spare liquid helium volume was used to maintain the cooling of the magnet at 4.5 K. The operators of the cryogenics quickly restarted ...

  14. MATLAB-based program for optimization of quantum cascade laser active region parameters and calculation of output characteristics in magnetic field

    Science.gov (United States)

    Smiljanić, J.; Žeželj, M.; Milanović, V.; Radovanović, J.; Stanković, I.

    2014-03-01

    A strong magnetic field applied along the growth direction of a quantum cascade laser (QCL) active region gives rise to a spectrum of discrete energy states, the Landau levels. By combining quantum engineering of a QCL with a static magnetic field, we can selectively inhibit/enhance non-radiative electron relaxation process between the relevant Landau levels of a triple quantum well and realize a tunable surface emitting device. An efficient numerical algorithm implementation is presented of optimization of GaAs/AlGaAs QCL region parameters and calculation of output properties in the magnetic field. Both theoretical analysis and MATLAB implementation are given for LO-phonon and interface roughness scattering mechanisms on the operation of QCL. At elevated temperatures, electrons in the relevant laser states absorb/emit more LO-phonons which results in reduction of the optical gain. The decrease in the optical gain is moderated by the occurrence of interface roughness scattering, which remains unchanged with increasing temperature. Using the calculated scattering rates as input data, rate equations can be solved and population inversion and the optical gain obtained. Incorporation of the interface roughness scattering mechanism into the model did not create new resonant peaks of the optical gain. However, it resulted in shifting the existing peaks positions and overall reduction of the optical gain. Catalogue identifier: AERL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERL_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 37763 No. of bytes in distributed program, including test data, etc.: 2757956 Distribution format: tar.gz Programming language: MATLAB. Computer: Any capable of running MATLAB version R2010a or higher. Operating system: Any platform

  15. Plasma parameters, fluctuations and kinetics in a magnetic field line reconnection experiment

    International Nuclear Information System (INIS)

    Wild, N.C. Jr.

    1983-01-01

    The processes associated with reconnecting magnetic field lines have been studied in a large experimental laboratory plasma. Detailed time- and space-resolved probe measurements of the plasma density, temperature, potential and electric and magnetic fields are discussed. Plasma currents are seen to modify the vacuum magnetic field topology. A flat neutral sheet develops along the separatrix where magnetic flux is transferred from regions of private to common flux. Forced tearing and magnetic island formation are also observed. Rapid electron heating, density and temperature nonuniformities and plasma potential gradients are all observed. The pressure is found to peak at the two edges of the neutral sheet. The dissipation E.J is determined and analyzed in terms of particle heating and fluid acceleration. A consistent, detailed picture of the energy flow via Poynting's theorem is also described. Significant temporal fluctuations in the magnetic fields and electron velocity distribution are measured and seen to give rise to anomalously high values for the plasma resistivity, the ion viscosity and the cross-field thermal conductivity. Electron temperature fluctuations, double layers associated with partial current disruptions, and whistler wave magnetic turbulence have all been identified and studied during the course of the reconnection event

  16. Magnetic Grüneisen parameter and magnetocaloric properties of a coupled spin–electron double-tetrahedral chain

    International Nuclear Information System (INIS)

    Gálisová, Lucia; Strečka, Jozef

    2015-01-01

    Magnetocaloric effect in a double-tetrahedral chain, in which nodal lattice sites occupied by the localized Ising spins regularly alternate with three equivalent lattice sites available for mobile electrons, is exactly investigated by considering the one-third electron filling and the ferromagnetic Ising exchange interaction between the mobile electrons and their nearest Ising neighbours. The entropy and the magnetic Grüneisen parameter, which closely relate to the magnetocaloric effect, are exactly calculated in order to investigate the relation between the ground-state degeneracy and the cooling efficiency of the hybrid spin–electron system during the adiabatic demagnetization. - Highlights: • A double-tetrahedral chain of mobile electrons and localized Ising spins is studied. • Magnetic Grüneisen parameter for the system is exactly derived. • Macroscopically degenerate phases FRU and FM constitute the ground state. • MCE is three times higher nearby FRU–FM transition than in FRU phase at small fields

  17. Discovery of a new phase with magnetic short range correlations and its possible relevance for the hidden order in URu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sykora, Steffen [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Becker, Klaus W. [Technische Universitaet Dresden, D-01062 Dresden (Germany)

    2016-07-01

    In this paper we discuss a new phase of the Kondo lattice model which arises from the competition of Kondo and RKKY energy scales. Normally the Kondo lattice model is used to capture the low-energy physics of heavy fermion systems. However, according to the so-called Doniach picture the Kondo state will be replaced by an antiferromagnetic state for the case that the Kondo energy scale becomes smaller than the magnetic interaction between magnetic ions. In the present study we start instead from a modified electronic one-particle dispersion which avoids nesting of particle-hole excitations. Thus the magnetic ordered state should be suppressed which provides an opportunity for the inset of a new low-energy state with competing Kondo and magnetic energies. As will be shown, this new state avoids magnetic symmetry breaking but leads to a number of physical properties which are relevant for the understanding of the hidden order state in URu{sub 2}Si{sub 2}.

  18. A 3D Dynamic Lumped Parameter Thermal Network of Air-Cooled YASA Axial Flux Permanent Magnet Synchronous Machine

    Directory of Open Access Journals (Sweden)

    Abdalla Hussein Mohamed

    2018-03-01

    Full Text Available To find the temperature rise for high power density yokeless and segmented armature (YASA axial flux permanent magnet synchronous (AFPMSM machines quickly and accurately, a 3D lumped parameter thermal model is developed and validated experimentally and by finite element (FE simulations on a 4 kW YASA machine. Additionally, to get insight in the thermal transient response of the machine, the model accounts for the thermal capacitance of different machine components. The model considers the stator, bearing, and windage losses, as well as eddy current losses in the magnets on the rotors. The new contribution of this work is that the thermal model takes cooling via air channels between the magnets on the rotor discs into account. The model is parametrized with respect to the permanent magnet (PM angle ratio, the PM thickness ratio, the air gap length, and the rotor speed. The effect of the channels is incorporated via convection equations based on many computational fluid dynamics (CFD computations. The model accuracy is validated at different values of parameters by FE simulations in both transient and steady state. The model takes less than 1 s to solve for the temperature distribution.

  19. Changes of the more relevant PHTS parameters after the cleaning of the steam generators primary side at Embalse nuclear power plant

    International Nuclear Information System (INIS)

    Moreno, Carlos A.; Coutsiers, Ernesto; Acevedo, Paul; Pomerantz, Marcelo E.

    2003-01-01

    During the operation of the plant magnetite deposition occurs at the inner walls of Primary Heat Transport System (PHTS). This deposition is particularly significant at the U-tubes of steam generators. The consequence of this is the deterioration of heat transfer to the Secondary System. In order to minimize this impact, during the annual outage of 2000, the steam generators primary side cleaning by the SIVABLAST technique was carried out. This technique consists in blasting the inner walls with tiny stainless steel balls propelled by air at high pressure. This paper presents the change of the more relevant parameters of PHTS after that cleaning. The parameters analyzed and the main results are the following: 1) Inlet header temperature dropped 4.7 C degrees at full power; 2) Exit quality at the outlet headers decreased from 3,5% to 1,5%; 3) Global PHTS flow in single phase evaluated from: a) In-site instrumentation increased 4,6%; b) Thermalhydraulic code NUCIRC 1.0 increased 3,2%; c) measured flows at the instrumented fuel channels increased 4.4%. (author)

  20. Change in the order parameter of a superconductor of type I in the presence of magnetic dipoles

    International Nuclear Information System (INIS)

    Lebeau, C.; Pinel, J.

    1977-01-01

    Taking the order parameter to be spatially constant, we show that magnetic dipoles modify the energy with a term proportional to the difference between the local fields in the normal and supercondcuting states. Evaluation of this difference predicts a second-order transition. The transition temperature only depends on the mean value of ferromagnetic magnetisation. Specific heat and susceptibility measurements made on HgFe are compared with this model [fr

  1. Technological parameter effect on properties of sintered hard-magnetic type Nd-Fe-B materials

    International Nuclear Information System (INIS)

    Rastegaev, V.S.; Stepanova, G.I.; Gudim, Z.Yu.

    1989-01-01

    The effect of each technological operation on manufacturing hard magnets from Nd-Fe-B alloys on properties of sintered permanent magnets is studied. It is noted that violation of the metting regime can result in burn-up of boron and rare earths, and violation of the grinding mode-formation of nonmagnetic powder fractions, etc. Special attention is paid to material protection against oxidation by introducing passivating additions and creating of particular conditions for alloy sintering and heat treatment

  2. Natural remanent magnetization and rock magnetic parameters from the North-East Atlantic continental margin : Insights from a new, automated cryogenic magnetometer at the Geological Survey of Norway

    Science.gov (United States)

    Klug, Martin; Fabian, Karl; Knies, Jochen; Sauer, Simone

    2017-04-01

    Natural remanent magnetization (NRM) and rock magnetic parameters from two locations, West Barents Sea ( 71.6°N,16.2°E) and Vestnesa Ridge, NW Svalbard ( 79.0°N, 6.9°E), were acquired using a new, automatically operating cryogenic magnetometer system at the Geological Survey of Norway. The magnetometer setup comprises an automated robot sample feeding, dynamic operation and measurement monitoring, and customised output-to-database data handling. The setup is designed to dynamically enable a variety of parallel measurements with several coupled devices (e.g. balance, MS2B) to effectively use dead-time in between the otherwise time-consuming measurements with the cryogen magnetometer. Web-based access allows remote quality control and interaction 24/7 and enables high sample throughput. The magnetic properties are combined with geophysical, geochemical measurements and optical imaging, both radiographic and colour images, from high-resolution core-logging. The multidisciplinary approach enables determination and interpretation of content and formation of the magnetic fraction, and its development during diagenetic processes. Besides palaeomagnetic age determination the results offer the opportunity to study sediment transformation processes that have implications for the burial and degradation of organic matter. The results also help to understand long and short-term variability of sediment accumulation. Chemical sediment stability is directly linked to environmental and climate variability in the polar marine environment during the recent past.

  3. Two-order parameters theory of the metal-insulator phase transition kinetics in the magnetic field

    Science.gov (United States)

    Dubovskii, L. B.

    2018-05-01

    The metal-insulator phase transition is considered within the framework of the Ginzburg-Landau approach for the phase transition described with two coupled order parameters. One of the order parameters is the mass density which variation is responsible for the origin of nonzero overlapping of the two different electron bands and the appearance of free electron carriers. This transition is assumed to be a first-order phase one. The free electron carriers are described with the vector-function representing the second-order parameter responsible for the continuous phase transition. This order parameter determines mostly the physical properties of the metal-insulator transition and leads to a singularity of the surface tension at the metal-insulator interface. The magnetic field is involved into the consideration of the system. The magnetic field leads to new singularities of the surface tension at the metal-insulator interface and results in a drastic variation of the phase transition kinetics. A strong singularity in the surface tension results from the Landau diamagnetism and determines anomalous features of the metal-insulator transition kinetics.

  4. Magnetized target fusion: An ultra high energy approach in an unexplored parameter space

    International Nuclear Information System (INIS)

    Lindemuth, I.R.

    1994-01-01

    Magnetized target fusion is a concept that may lead to practical fusion applications in a variety of settings. However, the crucial first step is to demonstrate that it works as advertised. Among the possibilities for doing this is an ultrahigh energy approach to magnetized target fusion, one powered by explosive pulsed power generators that have become available for application to thermonuclear fusion research. In a collaborative effort between Los Alamos and the All-Russian Scientific Institute for Experimental Physics (VNIIEF) a very powerful helical generator with explosive power switching has been used to produce an energetic magnetized plasma. Several diagnostics have been fielded to ascertain the properties of this plasma. We are intensively studying the results of the experiments and calculationally analyzing the performance of this experiment

  5. Use of Magnetic Parameters to Asses Soil Erosion Rates on Agricultural Site

    Science.gov (United States)

    Petrovsky, E.; Kapicka, A.; Dlouha, S.; Jaksik, O.; Grison, H.; Kodesova, R.

    2014-12-01

    A detailed field study on a small test site of agricultural land situated in loess region in Southern Moravia (Czech Republic) and laboratory analyses were carried out in order to test the applicability of magnetic methods in assessing soil erosion. Haplic Chernozem, the original dominant soil unit in the area, is nowadays progressively transformed into different soil units along with intense soil erosion. As a result, an extremely diversified soil cover structure has developed due to the erosion. The site was characterized by a flat upper part while the middle part, formed by a substantive side valley, is steeper. We carried out field measurements of magnetic susceptibility on a regular grid, resulting in 101 data points. The bulk soil material for laboratory investigation was gathered from all the grid points. Values of the magnetic susceptibility are spatially distributed depending on the terrain. Higher values were measured in the flat upper part (where the original top horizon remained). The lowest values of were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). A soil profile unaffected by erosion was investigated in detail. The vertical distribution of magnetic susceptibility along this "virgin" profile was measured in laboratory on the samples collected with 2-cm spacing. The undisturbed profile shows several soil horizons. Horizons Ac and A show a slight increase in magnetic susceptibility up to a depth of about 70 cm. Horizon A/Ck is characterized by a decrease in susceptibility, and the underlying C horizon (h > 103 cm) has a very low value of magnetic susceptibility. The differences between the values of susceptibility in the undisturbed soil profile and the magnetic signal after uniform mixing the soil material as a result of tillage and erosion are fundamental for the estimation of soil loss in the studied test field. Using the uneroded profile from the studied locality as a

  6. The piezo-magnetic parameters of Terfenol-D: An experimental viewpoint

    International Nuclear Information System (INIS)

    Davino, D.; Giustiniani, A.; Visone, C.

    2012-01-01

    Magnetostrictive and all multifunctional materials have experienced in the last decades a growing technological interest. Several contributions, in the literature, propose the above-mentioned materials in innovative sensors and actuators both for bulk and MEMS devices. More recently, magnetostrictive materials have been proposed for energy harvesting applications by exploiting the so-called Villari effect. In this case, the behavior and the amplitude of the piezo-magnetic coefficients are an important element to evaluate the conversion efficiency. Aim of this paper is to study the experimental behavior of the piezo-magnetic coefficients of a commercial Terfenol-D rod under controlled conditions.

  7. Curie temperature and magnetic phase transition of nanostructured ultrathin Fe/GaAs (001). Size dependence and relevance of dipolar coupling

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Roland

    2009-07-01

    In the present work the impact of lateral patterning of ultrathin ferromagnetic films down to the nanometer range on the magnetic phase transition has been investigated. In this respect on the one hand a size effect on the Curie temperature and, referring to that, the relevance of dipolar coupling were a matter of particular interest. On the other hand the characteristics of the critical behavior itself, becoming apparent by the accurate evaluation of the curvature shape of the magnetization as a function of temperature at T{sub c}, were analyzed with regard to potential and expected size effects. The investigation of similar nanostructures with respect to an effect on Curie temperature respectively phase transition may draw up a correlation. Therefore more than hundred samples were fabricated for this work extensively by means of MBE (Molecular Beam Epitaxy) and ESL (Electron Beam Epitaxy) methods, measured by MOKE (Magneto-Optical Kerr Effect) technique and systematically evaluated. (orig.)

  8. Effect of sintering temperature on magnetization and Mössbauer parameters of cobalt ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Grish, E-mail: grishphysics@gmail.com [Department of Physics, DSB Campus Kumaun University, Nainital 263002, Uttarakhand (India); Srivastava, R.C. [Department of Physics, GB Pant University of Agriculture and Technology, Pantnagar, Uttarakhand (India); Reddy, V.R. [UGC-DAE CSR, Khandwa Road, DAVV Campus, Indore 452017, Madhya Pradesh (India); Agrawal, H.M. [Department of Physics, GB Pant University of Agriculture and Technology, Pantnagar, Uttarakhand (India)

    2017-04-01

    Nanoparticles of cobalt ferrite of different particle size were prepared using sol-gel method. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy techniques were employed for characterization of nanoparticles for structural and magnetic properties. The particle size and saturation magnetization increase with the increase of sintering temperature. The saturation magnetization increases from 53 to 85 emu/g as the sintering temperature increases from 300 to 900 °C. The remanence increases while the coercivity decreases slightly with the increase of sintering temperature. Mössbauer spectra show the ferrimagnetic nature of all the samples and the cation distribution strictly depends on the sintering temperature. The stoichiometry of the cobalt ferrite formed was estimated to be (Co{sup 2+}{sub x}Fe{sup 3+}{sub 1−x})[Co{sup 2+}{sub 1−x}Fe{sup 3+}{sub 1+x}]O{sub 4}, based on our Mössbauer analysis. The inverse spinel structure gradually transforms towards the normal spinel structure as the sintering temperature increases. - Highlights: • After 500 °C sintering the cobalt ferrite shows complete crystallization. • An inversion sintering temperature between 900 °C and 1200 °C is proposed where the Fe{sup +3} again starts migration from B site to A site. • Sintering temperature is one of the prime factors which effect the magnetization and cation distribution between two sites A and B.

  9. Magnetic and chemical parameters of andic soils and their relation to selected pedogenesis factors

    Czech Academy of Sciences Publication Activity Database

    Grison, Hana; Petrovský, Eduard; Kapička, Aleš; Stejskalová, Šárka

    2016-01-01

    Roč. 139, April (2016), s. 179-190 ISSN 0341-8162 R&D Projects: GA ČR GA13-10775S Institutional support: RVO:67985530 Keywords : andosols * magnetic susceptibility * basalts * iron oxides * frequency-dependent susceptibility Subject RIV: DF - Soil Science Impact factor: 3.191, year: 2016

  10. 3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

    Science.gov (United States)

    Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

    2014-02-01

    Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

  11. Magnetized strange quark matter in f(R, T) gravity with bilinear and special form of time varying deceleration parameter

    Science.gov (United States)

    Sahoo, P. K.; Sahoo, Parbati; Bishi, Binaya K.; Aygün, Sezgin

    2018-04-01

    In this paper, we have studied homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type-I model with magnetized strange quark matter (MSQM) distribution and cosmological constant Λ in f(R, T) gravity where R is the Ricci scalar and T the trace of matter source. The exact solutions of the field equations are obtained under bilinear and special form of time varying deceleration parameter (DP). Firstly, we have considered two specific forms of bilinear DP with a single parameter of the form: q = α(1-t)/1+t and q = -αt/1+t, which leads to the constant or linear nature of the function based on the constant α. Second one is the special form of the DP as q = - 1 + β/1+aβ. From the results obtained here, one can observe that in the early universe magnetic flux has more effects and it reduces gradually in the later stage. For t → ∞, we get p → -Bc and ρ → Bc. The behaviour of strange quark matter along with magnetic epoch gives an idea of accelerated expansion of the universe as per the observations of the type Ia Supernovae.

  12. Towards the blackbox computation of magnetic exchange coupling parameters in polynuclear transition-metal complexes: theory, implementation, and application.

    Science.gov (United States)

    Phillips, Jordan J; Peralta, Juan E

    2013-05-07

    We present a method for calculating magnetic coupling parameters from a single spin-configuration via analytic derivatives of the electronic energy with respect to the local spin direction. This method does not introduce new approximations beyond those found in the Heisenberg-Dirac Hamiltonian and a standard Kohn-Sham Density Functional Theory calculation, and in the limit of an ideal Heisenberg system it reproduces the coupling as determined from spin-projected energy-differences. Our method employs a generalized perturbative approach to constrained density functional theory, where exact expressions for the energy to second order in the constraints are obtained by analytic derivatives from coupled-perturbed theory. When the relative angle between magnetization vectors of metal atoms enters as a constraint, this allows us to calculate all the magnetic exchange couplings of a system from derivatives with respect to local spin directions from the high-spin configuration. Because of the favorable computational scaling of our method with respect to the number of spin-centers, as compared to the broken-symmetry energy-differences approach, this opens the possibility for the blackbox exploration of magnetic properties in large polynuclear transition-metal complexes. In this work we outline the motivation, theory, and implementation of this method, and present results for several model systems and transition-metal complexes with a variety of density functional approximations and Hartree-Fock.

  13. Linking Rock Magnetic Parameters and Tropical Paleoclimate in Postglacial Carbonates of the Tahitian Coral Reef

    Science.gov (United States)

    Platzman, E. S.; Lund, S.; Camoin, G.; Thouveny, N.

    2009-12-01

    In areas far away from active plate boundaries and previously glaciated regions, ecologically sensitive coral reefs provide an ideal laboratory for studying the timing and extent of deglaciation events as well as climatic change/variability at sub-millennial timescales. We have studied the Post Last-Glacial-Maximum (Post-LGM) coral reef terrace sediments recovered from the island of Tahiti on IODP Expedition 310. Samples for magnetic analysis were obtained from 632 meters of core from three reef tracts (Maraa, Tiarei, Faaa) surrounding the island (37 holes at 22 sites). The Post-LGM sediments are composed of >95% carbonate residing in a mixture of macroscopic framework corals, encrusting coralline algae, and bacterial microbialites (60% of the total core volume). Detailed paleomagnetic and rock magnetic measurements indicate that the microbialites carry a strong and stable natural magnetic remanence residing almost entirely in titanomagnetite derived from the Tahitian volcanic edifice. Within each tract, paleomagnetic results (inclination, relative paleointensity) were correlated to build a composite magnetic stratigraphy, which we could then compile with radiocarbon dates to develop an absolute chronostratigraphy. At the Maraa tract, for example, we use 54 radiocarbon dates to date our composite section to 7,500 to 13,500 cal. ybp. and demonstrate that the reef developed in a smooth and coherent manner over this interval. Overlaying the chronostratigraphy on measurements of the variation in magnetic properties including susceptibility, ARM, and IRM we can monitor changes in concentration, composition and grainsize of the influx of volcanogenic sediment over time. The ARM, IRM, and CHI intensities (normalized to sample weight) show a single strong peak between~9-10,000 years ago. We also observe a ~500-yr cyclicity in magnetic grain size and a clear increase in grain size associated with the Younger Dryas that we interpret to be related to rainfall variability. The

  14. Magnetic properties of natural pyrrhotite Part I : Behaviour of initial susceptibility and saturation-magnetization-related rock-magnetic parameters in a grain-size dependent framework

    NARCIS (Netherlands)

    Dekkers, M.J.

    1988-01-01

    The grain-size dependence of the initial susceptibility, saturation magnetization, saturation remanence , coercive force, remanent coercive force and remanent acquisition coercive force, is reported for four natural pyrrhotites in a grain-size range from 250 µm down to <5 µm.

  15. Li-ion battery ageing model parameter: SEI layer analysis using magnetic field probing

    Directory of Open Access Journals (Sweden)

    Parmender Singh

    2018-02-01

    Full Text Available With the growing usage of lithium-ion (Li-ion batteries in various applications from stationary applications to automotive industries, their ageing mechanism and its influencing factors have become a big concern today. Ageing may be defined as deterioration in the performance of the battery due to irreversible physical and chemical changes like internal resistance rise, electrolyte decompositions, electrodes cracking and solid electrolyte interphase (SEI modification/growth. The aim of this research article is to study and analyse the behaviour of SEI layer growth at the anode using a novel non-invasive magnetic field probing (MFP. A 3-d model based upon well-known John Newman’s pseudo 2-d approach has been developed in COMSOL Multiphysics®. It is observed that the magnetic field response (MFR is inversely related to SEI growth. Anode’s state of charge (SoC response with SEI layer and MFR is also studied.

  16. Criteria of interplanetary parameters causing intense magnetic storms (Dsub(st) < -100 nT)

    International Nuclear Information System (INIS)

    Gonzalez, W.D.; Tsurutani, B.T.

    1987-01-01

    Ten intense magnetic storms (Dsub(st) 5 mV m -1 , that last for intervals > 3 h. Because we find a one-to-one relationship between these interplanetary events and intense storms, we suggest that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. The close proximity of the Bsub(z) events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported and thus the two interplanetary features and corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity (northward) Bsub(z) events with the same criteria shows that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity. (author)

  17. A research technique for the effect of higher harmonic voltages on the operating parameters of a permanent magnet synchronous generator

    Directory of Open Access Journals (Sweden)

    Hasanova L. H.

    2017-12-01

    Full Text Available Nowadays permanent magnet synchronous machines those frequency-controlled from stator side with frequency inverters made on the basis of power transistors or fully controlled thyristors, are widely used as motors and generators. In future they are also promising a good application in transport, including marine. Modern frequency inverters are equipped with a control system based on sine-shaped pulse width modulation. While shaping the voltage in the output of the inverter, in addition to the fundamental harmonic, higher harmonic components are also included in the voltage shape, which certainly affect the operating parameters of the generator (electromagnetic torque, power, currents. To determine this effect the modeling and investigation technique of higher harmonic voltages in the "electric network – frequency converter – synchronous machine with permanent magnets" system has been developed. The proposed equations of a frequency-controlled permanent magnet synchronous machine allow relatively simply reproduce the harmonic composition of the voltage in the output of a frequency inverter equipped with the control system based on a sinusoidal pulse width modulation. The developed research technique can be used for inverters with any number and composition of voltage harmonic components feeding a stator winding of a permanent magnet synchronous machine. On a particular case, the efficiency of the research technique of the higher harmonics influence on the operating parameters of the generator has been demonstrated. At the same time, the study has been carried out taking into account the shape of the voltage curve feeding the windings of the synchronous machine containing in addition to the fundamental harmonic the 8, 10, 11, 13, 14 and 16-th harmonic components, and the rated active power of the synchronous machine has been equal to 1 500 kW.

  18. JUSTIFICATION OF PARAMETERS OF ROBOTIC MEANS WITH SPRAYER AND MODULE MAGNETIC-PULSE PROCESSING OF PLANTS IN HORTICULTURE

    Directory of Open Access Journals (Sweden)

    A. Yu. Izmaylov

    2017-01-01

    Full Text Available Robotic machines use in farming allows to create highly intellectual automated agricultural production, to replace completely a manual work, minimize the negative effects of chemicals on human and to reduce the losses of working hours connected with a human factor. The authors analyzed features of a design and technological using of the worked out in VIM robotic mean with a sprayer for low-growing cultures and the module of magnetic-pulse processing of plants in horticulture. Parameters of robotic mean are proved: engine capacity is 36 h.p., track width of forward wheels of 1260 mm, back ones - 1410 mm, a ground clearance height - 350 mm, the total length of the unit is 4900 mm, the smallest turning radius is 5.6 m. Feasibility and efficiency of implementation combined method of plants processing (spraying and magnetic-pulse processing by robotic means. This processing will make it possible to increase productivity by 25-30 percent due to stimulation of exchange processes in certain phases development of plants by weak low-frequency pulse magnetic fields in combination with additional synchronous radiation by light impulses 445 and 660 nanometers and targeted introduction of chemical crop-protection agents. Imitating mathematical modeling of mobility of a 3D robot model in the form set of bodies with various elastic characteristics in machine technologies of low-growing cultures cultivation in horticulture is carried out. Calculations dynamic behavior of robot body at various movement modes are made for model check. The schedules of robot movement parameters received subsequent to results of acceleration dynamics modeling are presented. The technique is offered and calculation of an indicator of local autonomy of task performance by unmanned robotic means for spraying with simultaneous magnetic-pulse processing of plants on the basis of the analysis of set of single indicators is made. Benefits of technological use robot in machine technologies

  19. Electrical and transcranial magnetic stimulation of the facial nerve: diagnostic relevance in acute isolated facial nerve palsy.

    Science.gov (United States)

    Happe, Svenja; Bunten, Sabine

    2012-01-01

    Unilateral facial weakness is common. Transcranial magnetic stimulation (TMS) allows identification of a conduction failure at the level of the canalicular portion of the facial nerve and may help to confirm the diagnosis. We retrospectively analyzed 216 patients with the diagnosis of peripheral facial palsy. The electrophysiological investigations included the blink reflex, preauricular electrical stimulation and the response to TMS at the labyrinthine part of the canalicular proportion of the facial nerve within 3 days after symptom onset. A similar reduction or loss of the TMS amplitude (p facial palsy without being specific for Bell's palsy. These data shed light on the TMS-based diagnosis of peripheral facial palsy, an ability to localize the site of lesion within the Fallopian channel regardless of the underlying pathology. Copyright © 2012 S. Karger AG, Basel.

  20. Getting Ready for BepiColombo: A Modeling Approach to Infer the Solar Wind Plasma Parameters Upstream of Mercury from Magnetic Field Observations

    Science.gov (United States)

    Fatemi, S.; Poirier, N.; Holmström, M.; Wieser, M.; Barabash, S.

    2018-05-01

    We have developed a model to infer the solar wind plasma parameters upstream of Mercury from magnetic field observations in Mercury's magnetosphere. This is important for observations by MESSENGER and the future mission to Mercury, BepiColombo.

  1. Design parameters for toroidal and bobbin magnetics. [conversion from English to metric units

    Science.gov (United States)

    Mclyman, W. T.

    1974-01-01

    The adoption by NASA of the metric system for dimensioning to replace long-used English units imposes a requirement on the U.S. transformer designer to convert from the familiar units to the less familiar metric equivalents. Material is presented to assist in that transition in the field of transformer design and fabrication. The conversion data makes it possible for the designer to obtain a fast and close approximation of significant parameters such as size, weight, and temperature rise. Nomographs are included to provide a close approximation for breadboarding purposes. For greater convenience, derivations of some of the parameters are also presented.

  2. Thermal effect on magnetic parameters of high-coercivity cobalt ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, E. F., E-mail: efchagas@fisica.ufmt.br; Ponce, A. S.; Prado, R. J.; Silva, G. M. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-MT (Brazil); Bettini, J. [Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, 13083-970 Campinas (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150 Urca. Rio de Janeiro (Brazil)

    2014-07-21

    We prepared very high-coercivity cobalt ferrite nanoparticles synthesized by a combustion method and using short-time high-energy mechanical milling to increase strain and the structural defects density. The coercivity (H{sub C}) of the milled sample reached 3.75 kOe—a value almost five times higher than that obtained for the non-milled material (0.76 kOe). To investigate the effect of the temperature on the magnetic behavior of the milled sample, we performed a thermal treatment on the milled sample at 300, 400, and 600 °C for 30 and 180 min. We analyzed the changes in the magnetic behavior of the nanoparticles due to the thermal treatment using the hysteresis curves, Williamson-Hall analysis, and transmission electron microscopy. The thermal treatment at 600 °C causes decreases in the microstructural strain and density of structural defects resulting in a significant decrease in H{sub C}. Furthermore, this thermal treatment increases the size of the nanoparticles and, as a consequence, there is a substantial increase in the saturation magnetization (M{sub S}). The H{sub C} of the samples treated at 600 °C for 30 and 180 min were 2.24 and 1.93 kOe, respectively, and the M{sub S} of these same samples increased from 57 emu/g to 66 and 70 emu/g, respectively. The H{sub C} and the M{sub S} are less affected by the thermal treatment at 300 and 400 °C.

  3. Effects of magnetic treated water on serum concentration parameters and fat thickness

    Directory of Open Access Journals (Sweden)

    Geraldo Balieiro Neto

    2013-02-01

    Full Text Available The goal of this study was to evaluate the effect of magnetic water on blood cells counts, biochemical profile, blood gas level and subcutaneous fat thickness of Jersey cows. This research was carried out at Agência Paulista de Tecnologia dos Agronegócios - APTA, SP. Twenty six Jersey cows from the APTA were allotted into two groups: control (n=13, drinking regular water and the group consuming magnetic water (n=13. The animals were lactating around 150 days and pregnant around 60 days. Blood samples were collected from caudal auricular artery and jugular vein. The water treatment had no effect on hemogram (p>0.05. Higher pH (7.448 vs 7.407 mmHg, p<0.05 and lower PaCO2 (37.97 vs 42.47 mmHg, p<0.05 levels were detected in arterial blood of the group drinking magnetic water. The concentration of Na ion (138.8 vs 145.5 mmol/l, p<0.05 and serum triglycerides (10.4 vs 22.6 mg/dL, p<0.05 were significantly lower, resulting in smaller osmolality (273.30 vs 280.99 mOsm/kg, p<0.05 and subcutaneous fat thickness (0.2 vs 1.3 mm, p<0.05. In summary, the water treatment, evaluated in this study, may have decreased the risk of some metabolic disorders, such as acidosis and high serum concentration of Na and carbon dioxide.

  4. Model reference adaptive control (MRAC)-based parameter identification applied to surface-mounted permanent magnet synchronous motor

    Science.gov (United States)

    Zhong, Chongquan; Lin, Yaoyao

    2017-11-01

    In this work, a model reference adaptive control-based estimated algorithm is proposed for online multi-parameter identification of surface-mounted permanent magnet synchronous machines. By taking the dq-axis equations of a practical motor as the reference model and the dq-axis estimation equations as the adjustable model, a standard model-reference-adaptive-system-based estimator was established. Additionally, the Popov hyperstability principle was used in the design of the adaptive law to guarantee accurate convergence. In order to reduce the oscillation of identification result, this work introduces a first-order low-pass digital filter to improve precision regarding the parameter estimation. The proposed scheme was then applied to an SPM synchronous motor control system without any additional circuits and implemented using a DSP TMS320LF2812. For analysis, the experimental results reveal the effectiveness of the proposed method.

  5. Fractional order sliding-mode control based on parameters auto-tuning for velocity control of permanent magnet synchronous motor.

    Science.gov (United States)

    Zhang, BiTao; Pi, YouGuo; Luo, Ying

    2012-09-01

    A fractional order sliding mode control (FROSMC) scheme based on parameters auto-tuning for the velocity control of permanent magnet synchronous motor (PMSM) is proposed in this paper. The control law of the proposed F(R)OSMC scheme is designed according to Lyapunov stability theorem. Based on the property of transferring energy with adjustable type in F(R)OSMC, this paper analyzes the chattering phenomenon in classic sliding mode control (SMC) is attenuated with F(R)OSMC system. A fuzzy logic inference scheme (FLIS) is utilized to obtain the gain of switching control. Simulations and experiments demonstrate that the proposed FROSMC not only achieve better control performance with smaller chatting than that with integer order sliding mode control, but also is robust to external load disturbance and parameter variations. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Deep Learning for Magnetic Resonance Fingerprinting: A New Approach for Predicting Quantitative Parameter Values from Time Series.

    Science.gov (United States)

    Hoppe, Elisabeth; Körzdörfer, Gregor; Würfl, Tobias; Wetzl, Jens; Lugauer, Felix; Pfeuffer, Josef; Maier, Andreas

    2017-01-01

    The purpose of this work is to evaluate methods from deep learning for application to Magnetic Resonance Fingerprinting (MRF). MRF is a recently proposed measurement technique for generating quantitative parameter maps. In MRF a non-steady state signal is generated by a pseudo-random excitation pattern. A comparison of the measured signal in each voxel with the physical model yields quantitative parameter maps. Currently, the comparison is done by matching a dictionary of simulated signals to the acquired signals. To accelerate the computation of quantitative maps we train a Convolutional Neural Network (CNN) on simulated dictionary data. As a proof of principle we show that the neural network implicitly encodes the dictionary and can replace the matching process.

  7. Test–bench for characterization of steady state magnetic sensors parameters in wide temperature range

    Czech Academy of Sciences Publication Activity Database

    Kovařík, Karel; Ďuran, Ivan; Sentkerestiová, J.; Šesták, David

    2013-01-01

    Roč. 88, 6-8 (2013), s. 1319-1322 ISSN 0920-3796. [Symposium on Fusion Technology (SOFT-27)/27./. Liège, 24.09.2012-28.09.2012] R&D Projects: GA MŠk 7G10072; GA ČR GAP205/10/2055; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : plasma * tokamak * Magnetic sensor testing * Hall sensor * Fusion device Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.149, year: 2013 http://www.sciencedirect.com/science/article/pii/S0920379613002652#

  8. Computer Simulation of Energy Parameters and Magnetic Effects in Fe-Si-C Ternary Alloys

    Science.gov (United States)

    Ridnyi, Ya. M.; Mirzoev, A. A.; Mirzaev, D. A.

    2018-06-01

    The paper presents ab initio simulation with the WIEN2k software package of the equilibrium structure and properties of silicon and carbon atoms dissolved in iron with the body-centered cubic crystal system of the lattice. Silicon and carbon atoms manifest a repulsive interaction in the first two nearest neighbors, in the second neighbor the repulsion being stronger than in the first. In the third and next-nearest neighbors a very weak repulsive interaction occurs and tends to zero with increasing distance between atoms. Silicon and carbon dissolution reduces the magnetic moment of iron atoms.

  9. Influence of R.F. sputter parameters on the magnetic orientation of Co-Cr layers

    NARCIS (Netherlands)

    Lodder, J.C.; Wielinga, T.

    1984-01-01

    Co-Cr layers for the perpendicular recording mode were deposited by means of RF-sputtering. The most important sputter parameters, i.e. the RF sputter high voltage VRF, the argon pressure Par and the substrate holder temperature Tsh, gave an optimum value for perpendicular orientation of the

  10. Variations in Solar Parameters and Cosmic Rays with Solar Magnetic Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S. [Department of Earth Science Education, Chonnam National University, Gwangju, 61186 (Korea, Republic of); Yi, Y., E-mail: suyeonoh@jnu.ac.kr [Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon, 34134 (Korea, Republic of)

    2017-05-01

    The sunspot number varies with the 11-year Schwabe cycle, and the solar magnetic polarity reverses every 11 years approximately at the solar maximum. Because of polarity reversal, the difference between odd and even solar cycles is seen in solar activity. In this study, we create the mean solar cycle expressed by phase using the monthly sunspot number for all solar cycles 1–23. We also generate the mean solar cycle for sunspot area, solar radio flux, and cosmic ray flux within the allowance of observational range. The mean solar cycle has one large peak at solar maximum for odd solar cycles and two small peaks for most even solar cycles. The odd and even solar cycles have the statistical difference in value and shape at a confidence level of at least 98%. For solar cycles 19–23, the second peak in the even solar cycle is larger than the first peak. This result is consistent with the frequent solar events during the declining phase after the solar maximum. The difference between odd and even solar cycles can be explained by a combined model of polarity reversal and solar rotation. In the positive/negative polarity, the polar magnetic field introduces angular momentum in the same/opposite direction as/to the solar rotation. Thus the addition/subtraction of angular momentum can increase/decrease the motion of plasma to support the formation of sunspots. Since the polarity reverses at the solar maximum, the opposite phenomenon occurs in the declining phase.

  11. Mechanical design parameters for detection of nuclear signals by magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    Moore, G.J.; Hanlon, J.A.; Lamartine, B.; Hawley, M.; Solem, J.C.; Signer, S.; Jarmer, J.J.; Penttila, S.; Sillerud, L.O.; Pryputniewicz, R.J.

    1993-01-01

    Recent theoretical work has shown that mechanical detection of magnetic resonance from a single nuclear spin is in principle possible. This theory has recently been experimentally validated by the mechanical detection of electron spin resonance signals using microscale cantilevers. Currently we are extending this technology in an attempt to detect nuclear signals which are extending this technology in an attempt to detect nuclear signals which are three orders of magnitude lower in intensity than electron signals. In order to achieve the needed thousand-fold improvement in sensitivity we have undertaken the development of optimized mechanical cantilevers and highly polarized samples. Finite element modeling is used as a tool to simulate cantilever beam dynamics and to optimize the mechanical properties including Q, resonant frequency, amplitude of vibration and spring constant. Simulations are compared to experiments using heterodyne hologram interferometry. Nanofabrication of optimized cantilevers via ion milling will be directed by the outcome of these simulations and experiments. Highly polarized samples are developed using a three-fold approach: (1) high magnetic field strength (2.5T), (2) low temperature (1K), and (3) use of samples polarized by dynamic nuclear polarization. Our recent experiments have demonstrated nuclear polarizations in excess of 50% in molecules of toulene

  12. Apparent Diffusion Coefficient and Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Pancreatic Cancer: Characteristics and Correlation With Histopathologic Parameters.

    Science.gov (United States)

    Ma, Wanling; Li, Na; Zhao, Weiwei; Ren, Jing; Wei, Mengqi; Yang, Yong; Wang, Yingmei; Fu, Xin; Zhang, Zhuoli; Larson, Andrew C; Huan, Yi

    2016-01-01

    To clarify diffusion and perfusion abnormalities and evaluate correlation between apparent diffusion coefficient (ADC), MR perfusion and histopathologic parameters of pancreatic cancer (PC). Eighteen patients with PC underwent diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Parameters of DCE-MRI and ADC of cancer and non-cancerous tissue were compared. Correlation between the rate constant that represents transfer of contrast agent from the arterial blood into the extravascular extracellular space (K, volume of the extravascular extracellular space per unit volume of tissue (Ve), and ADC of PC and histopathologic parameters were analyzed. The rate constant that represents transfer of contrast agent from the extravascular extracellular space into blood plasma, K, tissue volume fraction occupied by vascular space, and ADC of PC were significantly lower than nontumoral pancreases. Ve of PC was significantly higher than that of nontumoral pancreas. Apparent diffusion coefficient and K values of PC were negatively correlated to fibrosis content and fibroblast activation protein staining score. Fibrosis content was positively correlated to Ve. Apparent diffusion coefficient values and parameters of DCE-MRI can differentiate PC from nontumoral pancreases. There are correlations between ADC, K, Ve, and fibrosis content of PC. Fibroblast activation protein staining score of PC is negatively correlated to ADC and K. Apparent diffusion coefficient, K, and Ve may be feasible to predict prognosis of PC.

  13. SAE2.py: a python script to automate parameter studies using SCREAMER with application to magnetic switching on Z

    International Nuclear Information System (INIS)

    Orndorff-Plunkett, Franklin

    2011-01-01

    The SCREAMER simulation code is widely used at Sandia National Laboratories for designing and simulating pulsed power accelerator experiments on super power accelerators. A preliminary parameter study of Z with a magnetic switching retrofit illustrates the utility of the automating script for optimizing pulsed power designs. SCREAMER is a circuit based code commonly used in pulsed-power design and requires numerous iterations to find optimal configurations. System optimization using simulations like SCREAMER is by nature inefficient and incomplete when done manually. This is especially the case when the system has many interactive elements whose emergent effects may be unforeseeable and complicated. For increased completeness, efficiency and robustness, investigators should probe a suitably confined parameter space using deterministic, genetic, cultural, ant-colony algorithms or other computational intelligence methods. I have developed SAE2 - a user-friendly, deterministic script that automates the search for optima of pulsed-power designs with SCREAMER. This manual demonstrates how to make input decks for SAE2 and optimize any pulsed-power design that can be modeled using SCREAMER. Application of SAE2 to magnetic switching on model of a potential Z refurbishment illustrates the power of SAE2. With respect to the manual optimization, the automated optimization resulted in 5% greater peak current (10% greater energy) and a 25% increase in safety factor for the most highly stressed element.

  14. Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer

    DEFF Research Database (Denmark)

    Hanni, Matti; Lantto, Perttu; Ilias, Miroslav

    2007-01-01

    Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular...... interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full...... is obtained for d and ?s in Xe2. For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other...

  15. Impact reduction of the uncertain geometrical parameters on magnetic material identification of an EI electromagnetic inductor using an adaptive inverse algorithm

    International Nuclear Information System (INIS)

    Abdallh, A.; Crevecoeur, G.; Dupré, L.

    2012-01-01

    The magnetic characteristics of the electromagnetic devices' core materials can be recovered by solving an inverse problem, where sets of measurements need to be properly interpreted using a forward numerical model of the device. However, the uncertainties of the geometrical parameter values in the forward model lead to appreciable recovery errors in the recovered values of the material parameters. In this paper, we propose an effective inverse approach technique, in which the influences of the uncertainties in the geometrical model parameters are minimized. In this proposed approach, the cost function that needs to be minimized is adapted with respect to the uncertain geometrical model parameters. The proposed methodology is applied onto the identification of the magnetizing B–H curve of the magnetic material of an EI core inductor. The numerical results show a significant reduction of the recovery errors in the identified magnetic material parameter values. Moreover, the proposed methodology is validated by solving an inverse problem starting from real magnetic measurements. - Highlights: ► A new method to minimize the influence of the uncertain parameters in inverse problems is proposed. ► The technique is based on adapting iteratively the objective function that needs to be minimized. ► The objective function is adapted by the model response sensitivity to the uncertain parameters. ► The proposed technique is applied for recovering the B–H curve of an EI core inductor material. ► The error in the inverse problem solution is dramatically reduced using the proposed methodology.

  16. Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

    International Nuclear Information System (INIS)

    Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C; Chen, Y; Carota, G; Dackow, J; Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V

    2011-01-01

    BaZrO 3 (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I c ) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J c (θ) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J c (θ) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I c ), which clearly shows that BZO broadens the ab-plane peak and thus raises J c 5 0 -30 0 away from the tape plane, where the most critical approach to I c occurs in many coil designs. We describe some experimental procedures that may make critical current I c tests of these very high current tapes more tractable at 4.2 K, where I c exceeds 1000 A even for 4 mm wide tape with only 1 μm thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J c characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

  17. Properties of recent IBAD-MOCVD coated conductors relevant to their high field, low temperature magnet use

    Energy Technology Data Exchange (ETDEWEB)

    Braccini, V; Xu, A; Jaroszynski, J; Xin, Y; Larbalestier, D C [Applied Superconductivity Center, National High Magnetic Field Laboratory, 2031 E Paul Dirac Drive, Tallahassee, FL 32310 (United States); Chen, Y; Carota, G; Dackow, J [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Kesgin, I; Yao, Y; Guevara, A; Shi, T; Selvamanickam, V, E-mail: braccini@asc.magnet.fsu.edu [Department of Mechanical Engineering and the Texas Center for Superconductivity at the University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)

    2011-03-15

    BaZrO{sub 3} (BZO) nanorods are now incorporated into production IBAD-MOCVD coated conductors. Here we compare several examples of both BZO-free and BZO-containing coated conductors using critical current (I{sub c}) characterizations at 4.2 K over their full angular range up to fields of 31 T. We find that BZO nanorods do not produce any c-axis distortion of the critical current density J{sub c}({theta}) curve at 4.2 K at any field, but also that pinning is nevertheless strongly enhanced compared to the non-BZO conductors. We also find that the tendency of the ab-plane J{sub c}({theta}) peak to become cusp-like is moderated by BZO and we define a new figure of merit that may be helpful for magnet design-the OADI (off-axis double I{sub c}), which clearly shows that BZO broadens the ab-plane peak and thus raises J{sub c} 5{sup 0}-30{sup 0} away from the tape plane, where the most critical approach to I{sub c} occurs in many coil designs. We describe some experimental procedures that may make critical current I{sub c} tests of these very high current tapes more tractable at 4.2 K, where I{sub c} exceeds 1000 A even for 4 mm wide tape with only 1 {mu}m thickness of superconductor. A positive conclusion is that BZO is very beneficial for the J{sub c} characteristics at 4.2 K, just as it is at higher temperatures, where the correlated c-axis pinning effects of the nanorods are much more obvious.

  18. Relevance of near-Earth magnetic field modeling in deriving SEP properties using ground-based data

    Science.gov (United States)

    Kanellakopoulos, Anastasios; Plainaki, Christina; Mavromichalaki, Helen; Laurenza, Monica; Gerontidou, Maria; Storini, Marisa; Andriopoulou, Maria

    2014-05-01

    Ground Level Enhancements (GLEs) are short-term increases observed in cosmic ray intensity records of ground-based particle detectors such as neutron monitors (NMs) or muon detectors; they are related to the arrival of solar relativistic particles in the terrestrial environment. Hence, GLE events are related to the most energetic class of solar energetic particle (SEP) events. In this work we investigate how the use of different magnetospheric field models can influence the derivation of the relativistic SEP properties when modeling GLE events. As a case study, we examine the event of 2012 May 17 (also known as GLE71), registered by ground-based NMs. We apply the Tsyganenko 89 and the Tsyganenko 96 models in order to calculate the trajectories of the arriving SEPs in the near-Earth environment. We show that the intersection of the SEP trajectories with the atmospheric layer at ~20 km from the Earth's surface (i.e., where the flux of the generated secondary particles is maximum), forms for each ground-based neutron monitor a specified viewing region that is dependent on the magnetospheric field configuration. Then, we apply the Neutron Monitor Based Anisotropic GLE Pure Power Law (NMBANGLE PPOLA) model (Plainaki et al. 2010, Solar Phys, 264, 239), in order to derive the spectral properties of the related SEP event and the spatial distributions of the SEP fluxes impacting the Earth's atmosphere. We examine the dependence of the results on the used magnetic field models and evaluate their range of validity. Finally we discuss information derived by modeling the SEP spectrum in the frame of particle acceleration scenarios.

  19. Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

    Science.gov (United States)

    Swanson, Ryan D; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

    2015-01-01

    The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

  20. Studies of the Impact of Magnetic Field Uncertainties on Physics Parameters of the Mu2e Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bradascio, Federica [Pisa U.

    2016-01-01

    The Mu2e experiment at Fermilab will search for a signature of charged lepton flavor violation, an effect prohibitively too small to be observed within the Standard Model of particle physics. Therefore, its observation is a signal of new physics. The signature that Mu2e will search for is the ratio of the rate of neutrinoless coherent conversion of muons into electrons in the field of a nucleus, relative to the muon capture rate by the nucleus. The conversion process is an example of charged lepton flavor violation. This experiment aims at a sensitivity of four orders of magnitude higher than previous related experiments. The desired sensitivity implies highly demanding requirements of accuracy in the design and conduct of the experiment. It is therefore important to investigate the tolerance of the experiment to instrumental uncertainties and provide specifications that the design and construction must meet. This is the core of the work reported in this thesis. The design of the experiment is based on three superconducting solenoid magnets. The most important uncertainties in the magnetic field of the solenoids can arise from misalignments of the Transport Solenoid, which transfers the beam from the muon production area to the detector area and eliminates beam-originating backgrounds. In this thesis, the field uncertainties induced by possible misalignments and their impact on the physics parameters of the experiment are examined. The physics parameters include the muon and pion stopping rates and the scattering of beam electrons off the capture target, which determine the signal, intrinsic background and late-arriving background yields, respectively. Additionally, a possible test of the Transport Solenoid alignment with low momentum electrons is examined, as an alternative option to measure its field with conventional probes, which is technically difficult due to mechanical interference. Misalignments of the Transport Solenoid were simulated using standard

  1. Identifying parameters in active magnetic bearing system using LFT formulation and Youla factorization

    DEFF Research Database (Denmark)

    Lauridsen, Jonas; Sekunda, André Krabdrup; Santos, Ilmar

    2015-01-01

    the LFT matrices represent the mapping of the uncertainties in and out of the full and reduced FE system matrices. Scaling the LFT matrices easily leads to the amplitudes of the uncertainty parameters., Youla Parametrization method is applied to transform the identification problem into an open...... for model-based control design and fast identification., The paper elucidates how nodal parametric uncertainties, which are easily represented in the full FE coordinate system, can be represented in the new coordinate system of the reduced model. The uncertainty is described as a single column vector...... of the system matrix A of the full FE model while it is represented as several elements spread over multiple rows and columns of the system matrix of the reduced model. The parametric uncertainty, for both the full and reduced FE model, is represented using Linear Fractional Transformation (LFT). In this way...

  2. Functionalized Magnetic Resonance Contrast Agent Selectively Binds to Glycoprotein IIb/IIIa on Activated Human Platelets under Flow Conditions and Is Detectable at Clinically Relevant Field Strengths

    Directory of Open Access Journals (Sweden)

    Constantin von zur Mühlen

    2008-03-01

    Full Text Available Recent progress in molecular magnetic resonance imaging (MRI provides the opportunity to image cells and cellular receptors using microparticles of iron oxide (MPIOs. However, imaging targets on vessel walls remains challenging owing to the quantity of contrast agents delivered to areas of interest under shear stress conditions. We evaluated ex vivo binding characteristics of a functional MRI contrast agent to ligand-induced binding sites (LIBSs on activated glycoprotein IIb/IIIa receptors of human platelets, which were lining rupture-prone atherosclerotic plaques and could therefore facilitate detection of platelet-mediated pathology in atherothrombotic disease. MPIOs were conjugated to anti-LIBS single-chain antibodies (LIBS-MPIO or control antibodies (control MPIO. Ex vivo binding to human platelet-rich clots in a dose-dependent manner was confirmed on a 3 T clinical MRI scanner and by histology (p < .05 for LIBS-MPIO vs control MPIO. By using a flow chamber setup, significant binding of LIBS-MPIO to a platelet matrix was observed under venous and arterial flow conditions, but not for control MPIO (p < .001. A newly generated MRI contrast agent detects activated human platelets at clinically relevant magnetic field strengths and binds to platelets under venous and arterial flow conditions, conveying high payloads of contrast to specific molecular targets. This may provide the opportunity to identify vulnerable, rupture-prone atherosclerotic plaques via noninvasive MRI.

  3. Predicting surgical outcome in cases of cervical myelopathy with magnetic resonance imaging. Critical parameters

    International Nuclear Information System (INIS)

    Akiyama, Takashi

    1997-01-01

    In this study, the author attempted to correlate clinical factors significant in cases of cervical myelopathy with postoperative recovery. It is hoped that the results will aid in the preoperative prediction of surgical outcomes. The factors considered were the transverse area of the spinal cord, the cord compression rate, the presence of a high intensity area in T2-weighted MRI, the duration of symptoms before surgery, and age at surgery. Because there are variations in the transverse area of the spinal cord, 100 normal individuals were selected and the standard transverse area was calculated. The transverse area of the spinal cord and the cord constriction rate in the myelopathy cases was then measured and compared to the standard. The data indicated that the constriction rate was most relevant to recovery rate. Clinical thresholds found to correlate with a better than average rate of recovery in cases of cervical spondylotic myelopathy (CSM) were: a cord constriction rate; under 28.7%, cord compression rate; over 0.38, duration of symptoms before surgery; less than 9.2 months, and age at surgery; under 59.2 yrs. In patients with ossification of the longitudinal ligament (OPLL), cord constriction rate; under 36.2%, cord compression rate; over 0.30, duration of symptoms before surgery; less than 14.2 months, and age at surgery; under 57.6 yrs., all correlated with superior recovery, as did cord constriction rate; under 22.3%, and duration of symptoms before surgery; less than 3.7 months with patients suffering from cervical disc herniation (CDH). Furthermore, the absence of a T2-weighted high intensity area in CSM and OPLL patients also correlated with improved recovery. These results suggest that a favorable postoperative recovery rate can be expected in cases of cervical myelopathy that conform to the above criteria. (author)

  4. Effects of static magnetic field exposure on hematological and biochemical parameters in rats

    Directory of Open Access Journals (Sweden)

    Salem Amara

    2006-11-01

    Full Text Available The present work was undertaken in order to investigate the effects of static magnetic field (SMF on growth rates, hematopoiesis, plasmatic proteins levels, glucose concentration, lactate dehydrogenase (LDH and transaminases activities in male rats. Sub-acute exposure of rats during 5 consecutive days to SMF (1h/day at 128mT induced an increase of plasma LDH activity (+38%, pEste estudo foi realizado com o obejtivo de investigar os efeitos do campo magnético estático (CMS nas taxas de crescimento, hematopoiese, concentrações de proteínas plasmáticas, glicemia, da desidrogenase lática (DHL e transaminases (alanina aminotransferase-ALT e aspartato aminotransferase-AST em ratos machos. Após exposição de modo sub-agudo durante 5 dias consecutivos ao CMS (1 hora/dia, a 128mT, houve aumento em 38% na concentração de DHL (p<0.05, porém não houve mudanças nos índices hematimétricos, nas proteínas plasmáticas e nas transaminases. Duas semans após exposição ao CMS durante 30 dias consecutivos (CMS (1 hora/dia, a 128mT houve diminuição significativa das taxas de crescimento e aumento significativo das concetrações de proteínas (+62%, p<0.05, da hemoglobina (+10%, p<0.05, eritrócitos (+7%, p<0.05, leucócitos (+17%, p<0.05 e plaquetas (+10%, p<0.05. A exposição sub-crônica ao CMS induziu aumento da DHL (+43%, p<0.05, AST (+ 41%, p<0.05 e ALT (+95%, p<0.05. Em contraste não houve aumento da glicemia. Estas alterações sugerem que a exposição ao CMS possivelmente influencia a proliferação de células do sistema hematopoiético e a produção enzimática, indicando alterações teciduais.

  5. Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer.

    Science.gov (United States)

    Hanni, Matti; Lantto, Perttu; Ilias, Miroslav; Jensen, Hans Jorgen Aagaard; Vaara, Juha

    2007-10-28

    Relativistic effects on the (129)Xe nuclear magnetic resonance shielding and (131)Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe(2) system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift delta, the anisotropy of the shielding tensor Deltasigma, and the NQC constant along the internuclear axis chi( parallel) are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second-order Moller-Plesset many-body perturbation (DMP2) theory is used to examine the cross coupling between correlation and relativity on NQC. The same is investigated for delta and Deltasigma by BPPT with a density functional theory model. A semiquantitative agreement between the BPPT and DHF binary property curves is obtained for delta and Deltasigma in Xe(2). For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other hand, for the BPPT-based cross coupling of relativity and correlation. For chi( parallel), the fully relativistic DMP2 results obtain a correction for NR correlation effects beyond MP2. The computed temperature dependence of the second virial coefficient of the (129)Xe nuclear shielding is compared to experiment in Xe gas. Our best results, obtained with the piecewise approximation for the binary chemical shift combined with the

  6. An increase of structural order parameter in Fe endash Co endash V soft magnetic alloy after thermal aging

    International Nuclear Information System (INIS)

    Zhu, Q.; Li, L.; Masteller, M.S.; Del Corso, G.J.

    1996-01-01

    Alloys of Fe 49 Co 49 V 2 (Hiperco Alloy 50) (Hiperco is a registered trademark of CRS Holdings, Inc.), both annealed and thermally aged, were studied using anomalous synchrotron x-ray and neutron powder diffraction. Rietveld and diffraction profile analysis indicated both an increase in the structural order parameter and a small lattice expansion (∼0.0004 A) after aging at 450 degree C for 200 h. In addition, a cubic minority phase (<0.3%) was identified in the open-quote open-quote annealed close-quote close-quote sample, which increased noticeably (0.3%→0.8%) as a result of aging. The presence of antiphase domain boundaries in the alloys was also revealed. These results directly correlate with the observed changes in the magnetization behavior and challenge the notion that a open-quote open-quote fully close-quote close-quote ordered Fe endash Co alloy demonstrates optimum soft magnetic properties. copyright 1996 American Institute of Physics

  7. Effects of a static magnetic field of 3.5 T on reproductive behaviour of mice, embryonic and foetal development and some haematological parameters

    International Nuclear Information System (INIS)

    Zimmermann, B.; Hentschel, D.

    1987-01-01

    To investigate possibilities of magnetic resonance imaging at high magnetic fields in humans, a whole-body magnet with a magnetic field density of 4 T was developed. Due to the few data that are available at present on biological effects and side effects of such high fields, a reproduction experiment with NMRI mice was performed using a crossover design. The mice were allowed to mate during a 7-day period within the field or after their stay in the field. The number of pregnant mice and foetuses were recorded and compared to the controls. Another group was held within the magnetic field during the whole period of pregnancy until day 18, one day before delivery. In all groups, development of the foetuses was studied. Additionally, haematological parameters of the males and females were estimated and necroscopy was performed. Brains, lungs and optical nerves were investigated using pathohistological techniques. It could be shown that in case of mating within the magnetic field, the number of pregnant mice was considerably reduced. This effect was, however, completely reversible if mating occurred after the stay in the field. Malformations retardations or an increased number of resorptions were never found. The haematological parameters were, in general, not changed. Necroscopy as well as pathohistological investigations showed no pathological alterations. Therefore, it appears that whereas high magnetic fields reduce the activity of mating behaviour, they do not exert any influence on physiological parameters. (orig.) [de

  8. Magnets

    International Nuclear Information System (INIS)

    Young, I.R.

    1984-01-01

    A magnet pole piece for an NMR imaging magnet is made of a plurality of magnetic wires with one end of each wire held in a non-magnetic spacer, the other ends of the wires being brought to a pinch, and connected to a magnetic core. The wires may be embedded in a synthetic resin and the magnetisation and uniformity thereof can be varied by adjusting the density of the wires at the spacer which forms the pole piece. (author)

  9. SU-E-J-166: Sensitivity of Clinically Relevant Dosimetric Parameters to Contouring Uncertainty During Post Implant Dosimetry of Prostate Permanent Seed Implants

    Energy Technology Data Exchange (ETDEWEB)

    Mashouf, S [Sunnybrook Odette Cancer Centre, Toronto, ON (Canada); University of Toronto, Dept. of Radiation Oncology, Toronto, ON (Canada); Ravi, A; Morton, G; Song, W [Sunnybrook Odette Cancer Centre, Toronto, ON (Canada); University of Toronto, Dept. of Radiation Oncology, Toronto, ON (Canada); Sunnybrook Research Institute, Toronto, ON (Canada)

    2015-06-15

    Purpose: There is a strong evidence relating post-implant dosimetry for permanent seed prostate brachytherpy to local control rates. The delineation of the prostate on CT images, however, represents a challenge as it is difficult to confidently identify the prostate borders from soft tissue surrounding it. This study aims at quantifying the sensitivity of clinically relevant dosimetric parameters to prostate contouring uncertainty. Methods: The post-implant CT images and plans for a cohort of 43 patients, who have received I–125 permanent prostate seed implant in our centre, were exported to MIM Symphony LDR brachytherapy treatment planning system (MIM Software Inc., Cleveland, OH). The prostate contours in post-implant CT images were expanded/contracted uniformly for margins of ±1.00mm, ±2.00mm, ±3.00mm, ±4.00mm and ±5.00mm (±0.01mm). The values for V100 and D90 were extracted from Dose Volume Histograms for each contour and compared. Results: The mean value of V100 and D90 was obtained as 92.3±8.4% and 108.4±12.3% respectively (Rx=145Gy). V100 was reduced by −3.2±1.5%, −7.2±3.0%, −12.8±4.0%, −19.0±4.8%, − 25.5±5.4% for expanded contours of prostate with margins of +1mm, +2mm, +3mm, +4mm, and +5mm, respectively, while it was increased by 1.6±1.2%, 2.4±2.4%, 2.7±3.2%, 2.9±4.2%, 2.9±5.1% for the contracted contours. D90 was reduced by −6.9±3.5%, −14.5±6.1%, −23.8±7.1%, − 33.6±8.5%, −40.6±8.7% and increased by 4.1±2.6%, 6.1±5.0%, 7.2±5.7%, 8.1±7.3% and 8.1±7.3% for the same set of contours. Conclusion: Systematic expansion errors of more than 1mm may likely render a plan sub-optimal. Conversely contraction errors may Result in labeling a plan likely as optimal. The use of MRI images to contour the prostate should results in better delineation of prostate organ which increases the predictive value of post-op plans. Since observers tend to overestimate the prostate volume on CT, compared with MRI, the impact of the

  10. Combined Clinical Parameters and Multiparametric Magnetic Resonance Imaging for Advanced Risk Modeling of Prostate Cancer-Patient-tailored Risk Stratification Can Reduce Unnecessary Biopsies.

    Science.gov (United States)

    Radtke, Jan Philipp; Wiesenfarth, Manuel; Kesch, Claudia; Freitag, Martin T; Alt, Celine D; Celik, Kamil; Distler, Florian; Roth, Wilfried; Wieczorek, Kathrin; Stock, Christian; Duensing, Stefan; Roethke, Matthias C; Teber, Dogu; Schlemmer, Heinz-Peter; Hohenfellner, Markus; Bonekamp, David; Hadaschik, Boris A

    2017-12-01

    compared with RMs without PI-RADS and provided measurable benefit in making the decision to biopsy men at a suspicion of PC. For biopsy-naïve patients, both our RM and ERSPC-RC3 plus PI-RADSv1.0 exceeded the prediction performance compared with clinical parameters alone. Combined risk models including clinical and imaging parameters predict clinically relevant prostate cancer significantly better than clinical risk calculators and multiparametric magnetic resonance imaging alone. The risk models demonstrate a benefit in making a decision about which patient needs a biopsy and concurrently help avoid unnecessary biopsies. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  11. Detection of angiogenesis-dependent parameters by functional MRI: Correlation between histomorphology and evaluation of clinical relevance as prognostic factor for the example of cervical carcinoma

    International Nuclear Information System (INIS)

    Hawighorst, H.; Knopp, M.V.; Schoenberg, S.O.; Essig, M.; Kaick, G. van; Schaeffer, U.; Knapstein, P.G.; Weikel, W.

    1998-01-01

    Purpose: Purpose of this study is to compare functional MRI parameters with histomorphological markers of tumor microvessel density (MVD) and permeability (vascular endothelial growth factor) and to determine the ultimate value of both approaches by correlation with disease outcome in patients with primary cancer of the uterine cervix. Method: Pharmacokinetic parameters were calculated from contrast-enhanced dynamic MR imaging series in 37 patients with biopsy-proven primary cervical cancer. On the operative whole mount specimens, histomorphological markers of tumor angiogenesis (MVD, VEGF) were compared with the MRI-derived parameters. For MRI and histomorphological data, Kaplan-Meier survival curves were calculated and compared using logrank statistics. Results: Significant (p [de

  12. Relationships between nuclear magnetic resonance parameters used to characterize weathering spilled oil and soil toxicity in central Patagonia.

    Science.gov (United States)

    Ríos, Stella Maris; Barquin, Mercedes; Katusich, Ofelia; Nudelman, Norma

    2014-01-01

    Oil spill in the Central Patagonian zone was studied to evaluate if any relationship exists between the parameters used to characterize weathering spilled oil and soil toxicity for two plant species and to evaluate if the phytotoxicity to local species would be a good index for the soil contamination. Nuclear magnetic resonance (NMR) structural indexes and column chromatography compositional indexes were determined to characterize the oil spill in the soil samples. Bioassays were also carried out using Lactuca sativa L (reference) and Atriplex lampa (native species) as test organisms. Measurements of the total petroleum hydrocarbon (TPH) and the electrical conductivity (EC) of the soil were carried out to evaluate the effect on the bioassays. The principal components analysis of the parameters determined by NMR, compositional indexes, EC, TPH, and toxicology data shows that the first three principal components accounted for the 78% of the total variance (40%, 25%, and 13% for the first, second, and third PC, respectively). A good agreement was found between information obtained by compositional indexes and NMR structural indexes. Soil toxicity increases with the increase of EC and TPH. Other factors, such as, the presence of branched and aromatic hydrocarbons is also significant. The statistical evaluation showed that the Euclidean distances (3D) between the background and each one of the samples might be a better indicator of the soil contamination, compared with chemical criterion of TPH.

  13. SORTING CAPABILITIES OF CASTINGS FROM NODULAR AND GRAY IRON BY THE STRUCTURE BY THE RESULT OF THE MEASUREMENT OF THE MAGNETIC PARAMETERS AND THE SPEED OF SOUND

    Directory of Open Access Journals (Sweden)

    S. G. Sandomirskiy

    2013-01-01

    Full Text Available The results of the analysis of the influence of changes in the structure of the metal substrate and form of graphite inclusions in cast iron on the magnetic coercive sensitive parameter and the speed of sound are given. The efficiency of shared use of the results of magnetic and ultrasonic measurements to control the shape of inclusions in ductile iron and pearlite content in its metal matrix is shown.

  14. A facile approach to the elucidation of magnetic parameters of CuFe{sub 2}O{sub 4} nanoparticles synthesized by hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Kurian, Jessyamma [B.A.M. College, Thuruthicad, Mallappally, Kerala (India); Jacob Mathew, M., E-mail: jacob.chrisdale@gmail.com [S.B. College, Changanassery, Kerala (India)

    2017-04-15

    Pure pseudo cubic shaped copper ferrite nanoparticles with narrow size distribution in the range 6–17 nanometer are prepared by hydrothermal method under various synthesis conditions namely, hydrothermal temperature, heating time, and pH. The structural and morphological studies are carried out in detail using XRD and TEM analysis. The crystallite size and particle size are calculated from different characterization techniques. The distribution of cations among the tetrahedral and octahedral sites is determined from the XRD intensity calculation. Compositional features are determined from EDS analysis. Magnetic studies are carried out using VSM at room temperature and the important magnetic parameters are extracted from it. Contributions due to various types of magnetization to the total magnetization are determined from the theoretical fitting of the magnetization curve. Excellent fits are obtained for all samples prepared under various conditions. The ferromagnetic, superparamagnetic and paramagnetic contributions to the magnetization are determined from the analysis of fitted M-H curve. It is observed that the hydrothermal reaction time and temperature has little effect on the structural and magnetic parameters of the material. However, pH plays a crucial role in the physical properties of nanoparticles. Optimized synthesis conditions are identified for changing the soft ferrimagnetic nature of copper ferrite nanoparticles to superparamagnetic nature. - Highlights: • CuFe{sub 2}O{sub 4} particles of 6–17 nm size are produced by varying synthesis conditions. • Cubic single phase nano copper ferrite is obtained at a pH of 12. • Magnetic parameters calculated from theoretical fitting of M-H curves. • Dependence of the magnetic properties on Particle size and pH elucidated.

  15. MAGNET

    CERN Multimedia

    Benoit Curé

    The cooling down to the nominal temperature of 4.5 K was achieved at the beginning of August, in conjunction with the completion of the installation work of the connection between the power lines and the coil current leads. The temperature gradient on the first exchanger of the cold box is now kept within the nominal range. A leak of lubricant on a gasket of the helium compressor station installed at the surface was observed and several corrective actions were necessary to bring the situation back to normal. The compressor had to be refilled with lubricant and a regeneration of the filters and adsorbers was necessary. The coil cool down was resumed successfully, and the cryogenics is running since then with all parameters being nominal. Preliminary tests of the 20kA coil power supply were done earlier at full current through the discharge lines into the dump resistors, and with the powering busbars from USC5 to UXC5 without the magnet connected. On Monday evening August 25th, at 8pm, the final commissionin...

  16. MAGNET

    CERN Document Server

    B. Curé

    The first phase of the commissioning ended in August by a triggered fast dump at 3T. All parameters were nominal, and the temperature recovery down to 4.5K was carried out in two days by the cryogenics. In September, series of ramps were achieved up to 3 and finally 3.8T, while checking thoroughly the detectors in the forward region, measuring any movement of and around the HF. After the incident of the LHC accelerator on September 19th, corrective actions could be undertaken in the forward region. When all these displacements were fully characterized and repetitive, with no sign of increments in displacement at each field ramp, it was possible to start the CRAFT, Cosmic Run at Four Tesla (which was in fact at 3.8T). The magnet was ramped up to 18.16kA and the 3 week run went smoothly, with only 4 interruptions: due to the VIP visits on 21st October during the LHC inauguration day; a water leak on the cooling demineralized water circuit, about 1 l/min, that triggered a stop of the cooling pumps, and resulte...

  17. A study of MRI gradient echo signals from discrete magnetic particles with considerations of several parameters in simulations.

    Science.gov (United States)

    Kokeny, Paul; Cheng, Yu-Chung N; Xie, He

    2018-05-01

    Modeling MRI signal behaviors in the presence of discrete magnetic particles is important, as magnetic particles appear in nanoparticle labeled cells, contrast agents, and other biological forms of iron. Currently, many models that take into account the discrete particle nature in a system have been used to predict magnitude signal decays in the form of R2* or R2' from one single voxel. Little work has been done for predicting phase signals. In addition, most calculations of phase signals rely on the assumption that a system containing discrete particles behaves as a continuous medium. In this work, numerical simulations are used to investigate MRI magnitude and phase signals from discrete particles, without diffusion effects. Factors such as particle size, number density, susceptibility, volume fraction, particle arrangements for their randomness, and field of view have been considered in simulations. The results are compared to either a ground truth model, theoretical work based on continuous mediums, or previous literature. Suitable parameters used to model particles in several voxels that lead to acceptable magnetic field distributions around particle surfaces and accurate MR signals are identified. The phase values as a function of echo time from a central voxel filled by particles can be significantly different from those of a continuous cubic medium. However, a completely random distribution of particles can lead to an R2' value which agrees with the prediction from the static dephasing theory. A sphere with a radius of at least 4 grid points used in simulations is found to be acceptable to generate MR signals equivalent from a larger sphere. Increasing number of particles with a fixed volume fraction in simulations reduces the resulting variance in the phase behavior, and converges to almost the same phase value for different particle numbers at each echo time. The variance of phase values is also reduced when increasing the number of particles in a fixed

  18. Effects of dynamic diffraction conditions on magnetic parameter determination in a double perovskite Sr{sub 2}FeMoO{sub 6} using electron energy-loss magnetic chiral dichroism

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.C. [National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhong, X.Y., E-mail: xyzhong@mail.tsinghua.edu.cn [National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Jin, L. [Peter Grünberg Institute and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, 52425 Jülich (Germany); Chen, X.F. [National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Moritomo, Y. [Graduate School of Pure & Applied Science and Faculty of Pure & Applied Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-7571 (Japan); Mayer, J. [Peter Grünberg Institute and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, 52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen (Germany)

    2017-05-15

    Electron energy-loss magnetic chiral dichroism (EMCD) spectroscopy, which is similar to the well-established X-ray magnetic circular dichroism spectroscopy (XMCD), can determine the quantitative magnetic parameters of materials with high spatial resolution. One of the major obstacles in quantitative analysis using the EMCD technique is the relatively poor signal-to-noise ratio (SNR), compared to XMCD. Here, in the example of a double perovskite Sr{sub 2}FeMoO{sub 6}, we predicted the optimal dynamical diffraction conditions such as sample thickness, crystallographic orientation and detection aperture position by theoretical simulations. By using the optimized conditions, we showed that the SNR of experimental EMCD spectra can be significantly improved and the error of quantitative magnetic parameter determined by EMCD technique can be remarkably lowered. Our results demonstrate that, with enhanced SNR, the EMCD technique can be a unique tool to understand the structure-property relationship of magnetic materials particularly in the high-density magnetic recording and spintronic devices by quantitatively determining magnetic structure and properties at the nanometer scale. - Highlights: • We demonstrate how to choose the optimal experimental conditions by using dynamical diffraction calculations in Sr{sub 2}FeMoO{sub 6}. • With optimized diffraction conditions, the signal-to-noise ratio of experimental EMCD spectra has been significantly improved. • We have determined orbital to spin magnetic moment ratio of Sr{sub 2}FeMoO{sub 6} quantitatively. • We have discussed the effects of dynamical diffraction conditions on the error bar of quantitative magnetic parameters.

  19. Predicting Collateral Status With Magnetic Resonance Perfusion Parameters: Probabilistic Approach With a Tmax-Derived Prediction Model.

    Science.gov (United States)

    Lee, Mi Ji; Son, Jeong Pyo; Kim, Suk Jae; Ryoo, Sookyung; Woo, Sook-Young; Cha, Jihoon; Kim, Gyeong-Moon; Chung, Chin-Sang; Lee, Kwang Ho; Bang, Oh Young

    2015-10-01

    Good collateral flow is an important predictor for favorable responses to recanalization therapy and successful outcomes after acute ischemic stroke. Magnetic resonance perfusion-weighted imaging (MRP) is widely used in patients with stroke. However, it is unclear whether the perfusion parameters and thresholds would predict collateral status. The present study evaluated the relationship between hypoperfusion severity and collateral status to develop a predictive model for good collaterals using MRP parameters. Patients who were eligible for recanalization therapy that underwent both serial diffusion-weighted imaging and serial MRP were enrolled into the study. A collateral flow map derived from MRP source data was generated through automatic postprocessing. Hypoperfusion severity, presented as proportions of every 2-s Tmax strata to the entire hypoperfusion volume (Tmax≥2 s), was compared between patients with good and poor collaterals. Prediction models for good collaterals were developed with each Tmax strata proportion and cerebral blood volumes. Among 66 patients, 53 showed good collaterals based on MRP-based collateral grading. Although no difference was noted in delays within 16 s, more severe Tmax delays (Tmax16-18 s, Tmax18-22 s, Tmax22-24 s, and Tmax>24 s) were associated with poor collaterals. The probability equation model using Tmax strata proportion demonstrated high predictive power in a receiver operating characteristic analysis (area under the curve=0.9303; 95% confidence interval, 0.8682-0.9924). The probability score was negatively correlated with the volume of infarct growth (P=0.030). Collateral status is associated with more severe Tmax delays than previously defined. The present Tmax severity-weighted model can determine good collaterals and subsequent infarct growth. © 2015 American Heart Association, Inc.

  20. Impact of the Parameter Variation on the Image Blurring in 3 T Magnetic Resonance Imaging: A Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Woo; Lee, Sang Hoon; Kim, Nam Kug; Cho, Kyung Sik; Lee, Jin Seong [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2013-04-15

    To evaluate the effects of the key imaging-parameter alterations on the four MR sequences in a phantom study. Magnetic resonance (MR) imaging was performed on a MR phantom with an 8-channel head coil by using a 3 T MR system. The images were obtained in the axial plane on four MR sequences [T1-weighted, T2-weighted, Proton-density, and 3 dimensional (3D) fast spin echo (FSE)] with controlled variations in the following key parameters: 1) echo train length (ETL), 2) repetition time (TR), and 3) echo time (TE). The image blurring was determined by the degree of the gradient angle; i.e., the blurring increased as the gradient angle decreases. The increasing ETL was observed to cause an increase in the image blurring on all pulse sequences with a statistical significance (p = 0.004) on the 3D FSE. Increasing the TR appeared to have no effect except a statistically significant decrease on the T1-weighted images (p = 0.011). Increasing TE showed no effect on the T1-weighted images (p = 0.932); however, it caused an increase of blurring on the proton density images (p = 0.016) as well as the T2-weighted images (p < 0.001), and a decrease on the 3D FSE (p = 0.001). To reduce the image blurring, short ETL and long TE for 3D FSE, long TR for T1-weighted images and short TE for proton-density and T2-weighted images should be applied.

  1. An In Vitro Approach to Study Effects of Prebiotics and Probiotics on the Faecal Microbiota and Selected Immune Parameters Relevant to the Elderly.

    Science.gov (United States)

    Liu, Yue; Gibson, Glenn R; Walton, Gemma E

    2016-01-01

    The aging process leads to alterations of gut microbiota and modifications to the immune response, such changes may be associated with increased disease risk. Prebiotics and probiotics can modulate microbiome changes induced by aging; however, their effects have not been directly compared. The aim of this study was to use anaerobic batch culture fermenters to assess the impact of various fermentable carbohydrates and microorganisms on the gut microbiota and selected immune markers. Elderly volunteers were used as donors for these experiments to enable relevance to an aging population. The impact of fermentation supernatants on immune markers relevant to the elderly were assessed in vitro. Levels of IL-1β, IL-6, IL-8, IL-10 and TNF-α in peripheral blood mononuclear cell culture supernatants were measured using flow cytometry. Trans-galactooligosaccharides (B-GOS) and inulin both stimulated bifidobacteria compared to other treatments (pprebiotics and probiotics could lead to potentially beneficial effects to host health by targeting specific bacterial groups, increasing saccharolytic fermentation and decreasing inflammation associated with aging. Compared to probiotics, prebiotics led to greater microbiota modulation at the genus level within the fermenters.

  2. Analysis of water sorption isotherms of amorphous food materials by solution thermodynamics with relevance to glass transition: evaluation of plasticizing effect of water by the thermodynamic parameters.

    Science.gov (United States)

    Shimazaki, Eriko; Tashiro, Akiko; Kumagai, Hitomi; Kumagai, Hitoshi

    2017-04-01

    Relation between the thermodynamic parameters obtained from water sorption isotherms and the degree of reduction in the glass transition temperature (T g ), accompanied by water sorption, was quantitatively studied. Two well-known glassy food materials namely, wheat gluten and maltodextrin were used as samples. The difference between the chemical potential of water in a solution and that of pure water ([Formula: see text]), the difference between the chemical potential of solid in a solution and that of a pure solid ([Formula: see text]), and the change in the integral Gibbs free energy ([Formula: see text]) were obtained by analyzing the water sorption isotherms using solution thermodynamics. The parameter [Formula: see text] correlated well with ΔT g (≡T g  - T g0 ; where T g0 is the glass transition temperature of dry material), which had been taken to be an index of plasticizing effect. This indicates that plasticizing effect of water on foods can be evaluated through the parameter [Formula: see text].

  3. Design of a Data Catalogue for Perdigão-2017 Field Experiment: Establishing the Relevant Parameters, Post-Processing Techniques and Users Access

    Science.gov (United States)

    Palma, J. L.; Belo-Pereira, M.; Leo, L. S.; Fernando, J.; Wildmann, N.; Gerz, T.; Rodrigues, C. V.; Lopes, A. S.; Lopes, J. C.

    2017-12-01

    Perdigão is the largest of a series of wind-mapping studies embedded in the on-going NEWA (New European Wind Atlas) Project. The intensive observational period of the Perdigão field experiment resulted in an unprecedented volume of data, covering several wind conditions through 46 consecutive days between May and June 2017. For researchers looking into specific events, it is time consuming to scrutinise the datasets looking for appropriate conditions. Such task becomes harder if the parameters of interest were not measured directly, instead requiring their computation from the raw datasets. This work will present the e-Science platform developed by University of Porto for the Perdigao dataset. The platform will assist scientists of Perdigao and the larger scientific community in extrapolating the datasets associated to specific flow regimes of interest as well as automatically performing post-processing/filtering operations internally in the platform. We will illustrate the flow regime categories identified in Perdigao based on several parameters such as weather type classification, cloud characteristics, as well as stability regime indicators (Brunt-Väisälä frequency, Scorer parameter, potential temperature inversion heights, dimensionless Richardson and Froude numbers) and wind regime indicators. Examples of some of the post-processing techniques available in the e-Science platform, such as the Savitzky-Golay low-pass filtering technique, will be also presented.

  4. Magnetic resonance imaging in assessment of stress urinary incontinence in women: Parameters differentiating urethral hypermobility and intrinsic sphincter deficiency.

    Science.gov (United States)

    Macura, Katarzyna Jadwiga; Thompson, Richard Eugene; Bluemke, David Alan; Genadry, Rene

    2015-11-28

    To define the magnetic resonance imaging (MRI) parameters differentiating urethral hypermobility (UH) and intrinsic sphincter deficiency (ISD) in women with stress urinary incontinence (SUI). The static and dynamic MR images of 21 patients with SUI were correlated to urodynamic (UD) findings and compared to those of 10 continent controls. For the assessment of the urethra and integrity of the urethral support structures, we applied the high-resolution endocavitary MRI, such as intraurethral MRI, endovaginal or endorectal MRI. For the functional imaging of the urethral support, we performed dynamic MRI with the pelvic phased array coil. We assessed the following MRI parameters in both the patient and the volunteer groups: (1) urethral angle; (2) bladder neck descent; (3) status of the periurethral ligaments, (4) vaginal shape; (5) urethral sphincter integrity, length and muscle thickness at mid urethra; (6) bladder neck funneling; (7) status of the puborectalis muscle; (8) pubo-vaginal distance. UDs parameters were assessed in the patient study group as follows: (1) urethral mobility angle on Q-tip test; (2) Valsalva leak point pressure (VLPP) measured at 250 cc bladder volume; and (3) maximum urethral closure pressure (MUCP). The UH type of SUI was defined with the Q-tip test angle over 30 degrees, and VLPP pressure over 60 cm H2O. The ISD incontinence was defined with MUCP pressure below 20 cm H2O, and VLPP pressure less or equal to 60 cm H2O. We considered the associations between the MRI and clinical data and UDs using a variety of statistical tools to include linear regression, multivariate logistic regression and receiver operating characteristic (ROC) analysis. All statistical analyses were performed using STATA version 9.0 (StataCorp LP, College Station, TX). In the incontinent group, 52% have history of vaginal delivery trauma as compared to none in control group (P continent volunteers and incontinent patients in body habitus as assessed by the body mass

  5. Magnetic hyperthermia properties of nanoparticles inside lysosomes using kinetic Monte Carlo simulations: Influence of key parameters and dipolar interactions, and evidence for strong spatial variation of heating power

    Science.gov (United States)

    Tan, R. P.; Carrey, J.; Respaud, M.

    2014-12-01

    Understanding the influence of dipolar interactions in magnetic hyperthermia experiments is of crucial importance for fine optimization of nanoparticle (NP) heating power. In this study we use a kinetic Monte Carlo algorithm to calculate hysteresis loops that correctly account for both time and temperature. This algorithm is shown to correctly reproduce the high-frequency hysteresis loop of both superparamagnetic and ferromagnetic NPs without any ad hoc or artificial parameters. The algorithm is easily parallelizable with a good speed-up behavior, which considerably decreases the calculation time on several processors and enables the study of assemblies of several thousands of NPs. The specific absorption rate (SAR) of magnetic NPs dispersed inside spherical lysosomes is studied as a function of several key parameters: volume concentration, applied magnetic field, lysosome size, NP diameter, and anisotropy. The influence of these parameters is illustrated and comprehensively explained. In summary, magnetic interactions increase the coercive field, saturation field, and hysteresis area of major loops. However, for small amplitude magnetic fields such as those used in magnetic hyperthermia, the heating power as a function of concentration can increase, decrease, or display a bell shape, depending on the relationship between the applied magnetic field and the coercive/saturation fields of the NPs. The hysteresis area is found to be well correlated with the parallel or antiparallel nature of the dipolar field acting on each particle. The heating power of a given NP is strongly influenced by a local concentration involving approximately 20 neighbors. Because this local concentration strongly decreases upon approaching the surface, the heating power increases or decreases in the vicinity of the lysosome membrane. The amplitude of variation reaches more than one order of magnitude in certain conditions. This transition occurs on a thickness corresponding to approximately

  6. An In Vitro Approach to Study Effects of Prebiotics and Probiotics on the Faecal Microbiota and Selected Immune Parameters Relevant to the Elderly.

    Directory of Open Access Journals (Sweden)

    Yue Liu

    Full Text Available The aging process leads to alterations of gut microbiota and modifications to the immune response, such changes may be associated with increased disease risk. Prebiotics and probiotics can modulate microbiome changes induced by aging; however, their effects have not been directly compared. The aim of this study was to use anaerobic batch culture fermenters to assess the impact of various fermentable carbohydrates and microorganisms on the gut microbiota and selected immune markers. Elderly volunteers were used as donors for these experiments to enable relevance to an aging population. The impact of fermentation supernatants on immune markers relevant to the elderly were assessed in vitro. Levels of IL-1β, IL-6, IL-8, IL-10 and TNF-α in peripheral blood mononuclear cell culture supernatants were measured using flow cytometry. Trans-galactooligosaccharides (B-GOS and inulin both stimulated bifidobacteria compared to other treatments (p<0.05. Fermentation supernatants taken from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus and Ba. coagulans inhibited LPS induced TNF-α (p<0.05. IL-10 production, induced by LPS, was enhanced by fermentation supernatants from faecal batch cultures supplemented with B-GOS, inulin, B. bifidum, L. acidophilus, Ba. coagulans and Bac. thetaiotaomicron (p<0.05. To conclude, prebiotics and probiotics could lead to potentially beneficial effects to host health by targeting specific bacterial groups, increasing saccharolytic fermentation and decreasing inflammation associated with aging. Compared to probiotics, prebiotics led to greater microbiota modulation at the genus level within the fermenters.

  7. Coupling between magnetic and superconducting order parameters and evidence for the spin excitation gap in the superconducting state of a heavy fermion superconductor UPd2Al3

    International Nuclear Information System (INIS)

    Metoki, Naoto; Haga, Yoshinori; Koike, Yoshihiro; Aso, Naofumi; Onuki, Yoshichika

    1997-01-01

    Neutron scattering experiments have been carried out in order to study the interplay between magnetism and superconductivity in a heavy fermion superconductor, UPd 2 Al 3 . We have observed 1% suppression of the (0 0 0.5) magnetic peak intensity below the superconducting transition temperature T c . This is direct evidence for the coupling of the magnetic order parameter with the superconducting one. Furthermore, we have observed a spin excitation gap associated with superconductivity. The gap energy ΔE g increases continuously from ΔE g =0 to 0.4 meV with decreasing temperature from T c to 0.4 K. This gap energy corresponds to 2k B T c , which is smaller than the superconducting gap expected from the BCS theory (3.5k B T c ). These results are indicative of the strong interplay between magnetism and superconductivity. (author)

  8. Oral delivery of live yeast Debaryomyces hansenii modulates the main innate immune parameters and the expression of immune-relevant genes in the gilthead seabream (Sparus aurata L.).

    Science.gov (United States)

    Reyes-Becerril, Martha; Salinas, Irene; Cuesta, Alberto; Meseguer, José; Tovar-Ramirez, Dariel; Ascencio-Valle, Felipe; Esteban, Maria Angeles

    2008-12-01

    Microorganisms isolated from fish can be used as prophylactic tools for aquaculture in the form of probiotic preparations. The purpose of this study was to evaluate the effects of dietary administration of the live yeast Debaryomyces hansenii CBS 8339 on the gilthead seabream (Sparus aurata L.) innate immune responses. Seabream were fed control or D. hansenii-supplemented diets (10(6) colony forming units, CFU g(-1)) for 4 weeks. Humoral (seric alternative complement and peroxidase activities), and cellular (peroxidase, phagocytic, respiratory burst and cytotoxic activities) innate immune parameters and antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were measured from serum, head-kidney leucocytes and liver, respectively, after 2 and 4 weeks of feeding. Expression levels of immune-associated genes, Hep, IgM, TCR-beta, NCCRP-1, MHC-II alpha, CSF-1R, C3, TNF-alpha and IL-1 beta, were also evaluated by real-time PCR in head-kidney, liver and intestine. Humoral immune parameters were not significantly affected by the dietary supplementation of yeast at any time of the experiment. On the other hand, D. hansenii administration significantly enhanced leucocyte peroxidase and respiratory burst activity at week 4. Phagocytic and cytotoxic activities had significantly increased by week 2 of feeding yeast but unchanged by week 4. A significant increase in liver SOD activity was observed at week 2 of feeding with the supplemented diet; however CAT activity was not affected by the dietary yeast supplement at any time of the experiment. Finally, the yeast supplemented diet down-regulated the expression of most seabream genes, except C3, in liver and intestine and up-regulated all of them in the head-kidney. These results strongly support the idea that live yeast Debaryomyces hansenii strain CBS 8339 can stimulate the innate immune parameters in seabream, especially at cellular level.

  9. MAGNET

    CERN Multimedia

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  10. Study of the anatomical position of the femoral nerve by magnetic resonance imaging in patients with fractured neck of femur: relevance to femoral nerve block.

    LENUS (Irish Health Repository)

    Mehmood, Shehzad

    2012-01-31

    STUDY OBJECTIVE: To determine the anatomical location of the femoral nerve in patients who have sustained fracture of the neck of femur, and its relevance to femoral nerve block technique. DESIGN: Prospective, observational clinical study. SETTING: Orthopedic and Radiology departments of a regional hospital. SUBJECTS: 10 consecutive adult ASA physical status II and III patients (mean age, 78.5 yrs) and 4 adult healthy volunteers. INTERVENTIONS: A T1 magnetic resonance imaging scan was performed of both upper thighs in patients and healthy volunteers successfully. MEASUREMENTS: The distance (mm) between the midpoint of the femoral artery and the midpoint of the femoral nerve, and the distance of the femoral nerve from the skin was measured at the mid-inguinal ligament, the pubic tubercle, and at the mid-inguinal crease. Data are shown as means (SD). Differences between both sides were compared using paired Student\\'s t-tests. P < 0.05 was significant. MAIN RESULTS: In patients the mean distance (mm) between the midpoint of the femoral nerve from the midpoint of femoral artery at the mid-inguinal crease on the fractured and non-fractured sides was 10.7 and 11.0, respectively (P = 0.87). The mean distance (mm) between the midpoint of the femoral nerve from the midpoint of the femoral artery at the mid-inguinal ligament on the fractured and non-fractured sides was 9.64 and 12.5, respectively (P = 0.03). The mean distance (mm) between the midpoint of the femoral nerve from the midpoint of the femoral artery at the pubic tubercle on the fractured and non-fractured sides was 8.74 and 10.49, respectively (P = 0.18). CONCLUSIONS: Blockade of the femoral nerve may be easier to perform at the mid-inguinal crease in patients with fractured neck of femur.

  11. Measurement of track opening contours of oblique incident 4He and 7Li-ions in CR-39: Relevance for calculation of track formation parameters

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Reichelt, U.

    2010-01-01

    Solid State Nuclear Track Detectors (SSNTD) irradiated in realistic radiation fields exhibits after chemical etching very complex track images resulting from different species of particles and their energy spectra and randomly distributed angles of incidence or emission. Reading out such an etched detector surface with a light microscope, quite different track opening contours are observed. Beside the number of tracks, typically their major and minor axes are measured. In this work following problems arising from such experimental situations will be investigated: ·the measurement of track contour parameters for oblique incident 4 He and 7 Li-ions of different energies and angles in CR-39 detectors ·the theoretical description of the angular variation of both axes. ·the possibility to extract physical and spectroscopic information from major and minor track axes. This analysis is based on an intensive experimental program and the comprehensive study of theoretical models available for description of track revealing processes in CR-39.

  12. Effect of the resonant magnetic perturbation on the plasma parameters in COMPASS tokamak’s divertor region

    Science.gov (United States)

    Dimitrova, M.; Cahyna, P.; Peterka, M.; Hasan, E.; Popov, Tsv K.; Ivanova, P.; Vasileva, E.; Panek, R.; Cavalier, J.; Seidl, J.; Markovic, T.; Havlicek, J.; Dejarnac, R.; Weinzettl, V.; Hacek, P.; Tomes, M.; the COMPASS Team; the EUROfusion MST1 Team

    2018-02-01

    The resonant magnetic perturbation (RMP) has proven to be a useful way to suppress edge-localized modes that under certain conditions can damage the device by the large power fluxes carried from the bulk plasma to the wall. The effect of RMP on the L-mode plasma parameters in the divertor region of the COMPASS tokamak was studied using the array of 39 Langmuir probes embedded into the divertor target. The current-voltage (IV) probe characteristics were processed by the first-derivative probe technique to obtain the plasma potential and the electron energy distribution function (EEDF) which was approximated by a bi-Maxwellian EEDF with a low-energy (4-6 eV) fraction and a high-energy (11-35 eV) one, the both factions having similar electron density. Clear splitting was observed during the RMP pulse in the low-field-side scrape-off-layer profiles of the floating potential U fl and the ion saturation current density J sat; these two quantities were obtained both by direct continuous measurement and by evaluation of the IV characteristics of probes with swept bias. The negative peaks of U fl induced by RMP spatially overlaps with the local minima of J sat (and n e) rather than with its local maxima which is partly caused by the spatial variation of the plasma potential and partly by the changed shape of the EEDF. The effective temperature of the whole EEDF is not correlated with the negative peaks of U fl, and the profile of the parallel power flux density shows secondary maxima due to RMP which mimic those of J sat.

  13. Inter- and intra-rater reproducibility of semiautomatic determination of volume parameters in cardiac magnetic resonance imaging

    International Nuclear Information System (INIS)

    Trieb, Thomas; Glodny, Bernhard; Scheiblhofer, Martin; Wolf, Christian; Metzler, Bernhard; Pachinger, Otmar; Jaschke, Werner R.; Schocke, Michael F.H.

    2008-01-01

    Purpose: The purpose of this study was to evaluate inter- and intra-rater reproducibility in volume assessment using cardiac magnetic resonance imaging (CMRI). Methods: Twenty-five healthy volunteers and 106 patients were included into this retrospective study and received CMRI. The patients were divided in three groups (group I, 80 patients with arrhythmia; group II, 20 patients with cardiomyopathy; group III, 6 patients after correction of septum defects). Therefore, the images were semiautomatically segmented by an experienced and an unexperienced radiologists. The analysis of end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV) as well as ejection fraction (EF) and myocardial mass (MM) were performed twice by an experienced and an unexperienced radiologists. The intra-class correlation coefficients (ICC) were determined for the evaluation of inter- and intra-rater variance. Results: The intra-rater reproducibility for determination of EF, ESV, EDV and MM was excellent with ICCs ranging from 0.88 to 0.99 (all p < 0.001). The inter-observer reproducibility for these parameters was also excellent with ICCs ranging from 0.91 to 0.98 (all p < 0.001). The assessment of the SV showed an excellent intra-rater agreement with ICCs of 0.96 and 0.92 (both p < 0.001), but only a moderate ICC for the inter-rater reproducibility (0.54, p < 0.001). Conclusions: Our study shows that assessment of cardiac volumes can be performed on CMRIs with an excellent reproducibility by both experienced and unexperienced investigators

  14. CHANGE OF CONNECTION BETWEEN MAGNETIC PARAMETERS OF CAST IRON IN COMPARISON WITH STEEL UNDER INFLUENCE OF INTERNAL DEMAGNETIZATION

    Directory of Open Access Journals (Sweden)

    S. G. Sandomirsky

    2014-01-01

    Full Text Available Connection of maximum magnetic permeability µm of cast irons with coercive force Нс and residual magnetism Мr is established in all size of changing of the magnetic characteristics of cast iron. Differences of this connection for steels and cast irons are revealed. Formula for calculation µm of steels by Нс and Мr is corrected for calculation µm of cast irons. As a result of correction the calculation error of cast irons µm is diminished. The results can be used in magnetic structural analysis instead of labor-consuming measurement µm.

  15. Modeling of Toxicity-Relevant Electrophilic Reactivity for Guanine with Epoxides: Estimating the Hard and Soft Acids and Bases (HSAB) Parameter as a Predictor.

    Science.gov (United States)

    Zhang, Jing; Wang, Chenchen; Ji, Li; Liu, Weiping

    2016-05-16

    According to the electrophilic theory in toxicology, many chemical carcinogens in the environment and/or their active metabolites are electrophiles that exert their effects by forming covalent bonds with nucleophilic DNA centers. The theory of hard and soft acids and bases (HSAB), which states that a toxic electrophile reacts preferentially with a biological macromolecule that has a similar hardness or softness, clarifies the underlying chemistry involved in this critical event. Epoxides are hard electrophiles that are produced endogenously by the enzymatic oxidation of parent chemicals (e.g., alkenes and PAHs). Epoxide ring opening proceeds through a SN2-type mechanism with hard nucleophile DNA sites as the major facilitators of toxic effects. Thus, the quantitative prediction of chemical reactivity would enable a predictive assessment of the molecular potential to exert electrophile-mediated toxicity. In this study, we calculated the activation energies for reactions between epoxides and the guanine N7 site for a diverse set of epoxides, including aliphatic epoxides, substituted styrene oxides, and PAH epoxides, using a state-of-the-art density functional theory (DFT) method. It is worth noting that these activation energies for diverse epoxides can be further predicted by quantum chemically calculated nucleophilic indices from HSAB theory, which is a less computationally demanding method than the exacting procedure for locating the transition state. More importantly, the good qualitative/quantitative correlations between the chemical reactivity of epoxides and their bioactivity suggest that the developed model based on HSAB theory may aid in the predictive hazard evaluation of epoxides, enabling the early identification of mutagenicity/carcinogenicity-relevant SN2 reactivity.

  16. Magnitude of localized magnetic moments in metals

    International Nuclear Information System (INIS)

    Kiwi, M.; Pestana, E.; Ramirez, R.

    1979-01-01

    The magnitude of the localized magnetic moment of a transition or rare earth element impurity in a metal is evaluated within the framework of the Anderson model. Rotational invariance is preserved throughout. Graphs of the magnitude of the magnetization as a function of the relevant parameters of the model are provided and discussed. (author)

  17. Studying the Relationship between High-Latitude Geomagnetic Activity and Parameters of Interplanetary Magnetic Clouds with the Use of Artificial Neural Networks

    Science.gov (United States)

    Barkhatov, N. A.; Revunov, S. E.; Vorobjev, V. G.; Yagodkina, O. I.

    2018-03-01

    The cause-and-effect relations of the dynamics of high-latitude geomagnetic activity (in terms of the AL index) and the type of the magnetic cloud of the solar wind are studied with the use of artificial neural networks. A recurrent neural network model has been created based on the search for the optimal physically coupled input and output parameters characterizing the action of a plasma flux belonging to a certain magnetic cloud type on the magnetosphere. It has been shown that, with IMF components as input parameters of neural networks with allowance for a 90-min prehistory, it is possible to retrieve the AL sequence with an accuracy to 80%. The successful retrieval of the AL dynamics by the used data indicates the presence of a close nonlinear connection of the AL index with cloud parameters. The created neural network models can be applied with high efficiency to retrieve the AL index, both in periods of isolated magnetospheric substorms and in periods of the interaction between the Earth's magnetosphere and magnetic clouds of different types. The developed model of AL index retrieval can be used to detect magnetic clouds.

  18. The impact of processing parameters on the properties of Zn-bonded Nd-Fe-B magnets

    Science.gov (United States)

    Kelhar, Luka; Zavašnik, Janez; McGuiness, Paul; Kobe, Spomenka

    2016-12-01

    We report on the effect of loading factor and pressure on the density and the magnetic properties of Zn-bonded Nd-Fe-B magnets produced by pulsed-electric-current sintering (PECS). The idea behind this study is to fabricate bonded magnets with a metallic binder in order for the bonded magnet to operate at temperatures higher than 180 °C: the current upper-limit for polymer-bonded magnets. These composites are made of hard-magnetic powder in the form of melt-spun ribbons bonded with the low-melting-point metal Zn. The binder additions were varied from 10 to 30 wt%, and pressures of 50 and 500 MPa were applied. The high-pressure mode with 20 wt% Zn resulted in a 24% increase of Jr, compared to the low-pressure mode. The magnetic measurements revealed a maximum remanence of 0.64 T for 10 wt% Zn, while the coercivity is largely unaffected by the processing conditions. The density of the composites was up to 7.0 g/cm3, corresponding to 94% of the theoretical density. Compared to commercial polymer-bonded magnets, the Zn-bonded counterparts exhibit a slightly lower Jr, but the coercivity is retained. We show that there is a minor diffusion of Zn into the Nd-Fe-B, forming a 1 μm thin transition layer, but it does not harm the magnetic properties. These metal-bonded Nd-Fe-B magnets are ideal for use in high-temperature automotive applications like under-the-hood sensors and other magnet-based devices that are close to the engine.

  19. Biomonitoring polycyclic aromatic hydrocarbons by Salix matsudana leaves: A comparison with the relevant air content and evaluation of environmental parameter effects

    Science.gov (United States)

    Zhao, Xiangai; He, Miao; Shang, Haibo; Yu, Hongling; Wang, Hao; Li, Huijie; Piao, Jingyi; Quinto, Maurizio; Li, Donghao

    2018-05-01

    Studies on seasonal distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) in Salix matsudana leaves covering its annual life cycle were carried out in order to evaluate plant leaf response sensitivity to air pollution. Salix matsudana leaves were collected throughout different development phases of plant leaf inclusive of bud break to fallen leaves, covering from spring (May) to autumn (November). Simultaneously, particle and gas samples were collected using a high volume air sampler. Seven different PAHs were determined simultaneously in these samples. The temperature dependence of the partitioning of PAHs in air and plant leaves was investigated and the results were incorporated into a mathematical model. The measured plant/air partition coefficients have been found to be exponentially proportional to the reciprocal temperature, in agreement with theoretical expectations. Furthermore, in order to define the influence of different parameters on PAH adsorption on plant leaves, area and lipid leaf content were also measured. Results demonstrated that temperature plays a very important role in PAHs partitioning and that this value should be carefully considered during sampling, in order to obtain the best correlation between PAHs concentration in air and leaves.

  20. The impact of processing parameters on the properties of Zn-bonded Nd–Fe–B magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kelhar, Luka, E-mail: luka.kelhar@ijs.si [Department for Nanostructured Materials, Jožef Stefan Institute, Jamova cesta 39, Ljubljana 1000 (Slovenia); Zavašnik, Janez [Centre for Electron Microscopy and Microanalysis (CEMM), Jamova cesta 39, Ljubljana 1000 (Slovenia); McGuiness, Paul; Kobe, Spomenka [Department for Nanostructured Materials, Jožef Stefan Institute, Jamova cesta 39, Ljubljana 1000 (Slovenia); Jožef Stefan International Postgraduate School, Jamova cesta 39, Ljubljana 1000 (Slovenia)

    2016-12-01

    We report on the effect of loading factor and pressure on the density and the magnetic properties of Zn-bonded Nd–Fe–B magnets produced by pulsed-electric-current sintering (PECS). The idea behind this study is to fabricate bonded magnets with a metallic binder in order for the bonded magnet to operate at temperatures higher than 180 °C: the current upper-limit for polymer-bonded magnets. These composites are made of hard-magnetic powder in the form of melt-spun ribbons bonded with the low-melting-point metal Zn. The binder additions were varied from 10 to 30 wt%, and pressures of 50 and 500 MPa were applied. The high-pressure mode with 20 wt% Zn resulted in a 24% increase of J{sub r}, compared to the low-pressure mode. The magnetic measurements revealed a maximum remanence of 0.64 T for 10 wt% Zn, while the coercivity is largely unaffected by the processing conditions. The density of the composites was up to 7.0 g/cm{sup 3}, corresponding to 94% of the theoretical density. Compared to commercial polymer-bonded magnets, the Zn-bonded counterparts exhibit a slightly lower J{sub r}, but the coercivity is retained. We show that there is a minor diffusion of Zn into the Nd–Fe–B, forming a 1 μm thin transition layer, but it does not harm the magnetic properties. These metal-bonded Nd–Fe–B magnets are ideal for use in high-temperature automotive applications like under-the-hood sensors and other magnet-based devices that are close to the engine. - Highlights: • Fabrication of Zn-bonded Nd–Fe–B magnets by pulsed electric current sintering. • Interesting for automotive applications with temperature exceeding 180 °C. • Variations of pressure and loading factor result in higher density and remanence. • Minor diffusion of Zn binder into the MQP-B ribbons is revealed, but does not decrease the magnetic properties. • More stable magnetic properties at high-temperature due to metallic Zn-binder.

  1. Modeling of magnetic fields on a cylindrical surface and associated parameter estimation for development of a size sensor

    International Nuclear Information System (INIS)

    Zhang, Song; Rajamani, Rajesh

    2016-01-01

    This paper develops analytical sensing principles for estimation of circumferential size of a cylindrical surface using magnetic sensors. An electromagnet and magnetic sensors are used on a wearable band for measurement of leg size. In order to enable robust size estimation during rough real-world use of the wearable band, three estimation algorithms are developed based on models of the magnetic field variation over a cylindrical surface. The magnetic field models developed include those for a dipole and for a uniformly magnetized cylinder. The estimation algorithms used include a linear regression equation, an extended Kalman filter and an unscented Kalman filter. Experimental laboratory tests show that the size sensor in general performs accurately, yielding sub-millimeter estimation errors. The unscented Kalman filter yields the best performance that is robust to bias and misalignment errors. The size sensor developed herein can be used for monitoring swelling due to fluid accumulation in the lower leg and a number of other biomedical applications. (paper)

  2. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

  3. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet was energised at the beginning of March 2012 at a low current to check all the MSS safety chains. Then the magnet was ramped up to 3.8 T on 6 March 2012. Unfortunately two days later an unintentional switch OFF of the power converter caused a slow dump. This was due to a misunderstanding of the CCC (CERN Control Centre) concerning the procedure to apply for the CMS converter control according to the beam-mode status at that time. Following this event, the third one since 2009, a discussion was initiated to define possible improvement, not only on software and procedures in the CCC, but also to evaluate the possibility to upgrade the CMS hardware to prevent such discharge from occurring because of incorrect procedure implementations. The magnet operation itself was smooth, and no power cuts took place. As a result, the number of magnetic cycles was reduced to the minimum, with only two full magnetic cycles from 0 T to 3.8 T. Nevertheless the magnet suffered four stops of the cryogeni...

  4. The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety

    International Nuclear Information System (INIS)

    Recoskie, Bryan J; Chronik, Blaine A; Scholl, Timothy J

    2009-01-01

    Peripheral nerve stimulation (PNS) resulting from electric fields induced from the rapidly changing magnetic fields of gradient coils is a concern in MRI. Nerves exposed to either electric fields or changing magnetic fields would be expected to display consistent threshold characteristics, motivating the direct application of electric field exposure criteria from the literature to guide the development of gradient magnetic field exposure criteria for MRI. The consistency of electric and magnetic field exposures was tested by comparing chronaxie times for electric and magnetic PNS curves for 22 healthy human subjects. Electric and magnetic stimulation thresholds were measured for exposure of the forearm using both surface electrodes and a figure-eight magnetic coil, respectively. The average chronaxie times for the electric and magnetic field conditions were 109 ± 11 μs and 651 ± 53 μs (±SE), respectively. We do not propose that these results call into question the basic mechanism, namely that rapidly switched gradient magnetic fields induce electric fields in human tissues, resulting in PNS. However, this result does motivate us to suggest that special care must be taken when using electric field exposure data from the literature to set gradient coil PNS safety standards in MRI.

  5. The relation between lattice parameters of NaCl type U, Np and Pu compounds and their magnetic and binding properties

    International Nuclear Information System (INIS)

    Ohmichi, Toshihiko; Arai, Yasuo

    1992-01-01

    The lattice parameters of NaCl type uranium, neptunium and plutonium compounds are analyzed using Pauling equation. The numbers of bonding electrons and localized electrons of the compounds are calculated using the single bond radius by Pauling for metalloids and assumed ones for the actinides. The number of bonding electrons per unit bonding length can be correlated linearly with the uranium compounds. The number of localized electrons is found to have a speculative relation with magnetic properties, in particular magnetic moments in ordered state; excluding some compounds, the magnetic moments increase at a gradient of 45 degrees with increasing localized electrons in the range up to about 2.5 and then decrease to zero value roughly at a same gradient with increasing localized electrons. (author)

  6. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  7. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  8. Three dimensional numerical study of different parameters effect on the external magnetic field applied to center the arc of the horizontal mercury discharge lamp

    Directory of Open Access Journals (Sweden)

    Mohamed Bechir Ben Hamida

    2015-10-01

    Full Text Available The aim of this paper is to evaluate the magnitude of the external magnetic field to be applied to a horizontal mercury discharge lamp such that the Lorentz forces counterbalance buoyancy forces and the hot region of the arc remains centered inside the lamp with the variation of six parameters of the lamp such as the external temperature of the lamp, envelope thickness, convective loss, Interelectrodeslength, pressure and current supply pointing to the influence of the parameters to the compensating magnetic field value. To achieve this objective, a commercial numerical software “Comsol Multiphysics” is used to implement the model that solves the equations of mass, energy and momentum for laminar compressible flow combined with the Laplace equation for the plasma in a three dimensional.

  9. Perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging in patients with rectal cancer: Correlation with microvascular density and vascular endothelial growth factor expression

    International Nuclear Information System (INIS)

    Kim, Yeo Eun; Lim, Joon Seok; Kim, Myeong Jin; Kim, Ki Whang; Choi, Jun Jeong; Kim, Dae Hong; Myoung, Sung Min

    2013-01-01

    To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer (K trans ) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters (K trans , Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p 0.662 for K trans ; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p 0.741 for K trans ; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). DCE-MRI perfusion parameters, K trans and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.

  10. On massive vector bosons and Abelian magnetic monopoles in D = (3 + 1): a possible way to quantize the topological mass parameter

    International Nuclear Information System (INIS)

    Moura-Melo, Winder A.; Panza, N.; Helayel Neto, J.A.

    1998-12-01

    An Abelian gauge model, with vector and 2-form potential; fields linked by a topological mass term that mixes the two Abelian factors, is shown to exhibit Dirac-like magnetic monopoles in the presence of a matter background. In addition, considering a 'non-minimal coupling' between the fermions and the tensor fields, we obtain a generalized quantisation condition that involves, among others, the mass parameter. Also, it is explicitly shown that 1 loop (finite) corrections do no shift the value of such a mass parameter. (author)

  11. On massive vector bosons and Abelian magnetic monopoles in D = (3 + 1): a possible way to quantize the topological mass parameter

    Energy Technology Data Exchange (ETDEWEB)

    Moura-Melo, Winder A.; Panza, N.; Helayel Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1998-12-01

    An Abelian gauge model, with vector and 2-form potential; fields linked by a topological mass term that mixes the two Abelian factors, is shown to exhibit Dirac-like magnetic monopoles in the presence of a matter background. In addition, considering a 'non-minimal coupling' between the fermions and the tensor fields, we obtain a generalized quantisation condition that involves, among others, the mass parameter. Also, it is explicitly shown that 1{sub loop} (finite) corrections do no shift the value of such a mass parameter. (author)

  12. Coexistence of superconductivity and magnetism in Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2}. Universal suppression of the magnetic order parameter in 122 iron pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Materne, Philipp; Kamusella, Sirko; Sarkar, Rajib; Klauss, Hans-Henning [IFP, TU Dresden, 01062 Dresden (Germany); Harnagea, Luminita [IFW Dresden, Postfach 270016, 01171 Dresden (Germany); Wurmehl, Sabine; Buechner, Bernd [IFP, TU Dresden, 01062 Dresden (Germany); IFW Dresden, Postfach 270016, 01171 Dresden (Germany); Luetkens, Hubertus [PSI, 5232 Villigen (Switzerland); Timm, Carsten [ITP, TU Dresden, 01062 Dresden (Germany)

    2016-07-01

    We examined Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} single crystals with x=0.00, 0.35, 0.50, and 0.67 by means of muon spin relaxation and Moessbauer spectroscopy to investigate the electronic and structural properties of these compounds. CaFe{sub 2}As{sub 2} is a semimetal, which shows spin density wave order below 167 K. By hole doping via Ca→Na substitution, the magnetic order is suppressed and superconductivity emerges with T{sub c}∼34K at optimal doping including a substitution level region where both phases coexist. We have studied the interplay of order parameters in this coexistence region and found nanoscopic coexistence of both order parameters. This is proven by a reduction of the magnetic order parameter by 7% below the superconducting transition temperature. We present a systematic correlation between the reduction of the magnetic order parameter and the ratio of the transition temperatures, T{sub c}/T{sub N}, for the 122 family of the iron-based superconductors.

  13. A least-squares minimization approach for model parameters estimate by using a new magnetic anomaly formula

    Science.gov (United States)

    Abo-Ezz, E. R.; Essa, K. S.

    2016-04-01

    A new linear least-squares approach is proposed to interpret magnetic anomalies of the buried structures by using a new magnetic anomaly formula. This approach depends on solving different sets of algebraic linear equations in order to invert the depth ( z), amplitude coefficient ( K), and magnetization angle ( θ) of buried structures using magnetic data. The utility and validity of the new proposed approach has been demonstrated through various reliable synthetic data sets with and without noise. In addition, the method has been applied to field data sets from USA and India. The best-fitted anomaly has been delineated by estimating the root-mean squared (rms). Judging satisfaction of this approach is done by comparing the obtained results with other available geological or geophysical information.

  14. Influence of external magnetic field on parameters of surface two-focus spin-wave ferromagnetic lens

    International Nuclear Information System (INIS)

    Reshetnyak, S.A.; Berezhinskij, A.S.

    2012-01-01

    The influence of external magnetic field on refraction of surface spin wave propagating through inhomogeneity created in the form of a lens, that is a biaxial ferromagnet placed into uniaxial ferromagnetic medium, is studied.

  15. Tuning the effective parameters in (Ta/Cu/[Ni/Co]x/Ta) multilayers with perpendicular magnetic anisotropy

    Science.gov (United States)

    Ayareh, Zohreh; Moradi, Mehrdad; Mahmoodi, Saman

    2018-06-01

    In this paper, we report perpendicular magnetic anisotropy (PMA) in a (Ta/Cu/[Ni/Co]x/Ta) multilayers structure. These typical structures usually include a multilayer of ferromagnetic and transition metal thin films. Usually, magnetic anisotropy is characterized by magnetization loops determined by magnetometer or magneto-optical Kerr effect (MOKE). The interface between ferromagnetic and metallic layers plays an important role in magnetic anisotropy evolution from out-of-plane to in-plane in (Ta/Cu/[Ni/Co]/Ta) structure. Obtained results from MOKE and magnetometry of these samples show that they have different easy axes due to change in thickness of Cu as spacer layer and difference in number of repetition of [Ni/Co] stacks.

  16. Mapping of soil erosion and redistribution on two agricultural areas in Czech Republic by using of magnetic parameters.

    Science.gov (United States)

    Kapicka, Ales; Stejskalova, Sarka; Grison, Hana; Petrovsky, Eduard; Jaksik, Ondrej; Kodesova, Radka

    2015-04-01

    Soil erosion is one of the major concerns in sustainability of agricultural systems in different areas. Therefore there is a need to develop suitable innovative indirect methods of soil survey. One of this methods is based on well established differentiation in magnetic signature with depth in soil profile. Magnetic method can be applied in the field as well as in the laboratory on collected soil samples. The aim of this study is to evaluate suitability of magnetic method to assess soil degradation and construct maps of cumulative soil loss due to erosion at two morphologically diverse areas with different soil types. Dominant soil unit in the first locality (Brumovice) is chernozem, which is gradually degraded on slopes to regosols. In the second site (Vidim), the dominant soil unit is luvisol, gradualy transformed to regosol due to erosion. Field measurements of magnetic susceptibility were carried out on regular grid, resulting in 101 data points in Brumovice and 65 in Vidim locality. Mass specific magnetic susceptibility χ and its frequency dependence χFD was used to estimate the significance of SP ferrimagnetic particles of pedogenic origin in top soil horizons. Strong correlation was found between the volume magnetic susceptibility (field measurement) and mass- specific magnetic susceptibility measured in the laboratory (Kapicka et al 2013). Values of magnetic susceptibility are spatially distributed depending on terrain position. Higher values were measured at the flat parts (where the original topsoil horizon remained). The lowest values magnetic susceptibility were obtained on the steep valley sides. Here the original topsoil was eroded and mixed by tillage with the soil substrate (loess). Positive correlation between the organic carbon content and volume magnetic susceptibility (R2= 0.89) was found for chernozem area. The differences between the values of susceptibility in the undisturbed soil profile and the magnetic signal after uniform mixing of the

  17. Magnetization as a critical defining parameter for strand in precision dipole applications implications for field error and F-J stability

    CERN Document Server

    Collings, E W; Lee, E

    2001-01-01

    In hadron accelerators, between low energy particle injection and beam accumulation, the guiding dipoles are ramped at some rate dB/dt. Both at injection and during ramping the static and dynamic magnetizations of the magnet windings introduce multipolar distortions into the beam-line field. Dynamic magnetization, controllable by cable design, is estimated and used to provide a criterion against which to evaluate the allowable magnitude of static (persistent-current) magnetization, M, from a field-quality standpoint. The it is of NbTi and advanced Nb/sub 3/Sn conductors are compared and with regard to the latter the question of flux-jump stability is explored. A magnetization criterion for such stability is presented and compared to experiment. It is noted that since Delta M is proportional to critical current density, J/sub c/, and the strand's effective filament diameter, d/sub eff/, the latter has frequently been specified as a critical parameter, although it will need to be re-specified with every increas...

  18. Models for large superconducting toroidal magnet systems

    International Nuclear Information System (INIS)

    Arendt, F.; Brechna, H.; Erb, J.; Komarek, P.; Krauth, H.; Maurer, W.

    1976-01-01

    Prior to the design of large GJ toroidal magnet systems it is appropriate to procure small scale models, which can simulate their pertinent properties and allow to investigate their relevant phenomena. The important feature of the model is to show under which circumstances the system performance can be extrapolated to large magnets. Based on parameters such as the maximum magnetic field and the current density, the maximum tolerable magneto-mechanical stresses, a simple method of designing model magnets is presented. It is shown how pertinent design parameters are changed when the toroidal dimensions are altered. In addition some conductor cost estimations are given based on reactor power output and wall loading

  19. Effect of laser beam parameters on magnetic properties of Nd-Fe-B thick-film magnets fabricated by pulsed laser deposition

    International Nuclear Information System (INIS)

    Fukunaga, H.; Nakano, M.; Yanai, T.; Kamikawatoko, T.; Yamashita, F.

    2011-01-01

    The effects of varying the laser power and the spot diameter of a laser beam on the magnetic properties, morphology, and deposition rate of Nd-Fe-B thick-film magnets fabricated by pulsed laser deposition (PLD) were investigated. Reducing the laser fluence on the target reduces the remanence and increases the Nd content and consequently the coercivity of the prepared films. The spot size of the laser beam was found to affect the film surface morphology, the deposition rate, and the reproducibility of the magnetic properties of the prepared films. Reducing the spot size reduces the number of droplets and the reproducibility of the magnetic properties and increases the droplet size. Controlling the spot size of the laser beam enabled us to maximize the deposition rate. Consequently, a coercivity of 1210 kA/m and a remanence of 0.51 T were obtained at a deposition rate of 11.8 μm/(h·W). This deposition rate is 30% greater than the highest previously reported deposition rate by PLD.

  20. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

  1. High-Field Accelerator Magnets

    International Nuclear Information System (INIS)

    Rijk, G de

    2014-01-01

    In this lecture an overview is given of the present technology for high field accelerator magnets. We indicate how to get high fields and what are the most important parameters. The available conductors and their limitations are presented followed by the most relevant types of coils and support structures. We conclude by showing a number of recent examples of development magnets which are either pure R&D objects or models for the LHC luminosity upgrade

  2. Zn induced in-gap electronic states in La214 probed by uniform magnetic susceptibility: relevance to the suppression of superconducting T c

    Science.gov (United States)

    Islam, R. S.; Naqib, S. H.

    2018-02-01

    Substitution of isovalent non-magnetic defects, such as Zn, in the CuO2 plane strongly modifies the magnetic properties of strongly electron correlated hole doped cuprate superconductors. The reason for enhanced uniform magnetic susceptibility, χ, in Zn substituted cuprates is debatable. Generally the defect induced magnetic behavior has been analyzed mainly in terms of two somewhat contrasting scenarios. The first one is due to independent localized moments appearing in the vicinity of Zn arising because of the strong electronic/magnetic correlations present in the host compound and the second one is due to transfer of quasiparticle (QP) spectral weight and creation of weakly localized low-energy electronic states associated with each Zn atom in place of an in-plane Cu. If the second scenario is correct, one should expect a direct correspondence between Zn induced suppression of the superconducting transition temperature, T c, and the extent of the enhanced magnetic susceptibility at low temperature. In this case, the low-T enhancement of χ would be due to weakly localized QP states at low energy and these electronic states will be precluded from taking part in Cooper pairing. We explore this second possibility by analyzing the χ(T) data for La2-x Sr x Cu1-y Zn y O4 with different hole contents, p (=x), and Zn concentrations (y) in this paper. The results of our analysis support this scenario.

  3. Influence of pH Adjustment Parameter for Sol-Gel Modification on Structural, Microstructure, and Magnetic Properties of Nanocrystalline Strontium Ferrite.

    Science.gov (United States)

    Azis, Raba'ah Syahidah; Sulaiman, Sakinah; Ibrahim, Idza Riati; Zakaria, Azmi; Hassan, Jumiah; Muda, Nor Nadhirah Che; Nazlan, Rodziah; Saiden, Norlaily M; Fen, Yap Wing; Mustaffa, Muhammad Syazwan; Matori, Khamirul Amin

    2018-05-23

    Synthesis of nanocrystalline strontium ferrite (SrFe 12 O 19 ) via sol-gel is sensitive to its modification parameters. Therefore, in this study, an attempt of regulating the pH as a sol-gel modification parameter during preparation of SrFe 12 O 19 nanoparticles sintered at a low sintering temperature of 900 °C has been presented. The relationship of varying pH (pH 0 to 8) on structural, microstructures, and magnetic behaviors of SrFe 12 O 19 nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning microscope (FESEM), and vibrating sample magnetometer (VSM). Varying the pH of precursor exhibited a strong effect on the sintered density, crystal structure and magnetic properties of the SrFe 12 O 19 nanoparticles. As the pH is 0, the SrFe 12 O 19 produced relatively largest density, saturation magnetization, M s , and coercivity, H c , at a low sintering temperature of 900 °C. The grain size of SrFe 12 O 19 is obtained in the range of 73.6 to 133.3 nm. The porosity of the sample affected the density and the magnetic properties of the SrFe 12 O 19 ferrite. It is suggested that the low-temperature sintered SrFe 12 O 19 at pH 0 displayed M s of 44.19 emu/g and H c of 6403.6 Oe, possessing a significant potential for applying in low-temperature co-fired ceramic permanent magnet.

  4. Classification of high-resolution multi-swath hyperspectral data using Landsat 8 surface reflectance data as a calibration target and a novel histogram based unsupervised classification technique to determine natural classes from biophysically relevant fit parameters

    Science.gov (United States)

    McCann, C.; Repasky, K. S.; Morin, M.; Lawrence, R. L.; Powell, S. L.

    2016-12-01

    Compact, cost-effective, flight-based hyperspectral imaging systems can provide scientifically relevant data over large areas for a variety of applications such as ecosystem studies, precision agriculture, and land management. To fully realize this capability, unsupervised classification techniques based on radiometrically-calibrated data that cluster based on biophysical similarity rather than simply spectral similarity are needed. An automated technique to produce high-resolution, large-area, radiometrically-calibrated hyperspectral data sets based on the Landsat surface reflectance data product as a calibration target was developed and applied to three subsequent years of data covering approximately 1850 hectares. The radiometrically-calibrated data allows inter-comparison of the temporal series. Advantages of the radiometric calibration technique include the need for minimal site access, no ancillary instrumentation, and automated processing. Fitting the reflectance spectra of each pixel using a set of biophysically relevant basis functions reduces the data from 80 spectral bands to 9 parameters providing noise reduction and data compression. Examination of histograms of these parameters allows for determination of natural splitting into biophysical similar clusters. This method creates clusters that are similar in terms of biophysical parameters, not simply spectral proximity. Furthermore, this method can be applied to other data sets, such as urban scenes, by developing other physically meaningful basis functions. The ability to use hyperspectral imaging for a variety of important applications requires the development of data processing techniques that can be automated. The radiometric-calibration combined with the histogram based unsupervised classification technique presented here provide one potential avenue for managing big-data associated with hyperspectral imaging.

  5. Simulation Research of Magnetically-coupled Resonant Wireless Power Transfer System with Single Intermediate Coil Resonator Based on S Parameters Using ANSYS

    Directory of Open Access Journals (Sweden)

    Liu Cheng

    2016-01-01

    Full Text Available ANSYS can be a powerful tool to simulate the process of energy exchange in magnetically-coupled resonant wireless power transfer system. In this work, the MCR-WPT system with single intermediate coil resonator is simulated and researched based on scattering parameters using ANSYS Electromagnetics. The change rule of power transfer efficiency is reflected intuitively through the scattering parameters. A new method of calculating the coupling coefficient is proposed. A cascaded 2-port network model using scattering parameters is adopted to research the efficiency of transmission. By changing the relative position and the number of turns of the intermediate coil, we find some factors affecting the efficiency of transmission. Methods and principles of designing the MCR-WPT system with single intermediate coil resonator are obtained. And these methods have practical value with design and optimization of system efficiency.

  6. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet worked very well at 3.8 T as expected, despite a technical issue that manifested twice in the cryogenics since June. All the other magnet sub-systems worked without flaw. The issue in the cryogenics was with the cold box: it could be observed that the cold box was getting progressively blocked, due to some residual humidity and air accumulating in the first thermal exchanger and in the adsorber at 65 K. This was later confirmed by the analysis during the regeneration phases. An increase in the temperature difference between the helium inlet and outlet across the heat exchanger and a pressure drop increase on the filter of the adsorber were observed. The consequence was a reduction of the helium flow, first compensated by the automatic opening of the regulation valves. But once they were fully opened, the flow and refrigeration power reduced as a consequence. In such a situation, the liquid helium level in the helium Dewar decreased, eventually causing a ramp down of the magnet current and a field...

  7. MAGNET

    CERN Multimedia

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  8. MAGNET

    CERN Multimedia

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  9. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

    The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

  10. Structural and intrinsic magnetic material parameters of Pr3(Fe,Ti)29 and Pr3(Fe,Ti)29Nx

    International Nuclear Information System (INIS)

    Psycharis, V.; Kalogirou, O.; Devlin, E.; Gjoka, M.; Simopoulos, A.; Niarchos, D.

    1996-01-01

    We report the study of the structural and the intrinsic magnetic properties of the Pr member of the newly discovered class of R 3 (Fe,Ti) 29 compounds and its nitride. The X-ray powder diffraction pattern of the alloy is indexed in monoclinic symmetry with lattice parameters a=10.647(1) A, b=8.6014(7) A, c=9.755(1) A and β=96.92(1) and the structure is described in the A2/m space group. Atomic positions and bond lengths are given. Nitrogenation results in a lattice expansion of 6.6% corresponding to ∝4 N atoms per formula unit. The Curie temperature is 392(5) K, and the saturation magnetization, the anisotropy field and the average hyperfine field at room temperature are 135.4 A m 2 /kg, 3.9 and 20.3 T, respectively. A magnetic phase transition is observed at ∝160 K. After nitrogenation the Curie temperature increases to 721(5) K, and the saturation magnetization to 174.8 A m 2 /kg, the anisotropy field 7.2 T and the average hyperfine field 30.1 T at room temperature. Moessbauer spectroscopy, X-ray powder diffraction and magnetization measurements on magnetically oriented powder samples provide evidence of the presence of an easy-cone-type magnetocrystalline anisotropy for both the parent and nitrided compounds in the temperature range 85-300 K. The cone angles calculated from the fitted Moessbauer spectra are 34 for the parent compound and 36 for the nitrided compound. (orig.)

  11. The correlation between acoustic and magnetic properties in the long working metal boiler drum with the parameters of the electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ababkov, Nikolai, E-mail: n.ababkov@rambler.ru; Smirnov, Alexander, E-mail: galvas.kem@gmail.com [T.F. Gorbachev Kuzbass State Technical University, Vesennjaja str 28, Kemerovo, 650000 Russian Federation (Russian Federation)

    2016-01-15

    The present paper presents comparative analysis of measurement results of acoustic and magnetic properties in long working metal of boiler drums and the results obtained by methods of electronic microscopy. The structure of the metal sample from the fracture zone to the base metal (metal working sample long) and the center of the base metal before welding (weld metal sample) was investigated by electron microscopy. Studies performed by spectral acoustic, magnetic noise and electron microscopic methods were conducted on the same plots and the same samples of long working and weld metal of high-pressure boiler drums. The analysis of research results showed high sensitivity of spectral-acoustic and magnetic-noise methods to definition changes of microstructure parameters. Practical application of spectral-acoustic and magnetic noise NDT method is possible for the detection of irregularities and changes in structural and phase state of the long working and weld metal of boiler drums, made of a special molybdenum steel (such as 20M). The above technique can be used to evaluate the structure and physical-mechanical properties of the long working metal of boiler drums in the energy sector.

  12. TWO NOVEL PARAMETERS TO EVALUATE THE GLOBAL COMPLEXITY OF THE SUN'S MAGNETIC FIELD AND TRACK THE SOLAR CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.; Landi, E. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48105 (United States); Gibson, S. E., E-mail: lzh@umich.edu [NCAR/HAO, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

    2013-08-20

    Since the unusually prolonged and weak solar minimum between solar cycles 23 and 24 (2008-2010), the sunspot number is smaller and the overall morphology of the Sun's magnetic field is more complicated (i.e., less of a dipole component and more of a tilted current sheet) compared with the same minimum and ascending phases of the previous cycle. Nearly 13 yr after the last solar maximum ({approx}2000), the monthly sunspot number is currently only at half the highest value of the past cycle's maximum, whereas the polar magnetic field of the Sun is reversing (north pole first). These circumstances make it timely to consider alternatives to the sunspot number for tracking the Sun's magnetic cycle and measuring its complexity. In this study, we introduce two novel parameters, the standard deviation (SD) of the latitude of the heliospheric current sheet (HCS) and the integrated slope (SL) of the HCS, to evaluate the complexity of the Sun's magnetic field and track the solar cycle. SD and SL are obtained from the magnetic synoptic maps calculated by a potential field source surface model. We find that SD and SL are sensitive to the complexity of the HCS: (1) they have low values when the HCS is flat at solar minimum, and high values when the HCS is highly tilted at solar maximum; (2) they respond to the topology of the HCS differently, as a higher SD value indicates that a larger part of the HCS extends to higher latitude, while a higher SL value implies that the HCS is wavier; (3) they are good indicators of magnetically anomalous cycles. Based on the comparison between SD and SL with the normalized sunspot number in the most recent four solar cycles, we find that in 2011 the solar magnetic field had attained a similar complexity as compared to the previous maxima. In addition, in the ascending phase of cycle 24, SD and SL in the northern hemisphere were on the average much greater than in the southern hemisphere, indicating a more tilted and wavier

  13. Evolution of magnetotelluric, total magnetic field, and VLF field parameters in Central Italy. Relations to local seismic activity

    Energy Technology Data Exchange (ETDEWEB)

    Meloni, A.; Di Mauro, D.; Mele, G.; Palangio, P. [Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy); Ernst, T.; Teisseyre, R. [Institute of Geophysics, Warszawa (Poland)

    2001-04-01

    Magnetotelluric data were collected at Collemeluccio (41.72{sup 0}N, 14.37{sup 0}E) in Central Italy from summer 1991 to spring 1998. Analyzed by means of tensor decomposition on the geoelectric potential and robust estimation on the geomagnetic field, this set of data allowed the investigation of the electromagnetic induction, is presented here in its time evolution and compared to local and regional seismic activity. Tecto magnetic field observations from absolute magnetic field level in Central Italy were also made on data simultaneously recorded at four magnetometer stations, using L'Aquila Geomagnetic Observatory as a reference for differentiation. Recent results gathered from a system of two VLF search coil wide-band antennas, installed in the L'Aquila Observatory, are also discussed in relation to local seismic activity.

  14. Experimental simulation of the energy parameters of the "ATLAS" capacitor bank using a disk explosive-magnetic generator

    CERN Document Server

    Buyko, A M; Gorbachev, Yu N; Yegorychev, B T; Zmushko, V V; Ivanov, V A; Ivanova, G G; Kuzaev, A I; Kulagin, A A; Mokhov, V N; Pavlii, V V; Pak, S V; Petrukhin, A A; Skobelev, A N; Sofronov, V N; Chernyshev, V K; Yakubov, V B; Anderson, B G; Atchison, W L; Clark, D A; Faehl, R J; Lindemuth, I R; Reinovsky, R E; Rodrigues, G; Stokes, J L; Tabaka, L J

    2001-01-01

    A joint US/Russian Advanced Liner Technology experiment ALT-1 was conducted to simulate the anticipated performance of the Atlas capacitor bank. A disk-explosive magnetic generator and foil opening switch were used to produce an electrical current waveform that reached a peak value of 32.5 MA and that imploded an aluminum liner to an inner surface velocity of 12 km/s. (6 refs).

  15. BANYAN. IV. Fundamental parameters of low-mass star candidates in nearby young stellar kinematic groups—isochronal age determination using magnetic evolutionary models

    Energy Technology Data Exchange (ETDEWEB)

    Malo, Lison; Doyon, René; Albert, Loïc; Lafrenière, David; Artigau, Étienne; Gagné, Jonathan [Département de physique and Observatoire du Mont-Mégantic, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Feiden, Gregory A. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Riedel, Adric, E-mail: malo@cfht.hawaii.edu, E-mail: doyon@astro.umontreal.ca [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    2014-09-01

    Based on high-resolution optical spectra obtained with ESPaDOnS at Canada-France-Hawaii Telescope, we determine fundamental parameters (T {sub eff}, R, L {sub bol}, log g, and metallicity) for 59 candidate members of nearby young kinematic groups. The candidates were identified through the BANYAN Bayesian inference method of Malo et al., which takes into account the position, proper motion, magnitude, color, radial velocity, and parallax (when available) to establish a membership probability. The derived parameters are compared to Dartmouth magnetic evolutionary models and field stars with the goal of constraining the age of our candidates. We find that, in general, low-mass stars in our sample are more luminous and have inflated radii compared to older stars, a trend expected for pre-main-sequence stars. The Dartmouth magnetic evolutionary models show a good fit to observations of field K and M stars, assuming a magnetic field strength of a few kG, as typically observed for cool stars. Using the low-mass members of the β Pictoris moving group, we have re-examined the age inconsistency problem between lithium depletion age and isochronal age (Hertzspring-Russell diagram). We find that the inclusion of the magnetic field in evolutionary models increases the isochronal age estimates for the K5V-M5V stars. Using these models and field strengths, we derive an average isochronal age between 15 and 28 Myr and we confirm a clear lithium depletion boundary from which an age of 26 ± 3 Myr is derived, consistent with previous age estimates based on this method.

  16. MAGNET

    CERN Multimedia

    Benoit Curé

    The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

  17. MAGNET

    CERN Multimedia

    B. Curé

    During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

  18. Initial experience of correlating parameters of intravoxel incoherent motion and dynamic contrast-enhanced magnetic resonance imaging at 3.0 T in nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Qian-Jun; Zhang, Shui-Xing; Chen, Wen-Bo; Liang, Long; Zhou, Zheng-Gen; Liu, Zai-Yi; Zeng, Qiong-Xin; Liang, Chang-Hong [Guangdong General Hospital/Guangdong Academy of Medical Sciences, Department of Radiology, Guangzhou, Guangdong Province (China); Qiu, Qian-Hui [Guangdong General Hospital/Guangdong Academy of Medical Sciences, Department of Otolaryngology, Guangzhou, Guangdong Province (China)

    2014-12-15

    To determine the correlation between intravoxel incoherent motion (IVIM) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters. Thirty-eight newly diagnosed NPC patients were prospectively enrolled. Diffusion-weighted images (DWI) at 13 b-values were acquired using a 3.0-T MRI system. IVIM parameters including the pure molecular diffusion (D), perfusion-related diffusion (D*), perfusion fraction (f), DCE-MRI parameters including maximum slope of increase (MSI), enhancement amplitude (EA) and enhancement ratio (ER) were calculated by two investigators independently. Intra- and interobserver agreement were evaluated using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Relationships between IVIM and DCE-MRI parameters were evaluated by calculation of Spearman's correlation coefficient. Intra- and interobserver reproducibility were excellent to relatively good (ICC = 0.887-0.997; narrow width of 95 % limits of agreement). The highest correlation was observed between f and EA (r = 0.633, P < 0.001), with a strong correlation between f and MSI (r = 0.598, P = 0.001). No correlation was observed between f and ER (r = -0.162; P = 0.421) or D* and DCE parameters (r = 0.125-0.307; P > 0.119). This study suggests IVIM perfusion imaging using 3.0-T MRI is feasible in NPC, and f correlates significantly with EA and MSI. (orig.)

  19. Multivariate modelling of prostate cancer combining magnetic resonance derived T2, diffusion, dynamic contrast-enhanced and spectroscopic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Riches, S.F.; Payne, G.S.; Morgan, V.A.; DeSouza, N.M. [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, CRUK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Dearnaley, D. [Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Department of Urology and Department of Academic Radiotherapy, Sutton, Surrey (United Kingdom); Morgan, S. [The Ottawa Hospital Cancer Centre and the University of Ottawa, Division of Radiation Oncology, Ottawa, Ontario (Canada); Partridge, M. [The Institute of Cancer Research, Section of Radiotherapy and Imaging, Sutton, Surrey (United Kingdom); University of Oxford, The Gray Institute for Radiation Oncology and Biology, Oxford (United Kingdom); Livni, N. [Royal Marsden NHS Foundation Trust Chelsea, Department of Histopathology, London (United Kingdom); Ogden, C. [Royal Marsden NHS Foundation Trust Chelsea, Department of Urology, London (United Kingdom)

    2015-05-01

    The objectives are determine the optimal combination of MR parameters for discriminating tumour within the prostate using linear discriminant analysis (LDA) and to compare model accuracy with that of an experienced radiologist. Multiparameter MRIs in 24 patients before prostatectomy were acquired. Tumour outlines from whole-mount histology, T{sub 2}-defined peripheral zone (PZ), and central gland (CG) were superimposed onto slice-matched parametric maps. T{sub 2,} Apparent Diffusion Coefficient, initial area under the gadolinium curve, vascular parameters (K{sup trans},K{sub ep},V{sub e}), and (choline+polyamines+creatine)/citrate were compared between tumour and non-tumour tissues. Receiver operating characteristic (ROC) curves determined sensitivity and specificity at spectroscopic voxel resolution and per lesion, and LDA determined the optimal multiparametric model for identifying tumours. Accuracy was compared with an expert observer. Tumours were significantly different from PZ and CG for all parameters (all p < 0.001). Area under the ROC curve for discriminating tumour from non-tumour was significantly greater (p < 0.001) for the multiparametric model than for individual parameters; at 90 % specificity, sensitivity was 41 % (MRSI voxel resolution) and 59 % per lesion. At this specificity, an expert observer achieved 28 % and 49 % sensitivity, respectively. The model was more accurate when parameters from all techniques were included and performed better than an expert observer evaluating these data. (orig.)

  20. Analytic formulae for the Hartree-Fock order parameter at arbitrary p/q filling factors for the 2DEG in a magnetic field

    International Nuclear Information System (INIS)

    Cabo Monte Oca, A. de.

    1994-07-01

    Analytic expressions for order parameters are given for the previously introduced general class of Hartree Fock states at arbitrary filling factors ν=p/q for odd q values. The order parameters are expressed as sums of magnetic translations eigenvalues over the filled single electron states. Simple summation formulae for the band spectra in terms of the same eigenvalues are also presented. The energy per particle at ν=1/3 is calculated for various states differing in the way of filling of the 1/3 of the orbitals. The calculated energies are not competing with the usual CDW results. However the high degree of electron overlapping allows for the next corrections to modify this situation. The discussion suggests these Hartree-Fock Slater determinants as interesting alternatives for the Tao-Thouless parent states which may correct their anomalous symmetry and correlation functions properties. (author). 28 refs

  1. Anisotropy of Anhysteretic Remanenct Magnetization (AARM) and its Dependence on Experimental Parameters - Implications for Fabric Interpretation and Paleomagnetic Corrections

    Science.gov (United States)

    Feinberg, J. M.; Biedermann, A. R.; Bilardello, D.; Jackson, M.

    2017-12-01

    Magnetic fabrics often serve as proxies for mineral fabrics, and anisotropy of remanent magnetization in particular assesses the crystallographic and shape preferred orientation of ferromagnetic (sensu lato) minerals. Anisotropy of anhysteretic remanent magnetization (AARM) is most commonly measured by imparting a set of directional anhysteretic remanences over the entire coercivity range of the sample, or up to the maximum field the (de)magnetizer can reach. However, if several ferromagnetic minerals or grain sizes coexist in a rock, they may be affected by different stress fields or stages of deformation. For example, if magnetite is present both as exsolution lamellae within silicates as well as interstitial grains between silicates, then these two populations may possess significantly different fabrics. In this study, we investigate how AARM in a rock changes when the remanence is imparted over different coercivity windows. For this, remanences are imposed over 0-20, 0-50, 0-100, 0-180, and 20-50, 50-100 and 100-180 mT. We will also investigate how the strength of the DC bias field affects AARM tensors. Preliminary results on rocks from a series of lithologies indicate that principal directions, degree and shape of the ARM anisotropy can vary dramatically across different coercivity windows. The degree of anisotropy can either decrease or increase as higher-coercivity grains are included. In particular, it should be noted that the coercivity fraction carrying the largest portion of the remanence does not necessarily dominate the AARM. Principal directions can be similar for all coercivity windows, but a number of samples show distinct orientations of the 0-20 mT AARM tensors vs the 50-100 or 100-180 mT tensors, with the 0-50, 0-100 and 0-180 mT AARMs being a combination of these two fabrics. Changes in AARM tensors will influence the interpretation of inferred flow or deformation patterns, as well as anisotropy corrections of paleomagnetic data. Therefore

  2. Resonant alteration of propagation in guiding structures with complex Robin parameter and its magnetic-field-induced restoration

    International Nuclear Information System (INIS)

    Olendski, O.

    2011-01-01

    Highlights: → Solutions of the wave equation are analyzed for the confined circular geometry with complex Robin boundary conditions. → Sharp extremum is found in the energy dependence on the imaginary part of the extrapolation length. → Nonzero real part of the Robin length or/and magnetic field wipe out the resonance. - Abstract: Solutions of the scalar Helmholtz wave equation are derived for the analysis of the transport and thermodynamic properties of the two-dimensional disk and three-dimensional infinitely long straight wire in the external uniform longitudinal magnetic field B under the assumption that the Robin boundary condition contains extrapolation length Λ with nonzero imaginary part Λ i . As a result of this complexity, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk characteristic for the real Λ turn into the corresponding quasibound states with their lifetime defined by the eigenenergies imaginary parts E i . Accordingly, the longitudinal flux undergoes an alteration as it flows along the wire with its attenuation/amplification being E i -dependent too. It is shown that, for zero magnetic field, the component E i as a function of the Robin imaginary part exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part Λ r of the extrapolation length. Increasing magnitude of Λ r quenches the E i - Λ i resonance and at very large Λ r the eigenenergies E approach the asymptotic real values independent of Λ i . The extremum is also wiped out by the magnetic field when, for the large B, the energies tend to the Landau levels. Mathematical and physical interpretations of the obtained results are provided; in particular, it is shown that the finite lifetime of the disk quasibound states stems from the Λ i -induced currents flowing through the sample boundary. Possible experimental tests of the calculated effect are discussed; namely

  3. Electronic and magnetic properties of the Co{sub 2}MnAl/Au interface: Relevance of the Heusler alloy termination

    Energy Technology Data Exchange (ETDEWEB)

    Makinistian, L., E-mail: lmakinistian@santafe-conicet.gov.ar [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, 3000 Santa Fe (Argentina); Facultad de Ingeniería, Universidad Nacional de Entre Ríos, 3101 Oro Verde (Argentina); Albanesi, E.A. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, 3000 Santa Fe (Argentina); Facultad de Ingeniería, Universidad Nacional de Entre Ríos, 3101 Oro Verde (Argentina)

    2015-07-01

    We present ab initio calculations of electronic and magnetic properties of the ferromagnetic metal/normal metal (F/N) interface of the Heusler alloy Co{sub 2}MnAl and gold. Two structural models are implemented: one with the ferromagnet slab terminated in a pure cobalt plane (“Co{sub 2}-t”), and the other with it terminated with a plane of MnAl (“MnAl-t”). The relaxed optimum distance between the slabs is determined for the two models before densities of states, magnetic moments, and the electric potential are resolved and analyzed layer by layer through the interface. Complementary, calculations for the free surfaces of gold and the Heusler alloy (for both models, Co{sub 2}-t and MnAl-t) are performed for a better interpretation of the physics of the interface. We predict important differences between the two models, suggesting that both terminations are to be expected to display sensibly different spin injection performances. - Highlights: • Ab initio electronic and magnetic properties of the interface Co{sub 2}MnAl/Au. • Two terminations were studied: Co{sub 2} and MnAl terminated. • The termination of the Heusler alloy sensibly determines the interface properties. • The Co{sub 2} terminated interface displays a higher spin polarization.

  4. Towards a generic procedure for the detection of relevant contaminants from waste electric and electronic equipment (WEEE) in plastic food-contact materials: a review and selection of key parameters.

    Science.gov (United States)

    Puype, Franky; Samsonek, Jiří; Vilímková, Věra; Kopečková, Šárka; Ratiborská, Andrea; Knoop, Jan; Egelkraut-Holtus, Marion; Ortlieb, Markus; Oppermann, Uwe

    2017-10-01

    Recently, traces of brominated flame retardants (BFRs) have been detected in black plastic food-contact materials (FCMs), indicating the presence of recycled plastics, mainly coming from waste electric and electronic equipment (WEEE) as BFRs are one of the main additives in electric applications. In order to evaluate efficiently and preliminary in situ the presence of WEEE in plastic FCMs, a generic procedure for the evaluation of WEEE presence in plastic FCMs by using defined parameters having each an associated importance level has been proposed. This can be achieved by combining parameters like overall bromine (Br) and antimony (Sb) content; additive and reactive BFR, rare earth element (REE) and WEEE-relevant elemental content and additionally polymer purity. In most of the cases, the WEEE contamination could be confirmed by combining X-ray fluorescence (XRF) spectrometry and thermal desorption/pyrolysis gas chromatography-mass spectrometry (GC-MS) at first. The Sb and REE content did not give a full confirmation as to the source of contamination, however for Sb the opposite counts: Sb was joined with elevated Br signals. Therefore, Br at first followed by Sb were used as WEEE precursors as both elements are used as synergetic flame-retardant systems. WEEE-specific REEs could be used for small WEEE (sWEEE) confirmation; however, this parameter should be interpreted with care. The polymer purity by Fourier-transform infrared spectrometer (FTIR) and pyrolysis GC-MS in many cases could not confirm WEEE-specific contamination; however, it can be used for purity measurements and for the suspicion of the usage of recycled fractions (WEEE and non-WEEE) as a third-line confirmation. To the best of our knowledge, the addition of WEEE waste to plastic FCMs is illegal; however, due to lack on screening mechanisms, there is still the breakthrough of such articles onto the market, and, therefore, our generic procedure enables the quick and effective screening of suspicious

  5. Frequency method for determining the parameters of the electromagnetic brakes and slip-type couplings with solid magnetic circuits

    Science.gov (United States)

    Guseynov, F. G.; Abbasova, E. M.

    1977-01-01

    The equivalent representation of brakes and coupling by lumped circuits is investigated. Analytical equations are derived for relating the indices of the transients to the parameters of the equivalent circuits for arbitrary rotor speed. A computer algorithm is given for the calculations.

  6. Cubic Dresselhaus interaction parameter from quantum corrections to the conductivity in the presence of an in-plane magnetic field

    Science.gov (United States)

    Marinescu, D. C.

    2017-09-01

    We evaluate the quantum corrections to the conductivity of a two-dimensional electron system with competing Rashba (R) and linear and cubic Dresselhaus (D) spin-orbit interactions in the presence of an in-plane magnetic field B . Within a perturbative approximation, we investigate the interplay between the spin-orbit coupling and the magnetic field in determining the transport regime in two different limiting scenarios: when only one of the linear terms, either Rashba or Dresselhaus, dominates, and at equal linear couplings, when the cubic Dresselhaus breaks the spin symmetry. In each instance, we find that for B higher than a critical value, the antilocalization correction is suppressed and the effective dephasing time saturates to a constant value determined only by the spin-orbit interaction. At equal R-D linear couplings, this value is directly proportional with the cubic Dresselhaus contribution. In the same regime, the magnetoconductivity is expressed as a simple logarithmic function dependent only on the cubic Dresselhaus constant.

  7. Parameters of glucose metabolism and the aging brain: a magnetization transfer imaging study of brain macro- and micro-structure in older adults without diabetes.

    Science.gov (United States)

    Akintola, Abimbola A; van den Berg, Annette; Altmann-Schneider, Irmhild; Jansen, Steffy W; van Buchem, Mark A; Slagboom, P Eline; Westendorp, Rudi G; van Heemst, Diana; van der Grond, Jeroen

    2015-08-01

    Given the concurrent, escalating epidemic of diabetes mellitus and neurodegenerative diseases, two age-related disorders, we aimed to understand the relation between parameters of glucose metabolism and indices of pathology in the aging brain. From the Leiden Longevity Study, 132 participants (mean age 66 years) underwent a 2-h oral glucose tolerance test to assess glucose tolerance (fasted and area under the curve (AUC) glucose), insulin sensitivity (fasted and AUC insulin and homeostatic model assessment of insulin sensitivity (HOMA-IS)) and insulin secretion (insulinogenic index). 3-T brain MRI was used to detect macro-structural damage (atrophy, white matter hyper-intensities, infarcts and/or micro-bleeds) and magnetization transfer imaging (MTI) to detect loss of micro-structural homogeneity that remains otherwise invisible on conventional MRI. Macro-structurally, higher fasted glucose was significantly associated with white matter atrophy (P = 0.028). Micro-structurally, decreased magnetization transfer ratio (MTR) peak height in gray matter was associated with higher fasted insulin (P = 0.010), AUCinsulin (P = 0.001), insulinogenic index (P = 0.008) and lower HOMA-IS index (P glucose was associated with macro-structural damage, impaired insulin action was associated more strongly with reduced micro-structural brain parenchymal homogeneity. These findings offer some insight into the association between different parameters of glucose metabolism (impairment of which is characteristic of diabetes mellitus) and brain aging.

  8. Magnetic

    Science.gov (United States)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  9. MAGNET

    CERN Multimedia

    Benoit Curé

    2013-01-01

    Maintenance work and consolidation activities on the magnet cryogenics and its power distribution are progressing according to the schedules. The manufacturing of the two new helium compressor frame units has started. The frame units support the valves, all the sensors and the compressors with their motors. This activity is subcontracted. The final installation and the commissioning at CERN are scheduled for March–April 2014. The overhauls of existing cryogenics equipment (compressors, motors) are in progress. The reassembly of the components shall start in early 2014. The helium drier, to be installed on the high-pressure helium piping, has been ordered and will be delivered in the first trimester of 2014. The power distribution for the helium compressors in SH5 on the 3.3kV network is progressing. The 3.3kV switches, between each compressor and its hot spare compressor, are being installed, together with the power cables for the new compressors. The 3.3kV electrical switchboards in SE5 will ...

  10. Variation of intrinsic magnetic parameters of single domain Co-N interstitial nitrides synthesized via hexa-ammine cobalt nitrate route

    Energy Technology Data Exchange (ETDEWEB)

    Ningthoujam, R.S. [Department of Chemistry, Indian Institute of Technology, Kanpur 208016 (India); Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Panda, R.N., E-mail: rnp@bits-goa.ac.in [Chemistry Group, Birla Institute of Technology and Science-Pilani, Goa Campus, Zuari Nagar, Goa 403726 (India); Gajbhiye, N.S. [Department of Chemistry, Indian Institute of Technology, Kanpur 208016 (India)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Variation of intrinsic magnetic parameters of Co-N. Black-Right-Pointing-Pointer Synthesis by hexa-ammine cobalt complex route. Black-Right-Pointing-Pointer Tuning of coercivity by variation of size. - Abstract: We report the variation of Curie temperature (T{sub c}) and coercivity (H{sub c}) of the single domain Co-N interstitial materials synthesized via nitridation of the hexa-ammine Cobalt(III) nitrate complex at 673 K. Co-N materials crystallize in the fcc cubic structure with unit cell parameter, a = 3.552 Angstrom-Sign . The X-ray diffraction (XRD) peaks are broader indicating the materials to be nano-structured with crystallite sizes of 5-14 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies confirm the nanocrystalline nature of the materials. TEM images show chain-like clusters indicating dipolar interactions between the particles. Magnetic studies focus on the existence of giant magnetic Co atoms in the Co-N lattice that are not influenced by the thermal relaxation. The values of the H{sub c} could be tuned with the dimension of the particles. The values of T{sub c} of the nitride materials are masked by the onset of the ferromagnetic to superparamagnetic transition at higher temperatures. Thermomagnetic studies show an increasing trend in the Curie temperature, T{sub c}, with decrease in particle dimension. This result has been explained qualitatively on the basis of ferromagnetic to superparamagnetic transition and finite size scaling effects.

  11. Cardiac Magnetic Resonance Imaging in Myocarditis Reveals Persistent Disease Activity Despite Normalization of Cardiac Enzymes and Inflammatory Parameters at 3-Month Follow-Up.

    Science.gov (United States)

    Berg, Jan; Kottwitz, Jan; Baltensperger, Nora; Kissel, Christine K; Lovrinovic, Marina; Mehra, Tarun; Scherff, Frank; Schmied, Christian; Templin, Christian; Lüscher, Thomas F; Heidecker, Bettina; Manka, Robert

    2017-11-01

    There is a major unmet need to identify high-risk patients in myocarditis. Although decreasing cardiac and inflammatory markers are commonly interpreted as resolving myocarditis, this assumption has not been confirmed as of today. We sought to evaluate whether routine laboratory parameters at diagnosis predict dynamic of late gadolinium enhancement (LGE) as persistent LGE has been shown to be a risk marker in myocarditis. Myocarditis was diagnosed based on clinical presentation, high-sensitivity troponin T, and cardiac magnetic resonance imaging, after exclusion of obstructive coronary artery disease by angiography. Cardiac magnetic resonance imaging was repeated at 3 months. LGE extent was analyzed with the software GT Volume. Change in LGE >20% was considered significant. Investigated cardiac and inflammatory markers included high-sensitivity troponin T, creatine kinase, myoglobin, N-terminal B-type natriuretic peptide, C-reactive protein, and leukocyte count. Twenty-four patients were enrolled. Absolute levels of cardiac enzymes and inflammatory markers at baseline did not predict change in LGE at 3 months. Cardiac and inflammatory markers had normalized in 21 patients (88%). LGE significantly improved in 16 patients (67%); however, it persisted to a lesser degree in 17 of them (71%) and increased in a small percentage (21%) despite normalization of cardiac enzymes. This is the first study reporting that cardiac enzymes and inflammatory parameters do not sufficiently reflect LGE in myocarditis. Although a majority of patients with normalizing laboratory markers experienced improved LGE, in a small percentage LGE worsened. These data suggest that cardiac magnetic resonance imaging might add value to currently existing diagnostic tools for risk assessment in myocarditis. © 2017 American Heart Association, Inc.

  12. Development of a dual-energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast-kVp switching dual-energy computed tomography system.

    Science.gov (United States)

    Nute, Jessica L; Jacobsen, Megan C; Stefan, Wolfgang; Wei, Wei; Cody, Dianna D

    2018-04-01

    A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV-switching dual-energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual-energy quality control (DEQC). A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging. Inserts included tissue equivalent and material rods (including iodine and calcium at varying concentrations). The phantom was scanned on a fast kV-switching DECT system using 16 dual-energy acquisitions (CTDIvol range: 10.3-62 mGy) with varying pitch, rotation time, and tube current. The circular head phantom (22 cm diameter) was scanned using a similar protocol (12 acquisitions; CTDIvol range: 36.7-132.6 mGy). All acquisitions were reconstructed at 50, 70, 110, and 140 keV and using a water-iodine material basis pair. The images were evaluated for iodine quantification accuracy, stability of monoenergetic reconstruction CT number, noise, and positional constancy. Variance component analysis was used to identify technique parameters that drove deviations in test metrics. Variances were compared to thresholds derived from manufacturer tolerances to determine technique parameters that had a nominally significant effect on test metrics. Iodine quantification error was largely unaffected by any of the technique parameters investigated. Monoenergetic HU stability was found to be affected by mAs, with a threshold under which spectral separation was unsuccessful, diminishing the utility of DECT imaging. Noise was found to be affected by CTDIvol in the DEQC body phantom, and CTDIvol and mA in the DEQC head phantom. Positional constancy was found to be affected by mAs in the DEQC body phantom and mA in the DEQC head phantom. A streamlined scan protocol

  13. The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection

    International Nuclear Information System (INIS)

    Bamford, R; Bradford, J; Bingham, R; Gargate, L; Hapgood, M; Stamper, R; Gibson, K J; Thornton, A J; Silva, L O; Fonseca, R A; Norberg, C; Todd, T

    2008-01-01

    Here we describe a new experiment to test the shielding concept of a dipole-like magnetic field and plasma, surrounding a spacecraft forming a 'mini magnetosphere'. Initial laboratory experiments have been conducted to determine the effectiveness of a magnetized plasma barrier to be able to expel an impacting, low beta, supersonic flowing energetic plasma representing the solar wind. Optical and Langmuir probe data of the plasma density, the plasma flow velocity and the intensity of the dipole field clearly show the creation of a narrow transport barrier region and diamagnetic cavity virtually devoid of energetic plasma particles. This demonstrates the potential viability of being able to create a small 'hole' in a solar wind plasma, of the order of the ion Larmor orbit width, in which an inhabited spacecraft could reside in relative safety. The experimental results have been quantitatively compared with a 3D particle-in-cell 'hybrid' code simulation that uses kinetic ions and fluid electrons, showing good qualitative agreement and excellent quantitative agreement. Together the results demonstrate the pivotal role of particle kinetics in determining generic plasma transport barriers.

  14. The influence of the low-frequency magnetic fields of different parameters on the secretion of cortisol in men

    Directory of Open Access Journals (Sweden)

    Marta Woldańska-Okońska

    2013-02-01

    Full Text Available Objectives: The aim of this paper is to test the infl uence of long-term application of the low-frequency magnetic fi elds in magnetotherapy and magnetostimulation on cortisol secretion in men. Materials and Methods: Patients were divided into three groups: 16 men underwent magnetotherapy and 20 men (divided into two groups underwent magnetostimulation. Magnetotherapy – 2 mT induction, 40 Hz, bipolar square wave, was applied for 20 min to lumbar area. Magnetostimulation (Viofor Jaroszyk, Paluszak, Sieroń (JPS system, M2P2 program was applied to 10 patients for 12 min each day. The third group (10 patients underwent magnetostimulation (Viofor JPS system, M3P3 for 12 min each day using a different machine. All groups had 15 rounds of applications at approximately 10:00 a.m. with intermissions on the weekends. Blood serum was taken four times in a 24-hour period, before applications, the day after applications and a month later. Chemiluminescence micromethod was used to indicate hormone concentrations. Data was statistically analyzed with the analysis of variance (ANOVA method. Results: The statistically signifi cant gains in the circadian cortisol profi le at 4:00 p.m., before and after application, were observed as a decrease in concentration during magnetotherapy. In magnetostimulation, with the M2P2 program, a signifi cant increase in the cortisol concentration was observed in circadian profi le at 12:00 p.m. one month after the last application. After magnetostimulation with the M3P3 program, a signifi cant increase in concentration at 6:00 a.m. and a decrease in concentration at 12:00 p.m. were observed one month later. Statistically signifi cant difference was demonstrated in the participants after the application of magnetotherapy and magnetostimulation with M3P3 program compared to the men submitted to magnetostimulation, with M2P2 program, at 4:00 p.m. after 15 applications. Conclusions: Biological hysteresis one month after

  15. The influence of the low-frequency magnetic fields of different parameters on the secretion of cortisol in men.

    Science.gov (United States)

    Woldańska-Okońska, Marta; Czernicki, Jan; Karasek, Michał

    2013-03-01

    The aim of this paper is to test the influence of long-term application of the low-frequency magnetic fields in magnetotherapy and magnetostimulation on cortisol secretion in men. Patients were divided into three groups: 16 men underwent magnetotherapy and 20 men (divided into two groups) underwent magnetostimulation. Magnetotherapy - 2 mT induction, 40 Hz, bipolar square wave, was applied for 20 min to lumbar area. Magnetostimulation (Viofor Jaroszyk, Paluszak, Sieroń (JPS) system, M2P2 program) was applied to 10 patients for 12 min each day. The third group (10 patients) underwent magnetostimulation (Viofor JPS system, M3P3) for 12 min each day using a different machine. All groups had 15 rounds of applications at approximately 10:00 a.m. with intermissions on the weekends. Blood serum was taken four times in a 24-hour period, before applications, the day after applications and a month later. Chemiluminescence micromethod was used to indicate hormone concentrations. Data was statistically analyzed with the analysis of variance (ANOVA) method. The statistically significant gains in the circadian cortisol profile at 4:00 p.m., be- fore and after application, were observed as a decrease in concentration during magnetotherapy. In magnetostimulation, with the M2P2 program, a significant increase in the cortisol concentration was observed in circadian profile at 12:00 p.m. one month after the last application. After magnetostimulation with the M3P3 program, a significant increase in concentration at 6:00 a.m. and a decrease in concentration at 12:00 p.m. were observed one month later. Statistically significant difference was demonstrated in the participants after the application of magnetotherapy and magnetostimulation with M3P3 program compared to the men submitted to magnetostimulation, with M2P2 program, at 4:00 p.m. after 15 applications. Biological hysteresis one month after magnetostimulation suggests long-term influence on the hypothalamo-hypophysial axis. The

  16. Clinical relevance and indications for cardiac magnetic resonance imaging 2013. An interdisciplinary expert statement; Klinischer Stellenwert und Indikationen zur Magnetresonanztomografie des Herzens 2013. Ein interdisziplinaeres Expertenstatement

    Energy Technology Data Exchange (ETDEWEB)

    Hergan, Klaus [Universitaetsklinikum Salzburg (Austria). Universitaetsinst. fuer Radiologie; Globits, S. [Herz-Kreislauf-Zentrum Gross Gerungs (Austria); Schuchlenz, H. [Landeskrankenhaus Graz-West (Austria). Dept. fuer Kardiologie/Intensivmedizin] [and others

    2013-03-15

    During the last years the indications of Cardiac Magnetic Resonance Imaging (CMRI) have been continuously expanded. However, the acceptance of the method by cardiologists and radiologists does not correlate with respect to the diagnostic potential. Several factors, such as expensive equipment, relatively long examination times, high technical know how and lack of remuneration, limit the application of CMRI in everyday clinical practice. Furthermore, doctors tend to apply more conventional, well established diagnostic procedures, the access to the method is still limited and there exist difficulties in the interdisciplinary collaboration. The interdisciplinary Austrian approach to Cardiac Imaging is aimed to improve the aforementioned problems and to support the implementation of CMRI in the diagnostic tree of cardiac diseases thus enabling a cost efficient management of patients in cardiology. (orig.)

  17. Definition of pertinent parameters for the evaluation of articular cartilage repair tissue with high-resolution magnetic resonance imaging

    International Nuclear Information System (INIS)

    Marlovits, Stefan; Striessnig, Gabriele; Resinger, Christoph T.; Aldrian, Silke M.; Vecsei, Vilmos; Imhof, Herwig; Trattnig, Siegfried

    2004-01-01

    To evaluate articular cartilage repair tissue after biological cartilage repair, we propose a new technique of non-invasive, high-resolution magnetic resonance imaging (MRI) and define a new classification system. For the definition of pertinent variables the repair tissue of 45 patients treated with three different techniques for cartilage repair (microfracture, autologous osteochondral transplantation, and autologous chondrocyte transplantation) was analyzed 6 and 12 months after the procedure. High-resolution imaging was obtained with a surface phased array coil placed over the knee compartment of interest and adapted sequences were used on a 1 T MRI scanner. The analysis of the repair tissue included the definition and rating of nine pertinent variables: the degree of filling of the defect, the integration to the border zone, the description of the surface and structure, the signal intensity, the status of the subchondral lamina and subchondral bone, the appearance of adhesions and the presence of synovitis. High-resolution MRI, using a surface phased array coil and specific sequences, can be used on every standard 1 or 1.5 T MRI scanner according to the in-house standard protocols for knee imaging in patients who have had cartilage repair procedures without substantially prolonging the total imaging time. The new classification and grading system allows a subtle description and suitable assessment of the articular cartilage repair tissue

  18. Monitoring Tumor Response to Carbogen Breathing by Oxygen-Sensitive Magnetic Resonance Parameters to Predict the Outcome of Radiation Therapy: A Preclinical Study

    Energy Technology Data Exchange (ETDEWEB)

    Cao-Pham, Thanh-Trang; Tran, Ly-Binh-An; Colliez, Florence; Joudiou, Nicolas [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium); El Bachiri, Sabrina [Université Catholique de Louvain, IMMAQ Technological Platform, Methodology and Statistical Support, Louvain-la-Neuve (Belgium); Grégoire, Vincent [Université Catholique de Louvain, Institute of Experimental and Clinical Research, Center for Molecular Imaging, Radiotherapy and Oncology, Brussels (Belgium); Levêque, Philippe; Gallez, Bernard [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium); Jordan, Bénédicte F., E-mail: benedicte.jordan@uclouvain.be [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium)

    2016-09-01

    Purpose: In an effort to develop noninvasive in vivo methods for mapping tumor oxygenation, magnetic resonance (MR)-derived parameters are being considered, including global R{sub 1}, water R{sub 1}, lipids R{sub 1}, and R{sub 2}*. R{sub 1} is sensitive to dissolved molecular oxygen, whereas R{sub 2}* is sensitive to blood oxygenation, detecting changes in dHb. This work compares global R{sub 1}, water R{sub 1}, lipids R{sub 1}, and R{sub 2}* with pO{sub 2} assessed by electron paramagnetic resonance (EPR) oximetry, as potential markers of the outcome of radiation therapy (RT). Methods and Materials: R{sub 1}, R{sub 2}*, and EPR were performed on rhabdomyosarcoma and 9L-glioma tumor models, under air and carbogen breathing conditions (95% O{sub 2}, 5% CO{sub 2}). Because the models demonstrated different radiosensitivity properties toward carbogen, a growth delay (GD) assay was performed on the rhabdomyosarcoma model and a tumor control dose 50% (TCD50) was performed on the 9L-glioma model. Results: Magnetic resonance imaging oxygen-sensitive parameters detected the positive changes in oxygenation induced by carbogen within tumors. No consistent correlation was seen throughout the study between MR parameters and pO{sub 2}. Global and lipids R{sub 1} were found to be correlated to pO{sub 2} in the rhabdomyosarcoma model, whereas R{sub 2}* was found to be inversely correlated to pO{sub 2} in the 9L-glioma model (P=.05 and .03). Carbogen increased the TCD50 of 9L-glioma but did not increase the GD of rhabdomyosarcoma. Only R{sub 2}* was predictive (P<.05) for the curability of 9L-glioma at 40 Gy, a dose that showed a difference in response to RT between carbogen and air-breathing groups. {sup 18}F-FAZA positron emission tomography imaging has been shown to be a predictive marker under the same conditions. Conclusion: This work illustrates the sensitivity of oxygen-sensitive R{sub 1} and R{sub 2}* parameters to changes in tumor oxygenation. However, R{sub 1

  19. Monitoring Tumor Response to Carbogen Breathing by Oxygen-Sensitive Magnetic Resonance Parameters to Predict the Outcome of Radiation Therapy: A Preclinical Study

    International Nuclear Information System (INIS)

    Cao-Pham, Thanh-Trang; Tran, Ly-Binh-An; Colliez, Florence; Joudiou, Nicolas; El Bachiri, Sabrina; Grégoire, Vincent; Levêque, Philippe; Gallez, Bernard; Jordan, Bénédicte F.

    2016-01-01

    Purpose: In an effort to develop noninvasive in vivo methods for mapping tumor oxygenation, magnetic resonance (MR)-derived parameters are being considered, including global R_1, water R_1, lipids R_1, and R_2*. R_1 is sensitive to dissolved molecular oxygen, whereas R_2* is sensitive to blood oxygenation, detecting changes in dHb. This work compares global R_1, water R_1, lipids R_1, and R_2* with pO_2 assessed by electron paramagnetic resonance (EPR) oximetry, as potential markers of the outcome of radiation therapy (RT). Methods and Materials: R_1, R_2*, and EPR were performed on rhabdomyosarcoma and 9L-glioma tumor models, under air and carbogen breathing conditions (95% O_2, 5% CO_2). Because the models demonstrated different radiosensitivity properties toward carbogen, a growth delay (GD) assay was performed on the rhabdomyosarcoma model and a tumor control dose 50% (TCD50) was performed on the 9L-glioma model. Results: Magnetic resonance imaging oxygen-sensitive parameters detected the positive changes in oxygenation induced by carbogen within tumors. No consistent correlation was seen throughout the study between MR parameters and pO_2. Global and lipids R_1 were found to be correlated to pO_2 in the rhabdomyosarcoma model, whereas R_2* was found to be inversely correlated to pO_2 in the 9L-glioma model (P=.05 and .03). Carbogen increased the TCD50 of 9L-glioma but did not increase the GD of rhabdomyosarcoma. Only R_2* was predictive (P<.05) for the curability of 9L-glioma at 40 Gy, a dose that showed a difference in response to RT between carbogen and air-breathing groups. "1"8F-FAZA positron emission tomography imaging has been shown to be a predictive marker under the same conditions. Conclusion: This work illustrates the sensitivity of oxygen-sensitive R_1 and R_2* parameters to changes in tumor oxygenation. However, R_1 parameters showed limitations in terms of predicting the outcome of RT in the tumor models studied, whereas R_2* was found to be

  20. Benefits of Repetitive Transcranial Magnetic Stimulation (rTMS for Spastic Subjects: Clinical, Functional, and Biomechanical Parameters for Lower Limb and Walking in Five Hemiparetic Patients

    Directory of Open Access Journals (Sweden)

    Luc Terreaux

    2014-01-01

    Full Text Available Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1 Hz and 10 Hz were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle. Results. No change was observed after placebo and 10 Hz protocols. Clinical parameters were not significantly modified after 1 Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in Hmax⁡ /Mmax⁡ and T/Mmax⁡ ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified.

  1. Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning

    Directory of Open Access Journals (Sweden)

    Atefeh Shirvani

    2017-01-01

    Full Text Available Background: In radiation therapy, computed tomography (CT simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality. Materials and Methods: In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head. Results: According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P 4 cm and image fusion quality was <25%. Conclusion: The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle.

  2. 3D study of a bi facial polycrystalline photovoltaic cell under constant magnetic field and determination of the parameters of recombination from internal quantum yield

    International Nuclear Information System (INIS)

    ZOUMA Bernard

    2010-01-01

    The work presented in this thesis deals with the problem of the quality of polycrystalline silicon solar cells. This work has been done on square surface columnar grains of the bi facial solar cell. This study ends in the determination of the quality of bi facial solar cells from their recombination parameters. We propose an useful technique to determine these recombination parameters from the algorithm calculation that is based on the internal quantum efficiency. A set of dimensional approach like the three-dimensional model of the solar cell that allows taking into account the grain size and grain boundaries recombination velocity. The emitter contribution and the terrestrial magnetic field influence are taken into account too. While lighted, the emitter region becomes a recombination zone of the electron from the base region. We have obtained a new exhaustive analytical expression of the internal quantum efficiency. This theoretical efficiency is a function of the recombination parameters and it is used to fit the experimental curves of the internal quantum efficiency versus the wavelength. The results are in a good agreement with the experimental values.(Author) [fr

  3. Benefits of repetitive transcranial magnetic stimulation (rTMS) for spastic subjects: clinical, functional, and biomechanical parameters for lower limb and walking in five hemiparetic patients.

    Science.gov (United States)

    Terreaux, Luc; Gross, Raphael; Leboeuf, Fabien; Desal, Hubert; Hamel, Olivier; Nguyen, Jean Paul; Pérot, Chantal; Buffenoir, Kévin

    2014-01-01

    Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1 Hz and 10 Hz) were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle). Results. No change was observed after placebo and 10 Hz protocols. Clinical parameters were not significantly modified after 1 Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in H max⁡ /M max⁡ and T/M max⁡ ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified.

  4. Tension-free vaginal tape versus lata fascia sling: The importance of transvulvar ultrasound in the assessment of relevant anatomical parameters in treatment of women with stress urinary incontinence

    Directory of Open Access Journals (Sweden)

    Frederico Teixeira Brandt

    2009-01-01

    Full Text Available Objective: To describe the relevance of transvulvar ultrasound in the assessment of anatomical differences induced by the lata fascia sling (LFS and tension-free vaginal tape (TVT procedures. Materials and Methods: Forty women with stress urinary incontinence (SUI, aged 30 to 60 years, have been treated with either LFS (20 patients or TVT (20 patients. The transvulvar ultrasound of the urethrovesical junction (UVJ and proximal urethra (PU has been used as the main investigational tool both pre- and post-operatively. The studied parameters were the vertical (VUVJD and horizontal (HUVJD UVJ distances, the pubourethral distance (PUD and the PU length. Results: The VUVJD did not vary significantly after the LFS surgery (P=0.10. The PUD became shorter (P=0.001 and the HUVJD became shorter only at rest (P=0.03 after the correction by LFS. The TVT procedure has led to shortening of the VUVJ displacement (P=0.0005 and of the PU length (P=0.02. Conclusions: The transvulvar ultrasound was of utmost importance in the demonstration that both the LFS and TVT surgical procedures elongate the PU, even though the LFS technique does it more efficiently. The LFS technique focus more on shortening the PUD and the TVT procedure focus more on the correction of the vertical UVJ displacement.

  5. [Chronic chondromalacia of the patella: comparison of morphological (magnetic resonance) and functional findings (isokinetic parameters) after rehabilitation].

    Science.gov (United States)

    Felicetti, G; Avanza, F; Fiori, M; Brignoli, E; Rovescala, R

    1996-01-01

    The knee is a common site for injuries of the cartilage, capsule and ligament, which calls for the use of noninvasive techniques to assess injury severity properly and to plan adequate rehabilitation. Our study was aimed at comparing MR with isokinetic findings. To this purpose, 40 patients were examined; they were all affected with chondromalacia patellae, grades I-III, previously diagnosed at arthroscopy. Namely, 8 patients had grade I and 32 grades II and III chondromalacia. After MR and isokinetic exams, all patients were submitted to a standardized rehabilitation program. Our results indicate a marked decrease in quadriceps strength, especially in the most severe cases; in less severe cases, recovery was complete at 6 months, while the deficit remained in grades II and III injuries. MR yield was not relevant in 4 of 8 cases, while isokinetic findings were negative in one case. Both methods were positive in the most severe cases. At 6 months, both functional and MR findings were normal in grade I injuries, while some alterations remained in the others.

  6. Parameters of DEMO DN and JET DN

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The paper is an appendix to a study of the reactor relevance of the NET design concept. The latter study examines whether the technologies and design principles proposed for NET can be directly extrapolated to a demonstration (DEMO) reactor. The appendix presents the parameters of the DEMO and NET under the topic headings: power, geometry, plasma, toroidal and poloidal magnetic field coils, first wall engineering, divertor physics, divertor engineering, and blanket. (U.K.)

  7. Inventory parameters

    CERN Document Server

    Sharma, Sanjay

    2017-01-01

    This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.

  8. Booster parameter list

    International Nuclear Information System (INIS)

    Parsa, Z.

    1986-10-01

    The AGS Booster is designed to be an intermediate synchrotron injector for the AGS, capable of accelerating protons from 200 MeV to 1.5 GeV. The parameters listed include beam and operational parameters and lattice parameters, as well as parameters pertaining to the accelerator's magnets, vacuum system, radio frequency acceleration system, and the tunnel. 60 refs., 41 figs

  9. The nuclear magnetic moment of 208Bi and its relevance for a test of bound-state strong-field QED

    Science.gov (United States)

    Schmidt, S.; Billowes, J.; Bissell, M. L.; Blaum, K.; Garcia Ruiz, R. F.; Heylen, H.; Malbrunot-Ettenauer, S.; Neyens, G.; Nörtershäuser, W.; Plunien, G.; Sailer, S.; Shabaev, V. M.; Skripnikov, L. V.; Tupitsyn, I. I.; Volotka, A. V.; Yang, X. F.

    2018-04-01

    The hyperfine structure splitting in the 6p3 3/2 4S → 6p2 7 s 1/2 4P transition at 307 nm in atomic 208Bi was measured with collinear laser spectroscopy at ISOLDE, CERN. The hyperfine A and B factors of both states were determined with an order of magnitude improved accuracy. Based on these measurements, theoretical input for the hyperfine structure anomaly, and results from hyperfine measurements on hydrogen-like and lithium-like 209Bi80+,82+, the nuclear magnetic moment of 208Bi has been determined to μ (208Bi) = + 4.570 (10)μN. Using this value, the transition energy of the ground-state hyperfine splitting in hydrogen-like and lithium-like 208Bi80+,82+ and their specific difference of -67.491(5)(148) meV are predicted. This provides a means for an experimental confirmation of the cancellation of nuclear structure effects in the specific difference in order to exclude such contributions as the cause of the hyperfine puzzle, the recently reported 7-σ discrepancy between experiment and bound-state strong-field QED calculations of the specific difference in the hyperfine structure splitting of 209Bi80+,82+.

  10. Biologically relevant conformational features of linear and cyclic proteolipid protein (PLP) peptide analogues obtained by high-resolution nuclear magnetic resonance and molecular dynamics

    Science.gov (United States)

    Kordopati, Golfo G.; Tzoupis, Haralambos; Troganis, Anastassios N.; Tsivgoulis, Gerasimos M.; Golic Grdadolnik, Simona; Simal, Carmen; Tselios, Theodore V.

    2017-09-01

    Proteolipid protein (PLP) is one of the main proteins of myelin sheath that are destroyed during the progress of multiple sclerosis (MS). The immunodominant PLP139-151 epitope is known to induce experimental autoimmune encephalomyelitis (EAE, animal model of MS), wherein residues 144 and 147 are recognized by T cell receptor (TCR) during the formation of trimolecular complex with peptide-antigen and major histocompability complex. The conformational behavior of linear and cyclic peptide analogues of PLP, namely PLP139-151 and cyclic (139-151) (L144, R147) PLP139-151, have been studied in solution by means of nuclear magnetic resonance (NMR) methods in combination with unrestrained molecular dynamics simulations. The results indicate that the side chains of mutated amino acids in the cyclic analogue have different spatial orientation compared with the corresponding side chains of the linear analogue, which can lead to reduced affinity to TCR. NMR experiments combined with theoretical calculations pave the way for the design and synthesis of potent restricted peptides of immunodominant PLP139-151 epitope as well as non peptide mimetics that rises as an ultimate goal.

  11. Defining and modeling the soil geochemical background of heavy metals from the Hengshi River watershed (southern China): Integrating EDA, stochastic simulation and magnetic parameters

    International Nuclear Information System (INIS)

    Zhou Xu; Xia Beicheng

    2010-01-01

    It is crucial to separate the soil geochemical background concentrations from anthropogenic anomalies and to provide a realistic environmental geochemical map honoring the fluctuations in original data. This study was carried out in the Hengshi River watershed, north of Guangdong, China and the method proposed combined exploratory data analysis (EDA), sequential indicator co-simulation (SIcS) and the ratio of isothermal remnant magnetization (S 100 = -IRM -100mT /SIRM). The results showed that this is robust procedure for defining and mapping soil geochemical background concentrations in mineralized regions. The rock magnetic parameter helps to improve the mapping process by distinguishing anthropogenic influences. In this study, the geochemical backgrounds for four potentially toxic heavy metals (copper 200 mg/kg; zinc 230 mg/kg; lead 190 mg/kg and cadmium 1.85 mg/kg) Cu, Zn and Cd exceeded the soil Grade II limits (for pH < 6.5) from the Chinese Environmental Quality Standard for Soils (GB 15618-1995) (EQSS) which are 100, 200, 250 and 0.3 mg/kg for Cu, Zn, Pb and Cd, respectively. In particular, the geochemical background level for Cd exceeds standard six times. Results suggest that local public health is at high-risk along the riparian region of the Hengshi River, although the watershed ecosystem has not been severely disturbed.

  12. Modifications in Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters After α-Particle-Emitting {sup 227}Th-trastuzumab Therapy of HER2-Expressing Ovarian Cancer Xenografts

    Energy Technology Data Exchange (ETDEWEB)

    Heyerdahl, Helen, E-mail: Helen.Heyerdahl@rr-research.no [Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital - The Norwegian Radium Hospital, Oslo (Norway); Røe, Kathrine [Department of Oncology, Division of Medicine, Akershus University Hospital, Lørenskog (Norway); Brevik, Ellen Mengshoel [Department of Research and Development, Algeta ASA, Oslo (Norway); Dahle, Jostein [Nordic Nanovector AS, Oslo (Norway)

    2013-09-01

    Purpose: The purpose of this study was to investigate the effect of α-particle-emitting {sup 227}Th-trastuzumab radioimmunotherapy on tumor vasculature to increase the knowledge about the mechanisms of action of {sup 227}Th-trastuzumab. Methods and Materials: Human HER2-expressing SKOV-3 ovarian cancer xenografts were grown bilaterally in athymic nude mice. Mice with tumor volumes 253 ± 36 mm{sup 3} (mean ± SEM) were treated with a single injection of either {sup 227}Th-trastuzumab at a dose of 1000 kBq/kg body weight (treated group, n=14 tumors) or 0.9% NaCl (control group, n=10 tumors). Dynamic T1-weighted contrast-enhanced magnetic resonance imaging (DCEMRI) was used to study the effect of {sup 227}Th-trastuzumab on tumor vasculature. DCEMRI was performed before treatment and 1, 2, and 3 weeks after therapy. Tumor contrast-enhancement curves were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared with the corresponding parameters of control tumors. Results: Significant increases of k{sub ep}, the rate constant of diffusion from the extravascular extracellular space to the plasma (P<.05), and k{sub el,} the rate of clearance of contrast agent from the plasma (P<.01), were seen in the radioimmunotherapy group 2 and 3 weeks after injection, compared with the control group. The product of k{sub ep} and the amplitude parameter A, associated with increased vessel permeability and perfusion, was also significantly increased in the radioimmunotherapy group 2 and 3 weeks after injection (P<.01). Conclusions: Pharmacokinetic modeling of MRI contrast-enhancement curves evidenced significant alterations in parameters associated with increased tumor vessel permeability and tumor perfusion after {sup 227}Th-trastuzumab treatment of HER2-expressing ovarian cancer xenografts.

  13. Relationship between myocardial T2* values and cardiac volumetric and functional parameters in β-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels

    Energy Technology Data Exchange (ETDEWEB)

    Liguori, Carlo, E-mail: c.liguori@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Pitocco, Francesca, E-mail: f.pitocco@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Di Giampietro, Ilenia, E-mail: i.digiampietro@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Vivo, Aldo Eros de, E-mail: devivoeros@gmail.com [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Unit of Measurements and Biomedical Instrumentation, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Cianciulli, Paolo, E-mail: CIANCIULLI.PAOLO@aslrmc.it [Thalassemia Unit, Ospedale Sant Eugenio, Piazzale dell’Umanesimo 10, 00143 Rome (Italy); Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy)

    2013-09-15

    Purpose: Myocardial T2* cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2* value in myocardium and left–right ventricular volumetric and functional parameters and to evaluate the existing associations between left–right ventricles volumetric and functional parameter, myocardial T2* values and blood ferritin levels. Materials and methods: A retrospective analysis of 208 patients with β-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2* measurements, and volumetric functions were analyzed using the steady state free precession sequence. Results: A significant correlation was observed between EFLV and T2* (p = 0.0001), EFRV and T2* (p = 0.0279). An inverse correlation was present between DVLV and T2* (p = 0.0468), SVLV and T2* (p = 0.0003), SVRV and T2* (p = 0.0001). There was no significant correlation between cardiac T2* and LV–RV mass indices. A significant correlation was observed between T2* and serum ferritin levels (p < 0.001) and between EFLV and serum ferritin (p < 0.05). Conclusion: Myocardial iron load assessed by T2* cardiac magnetic resonance is associated with deterioration in left–right ventricular function; this is more evident when T2* values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients.

  14. Relationship between myocardial T2* values and cardiac volumetric and functional parameters in β-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels

    International Nuclear Information System (INIS)

    Liguori, Carlo; Pitocco, Francesca; Di Giampietro, Ilenia; Vivo, Aldo Eros de; Schena, Emiliano; Cianciulli, Paolo; Zobel, Bruno Beomonte

    2013-01-01

    Purpose: Myocardial T2* cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2* value in myocardium and left–right ventricular volumetric and functional parameters and to evaluate the existing associations between left–right ventricles volumetric and functional parameter, myocardial T2* values and blood ferritin levels. Materials and methods: A retrospective analysis of 208 patients with β-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2* measurements, and volumetric functions were analyzed using the steady state free precession sequence. Results: A significant correlation was observed between EFLV and T2* (p = 0.0001), EFRV and T2* (p = 0.0279). An inverse correlation was present between DVLV and T2* (p = 0.0468), SVLV and T2* (p = 0.0003), SVRV and T2* (p = 0.0001). There was no significant correlation between cardiac T2* and LV–RV mass indices. A significant correlation was observed between T2* and serum ferritin levels (p < 0.001) and between EFLV and serum ferritin (p < 0.05). Conclusion: Myocardial iron load assessed by T2* cardiac magnetic resonance is associated with deterioration in left–right ventricular function; this is more evident when T2* values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients

  15. Charged particle confinement in magnetic mirror

    International Nuclear Information System (INIS)

    Bora, D.; John, P.I.; Saxena, Y.C.; Varma, R.K.

    1982-01-01

    The behaviour of single charged particle trapped in a magnetic mirror has been investigated experimentally. The particle injected off axis and trapped in a magnetic mirror, leak out of the mirror with the leakage characterized by multiple decay times. The observed decay times are in good agreement with predictions of a ''wave mechanical like'' model by Varma, over a large range of relevant parameters. (author)

  16. Magnetization fluctuation analysis and superconducting parameters of La0.5RE0.5BaCaCu3O7-δ(RE=Y, Sm, Gd, Dy, Ho, Yb) superconductor

    International Nuclear Information System (INIS)

    Parra Vargas, C.A.; Pimentel, J.L.; Pureur, P.; Landinez Tellez, D.A.; Roa-Rojas, J.

    2009-01-01

    In this work we report the analysis of magnetization experimental data of the La 0.5 RE 0.5 BaCaCu 3 O 7-δ (RE=Y, Sm, Gd, Dy, Ho, Yb) superconducting system. The data are analyzed in terms of thermal fluctuations on the magnetization excess ΔM(T) for different values of temperature in each one of the samples. We describe a procedure for extracting the penetration depth λ ab (∼1571A) and the coherence length ξ ab (∼1.52A) parameters from the magnetization, as a function of the applied magnetic field. This procedure was performed for polycrystalline samples of La 0.5 RE 0.5 BaCaCu 3 O 7-δ by using the theory of Bulaevskii, Ledvij and Kogan, which analyzes the vortex fluctuation in superconducting materials within the Lawrence-Doniach framework. These data allowed to determine the characteristic temperature value T * (73, 58, 48, 57, 56, 71 K, for RE=Y, Sm, Gd, Dy, Ho, Yb, respectively) in the magnetization curves for several magnetic fields. We calculated the data of magnetization excess from the curves of magnetization as a function of logarithm of applied field. We notice that the values for these superconducting parameters are in agreement with the reports for high temperature superconductors. The obtained value of superconducting volumetric fraction is compared with that obtained through the measure of the Meissner effect.

  17. Influence of amplitude-related perfusion parameters in the parotid glands by non-fat-saturated dynamic contrast-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Chiu, Su-Chin; Cheng, Cheng-Chieh; Chang, Hing-Chiu; Chung, Hsiao-Wen; Chiu, Hui-Chu; Liu, Yi-Jui; Hsu, Hsian-He; Juan, Chun-Jung

    2016-01-01

    Purpose: To verify whether quantification of parotid perfusion is affected by fat signals on non-fat-saturated (NFS) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and whether the influence of fat is reduced with fat saturation (FS). Methods: This study consisted of three parts. First, a retrospective study analyzed DCE-MRI data previously acquired on different patients using NFS (n = 18) or FS (n = 18) scans. Second, a phantom study simulated the signal enhancements in the presence of gadolinium contrast agent at six concentrations and three fat contents. Finally, a prospective study recruited nine healthy volunteers to investigate the influence of fat suppression on perfusion quantification on the same subjects. Parotid perfusion parameters were derived from NFS and FS DCE-MRI data using both pharmacokinetic model analysis and semiquantitative parametric analysis. T tests and linear regression analysis were used for statistical analysis with correction for multiple comparisons. Results: NFS scans showed lower amplitude-related parameters, including parameter A, peak enhancement (PE), and slope than FS scans in the patients (all with P < 0.0167). The relative signal enhancement in the phantoms was proportional to the dose of contrast agent and was lower in NFS scans than in FS scans. The volunteer study showed lower parameter A (6.75 ± 2.38 a.u.), PE (42.12% ± 14.87%), and slope (1.43% ± 0.54% s"−"1) in NFS scans as compared to 17.63 ± 8.56 a.u., 104.22% ± 25.15%, and 9.68% ± 1.67% s"−"1, respectively, in FS scans (all with P < 0.005). These amplitude-related parameters were negatively associated with the fat content in NFS scans only (all with P < 0.05). Conclusions: On NFS DCE-MRI, quantification of parotid perfusion is adversely affected by the presence of fat signals for all amplitude-related parameters. The influence could be reduced on FS scans.

  18. Influence of amplitude-related perfusion parameters in the parotid glands by non-fat-saturated dynamic contrast-enhanced magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Su-Chin [Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan, Republic of China and Department of Radiology, Tri-Service General Hospital, Taipei 114, Taiwan (China); Cheng, Cheng-Chieh [Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115 (United States); Chang, Hing-Chiu [Department of Diagnostic Radiology, The University of Hong Kong (Hong Kong); Chung, Hsiao-Wen [Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei 106, Taiwan (China); Department of Radiology, Tri-Service General Hospital, Taipei 114, Taiwan (China); Department of Radiology, National Defense Medical Center, Taipei 114, Taiwan (China); Chiu, Hui-Chu [Ph.D. Program of Technology Management, Chung Hua University, Hsinchu 300, Taiwan (China); Liu, Yi-Jui [Department of Automatic Control Engineering, Feng-Chia University, Taichung 407, Taiwan (China); Hsu, Hsian-He; Juan, Chun-Jung, E-mail: peterjuancj@yahoo.com.tw [Department of Radiology, Tri-Service General Hospital, Taipei 114, Taiwan and Department of Radiology, National Defense Medical Center, Taipei 114, Taiwan (China)

    2016-04-15

    Purpose: To verify whether quantification of parotid perfusion is affected by fat signals on non-fat-saturated (NFS) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and whether the influence of fat is reduced with fat saturation (FS). Methods: This study consisted of three parts. First, a retrospective study analyzed DCE-MRI data previously acquired on different patients using NFS (n = 18) or FS (n = 18) scans. Second, a phantom study simulated the signal enhancements in the presence of gadolinium contrast agent at six concentrations and three fat contents. Finally, a prospective study recruited nine healthy volunteers to investigate the influence of fat suppression on perfusion quantification on the same subjects. Parotid perfusion parameters were derived from NFS and FS DCE-MRI data using both pharmacokinetic model analysis and semiquantitative parametric analysis. T tests and linear regression analysis were used for statistical analysis with correction for multiple comparisons. Results: NFS scans showed lower amplitude-related parameters, including parameter A, peak enhancement (PE), and slope than FS scans in the patients (all with P < 0.0167). The relative signal enhancement in the phantoms was proportional to the dose of contrast agent and was lower in NFS scans than in FS scans. The volunteer study showed lower parameter A (6.75 ± 2.38 a.u.), PE (42.12% ± 14.87%), and slope (1.43% ± 0.54% s{sup −1}) in NFS scans as compared to 17.63 ± 8.56 a.u., 104.22% ± 25.15%, and 9.68% ± 1.67% s{sup −1}, respectively, in FS scans (all with P < 0.005). These amplitude-related parameters were negatively associated with the fat content in NFS scans only (all with P < 0.05). Conclusions: On NFS DCE-MRI, quantification of parotid perfusion is adversely affected by the presence of fat signals for all amplitude-related parameters. The influence could be reduced on FS scans.

  19. The growth temperature and measurement temperature dependences of soft magnetic properties and effective damping parameter of (FeCo-Al alloy thin films

    Directory of Open Access Journals (Sweden)

    Yusuke Ariake

    2018-05-01

    Full Text Available The soft magnetic properties and effective damping parameters of Fe73Co25Al2 alloy thin films are discussed. The effective damping parameter αeff measured by ferromagnetic resonance for the 10 nm-thick sample is nearly constant (≈0.004 ± 0.0008 for a growth temperature Ts from ambient to 200 °C, and then tends to decrease for higher temperatures and αeff is 0.002 ± 0.0004 at Ts = 300 °C. For the 80 nm-thick sample, the αeff seems to increase with Ts from αeff = 0.001 ± 0.0002 at Ts = ambient to αeff = 0.002 ± 0.0004. The αeff is found nearly constant (αeff = 0.004 ± 0.0008 over a temperature range from 10 to 300 K for the 10 nm films with the different Ts (ambient, 100 and 200 °C. Together with an increasing non-linearity of the frequency dependence of the linewidth at low Ts, extrinsic contributions such as two-magnon scattering dominate the observed temperature dependence of effective damping and linewidth.

  20. Contrast-enhanced magnetic resonance imaging of the breast: the value of pharmacokinetic parameters derived from fast dynamic imaging during initial enhancement in classifying lesions

    International Nuclear Information System (INIS)

    Veltman, J.; Stoutjesdijk, M.; Mann, R.; Huisman, H.J.; Barentsz, J.O.; Blickman, J.G.; Boetes, C.

    2008-01-01

    The value of pharmacokinetic parameters derived from fast dynamic imaging during initial enhancement in characterizing breast lesions on magnetic resonance imaging (MRI) was evaluated. Sixty-eight malignant and 34 benign lesions were included. In the scanning protocol, high temporal resolution imaging was combined with high spatial resolution imaging. The high temporal resolution images were recorded every 4.1 s during initial enhancement (fast dynamic analysis). The high spatial resolution images were recorded at a temporal resolution of 86 s (slow dynamic analysis). In the fast dynamic evaluation pharmacokinetic parameters (K trans , V e and k ep ) were evaluated. In the slow dynamic analysis, each lesion was scored according to the BI-RADS classification. Two readers evaluated all data prospectively. ROC and multivariate analysis were performed. The slow dynamic analysis resulted in an AUC of 0.85 and 0.83, respectively. The fast dynamic analysis resulted in an AUC of 0.83 in both readers. The combination of both the slow and fast dynamic analyses resulted in a significant improvement of diagnostic performance with an AUC of 0.93 and 0.90 (P = 0.02). The increased diagnostic performance found when combining both methods demonstrates the additional value of our method in further improving the diagnostic performance of breast MRI. (orig.)

  1. Detailed crystallization study of co-precipitated Y1.47 Gd1.53 Fe5 O12 and relevant magnetic properties

    International Nuclear Information System (INIS)

    Serra, Rogerio Arving; Ogasawara, Tsuneharu; Ogasawara, Angelica Soares

    2007-01-01

    The crystallization process of co-precipitated Y 1.5 Gd 1.5 Fe 5 O 12 powder heated up to 1000 deg C at rate of 5 deg C min -1 was investigated. Above 810 deg C crystalline Y 1.47 Gd 1.53 Fe 5 O 12 was obtained with a lattice parameter of 12.41 A and a theoretical density of 5.84 g cm -3 . Dry pressed rings were sintered at 1270 and 1320 deg C, increasing the grain-size from 3.1 to 6.5 μm, the theoretical density by 87.6 to 95.3% and decreasing H c from 2.9725 to 1.4005 Oe. Additionally, Hc increased when the frequency of the hysteresis graph varied from 60 Hz to 10 kHz, the curie temperature was 282.4 deg C and Ms equalled 9.25 emu g -1 (0.17 kG) agreeing well with the B s -value of the hysteresis graph and literature values. (author)

  2. Forensic age estimation by magnetic resonance imaging of the knee: the definite relevance in bony fusion of the distal femoral- and the proximal tibial epiphyses using closest-to-bone T1 TSE sequence

    Energy Technology Data Exchange (ETDEWEB)

    Ottow, Christian; Heindel, Walter [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Schulz, Ronald; Pfeiffer, Heidi; Schmeling, Andreas [University Hospital Muenster, Institute of Legal Medicine, Muenster (Germany); Vieth, Volker [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Klinikum Ibbenbueren, Clinic for Radiology, Ibbenbueren (Germany)

    2017-12-15

    To clarify the relevance of the bony fusion of the distal femoral and the proximal tibial epiphyses by means of magnetic resonance imaging (MRI), a prospective cross-sectional cohort study was performed with a special focus on a reliable determination of the 14th, 16th and 18th years of life. We scanned 658 German volunteers in the age bracket 12-24 years using a 3.0 T MR-scanner and utilising a T1 turbo spin-echo sequence representing true bone anatomy. Minimum, maximum, mean ± standard deviation and median with lower and upper quartiles were defined. Intra- and interobserver agreements were determined (Cohen's kappa). The statistical relevance of sex-related differences was analysed (Mann-Whitney U test, p < 0.05, exact, two-sided). The bony fusion took place before the 18th year of life in both epiphyses. The Mann-Whitney U test results imply significant sex-related differences for most stages. For both epiphyses, the intra observer (κ femur 0.961; tibia 0.971) and interobserver (κ femur 0.941; tibia 0.951) agreement levels were very good. The 14th and the 16th years of life can be determined in both sexes, but the completion of the 18th year of life cannot solely be determined by the bony fusion, as depicted by closest-to-bone MRI. (orig.)

  3. Forensic age estimation by magnetic resonance imaging of the knee: the definite relevance in bony fusion of the distal femoral- and the proximal tibial epiphyses using closest-to-bone T1 TSE sequence

    International Nuclear Information System (INIS)

    Ottow, Christian; Heindel, Walter; Schulz, Ronald; Pfeiffer, Heidi; Schmeling, Andreas; Vieth, Volker

    2017-01-01

    To clarify the relevance of the bony fusion of the distal femoral and the proximal tibial epiphyses by means of magnetic resonance imaging (MRI), a prospective cross-sectional cohort study was performed with a special focus on a reliable determination of the 14th, 16th and 18th years of life. We scanned 658 German volunteers in the age bracket 12-24 years using a 3.0 T MR-scanner and utilising a T1 turbo spin-echo sequence representing true bone anatomy. Minimum, maximum, mean ± standard deviation and median with lower and upper quartiles were defined. Intra- and interobserver agreements were determined (Cohen's kappa). The statistical relevance of sex-related differences was analysed (Mann-Whitney U test, p < 0.05, exact, two-sided). The bony fusion took place before the 18th year of life in both epiphyses. The Mann-Whitney U test results imply significant sex-related differences for most stages. For both epiphyses, the intra observer (κ femur 0.961; tibia 0.971) and interobserver (κ femur 0.941; tibia 0.951) agreement levels were very good. The 14th and the 16th years of life can be determined in both sexes, but the completion of the 18th year of life cannot solely be determined by the bony fusion, as depicted by closest-to-bone MRI. (orig.)

  4. Crystallographic parameters of magnetic Pr{sub 2}Fe{sub 14−x}Co{sub x}B-type alloys determined using anomalous x-ray diffraction with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Galego, E., E-mail: egalego@ipen.br; Serna, M.M.; Ramanathan, L.V.; Faria, R.N.

    2017-02-15

    Anomalous x-ray synchrotron diffraction was used to determine the crystallographic parameters of PrFeCoB-based magnetic alloys. The effect of cobalt concentration on the crystallographic parameters of the magnetically hard Pr{sub 2}Fe{sub 14−x}Co{sub x}B phase was studied. The results indicate that addition of cobalt has a marked effect on crystal structure. Variation of the c parameter decreased twice as much as the a parameter with increase in Co content. The positions of inequivalent atoms of the magnetically hard matrix phase ϕ in the Pr-based alloys were determined using Rietveld refinement. This permitted determination of the relative distance of each inequivalent atom from its nearest neighbors. Cobalt occupied the 16k{sub 2} site and Fe had a tendency to occupy the 8j{sub 2} sites located between the Kagomé layers. - Highlights: • Good magnetics properties can be achieved with addition of 4% and 8% Co. • Rietveld refinement is proposed for crystallographic parameters studies. • Co has preference to substitute Fe in 16k{sub 2} site and avoid the 8j{sub 2} site.

  5. A novel diagnostic parameter, foraminal stenotic ratio using three-dimensional magnetic resonance imaging, as a discriminator for surgery in symptomatic lumbar foraminal stenosis.

    Science.gov (United States)

    Yamada, Kentaro; Abe, Yuichiro; Satoh, Shigenobu; Yanagibashi, Yasushi; Hyakumachi, Takahiko; Masuda, Takeshi

    2017-08-01

    No previous studies have reported the radiological features of patients requiring surgery in symptomatic lumbar foraminal stenosis (LFS). This study aims to investigate the diagnostic accuracy of a novel technique, foraminal stenotic ratio (FSR), using three-dimensional magnetic resonance imaging for LFS at L5-S by comparing patients requiring surgery, patients with successful conservative treatment, and asymptomatic patients. This is a retrospective radiological comparative study. We assessed the magnetic resonance imaging (MRI) results of 84 patients (168 L5-S foramina) aged ≥40 years without L4-L5 lumbar spinal stenosis. The foramina were divided into three groups following standardized treatment: stenosis requiring surgery (20 foramina), stenosis with successful conservative treatment (26 foramina), and asymptomatic stenotic foramen (122 foramina). Foraminal stenotic ratio was defined as the ratio of the length of the stenosis to the length of the foramen on the reconstructed oblique coronal image, referring to perineural fat obliterations in whole oblique sagittal images. We also evaluated the foraminal nerve angle and the minimum nerve diameter on reconstructed images, and the Lee classification on conventional T1 images. The differences in each MRI parameter between the groups were investigated. To predict which patients require surgery, receiver operating characteristic (ROC) curves were plotted after calculating the area under the ROC curve. The FSR showed a stepwise increase when comparing asymptomatic, conservative, and surgical groups (mean, 8.6%, 38.5%, 54.9%, respectively). Only FSR was significantly different between the surgical and conservative groups (p=.002), whereas all parameters were significantly different comparing the symptomatic and asymptomatic groups. The ROC curve showed that the area under the curve for FSR was 0.742, and the optimal cutoff value for FSR for predicting a surgical requirement in symptomatic patients was 50

  6. Comparison of morphological and kinetic parameters in distinction of benign and malignant breast lesions in dynamic contrast enhanced magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Direnç Özlem Aksoy

    2013-12-01

    Full Text Available Objective: To evaluate the value of qualitative morphologicaland kinetic data and quantitative kinetic data indistinction of malignancy in dynamic contrast enhancedmagnetic resonance imaging (DCE-MRI of the breast.Methods: DCE-MRIs of 49 subjects were evaluated.Morphological and contrast enhancement parameters of95 lesions were recorded in these subjects. Post-contrastkinetic behavior of these lesions were also investigated.Among the quantitative parameters, relative enhancements(E1, E2, Epeak, time-to-peak (Tpeak, slope ofcurve (Slope, signal enhancement ratio (SER, and maximumintensity time ratio (MITR were calculated. Theseresults were compared with the pathological diagnosis.Results: Spiculated contour (100%, rim enhancement(97.87%, irregular shape (95.74%, and irregular margin(91.49% were the most specific morphological featuresof malignancy in mass lesions. In non-mass lesions, focalzone (91.49% was the most specific feature of malignancy.74.5% of the benign lesions showed type 1, 77.1%of the malignant lesions showed type 2 and 3 curves accordingto the kinetic curve evaluation. All quantitativeparameters except Epeak were found to be statisticallysignificant in distinction of malignancy.Conclusion: None of the morphological features of thebenign lesions were found to be significantly specific.More specific features can be described for malignantlesions. Early behavior of the kinetic curve is not usefulfor diagnosis of malignancy but the intermediate and latebehavior gives useful information. Quantitative data involvedin this study might be promising.Key words: Morphological, kinetic, breast lesions, magnetic resonance imaging, dynamic

  7. Quantitative cardiovascular magnetic resonance in pregnant women: cross-sectional analysis of physiological parameters throughout pregnancy and the impact of the supine position.

    Science.gov (United States)

    Rossi, Alexia; Cornette, Jerome; Johnson, Mark R; Karamermer, Yusuf; Springeling, Tirza; Opic, Petra; Moelker, Adriaan; Krestin, Gabriel P; Steegers, Eric; Roos-Hesselink, Jolien; van Geuns, Robert-Jan M

    2011-06-27

    There are physiological reasons for the effects of positioning on hemodynamic variables and cardiac dimensions related to altered intra-abdominal and intra-thoracic pressures. This problem is especially evident in pregnant women due to the additional aorto-caval compression by the enlarged uterus. The purpose of this study was to investigate the effect of postural changes on cardiac dimensions and function during mid and late pregnancy using cardiovascular magnetic resonance (CMR). Healthy non-pregnant women, pregnant women at 20th week of gestation and at 32nd week of gestation without history of cardiac disease were recruited to the study and underwent CMR in supine and left lateral positions. Cardiac hemodynamic parameters and dimensions were measured and compared between both positions. Five non-pregnant women, 6 healthy pregnant women at mid pregnancy and 8 healthy pregnant women at late pregnancy were enrolled in the study. In the group of non-pregnant women left ventricular (LV) cardiac output (CO) significantly decreased by 9% (p=0.043) and right ventricular (RV) end-diastolic volume (EDV) significantly increased by 5% (p=0.043) from the supine to the left lateral position. During mid pregnancy LV ejection fraction (EF), stroke volume (SV), left atrium lateral diameter and left atrial supero-inferior diameter increased significantly from the supine position to the left lateral position: 8%, 27%, 5% and 11%, respectively (ppregnancy a significant increment of LV EF, EDV, SV and CO was observed in the left lateral position: 11%, 21%, 35% and 24% (ppregnancy positional changes affect significantly cardiac hemodynamic parameters and dimensions. Pregnant women who need serial studies by CMR should be imaged in a consistent position. From as early as 20 weeks the left lateral position should be preferred on the supine position because it positively affects venous return, SV and CO.

  8. Quantitative cardiovascular magnetic resonance in pregnant women: cross-sectional analysis of physiological parameters throughout pregnancy and the impact of the supine position

    Directory of Open Access Journals (Sweden)

    Moelker Adriaan

    2011-06-01

    Full Text Available Abstract Background There are physiological reasons for the effects of positioning on hemodynamic variables and cardiac dimensions related to altered intra-abdominal and intra-thoracic pressures. This problem is especially evident in pregnant women due to the additional aorto-caval compression by the enlarged uterus. The purpose of this study was to investigate the effect of postural changes on cardiac dimensions and function during mid and late pregnancy using cardiovascular magnetic resonance (CMR. Methods Healthy non-pregnant women, pregnant women at 20th week of gestation and at 32nd week of gestation without history of cardiac disease were recruited to the study and underwent CMR in supine and left lateral positions. Cardiac hemodynamic parameters and dimensions were measured and compared between both positions. Results Five non-pregnant women, 6 healthy pregnant women at mid pregnancy and 8 healthy pregnant women at late pregnancy were enrolled in the study. In the group of non-pregnant women left ventricular (LV cardiac output (CO significantly decreased by 9% (p = 0.043 and right ventricular (RV end-diastolic volume (EDV significantly increased by 5% (p = 0.043 from the supine to the left lateral position. During mid pregnancy LV ejection fraction (EF, stroke volume (SV, left atrium lateral diameter and left atrial supero-inferior diameter increased significantly from the supine position to the left lateral position: 8%, 27%, 5% and 11%, respectively (p Conclusions During pregnancy positional changes affect significantly cardiac hemodynamic parameters and dimensions. Pregnant women who need serial studies by CMR should be imaged in a consistent position. From as early as 20 weeks the left lateral position should be preferred on the supine position because it positively affects venous return, SV and CO.

  9. Evaluation of Tumor Angiogenesis Using Dynamic Enhanced Magnetic Resonance Imaging: Comparison of Plasma Vascular Endothelial Growth Factor, Hemodynamic, and Pharmacokinetic Parameters

    International Nuclear Information System (INIS)

    Ikeda, O.; Nishimura, R.; Miyayama, H.; Yasunaga, T.; Ozaki, Y.; Tuji, A.; Yamashita, Y.

    2004-01-01

    Purpose: To assess whether tumor angiogenesis of breast cancers can be predicted on the basis of dynamic magnetic resonance imaging (MRI). Material and Methods: Seventy-one patients with 71 breast cancers underwent Gd-DTPA enhanced dynamic MRI. Two regions of interest measurements were obtained in the periphery and in the center of the breast cancers. Hemodynamic parameters obtained by dynamic MRI included peak time, contrast enhancement ratio (CE ratio), and washout ratio. The triexponential concentration curve of Gd-DTPA was fitted to a theoretical model based on compartmental analysis. The transfer constant (or permeability surface product per unit volume of compartment 'k') was obtained using this method. Tumor angiogenesis was assessed by plasma vascular endothelial growth factor (P-VEGF). Results: The P-VEGF was positive in 28 of 71 tumors (39%). The CE ratio, washout ratio, and k in the periphery in P-VEGF positive breast cancers (mean 178%, 18%, and 1.5x10 -2 (s-1)) were significantly greater (P -2 (s-1)). The peak time in the periphery in P-VEGF positive breast cancers was more marked than for P-VEGF negative breast cancers, but this difference was not significant. Conclusion: The hemodynamic and pharmacokinetic analysis of MRI provides valuable information about angiogenesis of breast cancers

  10. Experimental determination of some equilibrium parameter of Damavand tokamak by magnetic probe measurements for representing a physical model for plasma vertical movement.

    Science.gov (United States)

    Farahani, N Darestani; Davani, F Abbasi

    2015-10-01

    This investigation is about plasma modeling for the control of vertical instabilities in Damavand tokamak. This model is based on online magnetic measurement. The algebraic equation defining the vertical position in this model is based on instantaneous force-balance. Two parameters in this equation, including decay index, n, and lambda, Λ, have been considered as functions of time-varying poloidal field coil currents and plasma current. Then these functions have been used in a code generated for modeling the open loop response of plasma. The main restriction of the suitability analysis of the model is that the experiments always have to be performed in the presence of a control loop for stabilizing vertical position. As a result, open loop response of the system has been identified from closed loop experimental data by nonlinear neural network identification method. The results of comparison of physical model with identified open loop response from closed loop experiments show root mean square error percentage less than 10%. The results are satisfying that the physical model is useful as a Damavand tokamak vertical movement simulator.

  11. Rock magnetic parameters and Sr-Nd isotopes as tracers of continental erosion in Red Sea and in Gulf of Aden during the last 20,000 years

    Science.gov (United States)

    Rojas, V.; Bouilloux, A.; Meynadier, L.; Valet, J.-P.; Joron, J.-L.

    2012-04-01

    in ɛNd values (0.5 ɛNd units for the detrital fraction), reflecting the greater communication of the Gulf of Aden basin with the open ocean. Variations in the detrital ɛNd values suggest a change of the eolian particles source from the Sahara region during glacial periods, to the Arabian-Nubian shield during interglacial periods. An increase of the dissolved ɛNd values in both basins between 15 and 10 kyr indicates an intensification of precipitation in this region and, as a consequence, a preferential alteration of the basaltic terrain. The ɛNd data are compared with magnetic susceptibility and magnetic mineralogy data in order to discriminate between influences of continental erosion and weathering, and redox conditions in the basins during the considered period of time. We found an overall covariation of magnetic parameters with the detrital ɛNd and sea water ɛNd of both cores except for the H1 event in the Gulf of Aden. Strontium isotope measurements of the detrital fractions are in progress to constrain the origin of the sources.

  12. Functional and morphological parameters with tissue characterization of cardiovascular magnetic imaging in clinically verified ''infarct-like myocarditis''

    Energy Technology Data Exchange (ETDEWEB)

    Schwab, Johannes [Paracelsus Medical Univ., General Hospital Nuremberg (Germany). Dept. of Cardiology and Radiology; Rogg, H.J.; Pauschinger, M.; Fessele, K. [Paracelsus Medical Univ., General Hospital Nuremberg (Germany). Dept. of Cardiology; Bareiter, T.; Baer, I. [Paracelsus Medical Univ., General Hospital Nuremberg (Germany). Dept. of Cardiology and Neuroradiology; Loose, R. [Paracelsus Medical Univ., General Hospital Nuremberg (Germany). Dept. of Radiology

    2016-04-15

    Cardiac magnetic resonance (CMR) has increasingly proved to be a valuable diagnostic tool for evaluating patients with suspected myocarditis. The objective of this study was to evaluate the diagnostic value of functional and morphological parameters including tissue characterization in patients with ''infarct-like myocarditis''. 43 patients with clinically verified cases of ''infarct-like myocarditis'' (median time to MRI scanning after admission for acute symptoms 3 days) and 35 control patients matched by age and sex were included in this retrospective case control study. In this study we used a 1.5 T MRI scanner conducting steady-state-free-precession sequences, T2-weighted imaging, T1-weighted imaging before and after contrast administration and late gadolinium enhancement sequences. According to the recommendations for CMR diagnosis of myocarditis (Lake Louise consensus criteria), a scan was positive for acute myocarditis if 2 of 3 CMR criteria were present. 30 % of the patients with ''infarct-like myocarditis'' had a reduced left ventricular ejection fraction, 11 % had an increased LV end-diastolic volume index and 35 % had an increased LV mass index. The sensitivity of wall motion abnormalities was 63 % with a regional distribution in 49 %. In 47 % of cases regional wall motion abnormalities were present in the lateral left ventricular segments. Pericardial effusions were discovered in 65 % of cases with a circular appearance in 21 % and focal manifestation in 44 %. The diagnostic sensitivity, specificity, and accuracy of CMR in patients with ''infarct-like myocarditis'' were 67 %, 100 % and 82 %, respectively. The LGE alone was the most sensitive test parameter with 86 %, providing a specificity of 100 % and accuracy of 92 %. Our study results can be applied to the subgroup of patients with ''infarct-like myocarditis'', where we found that LGE alone was the

  13. Relation between pO2, 31P magnetic resonance spectroscopy parameters and treatment outcome in patients with high-grade soft tissue sarcomas treated with thermoradiotherapy

    International Nuclear Information System (INIS)

    Dewhirst, Mark W.; Poulson, Jean M.; Yu Daohai; Sanders, Linda; Lora-Michiels, Michael; Vujaskovic, Zeljko; Jones, Ellen L.; Samulski, Thaddeus V.; Powers, Barbara E.; Brizel, David M.; Prosnitz, Leonard R.; Charles, H. Cecil

    2005-01-01

    Purpose: In a prior study, the combination of 31 P magnetic resonance spectroscopy (MRS)-based intracellular pH (pHi) and T2 relaxation time was highly predictive of the pathologic complete response (pCR) rate in a small series of patients with soft tissue sarcomas (STSs) treated with thermoradiotherapy. Changes in the magnetic resonance metabolite ratios and pO 2 were related to the pCR rate. Hypoxia also correlated with a greater likelihood for the development of metastases. Because of the limited number of patients in the prior series, we initiated this study to determine whether the prior observations were repeatable and whether 31 P MRS lipid-related resonances were related to a propensity for metastasis. Methods and materials: Patients with high-grade STSs were enrolled in an institutional review board-approved Phase II thermoradiotherapy trial. All tumors received daily external beam radiotherapy (1.8-2.0 Gy, five times weekly) to a total dose of 30-50 Gy. Hyperthermia followed radiotherapy by 31 P metabolite ratios, pHi, and T2 relaxation time. The median pO 2 and hypoxic fraction were determined using pO 2 histography. Comparisons between experimental endpoints and the pCR rate and metastasis-free and overall survival were made. Results: Of 35 patients, 21 and 28 had reportable pretreatment MRS/MRI and pO 2 data, respectively. The cutpoints for a previously tested receiver operating curve for a pCR were T2 = 100 and pHi = 7.3. In the current series, few tumors fell below the cutpoints so validation was not possible. The phosphodiester (PDE)/inorganic phosphate (Pi) ratio and hypoxic fraction correlated inversely with the pCR rate in the current series (Spearman correlation coefficient -0.51, p = 0.017; odds ratio of percentage of necrosis ≥95% = 0.01 for a 1% increase in the hypoxic fraction; Wald p = 0.036). The pretreatment phosphomonoester (PME)/Pi ratio also correlated inversely with the pCR rate (odds ratio of percentage of necrosis ≥95% = 0

  14. Why relevance theory is relevant for lexicography

    DEFF Research Database (Denmark)

    Bothma, Theo; Tarp, Sven

    2014-01-01

    This article starts by providing a brief summary of relevance theory in information science in relation to the function theory of lexicography, explaining the different types of relevance, viz. objective system relevance and the subjective types of relevance, i.e. topical, cognitive, situational...... that is very important for lexicography as well as for information science, viz. functional relevance. Since all lexicographic work is ultimately aimed at satisfying users’ information needs, the article then discusses why the lexicographer should take note of all these types of relevance when planning a new...... dictionary project, identifying new tasks and responsibilities of the modern lexicographer. The article furthermore discusses how relevance theory impacts on teaching dictionary culture and reference skills. By integrating insights from lexicography and information science, the article contributes to new...

  15. Combination of magnetic parameters and heavy metals to discriminate soil-contamination sources in Yinchuan--a typical oasis city of Northwestern China.

    Science.gov (United States)

    Xia, Dunsheng; Wang, Bo; Yu, Ye; Jia, Jia; Nie, Yan; Wang, Xin; Xu, Shujing

    2014-07-01

    Various industrial processes and vehicular traffic result in harmful emissions containing both magnetic minerals and heavy metals. In this study, we investigated the levels of magnetic and heavy metal contamination of topsoils from Yinchuan city in northwestern China. The results demonstrate that magnetic mineral assemblages in the topsoil are dominated by pseudo-single domain (PSD) and multi-domain (MD) magnetite. The concentrations of anthropogenic heavy metals (Cr, Cu, Pb and Zn) and the magnetic properties of χlf, SIRM, χARM, and 'SOFT' and 'HARD' remanence are significantly correlated, suggesting that the magnetic minerals and heavy metals have common sources. Combined use of principal components and fuzzy cluster analysis of the magnetic and chemical data set indicates that the magnetic and geochemical properties of the particulates emitted from different sources vary significantly. Samples from university campus and residential areas are mainly affected by crustal material, with low concentrations of magnetic minerals and heavy metals, while industrial pollution sources are characterized by high concentrations of coarse magnetite and Cr, Cu, Pb and Zn. Traffic pollution is characterized by Pb and Zn, and magnetite. Magnetic measurements of soils are capable of differentiating sources of magnetic minerals and heavy metals from industrial processes, vehicle fleets and soil parent material. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Mass-radius relation for magnetized strange quark stars

    CERN Document Server

    Martinez, A Perez; Paret, D Manreza

    2010-01-01

    We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in $\\beta$-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass-radius relation for magnetized strange quark stars is also obtained in this framework.

  17. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose–Volume Parameters and First Clinical Results

    International Nuclear Information System (INIS)

    Dimopoulos, Johannes C.A.; Schmid, Maximilian P.; Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Pötter, Richard

    2012-01-01

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45–50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model (α/β = 10 Gy for tumor; α/β = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV (± 1 standard deviation) at diagnosis was 45.3 (±30) cm 3 , and the mean GTV at brachytherapy was 10 (±14) cm 3 . The mean D90 for the HRCTV was 86 (±13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 (±20) Gy, 76 (±16) Gy, 70 (±9) Gy, and 60 (±9) Gy, respectively. After a median follow-up of 43 months (range, 19–87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and organs at risk are in a comparable

  18. Voxelwise comparison of perfusion parameters estimated using dynamic contrast enhanced (DCE) computed tomography and DCE-magnetic resonance imaging in locally advanced cervical cancer

    International Nuclear Information System (INIS)

    Kallehauge; Jesper; Nielsen, Thomas; Haack, Soeren

    2013-01-01

    Purpose: Dynamic contrast enhanced (DCE) imaging has gained interest as an imaging modality for assessment of tumor characteristics and response to cancer treatment. However, for DCE-magnetic resonance imaging (MRI) tissue contrast enhancement may vary depending on imaging sequence and temporal resolution. The aim of this study is to compare DCE-MRI to DCE-computed tomography (DCE-CT) as the gold standard. Material and methods: Thirteen patients with advanced cervical cancer were scanned once prior to chemo-radiation and during chemo-radiation with DCE-CT and -MRI in immediate succession. A total of 22 paired DCE-CT and -MRI scans were acquired for comparison. Kinetic modeling using the extended Tofts model was applied to both image series. Furthermore the similarity of the spatial distribution was evaluated using a G analysis. The correlation between the two imaging techniques was evaluated using Pe arson's correlation and the parameter means were compared using a Student's t-test (p trans (r = 0.9), flux rate constant k ep (r = 0.77), extracellular volume fraction v e (r = 0.58) and blood plasma volume fraction v p (r = 0.83). All quantitative parameters were found to be significantly different as estimated by DCE-CT and -MRI. The G analysis in normalized maps revealed that 45 % of the voxels failed to find a voxel with the corresponding value allowing for an uncertainty of 3 mm in position and 3 % in value (G 3,3 ). By reducing the criteria, the G-failure rates were: G 3,5 (37 % failure), G 3,10 (26% failure) and at G 3,15 (19 % failure). Conclusion: Good to excellent correlations but significant bias was found between DCE-CT and -MRI. Both the Pearson's correlation and the G analysis proved that the spatial information was similar when analyzing the two sets of DCE data using the extended Tofts model. Improvement of input function sampling is needed to improve kinetic quantification using DCE-MRI

  19. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose-Volume Parameters and First Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Johannes C.A. [Department of Radiation Oncology, Metropolitan Hospital, Athens (Greece); Schmid, Maximilian P., E-mail: maximilian.schmid@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria)

    2012-04-01

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and

  20. Data Analysis of Transient Energy Releases in the LHC Superconducting Dipole Magnets

    CERN Document Server

    Calvi, M; Bottura, L; Di Castro, M; Masi, A; Siemko, A

    2007-01-01

    Premature training quenches are caused by transient energy released within the LHC dipole magnet coils while it is energized. Voltage signals recorded across the magnet coils and on the so-called quench antenna carry information about these disturbances. The transitory events correlated to transient energy released are extracted making use of continuous wavelet transform. Several analyses are performed to understand their relevance to the so called training phenomenon. The statistical distribution of the signals amplitude, the number of events occurring at a given current level, the average frequency content of the events are the main parameters on which the analysis have been focalized. Comparisons among different regions of the magnet, among different quenches in the same magnet and among magnets made by different builders are reported. Conclusions about the efficiency of the raw data treatment and the relevance of the parameters developed with respect to the magnet global behavior are finally given.

  1. Calculation of magnetization curves and probability distribution for monoclinic and uniaxial systems

    International Nuclear Information System (INIS)

    Sobh, Hala A.; Aly, Samy H.; Yehia, Sherif

    2013-01-01

    We present the application of a simple classical statistical mechanics-based model to selected monoclinic and hexagonal model systems. In this model, we treat the magnetization as a classical vector whose angular orientation is dictated by the laws of equilibrium classical statistical mechanics. We calculate for these anisotropic systems, the magnetization curves, energy landscapes and probability distribution for different sets of relevant parameters and magnetic fields of different strengths and directions. Our results demonstrate a correlation between the most probable orientation of the magnetization vector, the system's parameters, and the external magnetic field. -- Highlights: ► We calculate magnetization curves and probability angular distribution of the magnetization. ► The magnetization curves are consistent with probability results for the studied systems. ► Monoclinic and hexagonal systems behave differently due to their different anisotropies

  2. Deep learning relevance

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Petersen, Casper

    2016-01-01

    train a Recurrent Neural Network (RNN) on existing relevant information to that query. We then use the RNN to "deep learn" a single, synthetic, and we assume, relevant document for that query. We design a crowdsourcing experiment to assess how relevant the "deep learned" document is, compared...... to existing relevant documents. Users are shown a query and four wordclouds (of three existing relevant documents and our deep learned synthetic document). The synthetic document is ranked on average most relevant of all....

  3. Fusion and technology: An introduction to the physics and technology of magnetic confinment fusion

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1984-01-01

    This book is an introduction covering all aspects of magnetic fusion and magnetic fusion technology. Physical property data relevant to fusion technology and a summary of fusion reactor design parameters are provided. Topics covered include: basic properties; equilibrium and transport confinement concepts; plasma heating; plasma wall interaction; magnetics; energy storage and transfer; interaction of radiation with matter; primary energy conversion and tritium breeding blanket; tritium and vacuum; and Fusion Reactor Design

  4. Magnetic Damping For Maglev

    Directory of Open Access Journals (Sweden)

    S. Zhu

    1998-01-01

    Full Text Available Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.

  5. Artificial magnetic metamaterial design by using spiral resonators

    OpenAIRE

    Baena, J.D.; Marqués Sillero, Ricardo; Medina Mena, Francisco; Martel Villagrán, Jesús

    2004-01-01

    A metallic planar particle, that will be called spiral resonator (SR), is introduced as a useful artificial atom for artificial magnetic media design and fabrication. A simple theoretical model which provides the most relevant properties and parameters of the SR is presented. The model is validated by both electromagnetic simulation and experiments. The applications of SR's include artificial negative magnetic permeability media (NMPM) and left-handed-media (LHM) design. The main advantages o...

  6. Design parameters for a 7.2 tesla bending magnet for a 1.5 GeV compact light source

    International Nuclear Information System (INIS)

    Green, M.A.; Madura, D.

    1995-06-01

    This report describes the design for a 7.2 tesla superconducting dipole magnet for a compact synchrotron light source. The proposed magnet is a Vobly type modified picture frame dipole that has the flux returned through unsaturated iron. In this magnet, The iron in the pole pieces is highly saturated, Separately powered coils around the pole pieces are used to direct the flux lines until the flux can be returned through the unsaturated iron. The proposed dipole will develop a uniform field over a region that is 80 mm high by 130 mm wide over a range of central induction from 0.4 T to almost 8 T. Each dipole for the compact light source will have a magnetic length of about 0.38 meters

  7. A simple model for localized-itinerant magnetic systems: crystal field effects

    International Nuclear Information System (INIS)

    Iannarella, L.; Silva, X.A. da; Guimarares, A.P.

    1989-01-01

    The magnetic behavior of a system consisting of localized electrons coupled to conduction electrons and submitted to an axial crystral field at T=0 K is ivestigated within the framework of the molecular field approximation. An analytical ionic magnetic state equation is deduced; it shows how the magnetization depends on the model parameters (exchange, crystal field, band occupation) and external magnetic field. A condition for the onset of spontaneous magnetic order is obtained and the ferro - and paramagnetic phases are studied. This study displays several features of real magnetic systems, including quenching or total suppression of the magnetic moments (depending on the relative value of the crystal field parameter) and exchange enhacement. The relevance of such model for the description of rare-earth intermetallic compounds is discussed. (author) [pt

  8. Extra high speed modified Lundell alternator parameters and open/short-circuit characteristics from global 3D-FE magnetic field solutions

    Science.gov (United States)

    Wang, R.; Demerdash, N. A.

    1992-06-01

    The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, is used for global 3D field analysis and machine performance computations under open-circuit and short-circuit conditions for an example 14.3 kVA modified Lundell alternator, whose magnetic field is of intrinsic 3D nature. The computed voltages and currents under these machine test conditions were verified and found to be in very good agreement with corresponding test data. Results of use of this modelling and computation method in the study of a design alteration example, in which the stator stack length of the example alternator is stretched in order to increase voltage and volt-ampere rating, are given here. These results demonstrate the inadequacy of conventional 2D-based design concepts and the imperative of use of this type of 3D magnetic field modelling in the design and investigation of such machines.

  9. Extra high speed modified Lundell alternator parameters and open/short-circuit characteristics from global 3D-FE magnetic field solutions

    Science.gov (United States)

    Wang, R.; Demerdash, N. A.

    1992-01-01

    The combined magnetic vector potential - magnetic scalar potential method of computation of 3D magnetic fields by finite elements, introduced in a companion paper, is used for global 3D field analysis and machine performance computations under open-circuit and short-circuit conditions for an example 14.3 kVA modified Lundell alternator, whose magnetic field is of intrinsic 3D nature. The computed voltages and currents under these machine test conditions were verified and found to be in very good agreement with corresponding test data. Results of use of this modelling and computation method in the study of a design alteration example, in which the stator stack length of the example alternator is stretched in order to increase voltage and volt-ampere rating, are given here. These results demonstrate the inadequacy of conventional 2D-based design concepts and the imperative of use of this type of 3D magnetic field modelling in the design and investigation of such machines.

  10. [Individual parameters of general low-frequency magnetic therapy as a possibility for improving the clinical efficacy of the combined treatment of patients with essential arterial hypertension].

    Science.gov (United States)

    Fedotov, V D; Maslov, A G; Lobkaeva, E P; Krylov, V N; Obukhova, E O

    2012-01-01

    A new approach is proposed for the choice of low-frequency magnetic therapy on an individual basis using the results of analysis of heart rhythm variability. The clinical efficiency of low-frequency magnetic therapy incorporated in the combined treatment of 65 patients aged between 25 and 45 years with essential arterial hypertension was estimated. The statistically significant positive effects of the treatment included normalization of blood pressure and characteristics of heart rhythm variability as well as resolution of clinical symptoms of vegetative dysregulation.

  11. Introduction to permanent magnets

    International Nuclear Information System (INIS)

    Zijlstra, H.

    1985-01-01

    Some general considerations concerning the application of permanent magnets are developed. The relevant magnet properties are discussed, with particular reference to Nd-Fe-B alloy. The author comes to the following conclusions; the air gap field B should be high, for high electrical efficiency; the magnet should face the air gap, for efficient use of the magnet material; the magnet material should therefore have a high remanence; and the new Nd-Fe-B magnet fits in nicely, having (potentially) the highest remanence ever reported in permanent magnets, combined with sufficient coercivity to sustain it

  12. Accurate computer-aided quantification of left ventricular parameters : experience in 1555 cardiac magnetic resonance studies from the Framingham Heart Study

    NARCIS (Netherlands)

    Hautvast, G.L.T.F.; Salton, C.J.; Chuang, M.L.; Breeuwer, M.; O'Donnel, C.J.; Manning, W.J.

    2011-01-01

    Quantitative analysis of short-axis functional cardiac magnetic resonance images can be performed using automatic contour detection methods. The resulting myocardial contours must be reviewed and possibly corrected, which can be time-consuming, particularly when performed across all cardiac phases.

  13. A new method for the continuous production of single dosed controlled release matrix systems based on hot-melt extruded starch: analysis of relevant process parameters and implementation of an in-process control.

    Science.gov (United States)

    Kipping, Thomas; Rein, Hubert

    2013-05-01

    In the present study, we evaluated a novel processing technique for the continuous production of hot-melt extruded controlled release matrix systems. A cutting technique derived from plastics industry, where it is widely used for cutting of cables and wires was adapted into the production line. Extruded strands were shaped by a rotary fly cutter. Special focus is laid on the development of a process analytical technology by evaluating signals obtained from the servo control of the rotary fly cutter. The intention is to provide a better insight into the production process and to offer the ability to detect small variations in process-variables. A co-rotating twin-screw extruder ZSE 27 HP-PH from Leistritz (Nürnberg, Germany) was used to plasticize the starch; critical extrusion parameters were recorded. Still elastic strands were shaped by a rotary fly-cutter type Dynamat 20 from Metzner (Neu-Ulm, Germany). Properties of the final products were analyzed via digital image analysis to point out critical parameters influencing the quality. Important aspects were uniformity of diameter, height, roundness, weight, and variations in the cutting angle. Stability of the products was measured by friability tests and by determining the crushing strength of the final products. Drug loading studies up to 70% were performed to evaluate the capacity of the matrix and to prove the technological feasibility. Changes in viscosities during API addition were analyzed by a Haake Minilab capillary rheometer. X-ray studies were performed to investigate molecular structures of the matrices. External shapes of the products were highly affected by die-swelling of the melt. Reliable reproducibility concerning uniformity of mass could be achieved even for high production rates (>2500cuts/min). Both mechanical strength and die-swelling of the products could be linked to the ratio of amylose to amylopectin. Formulations containing up to 70% of API could still be processed. Viscosity

  14. Tailoring magnetism by light-ion irradiation

    International Nuclear Information System (INIS)

    Fassbender, J; Ravelosona, D; Samson, Y

    2004-01-01

    Owing to their reduced dimensions, the magnetic properties of ultrathin magnetic films and multilayers, e.g. magnetic anisotropies and exchange coupling, often depend strongly on the surface and interface structure. In addition, chemical composition, crystallinity, grain sizes and their distribution govern the magnetic behaviour. All these structural properties can be modified by light-ion irradiation in an energy range of 5-150 keV due to the energy loss of the ions in the solid along their trajectory. Consequently the magnetic properties can be tailored by ion irradiation. Similar effects can also be observed using Ga + ion irradiation, which is the common ion source in focused ion beam lithography. Examples of ion-induced modifications of magnetic anisotropies and exchange coupling are presented. This review is limited to radiation-induced structural changes giving rise to a modification of magnetic parameters. Ion implantation is discussed only in special cases. Due to the local nature of the interaction, magnetic patterning without affecting the surface topography becomes feasible, which may be of interest in applications. The main patterning technique is homogeneous ion irradiation through masks. Focused ion beam and ion projection lithography are usually only relevant for larger ion masses. The creation of magnetic feature sizes below 50 nm is shown. In contrast to topographic nanostructures the surrounding area of these nanostructures can be left ferromagnetic, leading to new phenomena at their mutual interface. Most of the material systems discussed here are important for technological applications. The main areas are magnetic data storage applications, such as hard magnetic media with a large perpendicular magnetic anisotropy or patterned media with an improved signal to noise ratio and magnetic sensor elements. It will be shown that light-ion irradiation has many advantages in the design of new material properties and in the fabrication technology of

  15. An optimized magnet for magnetic refrigeration

    DEFF Research Database (Denmark)

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

    2010-01-01

    A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction...... of the actual magnet. The final design generates a peak value of 1.24 T, an average flux density of 0.9 T in a volume of 2 L using only 7.3 L of magnet, and has an average low flux density of 0.08 T also in a 2 L volume. The working point of all the permanent magnet blocks in the design is very close...... to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration....

  16. An optimized magnet for magnetic refrigeration

    International Nuclear Information System (INIS)

    Bjork, R.; Bahl, C.R.H.; Smith, A.; Christensen, D.V.; Pryds, N.

    2010-01-01

    A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction of the actual magnet. The final design generates a peak value of 1.24 T, an average flux density of 0.9 T in a volume of 2 L using only 7.3 L of magnet, and has an average low flux density of 0.08 T also in a 2 L volume. The working point of all the permanent magnet blocks in the design is very close to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration.

  17. Intra- and inter-observer reproducibility of global and regional magnetic resonance feature tracking derived strain parameters of the left and right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Björn, E-mail: bjoernschmidt1989@gmx.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Dick, Anastasia, E-mail: anastasia-dick@web.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Treutlein, Melanie, E-mail: melanie-treutlein@web.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Schiller, Petra, E-mail: petra.schiller@uni-koeln.de [Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Bunck, Alexander C., E-mail: alexander.bunck@uk-koeln.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Maintz, David, E-mail: david.maintz@uk-koeln.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany); Baeßler, Bettina, E-mail: bettina.baessler@uk-koeln.de [Department of Radiology, University Hospital of Cologne, Kerpener Str. 62, D-50937, Cologne (Germany)

    2017-04-15

    Highlights: • Left and right ventricular CMR feature tracking is highly reproducible. • The only exception is radial strain and strain rate. • Sample size estimations are presented as a practical reference for future studies. - Abstract: Objectives: To investigate the reproducibility of regional and global strain and strain rate (SR) parameters of both ventricles and to determine sample sizes for all investigated strain and SR parameters in order to generate a practical reference for future studies. Materials and methods: The study population consisted of 20 healthy individuals and 20 patients with acute myocarditis. Cine sequences in three horizontal long axis views and a stack of short axis views covering the entire left and right ventricle (LV, RV) were retrospectively analysed using a dedicated feature tracking (FT) software algorithm (TOMTEC). For intra-observer analysis, one observer analysed CMR images of all patients and volunteers twice. For inter-observer analysis, three additional blinded observers analysed the same datasets once. Intra- and inter-observer reproducibility were tested in all patients and controls using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation. Results: Intra-observer reproducibility of global LV strain and SR parameters was excellent (range of ICCs: 0.81–1.00), the only exception being global radial SR with a poor reproducibility (ICC 0.23). On a regional level, basal and midventricular strain and SR parameters were more reproducible when compared to apical parameters. Inter-observer reproducibility of all LV parameters was slightly lower than intra-observer reproducibility, yet still good to excellent for all global and regional longitudinal and circumferential strain and SR parameters (range of ICCs: 0.66–0.93). Similar to the LV, all global RV longitudinal and circumferential strain and SR parameters showed an excellent reproducibility, (range of ICCs: 0.75–0

  18. Intra- and inter-observer reproducibility of global and regional magnetic resonance feature tracking derived strain parameters of the left and right ventricle

    International Nuclear Information System (INIS)

    Schmidt, Björn; Dick, Anastasia; Treutlein, Melanie; Schiller, Petra; Bunck, Alexander C.; Maintz, David; Baeßler, Bettina

    2017-01-01

    Highlights: • Left and right ventricular CMR feature tracking is highly reproducible. • The only exception is radial strain and strain rate. • Sample size estimations are presented as a practical reference for future studies. - Abstract: Objectives: To investigate the reproducibility of regional and global strain and strain rate (SR) parameters of both ventricles and to determine sample sizes for all investigated strain and SR parameters in order to generate a practical reference for future studies. Materials and methods: The study population consisted of 20 healthy individuals and 20 patients with acute myocarditis. Cine sequences in three horizontal long axis views and a stack of short axis views covering the entire left and right ventricle (LV, RV) were retrospectively analysed using a dedicated feature tracking (FT) software algorithm (TOMTEC). For intra-observer analysis, one observer analysed CMR images of all patients and volunteers twice. For inter-observer analysis, three additional blinded observers analysed the same datasets once. Intra- and inter-observer reproducibility were tested in all patients and controls using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation. Results: Intra-observer reproducibility of global LV strain and SR parameters was excellent (range of ICCs: 0.81–1.00), the only exception being global radial SR with a poor reproducibility (ICC 0.23). On a regional level, basal and midventricular strain and SR parameters were more reproducible when compared to apical parameters. Inter-observer reproducibility of all LV parameters was slightly lower than intra-observer reproducibility, yet still good to excellent for all global and regional longitudinal and circumferential strain and SR parameters (range of ICCs: 0.66–0.93). Similar to the LV, all global RV longitudinal and circumferential strain and SR parameters showed an excellent reproducibility, (range of ICCs: 0.75–0

  19. The temperature dependence of the Moessbauer parameters and the magnetic properties of the RFe2 (R = Y or rare earth) compounds

    International Nuclear Information System (INIS)

    Barb, D.; Burzo, E.; Morariu, M.

    1975-01-01

    Temperature dependence of hyperfine fields and quadrupole splitting is presented for the following compounds: DyFe 2 , HoFe 2 , ErFe 2 , TmFe 2 , and YFe 2 . Moessbauer studies were made by an ERLON-type equipment. A 57 Co in Cu source was employed. Data were stored for a velocity range of +- 10 mm/sec using a DIDAC-4000 analyzer. The spectra were fitted by a IBM-370 type computer using a FORTRAN programme. The measurements were carried out in a temperature range from 77 K to the Curie temperature. Quadrupole splitting for all compounds varied continuously with temperature up to the Curie temperature where a sudden change was observed. The magnetic behaviour of the YFe 2 and DyFe 2 compounds was analyzed. Moessbauer results were discussed in connection with the magnetic data. (Z.S.)

  20. Magnetic elements for switching magnetization magnetic force microscopy tips

    International Nuclear Information System (INIS)

    Cambel, V.; Elias, P.; Gregusova, D.; Martaus, J.; Fedor, J.; Karapetrov, G.; Novosad, V.

    2010-01-01

    Using combination of micromagnetic calculations and magnetic force microscopy (MFM) imaging we find optimal parameters for novel magnetic tips suitable for switching magnetization MFM. Switching magnetization MFM is based on two-pass scanning atomic force microscopy with reversed tip magnetization between the scans. Within the technique the sum of the scanned data with reversed tip magnetization depicts local atomic forces, while their difference maps the local magnetic forces. Here we propose the design and calculate the magnetic properties of tips suitable for this scanning probe technique. We find that for best performance the spin-polarized tips must exhibit low magnetic moment, low switching fields, and single-domain state at remanence. The switching field of such tips is calculated and optimum shape of the Permalloy elements for the tips is found. We show excellent correspondence between calculated and experimental results for Py elements.

  1. Nuclear Magnetic Resonance: new applications in the quantification and assessment of polysaccharide-based vaccine intermediates

    International Nuclear Information System (INIS)

    Garrido, Raine; Velez, Herman; Verez, Vicente

    2013-01-01

    Nuclear Magnetic Resonance has become the choice for structural studies, identity assays and simultaneous quantification of active pharmaceutical ingredient of different polysaccharide-based vaccine. In the last two decades, the application of quantitative Nuclear Magnetic Resonance had an increasing impact to support several quantification necessities. The technique involves experiments with several modified parameters in order to obtain spectra with quantifiable signals. The present review is supported by some recent relevant reports and it discusses several applications of NMR in carbohydrate-based vaccines. Moreover, it emphasizes and describes several parameters and applications of quantitative Nuclear Magnetic Resonance

  2. Magnetic starspots

    International Nuclear Information System (INIS)

    Jahn, K.; Stepien, K.

    1984-01-01

    Models of large magnetic starspots with an axisymmetric untwisted magnetic field on late type stars are discussed. It is assumed that the magnetic field reduces the efficiency of convection inside the spot. A unique relation between the stellar mass and the difference of effective temperatures of the spot and the surrounding photosphere is adopted from observations. It is equivalent to the reduction of a s (the mixing length theory parameter) inside the spot to the value 0.15 independently of the stellar mass. The surface magnetic field of large spots covering a considerable part of the stellar surface is a decreasing function of the magnetic flux. Hence a coverage of a star by magnetic regions rapidly increases as a function of the magnetic flux in a narrow range of fluxes. This behaviour can explain the Vaughan-Preston gap. Recent observations of magnetic fields on G and K type stars are in a good agreement with our predictions. 35 refs., 3 figs., 4 tabs. (author)

  3. Making Deferred Taxes Relevant

    NARCIS (Netherlands)

    Brouwer, Arjan; Naarding, Ewout

    2018-01-01

    We analyse the conceptual problems in current accounting for deferred taxes and provide solutions derived from the literature in order to make International Financial Reporting Standards (IFRS) deferred tax numbers value-relevant. In our view, the empirical results concerning the value relevance of

  4. Parsimonious relevance models

    NARCIS (Netherlands)

    Meij, E.; Weerkamp, W.; Balog, K.; de Rijke, M.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    We describe a method for applying parsimonious language models to re-estimate the term probabilities assigned by relevance models. We apply our method to six topic sets from test collections in five different genres. Our parsimonious relevance models (i) improve retrieval effectiveness in terms of

  5. Reproducible synthesis of YBCO high-temperature superconducting ceramics (step 1) and parameters and optimized design of superconducting Magnetic Bearings (step 2). Final report

    International Nuclear Information System (INIS)

    Floegel-Delor, U.; Rothfeld, R.; Wippich, D.; Werfel, F.

    1999-11-01

    A method for selective and economically efficient production of large HTSL bodies on the basis of polycrystalline YBCO material (CCG - CeramoCrystalGrowth) was developed which does not require nucleation and achieves macroscopic grain orientation and high intrinsic current densities of 30 A/cm (intrinsic field). Formed bodies up to a diameter of 150 mm and a mass of 2 kg were grown. In the second stage, frictionless and contactless magnetic bearings with HTS were investigated. They were found to have advantages over the current technologies, e.g. extremely high speed and bearing of unbalanced rotors [de

  6. Changing environmental conditions in recent past — Reading through the study of geochemical characteristics, magnetic parameters and sedimentation rate of mudflats, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.T.; Nayak, G.N.; Fernandes, L.L.; Borole, D.V.; Basavaiah, N.

    ), +91 982 ak@unigoa.ac.in (G.N. Nayak). rights reserved.nt past — Reading through agnetic parameters and t coast of India a, D.V. Borole c, N. Basavaiah d matology, Palaeoecology ev ie r .com/ locate /pa laeorine sedimentation is usually a reasonably...

  7. Quantization of physical parameters

    International Nuclear Information System (INIS)

    Jackiw, R.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

    1984-01-01

    Dynamical models are described with parameters (mass, coupling strengths) which must be quantized for quantum mechanical consistency. These and related topological ideas have physical application to phenomenological descriptions of high temperature and low energy quantum chromodynamics, to the nonrelativistic dynamics of magnetic monopoles, and to the quantum Hall effect. (author)

  8. Scanning SQUID microscopy of a ferromanganese crust from the northwestern Pacific: Submillimeter scale magnetostratigraphy as a new tool for age determination and mapping of environmental magnetic parameters

    Science.gov (United States)

    Noguchi, A.; Oda, H.; Yamamoto, Y.; Usui, A.; Sato, M.; Kawai, J.

    2017-06-01

    Ferromanganese crusts record long-term deep-sea environmental changes. Thus, providing their reliable high-resolution age models is important. We applied a magnetostratigraphic technique to estimate the growth rate of a ferromanganese crust using scanning SQUID (superconducting quantum interference device) microscope (SSM). SSM is designed to map the magnetic field across thin sections with submillimeter resolution. The crust sample was taken from the Takuyo-Daigo Seamount, northwestern Pacific, and recorded a limited supply of dust and sediment from continents. After drift correction and removal of spike noises, the magnetic field values were stacked within the areas of high signal-to-noise ratios. By correlating the obtained profiles with a standard geomagnetic polarity timescale, we obtained an average growth rate of 3.37 ± 0.06 mm/Ma, which is consistent with that obtained by 10Be/9Be geochronology (2.93 ± 0.15 mm/Ma). S ratio mapping shows low values after 3 Ma, associated with voids between columnar structures.

  9. Magnetic properties of diluted magnetic semiconductors

    NARCIS (Netherlands)

    Jonge, de W.J.M.; Swagten, H.J.M.

    1991-01-01

    A review will be given of the magnetic characteristics of diluted magnetic semiconductors and the relation with the driving exchange mechanisms. II–VI as well as IV–VI compounds will be considered. The relevance of the long-range interaction and the role of the carrier concentration will be

  10. Relevância do estado de hidratação na interpretação de parâmetros nutricionais em diálise peritoneal Relevance of hydration status on the interpretation of nutritional parameters in peritoneal dialysis

    Directory of Open Access Journals (Sweden)

    Aline de Araujo Antunes

    2011-02-01

    determinants of the hydration status of chronic peritoneal dialysis patients and investigated the effects of fluid overload on their nutritional status. METHODS: A cross-sectional study was conducted in 2006 to evaluate 27 chronic peritoneal dialysis patients from the Dialysis Center of the Medical School Hospital of Botucatu (SP, considering clinical, dialytic, laboratory, anthropometric and bioimpedance parameters. A linear multiple regression model was used to evaluate the influence of these parameters on hydration status. The sample was stratified according to hydration status, given by the ratio between extracellular water and total body water (0.47 for males and 0.52 for females, obtained by bioelectrical impedance. Analysis of covariance, Mann-Whitney test, chi-square test, and Fisher's exact test were used for making comparisons. The significance level was set at 5% (p≤0.05. RESULTS: Patients with greater urine volume and receiving automatic dialysis presented better hydration status. Patients with higher fluid overload, compared with those with lower overload, presented lower phase angle (M=4.2, SD=0.9 vs. M=5.7, SD=0.7º; p=0.006, lower albumin levels (M=3.06, SD=0.46 vs. M=3.55, SD=0.52g/dL; p=0.05, and higher percentage of triceps skinfold thickness (M=75.3, SD=36.9 vs. M= 92.1, SD=56.9; p=0.058. No other anthropometric differences were observed. CONCLUSION: Low levels of albumin and phase angle in patients with higher fluid overload were not related to worse nutritional status. This result suggests that one must consider the set of variables obtained by many methods and relate and interpret them comprehensively in order to obtain a reliable nutritional diagnosis of patients with fluid overload.

  11. Magnetic properties of lithium rare-earth fluorides: Ferromagnetism in LiErF4 and LiHoF4 and crystal-field parameters at the rare-earth and Li sites

    DEFF Research Database (Denmark)

    Hansen, P. E.; Johansson, Torben; Nevald, Rolf

    1975-01-01

    Single crystals of LiErF4 and LiHoF4 have been grown and their magnetic properties measured from 1.3 K to 300 K. LiHoF4 turned out to be a nearly ideal Ising ferromagnet with TC=1.30±0.05 K and a saturation magnetization along the crystalline c axis of (6.98±0.02)μB. In LiErF4 no ordering...... was observed, but extrapolation indicates that below 0.5 K it will be ferromagnetic with the magnetic moments in the crytalline ab plane. From the susceptibilities the crystal-field parameters Bnm with (n, m)=(2, 0), (4, 0), (4, 4), (6, 0), (6, 4) have been extracted giving for Er3+ in LiErF4: 430., -985......., 1185., -5., 740.+i135. (cm-1) and for Ho3+ in LiHoF4: 470., -825., 1050., -10., 760.+i150 (cm-1). The exchange constants were found to be small compared to the dipole interactions. Furthermore the 7Li NMR spectra have been obtained in these materials as well as in LiTbF4 thereby determining the second...

  12. Effect of doping with magnetic 3D-elements on the thermal fluctuations and critical parameters of CaLaBaCu{sub 3-x}(Ni,Co){sub x}O{sub 7-{delta}} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Rojas Sarmiento, M.P.; Landinez Tellez, D.A. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia); Roa-Rojas, J. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 14490, Bogota DC (Colombia)], E-mail: jroar@unal.edu.co

    2008-07-15

    Systematic measurements on conductivity fluctuation in the CaLaBaCu{sub 3-x}(Ni,Co){sub x}O{sub 7-{delta}} system are reported. Samples with x=0, 0.03, 0.06, 0.09, 0.12, 0.15 and 0.18 were prepared by the standard solid-state reaction recipe. Results of resistivity measurements reveal a linear-like decreasing of the critical temperature T{sub c} with progressive substitution of magnetic elements Ni and Co into the Cu crystallographic sites. From the fluctuation analysis, above and close to T{sub c}, we found the occurrence of three- and two-dimensional Gaussian fluctuation regimes. Closer to T{sub c}, a genuinely critical regime is observed. On the Ginzburg-Landau formalism, from the reduced temperature of the three-dimensional Gaussian region and the mean field critical temperature, we have experimentally obtained the Ginzburg number for the CaLaBaCu{sub 3-x}(Ni,Co){sub x}O{sub 7-{delta}} material. Then, critical magnetic field, critical current density and the jump in the specific heat at the critical temperature are calculated. Critical parameters are strongly affected by the doping with magnetic ions.

  13. Effect of doping with magnetic 3D-elements on the thermal fluctuations and critical parameters of CaLaBaCu3-x(Ni,Co)xO7-δ superconductors

    International Nuclear Information System (INIS)

    Rojas Sarmiento, M.P.; Landinez Tellez, D.A.; Roa-Rojas, J.

    2008-01-01

    Systematic measurements on conductivity fluctuation in the CaLaBaCu 3-x (Ni,Co) x O 7-δ system are reported. Samples with x=0, 0.03, 0.06, 0.09, 0.12, 0.15 and 0.18 were prepared by the standard solid-state reaction recipe. Results of resistivity measurements reveal a linear-like decreasing of the critical temperature T c with progressive substitution of magnetic elements Ni and Co into the Cu crystallographic sites. From the fluctuation analysis, above and close to T c , we found the occurrence of three- and two-dimensional Gaussian fluctuation regimes. Closer to T c , a genuinely critical regime is observed. On the Ginzburg-Landau formalism, from the reduced temperature of the three-dimensional Gaussian region and the mean field critical temperature, we have experimentally obtained the Ginzburg number for the CaLaBaCu 3-x (Ni,Co) x O 7-δ material. Then, critical magnetic field, critical current density and the jump in the specific heat at the critical temperature are calculated. Critical parameters are strongly affected by the doping with magnetic ions

  14. Random magnetism

    International Nuclear Information System (INIS)

    Tahir-Kheli, R.A.

    1975-01-01

    A few simple problems relating to random magnetic systems are presented. Translational symmetry, only on the macroscopic scale, is assumed for these systems. A random set of parameters, on the microscopic scale, for the various regions of these systems is also assumed. A probability distribution for randomness is obeyed. Knowledge of the form of these probability distributions, is assumed in all cases [pt

  15. Study on the technical parameters of two different systems of RIA performed with solid-phase antibody test tubes prepared with magnetic microparticle covalence conjagation or conventional physical absorption

    International Nuclear Information System (INIS)

    Chen Zhiqiang; Wang Chengmin; Tang Baojun

    2007-01-01

    Objective: To investigate a new method of preparation of solid-phase antibody with flurorescein isothioeynate (FITC)-anti FITC magnetic nanoparticles system (for FT 3 and TSH). Methods: FT 3 and TSH monoclonal antibody IgC was la- belied with FITC. Anti-FITC magnetic mieroparticles was prepared and conjugated with the FITC labelled antibody to form the solid - phase coated test tube for RIA. Solid-phase test tube prepared with the conventional physical absorption method was also used for RIA and the technical parameters of the two systems were compared. Results: For FT 3 , the sensitivity was 0.18pmol/L with the new method and 0.43pmol/L with the conventional method. Other parameters were; intra-CV, 8.96% vs 16.26%; inter-CV, 15.25% vs 18.83%, correlation with PR method r=0.9825 vs r=0.9102. For TSH, sensitivity was 0.061 μIU/ml vs 0.04 μ IU/ml, intra- CV, 7.6% vs 6.92%, inter-CV, 8.55% vs 14.23%, correlation between the new and conventional method, r=0. 9987. TSH RIA was especially rapid with the new technic: 79 min vs 190 min. Conclusion: For FT 3 and TSH RIA, the new method takes much less time with increased homogeniety. (authors)

  16. Spectroscopic and thermal properties of uranium relevant to atomic schemes for laser isotope separation

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Pandey, P.L.

    1980-01-01

    Spectroscopic data on uranium atom and thermal properties of uranium relevant to atomic schemes for laser isotope separation have been presented in this report. All the relevant spectroscopic data reported in literature so far, as well as some other parameters like photo-absorption cross sections, branching ratios, effects of magnetic and electric fields, evaluated using the existing data, have been presented here. Among the thermal properties, parameters like vapour pressure and number densities for U/Liquid U, U/URe 2 and U/UP systems, partition function, percentage population distribution in energy levels, thermal ionisation and velocities of uranium atom have been presented at different temperatures. Different possible collision processes are mentioned and cross-sections of U-U + charge-exchange and U + + e radiative recombination processes have been also evaluated. (author)

  17. Lower hybrid current drive at ITER-relevant high plasma densities

    International Nuclear Information System (INIS)

    Cesario, R.; Amicucci, L.; Cardinali, A.; Castaldo, C.; Marinucci, M.; Panaccione, L.; Pericoli-Ridolfini, V.; Tuccillo, A. A.; Tudisco, O.; Calabro, G.

    2009-01-01

    Recent experiments indicated that a further non-inductive current, besides bootstrap, should be necessary for developing advanced scenario for ITER. The lower hybrid current drive (LHCD) should provide such tool, but its effectiveness was still not proved in operations with ITER-relevant density of the plasma column periphery. Progress of the LH deposition modelling is presented, performed considering the wave physics of the edge, and different ITER-relevant edge parameters. Operations with relatively high edge electron temperatures are expected to reduce the LH || spectral broadening and, consequently, enabling the LH power to propagate also in high density plasmas ( || is the wavenumber component aligned to the confinement magnetic field). New results of FTU experiments are presented, performed by following the aforementioned modeling: they indicate that, for the first time, the LHCD conditions are established by operating at ITER-relevant high edge densities.

  18. The association of trunk muscle cross-sectional area and magnetic resonance image parameters with isokinetic and psychophysical lifting strength and static back muscle endurance in men.

    Science.gov (United States)

    Gibbons, L E; Latikka, P; Videman, T; Manninen, H; Battié, M C

    1997-10-01

    The relationship between trunk muscle morphology as measured on transverse magnetic resonance images and isokinetic lifting, psychophysical lifting, and static back muscle endurance testing was examined in 110 men, ages 35-67 years (mean, 48 years), who had been chosen based on their exposure to a wide variety of occupational and leisure-time physical activities. The computed T2-relaxation times and the T2-weighted and proton density-weighted signal intensities of the erector spinae, quadratus lumborum, and psoas major muscles had almost no association with any of the strength tests. The cross-sectional areas of the muscles had good correlations with isokinetic lifting strength (r = 0.46-0.53). They did not correlate well with psychophysical lifting and static back muscle endurance. Other characteristics or neurological or psychological factors may have more influence on those tests.

  19. Next-Step scientific objectives, targets, and parameters for reversed-field-pinch (RFP) magnetic fusion energy (MFE) systems: Preliminary thoughts

    International Nuclear Information System (INIS)

    Krakowski, R.A.; Bathke, C.G.; DiMarco, J.N.; Miller, R.L.; Werley, K.A.

    1993-01-01

    The purpose of this document is the quantitative definition of objectives, targets, and parameters of the Next-Step device to follow the present RFX experiment; this device is given the name RFXNS. Although developed over five years ago, much of the material distilled into the 1988 RFP tactical plan is useful in establishing the goals and parameters of RFXNS. This earlier plan established tentative parameters of an RFP next step based on: predictions of RFP ignition and commercial-reactor devices; and the assumed successful operation of highly complementary RFP experiments RFX and ZTH/CPRF. Programmatic changes and evolution that have occurred since 1988 strongly impact the role and characteristics of an RFXNS: the Los Alamos ZTH/CPRF project and fusion program was terminated in mid-construction for reasons of MFE cost savings and concept focusing; great progress has been made in launching ITER; and reactor projections for the tokamak have increased in detail and variety, but not in commercial promise and competitiveness. A brief status of and perspective from each of the above three points is necessary before the key issues and their implementation to form the basis of the RFXNS definition are given

  20. Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

    Energy Technology Data Exchange (ETDEWEB)

    Han, Eunkyu; Muirhead, Philip S. [Department of Astronomy and Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Swift, Jonathan J. [The Thacher School, 5025 Thacher Road Ojai, CA 93023 (United States); Baranec, Christoph; Atkinson, Dani [Institute for Astronomy, University of Hawaiì at Mānoa, Hilo, HI 96720-2700 (United States); Law, Nicholas M. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States); Riddle, Reed [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Mace, Gregory N. [McDonald Observatory and The University of Texas, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); DeFelippis, Daniel, E-mail: eunkyuh@bu.edu [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

    2017-09-01

    Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star’s faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtained with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii.

  1. Study of relevant parameters of GEM-based detectors

    CERN Document Server

    Croci, Gabriele; Sauli, Fabio; Ragazzi, S

    2007-01-01

    The Gas Electron Multiplier consist of a thin Kapton insulating (50 $\\mu$m) foil copper-clad on both sides and perforated by a high density, regular matrix of holes (around 100 per square millimeter). Typically the distance between holes (pitch) is 140 $\\mu$m and diameters of about 70 $\\mu$m. The mesh is realised by conventional photolitographic methods as used for the fabrication of multi-layer board. Upon application of a potential difference between the GEM electrodes, a high dipole field develops in the holes focusing the field lines between the drift electrode and the readout element. Electron drift along the channel and the charge is amplified by a factor that depends on the field density and the length of the channel. Owing to their excellent position resolution and rate capability GEM-based detector are very suitable to be used in different applications: from the high energy physics to the medical field. The GEM temporal and rate gain stability was studied and it was discovered that the gain variation...

  2. Validation of the GROMOS force-field parameter set 45A3 against nuclear magnetic resonance data of hen egg lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Soares, T. A. [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland); Daura, X. [Universitat Autonoma de Barcelona, InstitucioCatalana de Recerca i Estudis Avancats and Institut de Biotecnologia i Biomedicina (Spain); Oostenbrink, C. [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland); Smith, L. J. [University of Oxford, Oxford Centre for Molecular Sciences, Central Chemistry Laboratory (United Kingdom); Gunsteren, W. F. van [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland)], E-mail: wfvgn@igc.phys.chem.ethz.ch

    2004-12-15

    The quality of molecular dynamics (MD) simulations of proteins depends critically on the biomolecular force field that is used. Such force fields are defined by force-field parameter sets, which are generally determined and improved through calibration of properties of small molecules against experimental or theoretical data. By application to large molecules such as proteins, a new force-field parameter set can be validated. We report two 3.5 ns molecular dynamics simulations of hen egg white lysozyme in water applying the widely used GROMOS force-field parameter set 43A1 and a new set 45A3. The two MD ensembles are evaluated against NMR spectroscopic data NOE atom-atom distance bounds, {sup 3}J{sub NH{alpha}} and {sup 3}J{sub {alpha}}{sub {beta}} coupling constants, and {sup 1}5N relaxation data. It is shown that the two sets reproduce structural properties about equally well. The 45A3 ensemble fulfills the atom-atom distance bounds derived from NMR spectroscopy slightly less well than the 43A1 ensemble, with most of the NOE distance violations in both ensembles involving residues located in loops or flexible regions of the protein. Convergence patterns are very similar in both simulations atom-positional root-mean-square differences (RMSD) with respect to the X-ray and NMR model structures and NOE inter-proton distances converge within 1.0-1.5 ns while backbone {sup 3}J{sub HN{alpha}}-coupling constants and {sup 1}H- {sup 1}5N order parameters take slightly longer, 1.0-2.0 ns. As expected, side-chain {sup 3}J{sub {alpha}}{sub {beta}}-coupling constants and {sup 1}H- {sup 1}5N order parameters do not reach full convergence for all residues in the time period simulated. This is particularly noticeable for side chains which display rare structural transitions. When comparing each simulation trajectory with an older and a newer set of experimental NOE data on lysozyme, it is found that the newer, larger, set of experimental data agrees as well with each of the

  3. Validation of the GROMOS force-field parameter set 45A3 against nuclear magnetic resonance data of hen egg lysozyme

    International Nuclear Information System (INIS)

    Soares, T. A.; Daura, X.; Oostenbrink, C.; Smith, L. J.; Gunsteren, W. F. van

    2004-01-01

    The quality of molecular dynamics (MD) simulations of proteins depends critically on the biomolecular force field that is used. Such force fields are defined by force-field parameter sets, which are generally determined and improved through calibration of properties of small molecules against experimental or theoretical data. By application to large molecules such as proteins, a new force-field parameter set can be validated. We report two 3.5 ns molecular dynamics simulations of hen egg white lysozyme in water applying the widely used GROMOS force-field parameter set 43A1 and a new set 45A3. The two MD ensembles are evaluated against NMR spectroscopic data NOE atom-atom distance bounds, 3 J NHα and 3 J αβ coupling constants, and 1 5N relaxation data. It is shown that the two sets reproduce structural properties about equally well. The 45A3 ensemble fulfills the atom-atom distance bounds derived from NMR spectroscopy slightly less well than the 43A1 ensemble, with most of the NOE distance violations in both ensembles involving residues located in loops or flexible regions of the protein. Convergence patterns are very similar in both simulations atom-positional root-mean-square differences (RMSD) with respect to the X-ray and NMR model structures and NOE inter-proton distances converge within 1.0-1.5 ns while backbone 3 J HNα -coupling constants and 1 H- 1 5N order parameters take slightly longer, 1.0-2.0 ns. As expected, side-chain 3 J αβ -coupling constants and 1 H- 1 5N order parameters do not reach full convergence for all residues in the time period simulated. This is particularly noticeable for side chains which display rare structural transitions. When comparing each simulation trajectory with an older and a newer set of experimental NOE data on lysozyme, it is found that the newer, larger, set of experimental data agrees as well with each of the simulations. In other words, the experimental data converged towards the theoretical result

  4. Culturally Relevant Cyberbullying Prevention

    OpenAIRE

    Phillips, Gregory John

    2017-01-01

    In this action research study, I, along with a student intervention committee of 14 members, developed a cyberbullying intervention for a large urban high school on the west coast. This high school contained a predominantly African American student population. I aimed to discover culturally relevant cyberbullying prevention strategies for African American students. The intervention committee selected video safety messages featuring African American actors as the most culturally relevant cyber...

  5. Overview and recent progress of the Magnetized Shock Experiment (MSX)

    Science.gov (United States)

    Weber, T. E.; Intrator, T. P.; Smith, R. J.; Hutchinson, T. M.; Boguski, J. C.; Sears, J. A.; Swan, H. O.; Gao, K. W.; Chapdelaine, L. J.; Winske, D.; Dunn, J. P.

    2013-10-01

    The Magnetized Shock Experiment (MSX) has been constructed to study the physics of super-Alfvènic, supercritical, magnetized shocks. Exhibiting transitional length and time scales much smaller than can be produced through collisional processes, these shocks are observed to create non-thermal distributions, amplify magnetic fields, and accelerate particles to relativistic velocities. Shocks are produced through the acceleration and subsequent stagnation of Field Reversed Configuration (FRC) plasmoids against a high-flux magnetic mirror with a conducting boundary or a plasma target with embedded field. Adjustable shock velocity, density, and magnetic geometry (B parallel, perpendicular, or oblique to k) provide unique access to a wide range of dimensionless parameters relevant to astrophysical shocks. Information regarding the experimental configuration, diagnostics suite, recent simulations, experimental results, and physics goals will be presented. This work is supported by DOE OFES and NNSA under LANS contract DE-AC52-06NA25369 Approved for Public Release: LA-UR-13-24859.

  6. Magnetization reversal in ultrashort magnetic field pulses

    International Nuclear Information System (INIS)

    Bauer, M.; Lopusnik, R.; Fassbender, J.; Hillebrands, B.

    2000-01-01

    We report the switching properties of a thin magnetic film subject to an ultrashort, laterally localized magnetic field pulse, obtained by numerical investigations. The magnetization distribution in the film is calculated on a grid assuming Stoner-like coherent rotation within the grid square size. Perpendicularly and in-plane magnetized films exhibit a magnetization reversal due to a 4 ps magnetic field pulse. Outside the central region the pulse duration is short compared to the precession period. In this area the evolution of the magnetization during the field pulse does not depend strongly on magnetic damping and/or pulse shape. However, the final magnetization distribution is affected by the magnetic damping. Although the pulse duration is short compared to the precession period, the time needed for the relaxation of the magnetization to the equilibrium state is rather large. The influence of the different magnetic anisotropy contributions and the magnetic damping parameter enters into the magnetization reversal process. Comparing the case of perpendicular anisotropy with different kinds of in-plane anisotropies, a principal difference is found due to the symmetry of the shape anisotropy with respect to the anisotropy in question

  7. Impact of the beam pipe design on the operation parameters of the superconducting magnets for the SIS 100 synchrotron of the FAIR project

    International Nuclear Information System (INIS)

    Fischer, E; Schnizer, P; Mierau, A; Shim, S; Heil, C; Schnizer, B

    2010-01-01

    The SIS 100 accelerator of the Facility for Antiprotons and Ion Research (FAIR) at GSI Darmstadt will be the world's second fast ramped synchrotron utilising superconducting magnets in heavy ion research facilities. The request for high current Uranium beams requires vacuum of extremely high quality that can be achieved in long term operation only by cold vacuum chambers acting as a cryogenic pump. Its mechanical stable design options are strongly limited by AC loss generation and field distortion problems. Previous R and D indicated that cooling tubes, keeping the vacuum chamber below 15 K, create large additional eddy currents and thus deteriorate the field with a sextupole. This effect is most dominant at the start of the ramp. The ramp rate of the correctors is limited by the maximum available voltage and as by the heat created on the ramp up and the cooling efficiency of the Nuclotron-type cable. Thus we investigate different means to simplify the vacuum chamber design keeping its temperature below 15 K in the area where the highest suction pumping is required with alternative cooling methods as well as on the compensation margin the sextupole correctors can provide. This work was partly supported by the BMBF.

  8. Electronic structure, magnetic properties, and microstructural analysis of thiol-functionalized Au nanoparticles: role of chemical and structural parameters in the ferromagnetic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, Estefania; Munoz-Marquez, Miguel A., E-mail: miguel.angel@icmse.csic.e [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain); Fernandez-Pinel, Enrique; Crespo, Patricia; Hernando, Antonio [Instituto de Magnetismo Aplicado (UCM-ADIF-CSIC) (Spain); Fernandez, Asuncion [Instituto de Ciencia de Materiales de Sevilla (CSIC-US) (Spain)

    2008-12-15

    Gold nanoparticles (NPs) have been stabilized with a variety of thiol-containing molecules in order to change their chemical and physical properties; among the possible capping systems, alkane chains with different lengths, a carboxylic acid and a thiol-containing biomolecule (tiopronin) have been selected as protecting shells for the synthesized NPs; the NPs solubility in water or organic solvents is determined by the protecting molecule. A full microstructural characterization of these NPs is presented in the current research work. It has been shown that NPs capped with alkanethiol chains have a marked ferromagnetic behaviour which might also be dependent on the chain length. The simultaneous presence of Au-Au and Au-S bonds together with a reduced particle diameter, and the formation of an ordered monolayer protective shell, have proved to be key parameters for the ferromagnetic-like behaviour exhibited by thiol-functionalized gold NPs.

  9. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  10. A quantitative analysis of the diurnal evolution of Ionospheric Alfvén resonator magnetic resonance features and calculation of changing IAR parameters

    Directory of Open Access Journals (Sweden)

    S. R. Hebden

    2005-07-01

    Full Text Available Resonance features of the Ionospheric Alfvén Resonator (IAR can be observed in pulsation magnetometer data from Sodankylä, Finland using dynamic spectra visualizations. IAR resonance features were identified on 13 of 30 days in October 1998, with resonance structures lasting for 3 or more hours over 10 intervals. The diurnal evolution of the harmonic features was quantified for these 10 intervals using a manual cursor-clicking technique. The resonance features displayed strong linear relationships between harmonic frequency and harmonic number for all of the time intervals studied, enabling a homogeneous cavity model for the IAR to be adopted to interpret the data. This enabled the diurnal variation of the effective size of the IAR to be obtained for each of the 10 time intervals. The average effective size was found to be 530 km, and to have an average variation of 32% over each time interval: small compared to the average variation in Alfvén velocity of 61%. Thus the diurnal variation of the harmonics is chiefly caused by the changing plasma density within the IAR due to changing insolation. This study confirms Odzimek (2004 that the dominating factor affecting the IAR eigenfrequencies is the variation in the Alfvén velocity at the F-layer ion-density peak, with the changing IAR size affecting the IAR eigenfrequencies to a smaller extent. Another IAR parameter was derived from the analysis of the IAR resonance features associated with the phase matching structure of the standing waves in the IAR. This parameter varied over the time intervals studied by 20% on average, possibly due to changing ionospheric conductivity. Keywords. Ionosphere (Auroral ionosphere;Wave propagation – Radio science (Electromagnetic noise and interference

  11. Parameter Estimation

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian

    2011-01-01

    of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set......In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....

  12. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  13. Random magnetism

    International Nuclear Information System (INIS)

    Tsallis, C.

    1980-03-01

    The 'ingredients' which control a phase transition in well defined system as well as in random ones (e.g. random magnetic systems) are listed and discussed within a somehow unifying perspective. Among these 'ingredients' we find the couplings and elements responsible for the cooperative phenomenon, the topological connectivity as well as possible topological incompatibilities, the influence of new degrees of freedom, the order parameter dimensionality, the ground state degeneracy and finally the 'quanticity' of the system. The general trends, though illustrated in magnetic systems, essentially hold for all phase transitions, and give a basis for connection of this area with Field theory, Theory of dynamical systems, etc. (Author) [pt

  14. Random magnetism

    International Nuclear Information System (INIS)

    Tsallis, C.

    1981-01-01

    The 'ingredients' which control a phase transition in well defined systems as well as in random ones (e.q. random magnetic systems) are listed and discussed within a somehow unifying perspective. Among these 'ingredients' the couplings and elements responsible for the cooperative phenomenon, the topological connectivity as well as possible topological incompatibilities, the influence of new degrees of freedom, the order parameter dimensionality, the ground state degeneracy and finally the 'quanticity' of the system are found. The general trends, though illustrated in magnetic systems, essentially hold for all phase transitions, and give a basis for connection of this area with Field theory, Theory of dynamical systems, etc. (Author) [pt

  15. Superconducting magnet

    Science.gov (United States)

    1985-01-01

    Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

  16. Is Information Still Relevant?

    Science.gov (United States)

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  17. Normal ranges and test-retest reproducibility of flow and velocity parameters in intracranial arteries measured with phase-contrast magnetic resonance imaging

    International Nuclear Information System (INIS)

    Correia de Verdier, Maria; Wikstroem, Johan

    2016-01-01

    The purpose of the present study was to investigate normal ranges and test-retest reproducibility of phase-contrast MRI (PC-MRI)-measured flow and velocity parameters in intracranial arteries. Highest flow (HF), lowest flow (LF), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured at two dates in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral arteries of 30 healthy volunteers using two-dimensional PC-MRI at 3 T. Least detectable difference (LDD) was calculated. In the left ACA, HF was (mean (range, LDD)) 126 ml/min (36-312, 59 %), LF 61 ml/min (0-156, 101 %), PSV 64 cm/s (32-141, 67 %), and EDV 35 cm/s (18-55, 42 %); in the right ACA, HF was 154 ml/min (42-246, 49 %), LF 77 ml/min (0-156, 131 %), PSV 75 cm/s (26-161, 82 %), and EDV 39 cm/s (7-59, 67 %). In the left MCA, HF was 235 ml/min (126-372, 35 %), LF 116 ml/min (42-186, 48 %), PSV 90 cm/s (55-183, 39 %), and EDV 46 cm/s (20-66, 28 %); in the right MCA, HF was 238 ml/min (162-342, 44 %), LF 120 ml/min (72-216, 48 %), PSV 88 cm/s (55-141, 35 %), and EDV 45 cm/s (26-67, 23 %). In the left PCA, HF was 108 ml/min (42-168, 54 %), LF 53 ml/min (18-108, 64 %), PSV 50 cm/s (24-77, 63 %), and EDV 28 cm/s (14-40, 45 %); in the right PCA, HF was 98 ml/min (30-162, 49 %), LF 49 ml/min (12-84, 55 %), PSV 47 cm/s (27-88, 59 %), and EDV 27 cm/s (16-41, 45 %). PC-MRI-measured flow and velocity parameters in the main intracranial arteries have large normal ranges. Reproducibility is highest in MCA. (orig.)

  18. Normal ranges and test-retest reproducibility of flow and velocity parameters in intracranial arteries measured with phase-contrast magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Correia de Verdier, Maria; Wikstroem, Johan [Uppsala University Hospital, Department of Radiology, Uppsala University, Uppsala (Sweden)

    2016-05-15

    The purpose of the present study was to investigate normal ranges and test-retest reproducibility of phase-contrast MRI (PC-MRI)-measured flow and velocity parameters in intracranial arteries. Highest flow (HF), lowest flow (LF), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured at two dates in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral arteries of 30 healthy volunteers using two-dimensional PC-MRI at 3 T. Least detectable difference (LDD) was calculated. In the left ACA, HF was (mean (range, LDD)) 126 ml/min (36-312, 59 %), LF 61 ml/min (0-156, 101 %), PSV 64 cm/s (32-141, 67 %), and EDV 35 cm/s (18-55, 42 %); in the right ACA, HF was 154 ml/min (42-246, 49 %), LF 77 ml/min (0-156, 131 %), PSV 75 cm/s (26-161, 82 %), and EDV 39 cm/s (7-59, 67 %). In the left MCA, HF was 235 ml/min (126-372, 35 %), LF 116 ml/min (42-186, 48 %), PSV 90 cm/s (55-183, 39 %), and EDV 46 cm/s (20-66, 28 %); in the right MCA, HF was 238 ml/min (162-342, 44 %), LF 120 ml/min (72-216, 48 %), PSV 88 cm/s (55-141, 35 %), and EDV 45 cm/s (26-67, 23 %). In the left PCA, HF was 108 ml/min (42-168, 54 %), LF 53 ml/min (18-108, 64 %), PSV 50 cm/s (24-77, 63 %), and EDV 28 cm/s (14-40, 45 %); in the right PCA, HF was 98 ml/min (30-162, 49 %), LF 49 ml/min (12-84, 55 %), PSV 47 cm/s (27-88, 59 %), and EDV 27 cm/s (16-41, 45 %). PC-MRI-measured flow and velocity parameters in the main intracranial arteries have large normal ranges. Reproducibility is highest in MCA. (orig.)

  19. Intrinsic magnetic torque at low magnetic induction

    International Nuclear Information System (INIS)

    Doria, M.M.; Oliveira, I.G. de.

    1993-01-01

    Using anisotropic London theory the intrinsic magnetic torque for extreme type II uniaxial superconductors for any value of the magnetic induction is obtained. It is considered the vortex lines straight and take into account the contribution of the supercurrents flowing inside the vortex core within the London theory. It is shown that the interline and intra line free energies give opposite torque contributions, the first drives the magnetic induction parallel to the superconductor's axis of symmetry and the second orthogonal to it. At high magnetic induction torque expression obtained generalizes V. Kogan's formula since it has no free parameters other than the anisotropy γ = m 1 /m 3 and the Ginzburg-Landau parameter κ. At low magnetic induction it is proposed a way to observe vortex chains effects in the total torque based on the fact that London theory is linear and the energy to make a single vortex line in space is independent of the magnetic induction. (author)

  20. Supplementation of Antipsychotic Treatment with the Amino Acid Sarcosine Influences Proton Magnetic Resonance Spectroscopy Parameters in Left Frontal White Matter in Patients with Schizophrenia

    Directory of Open Access Journals (Sweden)

    Dominik Strzelecki

    2015-10-01

    Full Text Available Dysfunction of the glutamatergic system, the main stimulating system in the brain, has a major role in pathogenesis of schizophrenia. The frontal white matter (WM is partially composed of axons from glutamatergic pyramidal neurons and glia with glutamatergic receptors. The natural amino acid sarcosine, a component of a normal diet, inhibits the glycine type 1 transporter, increasing the glycine level. Thus, it modulates glutamatergic transmission through the glutamatergic ionotropic NMDA (N-methyl-d-aspartate receptor, which requires glycine as a co-agonist. To evaluate the concentrations of brain metabolites (NAA, N-acetylaspartate; Glx, complex of glutamate, glutamine, and γ-aminobutyric acid (GABA; mI, myo-inositol; Cr, creatine; Cho, choline in the left frontal WM, Proton Nuclear Magnetic Resonance (1H-NMR spectroscopy was used. Twenty-five patients randomly chosen from a group of fifty with stable schizophrenia (DSM-IV-TR and dominant negative symptoms, who were receiving antipsychotic therapy, were administered 2 g of sarcosine daily for six months. The remaining 25 patients received placebo. Assignment was double blinded. 1H-NMR spectroscopy (1.5 T was performed twice: before and after the intervention. NAA, Glx and mI were evaluated as Cr and Cho ratios. All patients were also assessed twice with the Positive and Negative Syndrome Scale (PANSS. Results were compared between groups and in two time points in each group. The sarcosine group demonstrated a significant decrease in WM Glx/Cr and Glx/Cho ratios compared to controls after six months of therapy. In the experimental group, the final NAA/Cr ratio significantly increased and Glx/Cr ratio significantly decreased compared to baseline values. Improvement in the PANSS scores was significant only in the sarcosine group. In patients with schizophrenia, sarcosine augmentation can reverse the negative effect of glutamatergic system overstimulation, with a simultaneous beneficial increase

  1. Evaporation and vapor shielding of CFC targets exposed to plasma heat fluxes relevant to ITER ELMs

    International Nuclear Information System (INIS)

    Safronov, V.M.; Arkhipov, N.I.; Landman, I.S.; Pestchanyi, S.E.; Toporkov, D.A.; Zhitlukhin, A.M.

    2009-01-01

    Carbon fibre composite NB31 was tested at plasma gun facility MK-200UG by plasma heat fluxes relevant to Edge Localised Modes in ITER. The paper reports the results obtained on the evaporation threshold of carbon fibre composite, the velocity of carbon vapor motion along and across the magnetic field lines, and the parameters of carbon plasma such as temperature, density and ionization state. First experimental results on investigation of the vapor shield onset conditions are presented also. The obtained experimental data are compared with the results of numerical modeling.

  2. Reconnection Scaling Experiment (RSX): Magnetic Reconnection in Linear Geometry

    Science.gov (United States)

    Intrator, T.; Sovinec, C.; Begay, D.; Wurden, G.; Furno, I.; Werley, C.; Fisher, M.; Vermare, L.; Fienup, W.

    2001-10-01

    The linear Reconnection Scaling Experiment (RSX) at LANL is a new experiment that can create MHD relevant plasmas to look at the physics of magnetic reconnection. This experiment can scale many relevant parameters because the guns that generate the plasma and current channels do not depend on equilibrium or force balance for startup. We describe the experiment and initial electrostatic and magnetic probe data. Two parallel current channels sweep down a long plasma column and probe data accumulated over many shots gives 3D movies of magnetic reconnection. Our first data tries to define an operating regime free from kink instabilities that might otherwise confuse the data and shot repeatability. We compare this with MHD 2 fluid NIMROD simulations of the single current channel kink stability boundary for a variety of experimental conditions.

  3. Report on the production magnet measurement system for the Fermilab Energy-Saver superconducting dipoles and quadrupoles

    International Nuclear Information System (INIS)

    Brown, B.C.; Cooper, W.E.; Garvey, J.D.

    1983-03-01

    The measurement system and procedures used to test more than 900 superconducting dipole magnets and more than 275 superconducting quadrupole magnets for the Fermilab Energy Saver are described. The system is designed to measure nearly all parameters relevant to the use of the magnets in the accelerator including maximum field capability and precision field measurements. The performance of the instrumentation with regard to precision, reliability, and operational needs for high volume testing will be described. Previous reports have described the measurement system used during development of the Saver magnets from which this system has evolved

  4. Tribology of magnetic storage systems

    Science.gov (United States)

    Bhushan, Bharat

    1992-01-01

    The construction and the materials used in different magnetic storage devices are defined. The theories of friction and adhesion, interface temperatures, wear, and solid-liquid lubrication relevant to magnetic storage systems are presented. Experimental data are presented wherever possible to support the relevant theories advanced.

  5. Clinical Relevance of Adipokines

    Directory of Open Access Journals (Sweden)

    Matthias Blüher

    2012-10-01

    Full Text Available The incidence of obesity has increased dramatically during recent decades. Obesity increases the risk for metabolic and cardiovascular diseases and may therefore contribute to premature death. With increasing fat mass, secretion of adipose tissue derived bioactive molecules (adipokines changes towards a pro-inflammatory, diabetogenic and atherogenic pattern. Adipokines are involved in the regulation of appetite and satiety, energy expenditure, activity, endothelial function, hemostasis, blood pressure, insulin sensitivity, energy metabolism in insulin sensitive tissues, adipogenesis, fat distribution and insulin secretion in pancreatic β-cells. Therefore, adipokines are clinically relevant as biomarkers for fat distribution, adipose tissue function, liver fat content, insulin sensitivity, chronic inflammation and have the potential for future pharmacological treatment strategies for obesity and its related diseases. This review focuses on the clinical relevance of selected adipokines as markers or predictors of obesity related diseases and as potential therapeutic tools or targets in metabolic and cardiovascular diseases.

  6. Fluid model of the magnetic presheath in a turbulent plasma

    International Nuclear Information System (INIS)

    Stanojevic, M; Duhovnik, J; Jelic, N; Kendl, A; Kuhn, S

    2005-01-01

    A fluid model of the magnetic presheath in a turbulent boundary plasma is presented. Turbulent transport corrections of the classical three-dimensional fluid transport equations, which can be used to study magnetic presheaths in various geometries, are derived by means of the ensemble averaging procedure from the statistical theory of plasma turbulence. Then, the magnetic presheath in front of an infinite plane surface is analysed in detail. The linearized planar magnetic presheath equations are applied to the plasma-presheath-magnetic-presheath boundary (i.e. the magnetic presheath edge), whereas the original non-linear planar magnetic presheath equations are used for the entire magnetic presheath, allowing for various sets of experimentally relevant free model parameters to be applied. Important new results of this study are, among others, new expressions for the fluid Bohm criterion at the Debye sheath edge and for the ion flux density perpendicular to the wall. These new results, which exhibit corrections due to the turbulent charged particle transport, can qualitatively explain the fact that whenever the angle between the magnetic field and the wall is very small (i.e. several degrees) or zero, electric currents, measured by Langmuir probes in the boundary regions of nuclear fusion devices and in various low-temperature plasmas, are anomalously enhanced in comparison with those expected or predicted by other theoretical models

  7. Information Needs/Relevance

    OpenAIRE

    Wildemuth, Barbara M.

    2009-01-01

    A user's interaction with a DL is often initiated as the result of the user experiencing an information need of some kind. Aspects of that experience and how it might affect the user's interactions with the DL are discussed in this module. In addition, users continuously make decisions about and evaluations of the materials retrieved from a DL, relative to their information needs. Relevance judgments, and their relationship to the user's information needs, are discussed in this module. Draft

  8. Modifications in dynamic contrast-enhanced magnetic resonance imaging parameters after α-particle-emitting ²²⁷Th-trastuzumab therapy of HER2-expressing ovarian cancer xenografts.

    Science.gov (United States)

    Heyerdahl, Helen; Røe, Kathrine; Brevik, Ellen Mengshoel; Dahle, Jostein

    2013-09-01

    The purpose of this study was to investigate the effect of α-particle-emitting (227)Th-trastuzumab radioimmunotherapy on tumor vasculature to increase the knowledge about the mechanisms of action of (227)Th-trastuzumab. Human HER2-expressing SKOV-3 ovarian cancer xenografts were grown bilaterally in athymic nude mice. Mice with tumor volumes 253 ± 36 mm(3) (mean ± SEM) were treated with a single injection of either (227)Th-trastuzumab at a dose of 1000 kBq/kg body weight (treated group, n=14 tumors) or 0.9% NaCl (control group, n=10 tumors). Dynamic T1-weighted contrast-enhanced magnetic resonance imaging (DCEMRI) was used to study the effect of (227)Th-trastuzumab on tumor vasculature. DCEMRI was performed before treatment and 1, 2, and 3 weeks after therapy. Tumor contrast-enhancement curves were extracted voxel by voxel and fitted to the Brix pharmacokinetic model. Pharmacokinetic parameters for the tumors that underwent radioimmunotherapy were compared with the corresponding parameters of control tumors. Significant increases of kep, the rate constant of diffusion from the extravascular extracellular space to the plasma (PTh-trastuzumab treatment of HER2-expressing ovarian cancer xenografts. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. New color-magnetic defects in dense quark matter

    Science.gov (United States)

    Haber, Alexander; Schmitt, Andreas

    2018-06-01

    Color-flavor locked (CFL) quark matter expels color-magnetic fields due to the Meissner effect. One of these fields carries an admixture of the ordinary abelian magnetic field and therefore flux tubes may form if CFL matter is exposed to a magnetic field, possibly in the interior of neutron stars or in quark stars. We employ a Ginzburg–Landau approach for three massless quark flavors, which takes into account the multi-component nature of color superconductivity. Based on the weak-coupling expressions for the Ginzburg–Landau parameters, we identify the regime where CFL is a type-II color superconductor and compute the radial profiles of different color-magnetic flux tubes. Among the configurations without baryon circulation we find a new solution that is energetically preferred over the flux tubes previously discussed in the literature in the parameter regime relevant for compact stars. Within the same setup, we also find a new defect in the 2SC phase, namely magnetic domain walls, which emerge naturally from the previously studied flux tubes if a more general ansatz for the order parameter is used. Color-magnetic defects in the interior of compact stars allow for sustained deformations of the star, potentially strong enough to produce detectable gravitational waves.

  10. Parametric analysis of a magnetized cylindrical plasma

    International Nuclear Information System (INIS)

    Ahedo, Eduardo

    2009-01-01

    The relevant macroscopic model, the spatial structure, and the parametric regimes of a low-pressure plasma confined by a cylinder and an axial magnetic field is discussed for the small-Debye length limit, making use of asymptotic techniques. The plasma response is fully characterized by three-dimensionless parameters, related to the electron gyroradius, and the electron and ion collision mean-free-paths. There are the unmagnetized regime, the main magnetized regime, and, for a low electron-collisionality plasma, an intermediate-magnetization regime. In the magnetized regimes, electron azimuthal inertia is shown to be a dominant phenomenon in part of the quasineutral plasma region and to set up before ion radial inertia. In the main magnetized regime, the plasma structure consists of a bulk diffusive region, a thin layer governed by electron inertia, a thinner sublayer controlled by ion inertia, and the non-neutral Debye sheath. The solution of the main inertial layer yields that the electron azimuthal energy near the wall is larger than the electron thermal energy, making electron resistivity effects non-negligible. The electron Boltzmann relation is satisfied only in the very vicinity of the Debye sheath edge. Ion collisionality effects are irrelevant in the magnetized regime. Simple scaling laws for plasma production and particle and energy fluxes to the wall are derived.

  11. Computer simulations of equilibrium magnetization and microstructure in magnetic fluids

    Science.gov (United States)

    Rosa, A. P.; Abade, G. C.; Cunha, F. R.

    2017-09-01

    In this work, Monte Carlo and Brownian Dynamics simulations are developed to compute the equilibrium magnetization of a magnetic fluid under action of a homogeneous applied magnetic field. The particles are free of inertia and modeled as hard spheres with the same diameters. Two different periodic boundary conditions are implemented: the minimum image method and Ewald summation technique by replicating a finite number of particles throughout the suspension volume. A comparison of the equilibrium magnetization resulting from the minimum image approach and Ewald sums is performed by using Monte Carlo simulations. The Monte Carlo simulations with minimum image and lattice sums are used to investigate suspension microstructure by computing the important radial pair-distribution function go(r), which measures the probability density of finding a second particle at a distance r from a reference particle. This function provides relevant information on structure formation and its anisotropy through the suspension. The numerical results of go(r) are compared with theoretical predictions based on quite a different approach in the absence of the field and dipole-dipole interactions. A very good quantitative agreement is found for a particle volume fraction of 0.15, providing a validation of the present simulations. In general, the investigated suspensions are dominated by structures like dimmer and trimmer chains with trimmers having probability to form an order of magnitude lower than dimmers. Using Monte Carlo with lattice sums, the density distribution function g2(r) is also examined. Whenever this function is different from zero, it indicates structure-anisotropy in the suspension. The dependence of the equilibrium magnetization on the applied field, the magnetic particle volume fraction, and the magnitude of the dipole-dipole magnetic interactions for both boundary conditions are explored in this work. Results show that at dilute regimes and with moderate dipole

  12. Histogram analysis parameters of dynamic contrast-enhanced magnetic resonance imaging can predict histopathological findings including proliferation potential, cellularity, and nucleic areas in head and neck squamous cell carcinoma.

    Science.gov (United States)

    Surov, Alexey; Meyer, Hans Jonas; Leifels, Leonard; Höhn, Anne-Kathrin; Richter, Cindy; Winter, Karsten

    2018-04-20

    Our purpose was to analyze possible associations between histogram analysis parameters of dynamic contrast-enhanced magnetic resonance imaging DCE MRI and histopathological findings like proliferation index, cell count and nucleic areas in head and neck squamous cell carcinoma (HNSCC). 30 patients (mean age 57.0 years) with primary HNSCC were included in the study. In every case, histogram analysis parameters of K trans , V e , and K ep were estimated using a mathlab based software. Tumor proliferation index, cell count, and nucleic areas were estimated on Ki 67 antigen stained specimens. Spearman's non-parametric rank sum correlation coefficients were calculated between DCE and different histopathological parameters. KI 67 correlated with K trans min ( p = -0.386, P = 0.043) and s K trans skewness ( p = 0.382, P = 0.045), V e min ( p = -0.473, P = 0.011), Ve entropy ( p = 0.424, P = 0.025), and K ep entropy ( p = 0.464, P = 0.013). Cell count correlated with K trans kurtosis ( p = 0.40, P = 0.034), V e entropy ( p = 0.475, P = 0.011). Total nucleic area correlated with V e max ( p = 0.386, P = 0.042) and V e entropy ( p = 0.411, P = 0.030). In G1/2 tumors, only K trans entropy correlated well with total ( P =0.78, P =0.013) and average nucleic areas ( p = 0.655, P = 0.006). In G3 tumors, KI 67 correlated with Ve min ( p = -0.552, P = 0.022) and V e entropy ( p = 0.524, P = 0.031). Ve max correlated with total nucleic area ( p = 0.483, P = 0.049). Kep max correlated with total area ( p = -0.51, P = 0.037), and K ep entropy with KI 67 ( p = 0.567, P = 0.018). We concluded that histogram-based parameters skewness, kurtosis and entropy of K trans , V e , and K ep can be used as markers for proliferation activity, cellularity and nucleic content in HNSCC. Tumor grading influences significantly associations between perfusion and histopathological parameters.

  13. Contrasting the magnetic response between magnetic-glass and reentrant spin-glass

    OpenAIRE

    Roy, S. B.; Chattopadhyay, M. K.

    2008-01-01

    Magnetic-glass is a recently identified phenomenon in various classes of magnetic systems undergoing a first order magnetic phase transition. We shall highlight here a few experimentally determined characteristics of magnetic-glass and the relevant set of experiments, which will enable to distinguish a magnetic-glass unequivocally from the well known phenomena of spin-glass and reentrant spin-glass.

  14. Conventional magnets. Pt. 2

    International Nuclear Information System (INIS)

    Marks, N.

    1994-01-01

    This second paper covers the wide range of techniques associated with a.c. and pulsed magnets and associated power supplies. The necessary changes in magnet design to minimise eddy losses in low frequency magnets are first considered and this leads to a broader discussion of the different types of steel used in magnet yokes. Inductance is then considered and the traditional power supply circuit used for a.c. magnets is described. The paper then presents a simple description of the higher-frequency pulsed magnets and supply circuits used for injection and extraction and contrasts a number of different design concepts for both kicker and septum systems. In conclusion, the relevant properties of high-frequency magnetic materials are briefly reviewed. (orig.)

  15. [Relevant public health enteropathogens].

    Science.gov (United States)

    Riveros, Maribel; Ochoa, Theresa J

    2015-01-01

    Diarrhea remains the third leading cause of death in children under five years, despite recent advances in the management and prevention of this disease. It is caused by multiple pathogens, however, the prevalence of each varies by age group, geographical area and the scenario where cases (community vs hospital) are recorded. The most relevant pathogens in public health are those associated with the highest burden of disease, severity, complications and mortality. In our country, norovirus, Campylobacter and diarrheagenic E. coli are the most prevalent pathogens at the community level in children. In this paper we review the local epidemiology and potential areas of development in five selected pathogens: rotavirus, norovirus, Shiga toxin-producing E. coli (STEC), Shigella and Salmonella. Of these, rotavirus is the most important in the pediatric population and the main agent responsible for child mortality from diarrhea. The introduction of rotavirus vaccination in Peru will have a significant impact on disease burden and mortality from diarrhea. However, surveillance studies are needed to determine the impact of vaccination and changes in the epidemiology of diarrhea in Peru following the introduction of new vaccines, as well as antibiotic resistance surveillance of clinical relevant bacteria.

  16. First-wall design limitations for linear magnetic fusion (LMF) reactors

    International Nuclear Information System (INIS)

    Gryczkowski, G.E.; Krakowski, R.A.; Steinhauer, L.C.; Zumdieck, J.

    1978-01-01

    One approach to the endloss problem in linear magnetic fusion (LMF) uses high magnetic field to reduce the required confinement time. This approach is limited by magnet stresses and bremsstrahlung heating of the first wall; the first-wall thermal-pulsing issue is addressed. Pertinent thermophysical parameters are developed in the context of high-field LMF to identify promising first-wall materials, and thermal fatigue experiments relevant to LMF first walls are reviewed. High-flux first-wall concepts are described which include both solid and evaporating first-wall configurations

  17. Impact of stochastic primordial magnetic fields on the scalar contribution to cosmic microwave background anisotropies

    International Nuclear Information System (INIS)

    Finelli, Fabio; Paci, Francesco; Paoletti, Daniela

    2008-01-01

    We study the impact of a stochastic background of primordial magnetic fields on the scalar contribution of cosmic microwave background (CMB) anisotropies and on the matter power spectrum. We give the correct initial conditions for cosmological perturbations and the exact expressions for the energy density and Lorentz force associated to the stochastic background of primordial magnetic fields, given a power-law for their spectra cut at a damping scale. The dependence of the CMB temperature and polarization spectra on the relevant parameters of the primordial magnetic fields is illustrated.

  18. Parameter analysis and optimal design for low-speed permanent magnet wind turbine generators%低速永磁风力发电机的参数分析及优化设计

    Institute of Scientific and Technical Information of China (English)

    何庆领; 王群京

    2011-01-01

    文章讨论了低速永磁同步风力发电机的设计特点,为了有效地减少阻力矩,采用分数槽绕组,为减少漏磁通,采用瓦片型和放射状的永磁体安装结构,并重点对结构参数与运行性能之间的内在关系进行了参数分析,为风力发电机本体的优化设计打下基础.在一定安装尺寸的限制下,以电机效率作为优化目标,采用基于混沌理论的最优化算法获取风力发电机的最大输出效率.%This paper discusses the design characteristics of low-speed permanent magnet synchronous wind turbine generator, including the use of fractional slot windings to effectively reduce the resistance moment, the use of tiles and reflective-like structure to reduce leakage flux,and the installation of permanent magnet The intrinsic relationship between structural parameters and operational performance is also analyzed for the optimal design of wind turbine foundation. Aiming at optimizing the motor efficiency, the optimization algorithm based on chaos theory can be used to obtain the maximum output efficiency of wind turbine generator under a certain restriction of installation size.

  19. A new multi-line cusp magnetic field plasma device (MPD) with variable magnetic field

    Science.gov (United States)

    Patel, A. D.; Sharma, M.; Ramasubramanian, N.; Ganesh, R.; Chattopadhyay, P. K.

    2018-04-01

    A new multi-line cusp magnetic field plasma device consisting of electromagnets with core material has been constructed with a capability to experimentally control the relative volume fractions of magnetized to unmagnetized plasma volume as well as accurate control on the gradient length scales of mean density and temperature profiles. Argon plasma has been produced using a hot tungsten cathode over a wide range of pressures 5 × 10-5 -1 × 10-3 mbar, achieving plasma densities ranging from 109 to 1011 cm-3 and the electron temperature in the range 1-8 eV. The radial profiles of plasma parameters measured along the non-cusp region (in between two consecutive magnets) show a finite region with uniform and quiescent plasma, where the magnetic field is very low such that the ions are unmagnetized. Beyond that region, both plasma species are magnetized and the profiles show gradients both in temperature and density. The electrostatic fluctuation measured using a Langmuir probe radially along the non-cusp region shows less than 1% (δIisat/Iisat physics parameter space relevant to both laboratory multi-scale plasmas and astrophysical plasmas.

  20. Other relevant biological papers

    International Nuclear Information System (INIS)

    Shimizu, M.

    1989-01-01

    A considerable number of CRESP-relevant papers concerning deep-sea biology and radioecology have been published. It is the purpose of this study to call attention to them. They fall into three general categories. The first is papers of general interest. They are mentioned only briefly, and include text references to the global bibliography at the end of the volume. The second are papers that are not only mentioned and referenced, but for various reasons are described in abstract form. The last is a list of papers compiled by H.S.J. Roe specifically for this volume. They are listed in bibliographic form, and are also included in the global bibliography at the end of the volume

  1. Alternative lines with magnetic plasma confinement

    International Nuclear Information System (INIS)

    Wobig, H.

    1981-01-01

    Plasma confinement with the aid of a magnetic field is the most common and also the most frequently investigated principle on the way to controlled nuclear fusion. Apart from the Tokamak principle, which is the most advanced principle as far as fusion-relevant plasma parameters are concerned, also other approaches are being investigated, e.g. the mirror device, the bumpy tons, and the stellarator. In principle, all three concepts permit 'stationary' plasma confinement in a stationary fusion reactor. Compared with the pulsed Tokamak reactor, this is a considerable advantage. (orig./GG) [de

  2. Review and comparison of magnet designs for magnetic refrigeration

    DEFF Research Database (Denmark)

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

    2010-01-01

    One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving...... the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated...... and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, Λcool. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis...

  3. Investigations on the magnetization behavior of magnetic composite particles

    Energy Technology Data Exchange (ETDEWEB)

    Eichholz, Christian [Process Research and Chemical Engineering, BASF SE, Ludwigshafen (Germany); Knoll, Johannes, E-mail: johannes.knoll@kit.edu [Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Lerche, Dietmar [L.U.M. GmbH, Berlin (Germany); Nirschl, Hermann [Institute of Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2014-11-15

    In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments. - Highlights: • New model for magnetizability calculation of magnetic composite particles. • New method for particle bulk characterization relating to their magnetizability. • Model verification due to experimental data.

  4. Investigations on the magnetization behavior of magnetic composite particles

    International Nuclear Information System (INIS)

    Eichholz, Christian; Knoll, Johannes; Lerche, Dietmar; Nirschl, Hermann

    2014-01-01

    In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments. - Highlights: • New model for magnetizability calculation of magnetic composite particles. • New method for particle bulk characterization relating to their magnetizability. • Model verification due to experimental data

  5. Physical parameters for the application of MRI. Restrictions due to physiological consequences and guidelines

    International Nuclear Information System (INIS)

    Frese, G.; Hebrank, F.X.; Renz, W.; Storch, T.

    1998-01-01

    Purpose: The standards and regulations concerning the protection of patients and operator staff within the context of MRI are compiled. Resulting consequences regarding physical parameters are evaluated. Material and methods: The static magnetic field, heating effects caused by RF-fields and acoustical noise are outlined. The actual boundaries of these parameters are compared against the relevant published standards. Peripheral stimulation limits due to pulsed gradient fields have been determined in a new clinical study. Results: Many parameters recommended for the normal operating mode are already exceeded during routine MRI. Referring to our clinical study, we found that limits recommended in the MRI relevant standards are unnecessarily conservative and can actually be doubled. (orig./AJ) [de

  6. Detailed crystallization study of co-precipitated Y{sub 1.47} Gd{sub 1.53} Fe{sub 5} O{sub 12} and relevant magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Serra, Rogerio Arving [Instituto de Criminalistica Carlos Eboli (ICCE), Rio de Janeiro, RJ (Brazil); Ogasawara, Tsuneharu; Ogasawara, Angelica Soares [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Dept. de Engenharia Metalurgica e de Materiais]. E-mail: ogasawat@metalmat.ufrj.br

    2007-07-01

    The crystallization process of co-precipitated Y{sub 1.5}Gd{sub 1.5}Fe{sub 5}O{sub 12} powder heated up to 1000 deg C at rate of 5 deg C min{sup -1} was investigated. Above 810 deg C crystalline Y{sub 1.47}Gd{sub 1.53}Fe{sub 5}O{sub 12} was obtained with a lattice parameter of 12.41 A and a theoretical density of 5.84 g cm{sup -3}. Dry pressed rings were sintered at 1270 and 1320 deg C, increasing the grain-size from 3.1 to 6.5 {mu}m, the theoretical density by 87.6 to 95.3% and decreasing H{sub c} from 2.9725 to 1.4005 Oe. Additionally, Hc increased when the frequency of the hysteresis graph varied from 60 Hz to 10 kHz, the curie temperature was 282.4 deg C and Ms equalled 9.25 emu g{sup -1} (0.17 kG) agreeing well with the B{sub s}-value of the hysteresis graph and literature values. (author)

  7. User perspectives on relevance criteria

    DEFF Research Database (Denmark)

    Maglaughlin, Kelly L.; Sonnenwald, Diane H.

    2002-01-01

    , partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance......This study investigates the use of criteria to assess relevant, partially relevant, and not-relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant...... matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially...

  8. Quantitative interpretation of the magnetic susceptibility frequency dependence

    Science.gov (United States)

    Ustra, Andrea; Mendonça, Carlos A.; Leite, Aruã; Jovane, Luigi; Trindade, Ricardo I. F.

    2018-05-01

    Low-field mass-specific magnetic susceptibility (MS) measurements using multifrequency alternating fields are commonly used to evaluate concentration of ferrimagnetic particles in the transition of superparamagnetic (SP) to stable single domain (SSD). In classical palaeomagnetic analyses, this measurement serves as a preliminary assessment of rock samples providing rapid, non-destructive, economical and easy information of magnetic properties. The SP-SSD transition is relevant in environmental studies because it has been associated with several geological and biogeochemical processes affecting magnetic mineralogy. MS is a complex function of mineral-type and grain-size distribution, as well as measuring parameters such as external field magnitude and frequency. In this work, we propose a new technique to obtain quantitative information on grain-size variations of magnetic particles in the SP-SSD transition by inverting frequency-dependent susceptibility. We introduce a descriptive parameter named as `limiting frequency effect' that provides an accurate estimation of MS loss with frequency. Numerical simulations show the methodology capability in providing data fitting and model parameters in many practical situations. Real-data applications with magnetite nanoparticles and core samples from sediments of Poggio le Guaine section of Umbria-Marche Basin (Italy) provide additional information not clearly recognized when interpreting cruder MS data. Caution is needed when interpreting frequency dependence in terms of single relaxation processes, which are not universally applicable and depend upon the nature of magnetic mineral in the material. Nevertheless, the proposed technique is a promising tool for SP-SSD content analyses.

  9. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2010-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focussed. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations.The set of numerical coefficients defining this linear combination is then what one refers.......The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  10. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2014-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focused. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations. The set of numerical coefficients defining this linear combination is then what one refers....... The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  11. Bomb parameters

    International Nuclear Information System (INIS)

    Kerr, George D.; Young, Rebert W.; Cullings, Harry M.; Christry, Robert F.

    2005-01-01

    The reconstruction of neutron and gamma-ray doses at Hiroshima and Nagasaki begins with a determination of the parameters describing the explosion. The calculations of the air transported radiation fields and survivor doses from the Hiroshima and Nagasaki bombs require knowledge of a variety of parameters related to the explosions. These various parameters include the heading of the bomber when the bomb was released, the epicenters of the explosions, the bomb yields, and the tilt of the bombs at time of explosion. The epicenter of a bomb is the explosion point in air that is specified in terms of a burst height and a hypocenter (or the point on the ground directly below the epicenter of the explosion). The current reassessment refines the energy yield and burst height for the Hiroshima bomb, as well as the locations of the Hiroshima and Nagasaki hypocenters on the modern city maps used in the analysis of the activation data for neutrons and TLD data for gamma rays. (J.P.N.)

  12. Non-destructive testing: magnetizing equipment for magnetic particle inspection

    International Nuclear Information System (INIS)

    1975-07-01

    Magnetizing equipment for magnetic particle inspection serves to produce a magnetic field of suitable size and direction in a workpiece under examination. The characteristic parameters of this equipment are given in this standard along with their method of determination if this is necessary. (orig./AK) [de

  13. Use of magnetic compression based on amorphous alloys as a drive for induction linacs

    International Nuclear Information System (INIS)

    Birx, D.L.; Cook, E.G.; Hawkins, S.A.; Poor, S.E.; Reginato, L.; Schmidt, J.; Smith, M.W.

    1984-01-01

    In anticipation of current and future needs for the Particle Beam Program and other programs at the Lawrence Livermore National Laboratory, we are continuing efforts in the development of high-repetition-rate magnetic pulse compressors that use ferromagnetic metallic glasses, both in the linear and very high saturation rates. These devices are ideally suited as drivers for linear induction accelerators, where duty factor or average repetition rates (hundred of hertz) requirements exceed the parameters that can be achieved by pulse compression using spark gaps. The technique of magnetic pulse compression has been with use for several decades, but relatively recent developments in rapidly quenched magnetic metals of very thin cross sections, has led to the development of state-of-the-art magnetic pulse compressors with very high peak power, repetition rates, and reliability. This paper will describe results of recent experiments and the relevant electrical and mechanical properties of magnetic pulse compressors to achieve high efficiency and reliability

  14. Magnetic x-ray microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Paul G [Computer-Aided Engineering Center, University of Wisconsin, Madison, WI 53706 (United States); Isaacs, Eric D [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2006-08-07

    Magnetic x-ray microdiffraction uses the structural specificity of x-ray diffraction to probe complex magnetic structures at the length scales relevant to physical phenomena including domain dynamics and phase transitions. Conventional magnetic crystallography techniques such as neutron or x-ray diffraction lack this spatial resolution. The combination of both reciprocal space and real space resolution with a rich magnetic cross section allows new microscopy techniques to be developed and applied to magnetism at the scale of single domains. Potential applications include a wide range of magnetic problems in nanomagnetism, the interaction of strain, polarization and magnetization in complex oxides and spatially resolved studies of magnetic phase transitions. We present the physical basis for x-ray microdiffraction and magnetic scattering processes, review microdiffraction domain imaging techniques in antiferromagnetic and ferromagnetic materials and discuss potential directions for studies. (topical review)

  15. Magnets and magnetic materials

    International Nuclear Information System (INIS)

    Meuris, Ch.; Rifflet, J.M.

    2007-01-01

    The Large Hadron Collider (LHC), the world's largest highest-energy particle collider that the CERN plans to commission in 2008, gets a double boost from superconducting magnet technology. Superconducting magnets are first used to guide the particles scheduled for collision through the accelerator, and then to observe the events triggered by the collision inside giant detectors in a known magnetic field. Despite the installation's massive dimensions, all this is done with minimal expenditure of energy. (author)

  16. Magnetic La.sub.1-x./sub.Sr.sub.x./sub.MnO.sub.3./sub. nanoparticles as contrast agents for MRI: the parameters affecting 1H transverse relaxation

    Czech Academy of Sciences Publication Activity Database

    Veverka, Pavel; Kaman, Ondřej; Kačenka, Michal; Herynek, V.; Veverka, Miroslav; Šantavá, Eva; Lukeš, I.; Jirák, Zdeněk

    2015-01-01

    Roč. 17, č. 1 (2015), s. 1-11 ISSN 1388-0764 R&D Projects: GA MPO FR-TI3/521; GA ČR(CZ) GAP108/11/0807 Institutional support: RVO:68378271 Keywords : manganese perovskites * manganite * magnetic nanoparticles * magnetic resonance imaging * relaxivity * core –shell particles Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.101, year: 2015

  17. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  18. Electromechanical magnetization switching

    International Nuclear Information System (INIS)

    Chudnovsky, Eugene M.; Jaafar, Reem

    2015-01-01

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

  19. Active Magnetic Bearings – Magnetic Forces

    DEFF Research Database (Denmark)

    Kjølhede, Klaus

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision characterization...... of the magnetic forces are led by using different experimental tests: (I) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor; (II) by measuring the input current and bearing...

  20. Magnetic-seeding filtration

    International Nuclear Information System (INIS)

    Ying, T.Y.; Chin, C.J.; Lu, S.C.; Yiacoumi, S.

    1997-10-01

    Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab

  1. Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors

    Directory of Open Access Journals (Sweden)

    Marek Przybylski

    2016-04-01

    Full Text Available Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated.

  2. The 2017 Magnetism Roadmap

    Science.gov (United States)

    Sander, D.; Valenzuela, S. O.; Makarov, D.; Marrows, C. H.; Fullerton, E. E.; Fischer, P.; McCord, J.; Vavassori, P.; Mangin, S.; Pirro, P.; Hillebrands, B.; Kent, A. D.; Jungwirth, T.; Gutfleisch, O.; Kim, C. G.; Berger, A.

    2017-09-01

    Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an

  3. The 2017 Magnetism Roadmap

    International Nuclear Information System (INIS)

    Sander, D; Valenzuela, S O; Makarov, D

    2017-01-01

    Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an

  4. Crossover phenomena in the critical range near magnetic ordering transition

    Science.gov (United States)

    Köbler, U.

    2018-05-01

    Among the most important issues of Renormalization Group (RG) theory are crossover events and relevant (or non-relevant) interactions. These terms are unknown to atomistic theories but they will be decisive for future field theories of magnetism. In this experimental study the importance of these terms for the critical dynamics above and below magnetic ordering transition is demonstrated on account of new analyses of published data. When crossover events are overlooked and critical data are fitted by a single power function of temperature over a temperature range including a crossover event, imprecise critical exponents result. The rather unsystematic and floating critical exponents reported in literature seem largely to be due to this problem. It is shown that for appropriate data analyses critical exponents are obtained that are to a good approximation rational numbers. In fact, rational critical exponents can be expected when spin dynamics is controlled by the bosons of the continuous magnetic medium (Goldstone bosons). The bosons are essentially magnetic dipole radiation generated by the precessing spins. As a result of the here performed data analyses, critical exponents for the magnetic order parameter of β = 1/2, 1/3, 1/4 and 1/6 are obtained. For the critical paramagnetic susceptibility the exponents are γ = 1 and γ = 4/3.

  5. Neutron scattering studies on frustrated magnets

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2013-01-01

    A lot of frustrated magnetic systems exhibit a nontrivial magnetic order, such as long-wavelength modulation, noncollinear, or noncoplanar order. The nontrivial order may pave the way for the novel magnetic function of matter. Neutron studies are necessary to determine the magnetic structures in the frustrated magnetic systems. In particular, spin-polarized neutron scattering is a useful technique for the investigation of the novel physical properties relevant to the nontrivial spin arrangement. Here some neutron studies on a multiferroic perovskite manganese oxide system are demonstrated as a typical case. The frustrated magnetic systems may also a playground of novel types of local magnetic excitations, which behave like particles in contrast to the magnetic waves. It is becoming a good challenge to study such particle-type magnetic excitations relevant to the magnetic frustration. (author)

  6. Magnetism and magnetic materials

    International Nuclear Information System (INIS)

    1990-01-01

    It describes the actual status of physics in Brazil concerning the study of magnetism and magnetic materials. It gives an overview of different research groups in Brazil, their needs, as well as the investments needed to improve the area. (A.C.A.S.)

  7. Frontiers in Magnetic Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Magnetic Materials focuses on the current achievements and state-of-the-art advancements in magnetic materials. Several lines of development- High-Tc Superconductivity, Nanotechnology and refined experimental techniques among them – raised knowledge and interest in magnetic materials remarkably. The book comprises 24 chapters on the most relevant topics written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students.