WorldWideScience

Sample records for magneto hydro dynamic

  1. Magneto-Hydro-Dynamic Waves In The Collisionless Space Plasma

    Science.gov (United States)

    Dzhalilov, N. S.; Kuznetsov, V. D.; Staude, J.

    2007-12-01

    The instability of magneto-hydro-dynamic (MHD) waves in an anisotropic, collisionless, rarefied hot plasma is studied. Anisotropy properties of such a plasma are caused by a strong magnetic field, when the thermal gas pressures across and along the field become unequal. Moreover, there appears an anisotropy of the thermal fluxes. The study of the anisotropy features of the plasma are motivated by observed solar coronal data. The 16 moments equations derived from the Boltzmann-Vlasov kinetic equation are used. These equations strongly differ from the usual isotropic MHD case. For linear disturbances the wave equations in homogenous anisotropic plasma are deduced. The general dispersion relation for the incompressible wave modes is derived, solved and analyzed. It is shown that a wide wave spectrum with stable and unstable behavior is possible, in contrast to the usual isotropic MHD case. The dependence of the instability on magnetic field, pressure anisotropy, and heat fluxes is investigated. The general instability condition is obtained. The results can be applied to the theory of solar and stellar coronal heating, to wind models and in other modeling, where the collisionless approximation is valid.

  2. Zonal flow driven by energetic particle during magneto-hydro-dynamic burst in a toroidal plasma

    Science.gov (United States)

    Ohshima, S.; Fujisawa, A.; Shimizu, A.; Nakano, H.; Iguchi, H.; Yoshimura, Y.; Nagaoka, K.; Minami, T.; Isobe, M.; Nishimura, S.; Suzuki, C.; Akiyama, T.; Takahashi, C.; Takeuchi, M.; Ito, T.; Watari, T.; Kumazawa, R.; Itoh, S.-I.; Itoh, K.; Matsuoka, K.; Okamura, S.

    2007-11-01

    The internal structural measurements of electric field and density using twin heavy ion beam probes have been performed to elucidate the nonlinear evolution of the magneto-hydro-dynamic (MHD) bursty phenomenon driven by the interaction with high-energy particles in a toroidal plasma. The results have given the finest observation of the internal structure of plasma quantities, such as electric field, density and magnetic field distortion, which nonlinearly develop during the MHD phenomenon. In particular, the finding of a new kind of oscillating zonal flow driven by interaction between energetic particles and MHD modes should be emphasized for burning state plasmas.

  3. Extended magneto-hydro-dynamic model for neoclassical tearing mode computations

    Science.gov (United States)

    Maget, Patrick; Février, Olivier; Garbet, Xavier; Lütjens, Hinrich; Luciani, Jean-Francois; Marx, Alain

    2016-08-01

    A self-consistent fluid model for describing neoclassical tearing modes in global magneto-hydro-dynamic simulations is presented. It is illustrated by its application to a simple toroidal configuration unstable to the (2, 1) tearing mode. The island saturation is verified to increase with the bootstrap current fraction. New features that are specific to this model are evidenced, like the unsteady saturated state of the island, and its deformation to a droplet shape, when the magnetic Prandtl number is not too high. Synthetic diagnostics demonstrate that diamagnetic and neoclassical effects should have in this case a measurable impact on the signature of magnetic islands.

  4. ON THE SELF-SIMILAR SOLUTIONS OF THE MAGNETO-HYDRO-DYNAMIC EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    He Cheng; Xin Zhouping

    2009-01-01

    In this paper, we show that, for the three dimensional incompressible magneto-hydro-dynamic equations, there exists only trivial backward self-similar solution in LP(R3)for p > 3, under some smallness assumption on either the kinetic energy of the self-similar solution related to the velocity field, or the magnetic field.Second, we construct a class of global unique forward self-similar solutions to the three-dimensional MHD equations with small initial data in some sense, being homogeneous of degree -1 and belonging to some Besov space, or the Lorentz space or pseudo-measure space, as motivated by the work in [5].

  5. Transient magneto-peristaltic flow of couple stress biofluids: a magneto-hydro-dynamical study on digestive transport phenomena.

    Science.gov (United States)

    Tripathi, Dharmendra; Anwar Bég, O

    2013-11-01

    Magnetic fields are increasingly being utilized in endoscopy and gastric transport control. In this regard, the present study investigates the influence of a transverse magnetic field in the transient peristaltic rheological transport. An electrically-conducting couple stress non-Newtonian model is employed to accurately simulate physiological fluids in peristaltic flow through a sinusoidally contracting channel of finite length. This model is designed for computing the intra-bolus oesophageal and intestinal pressures during the movement of food bolus in the digestive system under magneto-hydro-dynamic effects. Long wavelength and low Reynolds number approximations have been employed to reduce the governing equations from nonlinear to linear form, this being a valid approach for creeping flows which characterizes physiological dynamics. Analytical approximate solutions for axial velocity, transverse velocity, pressure gradient, local wall shear stress and volumetric flow rate are obtained for the non-dimensional conservation equations subject to appropriate boundary conditions. The effects of couple stress parameter and transverse magnetic field on the velocity profile, pressure distribution, local wall shear stress and the averaged flow rate are discussed with the aid of computational results. The comparative study of non-integral and integral number of waves propagating along the finite length channel is also presented. Magnetic field and non-Newtonian properties are found to strongly influence peristaltic transport.

  6. Experimental investigations on the magneto-hydro-dynamic interaction around a blunt body in a hypersonic unseeded air flow

    Science.gov (United States)

    Cristofolini, Andrea; Borghi, Carlo A.; Neretti, Gabriele; Schettino, Antonio; Trifoni, Eduardo; Battista, Francesco; Passaro, Andrea; Baccarella, Damiano

    2012-11-01

    This paper deals with the experimental investigation on the MHD (magneto-hydro-dynamic or magneto-fluid-dynamic) interaction around a test body immersed into a hypersonic unseeded air flow. The experiments have been carried out in the CIRA plasma wind tunnel SCIROCCO. Two test conditions have been utilized for the experiments with a total pressure of 2.5 and 2.3 bar respectively, a total specific enthalpy of 16 and 12.1 MJ/kg respectively. The air flow was accelerated in the nozzle up to Mach 10. The magnetic induction field is generated by an electromagnet enclosed in the test body and reaches a 0.8 T maximum value in the interaction region.

  7. Finite difference method for inner-layer equations in the resistive MagnetoHydroDynamic stability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tokuda, Shinji [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Watanabe, Tomoko

    1996-08-01

    The matching problem in resistive MagnetoHydroDynamic stability analysis by the asymptotic matching method has been reformulated as an initial-boundary value problem for the inner-layer equations describing the plasma dynamics in the thin layer around a rational surface. The third boundary conditions at boundaries of a finite interval are imposed on the inner layer equations in the formulation instead of asymptotic conditions at infinities. The finite difference method for this problem has been applied to model equations whose solutions are known in a closed form. It has been shown that the initial value problem and the associated eigenvalue problem for the model equations can be solved by the finite difference method with numerical stability. The formulation presented here enables the asymptotic matching method to be a practical method for the resistive MHD stability analysis. (author)

  8. Plasma parameters and electromagnetic forces induced by the magneto hydro dynamic interaction in a hypersonic argon flow experiment

    Science.gov (United States)

    Cristofolini, Andrea; Neretti, Gabriele; Borghi, Carlo A.

    2012-08-01

    This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of Hα and the Hβ lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.

  9. Plasma flow structures as analytical solution of a magneto-hydro-dynamic model with pressure

    Science.gov (United States)

    Paccagnella, R.

    2012-03-01

    In this work starting from a set of magnetohydrodynamic (MHD) equations that describe the dynamical evolution for the pressure driven resistive/interchange modes in a magnetic confinement system, global solutions for the plasma flow relevant for toroidal pinches like tokamaks and reversed field pinches (RFPs) are derived. Analytical solutions for the flow stream function associated with the dominant modes are presented.

  10. Ultra-Relativistic Magneto-Hydro-Dynamic Jets in the context of Gamma Ray Bursts

    CERN Document Server

    Fendt, C; Fendt, Christian; Ouyed, Rachid

    2004-01-01

    We present a detailed numerical study of the dynamics and evolution of ultrarelativistic magnetohydrodynamic jets in the black hole-disk system under extreme magnetization conditions. We find that Lorentz factors of up to 3000 are achieved and derived a modifiedMichel scaling (Gamma ~ sigma) which allows for a wide variation in the flow Lorentz factor. Pending contamination induced by mass-entrainment, the linear Michel scaling links modulations in the ultrarelativistic wind to variations in mass accretion in the disk for a given magnetization. The jet is asymptotically dominated by the toroidal magnetic field allowing for efficient collimation. We discuss our solutions (jets) in the context of Gamma ray bursts and describe the relevant features such as the high variability in the Lorentz factor and how high collimation angles (~ 0-5 degrees), or cylindrical jets, can be achieved. We isolate a jet instability mechanism we refer to as the "bottle-neck" instability which essentially relies on a high magnetizati...

  11. Melting phenomenon in magneto hydro-dynamics steady flow and heat transfer over a moving surface in the presence of thermal radiation

    Science.gov (United States)

    Reda, G. Abdel-Rahman; M. Khader, M.; Ahmed, M. Megahed

    2013-03-01

    The Lie group method is applied to present an analysis of the magneto hydro-dynamics (MHD) steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of thermal radiation. By using the Lie group method, we have presented the transformation groups for the problem apart from the scaling group. The application of this method reduces the partial differential equations (PDEs) with their boundary conditions governing the flow and heat transfer to a system of nonlinear ordinary differential equations (ODEs) with appropriate boundary conditions. The resulting nonlinear system of ODEs is solved numerically using the implicit finite difference method (FDM). The local skin-friction coefficients and the local Nusselt numbers for different physical parameters are presented in a table.

  12. Melting phenomenon in magneto hydro-dynamics steady flow and heat transfer over a moving surface in the presence of thermal radiation

    Institute of Scientific and Technical Information of China (English)

    Reda G.Abdel-Rahman; M.M.Khader; Ahmed M.Megahed

    2013-01-01

    The Lie group method is applied to present an analysis of the magneto hydro-dynamics (MHD) steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of thermal radiation.By using the Lie group method,we have presented the transformation groups for the problem apart from the scaling group.The application of this method reduces the partial differential equations (PDEs) with their boundary conditions governing the flow and heat transfer to a system of nonlinear ordinary differential equations (ODEs) with appropriate boundary conditions.The resulting nonlinear system of ODEs is solved numerically using the implicit finite difference method (FDM).The local skin-friction coefficients and the local Nusselt numbers for different physical parameters are presented in a table.

  13. Time–frequency analysis of nonstationary complex magneto-hydro-dynamics in fusion plasma signals using the Choi–Williams distribution

    Energy Technology Data Exchange (ETDEWEB)

    Xu, L.Q.; Hu, L.Q., E-mail: lqhu@ipp.ac.cn; Chen, K.Y.; Li, E.Z.

    2013-11-15

    Highlights: • Choi–Williams distribution yields excellent time–frequency resolution for discrete signal. • CWD method provides clear time–frequency pictures of EAST and HT-7 fast MHD events. • CWD method has advantages to wavelets transform scalogram and the short-time Fourier transform spectrogram. • We discuss about how to choose the windows and free parameter of CWD method. -- Abstract: The Choi–Williams distribution is applied to the time–frequency analysis of signals describing rapid magneto-hydro-dynamic (MHD) modes and events in tokamak plasmas. A comparison is made with Soft X-ray (SXR) signals as well as Mirnov signal that shows the advantages of the Choi–Williams distribution over both continuous wavelets transform scalogram and the short-time Fourier transform spectrogram. Examples of MHD activities in HT-7 and EAST tokamak are shown, namely the onset of coupling tearing modes, high frequency precursors of sawtooth, and low frequency MHD instabilities in edge localized mode (ELM) free in H mode discharge.

  14. 一种小型电磁力驱动流体混合器的特性%Characteristics of Minute Magneto Hydro-dynamic Mixer

    Institute of Scientific and Technical Information of China (English)

    郭春海; 谭俊杰; 任登凤; 张旺龙

    2011-01-01

    To improve the mixing efficiency ,a minute magneto hydro dynamic(MHD) mixer is designed.The characteristics of the mixer are studied theoretically and experimentally. The mixer is fabricated with an ordinary brass and polycarbonate plate by the conventional machining method. The fluid used in the study is a bluestone solution. The particle image velocimetry technique is used in the experiment,and the fluorescent power is added into the solution to visualize the flowing and stirring. The experimental result is analyzed using the data acquisition and processing system. The velocity distribution of the flow field is obrained. The theoretical model of the mixer is established and a numerical simulation is done. The results are analyzed ,being in good agreement with the experimental results.%为了提高混合效率,该文设计了一种小型的电磁动力驱动(MHD)混合器,对其混合特性进行了理论分析和实验研究.该混合器由聚碳酸脂和黄铜采用常规方法加工而成.研究液体为硫酸铜溶液,采用粒子图像测速技术进行实验,在实验过程中为观察溶液的流动混合搅拌过程,溶液中加入荧光粉作为示踪粒子,并通过数据采集和处理系统对实验结果进行分析,得到流场的速度分布.建立该混合器的理论模型,在实验的基础上进行数值模拟,并对结果进行分析比较,模拟结果与实验结果相吻合.

  15. Edge element method for 3D numerical analysis of magneto-hydro dynamics solder device%磁流体钎焊复杂电磁过程边棱元法3D模拟分析

    Institute of Scientific and Technical Information of China (English)

    国宁; Stoimen Balinov; 宋乐平

    2012-01-01

    The electromagnetic field state of MHD welding process is difficult to determine. 3D numerical analysis of the electromagnetic field in a magneto-hydro dynamic device for soldering the winding to the commutator of electric machines was carried out by means of the edge element method. The very good convergence of numerical process and the accuracy of the obtained results show that the edge element method is suitable for studying the electromagnetic processes in devices with complex geometry and non-linear properties of materials.%磁流体动力钎焊设备主要用于电机换向器绕组线圈的焊接,焊接过程中电磁场的状态很难测定,采用边棱元法对其焊接过程进行3D数值模拟分析.数值模拟过程和结果能与实际结果达到很高精度的匹配.边棱元3D数值模拟方法可以成功应用在复杂几何形状的设备和非线性特性材料的电磁过程研究.

  16. 反场构形的二维磁流体力学描述%Two-dimensional magneto-hydro dynamic description of field reversed configuration

    Institute of Scientific and Technical Information of China (English)

    李璐璐; 张华; 杨显俊

    2014-01-01

    磁化靶聚变技术作为实现纯聚变的一种途径,不需要惯性约束聚变的高初始密度(约1026 cm-3),也不需要磁约束聚变的长约束时间(秒量级),可能是一种实现纯聚变更低廉更有效的途径。开发了一个二维磁流体力学模拟程序MPF-2D,用于描述反场构形的形成过程。采用该程序对美国洛斯阿拉莫斯国家实验室在反场构形形成装置上形成反场构形的实验进行了二维模拟和分析,理论值与实验值符合得较好;同时也对中国工程物理研究院流体物理研究所设计的“荧光-1”实验装置上形成的反场构形进行了模拟与评估,结果表明该装置上的反场构形基本达到设计指标。%Magnetized target fusion (MTF) is an alternative approach to fusion, of which the plasma lifetime and density are those between inertial confinement fusion and magnetic confinement fusion. Field-reversed configuration (FRC) is a candidate target plasma of MTF. In this paper, a two-dimensional magneto-hydrodynamic code MPF-2D is developed, and it is used to simulate the formation process of FRC on experimental devices FRX series at Los Alamos National Laboratory. In addition, design parameters of FRC on“Yingguang-1”device are also evaluated, which will be constructed in 2015 at the Institute of Fluid Physics, China Academy of Engineering Physics.

  17. Dynamic Characteristics of Magneto-Fluid Supports

    Directory of Open Access Journals (Sweden)

    V. A. Chernobai

    2008-01-01

    Full Text Available The paper considers a vibro-protective magneto-fluid support that uses elastic properties of magnetic fluid with a free surface in magnetic field.The paper has experimentally revealed that the analyzed structure is characterized by better noise absorbing characteristics.The conducted experiments have made it possible to conclude that there is a possibility to use vibro-protective magneto-fluid supports within the frequency range from 0 to 300 Hz, amplitudes up to 2 mm and unit load up to 2,5 · 10 4 Н/м².

  18. Introduction to Magneto-Fluid-Dynamics for Aerospace Applications

    Science.gov (United States)

    2004-07-08

    incisive understanding is strongly dependent on how knowledge is accumulated and transferred in times. The growth of magneto- fluid-dynamics is not...S. Goldstein, Lectures on Fluid Mechanics (Interscience Publishers Ltd, London, 1960). [15] B. Finzi, Principio d’Azione Stazionaria

  19. Dynamic effects in reversible hydro systems towards safety solutions

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, Pedro A.; Ramos, Helena M. [Civil Engineering Department and CEHIDRO, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001, Lisbon (Portugal)

    2010-07-01

    The purpose of this paper is to establish general strategies to evaluate the dynamic effects occurring in reversible hydro systems (i.e. turbine/pumping) with long penstocks resulting from the regular operation of the hydro equipments and, most significantly, from accidental events. It is of great importance these particular aspects are considered in the early stages of a design, in order to ensure the best technical, economical and safety operation for each developed solution. This work presents two complementary approaches to the study of dynamic effects associated to reversible hydro systems based on a parametric analysis and a simulation-based procedure, as well as in the definition of design and operation rules to guarantee a safe solution. The first approach establishes the dynamic behavior of the system by means of a parametric analysis of the hydraulic and the hydro mechanical aspects associated to system operation. Based on this methodology, it is possible to estimate the maximum upsurge, the flow variation under turbogenerators runaway conditions and a valve manoeuvre. The second approach consists in the implementation of a numerical model that simulates accurately enough, the interaction between different components of the system during transient flow regimes associated to the hydropower load rejection, pumps shutdown, actuation of upsurge protection devices and wave propagations along the all system. This methodology gathers the necessary tools for the computational transient analysis of a complex reversible system.

  20. Numerical simulation of hydro-elastic problems with smoothed particle hydro-dynamics method

    Institute of Scientific and Technical Information of China (English)

    刘谋斌; 邵家儒; 李慧琦

    2013-01-01

    Violent free surface flows with strong fluid-solid interactions can produce a tremendous pressure load on structures, resu-lting in elastic and even plastic deformations. Modeling hydro-elastic problems with structure deformations and a free surface break-up is difficult by using routine numerical methods. This paper presents an improved Smoothed Particle Hydrodynamics (SPH) method for modeling hydro-elastic problems. The fluid particles are used to model the free surface flows governed by Navier-Stokes equations, and the solid particles are used to model the dynamic movement and deformation of the elastic solid objects. The impro-ved SPH method employs a Kernel Gradient Correction (KGC) technique to improve the computational accuracy and a Fluid-Solid Interface Treatment (FSIT) algorithm with the interface fluid and solid particles being treated as the virtual particles against their counterparts and a soft repulsive force to prevent the penetration and a corrective density approximation scheme to remove the nume-rical oscillations. Three typical numerical examples are simulated, including a head-on collision of two rubber rings, the dam break with an elastic gate and the water impact onto a forefront elastic plate. The obtained SPH results agree well with experimental obse-rvations and numerical results from other sources.

  1. A dynamic magneto-optical trap for atom chips

    CERN Document Server

    Rushton, Jo; Bateman, James; Himsworth, Matt

    2016-01-01

    We describe a dynamic magneto-optical trap (MOT) suitable for the use with vacuum systems in which optical access is limited to a single window. This technique facilitates the long-standing desire of producing integrated atom chips, many of which are likely to have severely restricted optical access compared with conventional vacuum chambers. This "switching-MOT" relies on the synchronized pulsing of optical and magnetic fields at audio frequencies. The trap's beam geometry is obtained using a planar mirror surface, and does not require a patterned substrate or bulky optics inside the vacuum chamber. Central to the design is a novel magnetic field geometry that requires no external quadrupole or bias coils which leads toward a very compact system. We have implemented the trap for $^{85}$Rb and shown that it is capable of capturing 2 million atoms and directly cooling below the Doppler temperature.

  2. A dynamic magneto-optical trap for atom chips

    Science.gov (United States)

    Rushton, Jo; Roy, Ritayan; Bateman, James; Himsworth, Matt

    2016-11-01

    We describe a dynamic magneto-optical trap (MOT) suitable for the use with vacuum systems in which optical access is limited to a single window. This technique facilitates the long-standing desire of producing integrated atom chips, many of which are likely to have severely restricted optical access compared with conventional vacuum chambers. This ‘switching-MOT’ relies on the synchronized pulsing of optical and magnetic fields at audio frequencies. The trap’s beam geometry is obtained using a planar mirror surface, and does not require a patterned substrate or bulky optics inside the vacuum chamber. Central to the design is a novel magnetic field geometry that requires no external quadrupole or bias coils which leads toward a very compact system. We have implemented the trap for 85Rb and shown that it is capable of capturing 2 million atoms and directly cooling below the Doppler temperature.

  3. 爆轰驱动固体套筒压缩磁场计算及准等熵过程分析∗%Magneto-hydro dynamic calculation of magnetic flux compression with explosion driven solid liners and analysis of quasi-isentropic pro cess

    Institute of Scientific and Technical Information of China (English)

    赵继波; 孙承纬; 谷卓伟; 赵剑衡; 罗浩

    2015-01-01

    Magnetic cumulative generator (MC-1) is a kind of high energy density dynamic device. A liner is driven by a cylindrical explosive implosion to compress the magnetic flux preset in the cavity. Then the chemical energy is converted into magnetic one, which is cumulated nearby the axis to form ultra-intense magnetic field used to load sample in non-touch manner. This loading technique can bring higher pressure and relatively low elevated temperature in the sample and has a very high-degree isentropy in the course of compression. The configuration magneto-hydrodynamic code SSS/MHD is used to develop one-dimensional magneto-hydrodynamic calculation of magnetic flux compression with explosion driven solid liner. The calculation results of magnetic field in cavity and velocity of inner wall of sample tube are obtained and accord with the magnetic field measured by probe and the velocity measured by laser interference. The buckling and Bell-Plesset instabilization produced by linearly compressing magnetic field are shown through frame photography. The change laws of magnetic diffusion, eddy current and magnetic pressure in liner and sample tube are analyzed, which show that the magnetic field and pressure and eddy near to cavity in the sample tube are all higher than the ones in the liner with the same distance to cavity. The balance between the electromagnetism force and implosion action and the difference between sample tube and liner velocities are the main reasons under imploding movement. The change of isentropic increment with compression degree at the same location, whose distance is 0.05 mm to magnetic cavity in the sample tube, is discussed. The result indicates that the ratio of the maximum increment to specific heat of sample tube material is about 10%, which shows that the process of compression magnetic flux with explosion is quasi-isentropic. In general, SSS/MHD code can reveal in depth the physic images which are difficult to measure or observe in the

  4. Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Magneto-Dielectric Nanostructures

    Directory of Open Access Journals (Sweden)

    Ivan S. Maksymov

    2015-04-01

    Full Text Available A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin waves. Moreover, readers interested in a new, rapidly emerging field of all-dielectric nanophotonics will find a section about all-magneto-dielectric nanostructures.

  5. A fully dynamic magneto-rheological fluid damper model

    Science.gov (United States)

    Jiang, Z.; Christenson, R. E.

    2012-06-01

    Control devices can be used to dissipate the energy of a civil structure subjected to dynamic loading, thus reducing structural damage and preventing failure. Semiactive control devices have received significant attention in recent years. The magneto-rheological (MR) fluid damper is a promising type of semiactive device for civil structures due to its mechanical simplicity, inherent stability, high dynamic range, large temperature operating range, robust performance, and low power requirements. The MR damper is intrinsically nonlinear and rate-dependent, both as a function of the displacement across the MR damper and the command current being supplied to the MR damper. As such, to develop control algorithms that take maximum advantage of the unique features of the MR damper, accurate models must be developed to describe its behavior for both displacement and current. In this paper, a new MR damper model that includes a model of the pulse-width modulated (PWM) power amplifier providing current to the damper, a proposed model of the time varying inductance of the large-scale 200 kN MR dampers coils and surrounding MR fluid—a dynamic behavior that is not typically modeled—and a hyperbolic tangent model of the controllable force behavior of the MR damper is presented. Validation experimental tests are conducted with two 200 kN large-scale MR dampers located at the Smart Structures Technology Laboratory (SSTL) at the University of Illinois at Urbana-Champaign and the Lehigh University Network for Earthquake Engineering Simulation (NEES) facility. Comparison with experimental test results for both prescribed motion and current and real-time hybrid simulation of semiactive control of the MR damper shows that the proposed MR damper model can accurately predict the fully dynamic behavior of the large-scale 200 kN MR damper.

  6. Hydro-dynamic damping theory in flowing water

    Science.gov (United States)

    Monette, C.; Nennemann, B.; Seeley, C.; Coutu, A.; Marmont, H.

    2014-03-01

    Fluid-structure interaction (FSI) has a major impact on the dynamic response of the structural components of hydroelectric turbines. On mid-head to high-head Francis runners, the rotor-stator interaction (RSI) phenomenon always has to be considered carefully during the design phase to avoid operational issues later on. The RSI dynamic response amplitudes are driven by three main factors: (1) pressure forcing amplitudes, (2) excitation frequencies in relation to natural frequencies and (3) damping. The prediction of the two first factors has been largely documented in the literature. However, the prediction of fluid damping has received less attention in spite of being critical when the runner is close to resonance. Experimental damping measurements in flowing water on hydrofoils were presented previously. Those results showed that the hydro-dynamic damping increased linearly with the flow. This paper presents development and validation of a mathematical model, based on momentum exchange, to predict damping due to fluid structure interaction in flowing water. The model is implemented as an analytical procedure for simple structures, such as cantilever beams, but is also implemented in more general ways using three different approaches for more complex structures such as runner blades: a finite element procedure, a CFD modal work based approach and a CFD 1DOF approach. The mathematical model and all three implementation approaches are shown to agree well with experimental results.

  7. Experimental nonlinear dynamical studies in cesium magneto-optical trap using time-series analysis

    Energy Technology Data Exchange (ETDEWEB)

    Anwar, M., E-mail: mamalik2000@gmail.com; Islam, R.; Faisal, M. [National Institute of Lasers and Optronics, P.O. Nilore, Islamabad 44000, PK (Pakistan); Sikandar, M.; Ahmed, M. [Pakistan Institute of Engineering and Applied Sciences, P.O. Nilore, Islamabad 44000, PK (Pakistan)

    2015-03-30

    A magneto-optical trap of neutral atoms is essentially a dissipative quantum system. The fast thermal atoms continuously dissipate their energy to the environment via spontaneous emissions during the cooling. The atoms are, therefore, strongly coupled with the vacuum reservoir and the laser field. The vacuum fluctuations as well as the field fluctuations are imparted to the atoms as random photon recoils. Consequently, the external and internal dynamics of atoms becomes stochastic. In this paper, we have investigated the stochastic dynamics of the atoms in a magneto-optical trap during the loading process. The time series analysis of the fluorescence signal shows that the dynamics of the atoms evolves, like all dissipative systems, from deterministic to the chaotic regime. The subsequent disappearance and revival of chaos was attributed to chaos synchronization between spatially different atoms in the magneto-optical trap.

  8. Hydro-Gravitational Dynamics of Planets and Dark Energy

    Directory of Open Access Journals (Sweden)

    Carl H. Gibson

    2009-01-01

    Full Text Available Self gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the 0.3 Myr transition from plasma to gas. Linear protogalaxyclusters fragment at 0.003 Mpc viscous-inertial scales along turbulent vortex lines or in spirals, as observed. The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs in million-solar-mass clumps (PGCs that become globular-star-clusters (GCs from tidal forces or dark matter (PGCs by freezing and diffusion into 0.3 Mpc halos with 97% of the galaxy mass. The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and fragments to form galaxy cluster halos. Stars and larger planets form by binary mergers of the trillion PFPs per PGC, mostly on 0.03 Mpc galaxy accretion disks. Stars deaths depend on rates of planet accretion and internal star mixing. Moderate accretion rates pro-duce white dwarfs that evaporate surrounding gas planets by spin-radiation to form planetary nebulae before Supernova Ia events, dimming some events to give systematic distance errors, the dark energy hypothesis, and overestimates of the universe age.

  9. Hydro-Gravitational-Dynamics of Planets and Dark Energy

    CERN Document Server

    Gibson, Carl H

    2008-01-01

    Self-gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD) predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the 0.3 Myr transition from plasma to gas. Linear protogalaxyclusters fragment at 0.003 Mpc viscous-inertial scales along turbulent vortex lines or in spirals, as observed. The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs) in million-solar-mass clumps (PGCs) that become globular-star-clusters (GCs) from tidal forces or dark matter (PGCs) by freezing and diffusion into 0.3 Mpc halos with 97% of the galaxy mass. The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and frag-ments to form galaxy cluster halos. Stars and larger planets form by binary mergers of the trillion PFPs per PGC on 0.03 Mpc galaxy accretion disks. Star deaths depend on rates of planet accretion and internal star mixing. Moderate accretion rates p...

  10. Nonlinear Dynamics Analysis of the Semiactive Suspension System with Magneto-Rheological Damper

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2015-01-01

    Full Text Available This paper examines dynamical behavior of a nonlinear oscillator which models a quarter-car forced by the road profile. The magneto-rheological (MR suspension system has been established, by employing the modified Bouc-Wen force-velocity (F-v model of magneto-rheological damper (MRD. The possibility of chaotic motions in MR suspension is discovered by employing the method of nonlinear stability analysis. With the bifurcation diagrams and corresponding Lyapunov exponent (LE spectrum diagrams detected through numerical calculation, we can observe the complex dynamical behaviors and oscillating mechanism of alternating periodic oscillations, quasiperiodic oscillations, and chaotic oscillations with different profiles of road excitation, as well as the dynamical evolutions to chaos through period-doubling bifurcations, saddle-node bifurcations, and reverse period-doubling bifurcations.

  11. Magneto-Hydro-Dynamics Liquid Wheel Actuator for Spacecraft Attitude Control

    Science.gov (United States)

    2017-01-26

    of electric resistances and voltage generators representing the back electromotive voltage induced by the spinning liquid through the magnetic field...public release: distribution unlimited. List of Figures 2.1 Section of an infinite annulus . . . . . . . . . . . . . . . . . . . 5 2.2 First ( top ) and...a network of elec- tric resistances and voltage generators representing the back electromotive voltage induced by the spinning liquid through the

  12. High Dynamic Magnetic Beam Current Measurements by Means of Optimised Magneto-Resistance (MR) Sensor Engineering

    CERN Document Server

    Hape, M; Ricken, W

    2005-01-01

    The GSI-FAIR project (facility for antiprotons and ion research) will comprehend DC currents up to around 5 A in the SIS 100 synchrotron and after bunch compression down to 50 ns pulse length the peak currents will reach up to 100 A. To meet these higher demands of beam current measurements new sensor techniques are foreseen. The measurement device itself will be designed in form of a clip-on ampere-meter. The air gap of the flux concentrator is assumed to be around 5 mm and thus, the estimated maximum field therein is around 30 mT for a beam current of 100 A peak. The resolution of this device is aimed to be 1 mA in beam current, corresponding to a system dynamic of around 105. This high demands of beam current measurement require more sophisticated sensor types than just using a Hall probe. The characteristics of AMR (anisotropic magneto-resistance), GMR (giant magneto-resistance) and GMI (giant magneto-impedance) sensors like hysteresis, linearity and sensitivity have been measured within the magnetic fiel...

  13. Dynamic Model for Hydro-Turbine Generator Units Based on a Database Method for Guide Bearings

    Directory of Open Access Journals (Sweden)

    Yong Xu

    2013-01-01

    Full Text Available A suitable dynamic model of rotor system is of great significance not only for supplying knowledge of the fault mechanism, but also for assisting in machine health monitoring research. Many techniques have been developed for properly modeling the radial vibration of large hydro-turbine generator units. However, an applicable dynamic model has not yet been reported in literature due to the complexity of the boundary conditions and exciting forces. In this paper, a finite element (FE rotor dynamic model of radial vibration taking account of operating conditions is proposed. A brief and practical database method is employed to model the guide bearing. Taking advantage of the method, rotating speed and bearing clearance can be considered in the model. A novel algorithm, which can take account of both transient and steady-state analysis, is proposed to solve the model. Dynamic response for rotor model of 125 MW hydro-turbine generator units in Gezhouba Power Station is simulated. Field data from Optimal Maintenance Information System for Hydro power plants (HOMIS are analyzed compared with the simulation. Results illustrate the application value of the model in providing knowledge of the fault mechanism and in failure diagnosis.

  14. Nonlinear modeling and dynamic analysis of a hydro-turbine governing system in the process of sudden load increase transient

    Science.gov (United States)

    Li, Huanhuan; Chen, Diyi; Zhang, Hao; Wang, Feifei; Ba, Duoduo

    2016-12-01

    In order to study the nonlinear dynamic behaviors of a hydro-turbine governing system in the process of sudden load increase transient, we establish a novel nonlinear dynamic model of the hydro-turbine governing system which considers the elastic water-hammer model of the penstock and the second-order model of the generator. The six nonlinear dynamic transfer coefficients of the hydro-turbine are innovatively proposed by utilizing internal characteristics and analyzing the change laws of the characteristic parameters of the hydro-turbine governing system. Moreover, from the point of view of engineering, the nonlinear dynamic behaviors of the above system are exhaustively investigated based on bifurcation diagrams and time waveforms. More importantly, all of the above analyses supply theoretical basis for allowing a hydropower station to maintain a stable operation in the process of sudden load increase transient.

  15. Spin dynamics and magneto-optical response in charge-neutral tunnel-coupled quantum dots

    Science.gov (United States)

    Gawełczyk, Michał; Machnikowski, Paweł

    2017-04-01

    We model the electron and hole spin dynamics in an undoped double quantum dot structure, considering the carrier tunneling between quantum dots. Taking the presence of an additional in-plane or tilted magnetic field into account, we enable the simulation of magneto-optical experiments, like the time-resolved Kerr rotation measurement, which are currently performed on such structures to probe the temporal spin dynamics. With our model, we reproduce the experimentally observed effect of the extension of the spin polarization lifetime caused by spatial charge separation, which may occur in structures of this type. Moreover, we provide a number of qualitative predictions concerning the necessary conditions for observation of this effect as well as about possible channels of its suppression, including the spin–orbit coupling, which leads to tunneling of carriers accompanied by a spin flip. We also consider the impact of the magnetic field tilting, which results in an interesting spin polarization dynamics.

  16. Calculating rotating hydrodynamic and magneto-hydrodynamic waves to understand magnetic effects on dynamical tides

    CERN Document Server

    Wei, Xing

    2016-01-01

    For understanding magnetic effects on dynamical tides, we study the rotating magneto-hydrodynamic (MHD) flow driven by harmonic forcing. The linear responses are analytically derived in a periodic box under the local WKB approximation. Both the kinetic and Ohmic dissipations at the resonant frequencies are calculated and the various parameters are investigated. Although magnetic pressure may be negligible compared to thermal pressure, magnetic field can be important for the first-order perturbation, e.g. dynamical tides. It is found that magnetic field splits the resonant frequency, namely the rotating hydrodynamic flow has only one resonant frequency but the rotating MHD flow has two, one positive and the other negative. In the weak field regime the dissipations are asymmetric around the two resonant frequencies and this asymmetry is more striking with a weaker magnetic field. It is also found that both the kinetic and Ohmic dissipations at the resonant frequencies are inversely proportional to the Ekman num...

  17. Dynamic performance of magneto-optical Bi-substituted rare-earth iron garnet

    Institute of Scientific and Technical Information of China (English)

    Shiguang Li; Changxi Yang; Enyao Zhang; Guofan Jin

    2005-01-01

    @@ The dynamic performances of magneto-optical Bi-substituted rare-earth iron garnet (BIG) under different external magnetic fields and at different frequencies are experimentally studied. The measurement data indicate that the Faraday rotation angle is almost proportional to the external magnetic field when the garnet is far less saturated, while there is good switch performance when it is saturated. The higher the working frequency is, the larger the saturation magnetic field and the phase delay of Faraday angle relative to the field. The saturation fields and the phase delays at different frequencies are measured. The dynamic performance of the BIG determines the performance of BIG-based optical devices. To get the better performance of such devices, the garnets with small dampness and large stiffness should be chosen elaborately.

  18. Dynamic analysis of electro- and magneto-rheological fluid dampers using duct flow models

    Science.gov (United States)

    Esteki, Kambiz; Bagchi, Ashutosh; Sedaghati, Ramin

    2014-03-01

    Magneto-rheological (MR) and electro-rheological (ER) fluid dampers provide a semi-active control mechanism for suppressing vibration responses of a structure. MR and ER fluids change their viscosity under the influence of magnetic and electrical fields, respectively, which facilitates automatic control when these fluids are used in damping devices. The existing models, namely the phenomenological models for simulating the behavior of MR and ER dampers, rely on various parameters determined experimentally by the manufacturers for each damper configuration. It is of interest to develop mechanistic models of these dampers which can be applied to various configurations so that their fundamental characteristics can be studied to develop flexible design solutions for smart structures. This paper presents a formulation for dynamic analysis of electro-rheological (ER) and magneto-rheological (MR) fluid dampers in flow and mix mode configurations under harmonic and random excitations. The procedure employs the vorticity transport equation and the regularization function to deal with the unsteady flow and nonlinear behavior of ER/MR fluid in general motion. The finite difference method has been used to solve the governing differential equations. Using the developed approach, the damping force of ER/MR dampers can be calculated under any type of excitation.

  19. Dynamic properties of magneto-sensitive elastomer cantilevers as adaptive sensor elements

    Science.gov (United States)

    Becker, T. I.; Raikher, Yu L.; Stolbov, O. V.; Böhm, V.; Zimmermann, K.

    2017-09-01

    In engineering applications, one of the actual scientific challenges is a development of sensor systems with complex adaptive behaviour and operating sensitivity. Smart materials like magneto-sensitive elastomers (MSEs) offer great potential for designing such intelligent devices, because they possess unique magnetic-field dependent properties. This paper deals with the investigation of the free vibrational behaviour displayed by cantilever beams made of MSEs containing magnetically soft particles in the presence of a uniform magnetic field. The presented setup is considered as a prototype of a sensitive unit for transforming mechanical stimuli of the base into vibrations of the MSE element, which could be converted in a facile way into electromagnetic signals for measuring and analysing. It is shown experimentally that for the MSE beams of several different lengths and compositions, the first eigenfrequency depends strongly on the strength of the applied magnetic field. The developed theoretical model extends the conventional vibrational dynamics of thin rods to allow for the ponderomotive torque induced by magneto-mechanical interactions experienced by an MSE beam. The model has two adjustable parameters that characterise the geometric configuration of the cantilever beam and its magnetic material properties. It is found that the values of these parameters are ‘universally’ valid, i.e., they provide good agreement between the theoretical eigenfrequency dependencies and the experimental results for all used MSE beams. The evidence presented ensures a good basis for further investigations of the sensitivity and amplitude-frequency characteristics of MSE vibration sensor elements.

  20. Magneto-optical cellular chip model for intracellular orientational-dynamic-activity detection

    Science.gov (United States)

    Miyashita, Y.; Iwasaka, M.; Kurita, S.; Owada, N.

    2012-04-01

    In the present study, a magneto-optical cellular chip model (MoCCM) was developed to detect intracellular dynamics in macromolecules by using magneto-optical effects. For the purpose of cell-measurement under strong static magnetic fields of up to 10 T, we constructed a cellular chip model, which was a thin glass plate with a well for a cell culture. A cell line of osteoblast MC3T3-E1 was incubated in the glass well, and the well, 0.3 mm in depth, was sealed by a cover glass when the MoCCM was set in a fiber optic system. An initial intensity change of the polarized light transmission, which dispersed perpendicular to the cell's attaching surface, was collected for 10 to 60 min, and then magnetic fields were applied parallel and perpendicular to the surface and light direction, respectively. The magnetic birefringence signals that originated from the magnetic orientation of intracellular molecules such as cytoskeletons apparently appeared when the magnetic fields were constant at 10 T. A statistical analysis with 15 experiments confirmed that the cellular components under 10 T magnetic fields caused a stronger alignment, which was transferred into polarizing light intensity that increased more than the case before exposure. Cellular conditions such as generation and cell density affected the magnetic birefringence signals.

  1. Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Dielectric Nanostructures (Review)

    CERN Document Server

    Maksymov, Ivan S

    2015-01-01

    A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optica...

  2. Singularities in Axisymmetric Free Boundaries for ElectroHydroDynamic Equations

    Science.gov (United States)

    Garcia, Mariana Smit Vega; Vărvărucă, Eugen; Weiss, Georg S.

    2016-11-01

    We consider singularities in the ElectroHydroDynamic equations. In a regime where we are allowed to neglect surface tension, and assuming that the free surface is given by an injective curve and that either the fluid velocity or the electric field satisfies a certain non-degeneracy condition, we prove that either the fluid region or the gas region is asymptotically a cusp. Our proofs depend on a combination of monotonicity formulas and a non-vanishing result by Caffarelli and Friedman. As a by-product of our analysis we also obtain a special solution with convex conical air-phase which we believe to be new.

  3. Chaotic dynamic characteristics of pressure fluctuation signals in hydro-turbine

    Energy Technology Data Exchange (ETDEWEB)

    Su, Wen Tao; An, Shi [School of Management, Harbin Institute of Technology, Harbin (China); Li, Xiao Bin; Lan, Chao Feng; Li, Feng Chen [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin (China); Wang, Jian Sheng [Ministry of Education of China, Tianjin (China)

    2016-11-15

    The pressure fluctuation characteristics in a Francis hydro-turbine running at partial flow conditions were studied based on the chaotic dynamic methods. Firstly, the experimental data of pressure fluctuations in the draft tube at various flow conditions was de-noised using lifting wavelet transformation, then, for the de-noised signals, their spectrum distribution on the frequency domain, the energy variation and the energy partition accounting for the total energy was calculated. Hereby, for the flow conditions ranging from no cavitation to severe cavitation, the chaos dynamic features of fluctuation signals were analyzed, including the temporal-frequency distribution, phase trajectory, Lyapunov exponent and Poincaré map etc. It is revealed that, the main energy of pressure fluctuations in the draft tube locates at low-frequency region. As the cavitation grows, the amplitude of power spectrum at frequency domain becomes larger. For all the flow conditions, all the maximal Lyapunov exponents are larger than zero, and they increase with the cavitation level. Therefore, it is believed that there indeed exist the chaotic attractors in the pressure fluctuation signals for a hydro-turbine.

  4. A nonlinear kinematic and dynamic modeling of Macpherson suspension systems with a magneto-rheological damper

    Science.gov (United States)

    Dutta, Saikat; Choi, Seung-Bok

    2016-03-01

    It is well known that Macpherson strut suspension systems are widely used in light and medium weight vehicles. The performance of these suspension systems can be enriched by incorporating magneto-rheological (MR) dampers and an appropriate dynamic model is required in order to find out the ride comfort and other performances properly in the sense of practical environment conditions. Therefore, in this work the kinematic and dynamic modeling of Macpherson strut suspension system with MR damper is presented and its responses are evaluated. The governing equations are formulated using the kinematic properties of the suspension system and adopting Lagrange’s equation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. The formulated mathematical model is then compared with equivalent conventional quarter car suspension model and the different dynamic responses such as the displacement of the sprung mass are compared to emphasize the effectiveness of the proposed model. Additionally, in this work the important kinematic properties of suspension system such as camber angle, king-pin angle and track width alteration, which cannot be obtained from conventional quarter car suspension model, are evaluated in time and frequency domains. Finally, vibration control responses of the proposed suspension system are presented in time and frequency domains which are achieved from the semi-active sky-hook controller.

  5. Characteristic of Soil Hydro-Physical Properties and Water Dynamics under Different Vegetation Restoration Types

    Institute of Scientific and Technical Information of China (English)

    MA Zelong; GONG Yuanbo; HU Tingxing

    2006-01-01

    By combining the observation of the soil profile at field and the chemical and physical analysis in laboratory, a study on the hydro-physical properties of soil in six different vegetation types and the dynamics of water content after rain was conducted in Wanchanggou, Guangyuan City to find out the vegetation types with effective water-conservation functions in order to serve the ecological restoration in the low hill heavy rain area upper the Jialing River. Results showed that:the hydro-physical properties of soil in the mixed Alnus cremastogyne and Cupressua Leyland forest (AcCl) were best. But in the depth of 0-20 cm. The properties of soil in the abandoned cropland (Fm) was better than that in the AcCl. The soil bulk densities varied significantly between the layers of 0-20 cm and 20-40 cm in all the six vegetation types except that in the Robinia pseudoacacia shrub forest (RpⅡ), and the changes of the maximum and the capillary moisture capacity between layers were significant only in the Fm and in the AcCl. Of these stands, the AcCl had the shortest water-absorbing period and the strongest moisture changes in the upper layer (0-15 cm). In the same stand, the deeper the soil layer, the slighter the soil moisture varied, and the longer the soil moisture accumulating process lasted.

  6. Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Hamrle, Jaroslav [Centre for Advanced Innovation Technology, VSB-Technical University of Ostrava, 708 33 Ostrava-Poruba (Czech Republic); Pistora, JaromIr [Department of Physics, VSB-Technical University of Ostrava, 708 33 Ostrava-Poruba (Czech Republic); Hillebrands, Burkard [Fachbereich Physik and Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse 56, D-67663 Kaiserslautern (Germany); Lenk, Benjamin; Muenzenberg, Markus, E-mail: jaroslav.hamrle@vsb.c [Institute of Physics, University of Goettingen, 37077 Goettingen (Germany)

    2010-08-18

    Time-resolved magneto-optical Kerr effect (MOKE) and Brillouin light scattering (BLS) spectroscopy are important techniques for the investigation of magnetization dynamics. In this paper, we analytically calculate the MOKE and BLS signals from prototypical spin-wave modes in a ferromagnetic layer. The reliability of the analytical expressions is confirmed by optically exact numerical calculations. Finally, we discuss the dependence of the MOKE and BLS signals on the ferromagnetic layer thickness.

  7. Static/dynamic Analysis of Functionally Graded and Layered Magneto-electro-elastic Plate/pipe under Hamiltonian System

    Institute of Scientific and Technical Information of China (English)

    Dai Haitao; Cheng Wei; Li Mingzhi

    2008-01-01

    The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of double sorts of variables, and the Hamilton canonical equations are established. The 3-dimensional problem of magneto-electro-elastic structure which is investigated in Euclidean space commonly is converted into symplectic system. At the same time the Lagrange system is converted into Hamiltonlan system. As an example, the dynamic characteristics of the simply supported functionally graded magneto-electro-elastic material (FGMM) plate and pipe are investigated. Finally, the problem is solved by symplectic algorithm. The results show that the physical quantifies of displace-ment, electric potential and magnetic potential etc. change continuously at the interfaces between layers under the transverse pressure while some other physical quantifies such as the stress, electric and magnetic displacement are not continuous. The dynamic stiffness is increased by the piezoelectric effect while decreased by the piezomagnetic effect.

  8. An Evaluation of Magneto Rheological Dampers for Controlling Gun Recoil Dynamics

    Directory of Open Access Journals (Sweden)

    Mehdi Ahmadian

    2001-01-01

    Full Text Available The application of magneto rheological dampers for controlling recoil dynamics is examined, using a recoil demonstrator that includes a single-shot 50 caliber BMG rifle action and a MR damper. The demonstrator is selected such that it can adequately represent the velocities that commonly occur in weapons with a recoil system, and can be used for collecting data for analyzing the effects of MR dampers on recoil dynamics. The MR damper is designed so that it can work effectively at the large velocities commonly occurring in gun recoil, and also be easily adjusted to reasonably optimize the damper performance for the recoil demonstrator. The test results show that it is indeed possible to design and use MR dampers for recoil applications, which subject the damper to relative velocities far larger than the applications that such dampers have commonly been used for (i.e., vehicle applications. Further, the results indicate that the recoil force increases and the recoil stroke decreases nonlinearly with an increase in the damping force. Also of significance is the fact that the adjustability of MR dampers can be used in a closed-loop system such that the large recoil forces that commonly occur upon firing the gun are avoided and, simultaneously, the recoil stroke is reduced. This study points to the need for several areas of research including establishing the performance capabilities for MR dampers for gun recoil applications in an exact manner, and the potential use of such dampers for a fire out of battery recoil system.

  9. Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Posada, Stephany; Mora-Navarro, Camilo; Ortiz-Bermudez, Patricia; Torres-Lugo, Madeline [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); McElhinny, Kyle M.; Evans, Paul G. [Department of Materials Science and Engineering, 1509 University Avenue, University of Wisconsin-Madison, WI 53706 (United States); Calcagno, Barbara O. [Department of General Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); Acevedo, Aldo, E-mail: aldo.acevedo@upr.edu [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico)

    2016-08-01

    developed for potential applications in dynamic cell culture • Nanoparticles displaced the LC phase transition near physiological temperature without distortion of the LC order • Magnetic particles generate heat promoting the LCE's phase transition and contactless dynamic deformations • Magneto-induced dynamic deformations < 40 °C were achieved in the presence of common cell culture media • Collagen functionalization reduced LCEs hydrophobicity and enabled the attachment and proliferation of NIH3T3 fibroblasts.

  10. SEMICONDUCTOR DEVICES Structure optimization of a uni-traveling-carrier photodiode with introduction of a hydro-dynamic model

    Science.gov (United States)

    Guoyu, Li; Yejin, Zhang; Xiaojian, Li; Lilin, Tian

    2010-10-01

    Characteristics of a uni-traveling-carrier photodiode (UTC-PD) are investigated. A hydro-dynamic model is introduced which takes into account the electrons' velocity overshoot in the depletion region, which is a more accurate high speed device than using the normal drift—diffuse model. Based on previous results, two modified UTC-PDs are presented, and an optimized device is obtained, the bandwidth of which is more than twice that of the original.

  11. Coherent control of ultracold molecule dynamics in a magneto-optical trap using chirped femtosecond laser pulses

    CERN Document Server

    Brown, B L; Walmsley, I A; Brown, Benjamin L.; Dicks, Alexander J.; Walmsley, Ian A.

    2005-01-01

    We have studied the effects of chirped femtosecond laser pulses on the formation of ultracold molecules in a Rb magneto-optical trap. We have found that application of chirped femtosecond pulses suppressed the formation of 85Rb-2 and 87Rb-2 lowest triplet state molecules in contrast to comparable non-chirped pulses, cw illumination, and background formation rates. Variation of the amount of chirp indicated that this suppression is coherent in nature, suggesting that coherent control is likely to be useful for manipulating the dynamics of ultracold quantum molecular gases.

  12. Coherent control of ultracold molecule dynamics in a magneto-optical trap by use of chirped femtosecond laser pulses.

    Science.gov (United States)

    Brown, Benjamin L; Dicks, Alexander J; Walmsley, Ian A

    2006-05-05

    We have studied the effects of chirped femtosecond laser pulses on the formation of ultracold molecules in a Rb magneto-optical trap. We have found that application of chirped femtosecond pulses suppressed the formation of (85)Rb and (87)Rb(2) a(3)sigma(+)(u) molecules in contrast to comparable nonchirped pulses, cw illumination, and background formation rates. Variation of the amount of chirp indicated that this suppression is coherent in nature, suggesting that coherent control is likely to be useful for manipulating the dynamics of ultracold quantum molecular gases.

  13. The dynamic behavior of two collinear cracks in magneto-electro-elastic composites under harmonic anti-plane shear waves

    Institute of Scientific and Technical Information of China (English)

    SUN Yu-guo; WU Lin-zhi

    2005-01-01

    The dynamic behavior of two collinear cracks in magneto-electro-elastic composites under harmonic anti-plane shear waves is studied using the Schmidt method for the permeable crack surface conditions. By using the Fourier transform, the problem can be solved with a set of triple integral equations in which the unknown variable is the jump of the displacements across the crack surfaces. In solving the triple integral equations, the jump of the displacements across the crack surface is expanded in a series of Jacobi polynomials. It can be obtained that the stress field is independent of the electric field and the magnetic flux.

  14. Development of a dynamic coupled hydro-geomechanical code and its application to induced seismicity

    Science.gov (United States)

    Miah, Md Mamun

    This research describes the importance of a hydro-geomechanical coupling in the geologic sub-surface environment from fluid injection at geothermal plants, large-scale geological CO2 sequestration for climate mitigation, enhanced oil recovery, and hydraulic fracturing during wells construction in the oil and gas industries. A sequential computational code is developed to capture the multiphysics interaction behavior by linking a flow simulation code TOUGH2 and a geomechanics modeling code PyLith. Numerical formulation of each code is discussed to demonstrate their modeling capabilities. The computational framework involves sequential coupling, and solution of two sub-problems- fluid flow through fractured and porous media and reservoir geomechanics. For each time step of flow calculation, pressure field is passed to the geomechanics code to compute effective stress field and fault slips. A simplified permeability model is implemented in the code that accounts for the permeability of porous and saturated rocks subject to confining stresses. The accuracy of the TOUGH-PyLith coupled simulator is tested by simulating Terzaghi's 1D consolidation problem. The modeling capability of coupled poroelasticity is validated by benchmarking it against Mandel's problem. The code is used to simulate both quasi-static and dynamic earthquake nucleation and slip distribution on a fault from the combined effect of far field tectonic loading and fluid injection by using an appropriate fault constitutive friction model. Results from the quasi-static induced earthquake simulations show a delayed response in earthquake nucleation. This is attributed to the increased total stress in the domain and not accounting for pressure on the fault. However, this issue is resolved in the final chapter in simulating a single event earthquake dynamic rupture. Simulation results show that fluid pressure has a positive effect on slip nucleation and subsequent crack propagation. This is confirmed by

  15. The Magneto Hydro Dynamical Model of KHz Quasi Periodic Oscillations in Neutron Star Low Mass X-ray Binaries (II)

    CERN Document Server

    Shi, Chang-Sheng; Li, Xiang-Dong

    2014-01-01

    We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model (Shi \\& Li 2009) is re-examined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636--53, 4U 1608--52, 4U 1915--15, 4U 1728--34, XTE 1807--294) with measured spins. In this model the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at low accretion rate and the twin kHz QPOs encounter a top ceiling at high accretion rate due to the restriction of innermost stable circular orbit.

  16. Thermal Balance of the Magneto-Hydro-Dynamic Pump for Recovery of Platinum Group Metals from Spent Auto Catalysts

    Directory of Open Access Journals (Sweden)

    Gil S.

    2016-03-01

    Full Text Available Every new car should be equipped with the catalyst, which limits the amount of harmful chemical compounds such as NOx, CH and CO emitted to the air. Auto catalyst consists of the ceramic or metallic carrier, on which is the layer with Platinum Group Metals playing catalytic role. There are many methods using for recovery those valuable metals from spent auto catalyst, however evry of those methods have some limitations. Proces described in the article is the modified method of metal collector, which used magnetohydrodynamic pump. Rotary electromagnetic field generates in the liquid metal rotary current, which as a consequence washing out the PGM metals from the ceramic carriers. Considering the possibilities of commercialization of the described method, the energy balance was made. From that balance the energetic efficiency of the unit was determined and the analysis of the temperature distribution was shown thermographycally.

  17. The impact of large-scale reclamation on hydro-dynamic environment-A case study of Xinghua Bay

    Science.gov (United States)

    Yu, Jing; Bao, Xianwen; Ding, Yang; Zhang, Wei; Zhou, Lingling

    2016-08-01

    A hydro-dynamic model is established on basis of MIKE21FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s-1. On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s-1. The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.

  18. Determination and modeling of the influence of the fluid-dynamics in hydro-treating bench scale plants

    Energy Technology Data Exchange (ETDEWEB)

    Burkhardt, T.

    1999-09-16

    At an industrial scale, the hydro-treating of oil fractions is carried out in multiphase fixed bed reactors. The oil and hydrogen cross the catalyst bed, usually in co-current downflow. Since the product specifications are steadily becoming more severe, the testing of new catalysts and of modified operating conditions in pilot plants becomes increasingly important. Although these pilot plants are frequently by a factor of 100 000 smaller than the industrial units, they still have to allow the up-scaling to industrial units. In the literature relatively low conversion degrees in pilot plants are frequently reported, especially in downflow. The significantly lower fluid velocities in pilot plants seem to be responsible for such differences, as the influence of fluid-dynamic non-idealities and of the extra-particle mass transfer phenomena increases with a decrease of the fluid velocities. In the present work, the influence of important fluid-dynamic non-idealities on the hydro-treating of gas oil fractions in pilot plants was examined. This was done on the one hand in experiments with different pilot plants and on the other hand by simulations with an especially developed multiphase model. The phenomena were considered as well in an isolated manner. In order to examine any interactions with the chemical reactions, they were also studied in a reactive system. This methodology was applied to the phenomena, 'axial dispersion'and 'gas-liquid mass transfer'. (author)

  19. Magneto-Optic Fiber Gratings Useful for Dynamic Dispersion Management and Tunable Comb Filtering

    Science.gov (United States)

    Wu, Bao-Jian; Lu, Xin; Qiu, Kun

    2010-06-01

    Intelligent control of dispersion management and tunable comb filtering in optical network applications can be performed by using magneto-optic fiber Bragg gratings (MFBGs). When a nonuniform magnetic field is applied to the MFBG with a constant grating period, the resulting grating response is equivalent to that of a conventional chirped grating. Under a linearly nonuniform magnetic field along the grating, a linear dispersion is achieved in the grating bandgap and the maximal dispersion slope can come to 1260 ps/nm2 for a 10-mm-long fiber grating at 1550 nm window. Similarly, a Gaussian-apodizing sampled MFBG is also useful for magnetically tunable comb filtering, with potential application to clock recovery from return-to-zero optical signals and optical carrier tracking.

  20. Dynamic behaviour of magneto-acoustic emission in a grain-oriented steel

    Science.gov (United States)

    Stupakov, A.; Perevertov, O.; Landa, M.

    2017-03-01

    Magneto-acoustic emission (MAE) in a grain-oriented electrical steel is measured in a wide range of the magnetizing frequencies fmag = 0.5 - 100 Hz at the controllable sinusoidal/triangular waveforms of the magnetic induction B(t). Magnetic field is measured directly by a Hall sensor positioned on the steel surface. Intensity of the MAE signal (rms value) follows a loss separation formula a√{fmag } +bfmag + c and reveals a linear relationship with the hysteresis loss. Number of the MAE individual pulses drops with the magnetizing frequency hyperbolically. Shape of the induction waveform at the fixed magnetizing amplitude and frequency has no visible impact on the above-mentioned behaviour. However, rms profiles of the MAE signal are driven by the field rate of change dH / dt . Integration of the MAE profiles allows to evaluate the hysteresis coercive field.

  1. Streamflow estimation using WRF-Hydro with dynamically downscaled climate variables over southern tropical Indian region

    Science.gov (United States)

    Davis, S.; Sudheer, K. P.; Gunthe, S. S.

    2015-12-01

    Indian summer monsoon rainfall (ISMR; June to September), which constitutes around 80% of India's annual rainfall, has shown an increasing trend in intensity and frequency of extreme events (Goswami et al., 2006). It is a widely recognized fact that the increasing temperature in association with anthropogenic activities can affect the hydrological cycle, which leads to extreme events. In addition a shift in extremes of the spatial pattern of ISMR has recently been observed (Ghosh et al., 2011). Such changes in rainfall on temporal and spatial scale can further affect the stream flow over a given region subsequently making water resource management a difficult task (Mondal and Mujumdar, 2015). The hydrological models used for the stream flow estimation are dependent on various climate variables as input data. These climate variables could be obtained through either observational networks or climate model outputs. Due to the scarcity of the observational data over the Indian region and the coarse resolution of global climate model output, which is used as input to hydrologic models, large uncertainties are introduced in stream flow output (Overgaard et al., 2007). In the present study we have used the Weather Research and Forecasting (WRF) model (Skamarock et al. 2008) to downscale the essential climate variables (surface temperature, precipitation, relative humidity, etc.) as an input for its coupled hydrological extension, WRF Hydro (NCAR user's guide). We will present the results obtained from the WRF-hydro simulation to estimate the stream flow over the Thamirabarani river basin in Southern Tropical Indian region. Preliminary simulations using WRF to estimate the precipitation showed the reasonable quantitative agreement with observed values. An attempt will be made to demonstrate how these results can further be used for developing flood-forecasting techniques and for local regional water resource management.

  2. Dependence of dynamic magnetization and magneto-transport properties of FeAlSi films with oblique sputtering studied via spin rectification effect

    Energy Technology Data Exchange (ETDEWEB)

    Soh, Wee Tee; Ong, C. K. [Department of Physics, Center for Superconducting and Magnetic Materials, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); Zhong, Xiaoxi, E-mail: xiaoxi.zhong@gmail.com [Department of Physics, Center for Superconducting and Magnetic Materials, National University of Singapore, 2 Science Drive 3, Singapore 117551 (Singapore); School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2014-09-15

    FeAlSi (Sendust) is known to possess excellent soft magnetic properties comparable to traditional soft magnetic alloys such as NiFe (Permalloy), while having a relatively higher resistance for lower eddy current losses. However, their dynamic magnetic and magneto-transport properties are not well-studied. Via the spin rectification effect, we electrically characterize a series of obliquely sputtered FeAlSi films at ferromagnetic resonance. The variations of the anisotropy fields and damping with oblique angle are extracted and discussed. In particular, two-magnon scattering is found to dominate the damping behavior at high oblique angles. An analysis of the results shows large anomalous Hall effect and anisotropic magneto-resistance across all samples, which decreases sharply with increasing oblique incidence.

  3. Elliptic and magneto-elliptic instabilities

    Directory of Open Access Journals (Sweden)

    Lyra Wladimir

    2013-04-01

    Full Text Available Vortices are the fundamental units of turbulent flow. Understanding their stability properties therefore provides fundamental insights on the nature of turbulence itself. In this contribution I briely review the phenomenological aspects of the instability of elliptic streamlines, in the hydro (elliptic instability and hydromagnetic (magneto-elliptic instability regimes. Vortex survival in disks is a balance between vortex destruction by these mechanisms, and vortex production by others, namely, the Rossby wave instability and the baroclinic instability.

  4. Hydro-gravitational-dynamics cosmology is crucial to astrobiology and the biological big bang at two million years

    Science.gov (United States)

    Gibson, Carl H.

    2015-09-01

    Hydro-Gravitational-Dynamics (HGD) cosmology predicts that the 1012 s (30 Kyr) H-He4 plasma protogalaxies become, by viscous fragmentation, proto-globular-star-cluster PGC clumps of a trillion small planets, at the 1013 s transition to gas. Larger planets and stars result from mergers of these hot 3000 K hydrogen planets in the PGCs. Stardust oxides of life chemicals C, N, O, Fe, Si seed the planets when the stars explode as supernovae. Hydrogen reduces the metal oxides and silicates to metal and rocky planet cores with massive hot water oceans at critical water temperature 647 K in which organic chemistry and life can develop. Because information is continually exchanged between the merging planets, they form a cosmic soup. The biological big bang occurs between 2 Myr when liquid water rains hot deep oceans in the cooling cosmos, and 8 Myr when the oceans freeze6. Thus, HGD cosmology explains the Hoyle/Wickramasinghe concept of cometary panspermia by giving a vast, hot, nourishing, cosmological primordial soup for abiogenesis, and the means for transmitting the resulting life forms and their evolving RNA/DNA mechanisms widely throughout the universe. A primordial astrophysical basis is provided for astrobiology by HGD cosmology. Concordance ΛCDMHC cosmology is rendered obsolete by the observation of complex life on Earth.

  5. Dynamic modeling, simulation and control design of an advanced micro-hydro power plant for distributed generation applications

    Energy Technology Data Exchange (ETDEWEB)

    Marquez, J.L. [Instituto de Energia Electrica, Universidad Nacional de San Juan, Av. Libertador San Martin Oeste 1109, J5400ARL San Juan (Argentina); Molina, M.G. [CONICET, Instituto de Energia Electrica, Universidad Nacional de San Juan, Av. Libertador San Martin Oeste 1109, J5400ARL San Juan (Argentina); Pacas, J.M. [Institut fuer Leistungselektronik und Elektrische Antriebe, Universitaet Siegen, Fachbereich 12 Hoelderlinstr 3, D 57068 Siegen (Germany)

    2010-06-15

    A small-scale hydropower station is usually a run-of-river plant that uses a fixed speed drive with mechanical regulation of the turbine water flow rate for controlling the active power generation. This design enables to reach high efficiency over a wide range of water flows but using a complex operating mechanism, which is in consequence expensive and tend to be more affordable for large systems. This paper proposes an advanced structure of a micro-hydro power plant (MHPP) based on a smaller, lighter, more robust and more efficient higher-speed turbine. The suggested design is much simpler and eliminates all mechanical adjustments through a novel electronic power conditioning system for connection to the electric grid. In this way, it allows obtaining higher reliability and lower cost of the power plant. A full detailed model of the MHPP is derived and a new three-level control scheme is designed. The dynamic performance of the proposed MHPP is validated through digital simulations and employing a small-scale experimental set-up. (author)

  6. Magneto-inertia confinement approach (MICA) to fusion in dynamic Z-pinch formed from a frozen deuterium-tritium tube

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Kazunari

    1988-02-01

    This paper reconsiders the magneto-inertia confinement approach to fusion in dynamic z-pinch with a new method of generating a hot plasma using a frozen deuterium-tritium (D-T) tube as an initial condition. If modern pulsed power technology can induce the high current of the order of 10 MA along the tube, the dense z-pinch plasma formed from the electro-magnetical implosion of thin tubular D-T ice with a radius of about 1 mm can satisfy the Lawson criterion for its 1 cm length.

  7. Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates.

    Science.gov (United States)

    Herrera-Posada, Stephany; Mora-Navarro, Camilo; Ortiz-Bermudez, Patricia; Torres-Lugo, Madeline; McElhinny, Kyle M; Evans, Paul G; Calcagno, Barbara O; Acevedo, Aldo

    2016-08-01

    Recently, liquid crystalline elastomers (LCEs) have been proposed as active substrates for cell culture due to their potential to attach and orient cells, and impose dynamic mechanical signals through the application of external stimuli. In this report, the preparation of anisotropic and oriented nematic magnetic-sensitized LCEs with iron oxide nanoparticles, and the evaluation of the effect of particle addition at low concentrations on the resultant structural, thermal, thermo-mechanical, and mechanical properties is presented. Phase transformations produced by heating in alternating magnetic fields were investigated in LCEs in contact with air, water, and a common liquid cell culture medium was also evaluated. The inclusion of nanoparticles into the elastomers displaced the nematic-to-isotropic phase transition, without affecting the nematic structure as evidenced by similar values of the order parameter, while reducing the maximum thermomechanical deformations. Remote and reversible deformations of the magnetic LCEs were achieved through the application of alternating magnetic fields, which induces the nematic-isotropic phase transition through nanoparticle heat generation. Formulation parameters can be modified to allow for remote actuation at values closer to the human physiological temperature range and within the range of deformations that can affect the cellular behavior of fibroblasts. Finally, a collagen surface treatment was performed to improve compatibility with NIH-3T3 fibroblast cultures, which enabled the attachment and proliferation of fibroblasts on substrates with and without magnetic particles under quiescent conditions. The LCEs developed in this work, which are able to deform and experience stress changes by remote contact-less magnetic stimulation, may allow for further studies on the effect of substrate morphology changes and dynamic mechanical properties during in vitro cell culture.

  8. Effect of angular opening on the dynamics of relativistic hydro jets

    CERN Document Server

    Monceau-Baroux, Remi; Meliani, Zakaria; 10.1051/0004-6361/201219308

    2012-01-01

    Context. Relativistic jets emerging from AGN cores transfer energy from the core to their surrounding ISM/IGM. Because jets are observed to have finite opening angles, one needs to quantify the role of conical versus cylindrical jet propagation in this energy transfer. Aims. We use FR-II AGN jets parameter with finite opening angles. We study the effect of the variation of the opening angle on the dynamics and energy transfer of the jet. We also point out how the characteristics of this external medium, such as its density profile, play a role in the dynamics. Methods. This study exploits our parallel AMR code MPI-AMRVAC with its special relativistic hydrodynamic model, incorporating an equation of state with varying effective polytropic index. We studied mildly under-dense jets up to opening angles of 10 degrees, at Lorentz factors of about 10, inspired by observations. Instantaneous quantification of the various ISM volumes and their energy content allows one to quantify the role of mixing versus shock-heat...

  9. Flow dynamics in hyper-saline aquifers: hydro-geophysical monitoring and modeling

    Science.gov (United States)

    Haaken, Klaus; Piero Deidda, Gian; Cassiani, Giorgio; Deiana, Rita; Putti, Mario; Paniconi, Claudio; Scudeler, Carlotta; Kemna, Andreas

    2017-03-01

    Saline-freshwater interaction in porous media is a phenomenon of practical interest particularly for the management of water resources in arid and semi-arid environments, where precious freshwater resources are threatened by seawater intrusion and where storage of freshwater in saline aquifers can be a viable option. Saline-freshwater interactions are controlled by physico-chemical processes that need to be accurately modeled. This in turn requires monitoring of these systems, a non-trivial task for which spatially extensive, high-resolution non-invasive techniques can provide key information. In this paper we present the field monitoring and numerical modeling components of an approach aimed at understanding complex saline-freshwater systems. The approach is applied to a freshwater injection experiment carried out in a hyper-saline aquifer near Cagliari (Sardinia, Italy). The experiment was monitored using time-lapse cross-hole electrical resistivity tomography (ERT). To investigate the flow dynamics, coupled numerical flow and transport modeling of the experiment was carried out using an advanced three-dimensional (3-D) density-driven flow-transport simulator. The simulation results were used to produce synthetic ERT inversion results to be compared against real field ERT results. This exercise demonstrates that the evolution of the freshwater bulb is strongly influenced by the system's (even mild) hydraulic heterogeneities. The example also highlights how the joint use of ERT imaging and gravity-dependent flow and transport modeling give fundamental information for this type of study.

  10. Magneto-optical metamaterial

    CERN Document Server

    Sadatgol, Mehdi; Forati, Ebrahim; Levy, Miguel; Guney, Durdu O

    2015-01-01

    We propose a new class of metamaterials called magneto-optical metamaterials that offer enhanced angle of rotation in polarization compared to bulk magneto-optical materials. In the proposed approach, the permittivity tensor of a magneto-optical material is tailored by embedded wire meshes behaving as artificial plasma. We have shown that the angle of rotation in the magneto-optical metamaterial can be enhanced up to 9 times compared to bulk magneto-optical material alone while the polarization extinction ratio remains below -20dB and insertion loss is less than 1.5dB.

  11. Synthesis of Ultradisperse Carbon Dioxide Powder with Plasma-Dynamic Method in the Coaxial Magneto-Plasma Accelerator

    Directory of Open Access Journals (Sweden)

    Golyanskaya Evgeniya. O.

    2016-01-01

    Full Text Available One of the most promising trends in modern physics is the high-temperature superconductivity. Analysis of high-temperature superconductors revealed that almost all of them are complex copper-based oxides. Studies have shown the possibility of using them for the synthesis of coaxial magneto accelerator. Studies have identified the products synthesized soot: Cu, Cu2O, CuO, their shape and size. Also been deciphered and electron microscopy confirmed the composition of the nanopowder obtained in laboratory conditions.

  12. Numerical approach for a system of second kind Volterra integral equations in magneto-electro-elastic dynamic problems

    Institute of Scientific and Technical Information of China (English)

    DING Hao-jiang; WANG Hui-ming

    2005-01-01

    The elastodynamic problems of magneto-electro-elastic hollow cylinders in the state ofaxisymmetric plane strain case can be transformed into two Volterra integral equations of the second kind about two functions with respect to time. Interpolation functions were introduced to approximate two unknown functions in each time subinterval and two new recursive formulae are derived. By using the recursive formulae, numerical results were obtained step by step. Under the same time step, the accuracy of the numerical results by the present method is much higher than that by the traditional quadrature method.

  13. Modeling of fluid injection and withdrawal induced fault activation using discrete element based hydro-mechanical and dynamic coupled simulator

    Science.gov (United States)

    Yoon, Jeoung Seok; Zang, Arno; Zimmermann, Günter; Stephansson, Ove

    2016-04-01

    Operation of fluid injection into and withdrawal from the subsurface for various purposes has been known to induce earthquakes. Such operations include hydraulic fracturing for shale gas extraction, hydraulic stimulation for Enhanced Geothermal System development and waste water disposal. Among these, several damaging earthquakes have been reported in the USA in particular in the areas of high-rate massive amount of wastewater injection [1] mostly with natural fault systems. Oil and gas production have been known to induce earthquake where pore fluid pressure decreases in some cases by several tens of Mega Pascal. One recent seismic event occurred in November 2013 near Azle, Texas where a series of earthquakes began along a mapped ancient fault system [2]. It was studied that a combination of brine production and waste water injection near the fault generated subsurface pressures sufficient to induced earthquakes on near-critically stressed faults. This numerical study aims at investigating the occurrence mechanisms of such earthquakes induced by fluid injection [3] and withdrawal by using hydro-geomechanical coupled dynamic simulator (Itasca's Particle Flow Code 2D). Generic models are setup to investigate the sensitivity of several parameters which include fault orientation, frictional properties, distance from the injection well to the fault, amount of fluid withdrawal around the injection well, to the response of the fault systems and the activation magnitude. Fault slip movement over time in relation to the diffusion of pore pressure is analyzed in detail. Moreover, correlations between the spatial distribution of pore pressure change and the locations of induced seismic events and fault slip rate are investigated. References [1] Keranen KM, Weingarten M, Albers GA, Bekins BA, Ge S, 2014. Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection, Science 345, 448, DOI: 10.1126/science.1255802. [2] Hornbach MJ, DeShon HR

  14. Magneto-Hydro Dynamic Flow and Heat Transfer of Nonnewtonian Power-Law Fluid Over a Non-Linear Stretching Surface with Viscous Dissipation

    Directory of Open Access Journals (Sweden)

    Kishan N.

    2014-05-01

    Full Text Available A fluid flow and heat transfer analysis of an electrically conducting non-Newtonian power law fluid flowing over a non-linear stretching surface in the presence of a transverse magnetic field taking into consideration viscous dissipation effects is investigated. The stretching velocity, the temperature and the transverse magnetic field are assumed to vary in a power-law with the distance from the origin. The flow is induced due to an infinite elastic sheet which is stretched in its own plane. The governing equations are reduced to non-linear ordinary differential equations by means of similarity transformations. By using quasi-linearization techniques first linearize the non linear momentum equation is linearized and then the coupled ordinary differential equations are solved numerically by an implicit finite difference scheme. The numerical solution is found to be dependent on several governing parameters, including the magnetic field parameter, power-law index, Eckert number, velocity exponent parameter, temperature exponent parameter, modified Prandtl number and heat source/sink parameter. A systematic study is carried out to illustrate the effects of these parameters on the fluid velocity and the temperature distribution in the boundary layer. The results for the local skin-friction coefficient and the local Nusselt number are tabulated and discussed.

  15. 磁控进气道二维性能计算%Numericai simulation of the two-dimensional magneto-hydro-dynamic controlled inlet

    Institute of Scientific and Technical Information of China (English)

    郑小梅; 徐大军; 蔡国飙

    2009-01-01

    超燃冲压发动机进气道通常都足针对某一特定的马赫数进行设计的,当飞行马赫数不在设计马赫数时发动机性能急剧降低,磁控进气道的应用很有可能解决这一技术难题.对磁控进气道内的流动情况进行了二维数值模拟.飞行马赫数大于设计马赫数时采用磁控进气道可以调整激波位置使激波回到设计点,并减小燃烧室人口处的马赫数.分析了霍尔效应对磁控进气道性能的影响,结果表明分段电极可以有效减小霍尔效应的不利影响.

  16. Regime of aggregate structures and magneto-rheological characteristics of a magnetic rod-like particle suspension: Monte Carlo and Brownian dynamics simulations

    Science.gov (United States)

    Okada, Kazuya; Satoh, Akira

    2017-09-01

    In the present study, we address a suspension composed ferromagnetic rod-like particles to elucidate a regime change in the aggregate structures and the magneto-rheological characteristics. Monte Carlo simulations have been employed for investigating the aggregate structures in thermodynamic equilibrium, and Brownian dynamics simulations for magneto-rheological features in a simple shear flow. The main results obtained here are summarized as follows. For the case of thermodynamic equilibrium, the rod-like particles aggregate to form thick chain-like clusters and the neighboring clusters incline in opposite directions. If the external magnetic field is increased, the thick chain-like clusters in the magnetic field direction grow thicker by adsorbing the neighboring clusters that incline in the opposite direction. Hence, a significant phase change in the particle aggregates is not induced by an increase in the magnetic field strength. For the case of a simple shear flow, even a weak shear flow induces a significant regime change from the thick chain-like clusters of thermodynamic equilibrium into wall-like aggregates composed of short raft-like clusters. A strong external magnetic field drastically changes these aggregates into wall-like aggregates composed of thick chain-like clusters rather than the short raft-like clusters. The internal structure of these aggregates is not strongly influenced by a shear flow, and the formation of the short raft-like clusters is maintained inside the aggregates. The main contribution to the net viscosity is the viscosity component due to magnetic particle-particle interaction forces in relation to the present volumetric fraction. Hence, a larger magnetic interaction strength and also a stronger external magnetic field give rise to a larger magneto-rheological effect. However, the dependence of the viscosity on these factors is governed in a complex manner by whether or not the wall-like aggregates are composed mainly of short raft

  17. Observation of Transient Overcritical Currents in YBCO Thin Films using High-Speed Magneto-Optical Imaging and Dynamic Current Mapping

    Science.gov (United States)

    Wells, Frederick S.; Pan, Alexey V.; Golovchanskiy, Igor A.; Fedoseev, Sergey A.; Rozenfeld, Anatoly

    2017-01-01

    The dynamics of transient current distributions in superconducting YBa2Cu3O7−δ thin films were investigated during and immediately following an external field ramp, using high-speed (real-time) Magneto-Optical Imaging and calculation of dynamic current profiles. A number of qualitatively unique and previously unobserved features are seen in this novel analysis of the evolution of supercurrent during penetration. As magnetic field ramps up from zero, the dynamic current profile is characterized by strong peaks, the magnitude of which exceed the conventional critical current density (as determined from static current profiles). These peaks develop close to the sample edges, initially resembling screening currents but quickly growing in intensity as the external field increases. A discontinuity in field and current behaviour is newly observed, indicating a novel transition from increasing peak current toward relaxation behaviour. After this transition, the current peaks move toward the centre of the sample while reducing in intensity as magnetic vortices penetrate inward. This motion slows exponentially with time, with the current distribution in the long-time limit reducing to the expected Kim-model profile. PMID:28067331

  18. Observation of Transient Overcritical Currents in YBCO Thin Films using High-Speed Magneto-Optical Imaging and Dynamic Current Mapping.

    Science.gov (United States)

    Wells, Frederick S; Pan, Alexey V; Golovchanskiy, Igor A; Fedoseev, Sergey A; Rozenfeld, Anatoly

    2017-01-09

    The dynamics of transient current distributions in superconducting YBa2Cu3O7-δ thin films were investigated during and immediately following an external field ramp, using high-speed (real-time) Magneto-Optical Imaging and calculation of dynamic current profiles. A number of qualitatively unique and previously unobserved features are seen in this novel analysis of the evolution of supercurrent during penetration. As magnetic field ramps up from zero, the dynamic current profile is characterized by strong peaks, the magnitude of which exceed the conventional critical current density (as determined from static current profiles). These peaks develop close to the sample edges, initially resembling screening currents but quickly growing in intensity as the external field increases. A discontinuity in field and current behaviour is newly observed, indicating a novel transition from increasing peak current toward relaxation behaviour. After this transition, the current peaks move toward the centre of the sample while reducing in intensity as magnetic vortices penetrate inward. This motion slows exponentially with time, with the current distribution in the long-time limit reducing to the expected Kim-model profile.

  19. Observation of Transient Overcritical Currents in YBCO Thin Films using High-Speed Magneto-Optical Imaging and Dynamic Current Mapping

    Science.gov (United States)

    Wells, Frederick S.; Pan, Alexey V.; Golovchanskiy, Igor A.; Fedoseev, Sergey A.; Rozenfeld, Anatoly

    2017-01-01

    The dynamics of transient current distributions in superconducting YBa2Cu3O7‑δ thin films were investigated during and immediately following an external field ramp, using high-speed (real-time) Magneto-Optical Imaging and calculation of dynamic current profiles. A number of qualitatively unique and previously unobserved features are seen in this novel analysis of the evolution of supercurrent during penetration. As magnetic field ramps up from zero, the dynamic current profile is characterized by strong peaks, the magnitude of which exceed the conventional critical current density (as determined from static current profiles). These peaks develop close to the sample edges, initially resembling screening currents but quickly growing in intensity as the external field increases. A discontinuity in field and current behaviour is newly observed, indicating a novel transition from increasing peak current toward relaxation behaviour. After this transition, the current peaks move toward the centre of the sample while reducing in intensity as magnetic vortices penetrate inward. This motion slows exponentially with time, with the current distribution in the long-time limit reducing to the expected Kim-model profile.

  20. Dysprosium magneto-optical traps

    CERN Document Server

    Youn, Seo Ho; Ray, Ushnish; Lev, Benjamin L

    2010-01-01

    Magneto-optical traps (MOTs) of highly magnetic lanthanides open the door to explorations of novel phases of strongly correlated matter such as lattice supersolids and quantum liquid crystals. We recently reported the first MOTs of the five high abundance isotopes of the most magnetic atom, dysprosium. Described here are details of the experimental technique employed for repumper-free Dy MOTs containing up to half a billion atoms. Extensive characterization of the MOTs' properties---population, temperature, loading, metastable decay dynamics, trap dynamics---is provided.

  1. Enhancing filling of interconnect deep trenches using forced convection magneto-electroplating

    Science.gov (United States)

    Said, R. A.

    2006-01-01

    Filling deep trenches and cavities is currently accomplished by copper electro-less plating technology utilizing super-conformal deposition methods. Unlike typical electrolyses processes, where an electric potential is applied between the anodes to activate the plating reaction, electro-less plating relies on chemical agents to activate deposition. To achieve super-conformal deposition, special electrolytic paths must be used. This poses a challenge to the fabrication of narrower trenches, and thus requires the development of other deposition schemes. This work proposes an alternative solution to the filling of deep trenches that avoids the difficulties outlined above, using a forced convection magneto-electroplating method. The technique operates as in typical electrolysis processes, however, with forcing the flow of the plating electrolyte, by hydro-dynamic means, in the presence of an externally applied magnetic field. This arrangement introduces a Lorentz type of force that enhances the transport of deposit species toward desired locations, such as deep regions in interconnect trenches. The proposed method is demonstrated by filling interconnect trenches with aspect ratio as high as 3:1. Quality of samples filled using the proposed magneto-electroplating method is compared with the quality of samples filled by typical electroplating method.

  2. The helicopter dynamic stability analysis in hover condition using magneto-rheological dampers%悬停状态带磁流变减摆器直升机的动稳定性分析

    Institute of Scientific and Technical Information of China (English)

    卫丽君; 李书

    2012-01-01

    Magneto-rheological damper model suitable for helicopter air resonance and momentum theory model of hover condition involving momentum theory were built in this paper. The equations of the two models with the dynamic equations of helicopter rotor/body coupling were solved by Simulink time domain simulation method to obtain the helicopter dynamic stability influenced by Magneto-rheological damper and compared the blade flapping and lagging impacted by Magneto-rheological dampers under different voltages. It could be conclude that under a certain voltage, Magneto-rheological damper was not influenced by duel-frequent excitation, and was good at restraining the helicopter air resonance.%建立了适用于直升机悬停状态动稳定性的磁流变减摆器模型,悬停状态下动力入流模型采用动量理论模型,与直升机旋翼/机体耦合动力学方程组联立,采用Simulink时域仿真的方法计算得到磁流变减摆器对悬停状态下直升机动稳定的影响,对比了不同电压下磁流变减摆器对桨叶挥舞摆振运动的影响.结果表明:对于磁流变减摆器,施加不同电压可得到不同的阻尼力,该性质可以抑制直升机悬停状态动不稳定性.

  3. Challenging hydro-hegemony

    DEFF Research Database (Denmark)

    Wessels, Josepha Ivanka

    2015-01-01

    Hydro-hegemonic praxis defines much of Israel’s occupation that has continued since the signing of the Oslo Accords in 1993. Two empirical case studies of hydro-hegemony and counter-hegemony at local level are compared in this paper: the Israeli-occupied Golan Heights and the Israeli-occupied West...

  4. Magneto-optical multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Bader, S.D.

    1992-02-01

    Magneto-optical multilayers are of interest to the optical data storage community as a possible second-generation medium of the future. The important Co/Pt-superlattice system is introduced in this respect, and an extensive reference listing is provided to previous research. Magneto-optical modeling studies of Co/Pt are presented, and it is concluded that the interfacial Pt is magnetized and is magneto-optically active at the short wavelengths of interest ({approximately}4 eV) for applications. Magneto-optics in the ultrathin limit are discussed, and an additivity law is presented and verified experimentally utilizing data for epitaxial Fe/Ag(111) superlattices. Finally, the surface magnetic anisotropy that provides the vertical easy axes of magnetization in candidate superlattice systems is discussed and illustrated experimentally using ultrathin epitaxial films of Fe grown on a variety of substrates. It is concluded that magneto-optic multilayers will provide many stimulating basic and applied challenges in the years ahead.

  5. Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes

    CERN Document Server

    Gibson, Carl H

    2008-01-01

    Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentatio...

  6. Structure and Magneto-Optical Characteristic Study of Optical Multilayer Thin Films

    Institute of Scientific and Technical Information of China (English)

    YANG Cheng-tao

    2005-01-01

    @@ Based on the design theory of soft X-ray optical multilayer thin films and magneto-optic multilayer thin films, the metal multilayer thin films for the reflection of soft X-ray and ultraviolet ray, as well as the magneto-optic multilayer thin films for the magneto-optical memories were constructed. The metal multilayer thin films and the magneto-optic multilayer thin films were deposited with magnetron sputtering. The detail of optical reflection characteristics, layered-structure, and surface and interface characteristics were studied. At the same time,the static magneto-optical characteristics and dynamic magneto-optical characteristics of the magneto-optical disk were investigated.

  7. Low-energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu2OSeO3

    Science.gov (United States)

    Laurita, N. J.; Marcus, G. G.; Trump, B. A.; Kindervater, J.; Stone, M. B.; McQueen, T. M.; Broholm, C. L.; Armitage, N. P.

    2017-06-01

    In this paper, we present a comprehensive study of the low-energy optical magnetic response of the skyrmionic Mott insulator Cu2OSeO3 via high resolution time-domain THz spectroscopy. In zero field, a new magnetic excitation (f0=2.03 THz ) which has not been predicted by spin-wave theory is observed and shown, with accompanying time-of-flight neutron scattering experiments, to be a zone folded magnon from the R to Γ points of the Brillouin zone. Highly sensitive polarimetry experiments performed in weak magnetic fields, μ0H 5 T , we observe the magnetically active uniform mode of the ferrimagnetic field polarized phase whose dynamics as a function of field and temperature are studied. In addition to extracting a geff=2.08 ±0.03 , we observe the uniform mode to decay through a non-Gilbert damping mechanism and to possess a finite spontaneous decay rate, Γ0≈25 GHz , in the zero temperature limit. Our observations are attributed to Dzyaloshinkii-Moriya interactions, which have been proposed to be exceptionally strong in Cu2OSeO3 and are expected to impact the low-energy magnetic response of such chiral magnets.

  8. WaterHydro_LKBSPRE

    Data.gov (United States)

    Vermont Center for Geographic Information — The WaterHydro_LKBSPRE layer consists of drainage basins for water bodies of approximately five or more acres. The data was digitized from 1:24,000 (or 1:25,000)...

  9. Establishing a Dynamic Database of Blue and Fin Whale Locations from Recordings at the IMS CTBTO hydro-acoustic network. The Baleakanta Project

    Science.gov (United States)

    Le Bras, R. J.; Kuzma, H.

    2013-12-01

    Falling as they do into the frequency range of continuously recording hydrophones (15-100Hz), blue and fin whale songs are a significant source of noise on the hydro-acoustic monitoring array of the International Monitoring System (IMS) of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO). One researcher's noise, however, can be a very interesting signal in another field of study. The aim of the Baleakanta Project (www.baleakanta.org) is to flag and catalogue these songs, using the azimuth and slowness of the signal measured at multiple hydrophones to solve for the approximate location of singing whales. Applying techniques borrowed from human speaker identification, it may even be possible to recognize the songs of particular individuals. The result will be a dynamic database of whale locations and songs with known individuals noted. This database will be of great value to marine biologists studying cetaceans, as there is no existing dataset which spans the globe over many years (more than 15 years of data have been collected by the IMS). Current whale song datasets from other sources are limited to detections made on small, temporary listening devices. The IMS song catalogue will make it possible to study at least some aspects of the global migration patterns of whales, changes in their songs over time, and the habits of individuals. It is believed that about 10 blue whale 'cultures' exist with distinct vocal patterns; the IMS song catalogue will test that number. Results and a subset of the database (delayed in time to mitigate worries over whaling and harassment of the animals) will be released over the web. A traveling museum exhibit is planned which will not only educate the public about whale songs, but will also make the CTBTO and its achievements more widely known. As a testament to the public's enduring fascination with whales, initial funding for this project has been crowd-sourced through an internet campaign.

  10. Floodplain restoration on the upper Danube by re-establishing back water dynamics: first results of the hydro-geomorphological monitoring

    Science.gov (United States)

    Fischer, Peter; Hilger, Ludwig; Cyffka, Bernd

    2013-04-01

    Within the framework of a restoration project at the upper Danube, eight working groups of different scientific disciplines have been operating since 2009. They investigate the changes evoked through the accomplished restoration measures, which seek to bring back new dynamics to the floodplain and to reconnect it with the river in order to optimize flood plain ecological functioning. Main object is the identification and analysis of hydro-geomorphological processes and their impact on vegetation and fauna. Hydrology is one of the key factors determining the type and function of flood plains and thus alternating water levels are the motor of riparian ecosystems. Diverse water and groundwater levels and particularly flood events affect and support floodplain typical vegetation and animal species. All floodplain waterbodies (oxbows, floodplain ponds, backwaters and sidearms) are more or less connected by surface or subsurface waterways. Hydrological conditions are mainly influenced by the following measures: a, permanent nature orientated bypass river with a discharge of up to 5 m3/s; b, man controlled ecological flooding (discharge of up to 30 m3/s); c, groundwater drawdown in the eastern project area. These measures shall bring back "former" natural hydrological dynamics to the floodplain. They establish geomorphological processes and forms as well and create a mosaic of typical habitats. River morphology is monitored by terrestrial laser scanning analysing the so attained data sets, erosion and aggregation rates at selected undercut slopes and point bars can be detected with a high resolution. Large scale mapping by a drone and dGPS mapping are very helpful tools for identifing widespread flooding areas. Further methods such as, cross section and bed load measurements complete the research work. The aim is to link the interaction of these abiotic processes with the biotic nature and determine the importance of geomorphological disturbance for floodplain ecosystems

  11. Micro-hydro power

    Energy Technology Data Exchange (ETDEWEB)

    Fraenkel, P.; Paish, O. (IT Power, Eversley (United Kingdom)); Harvey, A.; Brown, A.; Edwards, R. (Intermediate Technology Development Group Ltd., Rugby (GB)); Bokalders, V. (Stockholm Environment Inst. (SE))

    1991-01-01

    This guide is specifically addressed to the practical needs of development workers. An overview of micro-hydro is given, and preliminary studies are discussed. Hydrology and site surveys are considered and civil works, penstocks, turbines, governing, drive systems, electrical power, basic economics, commissioning and testing, and operation and maintenance are reviewed in detail. (U.K.).

  12. Comparison of magnetic island stabilization strategies from magneto-hydrodynamic simulations

    Science.gov (United States)

    Février, O.; Maget, P.; Lütjens, H.; Beyer, P.

    2017-04-01

    The degradation of plasma confinement in tokamaks caused by magnetic islands motivates to better understand their possible suppression using electron cyclotron current drive (ECCD) and to investigate the various strategies relevant for this purpose. In this work, we evaluate the efficiency of several control methods through nonlinear simulations of this process with the toroidal magneto-hydro-dynamic (MHD) code XTOR-2F (Lütjens and Luciani 2010 J. Comput. Phys. 229 8130–43), which has been extended to incorporate in Ohm’s law a source term modeling the driven current resulting from the interaction of the EC waves with the plasma. A basic control system has been implemented in the code, allowing testing of advanced strategies that require feedback on island position or phase. We focus in particular on the robustness of the control strategies towards uncertainties that apply to the control and ECCD systems, such as the risk of misalignment of the current deposition or the possible inability to generate narrow current deposition.

  13. Numerical flow analysis of hydro power stations

    Science.gov (United States)

    Ostermann, Lars; Seidel, Christian

    2017-07-01

    For the hydraulic engineering and design of hydro power stations and their hydraulic optimisation, mainly experimental studies of the physical submodel or of the full model at the hydraulics laboratory are carried out. Partially, the flow analysis is done by means of computational fluid dynamics based on 2D and 3D methods and is a useful supplement to experimental studies. For the optimisation of hydro power stations, fast numerical methods would be appropriate to study the influence of a wide field of optimisation parameters and flow states. Among the 2D methods, especially the methods based on the shallow water equations are suitable for this field of application, since a lot of experience verified by in-situ measurements exists because of the widely used application of this method for the problems in hydraulic engineering. As necessary, a 3D model may supplement subsequently the optimisation of the hydro power station. The quality of the results of the 2D method for the optimisation of hydro power plants is investigated by means of the results of the optimisation of the hydraulic dividing pier compared to the results of the 3D flow analysis.

  14. Alstom launches new mini hydro range

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    LSTOM POWER HYDRO has announced the launch of a complete mini hydro solution. Named Mini-Aqua, the product has been developed to integrate the hydro turbine, generator and control system in a single and optimised product.

  15. Wind-hydro combinations

    Energy Technology Data Exchange (ETDEWEB)

    Stregger, D.L.; Fisher, W.H.

    1980-06-01

    A study was undertaken to investigate the technical and economic viability of a generalized system composed of a wind-electric and hydroelectric system interacting together to provide firm power to a grid, and to determine limits in the extent to which such a combination can be effected. Several scenarios were considered, including: a farm of horizontal axis wind turbines with various generator ratings, generating into a grid; the same wind turbine generator used to pump water into a hydroelectric plant reservoir; and a cursory examination of mechanical pumping with wind energy to increase the water supply of a hydroelectric project. The review of the state-of-the-art indicated that the scenarios investigated represent the most practical utility applications of wind-hydro combinations. The present state-of-the-art is more advanced for multi-megawatt horizontal axis tubines than for vertical axis wind turbines. The utilization factor, on a monthly determination, of the firm wind energy varies with the shape of the hydrograph, load and the wind regimes. Across Canada it was found to vary from a low of 79% to a maximum of 100%. The most important parameter in the economic evaluation of the break-even costs of wind-hydro generation is the cost of alternative supplies of energy. The regions of Canada where wind-hydro combinations appear to be within economic limits at present cost levels are Newfoundland, assuming a oil-fired thermal alternative, and isolated areas such as the Northwest Territories, assuming a diesel alternative. 67 refs., 12 figs., 13 tabs.

  16. FOREWORD: Focus on Magneto-Science

    Science.gov (United States)

    Tanimoto, Yoshifumi; Beaugnon, Eric; Kimura, Tsunehisa; Ozeki, Sumio

    2008-06-01

    , diamagnetic materials such as water and wood can be levitated by applying vertical magnetic fields: magnetic levitation. These phenomena are interpreted in terms of magnetic force. Although the effect of a magnetic force has been well investigated both theoretically and experimentally, before these reports it was difficult to imagine that water could be separated or levitated using magnetic fields, simply because the magnetic force generated by a tabletop electromagnet is not strong enough to demonstrate these phenomena clearly. The magnetic phenomena occurring under a 10 T field markedly differ from those under a 1 T field: strong magnetic fields of approximately 10 T present researchers with a new interdisciplinary field of science, encompassing physics, chemistry and biology, which will also be useful for technological development. Taking these benefits into account, we adopted the term 'magneto-science' (basic and applied), to refer to the investigation of magnetic field effects (MFEs) on physical, chemical and biological phenomena in order to differentiate this new interdisciplinary field from traditional ones. In consideration of the important role of magneto-science in the 21st century, this focus issue contains 16 articles selected from the International Conference on Magneto-Science (ICMS2007), which was held in Hiroshima, Japan in November 2007. The selected papers describe various studies of MFEs (≤ 16 T) in hard, soft and biological materials. Topics such as the magnetic processing of alloys or hard materials, spin chemistry and spin dynamics, magneto-electrochemistry, the magnetic processing of soft materials, the applications of magnetic fields to analysis, and magneto-biology are addressed to delineate the frontiers of magneto-science. We hope that this focus issue will help readers to understand several aspects of the frontiers of magneto-science.

  17. Lifting hydro's potential

    Science.gov (United States)

    Lihach, N.

    1980-12-01

    The advantages of hydroelectric power, in terms of capital, operating and maintenance costs and in terms of fuel and environmental considerations, are causing an upgrading of existing installations to provide more generating capacity. Hydrocapacity supplies 1/8 of the U.S. electric energy and will probably increase from 50 to 100% by the early 2000's as the price of other forms of energy rises. Ways of increasing output are: better water control, uprating of hydrogenerators, standardization of turbines, and methods of pumped hydro, an energy storage technique. An obstacle to this aim is the cumbersome licensing process of competing federal agencies which places a particular burden on small projects.

  18. Hydro-energy; Energie hydraulique

    Energy Technology Data Exchange (ETDEWEB)

    Bacher, P. [Electricite de France (EDF), 75 - Paris (France); Tardieu, B. [Coyne et Bellier, 92 - Gennevilliers (France)

    2005-07-01

    The first part of this study concerns the different type of hydraulic works. The second part presents the big hydro-energy, its advantages and disadvantages, the industrial risks, the electric power transport network, the economy and the development perspectives. The third part presents the little hydro-energy, its advantages and disadvantages, the decentralized production and the development perspectives. (A.L.B.)

  19. 75 FR 17706 - FPL Energy Maine Hydro LLC, Complainant v. Great Lakes Hydro America LLC Rumford Falls Hydro LLC...

    Science.gov (United States)

    2010-04-07

    ... Energy Regulatory Commission FPL Energy Maine Hydro LLC, Complainant v. Great Lakes Hydro America LLC Rumford Falls Hydro LLC, Respondents; Notice of Complaint March 29, 2010. Take notice that on March 26.... 803 and 825(e), FPL Energy Maine Hydro LLC (Complainant) filed a formal complaint against Great...

  20. Grey extra-deleting theory-based governor control for hydro-generator unit

    Directory of Open Access Journals (Sweden)

    Ming-dong Wang

    2015-10-01

    Full Text Available The control effect by using the conventional method is not satisfied because of the grey character caused from time-variant parameters of hydro-generator units and its governor. The grey extra-deleting control theory is applied to the governor design of hydro-generator units in this paper. After the mathematic model of hydro-generator and its governor are founded, the grey extra-deleting controller is designed and its effect is studied compared with the conventional proportional–integral–derivative governor. The simulation results indicate that the grey extra-deleting controller can improve dynamic characteristic of hydro-generator units.

  1. 竖板表面温度的变化对磁流体动力学流动的影响%Effects of Magneto Hydro Dynamic Flow Past a Vertical Plate With Variable Surface Temperature

    Institute of Scientific and Technical Information of China (English)

    I·A·阿巴斯; G·帕拉尼; 黄雅意

    2010-01-01

    在横向磁场作用下,不可压缩的粘性导电流体,流经一个半无限的竖板,完成了壁面温度变化对磁流体动力学流动的分析.假定由粘性耗散和感应磁场产生的热量可以忽略不计.无量纲的控制方程为二维非稳态耦合的非线性方程.结果显示,磁场参数对空气和水的速度有着抑制作用.

  2. 微机控制的磁流体发电机输出电路的探究%Development of Output-Circuit of Magneto-Hydro-Dynamics Power Generation Inverter Power Source with Single-Chip Microcomputer Control

    Institute of Scientific and Technical Information of China (English)

    李胜强; 王丽萍; 贡照天

    2007-01-01

    采用PICl6C74单片机为控制系统的核心,简化了控制电路,采用全桥式逆变电路,实现实验电路模型的设计.通过对部分功率转换器件的电流、电压的波形分析和仿真,证明电路设计可行,软件运行,利于调试,并提供了磁流体发电机实际应用时的部分参数模型.

  3. Study on the characteristics of a magneto-hydro-dynamic stirrer%电磁流体动力驱动流体搅拌混合器特性研究

    Institute of Scientific and Technical Information of China (English)

    刘庆明; TATTON; John; AUBRY; Nadine

    2006-01-01

    对小型电磁流体动力搅拌混合器的特性进行了理论分析和实验研究.该小型电磁动力混合器由聚碳酸脂和黄铜采用常规机械加工方法加工而成.研究采用的流体为氯化钠水溶液.为了观察流体的搅拌混合运动,在流体中加入微量微细玻璃珠作为示踪粒子.采用显微观测及图像采集技术记录流体的搅拌混合过程,用数字图像处理技术对流体速度场进行分析.建立了搅拌混合器的理论模型,并对其动力特性进行了数值分析,理论结果与实验结果相吻合.该小型电磁动力混合器已应用于微管道流动的混合控制并可应用于其它微流体控制系统中.

  4. Identification of m =2 competent mode of complex magneto-hydro-dynamics activities during internal soft disruption based on singular value decomposition and tomography of soft-X-ray emission on the HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    Xu Li-Qing; Mao Song-Tao; Duan Yan-Min; Hu Li-Qun; Li Er-Zhong; Chen Kai-Yun; Liu Zhi-Yuan; Chen Ye-Bin; Zhang Ji-Zong; Zhou Rui-Jie; Yang Mao

    2012-01-01

    In this paper,the singular value decomposition(SVD)method as a filter is applied before the tomographic inversion of soft-X-ray emission.Series of ‘filtered' signals including specific chronos and topos are obtained.(Here,chronos and topos are the decomposed spatial vectors and the decomposed temporal vectors,respectively).Given specific magnetic flux function with coupling m=1 and m=2 modes,the line-integrated soft-X-ray signals at all chords have been obtained.Then m=1 and m=2 modes have been identified by tomography of simulated ‘filtered' signals extracted by the SVD method.Finaly,using the experimental line-integrated soft-X-ray signals,m=2 competent mode of complex magnetohydrodynamics(MHD)activities during internal soft disruption is observed.This result demonstrates that m=2 mode plays an important role in internal disruption(Here,m is the poloidal mode number).

  5. Identification of m = 2 competent mode of complex magneto-hydro-dynamics activities during internal soft disruption based on singular value decomposition and tomography of soft-X-ray emission on the HT-7 tokamak

    Science.gov (United States)

    Xu, Li-Qing; Hu, Li-Qun; Li, Er-Zhong; Chen, Kai-Yun; Liu, Zhi-Yuan; Chen, Ye-Bin; Zhang, Ji-Zong; Zhou, Rui-Jie; Yang, Mao; Mao, Song-Tao; Duan, Yan-Min

    2012-05-01

    In this paper, the singular value decomposition (SVD) method as a filter is applied before the tomographic inversion of soft-X-ray emission. Series of ‘filtered’ signals including specific chronos and topos are obtained. (Here, chronos and topos are the decomposed spatial vectors and the decomposed temporal vectors, respectively). Given specific magnetic flux function with coupling m = 1 and m = 2 modes, the line-integrated soft-X-ray signals at all chords have been obtained. Then m = 1 and m = 2 modes have been identified by tomography of simulated ‘filtered’ signals extracted by the SVD method. Finaly, using the experimental line-integrated soft-X-ray signals, m = 2 competent mode of complex magnetohydrodynamics(MHD) activities during internal soft disruption is observed. This result demonstrates that m = 2 mode plays an important role in internal disruption (Here, m is the poloidal mode number).

  6. Modular small hydro configuration

    Science.gov (United States)

    1981-09-01

    Smaller sites (those under 750 kilowatts) which previously were not attractive to develop using equipment intended for application at larger scale sites, were the focal point in the conception of a system which utilizes standard industrial components which are generally available within short procurement times. Such components were integrated into a development scheme for sites having 20 feet to 150 feet of head. The modular small hydro configuration maximizes the use of available components and minimizes modification of existing civil works. A key aspect of the development concept is the use of a vertical turbine multistage pump, used in the reverse mode as a hydraulic turbine. The configuration allows for automated operation and control of the hydroelectric facilities with sufficient flexibility for inclusion of potential hydroelectric sites into dispersed storage and generation (DSG) utility grid systems.

  7. Mathematical methods in electro-magneto-elasticity

    CERN Document Server

    Bardzokas, DI; Filshtinsky, LA

    2007-01-01

    The mechanics of Coupled Fields is a discipline at the edge of modern research connecting Continuum Mechanics with Solid State Physics. It integrates the Mechanics of Continuous Media, Heat Conductivity and the theory of Electromagnetism that are usually studied separately. For an accurate description of the influence of static and dynamic loadings, high temperatures and strong electromagnetic fields in elastic media and constructive installations, a new approach is required; an approach that has the potential to establish a synergism between the above mentioned fields. Throughout the book a vast number of problems are considered: two-dimensional problems of electro-magneto-elasticity as well as static and dynamical problems for piecewise homogenous compound piezoelectric plates weakened by cracks and openings. The boundary conditions, the constructive equations and the mathematical methods for their solution are thoroughly presented, so that the reader can get a clear quantitative and qualitative understandi...

  8. A contribution to the measurement of static and dynamic properties of electromagnetomechanical inverters and their components; Ein Beitrag zur Messung statischer und dynamischer Eigenschaften von elektro-magneto-mechanischen Energiewandlern und deren Komponenten

    Energy Technology Data Exchange (ETDEWEB)

    Radler, Oliver

    2011-07-01

    Most electric actuators which are used today are electromagnetic ones. The constantly increasing quality requirements for those actuators necessitate a system of total quality management. Such an approach includes monitoring quality during design phase, during production and in the application phase. This thesis presents new methods for a versatile measurement setup to facilitate the determination of magnetic properties of soft magnetic products by using their intrinsic sensor properties. In contrast to existing methods of measurement, the magnetic properties of electromagnetic actuators may be identified under arbitrary magnetizing conditions via the actuator's field coil. Additionally, standard material specimens and a variety of ferromagnetic components are measureable in an alternating magnetic field. Due to the proposed adaptive feedback concept, a cost-efficient design of the measurement device is possible. Together with the temperature-compensated field-coil measurement method, a wide range of inductive loads can be tested. In addition to the feedback concept, all necessary electronic components are discussed. The capability of the existing prototype is demonstrated with example measurements chosen from typical application domains, as may be encountered in the development, production and application of electromagnetic actuators. Furthermore, the dynamic energy conversion of electro-magneto-mechanical actuators is analyzed under consideration of hysteresis and eddy current losses. (orig.)

  9. Underground hydro scheme for Ullapool

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Scoltish and Southern Energy has awarded a contract for a new hydropower plant Scotland, the company's first hydro project since the 1960s. The S6 million scheme will be built by Miller Civil Engineering Services Ltd.

  10. Hydro-pneumatic suspension parameters dynamical optimization design based on ride comfort%基于平顺性的油气悬架参数动态分析与优化

    Institute of Scientific and Technical Information of China (English)

    蔡祥文; 谷正气; 李伟平; 梁小波; 彭国谱

    2011-01-01

    以提高汽车行驶平顺性为目的,对油气悬架系统参数进行优化.建立油气悬架系统的二自由度1/4车辆数学模型.基于数学模型,在Matlab/Simulink软件中利用模块组合的方法建立仿真模型,并构建以车身垂直方向的加权加速度均方根值为目标函数的优化模型.优化算法采用遗传算法,通过编程将仿真模型、优化模型结合起来,实现Simulink、遗传算法对油气悬架系统参数的动态联合优化设计.利用该方法对某矿用自卸车前油气悬架设计阶段的结构参数进行优化,仿真结果表明:由该方法确定的油气悬架结构参数使车身垂直方向的加权加速度均方根值下降29.35%,加速度功率谱密度共振峰值降低23.6%,从而明显改善了汽车的行驶平顺性,同时也为其他类型的非线性悬架系统的动态优化设计提供了借鉴.%To improve vehicle ride comfort, hydro-pneumatic suspension system parameters were optimized.Mathematic model of a 2-DOF quarter-car model with hydro-pneumatic suspension system was established and then,the simulation model was developed by means of combination modules of Simulink, and optimal design model uses the root mean square value of body vertical acceleration as the objective function.Optimization using genetic algorithms, by programming the simulation model combined optimization model,and the optimal hydro-pneumatic suspension parameters were obtained after the combined optimization design between Simulink and Genetic Algorithm (GA).The structural parameters of front hydro-pneumatic of a mining dump truck were optimized during design stage using this method, the simulation results show that:the root mean square value of body vertical acceleration was brought down by 29.35% ,power spectral density of body vertical acceleration was decreased by 23.6% ,so the vehicle ride comfort can be significantly improved, which also provided references for the dynamic optimization design of

  11. Hydro-mechanical processes

    Energy Technology Data Exchange (ETDEWEB)

    Laouafa, F.; Kazmierczak, J.B. [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60 - Verneuil en Halatte (France); Armand, G. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Vaunat, J. [Catalonia UPC- Technical Univ., Barcelona (Spain); Jobmann, M.; Polster, M. [DBETEC- DBE Technology GmbH, Peine (Germany); Su, K.; Lebon, P.; Plas, F.; Armand, G.; Abou-Chakra Guery, A.; Cormery, F.; Shao, J.F.; Kondo, D. [ANDRA - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Souley, M. [Institut National de l' Environnement Industriel et des Risques (INERIS), 54 - Nancy (France); Coll, C.; Charlier, R.; Collin, F.; Gerard, P. [Liege Univ., Dept. ArGEnCo (Belgium); Xiang Ling, Li [ESV EURIDICE, SCK.CEN, Belgian Nuclear Research Centre, Mol (Belgium); Collin, F. [Liege Univ., Charge de Recherches FNRS (Belgium); Pellet, F.L.; Fabre, G. [University Joseph Fourier, Laboratory 3S-R, 38 - Grenoble (France); Garcia-Sineriz, J.L.; Rey, M. [AITEMIN - Asociacion para la Investigacion y Desarrollo Industrial de los Recursos Naturales, Madrid (Spain); Mayor, J.C. [ENRESA - Empresa Nacional des Residuos Radioactivos, Madrid (Spain); Castellanos, E.; Romero, E.; Lloret, A.; Gens, A. [Catalunya Univ. Politecnica, UPC (Spain); Villar, M.V. [CIEMAT - Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain); Chambon, R. [Laboratoire 3S, UJF-INPG-CNRS, 38 - Grenoble (France); Czaikowski, O.; Lux, K.H. [Clausthal Univ. of Technology, Professorship for Waste Disposal and Geomechanics, Clausthal-Zellerfeld (Germany); Van Geet, M.; Bastiaens, W.; Volckaert, G.; Weetjens, E.; Sillen, X. [SCK-CEN, Waste and Disposal dept., Mol (Belgium); ONDRAF/NIRAS, Brussel (Belgium); Imbert, Ch. [CEA Saclay, Dept. de Physico-Chimie (DPC/SCCME/LECBA), 91 - Gif sur Yvette (France)] [and others

    2007-07-01

    This session gathers 13 articles dealing with: three-dimensional and time stepping modelling of the whole Meuse/Haute-Marne ANDRA URL (F. Laouafa, J.B. Kazmierczak, G. Armand, J. Vaunat, M. Jobmann, M. Polster); a constitutive model for a deep argillaceous rock using Hoek-Brown criteria (K. Su, C. Chavant, M. Souley); the long term behaviour of the Boom clay: influence of viscosity on the pore pressure distribution (C. Coll, R. Charlier, X.L. Li, F. Collin); the microstructural changes induced by viscoplastic deformations in argillaceous rocks (F.L. Pellet, G. Fabre, K. Su, P. Lebon); the engineered barrier experiment at Mont Terri rock laboratory (J.L. Garcia-Sineriz, M. Rey, J.C. Mayor); the chemical influence on the Hydro-Mechanical behaviour of high-density FEBEX bentonite (E. Castellanos, M.V. Villar, E. Romero, A. Lloret, A. Gens); the influence of water exchanges on the gallery convergence (P. Gerard, R. Charlier, R. Chambon, F. Collin); a new method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times (O. Czaikowski, K.H. Lux); the installation and evaluation of a large-scale in-situ shaft seal experiment in Boom clay the RESEAL project M. Van Geet, W. Bastiaens, G. Volckaert, E. Weetjens, X. Sillen, A. Gens, M.V. Villar, Ch. Imbert, M. Filippi, F. Plas); the hydro-Mechanical response of the Callovo-Oxfordian mud-stone around a deep vertical drift (J. Vaunat, B. Garitte, A. Gens, K. Su, G. Armand); the sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite (J.F. Harrington, D.J. Birchall, P. Sellin); the comparison of the poro-elastic behavior of Meuse/Haute Marne and Tournemire argillites: effect of loading and saturation states (E. Bemer, A. Noiret, F. Homand, A. Rejeb); and the multi-scale modelling of the argillites mechanical behaviour (A. Abou-Chakra Guery, F. Cormery, K. Su, J.F. Shao, D. Kondo)

  12. Parallel, grid-adaptive approaches for relativistic hydro and magnetohydrodynamics

    NARCIS (Netherlands)

    Keppens, R.; Meliani, Z.; van Marle, A. J.; Delmont, P.; Vlasis, A.; van der Holst, B.

    2012-01-01

    Relativistic hydro and magnetohydrodynamics provide continuum fluid descriptions for gas and plasma dynamics throughout the visible universe. We present an overview of state-of-the-art modeling in special relativistic regimes, targeting strong shock-dominated flows with speeds approaching the speed

  13. Magneto-optical properties of paramagnetic superrotors

    CERN Document Server

    Milner, A A; Floß, J; Averbukh, I Sh; Milner, V

    2014-01-01

    We study the dynamics of paramagnetic molecular superrotors in an external magnetic field. Optical centrifuge is used to create dense ensembles of oxygen molecules in ultra-high rotational states. In the presence of magnetic field, the gas of centrifuged molecules becomes optically birefringent, which indicates preferential alignment of molecular axes along the field direction. The experimental observations are supported by numerical calculations and explained by means of an intuitive qualitative model, in which the effect of the applied magnetic field on the distribution of molecular axes is mediated by the spin-rotation coupling. We show that the induced magneto-rotational birefringence is more robust with respect to collisions than the rotational coherence, and that this robustness increases with increasing angular momentum.

  14. Introduction to Magneto-Hydrodynamics

    Science.gov (United States)

    Pelletier, Guy

    Magneto-Hydrodynamics (hereafter MHD) describes plasmas on large scales and more generally electrically conducting fluids. This description does not discriminate between the various fluids that constitute the medium. In laboratory, it allows to globally describe a plasma machine, for instance a toroidal nuclear fusion reactor like a Tokamak. In astrophysics it plays an essential role in the description of cosmic objects and their environments, as well as the media, such as the interstellar or the intergalactic medium. A set of phenomena are specific to MHD description. Some of them will be presented in this lecture such as the tension effect, confinement, magnetic diffusivity, magnetic field freezing, Alfvén waves, magneto-sonic waves, reconnection. A celebrated phenomenon of MHD will not be introduced in this brief lecture, namely the dynamo effect.

  15. Magneto-optical studies of magnetization processes in high-Tc superconductors structure.

    Energy Technology Data Exchange (ETDEWEB)

    Vlasko-Vlasox, V. K.

    1998-12-02

    Magneto-optical imaging is a powerful tool for nondestructive quality control and scientific research through visualization of magnetic fields around any magnetic flux or current carrying sample. It allows real time observations of domain structures and their transformations in magnetics, static and dynamic field patterns due to inhomogeneous currents in electric circuits and superconductors, and reveals distortions of the fields due to defects. In addition to qualitative pictures showing different details in the intensities of the magneto-optical images, one can obtain quantitative maps of field distributions and retrieve values of the underlying currents or magnetization variations. In this review we discuss the advantages of magneto-optics for studies of superconductors, show its place among other techniques, and report recent results in magneto-optical investigations of high temperature superconductors (HTS).

  16. Simulating Magneto-Aerodynamic Actuator

    Science.gov (United States)

    2007-12-20

    2005. 19. Boeuf, J.P., Lagmich, Y., Callegari, Th., and Pitchford , L.C., Electro- hydrodynamic Force and Acceleration in Surface Discharge, AIAA 2006...Plasmadynamics and Laser Award, 2004 AFRL Point of Contact Dr. Donald B. Paul , AFRL/VA WPAFB, OH 937-255-7329, met weekly. Dr. Alan Garscadden, AFRL/PR...validating database for numerical simulation of magneto-aerodynamic actuator for hypersonic flow control. Points of contact at the AFRL/VA are Dr. D. Paul

  17. 76 FR 4892 - Lock+ Hydro Friends Fund XXXIX, FFP Missouri 3, LLC, Allegheny 3 Hydro, LLC, Three Rivers Hydro...

    Science.gov (United States)

    2011-01-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Lock+ Hydro Friends Fund XXXIX, FFP Missouri 3, LLC, Allegheny 3 Hydro, LLC..., Pennsylvania.\\1\\ The applications were filed by Lock+ Hydro Friends Fund XXXIX, for Project No. 13740-000,...

  18. HydroImage: A New Software for HydroGeophysical and BioGeophysical Data Integration

    Science.gov (United States)

    Suribhatla, R. M.; Mok, C. M.; Kaback, D.; Chen, J.; Hubbard, S. S.

    2011-12-01

    Hydrogeophysical and biogeophysical data integration have recently emerged as cost-effective and rapid techniques for improving subsurface characterization and monitoring. In a Bayesian framework for integration, borehole based data provide prior distribution and geophysical information serve as data to update the prior through likelihood functions obtained from petrophysical models between borehole and cross-well data. We present the application of a Windows-based software called HydroImage that uses this Bayesian framework for data integration and visualization. HydroImage can be used for geostatistical estimation, geophysical tomographic inversion, petrophysical model development, and Bayesian integration. We demonstrate HydroImage using three different field datasets to estimate different subsurface states or parameters. The first example combines wellbore flowmeter test data and crosshole seismic and ground penetrating radar (GPR) data to estimate hydraulic conductivity at the DOE Bacterial Transport Site in Oyster, Virginia. The second example focuses on using time-lapse radar data to estimate moisture content dynamics associated with a desiccation test performed to remediate the deep vadose zone in Hanford, Washington. The third example demonstrates the use of spectral induced polarization data to estimate the spatial and temporal distribution of geochemical parameters that are indicative of the redox state of a contaminated aquifer.

  19. WaterHydro_WBD8VT

    Data.gov (United States)

    Vermont Center for Geographic Information — WaterHydro_WBD8VT was extracted (using ArcInfo DISSOLVE command) from WaterHydro_WBD12VT polygons, and includes Subbasins within Vermont (HUC8 level hydrologic unit...

  20. Hydro power development in Himalayas

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, V.D. [ed.] [Department of Civil Engineering, Regional Engineering College, Hamirpur (India)

    1998-12-31

    Forty papers in 8 sessions and 3 late received papers of the title conference are presented. The subjects of the sessions are (1) Investigation of hydro-power projects (6 papers); (2) Planning of hydro-power projects and financial aspects (7 papers); (3) Dam foundation problems and construction management (2 papers); (4) Underground construction (3 papers); (5) Environment impact statement (6 papers); (6) Rock engineering design, rock tunneling and power house caverns (6 papers); (7) Modern tunnel support techniques (4 papers); and (8) Operation and performance monitoring (6 refs.)

  1. MagIC: Fluid dynamics in a spherical shell simulator

    Science.gov (United States)

    Wicht, J.; Gastine, T.; Barik, A.; Putigny, B.; Yadav, R.; Duarte, L.; Dintrans, B.

    2017-09-01

    MagIC simulates fluid dynamics in a spherical shell. It solves for the Navier-Stokes equation including Coriolis force, optionally coupled with an induction equation for Magneto-Hydro Dynamics (MHD), a temperature (or entropy) equation and an equation for chemical composition under both the anelastic and the Boussinesq approximations. MagIC uses either Chebyshev polynomials or finite differences in the radial direction and spherical harmonic decomposition in the azimuthal and latitudinal directions. The time-stepping scheme relies on a semi-implicit Crank-Nicolson for the linear terms of the MHD equations and a Adams-Bashforth scheme for the non-linear terms and the Coriolis force.

  2. Dynamic off-centering of Cr$^{3+}$ ions and short-range magneto-electric clusters in in CdCr$_2$S$_4$

    CERN Document Server

    Oliveira, Gonçalo Nuno; Lopes, Armandina Lima; Amaral, João Sequeira; dos Santos, António; Ren, Yan; Mendonca, Tania Manuela; Sousa, Célia Tavares; Amaral, Vitor Sequeira; Correia, João Guilherme; Araújo, João Pedro

    2012-01-01

    The cubic spinel CdCr$_2$S$_4$ gained recently a vivid interest, given the relevance of relaxor-like dielectric behavior in its paramagnetic phase. By a singular combination of local probe techniques namely Pair Distribution Function and Perturbed Angular Correlation we firmly establish that the Cr ion plays the central key role on this exotic phenomenon, namely through a dynamic off-centering displacement of its coordination sphere. We further show that this off centering of the magnetic Cr-ion gives rise to a peculiar entanglement between the polar and magnetic degrees of freedom, stabilizing, in the paramagnetic phase, short range magnetic clusters, clearly seen in ultra-low field susceptibility measurements. Moreover, the Landau theory is here used to demonstrate that a linear coupling between the magnetic and polar order parameters is sufficient to justify the appearance of magnetic cluster in paramagnetic phase of this compound. These results open insights on the hotly debated magnetic and polar interac...

  3. Hydro investment analysis under new market conditions

    Energy Technology Data Exchange (ETDEWEB)

    Doorman, Gerard

    2010-07-01

    of new capacity. Several approaches will be considered and evaluated, among these: Development of EOPS-ST. This model combines long term stochastic optimization with a more detailed short term model that uses linear programming; Development of ProdRisk, which is based on Stochastic Dual Dynamic Programming (SDDP) that allows for more detailed modelling than the traditional SDP approach; A new method using simulator based hydro scheduling models, where first stage decisions are based on deterministic equivalents. A model of this type has been tested for the hydro thermal market problem with good results, but so far without the necessary level of detail. As a first step these approaches will be compared with respect to their potential to solve the actual tasks. The next step will be to implement necessary extensions in the most promising model. In the final phase, the enhanced model will be used for relevant analyses like capacity increases in existing plants, pumped storage, the effect of constraints etc. The presentation will include relevant examples of the impact of higher daily price variations on the operation of the Sira Kvina system. (Author)

  4. Dust Dynamics in Protoplanetary Disk Winds Driven by Magneto-Rotational Turbulence: A Mechanism for Floating Dust Grains with Characteristic Size

    CERN Document Server

    Miyake, Tomoya; Inutsuka, Shu-ichiro

    2015-01-01

    We investigate the dynamics of dust grains with various sizes in protoplanetary disk winds driven by magnetorotational turbulence, by simulating the time evolution of the dust grain distribution in the vertical direction. Small dust grains, which are well coupled to the gas, are dragged upward with the upflowing gas, while large grains remain near the midplane of a disk. Intermediate--size grains float at several scale heights from the midplane in time-averated force balance between the downward gravity and the upward gas drag. For the minimum mass solar nebula at 1 AU, dust grains with size of 20 -- 40 $\\mu m$ float at 5-10 scale heights from the midplane. Considering the dependence on the distance from the central star, smaller-size grains remain only in an outer region of the disk, while larger-size grains are distributed in a broader region. This implies that the dust depletion is expected to take place in small-to-large and inside-out manners. We also discuss the implication of our result to the observat...

  5. Dynamic off-centering of Cr3+ ions and short-range magneto-electric clusters in CdCr2S4

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Goncalo [University of Porto, Portugal; Pereira, Andre [University of Porto, Portugal; Lopes, Armandina [Centro de Fisica Nuclear da Universidade de Lisboa, Portugal; Amaral, Joao [University of Aveiro, Portugal; Moreira Dos Santos, Antonio F [ORNL; Ren, Yang [Argonne National Laboratory (ANL); Mendonca, Tania [University of Porto, Portugal; Sousa, C T [University of Porto, Portugal; Amaral, Vitor [University of Aveiro, Portugal; Correa, Joao [Instituto Tecnologico e Nuclear, Sacavem, Portugal; Araujo, Joao Pedro [University of Porto, Portugal

    2012-01-01

    The cubic spinel CdCr2S4 gained recently a vivid interest, given the relevance of relaxor-like dielectric behavior in its paramagnetic phase. By a singular combination of local probe techniques, namely, pair distribution function and perturbed angular correlation, we firmly establish that the Cr ion plays the central key role on this exotic phenomenon, namely, through a dynamic off-centering displacement of its coordination sphere. We further show that this off-centering of the magnetic Cr ion gives rise to a peculiar entanglement between the polar and magnetic degrees of freedom, stabilizing, in the paramagnetic phase, short-range magnetic clusters, clearly seen in ultralow-field susceptibility measurements. Moreover, the Landau theory is here used to demonstrate that a linear coupling between the magnetic and polar order parameters is sufficient to justify the appearance of magnetic cluster in the paramagnetic phase of this compound. These results open insights on the hotly debated magnetic and polar interaction, setting a step forward in the reinterpretation of the coupling of different physical degrees of freedom.

  6. Simulation Model of Hydro Power Plant Using Matlab/Simulink

    Directory of Open Access Journals (Sweden)

    Mousa Sattouf

    2014-01-01

    Full Text Available Hydropower has now become the best source of electricity on earth. It is produced due to the energy provided by moving or falling water. History proves that the cost of this electricity remains constant over the year. Because of the many advantages, most of the countries now have hydropower as the source of major electricity producer. The most important advantage of hydropower is that t is green energy, which mean that no air or water pollutants are produced, also no greenhouse gases like carbon dioxide are produced which makes this source of energy environment-friendly. It prevents us from the danger of global warming. This paper describes a generalized model which can be used to simulate a hydro power plant using MATLAB/SIMULINK. The plant consists of hydro turbine connected to synchronous generator, which is connected to public grid. Simulation of hydro turbine and synchronous generator can be done using various simulation tools, In this work, SIMULINK/MATLAB is favored over other tools in modeling the dynamics of a hydro turbine and synchronous machine. The SIMULINK program in MATLAB is used to obtain a schematic model of the hydro plant by means of basic function blocks. This approach is pedagogically better than using a compilation of program code as in other software programs .The library of SIMULINK software programs includes function blocks which can be linked and edited to model. The main objectives of this model are aimed to achieve some operating modes of the hydro plant and some operating tests.

  7. Quantum criticality and DBI magneto-resistance

    Science.gov (United States)

    Kiritsis, Elias; Li, Li

    2017-03-01

    We use the DBI action from string theory and holography to study the magneto-resistance at quantum criticality with hyperscaling violation. We find and analyze a rich class of scaling behaviors for the magneto-resistance. A special case describes the scaling results found in pnictides by Hayers et al in 2014 (arXiv:1412.6484).

  8. Giant magneto-resistance devices

    CERN Document Server

    Hirota, Eiichi; Inomata, Koichiro

    2002-01-01

    This book deals with the application of giant magneto-resistance (GMR) effects to electronic devices. It will appeal to engineers and graduate students in the fields of electronic devices and materials. The main subjects are magnetic sensors with high resolution and magnetic read heads with high sensitivity, required for hard-disk drives with recording densities of several gigabytes. Another important subject is novel magnetic random-access memories (MRAM) with non-volatile non-destructive and radiation-resistant characteristics. Other topics include future GMR devices based on bipolar spin transistors, spin field-effect transistors (FETs) and double-tunnel junctions.

  9. Brigham City Hydro Generation Project

    Energy Technology Data Exchange (ETDEWEB)

    Ammons, Tom B. [Energy Conservation Specialist, Port Ewen, NY (United States)

    2015-10-31

    Brigham City owns and operates its own municipal power system which currently includes several hydroelectric facilities. This project was to update the efficiency and capacity of current hydro production due to increased water flow demands that could pass through existing generation facilities. During 2006-2012, this project completed efficiency evaluation as it related to its main objective by completing a feasibility study, undergoing necessary City Council approvals and required federal environmental reviews. As a result of Phase 1 of the project, a feasibility study was conducted to determine feasibility of hydro and solar portions of the original proposal. The results indicated that the existing Hydro plant which was constructed in the 1960’s was running at approximately 77% efficiency or less. Brigham City proposes that the efficiency calculations be refined to determine the economic feasibility of improving or replacing the existing equipment with new high efficiency equipment design specifically for the site. Brigham City completed the Feasibility Assessment of this project, and determined that the Upper Hydro that supplies the main culinary water to the city was feasible to continue with. Brigham City Council provided their approval of feasibility assessment’s results. The Upper Hydro Project include removal of the existing powerhouse equipment and controls and demolition of a section of concrete encased penstock, replacement of penstock just upstream of the turbine inlet, turbine bypass, turbine shut-off and bypass valves, turbine and generator package, control equipment, assembly, start-up, commissioning, Supervisory Control And Data Acquisition (SCADA), and the replacement of a section of conductors to the step-up transformer. Brigham City increased the existing 575 KW turbine and generator with an 825 KW turbine and generator. Following the results of the feasibility assessment Brigham City pursued required environmental reviews with the DOE and

  10. An Experimental Study on the Dynamic Characteristics of Vehicle Semi-active Seat Suspension with Magneto-rheological Damper%汽车磁流变半主动座椅悬架动态特性的试验研究

    Institute of Scientific and Technical Information of China (English)

    寇发荣

    2015-01-01

    For further improving vehicle ride comfort,a magneto-rheological damper for vehicle semi-active seat suspension is developed with its damping characteristic test conducted. After analyzing its force bearing condi-tion, a dynamics model for vehicle semi-active seat suspension is built, a corresponding skyhook control strategy is devised, and a simulation is performed on the skyhook control of seat under both random and sinusoidal excitation inputs. Meanwhile a physical prototype of semi-active seat suspension with magneto-rheological damper and its test bench system are developed with corresponding bench test carried out. The results indicate that the results of simu-lation basically well agree with test data and the magneto-rheological damper developed has a good damping control-lability. Compared to original passive seat suspension, the dynamic performances of vehicle semi-active seat with magneto-rheological damper are improved by some 30% with a significant effect of vibration attenuation.%为进一步提高汽车的乘坐舒适性,研发了一种汽车座椅半主动悬架用磁流变减振器,并对其进行阻尼特性试验,通过分析其受力情况,建立了汽车半主动座椅悬架动力学模型,设计了用于座椅磁流变半主动悬架的天棚控制策略,并在随机和正弦激励输入下进行了座椅天棚控制仿真计算,试制了磁流变半主动座椅物理样机及试验台架系统,开展了磁流变半主动座椅悬架的台架试验研究。结果表明,理论仿真和试验结果基本吻合,磁流变减振器阻尼可控性好;相对于被动座椅悬架,采用磁流变半主动座椅悬架后,座椅动态性能改善了30%左右,磁流变半主动座椅悬架减振效果显著。

  11. Brigham City Hydro Generation Project

    Energy Technology Data Exchange (ETDEWEB)

    Ammons, Tom B. [Energy Conservation Specialist, Port Ewen, NY (United States)

    2015-10-31

    Brigham City owns and operates its own municipal power system which currently includes several hydroelectric facilities. This project was to update the efficiency and capacity of current hydro production due to increased water flow demands that could pass through existing generation facilities. During 2006-2012, this project completed efficiency evaluation as it related to its main objective by completing a feasibility study, undergoing necessary City Council approvals and required federal environmental reviews. As a result of Phase 1 of the project, a feasibility study was conducted to determine feasibility of hydro and solar portions of the original proposal. The results indicated that the existing Hydro plant which was constructed in the 1960’s was running at approximately 77% efficiency or less. Brigham City proposes that the efficiency calculations be refined to determine the economic feasibility of improving or replacing the existing equipment with new high efficiency equipment design specifically for the site. Brigham City completed the Feasibility Assessment of this project, and determined that the Upper Hydro that supplies the main culinary water to the city was feasible to continue with. Brigham City Council provided their approval of feasibility assessment’s results. The Upper Hydro Project include removal of the existing powerhouse equipment and controls and demolition of a section of concrete encased penstock, replacement of penstock just upstream of the turbine inlet, turbine bypass, turbine shut-off and bypass valves, turbine and generator package, control equipment, assembly, start-up, commissioning, Supervisory Control And Data Acquisition (SCADA), and the replacement of a section of conductors to the step-up transformer. Brigham City increased the existing 575 KW turbine and generator with an 825 KW turbine and generator. Following the results of the feasibility assessment Brigham City pursued required environmental reviews with the DOE and

  12. Magneto-elastic oscillator: Modeling and analysis with nonlinear magnetic interaction

    Science.gov (United States)

    Kumar, K. Aravind; Ali, Shaikh Faruque; Arockiarajan, A.

    2017-04-01

    The magneto-elastically buckled beam is a classic example of a nonlinear oscillator that exhibits chaotic motions. This system serves as a model to analyze the motion of elastic structures in magnetic fields. The system follows a sixth order magneto-elastic potential and may have up to five static equilibrium positions. However, often the non-dimensional Duffing equation is used to approximate the system, with the coefficients being derived from experiments. In few other instances, numerical methods are used to evaluate the magnetic field values. These field values are then used to approximate the nonlinear magnetic restoring force. In this manuscript, we derive analytical closed form expressions for the magneto-elastic potential and the nonlinear restoring forces in the system. Such an analytical formulation would facilitate tracing the effect of change in a parameter, such as the magnet dimension, on the dynamics of the system. The model is derived assuming a single mode approximation, taking into account the effect of linear elastic and nonlinear magnetic forces. The developed model is then numerically simulated to show that it is accurate in capturing the system dynamics and bifurcation of equilibrium positions. The model is validated through experiments based on forced vibrations of the magneto-elastic oscillator. To gather further insights about the magneto-elastic oscillator, a parametric study has been conducted based on the field strength of the magnets and the distance between the magnets and the results are reported.

  13. A disc-type magneto-rheologic fluid damper

    Institute of Scientific and Technical Information of China (English)

    祝长生

    2003-01-01

    A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper,which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magneticfield of the disc-type MR fluid damper is analysed by the finite element method ; the controllability of the disctype MR fluid damper on the dynamic behaviour of a rotor system ; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil ; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery.

  14. A disc-type magneto-rheologic fluid damper

    Institute of Scientific and Technical Information of China (English)

    祝长生

    2003-01-01

    A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery.

  15. Magneto optical trapping of Barium

    CERN Document Server

    De, S; Jungmann, K; Willmann, L

    2008-01-01

    First laser cooling and trapping of the heavy alkaline earth element barium has been achieved based on the strong 6s$^2$ $^1$S$_0$ - 6s6p $^1$P$_1$ transition for the main cooling. Due to the large branching into metastable D-states several additional laser driven transitions are required to provide a closed cooling cycle. A total efficiency of $0.4(1) \\cdot 10^{-2}$ for slowing a thermal atomic beam and capturing atoms into a magneto optical trap was obtained. Trapping lifetimes of more than 1.5 s were observed. This lifetime is shortened at high laser intensities by photo ionization losses. The developed techniques will allow to extend significantly the number of elements that can be optically cooled and trapped.

  16. Dynamics of pre-ionized fast capillary discharge

    Science.gov (United States)

    Hübner, J.; Vrba, P.; Straus, J.; Jancarek, A.; Nevrkla, M.

    2014-05-01

    The goal of this work is to determine the best conditions for pre-ionization of the nitrogen filled capillary plasma column applying an external exponentially damped or high-frequency alternating current. As we supposed, optimal pre-ionization conditions are achieved when the plasma is quiescent, motionless and isothermal, near the local thermodynamical equilibrium. At the time of optimal conditions for the pre-ionization plasma column, the main pulse is applied. This approach enables us to estimate the influence of such prepared plasma on the value of emitted energy during the main current pulse. For modeling of plasma during the pre-pulse and main pulse, the magneto-hydro-dynamics (MHD) NPINCH code [1] and the radiative-MHD Z* code [2] were used. The computer results are used for further improvement of x-ray-ultraviolet-capillary sources designed in IPP ASCR and CTU FNSPE laboratories in Prague.

  17. Norsk Hydro's R&D organisation

    OpenAIRE

    Mossige, Eldri Coll

    2011-01-01

    The problem definition for this master thesis is formulated in collaboration with Hydro representatives, and is related to Hydro’s CROC project. The thesis aims to critically review Hydro’s R&D organisation, and reveal factors which hinder synergies from being realised, and innovation to take place. A proposal for improvement has also been prepared.A broad literature study on the topic “Radical innovation in mature organisations” provides the theoretical foundation for...

  18. The road towards nonlinear magneto-plasmonics

    Science.gov (United States)

    Zheng, Wei; Liu, Xiao; Lüpke, Günter; Hanbicki, Aubrey T.; Jonker, Berend T.

    2016-10-01

    Nonlinear magneto-plasmonics (NMP) describes systems where nonlinear optics, magnetics and plasmonics are all involved. NMP can be referred to as interdisciplinary studies at the intersection of Nonlinear Plasmonics (NP), Magneto- Plasmonics (MP), and nanoscience. In NMP systems, nanostructures are the bases, Surface Plasmons (SPs) work as catalyst due to strong field enhancement effects, and the nonlinear magneto-optical Kerr effect (nonlinear MOKE) plays an important role as a characterization method. Many new effects were discovered recently, which include enhanced magnetization-induced harmonic generation, controlled and enhanced magnetic contrast, magneto-chiral effect, correlation between giant magnetroresistance (GMR) and nonlinear MOKE, etc. We review the structures, experiments, findings, and the applications of NMP.

  19. A magneto-electric quantum wheel

    CERN Document Server

    Feigel, Alexander

    2009-01-01

    Here we show that self-propulsion in quantum vacuum may be achieved by rotating or aggregating magneto-electric nano-particles. The back-action follows from changes in momentum of electro-magnetic zero-point fluctuations, generated in magneto-electric materials. This effect may provide new tools for investigation of the quantum nature of our world. It might also serve in the future as a "quantum wheel" to correct satellite orientation in space.

  20. Ultrafast magneto-photocurrents in GaAs: Separation of surface and bulk contributions

    CERN Document Server

    Schmidt, Christian B; Tarasenko, Sergey A; Bieler, Mark

    2015-01-01

    We induce ultrafast magneto-photocurrents in a GaAs crystal employing interband excitation with femtosecond laser pulses at room temperature and non-invasively separate surface and bulk contributions to the overall current response. The separation between the different symmetry contributions is achieved by measuring the simultaneously emitted terahertz radiation for different sample orientations. Excitation intensity and photon energy dependences of the magneto-photocurrents for linearly and circularly polarized excitations reveal an involvement of different microscopic origins, one of which we believe is the inverse Spin-Hall effect. Our experiments are important for a better understanding of the complex momentum-space carrier dynamics in magnetic fields.

  1. Ultra-Low-Intensity Magneto-Optical and Mechanical Effects in Metal Nanocolloids

    CERN Document Server

    Moocarme, Matthew; Vuong, Luat T

    2013-01-01

    We theoretically and numerically investigate the linear and nonlinear magneto-optical contributions to the refractive index of metal nanospheres. The analysis is in good agreement with the experimental extinction spectra of gold nanocolloid solutions, with threshold magnetic fields less than 1 mT when illuminated with light intensities less than 1 W/cm^2. Plasmonic current loops and vortex power flows provide a new framework for the dynamical interaction between material magnetization, light polarization and nano-surfaces. The photo-induced magneto-optical interaction of non-magnetic metal nanocolloids imparts significant, non-negligible torque forces in nanofluids.

  2. Advanced magneto-optical microscopy: Imaging from picoseconds to centimeters - imaging spin waves and temperature distributions (invited

    Directory of Open Access Journals (Sweden)

    Necdet Onur Urs

    2016-05-01

    Full Text Available Recent developments in the observation of magnetic domains and domain walls by wide-field optical microscopy based on the magneto-optical Kerr, Faraday, Voigt, and Gradient effect are reviewed. Emphasis is given to the existence of higher order magneto-optical effects for advanced magnetic imaging. Fundamental concepts and advances in methodology are discussed that allow for imaging of magnetic domains on various length and time scales. Time-resolved imaging of electric field induced domain wall rotation is shown. Visualization of magnetization dynamics down to picosecond temporal resolution for the imaging of spin-waves and magneto-optical multi-effect domain imaging techniques for obtaining vectorial information are demonstrated. Beyond conventional domain imaging, the use of a magneto-optical indicator technique for local temperature sensing is shown.

  3. Vibration control of a semi-active railway vehicle suspension with magneto-rheological dampers

    Directory of Open Access Journals (Sweden)

    Jong-Seok Oh

    2016-04-01

    Full Text Available This article presents vibration control performances of a semi-active railway vehicle suspension system using a magneto-rheological damper tested on the roller rig. In order to evaluate control performances, a mathematical railway vehicle model with 15 degrees of freedom is first derived to represent the lateral, yaw and roll motions of the car body, bogie frame, and wheel set, respectively. Based on the formulated model, the design parameters of magneto-rheological damper are determined to undertake a compatible comparison with dynamic performances of conventional (existing passive railway vehicle suspension system. The designed magneto-rheological damper is manufactured and its field-dependent damping force characteristics are experimentally evaluated. Subsequently, in order to enhance the ride quality of a railway vehicle suspension equipped with magneto-rheological damper, a skyhook controller associated with an extended Kalman filter is designed in a state space representation. The railway suspension system incorporated with the car body and two bogies is then experimentally set up on the roller rig in order to evaluate the ride quality. It is demonstrated from experimental realization of the controller that the ride quality of the suspension system with magneto-rheological damper can be significantly enhanced compared with the existing passive suspension system.

  4. Novel design of a self powered and self sensing magneto-rheological damper

    Science.gov (United States)

    Meftahul Ferdaus, Mohammad; Rashid, M. M.; Bhuiyan, M. M. I.; Muthalif, Asan Gani Bin Abdul; Hasan, M. R.

    2013-12-01

    Magneto-rheological (MR) dampers are semi-active control devices and use MR fluids. Magneto-rheological dampers have successful applications in mechatronics engineering, civil engineering and numerous areas of engineering. At present, traditional MR damper systems, require a isolated power supply and dynamic sensor. This paper presents the achievability and accuracy of a self- powered and self-sensing magneto-rheological damper using harvested energy from the vibration and shock environment in which it is deployed and another important part of this paper is the increased yield stress of the Magneto rheological Fluids. Magneto rheological fluids using replacement of glass beads for Magnetic Particles to surge yield stress is implemented here. Clearly this shows better result on yield stress, viscosity, and settling rate. Also permanent magnet generator (PMG) is designed and attached to a MR damper. For evaluating the self-powered MR damper's vibration mitigating capacity, an Engine Mount System using the MR damper is simulated. The ideal stiffness of the PMG for the Engine Mount System (EMS) is calculated by numerical study. The vibration mitigating performance of the EMS employing the self-powered & self sensing MR damper is theoretically calculated and evaluated in the frequency domain.

  5. Influence of magnetic fields on magneto-aerotaxis.

    Science.gov (United States)

    Bennet, Mathieu; McCarthy, Aongus; Fix, Dmitri; Edwards, Matthew R; Repp, Felix; Vach, Peter; Dunlop, John W C; Sitti, Metin; Buller, Gerald S; Klumpp, Stefan; Faivre, Damien

    2014-01-01

    The response of cells to changes in their physico-chemical micro-environment is essential to their survival. For example, bacterial magnetotaxis uses the Earth's magnetic field together with chemical sensing to help microorganisms move towards favoured habitats. The studies of such complex responses are lacking a method that permits the simultaneous mapping of the chemical environment and the response of the organisms, and the ability to generate a controlled physiological magnetic field. We have thus developed a multi-modal microscopy platform that fulfils these requirements. Using simultaneous fluorescence and high-speed imaging in conjunction with diffusion and aerotactic models, we characterized the magneto-aerotaxis of Magnetospirillum gryphiswaldense. We assessed the influence of the magnetic field (orientation; strength) on the formation and the dynamic of a micro-aerotactic band (size, dynamic, position). As previously described by models of magnetotaxis, the application of a magnetic field pointing towards the anoxic zone of an oxygen gradient results in an enhanced aerotaxis even down to Earth's magnetic field strength. We found that neither a ten-fold increase of the field strength nor a tilt of 45° resulted in a significant change of the aerotactic efficiency. However, when the field strength is zeroed or when the field angle is tilted to 90°, the magneto-aerotaxis efficiency is drastically reduced. The classical model of magneto-aerotaxis assumes a response proportional to the cosine of the angle difference between the directions of the oxygen gradient and that of the magnetic field. Our experimental evidence however shows that this behaviour is more complex than assumed in this model, thus opening up new avenues for research.

  6. 75 FR 11153 - Hydro Energy Technologies, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Science.gov (United States)

    2010-03-10

    ... Energy Regulatory Commission Hydro Energy Technologies, LLC; Notice of Preliminary Permit Application.... On November 6, 2009, Hydro Energy Technologies, LLC (Hydro Energy Technologies) filed an application...-hours. Hydro Energy Technologies: Anthony J. Marra Jr., President, Hydro Energy Technologies, LLC.,...

  7. Micro hydro-electric power stations

    Energy Technology Data Exchange (ETDEWEB)

    Monition, L.; Le Nir, M.; Roux, J.

    1984-01-01

    This book provides a discussion of all aspects of hydro-power exploitation using micro-power stations. It offers guidance to techniques for assessing the power available from a given stream, designing and building siteworks, selecting the appropriate turbine types for given conditions, and measuring and controlling environmental hazards associated with micro-hydro installations.

  8. Rheological properties of magneto-responsive copolymer gels

    NARCIS (Netherlands)

    An, H.

    2012-01-01

    New magneto rheological systems that respond mechanically to external homogeneous magnetic fields, namely, physically cross-linked magneto rheological (MR) gels, were synthesized and investigated. Various aspects of the rheological behavior were considered such as linear viscoelastic response for va

  9. Analysis of Magneto-Piezoelastic Anisotropic Materials

    Directory of Open Access Journals (Sweden)

    Alexander L. Kalamkarov

    2015-05-01

    Full Text Available The paper is concerned with the analysis of magneto-piezoelastic anistropic materials. Analytical modeling of magneto-piezoelastic materials is essential for the design and applications in the smart composite structures incorporating them as actuating and sensing constituents. It is shown that Green’s function method is applicable to time harmonic magneto-elastic-piezoelectricity problems using the boundary integral technique, and the exact analytical solutions are obtained. As an application, a two-dimensional static plane-strain problem is considered to investigate the effect of magnetic field on piezoelectric materials. The closed-form analytical solutions are obtained for a number of boundary conditions for all components of the magneto-piezoelectric field. As a special case, numerical results are presented for two-dimensional static magneto-electroelastic field of a piezoelectric solid subjected to a concentrated line load and an electric charge. The numerical solutions are obtained for three different piezoelectric materials and they demonstrate a substantial dependence of the stress and electric field distribution on the constitutive properties and magnetic flux.

  10. Magneto-optical Kramers-Kronig analysis.

    Science.gov (United States)

    Levallois, Julien; Nedoliuk, Ievgeniia O; Crassee, Iris; Kuzmenko, Alexey B

    2015-03-01

    We describe a simple magneto-optical experiment and introduce a magneto-optical Kramers-Kronig analysis (MOKKA) that together allow extracting the complex dielectric function for left- and right-handed circular polarizations in a broad range of frequencies without actually generating circularly polarized light. The experiment consists of measuring reflectivity and Kerr rotation, or alternatively transmission and Faraday rotation, at normal incidence using only standard broadband polarizers without retarders or quarter-wave plates. In a common case, where the magneto-optical rotation is small (below ∼0.2 rad), a fast measurement protocol can be realized, where the polarizers are fixed at 45(∘) with respect to each other. Apart from the time-effectiveness, the advantage of this protocol is that it can be implemented at ultra-high magnetic fields and in other situations, where an in-situ polarizer rotation is difficult. Overall, the proposed technique can be regarded as a magneto-optical generalization of the conventional Kramers-Kronig analysis of reflectivity on bulk samples and the Kramers-Kronig constrained variational analysis of more complex types of spectral data. We demonstrate the application of this method to the textbook semimetals bismuth and graphite and also use it to obtain handedness-resolved magneto-absorption spectra of graphene on SiC.

  11. Development of a Composite Suspension with a Coil and Hydro-Pneumatic Spring

    Institute of Scientific and Technical Information of China (English)

    YANG Bo; CHEN Si-zhong; WU Zhi-cheng; YANG Lin

    2008-01-01

    A new composite suspension is developed,where a coil spring and a hydro-pneumatic spring are used in order to improve the poor reliability of off-road vehicle with pure hydro-pneumatic suspension.According to road conditions,the two springs play different roles.The method for matching the composite suspension stiffness and distributing the load is proposed.The working pressure of hydro-pneumatic spring as well as the load and stiffness characteristics of composite suspension is compared with a pure hydro-pneumatic suspension.In addition,the ISO weighted vehicle body acceleration,suspension travel and relative dynamic load of the wheels between two kinds of suspension are analyzed with a quarter vehicle mode.The simulation result shows that the developed composite suspension is more suitable for off-road vehicle than the one hydro-pneumatic suspension,because the composite suspension can reduce the working pressure, improve the reliability and keep a similar ride cornfort with hydro-pneumatic suspension.

  12. Magneto-optical extinction trend inversion in ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Shulyma, S.I., E-mail: kiw_88@mail.ru; Tanygin, B.M., E-mail: b.m.tanygin@gmail.com; Kovalenko, V.F.; Petrychuk, M.V.

    2016-10-15

    Effects of pulse magnetic field on the optical transmission properties of thin ferrofluid (FF) layers were experimentally investigated. It was observed that, under an influence of an external uniform magnetic field, pulses applied to the samples surfaces in normal direction decrease the optical transmission with further returning it to its original state, even before the end of the field pulse. The dependencies of the observed effects on the magnetic pulse magnitude and the samples thickness were investigated. The experimental results are explained using FF columnar aggregates growth and lateral coalescence under influence of a magnetic field, leading to a light scattering type Rayleigh-to-Mie transition. Further evolution of this process comes to a geometrical optics scale and respective macroscopic observable opaque FF columnar aggregates emergence. These changes of optical transmission are non-monotonic during the magnetic field pulse duration with minimal value in the case of Mie scattering, which is known as a magneto-optical extinction trend inversion. The residual inversion was detected after the external magnetic field pulse falling edge. Using molecular dynamics simulation, we showed that a homogeneous external magnetic field is enough for the formation of columnar aggregates and their fusion. The results clarify the known Li theory (Li et al., 2004, 2007), implying an inhomogeneous field as a required prerequisite for the magneto-optical extinction trend inversion phenomenon. - Highlights: • Ferrofluid columnar aggregates have been observed in a homogeneous magnetic field. • Magneto-optical extinction trend inversion is related to the Mie light scattering. • Crucial role of columnar aggregates growth and lateral coalescence has been revealed. • Residual extinction trend inversion was observed after the field switch off.

  13. Magneto-optical trapping of diatomic molecules

    CERN Document Server

    Hummon, Matthew T; Stuhl, Benjamin K; Collopy, Alejandra L; Xia, Yong; Ye, Jun

    2012-01-01

    The development of the magneto-optical trap revolutionized the fields of atomic and quantum physics by providing a simple method for the rapid production of ultracold, trapped atoms. A similar technique for producing a diverse set of dense, ultracold diatomic molecular species will likewise transform the study of strongly interacting quantum systems, precision measurement, and physical chemistry. We demonstrate one- and two-dimensional transverse laser cooling and magneto-optical trapping of the polar molecule yttrium (II) oxide (YO). Using a quasicycling optical transition we observe transverse Doppler cooling of a YO molecular beam to a temperature of 5 mK, limited by interaction time. With the addition of an oscillating magnetic quadrupole field we demonstrate a transverse magneto-optical trap and achieve temperatures of 2 mK.

  14. Optimisation of Kinematics for Tracked Vehicle Hydro Gas Suspension System

    Directory of Open Access Journals (Sweden)

    S. Sridhar

    2006-11-01

    Full Text Available The modern-day armoured fighting vehicles (AFVs are basically tracked vehicles equippedwith hydro gas suspensions, in lieu of conventional mechanical suspensions like torsion barand coil spring bogie suspensions. The uniqueness of hydro gas suspension is that it offersa nonlinear spring rate, which is very much required for the cross-country moveability of atracked vehicle. The AFVs have to negotiate different cross-country terrains like sandy, rocky,riverbed, etc. and the road irregularities provide enumerable problems during dynamic loadingsto the design of hydro gas suspension system. Optimising various design parameters demandsinnovative design methodologies to achieve better ride performance. Hence, a comprehensivekinematic analysis is needed. In this study, a methodology has been derived to optimise thekinematics of the suspension by reorienting the cylinder axis and optimising the loadtransferringleverage factor so that the side thrust on the cylinder is minimised to a greaterextent. The optimisation ultimately increases the life of the high-pressure and high-temperaturepiston seals, resulting in enhanced system life for better dependability.

  15. Magneto-optical trap for polar molecules.

    Science.gov (United States)

    Stuhl, Benjamin K; Sawyer, Brian C; Wang, Dajun; Ye, Jun

    2008-12-12

    We propose a method for laser cooling and trapping a substantial class of polar molecules and, in particular, titanium (II) oxide (TiO). This method uses pulsed electric fields to nonadiabatically remix the ground-state magnetic sublevels of the molecule, allowing one to build a magneto-optical trap based on a quasicycling J' = J'' -1 transition. Monte Carlo simulations of this electrostatically remixed magneto-optical trap demonstrate the feasibility of cooling TiO to a temperature of 10 micrpK and trapping it with a radiation-pumping-limited lifetime on the order of 80 ms.

  16. Magneto-optical response in bimetallic metamaterials

    CERN Document Server

    Atmatzakis, Evangelos; Fedotov, Vassili; Vienne, Guillaume; Zheludev, Nikolay I

    2016-01-01

    We demonstrate resonant Faraday polarization rotation in plasmonic arrays of bimetallic nano-ring resonators consisting of Au and Ni sections. This metamaterial design allows to optimize the trade-off between the enhancement of magneto-optical effects and plasmonic dissipation. Although Ni sections correspond to as little as ~6% of the total surface of the metamaterial, the resulting magneto-optically induced polarization rotation is equal to that of a continuous film. Such bimetallic metamaterials can be used in compact magnetic sensors, active plasmonic components and integrated photonic circuits.

  17. Magneto--Coriolis waves in a spherical Couette flow experiment

    CERN Document Server

    Schmitt, Denys; La Rizza, Patrick; Nataf, Henri-Claude

    2016-01-01

    The dynamics of fluctuations in a fast rotating spherical Couette flow experiment in the presence of a strong dipolar magnetic field is investigated in detail, through a thorough analysis of the experimental data as well as a numerical study. Fluctuations within the conducting fluid (liquid sodium) are characterized by the presence of several oscillation modes, identified as magneto-Coriolis (MC) modes, with definite symmetry and azimuthal number. A numerical simulation provides eigensolutions which exhibit oscillation frequencies and magnetic signature comparable to the observation. The main characteristics of these hydromagnetic modes is that the magnetic contribution has a fundamental influence on the dynamical properties through the Lorentz forces, although its importance remains weak in an energetical point of view. Another specificity is that the Lorentz forces are confined near the inner sphere where the dipolar magnetic field is the strongest, while the Coriolis forces are concentrated in the outer fl...

  18. Reversible pumped hydro - benefits and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Torbjoern K.; Walseth, Eve C.

    2010-07-01

    Full text: The Norwegian hydro power system is dominated with high head turbines, Pelton and Francis with high capacity in the reservoirs. Originally they were built for secure energy supply. In the system there are also reversible pump turbine (RPT) plants where in times with spare energy, made it possible to pump water from the lower reservoir to the higher. Again the idea was to secure energy supply, which meant pumping in early autumn to fill the reservoirs for winter. In the recent years, a more active use of the RPT plants has been actualized. The free market made price difference between night and day interesting, hence a more frequent pumping was desirable. In the coming years, new-renewable energy sources will utterly enhance a more active use of the RPT plants. More active use of the RPT plants means more frequent starts and stops, both in pumping and in turbine mode. There are a lot of challenges in adopting a new strategy for operating the machinery. More effective start equipment is required. The machinery will be exposed to more frequent dynamic loads; the turbines will be run at part- and full load. The existing RPT plants are connected to huge reservoirs. That means the RPTs are not only for short sighted power regulations, as many RPT-plants in Europe, but are also capable for a substantial energy production. In Norway, the nature is very suitable for RPT plants, both in connection with existing power plants, were reservoirs and conduits are already established, and standing alone with a minimum of energy production. RPTs are, as a design, a compromise between effective generating and stable as well as effective pumping. Stable pumping often results in very steep flow-speed characteristics when operating as a turbine. When dealing with hydraulic transients these characteristics cause a higher change in flow and torque leading to instability during start-up and possible off-design operation point. The instability slows down the synchronization

  19. Magneto-optical extinction trend inversion in ferrofluids

    Science.gov (United States)

    Shulyma, S. I.; Tanygin, B. M.; Kovalenko, V. F.; Petrychuk, M. V.

    2016-10-01

    Effects of pulse magnetic field on the optical transmission properties of thin ferrofluid (FF) layers were experimentally investigated. It was observed that, under an influence of an external uniform magnetic field, pulses applied to the samples surfaces in normal direction decrease the optical transmission with further returning it to its original state, even before the end of the field pulse. The dependencies of the observed effects on the magnetic pulse magnitude and the samples thickness were investigated. The experimental results are explained using FF columnar aggregates growth and lateral coalescence under influence of a magnetic field, leading to a light scattering type Rayleigh-to-Mie transition. Further evolution of this process comes to a geometrical optics scale and respective macroscopic observable opaque FF columnar aggregates emergence. These changes of optical transmission are non-monotonic during the magnetic field pulse duration with minimal value in the case of Mie scattering, which is known as a magneto-optical extinction trend inversion. The residual inversion was detected after the external magnetic field pulse falling edge. Using molecular dynamics simulation, we showed that a homogeneous external magnetic field is enough for the formation of columnar aggregates and their fusion. The results clarify the known Li theory (Li et al., 2004, 2007), implying an inhomogeneous field as a required prerequisite for the magneto-optical extinction trend inversion phenomenon.

  20. A magneto rheological hybrid damper for railway vehicles suspensions

    Directory of Open Access Journals (Sweden)

    Gheorghe GHITA

    2012-09-01

    Full Text Available High speed railway vehicles features a specific lateral oscillation resulting from the coupled lateral displacement and yaw of the wheelset which leads to a sinusoid movement of the wheelset along the track, transferred to the entire vehicle. The amplitude of this oscillation is strongly dependant on vehicle’s velocity. Over a certain value, namely the critical speed, the instability phenomenon so-called hunting occurs. To raise the vehicle’s critical speed different designs of the suspension all leading to a much stiffer vehicle can be envisaged. Different simulations prove that a stiffer central suspension will decrease the passenger’s comfort in terms of lateral accelerations of the carboy. The authors propose a semi-active magneto rheological suspension to improve the vehicle’s comfort at high speeds. The suspension has as executive elements hybrid magneto rheological dampers operating under sequential control strategy type balance logic. Using an original mathematical model for the lateral dynamics of the vehicle the responses of the system with passive and semi-active suspensions are simulated. It is shown that the semi-active suspension can improve the vehicle performances.

  1. Biotin determination in food supplements by an electrochemical magneto biosensor.

    Science.gov (United States)

    Kergaravat, Silvina V; Gómez, Gabriel A; Fabiano, Silvia N; Laube Chávez, Tamara I; Pividori, María I; Hernández, Silvia R

    2012-08-15

    An electrochemical magneto biosensor for the rapid determination of biotin in food samples is reported. The affinity reaction was performed on streptavidin-modified magnetic microbeads as a solid support in a direct competitive format. The biotinylated horseradish peroxidase enzyme (biotin-HRP) competes with free biotin in the sample for the binding sites of streptavidin on the magnetic microbeads. The modified magnetic beads were then easily captured by a magneto graphite-epoxy composite electrode and the electrochemical signal was based on the enzymatic activity of the HRP enzyme under the addition of H(2)O(2) as the substrate and o-phenilendiamine as cosubstrate. The response was electrochemically detected by square wave voltammetry. The limit of detection was 8.4×10(-8) mol L(--1) of biotin (20 μg L(--1)) with a dynamic range from 0.94 to 2.4×10(-7) mol L(--1). Biotin-fortified commercial dietary supplement and infant formula samples were evaluated obtaining good performances in the results. Total time of analysis was 40 min per 20 assays.

  2. China expreses interest in philippine hydro

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    MEMBERS OF A CHINESE trade mission which visited the Philippines in December 2000 have said they are prepared to invest up to US$ 19M in the Philippines' energy sector, and are particularly interested in hydro power projects.

  3. The bottom line on hydro development

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, I.M.

    2000-08-01

    The financial investment behind some of India's current hydro projects is summarised. The three institutions financing the Indian hydro sector are: Power Finance Corporation (PFC), Rural Electrification Corporation (REC) and the Indian Renewable Energy Development Agency (IREDA). The terms of reference of each of the organisations, together with the role of the State Bank of India, have recently been rationalised (by the Federal Ministry of Power) and they are discussed. Both the federal and state governments offer the hydro industry support in the form of equity and soft loans. The scope for private participation and equity (available since 1991) are discussed. Although financial consultants have worked at making easier the financing of hydro in India, they have achieved only mixed results.

  4. Great Smoky Mountains National Park Hydro Plus

    Data.gov (United States)

    National Park Service, Department of the Interior — Park Hydro Plus is a value-added attribution of data produced by Great Smoky Mountains National Park and published by the USGS NHD. Not to be confused with the USGS...

  5. WaterHydro_WBD12VT

    Data.gov (United States)

    Vermont Center for Geographic Information — WaterHydro_WBD12VT was developed by NRCS. The boundaries on consistent with Vermont's Hydrography Dataset (VHD). This data set is a digital hydrologic unit boundary...

  6. Increasing wind energy penetration level using pumped hydro storage in island micro-grid system

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Sheikh Mominul [Memorial Univ. of Newfoundland, St. John' s, NL (Canada). Dept. of Engineering

    2012-07-01

    Ramea is a small island in southern Newfoundland. Since 2004, it has a wind-diesel hybrid power system to provide power for approximately 600 inhabitants. In this paper, wind speed data, load data, and sizing of pumped hydro system at Ramea, Newfoundland are presented. The dynamic model of wind turbine, pumped hydro system, and diesel generator are included in this paper. The dynamic model is simulated in SIMULINK/MATLAB to determine the system voltage and frequency variation and also to visualize different power outputs. Sizing of pumped hydro system indicates that a 150-kW pumped hydro storage system can be installed in Ramea to increase the renewable energy fraction to 37% which will reduce non-renewable fuel consumption on this island. Also, it is found that a pumped hydro energy storage system for Ramea is a much better choice than a hydrogen energy storage system. Such a system will have a higher overall efficiency and could be maintained using local technical expertise, therefore, a more appropriate technology for Ramea. (orig.)

  7. Comparison of the magneto-Peltier and magneto-Seebeck effects in magnetic tunnel junctions

    Science.gov (United States)

    Shan, J.; Dejene, F. K.; Leutenantsmeyer, J. C.; Flipse, J.; Münzenberg, M.; van Wees, B. J.

    2015-07-01

    Understanding heat generation and transport processes in a magnetic tunnel junction (MTJ) is a significant step towards improving its application in current memory devices. Recent work has experimentally demonstrated the magneto-Seebeck effect in MTJs, where the Seebeck coefficient of the junction varies as the magnetic configuration changes from a parallel (P) to an antiparallel (AP) configuration. Here we report a study on its reciprocal effect, the magneto-Peltier effect, where the heat flow carried by the tunneling electrons is altered by changing the magnetic configuration of the MTJ. The magneto-Peltier signal that reflects the change in the temperature difference across the junction between the P and AP configurations scales linearly with the applied current in the small bias but is greatly enhanced in the large-bias regime, due to higher-order Joule heating mechanisms. By carefully extracting the linear response which reflects the magneto-Peltier effect, and comparing it with the magneto-Seebeck measurements performed on the same device, we observe results consistent with Onsager reciprocity. We estimate a magneto-Peltier coefficient of 13.4 mV in the linear regime using a three-dimensional thermoelectric model. Our result opens up the possibility of programmable thermoelectric devices based on the Peltier effect in MTJs.

  8. Enhancement of the transverse magneto-optical Kerr effect via resonant tunneling in trilayers containing magneto-optical metals

    Science.gov (United States)

    Girón-Sedas, J. A.; Mejía-Salazar, J. R.; Moncada-Villa, E.; Porras-Montenegro, N.

    2016-07-01

    We propose a way to enhance the transverse magneto-optical Kerr effect, by the excitation of resonant tunneling modes, in subwavelength trilayer structures featuring a dielectric slab sandwiched between two magneto-optical metallic layers. Depending on the magneto-optical layer widths, the proposed system may exhibit an extraordinary transverse magneto-optical Kerr effect, which makes it very attractive for the design and engineering of thin-film magneto-optical-based devices for future photonic circuits or fiber optical-communication systems.

  9. Magneto-elastic interactions in terbium

    DEFF Research Database (Denmark)

    Jensen, J.

    1971-01-01

    Making use of the Hamiltonian for linear magneto-elastic coupling which has been proposed by Callen and Callen, expressions are deduced for changes in the velocity of acoustic waves in a terbium crystal, due to ferromagnetic ordering and the application of an external magnetic field...

  10. 78 FR 56224 - Hydro Nelson, Ltd.; Hydro-WM, LLC; Notice of Transfer of Exemption

    Science.gov (United States)

    2013-09-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hydro Nelson, Ltd.; Hydro-WM, LLC; Notice of Transfer of Exemption 1. By... in Nelson County, Virginia. The transfer of an exemption does not require Commission approval. \\1\\...

  11. 78 FR 2985 - Moretown Hydro Energy Company; Ampersand Moretown Hydro, LLC; Notice of Application for Transfer...

    Science.gov (United States)

    2013-01-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Moretown Hydro Energy Company; Ampersand Moretown Hydro, LLC; Notice of Application for Transfer of License, and Soliciting Comments and Motions To Intervene On September 25,...

  12. A comparison of the aquatic impacts of large hydro and small hydro projects

    Science.gov (United States)

    Taylor, Lara A.

    The expansion of small hydro development in British Columbia has raised concerns surrounding the effects of these projects, and the provincial government's decision to proceed with Site C has brought attention to the impacts of large hydro. Together, these decisions highlight that there are impacts associated with all energy development. My study examines the aquatic effects of large and small hydro projects using two case study sites: Site C and the Upper Harrison Water Power Project. I first determine the aquatic effects of each of the case study sites. Next, I use existing literature and benefits transfer to determine the monetary value of these effects. My results suggest that, with mitigation, small hydro projects have less of an effect on the environment than a large hydro project per unit of electricity. I also describe the implications of my study in the context of current British Columbia energy policy. Keywords: hydropower; aquatic effects. Subject Terms: environmental impact assessment; benefits transfer.

  13. Analysis, Predictive Modeling and Hoisted Object Impact Control in Hydro-cylinder Stage- Switching

    OpenAIRE

    S. V. Kobyzev; V. V. Lomakin

    2016-01-01

    The paper considers a problem of dynamic impact of hoisting mechanisms, which are based on the multistage hydro-cylinders, on the hoisted object. Hydro-cylinders have high specific characteristics, but there are also some drawbacks. One of them is an impact at the beginning and at the end of hoist and in switching the stages. And in case of switching the stages under certain conditions the impact in nature can be a high impact impulse. The paper explores the impacts at the beginning of hoist ...

  14. A Novel Frequency Restoring Strategy of Hydro-PV Hybrid Microgrid

    DEFF Research Database (Denmark)

    Wei, Feng; Kai, Sun; Guan, Yajuan

    2014-01-01

    The conventional PV systems based on the voltage inverters only inject dispatched power to the utility grid when they work at a grid-connected mode in the hydro-PV hybrid microgrid. Due to the droop method employed for load sharing between generators, as well as the enormous inertia of system....... The existence of frequency steady-state error and the slow active power/frequency dynamic response are inevitable. Therefore, a novel frequency restoring strategy for the hydro-PV hybrid microgrid based on the improved hierarchical control of PV systems is proposed in this paper. The output active power of PV...

  15. Sensor applications of soft magnetic materials based on magneto-impedance, magneto-elastic resonance and magneto-electricity.

    Science.gov (United States)

    García-Arribas, Alfredo; Gutiérrez, Jon; Kurlyandskaya, Galina V; Barandiarán, José M; Svalov, Andrey; Fernández, Eduardo; Lasheras, Andoni; de Cos, David; Bravo-Imaz, Iñaki

    2014-04-25

    The outstanding properties of selected soft magnetic materials make them successful candidates for building high performance sensors. In this paper we present our recent work regarding different sensing technologies based on the coupling of the magnetic properties of soft magnetic materials with their electric or elastic properties. In first place we report the influence on the magneto-impedance response of the thickness of Permalloy films in multilayer-sandwiched structures. An impedance change of 270% was found in the best conditions upon the application of magnetic field, with a low field sensitivity of 140%/Oe. Second, the magneto-elastic resonance of amorphous ribbons is used to demonstrate the possibility of sensitively measuring the viscosity of fluids, aimed to develop an on-line and real-time sensor capable of assessing the state of degradation of lubricant oils in machinery. A novel analysis method is shown to sensitively reveal the changes of the damping parameter of the magnetoelastic oscillations at the resonance as a function of the oil viscosity. Finally, the properties and performance of magneto-electric laminated composites of amorphous magnetic ribbons and piezoelectric polymer films are investigated, demonstrating magnetic field detection capabilities below 2.7 nT.

  16. Sensor Applications of Soft Magnetic Materials Based on Magneto-Impedance, Magneto-Elastic Resonance and Magneto-Electricity

    Directory of Open Access Journals (Sweden)

    Alfredo García-Arribas

    2014-04-01

    Full Text Available The outstanding properties of selected soft magnetic materials make them successful candidates for building high performance sensors. In this paper we present our recent work regarding different sensing technologies based on the coupling of the magnetic properties of soft magnetic materials with their electric or elastic properties. In first place we report the influence on the magneto-impedance response of the thickness of Permalloy films in multilayer-sandwiched structures. An impedance change of 270% was found in the best conditions upon the application of magnetic field, with a low field sensitivity of 140%/Oe. Second, the magneto-elastic resonance of amorphous ribbons is used to demonstrate the possibility of sensitively measuring the viscosity of fluids, aimed to develop an on-line and real-time sensor capable of assessing the state of degradation of lubricant oils in machinery. A novel analysis method is shown to sensitively reveal the changes of the damping parameter of the magnetoelastic oscillations at the resonance as a function of the oil viscosity. Finally, the properties and performance of magneto-electric laminated composites of amorphous magnetic ribbons and piezoelectric polymer films are investigated, demonstrating magnetic field detection capabilities below 2.7 nT.

  17. Load frequency stabilization of four area hydro thermal system using Superconducting Magnetic Energy Storage system

    Directory of Open Access Journals (Sweden)

    A.Ruby meena

    2014-07-01

    Full Text Available Automatic generation control in electric power system design is a major concern nowadays due to its rising size, varying structure, integration of renewable-energy sources and distributed generators to meet the growing demand. In this paper, automatic generation control of an interconnected four area hydro thermal system examined. Each area equipped with reheat turbine for thermal system and hydro turbine with electric governor for hydro system. Load frequency stabilization gained by including Superconducting Magnetic Energy Storage system (SMES in all areas. A comparative analysis made between Proportional and Integral (PI controller with Fuzzy Logic controller with and without including SMES in the four area power system. The designed Fuzzy Logic Controller can generate best dynamic performance for step load perturbations given in all areas. The system simulation realized by using MATLAB software.

  18. On the ill/well-posedness and nonlinear instability of the magneto-geostrophic equations

    CERN Document Server

    Friedlander, Susan

    2011-01-01

    We consider an active scalar equation that is motivated by a model for magneto-geostrophic dynamics and the geodynamo. We prove that the non-diffusive equation is ill-posed in the sense of Hadamard in Sobolev spaces. In contrast, the critically diffusive equation is well-posed. In this case we give an example of a steady state that is nonlinearly unstable, and hence produces a dynamo effect in the sense of an exponentially growing magnetic field.

  19. Domain wall magneto-Seebeck effect

    Science.gov (United States)

    Krzysteczko, Patryk; Hu, Xiukun; Liebing, Niklas; Sievers, Sibylle; Schumacher, Hans W.

    2015-10-01

    The interplay between charge, spin, and heat currents in magnetic nanostructures subjected to a temperature gradient has led to a variety of novel effects and promising applications studied in the fast-growing field of spin caloritronics. Here, we explore the magnetothermoelectrical properties of an individual magnetic domain wall in a permalloy nanowire. In thermal gradients of the order of few K /μ m along the long wire axis, we find a clear magneto-Seebeck signature due to the presence of a single domain wall. The observed domain wall magneto-Seebeck effect can be explained by the magnetization-dependent Seebeck coefficient of permalloy in combination with the local spin configuration of the domain wall.

  20. Image correction in magneto-optical microscopy

    DEFF Research Database (Denmark)

    Paturi, P.; Larsen, B.H.; Jacobsen, B.A.

    2003-01-01

    An image-processing procedure that assures correct determination of the magnetic field distribution of magneto-optical images is presented. The method remedies image faults resulting from sources that are proportional to the incident light intensity, such as different types of defects in the indi......An image-processing procedure that assures correct determination of the magnetic field distribution of magneto-optical images is presented. The method remedies image faults resulting from sources that are proportional to the incident light intensity, such as different types of defects...... in the indicator film and unevenness of light, as well as additive signals from detector bias, external light sources, etc. When properly corrected a better measurement of the local magnetic field can be made, even in the case of heavily damaged films. For superconductors the magnetic field distributions may...

  1. Magneto-optic studies of magnetic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gehring, Gillian A., E-mail: g.gehring@shef.ac.uk [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Alshammari, Marzook S.; Score, David S.; Neal, James R.; Mokhtari, Abbas; Fox, A. Mark [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)

    2012-10-15

    A brief review of the use of magneto-optic methods to study magnetic oxides is given. A simple method to obtain the magnetic circular dichroism (MCD) of a thin film on a transparent substrate is described. The method takes full account of multiple reflections in the film and substrate. Examples of the magneto-optic spectra of Co-doped ZnO, Fe{sub 3}O{sub 4}, and GdMnO{sub 3} are given. The Maxwell-Garnett method is used to describe the effects of metallic cobalt inclusions in Co:ZnO samples, and the change of the MCD spectra of Fe{sub 3}O{sub 4} at the Verwey temperature is discussed. Data showing different MCD signals at different energies is presented for GdMnO{sub 3}.

  2. Hydro-forming of sheet metal pairs for the production of hollow bodies; Etude du procede d'hydroformage de flans doubles pour la production de corps creux

    Energy Technology Data Exchange (ETDEWEB)

    Vahl, M.; Hein, P. [Erlangen-Nuernberg Univ., Erlangen (Germany); Bobbert, S. [Daimler Chrysler Aerospace Airbus GmbH, Bremen (Germany)

    2000-10-01

    The hydro-forming technology is well-known since several years and undergoes an extremely dynamic development in automotive applications, especially in Germany and the United States. The hydro-forming of sheet metal pairs is still at a pre-industrial stage. This publication presents the process and draws attention to some particular results of research work. Principal working directions for investigations, regarding the transfer of the hydro-forming process for sheet metal pairs to industry are mentioned. (authors)

  3. Domain wall magneto-Seebeck effect

    OpenAIRE

    Krzysteczko, Patryk; Hu, Xiukun; Liebing, Niklas; Sievers, Sibylle; Schumacher, Hans W.

    2014-01-01

    The interplay between charge, spin, and heat currents in magnetic nano systems subjected to a temperature gradient has lead to a variety of novel effects and promising applications studied in the fast-growing field of spincaloritronics. Here we explore the magnetothermoelectrical properties of an individual magnetic domain wall in a permalloy nanowire. In thermal gradients of the order of few Kelvin per micrometer along the long wire axis, we find a clear magneto-Seebeck signature due to the ...

  4. Giant Magneto-Impedance and its Applications

    CERN Document Server

    Tannous, C

    2002-01-01

    The status of Giant Magneto-Impedance effect is reviewed in Wires, Ribbons and Multilayered Soft Ferromagnetic Thin Films. After establishing the theoretical framework for the description of the effect, and the constraints any material should have in order to show the effect, experimental work in Wires, Ribbons and Multilayered Thin Films is described. Existing and potential applications of the effect in Electronics and Sensing are highlighted.

  5. Dependence of loading time on control parameters in a standard vapour-loaded magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi-Chi; Wu Ji-Zhou; Li Yu-Qing; Ma Jie; Wang Li-Rong; Zhao Yan-Ting; Xiao Lian-Tuan; Jia Suo-Tang

    2011-01-01

    Loading time is one of the most important dynamic characteristics of a magneto-optical trap.In this paper,we primarily report on a detailed experimental study of the effects of some magneto-optical trap control parameters on loading time,including the background vacuum pressure,the magnetic field gradient,and the intensities of trapping and repumping lasers.We compare the results with previous theoretical and experimental results,and give qualitative analysis.These experimental investigations offer some useful guidelines to control the loading time of magneto-optical traps.The controllable loading time achieved is helpful to enhance the signal-to-noise ratio of photoassociation spectroscopy,which is remarkably improved from 7 to 28.6.

  6. Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

    Science.gov (United States)

    Wu, Chun-Hsien; Sokolov, Konstantin

    2014-01-01

    Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture and detection of circulating tumor cells (CTCs), and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting. PMID:25177973

  7. Homogenization in micro-magneto-mechanics

    Science.gov (United States)

    Sridhar, A.; Keip, M.-A.; Miehe, C.

    2016-07-01

    Ferromagnetic materials are characterized by a heterogeneous micro-structure that can be altered by external magnetic and mechanical stimuli. The understanding and the description of the micro-structure evolution is of particular importance for the design and the analysis of smart materials with magneto-mechanical coupling. The macroscopic response of the material results from complex magneto-mechanical interactions occurring on smaller length scales, which are driven by magnetization reorientation and associated magnetic domain wall motions. The aim of this work is to directly base the description of the macroscopic magneto-mechanical material behavior on the micro-magnetic domain evolution. This will be realized by the incorporation of a ferromagnetic phase-field formulation into a macroscopic Boltzmann continuum by the use of computational homogenization. The transition conditions between the two scales are obtained via rigorous exploitation of rate-type and incremental variational principles, which incorporate an extended version of the classical Hill-Mandel macro-homogeneity condition covering the phase field on the micro-scale. An efficient two-scale computational scenario is developed based on an operator splitting scheme that includes a predictor for the magnetization on the micro-scale. Two- and three-dimensional numerical simulations demonstrate the performance of the method. They investigate micro-magnetic domain evolution driven by macroscopic fields as well as the associated overall hysteretic response of ferromagnetic solids.

  8. Alexela ostab Hydro Texaco tanklaketi / Gert D. Hankewitz

    Index Scriptorium Estoniae

    Hankewitz, Gert D.

    2006-01-01

    Kütusefirma Alexela Oil teatas, et ostab tanklaketi Hydro Texaco kõik Balti riikide tanklad. Diagramm: Alexela ja Hydro Texaco majandusnäitajad. Vt. samas: Statoili juht: ühinemine turul muutusi ei too

  9. Alexela ostab Hydro Texaco tanklaketi / Gert D. Hankewitz

    Index Scriptorium Estoniae

    Hankewitz, Gert D.

    2006-01-01

    Kütusefirma Alexela Oil teatas, et ostab tanklaketi Hydro Texaco kõik Balti riikide tanklad. Diagramm: Alexela ja Hydro Texaco majandusnäitajad. Vt. samas: Statoili juht: ühinemine turul muutusi ei too

  10. Lac Courte Oreilles Hydro Dam Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Jason [Lac Courte Oreilles, Hayward, WI (United States); Meyers, Amy [Kiser Hydro, LLC, Norway, MI (United States)

    2014-12-31

    The main objective of this project was to investigate upgrading the existing hydro power generating system at the Winter Dam. The tribe would like to produce more energy and receive a fair market power purchase agreement so the dam is no longer a drain on our budget but a contributor to our economy. We contracted Kiser Hydro, LLC Engineering for this project and received an engineering report that includes options for producing more energy with cost effective upgrades to the existing turbines. Included in this project was a negotiation of energy price sales negotiations.

  11. Wind / hydro complementary seasonal regimes in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Amarante, O.A.C. do [CAMARGO SCHUBERT Engenharia Eolica, Curitiba PR (Brazil); Schultz, D.J. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Bittencourt, R.M. [CHESF - Companhia Hidro Eletrica do Sao Francisco, Recife PE (Brazil); Rocha, N.A. [PROMON Engenharia Ltda., Rio de Janeiro, RJ (Brazil)

    2001-08-01

    In the last decades, wind power generation has proven its suitability to the Gigawatt scale, necessary to an effective contribution to electric systems. This paper demonstrates, from existing data, the wind / hydro seasonal complementarity in the relevant areas of Brazil, and discusses its possible effect on the feasibility of seasonal stabilization of the energy supply in the Brazilian interconnected grid, taking advantage of the country's large natural resources available. Case studies for the southern/southeastern and the northeastern regions of Brazil are presented. A brief analysis is included regarding the geographic location of the interconnected grid, main hydro power plants, and estimated promising wind farm areas in Brazil. (orig.)

  12. Hydro-Jet technology in urologic surgery.

    Science.gov (United States)

    Shekarriz, Bijan

    2005-05-01

    Hydro-Jet technology utilizes an extremely thin, high-pressure stream of water. This technology has been routinely used in industry as a cutting tool for different materials such as metal, ceramic, wood and glass. Recently, Hydro-Jet technology has been used for dissection and resection during open and laparoscopic surgical procedures. A high-pressure jet of water allows selective dissection and isolation of vital structures such as blood vessels and nerves. This has resulted in improved dissection and decreased complication rate in recent experimental and clinical studies. This technology has been successfully applied during open and laparoscopic partial nephrectomy, cholecystecomy and retroperitoneal lymphadenectomy.

  13. Market Power in Mixed Hydro-Thermal Electric Systems

    OpenAIRE

    M. Soledad Arellano

    2004-01-01

    This paper shows that, unlike what has been found in other papers, a hydro reservoir is an effective tool to exercise market power. Its appealing as a tool is enhanced by the fact that there is no need to constrain total hydro production - a practice too easy to detect -; it suffices to distort the intertemporal allocation of hydro production over time. A hydro-producer may increase his profits by exploiting differences in price elasticity of demand across periods, allocating too little suppl...

  14. Modeling and experimental verification of frequency-, amplitude-, and magneto-dependent viscoelasticity of magnetorheological elastomers

    Science.gov (United States)

    Xin, Fu-Long; Bai, Xian-Xu; Qian, Li-Jun

    2016-10-01

    Magnetorheological elastomers (MREs), a smart composite, exhibit dual characteristics of both MR materials and particle reinforced composites, i.e., the viscoelasticity of MREs depends on external magnetic field as well as strain amplitude and excitation frequency. In this article, the principle of a frequency-, amplitude-, and magneto-dependent linear dynamic viscoelastic model for isotropic MREs is proposed and investigated. The viscoelasticity of MREs is divided into frequency- and amplitude-dependent mechanical viscoelasticity and frequency-, amplitude-, and magneto-dependent magnetic viscoelasticity. Based on the microstructures of ferrous particles and matrix, the relationships between mechanical shear modulus corresponding to the mechanical viscoelasticity and strain amplitude and excitation frequency are obtained. The relationships between magnetic shear modulus corresponding to the magnetic viscoelasticity with strain amplitude, excitation frequency, and further external magnetic field are derived using the magneto-elastic theory. The influence of magnetic saturation on the MR effect is also considered. The dynamic characteristics of a fabricated isotropic MRE sample under different strain amplitudes, excitation frequencies and external magnetic fields are tested. The parameters of the proposed model are identified with the experimental data and the theoretical expressions of shear storage modulus and shear loss modulus of the MRE sample are obtained. In the light of the theoretical expressions, the loss factors of the MRE sample under different loading conditions are analyzed and compared with the test results to evaluate the effectiveness of the proposed model.

  15. 75 FR 71104 - Lock Hydro Friends Fund XXXV; FFP Missouri 7, LLC; Dashields Hydro, LLC; Notice of Competing...

    Science.gov (United States)

    2010-11-22

    ...; Project No. 13779-000] Lock Hydro Friends Fund XXXV; FFP Missouri 7, LLC; Dashields Hydro, LLC; Notice of... Intervene November 15, 2010. On May 18, 2010, Lock Hydro Friends Fund XXXV, FFP Missouri 7, LLC, and... (877) 556-6566 x711. FFP Missouri 7, LLC's project (Project No. 13756-000) would consist of: (1)...

  16. 77 FR 10740 - Lock+ Hydro Friends Fund VIII, FFP Project 92, LLC, Riverbank Hydro No. 24, LLC; Notice...

    Science.gov (United States)

    2012-02-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Lock+ Hydro Friends Fund VIII, FFP Project 92, LLC, Riverbank Hydro No. 24.... 14262-000, FFP Project 92, LLC for Project No. 14276-000, and Riverbank Hydro No. 24, LLC for Project...

  17. Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

    Science.gov (United States)

    Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C

    2015-02-01

    We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

  18. Magneto-electric effect for multiferroic thin film by Monte Carlo simulation

    Science.gov (United States)

    Wang, Zidong; Grimson, Malcolm J.

    2015-06-01

    Magneto-electric (ME) effect in a multiferroic heterostructure film, i.e., a coupled ferromagnetic-ferroelectric thin film, has been investigated through the use of the Metropolis algorithm in Monte Carlo simulations. A classical Heisenberg model describes the energy stored in the ferromagnetic (FM) film, and we use a pseudo-spin model with a transverse Ising Hamiltonian to characterise the energy of electric dipoles in the ferroelectric (FE) film. The purpose of this article is to demonstrate the dynamic response of polarisation is driven by an external magnetic field, when there is a linear magneto-electric coupling at the interface between the ferromagnetic and ferroelectric components. Contribution to the topical issue "Advanced Electromagnetics Symposium (AES 2014) - Elected submissions", edited by Adel Razek

  19. Hydro reservoir handling in Norway before and after deregulation

    Energy Technology Data Exchange (ETDEWEB)

    Wolfgang, Ove; Haugstad, Arne; Mo, Birger; Gjelsvik, Anders [SINTEF Energy Research, 7465 Trondheim (Norway); Wangensteen, Ivar; Doorman, Gerard [NTNU, Department of Electric Power Engineering, 7491 Trondheim (Norway)

    2009-10-15

    The Norwegian Energy Act that came into force in 1991 deregulated the electricity market and removed the former obligation power companies had to supply electricity to the geographical area they were responsible for. Hence producers can supply electricity on the basis of profitability. In 2007 the Energy Act was evaluated by the Government. As a part of this, a study concerning hydro reservoir handling before and after deregulation was carried out by SINTEF. Public statistics show that average hydro reservoir levels measured in per cent of reservoir capacity have been reduced after 1990. We have used the power-market model EMPS (EFI's Multi-area Power-market Simulator) to analyze if this reduction can be explained by natural variation in climatic variables or by structural changes that have occurred after 1990. Simulation results show that the reduced reservoir levels cannot be explained by natural variation in climatic variables. Structural changes such as increased transmission capacities can, however, explain some of the reduction. Our study does not indicate that the present reservoir handling gives reservoir levels that are too low. In this paper we also describe the stochastic dynamic optimization problem for long-term hydropower scheduling, and we explain how this problem actually is solved by the EMPS model. (author)

  20. Small hydro policy and potential in Spain

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Spain has 662 small hydro installations, as registered in the “Speciaf Regimen” of 31 December 1999, with 1,271,573 kW of instaffed power producing the equivalent of the electricity consumed by 1.1 million families, avoiding emissions of 2.6 million tonnes of CO2 per year and substituting 250,000 toe.

  1. Contract for new Scottish hydro station

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A£4M (US$6M) Contract has been awarded to Miller Civil Engineering Services for the construction of Scottish and Southern Energy's new 3MW hydro power station on the river Cuileig, near Ullapoot in Scotland, The plant will be the pow, er company's first new hydroelectric station since the 1960s. Construction is set to take 12 months, beginning in mid November,

  2. Pico-hydro for affordable village power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-15

    This project developed and disseminated 'off-the-shelf' hydro generator units of up to 5kW that are: directly affordable by villagers in remote communities of developing counties; financially viable through fuel savings and income generation; and suitable for local manufacture and use in adverse conditions. Work was undertaken in Nepal, Colombia and Peru. (author)

  3. Micro hydro demo in the Philippines

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Philippine department of Energy (DOE) has signed a memorandum of agreement with the Japanese government for a P33.SM (US$0.67M) demonstration project. The 65kW micro hydro power system will benefit about 200 households in Leyte.

  4. Research on the low-voltage ride-through capability of wind synchronous generator with hydro-dynamically controlled gearbox%液力变矩型同步风力发电机低电压穿越性能分析

    Institute of Scientific and Technical Information of China (English)

    王军伟

    2016-01-01

    液力变矩型同步风力发电机组是国内近期投运的一种新机型,它的核心技术是应用WinDrive液力变矩器进行变矩调速,实现风机可变输入转速的恒速输出,为发电机同步并网提供稳定的输入转速。同步发电机的励磁系统配套自动电压调节器进行励磁控制,有效地解决了传统风机低电压穿越能力差、无功输出能力不足的问题。针对2.0MW液力变矩型同步风力发电机的运行特点,研究其工作原理及控制策略,建立机组主要组件的数学模型,结合实际参数进行模拟仿真,分析了电网短路故障时机组低电压穿越的动态响应能力。%The wind synchronous generator with hydro-dynamically controlled gearbox is a new type of machine applied to wind turbine in China in recent years, and the heart of its technology is to apply WinDrive variable-speed hydraulic torque converter for the purpose of speed adjustment. It can convert the variable input speed into the constant speed output, and can provide a stable input speed for generator synchronous grid connection. Especially, the synchronous generator works together with AVR and has well excitation control function, and it effectively solves the problems that the low voltage ride through capability of the traditional turbine is poor and the reactive power output capability is insufficient. Based on the operation characteristics of 2.0MW wind synchronous generator with hydro-dynamically controlled gearbox by studying its working principles and control strategies, the mathematical model of the main components of the unit is established, the simulation experiments combined with the actual parameters are presented, and the low-voltage ride-through dynamic-response capability of the system at the very moment of grid short-circuit fault is also studied.

  5. Comparison of the magneto-Peltier and magneto-Seebeck effects in magnetic tunnel junctions

    NARCIS (Netherlands)

    Shan, J.; Dejene, F. K.; Leutenantsmeyer, J. C.; Flipse, J.; Munzenberg, M.; van Wees, B. J.

    2015-01-01

    Understanding heat generation and transport processes in a magnetic tunnel junction (MTJ) is a significant step towards improving its application in current memory devices. Recent work has experimentally demonstrated the magneto-Seebeck effect in MTJs, where the Seebeck coefficient of the junction v

  6. Identification of vibration loads on hydro generator by using hybrid genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    Shouju Li; Yingxi Liu

    2006-01-01

    Vibration dynamic characteristics have been a major issue in the modeling and mechanical analysis of large hydro generators.An algorithm is developed for identifying vibration dynamic characteristics by means of hybrid genetic algorithm.From the measured dynamic responses of a hydro generator,an appropriate estimation algorithm is needed to identify the loading parameters,including the main frequencies and amplitudes of vibrating forces.In order to identify parameters in an efficient and robust manner,an optimization method is proposed that combines genetic algorithm with simulated annealing and elitist strategy.The hybrid genetic algorithm is then used to tackle an ill-posed problem of parameter identification.In which the effectiveness of the proposed optimization method is confirmed by its comparison with actual observation data.

  7. Magneto-rheological defects and failures: A review

    Science.gov (United States)

    Wahid, SA; Ismail, I.; Aid, S.; Rahim, MSA

    2016-02-01

    Magneto-rheological fluid is the colloidal suspension of micron sized magnetic particles in a carrier fluid where defects and failures occur at many circumstances. This paper presents a review on defects and failures of magneto-rheological fluid in engineering applications. The most significant defect is hard cake which developed due to re-dispersion difficulties of remnant particles magnetization, leaving the magneto-rheological fluid ineffective. Clumping effect on the other hand is a separation of carrier fluid from the magnetic particles when magneto-rheological fluid is being exposed to higher magnetic field for an extended period of time. As clumping occurred, it leads to Fluid Particle Separation (FPS) which is believed altering the strength distribution of magneto-rheological fluid and therefore reducing the squeezing force. Another significant failure is magnetic particles oxidation of the magneto-rheological fluid. This paper also will discuss on stability problems which is the most challenged issue in magneto-rheological fluid technology. With the comprehensive review in this paper, researcher can design materials of magneto-rheological fluid for better properties.

  8. Nonlinear Synergistic Emergence and Predictability in Complex Systems: Theory and Hydro-Climatic Applications

    Science.gov (United States)

    Perdigão, Rui A. P.; Hall, Julia; Pires, Carlos A. L.; Blöschl, Günter

    2017-04-01

    Classical and stochastic dynamical system theories assume structural coherence and dynamic recurrence with invariants of motion that are not necessarily so. These are grounded on the unproven assumption of universality in the dynamic laws derived from statistical kinematic evaluation of non-representative empirical records. As a consequence, the associated formulations revolve around a restrictive set of configurations and intermittencies e.g. in an ergodic setting, beyond which any predictability is essentially elusive. Moreover, dynamical systems are fundamentally framed around dynamic codependence among intervening processes, i.e. entail essentially redundant interactions such as couplings and feedbacks. That precludes synergistic cooperation among processes that, whilst independent from each other, jointly produce emerging dynamic behaviour not present in any of the intervening parties. In order to overcome these fundamental limitations, we introduce a broad class of non-recursive dynamical systems that formulate dynamic emergence of unprecedented states in a fundamental synergistic manner, with fundamental principles in mind. The overall theory enables innovations to be predicted from the internal system dynamics before any a priori information is provided about the associated dynamical properties. The theory is then illustrated to anticipate, from non-emergent records, the spatiotemporal emergence of multiscale hyper chaotic regimes, critical transitions and structural coevolutionary changes in synthetic and real-world complex systems. Example applications are provided within the hydro-climatic context, formulating and dynamically forecasting evolving hydro-climatic distributions, including the emergence of extreme precipitation and flooding in a structurally changing hydro-climate system. Validation is then conducted with a posteriori verification of the simulated dynamics against observational records. Agreement between simulations and observations is

  9. Magneto-Plasmonic Nanoantennas: Basics and Applications (Review)

    CERN Document Server

    Maksymov, Ivan S

    2016-01-01

    Plasmonic nanoantennas is a hot and rapidly expanding research field. Here we overview basic operating principles and applications of novel magneto-plasmonic nanoantennas, which are made of ferromagnetic metals and driven not only by light, but also by external magnetic fields. We demonstrate that magneto-plasmonic nanoantennas enhance the magneto-optical effects, which introduces additional degrees of freedom in the control of light at the nano-scale. This property is used in conceptually new devices such as magneto-plasmonic rulers, ultra-sensitive biosensors, one-way subwavelength waveguides and extraordinary optical transmission structures, as well as in novel biomedical imaging modalities. We also point out that in certain cases 'non-optical' ferromagnetic nanostructures may operate as magneto-plasmonic nanoantennas. This undesigned extra functionality capitalises on established optical characterisation techniques of magnetic nanomaterials and it may be useful for the integration of nanophotonics and nan...

  10. Accurate, Meshless Methods for Magneto-Hydrodynamics

    CERN Document Server

    Hopkins, Philip F

    2016-01-01

    Recently, we developed a pair of meshless finite-volume Lagrangian methods for hydrodynamics: the 'meshless finite mass' (MFM) and 'meshless finite volume' (MFV) methods. These capture advantages of both smoothed-particle hydrodynamics (SPH) and adaptive mesh-refinement (AMR) schemes. Here, we extend these to include ideal magneto-hydrodynamics (MHD). The MHD equations are second-order consistent and conservative. We augment these with a divergence-cleaning scheme, which maintains div*B~0 to high accuracy. We implement these in the code GIZMO, together with a state-of-the-art implementation of SPH MHD. In every one of a large suite of test problems, the new methods are competitive with moving-mesh and AMR schemes using constrained transport (CT) to ensure div*B=0. They are able to correctly capture the growth and structure of the magneto-rotational instability (MRI), MHD turbulence, and the launching of magnetic jets, in some cases converging more rapidly than AMR codes. Compared to SPH, the MFM/MFV methods e...

  11. PERTURBATION ANALYSIS FOR MAGNETO-PLASTIC INSTABILITY OF FERROMAGNETIC BEAM-PLATES WITH GEOMETRIC IMPERFECTION

    Institute of Scientific and Technical Information of China (English)

    ZhouYouhe; GaoYuanwen; ZhengXiaojing

    2004-01-01

    The magneto-plastic instability of a ferromagnetic beam-type plate with simple supports and small initial imperfection is analytically investigated in this paper for that the plastic deformation of the plate with a linear-strain hardening relation is considered when the plate is located in a strong uniformly distributed magnetic field. After the distribution of magnetic fields related to the deflected configuration of plate is imaginably divided into two parts, i.e.,one is related to the flat plate and the other dependent on the perturbation of magnetic fields for which the plate configuration changes from the flat into the deformed state, the perturbation technique is employed to analyze the distribution of the perturbation magnetic fields in and out-of the magnetic medium of the ferromagnetic structure in a transverse magnetic field, which leads to some analytical formulae/solutions for the magnetic fields and the resulting magnetic force exerted on the plate. Based on them, the magneto-plastic buckling and snapping of the plate in a transverse magnetic field is discussed, and the critical magnetic field is analytically formulated in terms of the parameters of geometry and material of the plate employed by solving the governing equation of the magneto-plastic plate in the applied magnetic field. Further, the sensitivity of the initial imperfection on the magneto-plastic instability, expressed by an amplification function, is obtained by solving the dynamic equation of deflection of the plate after the inertial force in the transverse direction is taken into account. The results obtained show that the critical magnetic field is sensitive to the plastic characteristic, e.g., hardening coefficient, and the instability mode and deflection of the plate are dependent on the geometrical imperfection as well.

  12. Surface magneto plasmons and their applications in the infrared frequencies

    Directory of Open Access Journals (Sweden)

    Hu Bin

    2015-11-01

    Full Text Available Due to their promising properties, surface magneto plasmons have attracted great interests in the field of plasmonics recently. Apart from flexible modulation of the plasmonic properties by an external magnetic field, surface magneto plasmons also promise nonreciprocal effect and multi-bands of propagation, which can be applied into the design of integrated plasmonic devices for biosensing and telecommunication applications. In the visible frequencies, because it demands extremely strong magnetic fields for the manipulation of metallic plasmonic materials, nano-devices consisting of metals and magnetic materials based on surface magneto plasmon are difficult to be realized due to the challenges in device fabrication and high losses. In the infrared frequencies, highly-doped semiconductors can replace metals, owning to the lower incident wave frequencies and lower plasma frequencies. The required magnetic field is also low, which makes the tunable devices based on surface magneto plasmons more practically to be realized. Furthermore, a promising 2D material-graphene shows great potential in infrared magnetic plasmonics. In this paper, we review the magneto plasmonics in the infrared frequencies with a focus on device designs and applications. We investigate surface magneto plasmons propagating in different structures, including plane surface structures and slot waveguides. Based on the fundamental investigation and theoretical studies, we illustrate various magneto plasmonic micro/nano devices in the infrared, such as tunable waveguides, filters, and beam-splitters. Novel plasmonic devices such as one-way waveguides and broad-band waveguides are also introduced.

  13. Magneto-acoustic imaging by continuous-wave excitation.

    Science.gov (United States)

    Shunqi, Zhang; Zhou, Xiaoqing; Tao, Yin; Zhipeng, Liu

    2016-07-01

    The electrical characteristics of tissue yield valuable information for early diagnosis of pathological changes. Magneto-acoustic imaging is a functional approach for imaging of electrical conductivity. This study proposes a continuous-wave magneto-acoustic imaging method. A kHz-range continuous signal with an amplitude range of several volts is used to excite the magneto-acoustic signal and improve the signal-to-noise ratio. The magneto-acoustic signal amplitude and phase are measured to locate the acoustic source via lock-in technology. An optimisation algorithm incorporating nonlinear equations is used to reconstruct the magneto-acoustic source distribution based on the measured amplitude and phase at various frequencies. Validation simulations and experiments were performed in pork samples. The experimental and simulation results agreed well. While the excitation current was reduced to 10 mA, the acoustic signal magnitude increased up to 10(-7) Pa. Experimental reconstruction of the pork tissue showed that the image resolution reached mm levels when the excitation signal was in the kHz range. The signal-to-noise ratio of the detected magneto-acoustic signal was improved by more than 25 dB at 5 kHz when compared to classical 1 MHz pulse excitation. The results reported here will aid further research into magneto-acoustic generation mechanisms and internal tissue conductivity imaging.

  14. Minoan and Etruscan Hydro-Technologies

    OpenAIRE

    Pietro Laureano; Anastasia Zourou; Giovanni De Feo; Andreas N. Angelakis

    2013-01-01

    The aim of this study is to present water and wastewater technologies used during the Minoan (ca. 3200–1100 BC) and Etruscan (ca. 800–100 BC) civilizations. The basic technologies considered are: water harvesting and distribution systems, cisterns, groundwater and wells as well as drainage and sewerage systems. Minoan water collection and distribution systems primarily consisted of cisterns and pipes. The Etruscans’ hydro-technology also consisted of cisterns and pipes but was developed for u...

  15. Upgrading the dosimetry at Ontario Hydro

    Energy Technology Data Exchange (ETDEWEB)

    Hirning, C.R. [Ontario Hydro, Whitby, ON (Canada). Health Physics Dept.

    1996-12-01

    Ontario Hydro has embarked upon a major programme to replace and upgrade its external dosimetry systems. In two year`s time, the utility expects to have two state-of-the-art dosimetry systems in place: a new TLD dosimetry of legal record that was designed nearly 30 years ago; and an electronic dosimetry system which could eventually replace the TLD as the primary system. (Author).

  16. Upgrading hydro-electric generating facilities

    Energy Technology Data Exchange (ETDEWEB)

    Coulson, D.M.; Villalon, M.

    1987-11-01

    Approximately 1,720,000 kW of installed hydro-electric generating capacity is either owned directly by pulp and paper companies in Canada or is operated principally in their service. The 216 units involved were commissioned between 1902 and 1982. This paper suggests an approach to upgrading the generating units themselves as well as the related electrical and mechanical equipment and civil structures, giving approximate durations and costs. A complete system study is recommended. 2 refs., 2 figs., 3 tabs.

  17. Transverse Magneto-Optical Kerr Effect in Active Magneto-Plasmonic Structures

    CERN Document Server

    Borovkova, Olga; Belotelov, Vladimir

    2016-01-01

    We propose a novel method to enhance the transverse magneto-optical Kerr effect (TMOKE) in the magneto-plasmonic (MP) nanostructures by means of the active dielectric layer. We report the theoretical analysis of the magnetoplasmonic structure with a ferromagnetic dielectric doped with rear-earth ions (Nd3+) as the example of a gain layer. The enhancement takes place near the surface plasmon polariton (SPP) resonances of the nanostructures. The stimulated emission of the dopants in the field of SPP wave partially compensates its losses. It is shown that due to a decrease of SPP damping a Q-factor of the MP resonance increases and the TMOKE is increased in comparison with the passive nanostructure.

  18. Magneto-optic detection system with noise cancellation

    Science.gov (United States)

    Lewicki, G. W.; Guisinger, J. E. (Inventor)

    1973-01-01

    In a magneto-optic readout system, a polarized beam of light from a laser is subjected to the magneto-optical effect of a magnetic record medium, and then passed through an analyzer which resolves the beam into two orthogonal vector components so oriented that the two components are of equal amplitude when the angle of rotation due to the magneto-optic effect is zero. Separate photodetectors produce two output signals which are proportional to the amplitudes of the vector components. The two output signals are combined in a differential amplifier through separate logarithmic transfer circuits to produce an output signal proportional to the ratio of the two original detector signals.

  19. 2D Magneto-optical trapping of diatomic molecules.

    Science.gov (United States)

    Hummon, Matthew T; Yeo, Mark; Stuhl, Benjamin K; Collopy, Alejandra L; Xia, Yong; Ye, Jun

    2013-04-05

    We demonstrate one- and two-dimensional transverse laser cooling and magneto-optical trapping of the polar molecule yttrium (II) oxide (YO). In a 1D magneto-optical trap (MOT), we characterize the magneto-optical trapping force and decrease the transverse temperature by an order of magnitude, from 25 to 2 mK, limited by interaction time. In a 2D MOT, we enhance the intensity of the YO beam and reduce the transverse temperature in both transverse directions. The approach demonstrated here can be applied to many molecular species and can also be extended to 3D.

  20. Magneto-Optical Activity in High Index Dielectric Nanoantennas

    CERN Document Server

    de Sousa, N; Sáenz, J J; García-Martín, A

    2016-01-01

    The magneto-optical activity, namely the polarization conversion capabilities of high-index, non-absorbing, core-shell dielectric nanospheres is theoretically analyzed. We show that, in analogy with their plasmonic counterparts, the polarization conversion in resonant dielectric particles is linked to the amount of electromagnetic field probing the magneto-optical material in the system. However, in strong contrast with plasmon nanoparticles, due to the peculiar distribution of the internal fields in resonant dielectric spheres, the magneto-optical response is fully governed by the magnetic (dipolar and quadrupolar) resonances with little effect of the electric ones.

  1. Magneto-optical switch with amorphous silicon waveguides on magneto-optical garnet

    Science.gov (United States)

    Ishida, Eiichi; Miura, Kengo; Shoji, Yuya; Mizumoto, Tetsuya; Nishiyama, Nobuhiko; Arai, Shigehisa

    2016-08-01

    We fabricated a magneto-optical (MO) switch with a hydrogenated amorphous silicon waveguide on an MO garnet. The switch is composed of a 2 × 2 Mach-Zehnder interferometer (MZI). The switch state is controlled by an MO phase shift through a magnetic field generated by a current flowing in an electrode located on the MZI. The switching operation was successfully demonstrated with an extinction ratio of 11.7 dB at a wavelength of 1550 nm.

  2. On the connection between the magneto-elliptic and magneto-rotational instabilities

    CERN Document Server

    Mizerski, Krzysztof A

    2012-01-01

    It has been recently suggested that the magneto-rotational instability (MRI) is a limiting case of the magneto-elliptic instability (MEI). This limit is obtained for horizontal modes in the presence of rotation and an external vertical magnetic field, when the aspect ratio of the elliptic streamlines tends to infinite. In this paper we unveil the link between these previously unconnected mechanisms, explaining both the MEI and the MRI as different manifestations of the same Magneto-Elliptic-Rotational Instability (MERI). The growth rates are found and the influence of the magnetic and rotational effects is explained, in particular the effect of the magnetic field on the range of negative Rossby numbers at which the horizontal instability is excited. Furthermore, we show how the horizontal rotational MEI in the rotating shear flow limit links to the MRI by the use of the local shearing box model, typically used in the study of accretion discs. In such limit the growth rates of the two instability types coincid...

  3. An Overview of Power Topologies for Micro-hydro Turbines

    DEFF Research Database (Denmark)

    Nababan, Sabar; Muljadi, E.; Blaabjerg, Frede

    2012-01-01

    This paper is an overview of different power topologies of micro-hydro turbines. The size of micro-hydro turbine is typically under 100kW. Conventional topologies of micro-hydro power are stand-alone operation used in rural electrical network in developing countries. Recently, many of micro-hydro...... power generations are connected to the distribution network through power electronics (PE). This turbines are operated in variable frequency operation to improve efficiency of micro-hydro power generation, improve the power quality, and ride through capability of the generation. In this paper our...... discussion is limited to the distributed generation. Like many other renewable energy sources, the objectives of micro-hydro power generation are to reduce the use of fossil fuel, to improve the reliability of the distribution system (grid), and to reduce the transmission losses. The overview described...

  4. The Intermediate r-process in Core-collapse Supernovae Driven by the Magneto-rotational Instability

    Science.gov (United States)

    Nishimura, N.; Sawai, H.; Takiwaki, T.; Yamada, S.; Thielemann, F.-K.

    2017-02-01

    We investigated r-process nucleosynthesis in magneto-rotational supernovae, based on a new explosion mechanism induced by the magneto-rotational instability (MRI). A series of axisymmetric magneto-hydrodynamical simulations with detailed microphysics including neutrino heating is performed, numerically resolving the MRI. Neutrino-heating dominated explosions, enhanced by magnetic fields, showed mildly neutron-rich ejecta producing nuclei up to A∼ 130 (i.e., the weak r-process), while explosion models with stronger magnetic fields reproduce a solar-like r-process pattern. More commonly seen abundance patterns in our models are in between the weak and regular r-process, producing lighter and intermediate-mass nuclei. These intermediate r-processes exhibit a variety of abundance distributions, compatible with several abundance patterns in r-process-enhanced metal-poor stars. The amount of Eu ejecta ∼ {10}-5 {M}ȯ in magnetically driven jets agrees with predicted values in the chemical evolution of early galaxies. In contrast, neutrino-heating dominated explosions have a significant amount of Fe ({}56{{Ni}}) and Zn, comparable to regular supernovae and hypernovae, respectively. These results indicate magneto-rotational supernovae can produce a wide range of heavy nuclei from iron-group to r-process elements, depending on the explosion dynamics.

  5. StatoilHydro Seeks Business Development in China

    Institute of Scientific and Technical Information of China (English)

    Xu Ming

    2008-01-01

    @@ Established on October 1, 2007 with the merger of Norway's national oil company Statoil and the oil and gas operations of Hydro, StatoilHydro (SH) is now a giant enterprise with ambitions for global growth. Ole Johan Lydersen, president of StatoilHydro China, talked about his expectations for growth through powerful partnerships with its Chinese counterparts in a recent interview with news media

  6. Vibration analysis of a hydro generator for different operating regimes

    Science.gov (United States)

    Haţiegan, C.; Pădureanu, I.; Jurcu, M.; Nedeloni, M. D.; Hamat, C. O.; Chioncel, C. P.; Trocaru, S.; Vasile, O.; Bădescu, O.; Micliuc, D.; (Filip Nedeloni, L.; Băra, A.; (Barboni Haţiegan, L.

    2017-01-01

    Based on experimental measurements, this paper presents the vibration analysis of a hydro generator that equips a Kaplan hydraulic turbine of a Hydropower plant in Romania. This analysis means vibrations measurement to different operating regimes of the hydro generator respectively before installing it and into operation, namely putting off load mode (unexcited and excited) respectively putting on load mode. By comparing, through the experimental results obtained before and after the operation of hydro aggregates are observed vibrations improvements.

  7. Hydro-power in a competitive market; Hydro-Power im Wettbewerbsumfeld

    Energy Technology Data Exchange (ETDEWEB)

    Schroefelbauer, H. [VERBUND-Austrian Hydro Power AG, Wien (Austria)

    2005-07-01

    While energy demand continues to rise, European hydro-power is faced with ever more stringent legal provisions and environmental targets. At the same time, the transition from a monopoly situation to a liberalised electricity market has resulted in a shift in emphasis from macro-economic considerations to a business-mangement approach to hydro-power as the classic renewable energy source. Hence, for market operators hoping to position themselves favourable through the offer of new products, such as control and balancing energy, it is essential to recognise emerging technology and energy trends at an early point in time. However, fair competition requires a stable legal framework. (orig.)

  8. Magneto-Radar Hidden Metal Detector

    Energy Technology Data Exchange (ETDEWEB)

    McEwan, Thomas E. (Las Vegas, NV)

    2005-07-05

    A varying magnetic field excites slight vibrations in an object and a radar sensor detects the vibrations at a harmonic of the excitation frequency. The synergy of the magnetic excitation and radar detection provides increased detection range compared to conventional magnetic metal detectors. The radar rejects background clutter by responding only to reflecting objects that are vibrating at a harmonic excitation field, thereby significantly improving detection reliability. As an exemplary arrangement, an ultra-wideband micropower impulse radar (MIR) is capable of being employed to provide superior materials penetration while providing range information. The magneto-radar may be applied to pre-screening magnetic resonance imaging (MRI) patients, landmine detection and finding hidden treasures.

  9. Magneto-Optical Trap for Thulium Atoms

    CERN Document Server

    Sukachev, D; Chebakov, K; Akimov, A; Kanorsky, S; Kolachevsky, N; Sorokin, V

    2010-01-01

    Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to $7\\times10^{4}$ atoms at a temperature of 0.8(2) mK after deceleration in a 40 cm long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the MOT which varies between 0.3 -1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s$^{-1}$. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives a 30% increase for the lifetime and the number of atoms in the trap.

  10. Magneto-photonic phenomena at terahertz frequencies

    CERN Document Server

    Shalaby, Mostafa

    2014-01-01

    Magneto-terahertz phenomena are the main focus of the thesis. This work started as supporting research for the science of an X-ray laser (SwissFEL). X-ray lasers have recently drawn great attention as an unprecedented tool for scientific research on the ultrafast scale..... To answer this fundamental question, we performed original numerical simulations using a coupled Landau- Lifshitz-Gilbert Maxwell model. ... Those requirements were the motivations for the experiments performed in the second part of the thesis. To shape the terahertz pulses, .... Regarding the field intensities, we followed two approaches. The first deals with field enhancement in nanoslits arrays. We designed a subwavelength structure characterized by simultaneous high field enhancement and high transmission at terahertz frequencies to suit nonlinear sources. The second approach depended on up-scaling the generation from laser-induced plasma by increasing the pump wavelengths. Numerical calculations have also brought to our attention the ...

  11. Magneto-Optical Trapping of Holmium Atoms

    CERN Document Server

    Miao, J; Stratis, G; Saffman, M

    2014-01-01

    We demonstrate sub-Doppler laser cooling and magneto-optical trapping of the rare earth element Holmium. Atoms are loaded from an atomic beam source and captured in six-beam $\\sigma_+ - \\sigma_-$ molasses using a strong $J=15/2 \\leftrightarrow J=17/2$ cycling transition at $\\lambda=410.5~\\rm nm$. Due to the small difference in hyperfine splittings and Land\\'e $g$-factors in the lower and upper levels of the cooling transition the MOT is self-repumped without additional repump light, and deep sub-Doppler cooling is achieved with the magnetic trap turned on. We measure the leakage out of the cycling transition to metastable states and find a branching ratio $\\sim 10^{-5}$ which is adequate for state resolved measurements on hyperfine encoded qubits.

  12. Technology applications for Magneto Inertial Fusion

    Science.gov (United States)

    Intrator, T.; Weber, T.; Gao, K.; Yoo, C.; Klarenbeek, J.

    2012-10-01

    We describe several technology advances that we believe will be helpful for Magneto Inertial Fusion (MIF) experiments. We are developing plasma guns to improve the startup and flux trapping for magnetized plasma field reversed configuration (FRC) targets for MIF compression. This should aid initial pre ionization, freezing in of bias flux, line tie each end to the middle to retard toroidal rotation, and provide end shorting of radial electric fields. We are also developing a novel magnetic field diagnostic that uses a tiny section of Terbium doped optical fiber as a Faraday rotation medium. The optical path and hardware is inexpensive and simple, and has a small form factor that will fit inside a MagLIF capsule, and can be radation hardened. Low noise, optically coupled magnetic field measurements will be possible for vacuum MaGLIF shots.

  13. Magneto-optical imaging of exotic superconductors

    Science.gov (United States)

    van der Beek, C. J.; Losco, J.; Konczykowski, M.; Pari, P.; Shibauchi, T.; Shishido, H.; Matsuda, Y.

    2009-02-01

    We have constructed a novel compact cryostat for optical measurements at temperatures below 2 K. The desktop cryostat, small enough to be placed under the objective of a standard commercial polarized light microscope, functions in a single shot mode, with a five hour autonomy at 1.5 K. Central to its conception are four charcoal pumps for adsorption and desorption of He contained in a closed circuit, and novel thermal switches allowing for thermalization of the pumps and of the two 1 K pots. The latter are connected to the 1" diameter sample holder through braids. Sample access is immediate, through the simple removal of the optical windows. In this contribution, we shall present first results on magneto-optical imaging of flux penetration in the heavy-fermion superconductor CeCoIn5.

  14. Tailoring Giant Magneto-impedance Effect in Ultrasoft Ferromagnetic Microwires

    Science.gov (United States)

    Chaturvedi, A.; Ruiz, A.; Mukherjee, P.; Srikanth, H.; Phan, M. H.; Larin, V. S.

    2012-02-01

    Research on soft ferromagnetic microwires exhibiting giant magneto-impedance (GMI) effect, which is a large change of the ac impedance of a ferromagnetic conductor in a static magnetic field, for advanced magnetic sensor applications is an area of topical interest. In this study we show how the GMI effect and its field sensitivity are optimized in Co-B-Si-Mn microwires by varying the magnetic core to glass shell diameter ratio (d). The microwires have been fabricated by the glass-coated melt spinning method. The largest values of GMI (245%) and its field sensitivity 25%/Oe are achieved at f = 13MHz for the microwires with d = 0.86. The d dependence of the magneto-impedance has been analyzed based on those of the magneto-resistance and magneto-reactance. Our studies indicate that the microwires with optimized GMI response are attractive candidate materials for structural health self-monitoring and magnetic biosensing applications.

  15. Metallic magneto-electronic materials and its expectations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The basic characters, properties and possible applications of magneto-electronic materials with metal lic sandwich structure have been introduced. The expectation of its further development has been conjectured.

  16. Viscosity and Vorticity in Reduced Magneto-Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Ilon [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-12

    Magneto-hydrodynamics (MHD) critically relies on viscous forces in order for an accurate determination of the electric eld. For each charged particle species, the Braginskii viscous tensor for a magnetized plasma has the decomposition into matrices with special symmetries.

  17. Nonlinear surface magneto-plasmonics in Kretschmann multilayers

    CERN Document Server

    Razdolski, Ilya; Rasing, Theo; Makarov, Denys; Schmidt, Oliver G; Temnov, Vasily V

    2015-01-01

    The nonlinear magneto-plasmonics aims to utilize plasmonic excitations to control the mechanisms and taylor the efficiencies of the non-linear light frequency conversion at the nanoscale. We investigate the mechanisms of magnetic second harmonic generation in hybrid gold-cobalt-silver multilayer structures, which support propagating surface plasmon polaritons at both fundamental and second harmonic frequencies. Using magneto-optical spectroscopy in Kretschmann geometry, we show that the huge magneto-optical modulation of the second harmonic intensity is dominated by the excitation of surface plasmon polaritons at the second harmonic frequency, as shown by tuning the optical wavelength over the spectral region of strong plasmonic dispersion. Our proof-of-principle experiment highlights bright prospects of nonlinear magneto-plasmonics and contributes to the general understanding of the nonlinear optics of magnetic surfaces and interfaces.

  18. Magneto-elastic artificial neurons with extremely low energy dissipation

    Science.gov (United States)

    Biswas, Ayan K.; Al-Rashid, Md Mamun; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo

    2015-03-01

    We present a detailed analysis of artificial step transfer function neurons and binary weight synapses implemented with magneto-tunneling junctions whose soft layers are magnetostrictive nanomagnets switched with voltage generated mechanical strain. These devices are more energy-efficient than CMOS-based neurons or so-called spin neurons that are based on magnets switched with spin-polarized current. We studied their switching dynamics using stochastic Landau-Lifshitz-Gilbert simulations for two different geometries (elliptical and cylindrical) of the magnetostrictive nanomagnet. Our study revealed that while the step transition (firing) of the magnetic neuron is always very sharp at 0 K, the threshold is significantly broadened at room temperature, regardless of geometry and regardless of whether the magnet is switched with strain or spin-polarized current. While this could preclude some applications, the extreme energy-efficiency of these neurons makes them nearly ideal for use in certain types of neuromorphic computation. This work is supported by the NSF under grant ECCS-1124714 and CCF-1216614.

  19. Magneto centrifugal winds from accretion discs around black hole binaries

    CERN Document Server

    Chakravorty, S; Ferreira, J; Henri, G; Belmont, R; Clavel, M; Corbel, S; Rodriguez, J; Coriat, M; Drappeau, S; Malzac, J

    2016-01-01

    We want to test if self-similar magneto-hydrodynamic (MHD) accretion-ejection models can explain the observational results for accretion disk winds in BHBs. In our models, the density at the base of the outflow, from the accretion disk, is not a free parameter, but is determined by solving the full set of dynamical MHD equations without neglecting any physical term. Different MHD solutions were generated for different values of (a) the disk aspect ratio ($\\varepsilon$) and (b) the ejection efficiency ($p$). We generated two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. The cold MHD solutions are found to be inadequate to account for winds due to their low ejection efficiency. The warm solutions can have sufficiently high values of $p (\\gtrsim 0.1)$ which is required to explain the observed physical quantities in the wind. The heating (required at the disk surface for the warm solutions) could be due to the illumination which would b...

  20. Magneto-optical spectroscopy of (Ga,Mn)N epilayers

    Science.gov (United States)

    Marcet, S.; Ferrand, D.; Halley, D.; Kuroda, S.; Mariette, H.; Gheeraert, E.; Teran, F. J.; Sadowski, M. L.; Galera, R. M.; Cibert, J.

    2006-09-01

    We report on the magneto-optical spectroscopy and cathodoluminescence of a set of wurtzite (Ga,Mn)N epilayers with a low Mn content, grown by molecular-beam epitaxy. The sharpness of the absorption lines associated with the Mn3+ internal transitions allows a precise study of its Zeeman effect in both Faraday and Voigt configurations. We obtain a good agreement if we assume a dynamical Jahn-Teller effect in the 3d4 configuration of Mn, and we determine the parameters of the effective Hamiltonians describing the T25 and E5 levels, and those of the spin Hamiltonian in the ground spin multiplet, from which the magnetization of the isolated ion can be calculated. On layers grown on transparent substrates, transmission close to the band gap, and the associated magnetic circular dichroism, reveal the presence of the giant Zeeman effect resulting from exchange interactions between the Mn3+ ions and the carriers. The spin-hole interaction is found to be ferromagnetic.

  1. Magneto-mechanical actuation model for fin-based locomotion

    CERN Document Server

    Carbajal, Juan Pablo; 10.2495/DN100331

    2011-01-01

    In this paper, we report the results from the analysis of a numerical model used for the design of a magnetic linear actuator with applications to fin-based locomotion. Most of the current robotic fish generate bending motion using rotary motors which implies at least one mechanical conversion of the motion. We seek a solution that directly bends the fin and, at the same time, is able to exploit the magneto-mechanical properties of the fin material. This strong fin-actuator coupling blends the actuator and the body of the robot, allowing cross optimization of the system's elements. We study a simplified model of an elastic element, a spring-mass system representing a flexible fin, subjected to nonlinear forcing, emulating magnetic interaction. The dynamics of the system is studied under unforced and periodic forcing conditions. The analysis is focused on the limit cycles present in the system, which allows the periodic bending of the fin and the generation of thrust. The frequency, maximum amplitude and cente...

  2. Quantum magneto-optics of the graphite family

    Energy Technology Data Exchange (ETDEWEB)

    Falkovsky, L. A., E-mail: falk@itp.ac.ru [Landau Institute for Theoretical Physics (Russian Federation)

    2012-12-15

    The optical conductivity of graphene, bilayer graphene, and graphite in quantizing magnetic fields is studied. Both dynamical conductivities, longitudinal and Hall's, are evaluated analytically. The conductivity peaks are explained in terms of electron transitions. Correspondences between the transition frequencies and the magneto-optical features are established using the theoretical results. We show that trigonal warping can be considered within the perturbation theory for strong magnetic fields larger than 1 T. The semiclassical approach is applied for weak fields when the Fermi energy is much larger than the cyclotron frequency. The main optical transitions obey the selection rule with {Delta}n = 1 for the Landau number n, but the {Delta}n = 2 transitions due to the trigonal warping are also possible. The Faraday/Kerr rotation and light transmission/reflection in quantizing magnetic fields are calculated. Parameters of the Slonczewski-Weiss-McClure model are used in the fit taking the previous de Haas-van Alphen measurements into account and correcting some of them in the case of strong magnetic fields.

  3. State of the art of numerical simulation of magneto-hydro dynamics in the continuous casting process%连铸过程中电磁流体力学的数值模拟现状及发展趋势

    Institute of Scientific and Technical Information of China (English)

    刘和平

    2015-01-01

    对连铸过程中电磁流体力学的数值模拟的研究现状进行了综合评述.介绍了一种应用于连铸过程中的低频电磁流体力学数值模拟的新方法,并给出了其在圆坯旋转搅拌、CSP薄板坯电磁制动和板坯二冷辊式行波搅拌中的应用实例.该方法特点是分别建立电磁场模型和流场模型,并采用磁感应方程实现电磁场和流场模型之间的耦合.结果表明,目前的方法可较为准确地描述连铸过程中的电磁场分布和电磁流体力学特点,并能够对电磁搅拌参数和连铸工艺过程进行优化.最后,提出了连铸过程中电磁流体力学数值模拟技术的未来发展趋势.

  4. Bloch oscillations of quasispin polaritons in a magneto-optically controlled atomic ensemble

    CERN Document Server

    Jiang, Chang; Zhou, Lan

    2012-01-01

    We consider the propagation of a quantized polarized light in a magneto-optically manipulated atomic ensemble with a tripod configuration. Polariton formalism is applied when the medium is subjected to a washboard magnetic field under electromagnetically induced transparency. The dark-state polariton with multiple components is achieved. We analyze quantum dynamics of the dark-state polariton by some experiment data from rubidium D1-line. It is found that one component propagates freely, however the wavepacket trajectory of the other component performs Bloch oscillations.

  5. The last great hydro power frontier[Hydro power projects in Southeast Asia

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.

    2001-10-01

    A short article discusses hydro power projects in Myanmar in Southeast Asia. A table lists projects planned and projects under construction in Mandalay, Magwe, Sagaing, Shan, Kayin, Mon, Bago, Thanintharyl and Rakhine. Humanitarianism is said to be Japan's motive for establishing a presence there; the implications of the developments with respect to human rights and the military are mentioned.

  6. Condition indexing of embankment dams : case studies from Manitoba Hydro and Hydro-Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Halayko, K. [Manitoba Hydro, Winnipeg, MB (Canada); Gervais, R. [Hydro-Quebec, Montreal, PQ (Canada); Chouinard, L. [McGill Univ., Montreal, PQ (Canada)

    2003-07-01

    Large inventories of earth embankment dams that require regular maintenance and repairs are managed by both Manitoba Hydro and Hydro-Quebec. A rational procedure was developed for the allocation of limited maintenance and repairs funds while still optimizing dam safety objectives. This paper describes a procedure based on the adaptation of the Condition Indexing procedure initially developed by the United States Army Corps of Engineers, which allows for the allocation of maintenance and repair funds to the components deemed the most important and in the worst condition. The application of the Condition Index procedure was illustrated by examining a sample of different embankment dams operated by Manitoba Hydro and Hydro-Quebec. The primary failure modes are correctly identified by the Condition Index procedure, and it prioritizes the most relevant repair and maintenance activities. This paper describes, and the presents the results of, studies on an embankment dam on limestone foundation, an embankment dam on a clay foundation, and an embankment dam on alluvial soils. 5 refs., 17 tabs.

  7. Hydro-abrasive erosion: Problems and solutions

    Science.gov (United States)

    Winkler, K.

    2014-03-01

    The number of hydro power plants with hydro-abrasive erosion is increasing worldwide. An overall approach is needed to minimize the impact of this phenomenon. Already at the start of the planning phase an evaluation should be done to quantify the erosion and the impact on the operation. For this, the influencing parameters and their impact on the erosion have to be known. The necessary information for the evaluation comprises among others the future design, the particle parameters of the water, which will pass the turbine, and the power plant owner's framework for the future operation like availability or maximum allowable efficiency loss, before an overhaul needs to be done. Based on this evaluation of the erosion, an optimised solution can then be found, by analysing all measures in relation to investments, energy production and maintenance costs as decision parameters. Often a more erosion-resistant design, instead of choosing the turbine design with the highest efficiency, will lead to higher revenue. The paper will discuss the influencing parameters on hydro-abrasive erosion and the problems to acquire this information. There are different optimisation possibilities, which will be shown in different case studies. One key aspect to reduce the erosion and prolong the operation time of the components is to coat all relevant parts. But it is very important that this decision is taken early in the design stage, as the design has to be adapted to the requirements of the coating process. The quality of coatings and their impact on the operation will be discussed in detail in the paper as due to the non-availability of standards many questions arise in projects.

  8. DEVELOPMENT OF TEST PROTOCOLS FOR THE ANALYSIS OF MAGNETO-RHEOLOGICAL PROPERTIES OF FIELD-RESPONSIVE BITUMINOUS BINDERS

    Directory of Open Access Journals (Sweden)

    Ezio Santagata

    2014-01-01

    Full Text Available Magneto-rheological fluids are materials that exhibit a significant change in their rheological properties in the presence of a magnetic field. Because of such a field-dependent behavior, they can act as smart materials in applications in which changeable performances are desired. In road pavement engineering, the use of bitumen-based magneto-rheological fluids may open innovative scenarios related to the construction of smart pavement sections and to the investigation of damage mechanisms in binders and mixtures. The research work presented in this study explored magneto-rheological properties of several field-responsive bituminous binders obtained from two different base bitumens combined with multi-wall carbon nanotubes and powder iron. The experimental program included oscillatory shear loading tests at different temperatures, performed in the strain controlled mode by means of a dynamic shear rheometer equipped with a magneto-rheological device. The investigation was carried out with the specific goal of identifying critical issues which should be taken into account in materials preparation, testing procedures and data analysis. Undesired overheating of specimens during testing was identified and taken into account for a correct interpretation of experimental data. Thus, while the field-sensitivity of carbon nanotubes was found to be negligible as a result of the magnetic shielding action of bitumen, it was shown that powder iron can significantly affect the magneto-rheological properties of bituminous binders when employed in sufficiently high amounts. Moreover, obtained results indicated that selection of base bitumen is a key factor in designing bituminous-based smart materials. Practical implications which derive from the study are mainly relative to the fine-tuning of laboratory characterization procedures which should necessarily overcome current limitations in temperature regulation and magnetic field generation. Experimental data

  9. Standardized CSR and climate performance: why is Shell willing, but Hydro reluctant?; Shell; Hydro

    Energy Technology Data Exchange (ETDEWEB)

    Boasson, Elin Lerum; Wettestad, Joergen

    2007-06-15

    This report aims to contribute to the ongoing discussion concerning whether CSR merely serves to streamline company rhetoric or also has an influence on actual efforts. We discuss the tangible effects of CSR instruments on the climate-related rules and performances of the two different oil companies Hydro and Shell. First we explore whether similar CSR instruments lead to similar climate-related rules and practices in the two companies. Both Hydro and Shell adhere to the Global Compact (GC), the Global Reporting Initiative (GRI), the Carbon Disclosure Project (CDP) and the Global Gas Flaring Reduction Public-Private Partnership (GGFR). The report concludes that the GC has not rendered any tangible effects in either of the companies. Concerning the other instruments, Hydro has only followed the instrument requirements that fit their initial approach, and refrained from all deviating requirements. Shell has been more malleable, but we have noted few effects on the actual emissions and business portfolio resulting from the instrument adherence. Second, we assess how the differing results of the similar CSR portfolio may be explained. The reluctant attitude of the leaders in Hydro and the strong CSR motivation of Shell's executives result in significant differences. Hydro executives are able to constrain the effects of the instrument adherence. With Shell we note the opposite pattern: Its leaders promoted the instruments to be translated into internal rules, but a general lack of hierarchical structures hinders them from governing the conduct of various sub-organisations. The very diversity of the Shell culture helps to explain why the efforts of its executives have resulted in limited impact. The strength of the Hydro culture makes the corporation resistant to the instruments. Moreover, Hydro is strikingly shielded by virtue of its strong position in Norway. In contrast, Shell is more strongly affected by the global field of petroleum and the global field of CSR

  10. Extravertebral gas and fluid effusions associated with vertebral collapse containing a vacuum cleft possibly result from a pumping phenomenon: a new evidence of the dynamic hydro-pneumatical nature of the so-called vacuum phenomenon.

    Science.gov (United States)

    Coulier, B

    2013-01-01

    We report two very unusual observations in which gas and fluid effusions were transiently and unexpectedly found in the extravertebral spaces of patients presenting with painful necrotic vertebral collapse containing a vacuum cleft. We hypothesize that gas and/or fluid which progressively may replace vacuum in vertebral compression fractures could be secondarily pumped through extravertebral and retroperitoneal spaces. Although being rare, these observations may represent a potential missing link in the imaging snapshots of the cyclic and dynamic vacuum phenomenon.

  11. Development of a new module for the measurement of the magneto-electric direct and converse effects based on an alternating current susceptometer

    Science.gov (United States)

    Bueno-Baques, D.; Hurtado-Lopez, G.; Corral-Flores, V.; Gomez, S.; Diley, N. R.; Glushchenko, A.

    2014-08-01

    A new module for the measurement of magneto-electric properties was developed as an add-on for a magnetic AC susceptibility option of a Physical Properties Measurement System (PPMS). The module is capable of recording direct dynamic and static converse magneto-electric effect, i.e., the change in electric polarization due to the application of a small AC magnetic field with a DC magnetic field bias, or the change in the magnetic moment induced by an applied electric field. The versatile module setup supports both measurements in a sequential order without the need of removing or repositioning the sample. Furthermore, AC and DC magnetic susceptibilities can be recorded while performing direct and inverse magneto-electric measurements, respectively, which adds outstanding capabilities to the existing instrument while saving time and resources. Measurements are fully automated and integrated in the PPMS Multivu software platform. Magneto-electric behavior of a BaTiO3/CoFe2O4 and BaTiO3/NiFe2O4 magneto-electric composites, and a Pb(Fe0.5Nb0.5)O3 single phase compound were recorded as test measurements.

  12. Thermoelectric Responsive Shape Memory Graphene/Hydro-Epoxy Composites for Actuators

    Directory of Open Access Journals (Sweden)

    Yongkun Wang

    2016-08-01

    Full Text Available A series of thermoelectric responsive shape memory hydro-epoxy (H-EP composites filled with different contents of graphene were developed and characterized. Compared with traditional actuation materials, these novel shape memory composites exhibit attractive properties, such as light weight, large deformation, good processability and high response speed, making them good candidates for actuator materials. The effect of graphene content on the shape memory composites was studied in terms of mechanical, dynamic mechanical analysis (DMA, electrical properties, and thermoelectric responsive shape memory test. The results show that when graphene content was 2 wt %, the bend strength of the composite improved by about 47% with a storage modulus larger than other composites. The shape recovery ratio of the composites was about 100%, and the shape recovery speed increased with the increment of graphene content, applied voltage, and temperature. Due to the excellent actuation performance, the graphene/hydro-epoxy composite has potential applications in the actuator in the future.

  13. Boosting the assessment of Ungauged small hydro sites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Small hydro sites located in mountain environments are often on ungauged streams. A software package called the integrated Method for Power (IMP 4.0) was designed to assist inexperienced, potential developers of smaff hydro sites in situations where the cost of professionaf engineering advice would be prohibitive.

  14. The HYDROS mission: requirements and baseline system design

    Science.gov (United States)

    Njoku, Eni; Spencer, Michael; McDonald, Kyle; Smith, Joel; Houser, Paul; Doiron, Terence; ONeill, Peggy; Girard, Ralph; Entekhabi, Dara

    2004-01-01

    The HYDROS mission is under development by NASA as part of its Earth System Science Pathfinder program. HYDROS is designed to provide global maps of the Earth's soil moisture and freeze/thaw state every 2-3 days, for weather and climate prediction, water and carbon cycle studies, natural hazards monitoring, and national security applications.

  15. Integrated monopoly costs Hydro a sale in Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-06-01

    As a result of a recent ruling of the Federal Energy Regulatory Commission (FERC) of the USA made under the reciprocity provisions of 1977, Detroit Edison refused to wheel Ontario Hydro`s power to Ohio as of April 1, 1997. The new FERC ruling overturned earlier rules which had allowed Ontario Hydro to sell electricity to US utility customers who did not have direct transmission links with Ontario. This refusal by Detroit Edison, based on the FERC ruling, puts in danger all of Ontario Hydro`s sales to the US which require intermediate wheeling. The utility claims that the rules could reduce the corporation`s export to the US by as much as a $100 million in gross revenue this year, and up to $250 million in 1998. Ontario Hydro has petitioned the US courts to squash the FERC order. FERC maintains that the order resulted from Ontario Hydro`s adamant refusal to allow other electricity suppliers to sell into the province.

  16. Managing the risks of operating a hydro playground

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, G.D.; Blackburn, P.C. (Van Ness, Feldman Curtis, Washington, DC (United States))

    1992-04-01

    An integral part of most hydro projects is some recreational opportunity for the public. As a result, plant owners need to be aware of and manage their exposure to recreational liability. This article discusses liability and the measures that hydro plant owners can take to reduce their risk.

  17. When small is beautiful. Boom time for small hydro?

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, John

    2002-08-01

    Although small hydropower projects generally contribute a small proportion of most nations' electricity needs their importance often exceeds their size. The author, a freelance industrial journalist considers prospects for small hydro, how such schemes are benefiting communities throughout the world and why some countries are more successfully using small hydro than others. (Author)

  18. The Trans-African Hydro-Meteorological Observatory (TAHMO)

    NARCIS (Netherlands)

    Van de Giesen, N.C.; Hut, R.W.; Selker, J.

    2014-01-01

    In this opinion article, we present the Trans-African Hydro-Meteorological Observatory (TAHMO). The goal of TAHMO is to develop a dense network of hydro-meteorological measurement stations throughout sub-Saharan Africa. On average, there will be one station per 1000 km2. The stations will be cost-ef

  19. Mesoscopic hydro-thermodynamics of phonons

    Directory of Open Access Journals (Sweden)

    Aurea R. Vasconcellos

    2013-07-01

    Full Text Available A generalized Hydrodynamics, referred to as Mesoscopic Hydro-Thermodynamics, of phonons in semiconductors is presented. It involves the descriptions of the motion of the quasi-particle density and of the energy density. The hydrodynamic equations, which couple both types of movement via thermo-elastic processes, are derived starting with a generalized Peierls-Boltzmann kinetic equation obtained in the framework of a Non-Equilibrium Statistical Ensemble Formalism, providing such Mesoscopic Hydro-Thermodynamics. The case of a contraction in first order is worked out in detail. The associated Maxwell times are derived and discussed. The densities of quasi-particles and of energy are found to satisfy coupled Maxwell-Cattaneo-like (hyperbolic equations. The analysis of thermo-elastic effects is done and applied to investigate thermal distortion in silicon mirrors under incidence of high intensity X-ray pulses in FEL facilities. The derivation of a generalized Guyer-Krumhansl equation governing the flux of heat and the associated thermal conductivity coefficient is also presented.

  20. The Atlin Hydro Project : generation for generations

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, S. [Atlin Tlingit Development Corp., Atlin, BC (Canada)

    2010-07-01

    This presentation documented the step-by-step process by which the Atlin Hydro Project was developed. The Taku River Tlingit First Nation undertook the Atlin project as part of its vision for responsible resource management, sustainable economic development, and cultural revival. The Atlin Community Energy Plan involved an assessment of electricity demand, a 20-year demand projection, energy efficiency recommendations, and an assessment of power supply options such as wind towers, connection to the Yukon power grid, and hydro. The potential impact on fisheries, hydrology, wildlife habitat, roads and bridges, navigable waters and forests, existing rights, and First Nation archaeology were assessed, along with other factors such as hazards and flood control. A hydrology assessment of the Surprise-Pine Drainage Basin was undertaken, and stream-flow measurements were taken near the intake location on Pine Creek. The project comprises a discharge control structure and a fish ladder; an intake and weir on Pine Creek; a penstock pipeline from intake to powerhouse; a powerhouse with a 2.1 MW Pelton turbine generator and a switch yard; and a power line from the powerhouse to the interconnection with the existing grid. The impacts on fisheries, wildlife, and human movement are expected to be minimal. 28 figs., 3 tabs.

  1. Hydro-MRI in inflammatory bowel diseases: a comparison with colonoscopy and histopathology; Hydro-MRT bei entzuendlichen Darmerkrankungen - Eine koloskopisch-histologische Vergleichsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, K.; Reiter, S.; Kern, A. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Orth, T.; Wanitschke, R. [Mainz Univ. (Germany). Medizinische Klinik und Poliklinik

    2001-08-01

    Purpose: To compare hydro-MRI with colonoscopy and biopsy specimen regarding the assessment of inflammatory activity and the differentiation of inflammatory bowel diseases. Material and methods: After an oral bowel opacification using 1000 ml of a 2.5% mannitol solution and a rectal bowel opacification using 250-500 ml of a 0.9% saline solution, axial and coronal breath-hold sequences {+-}Gd-DTPA (HASTE-['half-Fourier acquisition single-shot turbo spin echo'] and dynamic FLASH-['fast low angle shot']) were acquired in 27 patients with inflammatory bowel disease. The enhancement of the bowel wall as well as morphological MRI findings were correlated with colonoscopy and biopsy specimens. By means of the MRI findings, Crohn's disease (CD) and ulcerative colitis (UC) should be differentiated. Results: In CD, a significant correlation between the contrast enhancement of the inflamed bowel wall ({delta} SI) and the endoscopic/histopathologic indices could be established (r=0.52; p=0.02 and r=0.72; p=0.001). In UC, no correlations between {delta} SI and the endoscopic/histopathologic indices could be found. The correct diagnosis of CD and UC by MRI findings was possible in 22/27 patients (81%). Conclusion: Hydro-MRI with dynamic studies is suitable for the assessment of disease activity in CD, but unreliable in UC. Hydro-MRI provides useful information for the differentiation of CD and UC. (orig.) [German] Zielsetzung: Vergleich der Hydro-MRT mi Koloskopie und Histopathologie bezueglich der Beurteilung der entzuendlichen Aktivitaet und der Differenzierung entzuendlicher Darmerkrankungen. Patienten und Methodik: Bei 27 Patienten mit einer entzuendlichen Darmerkrankung wurden nach einer oralen Darmkontrastierung mit 1000 ml einer 2,5%igen Mannitolloesung und einer rektalen Darmkontrastierung mit 250-500 ml einer 0,9%igen NaCl-Loesung atemangehaltene transversale und koronare Sequenzen {+-} intravenoese Gd-DTPA-Applikation (HASTE

  2. Magneto--thermal evolution of neutron stars

    CERN Document Server

    Pons, J A; Geppert, U

    2008-01-01

    We study the mutual influence of thermal and magnetic evolution in a neutron star's crust in axial symmetry. Taking into account realistic microphysical inputs, we find the heat released by Joule effect consistent with the circulation of currents in the crust, and we incorporate its effects in 2D cooling calculations. We solve the induction equation numerically using a hybrid method (spectral in angles, but a finite--differences scheme in the radial direction), coupled to the thermal diffusion equation. We present the first long term 2D simulations of the coupled magneto-thermal evolution of neutron stars. This substantially improves previous works in which a very crude approximation in at least one of the parts (thermal or magnetic diffusion) has been adopted. Our results show that the feedback between Joule heating and magnetic diffusion is strong, resulting in a faster dissipation of the stronger fields during the first million years of a NS's life. As a consequence, all neutron stars born with fields larg...

  3. Temporal variations of NDVI and correlations between NDVI and hydro-climatological variables at Lake Baiyangdian, China

    Science.gov (United States)

    Wang, Fei; Wang, Xuan; Zhao, Ying; Yang, Zhifeng

    2014-09-01

    In this paper, correlations between vegetation dynamics (represented by the normalized difference vegetation index (NDVI)) and hydro-climatological factors were systematically studied in Lake Baiyangdian during the period from April 1998 to July 2008. Six hydro-climatological variables including lake volume, water level, air temperature, precipitation, evaporation, and sunshine duration were used, as well as extracted NDVI series data representing vegetation dynamics. Mann-Kendall tests were used to detect trends in NDVI and hydro-climatological variation, and a Bayesian information criterion method was used to detect their abrupt changes. A redundancy analysis (RDA) was used to determine the major hydro-climatological factors contributing to NDVI variation at monthly, seasonal, and yearly scales. The results were as follows: (1) the trend analysis revealed that only sunshine duration significantly increased over the study period, with an inter-annual increase of 3.6 h/year ( p RDA showed that evaporation and temperature were highly correlated with monthly changes in NDVI. At larger time scales, however, water level and lake volume gradually became more important than evaporation and precipitation in terms of their influence on NDVI. These results suggest that water availability is the most important factor in vegetation restoration. In this paper, we recommend a practical strategy for lake ecosystem restoration that takes into account changes in NDVI.

  4. Ultrafast magneto-photocurrents as probe of anisotropy relaxation in GaAs

    CERN Document Server

    Schmidt, Christian B; Pierz, Klaus; Bieler, Mark

    2016-01-01

    We induce ultrafast photocurrents in a GaAs crystal exposed to a magnetic field by optical femtosecond excitation. The magneto-photocurrents are studied by time-resolved detection of the simultaneously emitted THz radiation. We find that their dynamics differ considerably from the dynamics of other photocurrents which are expected to follow the temporal shape of the optical intensity. We attribute this difference to the influence of carrier-anisotropy relaxation on the magneto-photocurrents. Our measurements show that the anisotropy relaxation for carrier densities ranging between $10^{16}$ cm$^{-3}$ and $5 \\times 10^{17}$ cm$^{-3}$ occurs on two different time scales. While the slow time constant is approximately 100 fs long and most likely governed by electron-phonon scattering, the fast time constant is on the order of 10 fs and presumably linked to the valence band. Our studies not only help to better understand the microscopic origins of optically induced currents but - being even more important - show t...

  5. Tunnel Magneto Resistance of Fe/Insulator/Fe

    Science.gov (United States)

    Aryee, Dennis; Seifu, Dereje

    Tri-layer thin films of Fe/Insulator/Fe were synthesized using magnetron DC/ RF sputtering with MgO insulator and Bi2Te3 topological insulators as middle buffer layer. The multi-layered samples thus produced were studied using in-house built magneto-optic Kerr effect (MOKE) instrument, vibrating sample magnetometer (VSM), torque magnetometer (TMM), AFM, MFM, and magneto-resistance (MR). This system, that is Fe/Insulator/Fe on MgO(100) substrate, is a well-known tunnel magneto resistance (TMR) structure often used in magnetic tunnel junction (MTJ) devices. TMR effect is a method by which MTJs are used in developing magneto-resistive random access memory (MRAM), magnetic sensors, and novel logic devices. The main purpose behind this research is to measure the magnetic anisotropy of Fe/Insulator /Fe structure and correlate it to magneto-resistance. In this presentation, we will present results from MOKE, VSM, TMM, AFM, MFM, and MR studies of Fe/Insulator/Fe on MgO(100). We would like to acknowledge support by NSF-MRI-DMR-1337339.

  6. Magneto-optical non-reciprocal devices in silicon photonics

    Directory of Open Access Journals (Sweden)

    Yuya Shoji

    2014-01-01

    Full Text Available Silicon waveguide optical non-reciprocal devices based on the magneto-optical effect are reviewed. The non-reciprocal phase shift caused by the first-order magneto-optical effect is effective in realizing optical non-reciprocal devices in silicon waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer enhances the magneto-optical phase shift, which reduces the device footprints. A surface activated direct bonding technique was developed to integrate a magneto-optical garnet crystal on the silicon waveguides. A silicon waveguide optical isolator based on the magneto-optical phase shift was demonstrated with an optical isolation of 30 dB and insertion loss of 13 dB at a wavelength of 1548 nm. Furthermore, a four port optical circulator was demonstrated with maximum isolations of 15.3 and 9.3 dB in cross and bar ports, respectively, at a wavelength of 1531 nm.

  7. Towards a Manitoba Hydro boreal woodland caribou strategy: Outcomes from Manitoba Hydro boreal woodland caribou workshop

    Directory of Open Access Journals (Sweden)

    Fiona E. Scurrah

    2012-03-01

    Full Text Available Manitoba Hydro is responsible for the continued supply of energy to meet the needs of the province and is committed to protecting the environment when planning the construction and operation of its facilities. Corporate policy dictates ongoing improvement of Environmental Management Systems (EMS in order to meet or surpass regulatory requirements. Environmental objectives are reviewed annually and programs are modified when necessary to address improvements in environmental performance. Manitoba Hydro plans and constructs major transmission projects throughout northern Manitoba which includes areas occupied by boreal woodland caribou. In recognition of the potential issues associated with hydro transmission construction in boreal caribou range, Manitoba Hydro hosted an expert workshop on May 8, 2007 to provide objective advice in the development of a draft corporate strategy that effectively directs targeted monitoring and research for environmental assessment and mitigation. The workshop focused on assessing the potential threats to boreal woodland caribou from a transmission line construction and operation perspective, and identifying appropriate approaches in site selection and environmental assessment (SSEA and long-term monitoring and research. A total of nine threat categories were reviewed to determine the degree and magnitude of potential effects that may result from transmission construction and operation; and of the original nine, five final threat categories were delineated. The main elements of the workshop provided strategic approaches for proactive pre-construction monitoring, research on recruitment and mortality for local populations impacted by ROWs and control areas, and various habitat monitoring, management, and mitigation techniques. Research and monitoring priorities have been identified and continued collaboration with Manitoba Conservation and other land users were also identified.

  8. Hydro-Quebec seeks open access in the US

    Energy Technology Data Exchange (ETDEWEB)

    Bright, D.; Salaff, S.

    1996-02-01

    Issues relevant to a recent U.S. Federal Energy Regulatory Commission (FERC) order to Hydro-Quebec to open up access to its transmission system, as a condition of participation by a Hydro-Quebec subsidiary in energy marketing in the United States, were outlined. Hydro-Quebec was reported to be considering its options, and has not yet responded to the order. Hydro-Quebec currently sells its energy at the US border in all export transactions. With the approval of FERC, Energy Alliance Partnership would be in a position to offer its customers choices in selling, buying, borrowing and loaning natural gas , electricity and other fuels, as a wholesaler in the electricity and natural gas business. FERC was concerned that by allowing greater market penetration by Hydro-Quebec and its partners could lead to generation dominance, or affiliate abuse. Hydro-Quebec`s position is that transmission constraints and legal limitations, as well as Hydro-Quebec`s obligation to serve its own provincial load, are extremely unlikely to allow its current 10% share of the U.S.market to increase significantly in the foreseeable future.

  9. Experience of pico/micro hydro based power generation

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, S.S. [Indian Inst. of Technology, Delhi, New Delhi (India). Dept. of Electrical Engineering

    2010-07-01

    Although India has approximately 150,000 megawatts of hydro potential, only a small portion is tapped. There is also significant untapped hydro potential in many developing countries such as Nepal, Bhutan, Vietnam, Indonesia and regions in South America and Africa. Small-scale hydroelectric power systems with capacities of up to a few megawatts are eco-friendly and sustainable. They can be classified based on unit sizes as pico (u pto 10 kilowatts), micro (10-100 kilowatts) and mini (100 kilowatts to a few megawatts) hydro systems. Mini hydro systems are always grid connected while micro can be either grid connected or off grid. Pico is always off grid. In India, there are thousands of favorable sites in this range that should be tapped for distributed power generation to electrify local communities. This need is reflected by the global emphasis on distributed power generation as well as the Government of India's policy to promote this type of power generation. A working stand alone pico-hydro power generating system has been successfully installed in 5 sites in Karnataka. The purpose of the project was to demonstrate the technical, managerial and economic feasibility of setting up small hydro projects in remote hilly areas of Karnataka, India and its positive environmental impact. The presentation discussed the site selection criteria; installed sites of pico hydro; system description; parts of the system; the electric load controller; types of electronic load controllers; and a description of the unit and control scheme. tabs., figs.

  10. Innovative private micro-hydro power development in Rwanda

    Energy Technology Data Exchange (ETDEWEB)

    Pigaht, Maurice; Van der Plas, Robert J. [MARGE-Netherlands, Brem 68, 7577 EW Oldenzaal (Netherlands)

    2009-11-15

    Under the 'Private Sector Participation in Micro-Hydro Development Project in Rwanda', four newly registered Rwandan companies are each constructing a micro-hydro electricity plant (100-500 kW) and building a low-voltage distribution grid. These companies financed their plants through their own equity and debt with support from the PSP Hydro project. This support comprised a subsidy of 30-50% of investment costs, technical and business development assistance, project monitoring and financial controlling. The experiences gained so far have important implications for similar future micro-hydro energy sector development projects and this paper puts forward three key messages: (1) institutional arrangements rather than technical quality determine the success of such projects; (2) truly sustainable rural electrification through micro-hydro development demands a high level of local participation at all levels and throughout all project phases, not just after plant commissioning; and (3) real impact and sustainability can be obtained through close collaboration of local private and financial sector firms requiring only limited external funds. In short, micro-hydro projects can and will be taken up by local investors as a business if the conditions are right. Applying these messages could result in an accelerated uptake of viable micro-hydro activities in Rwanda, and in the opinion of the authors elsewhere too. (author)

  11. Hydro-Quebec; other times, other challenges; Hydro-Quebec; autres temps, autres defis

    Energy Technology Data Exchange (ETDEWEB)

    Belanger, Y.; Comeau, R.

    1995-12-31

    This book provides an overview of the past history and expected future development of Hydro-Quebec through a series of papers presented at a conference in Montreal in 1994. The papers focus on six principal themes: (1) fifty years of history and symbolism, (2) stakes and future choices,(3) economic development and innovation, (4) Quebec northern policy, (5) energy choices and the environment, and (6) the issue of privatizing Hydro-Quebec. The intimate relationship of Hydro-Quebec, long perceived as the major pillar of the economic development of Quebec, and fundamental to the evolution of the idea of a Quebec nation, were also explored. Although the historical approach was clearly preferred by most of the contributors, the uncertain future of the giant utility in the face of the continent-wide movement towards competition and open access, received the bulk of the attention. The special complications introduced by the resistance to hydroelectric power development of Quebec`s native population, environmental concerns, and the quest for sustainable development, also have been treated extensively. refs., tabs., figs.

  12. High hopes for Indian small hydro

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, I.M.

    2001-02-01

    This article highlights the Indian government's steps to encourage the development of small-scale hydroelectric power plants, the funding of demonstration schemes involving the upgrading of water-driven mills for local and domestic power generation, and the installation of portable micro hydro-sets. Details are given of the implementation of a small-scale hydroelectric power project, funded by the United Nations Development Programme, to optimise development in the sub-Himalayan region, and the work done to-date and the achievements of the project are discussed. The sharing of the experience gained with other countries having similar hilly remote areas is considered, and hurdles that may slow down the progress of small hydroelectric programmes are listed.

  13. Magneto-frictional Modeling of Coronal Nonlinear Force-free Fields. I. Testing with Analytic Solutions

    Science.gov (United States)

    Guo, Y.; Xia, C.; Keppens, R.; Valori, G.

    2016-09-01

    We report our implementation of the magneto-frictional method in the Message Passing Interface Adaptive Mesh Refinement Versatile Advection Code (MPI-AMRVAC). The method aims at applications where local adaptive mesh refinement (AMR) is essential to make follow-up dynamical modeling affordable. We quantify its performance in both domain-decomposed uniform grids and block-adaptive AMR computations, using all frequently employed force-free, divergence-free, and other vector comparison metrics. As test cases, we revisit the semi-analytic solution of Low and Lou in both Cartesian and spherical geometries, along with the topologically challenging Titov-Démoulin model. We compare different combinations of spatial and temporal discretizations, and find that the fourth-order central difference with a local Lax-Friedrichs dissipation term in a single-step marching scheme is an optimal combination. The initial condition is provided by the potential field, which is the potential field source surface model in spherical geometry. Various boundary conditions are adopted, ranging from fully prescribed cases where all boundaries are assigned with the semi-analytic models, to solar-like cases where only the magnetic field at the bottom is known. Our results demonstrate that all the metrics compare favorably to previous works in both Cartesian and spherical coordinates. Cases with several AMR levels perform in accordance with their effective resolutions. The magneto-frictional method in MPI-AMRVAC allows us to model a region of interest with high spatial resolution and large field of view simultaneously, as required by observation-constrained extrapolations using vector data provided with modern instruments. The applications of the magneto-frictional method to observations are shown in an accompanying paper.

  14. Magneto-frictional Modeling of Coronal Nonlinear Force-free Fields. II. Application to Observations

    Science.gov (United States)

    Guo, Y.; Xia, C.; Keppens, R.

    2016-09-01

    A magneto-frictional module has been implemented and tested in the Message Passing Interface Adaptive Mesh Refinement Versatile Advection Code (MPI-AMRVAC) in the first paper of this series. Here, we apply the magneto-frictional method to observations to demonstrate its applicability in both Cartesian and spherical coordinates, and in uniform and block-adaptive octree grids. We first reconstruct a nonlinear force-free field (NLFFF) on a uniform grid of 1803 cells in Cartesian coordinates, with boundary conditions provided by the vector magnetic field observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) at 06:00 UT on 2010 November 11 in active region NOAA 11123. The reconstructed NLFFF successfully reproduces the sheared and twisted field lines and magnetic null points. Next, we adopt a three-level block-adaptive grid to model the same active region with a higher spatial resolution on the bottom boundary and a coarser treatment of regions higher up. The force-free and divergence-free metrics obtained are comparable to the run with a uniform grid, and the reconstructed field topology is also very similar. Finally, a group of active regions, including NOAA 11401, 11402, 11405, and 11407, observed at 03:00 UT on 2012 January 23 by SDO/HMI is modeled with a five-level block-adaptive grid in spherical coordinates, where we reach a local resolution of 0\\buildrel{\\circ}\\over{.} 06 pixel-1 in an area of 790 Mm × 604 Mm. Local high spatial resolution and a large field of view in NLFFF modeling can be achieved simultaneously in parallel and block-adaptive magneto-frictional relaxations.

  15. Magneto transport in crossed electric and magnetic fields in compensated bulk GaN

    Science.gov (United States)

    Syngayivska, G. I.; Korotyeyev, V. V.; Kochelap, V. A.; Varani, L.

    2016-09-01

    Low-temperature high-field electron transport is studied for compensated bulk GaN subjected to crossed electric and magnetic fields. The electron kinetics, distribution function, and field dependencies of the magneto transport characteristics are analyzed by using the Monte-Carlo method. At zero magnetic field, for an ionized impurity concentration of 1016 cm-3 and an electron concentration of 1015 cm-3, it is shown that dissipative streaming transport with a strong anisotropic electron distribution in the momentum space is realized at electric fields in the range 3 -10 kV/cm and for a lattice temperature of 30 K. The magnetic field destroys the dissipative streaming transport. Indeed, for a magnetic field greater than 4 T, the electrons are predominantly confined in a region of the momentum space where their energy is smaller than the optical phonon energy and the strong inelastic scattering by optical phonons is practically eliminated. A quasi-ballistic electron transport occurs in the form of a vortex-like motion in the momentum space. The axis of rotation of this vortex coincides with the average electron momentum. A general analysis of the distribution function suitable for any configuration of the Hall circuit is presented. The main magneto transport characteristics (dissipative current, Hall current, and Hall electric field) are studied for the short and open Hall circuits. We show that the magneto transport measurements can provide valuable information on the main features of the electron distribution function and electron dynamics in GaN. Finally, we suggest that the strong dependency of the dissipative current on the parameters of the Hall circuit can be used for current modulation and current switching.

  16. 76 FR 42124 - River Bounty, Inc.; Renew Hydro, LLC; Notice of Transfer of Exemption

    Science.gov (United States)

    2011-07-18

    ... Energy Regulatory Commission River Bounty, Inc.; Renew Hydro, LLC; Notice of Transfer of Exemption 1. By...\\ has been transferred to Renew Hydro, LLC. The project is located on the Susquehanna River in...\\ American Hydro Power Co., 19 FERC ] 62,426 (1982). 2. Renew Hydro, LLC, located at 1800 Route 34, Suite...

  17. Multifrequency transverse Faraday effect in single magneto-dielectric microspheres

    CERN Document Server

    Maksymov, Ivan S

    2014-01-01

    We propose using a single magneto-dielectric microsphere as a device for enhancing the transverse Faraday effect at multiple wavelengths at the same time. Although the diameter of the sphere can be $<1$ $\\mu$m, the numerically predicted strength of its magneto-optical (MO) response can be an order of magnitude stronger than in MO devices based on thick magnetic plates. The MO response of a microsphere is also comparable with that of subwavelength magneto-dielectric gratings which, however, operate at a single wavelength and occupy a large area. In contrast to gratings and thick plates, the compact size of the microsphere and its capability to support spin-wave excitations make it suitable for applications in nanophotonics, imaging systems, and magnonics.

  18. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang

    2017-09-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  19. Love wave propagation in layered magneto- electro-elastic structures

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    An analytical approach was taken to investigate Love wave propagation in a layered magneto-electro-elastic structure, where a piezomagnetic (or piezoelectric) mate-rial thin layer was bonded to a semi-infinite piezoelectric (or piezomagnetic) sub-strate. Both piezoelectric and piezomagnetic ceramics were polarized in the anti-plane (z-axis) direction. The analytical solution of dispersion relations was obtained for magneto-electrically open and short boundary conditions. The phase velocity, group velocity, magneto-electromechanical coupling factor, electric po-tential, and magnetic potential were calculated and discussed in detail. The nu-merical results show that the piezomagnetic effects have remarkable effect on the propagation of Love waves in the layered piezomagnetic/piezoelectric structures.

  20. Love wave propagation in layered magneto-electro-elastic structures

    Institute of Scientific and Technical Information of China (English)

    DU JianKe; JIN XiaoYing; WANG Ji

    2008-01-01

    An analytical approach was taken to investigate Love wave propagation in a layered magneto-electro-elastic structure,where a piezomagnetic (or piezoelectric) mate-rial thin layer was bonded to a semi-infinite piezoelectric (or piezomagnetic) sub-strate.Both piezoelectric and piezomagnetic ceramics were polarized in the anti-plane (z-axis) direction.The analytical solution of dispersion relations was obtained for magneto-electrically open and short boundary conditions.The phase velocity,group velocity,magneto-electromechanical coupling factor,electric po-tential,and magnetic potential were calculated and discussed in detail.The nu-merical results show that the piezomagnetic effects have remarkable effect on the propagation of Love waves in the layered piezomagnetic/piezoelectric structures.

  1. Magneto-thermally activated spin-state transition in La0.95Ca0.05CoO3: magnetically-tunable dipolar glass and giant magneto-electricity.

    Science.gov (United States)

    Pandey, Suchita; Kumar, Jitender; Awasthi, A M

    2016-03-01

    The magneto-dielectric spectroscopy of La0.95Ca0.05CoO3 covering the crossover of spin states reveals the strong coupling of its spin and dipolar degrees of freedom. The signature of the spin-state transition at 30 K clearly manifests in the magnetization data at a 1 Tesla optimal field. Our Co L3,2-edge X-ray absorption spectrum on the doped specimen is consistent with its suppressed low-to-intermediate spin-state transition temperature at ∼30 K compared to ∼150 K, documented for pure LaCoO3. The dispersive activation step in the dielectric constant with the associated relaxation peak in imaginary permittivity characterize the allied influence of coexistent spin-states on the dielectric character. Dipolar relaxation in the low-spin regime below the transition temperature is partly segmental (Vogel-Fulcher-Tamman (VFT) kinetics) and features magnetic-field tunability, whereas in the low/intermediate-spin disordered state above ∼30 K, it is uncorrelated (Arrhenic kinetics) and almost impervious to the magnetic field H. Kinetics-switchover defines the dipolar-glass transition temperature Tg(H) (=27 K|0T), below which their magneto-thermally-activated cooperative relaxations freeze out by the VFT temperature T0(H) (=15 K|0T). An applied magnetic field facilitates thermal activation in toggling the low spins up into the intermediate states. Consequently, the downsized dipolar-glass segments in the low-spin state and the independent dipoles in the intermediate state exhibit accelerated dynamics. A critical 5 Tesla field collapses the entire relaxation kinetics into a single Arrhenic behaviour, signaling that the dipolar glass is completely devitrified under all higher fields. The magneto-electricity (ME) spanning sizeable thermo-spectral range registers diverse signatures here in kinetic, spectral, and field behaviors, in contrast to the static/perturbative ME observed close to the spin-ordering in typical multiferroics. Intrinsic magneto-dielectricity (50%) along

  2. Magneto-chemotaxis in sediment: first insights.

    Directory of Open Access Journals (Sweden)

    Xuegang Mao

    Full Text Available Magnetotactic bacteria (MTB use passive alignment with the Earth magnetic field as a mean to increase their navigation efficiency in horizontally stratified environments through what is known as magneto-aerotaxis (M-A. Current M-A models have been derived from MTB observations in aqueous environments, where a >80% alignment with inclined magnetic field lines produces a one-dimensional search for optimal living conditions. However, the mean magnetic alignment of MTB in their most widespread living environment, i.e. sediment, has been recently found to be <1%, greatly reducing or even eliminating the magnetotactic advantage deduced for the case of MTB in water. In order to understand the role of magnetotaxis for MTB populations living in sediment, we performed first M-A observations with lake sediment microcosms. Microcosm experiments were based on different combinations of (1 MTB position with respect to their preferred living depth (i.e. above, at, and below, and (2 magnetic field configurations (i.e. correctly and incorrectly polarized vertical fields, horizontal fields, and zero fields. Results suggest that polar magnetotaxis is more complex than implied by previous experiments, and revealed unexpected differences between two types of MTB living in the same sediment. Our main findings are: (1 all investigated MTB benefit of a clear magnetotactic advantage when they need to migrate over macroscopic distances for reaching their optimal living depth, (2 magnetotaxis is not used by all MTB under stationary, undisturbed conditions, (3 some MTB can rely only on chemotaxis for macroscopic vertical displacements in sediment while other cannot, and (4 some MTB use a fixed polar M-A mechanisms, while other can switch their M-A polarity, performing what can be considered as a mixed polar-axial M-A. These observations demonstrate that sedimentary M-A is controlled by complex mechanical, chemical, and temporal factors that are poorly reproduced in aqueous

  3. Quantifying Barotrauma Risk to Juvenile Fish during Hydro-turbine Passage

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, Marshall C.; Serkowski, John A.; Ebner, Laurie L.; Sick, Mirjam; Brown, Richard S.; Carlson, Thomas J.

    2014-03-15

    We introduce a method for hydro turbine biological performance assessment (BioPA) to bridge the gap between field and laboratory studies on fish injury and turbine engineering design. Using this method, a suite of biological performance indicators is computed based on simulated data from a computational fluid dynamics (CFD) model of a proposed hydro turbine design. Each performance indicator is a measure of the probability of exposure to a certain dose of an injury mechanism. If the relationship between the dose of an injury mechanism (stressor) and frequency of injury (dose-response) is known from laboratory or field studies, the likelihood of fish injury for a turbine design can be computed from the performance indicator. By comparing the values of the indicators from various turbine designs, engineers and biologists can identify the more-promising designs and operating conditions to minimize hydraulic conditions hazardous to passing fish. In this paper, the BioPA method is applied to estimate barotrauma induced mortal injury rates for Chinook salmon exposed to rapid pressure changes in Kaplan-type hydro turbines. Following the description of the general method, application of the BioPA to estimate the probability of mortal injury from exposure to rapid decompression is illustrated using a Kaplan hydro turbine at the John Day Dam on the Columbia River in the Pacific Northwest region of the USA. The estimated rates of mortal injury increased from 0.3% to 1.7% as discharge through the turbine increased from 334 to 564 m3/s for fish assumed to be acclimated to a depth of 5 m. The majority of pressure nadirs occurred immediately below the runner blades, with the lowest values in the gap at the blade tips and just below the leading edge of the blades. Such information can help engineers focus on problem areas when designing new turbine runners to be more fish-friendly than existing units.

  4. The Selection of Cooling systems of Giant Hydro-Generators

    Institute of Scientific and Technical Information of China (English)

    Li Dingzhong

    2010-01-01

    @@ The selection of cooling system for hydro-generator in Ertan Hydropower Station is reviewed in this pap(ar) The new viewpoint on air-cooled system of hydraul(is)generator of recent years is analyzed and described. That is, "Full air-cooled system is always preferred to inner water cooling system in hydro-generator." Moreov() the decision process and corresponding actions of aircooled system design for hydro-generator in Longtan Hydropower Station, Xiaowan Hydropower Station and Laxiwa Hydropower Station are introduced.

  5. Development of Key Technologies of Large Hydro Unit in HEC

    Institute of Scientific and Technical Information of China (English)

    Wu Weizhang

    2010-01-01

    @@ Introduction to HEC Harbin Electric Machinery Company Limited (HEC) is a pivotal company that produces large electric machinery and accessorial control equipment in China.The hydro units made by HEC have accounted for about half of the large-and medium-size hydropower units installed in China,while the thermal generator units occupy about one-third of the total thermal capacity of China.HEC has the ability to develop,design and manufacture products independently,and its typical products include hydro turbine,hydro generator,turbo generator and control equipment.

  6. Effects of evolving hydro-geomorphic connectivity on the erosion response during the initial phase of landform development

    Science.gov (United States)

    Schneider, Anna

    2017-04-01

    The development of land surfaces in non-equilibrium conditions is often characterized by the emergence of drainage networks, a rapid increase of hydro-geomorphic connectivity and a non-linear response of erosion to precipitation events, and conceptual models of landform evolution have related drainage network evolution, hydro-geomorphic connectivity and non-linear erosion behavior. Because of the high dynamics of hydro-geomorphic structures and connectivity during initial phases of landform evolution, detailed studies on surface development on young land surfaces can help to further elucidate mechanisms and parameters relevant for hydro-geomorphic connectivity. In this study, we applied the landscape evolution model CAESAR for assessing different scenarios of surface structure evolution during the initial years of surface development in small catchments. Data from an artificially-created experimental catchment were used for model calibration and validation, and simulations were carried out for the experimental catchment surface and an idealized slope model. Hourly precipitation records for the experimental catchment were rearranged in several scenarios to assess relations between the erosional response of the catchments and states of hydro-geomorphic surface development. The simulations clearly show non-linear erosion responses of the developing surface, related to its developing hydro-geomorphic connectivity: Simulations with high-intensity precipitation events during the very first years of development resulted in clearly higher rill network density and sediment discharge than simulations with high-intensity events during later stages of surface evolution. A detailed analysis of surface flow patterns shows that the reduced erosion response of the further developed surface is a consequence of higher connectivity, combined with a shift from transport- to detachment-limited erosion along major drainage paths. These results indicate that increased surface hydro

  7. Tuning Coler Magnetic Current Apparatus with Magneto-Acoustic Resonance

    Science.gov (United States)

    Ludwig, Thorsten

    An attempt was made to tune the Coler magnetic current apparatus with the magneto acoustic resonance of the magnetic rods. Measurements with a replica of the famous Coler "Magnetstromapparat" were conducted. In order to tune the acoustic, magnetic and electric resonance circuits of the Coler device the magneto-acoustic resonance was measured with a frequency scan through a function generator and a lock-in amplifier. The frequency generator was powering a driving coil, while the lock-in was connected to a pickup coil. Both coils were placed on a magnetic rod. Resonances were observed up to the 17th harmonic. The quality Q of the observed resonances was 270. To study the magneto-acoustic resonance in the time domain a pair of Permendur rods were employed. The magneto-acoustic resonances of the Permendur rods were observed with an oscilloscope. Spectra of the magneto acoustic resonance were measured for the Permendur rods and for a Coler replica magnet in the frequency range from 25 kHz to 380 kHz. The next step was to bring the resonances of the Permendur rods close together so that they overlap. The 10thharmonic was chosen because it was close to the 180 kHz that Hans Coler related to ferromagnetism. Further more magneto-acoustic coupling between the Permendur rods was studied. Finally the question was explored if Hans Coler converted vacuum fluctuations via magnetic and acoustic resonance into electricity. There is a strong connection between magnetism and quantum field zero point energy (ZPE). An outlook is given on next steps in the experiments to unveil the working mechanism of the Coler magnetic current apparatus.

  8. The Double Jones Birefringence in Magneto-electric Medium

    CERN Document Server

    Mahmood, Waqas

    2014-01-01

    In this paper, the Maxwell's equations for the tensorial magneto-electric (ME) medium have been solved which in fact is the extension of anisotropic nonmagnetic medium. All of the dielectric permittivity, magnetic permeability and the ME tensors are considered. The transverse polarization is shown explicitly and the propagation of electromagnetic wave in the ME medium is found to have the Double Jones Birefringence. We also find the condition of D'yakonov surface wave for magneto-isotropic but with ME anisotropic medium. Especially when the incident angle is $\\frac{\\pi}{4}$, it may be measurable in principle.

  9. Magneto-optical system for high speed real time imaging

    Science.gov (United States)

    Baziljevich, M.; Barness, D.; Sinvani, M.; Perel, E.; Shaulov, A.; Yeshurun, Y.

    2012-08-01

    A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

  10. Introducing Magneto-Optical Functions into Soft Materials

    Science.gov (United States)

    2017-05-03

    AFRL-AFOSR-JP-TR-2017-0036 Introducing Magneto-Optical Functions into Soft Materials Chia-Liang ’Charlie’ Cheng National Dong Hwa University No 1 Sec...COVERED (From - To) 28 Mar 2013 to 27 Mar 2016 4. TITLE AND SUBTITLE Introducing Magneto-Optical Functions into Soft Materials 5a.  CONTRACT NUMBER 5b...excited states by measuring the capacitance as a function of magnetic field without and with photoexcitation respectively. 2.1 -d electron coupling in

  11. Definition of scarcity-based water pricing policies through hydro-economic stochastic programming

    Science.gov (United States)

    Macian-Sorribes, Hector; Pulido-Velazquez, Manuel; Tilmant, Amaury

    2014-05-01

    One of the greatest current issues in integrated water resources management is to find and apply efficient and flexible management policies. Efficient management is needed to deal with increased water scarcity and river basin closure. Flexible policies are required to handle the stochastic nature of the water cycle. Scarcity-based pricing policies are one of the most promising alternatives, which deal not only with the supply costs, but also consider the opportunity costs associated with the allocation of water. The opportunity cost of water, which varies dynamically with space and time according to the imbalances between supply and demand, can be assessed using hydro-economic models. This contribution presents a procedure to design a pricing policy based on hydro-economic modelling and on the assessment of the Marginal Resource Opportunity Cost (MROC). Firstly, MROC time series associated to the optimal operation of the system are derived from a stochastic hydro-economic model. Secondly, these MROC time series must be post-processed in order to combine the different space-and-time MROC values into a single generalized indicator of the marginal opportunity cost of water. Finally, step scarcity-based pricing policies are determined after establishing a relationship between the MROC and the corresponding state of the system at the beginning of the time period (month). The case study of the Mijares river basin (Spain) is used to illustrate the method. It consists in two reservoirs in series and four agricultural demand sites currently managed using historical (XIVth century) rights. A hydro-economic model of the system has been built using stochastic dynamic programming. A reoptimization procedure is then implemented using SDP-derived benefit-to-go functions and historical flows to produce the time series of MROC values. MROC values are then aggregated and a statistical analysis is carried out to define (i) pricing policies and (ii) the relationship between MROC and

  12. A realistic 3+1D Viscous Hydro Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Romatschke, Paul [Univ. of Colorado, Boulder, CO (United States)

    2015-05-31

    DoE funds were used as bridge funds for the faculty position for the PI at the University of Colorado. The total funds for the Years 3-5 of the JET Topical Collaboration amounted to about 50 percent of the academic year salary of the PI.The PI contributed to the JET Topical Collaboration by developing, testing and applying algorithms for a realistic simulation of the bulk medium created in relativistic ion collisions.Specifically, two approaches were studied, one based on a new Lattice-Boltzmann (LB) framework, and one on a more traditional viscous hydro-dynamics framework. Both approaches were found to be viable in principle, with the LB approach being more elegant but needing still more time to develop.The traditional approach led to the super-hybrid model of ion collisions dubbed 'superSONIC', and has been successfully used for phenomenology of relativistic heavy-ion and light-on-heavy-ion collisions.In the time-frame of the JET Topical Collaboration, the Colorado group has published 15 articles in peer-reviewed journals, three of which were published in Physical Review Letters. The group graduated one Master student during this time-frame and two more PhD students are expected to graduate in the next few years. The PI has given more than 28 talks and presentations during this period.

  13. Magneto-transport characteristics of a 2D electron system driven to negative magneto-conductivity by microwave photoexcitation.

    Science.gov (United States)

    Mani, R G; Kriisa, A

    2013-12-11

    Negative diagonal magneto-conductivity/resistivity is a spectacular- and thought provoking-property of driven, far-from-equilibrium, low dimensional electronic systems. The physical response of this exotic electronic state is not yet fully understood since it is rarely encountered in experiment. The microwave-radiation-induced zero-resistance state in the high mobility GaAs/AlGaAs 2D electron system is believed to be an example where negative magneto-conductivity/resistivity is responsible for the observed phenomena. Here, we examine the magneto-transport characteristics of this negative conductivity/resistivity state in the microwave photo-excited two-dimensional electron system (2DES) through a numerical solution of the associated boundary value problem. The results suggest, surprisingly, that a bare negative diagonal conductivity/resistivity state in the 2DES under photo-excitation should yield a positive diagonal resistance, with a concomitant sign reversal in the Hall voltage.

  14. Does pH influence soil hydro-mechanical properties?

    Science.gov (United States)

    Chaplain, V.; Défossez, P.; Delarue, G.; Dexter, A. R.; Richard, G.; Tessier, D.

    2009-04-01

    Does pH influence soil hydro-mechanical properties ? V. Chaplain1, P. Défossez2, G. Delarue1, A.R. Dexter3, G. Richard3 and D. Tessier1. 1 UR INRA PESSAC RD 10, F-78026 Versailles cedex 2 UMR INRA/URCA FARE, 2 Esplanade Roland Garros, BP 224 F-51686 Reims cedex 2 3 UR INRA Sols 2163 Avenue de la Pomme de Pin - CS 40001 ARDON F-45075 Orléans Cedex 2 Corresponding author : chaplain@versailles.inra.fr Structure of soils and its dynamic, physico-chemistry of the interface are of a great importance in the fate of organic pollutants because it governs the accessibility of pollutants to micro-organisms. The soil structure of soils is related to physical parameters (texture, density, water content) but the physico-chemical properties of the interface is not considered. In this study we performed hydro-mechanical measurements on soil samples taken from the 42-plot long-term experiment in Versailles. Indeed six plots were selected to cover a large range of pH values from acid (3.5) to alkaline (8.2) due to the repeated application of fertilizers. Soils were taken in the 0-20 cm and in the 30-35 cm layer out of the ploughed zone. All soils had similar texture and composition with low organic carbon. Therefore pH changes the surface charges and hydrophobicity that are implied in aggregation process. The two layers had the same pH values. The precompression stress Pc and the compression index Cc were derived from confined compression tests performed on remoulded soil samples (density 1.45 g/cm3) at saturation. Results shows that the precompression stress increased at pH lower than 4. In acid case, precompression stress was higher in subsoil. This increase of Pc was attributed to the hydrophobicity due in part to the condensation of charges probably sensitive to the humectation/dessication processes.

  15. Influence of MR damper modeling on vehicle dynamics

    Science.gov (United States)

    de-J Lozoya-Santos, Jorge; Morales-Menendez, Ruben; Ramirez-Mendoza, Ricardo A.; Vivas-Lopez, Carlos A.

    2013-12-01

    The influence of magneto-rheological damper modeling in vehicle dynamics analysis is studied. Several tests using CarSim™ compare a four-corner controlled semi-active suspension for two different magneto-rheological damper models. The magneto-rheological damper characteristics were identified from experimental data. A model-free controller discards the influence of control and emphasizes the compliance of the magneto-rheological damper model; the characteristics of the vehicle index performance considered were comfort, road holding, handling, roll and suspension deflection. The comparison for magneto-rheological damper dynamics and semi-active suspension covers the automotive bandwidth. The results show that high precision of a magneto-rheological damper model as an isolated feature is not enough. The magneto-rheological damper model, as a component of a vehicle suspension, needs to simulate with passive precision and variable damping forces. The findings exhibit the requisite of accurate models for evaluation of semi-active control systems in classic tests. The lack of the friction component in a magneto-rheological damper model leads to an overestimation in handling and stability.

  16. 伏牛山地区森林植被动态变化对水热条件的响应%The response of forest dynamics to hydro-thermal change in Funiu Mountain

    Institute of Scientific and Technical Information of China (English)

    张晓东; 朱文博; 崔耀平; 张静静; 朱连奇

    2016-01-01

    The response of mountain ecosystem to global change is one of hot topics in the field of forest dynamics.As an important component of mountain ecosystems,to some degree,vegetation coverage change represents the change of land cover,and can provide indication to the global change.The result from the study on the relationship between climate change and forest coverage change within different vertical natural zones could enhance our understanding about the complexity and diversity of mountain ecosystem.It also can reveal the mechanism of mountain ecosystem changes.In recent years,many studies have been conducted to explore the relationship between mountain vegetation change and climatic factors,i.e.,temperature,precipitation and so on.It should be noted that,the study area,Funiu Mountain is located at a transitional region between the north subtropical zone and warm temperate zone in China.The plant flora in the Funiu Mountain is complicated and very sensitive to the global climate change.In this study,the H J-1 satellite data were used to extract forest cover types in the Funiu Mountain region.This paper adopted the S-G filtering algorithm to reconstruct the MODIS EVI (Enhanced Vegetation Index) time-series data form 2000 to 2013.Combined with the temperature with precipitation of the same study period,the response of different forest types to hydrothermal condition changes was analyzed based on the linear regression,correlation analysis,and ANUSPLIN interpolation.The results showed that:(1) the region of Funiu Mountain boasts high forest coverage,and mean EVI reached 0.48,which also showed a gradually ascending trend in recent 14 years.However,some variations were identified among different forest types.Broad-leaved deciduous forest,the dominant forest type in this region showed a noticeable growth trend.(2) There was an increasing trend in temperature in this region during the past 14 years.The increasing rate of temperature departure was about 0.27℃/ 10a,and the

  17. Temporal variations of NDVI and correlations between NDVI and hydro-climatological variables at Lake Baiyangdian, China.

    Science.gov (United States)

    Wang, Fei; Wang, Xuan; Zhao, Ying; Yang, Zhifeng

    2014-09-01

    In this paper, correlations between vegetation dynamics (represented by the normalized difference vegetation index (NDVI)) and hydro-climatological factors were systematically studied in Lake Baiyangdian during the period from April 1998 to July 2008. Six hydro-climatological variables including lake volume, water level, air temperature, precipitation, evaporation, and sunshine duration were used, as well as extracted NDVI series data representing vegetation dynamics. Mann-Kendall tests were used to detect trends in NDVI and hydro-climatological variation, and a Bayesian information criterion method was used to detect their abrupt changes. A redundancy analysis (RDA) was used to determine the major hydro-climatological factors contributing to NDVI variation at monthly, seasonal, and yearly scales. The results were as follows: (1) the trend analysis revealed that only sunshine duration significantly increased over the study period, with an inter-annual increase of 3.6 h/year (p < 0.01), whereas inter-annual NDVI trends were negligible; (2) the abrupt change detection showed that a major hydro-climatological change occurred in 2004, when abrupt changes occurred in lake volume, water level, and sunlight duration; and (3) the RDA showed that evaporation and temperature were highly correlated with monthly changes in NDVI. At larger time scales, however, water level and lake volume gradually became more important than evaporation and precipitation in terms of their influence on NDVI. These results suggest that water availability is the most important factor in vegetation restoration. In this paper, we recommend a practical strategy for lake ecosystem restoration that takes into account changes in NDVI.

  18. ANALYSIS AND ESTIMATION OF HYDRAULIC STABILITY OF FRANCIS HYDRO TURBINE

    Institute of Scientific and Technical Information of China (English)

    LAI Xi-de

    2004-01-01

    With the development of large-capacity hydro turbines, the hydraulic instability of bydro turbines has become one of the most important problems that affect the stable operation of the hydro-electric units. The hydraulic vibration and unstable operation of Francis hydro turbines are primarily caused by the unsteady pressure pulsations inside draft tubes.The forced rotating vortex core at the runner exit and the channel vortices inside Francis turbine runners are origins of the unsteady pressure pulsations when operating at partial load. This paper briefly analyzes the hydraulic instability of operation caused by the vortex core and channel vortices at partial load, then, presents a way to estimate the hydraulic stability by calculation of the flow behavior at the runner exit.The validity of estimation is examined by comparison with experimental data. This will be helpful to evaluate the alternative design and predict the hydraulic stability for both the prototype and model hydro turbines.

  19. Fouling in small hydro projects; Verschmutzung von Kleinwasserkraftwerken - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Abgottspon, A.; Staubli, T.

    2010-03-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at fouling problems encountered in small hydro installations. The report is based on ten interviews made with operators of small hydro power stations in Switzerland. A parallel project carried out in Germany is mentioned. A large variation in the degree of fouling in the various hydro power stations is noted. Sources such as leaves in autumn and algae are discussed, as are the various rinsing procedures used to clear the turbines of fouling. Power losses are discussed and measures that can be taken to prevent fouling are described. Measurements made at an installation in Freienstein, Switzerland, are presented and discussed. The report is completed with an appendix containing calculations, details on the Freienstein power plant and the results of interviews made with the ten hydro power installations examined.

  20. ArcHydro global datasets for Hawaii StreamStats

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of a personal geodatabase containing several vector datasets. These datasets may be used with the ArcHydro Tools, developed by ESRI in...

  1. Development of Key Technologies of Large Hydro Unit in HEC

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Introduction to HEC Harbin Electric Machinery Company Limited (HEC) is a pivotal company that produces large electric machinery and accessorial control equipment in China. The hydro units made by HEC have accounted

  2. Investigation of Hydro-Geochemical Characteristics of Groundwater ...

    African Journals Online (AJOL)

    Investigation of Hydro-Geochemical Characteristics of Groundwater In Port Harcourt City, ... Constituents of the heavy metals as shown in this study reveal that, in some ... Microbial analysis of the water samples to determine the presumptive ...

  3. India small hydro funding to foster 110MW

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The India Renewable Energy Development Agency (IREDA) hopes to fund 30 to 40 new small hydro projects, totaling about 110MW, from US$110 million available for development of private sector projects in India's northern and central states. The World Bank approved US$135 million in funding to IREDA, of which US$110 million is to be used to develop private sector small hydro projects in India's northern and central states;

  4. MESL: Proposal for a Non-volatile Cascadable Magneto-Electric Spin Logic

    Science.gov (United States)

    Jaiswal, Akhilesh; Roy, Kaushik

    2017-01-01

    In the quest for novel, scalable and energy-efficient computing technologies, many non-charge based logic devices are being explored. Recent advances in multi-ferroic materials have paved the way for electric field induced low energy and fast switching of nano-magnets using the magneto-electric (ME) effect. In this paper, we propose a voltage driven logic-device based on the ME induced switching of nano-magnets. We further demonstrate that the proposed logic-device, which exhibits decoupled read and write paths, can be used to construct a complete logic family including XNOR, NAND and NOR gates. The proposed logic family shows good scalability with a quadratic dependence of switching energy with respect to the switching voltage. Further, the proposed logic-device has better robustness against the effect of thermal noise as compared to the conventional current driven switching of nano-magnets. A device-to-circuit level coupled simulation framework, including magnetization dynamics and electron transport model, has been developed for analyzing the present proposal. Using our simulation framework, we present energy and delay results for the proposed Magneto-Electric Spin Logic (MESL) gates.

  5. Enhanced magneto-optic activity of magnetite-based ferrofluids subjected to gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Devi, Manasi; Das, Rupali; Mohanta, Dambarudhar; Baruah, Kishor Kumar [Tezpur University, Nanoscience and Soft Matter Laboratory, Department of Physics, PO Napaam, Assam (India); Saha, Abhijit [UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata (India)

    2012-03-15

    We report here the effect of {gamma}-irradiation on the particle size and size distribution dependent spectroscopic and magneto-optic properties of ferrofluids, synthesized by a co-precipitation method. The X-ray diffraction (XRD) study exhibits magnetite (Fe{sub 3}O{sub 4}) phase of the particles while electron microscopic and dynamic light scattering (DLS) studies have predicted particle growth upon {gamma}-irradiation. Further, Fourier transform infrared (FT-IR) spectroscopy studies ensured that no dissociation has occurred due to irradiation effect. As a consequence of magneto-optic behavior reflected in the Faraday rotation (FR) measurement, the Verdet constant increased from a value of 0.64 x 10{sup -2} for the pristine sample to 5.6 x 10{sup -2} deg/Gauss-cm for the sample irradiated with the highest dose (2.635 kGy). The substantial enhancement in the FR is assigned to the improvement in associated chaining effect owing to adequate particle growth where an increased stoichiometry variation of Fe{sup 2+}/Fe{sup 3+} is assured. (orig.)

  6. A new three-dimensional magneto-viscoelastic model for isotropic magnetorheological elastomers

    Science.gov (United States)

    Agirre-Olabide, I.; Lion, A.; Elejabarrieta, M. J.

    2017-03-01

    In this work, a four-parameter fractional derivative viscoelastic model was developed to describe the dynamic shear behaviour of magnetorheological elastomers (MREs) as a function of the matrix, particle content and magnetic field. The material parameters were obtained from experimental data measured with a Physica MCR 501 rheometer from the Anton Paar Company, equipped with a magnetorheological cell. The synthetised isotropic MRE samples were based on room-temperature vulcanising silicone rubber and spherical carbonyl iron powder micro particles as fillers, and seven volumetric particle contents were studied. The influence of particle contents was included in each parameter of the four-parameter fractional derivative model. The dependency of the storage modulus as a function of an external magnetic field (magnetorheological (MR) effect) was studied, and a dipole–dipole interaction model was used. A new three-dimensional magneto-viscoelastic model was developed to couple the viscoelastic model, the particle-matrix interaction and the magneto-induced modulus model, which predicts the influence of the magnetic field and the particle content in the MR effect of isotropic MREs.

  7. MESL: Proposal for a Non-volatile Cascadable Magneto-Electric Spin Logic

    Science.gov (United States)

    Jaiswal, Akhilesh; Roy, Kaushik

    2017-01-01

    In the quest for novel, scalable and energy-efficient computing technologies, many non-charge based logic devices are being explored. Recent advances in multi-ferroic materials have paved the way for electric field induced low energy and fast switching of nano-magnets using the magneto-electric (ME) effect. In this paper, we propose a voltage driven logic-device based on the ME induced switching of nano-magnets. We further demonstrate that the proposed logic-device, which exhibits decoupled read and write paths, can be used to construct a complete logic family including XNOR, NAND and NOR gates. The proposed logic family shows good scalability with a quadratic dependence of switching energy with respect to the switching voltage. Further, the proposed logic-device has better robustness against the effect of thermal noise as compared to the conventional current driven switching of nano-magnets. A device-to-circuit level coupled simulation framework, including magnetization dynamics and electron transport model, has been developed for analyzing the present proposal. Using our simulation framework, we present energy and delay results for the proposed Magneto-Electric Spin Logic (MESL) gates. PMID:28045074

  8. Detection of endogenous magnetic nanoparticles with a tunnelling magneto resistance sensor.

    Science.gov (United States)

    Ionescu, A; Darton, N J; Vyas, K; Llandro, J

    2010-09-28

    The magnetotactic bacterium Magnetospirillum sp. has been cultured and the properties of its endogenous magnetic nanoparticles characterized. Electron-microscopic analyses indicate that the endogenous magnetite nanoparticles in Magnetospirillum sp. are coated with a 3-4 nm thick transparent shell, forming a magnetosome. These magnetite nanoparticles had diameters of 50.9+/-13.3 nm, in good agreement with the diameter of 40.6+/-1.2 nm extracted from magnetometry. Each Magnetospirillum sp. bacterium contained chains of 5-25 magnetosomes. Superconducting quantum interference device magnetometry results indicate that the extrinsic superparamagnetic response of the bacterial solution at room temperature can be attributed to the reversal of the magnetization by physical rotation of the nanoparticles. The intrinsic blocking temperature of a sample of freeze-dried bacteria was estimated to be 282+/-13 K. A tunnelling magneto resistance sensor was used to detect the stray fields of endogenous magnetic nanoparticles in static and quasi-dynamic modes. Based on the tunnelling magneto resistance sensor results, the magnetic moment per bacterium was estimated to be approximately 2.6 x 10(-13) emu. The feasibility of this detection method either as a mass-coverage device or as part of an integrated microfluidic circuit for detection and sorting of magnetosome-containing cells was demonstrated.

  9. Magneto-conductive encryption assisted by third-order nonlinear optical effects in carbon/metal nanohybrids

    Science.gov (United States)

    García-Merino, J. A.; Mercado-Zúñiga, C.; Martínez-González, C. L.; Torres-SanMiguel, C. R.; Vargas-García, J. R.; Torres-Torres, C.

    2017-03-01

    The influence of a magnetic field on electrical conductivity and the third-order nonlinear optical properties exhibited by carbon nanotubes decorated with platinum nanoparticles is reported. The experimental and numerical results of the nonlinear magneto-optics, magneto-conductivity and photo-thermal processes were analyzed. The simultaneous impact of optical absorptive nonlinearities and the magnetic field in the sample allowed us to encrypt information in the electronic signals by designing an exclusive-OR logic gate scheme. The samples were prepared in film form using a spray pyrolysis route and a chemical vapor deposition approach. The characterization of the morphological nature of the multiwall nanotubes was evaluated by transmission electron microscopy and x-ray techniques. A vectorial two-wave mixing method was conducted by using nanosecond pulses at 532 nm in order to estimate the nonlinear optical behavior in the nanohybrid materials explored. An important enhancement in the phonon-band-structured transport from the inclusion of nanoparticles in the nanotubes was numerically calculated. A distinguished modification in the transient dynamics of the photo-thermal transitions and Kerr nonlinearities was pointed out to be due to the metallic nanoparticles incorporated in the sample. An extraordinary evolution of the magneto-conductivity, together with a strong change in the optical Kerr transmittance exposed to the magnetic field in propagation through the nanostructures, was observed.

  10. Micro hydro power for rural electrification in Papua New Guinea

    Energy Technology Data Exchange (ETDEWEB)

    Gafiye, G.D. [Papua New Guinea Univ. of Technology (Papua New Guinea)

    1996-12-31

    About 85 percent of the population of Papua New Guinea live in remote rural areas. The country has, however, the potential for renewable energy resources such as solar, biomass and hydro power. Due to the ruggedness of the country, the majority of the communities have no access to grid electricity to meet their energy requirements. There is a need to have a reliable electricity supply to these areas. This can be met by the use of micro hydro power and solar systems. Micro hydro has been investigated for many of the stations. Solar will be investigated in the case where micro hydro is not possible. Government policy on rural electrification, and the introduction of micro hydro power is discussed. A number of recommendations are made as to the assistance which could be provided to communities so that they can take advantage of the technology. Those organizations which have expertise in micro hydro power should be encouraged to set up offices in Papua New Guinea and undertake activities such as training, construction and local manufacture. (author). 5 refs.

  11. Research on the soft start-up performance of hydro-viscous drive

    Institute of Scientific and Technical Information of China (English)

    WEI Jian-hua(魏建华); CHEN Ning(陈宁)

    2004-01-01

    The principle and structure of hydro-viscous drive(HVD) set is introduced. Through theoretical analysis of the HVD set start-up steadiness, the conclusions were obtained that the non-linearity of the pressure performance curve and dynamic pressure instability of the pilot-operated electro-hydraulic pressure relief valve, which is used for the HVD speed regulating purpose and usually works within micro flow-rate and low oil pressure state, are the main causes of the poor start-up steadiness. So a special speed regulating valve for HVD set is developed, with which the start-up steadiness of HVD set is much improved.

  12. 75 FR 14437 - North Eastern Wisconsin Hydro Inc. (N.E.W. Hydro); Notice of Intent To File License Application...

    Science.gov (United States)

    2010-03-25

    ... Marinette County, Wisconsin. No Federal lands are occupied by the project works or located within the... Division of Hydropower Licensing approved N.E.W. Hydro's request to use the Traditional Licensing Process...

  13. SQUID and magneto-optic investigations of flux turbulence

    DEFF Research Database (Denmark)

    Koblischka, M.R.; Johansen, T.H.; Baziljevich, M.

    2000-01-01

    Instabilities of the critical state ("turbulence") are observed in various high-T-c, single crystals by means of magneto-optic (MO) imaging. Using the same samples as in the MO investigations, we observe for the first time characteristic steps in the magnetic moment measured by means of a SQUID s...

  14. Efficient magneto-optical mode converter on glass

    Science.gov (United States)

    Garayt, Jean Philippe; Parsy, François; Jamon, Damien; Neveu, Sophie; Royer, François; Ghibaudo, Elise; Broquin, Jean-Emmanuel

    2014-03-01

    The integration of magneto-optical materials to realize non-reciprocal functions is still a difficult problem, because classical magneto-optical materials require an annealing temperature as high as 700°C. In this framework, this study shows how it is possible to realize efficient magneto-optical mode converter using the association of a magnetic nanoparticles silica/zirconia composite with an ion-exchanged glass waveguide. Using a sol gel process, a silica/zirconia matrix is doped by magnetic nanoparticles (CoFe2O4) and coated on a glass substrate containing straight channel waveguides made by a silver/sodium ion exchange. The extremities of the guides were previously buried using electric field-assisted burial in order to facilitate light injection. Soft annealing (90°C) and UV treatment, both compatible with the ion exchange process, have been implemented to finalize the magneto-optical film. Depending on the amount of nanoparticles in the composite, on the spatial distribution of the field in the guide and on the modal birefringence of the hybrid structure, the TE-TM conversion varies from several degrees to several tens of degrees.

  15. Progress in magneto-encephalography; Les progres de la magnetoencephalographie

    Energy Technology Data Exchange (ETDEWEB)

    Dehaene, St. [CEA Saclay, Institut d' Imagerie Biomedicale - NeuroSpin, Dir. des Sciences du Vivant, 91 - Gif-sur-Yvette (France); Fermon, C. [CEA Saclay, Direction des Sciences de la Matiere, 91 - Gif-sur-Yvette (France)

    2008-07-01

    Researchers looking for a higher temporal resolution of cognitive functions are turning to magneto-encephalography (MEG) as an extension to MRI. Progress made in MEG imaging, especially in terms of the sensors employed, is opening up a broader range of applications. (authors)

  16. Magneto-Coulomb effect in spin-valve devices

    NARCIS (Netherlands)

    van der Molen, SJ; Tombros, N; van Wees, BJ

    2006-01-01

    We discuss the influence of the magneto-Coulomb effect (MCE) on the magnetoconductance of spin-valve devices. We show that the MCE can induce magnetoconductances of several percent or more, depending on the strength of the Coulomb blockade. Furthermore, the MCE-induced magnetoconductance changes sig

  17. A New Approach for Magneto-Static Hysteresis Behavioral Modeling

    DEFF Research Database (Denmark)

    Astorino, Antonio; Swaminathan, Madhavan; Antonini, Giulio

    2016-01-01

    In this paper, a new behavioral modeling approach for magneto-static hysteresis is presented. Many accurate models are currently available, but none of them seems to be able to correctly reproduce all the possible B-H paths with low computational cost. By contrast, the approach proposed...... achieved when comparing the measured and simulated results....

  18. Fail-safe design and analysis for the guide vane of a hydro turbine

    Directory of Open Access Journals (Sweden)

    Bentang Arief Budiman

    2016-07-01

    Full Text Available A design for the fail-safe mechanism of a guide vane in a Francis-type hydro turbine is proposed and analyzed. The mechanism that is based on a shear pin as a sacrificial component was designed to remain simple. Unlike the requirements of conventional designs, a shear pin must be able to withstand static and dynamic loads but must fail under a certain overload that could damage a guide vane. An accurate load determination and selection of the shear pin material were demonstrated. The static load for various opening angles of the guide vane were calculated using the computational fluid dynamics Fluent and finite element method Ansys programs. Furthermore, simulations for overload and dynamic load due to the waterhammer phenomenon were also conducted. The results of load calculations were used to select an appropriate shear pin material. Quasi-static shear tests were performed for two shear pins of aluminum alloy Al2024 subjected to different aging treatments (i.e. artificial and natural aging. The test results indicated that the Al2024 treated by natural aging is an appropriate material for a shear pin designed to function as a fail-safe mechanism for the guide vanes of a Francis-type hydro turbine.

  19. A study of the dynamic range electron-thermomagnetic recording

    Directory of Open Access Journals (Sweden)

    I. A. Andrakovskaya

    1987-12-01

    Full Text Available The dynamic range of electron-beam thermal magnetic recording medium moving hromdioksidnom. The main conditions ensuring the maximum effect modulation domain structure of the magneto-optical transducer.

  20. Action principles for hydro- and thermo-dynamics

    Science.gov (United States)

    Fronsdal, Christian

    2017-03-01

    A Hamiltonian formulation of hydrodynamics is well known for the case of purely irrotational flows and it now exists in a more general case as well. The minimal extension of the action principle is obtained from two axioms: 1. That the number of independent degrees of freedom be 4, as in standard hydrodynamics. 2. That the equation of continuity must be one of the Euler-Lagrange equations, and that it allows for vorticity. Applications include: 1. Couette flow with a new criterion for the breakdown of laminar motion. 2. A rotating source for Einstein's equation that respects the Bianchi identity. 3. A new approach to the electromagnetism of fluids. 4. A rigorous virial theorem for fluids. 5. A critique of the current state of the theory of atmospheres.

  1. Hydro-meteorological risk reduction through land restoration in Rangárvellir, Iceland - an overview of the HydroResilience project

    Science.gov (United States)

    Finger, David C.; Pétursdóttir, Þórunn; Halldórsson, Guðmundur

    2017-04-01

    Ecosystems that are in equilibrium provide vital resources to local inhabitants, including protection from naturally occurring disasters. Natural vegetation cover has been optimized over many years to retain a maximum of rainfall runoff by increasing the field capacity (FC) of the soil cover, securing water availability during droughts and reducing the flood risk during heavy precipitation events. In this presentation we will present the HydroResilience project, which will assess the effects of ecosystem restoration on the runoff dynamics of rainfall water in Rangárvellir, a restoration area in southern Iceland. The Rangárvellir area presents ideal conditions for such investigations. Dramatic deforestation during the last millennium and year round livestock grazing along with devastating ash depositions during volcanic eruptions and a harsh sub-polar oceanic climate have led to severe degradation in Rangárvellir. Since the beginning of the 20th century diverse restoration measures have been implemented making Rangárvellir an ideal case study to investigate the effects of restoration on hydro-meteorological risk reduction. In this project we will assess and quantify the evolution of water resources in Rangárvellir by assessing the runoff dynamics in the main rivers of Rangárvellir under four main scenarios: i) present conditions, ii) degraded conditions as was the case 100 years ago, iii) under hypothetical fully restored ecosystems and, finally, iv) under conditions of a scenario developed in collaboration with local stakeholder groups to optimize socio-ecological benefits. For this purpose the dynamics of the relevant hydrological processes in the area (incl. river runoff, ground water table, snow cover duration, and soil moisture dynamics) will be reconstructed using hydrological models to run the above mentioned scenarios. The scientific findings and conclusion of this project will generate valuable insights on the effects of land restoration on hydro

  2. Reliable and cost effective micro hydro power

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-03-01

    A 14 kW hydroelectric power plant in British Columbia that generates enough power to run a small farm was described. It was developed as an alternative to bringing in power from BC Hydro, which would have cost about the same initially, but would also have entailed about $300 per month of utility bills. The system operates at a fraction of its capacity at practically no operating cost and the capital outlay will have been recovered in six to seven years. The system uses a Lima generator directly coupled to a pelton turbine. Some 1,400 feet of five inch PCV pipe running down a hillside provides 136 psi of static pressure. The pressurized water in the pipeline squirts through a nozzle and the jet of water strikes the buckets of the pelton turbine. The energy in the water is transferred to the turbine and provides the shaft power to drive the generator. Two electrically heated dwellings, a workshop and a barn containing 300 pigs are supplied by the power plant.

  3. Unit-sizing of hydro power plant

    Science.gov (United States)

    Maruzewski, P.; Rogeaux, C.; Laurier, P.

    2012-11-01

    In developing countries with great and unexploited renewable energy potential, Governments can exploit local resources for electricity supply, substantial energy savings and sustainable socio-economic development of these own countries. The decision-making process regarding the choice of renewable energy sources for energy supply in these countries is multidimensional, made up of a number of aspects at different levels such as economic, technical, environmental, and social. Therefore, reaching clear and unambiguous solutions may be very difficult. It is from this difficulty that the need arises to develop a tool for the design of hydro energy sources for electricity. The work involved in seeking a compromise solution requires an adequate technical assessment based on multiple criteria methods. One of the criteria is the assessment of the appropriate size of the hydropower plant. This paper presents the state-of-art of preliminary sizing of hydropower plant for the given renewable energy potential. The main step consists of carefully selecting and sizing the innovative hydraulic units based upon the suitability of the flow and head range. Since the flow and head data have now been confirmed, the potential annual energy generation can be properly assessed.

  4. Minoan and Etruscan Hydro-Technologies

    Directory of Open Access Journals (Sweden)

    Pietro Laureano

    2013-07-01

    Full Text Available The aim of this study is to present water and wastewater technologies used during the Minoan (ca. 3200–1100 BC and Etruscan (ca. 800–100 BC civilizations. The basic technologies considered are: water harvesting and distribution systems, cisterns, groundwater and wells as well as drainage and sewerage systems. Minoan water collection and distribution systems primarily consisted of cisterns and pipes. The Etruscans’ hydro-technology also consisted of cisterns and pipes but was developed for urban areas and included distinctions between public and private water use. The long-term sustainability of Minoan cisterns is evidenced by the fact that this technique is still practiced today in rural areas of Crete. In addition to cisterns, wells have been used in Crete since Neolithic times, and enjoyed wide-spread use during the Etruscan era. All the Minoan palaces applied strategies to dispose of water and wastewater with open terracotta or stone masonry-conduits, and stone masonry sewers; while, the drainage and sewerage systems developed by the Etruscans were based both on a coordinated and comprehensive planning of the slopes of drainage channels on the sides of streets as well as on a massive use of drainage tunnels.

  5. Hydro-Balanced Stuffing Box field test

    Energy Technology Data Exchange (ETDEWEB)

    Giangiacomo, L.A.

    1999-05-28

    The Hydro-Balanced Stuffing Box is a seal assembly for polished rod pumping installations commonly used in oil and gas pumping well installations to contain produced well fluids. The improved stuffing box was developed and patented by Harold H. Palmour of The Palmour Group of Livingston, TX. The stuffing box is designed to reduce the incidence of seal leakage and to utilize an environmentally safe fluid, so that if there is any leakage, environmental damage is reduced or eliminated. The unit was tested on two wells at the Rocky Mountain Oilfield Testing Center. During the test period, the performance of the stuffing box was measured by monitoring the pressure on the tubing and the inner chamber with a Barton Two-pen recorder. The amount of safe fluid consumed, fluid leakage at the top of the stuffing box, pressure supplied from the nitrogen bottle, ambient temperature, and polish rod temperature was recorded. The stuffing box is capable of providing a better seal between well fluids an d the environment than conventional stuffing boxes. It allows the polished rod to operate cooler and with lubrication, extending the life of the packing elements, and reducing the amount of attention required to prevent leakage.

  6. Linear and nonlinear magneto-optics of ferritin.

    Science.gov (United States)

    Pankowska, M; Dobek, A

    2009-07-07

    Measurements of Rayleigh light scattering and Cotton-Mouton (CM) effect are carried out at room temperature for 100 mM NaCl solutions of apoferritin/ferritin loaded with 0, 90, 100, 500, 700, and 1500 Fe atoms/molecule. Because of the spherical shape, ferritin macromolecule should not manifest magnetic anisotropy; however, in solution it shows the induced magnetic birefringence (CM effect) and changes in intensity of the scattered light components. The newly obtained data support the previously reported conclusions indicating that the deformation of linear optical polarizability induced in the ferritin by a magnetic field and the orientation of the induced magnetic dipole moment by this field are the main sources of the magneto-optical phenomena observed. Nevertheless, it is also found that the orientation of the permanent magnetic dipole moment contributes to both effects. The magnetic field induced changes in the light scattering and the CM effect theoretically depend on the linear magneto-optical polarizability, chi, on the nonlinear magneto-optical polarizability, eta, and square of the permanent magnetic dipole moment value of the macromolecule, mu(2). On the basis of the theory describing both effects as well as the experimental data, the values of the anisotropy of linear magneto-optical polarizabilities components, the values of the linear optical polarizability and its anisotropy, nonlinear magneto-optical polarizability and its anisotropy, are estimated. Also the magnetic dipole moment of the ferritin macromolecule is found. Interestingly, not all iron atoms in the ferritin are indicated to be in the superparamagnetic state, some of them occur in the diamagnetic form.

  7. Analysis, Predictive Modeling and Hoisted Object Impact Control in Hydro-cylinder Stage- Switching

    Directory of Open Access Journals (Sweden)

    S. V. Kobyzev

    2016-01-01

    Full Text Available The paper considers a problem of dynamic impact of hoisting mechanisms, which are based on the multistage hydro-cylinders, on the hoisted object. Hydro-cylinders have high specific characteristics, but there are also some drawbacks. One of them is an impact at the beginning and at the end of hoist and in switching the stages. And in case of switching the stages under certain conditions the impact in nature can be a high impact impulse. The paper explores the impacts at the beginning of hoist and when switching the stages.Numerical modeling is assumed to be a method of study. To build a mathematical model the following factors have been considered: geometrical cylinder parameters, hydraulic liquid compressibility, and friction between cylinder elements. Elasticity of ground, elasticity of rod, and elasticity of cylinder walls have been ignored.The modeling results allowed us to reveal a hydraulic nature of the stage-switching impact, introduce a formula to estimate the impact impulse value, show the friction effect on the impact impulse value and give a proposal to use a counter-pressure chamber to eliminate the stage-switching impact. An expression for the optimal counter-pressure is presented.The results obtained can find application in designing the new and upgrading the existing hoisting multistage hydro-cylinder mechanisms to increase a hoisting speed and simultaneously eliminate the impact on hoisted object.Compared to existing papers in the field concerned, this one concentrates on revealing a specific hydraulic nature of the stage-switching impact, without regard to dynamics and elasticity of the hoisting mechanism parts other than the cylinder itself.The achieved results find confirmation when compared to the numerical and field data published by other authors.

  8. Overview of Hydrometeorologic Forecasting Procedures at BC Hydro

    Science.gov (United States)

    McCollor, D.

    2004-12-01

    Energy utility companies must balance production from limited sources with increasing demand from industrial, business, and residential consumers. The utility planning process requires a balanced, efficient, and effective distribution of energy from source to consumer. Therefore utility planners must consider the impact of weather on energy production and consumption. Hydro-electric companies should be particularly tuned to weather because their source of energy is water, and water supply depends on precipitation. BC Hydro operates as the largest hydro-electric company in western Canada, managing over 30 reservoirs within the province of British Columbia, and generating electricity for 1.6 million people. BC Hydro relies on weather forecasts of watershed precipitation and temperature to drive hydrologic reservoir inflow models and of urban temperatures to meet energy demand requirements. Operations and planning specialists in the company rely on current, value-added weather forecasts for extreme high-inflow events, daily reservoir operations planning, and long-term water resource management. Weather plays a dominant role for BC Hydro financial planners in terms of sensitive economic responses. For example, a two percent change in hydropower generation, due in large part to annual precipitation patterns, results in an annual net change of \\50 million in earnings. A five percent change in temperature produces a \\5 million change in yearly earnings. On a daily basis, significant precipitation events or temperature extremes involve potential profit/loss decisions in the tens of thousands of dollars worth of power generation. These factors are in addition to environmental and societal costs that must be considered equally as part of a triple bottom line reporting structure. BC Hydro water resource managers require improved meteorological information from recent advancements in numerical weather prediction. At BC Hydro, methods of providing meteorological forecast data

  9. Dynamic models for magnetospheric oscillations on the minute scale

    Science.gov (United States)

    Sato, H.; Pecseli, H.; Børve, S.; Trulsen, J.

    2012-12-01

    Sudden pulses in the model solar wind sets the Earth's magnetosphere into damped oscillatory motions. Oscillation periods on the order of 5-10 min have been observed by instrumented spacecrafts. A simple model is capable of explaining the basic properties of these oscillations and give scaling laws for their characteristics in terms of the parameters of the problem, such as the Solar wind momentum density. The period of the oscillations, their damping and anharmonic nature are accounted for.The model has no free adjustable numerical parameters and can be seen as an effort to predict some dynamic properties of the magnetosphere on the basis of measurable steady state characteristics. A simple test of the model is found by comparing its prediction of the Earth-Magnetopause distance with observed values. The results agree well with observations. The analysis is supported by numerical simulations solving the Magneto-Hydro-Dynamic (MHD) equations in two spatial dimensions, where we let a solar wind interact with a magnetic dipole representing a magnetized Earth. Two tilt-angles of the magnetic dipole axis were considered. We observe the formation of a magnetosheath, with the magnetopause at a distance corresponding well to the analytical results. The analytical model seem to be robust, and gives good qualitative agreement with the numerical simulations for a range of parameters, also concerning oscillation periods and damping times for cases where the dynamic response to perturbations are considered. The analysis allows also for predicting the magnetic field perturbations detected on Earth due to changes in the magnetosheath current. In order to improve the model we study a conformal mapping that brings the shape of the magnetosheath model closer to observations.

  10. Magneto-induced Line Broadening of Magneto-sensitive Lines in Solar Magnetized Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Zhong-Quan Qu; Shuai Wang; Cheng-Lin Xu; Xiao-Yu Zhang; Ming-Guo Sun; Chun-Lan Jin

    2005-01-01

    We analyze the spectral line broadening of those magneto-sensitive lines in solar magnetized atmospheres. The broadening at the line wings is due to the increase of the effective width of energy levels involved in Zeeman splitting,and the broadening at the line core also originated in Zeeman splitting under the condition that the Zeeman components are mixed. Therefore, the magnetoinduced or Zeeman broadening take effects on the whole line. The observed Stokes parameter data in a sunspot and outside it acquired by Solar Stokes Spectrum Telescope (S3T) are analyzed for the demonstration of this mechanism, and the Zeeman broadening rates are calculated for FeI 6302.5 under some assumptions.Our result shows that the broadening is increased as the magnetic field strength becomes stronger, but the rate of increase at the line core is decreased as the field strength increases, while the rate at the wing does not show such an obvious regularity. The broadening is more effective in the line core than in the wings.

  11. Assessing Hydro-Ecological Vulnerability from Space

    Science.gov (United States)

    Stampoulis, D.; Andreadis, K.; Granger, S. L.; Fisher, J. B.; Turk, F. J.; Behrangi, A.; Das, N. N.; Ines, A.

    2015-12-01

    The main driver of economic growth in East Africa is agriculture. However, climate change and the resulting intensification of the hydrologic cycle will increase water limitation in this already drought-burdened region, and the challenge of ensuring food security is bound to become critical. Efforts must, therefore, be made to develop appropriate adaptation strategies for agriculture in such regions. Assessing and predicting ecosystem responses to global environmental change can advance management and decision support systems that would improve food security and economic development. The current study uses a plethora of multi-year remote sensing earth observations to study the hydro-ecological vulnerability of the various ecosystems in the water-stressed East African region to droughts. More specifically, we assess the hydrologic sensitivity and resilience of soil moisture and vegetation water content (derived from NRL's WindSat radiometer), during dry spells, for different dry-period durations, and for various vegetation categories. Spatiotemporal patterns and characteristics of the response of the two aforementioned variables to sustained precipitation deficits (derived from TRMM 3B42 V7), as well as their persistence in maintaining their stability are identified. We also assess changes, in space and time, in the normalized radar surface-backscattering cross-sections from NASA's QuikSCAT Scatterometer, to obtain information on the vegetation regimes, as well as changes in vegetation phenometrics using the enhanced vegetation index (EVI) derived from MODIS. Quantifying the response and characterizing the resilience of the two aforementioned major hydrological attributes using various remote sensing techniques that complement each other, can provide critical insight into the region's vulnerability and adaptive capacity with respect to rainfall variability.

  12. Ab initio calculation of the optical and magneto-optical properties of moderately correlated magnetic solids

    Energy Technology Data Exchange (ETDEWEB)

    Perlov, A. E-mail: alexander.perlov@cup.uni-muenchen.de; Chadov, S.; Ebert, H.; Chioncel, L.; Lichtenstein, A.I.; Katsnelson, M.I

    2004-05-01

    An approach for the calculation of the optical and magneto-optical properties of solids based on the one-particle Green function is introduced in the framework of the linear muffin-tin orbital (LMTO) method. The approach keeps all advantages of the more accurate Korringa-Kohn-Rostoker (KKR) scheme as the possibility to account for many-body effects in terms of the non-local energy-dependent self-energy but is numerically much more efficient. In particular an incorporation of the single-site self-energy coming from the dynamical mean-field theory (DMFT) is implemented. An application of the approach to bulk Ni and Fe showed rather good agreement with the experimental data, in contrast with the results of standard local spin density approximation (LSDA) computations.

  13. Electroweak interactions between intense neutrino beams and dense electron-positron magneto-plasmas

    CERN Document Server

    Tsintsadze, N L; Stenflo, L

    2003-01-01

    The electroweak coupling between intense neutrino beams and strongly degenerate relativistic dense electron-positron magneto-plasmas is considered. The intense neutrino bursts interact with the plasma due to the weak Fermi interaction force, and their dynamics is governed by a kinetic equation. Our objective here is to develop a kinetic equation for a degenerate neutrino gas and to use that equation to derive relativistic magnetohydrodynamic equations. The latter are useful for studying numerous collective processes when intense neutrino beams nonlinearly interact with degenerate, relativistic, dense electron-positron plasmas in strong magnetic fields. If the number densities of the plasma particles are of the order of 10 sup 3 sup 3 cm sup - sup 3 , the pair plasma becomes ultra-relativistic, which strongly affects the potential energy of the weak Fermi interaction. The new system of equations allows several neutrino-driven streaming instabilities involving new types of relativistic Alfven-like waves, The re...

  14. An Analytical Study of Fire Out of Battery Using Magneto Rheological Dampers

    Directory of Open Access Journals (Sweden)

    Mehdi Ahmadian

    2002-01-01

    Full Text Available The application of magneto rheological dampers for controlling the dynamics of a fire out-of-battery recoil system is examined, using a dynamic simulation of a 105mm cannon. Upon providing a brief background on MR dampers and fire out-of-battery dynamics, we will describe the simulation model, along with some of the results obtained from the model. The simulation results show that although conventional hydraulic recoil dampers can be designed and tuned to control fire out-of-battery dynamics as effectively as MR dampers, they are not able to perform well when firing faults are encountered. The results show that MR dampers are able to adapt to the firing faults such as pre-fire, hang-fire, and misfire and provide "soft recoil" under all firing conditions. The inability of conventional hydraulic dampers to adapt to the firing faults can yield recoil dynamics that seriously jeopardize the performance of the gun. Therefore, the results presented here show that MR dampers may provide an enabling technology in achieving fire out-of-battery under all firing conditions.

  15. Hydro-dissection - A simple Solution in Difficult Laparoscopic Cholecystectomy.

    Science.gov (United States)

    Lubna, H; Masoom, M R

    2015-07-01

    This Quasi-experimental study was done to assess the effectiveness of hydro-dissection in difficult laparoscopic cholecystectomies in Hamdard University Hospital, Karachi, Pakistan, from April 2012 to March 2014. All consecutive patients who presented with cholelithiasis and planned for laparoscopic cholecystectomy were enrolled in this study. Per-operatively the degree of difficulty of the operation was assessed by Cuschieri's scale after grading; Grade II, III and IV cholecystectomies were included in this study. Hydro dissection with saline jet through 5mm simple irrigation and suction probe was used, Operative findings and the total number of patients, in whom anatomy of calot's triangle was clearly displayed with hydro-dissection, was recorded. A total 55 patients were included in the study after assessing the degree of difficulty per operatively by Cuschieri Scale. Thirty one (31) patients were in Group II, 22 in Group III and 02 were included in group IV of Cuschieri scale in which hydro-dissection was used. This method cleared the obscure anatomy in all patients in Group II but in 3 patients of Group III, dense adhesions required sharp dissection to clear the operative field. Two patients, in whom conversion was required, were grouped in Cuschieri's scale IV. Methods of dissection in difficult cholecystectomies are of paramount importance to avoid iatrogenic injuries. Hydro-dissection using suction irrigation probe is a safe and effective technique to clear the difficult anatomy.

  16. Semi-active sliding mode control of vehicle suspension with magneto-rheological damper

    Science.gov (United States)

    Zhang, Hailong; Wang, Enrong; Zhang, Ning; Min, Fuhong; Subash, Rakheja; Su, Chunyi

    2015-01-01

    The vehicle semi-active suspension with magneto-rheological damper(MRD) has been a hot topic since this decade, in which the robust control synthesis considering load variation is a challenging task. In this paper, a new semi-active controller based upon the inverse model and sliding mode control (SMC) strategies is proposed for the quarter-vehicle suspension with the magneto-rheological (MR) damper, wherein an ideal skyhook suspension is employed as the control reference model and the vehicle sprung mass is considered as an uncertain parameter. According to the asymptotical stability of SMC, the dynamic errors between the plant and reference systems are used to derive the control damping force acquired by the MR quarter-vehicle suspension system. The proposed modified Bouc-wen hysteretic force-velocity ( F- v) model and its inverse model of MR damper, as well as the proposed continuous modulation (CM) filtering algorithm without phase shift are employed to convert the control damping force into the direct drive current of the MR damper. Moreover, the proposed semi-active sliding mode controller (SSMC)-based MR quarter-vehicle suspension is systematically evaluated through comparing the time and frequency domain responses of the sprung and unsprung mass displacement accelerations, suspension travel and the tire dynamic force with those of the passive quarter-vehicle suspension, under three kinds of varied amplitude harmonic, rounded pulse and real-road measured random excitations. The evaluation results illustrate that the proposed SSMC can greatly suppress the vehicle suspension vibration due to uncertainty of the load, and thus improve the ride comfort and handling safety. The study establishes a solid theoretical foundation as the universal control scheme for the adaptive semi-active control of the MR full-vehicle suspension decoupled into four MR quarter-vehicle sub-suspension systems.

  17. Semi-active Sliding Mode Control of Vehicle Suspension with Magneto-rheological Damper

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hailong; WANG Enrong; ZHANG Ning; MIN Fuhong; SUBASH Rakheja; SU Chunyi

    2015-01-01

    The vehicle semi-active suspension with magneto-rheological damper(MRD) has been a hot topic since this decade, in which the robust control synthesis considering load variation is a challenging task. In this paper, a new semi-active controller based upon the inverse model and sliding mode control (SMC) strategies is proposed for the quarter-vehicle suspension with the magneto-rheological (MR) damper, wherein an ideal skyhook suspension is employed as the control reference model and the vehicle sprung mass is considered as an uncertain parameter. According to the asymptotical stability of SMC, the dynamic errors between the plant and reference systems are used to derive the control damping force acquired by the MR quarter-vehicle suspension system. The proposed modified Bouc-wen hysteretic force-velocity (F-v) model and its inverse model of MR damper, as well as the proposed continuous modulation (CM) filtering algorithm without phase shift are employed to convert the control damping force into the direct drive current of the MR damper. Moreover, the proposed semi-active sliding mode controller (SSMC)-based MR quarter-vehicle suspension is systematically evaluated through comparing the time and frequency domain responses of the sprung and unsprung mass displacement accelerations, suspension travel and the tire dynamic force with those of the passive quarter-vehicle suspension, under three kinds of varied amplitude harmonic, rounded pulse and real-road measured random excitations. The evaluation results illustrate that the proposed SSMC can greatly suppress the vehicle suspension vibration due to uncertainty of the load, and thus improve the ride comfort and handling safety. The study establishes a solid theoretical foundation as the universal control scheme for the adaptive semi-active control of the MR full-vehicle suspension decoupled into four MR quarter-vehicle sub-suspension systems.

  18. Microwave-mediated magneto-optical trap for polar molecules

    Science.gov (United States)

    Dizhou, Xie; Wenhao, Bu; Bo, Yan

    2016-05-01

    Realizing a molecular magneto-optical trap has been a dream for cold molecular physicists for a long time. However, due to the complex energy levels and the small effective Lande g-factor of the excited states, the traditional magneto-optical trap (MOT) scheme does not work very well for polar molecules. One way to overcome this problem is the switching MOT, which requires very fast switching of both the magnetic field and the laser polarizations. Switching laser polarizations is relatively easy, but fast switching of the magnetic field is experimentally challenging. Here we propose an alternative approach, the microwave-mediated MOT, which requires a slight change of the current experimental setup to solve the problem. We calculate the MOT force and compare it with the traditional MOT and the switching MOT scheme. The results show that we can operate a good MOT with this simple setup. Project supported by the Fundamental Research Funds for the Central Universities of China.

  19. Ghost imaging protocol for magneto-optical applications

    CERN Document Server

    Meda, A; Avella, A; Berchera, I Ruo; Degiovanni, I P; Magni, A; Genovese, M

    2015-01-01

    We develop a new approach in magneto-optical imaging (MOI), applying for the first time a ghost imaging (GI) protocol to perform Faraday microscopy. MOI is one of the most exploited technique for the study of magnetic properties of a material, through Weiss domains form, distribution and dimension analysis. Nevertheless, a lack of imaging of domains in some extreme conditions as cryogenic temperatures or high magnetic fields application is present due to the difficulties related to the imaging setup construction limitation. Here we present a technique that separates the imaging optical path to the one illuminating the object. The technique is based on thermal light GI and exploits correlations between light beams. GI is applied to the Faraday magneto-optical observation of magnetic domains of an Yttrium Iron Garnet (YIG) sample.

  20. Wave propagation in a magneto-electro- elastic plate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The wave propagation in a magneto-electro-elastic plate was studied. Some new characteristics were discovered: the guided waves are classified in the forms of the Quasi-P, Quasi-SV and Quasi-SH waves and arranged by the standing wavenumber; there are many patterns for the physical property of the magneto-electro-elastic dielectric medium influencing the stress wave propagation. We proposed a self-adjoint method, by which the guided-wave restriction condition was derived. After the corresponding orthogonal sets were found, the analytic dispersion equa-tion was obtained. In the end, an example was presented. The dispersive spectrum, the group velocity curved face and the steady-state response curve of a mag-neto-electro-elastic plate were plotted. Then the wave propagations affected by the induced electric and magnetic fields were analyzed.

  1. Linear and nonlinear magneto-optical properties of monolayer phosphorene

    Science.gov (United States)

    Nguyen, Chuong V.; Ngoc Hieu, Nguyen; Duque, C. A.; Quoc Khoa, Doan; Van Hieu, Nguyen; Van Tung, Luong; Vinh Phuc, Huynh

    2017-01-01

    We theoretically study the magneto-optical properties of monolayer phosphorene under a perpendicular magnetic field. We evaluate linear, third-order nonlinear, and total absorption coefficients and relative refractive index changes as functions of the photon energy and the magnetic field, and show that they are strongly influenced by the magnetic field. The magneto-optical absorption coefficients and relative refractive index changes appear in two different regimes: the microwave to THz and the visible frequency. The amplitude of intra-band transition peaks is larger than that of the inter-band transitions. The resonant peaks are blue-shifted with the magnetic field. Our results demonstrate the potential of monolayer phosphorene as a new two-dimensional material for applications in nano-electronic and optical devices as a promising alternative to graphene.

  2. Investigation of magneto-induced linear dichroism of magnetic fluid.

    Science.gov (United States)

    Du, Bobo; Yang, Dexing; Bai, Yang; Yuan, Yuan; Mao, Dong; Zhang, Wending; She, Xiaoyang

    2017-01-20

    A fiber-optic component is fabricated with etched fiber coated by magnetic fluid (MF) for its evanescent field to be modulated by the MF. The magneto-induced linear dichroism of the MF is investigated under different temperatures with the component. The experimental results show that the MF possesses weak linear dichroism (maximum of 2.37% at 25°C) caused by its sparse magneto-induced chains. Considering the relationships between the linear dichroisms and temperature, there is a transition point of magnetic field at ∼4  mT. Up to ∼4  mT, the linear dichroisms decrease with the temperature; however, for higher magnetic field strengths, the linear dichroisms increase with the temperature. Interestingly, a small initial linear dichroism (up to 0.255% at 5°C) without magnetic field is also observed.

  3. Time-dependent resonant magneto-optical rotation

    CERN Document Server

    Dziczek, Dariusz

    2015-01-01

    Results of a fairly straightforward experiment on resonant magneto-optical rotation by rubidium-87 atoms revealed strong time-dependence of the polarization plane of light emerging from atomic vapors following a sudden irradiation with a laser beam. The rotation of the plane appears as a not direct consequence of the influence of the magnetic field on atoms. Reported measurements conducted using a vapor cell without any buffer gas or an anti-relaxation wall coating show that transmitted light has initially the same (linear) polarization as the incident one. Rotation of the polarization plane caused by an axial magnetic field develops in time scales similar to the pace of establishing the optical pumping/relaxation equilibrium in the atomic ensemble. The traditional passive Faraday rotation picture providing working description for the resonant magneto-optical effects in steady-state conditions does not explain the observed sequence of evolution of the polarization. The picture has to be augmented with analysi...

  4. Faraday effect in hybrid magneto-plasmonic photonic crystals.

    Science.gov (United States)

    Caballero, B; García-Martín, A; Cuevas, J C

    2015-08-24

    We present a theoretical study of the Faraday effect in hybrid magneto-plasmonic crystals that consist of Au-Co-Au perforated membranes with a periodic array of sub-wavelength holes. We show that in these hybrid systems the interplay between the extraordinary optical transmission and the magneto-optical activity leads to a resonant enhancement of the Faraday rotation, as compared to purely ferromagnetic membranes. In particular, we determine the geometrical parameters for which this enhancement is optimized and show that the inclusion of a noble metal like Au dramatically increases the Faraday rotation over a broad bandwidth. Moreover, we show that the analysis of the Faraday rotation in these periodically perforated membranes provides a further insight into the origin of the extraordinary optical transmission.

  5. [Hydro-Quebec]: Financial profile, 1998--2001

    Energy Technology Data Exchange (ETDEWEB)

    1999-01-01

    Financial information in this publication includes some retrospective data back as far as 1994 as well as some forecasts to 2001. Information is provided on Hydro-Quebec operation (such as electricity sold, numbers of accounts, and installed capacity), comparative data from other North American electric utilities, world electricity prices, Hydro-Quebec rate increases, provincial economic parameters, Hydro-Quebec gross investment, income, revenue, electricity sales outside Quebec, expenditure, financial expenses, credit ratings and financial ratios, needs and sources of financing, debt by repayment currency, interest rates, comparative average cost of debt, average maturity of debt, total debt, and financing programs. Management discussion is also included with respect to the utility's economic performance, system reliability, and integrated management of business risks.

  6. Micro-hydro power: reviewing an old concept

    Energy Technology Data Exchange (ETDEWEB)

    Alward, R.; Eisenbart, S.; Volkman, J.

    1979-01-01

    This informaion package has been prepared to respond to an increasing number of requests for information on micro-hydro systems. It contains a resource directory, which is an attempt to put the reader in contact with the literature, plans, people, and companies appropriate to needs. On a world-wide basis, small-scale, environmentally benign, mechanical, and electrical hydropower systems are common. These are the systems for individual homes, farm, and shop use and generally have power outputs less than 100 kW. For convenience in terminology, this scale of hydro power is referred to as micro-hydro. A decision tree is first presented followed by information on determining the suitability of th site, equipment, economics, sources for financial assistance, regulatory conflicts, cautions and suggestions for the Do-It-Yourselfer, and the Self-Installer, manufacturers and suppliers, and sources of professional services. An annotated bibliography of 16 references is provided. (MCW)

  7. Characteristics on Hydro-mechanical Transmission in Power Shift Process

    Institute of Scientific and Technical Information of China (English)

    HU Jibin; WEI Chao; YUAN Shihua; JING Chongbo

    2009-01-01

    To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed.The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can't be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

  8. Massive Quiescent Cores in Orion: Dichotomy in the Dynamical Status of Cores

    Science.gov (United States)

    Velusamy, Thangasamy; Goldsmith, P. F.; Li, D.; Langer, W. D.; Pineda, J. L.; Peng, R.

    2009-01-01

    To study the evolution of high mass cores we have searched for evidence of collapse motions in a large sample of starless cores in the Orion molecular cloud. We used the Caltech Submillimeter Observatory telescope to obtain spectra of the optically thin (H13CO+) and optically thick (HCO+) high density tracer molecules in 27 cores with masses > 1 MO. The red- and blue-asymmetries seen in the line profiles of the optically thick line with respect to the optically thin line indicate that 2/3 of these cores are not static and we interpret these as evidence for inward or outward motions in 19 cores. We present RATRAN radiative transfer models of these cores that support the interpretation of inward and outward motion consistent with the observed spectral asymmetries. Thus we detect infall (inward motions) in 9 cores and outward motions for 10 cores, suggesting a dichotomy in the kinematic state in this sample. This population of massive molecular cloud cores is in general likely to be dynamic, out-of-equilibrium structures, rather than quasi-hydro/magneto-static structures. Our results provide an important observational constraint on the fraction of collapsing (inward motions) versus non-collapsing (re-expanding) cores for comparison with model simulations. This work was performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Research at the Caltech Submillimeter Observatory is supported by NSF grant AST-0229008.

  9. Modelos de un amortiguador magneto-reológico

    OpenAIRE

    Fernández Viveros, Alfonso

    2012-01-01

    El presente proyecto se centra en el estudio de los modelos de un amortiguador de tipo magneto-­‐reológico. Para ello es necesario desarrollar un programa para cada modelo que permita obtener los resultados de las ecuaciones de cada uno de ellos. En concreto los modelos sobre los que se realizan los programas son el modelo de Bouc-­‐Wen...

  10. Magneto-optical trapping of a diatomic molecule

    Science.gov (United States)

    Barry, J. F.; McCarron, D. J.; Norrgard, E. B.; Steinecker, M. H.; Demille, D.

    2014-08-01

    Laser cooling and trapping are central to modern atomic physics. The most used technique in cold-atom physics is the magneto-optical trap (MOT), which combines laser cooling with a restoring force from radiation pressure. For a variety of atomic species, MOTs can capture and cool large numbers of particles to ultracold temperatures (less than ~1 millikelvin) this has enabled advances in areas that range from optical clocks to the study of ultracold collisions, while also serving as the ubiquitous starting point for further cooling into the regime of quantum degeneracy. Magneto-optical trapping of molecules could provide a similarly powerful starting point for the study and manipulation of ultracold molecular gases. The additional degrees of freedom associated with the vibration and rotation of molecules, particularly their permanent electric dipole moments, allow a broad array of applications not possible with ultracold atoms. Spurred by these ideas, a variety of methods has been developed to create ultracold molecules. Temperatures below 1 microkelvin have been demonstrated for diatomic molecules assembled from pre-cooled alkali atoms, but for the wider range of species amenable to direct cooling and trapping, only recently have temperatures below 100 millikelvin been achieved. The complex internal structure of molecules complicates magneto-optical trapping. However, ideas and methods necessary for creating a molecular MOT have been developed recently. Here we demonstrate three-dimensional magneto-optical trapping of a diatomic molecule, strontium monofluoride (SrF), at a temperature of approximately 2.5 millikelvin, the lowest yet achieved by direct cooling of a molecule. This method is a straightforward extension of atomic techniques and is expected to be viable for a significant number of diatomic species. With further development, we anticipate that this technique may be employed in any number of existing and proposed molecular experiments, in applications

  11. An Analysis of the Magneto-Optic Imaging System

    Science.gov (United States)

    Nath, Shridhar

    1996-01-01

    The Magneto-Optic Imaging system is being used for the detection of defects in airframes and other aircraft structures. The system has been successfully applied to detecting surface cracks, but has difficulty in the detection of sub-surface defects such as corrosion. The intent of the grant was to understand the physics of the MOI better, in order to use it effectively for detecting corrosion and for classifying surface defects. Finite element analysis, image classification, and image processing are addressed.

  12. A New Generation of Magneto-Rheological Fluid Dampers

    Science.gov (United States)

    2007-11-02

    active MRF damper. An Instron 8821S servo-hydraulic system is used to provide the input road profile. The actuator of the hydraulic unit is mounted...Presented at 8th International conference on Electrorheological (ER) Fluid and Magneto-rheological (MR) Suspensions, Nice, July 9- 13,2001 9...representing the excitation due to the road profile Instron Hydraulic Actuator Linear Slide System providing the movement of the masses 56 0 0.5 1

  13. Transformation magneto-statics and illusions for magnets

    OpenAIRE

    Fei Sun; Sailing He

    2014-01-01

    Based on the form-invariant of Maxwell’s equations under coordinate transformations, we extend the theoryof transformation optics to transformation magneto-statics, which can design magnets through coordinatetransformations. Some novel DC magnetic field illusions created by magnets (e.g. rescaling magnets,cancelling magnets and overlapping magnets) are designed and verified by numerical simulations. Ourresearch will open a new door to designing magnets and controlling DC magnetic fields. ...

  14. Magneto-Seebeck effect in spin-valve with in-plane thermal gradient

    Directory of Open Access Journals (Sweden)

    S. Jain

    2014-12-01

    Full Text Available We present measurements of magneto-Seebeck effect on a spin valve with in-plane thermal gradient. We measured open circuit voltage and short circuit current by applying a temperature gradient across a spin valve stack, where one of the ferromagnetic layers is pinned. We found a clear hysteresis in these two quantities as a function of magnetic field. From these measurements, the magneto-Seebeck effect was found to be same as magneto-resistance effect.

  15. Magneto-Seebeck effect in spin-valve with in-plane thermal gradient

    Energy Technology Data Exchange (ETDEWEB)

    Jain, S., E-mail: sourabhjain@ee.iitb.ac.in; Bose, A., E-mail: arnabbose@ee.iitb.ac.in; Palkar, V. R., E-mail: palkar@ee.iitb.ac.in; Tulapurkar, A. A., E-mail: ashwin@ee.iitb.ac.in [Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India); Lam, D. D., E-mail: lam@spin.mp.es.osaka-u.ac.jp; Suzuki, Y., E-mail: suzuki-y@mp.es.osaka-u.ac.jp [School of Engineering Science, Division of Materials Physics, Osaka University, D312, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sharma, H., E-mail: himanshusharma@phy.iitb.ac.in; Tomy, C. V., E-mail: tomy@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400 076 (India)

    2014-12-15

    We present measurements of magneto-Seebeck effect on a spin valve with in-plane thermal gradient. We measured open circuit voltage and short circuit current by applying a temperature gradient across a spin valve stack, where one of the ferromagnetic layers is pinned. We found a clear hysteresis in these two quantities as a function of magnetic field. From these measurements, the magneto-Seebeck effect was found to be same as magneto-resistance effect.

  16. Magneto-Optic Fiber Bragg Gratings with Application to High-Resolution Magnetic Field Sensors

    Institute of Scientific and Technical Information of China (English)

    Bao-Jian Wu; Ying Yang; Kun Qiu

    2008-01-01

    Magneto-optic fiber Bragg gratings (MFBG) based on magneto-optic materials have a lot of potential applications for sensing and optical signal processing. The transmission and reflection spectra of guided optical waves in the MFBG are investigated. According to the sensitivity of MFBG spectral lines to the magneto-optic coupling intensity varying with applied magnetic field, a novel magnetic field sensor of high-resolution up to 0.01 nm/(kA/m) is predicted.

  17. Torque model of hydro turbine with inner energy loss characteristics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine.

  18. Street Level Hydrology: An Urban Application of the WRF-Hydro Framework in Denver, Colorado

    Science.gov (United States)

    Read, L.; Hogue, T. S.; Salas, F. R.; Gochis, D.

    2015-12-01

    Urban flood modeling at the watershed scale carries unique challenges in routing complexity, data resolution, social and political issues, and land surface - infrastructure interactions. The ability to accurately trace and predict the flow of water through the urban landscape enables better emergency response management, floodplain mapping, and data for future urban infrastructure planning and development. These services are of growing importance as urban population is expected to continue increasing by 1.84% per year for the next 25 years, increasing the vulnerability of urban regions to damages and loss of life from floods. Although a range of watershed-scale models have been applied in specific urban areas to examine these issues, there is a trend towards national scale hydrologic modeling enabled by supercomputing resources to understand larger system-wide hydrologic impacts and feedbacks. As such it is important to address how urban landscapes can be represented in large scale modeling processes. The current project investigates how coupling terrain and infrastructure routing can improve flow prediction and flooding events over the urban landscape. We utilize the WRF-Hydro modeling framework and a high-resolution terrain routing grid with the goal of compiling standard data needs necessary for fine scale urban modeling and dynamic flood forecasting in the urban setting. The city of Denver is selected as a case study, as it has experienced several large flooding events in the last five years and has an urban annual population growth rate of 1.5%, one of the highest in the U.S. Our work highlights the hydro-informatic challenges associated with linking channel networks and drainage infrastructure in an urban area using the WRF-Hydro modeling framework and high resolution urban models for short-term flood prediction.

  19. Modeling magneto-optical trapping of CaF molecules

    Science.gov (United States)

    Tarbutt, M. R.; Steimle, T. C.

    2015-11-01

    Magneto-optical trapping forces for molecules are far weaker than for alkali-metal atoms because the photon scattering rate is reduced when there are multiple ground states, and because of optical pumping into dark states. The force is further reduced when the upper state has a much smaller Zeeman splitting than the lower state. We use a rate model to estimate the strength of the trapping and damping forces in a magneto-optical trap (MOT) of CaF molecules, using either the A 2Π1 /2-X 2Σ+ transition or the B 2Σ+-X 2Σ+ transition. We identify a mechanism of magneto-optical trapping that arises when, in each beam of the MOT, two laser components with opposite polarizations and different detunings address the same transition. This mechanism produces a strong trapping force even when the upper state has little or no Zeeman splitting. It is the main mechanism responsible for the trapping force when the A 2Π1 /2-X 2Σ+ transition is used.

  20. Improved magneto-optical trapping of a diatomic molecule

    CERN Document Server

    McCarron, D J; Steinecker, M H; DeMille, D

    2014-01-01

    We present experimental results from a new scheme for magneto-optically trapping strontium monofluoride (SrF) molecules, which provides increased confinement compared to our original work. The improved trap employs a new approach to magneto-optical trapping presented by M. Tarbutt, \\emph{arXiv preprint} 1409.0244, which provided insight for the first time into the source of the restoring force in magneto-optical traps (MOTs) where the cycling transition includes dark Zeeman sublevels (known as type-II MOTs). We measure a radial spring constant $20\\times$ greater than in our original work with SrF, comparable to the spring constants reported in atomic type-II MOTs. We achieve a trap lifetime $\\tau_{\\rm{MOT}}=136(2)$~ms, over $2\\times$ longer than originally reported for SrF. Finally, we demonstrate further cooling of the trapped molecules by briefly increasing the trapping lasers' detunings. Our trapping scheme remains a straightforward extension of atomic techniques and marks a step towards the direct product...

  1. Magneto-optical trapping of a diatomic molecule

    CERN Document Server

    Barry, J F; Norrgard, E B; Steinecker, M H; DeMille, D

    2014-01-01

    Laser cooling and trapping are central to modern atomic physics. The workhorse technique in cold-atom physics is the magneto-optical trap (MOT), which combines laser cooling with a restoring force from radiation pressure. For a variety of atomic species, MOTs can capture and cool large numbers of particles to ultracold temperatures (<1 mK); this has enabled the study of a wide range of phenomena from optical clocks to ultracold collisions whilst also serving as the ubiquitous starting point for further cooling into the regime of quantum degeneracy. Magneto-optical trapping of molecules could provide a similarly powerful starting point for the study and manipulation of ultracold molecular gases. Here, we demonstrate three-dimensional magneto-optical trapping of a diatomic molecule, strontium monofluoride (SrF), at a temperature of approximately 2.5 mK. This method is expected to be viable for a significant number of diatomic species. Such chemical diversity is desired for the wide array of existing and prop...

  2. What is the longitudinal magneto-optical Kerr effect?

    Science.gov (United States)

    Ander Arregi, Jon; Riego, Patricia; Berger, Andreas

    2017-01-01

    We explore the commonly used classification scheme for the magneto-optical Kerr effect (MOKE), which essentially utilizes a dual definition based simultaneously on the Cartesian coordinate components of the magnetization vector with respect to the plane of incidence reference frame and specific elements of the reflection matrix, which describes light reflection from a ferromagnetic surface. We find that an unambiguous correspondence in between reflection matrix elements and magnetization components is valid only in special cases, while in more general cases, it leads to inconsistencies due to an intermixing of the presumed separate effects of longitudinal, transverse and polar MOKE. As an example, we investigate in this work both theoretically and experimentally a material that possesses anisotropic magneto-optical properties in accordance with its crystal symmetry. The derived equations, which specifically predict a so-far unknown polarization effect for the transverse magnetization component, are confirmed by detailed experiments on epitaxial hcp Co films. The results indicate that magneto-optical anisotropy causes significant deviations from the commonly employed MOKE data interpretation. Our work addresses the associated anomalies, provides a suitable analysis route for reliable MOKE magnetometry procedures, and proposes a revised MOKE terminology scheme.

  3. Magneto-optical Trapping of a Diatomic Molecule

    Science.gov (United States)

    Demille, Dave

    2014-05-01

    The magneto-optical trap (MOT) is the workhorse technique for atomic physics in the ultracold regime, serving as the starting point in applications from optical clocks to quantum-degenerate gases. Although MOTs have been used with a wide array of atomic species, realization of a molecular MOT was long considered infeasible. In this talk we will describe the first magneto-optical trap for a molecule, strontium monofluoride (SrF). Our MOT produces the coldest trapped sample of directly-cooled molecules to date, with temperature T ~2.5 mK. The SrF MOT is loaded from a cryogenic buffer-gas beam slowed by laser radiation pressure. Images of laser-induced fluorescence allow us to characterize the trap's properties. Although magneto-optical trapping of diatomic molecules is in its infancy, our results indicate that access to the ultracold regime may be possible for several molecular species, with potential applications from quantum simulation to tests of fundamental symmetries to ultracold chemistry.

  4. Improved magneto-optical trapping of a diatomic molecule

    Science.gov (United States)

    Norrgard, Eric; McCarron, Daniel; Steinecker, Matthew; Demille, David

    2015-05-01

    The magneto-optical trap (MOT) is the workhorse technique for atomic physics in the ultracold regime, serving as the starting point in applications from optical clocks to quantum-degenerate gases. Recently, our group demonstrated the first magneto-optical trap for a molecule, strontium monofluoride (SrF). Here, we present experimental results of two variant trapping schemes which improve upon the original work. In the first, recent insights into the origin of the restoring force in Type-II MOTs (rarely used for atoms but requisite for SrF and other candidate molecules) led to a simple change in polarization scheme for the MOT lasers. In the second, states dark to the restoring MOT beams are diabatically transferred to bright states by synchronously reversing the magnetic field gradient and the laser polarization at RF frequencies. Although magneto-optical trapping of diatomic molecules is in its infancy, our results indicate that access to the ultracold regime may be possible for several molecular species, with potential applications from quantum simulation to tests of fundamental symmetries to ultracold chemistry. We acknowledge funding from ARO and ARO (MURI). E.B.N. acknowledges funding from the NSF GRFP.

  5. Modeling magneto-optical trapping of CaF molecules

    CERN Document Server

    Tarbutt, M R

    2015-01-01

    Magneto-optical trapping forces for molecules are far weaker than for alkali atoms because the photon scattering rate is reduced when there are multiple ground states, and because of optical pumping into dark states. The force is further reduced when the upper state has a much smaller Zeeman splitting than the lower state. We use a rate model to estimate the strength of the trapping and damping forces in a magneto-optical trap (MOT) of CaF molecules, using either the A$^{2}\\Pi_{1/2}$ - X$^{2}\\Sigma^{+}$ transition or the B$^{2}\\Sigma^{+}$ - X$^{2}\\Sigma^{+}$ transition. We identify a new mechanism of magneto-optical trapping that arises when, in each beam of the MOT, two laser components with opposite polarizations and different detunings address the same transition. This mechanism produces a strong trapping force even when the upper state has little or no Zeeman splitting. It is the main mechanism responsible for the trapping force when the A$^{2}\\Pi_{1/2}$ - X$^{2}\\Sigma^{+}$ transition is used.

  6. Magneto-optical transport properties of monolayer WSe2

    Science.gov (United States)

    Tahir, M.; Vasilopoulos, P.

    2016-07-01

    The recent experimental realization of a high quality WSe2 leads to the possibility of magneto-optical measurements and the manipulation of the spin and valley degrees of freedom. We study the influence of the very strong spin-orbit coupling and of the anisotropic lifting of the valley pseudospin degeneracy on its magnetotransport properties. The energy spectrum of WSe2 is derived and discussed in the presence of a perpendicular magnetic field B . Correspondingly we evaluate the magneto-optical Hall conductivity and the optical longitudinal conductivity as functions of the frequency, magnetic field, and Fermi energy. They are strongly influenced by the field B and the strong spin splitting. The former exhibits valley polarization and the latter beatings of oscillations. The magneto-optical responses can be tuned in two different regimes: the microwave-to-terahertz regime and the visible-frequency one. The absorption peaks involving the n =0 LL appear in between these two regimes and show a magnetic control of the spin and valley splittings. We also evaluate the power absorption spectrum.

  7. Decision making algorithms for hydro-power plant location

    CERN Document Server

    Majumder, Mrinmoy

    2013-01-01

    The present study has attempted to apply the advantage of neuro-genetic algorithms for optimal decision making in maximum utilization of natural resources. Hydro-power is one of the inexpensive, but a reliable source of alternative energy which is foreseen as the possible answer to the present crisis in the energy sector. However, the major problem related to hydro-energy is its dependency on location. An ideal location can produce maximum energy with minimum loss. Besides, such power-plant also requires substantial amount of land which is a precious resource nowadays due to the rapid and unco

  8. Resonance of electromagnetic and mechanic coupling in hydro-generator

    Institute of Scientific and Technical Information of China (English)

    YAO Da-kun; ZOU Jing-xiang; QU Da-zhuang; ZHAO Shu-shan; YU Kai-ping

    2006-01-01

    Electromagnetic and mechanical forces are main reasons of oscillations in hydro-generators. The oscillation is fairly complicated as to the coupling of them. Using the method of multiple scales in nonlinear oscillations, instabilities of hydro-generator rotors caused by the unbalanced magnetic pull, which comes from the eccentricity of the rotor, are discussed. Considering nonlinear properties of the unbalanced magnetic pull, the super-harmonic resonance phenomena are observed as the critical rotating speed of rotors is close to twice of the operating speed. This is verified by a model experiment, and should be considered during the design of hydrogenerator rotors.

  9. Quantum Magneto-Optics in Graphene

    Directory of Open Access Journals (Sweden)

    Leonid Falkovsky

    2015-01-01

    Full Text Available The optical conductivity of graphene in quantizing magnetic fields is studied. Both dynamical conductivities, longitudinal and Hall’s, are analytically evaluated. The conductivity peaks are explained in terms of electron transitions. The optical transitions obey the selection rule with Δn = 1 for the Landau number n. The light transmission and Faraday rotation in the quantizing magnetic fields are calculated.

  10. Autoregressive bispectrum characteristics of magneto-rheometer

    Institute of Scientific and Technical Information of China (English)

    黄宜坚; 陈丙三; 蒋雨燕

    2008-01-01

    The operating principle of measuring rheological properties of magnetorheological(MR) fluid was expounded by means of a new rheometer with double driving discs rotating at the same speed in the opposite directions.The constitutive equation of MR fluid was established with theoretical analysis from experimental data.The conventional power spectrum approach was unable to detect the existence of quadratic phase coupling for dynamic rheological measurement.Bispectrum analysis is emerging as a new powerful technique in signal processing,which can describe nonlinear coupling,restrain Gaussian noise and reserve phase component.An autoregressive(AR) model of the third order cumulant,the bispectra and bispectral contours were utilized for analyzing the dynamic characteristics of the MR rheometer by merely using the sampled output torque signals when a zero mean non-Gaussian white noise interferes with the rotary disc system.The measurement and analysis process based on virtual instruments were automatically controlled by computer in this paper.The experimental and theoretical results show that rheological properties and dynamic characteristics of MR fluid can be measured with this double disc rheometer.

  11. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion

    DEFF Research Database (Denmark)

    Cukras, Janusz; Kauczor, Joanna; Norman, Patrick

    2016-01-01

    A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree–Fock and time-dependent density functional...... theory. Magneto-chiral dichroism and magneto-chiral birefringence spectra in the (resonant) frequency region below the first ionization threshold of R-methyloxirane and L-alanine are presented and compared with the corresponding results obtained for both the electronic circular dichroism and the magnetic...

  12. Large magneto-conductance and magneto-electroluminescence in exciplex-based organic light-emitting diodes at room temperature

    Science.gov (United States)

    Ling, Yongzhou; Lei, Yanlian; Zhang, Qiaoming; Chen, Lixiang; Song, Qunliang; Xiong, Zuhong

    2015-11-01

    In this work, we report on large magneto-conductance (MC) over 60% and magneto-electroluminescence (MEL) as high as 112% at room temperature in an exciplex-based organic light-emitting diode (OLED) with efficient reverse intersystem crossing (ISC). The large MC and MEL are individually confirmed by the current density-voltage characteristics and the electroluminescence spectra under various magnetic fields. We proposed that this type of magnetic field effect (MFE) is governed by the field-modulated reverse ISC between the singlet and triplet exciplex. The temperature-dependent MFEs reveal that the small activation energy of reverse ISC accounts for the large MFEs in the present exciplex-based OLEDs.

  13. Short range ferromagnetic, magneto-electric, and magneto-dielectric effect in ceramic Co3TeO6

    Science.gov (United States)

    Singh, Harishchandra; Ghosh, Haranath; Chandrasekhar Rao, T. V.; Sharma, G.; Saha, J.; Patnaik, S.

    2016-01-01

    We report observation of magneto-electric and magneto-dielectric couplings along with short range ferromagnetic order in ceramic Cobalt Tellurate (Co3TeO6, CTO) using magnetic, structural, dielectric, pyroelectric, and polarization studies. DC magnetization along with dielectric constant measurements indicate a coupling between magnetic order and electrical polarization. A strong anomaly in the dielectric constant at ˜17.4 K in zero magnetic field indicates spontaneous electric polarization, consistent with a recent neutron diffraction study. Observation of weak short range ferromagnetic order at lower temperatures is attributed to the Griffiths-like ferromagnetism. Furthermore, magnetic field dependence of the ferroelectric transition follows earlier theoretical predictions, applicable to single crystal CTO. Finally, combined dielectric, pyroelectric, and polarization measurements suggest that the ground state of CTO may possess spontaneous symmetry breaking in the absence of magnetic field.

  14. Mechatronics in compressor valves - experience with HydroCOM; Mechatronik in Kompressorventilen - Betriebserfahrungen mit HydroCOM

    Energy Technology Data Exchange (ETDEWEB)

    Rumpold, A. [Hoerbiger Ventilwerke GmbH, Wien (Austria)

    2000-03-01

    Optimisation of fluid flow rates is indispensable in piston compressor operation. Messrs. Hoerbiger are producers of continuous control elements which combine mechanical and electronic components. Applications and examples of the HydroCOM control system are presented. High availability permits servicing intervals around 160,000 hours of operation. The longer operating time will improve the competitive standing of piston compressors as compared to turbocompressors and screw compressors. [German] Fuer den Betrieb von Kolbenkompressoren ist eine optimale Liefermengenregelung unverzichtbarer Bestandteil. Im Gegensatz zu herkoemmlichen Verfahren hat Hoerbiger vor zwei Jahren durch die Kombination von Mechanik und Elektronik eine neue Generation von stufenlosen Mengenregelungen auf den Markt gebracht. Anwendungsbeispiele und Betriebserfahrungen mit der HydroCOM Regelung werden vorgestellt. Hohe Verfuegbarkeit erlaubt Wartungsintervalle fuer HydroCOM Aktuatoren von ca. 16000 Betriebsstunden. Und aufgrund der generell verbesserten Standzeiten von Packungen, Kolbenringen und Ventilen erzielt der so geregelte Kolbenkompressor hohe Attraktivitaet gegenueber Turbo- und Schraubenverdichtern. (orig./AKF)

  15. 80 FR 53510 - Owyhee Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

    Science.gov (United States)

    2015-09-04

    ...-000] Owyhee Hydro, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To Intervene, and Competing Applications On November 24, 2014, Owyhee Hydro, LLC (Owyhee..., 2015, Owyhee Hydro filed a revised application providing an additional alternative to the...

  16. 78 FR 7770 - Boyce Hydro Power, LLC; Notice of Application Accepted for Filing, Soliciting Motions To...

    Science.gov (United States)

    2013-02-04

    ... Energy Regulatory Commission Boyce Hydro Power, LLC; Notice of Application Accepted for Filing...: Amendment to License. b. Project No: 2785-081. c. Date Filed: September 11, 2012. d. Applicant: Boyce Hydro.... Applicant Contact: Lee W. Mueller, Boyce Hydro Power, LLC, 6000 S. M-30, Edenville, MI 48620, (989)...

  17. Magneto-Dielectric Wire Antennas Theory and Design

    Science.gov (United States)

    Sebastian, Tom

    There is a pervasive need in the defense industry for conformal, low-profile, efficient and broadband (HF-UHF) antennas. Broadband capabilities enable shared aperture multi-function radiators, while conformal antenna profiles minimize physical damage in army applications, reduce drag and weight penalties in airborne applications and reduce the visual and RF signatures of the communication node. This dissertation is concerned with a new class of antennas called Magneto-Dielectric wire antennas (MDWA) that provide an ideal solution to this ever-present and growing need. Magneto-dielectric structures (mur > 1; epsilon r > 1) can partially guide electromagnetic waves and radiate them by leaking off the structure or by scattering from any discontinuities, much like a metal antenna of the same shape. They are attractive alternatives to conventional whip and blade antennas because they can be placed conformal to a metallic ground plane without any performance penalty. A two pronged approach is taken to analyze MDWAs. In the first, antenna circuit models are derived for the prototypical dipole and loop elements that include the effects of realistic dispersive magneto-dielectric materials of construction. A material selection law results, showing that: (a) The maximum attainable efficiency is determined by a single magnetic material parameter that we term the hesitivity: Closely related to Snoek's product, it measures the maximum magnetic conductivity of the material. (b) The maximum bandwidth is obtained by placing the highest amount of mu" loss in the frequency range of operation. As a result, high radiation efficiency antennas can be obtained not only from the conventional low loss (low mu") materials but also with highly lossy materials (tan(deltam) >> 1). The second approach used to analyze MDWAs is through solving the Green function problem of the infinite magneto-dielectric cylinder fed by a current loop. This solution sheds light on the leaky and guided waves

  18. Magneto-hydrodynamics Simulation in Astrophysics

    Science.gov (United States)

    Pang, Bijia

    2011-08-01

    Magnetohydrodynamics (MHD) studies the dynamics of an electrically conducting fluid under the influence of a magnetic field. Many astrophysical phenomena are related to MHD, and computer simulations are used to model these dynamics. In this thesis, we conduct MHD simulations of non-radiative black hole accretion as well as fast magnetic reconnection. By performing large scale three dimensional parallel MHD simulations on supercomputers and using a deformed-mesh algorithm, we were able to conduct very high dynamical range simulations of black hole accretion of Sgr A* at the Galactic Center. We find a generic set of solutions, and make specific predictions for currently feasible observations of rotation measure (RM). The magnetized accretion flow is subsonic and lacks outward convection flux, making the accretion rate very small and having a density slope of around -1. There is no tendency for the flows to become rotationally supported, and the slow time variability of th! e RM is a key quantitative signature of this accretion flow. We also provide a constructive numerical example of fast magnetic reconnection in a three-dimensional periodic box. Reconnection is initiated by a strong, localized perturbation to the field lines and the solution is intrinsically three-dimensional. Approximately 30% of the magnetic energy is released in an event which lasts about one Alfvén time, but only after a delay during which the field lines evolve into a critical configuration. In the co-moving frame of the reconnection regions, reconnection occurs through an X-like point, analogous to the Petschek reconnection. The dynamics appear to be driven by global flows rather than local processes. In addition to issues pertaining to physics, we present results on the acceleration of MHD simulations using heterogeneous computing systems te{shan2006heterogeneous}. We have implemented the MHD code on a variety of heterogeneous and multi-core architectures (multi-core x86, Cell, Nvidia and

  19. Finite Difference Solution of Response Time Delay of Magneto-rhelological Damper

    Institute of Scientific and Technical Information of China (English)

    ZOU Mingsong; HOU Baolin

    2009-01-01

    Magneto-rhelological(MR) dampers are devices that employ rheological fluids to modify their mechanical properties. Their mechanical simplicity, high dynamic range, lower power requirements, large force capacity, robustness and safe manner of operation in cases of failure have made them attractive devices for semi-active real-time control in civil, aerospace and automotive applications. Time response characteristic is one of the most important technical performances of MR dampers, and response time directly affects the control frequency, application range and the actual effect of MR dampers. In this study, one kind of finite difference solution for predicting the response time of magneto-rheological dampers from "off-state" to "on-state" is put forward. A laminar flow model is used to describe the flow in the MR valve, and a bi-viscous fluid flow model is utilized to describe the relationship of shear stress and shear rate of MR fluid. An explicit difference format is used to discretize the Novior-Stoks equation, and stability condition of this algorithm is built by Von-Neumann stability criterion. The pressure gradient along the flow duct is solved by a dichotomy algorithm with iteration, and the changing curve of the damping force versus time of MR damper is obtained as well. According to the abovementioned numerical algorithm, the damping forces versus time curves from "off-state" to "on-state" of a cylindrical piston type MR damper are computed. Moreover, the MR damper is installed in a material test system(MTS), the magnetic field in the wire circles of the MR damper is "triggered" when the MR damper is imposed to do a constant speed motion, and the damping force curves are recorded. The comparison between numerical results and experimental results indicates that this finite difference algorithm can be used to estimate the response time delay of MR dampers.

  20. ENERGY EFFICIENT FLOW AND LEVEL CONTROL IN A HYDRO POWER PLANT USING FUZZY LOGIC

    Directory of Open Access Journals (Sweden)

    A. Selwin Mich Priyadharson

    2014-01-01

    Full Text Available The main objective and an innovative design of this work is to improve the energy efficiency by controlling the variables flow and level in a hydroelectric power plant using Programmable Logic Control (PLC-Human Machine Interface (HMI and fuzzy logic approach. This project will focus on design and development of flow and level controller for small scale hydro generating units by implementing gate control based on PLC-HMI and Fuzzy Logic Control (FLC. So far there is no other better performing control scheme, with uncomplicated approach, in order to match and satisfy the dynamic changes in load demand. In this project, FLC will be applied to flow and level control for small scale hydro generating units is proposed. A lab scale experimental setup is made-up as prototype model for flow and level control and simulation outputs were achieved, using PLC-HMI based fuzzy controller scheme. The hardware set up is designed with 5 stages in the tank 1 and 2 stages in the tank 2. Based on the outputs of the level sensors from tanks 1 and 2, the ladder logic will perform. B&R Industrial Automation PLC inbuilt with 24 digital inputs and provides 16 potential free outputs is used to perform control action. Finally, the performance of the proposed scheme is evaluated by simulation results by comparing with conventional controllers output using the data collected from the hydroelectric power plant. The merits of the proposed Fuzzy scheme over the conventional method are spotlighted.

  1. Hydro power plants on the Middle Sava River section

    Energy Technology Data Exchange (ETDEWEB)

    Kryzanowski, A; Horvat, A; Brilly, M [University of Ljubljana, Faculty of Civil and Geodetic Engineering, Chair of Hydrology and Hydraulic Engineering, Hajdrihova 28, Ljubljana (Slovenia)], E-mail: andrej.kryzanowski@geateh.si

    2008-11-01

    Construction of a chain of hydro power plants is planned on the Sava River from Medvode to the Slovenian-Croatian border which will, apart from the chain of HPPs on the Drava River, represent the linchpin of renewable energy production within the Slovenian power system. The mentioned chain of HPPs will also be one of the country's main renewable energy sources that can still be developed for power generation. Three hydro power plants, Moste, Mavccice and Medvode, are already operating on the Upper Sava River section. Construction of the chain is underway in the lower part of the stream where Vrhovo and Bosstanj HPPs are already in operation; HPP Blanca is under construction and the site planning procedures are taking place for Krsko, Brezice and Mokrice HPPs. The planned HPPs on the Middle Sava River section between Medvode and Zidani most will connect the HPPs on the Upper and Lower Sava River into a closed chain which will operate on the principle of run-of-river type power plants with daily storage. Completion of all stages will enable optimal development of available hydro potential. Apart from the energy effects, also other beneficial effects of hydro power plant construction in the region can be expected: flood protection; better water supply; waste water treatment; development of transport and energy networks as well as positive economic and social effects.

  2. Fuzzy interpolation of hydro power sales data in Simulink

    DEFF Research Database (Denmark)

    Jantzen, Jan; Eliasson, B.

    1994-01-01

    The problem in this case study can be described as a multi-dimensional surface fit to a given set of data. The data are sales figures in MWH/H for a hydro-thermal power generation system. The data are incomplete and not totally reliable. A model with ten fuzzy rules fits the data with a total error...

  3. Final Report - Wind and Hydro Energy Feasibility Study - June 2011

    Energy Technology Data Exchange (ETDEWEB)

    Jim Zoellick; Richard Engel; Rubin Garcia; Colin Sheppard

    2011-06-17

    This feasibility examined two of the Yurok Tribe's most promising renewable energy resources, wind and hydro, to provide the Tribe detailed, site specific information that will result in a comprehensive business plan sufficient to implement a favorable renewable energy project.

  4. The Selection of Cooling Systems of Giant Hydro-Generators

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The selection of cooling system for hydro-generator in Ertan Hydropower Station is reviewed in this paper. The new viewpoint on air-cooled system of hydraulic generator of recent years is analyzed and described. That is, "Full air-cooled system is always preferred to inner

  5. Virtues of simple hydro-economic optimization: Baja California, Mexico.

    Science.gov (United States)

    Medellín-Azuara, J; Mendoza-Espinosa, L G; Lund, J R; Harou, J J; Howitt, R E

    2009-08-01

    This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions.

  6. 75 FR 45607 - Application To Export Electric Energy; Manitoba Hydro

    Science.gov (United States)

    2010-08-03

    ... Application To Export Electric Energy; Manitoba Hydro AGENCY: Office of Electricity Delivery and Energy... authority to transmit electric energy from the United States to Canada pursuant to section 202(e) of the... Order No. EA-281, which authorized Manitoba to transmit electric energy from the United States to...

  7. Hydro-MRI for abdominal diagnostics in children; Hydro-MRT in der Darmdiagnostik bei Kindern

    Energy Technology Data Exchange (ETDEWEB)

    Kern, A.; Schunk, K.; Oberholzer, K.; Thelen, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Kessler, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Kinderchirurgie

    2001-11-01

    A clinical evaluation of hydro-MRI as an alternative method to barium studies in children with abdominal pain of unknown origin is presented. Patients and Methods: 20 children with abdominal pain of unknown origin aged from 9 - 16 years were examined after oral bowel opacification using 1000 ml of 2.5% mannitol solution with a 1.0T MRI system. The investigation was done in 2 planes (coronal and axial) under breath-hold conditions. Imaging procedures included various sequences (T2W HASTE + FS, contrast-enhanced T1W FLASH FS). Suspicious findings in bowel segments and extra-intestinal changes were assessed. Results: In 21/24 examinations the small bowel was completely visualized, in 15/24 cases colon segments were identified. An accurate assessment of the terminal ileum was not possible in 3/24 procedures. Breathing artefacts occurred in 3/24 examinations. Signs of Crohn's disease were found in 4 examinations, inflammatory changes of the ileum were detected in 3 cases. Inflammation of the colon was demonstrated in 2 children. Furthermore, pathological findings included constipation in one child and inflammation of the ileo-colic and mesenterial lymph nodes were found in another child. Extra-intestinal changes in 3 children were caused by ovarian cysts, and in one case by pleural effusion. In 4 examinations we detected ascites in the absence of other pathological findings. In 5 children there was no pathological correlation in the bowel or extra-intestinal region for the complaints. The children tolerated the hydro-MRI very well. There were no side effects using oral mannitol. (orig.) [German] Ziel: Klinische Evaluation der Hydro-MRT bei Kindern mit unklarer abdomineller Symptomatik als alternative Methode zur fraktionierten Magen-Darm-Passage. Patienten und Methoden: 20 Kinder und Jugendliche im Alter von 9 bis 16 Jahren mit unklaren abdominellen Beschwerden bzw. mit Verdacht auf eine chronisch entzuendliche Darmerkrankung wurden nach einer oralen

  8. A hydro-optical model for deriving water quality variables from satellite images (HydroSat): A case study of the Nile River demonstrating the future Sentinel-2 capabilities

    NARCIS (Netherlands)

    Salama, M.S.; Radwan, M.; van der Velde, R.

    2012-01-01

    This paper describes a hydro-optical model for deriving water quality variables from satellite images, hereafter HydroSat. HydroSat corrects images for atmospheric interferences and simultaneously retrieves water quality variables. An application of HydroSat to Landsat Enhanced Thematic Mapper (ETM)

  9. Energy supply technologies. Hydro, ocean, wave and tidal

    Energy Technology Data Exchange (ETDEWEB)

    Fenhann, J.; Larsen, Hans [Risoe National Lab. - DTU (Denmark)

    2007-11-15

    This chapter presents an overview of current hydro, ocean, wave and tidal initiatives. Large hydro remains one of the lowest-cost generating technologies, although environmental constraints, resettlement impacts and the limited availability of sites have restricted further growth in many countries. Large hydro supplied 16 % of global electricity in 2004, down from 19 % a decade ago. Large hydro capacity totalled about 720 GW worldwide in 2004 and has grown historically at slightly more than 2 % annually. China installed nearly 8 GW of large hydro in 2004, taking the country to number one in terms of installed capacity (74 GW). With the completion of the Three Gorges Dam, China will add some 18.2 GW of hydro capacity in 2009. The socio-economic benefits of hydro include improved flood control and water supply. The socio-economic benefits of hydro include improved flood control and water supply. The socio-economic cost of hydro includes displacements and submergence. Further hydro can improve peak-capacity management. Ocean currents, some of which runs close to European coasts, carry a lot of kinetic energy. Part of this energy can be captured by sub-marine windmills and converted into electricity. These are more compact than the wind turbines used on land, simply because water is much denser than air. The main European countries with useful current power potential are France and the UK. Ocean tides are driven by the gravitational pull of the moon. With one high tide every 12 hours, a tidal power plant can operate for only four or five hours per cycle, so power from a single plant is intermittent. A suitably-designed tidal plant can, however, operate as a pimped storage system, using electricity during periods of low demand to store energy that can be recovered later. The only large, modern example of a tidal power plant is the 240 MW La Rance plant, built in France in the 1960s, which represents 91 % of the world tidal power capacity. Wave energy can be seen as

  10. Sample-size resonance, ferromagnetic resonance and magneto-permittivity resonance in multiferroic nano-BiFeO3/paraffin composites at room temperature

    Science.gov (United States)

    Wang, Lei; Li, Zhenyu; Jiang, Jia; An, Taiyu; Qin, Hongwei; Hu, Jifan

    2017-01-01

    In the present work, we demonstrate that ferromagnetic resonance and magneto-permittivity resonance can be observed in appropriate microwave frequencies at room temperature for multiferroic nano-BiFeO3/paraffin composite sample with an appropriate sample-thickness (such as 2 mm). Ferromagnetic resonance originates from the room-temperature weak ferromagnetism of nano-BiFeO3. The observed magneto-permittivity resonance in multiferroic nano-BiFeO3 is connected with the dynamic magnetoelectric coupling through Dzyaloshinskii-Moriya (DM) magnetoelectric interaction or the combination of magnetostriction and piezoelectric effects. In addition, we experimentally observed the resonance of negative imaginary permeability for nano BiFeO3/paraffin toroidal samples with longer sample thicknesses D=3.7 and 4.9 mm. Such resonance of negative imaginary permeability belongs to sample-size resonance.

  11. SCATTERING OF ANTI-PLANE SHEAR WAVES BY A SINGLE CRACK IN AN UNBOUNDED TRANSVERSELY ISOTROPIC ELECTRO-MAGNETO-ELASTIC MEDIUM

    Institute of Scientific and Technical Information of China (English)

    杜建科; 沈亚鹏; 高波

    2004-01-01

    A theoretical treatment of the scattering of anti-plane shear (SH) waves is provided by a single crack in an unbounded transversely isotropic electro-magneto-elastic medium. Based on the differential equations of equilibrium, electric displacement and magnetic induction intensity differential equations, the governing equations for SH waves were obtained. By means of a linear transform, the governing equations were reduced to one Helmholtz and two Laplace equations. The Cauchy singular integral equations were gained by making use of Fourier transform and adopting electro-magneto impermeable boundary conditions. The closed form expression for the resulting stress intensity factor at the crack was achieved by solving the appropriate singular integral equations using Chebyshev polynomial. Typical examples are provided to show the loading frequency upon the local stress fields around the crack tips. The study reveals the importance of the electromagneto-mechanical coupling terms upon the resulting dynamic stress intensity factor.

  12. Nonlinear magneto-electric response of a giant magnetostrictive/piezoelectric composite cylinder

    Institute of Scientific and Technical Information of China (English)

    Yuan-Wen Gao; Juan-Juan Zhang

    2012-01-01

    In this study,we investigate the nonlinear coupling magneto-electric (ME) effect of a giant magnetostrictive/piezoelectric composite cylinder.The nonlinear constitutive relations of the ME material are taken into account,and the influences of the nonlinear material properties on the ME effect are investigated for the static and dynamic cases,respectively.The influences of different constraint conditions on the ME effect are discussed.In the dynamic case considering nonlinear material properties,the double frequency ME response (The response frequency is twice the applied magnetic frequency) is obtained and discussed,which can be used to explain the experiment phenomenon in which the input signal with frequency f is converted to the output signal with 2f in ME laminated structures.Some calculations on nonlinear ME effect are conducted.The obtained results indicate that the nonlinear material properties affect not only the magnitude of the ME effect in the static case but also the ME response frequency in the dynamic case.

  13. A magneto-rheological fluid mount featuring squeeze mode: analysis and testing

    Science.gov (United States)

    Chen, Peng; Bai, Xian-Xu; Qian, Li-Jun; Choi, Seung-Bok

    2016-05-01

    This paper presents a mathematical model for a new semi-active vehicle engine mount utilizing magneto-rheological (MR) fluids in squeeze mode (MR mount in short) and validates the model by comparing analysis results with experimental tests. The proposed MR mount is mainly comprised of a frame for installation, a main rubber, a squeeze plate and a bobbin for coil winding. When the magnetic fields on, MR effect occurs in the upper gap between the squeeze plate and the bobbin, and the dynamic stiffness can be controlled by tuning the applied currents. Employing Bingham model and flow properties between parallel plates of MR fluids, a mathematical model for the squeeze type of MR mount is formulated with consideration of the fluid inertia, MR effect and hysteresis property. The field-dependent dynamic stiffness of the MR mount is then analyzed using the established mathematical model. Subsequently, in order to validate the mathematical model, an appropriate size of MR mount is fabricated and tested. The field-dependent force and dynamic stiffness of the proposed MR mount are evaluated and compared between the model and experimental tests in both time and frequency domains to verify the model efficiency. In addition, it is shown that both the damping property and the stiffness property of the proposed MR mount can be simultaneously controlled.

  14. Spin dynamics in driven composite multiferroics

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zidong, E-mail: Zidong.Wang@auckland.ac.nz; Grimson, Malcolm J. [Department of Physics, The University of Auckland, Auckland 1010 (New Zealand)

    2015-09-28

    A spin dynamics approach has been used to study the behavior of the magnetic spins and the electric pseudo-spins in a 1-D composite multiferroic chain with a linear magneto-electric coupling at the interface. The response is investigated with either external magnetic or electric fields driving the system. The spin dynamics is based on the Landau-Lifshitz-Gilbert equation. A Gaussian white noise is later added into the dynamic process to include the thermal effects. The interface requires a closer inspection of the magneto-electric effects. Thus, we construct a 2-D ladder model to describe the behavior of the magnetic spins and the electric pseudo-spins with different magneto-electric couplings.

  15. Hydro power flexibility for power systems with variable renewable energy sources: an IEA Task 25 collaboration: Hydro power flexibility for power systems

    Energy Technology Data Exchange (ETDEWEB)

    Huertas-Hernando, Daniel [Department of Energy Systems, SINTEF, Trondheim Norway; Farahmand, Hossein [Department of Electric Power Engineering, Norwegian University of Science and Technology (NTNU), Trondheim Norway; Holttinen, Hannele [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Kiviluoma, Juha [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Rinne, Erkka [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Söder, Lennart [Department of Electrical Engineering, KTH University, Stockholm Sweden; Milligan, Michael [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Ibanez, Eduardo [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Martínez, Sergio Martín [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Gomez-Lazaro, Emilio [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Estanqueiro, Ana [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Rodrigues, Luis [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Carr, Luis [Research Association for Energy Economics (FfE GmbH), Munich Germany; van Roon, Serafin [Research Association for Energy Economics (FfE GmbH), Munich Germany; Orths, Antje Gesa [Energinet.dk, Fredericia Denmark; Eriksen, Peter Børre [Energinet.dk, Fredericia Denmark; Forcione, Alain [Hydro Quebec, Montréal Canada; Menemenlis, Nickie [Hydro Quebec, Montréal Canada

    2016-06-20

    Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.

  16. Alteration of Mesoscopic Properties and Mechanical Behavior of Sandstone Due to Hydro-Physical and Hydro-Chemical Effects

    Science.gov (United States)

    Qiao, Liping; Wang, Zhechao; Huang, Anda

    2017-02-01

    The hydro-physical and hydro-chemical interactions between groundwater and a rock mass can lead to changes in the mineral composition and structure of the rock (e.g., generation of voids and dissolution pores and an increase in the porosity), thereby altering the macroscopic mechanical characteristics of the rock mass. Sandstone specimens were saturated with distilled water and five aqueous solutions characterized by various ion concentrations and pH values for several months, and their porosity was measured in real time. Simultaneously, the concentration and pH of each aqueous solution were monitored every 30 days. The results indicate that after immersion in the aqueous solutions for 180 days, the porosity of the sandstone specimens and the ion concentrations and pH of the aqueous solutions tended to stabilize. Then, the immersed sandstone specimens were analyzed in thin section and subjected to computerized tomography scanning. It turns out that the mineral composition and structure of the specimens had all changed to various degrees. Finally, the uniaxial compression tests were conducted on the sandstone specimens to analyze the effects of the hydro-physical and hydro-chemical alteration on the macroscopic mechanical characteristics of the rock (e.g., the stress-strain relationship, elastic modulus, and peak strength). The results of this study can serve as a reference for investigations into theories and applications of water-rock interactions and for research in related fields.

  17. 77 FR 10740 - Lock+ Hydro Friends Fund XVIII, Upper Hydroelectric, LLC, FFP Project 95, LLC, Riverbank Hydro No...

    Science.gov (United States)

    2012-02-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Lock+ Hydro Friends Fund XVIII, Upper Hydroelectric, LLC, FFP Project 95... Friends Fund XVIII for Project No. 14261-000, Upper Hydroelectric, LLC for Project No. 14268-000,...

  18. 75 FR 75999 - Lock + Hydro Friends Fund XlVI; FFP Missouri 17, LLC; Solia 3 Hydroelectric, LLC; Three Rivers...

    Science.gov (United States)

    2010-12-07

    ... 3 Hydroelectric, LLC; Three Rivers Hydro, LLC; Hildebrand Hydro, LLC; Notice of Competing..., and Three Rivers Hydro LLC, and on May 19 Hildebrand Hydro, filed applications, pursuant to section 4... of Engineers (Corps) Hildebrand Lock & Dam located on the Monongahela River in Monongahela...

  19. Magneto switch microcircuit and wind speed measurement’s sensor on its base

    Directory of Open Access Journals (Sweden)

    Kasimov F. D.

    2009-04-01

    Full Text Available The magneto switch microcircuit on the base of Hall-effect is developed. The electric scheme of the magneto sensitive IC was designed and its basic technical characteristics are described. The gauge of wind speed on its base is fabricated.

  20. Nonlinear magneto-optical effects in cold atoms of 87Rb

    Institute of Scientific and Technical Information of China (English)

    He Ling-Xiang; Wang Yu-Zhu

    2004-01-01

    With laser-cooled cold 87Rb atoms as a magneto-optical medium, a weak right circularly polarized probe field and frequency modulation technique are used to detect the magnetic distribution of the quadrupole field. A two-peak dispersion-like signal other than that of the usual nonlinear magneto-optical effect mentioned in other papers is obtained.

  1. Developing of operational hydro-meteorological simulating and displaying system

    Science.gov (United States)

    Wang, Y.; Shih, D.; Chen, C.

    2010-12-01

    Hydrological hazards, which often occur in conjunction with extreme precipitation events, are the most frequent type of natural disaster in Taiwan. Hence, the researchers at the Taiwan Typhoon and Flood Research Institute (TTFRI) are devoted to analyzing and gaining a better understanding of the causes and effects of natural disasters, and in particular, typhoons and floods. The long-term goal of the TTFRI is to develop a unified weather-hydrological-oceanic model suitable for simulations with local parameterizations in Taiwan. The development of a fully coupled weather-hydrology interaction model is not yet completed but some operational hydro-meteorological simulations are presented as a step in the direction of completing a full model. The predicted rainfall data from Weather Research Forecasting (WRF) are used as our meteorological forcing on watershed modeling. The hydrology and hydraulic modeling are conducted by WASH123D numerical model. And the WRF/WASH123D coupled system is applied to simulate floods during the typhoon landfall periods. The daily operational runs start at 04UTC, 10UTC, 16UTC and 22UTC, about 4 hours after data downloaded from NCEP GFS. This system will execute 72-hr weather forecasts. The simulation of WASH123D will sequentially trigger after receiving WRF rainfall data. This study presents the preliminary framework of establishing this system, and our goal is to build this earlier warning system to alert the public form dangerous. The simulation results are further display by a 3D GIS web service system. This system is established following the Open Geospatial Consortium (OGC) standardization process for GIS web service, such as Web Map Service (WMS) and Web Feature Service (WFS). The traditional 2D GIS data, such as high resolution aerial photomaps and satellite images are integrated into 3D landscape model. The simulated flooding and inundation area can be dynamically mapped on Wed 3D world. The final goal of this system is to real

  2. Experimental and numerical investigation of hydro power generator ventilation

    Science.gov (United States)

    Jamshidi, H.; Nilsson, H.; Chernoray, V.

    2014-03-01

    Improvements in ventilation and cooling offer means to run hydro power generators at higher power output and at varying operating conditions. The electromagnetic, frictional and windage losses generate heat. The heat is removed by an air flow that is driven by fans and/or the rotor itself. The air flow goes through ventilation channels in the stator, to limit the electrical insulation temperatures. The temperature should be kept limited and uniform in both time and space, avoiding thermal stresses and hot-spots. For that purpose it is important that the flow of cooling air is distributed uniformly, and that flow separation and recirculation are minimized. Improvements of the air flow properties also lead to an improvement of the overall efficiency of the machine. A significant part of the windage losses occurs at the entrance of the stator ventilation channels, where the air flow turns abruptly from tangential to radial. The present work focuses exclusively on the air flow inside a generator model, and in particular on the flow inside the stator channels. The generator model design of the present work is based on a real generator that was previously studied. The model is manufactured taking into consideration the needs of both the experimental and numerical methodologies. Computational Fluid Dynamics (CFD) results have been used in the process of designing the experimental setup. The rotor and stator are manufactured using rapid-prototyping and plexi-glass, yielding a high geometrical accuracy, and optical experimental access. A special inlet section is designed for accurate air flow rate and inlet velocity profile measurements. The experimental measurements include Particle Image Velocimetry (PIV) and total pressure measurements inside the generator. The CFD simulations are performed based on the OpenFOAM CFD toolbox, and the steady-state frozen rotor approach. Specific studies are performed, on the effect of adding "pick-up" to spacers, and the effects of the

  3. Experimental study of the anisotropic magneto-Seebeck effect in (Ga,Mn)As thin films

    Energy Technology Data Exchange (ETDEWEB)

    Althammer, Matthias; Krupp, Alexander T.; Brenninger, Thomas; Venkateshvaran, Deepak; Opel, Matthias; Gross, Rudolf; Goennenwein, Sebastian T.B. [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Dreher, Lukas [Walter Schottky Institut, Technische Universitaet Muenchen, Garching (Germany); Schoch, Wladimir; Limmer, Wolfgang [Abteilung Halbleiterphysik, Universitaet Ulm, Ulm (Germany)

    2011-07-01

    In analogy to anisotropic magnetoresistance (AMR), the thermopower of ferromagnetic materials also characteristically depends on the orientation of the magnetization vector. This anisotropic magneto-thermopower - or anisotropic magneto-Seebeck effect (AMS) - has only scarcely been studied to date. Taking the ferromagnetic semiconductor (Ga,Mn)As with its large magneto-resistive effects as a prototype example, we have measured the evolution of both the AMR and the AMS effects at liquid He temperatures as a function of the orientation of a magnetic field applied in the (Ga,Mn)As film plane, for different, fixed magnetic field magnitudes. Our data show that the AMS effect can be adequately modeled only if the symmetry of the (Ga,Mn)As crystal is explicitly taken into account. We quantitatively compare our AMR and AMS measurements with corresponding model calculations, and address the validity of the Mott relations linking the magneto-resistance and the magneto-Seebeck coefficients.

  4. Thickness dependent enhancement of the polar magneto-optic Kerr effect in Co magnetoplasmonic nanostructures

    CERN Document Server

    Melander, Emil; Caballero, Blanca; García-Martín, Antonio; Hjörvarsson, Björgvin; Kapaklis, Vassilios; Papaioannou, Evangelos Th

    2016-01-01

    We reveal the influence of the thickness of the ferromagnetic layer on the surface plasmon polariton assisted enhancement of the polar magneto-optic Kerr effect. The optical and magneto-optical response is strongly altered by the thickness of the magnetic layer as shown in specular reflectivity and polar magneto-optical Kerr effect measurements. That the main spectral feature of the magneto-optical enhancement does not only depend on the in-plane structuring of the sample but also on the out-of-plane geometrical parameters, such as the thickness. For the specific thickness of 100 nm for the Co layer an sixfold enhancement of the polar magneto-optical effect is observed, as compared to a continuous Co film of the same thickness.

  5. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion.

    Science.gov (United States)

    Cukras, Janusz; Kauczor, Joanna; Norman, Patrick; Rizzo, Antonio; Rikken, Geert L J A; Coriani, Sonia

    2016-05-21

    A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree-Fock and time-dependent density functional theory. Magneto-chiral dichroism and magneto-chiral birefringence spectra in the (resonant) frequency region below the first ionization threshold of R-methyloxirane and l-alanine are presented and compared with the corresponding results obtained for both the electronic circular dichroism and the magnetic circular dichroism. The additional information content yielded by the magneto-chiral phenomena, as well as their potential experimental detectability for the selected species, is discussed.

  6. From first-order magneto-elastic to magneto-structural transition in (Mn,Fe)1.95P0.50Si0.50 compounds

    NARCIS (Netherlands)

    Dung, N. H.; Zhang, L.; Ou, Z. Q.; Brück, E.

    2011-01-01

    We report on structural, magnetic, and magnetocaloric properties of MnxFe1.95−xP0.50Si0.50 (x ≥ 1.10) compounds. With increasing the Mn:Fe ratio, a first-order magneto-elastic transition gradually changes into a first-order magneto-structural transition via a second-order magnetic transition. The st

  7. Generalized magneto-optical ellipsometry in ferromagnetic metals

    Energy Technology Data Exchange (ETDEWEB)

    Neuber, G.; Rauer, R.; Kunze, J.; Backstrom, J.; Ruebhausen, M

    2004-05-01

    We present spectral generalized magneto-optical ellipsometry as an optical tool to investigate magnetic and electronic properties of ferromagnetic materials. The advantage of the simultaneous observation of the dielectric and the magnetic responses within one measurement procedure is crucial for materials with coupled degrees of freedom near a phase transition or during annealing procedures to improve the film quality by removing grain boundaries. Moreover, we show the implementation of this technique within an UHV-cryostat for a temperature range between 4.2 and 800 K and fields up to 40 mT. Examplary measurements on iron and Permalloy demonstrate the comfortable application of this technique.

  8. Cold Atom Source Containing Multiple Magneto-Optical Traps

    Science.gov (United States)

    Ramirez-Serrano, Jaime; Kohel, James; Kellogg, James; Lim, Lawrence; Yu, Nan; Maleki, Lute

    2007-01-01

    An apparatus that serves as a source of a cold beam of atoms contains multiple two-dimensional (2D) magneto-optical traps (MOTs). (Cold beams of atoms are used in atomic clocks and in diverse scientific experiments and applications.) The multiple-2D-MOT design of this cold atom source stands in contrast to single-2D-MOT designs of prior cold atom sources of the same type. The advantages afforded by the present design are that this apparatus is smaller than prior designs.

  9. Magneto-optical color imaging of magnetic field distribution

    Directory of Open Access Journals (Sweden)

    Yosuke Nagakubo

    2017-05-01

    Full Text Available The magneto-optical (MO imaging technique allows magnetic field distributions to be observed in real-time. In this paper, we demonstrate a MO color imaging technique that allows quantitative values of magnetic fields to be determined by the naked eye. MO color imaging is realized using a MO imaging plate, which contains a bismuth-substituted iron garnet film. The imaging plate was prepared by the metal organic decomposition method, and a light source consisting of green and yellow light-emitting diodes or a white light-emitting diode. MO color imaging of the magnetic field distribution of a commercial ferrite magnet is demonstrated.

  10. Integrated magneto-optical traps on a chip

    CERN Document Server

    Pollock, S; Laliotis, A; Hinds, E A

    2009-01-01

    We have integrated magneto-optical traps (MOTs) into an atom chip by etching pyramids into a silicon wafer. These have been used to trap atoms on the chip, directly from a room temperature vapor of rubidium. This new atom trapping method provides a simple way to integrate several atom sources on the same chip. It represents a substantial advance in atom chip technology and offers new possibilities for atom chip applications such as integrated single atom or photon sources and molecules on a chip.

  11. A Magneto-Optical Trap for Polar Molecules

    CERN Document Server

    Stuhl, Benjamin K; Wang, Dajun; Ye, Jun

    2008-01-01

    We propose a method for laser cooling and trapping a substantial class of polar molecules, and in particular titanium (II) oxide (TiO). This method uses pulsed electric fields to nonadiabatically remix the ground-state magnetic sublevels of the molecule, allowing us to build a magneto-optical trap (MOT) based on a quasi-cycling $J'=J"-1$ transition. Monte-Carlo simulations of this electrostatically remixed MOT (ER-MOT) demonstrate the feasibility of cooling TiO to a temperature of 10 $\\mathrm{\\mu}K$ and trapping it with a radiation-pumping-limited lifetime on the order of 80 ms.

  12. Fabrication of magneto-optical microstructure by femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    Yudong Li; Xiangyang Gao; Meiling Jiang; Qian Sun; Jianguo Tian

    2012-01-01

    We investigate femtosecond laser direct writing (FLDW) in the fabrication of magneto-optical (MO) microstructures.The experimental results show that FDLW can introduce positive refractive index change in the MO materials.With the increase of the writing intensity of femtosecond laser pulses,refractive index change increases,whereas Verdet constant of the damaged area decreases nonlinearly.With suitable writing intensity,we obtain a single-mode waveguide in which Verdet constant is 80% of the bulkMO glass.

  13. Multiple Isotope Magneto Optical Trap from a single diode laser

    CERN Document Server

    Valenzuela, V M; Gutierrez, M; Gomez, E; 10.1364/JOSAB.30.001205

    2013-01-01

    We present a Dual Isotope Magneto Optical Trap produced using a single diode laser. We generate all the optical frequencies needed for trapping both species using a fiber intensity modulator. All the optical frequencies are amplified simultaneously using a tapered amplifier. The independent control of each frequency is on the RF side rather than on the optical side. This introduces an enormous simplification for laser cooling applications that often require an acousto-optic modulator for each laser beam. Frequency changing capabilities are limited by the modulator bandwidth (10 GHz). Traps for more isotopes can be simply added by including additional RF frequencies to the modulator.

  14. Magneto-resistive and spin valve heads fundamentals and applications

    CERN Document Server

    Mallinson, John C

    2002-01-01

    This book is aims to be a comprehensive source on the physics and engineering of magneto-resistive heads. Most of the material is presented in a nonmathematical manner to make it more digestible for researchers, students, developers, and engineers.In addition to revising and updating material available in the first edition, Mallinson has added nine new chapters dealing with various aspects concerning spin valves, the electron spin tunneling effect, the electrostatic discharge effects, read amplifiers, and signal-to-noise ratios, making this a completely up-to-date reference.Th

  15. Wave propagation in reconfigurable magneto-elastic kagome lattice structures

    Science.gov (United States)

    Schaeffer, Marshall; Ruzzene, Massimo

    2015-05-01

    The paper discusses the wave propagation characteristics of two-dimensional magneto-elastic kagome lattices. Mechanical instabilities caused by magnetic interactions are exploited in combination with particle contact to bring about changes in the topology and stiffness of the lattices. The analysis uses a lumped mass system of particles, which interact through axial and torsional elastic forces as well as magnetic forces. The propagation of in-plane waves is predicted by applying Bloch theorem to lattice unit cells with linearized interactions. Elastic wave dispersion in these lattices before and after topological changes is compared, and large differences are highlighted.

  16. Theoretical and Experimental Studies of Magneto-Rayleigh-Taylor Instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Yue Ying [University of Michigan, Ann Arbor, MI (United States); Gilgenbach, Ronald [University of Michigan, Ann Arbor, MI (United States)

    2013-07-07

    Magneto-Rayleigh-Taylor instability (MRT) is important to magnetized target fusion, wire-array z-pinches, and equation-of-state studies using flyer plates or isentropic compression. It is also important to the study of the crab nebula. The investigators performed MRT experiments on thin foils, driven by the mega-ampere linear transformer driver (LTD) facility completed in their laboratory. This is the first 1-MA LTD in the USA. Initial experiments on the seeding of MRT were performed. Also completed was an analytic study of MRT for a finite plasma slab with arbitrary magnetic fields tangential to the interfaces. The effects of magnetic shear and feedthrough were analyzed.

  17. Relativistic Cherenkov radiation in a magneto-dielectric media

    Directory of Open Access Journals (Sweden)

    2016-09-01

    Full Text Available In this paper, relativistic Cherenkov radiation was studied in a 3-D magneto-dielectric medium. Electric permittivity and magnetic permeability of the medium as functions of frequency, are assumed to satisfy Kramers- Kronig equations. A new interaction Hamiltonian, which is different from Hamiltonian term in non-relativistic state, was introduced by the quantized vector potential field and particle field operator obtained from the second quantization method. The rate of electron energy dissipation was calculated using Fermi’s golden rule.

  18. Magneto-chiral dichroism of CsCuCl3

    Science.gov (United States)

    Nakagawa, N.; Abe, N.; Toyoda, S.; Kimura, S.; Zaccaro, J.; Gautier-Luneau, I.; Luneau, D.; Kousaka, Y.; Sera, A.; Sera, M.; Inoue, K.; Akimitsu, J.; Tokunaga, Y.; Arima, T.

    2017-09-01

    In this Rapid Communication, we investigate the magneto-chiral dichroism (MChD) of right- and left-handed CsCuCl3 crystals in a strong magnetic field up to 14.5 T. We perform near-infrared optical measurements, and the results show a change in the absorption coefficient of an intra-atomic d -d transition in a Cu2 + ion at approximately 1.5 eV. The magnitude of MChD was found to be proportional to the magnetization, which depends on the magnetic field and temperature. We verify this relation by developing a simple CuCl6 cluster model.

  19. Forbidden transitions in a magneto-optical trap.

    Science.gov (United States)

    Bhattacharya, M; Haimberger, C; Bigelow, N P

    2003-11-21

    We report the first observation of a nondipole transition in an ultracold atomic vapor. We excite the 3P-4P electric quadrupole (E2) transition in 23Na confined in a magneto-optical trap, and we demonstrate its application to high-resolution spectroscopy by making the first measurement of the hyperfine structure of the 4P(1/2) level and extracting the magnetic dipole constant A=30.6+/-0.1 MHz. We use cw optical-optical double resonance accompanied by photoionization to probe the transition.

  20. Understanding Astrophysical Noise from Stellar Surface Magneto-Convection

    CERN Document Server

    Cegla, H M; Shelyag, S; Mathioudakis, M

    2014-01-01

    To obtain cm/s precision, stellar surface magneto-convection must be disentangled from observed radial velocities (RVs). In order to understand and remove the convective signature, we create Sun-as-a-star model observations based on a 3D magnetohydrodynamic solar simulation. From these Sun-as-a-star model observations, we find several line characteristics are correlated with the induced RV shifts. The aim of this campaign is to feed directly into future high precision RV studies, such as the search for habitable, rocky worlds, with forthcoming spectrographs such as ESPRESSO.

  1. The relativistic electro-vortical field—revisiting magneto-genesis and allied problems

    Science.gov (United States)

    Mahajan, Swadesh M.

    2016-11-01

    Following the idea of MagnetoFluid unification [S. M. Mahajan, Phys. Rev. Lett. 90, 035001 (2003)], a very general Electro-Vortical (EV) field is constructed to describe the dynamics of a perfect relativistic fluid. Structurally similar to the electromagnetic field Fμν , the Electro-Vortical field Mνμ unifies the macroscopic forces into a single grand force that is the weighted sum of the electromagnetic and the inertial/thermal forces. The new effective force may be viewed either as a vortico-thermal generalization of the electromagnetic force or as the electromagnetic generalization of the vortico-thermal forces that a fluid element experiences in course of its evolution. Two fundamental consequences follow from this grand unification: (1) emergences of a new helicity that is conserved for arbitrary thermodynamics and (2) the entire dynamics is formally expressible as an MHD (magnetohydrodynamics) like ideal Ohm's law in which the "electric" and "magnetic" components of the EV field replace the standard electric and magnetic fields. In the light of these more and more encompassing conserved helicities, the "scope and significance" of the classical problem of magneto-genesis (need for a seed field to get a dynamo started) is reexamined. It is shown that in models more advanced than MHD, looking for exotic seed-generation mechanisms (like the baroclinic thermodynamics) should not constitute a fundamental pursuit; the totally ideal dynamics is perfectly capable of generating and sustaining magnetic fields entirely within its own devices. For a specified thermodynamics, a variety of exact and semi exact self-consistent analytical solutions for equilibrium magnetic and flow fields are derived for a single species charged fluid. The scale lengths of the fields are determined by two natural scale lengths: the skin depth and the gradient length of the thermodynamic quantities. Generally, the skin depth, being the shorter (even much shorter) than the gradient length

  2. An effective stress approach for hydro-mechanical coupling of unsaturated soils

    Directory of Open Access Journals (Sweden)

    Arroyo Hiram

    2016-01-01

    Full Text Available The simulation of the mechanical and hydraulic behaviour of soils is one of the most important tasks in soil mechanics. It is inaccurate to consider that the behaviour of saturated and unsaturated soils as if their governing laws were utterly different, this last condition is not sufficient to do so. However, unlike the laws governing the behaviour of saturated soils, those used to describe the behaviour of unsaturated soils lack the simplicity and predictability associated to the complexity of the phenomena that occur within these porous media. This is why it is important to establish a unified soil mechanics theory to reconcile saturated and unsaturated soil mechanics. In the present work, we describe a simple analytical equation to obtain effective stresses for any type of soil. The equation is coupled to an elastoplastic constitutive model which is capable to reproduce the stress-strain relationship of soil taking into account the hydro-dynamic coupling.

  3. Hydro-physical processes and soil properties correlated with origin of soil hydrophobicity

    Directory of Open Access Journals (Sweden)

    Eduardo Saldanha Vogelmann

    2013-09-01

    Full Text Available Hydrophobicity is the phenomenon where the soil has reduced wettability, usually associated with coating of soil particles by hydrophobic organic substances. This study aimed to provide a description of the hydrophobicity occurrence, highlight recent discoveries about the origin of phenomenon and discuss the main hydro-physical properties and chemical processes linked to the development of hydrophobic behavior in soils. Hydrophobicity is associated with other factors such as soil moisture, presence of some fungi species, particle size, soil pH and occurrence of burnings. The causative substances may be provided by local vegetation, through deposition or decomposition. The dependence and combination of different factors that influence hydrophobicity in soils lead to a spatial and temporal variability of the phenomenon, with negative consequences in the processes of infiltration and water percolation, affecting the three-dimensional distribution and dynamics of soil moisture. Thus, the occurrence of a hydrophobic character requires special attention, especially regarding soil use and management.

  4. A new PID controller design for automatic generation control of hydro power systems

    Energy Technology Data Exchange (ETDEWEB)

    Khodabakhshian, A.; Hooshmand, R. [Electrical Engineering Department, University of Isfahan (Iran)

    2010-06-15

    This paper presents a new robust PID controller for automatic generation control (AGC) of hydro turbine power systems. The method is mainly based on a maximum peak resonance specification that is graphically supported by the Nichols chart. The open-loop frequency response curve is tangent to a specified ellipse and this makes the method to be efficient for controlling the overshoot, the stability and the dynamics of the system. Comparative results of this new load frequency controller with a conventional PI one and also with another PID controller design tested on a multimachine power system show the improvement in system damping remarkably. The region of acceptable performance of the new PID controller covers a wide range of operating and system conditions. (author)

  5. Rejecting hydro-biogeochemical model structures by multi-criteria evaluation

    Science.gov (United States)

    Houska, Tobias; Kraft, Philipp; Liebermann, Ralf; Klatt, Steffen; Kraus, David; Haas, Edwin; Santabarbara, Ignacio; Kiese, Ralf; Butterbach-Bahl, Klaus; Müller, Christoph; Breuer, Lutz

    2017-04-01

    This work presents a novel way for assessing and comparing different hydro-biogeochemical model structures and their performances. We used the LandscapeDNDC modelling framework to set up four models of different complexity, considering two soil-biogeochemical and two hydrological modules. The performance of each model combination was assessed using long-term (8 years) data and applying different thresholds, considering multiple criteria and objective functions. Our results show that each model combination had its strength for particular criteria. However, only 0.01% of all model runs passed the complete rejectionist framework. In contrast, our comparatively applied assessments of single thresholds, as frequently used in other studies, lead to a much higher acceptance rate of 40 to 70%. Therefore, our study indicates that models can be right for the wrong reasons, i.e., matching GHG emissions while at the same time failing to simulate other criteria such as soil moisture or plant biomass dynamics.

  6. M9 Tohoku Earthquake Hydro- and Seismic Response in the Caucasus and North Turkey

    Science.gov (United States)

    Chelidze, Tamaz L.; Shengelia, Ia; Zhukova, Natalya; Matcharashvili, Teimuraz; Melikadze, George; Kobzev, Genady

    2016-06-01

    Presently, there are a lot of observations on the significant impact of strong remote earthquakes on underground water and local seismicity. Teleseismic wave trains of strong earthquakes give rise to several hydraulic effects in boreholes, namely permanent water level changes and water level oscillations, which closely mimic the seismograms (hydro-seismograms). Clear identical anomalies in the deep borehole water levels have been observed on a large part of the territory of Georgia during passing of the S and Love-Rayleigh teleseismic waves (including also multiple surface Rayleigh waves) of the 2011 Tohoku M9 earthquake. The analysis carried out in order to find dynamically triggered events (non-volcanic tremors) of the Tohoku earthquake by the accepted methodology has not revealed a clear tremor signature in the test area: the Caucasus and North Turkey. The possible mechanisms of some seismic signals of unknown origin observed during passage of teleseismic waves of Tohoku earthquake are discussed.

  7. Modelling and simulation of the fuel cell energy source for the Hydro-Gen vehicle; Modelisation et simulation de la source d'energie a pile a combustible du vehicule Hydro-Gen

    Energy Technology Data Exchange (ETDEWEB)

    Schott, P.; Baurens, P. [CEA Grenoble, Dept. d' Etudes des Materiaux, DEM, 38 (France); Poirot, J.Ph. [PSA/DRIA/SEE, 78 - Velizy Villacoublay (France)

    2000-07-01

    A fuel cell generating set is a complex system in which the interactions between the different elements are chemical, hydraulic, thermal, mechanical and electric. The implementation and the optimization of such a system cannot be limited to the study of each element; the system analysis and then the modelling and the dynamical simulation are necessarily required. The bond-graphs theory is particularly well adapted to the multiplicity of the involved phenomena. In this article is presented the modelling used for the generating set of the Hydro-Gen plan. Some representative examples are given as well as the first qualitative results of the simulations. (O.M.)

  8. Bifurcations and chaos of a vibration isolation system with magneto-rheological damper

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2016-03-01

    Full Text Available Magneto-rheological (MR damper possesses inherent hysteretic characteristics. We investigate the resulting nonlinear behaviors of a two degree-of-freedom (2-DoF MR vibration isolation system under harmonic external excitation. A MR damper is identified by employing the modified Bouc-wen hysteresis model. By numerical simulation, we characterize the nonlinear dynamic evolution of period-doubling, saddle node bifurcating and inverse period-doubling using bifurcation diagrams of variations in frequency with a fixed amplitude of the harmonic excitation. The strength of chaos is determined by the Lyapunov exponent (LE spectrum. Semi-physical experiment on the 2-DoF MR vibration isolation system is proposed. We trace the time history and phase trajectory under certain values of frequency of the harmonic excitation to verify the nonlinear dynamical evolution of period-doubling bifurcations to chaos. The largest LEs computed with the experimental data are also presented, confirming the chaotic motion in the experiment. We validate the chaotic motion caused by the hysteresis of the MR damper, and show the transitions between distinct regimes of stable motion and chaotic motion of the 2-DoF MR vibration isolation system for variations in frequency of external excitation.

  9. Bifurcations and chaos of a vibration isolation system with magneto-rheological damper

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hailong [Magneto-electronics Lab, School of Physics and Technology, Nanjing Normal University, Nanjing 210046 (China); Vibration Control Lab, School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing 210042 (China); Zhang, Ning [Magneto-electronics Lab, School of Physics and Technology, Nanjing Normal University, Nanjing 210046 (China); Min, Fuhong; Yan, Wei; Wang, Enrong, E-mail: erwang@njnu.edu.cn [Vibration Control Lab, School of Electrical and Automation Engineering, Nanjing Normal University, Nanjing 210042 (China)

    2016-03-15

    Magneto-rheological (MR) damper possesses inherent hysteretic characteristics. We investigate the resulting nonlinear behaviors of a two degree-of-freedom (2-DoF) MR vibration isolation system under harmonic external excitation. A MR damper is identified by employing the modified Bouc-wen hysteresis model. By numerical simulation, we characterize the nonlinear dynamic evolution of period-doubling, saddle node bifurcating and inverse period-doubling using bifurcation diagrams of variations in frequency with a fixed amplitude of the harmonic excitation. The strength of chaos is determined by the Lyapunov exponent (LE) spectrum. Semi-physical experiment on the 2-DoF MR vibration isolation system is proposed. We trace the time history and phase trajectory under certain values of frequency of the harmonic excitation to verify the nonlinear dynamical evolution of period-doubling bifurcations to chaos. The largest LEs computed with the experimental data are also presented, confirming the chaotic motion in the experiment. We validate the chaotic motion caused by the hysteresis of the MR damper, and show the transitions between distinct regimes of stable motion and chaotic motion of the 2-DoF MR vibration isolation system for variations in frequency of external excitation.

  10. Coherent magneto-elastic oscillations in superfluid magnetars

    Science.gov (United States)

    Gabler, Michael; Cerdá-Durán, Pablo; Stergioulas, Nikolaos; Font, José A.; Müller, Ewald

    2016-08-01

    We study the effect of superfluidity on torsional oscillations of highly magnetised neutron stars (magnetars) with a microphysical equation of state by means of two-dimensional, magneto-hydrodynamical-elastic simulations. The superfluid properties of the neutrons in the neutron star core are treated in a parametric way in which we effectively decouple part of the core matter from the oscillations. Our simulations confirm the existence of two groups of oscillations, namely continuum oscillations that are confined to the neutron star core and are of Alfvénic character, and global oscillations with constant phase and that are of mixed magneto-elastic type. The latter might explain the quasi-periodic oscillations observed in magnetar giant flares, since they do not suffer from the additional damping mechanism due to phase mixing, contrary to what happens for continuum oscillations. However, we cannot prove rigorously that the coherent oscillations with constant phase are normal modes. Moreover, we find no crustal shear modes for the magnetic field strengths typical for magnetars. We provide fits to our numerical simulations that give the oscillation frequencies as functions of magnetic field strength and proton fraction in the core.

  11. Magneto-Photoinduced Absorption in Organic Polymer Films

    Science.gov (United States)

    Gautam, Bhoj; Nguyen, Tho; Ehrenfreund, Eitan; Vardeny, Z. Valy

    2012-02-01

    In order to elucidate the underlying mechanism of magneto-conductivity (MC) in OLEDs we studied magneto-photoinduced absorption (MPA) response in polymer films. The films were based on the MEH-PPV polymer in three different forms, namely: pristine film; film exposed to prolonged UV illumination; and MEH-PPV/PCBM blend having weight ratio 1:1. In pristine film we show that the MPA at low excitation intensity is due to sublevel spin mixing of triplet excitons; whereas at high excitation intensity the MPA is dominated by the triplet-triplet annihilation process. In UV illuminated MEH-PPV films that support photogenerated polarons we show that the MPA is due to sublevel spin-mixing of polaron-pairs via the hyperfine interaction with the closest hydrogen atoms to the chain. This mechanism also explains the MC response of OLED based on MEH-PPV, since its response is similar to that of MPA. Finally we found that the MPA in MEH-PPV/PCBM blend films is dominated by spin mixing of polaron-pair on the polymer and fullerene molecules, via the δg mechanism. Supported by the NSF DMR-1104495, the NSF MRSEC at the UoU, and the BSF program.

  12. Management of dam safety at BC Hydro: the database tool

    Energy Technology Data Exchange (ETDEWEB)

    Oswell, Terry [BC Hydrom Burnaby, (Canada)

    2010-07-01

    BC Hydro has a wide range of dams, which raises a wide range of issues at many unique sites. A dam safety database was developed in 2000 to deal with the complexity and volume of information provided by deficiency investigations and surveillances. The database contains all documented deficiencies and non-conformances identified in the past 10 years. It records the risk ratings assigned to each issue. This paper described the implementation of the database tool, from the characterization of a dam safety issue to the use of the database itself. The dam safety database is now a key tool in managing the dam safety program at BC Hydro and has been useful for the last 10 years or so in prioritizing the program of deficiency investigations and capital projects. The development of a process to rate non-conformances is currently under study and will be implemented soon to aid in more efficient prioritization of maintenance activities.

  13. Digital Manufacture Techniques for Large Hydro Turbine's Blades

    Institute of Scientific and Technical Information of China (English)

    LAI Xide; ZHANG Qinghua; ZHOU Yunfei; YAN Sijie

    2006-01-01

    Blades are one of the vital components and most difficulty in manufacturing of large hydro turbines. In order to cost-effectively and productively manufacture these kinds of blades, a series of digital techniques in manufacturing have been developed, which includes digital design of hydro turbine blades based on manufacture' requirements, Computer-aided location and the machined error evaluation by using 3-dimensional digitized measuring, tool path generation strategy to meet requirements of enhancing machining efficiency and controlling deviation in NC machining, tool path generation and NC machining simulation by establishing a virtual NC machining environment for blades, and reasonable and feasible strategy and the systematic scheme for manufacturing of large blades by using 5-axis simultaneous CNC machining. The developed digital manufacture techniques have been successfully applied in manufacturing of both the large Kaplan and Francis hydraulic turbine blades; it shows that higher efficiency and the better surfaces finish accuracy can be achieved.

  14. Optimal design of axial hydro turbine for micro hydropower plants

    Science.gov (United States)

    Derakhshan, S.; Kasaeian, N.

    2012-11-01

    In our country we have enormous low head potation flows in agricultures and aquacultures with almost fix flow rates that can be used as micro hydro power plants for producing energy. But the main problem is the high capital price per kW. Therefore there is needed to design a simple machine with a good runner for covering the various potential flows. In this paper an axial hydro turbine has designed for some low heads micro potential flow with flow rates ranged from 50 lit/sec to 150 lit/sec and heads ranged from 1 m to 5 m. The initial runner designed using classical methods and then the runner geometry has been optimized by evolutionary optimization algorithms. The final design has been simulated by a commercial flow solver in a various blade positions. The results showed a wide range characteristic curve with a wide range high efficiency.

  15. Design of damping valve for vehicle hydro pneumatic suspension

    Institute of Scientific and Technical Information of China (English)

    Mingming DONG; Hua HUANG; Lian GU

    2008-01-01

    According to the design features of a hydro pneumatic spring, the necessity of a separate damping valve is proposed. Based on a 1/4 vehicle linear suspension model, the optimum damping coefficient is worked out and the parameters of the damping valve are determined with the equivalent linearization method. A practical structure of the damping valve is proposed having a small size, high flowrate when the valve opens, and the ability of enduring high back pressure. Based on bench tests, the damping valve has been found to properly work and be suitable. The design method and damping valve structure are useful guides for hydro pneumatic suspension, especially for the design of heavy-duty vehicles.

  16. Valley-spin polarization in the magneto-optical response of silicene and other similar 2D crystals.

    Science.gov (United States)

    Tabert, C J; Nicol, E J

    2013-05-10

    We calculate the magneto-optical conductivity and electronic density of states for silicene, the silicon equivalent of graphene, and similar crystals such as germanene. In the presence of a perpendicular magnetic field and electric field gating, we note that four spin- and valley-polarized levels can be seen in the density of states, and transitions between these levels lead to similarly polarized absorption lines in the longitudinal, transverse Hall, and circularly polarized dynamic conductivity. While previous spin and valley polarization predicted for the conductivity is only present in the response to circularly polarized light, we show that distinct spin and valley polarization can also be seen in the longitudinal magneto-optical conductivity at experimentally attainable energies. The frequency of the absorption lines may be tuned by the electric and magnetic field to onset in a range varying from THz to the infrared. This potential to isolate charge carriers of definite spin and valley label may make silicene a promising candidate for spin- and valleytronic devices.

  17. A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping.

    Science.gov (United States)

    Tripathi, Dharmendra; Bég, O Anwar

    2012-08-01

    Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations.

  18. NH4-smectite: Characterization, hydration properties and hydro mechanical behaviour

    OpenAIRE

    2010-01-01

    International audience; Leachates in waste landfills are characterized by the presence of ammonium ions in large excess. These ammonium ions can be exchanged with the interlayer cations in clay and modify the physical and chemical properties of clay geochemical barriers in waste landfills and drive to environmental problems. The purpose of this study was to understand the hydro-physical changes of a smectite in the presence of ammonium ions. An ammonium smectite was prepared by cation exchang...

  19. Fracture and springback on Double Bulge Tube Hydro-Forming

    OpenAIRE

    F. Djavanroodi; M. Gheisary

    2008-01-01

    This research aims to establish a basic understanding of Double Bulge Tube Hydro-Form processing of stainless steel deep drawn cups. The method is briefly reviewed by carrying out experimental tests and Finite element analysis. By measuring bulge height in both formed curves by Coordinate measuring machine (CMM) and thickness variation specimen by Ulterasonic thickness measurment device (UTM), it has been shown that maximum thinness occured where the bending is maximized. A finite element mod...

  20. Pico hydro power for rural electrification in developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Maher, P.; Smith, N.P.A. [Nottingham Trent Univ., Dept. of Electrical Engineering, Nottingham (United Kingdom); Williams, A.A. [Nottingham Trent Univ., Dept. of Mechanical and Manufacturing Engineering, Nottingham (United Kingdom)

    1998-07-01

    Pico hydro power is a renewable energy system which has the potential to provide millions of rural people world-wide with a cheap, sustainable source of electricity. The development of new, cost-reducing approaches, including local manufacture and implementation in developing countries, has increased the accessibility of this technology to large numbers of people. The new approaches are investigated and some of the present constraints to wider adoption of this technology are analysed. (Author)

  1. Simulation aided testing of hydro-mechanical processes on clay

    OpenAIRE

    Vaunat J.; Romero E.; Merchán V.

    2010-01-01

    This paper presents a study focused on the hydro-mechanical behaviour of a plastic clay under partially saturated conditions. Clay remoulded samples were dried using vapour transfer under one-dimensional conditions. Samples underwent an important vertical shrinkage on drying, which progressed along more than one week. To study the time evolution of this phenomenon, simulation aided techniques were used to analyse the progression of suction at local scale and to determine the time requir...

  2. Coupled hydro-mechanical model for expansive clays

    Science.gov (United States)

    Koudelka, Tomáš; Krejčí, Tomáš; Kruis, Jaroslav

    2017-07-01

    The paper deals with the hydro-mechanical model for expansive clayey soils. The complex model is based on the hypoplasticity, which parameters are influenced by suction, and additionally on Schrefler's model for saturated-unsaturated water flow in deforming porous medium. The model has been implemented into the open source software SIFEL and selected results of a simple numerical example are presented in the last section of the paper.

  3. Fracture and springback on Double Bulge Tube Hydro-Forming

    Directory of Open Access Journals (Sweden)

    F. Djavanroodi

    2008-01-01

    Full Text Available This research aims to establish a basic understanding of Double Bulge Tube Hydro-Form processing of stainless steel deep drawn cups. The method is briefly reviewed by carrying out experimental tests and Finite element analysis. By measuring bulge height in both formed curves by Coordinate measuring machine (CMM and thickness variation specimen by Ulterasonic thickness measurment device (UTM, it has been shown that maximum thinness occured where the bending is maximized. A finite element model is constructed to simulate the Double Bulge Tube Hydro Forming process and asses the influence of friction cofficient, tube Material properties and springback. It has been shown that material hardening coefficient had the most significant influence on formability characteristics during double bulge tube hydroforming. Also it is shown that springback has significant effect on tolerances of formed tube. Finally fracture strain was estimated by analytical method and compared with simulation results, also fracture location was predicted on Double Bulge Tube Hydro-Forming (DBTHF by simulating the process.

  4. Source reliability in a combined wind-solar-hydro system

    Science.gov (United States)

    Traca de Almeida, A.; Martins, A.; Jesus, H.; Climaco, J.

    1983-06-01

    The results of an examination of the feasibility of using coupled wind-solar-hydro power generation systems to provide all of Portugal's electricity by the year 2000 are reported. Portugal used 15.6 TWh of electricity in 1981, of which hydro supplied 10 TWh. Demand is expected to reach 34 TWh in 2000 AD. The full development of hydropower resource would furnish 18 TWh and a storage capacity of 4.5 TWh. The installed hydro system could meet the peak demand of 6 GW, while solar cells and wind turbines must produce 16 TWh annually plus a reserve. The Growian wind turbine, 100 m tall, is considered for its 2.2 MW output. A coastal strip of wind turbines 150 x 20 km, with 1 km spacing between the machines, would be needed to produce 5.4 GW of power. Partially tracking solar cell arrays generating 9.4 GW of electricity would require an area of 100 sq km. Computer simulations of the annual rainfall, combined with projections of the variations in wind-solar output, demonstrates that a reserve margin of 1.20 will be necessary. The costs of installation of the renewable energy converters are estimated at about three times that currently necessary for obtaining the same capacity from fission power plants, although the situation may change due to import and technical considerations.

  5. Study of hydro-saline characteristics of soils a palm grove in basin of Ouargla (Northern Algerian Sahara)

    Science.gov (United States)

    Rezagui, D.; Bouhoun, M. Daddi; Boutoutaou, D.; Djaghoubi, A.

    2016-07-01

    Saharan soils are often faced with several problems of development, taking account the hydro-edaphic constraints, mainly of hydric types by water table, mechanical by gypso-calcareous crusts and saline by irrigation waters and upwelling of water table. Our work consists in doing a soil characterization of a palm grove in Ouargla in order to study the constraints hydro-halomorphes. The results show that irrigation water by two plies of Senonian and Mioplcène had a high salinity with a value of 2.83 and 5.10 dS.m-1 respectively. The conduct of irrigation is traditional random of submersion type. The palm grove has a poor drainage with a level of water table 156.67±15.71 cm and salinity of 31.37±34.04 dS.m-1. The drains are open type and their maintenance is not regular. This situation of management of irrigation-drainage promotes the upwelling of water table and the waterlogging in soils. The study of soil profiles shows the existence of mechanical obstruction of gypso-calcareous crusts which limit the entrenchment of the date palms and the leaching of salts. Soil salinity is excessive in profiles with a range of 8.98 ± 4.58 dS.m-1. This accumulation of salts is due to the dynamic ascending and descending of salts respectively under the effect of upwelling of water table and leaching by irrigation. The salinization, the upwelling of water table and the presence of gypso-calcareous crusts recorded in Ouargla testify to a degradation hydro-halomorphe and mechanic of soil which constitute the major constraints in the management of system irrigation-drainage and sustainable agricultural development of the palm groves of the basin of Ouargla. Some hydro-agricultural planning are necessary to apply in the oasis to improve the hydro-mechanical properties of soils in order to reduce their degradation.

  6. Thermo-hydro-mechanical behaviour of Boom clay; Comportement thermo-hydro-mecanique de l'argile de Boom

    Energy Technology Data Exchange (ETDEWEB)

    Le, T.T

    2008-01-15

    This thesis studied the thermo-hydro-mechanical properties of Boom clay, which was chosen to be the host material for the radioactive waste disposal in Mol, Belgium. Firstly, the research was concentrated on the soil water retention properties and the hydro-mechanical coupling by carrying out axial compression tests with suction monitoring. The results obtained permitted elaborating a rational experimental procedure for triaxial tests. Secondly, the systems for high pressure triaxial test at controlled temperature were developed to carry out compression, heating, and shearing tests at different temperatures. The obtained results showed clear visco-elasto-plastic behaviour of the soil. This behaviour was modelled by extending the thermo-elasto-plastic model of Cui et al. (2000) to creep effect. (author)

  7. Community micro-hydro in LDCs: adoption, management and poverty impact

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-09-15

    This project has developed methodologies and action plans through consultation, by which community-based micro-hydro can be implemented in target African countries. This was achieved through the study of the successful adoption of micro-hydro in Nepal and Sri Lanka. The study showed that the success of micro-hydro in Nepal and Sri Lanka depended on using the technology for applications for which people had a strong interest. In Nepal, the demand for mechanical power for food processing led to rapid growth of the micro-hydro industry, while electricity generation proved more attractive in Sri Lanka. Similar factors to those in Nepal are allowing the Ethiopian micro-hydro programme to develop, and this project has enabled key Ethiopian stakeholders to learn from the Nepal experience. There appears to be potential demand for micro-hydro in Uganda, but further investigation is required to find suitable sites and applications for the technology. (author)

  8. Fluid dynamics transactions

    CERN Document Server

    Fiszdon, W

    1965-01-01

    Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co

  9. Therapeutic efficacy of hydro-kinesiotherapy Programs in lumbar spondylosis

    Directory of Open Access Journals (Sweden)

    Ana-Maria BOTEZAN

    2015-12-01

    Full Text Available Lumbar spondylarthrosis is a degenerative disease that affects the joint structures of the lumbar spine. In the course of time, numerous studies on the role of hydro-kinesiotherapy in the treatment of lumbar spondylosis have been conducted. The aim of this research is motivated by the significantly high number of patients with chronic pain in the lumbar spine due to lumbar spondylosis, as well as by the negative impact on their quality of life through the impairment of the activities of daily living. The prospective longitudinal study was carried out at the Clinical Rehabilitation Hospital Cluj-Napoca. The study included 35 patients with chronic low back pain and mobility limitation in the lumbar spine. The patients were assigned to two groups: the study group formed by 20 patients and the control group consisting of 15 patients aged between 40-70 years. The treatment of the patients included in the study was performed over a two week period and consisted of a hydro-kinesiotherapy program, for the patients of the study group, the duration of a treatment session being 40 minutes. Both the subjects of the study group and of the control group also benefited from sedative massage of the lumbosacral spine, kinesiotherapy, laser therapy of the lumbar spine. The patients were evaluated using Schober’s test, the Visual Analogue Scale, the Oswestry index. These evaluation methods were applied to the patients of both groups at the beginning of the rehabilitation programs and after two weeks. The results of the study demonstrated the therapeutic efficacy of the medical rehabilitation programs that included hydro-kinesiotherapy programs. The patients of both groups had improvements through a decrease of lumbar pain, an increase in lumbar spine mobility, as well as in the patients’ ability to organize themselves in the activities of daily living. However, the patients of the study group, with a hydro-kinesiotherapy program performed for two weeks, had

  10. Magneto-optical Effect and Its Applications%磁光效应及其应用

    Institute of Scientific and Technical Information of China (English)

    缪秀平

    2011-01-01

    本文简介了磁光效应(包括法拉第效应、克尔效应、塞曼效应和磁线振双折射效应等)的基本理论以及各种磁光器件的特性及原理。%We introduced the basic theories of magneto-optical effects(including Faraday effect,Kerr effect,Zeeman effect and magnetic linear birefringence effect) and the progress in research of various magneto-optical materials and magneto-optical devices are briefly introduced.

  11. Hexapole-compensated magneto-optical trap on a mesoscopic atom chip

    DEFF Research Database (Denmark)

    Jöllenbeck, S.; Mahnke, J.; Randoll, R.

    2011-01-01

    Magneto-optical traps on atom chips are usually restricted to small atomic samples due to a limited capture volume caused primarily by distorted field configurations. Here we present a magneto-optical trap based on a millimeter-sized wire structure which generates a magnetic field with minimized...... distortions. Together with the loading from a high-flux two-dimensional magneto-optical trap, we achieve a loading rate of 8.4×1010 atoms/s and maximum number of 8.7×109 captured atoms. The wire structure is placed outside of the vacuum to enable a further adaptation to new scientific objectives. Since all...

  12. Hydro-mechanical mechanism and thresholds of rainfall-induced unsaturated landslides

    Science.gov (United States)

    Yang, Zongji; Lei, Xiaoqin; Huang, Dong; Qiao, Jianping

    2017-04-01

    The devastating Ms 8 Wenchuan earthquake in 2008 created the greatest number of co-seismic mountain hazards ever recorded in China. However, the dynamics of rainfall induced mass remobilization and transport deposits after giant earthquake are not fully understood. Moreover, rainfall intensity and duration (I-D) methods are the predominant early warning indicators of rainfall-induced landslides in post-earthquake region, which are a convenient and straight-forward way to predict the hazards. However, the rainfall-based criteria and thresholds are generally empirical and based on statistical analysis,consequently, they ignore the failure mechanisms of the landslides. This study examines the mechanism and hydro-mechanical behavior and thresholds of these unsaturated deposits under the influence of rainfall. To accomplish this, in situ experiments were performed in an instrumented landslide deposit, The field experimental tests were conducted on a natural co-seismic fractured slope to 1) simulate rainfall-induced shallow failures in the depression channels of a debris flow catchment in an earthquake-affected region, 2)explore the mechanisms and transient processes associated with hydro-mechanical parameter variations in response to the infiltration of rainfall, and 3) identify the hydrologic parameter thresholds and critical criteria of gravitational erosion in areas prone to mass remobilization as a source of debris flows. These experiments provided instrumental evidence and directly proved that post-earthquake rainfall-induced mass remobilization occurred under unsaturated conditions in response to transient rainfall infiltration, and revealed the presence of transient processes and the dominance of preferential flow paths during rainfall infiltration. A hydro-mechanical method was adopted for the transient hydrologic process modelling and unsaturated slope stability analysis. and the slope failures during the experimental test were reproduced by the model

  13. Role of Pumped Storage Hydro Resources in Electricity Markets and System Operation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ela, E.; Kirby, B.; Botterud, A.; Milostan, C.; Krad, I.; Koritarov, V.

    2013-05-01

    The most common form of utility- sized energy storage system is the pumped storage hydro system. Originally, these types of storage systems were economically viable simply because they displace more expensive generating units. However, over time, as those expensive units became more efficient and costs declined, pumped hydro storage units no longer have the operational edge. As a result, in the current electricity market environment, pumped storage hydro plants are struggling. To offset this phenomenon, certain market modifications should be addressed. This paper will introduce some of the challenges faced by pumped storage hydro plants in today's markets and purpose some solutions to those problems.

  14. A magneto-sensitive skin for robots in space

    Science.gov (United States)

    Chauhan, D. S.; Dehoff, P. H.

    1991-01-01

    The development of a robot arm proximity sensing skin that can sense intruding objects is described. The purpose of the sensor would be to prevent the robot from colliding with objects in space including human beings. Eventually a tri-mode system in envisioned including proximity, tactile, and thermal. To date the primary emphasis was on the proximity sensor which evolved from one based on magneto-inductive principles to the current design which is based on a capacitive-reflector system. The capacitive sensing element, backed by a reflector driven at the same voltage and in phase with the sensor, is used to reflect field lines away from the grounded robot toward the intruding object. This results in an increased sensing range of up to 12 in. with the reflector on compared with only 1 in. with it off. It is believed that this design advances the state-of-the-art in capacitive sensor performance.

  15. Active control of magneto-hydrodynamic instabilities in hot plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Igochine, Valentin (ed.) [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    2015-04-01

    Written and edited by leading plasma physics researchers. Provides a toolkit for scientists and engineers aiming to optimize plasma performance. Comprehensive treatment of different plasma instabilities. During the past century, world-wide energy consumption has risen dramatically, which leads to a quest for new energy sources. Fusion of hydrogen atoms in hot plasmas is an attractive approach to solve the energy problem, with abundant fuel, inherent safety and no long-lived radioactivity. However, one of the limits on plasma performance is due to the various classes of magneto-hydrodynamic instabilities that may occur. The physics and control of these instabilities in modern magnetic confinement fusion devices is the subject of this book. Written by foremost experts, the contributions will provide valuable reference and up-to-date research reviews for ''old hands'' and newcomers alike.

  16. Magneto-Vortex Dynamo Model in Solar convection zone

    CERN Document Server

    Ershkov, Sergey V

    2011-01-01

    Here is presented a new magneto-vortex dynamo model for modeling & predicting of a processes in Solar plasma convection zone. Solar convection zone is located above the level r > 0,6-0,7 R, where R is a Solar radius. A key feature of such a model is that equation of Solar plasma motion as well as equation of magnetic fields evolution - are reduced to Helmholtz's vortex equation, which is up-graded in according with alpha-effect (Coriolis force forms an additional vorticity field or magnetic field due to Sun's differential rotation). Such an additional vorticity or magnetic field are proved to be concentrated at the proper belt in Solar convection zone under the influence of Coriolis force (at the middle latitudes of the Sun in respect to equator). Besides, such an an additional vorticity & magnetic fields are to be the basic sources of well-known phenomena "Maunder's butterfly" diagram.

  17. Magneto-thermoelectric effects in NiFe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Maximilian

    2015-11-01

    In this thesis magneto-thermoelectric effects are investigated in a systematic way to separate the transverse spin Seebeck effect from other parasitic effects like the anomalous Nernst effect. In contrast to the first studies found in the literature, in NiFe thin films a contribution of the transverse spin Seebeck effect can be excluded. This surprising outcome was crosschecked in a variety of different sample layouts and collaborations with other universities to ensure the validity of these results. In general, this thesis solves a long time discussion about the existence of the transverse spin Seebeck effect in NiFe films and supports the importance of control measurements for the scientific community. Even if such ''negative'' results may not be the award winning ones, new discoveries should be treated with constructive criticism and be checked carefully by the scientific community.

  18. The Magneto-Rotational Decay Instability in Keplerian Disks

    CERN Document Server

    Shtemler, Yuri; Mond, Michael

    2013-01-01

    The saturation of the magnetorotational (MRI) instability in thin Keplerian disks through three wave resonant interactions is introduced and discussed. That mechanism is a natural generalization of the fundamental decay instability discovered five decades ago for infinite, homogeneous and immovable plasmas. The decay instability relies on the energy transfer from the MRI to stable slow Alfv'en-Coriolis (AC) as well as magnetosonic (MS) waves. A second order forced Duffing amplitude equation for the initially unstable MRI as well as two first order equations for the other two waves are derived. The solutions of those equations exhibit bounded bursty nonlinear oscillations for the MRI as well as unbounded growth for the linearly stable slow AC and MS perturbations, thus giving rise to the magneto-rotational decay instability (MRDI).

  19. A Magneto-Optical Trap for Diatomic Molecules

    Science.gov (United States)

    Yeo, Mark; Hummon, Matthew; Collopy, Alejandra; Stuhl, Benjamin; Hemmerling, Boerge; Chae, Eunmi; Drayna, Garrett; Ravi, Aakash; Kuhnert, Maximilian; Petzold, Maurice; Doyle, John; Ye, Jun

    2014-05-01

    The magneto-optical trap (MOT) has long been the workhorse for atomic physics and is a powerful technique to rapidly produce ultracold, dense samples of atoms. Extending this technique to produce cold, dense samples of a diverse set of molecules will revolutionize the study of strongly interacting quantum systems, precision measurement and physical chemistry. In this work, we will report on progress towards the realization of a 3 dimensional MOT for the polar molecule YO. We are implementing a chirped frequency laser slowing scheme, where the buffer gas cooled molecules are slowed to a trappable velocity of 10 m/s. The 3D trapping is generated with a quasi-cycling transition and an oscillating quadrupole magnetic field. Current affiliation: Joint Quantum Institute, NIST and University of Maryland.

  20. Effects of High Magneto-Gravitational Environment on Silkworm Embryogenesis

    Science.gov (United States)

    Tian, Zongcheng; Li, Muwang; Qian, Airong; Xu, Huiyun; Wang, Zhe; Di, Shengmeng; Yang, Pengfei; Hu, Lifang; Ding, Chong; Zhang, Wei; Luo, Mingzhi; Han, Jing; Gao, Xiang; Huang, Yongping; Shang, Peng

    2010-04-01

    The objective of this research was to observe whether silkworm embryos can survive in a high magneto-gravitational environment (HMGE) and what significant phenotype changes can be produced. The hatching rate, hatching time, life span, growth velocity and cocoon weight of silkworm were measured after silkworm embryos were exposed to HMGE (0 g, 12 T; 1 g, 16 T; and 2 g, 12 T) for a period of time. Compared with the control group, 0 g exposure resulted in a lower hatching rate and a shorter life span. Statistically insignificant morphological changes had been observed for larvae growth velocity, incidence of abnormal markings and weight of cocoons. These results suggest that the effect of HMGE on silkworm embryogenesis is not lethal. Bio-effects of silkworm embryogenesis at 0 g in a HMGE were similar with those of space flight. The hatching time, life span and hatching rates of silkworm may be potential phenotype markers related to exposure in a weightless environment.

  1. Integrated Magneto-Electrochemical Sensor for Exosome Analysis.

    Science.gov (United States)

    Jeong, Sangmoo; Park, Jongmin; Pathania, Divya; Castro, Cesar M; Weissleder, Ralph; Lee, Hakho

    2016-02-23

    Extracellular vesicles, including exosomes, are nanoscale membrane particles that carry molecular information on parental cells. They are being pursued as biomarkers of cancers that are difficult to detect or serially follow. Here we present a compact sensor technology for rapid, on-site exosome screening. The sensor is based on an integrated magneto-electrochemical assay: exosomes are immunomagnetically captured from patient samples and profiled through electrochemical reaction. By combining magnetic enrichment and enzymatic amplification, the approach enables (i) highly sensitive, cell-specific exosome detection and (ii) sensor miniaturization and scale-up for high-throughput measurements. As a proof-of-concept, we implemented a portable, eight-channel device and applied it to screen extracellular vesicles in plasma samples from ovarian cancer patients. The sensor allowed for the simultaneous profiling of multiple protein markers within an hour, outperforming conventional methods in assay sensitivity and speed.

  2. Oxidation processes in magneto-optic and related materials

    Science.gov (United States)

    Lee, Paul A.; Armstrong, Neal R.; Danzinger, James L.; England, Craig D.

    1992-01-01

    The surface oxidation processes of thin films of magneto-optic materials, such as the rare-earth transition metal alloys have been studied, starting in ultrahigh vacuum environments, using surface analysis techniques, as a way of modeling the oxidation processes which occur at the base of a defect in an overcoated material, at the instant of exposure to ambient environments. Materials examined have included FeTbCo alloys, as well as those same materials with low percentages of added elements, such a Ta, and their reactivities to both O2 and H2O compared with materials such as thin Fe films coated with ultrathin adlayers of Ti. The surface oxidation pathways for these materials is reviewed, and XPS data presented which indicates the type of oxides formed, and a critical region of Ta concentration which provides optimum protection.

  3. Saturation of Photoassociation in Cs Magneto-optical Trap

    Institute of Scientific and Technical Information of China (English)

    MA Jie; WANG Li-Rong; JI Wei-Bang; XIAO Lian-Tuan; JIA Suo-Tang

    2007-01-01

    An ultrahigh resolution photoassociation spectrum of caesium atoms in a magneto-optical trap is presented. Hyperfine structure of the excited state molecule is obtained by using the lock-in method based on modulated cold atoms in this spectrum. Amplitude of resonant lines related to the rotational levels increases with photoassociation laser intensity, and saturation effect of photoassociation of cold atoms is observed in our experiment. The saturation intensity of photoassociation is deduced by fitting the experimental data to a saturation model based on scattering theory. Differences among saturation intensities of different rotational progressions in the v = 55vibrational state of the caesium molecular long-range O-g state have been found.

  4. Magneto-volume effects in Fe-Cu solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, P. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)]. E-mail: pgorria@uniovi.es; Martinez-Blanco, D. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Iglesias, R. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Palacios, S.L. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Perez, M.J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Fernandez Barquin, L. [Departamento CITIMAC, F. Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Hernando, A. [Instituto de Magnetismo Aplicado, UCM-RENFE, 28230 Las Rozas, Madrid (Spain); Gonzalez, M.A. [Instituto de Ciencia de Materiales de Aragon, CSIC, 50009 Zaragoza (Spain); Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

    2006-05-15

    The magnetic properties of Fe-Cu metastable solid solutions have been investigated by means of neutron diffraction and magnetisation measurements. These compounds exhibit ferromagnetic order with Curie temperatures above room temperature for concentrations beyond 40 at% in Fe. The magnetic moment at 5 K can reach values over 2 {mu} {sub B}, while the high field susceptibility is similar to that found in FCC-FeNi Invar alloys. These features together with the low values for the linear coefficient for thermal expansion in the ferromagnetic region suggest that magneto-volume anomalies, including Invar behaviour, play a major role in the magnetic properties of this system when the crystal structure is face centred cubic. Such behaviour could be explained using theoretical total-band energy calculations.

  5. Single-laser, one beam, tetrahedral magneto-optical trap.

    Science.gov (United States)

    Vangeleyn, Matthieu; Griffin, Paul F; Riis, Erling; Arnold, Aidan S

    2009-08-03

    We have realized a 4-beam pyramidal magneto-optical trap ideally suited for future microfabrication. Three mirrors split and steer a single incoming beam into a tripod of reflected beams, allowing trapping in the four-beam overlap volume. We discuss the influence of mirror angle on cooling and trapping, finding optimum efficiency in a tetrahedral configuration. We demonstrate the technique using an ex-vacuo mirror system to illustrate the previously inaccessible supra-plane pyramid MOT configuration. Unlike standard pyramidal MOTs both the pyramid apex and its mirror angle are non-critical and our MOT offers improved molasses free from atomic shadows in the laser beams. The MOT scheme naturally extends to a 2-beam refractive version with high optical access. For quantum gas experiments, the mirror system could also be used for a stable 3D tetrahedral optical lattice.

  6. Coherent magneto-elastic oscillations in superfluid magnetars

    CERN Document Server

    Gabler, Michael; Stergioulas, Nikolaos; Font, José A; Müller, Ewald

    2016-01-01

    We study the effect of superfluidity on torsional oscillations of highly magnetised neutron stars (magnetars) with a microphysical equation of state by means of two-dimensional, magnetohydrodynamical- elastic simulations. The superfluid properties of the neutrons in the neutron star core are treated in a parametric way in which we effectively decouple part of the core matter from the oscillations. Our simulations confirm the existence of two groups of oscillations, namely continuum oscillations that are confined to the neutron star core and are of Alfv\\'enic character, and global oscillations with constant phase and that are of mixed magneto-elastic type. The latter might explain the quasi-periodic oscillations observed in magnetar giant flares, since they do not suffer from the additional damping mechanism due to phase mixing, contrary to what happens for continuum oscillations. However, we cannot prove rigorously that the coherent oscillations with constant phase are normal modes. Moreover, we find no crust...

  7. Magneto-inductive Sensors for Metallic Ropes in Lift Application

    Directory of Open Access Journals (Sweden)

    Aldo CANOVA

    2010-12-01

    Full Text Available In this paper an innovative system for the contemporary, selective and reliable control of integrity of multiple rope plants is presented. The system is based on magneto-inductive technology and is composed by a magnetic detector connected to an acquisition system. The core of the detector is constituted by an array of Hall sensors properly placed inside the instrument. After a brief introduction to the Non Destructive Techniques applied to the control of metallic ropes, the first part paper deals with the design and behavior of the detector and the acquisition system. In the second part of the paper a performance analysis for different rope size and experimental results on an elevator plants is presented and discussed.

  8. Magneto-optical trap for neutral mercury atoms

    Institute of Scientific and Technical Information of China (English)

    Liu Hong-Li; Yin Shi-Qi; Liu Kang-Kang; Qian Jun; Xu Zhen; Hong Tao; Wang Yu-Zhu

    2013-01-01

    Due to its low sensitivity to blackbody radiation,neutral mercury is a good candidate for the most accurate optical lattice clock.Here we report the observation of cold mercury atoms in a magneto-optical trap (MOT).Because of the high vapor pressure at room temperature,the mercury source and the cold pump were cooled down to-40 ℃ and-70 ℃,respectively,to keep the science chamber in an ultra-high vacuum of 6× 10-9 Pa.Limited by the power of the UV cooling laser,the one beam folded MOT configuration was adopted,and 1.5× 105 Hg-202 atoms were observed by fluorescence detection.

  9. Magneto-Rayleigh-Taylor growth and feedthrough in cylindrical liners

    Science.gov (United States)

    Weis, Matthew; Lau, Y. Y.; Gilgenbach, Ronald; Peterson, Kyle; Hess, Mark

    2013-10-01

    Cylindrical liner implosions in the MagLIF concept are susceptible to the magneto-Rayleigh-Taylor instability (MRT). The linearized ideal MHD equations are solved, including the presence of an axial magnetic field and the effects of sausage and kink modes. The eigenmode solution, using appropriate equilibrium profiles, allows an assessment of the local MRT growth rate and of the instantaneous feedthrough factor during the entire implosion process. Of particular interest will be the high convergence/stagnation phase, which is difficult to image experimentally. Strong axial magnetic fields can mitigate feedthrough and MRT growth, which may be useful at the fuel/liner interface during this phase of the MagLIF implosion. For the MRT growth rate and feedthrough factors, the LLNL code, HYDRA, is used to benchmark with the analytic theory, and with experiments on the Z-machine. This work was supported by DoE and NSF.

  10. The role of boundaries in the MagnetoRotational Instability

    CERN Document Server

    Gissinger, Christophe; Ji, Hantao

    2012-01-01

    In this paper, we investigate numerically the flow of an electrically conducting fluid in a cylindrical Taylor-Couette flow when an axial magnetic field is applied. To minimize Ekman recirculation due to vertical no-slip boundaries, two independently rotating rings are used at the vertical endcaps. This configuration reproduces setup used in laboratory experiments aiming to observe the MagnetoRotational Instability (MRI). Our 3D global simulations show that the nature of the bifurcation, the non-linear saturation, and the structure of axisymmetric MRI modes are significantly affected by the presence of boundaries. In addition, large scale non-axisymmetric modes are obtained when the applied field is sufficiently strong. We show that these modes are related to Kelvin-Helmoltz destabilization of a free Shercliff shear layer created by the combined action of the applied field and the rotating rings at the endcaps. Finally, we compare our numerical simulations to recent experimental results obtained in the Prince...

  11. Multiple Isotope Magneto Optical Trap from a single diode laser

    Science.gov (United States)

    Gomez, Eduardo; Valenzuela, Victor; Hamzeloui, Saeed; Gutierrez, Monica

    2013-05-01

    We present a simple design for a Dual Isotope Magneto Optical Trap. The system requires a single diode laser, a fiber modulator and a tapered amplifier to trap and completely control both 85Rb and 87Rb. We generate all the frequencies needed for trapping both species using the fiber intensity modulator. All the frequencies are amplified simultaneously with the tapered amplifier. The position and power of each frequency is now controlled independently on the RF rather than on the optical side. This introduces an enormous simplification for laser cooling that often requires an acousto-optic modulator for each frequency. The range of frequency changes is much bigger than what is available with acousto-optic modulators since in our case is determined by the modulator bandwidth (10 GHz). Additional isotopes can be simply added by including additional RF frequencies to the modulator and extra beams for other uses can be produced the same way. Support from CONACYT, PROMEP and UASLP.

  12. Auditory evoked field measurement using magneto-impedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K., E-mail: o-kabou@echo.nuee.nagoya-u.ac.jp; Tajima, S.; Song, D.; Uchiyama, T. [Graduate School of Engineering, Nagoya University, Nagoya (Japan); Hamada, N.; Cai, C. [Aichi Steel Corporation, Tokai (Japan)

    2015-05-07

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  13. Global regularity for generalized Hall magneto-hydrodynamics systems

    Directory of Open Access Journals (Sweden)

    Renhui Wan

    2015-06-01

    Full Text Available In this article, we consider the tridimensional generalized Hall magneto-hydrodynamics (Hall-MHD system, with $(-\\Delta^\\alpha u$ and $(-\\Delta^\\beta b$. For $\\alpha\\ge 5/4$, $\\beta\\ge 7/4$, we obtain the global regularity of classical solutions. For $0<\\alpha<5/4$ and $1/2<\\beta<7/4$, with small data, the system also possesses global classical solutions. In addition, for the standard Hall-MHD system, $\\alpha=\\beta=1$, by adding a suitable condition, we give a positive answer to the open question in [3]. At last, we study the regularity criterions of generalized Hall-MHD system. In particular, we prove the regularity criterion in terms of horizontal gradient $\

  14. Active control of magneto-hydrodynamic instabilities in hot plasmas

    CERN Document Server

    2015-01-01

    During the past century, world-wide energy consumption has risen dramatically, which leads to a quest for new energy sources. Fusion of hydrogen atoms in hot plasmas is an attractive approach to solve the energy problem, with abundant fuel, inherent safety and no long-lived radioactivity.  However, one of the limits on plasma performance is due to the various classes of magneto-hydrodynamic instabilities that may occur. The physics and control of these instabilities in modern magnetic confinement fusion devices is the subject of this book. Written by foremost experts, the contributions will provide valuable reference and up-to-date research reviews for "old hands" and newcomers alike.

  15. Element-specific study of the coupled magneto-structural and magneto-electronic properties of CoNi nanoarrays

    Science.gov (United States)

    Yang, Chao-Yao; Tseng, Yuan-Chieh; Lin, Hong-Ji

    2013-04-01

    The magneto-structural (MS) and magneto-electronic (ME) effects, as well as their coupling relationship, were investigated in electroless-plated (EL) Co0.5Ni0.5 arrays treated by post N2 annealing and in situ field plating. Separately and combined, these two treatments have been widely employed to improve the properties of magnetic nanostructures. This work aimed to discriminate between treatments with respect to electronic and structural properties, and magnetic degrees of freedom of Co0.5Ni0.5 nanostructures. The field-plated sample exhibited a strong MS-ME coupling due to magneto-crystalline anisotropy (MCA), arising from a FCC (111) preferred orientation with lattice planes stacking orthogonally to the long axial direction of the arrays. A large coercivity was observed in this structure, arising from high magnetic stability. X-ray magnetic circular dichroism revealed that magnetization was enhanced primarily by Co magnetism, while the field-plated sample underwent a MS/ME transition with corresponding increase of the plating field. Conversely, the heat-treated sample comprised isotropically oriented nanocrystals approximately 20 ± 3 nm in diameter, coated with an oxidation layer (approximately 5 ± 2 nm thick). The absence of MCA in these samples ensured a weak MS-ME coupling. Although the Ni magnetization of heat-treated samples remained close to that of the field-plated sample, the Co constituent exhibited CoO and Co3O4 phases in addition to the metallic state. By contrast, the Co constituent of the field-plated sample was mainly metallic. The lack of MCA, combined with a complex Co magnetic state, appears responsible for the divergent macroscopic magnetic behaviors of the heat-treated and the field-plated samples. By isolating changes in local magnetic moments of Ni and Co, we gained a fundamental understanding of the effects of post-N2 annealing and field plating on CoNi. Such knowledge may assist researches in improving the magnetic properties of

  16. Neuro-Fuzzy Computational Technique to Control Load Frequency in Hydro-Thermal Interconnected Power System

    Science.gov (United States)

    Prakash, S.; Sinha, S. K.

    2015-09-01

    In this research work, two areas hydro-thermal power system connected through tie-lines is considered. The perturbation of frequencies at the areas and resulting tie line power flows arise due to unpredictable load variations that cause mismatch between the generated and demanded powers. Due to rising and falling power demand, the real and reactive power balance is harmed; hence frequency and voltage get deviated from nominal value. This necessitates designing of an accurate and fast controller to maintain the system parameters at nominal value. The main purpose of system generation control is to balance the system generation against the load and losses so that the desired frequency and power interchange between neighboring systems are maintained. The intelligent controllers like fuzzy logic, artificial neural network (ANN) and hybrid fuzzy neural network approaches are used for automatic generation control for the two area interconnected power systems. Area 1 consists of thermal reheat power plant whereas area 2 consists of hydro power plant with electric governor. Performance evaluation is carried out by using intelligent (ANFIS, ANN and fuzzy) control and conventional PI and PID control approaches. To enhance the performance of controller sliding surface i.e. variable structure control is included. The model of interconnected power system has been developed with all five types of said controllers and simulated using MATLAB/SIMULINK package. The performance of the intelligent controllers has been compared with the conventional PI and PID controllers for the interconnected power system. A comparison of ANFIS, ANN, Fuzzy and PI, PID based approaches shows the superiority of proposed ANFIS over ANN, fuzzy and PI, PID. Thus the hybrid fuzzy neural network controller has better dynamic response i.e., quick in operation, reduced error magnitude and minimized frequency transients.

  17. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation

    Science.gov (United States)

    Hailong, Zhang; Enrong, Wang; Fuhong, Min; Ning, Zhang

    2016-03-01

    The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc-Wen force-velocity (F-v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. Projects supported by the National Natural Science Foundation of China (Grant Nos. 51475246, 51277098, and 51075215), the Research Innovation Program for College Graduates of Jiangsu Province China (Grant No. KYLX15 0725), and the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131402).

  18. Integration of Magneto-Optical Materials for Novel Optical Devices & Magnetophotonic Crystals Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This work proposes to capitalize on our Phase I success in monolithically integrating magneto-optic and magnetic materials with semiconductor platforms in order to...

  19. MAGNETO-ABRASIVE MACHINING OF SURFACES FORMED BY ELECTROMAGNET SURFACING WITH PLASTIC DEFORMATION

    Directory of Open Access Journals (Sweden)

    Zh. A. Mrochek

    2011-01-01

    Full Text Available The paper presents investigation results pertaining to magneto-abrasive machining of product surfaces formed by electromagnet surfacing with a plastic deformation of P6M5K5 powder. 

  20. Magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy

    Science.gov (United States)

    Ning, Keyu; Liu, Houfang; Ju, Zhenyi; Fang, Chi; Wan, Caihua; Cheng, Jinglei; Liu, Xiao; Li, Linsen; Feng, Jiafeng; Wei, Hongxiang; Han, Xiufeng; Yang, Yi; Ren, Tian-Ling

    2017-01-01

    As one invigorated filed of spin caloritronics combining with spin, charge and heat current, the magneto-Seebeck effect has been experimentally and theoretically studied in spin tunneling thin films and nanostructures. Here we analyze the tunnel magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy (p-MTJs) under various measurement temperatures. The large tunnel magneto-Seebeck (TMS) ratio up to -838.8% for p-MTJs at 200 K is achieved, with Seebeck coefficient S in parallel and antiparallel states of 6.7 mV/K and 62.9 mV/K, respectively. The temperature dependence of the tunnel magneto-Seebeck can be attributed to the contributing transmission function and electron states at the interface between CoFeB electrode and MgO barrier.

  1. Magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy

    Directory of Open Access Journals (Sweden)

    Keyu Ning

    2017-01-01

    Full Text Available As one invigorated filed of spin caloritronics combining with spin, charge and heat current, the magneto-Seebeck effect has been experimentally and theoretically studied in spin tunneling thin films and nanostructures. Here we analyze the tunnel magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy (p-MTJs under various measurement temperatures. The large tunnel magneto-Seebeck (TMS ratio up to −838.8% for p-MTJs at 200 K is achieved, with Seebeck coefficient S in parallel and antiparallel states of 6.7 mV/K and 62.9 mV/K, respectively. The temperature dependence of the tunnel magneto-Seebeck can be attributed to the contributing transmission function and electron states at the interface between CoFeB electrode and MgO barrier.

  2. High magneto-optical characteristics of Holmium-doped terbium gallium garnet crystal.

    Science.gov (United States)

    Chen, Zhe; Yang, Lei; Wang, Xiangyong; Yin, Hang

    2016-06-01

    Magneto-optical characteristics of a new magneto-active material, (Tb(1-x)Hox)3Ga5O12 crystal, have been grown by the Czochralski (Cz) method. A high value of the Verdet constant was obtained at room temperature-namely, 214.9 and 77.8  rad·m-1 T-1 for 632.8 and 1064 nm, respectively. The Verdet constant of the Ho-doped terbium gallium garnet crystal at 1064 nm is about 2 times higher than that of terbium gallium garnet crystal. High value of magneto-optical figure-of-merit makes it an attractive next-generation magneto-optics material for high-power Faraday isolators.

  3. [Magneto-laser therapy of chronic gastritis in children and adolescents].

    Science.gov (United States)

    Zviagin, A A; Nikolaenko, E A

    2008-01-01

    The efficiency of transcutaneous magneto-laser treatment as a component of combined therapy of chronic gastritis in children and adolescents (aged 5-17 years) was compared with that of pharmacotherapy and low-intensity laser therapy. The patients were allocated to three groups of 25 persons each. Patients of group 1 were given only drug therapy, those in group 2 were treated with pharmaceuticals and low-intensity laser therapy. The patients comprising group 3 were subjected to the action of magneto-laser radiation. Magneto-laser therapy was shown to result in a significantly more expressed improvement of clinical and morphological characteristics of the patients compared with pharmacotherapy alone. There was no significant difference between effects of magneto-laser and low-intensity laser radiation.

  4. Determination of magneto-optical constant of Fe films with weak measurements

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaodong; Hu, Dejiao; Du, Jinglei; Gao, Fuhua; Zhang, Zhiyou, E-mail: zhangzhiyou@scu.edu.cn [Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Zhou, Xinxing; Luo, Hailu, E-mail: hailuluo@hnu.edu.cn [Laboratory for Spin Photonics, College of Physics and Electronic Science, Hunan University, Changsha 410082 (China)

    2014-09-29

    In this letter, a detecting method for the magneto-optical constant is presented by using weak measurements. The photonic spin Hall effect (PSHE), which manifests itself as spin-dependent splitting, is introduced to characterize the magneto-optical constant, and a propagation model to describe the quantitative relation between the magneto-optical constant and the PSHE is established. According to the amplified shift of the PSHE detected by weak measurements, we determinate the magneto-optical constant of the Fe film sample. The Kerr rotation is measured via the standard polarimetry method to verify the rationality and feasibility of our method. These findings may provide possible applications in magnetic physics research.

  5. A magneto-electro-optical effect in a plasmonic nanowire material

    Science.gov (United States)

    Valente, João; Ou, Jun-Yu; Plum, Eric; Youngs, Ian J.; Zheludev, Nikolay I.

    2015-01-01

    Electro- and magneto-optical phenomena play key roles in photonic technology enabling light modulators, optical data storage, sensors and numerous spectroscopic techniques. Optical effects, linear and quadratic in external electric and magnetic field are widely known and comprehensively studied. However, optical phenomena that depend on the simultaneous application of external electric and magnetic fields in conventional media are barely detectable and technologically insignificant. Here we report that a large reciprocal magneto-electro-optical effect can be observed in metamaterials. In an artificial chevron nanowire structure fabricated on an elastic nano-membrane, the Lorentz force drives reversible transmission changes on application of a fraction of a volt when the structure is placed in a fraction-of-tesla magnetic field. We show that magneto-electro-optical modulation can be driven to hundreds of thousands of cycles per second promising applications in magneto-electro-optical modulators and field sensors at nano-tesla levels. PMID:25906761

  6. Determination of magneto-optical constant of Fe films with weak measurements

    Science.gov (United States)

    Qiu, Xiaodong; Zhou, Xinxing; Hu, Dejiao; Du, Jinglei; Gao, Fuhua; Zhang, Zhiyou; Luo, Hailu

    2014-09-01

    In this letter, a detecting method for the magneto-optical constant is presented by using weak measurements. The photonic spin Hall effect (PSHE), which manifests itself as spin-dependent splitting, is introduced to characterize the magneto-optical constant, and a propagation model to describe the quantitative relation between the magneto-optical constant and the PSHE is established. According to the amplified shift of the PSHE detected by weak measurements, we determinate the magneto-optical constant of the Fe film sample. The Kerr rotation is measured via the standard polarimetry method to verify the rationality and feasibility of our method. These findings may provide possible applications in magnetic physics research.

  7. Tunable Fano resonance and magneto-optical response in magnetoplasmonic structure fabricated by pure ferromagnetic metals

    Science.gov (United States)

    Chen, Leyi; Gao, Jinlong; Xia, Wenbin; Zhang, Shaoyin; Tang, Shaolong; Zhang, Weiyi; Li, Daoyong; Wu, Xiaoshan; Du, Youwei

    2016-06-01

    The developments in nanophotonics demand more efficient and delicate control of light. It has recently been proposed to achieve this goal by combining plasmonics and magneto-optics in so-called magnetoplasmonic nanostructures. However, significant challenges still remain because of the difficulty in the design of spectrally tunable systems exhibiting novel plasmonic and magneto-optical responses simultaneously. Here we report a magnetoplasmonic structure which consists of a two-dimensional nickel nanodisk array on top of a cobalt film substrate. We demonstrate that a tunable Fano resonance can be generated in this system with properly designed geometric parameters. Furthermore, the magneto-optical Kerr responses in this system can be manipulated due to the concerted actions of free electrons in the resonance. Our results reveal the possibility of fabricating large-area magnetoplasmonic structures by a simple, mass-producible method, and tuning the plasmonic and magneto-optical responses simultaneously.

  8. Generalized scattering-matrix approach for magneto-optics in periodically patterned multilayer systems

    CERN Document Server

    Caballero, B; Cuevas, J C

    2012-01-01

    We present here a generalization of the scattering-matrix approach for the description of the propagation of electromagnetic waves in nanostructured magneto-optical systems. Our formalism allows us to describe all the key magneto-optical effects in any configuration in periodically patterned multilayer structures. The method can also be applied to describe periodic multilayer systems comprising materials with any type of optical anisotropy. We illustrate the method with the analysis of a recent experiment in which the transverse magneto-optical Kerr effect was measured in a Fe film with a periodic array of subwavelength circular holes. We show, in agreement with the experiments, that the excitation of surface plasmon polaritons in this system leads to a resonant enhancement of the transverse magneto-optical Kerr effect.

  9. Magneto-thermoelasticity with thermoelectric properties and fractional derivative heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ezzat, Magdy A., E-mail: maezzat2000@yahoo.co [Department of Mathematics, Faculty of Education, Alexandria University (Egypt)

    2011-01-01

    In this work, a new model of the magneto-thermoelasticity theory has been constructed in the context of a new consideration of heat conduction with fractional derivative. A one-dimensional application for a conducting half-space of thermoelectric elastic material, which is thermally shocked in the presence of a magnetic field, has been solved using Laplace transform and state-space techniques (Ezzat, 2008). According to the numerical results and its graphs, a conclusion about the new theory of magneto-thermoelasticity has been constructed. The theories of coupled magneto-thermoelasticity and of generalized magneto-thermoelasticity with one relaxation time follow as limited cases. The result provides a motivation to investigate conducting thermoelectric materials as a new class of applicable materials.

  10. Magneto-rheological elastomer (MRE) based composite structures for micro-vibration control

    Institute of Scientific and Technical Information of China (English)

    YQ Ni; ZG Ying; ZH Chen

    2010-01-01

    Magneto-theological elastomers (MREs) are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square (RMS) velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-hased structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.

  11. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER).

    Science.gov (United States)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-14

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the (19)F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  12. Semi-active engine mount design using auxiliary magneto-rheological fluid compliance chamber

    Science.gov (United States)

    Mansour, H.; Arzanpour, S.; Golnaraghi, M. F.; Parameswaran, A. M.

    2011-03-01

    Engine mounts are used in the automotive industry to isolate engine and chassis by reducing the noise and vibration imposed from one to the other. This paper describes modelling, simulation and design of a semi-active engine mount that is designed specifically to address the complicated vibration pattern of variable displacement engines (VDE). The ideal isolation for VDE requires the stiffness to be switchable upon cylinder activation/deactivation operating modes. In order to have a modular design, the same hydraulic engine mount components are maintained and a novel auxiliary magneto-rheological (MR) fluid chamber is developed and retrofitted inside the pumping chamber. The new compliance chamber is a controllable pressure regulator, which can effectively alter the dynamic performance of the mount. Switching between different modes happens by turning the electrical current to the MR chamber magnetic coil on and off. A model has been developed for the passive hydraulic mount and then it is extended to include the MR auxiliary chamber as well. A proof-of-concept prototype of the design has been fabricated which validates the mathematical model. The results demonstrate unique capability of the developed semi-active mount to be used for VDE application.

  13. Experimental Studies of the Electrothermal and Magneto-Rayleigh Taylor Instabilities on Thin Metal Foil Ablations

    Science.gov (United States)

    Steiner, Adam; Yager-Elorriaga, David; Patel, Sonal; Jordan, Nicholas; Gilgenbach, Ronald; Lau, Y. Y.

    2015-11-01

    The electrothermal instability (ETI) and magneto-Rayleigh Taylor instability (MRT) are important in the implosion of metallic liners, such as magnetized liner implosion fusion (MagLIF). The MAIZE linear transformer driver (LTD) at the University of Michigan generates 200 ns risetime-current pulses of 500 to 600 kA into Al foil liners to study plasma instabilities and implosion dynamics, most recently MRT growth on imploding cylindrical liners. A full circuit model of MAIZE, along with I-V measurements, yields time-resolved load inductance. This has enabled measurements of an effective current-carrying radius to determine implosion velocity and plasma-vacuum interface acceleration. Measurements are also compared to implosion data from 4-time-frame laser shadowgraphy. Improved resolution measurements on the laser shadowgraph system have been used to examine the liner interface early in the shot to examine surface perturbations resulting from ETI for various seeding conditions. Fourier analysis examines the growth rates of wavelength bands of these structures to examine the transition from ETI to MRT. This work was supported by the U.S. DoE through award DE-SC0012328. S.G. Patel is supported by Sandia National Labs. D.A. Yager is supported by NSF fellowship grant DGE 1256260.

  14. Magneto hydrodynamics simulations of pulsed high density plasmas in electromagnetic guns

    Science.gov (United States)

    Sitaraman, Hariswaran; Raja, Laxminarayan

    2011-10-01

    Electromagnetic guns are a class of devices which uses the Lorentz force to accelerate bulk plasma/conducting solids to velocities ~ km/s. This idea has been widely used in electromagnetic rail guns and in space propulsion systems. The electrically conducting region is typically a pulsed high density thermal plasma which interacts with the bounding solid surface resulting in ablation and materials chemical degradation. We perform a numerical modeling study of the plasma in an electromagnetic gun to understand the discharge physics and in particular study the plasma-surface interactions. The resistive Magneto hydrodynamics (MHD) equations which include the mass, momentum and energy equations for a conducting fluid along with the Maxwell's equations is used for this study. These equations constitute a stiff system with strong coupling between fluid dynamics and electromagnetics. The equations are solved on an unstructured mesh using a cell-centered finite volume formulation. Details of important species in the plasma and the particle and energy flux distribution at the solid boundaries are presented and the consequent plasma-surface interactions under varying operating conditions are discussed.

  15. NONLINEAR EVOLUTION OF THE RADIATION-DRIVEN MAGNETO-ACOUSTIC INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Rodrigo; Socrates, Aristotle [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2013-04-20

    We examine the nonlinear development of unstable magnetosonic waves driven by a background radiative flux-the radiation-driven magneto-acoustic instability (RMI, a.k.a. the ''photon bubble'' instability). The RMI may serve as a persistent source of density, radiative flux, and magnetic field fluctuations in stably stratified, optically thick media. The conditions for instability are present in a variety of astrophysical environments and do not require the radiation pressure to dominate or the magnetic field to be strong. Here, we numerically study the saturation properties of the RMI, covering three orders of magnitude in the relative strength of radiation, magnetic field, and gas energies. Two-dimensional, time-dependent radiation-magnetohydrodynamic simulations of local, stably stratified domains are conducted with Zeus-MP in the optically thick, highly conducting limit. Our results confirm the theoretical expectations of Blaes and Socrates in that the RMI operates even in gas-pressure-dominated environments that are weakly magnetized. The saturation amplitude is a monotonically increasing function of the ratio of radiation to gas pressure. Keeping this ratio constant, we find that the saturation amplitude peaks when the magnetic pressure is comparable to the radiation pressure. We discuss the implications of our results for the dynamics of magnetized stellar envelopes, where the RMI should act as a source of sub-photospheric perturbations.

  16. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

    Science.gov (United States)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-01

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  17. High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

    Science.gov (United States)

    Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

    2017-01-01

    Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

  18. The Front-End Readout as an Encoder IC for Magneto-Resistive Linear Scale Sensors

    Science.gov (United States)

    Tran, Trong-Hieu; Chao, Paul Chang-Po; Chien, Ping-Chieh

    2016-01-01

    This study proposes a front-end readout circuit as an encoder chip for magneto-resistance (MR) linear scales. A typical MR sensor consists of two major parts: one is its base structure, also called the magnetic scale, which is embedded with multiple grid MR electrodes, while another is an “MR reader” stage with magnets inside and moving on the rails of the base. As the stage is in motion, the magnetic interaction between the moving stage and the base causes the variation of the magneto-resistances of the grid electrodes. In this study, a front-end readout IC chip is successfully designed and realized to acquire temporally-varying resistances in electrical signals as the stage is in motions. The acquired signals are in fact sinusoids and co-sinusoids, which are further deciphered by the front-end readout circuit via newly-designed programmable gain amplifiers (PGAs) and analog-to-digital converters (ADCs). The PGA is particularly designed to amplify the signals up to full dynamic ranges and up to 1 MHz. A 12-bit successive approximation register (SAR) ADC for analog-to-digital conversion is designed with linearity performance of ±1 in the least significant bit (LSB) over the input range of 0.5–2.5 V from peak to peak. The chip was fabricated by the Taiwan Semiconductor Manufacturing Company (TSMC) 0.35-micron complementary metal oxide semiconductor (CMOS) technology for verification with a chip size of 6.61 mm2, while the power consumption is 56 mW from a 5-V power supply. The measured integral non-linearity (INL) is −0.79–0.95 LSB while the differential non-linearity (DNL) is −0.68–0.72 LSB. The effective number of bits (ENOB) of the designed ADC is validated as 10.86 for converting the input analog signal to digital counterparts. Experimental validation was conducted. A digital decoder is orchestrated to decipher the harmonic outputs from the ADC via interpolation to the position of the moving stage. It was found that the displacement measurement

  19. The Front-End Readout as an Encoder IC for Magneto-Resistive Linear Scale Sensors.

    Science.gov (United States)

    Tran, Trong-Hieu; Chao, Paul Chang-Po; Chien, Ping-Chieh

    2016-09-02

    This study proposes a front-end readout circuit as an encoder chip for magneto-resistance (MR) linear scales. A typical MR sensor consists of two major parts: one is its base structure, also called the magnetic scale, which is embedded with multiple grid MR electrodes, while another is an "MR reader" stage with magnets inside and moving on the rails of the base. As the stage is in motion, the magnetic interaction between the moving stage and the base causes the variation of the magneto-resistances of the grid electrodes. In this study, a front-end readout IC chip is successfully designed and realized to acquire temporally-varying resistances in electrical signals as the stage is in motions. The acquired signals are in fact sinusoids and co-sinusoids, which are further deciphered by the front-end readout circuit via newly-designed programmable gain amplifiers (PGAs) and analog-to-digital converters (ADCs). The PGA is particularly designed to amplify the signals up to full dynamic ranges and up to 1 MHz. A 12-bit successive approximation register (SAR) ADC for analog-to-digital conversion is designed with linearity performance of ±1 in the least significant bit (LSB) over the input range of 0.5-2.5 V from peak to peak. The chip was fabricated by the Taiwan Semiconductor Manufacturing Company (TSMC) 0.35-micron complementary metal oxide semiconductor (CMOS) technology for verification with a chip size of 6.61 mm², while the power consumption is 56 mW from a 5-V power supply. The measured integral non-linearity (INL) is -0.79-0.95 LSB while the differential non-linearity (DNL) is -0.68-0.72 LSB. The effective number of bits (ENOB) of the designed ADC is validated as 10.86 for converting the input analog signal to digital counterparts. Experimental validation was conducted. A digital decoder is orchestrated to decipher the harmonic outputs from the ADC via interpolation to the position of the moving stage. It was found that the displacement measurement error is within

  20. The Front-End Readout as an Encoder IC for Magneto-Resistive Linear Scale Sensors

    Directory of Open Access Journals (Sweden)

    Trong-Hieu Tran

    2016-09-01

    Full Text Available This study proposes a front-end readout circuit as an encoder chip for magneto-resistance (MR linear scales. A typical MR sensor consists of two major parts: one is its base structure, also called the magnetic scale, which is embedded with multiple grid MR electrodes, while another is an “MR reader” stage with magnets inside and moving on the rails of the base. As the stage is in motion, the magnetic interaction between the moving stage and the base causes the variation of the magneto-resistances of the grid electrodes. In this study, a front-end readout IC chip is successfully designed and realized to acquire temporally-varying resistances in electrical signals as the stage is in motions. The acquired signals are in fact sinusoids and co-sinusoids, which are further deciphered by the front-end readout circuit via newly-designed programmable gain amplifiers (PGAs and analog-to-digital converters (ADCs. The PGA is particularly designed to amplify the signals up to full dynamic ranges and up to 1 MHz. A 12-bit successive approximation register (SAR ADC for analog-to-digital conversion is designed with linearity performance of ±1 in the least significant bit (LSB over the input range of 0.5–2.5 V from peak to peak. The chip was fabricated by the Taiwan Semiconductor Manufacturing Company (TSMC 0.35-micron complementary metal oxide semiconductor (CMOS technology for verification with a chip size of 6.61 mm2, while the power consumption is 56 mW from a 5-V power supply. The measured integral non-linearity (INL is −0.79–0.95 LSB while the differential non-linearity (DNL is −0.68–0.72 LSB. The effective number of bits (ENOB of the designed ADC is validated as 10.86 for converting the input analog signal to digital counterparts. Experimental validation was conducted. A digital decoder is orchestrated to decipher the harmonic outputs from the ADC via interpolation to the position of the moving stage. It was found that the displacement