Journal articles on the topic 'Running magnetization'
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1
Kudasov, Yuri, and Roman Kozabaranov. "The origin of fine structure in magnetization curve of αCoV2O6." EPJ Web of Conferences 185 (2018): 03002. http://dx.doi.org/10.1051/epjconf/201818503002.
Abstract:
Multiple field-induced plateaus in αCoV2O6 at low temperatures were revealed earlier by M. Lenertz et al. [J. Phys. Chem. C 115, 17190 (2011)] and carefully investigated recently by M. Nandi and P. Mandal [J. Appl. Phys. 119, 133904 (2016)]. Four equidistant steps were observed in the magnetization curve. We present a model to describe this phenomenon. A magnetic structure of this substance is formed by highly anisotropic triangular lattice of Ising chains running along the b axis. Due to a three-fold degeneracy of three-sublattice magnetic ordering, domain boundaries appear. Their transformation under magnetic field variation leads to two additional steps in the 1/3 magnetization plateau and gives rise to complex magnetic behavior observed experimentally. The domain structure in αCoV2O6 occurs to be strongly anisotropic because a lifetime of the metastable states depends greatly on the configuration orientation. A strong dependence of the magnetization curve on magnetic field sweep time is predicted.
2
Zeng, Jei-Wei, Zhi-Qiang Long, Jingfang Ding, and Xiao Liang. "Measurement of the residual stress for the bogie frame of maglev vehicle based on barkhausen effect." Transportation Systems and Technology 4, no. 3 suppl. 1 (November 19, 2018): 289–97. http://dx.doi.org/10.17816/transsyst201843s1289-297.
Abstract:
Background: The effect of residual stress resulted from the manufacturing process on the performance of bogie frame has been attracting more and more attention with the increasing of running speed of maglev vehicle, which could develop cracks on the frame and compromise the operational safety.
Aim: It is necessary to determine and understand the distribution rules of residual stress on the bogie frames.
Methods: Barkhausen effect is one of the effective methods used to measure residual stress.
Results: This paper presents a experiment system designed for residual stress detection and the principle of electromagnetic stress detection is expounded, finite element simulation analysis on magnetization device is carried out, and the effect of magnetization under different excitation conditions is analyzed.
Conclusion: The feasibility of the online magnetic detection method of internal stresses in bogie frame is verified through the simulation, which would provided the basis for bogie frames internal stresses detection.
3
Magat, Julie, Arnaud Fouillet, Marion Constantin, Kylian Haliot, Jérôme Naulin, Dounia El Hamrani, David Benoist, et al. "3D magnetization transfer (MT) for the visualization of cardiac free-running Purkinje fibers: an ex vivo proof of concept." Magnetic Resonance Materials in Physics, Biology and Medicine 34, no. 4 (January 23, 2021): 605–18. http://dx.doi.org/10.1007/s10334-020-00905-w.
Abstract:
Abstract Objectives We investigate the possibility to exploit high-field MRI to acquire 3D images of Purkinje network which plays a crucial role in cardiac function. Since Purkinje fibers (PF) have a distinct cellular structure and are surrounded by connective tissue, we investigated conventional contrast mechanisms along with the magnetization transfer (MT) imaging technique to improve image contrast between ventricular structures of differing macromolecular content. Methods Three fixed porcine ventricular samples were used with free-running PFs on the endocardium. T1, T2*, T2, and M0 were evaluated on 2D slices for each sample at 9.4 T. MT parameters were optimized using hard pulses with different amplitudes, offset frequencies and durations. The cardiac structure was assessed through 2D and 3D T1w images with isotropic resolutions of 150 µm. Histology, immunofluorescence, and qPCR were performed to analyze collagen contents of cardiac tissue and PF. Results An MT preparation module of 350 ms duration inserted into the sequence with a B1 = 10 µT and frequency offset = 3000 Hz showed the best contrast, approximately 0.4 between PFs and myocardium. Magnetization transfer ratio (MTR) appeared higher in the cardiac tissue (MTR = 44.7 ± 3.5%) than in the PFs (MTR = 25.2 ± 6.3%). Discussion MT significantly improves contrast between PFs and ventricular myocardium and appears promising for imaging the 3D architecture of the Purkinje network.
4
Arauzo, Ana, Elena Bartolomé, Javier Luzón, Pablo Alonso, Angelica Vlad, Maria Cazacu, Mirela Zaltariov, Sergiu Shova, Juan Bartolomé, and Constantin Turta. "Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H2O}n MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs." Molecules 26, no. 18 (September 16, 2021): 5626. http://dx.doi.org/10.3390/molecules26185626.
Abstract:
We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H2O}n (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4`-azopyridine) (1) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the bc plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the c-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the c crystallographic axis, which accommodate the disordered solvate molecules. The Co(II) is six-coordinated in a distorted octahedral geometry, where the equatorial plane is occupied by four carboxylate oxygen atoms. Two nitrogen atoms from APy ligands are coordinated in apical positions. The single-ion magnetic anisotropy has been determined by low temperature EPR and magnetization measurements on an isostructural compound {[Zn0.8Co0.2CxAPy]·1.5 CH3OH}n (2). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C2V main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the ab initio calculations of the g-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a S* = 1/2 magnetic dimer model with anisotropic antiferromagnetic interaction. The magnetic dimer exhibits slow relaxation of the magnetization (SMM) below 6 K in applied field, with a tlf ≈ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with U/kB = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction.
5
Zhou, Zhou, Xiuheng Zhang, Ran Deng, Lu Han, Meng Zhou, Zhuangzhuang Ma, Xiangdong Chang, and Yuxing Peng. "Research on a Wire Rope Breakage Detection Device for High-Speed Operation Based on the Multistage Excitation Principle." Sensors 23, no. 23 (November 21, 2023): 9298. http://dx.doi.org/10.3390/s23239298.
Abstract:
Wire rope breakage, as damage easily produced during the service period of wire rope, is an important factor affecting the safe operation of elevators. Especially in the high-speed elevator operation process, the problem of magnetization unsaturation caused by speed effects can easily lead to deformation of the magnetic flux leakage detection signal, thereby affecting the accuracy and reliability of wire breakage quantitative detection. Therefore, this article focuses on the problem that existing wire rope detection methods cannot perform non-destructive testing on high-speed elevator wire ropes and conducts design and experimental research on a high-speed running wire rope breakage detection device based on the principle of multi-stage excitation. The main research content includes simulation research on the multistage excitation, structural design, and simulation optimization of open–close copper sheet magnetizers and the building of a detection device for wire rope breakage detection experimental research. The simulation and experimental results show that the multistage magnetization method can effectively solve the problem of magnetization unsaturation caused by the velocity effect. The multistage excitation device has a good wire breakage recognition effect for speeds less than or equal to 3 m/s. It can detect magnetic leakage signals with a minimum of four broken wires and has good detection accuracy. It is a new and effective wire breakage detection device for high-speed elevator wire rope, providing important technical support for the safe and reliable operation of high-speed elevators.
6
Warzecha, Adam, and Witold Mazgaj. "Effects Generated by the Magnetic Core Anisotropy of an Induction Motor." Energies 13, no. 9 (May 1, 2020): 2189. http://dx.doi.org/10.3390/en13092189.
Abstract:
A theoretical analysis enables effects generated by the magnetic core anisotropy of an induction motor to be determined qualitatively. Relationships formulated between currents and magnetic flux linkages that are associated with three-phase stator windings enable the qualitative determination of spectra of currents or voltages of a typical induction motor. These relationships account for nonlinear and anisotropic magnetization characteristics of the motor core, both during idle running and motor starting. Based on these relationships, components of the amplitude Fourier spectra of symmetrical components of currents or voltages, which are useful in the diagnostics of stator or rotor core anisotropy, were selected. Field calculations were performed for the core of a two-pole 5.5 kW motor supplied by three-phase sinusoidal currents. The components of the induced voltage Fourier spectra in both the idle running and short-circuit state were similar to analogous components predicted based on theoretical studies. The components occurring in the spectra, which were obtained based on field calculations, were distinguished in the measured spectra of the symmetrical components of the phase currents. These components were applied to estimate representative current signal levels in the diagnostics of motor core anisotropy. Relative values of these signals did not exceed 60 dB; however, they were significant for assessing the internal asymmetry level of the motor stator or rotor core. The results of laboratory measurements confirmed the results of the theoretical analysis.
7
Kovintavewat, Piya, and Santi Koonkarnkhai. "Baseline Popping Detection and Correction Algorithms for Perpendicular Magnetic Recording System." Advanced Materials Research 979 (June 2014): 50–53. http://dx.doi.org/10.4028/www.scientific.net/amr.979.50.
Abstract:
Hard disk drives (HDDs) employ the magneto-resistive (MR) head to sense the change in magnetic flux via the transitions of magnetization pattern, resulting in a readback signal. Thus, head instability plays an important role on the reliability of HDDs because it can deteriorate the system performance considerably. Baseline popping (BLP) is one of the crucial problems caused by the head instability, whose effect can distort the readback signal to the extent of causing a sector read failure. This paper proposes three BLP detection and correction algorithms for a perpendicular magnetic recording (PMR) system. Specifically, to suppress the BLP effect experienced in the readback signal, the first algorithm is based on an averaging filter and a threshold detector; the second one relies on the estimated BLP signal obtained from a linear curve fitting technique; and finally the third one uses two sequence detectors running in parallel. Experimental results indicate that the third algorithm performs better than the other schemes because it can detect and correct the BLP better than the others, especially when the peak BLP amplitude is large.
8
Patel, Nimeshchandra S., Dipak Vakharia, and Gunamani Deheri. "Hydrodynamic journal bearing lubricated with a ferrofluid." Industrial Lubrication and Tribology 69, no. 5 (September 4, 2017): 754–60. http://dx.doi.org/10.1108/ilt-08-2016-0179.
Abstract:
Purpose This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system. Design/methodology/approach This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions. Findings The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running. Originality/value This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.
9
Shvanskaya, Larisa, Olga Yakubovich, Polina Krikunova, Evgeny Ovchenkov, and Alexander Vasiliev. "Chain caesium borophosphates with B:P ratio 1:2: synthesis, structure relationships and low-temperature thermodynamic properties." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 6 (November 23, 2019): 1174–85. http://dx.doi.org/10.1107/s2052520619013763.
Abstract:
Three caesium-bearing borophosphates, Cs[BP2O6(OH)2] (I), Cs0.51Mn1.17(H2O)2[BP2O8]·0.45H2O (II) and CsMn[BP2O8(OH)] (III), were synthesized by a hydrothermal method at 473–523 K. Their crystal structures have been studied by means of single-crystal X-ray diffraction; all three structures comprise borophosphate chain anions with a B:P ratio of 1:2. The unique construction of (I) is based on four-membered-ring chains running parallel to the [010] direction. These protonated borophosphate chains are linked via hydrogen-bond interactions to form a 3D framework with caesium cations incorporated. (II) is the first Cs and Mn2+,Mn3+ member of a known family characterized by [BP2O8]∞ helical chains running along [001]. These chains are connected through MnO4(H2O)2 octahedra to form a 3D framework. The caesium cations are disordered over two independent positions in the channels, which they occupy together with water molecules. An additional MnO2(H2O)3 bipyramid statistically shares a common edge and two corners with three main Mn octahedra to form tetrameric clusters. The topological relation between the chain anionic fragments of (I) and (II) as well as the structural relation between (I) and previously studied boro- and berillophosphates are discussed. Compound (III) presents the first Mn member of the A I M III[BP2O8(OH)] family and is characterized by a 3D framework built by open-branched borophosphate chains and MnO5 semi-octahedra sharing vertices. The measurements of thermodynamic properties, i.e. magnetization M and specific heat C p, to 2 K and 30 T, provide evidence that (II) orders antiferromagnetically at the Néel temperature T N = 4.6 K and exhibits a plateau-like feature under the action of an external magnetic field accompanied by a pronounced magnetocaloric effect.
10
Polar, A., J. E. Indacochea, M. L. Wang, V. Singh, and G. Lloyd. "Measurement and Microstructural Evaluation of Creep-Induced Changes in Magnetic Properties of a 410 Stainless Steel." Journal of Engineering Materials and Technology 126, no. 4 (October 1, 2004): 392–97. http://dx.doi.org/10.1115/1.1790542.
Abstract:
There is a compelling desire by power generating plants to continue running existing stations and components for several more years, despite many of them have surpassed their design service life. The idea is to avoid premature retirement, on the basis of the so-called design life, because actual useful life could often be well in excess of the design life. This can most readily be achieved by utilizing nondestructive monitoring methods to monitor the degradation of the microstructure, either when a station is down for maintenance or preferably when it is under operation. This study evaluates the use of quasi static hysteresis measurements as a possible procedure to evaluate creep in a 410 martensitic stainless steel, a material utilized in power plant components. The creep rupture tests were conducted at stresses of 100 and 200 MPa, temperatures of 500°C and 620°C, and the times varied between 48 and 120 hours. Following the creep tests all specimens were evaluated magnetically and then metallurgically by optical and scanning electron microscopy, x-ray diffraction (XRD) and by energy dispersive spectroscopy (EDS). The microstructural changes were compared with the magnetization changes. It was determined that the changes in the hysteresis curves were clearly detectable and correlated with the creep-induced damage.
11
Fan, J., and Y. Lee. "Dynamic measurement of magnetic characteristics of switched reluctance motor." Electrical Engineering & Electromechanics, no. 2 (March 5, 2023): 3–6. http://dx.doi.org/10.20998/2074-272x.2023.2.01.
Abstract:
Introduction. Switched reluctance motor (SRM) is a type of electric motor featuring nonlinear magnetic characteristics. The flux linkage or inductance profile of SRM is usually required for the purpose of high control performance, and can be normally obtained through conventional static test by using DC or AC method when the rotor is locked. Problem. However, it is not practical to use the conventional method of measurement when the specific apparatus for locking the rotor is unavailable. Besides, due to the magnetic nonlinearity of SRM, the saturation effect makes it difficult to obtain the saturated magnetic characteristics, and the conventional static AC test fails to address this problem. Novelty. In this paper, a dynamic measurement method of the magnetization curves of SRM is proposed which allows the measurement take place while the motor is running with load. Methodology. Based on the conventional static AC test, the proposed measurement handles the saturation problem successfully by introducing a DC offset in the high frequency AC voltage. Phase inductance with different rotor positions and currents can be obtained by analyzing simple equivalent circuit. Practical value. Simulation is conducted in MATLAB/Simulink environment and the results have verified that the proposed dynamic measurement can effectively obtain the magnetic characteristics of SRM.
12
Jakubcová, Petra, Dirk Johrendt, Peter Sebastian, Sudhindra Rayaprol, and Rainer Pöttgen. "Structure, Magnetic Properties and 151Eu, 119Sn Mössbauer Spectroscopy of Eu5Sn3S12 and Eu4LuSn3S12." Zeitschrift für Naturforschung B 62, no. 1 (January 1, 2007): 5–14. http://dx.doi.org/10.1515/znb-2007-0102.
Abstract:
Eu5Sn3S12 and Eu4LuSn3S12 were synthesized and their structures refined from single crystal data (Pmc21, Eu5Sn3S12: a = 3.908(1), b = 20.115(4), c = 11.451(2) Å ; wR2 = 0.0519 for 3048 F2 and 122 parameters; Eu4LuSn3S12: a = 3.920(1), b = 20.132(4), c = 11.459(2) Å ; wR2 = 0.0737 for 3298 F2 and 122 parameters). The structures contain one-dimensional chains of edge-sharing SnS2S4/2 octahedra and corner-sharing SnS3S2/2 trigonal bipyramids, running parallel to [100]. Five europium sites are seven- or eightfold coordinated by sulfur atoms. Lutetium atoms in Eu4LuSn3S12 show a strong site preference for one of the two Eu3+ positions of Eu5Sn3S12 and no structural disorder was observed. Both compounds show static mixed valence according to Eu2+3 Eu3+2 Sn4+3 S2−12 and Eu2+3 Eu3+Lu3+Sn4+3 S2−12 , which was confirmed by temperature dependent magnetic susceptibility measurements. The experimental magnetic moments of 14.6(1) (Eu5Sn3S12) and 14.1(1) (Eu4LuSn3S12) μB/f.u. indicate that each of the two sulfides contains three divalent europium atoms per formula unit. Magnetic ordering for Eu5Sn3S12 and Eu4LuSn3S12 sets in below 5 and 3 K, respectively. Both sulfides show metamagnetic or spin-flip transitions in the magnetization curves at 3 K (2 K) with full saturation of the europium magnetic moments at 3 K (2 K) and 80 kOe. 151Eu Mössbauer spectra fully confirm the Eu2+ and Eu3+ site occupancies. At 4.2 K an increase in line width indicates small hyperfine fields at the europium nuclei.
13
Siegfried, S. A., E. V. Altynbayev, N. M. Chubova, A. Heinemann, V. A. Dyadkin, E. V. Moskvin, D. Menzel, et al. "Spin chirality is flipped in transition-metal monogermanides." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1546. http://dx.doi.org/10.1107/s2053273314084538.
Abstract:
Using high pressure method polycrystalline powder samples of Mn1-xFexGe and Fe1-yCoyGe have been synthesized with x/y running from 0.0 to 1.0. The crystallite size for these compounds is in the order of 10 microns. SQUID magnetization and small angle neutron scattering (using SANS-1 at the MLZ, Garching) have revealed the helical magnetic ordering of the samples within the concentration range of x = [0.0 – 1.0] and y = [0.0 – 0.8]. The values of the helical wavevector k have been taken from the SANS pattern. As it could be seen in Fig.1 a) for Mn1-xFexGe the wavevector k remains roughly constant around 2 nm^-1 for x ≤ 0.4, while going down to a minimum for (|k| -> 0) at xc ≍ 0.75 and increases again to a value of 0.09 nm^-1 for pure FeGe. For Fe1-yCoyGe the k value smoothly decreases from 0.09 nm-1 for pure FeGe to its minimum at yc ≍ 0.6 and increase again for y = 0.8 to its maximum of 0.14 nm^-1 (Fig.1 b). For x/y -> xc/yc we observe a transformation of the helical magnetic structure to a ferromagnetic-like one at the critical concentrations. The change of the magnetic structure from helimagnetic to ferromagnetic-like goes along with a different sign of the magnetic chirality for x/y < xc/yc and x/y > xc/yc [1,2].
14
Del Zanna, Luca, Simone Landi, Lorenzo Serafini, Matteo Bugli, and Emanuele Papini. "A GPU-Accelerated Modern Fortran Version of the ECHO Code for Relativistic Magnetohydrodynamics." Fluids 9, no. 1 (January 6, 2024): 16. http://dx.doi.org/10.3390/fluids9010016.
Abstract:
The numerical study of relativistic magnetohydrodynamics (MHD) plays a crucial role in high-energy astrophysics but unfortunately is computationally demanding, given the complex physics involved (high Lorentz factor flows, extreme magnetization, and curved spacetimes near compact objects) and the large variety of spatial scales needed to resolve turbulent motions. A great benefit comes from the porting of existing codes running on standard processors to GPU-based platforms. However, this usually requires a drastic rewriting of the original code, the use of specific languages like CUDA, and a complex analysis of data management and optimization of parallel processes. Here, we describe the porting of the ECHO code for special and general relativistic MHD to accelerated devices, simply based on native Fortran language built-in constructs, especially do concurrent loops, few OpenACC directives, and straightforward data management provided by the Unified Memory option of NVIDIA compilers. Thanks to these very minor modifications to the original code, the new version of ECHO runs at least 16 times faster on GPU platforms as compared to CPU-based ones. The chosen benchmark is the 3D propagation of a relativistic MHD Alfvén wave, for which strong and weak scaling tests performed on the LEONARDO pre-exascale supercomputer at CINECA are provided (using up to 256 nodes corresponding to 1024 GPUs, and over 14 billion cells). Finally, an example of high-resolution relativistic MHD Alfvénic turbulence simulation is shown, demonstrating the potential for astrophysical plasmas of the new GPU-based version of ECHO.
15
Kłosowski, Zbigniew, and Sławomir Cieślik. "The Use of a Real-Time Simulator for Analysis of Power Grid Operation States with a Wind Turbine." Energies 14, no. 8 (April 20, 2021): 2327. http://dx.doi.org/10.3390/en14082327.
Abstract:
The main issue in this paper is the real-time simulator of a part of a power grid with a wind turbine. The simulator is constructed on the basis of a classic PC running under a classic operating system. The proposed solution is expected and desired by users who intend to manage power microgrids as separate (but not autonomous) areas of common national power systems. The main reason for the decreased interest in real-time simulators solutions built on the basis of PC is the simulation instability. The instability of the simulation is due to not keeping with accurate results when using small integration steps and loss of accuracy or loss of stability when using large integration steps. The second obstacle was due to the lack of a method for integrating differential equations, which gives accurate results with a large integration step. This is the scientific problem that is solved in this paper. A new solution is the use of a new method for integrating differential equations based on average voltage in the integration step (AVIS). This paper shows that the applied AVIS method, compared to other methods proposed in the literature (in the context of real-time simulators), allows to maintain simulation stability and accurate results with the use of large integration steps. A new (in the context of the application of the AVIS method) mathematical model of a power transformer is described in detail, taking into account the nonlinearity of the magnetization characteristics. This model, together with the new doubly-fed induction machine model (described in the authors’ previous article), was implemented in PC-based hardware. In this paper, we present the results of research on the operation states of such a developed real-time simulator over a long period (one week). In this way, the effectiveness of the operation of the real-time simulator proposed in the paper was proved.
16
VAN OERS, WILLEM T. H. "FROM HADRONIC PARITY VIOLATION TO PARITY-VIOLATING ELECTRON SCATTERING AND TESTS OF THE STANDARD MODEL." Modern Physics Letters A 23, no. 17n20 (June 28, 2008): 1266–77. http://dx.doi.org/10.1142/s0217732308027643.
Abstract:
Searches for parity violation in hadronic systems started soon after the evidence for parity violation in β-decay of 60 Co was presented by Madame Chien-Shiung Wu and in π and μ decay by Leon Lederman in 1957. The early searches for parity violation in hadronic systems did not reach the sensitivity required and only after technological advances in later years was parity violation unambiguously established. Within the meson-exchange description of the strong interaction, theory and experiment meet in a set of seven weak meson-nucleon coupling constants. Even today, after almost five decades, the determination of the seven weak meson-nucleon couplings is incomplete. Parity violation in nuclear systems is rather complex due to the intricacies of QCD. More straight forward in terms of interpretation are measurements of the proton-proton parity-violating analyzing power (normalized differences in scattering yields for positive and negative helicity incident beams), for which there exist three precision experiments (at 13.6, at 45, and 221 MeV). To-date, there are better possibilities for theoretical interpretation using effective field theory approaches. The situation with regard to the measurement of the parity-violating analyzing power or asymmetry in polarized electron scattering is quite different. Although the original measurements were intended to determine the electro-weak mixing angle, with the current knowledge of the electro-weak interaction and the great precision with which electro-weak radiative corrections can be calculated, the emphasis has been to study the structure of the nucleon, and in particular the strangeness content of the nucleon. A whole series of experiments (the SAMPLE experiment at MIT-Bates, the G0 experiment and HAPPEX experiments at Jefferson Laboratory (JLab), and the PVA4 experiment at MAMI) have indicated that the strange quark contributions to the charge and magnetization distributions of the nucleon are tiny. These measurements if extrapolated to zero degrees and zero momentum transfer have also provided a factor five improvement in the knowledge of the neutral weak couplings to the quarks. Choosing appropriate kinematics in parity-violating electron-proton scattering permits nucleon structure effects on the measured analyzing power to be precisely controlled. Consequently, a precise measurement of the ‘running’ of sin 2θw or the electro-weak mixing angle has become within reach. The [Formula: see text] experiment at Jefferson Laboratory is to measure this quantity to a precision of about 4%. This will either establish conformity with the Standard Model of quarks and leptons or point to New Physics as the Standard Model must be encompassed in a more general theory required, for instance, by a convergence of the three couplings (strong, electromagnetic, and weak) to a common value at the GUT scale. The upgrade of CEBAF at Jefferson Laboratory to 12 GeV, will allow a new measurement of sin 2θW in parity-violating electron-electron scattering with an improved precision to the current better measurement (the SLAC E158 experiment) of the ‘running’ of sin 2θW away from the Z0 pole. Preliminary design studies of such an experiment show that a precision comparable to the most precise individual measurements at the Z0 pole (to about ±0.00025) can be reached. The result of this experiment will be rather complementary to the [Formula: see text] experiment in terms of sensitivity to New Physics.
17
Tay, S. H., M. Stephenson, N. A. Allameen, S. Narayanan, B. Lee, and A. Mak. "POS0763 A MULTIMODAL MAGNETIC RESONANCE IMAGING STUDY OF COGNITIVE FUNCTION IN SYSTEMIC LUPUS ERYTHEMATOSUS: A MACHINE LEARNING APPROACH." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 668.1–668. http://dx.doi.org/10.1136/annrheumdis-2022-eular.3452.
Abstract:
BackgroundSystemic lupus erythematosus (SLE) is a multisystem autoimmune disorder that can affect the central nervous system. Cognitive dysfuncion is the most common neuropsyhiatric event in SLE patients, yet it is also one of the hardest to diagnose.ObjectivesTo investigate if multimodal imaging to assess anatomical magnetic resonance imaging (MRI) abnormalities in the brains of SLE patients can predict cognitive function.MethodsSubjects underwent voxel-based morphometry (VBM), magnetization transfer imaging (MTI), and dynamic contrast-enhanced (DCE) MRI. Automated Neuropsychological Assessment Metrics (ANAM) was used to assess cognitive function in this cross-sectional study and the primary measure was the total throughput score (TTS). TTS is the total of the throughput scores for each of the 8 ANAM subtests: (i) code substitution learning (CSL); (ii) code substitution immediate (CSI); (iii) code substitution delayed (CSD); (iv) spatial processing (SP); (v) matching to sample (MSP); (vi) running memory continuous performance test (CPT); (vii) mathematical processing (MTH) and (viii) memory search (MS). Olfactory assessment was done using the University of Pennsylvania Smell Identification Test. We used a machine learning-based model (i.e. GLMnet) to predict TTS. Subjects with active SLE disease or above 40 years old were excluded.ResultsThirty SLE patients [26 female, 32.0 (26.8-37.0) years] without clinically overt neuropsychiatric manifestations and 10 healthy controls (HCs) [9 females, 27.0 (23.0-31.5) years] were enrolled in this study. Both groups had comparable cognitive and olfactory functions. No significant differences were observed in VBM, MTR, olfactory blub and tract (OBT) volume in SLE patients compared to HCs. We observed increased blood-brain barrier (BBB) permeability parameters (Ktrans and PS) in several regions of SLE patients. DCE-MRI perfusion parameters such as perfusion (F) and vp but not permeability measures were associated with TTS. In particular, F right amygdala correlated with TTS in SLE patients (r = 0.636, FDR p < 0.05) (Table 1). Using GLMnet, we trained a multimodal MRI model comprising of VBM, MTR, DCE-MRI and OBT volume parameters to predict TTS in SLE patients (r = 0.998, p < 0.0005) (Figure 1).Figure 1.Machine learning-based models to predict cognitive function.Table 1.Correlation between ANAM tests with perfusion (F) in SLE patients, ranked in descending order of statistical significance for TTS.VariableTTSCSLCSICSDSPMSPCPTMTHMSF right amygdala0.636‡*0.520‡0.3370.437†0.559‡0.3230.633‡0.412†0.598‡F left entorhinal0.504‡0.422†0.3660.416†0.3050.1850.530‡0.1860.416†F left amygdale0.495‡0.400†0.1890.378†0.3300.2370.491‡0.376†0.449†F choroid0.469†0.384†0.2160.413†0.458†0.2020.456†0.3400.406†plexusF right rostal anterior cingulate0.453†0.3010.1180.2960.393†0.2140.547‡0.420†0.383†F right entorhinal0.448†0.368†0.2320.3120.376†0.1560.438†0.2710.407†F cerebellum white matter0.427†0.3580.2010.370†0.2730.0780.449†0.2900.297F left hippocampus0.427†0.3550.1340.390†0.3560.2030.511‡0.3360.332F brain stem0.407†0.2980.1380.2750.2940.1530.478‡0.3080.369†F right insula0.407†0.3080.0740.3000.3240.1760.437†0.3230.347F left parietal0.400†0.2630.0920.2540.2940.2240.487‡0.2740.332F ventricles0.396†0.3030.0830.3210.370†0.1920.477‡0.2860.361F right temporal0.395†0.2800.1130.2810.2880.1670.477‡0.3220.331F right hippocampus0.395†0.3070.0770.3250.3560.1900.486‡0.3570.339F right parietal0.376†0.2490.0820.2740.2830.1390.460†0.2550.311F right parahippocampal gyrus0.375†0.3530.1190.3020.3410.2410.3530.2080.273† p < 0.05, ‡ p < 0.01, *FDR p < 0.05ConclusionThese findings suggest that the BBB may be affected early in the course of cognitive dysfunction, even preceding detectable changes in other MRI sequences and machine learning algorithms can be used to predict TTS measures, even in asymptomatic SLE patients.ReferencesNil.Disclosure of InterestsSen Hee Tay: None declared, Mary Stephenson: None declared, Nur Azizah Allameen: None declared, Sriram Narayanan: None declared, Bernett Lee: None declared, Anselm Mak Speakers bureau: JnJ Apr 2019 and GSK Jan 2022, Grant/research support from: GSK - The Supported Studies Programme
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Zhu, Dantian, Wenhao Wu, Wenjun Yu, Guobin Hong, Yijie Fang, Shaolin Li, and Yajun Ma. "Ultrashort echo time magnetization transfer imaging of knee cartilage and meniscus after long-distance running." European Radiology, February 23, 2023. http://dx.doi.org/10.1007/s00330-023-09462-x.
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Fang, Yijie, Dantian Zhu, Wenhao Wu, Wenjun Yu, Shaolin Li, and Ya‐Jun Ma. "Assessment of Achilles Tendon Changes After Long‐Distance Running Using Ultrashort Echo Time Magnetization Transfer MR Imaging." Journal of Magnetic Resonance Imaging, January 21, 2022. http://dx.doi.org/10.1002/jmri.28072.
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"Electric Three-Wheeler: A Next-Gen Transport System for Developing Countries." International Journal of Recent Technology and Engineering 8, no. 6 (March 30, 2020): 966–70. http://dx.doi.org/10.35940/ijrte.f7430.038620.
Abstract:
Electric three-wheelers are now a day's becoming an emerging trend in the ecumenical market. Sundry manufacturers are coming into the market with different variants of electric three-wheelers. This paper aims to study these electrically powered three-wheelers comparing with conventional three-wheelers. As three-wheelers are the major source of road convey in developing countries and withal the more frugal one it is very consequential to study those. The conventional petrol engines, three-wheelers are engendering a plethora of pollution due to which electric three-wheelers are becoming a major source of magnetization in cities. Electric three-wheelers are comparatively very eco-cordial as they do not utilize any kind of fossil fuels. This paper aims to find a better alternative for sundry types of conventional three-wheeler running on the road. The exiting conveyances are to be superseded by the conveyance which can be operated utilizing a renewable source of energy, to minimize the unpropitious effects of conventional ones such as air pollution, low efficiency, high running cost, etc.
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Leveratto, A., A. Angrisani Armenio, A. Traverso, G. De Marzi, G. Celentano, and A. Malagoli. "Transport current and magnetization of Bi-2212 wires above liquid Helium temperature for cryogen-free applications." Scientific Reports 11, no. 1 (June 3, 2021). http://dx.doi.org/10.1038/s41598-021-91222-2.
Abstract:
AbstractSince the discovery of high temperature superconductors, a possible cryogen-free scenario has always been wished. Nowadays, liquid Helium is running out, and it is likely that the cooling by will be a large part of the costs of any superconducting system. Bi-2212 wires at temperature higher than 4.2 K still show a very high irreversibility field and thus a deep investigation of their properties in such a range of temperature is very useful in order to assess the applicability in high field cryogen-free magnets. Here electrical transport and magnetic properties characterization at variable temperature and magnetic field on our “GDG—processed” wires are reported together with a well-described original approach to calculate the irreversibility field Hirr. This study is devoted to provide reference data on the behaviour of the only isotropic wire for high field application with an eye to the performances at temperatures above 4.2 K.
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Wang, Qi, Roman Verba, Björn Heinz, Michael Schneider, Ondřej Wojewoda, Kristýna Davídková, Khrystyna Levchenko, et al. "Deeply nonlinear excitation of self-normalized short spin waves." Science Advances 9, no. 32 (August 11, 2023). http://dx.doi.org/10.1126/sciadv.adg4609.
Abstract:
Spin waves are ideal candidates for wave-based computing, but the construction of magnetic circuits is blocked by a lack of an efficient mechanism to excite long-running exchange spin waves with normalized amplitudes. Here, we solve the challenge by exploiting a deeply nonlinear phenomenon for forward volume spin waves in 200-nm-wide nanoscale waveguides and validate our concept using microfocused Brillouin light scattering spectroscopy. An unprecedented nonlinear frequency shift of more than 2 GHz is achieved, corresponding to a magnetization precession angle of 55° and enabling the excitation of spin waves with wavelengths down to 200 nm. The amplitude of the excited spin waves is constant and independent of the input microwave power due to the self-locking nonlinear shift, enabling robust adjustment of the spin-wave amplitudes in future on-chip magnonic integrated circuits.
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Takeuchi, Makoto, Motohiro Suzuki, Shintaro Kobayashi, Yoshinori Kotani, Tetsuya Nakamura, Nobuaki Kikuchi, Anton Bolyachkin, et al. "Real picture of magnetic domain dynamics along the magnetic hysteresis curve inside an advanced permanent magnet." NPG Asia Materials 14, no. 1 (August 19, 2022). http://dx.doi.org/10.1038/s41427-022-00417-0.
Abstract:
AbstractIn the long history of permanent magnet research for more than 100 years, three-dimensional magnetic microscopy has been eagerly awaited to elucidate the origin of the magnetic hysteresis of permanent magnets. In this study, we succeeded in observing the three-dimensional magnetic domain structure of an advanced high-coercivity Nd-Fe-B-based permanent magnet throughout the magnetic hysteresis curve using a recently developed hard X-ray magnetic tomography technique. Focused-ion-beam-based three-dimensional scanning electron microscopy was employed to study the relationship between the observed magnetic domains and the microstructure of the magnet for the same observing volume. Thermally demagnetized and coercivity states exhibit considerably different magnetic domain structures but show the same periodicity of 2.3 μm, indicating that the characteristic length of the magnetic domain is independent of the magnetization states. Further careful examination revealed some unexpected magnetic domain behaviors, such as running perpendicular to the magnetic easy axis and reversing back against the magnetic field. These findings demonstrate a wide variety of real magnetic domain behaviors along the magnetic hysteresis inside a permanent magnet.
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Kawanami, Tsuyoshi, and Shigeki Hirano. "Development and Fundamental Characteristics of a Prototype Magnetocaloric Heat Pump." MRS Proceedings 1310 (2011). http://dx.doi.org/10.1557/opl.2011.479.
Abstract:
ABSTRACTThe primary objective of this study is to discuss the optimum operating conditions of magnetocaloric heat pumps according to the fundamental heat transfer characteristics of an active magnetic regenerator (AMR) bed. The AMR cycle has four sequential processes: magnetization, heat exchange fluid flow, demagnetization, and heat exchange fluid blow. The fundamental heat transfer characteristics of each process of the AMR cycle is investigated minutely. Moreover, the cooling power and the overall system performance are evaluated when the system is running continuously.In addition to the aforementioned investigation, we have developed a prototype rotational magnetocaloric heat pump having a compact component arrangement and an uncomplicated control system. A performance evaluation has been conducted to obtain the optimum conditions for practical operation. The operation parameters such as the heat transfer fluid flow rate, rotational frequency, and initial temperature of the heat transfer fluid are examined, and the variations of the maximum temperature span between the inlet and outlet for the heat transfer fluid are discussed. As a result, the values of the optimum rotational frequency and flow rate are obtained to obtain the maximum temperature span between the inlet and outlet of the present magnetocaloric heat pump.
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Kozubski, Rafal, Miroslaw Kozlowski, Jan Wrobel, Tomasz Wejrzanowski, Krzysztof J. Kurzydlowski, Christine Goyhenex, Veronique Pierron-Bohnes, Marcus Rennhofer, and Savko Malinov. "Atomic Ordering in Nano-layered FePt: Multiscale Monte Carlo Simulation." MRS Proceedings 1177 (2009). http://dx.doi.org/10.1557/proc-1177-z09-03.
Abstract:
AbstractCombined nano- and mesoscale simulation of chemical ordering kinetics in nano-layered L10 AB binary system was performed. In the nano- (atomistic) scale Monte Carlo (MC) technique with vacancy mechanism of atomic migration was implemented with diverse system models. The mesoscale microstructure evolution was, in turn, modeled by means of MC procedure simulating antiphase boundary (APB) motion as controlled by APB energies evaluated within the nano-scale simulations. The study addressed FePt thin layers considered as a material for ultra-high density magnetic storage media and revealed metastability of the L10 c-variant superstructure with monoatomic planes parallel to the (001) free surface and off-plane easy magnetization. The layers, initially perfectly ordered in the L10 c-variant, showed homogenous disordering running in parallel with a spontaneous re-orientation of the monoatomic planes into a mosaic-microstructure composed of L10 a- and b-variant domains with (100)- and (010)-type monoatomic planes, respectively. The domains nucleated heterogeneously on the Fe free surface of the layer, grew discontinuously inwards its volume and finally relaxed generating an equilibrium microstructure of the system. Two �atomistic-scale� processes: (i) homogenous disordering and (ii) nucleation of the L10 a- and b-variant domains showed characteristic time scales. The same was observed for the meso-scale processes: (i) heterogeneous L10 variant domain growth and (ii) domain microstructure relaxation. The above phenomena modelled within the present study by means of multiscale MC simulations have recently been observed experimentally in epitaxially deposited thin films of FePt.
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Imperiale, Alexandre, Dominique Chapelle, and Philippe Moireau. "Sequential data assimilation for mechanical systems with complex image data: application to tagged-MRI in cardiac mechanics." Advanced Modeling and Simulation in Engineering Sciences 8, no. 1 (January 9, 2021). http://dx.doi.org/10.1186/s40323-020-00179-w.
Abstract:
AbstractTagged Magnetic Resonance images (tagged-MRI) are generally considered to be the gold standard of medical imaging in cardiology. By imaging spatially-modulated magnetizations of the deforming tissue, indeed, this modality enables an assessment of intra-myocardial deformations over the heart cycle. The objective of the present work is to incorporate the most valuable information contained in tagged-MRI in a data assimilation framework, in order to perform joint state-parameter estimation for a complete biomechanical model of the heart. This type of estimation is the second major step, after initial anatomical personalization, for obtaining a genuinely patient-specific model that integrates the individual characteristics of the patient, an essential prerequisite for benefitting from the model predictive capabilities. Here, we focus our attention on proposing adequate means of quantitatively comparing the cardiac model with various types of data that can be extracted from tagged-MRI after an initial image processing step, namely, 3D displacements fields, deforming tag planes or grids, or apparent 2D displacements. This quantitative comparison—called discrepancy measure—is then used to feed a sequential data assimilation procedure. In the state estimation stage of this procedure, we also propose a new algorithm based on the prediction–correction paradigm, which provides increased flexibility and effectiveness in the solution process. The complete estimation chain is eventually assessed with synthetic data, produced by running a realistic model simulation representing an infarcted heart characterized by increased stiffness and reduced contractility in a given region of the myocardium. From this simulation we extract the 3D displacements, tag planes and grids, and apparent 2D displacements, and we assess the estimation with each corresponding discrepancy measure. We demonstrate that—via regional estimation of the above parameters—the data assimilation procedure allows to quantitatively estimate the biophysical parameters with good accuracy, thus simultaneously providing the location of the infarct and characterizing its seriousness. This shows great potential for combining a biomechanical heart model with tagged-MRI in order to extract valuable new indices in clinical diagnosis.