Current Moments Research Articles

Understanding magnetic fields, for NMR/MRI

The basic physics of magnetic fields is presented for a target audience of NMR workers. This group often does not have formal training in electromagnetism, but could benefit from an understanding of a selected subset of topics. The focus here is on a relatively non-mathematical view, intended to deliver an intuitive understanding of the topic. The covered topics start with the fields arising from simple idealized currents, including long straight wires, short flat coils, infinite current sheets, long solenoids, and magnetic dipole moments. The generation of field gradients and shim fields is discussed. All of these can be unified by considering the divergence and curl of the magnetic field. Magnetic materials are treated, both linear magnetizable materials (including the sample itself) and permanently magnetized materials; the approaches of equivalent currents and Ampere's theorem for magnetic circuits are presented.

Improving the Machine Learning Performance for Image Recognition Using a New Set of Mountain Fourier Moments

The orthogonal moments are giving relevant results of these last years within the framework of object detection, pattern recognition and image reconstruction. This article is based on orthogonal functions called "Orthogonal Mountain functions (OMFs)" and we introduce a new set of moments called the multichannel Mountain Fourier moments (MMFMs), their performance is in reconstruction, noise invariants, rotation, scale and translation for image color. To validate these proposed techniques, we made several experimental tests to analyse images. We compare the results obtained from invariant moments and other current orthogonal invariant moments; the experiments show the power of the proposed moments.

On the Rod Heating Problem by Sources on the Class of Zonal Controls Using the Current and Past State at Measurement Points

We study an optimal feedback control problem for the rod heating process by means of lumped sources. The control actions are the powers of the sources, the values of which are defined on the class of zonal controls. The values of the parameters of zonal control actions are determined by subsets of the state space, to which belong the values of the process state at the measurement points at the current and past time moments. The posed problem is reduced to a parametric optimal control problem on determining a finite-dimensional vector of values of the parameters of zonal control actions. We have obtained optimality conditions for the values of the parameters of zonal control actions. These conditions contain formulas for the gradient of the objective functional with respect to the optimizable parameters. They make it possible to solve the reduced problem numerically with the application of efficient first-order optimization methods.

ES-net: An Integration Model Based on Encoder–Decoder and Siamese Time Series Difference Network for Grade Monitoring of Zinc Tailings and Concentrate

In froth flotation, the tailings grade and concentrate grade are the two key performance indexes. At present, the monitoring models of these two key grades mostly use the froth image or video from a flotation cell. However, flotation cells are closely related and coupled seriously. It is difficult to use a froth image or video from a flotation cell to represent the concentrate or tailings grade. Therefore, an encoder-decoder and Siamese time series network (ES-net) is proposed. First, an encoder-decoder (ED) model is designed to predict target grade (i.e., the zinc tailings or concentrate grade) by the video feature sequence of the first rougher and the measured target grade sequence. Meanwhile, a Siamese time series and difference network (STS-D net) is constructed to predict the target grade by the video feature sequences of target flotation cell (i.e., the last scavenger or cleaner) at current and previous moments and the previously measured target grade. After that, a multi-task learning strategy is proposed to integrate the ED model and STS-D net. Experiments show that the proposed ES-net can effectively integrate multiple froth visual features from different flotation cells and obtain more accurate concentrate and tailings grades than the existing models.

Security of Food, Civilians and Combatants Under Human Rights Laws in Times of War

Objective: The International humanitarian law addresses the tension between safeguarding people and preserving the rights of soldiers within the intricate context of armed conflicts. The proposal sets up an in-depth examination of the complex processes that support the public and armed forces within this crucial legal framework in times of conflict. The core proposal, traces the evolution of armed conflicts and international humanitarian law from their earliest days to their present-day manifestations. The Conventions of Geneva and their supplementary protocols form the basis that allows the safety of civilians and ensure the foods in war zones. The significance of differentiating between those fighting and those living in a war zone, a core premise of international humanitarian law, is clarified. The proposed concept of proportionality is investigated, bringing down the complex math that goes into balancing military requirements with the desire to prevent civilian injury. The theoretical framework offers instances taken from earlier times and current moments that illustrate the quiet interplay of these ideas. The implementation of international humanitarian law poses major challenges in an atmosphere marked by non-governmental organizations, unconventional strategies, and technological advances. The work analyzes these contemporary challenges and highlights the fuzzy boundary that divides combatants and people in this time of increased uncertainty. Migration, lack of food, mortality, and lifelong communal traumas often rush to the head when citizen safety is violated.
 
 Method: The security of Civilians based on Human Rights (SC-HR) of war emphasizes the core principles of humanitarian law even amid conflict, emphasizing the crucial function for international organizations and humanitarian actors in alleviating humanitarian pain.
 
 Result: The proposal provides an expression of the fundamental rights of combatants by explaining the safety measures and food provided to these individuals by international humanitarian law.
 
 Conclusion: This inquiry exposes the complex balancing act of contemporary combat as it tries to reconcile these liberties with the demands of the armed forces. The proposed method focuses on the processes employed for upholding international humanitarian law.

Methodology for Calculating Course Errors when Aiming an Aircraft at a Maneuvering Air Target

The article presents theoretical calculations that explain the origin of errors in the course of an aircraft in an automated control system when pointing at a maneuvering air target. The peculiarity of pointing at a maneuvering target is related to the execution of turns, which are characterized by overloads. The curvature of the trajectory in such areas is usually approximated by a circle of a certain radius, depending on the value of the overload and flight speed to intercept. In the automated control system, the current course of the aircraft is determined as the direction of movement by two marks corresponding to the current and previous moments of information update time. For a target moving in a straight line, this approach is valid. However, in a turn where the guidance path is a curved line, the true heading will correspond to the tangent at the turn point. The difference in these approaches determines the error of the course calculation. This article provides a formulaic calculation of turn radii for flight speeds to intercept an air target and overloads, as well as the calculation of true and current courses. The peculiarity of the methodology is a strict formalized mathematical description. The article presents the dependences of heading errors from the aircraft’s intercept flight speed and overloads using the example of the Su-27 multifunctional fighter.

Different Types of Corona Discharges Associated With High‐Altitude Positive Narrow Bipolar Events Nearby Cloud Top

AbstractSingle‐ and multi‐pulse blue corona discharges are frequently observed in thunderstorm clouds. Although we know they often correlate with Narrow Bipolar Events (NBEs) in Very Low Frequency/Low Frequency radio signals, their physics is not well understood. Here, we report a detailed analysis of different types of blue corona discharges observed by the Atmosphere‐Space Interactions Monitor during an overpass of a thundercloud cell nearby Malaysia. Both single‐ and multi‐pulse blue corona discharges were associated with positive NBEs at the top of the cloud, reaching about 18 km altitude. We find that the primary pulses of multi‐pulse discharges have weaker current moments than the single‐pulse discharges, suggesting that the multi‐pulse discharges either have shorter vertical channels or have weaker currents than the single‐pulse discharges. The subsequent pulse trains of the multi‐pulse discharges delayed some milliseconds are likely from horizontally oriented electrical discharges, but some NBEs, correlated with both single‐and multi‐pulse discharges, include small‐amplitude oscillations within a few microseconds inside their waveforms, which are unresolved in the optical observation and yet to be understood. Furthermore, by jointly analyzing the optical and radio observations, we estimate the photon free mean path at the cloud top to be ∼6 m.

Detailed magnetoelectric analysis of a nerve impulse propagation along the brachial plexus

ObjectiveTo visualize impulse conduction along the brachial plexus through simultaneous electromagnetic measurements. MethodsNeuromagnetic fields following median nerve stimulation were recorded above the clavicle with a superconducting quantum interference device biomagnetometer system in 7 healthy volunteers. Compound nerve action potentials (CNAPs) were obtained from 12 locations. Pseudocolor maps of equivalent currents reconstructed from magnetic fields and isopotential contour maps were superimposed onto X-ray images. Surface potentials and current waveforms at virtual electrodes along the brachial plexus were compared. ResultsIn magnetic field analysis, the leading axonal current followed by a trailing backward current traveled rostrally along the brachial plexus. The spatial extent of the longitudinal intra-axonal currents corresponded to the extent of the positive–negative-positive potential field reflecting transmembrane volume currents. The peaks and troughs of the intra-axonal biphasic current waveforms coincided with the zero-crossings of triphasic CNAP waveforms. The amplitudes of CNAPs and current moments were linearly correlated. ConclusionsReconstructed neural activity in magnetic field analysis visualizes not only intra-axonal currents, but also transmembrane volume currents, which are in good agreement with the surface potential field. SignificanceMagnetoneurography is a novel non-invasive functional imaging modality for the brachial plexus whose performance can surpass that of electric potential measurement.

Rod temperature regulation using current and time-delayed feedback

The synthesis problem of control of objects with distributed parameters with feedback is investigated on the example of the process of heating a rod in a furnace. To generate the values of control actions, we propose to use their linear de- pendence on the values of the state at the measurement points, both at the current and previous moments of time. The unknown coefficients involved in this dependence of control on the measured state values are feedback parameters. They are deter- mined by minimizing the objective functional using numerical methods of first-order optimization. Formulas for the gradient of the objective functional with respect to the feedback parameters are obtained. The results of numerical experiments are presented.

Control of spin current and antiferromagnetic moments via topological surface state

Control of spin current and antiferromagnetic moments via topological surface state

Longing as Method: A Rant on Yearnings for Our World, Academia, and Utopian Futurities Beyond Liberalism(s)

Together we found ourselves discussing current moments of racialized formations, pandemic practices, academic policing, equity projects (equity, diversity, and inclusion [EDI] initiatives), and our use, among it all. Like Adrienne Maree Brown, we were “formulating [our] critique of the ways that social justice movements have felt, and where [our] longing for something else was strongest” (2017, p. 44). This article, therefore, used longing as method for unearthing those embodied yearnings that arose within us against discontents, empty promises, and institutional lackings toward useful questionings, hope-full cravings, and progressive desires for more just futurities for our world(s), academies, and utopias beyond. In conversation with various radical thinkactors, this rant traces our longings as method for considering something otherwise. We begin with, and continually revisit, a question triggered by our readings of Ahmed: what is our use?

Manipulation of spin Hall magnetoresistance and unidirectional spin Hall magnetoresistance in Ta/Pt/CoFeB multilayers

The interaction between spin current and magnetic moments in heavy metal (HM)/ferromagnetic (FM) structure results in the well-known spin orbit torque and the concomitant magnetoresistance effect: spin Hall magnetoresistance (SMR) and the unidirectional SMR (USMR). In this work, we simultaneously investigated the SMR and USMR in Ta/Pt/CoFeB/MgO multilayers with different Pt thickness (tPt) by the harmonic measurements. It is observed that at tPt≈0.9nm, the SMR is close to zero and the polarity of USMR reverses, which originate from the competition of the spin current from Ta and Pt layers. Under the theoretical framework of the spin diffusion equation, we derived the theoretical expressions of SMR and USMR in the tri-layer magnetic heterostructures. We found that the tPt dependences of the SMR and USMR can be well fitted by the expressions, from which the spin transport parameters of Pt were extracted. Our work provides a fundamental insight into spin transport in the system with two heavy-metal layers, and a possible way to control SMR and USMR of HM/FM systems.

Siamese Time Series and Difference Networks for Performance Monitoring in the Froth Flotation Process

Accurate and in-time performance monitoring plays a great role in industrial processes. However, since the labeled performances are usually measured by some special devices with a relatively long-time interval, the current deep neural networks for the performance monitoring always treat them only as an output. But actually, in the industrial process like froth flotation, labeled performance at the previous moment could also offer valuable information for performance monitoring at the current moment, especially under unstable working conditions. Therefore, we propose a Siamese time series and difference network (STS-D net), which integrates input features at different time steps and labeled performance at the previous moment effectively. In this article, the proposed STS-D net includes two sub-networks. One is the Siamese time series network, which aims to extract effective and uniform feature representations for the input time series at the current and previous moments; the other is the difference network, which integrates the feature representations of the two input time series with labeled performance at the previous moment to predict the performance at the current moment in an incremental way. Effectiveness of the proposed STS-D net is validated in a real-world froth flotation process.

Linear momentum flux from inspiralling compact binaries in quasielliptical orbits at 2.5 post-Newtonian order

Emission of anisotropic gravitational radiation from compact binary system leads to a flux of linear momentum. This results in the recoil of the system. We investigate the rate of loss of Linear momentum flux in the far zone of the source using various mass type and current type multipole moments for inspiralling compact binary mergers in quasi-elliptical orbits at 2.5 Post Newtonian order. We compute the linear momentum flux accurate up to $\mathcal{O}(e_t)$ in harmonic coordinate. A 2.5 Post Newtonian Quasi-Keplarian representation of the parametric solution to the Post Newtonian equation of motion for the compact binary system has been adopted here. We also provide a closed-form expression for the accumulated linear momentum from the remote past through the binary evolution.

Review: The Japanese Cinema Book, edited by Hideaki Fujiki and Alastair Phillips; Routledge Handbook of Japanese Cinema, edited by Joanne Bernardi and Shota T. Ogawa; A Companion to Japanese Cinema, edited by David Desser

Review: <i>The Japanese Cinema Book</i>, edited by Hideaki Fujiki and Alastair Phillips; <i>Routledge Handbook of Japanese Cinema</i>, edited by Joanne Bernardi and Shota T. Ogawa; <i>A Companion to Japanese Cinema</i>, edited by David Desser

Scientific Journal of Sport and Performance: A new trend of physical exercise and sports performance in 2022

In these current moments of global uncertainty due to the pandemic, the world of Physical Activity and Sport Sciences is facing the reality of a new positioning in the basic priorities of people, since it is incorporated into the list of attributes most important in our society.

Remote Measurement of the Lightning Impulse Charge Moment Change Using the Fast Electric Field Antenna

The impulse charge moment change (iCMC) is an important electrical property of cloud-to-ground (CG) lightning. In this paper, a new method of measuring the iCMC at distances of several hundred kilometers is proposed. The method is based on the vertical electric field below 1 kHz measured by the widely used fast electric field antenna with low frequency/very low frequency (LF/VLF) band. The impulse response of Earth-ionosphere waveguide (EIWG) is modeled using a finite difference time domain (FDTD) method considering an anisotropic ionosphere. By comparing the observed waveform with the simulated impulse response, the lightning discharge is classified into the impulsive discharge and the non-impulsive discharge. For the impulsive discharge, its iCMC is obtained directly by comparing the measured ELF waveform to the modeled impulse response at the same distance. For the non-impulsive discharge, its current moment waveform is assumed to be a sum of two Heidler’s functions, and the genetic algorithm is used to search the unknown parameters in the functions. The good agreement between the measured ELF waveform and the simulated waveform implies that the extracted current moments are reasonable. This method can be used to continuously monitor the lightning iCMC in a given time and space.

Post-Newtonian waveforms from spinning scattering amplitudes

We derive the classical gravitational radiation from an aligned spin binary black hole on closed orbits, using a dictionary built from the 5-point QFT scattering amplitude of two massive particles exchanging and emitting a graviton. We show explicitly the agreement of the transverse-traceless components of the radiative linear metric perturbations — and the corresponding gravitational wave energy flux — at future null infinity, derived from the scattering amplitude and those derived utilizing an effective worldline action in conjunction with multipolar post-Minkowskian matching. At the tree-level, this result holds at leading orders in the black holes’ velocities and up to quadratic order in their spins. At sub-leading order in black holes’ velocities, we demonstrate a matching of the radiation field for quasi-circular orbits in the no-spin limit. At the level of the radiation field, and to leading order in the velocities, there exists a one-to-one correspondence between the binary black hole mass and current quadrupole moments, and the scalar and linear-in-spin scattering amplitudes, respectively. Therefore, we show explicitly that waveforms, needed to detect gravitational waves from inspiraling binary black holes, can be derived consistently, to the orders considered, from the classical limit of quantum scattering amplitudes.

Тәуелсіз Қазақстан кезеңіндегі Жошы Ұлысы тарихының зерттелуі

The article presents a historiographical review of works related to the history of the Jochi Ulus, one of the most pressing issues in the history of independent Kazakhstan. In particular, as the main problem, attention is paid to conceptual changes and new views in the works of domestic researchers on the topic after the collapse of the Soviet state. Analyzing scientific works, the author divides the national historiography of the period of independence into two stages, reflecting the dynamics of changing opinions and the evolution of the emergence of new data and thoughts. This topic was discussed in academic circles, and then subjected to a comprehensive examination, up to an increase in state degrees. It is noteworthy that historians connect the current moments in the history of the Jochi Ulus with the Kazakh Khanate that developed in the following centuries. The main sources of the article are publications and articles published during this period. The author is looking for a unique paradigm in the study of the history of the Jochi Ulus in the works of domestic researchers over the past thirty years and seeks to determine the course and degree of studying the modern topic. The paper presents a selection of new theoretical ideas concerning the history of the Jochi Ulus, using the analysis of the works of domestic researchers. In particular, it will reflect the moments of the history of the modern Middle Ages that require significant changes in the form of research, including the formation of a new concept of «Ulus Jochi». The author concludes that the new concept « Kazakhstan is the heir of the Golden Horde (Ulus of Jochi)» was supported by Kazakh scientists and gave a powerful impetus to the promotion of the continuity of states to a certain extent.

Pandemics, Delays, and Pure Data: on ‘afterlives’ (2020), for Flute and Live Electronics and Visuals

The essay addresses creative and technical aspects of the piece ‘afterlives’ (2020), for flute and live electronics and visuals. Composed and premiered in the context of the COVID-19 pandemic, the composition employs audiovisual processes based on different audiovisual techniques: phase-vocoders, buffer-based granulations, Ambisonics spatialization, and variable delay of video streams. The resulting sounds and images allude to typical situations of social interaction via video conferencing applications. ‘Afterlives’ relies on an interplay between current, almost-current, and past moments of the audiovisual streams, which dephase the performer’s images and sounds. I have avoided, in text, delving deeper into the Pure Data abstractions and or into the musical analysis of my composition. The main purpose of the text is rather to present compositional/technical elements of ‘afterlives’ and discuss how they enable new experiences of time.