Changes In Field Research Articles

The Halbach and alternating polarity linear magnets array are designed for microparticle separation, based on magnetophoresis

Abstract Particle separation using magnetophoresis requires an inhomogeneous magnetic field which affects the microparticle. The more changes in the magnetic field, the greater the magnetic force. The changes could exist in various ways. In this article, the change to produce a more intensive inhomogeneous magnetic field is generated by rotating the magnets to a specific degree. The analyses are done for three-state magnet arrays. For this purpose, a device is fabricated and the mentioned arrays are embedded in it. First, the results are simulated. The mathematical piecewise algorithm is used to validate the simulation. By examining the states in the fabricated device the experimental results are extracted. Overall, the results demonstrated that the Halbach and alternating polarity linear arrays (both 90, and 180 degrees) have better efficiency and throughput than the regular design array (without magnet rotating). The Halbach designs are illustrated with approximately the same results. However, in alternating polarity linear array, 180 degrees the particle capturing rate stood in a better place than the other design. 

Local Energy Minima and Density of Energy Barriers in Dense Clusters of Magnetic Nanoparticles

In this paper, we focus on the properties of local energy minima and energy barriers in immobilized dense clusters of magnetic nanoparticles. Understanding of these features is highly interesting both for the fundamental physics of disordered systems with long-range interparticle interaction and for numerous applications of modern ferrofluids consisting of such clusters. In particular, it is needed to predict the ac-susceptibility of these systems and their magnetization relaxation after a sudden change in the external field, because both processes occur via magnetization jumps over energy barriers that separate the energy minima. Due to the exponential increase in the corresponding jump time with barrier height (tsw∼exp(ΔE/kT)), direct Langevin dynamics simulations of this process are not feasible. For this reason, we have developed efficient numerical methods both for finding as many energy minima as possible and for the reliable evaluation of energy barriers between them. Our results for the distribution of overlaps between the local energy minima imply that there is no spin-glass state in such clusters even when they consist of particles with a small anisotropy. Further, we show that the distributions of energy barrier heights are qualitatively different for clusters of particles with small, intermediate, and large anisotropies, which has important consequences for the magnetization dynamics of these systems.

Path Planning Method for Wire-Based Additive Manufacturing Processes

The relevance of creating specialized computer programs that convert a virtual 3D model of an object into machine code (G-code) for controlling the process of 3D printing products from wire raw materials is substantiated. It is shown that for wire-based additive technologies, a fundamentally important requirement is to ensure the continuity of the surfacing trajectory within one section. A method for determining a continuous surfacing trajectory is proposed, the implementation of which requires two stages: performing a numerical analysis of a two-dimensional region with boundary conditions describing this section; and running a heuristic algorithm for the movement of the surfacing head, in which the direction of movement is selected based on the results of the analysis. The procedure for setting boundary conditions and an algorithm for numerically solving the boundary value problem of determining the field of the “height” function for each section are described. The principles of operation of the heuristic algorithm for selecting the direction of head movement based on the calculated height field and continuous determination of the proximity of adjacent layers and section boundaries are disclosed. An analysis of the algorithm operation is carried out using a section with holes as an example, and the potential of using numerical methods to calculate the change in the temperature field during the surfacing process is shown.

Exploring Ion Channel Magnetic Pharmacology: Are Magnetic Cues a Viable Alternative to Ion Channel Drugs?

We explore the potential of using magnetic cues as a novel approach to modulating ion channel expression, which could provide an alternative to traditional pharmacological interventions. Ion channels are crucial targets for pharmacological therapies, and ongoing research in this field continues to introduce new methods for treating various diseases. However, the efficacy of ion channel drugs is often compromised by issues such as target selectivity, leading to side effects, toxicity, and complex drug interactions. These challenges, along with problems like drug resistance and difficulties in crossing biological barriers, highlight the need for innovative strategies. In this context, the proposed use of magnetic cues to modulate ion channel expression may offer a promising solution to address these limitations, potentially improving the safety and effectiveness of treatments, particularly for long-term use. Key developments in this area are reviewed, the relationships between changes in ion channel expression and magnetic fields are summarized, knowledge gaps are identified, and central issues relevant to future research are discussed.

Director Response of Liquid Crystals in Spatially Varying Magnetic Fields with Antagonistic Anchoring Conditions.

In the presence of a magnetic field, a liquid crystal (LC) director can be distorted from a ground state set by a combination of LC elasticity and surface anchoring at any relevant interfaces. Uniform magnetic fields are often used to produce simple LC distortions on demand, but producing more spatially complex distortions is practically challenging. We develop a strategy for the spatially resolved control of the LC director by leveraging field patterns induced by ferromagnetic materials. Patterned magnetic fields are generated from high-permeability ferromagnetic microstructures embedded into nematic liquid crystals (NLCs) to manipulate the LC director's orientation. Each ferromagnetic microstructure produces a unique spatially varying magnetic field. In turn, tuning magnetic field strength in competition with NLC elasticity can pattern a range of spatially complex director configurations. Simulations relate the spatial variation induced in a magnetic field by a ferromagnetic geometry and the resultant director. Our predictive models can inform the inverse design of ferromagnetic microstructures to generate bespoke director patterns. We also link changes in the magnetic field to the migration of elastically driven periodic extinctions in birefringence near the edges of ferromagnetic structures.

Moisture dependent bending mechanical properties of Chinese fir

ABSTRACT Predicting the long-term deformation and failure of wood under varying environmental conditions is challenging due to the complex rheological behaviour of wood. In this study, the bending failure mechanism and moisture-dependent viscoelastic creep behaviours of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) were explored. The digital image correlation technique was used to monitor strain field changes during the bending process. The results revealed that wood in a dry state was more brittle than in a moist state. Strain field variations showed that the tensile load on the tension side primarily governs bending failure. There are distinct differences between tension and compression regions by fracture morphology analysis. The study further developed the time-moisture-stress superposition principle to integrate the effects of time, moisture, and stress on wood's creep behaviour in bending. These findings provide critical insights into how moisture affects wood’s mechanical behaviour, guiding more efficient design and manufacturing practices for long-term structural performance in the timber-construction industry.

A foreign object detection method based on a laminated coil for wireless power transfer

Foreign objects in magnetically coupled resonant wireless power transfer (MCR-WPT) systems cause eddy effects, reducing efficiency and raising the temperature. To address this, a high-frequency multilayer detection coil and composite topology circuit are designed to enhance sensitivity by dynamically adjusting component parameters. Verified through Maxwell simulation, the proposed method improves detection efficiency by 46% and eliminates blind spots compared to square coils. The detection range expands by 66% with a 3 × 3 reverse series-laminated coil, effectively decoupling sub-coils and broadening coverage. Experimental results show accurate detection of various foreign objects, such as iron and copper, by analyzing changes in magnetic fields and detection coil voltage. This approach enhances MCR-WPT system safety and efficiency, making it suitable for complex environments.

On elastic deformations of cylindrical bodies under the influence of the gravitational field

Background Elastic deformations of gravitating cylindrical bodies are relevant for state-of-the-art photonic experiments, as they affect the physical properties of materials under consideration, impacting wave propagation. This is of key importance for a recently planned experiment to explore the influence of the gravitational field on entangled photons propagating in waveguides. The purpose of this work is to determine these elastic deformations as functions of temperature, pressure, and of the gravitational field. We thus determine the deformations of the body due to changes of the gravitational field, and obtain stringent bounds on the control of temperature and pressure so that the effects of the associated elastic deformations on the photons propagating in a waveguide are smaller than the phase shifts associated with the change of the gravitational field. Methods We use the methods of linear elasticity, including thermoelasticity, to determine the stresses and strains of the medium. For this, the symmetry of the cylinder allows us to solve the problem by using Mitchell’s solutions of the equations satisfied by the Airy functions. The boundary conditions are implemented by an approximation of the Hertz contact method. Results We calculate the displacements, the stresses and strains for several classes of boundary conditions, and give explicit solutions for a number of physically motivated configurations. The influence of the resulting deformations on the planned GRAVITES experiment is determined. Conclusions The results are relevant for fiber interferometry experiments sensitive to the effects of the gravitational field on photon propagation. Our calculations give stringent bounds on the environmental variables, which need to be controlled in such experiments.

The Fine Structure of Coseismic Electromagnetic Response Based on Geomagnetic and Seismological Observations

This paper examines the response in geomagnetic field variations caused by the 2020–2023 earthquakes with magnitudes Mw ≥ 7.0 in the Aegean Sea and eastern Turkey. A detailed comparison of high-precision observations of the geomagnetic field and seismograms recorded at complex geophysical observatories within a radius of 3000 km from the epicenters was carried out. The joint analysis involves averaged 1-s data on the rate of change of the magnetic field and records from broadband seismic stations. Their characteristics are assessed in both time and frequency domains. The spectral characteristics of body and surface waves are separately compared with those of the geomagnetic signal. It is shown that the beginning of disturbance in the magnetic field at each observatory strictly coincides with the arrival of the P-wave and intensifies with the arrival of S-waves. The maximum geomagnetic disturbance is caused by surface waves. The amplitude of electromagnetic excitations is proportional to the amplitude of the parent seismic phases. Thus, the coseismic nature of the observed electromagnetic signal has been confirmed, suggesting its excitation in the Earth’s crust as seismic waves propagate.

The Air Transportation System as a Subsystem of Modern Communication Space: Analysis Based on Transfer Entropy Graphs

The processes of information exchange and the movement of material flows form a communication space that reflects the relationship of complex intersystem interactions in various spheres of our life within the framework of the concepts of information-theoretical theory. One of these concepts, reflecting the mutual influence between processes at a qualitative level, is the transfer of entropy. The direction and intensity of these flows reflect the main social and economic processes. As it is known, air transport is one of the most reliable and high-speed modes of transport, influencing the processes of socio-cultural interaction between different regions. This indirectly affects the development of industrial relations, the development of technology and intercultural exchange. New technologies in aviation improve the flight performance of airliners and reduce the costs of transporting passengers. The size and range of modern airliners are increasing, and ticket prices are being optimized. The processes of the liberalization of developing air transportation markets, the emergence of low-cost air carriers, open skies agreements, and the reduction in restrictions on the nomenclature of carriers and routes have led to the growth and diversity of air transport links. This article considers air transport as a complex system that takes into account the interconnectedness of the elements of the transportation system and the influence of some subsystems on others, which are not always obvious. The object of the study was the communication space formed on the basis of air transportation between regions of the world. To assess the dynamic properties of the world communication space, ICAO data for the period of 1970–2021 were used. The subject of the analysis was a time series reflecting the flows of passengers and cargo over the considered time horizon. The entropy transfer algorithm was used as an analysis tool. In the course of the research, the features of dynamic changes in the properties of the communication space were revealed. The analysis showed that the flows of entropy transfer between regions of the world change depending on political, economic, social, and technological factors. Examples of the application of the proposed approach are considered: an analysis of the cognitive model of the air transport flow structure, an analysis of the regional communication space, and an analysis of changes in the global communication field. The results of the analysis can be useful for assessing the development of the communication field of various regions, which will allow us to solve the problems of forming forecasts and effective scenarios for the development of transport flows at different hierarchical levels of economic management.

Estimating the Electric Fields Driving Lightning Dart Leader Development With BIMAP‐3D Observations

AbstractIn this paper, a numerical dart leader model has been implemented to understand the leader's development and the corresponding electric field changes observed by the 3D broadband mapping and polarization (BIMAP‐3D) system. The model assumes the extending leader channel is equipotential and has a linear charge distribution induced by an ambient electric field. The charge distribution induced by the ambient field can be used to model the electric field change at the ground. We then find the ambient electric field which best fits the field change measurements at the two BIMAP stations. The estimated ambient electric field decreases in the direction of dart leader propagation. Our observations and modeling results are consistent with our earlier hypothesis that dart leader speed is proportional to the electric field at the leader tip. The model also supports our earlier analysis that leader speed variations near branch junctions were due to previous charge deposits near the junctions. The modeled tip electric field is generally lower than the breakdown field unless the pre‐dart‐leader channel has a significant temperature of 3,000 K. This is consistent with the fact that dart leaders typically do not form new branches into the virgin air. Furthermore, the tip field is generally close to the negative streamer stability field at ambient temperatures, explaining the nature of the narrow and well‐defined channel structure. In addition to the charge distribution and the ambient and tip electric field, the development of the channel potential and current distribution are also presented.

Equations of magnetic field of transformer steel sheets

This study described a method for determining the magnetic field in transformer steel sheets for any magnetisation direction. In the proposed approach, limiting hysteresis loops for the rolling and transverse directions were used. These loops, which were determined separately in both directions, were modified depending on the direction of magnetisation. The assumed area of the magnetic field occurrence was divided into elementary segments, and the appropriate components of field strength and flux density were assigned to the edges and elementary segments of the grid dividing this area. The relationships between the flux density and field strength along both the rolling and transverse directions in the elementary segments were introduced into the equations of the magnetic field distribution, which were based on Maxwell’s equations in the integral form. These equations facilitated the determination of changes in the magnetic field, considering the magnetic hysteresis. The correctness of these equations was validated through comparisons of the results of numerical calculations with the analogous results of measurements performed using a laboratory package of transformer sheets.

Functional ultrasound and brain connectivity reveal central nervous system compromise in Trembler-J mice model of Charcot-Marie-Tooth disease

The Charcot-Marie-Tooth-1E (CMT1E) disease is typically described as a peripheral neuropathy in humans, causing decreased nerve conduction, spastic paralysis, and tremor. The Trembler-J (TrJ) mice serve as a high fidelity model of this disease. Here, we use functional ultrasound (fUS) and functional connectivity (FC) to analyze TrJ mice’s brain activity during sensory stimulation and resting state experiments against wild type (WT) mice - the healthy counterpart. fUS is an imaging technique that measures cerebral blood volume (CBV) temporal changes. We study these changes in the primary somatosensory cortex barrel field (S1BF) of both mice populations during periodic vibrissae stimulation, measuring the number of pixels that correlate to the stimulation (i.e., the size of the activation area), the average correlation of these pixels (i.e., the response strength), and the CBV’s rate of change for each stimulation (i.e., the hemodynamic response). Then, we construct a FC matrix for each genotype and experiment by correlating the CBV signals from the eight cortical regions defined by the Paxinos and Franklin atlas. Our results show that TrJ mice have significantly diminished neurovascular responses and altered brain connectivity with respect to WT mice, pointing to central nervous system effects that could shift our understanding of the CMT1E disease.

Unveiling the Structural, Electronic and Magnetic Properties of Gd4.5A0.5Si3O13 (A = K, Na, and Li) Oxides With Promising Potential for Low-Temperature Magnetic Cooling.

The growing demand for solid-state magnetic cooling, leveraging the magnetocaloric effect requires the discovery of high-performing magnetocaloric materials (MCMs). Herein, a family of Gd-containing MCMs is provided, specifically the Gd4.5A0.5Si3O13 (A = K, Na, and Li) oxides, which demonstratse exceptional low-temperature magnetocaloric performance. Through comprehensive experimental investigations and theoretical calculations on their structural, electronic, and magnetic properties, it is unequivocally confirmed that all of them crystallize in a hexagonal apatite-type structure (space group P63/m), exhibiting an antiferromagnetic semiconductor ground state with magnetic ordering temperatures below 1.8 K (typically ≈0.7 K for Gd4.5K0.5Si3O13). Furthermore, their remarkable maximum magnetic entropy change (-ΔSM max) values of 31.85 and 58.22 JkgK-1 for Gd4.5K0.5Si3O13; 25.31 and 55.01 JkgK-1 for Gd4.5Na0.5Si3O13; and 25.15 and 55.77 JkgK-1 for Gd4.5Li0.5Si3O13, under the magnetic field changes of 0-2 and 0-5 T, respectively, surpass those of prominent low-temperature MCMs, including the commercialized Gd3Ga5O12 (≈14.6 and 32.8 JkgK-1) paramagnetic salt. These findings in addition to their high environmental stability position these Gd4.5A0.5Si3O13 oxides as exceptionally promising for practical magnetic cooling applications.

Research and application of flying-wing aircraft bow wave modeling method based on convolutional neural network

With the development of aviation technology, aircraft voyage improvement has become an urgent problem to be addressed. Aerial refueling technology has been widely used as an important method for improving endurance. In probe-and-drogue refueling (PDR), the tanker's hose-drogue system is offset by the bow wave generated by the receiver's head. By probe-and-drogue refueling, we mean soft aerial refueling, which is a method that transfers fuel by connecting the drogue of tanker with the probe near the oil receiver's head to transfer fuel. The ability to accurately calculate flow field changes caused by the bow wave and the hose-drogue system offset position have become key factors for successful docking during PDR. However, existing bow wave models based on the potential flow method cannot accurately calculate the bow wave flow field of a flying-wing aircraft. Therefore, this paper proposes a variety of bow wave models based on a convolutional neural network (CNN), which aims to accurately solve the bow wave flow field of a flying-wing unmanned aerial vehicle in the process of autonomous aerial refueling. In addition, a method to calculate the hose-drogue system position based on the dynamics of a multi-body system is proposed, which calculates the final position of the hose-drogue system after docking from the coupled flow field of the tanker and receiver. Finally, by applying the bow wave model to the position calculation of the hose-drogue system, it was verified that the CNN model can be accurately applied to research related to aerial refueling.

The Distinct Spatial Patterns and Physical Mechanisms of Coastal Boundary Layer Jets over the Northern South China Sea

Abstract Two distinct spatial patterns of coastal boundary layer jets in the northern South China Sea (CBLJ-NSCS) in June 2015–22 are investigated using hourly output data from the Weather Research and Forecasting Model with a horizontal grid spacing of 9 km and ERA5 data. Spatial pattern 1 shows a high-incidence core on the east side of Hainan Island, while pattern 2 features dual high-incidence cores covering both the east side of Hainan Island and the waters south of Guangdong, with the latter being stronger and more extensive. Unique diurnal cycles have been observed in different high-incidence cores of CBLJ-NSCS: the western core, on the east side of Hainan Island, peaks at night and shows a secondary afternoon subpeak, while the eastern core, located south of Guangdong, reaches its maximum intensity at night with a morning subpeak. Inertial oscillations triggered by large-scale perturbation wind circulation and momentum propagation from upstream Indochina Peninsula CBLJs explain the nocturnal enhancement of both cores. The thermal effect exerted by Hainan Island largely contributes to the afternoon enhancement in the western core. The formation of the morning subpeak of the eastern core results from strong convergence and lifting in the northeast region of it. When upstream CBLJs along the Annamite Range intensify, more momentum is propagated to the eastern core instead of the western one due to wind field changes, which promotes the transition from spatial pattern 1 to pattern 2. Significance Statement Two spatial patterns of coastal boundary layer jets in the northern South China Sea have been identified. Spatial pattern 1 shows a high-incidence core on the east side of Hainan Island, while pattern 2 features dual high-incidence cores covering both the east side of Hainan Island and the waters south of Guangdong. The transition between these two spatial patterns is related to low-level westerly winds along the coast of the Annamite Range. This study has uncovered the novel spatial pattern of coastal boundary layer jets in the northern South China Sea and provides new insights into precipitation research in southern China, considering the substantial influence of these jets on coastal weather.

Study on Ice Temperature Fields and Borehole Closure Rates During Thermal Ice Drilling

Thermal ice drilling technology is extensively used in drilling operations such as temperature measurement holes and subglacial water environment investigations in Antarctica owing to its advantages of compactness, light weight, and ease of operation. However, thermal drilling disturbs the initial temperature of the surrounding ice, making it impossible to obtain the true ice temperature through a borehole within a short period. Meltwater refreezing also causes the borehole to shrink and close, posing a threat to drilling safety. Therefore, obtaining an accurate characterization of the temperature field around the hole and assessing the meltwater refreezing rate are crucial for determining the appropriate temperature measurement duration and optimizing drilling parameters. To address this issue, a temperature measurement platform for the ice surrounding the borehole was developed. Experimental investigations were conducted to analyze the temperature fields during thermal drilling using both small-diameter thermal heads and RECoverable Autonomous Sonde (RECAS) thermal heads. This study clarifies the temperature field changes in the surrounding ice during and after thermal drilling. It also elucidates the effects of parameters such as the ice temperature, thermal head heating power, and thermal head diameter on the temperature field around the hole and estimates the meltwater refreezing rate inside the borehole. The results indicated that the temperature of the surrounding ice peaked approximately 5–7 h after drilling and subsequently decreased and returned to the original temperature within 48 h. The thermal disturbance radius in the surrounding ice was approximately 1.1 to 1.7 times the borehole radius when the thermal head passed through. However, after the thermal head passed, the thermal disturbance radius continued to expand owing to the heat released from meltwater refreezing, reaching 9.7 to 12.5 times the borehole radius. The average meltwater refreezing rate, estimated from temperature measurement tests at −16 °C, was 3.6 mm/h.

Analysis of Industry 4.0 and the Building Inspection System in the Republic of Türkiye's Applications

Since the enactment of Law No. 4708 on Building Inspection, developments have taken place in the construction sector in Türkiye in terms of material production, their usage in construction sites, construction stages, project management, and implementation, which have led to the need for changes in the inspection field. In this study, the Building Inspection process was classified under seven headings within the scope of the Regulation. The fundamental problems in these headings were analyzed with research methods in the literature. Based on the information, which digital transformation technologies are included in the current practices and which ones are missing have been identified. Collaborations with which technology can solve existing problems have been interpreted, and solutions have been proposed to complete the shortcomings that may be experienced in the inspection field. It has been determined that Industry 4.0 Technologies should be adapted to every step of the inspection process for a healthy inspection system.

More accurate representation of interaction at the fluid–structure interface with an improved smoothed field gradient method

Flexible structures are wind-sensitive with a significant fluid–structure interaction (FSI). The FSI analysis, however, often has poor numerical stability and low convergence efficiency due to drastic changes of the physical fields induced by computation errors in local regions of the fluid–structure interface. This paper aims at addressing these problems with the proposal of a new method to smooth the gradient of the pressure field at the fluid–structure interface for an efficient convergence in the FSI analysis. The smoothed gradient theory is modified by introducing weight coefficients. The field of fluid pressure in each smoothing domain with large numerical fluctuations at the interface is then gradient smoothed with the proposed method and the modified field is obtained from the linear Taylor series expansion. The convergence of fluid and structure solvers for the proposed method is ensured within the commercial software FLUENT and ANSYS adopted. The proposed method is validated with experimental results from the literature. It is also numerically validated with a thin plate in viscous flow with different site categories and average wind velocities through comparison of results from conventional methods. The proposed method is found valid and accurate in the FSI analysis. It is relatively independent of a wide range of parameters with satisfactory robustness and notable improvement in the convergence of the FSI analysis.

Bias-induced polarization effect in Cd1-xZnxTe and Cd1-yMnyTe detectors

The study aims to compare the evolution of the electric field profiles in CdZnTe and CdMnTe detectors from the initial biasing activation until the steady state is reached (referred here as polarization effect). The crystals are grown by the same method, so the comparison emphasizes the difference between Zn- and Mn-based traps. The results demonstrate that the settling times in the CdZnTe and CdMnTe devices differ, but both are on the scale of hours. The effect of these, rather moderate variations on the charge collection efficiency for gamma photons should be limited. In addition, based on experimental results and TCAD calculations, it can be conjectured that a much stronger change in the electric field is induced by the bias polarization process in the front interface layer, which affects the charge collection only when carrier-generation occurring in and around the interface.