Current Shape Research Articles

Plasma dynamics of individual HiPIMS pulses: imaging study using high-frame-rate camera

Abstract A high-frame-rate camera with microsecond-level time resolution was used to make systematic investigations of plasma self-organization and spoke dynamics during individual HiPIMS pulses. The plasma was imaged for a range of argon pressures (0.25-2 Pa) and peak discharge currents (10-400 A) using an Al target. The experiments revealed that plasma evolves through three characteristic stages as the discharge current increases. In stage I, which is present from the current onset and up to ~25 A, spokes are azimuthally long and rotate in the -E×B direction. The spoke behavior is similar to the one observed in DCMS discharges. The number of spokes depends on pressure and the current growth rate. At the lowest pressure (0.25 Pa) a single spoke is present in discharge, while at higher pressures (1-2 Pa) two spokes are most often observed. The spoke velocity depends on the number of spokes, current growth rate and pressure. A single spoke rotates with velocities in the 4-15 km/s range, while two spokes rotate in the 1-9 km/s range depending on the pressure and growth rate. Following stage I, the plasma undergoes a complex reorganization that is characterized by aperiodic spoke patterns and irregular dynamics. In stage II spokes are less localized, they merge, split and propagate either in the retrograde or prograde direction. After chaotic plasma reorganization, more ordered spoke patterns begin to form. Spokes in stage III are azimuthally shorter, typically exhibit a triangular shape and rotate in the E×B direction. In general, the spoke dynamics is less complicated and is only influenced by the pressure. Spokes rotate faster at higher pressures than at lower ones; velocities range from 9 km/s at 0.25 Pa to 6 km/s at 2 Pa. The spoke velocity in stage III is largely unaffected by the discharge current or number of spokes. Stage III can be further divided into sub-stages, which are characterized by different current growth rates, spoke sizes and shapes. In general, the spoke evolution is highly reproducible for pulses with similar discharge current waveforms.

Seaweed diversification driven by Taiwan’s emergence and the Kuroshio Current: insights from the cryptic diversity and phylogeography of Dichotomaria (Galaxauraceae, Rhodophyta)

Ocean currents play a role in both facilitating and impeding connectivity of marine organisms’ populations, serving as key drivers and potential barriers. The emergence of Taiwan around five million years ago (Mya) impacted the Kuroshio Current which later shaped the distribution of marine organisms. In this study, we examined how the Kuroshio Current influenced the distribution and population divergence of the marine red alga Dichotomaria elegans (Galaxauraceae, Nemaliales). Through phylogenetic analysis, species delimitation, and morphological comparison of Taiwanese species, we determined its phylogenetic position relative to other species within the D. marginata complex of the genus Dichotomaria. We uncovered the hidden cryptic diversity within the D. marginata complex in Taiwan and proposed the new combinations D. elegans and D. latifolia based on Galaxaura elegans and G. latifolia. Genetic analysis based on three loci (mitochondrial cox2-3 and cox1, and plastid rbcL) from 32 locations across the Philippines, Taiwan, and Japan revealed three allopatric lineages within D. elegans. The first lineage is restricted to the northern Philippines and southern Taiwan, while the second has a broader latitudinal range along the Kuroshio Current. The third lineage is found in southeast Luzon, Philippines, close to the bifurcation of the North Equatorial Current, near the start of the Kuroshio Current. The divergence of the first two lineages during the mid-Pliocene (~3.7 Mya) coincided with the emergence of Taiwan, with the current dynamics accentuating their separation. The Kuroshio Current exhibited a dual impact on the biogeography of D. elegans: promoting the dispersal of the second lineage towards higher latitudes and preventing the first lineage from moving northward. Principal component analysis showed that habitat conditions and morphologies differed between the two D. elegans lineages. This study provides insights into the cryptic diversity of Dichotomaria in Taiwan, as well as the genetic divergence, biogeographical patterns, and ecological associations of D. elegans, highlighting the interplay of island formation and currents shaping the diversification of seaweeds in the Northwest Pacific Ocean.

Understanding the Nonlinear Response of SiPMs.

A systematic study of the nonlinear response of Silicon Photomultipliers (SiPMs) was conducted through Monte Carlo (MC) simulations. The MC code was validated against experimental data for two different SiPMs. Nonlinearity mainly depends on the balance between the photon rate and the pixel recovery time. Additionally, nonlinearity has been found to depend on the light pulse shape, the correlated noise, the overvoltage dependence of the photon detection efficiency, and the impedance of the readout circuit. Correlated noise has been shown to have a minor impact on nonlinearity, but it can significantly affect the shape of the SiPM output current. Considering these dependencies and a previous statistical analysis of the nonlinear response of SiPMs, two phenomenological fitting models were proposed for exponential-like and finite light pulses, explaining the roles of their various terms and parameters. These models provide an accurate description of the nonlinear responses of SiPMs at the level of a few percentages for a wide range of situations.

Observing the dynamics of urban growth of Al-Baha City using GIS (2006–2021)

This study observes and records land cover changes in Al-Baha to track urban growth. The study develops a schematic vision of urban mass's current and future shape and distribution and its growth to achieve sustainable urban development, reduce service and social differences between city areas, and integrate urban and rural areas. The study uses inductive methods to monitor urban developments, population growth, and land use through Al-Baha's structural schemes by extracting digital data from satellite imagery to survey historical land cover changes. The mapping software ArcGIS v10.8 processed these digital data and the final map compositions. Through this urban mass study, the research predicted city growth and development. Capabilities and functions must shape urban and rural-urban communities. The development must also consider the National Urban Development Strategy, the relative importance of rural-urban communities, and their expected functional role in influencing the development of small rural communities adjacent to them to reduce migration from rural areas near the city. The study highlighted changes in city land coverage. Al-Baha expanded from 1982 to 1995. Al-Baha's transformation from village to city accelerated, increasing its area from 31 km2 to 44 km2. Many villages beyond 40 were included in the decisions. From 2006–2021, the city's area grew 221%. It increased from 60 km2 to 133 km2 in an urban area, indicating false urban growth. The study stressed the importance of geographic information systems (GIS) and remote sensing (RS). The study recommends urban development in suitable areas because agricultural development is not feasible, especially in the northeast. Land use changes should be prevented by planning regulations because these agricultural areas are essential. Helping urban development move away from agricultural areas, especially on the eastern axis, is crucial. Create new urban centers along Al-Baha's western cliff to attract residents and relieve pressure. Limited linear expansion, especially in the northeast, and more expansive urbanization are also significant. Maps should also show when the Al-Baha region's expansionary scope changed and the urban boundaries that had to be reached by a specific time while development plans were efficiently monitored.

Surface structure evolution and measurement analysis of Ti6Al4V titanium alloy by electric arc electrochemical machining

In this study, a theoretical model about the conversion mechanism of material removal by electric arc electrochemical machining (EAECM) was derived. The limiting conversion rate of ECM-EAECM was measured on this basis. The current waveform, surface integrity, shape accuracy and process indexes during machining were measured and evaluated. The results showed that when the limiting conversion rate of ECM was exceeded, the material removal consisted of alternating effects of electric arc machining (EAM) and ECM. The proportion of EAM increased and the surface structure evolved into discharge defects, verifying the correctness of the theory. In addition, parametric crossover experiments were performed to clarify the degree of parametric response to EAECM modulation. Finally, the optimal combination of parameters resulted in a material removal rate of up to 5452 mm3/min, a relative electrode wear rate of 1.39 %, and a surface roughness of only 4.62 μm.

Revolutionising EFL pedagogy: Innovative strategies for integrating GAI (ChatGPT) into language teaching

The recent emergence of cutting-edge Generative Artificial Intelligence (GAI) technology has gained significant attention across diverse domains, and education has not been shielded from its influence. However, the integration of GAI in education remains nascent, with scant attention paid to offering strategic guidance for its specific application in English language teaching. Employing ChatGPT as an example, this article aims to provide English teachers with innovative strategies for incorporating GAI into their daily teaching practices, encompassing class preparation, in-class and after-class instruction and its utilisation as an academic research assistance tool. Furthermore, it highlights the potential challenges and risks associated with adopting GAI in language education, urging teachers to exert timely intervention and guidance when incorporating this technology. Ultimately, the article strives to revolutionise current English teaching pedagogy and shape the future of educational practices.

Adaptive patch grid strategy for parallel protein folding using atomic burials with NAMD

The definition of protein structures is an important research topic in molecular biology currently, since there is a direct relationship between the function of the protein in the organism and the 3D geometric configuration it adopts. The transformations that occur in the protein structure from the 1D configuration to the 3D form are called protein folding. Ab initio protein folding methods use physical forces to model the interactions among the atoms that compose the protein. In order to accelerate those methods, parallel tools such as NAMD were proposed. In this paper, we propose two contributions for parallel protein folding simulations: (a) adaptive patch grid (APG) and (b) the addition of atomic burials (AB) to the traditional forces used in the simulation. With APG, we are able to adapt the simulation box (patch grid) to the current shape of the protein during the folding process. AB forces relate the 3D protein structure to its geometric center and are adequate for modeling globular proteins. Thus, adding AB to the forces used in parallel protein folding potentially increases the quality of the result for this class of proteins. APG and AB were implemented in NAMD and tested in supercomputer environments. Our results show that, with APG, we are able to reduce the execution time of the folding simulation of protein 4LNZ (5,714 atoms, 15 million time steps) from 12 hours and 36 minutes to 11 hours and 8 minutes, using 16 nodes (256 CPU cores). We also show that our APG+AB strategy was successfully used in a realistic protein folding simulation (1.7 billion time steps).

Addressing the Shortage of Sports Officials

This article discusses the nationwide shortage of sports officials, best practices and solutions, and how current physical educators, coaches and SHAPE America members in general can help address the shortage and educate youths on the value of sportsmanship.

Renewable Energy Sources, Sustainability and Environmental Protection: A Review

Energy plays a vital role in any country`s economic development. As such proper and adequate supply of energy is fundamental for environmental, social, and economic development. Renewable energy has ticked all the boxes to be considered the best energy source because it is environmentally friendly. Renewable energy is considered a clean source of energy because it generates limited secondary pollutants from burning fossil fuels. Conventional fossil fuels, which are a limited resource, provide a significant share of the main energy demand, but renewable energy development represents a significant step towards social, economic, and environmental growth. Due to the ever-increase demand for energy as a result of over growing human population which cannot be modified by the current shape of the earth due to how fast the world is becoming a virtual community. The requirement for energy and related services to meet human growth can be seen in welfare, social, health, and economic development. The need for renewable energy sources to combat climate change and protect our environment is a great strategy that needs to be sustainable to satisfy future generations’ energy needs. This paper describes the development opportunities related to renewable energy sources and their sustainability, environmental safety, social, and energy security, economic strength, and expanding access to affordable, safe, and cheaper energy. This helps provide a foundation for addressing the demand for sustainable development. 

Numerical study of transient supercooling performance and thermal stress analysis of segmented annular thermoelectric cooler

A multiphysics-coupled numerical simulation of a segmental annular thermoelectric cooler (SATEC) was performed using a three-dimensional finite element method. A coupling model of the temperature, stress, and electric fields was established based on the three-dimensional transient states. Moreover, the effects of different pulse width (τ), pulse current amplitude (Pa), pulse current shape parameter (m), heat transfer coefficient (h), angle (θ), and length (H) of the thermoelectric leg on the SATEC transient properties and von Mises stress were studied. The results show that τ and Pa are the key influencing factors of SATEC. The larger the h, the more optimized the heat transfer effect of the SATEC hot end. However, when h increased to a certain value, the changes in the transient performance were insignificant. The optimal pulse can be achieved when the input pulse current Iop = 6.47 A and pulse width τ = 20 s. When the length of the thermoelectric leg H4 was 3 mm and the thermoelectric leg angle θ2 was 7°, the performance of SATEC was optimal, with Tc,min being 249.57 K, Tc,max being 279.50 K, thold being 5.5 s, and the maximum von Mises stress being 37.48 MPa. The results show that different supercooling indices and von Mises stresses could be obtained for different pulse current shapes. Geometric optimization of SATEC can improve the cooling performance and reduce the von Mises stress, thereby providing a theoretical reference for practical engineering applications and thermoelectric cooling research.

The depositional characteristics of turbidity current in Manila Trench: sediment provenance, geochemical elements and organic carbon burial

Turbidity currents play a significant role in sediment transport in deep ocean, profoundly impacting sedimentation in the abyssal sea. This study focused on a 375 cm long sediment core collected from the Manila Trench, revealing a distinctive 15 cm turbidite layer characterized by coarse sediment, an upward fining pattern, and a basal erosion surface. Analysis of rare earth elements and Nd isotope indicates that this turbidite layer originated from Taiwan Island. Initiated in the estuarine shelf region of southwestern Taiwan Island, the turbidity current transported substantial biogenic debris and marine fresh organic carbon into the Manila Trench. Consequently, the turbidite layer exhibited an elevated CaO content and more positive δ13C values. Despite lower TOC content in the turbidite layer due to coarse particle size, the mixture of marine fresh organic matter significantly lowered the carbon age of this layer compared to the strata both below and above it. The rapid sedimentation of the turbidite deposit led to an organic carbon burial flux comparable to the rate at which normal deep-sea sediment buries organic carbon over seven hundred years. Notably, finer sediment overlaying the turbidite layer acted as a cap, enhancing carbon sequestration within the trench. In contrast to nearby core GEO6, which documented over 11 turbidity currents, core S02 recorded only one event. Detailed bathymetric analysis highlights the crucial role of local topography in detecting and preserving turbidity currents. The insights gained from this study would advance our understanding of how turbidity currents shape and influence the deep ocean sedimentation.

The three ages of the European policy for productive investments

Across the EU sectoral policies, a variety of instruments are used to foster investments and to transform Europe’s productive capacities. Reading beyond the traditional bureaucratic and policy silos, this paper shows how such a composite repertoire of instruments crystalised, taking advantage of two complementary historical fieldworks. Using the sociological concept of ‘age’, we show how a European policy for productive investments emerged, supported by specific rationales and staff, to address episodes of budgetary constraints over investment policies. We first distinguish an ‘age of infrastructure’ (from the 1950s), where the first EEC bureaucrats in charge of these policies – mainly lawyers and engineers – designed loans strategies to continue reconstruction efforts, targeting heavy infrastructural investments in energy or transportation. Then, we show how in the 1970s context of rising budgetary tensions, economists urged their colleagues to take advantage of the Common Market to create European champions, through grants and co-financing, and by promoting SMEs as growth drivers: this marks the ‘integrative age’. Finally, from the 1990s, bureaucrats with a background in finance reoriented PI policies to overcome so-called ‘markets failures’ through loans, guarantees and equity, initiating an ‘age of leverage’ in EU public action. Here, the global access to (publicly subsidized) finance and the rise of derisking activities became a new standard. By capturing the way these successive policy ages concatenated and gave the EU Investor State its current shape, our approach accounts for both stability and change in EU policies.

Feasibility Study for Monitoring an Ultrasonic System Using Structurally Integrated Piezoceramics

This paper presents a new approach to monitoring ultrasonic systems using structurally integrated piezoceramics. These are integrated into the sonotrode at different points and with different orientations. The procedure for integrating the piezoceramics into the sonotrode and their performance is experimentally investigated. We examine whether the measured signal can be used to determine the optimal operating frequency of the ultrasonic system, if integrating several piezoceramics enables discernment of the current vibration shape, and if the piezoceramics can withstand the high strains caused by the vibrations in a frequency range of approximately 20–25 kHz. The signals from the piezoceramic sensors are compared to the real-time displacement at different points of the sonotrode using a 3D laser scanning vibrometer. To evaluate the performance of the sensors, different kinds of excitation of the ultrasonic system are chosen.

Selection of an Algorithm for Assessing the Verticality of Complex Slender Objects Using Semi-Automatic Point Cloud Analysis

Remote technologies, including laser scanning, are frequently employed to acquire data describing the geometric condition of engineering objects. The automation of point cloud processing becomes essential for promptly and reliably monitoring changes in their current shape. The article introduces a methodology for generating point clouds, focusing on detecting the shape of the object’s cross profiles and subsequently determining its inclination through simulations and real data recorded using terrestrial laser scanning technology. The simulations enabled the identification of variations in the characteristics of changes in the course of the axis of a slender structure, depending on the adopted calculation method. Point clouds derived from measurements of complex engineering objects facilitated the validation of the assumptions of the proposed methodology. The suggested solution enables the semi-automatic extraction of data from point clouds and the assessment of the geometric state of engineering object axes based on multi-temporal point clouds.

Tripolar configuration and pulse shape in cochlear implants reduce channel interactions in the temporal domain

The present study investigates effects of current focusing and pulse shape on threshold, dynamic range, spread of excitation and channel interaction in the time domain using cochlear implant stimulation. The study was performed on 20 adult guinea pigs using a 6-channel animal cochlear implant, recording was performed in the auditory midbrain using a multielectrode array. After determining the best frequencies for individual recording contacts with acoustic stimulation, the ear was deafened and a cochlear implant was inserted into the cochlea. The position of the implant was controlled by x-ray. Stimulation with biphasic, pseudomonophasic and monophasic stimuli was performed with monopolar, monopolar with common ground, bipolar and tripolar configuration in two sets of experiments, allowing comparison of the effects of the different stimulation strategies on threshold, dynamic range, spread of excitation and channel interaction. Channel interaction was studied in the temporal domain, where two electrodes were activated with pulse trains and phase locking to these pulse trains in the midbrain was quantified. The results documented multifactorial influences on the response properties, with significant interaction between factors. Thresholds increased with increasing current focusing, but decreased with pseudomonophasic and monophasic pulse shapes. The results documented that current focusing, particularly tripolar configuration, effectively reduces channel interaction, but that also pseudomonophasic and monophasic stimulation and phase duration intensity coding reduce channel interactions.

Omnipotent plant sources assisted green synthesis of Silver Nanoparticle - A promising Chemical Sensing tool

This article aims to analyze the various sensor applications of silver nanoparticles synthesized from green materials, particularly plant-based sources. The current shape in the field of nanotechnology is the synthesis of metal nanoparticles via environmentally friendly and more reliable green materials. The green route synthesis is found to be a promising method because of its congenial properties. It is economical, affable, and reproducible. Heavy metals have been dispersed widely in the environment, and they are well known for their virulent effects. Numerous methods are available to sense and detect those metals. The headway in the domain of nanotechnology is to synthesize AgNPs from green plants and to steer clear of the hazardous effects of metals. Efficacious synthetic routes via plant-mediated synthesized AgNPs open up easy and efficient sensing of hazardous metals in the environment. AgNPs have attracted many researchers because they have good biocompatibility and other outstanding properties. Remarkable electronic, catalytic, and optical properties have enabled AgNPs to be used as sensors in medical, biological, and chemical fields. This review highlights the application of PAGS-AgNPs as a chemical sensor for detecting heavy metals and organic compounds in the environment.

Large-Strain Surface Modeling Using Plasticity.

Modeling arbitrarily large deformations of surfaces smoothly embedded in three-dimensional space is challenging. We give a new method to represent surfaces undergoing large spatially varying rotations and strains, based on differential geometry, and surface first and second fundamental forms. Methods that penalize the difference between the current shape and the rest shape produce sharp spikes under large strains, and variational methods produce wiggles, whereas our method naturally supports large strains and rotations without any special treatment. For stable and smooth results, we demonstrate that the deformed surface has to locally satisfy compatibility conditions (Gauss-Codazzi equations) on the first and second fundamental forms. We then give a method to locally modify the surface first and second fundamental forms in a compatible way. We use those fundamental forms to define surface plastic deformations, and finally recover output surface vertex positions by minimizing the surface elastic energy under the plastic deformations. We demonstrate that our method makes it possible to smoothly deform triangle meshes to large spatially varying strains and rotations, while meeting user constraints.

THE EVOLUTION OF FINANCIAL INSTRUMENTS IN THE COMMON AGRICULTURAL POLICY IN LIGHT OF THE STRATEGIC PLAN FOR 2023-2027

The article presents the origins and key transformations of the EU’s Common Agricultural Policy (CAP) and the most significant factors that have influenced its current shape. It is shown that since its inception, the CAP has undergone significant changes involving both its goals and operational tools. It was found that over the years and under changing circumstances, the CAP has transformed from a policy aimed at increasing agricultural production and productivity into a tool that determines the development of rural areas and stimulates pro-environmental measures. The validity of this perspective is also supported by an analysis of the financial aspects of its functioning. In the context of the findings, the second part of the study characterizes the current shape of the Strategic Plan for the Common Agricultural Policy for 2023-2027 (CAP SP), which defines the main financial instruments for achieving the objectives of the CAP. It was found that compared to the previous programming period, significantly less funds were allocated to payments according to agricultural area (a decrease in the share from 43% to 35%), redirecting them to various types of payments related to pro-environmental measures. These changes are in line with the direction of the CAP’s evolution. However, the way in which additional payments are linked to the implementation of pro-environmental measures is debatable, creating numerous implementation problems for farmers. The result is a low share of eco-schemes in the payment applications submitted by farmers in 2023, which will reduce the amount of EU support they will absorb.

A Scientific “Forced Marriage” Takes on the Mysteries of the Loop Current

Decisionmakers need insights on how this powerful current shapes hurricanes, fisheries, energy supplies, and life in the Gulf of Mexico. An ambitious project to collect data and predict the current’s erratic behavior is compelling scientists to cross disciplines as well as borders.

Topology, Design, and Characteristics of a Modular, Dynamic 100 kA Surge Current Source With Adjustable Current Shape

Topology, Design, and Characteristics of a Modular, Dynamic 100 kA Surge Current Source With Adjustable Current Shape