Physical Basis Research Articles

Enhancing Student Learning Activities Through Interactive Learning Design in Basic Physics 1

Enhancing Student Learning Activities Through Interactive Learning Design in Basic Physics 1

A Progressive Loss Decomposition Method for Low-Frequency Shielding of Soft Magnetic Materials

Energy loss in shielding soft magnetic materials at low frequencies (1–100 Hz) can cause fluctuations in the material’s magnetic field, and the resulting magnetic noise can interfere with the measurement accuracy and basic precision physics of biomagnetic signals. This places higher demands on the credibility and accuracy of loss separation predictions. The current statistical loss theory (STL) method tends to ignore the high impact of the excitation dependence of quasi-static loss in the low-frequency band on the prediction accuracy. STL simultaneously fits and predicts multiple unknown quantities, causing its results to occasionally fall into the value boundary, and the credibility is low in the low-frequency band and with less data. This paper proposes a progressive loss decomposition (PLD) method. Through multi-step progressive predictions, the hysteresis loss simulation coefficients are first determined. The experimental data of the test ring verifies the credibility of PLD’s prediction of the two hysteresis coefficients, improving the inapplicability of the STL method. In addition, we use the proposed method to obtain the prediction results of the low-frequency characteristics of the loss of a variety of typical soft magnetic materials, providing a reference for analyzing the loss characteristics of materials.

Approximation of the Absorption Spectrum of Indium Phosphide in the Context of Simulation of the Process of Sensitivity Enhancement

Examines the fundamental rights of Phosphide of India, legitimized by Tellur and, in the last resort, compensated for. Data on the composition of four high-quality images of the InP: Cu photoelectronic spectrum are presented in the individual layers. The work is characterized by the semi-empiric approach to photoconduction of InP: Cu oxide films. It is concluded that the photoresistance Iph (α(ћω)) was analytically approximated as the function of the experimental-complete spectral distribution of the coefficiency phosphorus india. It is proposed to use five approximating functions with the aim of analyzing the coefficient of absorption of Indian phosphorus α(ћω). Completed 5 locations with different signs of median isolation. On the basis of analytical amplitudes, the complete analytical amplitude Iph(α(ћω)) is modelled. Analogously, five conclusions were drawn that indicate a sign of median isolation. Five non-stationary measures of IF photometry have been taken (as two functions: co-efficiency of exposure, as photo energy functions, and time-consuming observations) in normal situations. The answer to the question is the most mathematical and physical solution of the proximate function α(ћω). Obviously, it shows that this the degree of variance is optimal for its implementation (inclusion of this degree of variance in the structure Iph = f(α) and α = f(ћω)) of the complete analytical description of the process photoconductivity. It should be noted that subsequent research may be based on the establishment of physical bases of photoconductivity in the short wave of fundamental transfers of phosphorus from India, as well as research into the properties of air on the high InP: Cu layer, with its stability and stability.

Effect of Pregenomic RNA on the Mechanical Stability of HBV Capsid by Coarse-Grained Molecular Simulations.

Hepatitis B virus (HBV) is a double-stranded DNA virus, but its life cycle involves an intermediate stage, during which pregenomic RNA (pgRNA) is encapsulated in the capsid and then reverse-transcribed into the minus DNA strand. These immature HBV virions are the key target for antiviral drug discovery. In this study, we investigate the flexibility and mechanical stability of the HBV capsid containing pgRNA by employing residue-resolved coarse-grained molecular dynamics simulations. The results showed that the presence of pgRNA tends to decrease the overall flexibility of the capsid. In addition, the symmetrically arranged subunits of the capsid show asymmetry in the dominant modes of the conformational fluctuations with or without the presence of pgRNA. Furthermore, the simulations revealed that the presence of pgRNA enhances the overall mechanical stability of the virion particle. Electrostatic interactions between the disordered CTD of capsid and pgRNA were found to play a crucial role in modulating viral mechanical stability. Decreasing the electrostatic interactions by CTD phosphorylation or high salt concentration significantly reduces the mechanical stability of the HBV capsid containing pgRNA. Finally, the 2-fold symmetric sites have been proposed to be the most vulnerable to rupture during the initial stages of capsid disassembly. These findings could enhance our understanding of the physical basis of viral invasion and provide valuable insights into the development of antiviral drugs.

ST40 electromagnetic predictive studies supported by machine learning applied to experimental database

Nuclear fusion is entering the era of power plant-scale devices, which are now undergoing extensive studies to support the design phase. Plasma disruptions pose a high risk to these classes of devices because of the large stored thermal and magnetic energy which might jeopardize machine integrity and availability. Therefore, disruptions within these devices must be virtually eliminated, and any disruptions which do happen must be highly mitigated. However, the characterisation, prediction and technology used to mitigate disruptions is still an area of active development. In this paper, the authors investigate the disruptions within ST40, with particular attention at the identification of causes and effects associated with disruptions, both from a physics basis and an engineering standpoint. This paper aims at presenting preliminary predictive analyses of ST40 plasma scenarios by exploiting Machine Learning techniques applied to an experimental database populated by plasma pulses executed during the ST40 2021–2022 experimental campaign. The database contains both disrupted and non-disrupted pulses. Using Machine Learning, common features within disruptions are automatically classified and identified, mapping the controllable operational space in terms of plasma displacement and variation of specific plasma internal parameters. The classification was validated by benchmarking the numerical reconstruction of the plasma dynamics with experimental data recovered from the plasma diagnostics. Subsequent Machine Learning analyses allowed the extrapolation of new disrupted plasma configurations for preliminary predictive simulations of the plasma column displacement. Thanks to the numerical simulations performed in MAXFEA environment, it is possible to investigate the plasma vertical displacement both during disrupted and regularly terminated plasma scenarios and to provide lessons to be learnt for the next ST40 experimental campaign and for the design of future ST devices.

Decarbonizing the global steel industry in a resource-constrained future-a systems perspective.

Decarbonizing the global steel industry hinges on three key limited resources: geological carbon storage, zero-emission electricity and end-of-life scrap. Existing system analysis calls for an accelerated expansion of the supply of these resources to meet the assumed ever-increasing steel demand. In this study, we propose a different view on how to decarbonize the global steel industry, based on the principle that resource supply can only expand in line with historical trends and actual construction plans. Our analysis shows that global steel production cannot grow any further within a Paris-compatible carbon budget, resulting in a shortfall of approximately 30% against 2050 demand. This trajectory involves the phasing out of blast furnaces, along with strong growth in scrap recycling and hydrogen-based production. These findings highlight critical yet often overlooked challenges: (i) reducing excess demand while providing essential services, (ii) producing high-grade steel through upcycling scrap, and (iii) ensuring an equitable distribution of limited production across the globe. These perspectives contrast with those of the current agenda, which largely emphasizes the need to invest in new production technologies. Grounded in a physical basis, this analysis offers a complementary perspective for a more balanced debate in policymaking and industrial strategy. This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Electromagnetic radiation of granite under dynamic compression

To elucidate the characteristics and mechanism of electromagnetic radiation in granite under impact loading, based on the quasi-static compression tests, this paper conducts dynamic compression experiments on granite using Hopkinson pressure bar and one-stage light-gas gun as loading methods. Combined with experimental and theoretical analyses, the relationship between mechanical and electromagnetic responses under impact loads of different intensities, and the time-domain signals of electromagnetic radiation generated by a single crack under different strain rates are studied. The intensity and frequency of electromagnetic radiation increase with the increasing compressive strain rate. According to the thermal activation theory, it reveals the microscopic mechanism of the transition from intergranular microcracks to transgranular microcracks in terms of strain sensitivity. It also serves as the physical basis for the increase in electromagnetic radiation intensity amplitude and frequency with increasing compressive strain rate. Transgranular microcracks are the primary cause of electromagnetic radiation generated by fractures.

An instructional lab apparatus for quantum experiments with single nitrogen-vacancy centers in diamond

Hands-on experimental experience with quantum systems in the undergraduate physics curriculum provides students with a deeper understanding of quantum physics and equips them for the fast-growing quantum science industry. Here, we present an experimental apparatus for performing quantum experiments with single nitrogen-vacancy (NV) centers in diamond. This apparatus is capable of basic experiments such as single-qubit initialization, rotation, and measurement, as well as more advanced experiments investigating electron–nuclear spin interactions. We describe the basic physics of the NV center and give examples of potential experiments that can be performed with this apparatus. We also discuss the options and inherent trade-offs associated with the choice of diamond samples and hardware. The apparatus described here enables students to write their own experimental control and data analysis software from scratch, all within a single semester of a typical lab course, as well as to inspect the optical components and inner workings of the apparatus. We hope that this work can serve as a standalone resource for any institution that would like to integrate a quantum instructional lab into its undergraduate physics and engineering curriculum.

A supramodal thorough account of the Molyneux question

In this paper, we want to tackle the Molyneux question thoroughly, by addressing it in terms of both ordinary perception and pictorial perception: if a congenitally blind person recovered sight, could she recognize visually the 3D shapes she already recognized tactilely, both when such shapes are given to her directly and when they are given to her pictorially, i.e., as depicted shapes? We want to claim that empirical evidence suggests that the question can be positively answered in both cases. For in the first case, such evidence shows that perception of 3D shapes is supramodal; namely, it can be equivalently achieved in different sense modalities, notably touch and vision, independently of the sensory input such shapes are accessed. While in the second case, such evidence shows that one can satisfy both in vision and in touch the condition for depicted shapes, which are typically not where the perceiver is, to be grasped by that perceiver in a picture’s subject, i.e., what the picture presents. This condition states that the picture’s vehicle, i.e., the typically 2D physical basis of a picture, is enriched by adding to its properties the 3D grouping properties that allow for a figure/ground segmentation to be performed in that vehicle’s elements.

METHOD FOR INCREASING THE RESOLVING POWER OF AN OPTICAL MICROSCOPE

Purpose. Increasing the resolution and magnification of the optical microscope to expand the possibilities of observation and research in various fields of science and technology. Research methods. Theoretical, experimental. Results. A comparative analysis of the human eye as an optical system and the optical system of a microscope was carried out. It was found that these systems have a similar nature, namely, a separate image of two closely located objects. If we consider the human eye as a light-sensitive matrix, then to determine the resolution of the eye, it is necessary to use the ratio of the average value of the number of light-sensitive elements (rods and cones) that fall on the retina to the area of the retina itself (for the human eye, it is 0.1...0.2 mm). For an optical microscope, it is necessary to separate the concepts of “resolution” and “magnification”. We also mentioned the physical basis of the resolution of optical microscopes. It was shown that for a dry lens the resolution limit for λ = 555 nm is 0.3 μm. One of the ways to increase the resolution is the use of immersion fluids. However, in certain studies its use is inappropriate or impossible. If instead of conventional illuminators (maximum intensity at λ = 555 nm) you use ultraviolet ones (λ = 380…410 nm), then the resolution can be increased several times, and the increase is up to 2000. The disadvantage of using UV illuminators is that it is necessary to use a light filter with direct observation or a monitor with an indirect method to avoid negative effects on the observer’s vision. Scientific novelty. The increased resolution and magnification of the optical microscope when using coherent light sources instead of immersion fluids provides more detailed scientific information and facilitates its processing. Practical value. Using the results of our research allows you to get a more informative image when using coherent light sources.

Laboratory Management; Challenges and Opportunities in FkipUhamka

This study aims to analyze the management of basic physics laboratories at UniversitasMuhammadiyah Prof DR HAMKA and its impact on user performance and satisfaction. Optimal management of basic physics laboratories is very important to support the learning process and student practicums. This study uses a descriptive method with a quantitative approach, where data is collected through questionnaires distributed to lecturers and students who use the laboratory. The results of the study indicate that the management of basic physics laboratories at UniversitasMuhammadiyah Prof DR HAMKA has been running well, but there are still several aspects that need to be improved, such as equipment maintenance, additional facilities, and improving work safety. Data analysis shows that there is a significant relationship between laboratory management and user performance and satisfaction. Good management will improve the efficiency of laboratory use, which in turn will improve academic performance and user satisfaction. Based on the findings, several suggestions are given for further improvement, including planning for periodic maintenance, adding facilities, improving laboratory technician skills, and regular monitoring and evaluation. The implementation of these suggestions is expected to improve the quality of basic physics laboratory management at UniversitasMuhammadiyah Prof. DR HAMKA.

A Theoretical Model for the Hydraulic Permeability of Clayey Sediments Considering the Impact of Pore Fluid Chemistry

The chemistry of the pore fluid within clayey sediments frequently changes in various processes. However, the impacts of pore fluid chemistry have not been well included in the hydraulic permeability model, and the physical bases behind the salinity sensitivity of the hydraulic permeability remains elusive. In this study, a theoretical model for the hydraulic permeability of clayey sediments is proposed, and impacts of the pore fluid chemistry are quantitatively considered by introducing electrokinetic flow theory. Available experimental data were used to verify the theoretical model, and the verified model was further applied as a sensitivity analysis tool to explore more deeply how hydraulic permeability depends on pore fluid chemistry under different conditions. Coupling effects of pore water desalination and the effective stress enhancement on the hydraulic permeability of marine sediments surrounding a depressurization wellbore during hydrate production are discussed. Results and discussion show that the hydraulic permeability reduction is significant only when the electric double layer thickness is comparable to the characteristic pore size, and the reduction becomes more obvious when the ion mobility of the saline solution is smaller and the surface dielectric potential of clay minerals is lower. During gas hydrate production in the ocean, the salinity sensitivity of the hydraulic permeability could become either stronger and weaker, depending on whether the original characteristic pore size of marine sediments is relatively large or small.

Comprehensive assessment of factors affecting the operational reliability of low-voltage asynchronous electric motors of a coal mining complex

THE RELEVANCE of this study lies in solving the problem of reliable functioning of elements of energy systems and ensuring their effective operation during open-pit mining. The paper presents a methodological approach that allows us to assess the level of reliability of low-voltage asynchronous electric motors in a coal mine with complex mining, geological and climatic conditions of production. THE PURPOSE of the work is to quantify the operational factors affecting the service life of an asynchronous electric motor with a short-circuited rotor. Attention is focused on how influencing factors, different in physical basis, among which electrical parameters are highlighted – the coefficient of voltage asymmetry in the reverse sequence, the coefficients of harmonic voltage components and environmental parameters – temperature, air humidity and dustiness, affect the dynamics of changes in the service life of an asynchronous electric motor. Asynchronous electric motors used at one of the enterprises of JSC SUEK in the Trans-Baikal Territory are considered as an object of research. METHODS. The main tool for the implementation of research tasks is computer modeling based on the Matlab software package. RESULTS. The studies were performed on an asynchronous electric motor with a short-circuited rotor with Ph = 3 kW, rated speed 1500 rpm. The simulation of the operating mode of the electric motor under study was performed by changing the experimental parameters: the values of the total coefficient of harmonic voltage components (KU) – from 4 to 12% with a range of 2%; the values of the voltage asymmetry coefficient in the reverse sequence (K2U) – from 0 to 4% with a range of 1%; the ambient temperature (∆Tокr) – from -30°C to +30°C with a range of 10°C; air humidity values (Vc) – 20% and 60%; dust thermal conductivity coefficient values (Kт) – 0,12 and 0,28. Based on the obtained research results, diagrams are constructed that clearly illustrate the dynamics of changes in the service life of an asynchronous electric motor depending on the combination of influencing factors. CONCLUSION. The trends in solving the issues of reliable functioning of a coal mining enterprise with the presence of asynchronous electric motors and ensuring their efficient operation are the most priority, mainly focused on maintaining the stability of technological processes and maintaining the production volumes of a coal mining enterprise. The stability of the electric motor to certain influencing factors is estimated and their critical values are established. Recommendations on the use of asynchronous electric motors are formulated, taking into account their operating conditions.

Investigating the correlation between flow dynamics and flow-induced voltage generation

The conversion of water current to voltage generation through graphene has gained interest in both basic physics and applications such as sensors and electricity generation systems. However, many aspects of the mechanism remain unclear. Recently, quantum-based momentum transfer theories have been reported, but these often do not account for flow conditions. In this study, we investigated the correlation between the flow conditions of a liquid medium and the electrical conduction of graphene through experiments and numerical calculations. Our results suggest that the necessary condition is that the flow must be neither irregular nor purely laminar; instead, graphene responds to the transition process of the fluid. This finding supports the extension of current theories and presents valuable insights for both basic science and industrial applications.

Reentrant DNA shells tune polyphosphate condensate size

The inorganic biopolymer polyphosphate (polyP) occurs in all domains of life and affects myriad cellular processes. A longstanding observation is polyP’s frequent proximity to chromatin, and, in many bacteria, its occurrence as magnesium (Mg2+)-enriched condensates embedded in the nucleoid region, particularly in response to stress. The physical basis of the interaction between polyP, DNA and Mg2+, and the resulting effects on the organization of the nucleoid and polyP condensates, remain poorly understood. Here, using a minimal system of polyP, Mg2+, and DNA, we find that DNA can form shells around polyP-Mg2+ condensates. These shells show reentrant behavior, that is, they form within a window of Mg2+ concentrations, representing a tunable architecture with potential relevance in other multicomponent condensates. This surface association tunes condensate size and DNA morphology in a manner dependent on DNA length and concentration, even at DNA concentrations orders of magnitude lower than found in the cell. Our work also highlights the remarkable capacity of two primordial inorganic species to organize DNA.

Fossil biocalcite remains open to isotopic exchange with seawater for tens of millions of years

Fossilized remains of marine calcifiers constitute the physical basis for reconstructions of both deep ocean and sea-surface temperatures going back millions of years, but paleoclimate records derived from their isotope and trace-element chemistry can be biased by diagenesis. Experiments simulating diagenesis in the presence of an 18O-rich seawater analogue were conducted with modern and 14 Myr old foraminifera (Ammonia sp.) tests to investigate their relative susceptibility to oxygen isotope exchange. The fossilized tests were of exceptional preservation and similar to modern tests in terms of structure and crystalline organization, but had experienced partial loss of embedded organic structures, thus a priori offering fewer preferential pathways for porewaters to penetrate the tests. NanoSIMS imaging revealed that oxygen isotope exchange was pervasive in fossil tests, with isotopic exchange occurring at approximately half the rate of modern tests. The results unequivocally show that fossil biocalcites are metastable and remain more susceptible to isotope exchange than abiotic calcites millions of years after sedimentation and burial.

Membrane Composition Allows the Optimization of Berberine Encapsulation in Liposomes.

Berberine (BBR) is a natural molecule with noteworthy pharmacological properties, including the prevention of antibiotic resistance in Gram-negative bacteria. However, its oral bioavailability is poor, thus resulting in an impaired absorption and efficacy in humans. In combination with other drugs, liposomes have been shown to enhance the availability of the drug, representing a smart delivery system to target tissues and reduce negative side effects. To date, there is a lack of studies on BBR and liposomes that enable the rationalization and molecular-based design of such formulations for future use in humans. In this work, the encapsulation of BBR into liposomes is proposed to overcome current limitations using a combination of experimental and computational assays to rationalize the membrane composition of liposomes that maximizes BBR encapsulation. First, the encapsulation efficiency was measured for several membrane compositions, revealing that it is enhanced by cholesteryl hemisuccinate and, to a lesser extent, by cholesterol. The physical basis of the BBR encapsulation efficiency and permeability was clarified using molecular dynamics simulation: using the lipid composition, one can tune the capability of membranes to attract, i.e., to adsorb, the molecules onto their surface. Overall, these findings suggest a rational strategy to maximize the encapsulation efficiency of liposomes by using negatively charged lipids, thus representing the basis for designing delivery systems for BBR, useful to treat, e.g., antibiotic resistance.

Filamentous fungal pellets as versatile platforms for cell immobilization: developments to date and future perspectives

Filamentous fungi are well-known for their efficiency in producing valuable molecules of industrial significance, but applications of fungal biomass remain relatively less explored despite its abundant and diverse opportunities in biotechnology. One promising application of mycelial biomass is as a platform to immobilize different cell types such as animal, plant, and microbial cells. Filamentous fungal biomass with little to no treatment is a sustainable biomaterial which can also be food safe compared to other immobilization supports which may otherwise be synthetic or heavily processed. Because of these features, the fungal-cell combination can be tailored towards the targeted application and be applied in a variety of fields from bioremediation to biomedicine. Optimization efforts to improve cell loading on the mycelium has led to advancements both in the applied and basic sciences to understand the inter- and intra-kingdom interactions. This comprehensive review compiles for the first time the current state of the art of the immobilization of animal, yeast, microalgae, bacteria, and plant cells in filamentous fungal supports and presents outlook of applications in intensified fermentations, food and biofuel production, and wastewater treatment. Opportunities for further research and development were identified to include elucidation of the physical, chemical, and biological bases of the immobilization mechanisms and co-culture dynamics; expansion of the cell-fungus combinations investigated; exploration of previously unconsidered applications; and demonstration of scaled-up operations. It is concluded that the potential exists to leverage the unique qualities of filamentous fungus as a cellular support in the creation of novel materials and products in support of the circular bioeconomy.

Kepler’s problem of a two-body system perturbed by a third body

One of the most important problems in basic physics and astronomy is studying the motion of planets, satellites, and other celestial bodies. The solution to the two-body problem enables astronomers to predict the orbits of the Moon, satellites, and spaceships around the Earth. The general analytic solution for the three-body problem stands unsolved except in some special cases. This reduces the problem to a two-body problem. In this work, the authors present a closed-form approach to the three-body problem theoretically and numerically based on particle–particle vector analysis. The theoretical approach, which is based on the real Moon–Sun–Earth problem information, illustrates the perturbation of the Moon in the Sun–Earth problem and shows an expected orbital motion with a perturbation in the Sun–Earth orbit due to the revolution of the Moon. The numerical investigation uses the same information to study the same problem and calculate the angular momentums of each pair of objects. The two solutions show good agreement with the well-known Earth-Moon and Sun–Earth momentums. The Moon–Sun orbit is close to an elliptic shape with angular momentum of about 3.27 × 1038 J.s. This approach is the key to future studies for n-body problem solutions.

Virulence-linked adhesin drives mutualist colonization of the bee gut via biofilm formation.

Bacterial biofilms are stable multicellular structures that can enable long term host association. Yet, the role of biofilms in supporting gut mutualism is still not fully understood. Here, we investigate Snodgrassella alvi , a beneficial bacterial symbiont of honey bees, and find that biofilm formation is required for its colonization of the bee gut. We constructed fifteen S. alvi mutants containing knockouts of genes known to promote colonization with putative roles in biofilm formation. Genes required for colonization included staA and staB , encoding trimeric autotransporter adhesins (TAAs) and mltA , encoding a lytic transglycosylase. Intriguingly, TAAs are considered virulence factors in pathogens but support mutualism by the symbiont S. alvi. In vitro , biofilm formation was reduced in Δ staB cells and abolished in the other two mutants. Loss of staA also reduced auto-aggregation and cell-cell connections. Based on structural predictions, StaA/B are massive (>300 nm) TAAs with many repeats in their stalk regions. Further, we find that StaA/B are conserved across Snodgrassella species, suggesting that StaA/B-dependent colonization is characteristic of this symbiont lineage. Finally, staA deletion increases sensitivity to bactericidal antimicrobials, suggesting that the biofilm indirectly buffers against antibiotic stress. In all, the inability of two biofilm-deficient strains (Δ staA and Δ mltA ) to effectively mono-colonize bees indicates that S. alvi biofilm formation is required for colonization of the bee gut. We envision the bee gut system as a genetically tractable model for studying the physical basis of biofilm-mutualist-gut interactions.