Volume 69, Number 7-8, 2024
Theoretical, Mathematical, and Computational Physics
Using the Single-Term Haar Wavelet to Solve the State Variable Models of nth-Order CircuitsAbdolreza Momeni, Kazem Nouri, Leila Torkzadeh
This study is dedicated to investigating the utilization of the singleterm Haar wavelet approach for solving a state variable model of nth-order circuits. We provide the matrix calculations in a simplified manner to facilitate comprehension. Furthermore, a numerical mathematical illustration is presented, demonstrating the application of this technique to solving two first-order differential equations with both constant and variable coefficients. The study’s findings unequivocally demonstrate that the suggested approach surpasses previous methods, providing greater levels of accuracy and precision. Moreover, the single-term Haar wavelet approach is exceptionally userfriendly and efficient, necessitating only a minimal amount of processing resources.
Exploring Multiwave Solutions to the Integrable Combined pKP-BKP Equation in (3+1)-DimensionsZhou-Zheng Kang
Under consideration in the current paper is a new combined Painlevé integrable equation in (3+1)-dimensions, namely the potential Kadomtsev-Petviashvili equation incorporating the B-type Kadomtsev-Petviashvili equation (pKP-BKP equation). Maple symbolic calculations are made to present abundant multiwave solutions, which cover a breather-kink wave interacting with one-kink wave, and a breather-kink wave interacting with two-kink waves, as well as a breather-kink wave interacting with three-kink waves. Particularly, the dynamic and structural characteristics of some derived solutions are illustrated through some vivid 3D graphics.
Hetero-Bäcklund Transformation for a (2+1)-Dimensional Generalized Modified Dispersive Water-Wave SystemXin-Yi Gao, Yong-Jiang Guo, Wen-Rui Shan
This work is designed for a (2+1)-dimensional generalized modified dispersive water-wave system for the nonlinear and dispersive long gravity waves travelling along two horizontal directions in the shallow water of uniform depth, with our results as a hetero-Bäcklund transformation, from that system to a known generalized (2+1)-dimensional dispersive long-wave system. As for the height of the water surface and horizontal velocity of the water wave, our hetero-Bäcklund transformation depends on the shallow-water coefficients in that system.
Waiting Times for Sea Level Variations in the Port of Trieste: A Computational Data-Driven StudyGabriel Tiberiu Pană, Paul-Adrian Gogîță , Alexandru Nicolin-Żaczek
We report here a series of detailed statistical analyses on the sea level variations in the Port of Trieste using one of the largest existing data catalogues that covers more than a century of measurements. We show that the distribution of waiting times, which are defined here akin to econophysics, namely the series of shortest time spans between a given sea level $L$ and the next sea level of at least $L + \delta$ in the catalogue, exhibits a distinct scale-free character for small values of $\delta$. For large values of $\delta$, the shape of the distribution depends largely on how one treats the periodic components embedded in the sea level dataset. We show that direct analyses of the raw dataset yield distributions similar to the exponential distribution, while pre-processing the sea level data by means of a local averaging numerical recipe leads to Pareto-Tsallis distributions.
Physics of Elementary Particles and Fields
Expanding the Gluino Exclusion Limits Using Events with One Highly Energetic Final State Jet and Missing Transverse MomentumHammad Rasheed, Ioana Duminica
Multiple searches of theoretically hypothesized particles in Supersymmetry scenarios have been conducted through the years, many of which take place at the Large Hadron Collider (LHC) facility. A recent search of the ATLAS Collaboration [7] focuses on $\sqrt{s}=13$ TeV pp collisions characterized by highly energetic jets and missing transverse momentum, resulting in model-independent limits for selected Signal Regions and providing exclusion limits for squarks. In this paper, we reinterpret the observations in terms of exclusion limits on gluino pair production. Monte Carlo simulations of gluino pair production events are made, varying both the masses of gluino and neutralino. In the end, we present the results in the mass plane of $m_{\tilde{g}}$ vs. $m_{\tilde{g}} − m_{\tilde{\chi}_{1}^{0}}$, including the effect of various sources of uncertainty.
[7] ATLAS Collaboration, Search for new phenomena in events with an energetic jet and missing transverse momentum in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector, Phys. Rev. D 103 (2021) 112006.
Lasers, Plasmas, and Beam Physics
Electron Dynamics in a Relativistic Central Field Approach Associated with Laser Acceleration of ElectronsR. Iovănescu, R.P. Daia, E.I. Slușanschi, C.M. Ticoș
We perform 2D PIC simulations and observe different scenarios of electron trajectories trapped inside the bubble formed during the laser wakefield acceleration process (LWFA). The trajectories can close on the inside or on the outside of the bubble. The evolution of maximum energy of the injected electrons in both cases is evaluated. We propose an analytic approach based on a relativistic central field model for describing the attraction of electrons near the bubble edge and compare it with the simulations.
Condensed and Soft Matter Physics
Synthesis and Characterization of CoFe2O4 Nanoparticles and CoFe2O4@BaTiO3 Nanocomposites for Biomedical ApplicationsV. Vințeler, R. Dudric, R. Bortnic, A. Szatmari, L. Barbu-Tudoran, R. Tetean
Cobalt ferrite magnetic nanoparticles (CFO) of around 9 nm were synthesized with the solvothermal method. The CFO particles were covered with a barium titanate (BTO) shell at a 1:1 CFO:BTO ratio, via a sol-gel synthesis, to form CFO@BTO nanocomposites. X-Ray Diffraction (XRD) studies reveal the presence of only the expected CFO and BTO phases. Scanning and Transmission Electron Microscopy (SEM, TEM) images show the thorough covering with the BTO shell. Energy-Dispersive X-ray spectroscopy (EDX) mapping was used to analyze the elemental composition of the nanocomposites. Magnetic characterization shows high saturation magnetization and low coercive field at 300 K, suitable for biomedical applications.
A Study on the Impact of Magnetic Nanoparticles on Dye Loaded Wastewater – the Case of Rhodamine BA.R. Fanaru, M. Grigoras, G. Ababei, L. Oprica, D. Creanga
The utilization of magnetic nanoparticles as wastewater cleaners was studied. Magnetite, synthesized and characterized by usual methods was delivered to 10 µM Rhodamine B loaded wastewater model, under UV-C irradiation and hydrogen peroxide supply. The quantification of dye degrading for different time intervals emphasized first order kinetics of Rhodamine B adsorption on 8 g/L magnetic nanoparticles.
Structure and Wet-Sliding Characterization of a Laser Powder Bed Fusion Ti-6Al-4V Biomedical Alloy: Effect of Laser Surface ModificationB.V. Efremenko, I. Petryshynets, Y.G. Chabak, V.I. Zurnadzhy, K. Wu, V.G. Efremenko, V.I. Fedun, F. Kromka, V.V. Kulyk, E.V. Tsvetkova
The effect of laser modification on the structure and wet (Simulated Body Fluid)-sliding behaviour of a Laser Powder Bed Fusion alloy Ti-6Al-4V was studied. The scanning of 400 W fiber laser with a speed of 10 mm·s–1 led to a surface melting with an increase in hardness (780–820 HV) and 20%-decrease in wear. Under the scanning speeds of 40–60 mm·s–1 the surface was refined almost without melting to provide a 7–8% increase in hardness/wear resistance accompanied by a decrease in the friction coefficient.
Magnetic Properties and Hysteresis Behavior of Mixed Spin Multilayer: A Monte Carlo StudyS. Zouhair, M. Bourass, R. Aharrouch, E. Dahbani, N. Hachem, M. El Bouziani
The hysteresis behavior and magnetic properties of the Ising multilayer system, consisting of spin − 1/2 and spin − 5/2, are examined by the use of the Monte Carlo simulation. We have reported the impact of the size and the exchange interactions, as well as the crystal field on the thermal total, partial magnetization and the phase diagram. We have found some interesting results such as first- and second-order phase transitions and critical end-points. To complete this study, we have illustrated and analyzed the effect of longitudinal magnetic field on the hysteresis behavior of the system.
Controlled Synthesis of C70 Fullerene Micro/NanotubesU.K. Makhmanov, B.A. Aslonov, S.A. Esanov, A. Shukurov, T.A. Chuliyev
The physical features of the synthesis and further growth of C70 fullerene micro/nanotubes in the volume of an evaporating drop on a substrate surface have been studied. The morphological and optical characteristics of one dimensional C70 nanostructures have been determined. The possibility of controlling the geometric dimensions of the synthesized C70 tubes by changing both the concentration of C70 in the initial drop and the temperature of the substrate used was demonstrated experimentally.
Environmental and Earth Physics
Gross Alpha/Beta Radioactivity of Drinking Water and Relationships with Quality Parameters of Water from Alba County, RomaniaC.I. Tăban, A. Sandu, S. Oancea, M. Stoia
Drinking-water is considered one of the existing exposure situations to radiation, which involves a level of risk for human health. Thus, its radioactivity is evaluated to keep exposure “as low as reasonably achievable”. Based on monitoring data sets (2017–2023) for six physical-chemical indicators of drinking water quality and total radioactivity expressed by gross alpha activity, gross beta activity and Radon222 content, we evaluated the correlations, relationships, predictors (water source, locality, year), regional variations and potential baseline patterns using statistical analysis and models. The obtained model shows that drinking water sources and localities are factors with significant effect on nitrates concentration and total hardness, ranking sources in the order: well > spring > municipal distribution system; the rank order of drinking water sources based on the concentration of Radon-222 is spring > well > municipal distribution system; locality was found the best predictor for radioactivity; significant correlations were found between gross alpha and gross beta, between gross beta and Radon-222, and between ammonia, nitrates, nitrites and total hardness. The establishment of a baseline pattern for gross alpha activity is a public health goal that can be achieved through performance monitoring of natural radioactivity in water, useful for preparedness in case of a nuclear event.
UV-C Priming Enhances Water Stress Tolerance in Broccoli (Brassica Oleracea, L.) and Its Germination RateE. Martinez, J. Alvarez, M. Florez, V. Carbonell, J. Gutierrez, F. Alonso, C. Hernandez
Germination of broccoli seeds exposed to UV-C radiation (priming) for a 30-minute period and tolerance to water stress was evaluated. These findings suggest that the adverse effect of drought on the germination rate can be circumvented by seeds primed with a UV-C radiation at a wavelength of 254 nm during 30 min.
Applied and Interdisciplinary Physics
PID-Based Temperature Stabilization for Silicon Photomultipliers Using Thermoelectric Cooling DevicesP. C. Boboc, O. E. Huțanu, A. M. Bragadireanu
In this paper, we present a temperature stabilization system for Silicon Photomultipliers (SiPMs) using thermoelectric cooling devices controlled by a PID (Proportional-Integral-Derivative) controller. Maintaining a stable temperature for SiPMs and their associated front-end electronics is crucial for achieving consistent gain and noise minimization. Our system employs three CP1881-222 thermoelectric coolers per module and is managed by two ATMega1284p microcontrollers. One microcontroller handles the PID control routine, while the other functions as a TCP/IP client. The temperature is monitored using PT100 sensors connected via MAX31865 RTD converters, ensuring precise measurements. The PID algorithm efficiently corrects temperature deviations, maintaining an error margin of approximately ±0.2°C. The system has been successfully deployed in the HASC subdetector of CERN’s NA62 experiment, where it maintains the SiPM temperature at 20.5°C, enhancing the subdetector’s performance. The modular design of our PID controller system allows for adaptability to various experimental setups requiring precise temperature control.
Mechanical Properties of Pb–0.7%Sn–0.08%Ca Positive Grid Alloy for Lead-Acid BatteriesV. Dzenzerskiy, S. Tarasov, O. Sukhova, V. Ivanov
The effects of casting procedure and ageing time on the tensile properties of Pb–0.7%Sn–0.08%Ca positive grid alloy for lead-acid batteries were investigated. As a preheating temperature of a mold during casting increases from 40°C to 170°C, ultimate tensile strength decreases, but elongation increases due to the changes in the grain structure of the alloy. Prolongation of ageing time up to 32 days causes the increase in strength and decrease in elongation, with higher ageing rate observed during first 15 days.
SolidWorks Simulation Approach for Concrete Pillars Consolidation with CFRP WrapsCristian Ştefan Dumitriu
This paper presents the results of the Finite Element Analysis using SolidWorks simulation of the strengthening effect of the CFRP wraps applied to the bottom of concrete pillars bearing uniaxial compression forces. The benefits of using CFRP wrap have been emphasized by analyzing the resulting values of Displacement, Strain, and Factor of Safety.
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