https://jpst.irost.ir/ Journal of Particle Science and Technology en daily 1 Mon, 01 Dec 2025 00:00:00 +0330 Mon, 01 Dec 2025 00:00:00 +0330 https://jpst.irost.ir/article_1644.html Due to its high strength and corrosion resistance, aluminum alloy 7055 is widely used in aerospace structures. However, its susceptibility to stress corrosion cracking (SCC) limits its performance. In this study, the combined effects of zirconium (Zr) addition and retrogression and re-aging (RRA) heat treatment on the microstructure, grain boundary precipitates, and stress corrosion resistance (SCR) of 7055 aluminum alloy were investigated. For property evaluation, microstructural characterization was carried out using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), while mechanical and stress corrosion tests were conducted according to ASTM standards. The results showed that Zr addition refined the grains and promoted the formation of Al3Zr particles within the matrix, inhibiting grain growth during heat treatment. RRA treatment accompanied by Zr addition improved the mechanical strength from 528 to 608 MPa and increased the stress corrosion resistance from 68 to 96 %. The combined effect of Zr addition and RRA treatment resulted in a more stable microstructure, with improved strength and resistance to stress-corrosion cracking. https://jpst.irost.ir/article_1716.html Researchers have considered powder compaction modeling to predict necessary compaction pressure at desirable density. This paper presented cold compaction modeling of titanium powder under high-power longitudinal ultrasonic vibration based on experimental tests. Superimposing high-frequency, high-power mechanical vibration on the compaction process could improve green density and density distribution. For this purpose, a special ultrasonic assisted cold compaction setup was designed and fabricated. CP titanium powder with size of <45µm compacted (up to 900MPa) at different ultrasonic powers (0, 100W, 150W, 200W, 300W). Then, a mathematical formulation was presented for ultrasonic-assisted cold powder compaction consisting of four terms: initial density, particle rearrangement, particle deformation, and ultrasonic vibration effects. The results showed that the presented mathematical model could predict accurately green compact density as a function of compaction pressure and ultrasonic power. https://jpst.irost.ir/article_1687.html Porous lithium-titanium oxide (pLT) was produced by the combustion synthesis method. Based on the XRD pattern, the as-synthesized powder phase was Li2TiO3. The carbon dots were incorporated onto the lithium titanate sponge (pLT-CD) using the microwave method and natural precursors. Two synthesized structures were used to remove methylene blue from wastewater. A morphological comparison of pLT and pLT-CD was performed using field emission scanning electron microscopy. Elemental mapping of the pLT-CD composite was used to investigate the dispersion of CD on pLT and its stability in aqueous media. The experiments of methylene blue removal by adsorbents were designed using the Taguchi method. The effect of pH, time, temperature, and methylene blue concentration on the treatment process by pLT and pLT-CD was studied. The maximum removal percentage was observed at pH 8, room temperature, 10 min, and 40 ppm dye concentration on the pLT-CD composite adsorbent. The adsorption equilibrium was better described by the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces. Kinetic results followed a pseudo-second-order model, with pLT-CD showing a higher adsorption rate due to enhanced surface interactions and increased active sites. Adsorbent recovery was performed by UV-Vis irradiation on the saturated adsorbent to decompose the adsorbed dye. An efficiency drop of about 20 and 13.60 % was observed for pLT and pLT-CD, respectively, after four consecutive cycles https://jpst.irost.ir/article_1691.html Thermal management of high-power X-ray rotating anodes is strictly constrained by the intense, localized heat fluxes generated during brief exposure times. This study proposes the integration of a lithium-based rotating pulsating heat pipe (RPHP) into the anode and investigates its transient thermal-hydraulic performance using a volume of fluid (VOF) multiphase model, which is heavily influenced by both extreme centrifugal forces and the intense heat flux applied during the exposure time. The results reveal a fundamental thermodynamic trade-off governing the optimal rotational speed: while higher rotational speeds enhance internal fluid circulation as well as latent and sensible heat transport, they simultaneously generate massive hydrostatic pressures that cause a significant transient delay in the phase-change (boiling) process. Consequently, the maximum allowable exposure time exhibits a non-monotonic dependence on the rotational speed. A case study based on the RAD-14 X-ray tube was investigated with a heat input of 20 kW on a minimum focal spot size (0.3 mm). A critical temperature limit of 2200 K was defined to evaluate and compare the allowable exposure times across different configurations. Compared to a conventional solid anode (which is limited to an exposure time of 0.436 s), the RPHP integration at 8500 rpm achieves optimal thermal performance, extending the allowable exposure time to 0.706 s (a 62 % increment). However, further increasing the speed to 10000 rpm exacerbates the pressure-induced boiling retardation, leading to an exposure time of 0.619 s (a 42 % increment relative to the solid base, but a 12 % reduction compared to the 8500 rpm peak). https://jpst.irost.ir/article_1688.html In this study, the preparation and identification of Cu2S nanoparticles were carried out using the microwave method, and the effect of irradiation time, power, and surfactant on particle size was investigated. The sample was characterized by XRD measurements, field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR), and ultraviolet-visible (UV-Vis). Also, the results of FE-SEM on nanoparticles prepared with four surfactants, EDTA, sorbitol, citric acid, and PEG 400, showed that nanoparticles synthesized with the PEG 400 surfactant have the smallest size. Then, the effect of microwave power on the size of Cu2S nanoparticles was investigated at three powers of 700, 500, and 900 W. The FE-SEM results showed that Cu2S nanoparticles have the smallest size at 500 W. To investigate the effect of time on the size of Cu2S nanoparticles, the experiments were repeated at times of 3, 5, and 10 min, and the FE-SEM results obtained from this stage showed that after 10 min, Cu2S nanoparticles have the smallest size. Also, the effects of the prepared Cu2S nanoparticles on the thermal conductivity, density, and viscosity of engine oil were investigated. The results obtained from this research show that the increase in thermal conductivity compared to the base oil indicates that these nanoparticles improve the heat transfer ability and operation of engine oil in harsher temperature conditions. https://jpst.irost.ir/article_1709.html The presented work is innovative in proposing a novel equation for the velocity of constituent particles in relativistic localized states, derived from a unique synthesis of quantum field theory, memory models, and harmonic-oscillator dynamics. This approach offers a new way to model the internal dynamics of hadronic systems, with potential applications in nuclear physics and exotic atoms. Its primary strength lies in integrating disparate theoretical frameworks to describe complex quantum phenomena effectively. We introduce a significant physical equation for calculating the velocity of constituent particles in a localized state, derived from quantum field theory, the relativistic behavior of interactions, and a memory model for moving mass. This equation is obtained from the ratio of the relativistic mass to the rest mass of the constituent particles, together with Boltzmann’s constitutive equations for a quantum harmonic-oscillator system that incorporates the Kelvin–Voigt memory model and the features of quantum field theory characteristic of the strong interaction within a hadronic localized state. Initially, we determine the relativistic masses of the constituent particles in pionic-atom localized states (bound states) by solving a modified Schrödinger equation in a symplectic space constructed from two intertwined subspaces generated by the creation and annihilation operators. We then employ the Kelvin-Voigt memory model equation to determine the velocities of the particles in the relativistic regime within the framework of the strong interaction among hadrons. The theoretical predictions for the pionic atom are in good agreement with current experimental data. https://jpst.irost.ir/article_1719.html A composite nanofiltration membrane was successfully fabricated via a single-step electrospraying process for the efficient removal of bentazone from contaminated water. Key electrospraying parameters—polymer concentration, solution flow rate, and applied electric field strength—were systematically optimized using the Taguchi design of experiments, which identified polymer concentration as the most influential factor governing membrane performance. The optimum fabrication conditions were determined to be a 5 wt% polymer concentration, a 2.2 mL.h-1 flow rate, and a 0.66 kV.cm-1 electric field strength. The fabricated membranes were characterized using scanning electron microscopy, nitrogen adsorption–desorption, water contact angle, and surface profilometry. Membrane performance was evaluated using a 200 mg.L-1 bentazone feed solution in a vacuum-assisted dead-end filtration system operated at a transmembrane pressure of 10 psi. Under these optimal conditions, the membrane exhibited a pure water flux of 34.7 L.m-2.h-1. During bentazone filtration, the flux decreased to 19.75 L.m-2.h-1, while achieving an excellent bentazone rejection of 96.2 ± 1.44 %. These findings confirm that optimizing electrospraying parameters, particularly polymer concentration, is critical for developing high-performance composite nanofiltration membranes. Overall, the proposed single-step electrospraying method offers a simple, highly controllable, and practical alternative to conventional approaches for fabricating composite nanofiltration membranes.