Stirling engines represent a category of external heat transfer engines that demonstrate versatility by harnessing various heat sources, including solar energy, bio-mass, conventional fuel, and nuclear power. Achieving high thermal efficiency in power production has been a paramount concern driving researchers across the globe to focus on developing Stirling engines. In this particular research endeavor, a gamma type double-piston Stirling engine has been carefully selected for detailed analysis. To gain deeper insights into the engine's behavior, a polytropic model is employed in the investigation. The outcomes derived from the polytropic analysis are subsequently compared with classical adiabatic analysis. Remarkably, the polytropic approach significantly outperforms the classical adiabatic analysis in enhancing the overall performance of the Stirling engine. The results holds significant promise for advancing the efficiency and practical application of Stirling engines, reinforcing their position as a prominent contender in the pursuit of sustainable and highly efficient power generation technologies.

Backward extrusion is a suitable method for forming thin-walled cup-shaped details. However, the deformation force is very large, making it difficult to choose equipment and ensure the durability of the die. The continuous extrusion method is improved from the traditional backward extrusion method to overcome the main disadvantages in the deformation process. The die structure in continuous extrusion is improved, including three main parts: fixed punch, primary punch and die. The use of a smaller size original workpiece that is deformed in the fixed punch and flows into the die cavity is the cause of the significant reduction in the deformation force. The result obtained is that the deform of the workpiece is uniform and 200% larger according to the product height, and the deformation force is reduced by less than ¼ compared to the traditional backward extrusion method. Therefore, continuous extrusion method is highly applicable in the production of products in industry and national defense.

Wearable antennas for biotelemetry wireless communication are specialized antennas that are designed to be worn on or integrated into the body in order to enable wireless communication between devices such as medical implants, heart monitors, and other biotelemetry devices. Antennas of this type are typically very small and must be capable of working effectively in the presence of the human body. Wearable antennas for biotelemetry wireless communication can be made from a variety of materials including metals, plastics and textile materials. They are designed to work in different wireless communication frequencies such as UHF, ISM and Medical implant communication service (MICS) bands. These antennas are crucial for wireless communication of vital signs and other medical data which are collected by the biotelemetry devices and transmit them wirelessly to a remote location for monitoring and analysis.

Among various configurations for fiber-optic distributed strain and temperature sensors, Brillouin optical correlation-domain reflectometry (BOCDR) is known to have high spatial resolution, random accessibility to measurement points, and single-end accessibility. The spatial resolution in BOCDR relies on accurately determining the modulation amplitude of the light, which is inversely proportional to the product of the modulation amplitude and frequency. Existing approaches for modulation amplitude measurement in BOCDR involved observing the modulated light spectrum using an optical spectrum analyzer (OSA) or employing a separate heterodyne detection system with an electrical spectrum analyzer (ESA). However, OSA-based methods suffer from limitations in frequency resolution, high costs, and bulky size, while using a separate heterodyne detection system requires modifications to the BOCDR setup, reducing convenience. In this study, we present a novel method for measuring modulation amplitude in BOCDR without modifying the experimental setup. Our approach utilizes the spectral width of noise caused by Rayleigh scattering, enabling modulation amplitude measurement without length constraints on the sensing fiber. By directly observing the Rayleigh-noise components using the existing BOCDR setup and an ESA, our method provides high-frequency resolution and straightforward implementation. This significantly enhances the convenience of modulation amplitude measurement, facilitating accurate spatial resolution evaluation in BOCDR.

The primary goal of this research is to enhance the design of an injection mold through the strategic repositioning of cooling channels. This optimization is intended to minimize ejection time and enhance temperature uniformity within the mold. The ANSYS Finite Element Method (FEM) software was employed to perform two-dimensional (2D) transient thermal simulations, while the MATLAB software was utilized for optimization reasons. The effectiveness of the method in maximizing the design of conformal cooling channels (CCCs) in injection molds was determined. The objective function value of the optimized model exhibits significant improvement when compared to the baseline model. The usefulness of enhancing the configuration of channels within an injection machine mold has been established through the utilization of a comprehensive strategy that involves parameterization, modeling, and optimization. The methodology demonstrates the potential for generalizability. Hence, it finds extensive application in several industrial sectors, particularly in the domain of injection molding machines, with the primary objective of augmenting the overall quality of the manufactured component.

The Inductively Coupled Plasma Mass Spectrometry (ICP-MS) lies among the most dominant techniques for rapid spectroscopic multi-element analysis as a result of a set of attributes such as low detection limits (often parts per billion or trillion), a wide linear dynamic range and high precision. This work offers a comprehensive examination of ICP-MS as a higher level analytical method compared to Atomic Absorption Spectrometry (AAS) and X-ray Fluorescence (XRF). Comparisons between ICP-MS and AAS were made with the determination of the concentration of trace elements in the same solid alternative fuel samples, while comparisons between ICP-MS and XRF were made by the determination of the concentration of major elements in the same Solid Recovered Fuels, resulting in the superiority of the method. While acknowledging that the initial cost and complexity of operation may deter some from adopting ICP-MS, the study asserts that the advantages of enhanced precision, sensitivity, and speed of analysis validate the investment. Hence, ICP-MS is an extremely important laboratory tool used in modern physics and chemistry and has a wide range of applications: biological materials, high purity reagents and metals, atomic nuclear materials, geological samples and food.

In the era of digital communication and social networking, the authenticity and integrity of personal social network profiles have become crucial for establishing trust and ensuring secure interactions. Existing methods often suffer from vulnerabilities like password theft, identity impersonation, and data breaches. To overcome these challenges, the paper introduces a new steganography method as a robust solution, leveraging the concept of hiding information within seemingly innocent digital cover image. The proposed methodology involves embedding unique and imperceptible authentication data within profile images. This scheme is developed using shell matrix and absolute-moment block-truncation coding (AMBTC) compression. The shell matrix is used for concealing the private information and AMBTC compression is applied to compress large data files into smaller ones, which can speed up network transmission of compressed code. By exploiting the redundancy in image data, the authentication data is embedded in a manner that is indistinguishable to human observers. To evaluate the effectiveness of the proposed approach, extensive experiments were conducted using real-world social network profiles. The results demonstrate the ability of the proposed technique to successfully embed and extract authentication data while preserving the visual quality of the profile images.

Additive manufacturing allows the creation of geometries otherwise impossible to achieve through traditional technologies in mechanical components. These geometries can be obtained using algorithms to optimize the mass distribution. Topology Optimization algorithms are one of the tools most applied in design for additive manufacturing and lightweight engineering. These optimization techniques require Finite Element Method tools to evaluate and compare the mechanical behavior of different geometrical solutions. The optimization results are closely related to boundary conditions, objectives, and constraints. Therefore, one of the issues is the necessity to evaluate different parameter settings to improve the result in terms of lightweight, strength, and easy printability. This article shows a working method to use topological optimization for lightening a connecting rod. The resultant model is optimized considering Additive Manufacturing.

This study focuses on investigating the phase transitions in two materials, Cu2ZnSnS4 (CZTS) and CuZnGeS4 (CZGS), which are important for understanding their structural and functional properties. The temperature and pressure-induced tetragonal-orthorhombic phase transitions in these materials are analyzed using density functional theory (DFT) and the quasi-harmonic Debye model. The research aims to examine the changes in the material's structure and the associated thermodynamic properties during these phase transitions. The results reveal that both compounds exhibit a negative value of ΔHmix, indicating the release of energy during the mixing process, which suggests an exothermic nature. Our DFT calculations at zero temperature and pressure, demonstrate that the Stannite structure represents the ground state configuration of the Cu2ZnSnS4 system (with xGe = 0%), compared to the Wurtzite-Stannite structure. The calculations also show that the difference in enthalpies of formation (∆H) between the Stannite and Wurtzite-Stannite phases for CZTS is estimated to be 8.884meV per atom. Regarding Cu2ZnGeS4, the Wurtzite-Stannite structure is found to be the most stable, closely followed by the Stannite structure, with enthalpies of formation of -4,833eV.atom-1 and -4,804eV.atom-1, respectively. Notably, there are no definitive reports on enthalpy studies for the Cu2ZnGeS4 system in the existing literature. Furthermore, the DFT studies indicate that the energy difference between the Stannite and Wurtzite-Stannite phases in CZTS is smaller than that in CZGS, amounting to 29.195eV per atom. The temperature has minimal influence on the thermodynamic Gibbs energy of these quinary alloys. This suggests that the ability of these alloys to undergo changes in their crystal structure is not strongly dependent on thermal energy. While maintaining a constant temperature at 0K, it has been observed that the effect of pressure on the Gibbs energy for both compounds is relatively small. However, it is worth noting that at higher pressures (>45 GPa), a phase transition from Stannite (St) to Wurtzite-Stannite (WSt) occurs for CZTS, and from WSt to St for CZGS. Understanding the behavior of these materials under different conditions can contribute to the development of improved performance and stability of devices based on CZTS and CZGS.

Voltammetry has been used in many industries and has been a popular method of food analysis in recent years. Its high sensitivity, rapid analysis, availability in the wide variety of concentrations and temperature posed positive potential in the wine industry. With standardized methods of food analysis bulky and time-consuming for the fast market, the main purpose of this study is to gain an understanding of the possible benefits of voltammetry can provide to the wine industry. The review paper focused its discussion on the different voltammetric methods, parametric conditions and electrochemical behavior of detected compounds wherein wine was the main substance of origin. Particularly, the limit of detection (LOD), initial voltage peak, pH levels, working electrodes, and their respective reagents was taken into account to determine the applicable methods that can be utilized in the wine industry. The study could served as a point of reference for future research into the aforementioned topic.