Original Article
Radar/thermodynamics/heat transfer/fuel and combustion/energy/...
Mohammad Pourjafargholi; alireza gholami; Mohammadreza Karimi
Volume 3, Issue 3 , December 2024, Pages 1-26
Abstract
In this study, has been investigated the effects of key parameters, including coolant flow velocity and temperature, heat flux, and fin angle, on heat transfer performance. For this purpose, a concave parabolic fin has been used with angles of 0, 45, and 90 degrees relative to the coolant flow (air), ...
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In this study, has been investigated the effects of key parameters, including coolant flow velocity and temperature, heat flux, and fin angle, on heat transfer performance. For this purpose, a concave parabolic fin has been used with angles of 0, 45, and 90 degrees relative to the coolant flow (air), flow velocity (between 1 and 2.5 m/s), and heat flux of 18.5 and 4.6 kW/m2. Due to its high thermal conductivity, the fin material has been selected aluminum. Results reveal that the parabolic fin's sharp-tip and curvature not only reduce its weight and volume compared to a triangular fin but also improve flow uniformity and thermal contact area. This leads to reduced pressure drop and thermal stresses, ultimately enhancing fin durability. The parabolic fin’s sharp end further minimizes vortex formation and variations in the heat transfer coefficient, and as flow velocity increases, the average heat transfer coefficient rises. Moreover, the analysis shows that changes in the angle between the fluid flow and fin alignment have minimal impact on fin efficiency, with pressure drop primarily influenced by flow velocity. The lowest pressure drop occurs at a flow angle of zero degrees. Additional, findings indicate that while an increase in flow velocity substantially raises pressure drop, changes in fin angle and heat flux have less pronounced effects. At zero-degree flow alignment, the minimal cross-sectional resistance of the fin results in the lowest observed pressure drop.
Original Article
Electromagnetism, electronics and cyber-electromagnetism (disturbance in waves, jamming, strong microwave waves, etc.)
R. Razavi; Mohammad Reza Kardgar; Ali Shekari; Morteza Ramezani
Volume 3, Issue 3 , December 2024, Pages 27-40
Abstract
The radar receiver protector is one of the important components in the radar system. It prevents the receiver from noise and powerful Electromagnetic wave. In this paper, the simulations are done for different structures of the radar receiver protector using COMSOL software in the X-band frequency.The ...
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The radar receiver protector is one of the important components in the radar system. It prevents the receiver from noise and powerful Electromagnetic wave. In this paper, the simulations are done for different structures of the radar receiver protector using COMSOL software in the X-band frequency.The simulation selected structure is based on the WR90 waveguide structure. In this simulation, parameters such as reflection and transmission coefficients, as well as the maximum field intensity created within different radar receiver protector structures, have been investigated. The studied structures include iris-diaphragms-pairs, posts-and-diaphragms, truncated-cones-and-diaphragms, Dumbell-pointed-post-tunable, Dumbell-pointed-post, and Dumbell structures.The simulation results show that the internal structure of the waveguide has an important parameter on the filtration performance, the frequency selection and intensity modes created on the tips of the electrodes. Dumbell-pointed-posts-tunable among the investigated structures due to the frequency modes and high intensity of the electric field at the tip of the electrodes, it is superior to other structures.
Original Article
Passive defense (detection, decontamination and protection and safety - chemical, biological and nuclear, etc.)
Hosain Tavallali; Raziyeh Karimi Nejad Ghasroddashti; Abolfath Parhami; Vahid Tavallali
Volume 3, Issue 3 , December 2024, Pages 41-62
Abstract
Military training activities are a serious concern for defense organizations around the world. These activities, targeting underground soils, are environmental pollutants. On the other hand, providing suitable drinking water for the field forces is only one of the engineering department’s numerous ...
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Military training activities are a serious concern for defense organizations around the world. These activities, targeting underground soils, are environmental pollutants. On the other hand, providing suitable drinking water for the field forces is only one of the engineering department’s numerous and diverse military duties. Therefore, it is necessary to investigate the various pollutants in the water that the soldiers need to explore.In this research, a new type of available, fast, highly sensitive, and selective colorimetric method for the determination of sulfide ions using a complex based on a metal mixture of ligands is presented. In this study, the Zn2+ complex with Eriochrome Black T dye (EBT) and the complex formed with erythrosine dye (ERS) was proposed (EBT-Zn2+-ERS) as a sulfide anion chemosensor for the first time. The linear range of sulfide is 0.20-92.85 µmol/L and its correlation coefficient is 0.9917. Also, the method's detection limit was 0.04 μmol/L, and the relative deviation in two concentrations of 0.38 and 0.69 μmol/L was 1.64 and 0.84%, respectively. The presented method was successfully used the rapidly determine of sulfide ions in samples of drinking water from military barracks, mineral water, and Maharlo Lake water.This method is less expensive than previous methods, and is recommended for various fields in defense environments.
Original Article
IT and cyber warfare (encryption and data security, penetration and disruption in information networks, radars, dealing with hackers, etc.)
Eynollah Khanjari; Amir Hossein Shokouhi
Volume 3, Issue 3 , December 2024, Pages 65-89
Abstract
In a world where food and pharmaceutical security are vital components of passive defense, the management and preservation of supply chains for environmentally sensitive pharmaceuticals are crucial. Governments prioritize pharmaceutical logistics to ensure the availability of essential drugs, particularly ...
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In a world where food and pharmaceutical security are vital components of passive defense, the management and preservation of supply chains for environmentally sensitive pharmaceuticals are crucial. Governments prioritize pharmaceutical logistics to ensure the availability of essential drugs, particularly during crises and sanctions. In countries like Iran, the high sensitivity of biological materials and their vulnerability to heat necessitate continuous monitoring of drug distribution systems. Delays due to traffic, transportation accidents, and human error can severely disrupt the supply chain, leading to drug trafficking, medication loss, and public health risks.This paper addresses a significant challenge in Iran's pharmaceutical logistics: managing the massive volume of spatiotemporal data from refrigerated drug distribution vehicles. To optimize the segmentation of distribution fleet routes, the paper introduces a method named SEGA, inspired by the genetic algorithm, offering an innovative approach to saving time and enhancing performance. This spatiotemporal data, including refrigerator temperature, external temperature, vehicle speed, and location, is critical for maintaining the safety and quality of pharmaceuticals. However, the continuous, real-time transmission of this data can lead to database overflow, necessitating efficient data management and summarization techniques.Experiments and simulations demonstrate that the SEGA method significantly improves the performance of the genetic algorithm, effectively segmenting and summarizing the data. The results indicate that this approach can enhance the system's speed and efficiency by up to 92%, providing a robust solution for optimizing pharmaceutical logistics in challenging environments.
Original Article
Radar/thermodynamics/heat transfer/fuel and combustion/energy/...
Gholamreza Faghani
Volume 3, Issue 3 , December 2024
Abstract
Film cooling is one of the most important parts of gas turbines and turbojet engines. In this paper, three dimensional cooling performance on a flat plate is calculated with a 3D finite-volume method and the realizable k-ε turbulence model which is the improved of standard k-ε turbulence ...
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Film cooling is one of the most important parts of gas turbines and turbojet engines. In this paper, three dimensional cooling performance on a flat plate is calculated with a 3D finite-volume method and the realizable k-ε turbulence model which is the improved of standard k-ε turbulence model. In this investigation, to obtain the best film cooling effectiveness case, the effects of density ratio (by air and CO2 as coolant) (DR), blowing ratio (M), the effect of changing the injection angle of coolant fluid (compound angle) and the main stream turbulence intensity on film cooling effectiveness are studied. For validation, the film cooling effectiveness for numerical data has been compared with the experimental data and these comparisons have been shown a good agreement between experimental and numerical data. Results showed that by increasing blowing ratio and the main stream turbulence intensity, the film cooling effectiveness decreases. Also, by increasing the injection angle of coolant fluid, the film cooling effectiveness increases. As a result, by increasing the injection angle of coolant fluid in low blowing ratios and main stream turbulence intensity, the film cooling effectiveness can increase considerable.
