Papers by Keyword: Comparison

Abstract: With the development of radar-detecting technology, stealth technology is important for military weapons and equipment. As a typical structural stealth material, wave absorption honeycomb has a wide range of application prospects and research value. The light and high absorption wave absorption honeycomb that uses electromagnetic-modified aramid paper as a raw material has the advantages of light density and good absorption performance, making it suitable for the lightweight requirements of the new equipment. Here, the electromagnetic-modified aramid was the raw material of the honeycomb. The hexagon honeycomb and overexpanded honeycomb were prepared. We also analyzed the influence of the cell shapes on the honeycomb properties. The results showed that cell shapes had little effect on the plane compression and shear performance of L. The overexpanded honeycomb’s L and W shear performance was basically the same. The hexagon and overexpanded honeycomb have good electromagnetic wave absorption performance in 1 GHz ~ 18 GHz frequency band.

Abstract: Human security remains a topical issue, especially on the country borders where temporary houses are often used. Optimally, people should be provided with ordinary, habitable, easy-to-build, possibly portable buildings and ballistically protected. However, there is a lack of studies addressing ballistic building materials for the walls. In the scope of this study, ten ballistic materials: sand walls, concrete, steel plates, ceramic, glass fibreboards, wood (plywood, cross-laminated timber), ultra-high molecular weight polyethylene (UHMWPE) boards, aramid boards, carbon fibre boards, and gypsum plasterboard are reviewed, and their wall constructions are compared. This paper aimed to analyse bulletproof materials and to nominate the best bulletproof walls according to three required aspects - price, thermal transmittance, and weight. This is a review article that could help stakeholders to choose the appropriate ballistic material for high-risk applications.

Abstract: In this work, the H3TRB performance of power modules with SiC MOSFET chips is investigated and compared to their silicon counterparts with similar electrical ratings. For this purpose, SiC MOSFETs and silicon IGBT chips are packaged in the same housing and with the same packaging technology and an H3TRB test is performed on both types of test devices. The results show that while both types exhibit an excellent H3TRB performance, the SiC MOSFETs had a significantly longer time to failure but also a wider failure distribution. Hence, the investigations presented in this paper confirm that properly designed SiC devices feature an equal or even better ruggedness against electro-chemical stress than standard silicon devics and are equally suitable for applications, which require operation in harsh environments.

Abstract: Hydrodistillation (HD) is a traditional technique used in most extraction processes. On the other hand, microwave-assisted hydrogen distillation (MAHD), an advanced method using microwaves in the extraction process, has recently emerged. The chemical ingredients of essential oils obtained from pomelo (Citrus grandis L.) peels obtained by MAHD and by hydrodistillation (HD) were analyzed and compared gas chromatography-mass spectrometry (GC/MS). The results show that there is no significant difference between the two methods in terms of extraction efficiency, at around 4.45 to 4.7%. The main components of essential oils were Limonene, α-pinene, β-Myrcene and Sabinene. The content of those compounds showed no clear quantitative and qualitative difference between HD and MAHD. Experimental results show that the MAHD method provides a good alternative to extracting essential oils from grapefruit, saving time, operating costs and achieving more optimal levels. Keywords: Comparison, Pomelo (Citrus grandis L.), Essential oil, Hydrodistillation, Microwave assist hydrodistillation,

Abstract: The transition to a highly productive and environmentally friendly agricultural sector, the development and implementation of systems for the rational use of mineral fertilizers for obtaining safe and high-quality, including functional, food products is one of the main tasks allocated by the President of the Russian Federation V. V. Putin. Due to this decree, the theory of mineral nutrition has received rapid development in recent decades within scientific and technological progress in the field of analytical chemistry and physics, molecular biology, and genetics. Information on various physiological and biochemical functions of plant nutrients has been obtained, and the regularities of the distribution of elements in various parts of plants and fruits (berries) have been also generalized. The main forms of nutrients in the soil and the factors determining the bioavailability of macro and micronutrients have been identified. The aim of this research paper is to produce a biodegradable fertilizer where Azofoska Universal (N16: P16: K16) was uniformly coated within layer size by water-soluble biopolymer through continuous flow reactor V-star. The obtained samples were further tested and compared to well-known American analog slow-released fertilizer TAGROW on berry plants under greenhouse conditions within, berry root plant volume, stress resistance of plants, yield, the resulting fruits were studied for sugar levels using an RHB-32ATC refractometer. Moreover, infrared spectroscopy data for obtained biopolymer coated Azafoska Universal is illustrated in this research.

Abstract: Removal of heat generation is an important characteristic needs to be considered in electromechanical and electronic devices which improve the stability and feasibility of system. Despite numerous cooling methods, heat pipes are recent updating in research line. Heat pipes are one of the super conducting medium of heat energy and it is being used as an equipment to absorb more heat through phase change process of cooling medium circulated in it. It ensures the direct enhancement in heat transfer capacity and characteristics. Nowadays, improvement of the thermal performance in heat pipes getting up with various technologies, especially combination of heat pipe and Nano fluids. It has been experimentally practiced and various results are observed by previous researches that wick structure also a part of reason in improvement. The aim of this research work is to analyze the influence of wick material to improve heat transfer characteristics in heat pipes. In addition, combination of nano coated wick material with heat pipes is comparatively analyzed. From the final observed results it was found that, the best combination of wick material is supporting the better cooling requirements in electronic devices.

Abstract: The article focuses on the research of selected thermoplastic materials processed by the Fused Deposition Modeling (FDM) additive manufacturing method and dimensional accuracy of parts in particular. The selected thermoplastic materials were ABS, PLA and HIPS. The digital model of the object (upper teeth) was obtained by the intraoral 3D scanner of 3Shape TRIOS used in dentistry. Based on the 3D (Three Dimensional) scanned digital model, the manufacturing of the upper teeth was performed on the Zortrax M200 FDM 3D printer. Parameters of the manufactured parts were as follows: Layer thickness 0.09 mm, infill 20% and model orientation 0°. The manufactured parts were digitized by the GOM ATOS Triple Scan optical 3D scanner with the measuring volume of MV 170. The dimensional accuracy of the parts was evaluated in the GOM Inspect software.

Abstract: The comparisons of materials that can be used in gas sensors, as well as an analysis of their advantages and disadvantages for this application are carried out in this review article.

Abstract: This article concerns the integration of planning and scheduling production system. Planning and scheduling are usually treated separately because of their complexity. Scheduling largely depends on the production quantities computed at the production planning level. However, ignoring scheduling constraints in the tactical level leads to inconsistent decisions. So, it is important to integrate planning and scheduling to efficiently manage operations and to determine a realistic production plan for a given sequence of jobs on each machine. In this paper, we present some approaches proposed to solve the problem and we realize a comparison between the two most interesting ones, using the standard solver CPLEX.

Abstract: This study concerns the ground soils of the second runway of the Es-Sénia airport in Oran (Algeria). This airport was built on a very complex hydro geotechnical site when underground cavities, following the dissolution of gypsum soil, were found during the before-construction geologic studies. Several, techniques are used in laboratory (Permeability, triaxial compression tests at various confining pressure, and hydric tests in saturated and unsaturated conditions) and for in situ it’s used the results of SPT and pressure-meter tests. A comparison of parameters of two soils identified in saturated and partially saturated conditions by in situ and laboratory tests was performed in order to respond to questions of the similarity of hydro mechanical properties of two soils as well as their statistical representativeness of the in-situ reality. It is found that, in respect to the studied parameters, laboratory results are statistically significant and reconstituted soils is statistically representative of natural soil reconstitution.