Papers by Keyword: Temperature Effect

Abstract: The sugar palm flour industry generates substantial solid waste, contributing to environmental pollution. The utilization of waste pellets as raw material for pyrolysis for bio-oil production has not been widely studied. Pelletization aids handling and improves pyrolysis efficiency through uniform size and density. This study investigated the effect of pyrolysis temperatures of the pellets on the yield and quality of the produced bio-oils. Pyrolysis was carried out non-isothermally with a heating rate of 40°C/min, starting at room temperature and continuing until the final temperature was reached, which was varied at 300°C, 400°C, and 500°C in an N₂ atmosphere. The condensed vapor was then collected in a closed container and subjected to several analyses, including yield, viscosity, density, pH, calorific value, and chemical composition. Results show that the optimal temperature was 400°C, at which the bio-oil exhibited the highest yield (43.8% wt), the lowest viscosity (2.05 cSt), the highest density (1.138 g/mL), and a sufficient calorific value (1.0 kcal/g on a wet basis). Gas Chromatography-Mass Spectrometry analysis revealed that the acidic compounds (phenolics and carboxylic acids) in bio-oil increased with increasing pyrolysis temperature. Higher temperatures increase bio-oil yield by breaking down biomass components, such as lignin. However, excessive heat causes the thermal cracking of the produced organic vapors, thereby reducing yield and increasing acidic compounds. Our novel study presents new opportunities for utilizing pelletized biomass waste-derived bio-oil as a biofuel. However, improving bio-oil quality—particularly by reducing acidity and increasing calorific value—may require upgrading techniques such as catalytic pyrolysis, which should be explored in future research.

Abstract: This contribution, based on literature review, presents a general overview of properties and applications of transparent conductive oxides, TCO. The requested properties of TCO are a high conductivity associated to high transparency in a wide wavelength range. The relation between the techniques used for deposition or growing TCO and the possibility of their doping with appropriate dopant and concentration were discussed relatively to their applications and properties. Thus, we present in this part, the various possible techniques for growing TCO and discuss the effect of the temperature on the functional properties. This self-consistent presentation is also considered to introduce a better understanding of the expected requirements for TCO integrated as transparent electrodes in photovoltaic cells and modules. These developments of TCO for photovoltaic applications will be presented in a second publication.

Abstract: The thermal management processes for PhotoVoltaic (PV) cooling applications, increase PV systems’ overall efficiency and yield to a maximized power generation. Accordingly, this paper investigates recent PV thermal management methods, which involve the use of Phase Change Material (PCM) under the back of PV modules. Compared to other cooling methods (such as air and water based methods) PCM based techniques show less need for maintenance, are environment-friendly, and have a longer life cycle. Since PCM are diverse in nature, and many methods exist to guide their selection procedure, this paper begins by revealing different types of PCM, which are found to be as Organic, Inorganic, Eutectic and Commercial PCM, with the characteristics of each. After acknowledging different PCM natures, a selection process is established based on either the melting temperature, latent heat, or thermal conductivity of PCM. Results have shown that Commercial PCM are the best option followed by Organic PCM, due to their improved chemical aspects when compared with Inorganic and Eutectic PCM. Concerning PCM selection criteria, the easiest yet sufficient process is based on the melting temperature method, due to the simplified calculations when compared to other thermic quantities. At the end, future work recommendations are declared, related to PCM lifecycle assessment and cooling/heating cycles effects on PV entropy.

Abstract: Reinforced plastics are widely used in various fields of technology for a wide variety of structures. They provide high strength at low density, resistance to aggressive media, low material intensity of production, high manufacturability, the ability to regulate heat and electrical conductivity over a wide range, the ability to repair without the use of special equipment, they perform in a broad range of temperatures and stresses. Reinforced polymer composites with the use of fiberglass-based textile materials as reinforcement are the most used due to their availability, low cost and high strength properties. This scientific paper presents the results of specimen tests with a substrate of various types of steel, adhesive compositions as bonding material, and fiberglass as reinforcing material. The influence of the properties of the substrate and coating materials, and the ratio of their thicknesses on the theoretical strength of the composite element was investigated. The results obtained will make it possible to clarify the design schemes and dependencies in the design and repair of structural elements with reinforced polymer coatings.

Abstract: Presented here are the results of assessing the effect of elevated temperature on the strength characteristics of reinforced concrete structures during operation. Described here are the features of the technical inspection of structures subjected to temperature effects (after a fire). The strength class of reinforced concrete structures was determined before temperature exposure (in places that were not exposed to fire) and after in the course of the study. Presented are the results of measuring the strength of concrete by the direct method of pulling off with spalling, as well as the results of verification calculations of reinforced concrete structures exposed to temperature effects. When performing verification calculations, the percentage of reduction in the bearing capacity of structures was established. Based on the results of the study, the percentage ratio of the decrease in the strength of prefabricated reinforced concrete structures after a fire during the operation of the facility was established.

Abstract: The mechanical properties and deformation mechanism of nickel nanowire of dimension 100 Å (x-axis) × 1000 Å (y-axis) × 100 Å (z-axis) containing a single linear surface defect is studied at different temperatures using molecular dynamics simulations. The defect is created by deleting a row of atoms on the surface and is inclined at 25° to the loading axis. The tensile test is carried out at 0.01 K, 10 K, 100 K and 300 K temperature and 10⁸ s^-1strain rate. To determine the effect of temperature on the stress-strain curves, fracture and failure mechanism, a thorough investigation has taken place. Maximum strength of 21.26 GPa is observed for NW deformed at 0.01 K temperature and the strength decreased with increase in temperature. Through slip lines, the deformation relief pattern taken place by developing the extrusion areas along with intrusion over the surface defect area in all NWs deformed at respective temperatures. Further it is observed that fracture strains decrease with increase in temperature. After yielding, stacking faults associated with dislocations are generated by slip on all four {111} planes. Different type of dislocations with both intrinsic and extrinsic stacking faults are noticed. Out of all dislocation densities, Shockley partial dislocation densities has recorded a maximum value.

Abstract: High-entropic magneto-plum-bite structured crystal phases were theoretically calculated and then prepared by solid state synthesis. The compositions and formation conditions for by-product, such as spinel structured multicomponent crystals, that had not been previously described in literature, were analyzed. The list of elements which can be the main components of such phases was defined. Important conclusions about the conditions for growing high-entropy crystals from melts were made. Particularly, it was shown that the obligatoriness for additional oxidation of the melt should be taken into account (relative to the level that the composition of the melt itself and the process atmosphere can provide).

Abstract: High-temperature wear and friction properties of ZE41 alloy were evaluated using a pin on disc tribometer. The microstructure of the alloy has the equiaxed grains of 72±20µm decorated with the rare earth rich precipitates. Result shows that wear rate decreases upto 100°C and then increases until 250°C for all the loading conditions. The wear mechanism study revealed that the underlying thin oxide tribolayer minimizes the wear rate upto 100°C. Above 100°C, thickening of oxide layer due to enhanced oxidation rate results in breakage of the layer. Further, the increase of temperature softens the alloy which deforms and fractures in the subsurface at low critical load resulting in more delamination wear. The combined effects of oxidation and delamination wear are accentuated with the increase of load and temperature resulting in the increase of the wear rate. Comparing the influence of load and temperature on the wear rate, contact load is more.

Abstract: The article deals with the method of obtaining a hard chromium coating with using abrasive tool. The influence of the pressing force of the abrasive tool, the rotation speed of the part, the temperature of the electrolyte on the results of galvanomechanical chromium plating of rotating cylindrical parts has been studied. A special abrasive tool has been developed for use in the galvanic mechanical coating of metal parts. The tool is made on a polymer bond. The effect of the electrolyte temperature on the quality of the precipitated chromium is revealed.

Abstract: In this study, Co_0,7Zn_1,3W powders were synthesized and investigated at the microwave region. The solid-state reaction method and self-propagating high-temperature synthesis were used to production of the two kinds of hexaferrite powders. The high-frequency magnetic properties under temperature effect have been studied. It is show, that there is a nonlinear dependence on temperature within the 0 – +40 °C temperature range.