Papers by Keyword: Temperature

Abstract: An exact measurement of the disc brakes car temperature present difficulties, because the higher thermal stress is produced on the shiny metallic surface, which are in movement and in sliding contact with the brake pads. If an infrared camera is used for the thermal evaluating of the disc brakes, an important factor that must be considered is the reflected temperature. The aim of this research is to study the modification of the reflected temperature in correlation with the disk brake temperature and to establish a relationship for the estimation of this variation.

Abstract: Small diesel engines with direct injection air cooled a big problem is heat dissipation. Based on bench made ​​with a 295 cc diesel engine with direct injection, air cooled, I set the heat flows through the cylinder head, piston and cylinder. These data are needed to study the possibility of operating at maximum power, knowing that mechanical stresses of thermal origin are the most dangerous. The data obtained in this work will be used in the analysis of temperature and stress fields.

Abstract: This paper presents a study regarding the emissions caused by the running of a cold engine and studies the influence of the four-stroke gasoline engine’s temperature on CO₂, CO, HC emissions. Experimental research has been done for three light vehicles equipped with a 1390 cm³ Renault spark ignition engines. Several test have been made under different temperature conditions by using a BEA Emission Analyser - Bosch. The experimental data have shown that the engine’s temperature has an influence on CO₂, CO, HC emissions. The results show that the highest pollutants values are recorded for low exhaust gases temperature and for cold engine’s running regime.

Abstract: A turning knife contacts a work piece during turning. Due to friction, heat is produced proportionally to the turning speed. The resulting temperature influences the quality of the machined surface and wear of the knife. Thus, new machine tools must be developed that minimize the production of unwanted heat. To accomplish this task, a new experimental knife was prepared with thermocouples both built into it and welded to its surface. The measurement process was supplemented by thermovision. Heat flux and surface temperatures were computed from subsurface data using a one-dimensional inverse relationship. The detailed temperature distribution on the surface of the turning knife was determined using a combination of these methods.

Abstract: This paper presents an application of the probabilistic analysis of structural resistance of the bubble tower structure of a VVER 440/213. The evaluation is based on an extension of the smeared crack model developed on base of Kupfer's bidimensional failure criterion, rotated crack, CEB-FIP model of failure energy and implemented into the ANSYS system. The non-linear analysis was considered for the median values of the input data and the probabilistic analysis models the uncertainties of loads, material resistance and other modeling issues.

Abstract: The purpose of this study was to prepare biphasic granules containing gypsum and carbonated apatite at low temperatures. The biphasic granules were prepared using dissolution-precipitation technique at three different temperatures 30°C, 40°C and 50°C. Characterization of the biphasic granules was determined by multiple analytical methods such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red (FTIR), and CHN Analysis. The obtained granules were determined by XRD as biphasic granules containing bone apatite and gypsum. The cross-section of biphasic granules was observed by SEM. The formed bone apatite was identified as B-Type carbonated apatite using FTIR The carbonate content in biphasic granules fabricated at 30°C, 40°C and 50°C were recorded by CHN analysis as 5.0 wt%, 6.1 wt% and 6.25 wt%, respectively.

Abstract: The use of fly ash as an alternative material for cement substitute in concrete mix already a common practice nowadays. However, as a waste material, fly ash varies in quality and condition, as shown by variation of its fineness, specific gravity, Loss on Ignition (LOI) and also on its chemical composition. By measuring the acidity (pH) of the fly ash in water solution, percentage of mass retained on 45 μm sieve, and superplasticizer demand of the fly ash, we can develop a quick estimation of the quality of fly ash. This study aims to investigate a quick method to estimate the quality of fly ash by measuring the physical and chemical pointers, as indicator for its properties and the effect on the setting time and compressive strength of mortar. Fly ash content was varied from 0-70% of the total mass of cementitious materials to make HVFA mortar. Fly ashes were obtained from four power plants in Indonesia. Tests conducted were material characterization, setting time, temperature rise, and compressive strength of mortar at different ages. Different fly ash quality can be shown by the fast pointers; namely pH, superplasticizer demand and % retained on 45 μm sieve. Setting time and strength development were affected by the different properties of fly ash.

Abstract: Fiber-optic sensors are mostly used for in situ measurements of diverse chemical composition of industrial surfactants employed in industry as detergents, emulsifying and dispersing agents, coatings, and pharmaceutical adjuvants. These optical sensors are often used in wet chemical environments in which the temperature can be high.The purpose of this work is to study the mechanical behaviour of optical fibers in contact with CetylTrimethylAmmonium Chloride in aqueous solution (CTAC) at different immersion durations and different temperatures.Optical fibers were submitted to dynamic bending test under different velocities.Result analysis demonstrates that immersion in CTAC drastically decreases the fiber strength particularly when immersed for long aging periods at high temperatures.

Abstract: The cooling systems on machine tools are particularly important; these have a positive influence on the cutting operation and the quality of machined surface. A particular importance represent finding an optimal correlation between the lubricant and coolant used, the material to be processed, processing method and the cutting regime. A high temperature in the working area over a certain value allowable can be harmful in terms of both the resulted surface quality and repercussions on the life of the cutting tool. The parameters of the cooling-lubricating fluid flow can be influenced by the nature of the fluid or fluids, or the nozzle geometry used, which generally has a convergent-divergent geometry in order to achieve a better dispersion of the coolant/lubricant on the area to be machined.

Abstract: Processing metallic materials by cutting using good electricity conductor cutting edges it appears an electrical current due mainly to the temperature in the cutting zone. Analyzing of the electrical current the information about the unfolding mode of the cutting process can be obtained. The cutting electrical current can be used in several applications: the estimation of the temperature in the cutting zone, the estimation of the cutting forces, the identification of the wear state of the cutting edge etc. The first researches were started in Russia and they were based on the utilization of the cutting electrical current to measure the temperature in the cutting zone. Afterwards, other applications were identified in the literature and the researches were extended in other countries like India, Japan, USA, Brazil, France, Bangladesh and Romania. This paper presents a review of the researches about the electrical current which appears at cutting process.