Behavior of Corrosion of a Heat Pipe Cooling Device in a Computer

The aim of this study was to perform life testing and to determine the effect of working time on the corrosion of a heat pipe used for cooling in a computer. The heat pipe was made from a copper tube. The heat pipe consists of evaporator and condenser section. It had a specification similar with the use in ordinary computers, the working fluid being distilled water. When the computer starts, the concentration of the copper solution slightly increases. The greater copper concentration was 0.00062 ppm upon 3000-5000 hours of testing. The surface traces of corrosion rises due to the oxidation of the porous material within the working fluid. The test found that oxygen (O) and carbon (C) are component contents

Micromagnetic model of exchange bias : Effects of structure and AF easy axis dispersion for IrMn/CoFe bilayers

A micromagnetic model of an exchange bias bilayer is used to examine the impact of the physical structure and the easy axis dispersion of the antiferromagnetic (AF) layer on the exchange bias field (HEB) in an IrMn/CoFe system. Because of the different timescales, the magnetization dynamics of the IrMn and CoFe layers are modelled using respectively a kinetic Monte Carlo (kMC) approach and Landau-Lifshitz-Gilbert (LLG) equation. The easy axis dispersion is modelled using a Gaussian distribution. The calculations show that HEBincreases with increasing IrMn thickness and grain size, in agreement with experimental work. Moreover, the model allows the visualization of the switching process at the micromagnetic level to reveal the reversal mechanism. We find that the effect of AF easy axis distribution not only strongly affects the reduction of HEBbut also drives non-coherent behaviour in the reversal mechanism. This confirms that the easy axis distribution is an important factor with strong impact on the magnetic properties and exchange bias field of an exchange bias system

Application of silver nanofluid containing oleic acid surfactant in a thermosyphon economizer

This article reports a recent study on the application of a two-phase closed thermosyphon (TPCT) in a thermosyphon for economizer (TPEC). The TPEC had three sections of equal size; the evaporator, the adiabatic section, and the condenser, of 250 mm × 250 mm × 250 mm (W × L × H). The TPCT was a steel tube of 12.7-mm ID. The filling ratios chosen to study were 30, 50, and 80% with respect to the evaporator length. The volumetric flow rates for the coolant (in the condenser) were 1, 2.5, and 5 l/min. Five working fluids investigated were: water, water-based silver nanofluid with silver concentration 0.5 w/v%, and the nanofluid (NF) mixed with 0.5, 1, and 1.5 w/v% of oleic acid (OA). The operating temperatures were 60, 70, and 80°C. Experimental data showed that the TPEC gave the highest heat flux of about 25 kW/m2 and the highest effectiveness of about 0.3 at a filling ratio of 50%, with the nanofluid containing 1 w/v% of OA. It was further found that the effectiveness of nanofluid and the OA containing nanofluids were superior in effectiveness over water in all experimental conditions came under this study. Moreover, the presence of OA had clearly contributed to raise the effectiveness of the nanofluid

The Sapir Whorf hypothesis and translation or the power and weakness of language

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Design and construction of an oven for drying palm bunch using glycerine as fuel together with using closed-loop oscillating heat-pipe with check valves (CLOHP/CV) heat exchanger for waste heat recovery

138-143This research addresses design and construction of an oven (2 m x 3 m x 2 m) for effectively drying palm bunch using glycerin as a fuel and a closed-loop oscillating heat-pipe with check valves (CLOHP/CV) as a heat exchanger for waste heat recovery. In each experiment, palm bunches (500 kg) were baked in oven with and without CLOHP/CV heat exchanger. CLOHP/CV (0.2 m x 0.8 m x 0.5 m) is made of copper tubes (inner diam, 2.03 mm). Working fluids were distilled water, ethanol and R134a. Waste heat from oven was recovered by heat exchanger and was beneficial for pre-heating the air in combustion process. Pre-heating was useful in burning glycerine, and distribution of heat inside oven with CLOHP/CV was better than without CLOHP/CV. Consequently, palm bunches received uniform heat that restrained enzyme thus slowing dissolution reactions that would otherwise produce free fatty acids and cause loss of palm oil. Use of a CLOHP/CV also reduced moisture content of palm bunches to 1.2 wt% on dry basis. When using oven with CLOHP/CV as a heat exchanger with R134a as working fluid, the highest thermal efficiency of drying palm bunch was 42.4%, highest effectiveness of CLOHP/CV was 43.0% and highest efficiency of glycerin stove was 45.0%