Thermal management has become a major issue in the latest high performance computing machines because high CPU temperatures result in inefficient performance and decreased hardware life span. In this work, the cooling performance of a finned metal foam heat sink (FMFHS) was examined. The pore density values of tested copper metal foam (CMF) samples with different values of PPI 5, 10 and 20, with a constant porosity of 90%. For reference, these samples were measured by a conventional Aluminum plate-fin heat sink (CHS). The work was performed under experimental conditions in which air directed over the heat sink surface at air velocities (2.5, 3.0 and 3.5 m/s). The environmental temperature was fixed at 27 °C. Findings indicated that pore density strongly affected on the cooling behavior. The 5-PPI foam showed an improved thermal performance better than CHS, due to the open pores and increased surface area, which enhance convective heat transfer. By contrast, the 10-PPI demonstrated moderate copper foam performance, placed between PPI 5 and CHS. The 20 PPI foam showed the lowest heat removal rates. Under these conditions, the 5 PPI design presented a 21.6 % increase in Nusselt number and a 16.9 % decrease in total thermal resistance at 3.5 m/s and 120 W compared to CHS. This confirms that using low PPI copper foams, such as 5-PPI in finned geometries, provides a considerable gain in cooling efficiency for high-power electronic components. Therefore, in high-power CPU cooling systems requiring high efficiency and compact size, it is recommended to use low PPI finned CMF heat sinks.
The research explores through its three parts, to search for the unconscious and the collective unconscious in order to identify the per-formative stimuli and motives and their motivation to produce a performance that is consistent with the metaphysics of the myth or the epic and its different characters from other human characters. The paper also explores in its second section a sort of sacred performance energy. Together, along with motivating the mind and engaging the subconscious, comes a metaphysical text and with its characters and epic events.
The goal of this experimental study is to determine the effects of different parameters (Flow rate, cuttings density, cuttings size, and hole inclination degree) on hole cleaning efficiency. Freshwater was used as a drilling fluid in this experiment. The experiments were conducted by using flow loop consist of approximately 14 m (46 ft) long with transparent glass test section of 3m (9.84 ft.) long with 4 inches (101.6 mm) ID, the inner metal drill pipe with 2 inches (50.8 mm) OD settled with eccentric position positive 0.5. The results obtained from this study show that the hole cleanings efficiency become better with high flow rate (21 m3/hr) and it increase as the hole inclination angles increased from 60 to 90 degree due to dominated
... Show MoreThe issue of penalized regression model has received considerable critical attention to variable selection. It plays an essential role in dealing with high dimensional data. Arctangent denoted by the Atan penalty has been used in both estimation and variable selection as an efficient method recently. However, the Atan penalty is very sensitive to outliers in response to variables or heavy-tailed error distribution. While the least absolute deviation is a good method to get robustness in regression estimation. The specific objective of this research is to propose a robust Atan estimator from combining these two ideas at once. Simulation experiments and real data applications show that the proposed LAD-Atan estimator
... Show MoreThe issue of penalized regression model has received considerable critical attention to variable selection. It plays an essential role in dealing with high dimensional data. Arctangent denoted by the Atan penalty has been used in both estimation and variable selection as an efficient method recently. However, the Atan penalty is very sensitive to outliers in response to variables or heavy-tailed error distribution. While the least absolute deviation is a good method to get robustness in regression estimation. The specific objective of this research is to propose a robust Atan estimator from combining these two ideas at once. Simulation experiments and real data applications show that the p
... Show MoreThermal and catalytic pyrolysis of waste plastics in an inert atmosphere has been regarded as a creative method, since pyrolysis can convert plastics waste into hydrocarbons that can be used either as fuels or as a source of chemicals.
Natural Iraqi kaolin clay was used to synthesis the NaX nano- zeolite by hydrothermal conditions with average particle size equal to 77.63nm.Thermal decomposition kinetics of high-density polyethylene (HDPE) in the absence and presence of catalysts nano NaX Zeolite was investigated. Thermal and catalytic degradation of HDPE was performed using a thermogravimetric analyzer in nitrogen atmosphere under non-isothermal conditions 4, 7 and 10 °C/min heating rates were employed in thermogravimetric anal
... Show MoreObjective Using two complementary techniques of virus detection human papillomavirus (HPV)[capture of hybrids (CH) and polymerase chain reaction (PCR)], relate the cytological study and/or cervical biopsy with high-risk HPV (HPV-HR) genotypes presence, as well as relating their viral load (VL). Methods About 272 women, who presented most cell alterations compatible with lesions cervical HPV, which has been detected in all high risk by the CH method and HPV genotype detection by PCR. Results In 22% of the patients it was not detected HPV DNA. Genotype 16 and/or 18 was prevalent and was found in 33% of the 212 women studied, meanwhile, mixed infections were found by several genotypes in 25%. In as for the histological lesions found, in 61 pat
... Show MoreBauxite residue (red mud) is a waste material from alumina refineries in the Bayer process, containing significant quantities of valuable metals, notably scandium (Sc). The objective of this study is to recover Sc (III) from Hungarian bauxite residue by using hydrometallurgical processes, including solvent extraction and leaching. Red mud directly leached with hydrochloric acid to generate the leachate solution. The significant iron content (~38 %) in red mud makes it hard to recover scandium selectively due to comparable physicochemical characteristics. According to the findings, Fe (III) could be effectively extracted from hydrochloric acid leachate as HFeC14 using diethyl ether before Sc extraction. Protocol B demonstrated superior recov
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