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.
We have studied Bayesian method in this paper by using the modified exponential growth model, where this model is more using to represent the growth phenomena. We focus on three of prior functions (Informative, Natural Conjugate, and the function that depends on previous experiments) to use it in the Bayesian method. Where almost of observations for the growth phenomena are depended on one another, which in turn leads to a correlation between those observations, which calls to treat such this problem, called Autocorrelation, and to verified this has been used Bayesian method.
The goal of this study is to knowledge the effect of Autocorrelation on the estimation by using Bayesian method. F
... Show MoreThis research aims at clarifying the concept of social auditing, which is one of the most important reasons for its emergence is social responsibility accounting and its role in measuring the social performance of enterprises. The study also aimed to know how social auditing has an impact and its role in improving the social performance of business organizations, and the research refers to testing the hypotheses of an impact of social auditing on social performance through a commitment to social responsibility. The research sample consisted of 200 individuals from 20 Algerian business organizations and represented individuals who were researched in managers and em
... Show MoreStudent performance may influence by several factors in all his study levels such as primary school, intermediate school and even in his college; some of these factors are psychological factors, social factors, and the factors which correlate with student environment.
In this paper we study some of these factors to discover their influence by using canonical correlation analysis to analyze the data. Many conclusions are discovered to help who focuses student performance or to make it pest in future.
The Experiment was carried out to determine the level vibration transfer in three axes Horizontal X, Lateral Y and Vertical Z direction to seat driver tractor, Vector sum of vibration and Daily Vibration Exposure (8 hours) in seat driver tractor, and vibration in steering wheel tractor, Heart Rate, Systolic and Diastolic blood pressure and temperature were measure to all Drivers before and after used Chisel plow in operation tillage. Statistical analysis system was used, Split-Split Plot Design under Randomized Complete Block Design, Three factors were used in this experiment included Two types of Soil Moist and Dry soil which represented main plot, Three Velocity Tractor was second factor included 1.6,3.5 and 5.4 km/hr and Three Drivers Tr
... Show MoreThere has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide very low bit error rates (BER) along with information security. As more and more information is transacted over wireless media, there has been increasing criminal activity directed against such systems. This paper investigates the feasibility of using chaotic communications over Multiple-Input-Multiple-Output (MIMO) channels. We have studied the performance of differential chaos shift keying (DCSK) with 2×2 Alamouti scheme and 2×1 Alamouti scheme for different chaotic maps over additive white Gaussian noise (
... Show MoreIn this work, the performance of the receiver in a quantum cryptography system based on BB84 protocol is scaled by calculating the Quantum Bit Error Rate (QBER) of the receiver. To apply this performance test, an optical setup was arranged and a circuit was designed and implemented to calculate the QBER. This electronic circuit is used to calculate the number of counts per second generated by the avalanche photodiodes set in the receiver. The calculated counts per second are used to calculate the QBER for the receiver that gives an indication for the performance of the receiver. Minimum QBER, 6%, was obtained with avalanche photodiode excess voltage equals to 2V and laser diode power of 3.16 nW at avalanche photodiode temperature of -10
... Show MoreThis research aims to study to the strategic management of organizational conflict, which included (concept of conflict and development, types Altzimi conflict, ,management strategies organizational conflict) and its impact on job performance, which included( the concept of performance, elements functionality,) As well as the impact of the conflict on job performance has been selected Rashad training Hospital affiliated to the Department of Health in Baghdad's Rusafa, as the most important service hospitals with the exact specialty in psychiatry and its impact on the lives of citizens and how to enable the hospital aware of the strategic management of organizational conflict raises the level of functionality provided and make the
... Show MoreIn the petroleum industry, multiphase flow dynamics within the tubing string have gained significant attention due to associated challenges. Accurately predicting pressure drops and wellbore pressures is crucial for the effective modeling of vertical lift performance (VLP). This study focuses on predicting the multiphase flow behavior in four wells located in the Faihaa oil field in southern Iraq, utilizing PIPESIM software. The process of selecting the most appropriate multiphase correlation was performed by utilizing production test data to construct a comprehensive survey data catalog. Subsequently, the results were compared with the correlations available within the PIPESIM software. The outcomes reveal that the Hagedorn and Brown (H
... Show MoreNanocomposite films of silver-polyvinyl alcohol (Ag/PVA) with varying silver nanoparticle concentrations (1-5 wt%) were synthesized via a solution casting technique. The films were characterized by understanding the influence of Ag content on their structural, optical, mechanical, and electrical properties. UV-Vis spectroscopy (300-800 nm) revealed a red shift in absorption peaks and a significant decrease in the optical band gap from 5.39 eV to 1.06 eV with increasing Ag concentration, indicating the formation of additional energy states within the PVA matrix. FTIR and SEM analyses confirmed the successful incorporation of nanoparticles and revealed changes in surface functionalities and morpholog