http://thenucleuspak.org.pk/index.php/Nucleus <p><em>The Nucleus</em> is a well-established, open-access, peer-reviewed multidisciplinary scientific journal that has been in publication since 1964. The journal offers free access to all its content, both electronically and in print, ensuring that research is widely available to the public without any cost barriers. It is accredited as Y-category journal by the Higher Education Commission (HEC), and published biannually. <em>The Nucleus</em> invites research scholars, faculty members, and academicians from various disciplines, particularly in the natural and applied sciences, to submit their original research manuscripts. The journal is committed to promoting flawless and unbiased research, adhering to international publishing standards. The publisher also actively promotes published articles worldwide through various media channels, in line with open access regulations, ensuring that the research reaches a broad audience.</p> <p>The motto of <em>The Nucleus</em> reflects its dedication to transparency, integrity, and the promotion of high-quality research.</p> <p><strong><!--a href='#' id="fullscope" >Read More >></a--></strong></p> PAKISTAN ATOMIC ENERGY COMMISSION en-US The Nucleus 0029-5698 http://thenucleuspak.org.pk/index.php/Nucleus/article/view/1396 <p>The nuclear shielding properties of some metals like lead, copper, iron, aluminium and carbon were studied using 3ʺ×3ʺ. NaI(Tl) scintillation detector by the evaluation of shielding parameters such as the linear attenuation coefficient, and gamma-ray buildup factor. The linear attenuation coefficient of lead is very high compared to other materials used for the study. The buildup factors of these materials were observed to increase with the increase in the thickness of the material. The value of the buildup factor is found to be high at 662 keV and low at 1332 keV, and also the value of the buildup factors of lead is found to be very high compared to other materials used for the study.</p> Sheela M K.M. Eshwarappa Copyright (c) 2024 2024-10-15 2024-10-15 61 2 63 68 http://thenucleuspak.org.pk/index.php/Nucleus/article/view/1397 <p class="NuclAbstract">This work successfully utilized grey relational optimization in conjunction with the standard deviation objective weighting approach to improve various response parameters in a microchannel heat sink with pin fins, including: the surface Nusselt number and total surface heat flux. Six process parameters were chosen for the simulation research of the open microchannel heat sink with pin fins based on the L-27 orthogonal array. These parameters are heat sink length (L), heat sink width (W), number of fins (N), fin height (a), base height (b) and fin thickness (d). The surface Nusselt number and total surface heat flux were selected as the output parameters. This work aids in understanding the effect of various parameters on the open microchannel heat sink with pin fins. The standard deviation objective weighting - grey relational optimization method optimized the process parameters. ANSYS Fluent software was utilized to simulate the entire open microchannel heat sink with pin fins according to the L-27 orthogonal array. The optimal configuration for the process parameters was determined to be a heat sink length of 80 mm, width of 100 mm, 5 fins, fin height of 30 mm, base height of 8 mm and fin thickness of 2 mm. Among these parameters, the number of fins was found to be the most influential factor, followed by base height, fin thickness, width of the heat sink, fin height, and length of the heat sink. The findings indicate that these parameters play a critical role in the thermal performance optimization of microchannel heat sinks.</p> Syed Shamim Raza Ravi Bhushan Copyright (c) 2024 2024-10-15 2024-10-15 61 2 69 78