Himalayan Physics 2024-05-24T07:52:22+00:00 Himalayan Physics Open Journal Systems <p style="font-weight: 400;"><em>Himalayan Physics (HimPhys)</em> is a distinguished, open-access, peer-reviewed journal dedicated to publishing high-quality articles that make innovative contributions to various fields of physics. It is published annually by the Nepal Physical Society (Gandaki Chapter) and the esteemed Department of Physics at Prithvi Narayan Campus in Pokhara. The primary objective of HimPhys is to provide a platform that unites researchers and practitioners from both domestic and international academic communities, fostering a focused exchange on advanced techniques and the exploration of new frontiers within the physical sciences. By facilitating collaboration and knowledge-sharing, HimPhys aims to establish strong connections with the vibrant physics community in Nepal.</p> Lattice parameters prediction of orthorhombic oxyhalides using machine learning 2024-01-24T15:10:15+00:00 Poojan Koirala Madhav Ghimire <p>Lattice parameters of orthorhombic oxyhalides with molecular formula AOX are predicted using KRR, LR, and GBR machine learning (ML) models. Seventeen data of orthorhombic oxyhalides are extracted from the Materials Project Database, and several features such as atomic radius, ionic radius, band gap, density, electro-negativity, and atomic mass are taken into account. After refining the data, they are used for ML training and testing processes. The actual values of the respective compounds' lattice parameters are compared with those predicted by different models. Then, the accuracy of their predictions is checked by calculating MAE, MSE, and R<sup>2</sup>. The GBR model is more efficient in predicting lattice parameters 'b' and 'c', whereas KRR is found to be more more efficient in predicting 'a'. Further, using the random forest regression model, the features importance plot is also observed to understand which features play an important role in predicting the lattice parameters.</p> 2024-01-24T00:00:00+00:00 Copyright (c) 2024 Himalayan Physics Assessment of natural background radiation levels in Ranipokhari, Kathmandu, Nepal, following the 2015 earthquake and during reconstruction 2023-12-31T15:30:09+00:00 Hari Adhikari Roshan Chalise Himali Kalakhety Raju Khanal <p>Natural background radiation is present in the environment and its level can vary depending on the location, occurring radioactive elements in soil, water, and air. The measurement of natural background radiation in Ranipokhari, a historic pond in Kathmandu, is important as it is currently undergoing reconstruction after the 2015 earthquake. We used a Professional Digital Geiger Counter (GCA 07W) to measure the radiation dose at 50 different locations, 31 of which were on the outer corner of the pond and 19 were inside the pond. The minimum and maximum radiation exposure levels were found to be 49.80 μR/h and 147.48 μR/h, respectively, with an overall average exposure rate of (108.06 ± 3.47) μR/h. We observed that the count and exposure rates were higher on sunny days compared to rainy days. Hypothesis testing suggested that the average background exposure rate in Ranipokhari is higher than the world average external background radiation levels reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Our study provides crucial information on the natural background radiation levels in Ranipokhari, which can assist in the safe reconstruction of this historic pond after the earthquake.</p> 2024-05-12T00:00:00+00:00 Copyright (c) 2024 Himalayan Physics From the Hamilton-Jacobi equation to the Schrödinger equation and vice versa, without additional terms and approximations 2024-05-24T07:52:22+00:00 J.D. Bulnes M.A.I. Travassos D.A. Juraev J. Lopez-Bonilla <p>In this article, we will answer a question posed in the book Classical Mechanics by H. Goldstein: ``"Is the Hamilton-Jacobi equation the short wavelength limit of the Schrödinger equation?" But, before that, we will identify an essential element that will take us from the Hamilton-Jacobi equation to the dynamic equation of non-relativistic quantum mechanics for a function ψ through an exact procedure. This element is the linear independence of the functions ψ and ψ* (their complex conjugate). Their independence is demonstrated for physical systems where the acting physical potential does not explicitly depend on time. Proceeding in reverse, from the Schrödinger equation, we obtain the Hamilton-Jacobi equation, exactly, without additional terms.</p> 2024-05-24T00:00:00+00:00 Copyright (c) 2024 Himalayan Physics