Journal of Institute of Science and Technology <p><em>Journal of Institute of Science and Technology </em>(JIST) is a peer-reviewed multidisciplinary science journal published by the Institute of Science and Technology (IOST), Tribhuvan University (TU), Kathmandu, Nepal.</p> en-US <p>The views and interpretations in this journal are those of the author(s). They are not attributable to the Institute of Science and Technology, T.U. and do not imply the expression of any opinion concerning the legal status of any country, territory, city, area of its authorities, or concerning the delimitation of its frontiers of boundaries.</p> <p>The copyright of the articles is held by the Institute of Science and Technology, T.U.</p> (Prof. Dr. Chhatra Mani Sharma) (Sioux Cumming) Mon, 21 Jun 2021 11:00:08 +0000 OJS 60 A Review on Current Practices of Plastics Waste Management and Future Prospects <p>Inefficient solid waste management of plastics and polymeric materials is one of the global challenges leading to environmental deterioration. This challenge has brought alarming concern to minimize volume of such wastes released into the environment. The concern proposes a solution to the existing problems to some extent by reuse, recycling, and efficient conversion of waste materials into alternative application. Chemical and thermo-mechanical conversion of plastic wastes into energy and their biodegradation were taken into account. Consequently, some newly employed recycling and conversion techniques of plastic wastes, and possible future alternatives with recommendations are reviewed in this article</p> Netra Lal Bhandari, Sulakshana Bhattarai, Ganesh Bhandari, Sumita Subedi, Kedar Nath Dhakal Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Status of Air Pollution over the Last Three Decades in Thimphu City, Bhutan <p>With an increasing human population and vehicles, air pollution in Thimphu City is growing and causing a risk to human health, properties, and ecosystems. The population of Thimphu was 79,185 in 2005 but in 2017 it surged up to 114,551. An increase in the human population has also led to the rising demands for vehicles and thus increased the vehicular emissions in the area. Additionally, the use of traditional fuels, burning of waste and agriculture residues, forest fire, and transboundary pollutants are other sources resulting in poor air quality in Thimphu City. Air pollution data from journal articles, government documents, reports from national and international organizations, and books were reviewed. Concentrations of PM<sub>10</sub>, PM<sub>2.5</sub>, SO<sub>2</sub>, NO<sub>2</sub> were increasing over the decades. The annual average PM<sub>10</sub> recorded in Thimphu was 28&nbsp;µg/m<sup>3</sup> in 2005, 47&nbsp;µg/m<sup>3</sup> in 2010, 43&nbsp;µg/m<sup>3</sup> in 2014, and 42&nbsp;µg/m<sup>3</sup> in 2015. Winter months were found to have higher PM<sub>10</sub> and PM<sub>2.5 </sub>concentrations. The 24-hourly average concentrations of SO<sub>2</sub> ranged from 0.0 to 6.9&nbsp;µg/m<sup>3</sup> and NO<sub>2</sub> 8.2-26.6&nbsp;µg/m<sup>3</sup>. There is a need for comprehensive studies to identify spatial and temporal variations in the ambient concentration of the pollutants in the area. Strict enforcement of the legal frameworks is essential for the mitigation of air pollution in Thimphu City.</p> Govinda Prasad Sharma, Ramesh Prasad Sapkota, Enna Mool, Tulsi Gurung, Rejina Maskey Byanju Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Anticancer Potency of Copper(I) Complexes Against a Range Cancer Cell Lines: A Review <p>The copper(I) complexes of N,N-diimine, N,O- and/or N, S-bidentate systems perform significant dose-dependent anticancer activity toward various cell lines <em>viz.</em> MCF-7, LNCap, PSN-1, A431, BxPC3, H157, A2780, HeLa, MDA-MB231, MGC-803 etc. The copper(I) complexes can cross the cellular plasmalemma that results in the accumulation of copper ion&nbsp; in the cancer cells, exhibit significant anticancer effect and overcome the multidrug resistance because these can slightly induce the DNA cleavage as a result of limited generation of reactive oxygen species (ROS). Copper(I) complexes exhibit significantly higher broad-spectrum antiproliferation and cell apoptosis <em>via</em> mitochondrial pathway than that of their corresponding Cu(II), Co(II), Pd(II), and Ni(II) complexes. The copper(I) complexes inhibit the cancer cells not only <em>via</em> ROS generation but also <em>via</em> DNA interactions possibly by attacking the sugar-phosphate backbone of DNA due to their oxidative and partial dissociation behavior. Copper(II/I) complexes are also able to cleave DNA by hydrolytic pathway and induce caspase-dependent-mitochondrial-mediated cell apoptosis by ROS production or blocking the progression of cell cycles. In many cases, the modification in organic moiety and the placement of electronegative substituent near the metallic center of complexes have been found to enhance their anticancer potency in a significant manner. Thus copper(I) complexes may be used as the better anticancer drugs with multiple modes of action compared to the copper(II) complexes due to having oxidative behavior and generation of empty site on copper(I) ion during partial dissociation.</p> Narendra Kumar Singh, Paras Nath Yadav Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Study of Spatial Orientation of Angular Momentum of z-Magnitude SDSS DR-13 Galaxies with Red Shift 0.50 to 0.53 <p>The spatial orientations of 142,929 SDSS DR-13, z- magnitude galaxies having red shift 0.50 to 0.53 have been analyzed. The main goal of this work is to examine the orientation of the angular momentum of galaxies within the given redshift limit in the framework of three different scenarios 'Hierarchy model', 'Pancake model', and the 'Primordial vorticity model'.&nbsp; By using Godlowskian transformation the two-dimensional data were converted into three-dimensional data (polar and azimuthal angles). The expected isotropy distribution curves were obtained by removing the selection effects and performing a random simulation to generate 10<sup>7</sup> virtual galaxies by using Matlab 2015a. Three statistical tests of Chi-square, autocorrelation, and Fourier were used to compare the expected isotropic data with observed. The data classified into nine subsamples having each of one magnitude size. In general, the results supported the Hierarchy model. The model advocates random orientations of angular. However, a local anisotropy observed in few subsamples suggested a gravitational tidal interaction between neighboring galaxies, an early-merging process in which the angular momentum vector distorts the initial alignment of nearby galaxies.</p> Shiv Narayan Yadav, Santosh Kumar Sah Copyright (c) 2021 Institute of Science and Technology, T.U. Wed, 16 Jun 2021 00:00:00 +0000 Fermentation and Extraction of Antibacterial Metabolite Using Streptomyces spp. Isolated from Taplejung, Nepal <p>Realizing an increasing need for a novel antibiotic, this study was carried out to screen antibacterial metabolites producing actinomycetes from 15 soil samples collected from Taplejung. Antibacterial metabolites producing actinomycetes were confirmed by primary screening and secondary screening. Macroscopic, microscopic, and biochemical characteristics were used for presumptive identification of probable actinomycetes genera<em>.</em> The potential isolate was cultured in starch casein broth for production of possible antibacterial compound. The antibacterial compound was extracted from fermented broth using organic solvents like ethyl acetate, n-butanol, chloroform, dichloromethane, and methanol. Among 24 isolates, only one (T<sub>18</sub>) showed antibacterial activity against both Gram-positive (<em>Staphylococcus aureus</em> and <em>Bacillus</em> <em>subtilis</em>) and Gram-negative (<em>Escherichia coli</em>, <em>Salmonella</em> Typhi and <em>Pseudomonas</em> <em>aeruginosa</em>) test-bacteria<em>.</em> The isolate was considered as <em>Streptomyces </em>spp based on microscopy and various biochemical, and physiological characteristics. Extracted antibacterial metabolite showed antibacterial activity with a MIC value of 1.2 mg/mL against <em>E. coli </em>(ATCC 25922). The chromatogram in Thin Layer Chromatography showed only one spot exhibited by extract with R<sub>f </sub>value 0.87 suggested that the isolate produced a compound that was completely different from the spot with R<sub>f</sub> value 0.94 produced by gentamicin (standard). This study revealed the distribution of the potent antibacterial metabolite producing actinomycetes in the soils of Taplejung.</p> Shiv Nandan Sah, Ramesh Majhi, Sunil Regmi, Arjun Ghimire, Bhageshwor Biswas, Lalu Prasad Yadav, Ranjit Kumar Sah, Pradeep Kumar Shah Copyright (c) 2021 Institute of Science and Technology, T.U. Wed, 16 Jun 2021 00:00:00 +0000 Statistical Downscaling and Projection of Future Temperature and Precipitation Change in Gandaki Basin <p>Understanding the present and future spatial and temporal variations of precipitation and temperature is important for monitoring climate-induced disasters. Satellite and global reanalysis data can provide evenly distributed climate data; however, they are still too coarse to resolve fundamental processes over complex terrains. The study applies global climate model CGCM4/CANESM2, to project future maximum temperature, minimum temperature, and precipitation across the cross-section of the Gandaki River basin, Nepal. Large scale atmospheric variables of the National Centre for Environmental Prediction/National Centre for Atmospheric Research reanalysis (NCEP/NCAR) datasets are downscaled using Statistical Downscaling Model (SDSM) under different emission scenarios. For the variability and changes in maximum temperature (T<sub>max</sub>), minimum temperature (T<sub>min</sub>), and precipitation for future periods (2020s, 2050s, and 2080s), three different scenarios RCP2.6, RC4.5, and RCP8.5 of CGCM4 model were performed. The study revealed that both the temperature and precipitation would increase for three RCPs (representative concentration pathways) in the future. The highest increase in precipitation was found in the arid region compared to humid and sub-humid regions by the end of 2100. Similarly, the increase in mean monthly T<sub>min </sub>and T<sub>max </sub>was more pronounced in Jomsom station than Baglung and Dumkauli stations. Overall, a decrease in summer temperature and increase in winter temperature was expected for future periods across all regions. Further, spatial consistency was observed for T<sub>max</sub> and T<sub>min</sub>, whereas spatial consistency was not found for precipitation.</p> Dibas Shrestha, Shankar Sharma, Sandeep Bhandari, Rashila Deshar Copyright (c) 2021 Institute of Science and Technology, T.U. Wed, 16 Jun 2021 00:00:00 +0000 Application of Numerical Methods for the Analysis of Damped Parallel RLC Circuit <p>A sudden application of sources results in time-varying currents and voltages in the circuit known as transients. This phenomenon occurs frequently during switching. A simple circuit constituting a resistor, an inductor, and a capacitor is termed an RLC circuit. It may be in parallel or series configuration or both. Different values of damping factors determine the different nature of the transient response. We applied different numerical solution methods such as explicit (forward) Euler method, third-order Runge-Kutta (RK3) method, and Butcher's fifth-order Runge-Kutta (BRK5) method to approximate the solution of second-order differential equation with initial value problem (IVP). We thoroughly compared the numerical solutions obtained by these methods with the necessary visualization and analysis of error. We also examined the superiority of these methods over one another and the appropriateness of numerical methods for different damping conditions is explored. With high accuracy of the approximation and thorough analysis of the observation, we found Butcher's fifth-order Runge-Kutta (BRK5) method to be the best numerical technique. Regarding the different values of damping factors, we considered the further possibility of discussion and analysis of this iterative method.</p> J. Kafle, B. K. Thakur, I. B. Bhandari Copyright (c) 2021 Institute of Science and Technology, T.U. Wed, 16 Jun 2021 00:00:00 +0000 Ecology and Diversity of Ectomycorrhiza in moist Tropical Forest of Sunsari District, Eastern Nepal <p>An ectomycorrhiza plays a vital role in the maintenance and strengthening the forest ecosystems and diversity. This study attempts to assess the ecology and diversity of ectomycorrhiza in tropical Sal (<em>Shorea robusta</em> Gaertn.) forest in Sunsari district, eastern Nepal. The collection of ectomycorrhiza was carried out from June to September (rainy season) for the year 2019-2020. A total of 18 species of ectomycorrhiza belonging to 12 genera and 7 families were collected.&nbsp; Russulaceae was found to be the dominant family representing 7 species. As per the diversity indices, the Shannon Weiner index and Simpson’s index were found to be 2.60 and 0.913, respectively indicating a higher value for the index of diversity. The results conclude that the moist tropical forest of Sunsari district is rich in ectomycorrhizal fungi, which consequently may provide a great opportunity for nutrient absorption</p> Sabitri Shrestha, Tilak Prasad Gautam, Tej Narayan Mandal, Hari Prasad Aryal Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Structural, Electronic and Magnetic Properties of Defected Water Adsorbed Single-Layer MoS2 <p>Water adsorbed in MoS<sub>2</sub> (w<sub>ad</sub>-MoS<sub>2</sub>), 1S atom vacancy defect in w<sub>ad</sub>-MoS<sub>2 </sub>(1S-w<sub>ad</sub>-MoS<sub>2</sub>), 2S atoms vacancy defects in w<sub>ad</sub>-MoS<sub>2</sub> (2S-w<sub>ad</sub>-MoS<sub>2</sub>), and 1Mo atom vacancy defect in w<sub>ad</sub>-MoS<sub>2</sub> (Mo-w<sub>ad</sub>-MoS<sub>2</sub>) materials were constructed, and their structural, electronic, and magnetic properties were studied by spin-polarized density functional theory (DFT) based first-principles calculations. The w<sub>ad</sub>-MoS<sub>2</sub>, 1S-w<sub>ad</sub>-MoS<sub>2</sub>, 2S-w<sub>ad</sub>-MoS<sub>2,</sub> and Mo-w<sub>ad</sub>-MoS<sub>2</sub> materials were found stable. From band structure calculations, w<sub>ad</sub>-MoS<sub>2</sub>, 1S-w<sub>ad</sub>-MoS<sub>2</sub> and 2S-w<sub>ad</sub>-MoS<sub>2</sub> materials open energy bandgap of values 1.19 eV, 0.65 eV and 0.38 eV respectively. Also, it was found that the conductivity strength of the material increases with an increase in the concentration of S atom vacancy defects in the structure. On the other hand, the Mo-w<sub>ad</sub>-MoS<sub>2</sub> material has metallic properties because energy bands of electrons crossed the Fermi energy level in the band structure. For the investigation of magnetic properties, the density of states (DoS) and partial density of states (PDoS) calculations were used and found that w<sub>ad</sub>-MoS<sub>2</sub>, 1S-w<sub>ad</sub>-MoS<sub>2</sub>, and 2S-w<sub>ad</sub>-MoS<sub>2 </sub>are non-magnetic materials, while Mo-w<sub>ad</sub>-MoS<sub>2 </sub>is a magnetic material. The total magnetic moment of Mo-w<sub>ad</sub>-MoS<sub>2</sub> has a value of 2.66 µ<sub>B</sub>/cell, due to the arrangement of unpaired up-spin and down-spin of electrons in 3s &amp; 3p orbitals of S atoms; and 4p, 4d &amp; 5s orbitals of Mo atoms in the material.</p> Hari Krishna Neupane, Narayan Prasad Adhikari Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Comparison of Thermo-physical Properties of Mg-Ga and Mg-Pb Alloys at 1000 K <p>Concentration-dependent thermophysical properties of molten Mg-Pb and Mg-Ga alloys at 1000 K was compared using the Redlich Kister equation by optimizing exponential interaction energy parameters based on the R-K polynomials framework.&nbsp; The mixing behavior was investigated by giving more emphasis to the role of temperature-dependent interaction energy parameters. Our study shows that the magnesium gallium alloy is slightly interacting than the magnesium lead alloy. The surface tension and viscosity of both alloys was compared using the Butler equation as improved by Kaptay and KRP (Kozlov-Ronanov-Petrov) approach respectively. The surface tension of Mg-Pb liquid alloy increases but decreases in Mg-Ga alloy with an increase in the concentration of Mg. The viscosity has a nonlinear variation for both alloys with the increase in the concentration of magnesium.</p> N. Panthi, I. B. Bhandari, R. C. Pangeni, I. Koirala Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Decadal Evolution of Landslides in the Siwalik Zone: a Case Study of Babai Watershed, Nepal <p>The Siwalik zone of the Nepal Himalaya is highly sensitive to landslides. The study of landslides in the catchment scale gives the basic concept of the overall landslides of the typical zone. In this study, the decadal evolution trend of the four largest landslides of the Babai River watershed was evaluated. The Landsat, Sentinel-2, and Google Earth imageries were used to obtain the physical data of the landslide from 2010 to 2019. The area, total length, and width of scar toe, and the body of landslides were obtained from the images. The rainfall data of two stations was used to evaluate the role of rainfall in the landslide development and evolution process. The trend of rainfall and area of landslides was not the same but the development process of all four landslides was more or less similar. The area of landslides fluctuated till 2014 but suddenly increased after 2015. The landslide area was highest in 2017 and moderately changed in 2018 and 2019. The landslides showed dynamic behavior in a decade with their typical expanding, widening, and reducing characters.</p> Bharat Prasad Bhandari, Subodh Dhakal Copyright (c) 2021 Institute of Science and Technology, T.U. Fri, 18 Jun 2021 00:00:00 +0000 Quickest Flow Algorithms with Time-Varying Attributes <p>In many real-world situations, there are numerous network optimization problems where the network attributes depend on time. In this paper, we consider single-source single-sink discrete-time dynamic network flow problems. We review some algorithms for the quickest flow problems in two environments (to the network attributes): time-invariant and time-variant. This paper mainly focuses on the existing algorithms for a later one. In literature, most of the authors have made their objectives to determine the earliest arrival time paths along which a given amount of flow can be sent in the minimum time. Evacuation is the most recent research area of network optimization, where quickest flow models allow the estimation of the minimum time required to bring a given number of evacuees to safety.</p> Dipak Babu Amgain, Tanka Nath Dhamala Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Topological and Reactivity Descriptor of Carisoprodol from DFT and Molecular Docking Approach <p>This study aims to investigate the optimized structure and optimized parameters of carisoprodol from the DFT/B3LYP/6-31G(d,p) level of theory. The molecular electrostatic potential (MEP) map signifies that the positive potential across hydrogen of the amine group (NH<sub>2</sub>) and the negative potential around the carbonyl groups (C=O). HOMO-LUMO energy gap was found to be 8.1064 eV. The global and local reactivity parameters describe the possible chemical reactive sites in the molecule. The topological analysis of the electron localization function (ELF) and localized orbital locator (LOL) revealed that the charge localization around hydrogen atoms. The hyper-conjugative interaction between donor and acceptor orbital showed that the interaction LP(2) O4→ σ*(O2-C16) plays a vital role in the molecular stability. The molecular docking simulation encircles that the carisoprodol behaves as a good inhibitor with the target protein, Tyrosine-protein kinase ABL.</p> Tarun Chaudhary, Manoj Kumar Chaudhary, Bhawani Datt Joshi Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Analysis of L2 Regularization Hyper Parameter for Stock Price Prediction <p>Nowadays stock price prediction is an active area of research among machine learning researchers. One of the main problems with machine learning models is overfitting. Regularization techniques are widely used approaches to avoid over-fitted models. L2 regularization is one of the most popular and widely used regularization techniques. Regularization hyperparameter (ʎ) is one key parameter to be optimized for a well-generalized machine learning model. Hyperparameters can’t be learned by machine learning models during the learning process. We need to find their optimal value through experiments. This research work analyzed the L2 regularization hyperparameter used with a gated recurrent unit (GRU) network for stock price prediction. We experimented with five stocks from the Nepal Stock Exchange (NEPSE) and observed that stock price can be predicted with lower mean squared errors (MSEs) when the value of ʎ was around 0.0005. Therefore, this research paper recommended using ʎ=0.0005 with L2 regularization for stock price prediction.</p> Arjun Singh Saud, Subarna Shakya Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Impact of Flow Variation on Hydropower Projects in Budhigandaki River Basin of Nepal <p>Daily flow data from 1964 to 2015 of Budhigandaki River at Arughat were analyzed to assess the impact of flow variation at different time scales to the run of the river (RoR) type of hydropower projects. The data show very high inter-annual variation in daily, monthly and seasonal flows. The long term annual average flow at Arughat was 160 m<sup>3</sup>/s and varies from 120 to 210 m<sup>3</sup>/s. The long-term averages of loss in flow for both dry and wet seasons based on daily flows for three design discharges (Q<sub>90</sub>, Q<sub>60</sub> and Q<sub>40</sub>) were found to be respectively -0.72, -1.76 and -1.54 m<sup>3</sup>/s for dry season and 0.0, -0.27 and -2.26 m<sup>3</sup>/s for wet season.&nbsp; Although long-term average loss is small, uncertainty increases with the increase in design discharge. The long-term dry season power loss is about 3 % for the RoR projects of the basin however, its annual variation is large. There is a probability of losing the quantum of energy generation by nearly 40% in some years and gaining by about 30 % in some other years in dry season. The impact of flow variation on power production was negative in both dry and wet seasons for RoR projects of Budhigandaki basin. This study concludes that uncertainty arising from daily flow variation should be assessed while estimating energy generation in hydropower projects. Intra-annual flow variation is, thus, to be taken into consideration while calculating the power generated by the RoR plants; and it should be reflected in power purchase agreement.</p> Suresh Marahatta, Laxmi Prasad Devkota, Deepak Aryal Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000 Bacterial Etiology of Bronchoalveolar Lavage Fluid in Tertiary Care Patients and Antibiogram of the Isolates <p>Bronchoalveolar Lavage (BAL) is a medical technique by which cells and fluids from bronchioles and lung alveoli are withdrawn for diagnosis of disease or evaluation of treatment. Patients with various pulmonary infections follow the procedure of BAL for the disease diagnosis as it has high sensitivity and reliability in diagnosis. To examine the bacterial etiology of BAL fluids among tertiary care patients with pulmonary infections, a cross-sectional study was conducted over a period of three months from August to November 2018. A total of 149 BAL fluid samples were examined and the bacterial agents were isolated and identified by conventional microbiological methods. Out of the 149 samples, 142 samples were culture positive. Among 6 different isolates (4 Gram-negative and 2 Gram-positive), <em>Pseudomonas aeruginosa </em>(45 %) was predominant followed by <em>Klebsiella pneumoniae</em> (25.3 %). A higher infection rate was seen among males (62.4 %) and in the age group 60-70 years (30.0 %). In addition, 25.4 % (36/149) samples were positive in Acid Fast staining. Bacterial recovery from the BAL fluid was significantly associated with the gender and age of the patients (p&lt;0.05). Gentamycin was the least resisted (1.5 %) by Gram-negative isolates followed by Polymyxin-B (3 %). For Gram-positive isolates, Ofloxacin was the most effective drug resisted by none of the isolates followed by Gentamycin. Among the 157 isolates, 125 (79.6 %) were MDR and 35.0 % of Enterobacteriaceae were ESBL producers. Detection of bacterial agents from BAL fluid can be a basis for successful antimicrobial therapy for patients with pulmonary infections.</p> Sanjib Adhikari, Ramesh Sharma Regmi, Siddanta Pandey, Parash Paudel, Nischal Neupane, Shyam Chalise, Ashok Dubey, Sarad Chandra Kafle, Komal Raj Rijal Copyright (c) 2021 Institute of Science and Technology, T.U. Thu, 17 Jun 2021 00:00:00 +0000