Scientific World <p>A Multidisciplinary Peer Reviewed Annual Journal of Science and Technology published by the Ministry of Education, Science and Technology, B.P. Koirala Memorial Planetarium, Observatory and Science Museum Development Board, Kirtipur, Kathmandu, Nepal.</p> en-US (Sanat Kumar Sharma) (Sioux Cumming) Thu, 20 Jun 2024 12:01:45 +0000 OJS 60 Further investigation of perturbations in FLRW space-time <p>The solutions of perturbation equations in FLRW spacetime were further analysed for indications of structure formation. The radial and angular parts of the wavefunction reveal various possibilities of spatial and angular sizes in terms of quantum numbers ω, k, l and m. They offer slightly contrasting results for the three cases of the closed, open and flat universes including for each of all the 3 modes of perturbations – scalar, vectorial and tensorial. It is seen that the structures of large scales are more compact in the closed case, slightly diffuse in the flat one. Also structures of different sizes are more probable in the open case.</p> Prem Raj Dhungel, Sanat Kumar Sharma, Uday Raj Khanal Copyright (c) 2024 Scientific World Thu, 20 Jun 2024 00:00:00 +0000 First principles study of structural equilibrium configuration of Ortho-, Meta-, and Para-chloroaniline molecules <p>This work has studied the ground state energy, binding energy, equilibrium geometry, charge distribution, and dipole moment of ortho-, meta-, and para-chloroanilines using a wide range of advanced theoretical methods including first-principles Hartree-Fock (HF), Mϕller-Plesset (MP) perturbation theory, Configuration Interaction (CI) and Density Functional Theory [DFT (B3LYP)] with basis sets 3-21G, 4-31G, 6-31G, 6-31G*, 6-31G**, 6-311G, 6-311G*, and 6-311G**. The trend in ground state energy is obtained in E<sub>DFT</sub> &lt; E<sub>HF+MP3</sub> &lt; E<sub>HF+MP2</sub> &lt; E<sub>CISD</sub> &lt; E<sub>HF</sub>. The calculated binding energies for these molecules in DFT calculations using the 6-311G** basis set are determined to be 7590.61 KJ/mol, 7589.14 KJ/mol, and 7586.73 KJ/mol respectively. The positive binding energy values occur in all these molecules indicate the stability of the molecule. The bond length between carbon (C) and chlorine (Cl) in ortho, meta and para chloroaniline is determined to be 1.769 Å, 1.765 Å, and 1.765 Å respectively. In calculation at the HF+MP2 level, the C-Cl bond length for ortho, meta, and para chloroaniline molecules are determined to be 1.742 Å, 1.741 Å, and 1.740 Å respectively. There is a reduction in the C-Cl bond length when the chlorine atom's position in chloroaniline changes from ortho to meta and then to para positions. The values of bond angle and dihedral angle for these molecules at the HF, HF+MP2, and DFT (B3LYP) levels of calculation are nearly equal. The distribution of charges in each molecule results in a net sum of Mulliken charges equal to zero. The calculated dipole moments for ortho, meta, and para chloroaniline molecules are 2.1194 Debye, 3.5398 Debye, and 4.1385 Debye, respectively.</p> Krishna Bahadur Rai, Nabin Kumar Teemilsina, Bijay Siwakoti Copyright (c) 2024 Scientific World Thu, 20 Jun 2024 00:00:00 +0000 Activated carbon derived from coffee waste as supercapacitor electrode material <p>Activated carbon prepared from waste coffee (seed powder) was investigated as a potential low-cost electrode material for supercapacitors. Energy Dispersive X-ray Spectroscopy (EDS) of the activated carbon detected the presence of a high amount of carbon (~93.9%) and oxygen (~5.2%). X-ray diffraction (XRD) analysis indicated the presence of graphitic carbon whereas Raman spectra showed a slightly greater content of amorphous carbon than graphitic carbon. Nitrogen adsorption-desorption isotherm of the activated carbon revealed that most of the pores in the activated carbon were micropores. The dominant pore width calculated from the Density Functional Theory (DFT) and Brunauer-Emmett-Teller (BET) surface area of the activated carbon were measured to be 1.61 nm and 825.5 m<sup>2</sup>g<sup>-1</sup>, respectively. The electrochemical characterization was performed by cyclic voltammetry and galvanostatic charge-discharge test in 3 M KOH electrolyte. The activated carbon electrode obtained a specific capacitance of 113.81 F g<sup>-1</sup> at 1 A g<sup>-1</sup>. Thus, activated carbon from waste coffee could be a promising low-cost electrode material for supercapacitors.</p> Omkar Khadka, Umesh Lawaju, Sunil Koju, Ram Chandra Rai, Mim Lal Nakarmi, Prakash Joshi Copyright (c) 2024 Scientific World Thu, 20 Jun 2024 00:00:00 +0000 Frontier molecular orbitals, MEP, NBO, and vibrational spectra of Mesalamine: A first principle study from DFT and molecular docking approaches <p>The main purpose of this work is to investigate the structural, electronic, and vibrational features of mesalamine (C<sub>7</sub>H<sub>7</sub>NO<sub>3</sub>) from density functional theory (DFT) approach. The optimized structure has been obtained from DFT calculation by using the functional B3LYP/ 6-311++G(d,p) basis set. The spectroscopic feature (FT-IR and FT-Raman) of the investigated compound has been calculated from the same level of theory. The molecular electrostatic potential (MEP) analysis is used to identify the distribution of charge around the compound. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) have been studied and their energy gap (∆E<sub>L-H</sub>) L is used to study the chemical potential (μ), hardness (n), softness (S) and electrofilicity index (ω) of the molecule. The electron transfer property has been scrutinized from natural bond orbital (NBO) analysis. Additionally, molecular docking was carried out to identify binding sites and the binding behavior of the ligand with a predicted target protein (Carbonic anhydrase II).</p> Manoj Kumar Chaudhary, Sudip Pandey, Poonam Tandon Copyright (c) 2024 Scientific World Thu, 20 Jun 2024 00:00:00 +0000 Silver nanorod: green synthesis and their electronic, optical and antibacterial properties <p>Synthesis of nanomaterials has been the subject of a lot of interests due to its commercial demands and wide applicability in various fields such as chemistry, physics, biology, material science, engineering, medicine etc. This paper reports the green synthesis of silver nanorod. For synthesis, silver nitrate solution was used as a metal precursor and aqueous extract of root of <em>Beta vulgaris</em> was used as a reducing agent. Four different sets of samples were synthesized by varying the reduction time to study the size dependent electronic and optical properties. The formation of nanostructure was confirmed by presence of surface plasmon resonance in absorption spectra. Optical band gap calculation was done by using absorption spectroscopy. Absorption spectroscopy showed that the maximum absorption was red shifted when the reaction time was increased, indicating the increasing size of material. Similarly, it was found that the optical band gap was decreased with increasing reduction time. Moreover, the antimicrobial activity of synthesized nano silver was studied against both the gram negative<em> (Pseudomonas aeruginosa, Escherichia coli)</em> as well as gram positive bacteria<em> (Staphylococcus</em> aureus).</p> Rojita Pant, Sabita Shrestha Copyright (c) 2024 Scientific World Thu, 20 Jun 2024 00:00:00 +0000 Prediction of lattice parameters of tetragonal oxyhalides AOX <p>Machine learning enables computers to emulate human intelligence for complex data analysis and pattern<br />recognition. This work utilizes machine learning to predict lattice parameters in tetragonal oxyhalide compounds with molecular formula AOX. Four supervised learning methods - random forest regression, gradient boosting regression, support vector regression, and kernel ridge regression - are employed to forecast lattice parameters from features including atomic radii, ionic radii, atomic masses, electronegativities, band gaps, formation energies, and densities. Model accuracy is evaluated using mean absolute error and R<sup>2</sup> as regression scoring measures. An analysis of gradient boosting regression determines the predictive capacity of distinct features toward lattice parameters. Comparisons identify kernel ridge regression as optimal for predicting lattice constant <em>a</em>, with the highest R<sup>2</sup> of 0.840; whereas gradient boosting shows superior in modeling lattice parameter <em>c</em> with a maximum R<sup>2</sup> reaching 0.948. This research demonstrates the successful application of machine learning methodologies for predicting material properties, enabling the estimation of lattice parameters in tetragonal oxyhalides.</p> Kashmira Malla, Madhav Prasad Ghimire Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Uptake of Arsenic and Lead ions by the adsorbent material prepared from physiochemical modification of spinach leaves <p>Physiochemically modified adsorbent material from spinach was prepared by refluxing for 12, 24 and 36 hours in ortho phosphoric acid solution with in the temperature range between 60 - 100 °C. The highest specific surface area of 436 m<sup>2</sup>/g was obtained with refluxing for 24 hours sample (SA-24) and was selected for the adsorption of As(III) and Pb(II) ions from the aqueous solution with varying several parameters such as pH, kinetics, and concentration of adsorbent.</p> <p>The adsorbent before and after adsorption of As(III) and Pb(II) was characterized by FTIR and XRD. Studies showed that the maximum efficiency at pH 5 for As(III) and Pb(II). Kinetics and isotherm model studies demonstrated that the experimental data fitted with pseudo-second order and Langmuir isotherm model with the rate constants 2.495 and 0.039 g/(mg·min) and the maximum adsorption capacities 116.28 and 128.21 mg/g for As(III) and Pb(II), respectively. The negative free energy (ΔG values -23 and -25 kJ/mol for As(III) and Pb(II), respectively) in adsorption process revealed the spontaneous nature and feasibility of the adsorption process onto spinach adsorbent. The values of ΔG further confirmed that the adsorption process was favored by physiochemical adsorption for As(III) and Pb(II), respectively.</p> Brijesh Kumar Das, Vinay Kumar Jha Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Estimation of nitrogen and phosphorus in fertilizers found in Nepalese market and some soil samples <p>Soil fertility is the basis for agriculture, soil acts as a crucial reservoir of plant micronutrients including the major elements such as nitrogen and phosphorus which largely determine plant health and crop productivity. The availability of nutrient absorption largely depends on the soil pH and soil moisture content as it affects the soil’s chemical, physical, and biological properties and plays a key role in agricultural productivity.</p> <p>In this study, 15 soil samples were collected from Thecho, Gokarna and Pathivara Yangwarak to measure moisture content, soil pH, nitrogen and Phosphorus content and 6 samples of fertilizers from the Nepalese market were selected for their nitrogen and Phosphorus content. Soil moisture was found in the range of 16.57 – 28.40 % and soil pH was found in a slightly acidic to nearly neutral with pH value in the range of 6.5 – 7.0. Nitrogen content was estimated by the Kjeldahl method and phosphorus content was estimated by Olsen's method. Among 15 soil samples, phosphorus in 11 soil samples were found high value, 3 soil samples were found medium value and 1 soil sample were found low value and nitrogen in 5 soil sample were found high, 5 soil samples were found medium and 5 soil samples were found low value. In most of the fertilizers, nitrogen and phosphorus content were found much lower than labeled in the packet.</p> Arvind Pathak, Tara Limbu Ijam, Akrasha Tamang, Manoj Nidhi Wagle Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Evaluation of antioxidant, antibacterial and antidiabetic activities of different parts of Litsea polyantha extracts <p>The genus Litsea consists of about 700 species of evergreen trees or shrubs and is widely distributed in tropical and subtropical countries of the world. <em>Litsea polyantha</em> is used in traditional medicine around the world to cure a variety of illnesses such as influenza, diarrhea, stomach aches, diabetes, vomiting, and central nervous system. The antioxidant, antibacterial, and antihyperglycemic activity of <em>Litsea polyantha</em> were investigated. The antioxidant activity was performed by DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay, and hyperglycemic activity was performed by α-amylase inhibition. The toxicity of plant extracts was assessed by brine shrimp lethality assay (BSLA) using <em>Artemia salina</em> as a biological test organism. The total phenolic content was found high in bark extract 182.49 ± 8.18 mg GAE/g and the total flavonoid content was found maximum in the same bark extract 71.23±2.68 mg QE/g. Bark extract and leaf extract showed the highest DPPH radical scavenging activity with an IC<sub>50</sub> of 36.06±2.94 μg/mL and 20.46±1.05 μg/mL. For a methanolic extract of bark, ZOI was observed as 14±0.58 mm, 13±3.18 mm, and 11±0.33 mm against <em>Bacillus subtilis</em>, <em>Staphylococcus aureus</em>, <em>Klebsiella pneumoniae</em>. Similarly, for leaf, root, and stem extract ZOI was observed 10 ± 0.57 mm, 11 ± 0.67 mm, and 9 ± 0.58 mm against <em>Staphylococcus aureus</em>, <em>E. Coli</em>, and <em>Bacillus subtilis</em>. Bark extract and leaf extract had IC<sub>50</sub> of 0.72±0.03 mg/mL and 2.40±0.02 mg/mL respectively. The LC<sub>50</sub> of 835.35 μg/mL for the root extract of <em>Litsea polyantha</em> was shown to be toxic against brine shrimp. This study showed the different parts of <em>Litsea polyantha</em> are rich sources of phenolic and flavonoid content and the potential natural antioxidant and antidiabetic compounds that could be isolated</p> Sumana Bhattarai, Khaga Raj Sharma Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Biological activity and GC-MS determination of bioactive components of Clerodendrum viscosum (Vent.) from Siraha District, Nepal <p><em>Clerodendrum viscosum</em> has a long history of medical use in Asian countries with a variety of bioactivities. Although the chemical constituents of plants are strongly influenced by their surroundings, little is known about the chemical composition and biological activity of <em>C. viscosum</em> that is growing in Nepal's Siraha District. Therefore, the aim of this study was to evaluate the total phenolic content, flavonoid content, and biological activity, GC-MS analysis of <em>C. viscosum</em> leaves that was collected from the Siraha District. The methanolic extract of <em>C. viscosum</em> leaf was prepared and the phytochemicals were assessed, its TPC and TFC were estimated, and antioxidant and α-amylase inhibitory activities were determined following standard methods. Hexane soluble fraction of methanol extract of <em>C. viscosum</em> was subjected for GC-MS analysis. The TPC of the extract was found to be 197.68±0.11 mg GAE/g and its TFC was 105.14±0.026 mg QE/g. The IC<sub>50</sub> value for DPPH free radical was found to be 26.85 0.150 g/mL, while the IC<sub>50</sub> value for α-amylase enzyme activity was found to be 121.48 0.424 g/mL. The presence of several bioactive components was revealed by the GC-MS chromatogram, with phytol being a major constituent.</p> Shivdev Yadav, Santosh Kumar Yadav, Bimala Subba Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Phytochemical evaluation of Aglaomorpha coronans from Nepal <p>The rhizomes of <em>Aglaomorpha coronans</em> is used to cure back pain by the local people of Lamjung district. The medicinal value depends on the presence of biologically active phytochemicals with drug like properties. Phytochemical evaluation of <em>A. coronans</em> of Nepalese origin has not been reported yet. Hence, the present study is focused on the phytochemical analysis, evaluation of antioxidant, antibacterial activities of various extracts and GC-MS profiling of ethyl acetate extract. The rhizomes were extracted with the hexane, chloroform, ethylacetate, methanol and 50% aqueous methanol. Phytochemical screening of ethyl acetate, methanol and 50% aqueous methanol extracts showed the presence of phenolics, flavonoids, tannins and sugar. Their total content as well as antioxidant activity were determined. The highest amounts of phenolics, flavonoids and tannins were detected in the ethyl acetate extract (292.144±1.829 mg GAE/g, 322.904±3.942 mg CE/g, 516.666±0.423 mg TAE/g). The highest amounts of sugars were detected in the methanol extract (205.649±0.169mg GE/g). In DPPH radical scavenging assay, ethyl acetate extract showed the highest activity (IC<sub>50</sub> 37.545 μg/ml). The chloroform, ethyl acetate and methanol extracts showed antibacterial activity against <em>S. aureus</em>. GC-MS analysis of ethyl acetate extract showed the presence of more than 20 compounds. However, 9 compounds, mainly polyol, low molecular weight phenolic acids and terpenes/sterols were identified by comparing the mass fragmentation pattern of each compound with the standard NIST mass spectral database. The presence of 3,4-dihydroxy benzoic acid, Olean-13(18)-ene and β-sitosterol justifies the anti-inflammatory and analgesic properties of <em>A. coronans</em> in traditional medicine.</p> Alisa Koirala, Agnidhar Devkota, Meena Rajbhandari Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Preparation of zinc oxide nanoparticles using Citrus sinensis fruit peel aqueous extract and its antimicrobial study <p>The remarkable properties of nanoparticles within the 1 to 100 nm size range have garnered significant attention due to their unique characteristics arising from their small size and high surface-to-volume ratio. In this research, zinc oxide nanoparticles (ZnO NPs) were synthesized using an eco-friendly approach, employing orange fruit peel aqueous extract as a stabilizer as well as biological reducing agent and zinc nitrate hexahydrate as a zinc precursor. This method not only reduces the need for copious amounts of chemicals but also eliminates the use of hazardous substances in the fabrication process, augmenting the antibacterial attributes of the nanoparticles. As synthesized material underwent characterization through X-ray diffraction (XRD) analysis where the prepared material was single phase crystalline ZnO NPs and particle size was measured to be 31.2 nm using Debye-Scherrer’s equation. Energy-dispersive X-ray spectroscopy (EDX) revealed that the sample primarily consisted of 98% zinc with minor impurities such as calcium and potassium in it. Fourier-Transform Infrared (FTIR) analysis exhibited a distinct absorption peak at approximately 550 cm⁻¹, confirming the synthesis of ZnO NPs. The antimicrobial potential of the synthesized ZnO NPs was evaluated against two bacterial strains, Staphylococcus aureus and Escherichia coli, through the Kirby Bauer method on media conducive to bacterial growth. The prepared nanoparticles exhibited bactericidal activity, effectively inhibiting bacterial growth, and generating discernible zones of inhibition.</p> Yinit Raj Lamichhane, Kshama Parajuli, Situ Shrestha Pradhanang Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Photocatalytical Degradation of Methyl Orange using laboratory prepared Copper Oxide photocatalyst <p>Copper oxide materials have been successfully synthesized by the chemical precipitation method using copper nitrate, sodium hydroxide and sodium lauryl sulphate. As prepared materials were characterized by using XRD and FTIR. The XRD data reveals that as prepared CuO is crystalline in nature. The particle size of the material was found to be approximately 10 nm indicating nano-sized particle. Photocatalytic efficiency of CuO nanoparticle was then studied. In this study, methyl orange (MO) was used as model dye pollutant. The MO degradation rate using CuO photocatalyst was studied at different pH condition, varying time of UV irradiation, variation of catalyst dose. Results revealed that the optimum pH was found to be 3 and optimum time was found to be 150 min using optimum dose of 0.05g under UV light irradiation in presence of H<sub>2</sub>O<sub>2</sub> in MO dye solution. The rate constant of MO degradation was found to be 0.0099 min<sup>-1</sup> indicating good rate of reaction which was in agreement with literature value 0.0089 min<sup>-1</sup>.</p> Armila Rajbhandari Nyachhyon, Gobinda Neupane Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Fungicidal activity of seeds of Abrus precatorius L., Datura metel L., and Diploknema butyracea (Roxb.) H.J. Lam against phytopathogenic fungi <p>This study aimed to investigate the antifungal activity of seeds of <em>Abrus precatorius</em> L., <em>Datura metel</em> L. and <em>Diploknema butyracea </em>(Roxb.) H.J. Lam against common phytopathogenic fungi. The powdered seeds were extracted by Soxhlet extraction method using methanol as a solvent. Antifungal activity was performed by poison agar technique with different concentrations ranging from 5 to 20% of seed extracts against two fungal pathogens -<em> Fusarium oxysporum</em> f. sp. <em>cubense</em> R4 (<em>Foc</em>R4) and <em>Rhizoctonia</em> spp. Among three plant seed methanolic extracts at 5% concentration, <em>D. metel</em> seeds showed significant inhibition with 69.81±3.30% percentage inhibition of diameter growth (PIDG) against <em>Foc</em>R4 on 8th day and 77.51±3.00% PIDG <em>Rhizoctonia</em> spp. on 5th day. All the plant seed extracts showed complete inhibition against mycelial growth at ≤10% concentration. UV-visible spectroscopy spectra showed the peaks at 238 nm and 280 nm wavelengths for the seed extracts of <em>A. precatorius</em> L., and <em>D. metel</em> L., respectively while <em>D. butyracea</em> (Roxb.) H.J. Lam showed the peaks at 206 nm and 262 nm. These peaks were assumed to represent the antifungal compounds. The antifungal activity of the plant extracts could be attributed by the phytochemicals present in crude seed extracts. Although further studies are necessary, our data indicate that seeds of the examined three plants are potential biofungicides which could substitute for chemical fungicides.</p> Elina Maharjan, Mui-Yung Wong, Umesh Thapa, Rameshwar Adhikari, Dev Raj Joshi Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Remarkable photocatalytic performance of zinc oxide nanoparticles prepared through green synthetic method by using Citrus limon dry peel extract <p>Zinc oxide nanoparticles (ZnO NPs) were synthesized through green synthetic method using <em>Citrus limon</em> (Lemon) dry peel extract which acts as a reducing agent. The synthesized nanoparticles were yellowish white and their UV-vis spectra showed the characteristic maximum peak at 332 nm which affirmed the formation of zinc oxide nanoparticles. For further confirmation, the synthesized nanoparticles were characterized through X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM) and High-Resolution Transmission Electron Microscopy (HR-TEM). The most intense peak in the XRD pattern was selected for crystallite size determination by using the Scherrer’s equation; the average crystallite size was computed to be 19 nm. FE-SEM results demonstrated the spherical shape of nanoparticles with less distinct morphology. The hexagonal structure of ZnO NPs was identified by HR-TEM. ZnO NPs showed excellent catalytic activity of 50.25% photodegradation of MB under natural sunlight irradiation for 120 minutes. The results show that the as-synthesized ZnO NPs can have possible application in water treatment for removing harmful dyes. The phytochemical screening of dry <em>Citrus limon</em> peel extract revealed the presence of alkaloids, flavonoids, cardiac glycosides, saponins, terpenoids, tannins, and reducing sugar.</p> Sushan Waiba, Motee Lal Sharma, Kamal Prasad Sapkota Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 Bacteriological profile of ready-to-eat food items in Kathmandu <p>Ready-to-eat (RTE) food items are defined as the foods prepared or cooked in advance, with no further cooking or preparation required before being eaten. Consumption of ready-to-eat foods prepared in an unhygienic environment can lead to different types of food-borne illnesses ranging from mild self-limiting ones to severe food poisoning leading to mortality. The goal of this study was to see if the ready-to-eat foods available in Kathmandu was contaminated with bacteria and to determine the antibiotic susceptibility pattern of the isolated bacteria. A total of 100 ready-to-eat foods (momo &amp; sauce, chowmein, pizza, thakali set, burger and samosa) were gathered from various locations around Kathmandu and analyzed by standard microbiological methods in the Microbiology Department of Tri-Chandra Multiple Campus from March to August 2022. Out of 100 samples analyzed, 55 showed the presence of bacteria; <em>Escherichia coli</em> was found to be predominant (52.72%), followed by <em>Bacillus cereus</em> (16.38%) and<em> Salmonella</em> spp (12.72%), among others. Momo and its sauce contained highest number of bacteria, followed by chowmein and burger; the least number of bacteria was found in samosa and pizza. Antibiotic susceptibility test was performed against all isolated bacteria following standard disc diffusion method. The bacterial isolates were sensitive towards Meropenem and Ceftriazone whereas they were resistant towards Ampicillin and Nalidixic acid. One bacterial isolate<em> (Klebsiella pneumoniae)</em> showed Multi Drug Resistance (MDR) which was also an ESBL (Extended Spectrum Beta Lactamase) producer. Significant presence of bacteria in ready-to-eat food items indicate the unhygienic practice of food preparation and handling and can pose threat to the health of general public. It also emphasizes the need for regular monitoring of food items to reduce the risk of food associated illnesses.</p> Charu Arjyal, Sagarika Manandhar, Shraddha Dulal Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000 On solutions of convection-diffusion equation in fluid <p>Convection and diffusion are fundamental transport mechanisms that govern the flow of mass, heat, or other quantities in various physical, biological and engineering systems. The work overviews theoretical underpinnings, mathematical formulations and numerical methods to analyze the convection-diffusion process in one and two dimensions, both in steady and transient states. We have compared the analytical and numerical results using finite difference and finite volume methods for fluid flow and temperature distribution. The numerical solutions are in agreement with the analytical solution in one dimension. The work compares convection-diffusion with convection-dominating for larger velocities of fluid flow. The solution obtained from FVM is in line with an analytical solution than the solution obtained from FDM. The numerical simulation for the transient flow is also discussed.</p> Uddhab Raj Nyaupane, Kedar Nath Uprety, Buddhi Prasad Sapkota Copyright (c) 2024 Scientific World Tue, 18 Jun 2024 00:00:00 +0000