Applied Sciences and Chemical Engineering

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14540/111

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    Chemical characterization, enantiomeric distribution, and bioactivity analysis of essential oil from the selected lamiaceae plants of Nepal and their application in topical formulation
    (2023) Paudel,Prem Narayan; Rajendra Gyawali
    Essential oils (EOs) are complex mixtures of biologically active volatile compounds that have been utilized for a long time as flavoring agents, preservatives, and natural ingredients in many commercial products. In recent years, they have drawn great attention due to their increasing demand for food, cosmetics, and pharmaceuticals. Since many studies have revealed the good antimicrobial, antioxidant, and cytotoxic activities of essential oils, it is very important to characterize them based on their chemical profiles. In the present study, some selective plants from the Lamiaceae family of Nepal were collected to determine the chemical composition, enantiomeric distribution, and biological activities. The hydro-distilled essential oils were characterized for volatile compounds by Gas Chromatography and Mass Spectrometry (GC-MS), GC-Flame Ionization Detection (GC-FID), and enantiomeric composition by Chiral GC-MS. The chemometric analysis was applied to identify the chemotaxonomic relationship among Lamiaceae essential oils. The antimicrobial property was evaluated by the microbroth dilution method using some ATCC bacterial and fungal strains. The antioxidant activity was determined by DPPH and ABTS radical-scavenging assays. The in vitro cytotoxicity was evaluated in human breast cancer (MCF-7) and fibroblast (NIH-3T3) cell lines by using the Cell Counting Kit-8 kit assay. The antioxidant-rich essential oils were blended into the cream formulation. The results revealed the variation in the yield of essential oils with harvesting seasons. The species showed higher essential oil yield in the summer season and tropical regions than others. Ocimum tenuiflorum L. had the highest concentration (1.68±0.13%), and Leucosceptrum canum Sm. had the lowest yield among the samples (0.15±0.05%). The average essential oil yield obtained from the Lamiaceae plant species in Nepal was about 0.76%. Oxygenated monoterpenes were the dominant class of terpenoids present in most of the essential oil samples, with concentrations above 49%. Mentha pulegium L. showed the highest proportion of oxygenated monoterpenes (91.63%), followed by Mentha spicata L. (85.3%) and Perilla frutescens (L.) (83.05%). The lowest yield of oxygenated monoterpenes was found in Colebrookea oppositifolia Sm. at 0.89%. The single compound, carvone, was detected in the highest concentration for Mentha spicata L. oil (68.51%). The seasonal variations in the chemical composition of essential oils were also detected among the Lamiaceae samples. Origanum majorana L. comprises linalool and terpinen-4-ol as major compounds, with 13.8% and 32.1% in spring, and 15.37% and 33.35% in summer. Similarly, the carvone of M. spicata L. was not much influenced by seasonal variation, with 51.96% in winter and 68.51% in summer. Major constituents of O. tenuiflorum L., eugenol (32.15 to 34.95%), and trans-β-elemene (29.08 to 32.85%) were not much influenced by seasonal variation except minor ones. The same result was also detected in O. basilicum L., where methyl chavicol (62.16–64.42%) and linalool (26.92–27.09%) were not variable during the winter and summer seasons. A minor seasonal variation in the major compounds was observed for M. pulegium L. In contrast, the major constituents of L. canum Sm. were highly influenced by seasonal variations. The leading compound, β-pinene, of L. canum Sm. was found at 29.07% in winter, which decreased to 15.21% during summer. Similarly, another leading compound, β-caryophyllene, of L. canum Sm. was found at 13.29% in winter, which increased to 33.51% during summer, thereby indicating the seasonal variation in the chemical composition of Lamiaceae essential oils. In the chemometric analysis, agglomerative hierarchical cluster analysis for Lamiaceae essential oil showed two main groups of volatile classes: the first dominated by oxygenated monoterpenes and the second by sesquiterpene hydrocarbons. Both principal component analysis and clustered heatmaps confirmed the two distinct groups of volatile components as assigned by HCA. The chiral GC-MS revealed several chiral compounds in the essential oil samples. The α-thujene, αpinene, sabinene,β-pinene,camphene,limonene,1-octen-3-ol,linalool,α-terpineol,cis-sabinene hydrate, menthone, β-caryophyllene, terpinen-4-ol, germacrene D, borneol, β-bisabolene, δcadinene,(E)-β-ionone, and (E)-nerolodol were common chiral compounds in the EO,dominating in the levorotatory form (62.4%). In the DPPH assay, O. tenuiflorum L. exhibited relatively good antioxidant activity (IC50 69.2382.99µg/mL),when compared to the standards (ascorbicacid,IC50 6.37 µg/mL and BHT, IC5012.46 µg/mL), and in the ABTS aasay, this essential oil exhibited the strongest activity (IC505.88-17.69 µg/mL), when compared to the standards (ascorbic acid, IC50 1.98 µg/mL and quercetin, IC50 7.79 µg/mL). The least activity was noted in M. pulegium L. from Nuwakotduring the summer with an IC50 value of 646.58 µg/mL in the DPPH assay and with an IC50 valueof 145.35 µg/mL in the ABTS assay. The antioxidant activity M. spicata L., P. frutescens (L.), L.canum Sm., and O. majorana L. The essential oils obtained in the summer was higher as compared to the essential oils collected during the winter. In contrast, O. ameicanum L., O. basilicum L., and O. tenuiflorum L. The essential oils collected during winter exhibited higherantioxidant activity than those from the summer. The present study also revealed that the seasons and environmental conditions may influence the phytochemistry of plants, thereby affecting their antioxidant properties. Samples from tropical zones had better antioxidant activities than the other parts. The effect of these essential oil samples on the viability of human breast cancer (MCF-7) and fibroblast NIH-3T3 cell lines was also found to be significant. Among the Lamiaceae essentialoils, P. frutescens (L.) (IC50 7.41 and 8.14 µg/mL), C. umbrosum (M. Bieb.) C. Koch (IC50 21.70and 12.53 µg/mL), M. longifolia L.(IC50 23.76 and 12.12 µg/mL), and O. tenuiflorum L. (23.43µg/mL) samples were highly cytotoxic as compared to other species against both cell lines.While M. pulegium L., M. spicta L., P. glabar Benth., and O. basilicum L. essential oils displayed the least toxicity, with the IC50 values varying from 99.64 to 90.56 µg/mL. Among the essential oil studied against fungal strains, O. majorana L., M. pulegium L., and O. tenuiflorum L. were more effective against Candida albicans and Aspergillus niger (MIC, 78.1 µg/mL). O. majorana L. essential oil exhibited a broad spectrum of antimicrobial activity, with a MIC value of at least 156.3 to 312.5 µg/mL for all tested organisms. For anti-bacterial activity, only slight inhibition of these oils was found against all the tested bacterial strains. Similarly, the essential oils of O. majorana L., O. tenuiflorum L., and O. basilicum L. were utilized for the formulation of cream, which showed the retention of their best efficacy after extensive investigation of several pharmacological parameters. Hence, the present study concluded that the chemotaxonomic profiles of many essential oil samples from the Lamiaceae family of Nepal were prepared. They also exhibited excellent and varied biological efficacies, which can be useful in bioprospecting for the benefit of human health. Keywords: Lamiaceae, Essential Oil, GC-MS, Chemical Composition, Enantiomer, Antioxidant, Antimicrobial, Cytotoxicity, Formulation.
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    Synthesis and Electrochemical Characterization of Zinc Cobalt Bimetallic Oxide as an Advanced Positrode Material for Supercapacitor Application
    (Pulchowk Campus, 2025-11-25) Chakatu, Rabin; Shrestha, Khem Raj
    Facile cost-effective hydrothermal method successfully employed for synthesis of bimetallic oxides. XRD spectrum analysis confirmed spinel crystalline phase ZnCo2O4 nanoparticles with crystallites size expected to be in range of ~35 nm which aligns with the typical morphology of spinel ZnCo2O4 and FESEM of particle shows sea urchin like morphology with radially projecting nanoneedles structure
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    Synthesis and Characterization of Cobalt Cerium Co-doped Zinc Oxide Nanoparticles for Photocatalytic and Antimicrobial Applications
    (Pulchowk Campus, 2025-11-25) Adhikari, Madhusudan; Bhattarai, Deval Prasad
    This research investigates the synthesis and functional enhancement of zinc oxide (ZnO) nanoparticles through cerium (Ce) and cobalt (Co) doping for photocatalytic and antimicrobial applications. Pure ZnO, Ce-doped-, Co-doped-, and Ce–Co co-doped ZnO nanoparticles were synthesized via chemical co-precipitation method, followed by calcination at 500 °C.
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    Preparation of Activated Carbon from Jacaranda Seed Pods as Anode Material in Supercapacitors
    (Pulchowk Campus, 2025-05) Karki,Ashman; Mukhiya,Tanka
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    Black Carbon from Wildfires and Its Potential Impact on Surface Energy Balance of Khumbu Glacier, Nepal
    (Pulchowk Campus, 2025-05) Paudel,Aashutosh; Pradhananga,Dhiraj
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    Evaluating the Impact of Climate Change on Hydrological Extremes Using Deep Learning Method
    (Pulchowk Campus, 2025-05) Karki,Pramesh; Pandey,Vishnu Prasad
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    Climate Change Impact on Streamflow in the Chilime River Basin under CMIP6
    (Pulchowk Campus, 2025-05) Bhattarai,Kabita; Ghimire, Bhola Nath Sharma
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    Metal Organic Framework Decorated Hemp Hurd Derived Carbon for Energy Storage Application
    (Pulchowk Campus, 2025-05) Pal, Gyanendra; Mukhiya, Tank
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    “AMELIORATING THE MICRO-CLIMATE OF URBAN AREAS: -A CASE STUDY OF RESIDENTIAL COURTYARD BLOCK OF PATAN”
    (I.O.E. Pulchowk Campus, 2023-11) Aryal, Grishma
    The world is experiencing a crisis with climate change, and Nepal is among the most vulnerable nations. Urban areas, including those with heritage value, are experiencing an increase in air temperature due to the combined effects of climate change and the Urban Heat Island (UHI) effect. In order to lower UHI and raise outdoor thermal comfort, urban morphology is essential. Therefore, designers, planners or climatologists in order to make better microclimate and to improve thermal comfort consideration is necessary at planning phase. This paper presents a study of a major open area in a densely built and populated area in the centre of Patan to improve thermal comfort conditions in open spaces. This study focuses on the temporal-spatial analysis of how the geometry and vegetation of courtyards affect the outdoor thermal conditions in a warm, humid climate. This study will help to report the thermal environmental conditions of a courtyard open space in terms of vernacular dwelling space for present and future scenarios of climate change. This research will help to increase the comfort level of the people residing by improving indoor and outdoor thermal comfort in the courtyard with the use of appropriate construction techniques. It will also help in enhancing courtyards’ thermal conditions and contributing to an improvement of the surrounding urban
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    Thresholds and Characteristics for Heatwaves and Coldwaves in Nepal Between 1981-2020
    (I.O.E. Pulchowk Campus, 2023-11) Gupta, Adarsh
    With continuous climate change and global warming, temperature related hazards like: heatwave and coldwave must be monitored and studied, specially keeping in mind the geographical diverseness of Nepal where temperature related hazards can easily change into disasters. This study covers all the Nepal and with 40 years of statistical and climatological study of heatwaves and coldwaves unlike any other study of its kind. Also, this study attempts to provide nationalized standard criteria for monitoring heatwaves and coldwaves on district levels that has been severely lacking. With aim to determine percentile thresholds for heatwaves and coldwaves respectively and to characterize the past behaviors of both of these waves, this study analyzed the climatology and differences of heatwaves and coldwaves by using percentile method recommended by WMO based on last 40 years (1981-2020) of climatic data from 96 stations widely spread across the country. This study uses percentile method for computation of daily thresholds for heatwaves and coldwaves. Giving emphasis on 95th and 5th percentile value thresholds for heatwaves and coldwaves, these waves were identified. Also, this study extends to examine magnitude, frequency, spatial distribution and statistical comparison of these events.
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    Analyzing the Hydrological Regime of Sunkoshi River Basin, Nepal, using a Glacio-hydrological Degree-day Model (GDM)
    (I.O.E. Pulchowk Campus, 2023-12) BUDHATHOKI, SAILESH
    The Glacio-hydrological Degree-day Model (GDM), a distributed and gridded model in glacio-hydrology, uses a temperature index concept to calculate daily river discharge from snow and ice melt, rainfall and base flow. GDM calibration relies on factors like positive degree-days, snow and rain runoff coefficients and recession coefficient. The Sunkoshi River basin is a transboundary river between Nepal and Tibet. The study from 2000 to 2020 A.D includes calibration (2000-2009) and validation (2010-2020) phases in the model simulation. Its robust performance, reflected by Nash-Sutcliffe Efficiency (NSE) values between 0.79 to 0.77, volume difference below 10% and a strong R-squared (R2) value of 0.83 to 0.77, underscores its reliability. During calibration and validation, snowmelt contributes 9.68% to 11.38%, while clean ice and ice melt beneath debris account for 2.5% to 3% to the total discharge. Rainfall maintains substantial proportions at 48.26% to 50.15%, and baseflow ranges from 37.33% to 37.66% to the total discharge. In May to June's low-flow period, the study shows snow and ice melt greatly affect river discharge. Future analysis predicts a rise in ice melt's influence, especially during low-flow phases, impacting stream flow significantly. However, increasing temperatures reduce snowfall and glacier cover, to the point of diminishing ice and snow melt contributions, ultimately impacting future low-flow stream conditions.
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    Application of Glacio-hydrological degree-day Model to simulate hydrological regime of Tamakoshi River Basin, Nepal
    (I.O.E. Pulchowk Campus, 2023-12) CHAULAGAIN, NABIN
    The glaciers and snow-covered areas has been highly influential in the hydrology of the glacierized basin. Long-term water management will become more difficult as a result of climate change, which is anticipated to alter water availability. Here we have set up Glacio-hydrological Degree day Model Version 2 (GDM V.2) as a hydrological model to simulate the discharge in Tamakoshi River basin (TRB) and quantified various runoff components. The model is first calibrated and validated for the period of 2004-2009 and 2011-2020, respectively where Nash-Sutcliffe Efficiency (NSE) is 0.77 and 0.80 for calibration and validation periods. The monsoonal rain was anticipated to influence stream flow changes the most (46.86%), followed by base flow (37.57%), snowmelt (12.17%), and ice melt (3.18%) form the year 2004-2009 and rain (46.33%), followed by base flow (38.79%), icemelt (3.27%), and snowmelt (10.77%) from 2011-2020 according to the model. Forecasts indicate a rise in discharge under SSP58.5, notably reaching 3.68 m3/s according to EC-Earth3, in stark contrast to the declines projected under SSP24.5, such as the decrease to 0.09 m3/s under Nor ESM2-MM, between SSP24.5 and SSP58.5, constituent contributions exhibit significant variations, shedding light on potential shifts in resource availability.
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    COMPARATIVE ANALYSIS OF LONG SHORT-TERM MEMORY (LSTM) AND MULTI-LAYER PERCEPTRON (MLP) MODELS FOR RIVER RUNOFF PREDICTION IN THE HINDU KUSH HIMALAYAN REGION
    (I.O.E. Pulchowk Campus, 2023-12) Shrestha, Hansal
    Hydrological forecasting in the Hindu Kush Himalayas (HKH) presents special challenges because of the complex interplay between climatic and environmental factors. The quantitative predictive capabilities of two well-established models, Long Short-Term Memory (LSTM) and Multi-Layer Perceptron (MLP), chosen for their proven performance in previous studies, are meticulously compared in this thesis. The analysis uses comprehensive data spanning 2001 to 2013, including discharge records from the Department of Hydrology and Meteorology (DHM), precipitation data from APHRODITE, temperature data from APHRODITE, and snow cover area information from Google Earth Engine with MOD09A1 V6.1. The study employs rigorous evaluation metrics, revealing nuanced insights into the hydrological processes. Contrary to expectations, the MLP model exhibited slight superiority, showcasing a nuanced understanding of the region's complexities. The quantitative assessment, including RMSE (LSTM: 0.2396, MLP: 0.1733), MAE (LSTM: 0.1698, MLP: 0.0841), R2 Score (LSTM: 0.9976, MLP: 0.9987), and NSE (LSTM: 0.9976, MLP: 0.9987), emphasizes the indispensable role of robust predictive models, showcasing the necessity of reliable models for enhancing accurate river runoff predictions crucial for effective water resource management and flood preparedness in challenging terrains like the HKH.
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    Remote Sensing and GIS Based Assessment of Avalanching Glaciers in the Himalayas Due to Climate Change
    (I.O.E. Pulchowk Campus, 2023-12) Yadav, Pranav
    Hanging glaciers are a significant risk factor for avalanches, which can cause major disasters. Icefalls and avalanches from hanging glaciers pose a continuous threat to the regions beneath them. Therefore, it is imperative to invest in monitoring, analyzing, and modeling these phenomena. This will help to produce reliable forecasts, which can be used to take timely and efficient actions, such as evacuating areas. The analysis and modeling of avalanches can also help to improve our understanding of the underlying processes and influential factors. This can lead to the development of more effective early warning system. One approach to identifying potential avalanche zones is to use the Analytical Hierarchy Process (AHP) within a Geographic Information System (GIS) platform. This method has been proven effective for mapping avalanche-prone areas in rugged mountain landscapes. Another approach is to use a numerical simulation model such as the Rapid Mass Movement Simulation (RAMMS) model. This model can be used to simulate the flow dynamics of sites with potential avalanche activity. Both approaches have demonstrated their efficacy in predicting avalanche hazards in snowy and glacial environments. The goal of this study is to comprehensively address the societal impacts of avalanches, viewing them both as hazards and as disturbances within the environment. Keywords: Avalanche, Analytical Hierarchical Process (AHP), Hazard, Hanging glacier, Mass