Nepal Journal of Science and Technology <p><em>Nepal Journal of Science and Technology</em> is a peer-reviewed open access journal published by Nepal Academy of Science and Technology (NAST). Full text articles are available. </p> Nepal Academy of Science and Technology (NAST) en-US Nepal Journal of Science and Technology 1994-1412 <p>Authors retain copyright and grant the journal right of first publication.</p> Isolation and Characterization of Plant Growth promoting Rhizobacteria from Bamboo Rhizosphere and Their Role in Plant Growth Promotion <p>Plant growth-promoting rhizobacteria (PGPR) are a group of root-associated bacteria that intimately interact with the plant roots and consequently enhance growth by extemporising nutrient retrieval or phytohormone production. We isolated and screened indigenous phosphate solubilising and auxinproducing PGPR from bamboo rhizosphere. 66 soil samples from bamboo (<em>Bambusa nutans</em> subsp. <em>cupulata</em>, <em>B. balcooa</em> and <em>B. tulda</em>) rhizospheres were collected from Dhanusha, Mahottari and Sarlahi districts, Nepal. 120 isolates of PGPR were obtained by serial dilution method in (PVK) agar and Luria Bertani agar. 92 out of 120 isolates of PGPR with the ability to solubilise phosphate were selected based on the halo colony ratio in PVK agar medium and auxin production in Luria Bertani agar. Among them, six isolates having high phosphate solubilising index and high production capacity of indole-3-acetic acid were further screened. Biochemical analysis revealed that these isolates belonged to the genus <em>Pseudomonas</em>. Phosphate solubilising index and indole-3- acetic acid production by six isolates ranged from 4.19±0.8 to 7.65±1.3, and IAA production ranged from 72.93±0.2 to 82.48±0.9µg/ml respectively. These isolates significantly increased shoot length (13.26±0.56cm), shoot fresh weight (16.26±1.02mg), shoot dry weight (10.56±0.09mg), root length (4.9±0.5cm), root fresh weight (7.56±1.05mg), root dry weight (3.21±0.01mg), and chlorophyll ‘a’ and chlrophyll‘b’ and carotenoid (2.16±0.01mg/g, 1.19±0.06mg/g and 0.92±0.01mg/g respectively) of <em>B. nutans</em> subsp. <em>cupulata</em> seedlings. This study suggests that PGPR isolated from bamboo rhizosphere demonstrated outstanding contribution to the growth promotion of seedlings of <em>B. nutans</em> subsp. <em>cupulata</em> as compared to negative control.</p> Bishnu Maya K.C Dhurva Prasad Gauchan Sanjay Nath Khanal Janardan Lamichhane Copyright (c) 2022 2022-12-31 2022-12-31 21 1 1 12 10.3126/njst.v21i1.49908 In vitro Induction and Proliferation of Callus in Piper longum L. through Leaf Culture <p><em>Piper longum</em> L. (Family Piperaceae) is a well- known health promoter used to treat cough, chronic bronchitis, asthma, and diabetes mellitus. The study is aimed to develop a protocol for callus induction and proliferation in <em>P. longum</em>. The leaf explants from mature plants were cultured on an MS basal medium supplemented with various concentrations of plant growth hormones, viz. 2,4-Dichlorophenoxyacetic acid (2, 4-D), Kinetin (KN), 6-Benzylaminopurine (BAP), and α-Naphthalene acetic acid (NAA), as well as 10% coconut water. In primary culture, the callus was compact and light white. The best callus induction and growth were observed in the MS basal medium containing1.0 mg/L 2,4-D+ 2.0 mg/L KN at 12 weeks of primary culture. At eight weeks of secondary culture, the MS medium containing 2.0 mg/L BAP alone and 0.5 mg/L NAA + 2.0 mg/L BAP and 10% coconut water had the best callus proliferation. Compared to 2,4-D and KN alone, BAP alone supported rapid callus growth in the MS medium. In <em>P. longum</em>, large-scale callus formation from leaf explants could be exploited to produce, isolate, and increase bioactive secondary metabolites for therapeutic purposes.</p> Chandra Bahadur Thapa Krishna Kumar Pant Hari Datta Bhattarai Bijaya Pant Copyright (c) 2022 2022-12-31 2022-12-31 21 1 13 22 10.3126/njst.v21i1.49892 Soil Carbon Fluxes and Sensitivity Analysis – A Study in Pinus roxburghii Forest <p>The predicted increasing atmospheric carbon dioxide (CO<sub>2</sub>) level is responsive to altering the future climate, and a small change in the soil carbon may significantly affect the forest carbon cycle and climate system. Soil respiration (SR) and its influencing factors like soil temperature (ST), soil water content (SWC) and surface litter-fall were measured monthly over one year in a sub-tropical Pine (<em>Pinus roxburghii</em>) forest of Bhaktapur district located in central Nepal to determine the SR of the forest and, its variations and sensitivity. The results showed that SR varied to the changes in ST by an exponential significant positive correlation between them. The optimum SR was observed between 10 and 22ºC, and the highest SR were obtained above ST at 20ºC. The temperature sensitivity value of SR (Q<sub>10</sub>) was estimated at Q<sub>10</sub> = 2.13. The significant exponential curve represented the effect of SWC on SR. The higher SR rate was mostly measured between 10 and 25% SWC. The monthly and seasonal variations of the SR rate were consistent with the ST, SWC and litter-fall variations. The study showed that the combined effect of temperature and precipitation might be the major cause of SR variations; however, ST is adequate for increasing SR. Hence, the warming further enhances carbon emission from the forest floor and inversely increases carbon to contribute to climatic change through this pine-dominated forest stand structure.</p> Deepa Dhital Bikash Gosain Sanu Raja Maharjan Copyright (c) 2022 2022-12-31 2022-12-31 21 1 23 36 10.3126/njst.v21i1.49909 Development of Numerical Modeling for Finding Reflection and Transmission Coefficients in an Engineering Learning Paradigm of Computational Thinking <p>In electromagnetics and antenna engineering, reflection and transmission coefficients are important parameters to be evaluated statistically and numerically to obtain effective computer simulations. This paper proposes a pedagogy to understand the development methodology of numerical reflection and transmission coefficient models. The proposed method employs relatively easy mathematics instead of the conventional ways that use difficult mathematics. These are then simulated as computer models. The study in this paper included a medium comprising of air and glass placed in it. Firstly, the region was divided into a gridded structure where the grids were mathematically formulated. Points on the grid were distinguished between different media using electrical permittivity and conductivity. The grids included boundary conditions and electric field wave propagation through them. Both boundary conditions and field equations were numerically modelled and discretized using the finite difference method with a proportional h2 error. This method provided a system of linear equations, which were then solved linearly to obtain the required reflection and transmission coefficients. An important aspect of the presented work is to provide an example approach for computational thinking (CT), which is now considered an important part of any engineering curriculum</p> Ikram E. Khuda Copyright (c) 2022 2022-12-31 2022-12-31 21 1 37 44 10.3126/njst.v21i1.49959 Identification of Cucurbit Fruit Flies and Their Relative Attractiveness to Different Cues and Releasers <p>Tephritids are the major challenges for fruit and fleshy vegetable growers of the tropics and subtropics. Nepal also incurs huge losses of fruits and vegetables to the tephritids. This study was designed to identify the tephritid flies in Malepatan and Lumle of Gandaki Province. Bucket traps baited with methyl eugenol (ME) in Malepatan, and ME, cue lure (CL) and a mixture of ME and CL (ME+CL) with different releasers; tube, cotton and paper were installed at Lumle in 2020 summer. Three species of the fly (<em>Bactrocera dorsalis</em>, <em>Bactrocera zonata</em> and <em>Bactrocera correcta</em>) were recorded from Malepatan, dominated by <em>B. dorsalis</em>. The <em>B. correcta</em> count was negligible. While in Lumle, <em>B. dorsalis</em> was the most dominant, followed by <em>B. zonata</em> till July, after which, till August,<em> B. ta</em>u followed the <em>B. dorsalis</em>. Seven species of the tephritids (<em>B. zonata</em>, <em>B. dorsalis</em>, <em>B. tau</em>, <em>B. diversa</em>, <em>B. scutellaris</em>, <em>B. correcta</em> and <em>B. cucurbitae</em>) were recorded from this region. Among the releasers, paper releaser was found more effective as compared to cotton and tube. However, the lures should be changed in a short interval, by two weeks, to acquire a satisfactory result. This study unveils that the study site already inhabits seven species of fruit flies. So, the monitoring with different cues could be an effective tool for species actuation. Additionally, the paper releasers could be recommended for further use in the traps for monitoring and mass trapping purposes.</p> K Chiluwal E Shrestha S Devkota K Shrestha S Sigdel A Khanal RB Basnet B Upadhyay LN `Aryal Copyright (c) 2022 2022-12-31 2022-12-31 21 1 45 56 10.3126/njst.v21i1.49911 Oidium (powdery mildew: Erysiphales) Parasitic on Mangifera indica L (Mango) in Nepal: A Taxonomic Approach <p><em>Oidium</em> species parasitic on mango leaves (<em>Mangifera indica</em> L.) was gathered from Bhanimandal, Lalitpur, Nepal. The previous studies done from Nepal has been revised based on study of recent collection, available literature and reports. It was concluded that the fungus was <em>Erysiphe quercicola</em> S. Takam. &amp; U. Braun</p> Mahesh Kumar Adhikari Copyright (c) 2022 2022-12-31 2022-12-31 21 1 57 60 10.3126/njst.v21i1.49912 Phytochemical Screening and Evaluation of Antioxidant and Antibacterial Potential of Selected Species of Gentiana from Nepal Himalaya <p>Various species of <em>Gentiana</em> find their use to treat various digestive and topical ailments in traditional medicine in Nepal. The present work reports the results of preliminary phytochemical analysis and biological activities of extracts of four different species of Gentiana (<em>G. depressa</em>, <em>G.ornata</em>, <em>G. urnula</em>, and <em>G. capitata</em>) from Nepal Himalaya. Furthermore, the study also reports a semi-quantitative estimation of major bioactive compounds in those extracts. The total flavonoid content was found to be highest (19.09±0.97mgQE/g) in methanol extracts of <em>G. capitata</em> and lowest (4.22±0.66 mgQE/g) in aqueous extracts of <em>G. urnula</em>. The highest amount (79.2±19.19 mgGAE/g) of total phenolic content was observed in methanolic extracts of <em>G. depressa</em>, while the lowest amount (37.11±2.18 mgGAE/g) was observed in aqueous extract of <em>G. urnula</em>. The methanol extract of <em>G. depressa</em> showed the best antioxidant activity among the <em>Gentiana</em> species tested. Extracts of all the species tested showed weak antibacterial activity even at the highest concentration of the extract. Semi-quantitative estimation showed that swertiamarin was in higher quantities than amarogentin and mangiferin. The highest concentration of swertiamarin and mangiferin (0.109±0.013 mg/g and 0.018±0.001 mg/g, respectively) was identified in <em>G. ornata</em>, while the highest concentration of amarogentin (0.075±0.005 mg/g) was observed in <em>G. capitata</em>. These results justify the folklore use of these species in traditional medicinal practices in Nepal.</p> Niroj Shakya Supreet Khanal Giri Prasad Joshi Deepak Raj Pant Copyright (c) 2022 Niroj Shakya, Supreet Khanal, Giri Prasad Joshi, Deepak Raj Pant 2022-12-31 2022-12-31 21 1 61 72 10.3126/njst.v21i1.49913 A Short-Term Measurement of PM2.5 Concentration During the COVID-19 Lockdown Period in Kathmandu Valley <p>The Government of Nepal implemented a nationwide lockdown from 24 March 2020 to 21 July 2020 to control the person-to-person transmission of COVID-19. This study was conducted in a trafficintensified area of Kathmandu valley, where vehicular movement represents one of the main sources of air pollution. Hence, this study was intended to quantify the concentration of particulate matter (PM<sub>2.5</sub>) for 11 hours of daytime from 23 April to 20 May 2020. It was also to evaluate the influences of lockdown on air quality. PM<sub>2.5</sub> was observed using HAZ-Dust, Environmental Particulate Air Monitor in the 18 different traffic sites of the Kathmandu valley. During the lockdown period, a substantially low mean concentration of PM<sub>2.5</sub> ranging from 3.69±1.78 µg/ m<sup>3</sup> to 7.58±3.98 µg/m<sup>3</sup> was recorded in Kathmandu valley, which reflected improved air quality due to the cessation of vehicular activities. Therefore, the study outcome suggests that controlling the existing vehicular activities and promoting energy-efficient vehicles like electric vehicles in specific locations in the city will improve air quality and benefit public health.</p> Pawan Kumar Neupane Sunil Babu Shrestha Dipesh Rupakheti Dev Raj Joshi Tista Prasai Joshi Copyright (c) 2022 Pawan Kumar Neupane, Sunil Babu Shrestha, Dipesh Rupakheti, Dev Raj Joshi, Tista Prasai Joshi 2022-12-31 2022-12-31 21 1 73 80 10.3126/njst.v21i1.49916 Comparative Adsorption Behavior of Malachite Green Dye onto Charred and Aminated Sal (Shorea robusta) Sawdust from Aqueous Solution <p>Chemically treated Sal sawdust was used to study the adsorption of Malachite Green (MG) dye from an aqueous solution. Raw Sal sawdust (RSSD) was charred and aminated. The surface functional groups of raw and modified adsorbents were determined by Fourier Transform Infrared Spectra (FTIR). The influence of pH on batch experiments, concentration and contact time for charred Sal sawdust (CSSD) and aminated Sal sawdust (ASSD) were investigated. The dye uptake was highest at a pH of 4, and adsorption was found to be 62.63 % and 92.15% for CSSD and ASSD, respectively, at an adsorbent dose of 0.025 g and agitation speed of 190 rotations per minute (rpm). The pertinency of Langmuir isotherm was tested, and the kinetic data was found best fitted for pseudo-second-order. The adsorption capacity of MG dye onto ASSD and CSSD was found to be 91.9 mg/g and 64 mg/g, correspondingly. This showed that ASSD is a more efficient adsorbent than CSSD for excluding MG dye from an aqueous solution.</p> Puspa Lal Homagai Sanjita Rayamajhi Dilli Dhami Ram Lal Shrestha Deval Prasad Bhattarai Copyright (c) 2022 2022-12-31 2022-12-31 21 1 81 90 10.3126/njst.v21i1.49917 Performance of Reinforced Concrete Shear Wall In Dual Structural System: A Review <p>A dual structural system consists of a momentresisting frame, and vertical reinforced concrete walls called shear walls. Shear walls used in tall buildings are generally located around elevator cores and stairwells. Many possibilities exist in a tall building regarding the location, shape, number, and arrangement of shear walls. Shear walls generally start at the foundation level and are continuous throughout the building height. Their thickness can be as low as 150mm in lowrise to medium-rise buildings or as high as 400mm in high-rise buildings. To establish an effective lateral force-resisting system, the shear walls are located in preferable positions in a structure that minimizes lateral displacements. The shear walls are situated in ideal locations to be symmetrical and torsional effects get reduced. Based on the comparison of various literature regarding the shear wall positions, the shear wall placement at the core or the corners of the structure symmetrically gives the best performance to reduce displacement and story drift. Also, lateral displacement diminishes when the shear wall’s thickness increases.</p> Rajan Suwal Aakarsha Khawas Copyright (c) 2022 2022-12-31 2022-12-31 21 1 91 100 10.3126/njst.v21i1.49918 A Review on Microbial Fuel Cell Performance for Energy Generation <p>Much work in a microbial fuel cell (MFC) is necessary in today’s context to meet an environmentfriendly and sustainable technology for alternative energy. A huge depletion in fossil fuel is going on rapidly. There may be high chance of a fuel crisis and global warming shortly. MFC is a promising technology in the field of energy production. MFC is a promising technology in the field of energy production. MFC operates with the degradation of different types of wastes by generating various by-products. Proper design and operation of MFC help to get optimum output. The performance of MFC depends on appropriate electrode materials, substrates, pH and type of microbes grown. In MFC, microbial oxidation of natural wastes occurs at ambient temperature. The generated reaction produces energy.</p> Sulochana Pradhan Jarina Joshi Copyright (c) 2022 2022-12-31 2022-12-31 21 1 101 106 10.3126/njst.v21i1.49919 A Broad Perspective on Cloud Integrated Flight Data Recorder <p>The history of air traffic, whether its about the safety or the qualitative inspection of the several sensors and interconnected mechanical parts, is well known. Hence, the efforts applied through the research and analysis of several engineers profoundly made the air traffic investigation safer and more comfortable. As a result,the flight investigation of whether the lost aircraft or the airplane’s found wreckage has become more secure and convenient than in the Past. The use of light and advanced materials, the development of excellent communication equipment, and the rapid development of the aviation sector have played a crucial role in increasing its safety and reach to the general public, and so do the several challenges associated with the aviation sector. As a result, there has been much research regarding the air traffic investigation with the help of advanced sensor and better software that can simulate and even predict the dangers provided by several parameters helping in the investigation and exploring better sides of safety. The accident can be prevented with the help of improvements provided based on accurate analysis of previous air accidents. In modern aircraft, there is a device called the Black Box which helps analyze and investigate. For example, after Malaysian flight MH370’s disappearance, the airline again felt to upgrade the black box to a new working standard of the cloud-based technology. Currently, there are many cloud storage services worldwide such as GOOGLE, APPLE, AMAZON, MICROSOFT etc. After this accident and similar previous aircraft disappearances from different parts of the world, researchers finally decided to test steaming to nearby air traffic services and storing flight data in remote cloud storage. This study attempts to compile the worldwide efforts in the cloud-integrated flight data recorder (CIFDR) field. This research primarily focuses on different ways of storing data on cloud-based technology. The different trend worldwide approaches and different means applied to test this system without hindering the associated safety of the data going through encryption and decryption. Recently there has been a proliferation of internet facilities in flight. Although it is still in its infancy phase, the flight data can be sent to remote servers by improving this technique. Many challenges in transmitting flight data in real-time need to be overcome before commercializing this technique.</p> Satish Chaudhary Aditya Pratap Singh Devender Sharma Copyright (c) 2022 2022-12-31 2022-12-31 21 1 107 120 10.3126/njst.v21i1.49920 Fall Armyworm: Current Status in Nepal, its Management and Way Forward <p>Fall armyworm (FAW), <em>Spodoptera frugiperda</em> (J. E. Smith) (Lepidoptera: Noctuidae), is an economically important invasive pest species primarily infesting maize. It is highly polyphagous and migratory in nature, posing a threat to several economically important crops. This pest has traveled a long journey from the American continent to Asia via Africa. This insect has inflicted substantial damage to Maize’s crop productivity of Maize in Nepal, since its introduction in May 2019 and has now become widespread from plain regions to hilly regions of the country. Therefore, this pest problem is considered a major issue for research and development in the country. The lessons from world research and development in the fall armyworm management could be adapted and used in Nepal after its proper validation. In order to identify the current status of fall armyworm in Nepal and the management of the insect species, we have discussed overviews on biology, ecology, origin and distribution pathway, management, and way forward, focusing on sustainable measures which could be useful for designing integrated pest management of fall armyworm in Nepal since knowledge gap is large.</p> Sushil Nyaupane Ram P Mainali Sagar Kafle Ajaya SR Bajracharya Copyright (c) 2022 Sushil Nyaupane, Ram P Mainali, Sagar Kafle, Ajaya SR Bajracharya 2022-12-31 2022-12-31 21 1 121 138 10.3126/njst.v21i1.49960 Editorial Message <p>N/A</p> Sunil Babu Shrestha Copyright (c) 2023 2023-01-08 2023-01-08 21 1