https://www.nepjol.info/index.php/BIBECHANA/issue/feed BIBECHANA 2020-01-14T12:42:36+00:00 Prof. Dr. Devendra Adhikari deven.bmhs@gmail.com Open Journal Systems <p>BIBECHANA: A multidisciplinary journal of Science, Technology and Mathematics is published by Department of Physics, Mahendra Morang A.M. College, Tribhuvan University, Biratnagar, Nepal. Full text articles available. BIBECHANA does <strong>not</strong> charge authors article processing charges, submission fees, or any other kind of fee.</p> https://www.nepjol.info/index.php/BIBECHANA/article/view/25504 Hydrophobicity of small alkane molecules (propane dimer) in solvents: a classical molecular dynamics study 2019-12-26T16:52:35+00:00 Bikash Panthi adksbdev@yahoo.com Nurapati Pantha devendra@mmamc.edu.np <p>Molecular Dynamics (MD) simulations of propane dimer in different solvents (water, acetonitrile and methanol) were performed by using CHARMM platform for modeling the solute and solvents. A series of Umbrella sampling MD simulations were carried out in each solvent separately and potential of mean force (PMFs) were calculated by using Weighted Histogram Analysis Method. Results show that two minima (contact minima and solvent separated minima) characterize the PMF of propane dimer in all three solvent environments. The contact minima are deeper and less sensitive to solvent environment for its position. However, significant effect in the position of second minima, solvent separated minima, was observed. Our study reveals that the interaction between propane dimer is softer in methanol and acetonitrile than in water.</p> <p>BIBECHANA 17 (2020) 1-12</p> <p>&nbsp;</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/23485 Bio-Synthesis of copper nanoparticles (CuNPs) using Garlic extract to investigate antibacterial activity 2019-12-26T11:44:26+00:00 Sharmila Pradhan Amatya amatyasharmila@yahoo.com Leela Pradhan Joshi adksbdev@yahoo.com <p>Bio-synthesis of metal nanoparticles (CuNPs) is regarded as one of the recently developed, economic and environmentally benign method. In the present investigation, Copper nanoparticles were synthesized reacting garlic (<em>Allium</em><em> sativum</em>) extract with Copper Sulphate (CuSO4∙5H2O) solution over magnetic stirrer at 80 °C for 1 hour. So-prepared CuNPs were studied by observing the color change at various time intervals.&nbsp; Further, the nanoparticles were characterized using UV-Visible spectroscopy, Energy Dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). The results of UV-Vis&nbsp;&nbsp; spectroscopy&nbsp;&nbsp; clearly showed presence of absorption peak at 595 nm which confirmed&nbsp;&nbsp; the&nbsp;&nbsp; formation&nbsp;&nbsp; of&nbsp;&nbsp; copper nanoparticles. Likewise, the EDX spectrum depicts the presence of optical band at 8 eV which is the characteristic peak of Copper consisting of 38.747 % by weight and FTIR spectra revealed presence of various phytochemicals possessing characteristic functional groups such as carbonyl and phenolic at the surface of CuNPs. Thus, natural products available in the garlic extract help in reduction and stabilization of Copper nanoparticles. &nbsp;The antibacterial activity of Copper nanoparticles was investigated against Gram +ve (<em>Staphylococcus aureus) </em>and Gram –ve bacteria<em> (</em><em>Escherichia coli)</em> using Agarwell diffusion method. The results of antibacterial test showed that CuNPs were found to be much sensitive towards Gram –ve bacteria compared to gram +ve bacteria.</p> <p>&nbsp;BIBECHANA 17 (2020) 12-18</p> <p>&nbsp;</p> <p>&nbsp;</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25208 Structure-activity relationship and MM2 energy minimized conformational analysis of quercetin and its derivatives in the DPPH• radical scavenging capacity 2019-12-26T11:45:42+00:00 Gan B Bajracharya ganbajracharya@yahoo.com Mohan Paudel paudelmohan2010@gmail.com Rajendra K. C. rajukc4777@gmail.com Sajan L. Shyaula shyaulasajan@gmail.com <p>Antioxidant activity of quercetin (<strong>1</strong>) and its derivatives (<strong>2</strong>-<strong>15</strong>) was evaluated by using DPPH assay and IC<sub>50</sub> values were calculated. Dihedral angles α of C3-C2-C1’-C6’ chain and β of O1-C2-C-1’-C2’ chain between AC and B rings of these flavones were determined by using MM2 energy minimized structures. Structure-activity relationship study revealed that quercetin (<strong>1</strong>), quercetin-5-methyl ether (<strong>2</strong>), quercetin-3’-methyl ether (<strong>3</strong>) and quercetin-3’,5-dimethyl ether (<strong>4</strong>) displaying a high antioxidant activity (IC<sub>50</sub> = 47.20-119.27 μM) possess similar dihedral angles (α 11.1-11.5º and β 6.3-6.6º). Mono- and/or di-methoxy substituent(s) at 3’ and 5 positions of the flavone are most suitable for the preservation of the antioxidant capacity while retaining conformational geometry.</p> <p>BIBECHANA 17 (2020) 19-26</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25599 Natural dyes as photo-sensitizer in solar cells 2019-12-26T11:38:24+00:00 Surendra Bikram Silwal adksbdev@yahoo.com Rameshwar Adhikari adksbdev@yahoo.com Prakash Lamichhane adksbdev@yahoo.com Netra Lal Bhandari adksbdev@yahoo.com <p>The objective of this research is to employ the natural dyes in dye-sensitized solar cell (DSSC). On account of eco-friendly, renewable, and non-hazardous properties of natural dyes over silicon, a semiconductor, photo-sensitizer in conventional solar cells, &nbsp;cyclohexane extract of <em>Terminalia alata</em>, a natural dye, was employed as photo-sensitizer. The photoanodes ZnO and 5% Al-doped ZnO for DSSCs were developed by spray pyrolysis. The X-ray diffraction (XRD) has shown hexagonal wurtzite structure of ZnO with lattice constants a = 3.2487 Å and b = 5.1518 Å having particle size 25.85 nm for ZnO and 33.17 nm for Al-doped ZnO. The DSSC properties such as solar conversion efficiency (η), short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) were found to be 0.31%, 2.10 mA/cm<sup>2</sup>, 0.73V, and 45% for ZnO photoanode and 0.37%, 2.25mA/cm<sup>2</sup>, 0.70 V, and 52.10% for 5% Al-doped photoanode respectively.</p> <p>BIBECHANA 17 (2020) 27-32</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/21741 Comparative studies on the electronic transport in magnetically quantized low band gap semiconductor system 2019-12-26T11:42:04+00:00 S Shrestha sanju12np@yahoo.com C K Sarkar adksbdev@yahoo.com <p>The Q1D system formed by magnetically confined system is attracting attention of researchers in device application because it is capable of over-looking the various techniques of fabrication difficulties and defects created by such fabrication techniques. In the presence of a high magnetic field, the transverse component of the energy dispersion relation gets quantized into various equally spaced energy levels called Landau levels and the motion of the carriers is completely restricted. However, the longitudinal component along the field is still free to move. The mobility of such system is enhanced when a low effective mass semiconductors n-HgCdTe (Mercury Cadmium Telluride) is used. The band structure of n-HgCdTe is found to be nonparabolic due to its low band gap according to Kane [Phadke and Sharma, 1975]. Recent publications, based on experimental verifications of transport coefficient of n-HgCdTe of Chen and Sher [Chen and Sher, 1982] show that the band structure of Mercury Cadmium Telluride (MCT) is more hyperbolic in nature rather than nonparabolic. The author has compared the effect of band structures on the various transport properties of MCT such as mobility, Seebeck coefficient, thermal conductivity, figure of merit (Z) etc. The figure of merit is a very important property of a material to be used in thermoelectric devices, such as cooler, refrigerator etc. The product of Z and temperature i.e. (ZT),&nbsp;a dimensionless quantity is found to be maximum for parabolic band structure and is followed by nonparabolic and hyperbolic band structures for all ranges of variation of temperature as well as magnetic field. Taking the hyperbolic band structure of MCT, the effect of high and low temperature scattering mechanisms on ZT is also observed.</p> <p>BIBECHANA 17 (2020) 34-41</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25839 Study of dust color temperature and visual extinction distribution of a far infrared cavity at 60 and 100 µm IRAS map around the AGB star at galactic latitude 8.6⁰ 2019-12-26T12:12:03+00:00 A K Gautam arjungautamnpj@gmail.com B Aryal adksbdev@yahoo.com <p>The dust-grain structure in the far infrared region under IRAS (Infrared Astronomical Satellite) Survey was studied using sky view virtual observatory. In order to find the possible far infrared cavity, we used SIMBAD database. In this paper, we discuss about the dusty environment of a far infrared cavity around the AGB star located at R.A. (J2000) =01<sup>h</sup> 41<sup>m</sup> 01<sup>s</sup> and Dec (J2000) = 71<sup>o</sup> 04’ 00” lying within far infrared loop G125+09&nbsp; in the far infrared IRAS maps. A cavity like structure (major diameter ∼ 2.55 pc &amp; minor diameter ∼ 0.77 pc) is found to lie at R.A. (J2000)= 01<sup>h</sup> 46<sup>m</sup> 57.2<sup>s</sup> and DEC (J2000)= 71<sup>o</sup> 24’ 57.1”, located at a distance ∼ 220 pc from the star. We studied the distribution of flux density, dust color temperature, dust mass, inclination angle, visual extinction and FIR spectral distribution of the cavity. We further studied the distribution of Planck function along extension and compression. The dust color temperature is found to lie in the range (19.7±0.65) K to 21.1±0.35) K which shows the cavity is isolated and stable. Product of visual extinction and dust color temperature is found to be less than one. A possible explanation of the results will be discussed.</p> <p>BIBECHANA 17 (2020) 42-49</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25870 Constant velocity pulling and unfolding of thyroid hormone receptor by steered molecular dynamics 2019-12-26T12:15:27+00:00 Tika Ram Lamichhane tikaramlamichhane@yahoo.com Hari Prasad Lamichhane hlamichhane1@gmail.com <p>Unfolding pathways of T3 liganded thyroid hormone receptor (THRT3) can be studied by using the protocols of steered molecular dynamics (SMD). Theory of constant velocity pulling has been implemented to the structure of THRT3 in a neutral water-ion solution equilibrated up to 20 ns. The globular form of THRT3 is completely unfolded extending N-C termini from 38 Å to 876 Å at a constant speed of 0.1 Å/ps by means of 8.5 ns long SMD simulations. The peak force measured in the intermediate conformations is related to a burst of backbone H-bonds among a-helices and b-hairpins. With decrease in H-bonds, electrostatic energy increases by losing gradually the secondary structure and separating a and b-strands in solution. The force at the end (t &gt; 8.5 ns) increases steeply with the large increase in bond-angle and bond-length potentials when the system becomes completely unfolded. The hydrophobic ligand binding domain (LBD) of THR-b with load bearing H-bonds protects T3 from water attack.&nbsp; Even after complete unfolding of THR-b LBD, the position of T3 is not deviated more than 2.5 Å and a large number of water molecules remain in the surrounding of this domain area. This is a strong evidence for the mechanochemical stability of a receptor protein’s LBD towards hormone activated gene expressions followed by ligand binding and dissociation<strong>.</strong></p> <p><strong>BIBECHANA 17 (2020) 50-57</strong></p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25598 Composite of lampblack and printer toner powder as a low-cost counter electrode material for dye-sensitized solar cells 2019-12-26T16:47:52+00:00 Prakash Joshi joship7@gmail.com Umesh Lawaju umeshlawaju03@gmail.com Binod B.K. binodb936@gmail.com <p>Lampblack prepared by using a traditional mustard oil lamp was mixed with printer toner in the ratio of 1:1 by weight and the composite was used as a low-cost catalyst for the reduction of tri-iodide ions in dye-sensitized solar cells (DSCs). The X-ray diffraction (XRD) of the lampblack showed that the lampblack contains a carbonaceous material of graphitic form. The adhesion test of the composite film on the counter electrode (CE) of the DSC showed that the composite film is firmly attached on the CE. The DSC with CE based on the composite of lampblack and printer toner yielded the overall light to electricity conversion efficiency of 3.20 % compared with 4.18 % efficiency of the DSC with CE based on platinum when the solar cells were tested in the simulated light of 100 mW/cm<sup>2</sup>.</p> <p>BIBECHANA 17 (2020) 58-66</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25236 The Physicochemical analysis and Phytochemical screening of some medicinal plants of Letang Municipality of Morang district, Nepal 2019-12-26T12:20:23+00:00 Narendra Kumar Chaudhary chem_narendra@yahoo.com Rijan Ojha reasonojha55@gmail.com Tilak Prasad Gautam tilakg673@gmail.com <p>Ethnobotany gives the basic idea about the medicinal properties of plants. Identification of active compounds of the medicinal plants and their standardization is essential for the production of new drugs. In the present work, different parts of the five medicinal plants (<em>Curcuma caesia, Costus speciosus, Drymaria cordata, Leea macrophylla, Plumbago zeylanica</em>) were washed, air dried and crushed. Three different extracts of each powdered material were prepared and standard phytochemical analysis procedure was followed for the analysis of physicochemical properties of plants and the identification of active chemical constituents. Among 5 plants, the highest moisture content (14.83%) was found in <em>Plumbago zeylanica, </em>higher total ash (9.22%) and acid insoluble ash (4.43%) were observed in <em>Cucurma caesia</em>. Phytochemical analysis revealed the presence of 12 varieties of bioactive chemicals in the 5 different plants. The plants of the area have great diversity of phytochemicals of numerous medicinal properties. In conclusions, these five important medicinal plants could be useful for the people of the locality to cure several diseases as well as to generate the source of income.</p> <p>BIBECHANA 17 (2020) 67-74</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26503 Effective action approach to the Leggett's mode in two-gap superconductors 2019-12-26T12:23:43+00:00 Bal Ram Ghimire balramghimire@gmail.com Shanker P Chimouriya adksbdev@yahoo.com Basant Gyawali devendra.physics@yahoo.com <p>When electrons of two electronic bands participate in superconducting phenomena, it is said to be two gap superconductor. There are two set of cooper pairs in different energy gap with different energy. The observation of Leggett’s mode in two band superconductor provides an additional information about superconductor. By using the effective action, the thermodynamic potential in the case of neutral and charged two gap superconductor are calculated.&nbsp; Using phase dependent action, we investigate a collective excitation (Leggett’s mode) corresponding to small fluctuations of the relative phase of two condensates in two band superconductor. We consider the possibility of observing Leggett’s mode in MgB<sub>2</sub> superconductor and conclude that for the known values of two band model parameters for MgB<sub>2</sub>, Leggett’s mode rises above the two particle threshold.</p> <p>BIBECHANA 17 (2020) 74-79</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26507 Spectral analysis of aerosol optical depth over aeronet sites of Nepal 2019-12-26T12:26:46+00:00 Aashma Acharya adksbdev@yahoo.com Binod Adhikari binod.adhi@gmail.com Pratik Bhattarai devendra.physics@yahoo.com Gopal Jha adksbdev@yahoo.com Shambhu Acharya devendra.physics@yahoo.com Ritesh Shah adksbdev@yahoo.com <p>The suspended particle aerosols especially anthropogenic are recognized to have degradation in the quality of the atmosphere and one of the factors to cause uncertainty in climate. In this paper, we have investigated the trend of the parameter ‘Aerosol Optical depth’ and by application of spectral based wavelet analysis; we extracted spatial and temporal variation over the selected AERONET sites of Nepal. We have taken the site Kyanjin_gompa, Lumbini, Pokhara and Kathmandu under the consideration of our study because of their geographical variability which is a significant factor for causing variation in local as well as global circulation of aerosols. As per data retrieved from Ground-Based remote sensing system for the year 2018 over the site Kyanjin gompa, Lumbini and Pokhara and for the year 2016 over the Kathmandu, we extracted the periodicity and frequency of the variation in AOD for each site by the application of continuous wavelet analysis on AOD at three different wavelengths. On reviewing the previous studies, it is seen that the area lying at the Indo-Gangetic plain exhibit high aerosol loading in comparison with the Himalayan foothills and central Himalayas of Nepal. We found not only the higher aerosol loading in atmosphere over site Lumbini but also higher periodicity. Likewise, we also found Pokhara as highly polluted as Lumbini. The investigation of data records over the site Kathmandu has shown increment in aerosol loading in the year 2016 compared with previous years.</p> <p>BIBECHANA 17 (2020) 80-88</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/25201 Chemical profiling and antioxidant activities of essential oil from rhizomes of Acorus calamus L. 2019-12-26T12:30:00+00:00 Sumnath Khanal khanalsn187@gmail.com Devi Prasad Bhandari dpbhandari81@gmail.com Laxman Bhandari bhandarisuman411@gmail.com Achyut Adhikari achyutraj05@gmail.com <p><strong>Background and Aims: </strong><em>Acorus calamus</em> L. is an indigenous herb in Nepal. It belongs to family Acoraceae and grows in wet land with scented rhizomes. It is also known as Sweet flag in English and commonly as Bojho in Nepal. The present investigation reveals the chemical compositions and antioxidant activity of rhizome essential oil of <em>A. calamus</em>. <strong>Methods: </strong>Essential oil of rhizomes of <em>Acorus calamus</em> L. from Kaski district, Nepal was extracted by hydrodistillation method and volatile constituents were analyzed Gas chromatography-Mass spectrometry. The antioxidant potential of essential oil was analyzed by 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) scavenging assay<strong>. Results: </strong>A GC-MS analysis revealed the presence of <em>β</em>-asarone (22.38%), <em>α</em>-asarone (14.97%), 1-(4,6-dimethoxy-2,3-dimethylphenyl ethanone (14.24%), Isoelemicin (5.68%), cis-Methylisoeugenol (4.26%), <em>α</em>-calacorene (4.16%), and other 20 minor components. From DPPH assay, half maximal inhibitory concentration (IC<sub>50</sub>) value of essential oil was found to be 108.71 µg/mL.<strong> Conclusions: </strong>These findings have strengthened the <em>A. calamus</em> L. is good source of compounds like <em>β</em>-asarone, <em>α</em>-asarone and can be used as potential antioxidants.</p> <p>BIBECHANA 17 (2020) 89-95</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26521 Study of damage profiles and energy calculation of arsenic ions during ion implantation on Germanium 2019-12-26T12:33:00+00:00 K Giri karangiri575@gmail.com B Kandel adksbdev@yahoo.com <p>Computational calculation of energy loss and damage profiles when implanted by arsenic ions on amorphous germanium during ion implantation had been carried out. The required energies for doping of arsenic ion on germanium, in order to obtain maximum damage at 600 Å, were calculated using SRIM. These ions when implanted on germanium causes the production of germanium recoils, vacancy-interstitial pairs, and phonons during the collision process. For 140 keV arsenic ion, the energy consumption for ionization, phonon production and vacancies creation are 39.634 keV (28.31% of incident energy), 90.888 keV (64.92% of incident energy) and 9.478 keV (6.77% of incident energy), respectively. The amount of target displacement, replacement collisions and vacancies were also evaluated. Doping of arsenic ions on germanium also revealed that the energy loss due to nuclear stopping was greater than electronic stopping. Significantly, surface hardness and electrical conductivity on germanium cannot be improved with calculated energies.</p> <p>BIBECHANA 17 (2020) 96-103</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/24674 Phytoconstituents and biological analysis of Acorus calamus rhizome of Sindhupalchowk District, Nepal 2019-12-26T12:35:07+00:00 Shanta Pokhrel shantabhattarai2014@gmail.com Kalpana Chaulagain kalpanachaulagain7@gmail.com <p>Phytochemical and biological activities of methanolic and hexane extract of <em>Acorus calamus</em> rhizome were carried out<em>.</em> Phytochemical analysis showed the presence of flavonoid, glycoside, saponin, resin and carbohydrates which are responsible for the antibacterial activities. The antibacterial potential was studied against <em>Staphylococcus aureus</em> (gram positive bacteria) and <em>Escherichia coli,</em> <em>Salmonella typhi</em> (gram negative bacteria) using Agar Well Diffusion Method. The activity was shown by both methanolic and hexane extract of <em>Acorus calamus</em> rhizome against both Gram positive and Gram negative bacteria. Antioxidant activity of methanolic extract was evaluated by 2, 2-diphenyl-1-picryl hydrazyl (DPPH) free radical scavenging activity showed potent antioxidant activities with IC<sub>50</sub> value 3.74 μg/mL slightly higher than standard ascorbic acid (IC<sub>50</sub> = 3.56 μg/mL).</p> <p>BIBECHANA 17 (2020) 104-109</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/24341 On Ricci solitons in LP-Sasakian manifolds 2019-12-26T12:46:32+00:00 Riddhi Jung Shah shahriddhijung@yahoo.com <p>In this paper we study Ricci solitons in Lorentzian para-Sasakian manifolds. It is proved that the Ricci soliton in a (2n+1)-dimensinal LP-Sasakian manifold is shrinking. It is also shown that Ricci solitons in an LP-Sasakian manifold satisfying the derivation conditions R(ξ,X).W<sub>2</sub> =0,W<sub>2</sub> (ξ,X).W<sub>4</sub> =0 and W<sub>4 </sub>(ξ,X).W<sub>2</sub>=0 are shrinking but are steady for the condition W<sub>2</sub> (ξ,X).S=0. Finally, we give an example of 3-dimensional LP-Sasakian manifold and prove that the Ricci soliton is expanding and shrinking in this manifold.</p> <p>BIBECHANA 17 (2020) 110-116</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26582 Spatial orientation of galaxies in supercluster S[227+006+0078] 2020-01-14T12:42:36+00:00 Janak Ratna Malla Janak_malla@yahoo.com Walter Saurer adksbdev@yahoo.com Binil Aryal aryalbinil@gmail.com <p>We present a study of spin vector orientation of 1218 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S [227+006+0078] having redshift 0.07 to 0.09. The database of these galaxies is taken from SDSS (Sloan Digital Sky Survey) 7<sup>th</sup> and 9<sup>th</sup> data release. We have converted two dimensional data to three dimensional by Godlowskian Transformation using position angle-inclination angle method. We intend to find non-random effects in the spatial orientation of galaxies in the Supercluster.&nbsp; No preferred alignment of angular momentum vectors is noticed, supporting Hierarchy model of galaxy formation.</p> <p>BIBECHANA 17 (2020) 117-122</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26249 Variation of Total Electron Content (TEC) in the Quite and Disturbed days and their correlation with Geomagnetic Parameters of Lamjung Station in the year of 2015 2019-12-26T16:05:28+00:00 Basu Dev Ghimire basu.ghimire99@gmail.com Narayan Prasad Chapagain adksbdev@yahoo.com Vardhan Basnet deven.physics@yahoo.com Karan Bhatta adksbdev@yahoo.com Balaram Khadka adksbdev@yahoo.com <p>Total Electron content is measured using a dual frequency GPS receiver in Lamgung (LMJG) Station located at 84.57° longitude and 28.17° latitude of the year 2015 as it is considered as geo-magnetically active year. In this study, diurnal variation of VTEC has been studied separately for quiet and disturbed days and, for the effective study of the case the PRN wise data of VTEC have been also used. The maximum VTEC is seen from 0700 LT to 1100 LT (LT=UT+5.45). PRN wise VTEC is studied taking the lower bound (LB) and upper bound (UB). The correlation of VTEC with Dst index, Kp index and Solar flux have been studied. Positive correlation has been found in disturbed days with Kp index and solar flux but negative correlation with Dst index. Dst index shows positive correlation in quiet days but Kp index shows negative correlation.</p> <p>BIBECHANA 17(2020) 123-132</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26869 Improvement of hydrophilicity of polyamide using atmospheric pressure plasma jet 2019-12-26T16:11:17+00:00 H B Baniya hombaniya@gmail.com R P Guragain adksbdev@yahoo.com B Baniya adksbdev@yahoo.com G Qin deven.bmhs@gmail.com D P Subedi adksbdev@yahoo.com <p>Atmospheric Pressure Plasma Jet (APPJ) has many applications in material processing such as surface modification and biomedical material processing. APPJ has been generated by a high voltage power supply (0-20 KV) at an operating frequency of (20-30) 23 kHz. This paper reports the generation and characterization of APPJ in Argon environment and its application in the surface modification of polymeric materials. The discharge has been characterized by optical and electrical methods. In order to characterize the plasma jet, its electron temperature and electron density has been determined by optical emissions spectroscopy. The surface properties of the untreated and plasma treated Polyamide (PA) samples were characterized by contact angle measurement and surface energy analysis.</p> <p>BIBECHANA 17 (2020) 133-138</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26877 Reassessments of thermo-physical properties of Si-Ti melt at different temperatures 2019-12-27T06:29:45+00:00 S K Yadav deven.bmhs@gmail.com U Mehta adksbdev@yahoo.com R K Gohivar adksbdev@yahoo.com A Dhungana adksbdev@yahoo.com R P Koirala adksbdev@yahoo.com D Adhikari adksbdev@yahoo.com <p>The compositional dependence of thermo-physical properties of Si-Ti liquid alloy has been reassessed using different modeling equations at temperatures 2000 K, 2400 K and 2473 K. The thermodynamic and structural properties of the system have been computed in the frame work of quasi-lattice test. The extent of surface segregation and surface tension of the liquid mixture have been computed using Butler’s equations at afore mentioned temperatures. The results so obtained have been compared with the available literature database. Theoretical investigations shows that the compound forming tendency of the system gradually decreases at elevated temperatures and hence it shows ideal behaviours, as expected.</p> <p>BIBECHANA 17 (2020) 146-153</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement## https://www.nepjol.info/index.php/BIBECHANA/article/view/26867 Conventional to slow muon microscopy – a review 2019-12-26T16:34:38+00:00 Amba Datt Pant adksbdev@yahoo.com <p>Because of special characteristics (fully spin polarized and asymmetric decay to positron), muon acts as sensitive probe to study the local electronic and dynamics of materials. The muon of energy MeV or high, conventional muon, are used to study bulk properties of the materials. For the study of nanoscience, slow muon (20 eV - 30 keV) muon with low energy spread are essential that leads to development of slow muon microscopy. Introduction to muon microscopy, application of conventional muons and need of slow muon beam along with future prospects are briefly discussed.&nbsp;</p> <p>BIBECHANA 17 (2020) 139-145</p> 2020-01-01T00:00:00+00:00 ##submission.copyrightStatement##