BIBECHANA https://www.nepjol.info/index.php/BIBECHANA <p>BIBECHANA: A multidisciplinary journal of Science, Technology, and Mathematics is published by the Department of Physics, Mahendra Morang A.M. College, Tribhuvan University, Biratnagar, Nepal. Full-text articles are available. BIBECHANA does <strong>not</strong> charge authors article processing charges, submission fees, or any other kind of fee.</p> <p>Articles in BIBECHANA are published only online. The printed version (hard copy) of the journal is not available.&nbsp;&nbsp;</p> Department of Physics, Mahendra Morang A.M. College, Tribhuvan University, Biratnagar, Nepal en-US BIBECHANA 2091-0762 Investigation of some basic thermodynamic properties of Na-K alloy https://www.nepjol.info/index.php/BIBECHANA/article/view/31628 <p>Investigation of thermodynamic of liquid binary alloys using pseudopotential theory is reported. The potential suggested by Fiolhais <em>et al.</em> with its individual parameters is used for the entire calculation. A transferability of the potential from the solid to liquid medium is achieved for the presently reported binary alloy. The internal energy components, Helmholtz free energy, entropy, and total energy at various proportions of the participating alkali metals are included in the study. The comparison with the other data has been shown in the present article. Exchange and correlation effect is also tested with the help of various local field correction functions.</p> <p>BIBECHANA 18 (2) (2021) 1-8</p> Rajesh C Malan Aditya M Vora Copyright (c) 2021 Rajesh C Malan, Aditya M Vora 2021-01-03 2021-01-03 18 2 1 8 10.3126/bibechana.v18i2.31628 Visualization, formulation and intuitive explanation of iterative methods for transient analysis of series RLC circuit https://www.nepjol.info/index.php/BIBECHANA/article/view/31208 <p>The time varying currents and voltages resulting from the sudden application of sources usually due to switching are transients. An RLC circuit is an electrical circuit consisting of a resistor, an inductor, and a capacitor, connected in series or in parallel. The transient response is dependent on the value of the different characteristics of damping factor (i.e., over damped, critically damped and under damped). We have computed the numerical solutions of second order differential equation with initial value problem (IVP) by using Explicit (Forward) Euler method, Third order Runge-Kutta (RK3) methods and Butchers fifth order Runge-Kutta (BRK5). The observation compares this numerical solution of ODEs obtained by above-mentioned methods among them with necessary visualization and analysis of the error. These iterative methods will be extended and implement to analyze the transient analysis of an RLC circuit. &nbsp;We have examined the superiority of those methods over one another. The Butchers fifth order Runge-Kutta (BRK5) method is found to be the best numerical technique to solve the transient analysis due to its high accuracy of approximations. Moreover, we consider the possibility of discussion and analyze above mentioned iterative methods in the cases of different characteristics of damping factor.</p> <p>BIBECHANA 18 (2) (2021) 9-17</p> <p>&nbsp;</p> Jeevan Kafle Bhogendra Kumar Thakur Indra Bahadur Bhandari Copyright (c) 2021 Jeevan Kafle, Bhogendra Kumar Thakur, Indra Bahadur Bhandari 2021-02-02 2021-02-02 18 2 9 17 10.3126/bibechana.v18i2.31208 Phytochemical analysis, antioxidant and antibacterial efficacy of methanol and hexane extract of Centella asiatica https://www.nepjol.info/index.php/BIBECHANA/article/view/30760 <p><em>Centella asiatica </em>is well known for its anti-inflammatory, anticancer, antioxidant, antimicrobial, analgesic, diuretic properties. Its hexane and methanol extracts were screened for the presence of phytoconstituents as well as their antibacterial and antioxidant activity. The phytochemical screening showed the presence of carbohydrate, glycosides, flavonoids, phenolic compound, alkaloids, and saponin. The methanol extract showed more effective antibacterial activity against <em>salmonella typhi</em>. Antioxidant activity of methanol extract was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (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> = 2.576 μg/mL). The present study indicates that the tested plant can be an important source of antibacterial agents and recommends that the active phytoconstituents be isolated, identified, and screened individually for activities and also subjected further for <em>in vivo</em> and toxicological studies.</p> <p>BIBECHANA 18 (2) (2021) 18-25</p> Shanta Pokhrel Prabha Neupane Copyright (c) 2021 Shanta Pokhrel, Prabha Neupane 2021-02-09 2021-02-09 18 2 18 25 10.3126/bibechana.v18i2.30760 Study of two-photon absorption and optical limiting https://www.nepjol.info/index.php/BIBECHANA/article/view/34838 <p>Simultaneous absorption of two photons of identical or different frequencies to excite a system that is atom or molecule from the ground state to excited state has great importance. It has an important role as a spectroscopic tool for determining the positions of energy levels that are not connected to the atomic ground state by the one-photon transition. In this work, experimental study of two-photon absorption of fused silica, quartz crystal, and metal halides and optical limiters based on the semiconductors are studied. It was investigated that two photons absorption depletes the transmitted beam but carrier defocusing spreads the beam in space and hence density is reduced. It was realized that limiters with thin samples have low dynamic range and fluency is high on the damage-prone surface and irreversible damage occurs. Some Semiconductors with high nonlinearity are found to be useful materials for optical limiters to protect devices like sensors.</p> <p>BIBECHANA 18 (2) (2021) 26-31</p> Bal Ram Ghimire Copyright (c) 2021 Bal Ram Ghimire 2021-02-09 2021-02-09 18 2 26 31 10.3126/bibechana.v18i2.34838 Variability of b-value before and after the Gorkha earthquake in the Central Himalaya and Vicinity https://www.nepjol.info/index.php/BIBECHANA/article/view/31207 <p>This study computes the b-value of Gutenberg-Richter relation associated with the 25 April 2015 Gorkha earthquake and its aftershock sequences. For this the homogeneous catalogue of 769 earthquakes that occurred in the Himalayan compressed belt and its vicinity was analyzed by three different approaches. The minimum b-values 0.60±0.07 and 0.63±0.06 were observed for windows containing Gorkha earthquake. For time window before Gorkha earthquake, the b-value was noted as 0.89±0.12. It was noted 0.81±0.04 for time window between Gorkha earthquake and Dolakha earthquake and 0.78±0.08 for time window after Dolakha earthquake. The results revealed the fact that b-value starts to decrease for strong earthquake. About 17% jumps of the b value were observed within 17 days between Gorkha earthquake and its largest aftershock, the Dolakha earthquake. The b-value 1.16±0.09 was obtained for the depth range of 0-10 km, 0.89±0.4 for the depth range 10-20 km and 0.65±0.08 for the depth range of 20-30 km. The results strongly support the global trends of decreasing b-value with depth in the continental crust and subduction zones. The low b-value patch observed in the west of Gorkha from contour map depicts the region as the potential zone of future strong seismic activity.</p> <p>BIBECHANA 18 (2) (2021) 32-42</p> Ram Krishna Tiwari Harihar Paudyal Copyright (c) 2021 Ram Krishna Tiwari, Harihar Paudyal 2021-02-11 2021-02-11 18 2 32 42 10.3126/bibechana.v18i2.31207 Study of star formation rate and metallicity of the low redshift (z < 0.02) dwarf galaxies https://www.nepjol.info/index.php/BIBECHANA/article/view/34067 <p>In this paper, we have presented an analysis of emission lines from two dwarf galaxies. We analyzed the strongest emission lines of wavelength ranging from 4100 Å to 6700 Å.&nbsp; Among these emission lines, Hα and OIII have the highest intensities with 113.09×10<sup>-17</sup> erg/s/cm<sup>2</sup>/Å and 142.12×10<sup>-17</sup> erg/s/cm<sup>2</sup>/Å in the galaxies SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3, respectively. The Gaussian fit carried out in these emission lines showed the perfect fits with regression coefficient greater than 98 %, and full width half maximum (FWHM) of less than 4 Å. The line ratios calculated between Hα and Hβ for SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3 were 2.78 and 2.85, respectively, suggesting that the galaxies are starburst galaxies. The measurement of the Hα line from both galaxies was then used to assess the rate of star formation. The star formation rate of the galaxies SDSSJ222726.64+120539.8 and SDSSJ162753.47+482529.3 was found to be 0.010 <em>M</em><sub>☉</sub>year<sup>-1 </sup>and 0.016 <em>M</em><sub>☉</sub>year<sup>-1</sup>, respectively, indicating a low rate of star formation, and the emission line metallicity was derived using the Hα and NII line, which were measured to be 8.23 dex and 8.70 dex, respectively.</p> <p>BIBECHANA 18 (2) (2021) 43-49</p> S. P. Gautam A. Silwal N. Lamichhane A. K. Jha B. Aryal Copyright (c) 2021 Sujan Prasad Gautam, Ashok Silwal, Nishan Lamichhane, Ajay Kumar Jha, Binil Aryal 2021-02-23 2021-02-23 18 2 43 49 10.3126/bibechana.v18i2.34067 Use of geometric Brownian motion to forecast stock market scenario using post covid-19 NEPSE index https://www.nepjol.info/index.php/BIBECHANA/article/view/31180 <p>Stock market is one of the fields where the randomness is prominent factor to be considered. Although many stochastic process deals which the randomness found in nature through the interdisciplinary subject like Econophysics, many of them exhibits cumbersome trends. So, Geometric Brownian motion (GBM) is used to analyze the market scenario of Nepal on the basis of the parameter; NEPSE Index along with the prediction of indices through python programming platform. Python simulation was carried out to check the consistency by implying it to the stable market timeline 2003/2004. And after the verification of the model proposed in the stable market year, the model (GBM) is employed to the unstable timeline; pandemic situation by COVID-19 in 2020. Mapping of Nepal stock market through GBM was found to be consistent with the standard forecasting accuracy making GBM one of the flexible and consistent to predict stock market scenario of Nepal accounting the random nature.</p> <p>BIBECHANA 18 (2) (2021) 50-60</p> Prabin Thapa Binil Aryal Copyright (c) 2021 Prabin Thapa, Binil Aryal 2021-02-25 2021-02-25 18 2 50 60 10.3126/bibechana.v18i2.31180 Radon study around earthquake affected areas of Nepal https://www.nepjol.info/index.php/BIBECHANA/article/view/29840 <p>Indoor radon concentrations were measured in dwellings of the earthquake-affected areas of Kathmandu valley, Gorkha, and Sindhupalchowk districts of Nepal using passive radon dosimeter LR115, a Solid State Nuclear Track Detector, SSNTD. The radon concentrations in dwellings of Kathmandu valley ranged from 11±6 Bq/m<sup>3</sup> to 135±26 Bq/m<sup>3 </sup>with a mean of 67.63 Bq/m<sup>3</sup>. For&nbsp; Gorkha, it ranged from 18±7 Bq/m<sup>3 </sup>to 363±65 Bq/m<sup>3 </sup>with an average of 104.64 Bq/m<sup>3 </sup>while minimum, maximum and average radon concentrations for Sindhupalchowk were 14±6 Bq/m<sup>3</sup>, 397±71 Bq/m<sup>3,&nbsp;</sup>and 78.46 Bq/m<sup>3</sup> respectively. The average annual effective dose to the inhabitants of Kathmandu valley, Gorkha, and Sindhupalchowk districts was calculated as 1.46 mSv/y, 2.26 mSv/y, and 1.69 mSv/y respectively. These annual doses were well below the action level of 10 mSv/y recommended by the International Commission on Radiological Protection which implies no significant radiological health hazards. Also, Excess Lifetime Cancer Risk and Lungs Cancer Cases per year per million people were determined.</p> <p>BIBECHANA 18 (2) (2021) 61-67</p> Bipin Rijal Nigam S. Silwal Govinda Chaudhary Pitamber Shrestha Buddha R. Shah Copyright (c) 2021 Buddha Ram Shah, Bipin Rijal, Nigam Singh Silwal, Govinda Chaudhary, Pitamber Shrestha 2021-03-13 2021-03-13 18 2 61 67 10.3126/bibechana.v18i2.29840 Electronic and magnetic properties of defected MoS2 monolayer https://www.nepjol.info/index.php/BIBECHANA/article/view/33905 <p>It is interesting to understand the effect of defects in 2D materials because vacancy defects in 2D materials have novel electronic and magnetic properties. In this work, we studied electronic and magnetic properties of 1S vacancy defect (1S<sub>v</sub>-MoS<sub>2</sub>), 2S vacancy defects (2S<sub>v</sub>-MoS<sub>2</sub>), 1Mo vacancy defect (Mo<sub>v</sub>-MoS<sub>2</sub>), and (1Mo &amp; 1S) vacancy defects ((Mo-S)<sub>v</sub>-MoS<sub>2</sub>) in 2D MoS<sub>2 </sub>material by first-principles calculations within spin-polarized density functional theory (DFT) method. To understand the electronic properties of materials, we have analyzed band structures and DOS calculations and found that 1S<sub>v</sub>-MoS<sub>2 </sub>&amp; 2S<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have semiconducting nature. This is because, 1S<sub>v</sub>-MoS<sub>2 </sub>&amp; 2S<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials open a small energy band gap of values 0.68 eV &amp; 0.54 eV respectively in band structures. But, in Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials, energy bands around the Fermi level mix with the orbital’s of Mo and S atoms. As a result, bands are split and raised around and above the Fermi energy level. Therefore, Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have metallic nature. We found that MoS<sub>2</sub>, 1S<sub>v</sub>-MoS<sub>2 </sub>&amp; 2S<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have non-magnetic properties, and Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have magnetic properties because magnetic moment of MoS<sub>2</sub>, 1S<sub>v</sub>-MoS<sub>2 </sub>&amp; 2S<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have 0.00 µ<sub>B</sub>/cell value and Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials have 2.72 µ<sub>B</sub>/cell &amp; 0.99 µ<sub>B</sub>/cell &nbsp;respectively. Therefore, non-magnetic MoS<sub>2 </sub>changes to magnetic Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials due to Mo and (1Mo &amp; 1S) vacancy defects.&nbsp; The magnetic moment obtained in Mo<sub>v</sub>-MoS<sub>2 </sub>&amp; (Mo-S)<sub>v</sub>-MoS<sub>2</sub>&nbsp;materials due to the distribution of up and down spins in 4p, 4d &amp; 5s orbitals of &nbsp;Mo atoms and 3s &amp; 3p orbitals of S atoms in structures. The significant values of the magnetic moment are given by distributed spins in 4d orbital of Mo atoms and 3p orbital of S atoms.</p> <p>BIBECHANA 18 (2) (2021) 68-79</p> <p>&nbsp;</p> Hari Krishna Neupane Narayan Prasad Adhikari Copyright (c) 2021 Hari Krishna Neupane, Narayan Prasad Adhikari 2021-04-17 2021-04-17 18 2 68 79 10.3126/bibechana.v18i2.33905 Morphological analysis of Cu substituted Ni\Zn in Ni-Zn ferrites https://www.nepjol.info/index.php/BIBECHANA/article/view/34383 <p>Cu substituted Ni in Ni<sub>0.5-x</sub>Cu<sub>x</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>(x = 0, 0.05, 0.1, 0.15 and 0.2) samples and Cu substituted Zn in Ni<sub>0.5</sub>Zn<sub>0.5−x</sub>Cu<sub>x</sub>Fe<sub>2</sub>O<sub>4</sub> (x = 0, 0.05, 0.1, 0.15 and 0.2) is synthesized using the sol-gel auto-combustion process. Recently, we have carried out their structural analysis using XRD and FTIR and found a cubic spinel structure. In this paper, we have studied their morphological and compositional structure with the help of a Scanning Electron Microscope (SEM) attached with an Energy Dispersive Spectrometer (EDS). The comparative study shows that the grain size of Cu substituted Ni is greater than Cu substituted Zn in Ni-Zn ferrite. These smaller grain-sized ferrites are preferred for many microstructural applications. Depending on the available magnetic field, sintering temperature, and atmosphere, they can have different nucleation, and hence their application mode is different. They can have a critical concentration that can tune their properties. The EDS attached with the SEM confirmed the proper composition of samples.</p> <p>BIBECHANA 18 (2) (2020) 80-86</p> D. Parajuli K. Samatha Copyright (c) 2021 D. Parajuli 2021-05-06 2021-05-06 18 2 80 86 10.3126/bibechana.v18i2.34383 GPS TEC Scintillations and TEC depletion as seen from Hetauda and NAST, Nepal for 2016 https://www.nepjol.info/index.php/BIBECHANA/article/view/33405 <p>We analyzed Global positing System Total Electron Content (GPS-TEC) data of stations Hetauda (27.414 <sup>0</sup>N and 85.051 <sup>0</sup>E) and NAST (27.656 <sup>0</sup>N and 85.327 <sup>0</sup>E), Nepal which are a part of UNAVCO.We obtained the variation of rate of TEC index (ROTI) and S<sub>4</sub> index throughout the year 2016 for the two stations involved for the 32 all the Pseudo-Random Noise (PRN) numbers barring PRN number 4 which was inactive throughout the year. We chooses two stations data which are almost 40 km in distance and correlated the value of ROTI index with ROTI index and S<sub>4</sub> index with S<sub>4</sub> index and found that the ROTI index of Hetauda is well correlated with ROTI index of NAST with the highest being 94% for PRN 10 and the lowest being -13% for PRN 1. An extremely low correlation between S<sub>4 </sub>index of Hetauda and S<sub>4</sub> index of NAST was observed with the highest correlation being 8% in PRN 3, 32 and the lowest correlation of -15% in PRN 12.</p> <p>BIBECHANA 18 (2) (2021) 87-94</p> Basu Dev Ghimire Narayan Prasad Chapagain Balaram Khadka Gambhir Bidari Karan Bhatta Aditya Singh Thapa Copyright (c) 2021 Basu Dev Ghimire; Narayan Prasad Chapagain, Balaram Khadka, Gambhir Bidari; Karan Bhatta; Aditya Singh Thapa 2021-05-14 2021-05-14 18 2 87 94 10.3126/bibechana.v18i2.33405 Surface air temperature trends in Kathmandu Valley for 2011-2017 https://www.nepjol.info/index.php/BIBECHANA/article/view/29495 <p>In this study, we reviewed the maximum and minimum temperature trends of the Kathmandu valley over the period of 2011-2017. In addition, the average monthly temperature trends were studied annually for the same period, with the data made available from the Department of Hydrology and Meteorology (DHM) of Nepal. The annual temperature trended in the same direction, with winter temperatures being lower and summer temperatures being higher. The annual average minimum and maximum air temperature trends were found to be slightly rising at 0.097˚C/year and 0.04˚C/year, respectively. The mean air temperature in Kathmandu valley is increasing at a rate of 0.06 degrees Celsius per year, with 2016 being the warmest year and 2012 being the least warm, with annual mean temperatures of 19.82˚C and 19.32˚C, respectively. The temperature difference is much smaller in the summer (less than ~12˚C) than in the winter.&nbsp;</p> <p>BIBECHANA 18 (2) (2021) 95-104</p> A. Thapa A Silwal S P Gautam C K. Nepal S. Bhattarai D Timsina Copyright (c) 2021 A. Thapa, A Silwal, S P Gautam, C K. Nepal, S. Bhattarai, D Timsina 2021-05-17 2021-05-17 18 2 95 104 10.3126/bibechana.v18i2.29495 Wavelet and cross correlation analysis on some climatology parameters of Nepal https://www.nepjol.info/index.php/BIBECHANA/article/view/33805 <p>This study has been performed to understand the relationship between sunspot numbers (SSN) with climatology related parameters like temperature and rainfall from 1901 to 2016. The spectral characteristics of sunspot numbers, temperature and rainfall have been observed using continuous wavelet transform. Cross-correlation analyses were also performed to find any relation among temperature, rainfall, and sunspot numbers. The 9–11 year periodicity of sunspot numbers confirmed by wavelet transform in annual scale. The periodicity of high-frequency signals is identified between 4 to 11 years whereas the low frequencies signal is found throughout the periods of observation for temperature.&nbsp;Similarly, it is clear that there is more concentration of power between 8–16 years for rainfall. Cross-correlation analysis shows that the sunspot numbers is highly correlated with rainfall and temperature (correlation coefficient ~ 0.8054). The time lag relationship resulted in the almost simultaneous linear relationship between the temperature, rainfall, and the SSN tendency. The development of convective motions over the subtropics might be affected by the time rate of change of SSN combined with the surface temperature changes of diverse time scales. The convective motions were mostly controlled by the available amount of water vapor and the stability of the atmosphere that had a strong connection with the heat capacity of the concerned region. To produce more authentic findings for policy implications, further comprehensive and appropriate research can be undertaken and implemented in this very important field.</p> <p>BIBECHANA 18 (2) (2021) 105-115</p> Babu Ram Tiwari Jiyao Xu Binod Adhikari Narayan Prasad Chapagain Copyright (c) 2021 Babu Ram Tiwari, Jiyao Xu, Binod Adhikari, Narayan Prasad Chapagain 2021-05-29 2021-05-29 18 2 105 116 10.3126/bibechana.v18i2.33805 Effects of lightning as a disaster in Himalayan region https://www.nepjol.info/index.php/BIBECHANA/article/view/29168 <p>In Nepal, the main disasters are floods, lightning, fire, epidemics, and landslides. Among the several disasters in the Himalayan region, lightning is an important one. Because of the short distance (about 160 km) between the low land and peak Mount Everest from South to North, there is a variation of about 95<sup>0</sup>C temperature in these regions. The topographical features of the southern slopes and variation of temperature within this short distance influences the features of lightning and in this scenario, we get the positive cloud to ground lightning frequently which is more dangerous for human beings, animals, and property. In the Himalayan region, thunderstorms occur near the mountains due to which more positive charge can easily transfer from cloud to ground. Hence positive lightning occurs in the Himalayan region. The majority of the lightning-affected people are unaware of lightning safety and they should know the measures to protect life and property from lightning hazards. Hence by conducting awareness programs for the people of potential hazard areas, the number of injured people can be reduced as well as electrical, medical, military equipment can be somewhat protected from lightning.</p> <p>BIBECHANA 18 (2) (2021) 116-128</p> P B Adhikari A Adhikari A K Tiwari Copyright (c) 2021 P B Adhikari, A Adhikari 2021-05-29 2021-05-29 18 2 117 129 10.3126/bibechana.v18i2.29168 A study of dust structure nearby white dwarf WD1334-678 https://www.nepjol.info/index.php/BIBECHANA/article/view/37439 <p>A&nbsp;low flux density region nearby white dwarf WD1334-678 &nbsp;in the 140 µm AKARI survey maps&nbsp;has been systematically&nbsp;searched and found a far-infrared cavity centered at R.A. (J2000) = 13<sup>h</sup>38<sup>m</sup>14.4<sup>s</sup>, Dec.(J2000) = −68<sup>◦</sup>40’42”, in which minimum flux is 19.5 MJy/sr at 90 µm wavelength. The&nbsp;physical properties (Size, dust color temperature, dust mass) and thermodynamic property (Planck function distribution) of the cavity using 140 µm and 90 µm AKARI survey data. The size of the cavity is found to be 0.17<sup>◦</sup>× 0.12<sup>◦</sup><sup>&nbsp;</sup>has been presented. The dust color temperature is found in the range 17.70 ± 0.01 K to 18.81 ± 0.01 K. The Plank function distribution along major and minor diameters shows a very good agreement with sinusoidal fitting. The period of oscillation of dust particles along major and minor diameters are 3.2 Wm<sup>-2</sup>Sr<sup>-1</sup>Hz<sup>-1</sup>arcmin<sup>-1</sup>and 1.6 Wm<sup>-2</sup>Sr<sup>-1</sup>Hz<sup>-1</sup>arcmin<sup>-1</sup>, respectively.</p> <p>BIBECHANA 18 (2) (2021) 130-137</p> <p>&nbsp;</p> Ishwor Nath Joshi A. K. Jha B. Aryal Copyright (c) 2021 Ishwor Nath Joshi, A. K. Jha, B. Aryal 2021-06-03 2021-06-03 18 2 130 137 10.3126/bibechana.v18i2.37439 Muonium behavior in N-acetylglycine-N-methylamide https://www.nepjol.info/index.php/BIBECHANA/article/view/35761 <p>In muon spin rotation and relaxation (mSR) method, theoretical work using first-principles calculations helps to understand the stopping sites and charge states of muon in the sample materials. To support the mSR measurement on protein and DNA, a systematic first-principles study starting from the constituents of the protein has been performed. In this work, the behavior of muonium (Mu = m<sup>+</sup>e<sup>-</sup>, bound state of a muon and an electron which is like a light isotope of H atom with similar chemical properties) in a N-acetylglycine-N-methylamide (AGMA), a part of peptide bond, is presented. It is found that the stopping site of Mu is around O of unsaturated bonds between C and O in the AGMA. Further calculations towards whole protein and DNA will be performed to support mSR studies.</p> <p>BIBECHANA 18 (2) (2021) 138-142</p> Amba Datt Pant Copyright (c) 2021 Amba Datt Pant 2021-06-05 2021-06-05 18 2 138 142 10.3126/bibechana.v18i2.35761 Synthesis of antioxidative anthraquinones as potential anticancer agents https://www.nepjol.info/index.php/BIBECHANA/article/view/31234 <p>Antioxidant and antibacterial activities of natural anthraquinones namely chrysophanol (<strong>1</strong>) and emodin (<strong>2</strong>), and synthesized anthraquinones <em>viz.</em> 2-methylanthraquinone (<strong>3</strong>), anthraquinone (<strong>4</strong>), 2-bromoanthraquinone (<strong>5</strong>), rubiadin (<strong>6</strong>), chrysophanol diacetate (<strong>7</strong>), rubiadin diacetate (<strong>8</strong>) and 1,8-dimethoxy-3-methylanthraquinone (<strong>9</strong>) were investigated. Anthraquinones <strong>9</strong>, <strong>3</strong>, <strong>6</strong>, <strong>5</strong> and <strong>2</strong> exhibited a high DPPH• radical scavenging capacity (IC<sub>50</sub> = &lt;500 μg/mL) showing their therapeutic potentiality for the treatment of cancers. These anthraquinones <strong>1</strong>-<strong>9</strong> have also displayed a weak to moderate antibacterial activity against <em>Bacillus subtilis</em>. Chrysophanol diacetate (<strong>7</strong>) including emodin (<strong>2</strong>) have been appeared as the valuable antibacterials.</p> <p>BIBECHANA 18 (2) (2021) 143-153</p> Richa K. Gupta Ganesh M. S. Thakuri Gan B Bajracharya Ram Narayan Jha Copyright (c) 2021 Richa K. Gupta, Ganesh M. S. Thakuri, Gan B Bajracharya, Ram Narayan Jha 2021-06-09 2021-06-09 18 2 143 153 10.3126/bibechana.v18i2.31234 Distribution of dust properties around carbon rich AGB star: IRAS 04427+4951 using IRIS and AKARI survey https://www.nepjol.info/index.php/BIBECHANA/article/view/35394 <p class="western" style="margin-bottom: 0in; line-height: 150%;" align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">Interstellar dust properties using far-infrared bands analyze nature around asymptotic giant branch stars and stellar objects. Here, we present physical properties around the cavity region across an AGB star named IRAS 04427+4951 Sky View Observatory of IRIS, AKARI map, SIMBAD, Aladin v2.5, and Gaia Archive. The average color temperature and mass are 23.48 ± 0.009 K, 3.55×10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">27 </span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">kg (1.79× 10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-3 </span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">M</span></span></span><span style="color: #000000;"><sub><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">ʘ</span></span></sub></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> ) in IRIS data and 14.89 ± 0.004 K and 5.34×10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">28 </span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">kg (2.69 × 10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-2</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> M</span></span></span><span style="color: #000000;"><sub><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">ʘ</span></span></sub></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> ) from AKARI data. The size of isolated cavity-like structure around the AGB stars of 45.67 pc × 17.02 pc and 42.25 pc × 17.76 pc, respectively. The visual extinction is to be in the range of 3.2×10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-4</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> to 4.3×10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-4</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> mag in and 4.5 × 10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-3 </span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">to 7.4×10</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">-3</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> mag. The inclination angle is 86.15</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">0</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;"> and 93.92</span></span></span><span style="color: #000000;"><sup><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">0</span></span></sup></span><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">. The method and results we present developed can for the study of astrochemistry of interstellar medium.</span></span></span></p> <p class="western" style="margin-bottom: 0in; line-height: 150%;" align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: medium;">BIBECHANA 18 (2) (2021) 154-163</span></span></span></p> Devendra Raj Upadhyay Trishna Subedi Copyright (c) 2021 Devendra Raj Upadhyay 2021-06-11 2021-06-11 18 2 154 163 10.3126/bibechana.v18i2.35394