Physics in the 21st Century – A personal Perspective
Abstract:
In this presentation I will present major achievements up till now and my personal view on major problems and possible future directions in physics. In my personal opinion I will describe king of physics – Astrophysics and Cosmology, the queen – high energy particle physics, and the subjects – all other parts of physics.
Developing Curiosity of Performing Experiments
Abstract:
Science has tremendous role in the development of the modern age. There are at least two pillars of the science namely: theory and experiment. Both help each other to test their validity and for the creation of another new one. In addition, high speed capacity computers have emerged computational field of research that many people are involved in present days.
No matter how many models and theories are developed, they will be incomplete unless they are tested experimentally. It means that a theory merely predicts the nature with some limited frameworks. That is, there are many phenomena going on in the nature which can be explored by performing appropriate experiments. Though much tedious and expensive job is the experimental research in comparison to the theoretical and computational research, it is essential to develop efficient devices or material products. Therefore, attracting young scientists towards experimental research is one of the major problems which can be solved through motivating them by highlighting the beauty of experiments towards learning the nature.
Please look below for detailed schedule.
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Abstract Number: ANPA2023-N00045 Presenting Author: Sitaram Byahut (Invited) Presenter's Affiliation: Central Department of Physics, Nepal Title: Physics in the 21st Century – A personal Perspective Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract In this presentation I will present major achievements up till now and my personal view on major problems and possible future directions in physics. In my personal opinion I will describe king of physics – Astrophysics and Cosmology, the queen – high energy particle physics, and the subjects – all other parts of physics.
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Abstract Number: ANPA2023-N00044 Presenting Author: Hari Prasad Lamichhane (Invited) Presenter's Affiliation: Central Department of Physics, Nepal Title: Developing Curiosity of Performing Experiments Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Science has tremendous role in the development of the modern age. There are at least two pillars of the science namely: theory and experiment. Both help each other to test their validity and for the creation of another new one. In addition, high speed capacity computers have emerged computational field of research that many people are involved in present days.
No matter how many models and theories are developed, they will be incomplete unless they are tested experimentally. It means that a theory merely predicts the nature with some limited frameworks. That is, there are many phenomena going on in the nature which can be explored by performing appropriate experiments. Though much tedious and expensive job is the experimental research in comparison to the theoretical and computational research, it is essential to develop efficient devices or material products. Therefore, attracting young scientists towards experimental research is one of the major problems which can be solved through motivating them by highlighting the beauty of experiments towards learning the nature.
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Abstract Number: ANPA2023-N00094 Presenting Author: Binil Aryal (Invited) Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Nepal Title: Research Publication of Tribhuvan University: 1998 to 2022 Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract An analysis of research publications of Tribhuvan University in the last 25 years (1998-2022) will be presented and discussed. A comparison will be made with the annual publication rate of TU and Delhi University, Jawahar Lal Nehru University, India Innsbruck University, Austria, and Clemson University, USA for the same period. In addition, strengths, weaknesses, and challenges concerning interdisciplinary and multidisciplinary research outcomes of TU will be interpreted. Finally, a connection between the citations of articles published by the TU family and the Times Higher Education World University ranking of TU will be discussed. _x000D_
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Abstract Number: ANPA2023-N00027 Presenting Author: Anjan Dahal Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kathmandu, Nepal Title: Stopping Sites and Charge States of Muon in Azurin, Copper Protein Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Protein-mediated electron-transfer (ET) reactions are essential for converting energy in processes such as photosynthesis and respiration. For better understanding of the biological process, study of the ET mechanism is very important. Pioneered by K. Nagamine et al., ET in Cytochrome c protein [1], and DNA [2] reported using positive muon. To understand the muon experiment data, AD Pant et. al studied muon sites and charge state in amino acids and peptide bonds using first-principles calculations [3,4]. To understand ET in protein, we perform a systematic study to find stopping sites and charge states of muon in Azurin, Copper Protein.
Due to the complexity of biological system in geometry and dynamics, we have selected Azurin, which is a relatively small protein with copper as a single active site. We perform geometry optimization of structure and theoretical calculations using hybrid density functional (B3LYP/6-31G(d) and 6-31G(d,p)) in Gaussian 09 set of programs. Also, natural population analysis and electrostatic potential analysis helps to find the charge states and electronegative sites in the protein. Outcome of the research will provide valuable insights into the biochemistry and ET process in azurin and other big proteins. In the program, the stopping sites and charge states of muon in azurin will be presented.
References
[1] K. Nagamine et at., Physica B: Condensed Matter, 289 (2000) 631–635.
[2] E. Torikai et al., Hyperfine Interactions 138 (2001) 509–514.
[3] A. D. Pant et al., JPS Conf. Proc., 21 (2018) 011038.
[4] A. D. Pant et al., JPS Conf. Proc., 25 (2019) 011013.
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Abstract Number: ANPA2023-N00028 Presenting Author: Anup Shrestha Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kathmandu, Nepal Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Hypoxia, the region with low oxygen concentration in the tissue[1] is an important factor for tumor treatment. Since hypoxia causes resistance to the treatment [2], its detection is the foremost step towards the treatment process. Even though there are several existing methods to detect hypoxia, they come with limitations due to the requirement of special conditions and mainly due to invasive nature [3-5]. Instead, the newly proposed muon method does not require those special conditions and it is non-invasive in nature too, which is a great advantage over the currently existing methods[3,4]. Muon like a light proton, is more sensitive due to higher magnetic moment. Muonium, a bound state of muon and electron, is like a light isotope of hydrogen atom. In the proposed muon method, muonium undergoes spin exchange interaction with molecular oxygen to provide information about oxygen content in tumor tissue [3]. It is important to find the amount of muon beam dose to be used for the practical applications. Hence, we study the energy, intensity and profile (size) of the beam at various concentrations and sizes of the tumor. The estimated muon beam profile and energy using Monte Carlo simulation will be present in the program.
References
[1] W. C. Wilson and B. Shapiro, Anesthesiology Clinics of North America, 19 (2001) 769–812.
[2] P. Vaupel and L. Harrison, The oncologist, 9 (2004) 4–9.
[3] A. D. Pant et. al., Nuclear Instruments and Methods in Physics Research A, 1011 (2021) 165561.
[4] A. Pant et. al., Journal of Physics: Conference Series, 551 (2014) 012043.
[5] S. Chopra et. al., International journal of radiation biology, 85 (2009) 805–813.
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Abstract Number: ANPA2023-N00029 Presenting Author: Bidhya Thapa Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kathmandu, Nepal Title: Insights on the Interactions of Kaiso with p120 catenin from Molecular Simulations Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Protein-Protein interactions are crucial for the regulation of various cellular and biological processes. Molecular level insights on the interaction of Zinc finger (ZF) protein Kaiso with its binding partner p120 catenin are essential because of their role in development and cancers. Despite their important biological role, there is no structural characterization of the Kaiso-p120 catenin complex. In this work, we first modeled the optimum complex between Kaiso and p120 catenin through molecular docking and employed molecular dynamics (MD) simulations to investigate the structural features of this complex. Our MD simulation results show that the non contiguous 5’- and 3’- flanking regions of ZF domains in Kaiso interact with the 1-7 arm repeats of p120 catenin. The root mean square deviation (RMSD) measurements from the 500 ns of the MD simulation time reveal the stability of the Kaiso-p120 catenin complex. In addition, we identified the major interacting residues involved in the binding of these two proteins. Furthermore, we explored various non-covalent interactions such as; hydrogen bonds, salt-bridges, as well as hydrophobic interactions that are responsible for the complex formation and stabilization.
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Abstract Number: ANPA2023-N00046 Presenting Author: Chhabi Lal Gnawali Presenter's Affiliation: Department of Applied Sciences and Chemical Engineering, Pulchowk Campus, Institute_x000D_ of Engineering (IOE), Tribhuvan University, Lalitpur, Nepal Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract High surface area nanoporous activated carbon materials synthesized from natural carbon sources such as biowaste with large porosity and well-defined pore structures are preferred as electrode materials for high-performance supercapacitors. Here we report the fabrication of novel nanoporous activated carbon material from Phyllanthus emblica (Amala) seed stones by the chemical activation using potassium hydroxide (KOH) as an activator at different carbonization temperatures (700-1000 °C) under the nitrogen gas atmosphere. The precursor and the prepared carbon materials were characterized by the thermogravimetric analysis (TGA), Fourier transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Nitrogen adsorption-desorption isotherms estimated the specific surface area, pore size distribution, and average pore size. The total specific surface area ranges from 1360 to 1946 m2 g-1, and the total pore volume ranges from 0.664 to 1.328 cm3 g-1. The electrochemical energy storage performance was studied by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) in an aqueous 1 M sulfuric acid (H2SO4) solution in a three-electrode cell set up. The specific capacitance of the sample with best surface area was found to be 272 F g-1 at a current density of 1 A g-1 followed by 60% capacitance retention at a high current density of 50 A g-1. Additionally, the electrode showed outstanding cycle performance of 98 % after 10,000 charging/discharging cycles. These results indicate that the prepared nanoporous activated carbon material from Phyllanthus emblica seed stones led to the excellent supercapacitor electrode material for high-energy-storage supercapacitor applications.
Keywords: Phyllanthus emblica seed, KOH activation, nanoporous activated carbon, electrochemical measurement, supercapacitor
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Abstract Number: ANPA2023-N0006 Presenting Author: Keshab Chaudhary Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: A Study of Dust Properties nearby Pulsar PSRJ0856-6137 Using Iris and Akari Surveys Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract We have conducted a detailed analysis of the dust structure around PSR J0856-6137 in the far infrared band by using Sky View Virtual observatory in two surveys: IRIS (60 μ m and 100μ m) and AKARI (90μm  and 140μm) survey. We have studied different physical properties such as dust color temperature, dust mass, and Planck’s function. The maximum and minimum temperature was found to be 24.815 ± 0.008K, 23.899 ± 0.008K and 27.759 ± 0.016K, 26.178 ± 0.016K in the IRIS and the AKARI surveys respectively. In both cases, the offset temperature was obtained less than 2 k. The average dust mass was found to be 1.341×1027 kg and 1.460 ×1025 kg in the IRIS and the AKARI surveys respectively. We found a small offset temperature, which suggests that the system is in a state of thermal equilibrium. We conducted a comparison of these physical parameters and found similar results to those of earlier research. This research can aid in comprehending the evolution of the pulsar.
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Abstract Number: ANPA2023-N0007 Presenting Author: Lok Nath Sharma Presenter's Affiliation: Patan Multiple Campus, IOST, Tribhuvan University, Nepal Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Magnetic reconnection between Interplanetary Magnetic field (IMF) and magnetosphere allows solar wind to penetrate into Earth, generating geomagnetic storms. In this work, we investigate the effects of the storm of 23rd April 2023 into middle and low latitudes using geomagnetic field data from 5 Intermagnet ground stations. We look for possible connection with physical parameters from OMNIWeb data at 1-min resolution through cross-correlation analyses. The horizontal components of the Earth’s magnetic field show correlation with IMF parameters (By and Bz) of 0.72 and 0.96, respectively, with a time-lag up to 20 minutes, depending on station.
Keywords: Interplanetary magnetic field (IMF), solar wind, cross correlation, magnetosphere, horizontal components of the Earth’s magnetic field
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Abstract Number: ANPA2023-N00026 Presenting Author: Narayan Gautam Presenter's Affiliation: Central Department of Physics, Kirtipur, Nepal Title: Molecular dynamics simulations-based investigation of HDAC7-MEF2A molecular interactions Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Molecular dynamics simulations-based investigation of HDAC7-MEF2A molecular interactions
Narayan Gautam1, Prem P. Chapagain2, Narayan P. Adhikari1, and Purushottam B. Tiwari3
Affiliations: 1Tribhuvan University, Kathmandu, Nepal; 2Florida International University, Mi-ami, FL, USA; 3Georgetown University, Washington, D.C., USA
Corresponding Email: chapagap@fiu.edu; narayan.adhikari@cdp.tu.edu.np; pbt7@georgetown.edu
Abstract
Interactions between histone deacetylase 7 (HDAC7) and myocyte enhancer factor 2 (MEF2) regulate MEF2 activity. In the past, experimental studies were carried out for the interactions between these proteins and determined range of amino acids that are responsible for interactions. Despite prior experimental studies, to the best of our knowledge, there are no investigations characterizing the complex formation leading to identification of amino acid residues. In this study, we first modelled the HDAC7-MEF2A complex using AlphaFold and then conducted molecular dynamics (MD) simulations of the complex. Our analysis of MD simulations trajectories explored key amino acid residues that are involved in the complex formation through different interactions.
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Abstract Number: ANPA2023-N00017 Presenting Author: Num Prasad Acharya Presenter's Affiliation: Ph.D. scholar Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract We have investigated the evolution of dust charge and ion flow at the sheath boundary for the collisional magnetized dusty plasma in the presence of non-Maxwellian electron distribution in account of source and sink terms. The set of governing fluid equations have been solved for given initial conditions, whereas the dust charging equation have been solved using Newton-Raphson method. We have extended the Bohm sheath condition for dusty plasma using Sagdeev potential approach and it is found that gas pressure, obliqueness of magnetic field, ion loss term, and choice of electron distribution affect the evolution of dust charge and flow of positive ions at the sheath boundary.
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Abstract Number: ANPA2023-N00020 Presenting Author: Pradeep Karki Presenter's Affiliation: Tribhuvan University Title: EFFECT OF ELECTRON IMPACT IONIZATION SOURCE TERM ON MAGNETIZED PLASMA SHEATH Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract EFFECT OF ELECTRON IMPACT IONIZATION SOURCE TERM ON
MAGNETIZED PLASMA SHEATH
Pradeep Karki1*, Suresh Basnet1,2, and Raju Khanal2
1Department of Physics, GoldenGate International College, Tribhuvan University, Kathmandu 44600, Nepal
2Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu 44613, Nepal
Email: stonermind12@gmail.com
In this study, a fluid model has been used to explore the magnetized plasma sheath properties in the presence of ion-neutral collision and electron impact ionization source term. To solve the set of fluid equations, the initial conditions at the sheath edge and physical parameters are used. The obtained results reveal that the ionization source term affects the plasma sheath parameters: electric potential, net charge density, electron and ion density, and ion velocity. In terms of magnitude, the potential increases from about 17 to 68 as the magnitude of electron impact ionization frequency increases from 0 to 0.02. The net charge density is minimum at the sheath edge, and it increases towards the wall with its maximum peak value obtained in the sheath region. Once the maximum occurs, the net charge density decreases towards the wall. For the same increment of electron impact ionization frequency, the particle density decreases towards the wall, however, the decreasing rate is much slower for the ions than that of electrons. The electron density almost diminished at the wall while few ion densities reach the wall. Moreover, the velocity of ions increases toward the wall and the magnitude velocity with which it strikes the wall increases from about 5.7 to 11.6.
References:
[1] T. E. Sheridan and J. A. Goree, IEEE Trans. Plasma Sci. 17, 884 (1989).
[2] K. U. Riemann, J. Phys. D: Appl. Phys. 24(4), 493 (1991).
[3] N. Sternberg, V. Godyak, and D. Hoffman, Phys. Plasmas 13, 063511 (2006).
[4] S. Basnet, A. Maskey, A. Deuja, and R. Khanal, Phys. Plasmas 28, 083705 (2021).
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Abstract Number: ANPA2023-N0009 Presenting Author: Prakash Man Shrestha Presenter's Affiliation: Patan Multiple Campus, IoST, TU, Nepal Title: Temporal variation of Atmospheric Ozone over Kathmandu Valley Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract The main aim of this project is to study temporal the variation of atmospheric ozone over Kathmandu Valley (27.72o N, 85.32oE, 1350 m asl). The daily data of Total Ozone column (TOC) is received from
OMI satellite of NASA for 11 years of solar cycle-24 (2008 to 2018). The monthly, seasonal and annual variations of TOC are studied. The maximum value of monthly average of TOC is found 282 ± 8 DU in April, while the minimum value is found 252 ± 7 DU in December. The results also shows that TOC is seasonal dependent with larger value of TOC 174 ± 10 DU in pre monsoon and lower value of 258 ± 5DU in post monsoon. The annual average of TOC exhibits slightly variable with a maximum 280 ± 15 DU in 2015 and minimum 249 ± 10 DU in 2009. The average value of TOC during the whole study period is found 267 ± 17 DU, which indicates a good amount of stratospheric ozone content over Kathmandu Valley. Continuous wavelet transform (CWT) is also used to analysis variation of TOC. The power density of TOC 25000 DU2 is recorded from 2010 to mid of 2011 and 2015 to end of 2017. This research work is beneficial for the further identification and analysis of TOC at different places with same geography.
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Abstract Number: ANPA2023-N00010 Presenting Author: Puranjan Kafle Presenter's Affiliation: Western Regional Campus,Pokhara Title: Loop Quantum Gravity: A interdisciplinary topic Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Abstract
Loop quantum gravity (LQG) is a theoretical framework that attempts to reconcile the principles of general relativity, the theory of gravitation, with quantum mechanics, the theory that describes the behavior of matter and energy at the smallest scales. In LQG, space-time is quantized into discrete units, and the geometry of space-time is described in terms of spin networks, which are graphs representing the interconnections between space-time points. There are various aspects or fundamentals to this topic. This report aims to provide a wide view on various aspects of their fundamentality and provide with a wider perspective to its challenges and sucess majors to upbring as a major contendor for the holy grail of physics "The Theory of Everything ". This report is included with details on tge basic principles of Loop Quantam Gravity. It includes : Canonical quantization,Discrete space-time,Holonomies and connections,Spin networks,Background independence,Diffeomorphism invariance,Emergence of space-time. Also providing a wider view to its challenges and promising future directions, This report impacts on other various big topics in physics such as Cosmology, Particle Physics, Philosophical bibilographies as well as Quantam Mechanics.
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Abstract Number: ANPA2023-N0008 Presenting Author: Purna Jyoti Shakya Presenter's Affiliation: Patan Multiple Campus, IoST, Tribhuvan University, Nepal Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Ultra low frequency (ULF) waves are an important consideration to identify the dominant process that transfer energy from solar wind to Earth’s inner magnetosphere as they propagate electromagnetic energy over vast distance with little dissipation. The waves observed on the Earth depends on conditions in the solar wind and in the magnetosphere. In this work, we investigate the Pc pulsation observed in the 12-15 UT time interval during geomagnetic storm of September 8th 2017 using data from the SuperMAG and the OMNIWeb services. We used Pc pulsation data observed at T48 station (geographic latitude: 54.8o, geographic longitude: 293.19o), Schefferville, Canada. Cross-correlation analysis shows that Pc2, Pc3, Pc4 and Pc5 ULF wave are positively correlated with interplanetary magnetic field, AE index and Polar cap index. Similarly, cross-correlation of Pc pulsations with solar wind density (Nsw), solar wind pressure (Psw) and solar wind velocity (Vsw), shows that they are positively correlated with no time lag, indicating sudden increase in solar wind density and velocity due to IP shocks result in a gradual increase in dynamic solar wind pressure and sudden compression from the Earth’s dayside magnetosphere. As a result, acoustic magnetic wave are ejected into the magnetosphere.
Key words: Ultra Low Frequency (ULF), Pc Pulsation, Geomagnetic Storm, Magnetosphere.
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Abstract Number: ANPA2023-N0002 Presenting Author: Keshab Pandey Presenter's Affiliation: Department of Physics, Daegu University, Gyeongsan 38453, South Korea Title: Modification of Tungsten Disulfide for Electrochemical Energy Storage and Conversion Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Tungsten disulfide (WS2) is modified, by using ambient solution plasma, for electrochemical energy applications which are hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and flexible supercapacitor applications. Herein, the effect of time-dependent plasma treatment on WS2 is investigated, resulting that the optimum time (60 min) shows the best performances of low overpotential of -0.19 V at -10 mA cm-2 and 0.21 V at 10 mA cm-2 with the corresponding Tafel slopes of 113 mV dec-1 and 124 mV dec-1 for HER and OER, respectively. In addition, a high specific capacitance of 157.5 F g-1 at 1 A g-1 with an energy density of 14 Wh kg-1 and power density of 400 W kg-1 for the flexible supercapacitor is obtained. Reliable flexibility with high specific capacitance retention (94.0%) and coulombic efficiency (89.5%) after 5,000 cycles are also demonstrated. The increased electrochemically active surface area, lower impedance, and the phase transition from 2H to 1T, compared to the precursor WS2, are ascribed to the better HER, OER, and supercapacitor performance.
Keywords: Tungsten disulfide; ambient solution plasma; hydrogen evolution reaction; oxygen evolution reaction; supercapacitor.
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Abstract Number: ANPA2023-N00081 Presenting Author: Rajendra Neupane Presenter's Affiliation: Central Department of Physics Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract We performed a temporal and spectral study of emission from blazar OJ 287 using an XMM-Newton observation in April 2020. Among the various fitted models used to characterize the spectrum, (log-parabola+black-body) model fits the spectrum best which indicates that the observed X-ray emission is a result of a combination of synchrotron and thermal emission processes, implying that the overall X-ray emission is driven by both non-thermal and thermal mechanisms. The value of fractional variability of 2.073±0.037 indicates that the source is highly variable. The results of our analysis show a significantly higher net count rate of 5.651±0.025. Despite the much shorter exposure time of just 9 ks in April 2020, compared to the 53 ks and 19 ks exposure time for the 2015 and 2018 observations respectively, the effect of the flare is still apparent in the higher net count rate (5.651±0.025) obtained from the more recent observations in April 2020.
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Abstract Number: ANPA2023-N00019 Presenting Author: Ramesh Khanal and Rajan Ghimire Presenter's Affiliation: Student Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract This work is concerned with the effect of non-Maxwellian electrons and obliqueness of magnetic field on magnetized plasma sheath characteristics, in which plasma interacts with tungsten (W) and molybdenum (Mo) surfaces via non-neutral plasma sheath using two fluids model. It is assumed that the singly charged positive ions are treated as warm fluid whereas the electrons obey q-nonextensive distribution. It is found that the q-nonextensive distributed electrons and the temperature of ions affect the entrance velocity of positive ions, which is a key parameter in the plasma sheath formation. Also, the nonextensive parameter q affects the distribution of ions and electrons in the sheath region and their distributions explicitly related with the electrostatic potential variation. The parallel and
perpendicular components of ions velocity are affected by the obliqueness of magnetic field. As the nonextensivity of electrons increases, the gradient in electric potential increases towards the wall and hence the impact energy also increases. The obliqueness of magnetic field and impact energy of ions is a key factor that determines the physical sputtering rate, particle reflection and absorption from the target surface. Furthermore, the probability of particle reflection coefficient from the W-surface is higher than that of Mo-surface.
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Abstract Number: ANPA2023-N00016 Presenting Author: Roshan Chalise Presenter's Affiliation: Central department of Physics, Tribhuvan University, Kathmandu, Nepal, Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Atmospheric pressure plasma (APP) finds extensive applications across various fields to enhance human life quality such as food safety (microbial inactivation, bacteria-free food), healthcare (cancer treatment, wound healing, blood coagulation, dental procedures), micro-fabrication (etching, chemical vapor deposition), agriculture (insecticide, sterilization, growth enhancement, fertilizers), and environmental science (air and water pollution treatment). In this study, we have developed and characterized gliding arc, dielectric barrier discharge, and plasma jet systems using natural air in the laboratory of the Central Department of Physics. These plasma systems were then applied in agriculture fields (such as leaf mustard, paddy, cauliflower, coriander seed, and mushroom) both directly and indirectly (by exposing plasma to water and subsequently using the treated water on crops). The APP generates various reactive species, including nitrate, nitrite, hydrogen peroxide, and OH functional groups, which alter the properties of the seeds, seed germination, seedling growth, and water. The treated substrates exhibit decreased contact angles, rendering seeds more hydrophilic, enabling increased water absorption and improved germination rates. Plasma-activated water contains a higher concentration of reactive species, promoting growth enhancement and serving as a fertilizer and pesticide.
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Abstract Number: ANPA2023-N00030 Presenting Author: Roshan Pudasaini Presenter's Affiliation: Kathmandu University Title: Muonium behavior in derivatives of Hemoglobin: a DFT study Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Muon is a spin-halved subatomic particle that can be found in cosmic rays (naturally) and accelerator facilities through pion decay. It has a mass that is around 207 times that of an electron and 1/9 that of a proton. Since the muon's gyromagnetic ratio is around three times greater than that of the proton, it is higher sensitive with respect to proton to magnetic field. Muon has two unique properties that make them unique tools: spin polarization and asymmetric decay to positron (caused by parity violation in weak contact). By stopping muons into the injected material, the local electronic and spin states of materials can be revealed through the muon spin rotation and relaxation (muSR) approach. Muonium on the other hand, is bound state of two lepton particles - positive muon and an electron with similar chemical properties of H atom. Muon method examines the local and dynamic state of spin, electron, proton, ions, and hydrogen in materials. It can also investigates phenomena based on these processes, such as electron transfer in the respiratory system, photosynthesis process, illness detection, clinical and medical fields, and reaction dynamics, catalytic processes, molecule concentration, magnetic behaviors etc.
In this study, the stopping site and charge states of muon and muonium in derivatives of hemoglobin have been studied through the first-principles approach. The stopping site of muon and muonium in derivatives of hemoglobin with extended main chain structure have been estimated.
The HOMO-LUMO gap and hyperfine coupling constant will be extracted from external files to understand the electronic states and interaction of muon with nearby nucleus.
By analyzing the stopping sites of muon and muonium within the hemoglobin structures, we aim to understand their preferential binding locations and the influence of molecular variations on their behavior. The obtained results shed light on the interactions between muon, muonium and the hemoglobin derivatives, revealing potential implications for their reactivity and functionality. Our DFT calculations not only contribute to the fundamental understanding of muon and muonium behavior in hemoglobin but also pave the way for further exploration of their interactions with other biomolecules. The findings from this study can potentially guide future experimental investigations and inspire the development of novel applications of muon in cancer research.
In the initial findings of the muonium behavior within the heme group of Deoxyhb, Oxyhb, and Cohb, we observed that the muonium tends to settle near the nitrogen atom of the pyrrole ring in the heme group. Conducting a theoretical analysis will be crucial in determining the precise location where the muon stops and the specific charge states it adopts in hemoglobin. This information will be invaluable in supporting the experimental investigation.
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Abstract Number: ANPA2023-N00082 Presenting Author: Saroj Pandeya Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu 44613, Nepal Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract We have employed the self-consistent kinetic theory to study the linear dispersion relation of_x000D_
ion acoustic waves in four-component plasma consisting of nonextensive hot electrons,_x000D_
Maxwellian cold electrons, positive ions, and dust particles. The dust charging process with_x000D_
the modified ion acoustic wave damping, as well as its unstable mode, has been graphically_x000D_
illustrated. It is found that the dust charging mechanism depends on the density of hot_x000D_
electrons, the degree of nonextensive electron distribution, and the temperature ratio of hot_x000D_
to cold electrons. It is shown that the damping and instability rates of ion acoustic waves due_x000D_
to dust charge fluctuations explicitly depend on the choice of electron distribution and the_x000D_
magnitude of dusty plasma parameters. In addition, we have studied the ion acoustic Landau_x000D_
damping in the absence of dust particles. It is found that the weak damping region broadens,_x000D_
while the strong damping region shrinks and is shifted toward the short wavelength region_x000D_
for the increase in the temperature ratio of hot to cold electrons.
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Abstract Number: ANPA2023-N0001 Presenting Author: Sujan Bhandari Presenter's Affiliation: Central Department of Physics Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract Phosporic Acid (H_3PO_4) can be used to activate different precursors and produce activated carbon(AC) ,a porous material with high adsorption capacity and surface area. This research compares how AC is made using different locally available precursors namely Amla seeds and Harro seeds. We look at how carbonization temperature affects the AC yield, surface area, pore structure and electrochemical properties. We use different methods to analyze the AC samples such as scanning electron microscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. We show that the best conditions for making AC depends on the type of precursor. We also talk about the use of AC for storing energy.
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Abstract Number: ANPA2023-N00021 Presenting Author: Suresh Basnet Presenter's Affiliation: Tribhuvan University Location: Central Department of Physics, T.U., Nepal Show/Hide Abstract In laboratory and space plasmas, the emission of electrons from the surface significantly affects the characteristics of plasma sheath formed at that surface, which is crucial to understanding the overall plasma-wall interaction mechanism. In this work, the collisional fluid model is used for laboratory dusty plasma, whereas collisionless model is used for lunar dusty plasma. We have extended the Bohm sheath criterion for the formation of stable plasma sheath in account of electron emission from the surface, loss of ion flux, and gas pressure for the collisional laboratory dusty plasmas. It is found that ion flow at the sheath boundary is considerably influenced by the concentration of electron emission, ion loss term, and gas pressure. The equilibrium evolution of dust charge explicitly determines the magnitude of ion flow at the sheath boundary. The plasma parameters adopted in the present case are reliable in laboratory and space dusty plasmas, especially dusty plasma environment on the lunar surface. The surface of Moon and dust grains are electrically charged due to interaction of solar-wind plasma and photoemission electrons from the surface due to solar ultra-violet radiation. In addition, the plasma sheath characteristics, dust charging process, and stable dust levitation on the sheath region have been studied.
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