This year’s in-person sessions will be held at:
- Central Department of Physics, Tribhuvan University, Kirtipur, Nepal
- Fayetteville State University, Fayetteville, NC
Please look below for detailed schedule.
Central Department of Physics Sessions
Please look below for detailed schedule.
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Abstract Number: ANPA2024-N0002 Presenting Author: Om Prakash Niroula Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal Title: Welcome message by Department Chair Location: In-Person Presentation, CDP Show/Hide Abstract |
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Abstract Number: ANPA2024-N0003 Presenting Author: Narayan Prasad Chapagain, PhD Presenter's Affiliation: Department of Physics, Amrit Campus, Tribhuvan University, Thamel, Kathmandu Title: Space Weather at Low-Latitudes and Prospects of its Forecasting Location: In-Person Presentation, CDP Show/Hide Abstract Space is the ultimate high ground from which a variety of satellite-based surveillance, communications, and navigation systems operate. As these technologies become increasingly intertwined into our day-to-day lives and national security, it becomes paramount to understand how they can be disrupted. When plasma in the ionosphere between a satellite and a receiver is turbulent, the transmitted signals scintillate. This scintillation poses a problem for a receiver, which can lose the ability to track that signal, adversely affecting technologies that rely on this system. Although low- to mid-latitude ionospheric irregularities have been studied for several decades, the capability to forecast their occurrence and day-to-day variability is still elusive and remains a challenge in space physics. In this presentation, our investigation of the morphology and dynamics of these ionospheric plasma irregularities will be discussed. Similarly, total electron content (TEC), i.e. the total number of electrons present per square meter along a path between a radio transmitter from a satellite and a receiver, using GPS network widely distributed across Nepal will be presented to study the trend of the ionospheric variability over Nepal. The ionospheric anomalies using the TEC data during solar eclipse as well as before and after the huge Gorkha Earthquake in Nepal (28.23°N, 84.73°E) with a magnitude of 7.8 on April 25, 2015 have been analyzed.
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Abstract Number: ANPA2024-N0004 Presenting Author: Roshan Chalise Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: Development and Characterization of Gliding Arc Plasma Jet (GAPJ) Location: In-Person Presentation, CDP Show/Hide Abstract In this work, we present the development of an atmospheric pressure gliding arc plasma jet (GAPJ) that operates in ambient air to generate non-thermal plasma. This technology, developed from our locally available material, holds potential applications for treating the designated substrate region. There is a direct relationship between airflow rate and jet length. The discharge was characterized using electrical and optical methods, and it was discovered that airflow and applied voltage impacted the discharge's electrical and optical parameters, including power, gas flow rate, and applied voltage. The produced plasma is contained to create a plasma plume and has potential uses in specific fields of decontamination and sterilizing in the food industry, pharmaceutical, and medical sectors.
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Abstract Number: ANPA2024-N0005 Presenting Author: Santosh Dhungana Presenter's Affiliation: Tribhuvan University Title: Electrical and Optical Characterization of Knife Shaped Gliding Arc Discharge (GAD) System and Its Application on PAW Production and Seed Treatment Location: In-Person Presentation, CDP Show/Hide Abstract GAD is an auto-oscillating discharge that starts between electrodes of divergent geometry through the force of the laminar or turbulent flow of gas or air. In this discharge system, a breakdown of atmospheric gas occurs at the shortest gap between the two divergent electrodes. It is a simple and inexpensive way to generate non-thermal plasma and has various applications in the fields of material processing, gas conversion, medical sterilization, and agriculture. In this study, the GAD system was constructed from different metals, and their electrical and optical characteristics were studied on the basis of gas flow rates and applied voltages. Plasma activated water (PAW) generated from GAD discharge system is characterized. A significant change in physiochemical properties of water is observed. Direct treatment of seed by GAD has changed the surface properties of seed. This is illustrated by contact angle measurement, conductivity tests, and FTIR analysis of seeds.
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Abstract Number: ANPA2024-N0006 Presenting Author: Devendra Raj Upadhyay Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal Title: Attenuation of Photons, Neutrons, and Heavy Ions in Niobium Alloys for Accelerator Applications Location: In-Person Presentation, CDP Show/Hide Abstract The present theoretical and simulation work investigates the attenuation properties of gamma-ray energies ranging from 1 keV to 100 GeV. Key parameters analyzed include linear and mass attenuation coefficients, half-value and tenth-value layers, mean free paths, and effective conductivity. These properties are examined in the context of increasing photon energy levels impacting accelerator cavities and conventional conducting materials. Additionally, fast neutron removal cross sections are studied using the photon shielding and dosimetry (Phy-X/PSD) software. Ion stopping potentials and projected ranges are analyzed using the Stopping and Range of Ions in Matter (SRIM) tool. Furthermore, we present findings on photon trajectories and dose attenuation using the particle and heavy ion transport code system (PHITS) in niobium and its alloys, which are considered as potential alternatives for cavity formation in accelerator physics. The use of niobium and its alloys could offer significant advantages in efficiency and effectiveness for accelerator applications.
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Abstract Number: ANPA2024-N0008 Presenting Author: Bed Prasad Pandey Presenter's Affiliation: CDP,TU Title: High Speed Application of Source Pocket Hetero-Dielectric Double Gate TFETs Location: In-Person Presentation, CDP Show/Hide Abstract High Speed Application of Source Pocket Hetero-Dielectric Double Gate TFETs
Bed Prasad Pandey1, Santosh Kumar Pandit1, Sanju Shrestha1, Om Prakash Niraula1
and Kavindra Kumar Kavi2
1Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal,
2Electronics and Communication Engineering Department, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, India
Email: bedprasadpandey80@gmail.com
Abstract:
Tunnel field effect transistor (TFET) is studied for its ability to have low power consumption due to low sub-threshold swing (SS), in addition it has low trans-conductance (g_m ) and high on-off ratio. Hence, silicon-based double-gate TFET is optimized with source pocket (SP) along with a combination of high-k materials forming hetero-dielectric at the gate. The various physical parameters mentioned above of such SP heterodielctric TFET (SP HD TFET) is studied using Silvaco, simulations are performed in Technology Computer- Aided Design (TCAD). The nature and the calculated values of the drain current, electric field, band energy, subthreshold swing (SS), Ion/Ioff ratio shows that it’s appropriate application as low power as well as a high-speed performance.
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Abstract Number: ANPA2024-N0009 Presenting Author: Santosh Kumar Pandit Presenter's Affiliation: Ph.D Scholar,CDP, TU Title: Simulation, modeling and optimization of Source Pocket- Based Hetero-Dielectric Double- Gate TFETs for enhance performance. Location: In-Person Presentation, CDP Show/Hide Abstract A physics-based 2-D analytical model for electrical characteristics such as electric field, surface potential, and drain current of source pocket hetero-dielectric double-gate tunnel FET (SP-HD-DG-TFET) is proposed to simultaneously increase the drain current and immune the sub threshold swing (SS). The presented structure of the device consists of a source pocket of highly n+-doped Silicon with a horizontally stacked gate-oxide structure of HfO2-SiO2. The influence of incorporating hetero dielectric and work function engineering shows a significant enhancement in ON-state current ION (4.35× 10–5 A/μm) and lower leakage current IOFF (1.47× 1012 A/μm), ION/IOFF (1.36× 1012), smaller sub threshold swing SS (9.7 mV/decade). We examined an optimized hetero gate dielectric to reduce am bipolar current conduction, leakage current, and boost ON-current for this purpose (ION). The technology computer-aided design (TCAD) simulations were carried out.
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Abstract Number: ANPA2024-N00010 Presenting Author: Saddam Husain Dhobi Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal Title: Effect of Thermal Quantum Species Screening on Fuel Cell Performance Location: In-Person Presentation, CDP Show/Hide Abstract The objective of this research work is to understand how the voltage and power of proton exchange membrane fuel cells (PEMFCs) are affected by how thermal quantum species at 315K play a role on performance of PEMFCs, especially for Pt/C electrons. For this author use an online MATLAB student package and compared two types of characteristics, I-V and I-P with adjusting the activation potentials of Pt/C. The results show as current increased, the voltage dropped steadily from 0.45V to 0.88V in the I-V characterization. However, in the I-P characteristics, power initially increased from 0.95 W to 1.27 W, but then decreased sharply at an activation potential of 40mV. Similarly, at 55 mV activation potential, the voltage dropped from 0.35V to 0.78V as current increased, while power initially rose from 1.30 W to 1.55 W before decreasing. This decline in power was due to screening effects around the electrodes caused by the formation of quantum species in the system. this like oxides formed around electrode of battery electrode and reduce the performance of batteries.
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Abstract Number: ANPA2024-N00011 Presenting Author: LEO DYAJI Presenter's Affiliation: UNIVERSITI MALAYA, MALAYSIA Title: Innovations in Green Chemistry for Minimizing Environmental Impact and Promoting Sustainable Product Design Location: In-Person Presentation, CDP Show/Hide Abstract The increasing awareness of environmental sustainability and the urgency to mitigate the adverse effects of industrial processes have led to significant advancements in green chemistry. This article explores recent innovations in green chemistry aimed at minimizing environmental impact and promoting sustainable product design. It provides a comprehensive overview of novel methodologies and materials that reduce the use of hazardous substances, lower energy consumption, and enhance the recyclability of products. Key areas of focus include the development of eco-friendly solvents, catalysts, and renewable feedstocks, as well as the integration of life cycle assessment (LCA) in the design of sustainable products. Case studies demonstrating successful applications of green chemistry principles in various industries will be presented, highlighting the economic and environmental benefits achieved. This research underscores the potential of green chemistry to drive sustainable industrial practices and contribute to global efforts in achieving environmental sustainability. The findings will advocate for broader adoption of green chemistry techniques to foster innovation and resilience in the face of environmental challenges.
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Abstract Number: ANPA2024-N00012 Presenting Author: Hari Shankar Mallik Presenter's Affiliation: Central Department of Physics, TU, Kirtipur, Kathmandu, Nepal Title: Level crossing resonance studies of derivatives of hemoglobin using muon Location: In-Person Presentation, CDP Show/Hide Abstract To be added
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Abstract Number: ANPA2024-N00013 Presenting Author: Narayan Gautam Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kathmandu, Nepal Title: Characterizing HDAC7-MEF2A complex formation Location: In-Person Presentation, CDP Show/Hide Abstract Histone deacetylases (HDACs) regulate gene expression and play an important role in regulation of neuronal cell death through interactions with other binding partners such as MEF2A. Myogenesis, neuronal survivals, and axon branching are associated with HDAC-MEF2 transcription complexes. To the best of our knowledge, structural investigations of this functional complex are limited, and no crystal of HDAC7-MEF2A complex is available. Prior experimental studies were determined the range of amino acids responsible for interactions. In this study, we first modeled the HDAC7-MEF2A complex and then performed molecular dynamics (MD) simulations of the complex to explore the crucial residues that are establish molecular interact between these two proteins. Our results predict that SER82 and LYS96 in HDAC establish Hydrogen bonds with ASP63 in MEF2A, respectively. In addition, LYS96 in HDAC7 and ASP63 in MEF2A also predicted to form a salt bridge. Our analysis of the HDAC7-MEF2A binding shows that hydrophobic interactions play the main role in complex formation and stabilization of the complex.
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Abstract Number: ANPA2024-N00033 Presenting Author: Keshab Chaudhary, Dipendra Prasad Kalauni Presenter's Affiliation: Central Department of Physics , Tribhuvan University Title: Machine Learning Driven Formation Energy and Lattice Parameter Prediction of Full Heusler Alloys: X2YZ Location: Poster Presentation Show/Hide Abstract
Machine learning, a part of both AI and data science, aims to enable machines to recognize patterns and generate decisions or predictions without requiring explicit programming. This work is based on the application of supervised learning in material science, utilizing machine learning as a useful tool for quickly identifying new materials and predicting their features. To predict the essential formation energy and lattice parameter, two supervised learning regression approaches within machine learning—random forest regression and gaussian process regression—have been used. In this study, the formation energy and lattice parameter of 140 full Heusler compounds were predicted by selecting 24 features of cubic structures with an 80% and 20% train-test split. Features such as volume, atomic radii, atomic mass, electro-negativity, lattice angle, band gap, formation energy, covalent radii, density, total magnetization, number of atoms, etc. were employed to predict the lattice parameter of cubic Heusler compounds (X2YZ). Model performance was evaluated using evaluation criteria such as mean squared error (MSE), mean absolute error (MAE), and R-squared (R2). After using both models, the obtained values for formation energy were as follows: Random Forest Regression—R2: 0.658, MSE: 0.011, MAE: 0.091, Gaussian Process Regression—R-squared: 0.734, MSE: 0.246, MAE: 0.396, indicating the GPR's higher accuracy. Similarly, for lattice parameter prediction, GPR demonstrated lower MSE (0.0023) and MAE (0.0396) values compared to RFR (MSE: 0.0025, MAE: 0.0423), with a slightly higher R-Square value (GPR: 0.9768, RFR: 0.9744), suggesting better overall goodness of fit. This study highlights the success of both RFR and GPR models in predicting lattice parameters and formation energy. It emphasises the potential of machine learning to efficiently and cost-effectively explore significant phase spaces in the search for new materials.
Keywords: Formation Energy, Lattice parameter, Machine learning, Heusler compound, Random Forest Regression (RFR), Gaussian Process Regression (GPR), R-squared (coefficient of correlation), Mean square error (MSE), Mean absolute error (MAE).
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Abstract Number: ANPA2024-N00032 Presenting Author: Gokarna Banjade Presenter's Affiliation: Patan multiple campus Title: PREDICTION OF NEPAL'S 2021 EARTHQUAKE TREND USING SCALED INPUT IN A 4-LAYER LSTM MODEL. Location: Poster Presentation Show/Hide Abstract Earthquake prediction is a critical field of study in Nepal due to its susceptibility to seismic activity caused by the energy released during plate movements. In this work, we use the LSTM model and advanced computer programs to analyze earthquake data and find trends. We utilize a deep neural network approach to enhance prediction accuracy. The dataset used from May 4, 1964, to May 23, 2023, was obtained from the USGS (United States Geological Survey) catalog of magnitude Mw ≥ 4. In this work, we aimed to predict earthquakes and trends around the year 2021 using data from a series of past earthquakes. A dataset of 1094 data points was used,with 88 for training and 1020 for testing. The primary focus was on earthquake event 1040, which occurred on May 18, 2021. The trained model is then used to predict the future trend of
earthquakes. We consider four features like magnitude, time interval (in days), longitude, and latitude, and we find the best-fit model from the Kerus tuner-coded Python program. The program is executed multiple times, with each run corresponding to a specific number of epochs ranging from 100 to 1500. We observed that training the model with a larger number of epochs improved the
prediction accuracy for the longitude, latitude, time interval, and magnitude features. Specifically, we observed that during epoch 1000, the prediction for longitude, latitude, time interval, and
magnitude of observed data tends to match with test data and is better as compared with other epochs. Reviewing the graph and its data, it becomes clear that errors are significantly lower during
epoch 1000, as supported by the analysis of mean square error and mean absolute error.
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Abstract Number: ANPA2024-N00031 Presenting Author: Ambika Shahi Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur 44613, Kathmandu, Nepal Title: Prediction of Lattice Parameter and Formation Energy of Cubic Semi-Heusler Alloys Location: Poster Presentation Show/Hide Abstract Materials advancement is the propelling forces for present-day science and technology. In recent years, machine learning (ML) models are becoming popular in the field of materials research due to their remarkable precision at low computational cost. Notably, semi-Heusler alloys are getting attention due to their applications in thermoelectric, topological, shape memory as well as spintronics. In this work, we apply ML models to predict the lattice parameter and formation energies of selected semi-Heusler alloys XYZ (where X and Y are transition elements, and Z is a main group element) using dataset sources from materials project database. We predict the lattice parameters of 145 cubic semi-Heusler alloys using 24 features through regression models, specifically, Random Forest Regression (RFR) and Gaussian Process Regression (GPR). Subsequently, the labelled datasets were split into training and testing sets in the ratio of 80:20 for both the lattice parameter and formation energy prediction. A feature versus contribution barplot was created to show the contribution level of each parameter for predicting results. Assessing the model’s performance, we computed R-square, mean square error, and mean absolute error for RFR (GPR) models. Our findings suggest that GPR out performs RFR in predicting the lattice parameter, while RFR predicts the formation energy of cubic semi-Heusler alloys better. Furthermore, a heatmap shows the correlation between the actual data and the predicted data. This study demonstrates the developing predictive models using machine learning in materials science which enables deeper understanding of lattice parameter and formation energies.
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Abstract Number: ANPA2024-N00030 Presenting Author: Aatiz Ghimire Presenter's Affiliation: Tribhuvan University Title: Deep Learning Technique for Forest Fire Detection using Satellite Imagery Location: Poster Presentation Show/Hide Abstract Forest fire is one of the major causes of air pollution in Nepal, which also an fueling agent to climate change. To detect and identify forest fire is not an easy task in dense and isolated forest. To overcome this problem, we suggest a deep learning-based model to detect forest fire using satellite imagery.
The satellite image in this research is extracted from different opensource satellite data products such as Sentinenal-2 and Landsat Satellites. These data products contain multiple hyper-spectral band images, where we require only Red, Blue and Green Band Images. These images are then converted into True color Images. The Images containing the Forest Fire are then annotated manually with the help of label studio. This data is passed to Convolutional Neural Network to learn the forest fire features within the Satellite Imagery. This will detect fire, smoke and burnt areas in this Satellite Imagery. The dataset made for this purpose is split into 80-20 and made validation split to check the accuracy and performance of the model.
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Abstract Number: ANPA2024-N00029 Presenting Author: Sabita Pandey Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, 44613 Kathmandu, Nepal Title: Electronic and Magnetic Properties of Honeycomb Layered Oxide: Na3Mn2SbO6 Location: Poster Presentation Show/Hide Abstract Electronic and Magnetic Properties of Honeycomb Layered Oxide: Na3Mn2SbO6
Sabita Pandey1,2*; Pratima Khadka1,2; Sarita Lawaju1,2, and Madhav Prasad Ghimire1
1Central Department of Physics, Tribhuvan University, Kirtipur, 44613 Kathmandu, Nepal
2Condensed Matter Physics Research Center (CMPRC) Butwal, Rupandehi, Nepal.
*sabita.775511@cdp.tu.edu.np
Abstract
The electronic and magnetic properties of Na3Mn2SbO6 (NMSO), a honeycomb layered oxide, were explored through density functional theory (DFT) using the full-potential local orbital (FPLO) code. The monoclinc (C2/m) NMSO consists of honeycomb layers (Mn2SbO6)3- formed by the 2:1 ordering of Mn and Sb, which then form honeycomb patterns. The results of our calculations using generalized gradient approximation (GGA) as the exchange-correlation potential confirmed the oxide is an anti-ferromagnet with a direct band gap of 0.38765 eV. The band gap is contributed by the Mn-3d state in valence band and Sb-5s states in conduction band. The crystal and band structures were affected by the geometry optimization. Oxides such as NMSO garner immense interest from researchers due to their potential applications as high-energy storage devices.
Keywords: Honeycomb layered oxides, monoclinic, antiferromagnet, direct band gap, energy storage device
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Abstract Number: ANPA2024-N00028 Presenting Author: Pawan Joshi Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur 44613, Kathmandu, Nepal Title: Electronic and Thermoelectric Properties of Kagome Rb2Pt3S4 Location: Poster Presentation Show/Hide Abstract We performed the theoretical investigation of electronic and thermoeletric properties of a kagome material Rb2Pt3S4 based on density functional theory using the full potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) method with in the frame work of GGA and TB-mBJ exchange-correlation potential. From the electronic structure study, we found that Rb2Pt3S4 is an indirect band gap semiconductor with an energy gap 1.29 (1.87) eV using GGA(TB-mBJ). The semi-classical Boltzmann transport theory were employed to study the charge-carrier transport behavior and temperature dependent thermoelectric (TE) properties, including Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor, and figure of merit. Our reported results show that the material is beneficial for n-type TE material at high temperature as n-type transport parameters are greater than the p-type ones. The maximum values of the figure of merit for the title compound were computed corresponding to optimum n(p)-type doping concentrations. These important parameters are noteworthy to explore experimental works for real time application of studied compound as TE material.
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Abstract Number: ANPA2024-N00027 Presenting Author: Meenashree Khanal Presenter's Affiliation: Department of Physics, Amrit Campus, Tribhuvan University Title: Effect of UV light on impedance spectrum of the pure and Ag-doped ZnO film Location: Poster Presentation Show/Hide Abstract This work reports the impedance spectrum analysis of the undoped and silver-doped ZnO film before and after UV treatment. UV light of wavelength 365 nm was exposed on ZnO and Ag-ZnO films and their impedance data was recorded using a Hioki LCR meter in the AC frequency range of 100 Hz to 10,000 Hz. Herein, the spin coating method was employed to synthesize undoped and 1% to 5% Ag-doped ZnO films. The structural, optical and UV light sensing properties of as-prepared films were investigated employing XRD, UV-Vis spectrophotometer, and FTIR techniques. The X-ray diffraction pattern results demonstrated the polycrystalline, hexagonal wurtzite nature of ZnO of crystallite size ~25.4 nm and Zn-O bond length of 1.95 Å . The results also showed a gradual decrease in size from 26.44 nm for 3% and 24.19 nm for 5% Ag-doped ZnO film. On the other hand, the band gap calculated from observed transmittance showed the average band gap of ZnO was 3.22 eV. The impedance spectrum analysis of ZnO before and after UV exposure showed a decrease in the diameter of the Nyquist arc which indicates an increase in the film’s conductivity. These characteristics of ZnO are found to be useful for potential semiconductor devices and optical sensors.
Keywords: ZnO film, Ag-ZnO, spin coating, UV light, impedance spectrum
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Abstract Number: ANPA2024-N00026 Presenting Author: Manisha Rai Presenter's Affiliation: Student Title: STUDY ON POROUS Al DOPED ZnO THIN FILM AS A GLUCOSE BIOSENSOR Location: Poster Presentation Show/Hide Abstract This work reports on the development of a novel and efficient non-enzymatic porous Al-doped porous ZnO glucose sensor. The thin film of ZnO with different percent of Al doping were synthesized by using spin coating method, on the steel substrate. The prepared sample were characterized by optical study and nyquist plot. Cyclic voltammetry was used to analyze and optimize the electrochemical performance. CV measurements showed that, 2% Al-doped thin film showed better resultant current in the basic medium. Additionally, different percentages of PEG were added into the ZnO precursor solution to fabricate the porous ZnO film. The 6% PEG was optimized to perform the best electrochemical activity. The 2%Al-ZnO/steel sample showed a 62.5µM low detection limit (LOD); however, porous 6%PEG+2\%Al-ZnO/steel showed an improved LOD of 0.122µM. Nyquist plots showed that the enhanced performance of of 6%PEG+2%Al-ZnO/steel sample is due to improved charge transfer resistance.
Keywords : Non-Enzymatic, Biosensor, ZnO, Thin Film
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Abstract Number: ANPA2024-N00025 Presenting Author: Kedar Nath Jaiswal Presenter's Affiliation: Central Department of Physics,Kirtipur,Kathmandu Title: Electronic and Optical Property Tuning by Chlorine Doping on Oxyhalide Bi2LaO4I Location: Poster Presentation Show/Hide Abstract Electronic and Optical Property Tuning by Chlorine Doping on Oxyhalide Bi2LaO4I
Kedar Nath Jaiswal1,2, Sarita Lawaju1,2 and Madhav Prasad Ghimire1,3,4*
1Central Department of Physics, Tribhuvan University, Kirtipur, 44613 Kathmandu, Nepal
2Condensed Matter Physics Research Center (CMPRC) Butwal, Rupandehi, Nepal.
3Leibniz - IFW Dresden,Helmholtzstr. 20, 01069 Dresden, Germany
4Faculty of Science Education, Jeju National University, Jeju 63243, Republic of Korea
*Corresponding author: madhav.ghimire@cdp.tu.edu.np
ABSTRACT
Layered Bismuth oxyhalides are promising photocatalysts used for the degradation of organic molecules as well as for water splitting reaction. The photocatalytic activity of pristine layered Bi2LaO4I as well as Cl doped Bi2LaO4I were investigated on the basis of full-potential local orbital (FPLO), adopting both the scalar relativistic formulations within the framework of the generalized gradient approximation(GGA) and modified Becke and Johnson (mBJ) as exchange-correlation potential. Our calculations confirm the increase in band gap of Bi2LaO4I from 1.0811eV to 1.1437 eV (within GGA) and from 1.8784 eV to 1.8848 eV (within GGA-mBJ) when Cl is doped. Further, we conclude that the optical band gap of these oxyhalides can be tuned through concentration of Cl doped in them.
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Abstract Number: ANPA2024-N00024 Presenting Author: Dipak Oli Presenter's Affiliation: Tribhuvan University, Kathmandu Nepal Title: FIRST PRINCIPLES STUDY OF UNDOPED AND HALOGEN DOPED ZnO MONOLAYER Location: Poster Presentation Show/Hide Abstract Addition of impurities in pristine 2D materials has been one of the recent trends. The physical properties of materials have been greatly enhanced by doping with foreign elements and creating vacancies. In this work, we studied structural, electronic, and magnetic properties of undoped and halogen (F, Cl, Br) doped ZnO monolayer, whereas one Zn-atom is replaced by a halogen atom. Computation was done using Density Functional Theory in VASP computational tool. The PBE and PBE+U functionals were employed in order to study the exchange correlation functional. The band gap of pure ZnO was found to be 1.67 eV and 2.61 eV while employing PBE and PBE+U functionals respectively. However, the band gap was found to be sharply decreased, suggesting that the conductivity of the doped monolayer increases. Further, analyzing the Density of state (DoS) and projected Density of state (PDoS) of our systems, it was found that the halogen doped ZnO behaves like a magnetic material.
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Abstract Number: ANPA2024-N00019 Presenting Author: Samjhana Dahal Presenter's Affiliation: Tribhuvan University Title: GERMINATION AND SEEDLING GROWTH ENHANCEMENT OF TIMUR SEED (Zanthoxylum armatum) BY USING COLD ATMOSPHERIC PRESSURE PLASMA Location: Poster Presentation Show/Hide Abstract Timur is a plant native to the Himalayan region and it is valued for its intense citrusy and peppery flavor, used in culinary and traditional practices. In this work, we have used gliding arc discharge for direct treatment of the Timur seed (Zanthoxylum armatum) and used plasma-activated water, prepared by cylindrical dielectric barrier discharge and gliding arc discharge, to irrigate the plants, aiming to enhance germination and seedling growth. The plasma sources are characterized through electrical and optical characterization methods. From spectrometer, electron temperature of cylindrical dielectric barrier discharge and gliding arc discharge is found to be 1.41 eV and 1.66 eV with plasma density found to be 8.17 × 10^18 m^ −3 and 5.48 × 10^17 m ^−3 , respectively. Plasma treatment increases the temperature, total dissolved solids, electrical conductivity, and oxidation-reduction potential of the plasma-activated water with the activation time; however, the potential of hydrogen
decreases. In addition, it has been observed that nitrate concentration is notably higher than nitrite concentration. It has been observed that the direct application of plasma on Timur seeds results in changes to the seeds, particularly in their surface properties and wettability. The results showed that the wettability of seeds using two minutes (min) plasma-activated water increases the most compared to the untreated seeds and other treatment times. Although germination enhancement of the Timur seeds is not achieved in the laboratory condition, plasma-activated water positively impacts root and shoot growth, as well as in the retention of chlorophyll content (or greenness) of leaves. A treatment time of four minutes using cylindrical dielectric barrier discharge and two minutes using plasma jet
is found most favorable. The positive impact of plasma on Timur plants can be studied further to enhance germination, seedling growth, and ultimately, fruit yield, making it viable for agricultural applications in real field conditions.
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Abstract Number: ANPA2024-N00022 Presenting Author: Damodar Neupane Presenter's Affiliation: Patan Multiple Campus, Tribhuvan University Title: Comparative Study of Titanium Dioxide and Lysozyme-Doped Titanium Dioxide Nanoparticles for Enhanced Photocatalytic Degradation Location: Poster Presentation Show/Hide Abstract Titanium dioxide (TiO2) and lysozyme-doped titanium dioxide (L-TiO2) nanoparticles were synthesized via a hydrothermal method. Structural, morphological and optical properties of L-TiO2 were compared with synthesized TiO2 nanoparticles prepared without lysozyme. X-ray diffraction (XRD) patterns revealed the dominance of the anatase phase and presence of rarely found α-PbO2 structure in L-TiO2, while TiO2 exhibited anatase, brookite and rutile phases. Both nanoparticles possess fewer structural defects, potentially enhancing mechanical properties. Fourier transform infrared spectroscopy (FTIR) identified specific chemical bonds or functional groups associated with lysozyme addition. UV-Vis spectroscopy indicated a decrease in the band gap energy from 3.21 to 2.94 eV upon the incorporation of lysozyme on titanium dioxide nanoparticle. High Resolution Transmission Electron Microscopy (HR-TEM) analysis confirmed an average particle size of 9.18 nm for L-TiO2 and 22.97 nm for TiO2 nanoparticles, consistent with XRD results. Field Emission Scanning Electron Microscopy (FE-SEM/EDS) analysis showed agglomerated fine particles with the presence of Ti, O, and C elements. L-TiO2 nanoparticles showed enhanced photocatalytic performance, degrading Methylene Blue dye to 97% with a rate constant of 0.039 min-1 and Methyl Orange to 81% with a rate constant of 0.019 min-1 within a 90 minute time interval under UV irradiation at 365 nm, compared to 90% and 76% degradation, using TiO2 nanoparticles. Optimization studies revealed that the best degradation efficiency was achieved at a dosage of 0.1 g. Additionally, the synthesis process produced TiO2 polymorphs, including α-PbO2-type TiO2, which showed superior photocatalytic activity. L-TiO demonstrated superior reusability compared to TiO2 for both dyes, maintaining consistent degradation on repeated cycles. Overall, the study highlights the potential of L-TiO2 nanoparticles for environmental applications.
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Abstract Number: ANPA2024-N00021 Presenting Author: Bikal Khanal Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: A Review on Machine Learning for Design, Discovery and Properties of Energy Materials Location: Poster Presentation Show/Hide Abstract Materials design and property prediction based on structure have recently become an important area in energy materials research. This marks a transition in exploration methodologies, moving away from traditional approaches often constrained by time-consuming empiricism and experiments, resulting in slow progress in research and development. An innovative strategy is considered necessary to accelerate this process by leveraging new technologies for discovery and advancement. A new paradigm involving the utilization of Artificial Intelligence (AI) and Machine Learning (ML) in materials research is emerging. This approach centered on data facilitates the engineering of new energy materials and the prediction of their properties without depending on conventional techniques. Several studies show advancements in materials engineering, design improvements, the utilization of energy materials, and more by deploying ML. This article revisits the established three paradigms of energy materials research and contrasts them with this emerging fourth paradigm. It delivers a concise outline of ML methodologies, databases utilized for energy materials, and a comparative evaluation of various ML models to elucidate the present research trajectory. The advantages and constraints presented by AI and ML in the design and advancement of different energy materials such as Li-Ion batteries, photovoltaic materials, CO2 capture materials, among others are demonstrated. Finally, a number of successful cases are outlined where ML has demonstrated its reliability as a research tool in the research and development of energy materials.
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Abstract Number: ANPA2024-N00020 Presenting Author: Saroj Pandeya Presenter's Affiliation: Central department of Physics Title: OBLIQUE PROPAGATION OF DUST-ION ACOUSTIC WAVES IN 3D3V QUANTUM MAGNETIZED DUSTY PLASMA WITH ELECTRON PRESSURE ANISOTROPY Location: Poster Presentation Show/Hide Abstract Due to the wide range of growing applications, the understanding of wave characteristics in magnetized quantum dusty plasma is inevitable for unfolding the mystery of dense astrophysical environments, laser-produced plasma, micro and nano-scale physics. Moreover, the emerging potential of quantum information science utilizing ultra-cold quantum plasma has gained significant interest. In this study, we employ the quantum hydrodynamic model (QHM) and reductive perturbation technique to investigate features of nonlinear oblique propagation of dust-ion acoustic waves (DIAWs) in account of electron pressure anisotropy. It is found that solitary wave structure including phase velocity, solitary wave's width, and amplitude are affected by the pressure anisotropy and obliqueness of wave propagation. The magnitude of the magnetic field affects the width of solitary waves. The decaying of solitary wave energy as the function of time indicates that the waves get damped as time evolves. Moreover, we have compared our analytical results with the results obtained from the finite-difference method and estimated the percentage deviation, which is less than 10%. Our findings provide valuable insights into the propagation of dust-ion acoustic waves, particularly in astrophysical dusty plasmas.
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Abstract Number: ANPA2024-N00034 Presenting Author: Pratiksha Khanal Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur 44613, Kathmandu, Nepal Title: Predicting the Lattice Parameters of Transition Metal Halides - MXn via Machine Learning Location: Poster Presentation Show/Hide Abstract Transition metal halides have been studied extensively because of their wide range of tunable electrical, magnetic, and topological properties that come from their unique crystal structure. Knowing lattice parameters, a building block of every crystal structure, enriches filtering materials properties like structure stability, electronic structure, magnetic ordering, and thus materials discovery. Here, we present machine learning models: Random Forest Regression (RFR) and Gradient Boosting Regression (GBR) for predicting lattice parameters (a,b,c) of transition metal halides - Mxn with 238 samples based on the properties of their constituent atoms. The metrics R2 score and mean absolute error (MAE) are used for validation of model performance yielding the overall values 0.80±0.09(0.82±0.14) and 1.33±0.64(1.12±0.35) using RFR(GBR) respectively. We have observed that the predictive strengths of both models are quite comparable but as a whole, GBR model is found to be more favorable than RFR. These findings are expected to be useful to experimentalist and theorist in characterizing and studying various properties of Mxn system.
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Abstract Number: ANPA2024-N00018 Presenting Author: Ramesh Khanal Presenter's Affiliation: Student Title: PLASMA-WALL INTERACTION MECHANISM AND DUST PARTICLES CHARGING FOR MAGNETIZED PLASMA EXPOSED WITH TUNGSTEN AND CARBON ELECTRON EMITTING SURFACES Location: Poster Presentation Show/Hide Abstract The understanding of plasma-wall transition characteristics is crucial when the quasineutral plasma interacts with a material surface via a non-neutral plasma sheath which determines the flow of particles flux and energy towards the surface. This interaction determines the lifetime of plasma-facing materials. In this study, we have used kinetic theory to investigate the magnetized plasma-wall interaction and dust charging model in the presence of secondary electron emission from material surfaces (tungsten and carbon). The kinetic Bohm sheath condition has been extended in the presence of secondary electron emission and it is found that ion flow at the presheath-sheath boundary and wall potential get affected by the flux of electron emission. The variation of sheath potential, particle densities, and energy of positive ions towards the surface are significantly changed by the concentration of secondary electron emission. The flow of ion's energy toward the surfaces determines the magnitude of ion particle reflection, absorption, and sputtering yield for the selected materials. Furthermore, the sputtered tungsten and carbon dust particles in plasma are getting charged and the evolution of dust charge in the plasma-wall transition region and dust particle levitation have been systematically presented.
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Abstract Number: ANPA2024-N00017 Presenting Author: Nisha Kaucha Presenter's Affiliation: Patan Multiple Campus Title: CHARACTERIZATION OF COLD ATMOSPHERIC PLASMA: PRODUCTION OF REACTIVE SPECIES AND ITS ANTIBACTERIAL PROPERTIES. Location: Poster Presentation Show/Hide Abstract The antibacterial capabilities of cold atmospheric plasma are significantly influenced by the presence of reactive species in the plasma discharge. The cold atmospheric plasma has multiple applications in biomedicine. Its applications in the contemporary world are rapidly growing and now included sterilization, disinfection, cancer treatment, and many more. In light of this, the primary focus of this dissertation was on the creation of reactive species and study antibacterial properties of plasma, with the cold atmospheric plasma (CAP) being characterized through the use of electrical and optical techniques. Oscilloscope helped to estimate value of electron density, whereas, a spectrometer measured the nitrogen (III) spectral lines with varying wavelengths and intensities. It was useful for figuring out the plasma discharge's electron temperature. To calculate the electron temperature, one used the Boltzmann plot approach. Electron temperature and density were useful in determining the plasma's performance. Gliding arc discharge (GAD), which used 'air' as process gas and had a flow rate of 15 lpm, a high voltage power supply of 12 KV, and an operating frequency of 50 Hz, was used for CAP discharge.\\
Two separate bacterial samples were obtained and cultured in Nutrients agar for a few days in order to examine the antibacterial properties: one gram negative sample, Escherichia coli-ATCC 25923, and the other gram positive sample, Staphylococcus aureus-25922. After that, it was treated with plasma for different amounts of time, which aided in the establishment of a Zone of inhibition in treated areas demonstrating the antibacterial efficacy of plasma. Additionally, well water samples were subjected to cold plasma treatment to study Physico-chemical parameters.
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Abstract Number: ANPA2024-N00016 Presenting Author: Kashi Ram Panday Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur Title: ADSORPTION OF KHARIDHUNGA(TALCSTONE)AND KAMEROMATO (CLAY) IN DISTILLED WATER AND ACETONE Location: Poster Presentation Show/Hide Abstract Nanoparticles are common in nature and are the subject of research in many areas, including chemistry, physics, geology, and biology. Nanoparticles are of great interest because of the transition between bulk materials and atomic or molecular structures, they display behaviors that are not observed at either size. A study of FTIR and UV-Vis of kameromato and kharidhunga adsorbed in water and acetone has been carried out in this research work. For the FTIR study, kharidhunga and kameromato powder were dried in a dry air oven. After being mixed with the proper amounts of water and acetone respectively, the sample was brought in for the sonication procedure. For UV-Vis, the solution was further diluted in acetone, and for FTIR, the sample's remnant was allowed to dry naturally. The FTIR spectra of pure kharidhunga showed Mg-OH stretching and Si-O-Si symmetric stretching at 3675 cm-1 and 664 cm-1, respectively, indicating the existence of magnesium and silicate. The presence of aluminum and silicate bonding in our kameromato sample was further confirmed by the Al-OH-Al vibration and Si-O-Si stretching at 909 cm-1 and 673 cm-1 respectively, in the kameromato FTIR spectrum. In the IR spectrum of Kharidhunga in acetone, a weak peak at wavenumber 1423 cm-1 indicates the presence of C=O bonds which confirms the absorption of acetone by Kharidhunga. The UV spectrum of kameromato in acetone exhibits a prominent absorbance peak at 275 nm, demonstrating that the kameromato sample has absorbed acetone. This work will contribute to the manufacture of health-friendly cosmetics.
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Abstract Number: ANPA2024-N00015 Presenting Author: Aman Kumar Rai Presenter's Affiliation: Tribhuwan University Title: ION FLOW, SHEATH CHARACTERISTICS, AND DUST DYNAMICS OF LUNAR DUSTY PLASMA WITH SUPERTHERMAL ELECTRONS Location: Poster Presentation Show/Hide Abstract In space dusty plasma (lunar dusty plasma), the emission of electrons from the lunar surface due to solar UV radiation significantly affects the characteristics of the plasma sheath formed at the lunar surface, which is crucial to understanding the dust charging mechanism and dust dynamics of lunar dusty plasma. In this work, a steady-state collisionless ion fluid model is used for lunar dusty plasma in the presence of solar wind superthermal electrons. All the plasma parameters used during the numerical execution are consistent with the lunar dusty plasma environment. The extended form of the modified Bohm sheath criterion has been derived and it is found that ion flow at the sheath boundary and the evolution of equilibrium dust charge are significantly influenced by superthermal index of electrons, solar zenith angle, and solar wind conditions. The effect of photoelectron emission from the lunar surface and solar zenith angle on surface potential has been graphically illustrated. The electrons and positive ions are found to be decreased towards the surface; however, the decrement rate for ions is much slower than that of electrons. Moreover, the choice of superthermal electrons affects the temporal evolution of dust charge, dust charging on sheath region, dust levitation, and dust dynamics as well.
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Abstract Number: ANPA2024-N00014 Presenting Author: BINAYA CHANDRA POKHREL Presenter's Affiliation: PMC, TU, Nepal Title: Deciphering Atomic Polarization Effects on Energy Dynamics and Output Voltage in Proton Exchange Membrane Fuel Cells Location: Poster Presentation Show/Hide Abstract The impact of various parameters such as atomic polarizability, infrared frequency, and polarizability distance on Proton Exchange Membrane Fuel Cells (PEMFCs) performance during the interaction of hydrogen and platinum is explored with first order perturbation theory and theories of electrochemistry in this article. This comprehensive analysis reveals significant insights into energy change, actual potential variation, and current-voltage relationships for the cell. It is found that energy shift in the PEMFC system increases with infrared frequency and atomic polarizability, indicating a higher tendency for ionization in particular thermal energy (exothermic energy; virtual photon) and polarizability conditions. Moreover, we find there is a crucial role of atomic polarizability to determine actual potential generated within the anode of PEMFC. The analysis suggests higher polarizability values generate low or zero potential. This study depicts the inverse correlation between output voltage and current density indicating the limitations of PEMFCs under higher load conditions, highlighting the necessity for optimization in cell designing and other operational parameters. In conclusion, this study indicates the loop for the optimization of PEMFC performance, offering combo, quantum and electrochemical, basis for the fuel cell technology in practical applications.
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Abstract Number: ANPA2024-N00023 Presenting Author: Dikshya Chand Presenter's Affiliation: Physics, M.Sc., Patan Multiple Campus Title: Development of Non-Enzymatic Glucose Biosensor using Cobalt Oxide Thin Film Location: Poster Presentation Show/Hide Abstract Development of Non-Enzymatic Glucose Biosensor using Cobalt Oxide Thin film
Dikshya Chand1, Manisha Rai1, Leela Pradhan Joshi2, Shankar Prasad Shrestha1
1Physics Department, Patan Multiple Campus, Lalitpur, Tribhuvan University, Nepal
2Physics Department, Amrit Campus, Tribhuvan University,
Email: shankarpds@yahoo.com
In the present work, cobalt oxide thin films were fabricated via a spray pyrolysis technique and studied their application in glucose detection using cyclic voltammetry (CV). Cobalt oxide thin films were deposited on steel substrate at 150±50 degree C. The structural properties of cobalt oxide thin films were studied using X-ray diffraction. The electrochemical performance of the cobalt oxide thin films for glucose detection was evaluated using cyclic voltammetry. The cobalt oxide based sensor exhibited a significant electrochemical response to glucose. Herein, we optimized various factors like concentration of electrolyte, deposition temperature, number of coatings and scan rate. The result showed that 0.7 M concentration of KOH solution, deposition temperature of 150 ±50 degree C, 12 coated layer and scan rate of 40 mV/s as the best result condition. These findings suggest that spray deposited cobalt oxide thin films are promising candidates for non-enzymatic glucose sensors, offering a potential pathway for developing cost-effective glucose monitoring devices.
Keywords: Cobalt oxide, Thin films, Spray pyrolysis, Cyclic voltammetry, Glucose detection, Non-enzymatic sensor.
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Abstract Number: ANPA2024-N00035 Presenting Author: Pratima Khadka Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur 44613 Kathmandu ,Nepal Title: Machine Learning Driven Prediction of Formation Energy and Band Gap of AxMyM'zO6 Oxides Location: Poster Presentation Show/Hide Abstract Machine learning (ML) is an efficient method in the discovery of new materials due to its lower computational costs as compared to conventional density functional theory (DFT) and laboratory trials. In this work, we are using ML approach to predict the formation energy and band gap of AxMyM'zO6 (x=1,2,3 & y,z=1,2 ; y+z=3) perovskite material. A dataset of 350 compounds is collected with following features: lattice parameter, band gap, formation energy, total magnetization, energy above hull, density, and periodic table properties. We are using four ML models: Random forest (RF) regressor, Gradient boosting regressor (GBR), Support vector regression (SVR) and CatBoost regressor (CBR). Root mean squared error (RMSE) and R-squared value are evaluated to determine the performance of different models. The contribution of different features for formation energy and band gap prediction are also plotted from RF model. It is found that CBR model has achieved maximum performance in prediction with R-squared and RMSE: (0.83 and 0.41) and (0.44 and 0.69) for formation energy and band gap respectively. The properties of materials depends significantly on the magnitude of band gap. Formation energy is a determining factor of material's stability and synthesizability. So, ML can be used to assist DFT calculations for material discovery and its applications.
Keywords: Machine learning, Formation energy, Band gap, RF, CBR.
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Abstract Number: ANPA2024-N00037 Presenting Author: Chiranjib Mitra (Invited) Presenter's Affiliation: Indian Institute of Science Education and Research, Kolkata Title: Topological Photo-current and magnetization control in 3D Topological Insulators Location: In-Person Presentation, CDP Show/Hide Abstract Optical control of helicity-dependent photocurrent has also been studied in 3D topological insulators. Strong spin-orbit coupling and spin-momentum locking make this system unique for their applications. We observed that photocurrent can be controlled by exciting the sample with different circular and linear polarized light, yielding a polarization-dependent current density which can be fitted very well with a theoretical model. This photocurrent
can also be controlled with the help of photo-thermal gradient generated by the excitation light beam.
Enhancement and inversion of this photocurrent in presence of photo-thermal gradient for light incident on two opposite edges of the sample occur due to selective spin state excitation with two opposite (left and right) circularly polarized light in presence of the unique spin-momentum locked surface states.
We also present efficient spin to charge conversion (SCC) in the topological insulator and ferromagnetic thin films based heterostructure by using spin-pumping technique The SCC, characterized by inverse Edelstein effect length (kIEE) in the TI material, gets altered with an intervening Copper (Cu) layer, and it depends on the interlayer thickness. The introduction of Cu layer at the interface of TI and FM metal provides a new degree of freedom for tuning the SCC efficiency of the topological surface states. The significant enhancement of the measured spin-pumping voltage and the increased linewidth of ferromagnetic resonance absorption spectra due to the insertion of Cu layer at the interface indicate a reduction in spin memory loss at the interface that resulted from the presence of exchange coupling between the surface states of TI and the local moments of FM metal.
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Abstract Number: ANPA2024-N00038 Presenting Author: Deergh Bahadur Shahi Presenter's Affiliation: Patan Multiple Campus, Patandhoka, Lalitpur, Tribhuvan University, Nepal Title: Thickness Dependent Electronic Properties and Cleavage energy of Pt2HgSe3 Location: In-Person Presentation, CDP Show/Hide Abstract The size and thickness limitations of synthesized Jacutingaite (Pt2HgSe3) make it difficult to study its quantum properties, such as its dual-topological nature and large-gap quantum spin Hall state, through a layer-controlled mechanism. Although theoretical calculations have explored these properties in monolayers, experimental studies have been hindered by the challenges associated with size and layer number limitations during exfoliation. To investigate the quantum properties of Jacutingaite, we use a combination of mechanical exfoliation and plasma-assisted thinning to obtain very few layers, and potentially mono- or bilayers. Our goal is to study the electronic properties of layer-controlled (mono to few layer) Jacutingaite by fabricating quantum Hall devices and conducting ARPES studies. We additionally perform density functional theory calculation to study the electronic properties and the cleavage energy of mono to few layer by using the full-potential local-orbital code. The cleavage energy of mono, bi and tri-layers are found to be within 0.46-0.54 Jm-2 which is closely comparable with graphite. Metal-insulator-transition are observed with increase in thickness.
This work is supported by the Brain Pool program (No. RS-2023-00304344), National Research Foundation of Korea and University Grants Commission (CRG-78/79 S&T-03), Nepal.
Keywords: Jacutingaite, mechanical exfoliation and plasma-assisted thinning, Density functional theory, Cleavage energy, Topological phase transition
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Abstract Number: ANPA2024-N00039 Presenting Author: Dipak Bhattarai Presenter's Affiliation: PhD scholar, Institute of Science and Technology, Tribhuvan University, Nepal Title: Electronic Structure and Anomalous Hall Conductivity of Magnetic Weyl Ferromagnet Bi2TeMnI2 Location: In-Person Presentation, CDP Show/Hide Abstract Electronic Structure and Anomalous Hall Conductivity of Magnetic Weyl Ferromagnet Bi2TeMnI2
Dipak Bhattarai1, and Madhav Prasad Ghimire1,2
1 Central Department of Physics, Tribhuvan University, Kirtipur, 44613, Kathmandu, Nepal
2 Leibniz - IFW Dresden, Helmholtzstr-20, 01069 Dresden, Germany
Email: dipak.bhattarai@trc.tu.edu.np
Abstract:
Weyl semimetals (WSM) represent a category of crystalline materials distinguished by their exceptional electronic characteristics, defined by the existence of Weyl fermions [1]. They are intriguing for electronics and spintronics due to their unique band structure with Weyl points, leading to exotic phenomena such as chiral anomaly and Fermi arcs [2]. In search for new WSM, we consider magnetic doping (i.e., Mn) to the Te site of BiTeI. For this calculations, we use full-potential local orbital (FPLO) code [3] which is based on density functional theory. Our calculations for the parent compound BiTeI is nonmagnetic while the Mn substituted to the Te-site (i.e., Bi2TeMnI2) suggest a ferromagnetic ground state in optimized state with an effective magnetic moment of 3.41 μB per unit cell. Magnetic doping transforms BiTeI from narrow band gap semiconductor to a ferromagnetic WSM due to change in the electronic band topology. Our study confirms that Bi2TeMnI2 has 6 Weyl points around 100 meV above the Fermi level. The calculated intrinsic anomalous Hall conductivity is ~575 (Ω-cm)-1. Based on our calculations, we predict the Bi2TeMnI2 to be a promising candidate for high-speed electronics and spintronics device.
This work is supported by grants from TWAS-UNESCO (21-377 RG/PHYS/AS_G), Italy and University Grants Commission (CRG-78/79 S&T-03), Nepal. D.B. acknowledges the Nepal Academy of Science and Technology, Khumaltar, Nepal for PhD fellowship and Department of Science and Technology, Government of India for ISRF-2022 award.
References
1. X. Wan, A. M. Turner, A. Vishwanath, and S. Y. Savrasov, Phys. Rev. B 83, 205101 (2011).
2. Huang et al. Phys. Rev. X 5, 031023 (2015).
3. K. Koepernik, and H. Eschrig, Phys. Rev. B 59, 1743 (1999).
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Abstract Number: ANPA2024-N00040 Presenting Author: Mithilesh Kumar Jha Presenter's Affiliation: Ph.D Scholar, Central Department of Physics, TU, Kirtipur, Kathamndu, Nepal Title: Computational Study on Electrical Properties of NiPtCu Solid Ternary Alloy Location: In-Person Presentation, CDP Show/Hide Abstract Alloying is one of the commonly used tool in order to explore the new properties of elements. We generally explore six different types of properties of any material viz. - mechanical, thermal, optical, electrical, magnetic and chemical properties. The properties of materials may vary with shape and size. The materials in bulk shows one type of property whereas in nano-particle or films it may show different properties. In this study, we are focused on exploring the electrical properties of solid ternary alloy NiPtCu2. We used Quantum Espresso, a freeware to investigate the electrical properties. We designed the solid ternary alloy in bulk form and calculated the cut off energy, pseudopotential, brillouin zone, density of state (DOS) and band structure of the considered molecules. The detailed results of this solid ternary alloy will be comprehensibly presented.
Key words: Solid ternary alloy, bulk form, pseudopotential, brillouin zone and band structure.
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Abstract Number: ANPA2024-N00041 Presenting Author: Sarita Lawaju Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: Layered Honeycomb Oxides: Possible Candidates for Energy Storage Location: In-Person Presentation, CDP Show/Hide Abstract Honeycomb layered compounds are structures having different hexagonal arrays forming the honeycomb layers. This study focused on the mixed metal honeycomb oxides of type A3MM’BO6 [A = Na, Li, Cu; M = transition metals, M’ = Mg, Cu, Zn; B = Bi, Sb, Ru] which are also known as rock-salt superstructures and are extensively studied for their structure, magnetic, electrochemical, photocatalytical, quantum properties, etc. The oxides Na3NiMgSbO6 and Na3NiZnSbO6 have been synthesized by high temperature solid state reactions. Field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), powder X-ray diffraction (PXRD) followed by Rietveld refinements and Raman measurements were carried out to study their surface morphology and structural properties. The surface morphology showed the homogeneous crystallites formation whereas EDS confirmed the ratio of Ni, Mg/Zn, Sb to be 1:1:1. The structural refinements of PXRD patterns of these oxides revealed their monoclinic symmetry [Space Group: C2/m (12)]. These oxides have quasi two-dimensional Na+ ions in the interlayer region separated by the honeycomb layers (NiMgSbO6)3- and (NiZnSbO6)3- formed in ordering of the atoms in above mentioned ratio (1:1:1). The Raman peaks further support the formation of oxides and presence of respective metal-oxide bonds and hence successful synthesis of these oxides. The lattice information obtained from the structural refinements were carried out for further density functional calculations to study their electronic and magnetic properties. The scope of this ongoing work is to explore the potential application of honeycomb layered oxides as energy-storage devices.
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Abstract Number: ANPA2024-N00043 Presenting Author: Ram Prasad Regmi (Invited) Presenter's Affiliation: National Atmospheric Resource and Environmental Research Laboratory (NARERL), Central Department of Physics, Tribhuvan University, Kathmandu, Nepal. Title: Air Pollution Transport and Formation of Pollutant Fields Over the Major Urban Centers in the Complex Terrain of Nepal Himalayan: Prospects of Ensuring National Ambient Air Quality Standard Location: In-Person Presentation, CDP Show/Hide Abstract Unacceptable levels of air pollution in and around the urban centers like Kathmandu Valley and Lumbini that accommodate large proportion of national population and world heritage sites is of serious concern. Development of air pollution control system for these regions, located in the complex terrains of Nepal Himalaya, remained a challenge. Resolving the meteorological flow fields, air pollution emission activities and the dynamics of pollutants down to kilometer scale horizontal grids, present study has paved the way to ensure the national air quality standard in and around these urban centers. Meteorological flows and air pollution dynamics over these regions have been numerically simulated and are verified with field observations. The study reveals that air pollution dispersion power of both the regions, typically determined by the prevailing meteorological conditions, is very poor, particularly, during the long dry season. Present emission loadings into the immediate atmosphere of both the Kathmandu and Lumbini region are far beyond their carrying capacities. The National Ambient Air Quality Standard can be met by limiting the emissions from domestic, transport and industrial sectors, respectively, to 20, 30 and 40% of the current emissions over the Kathmandu valley and 50, 50 and 30% for Lumbini region with respect to the particulate pollutant PM2.5.
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Abstract Number: ANPA2024-N00044 Presenting Author: Lok Nath Sharma Presenter's Affiliation: Tribhuvan University Title: Ionospheric variations during the geomagnetic storms of March and April 2023 in Jeju Island, South Korea Location: In-Person Presentation, CDP Show/Hide Abstract The reconnection between the Interplanetary Magnetic Field (IMF) and the Earth’s magnetic field is the main driver of solar energy input to generate geomagnetic storms. In this work, we employ data from the Global Ionospheric Radio Observatory (GIRO) to study the effects of the March and April 2023 geomagnetic storms on ionospheric Total Electron Content (TEC) and F2 layer critical frequency (foF2) over the Jeju Island, South Korea. We investigate the possible ionospheric connection to OMNIWeb solar wind data through cross-correlation and continuous wavelet transforms (CWT) analyses. TEC and foF2 show a positive correlation above 0.9 to solar wind proton density (Nsw), and without time-lag during both storms. On the other side, during the storm of March 2023, TEC and foF2 show a negative correlation of 0.8 to the IMF By component with a time-lag of one hour, while the IMF Bz component and the geomagnetic SYM-H index show a negative correlation of 0.85 and 0.95, respectively, both without time lag. Conversely, during the storm of April 2023, the correlation of the IMF Bx component to TEC and foF2 are positive with a value of 0.7, and with a time-lag of 2.4 hours, while the IMF By and Bz components show a negative correlation to SYM-H above 0.9, both with absence of time-lag. These results show the significant fluctuations in ionospheric parameters over Jeju Island, South Korea and emphasizes the sensitivity and importance of ionosphere to space weather monitoring for understanding and mitigating the detrimental effects on communication and navigation systems.
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Abstract Number: ANPA2024-N00045 Presenting Author: Madhu Sudan Paudel Presenter's Affiliation: Department of Physics, Tri-Chandra Multiple Campus, TU Title: Seasonal Tropopause Dynamics over Nepal from 2022 to 2023: Insights from GNSS-RO Observations Location: In-Person Presentation, CDP Show/Hide Abstract ABSTRACT
Global Navigtion and Satellite System-Radio Occultation (GNSS-RO) is the robust method for monitoring the Earth’s atmosphere utilizing the refracted GNSS radio signal. Constellation Observation System for Meteorology, Ionosphere and Climate-2 (COSMIC-2) is one of the GNSS-RO satellite missions providing the bunch of information, which enables us to explore the characteristics of Earth’s atmosphere. It can provide the vertical profile of the atmospheric thermodynamic variable globally with resolution better than 1 km. The GNSS-RO data features the long-term stability, continuous in all types of weather condition along with very high precision and accuracy. In this pilot project, we are going to study the tropopause dynamics within the periphery of the Nepal, from longitude: 79◦E to 89◦E and latitude: 26◦N to 31◦N, using the data from COSMIC-2 mission from April 01, 2022 to March 30, 2023, by dividing into four seasons; March-April-May, June-July-August, September-October-November and December-January-Februry. For data extraction, we use the netCDF4 and Pandas and for the visualization and statistical analysis, we use the Matplotlib, Basemap, Scipy, Scikit-learn, libraries of the Python. The vertical profile of temperature, penetration depth and tropopuse height is studied. We use the Cold Point (CP) method and World Meteorological Organization (WMO) criteria to calculate the tropopasue height. The result obtained for tropopause height by both method for one year is compared with the COSMIC2 result. It is seen that the CP method agree more compare to the WMO method.
Keywords: GNSS-RO, COSMIC-2, Tropopause-dynamics, WMO.
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Abstract Number: ANPA2024-N00046 Presenting Author: Prakash Man Shrestha Presenter's Affiliation: Patan Multiple Camus, TU Title: Temporal variability of Solar Radiation and Atmospheric Turbidity on Jomsom on Wavelet approach Location: In-Person Presentation, CDP Show/Hide Abstract Population growth and industrialization effect on energy demands and air pollution levels. Knowledge of solar radiation is essential for an evaluation of solar energy system. Atmospheric turbidity factor is an important parameter for air pollution. The main aim of this project is to study temporal the variation of solar radiation and atmospheric turbidity on Jomsom (28.47o N, 83.83o E and 2,700 m above sea level)). The daily data of clearness index (KT) is received from the power achieve of NASA website for 12 years (2008 to 2019). The daily, monthly, seasonal and annual variations of solar radiation (Hg) and Linke turbidity (LT) are studied. The result exemplifies that during the whole study period, the maximum value of monthly average of LT is7.1 ± 1.7 in July, while the minimum value is 3.1 ± 1.4 in October. The results also show that TL is highly seasonal dependent with larger LT in monsoon ( 5.8 ± 1.6) and lower in post monsoon (3.1 ± 1.3). The average annual value of TOC exhibits slightly variable with a maximum in 2010 (277.52 DU ± 40.64 DU) and minimum in 2008 (267.19 DU ± 11.11 DU). The average value of Hg and LT during the whole study period are found 17.6 ± 7.0 MJ/m2/day and 5.1± 2.5 respectively. Continuous wavelet transform (CWT) is also used to analysis variation of Hg and LT. The power density of Hg greater than 24,000 (MJ/m2/day)2 is recorded from 2009 to mid of 2010 with period 8.5 year. The power density of LT between 1000 to1200 is recorded from 2016 to 2018 with period 8.5 year. This research work is beneficial for the further identification and analysis of Hg and LT at different places with same geography.
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Abstract Number: ANPA2024-N00047 Presenting Author: Purna Jyoti Shakya Presenter's Affiliation: Tribhuvan University Title: Magnetospheric Pc5 pulsation generated by interplanetary shocks during the geomagnetic storm of 22 June 2015 Location: In-Person Presentation, CDP Show/Hide Abstract We investigate magnetospheric Ultra low frequency (ULF) waves during the geomagnetic storm of 22 June 2015 from SuperMAG and OMNIWeb data. The Continuous Wavelet Transformation (CWT) analysis reveals the presence of Pc5 pulsations (150–600 s period) during the arrival of 2 interplanetary shocks, the first one at 5:45 UT and the second at 18:38 UT. Cross-correlation analysis shows magnetometer data are positively correlated with interplanetary magnetic field (IMF), AE index and Polar cap index. Similarly, solar wind density (Nsw), solar wind pressure (Psw), and solar wind velocity (Vsw), also show positive correlation. These observations indicate ULF waves are generated in the magnetosphere due to a sudden increase in solar wind density and velocity after the interplanetary shock, resulting in a gradual increase of dynamic solar wind pressure and a sudden compression from the Earth’s dayside magnetosphere.
Keywords: Ultra Low Frequency (ULF) waves, Pc5 Pulsations, Geomagnetic Storms, Magnetosphere.
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Abstract Number: ANPA2024-N00048 Presenting Author: Sanjay Lal Karna Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Nepal and Department of Physics, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal Title: Photocurrent Behavior in Sunceco PV Cell Modules with Irradiance and Temperature Variation in Nepal Location: In-Person Presentation, CDP Show/Hide Abstract The aim of this study is to explore how the photocurrent behaves in Sunceco PV cell modules under different levels of sunlight and temperatures, specifically in Nepal. For this this, we're using data on sunlight intensity from SOLARGIS, a reliable solar resource database. The PV cell we're focusing on is a 315 Wp polycrystalline module, known for having a short-circuit current of 9.371 A and an open-circuit voltage of 44.82 V, with an efficiency of 18.34%. This type of PV cell is commonly used in Nepal. Using Student package MATLAB's to analyzed the photocurrent characteristics of this PV cell module. The findings show a clear and consistent relationship between photocurrent, sunlight intensity, and temperature, which falls within the range of 9 to 19 A.
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FSU Sessions
Please look below for detailed schedule.
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Abstract Number: ANPA2024-N00080 Presenting Author: Daniel Autrey Presenter's Affiliation: Fayetteville State University Title: Welcome message by Department Chair Location: In-Person Presentation, Fayetteville Show/Hide Abstract |
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Abstract Number: ANPA2024-N00081 Presenting Author: Kenan Gundogdu Presenter's Affiliation: NC State University Title: Room Temperature Perovskite Superfluorescence and its Implications for Quantum Materials Location: In-Person Presentation, Fayetteville Show/Hide Abstract The formation of coherent macroscopic states and the manipulation of their entanglement using external stimuli are essential for emerging quantum applications. However, the observation of collective quantum phenomena such as Bose–Einstein condensation, superconductivity, superfluidity and superradiance has been limited to extremely low temperatures to suppress dephasing due to random thermal agitations. In this presentation we will talk about room-temperature superfluorescence (SF) in hybrid perovskite thin films. In SF an optically excited population of incoherent dipoles develops collective coherence spontaneously. This emergent collective state forms a giant dipole and radiates a burst of photons. Because electronic transitions dephase extremely fast, observation of SF in semiconductors is extremely rare and under high magnetic fields and at very low temperatures. Therefore, the discovery of room temperature SF in perovskites is very surprising and shows that in this material platform, there exists an extremely strong immunity to electronic dephasing due to thermal processes. To explain this observation, we propose that the formation of large polarons in hybrid perovskites provides a quantum analogue of vibration isolation to electronic excitation and protects it against dephasing even at room temperature. Understanding the origins of sustained quantum coherence and the superfluorescence phase transition at high temperatures can provide guidance to design systems for emerging quantum information technologies and to realize similar high-temperature macroscopic quantum phenomena in tailored materials.
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Abstract Number: ANPA2024-N00082 Presenting Author: Ghadendra Bhandari Presenter's Affiliation: West Virginia University Title: Study of spontaneous magnetization reversal in manganites thin films Location: In-Person Presentation, Fayetteville Show/Hide Abstract Manganite perovskite compounds have gained interest among strongly correlated electron oxides. These systems have complex phase diagrams originating from interactions among charge, spin, and lattice degrees of freedom. Thin films of manganite compounds: LaMnO3 and La0.7Sr0.3MnO3 were developed on SrTiO3 substrates. The ferromagnetic behavior dominates in these films, and is the only clear type of magnetism when large magnetic fields are applied. However, when small applied magnetic fields are used, another magnetic behavior is also observed. These two magnetic behaviors interact in interesting ways, resulting in inverted hysteresis loops and negative magnetization in zero field cooled curves. This behavior could have interesting implications for spintronics, sensors and other applications. This work is partially supported by NASA EPSCoR Award# 80NSSC22M0173.
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Abstract Number: ANPA2024-N00083 Presenting Author: Basu Dev Oli Presenter's Affiliation: Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA Title: Determining alloy composition in superconducting single-layer FeSe1−xTex on SrTiO3(001) Substrates by Machine Learning of STM/S Data Location: In-Person Presentation, Fayetteville Show/Hide Abstract Chemical pressure from the isovalent substitution of Se by a larger Te atom in the epitaxial film of iron chalcogenide FeSe can effectively tune its superconducting, topological, and magnetic properties. In this study, we investigated the effects of chemical pressure in single-layer FeSe1−xTex films grown on SrTiO3(001) substrates by molecular beam epitaxy. The substitution of Se by Te during epitaxial growth inherently leads to defects and structural inhomogeneity, as observed in scanning tunneling microscopy (STM) images, making it challenging to determine the alloy composition. We utilize machine learning to distinguish between Se and Te atoms in STM images of these films. First, defect locations are identified by analyzing spatially dependent dI/dV tunneling spectra using the K-means clustering method. After excluding the defect regions, the remaining dI/dV tunneling spectra are analyzed using the singular value decomposition method to determine the Se/Te ratio [1]. Our findings present an effective and reliable approach for determining alloy composition and atomic-scale electronic inhomogeneity in superconducting single-layer iron chalcogenide films.
[1] Oli et al., “Atomic-scale electronic inhomogeneity in single-layer iron chalcogenide alloys revealed by machine learning of STM/S data”, AIP Adv. 13, 105224 (2023)
This research is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (Grant Nos. DE-SC0017632 and DE-SC0021393).
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Abstract Number: ANPA2024-N00084 Presenting Author: Jett Wu Presenter's Affiliation: Fayetteville State University Title: Nano-Optimized Acetylcholinesterase Biosensor to monitor In Vitro and In Vivo Cholinergic Activity Location: In-Person Presentation, Fayetteville Show/Hide Abstract Acetylcholinesterase (AChE) inhibitors, such as chlorpyrifos, are widely used as pesticides and have been found to be harmful not only to pests but to humans as well. A common pest that affects crops is the bean beetle (Callosobruchus maculatus). We compared AChE activity obtained biochemically in bean beetles with AChE inhibition obtained electrochemically. The enzyme biosensor was constructed by immobilizing AChE onto MXene nanomaterials, which were attached to a conductive carbon cloth electrode surface. The presence of AChE inhibitors was then detected using this biosensor by electrochemical techniques, including differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). A toxicity test that was run over a 72- hour period showed bean beetles exhibited a mortality rate of 62.5% following exposure to chlorpyrifos (CPF). AChE activity was inhibited In vivo by CPF. The In Vitro biochemical assay revealed AChE was inhibited by CPF. Other pesticides such as glyphosate, acephate, and permethrin did not inhibit AChE compared to controls for in vitro assays. The biosensor positively detected AChE inhibition for chlorpyrifos, acephate, and glyphosate, all known to inhibit AChE. Permethrin did not inhibit AChE biochemically or electrochemically. While the waveforms of DPV and CV did give data that support the findings, the clearest data to support the findings came from EIS, which suggests a correlation between the concentration of organophosphates and peak current. Our findings confirmed that biosensors may be more sensitive to AChE inhibitors than biochemical assays alone.
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Abstract Number: ANPA2024-N00086 Presenting Author: Bhanu Ghimire Presenter's Affiliation: University of North Caroline at Charlotte Title: Meanderline Quarter Wave Plate Location: In-Person Presentation, Fayetteville Show/Hide Abstract Meanderline grids are basically wave retarder that functions as frequency selective surface (FSS) and changes optical polarization of the incident signal. In this paper, we demonstrate the behavior of quarter-wave retarder for medium-wave infrared (MWIR) spectrum. Conversion of linear polarization incident signal at 45-degree into circular polarization have been demonstrated using finite element electromagnetic simulation. Matrices used for analysis are average power reflectance for TE and TM modes, phase retardance, axial ratio and polarization conversion ratio.
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Abstract Number: ANPA2024-N00087 Presenting Author: Chandra M. Adhikari Presenter's Affiliation: Department of Chemistry, Physics and Materials Science, Fayetteville State University, Fayetteville, NC 28301, USA Title: Effect of cavity length in Mxene-based Fabry Perot interferometer Location: In-Person Presentation, Fayetteville Show/Hide Abstract Fabry-Perot interferometers (FPIs) are optical cavities made from two parallel high reflecting surfaces with a small transmissivity used for high-resolution spectroscopy. Tuning resonance peaks varying the cavity lengths in the FPI is of great interest in optoelectronic device applications such as optical filters. To achieve this, we first make use of Maxwell’s equation to theoretically investigate the relation of transmission and reflectance of a multilayer system and determine the transmission and reflection spectra of the distributed Bragg reflectors (DBR) in the system. Taking one of the most common lowest refractive index coating materials MgF2, and relatively high refractive index material TiO2, in layers of the system, the transmission and reflection spectra of the Fabry Perot interferometer constructed from them are evaluated. The same is evaluated by replacing one of the layers with Ti3C2 and Ti2C MXenes and graphene. The optical spectra are observed as a function of cavity length to analyze the resonant peak position variation with respect to the cavity length. We noticed that the DBR system blocks the wide range of the frequency band. The cavity formed between the two DBRs causes the formation of a transmission peak within the stop band whose position changes with the cavity length change.
This work is supported by the Department of Energy BES-RENEW award number DE-SC0024611.
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Abstract Number: ANPA2024-N00088 Presenting Author: Dipendra Dahal Presenter's Affiliation: nan Title: Resonance peak position tuning in Fabry Perot Interferometer. Location: In-Person Presentation, Fayetteville Show/Hide Abstract Making use of Maxwell’s equation, we have derived the relation of transmission and reflectance of a multilayer system which was used to determine the transmission and reflection spectra of distributed Bragg reflectors made up of TiO2/MgF2. We further evaluate the transmission and reflection spectra of the Fabry Perot interferometer constructed from the TiO2/MgF2, this DBR is later used to obtain the graphical representation of the spectra. In addition to this, we further analyze the resonant peak position variation with respect to the cavity length. We discuss the theory and the calculations to apply them in the optoelectronic devices.
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Abstract Number: ANPA2024-N00089 Presenting Author: Devi Lal Adhikari Presenter's Affiliation: Virginia Tech Title: Parity-Violating Electron Scattering as a Probe to Understand Fundamental Physics Location: In-Person Presentation, Fayetteville Show/Hide Abstract Parity is a discrete transformation that reverses the sign of a physical system’s spatial coordinates. It was long believed to be a universal symmetry until the mid-1950s, when it was found to be maximally violated in nuclear beta decay. Over the past three decades, the technique of parity-violating electron scattering (PVeS) has become increasingly precise. This technique involves measuring the asymmetry in the scattering of longitudinally polarized electrons off fixed targets. These asymmetries are sensitive to weak neutral current interactions, mediated by the Z boson, between electrons and quarks or between two electrons. This method provides a complementary approach to probing the limits of the electroweak theory, alongside direct searches for new physics at high energy scales in colliders. In this presentation, I will review the implications of the PVeS technique, highlight planned PVeS experiments for the next decade, and discuss how they will enhance our understanding of fundamental physics.
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Abstract Number: ANPA2024-N00090 Presenting Author: Trailokya Bhattarai Presenter's Affiliation: UNC Charlotte Title: Advancing Disinfection Technology: Solar-Powered UV LED Systems for Microbial Reduction Location: In-Person Presentation, Fayetteville Show/Hide Abstract UV-C radiation is effective in deactivating a wide range of microorganisms. The increasing need for effective microbial deactivation methods has led to the exploration of ultraviolet (UV) light-emitting diodes (LEDs) as a possible solution. This study presents the design, construction, and testing of solar-powered UV LED systems that can deactivate different bacteriophages like MS2 and Phi6. The experimental approach involved designing and building the prototype of UV LEDs disinfection system, testing their effectiveness in deactivating microbes using cell culture method and integrating them with solar power. We developed four distinct UV LED systems with wavelengths of 255 nm, 265 nm, 275 nm, and 285 nm, each demonstrating irradiance levels of 393, 404, 44.7, and 582 µW/cm², respectively at the distance where the microbial samples are placed. This research focuses on precise control of UV exposure parameters, including precise adjustments to UV dose, irradiance, and exposure time resulting in substantial microbial reduction. The result for the 275 nm UV LED system shows a 1.16 log reduction of MS2 with a UV dose of 26.82 mJ/cm² and a 1.26 log reduction of Phi6 with a dose of 32.81 mJ/cm². These correspond to 93% and 94.5% reduction of MS2 and Phi6 respectively. These outcomes show the considerable potential of the designed UV-LED system as a targeted and versatile disinfection technology, showing substantial implications for real-world applications. Moreover, the prospect of integrating solar cell technology in future research endeavors holds promise for the development of self-sustained and renewable disinfection systems. Another possible application of this research in computing is the development of smart disinfection systems. By integrating UV LED systems with sensors, Internet of Things (IoT) devices, and artificial intelligence algorithms, disinfection could become more targeted and efficient.
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Abstract Number: ANPA2024-N00091 Presenting Author: Sanjib K C Presenter's Affiliation: Georgia State University Title: Space Radiation in Earth Environment with Radiation Data Portal Location: In-Person Presentation, Fayetteville Show/Hide Abstract Monitoring and analyzing the radiation environment in the Earth's lower atmosphere is essential for safeguarding the well-being of aircraft and spacecraft crews and passengers. Addressing the problem requires a complex approach of integrating different data sources and enhancing the visualization and search capabilities. Additionally, the development of data-driven radiative environment prediction models demands a significant investment in data preparation. This study highlights the expansion of the Radiation Data Portal (RDP) database and the construction of a Machine Learning-ready (ML-ready) dataset for predicting effective dose rates at airplane heights. The RDP allows users to explore recent measurements obtained from the Automated Radiation Measurements for Aerospace Safety (ARMAS) device spanning from 2013 to 2023, along with data describing terrestrial and space environments, including cosmic rays, solar wind, energetic particles, and geomagnetic activity. ARMAS data suitable for ML purposes are semi-manually down-selected and partitioned into three sets while preserving consistent statistical properties. Furthermore, the study utilizes machine learning (ML) approaches to analyze the data and make various predictions, thus enhancing understanding and forecasting capabilities crucial for aviation safety. The results of statistical analysis of radiation measurements are discussed, alongside a comparison with predictions from the Nowcast of the Atmospheric Ionizing Radiation for Aerospace Safety (NAIRAS V3) model.
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Abstract Number: ANPA2024-N00093 Presenting Author: Chandra P. Joshi Presenter's Affiliation: University of North Carolina at Asheville Title: An Approach to Near Hundred Percent Success in the Class Location: In-Person Presentation, Fayetteville Show/Hide Abstract In this presentation, the results of teaching experience of all levels of Physics to major and non major to undergraduate students will be presented. Over the time of research, with an aim of ‘going out of the box’, it was looked into how we can attempt that none of our students (or minimum) fail in the course, obtain the grades more than our students expected on the first day in class, and get the high standard of understanding Physics. We have the experience with the conclusion that the above-mentioned arguments are achievable. In addition to the innovative teaching method, we explored the other aspects of students such as assisting in the student’s health, job or any other issues that bother our students from getting success in the class. We found that in some of the classes as high as 50-70% of our students are ill and 50% of which are with mental health issues. Assisting our students in those issues were more important for their success than just the student’s intellectual capability. We emphasized heavily for the lowest friction between instructor and student so that students shared their hardships freely, they got assured that this instructor is truly working for each of our success. Also, the theme of the course is not to focus only on the grades and passing the course rather focus heavily on the understanding of the contents. By minimizing the fear of tests, which is achieved from the assured success for each of our students, and with the notion that tests are for each of our students’, an opportunity to express themselves and to gauge how much
they know the content covered before the test. Tests are also the time when we learn and
understand best. With this notion, we abolished the concept of completing the test within
stipulated time, rather we made them open ended timing for the tests. Finally, we will present the example of how numerous of our students who were supposed to be weaker or failure in the class according to 'traditional settings', have achieved the success that we would not have expected if this "out of box setting" was not used. In this way, we are able to ensure each of our students’ success. This is not a lenient instructor’s method, rather this instructor has challenged oneself to achieve this tough goal working diligently with the students. This is a noble method, probably rarely employed so far, and developed through systematic research and accumulated experience over several years of time. The advantage of such a method is limitless.
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Abstract Number: ANPA2024-N00094 Presenting Author: Umesh Silwal Presenter's Affiliation: University of North Carolina at Charlotte Title: Evidence-based Teaching Practices in Physics: An Overview on Authentic Teaching and Learning Location: In-Person Presentation, Fayetteville Show/Hide Abstract Learning is inherently a social process as outlined by the theory of constructivism and it requires multiple means of engagement, representation, action, and assessment. Our current challenge in physics teaching is the designing of proper instructional materials and strategies that engage students, facilitate their understanding and retention of concepts, and their generalization in real-world situations. Ultimately, this should promote the learners to take ownership of their learning. This talk will summarize what Physics Education Research (PER) encompasses, the best practices in designing curriculums, and evidence-based instructional strategies for enhancing students' engagement toward learning physics.
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Abstract Number: ANPA2024-N00095 Presenting Author: Nabin Malakar Presenter's Affiliation: Worcester State University Title: Information to Action Using Air Pollution data from Satellites and ground stations Location: In-Person Presentation, Fayetteville Show/Hide Abstract We will present a case study of Nepal, where an effective management of air quality is hindered by a significant lack of comprehensive air pollution data. This deficiency challenges the ability of both governmental and non-governmental organizations to fully grasp the extent and impact of air pollution. As an example, there is a huge disparity between the World Health Organization's standards and Nepal's national air quality standards, clearly underscoring the urgency for more accurate data to inform policy. One needs to leverage both satellite and ground-station data to fill existing data gaps and enhance air quality management strategies. By integrating data from these diverse sources, it can provide a more robust understanding of air quality patterns, which is essential for crafting targeted environmental policies. These policies may include promotion of clean energy sources, stricter industrial emission standards, among others. Furthermore, encouraging the utility of citizen science in gathering localized data and promoting community engagement can help address the critical data gap. This approach not only increases public awareness of air pollution's dangers but also empowers citizens to advocate for and support effective environmental policies. Ultimately, by improving the precision and scope of air pollution data, the data-driven strategy seeks to refine Nepal's air quality management and ensure that policies are responsive to the real-time needs and conditions of its populace, thereby mitigating the adverse health and environmental impacts of air pollution.
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Abstract Number: ANPA2024-N00096 Presenting Author: Bhoj Gautam Presenter's Affiliation: Fayetteville State University Title: Gamma Radiation Induced Structural Changes in Two Dimensional MXenes Location: In-Person Presentation, Fayetteville Show/Hide Abstract High electronic conductivity, structural diversity, and hydrophilicity of two dimensional MXenes opened broad prospects for their applications in variety of industrial and technological areas including energy storage, optoelectronics, spintronics, catalysis, and sensing. In this work, we studied the effect of gamma radiation on surface characteristics of mild etched Ti3C2TX MXene using Raman spectroscopy. Ti3C2TX MXene was synthesized by adding Ti3AlC2 powders into the LiF/HCl solution and was etched for 7 days at 70 °C. There are several spectral features apparent in the Raman Spectra. The peak ~200 cm−1 peak is related to A1g(Ti, O, C) band whereas peak ~ 720 corresponds to cm−1 A1g(C). These two Raman bands are highly diminished with the 1MGy dose of gamma radiation. The 150 cm−1 was enhanced in gamma irradiated sample indicating that gamma radiation activates the oxidation of surface titanium atoms. In addition, the different intensity of D (1350 cm−1) and G ( 1570 cm−1 ) bands between pristine and gamma irradiated MXenes indicates that the extent of amorphous carbon can also be tuned by gamma irradiation.
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Abstract Number: ANPA2024-N00097 Presenting Author: Dr. Nisha H. Makani Presenter's Affiliation: Fayetteville state university Title: Enhancing optical characteristics of Ti3C2 MXene quantum dots through hydrothermal and electrochemical synthesis methods Location: In-Person Presentation, Fayetteville Show/Hide Abstract The remarkable capabilities of Ti3C2 MXene quantum dots (QDs) have showcased their immense potential in various domains such as biological imaging, optical sensing, photoelectric conversion, etc. In this study, Ti3C2 QDs were synthesized via two distinct methodologies: hydrothermal and electrochemical routes. The hydrothermal approach involved the use of LiF and HCl to etch titanium aluminum carbide (Ti3AlC2), followed by controlled heating of the decanted solution to produce the QDs. Conversely, the electrochemical method employed a three-electrode configuration with Ti3AlC2 as the working electrode and an ionic liquid electrolyte to synthesize the QDs directly. Structural characterization was performed using X-ray diffraction (XRD) and Scanning electron microscopy (SEM), confirming the successful etching of aluminum from the Ti3AlC2 phase. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to measure the size of the QDs, which fell within the nanometer range, confirming the formation of QDs. Optical properties were assessed through UV-Vis spectroscopy and fluorescence lifetime measurements, showing distinct absorption and emission profiles for both sets of QDs. The hydrothermally synthesized QDs exhibited UV absorption between 200-220 nm and visible emission from 300-450 nm. Conversely, electrochemically synthesized QDs absorbed violet to blue light 350-400 nm with broader emission 400-500 nm, indicating the potential for various fluorescence imaging applications. This study showcases an expandable strategy for creating high-grade QDs with tunable optical features, catering to the needs of advanced optoelectronic devices.
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Abstract Number: ANPA2024-N00098 Presenting Author: Pravin Sharma Presenter's Affiliation: William & Mary Title: Atomistic Investigation of Ultrafast demagnetization of Permalloy films with varying laser fluence Location: In-Person Presentation, Fayetteville Show/Hide Abstract Permalloy (Ni80Fe20) is one of the soft ferromagnetic materials and promising for applications in spintronic devices with vanishing magnetic anisotropy and a remarkably high permeability with a diminishing coercive field. These properties are used for magnetometers, hard disk drive heads, and all-optical recording devices. For magneto-optic recording devices operating on a nanosecond timescale, the standard demagnetization technique is appropriate, but it is limited by the current speed at which magnetization can be manipulated. Employing ultrafast laser pulses holds immense potential in ferromagnetic permalloy in spin-based memory and storage devices with ultrafast processing speed which include laser-induced opto-magnetism. Here, we employ an atomistic spin dynamics model using a nearest-neighbor Heisenberg Hamiltonian exchange to study computationally the laser-induced magnetization dynamics. We study various timescales, various thicknesses of Permalloy thin films, and with varying laser fluences at different temperature. In addition to the ultrafast dynamics, we have also observed the precession frequency of the magnetization in the Permalloy layer at different temperatures with varying external magnetic fields. The atomistic simulations of the magnetization dynamics and precession frequency give good agreement with the experimental measurements for similar systems. Our work gives insight into the unification of ultrafast magnetic processes and its control over various timescales which can provide a guide to experiments directed to the future development of nanoscale devices in spintronics.
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Abstract Number: ANPA2024-N00099 Presenting Author: Tikaram Neupane Presenter's Affiliation: The University of North Carolina at Pembroke Title: Optical Properties of Cadmium Selenide Quantum Dots Location: In-Person Presentation, Fayetteville Show/Hide Abstract The optical properties of Cadmium Selenide (CdSe) Quantum Dots (QDs) play a pivotal role in modern technology, particularly in fields like optoelectronics, biomedical imaging, and solar cells, owing to their size-dependent tunable optical and electronic characteristics. This study focuses on characterizing optical properties of CdSe QDs including linear absorption, emission spectra, and exciton lifetime for varying sizes of 2.2 nm, 3.8 nm, and 6.5 nm in diameter. As anticipated, the absorption spectra exhibit a shift towards lower energy (or longer wavelength) as the QD size increases. The emission spectra of the QDs demonstrate a blue shift in frequency, with the emission energy lower than the first absorption peak, indicative of a Stokes shift. Specifically, the Stokes shifts were measured to be 17.1 nm, 18.4 nm, and 21.5 nm for QD sizes of 6.5 nm, 3.8 nm, and 2.2 nm, respectively. In addition, time-resolved spectroscopy is utilized to estimate optical bandgap-dependent exciton lifetime to understand the radiative and non-radiative decay process.
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