DEPARTMENT OF PHYSICS

The prospective use of lead(II) sulfide (PbS) perovskite in thermometric, optoelectronics, and photovoltaic have attracted a lot of interest. However, a number of issues, such as inadequate optical absorption, mechanical softness, suboptimal electrical characteristics, and structural instability, make practical use of it difficult. In this work, we thoroughly examine the structural, mechanical, electrical, and optical characteristics of PbS perovskite using first-principles density functional theory (DFT) computations. Our study reveals the fundamental stability requirements by analyzing formation energies and elastic constants. By analyzing the material's mechanical characteristics, including bulk modulus, shear modulus, and Poisson's ratio, the mechanical resilience of the material is evaluated. In order to maximize light-harvesting capabilities, optical characteristics such as the dielectric function and absorption coefficient are also investigated. We suggest doping, strain engineering, and defect passivation techniques to improve PbS's stability, mechanical strength, and optoelectronic efficiency in order to get beyond current restrictions. Our research provides important information for improving PbS-based materials for upcoming electrical and energy applications.

The surface free energy of nanoparticles is important as it gives us vital information about the reactivity and stability of nanoparticles. Starting from a previously reported equation, a theoretical model that involves a specific term for calculating the cohesive energy of nanoparticles, is established in a view to describe the surface free energy of metallic nanoparticles ( using different shapes of particle; sphere, cube and disk). The results show that the behaviour of surface free energy for spherical nanoparticles is the most realistic shape compared to disk and cubic shaped nanoparticles. As the surface free energy differs from shape to shape we also see that its value falls as the number of atoms (nanoparticle size) decreases. The results are in close agreement with the results of Fathi and Ayyad (2014).

Proteins play crucial roles in biological processes, with their functions intricately tied to their three-dimensional structures. Protein folding, the process by which a linear chain of amino acids transforms into its functional conformation, is fundamental to understanding protein function and dysfunction. In this study, we delve into the fascinating world of protein folding, focusing on the hemoglobin molecule as a case study. Hemoglobin, a vital protein responsible for oxygen transport in the blood, undergoes intricate folding processes to achieve its functional form. Through computational simulations, experimental data analysis, and literature review, we explore the mechanisms underlying hemoglobin folding, highlighting key factors influencing its stability and dynamics. Understanding the intricacies of hemoglobin folding not only sheds light on fundamental biological processes but also holds implications for diseases associated with protein misfolding, such as sickle cell anemia and other hemoglobinopathies. This study contributes to the broader understanding of protein folding dynamics and its implications for health and disease

Global statistics estimated that at the end of 2018, there were 9.3 billionmobilephone subscriptions, today virtually everyone has a cell phone. Shouldthesephones constitute a health hazard it would be a global pandemic. Soundispartof our daily life and sounds produced from phones are closest to us. This studywas undertaken to measure the frequency spectra of the sound producedbythree phones commonly used in Nigeria to determine if sound level exposuresfrom these phones should warrant the inclusion of a hearing protectionprogramme. Data was collected and evaluated to ascertain the impact of soundfrom three different types of phones: GSM mobile phone made by Nokia(Nokia1280), an android phone made by Infinix (Infinix Note 8) and an Iphonemadeby Apple (iPhone X), using a UT353 BT Mini Sound Meter (BluetoothVersion). The results showed that the total sound pressure levels for Nokia1280was 109.63dB and average of 98.83dB. This value exceeds the NIOSHallowable noise exposure levels of 85dB thus there is a cause for concerninusing Nokia 1280 to play music for a long time. While the total soundpressurelevels for Infinix Note 8 was 96.79dB which was slightly higher thantheNIOSH allowable noise exposure levels of 95dB for 1 hour but onaverageitwas found to be in line with the allowable noise exposure levels of 85dB. Asimilar lower sound level was observed in the Iphone X, an average of 77.25dBand a total of 88.05dB was recorded within an hour period. This is very safe according to the NIOSH Recommendations which stipulates that onlyover a4-hour period of continues sound can this value become a potential healthrisk. Itwas concluded that phones produced more recently takes into consideration the sound pressure levels and are current design following the NIOSHRecommendations, while older phone may pose a health risk as they hadhighervalues of sound pressure levels. It was therefore recommended that moreresearch need be carried out on the sound level measurement of different phonesas this will inform buyers and producers of these devices on thehealthramifications in using these phones.

A 2-D geoelectrical resistivity survey was carried out on two different locations (hall 2 and hall 3) in University of Benin, Benin City, Edo State, Nigeria, for subsurface lithology. The Wenner array configuration and Pasi Earth resistivity meter was engaged for the acquisition of fields datasets. The data were subjected to an inversion using RES2DINV software for analysis and interpretation. The lateral spacing used was 160m and the total depth for the first and second locations were 136m and 64m respectively. The resistivity of the various surveys ranges from 57Ωm to 1261Ωm for survey line 1 and 1Ωm to 631Ωm for survey line 2. The geological interpretation of survey line 1 reveals the presence of possibly clayey sand and sand having resistivity values of 50Ωm - 500Ωm and 800Ωm - 1200Ωm respectively. Survey line 2 reveals the presence of possibly laterite soil, clay, alluvium soil having resistivity values of 10Ωm - 88Ωm, 50Ωm - 100Ωm, and 200Ωm - 800Ωm respectively. Results for this study shows that buildings can be erected in the survey line 1 which has large deposit of sand. For survey line 2, excavations and sand filling of the area should be done before erecting buildings to prevent building collapse because of the large deposit of clay

Characterizing the shallow subsurface is a crucial requirement for a wide range of applications and disciplines, including those relevant to hydrogeology, agriculture, civil and structural engineering, and in environmental studies (Ehirim, 2010). Geophysical methods offer relatively fast, efficient and cost effective tools for diagnosing the subsurface state to assess their capability to sustain social infrastructures such as high rise buildings, roads and railways, and for environmental monitoring to follow lateral and temporal evolution of plumes in polluted soils, which serve as fundamental basis for successful remediation of such
polluted zones.

Tin (ll) oxide was successfully deposited on glass based at room temperature using an amplified Solution Growth Technique (SGT) at a concentration of 0.12 molarity for different lengths of time (12, 18, 24, 30 and 36hrs). The glass slides went to degreasing by being submerged in concentrated Hydrochloric acid for three days, then it was rinsed in
distilled water and was main goal was air dried. A T80+ UV/VIS Double beam spectrophotometer was made use of to obtain Absorbance spectra (A) within the wavelength spectrum ranging from 202 to 315nm. The optical properties and solid-state characteristics of the films were calculated from the result gotten and mixed against other deposited thin films. The average optical and solid state properties includes: absorbance (A) = 0.658 - 0.551, transmittance (T) = 0.222 - 0.281, Reflectance (R) = 0.564 - 0.730, absorbing power =5.85 x 10 6 - 4.99 x 10 6m-1 , Refractive index (n) = 7.032 - 12.736, Film thickness (t) = -0.073 - (- 0.063) and bandgap (Eg)= 4.754 - 4.693eV. The deposited films within light range (≈4.0- 5.0eV) finds application in Solar Cells for high energy photons: materials with wider bandgap can capture high energy UV photons, potentially increasing the efficiency of solar cells to improve the standard of living in rural areas.

Density functional theory calculations have been carried out on the Structural, Mechanical and Electronic Properties of KMnF3 and SrMoO3 Perovskite Materials based on the Density Functional Theory (DFT) by using the Ultra Soft Pseudo Potential (USPP) from the Quantum Expresso (QE) software program. The generalized gradient approximation of Perdew-Burke-Ernzerhof
(GGA) is used in the calculation of total energy. The lattice constant of both compounds are well optimized. The calculated equilibrium lattice parameters, band structures, elastic constants and the elastic moduli of both KMgF3 and SrMoO3 perovskite compounds are in good agreement with theoretical results. Furthermore, I was able to obtain the Density of State and Band structure graphs for both compounds to determine their electronic properties

Thin films of Strontium iodide (SrI2) were successfully deposited on glass slides at a temperature of 50°C in a chemical bath for 7½ hours, using improved solution growth technique (SGT) in different molar concentrations ranging from 0.03M. 0.06M, 0.09M, 0.12M and 0.15M. A Double beam spectrophotometer was used to obtain the spectra absorbance data while the other properties were calculated using the theory. The average optical and solid state properties include Absorbance (A)=0.149-0.541 Reflectance (R)- 0.141-0.203, Transmittance (T)=0.288-0.710, Absorbing Power (a)=0.342- 1.25, Refractive Index (n)=2.20-2.64. Film Thickness (0=0.937-0.972, and Band Gap (Eg)-3.318-3.419. While the Strontium thin films can be used as antireflection coatings, it is observed that thin films with refractive index greater than 1.9 can be used as Construction of Poultry house, solar cells, etc. The deposited thin films have band gap within light energy range from 1.5-3.0 eV of the electromagnetic spectrum and could be useful for applications in solar electricity for rural electrification which improves the standard of living. telecommunication

I have used the newly formulated Analytical Equivalent Crystal Theory method which is a modification of the AECT method is use to calculate the surface energies and surface relaxation for three low-index surface of Bcc transition metals. Fe,W and Mo. Our calculations predicted top layer contractions for the Bcc metals in reasonable agreement with experiment and theory. The data may be used as a starting point for models of surface science phenomena. The accuracy of the surface energies and relaxation is established from a comparison with other theoretical results and experiments