University of Wah Journal of Science and Technology (UWJST)

Effect of Structural Modifications on the Electronic Characteristics of Cadmium Oxide

Sumbal Tahir — 2023-12-28

The density function theoretical approach has been utilized for investigating the effect of oxygen deficiency on the electronic and optical characteristics of CdO. For this purpose, Graphical User Inter-phase (GUI) of Quantum Espresso i.e. BURAI 1.3 is used first to estimate the lattice parameters of CdO that are in total agreement with earlier experimental and/or theoretical findings i.e calculations show that SCF converges with total energy value of -586.6300 After creating a CdO super cell initially with a [2x1x1] scale, the changed properties of CdO were then evaluated at the supercell level to determine the impact of oxygen deficit on the electronic features of CdO. The results reveal that creating oxygen vacancy at supercellular level significantly affects the electronic characteristics of CdO as the conduction and valance band gap has lesser value after modification in the CdO structure. Furtherance to it, the depicted picture of band structure and state densities confirmed the semi-conducting characteristics of CdO because of presence of direct band gap at 1.30 eV after O-vacancy. Due to the aforementioned structural changes, an increase in conductivity and electron movement is expected. However, it is determined that the lattice constants' findings are reliable, and the behavior of CdO remains nonmagnetic and semiconducting on inducing oxygen vacancies.

An improved regression type mean estimator using redescending M-estimator

Mubeen Mukhtar — 2023-12-28

In this article, a novel technique is presented for calculating the mean of a countable population using simple random sampling (SRS) in situations where there are outliers in the data. The proposed approach employs a robust regression type estimation method called re-descending M-estimation. To assess the effectiveness of the new method, the mean square error (MSE) equation is derived using a first-order approximation and compared against existing estimation methods. Furthermore, the percentage relative efficiency (PRE) of the proposed estimator is calculated in comparison to other estimators. Real-life data sets are employed to demonstrate the efficacy of the suggested approach. The results indicate that the proposed estimator outperforms other estimators in the literature.

Catalogue of Efficient Repeated Measurements Designs for p3 = 5, 6, 7

Muhammad Riaz — 2023-12-28

Minimal strongly balanced repeated measurements designs are economical to (i) balance the residual effects, and (ii) estimate the treatment effects and residual effects independently. The situations where these minimal designs cannot be constructed, minimal nearly strongly balanced repeated measurements designs are used. In this article, some efficient minimal circular nearly strongly balanced repeated measurements designs are constructed in periods of three different sizes with the smallest of sizes 5, 6, and 7.

A New K-Product Generalized Transformation: Investigating Weibull Distribution as the Baseline

Zawar Hussain — 2023-12-28

This article is about defining and studying an improved technique of parameter induction to a continuous probability distribution through a new G-class of probability models. In particular, the Weibull distribution is used in the defined technique and it is named as KP-W distribution. The importance of this generalization of Weibull distribution comes from its ability to model various kinds of hazard functions such as ascending, descending, first decreasing and then increasing, or constant hazard rate functions. Different properties of this generalized modified model have been deliberated along with raw moments and functions which can generate moments, quantiles, hazard function, Rényi entropy, stress-strength parameter, order statistics, the average time to wait until served and average remaining life. Maximum likelihood (ML) estimation of the proposed G class and its sub-model, the KP-W is also presented. Finally, the KP-W model is judged for its goodness to fit using data sets from different fields to showcase its practical applications.

New analytical wave structures for some nonlinear dynamical models via mathematical technique

Jamshad Ahmad — 2023-12-28

In this paper, we used Yu-Toda-Sasa-Fukuyama (YTSF) model, the (2 + 1)-dimensional nonlinear evolution equation, and water wave propagation with surface tension to find new traveling wave solutions by applying exp(??(?))expansion method (EEM). The proposed nonlinear wave models are essential in coastal and offshore studies to understand wave propagation, wave transformation, and coastal processes. They also play a crucial role in cryptography, the regulation of heartbeats, and mathematical physics. We generate 3D, 2D, and contour plots of discovered solutions by selecting suitable values for arbitrary parameters within the accurate range space. Hyperbolic, trigonometric, and exponential functions are used to express the resulting traveling wave solutions. The received solutions included dark, bright, periodic, kink, singular, bell-type, hyperbolic solitary wave solutions, and many more. By changing model parameters, it is possible to change the dynamics of the solutions that the model generates. These results highlight the complexity and nonlinear behavior of the system, indicating the need for further analysis and providing valuable insights for understanding and modeling similar physical systems. This work breaks new ground by utilizing the EEM to uncover solitonic solutions for an unsolved model, pushing the boundaries of the existing literature by introducing a new mathematical technique for addressing fractional nonlinear physical models. The proposed method is brief, clear, and trustworthy, resulting in fewer calculations and broad application.

Optimization of Methanol and Sodium Hydroxide used in the Production of Biodiesel using Jatropha Oil

Ejaz Mahmood Shahid Chaudhry — 2023-12-28

The popularity of biofuel is increasing rapidly due to scarcity of petroleum fuel and its equitableness towards the environment issues. Mostly biodiesel is produced with transesterification, in which organic oils or analogous stuff is reacted with alcohol in the presence of a suitable catalyst.In this study Methanol and Sodium Hydroxide (NaOH), as catalyst, was used to transesterify the Jatropha Oil. Since the economic sustainability is very important, so the study was made to cut down the cost of production of biodiesel. As the cost of Methanol and NaOH is considerable, so the amount of methanol and Sodium Hydroxide was optimized. The amount of methanol varied from 10% to 30% and NaOH varied from 8% to 20%. It was found that 21% methanol and 10.5% NaOH (m/v) revealed the highest yield i.e.96%, when Jatropha oil was used as feedstock. Mathematical model was developed and theoretical results were compared with experimental results. Both models were superimposed and a comprehensive correlation was established.