Optimizing the geometry of a cylindrical dielectric resonator antenna (CDRA) in combination with the design of a microstrip patch antenna to improve antenna efficiency.

The primary objective of this study is to improve the efficiency of dielectric resonator antennas (DRAs) by the manipulation of their geometric and material characteristics. Two distinct cylindrical dielectric resonator antenna (DRA) with microstrip patch antenna designs chosen, and deliberate modifications implemented in a systematic manner to enhance crucial characteristics including gain, bandwidth, S-parameters, voltage standing wave ratio (VSWR), and directivity. Furthermore, an investigation conducted to assess the efficacy of incorporating additional layers into the design of the DRA in order to achieve increased gain and enhanced efficiency at a frequency of 28 GHz. The research encompassed the process of collecting and designing and simulating CDRA and microstrip patch antenna antennas utilizing the CST framework. The study investigates different configurations of apertures and alterations or holes in the patch geometry in order to improve both the gain and efficiency. A comparative analysis between both antennas carried out utilizing performance criteria such as S-parameters, gain, directivity, bandwidth, and VSWR and efficiency. The discourse explores the progress made in the field of technology pertaining to the improvement of gain and bandwidth. This includes the utilization of high-dielectric-constant materials, modifications in resonant frequencies, and the implementation of metamaterial (MTM) cells. The CST program utilized for conducting realistic trials and assessments. The research highlights the advantages of CDRA antennas and microstrip patch antennas, including improved radiation efficiency, smaller size, lower profile, and lightweight design. The integration of photonic crystal layers into the design of the cylindrical dielectric resonator antenna (CDRA) emphasized as a noteworthy enhancement, resulting in amplified gain. The significance of taking into account both intrinsic characteristics and external factors, such as surface Plasmon waves, in the computational modeling of DRA antennas to achieve maximum efficiency is emphasized by the research

Estimation of stresses on 155mm artillery projectiles during launch phase using numerical simulations

The paper provides an overview of research (analytical, numerical and experimental methods) related to the stress state of artillery projectiles during movement through the barrel of the weapon. The characteristics of the 155mm HERA M549 and 155mm HE M795 projectiles, used in numerical simulations, are described. As a main goal of the research, numerical simulations were performed with the 155mm projectiles to determine the maximum equivalent stresses that occur during the launch of this ammunition. The obtained values were compared with the yield limit of the materials of the projectile components, in order to assess whether the plastic deformation would occur during the launch phase

Research of influence of different shaped charge liner materials on penetration depth using numerical simulations

Numerical simulations, using the Ansys AUTODYN program, of Panzerfaust 30 (klein) anti-tank warhead were performed to determine the influence of different liner materials on the penetration depth into a steel target. It has been shown that the choice of liner material can significantly affect the performance of the ammunition. Along with other methods of optimizing shaped charge ammunition (ie. optimization of the shape, thickness and angle of the tip of the liner, use of more potent explosive and deviator, optimization of casing thickness and stand-off distance, etc.), the use of appropriate liner material is certainly one of the most important parameters of shaped charge warheads to consider. Together with analytical calculations and experimental tests, simulations are valuable tool. Using data obtained from numerical simulations, researchers can save both time and resources during the process of munition design and optimization

Study of chemical and physical parameters affected on purification of water from inorganic contaminants

The ability to remove perchlorate anions was investigated by the adsorption technique in a laboratory scale and by a batch type unit from contaminated aqueous solutions prepared at specific concentrations. The adsorption process was carried out using banana peels, which were chosen as an available, cheap, and low-cost adsorption media. The studied operating conditions in the treatment process were the acidic function, shaking speed, contact time, temperature, in addition to the initial concentration of perchlorate, which ranging from 1-10, 100-400 rpm, 10-180 min, 20-50 ºC, 50-1000 ppb respectively, while the dose of adsorbent media ranged between 0.5-6 g and the particle size ranged from 0-Pan. The experimental results showed that the removal efficiency of perchlorate changes directly with the shaking speed, contact time, particle size and the dose of adsorbent, while it was inversely with the remaining variables for certain levels. Thus, two types of contaminants were disposed of simultaneously in a beneficial, and eco- friendly manner, reaching to Zero Residue Level (ZRL)

Dynamic response of reinforced concrete beams subjected to low velocity impact loads using nonlinear finite element analysis

The development of a nonlinear finite element method (FEM) for examining how reinforced concrete (RC) beams react to dynamic forces under the action of low-velocity impacting loads is presented in this article. The model was employed to analyze the stress distributions along with the time histories of impacting load and beam deflection, which were presented graphically. Comparisons with experimental data from previously conducted studies have been performed to verify the precision of the studied model. The findings demonstrated that the developed model was acceptable. Furthermore, the study performed a detailed parametric analysis, focusing on various factors such as replacing conventional steel bars with FRP bars, increasing concrete compressive strength, changing the impact location, using different diameters of reinforcing bars, and changing the depth of the concrete beam. According to the findings, using FRP bars resulted in 36% less peak load due to the uplift pressure caused by the FRP bars' high strength, while the maximum observed deflection of the beam reinforced with FRP bars decreased by approximately 9%. When the position of the impacting force was applied at one-third of the span of the beam, deflection was decreased by 12% when compared to the RC beam has been impacted at its midspan. In addition, the depth of the beams had a significant impact on the impacting load. These presented findings of the study may contribute to a better understanding of how a structure made of concrete responds to impacting loading

Analysis of the thermal sensation in single-family home from microclimatic monitoring: Case study Bucaramanga Colombia

The present work describes the experimentation of monitoring for the finding of the heat index and the individual thermal sensation, where the behavior of the real temperature in the exterior and interior of a conventional single-family house with a warm and temperate climate in Colombia was analyzed. The detailed monitoring campaign is carried out for 2880 hours, where the conditions of the interior area of the house and the local climatic conditions of the area are recorded, through the implementation of a thermohydrometers registration system. The methodology for the calculation of the sensation of heat and thermal comfort was determined under the adjusted equation of cooling power of Leonardo Hill and Morikofer-Davos, applied in the analyses of the Institute of Hydrology, Meteorology and Environmental Studies - IDEAM. The results showed a thermal sensation of dissatisfaction of 97.7%, because with the monitored temperature the thermal sensation is calculated yielding in 1382.4 hours with very hot, 1151.6 hours of hot and 280.8 hours of warm thermal sensation

Long-term effect of economic status on auditors' professional skepticism

The goal of the current study was to look into how financial stability affected auditors' professional skepticism. One of the elements that reflects the level of an auditor's professional skepticism in the auditor's choices is prior job experience. Regarding this, 759 businesses registered on the Iraq Stock Exchange were chosen between 2011 and 2021 using the systematic elimination approach. Due to the 2D structure of the logistic dependent variable, the research's regression model was put to the test. The outcome of the research hypothesis test revealed that the auditor's decision-making and judgment were significantly impacted by the economic climate at the start of their assignment. Additionally, it was discovered that businesses that have their financial reports audited by auditors during a recession are less inclined to do so. Our study supported prior research on a range of demographics, including economists, scientists, attorneys, investment bankers, and corporate executives, by demonstrating that the early career stage is a crucial era for auditors' formative development. Our findings may have wide-ranging repercussions for the auditing industry. Our findings imply that there may be a dearth of skeptic auditors in a region following extended periods of economic expansion. Our research serves as a first step in the direction of a deeper comprehension of the formation and recruitment of auditors in the labor market

Identifying the determinants of tax following intention with emphasis on the theory of planned behavior

This research aims to identify the determinants of tax compliance intention, focusing on the theory of planned behavior. This research is practical in its objective and causal in its method. The data collection method was a questionnaire survey with confirmed validity and reliability. The statistical population of this research includes all managers and owners of small and medium enterprises in Iraq, and because the company is unlimited, a sample of 384 companies was studied. The research results show that attitude, perceived behavioral control, and patriotism towards tax compliance are significantly positively related to the intention to facilitate the payment of sales tax among small and medium enterprises

Based BIM techniques to clash detection for construction projects

Building Information Modeling (BIM) has brought about a qualitative change in the design and management of construction projects because it represents a digital simulation of the physical characteristics of the building, and this increases its efficiency before the actual construction begins. In Iraq, most construction projects still use CAD two-dimensional drawing for the purpose of the implementation process, especially government projects, and this causes many problems due to the difficulty of communication between the various disciplines involved in the design and misunderstanding during implementation. This type of problem is reduced by combining BIM drawings prepared by designers and making them into a single model. In this process of merging conflicts are found using BIM tools such as Autodesk Navisworks. There are three main types of detections. This article includes how a clash detector can help improve clashes in the design phase before starting to construct a specific building using BIM applications and focuses on hard detection type (overlap of a particular element with else). The methodology involved in this research is to study an educational building (24-classroom model school) consisting of structural and architectural BIM models only, clash detection analysis is done using Autodesk Revit and Autodesk Navisworks Manage software

A comparative study between shrinkage methods (ridge-lasso) using simulation

The general linear model is widely used in many scientific fields, especially biological ones. The Ordinary Least Squares (OLS) estimators for the coefficients of the general linear model are characterized by good specifications symbolized by the acronym BLUE (Best Linear Unbiased Estimator), provided that the basic assumptions for building the model under study are met. The failure to achieve one of the basic assumptions or hypotheses required to build the model can lead to the emergence of estimators with low bias and high variance, which results in poor performance in both prediction and explanation of the model in question. The hypothesis that there are no multiple linear relationships between the explanatory variables is considered one of the leading hypotheses on which the model is based. Thus, the emergence of this problem leads to misleading results and high (Wide) confidence limits for the estimators associated with those variables due to problems characterizing the model. Shrinkage methods are considered one of the most effective and preferable ways to eliminate the multicollinearity problem. These methods are based on addressing the multicollinearity problems by reducing the variance of estimators in the model. Ridge and Lasso methods represent the most and most common of these methods of shrinkage. The simulation was carried out for different sample sizes (40, 120, 200) and some variables (P=30, 60) in the first and second experiments arbitrarily and at the level of low, medium, and high correlation coefficients (0.2, 0.5, 0.8). When (p=30, 60) Lasso method has the smallest (MSE) than the Ridge method. The Lasso method proved its efficiency by obtaining the least MSE. Optimal Penalty parameter (λ) chosen from Cross-Validation through minimizing (MSE) of prediction. We see a rapid increase for (MSE) for both (Ridge-Lasso) where the top axis indicates the number of model variables, and when the correlation between variables increases and sample size too, we can see the (MSE) values increase in the Ridge method than the Lasso method. A ridge method gives greater efficiency when the sample size is more significant than variables (