An Accelerated Homotopy Perturbation Method for Solving Nonlinear Two-Dimensional Volterra-Fredholm Integrodifferential Equations

We propose and apply coupling of the variational iteration method (VIM) and homotopy perturbation method (HPM) to solve nonlinear mixed Volterra-Fredholm integrodifferential equations (VFIDE). In this approach, we use a new formula called variational homotopy perturbation method (VHPM) and variational accelerated homotopy perturbation method (VAHPM). This approach is based on the form of He’s polynomials and on a new form of He’s polynomials. We discuss the convergence of the technique. Some numerical examples are introduced to verify the efficiency of this technique

High-Torque-Density Low-Cost Magnetic Gear Utilizing Hybrid Magnets and Advanced Materials

Two major challenges of existing high-performance magnetic gears are: (i) High content of rare-earth permanent magnets which results in high cost as well as price fluctuation; (ii) Conflict between mechanical and electromagnetic performances, especially in the design of highspeed rotor. A magnetic gear using a blend of magnet types, i.e NdFeB, or Dy-free NdFeB and ferrites, is proposed in this paper. The goal is to bring down the cost while retaining comparable torque-transducing performance to a baseline magnetic gear only using rare-earth NdFeB magnets. A variety of topologies based on different combinations of magnet types and geometric shapes have been studied and compared. In addition, the potential impact of using an advanced dual-phase material is evaluated. The goal is to eliminate the well-known tradeoff between rotor mechanical integrity and PM flux leakage

Investigating the removal of some pharmaceutical compounds in hospital wastewater treatment plants operating in Saudi Arabia

The concentrations of 12 pharmaceutical compounds (atenolol, erythromycin, cyclophosphamide, paracetamol, bezafibrate, carbamazepine, ciprofloxacin, caffeine, clarithromycin, lidocaine, sulfamethoxazole and Nacetylsulfamethoxazol (NACS)) were investigated in the influents and effluents of two hospital wastewater treatment plants (HWWTPs) in Saudi Arabia. The majority of the target analytes were detected in the influent samples apart from bezafibrate, cyclophosphamide, and erythromycin. Caffeine and paracetamol were detected in the influent at particularly high concentrations up to 75 and 12 ug/L, respectively. High removal efficiencies of the pharmaceutical compounds were observed in both HWWTPs, with greater than 90 % removal on average. Paracetamol, sulfamethoxazole, NACS, ciprofloxacin, and caffeine were eliminated by between >95 and >99 % on average. Atenolol, carbamazepine, and clarithromycin were eliminated by >86 % on average. Of particular interest were the high removal efficiencies of carbamazepine and antibiotics that were achieved by the HWWTPs; these compounds have been reported to be relatively recalcitrant to biological treatment and are generally only partially removed. Elevated temperatures and high levels of sunlight were considered to be the main factors that enhanced the removal of these compounds

Neonatal Outcomes in Type 1 Diabetes Pregnant Women, A Single-Center Retrospective Study

Background: Pregnancy in women with type 1 diabetes mellitus (T1DM) is associated with an increased risk of congenital malformations, and obstetric complications including increased rates of cesarean section birth, prematurity, and neonatal adverse outcomes including large for gestational age (LAG), and hypoglycemia. Our aim of this study is to investigate and evaluate the prevalence and the different neonatal outcomes of T1DM pregnant women compared to nondiabetic healthy pregnant women in a single-center experience to improve the effectiveness of interventions for the treatment of pregnant women with T1DM. Methods: This is a retrospective cohort study of 113 pregnant women (43 pregnant patients with T1DM and 70 non-diabetic healthy pregnant women) who underwent regular follow-in the antenatal period and delivered at King Fahad Military Medical Complex (KMMC) - Dhahran between 2018 and 2023. Results: A total of 117 pregnant women (47 with Type-1 diabetes mellitus-T1DM and 70 healthy controls) were included in the study. The proportion of elective C-sections was significantly high in women with T1DM 21 (44.7%) and the proportion of neonatal hypoglycemia who need treatment was also significantly high in diabetic women 20 (42.6%). NICU/SCBU admission was significantly high in diabetic women 23 (48.9%). Conclusion: The high prevalence of neonatal adverse outcomes especially hypoglycemia and intensive care admission of T1DM pregnant women compared to non-diabetic pregnant women indicates that this model of antenatal diabetes care must be improved to enhance maternal and fetal outcomes, especially in such high-risk groups and challenging problems

Epidemiology of Autoimmune Diseases among Attendants of General Hospitals in Aseer region

It has long been recognized that environmental influences play an important role in the risk of developing Autoimmune disease. Defining specific pathogenic environmental mediators that may trigger the development or progression of autoimmune disease remains a focus of increasing investigative effort. Factors promoting disease may not be identical to factors that influence the severity or progression of the disorder. The cause(s) of autoimmune disorders remain largely unknown. Considerable evidence supports a role for environmental agents in inducing autoimmune disorders. OBJECTIVES: The study aims to explore the risk factors of autoimmune diseases among attendants of general hospitals in Aseer Region. Methods: case control study design was carried out  included 70  patients with multiple types of auto immune diseases attending general hospitals and primary health care centers in Abha city. They were clinically diagnosed as having autoimmune diseases. and 140 clinically free subjects , age and sex matched were included as controls. RESULTS: The present study included 70 autoimmune disease patients predominantly females (88.4%). Their mean age was 42.7 ± 12.1 years and disease duration was 11.2 ± 7.2 years. The mean age of the control group was 47.1 ± 13.6 years with no significant differences in the demographic data between the patients and control (p > 0.05). This study found no significant differences between cases with autoimmune diseases and sociodemographic characteristics. Conclusion :There is multiple determinants and risk factors affecting the occurrence of autoimmune diseases. Familial history, psychological stresses, hormonal supplementation, using hair dyes, smoking and recent vaccination were significant factors associated with autoimmune diseases. Keywords: Epidemiology, autoimmune, diseases, Aseer regio

Estimating the minimum number of SARS-CoV-2 infected cases needed to detect viral RNA in wastewater: To what extent of the outbreak can surveillance of wastewater tell us?

There is increasing interest in wastewater-based epidemiology (WBE) of SARS-CoV-2 RNA to serve as an early warning system for a community. Despite successful detection of SARS-CoV-2 RNA in wastewaters sampled from multiple locations, there is still no clear idea on the minimal number of cases in a community that are associated with a positive detection of the virus in wastewater. To address this knowledge gap, we sampled wastewaters from a septic tank (n = 57) and biological activated sludge tank (n = 52) located on-site of a hospital. The hospital is providing treatment for SARS-CoV-2 infected patients, with the number of hospitalized patients per day known. It was observed that depending on which nucleocapsid gene is targeted by means of RT-qPCR, a range of 253-409 positive cases out of 10,000 persons are required prior to detecting RNA SARS-CoV-2 in wastewater. There was a weak correlation between N1 and N2 gene abundances in wastewater with the number of hospitalized cases. This correlation was however not observed for N3 gene. The frequency of detecting N1 and N2 gene in wastewater was also higher than that for N3 gene. Furthermore, nucleocapsid genes of SARS-CoV-2 were detected at lower frequency in the partially treated wastewater than in the septic tank. In particular, N1 gene abundance was associated with water quality parameters such as total organic carbon and pH. In instances of positive detection, the average abundance of N1 and N3 genes in the activated sludge tank were reduced by 50 and 70% of the levels detected in septic tank, suggesting degradation of the SARS-CoV-2 gene fragments already occurring in the early stages of the wastewater treatment process

The origin of fracture in the I-ECAP of AZ31B magnesium alloy

Magnesium alloys are very promising materials for weight-saving structural applications due to their low density, comparing to other metals and alloys currently used. However, they usually suffer from a limited formability at room temperature and low strength. In order to overcome those issues, processes of severe plastic deformation (SPD) can be utilized to improve mechanical properties, but processing parameters need to be selected with care to avoid fracture, very often observed for those alloys during forming. In the current work, the AZ31B magnesium alloy was subjected to SPD by incremental equal-channel angular pressing (I-ECAP) at temperatures varying from 398 K to 525 K (125 °C to 250 °C) to determine the window of allowable processing parameters. The effects of initial grain size and billet rotation scheme on the occurrence of fracture during I-ECAP were investigated. The initial grain size ranged from 1.5 to 40 µm and the I-ECAP routes tested were A, BC, and C. Microstructures of the processed billets were characterized before and after I-ECAP. It was found that a fine-grained and homogenous microstructure was required to avoid fracture at low temperatures. Strain localization arising from a stress relaxation within recrystallized regions, namely twins and fine-grained zones, was shown to be responsible for the generation of microcracks. Based on the I-ECAP experiments and available literature data for ECAP, a power law between the initial grain size and processing conditions, described by a Zener–Hollomon parameter, has been proposed. Finally, processing by various routes at 473 K (200 °C) revealed that route A was less prone to fracture than routes BC and C