Elastic-plastic analysis of pressure vessels and rotating disks made of functionally graded materials using the isogeometric approach

An NURBS-based isogeometric analysis for elastic-plastic stress in a cylindrical pressure vessel is presented. The vessel is made of a ceramic/metal functionally graded material, i.e. a particle-reinforced composite. It is assumed that the material plastic deformation follows an isotropic strain-hardening rule based on the von Mises yield criterion. The mechanical properties of the graded material are modelled by the modified rule of mixtures. Selected finite element results are also presented to establish the supporting evidence for validation of the isogeometric analysis. Similar analyses are performed and solutions for spherical pressure vessel and rotating disk made of FGMs are also provided

The Effect of Fungal Decay on Ficus Sycomorus Wood

The deterioration of wood on account of microbiological agents is an acknowledged fact. Botryodiplodia theobromae - Trichoderma longibrachiatum - Aspergillus candidus - Aspergillus ustus and Aspergillus terreus were isolated from two wooden masks dating back to the Greek- Roman period in Egypt. The chemical composition of wood is easily affected after any attack and visible changes can be noticed clearly after some time, but the degree of deterioration of wood constituents cannot be estimated unless the wood is closely studied. Ficus sycomorus wood samples, which had been infected by the fungi isolated from the masks, were studied by using X Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy with Attenuation Total Reflection (FTIR-ATR)

Plasma Adrenomedullin level in Egyptian children and Adolescents with type 1 diabetes mellitus: relationship to microvascular complications

<p>Abstract</p> <p>Background</p> <p>Adrenomedullin (AM) is known to be elevated in different clinical situations including diabetes mellitus (DM), but its potential role in the pathogenesis of vascular complications in diabetic children and adolescents is to be clarified. Hence, the study aimed at assessment of plasma adrenomedullin levels in children and adolescents with type 1 DM and correlation of these levels with metabolic control and diabetic microvascular complications (MVC).</p> <p>Methods</p> <p>The study was performed in the Diabetes Specialized Clinic, Children's Hospital of Ain Shams University in Cairo, Egypt. It included 55 diabetic children and adolescents (mean age 13.93 ± 3.15 years) who were subdivided into 40 with no MVC and 15 with MVC. Thirty healthy subjects, age-and sex- matched were included as control group (mean age 12.83 ± 2.82 years). Patients and controls were assessed for glycosylated hemoglobin (HbA1c) and plasma adrenomedullin assay using ELISA technique.</p> <p>Results</p> <p>Mean plasma AM levels were significantly increased in patients with and without MVC compared to control group, (110.6 pg/mL, 60.25 pg/mL and 39.2 pg/mL respectively) (P < 0.01) with higher levels in those with MVC (P < 0.05). Plasma AM levels were positively correlated with both duration of diabetes (ρ = 0.703, P < 0.001) and glycemic control (HbA1c) (ρ = 0.453, P < 0.001).</p> <p>Conclusion</p> <p>Higher plasma AM levels in diabetics particularly in those with MVC & its correlation with diabetes duration and metabolic control may reflect the role of AM in diabetic vasculopathy in the pediatric age group.</p

Decomposition of 1,1-Dichloroethane and 1,1-Dichloroethene in an electron beam generated plasma reactor

An electron beam generated plasma reactor is used to decompose low concentrations (100–3000 ppm) of 1,1-dichloroethane and 1,1-dichloroethene in atmospheric pressure air streams. The energy requirements for 90% and 99% decomposition of each compound are reported as a function of inlet concentration. Dichloroethene decomposition is enhanced by a chlorine radical propagated chain reaction. The chain length of the dichloroethene reaction is estimated to increase with dichloroethene concentration from 10 at 100 ppm initial dichloroethene concentration to 30 at 3000 ppm. Both the dichloroethane and dichloroethene reactions seem to be inhibited by electron scavenging decomposition products. A simple analytic expression is proposed for fitting decomposition data where inhibition effects are important and simple first order kinetics are not observed

Salmonella Infections among Pediatric Population in Qatar: Phenotypic Resistance and Associated Genotypic Determinants

Salmonella is a significant public health burden worldwide and being the most common bacterial diarrheal illness among infants and young children. In the last few years, Qatar reports a high incidence of salmonellosis outbreaks coupled with a significant increase of Multidrug-Resistant (MDR) among pediatric populations every year. This study aims to elucidate the molecular mechanisms underlying resistance to ceftriaxone, cefepime, amoxicillinclavulanate tetracycline, trimethoprim-sulfamethoxazole, chloramphenicol, and azithromycin among Salmonella isolated from the pediatric population. A total of 246 Salmonella isolates were collected from children under 18 years old admitted to the Pediatric Emergency Center (PEC), Hamad Medical Corporation (HMC) from Jan. 2018 to Dec 2019 with gastroenteritis. Isolates were tested for antibiotic susceptibility against nineteen relevant antibiotics using E-test. Resistance was confirmed using PCR-specific primers for 38 genes. Resistance was detected against 14 antibiotics, and 38.2% of isolates were resistant to at least one antibiotic. Overall, we reported 23.9%, resistance to tetracycline 21.1%, ampicillin 18.7%, AMC, and 13% sulfamethoxazole-trimethoprim. Further, 16.2% of the isolates were Multidrug-Resistant (MDR), with 4.1% being Extended-Spectrum β Lactamase (ESBL) producers. 90% of ESBL producers harbored one of bla CTX-M-Group. Class 1 AMC resistant samples showed the highest resistance to different antibiotics. Our results indicate a high antimicrobial resistance pattern of Salmonella and the presence of Class (1) cassette that involves the transmission and expression of the resistance among AMC resistance isolates, which might lead to increased multi-drug resistance. This study provides evidence guidance to activate and implement the pillars of an antimicrobiThis work was supported by Qatar University collaborative grant no.: QUCG-BRC-19/20

Extraction Optimization, Functional and Thermal Properties of Protein from Cherimoya Seed as an Unexploited By-Product

Plant-based proteins are gaining in attraction compared with animal-based proteins due to their superior ethical profiles, growing concerns on the part of various organizations about animal health and welfare, and increased global greenhouse-gas emissions in meat production. In this study, the response surface methodology (RSM) using a Box-Behnken design (BBD) was applied to optimize the ultrasound-assisted alkaline extraction of cherimoya-seed proteins as valuable by-products. The effects of three pH, temperature, and time factors on the protein-extraction yield and protein content were investigated. The pH at 10.5 and temperature of 41.8 °C for 26.1 min were considered the optimal ultrasound-assisted alkaline-extraction conditions since they provided the maximum extraction yield (17.3%) and protein content (65.6%). An established extraction technique was employed to enhance the cherimoya-seed protein yield, purity, and functional properties. A thermogravimetric analysis (TGA) of the samples showed that the ultrasound-assisted alkaline extraction improved the thermal stability of the protein concentrate

Analytical, experimental and numerical study of a graded honeycomb structure under in-plane impact load with low velocity

Given the significance of energy absorption in various industries, light shock absorbers such as honeycomb structure under in-plane and out-of-plane loads have been in the core of attention. The purpose of this research is the analyses of graded honeycomb structure (GHS) behaviour under in-plane impact loading and its optimisation. Primarily, analytical equations for plateau stress and specific energy are represented, taking power hardening model (PHM) and elastic–perfectly plastic model (EPPM) into consideration. For the validation and comparison of acquired analytical equations, the energy absorption of a GHS made of five different aluminium grades is simulated in ABAQUS/CAE. In order to validate the numerical simulation method in ABAQUS, an experimental test has been conducted as the falling a weight with low velocity on a GHS. Numerical results retain an acceptable accordance with experimental ones with a 5.4% occurred error of reaction force. For a structure with a specific kinetic energy, the stress–strain diagram is achieved and compared with the analytical equations obtained. The maximum difference between the numerical and analytical plateau stresses for PHM is 10.58%. However, this value has been measured to be 38.78% for EPPM. In addition, the numerical value of absorbed energy is compared to that of analytical method for two material models. The maximum difference between the numerical and analytical absorbed energies for PHM model is 6.4%, while it retains the value of 48.08% for EPPM. Based on the conducted comparisons, the numerical and analytical results based on PHM are more congruent than EPPM results. Applying sequential quadratic programming method and genetic algorithm, the ratio of structure mass to the absorbed energy is minimised. According to the optimisation results, the structure capacity of absorbing energy increases by 18% compared to the primary model