Dynamic Localizations in Structural Steel at High Strain Rates and Temperatures – COMPLAS XI

The proposed paper presents a numerical study on the formation of shear bands at localized regions in two ferrite steel alloys, HSLA-65 and DH-36, subjected to certain range of velocity impact. Constitutive relations developed by the author [1] for ferritic steels is utilized in simulating the thermal and athermal parts of the flow stress over a wide range of temperatures and strain rates. The proposed plasticity model is implemented into the commercially well-known finite element software ABAQUS through VUMAT user subroutine. This implementation enables studying the shear band formation over a wide range of initial temperatures and strain rates in a cylindrical hat-shaped specimen with certain dimensions where the location of shear localization preceding shear band formation is forced to be between the hat and the brim. Sensitivity analysis is performed on different mesh configurations in order to select the optimum mesh. Another sensitivity analysis is also performed on the constitutive plasticity model material parameters to study their effect on the shear bands formation. Several conclusions related to the width of the shear bands considering the velocity load and initial temperatures will be discussed throughout this work

Generalized β\beta-conformal change and special Finsler spaces

In this paper, we investigate the change of Finslr metrics $$L(x,y) \to\bar{L}(x,y) = f(e^{\sigma(x)}L(x,y),\beta(x,y)),$$ which we refer to as a generalized $\beta$-conformal change. Under this change, we study some special Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible, $C_2$-like, $S_3$-like and $S_4$-like Finsler spaces. We also obtain the transformation of the T-tensor under this change and study some interesting special cases. We then impose a certain condition on the generalized $\beta$-conformal change, which we call the b-condition, and investigate the geometric consequences of such condition. Finally, we give the conditions under which a generalized $\beta$-conformal change is projective and generalize some known results in the literature.Comment: References added, some modifications are performed, LateX file, 24 page

“Experimental and Theoretical Study of a Multi- Stage Solar Still Connected to Evacuated Solar Collector Tubes”

التقطير الشمسي أحد الحلول الفعالة والمفيدة لحل مشكلة شحة المياه النقية على سطح الارض. استعمل مقطر شمسي متعدد الطبقات وتم تحسين ادائه من خلال ربطه بانابيب مفرغة لتجميع الطاقة الشمسية. فكانت نسبة الزيادة بالانتاجية عن الانواع الاخرى بنسبة (38%). اجريت دراستان عملية ونظرية لحالتان الاولى كانت باحتواء خزانات المقطر الشمسي على الماء فقط من دون اي اضافة اما الحالة الاخرى فكانت باضافة ليف النخل الى حوض المرحلة الاولى. اضافة ليف النخل حسن من الانناجية الليلية للمقطر فكانت نسبة الزيادة في الانتاجية الليلية حوالي (25%) عما هو فارغ. يعتبر هذا النوع من المقطرات الشمسية تقنية حديثة في تحسين اداء المقطرات الشمسية متعددة الطبقات.Solar distillation is an effective and a useful method to solve the problem of water scarcity usable on the surface of the earth. A multi-stage solar still was used, and the performance of it was improved by linking it to (Evacuated Solar Collector Tubes), the rate of increase in productivity is about (38%). Practical and theoretical calculations were carried out on two cases. The first case was the basin of the first stage containing water only; the second case was the basin containing the fiber of the palm. When comparing the two cases there was a similarity between the two cases, but the addition of leaf fiber improved the increase in night productivity. The rate of increase in night productivity is about (25%).This type of solar still was a modern technology in improving the performance of multi-stage solar still

Effect of Vitamin D3 Supplement on the Semen Quality in Human Patients with Vitamin D Deficiency

Thermophilic bacteria are a source of bioactive compounds that have many benefits for human life. One of them is as a source of antimicrobials. This research aimed to identify and characterize the promising thermophilic bacterial isolates by analyzing bioactive compounds and their potential as antimicrobial agents. Thermophilic bacteria with the code LBKURCC were taken from the collection of the Biochemistry Laboratory of the University of Riau. Forty-four purified strains of thermophilic bacteria were tested for antimicrobial ability. These thermophilic bacteria were taken from hot springs located in the Sumatra provinces of West Sumatra and Riau. Strain LBKURCC218 isolated from Rimbo Panti hot springs in West Sumatra was chosen to further investigate antimicrobials production. Isolates of hot spring bacteria that produced the highest antimicrobial were identified by comparing the similarity of the 16S rRNA gene sequences. BLAST result and phylogenetic tree showed that the selected thermophilic bacterial strain was similar to Bacillus paramicoides with the similarity index of 99.93%. Analysis of bioactive compounds of the ethyl acetate extract of liquid cultures of B. paramycoides LBKURCC218 showed the best producer of antimicrobial compounds compared to other isolates. The most identified compounds from the ethyl acetate extract were Dodecanoic acid, representing 23.62% of the total compounds, followed by 11-Dodecanoic acid at 17.84%. Ethyl acetate extract of B. paramycoides LBKURCC218 has a high inhibition zone against Escherichia coli, Staphylococcus aureus, and Candida albicans

Determine The Optimal Sequence - dependent Setup Cost and / or Setup Time for Single Demand with Multiple Products Using Modified Assignment Method

Sequencing is the most impact factor on the total setup cost and / or time and the products sequences inside demands that consist from muti-products . It is very important in assembly line and batch production . The most important drawback of existing methods used to solve the sequencing problems is the sequence must has a few products and dependent setup cost or setup time . In this paper we modify the assignment method –based goal programming method to minimize the setup cost and / or setup time. The main advantage of this new method , it is not affected by the number of products in the sequence and can treatment the sequence problems with two or more objectives . Keywords: products sequences , setup cost , setup time , travel salesman problem (TSP ) , modified assignment method , goal programming