International Journal of Academic Scientific Research
ISSN: 2272-6446 Volume 9, Issue 1 (February – March 2021)
All listed papers are published after full consent of respective author or co-author(s).
For any discussion on research subject or research matter, the reader should directly contact to undersigned authors.
Modeling The Effect of Friction Stir Welding Tool Parameters on Plunge Phase Using Arbitrary Lagrangian-Eulerian Analysis-ALE
Abdul Mounem Jesri, M. Jameel Alshehne, Shereen Hesso
ABSTRACT: A comprehensive understanding of plunge phase is an important step in the optimal design of the friction stir welding (FSW) tool, whereas it plays an effective role in the successful process in terms of sufficient heat generating and material mixing as well as avoiding breakage and wear of the tool, which in turn affects the properties of the resulting weld joint. This paper presents a non-linear, 3D thermo- mechanical coupled model that simulates the plunge phase which is considered the critical phase in the modeling, by using Abaqus/Explicit program, Based on Arbitrary Lagrangian-Eulerian (ALE) analysis with Adaptive Remesh technique, in order to analyze the effect of different tool parameters (shoulder diameter, probe diameter and its height, plunge depth) on the behavior of the plate near the tool and thus the conditions that lead to the successful of the plunge phase in terms of the critical temperature and its distribution of the FSW and stresses applied to the plate. It was found from the numerical results that the welding process with a shoulder diameter of 16 mm ,a probe diameter of 5 mm ,a height of 4.5 mm and with a plunge depth of 0.2 mm were considered the optimal parameters for the tool design that gives the required temperature, which is about (70-90%) of the melting temperature in addition to lower stresses compared to other parameters which were applied to 6061-T6 aluminum alloy at tool rotation speed of 315 Rpm, numerical results were verified by the experimental application throughout using vertical milling machine to produce the welded butt joints and followed by microstructure examination.
Prevalence of Genital Tract Lacerations During Labor
Hiba Allah Al Hammoud, Roula Zayyat
ABSTRACT: Aim of study: to determine the prevalence, demographic characteristics and pattern of lower genital tract injuries in labor at Aleppo University Hospital of Obstetrics & Gynecology.
Study design: This observational prospective study included all women who had delivered in Aleppo University Hospital of Obstetrics & Gynecology and had genital tract injury between 1/1/2019 and 1/1/2020. A total of 7459 had delivered in the hospital at that period, of which 4125 had vaginal delivery and 3334 had caesarian section.
Results: A total of 393 women (5.26 % of labors) during the study had a kind of genital tract laceration. Complete and incomplete uterine ruptures formed about 14.6% of injuries, whereas first degree perineal tears were the leading types of genital tract laceration(64%).On the other hand; third and fourth degree perineal tears were rare. It is noticed that BMI was higher in third(3b) and fourth degree of perineal tears. Also, all of third(3b) degree perineal tears were nulliparus with a mean age of(19) compared with higher ages in the other types of lacerations. It is noticed that neonatal birth weight was higher in sever degrees of perineal tears compared with mild ones. Also, the duration of expulsion stage was longer among second and third(3a)degrees of perineal tears compared with the other types of perineal lacerations.
Conclusion: Genital tract lacerations are common in labor, they were observed in 5.26% of women. Of these injuries, complete uterine rupture formed 7.8%, cervical tears 14.5% and perineal tears of first degree 61.6%. Low maternal age, nulliparity, second parity, high BMI, and high birth weight should all be noticed in labor as they have important relation with lower genital tract injuries .
[Download] PP 13-18
Bioaccumulation and translcation of metals in selected plants from fam Apiaceae
Gorica Djelic, Sinisa Timotijevic, Zoran Simic
Abstract: The paper analyzes heavy metals (Mn, Ni, Fe, Cu, Zn, Ca, Mg) in plant species Petroselinum crispum Mill., Daucus carota L., Conium maculatum L. and in the land on which they grow. The aim of the research is to determine the differences in the acceptance, distribution, and accumulation of metals between the investigated species, based on the content of metals in the plant organs (root, tree, leaf, and fruit), based on the bioaccumulation coefficient, bioconcentration and translocation factor. The atomic absorption spectrophotometer determines the amount of metal in the soil and plant material. Results showed that in the investigated soil there were the highest Fe levels, but in quantities not exceeding the maximum permitted concentrations. The content of Mn, Fe, Cu in all analyzed plants is elevated. Follows the sequence of heavy metals on the basis of total quantity in the species P. crispum Ca>Mg>Fe>Mn>Zn>Ni>Cu, and for the species D. carota, C. maculatum, Ca>Mg>Fe>Zn>Mn>Cu>Ni. There is a significant intraspecies difference in the distribution of the examined elements.
[Download] PP 19-27