A study on the different finite element approaches for laser cutting of aluminum alloy sheet

The effectiveness of finite element simulation techniques for laser cutting of 1.2-mm-thick aluminium sheets has been studied. Lagrangian and Arbitrary Lagrangian-Eulerian techniques were used to model and simulate laser cutting process. The reliability of finite element results were evaluated by general energy balance analysis and experimental results. Temperature and stress distribution along with heat-affected zone were predicted during the laser-induced process in line with experimental conditions under ABAQUS finite element code. Heat transfer analysis relying on thermal loading was employed to reach the best efficiency. By using field-emission scanning electron microscope, morphological, structural, and elemental changes in the cutting sections were analyzed along with the X-ray diffraction technique. Obtained stress and heat-affected zone are highly dependent on the element type as well as numerical method. Both numerical method, ALE and Lagrangian, are compared to each other in terms of power absorption, cut surface morphology, and cutting efficiency. The results show that ALE method is in good agreement with experimental data. A study on the different finite element approaches for laser cutting of aluminum alloy sheet. Available from: https://www.researchgate.net/publication/317579195_A_study_on_the_different_finite_element_approaches_for_laser_cutting_of_aluminum_alloy_sheet [accessed Jul 3, 2017]

Investigating the Effect of Zinc Chloride to Control External Bleeding in Rats

Background: Despite all progresses in surgical science, bleeding caused by traffic accidents is still a challenge for surgeons to save patients’ lives. Therefore, introducing an effective method to control external bleeding is an important research priority. Objectives: This study aimed to compare haemostatic effect of zinc chloride and simple suturing to control external bleeding. Materials and Methods: In this animal model study, 60 male Wistar rats were used. An incision (two cm in length and half a cm in depth) was made on shaved back of rats. The hemostasis time was measured once using zinc chloride with different concentrations (5%, 10%, 15%, 25%, and 50%) and then using simple suturing. Skin tissue was assessed for pathological changes. Due to abnormal distribution of variables in Kolmogorov-Smirnov test, the data was analyzed using Kruskal-Wallis test Mann-Whitney U tests. Results: In all the groups, complete hemostasis occurred. Hemostasis times of different concentrations of zinc chloride were significantly less than that of the control group (P < 0.001). Conclusions: Zinc chloride was effective to control external bleeding in rats

A Comparison Between Foley and Nelatone Urinary Catheters in Causing Urinary Tract Infection in Animal Models

Background: Urinary catheterization is one of the main measures used to treat and care for hospitalized patients. Several complications have been attributed to the presence of latex with routine Foley catheters. Therefore, some studies have recommended that Nelatone catheters be substituted for the ordinary Foley catheters to prevent these complications. Objectives: This study aimed to compare the rates of urinary tract infection (UTI) in rabbits catheterized either with Foley or with Nelatone catheters. Materials and Methods: A randomized controlled trial was conducted on 60 rabbits that were randomly assigned to three groups of twenty. The first group was catheterized using Nelatone catheter; the second group was catheterized using Foley catheter and the third group was studied without performing any catheterization. After seven days, urine samples were collected using suprapubic aspiration and were sent to the laboratory for culture. Descriptive statistics were calculated. Moreover, chi-square and Fisher’s exact tests were used for data analysis. Results: At the end of the study, four 4 cases in the Nelatone group and 12 cases in the Foley group presented with UTI (P = 0.01). No positive urine cultures were found in the control group. Conclusions: The Nelatone catheters, compared with the Foley ones, had a lower risk of UTI in the long term use. Verifying this claim by further studies can have an important role in reducing UTIs in patients using urinary catheters

Comparative study on some physiologic, biometrics, nutritional value and molecular characteristics of Mighan Lake’s Artemia (Arak)

Due to the importance of identifying the major characteristics of Artemia populations, in this study some physiologic, biometric, nutritional and genetic characteristics of one Artemia population from Iran named Arak’s Artemia (Mighan Lake) was studied. The hatched larvae of Artemia were reared in the saline water of 80 g/l with standards method in which percentage of survival and growth were evaluated on days 3, 7, 11 and 15 of culture period. In order to study the morphometric characteristics of Artemia, diameter of full cysts as well as 11 more morphological parameters of adult Artemia were measured. The fatty acid profile was analyzed by gas chromatography. The Genetic characteristics were compared with other Artemia populations by sequencing after PCR amplification of Hsp 26 gene. According to the results, the diameter of cysts and nauplii instar were 276.28 and 544.66 micron, respectively. The growth and survival of brine shrimp Artemia, in comparison with other populations, reflected good growth and survival of this population. The results of fatty acids profile also showed higher amounts of polyunsaturated fatty acids in this Artemia compared to other populations cultured under identical conditions. The morphometric characteristics and genetic study of Hsp 26 gene showed great affinity of this population with the parthenogenetic brine shrimp Artemia. However, individual differences could be used to characterize this population