Resistance spot welding (RSW) aluminum alloys has a major problem of inconsistent quality from weld to weld, because of the problems of the non-uniform oxide layer. The high resistivity of the oxide causes strong heat released which influence significantly on the electrode lifetime and the weld quality. Much effort has been devoted experimentally to the study of the sheet surface characteristics for as-received sheet and surface pretreatment sheet by pickling in NaOH and glassblasted with three thicknesses (0.6, 1.0, and 1.5 mm) of AA1050. Three different welding process parameters energy setup as a low, medium, and high were carried. Tensile-shear strength tests were performed to indicate the weld quality. Moreover, microhardness tests, macro/micrographs, and
SEM/EDS examinations were carried out to analyze, compare, and evaluate the effect of surface conditions on the weldability. The as received sheet showed a higher electrical contact resistance because of its thicker and non-uniform oxide layer. In contrast, the glass-blasted sheet showed lower value, since it has a roughest surface, which leads to easy breakdown the oxide layer. The highest average values and least scattering of the maximum load fracture are with treated sheet by
pickling in NaOH, these values are 760, 1193, and 2283 N for 0.6, 1.0, and 1.5 mm sheet thickness respectively for medium input energy. In contrast, the minimum values with glass-blasted sheet are 616, 1008, and 2020 N for 0.6, 1.0, and 1.5 mm sheet. The microhardness profiles of the fusion zone and HAZ is the lower than the base metal for all cases. Numerical simulation with SORPAS® was used to simulate and optimize the process parameters, and it has given good results in prediction when they compared with experiments.
Nathaniel Hawthorne (1804-1864) has been widely known for his special interest in the female characters. In many of his novels, he narrates the conditions, values, and the institutions that surround and control the life of women, leading them to be victims. In “Rappaccini’s Daughter” (1844), the heroine, Beatrice is created to be victimized by her loved ones (her father and lover). This paper focuses on the term “victim,” it shows its aspects through the development of Beatrice’s character. The paper also studies a female character in the male-dominated society, to show the cruelty done to her, and how she is considered to be a second rate person, who is unable to live normally, or at least to save herself from dea
... Show MoreDiverting river flow during construction of a main dam involves the construction of cofferdams, and tunnels, channels or other temporary passages. Diversion channels are commonly used in wide valleys where the high flow makes tunnels or culverts uneconomic. The diversion works must form part of the overall project design since it will have a major impact on its cost, as well as on the design, construction program and overall cost of the permanent works. Construction costs contain of excavation, lining of the channel, and construction of upstream and downstream cofferdams. The optimization model was applied to obtain optimalchannel cross section, height of upstream cofferdam, and height of downstream cofferdamwith minimum construction cost
... Show MoreBackground: Orthodontic tooth movement is characterized by tissue reactions, which consist of an inflammatory response in periodontal ligament and followed by bone remodeling in the periodontium depending on the forces applied. These processes trigger the secretion of various proteins and enzymes into the saliva.The purpose of this study was to evaluate the activity of alkaline phosphatase (ALP) in saliva during orthodontic tooth movement using different magnitude of continuous orthodontic forces. Materials and Methods: Thirty orthodontic patients (12 males and 18 females) aged 17-23 years with class II division I malocclusion all requiring bilateral maxillary first premolar extractions were randomly divided into three groups according to t
... Show MoreBovine milk is one of the richest nutrients that contain minerals and vitamins that enhance immunity, especially in children, but because many children do not want to drink the raw milk, therefore this study aimed to enhance the sensory characteristics of raw milk by using hibiscus plant extract, which is characterized by red color and distinctive flavor as well as studying the effect of aqueous extract of Hibiscus sabdariffa on inhibiting the growth of microorganisms, by using three concentrations of the aqueous extract (0.5, 1.0 and 1.5%), where the statistical results showed a significant difference (P≤0.05) between the concentrations in color, texture and general acceptance, and the best results appeared when using
... Show MoreThe aim of this study was to increasing natural carotenoides production by a locally isolate Rodotorula mucilagenosa M. by determination of the optimal conditions for growth and production of this agents, for encouragest to use it in food application permute artificial pigments which harmfull for consumer health and envieronmental. The optimal condition of carotenoides production from Rhodotorula mucilaginosa M were studied. The results shows the best carbon and nitrogen source were glucose and yeast extract. The carotenoids a mount production was 47430 microgram ̸ litter and 47460 microgram ̸ litter, respectively, and the optimum temperature was 30°C, PH 6, that the carotenoides a mount was 47470 microgram ̸ litter and 47670 microgr
... Show MoreABSTRACT
The effect of adding raw bacteriocin produced by Lactobacillus bulgaricus to cheese curd at an amount of (5 and 10 and 15) mL/kg cheese as a biological preservative to prolong the shelf life of soft cheese, in addition to the control treatment, knowing that each 1 mL of bacteriocin filter contains 15 units/ mL of bacteriocin. The results of the physicochemical, microbial and sensory tests for cheese stored at refrigerator temperature for a period (zero) to (21) d of adding bacteriocin showed the superiority of the treatment of cheese added to 15 mL/kg cheese of bacteriocin over the rest of the other treatments during the storage period, wh
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