Ceramic to metal joining technique, which was used in this investigation includes the use of active filler alloy as a sandwich between the alumina and kovar alloy for brazing. High purity powdered metals of silver, copper, and additives of titanium were used to prepare the active filler alloy, through compacting the mixed powders and alloying in a furnace with argon atmosphere at the temperature of 800oC for 10 minutes. To use it as an active filler metal, it has been modified to a proper thickness. Two groups of alumina were prepared with different sintering temperatures (1450oC and 1650oC) and each group was tested under atmospheric pressure, vacuum furnace pressure of 2*10-4 torr and vacuum furnace pressure of 2*10-6 torr. All the process was at a same brazing temperature of 850C for 20 minutes. A reliable joint between the different types of alumina and kovar alloy was achieved by using vacuum furnace. On the other hand, weak bond was obtained by using atmospheric furnace. A maximum value of joint strength between alumina and kovar was obtained (130 MPa) under condition of 2*10-6 torr of vacuum furnace
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DBN Rashid, Journal of Education College Wasit University 1(1):412-423, 2007
The main object of this paper is to study the representations of monomial groups and characters technique for representations of monomial groups. We refer to monomial groups by M-groups. Moreover we investigate the relation of monomial groups and solvable groups. Many applications have been given the symbol G e.g. group of order 297 is an M-group and solvable. For any group G, the factor group G/G? (G? is the derived subgroup of G) is an M-group in particular if G = Sn, SL(4,R).
The service system has become a necessity of life in modern cities to be the most basic necessities of modern humans, they constitute a major base, which is based on the sustainability of life in the city and a standard measured through the degree of well-being and progress of civilized peoples and their interaction with the surrounding environment, making the services sector as a need not be an option, whenever the cities widened in population and space whenever provision of services and upgrading the quality and quantity more pressing, which made the subject of the services takes the biggest area of the trends and thinking of urban planners and those who in charge of drawing the cities policies. Consideri
... Show MoreStarting with a problem of the weakness of accounting disclosure in some companies administration when preparing and presenting the financial reports which are submitted to the Tax authority. This problem impacts on Tax authority performance (The effect on the quality of the performance of the tax authority), because of the lack of conviction for the information contained in those reports, and the failure to achieve accurate results in tax authority performance that leads to a negative impact on determining taxable income and affect tax revenue, as well as negative impact on determining taxable income and affect tax revenue, as well as negati
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Extraction and Description of Urease Enzyme Produced from Staphylococcus saprophyticus and study of its effect on kidney and bladder of white mice
An experiment was conducted using pots (capacity of 4 kg soil/pot) in the glasshouse of Biology Dept. College of Education (Ibn Al-Haitham) University of Baghdad during 2008-2009 growing season, in order to determine the effect of different levels of urea fertilizer (Zero, 0.1, 0.2, 0.4 gm/4 kg soil in pot) these equal to (Zero, 100,200,400 kg/ha) and different levels of superphosphate fertilizer (Zero, 0.1, 0.2 gm/4kg soil in pot), these equal to (Zero, 100,200 kg/ha) on some morphological and physiological characteristics of fenugreek plant. This experiment was conducted using Completely Randomized Design (CRD) with three replications and the experiment included (36) pots. Results indicated clear increase in all studied characteristics wi
... Show MoreThe effect of chronic exposure to two different levels of cadmium chloride (CdCl2) 30 ppb and 40 ppb in drinking water for 12 weeks on thyroid function of mature male rabbits was studied. Eighteen mature male rabbits were randomly divided into three groups (each of six ) , control group (group I ): were offered ordinary tap water , and treated groups (II and III ) were offered tap water containing 30ppb and 40 ppb respectively for 12 weeks .Serum concentration of thyroxin (T4 ) and triiodothyronine (T3) were measured every six weeks ,as an index of thyroid function , further more , section of thyroid gland were prepared for histological studies. The results showed that chronic exposure of male rabbits
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This paper presents a numerical simulation of the flow around elliptic groynes by using CFD software. The flow was simulated in a flume with 4m long, 0.4m wide, and 0.175m high with a constant bed slope. Moreover, the first Groyne placed at 1m from the flow inlet with a constant the Groyne height of 10cm and a 1cm thickness, and the width of Groynes equals 7cm. A submergence ratio of the elliptic Groynes of 75% was assumed, corresponding to a discharge of 0.0057m3/sec. The CFD model showed a good ability to simulate the flow around Groynes with good accuracy. The results of CFD software showed that when using double elliptic Groy
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This study was carried out in order to determine the toxic, mutagenic and antimutagenic effects for Mallow (Malva parviflora) in comparison to its mutagenic effect of Ultraviolet (UV) because it is consider physical mutagen by using parameters for the extract pri , with , post UV exposure by using bacterial system (G-system). The used system consisted of three isolates G3 Bacillus spp., G12 Arthrobacter spp. and G27 Brevibacterium spp.. The study depended on recording survival fraction (Sx) for studying the effects and induction of Streptomycin and Refampicin resistance mutants as a genetic markers.Water Extract was prepared from fresh and dry mallow leaves, stems, flowers and roots, in optimum concentration equal to (125µg/ml) which is
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