In this paper the effect of engagement length, number of teeth, amount of applied load, wave propagation time, number of cycles, and initial crack length on the principal stress distribution, velocity of crack propagation, and cyclic crack growth rate in a spline coupling subjected to cyclic torsional impact have been investigated analytically and experimentally. It was found that the stresses induced due to cyclic impact loading are higher than the stresses induced due to impact loading with high percentage depends on the number of cycles and total loading time. Also increasing the engagement length and the number of teeth reduces the principal stresses (40%) and
(25%) respectively for increasing the engagement length from (0.15 to 0.23) and the number of teeth from (8 to 10). while increasing the other parameters (amount of applied load, wave propagation time, number of cycles, and initial crack length) increase the principal stresses at the root of the tooth (37% when the applied load rises from (8 KN to 11KN) and (62% when the wave
propagation time rises from (0.5 to 1).
bstract The aim of this work covers the synthesis and characterization of the new tertra dentate ligand (H4L) containing (N and O) as donor set atoms kind (N2O2) where: H4L=Bis-1,2 (2,4- dihydroxybenzylediene phylinediamine . The preparation of ligand contains reaction 2, 4 - Dihydroxy benzaldehyde and o-phenylene diamine . Schiff base was reacted with some metal ions in the presence of methanol to give the complexes in the general formula [M (H2L)] where: MII = Co, Ni, Cu, Zn, Cd. All compounds were characterized by spectroscopic methods I.R , U.V.-Vis, metal content and molar conductivity measurements, showed that the complexes are non-electrolyte. The proposed geometry for all of the proposed complexes was a tetrahedral while Ni complex
... Show MoreThe Ilkhanid Mongols (651-756 AH / 1253-1355 AD) were interested in urbanization and construction in keeping with civilized countries and to have an architectural imprint that competed with the neighboring nations. The Ilkhan Öljeitü Muḥammad Khudābandeh (703-716 AH / 1303-1316 AD), known for his love of building and construction, wanted to have a capital that would immortalize his name and history, so he ordered its construction to compete with contemporary cities, and he summoned workers and engineers from all over the world to contribute to its construction. The city has several educational and service institutions such as schools, ribats, khanqas, mosques, hospitals, markets, and baths, as well as a mausoleum for him, which
... Show MoreAbstract: In the present work, the heat transfer of Nano Aluminum Oxide -NAO- has been studied practically to define the appropriate insulation conditions. This study focuses on finding of the amount of heat transfer through a glass substrate that is coated with nanoalumina doped on PMMA matrix. The optical and thermal properties were systematically investigated. The density of heat flow rate, was calculated in the range values (240-260) W/m2 while the optimum values confine between (250-260) W/m2 at temp. (25-35)Co. The results showed that the thermal insulation of the sample was significantly enhanced at temp. (30-50)Co. The simulated net heat transfer through window decreased linearly with incr
... Show MoreIn this work, prepared new ligand namely 5-(2,4-dichloro-phenyl)-1,3,4-oxadiazole-2-(3H)-thion, was obtained from the 2,4-dichlorobenzoyl chloride with hydrazine, after that reaxtion with CS2/KOH in methanol.
This study aimed to extract, purify, and characterize the protease of local Okra Abelmoschus esculentus pods. The extraction process was conducted using ten extraction solutions with different pH and ionic strength values. Phosphate buffer solution with (pH 7, 0.05M, containing 2% sodium chloride) gave the highest activity which was (7.2 Unit/ml) as compared to other solutions, which ranged from 0.8-5.9 Unit/ml. The extracted enzyme purified by several stages. Being, precipitation by gradual addition of Ammonium sulphate from 20 to 85% saturation, then the precipitated enzyme was dialyzed and fractionated through DEAE-Cellulose (22X1.1cm), the enzymic fractions were pooled. The specific activity, purification fold and the enzyme yield value
... Show MoreAbstract
Objectives: To find out the association between enhancing learning needs and demographic characteristic of (gender, education level and age).
Methods: This study was conducted on purposive sample was selected to obtain representative and accurate data consisting of (90) patients who are in a peroid of recovering from myocardial infarction at Missan Center for Cardiac Diseases and Surgery, (10) patients were excluded for the pilot study, Data were analyzed using descriptive statistical data analysis approach of frequency, percentage, and analysis of variance (ANOVA).
Results: The study finding shows, there was sign
... Show MoreThe [2-hydroxy -1,2-diphynel-ethanone oxime] was reacted with 1,2- dichloroethan to give the new ligand [H2L].this ligand was reacted with some metal ions (Co(II),Ni(II),Cu(II),Zn(II) and Cd(II) in methanol as a solvent to give a series of new (1:1)complexes of the general formula [ M(HL)]Cl ,( where : M= Co(II),Ni(II),Cu(II),Zn(II) and Cd(II)) are isolated All compounds have been characterized by spectroscopic methods [ I.R , U.V -Vis ] atomic absorption . Chloride content along with conductivity measurements. From the above data the proposed molecular structure for (Co, Cu, Ni, Zn and Cd) complexes adopting a tetrahedral structure.