Static loads exposing to mechanical components can cause cracks, which are lead to form stress concentration regions causing the failure of structure. Generally, from 80% to 90% of structure failure is due to initiation of the cracks. Therefore, it is necessary to repair the crack and reduce its effect on the structure where the effect of the crack is modelled as an additional flexibility to the structure. In the last few years, piezoelectric materials have been considered as one of the most favourable repairing techniques. The piezoelectric material converts the applied voltage on it to a bending moment to counter the bending moment caused by the external load on the beam at the crack location. In this study, the design of the piezoelectric materials used to repair effect of crack on the mechanical behaviour of beam subjected to static loads is analytically achieved. This design includes calculating of desired dimensions of the material with the required voltage applied on it. The additional flexibility is expressed in term of a proposed unitless factor which can be calculated depend on experimental work. The results show that increasing the patch thickness increases the beam resistance to crack and load effects, while increasing the length of the piezoelectric material reduces the magnitude of the voltage required to repair the cracked beam.
New microphotometer was constructed in our Laboratory Which deals with the determination of Molybdenum (VI) through its Catalysis effect on Hydrogen peroxide and potasum iodide Reaction in acid medium H2SO4 0.01 mM. Linearity of 97.3% for the range 5- 100 ppm. The repeatability of result was better than 0.8 % 0.5 ppm was obtanined as L.U. (The method applied for the determination of Molybdenum (VI) in medicinal Sample (centrum). The determination was compared well with the developed method the conventional method.
Objective: Schiff’s and Mannich bases of isatins are an important group of heterocyclic compounds which are of great importance in medicinal chemistry as antimicrobial agents. In the vision of these facts, new bis-Schiff bases and Mannich bases of isatins were synthesized. Methods: Three different bis-Schiff bases (3a-c) have been synthesized by reacting isatin, 5-fluoroisatin and 5-methoxy isatin with thiophene-2- carboxaldehyde using hydrazine hydrate to link between the carbonyl compounds, and then these bis- Schiff bases were condensed with two different secondary amines (piperidine and morpholine) separately, and formaldehyde to form the Mannich bases (4a-c and 5a-f), respectively. Results: The structures of the newly synthesized com
... Show MoreEvaluation was carried out on the existing furrow irrigation system located in an open agricultural field within Hor Rajabh Township, south of Baghdad, Iraq (latitude: 33°09’ N, longitude: 44°24’ E). Two plots were chosen for comparison: treatment plot T1, which used subsurface water retention technology (SWRT) with a furrow irrigation system. While the treatment plot T2 was done by using a furrow irrigation procedure without SWRT. A comparison between the two treatment plots was carried out to study the efficiency of the applied water on crop yield. In terms of agricultural productivity and water use efficiency, plot T1 outperformed plot T2, according to the study’s final fin
Background: ?-L-Fucose is a methyl pentose sugar, had the ability to kill bacteria, controlling infection and normalize immune function. The objective of this study is to determine the effect of sulcular injection of fucose on rabbits periodontium , throughout measuring the level of some proinflammatory cytokine ; interlukine 1beta ( IL-1beta) and tumor necrosis factor ( TNF-alpha) in sera of rabbits before fucose injection and at 3 days after fucose injection. Materials and Methods: The study was carried on using ( 20 ) male rabbits of the same species weighted (1-1.5 kg ) , the blood samples were collected from hearts of 20 rabbits before fucose injection and consider as( non injected group) , and after 3 days of fucose injection and con
... Show MoreElectrodeposition of metal oxides on graphite electrodes can improve their ability to remove organic substances. In this work, multicomponent oxides of Mn, Co, and Ni were electrochemically deposited on both the anode and cathode of graphite electrodes to enhance their performance in removing phenol. Formation of the deposit was achieved within 2 h in current densities of 20, 25, 30, and 35 mA/cm2 for better composite properties. The deposited layer was characterized by testing the surface structure, morphology, composition, and roughness. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and Atomic force microscopy (AFM) techniques facilitated these tests. The composite electrodes have synthesized
... Show MoreStimulative effect of 10 mW He-Ne laser on the phagocytic activity of human polymorphonuclear leukocytes( PMNs) has been studied in vitro. Normal polymorphonuclear leucocytes were isolated from the human peripheral blood. A mixture of 0.25 ml of Hanks solution, 0.25 ml of serum, 0.25 ml of Candida albicans suspension and 0.25 ml of PMNs suspension was prepared. The samples of mixture of PMNs and Candida were subdivided in 1 ml ependrof tubes and irradiated to He-Ne laser for 1, 3, 5, 10 and 20 min. The diameter of the irradiated area was 0.8 cm. For calculation of Phagocytic index before and after irradiation, the samples were incubated (37°C) at 5, 15, 30, 60 min. The slides of samples were prepared and stained using Giemsa stain. The
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