This paper demonstrates an experimental and numerical study aimed to compare the influence of openings of different configurations on the flexural behavior of prestressed concrete rafters. The experimental program consisted of testing six simply supported prestressed concrete rafters; 5 rafters are perforated, and the other one is solid as a reference. All rafters were tested under monotonic midpoint load. The variable which has been investigated in this work was the opening’s configuration (quadrilateral or circular) with the same upper and lower chords depths. The results indicate improvement in the beam flexural behavior using the circular openings compared to the quadrilateral o
Heat treatment by solid solution method in the ?+? phase region was used at 970°C for Ti-5Al-2.5Fe alloy. The specimens cooled under different cooling media [water quenched (WQ), air cooled (AC) and furnace cooled (FC)], and subsequently aged at 550°C for 4 hours. Five specimens from each treatment were immersed in simulated body fluid SBF for a period of time (3 months). The dependence of corrosion rate on compositional variation in the phases resulted from various type of cooling rates are discussed based on immersion tests. The EDXA results show the precipitation of phosphate and calcium compounds on the alloy after 3 months of immersion in blood plasma solution forming a bone-like apatite, which enhanced the alloy biocompatibility ma
... Show MoreCorrosion resistance of metals is one of the most important topics for researchers. In this work, epoxy-TiO2 nanocomposite has been developed for protection of 6061AL alloy. The dip-coating technique used to deposit the coating on 6061 Al alloy substrate. Different concentrations of TiO2 NPs (1,3,5 )Wt% have been used to study the corrosion behavior in 3.5% NaCl medium. Also, 200,150 and 100 mm/min dipping speeds have been employed for 1%wt TiO2 to show their effects on coating layer and corrosion rate. Characterization of coated surfaces were investigated by AFM, FESEM andEDS,while theelectrochemical measurementswas using to evaluate protective nature of the coating. The results have shown that the corrosion rate has decreased with
... Show MoreThis research concern to analyse and simulate the temperature distribution in the spot welding joints using tungsten arc welding shielded with inert gas (TIG Spot) for the aluminum-magnesium alloy type (5052-O).
The effect of and the quantity of the heat input that enter the weld zone has been investigated welding current, welding time and arc length on temperature distribution. The finite element method (by utilizing programme ANSYS 5.4) is presented the temperature distribution in a circular weld pool and the weld pool penetration (depth of welding) through the top sheet ,across the interface into the lower sheet forming a weld spot. &nbs
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The nanocompsite of alumina (Al2O3) produced a number of beneficial effects in alloys. There is increasing in resistance of materials to surface related failures , such as the mechanical properties , fatigue and stress corrosion cracking .The experimental results observed that the adding of reinforced nanomaterials type Al2O3 enhanced the HB hardness, UTS, 0.2 YS and ductility of 2014 Al/Al2O3 nano composites . the analysis of experiments, indicated that The maximum enhancement was observed at 0.4 wt.% Al2O3. The ultimate improvement percentage were 15.78% HB hardness, 18.1% (UTS), 12.86% (
... Show MoreCommercially pure titanium (cpTi) is widely used as dental implant material although it was found that titanium exhibited high modulus of elasticity and the lower corrosion tendency in oral environment. Niobium(Nb) was chosen for this study as an alternative to cpTi implant material due to its bioinert behavior and good elastic modulus and moderate cost in addition to corrosion resistance. This study was done to evaluate the effect of biomimetic coating on the surface properties of the commercially pure titanium and niobium implants by in vitro and in vivo experiments. The in vitro study was involved etching the samples of each material in HCl then soaking in 10M NaOH aqueous solution. These samples were then immersed in a 5 times concent
... Show MoreHigh performance work systems and general industrial enterprise performance
A phosphorus‐containing Schiff base was prepared from bis{3‐[2‐(4‐amino‐1,5‐dimethyl‐2‐phenylpyrazol‐3‐ylideneamino)ethyl]indol‐1‐ylmethyl}phosphinic acid and paraformaldehyde as a novel antibacterial compound. The reaction of the Schiff base ligand with VO(IV), Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(IV) led to binuclear species of metal complexes, depending on the ratio of metal ion and ligand. The ligand and its complexes were investigated using elemental analysis, Fourier transform infrared, 1H NMR, 13C NMR, UV–visible and mass spectra, thermogravimetric analysis, conductivity measurements and thermal analysis. The results showed that the S
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The issue of inequality in distribution of income and / or consumption expenditure is related to economic welfare because there is an inverse relationship between the economic welfare on the one hand, and the degree of inequality, on the other hand. Despite the fact that inequality is considered as normal phenomenon in every society, but if it exceeded certain limits it will lead to undesirable economic, social and political consequences. Therefore, the availability of indicators about inequality is a necessary tool for planning and evaluation of economic development programs. So, current study is aiming at measuring and analyzing the degree of inequality in distribution of consumpti
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