This work investigates the effect of the gas nitriding process on the surface layer microstructure and mechanical properties for steel 37, tool steel X155CrVMo12-1 and stainless steel 316L. Nitriding was conducted at a temperature of 550 °C for 2 hours during the first stage and at 750 °C for 4 hours during the second stage. SEM and X-ray diffraction tests were performed to evaluate the microstructural features and the major phases formed after surface treatment. SEM and X-ray diffraction tests were performed to assess the microstructural features and the primary phases formed after surface treatment. The new secondary precipitates were identified as γ′-Fe4N, ε (Fe2–3N), and α-Fe, exhibiting an uneven chain-like pattern within columnar grains. A significant increase in the nitride layer thickness (34.4 µm) was achieved for X155 compared to AISI 316L and steel 37. Also, Gas nitriding caused a significant increase in hardness at the first stage for X 155 tool steel and AISI316L steel with hardness percentage enhancement of 0.87%(655HV) and 0.28% (219HV) respectively, while for steel37 samples the hardness reached its maximum value of 340HV for the second nitriding stage with hardness percentage enhancement of 0.78%. There was no significant improvement in surface hardness after second nitriding stages for X155 and AISI 316L steels. The effects of time and gas flow rate during the process were particularly evident on hardness values, especially after the first stage.
Two compounds,[2-amino-4-(4-nitro phenyl) 1,3-thiazole],(4) and [2-amino-4-(4-bromo phenyl) 1,3-thiazole],(5), were synthesized by refluxing thiourea (1) with each of para-ntiro and para-bomophanacyl bromides(2) and (3) respectively, in absolute methanol. Then, by reaction of [5] with 3,5-dinitrobenzoyl chloride in dimethylformamide (DMF) yielded (6) .On the other hand, reaction of (4) with chloroacetyl chloride in dry benzene afforded (7), which is upon treatment with thiourea in absolute methanol, af
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This Research aims to define role of the system of evaluating the performance for higher leadership in determining the level of institutional work quality in the Ministry of Agriculture, by measuring system efficiency of evaluating the performance for higher leadership and its effect in institutional work quality, the searcher reached through the theoretical framing and involved studies to build default plan define the relation between Research variables formed from system of evaluating leadership performance as independent variable contains six subsidiary dimensions: (Polarization, evaluating the performance of personnel, training, motivation, se
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In the present work, thermal diffusivity and heat capacity measurements have been investigated in temperature range between RT and 1473 K for different duplex stainless steel supplied by Outokumpu Stainless AB, Sweden. The purpose of this study is to get a reliable thermophysical data of these alloys and to study the effect of microstructure on the thermal diffusivity and heat capacity value. Results show the ferrite content in the duplex stainless steel increased with temperature at equilibrium state. On the other hand, ferrite content increased with increasing Cr/Ni ratio and there is no significant effect of ferrite content on the thermal diffusivity value at room temperature. Furthermore, the heat capacity of all sam
... Show MoreThis paper studies the behavior of axially loaded RC columns which are confined with carbon fiber reinforced polymers’ sheet (CFRP) and steel jackets (SJ). The study is based on twelve axially loaded RC columns tested up to failure. It is divided into three schemes based on its strengthening type; each scheme has four columns. The main parameters in this study were the compressive strength of the concrete and steel reinforcement ratio. Furthermore, the results of the experimental test showed a substantial enhancement in the column's load-carrying capacity. When compared to the original columns, the CFRP sheet had a significant effect on improving the ductility of the column by increasing the axial deformation by about 59.2 to 95.7
... Show MoreIt is suitable to use precast steel-concrete composite beams to quickly assemble a bridge or a building, particularly in isolated regions where cast-in-situ concrete is not a practical option. If steel-concrete composite beams are designed to allow demountability, they can also be extremely useful in the aftermath of natural disasters, such as earthquakes or flooding, to replace damaged infrastructure. Furthermore, rapid replacement of slabs is extremely beneficial in case of severe deterioration due to long-term stressors such as fatigue or corrosion. The only way to rapidly assemble and disassemble a steel-concrete composite structure is to use demountable shear connectors to connect/disconnect the steel beams to/from the concrete slab. I
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The phenomenon of financial and administrative corruption is not the result today, but not tied to time or designated place, he is the scourge is rampant in all countries of the world, without exception, those developed and developing, a phenomenon that crossed national boundaries and become withstand a global character, and corruption is limited to communities of particular economic systems without the other, but suffered Throughout history most societies to varying degrees, Iraq is one of the countries that suffered and continues to suffer from corruption, which has become, B grumble in most of the Iraqi state institutions, especially after the occupation in 2003 as administrative corruption in Iraq arrived i
... Show MoreThe interactions of drug amoxicillin with maltose or galactose solutions with a variation of temperature have been discussed by taking in the volumetric and viscometric procedures. Physical properties [densities (ρ) and viscosities (η)] of amoxicillin (AMOX) aqueous solutions and aqueous solutions of two type saccharides (maltose and galactose 0.05m) have been measured at T = (298.15, 303.15 and 308.15) K under atmospheric pressure. The apparent molar volume (ϕv cm3mole-1) has been evaluated from density data and fitted to a Redlich-Mayer equation. The empirical parameters of the Mayer-Redlich equation and apparent molar volume at infinite dilution ذv were explicated in terms of interactions from type solute-solvent and solute
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