فهرست مطالب سید احمد جنابعلی جهرمی

Engineering ethics deals with moral issues and decisions confronting individuals and organizations engaged in engineering, and it is, therefore, the ability and the responsibility of all engineers to evaluate their decisions based on the general well-being of a society. Aim of the present study was to identify and rank the components of engineering ethics. This study is categorized as applied research based on the aims, and descriptive research in terms of the methods and nature of the study. To collect the data, questionnaires were prepared based on multi-attribute decision-making methods and completed by five managers of technical and engineering service provider organizations in Bushehr; the managers had at least five years of management experience and presence in this profession. The data were analyzed by SuperDecisions software. The results of this study show the components of accountability, adherence to rules and regulations, and adherence to public welfare and environment are the most important components of engineering ethics. In general, it can be concluded that organizational components have had a far more important role than professional and individual ethics components.

Al-Zn-Mg/3 wt-% Al2O3 nanostructured composite powder was synthesized through Mechanical Alloying (MA). At first, the 7014 alloy matrix constituents were milled in a planetary ball mill for 20 hours. Then, 3 wt.% µ-Al2O3 particles were added to the pre-milled matrix and the nanostructured composite powder was produced at different MA times to investigate the effects of MA time on the characteristics of the produced composite powders such as morphology, crystallite size, lattice strain and microhardness. The characterization results proved that synthesizing nanostructured composite powder with a low amount of micrometric reinforcements in addition to pre-milled micrometric matrix is possible. Also, synthesis of the nanostructured composite powder with the minimum crystallite size of 24 nm and the minimum mean particle size of 5 µm was confirmed. Moreover, the steady state occurred after around 20 hours milling and further milling did not affect the powder characteristics excluding crystallite size, lattice strain and microhardness. In addition, sinterability of the composite powders increased with increasing the milling time due to decreased average particle size. However, after the steady state, the sinterability did not change.

In the present research, the finite element analysis of the surface transformation hardening in the vicinity of workpiece discontinuity was performed both thermally and metallurgically using ABAQUS finite element software. In order to predict the volume fraction of the obtained phases and the hardness profile during continuous cooling stage, the appropriate user-defined subroutine based on the Kirkaldy kinetic model was employed in the data flow of the software. Besides the effects of different controlling strategies and the application of a quenching medium at the discontinuity surface was investigated. Based on the obtained results, these strategies which are based on controlling the input power and travelling speed of the heat source as a function of the maximum temperature at the surface, allows for gaining a more uniform thermal history at the surface. However, as these strategies could not control the cooling rate in the vicinity of discontinuities, applying a quenching medium with an optimum cooling power is essential in order to achieve a uniform hardened layer at the workpiece depth.

So far، most of the researches have examined the production process and its effect on the properties of epoxy nanocomposites and there is little informations on the nanocomposite with vinyl ester polymeric matrix. However، vinyl ester is one of the highly used resins in composite industry. In recent years، adding reinforcements with small dimensions (especially in nanoscale) has been proposed as a solution to improving the properties. In nanocomposites، due to diffusion of polymer chains into the nanoparticles and establishment of an appropriate bond with them، improvment of the properties can be expected. The aim of this research was to manufacture and investigate of tensile behavior of vinyl ester/titanium dioxide nanocomposites. Nanocomposite samples were produced by melt mixing technique and with content of 1، 2. 5 and 5 weight percent of TiO2 nanoparticles. In addition، BYK-C8000 was added to the mixture as polymeric coupling agent. At first، the influence of production parameters on the properties of vinyl ester/1%wt. TiO2 nanocomposite was evaluated and then with selecting the optimum conditions and fixing the manufacture parameters، the effect of nanoparticles content on the properties of the samples was studied. Tensile behavior of nanocomposite was evaluated by uniaxial tensile test. Results indicate that by increasing in TiO2 content in the polymer matrix، the Young''s modulus steadily increases; while the strain-to-break of nanocomposites is reduced compared to the pure specimen.