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Grain Refinement in a Low Carbon Steel Through Multidirectional Forging

Journal of Iron and Steel Research International 2012年第10期19卷 74-78页

作者： v soleymani B Eghbali Department of Materials Science Engineering Sahand University of TechnologyTabriz 51335Iran

Grain refinement is one of the successful and low-cost methods to develop metals having excellent combination of strength and ductility. Low carbon steel was deformed by using multidirectional forging (MDF) technique at room temperature. The influence of strain amount and annealing process on the microstructure and mechanical properties of investigated steel was studied. The grain refinement mechanism was studied by the microstructure observation. The results showed that the grain refinement was attained by multidirectional forging technique. The initial coarser grains of average 38 μm size fragmented into very fine ferrite with grain sizes of about 1.2 μm. After MDF, the strength properties improved significantly, although uniform elongation and elongation decreased with increasing strain.

关键词： multidirectional forging grain refinement annealing steel recrystallization

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Comparative induction of controlled circulation by magnesium and remifentanil in spine surgery

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World Journal of Orthopedics 2014年第1期5卷 51-56页

作者： Mohammad R Ghodraty Mohammad M Homaee Kourosh Farazmehr Ali R Nikzad-Jamnani Masoud soleymani-Dodaran Ali R Pournajafian Nader D Nader Department of Anesthesiology Tehran University of Medical Sciences Department of Public Health Tehran University of Medical Sciences Department of Anesthesiology University at Buffalo

AIM: To evaluate the efficacy of magnesium sulfate(MGS) in comparison with remifentanil for induction of relative hypotension in posterior fusion of spine(PSF).METHODS: In this randomized clinical trial, 40 patients with the American Society of Anesthesiologists Ⅰ and Ⅱ physical status undergoing lumbar PSF were randomized to receive remifentanil(REM) 0.15 μg/kg or MGS 50 mg/kg for controlled hypotension. The administering anesthesiologist was blinded to the medication. Continuous infusion was maintained at a fixed volume rate to deliver precalculated doses of either study drugs. All other aspects of anesthesia and surgery were similar in the two groups. The target mean arterial pressure(MAP) range used in this study was 60-70 mm Hg. In the course of surgery, the hemodynamic variables, volumeof blood loss, urine output, fluid intake and surgeon's satisfaction were recorded. Data was analyzed with SPSS version 13.0 and P values less than 0.05 were considered ***: Twenty patients in the MGS group and 19 patients in the REM group were studied. There was no difference between the two groups in the hemodynamic variables, blood loss, urine output, fluid requirement and surgeon's satisfaction for exposure. The target MAP was achieved in 75% of Mg and 58% of remifentanil groups. Although a higher number of patients in the REM group required nitroglycerin(42.1%) to reach the target MAP than those in the MGS group(25%), this difference was not statistically significant(P = 0.32).CONCLUSION: Our findings showed that in patients undergoing lumbar PSF surgery, remifentanil and MGS have a similar hypotensive effect and comparable amount of blood loss without any significant adverse effects.

关键词： Controlled hypotension Magnesium sulfate Remifentanil Spine surgery Blood loss

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Optimization of Bead Geometry in CO<sub>2</sub>Laser Welding of Ti 6Al 4v Using Response Surface Methodology

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Engineering（科研） 2011年第7期3卷 708-712页

作者： Ali Khorram Majid Ghoreishi Mohammad Reza soleymani Yazdi Mahmood Moradi 不详

In the presented study, the laser butt-welding of Ti 6Al 4v is investigated using 2.2 kw CO2 laser. Ti 6Al 4v alloy has widespread application in various fields of industries including the medical, nuclear and aerospace. In this study, Response Surface Methodology (RSM) is employed to establish the design of experiments and to optimize the bead geometry. The relationships between the input laser-welding parameters (i.e. laser power, welding speed and focal point position) and the process responses (i.e. welded zone width, heat affected zone width, welded zone area, heat affected zone area and penetration depth) are investigated. The multi-response optimizations are used to optimize the welding process. The optimum welding conditions are identified in order to increase the productivity and minimize the total operating cost. The validation results demonstrate that the developed models are accurate with low percentages of error (less than 12.5%).

关键词： Laser Welding Response Surface Method (RSM) Optimization Ti 6Al 4v

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