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Heat Distribution (heat + distribution)
Selected AbstractsNumerical Determination of Heat Distribution and Castability Simulations of as Cast Mg,Al Alloys (Adv. Eng.ADVANCED ENGINEERING MATERIALS, Issue 3 2009Mater. The cover shows the simulated grains for Mg-10%Al, the dendritic, microstructure can be seen. More details can be found in the article of S.S. Khan on page 162. [source] Numerical Determination of Heat Distribution and Castability Simulations of as Cast Mg,Al Alloys,ADVANCED ENGINEERING MATERIALS, Issue 3 2009Shehzad Saleem Khan Magnesium alloys offer a large potential as lightweight structures especially in the automotive industry. Research and development of magnesium alloys depend largely on the metallurgist's understanding and ability to control the microstructure of the as cast part. This research work comprises the determination of experimental parameters to simulate fluidity and microstructure of magnesium/aluminum binary alloys. [source] Microdissection or Microspot CO2 Laser for Limited Vocal Fold Benign Lesions: A Prospective Randomized Trial,THE LARYNGOSCOPE, Issue S92 2000Michael S. Benninger MD CO2 lasers have become an important technological advance and an integral tool for the laryngeal surgeon since the 1960s. Surgeons have used lasers for a variety of benign and malignant lesions in the larynx with good success. With better understanding of the microarchitecture of the vocal folds and the recognition of heat distribution into surrounding tissues that occurs with the use of standard CO2 lasers, questions and concerns have been raised regarding the use of the CO2 laser for benign lesions of the vocal folds. With the advent of the microspot CO2 laser with a spot size of less than 250 ,m, the potential heat distribution to the deeper layers of the lamina propria has been reduced. The microspot CO2 laser has been suggested to be an appropriate tool for the excision of superficial benign lesions of the vocal fold and may be considered as an appropriate treatment alternative to microdissection. Only a limited number of studies have compared the efficacy of microdissection versus microspot CO2 laser surgery in the larynx, and no prospective, randomized trials have been performed. Objective This study was designed to compare microspot CO2 laser excision and microdissection for superficial benign lesions confined to the free margin of the vocal fold. Study Design: A randomized, prospective trial comparing microspot CO2 laser excision and microdissection in the removal of nodules, polyps, and mucous retention cysts of the vocal fold. Methods Acoustic and aerodynamic measures and videostroboscopic and perceptual audio recordings evaluated by a panel of blinded viewers and listeners were studied preoperatively and 2 to 3 weeks and 5 to 12 weeks postoperatively. Surgical and recovery times were compared between the two groups. Results Thirty-seven patients met selection criteria and were enrolled, 21 in the microdissection group and 16 in the laser excision group. Significant improvements in videostroboscopic parameters were found over time in both groups. Significant improvements were noted for perceptual analysis over time for the laser excision group with nonsignificant improvements over time for the microdissection group. There was no difference in any measure between laser excision and microdissection at the two postoperative visits. There was no difference in surgical or recovery time between laser excision and microdissection. Acoustic and aerodynamic parameters were noncontributory in evaluating outcomes of treatment, since most values were normal before surgery. Conclusion No differences in clinical outcomes are identified when comparing microdissection with laser excision of nodules, polyps, and mucous retention cysts of the vocal folds. [source] Numerical model for polymer electrolyte membrane fuel cells with experimental application and validationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009Javier Alonso Mora Abstract The aim of this paper is to present a simple 3D computational model of a polymer electrolyte membrane fuel cell (PEMFC) that simulates over time the heat distribution, energy, and mass balance of the reactant gas flows in the fuel cell including pressure drop, humidity, and liquid water. Although this theoretical model can be adapted to any type of PEMFC, for verification of the model and to present different analysis it has been adapted to a single cell test fixture. The model parameters were adjusted through a series of experimental tests and the model was experimentally validated for a well-defined range of operating conditions: H2/air O2 as reactants, flow rates of 0.5,1.5 SLPM, dew points and cell temperatures of 30,80 °C, currents 0,5 A and with/without water condensation. The model is especially suited for the analysis of liquid water condensation in the reactant channels. A key finding is that the critical current at which liquid water is formed is determined at different flows, temperatures, and humidity. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Vapor chemical and heat distribution.CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 9 2009Source: Corbis Digital Stock (Chem. Eng. No abstract is available for this article. [source] | ||||||||||