Materials and Energy Research CenterInternational Journal of Engineering1025-249518120050201Experimental Investigation of Boiling and Condensation Heat Transfer of a Two Phase Closed Thermosyphon11071561ENM. KhoshnoodiChemical & Petroleum Engineering, University of Sistan & BaluchestanM.H. KalaeiChemical & Petroleum Engineering, Ferdowsi University of MashhadS.H. NoieChemical & Petroleum Engineering, Ferdowsi University of MashhadJournal Article19700101In this paper the heat transfer characteristics of a two-phase closed thermosyphon over a wide range of heat transfer rates, system pressure, aspect ratios and filling ratios were studied. The experiments focused on the boiling and condensation heat transfer characteristics of a thermosyphon with a copper tube having 25 and 32 mm inside and outside diameters. Distilled water was used as the working fluid. The experimental boiling and condensation heat transfer coefficients inside the thermosyphon were compared with the existing correlations. A good agreement between the experimental results of condensation heat transfer of the thermosyphon and Nusselt’s correlation was obtained. In addition, the optimal working fluid filling and the overall heat transfer coefficient were evaluated for practical operation. Finally, according to poor agreement between the experimental results of boiling heat transfer coefficient and existing correlations, the working conditions were analyzed and a new practical formula (correlation) was presented. The new correlation can be used to predict boiling heat transfer coefficient generally.Materials and Energy Research CenterInternational Journal of Engineering1025-249518120050201Comparison of Exact Analysis and Steplines Approximation for Externally Excited Exponential Transmission Line112071564ENA. CheldaviElecterical Engineering, Iran University of Science & TechnologyJournal Article19700101In the present paper, the problem of externally excited exponential transmission line hasbeen solved analytically in frequency domain using a simple approach. Then steplines approximationas a first order approximation for the problem of externally excited nonuniform transmission lines ingeneral and exponentially tapered transmission line (ETL) as a special case has been presented.Finally the two approaches are compared and some useful results are obtained to show when the twomethods are equivalent.Materials and Energy Research CenterInternational Journal of Engineering1025-249518120050201State Dependent M/M/C/K/N Machining System with Mixed Spares and Removable Repairmen212871565ENG. C. SharmaMathematics, I.B.S, AGRASharon MosesMathematics, Dr.B.R.Ambedkar Open UniversityMadhu JainDepartment Of Mathematics, IIT Roorkee,Roorkee,IndiaJournal Article19700101Materials and Energy Research CenterInternational Journal of Engineering1025-249518120050201Stall Vortex Shedding Over a Compressor Cascade (RESEARCH NOTE)293671569ENNima AmanifardMechanical Engineering, University of GuilanJournal Article19700101The unstable flow with rotating-stall-like (RS) effects in a rotor-cascade of an axialcompressor was numerically investigated. The RS was captured with the reduction in mass flow rateand increasing of exit static pressure with respect to design operating condition of the single rotor.The oscillatory velocity traces during the stall propagation showed that the RS vortices repeatperiodically, and the mass flow rate was highly affected by the blockage areas made by stall vortices.The results also showed that large scale vortices highly affects on the generation and growth of thenew vortices. An unsteady two-dimensional finite-volume solver was employed for the numericalstudy which was developed based on Van Leer’s flux splitting algorithm in conjunction with TVDlimiters and the flow rate with the experimental results validates the numerical study.κ-ε turbulence model was also employed. The good agreement of the computed massMaterials and Energy Research CenterInternational Journal of Engineering1025-249518120050201A Computational Study of Oxygen Transport in the Body of Living Organism (RESEARCH NOTE)394471571ENN. KumarMathematical / Computer Science and Engineering, Poornima University, Jaipur, IndiaSanjeev KumarMathematics, IBS, Khnadari, AgraJournal Article19700101Oxygen is an essential part of the living organism. It is transported from blood to the body tissue by the systematic circulation and large part of it is stored in the blood flowing in capillaries. In this work we discuss a mathematical model for oxygen transport in tissues. The governing equations are established assuming that the blood is flowing along a co-axial cylindrical capillary inside the tissue and has a constant partial pressure of oxygen. We solve the governing partial differential equations using finite element techniques. The main object of the present work is to investigate the effects of various assumptions such as neglecting axial diffusion and neglecting the effect of facilitated myoglobin diffusion.