@article { author = {Mehdizadeh, H. and Dickson, J. M.}, title = {Overview of Reverse Osmosis for Chemical Engineers Part 1, Fundamentals of Membrane Mass Transfer}, journal = {International Journal of Engineering}, volume = {1}, number = {4}, pages = {163-180}, year = {1988}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {Reverse osmosis (RO). has become a standard unit operation in Chemical Engineering. This separation process can be used for a wide variety of applications including: desalination of sea water, treatment of industrial wastes, concentration of food products, and recovery of value materials from solution mixtures. In order to best utilize RO it is necessary to have a fundamental understanding of the process so that the optimum design can be reached. In this first part of a two-part series, the fundamental aspects of the RO process are reviewed, several transport models are summarized and the design equations necessary for scale up are presented. The emphasis is to provide a simple, practical, and yet comprehensive summary of the most relevant information that will be needed by a chemical engineer trying to apply reverse osmosis membranes to specific applications.}, keywords = {}, url = {https://www.ije.ir/article_70988.html}, eprint = {https://www.ije.ir/article_70988_ad9c9f83b33762eaa2b91b104ba29d02.pdf} } @article { author = {Moshfeghian, M.}, title = {The Pfgc Equation of State at the Age of Fourteen}, journal = {International Journal of Engineering}, volume = {1}, number = {4}, pages = {181-192}, year = {1988}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {The purpose of this paper was to review and report the recent advances and progress that have been achieved on the fourteen year old PFGC equation of state. This paper will also discuss the good (pros) and the bad (cons) of this equation of state. Emphasis will be made on the following categories:A. Prediction of the pure component PVT properties1. Hydrocarbons in particular n-alkanes2. Selected non-hydrocarbons such as N2, H2S, CO2, H2O3. 1-Alkanols4. Refrigerants5. Coal derived constituentsB. Vapor- Liquid-Equilibrium1. Hydrocarbon systems2. Hydrocarbon + water systems3. 1 -Alkanol + water systems4. Water + acid gases ( e.g. H2S & CO2 ) systems5. 1-alkanol + n-alkane systemsC. Vapor-Liquid Hydrocarbon-Liquid water EquilibriumD. Hydrate formation and inhibition by methanol based on the basic model of Prausnitz and Parrish.In all of the above categories comparison between the experimental data and those predicted by the PFGC equation of state will be presented.}, keywords = {}, url = {https://www.ije.ir/article_70989.html}, eprint = {https://www.ije.ir/article_70989_9ce2f48f5d03528ed43ecf8bc02e7a23.pdf} } @article { author = {Irani, F.}, title = {Stability of One Bay Symmetrical Frames with Nonuniform Members}, journal = {International Journal of Engineering}, volume = {1}, number = {4}, pages = {193-200}, year = {1988}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {This paper deals with simple portal or gable steel frames with varying moment of inertia. Critical load for such frames is calculated by means of a very simple and approximate method through which the variation of moment of inertia for the members is considered by a quadratic function and then the equilibrium and continuity conditions have been used. The degree of precision of this method has been checked by a computer method in a numerical example. The method is applicable only for one bay steel frames.}, keywords = {}, url = {https://www.ije.ir/article_70990.html}, eprint = {https://www.ije.ir/article_70990_7291b5b6e441f06945587b35d4601704.pdf} } @article { author = {Aryanezhad, M.B.}, title = {A Partially Observable Markovian Maintenance Process with Continuous Cost Functions}, journal = {International Journal of Engineering}, volume = {1}, number = {4}, pages = {201-210}, year = {1988}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {In this paper a two-state Markovian maintenance process where the true state is unknown will be considered. The operating cost per period is a continuous random variable which depends on the state of the process. If investigation cost is incurred at the beginning of any period, the system wit I be returned to the "in-control" state instantaneously. This problem is solved using the average criteria. The method involves exploiting the structure of the problem to develop an algorithm which is shown to be more efficient than the usual dynamic programming approach. Results of extensive tests show the accuracy of this algorithm. In addition, it is shown that if certain condition is satisfied, then it is possible to find the average cost per period by a simple calculation.}, keywords = {}, url = {https://www.ije.ir/article_70991.html}, eprint = {https://www.ije.ir/article_70991_915460906a0e128f6aa9d28cb3339baa.pdf} } @article { author = {Mostoufizadeh, A. R. and Molki, Majid}, title = {Average Heat Transfer Coefficient in Rectangular Ducts with Baffle Blockages}, journal = {International Journal of Engineering}, volume = {1}, number = {4}, pages = {211-218}, year = {1988}, publisher = {Materials and Energy Research Center}, issn = {1025-2495}, eissn = {1735-9244}, doi = {}, abstract = {An experimental investigation was conducted to study the average and the fully-developed heat (mass) transfer coefficients in a rectangular smooth duct and a duct with repeated-baffle blockages. The focus of attention in this work is the conventional correlation Nu / Nufd 1 + C / ( X / D ) for the average heat transfer coefficient. It was shown that for relatively short ducts, the coefficient C is not constant but, in general, it depends on the length of the duct. The experiments were carried out via a mass transfer technique and the analogy between heat and mass transfer was employed to predict the heat transfer coefficients. The flow Reynolds number ranged from 3000 to 50,000 with the height of the baffles equal to h/H = 0, 0.125, 0.25 and 0.50.}, keywords = {}, url = {https://www.ije.ir/article_70992.html}, eprint = {https://www.ije.ir/article_70992_6dd0d961f44854f606ab29c183f766ed.pdf} }