M.A. Rabah, S.M. Eldighidy and A.A. Aboukhashaba
The specific influence of calcium and sodium cations on the rate of deposition of a‐Fe2O3 (a main corrosion product in boilers and heat exchangers) has been experimentally…
Abstract
The specific influence of calcium and sodium cations on the rate of deposition of a‐Fe2O3 (a main corrosion product in boilers and heat exchangers) has been experimentally studied. A deposition model based on the microlayer evaporation and dryout phenomena that occur in the nucleate boiling bubble is put forward for interpretation of the deposited layer. It has been found that the rate of deposition of Fe2O3 increases with the increase in valency of the soluble cations. With calcium, the deposition rate increases linearly with the increase in its ionic concentration, whereby the rate is increased by 5.9, 6.8 and 7.6 with 200, 400 and 600 ppm calcium respectively. Development of the deposition layer takes place in the valleys of the surface contour according to a micro‐layer evaporation mechanism. Successive deposition is performed at the periphery of the first deposit. Reduction in cation content in the crude solution and selecting smooth heated surfaces are recommended to reduce the ∝‐Fe2O3 deposition on heated surfaces in boiling water.
M.A. Rabah, S.M. Eldighidy and A.A. Aboukhashaba
Ball‐point ink is a heterogeneous, viscous multi‐phase fluid. It consists of resins, solvents, diluents together with solid pigment and filler. The fluid is contained in a thin…
Abstract
Ball‐point ink is a heterogeneous, viscous multi‐phase fluid. It consists of resins, solvents, diluents together with solid pigment and filler. The fluid is contained in a thin polyethylene tube which acts as a fluid reservoir continuously supplying the ink to a narrower brass tube. The latter has an inner diameter of about 0.8 mm and holds a small ball at its tip. During storage for long periods, agglutination of the ink takes place in the brass tube and around the ball as well. The rate of such agglutination is strongly related to the environmental conditions. In the present work, a technique is developed to measure the thickness of the agglutinated ink film by means of a microscopic examination. Hence the thickness of the deposited solid layer on the internal periphery of the brass tube will be estimated. Furthermore, factors affecting the agglutination process will be investigated and methods to decrease or even to eliminate that phenomenon will be put forward.
Tankfreight Ltd., of Harrogate, part of the employee‐owned National Freight Consortium, has been awarded a major contract by Vinyl Products on the basis of their ability to offer…
Abstract
Tankfreight Ltd., of Harrogate, part of the employee‐owned National Freight Consortium, has been awarded a major contract by Vinyl Products on the basis of their ability to offer an extremely economical all‐round package.