A theoretical study is presented in this paper to investigate the conjugate heat transfer across a vertical finite wall separating two forced and free convection flows at different temperatures. The heat conduction in the wall is in the transversal direction and countercurrent boundary layers are formed on the both sides of the wall. The governing equations of this problem and their corresponding boundary conditions are all cast into a dimensionless form by using a non-similarity transformation.These resultant equations with multiple singular points are solved numerically using a very efficient singular perturbation method. The effects of the resistance parameters and Prandtl numbers on heat transfer characteristics are investigated. INTRODUCTIONThe study of thermal interaction between two semi-infinite fluid reservoirs at different temperatures through a vertical conductive wall is a very important topic in heat transfer because of its numerous engineering applications. This heat transfer process applies to reactor cooling, heat exchangers, thermal insulation, nuclear reactor safety, etc. Additionally, such interaction mechanism is, for the most part, inherent in the design of heat transfer apparatus. On the other hand, it is worth mentioning that demands in heat transfer engineering have requested researchers to develop the new types of equipments with superior performances, especially compact and lightweight ones. The need for small-size units requires detailed studies on the effects of interaction between the thermal field in both fluids and the wall conduction, which usually degrades the heat exchanger performance.

A comprehensive review of current analytical models, experimental techniques, and influencing factors is carried out to highlight the current challenges in this area. The study of fluid-solid boundary conditions has been ongoing for more than a century, starting from gas-solid interfaces and progressing to that of the more complex liquidsolid case. Breakthroughs have been made on the theoretical and experimental fronts but the mechanism behind the phenomena remains a puzzle. This paper provides a review of the theoretical models, and numerical and experimental investigations that have been carried out till date. Probable mechanisms and factors that affect the interfacial discontinuity are also documented.

A comprehensive study of the problem of laminar film condensation with both a gravitational type body force and a moving vapour concurrent and parallel to the surface has been presented here. It demonstrates where both the body force and vapour velocity are significant through a comprehensive numerical solution obtained by a modified Keller box method. Important parameters governing condensation and heat transfer of pure vapour are determined. A perturbation analysis is applied in the leading edge and downstream regimes. The thin film approximations for the both regimes are obtained and compared with exact numerical solutions. INTRODUCTIONThe problem of laminar film condensation on a vertical plate with both a gravitational type body force and a moving vapour concurrent and parallel to the surface is not only of theoretical interest but also of great practical importance in a number of technological processes. There have been sporadic publications in the area of the laminar body-force-only film condensation problem and in the area of the laminar forced convection film condensation problem.In the area of the laminar body-force-only film condensation, the pioneer work was reported by Nusselt (1916), who formulated this problem in terms of simple force and heat balances within the condensate film. The effects of inertia forces, energy convection and vapour drag were not taken into account. In the area of the laminar forced convection film condensation, Jacobs (1966) assumed that the inertia terms of the liquid film have negligible effect and that the temperature distribution across the film is linear. Beckett and Poots (1972) using boundary-layer similarity techniques presented a comprehensive solution to this problem without a body force.In the present investigation, a comprehensive theoretical model for the problem of combined body force and forced convection laminar film condensation has been built up. Accordingly the heat transfer and condensation rates in this problem have accurately been predicted by employing perturbation techniques and exact numerical results which have been computed by using the continuous transformation computation (Hunt and Wilks 1981) and the modified Box scheme (Shu and Wilks 1995).

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Degeneracy is a salient feature of genetic codes, because there are more codons than amino acids. The conventional table for genetic codes suffers from an inability of illustrating a symmetrical nature among genetic base codes. In fact, because the conventional wisdom avoids the question, there is little agreement as to whether the symmetrical nature actually even exists. A better understanding of symmetry and an appreciation for its essential role in the genetic code formation can improve our understanding of nature's coding processes. Thus, it is worth formulating a new integrated symmetrical table for genetic codes, which is presented in this paper. It could be very useful to understand the Nobel laureate Crick's wobble hypothesishow one transfer ribonucleic acid can recognize two or more synonymous codons, which is an unsolved fundamental question in biological science.