An integrated multicriteria model for warranty cost estimation andproduction

Warranty cost estimation for multiple products is considered. The decision variables include the price, warranty time, production quantity, and lot size. System constraints on the above decision variables are based on absolute minimum and maximum values between which those variables should lie. Several goals are considered at different levels of priorities. Some of these goals may be conflicting. The goals considered included operation within a limited resource capacity, the achievement of a specified market share for each product, limitation on the total warranty cost as a given proportion of total sales, limitation of the warranty reserve for a given product as a proportion of the total warranty reserve for all products, and attainment of a minimum level of warranty reserve for a given product as a proportion of the total warranty reserve cost. A goal programming approach is used to solve the formulated problem. An example is illustrated using the proposed formulation, and goal achievements are discussed. Sensitivity analysis is also conducted for some of the model parameters     

TREATMENT OF IRREGULAR GEOMETRIES USING A CARTESIAN COORDINATES FINITE-VOLUME RADIATION HEAT TRANSFER PROCEDURE

Abstract

This article presents a blocked-off-region procedure to model radiative transfer in irregular geometries using a Cartesian coordinates finite-volume method (FVM). Straight-edged, inclined and curved boundaries can be treated. It is capable of handling participating or transparent media enclosed by black or reflecting walls. With this procedure, irregular geometries can be specified through the problem specification portion of the program. Four test problems are used to show that the procedure is capable of reproducing available results for inclined and curved walls, transparent, nonscattering, and anisotropically scattering media.     

APPLICATION OF THE PARTIAL ELIMINATION ALGORITHM FOR SOLVING THE COUPLED ENERGY EQUATIONS IN POROUS MEDIA

This article discusses the solution of coupled energy equations in local thermal nonequilibrium models for porous media. The decoupled solution approach, in which the interaction between the solid and the fluid temperature fields is treated in an explicit manner, converges very slowly when the interface heat transfer coefficient and/or the specific surface area of the porous medium are large (large Biot number). An attractive alternative to the decoupled approach is the partial elimination algorithm, proposed by D. B. Spalding. In this algorithm, the discretization equations are rearranged so that the resulting equations are more implicit and take directly into account the coupling between the two phases. The convergence rates of these two solution procedures are studied with reference to convective heat transfer in a two-dimensional channel filled with a porous medium. The partial elimination algorithm converges much more quickly than the decoupled procedure, with the number of iterations required for convergence becoming constant for large Biot numbers.     

Involvement of selectin-like carbohydrate binding specificity in human gamete interaction

The recognition of carbohydrate epitopes by complimentary protein receptors has been shown to be a critical factor in gamete interaction in many different animal species. In this study it was hypothesized that, in the human, gamete binding requires an interaction between selectin ligands on the zona pellucida and putative egg binding proteins on the sperm surface. The hemizona assay (a unique internally controlled bioassay that evaluates tight binding of sperm to the zona) and advanced methods of carbohydrate analysis were used to test this hypothesis. From these tests it was shown that oligosaccharide recognition is also required for initial human gamete binding. This study suggests the existence of distinct egg binding proteins on human sperm that can bind to selectin ligands. Additionally, the results suggest a possible convergence in the types of carbohydrate sequences recognized during initial human gamete binding and immune/inflammatory cell interactions. Glycoconjugates that manifest selectin-ligand activity and that express specific carbohydrate epitopes have potent contraceptive and immunosuppressive effects. Such specific oligosaccharide sequences may provide an appropriate recognition signal for embryo development and protection.     

Water sharing between India and Pakistan: a critical evaluation of the Indus Water Treaty

For nearly 50 years a relatively stable Indus Water Treaty (IWT) moderated competition for the Indus water between Pakistan and India. Rising demand for water in each nation could unsettle this stable relationship, as foreshadowed by the involvement of a third party during 2005–2007 for the first time in the treaty's history. This paper discusses Pakistan and India's experience in the context of other international shared rivers. For the benefit of their people, Pakistan and India could coordinate unilateral development and resolve issues rather than defer them.     

Structural, dielectric and transport properties of Pb(Mno.5Wo.5)O3

Polycrystalline Pb(Mn_0.5W_0.5)O₃, a ferroelectric oxide having perovskite structure, was prepared by high temperature solid state reaction technique. Preliminary X-ray diffraction analysis confirms single phase formation with the lattice parametersa = 7.2501 Å,b = 8.1276 Å andc = 12.0232 Å. Room temperature dielectric constant (ε′) and loss tangent (tan δ) were scanned with respect to frequency in the range 100 Hz-1 MHz. Detailed study of dielectric constant and electrical conductivity reveals a phase change around 400 K, which is quite different from those in the other materials of the same type. Further, the seebeck coefficient (α) is temperature independent. The conduction is interpreted as due to small polaron hopping.