The novel equivalent material concept, proposed originally by the author, was utilized together with the mean stress and the point stress failure concepts to predict the load-carrying capacity of O-notched ductile steel plates under pure tension. Unlike for V and U-notches, it was found that the point stress criterion combined with the equivalent material concept could estimate successfully the limited available experimental results reported in literature regarding four O-notched plates made of very ductile steel. By using the model, one may predict well the onset of tensile crack initiation in O-notched ductile components without requiring performing experiments or elastic-plastic analysis.

Semi-submersible drilling platforms are huge bulk structures for extracting the oil products from great depth of seas. For such bulk structures, the Morrison’s equations are no longer valid for determining the loads applied to the semi-submersible drilling platforms. The diffraction theory should be used for evaluating the hydrodynamic interactions between the platform and the sea waves. In this theory, the Laplace equation is solved by considering the boundary conditions of the diffraction theory. In this paper, after a brief description of the diffraction theory, the hydrodynamic interactions between the Iran’s Amirkabir semi-submersible drilling platform and the regular linear waves of Caspian Sea is investigated numerically using boundary element method in the ANSYS/AQWA software. The induced waves exciting forces and moments with different wave heading angles are estimated for six degrees of freedom relative to the waves frequencies using the diffraction theory. The performed hydrodynamic analysis is also validated with the previous works performed for Spar platforms.

Guar gum has seen extensive use in blends, however, its application as a filler in thermoset composites has as yet not been investigated. The effect of the addition of guar gum and its acetyl derivatives on the kinetics of water diffusion in unsaturated polyester composites was studied. The effect of water on the mechanical properties of the composites was studied with respect to the nature of filler, filler concentration and time of immersion. All the mechanical properties were observed to decrease on exposure to water. Further, it was observed that acetylated guar gum, with a degree of substitution of 0.21, showed the best mechanical properties, surpassing the other filled composites and that of the pure unsaturated polyester. Thus, acetylated guar gum showed promise as eco-friendly filler in composite formulation.

In this paper, the stress intensity factors (SIFs) for an interfacial notch in a bi-material joint have been calculated using the experimental method of photoelasticity. A bi-material Brazilian disc specimen with a central interface notch was employed to determine the SIFs for different mode mixities. In this approach, SIFs were calculated experimentally for an Al/Polycarbonate bi-material Brazilian disc specimen and two different loading angles (i.e. modes I and II dominated loading conditions). The results of experimental approach were then compared with the numerical values of finite element method. Experimental results were in good consistency with the numerical values.

Analysis of global electrophilicity and nucleophilicity power of the addends indicate polar character of [2+3] cycloaddition reactions between arylnitrones and trans-substituted nitroethenes. The regioselectivity of these reactions is determined by nucleophilic attack of oxygen atom from nitrone on activated ?-position of nitroalkene. Interaction of this type leads to 4-nitroisoxazolidines, which are the only reaction products.

The coordination complexes of Co(II), Ni(II) and Cu(II) derived from 5-bromosalicylidene-3,4-dimethylaniline (BSMA) and 5-bromosalicylidene-3,4-dichloroaniline (BSCA) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, molar conductance, electronic spectra, 1H-NMR, FAB-mass, ESR, magnetic susceptibility, electrical conductivity and thermal analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand) ratio with coordination number 4 or 6. IR data shows that the ligand coordinates with the metal ions in a bidentate manner through the phenolic oxygen and azomethine nitrogen. FAB-mass and thermal data show degradation pattern of the complexes. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans.

Degradation of integral skin polyurethane foams (ISPUFs) was performed using diethylene glycol (DEG)/-sorbitol/water ternary green solvent system as an effective polyurethane bond destroying agent in combination with basic catalysts, namely sodium and potassium hydroxides, sodium acetate and sodium carbonate. The effects of studied catalysts were investigated and data showed the high performances of sodium hydroxide in recycling process. After completion of the reactions, appeared split phases contained recycled polyols in the upper phase. Reactions were studied using various DEG/-sorbitol/water ratios and the recovered polyols were characterized and data compared with an authentic sample.

The synthesis of Triphenylphosphonium trichloroiodoaluminate (III) ionic liquids (ILs) is reported here. The product was characterized by spectroscopic and analytical methods such as 31P-NMR, FT-IR, cyclic voltammetry, CHN, TGA and differential thermal analysis (DTA). Thermal analyses were used to investigate the thermal behavior of this compound. The results show that this ILs has excellent thermal stability below 110?C. Along with the experimental study; this compound has been studied computationally at the B3LYP/LANL2DZ level of theory using the Gaussian 98 program package. From these calculations, optimized geometries, molecular parameters, and vibrational spectra of ILs have been calculated. In addition, calculated frequencies are compared with the experimental frequencies after correction by the appropriate scaling factor. This comparison shows that our theoretical data are in good agreement with the experimental results.

In today & apos; s world, many planning problems include a hierarchical decision structure with independent and often conflicting objectives. Therefore, the optimization of supply chains with hierarchical structure is essential. In this paper, we investigate a fuzzy multi-objective multi-products supply chain optimization problem in a bi-level structure with one level corresponding to a manufacturer planning problem, while the other to K distribution centers problem. In our model, customer demand and supply chain costs are considered uncertain and will be modeled with use of fuzzy sets. We first describe how different kinds of problems can be modeled as bi-level programming problems. Then, this fuzzy model is first converted into an equivalent crisp model by using ?-cut method in each level, and then by applying extended Kuhn–Tucker approach, we have a linear multi-objective programming problem. Fuzzy goal programming technique is applied to solve the multi-objective linear programming problem to obtain a set of Pareto-optimal solutions. Finally, a numerical example is illustrated to demonstrate the feasibility of the proposed approach.

This paper studies the issue of channel coordination for a decentralized supply chain consisting of one vendor and one buyer in multi-period setting. Considering the allowance of the backorder at the buyer side distinguishes this work in the literature. The credit option contract as an incentive scheme is pursued to encourage the buyer to participate in the coordination model. Order quantity, credit time and backordered demand in each period as decision variables are determined jointly in order to encourage the chain’s member to participate in the coordinating contract. The proposed model shows that the credit option contract for the case of backorder allowance is able to realize the channel coordination in the studied supply chain. A wide range of numerical examples are studied to analyze the sensitivity of the contract efficiency to the inventory system’s parameters such as order cost, holding cost and shortage cost.