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Nowadays, the Nd:YAG laser has been a promising key tool for joining thin components. In this research, mechanical and microstructural properties of laser welded thin austenitic stainless steel sheets were investigated with experimental investigations, as a function of laser welding parameters. Butt welded joints were made using a Nd:YAG laser in the pulsed wave mode. The appropriate laser welding parameters were found in order to obtain quality and strong weld seam. The pulsed laser seam welding process is controlled by a variety of parameters. We focus on the effects of the several processing parameters on mechanical and microstructural characteristics of joint and weld quality. The aim of this research was to evaluate the influence of these processing parameters on joint strength and microstructure. And also we examined the weldability of stainless steels in butt joint configuration by a pulsed Nd:YAG laser beam.

A new vicinal dioxiroe ligand with two 2-benzimidazolylmethyl groups, namely S,S'-bis(2-benzimidazolylroethyl)dithioglyoxime (H2L), has been prepared from cyanogen-di-N-oxide and 2-mercaptomethylbenz-imidazole in dichloromethane at -10°C. Nickel(II), palladium(II), cobalt(II) and cobalt(III) complexes of H2L have a metal : ligand ratio of 1 : 2 and the ligand coordinates through the two N atoms, as most of the vicinal dioximes. [Co(HL)2(L')Cl] has been prepared with L' = pyridine, 2,6-dimethylpyridine, 2-mercaptopyridine, 2-car-boxypyridine, pyridine-2-carboxyaldehyde, triphenylphosphine, tri-phenylarsine, together with a chloride ion as axial ligands. All these complexes are slightly soluble in common organic solvents. Structures are proposed according to elemental analyses, 1H, 13C-NMR IR, and UV-Visible spectral data.

This paper describes an upper bound technique for the evaluation of the shakedown limit of thin cyclindrical shells subject to thermal loading. The method is based upon the upper bound kinematic shakedown theorem of Koiter. By suitable choice of displacement field, in a finite element form, and yield surface, the problem is reduced to a linear programming problem. A number of solutions are presented involving a tube subjected to a moving temperature front which indicates that the technique provides, in an efficient way, a complete description of the load levels at which ratchetting would occur and the corresponding modes of deformation. The technique seems therefore, to provide a useful intermediary between the use of the simple rules incorporated in design codes and full inelastic analysis.

People with impaired glucose tolerance are considered to be prone to diabetes. To evaluate their visual function we investigated colour vision with the Farnsworth-Munsell 100 Hue test and contrast sensitivity with Arden's grating cards in people with impaired glucose tolerance (IGT), people with normal glucose tolerance (NGT) and others with type II diabetes (NIDDM). Eyes with low vision or any anterior or posterior segment abnormalities were excluded. Contrast sensitivity and color vision differed significantly between the groups (p<0.01). It thus appears that patients with IGT but without clinical diabetes could be followed up to see whether these alterations have any predictive value for the development of diabetes and diabetic retinopathy.

The paper discusses the relationship between material properties and structural ratcheting for thin cylindrical shells subjected to severe thermal loading. The need to understand this problem arises in the design of Sodium Cooled Fast Reactors. A sequence of shakedown solutions are presented using a finite element technique [13]. It is shown that for tubes subject to moving temperature fields, ratcheting can occur even when no mechanical loads are applied and the material strongly cyclically hardens. Only small movements are required. Stationary thermal cycling is less likely to produce ratcheting. The calculations are compared with two sets of experimental data, which serve to confirm these conclusions.

In an accompanying paper an extended shakedown theory was described for structures subjected to constant mechanical loads and cyclically varying thermal loads, a circumstance of interest in Fast Reactor design. In this paper the upper bound theorem is used to construct interactive diagrams for a sequence of sample problems. These examples imply that for many shell problems, where the temperature variations occur along the surface, ratchetting occurs in two distinct ways. For low thermal loading the structure deforms in the same mechanism that occurs at plastic collapse when only the mechanical loads are applied. For high levels of thermal loading the mechanism changes to a local concentration of strain. This behavior differs significantly from that of the Bree problem. In one example this mechanism involves through-thickness shear deformation of a plate; as a consequence the use of thin shell theory which ignores shear deformation in numerical solutions of problems of this type is likely to result in nonconservative estimates of inelastic deformations.

The paper describes an extension of classical shakedown theory for structural problems involving constant mechanical loads and cyclic variations in temperature. The objective of the theory is to provide a simple means of distinguishing between circumstances where thermal cycling can cause structural ratchetting for small or zero mechanical loads from those where very substantial thermal stresses can occur with no danger of ratchetting. This distinction is of particular importance in the design of Liquid Metal Fast Breeder Reactors and current design codes do not address this problem directly. An extended definition of material shakedown is described that provides a conservative theory, taking into account cyclic strain hardening. Some simple experiments on a two-bar structure demonstrates the relevance of the theory to observed structural behavior.

A simple wet-chemical synthesis method was developed to fabricate Zinc oxide micro-rod clusters. The synthesis process involved the rapid dilution of a zinc-bearing alkaline solution at 150°C in a convection oven on indium tin oxide (ITO) substrates. The synthesis was carried out by immersing an unseeded ITO substrate in a mixture of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and hexamethylenetetramine ((CH2)6N4) aqueous solution. The obtained sample was annealed at 400°C for 2 h. The structural, morphological and optical properties of the synthesized ZnO microstructures were investigated by X-ray diffraction, scanning electron microscopy and ultraviolet-visible spectroscopy, respectively. The ZnO rod clusters are hexagonal phase of the wurtzite structure. The crystal grain sizes of the films were found to be 72.6, 84.3 and 66.3 nm for the (100), (002) and (101) crystal planes, respectively. The optical bandgap of the ZnO was determined to be 3.147 eV.