Development of a numerical methodology for analysis and design of weldments

There are many analysis formulas for determining the resultant shear force in welds. However, there is no general procedure which is applicable to a joint with all six possible loadings exerted simultaneously. A numerical methodology and computer program for such a problem were developed, and they are capable of analyzing a weld of any shape composed of straight or circular line segments. The computer program developed in this study can also display the design procedures and results using computer graphics. The development of such a design procedure and an interactive computer program for weldments analysis will lead to lower cost.     

Specification of retinogeniculate X and Y axon arbors in cats: fundamental differences in developmental programs

Solitary osteochondromas are usually of little significance. However, if they are located near neurologic structures, they may cause irritation due to compression. Spinal cord compression is a rare but potentially catastrophic manifestation of solitary osteochondromas. As far as can be ascertained, a solitary osteochondroma in the lumbar region with spinal cord compression has not been reported in Taiwan. This article includes the treatment of an 11-year-old girl with osteochondromas which was complicated by the late development of kyphoscoliosis and a review of the literature.     

bcl-2, p53 immunophenotypes and apoptosis in squamous cell carcinoma of the oesophagus

To establish baseline information on neopterin concentrations in livestock, companion and laboratory animals and identify the factors that may influence these concentrations, blood samples were taken from normal dairy cattle, horses, llamas, dogs, cats and rats of varying ages and sexes. In addition, neopterin concentrations in normal, adult equines were compared with those found in racing Thoroughbreds. There were no differences due to sex, sexual maturity, pregnancy, castration, or age. For all ages and sexes combined, mean neopterin concentrations were significantly lower in llamas (2.27+/-0.33 nmol litre(-1)) and rats (2.13+/-0.21 nmol litre(-1)) when compared with the other species tested. Racing Thoroughbreds demonstrated higher neopterin values than adult equines not in training (3.54+/-0.64 vs 3.13+/-1.02 nmol litre(-1)).     

Reliability evaluation of k-out-of-n redundant system with partially energized stand-by units

A new probabilistic model representing an “n” units non-repairable system with “k” units operating and (n − k) units kept in stand-by mode (as partially energized) is represented in this paper. Human error, common cause and switching system failure are also considered in this modelling. The mathematical expression for state probabilities, reliability, mean time to failure and variance of time to failure is formulated. Numerical results are also presented to demonstrate the effect on unreliability and mean time to failure due to variation of redundancy in stand-by mode.     

Topological properties of star graphs

Our purpose in the present paper is to investigate different topological properties of the recently introduced star graphs which are being viewed as attractive alternatives to n-cubes or hypercubes. These properties are interesting by themselves from a graph theory point of view as well as they have direct in generating vertex disjoint paths and minimal paths in a star graph. They can also be readily utilized to design routing algorithms and to compute contention and traffic congestion in networks that use star graphs as the underlying topology.     

A study on mechanical and microstructure characteristics of the STS304L butt joints using hybrid CO2 laser-gas metal arc welding

In order to examine mechanical characteristics of the stainless steel (STS304L) hybrid welded butt joints, two-dimensional thermal elasto-plastic analysis has been carried out. To this end, a 2D simulation model has been developed considering hybrid welding features. Based on thermal history data obtained from this heat source model, the residual stress distribution in weld metal (WM), heat affected zone (HAZ) and base metal (BM) characteristics have been calculated and found to be in reasonable agreement with the experimentally measured values. In order to investigate the effect of welding process, thermal elasto-plastic behaviour of the hybrid welded joints was compared with a welded joints obtained by conventional submerged arc welding (SAW) process. The results show that the longitudinal residual stress in the hybrid welded joints is less (13–15%) than that of the SA welded joints. Weld metal formed in both welding processes shows very fine dendritic structure. Due to higher heat input in SAW, the HAZ size of the SA welded joints is more than twice that of the hybrid welded joints. Therefore, from mechanical and metallurgical point of view, it could be confirmed that it makes a good sense to use SAW instead of hybrid CO₂ laser-gas metal arc welding (GMAW) for butt joint of the STS304L thick steel.     

A generalized thermoelastic problem due to nonlocal effect in presence of mode I crack

Abstract

This article constructs a new model of nonlocal thermoelasticity which resolves a dynamical problem of a homogeneous, isotropic infinite space weakened by a finite linear mode I crack. The boundary of the crack is being subjected to a prescribed temperature distribution and stress. In the context of three-phase lag model of generalized thermoelasticity, the governing equations have been solved employing the Laplace and the Fourier transforms, which reduces to four dual integral equations, the solution of which is equivalent to solving the Fredholm’s integral equation of the first kind. These integral equations have been solved employing the Maple software package, while the numerical inversion of the Laplace transform is carried out with the help of Bellman method. Numerical computations for a copper material are performed and demonstrated graphically. The results provide a motivation to further investigate the problem and draw concluding remarks due to the influence of nonlocality also.     

A Privacy-Preserving Location Assurance Protocol for Location-Aware Services in VANETs

A location-aware service on a vehicular ad hoc networks (VANETs) is to provide services that distribute on-demand information for a certain geographic area of interest by taking advantage of vehicular communications. In this paper, we propose a secure and location assurance protocol in order to guarantee privacy preservation in vehicular communications and trustworthiness of location-aware services over VANETs. The proposed protocol enables a message verifier to have confidence that the location-aware information was responded from the vehicles passing through the target location area of interest without violating location privacy of the responders. To achieve our security objectives, we consider a pseudonym-based privacy-preserving authentication and a hierarchical identity-based cryptographic scheme. Furthermore, we demonstrate experimental results to confirm the efficiency and effectiveness of the proposed protocol.     

A novel wideband Minkowski fractal antenna with assistance of triangular dielectric resonator elements

This article concentrates on the design and analysis of a novel Minkowski fractal‐based antenna design with the aid of triangular dielectric resonator (TDR) elements for wideband wireless applications. mode is excited inside equilateral TDR antenna with the help of coaxial probe feed. Wide impedance bandwidth has been achieved by reducing the quality factor with the help of increasing surface area‐to‐volume ratio of radiating structure. Another important feature of this article is that recurrence formulas are derived to calculate the fraction of surface area to volume of proposed fractal antenna up to nth iteration. The proposed antenna design is fabricated and measured up to third iteration to verify its simulated outcomes. Practically measured outcome confirms that the proposed antenna design operates over the frequency range, that is, 2.23‐3.1 GHz with the maximum gain of 3.62 dBi. These features make it appropriate for wireless LAN (2.4 GHz) and WiMAX (2.5 GHz) applications.