Rayleigh surface wave propagation in orthotropic thermoelastic solids under three-phase-lag model

The present article deals with the propagation of Rayleigh surface waves in a homogeneous, orthotropic thermoelastic half-space in the context of three-phase-lag model of thermoelasticity. The frequency equations in closed form are derived and the amplitude ratios of surface displacements and temperature change during the Rayleigh wave propagation on the surface of half-space have been computed analytically. The path of particles during Rayleigh wave propagation is found elliptical and eccentricity of the ellipse is derived. To illustrate the analytical developments, the numerical solution is performed and the computer-simulated results in respect of phase velocity, attenuation coe?cient, and specific loss are presented graphically.     

A chemical synthesized Al-doped PbS nanoparticles hybrid composite for optical and electrical response

Structural, morphological, optical and electrical investigations of pure and Al-doped lead sulfide (PbS) nanoparticles hybrid composite was synthesized by simple chemical route. The detail analysis of the nanoparticle morphology of hybrid composites through optical investigation, phase purity and crystalline size had been characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), ultraviolet spectroscopy (UV), photoluminescence (PL). The lower angle XRD results confirmed that the phase purity and average crystalline size of the pure and Al doped PbS nanoparticles were determined by using the Debye–Scherrer’s formula. The average grain sizes of the pure and the Al-doped PbS nanoparticles were calculated and found to be 22 and 16 nm respectively. Surface morphology analysis was carried out by using SEM and TEM analysis. The surface morphology of pure and Al doped PbS nanoparticles is without any pinholes or cracks and hence they appear to be densely packed with spherical shaped grains. The optical properties of pure and Al-doped PbS analyzed using UV–Vis. absorption spectroscopy and Photoluminiscence (PL) spectra. The band gap values for the pure and the Al-doped PbS nanoparticles were found to be 1.94 and 2.04 eV respectively. The dielectric properties of the Al-doped PbS nanoparticle composites typical response e.g. dielectric constant, dielectric loss, and AC conductivity were analyzed at various frequencies and temperatures.     

AGV scheduling for automated material distribution: a case study

We have studied the scheduling of automated guided vehicles (AGVs) for efficient and uniform material distribution from a truck-dock to machining units of the machine shop in an automotive manufacturing plant. The material distribution problem, being a much simpler special case of the more general material transfer problem, is easily amenable to analysis. We have assessed the number of AGVs required to meet the total material requirements of all the machining units in the shop. Proposing innovative dispatch rules, we have evaluated their performance in simulation by monitoring parameters reflecting efficiency and uniformity of material distribution, both for single AGV and multiple AGV case. In multiple AGV case, we introduce the notion of zones having comparable demands for AGV, and assign one AGV to each zone, so that each AGV can operate largely independently—sharing a minimum path with other AGVs using deadlock avoiding protocols. The results of simulation runs and their implications are discussed.     

Analysis of an unsteady squeezing flow of dusty fluids

The paper considers a theoretical study of the effect on unsteady two-dimensional flow of dusty fluids between two circular plates : one is fixed and the other is in unsteady motion. Using an iterative process, the effect of dust on viscous flow and on variable load capacity has been analysed. The variation of dust concentration due to unsteady motion is also studied. A comparative study of existing results in the steady state with the present results in steady and unsteady states have been made. It is seen that the presence of dust in the flow of fluids not only increases the pressure gradient in the flow but also interacts on viscous behaviour of liquids in the flow, specially in lubrication problems. The paper concludes with a discussion of the effect of vibration of unsteady plate in a squeeze-flow.     

Investigations Using Smooth and Notched Specimens into Validity of Caustic Cracking Susceptibility Diagram

Susceptibility to caustic cracking at different temperatures and caustic concentrations, as predicated by the caustic cracking susceptibility diagram, has been examined by stress corrosion cracking tests using smooth specimens (by slow strain rate testing) and notched specimens (by cylindrical notch tensile testing). Intergranular fracture, as established by scanning electron microscopy, was taken as the confirmatory evidence of caustic cracking. The results generated using notched specimens largely have been consistent with the prediction of the susceptibility diagram.     

Extraction of linear and anomalous features using ERS SAR data over Singhbhum Shear Zone,Jharkhand using fast Fourier transform

Digital filtering of ERS‐2 SAR data using the fast Fourier transform (FFT) has been attempted over Singhbhum shear zone (SSZ) and its surroundings for extraction of linear and anomalous patterns. The results show that numerous lineaments as well as drainage patterns could be identified and demarcated by FFT digital filtering method. Major as well as several minor drainage patterns are easily detectable from the filtered image, which are structurally controlled and not observed in the original map. Comparison of the present interpretation of the study area to existing geological map/earlier interpretation has been done effectively. This technique was found to be more effective in identifying the lineaments using ERS SAR data compared with using Landsat imagery over the study area. The present study reveals that maximum lineaments occurring in the north of SSZ are NNE, NNW and NW trending, while maximum lineaments occurring in the south of SSZ are NE, ENE, WNW, and NW trending. The demarcated geological structures may have a great significance to locate the hidden ore/mineral occurrences. The existences of various mines, such as Baharagora, Mosaboni, Surda, Narwa, Bhatin, Jadugoda, Rakha, and Tatanagar along the shear zone, correlate well with the interpreted results.     

Novel approach to identify good tracer clouds from a sequence of satellite images

A novel hierarchical method for finding tracer clouds from weather satellite images is proposed. From the sequence of cloud images, different features such as mean, standard deviation, busyness, and entropy are extracted. Based on these features, clouds are segmented using the k-means clustering algorithm and considering the coldest cloud segment, potential regions for tracer clouds are identified. These regions are represented by a set of features. All such steps are repeated for images taken at three consecutive time instants. Then, simulated annealing is used to establish an association between cloud segments of successive image frames. In this way, several chains of associated cloud regions are found and are ranked using fuzzy reasoning. The method has been tested in several image sequences, and its results are validated by determining cloud motion vector from the associated chains of tracers.     

The Displacement Perspective During Ultimate Failure of Composite Laminates

This paper deals with the studies on the state of displacement of symmetric and anti-symmetric angle-ply and cross-ply laminated composite plates during its ultimate failure, subjected to transverse static load. First-order shear deformation theory (FSDT) is employed in conjunction with the finite element approach using eight-noded quadratic isoparametric element. The free vibration analyses of isotropic and laminated composite plates are carried out to ensure the overall validity of the present finite element formulation. The mid surface of the laminate is considered as the reference plane. The principal material directions in different laminae are oriented to produce a laminated structural element capable of resisting loads in several directions. The stiffness of a composite laminate is obtained from the properties of the constituent laminae. The affected stiffness of the failed lamina is discarded completely after the failure of weakest ply. The rigidity matrix of the laminate with remaining laminae is re-established. The re-evaluation process continues until the laminate fails completely. To investigate the displacement behaviour of laminates during the ultimate failure, parametric studies are carried out for different cases by varying the stacking sequences, fiber orientations, layer thicknesses, aspect ratios and the number of layers in the laminate. The comparison of results in terms of non-dimensional natural frequencies and ply-by-ply failure analyses obtained from the present investigation are made with those available in the reported literature.     

Carboxymethyl tamarind: Synthesis,characterization and its application as novel drug‐delivery agent

Carboxymethylated tamarind (CMT) has been synthesized by reacting tamarind kernel powder (TKP) with sodium salt of monochloro acetic acid (SMCA) in the presence of sodium hydroxide. This new material was characterized by a variety of materials characterization techniques, namely intrinsic viscosity measurement, FTIR spectroscopy, ¹³C NMR spectra, thermal studies (TGA and DTA), static light scattering (SLS) technique for determination of weight average molecular weight and elemental analysis (C, H, N and O). The material thus developed was studied for its suitability as a matrix for controlled drug delivery. The kinetics of Drug release was also undertaken. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008