Optical read-out scheme based on Grated Waveguide Cantilever cavity resonance for interrogation of cantilever sensor arrays

The design and analysis of an optical read-out scheme based on a grated waveguide (GWG) resonator for interrogating microcantilever sensor arrays is presented. The optical system consisting of a micro cantilever monolithically integrated in proximity to a grated waveguide (GWG), is realized in silicon optical bench platform. The mathematical analysis of the optical system is performed using a Fabry-Perot interferometer model with a lossy cavity formed between the cantilever and the GWG and an analytical expression is derived for the optical power transmission as a function of the cantilever deflection which corresponds to cavity width variation. The intensity transmission of the optical system for different cantilever deflections estimated using the analytical expression captures the essential features exhibited by a FDTD numerical model.

Efficient Cache Exploration Method for a Tiled Chip Multiprocessor

Past studies use deterministic models to evaluate optimal cache configuration or to explore its design space. However, with the increasing number of components present on a chip multiprocessor (CMP), deterministic approaches do not scale well. Hence, we apply probabilistic genetic algorithms (GA) to determine a near-optimal cache configuration for a sixteen tiled CMP. We propose and implement a faster trace based approach to estimate fitness of a chromosome. It shows up-to 218x simulation speedup over the cycle-accurate architectural simulation. Our methodology can be applied to solve other cache optimization problems such as design space exploration of cache and its partitioning among applications/ virtual machines.

Modified particle swarm optimization for pattern clustering

Data clustering is a common technique for statistical data analysis, which is used in many fields, including machine learning and data mining. Clustering is grouping of a data set or more precisely, the partitioning of a data set into subsets (clusters), so that the data in each subset (ideally) share some common trait according to some defined distance measure. In this paper we present the genetically improved version of particle swarm optimization algorithm which is a population based heuristic search technique derived from the analysis of the particle swarm intelligence and the concepts of genetic algorithms (GA). The algorithm combines the concepts of PSO such as velocity and position update rules together with the concepts of GA such as selection, crossover and mutation. The performance of the above proposed algorithm is evaluated using some benchmark datasets from Machine Learning Repository. The performance of our method is better than k-means and PSO algorithm.

Effect of equal channel angular pressing on grain refinement and texture evolution in a biomedical alloy Ti-13Nb-13Zr

Evolution of texture and concomitant grain refinement during Equal Channel Angular Pressing (ECAP) of Ti - 13Nb - 13Zr alloy has been presented. Sub-micron sized equiaxed grains with narrow grain size distribution could be achieved after eight pass at 873 K. A characteristic ECAP texture evolved in alpha phase till four passes while the evolution of characteristic ECAP texture in the beta phase could be observed only beyond the fourth pass. On increasing the deformation up to eight passes, the texture in alpha phase weakens while the beta phase shows an ideal ECAP texture. A weaker texture, low dislocation density and high crystallite size values in alpha phase suggest the occurrence of dynamic recrystallization. The absence of texture evolution in beta phase till four passes can be attributed to local lattice rotations. The characteristic ECAP texture in the eight pass deformed sample is attributed to delayed dynamic recrystallization in the beta phase. (C) 2013 Elsevier Inc. All rights reserved.

Effect of FIB milling on MEMS SOI cantilevers

Stress induced by Focused Ion Beam (FIB) milling of cantilevers fabricated on silicon-on-insulator (SOI) wafer has been studied. Milling induces stress gradients ranging from -10MPa/μm to -120MPa/μm, depending on the location of cantilevers from the point of milling. Simulations were done to estimate the stress in the milled cantilevers.

Role of melt convection on optimization of PCM-based heat sink under cyclic heat load

In this article, we study the thermal performance of phase-change material (PCM)-based heat sinks under cyclic heat load and subjected to melt convection. Plate fin type heat sinks made of aluminum and filled with PCM are considered in this study. The heat sink is heated from the bottom. For a prescribed value of heat flux, design of such a heat sink can be optimized with respect to its geometry, with the objective of minimizing the temperature rise during heating and ensuring complete solidification of PCM at the end of the cooling period for a given cycle. For given length and base plate thickness of a heat sink, a genetic algorithm (GA)-based optimization is carried out with respect to geometrical variables such as fin thickness, fin height, and the number of fins. The thermal performance of the heat sink for a given set of parameters is evaluated using an enthalpy-based heat transfer model, which provides the necessary data for the optimization algorithm. The effect of melt convection is studied by taking two cases, one without melt convection (conduction regime) and the other with convection. The results show that melt convection alters the results of geometrical optimization.

Electric current induced flow of liquid metals: Mechanism and substrate-surface effects

Long range, continuous flow of liquid metals occurs upon application of an electric current. Here, we report experimental results elucidating the mechanism of current-induced liquid metal flow, and its dependence on substrate surface condition. It is shown that the observed flow is diffusion-controlled, with the flow-rate depending linearly on applied current density, indicating that it is driven by electromigration. The effective charge number for liquid electromigration, Z*, of several pure metals, such as Al, Bi, Ga, Sn, and Pb, were deduced from the experimental results and were found to be close to the elemental valency. With the exception of liquid Pb, Z* for all liquid metals tested in this study were positive, indicating that: (i) electron wind contributes much less to Z* in liquid metals than in solids, and (ii) with a few exceptions, liquid metals generally flow in the direction of the electric current. On smooth substrates which are wetted well by the liquid metal, flow occurs in a thin, continuous stream. On rough surfaces which are poorly wetted, on the other hand, discrete beads of liquid form, with mass transport between adjacent beads occurring by surface diffusion on the substrate. A rationale for the role of substrate roughness in fostering this observed transition in flow mechanism is presented. (C) 2014 AIP Publishing LLC.

A composition-dependent ``re-entrant'' crystallographic phase transition in the substitutional metal acetylacetonate complex (Cr1-xGax)(acac)(3)

The formation of a complete solid solution between acetylacetonate (acac) complexes of chromium and gallium, (Cr1-x,Ga-x)(acac)(3) for 0.1 gated through the co-synthesis method. Wellcrystallised, subliming solids are found to form for each nominal value of x, with thermal analysis confirming each composition to have a congruent melting point, making it a substitutional complex. Whereas the pure complexes (i.e. the end members of the solid solution, x = 0 and x = 1) are both centro-symmetric, a composition-dependent crystallographic phase transition to a non-centrosymmetric structure is found to occur for compositions with 0.4 < x < 0.9. Such a ``re-entrant'' crystallographic transition is interpreted to be due to the drive to overcome the disorder present in certain centrosymmetric chromium-rich compositions, by going over to a non-centrosymmetric structure with a doubling of the unit cell. The substitutional complex is shown to lead to a substitutional oxide with the beta-gallate structure. (C) 2014 Elsevier Ltd. All rights reserved.

A Dinuclear Cadmium(II) Schiff Base Thiocyanato Complex: Crystal Structure and Fluorescence

A new dinuclear cadmium(II) complex, Cd(L)(NCS)](2) (1) has been synthesized using a potentially tetradentate Schiff base ligand HL, 2-((E)-(2-(diethylamino) ethylimino) methyl)-6-methoxyphenol, obtained by the condensation of 2-diethylaminoethylamine and o-vanillin, and characterized by different physicochemical techniques. Crystal structure of the title complex was unambiguously established by single crystal X-ray diffraction which reveals that metal centers are connected by bridging phenolato and chelating methoxy oxygen atoms of the coordinating Schiff bases and embedded in severely distorted octahedral geometries. Fluorescence properties of the ligand and its complex, studied at room temperature indicate that later may serve as strong fluorescent

Accurate point matching based on multi-objective Genetic Algorithm for multi-sensor satellite imagery

This paper investigates a novel approach for point matching of multi-sensor satellite imagery. The feature (corner) points extracted using an improved version of the Harris Corner Detector (HCD) is matched using multi-objective optimization based on a Genetic Algorithm (GA). An objective switching approach to optimization that incorporates an angle criterion, distance condition and point matching condition in the multi-objective fitness function is applied to match corresponding corner-points between the reference image and the sensed image. The matched points obtained in this way are used to align the sensed image with a reference image by applying an affine transformation. From the results obtained, the performance of the image registration is evaluated and compared with existing methods, namely Nearest Neighbor-Random SAmple Consensus (NN-Ran-SAC) and multi-objective Discrete Particle Swarm Optimization (DPSO). From the performed experiments it can be concluded that the proposed approach is an accurate method for registration of multi-sensor satellite imagery. (C) 2014 Elsevier Inc. All rights reserved.