Secret Image Communication Scheme Based on Visual Cryptography and Tetrolet Tiling Patterns

Visual cryptographic scheme is specially designed for secret image sharing in the form of shadow images. The basic idea of visual cryptography is to construct two or more secret shares from the original image in the form of chaotic image. In this paper, a novel secret image communication scheme based on visual cryptography and Tetrolet tiling patterns is proposed. The proposed image communication scheme will break the secret image into more shadow images based on the Tetrolet tiling patterns. The secret image is divided into 4×4 blocks of tetrominoes and employs the concept of visual cryptography to hide the secret image. The main feature of the proposed scheme is the selection of random blocks to apply the tetrolet tilling patterns from the fundamental tetrolet pattern board. Single procedure is used to perform both tetrolet transform and the scheme of visual cryptography. Finally, the experimental results showcase the proposed scheme is an extraordinary approach to transfer the secret image and reconstruct the secret image with high visual quality in the receiver end.     

Luminescence in Porous Silicon—Surface vs. Bulk

The mechanism of luminescence in porous silicon still remains poorly understood. The main point of controversy is whether the luminescence is due to recombination in the quantum size structures that constitute porous silicon or whether it is dominated by surface recombination. In this paper, we present evidence that emphasises the role that surface recombination plays in the luminescence of porous silicon. In this framework, we also attempt to reconcile the resonant luminescence data (which argues for bulk recombination) with our results.     

Kinetic analysis of NO-sensitized methane oxidation

The role of NO-sensitized oxidation during the product-gas entrainment of a low-NO_x, multi-jet, natural gas burner is investigated. A detailed kinetic mechanism for the NO-sensitized oxidation of CH₄, consisting of 483 reactions and 69 species, is used for the kinetic analysis. An eigenvalue-eigenvector decomposition is performed on normalized sensitivity coefficients to study the important reactions using principal component analysis (PCA), and the loadings corresponding to the largest eigenvalue are used to identify the reaction pathways of NO-sensitized oxidation. The main reaction pathway is most strongly affected by the temperature profile and equivalence ratio. Also, a reduced kinetic scheme of 110 reactions and 47 species is developed by eliminating reactions with small loadings. The temporal evolution of reactions is investigated using functional PCA, in which the functional loadings reflect the importance of reactions as a function of time. A discretization approach is used to perform the functional PCA.     

On-Line Learning Failure-Tolerant Neural-Aided Controller for Earthquake Excited Structures

This paper presents an on-line learning failure-tolerant neural controller capable of controlling buildings subjected to severe earthquake ground motions. In the proposed scheme the neural controller aids a conventional H∞ controller designed to reduce the response of buildings under earthquake excitations. The conventional H∞ controller is designed to reduce the structural responses for a suite of severe earthquake excitations using specially designed frequency domain weighting filters. The neural controller uses a sequential learning radial basis function neural network architecture called extended minimal resource allocating network. The parameters of the neural network are adapted on-line with no off-line training. The performance of the proposed neural-aided controller is illustrated using simulation studies for a two degree of freedom structure equipped with one actuator on each floor. Results are presented for the cases of no failure and failure of the actuator on each of the two floors under several earthquake excitations. The study indicates that the performance of the proposed neural-aided controller is superior to that of the H∞ controller under no actuator failure conditions. In the presence of actuator failures, the performance of the primary H∞ controller degrades considerably, since actuator failures have not been considered for the design. Under these circumstances, the neural-aided controller is capable of controlling the acceleration and displacement structural responses. In many cases, using the neural-aided controller, the response magnitudes under failure conditions are comparable to the performance of the H∞ controller under no-failure conditions.     

Novel microporous carbon material with flower like structure templated by MCM-22

Novel flower like microporous carbons with very high surface area have been synthesized for the first time using MCM-22 zeolite as a template and sucrose as a carbon source. The textural parameters of the materials can easily be tuned by the simple adjustment of the sucrose to MCM-22 weight ratio. It has been also found that the specific surface area of the microporous carbon materials is much higher as compared with that of its parent zeolite template.     

Enhancement of high-temperature high-frequency performance ofGaAs-based FETs by the high-temperature electronic technique

This paper reports the effects of high temperature on high-frequency/high-speed field effect transistors (FETs), particularly GaAs-based MESFETs and HEMTs. The high-temperature electronic technique (HTET) was employed to stabilize and improve the performance of these devices at high temperatures. This work focuses on detailed high-temperature experiments of high-frequency scattering parameters of various transistors. Comparable gain level to that obtained at room temperature was achieved at elevated temperature through the use of the HTET     

Preparation and Characterization of Ni-Ferrite Coating on Carbon Steel Coupons

1.IntroductionTheinteractionofhightemperaturewaterwithcarbonsteel(CS)structuralsurfacesundertheprimaryheattransport(PHT)chemistryconditionsresultsintheformationofaprotectivemagnetitefilmwhichhasabilayerstructure.TheoxidelayerclosetometalgrowsintoitduetoO2-movementandoxi-dationofiron.Theouterlayerisformedbyprecipita-tionofFe3O4duetosupersaturationofthecirculat-ingcoolallt.Therelativemagnitudeofthethicknessofthetwolayersandtheirvariationwithtimeareaffectedbymanyfactors.Theporosityofthefilmgi…     

Probing and repairing damaged surfaces with nanoparticle-containing microcapsules

Nanoparticles have useful properties, but it is often important that they only start working after they are placed in a desired location. The encapsulation of nanoparticles allows their function to be preserved until they are released at a specific time or location, and this has been exploited in the development of self-healing materials and in applications such as drug delivery. Encapsulation has also been used to stabilize and control the release of substances, including flavours, fragrances and pesticides. We recently proposed a new technique for the repair of surfaces called 'repair-and-go'. In this approach, a flexible microcapsule filled with a solution of nanoparticles rolls across a surface that has been damaged, stopping to repair any defects it encounters by releasing nanoparticles into them, then moving on to the next defect. Here, we experimentally demonstrate the repair-and-go approach using droplets of oil that are stabilized with a polymer surfactant and contain CdSe nanoparticles. We show that these microcapsules can find the cracks on a surface and selectively deliver the nanoparticle contents into the crack, before moving on to find the next crack. Although the microcapsules are too large to enter the cracks, their flexible walls allow them to probe and adhere temporarily to the interior of the cracks. The release of nanoparticles is made possible by the thin microcapsule wall (comparable to the diameter of the nanoparticles) and by the favourable (hydrophobic-hydrophobic) interactions between the nanoparticle and the cracked surface.     

Numerical simulations of crack tip fields in polycrystalline plastic solids

In this paper, modes I and II crack tip fields in polycrystalline plastic solids are studied under plane strain, small scale yielding conditions. Two different initial textures of an Al-Mg alloy, viz., continuous cast AA5754 sheets in the recrystallized and cold rolled conditions, are considered. The former is nearly-isotropic, while the latter displays distinct anisotropy. Finite element simulations are performed by employing crystal plasticity constitutive equations along with a Taylor-type homogenization as well as by using the Hill quadratic yield theory. It is found that significant texture evolution occurs close to the notch tip which profoundly influences the stress and plastic strain distributions. Also, the cold rolling texture gives rise to higher magnitude of plastic strain near the tip.     

Information system utilization in supply chain integration efforts

This paper investigates a set of advisable strategies for information systems utilization in supply chain integration initiatives. Through an analysis of structural relationships among the ways in which information systems are utilized for supply chain integration--i.e. Infrastructural Support, Value Creation Management, Logistical Operations--and supply chain management performance, we argue that there might be a recommended sequence in using information systems for supply chain integration. Tests of hypotheses relating to information systems utilization using empirical data from manufacturing firms indicate that, as the stage of integration moves from independent operation to internal and on to external integration, the focus of information systems utilization should shift from infrastructural support to value creation management and logistical operations, and this change of IS utilization focus can lead to sustainable competitiveness.