Curvelet Transform Based Watermarking for Telemedicine

Now a days telemedicine is a proactive research area and gaining more engrossment. Digital transmission of medical imaging, remote evaluation and diagnosis together are termed as Telemedcine and it has increasingly gained prominence in the recent times. Remote specialist reckons intemperately on scan images or medicinal images and data of patient for devising diagnostic conclusion. While imparting a scan image (clinical picture) to remote authority, the significant part (ROI) in it may be altered by interlopers. The remote authority must recover the ROI in a clinical picture on the off chance that it has been altered. This paper presents a novel robust watermarking method founded on Curvelet Transform to recover the ROI in medical image in case it is altered. The proposed method hides ROI information inside diagnostically insignificant part in medical image through Curvelet Transform. Experiments carried out using this novel technique have proven that the ROI in medical image is restored to its original state.

     

On Padé approximations, quadratic stability and discretization of switched linear systems

In this note we consider the stability preserving properties of diagonal Padé approximations to the matrix exponential. We show that while diagonal Padé approximations preserve quadratic stability when going from continuous-time to discrete-time, the converse is not true. We discuss the implications of this result for discretizing switched linear systems. We also show that for continuous-time switched systems which are exponentially stable, but not quadratically stable, a Padé approximation may not preserve stability.     

Modeling Freckle Segregation with Mesh Adaptation

Modeling the formation of macroscopic segregation channels during directional solidification processes has important applications in the casting industry. Computations that consider thermosolutal convection involve different length scales ranging from the small solute boundary layer at the dendrite tips to the characteristic size of the casting. In general, numerical models of solidification in the presence of a developing mushy zone are computationally inefficient because of nonlinear transport in an anisotropic porous medium. In the current work, mesh adaptation with triangular finite elements is used in conjunction with an efficient fractional-step solver of the momentum equations to predict the occurrence of channel-type segregation defects or freckles. The triangulations are created dynamically using an unstructured grid generator and a refinement criterion that tracks the position of the channel segregates. The efficiency of mesh adaptation is illustrated with simulations showing channel formation and macrosegregation in directional solidification of a Pb–Sn alloy.     

One-pot synthesis of conducting graphene-polymer composites and their strain sensing application

In situ reduction of graphite oxide in polymer powder has been implemented using focused solar electromagnetic radiation. The simultaneous reduction of graphite oxide, melting of the polymer and embedding of reduced graphite oxide nanoflakes in polymer offer a new way of synthesizing conducting graphene/polymer composites. An electromechanical application of the present reduced graphite oxide-PVDF nanocomposite has been proposed with a gauge factor of 12.1.     

Functionalized Graphene–PVDF Foam Composites for EMI Shielding

Novel foam composites comprising functionalized graphene (f‐G) and polyvinylidene fluoride (PVDF) were prepared and electrical conductivity and electromagnetic interference (EMI) shielding efficiency of the composites with different mass fractions of f‐G have been investigated. The electrical conductivity increases with the increase in concentration of f‐G in insulating PVDF matrix. A dramatic change in the conductivity is observed from 10^?16 S · m^?1 for insulating PVDF to 10^?4 S · m^?1 for 0.5 wt.% f‐G reinforced PVDF composite, which can be attributed to high‐aspect‐ratio and highly conducting nature of f‐G nanofiller, which forms a conductive network in the polymer. An EMI shielding effectiveness of ≈20 dB is obtained in X‐band (8–12 GHz) region and 18 dB in broadband (1–8 GHz) region for 5 wt.% of f‐G in foam composite. The application of conductive graphene foam composites as lightweight EMI shielding materials for X‐band and broadband shielding has been demonstrated and the mechanism of EMI shielding in f‐G/PVDF foam composites has been discussed.

     

Graphene-based engine oil nanofluids for tribological applications

Ultrathin graphene (UG) has been prepared by exfoliation of graphite oxide by a novel technique based on focused solar radiation. Graphene based engine oil nanofluids have been prepared and their frictional characteristics (FC), antiwear (AW), and extreme pressure (EP) properties have been evaluated. The improvement in FC, AW, and EP properties of nanofluids is respectively by 80, 33, and 40% compared with base oil. The enhancement can be attributed to the nanobearing mechanism of graphene in engine oil and ultimate mechanical strength of graphene.     

Targeted Delivery of siRNA‐Generating DNA Nanocassettes Using Multifunctional Nanoparticles

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double‐stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor‐targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double‐stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor‐mediated internalization should enhance the therapeutic effect of the siRNA‐mediated cancer therapy.     

Selection of Gravity Separators for the Beneficiation of the Uljin Tin Ore

Gravity separation is typically used in the beneficiation of tin ores as the density difference between the valuable and associated gangue minerals is significant. In the present investigation, a cassiterite sample collected from the Uljin deposit in South Korea has been subjected to different gravity separators to evaluate the separation efficiency. The selection of gravity units has been made based on performance evaluation following heavy liquid separation and assessment of grade/recovery curves and Tromp curve methods. In addition, a gravity separation index (GSI) has been proposed that is simpler than other methods for assessing the performance of gravity separators.     

Minimization of fines generation in size reduction of coals by impact crusher

In Bubbling Fluidized Bed Combustors (BFBC) utilizing coal, efficient combustion requires that feed size of coal particles be in the maximum size range of 2 to 6 mm. This requires that the comminution process be effective. In this work, various types of coals have been comminuted in an impact crusher. The size reduction process is characterized by four process parameters and relevant properties of the coal samples. Taguchi's design of experiment was used to minimize the number of experiments done to obtain meaningful results. It was concluded from the experiments that among process parameters, RPM has a more prominent effect on generation of fines compared to feed rate, feed size and gap setting. Among coal properties, volatile matter, ash content and fixed carbon have significant effect, followed by moisture content. RPM has relatively less influence on coarse particle (> 6 mm) content. An empirical correlation has been formulated based on the data to predict the generation of fines for a given set of process parameters and physical properties of coals. The results obtained using the model was within the acceptable accuracy when compared to the experimental data. The same correlation has also been applied successfully to fit the cement production from a plant, indicating that it has merit beyond the laboratory and that the specific type of crusher is immaterial, provided the mechanism of size reduction remains the same.