Watermark Visibility Adjustable RVW Scheme for JPEG Images

Wireless Personal Communications - In digital images, visible watermarks are embedded to convey the ownership information directly to the world so that copyright violations can be prevented. The...     

Studies on the Inhibition of Mild Steel Corrosion by Rauvolfia serpentina in Acid Media

Alkaloid extract of Rauvolfia serpentina was tested as corrosion inhibitor for mild steel in 1 M HCl and H₂SO₄ using weight loss method at three different temperatures, viz., 303, 313, and 323 K, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope (SEM) studies. It is evident from the results of this study that R. serpentina effectively inhibits the corrosion in both the acids through adsorption process following Tempkin adsorption isotherm. The protection efficiency increased with increase in inhibitor concentration and temperature. Free energy of adsorption calculated from the temperature studies also revealed the chemisorption. The mixed mode of action exhibited by the inhibitor was confirmed by the polarization studies while SEM analysis substantiated the formation of protective layer over the mild steel surface.     

Rauvolfia serpentina-Mediated Green Synthesis of CuO Nanoparticles and Its Multidisciplinary Studies

Copper oxide nanoparticles(Cu O Nps) were successfully synthesized by solution combustion method using aqueous leaf extract of Rauvolfia serpentina as a fuel. The structure and morphology of the Cu O nanoparticles(Nps) were characterized by powder X-ray diffraction(PXRD), UV–visible spectroscopy(UV–visible), scanning electron microscopy(SEM), transmission electron microscopy(TEM), etc. The PXRD patterns reveal the formation of monoclinic phase with crystallite structure. SEM images indicate that the particles have sponge-like structure being highly porous and agglomerated with large surface area. The average crystallite sizes were found to be in the range of 10–20 nm by Scherrer's method. The Cu O Nps size was further confirmed by TEM. Further, Cu O Nps exhibit good photocatalytic activity for the photodegradation of trypan blue dye, indicating that it acts as a promising semiconducting material. The antibacterial properties of Cu O nanoparticles were investigated against pathogenic bacterial strains, namely Gram-ve Escherichia coli(NCIM-5051) and Pseudomonas desmolyticum(NCIM-2028) and Gram ?ve bacteria Staphylococcus aureus(NCIM-5022) using the agar well diffusion method.     

Software-driven sensor networks for short-range shallow water applications

Most existing underwater networks target deep and long range oceanic environments, which has led to the design of power hungry and expensive underwater communication hardware. Because of prohibitive monetary and energy cost of currently over-engineered communication hardware, dense deployments of shallow water sensor networks remain an elusive goal. To enable dense shallow water networks, we propose a network architecture that builds on the success of terrestrial sensor motes and that relies on the coupling of software modems and widely available speakers and microphones in sensor motes to establish acoustic communication links. In this paper, we analytically and empirically explore the potential of this acoustic communication system for the underwater environment. Our experimental approach first profiles the hardware in water after waterproofing the components with elastic membranes. The medium profiling results expose the favorable frequencies of operation for the hardware, enabling us to design a software FSK modem. Subsequently, our experiments evaluate the data transfer capability of the underwater channel with 8-frequency FSK software modems. The experiments within a 17 × 8 m controlled underwater environment yield an error-free channel capacity of 24 bps, and they also demonstrate that the system supports date rates between 6 and 48 bps with adaptive fidelity.     

Geometrical confinement of gadolinium-based contrast agents in nanoporous particles enhances T1 contrast

Magnetic resonance imaging contrast agents are currently designed by modifying their structural and physiochemical properties to improve relaxivity and to enhance image contrast. Here, we show a general method for increasing relaxivity by confining contrast agents inside the nanoporous structure of silicon particles. Magnevist, gadofullerenes and gadonanotubes were loaded inside the pores of quasi-hemispherical and discoidal particles. For all combinations of nanoconstructs, a boost in longitudinal proton relaxivity r(1) was observed: Magnevist, r(1) ≈ 14 mM(-1) s(-1)/Gd(3+) ion (～ 8.15 × 10(+7) mM(-1) s(-1)/construct); gadofullerenes, r(1) ≈ 200 mM(-1) s(-1)/Gd(3+) ion (～ 7 × 10(+9) mM(-1) s(-1)/construct); gadonanotubes, r(1) ≈ 150 mM(-1) s(-1)/Gd(3+) ion (～ 2 × 10(+9) mM(-1) s(-1)/construct). These relaxivity values are about 4 to 50 times larger than those of clinically available gadolinium-based agents (～ 4 mM(-1) s(-1)/Gd(3+) ion). The enhancement in contrast is attributed to the geometrical confinement of the agents, which influences the paramagnetic behaviour of the Gd(3+) ions. Thus, nanoscale confinement offers a new and general strategy for enhancing the contrast of gadolinium-based contrast agents.     

Effect of various sintering methods on microstructures and mechanical properties of titanium and its alloy (Ti–Al–V–X): A review

Titanium having high demand in aircraft industries because of its mechanical properties like high strength to weight ratio, high temperature performance and it’s resistant to corrosion. Therefore, Titanium and its alloys are used in airplane and engine applications. One of the major usages of alloy in the aircraft industries are Titanium alloy. By using Powder Metallurgy, the powder materials are compacted and sintered in the furnace to achieve high densities for the further process of the samples. In this paper reviews the various research investigations of Titanium and its alloy (Ti–% Al–% V–% X alloy), to optimize the microstructure and mechanical properties by various sintering methods like Conventional, Spark plasma and Microwave sintering techniques. From this the major advantages in the Spark plasma sintering tend to reduce the sintering time with high temperatures, achieving higher densities and improved microstructures tends to improve the mechanical properties of the material.     

One-dimensional simulation of multi pulse phenomena in dielectric-barrier atmospheric-pressure glow discharges

The dielectric-barrier configuration is commonly used to generate uniform, highly non-equilibrium atmospheric-pressure glow discharges. Although recent research has improved our understanding of these discharges, several questions relating to the structure and transient characteristics of the discharge remain to be answered. We employ a self-consistent, one-dimensional, model to simulate these discharges in helium. In particular, we address question of pulse formation and multi-pulse phenomena. The model provides excellent predictive capability for all trends concerning multiple pulse behavior. The appearance of multiple pulses with increasing external voltages is predicted accurately for the nominal operating frequency of 10 kHz. With decreasing frequencies down to 100 Hz, the weakening of the discharge pulse and the increasing number of pulses are also predicted. However, in the low frequency regime the prediction of the discharge phenomena is very sensitive to plasma chemistry model. Impurity effects appear to play an important role in this regime.     

Non-size-based membrane chromatographic separation and analysis of monoclonal antibody aggregates

Humanized monoclonal antibody produced by mammalian cell culture may contain significant amounts of antibody dimers and smaller amounts of higher order aggregates. These are undesirable in therapeutic formulations, and their content should be lower than specific allowable limits. Quantitative analysis of aggregate content is usually carried out by size exclusion chromatography (SEC), which is slow and often gives poorly resolved peaks. We describe a novel hydrophobic interaction membrane chromatography-based technique for rapid, non-size-based separation and analysis of the aggregate content in monoclonal antibody samples. The typical sample analysis time using this technique is less than 3 min, this being significantly faster than SEC. The technique gives excellent resolution of the antibody, its dimer, and higher order aggregates and could potentially be scaled up for large-scale manufacture of aggregate-free monoclonal antibody. This work also clearly shows that monoclonal antibody aggregates are more hydrophobic than the monomer form, a fact that could have significant theoretical and practical implications.     

Simultaneous extraction of optical transport parameters and intrinsic fluorescence of tissue mimicking model media using a spatially resolved fluorescence technique

We present a method based on spatially resolved fluorescence measurement for the simultaneous estimation of optical transport parameters, namely, the reduced scattering coefficient (micro s'), the absorption coefficient (micro a), and the intrinsic fluorescence spectra from turbid media. The accuracy of this approach was tested by conducting studies on a series of tissue-simulating phantoms with known optical transport properties. The estimated relative error in the values for micro s' and micro a using this technique was found to be < or =10%. Furthermore, the line shape and intensity of the intrinsic fluorescence recovered by using this approach were observed to be free from the distorting effects of the wavelength-dependent absorption and scattering properties of the medium, and they were in excellent agreement with the directly measured intrinsic fluorescence spectra of the fluorophores.