BTC Image Coding Using Vector Quantization

This paper describes source encoding of the outputs of a block truncation coder (BTC), namely, the overhead statistical information and the truncated block. The statistical overhead and the truncated block exhibit properties which can be effectively used for their quantization as vectors. Vector quantization of these BTC outputs results into reduction of the bit rate of the coder. The bit rate reduces up to 1.5 bits/ pel if vector quantization is used on one of the outputs; i.e., either the overhead information or the truncated block. By vector quantizing both the BTC outputs the bit rate can he reduced up to 1.0 bits/pel without introducing many perceivable errors in the reconstructed output.     

Hydrodynamic study on radially cross-flow fluidized bed multi-staged ion-exchange column

A hydrodynamic study was carried out on our patented radially cross-flow fluidized bed staged column, with the salt laden water and solid resins flowing counter-currently, to determine the loading/flooding criterion for a stable operation of the column, and also to ascertain the mal-distribution in flow. Residense time distribution measurements were taken to address the latter part of the study. The data collected from the hydrodynamic measurements show a wider range of liquid and solid flowrates that can be used for the stable operation of the column, in comparison to that obtained in the conventional multi-staged column. The extent of mal-distribution or channeling is also relatively smaller in the former. The observations are consistent with the mass-transfer results obtained in our recent study, where the separation of dissolved solids using the radially cross-flow ion exchange column was found to be 40% larger than that in the conventional column.     

Structural and ferroelectric properties of lanthanum modified BPZT ceramics

Lanthanum modified Ba_0.80Pb_0.20Ti_0.90Zr_0.10O₃ (BPZT) ceramics with composition Ba_0.80−xLa_x Pb_0.20Ti_0.90Zr_0.10O₃; x = 0–0.01 in steps of 0.0025 were prepared by conventional solid state method. All the samples were sintered at 1325 °C after compacting in circular discs. Detailed structural and ferroelectric properties were carried out for sintered specimens. X-ray diffraction analysis for all the sintered specimens shows tetragonal structure with perovskite. Coercive field (E_c) and remanent polarization (P_r) to spontaneous polarization (P_s) ratio (P_r/P_s) was found to decrease with increase in temperature. P_r/P_s ratio was found to decrease with increase in x, except x = 0.0025.     

Low-fat sweet syrup cheese ball (Rosogolla) manufacturing and effect of lowering fat on quality

Low-fat sweet syrup cheese ball (Rosogolla) was manufactured by using low-fat cow milk and implementing six different combinations viz. type of chhana and two different concentrations (40 and 50o Brix) of cooking medium. Experimental Rosogolla samples and control were analysed for physico-chemical, textural and sensory properties. A 40o Brix concentration of sugar syrup as a cooking medium gave a highly acceptable low-fat Rosogolla. Average composition of low-fat Rosogolla is, moisture—49.83%, fat—4.66%, protein—11.85%, sorbitol—32.41% and ash—0.90%. Rheological properties of the most acceptable low-fat Rosogolla were hardness—6.78 N, springiness—5.72 mm, gumminess—3.2 N, chewiness—18.92 Nmm and stiffness—0.95 N/mm.     

Structures and Images of Novel Derivatives of Carbon Nanotubes, Fullerenes and Related New Carbon Forms

In the light of the finding that carbon nanotubes get functionalized on reaction with acid and other oxidizing agents, the structures and shapes of nanotube derivatives resulting from possible reaction between functionalized nanotubes, are obtained by an energy minimization procedure and the structures, so obtained, are compared with the observed microscopic images. The shapes of fullerene -like and nanotupe - like structures containing seven - membered rings, in addition to six and five - membered rings, are depicted along with the structures of bent nanotubes containing similar ring systems. Diamond - graphite hybrid structures which constitute an important class of carbon materials are also investigated.     

Influence of polymer viscosity on the morphological and opto‐electronic behavior of polysiloxane dispersed ferroelectric liquid crystal composite thin films

Poly(dimethyl)siloxanes of different viscosity have been synthesized by hydrolytic condensation of dimethyldichloro silane. Polysiloxane dispersed ferroelectric liquid crystal (PDFLC) composite films were prepared simultaneously by solvent induced and polymer induced phase separation techniques (SIPS and PIPS, respectively). These composite films were prepared by mixing polymer and ferroelectric liquid crystal mixture in diethyl ether and then adding 0.2% of room temperature vulcanizer for crosslinking. Film morphology, droplet size, and electro‐optic parameters of PDFLC systems have been studied by using polysiloxanes of different viscosity. We show that the polymer viscosity affects the droplet size, morphological uniformity, electro‐optic properties, and also the extent to which the phase separation is complete. These composite systems show the switching time of few microseconds. Structure‐property correlation in these materials have been studied and explained on the basis of polysiloxane viscosity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 159–166, 2004     

Influence of different polyesters and their molecular weight on the textural and electrooptical behavior of polymer‐dispersed liquid crystals

The textural and electrooptical behavior of a nematic liquid crystal (LC) dispersed in a flexible and rigid polyester was studied. The dispersion of LC in the polymer matrix and light transmission through the polymer‐dispersed liquid crystal (PDLC) is governed by the nature of the polymer, its molecular weight, and the applied voltage. It was observed that the transmission of light and the dispersion of LC maximizes their respective values at the minimum molecular weight irrespective of the nature of the polymer and at the maximum voltage. The reason is the predominance of chain alignment over entanglement at the minimum molecular weight. As molecular weight increases, the transmission of light as well as the dispersion of LC in the polymer may increase or decrease depending on the predominance of chain entanglement or chain alignment. The alignment of LC droplets in the direction of the applied voltage is increased by an increase in the applied voltage, causing enhancement of the light transmission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 284–289, 2003     

Fabrication of a proton exchange membrane via blended sulfonimide functionalized polyamide

A novel linear non-fluorinated sulfonimide functionalized polyamide (SPA) polymer electrolyte was successfully synthesized via an aromatic sulfonimide monomer with superior thermal stability and superacidity. The aromatic sulfonimide remains stable below 220 °C. To fabricate membranes with strong mechanical strength and dimensional stability, the polymer was blended with various quantities of PVdF. The PVdF/SPA blend membranes exhibit an excellent capacity of water uptake and high dimensional stability. However, their proton conductivity was found to be substantially lower than that of Nafion 211. Analysis on the SEM images of the PVdF/SPA blend membranes reveals that the low proton conductivity is primarily caused by the large pore structures (>1 μm), which lead to breakdown of the continuous proton transport channels.     

Analysis of Dielectric and Electro-optic Responses of Nanomaterials Doped Ferroelectric Liquid Crystal Mixture

Dielectric and rotational viscosity measurements of a multi-component ferroelectric liquid crystal mixture were performed by adding a small concentration (0.01 wt%) of silica and multi walled carbon nanotubes (MWCNTs). Liquid crystals turn out to be outstanding hosts for nanomaterials. A remarkable increase in the rotational viscosity was noticed in CNT doped system as compared to silica doped same liquid crystal system. Comparison of dielectric studies shows higher value of permittivity and dielectric losses for silica-doped sample than those of CNT doped sample. The results have been interpreted both experimentally and theoretically.