A 4-quadrant curvelet transform for denoising digital images

The conventional discrete wavelet transform (DWT) introduces artifacts during denoising of images containing smooth curves. Finite ridgelet transform (FRIT) solved this problem by mapping the curves in terms of small curved ridges. However, blind application of FRIT all over an image is computationally heavy. Finite curvelet transform (FCT) selectively applies FRIT only to the tiles containing small portions of a curve. In this work, a novel curvelet transform named as 4-quadrant finite curvelet transform (4QFCT) based on a new concept of 4-quadrant finite ridgelet transform (4QFRIT) has been proposed. An image is band pass filtered and the high frequency bands are divided into small non-overlapping square tiles. The 4QFRIT is applied to the tiles containing at least one curve element. Unlike FRIT, the 4QFRIT takes 4 sets of radon projections in all the 4 quadrants and then averages them in time and frequency domains after denoising. The proposed algorithm is extensively tested and benchmarked for denoising of images with Gaussian noise using mean squared error (MSE) and peak signal to noise ratio (PSNR). The results confirm that 4QFCT yields consistently better denoising performance quantitatively and visually.     

Synthesis of poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide-<Emphasis Type="Italic">b</Emphasis>-<Emphasis Type="Italic">N</Emphasis>-vinylcarbazole) copolymers via RAFT polymerization and its stimuli responsive morphology in aqueous media

Here, we report the successful synthesis of series of stimuli responsive amphiphilic diblock copolymers (SRABCs) poly(N-isopropylacrylamide-b-N-vinylcarbazole) [poly(NIPAAm-b-NVK)] through reversible addition fragmentation chain transfer (RAFT) polymerization. Copolymers with fixed hydrophilic [poly(NIPAAm)] block length and variable (with three different) hydrophobic [poly(NVK)] block lengths were synthesized and the block length ratio was confirmed from their molecular weight data. The self-assembly nature of synthesized block copolymers was confirmed by determining critical micelle concentration (CMC). Self-assembled block copolymers showed rice-grain like morphology for copolymers having equivalent hydrophobic/hydrophilic chain length but in case of block copolymers having smaller and bigger hydrophobic chain length with respect to hydrophilic chain length displayed vesicular morphology. The thermo and pH responsiveness of the block copolymers was found to be influenced by variation in length and chemical composition of the blocks. Due to their thermo and pH responsiveness resulted self-assembled structures underwent morphology transitions from vesicular and rice grain like to micellar structure in aqueous medium. The probable applications of the studied stimuli responsive amphiphilic diblock copolymers can be found in the nanotechnology and biotechnology are indicated.

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Graphical abstract Synthesis, self-assembly and stimuli responsiveness of poly(NIPAAm-b-NVK) copolymers.

     

Reduction of Manavalakurichi ilmenite by Activated Charcoal in Presence of Catalyst

The reserves of ilmenite are abundant in India; however, it needs to be upgraded to synthetic rutile. The carbothermic reduction is one of the most effective processing methods to produce TiO₂. However, it is more energy intensive method as is carried out at high temperature. The present paper studies the carbothermic reduction of Manavalakurichi ilmenite concentrate by charcoal in the presence of sodium carbonate. The sodium carbonate as catalyst has significant effect on kinetics of reduction. It is able to save energy by reducing the reduction temperature for same degree of reduction at high temperature without catalyst.     

Direct synthesis and characterization of high temperature stable anatase TiO2 nanospheres from peroxo-titanium complex

Phase pure anatase nanospherical TiO₂ has been obtained by sol dissolution method using TiCl₃ as a precursor. The effect of annealing temperature on the properties of TiO₂ has been studied and discussed. The structural, morphological and optical properties of the synthesized powder were determined using XRD, SEM, AFM, TEM, UV-Visible and flourimetry. The anatase phase of synthesized TiO₂ using this method has a higher thermal stability up to 800 °C after which it is transformed into rutile phase. The crystallite size increases with the annealing temperature. The shift in absorption towards the visible region is observed for the anatase phase. The material showed fluorescence properties emitting light of 410 nm. The study also evaluated the photodegradation of a congo red as model dye. The TiO₂ powder has shown good catalytic properties due to its high surface area. The proposed method is simple, fast, and efficient and reproducible for the synthesis of homogeneous nanospheres of TiO₂, which will be applicable in possible optoelectronic devices.     

Formulation development and accelerated stability testing of a novel sunscreen cream for ultraviolet radiation protection in high altitude areas

The present study is aimed at the development of a sunscreen cream for use in high altitude areas which have been found to possess superior sun protection factor (SPF) along with remarkable antioxidant activity. The topical formulation is a standard oil-in-water emulsion of a combination of United States Food and Drug Administration (US FDA) approved ultraviolet filters; along with melatonin and pumpkin seed oil. The in-silico optimized formulation was characterized using established methods and the stability study was carried out as per International Conference on Harmonization guidelines. The formulation was prepared after requisite pre-formulation analysis by Fourier-transform infrared spectroscopy, differential scanning calorimetric and thermogravimetric analyses; followed by characterization based on color, odor, phase separation, spreadability, specific gravity, homogeneicity, centrifugation and sensitivity. For the stability study, a total of three samples from three batches of the finished product were subjected to the stability study. The samples were analyzed for content uniformity, pH, in vitro SPF, rheology, zeta potential, droplet diameter and microbial analysis of the 0th day and also the the end of the storage period. Results obtained from the stability study indicated that the formulation possesses 50+ in vitro SPF value and remained stable for 6?months and 12?months under storage at 40?±?2?°C and 75?±?5% relative humidity; and ?20?°C?±?5?°C respectively.     

Comparative studies on Performance evaluation of a two stroke copper coated spark ignition engine with alcohols with catalytic converter

AimInvestigations were carried out to evaluate the performance of a two-stroke, single cylinder, spark ignition (SI) engine, with alcohol blended gasoline (80% gasoline, 20% methanol by vol; 80% gasoline and 20% ethanol by volume) having copper coated engine [CCE, copper-(thickness, 300 μm) coated on piston crown, inner side of cylinder head] provided with catalytic converter with sponge iron as catalyst and compared with conventional SI engine (CE) with pure gasoline operation.Study designPerformance parameters of brake thermal efficiency, exhaust gas temperature and volumetric efficiency were determined at various values of brake mean effective pressure (BMEP).MethodologyA microprocessor-based analyzer was used for the measurement of carbon monoxide (CO) and un-burnt hydro carbons (UBHC) in the exhaust of the engine at various values of BMEP. Aldehydes were measured by dinitrophenyl hydrazine (DNPH) method at peak load operation of the engine.Brief resultsCCE with alcohol blended gasoline considerably reduced pollutants in comparison with CE with pure gasoline operation. Catalytic converter with air injection significantly reduced pollutants with test fuels on both configurations of the engine. Gasohol improved the performance of the both versions of the engine in comparison with methanol blended gasoline. On the other hand, methanol blended gasoline effectively reduced the emissions when compared with gasohol in both versions of the engine.     

Proposal of Charge Plasma Based Recessed Source/Drain Dopingless Junctionless Transistor and its Linearity Distortion Analysis for Circuit Applications

Silicon - Linearity and intermodulation distortion (IMD) analysis examined major reliability issues that arise due to the non-linear behavior of the devices in analog/RF circuit applications. In...     

Determination of Clozapine and its Metabolite,Norclozapine in Various Biological Matrices Using High-Performance Liquid Chromatography

Purpose. To develop and validate an HPLC method for the quantitation of clozapine and its metabolite, norclozapine in human plasma, rat plasma, and the various human plasma lipoprotein fractions. Methods. Using liquid-liquid extraction, clozapine, and norclozapine are extracted from the biological matrix with MTBE. After concentration, the residue was reconstituted in 1mM HCl and injected on to a C6 Phenyl column (3μm, 2.0×150 mm). Mobile phase was 10mM Ammonium Acetate, pH 5—Acetonitrile—Methanol (5:3:2, v/v/v). Loxapine served as the internal standard. Absorbance was measured at 254 nm. Results. Quantitation limits for clozapine and norclozapine was 100 ng/mL and 50 ng/mL, respectively. Recovery for both clozapine and norclozapine was near 100%. Percent accuracy for intraday variability in human plasma, rat plasma, and human TRL, HDL, LDL, and LPDP lipoprotein fraction was between 92 to 113% for both analytes. Intraday precision for the same matrices was less than 9% CV for both analytes. Percent accuracy and precision for interday variability in human plasma was 97 to 103% and less than 10% CV, respectively. Samples were stabile in the autosampler for 80 h at 10°C and on the benchtop for 2 h. It should be noted, Clozapine-N-oxide, which is a known metabolite of Clozapine, was not determined since it is not clinically active. Conclusions. This method is a simple, fast and robust HPLC assay for the determination of clozapine and norclozapine in various matrices and lipoprotein fractions.     

VLSI design of memory-efficient, high-speed baseline MQ coder for JPEG 2000

The embedded block coding with optimized truncation (EBCOT) algorithm is the heart of the JPEG 2000 image compression system. The MQ coder used in this algorithm restricts throughput of the EBCOT because there is very high correlation among all procedures to be performed in it. To overcome this obstacle, a high throughput MQ coder architecture is presented in this paper. To accomplish this, we have studied the number of rotations performed and the rate of byte emission in an image. This study reveals that in an image, on an average 75.03% and 22.72% of time one and two shifts occur, respectively. Similarly, about 5.5% of time two bytes are emitted concurrently. Based on these facts, a new MQ coder architecture is proposed which is capable of consuming one symbol per clock cycle. The throughput of this coder is improved by operating the renormalization and byte out stages concurrently. To reduce the hardware cost, synchronous shifters are used instead of hard shifters. The proposed architecture is implemented on Stratix FPGA and is capable of operating at 145.9 MHz. Memory requirement of the proposed architecture is reduced by a minimum of 66% compared to those of the other existing architectures. Relative figure of merit is computed to compare the overall efficiency of all architectures which show that the proposed architecture provides good balance between the throughput and hardware cost.