Experimental study on the attrition and size distribution of bed material in a recirculating fluidized bed

An experimental study was performed on the attrition of the bed materials in a recirculating fluidized bed (RCFB) using Indian standard (IS) grade I sand (size between 2.0 and 1.0?mm) at ambient conditions. Experiments were performed with superficial air velocity ranging from 7.13 to 9.16?m/s, bed inventory of 7–10?kg, and a spacing of 0.085?m between the jet top and draft tube bottom. The main objective of the study was to investigate the effects of operation time on the attrition and size distribution of sand particles in a RCFB. It was noticed that the prime mode of attrition of bed materials was abrasion, not fragmentation. Reduction in the downcomer bed height was observed with increasing operation time. It indicates that attrition was significant and fines were elutriated out with the fluidizing air. Furthermore, variations in the shape, size, and harmonic diameter of particles were studied with increasing operation time. It has been observed that the coefficient of uniformity and coefficient of curvature showed increasing patterns. It specifies that particles of different size ranges and fines were formed due to attrition of particles. At the end of the operation, it was found that a significant amount of fines was elutriated with fluidizing air from the reactor.     

Movement abnormalities and the progression of prodromal symptomatology in adolescents at risk for psychotic disorders.

The link between movement abnormalities and psychotic disorders is presumed to reflect common neural mechanisms that influence both motor functions and vulnerability to psychosis. The prodromal period leading to psychotic disorders represents both a viable point for intervention and a developmental period that, if studied, could shed light on etiology; however, no published studies have examined the temporal progression of this link. A group with high levels of prodromal symptomatology (i.e., adolescents with schizotypal personality disorder [SPD]; n = 42) and both psychiatric controls (with other personality disorders or conduct disorder [OD]; n = 30) and nonpsychiatric controls ([NC]; n = 49) were recruited. Videotapes of structured psychiatric interviews were coded for movement abnormalities by raters blind to participants' diagnostic status, and follow-up assessments were conducted 1 year later. Controlling for psychotropic medications, the authors found that adolescents with SPD exhibited significantly more motor abnormalities in the face and upper body than did OD and NC controls. At baseline, movement abnormalities were positively correlated with the severity of positive, negative, and total prodromal symptoms. Within the SPD group, baseline movement abnormalities predicted symptom severity 1 year later. Movement abnormalities represent an early risk indicator that may be predictive of later symptom severity and potentially of psychosis onset. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nanocomposite Hydrogel Materials for Defective Cartilage Repair and Its Mechanical Tribological Behavior—A Review

Osteoarthritis (OA) is a regressive ailment that affects a large population of patients. The most common symptoms of OA in humans are cartilage abnormalities. Hydrogels are excellent candidates for cartilage regeneration and are widely accepted as implants. In the past few decades, numerous types of hydrogels have been synthesized to repair cartilage defects. This study highlights recent advances in hydrogel development for the treatment of cartilage defects. In addition, the detailed progression of tailored nanocomposite hydrogels is summarized, and emphasis has been placed on the mechanical properties, especially the tribological behavior of the developed nanocomposite hydrogels.     

Green approach towards hydrolysing wheat gluten using waste ingredients from pineapple processing industries

In this work, wheat gluten was hydrolysed with pineapple crude extract, obtained from pineapple core which is a waste from the pineapple processing industry. The efficacy of crude pineapple extract was at par with the commercial bromelain in terms of hydrolysing wheat gluten. The hydrolysis proceeded at a rapid rate during the first 60 min, then slowed down till 120 min, followed by a further steep rise until 180 min and a very slow reaction up to the 24-h incubation period. The resulting hydrolysates had a fair solubility (>40%) over a pH range of 2–10. The molecular masses of the identified mixture of peptides ranged between 500 and 5000 Da, with 16% and 79% of the identified peptides in the range 0.5–1.0 and 1.0–2.0 kDa, respectively. The functional properties of the hydrolysates were remarkably better than the original gluten.     

Effects of the attrition of bed material on the solid circulation rate in a recirculating fluidized bed

Effects of attrition of bed material on the solid circulation rate in a recirculating fluidized bed (RCFB) were studied in detail. Effects of different operating and design parameters such as operation time, superficial velocity, bed inventory, particle size, and spacing between jet top and draft tube bottom on the solid circulation rate in terms of attrition were studied. A mathematical model was developed on the basis of experimental results to identify the effects of attrition of bed particles on the solid circulation rate incorporating the effects of the various operating and design parameters. To develop the model, dimensional analysis and nonlinear regression were used. The model equation was a nonlinear equation, which implies a relationship between the solid circulation rate and other operating and design parameters. The model equation can estimate the solid circulation rate over a range of operation time and other parameters. Decrease in solid circulation rate can be predicted with increasing operation time, using the model equation.     

Synthesis of Chevrel phase $$(\hbox {Cu}_{1.8}\hbox {Mo}_{6}\hbox {S}_{8})$$ in composite with molybdenum carbide for hydrogen evolution reactions

Sustainable hydrogen generation from water electrolysis using renewable energy sources is the most promising pathway for future energy and hydrogen economy. Here, the Chevrel phase \((\hbox {Cu}_{1.8}\hbox {Mo}_{6}\hbox {S}_{8})\) was synthesized in composite with \(\hbox {Mo}_{2}\hbox {C}\) and good hydrogen evolution activity in acidic media has been demonstrated. Bundles of nanowires were formed in the templated synthesis route. The composites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and elemental analysis. Detailed electrochemical analysis reveals that MCS-Cu50 composite exhibits higher hydrogen evolution reaction (HER) activity with \(71.4\,\hbox {mA}\,\mathrm{cm}^{-2}\) current density at an overpotential of 400 mV. It requires 250 mV overpotential to produce \(10\,\hbox {mA}\,\mathrm{cm}^{-2}\) current density for HER.     

Effect of Graded Dispersion of SiC Particles on Dielectric Behavior of SiC/Epoxy Composite

Silicon - Gradient structures mainly boost the dielectric and mechanical properties of composites. Herein, the fabrication of silicon carbide (SiC)/epoxy gradient composites via centrifugal casting...     

Luciferase-based assay for adenosine: application to S-adenosyl-L-homocysteine hydrolase

S-Adenosyl-L-homocysteine hydrolase (SAHH) catalyzes the reversible conversion of S-adenosyl-L-homocysteine (SAH) to adenosine (ADO) and L-homocysteine, promoting methyltransferase activity by relief of SAH inhibition. SAH catabolism is linked to S-adenosylmethionine metabolism, and the development of SAHH inhibitors is of interest for new therapeutics with anticancer or cholesterol-lowering effects. We have developed a continuous enzymatic assay for adenosine that facilitates high-throughput analysis of SAHH. This luciferase-based assay is 4000-fold more sensitive than former detection methods and is well suited for continuous monitoring of ADO formation in a 96-well-plate format. The high-affinity adenosine kinase from Anopheles gambiae efficiently converts adenosine to adenosine monophosphate (AMP) in the presence of guanosine triphosphate. AMP is converted to adenosine triphosphate and coupled to firefly luciferase. With this procedure, kinetic parameters (K(m), k(cat)) for SAHH were obtained, in good agreement with literature values. Assay characteristics include sustained light output combined with ultrasensitive detection (10(-7) unit of SAHH). The assay is documented with the characterization of slow-onset inhibition for inhibitors of the hydrolase. Application of this assay may facilitate the development of SAHH inhibitors and provide an ultrasensitive detection for the formation of adenosine from other biological reactions.     

Electrodeposition of HgCdTe thin films

Hg_xCd_1−xTe thin films in the compositional range x=0.05–0.6 were grown on SnO₂-coated glass substrates using the electrodeposition technique. The electrochemical bath consisted of aqueous solutions of CdCl₂, HgCl₂ and Te reacted with HNO₃, along with a complexing agent CH₃CN (acetonitrile). The conditions for the growth of HgCdTe from such a bath were ascertained with the help of cyclic voltammetry (CV) curves. Studies indicate that single-phase HgCdTe can be electrodeposited from the bath only if it is thoroughly mixed over a period of time, prior to the deposition. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy and electron microprobe studies. XRD data show that single-phase material was obtained over the whole range of compositions studied. The films were polycrystalline having the cubic fcc structure and the (1 1 1) orientation. The best stoichiometry HgCdTe films grown from the baths of composition X=0.15, 0.3 and 0.6 were obtained at deposition potentials 0.65, 0.7 and 0.75 V (versus saturated calomel electrode (SCE)) respectively, the corresponding film compositions being x=0.16, 0.4 and 0.6, respectively.     

Cloud fraction retrieval using data from Indian geostationary satellites and validation

ABSTRACT

Cloud fraction (CF) is known as the dominant modulator of Earth’s radiation budget, thus regarded as Essential Climate Variable. CF is retrieved using Indian geostationary satellites Kalpana-1 and Indian National Satellite System (INSAT-3D) by calculating the fraction of area covered by the clouds in a given pixel divided by the total area of the pixel. The technique uses multi-channel thresholding for three channels in Kalpana-1, that is, thermal, visible, and water vapour, and four channels in INSAT-3D with mid-infrared channel in addition to the three mentioned for Kalpana-1. A 2-year record of CF at 30-min intervals was generated for the Indian region using the Kalpana-1 and INSAT-3D data. The retrieved CF data were compared against Moderate Resolution Imaging Spectroradiometer (MODIS) CF product in the near vicinity of simultaneous data availability (i.e., within ±15 min interval). This product agrees with MODIS (correlation coefficient 80%) with a root mean square error (RMSE) of 0.30, in spite of ±15 min of time difference between both the satellites. In addition, ground-based Total Sky Imager (TSI-440) retrieved data over Pune is used to validate the satellite retrieved CF over the same region. The probability of detection between retrieved CF and ground-based data is relatively more for range of CF between 0.00 and 0.25, that is, 90% and more than 20% for CF greater than 0.50. In view of the close agreement between retrieved CF from Kalpana-1 and INSAT-3D with MODIS and TSI-440, this product is operational and is being made available through National Information System for Climate and Environment Studies portal for use in better understanding of climate.