NOPR Collection:

Study of turbulent two-phase gas-solid flow in horizontal channels

2016-07-20T06:03:41Z

Title: Study of turbulent two-phase gas-solid flow in horizontal channels Authors: Lain, S Abstract: The present study deals with pneumatic conveying of spherical particles in a six meter long horizontal channel with rectangular cross-section from a numerical perspective. Calculations are done for spherical glass beads of different sizes with a mass loading of 1.0 kg particles/kg gas. Additionally, different wall roughnesses are considered. Air volume flow rate is kept constant in order to maintain a fixed gas average velocity of 20 m/s. The numerical computations are performed by the Euler/Lagrange approach in connection with a Reynolds stress turbulence model accounting for two-way coupling and inter-particle collisions. For the calculation of the particle motion, all relevant forces (drag, slip-shear and slip-rotational lift and gravity), inter-particle collisions and particle-rough wall collisions are considered. The agreement of the computations with the findings or earlier experiments are found to be satisfactory for mean and fluctuating velocities of both phases as well as for the normalized particle mass flux. Page(s): 128-136

Photocatalytic decomposition of acetaldehyde gas on TiO₂-SiO₂ thin film photocatalyst ― A kinetic analysis

2016-07-20T05:54:52Z

Title: Photocatalytic decomposition of acetaldehyde gas on TiO₂-SiO₂ thin film photocatalyst ― A kinetic analysis Authors: Aziz, Radhiyah Abdul; Sopyan, Iis Abstract: TiO₂-SiO₂ thin film photocatalysts with 5 (TF95/5) and 10 w/w% (TF90/10) SiO₂ contents have been prepared via sol-gel method. Characterization using X-ray diffractormeter and field emission scanning electron microscopy is performed to investigate the effect of SiO₂ doping on the TiO₂ thin film’s physico-chemical properties. The photocatalytic performance of the thin films is evaluated using the degradation of acetaldehyde gas at various initial concentrations under fixed intensity UV irradiation. A Langmuir-Hinshelwood kinetic model is used to analyze the kinetics of the photocatalytic reaction. It is found that the first order reaction rate constant (k) of the TF95/5 thin film photocatalyst (1.2438 µmol dm^-3 min^-1) is higher than that of TF90/10 thin film (0.3648 µmol dm^-3 min^-1). This is attributed to higher crystallinity of the TF95/5 thin film, resulting in more active charge carrier generation. However, TF90/10 thin film photocatalyst with smaller TiO₂ particles shows four times stronger adsorbability of acetaldehyde than TF95/5 due to its higher surface area. Page(s): 137-144

Application of response surface methodology and central composite design for the optimization of talc filler and retention aid in papermaking

2016-07-20T06:01:18Z

Title: Application of response surface methodology and central composite design for the optimization of talc filler and retention aid in papermaking Authors: Chauhan, Vipul S; Bhardwaj, Nishi K; Chakrabarti, Swapan K Abstract: Cationic polyacrylamide (CPAM) has been used as a retention aid with talc (hydrous magnesium silicate) filler to get the variation of ash in paper using response surface methodology based central composite design. The need of CPAM for varying dosage of talc filler is calculated statistically through the data of first pass ash retention (FPAR) using analysis of variance. The design is employed by selecting the dosages of talc filler and CPAM as model factors to get the variation of ash in paper. The dosages of talc and CPAM range from 250 g/t to 750 g/t and from 50 g/t to 400 g/t pulp respectively. The results of first order factorial design show that both independent variables have significant effect on increasing the ash in paper. At any particular filler addition level, the increase in CPAM addition enhances the ash and FPAR. Optimum conditions to get around 55% FPAR and 15% ash in paper are found to be 382 kg/t talc and 230 g/t CPAM. The linear equations obtained from the designed experiments can be used to predict the dosage of inputs (talc and CPAM) on the basis of desired outputs (ash content and FPAR). Page(s): 121-127

Spectrophotometric determination of meloxicam by sodium nitroprusside and 1,10-phenanthroline reagents in bulk and its pharmaceutical formulation

2016-07-20T05:58:01Z

Title: Spectrophotometric determination of meloxicam by sodium nitroprusside and 1,10-phenanthroline reagents in bulk and its pharmaceutical formulation Authors: Gurupadayya, B M; Trinath, M N; Shilpa, K Abstract: Two simple and selective spectrophotometric methods have been developed for the quantitative determination of meloxicam in pure form and in pharmaceutical formulations. The first method is based on the electron transfer reaction of drug with sodium nitroprusside in presence of hydroxyl amine HCl and the absorption maxima is recorded at 363 nm (Method A). Second method is based on the formation of a complex of drug with ferric chloride and followed by coupling with 1,10-phenanthroline, and the absorption maximum is recorded at 343 nm (Method B). Both the methods follow Beer’s range in the concentration range 4-20 μg mL^-1 and 10-50 μg mL^-1 for Methods A and B respectively. Good correlation coefficients (0.9955-0.9973) are observed between absorbance and corresponding concentrations of the drug. The calculated apparent molar absorptivity values are found to be 0.6079 × 10^-4and 0.4849 × 10^-4 mol^-1cm^-1for the Methods A and B respectively. The limits of detection and quantification are also reported for both spectrophotometric methods. Intra-day & inter-day precisions and the accuracy of the methods have also been evaluated. No interference is observed from common pharmaceutical adjutants. The reliability of the methods is further ascertained by performing recovery tests by standard addition method. Page(s): 111-115

NOPR Collection:

Study of turbulent two-phase gas-solid flow in horizontal channels

Photocatalytic decomposition of acetaldehyde gas on TiO2-SiO2 thin film photocatalyst ― A kinetic analysis

Application of response surface methodology and central composite design for the optimization of talc filler and retention aid in papermaking

Spectrophotometric determination of meloxicam by sodium nitroprusside and 1,10-phenanthroline reagents in bulk and its pharmaceutical formulation

Photocatalytic decomposition of acetaldehyde gas on TiO₂-SiO₂ thin film photocatalyst ― A kinetic analysis