Nonpremixed bluff-body burner flow and flame imaging study

A nonpremixed bluff-body burner flow and flame have been studied using planar flow visualization and species concentration imaging techniques. The burner consists of a central jet of CH ₄ in a cylindrical bluff-body and an outer coflowing-air stream. Planar flow visualization, using Mie scattering from seed particles added to the fuel jet, Raman scattering from CH ₄ and laser-induced fluorescence of CH combined with Raman scattering of CH ₄ provided information on turbulent flow, mixing and combustion. The CH ₄ imaging system utilized two cameras, which enhanced the dynamic range of the diagnostic system by a factor of 10 over a single-camera system. It was observed that the fuel jet stagnated on the axis due to interaction with the high velocity air flow. The flow and mixing were found to have significant coherent and noncoherent, large-scale, time-varying structures. The detailed CH ₄ Raman and CH fluorescence measurements of an air-dominated bluff-body flame revealed that the stagnation zone governs mixing and flame stability. Through large-scale mixing, the stagnated jet feeds the recirculation zone and also creates a favorable condition to stabilize the flame detached from the bluff-body. The instantaneous flame zone, as defined by CH, was found to be narrow and concentrated in an envelope around the stagnation zone. This narrow flame characteristic is consistent with that observed for jet flames. Although the internal structure of the flame envelops have not yet been defined, these results suggest that this bluff-body flame can be modeled by a flame sheet type approach, where the reaction front is captured by the large-scale structures. This should simplify the development of modeling approaches for these flows since molecular mixing and chemical reaction, which occur within the flame sheet, can be separated from the large-scale mixing process.     

Effects of 1064 nm laser on the structural and optical properties of nanostructured TiO2 thin film

TiO₂ thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO₂ thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO₂ thin film is amorphous and after laser exposure it became TiO₂ anatase structure. Atomic force microscopy of the crystalline TiO₂ thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm² there is an increase in the transmission and it decreases at the value of 38 MW/cm² and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO₂ thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process.     

Structural changes in tin oxide thin film with laser exposure

The effects of laser irradiation on the surface, structure and optical properties of SnO thin films deposited on glass substrates using electron beam evaporation, are investigated. The thin film samples are irradiated using fundamental beam at 1064 nm from Q-switched Nd:YAG pulsed laser with different power densities. Structural morphology of the film is investigated using XRD patterns and AFM image. Both XRD pattern and AFM image show increase in grain size of the film with increasing laser power density. Other optical phenomena, photoluminescence emission, transmission, refractive index determination and optical band gaps calculations are also carried out at various laser power densities. Results from all these investigations reveal expansion in grain size of the crystalline SnO thin film with increasing laser power density.     

MHD flow of nanofluids over an exponentially stretching sheet in a porous medium with convective boundary conditions

This article concentrates on the steady magnetohydrodynamic(MHD) flow of viscous nanofluid. The flow is caused by a permeable exponentially stretching surface. An incompressible fluid fills the porous space. A comparative study is made for the nanoparticles namely Copper(Cu), Silver(Ag), Alumina(Al2O3) and Titanium Oxide(TiO2). Water is treated as a base fluid. Convective type boundary conditions are employed in modeling the heat transfer process. The non-linear partial differential equations governing the flow are reduced to an ordinary differential equation by similarity transformations. The obtained equations are then solved for the development of series solutions. Convergence of the obtained series solutions is explicitly discussed. The effects of different parameters on the velocity and temperature profiles are shown and analyzed through graphs.     

A branch-and-bound algorithm for single-machine scheduling with batch delivery minimizing flow times and delivery costs

This paper addresses scheduling a set of jobs on a single machine for delivery in batches to customers or to other machines for further processing. The problem is a natural extension of minimizing the sum of flow times by considering the possibility of delivering jobs in batches and introducing batch delivery costs. The scheduling objective adopted is that of minimizing the sum of flow times and delivery costs. The extended problem arises in the context of coordination between machine scheduling and a distribution system in a supply chain network. Structural properties of the problem are investigated and used to devise a branch-and-bound solution scheme. Computational experiments show significant improvements over an existing dynamic programming algorithm.     

Two new proanthocyanidin trimers isolated from Cistus incanus L. demonstrate potent anti-inflammatory activity and selectivity to cyclooxygenase isoenzymes inhibition

Two new proanthocyanidin trimers have been isolated from Cistus incanus herb; gallocatechin-(4α→6)-gallocatechin-(4α→8)-gallocatechin (compound 1) and epigallocatechin-3-O-gallate-(4ß→8)-epigallocatechin-3-O-gallate-(4ß→8)-gallocatechin (compound 2). The structures were determined on the basis of 1D- and 2D-NMR (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-MS and by acid-catalysed degradation with phloroglucinol. A more abundant proanthocyanidin oligomer was also isolated, purified and its chemical constitution studied by ¹³C-NMR and phloroglucinol degradation. The mean molecular weight of the polymer was estimated to be about 7 to 8 flavan-3-ol-units with a ratio of procyanidin?:?prodelphinidin units at 1:5, some of which are derivatised by gallic acid. Water extract and higher oligomeric proanthocyanidin fractions of C. incanus significantly inhibited TPA-induced oedema when applied topically at doses of 0.5 and 1 mg/ear in mice. Furthermore, the extracts and the pure compounds inhibited COX-1 and COX-2 activities. In addition, compound 2 exhibited an IC₅₀ of 4.5 μM against COX-2 indicating its high selectivity towards COX-2.     

A comparative study on the performance of hybrid solar cells containing ZnSTe QDs in hole transporting layer and photoactive layer

In this paper, ZnSTe quantum dots-based hybrid solar cells (HSC) with two different device architectures have been investigated. The improved performance of the poly(3-hexylthiophene) (P3HT) and [6,6]phenyl C₇₁ butyric acid methyl ester (PC₇₁BM)-based bulk heterojunction (BHJ) solar cells by the incorporation of ZnSTe quantum dots (QDs) with an average size of 2.96 nm in PEDOT:PSS layer and active layer that have been demonstrated. Although the efficiency of both types of devices is almost the same, a close comparison reveals different reasons behind their improved performance. The device prepared with QDs in the HTL has shown reduced series resistance, increased shunt resistance, and improved mobility. On the other hand, QDs in the photoactive layer demonstrates increased photo-generation leading to improved efficiency.     

纳米多级孔分子筛：简短的综述

分子筛是一种三维微孔结构的硅铝酸盐晶体,具有灵活多变的骨架和组成、较高的物理和水热稳定性、无毒、高比表面积、离子可交换性以及很低的成本等特点,因而在油品精制、石油化学、农业、水和污水处理等众多领域中用作离子交换剂、催化剂和吸附剂。尽管分子筛的应用是基于其本身的微孔结构,但微孔也导致体积较大的反应物和产物分子的传质阻力高。通过制备纳米尺度和多级孔结构的分子筛等多种手段可克服常规分子筛所具有的传质限制。人们已经开发了多种方法制备了新型的分子筛材料,并考察了它们在各种催化反应和吸附反应中的性能。在反应体系中采用这种多级孔的纳米分子筛,有可能提高催化剂的使用寿命和催化性能,抑制积碳和失活。本综述概述了多级孔分子筛和纳米分子筛的高性能及其合成方法的最新进展,讨论了每个合成方法的优缺点,简述了纳米分子筛和二级孔结构分子筛的催化应用,并与常规分子筛进行了比较。     

A Series of Collaborations between Various Pharmaceutical Companies and Regulatory Authorities Concerning the Analysis of Biomolecules Using Capillary Electrophoresis: Additional Instruments/Buffer

An international project team (including members from US, Canada and UK) was formed from a number of interested biopharmaceutical companies and regulatory authorities to conduct a cross-organisation collaboration exercise. The results of the first comparison with eight different organisations that used instruments of the same equipment model, the same reagents, and the same methodology has been reported previously [1]. This report represents the addition of other instruments using a different run buffer. The relative migration times were different, as expected, prohibiting a direct comparison between companies. The within-organisation variability was low for both relative migration time (<0.34% RSD% for all companies save one) and the peak area (<5% RSD% for all companies save one) when measuring the purity of a representative IgG sample. The apparent molecular weight of bovine serum albumin was measured with good precision (less than 10% RSD% across all companies) to the theoretical value when all data is utilized (67.5 kDa compared to 66.4 kDa). For a representative IgG sample, the three main components, IgG Light Chain, IgG Non-glycosylated Heavy Chain, and IgG Heavy Chain, could not be separated, specifically the IgG Non-glycosylated Heavy Chain and IgG Heavy Chain. When the IgG Non-glycosylated Heavy Chain and IgG Heavy Chain were combined for all organisations, the fractional peak area for the IgG Light Chain and IgG Non-glycosylated Heavy Chain + IgG Heavy Chain peak also showed excellent agreement, with less than 7.5 and 3.5% RSD%, respectively. The value of this exercise is in demonstrating the reliability of CE for the determination of apparent size of biopharmaceutical proteins. This underpins the appropriate use of such CE data in support of regulatory submissions.