LES of unsteady vortex aerodynamics in complex geometry gas-turbine fuel injectors

LES of unsteady vortex aerodynamics in complex geometry gas-turbine fuel injector

Toward a Control Oriented Model of Xerographic Marking Engines

This paper presents some preliminary results from a research collaboration concerning the modeling and control of color xerography. In this first communication of our work, we describe our efforts to develop a model for a monochrome marking engine. We adopt the technique of principal component analysis for choice of output coordinates and demonstrate preliminary experimental evidence suggesting that this procedure yields accuracy in data reconstruction superior to present industry practice. Preliminary analysis of the experimental evidence suggests that the process has a nonlinear component that we seek to model using a mixture of physical and empirical insight

Reducing the environmental impacts of desalination reject brine using modified Solvay process based on calcium oxide

This is the final version. Available from MDPI via the DOI in this record. : In this research, the influence of a variety of operational factors such as the temperature of the reaction, gas flow rate, concentration of NaCl, and the amount of Ca(OH)₂ for reducing the environmental impacts of desalination reject brine using the calcium oxide‐based modified Solvay process were investigated. For this purpose, response surface modeling (RSM) and central compo‐ site design (CCD) were applied. The significance of these factors and their interactions was assessed using an analysis of variance (ANOVA) technique with a 95% degree of certainty (p < 0.05). Optimal conditions for this process included: a temperature of 10 °C, a Ca(OH)₂/NaCl concentration ratio of 0.36, and a gas flow rate of 800 mL/min. Under these conditions, the maximum sodium removal efficiency from the synthetic sodium chloride solution was 53.51%. Subsequently, by employing the real brine rejected from the desalination unit with a 63 g/L salinity level under optimal conditions, the removal rate of sodium up to 43% was achieved. To investigate the process’s kinetics of Na elimination, three different kinds of kinetics models were applied from zero to second order. R squared values of 0.9101, 0.915, and 0.9141 were obtained in this investigation for zero‐, first‐, and second‐degree kinetic models, respectively, when synthetic reject saline reacted. In contrast, accord‐ ing to R squared’s results with utilizing real rejected brine, the results for the model of kinetics were: R squared = 0.9115, 0.9324, and 0.9532, correspondingly. As a result, the elimination of sodium from real reject brine is consistent with the second‐order kinetic model. According to the findings, the calcium oxide‐based modified Solvay method offers a great deal of promise for desalination of brine rejected from desalination units and reducing their environmental impacts. The primary benefit of this technology is producing a usable solid product (sodium bicarbonate) from sodium chloride in the brine solution

Control of crystallinity of vinylene-linked two-dimensional conjugated polymers by rational monomer design

The interest in two-dimensional conjugated polymers (2D CPs) has increased significantly in recent years. In particular, vinylene-linked 2D CPs with fully in-plane sp2-carbon-conjugated structures, high thermal and chemical stability, have become the focus of attention. Although the Horner-Wadsworth-Emmons (HWE) reaction has been recently demonstrated in synthesizing vinylene-linked 2D CPs, it remains largely unexplored due to the challenge in synthesis. In this work, we reveal the control of crystallinity of 2D CPs during the solvothermal synthesis of 2D-poly(phenylene-quinoxaline-vinylene)s (2D-PPQVs) and 2D-poly(phenylene-vinylene)s through the HWE polycondensation. The employment of fluorinated phosphonates and rigid aldehyde building blocks is demonstrated as crucial factors in enhancing the crystallinity of the obtained 2D CPs. Density functional theory (DFT) calculations reveal the critical role of the fluorinated phosphonate in enhancing the reversibility of the (semi)reversible C−C single bond formation

Fully sp²‐carbon‐linked crystalline two‐dimensional conjugated polymers: insight into 2D poly(phenylenecyanovinylene) formation and their optoelectronic properties

Cyano‐substituted polyphenylene vinylenes (PPVs) have been in the focus of research for several decades due to their interesting optoelectronic properties and potential applications in organic electronics. With the advent of organic two‐dimensional (2D) crystals, the question arose how the chemical and optoelectronic advantages of PPVs evolve in 2D compared to their linear counterparts. In this work, we present the efficent synthesis of two novel 2D fully sp²‐carbon‐linked crystalline PPVs and investigate the essentiality of inorganic bases for their catalytic formation. Notably, among all bases screened, cesium carbonate (Cs₂CO₃) plays a crucial role and enables reversibility in the first step with subsequent structure locking by formation of a C=C double bond to maintain crystallinity, which is supported by density functional theory (DFT) calculation. We propose a quantifiable energy diagram of a “quasi‐reversible reaction” which allows to identify further suitable C‐C bond formation reactions for 2D polymerizations. Moreover, we delineate the narrowing of the HOMO‐LUMO gap by expanding conjugation into two dimensions. To enable environmentally benign processing, we further perform the post‐modification of 2D PPVs, which renders stable dispersions in the aqueous phase

Electron transport through self-assembled monolayers of tripeptides

We report how the electron transport through a solid-state metal/Gly-Gly-His tripeptide (GGH) monolayer/metal junction and the metal/GGH work function are modified by the GGH complexation with Cu2+ ions. Conducting AFM is used to measure the current-voltage histograms. The work function is characterized by combining macroscopic Kelvin probe and Kelvin probe force microscopy at the nanoscale. We observe that the Cu2+ ions complexation with the GGH monolayer is highly dependent on the molecular surface density and results in opposite trends. In the case of a high density monolayer the conformational changes are hindered by the proximity of the neighboring peptides, hence forming an insulating layer in response to copper-complexation. Whereas the slightly lower density monolayers allow for the conformational change to a looped peptide wrapping the Cu-ion, which results in a more conductive monolayer. Copper-ion complexation to the high- and low-density monolayers systematically induces an increase of the work functions. Copper-ion complexation to the low-density monolayer induces an increase of electron transport efficiency, while the copper-ion complexation to the high-density monolayer results in a slight decrease of electron transport. Both of the observed trends are in agreement with first-principle calculations. Complexed copper to low density GGH-monolayer induces a new gap state slightly above the Au Fermi energy that is absent in the high density monolayer.Comment: Full paper with supporting informatio

Performance enhancement of specific adsorbents for hardness reduction of drinking water and groundwater

This is the final version. Available from MDPI via the DOI in this record. One of the most advantageous methods for lowering water hardness is the use of low-cost adsorbents. In this research, the effectiveness of natural zeolite (clinoptilolite type), activated carbon, and activated alumina was evaluated. These adsorbents were sequentially modified by NaCl, HCl, and NaCl-HCL to improve their ability to adsorb. The contact time and the amount of adsorbent used in the adsorption process were investigated experimentally to determine their effects. The results indicated that the best contact time for hardness reduction was 90 min, and the best concentrations of adsorbents in drinking water for zeolite, activated carbon, and activated alumina were 40, 60, and 60 g/L, respectively. In addition, for groundwater, these figures were 60, 40, and 40 g/L, respectively. The greatest possible decreases in total hardness under the best conditions by natural zeolite, activated carbon, and activated alumina adsorbents were 93.07%, 30.76%, and 56.92%, respectively, for drinking water and 59.23%, 15.67 %, and 39.72% for groundwater. According to the results obtained from experiments, NaCl-modified zeolite, natural zeolite, and NaCl-HCl-modified activated carbon performed better in terms of parameter reduction. The equilibrium data were well fitted by the Langmuir isotherm model, whereas the kinetic data for the adsorption process were consistent with the pseudo-second-order model. The equilibrium study of the adsorption process by the Morris–Weber model revealed that both chemical and physical adsorption are involved.Bushehr Water & WasteWater Company (Iran

Visual change detection on tunnel linings

We describe an automated system for detecting, localising, clustering and ranking visual changes on tunnel surfaces. The system is designed to provide assistance to expert human inspectors carrying out structural health monitoring and maintenance on ageing tunnel networks. A three-dimensional tunnel surface model is first recovered from a set of reference images using Structure from Motion techniques. New images are localised accurately within the model and changes are detected versus the reference images and model geometry. We formulate the problem of detecting changes probabilistically and evaluate the use of different feature maps and a novel geometric prior to achieve invariance to noise and nuisance sources such as parallax and lighting changes. A clustering and ranking method is proposed which efficiently presents detected changes and further improves the inspection efficiency. System performance is assessed on a real data set collected using a low-cost prototype capture device and labelled with ground truth. Results demonstrate that our system is a step towards higher frequency visual inspection at a reduced cost.The authors gratefully acknowledge the support by Toshiba Research Europe.This is the accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s00138-014-0648-8

Use of Biliary Organoids in Cholestasis Research.

Cholangiocytes play a crucial role in the pathophysiology of cholestasis. However, research on human cholangiocytes has been restricted by challenges in long-term propagation and large-scale expansion of primary biliary epithelium. The advent of organoid technology has overcome this limitation allowing long-term culture of a variety of epithelia from multiple organs. Here, we describe two methods for growing human cholangiocytes in organoid format. The first applies to the generation of intrahepatic bile ducts using human induced pluripotent stem cells using a protocol of differentiation that recapitulates physiological bile duct development. The second method allows the propagation of primary biliary epithelium from the extrahepatic ducts or gallbladder. Both protocols result in large numbers of cholangiocyte organoids expressing biliary markers and maintaining key cholangiocyte functions