Structural and Piezoelectric Properties of (Na1−xKx)NbO3 Platelets and Their Application for Piezoelectric Nanogenerator

(Na_1?xK_x)NbO₃ (NKN) platelets synthesized at 600°C for 12 h have an Amm2 orthorhombic structure. However, the structure of NKN platelets synthesized at 500°C is a mixture of R3m rhombohedral and Amm2 orthorhombic structures. The formation of a rhombohedral structure is attributed to the presence of OH^? and H₂O defects in the NKN platelets. The piezoelectric strain constant (d₃₃) of NKN platelets synthesized at 600°C for 12 h is 100 pmV^?1, whereas that of NKN platelets synthesized at 500°C is lesser (50 pmV^?1) due to the presence of these defects. Piezoelectric nanogenerators (PNGs) are fabricated using composites consisting of NKN platelets and polydimethylsiloxane. A large output voltage of 25 V and output current of 2.7 μA were obtained for the PNG with NKN platelets synthesized at 600°C for 6 h. This PNG shows a high output electrical energy of 3.0 μW at an external load of 5.1 MΩ.     

Data‐driven mathematical modeling and global optimization framework for entire petrochemical planning operations

In this work we develop a novel modeling and global optimization‐based planning formulation, which predicts product yields and properties for all of the production units within a highly integrated refinery‐petrochemical complex. Distillation is modeled using swing‐cut theory, while data‐based nonlinear models are developed for other processing units. The parameters of the postulated models are globally optimized based on a large data set of daily production. Property indices in blending units are linearly additive and they are calculated on a weight or volume basis. Binary variables are introduced to denote unit and operation modes selection. The planning model is a large‐scale non‐convex mixed integer nonlinear optimization model, which is solved to ε‐global optimality. Computational results for multiple case studies indicate that we achieve a significant profit increase (37–65%) using the proposed data‐driven global optimization framework. Finally, a user‐friendly interface is presented which enables automated updating of demand, specification, and cost parameters. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3020–3040, 2016     

Effect of TeO2 on Near‐Infrared Emission from Bismuth Centers in Borogermanate Glasses

Bi‐doped xTeO₂–(60?x)GeO₂–15B₂O₃–20MgO–5Al₂O₃ glasses were prepared by the conventional melt‐quenching method and their absorption and fluorescence spectra were characterized. Broadband near‐infrared (NIR) emission from Bi centers centered around 1240 nm with a full width at half maximum (FWHM) of 250 nm was observed, and the position of the emission peak strongly depends on the excitation wavelength. Increasing TeO₂ concentration results in the strong coloration of the glass, leading to the reduction and finally, complete quenching of the NIR emission. Based on Raman, X‐ray photoelectron spectroscopy and transmission microscopy observation, the coloration of the glass at high TeO₂ concentration can be ascribed to the precipitation of elemental Te nanoparticles of around 3–8 nm, which effectively suppresses the NIR emission by reabsorption. The precipitation of Te nanoparticles in an oxide glass may find novel applications in photonics and relevant fields.     

High porosity glass foams from waste glass and compound blowing agent

The foaming behavior of waste glass green spheres mixed with carbonate was investigated at the temperatures of 680–800 °C. Effects of carbonate on the foaming process, microstructures and properties of the obtained glass foams were evaluated. Both the organic compounds and carbonate act as blowing agents during the foaming process. The results show that the carbonate effectively promotes the foaming process in the temperature range of 680–800 °C. The obtained glass foams show uniform microstructure, with bulk density, porosity and compressive strength values of 0.117–0.209 g/cm³, 91.7–95.4 % and 0.52–3.93 MPa, respectively. The high porosity glass foams have potential applications in many areas such as thermal insulation materials and sound absorption materials.     

Adiponectin Induces Oncostatin M Expression in Osteoblasts through the PI3K/Akt Signaling Pathway

Rheumatoid arthritis (RA), a common autoimmune disorder, is associated with a chronic inflammatory response and unbalanced bone metabolism within the articular microenvironment. Adiponectin, an adipokine secreted by adipocytes, is involved in multiple functions, including lipid metabolism and pro-inflammatory activity. However, the mechanism of adiponectin performance within arthritic inflammation remains unclear. In this study, we observed the effect of adiponectin on the expression of oncostatin M (OSM), a pro-inflammatory cytokine, in human osteoblastic cells. Pretreatment of cells with inhibitors of phosphatidylinositol 3-kinase (PI3K), Akt, and nuclear factor (NF)-κB reduced the adiponectin-induced OSM expression in osteoblasts. Stimulation of the cells with adiponectin increased phosphorylation of PI3K, Akt, and p65. Adiponectin treatment of osteoblasts increased OSM-luciferase activity and p65 binding to NF-κB on the OSM promoter. Our results indicate that adiponectin increased OSM expression via the PI3K, Akt, and NF-κB signaling pathways in osteoblastic cells, suggesting that adiponectin is a novel target for arthritis treatment.     

Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.     

Dehydration of <Emphasis Type="SmallCaps">d</Emphasis>-xylose over SiO<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst: Perspective on the pathways for condensed products

This work addresses the kinetic mechanism for the dehydration of D-xylose over the SiO₂-Al₂O₃ solid catalyst, where the formation of condensed products is included in addition to the production of furfural and its decomposition. The kinetic modeling and parametric sensitivity show that the isomerization of D-xylose takes place in the early stages of the reaction, followed by the dehydration of isomers. Accordingly, the homogeneous polymerization of isomers is found to be dominant. The developed model is used to evaluate the effects of operating conditions on the catalytic performance; high temperature and D-xylose concentration guarantee high furfural yield.     

V-promoted Ni/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst for synthetic natural gas (SNG) production: Catalyst preparation methodologies

The effect of preparation method on the catalytic performance of V-promoted Ni/Al₂O₃ catalysts for synthetic natural gas (SNG) production via CO methanation has been investigated. The Ni-V/Al₂O₃ catalysts were prepared by co-impregnation (CI) method, deposition precipitation (DP) method as well as two sequential impregnation (SI) methods with different impregnation sequence. Among the prepared catalysts, the one prepared by CI method exhibited the best catalytic performance due to its largest H₂ uptake and highest metallic Ni dispersion. In a 91h-lifetime test, this catalyst showed high stability at high temperature and weight hourly space velocity. This work demonstrates that the catalytic performance of the V-promoted Ni/Al₂O₃ catalysts can be improved by carefully controlling the preparation method/conditions.