Developing an electro-thermal model to determine heat generation and thermal properties in a lithium-ion battery

Journal of Thermal Analysis and Calorimetry - Lithium-ion batteries should continuously be operated at the optimum temperature range $$\left( {15 \sim 40 \,^\circ C} \right)$$ for the best...     

Carbon–carbon coupling reactions catalyzed by supported Pd porphyrins

The tetrakis(4‐N‐methylpyridinium)porphyrinatopalladium(II) iodide, [Pd(TMPyP)]I₄, supported on Dowex 50WX8 and Amberlite IR‐120 ion‐exchange resins, was used as heterogeneous, recyclable and active catalyst for the Suzuki–Miyaura and Heck cross‐coupling reactions. These catalysts were applied to coupling of various aryl halides with phenylboronic acid and styrene in Suzuki and Heck reactions, respectively, and the corresponding products were obtained in excellent yields and short reaction times. The catalysts could be recovered easily by simple filtration and reused several times without significant loss of their catalytic activity. The catalysts were characterized by diffuse‐reflectance UV–visible spectroscopy and scanning electron microscopy, and their stability was confirmed by TGA. Copyright © 2014 John Wiley & Sons, Ltd.     

Conductive Biomaterials as Substrates for Neural Stem Cells Differentiation towards Neuronal Lineage Cells

The injuries and defects in the central nervous system are the causes of disability and death of an affected person. As of now, there are no clinically available methods to enhance neural structural regeneration and functional recovery of nerve injuries. Recently, some experimental studies claimed that the injuries in brain can be repaired by progenitor or neural stem cells located in the neurogenic sites of adult mammalian brain. Various attempts have been made to construct biomimetic physiological microenvironment for neural stem cells to control their ultimate fate. Conductive materials have been considered as one the best choices for nerve regeneration due to the capacity to mimic the microenvironment of stem cells and regulate the alignment, growth, and differentiation of neural stem cells. The review highlights the use of conductive biomaterials, e.g., polypyrrole, polyaniline, poly(3,4‐ethylenedioxythiophene), multi‐walled carbon nanotubes, single‐wall carbon nanotubes, graphene, and graphite oxide, for controlling the neural stem cells activities in terms of proliferation and neuronal differentiation. The effects of conductive biomaterials in axon elongation and synapse formation for optimal repair of central nervous system injuries are also discussed.     

Output-feedback formation control of wheeled mobile robots with actuators saturation compensation

Nonlinear Dynamics - This paper addresses output-feedback formation control of a group of wheeled mobile robots with saturating actuators. A virtual leader–follower strategy and a...     

Ultrasound promoted selective synthesis of 2-aryl-5,6-dihydro-4H-1,3-oxazines catalyzed by K-10 and KSF montmorillonite clays: A practical procedure under mild and solvent-free conditions

Montmorillonite K-10 and KSF were found to be highly efficient, environmentally friendly and recyclable heterogeneous catalysts for the selective synthesis of a variety of 2-aryl-5,6-dihydro-4H-1,3-oxazines from arylnitriles and 3-amino-1-propanol under ultrasound irradiation. This new methodology provides excellent yields in short reaction times (10–25 min). The reaction work-up is very simple and the catalysts can be easily separated from the reaction mixture and reused several times in subsequent reactions. This catalytic system also exhibits excellent chemoselectivity in the synthesis of mono-oxazines from dinitriles.     

Thermal analysis of high-index-contrast grating (HCG)-based VCSEL

A 3-D thermal analysis of 870 nm high-index-contrast grating (HCG)-based vertical cavity surface emitting laser (VCSEL) by using finite volume method (FVM) is presented in this paper. The HCG-based VCSEL is modeled by applying a steady-state 3-D heat dissipation model. Temperature distribution profile and thermal resistance (R_th) of the device are investigated by inserting the heat source value into the thermal simulation. Also, this analysis is performed for a conventional VCSEL operating at the same wavelength and under the same injected current as well as the same geometric sizes. The analysis shows that the maximum temperature inside the HCG-based VCSEL is lower than that inside the conventional VCSEL.     

Experimental investigation for enhanced ferrofluid heat transfer under magnetic field effect

This paper reports an experimental work on the convective heat transfer of ferrofluid flowing through a heated copper tube in the laminar regime in the presence of magnetic field. Significant enhancement on the heat transfer of ferrofluid by applying various orders of magnetic field is observed in this experiment. Also in this experiment, the effect of magnetic nanoparticles concentrations and magnet position have been investigated. The main reason for the enhancement of heat transfer coefficient could be caused due to remarkable changes in thermophysical properties of ferrofluid under the influence of applied magnetic field.     

Improvements of physical and mechanical properties of electron beam irradiation—crosslinked EVA foams

In this work, ethylene–vinyl acetate (EVA) copolymer foams were prepared and crosslinked by using high‐energy electron beam (e‐beam) radiation (10 MeV). The effect of parameters such as irradiation dose, the contents of foaming agent, radiation activator, and radiation sensitizer on improvement of physical and mechanical properties of the EVA foamed samples were investigated. The foams were obtained through a four‐step process of melt mixing, forming, crosslinking, and foaming. During the melt mixing process EVA was compounded with different amounts of azodicarbonamide (ADCA) as a blowing agent, zinc oxide (ZnO) as a radiation activator, and trimethylol propane‐trimethacrylate (TMPTMA) as a radiation sensitizer. The samples were compression molded into flat sheets at low temperature (110°C) and were then radiation‐crosslinked by 20–80 kGy e‐beam. Finally, the crosslinked samples were converted to foams by a high temperature (210°C) compression molding process. The foamed samples were analyzed in terms of gel content, density, compression molding set, tensile properties, and micro‐structural features. It was found that an increase in absorbed radiation dosage increases crosslink density, elasticity, percentage recovery, tensile strength, and compression properties of the EVA foams. Due to the increased recovery the percentage of compression set was reduced. Similarly increasing the TMPTMA content in the formulation increased the crosslink density and the resulting mechanical properties. Contrary to these findings, addition of ADCA led to the formation of extra gases which in turn reduced the crosslink density, and resulted in the deterioration of the mechanical properties and hence an increase in the compression set. However, addition of ZnO and TMPTMA led to the formation of smaller and more uniform cell size with improved mechanical properties. Copyright © 2008 John Wiley & Sons, Ltd.     

Microwave-assisted rapid and efficient deprotection and direct esterification and silylation of MOM and EOM ethers catalyzed by [Hmim][HSO4] as a Br?nsted acidic ionic liquid

Abstract  

1-Methylimidazolium hydrogensulfate, [Hmim][HSO₄], a Br?nsted acidic room temperature ionic liquid, is used as a catalyst and reaction medium for facile and eco-friendly deprotection of methoxymethyl (MOM) and ethoxymethyl (EOM) ethers to their corresponding alcohols under thermal conditions (Δ) and microwave irradiation (MW). Furthermore, one-pot interconversion to the respective acetates and trimethylsilyl (TMS) ethers was also achieved.     

H3PW12O40–[bmim][FeCl4]: A novel and green catalyst-medium system for microwave-promoted selective interconversion of alkoxymethyl ethers into their corresponding nitriles, bromides and iodides

In the present work, the catalytic activity of 12-tungstophosphoric acid immobilized on [bmim][FeCl₄] ionic liquid as a highly efficient and eco-friendly catalytic system for rapid and chemoselective direct conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides and iodides under microwave irradiation is reported. In these reactions, the products are obtained in high yields. The catalyst exhibited remarkable reactivity and was reused several times.