Materials Literature
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The synthesis of coumarins (2H-benzopyran-2-ones) via Knoevenagel condensation over a recoverable, inexpensive solid base catalyst, calcined Mg–Al hydrotalcite, is reported for the first time. This method produces substituted coumarins in very high yields (>85%) and selectivities (ca. 100%) when aromatic hydroxy aldeh…
This paper presents a review of leakage current (Lc) measurements on nonceramic insulators and material samples. It is divided into two parts: First, the field investigations of LC, include a development of LC measuring systems and how the on-line LC measurements correlate to the insulator performance as well as to th…
Ni ‐ YSZ anodes with a new microstructure for solid oxide fuel cells were successfully prepared from NiO ‐ YSZ composite powder. The composite powder consisting of fine YSZ particles dispersed on the surface of NiO particles was synthesized by spray pyrolysis. The anodic polarization for Ni ‐ YSZ cermet in which few s…
ABSTRACT Extruded instant corn flour (EICF) samples with hydrocolloids (gums), such as gum arabic, carboxymethylcellulose (CMC), guar and xanthan and with different concentrations of lime (0.1, 0.2 and 0.3% w/w) were prepared by extrusion. The gums were added before or after thermal processing. The dehydration process…
Elastic constants of Ti50Ni30Cu20 alloy prior to the martensitic transformation B2 → B19 was measured for the first time by using the rectangular parallelepiped resonance method. The softening in both shear modulus ć and c44 was found with approaching transformation temperature. As a result of soft c 44, the anisotrop…
Reaction of 4,5-bis(methylsulfanyl)-1,3-dithiole-2-thione 1 with diiodine or iodine monobromide in CH2Cl2 resulted in the formation of molecular charge-transfer complexes 1·I2 and 1·IBr respectively. Both complexes have been characterised crystallographically and contain a linear S–I–X (X = I or Br) moiety with the su…
Nanocrystalline zirconium dioxide particles have been produced by means of thermal decomposition of a liquid metal organic precursor in a flow reactor system. X-Ray diffraction patterns show that the powder consists of a mixture of the monoclinic and tetragonal phase and that the phase fractions depend on the experime…
The present work focuses on a capillary rise technique, referred to here as column wicking, for determining contact angles on wood particles. The liquid front rise versus time for different probe liquids has been measured for extracted and non-extracted spruce wood particles packed into glass columns. Wood is a porous…
A method of anodizing valve metals in glycerin‐based solutions at elevated temperature to produce nonporous oxide films is presented. The thickness is not limited by the anodizing voltage, but by the amount of time at voltage or, more accurately, by the total amount of ionic current passed through the film. The import…
During the authors' efforts to stabilize contaminated ashes in the U.S. Department of Energy's (DOE's) complex by a novel chemically bonded phosphate ceramic, they formulated a high strength concrete made of benign ashes (such as fly ash and coal bottom ash) that may be useful for specialized applications in the const…
A novel pore tailoring method is proposed by which the pore-opening sizes of MCM-41 materials can be finely tuned without significant loss in pore volume and surface area.
Nanoparticles of Pt, Pd, Ag and Au supported on α-Al 2 O 3 have been synthesized by the combustion method for the first time and characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Catalytic activities of these nanosized materials have been investigated. For the C…
Nanocrystalline semiconductors AgGaS2 and AgInS2 with particle sizes ranging from 5 to 12 nm are prepared by a solvothermal reaction in the temperature range 180–230 °C.
An analytical solution is found using the Laplace transform to describe the very fast transient overvoltage (VFTO) in the gas insulated switchgear (GIS) connected directly to a transformer. The oscillation frequencies, and other properties, are explicitly given in terms of system parameters. The magnitude of VFTO at t…
We present the results of high resolution neutron powder diffraction studies of the NZP phases LiTi2(PO4)3 (LiTP) and KTi2(PO4)3 (KTP). The thermal expansion coefficients for both materials are reported and compared to those of NaTi2(PO4)3. αa for LiTP is found to decrease from 0.75 to 0.27 × 10–6 °C–1 between 20 and…
The present paper proposes a model of relaxor ferroelectrics. which describes the polarization response of these materials in terms of vibration of the interphase boundary between the polar regions and nonpolar matrix. The model is formulated and is applied to explain various features of the polarization response of a…
Escherichia coli signal peptidase (SPase) and E. coli UmuD protease are members of an evolutionary clan of serine proteases that apparently utilize a serine-lysine catalytic dyad mechanism. Recently, the crystallographic structure of a SPase inhibitor complex was solved elucidating the catalytic residues and the subst…
Fenbufen is an analgesic, antipyretic and anti-inflammatory drug that is characterized by poor water solubility, a defect increased by very low wettability. Poor water solubility, particularly at low pH, could decrease absorption in the upper part of the gastrointestinal tract, which would be inconvenient for good bio…
Abstract A model is developed in this work for predicting the bubble size distribution in polyurethane foams generated by using water as a chemical blowing agent. The model combines equations of energy balance, kinetics of the reactions of isocyanate with water and polyol, and nucleation and growth of CO 2 bubbles. It…
Henry reactions have been performed for the first time with suitably activated Mg–Al hydrotalcite as catalyst in quantitative yields in the liquid phase under mild reaction conditions and with low reaction times. Exclusive synthesis of β-nitroalkanols (3) is realised by the compatible basic Brönsted hydroxy sites of t…