Characterisation of thermo-mechanical properties of MgO–Al2O3–SiO2 glass ceramic with different heat treatment temperatures

The effects of heat treatment temperature on crystallisation behaviour, precipitated phases and thermo-mechanical properties of some MgO–Al₂O₃–SiO₂ (MAS) glass-ceramics were investigated. Crystallisation behaviour of MgO–Al₂O₃–SiO₂ glasses in the presence of TiO₂ as a nucleation agent was studied. The crystalline phases present in the heat treated samples were identified by X-ray diffraction (XRD). It was observed from XRD studies that magnesium aluminium titanate initially precipitated and when the heat treatment temperature was increased to 1140 °C, depending on the thermal history, either magnesium silicate, aluminium titanate and quartz or magnesium aluminium titanate, magnesium aluminate and quartz were precipitated. SEM observation revealed that the heat treatment led to phase separation of droplet-shaped crystals before the needle-shaped crystals formed at 1140 °C. The effect of annealing temperature on the density and mechanical properties of these glass-ceramic were characterised by nanoindentation and the results revealed a significant increase in hardness of the fully crystallised system.     

Effect of bio‐oil and epoxidized linseed oil on physical,mechanical, and biological properties of treated wood

In this article, the effects of bio‐oil and epoxidized linseed oil (ELO) on water absorption, tangential swelling, decay and insect resistance, thermo‐gravimetric analysis, and mechanical properties of treated wood samples were studied. The bio‐oil used in this article was by‐product of ThermoWood thermal modification process. Linseed oil and hydrogen peroxide were used to prepare ELO. The results indicated that the samples treated with bio‐oil had lower water absorption than that of the control group. The second treatment with ELO significantly reduced further the water absorption. The decay resistance of treated wood samples with 20% of bio‐oil against brown (Coniophora puteana) and white rot (Trametes versicolor) fungi was very high. According to the insect test results, increasing bio‐oil concentration from 10% to 20% significantly decreased surviving rate of Hylotrupes bajulus. Thermo‐gravimetric analysis showed that all treated samples had higher initial deterioration temperature than that of the control group. Regarding the wood strength, the impregnated bio‐oil generally reduced the mechanical properties of wood except modulus of elasticity (MOE). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1562–1569, 2013     

Effects of Sb and Nb dopants on electrical and microstructural properties of low-voltage varistor ceramics based on SnO2

It is shown that an addition of Sb₂O₅ or Nb₂O₅ (0.05–0.15?mol%) to the system SnO₂–CoO–Cr₂O₃–Bi₂O₃ leads to the enhancement of grain growth. This effect is associated with the presence of the liquid Bi-phase in ceramics during sintering. The obtained ceramics possess non-linear current-voltage characteristics and can be used for preparing low voltage varistors. The non-linearity coefficient α reaches 22 and the characteristic electric field 692?V/cm for Nb-doped materials and 11 and 421?V/cm respectively for Sb-doped ceramics materials. The results of dc and ac electrical measurements, as well as scanning electron microscopy are presented and discussed in terms of the known barrier model for varistors.     

Outlier detection in UV/Vis spectrophotometric data

UV/Vis spectrophotometers have been used to monitor water quality since the early 2000s. Calibration of these devices requires sampling campaigns to elaborate relations between recorded spectra and measured concentrations. In order to build robust calibration data sets, several spectra must be recorded per sample. This study compares two approaches – principal component analysis and data depth theory – to identify outliers and select the most representative spectrum (MRS) among the repetitively recorded spectra. Detection of samples that contain outliers is consistent between the methods in more than 70% of the samples. Identification of spectra as outliers is consistent in more than 95% of the cases. The identification of MRS differs depending on the approach used. In their current form, both of the proposed approaches can be used for outlier detection and identification. Further studies are suggested to combine the methods and develop an automated ranking and sorting system.     

Effects of concreteness-abstractness and anxiety on intellectual and motor performance.

Administered O. J. Harvey's "This I Believe" Test to undergraduates. 55 Ss were selected with concrete belief systems and 29 with abstract systems. Ss then played the role of arguing against their own stand on an ego-involving issue which was scored for 5 attributes: number to topics discussed, number of approaches utilized in the arguments, openness to negative evaluation, ethnocentrism, and absolutism. Ss also completed the WAIS Digit-Symbol Substitution test, a vocabulary test, an arithmetic test, the A-State scale of the State-Trait Anxiety Inventory. On the basis of the anxiety measure, Ss were divided into "high" and "low" anxiety groups, and a 2-way analysis of variance (Concreteness-Abstractness * Anxiety) was run for each of the 8 dependent variables. Anxiety exercised a significant main effect on none of the 8 dependent variables, while concreteness-abstractness significantly affected 5. The interaction of these 2 variables, while in the anticipated direction in all instances, significantly affected performance only on the vocabulary measure. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On supernode transformation with minimized total running time

With the objective of minimizing the total execution time of a parallel program on a distributed memory parallel computer, this paper discusses how to find an optimal supernode size and optimal supernode relative side lengths of a supernode transformation (also known as tiling). We identify three parameters of supernode transformation: supernode size, relative side lengths, and cutting hyperplane directions. For algorithms with perfectly nested loops and uniform dependencies, for sufficiently large supernodes and number of processors, and for the case where multiple supernodes are mapped to a single processor, we give an order n polynomial whose real positive roots include the optimal supernode size. For two special cases, 1) two-dimensional algorithm problems and 2) n-dimensional algorithm problems, where the communication cost is dominated by the startup penalty and, therefore, can be approximated by a constant, we give a closed form expression for the optimal supernode size, which is independent of the supernode relative side lengths and cutting hyperplanes. For the case where the algorithm iteration index space and the supernodes are hyperrectangular, we give closed form expressions for the optimal supernode relative side lengths. Our experiment shows a good match of the closed form expressions with experimental data     

Nonlinear transmission and excited-state absorption in fluorene derivatives

The nonlinear transmission and the excited-state absorption spectra of three fluorene derivatives exhibiting large two-photon absorptivity were measured by the third harmonic of a picosecond Nd:YAG laser. We analyzed their capability for exhibiting stimulated emission in polar solvents and found that asymmetrical fluorene compounds with a diphenylamino substituent exhibited large Stokes shifts (approximately 8000 cm(-1)), high quantum yields (approximately 0.9-1.0), and no optical gain over their entire fluorescence spectral region. In contrast, a symmetrical fluorene derivative with vinylphenylbenzothiazole substituents in positions 2 and 7 underwent lasing under one-photon excitation by use of picosecond pulsed irradiation.     

Effects of turpentine and gasoline-like fuel obtained from waste lubrication oil on engine performance and exhaust emission

In this study, an experimental investigation was carried out to determine the effects of gasoline-like fuel (GLF), and its blends with turpentine with ratios of 10%, 20%, and 30% on the performance and emission characteristics of a gasoline engine. The GLF was obtained from waste lubrication engine oil by the method of pyrolitic distillation. Characteristics of the pure GLF and its blends were tested. A series of engine performance and emission tests were conducted using the fuel samples in the test engine. Performance parameters for each test were calculated utilizing measurement values of force exerted on the crank shaft, rate of air and fuel mass flow to the engine and engine speed. Effects of the fuels on the performance parameters, exhaust gas temperature, and emissions of NOx, CO, CO₂, and HC were discussed. The results indicated that torque, brake mean effective pressure and thermal efficiency increased but brake specific fuel consumption decreased with increasing amount of turpentine in the GLF sample. The main effect of 10%, 20% and 30% turpentine additions to GLF on pollutant formation was that the NOx ratio increased, whereas that of CO decreased.     

Phenolation of wood using oxalic acid as a catalyst: Effects of temperature and hydrochloric acid addition

Birch wood meal has been phenolated in the presence of oxalic acid alone or its mixture with hydrochloric acid (HCl) at various temperatures ranging from 150 to 250°C under high pressure. The effects of high temperature, high pressure, and the addition of HCl in conjunction with oxalic acid on the amounts of wood residue and combined phenol have been investigated. In the case of the oxalic acid-catalyzed process, by increasing reaction temperature from 180 to 250°C, the amounts of wood residue could be considerably reduced, but the amount of combined phenol decreased. In comparison to a noncatalyzed process in the absence of water, the catalyzed one offered a relatively lower amount of wood residue and a higher amount of combined phenol. However, compared to a noncatalyzed process with water, particularly at a high temperature of 250°C, the catalyzed process gave significantly larger amounts of wood residue. In addition, with a small addition of HCl to an oxalic acid catalyzed system, the amount of wood residue was remarkably reduced compared to that of oxalic acid alone, and the amount of combined phenol could be increased significantly. Furthermore, the mechanical properties of the moldings prepared from the phenolated wood were sufficiently improved by the addition of a small amount of HCl to the oxalic acid-catalyzed system. © 1996 John Wiley & Sons, Inc.