Colour control in fly ash as a combined function of particle size and chemical composition

This paper presents the results of an investigation on the combined effect of particle size and chemical composition on the colour of fly ash - a property that determines whether fly ash polymer composites can be engineered to have very light appearance satisfying the need for a wide range of commodity applications, particularly in the building material and computer housing industry. Four fly ash samples were collected from Tarong power plant Queensland, Australia, namely fly ash from first hopper (T59), classified fly ash from first hopper (T60), grinded and then classified fly ash from first hopper (T63) and fly ash from fourth hopper (T64). It was found that the particle size of T64 is smaller but still in the same order as T63. Colour measurement and chemical composition analysis of the different FA samples showed that there is a correlation between the particle size, chemical composition and colour of the fly ash. This information could be effectively used in fly ash recycling industry.     

Global oil depletion: A review of the evidence

Within the polarised and contentious debate over future oil supply a growing number of commentators are forecasting a near term peak and subsequent decline in production. But although liquid fuels form the foundation of modern industrial economies, the growing debate on ‘peak oil’ has relatively little influence on energy and climate policy. With this in mind, the UK Energy Research Centre (UKERC) has conducted an independent, thorough and systematic review of the evidence, with the aim of establishing the current state of knowledge, identifying key uncertainties and improving consensus. The study focuses upon the physical depletion of conventional oil in the period to 2030 and includes an in-depth literature review, analysis of industry databases and a detailed comparison of global supply forecasts. This Communication summarises the main findings of the UKERC study. A key conclusion is that a peak of conventional oil production before 2030 appears likely and there is a significant risk of a peak before 2020.     

Effect of Hot-Pressing on the Bi─Pb─Sr─Ca─Cu─O System

Uniaxial hot-pressing has been used to improve the relative density and preferred gain orientation of the nearly pure (Bi, Pb)₂Sr₂Ca₂Cu₃O_10-y (2223) phase in the Bi-Pb-Sr-Ca-Cu-O system. Samples were prepared by freeze-drying, calcining, and hot-pressing the powders at 650° to 840°C at 50 and 200 MPa for 2 h. The hot-pressed samples showed a high degree of grain alignment and increased density up to 99% of theoretical. At 200 MPa, the 2223 phase was partially destroyed during hot-pressing, probably because of the weak bonding between the Bi─O₂ layers. However, the 2223 phase and superconductivity were recovered with subsequent annealing. The critical current density ( J _c) was improved 10-fold over that of sintered samples through this technique, with the highest J _c being 2100 A°Cm⁻² at 77.3 K and zero field. The hot-pressed samples also showed significant improvements in the J _c as a function of applied magnetic field. The J _c of a hot-pressed and postannealed sample at 0.2 T and 77.3 K was 2 orders of magnitude greater than that of a sintered sample.     

Soluble proteins modified with acetaldehyde and malondialdehyde are immunogenic in the absence of adjuvant

Recent studies have shown that the alcohol metabolites malondialdehyde and acetaldehyde can combine to form a stable adduct (MAA) on proteins. This adduct has been detected in the livers of rats chronically consuming ethanol, and serum antibodies to MAA have been observed at significantly higher concentrations in ethanol-fed when compared with pair-fed or chow-fed control rats. More recently, preliminary studies have strongly suggested that the MAA adduct is capable of stimulating antibody responses to soluble proteins in the absence of adjuvants. The antibodies produced recognize either the MAA epitope or the carrier protein itself. Therefore, it was the purpose of this study to examine the potential immunogenicity of MAA-modified exogenous proteins in the absence of adjuvants. Balb/c mice were immunized in the presence or absence of adjuvant with different concentrations of unmodified or MAA-modified proteins. The antibody response to both the MAA epitope and unmodified protein epitopes were determined by ELISA. In the absence of adjuvant, significant antibody responses were induced to both the MAA epitope and nonmodified protein epitopes. Smaller immunizing doses of MAA-protein conjugate favored the production of antibodies to nonmodified proteins, whereas larger doses induced a strong anti-MAA response. In studies to begin determining a mechanism for the specificity of the response in the absence of adjuvants, peritoneal macrophages were found to bind and degrade MAA-adducted proteins through the use of a scavenger receptor. This indicated that MAA-adducted proteins may be specifically taken up and epitopes presented to the humoral immune system in the absence of adjuvants. Importantly, these are the first data showing that an alcohol-related metabolite can induce an antibody response in the absence of adjuvant and suggesting a mechanism by which antibody to the MAA adduct or its carrier (exogenous or endogenous) proteins may be generated in vivo.     

Equilibration kinetics of (La,Sr)MnO3

The present work reports isothermal changes of oxygen non-stoichiometry for the perovskite-type electrode material (La_0.8Sr_0.2)MnO₃ in the temperature range 945–1255 K. A thermogravimetric method was used to monitor the rate of the gas/solid equilibration. For equilibration degrees larger than 0.5, the equilibration kinetic data can be described by a diffusion equation. The determined chemical diffusion coefficient depends essentially on the oxygen partial pressure. Its temperature dependence can be expressed by the following expressions at low and high p(O₂), respectively:

A global model for rapid thermal processors

A simple model for the components that make up a rapid thermal processing system is given. These components are the furnace, the pyrometer used to measure temperature, and the control system that utilizes the pyrometer measurement to control the power to the lamps. The models for each of the components are integrated in a numerical code to give a computer simulation of the complete furnace operation. The simulation can be used to investigate the interaction of the furnace, temperature-sensing technique, and the control system. Therefore, the interplay of heat transfer (furnace) properties, optical (pyrometer) parameters, and control gains can be studied. The objective is to define variability in wafer temperature as process parameters change. The following three applications of the model are included: (1) a simulation of open-loop operation; (2) a simulation of the ramp up and subsequent operation with a step change in wafer optical properties; and (3) a simulation of the rapid thermal chemical vapor deposition of polysilicon on silicon oxide which demonstrates the applicability model for actual processes. A technique for correction of pyrometer output to improve temperature control is also presented     

Reaction Sequence and Structural Changes in Cordierite Refractories

In order to determine temperatures of mullitization and cordierite formation, to outline the reaction sequence by which cordierite is formed, and to determine the effects of prolonged heating on cordierite development and structure, two separate series of experiments were performed. Specimens were fired for 1 hour at temperature intervals between 1000° and 1360°C. and analyzed for cordierite and mullite by X-ray diffraction for the purpose of correlation with differential thermal analyses. Specimens were also fired at four different temperatures for periods of 1 to 192 hours and analyzed by X-ray diffraction for cordierite content and structural changes. Mullitization occurred by exothermic reaction at 1267°C. Endothermic peaks at 1238° and 1330°C. are attributed to the formation of cordierite. Prolonged-heating studies indicated that a progressive change takes place in cordierite by which a metastable hexagonal form is converted with time, through all intermediate stages, to the orthorhombic form which is stable at that temperature. Temperature was apparently the critical factor in cordierite development, time being of greater importance at lower temperatures.