Experimental study of splash generation in a flash smelting furnace

A survey of previous studies of splash formation in metallurgical vessels revealed that little information is available to characterize and describe the processes involved in splash formation. An experimental study of splash formation by top submerged gas injection was carried out in the settler region of the nickel flash smelting furnace at the Kalgoorlie Nickel Smelter (KNS) both to obtain some visualization of the splash mechanisms that occur on a plant scale and to measure the amount of splash being formed. Video images taken of the splashing showed that large sheets of melt were formed by the escaping gas and subsequently thinned into ligaments which then broke up into large splash drops. The video could only resolve a minimum size of 2 cm. The large splash drops visible on video have an initial velocity between 1 and 2 m/s, are unstable, and fall back into the bath after traveling a short distance. The analysis identified two major splash forming mechanisms. First, the gas injected resulted in the bulk movement of the melt to form a cavity and large sheets of melts being thrown around the point of injection. The area affected by this splash mechanism can be predicted successfully by using an energy balance between the removal of the melt in the cavity and the energy of the gas being injected. Second, the slag free surface within the cavity is highly unstable, and through the Kelvin-Helmholtz instability mechanism, small splash droplets are generated which are carried into the furnace’s top space. A model proposed for the formation of the smaller splash droplets predicted that the splash collected decreases exponentially with increasing height above the slag free surface from the point of splashing, and this is in agreement with the experimental results obtained.     

The Compositing Buffer: A Flexible Method for Image Generation and Image Editing

In this paper, we describe a new buffer architecture called the Compositing Buffer. Although it is based on the A-buffer architecture described by Carpenter¹, the new architecture introduces two important ideas which make image generation more flexible. The first idea is the storing of bitmask index instead of the bitmask. This allows accurate images to be generated while at the same time, minimising memory usage. The second idea is the introduction of the concept of dynamic object. This allows images to be edited interactively. Applications of the two ideas will also be discussed in the paper.     

Deindustrialization and regionalization: Class alliance and class struggle

The process of deindustrialization is place-specific, and is partly responsible for the redefinition of the regional structure and the transformation of the basis, function and scale of regional differentiation. Defined as a secular, uncompensated devaluation of capital, it is part of a larger spatial restructuring, associated with economic crisis. Most participants in the debate over deindustrialization have assumed that some form of class alliance is the best strategy for workers to pursue in overcoming the regional unemployment problems caused by deindustrialization. This paper argues the opposite.     

Effects of an explicit group contract on self-disclosure and group cohesiveness.

Assigned 96 male undergraduates to small groups based on their scores on a 40-item self-report survey derived from the Self-Disclosure Questionnaire. Half the groups received an explicit self-disclosure contract while the other half received no contract. Findings show that (a) the contract served to increase significantly both the frequency and depth of self-disclosure but did not affect the level of intimacy of topics discussed; and (b) the contract significantly enhanced the cohesiveness of the groups (i.e., attraction to the group) but had the opposite effect on members' mutual liking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concentration of alcohols by adsorption on silicalite

Silicalite, a zeolite analogue, selectively adsorbs organic molecules from aqueous solution, the adsorption depending on the stereochemistry and organophilic nature. This provides a possible economic route for the separation of alcohols from dilute solutions. Ethanol has been concentrated from a 2% (w/v) solution to 35%, and butan-1-ol from 0.5 to 98% (w/v) by adsorption on silicalite and subsequent thermal desorption.     

Response productivity: A methodological problem in content analysis studies in psychotherapy.

Contends that most content analysts of psychotherapy materials have failed to consider the possibility that the frequency of units coded to the categories of the content analysis system might be correlated with the total number of units produced. The existence of such relationships may confound interpretation of the association between content analysis variables and other external variables. When investigators have attempted to control for response productivity, they have usually divided the frequency of units in each category by the total number of units. This procedure does not control for response productivity and is often uninterpretable. The issues involved are discussed and demonstrated, and appropriate techniques of controlling for productivity are described. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical Properties of 6H-BaTi0.95M0.05O3−δ Ceramics where M = Mn, Fe, Co and Ni

Hexagonal BaTiO₃ materials have been stabilised at room temperature according to the formula BaTi_0.95M_0.05 O_3– where M = Mn, Fe, Co and Ni. Dense ceramics (> 96% of the theoretical X-ray density) were sintered at 1450C in flowing O₂ gas from calcined powders prepared by the mixed oxide route at 1300C. All samples were single-phase and the bulk conductivity, _b, measured by Impedance Spectroscopy and Q.f measured by microwave dielectric resonance methods showed a strong dependence on the type of dopant. _b at 300C was 10^–7, 10^–5.5, 10^–5.5 and 10^–4 Scm^–1 for M = Mn, Fe, Ni and Co, respectively and Q.f at 5 GHz was 7790, 6670, 2442 and 1291 GHz, for M = Mn, Fe, Ni and Co, respectively. The correlation between _b and Q.f is attributed to the presence of oxygen vacancies and/or mixed valency of the dopant ions.     

Spatial analysis of annual air pollution exposure and mortality

The aim of this study was to relate ambient air pollution levels to mortality in Auckland, New Zealand. We used urban airshed modelling and GIS-based techniques to quantify long-term exposure to ambient air pollution levels and associated mortality. After adjusting for age, sex, ethnicity, socio-economic status, and urban/rural domicile there was a 1.3% (95%CI: 1-1.5%) increase in non-external cause mortality, and 1.8% (95%CI: 1.5-2.1%) increase in circulatory and respiratory causes per 1 microg/m(3) increase in annual average NO(2). Based on these exposure-response relationships and applying an annual average threshold of 13 microg/m(3), the average annual (for 1996-1999) number of people estimated to die from non-external causes and circulatory and respiratory causes attributable to air pollution in Auckland is 268 (95% range: 227-310) (3.9% of total all cause deaths) and 203 (95% range: 169-237) (5.9% of total circulatory and respiratory deaths) per year, respectively. The number of attributable deaths found in this study are consistent with a previous New Zealand risk assessment using a different methodology, and is approximately twice the number of people dying from motor vehicle accidents in the region, which is on average (1996-1999) 103 per year. The GIS-based exposure maps identify high exposure areas for policy developers and planners in a simple and realistic manner. Taken together with overseas studies the study provides additional evidence that long-term exposure to poor air quality, even at levels below current standards, is a hazard to the public health.     

Modelling the VO2 kinetic response to heavy intensity exercise in children

The purpose of this study was to apply a series of mathematical models in order to investigate the nature of the kinetic response to heavy intensity exercise with children and identify a suitable model with which to estimate parameters of the response. Sixty two children (35 male, 27 female aged 10-15 years) completed four transitions from baseline pedalling to 40% of the difference between their previously determined anaerobic threshold and peak VO2 on an electronically braked cycle ergometer. Initially three models were fitted to the averaged response profiles following the end of phase 1. and their residuals compared; 1, a single exponential with a delay term; 2, an exponential and linear term with independent delays; and 3, a double exponential with independent delays. Up to 95% of the response profiles were better fitted by either model 2 or 3 (p < 0.05), and model 3 was a statistically better fit (p < 0.05) than model 2 in 77% of cases. Residual inspection confirmed the superior fit by model 3. A fourth model which consisted of a single exponential with a delay term was fitted within the phase 2 fitting window. Estimated parameters (A1 and tau1), using model 4 were not significantly different from model 3, and model 4 was identified as the model of choice due to the wide confidence intervals in tau2 and A2 using model 3. It was concluded that the nature of the response to heavy intensity exercise in children is similar to that previously reported with adults and that the response should be modelled accordingly.