Properties of high ash coal-char particles derived from inertinite-rich coal: II. Gasification kinetics with carbon dioxide

The reaction rate of carbon dioxide-nitrogen gas mixtures with a well-characterised high ash char derived from an inertinite-rich coal discard was investigated by experimentation and reaction rate modelling. Experimentation with a thermogravimetric analyzer at 87.5 kPa and 287.5 kPa between 850 °C and 900 °C and with 1mm diameter particles, similar to operating conditions used for bubbling fluidised bed gasification, was carried out. The char consisted of a large proportion of dense char formed from the inertinite in the parent coal, fine pores from the low concentration of reactive macerals and cracks formed as a result of thermal deflagration. The effects of carbon dioxide concentration, temperature and pressure on the carbon conversion with time were found to follow expected trends with long reaction times. The random pore model, which accounts for intraparticle structural changes, was examined to predict the overall reaction rate. For this evaluation, a new procedure was developed to determine the structural parameter which could not be calculated directly from initial characterisation results. This procedure consists of defining a reduced time parameter, which conveniently eliminates the effect of the intrinsic kinetics when conversion versus the reduced time results is used. Thus, the structural parameter, which characterises the pore growth and coalescence, can be evaluated by a regression procedure using experimental results obtained at all temperatures and pressures. Intrinsic reaction parameters based on the power rate law were also calculated from carbon conversion versus real time results using a stepwise regression procedure. It was found that the random pore model predictions for the carbon conversion with time using the determined parameters correlated very well with experimental results, thus confirming that the reaction rate is chemical-reaction controlled.     

Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: A 4-year follow-up study.

In a prior study of 54 relatives of patients with schizophrenia and 72 control participants, 3 neuropsychological functions met the criteria for risk indicators of the schizophrenia genotype: executive functioning, memory, and auditory attention. In an assessment of the stability of these findings, the sample was reexamined 4 years after the initial assessment. Three test scores were found to differ between groups (Immediate Verbal Memory, Delayed Verbal Memory, and Dichotic Listening Digits Detected) or to show a significant Group?×?Gender interaction (immediate and delayed verbal and visual memories). None of the test scores showed Group?×?Time interactions, suggesting that the discriminating power of the tests was stable over time. Evidence for deficits in working memory and rule learning on the object alternation test was also found. These results support the idea that neuropsychological dysfunction among relatives of patients with schizophrenia is a stable trait caused by the familial predisposition to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pre to post‐dialysis plasma sodium change better predicts clinical outcomes than dialysate to plasma sodium gradient in quotidian hemodialysis

Sodium balance across a hemodialysis treatment influences interdialytic weight gain (IDWG), pre‐dialysis blood pressure, and the occurrence of intradialytic hypotension, which associate with patient morbidity and mortality. In thrice weekly conventional hemodialysis patients, the dialysate sodium minus pre‐dialysis plasma sodium concentration (δDPNa+) and the post‐dialysis minus pre‐dialysis plasma sodium (δPNa+) are surrogates of sodium balance, and are associated with both cardiovascular and all‐cause mortality. However, whether δDPNa+ or δPNa+ better predicts clinical outcomes in quotidian dialysis is unknown. We performed a retrospective analysis of clinical and demographic data from the Southwestern Ontario Regional Home Hemodialysis program, of all patients since 1985. In frequent nocturnal hemodialysis, δPNa+ was superior to δDPNa+ in predicting IDWG (R² = 0.223 vs. 0.020, P = 0.002 vs. 0.76), intradialytic change in systolic (R² = 0.100 vs. 0.002, P = 0.02 vs. 0.16) and diastolic (R² = 0.066 vs. 0.019, P = 0.02 vs. 0.06) blood pressure, and ultrafiltration rate (R² = 0.296 vs. 0.036, P = 0.001 vs. 0.52). In short hours daily hemodialysis, δDPNa+ was better than δPNa+ in predicting intradialytic change in diastolic blood pressure (R² = 0.101 vs. 0.003, P = 0.02 vs. 0.13). However, δPNa+ was better than δDPNa+ in predicting IDWG (R² = 0.105 vs. 0.019, P = 0.04 vs. 0.68) and pre‐dialysis systolic blood pressure (R² = 0.103 vs. 0.007, P = 0.02 vs. 0.82). We also found that the intradialytic blood pressure fall was greater in frequent nocturnal hemodialysis patients than in short hours daily patients, when exposed to a dialysate to plasma sodium gradient. These results provide a basis for design of prospective trials in quotidian dialysis modalities, to determine the effect of sodium balance on cardiovascular outcome.     

Comparative in vitro evaluation of microspherical embolisation agents

This study describes the comparative performance of four commercially available microspherical embolisation products: Embosphere^TM, Embogold^TM, Contour SE^TM and Bead Block^TM. A series of in vitro evaluations were designed to assess the mechanical and biological characteristics of these biomaterials. Size distribution analysis revealed sieving techniques used to fractionate the embolics produced similar size distributions. The forces required to compress Embosphere, Embogold and Bead Block were in the range 21–27.5 kPa. Contour SE was significantly more compressible at ∼ 5 kPa. However, recoverability of Contour SE required several minutes in contrast to the other products, a phenomenon attributed to its macroporous structure. When time taken to reach and remain in suspension was studied, results showed that the products quickly reached equilibrium with contrast agent. Bead Block was maintained in suspension for twice as long as the other products. Catheter deliverability was assessed and found to be dependent upon both microsphere and catheter, the best combination being Bead Block delivered via the Progreat^TM catheter. Both the blood contacting SEM and plasma coagulation time showed none of the products were pro-thrombic or pro-coagulatory, each producing comparable results. Small differences in physical properties such as compressibility, could play an important role in delivery and effectiveness of vessel blockage. Currently all products are used routinely in clinical practice.     

Gelatin-based films containing hydrophobic plasticizers and saponin from Yucca schidigera as the surfactant

The aim of this study was to evaluate the incorporation of hydrophobic plasticizers (acetyltributyl citrate – ATB, tributyl citrate – TB and acetyltriethyl citrate – ATC) in a matrix of gelatin, using the saponin extracted from Yucca schidigera (yucca) as emulsifier, in the production of biodegradable emulsified films using the casting technique. High levels of hydrophobic plasticizers were incorporated, reaching up to 75% of plasticizer in relation to the protein (w/w) for ATB and TB, and up to 60% for ATC. The minimum values of water vapor permeability were 0.08, 0.07 and 0.06 g mm m^?2 h^?1 kPa^?1 for ATB, TB and ATC respectively, with no significant differences (p > 0.05). The water solubility of the films ranged from 21% to 59.5%. Although the WVP decreased, both scanning electron microscopy and laser scanning confocal microscopy indicated that the incorporation of the hydrophobic plasticizers did not occur homogeneously in the film matrix.     

Designing electronic use policies to enhance employee perceptions of fairness and to reduce cyberloafing: An empirical test of justice theory

Organizations are attempting to curtail cyberloafing or employee use of company Internet and email systems for non-work purposes by implementing electronic use policies, but their design is based on anecdotal support instead of theory or empirical research. Using procedural justice theory, we propose policies containing signed versus implied consent, for cause versus periodic monitoring, zero tolerance or progressive discipline versus managerial discretion in disciplinary procedures, and appeals to peers or management versus no appeals will improve employee perceptions of policy fairness and thus, decrease cyberloafing. Results from two experiments and a field study found that zero tolerance, progressive discipline, and appeal processes were related to higher perceptions of policy fairness while periodic monitoring was related to less cyberloafing.     

Workplace innovation: bridging knowledge and practice

The article draws on a decade of work in the UK by the UK Work Organisation Network (UKWON), and recommends a systematic approach. Taking cases in the National Health Service, the focus is on employee involvement, partnership and the development of social capital. High and low road approaches are compared, in an evaluation of the Improving Working Lives programme.

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FOOD SECURITY RISK LEVEL ASSESSMENT: A FUZZY LOGIC-BASED APPROACH

A fuzzy logic (FL)-based food security risk level assessment system is designed and is presented in this article. Three inputs—yield, production, and economic growth—are used to predict the level of risk associated with food supply. A number of previous studies have related food supply with risk assessment for particular types of food, but none of the work was specifically concerned with how the wider food chain might be affected. The system we describe here uses the Mamdani method. The resulting system can assess risk level against three grades: severe, acceptable, and good. The method is tested with UK (United Kingdom) cereal data for the period from 1988 to 2008. The approach is discussed on the basis that it could be used as a starting point in developing tools that may either assess current food security risk or predict periods or regions of impending pressure on food supply.     

FW2_5D: A MATLAB 2.5-D electrical resistivity modeling code

We present a 2.5-D forward modeling algorithm for electrical resistivity data. The algorithm incorporates a boundary condition and source singularity correction that greatly reduces the need to pad the model space. In addition, the algorithm includes an optimization method for estimating the appropriate Fourier coefficients to achieve an accurate 2.5-D approximation. The optimization scheme uses a gradient-based search to find the optimal coefficients. We compare results from our algorithm to two analytical solutions. We are able to achieve errors on the order 1% when compared to these models. We have implemented the algorithm as an open source MATLAB-based forward modeling package. The MATLAB code is useful for exploring subsurface current flow. It has been coded so that it can be easily ported to work with inversion routines. The code is computationally efficient and suitable for solving 2-D problems with a large number of model parameters.     

Individuality and Social Influence in Groups: Inductive and Deductive Routes to Group Identity.

A distinction between forms of social identity formation in small interactive groups is investigated. In groups in which a common identity is available or given, norms for individual behavior may be deduced from group properties (deductive identity). In groups in which interpersonal relations are central, a group identity may also be induced from individual group members' contributions, making individuality and individual distinctiveness a defining feature of the group (inductive identity). Two studies examined the prediction that depersonalization produced by anonymity has opposite effects for groups in which social identity has been induced or deduced. Results confirmed the prediction that depersonalization increases social influence in groups whose identity was more deductive. In contrast, depersonalization decreases social influence in inductive identity groups. Implications for the role of social identity in small groups are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)