Partial oxidation of methane over Rh/supported-ceria catalysts: Effect of catalyst reducibility and redox cycles

Partial oxidation of methane (POM) was studied over Rh/(Ce_0.56Zr_0.44)O_2−x, Rh/(Ce_0.91Gd_0.09)O_2−x, Rh/(Ce_0.71Gd_0.29)O_2−x and Rh/(Ce_0.88La_0.12)O_2−x. The effect of catalyst reducibility and redox cycles was investigated. It was found that the type of doped-ceria support and its reducibility played an important role in catalyst activity. It was also observed that redox cycles had a positive influence on H₂ production, which was enhanced as the number of redox cycle increased. Results of carbon formation are discussed as a function of ionic conductivity. Temperature programmed reduction (TPR) profiles, BET surface area, ionic conductivity and XRD patterns were determined to characterize catalysts. Catalytic tests revealed that of the materials tested, Rh/(Ce_0.56Zr_0.44)O_2−x was the most active material for the production of syngas, which correlates with its TPR profile. It was observed that doping CeO₂ with Zr, rather than with La or Gd caused an enhanced reducibility of Rh/supported-ceria catalysts.     

A calorimetric examination of coal surfaces

This communication reports the results of some exploratory experiments to examine the surface of coal by (i) flow microcalorimetry (FM) and (ii) vapour sorption calorimetry (VSC). Excepting differential scanning calorimetry, calorimetric methods have not been widely-exploited in coal structure research. The intent of this short communication is to demonstrate that hitherto neglected calorimetric methods are very rewarding when applied to the study of coal surfaces.     

Asphyxial death caused by a laryngeal schwannoma: a case report

Neurogenic tumours of the larynx are unusual, with approximately 115 cases reported in the literature to date. Most of these lesions are benign, solitary submucosal nodules which present with hoarseness and are amenable to surgical resection. We present a case of a large pedunculated schwannoma arising in the aryepiglottic fold associated with sudden asphyxial death in an otherwise healthy young female.     

Children's deliberateness of planning according to task circumstances.

89 children ages 4 to 9 solved mazes varying in the presumed appropriateness of advance or improvisational planning. Using a between-Ss design, children's performance was compared in a standard condition that stressed accuracy in problem solving (designed to increase the importance of advance planning to avoid errors) and a variation stressing speed (designed to favor improvisational planning). Performance was compared by varying maze structure in terms of whether errors in route choices could be identified from a search of a small portion of the maze (favoring improvisation) or from a search through the entire maze (favoring advance planning). Children's planning strategies were stable over trials and had predictable effects on error rates. Children's usage of deliberate planning strategies was related to the circumstances of the problem, with more advanced planning when the structure of the mazes and instructions favored that strategy. Children used less advance planning when speed was a consideration and when the maze structure allowed avoidance of errors without extensive search. Results show that children's planning strategies are adapted to circumstances, and suggest that older children may be more proficient in this adaptation than are younger children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reasserting the authority of science.

Argues that G. B. Melton (see record 1991-07135-001) misunderstood several aspects of the article by W. Gardner et al (see record 1989-32704-001) concerning the American Psychological Association's amicus briefs on adolescent abortion. The scope of a position presented for legal advocacy should depend on the quality of the empirical support for that stance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Novel Low-Temperature Synthesis of Nanosized NiZn Ferrite

Nanosized NiZn ferrite powder is synthesized by a low-temperature method, using a unique combination of citric acid and glycine. An appropriate molar ratio of both citric acid and glycine offers a low-temperature synthetic route by incorporating the complexation behavior of citric acid and the combustion nature of glycine. Thermal decomposition/controlled autocatalytic combustion of the composite gel occurs at a low temperature of around 175°C, with the evolution of a large amount of gases. Transmission electron microscopic studies showed that the average particle size of the ferrite obtained is ∼2.5 nm, with a narrow size distribution. Uniformly distributed fine-grained microstructure with low porosity is obtained for a sample sintered at 1000°C.     

Experimental investigation of the stiffness of critical components in a moment-resisting composite connection

This paper discusses results of experiments on an element of a proposed moment-resisting composite connection. The element is subjected to cyclic tension. A feature of this element is the use of blind bolts and extensions to these bolts into the concrete-filled CHS column. The test specimens with extensions failed at a higher load and showed increased initial stiffness compared to the specimen without extensions. The experimentally derived values of initial stiffness are also compared to the initial stiffness values derived from a mechanical component model of the connection element.     

Factors associated with acute and chronic pain following traumatic spinal cord injuries

Previous studies have estimated that between 25% and 45% of people with spinal cord injury report severe levels of chronic pain. Few studies have examined this longitudinally. This study examines the primary pain sites, intensity and variability of perceived pain in 76 patients, 6 weeks post injury and 45 patients from the same cohort, 8 year post discharge. Demographic information reveals a close similarity with the database (40,000) from Stover and Fine's cohort (1986). Data was assessed using visual analogue scales, measures were also taken of functional independence (FIM), emotional status and coping. At 6 weeks post injury, most pain is sited in the thoracic spine area, and in the upper and lower limbs. At 1 year post discharge, most pain is reported to be in the thoracic spine area, the lumbar region and the chest. Twenty-three per cent of the 6 week group reported that the intensity of their pain was severe, whilst at 1 year, 41% of the sample complained of severe pain. Factors associated with the pain at both time points were explored using correlational analyses. The emotional, functional and psychological factors that predict pain severity were explored using multiple regression analysis. Twenty-four per cent of those reporting moderate to severe pain at 6 weeks post injury were still reporting pain at 1 year post discharge. This study examines the relative contribution of psychological factors in reported pain.     

Wide-band GaInAs MISFET amplifiers

The authors present the first reported results on wideband GaInAs MISFET amplifiers. Using 1-μm-gate-length, 0.56-mm-gate-width GaInAs MISFETs, they obtained: (a) a power output of 230±30 mW (0.41 W/mm) with 33±3% power-added efficiency; (b) a power output of 265±15 mW (0.47 W/mm) with 30±3% power-added efficiency (both over the 7-11-GHz band), and (c) a power output of 220±45 mW (0.39 W/mm) with 32±4% power-added efficiency over the 6-12-GHz band. With a 0.7-μm-gate-length GaInAs MISFET, a small-signal gain of 5±0.5 dB over the 11.4-22.6-GHz band was obtained. These data include all connector, bias network, and circuit losses. The authors present an equivalent circuit model of these MISFETs based on S-parameter measurements. The model is essentially that of a MISFET with capacitors representing gate-to-source and gate-to-drain overlap capacitances added at input and output