Oxidation of SiCf/SiC‐HfB2 Composites under Laser Heating

Ceramic matrix composites with Sylramic^TM and CG Nicalon^TM SiC fibers and SiC‐HfB₂ matrices derived from a combination of polymer‐derived SiC ceramic and HfB₂ particulate slurries were prepared. The composites were tested for oxidation resistance by laser heating at 2 MW/m² to achieve temperatures near 1600°C. The oxidation resistance was compared between uncoated CG Nicalon^TM and BN‐coated Sylramic^TM fiber‐based composites. Oxidation resulted in precipitated nano‐sized HfO₂ independent of the fibers and fiber coatings.     

Thermal calculations on the ignition of a cotton bale by accidental contact with a hot particle

Previously presented ignition data for raw cotton are used in order to make predictions of hazards from hot particle entry into a previously thermally quiescent cotton bale. The calculations make use of a numerical approach to ignition by a heat source.     

Folate in Beer

Folate levels in a range of beers and other beverages have been measured using high‐performance liquid chromatography with fluorescence detection (HPLC‐FLD) and by liquid chromatography tandem mass spectrometry (LC‐MS/MS). The data from the LC‐MS/MS study was revealed to be unreliable, through the masquerading of polyphenol degradation products as folates. Using the HPLC‐FLD procedure most beers ranged between 2.2 and 24.2 μg per bottle, or up to 6.1% of the recommended daily allowance. Some imported beers contained no detectable folate and we believe that this is due to the folate decreasing in level during storage and transportation. Wine, vodka and whiskey contained no detectable folate, while orange juice contained folate at a comparable level to that found in the beer with the highest folate.     

Comparative study of arsenic removal by iron using electrocoagulation and chemical coagulation

This research studied As(III) and As(V) removal during electrocoagulation (EC) in comparison with FeCl₃ chemical coagulation (CC). The study also attempted to verify chlorine production and the reported oxidation of As(III) during EC. Results showed that As(V) removal during batch EC was erratic at pH 6.5 and the removal was higher-than-expected based on the generation of ferrous iron (Fe²⁺) during EC. As(V) removal by batch EC was equal to or better than CC at pH 7.5 and 8.5, however soluble Fe²⁺ was observed in the 0.2-μm membrane filtrate at pH 7.5 (10-45%), and is a cause for concern. Continuous steady-state operation of the EC unit confirmed the deleterious presence of soluble Fe²⁺ in the treated water. The higher-than-expected As(V) removals during batch mode were presumed due to As(V) adsorption onto the iron rod oxyhydroxides surfaces prior to the attainment of steady-state operation. As(V) removal increased with decreasing pH during both CC and EC, however EC at pH 6.5 was anomalous because of erratic Fe²⁺ oxidation. The best adsorption capacity was observed with CC at pH 6.5, while lower but similar adsorption capacities were observed at pH 7.5 and 8.5 with CC and EC. A comparison of As(III) adsorption showed better removals during EC compared with CC possibly due to a temporary pH increase during EC. In contrast to literature reports, As(III) oxidation was not observed during EC, and As(III) adsorption onto iron hydroxides during EC was only 5-30% that of As(V) adsorption. Also in contrast to literature, significant Cl₂ was not generated during EC, in fact, the rods actually produced a significant chlorine demand due to reduced iron oxides on the rod. Although Cl₂ generation and As(III) oxidation are possible using a graphite anode, a combination of graphite and iron rods in the same EC unit did not produce As(III) oxidation. However, a two-stage process (graphite anode followed by iron anode in separate chambers) was effective in As(III) oxidation and removal. The competing ions, silica and phosphate interfered with As(V) adsorption during both CC and EC. However, the degree of interference depends on the concentration and presence of other competing ions. In particular, the presence of silica lowered the effect of phosphate with increasing pH due to silica’s own significant effect at high pHs.     

AUTOMATIC DELINEATION OF FUNCTIONAL RIVER REACH BOUNDARIES FOR RIVER RESEARCH AND APPLICATIONS

The river reach is a pervasive term within contemporary river research and applications. Yet, despite its prevalence, there is a notable lack of consistency in its definition. This paper identifies the presence of two broad types of reach definition within the academic literature, operational and functional, and argues that a functional definition is more suitable for applications within river research and management. A range of sequence zonation algorithms that were originally derived for geological well‐log analysis were compared for their ability to automatically identify functional reach boundaries. An analysis of variance‐based global boundary hunting algorithm was identified as the most suitable. To demonstrate the potential practical applications of automatic reach delineation methods, two case studies where functional reach boundaries have been identified were described: first, in a sequence of predicted sediment transport capacities for use in a reach‐based sediment transport model; and second, in a sequence of RHS Habitat Quality Assessment scores for identification of lengths of channel in need of habitat restoration efforts. Finally, the paper discusses how this type of functional reach identification procedure might be applied in other areas of river research and applications and how a multivariate version of a statistical zonation algorithm might prove useful in facilitating integrated catchment management by identifying reach boundaries common across all variables of interest in the system. Copyright © 2011 John Wiley & Sons, Ltd.     

Multi-Censored Sampling in the Three Parameter Weibull Distribution

In life and fatique testing, multi-censored samples arise when at various stages of a test, some of the survivors are withdrawn from further observation. Sample specimens which remain after each stage of censoring continue to be observed until failure or until a subsequent stage of censoring. In this paper, maximum likelihood estimators and estimators which utilize the first order statistic are derived for the three parameter Weibull distribution. Estimators are also derived for the special case in which the shape parameter is known, a special case which includes the two parameter exponential distribution. An illustrative example is included.     

Sandtray therapy with a 24-year-old woman in the residual phase of schizophrenia.

Sandtray therapy is a clinical tool for helping a client express and understand his or her unconscious dynamics. It utilizes a sandtray and anywhere from a few hundred to a few thousand figurines in the room for the client to select from. These figurines cover a wide range of people, situations, and objects, from the most ordinary to the mythical. The client makes a story in the sand, which the client and therapist then discuss. It is standard therapeutic wisdom that one should not use techniques involving fantasy with psychotic clients since it is typically too hard for both them and the clinician to contain those fantasies in a healthy manner. Although this is very often true, the authors offer an example of how they were able to use sandtray to great therapeutic advantage with a schizophrenic client in the residual phase of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Respirometric Assessment of Primary Sludge Fermentation Products

This study investigates the potential of primary sludge fermentation for the generation of readily biodegradable substrate. Experimental evaluation indicates that uncontrolled fermentation converted 22% of the initial volatile suspended solids in the sludge into soluble biodegradable chemical oxygen demand (COD). More than 85% of the soluble COD generated was associated with the formation of short chain volatile fatty acids (VFAs). The recoverable fraction of the fermented sludge supernatant may potentially increase the biodegradable COD content of the primary effluent by 5%. The VFA composition predominantly involved acetic and propionic acids as reported in the literature. Due to the high VFA content, activated sludge Model No. 1 could not predict the COD fractionation in the primary sludge; activated sludge Model No. 3 provided a better interpretation of the oxygen uptake profile through initial storage of the VFAs in the sludge.