Transport Properties of Bulk Thermoelectrics: An International Round-Robin Study, Part II: Thermal Diffusivity, Specific Heat, and Thermal Conductivity

For bulk thermoelectrics, improvement of the figure of merit ZT to above 2 from the current values of 1.0 to 1.5 would enhance their competitiveness with alternative technologies. In recent years, the most significant improvements in ZT have mainly been due to successful reduction of thermal conductivity. However, thermal conductivity is difficult to measure directly at high temperatures. Combined measurements of thermal diffusivity, specific heat, and mass density are a widely used alternative to direct measurement of thermal conductivity. In this work, thermal conductivity is shown to be the factor in the calculation of ZT with the greatest measurement uncertainty. The International Energy Agency (IEA) group, under the implementing agreement for Advanced Materials for Transportation (AMT), has conducted two international round-robins since 2009. This paper, part II of our report on the international round-robin testing of transport properties of bulk bismuth telluride, focuses on thermal diffusivity, specific heat, and thermal conductivity measurements.     

Salmonella Enteritidis in meat, poultry, and pasteurized egg products regulated by the U.S. Food Safety and Inspection Service, 1998 through 2003

The U.S. Food Safety and Inspection Service (FSIS) tests for Salmonella in meat, poultry, and egg products through three regulatory testing programs: the Pathogen Reduction-Hazard Analysis and Critical Control Point (PR-HACCP) program, the ready-to-eat program for meat and poultry products, and the pasteurized egg products program. From 1998 through 2003, 293,938 samples collected for these testing programs were analyzed for the presence of Salmonella enterica serotypes. Of these samples, 12,699 (4.3%) were positive for Salmonella, and 167 (1.3%) of the positive samples (0.06% of all samples) contained Salmonella Enteritidis. The highest incidence of Salmonella Enteritidis was observed in ground chicken PR-HACCP samples (8 of 1,722 samples, 0.46%), and the lowest was found in steer-heifer PR-HACCP samples (0 of 12,835 samples). Salmonella Enteritidis isolates were characterized by phage type, pulsed-field gel electrophoretic pattern, and antimicrobial susceptibility. Phage typing of 94 Salmonella Enteritidis isolates identified PT13 (39 isolates) and PT8 (36 isolates) as the most common types. One isolate from a ready-to-eat ham product was characterized as PT4. Electrophoretic analysis of 148 Salmonella Enteritidis isolates indicated genetic diversity among the isolates, with 28 unique XbaI electrophoretic patterns identified. Of these 148 isolates, 136 (92%) were susceptible to each of 16 antimicrobials tested. Two isolates were resistant to ampicillin alone, and 10 isolates were resistant to two or more antimicrobials. Isolation of Salmonella Enteritidis from FSIS-regulated products emphasizes the need for continued consumer education on proper food handling and cooking practices and continued work to decrease the prevalence of Salmonella in meat, poultry, and pasteurized egg products.     

Multiplex Real‐Time PCR Method for Detection and Quantification of Mycotoxigenic Fungi Belonging to Three Different Genera

Abstract: Cereal crop plants are colonized by many fungal species such as Aspergillus ochraceus and Penicillium verrucosum, which produce ochratoxins, and Fusarium graminearum, which produces trichothecene mycotoxins. A multiplex real‐time PCR method using TaqMan probes was developed to simultaneously detect and quantify these mycotoxigenic Fusarium, Penicillium and Aspergillus species in cereal grains. Primers and probes used in this method were designed targeting the trichothecene synthase (Tri5) gene in trichothecene‐producing Fusarium, rRNA gene in Penicillium verrucosum, and polyketide synthase gene (Pks) in Aspergillus ochraceus. The method was highly specific in detecting fungal species containing these genes and was sensitive, detecting up to 3 pg of genomic DNA. These PCR products were detectable over five orders of magnitude (3 pg to 30 ng of genomic DNA). The method was validated by evaluating sixteen barley culture samples for the presence of deoxynivalenol (DON) and ochratoxin A (OTA) producing fungi. Among the barley culture samples tested, 9 were positive for Fusarium spp, 5 tested positive for Penicillium spp, and 2 tested positive for Aspergillus spp. Results were confirmed by traditional microbiological methods. These results indicate that DON‐ and OTA‐producing fungi can be detected and quantified in a single reaction tube using this multiplex real‐time PCR method. Practical Application: This method would be helpful in detecting and quantifying the mycotoxin producing fungi such as Fusarium, Aspergillus, and Penicillium in cereal grains and cereal‐based foods.     

The role of problem definitions in understanding age and context effects on strategies for solving everyday problems.

The participants (107 preadolescents, 124 college students, 118 middle-aged adults, and 131 older adults) described 2 everyday problems (1 unconstrained, the other constrained to 1 of 6 domains) that they experienced and their goals and strategies. Problem definitions reflected interpersonal or competence components or both; strategies reflected altering cognitions, actions, or regulating and including others. Age differences in problem definitions were found. For unconstrained-domain problems, age and problem definition were related to strategies; for unconstrained-domain problems age differences in strategies were not found. For constrained-domain problems, strategies related to problem domain and problem definition, with problem definition the better predictor of strategies. The results illustrate the value of individuals' problem definitions for addressing age and context effects on strategies used. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prevalence of overweight and obesity in school-aged children.

PURPOSE: Childhood obesity is a public health concern in Canada. Few published anthropometric data are available to indicate obesity prevalence in Canadian children. Obesity prevalence is reported for school-aged children in 11 London, Ontario, schools. METHODS: Data on body weight and height were obtained using standardized procedures. United States Centers for Disease Control and Prevention (CDC) body mass index (BMI)-for-age references and Cole's international BMI reference were used to classify the children's weight categories. RESULTS: The study included 1,570 pupils aged six to 13. The CDC BMI references categorized 16.6% and 11.8% of children as overweight and obese, respectively. In comparison, when the Cole BMI reference and cut-off points were used, 17.5% and 7.6% of children were classified as overweight and obese, respectively. CONCLUSION: Overweight is prevalent in the study population. Public health interventions are warranted to curb the obesity epidemic in school-aged children.     

Studying the performance and agility of individuals using cooperative and competitive incentives

Cooperation and competition have frequently been compared to determine the impact on performance measures such as productivity and quality. A modern characteristic that is sought after is agility, which is defined as success in a turbulent environment. This research builds on past studies of cooperation and competition by including agility as a key performance measure. An experiment was conducted in which a group of individuals with cooperative incentives and another group with competitive incentives experienced alternating stable and turbulent environments. Statistically significant differences were found for completion times and overall scores for the stable versus turbulent trials, and for product quality and cleanliness for the cooperative versus competitive treatments. The cooperative individuals scored better in every category except agility. These results suggest that individuals working cooperatively can create higher quality products; however, competitive incentives may help achieve agility. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 105–115, 2007.     

Ten Years on: Review of Adjudication in the United Kingdom

The Housing Grants, Construction and Regeneration Act 1996 introduced statutory based adjudication into the United Kingdom. Since then there has been a volume of case law regarding enforcement of adjudication decisions and clarifications of procedural issues. This paper looks at the fundamentals of adjudication under the Housing Grants, Construction and Regeneration Act, trends in adjudication case law, and certain procedural clarifications from recent case law.     

The chemical modification of enzymes to enhance solubilization in organic solvents for interaction with coal

Some enzymes can effectively function as catalysts in contact with organic solvents in a variety of ways; however, it is desirable to utilize the enzyme in a soluble form for interactions with a solid substrate such as coal. Dinitrofluorobenzene (DNFB) has been used as the reagent to add dinitrophenyl groups to enzymes, thus increasing hydrophobicity and solubility (up to 20 mg ml⁻¹) in less-polar organic solvents ranging from dioxane to benzene. Mixed reducing enzymes modified by DNFB and used in pyridine or benzene under hydrogen have been shown to enhance significantly the solubility in organic solvents of coals ranging from lignite to bituminous, with up to 35.3 wt% coal conversion. A fluidized-bed bioreactor appears to be the most effective contactor.     

Impact of sulfate and nitrate incorporation on potassium- and sodium-based geopolymers: geopolymerization and materials properties

One of the most promising applications of geopolymers is their use as a waste encapsulating matrix. These binders are indeed compatible with aqueous waste streams and capable of activating several chemical and physical immobilization mechanisms for a wide range of inorganic waste species. Several works have investigated the immobilization of cations, mainly heavy metals or radioactive wastes, but very few studies have taken counterions, namely anions, into account. This work is an experimental investigation of the impact of anions with different valences on the material properties in regard to the requirements of an industrial process at ambient or slightly elevated temperature, including the setting time, maximum achievable compressive strength, or resistance to leaching. The modifications caused by the introduction of monovalent and divalent anions, such as sulfate and nitrate, are also evaluated in term of mineralogy, porosity, and microstructure. Their immobilization appears to be related to the progress of the geopolymerization reaction. Moreover, depending on the alkali ions used in the activation solution, the anionic species considered may also enhance the precipitation of some zeolites.