VOC sorption and diffusion behavior of building materials

In this study 25 different building materials often used in timber constructions (wood based panels, gypsum boards, vapor barriers, adhesive tapes, insulation materials and sealants) were investigated with regard to their adsorption, desorption and diffusion behaviour towards volatile organic compounds (VOC). The materials were exposed to four, respectively five selected VOCs typically found in indoor air: hexanal, butyl acetate, p-xylene, nonane and α-pinene. Adsorption and desorption properties were investigated under static conditions, whereas the diffusion behavior was examined in a 0.225 m³ emission chamber with an air exchange rate of 1 h^?1. The results of the experiments indicate that some building products have a high potential to reduce VOCs in indoor air. Apart from the vapor barriers, two insulating materials and one plasterboard, all tested materials represented an adsorption efficiency of about 50 % or higher related to the injected VOC standards. Materials with high adsorption capacity bound substances strongly and desorbed them less, whereas less adsorbing materials acted inversely. The obtained results indicate that material properties and processing play a considerable role in diffusion behavior of building materials.     

On dioxin formation in iron ore sintering

Iron ore sintering is an important source of "dioxins", polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This paper reports on attempts to identify materials, conditions, and mechanisms responsible for PCDD/F formation (i) by investigating salient properties of ores (viz., with respect to oxidation, condensation, and chlorination of model organics) and (ii) by mimicking the industrial process on a microscale with real-life materials. Principles of Design of Experiments (DOE) are employed. The reactivities of iron ores differ greatly. Limonite/goethite "soft" ore is a very active oxidation catalyst (e.g., for benzene and phenol), a property that may be useful in cleaning up crude sintering process offgases, whereas hematite/magnetite "hard" ore is not. The latter, however strongly promotes condensation of phenol to dibenzofuran. A newly built lab-microscale sintering facility could satisfactorily imitate the large-scale process, in part or as a whole. Results obtained with realistic feed mixtures point at dioxin formation in the sinter bed at levels significant enough to explain a major part of the outputs observed in the real-life process. With approximately 8 ppm (wt) of chloride added as NaCl, the PCDD/F output doubled, but with the same proportion of chlorine administered as C2Cl4, the dioxin output was over 2 orders of magnitude larger. The use of process reverts, etc. containing chlorinated organics should therefore be avoided. PCDD/F congener patterns are also reported and compared with those observed in practice.     

新工艺超越摩尔定律限制

美国莱斯大学(Rice University)和北卡罗莱纳州立大学的一个研究小组日前公布了一种新工艺:把分子贴到半导体硅表面.研究小组声称,这种方法有助于电子制造商超越当前摩尔定律的极限,从而可以制造出体积更小、性能更强的微处理器.     

我国研制成功10GHz8bit超高速DDS芯片

美国莱斯大学(Rice University)和北卡罗莱纳州立大学的一个研究小组日前公布了一种新工艺:把分子贴到半导体硅表面。研究小组声称,这种方法有助于电子制造商超越当前摩尔定律的极限,从而可以制造出体积更小、性能     

激光打印机对空气质量的影响研究新进展

德国布伦瑞克大学夫朗和费WKI研究所(Fraunhofer wilhelm Klauditz Institute)和澳大利亚布里斯班昆士兰大学的研究者经过合作研究,得出结论,他们认为激光打印机在工作时散发出来的超微细粒子并不是人们想象的炭粉颗粒,而是一些像石蜡、硅油这样的挥发性物质.这些超微细粒子的一个关键特点是挥发性,这就表明它显然不是炭粉,WKI材料分析与室内化学系的领导人Tunga Salthammer教授解释说.     

The expression of affect in African elephant (Loxodonta africana) rumble vocalizations.

Affective states are thought to be expressed in the mammalian voice, but such investigations are most common in primates. Source and filter features of rumbles were analyzed from 6 adult female African elephants (Loxodonta africana) at Disney’s Animal Kingdom. Rumbles produced during periods of minimal social interaction (“low affect”) were compared to those produced during dominance interactions (“high affect”). Low-ranking females produced rumbles with increased and more variable fundamental frequencies, and increased durations and amplitudes during dominance interactions with superiors, compared to the low affect context. This acoustic response is consistent with the expression of affect in mammals and may signal submission to superiors. The 2 highest ranking females were codominant and competed for alpha status. They produced rumbles with decreased and less variable fundamental frequencies, increased durations and amplitudes, and a decrease in formant dispersion during dominance interactions with each other, compared to the low affect context. This response is not generally consistent with the expression of affect, but may signal large body size to competitors. These results suggest that affect can be expressed in the voiced sounds of elephants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Youth sport participation—a view of the issues: Introduction to the special section.

Sport participation among children and youth is ubiquitous in U.S. society. As such, it is imperative to understand how and under what conditions youth engagement in organized sport promotes or interferes with development. Each article in this special section has a unique lens on sport programs and advances our understanding about the contributions of individual characteristics, features of the context, and the process between the two that leads to different developmental trajectories for youth. In combination, the perspectives and findings provided in these articles can help guide future research and the development of programs and interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel recovery in a bilingual aphasic: A neurolinguistic and fMRI study.

In bilingual aphasics, the neural correlates of rehabilitation benefits and their generalization across languages are still scarcely understood. The authors present the case of a highly proficient bilingual woman (Flemish, L1/Italian, L2) with chronic aphasia who, in the presence of the same pattern of impairment in both languages, showed parallel recovery in both languages after long-term rehabilitation therapy in L2. The authors postulated that this recovery was due to the engagement of the same neural substrates. To confirm this the authors used an event-related functional magnetic resonance imaging (fMRI) paradigm to explore cortical activation during an overt picture naming task, performed in both Flemish and Italian once before and once after 2 weeks of training in L2. Behaviorally, the patient showed complete recovery of both languages. The fMRI results indicated that the same cerebral regions were recruited for both languages before and after training. Increasing activations were observed perilesionally and in homologous contralesional areas. Our data, in agreement with previous results of fMRI studies in healthy bilinguals, indicate a promising direction for future research on the neural mechanisms associated with recovery in bilingual aphasics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuous monitoring of yoghurt fermentation using a noble metal electrode array

An electrochemical probe containing gold, platinum and rhodium working electrodes was used to monitor yoghurt production in a pilot facility. Three commercial starting cultures at 40, 42 and 44 °C transformed milk having 1.5% fat content to mild yoghurt products. The electrochemical changes in the broth during fermentation were recorded as current responses from pulse voltammetry over the electrodes. Principal component analysis of the responses generated two-dimensional score plots describing the qualitative fermentation progressions. Two distinct fermentation pathways were observed leading to similar final products. The pH was recorded during the fermentations and the data was used as reference values for creating a partial least squares model for prediction of pH as an example of a quantitative application for the sensor. The relative mean squared error for validation of the model using four probes interchangeably was about 2%. The probe was constructed of materials approved for use in the food industry and did not require a standard glass reference electrode.