Laser-Doppler-Untersuchungen und einige theoretische Überlegungen zur Struktur von Totwasserströmungen

Ohne Zusammenfassung     

Model Estimates of the Contributions of Environmental Tobacco Smoke to Volatile Organic Compound Exposures in Office Buildings

Volatile organic compounds (VOC) in office buildings originate from multiple sources, such as outdoor air, building materials., occupants, office supplies, and office equipment. Many of the VOC found in office buildings are also present in environmental tobacco smoke (ETS), e.g., benzene, toluene, formaldehyde. Measurements made to date in office buildings have been interpreted by some to imply that the contributions of ETS to VOC exposures in office buildings are small. We have made a first order estimate of the contributions of ETS to VOC concentrations based on the VOC content of ETS and a time-dependent mass-balance model. Four different ventilation-infiltration scenarios were modelled for a typical office building. The results indicate that ETS can contribute significantly to total indoor levels of VOC in office buildings, even under moderate ventilation conditions. Ranges of concentrations for three of the four modelled scenarios substantially overlapped measured ranges of the compounds in office buildings. Average daytime concentrations of benzene from ETS, for example, for three of the four modelled scenarios, ranged from 2.7 to 6.2 μg m^?3, compared to reported measurements of 1.4 to 8.1 μg m^?3 for four office buildings. Under a “worst reasonable” case scenario, the average modelled ETS-contributed concentration of benzene was 33.9 μg m^?3 for a 40-hour work week.     

A comprehensive classification system for lipids

Lipids are produced, transported, and recognized by the concerted actions of numerous enzymes, binding proteins, and receptors. A comprehensive analysis of lipid molecules, “lipidomics,” in the context of genomics and proteomics is crucial to understanding cellular physiology and pathology; consequently, lipid biology has become a major research target of the postgenomic revolution and systems biology. To facilitate international communication about lipids, a comprehensive classification of lipids with a common platform that is compatible with informatics requirements has been developed to deal with the massive amounts of data that will be generated by our lipid community. As an initial step in this development, we divide lipids into eight categories (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids, prenol lipids, saccharolipids, and polyketides) containing distinct classes and subclasses of molecules, devise a common manner of representing the chemical structures of individual lipids and their derivatives, and provide a 12 digit identifier for each unique lipid molecule. The lipid classification scheme is chemically based and driven by the distinct hydrophobic and hydrophilic elements that compose the lipid. This structured vocabulary will facilitate the systematization of lipid biology and enable the cataloging of lipids and their properties in a way that is compatible with other macromolecular databases.[Reprinted with copyright permission from the Journal of Lipid Research. 2005. 46: 839–861.]     

Test and simulation of a solar-powered absorption cooling machine

At the Institut fuer Thermodynamik und Waermetechnik (ITW) a solar cooling machine has been built for demonstration purposes. The main part of the device is an absorber/desorber unit which is mounted inside a concentrating solar collector. The working pair consists of NH₃ used as the refrigerant and SrCl₂ used as the absorbing medium. Performance of the solar refrigeration unit was measured in a field test. The working principle of a periodically working, dry absorption cooling machine will be explained using the demonstration machine as an example. Results obtained from a field test performed in 1995 are presented and discussed. Further, a simulation program for the numerical simulation of a solar-powered dry absorption cooling machine has been developed and tested.     

The effect of free fatty acid on the reactivity of copper-based catalysts for the hydrogenolysis of fatty acid methyl esters

In the synthesis of fatty alcohols by hydrogenolysis of fatty acid methyl esters, small amounts of free fatty acids in the feed negatively affect the reactivity of copper-silica based catalysts. The effect of the acid was investigated in relation to the production of water, the nature of the inhibiting species, and the degree of reduction of the catalyst. Inhibition is reversible and not due to catalyst deactivation. Water is not the inhibiting species. Furthermore, formation of copper and zinc soaps was excluded. Lauric acid in the methyl ester feed reacts preferentially, but at a lower rate than the ester. Inhibition most likely stems from a preferential adsorption of the acid at the active sites of the catalyst. The consequences for practical applications are discussed.     

Amnesia as a consequence of male rape: A case report.

A male patient suffering from a generalized functional retrograde amnesia, for all autobiographical information, was admitted to a psychiatric inpatient facility. Psychological testing indicated possible sexual assault. Following five hypnotic sessions, the patient regained his memory, and a violent sexual attack by two males was validated. The amnesia is discussed in terms of the constructs of implicit versus explicit memory, and reasons why a male rape victim might suffer such an extreme reaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reactive processing of LLDPES in corotating intermeshing twin-screw extruder. II. Effect of peroxide treatment on processability

Commercial ethylene–octene linear low-density polyethylenes (LLDPEs) were reactively extruded with low levels of a peroxide [2,5-dimethyl-2,5-di(t-butylperoxy)hexane] to modify polymer molecular structure and processing properties. Peroxide levels were kept low to avoid crosslinking. This article reports the effects of this reactive extrusion on viscoelastic properties. Rheological properties are more sensitive than are molecular structure characteristics to the changes produced by reactions of very low peroxide concentrations. Complex viscosity increases are seen, especially at low frequencies. Shear-thining behavior is also accentuated. The crossover between G′ and G″ moves to lower frequencies. A modified Cole–Cole presentation of these data shows that the elastic component is more predominant for extrusion-reacted materials. Peroxide-modified materials all have higher Bagley end correction values than those of barefoot resins. The former exhibit lower power indices (more shear thinning). All these properties indicate more long-chain branching and higher melt elasticity. However, die swell decreased as a function of peroxide concentration. Peroxide treatment results in an enhancement of elongational viscosity, both under isothermal and cooling conditions, along with a decrease in drawdown ability. The rheological changes parallel those reported earlier in molecular characteristics but are more sensitive and suitable to evaluate the effects of reactive processing. The effectiveness of the reactive extrusion process for improving processability of LLDPEs depends critically on the extrusion conditions. © 1995 John Wiley & Sons, Inc.