Local Flow Behavior of Ceramic Slurries in Tape Casting, as Investigated by Laser–Doppler Velocimetry

The local flow behavior in a tape-casting unit for processing ceramic slurries was investigated by laser–Doppler velocimetry (LDV). The most remarkable feature of the LDV system used was its high spatial resolution (24 μm) and temporal resolution (5 μs). A translucent Newtonian model fluid which, in the relevant processing window, at higher shear rates, exhibits a rheological behavior similar to that of a typical ceramic slurry, was chosen to determine the velocity distribution in the flow channel (i.e., in the tape-casting unit). The flow behavior was measured directly in several particular regions of the flow channel, which substantially consisted of a double doctor-blade assembly. The velocity distribution obtained below the forming doctor blade showed the strong influence of the casting speed on the flow behavior of the model fluid. Furthermore, the measured flow behavior was analyzed, based on the assumptions of fluid dynamics. Below the doctor blade, the flow behavior was considered to be a combination of pressure flow and drag (Couette) flow. The flow rates from the applied hydrostatic pressure and external drag forces were shown to be additive. A comparison between the measured velocity profiles and the model calculations showed excellent agreement. A flow reversal (secondary flow), never before measured quantitatively, was detected between the two inserted rectangular blades. Apparently, secondary flows influenced the surface properties of the cast green tapes.     

Blood is thicker than water: Kinship orientation across adulthood.

The importance of kin relationships was investigated across adulthood with 5 samples (total N=1,365). Within the personal networks, the genetic relatedness with relationship partners predicted subjective closeness (mean r=.50) and social support (mean r=.13). Effects were robust in 2 samples when controlling for residential proximity and contact frequency. These intraindividual correlations showed considerable variability and were interpreted as individual expressions of nepotism. The heritability of individual nepotism was zero. Variability of nepotism was unrelated to personality traits, but substantially related to sex, and parental and partner status. The authors discuss subjective closeness as 1 proximate cue to kinship, and suggest nepotistic adaptations as powerful mechanisms in social relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probe retrieval in ptychographic coherent diffractive imaging

Ptychography is a coherent diffractive imaging method that uses multiple diffraction patterns obtained through the scan of a localized illumination on the specimen. Until recently, reconstruction algorithms for ptychographic datasets needed the a priori knowledge of the incident illumination. A new reconstruction procedure that retrieves both the specimen's image and the illumination profile was recently demonstrated with hard X-ray data. We present here the algorithm in greater details and illustrate its practical applicability with a visible light dataset. Improvements in the quality of the reconstruction are shown and compared to previous reconstruction techniques. Implications for future applications with other types of radiation are discussed.     

Nachweis niedriger Lipase-aktivit?ten in Lebensmitteln

Zusammenfassung Ein spektrofluorimetrisches Verfahren basierend auf 4-Methylumbelliferylestern als Substrate wurde für die Bestimmung von Lipase-Aktivitäten in Lebensmitteln entwickelt. Es wurde erprobt u. a. mit Molken- und Eipulvern, Mandeln, Pfeffer, Paprika und Zimt. Außerdem wurden einige Lipasepräparate mikrobieller Herkunft analysiert. Die Nachweisgrenze der Methode liegt um eine bis zwei Zehnerpotenzen niedriger als die eines Test-Papiers, das Indoxylacetat als Substrat enthält.

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Detection of low lipase activities in foods

Summary A spectrofluorimetric procedure using 4-methylumbelliferyl esters as substrates was developed for the determination of lipase activity in foods. It was tested with among others whey and egg powders, almonds, pepper, paprika and cinnamon. In additon, some lipase preparations of microbial origin were analyzed. The detection limit of the method is one to two orders of magnitude lower than that of a test paper which contains indoxyl acetate as the substrate.

     

Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca sativa cv. Tamburo) grown in an inoculated hydroponic and soil system. The second aim was to quantify the level of contamination with the use of a proper surface sterilization method. Silver nitrate was superior in reducing the number of viable bacteria on leave surfaces compared to sodium hypochlorite and ethanol. With the hydroponic system internal colonization of lettuce only occurred at high densities with S. Typhimurium MAE 119. With the soil system E. coli O157:H7, S. Typhimurium 110 and S. Typhimurium 119 were found at considerable densities in sterilized leaf samples (respectively, 3.95, 2.57 and 2.37 log cfu/g on average) with prevalences of 0.29, 0.23 and 0.15, respectively. No statistical differences were observed between the Salmonella strains. A negative correlation was observed between shoot weight and leaf contamination. The observed presence of the pathogens in lettuce, after thorough surface sterilization, demonstrates the possible presence of human pathogens in locations were they are unlikely to be removed by the actions of consumer washing and therefore pose a serious threat when occurring in field situations.     

Microaerobic glycerol formation in Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae produces large amounts of glycerol as an osmoregulator during hyperosmotic stress and as a redox sink at low oxygen availability. NAD(+)-dependent glycerol-3-phosphate dehydrogenase in S. cerevisiae is present in two isoforms, coded for by two different genes, GPD1 and GPD2. Mutants for either one or both of these genes were investigated under carefully controlled static and dynamic conditions in continuous cultures at low oxygen transfer rates. Our results show that S. cerevisiae controls the production of glycerol in response to hypoxic conditions by regulating the expression of several genes. At high demand for NADH reoxidation, a strong induction was seen not only of the GPD2 gene, but also of GPP1, encoding one of the molecular forms of glycerol-3-phosphatase. Induction of the GPP1 gene appears to play a decisive role at elevated growth rates. At low demand for NADH reoxidation via glycerol formation, the GPD1, GPD2, GPP1, and GPP2 genes were all expressed at basal levels. The dynamics of the gene induction and the glycerol formation at low demand for NADH reoxidation point to an important role of the Gpd1p; deletion of the GPD1 gene strongly altered the expression patterns of the GPD2 and GPP1 genes under such conditions. Furthermore, our results indicate that GCY1 and DAK1, tentatively encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, may be involved in the redox regulation of S. cerevisiae.     

Reducing CO<Subscript>2</Subscript> emissions of cars in the EU: analyzing the underlying mechanisms of standards,registration taxes and fuel taxes

Road transport, especially passenger car transport, is one of the largest contributors to greenhouse gas emissions. The major elements of the strategy of the European Union (EU) in order to reduce car emissions—such as CO₂ emission regulations from new passenger cars, vehicle-related fiscal measures and fuel economy labelling—have not resulted in significant reductions of greenhouse gas emissions over the last two decades. We focus in this paper on the theoretical understanding of how different policy instruments affect the decisions of (rational) consumers with an emphasis on registration taxes. Our major conclusions are as follows: (i) Theoretical analyses of the effects of taxes and standards in car transport are already very informative for policy design, even before quantitative assessments with observed data are available; (ii) CO₂ emission standards will not deliver the theoretically possible CO₂ reduction due to the rebound effect, and they are questionable for regulating the average car as applied in the context of EU to car manufacturers; (iii) the rebound effect of standards depends on the service price elasticity, which plays also a crucial role how fuel taxes affect demand; the magnitude of the service price elasticity determines which of these instruments is more effective with respect to energy conservation; (iv) combining fuel taxes and standards may allow for a win-win situation for the environment and car drivers but not for the current kind of EU regulation; and (v) a registration tax is equivalent to a standard binding consumers’ decisions (this does not apply to the current EU regulation), in particular, both lead to demand rebounds.     

Variable speed wind turbine with radially oriented gear drive

A wind turbine assembly includes a gear drive assembly having an outer tubular member and an inner tubular member, the inner member being positioned coaxially within the outer member. A pair of spaced bearings circumscribe the inner tubular member and support the outer member for rotation about the inner member. Propeller blades are coupled to the outer member for effecting rotation in response to wind. An electric power generator mounted to the inner member has a rotor shaft extending from one end. A gear unit is drivingly coupled between the rotor shaft and the outer member whereby rotation of the outer member is effective to cause rotation of the rotor shaft at a velocity substantially greater than a rotational velocity of the outer member for generating electric power from the generator.     

Studies of the Anaerobic Leaching of Iron and Copper Containing Dump Material and Comparison to Chemical Leaching

The objective of this study was to investigate the leaching of a non-sulfide copper ore by a new bioleaching process, the Ferredox process. In the Ferredox process, Acidithiobacillus ferrooxidans reduces ferric ions and oxidizes sulfur at low pH under anaerobic conditions. In this study, a bacterial culture (mainly A. ferrooxidans) was initially grown aerobically. Bacterial dissolution of iron sludge under anaerobic conditions versus sulfuric acid was compared. An iron slurry sample from the West Rand Ditch near Hoyerswerda, Germany and from the Golestan Mine in Iran was investigated. Two shake flasks each containing an iron slurry and non-sulfidic Fe/Cu ore were used. One shake flask each was subjected to an anaerobic process by A. ferrooxidans, while the other sample was leached with dilute sulfuric acid. In the chemical leaching, the amount of dissolved copper was 2.5 %, only slightly higher than in the bioleaching. In a subsequent anaerobic column leaching with A. ferrooxidans, 35 % of the contained copper was mobilized from 1366 g ore.