Influence of montmorillonite layered silicate on plasticized poly(l-lactide) blown films

Plasticized poly(l-lactide) (PLA) montmorillonite layered silicate (MLS) nanocomposites were compounded and blown-film processed using a co-rotating twin screw extruder. PLA was mixed with 10 wt% acetyltriethyl citrate ester plasticizer and 5 wt% of an organically modified montmorillonite at various screw speeds. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) determined that the compounded pellets and the blown film PLA/MLS nanocomposites were intercalated. The effect of processing screw speeds on the barrier, thermal, mechanical, and biodegradation properties of the nanocomposites were analyzed and compared to the neat polymer. Nanocomposite films show a 48% improvement in oxygen barrier and a 50% improvement in water vapor barrier in comparison to the neat PLA. The thermogravimetric analysis (TGA) showed an overall 9 °C increase in the decomposition temperature for all of the nanocomposites. Differential scanning calorimetry (DSC) has determined that the glass transition, cold crystallization and melting point temperatures were not significantly influenced by the presence of MLS. Mechanical properties of the nanocomposites showed that the Young's modulus increased by 20% and the ultimate elongation of the nanocomposites were not sacrificed in comparison to the neat samples. Biodegradation rates in soil were slightly greater for the PLA/MLS nanocomposite than the pure PLA. However, none of the PLA pure and nanocomposites achieved significant biodegradation levels after 180 days.     

Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis

In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (D(f)). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.     

Scouring at Bed Sills as a Response to Flash Floods

The temporal development of clear-water local scour depth at bed sills in uniform gravel beds is considered. Experiments are presented on the development of scour holes under unsteady hydraulic conditions, with the triangular-shaped hydrographs tested being of different durations and different rates of flow variation. Based on the experimental results and a theoretical framework, a method is given for the definition and prediction of the scouring process under unsteady flows in terms of a dimensionless temporal parameter. A “flash flood” is here defined as an event for which the scour doesn’t attain its potential magnitude, i.e., the equilibrium value for the peak hydrograph flow rate. This flood nature is dependent on both the characteristics of the flood event itself and the characteristics of the stream. A quantitative measure of what constitutes a flash flood is given in terms of the identified temporal parameter. Results show that the ratio between the final scour depth and the potential scour depth at a bed sill for a given hydrograph can be estimated as a function of the identified temporal parameter.     

Recent Experiences with Listeria monocytogenes in New Zealand and development of a food control risk-based strategy

A risk-based strategy for Listeria monocytogenes has been developed by New Zealand Food Safety Authority. Incidents of L. monocytogenes in ready-to-eat foods reported to the regulatory authority were analysed to identify common factors that contributed to the contamination. In addition, the current regulatory framework and available food industry guidance were reviewed to prepare a strategy that will provide a consistent and informed approach to managing the risk of L. monocytogenes. Also recognised is the future impact of an aging population and an increase in the availability and range of chilled ready-to-eat foods that should be integrated into the strategy if an objective of ‘no increase in the reported incidence of foodborne listeriosis after five years’ is to be achieved.     

Similarities and differences in four views of David.

In this article, each author gives a brief comment on similarities he or she sees throughout the case formulations captured in the articles by Watson (2010a), Silberschatz (2010), Goldfried (2010), and Caspar (2010). A systematic comparison is added. Overall, the impression is confirmed and maintained that if authors are ready to renounce the use of the jargon of their specific approach, many similarities can be found. There are nevertheless differences that would lead us to expect a different course of therapy and different effects beyond the main effect of recovery in the case of David, pursuing the conceptualization and interventions proposed by Watson (2010b). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of genotype and sowing date on phytostanol–phytosterol content and agronomic traits in wheat under organic agriculture

Cereals are an important source of sterols and stanols in the human diet. The present study underlines the effect of genotype and weather conditions in bread wheat, on total sterol and stanol content (TSS), agronomic traits, proteins and ash content under organic conditions. Variations in TSS as well as other characters between two sowing dates were observed. A broad genotypic variability was also reported since extreme genotypes differed by more than 30 mg 100 g⁻¹ DW for TSS, with total stanol content varying twofold. Moreover, two groups of genotypes that differed in agronomic production, ash and protein content were depicted, based on their response to an increase in temperature. This result suggests that the genotypic factor prevails over the sowing date factor for determining sterol and stanol traits in wheat cultivated under organic conditions. Nevertheless, a strong interaction exists between the two factors, which can be used to drive bioaccumulation of these molecules.     

Induction time studies of calcium carbonate in ethylene glycol and water

Induction time for precipitation of calcium carbonate precipitated in mono ethylene glycol and water has been studied by conductivity measurements at ethylene glycol concentrations of 0–90 wt% and temperatures from 25 to 80 °C. The supersaturation ratios, S, were in the range of 3–10. The effect of the solvent was separated from the effect of the supersaturation and temperature. Increasing the concentration of ethylene glycol prolongs the induction times for precipitation of CaCO₃ considerably although the supersaturation actually increases, especially at lower temperatures. It was shown that this effect cannot be explained by the change in the interfacial tension. Induction time studies in seeded and unseeded experiments were performed in order to separate changes in the nucleation rate from the impact of the growth time in the varying solvent compositions. The results show that crystal growth is retarded, causing the increased induction time in ethylene glycol containing solutions, and hence that the nucleation rate is actually promoted by ethylene glycol. The nucleation rates determined by measured particle numbers and induction times from unseeded experiments were underestimated for the same reason, thereby illustrating the complexity of nucleation rate investigations in mixed solvents.     

Case formulation in EFT.

A case formulation, for a client with depression, based on emotion-focused therapy treatment principles will be presented. The client was seen for 16 sessions in emotion-focused therapy. Based on information provided in the first interview, the therapist discusses how the client’s issues can be formulated in an emotion-focused treatment by attending to different process markers, including markers of characteristic styles of being or ways of treating the self and emotional experience; modes of engagement or ways that emotional experience is processed in terms of whether it is overregulated or underregulated; specific in-session tasks like focusing, two-chair or empty chair work; and micromarkers of nonverbal behaviors including vocal quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal packing of material flow on conveyor belts

We are interested in an optimal packing density problem for material flows on conveyor belts in two spatial dimensions. The control problem is concerned with the initial configuration of parts on the belt to ensure a high overall flow rate and to further reduce congestion. An adjoint approach is used to compare the optimization results from the microscopic model based on a system of ordinary differential equations with the corresponding macroscopic model relying on a hyperbolic conservation law. Computational results highlight similarities and differences of both optimization models and emphasize the benefits of the macroscopic approach.