Design and analysis of the W7-X divertor scraper element

Thehigh heat-flux divertor of the Wendelstein 7-X large stellarator experiment consists of 10 divertor units which are designed to carry a steady-state heat flux of 10 MW/m². However, the edge elements of this divertor are limited to only 5 MW/m², and may be overloaded in certain plasma scenarios. It is proposed to reduce this heat by placing an additional “scraper element” in each of the ten divertor locations. It will be constructed using carbon fiber composite (CFC) monoblock technology. The design of the monoblocks and the path of the cooling tubes must be optimized in order to survive the significant steady-state heat loads, provide adequate coverage for the existing divertor, be located within sub-millimeter accuracy, and take into account the boundaries to other in vessel components, all at a minimum cost. Computational fluid dynamics modeling has been performed to examine the thermal transfer through the monoblock swirl tube channels for the design of the monoblock orientation. An iterative physics modeling and computer aided design process is being performed to optimize the placement of the scraper element within the severe spatial restrictions.     

Effect of the manufacturing conditions on the structure and performance of thin-film composite membranes

A systematic investigation of the influence of the manufacturing conditions on the structure and performance of thin-film composite (TFC) membranes is presented for polyamide (PA) supported by poly(ether sulfone) (PES). The TFC membranes were composed of an ultrathin PA layer synthesized by interfacial polymerization on top of a porous PES support layer formed by immersion precipitation. For the PES support layer, the role of the wetting pretreatment, initial casting film thickness, and relative air humidity were studied. Assuming a strong correlation between the thermodynamics and the hydrodynamics of the casting process, we derived new insights from scanning electron microscopy images and the experimental data. In view of optimization of the flux through the membranes, a wetting pretreatment should be avoided. Important polymer savings were obtained without a loss of performance through a decrease in the casting thickness in combination with the use of a very smooth support. Last but not least, a high air humidity during casting was found to inhibit the formation of a dense, defect-free skin layer. For the PA layer, the interfacial polymerization method, the drying method, and the curing time were studied. The clamping of the membrane in a frame with one side in contact with the piperazine (PIP) solution and the other side to the air yielded the highest membrane flux and rejection with the lowest use of PIP and trimesoylchloride solution. Because of the absence of a uniform PIP solution layer for some drying methods, nodular PA structures could be observed in the macrovoids of the underlying PES layer because of hexane intrusion; this resulted in a dramatic decrease in the flux. Moreover, the omission of the drying step did not result in a significant loss of performance and enhanced the ease of operation. Finally, a curing time of 8 min was found to be optimal. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Potential of yeast antagonists on invitro biodegradation of ochratoxin A

Six antagonistic yeast strains were screened initially for their ability to degrade Ochratoxin A (OTA) in liquid medium amended with OTA (7.5 μg ml^?1) and different concentrations of yeast cells at 30 °C. Highest OTA degradation was observed when the yeast cell concentration used at 1 × 10⁸ cells/ml ranging from 7.8 to 84%. Out of six yeast strains, three strains [Metschnikowia pulcherrima (MACH1), Pichia guilliemonodii (M8) and Rhodococcus erythropolis (AR14)] were selected for further studies. In preliminary studies yeast strains were evaluated for their ability to degrade OTA at different temperature regimes (10, 15, 20, 25, 30 and 35 °C) and found that 30 °C was the optimum temperature for yeast growth and highest OTA degradation ranging from 10.4 to 83.5%. These three strains were further evaluated to test their potential on OTA degradation using different concentrations of OTA (5 and 10 μg ml^?1) only at 30 °C. Three strains showed more or less same results with that of 7.5 μg ml^?1 concentration ranging from 7.5 to 81%. The three yeast antagonists were further tested to confirm either degradation or cell wall adsorption of OTA at different time intervals. Among the strains, MACH1 effectively degraded the OTA (>80%) at 30 °C after 15 days incubation compared to other strains tested and few amounts of OTA adsorption was observed in the yeast cell wall. LC–MS studies revealed that no by-product like α-OT or Phenylalanine was found during the degradation process. Therefore, further studies are needed to understand the mechanism of action of these yeast strains during OTA degradation.     

Die Rolle von Stärkeprodukten bei der Verleimung von Holzwerkstoffen mit Kunstharz-Leimen

The Role of Starch Products in Glueing of Wood Materials by Synthetic Resin Adhesives. In the wood processing industry considerable amounts of starch products are used as extender for the glueing with synthetic resin adhesives based on aminoplasts (urea and melamine resins). They are not only useful to reduce the costs for the adhesives but have to fulfil rheological, cross-linkage regulating and stress belancing actions. The amount of additives, of course, is limited by the quality standards for glueings. By investigation of mathematical-statistical evaluated plywood glueings the upper limit of the grade of extension has been determined. Furthermore, the possible reduction of prices by various extender/water additions has been calculated. The behaviour of extenders in the glueline can be examined by microscopic investigations of stained microtome sections from glued objects.     

Optimization of an Ex-Vivo Human Skin/Vein Model for Long-Term Wound Healing Studies: Ground Preparatory Activities for the ‘Suture in Space’ Experiment Onboard the International Space Station

This study is preliminary to an experiment to be performed onboard the International Space Station (ISS) and on Earth to investigate how low gravity influences the healing of sutured human skin and vein wounds. Its objective was to ascertain whether these tissue explants could be maintained to be viable ex vivo for long periods of time, mimicking the experimental conditions onboard the ISS. We developed an automated tissue culture chamber, reproducing and monitoring the physiological tensile forces over time, and a culture medium enriched with serelaxin (60 ng/mL) and (Zn(PipNONO)Cl) (28 ng/mL), known to extend viability of explanted organs for transplantation. The results show that the human skin and vein specimens remained viable for more than 4 weeks, with no substantial signs of damage in their tissues and cells. As a further clue about cell viability, some typical events associated with wound repair were observed in the tissue areas close to the wound, namely remodeling of collagen fibers in the papillary dermis and of elastic fibers in the vein wall, proliferation of keratinocyte stem cells, and expression of the endothelial functional markers eNOS and FGF-2. These findings validate the suitability of this new ex vivo organ culture system for wound healing studies, not only for the scheduled space experiment but also for applications on Earth, such as drug discovery purposes.     

Oxidative stability of vegetable purees enriched with n-3-LC-PUFA microalgal biomass: impact of type of vegetable

Vegetable purees can be interesting food products to enrich with omega-3 long-chain polyunsaturated fatty acids (n-3-LC-PUFA), since they are important carriers of nutrients and fibres and essential in a healthy diet. Due to their large number of double bounds, n-3-LC-PUFA are highly susceptible to lipid oxidation. Different vegetable purees, containing different types and amounts of endogenous antioxidants, may possibly show differences in oxidative stability. This study contributes to obtain more insight into the impact of the type of vegetable (broccoli, carrot or tomato) on the oxidative stability of purees enriched with heterotrophic (Schizochytrium) n-3-LC-PUFA-rich microalgal biomass. Therefore, different vegetable purees enriched with microalgae were compared with each other and analysed for their amount lipid oxidation products and antioxidants. Broccoli and tomato puree enriched with Schizochytrium showed a higher oxidative stability compared to enriched carrot puree. However, all of these Schizochytrium-enriched purees were prone to oxidation.     

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