Alternative electro-chemically based processing routes for joining of plasma facing components

Tungsten is considered in fusion technology as functional and structural material in the area of blanket and divertor for future application in DEMO. The KIT design of a He-cooled divertor includes joints between W and W-alloys as well as of W with Eurofer-steel. The main challenges range from expansion mismatch problem for tungsten/steel joints over metallurgical reactions with brittle phase formation to crack stopping ability and excellent surface wetting. These requirements were only met partly and insufficiently in the past e.g. by direct Cu-casting of tungsten onto steel.Both, the joining needs and the observed failure scenarios of conventionally joined components initiated the development of improved joining technologies based on electro-chemical processing routes. As electrolytes aqueous and aprotic, water free, system are integrated into this development line. In the first step principle requirements are presented to guarantee a reproducible and adherent deposition of scales based on Ni and Cu acting as inter layers and filler, respectively, to generate a real metallurgical bonding as demonstrate by 1100 °C joining tests. The development field aprotic systems based on ionic liquids is discussed with respect to enable development of refractory metal based fillers with focus high temperature W–W brazing.     

Cd-free buffer layers for CIGS solar cells prepared by a dry process

ZnSe buffer layers for Cu(ln,Ga)Se₂/buffer/ZnO solar cells have been prepared by metal organic chemical vapor deposition (MOCVD). Using photoassisted MOCVD, deposition temperatures down to 265°C are possible. It is shown that deposition temperatures well below 300°C are essential as well as deposition times not much longer than 3 min. Higher temperatures and longer deposition times lead to absorber degradation. With optimized buffer deposition efficiencies of 11% have been obtained on CIGS absorbers from the Siemens pilot production line.     

Modern treatment options for the therapy of keratoconus.

The following case report describes the implantation of intrastromal corneal ring segments (ICRS) and the postoperative contact lens treatment in a 42-year-old patient with bilateral advanced keratoconus. The patient had a preoperative contact lens intolerance. After femtosecond laser assisted surgery and the implantation of ICRS new custom mini-scleral contact lenses were fitted. The postoperative subjective and objective contact lens tolerance was excellent.     

Phenolic resins for can coatings: II. Resoles based on cresol/phenol mixtures or tert. butyl phenol

The composition of two resoles based on cresol/phenol mixtures and of a resole manufactured from tert. butyl phenol were analysed by gas chromatography-mass spectrometry (GC-MS), comprehensive GC×GC, normal phase HPLC (NPLC) in combination with GC-MS and size exclusion chromatography (SEC). The cresol/phenol resin 2 contained perhaps 5000 components almost exclusively with methylene linkages between the rings. The resole from tert. butyl phenol largely consisted of components with 1-3 rings, about half of the linkages consisting of mono-methylene ether bridges. Comprehensive GC×GC provided the best picture of the sample composition, but the combination of NPLC with GC enables the most complete analysis.     

Epoxidized soy bean oil (ESBO) migrating from the gaskets of lids into food packed in glass jars

Epoxidized soy bean oil (ESBO) was determined in foods packed in glass jars closed by lids with a poly(vinyl chloride) (PVC) gasket. The methyl ester of a diepoxy linoleic acid isomer was measured, using transesterification directly in the homogenized food and on-line HPLC-GC-FID analysis. Infant foods from the Swiss market consisting of vegetables, potato and rice or muesli with fruits and berries contained less than 7 mg/kg ESBO, but meat (its fat?) strongly increased ESBO migration up to 86 mg/kg. Some 12% of the products exceeded 15 mg/kg. Austrian and Norwegian samples gave similar results. Edible oil strongly extracts the ESBO from the gasket in food contact within a few weeks. Since this part of the gasket on average contained 91 mg ESBO, the legal limit is likely to be far exceeded whenever the food contains free oil contacting the gasket, such as oily sauces or vegetables and fish in oil. In fact, the mean ESBO concentration in 86 samples was 166 mg/kg, with a maximum of 580 mg/kg.     

Photo-fenton degradation of diclofenac: identification of main intermediates and degradation pathway

In recent years, the presence of pharmaceuticals in the aquatic environment has been of growing interest. These new contaminants are important because many of them are not degraded under the typical biological treatments applied in the wastewater treatment plants and represent a continuous input into the environment. Thus, compounds such as diclofenac are present in surface waters in all Europe and a crucial need for more enhanced technologies that can reduce its presence in the environment has become evident. In this sense, advanced oxidation processes (AOPs) represent a good choice for the treatment of hazardous nonbiodegradable pollutants. This work deals with the solar photodegradation of diclofenac, an antiinflammatory drug, in aqueous solutions by photo-Fenton reaction. A pilot-scale facility using a compound parabolic collector (CPC) reactor was used for this study. Results obtained show rapid and complete oxidation of diclofenac after 60 min, and total mineralization (disappearance of dissolved organic carbon, DOC) after 100 min of exposure to sunlight. Although diclofenac precipitates during the process at low pH, its degradation takes place in the homogeneous phase governed by a precipitation-redissolution-degradation process. Establishment of the reaction pathway was made possible by a thorough analysis of the reaction mixture identifying the main intermediate products generated. Gas chromatography-mass spectrometry (GC/ MS) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) were used to identify 18 intermediates, in two tentative degradation routes. The main one was based on the initial hydroxylation of the phenylacetic acid moiety in the C-4 position and subsequent formation of a quinone imine derivative that was the starting point for further multistep degradation involving hydroxylation, decarboxylation, and oxidation reactions. An alternative route was based on the transient preservation of the biphenyl amino moiety that underwent a similar oxidative process of C-N bond cleavage. The proposed degradation route differs from those previously reported involving alternative degradation processes (ozonization, UV/H2O2, or photolysis), indicating that diclofenac degradation follows different pathways, depending on the treatment applied.     

Potential DNA–protein cross-link products formed by sugar degradation products: identification of N 6-[2-(N 2-2′-deoxyguanosyl)propionyl]lysine

Sugar degradation products are formed during heat treatment of food as well as endogenously in vivo. As reactive carbonyl compounds, they react readily with proteins or DNA to form protein- or DNA-bound advanced glycation end products (glycation reaction or Maillard reaction). In this study, we investigated the formation of potential DNA–protein cross-link products from sugar degradation products. 2-Deoxyguanosine, l-lysine and different carbohydrates were incubated at 37 °C. The sugar degradation products dihydroxyacetone and d,l-glyceraldehyde lead to the formation of two new cross-link products. The new compounds were isolated by preparative high-performance liquid chromatography and identified by spectral data as the two diastereomers of N⁶-[2-(N²-2-deoxyguanosyl)propionyl]lysine. In this structure, the -amino group of lysine and the exocyclic amine group of 2-deoxyguanosine are linked via a carboxyethyl group, derived from the carbohydrate component. The binding sites and the binding types were confirmed by synthesis of the analogous products from N²-(1-carboxyethyl)guanosine and N-acetyllysine methyl ester.Dedicated to Professor Th. Severin on the occasion of his 75^th birthday     

An enzymic method for differentiating thawed and fresh fish fillets

The specific activities of the lysosomal enzymes α-glucosidase and β-N-acetylglucosaminidase were determined in press juices and extracts from fresh and frozen/thawed fillets of cod, saithe, red fish and haddock. For each of the two enzymes it was found that the press juice/extract activity ratio increased following the freezing/thawing process (six to nine times for αglucosidase and three to five times for β-N-acetylglucosaminidase).