Effects of manufacturing defects on the mechanical properties of carbon fibre reinforced polyethersulphone laminates

The effects of defects on the mechanical properties of carbon fibre reinforced polyethersulphone laminates have been measured. The defects studied were cut fibre plies, omission of polymer films and local delamination produced by the inclusion of foreign matter. Of these it was found that only cut plies had a significant detrimental effect on the strength of a laminate. For specimens with two cut plies, the failure stress, tensile, flexural and compressive in the remaining continuous plies was the same as in the defect-free material, provided that the cut plies were widely separated. However the failure stresses were 15–18% lower in the continuous plies in the specimens containing two cut plies which were more closely spaced and in specimens containing four cut plies.     

Elevated serum levels of soluble CD30 in patients with atopic dermatitis (AD)

The immunopathology of AD is still unclear, but evidence for an immune response polarized towards Th2 activity has been provided. The CD30 molecule belongs to the tumour necrosis factor (TNF) receptor family and is expressed on activated T cells with a sustained expression in Th2 cells. This molecule also exists in a soluble form (sCD30). Elevated serum levels of sCD30 have been found in patients with Hodgkin's disease, chronic hepatitis B infection and HIV infection. Studies were undertaken to compare the serum levels of sCD30 in patients with AD (n=49) and healthy non-atopic controls (n=94). The presence of sCD30 was analysed with ELISA. A significantly higher concentration of sCD30 was noted in AD patients, median sCD30 level 29 U/ml (range 1-708 U/ml), compared with healthy non-atopic controls (P<0.001), where the median level was 11 U/ml with a range of 1-1042 U/ml. No correlation was found between sCD30 levels and total serum IgE, or between the AD patients' SCORAD values and concentration of sCD30. sCD30 levels were also analysed in 20 AD patients, which during ketoconazole treatment had improved their clinical scores and reduced their serum IgE and eosinophil cationic protein levels. However, no significant decrease in sCD30 levels was noted after treatment. The results show that patients with AD have elevated levels of sCD30, but without correlation to total serum IgE or disease activity.     

A method for dynamic measurement of the resistance to dry heat exchange by footwear

Five different types of cold protective footwear have been tested with regard to their resistance to dry heat loss (i.e. the insulation) with a new electrically heated foot model. The model is able to simulate 'walking' movements in order to provide a more realistic simulation of wear conditions. Thermal insulation of shoes with and without a steel toe cap was the same. The insulating properties during simulated walking movements were 10-25% lower compared with static conditions. For two of the shoe models a significantly lower insulation value for the sole area was obtained when adding a weight of 30 kg. A significant difference could also be found between the insulation values of two different sizes of one of the models. Measurements with the standard method (EN 344) correlated well with the local insulation value of the sole part of the thermal foot. Correlation with the insulation value for the whole shoe was much less, variation was bigger and ranking in terms of cold protection differed between methods. The electrically heated foot model appears to provide a reproducible, accurate and more realistic method for measuring the insulation properties of shoes than EN 344.     

Leinöl in Farben und Lacken – Produkte mit hoher Human- und Umweltverträglichkeit

Linseed Oil – The Basis for Environmental Friendly Products Linseed oil has been used as binding material for manufacturing paints and varnishes since centuries. This old technique combined with modern know-how of industrial production will produce paints and varnishes for interior and exterior use corresponding the highest technical standards. Paints based on linseed oil are distinguished by a high compatibility for the human health and for the environment. Reducing indoor pollution linseed oil products will be of benefit for the human immune system and thus lessen the indoor stress known as “sick building syndrom”. An increased cultivation and use of linseed will give advantage for the consumer, the environment and the farming.     

On the kinetics of the autoxidation of fats: influence of pro‐oxidants,antioxidants and synergists

The influence of minor amounts of pro‐ and anti‐oxidants on the kinetics of the autoxidation of fat has been evaluated. The reaction rates of oxygen with the substrates were found to follow the same basic equation, hitherto established for pure substrates. There is evidence that the surface of the reaction vessel also acts as a reaction catalyst and its effect is proportional to the area of glass in contact with lipids. Oxidation is enhanced by trace metal ions as well as by surface‐active compounds (e.g. hydroperoxides and sterols). Antioxidants such as α‐tocopherol and butylated hydroxyanisole inhibit the oxidation by delaying the start of oxygen consumption (the induction period) while retarders like amino acids only decrease the rate of oxidation. Thus pro‐ and anti‐ oxidants affect either the start or the rate of oxygen consumption. The empirical formula dx/dt = k [O₂] (1‐x/n) f′(t) was found applicable to the different stages of oxidation.     

Influence of BaO on Pd/Al2O3-based catalysts in C2H4 and CO oxidation as well as in NO reduction

In this study, Pd/Al₂O₃ and Pd/BaO/Al₂O₃ metallic monoliths were used to investigate the effect of BaO in C₂H₄ and CO oxidation as well as in NO reduction. A FT-IR gas analyser was used to study the activity of the catalysts. Several activity experiments carried out with dissimilar feedstreams revealed that BaO enhances CO and C₂H₄ oxidation as well as NO reduction reactions in rich conditions. This effect is due to BaO, which causes a decrease in the ethene poisoning of palladium. In lean conditions BaO is present in the form of Ba(OH)₂ which reacts with oxidised NO releasing water. Therefore, NO was stored during the lean reaction.     

A planar integrated RCD snubber/voltage clamp

In order to reduce the cost, size, and weight of power electronic systems, it has become necessary to integrate electromagnetic structures, which until now have been constructed with discrete components. This approach not only reduces the component count, but also gives much greater control over parasitic elements. In this article, the authors describe an electromagnetically integrated resistor-capacitor-diode (RCD) snubber/voltage clamp that uses a planar construction technique. The design and construction are described and the performance is verified experimentally. Some advantages of the integrated component over its discrete counterpart are also given     

Bestimmung der Abtragungsraten von Zirconium,Tantal und der Legierung Tantal-40Niob in fluoridhaltiger azeotroper Salpetersäure mit Hilfe der Radiotracer-Methode

The radiotracer technique as a means to investigate the corrosion of zirconium, tantalum, and a Ta-40Nb alloy in fluoride containing azeotropic nitric acid Zirconium and tantalum as well as the tantalum 40% niobium alloy are of considerable technical importance due to their high corrosion resistance against numerous corrosive media. With respect to corrosion testing in analytically pure azeotropic nitric acid in the temperature range between 20 and 121°C, corrosion rates were determined for zirconium: 7 · 10^?6 to 5 · 10^?4 mm/y, for tantalum: 10^?8 to 4 · 10^?6 mm/y, and for the Ta-40Nb alloy: 2 · 10^?7 to 8 · 10^?6 mm/y [1]. These corrosion rates will be markedly increased by adding small amounts of fluorides or by fluoride impurities. The radiotracer method after neutron activation was applied to determine the corrosion rates in azeotropic fluoride containing nitric acid. Even minute additions of fluorides strongly affect the corrosion resistance of zirconium. In the range between 0.15 and 10 ppm F^? and at a temperature of 108°C, corrosion rates between 5.3 · 10^?3 and 3.1 mm/y were measured. It was impossible to establish a limit for the fluoride concentration, below which the corrosion rate of zirconium will not be adversely influenced. The corrosion rates of tantalum and the Ta-40Nb alloy are considerably increasing above a fluoride concentration of 10 ppm. The highest corrosion rates measured were between 8.4 · 10^?3 mm/y at 50°C/280 ppm F^? and 1.4 · 10^?2 mm/y at 110°C/320 ppm F^?. Within the range of this investigation, the corrosion resistance of tantalum was higher than that of the Ta-40Nb alloy by one order of magnitude. The corrosion resistance of zirconium and tantalum was not influenced by any treatment of the samples before testing.     

Primary prevention of malignant melanoma in the Stockholm Cancer Prevention Programme

The relation between intracoronary thrombus and endothelin-1 (ET-1) was studied. In a canine model, acute myocardial infarction (MI) was induced by coronary occlusive thrombus produced at a mock atheromatous plaque. Blood samples were collected from the aorta (A) and coronary vein (V). Twenty-eight open-chest dogs divided into three groups were studied. Group I (n = 15): acute MI was induced by coronary occlusive thrombus, and thrombolysis was obtained by urokinase two hours after MI. Group II (n = 8): nonocclusive thrombus was produced without inducing MI. Group III (n = 5): coronary artery was ligated for two hours and reperfused by release of ligation. In Group I, ET-1 was significantly increased after MI in A and V, and ET-1 in V was significantly more elevated than in A during thrombolysis, suggesting ET-1 production in the coronary vessels by thrombolysis. In Group II, ET-1 increased slightly during thrombus formation, but there was no difference in A and V. In Group III, ET-1 was elevated significantly after MI without A and V difference. These results indicate that there is no detectable ET-1 production with coronary thrombus formation, whereas coronary ET-1 production is detected during thrombolysis, most probably because resolved thrombus releases a more potent stimulus to ET-1 production.