Multiple-grooved Magnetic Traction Sheaves

This paper discusses a new and innovative form of traction sheaves, which can be used in many hoisting applications that are driven with wire ropes in material handling systems. By use of high performance permanent magnets, integrated in the periphery of traction sheaves, a significant increase of driving capacity is achieved. In this special case it concerns high energy magnets consisting of rare earth materials known as NdFeB magnets. These magnets provide a 20 times higher force than conventional magnets. The results of the research show that the driving capacity of traction sheaves with a round groove design can be increased by around 25% through the use of NdFeB magnets. By this means it is possible to combine high driving capacity with low wearout for the wire rope. Conventional traction sheaves with high driving capacity, such as Vgroove sheaves go along with fast wire rope deterioration because of the high local pressure stress on the rope

The Preservation of Inuit Clothing Collected during the Fifth Thule Expedition (1921-24)

Preparation procedures as well as ordinary use apparently cause changes in the appearance of Inuit skin clothing. These changes may alter the inherent properties of skin, such as fatty acid composition and shrinkage temperature. The present paper describes studies of fatty acid distribution and shrinkage temperature in a series of items of Inuit origin collected during the Fifth Thule Expedition (1921-24). The skins used for the clothing originate from ringed seal (Phoca hispida) and caribou (Rangifer tarandus). For comparison, fresh prepared skins were studied, as were samples of sealskins found in the mummy burial ground in Qilakitsoq, Greenland. It appeared that ordinary use changed the fatty acid distribution to some extent, as well as the shrinkage temperature, indicating slow deterioration. However, more significant deterioration was observed for samples exposed for longer periods to daylight as, for example, when placed on exhibition. The effect of light was verified by studying samples deliberately exposed to full daylight for ca. 6 months. In contrast to these samples, the 500-year-old skins appeared, on the basis of fatty acid distribution and shrinkage temperature, to be in good condition, possibly because of the lack of ordinary use in combination with low storage temperatures.Key words: Inuit, clothing, skin preparation, tanning, seal, caribou, fatty acid, preservation, Fifth Thule ExpeditionLes méthodes de préparation ainsi que l'utilisation normale provoquent, semble-t-il, des changements dans l'aspect des vêtements de peau inuit. Ces changements peuvent modifier les propriétés inhérentes de la peau, telles que la répartition des acides gras et la contractilité thermique. Cet article décrit les études portant sur la répartition des acides gras et la contractilité thermique dans une série d'objets d'origine inuit recueillis au cours de la cinquième expédition de Thulé (1921-24). Les peaux servant à l'habillement viennent du phoque annelé (Phoca hispida) et du caribou (Rangifer tarandus). À des fins de comparaison, on a étudié des peaux récemment préparées, ainsi que des échantillons de peaux de phoque trouvées dans le cimetière de momies de Qilakitsoq, au Groenland. Il semble que l'utilisation normale ait changé, dans une certaine mesure, la répartition des acides gras ainsi que la contractilité thermique, indiquant une détérioration lente. On a toutefois observé une détérioration plus importante pour des échantillons exposés durant de plus longues périodes à la lumière naturelle comme, par exemple, lorsqu'ils sont mis en exposition. On a vérifié l'effet de la lumière en étudiant des échantillons délibérément exposés au grand jour pendant environ six mois. Par contraste avec ces échantillons, les peaux de 500 ans semblaient, si l'on se fiait à la répartition des acides gras et à la contractilité thermique, en bon état, et ce, en raison peut-être du manque d'utilisation courante combiné à un entreposage à basse température.Mots clés: inuit, habillement, préparation de la peau, tannage, phoque, caribou, acide gras, conservation, cinquième expédition de Thul&eacute

Time-intensity transformation and internal stress in UV-curable hyperbranched acrylates

The photocuring of three different highly functional acrylates—Di-pentaerythritol penta/hexaacrylate (DPHA) and two hyperbranched molecules (HBP), one with a stiff polyester and one with a more flexible polyether structure—was investigated by means of photorheology, photo differential scanning calorimetry, and beam bending. Special attention was paid to the influence of the composition of DPHA/HBP reactive blends and UV intensity on gelation and vitrification and the resulting dynamics of the internal stress. It was found that adding HBPs to DPHA did not influence gelation significantly, but shifted the onset of vitrification to higher conversions and thus caused lower internal stresses in the material. Increasing UV intensity increased both the conversion at vitrification, thus retarding the build-up of internal stresses, and the ultimate conversion, thus increasing the final stress level. The obtained conversion, gelation, and vitrification data were assembled into time-intensity transformation diagrams, thus providing a useful tool for optimizing photocurin

Field emissions of N2O during biomass production may affect the sustainability of agro-biofuels

Field emissions of N2O during cultivation of bioenergy crops may counterbalance a considerable part of the avoided fossil CO2 emissions that are achieved by fossil fuel displacemen

The genes that carcinogens act upon

No abstract available