De invloed van ijzerverbindingen op de intreeweerstand van enkele drainbuisomhullingen

In een opstelling wordt door een aantal vooromwikkelde drainbuizen van ca, 0.80 m lengte ijzerhoudend ruw grondwater gevoerd en de mate van ijzerafzettingen vergeleken

Towards F1 Hybrid Seed Potato Breeding

Compared to other major food crops, progress in potato yield as the result of breeding efforts is very slow. Genetic gains cannot be fixed in potato due to obligatory out-breeding. Overcoming inbreeding depression using diploid self-compatible clones should enable to replace the current method of out-breeding and clonal propagation into an F1 hybrid system with true seeds. This idea is not new, but has long been considered unrealistic. Severe inbreeding depression and self-incompatibility in diploid germplasm have hitherto blocked the development of inbred lines. Back-crossing with a homozygous progenitor with the Sli gene which inhibits gametophytic self-incompatibility gave self-compatible offspring from elite material from our diploid breeding programme. We demonstrate that homozygous fixation of donor alleles is possible, with simultaneous improvement of tuber shape and tuber size grading of the recipient inbred line. These results provide proof of principle for F1 hybrid potato breeding. The technical and economic perspectives are unprecedented as these will enable the development of new products with combinations of useful traits for all stakeholders in the potato chain. In addition, the hybrid’s seeds are produced by crossings, rendering the production and voluminous transport of potato seed tubers redundant as it can be replaced by direct sowing or the use of healthy mini-tubers, raised in greenhouses

Elastohydrodynamic film thickness and temperature measurements in dynamically loaded concentrated contacts : eccentric cam-flat follower

This paper describes some results of local film thickness and temperature measurements in an eccentric cam-flat follower contact by means of miniature vapour deposited thin layer transducers. Complex transducer patterns can be realized by employing photolithography, allowing local measurements in axial direction. A full film will develop at relatively low speeds. At high speeds chemical reaction layer formation starts. Film thickness and temperature at both sides of the contact differed appreciably, thus invalidating the assumption of line contact. Under high loads and misalignment a constriction in the film thickness, typically for EHD contacts, appears at the heavy load side. Only after supporting the follower on a self-aligning elastic hinge, a line contact condition could be attained. Temperature variations of the follower surface were found to be moderate. The transducers worked well and have a satisfying life expectancy