Modélisation et commande d’une hydrolienne équipée d’une génératrice asynchrone double alimentation

Cet article traite de la modélisation et de la commande d’un système de récupération de l’énergie des courants de marée ; à savoir une hydrolienne équipée d’une génératrice asynchrone double alimentation. Dans un premier temps et dans le but de pouvoir évaluer les performances et la dynamique de l’hydrolienne, dans différentes conditions de fonctionnement, un modèle multiphysique est implanté sous Matlab/Simulink®. Ensuite, une stratégie de commande MPPT sans capteur de vitesse de la génératrice asynchrone est proposée. Cette stratégie est éprouvée en regard de l’effet de la houle qui est considéré comme le plus à même de perturber le modèle de la ressource. La modélisation multi-physique et la commande à vitesse variable ont été testés sur une hydrolienne équipée d’une génératrice asynchrone double alimentation de 7,5 kW et en utilisant des données réelles du site du Raz-de-Sein (Bretagne) pour l’année 2007.Financement de thèse de Brest Métropole Océan

Quality Of Groundwaters In The Area Of The Łódź Basin

Published in: Origin of Relief of Central Poland and Its Anthropogenic Transformation in Łódź University Geographical Research, edited by. E.Kobojek, T.MarszałThe Łódź basin, and particularly its north-eastern fragment, has a very high economic importance in terms of abundance, still good quality of groundwaters, and their availability in the watershed zone. More than 150 years of anthropogenic pressure is currently only recorded in the qualitative aspect of groundwaters, affected by both the anthropopressure factors and geogenic conditions. The re sults of the regional monitoring, supplemented with own research of the Laboratory of Geology of the University of Łódź, show substan tial pollution of shallow aquifers. This is determined by a number of factors, not always related to urban landscape. Due to their nat ural conditions, deeper Cretaceous aquifers are much less polluted, although the pressure is higher within the small Łódź basin than outside of it. This relates to the forms and intensity of land manage ment, particularly in zones of alimentation of aquifers. The quality of groundwaters of the Łódź basin is also determined by geogenic factors, as exemplified by the Lower Cretaceous aquifer, locally of geothermal character. Contaminants penetrating groundwaters lead to the hydro chemical differentiation of waters in the same aquifer, particularly distinguishing its uppermost layer. Moreover, they cause the degra dation of other elements of the hydrosphere used by man, such as rivers right from their springs, and waters retained in usually small reservoirs. A change in the conditions of transport of pollutants re sults in the activation of some of their forms, e.g. biogenic substanc es, and leads to secondary changes in the quality of stagnant waters. From the perspective of time and area in which the Laboratory of Geology of the University of Łódź conducted research on ground waters in the years 1993–2013, a diminishment of old threats within cities, and activation of new ones outside of cities is observed, often in areas of alimentation of Cretaceous aquifers in the eastern part of the Łódź agglomeration. In the conditions of limited possibilities of registration of groundwater quality by the currently functioning regional monitoring system, and total withdrawal of elements of the national monitoring from the Łódź region, the functioning of our unit is supplemented by the system of identification and registra tion of groundwater quality in the region of the small Łódź basin. An example is the recording in summer of the current year of pollution with petroleum derivatives of a usable aquifer in the southern sub urbs of Łódź. Works on the determination of the scale of the threat for the surrounding intakes have been undertaken

Pancreatic islet transplantation after upper abdominal exeriteration and liver replacement

Nine patients who became diabetic after upper-abdominal exenteration and liver transplantation were given pancreatic islet-cell grafts obtained from the liver donor (eight cases), a third-party donor (one), or both (four). Two patients were diabetic when they died of infections after 48 and 109 days, as was a third patient who died of tumour recurrence after 178 days. The other 6 are alive 101-186 days postoperatively, and five are insulin-free or on insulin only during night-time parenteral alimentation. C-peptide increased 1·7 to 3·3 fold in response to intravenous glucose in these five patients who have had glycosylated haemoglobin in the high normal range. However, the kinetics of the C-peptide responses to intravenous glucose in all eight patients tested revealed an absent first-phase release and a delayed peak response consistent with transplantation and/or engraftment of a suboptimal islet cell mass. The longest survivor, who requires neither parenteral alimentation nor insulin, is the first unequivocal example of successful clinical islet-cell transplantation. © 1990

Cadaveric small bowel and small bowel-liver transplantation in humans

Five patients had complete cadaveric small bowel transplants under FK506 immunosuppression, one as an isolated graft and the other 4 in continuity with a liver. Three were children and two were adults. The five patients are living 2-13 months posttransplantation with complete alimentation by the intestine. The typical postoperative course was stormy, with sluggish resumption of gastrointestinal function. The patient with small intestinal transplantation alone had the most difficult course of the five, including two severe rejections, bacterial and fungal translocation with bacteremia, renal failure with the rejections, and permanent consignment to renal dialysis. The first four patients (studies on the fifth were incomplete) had replacement of the lymphor-eticular cells in the graft lamina propria by their own lymphoreticular cells. Although the surgical and aftercare of these patients was difficult, the eventual uniform success suggests that intestinal transplantation has moved toward becoming a practical clinical service. © 1992 by Williams and Wilkins

Enhancement of pigmeat quality by altering pre-slaughter management

End of project reportThe studies presented in this report were conducted to investigate the effect of breed, slaughter weight, castration of male pigs and strategic feeding strategies on the performance of pigs to slaughter and on their carcass quality. The effect of breed, gender and feeding regimen on the performance of pigs and their carcass quality was examined in the first study (Section 3). From weaning to slaughter Landrace-sired pigs grew at a similar rate but had a better feed conversion efficiency compared with Duroc-sired pigs. Landrace-sired pigs also had a higher carcass lean and greater muscle depth than Duroc-sired pigs. Entire male pigs grew more efficiently, had lower lean content in their carcasses and had a reduced kill out yield when compared with gilts. The eye muscle depth was greater for gilts than entire males. Diluting the diet with grass-meal (GM) reduced growth rate, caused a deterioration in feed conversion efficiency, reduced back fat thickness, reduced eye muscle thickness and reduced kill out yield compared to the control feeding regimen of a cereal based diet. Compensatory growth was observed during a re-alimentation period following a period of diet dilution with grass-meal. However, where it did occur, in most cases it was only partial. Adding 5% rapeseed oil instead of lard to the finisher diet increased nitrogen utilization efficiency and phosphorous utilization efficiency. The effect of gender (boar, castrate, gilt) and slaughter weight (80 to 120kg) on pig performance, carcass quality, meat quality, and nitrogen excretion was investigated in the second study (Section 4). Boars grew faster than gilts and more efficiently than castrates or gilts. Castrates had a higher kill out yield than boars. Nitrogen excretion from castrates was similar to gilts which were both higher than that from boars. The processing value of carcasses from castrates may be higher than that of boars and gilts. In particular castrates had heavier loins and bellies than either boars or gilts. Carcasses from castrates and gilts had a higher temperature (recorded 24 hours post slaughter) than boars. However, pH24 was not affected by gender. The intramuscular fat content of the l. dorsi in castrates was higher than that of boars or gilts, however at 1.65% this was well below the level (2.0%) above which any noticeable sensory attributes might be detected. Feed intake increased with increasing slaughter weight and feed conversion efficiency deteriorated. N excretion also increased with each increment in weight. Carcass lean content increased up to 90kg live EOP 4939.doc 4 25/10/2005 weight then reached a plateau and declined after 110kg live weight. Heavier carcasses yielded more product for approximately the same slaughtering cost and the associated larger muscles could make it easier to use seam butchery techniques that result in lean, well-trimmed, attractive cuts and joints. The pH45 and pH24 were reduced with increasing slaughter weight and drip loss increased. Heavier pigs may be more prone to the development of PSE than lighter pigs as their carcass temperature remains higher for longer than that of lighter pigs

Grouping strategies and lead factors for ration formulation in milking ewes of the Chios breed

The aim of this study was to develop an efficient strategy for ration formulation for milking ewes of the Chios breed in Greece. The strategy involved two and three groupings according to production level and challenge feeding using lead factors. Lead factors, that adjust upwards the average production of a flock or a group of ewes, were calculated for the 83rd and the 90th percentile, using 49,237 milk test-day records from 549 flock-test-days, referring to 64 flocks and 97 complete lactations. Lead factors were 1.25 for the single-group, 1.14 and 1.17 for the two-group, and 1.11, 1.07 and 1.15 for the three-group strategy for the 83rd percentile. Regarding the 90th percentile, these were: 1.33 for the single-group, 1.18 and 1.19 for the two-group, and 1.15, 1.09 and 1.16 for the three-group strategy. Analysis of variance was used to assess the influence of several effects on lead factors. Flock-year and mean and standard deviation milk yield were significant (P250 kg of milk/ewe/year) and low (</p

Le cotonnier sans gossypol, une source de protéines alimentaires. Situation actuelle et perspectives d'avenir, après le colloque d'Abidjan

Commentaires sur le colloque de novembre 1985 à Abidjan. Conditions de la culture de cotonniers sans glandles, intérêt des dérivés des graines sans gossypol en alimentation des animaux et surtout en alimentation humaine, problèmes économiques et commerciaux à résoudr