PERCEPTION OF NARRATIVE MEDICINE AMONG MEDICAL STUDENTS IN LEBANON

The physician-patient relationship has evolved over the years. A good relationship necessitates mutual commitment from both parties, and narrative medicine can be considered as a tool that can aid in improving this relationship, as it helps to improve listening to patients’ stories and turning the patients’ subjective words into objective information, which help physicians to understand the nature of patients’ illnesses, improve the quality of patient care and leads to a better therapeutic effect. A descriptive cross-sectional study was planned. Data collection was done via convenience sampling. Beirut Arab University medical students were asked to fill a paper-based questionnaire between ­­­­­August 2019 and February 2020. The study collected demographic information about the participants including the age, the gender, current academic year, and the cumulative grade point average, and assessed their knowledge about narrative medicine and its importance to be implemented in the medical school curriculum. Data were collected, entered, and analyzed on SPSS software version 23.1. 361 medical students participated. Around 60% thought that narrative medicine helps to promote reflection and empathy, and 80% thought that narrative medicine is essential for enhancing the quality of patient care and that listening to patients’ stories would enhance physician-patient communication. Females tended to have a better understanding of narrative medicine’s importance. The majority agreed that narrative medicine should be an integral part of the medical school curriculum. Medical students were found to be lacking adequate knowledge about narrative medicine. However, the majority agreed on the need for implementation of humanity courses in the current curriculum

Air-classified faba bean protein fraction as a substitute to soybean meal in pelleted and extruded broiler diets

publishedVersio

Fordøyelsesdynamikk av stivelse i slaktekylling : effekt av strukturelle komponenter, stivelsesegenskaper og inklusjonsnivå

Quantitatively, starch is the most important component and the major energy source in poultry diets. Although it is commonly believed that the broiler chicken has a large capacity to digest starch, numerous studies have demonstrated that starch digestibility in some cereal grains or legumes is in some cases suboptimal. In general, starch properties, processing method, inclusion level and the functionality of the gastro-intestinal tract have been considered factors affecting starch utilisation in poultry. To optimise all these factors, a better understanding of the mechanisms explaining the better starch utilisation in broilers is required. Thus, three experiments were conducted to study how gizzard function, starch inclusion level and different starch characteristics affect starch digestion dynamics in broilers. In experiment 1, male broiler chickens were distributed to 48 cages (2 birds each) and given a wheat-based (WB) pelleted diet containing either coarse oat hulls or fine cellulose until d 19 to stimulate divergent development of the gizzard. Thereafter, both groups were further subdivided and challenged with a WB diet containing cellulose in either pelleted or extruded form on d 20 and 22. Either excreta or intestinal contents were collected at time intervals after feeding and analysed for digestibility marker and starch. Thus, in paper I, the hypothesis tested was that a rapid passage of digesta (caused by suboptimal gizzard function) will impair intestinal wheat starch (WS) digestibility when the starch has a low degree of gelatinisation (i.e. in pelleted diets). However, this problem can be alleviated by stimulating gizzard function or by increasing starch gelatinisation through extrusion. Results from paper I showed that starch degradation rate is associated with the flow of digesta, which is linked to gizzard development. In Addition, compared to gelatinised starch, enzymatic hydrolysis of intact starch granules may be limited with more rapid feed passage through the gut. In experiment 2, mixed-sex broilers in 12 replicate pens were given isocaloric and isonitrogenous WB pelleted diets with either a high ratio of starch: fat (HRSF) or a low ratio of starch: fat (LRSF). The diets were formulated by replacing the isolated wheat-starch (WS) in the HRSF by an isocaloric mixture of rapeseed oil and sand in the LRSF. At d 17, the birds were challenged with Eimeria sp. in the drinking water to predispose them to intestinal proliferation of Clostridium perfringens. Ileal samples were collected on d 16 and 29. Thus, in paper II, the hypothesis tested was that a HRSF would impair starch digestibility compared to a LRSF particularly after intestinal infection. Contrary to our hypothesis, a lower ileal starch digestibility was observed in birds given the LRSF compared with the HRSF. The very low fat content in the HSFR increased the friction in the pellet press, resulting in unintended higher pellet temperature and starch gelatinisation degree compared to the LSFR. For this reason, and due to the use of isolated WS (fine texture) in the HRSF, our data cannot be used to reject our hypothesis. Further work is required to clarify this research question, taking into consideration the potentially confounding roles of feed processing and physical form of starch sources. In experiment 3, male broilers were distributed among four dietary treatments consisting of either wheat or faba bean as starch sources, and pelleting or extrusion as processing methods. The wheat (W) and the dehulled faba bean were finely ground using a pin mill. Subsequently, the faba bean was subjected to air classification to produce a faba bean starch-rich fraction (FBS). The WS or FBS was the sole starch source in the diets. Each dietary treatment was fed to 10 replicate pens. Thus, in paper III, the hypothesis tested was that in pelleted diets, legume starch will be more slowly digested compared to cereal starch. However, extrusion will reduce the difference in starch digestion rate and extent between the two sources. The hypothesis of the beneficial effects of a slow starch digestion or a low ratio of starch to nitrogen disappearance rate (SNDR) on broiler performance was also tested. Starch digestibility in the W was very high and similar regardless of the processing method. FBS was highly digestible, however, when used in pelleted diets, it had a lower digestibility and a slower disappearance rate compared to the W in all intestinal segments. The differences in digestibility between the WS and FBS were reduced with extrusion, resulting in an interaction between starch source and processing method. Neither feeding slowly digestible starch nor a lower ratio of SNDR improved feed conversion efficiency. Overall, stimulating gizzard activity improves small intestinal functionality, i.e. starch digestibility, through a better digesta flow regulation. In other words, enzymatic hydrolysis of ungelatinised or large starch particles may be limited with more rapid feed passage to the small intestine. Fine grinding or a high degree of starch gelatinisation can overcome the resistant structural organisation of starch granules, increase enzyme accessibility and improve starch digestibility independent of the starch source, inclusion levels or gizzard function. Enzyme production and glucose absorption do not appear to be major limiting factors to the starch digestion process in broiler chickens. Accelerating starch digestion (or a high ratio of SNDR) had no detrimental effect on the growth performance of the birds, indicating that this hypothesis remains questionable.Kvantitativt er stivelse den viktigste komponenten og hovedkilden til energi i fjørfe-dietter. Selv om det vanligvis antas at broilerkyllingen har stor kapasitet til å fordøye stivelse, har mange studier vist at stivelsesfordøyeligheten av noen korn- og belgvekster i noen tilfeller er suboptimal, og at variasjonen mellom individuelle kyllinger kan være betydelig. Generelt har ulike stivelsesegenskaper, behandlingsmetode, inkluderingsnivå og funksjonalitet i tarmkanalen blitt vurdert som faktorer som påvirker stivelsesutnyttelsen hos fjørfe. For å oppnå en bedre stivelseutnyttelse hos broilere, kreves det en bedre forståelse av mekanismene bak alle disse faktorene. Det har derfor blitt utført tre kyllingforsøk for å studere kråsfunksjonen, stivelsesnivå i dietten og hvordan forskjellige stivelsestyper påvirker fordøyelsesdynamikken til stivelse i broilerkyllinger. I eksperiment 1 ble hanekyllinger fordelt på 48 bur (2 kyllinger per bur) og fôret med hvetebaserte pelleterte dietter som inneholdt enten grove havrekli eller fin cellulose fram til dag 19 for å gi ulik stimulering og dermed forskjellig utvikling av kråsen. Deretter ble begge gruppene ytterligere oppdelt og fôret med WB-dietter som inneholdt cellulose i enten pelletert eller ekstrudert form på dag 20 og 22. Tarminnhold og gjødsel ble samlet inn ved ulike tidsintervaller etter fôring og analysert for markør og stivelse. Hypotesen som ble testet i artikkel I, var at en raskere passasje av fôr gjennom tarmen (forårsaket av suboptimal kråsfunksjon) vil redusere fordøyelsen av stivelse i tarmen når stivelsen har en lav grad av gelatinisering (dvs. i pelleterte dietter). Dette problemet kan imidlertid reduseres ved å regulere passasjen av fôret gjennom stimulering av kråsen, eller ved å øke stivelsesgelatiniseringen ved ekstrudering. Resultater fra artikkel I viste at stivelsesnedbrytningshastigheten er assosiert med passasje av fôr gjennom tarmen, knyttet til utviklingen av kråsen. I tillegg sammenlignet med gelatinisert stivelse,at enzymatisk hydrolyse av intakte stivelsesgranuler kan begrenses med raskere fôrpassasje gjennom tarmkanalen. I eksperiment 2 ble kyllinger i 12 replikate binger gitt isokaloriske og isonitrogenholdige WB-pelleterte dietter med enten høy ratio av stivelse: fett (HRSF) eller lav ratio av stivelse: fett (LRSF). Diettene ble formulert ved å erstatte isolert hvetestivelse i HRSF med en blanding av rapsolje og litt sand for å gi samme energiinnhold i LRSF. Ved d 17 ble fuglene utfordret med Eimeria sp i drikkevannet for å predisponere dem for økt vekst av Clostridium perfringens i tarmen. Ilealprøver ble tatt på d 16 og 29. Hypotesen som ble testet i artikkel II var at HRSF ville redusere stivelsesfordøyeligheten, sammenlignet med LRSF, spesielt etter en tarminfeksjon. Men i motsetning til vår hypotese ble det observert en lavere ileal stivelsesfordøyelighet hos kyllinger fôret med LRSF, sammenlignet med HRSF. På grunn av det svært lave fettinnholdet i HSFR økte friksjonen i pelletspressen, noe som resulterte i utilsiktet høyere pelletstemperatur og grad av stivelsesgelatinisering sammenlignet med LSFR. Av denne grunn, og på grunn av bruk av isolert stivelse (fin tekstur) i HRSF, kan ikke dataene våre brukes til å avvise hypotesen. Ytterligere arbeid er nødvendig for å klargjøre dette forskningsspørsmålet, tatt i betraktning de potensielt motstridende resultatene m.h.t. fôrprosessering og ulike fysiske former av stivelse. I eksperiment 3, ble hanekyllinger fordelt på fire diettbehandlinger som bestod av enten hvete eller fababønner som stivelseskilder, og pelletering eller ekstrudering som behandlingsmetoder. Avskallede fababønner ble finmalt og luftklassifisert for å produsere en stivelsesrik fababønne-fraksjon (FBS), mens hveten (WS) ble finmalt før bruk. WS eller FBS var den eneste stivelseskilden i dietten. Hver diettbehandling ble fôret til 10 replikate binger. Hypotesen som ble testet i artikkel III, var at stivelse fra legumer vil bli saktere fordøyd, sammenlignet med stivelse fra korn, når gelatiniseringsgraden er lav (pelleterte dietter). Økning av gelatiniseringsgraden v.h.a. ekstrudering vil imidlertid redusere forskjellen i fordøyelseshastighet og omfang mellom de to stivelsekildene. Hypotesen om at saktere fordøyelse av stivelse, eller en lav ratio mellom stivelse- og nitrogen-fordøyelse (SNDR), ville gi fordelaktige effekter på veksten og fôrutnyttelsen hos kyllinger, ble også testet. Stivelsesfordøyeligheten av WS var veldig høy, og lignende for begge prosesseringsmetodene. FBS var svært fordøyelig, imidlertid når den ble brukt i pelleterte fôr hadde den lavere fordøyelighet og ble tatt opp langsommere opp fra alle segmentene i tynntarmen sammenlignet med WS. Forskjellene mellom WS og FBS ble redusert med ekstrudering, noe som resulterte i en interaksjon mellom stivelseskilde og prosesseringsmetode. Fôring med sakte fordøyelig stivelse forbedret ikke fôrkonverteringseffektiviteten, og heller ikke en lavere ratio av SNDR. Generelt kan det konkluderes at ved økt stimulering av kråsaktiviteten forbedres tarmfunksjonen i tynntarmen, dvs. stivelsesfordøyeligheten, gjennom en bedre regulering av hastigheten til fôret som kommer til tarmen. Med andre ord kan enzymatisk hydrolyse av ugelatinisert eller store stivelsespartikler begrenses med for rask tilførsel av fôr som passerer gjennom tynntarmen. Fin malingsgrad eller høyere grad av stivelsesgelatinisering kan motvirkeden resistente strukturelle organisasjonen av stivelsesgranulater, øke enzymtilgjengeligheten og forbedre stivelsesfordøyeligheten, uavhengig av stivelseskilden, inkluderingsnivåer eller kråsfunksjon. Enzymproduksjon og glukoseabsorpsjon ser ikke ut til å være en stor begrensende faktorer for stivelsesfordøyelsesprosessen hos slaktekyllinger. Raskere stivelsefordøyelse (eller en høy ratio av SNDR) hadde ingen negativ effekt på vekstytelsen hos slaktekylling, noe som indikerer at denne hypotesen ikke kan bekreftes

Intestinal Passage and Its Relation to Digestive Processes

Despite an effective nutrient retention, impaired digestibility is frequently observed. This review aims to give an overview of retention time of material through the digestive tract in an attempt to reveal mechanisms relating flow and retention of material to the digestive process. The mean retention time based on marker content in the different segments of the digestive tract or measured as time of 50% marker excreted is remarkably short at between 5 and 6 h, but varies considerably due to method used, diet composition, and feeding pattern. Mean retention time in the small intestine is commonly reported to be around 3 h, with 1 h retention time in the tract proximal to Meckel’s diverticulum, and is less affected by diet or feeding pattern. The mechanism explaining a high nutrient digestion and absorption despite this astonishingly short timeisstillapuzzle.Aselectiveflowandrefluxofmaterialthroughoutthesmallintestineseems to be a potential mechanism, but more research is needed in this important and fascinating area of poultry research.acceptedVersio

Feed processing and structural components affect starch digestion dynamics in broiler chickens

1. A 2 × 2 factorial design was used to test the hypothesis that impaired intestinal starch digestibility is attributable to rapid passage of digesta from the gizzard to the intestine, and that, compared to steam pelleting, increasing the availability of starch through extrusion cooking may alleviate the potential negative effect of rapid digesta flow on starch utilisation. 2. Thus, 7-d-old-broiler chickens were distributed to 48 cages and given a wheat-based (WB) pelleted diet containing either coarse oat hulls (OH-Pel) or fine cellulose (Cel-Pel) until d 19 to stimulate divergent development of the gizzard. Thereafter, both groups were further subdivided and challenged with a WB diet containing cellulose in either pelleted (Cel-Pel) or extruded (Cel-Ext) form on d 20 and 22. Either excreta or intestinal contents were collected at time intervals after feeding and analysed for marker and starch. 3. OH-Pel increased gizzard size and holding capacity. No excessively high starch levels (maximum 25 g/kg) were detected in the excreta. However, 8 h feed-deprived birds given Cel-Pel and challenged with Cel-Pel exhibited higher starch excretion and showed large individual variation during the first 135 min of collection. 4. Contrary to the OH-Pel group, more digesta and starch passed to the jejunum at 1 and 2 h and ileum at 2 and 3 h after feeding for birds given Cel-Pel, resulting in lower jejunal and ileal starch digestibility. 5. Increased starch gelatinisation through extrusion processing significantly improved starch digestibility regardless of gizzard function. However, at 1, 2 and 3 h after feeding, more digesta was retained in the foregut of birds given Cel-Ext. 6. The current data showed that starch degradation rate is associated with the flow of digesta which is linked to gizzard development, and that enzymatic hydrolysis of intact starch granules may be limited with more rapid feed passage through the gut.acceptedVersio

Eating patterns of broiler chickens fed insoluble grit, and its effect on intake variation, retention time, performance and gizzard development

In a field trial, the current study tested the effects of insoluble granite grit stones supplemented to broiler chickens on growth performance and gizzard stimulation. Particle size distribution and variation in the amount of grit retained in the gizzards were also examined at different age intervals. 880-day-old broiler chicks were allocated randomly and equally to 11 floor pens and maintained on a commercial pelleted diet. The trial consisted of two treatments: a control, or no-grit group (NGG), and a grit treatment group (GG). During the first three days, all pens were managed under the same conditions. On day four, chicks in the GG were given grit stones (sieved to a size range of 3.55 to 1.6mm) on separate plates. Grit provision was initiated with 150 grams per pen, and continued on days seven, nine and eleven respectively with 350g per pen, making 1200g in total or 15g per bird. On day 18, uneaten grit was withdrawn from all pens. At 10, 21 and 28 days, randomly selected grit-fed birds were killed and frozen for laboratory analysis. At 30 days of age, 208 gizzards from both groups (416 in total) were collected from the slaughter house. 72 gizzards from the 208 were randomly selected to examine the variation in the amount of grit retained at the end of the trial. Finally, grit from the rest of the gizzards was pooled in one sample and analyzed for particle distribution. The findings showed grit supplementation did not impair nor improve (P > 0.05) broiler overall performance compared to the NGG. Grit significantly increased (P < 0.001) gizzards' size, and their full and empty weight in the grit-fed birds. Birds from the GG showed individuality in the amount of grit ingested at different ages and the variation in the amount retained increased with age. Grit seemed to be evenly distributed among gizzard contents, which provided more contact surface with the feed and efficient particles grinding. On average, grit accounted for almost 36% of the total gizzard content weight at 10 and 21 days, but dropped to 21% at 28 days of age. Retained grit varied from zero to 368 particles. Of the 208 gizzards, 8% retained nil, and 3% contained very few, whereas the remainder retained a considerable amount even 12 days after withdrawal. The average number of stones found in the gizzards was 161, 231 and 140 stones, while the maximum amounts were 243, 366 and 368 stones at 10, 21 and 28 days respectively. It was observed in the small intestine that some grit of different sizes were passing through the gizzard almost completely intact during various growth periods. Gizzard grit appeared to have smoother surfaces with rounded corners due to erosion as opposed to the rough, irregular and sharp edges of the initial grit. Particle size distribution showed a conspicuous reduction in larger particle proportion and a subsequent increase in the medium and small particles fraction

Energy recovery for integrated wheel-motor, electric vehicle application

Le sujet de thèse aborde la quantification du flux de puissance parcourant les différents systèmes de conversion d'énergie statiques et dynamiques pour aboutir aux éléments de stockage de nature chimique / électrostatique / mécanique lors d'un freinage hybride récupératif brusque issu d’un véhicule électrique à traction avant. Le véhicule électrique est équipé de deux ensembles intégrés moteur-roues indépendants. Le côté commande des convertisseurs et des machines électriques sera aussi traité. La problématique concernera les cas de freinage régénératif brusque imposant des contraintes électriques et mécaniques élevées aux éléments de conversion d'énergie et de stockage. L'outil de simulation adopté est le logiciel Matlab/Simulink®. Un modèle assez fin du véhicule électrique utilisé sera développé afin de pouvoir simuler le comportement du véhicule conformément à la distribution des forces de freinage délivrée par le système de répartition et de quantification des forces de freinage. Une étude de la cinématique et de la dynamique du véhicule selon les différents états de route sera aussi examiné. Cette étude sera utilisée à posteriori dans la formulation des lois de distribution des forces de freinage. Les moteurs utilisés sont de type synchrones à aimants permanents intérieurs. L'objectif est d'assurer un couple électrique de freinage élevé à hautes vitesses de conduite du véhicule. A cette fin, la commande optimale de ces moteurs sera basée sur une nouvelle méthode de génération des courants de références assumant ainsi un couple régénératif élevé et donc une amélioration de l'énergie récupérée. Le système de stockage sera mixte et comportera une batterie Li-Ion et des cellules de supercondensateurs afin de réduire les contraintes sur la batterie et prolonger ainsi sa durée de vie. La structure de puissance de ce système sera analysée ainsi que le système de commande proposé du hacheur à 3 niveaux interfaçant l'ultracapacité avec le bus DC. Une résistance de freinage commandée par un régulateur pseudo-cascade sera aussi intégrée afin de réduire, si nécessaire, les contraintes sur la batterie. L'évaluation et la répartition des forces de freinage sur les quatre roues du véhicule en fonction de l'état de la route sont des éléments clés pour la stabilité du véhicule lors du freinage. La méthode de distribution et de quantification des forces de freinage proposée devra maintenir cette stabilité, répondre aux normes internationales et tirer profit de la présence des moteur-roues à l'avant du véhicule afin de maximiser l'énergie récupérée. Les travaux ont été étendus pour inclure une étude comparative avec un système de stockage contenant un élément de stockage à énergie cinétique comme source d'énergie secondaire pour un véhicule en opération de freinage et de traction. La thèse est le point de départ d'une collaboration de recherche entre l'IFSTTAR /Satie et le département de Génie Electrique du Cnam - Liban, centre associé au Conservatoire National des Arts et Métiers (Paris - France).The thesis will address the quantification of power flow going through the different energy static and dynamic conversion systems to attain the chemical / electrostatic / mechanical storage elements during a hybrid regenerative brutal braking of a front-wheel driven electric vehicle. The electric vehicle is equipped by two integrated wheel-motors independent sets. The control of the converters and electrical machines is also treated. The problematic concerns the brutal regenerative braking case imposing high electrical and mechanical constraints on energy conversion and storage elements. The simulation tool adopted is Matlab/Simulink®. A detailed model of the used electric vehicle has been developed in order to be able to simulate the vehicle behavior with respect to the braking forces distribution delivered by the repartition and quantification of braking forces system. A study of the kinematics and dynamics of the vehicle according to different road types will be also considered. This study will be used retrospectively in the formulation of the braking forces distribution laws. The motors used are interior permanent magnet synchronous type. The objective is to ensure high electrical braking torque at high driving speeds of the vehicle. To this end, the optimal control of these motors will be based on a new current references generation method assuming then a high regenerative torque and therefore an improvement in the recovered energy. The hybrid storage system includes a Li-Ion battery and supercapacitors cells to reduce stress on the battery and to extend its life. The power structure of the system will be analyzed as well as the 3-level DC/DC converter interfacing the ultracapacitor with the DC bus proposed control system. A braking resistor controlled by a pseudo- cascaded controller will also be integrated to reduce, if necessary, the constraints on the battery. The evaluation and distribution of braking forces on the four wheels depending on road conditions are key elements for the stability of the vehicle during braking. The method of distribution and quantification of braking forces proposed should maintain this stability , meet international standards and take advantage of the presence of wheel motors in the front of the vehicle to maximize the energy recovered. The work has been extended to include a comparative study with a system containing a kinetic energy storage element as a secondary energy source for a braking and traction vehicle operation. The thesis is the starting point of a research collaboration between IFSTTAR / Satie and the Electrical Engineering Department of Cnam- Liban, associated center of the Conservatoire National des Arts et Métiers ( CNAM ), Paris, France

Starch digestion dynamics in broiler chickens as affected by structural components, starch properties and level of inclusion

Quantitatively, starch is the most important component and the major energy source in poultry diets. Although it is commonly believed that the broiler chicken has a large capacity to digest starch, numerous studies have demonstrated that starch digestibility in some cereal grains or legumes is in some cases suboptimal. In general, starch properties, processing method, inclusion level and the functionality of the gastro-intestinal tract have been considered factors affecting starch utilisation in poultry. To optimise all these factors, a better understanding of the mechanisms explaining the better starch utilisation in broilers is required. Thus, three experiments were conducted to study how gizzard function, starch inclusion level and different starch characteristics affect starch digestion dynamics in broilers. In experiment 1, male broiler chickens were distributed to 48 cages (2 birds each) and given a wheat-based (WB) pelleted diet containing either coarse oat hulls or fine cellulose until d 19 to stimulate divergent development of the gizzard. Thereafter, both groups were further subdivided and challenged with a WB diet containing cellulose in either pelleted or extruded form on d 20 and 22. Either excreta or intestinal contents were collected at time intervals after feeding and analysed for digestibility marker and starch. Thus, in paper I, the hypothesis tested was that a rapid passage of digesta (caused by suboptimal gizzard function) will impair intestinal wheat starch (WS) digestibility when the starch has a low degree of gelatinisation (i.e. in pelleted diets). However, this problem can be alleviated by stimulating gizzard function or by increasing starch gelatinisation through extrusion. Results from paper I showed that starch degradation rate is associated with the flow of digesta, which is linked to gizzard development. In Addition, compared to gelatinised starch, enzymatic hydrolysis of intact starch granules may be limited with more rapid feed passage through the gut. In experiment 2, mixed-sex broilers in 12 replicate pens were given isocaloric and isonitrogenous WB pelleted diets with either a high ratio of starch: fat (HRSF) or a low ratio of starch: fat (LRSF). The diets were formulated by replacing the isolated wheat-starch (WS) in the HRSF by an isocaloric mixture of rapeseed oil and sand in the LRSF. At d 17, the birds were challenged with Eimeria sp. in the drinking water to predispose them to intestinal proliferation of Clostridium perfringens. Ileal samples were collected on d 16 and 29. Thus, in paper II, the hypothesis tested was that a HRSF would impair starch digestibility compared to a LRSF particularly after intestinal infection. Contrary to our hypothesis, a lower ileal starch digestibility was observed in birds given the LRSF compared with the HRSF. The very low fat content in the HSFR increased the friction in the pellet press, resulting in unintended higher pellet temperature and starch gelatinisation degree compared to the LSFR. For this reason, and due to the use of isolated WS (fine texture) in the HRSF, our data cannot be used to reject our hypothesis. Further work is required to clarify this research question, taking into consideration the potentially confounding roles of feed processing and physical form of starch sources. In experiment 3, male broilers were distributed among four dietary treatments consisting of either wheat or faba bean as starch sources, and pelleting or extrusion as processing methods. The wheat (W) and the dehulled faba bean were finely ground using a pin mill. Subsequently, the faba bean was subjected to air classification to produce a faba bean starch-rich fraction (FBS). The WS or FBS was the sole starch source in the diets. Each dietary treatment was fed to 10 replicate pens. Thus, in paper III, the hypothesis tested was that in pelleted diets, legume starch will be more slowly digested compared to cereal starch. However, extrusion will reduce the difference in starch digestion rate and extent between the two sources. The hypothesis of the beneficial effects of a slow starch digestion or a low ratio of starch to nitrogen disappearance rate (SNDR) on broiler performance was also tested. Starch digestibility in the W was very high and similar regardless of the processing method. FBS was highly digestible, however, when used in pelleted diets, it had a lower digestibility and a slower disappearance rate compared to the W in all intestinal segments. The differences in digestibility between the WS and FBS were reduced with extrusion, resulting in an interaction between starch source and processing method. Neither feeding slowly digestible starch nor a lower ratio of SNDR improved feed conversion efficiency. Overall, stimulating gizzard activity improves small intestinal functionality, i.e. starch digestibility, through a better digesta flow regulation. In other words, enzymatic hydrolysis of ungelatinised or large starch particles may be limited with more rapid feed passage to the small intestine. Fine grinding or a high degree of starch gelatinisation can overcome the resistant structural organisation of starch granules, increase enzyme accessibility and improve starch digestibility independent of the starch source, inclusion levels or gizzard function. Enzyme production and glucose absorption do not appear to be major limiting factors to the starch digestion process in broiler chickens. Accelerating starch digestion (or a high ratio of SNDR) had no detrimental effect on the growth performance of the birds, indicating that this hypothesis remains questionable

Récupération d’énergie pour système intégré moteur roue, application au véhicule électrique

The thesis will address the quantification of power flow going through the different energy static and dynamic conversion systems to attain the chemical / electrostatic / mechanical storage elements during a hybrid regenerative brutal braking of a front-wheel driven electric vehicle. The electric vehicle is equipped by two integrated wheel-motors independent sets. The control of the converters and electrical machines is also treated. The problematic concerns the brutal regenerative braking case imposing high electrical and mechanical constraints on energy conversion and storage elements. The simulation tool adopted is Matlab/Simulink®. A detailed model of the used electric vehicle has been developed in order to be able to simulate the vehicle behavior with respect to the braking forces distribution delivered by the repartition and quantification of braking forces system. A study of the kinematics and dynamics of the vehicle according to different road types will be also considered. This study will be used retrospectively in the formulation of the braking forces distribution laws. The motors used are interior permanent magnet synchronous type. The objective is to ensure high electrical braking torque at high driving speeds of the vehicle. To this end, the optimal control of these motors will be based on a new current references generation method assuming then a high regenerative torque and therefore an improvement in the recovered energy. The hybrid storage system includes a Li-Ion battery and supercapacitors cells to reduce stress on the battery and to extend its life. The power structure of the system will be analyzed as well as the 3-level DC/DC converter interfacing the ultracapacitor with the DC bus proposed control system. A braking resistor controlled by a pseudo- cascaded controller will also be integrated to reduce, if necessary, the constraints on the battery. The evaluation and distribution of braking forces on the four wheels depending on road conditions are key elements for the stability of the vehicle during braking. The method of distribution and quantification of braking forces proposed should maintain this stability , meet international standards and take advantage of the presence of wheel motors in the front of the vehicle to maximize the energy recovered. The work has been extended to include a comparative study with a system containing a kinetic energy storage element as a secondary energy source for a braking and traction vehicle operation. The thesis is the starting point of a research collaboration between IFSTTAR / Satie and the Electrical Engineering Department of Cnam- Liban, associated center of the Conservatoire National des Arts et Métiers ( CNAM ), Paris, France.Le sujet de thèse aborde la quantification du flux de puissance parcourant les différents systèmes de conversion d'énergie statiques et dynamiques pour aboutir aux éléments de stockage de nature chimique / électrostatique / mécanique lors d'un freinage hybride récupératif brusque issu d’un véhicule électrique à traction avant. Le véhicule électrique est équipé de deux ensembles intégrés moteur-roues indépendants. Le côté commande des convertisseurs et des machines électriques sera aussi traité. La problématique concernera les cas de freinage régénératif brusque imposant des contraintes électriques et mécaniques élevées aux éléments de conversion d'énergie et de stockage. L'outil de simulation adopté est le logiciel Matlab/Simulink®. Un modèle assez fin du véhicule électrique utilisé sera développé afin de pouvoir simuler le comportement du véhicule conformément à la distribution des forces de freinage délivrée par le système de répartition et de quantification des forces de freinage. Une étude de la cinématique et de la dynamique du véhicule selon les différents états de route sera aussi examiné. Cette étude sera utilisée à posteriori dans la formulation des lois de distribution des forces de freinage. Les moteurs utilisés sont de type synchrones à aimants permanents intérieurs. L'objectif est d'assurer un couple électrique de freinage élevé à hautes vitesses de conduite du véhicule. A cette fin, la commande optimale de ces moteurs sera basée sur une nouvelle méthode de génération des courants de références assumant ainsi un couple régénératif élevé et donc une amélioration de l'énergie récupérée. Le système de stockage sera mixte et comportera une batterie Li-Ion et des cellules de supercondensateurs afin de réduire les contraintes sur la batterie et prolonger ainsi sa durée de vie. La structure de puissance de ce système sera analysée ainsi que le système de commande proposé du hacheur à 3 niveaux interfaçant l'ultracapacité avec le bus DC. Une résistance de freinage commandée par un régulateur pseudo-cascade sera aussi intégrée afin de réduire, si nécessaire, les contraintes sur la batterie. L'évaluation et la répartition des forces de freinage sur les quatre roues du véhicule en fonction de l'état de la route sont des éléments clés pour la stabilité du véhicule lors du freinage. La méthode de distribution et de quantification des forces de freinage proposée devra maintenir cette stabilité, répondre aux normes internationales et tirer profit de la présence des moteur-roues à l'avant du véhicule afin de maximiser l'énergie récupérée. Les travaux ont été étendus pour inclure une étude comparative avec un système de stockage contenant un élément de stockage à énergie cinétique comme source d'énergie secondaire pour un véhicule en opération de freinage et de traction. La thèse est le point de départ d'une collaboration de recherche entre l'IFSTTAR /Satie et le département de Génie Electrique du Cnam - Liban, centre associé au Conservatoire National des Arts et Métiers (Paris - France)

Récupération d’énergie pour système intégré moteur roue, application au véhicule électrique

The thesis will address the quantification of power flow going through the different energy static and dynamic conversion systems to attain the chemical / electrostatic / mechanical storage elements during a hybrid regenerative brutal braking of a front-wheel driven electric vehicle. The electric vehicle is equipped by two integrated wheel-motors independent sets. The control of the converters and electrical machines is also treated. The problematic concerns the brutal regenerative braking case imposing high electrical and mechanical constraints on energy conversion and storage elements. The simulation tool adopted is Matlab/Simulink®. A detailed model of the used electric vehicle has been developed in order to be able to simulate the vehicle behavior with respect to the braking forces distribution delivered by the repartition and quantification of braking forces system. A study of the kinematics and dynamics of the vehicle according to different road types will be also considered. This study will be used retrospectively in the formulation of the braking forces distribution laws. The motors used are interior permanent magnet synchronous type. The objective is to ensure high electrical braking torque at high driving speeds of the vehicle. To this end, the optimal control of these motors will be based on a new current references generation method assuming then a high regenerative torque and therefore an improvement in the recovered energy. The hybrid storage system includes a Li-Ion battery and supercapacitors cells to reduce stress on the battery and to extend its life. The power structure of the system will be analyzed as well as the 3-level DC/DC converter interfacing the ultracapacitor with the DC bus proposed control system. A braking resistor controlled by a pseudo- cascaded controller will also be integrated to reduce, if necessary, the constraints on the battery. The evaluation and distribution of braking forces on the four wheels depending on road conditions are key elements for the stability of the vehicle during braking. The method of distribution and quantification of braking forces proposed should maintain this stability , meet international standards and take advantage of the presence of wheel motors in the front of the vehicle to maximize the energy recovered. The work has been extended to include a comparative study with a system containing a kinetic energy storage element as a secondary energy source for a braking and traction vehicle operation. The thesis is the starting point of a research collaboration between IFSTTAR / Satie and the Electrical Engineering Department of Cnam- Liban, associated center of the Conservatoire National des Arts et Métiers ( CNAM ), Paris, France.Le sujet de thèse aborde la quantification du flux de puissance parcourant les différents systèmes de conversion d'énergie statiques et dynamiques pour aboutir aux éléments de stockage de nature chimique / électrostatique / mécanique lors d'un freinage hybride récupératif brusque issu d’un véhicule électrique à traction avant. Le véhicule électrique est équipé de deux ensembles intégrés moteur-roues indépendants. Le côté commande des convertisseurs et des machines électriques sera aussi traité. La problématique concernera les cas de freinage régénératif brusque imposant des contraintes électriques et mécaniques élevées aux éléments de conversion d'énergie et de stockage. L'outil de simulation adopté est le logiciel Matlab/Simulink®. Un modèle assez fin du véhicule électrique utilisé sera développé afin de pouvoir simuler le comportement du véhicule conformément à la distribution des forces de freinage délivrée par le système de répartition et de quantification des forces de freinage. Une étude de la cinématique et de la dynamique du véhicule selon les différents états de route sera aussi examiné. Cette étude sera utilisée à posteriori dans la formulation des lois de distribution des forces de freinage. Les moteurs utilisés sont de type synchrones à aimants permanents intérieurs. L'objectif est d'assurer un couple électrique de freinage élevé à hautes vitesses de conduite du véhicule. A cette fin, la commande optimale de ces moteurs sera basée sur une nouvelle méthode de génération des courants de références assumant ainsi un couple régénératif élevé et donc une amélioration de l'énergie récupérée. Le système de stockage sera mixte et comportera une batterie Li-Ion et des cellules de supercondensateurs afin de réduire les contraintes sur la batterie et prolonger ainsi sa durée de vie. La structure de puissance de ce système sera analysée ainsi que le système de commande proposé du hacheur à 3 niveaux interfaçant l'ultracapacité avec le bus DC. Une résistance de freinage commandée par un régulateur pseudo-cascade sera aussi intégrée afin de réduire, si nécessaire, les contraintes sur la batterie. L'évaluation et la répartition des forces de freinage sur les quatre roues du véhicule en fonction de l'état de la route sont des éléments clés pour la stabilité du véhicule lors du freinage. La méthode de distribution et de quantification des forces de freinage proposée devra maintenir cette stabilité, répondre aux normes internationales et tirer profit de la présence des moteur-roues à l'avant du véhicule afin de maximiser l'énergie récupérée. Les travaux ont été étendus pour inclure une étude comparative avec un système de stockage contenant un élément de stockage à énergie cinétique comme source d'énergie secondaire pour un véhicule en opération de freinage et de traction. La thèse est le point de départ d'une collaboration de recherche entre l'IFSTTAR /Satie et le département de Génie Electrique du Cnam - Liban, centre associé au Conservatoire National des Arts et Métiers (Paris - France)