Dissertations / Theses on the topic 'Debond effect'

Numerical simulations and analytical models are increasingly being sought for the design and behaviour prediction of composite materials. The use of high-performance composite materials is a growing area particularly in civilian and defence related applications. This growth demands the understanding and ability to predict how these materials will behave under their exposed environments. In this thesis, the displacement behaviour of naturally debonded composites (NDCs) from out-of-plane bending conditions is investigated. A detailed experimental programme is conducted to ascertain the phenomenological behaviours of these systems from steady-state responses for forced harmonic loading and freevibrations. The stiffness and energy dissipation behaviour are examined and a finite element (FE) model describing their behaviour is developed. Using the FE model, the experimental programme is extended through simulations and analytical models are developed to predict the displacement response behaviour. Through the exploitation of the analytical models, a linearisation is used to extract the bulk effective material properties and a constitutive model is developed to describe multi-layered 0JDCs that are reduced to a single layer describing their steady-state responses. The friction between each of the layers is included in the analytical model and is shown to have distinct behaviour for these types of composites. Acceptable agreement is observed between the analytical model predictions, the FE model and the experiments. It is well known that prevention of failure for vibratory exposed structures is a continuing challenge and that although the characterisation of damping in vibrating structures has long been an active area of research in structural dynamics, it is usually limited to experimental data. As the exploitation of lighter and more efficient structures is becoming more prevalent, the need for alternative damping materials and systems is overwhelmingly necessary. The use of NDCs poses as a viable candidate for rectifying some of these challenges, particularly since they can be designed with high levels of accuracy as opposed to a rough estimation as with many damping systems. From this work it is shown that layered NDCs have the ability to dissipate large amounts of energy from exploiting their frictional interfaces. There are many areas that NDCs could serve to be useful as damping systems.

La sobriété est ce terme polysémique présenté par la recherche académique et les médias comme le scénario incontournable de la transition écologique. Son acception contemporaine englobe une multitude de sens : la frugalité, la tempérance, la simplicité volontaire, qui désignent plusieurs régulations possibles de nos consommations matérielles. Ce travail de thèse instruit et met à l’épreuve la notion de sobriété en s’appuyant sur des enquêtes de terrain qui s’intéressent aux « migrations urbaines de télétravailleurs en ruralité ». Un départ en territoire rural fondé sur des motivations matérialistes et affectives. Nous étudions le rapport subjectif à la consommation et les représentations des idéaux de vie des digitaux-néo-ruraux. Ce néologisme définit cette nouvelle figure du salarié digital à cheval entre plusieurs territoires, entre modernisme et retour à la terre. Nos enquêtes relatent une sobriété expérientielle qui montre plusieurs opérationnalités possibles de ce concept réductionniste : « effet débond », « consommation territorialement responsable », « autre rapport au temps », « sobriété contingente », « hub domestique ». La sobriété dévoile plusieurs facettes à même d’élargir sa désirabilité. L’acculturation est gérée par des stratégies d’intégration où la consommation est utilisée pour légitimer son affiliation territoriale. Notre recherche montre des digitaux-néo-ruraux qui articulent enjeux environnementaux, technologiques, économiques et sociétaux. Ce travail de thèse permet de mieux comprendre la construction d’autres modes et imaginaires de vie avec une logique de l’abondance qui est questionnée
Sufficiency is a polysemous term presented by academic research and the media as the essential scenario for ecological transition. Its contemporary meaning encompasses a multitude of meanings: frugality, temperance, voluntary simplicity, all of which refer to possible ways of regulating our material consumption. This thesis examines and tests the notion of sufficiency by drawing on field research into the 'urban migration of teleworkers'. A move to rural areas based on materialistic and affective motivations.We are studying the subjective relationship to consumption and the representations of the ideals of life of the digital-neo-rural. This neologism defines this new figure of the digital employee straddling several territories, between modernism and a return to the land.Our surveys reveal an experiential sufficiency that shows several possible operationalities of this reductionist concept: "debond effect", "territorially responsible consumption", "another relationship with time", "contingent sufficiency", "domestic hub". Sufficiency has a number of facets that can broaden its desirability. Acculturation is managed by integration strategies in which consumption is used to legitimise territorial affiliation. Our research shows that digital-neo-rural living combines environmental, technological, economic, and societal issues. This thesis provides a better understanding of the construction of alternative lifestyles and imaginaries, with the logic of abundance being called into question

Breast muscles that are deboned prior to 4 to 6 h postmortem are highly variable and lacking in tenderness. The poultry industry currently provides costly storage space for intact broiler breasts during this 4 to 6 h period. This thesis evaluates tenderization techniques that if effective could eliminate the need for this additional 4 to 6 h storage time. The first objective of this study was to determine a relationship between Warner-Bratzler shear values (WBS) (1 cm by 1cm, variable length strips) and consumer tenderness acceptability of broiler breasts. The breasts were divided into five groups based on their WBS values. Consumers were presented with one sample (1 cm by 1 cm by 2 cm strips) at a time and asked to report the acceptability of the sample's tenderness on a 9-point hedonic scale. Of the 62 panelists, 93.5 % found chicken breasts with WBS values from 2.1 to 3.1 kg to be acceptable. Only 83.9 % of the panelists found the extremely tender chicken breast to be acceptable (1.1 to 1.9 kg). The percentage of consumers that found the samples acceptable decreased as the WBS values increased beyond 3.1 kg (P<0.05). The second objective determined the effects of high pressure hydrodynamic shockwave (HSW) on tenderness (48 h postmortem) of early-deboned (52 min postmortem) breasts treated 25 minutes after deboning (70 min postmortem) or treated after storage (24 hr postmortem) and compared to the corresponding non-treated companion breasts. The effect of HSW treatment on early-deboned treated 25 min after deboned broiler breasts was determined by the following methods. Live broiler chickens were obtained from a commercial poultry company and slaughtered according to commercial processing standards. The effect of HSW on early deboned stored broiler breast was examined by deboning broiler breasts 45 min postmortem and storing (4 C) for 24 h. One breast from each bird was treated with hydrodynamic shockwave, while the companion breast was used as a control. Packaged breasts were placed in the center of a 20.23 cm diameter cylinder which was vertically positioned in the bottom of a water-filled HSW hemishell tank (30.4 cm diameter) and a shockwave was produced by and a shockwave was produced by detonating 40 grams of molecular explosive in the water. Early deboned (ED) breasts stored 24 h before treatment (2.5 kg, WBS) were 42% more tender than the companion ED control breasts (4.3 kg, WBS). The HSW treated breasts would be acceptable to approximately 94 % of consumers. The ED control breasts would be acceptable to only 67.7% of consumers. Early deboned and treated 25 min after deboning breasts (5.0 kg) were not different in WBS from their companion ED control breasts (4.6 kg). Early-deboned breasts treated immediately may require higher pressure shockwaves or delayed treatment. The HSW process can overcome the problem with tenderness associated with early deboning if the breasts are processed after storage thereby providing processors with the option to debone earlier. A third objective was to examine the effects of electrically produced shockwaves on early deboned broiler breasts and normally processed turkey breast. Broiler breasts were treated with one Pulse Firing Network (PFN) or two PFN and 45 % Energy. Breasts treated with one PFN were not different than controls. Broiler breasts exposed to two PFN were 22 % more tender and different from the controls. Turkey breast portions exposed to two PFN and 72% Energy were different (12 % lower WBS values) from the control breast portion. Electrically produced shockwaves can tenderize stored, early deboned chicken breasts and aged turkey breasts.
Master of Science

Tissue, among the highest value added paper products, finds extensive application in modern society. Continued efforts are being made to further improve tissue properties, such as strength, softness and water absorbency. Besides the efforts on characterizing facial tissue softness, this study focuses on tissue quality improvement through chemical means. The application of a wet strength resin, Kymene1500 and a debonding agent, Softrite7516 onto cellulose fibers is considered. First, the adsorption kinetics of the two chemical additives onto cellulose fibers was studied. The adsorption mechanisms were proposed and validated by kinetic data. A novel apparatus was designed in this study, and represented the first in the field to collect real-time data, which has the potential to be applied to the adsorption kinetic study of other types of paper additives. Second, the effects of Kymene1500 and Softrite7516 on various sheet properties were studied. The results provide quantitative information on tissue additives effects on sheet properties. It is shown that the combined application of the additives can overcome the disadvantages of individual species and produce sheets with both wet strength and softness. Finally, environmental-benign debonding agents with polyoxyethylene chains were applied to the sheets, and the effects of two design parameters, i.e., fatty acid and degree of ethoxylation, on tissue properties were investigated.

Le présent travail portait sur l'étude des effets de la supplémentation haptique sur la stabilité posturale debout et assise du sujet jeune et âgé. La question si les informations haptiques fournies par un support mobile améliorent la stabilité autant qu'un support fixe a peu été étudiée. Le présent travail visait à contribuer à une meilleure compréhension des mécanismes sous-jacents à l'effet stabilisateur potentiel d'un support type « canne mobile ». Les analyses portaient sur le centre de pression (COP). Les résultats des premières deux études confirment notre hypothèse générale sur l'effet de la supplémentation haptique indépendant de l'âge et de la mobilité du support. Si une résistance suffisante est fournie à l'opposé des oscillations du corps par le support les participants amélioraient leur stabilité. Dans la troisième étude, nous avons également manipulé des entrées visuelles et les résultats suggèrent qu'un manque de vision peut être compensé par la supplémentation. Dans la quatrième étude, nous avons également analysé la coordination inter-segmentaire. Les résultats suggèrent un meilleur contrôle postural avec la supplémentation alors qu'elle n'influence pas la coordination inter-segmentaire. La cinquième étude visait à déterminer si la supplémentation permettait d'améliorer la robustesse du système à des perturbations. Les résultats suggèrent que les sujets jeunes réduisent le temps de la première correction du COP avec la supplémentation alors que les sujets âgés corrigent leur COP plus tôt que les jeunes et ne bénéficient pas de cette dernière. Les résultats expérimentaux laissent envisager l'application du paradigme « canne mobile » à la locomotion
This work was dedicated to the study of the effects of haptic supplementation on postural stability of young and old adults during standing and sitting tasks. The question of whether haptic information provided by a mobile support improves stability similar to a fixed support has been rarely studied. The present work aimed to contribute to a better understanding of the underlying mechanisms of the potential stabilizing effect of haptic information provided by a cane-like support. The analysis focused on the center of pressure (COP). The results of the first two studies confirmed our general hypothesis about the effect of haptic supplementation independent of age and the mobility of the support. If sufficient resistance is provided by the support against body sway participants improved their postural stability. In the third study, we also manipulated visual inputs and the results suggested that a lack of vision can be compensated due to supplementation. In the fourth study, we also analyzed the inter-segmental coordination. The results suggested a better postural control due to supplementation whereas it does not affect the inter-segmental coordination. The fifth study aimed to determine whether haptic supplementation improves the system's robustness to sudden perturbations. The results suggested that only young participants reduce the time to the first COP correction due to supplementation while elderly correct the COP earlier than young adults, even without additional haptic information, and therefore do not benefit from haptic supplementation. Overall, the experimental results open the way for the application of the “mobile-stick” experimental paradigm to locomotion

Quel rôle joue la gravité dans les représentations internes de l'action ? Au-delà des contraintes d'équilibre, le vecteur gravitaire influence-t-il l'action de façon globale, jusqu'à la perception des mouvements de nos semblables ? Ces questions ont été celles qui ont guidé mes travaux de thèse. L'originalité de notre approche a été de placer l'exécution et la perception de l'action dans un « continuum fonctionnel » s'articulant autour des représentations internes de l'action. Pour ce faire, l'outil de choix qui est commun aux trois expériences de cette thèse est la microgravité (0G). Les expériences de cette thèse ont montré que les représentations internes de l'action se nourrissaient des informations graviceptives pour se construire et s'adapter constamment. Cependant, dans certaines conditions telle que la 0G à court terme, apparaît un ordre de priorité. En effet, le SNC est capable de mettre en place des solutions immédiates et efficaces pour l'exécution, comme en témoigne la repondération sensorielle rapide qui s'opère en 0G dans une tâche d'orientation posturale. Cependant, un temps de latence est observé dans la recalibration des modèles internes sur la base des afférences sensorielles fortement perturbées. C'est ce que nous avons montré grâce à un protocole d'imagerie motrice, mettant en évidence une perte de l'isochronie entre les mouvements exécutés et imaginés en 0G. Enfin, nous avons mis en évidence, chez des sujets sans expérience aucune de microgravité, que la perception du mouvement humain est efficace même lorsque ce dernier est exécuté en apesanteur, bien que des réseaux cérébraux différents soient mis en jeux
What is the role of gravity in the internal representations of action? Beyond the constraints of balance, does the gravity vector influence the action globally, up to the perception of our peers' movement? These issues have guided my thesis work. The originality of our approach was to place the execution and the perception of action in a "functional continuum" built around the internal representations of the action. To do this, the tool of choice, that is common to all three experiments presented here, is microgravity (0G). The experiments of this thesis showed that the internal representations of action are fed with graviceptive information to build and adapt constantly. However, under certain conditions such as short-term 0G, an order of priority appears. Indeed, the CNS is able to implement immediate and effective solutions, as we demonstrate it with the fast sensorial reweighting observed during a postural orientation task. However, a lag is observed in the recalibration of internal models based on sensory inputs severely disrupted. This is what we have shown through a protocol of motor imagery, showing a loss of isochrony between executed and imagined movements under 0G. Finally, we have demonstrated in subjects without any experience of microgravity, that the perception of human movement is effective even when it is performed in weightlessness, although different cerebral networks are involved

L'intento perseguito nel redigere questa tesi è quello di illustrare la teoria alla base delle onde gravitazionali per giungere ad intuire i metodi che ne consentono la rilevazione. Queste sono una conseguenza della Teoria della Relatività Generale di cui si riporta una semplice introduzione nel primo capitolo, sottolineando l'importanza del formalismo geometrico e tensoriale. Le equazioni di Einstein descrivono il campo gravitazionale come curvatura dello spaziotempo, questa è rappresentata dal tensore di Riemann che determina in particolare l'accelerazione relativa di due geodetiche. Si studia poi l'approssimazione di campo debole, necessaria per linearizzare le equazioni di Einstein e per mostrare che la perturbazione metrica soddisfa un'equazione d'onda. Il capitolo terzo si conclude quindi con un'analogia tra le onde gravitazionali e quelle elettromagnetiche. Nel quarto capitolo si analizzano le soluzioni sotto forma di onde piane: qui emergono caratteristiche peculiari riguardanti la perturbazione gravitazionale che, con il giusto gauge, permette di dedurre che solo due sono le polarizzazioni fisicamente rilevanti e che sono trasversali rispetto alla direzione dell'onda. Infine si evince che è necessario un sistema di particelle per la rilevazione di un'onda perchè la grandezza da osservare è la separazione tra due geodetiche e come questa varia al passaggio dell'onda. In questo modo viene mostrata la causa degli effetti mareali e si confermano le caratteristiche della radiazione gravitazionale anticipate in precedenza, come la polarizzazione e la natura quadripolare. Alcune considerazioni matematiche finali elucideranno come le proprietà delle onde suggeriscono con naturalezza l'esistenza di una radiazione di gravità. Infine si accennerà alle idee chiave che hanno suggerito la costruzione di rilevatori di onde e come questi debbano funzionare. La trattazione termina con uno sguardo alle recenti scoperte e alle aspettative future.

碩士
國立屏東科技大學
動物科學與畜產系所
104
In meat processing industry, the artificial antioxidants were usually used for keeping the quality of the meat products. However, these artificial additives are not much acceptable for the consumer recently. The chia seed contain high amount of ω-3 fatty acids, dietary fibers and phenolic compounds which could become a natural source of antioxidant to enhance the quality of meat products. The aim of this study was to evaluate the effect of chia seed on the quality, digestibility, antioxidant and sensory property of chicken cutlet during 18-week frozen storage. This study was divided into the three stages; the first stage was to the evaluate effect of different forms of chia seed (whole grain, seed powder) on the sensory property of chicken cutlet; the second stage was to evaluate the effect of different levels of chia seed (0.0-6.0%) and water (30-40%) on the physiochemical property of the chicken cutlet; the third stage was to evaluated the effect of chia seed on the digestibility and unsaturated fatty acid content of the cutlet. The result of sensory evaluation in the first experiment showed that the chicken cutlet made with whole grain chia seed had higher sensory score than with power seed one, The whole grain chia seed was better suited for the cutlet. With different level of whole grain chia seed in the cutlet, the higher seed content cutlet showed lower sensory score, especially at color, flavor, hardness and chewiness, so the cutlet with 0%, 2%, 4% and 6% seed content would be better treatments for experiment 2. In the second experiment, the ash content of cutlet increased with the chia seed content, but the seed had no effect on the water, protein and fat content of the cutlet. In 30% water treatment for cutlet showed higher protein and fat content than the cutlet with 35% and 40% water content. During 18-week and -20°C storage, the total bacterial count of the cutlet has no change, but the 6% chia seed group showed higher bacterial count than others. In sensory evaluation, the cutlet made with 2% chia seed and 35% water showed the highest acceptability score, and 6% seed cutlet showed the lowest score at color, aroma and acceptability. As theses result in experiment 2, the 0%, 2%, 4% chia seed with 35% water content of the cutlet would be adopted for the total phenolic content (TP), DPPH scavenging capacity (DPPH) and 2-thiobabituric acid reactant substance (TBARS) as the antioxidant evaluation. The result showed the TP and DPPH of the cutlet increase with the chia seed content, but time had no effect on both results. On contrary, the TBARS rose with the storage time but the chia seed content. In experiment 3, the digestibility of the cutlet was effect by the storage time. At ninth week storage, the total digestibility of the cutlet increase from 60% at the beginning to 66%; The linoleic and linolenic acid content of the cutlet increased with chia seed content, but time had no effect on these fatty acid content. As these result, the chia seed can promote the antioxidant and prevent the oxidative cleavage of unsaturated fatty acid of the chicken cutlet to develop the high functional processing meat product.

L’asymétrie de mise en charge (MEC) lors du passage assis à debout (PAD) chez les personnes hémiparétiques est une observation clinique connue mais peu expliquée. Ce projet visait donc le développement de connaissances sur les facteurs explicatifs de l’asymétrie de MEC chez cette clientèle en s’intéressant plus spécifiquement au lien entre la distribution des efforts aux genoux lors du PAD et l’asymétrie de MEC observée ainsi qu’à la perception de ces deux éléments lors de cette tâche. Ainsi, les objectifs généraux étaient de : 1) déterminer si l’exécution spontanée asymétrique du PAD des sujets hémiparétiques est expliquée par une distribution des efforts symétriques aux genoux en quantifiant ces efforts par le Taux d’utilisation musculaire électromyographique (TUMEMG) et, 2) déterminer si les individus hémiparétiques sont conscients des stratégies motrices qu’ils utilisent en évaluant leurs perceptions de MEC et d’efforts aux genoux durant le PAD. La première étude a évalué la capacité des personnes hémiparétiques à percevoir leur distribution de MEC aux membres inférieurs lors du PAD. Par rapport aux participants sains, leur distribution de MEC fut davantage asymétrique et leurs erreurs de perception plus élevées. La deuxième étude a quantifié la distribution des efforts aux genoux chez les sujets sains et hémiparétiques lors du PAD spontané. Les deux groupes ont montré une association entre leur distribution de MEC et leur distribution d’effort. Toutefois, la relation était plus faible chez les patients. Le classement des participants hémiparétiques en sous-groupes selon leur degré d’asymétrie de force maximale des extenseurs des genoux (faible, modéré, sévère) a révélé une similarité des efforts aux genoux parétique et non parétique chez le groupe ayant une atteinte sévère. La troisième étude a déterminé si la perception de la distribution des efforts aux genoux des sujets hémiparétiques était reliée à leur distribution réelle d’effort mesurée lors de PAD exécutés dans différentes positions de pieds. En plus d’être incapables de percevoir les changements de distribution d’effort induits par les différentes positions de pieds, leurs erreurs de perception d’effort furent plus élevées que celles de MEC. Par le biais du test fonctionnel assis-debout de cinq répétitions, la dernière étude a déterminé l’influence du nombre de répétitions du PAD sur les distributions de MEC et d’efforts aux genoux chez les sujets sains et hémiparétiques. Contrairement aux contrôles, les distributions des sujets hémiparétiques furent plus asymétriques à la première répétition du test fonctionnel que lors de l’exécution spontanée unique du PAD. En somme, les résultats de cette thèse ont démontré que la distribution des efforts aux genoux doit être considérée parmi les facteurs explicatifs de l’asymétrie de MEC des individus hémiparétiques lors du PAD et qu’il y a un besoin de mieux documenter la perception des personnes hémiparétiques lorsqu’elles exécutent des tâches fonctionnelles.
Weight-bearing (WB) asymmetry during sit-to-stand (STS) in hemiparetic individuals is frequently observed in clinical practice but it has never been well explained. The aim of this project, therefore, was to develop our knowledge of the factors accounting for the WB asymmetry in this population by focusing more specifically on the relationship between the knee effort distribution during the STS task and the WB asymmetry observed as well as on the perception of these two elements during this task. Thus, the general objectives were to: 1) determine whether the spontaneous asymmetrical execution of the STS task in hemiparetic subjects can be explained by a symmetrical distribution of the efforts at the knees by quantifying these efforts using the Electromyographic Muscular Utilization Ratio (EMUR) and, 2) determine whether these hemiparetic individuals are aware of their motor strategies by evaluating their perception of both knee effort and WB distributions during the STS task. The first study evaluated the capacity of hemiparetic persons to perceive their WB distribution at their lower limbs during the STS task. Compared to the healthy participants, their WB distribution was more asymmetrical and they showed greater errors in perception. The second study quantified the distribution of efforts at the knees among healthy and hemiparetic subjects during a spontaneous STS task. Both groups showed an association between their WB distribution and their distribution of efforts but the relationship was not as strong in the hemiparetic group. Dividing the hemiparetic participants into subgroups, according to their knee extensors’ strength asymmetries (mild, moderate, severe), revealed symmetrical knee efforts between sides for the severe group. The third study determined whether hemiparetic individuals’ perception of their knee effort distribution was related to their real distribution of efforts measured during STS tasks performed in various foot positions. Not only were they unable to perceive the changes in the distribution of effort induced by the different foot positions but their errors in perception of effort were greater than in WB. With the use of the five-repetition sit-to-stand test, the last study determined the influence of the number of repetitions of the STS on the distributions of WB and effort at the knees among healthy and hemiparetic subjects. Unlike the controls, the distributions of the hemiparetic subjects were more asymmetrical at the first repetition of the functional test than in the single spontaneous execution of the STS. To summarize, the results of this thesis showed that the distribution of efforts at the knees should be considered among other factors explaining the WB asymmetry of hemiparetic individuals during STS and that there is a need to better document the perception of hemiparetic persons when they execute functional tasks.