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This study concerns students' ideas about the existence or otherwise of forces in several dynamical situations involving moving objects and objects at rest. It aims to contribute to a better understanding of students' ideas about dynamics. It differs from previous research (a) in covering a wider-range among students and larger variation in taught Physics background. (b) in attempting to tap less verbal forms of evidence and (c) in attempting to avoid 'scientifism' in terms of the way to approach students and in terms of interpreting results. The empirical part of the study involved 338 students from seven different groups. Data was collected from the above sample. using a questionnaire to which responses were simply graphic indications of the directions of expected forces. and. if possible. the giving of names to these forces. in eight situations presented diagrammatically. In addition. data was collected from a sub-sample. by means of computer games using a screen 'object' obeying Newtonian Mechanics. in a frictional and a non-frictional 'environment'. under the control of the subject. Difficulties in interpreting the last kind of data led to the main study being focussed on the results of the questionnaire. Some results from the computer games are however presented. They are mainly concerned with students' performance when playing in a frictional versus non-frictional 'environment'. Results suggest a better students' performance when playing in a frictional 'environment'. Results obtained with the questionnaire concern: (a) differences between situations in patterns of expected directions. among students of the same group and between groups. Generally the results suggest the existence of common patterns among the students of the same group and systematic differences between patterns of groups with an increase in exposure to physics teaching. namely the attribution of new force directions [e.g. vertical and downwards. opposite to motion). despite the persistence of primitive ideas (e.g. a force along the motion); (b) names given to the different kinds of forces in various directions. Results include a difficulty found in naming forces which existed before teaching. They also give information about how scientific terms are assimilated. Interpretations of the results. mainly taken from a theory of Common Sense Reasoning about motions proposed by Ogborn (1985). seem to give them a reasonable explanation. Although requiring further investigation. this gives some support to claim that students' intuitive ideas about dynamics should be regarded [i] as deriving from a rather general and coherent set of ideas, [ii] as less formalized in terms of the scientific world view and [iii] as having their origin mainly in actions on the world.

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La caractérisation et la simulation des écoulements internes au sein des moteurs àpropergol solide, en considérant des mécanismes physiques fortement couplés, constituentl’objectif principal de ce mémoire de thèse. Dans cette optique, la conjonction entrefluide/régression de surface/couplage fluide structure a imposé de déployer une stratégiepropre lors du développement de la modélisation numérique. En effet, le modèle intègre untraitement de frontière immergée couplé avec un suivi de frontière mobile afin de pouvoirrendre compte de la formidable variation géométrique interne subie au cours d’un tir. Côtéfluide, un maillage automatique est nécessaire et la gestion de ce dernier s’appuie sur undéveloppement récursif avec structure hiérarchisée de type 2n tree. Une attention particulièrea été portée sur le solveur lui-même avec une approche explicite en temps et un schémanumérique basé sur l’approche de Roe avec limiteur de flux au second ordre. Des cas testsont été réalisés afin de valider le solveur et les différentes conditions aux limites introduites,notamment des conditions spécifiques développées pour les besoins de simulation. Lespremiers résultats soulignent tout l’intérêt du modèle proposé et sauf erreur de notre part,pour la première fois, l’analyse des sources tourbillonnaires responsables des instabilités ausein de ces moteurs a été étudiée en intégrant les effets du changement continu de géométrie.Finalement, la faisabilité d’une interaction forte entre solveur fluide et solveur solide a étéréalisée sur un modèle simplifié d’un moteur segmenté.L’ensemble des développements permet un accès aux mécanismes couplés complexeset aux fortes interactions au sein des moteurs à propergol solide et offre de nouvellesperspectives dans la caractérisation des mécanismes fortement couplés. / Characterization and simulation of internaI flow within the solid rocket motors, considering the physicalmechanisms strongly coupled, are the main focus of this thesis objective. In this context, the conjunctionbetween fluid/regression surface/fluid coupling structure imposed deploy c1ean during the development ofnumerical modeling strategy. Indeed, the model incorporates treatment coupled with an immersed boundarytracking moving boundary in order to realize the tremendous internai geometric variation experienced during ashot. Fluid side, an automatic mesh is required and the management of the latter is based on a recursivehierarchical structure development with type 2" tree. Particular attention was paid to the solver itself with anexplicit approach to time and a numerical scheme based on the approach of Roe with flow limiter in the secondorder. Tests cases were conducted to validate the sol ver and different boundary conditions introduced, inc1udingspecific conditions developed for the purpose of simulation. The first results emphasize the interest of theproposed and unless our error model, for the first time, the analysis of the sources responsible vortex instabilitiesin these engines has been studied by incorporating the effects of continuous change in geometry. Finally, thefeasibility of a strong interaction between fluid and solid solver was conducted on a simplified model of a multiengine.AlI the developments allows access to complex mechanisms coupled and strong interactions in solidrocket motors and off ers new insights into the characterization of strongly coupled mechanisms.

A thesis submitted to the Faculty of Arts in fulfilment of the requirements for the Degree of Masters in Communication Science in the Department of Communication Science at the University of Zululand, South Africa, 2014. / Manufacturers, wholesalers and retailers of Fast Moving Consumer Goods (FMCG) have a social responsibility towards their consumer’s environment. Fast Moving Consumer Goods are consumed on a daily basis and their by-products are often discarded incorrectly, impacting negatively on the environment. However, many companies are beginning to take steps towards ensuring that their products are manufactured according to environmentally friendly conditions. The responsibility should not just be placed on labels, but consumers should be properly educated and guided on how to dispose of a product’s packaging such as bottles, cans and plastic bags. Producers, as well as retailers, of FMCG have an ethical responsibility towards their consumers. It has become fashionable and politically correct for FMCG companies all over the world to publicise themselves as “green companies.” However, the materials used in the packaging of these products are most often found thrown in streets and other open areas in the community. This research investigates the impact that FMCG have on the community’s green space and how companies and retailers can effectively communicate their green consumerism initiatives and demonstrate their CSR for both the environment and their consumers. This study revealed that 53.99% of the respondents do not recycle the unused packaging of goods. The primary reason was that recycling is inconvenient. The other conspicuous reason was lack of knowledge of recycling. Apart from that, they also mention that they do not have recycling bins in the community; they have not enough space in their yard and for the fact that they are not getting any incentives. This study focuses on how companies can assist in saving our planet by embracing the concept of green consumerism holistically. Further, the study exposes challenges faced by companies and social organisations with regard to green consumerism. It also tackles existing initiatives of entrenching green consumerism and the study goes on to offer suggestions and recommendations to effectively embrace green consumerism in a global society.

This research studies lateral transshipment of critical medical items that have low demands. Due to the high prices of medical items and their limited shelf lives, the expirations contribute significantly to the current prohibitively high cost of the healthcare system. Lateral transshipment between hospitals in a medical system provides opportunities to reduce the expiration costs. This paper studies the decision rule for lateral transshipment in a two-hospital system and extends the rule for the multiple-hospital cases. The decision rule takes the myopic best action by assuming no transshipments will be performed in the future. Numerical experiments demonstrate significant cost savings and the decision rule has a small gap from the upper bound of the total saving. The savings are more considerable when the difference of demand rates at different locations is large and the life time of the medical item is not too long or too short.

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