Les activités humaines produisent des eaux usées dont le traitement génère des boues d’épuration urbaines. Ces boues font l’objet de recherches visant à les transformer en produits à forte valeur ajoutée. Elles pourraient ainsi passer d’un statut de déchet fatal au statut de coproduit attendu à l’issue de l’épuration des eaux. Ce changement de paradigme a des conséquences sur l’évaluation environnementale par Analyse du Cycle de Vie (ACV) des produits « boue-sourcés ». La boue devient un coproduit attendu de la station de traitement des eaux et la charge environnementale liée à leur production doit pouvoir être répartie entre coproduits au moyen d’un facteur d’allocation. Cette thèse propose une construction mathématique de ce facteur d’allocation en combinant des paramètres « procédés » et « produits », intégrant de facto les relations causales entre conduite du procédé et obtention des produits, reflétant la réalité technologique du procédé. La résultante se présente sous la forme d’une matrice dont chaque élément associe, pour chaque donnée d’inventaire, un facteur d’allocation à chacun des coproduits générés. Appliquée à la production de fertilisants phosphatés boue-sourcés, l’ACV réalisée a permis de mettre en lumière la contribution majeure de l’étape de production par rapport aux étapes de traitement et valorisation de la boue. Cette méthodologie de construction d’un facteur d’allocation permet toutefois d’attribuer une charge environnementale à chacun des coproduits d’un système de production indivisible et peut également être utilisée de manière pertinente lors de l’évaluation environnementale des procédés de séparation de nature thermique, chimique ou physique. / Human activities produce wastewater that generates sludge, a waste recycled on agricultural soils or for energy recovery. Extensive research is currently undergone on sludge to develop processes that can convert it into products with high-added value. In this context, sludge could move from a fatal waste status to the status of an expected co-product of wastewater treatment. This paradigm shift has implications for the assessment of environmental impacts of "sludge-based" materials with Life Cycle Assessment. Indeed, sludge becomes an expected co-product from the wastewater treatment plant and the environmental burden of their production must be distributed among co-products by means of an allocation factor. This thesis aims at defining a mathematical construction of this allocation factor by combining process- and product-related parameters, integrating de facto the causal relationships between process operations and products generation and the technological reality of the process. The result is a matrix of which each element associates, for each inventory data, an allocation factor to each of the generated co-products. Applied to the production of sludge-based phosphate fertilizers, LCA highlights the major contribution of the production stage compared to the stages of treatment and recovery of the sludge. Nevertheless, the method developed within this thesis to allocate an environmental load to each co-products of an indivisible production system paves the way for a more coherent environmental assessment of waste-based products. This methodology can also be used effectively in the environmental assessment of thermal, chemical or physical separation processes.

<p>The purpose of this study is to investigate teachers 'and students' understanding of why students finish school with incomplete scores and which resources they consider necessary for students to accomplish the goals that are set for the students. Owing to the reuse of pupils and teachers' experiences, this study will highlight significant qualitative aspects of work with students who finish school with incomplete high school grades. Hopefully, will this study be a support and information base in secondary school.</p><p>The material forming the basis for the report's theoretical assumptions and the basic assumption is based on Lev Vygotsky sociocultural perspective on learning that Olga Dysthe discuss and develop further in his book, <em>Dialog, samspel och lärande</em>.  The present work is based on qualitative research method. I selected this research method because I am interested in getting an understanding of the importance and significance of this research The study applied a qualitative interview format.</p><p>As a result of the investigation as it has appeared that students difficulties to achieve the goals,depends on several factors, mostly on the student's socio-economic and psychosocial situation they live in. The life situation of the students determines the learning and knowledge process and how they reach their goals. The study concludes that a better synergy between the various stages need to be improved, the necessary resources, teachers need to understand the course objectives and then enlighten them to the students. As a final point, more explicit syllabus is needed owing to the easiness of being interpretable. Having more straightforward syllabus, unfair judgment will be prevented.</p><p> </p>

The purpose of this study is to investigate teachers 'and students' understanding of why students finish school with incomplete scores and which resources they consider necessary for students to accomplish the goals that are set for the students. Owing to the reuse of pupils and teachers' experiences, this study will highlight significant qualitative aspects of work with students who finish school with incomplete high school grades. Hopefully, will this study be a support and information base in secondary school. The material forming the basis for the report's theoretical assumptions and the basic assumption is based on Lev Vygotsky sociocultural perspective on learning that Olga Dysthe discuss and develop further in his book, Dialog, samspel och lärande.  The present work is based on qualitative research method. I selected this research method because I am interested in getting an understanding of the importance and significance of this research The study applied a qualitative interview format. As a result of the investigation as it has appeared that students difficulties to achieve the goals,depends on several factors, mostly on the student's socio-economic and psychosocial situation they live in. The life situation of the students determines the learning and knowledge process and how they reach their goals. The study concludes that a better synergy between the various stages need to be improved, the necessary resources, teachers need to understand the course objectives and then enlighten them to the students. As a final point, more explicit syllabus is needed owing to the easiness of being interpretable. Having more straightforward syllabus, unfair judgment will be prevented.

The South African context, in particular, is characterized by a definite need for the facilitation of the development of the youth in a more positive trajectory. Family structures are not always robust enough to support the positive development of the youth, owing to the demands made on single–parent families, amongst other reasons. Community structures may also be less supportive of the development of the youth, because of the impact of the changes associated with the transitional phase of the country during the past sixteen years (Meehan, Peirson & Fridjhon, 2007). Furthermore, young people under the age of 15 years comprise almost a third of the total South African population (Statistics South Africa, 2009), and in the future, they will have to be prepared for an adulthood faced with previously unknown challenges (United Nations Population Fund). The importance of the development of the youth, in order to enable them to contribute to their country in future, is acknowledged by the South African Governement (National Youth Commission website). This study was conducted within the parameters of the newly developing positive youth development (PYD) paradigm. The empirical level of this paradigm is well represented in the literature, indicating that the content areas, or the “what” of PYD, have been well elucidated. However, there is a lack of theory, especially with regard to models describing developmental change (Larson et al., 2004), and evaluation of interventions aiming at the facilitation of PYD. In order to contribute to the answering of the questions regarding the “how” of development, this study had the following main aims: a) the compilation of a theoretical model, describing developmental change in the youth; b) the operationalization of this model for intervention purposes; and c) the evaluation of a programme and the model on which it is based. The study is reported on in an article format, and comprises a total of three articles. The first article focuses on the process of the compilation of a theoretical model by means of: a) the construction of a comprehensive meta–theoretical matrix, b) the integration of theory that features in the PYD literature, and c) the expansion of the latter with theory from other compatible sub–disciplines in psychology. The resultant Positive Youth Development Intervention (PYDI) model provides a process–related description of developmental change ? and is one of the first models to do so. The second article describes the operationalization of the PYDI model, by means of an indication of the relevant constructs, phenomena and processes to be facilitated. Although recent research points to a relation between PYD and self–regulation, there has been no model, describing the role of self–regulation in the facilitation of the positive development of the youth. This study adapted a model from an educational context (Heckhausen & Gollwitzer, 1987 (as cited in Boekaerts & Niemivirta, 2005)), in order to describe the regular self–regulatory processes constituting the bi–directional interactions between the youth and their primary life contexts, as proposed by developmental systems theory (Lerner, 1998), the meta–theory to PYD (King et al., 2005). A further specifc contribution is that the presentation aspects of the programme material, aimed at facilitating the integration thereof, are addressed on a theoretical level. The third article describes the evaluation of the PYDI model and programme, with young adolescents in a school in a rural area as participants. A mixed–methods study, which has been shown to render much richer information than a quantitative study alone, was applied. Although the quantitative data did not prove the success of the programme, the qualitative data suggested that some aspects of self–regulation had indeed been facilitated successfully. A second follow–up assessment, conducted seventeen months later, indicated that certain skills had only become internalized by that time, suggesting that the implementation and evaluation of such a programme should be expanded over an extended time–frame. This study has contributed to the level of theory of PYD, by indicating, a) the lacunae, and b) that theory in compatible sub–disciplinary paradigms could be used in order to devise workable models for PYD. Furthermore, the process–related nature of the PYDI model and programme, owing to its adaptability to different needs, may be adapted and extended to be applicable to the needs of the diverse South African population. Recommendations regarding future application and research, especially within the South African context, have also been put forward in the study. / Thesis (Ph.D. (Psychology))--North-West University, Potchefstroom Campus, 2011.

The South African context, in particular, is characterized by a definite need for the facilitation of the development of the youth in a more positive trajectory. Family structures are not always robust enough to support the positive development of the youth, owing to the demands made on single–parent families, amongst other reasons. Community structures may also be less supportive of the development of the youth, because of the impact of the changes associated with the transitional phase of the country during the past sixteen years (Meehan, Peirson & Fridjhon, 2007). Furthermore, young people under the age of 15 years comprise almost a third of the total South African population (Statistics South Africa, 2009), and in the future, they will have to be prepared for an adulthood faced with previously unknown challenges (United Nations Population Fund). The importance of the development of the youth, in order to enable them to contribute to their country in future, is acknowledged by the South African Governement (National Youth Commission website). This study was conducted within the parameters of the newly developing positive youth development (PYD) paradigm. The empirical level of this paradigm is well represented in the literature, indicating that the content areas, or the “what” of PYD, have been well elucidated. However, there is a lack of theory, especially with regard to models describing developmental change (Larson et al., 2004), and evaluation of interventions aiming at the facilitation of PYD. In order to contribute to the answering of the questions regarding the “how” of development, this study had the following main aims: a) the compilation of a theoretical model, describing developmental change in the youth; b) the operationalization of this model for intervention purposes; and c) the evaluation of a programme and the model on which it is based. The study is reported on in an article format, and comprises a total of three articles. The first article focuses on the process of the compilation of a theoretical model by means of: a) the construction of a comprehensive meta–theoretical matrix, b) the integration of theory that features in the PYD literature, and c) the expansion of the latter with theory from other compatible sub–disciplines in psychology. The resultant Positive Youth Development Intervention (PYDI) model provides a process–related description of developmental change ? and is one of the first models to do so. The second article describes the operationalization of the PYDI model, by means of an indication of the relevant constructs, phenomena and processes to be facilitated. Although recent research points to a relation between PYD and self–regulation, there has been no model, describing the role of self–regulation in the facilitation of the positive development of the youth. This study adapted a model from an educational context (Heckhausen & Gollwitzer, 1987 (as cited in Boekaerts & Niemivirta, 2005)), in order to describe the regular self–regulatory processes constituting the bi–directional interactions between the youth and their primary life contexts, as proposed by developmental systems theory (Lerner, 1998), the meta–theory to PYD (King et al., 2005). A further specifc contribution is that the presentation aspects of the programme material, aimed at facilitating the integration thereof, are addressed on a theoretical level. The third article describes the evaluation of the PYDI model and programme, with young adolescents in a school in a rural area as participants. A mixed–methods study, which has been shown to render much richer information than a quantitative study alone, was applied. Although the quantitative data did not prove the success of the programme, the qualitative data suggested that some aspects of self–regulation had indeed been facilitated successfully. A second follow–up assessment, conducted seventeen months later, indicated that certain skills had only become internalized by that time, suggesting that the implementation and evaluation of such a programme should be expanded over an extended time–frame. This study has contributed to the level of theory of PYD, by indicating, a) the lacunae, and b) that theory in compatible sub–disciplinary paradigms could be used in order to devise workable models for PYD. Furthermore, the process–related nature of the PYDI model and programme, owing to its adaptability to different needs, may be adapted and extended to be applicable to the needs of the diverse South African population. Recommendations regarding future application and research, especially within the South African context, have also been put forward in the study. / Thesis (Ph.D. (Psychology))--North-West University, Potchefstroom Campus, 2011.