Teses / dissertações sobre o tema "Basel Convention"

Thesis advisor: Brian J. Gareau
For my dissertation research, I am focused on the sociopolitical relations of electronics disposal, a less-considered but increasingly important stage in the life cycle of electronics. Although much has already been written on the global trade in hazardous wastes, the Basel Convention that regulates this trade, and the environmental injustice of the global waste trade--with wealthy countries dumping the "negative externalities" of their consumption on vulnerable communities in the global South--the reality today appears to be more complex. Regulators in the Basel Convention and the UN Environment Program, as well as civil society actors in industry and NGOs, have an increased interest in promoting the development of markets and infrastructure in high tech e-waste recycling. Historically, e-wastes have been both talked about, and treated as, a toxic and unwanted byproduct of the digital age. However, today key actors in the regulatory, industrial and civil society spheres are now discussing e-wastes as critical "resources" for economic and technological development. I hypothesize that uncovering the economic, technological and geopolitical drivers of this shift will reveal that the global trade in e-wastes can no longer be described as a clear-cut North/South, "perpetrator-victim," scenario, rather, it must be seen as a dynamic process where environmental inequalities are mitigated and reconstituted in new forms and at various sites. I identify two dominant paradigms that scholars, activists, policy makers and industry actors employ in evaluating the global trade in electronic wastes. I label these two paradigms the "environmental justice evaluation" and the "resource capture evaluation." By engaging concepts from global political economy and environmental sociology (particularly, O'Connor 1979; Harvey 2003; Pellow 2003) and applying them to my case, my dissertation attempts to bring a nuanced perspective to the e-waste debate. My initial findings suggest that both of these frameworks do not account for the key economic processes that are driving the e-waste trade. A better understanding of these processes will better illuminate the pathway to finding meaningful solutions to the persistent, presently illegal global trade in discarded electronics. My data consists of a comprehensive examination of meeting archives from the Basel Convention (where the experts and political decision makers on this issue implement policies that affect the global e-waste trade) spanning from 1992 to the present, as well as reviews of the proceedings of other relevant actors in e-waste policy (for example, annual meetings of the global organization StEP, and publications and pamphlets from trade organizations in the US and abroad and publications from the US government). In addition, I conducted semi-structured interviews with 25 key actors in the national regulatory, global regulatory, industry and NGO spheres in order to understand how the key decision makers in the e-waste trade understand the drivers and implications of the shift "from waste to resources." Finally, I draw on ethnographic observations conducted at a pivotal Basel Convention meeting in 2011, where a decision was made that has the potential to fundamentally reshape the Basel Convention and enable increased global trade in discarded electronics through the development of formalized recycling centers in less-developed countries
Thesis (PhD) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Sociology

The quest for sustainable development has always involved the complex task of reconciling the need for socio-economic development with public health and environmental protection. This challenge has often emerged in the trade and environment debate but has most recently been evident in international trade in used electrical and electronic equipment (UEEE). While international trade in UEEE provides means for socio-economic development in the developing world, it also serves as a conduit for transboundary dumping of e-waste in the developing world giving rise to serious health and environmental concerns. This research investigates the socio-economic as well as health and environmental impacts of international trade in UEEE in two developing countries – Nigeria and Ghana. The research identifies a major loophole in the existing international legal framework as the primary factor responsible for e-waste dumping in the developing world. This loophole relates to the absence of a legal framework for differentiating between functional UEEE and junk e-waste. This has resulted in both functional UEEE and junk e-waste being concurrently shipped to the developing world as “used electrical and electronic equipment”. The research proposes two policy frameworks for addressing this problem. On the part of developing countries, the research proposes a trade policy framework crafted in line with WTO rules. This framework will entail the development of an international certification system which will serve to differentiate functional used electronics from junk e-waste. While the former may be eligible for import, the research proposes an import ban on the latter. On the part of developed countries, the research proposes the development of a policy framework which regulates the toxic and hazardous substances that go into the production of electrical and electronic equipment as well as enhance their reusability and recyclability at end-of-life. The framework should take into consideration the entire life cycle of the products from the design stage to end-of-life. The research argues that the implementation of this design framework will go a long way in reducing the health and environmental impacts of such equipment when subsequently shipped to the developing world at end-of-life.

A Convenção de Basiléia sobre o Controle de Movimentos Transfronteiriços de Resíduos Perigosos e seu Depósito trata-se de um acordo que define mecanismos de organização dos movimentos transfronteiriços de resíduos sólidos e líquidos perigosos e sua disposição final. Os resíduos perigosos são materiais descartados que podem colocar em risco a segurança da vida.A Convenção para atingir seu propósito de existência permite a concessão prévia e explícita de importação e exportação dos resíduos autorizados entre os países que dela participam, de modo a evitar o tráfico ilícito. O Brasil através do Decreto número 875 de 1993 confirmou sua permanência como integrante da convenção, internalizando assim o documento no país. A partir de então, todo o comércio internacional de resíduos perigosos entre o Brasil e o exterior passou a ser regulamentado. Os resíduos industriais, considerados perigosos constituem, no Brasil, motivo de preocupação das autoridades e órgãos ambientais, seja devido às quantidades que vem sendo geradas, principalmente como resultado da elevada concentração industrial em algumas regiões do país, seja pela carência de instalações e locais adequados para o tratamento e destino final. Descrever e discutir as dimensões deste documento e ao mesmo tempo demonstrar sua repercussão na realidade brasileira será o propósito desta dissertação.
The Basel Convention about movement control cross border of danger residues and your deposit it cames agree that definite organization mechanisms from movements cross border of solids residues and dangerous liquids and your last arrangement. The dangerous residues are material discarded that can place in risk the security of life. The Convention to reach its intention of existence allow to the previous and explicit concession of importation and exportation of the authorized residues between the countries that of it participate, in order to prevent the illicit traffic. Brazil through the Decree 1993 number 875 confirmed its permanence as integrant of the convention, thus inserting so the document in country. From now on, all the international trade of dangerous residues between Brazil and the exterior passed to be regulated. The industrial residues, considered dangerous constitute, in Brazil, ambient reason of concern of the authorities and agencies, either had to the amounts that come being generated, mainly as resulted of the raised industrial concentration in some regions of the country, either for the lack of installations and places adjusted for the treatment and destination. To describe and to argue the dimensions of this document and at the same time to demonstrate its repercussion in the Brazilian reality will be the intention of this communication.

In the United Nations Convention on the Law of the Sea, the environmental protection of the marine environment was first addressed in a comprehensive manner on an international level. However, the Convention distinguishes between four different sorts of pollution depending on which source the pollution originates from. Still, one of these sources play a more crucial role in the protection of the marine environment than the other since that source is estimated to stand for 80 percent of all the marine pollution; namely marine pollution from land-based sources. As the throw-away culture has led to products being disposed of at a faster rate than ever before, in particular plastic products, the amount of land-based debris has also substantially increased over the last decades. This increased disposal rate of products in combination with poor waste treatment has consequently led to many kinds of wastes ending up in the ocean and causing severe harm, not only to the marine environment and its living species, but also to humans that eat the fish and use the many other ecosystem services of the Sea. In this thesis, some prominent international conventions on marine pollution from land-based sources are examined; namely the United Nations Convention on the Law of the Sea, the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, as well as the Stockholm Convention on Persistent Organic Pollutants. To achieve United Nations Sustainable Development Goal number 14.1 to significantly reduce marine pollution from land-based sources by 2025, this thesis claims that international laws addressing this sort of pollution need to be implemented. Moreover, this thesis rests on the belief that regional implementation is a crucial component in making states align with international law. However, while regional implementation has been ambitious in the European Union Law, many regions still lack enforceable frameworks that aim to reduce and prevent marine pollution from land-based sources.

Purpose/Aim: The purpose of this study is to understand the meaning of global responsibility and toxicwaste control. The Basel Convention is the UN's international regulations on the import, export andtransport of hazardous waste. According to the Basel Convention, the export of electronic waste todeveloping countries is fully legal if the recipient country has given approval in writing. Is there a linkbetween toxic colonialism, global responsibility, justice and human rights?Material/Method: A qualitative case study of what delegates from three African countries think abouttoxic colonialism and global responsibility.Main results: The essay gives an explanation of the concept of toxic colonialism in relation to the BaselConvention and the Ban Amendment, from three African UN delegates, furthermore an analysis of theimportance it can have on global responsibility, justice and views on human rights.The essay results show that the Ban Amendment of the Basel Convention is in line with Rawl'sdifference principle and the principle of freedom and would contribute to increased justice on electronicwaste coding if the amendment goes through and is used in symbiosis with human rights: UDHRArticle 25 and ICESCR Article 12.1-2.

A gestão dos resíduos gerados pela sociedade, que envolve seu tratamento, valorização, aproveitamento e/ou disposição final, é um tema global que demanda de governos, empresas e cidadãos soluções adequadas. O transporte transfronteiriço de resíduos considerado tráfico quando realizado ilegalmente tornou-se uma realidade a ser enfrentada, visto que transfere os impactos de resíduos perigosos de países geradores para países que frequentemente dispõem de meios escassos para lidar eficientemente com os mesmos, aumentando a probabilidade de problemas ambientais e de saúde pública. A Convenção da Basiléia, promulgada em 1989, estabeleceu regras e limites internacionais ao trânsito de resíduos perigosos. O Brasil, como signatário da Convenção, assumiu sua implementação através do Decreto nº 875 de 19 de julho 1993. À revelia das normativas existentes, ocorrem casos de tráfico de resíduos irregulares nas fronteiras e portos brasileiros. As importações irregulares identificadas são tratadas na forma da lei pelos órgãos competentes, gerando processos administrativos, autuações e notificações. Neste trabalho realizamos um levantamento descritivo dos casos de tráfico ilegal de resíduos identificados nas fronteiras e portos brasileiros e analisamos a eficiência e eficácia do governo brasileiro, através de seu órgão ambiental IBAMA/MMA, em coibir e impedir essa prática criminosa. Utilizamos para tanto os seguintes indicadores: a identificação das cargas irregulares pelos entes governamentais; a devolução das cargas aos países de origem; a autuação dos responsáveis pelo tráfico; a comunicação ao Secretariado da Convenção da Basiléia e as ações visando coibir esta prática. A análise dos dados levantados permitiu verificar a evolução dos procedimentos governamentais afetos à problemática e apontar lacunas existentes que limitam a eficácia e eficiência das ações empreendidas.
The management of the waste generated by society, involving its treatment, recovery, and/or final disposal, is a global issue that demands of governments, businesses and citizens appropriate solutions. Cross-border transport of dangerous waste considered illegal trafficking when performed irregularly became a reality to be faced, since it transfers the potential impacts of harmful wastes from generator countries to other regions which generally have limited means to handle efficiently with them, increasing the possibility of environmental and public health problems. The Basel Convention, enacted in 1989, established international rules and limits on hazardous waste transit. Brazil, as a signatory of the Convention, assumed its implementation through Decree nº 875 of July 19, 1993. Despite the existing regulations, there are cases of illegal waste trafficking identified at the Brazilian borders and seaports. Identified irregular imports are treated by the competent national bodies according to existing laws and rules, generating administrative proceedings, fines and notifications. In this work, we conduct a descriptive survey of cases of illegal waste trafficking identified at the borders and seaports and analyze the Brazilian government efficiency and effectiveness, through its environmental agency IBAMA/MMA, in curbing and preventing this criminal practice. For this intent, we analyzed the following indicators: the identification of irregular cargos by governmental agencies; proceedings adopted against those responsible for trafficking; the return of the irregular cargos to the countries of origin; communication to the Secretariat of the Basel Convention and the actions to curb this practice. The analysis of the collected data has shown progress in government procedures pertaining to the issue and point out gaps that limit the effectiveness and efficiency of the actions.

Sleep Convention Logic (SCL) is an emerging ultra-low power Quasi-Delay Insensitive (QDI) asynchronous design paradigm with enormous potential for industrial applications. Design validation is a critical concern before commercialization. Unlike other QDI paradigms, such as NULL Convention Logic (NCL) and Pre-Charge Half Buffers (PCHB), there exists no formal verification methods for SCL. In this thesis, a unified formal verification scheme for combinational as well as sequential SCL circuits is proposed based on equivalence checking, which verifies both safety and liveness. The method is demonstrated using several multipliers, MACs, and ISCAS benchmarks.

Artificial intelligence (Al) has received an explosion of interest during the last five years in various fields. There is no longer any question that expert systems and neural networks will be of central importance for developing the next generation of more intelligent geographic information systems. Such knowledge based geographic information systems will especially play a key role in spatial decision and policy analysis related to issues such as environmental monitoring and management, land use planning, motor vehicle navigation and distribution logistics. This paper sketches briefly the major characteristics of conventional geographic information systems, and then looks at some of the potentials of Al principles and techniques in a GIS environment where emphasis is laid on expert systems and artificial neural networks technologies and techniques. (author's abstract)
Series: Discussion Papers of the Institute for Economic Geography and GIScience

Human language is both a cognitive and a cultural phenomenon. Any evolutionary account of language, then, must address both biological and cultural evolution. In this thesis, I give a mainly cultural evolutionary answer to two main questions: firstly, how do working systems of learned communication arise in populations in the absence of external or internal guidance? Secondly, how do those communication systems take on the fundamental structural properties found in human languages, i.e. systematicity at both a meaningless and meaningful level? A large, multi-disciplinary literature exists for each question, full of apparently conflicting results and analyses. My aim in this thesis is to survey this work, so as to find any commonalities and bring this together in order to provide a minimal account of the cultural evolution of language. The first chapter of this thesis takes a number of well-established models of the emergence of signalling systems. These are taken from several different fields: evolutionary linguistics, evolutionary game theory, philosophy, artificial life, and cognitive science. By using a common framework to directly compare these models, I show that three underlying commonalities determine the ability of any population of agents to reliably develop optimal signalling. The three requirements are that i) agents can create and transfer referential information, ii) there is a systemic bias against ambiguity, and iii) some mechanism leading to information loss exists. Following this, I extend the model to determine the effects of including referential uncertainty. I show that, for the group of models to which this applies, this places certain extra restrictions on the three requirements stated above. In the next chapter, I use an information-theoretic framework to construct a novel analysis of signalling games in general, and rephrase the three requirements in more formal terms. I then show that we can use these 3 criteria as a diagnostic for determining whether any given signalling game will lead to optimal signalling, without the requirement for repeated simulations. In the final, much longer, chapter, I address the topic of duality of patterning. This involves a lengthy review of the literature on duality of patterning, combinatoriality, and compositionality. I then argue that both levels of systematicity can be seen as a functional adaptation which maintains communicative accuracy in the face of noisy processes at different levels of analysis. I support this with results from a new, minimally-specified model, which also clarifies and informs a number of long-fought debates within the field.

Despite the lack of a universal mathematical framework for the analysis of chaotic systems, development of analysis techniques has been swift due both to the research interest in chaos theory from many diverse subjects and to the vast computing resources now available. However, many potential applications remain in the realm of theory. This thesis provides a link between chaos theory and communication systems, with the aim of developing a modulation technique capable of implementation with current technology. Although potentially very simple, chaotic systems result in extremely complex behaviour, resulting in loss of predictability in the long term. Their sensitive dependence on initial conditions enables large-scale changes to be effected with small control perturbations, and their aperiodic behaviour results in broad power spectra. The potential for an electronically simple chaos-based transmitter architecture, employing direct modulation of the passband chaotic oscillator, provides the motivation for this research. Building on the fundamental properties and analysis tools of chaotic systems, an intuitive exploration of the chaos generation mechanisms of several single-scroll chaotic attractors is developed, leading to the creation of several novel chaotic attractors and a discussion of their applications. The concept of a flexible chaotic oscillator-based transmitter architecture which is compatible with standard synchronisation and demodulation techniques is considered, and the resulting noise performance of both simulation and hardware implementations found to be competitive with standard modulation techniques. Additionally, a powerful baseband simulation technique is proposed and implemented, leading to the suggestion of a digital baseband implementation of the transmitter and its potential applications. , Avenues of further work are identified, providing direction for improvements of the proposed system and other related branches worthy of further study.

Op amps are among the most-used components in electronic design. Their performance is important and is often measured in terms of gain, bandwidth, power consumption, and chip area. Although BJT amplifiers can achieve high gains and bandwidths, they tend to consume a lot of power. CMOS amplifiers utilizing the strong inversion region alone use less power than BJT amplifiers, but generally have lower gains and bandwidths. When CMOS SPICE models were improved to accurately simulate all regions of inversion, researchers began to test the performance of amplifiers operating in the weak and moderate inversion regions. Previous work had dealt with exploring the parameters of composite cascode stages, including inversion coefficients. This thesis extends the work to include conventional cascode stages and presents an efficient method for exploring design parameters. A high-gain (137.7 dB), low power (4.347 µW) operational amplifier based on the conventional cascode stage is presented.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Family farming has contributed to social development because through millions of small producers it has been a growing industry of entire relevance for the development of the country. Despite the high current production efficiency in agriculture it has been observed many environmental and social impacts, such as: soil erosion, contamination of surface and groundwater, loss of biodiversity, loss of traditional knowledge associated with economic dependence, reducing of job opportunities and income as well as rural exodus and social exclusion. For this reason, in the past few years it has been giving very strong focus on ecological benefits from cultivation of organic products. The general objective of this research is to comparatively analyze, based on indicators of economic, social and environmental indicators, two irrigated cultivation systems of organic and conventional production. The value of production and income of the farmer were respectively evaluated as variables associated to social and economic dimensions. The microbial activity of the soil was used as an environmental variable and the statistical analysis was performed using the program "ASSISTAT 7.5 BETA". The generation of direct jobs per area unit in the conventional tillage system corresponds to the reference values. Nevertheless, the organic system provides a generation of direct jobs that may reach three times the average capacity of employment generation per area unit of irrigated agriculture in the Brazilian semi-arid region, thus creating in a sustainable way, maintenance conditions for peasants. The organic system has a lower risk associated with the economic dimension compared to conventional tillage system. Current useful agricultural areas of the two production units allow them to remain in agricultural activity ensuring the social reproduction of farmers in a scenario with funding from the Pronaf. The results of the evaluated environmental variables demonstrate that production unit with organic farming has higher environmental sustainability, since the soil has good physical and chemical conditions that are more satisfactory to the development of microorganisms.
A agricultura familiar vem contribuindo para o desenvolvimento social, pois atravÃs de seus milhÃes de pequenos produtores à um setor em crescimento e de inteira relevÃncia para o desenvolvimento do paÃs. Apesar da elevada eficiÃncia produtiva atual na agricultura, tem se observado diversos impactos ambientais e sociais, tais como erosÃo dos solos, contaminaÃÃo das Ãguas superficiais e subterrÃneas, reduÃÃo da biodiversidade e perda de saberes tradicionais associados, dependÃncia econÃmica, reduÃÃo das oportunidades de trabalho e renda, Ãxodo rural e exclusÃo social. Por este motivo, nos Ãltimos tempos, tem se dado Ãnfase aos benefÃcios ecolÃgicos provenientes do cultivo de produtos orgÃnicos. A pesquisa tem como objetivo geral analisar comparativamente, a partir de indicadores de sustentabilidade econÃmica, social e ambiental, dois sistemas irrigados de produÃÃo, um orgÃnico o outro convencional. O valor da produÃÃo e da renda do agricultor foram avaliados como variÃveis associadas com dimensÃes sociais e econÃmicas, respectivamente. A anÃlise estatÃstica dos dados ambientais foi realizada atravÃs do programa âASSISTAT 7.5 BETAâ submetidos à anÃlise de variÃncia e as mÃdias comparadas pelo teste de Tukey. A geraÃÃo de empregos diretos por unidade de Ãrea no sistema de cultivo convencional corresponde aos valores de referÃncia. Jà o sistema de cultivo orgÃnico proporciona uma geraÃÃo de empregos diretos que chega a corresponder trÃs vezes à mÃdia da capacidade de geraÃÃo de emprego por unidade de Ãrea da agricultura irrigada na regiÃo do semiÃrido brasileiro, criando assim de forma sustentÃvel, condiÃÃes de permanÃncia do homem no campo. O sistema de cultivo orgÃnico apresenta um menor risco associado à dimensÃo econÃmica comparativamente ao sistema de cultivo convencional. As superfÃcies agrÃcolas Ãteis atuais das duas unidades de produÃÃo permitem que as mesmas se mantenham na atividade agropecuÃria assegurando a reproduÃÃo social dos agricultores num cenÃrio com financiamento do Pronaf. Os resultados das variÃveis ambientais avaliadas demonstram que a unidade de produÃÃo com cultivo orgÃnico apresenta maior sustentabilidade ambiental, uma vez que o solo encontra-se em condiÃÃes fÃsicas e quÃmicas mais satisfatÃrias para o desenvolvimento dos microrganismos.

Given the prominence of international trade in the globalized economy, large undesirable costs arise due to uncertainties in international transactions. The United Nations Convention on Contracts for the International Sales of Goods, Vienna, 1980 identifies some of these costs to be a product of separate legal rules on international trade, and recognizes the solution to lie in a unified statement of norms. Judicial experience with the Convention, however, has demonstrated that the existence of a unified statement of norms does not ensure uniform results. While the majority of the literature on the Convention takes a black letter law approach without examining the impact of varying interpretations on the end users of the Convention, this thesis argues that the provisions of the Convention, from the perspective of the parties, must operate to achieve the ends of efficiency. Absent the same, parties drafting a contract would opt out of the application of the default rules by including a provision in the contract governing the contingency. Such an outcome would in turn significantly increase transaction costs associated with contractual negotiating and drafting. This thesis concerns itself with six areas that have raised a great deal of disagreement amongst the scholarly and judicial community namely: The scope and role of the principle of good faith; the issues surrounding the inclusion of standard terms into the contracts of sale; the extent to which the Convention allows for the use of openprice terms; the question of the period within which notice of non-conformity must be provided; the rate at which interest has to be paid on sums in arrears and; the guiding principles for the interpretation of the term 'foreseeability' as contained in article 74. Each chapter of this thesis therefore deals with one of these issues and attempts to resolve it in line with the international character of the Convention - and one that promotes the efficiency of the agreement. For the purposes of this thesis, an efficient rule is defined as one that operates to minimize transaction costs, does not allow or de-incentivizes the potential of parties to act in an opportunistic manner and places liability on the best risk avoider. In reaching such an interpretation of the articles under examination, the thesis gives due regard to the travaux preparatoires, scholarly opinion and judicial pronunciations on the matter.

Multiliteracies theory extends the notion of literacy well beyond the traditional linear text-based definition of reading and writing (New London Group, 1996). It addresses the saliency of cultural and linguistic diversity and the multiplicity of communication channels and media available in our rapidly changing world. Multiliteracies involve engagement with multiple design modes, linguistic, visual, audio, gestural, spatial, and multimodal being a combination of the different modes. This research emerged from the need to open a space for students in an international languages school teaching Arabic language to engage in creative, aesthetic, alternative, and multimodal forms of literacy that involve the integration of the various semiotic resources in their meaning-making and design of texts. It is about a lived teaching-learning journey that draws on the concept of living pedagogy and dwelling in the in-between spaces of curriculum-as-plan and curriculum-as-live(d) (Aoki, 1991). In this research journey, I share the possibilities that opened up when students between the age of eleven and fourteen years old engaged with multiliteracies in an international languages classroom that teaches heritage language. This research journey also presents how the participative type of inquiry and collaboration between the researcher and classroom teacher contributed to the enhancement of their knowledge and learning about multiliteracies practices. After listening to and discussing a literary text presented by the teacher, students responded by creating their own texts to show their understanding of the narrative genre. They produced multimodal arts-based (Barton, 2014; Sanders & Albers, 2010) and digital based texts (Knobel & Lankshear, 2013). Through a multiliteracies/multimodalities theoretical, epistemological, and methodological perspective (Albers, 2007; Jewitt & Kress, 2008; Morawski, 2012; Rowsell, 2013), and drawing from approaches such as participatory action research (Chevalier & Buckles, 2013), and bricolage (Kincheloe, 2004), I developed this research story through a process of braiding and interweaving of various modes of texts and genres to produce a métissage (Hasebe-Ludt, Chambers, & Leggo, 2009) of the live(d) narratives of my research praxis. This inquiry offers a glimpse as to how opening the space for creative approaches in the teaching of literacy engages students in the design of texts using both linguistic and non-linguistic semiotic resources and incorporating multiple modes of representation from which they produce arts, digital, and multimodal texts.

A genetic algorithm using conventional heuristics as operators is considered in this study for the traveling salesman problem with backhauls (TSPB). Properties of a crossover operator (Nearest Neighbor Crossover, NNX) based on the nearest neighbor heuristic and the idea of using more than two parents are investigated in a series of experiments. Different parent selection and replacement strategies and generation of multiple children are tried as well. Conventional improvement heuristics are also used as mutation operators. It has been observed that 2-edge exchange and node insertion heuristics work well with NNX using only two parents. The best settings among different alternatives experimented are applied on traveling salesman problem with backhauls (TSPB). TSPB is a problem in which there are two groups of customers. The aim is to minimize the distance traveled visiting all the cities, where the second group can be visited only after all cities in the first group are already visited. The approach we propose shows very good performance on randomly generated TSPB instances.

6.1 INTRODUCCIÓ Des del 2001, el grup de Química Organometàl¿lica i Catàlisis Homogènia de la Universitat Jaume I, QOMCAT, dirigit pel professor Eduardo Peris, ha centrat els seus esforços en la investigació i desenvolupament de nous lligands de tipus carbè N-heterocíclics (NHCs) per a la preparació de catalitzadors metàl¿lics millorats. La versatilitat dels lligands de tipus NHC, a més de la fàcil preparació dels seus precursors (normalment sals d'azoli), han permès dissenyar una gran varietat de topologies i formes de coordinació. Dins d'aquest context, aquest grup va iniciar algunes línies d'investigació relacionades amb la 'Química Verda'. Així, nous complexos que contenien lligands NHC van ser sintetitzats per a la reducció de CO2 utilitzant iPrOH en lloc de H2, fent el procés més segur i respectuós amb el medi ambient. A més, la funcionalització de lligands NHC amb grups polars va permetre la síntesi de catalitzadors solubles en dissolvents sostenibles (aigua i glicerol),1-6 i també l'ús d'altres eines d'activació de calefacció d'energia alternativa (MW or US).4-5 Més recentment, el grup va reorientar els seus esforços en el disseny d'estructures rígides basades en lligands poli-NHC per a la preparació de catalitzadors homo- i heterometàl¿lics.7-10 Aquest tipus de policarbens poden estar units mitjançant sistemes rígids ¿-conjugats i poden ser capaços de comunicar electrònicament les unitats carbèniques. Aquesta característica dels complexos poli-NHC pot tindre molt d'interès per a la fabricació de dispositius electrònics moleculars a més de les importants millores catalítiques que pot implementar. A continuació s'inclou una breu ressenya sobre els avanços fets durant aquesta tesi doctoral: Disseny de catalitzadors per al desenvolupament de processos verds i síntesi de nous complexos basats en lligands imidazolilidè-piridilidè i poli-NHC. Els processos verds que decidírem estudiar són la reacció Suzuki-Miyaura d'acoblament C-C en aigua i l'alquilació d'amoníac amb alcohols primaris que transcorre a través d'un mecanisme de "préstec d'hidrogen", conegut més habitualment pel terme anglès Borrowing-Hydrogen. Les reaccions d'acoblament C-C catalitzades per metalls de transició són un dels mètodes més utilitzats per a la formació d'enllaços C-C, sent el pal¿ladi el metall més utilitzat per a desenvolupar aquest tipus de reaccions. Entre aquests processos, la reacció d'acoblament Suzuki-Miyaura, és a dir, l'acoblament entre un àcid arilborònic i un halur d'aril,11 és el protocol més utilitzat per a sintetitzar bifenils atesa la bona tolerància davant diferents grups funcionals. Per aquesta raò, trobar una alternativa més respectuosa amb el medi ambient per a dur a terme aquesta reacció és un repte per als investigadors en el camp de la catàlisi homogènia. Els processos catalítics que s'engloben sota el terme "Borrowing-Hydrogen" constitueixen un ampli ventall de reaccions en les que el nexe comú és determinat per la intermediació d'un catalitzador que serveix com a transportador d'hidrogen entre un parell de substrats.12-15 En una reacció típica de Borrowing-Hydrogen es produeix l'oxidació d'un substrat, normalment un alcohol (o una amina), per un catalitzador metàl¿lic que 'agafa com a préstec' dos àtoms d'hidrogen. Depenent si l'alcohol és primari o secundari, es generarà un aldehid o una cetona, respectivament. Aquests compostos de carbonil poden sofrir una àmplia gama de transformacions ja que poden reaccionar in situ per a donar imines, alquens i compostos de carbonil funcionalitzats. El catalitzador metàl¿lic, que havia agafat com a préstec l'hidrogen, el "torna" al nou compost, produint la seua reducció. Aquests processos catalítics compleixen el principi d'economia atòmica ja que, normalment, tots els àtoms dels substrats apareixen en els productes o, com a màxim, l'únic subproducte obtingut és H2O o NH3, per la qual cosa es consideren processos que contribueixen a la química verda. Els lligands de tipus imidazolilidè-piridilidè (C,C¿-imz-pyr) se formen com a conseqüència de la unió d'una unitat d'imidazolilidè i una unitat piridilidè. El primers complexos que presentaven aquest tipus de lligands (C,C¿-imz-pyr) foren descrits per Colbran,16 6.1 en Esquema 6.1. En els últims anys els lligands de tipus poli-NHC han donant lloc a una gran varietat de complexos polimetàl¿lics, amb diferents topologies que condueixen a l'obtenció de propietats catalítiques inusuals17-20 En aquest sentit, el nostre grup d'investigació ha descrit recentment lligands di- i tri-NHC amb sistemes ¿-electrònics conjuminats per a la preparació de compostos polimetàl¿lics millorats.8, 21 En particular, el lligand tri-NHC 6.2 (Esquema 6.2) va donar lloc a compostos que augmentaven la seua capacitat catalítica en comparació amb altres compostos mono metàl¿lics o tri metàl¿lics amb les mateixes característiques esteroelectròniques Hahn i col¿laboradors van ser els primers a descriure una estructura supramolecular metàl¿lica tridimensional que contenia exclusivament enllaços metall-NHC (6.3, Esquema 6.3).22 Aquesta estructura es va sintetitzar per reacció directa de dos lligands hexa-NHC amb Ag2O. En principi, aquest tipus d'estructures poden ser utilitzades com a caixes macromoleculars encercladores de molècules menudes neutres o iòniques i, per tant, funcionar com a detectors químics.23-28 En concret en el compost 6.3 es mostra la presència d¿un ió bromur a l¿interior de la caixa. 6.2 OBJECTIUS L'objectiu general d'aquesta tesi doctoral és la síntesi de catalitzadors homogenis amb propietats esteroelectròniques millorades. En aquest sentit, el treball es centra en la preparació i caracterització de nous complexos metàl¿lics amb diferents lligands de tipus carbè N-heterocíclic (NHC) o lligands anàlegs, l'estudi dels seus patrons de reactivitat i l'exploració de les seues propietats catalítiques. Els objectius concrets que se¿n deriven son els següents: ¿ Síntesi de complexos de pal¿ladi i iridi per al desenvolupament de processos verds. Principalment, s'intentaran realitzar reaccions catalítiques amb les condicions més respectuoses amb el medi ambient, utilitzant dissolvents no tòxics, amb la màxima economia atòmica i sense malbaratament d'energia. ¿ Estudi sistemàtic de la reactivat de lligands imidazolilidè-piridilidè mitjançant la seua coordinació a precursors de rodi i iridi. ¿ Disseny, síntesi i coordinació de lligands poli-NHC per a la preparació de complexos polimetàl¿lics amb estructures inusuals i altament simètriques. Estudi de les seues propietats electròniques. ¿ 6.3 DISCUSSIÓ DE RESULTATS 6.3.1 Síntesi de compostos de Pd(II) hidrofílics amb lligands NHC. Aplicacions catalítiques 6.3.1.1 Síntesi de compostos de Pd(II) hidrofílics amb lligands NHC L'Esquema 6.4, mostra els tres precursors dels lligands NHC, funcionalitzats amb cadenes sulfonatades, que han sigut utilitzats. El compost AH,3 ha sigut prèviament descrit en la bibliografia, mentre que, els compostos BH2 i CH2 s'han sintetitzat i caracteritzat per primera vegada al llarg del treball d'investigació que es presenta. A partir d'aquests lligands s¿han obtingut complexos de Pd(II) en els quals els lligands s'uneixen al metall de forma mono coordinada, quelat i pinça. Hem tractat que l'elecció d'aquest tipus de modes de coordinació donen lloc a un ampli conjunt de topologies de complexos de pal¿ladi NHC que ja han demostrat propietats catalítiques eficients en dissolvents orgànics.29-30 L'estratègia de metal¿lació utilitzada ha sigut l'ús d'una base dèbil incorporada en el precursor de pal¿ladi per a desprotonar els compostos d'imidazolilidè segons es mostra en l'Esquema 6.5. Els compostos d'imidazoli BH2 i CH2 junt amb els catalitzadors 1A-4C descrits en aquesta secció, han sigut sintetitzats per primera vegada al llarg del treball d'investigació que es presenta i han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. El complex 4C va ser sintetitzat, ja que la introducció d'un lligand piridina ha demostrat millorar l'activitat catalítica dels compostos amb els quals es coordina per efecte "PEPPSI".31-33 6.3.1.2 Aplicacions catalítiques Amb la finalitat d'avaluar les propietats catalítiques dels complexos hidrofílics preparats en l'apartat anterior, decidírem utilitzar-los en la reacció d'acoblament C-C de Suzuki-Miyaura en aigua, on un àcid arilborònic reacciona amb un halur d'aril per a donar un compost biarilat. Així, es va fer reaccionar l'àcid fenilborònic amb vuit halurs d'aril diferents (4-brom, i 4-cloracetofenona; 4-brom, i 4-clorbenzè; 4-brom, i 4-clortoluè; 4-brom, i 4-cloranisol), tal com es mostra en l'Esquema 6.6. Les reaccions es van fer en una mescla d'aigua/iPrOH (1:1) a 110ºC, amb 1 mol% de catalitzador i en presència de K2CO3. Els resultats obtinguts ens van permetre concloure que els compostos 1A i 3C són els més actius, ja que faciliten rendiments molt elevats en temps de reacció curts (4h, per als bromur d'aril i 12h, per als clorur d'aril). Però és el catalitzador 1A amb què obtenim els resultats més espectaculars quan utilitzem 4-bromacetofenona i 4-cloracetofenona, ja que obtenim rendiments superiors al 99% en 4h i 12h, respectivament. Els resultats catalítics obtinguts suggereixen que la presència del lligand piridina en el compost 4C no augmenta l'activitat catalítica d'aquest per efecte "PEPPSI" en comparació al catalitzador 3C. 6.3.2 Síntesi de compostos de Ir(III) amb lligands formamidina. Aplicacions catalítiques 6.3.2.1 Síntesi de compostos de Ir(III) amb lligands formamidina El lligand 1,3-bis(2,4,6-trimetilfenil)formamidina, D, va ser sintetitzat seguint el procediment descrit en la literatura34 i a partir d'aquest vam obtenir dos compostos diferents de 'IrCp*' depenent de la forma de coordinar-se d'aquest. Si el lligand D adopta coordinació monodentada s'obté el compost 5D, però si la coordinació es en forma quelat obtenim el compost 6D (Esquema 6.7). Aquests dos nous compostos, 5D i 6D, han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels dos compostos han sigut confirmades mitjançant Difracció de Raigs X (DRX) sobre monocristall. 6.3.2.2 Aplicacions catalítiques En aquest cas, decidírem comprovar l'activitat catalítica dels compostos 5D i 6D en dues reaccions governades per processos de Borrowing-Hydrogen. En primer lloc començàrem amb la reacció de ß-alquilació d'alcohols secundaris amb alcohols primaris per a després estendre l'estudi de l'activitat catalítica dels dos complexos en una reacció més interessant, com és l'alquilació d'amoníac amb alcohols primaris. a) ß-Alquilació d'alcohols secundaris amb alcohols primaris Aquesta reacció es va dur a terme en condicions de màxima economia atòmica, és a dir, intentant que tots els materials utilitzats com a reactius s'incorporen als productes. Així, tal com es mostra en l'Esquema 6.8, es va fer reaccionar una mescla equimolecular de l'alcohol primari, alcohol secundari i una base (KOH), en presència de 0.1-1 mol% de catalitzador en toluè a 100ºC. La reacció pot donar lloc a dos productes, l'alcohol alquilat i/o la cetona alquilada. La reacció es va dur a terme utilitzant 2-feniletanol com a alcohol secundari i quatre alcohols primaris diferents (bencilalcohol, butanol, 3-clorbencilalcohol i 4-clorbencilalcohol), utilitzant els catalitzadors 5D i 6D. Els resultats obtinguts van permetre concloure que 5D és molt més eficient que 6D, tant en termes de conversió cap als productes finals com en selectivitat cap a l'alcohol ß-alquilat. El catalitzador 5D també és molt actiu fins i tot a concentracions de 0.1 mol%, sobretot quan utilitzem bencilalcohol i 4-clorbencilalcohol. Els resultats catalítics obtinguts suggereixen que el grup NH en el lligand formamidina del complex 5D aporta un 'efecte NH'35-36 cooperatiu fent que aquest compost siga més actiu que 6D. b) Alquilació d'amoníac amb alcohols primaris En primer lloc vam comparar l'activitat catalítica de [IrCp*Cl2]2, el catalitzador d'Shvo i els nous compostos 5D i 6D. Com es mostra en l'Esquema 6.9, per a dur a terme la reacció es va fer reaccionar diferents sals d'amoni amb bencilalcohol a 110 o 130ºC, utilitzat diverses carregues de catalitzador, en presència d'un 3 mol% de NaHCO3 i amb proporcions de bencilalcohol/sal d'amoni de 3:1 o 3.6:1. El complex 5D i el catalitzador d'Shvo mostraren excel¿lents resultats catalítics en l'alquilació de la sal d'amoni NH4OAc per a obtindre trifenilamina, en comparació amb els resultats obtinguts amb [IrCp*Cl2]2 i el complex 6D sota les mateixes condicions de reacció. A més, 5D va ser moderadament actiu en l'alquilació del NH4OH. Tenint en compte les dades anteriors, decidírem ampliar l'abast del catalitzador d'Shvo i el complex 5D, estudiant la seva activitat catalítica davant una varietat d'alcohols primaris. Tal i com es mostra en l'Esquema 6.10, l'alquilació de sals d'amoni amb diferents alcohols primaris es va dur a terme a 130 o140ºC, utilitzant carregues de catalitzador d'1, 3 i 5 mol%, en presència de KOH o sense base i amb proporcions d'alcohol primari/sal d'amoni de 3.6:1 o 6:1. En aquest cas la reacció pot donar lloc a diferents amines, segons l'alcohol primari utilitzat (4-clorbencilalcohol, 3-clorbencilalcohol, 4-metilbencilalcohol, 1-hexanol, 1-butanol i 1-ciclohexanol). Els resultats obtinguts ens van permetre concloure que amb el catalitzador 5D s'obtenen resultats catalítics extraordinaris, sobretot quan utilitzem bencilalcohol, però, la seua eficiència baixa quan utilitzem alcohols alquílics. La activitat del catalitzador d'Shvo és en la majoria del casos més elevada, mostrant així la gran aplicabilitat d'aquest catalitzador exepcional. A la vista dels resultats obtinguts en les dues reaccions governades per processos de Borrowing-Hydrogen, i tal com havíem comentat anteriorment, creiem que la presència del grup NH en el lligand formamidina del complex 5D està incrementant l'activitat catalítica d'aquest davant el complex 6D i [IrCp*Cl2]2. Aquet 'efecte NH' pot estar facilitant la deshidrogenació de l'alcohol primari per a passar a aldehid en el primer pas del cicle catalític,37 d'una manera similar a les observacions descrites per Noyori en les reaccions d'hidrogenació de cetones.35-36 6.3.3 Síntesi de compostos de Rh(III) i Ir(III) basats en lligands imidazolilidè-piridilidè i estudi de la seua reactivitat no convencional Durant aquesta tesi doctoral també ens vam interessar en la síntesi de compostos de rodi i iridi amb lligands imidazolilidè-piridilidè (C,C¿-imz-pyr) coordinats en forma quelat. A més d'obtenir els compostos di-NHC esperats, també es varen sintetitzar una sèrie de compostos amb els lligands reordenats en formes poc convencionals. L'estudi d'aquests nous compostos amb lligands C,C¿-imz-pyr ofereix una bona oportunitat per a comparar les diferències estructurals i de reactivitat d'aquests complexos depenent del tipus de la coordinació del carbè (normal, abnormal o remota), tant del imidazolilidè com del piridilidè. L'Esquema 6.11 mostra les diferents sals precursores dels lligands C,C¿-imz-pyr que han sigut utilitzades. Totes aquestes sals s'han sintetitzat i caracteritzat, per primera vegada, al llarg del treball d'investigació que es presenta. 6.3.3.1 Síntesi i caracterització dels complexos [MI2(C,C'-imz-pyr)(CH3CN)2]+ (M = Rh, Ir) En primer lloc, vam obtenir una sèrie de complexos de tipus [MI2(C,C'-imz-pyr)(CH3CN)2]+ (M = Rh, Ir) (Esquema 6.13). L'estratègia sintètica per a sintetitzar estos compostos va consistir a fer reaccionar la sal d'imidazoli-piridini corresponent, [EH2]I2-[JH2]I2, amb el precursor metàl¿lic [MCl(diolefina)]2 (M = Rh, Ir; diolefina = COD, NBD) i KI en CH3CN a 65ºC durant 12h. Com a exemple la síntesi del compost 7E es mostra en l'Esquema 6.12. Les noves sals d'imidazoli-piridini, [EH2]I2-[JH2]I2, i els nous complexos metàl¿lics de Rh(III) i Ir(III), 7E-16I, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels complexos 11F, 14G i 15I han sigut confirmades mitjançant Difracció de Raigs-X sobre monocristall. L'avaluació de l'espectroscòpia de RMN d'aquests complexos revela algunes característiques que interessa mencionar. Pel que fa a l'espectroscòpia 13C RMN d'aquests compostos, es va observar que les freqüències degudes als carbens dels piridilidens decreixen en l'ordre: remot, normal, abnormal, per al rodi, i remot, abnormal per a l'iridi. Rodi: remot (¿c = 183.9) > normal (¿c = 175.7) > abnormal (¿c = 169.3) Iridi: remot (¿c = 164.7) > abnormal (¿c = 160.8) L'anàlisi de les longituds d'enllaç en les estructures moleculars del compostos 11F i 15I (Esquema 6.14) en han permès constatar que els piridilidens aporten una influència trans major que els imidazolilidens, com ja han suggerit altres grups d'investigació.38-39 6.3.3.2 Síntesi i caracterització dels complexos [MCp*I(C,C'-imz-pyr)]+ (M = Rh, Ir) Decidírem estendre la coordinació dels lligands derivats de les sals, [EH2]I2, [GH2]I2 i [IH2]I2, a altres precursors metàl¿lics com són [MCp*Cl2]2 (M = Rh, Ir) i una sèrie de compostos [MCp*I(C,C'-imz-pyr)]+ (M = Rh, Ir) foren sintetitzats (Esquema 6.16). L'estratègia sintètica per a sintetitzar estos compostos és similar a la utilitzada anteriorment, però en aquest es va afegir base i es va calfar a 90ºC durant 12h. Com a exemple la síntesi del compost 17E es mostra en l'Esquema 6.15. Els nous complexos metàl¿lics de Rh(III) i Ir(III), 17E-24I, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels complexos 18E, 19E, 20E, 22G i 23I han sigut confirmades mitjançant Difracció de Raigs-X sobre monocristall. Els compostos 20E, 22G i 23I presenten reactivitats molt inusuals. En el cas de 20E, l'imidazolilidè esta coordinat al centre metàl¿lic mentre que el piridilidè esta acoblat a l'anell de Cp*, així s'obté un anell Cp* funcionalitzat amb un imidazolilidè penjant. Pel que fa al compost 22G, a més de l'activació C-H esperada del CH3 del C2 de l'imidazoli un acoblament reductiu entre el Cp* i l'anell de piridini te lloc. Tant en el cas del complex 20E com per a 22G, creiem que aquests dos compostos se generen via la formació d'un intermedi de tetrametilfulvè de rodi. Tal com s'ha descrit per a compostos amb reactivitats similars.40-45 El compost 23I és un dímer d'iridi en el qual l'obertura de l'anell d'imidazoli ha tingut lloc com a conseqüència de la hidròlisi de l'imidazolilidè. La hidròlisi de carbens no és un fet tant estrany i ha sigut descrit en més ocasions.46 En el nostre cas, a banda de l'obertura de l'anell d'imidazolilidè, es produeixen altres reorganitzacions que tenen a veure amb la descarboxilació de l'aldehid per a generar el lligand carbonil i el lligand imino. 6.3.4 Síntesi de compostos de Rh(I) Ag(I) i Au(I) basats en lligands poli-NHC Durant aquesta tesi doctoral, també hem centrat els nostres esforços en sintetitzar compostos que contenen lligands poli-NHC. En primer lloc, varem sintetitzar i coordinar un lligand tri-NHC amb una estructura central basada en un tribenzotriquinacè (TBTQ) i amb simetria C3v a Rh(I). La segona família de compostos es va obtenir a partir de dues sals d'hexa-imidazoli, els lligands derivats d'elles es varen coordinar a Ag(I) obtenint complexos amb sis àtoms de plata en forma cilíndrica. Els compostos d'or anàlegs també es varen obtenir mitjançant transmetal¿lació. 6.3.4.1 Síntesi i caracterització del complex de Rh(I) amb el lligand tri-NHC-TBTQ L'estratègia sintètica per a preparar compostos amb lligands poli-NHC comença amb l'aminació múltiple de Buchwald-Hartwig de molècules poliaromàtiques amb bromurs adjacents. Aquesta metodologia ha sigut utilitzada per Bielawski i col¿laboradors i nosaltres aplicàrem aquesta metodologia a hexabromtribenzotriquinacè 6.547 (Esquema 6.17). D'aquesta manera, tal com es mostra en l'Esquema 6.17, el compost 6.5 reacciona amb tert-butilamina (tBuNH2) en presència de [Pd(OAc)2], IPr¿HCl i NaOtBu en toluè a 115ºC, per a donar hexaaminotribenzotriquinacè, hexaNH2-TBTQ, que posteriorment es ciclat amb trietilortoformat (HC(OEt)3) en presència de HBF4 a 80ºC, obtenint-se la sal [KH3](BF4)3. Aquesta sal es desprotonada amb KHMD en THF a 0ºC, i amb la posterior addició de [RhCl(COD)]2 a temperatura ambient s'obté el complex 25K que es purificat mitjançant cromatografia de columna. Els nous compostos, hexaNH2-TBTQ, [KH3](BF4)3 i 25K, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN i espectrometria de masses. L'estructura molecular de [KH3](BF4)3 ha sigut confirmada mitjançant Difracció de Raigs-X sobre monocristall. 6.3.4.2 Síntesi i caracterització de complexos de Ag(I) i Au(I) amb lligands hexa-NHC Amb la finalitat d'augmentar el nombre d'estructures supramoleculars generades a partir de lligands poli-NHC, pensàrem que les sals 1,2,3,4,5,6-hexa(N-alquil imidazoli)benzè [LH6](OTf)6 i [MH6](BF4)6 (alquil = Me i Et, respectivament) (Esquema 6.18), podrien ser bones precursores. Aquestes sals s'obtenen a partir de l'alquilació de hexa(imidazol-1-il)benzè amb metil trifluorometasulfonat per a donar [LH6](OTf)6, o amb trietiloxoni tetrafluoroborat per a donar [MH6](BF4)6 (Esquema 6.18). La reacció d'aquestes dues sals amb Ag2O en CH3OH a 50ºC dona lloc als corresponents complexos cilíndrics, 26L i 27M, que contenen sis centres de Ag(I). Els compostos anàlegs d'or, 28L i 29M, s'obtenen mitjançant la reacció de 26L i 27M en CH3OH a 50ºC i en presència de AuCl(SMe2) (Esquema 6.18). Les noves sals, [LH6](OTf)6 i [MH6](BF4)6 i els nous complexos 26L, 27M, 28L i 29M, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN i espectrometria de masses. L'estructura molecular de 28M ha sigut confirmada mitjançant Difracció de Raigs-X sobre monocristall. ¿ 6.4 CONCLUSIONS En aquesta tesi doctoral s'han obtingut una sèrie de complexos de pal¿ladi amb lligands NHC hidrofílics i complexos d'iridi amb el lligand formamidina. Aquests complexos han sigut avaluats en processos verds com són la reacció Suzuki-Miyaura d'acoblament C-C en aigua i les reaccions governades per processos de Borrowing-Hydrogen: ß-alquilació d'alcohols secundaris amb alcohols primaris i alquilació d'amoníac amb alcohols primaris. El compost 3C ha sigut el més actiu en la reacció Suzuki-Miyaura d'acoblament C-C en aigua i el compost 5D, junt amb el catalitzador d'Shvo, han presentat les millors activitats en les reaccions governades per processos de Borrowing-Hydrogen. Durant aquesta tesi doctoral, també s'han sintetitzat compostos de Rh(III) i Ir(III) amb lligands imidazolilidè-piridilidè que han presentat reactivitats molt inusuals. La comparació entre els diferents compostos obtinguts ens ha permès determinar que els piridilidens ocasionen un major efecte trans que els imidazolilidens. Finalment, s'han sintetitzat dos lligands nous poli-NHC per a la preparació de complexos polimetàl¿lics amb estructures altament simètriques. La possibilitat de preparar complexos homo-polimetàl¿lics suggereix que prompte podrem trobar la via per a sintetitzar espècies hetero-polimetàl¿liques. Per la nostra experiència, aquests complexos solen ser potencialment útils per al disseny de nous processos catalítics tàndem. A més, una de les propostes que ens hem plantejat és la combinació dels lligands piridilidens amb estructures politòpiques que obri una nova línea d'investigació dins del camp dels carbens N-heterocíclics.

Cette thèse de doctorat porte principalement sur la dynamique et la robustesse d’un nouveau concept de verrouillage de mode dans les nanolasers semi-conducteurs ultracompacts. Un tel nanolaser présente des modes ermites-gaussiens créés par une cavité photonique harmonique pour confiner la lumière. Cela permet de mapper la cavité optique en oscillateur harmonique de mécanique quantique, avec des fréquences propres régulièrement espacées, une condition essentielle pour le verrouillage de mode. La période de verrouillage de mode est contrôlée par la conception du potentiel photonique, et non par la longueur de la cavité. Les régimes non linéaires possibles sont décrits par l’équation de Gross-Pitaevskii avec un potentiel parabolique et des termes non linéaires décrivant le gain et l’absorption. Pour étudier ces comportements dynamiques, des simulations numériques directes sont principalement mises en œuvre. Tout d’abord, la compétition de mode pour le gain entre les modes ermites et gaussiens en l’absence d’absorption saturable est étudiée. Deuxièmement, on prévoit que le verrouillage des modes se produira avec une saturation instantanée du gain et de l’absorption sur un large éventail de paramètres, correspondant à l’émergence d’une soliton dissipative. Troisièmement, dans le régime de saturation non instantanée du gain et de l’absorption, différents comportements dynamiques du nanolaser sont obtenus en faisant varier le gain et l’absorption. Ces différents régimes, y compris la commutation Q, le verrouillage de mode à commutation Q et le verrouillage de mode CW, sont décrits en détail. L’influence du facteur Henry sur le verrouillage de mode est également abordée. Quatrièmement, la robustesse du verrouillage de mode des modes ermite et gaussien au désordre de la cavité harmonique est étudiée en détail, y compris l’effet de la non-parabolicité du potentiel et les erreurs aléatoires dans la forme du potentiel
This PhD thesis mainly addresses the dynamics and the robustness of a novel concept of mode locking in ultracompact semiconductor nanolasers. Such a nanolaser exhibits Hermite-Gaussian modes created by a harmonic photonic cavity to confine light. This maps the optical cavity into quantum mechanical harmonic oscillator, with evenly spaced eigenfrequencies, an essential requirement for mode locking. The possible nonlinear regimes are described by the Gross-Pitaevskii equation with a parabolic potential and nonlinear terms describing gain and absorption. To investigate these dynamical behaviors, direct numerical simulations are mainly implemented. Continuation calculations are also performed using pde2path.First, the mode competition for gain among Hermite-Gaussian modes in the absence of saturable absorption is investigated and shown to be very different from usual resonators.Second, mode locking is predicted to occur with instantaneous saturation of gain and absorption over a broad range of parameters, corresponding to the emergence of dissipative soliton and multisoliton solutions. The mode locking period is controlled by the design of the photonic potential, and not by the cavity length. The dissipative soliton is well described by the coherent state of a quantum mechanical oscillator, namely a Gaussian envelope oscillating without deformation.Third, in the regime of noninstantaneous gain and absorption saturation, different dynamical behaviors of the nanolaser are obtained by varying the gain and the absorption. These different regimes, including Q-switching, Q-switched mode locking, and CW mode locking, are described in detail, illustrating the rich physics of this nonlinear system. The influence of the Henry factor on the mode locking is also discussed. Moreover, similar dynamical behaviors using spatially separated gain and absorber sections inside the cavity are obtained.Fourth, the robustness of mode locking of the Hermite-Gaussian modes to the disorder of the harmonic cavity is investigated in details. It includes the effect of non-parabolicity of the potential and the random errors in the shape of the potential

In any underground facilities especially tunnels, it is essential to seal the area against water ingress and leakage of reserved materials. Grouting is a common method used to seal rocks around tunnels, successful grouting reduces the duration and cost of the construction, guarantees better working environment and higher safety, minimizes the maintenance and most important decreases the corresponding environmental hazards significantly. Achieving a sufficient grout spread is one of the prerequisites for a successful and efficient sealing, the penetration of a grout is defined as the length of how far grout penetrates in the rock through fractures from a bore hole. Chemical grouts and cement-based grouts are the prevailing ones among the grouting materials. Despite the better penetrability of chemical grouts, they are unfavorable to use due to environmental hazards associated to them, whilst cement-based grouts are more convenient to use because of their low cost and low environmental impact.The major drawback with cement-based grouts is their limited ability to penetrate the very narrow fractures which is directly related to their filtration tendency which is defined as the tendency of cement grains to agglomerate and build an impermeable filter cake during the flow. Many previous studies investigated the factors that affect the filtration tendency. They drew different conclusions and suggested various methods to improve the penetrability of cement-based grouts.The mixing method is one of the factors that have a great influence on the penetrability of the grout. An effective mixing method improves the dispersion of cement particles in the mixture, thus the penetrability of the grout. As it is known from previous studies, the finer the cement particles the harder to disperse. Grouts based on micro-fine cement (< 30 μm) are essential for the development of grouts that can seal very narrow fractures (20-50) μm compared to (70-80) μm at the present.In this study, the dispersion efficiency of three different mixing methods was evaluated, a conventional lab dissolver equipped with 90-mm disk, a conventional lab dissolver equipped with R/S system and an ultrasound UP400St device. Two cement types, INJ30 and UF12, that are similar in chemical composition but differ in degree of milling were tested. Dispersion was tested with filter pump.The results showed that the conventional lab dissolver equipped with 90-mm disk is ineffective method. The conventional lab dissolver equipped with R/S system is a better method compared to the 90-mm disk but still not effective enough especially when it comes to grouts based on ultra-fine cement (UF12). The ultrasound dispersion is not only the best method between the three methods in comparison, but even more stable and reliable. The best result obtained was grout based on UF12 passing through the 54 μm filter. This could mean that fracture aperture down to 55 μm now can be sealed. This is a significant improvement but there is still a marginal for further improvements. In combination with the dispersion efficiency of different dispersion methods, the study investigated the effect of additives on dispersion in particular and penetrability in general. Results showed that additives do not directly contribute to better dispersion, but they are necessary for better spread since they affect the flow properties.

Innovations in information technology have played an important role in the way business is conducted. Technology innovations have great impact on tourism destination marketing organizations such as convention and visitor bureaus, since they are highly dependent on information and timely distribution of it to the public. Information technology innovations such as the Internet allow CVBs to perform their marketing functions in a more efficient manner. The implementation of web-based marketing functions is impacted by organizational characteristics that either foster or hinder their implementation (Thong, 1999; Tornatzky & Fleischer, 1990; Wang & Fesenmaier, 2006; Zhu & Kraemer, 2005). Information technology innovations have been adopted by organizations in different levels of sophistication. Since the main function of a CVB is the promotion of a destination technologies that facilitate this process are important to this type of organization. Unfortunately, the marketing practice of American CVBs is still dominated by principles of mass marketing by communicating the same message to all consumers. As a result, the use of websites by American CVB has been limited to information provision functions and has lost opportunities to build relationship with customers through additional web-based marketing activities. This study proposes that CVBs should use web-based marketing activities to attract and retain relationships with customers. This study provides two main contributions to the existing literature: a) examines web-based marketing functions from a relationship marketing perspective and b) examines the impact of organizational characteristics on the sophistication level of web-based marketing functions. The use and effectiveness of web functions and its applications were examined. The results showed that the majority of the CVBs focus the use of their website to provide information. A standard multiple regression was used to investigate the impact of the organizational factors on the different web functions. The results of the regression show that size, financial resources and management team's technological expertise are the only factors that impact the level of web functions implemented by CVBs.
M.S.
Other
Rosen College of Hospitality Management
Hospitality and Tourism Management

This thesis investigates States Parties' implementation of the 1972 UNESCO Convention concerning the Protection of the World Cultural and Natural Heritage. Its objectives are two-fold. The first of these is the quantitative and qualitative analysis of the evolution of the values for which cultural heritage sites have been nominated for World Heritage status in relation to the decisions of the World Heritage Committee across different categories of cultural heritage. The second objective is the examination of States Parties' representations of the past and the nation, of human and cultural diversity, of economic value, and of authenticity and conservation by means of an evaluation of sampled nomination dossiers of cultural heritage sites for inclusion on the World Heritage List. The thesis methodology is based on intensive archival work of UNESCO documents as well as value-led analyses of one hundred and six purposefully sampled nomination dossiers. ATLAS. ti, a Computer Assisted Qualitative Data Analysis Software program, was used for the quantitative and qualitative analyses and interpretation of the sampled data set. The end result has been to identify how States Parties have understood the notion of outstanding universal value which is the key and central concept of the World Heritage Convention. It has also been to highlight the problems in States Parties' implementation of the World Heritage Convention and in the requested format of nomination dossiers. This has led to practical changes to official discourses on World Heritage and suggestions for procedural improvements. These changes and suggestions should help States Parties to identify better the values for which sites are being nominated for World Heritage status and improve their long-term conservation and management.

In this thesis the radar target tracking problem in Bayesian estimation framework is studied. Traditionally, linear or linearized models, where the uncertainty in the system and measurement models is typically represented by Gaussian densities, are used in this area. Therefore, classical sub-optimal Bayesian methods based on linearized Kalman filters can be used. The sequential Monte Carlo methods, i.e. particle filters, make it possible to utilize the inherent non-linear state relations and non-Gaussian noise models. Given the sufficient computational power, the particle filter can provide better results than Kalman filter based methods in many cases. A survey over relevant radar tracking literature is presented including aspects as estimation and target modeling. In various target tracking related estimation applications, particle filtering algorithms are presented.

Sustainability can be described as a developmental approach whose focus is to integrate economic activity with social security and environmental protection. Sustainability of chemical process involves the use of sustainable practices in the chemical industry. Sustainability assessment describes the methods used for achieving sustainability in industries, it is needed because unsustainable practices can be tracked and corrected and also to track progress made by the company in achieving sustainability. The aim of this thesis was to use a green chemistry based sustainability assessment tool to compare one conventional and two CO₂ utilization routes in order to find the more sustainable way of producing formic acid and to suggest methods for improving the tool. The three routes considered in this work were the conventional route, which was done on a commercial scale. This method of producing formic acid is via methyl formate hydrolysis. The experimental route and the BP patented routes represented CO₂ utilization routes on laboratory scale setting and commercial setting respectively. These methods for producing formic acid involved the hydrogenation of CO₂. Another aim of this thesis was to review some currently used assessment tools related to sustainability. Six currently utilized assessment tools related to sustainability were compared based on their strengths and weaknesses and evaluated. Sustainability assessment was conducted on the three formic acid production routes based on the green chemistry assessment tool using the most important features. Sustainability assessment questionnaire based on the twelve green chemistry principles was used to assess the three formic acid production routes. The strengths and weakness of the green chemistry tool were discussed and recommendations for improving the tool were suggested. One way of improving the tool is to merge it with LCA in order to assess every stage of a product’s life cycle from cradle to grave. The results from the assessment showed that the conventional route was harmful to the environment while the CO₂ utilization routes were beneficial to the environment. The social section of the result showed that both the conventional and CO₂ utilization routes were socially unsustainable and the economic section of the results showed that the conventional and the CO₂ utilization routes were economically viable but the CO₂ utilization routes were more economically viable than the conventional route. Overall, the experimental CO₂ utilization route is the most sustainable way to produce formic acid. It is important that more research will be done on CO₂ utilization method of producing formic acid in order for it to fulfill its potential as a sustainable method.

Mestrado Vinifera Euromaster - Viticulture and Enology - Instituto Superior de Agronomia
Among the various enological products authorized by the European legislation, metatartaric acid (MTA) and carboxymethyl cellulose (CMC) are the most widely used to prevent tartrate salts instability, although showing some drawbacks concerning long-term efficacy the former, and colour instability the latter. Recently, an additive based on potassium polyaspartate (KPA) has been evaluated with regards to tartaric stabilisation, to obtain the admission of its use by the European Commission in 2017. The following thesis project developed at the Research Centre of Laimburg (Italy) aims to test the stabilisation effectiveness of potassium polyaspartates (KPA) on local red and white wines, in comparison with the two most widely used additive agents (MTA and CMC) and a subtractive technique (cold stabilisation). Analysis of stability were carried out over a period of six months, as well as chemical-physical parameters (turbidity, tartaric acid, chromatic characteristics) and sensory evaluations of each treatment. Statistical analysis between all trials’ results confirmed the importance of time in recognising the different performances of the used additives aimed to inhibit the crystallisation process of tartaric acid salts, whose behaviour produced different responses with regard to tartrate stability, turbidity and sensory profile. Best results were observed in wines treated with potassium polyaspartate (KPA) and cold stabilisation, although the latter is considered to bring some drawbacks related to operating costs, thus sustainability. Storage temperature effect (35°C) on the different treatments was also evaluated, obtaining again good responses from the polyaspartate based product, although depending on the dose applied. Sensory evaluation confirmed that the debate is still current, expressing greater preference towards cold stabilisation rather than any additive treatment
N/A

Unlike in oil firing, the effective role of additives to alleviate deposition in coal fired power generation is still regarded with much scepticism and controversy amongst the power generators and boiler operators. The objectives of this research study were principally to explore the mechanisms involved in formation of coal ash deposits and thus determine the effectiveness of a magnesium based additive, namely Lycal 93HS, in reducing the bonding strength of ash deposits on boiler tube surfaces, by making them friable and easily removed by sootblowers during normal operation of the boiler. The experimental techniques developed involved visual, optical and scanning electron microscopy examination of a wide range of matured deposit samples collected over a period of two years, with and without injection of Lycal 93HS into the boilers at West Belfast power station. Specimen deposit samples "fashioned" into the form of Seger cones and "reconstituted" from their crushed, powder form were tested for their softening behaviour at elevated temperatures with and without further additions of Lycal 93HS. This technique was further used to evaluate the effect of Lycal 93HS on the softening behaviour of a range of coal ash components separated by high temperature ashing of coarse particles of coal as well as the bulk ash from the coarse and fine sizes of coal particles. The softening behaviour on heating and crystallisation tendency behaviour on cooling for a selected range of the ash components was investigated without and with additions of Lycal 93HS, using Hot-Stage Microscopy. The possibility of surface adhesion between the fly ash and injected Lycal 93HS within the boiler environment was investigated through a series of laboratory based Surface leaching experiments of deposit and particulate samples with and without injection of Lycal 93HS. The variation in concentration profiles of silicon, iron and magnesium within the collected solutions over a period of time were analysed, using Atomic Absorption Flame Spectroscopy. The elemental chemical composition of bulk deposit samples, the average high temperature ash and its separated components was carried out using X-Ray Fluorescence. Qualitative study of the mineralogy of low temperature ash, selected ash components, as well as a range of deposit samples with Lycal injection was conducted using X-Ray Diffractometry. The results of Lycal injection into a boiler were clearly evident from inspections of the boiler where Lycal injection over different periods of time had resulted in significantly cleaner boiler tube surfaces. Examination of deposit samples with Lycal injection showed lightly sintered, porous, friable textures compared to the highly sintered, fused and dense structures for samples without Lycal injection. The effect of Lycal on the softening behaviour of reconstituted deposit samples and various components of ash was shown to be dependent on their chemical composition, with iron oxide playing an important role. For a number of highly acidic ash components, additions of 5 and 10 mass% Lycal promoted crystallisation of their fluid melt, when cooled to specific temperatures. For the more ferriferous ash components, additions of 1 and 3 mass% Lycal enhanced the surface formation of spikes when their melts were cooled to specific temperatures. The results of leaching experiments showed that the initial magnesia concentrations were generally much higher for the deposit samples and fly ash particles from ash hoppers and grit arrestors with Lycal injection than those without.

La croissance constante du droit conventionnel de l'environnement, que ponctuent les conferences de stockholm et de rio, s'articule avec la mise en place correlative de constructions institutionnelles dont la designation officielle (<< reunion des parties contractantes >>, << commission >>, << comite >>, etc. ) ne permet guere de deviner la nature juridique. Il est neanmoins possible de soumettre ce vaste ensemble a une classification fondee simultanement sur les caracteres organiques desdites institutions et sur l'etendue de leur personnalite juridique internationale. Cette demarche repose plus precisement sur l'examen de l'organe administratif, et amene a reconnaitre l'existence d'un lien etroit entre l'existence d'un secretariat independant et le benefice d'une personnalite internationale concue dans sa dimension objective. Il est de la sorte possible d'opposer les mecanismes institutionnels dont la conformation organique autorise le benefice d'une large mesure de personnalite internationale, et les organismes dont la structure ne saurait emporter un effet semblable. Cette distinction transcende l'opposition, plus apparente que reelle, entre les reunions et conferences d'etats partiesa un instrument conventionnel, et les entites a priori plus elaborees que sont les commissions, comites et organisations internationales proprement dites. Cette classification, si elle n'est pas sans rapports avec les modalites de la necessaire rationalisation qu'impose le foisonnement des constructions organiques etudiees, n'emporte en revanche que peu de consequences quant aux fonctions qui leur reviennent. Les taches en question concernent, dans l'extreme majorite des cas, le traitement et la gestion de l'information (concue comme une modalite privilegiee du controle) et la production de droit derive.

Thesis (B.Sc)--University of Hong Kong, 2007.
"A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2007." Includes bibliographical references (p. 26-28). Also available in print.

Thesis (B.Sc)--University of Hong Kong, 2007.
"A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2007." Includes bibliographical references (p. 27-30). Also available in print.

The increasing capabilities of multimedia appliances demand arithmetic circuits with higher speed and reasonable power dissipation. A common technique to attain those goals is synchronous pipelining, which increases the throughput of a circuit at the expense of longer latency, and it is therefore suitable where throughput takes priority over latency. Two synchronous pipelining approaches, conventional pipelining and wave pipelining, are commonly employed. Conventional pipelining uses registers to divide the circuit into shorter paths and synchronize among sub-blocks, while wave pipelining uses the delay of combinational elements to perform those tasks. As wave pipelining does not introduce additional registers, in principle, it can attain a higher throughput and lower power consumption. However, its throughput is limited by delay variations, while delay balancing often leads to increased power dissipation. This dissertation proposes a hybrid pipelining method called HyPipe, which divides the circuit into sub-blocks using conventional pipelining, and applies wave pipelining to each sub-block. Each sub-block is derived from a single base circuit, leading to a better delay balance and greater throughput than with heterogeneous circuits. Another requirement for wave pipelining to achieve high speed is short signal rise and fall times. Since CMOS wide-NAND and wide-NOR gates exhibit long rise and fall times and large delay variations, they should be decomposed. We show that the straightforward decomposition using alternating levels of NAND and NOR gates results in large delay variations. Therefore, we propose a new decomposition method using only one gate type. Our method reduces delay variations by up to 39%, and it is appropriate for wave pipelining based on standard-cells or sea-of-gates. We laid out a 4x4 HyPipe multiplier as a proof of concept and performed a post-layout SPICE simulation. The multiplier achieves a throughput of 4.17 billion multiplications per second or a clock period of 2.52 four-load inverter delays, which is almost twice the speed of any existing multiplier in the open literature. When the supply voltage is reduced to 1.2 V from 1.8 V, its power consumption is reduced from 76.2 mW to 18.2 mW while performing 2.33 billion multiplications per second.
Ph. D.

A considerable amount of research has shown traditional illicit drug policies represent a critical source of inequity and ongoing health-related harms on a global scale. The harms associated with these policies have spurred several calls for “evidence-based” policy reform whereby policies that criminalize drug users be replaced with public health approaches. These calls for policy reform, and the persistence of criminal justice based approaches, have raised questions about the strategies and tools scientists, researchers, academics and/or health practitioners may mobilize to support this objective (herein referred to collectively as scientists). In this context, the primary objectives of this thesis were to: 1) synthesize what is known about conventional activities and strategies scientists use to advance evidence-based drug policies and 2) to describe and evaluate in detail the Vienna Declaration campaign, the largest scientist-led mobilization to support evidence-based illicit drug policy to date, and 3) to generate insights into strategies that may support the advancement of evidence-based illicit drug policy, especially as they related to public and political discourse. This work reveals scientist-led efforts to promote evidence-based drug policy have not traditionally made use of the Internet and related tools. Findings from an analysis of the Vienna Declaration campaign reveal that the Internet and social media are important dissemination tools that support science-based efforts to advance evidence-based drug policy. Given the deficit of research in this area and long-standing limitations to scientists’ proficiency engaging the public, media, and policymakers, the thesis concludes additional research is needed to better understand the tools and strategies available to scientists working in this area. It speculates that such a research agenda may also serve as a culturally appropriate way of engaging scientists and influencing their future knowledge translation efforts.
Graduate and Postdoctoral Studies
Graduate

The study reported in this dissertation compares the learning effectiveness of two experimental methods that can be used in the teaching of kinematics to Grade 11 learners in Physical Science. The first method is the conventional ticker-timer experiment, while the second utilises high-technology microcomputer-based equipment. The purpose is to make recommendations for improved teaching of basic kinematics concepts and graphs, which learners have difficulties with (Halloun & Hestenes, 1985; McDermott et al., 1987). A group of 48 Grade 11 learners from Thuto-Boswa Secondary School, Ventersdorp, were used in the empirical research. They were divided into two groups of comparable abilities. Group A used the conventional apparatus and group B the microcomputerbased apparatus. The results of the pre- and post-tests were analysed statistically to compare the learning effectiveness of the two methods in terms of the outcomes reached, the gains obtained as well as d-values. Three months after the experiments were conducted the learners were tested again to determine the long-term effect of the methods. Both groups obtained a gain of approximately 0,2 in the pre- versus post-test analysis. The literature (e.g. Thornton, 1998) reveals larger gains with microcomputer-based experiments. Three possible reasons that could contribute to this discrepancy were investigated, namely the learners' acquaintance with the microcomputer, the educator's experience with the apparatus as well as the learners' cultural background and language. All three these factors were found to have a detrimental effect on the learning effectiveness, especially with the microcomputer-based method. Recommendations are made in connection with the teaching of basic kinematics concepts and graphs to Grade 11 learners in South African secondary schools. In addition, it is emphasised that educators should be adequately computer literate before expensive high-technology equipment is purchased for classroom use. It is also pointed out that the implementation of the computer as teaching aid can be a first step to improve computer literacy of disadvantaged learners in our schools.
Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2004.

L’objet de cette thèse est d’étudier les conditions de formation du taux d’intérêt des crédits bancaires et la pratique actuelle de sa variabilité. Elle comporte donc une analyse des grandes fonctions du taux d’intérêt et de ses principaux « déterminants » (en particulier le coût du financement). Elle recherche et précise les conditions de validité (de forme et de fond) de sa fixation conventionnelle : stipulation écrite, expression sous la forme d’un « taux effectif global », remise éventuelle d’une offre préalable, tout en mettant en relief les difficultés qu’elles soulèvent parfois pour la profession. Elle s’attache enfin à la pratique de la variabilité du taux conventionnel dont elle souligne l’universalité (en droit comparé comme en droit interne) étroitement liée à ses fondements économiques, et dont elle étudie les modalités d’application dans toute leur diversité, les limites que lui fixent la loi, al convention elle-même, voire le rappel par la jurisprudence de quelques principes généraux du droit, et les problèmes juridiques et commerciaux qu’elle pose aux établissements prêteurs.

Thesis (M.S.)--University of Toledo, 2009.
"In partial fulfillment of the requirements for the degree of Master of Science in Biomedical Sciences." Title from title page of PDF document. Bibliography: p. 34-35.

Cette thèse propose une méthode de navigation fondée sur les risques, y compris à la fois la notion traditionnelle de risque de collision et la notion de risque de perturbation. Avec la demande croissante d'assistance à la mobilité personnelle et de la robotique de services mobiles, les robots et les gens doivent partager les mêmes espaces physiques et suivre les mêmes conventions sociales. Les robots doivent respecter les contraintes de proximité, mais aussi respecter les gens qui interagissent. Par exemple, ils ne doivent pas briser l'interaction entre les gens qui parlent, à moins que la tâche du robot est de prendre part à la conversation. Dans ce cas, il doit être en mesure de rejoindre le groupe à l'aide d'un comportement socialement adapté. Le système de navigation socialement conscient proposée dans cette thèse intègre à la fois l'évaluation d'un risque de collision en utilisant des modèles prédictifs d'obstacles mobiles, et une évaluation de conformité avec les conventions sociales. La gestion humaine de l'espace (espace personnel, o-espace, espace d'activité ...) inspirée de la sociologie et la littérature robotique sociale est intégré, mais aussi des modèles de comportement qui permettent au robot la realisation de une prédiction à moyen terme des positions de l'homme. Les résultats de la simulation et des expériences sur un fauteuil roulant robotisé donnent validite a la méthode en montrant que notre robot est capable de naviguer dans un environnement dynamique en évitant les collisions avec des obstacles et des personnes et, en même temps, en réduisant l'inconfort chez les personnes en respectant les espaces mentionnés ci-dessus
This thesis proposes a risk-based navigation method including both the traditional notion of risk of collision and the notion of risk of disturbance. With the growing demand of personal assistance to mobility and mobile service robotics, robots and people must share the same physical spaces and follow the same social conventions. Robots must respect proximity constraints but also respect people interacting. For example, they should not break interaction between people talking, unless the robot task is to take part in the conversation. In this case, it must be able to join the group using a socially adapted behavior. The socially-aware navigation system proposed in this thesis integrates both an assessment of a risk of collision using predictive models of moving obstacles, and an assessment of accordance with social conventions. Human management of space (personal space, o-space, activity space...) inspired from sociology and social robotics literature is integrated, but also models of behavior that enable the robot to make medium-term prediction of the human positions. Simulation and experimental results on a robotic wheelchair validate the method by showing that our robot is able to navigate in a dynamic environment avoiding collisions with obstacles and people and, at the same time, minimizing discomfort in people by respecting spaces mentioned above

BACKGROUND: Practitioners of complementary and alternative medicine (CAM) therapies are an important and growing presence in health care systems worldwide. A central question is whether evidence-based behavior change interventions routinely employed in conventional health care could also be integrated into CAM practice to address public health priorities. Essential for successful integration are intervention approaches deemed acceptable and consistent with practice patterns and treatment approaches of different types of CAM practitioners - that is, they have context validity. Intervention development to ensure context validity was integral to Project CAM Reach (CAMR), a project examining the public health potential of tobacco cessation training for chiropractors, acupuncturists and massage therapists (CAM practitioners). This paper describes formative research conducted to achieve this goal. METHODS: Intervention development, undertaken in three CAM disciplines (chiropractic, acupuncture, massage therapy), consisted of six iterative steps: 1) exploratory key informant interviews; 2) local CAM practitioner community survey; 3) existing tobacco cessation curriculum demonstration with CAM practitioners; 4) adapting/tailoring of existing curriculum; 5) external review of adaptations; 6) delivery of tailored curriculum to CAM practitioners with follow-up curriculum evaluation. RESULTS: CAM practitioners identified barriers and facilitators to addressing tobacco use with patients/clients and saw the relevance and acceptability of the intervention content. The intervention development process was attentive to their real world intervention concerns. Extensive intervention tailoring to the context of each CAM discipline was found unnecessary. Participants and advisors from all CAM disciplines embraced training content, deeming it to have broad relevance and application across the three CAM disciplines. All findings informed the final intervention. CONCLUSIONS: The participatory and iterative formative research process yielded an intervention with context validity in real-world CAM practices as it: 1) is patient/client-centered, emphasizing the practitioner's role in a healing relationship; 2) is responsive to the different contexts of CAM practitioners' work and patient/client relationships; 3) integrates relevant best practices from US Public Health Service Clinical Practice Guidelines on treating tobacco dependence; and 4) is suited to the range of healing philosophies, scopes of practice and practice patterns found in participating CAM practitioners. The full CAMR study to evaluate the impact of the CAMR intervention on CAM practitioners' clinical behavior is underway.

Thermal kinetics of enzymatic time-temperature integrators (TTIs) were experimentally evaluated under both conventional and microwave heating systems in the pasteurization temperature range (50 to 90°C). Recent developments of process evaluation methodologies have Shown that standardized enzymatic time-temperature integrators (TTIs) could be successfully used for fast and correct quantification of thermal processes. Promising results have been reported for the alpha-amylase based TTI from Bacillus subtilis (BAA), which was chosen in this study as the TTI to compare the effectiveness of continuous-flow heating systems with microwave and conventional heating modes. Thermal inactivation kinetics of alpha-amylase was studied by measuring the residual activity of heat treated samples in isothermal conditions in a temperature range of 50 to 95°C and pH range, 5.0 to 6.9. Based on a first order rate of inactivation kinetics, kinetic parameters, decimal reduction time, D, and temperature sensitivity indicator, z, were calculated. (Abstract shortened by UMI.)

This thesis focused on the feasibility of substituting, partially or totally, drinking water treatment plant (DWTP) conventional pre-treatment by membrane based units, in particular by ultrafiltration (UF). For such purpose, bench and pilot scale tests with natural water were conducted, first, to address the technical feasibility and, second, to optimize its performance in order to determine whereas the proposed scheme was competitive from hydraulic and quality perspectives with the current conventional pre-treatment. Moreover, tailored microbes based tests were defined to assess its proper functioning and reliability, and additional advantages related to direct UF besides those purely related to the pre-treatment unit were investigated. The case study selected was Sant Joan Despí DWTP (Barcelona, Spain) due to its particularities: it treats Llobregat River water, which is a highly variable water resource in terms of quality and quantity, and it is a complex multistage system. As a result, this study covered a wide range of conditions and the technology under consideration could be pushed to its limits. Results showed that direct UF of raw river water was a competitive alternative to dioxichlorination, coagulation/flocculation, settling and sand filtration. The pilot plant was able to continuously treat raw river water during 2 years, independently of its quality (e.g. turbidity > 1,000 NTU), delivering water of high and stable quality, both physico-chemically and microbiologically. In terms of pre-treated water quality, most of the physico-chemical parameters monitored presented lower values and variability in the direct UF scheme than in the conventional pre-treatment process. From a microbiological perspective, the direct UF scheme tested ensured an average removal of > 5 log10 units of bacteria and viruses greater than 60 nm. The highest water yields achieved ranged between 94.0%-94.7% in optimal conditions, involving 1 or 2 chemically enhanced backwashes (CEBs) per day, transmembrane pressure (TMP) below 1 bar, filtration fluxes of 40¿70 L/(m2¿h) and low reagents consumption. When a micro-coagulation previous to the UF was applied, the increase of the hydraulic resistance during filtration was decreased and stabilized, especially in winter, the hydraulic cleaning efficiency raised and the CEB frequency diminished. Since fouling indicators (SDI15 and MFI0.45) of the direct UF permeate were lower than those associated to the conventional pre-treatment, the subsequent reverse osmosis (RO) unit would require less chemical cleanings and thus, its lifetime would be extended. In addition to this, besides the economic savings associated to the significant reduction of reagents dosed within the direct UF scheme (chemical disinfectants and coagulants mainly), a minimization of risk of RO membrane degradation was demonstrated. Studies concerning the effects on physico-chemical and transport properties of RO membranes exposed to chemicals used within the conventional pre-treatment scheme but avoided in the direct UF treatment were also undertaken. An advanced characterisation of the exposed membranes enabled understanding the RO membranes performance changes with its composition and structure modification. The implementation of direct UF would imply the pre-treatment being a single membrane filtration step. This has advantages in terms of process complexity, space requirements, as well as avoidance of chemical based disinfectants dosage. Nevertheless, the preservation of its separating properties along time is of utmost importance, especially from a microbiological standpoint. Consequently, microbes based tailored tests aiming at assessing membrane integrity were defined and conducted periodically, to determine the removal capacity reliability of the pre-treatment scheme proposed in this thesis. Results showed that membrane integrity had not been compromised despite the challenging conditions that direct UF posed.
Aquesta tesis s'ha centrat en l'estudi de la substitució, total o parcial, de l'etapa de pre-tractament d'estacions de tractament d'aigua potable (ETAPs) per processos de membrana, en particular per ultrafiltració (UF). Per a tal fi, es van realitzar experiments a nivell laboratori i pilot per, en primer lloc, avaluar la seva viabilitat tècnica, i en segon, optimitzar el seu funcionament per determinar així si l'esquema de tractament proposat era competitiu des d'un punt de vista hidràulic i de qualitat amb el pre-tractament convencional actual. A més, es van definir assajos per assegurar el seu correcte funcionament i fiabilitat, i es van identificar avantatges addicionals a les purament associades a l'etapa de pre-tractament. El cas d'estudi seleccionat va ser l'ETAP de Sant Joan Despí (Barcelona) degut a les seves particularitats: tracta aigua del riu Llobregat, que és un recurs altament variable en termes de qualitat i quantitat, i és un sistema multi-etapa complex. En conseqüència aquest estudi va cobrir un ampli rang de condicions i va permetre portar la tecnologia en qüestió a condicions límit. Els resultats vam mostrar que la UF directa d'aigua crua de riu és capaç de substituir, i resulta competitiva, amb la dioxicloració, coagulació/floculació, decantació i filtració per sorra. La planta pilot va ser capaç de tractar contínuament aigua crua durant 2 anys, independentment de la seva qualitat (ex. terbolesa d'entrada > 1000 NTU), produint aigua de qualitat alta i estable, tant fisicoquímicament com microbiològicament. La majoria dels paràmetres fisicoquímics avaluats van presentar valors inferiors i amb menor variabilitat en l'esquema d'UF directa que en el pre-tractament convencional. Des d'una perspectiva microbiològica, l'esquema d'UF directa avaluat va assegurar una eliminació > 5 log10 unitats de bactèries i virus de tamany superior a 60 nm. El rendiment hídric va oscil.lar entre 94.0-94.7% en condicions òptimes, requerint 1 o 2 contra rentats químics al dia, una pressió transmembrana per sota d'1 bar, fluxos de filtració entre 40-70 L/(m2.h) i un baix consum de reactius químics. En aplicar una micro-coagulació prèvia a la UF, l'increment de la resistència hidràulica durant la filtració va disminuir i es va estabilitzar, l'eficiència del contra rentat va augmentar, i la freqüència dels contra rentats químics va davallar. Degut a que els indicadors d'embrutiment (SDI15 i MFI0.45) del permeat d'UF directa van resultar inferiors als del pretractament convencional, és d'esperar que la unitat següent d'osmosis inversa (OI) precisi menys neteges químiques i per tant, la seva vida útil es prolongui. Addicionalment, a part de l'estalvi econòmic associat a la reducció significativa de reactius dosificats en l'esquema l'UF directa (desinfectants químics i coagulants principalment), es va demostrar una disminució del risc de degradació de les membranes d'OI. Es van dur a terme estudis avaluant els efectes de l'exposició de certs químics (dosificats en el pre-tractament convencional però no en l'UF directa) en les propietats fisicoquímiques i de transport de membranes d'OI. Una caracterització avançada va permetre relacionar els canvis de funcionament de les membranes d'OI amb els seus canvis de composició i d'estructura. La implementació de la UF directa implica que el pre-tractament consisteixi únicament en una etapa de filtració. Això suposa avantatges en termes de complexitat del procés, requeriments d'espai així com d'evitar l'ús de desinfectats químics. Tanmateix, la preservació de les seves propietats de separació al llarg del temps és de gran importància, sobretot des d'un punt de vista microbiològic. En conseqüència, es van definir i dur a terme periòdicament assajos en base a microorganismes per avaluar la integritat de la membrana d'UF directa. Els resultats van indicar que la integritat de la membrana d'UF s'havia preservat durant els 2 anys d'estudi, malgrat les condicions severes que la UF directa va suposar

This research has made an attempt to measure the efficiency and productivity scores of a large number of banks in the Gulf Cooperation Council region, over the period 1998-2014. In the main the study attempts to find out if there had been significant differences in efficiency and productivity of the banking sector in the GCC before and after the financial crisis of 2007/8. Furthermore, it has aimed to find answer to the teasing question of whether the conventional banks in the region have performed better than the Islamic banks over the entire period of the study. This study offers a novel and comprehensive approach in measuring efficiency and productivity by incorporating the so-called the resource-based view (RBV) into the main body of literature. In doing so, a number of qualitative variables has been identified to represent the intangibles for those non-substitutable, rare capabilities resources which help produce sustainable competitive edge for a firm in a given industry. Using the relevant data for a large sample of banks in the GCC, the application of Data Envelopment Analysis (DEA) has produced a number of interesting findings. At country level, Bahraini and Kuwaiti banks have turned out to be more consistently efficient over time than the banks in the other four states. Furthermore, the examination of the performance of the newly established banks has shown that they have managed to perform better than the old established ones particularly since the financial recession of 2007/8. More specifically, when Islamic and conventional banks were compared, the estimated results showed that there had been no significant differences in efficiency and productivity between the two groups of banks. Nevertheless, the Islamic banks have demonstrated to have performed better since 2007/8. On the whole, it was demonstrated that as most banks exhibited severe decline in their performance immediately after the 2007/8 recession, the majority of such banks have now managed to return to pre-2007 era and a few have even shown much greater performance since 2010/11. Finally, the study concludes that in all cases the findings have suggested that the inclusion of RBV variables has enhanced and improved the relative efficiency scores for all, and that some banks have been able to maintain consistently higher efficiency primarily due to their competitive edge and capabilities.