Shedding light on active species in Fe, Ni and Cu catalysis:photochemical, spectroscopic and electrochemical studies

Vele van de chemische omzettingen waar chemici in het laboratorium naar streven worden door de natuur vaak uitgevoerd met opmerkelijke reactiviteit en selectiviteit. In scherpe tegenstelling tot biologische systemen laten de door de mens gemaakte structurele en functionele modellen voor de biologische systemen vaak beperkte reactiviteit en selectiviteit zien als ze gebruikt worden in katalytische reacties. Het genereren van zogenaamde actieve intermediairen, de karakterisering hiervan met diverse spectroscopische technieken en het het begrijpen van hun rol in katalyse is van direct belang met betrekking tot het begrijpen van hun rol in biologische systemen. In dit proefschrift worden de synthese en karakterisering van diverse intermediairen zoals FeIV=O, FeIII-OR, FeIII-OCl, NiII-OCl and NiII-O• beschreven. Door gebruik te maken van een groot aantal technieken was het mogelijk om diverse van deze intermediairen definitief vast te stellen. Het werk dat in dit proefschrift wordt beschreven gaat met name om het verkrijgen en het spectroscopisch karakteriseren van potentiele actieve deeltjes, bestaande uit complexen van overgangsmetalen, die gevormd worden tijdens katalyse reacties. Er is uitgebreid gebruik gemaakt van elektrochemie en Raman en resonatie Raman spectroscopie om de eigenschappen van zowel een aantal ijzer en nikkel intermediairen als de interactie van koper complexen met DNA te begrijpen. Het doel was om een relatie te leggen tussen de analyse van welke deeltjes aanwezig zijn in oplossing en de katalytische activiteit

Examining commitment and heterogeneity within the membership base of agricultural co-operatives : an empirical study of a large New Zealand dairy co-operative : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Agribusiness at Massey University, New Zealand

A strong relationship between member and co-operative is vital for agricultural co-operatives. Yet most of the research on agricultural co-operatives is centered on non-relational aspects such as efficiency. Although these conventional economic centric approaches are useful in understanding co-operatives and evaluating its performance, they are not comprehensive enough. Studies on the member - co-operative relationship which require an examination of co-operatives from a socio-psychological perspective are lacking. This research gap is addressed in this thesis via first identifying three important socio-psychological phenomena in agricultural co-operatives – 1. Commitment, 2. Heterogeneity and 3. Social Capital, and presenting a conceptual framework that links the three. Thereafter, the commitment and heterogeneity sub-components of the framework were further unravelled and empirically examined by randomly surveying 2,000 members of Fonterra Co-operative Group, of which 568 responded. The organisational commitment dimension of commitment is decoupled into three components – affective (emotive), normative (ideological) and continuance (utilitarian), and the commitment to collective action dimension into two components – patronage and governance. Fonterra had moderately high levels of affective, moderate levels of normative and slightly low levels of continuance commitment. The level of commitment to collective action was moderately high as the levels of commitment to both patronage and governance were moderately high. Importantly, there was a positive association between commitment to collective action and affective and normative commitment but not continuance commitment. This suggests that it is the emotive followed by ideological aspects of membership that influence a member’s commitment to collective action, and not the utilitarian or financial benefit aspects. Heterogeneity was measured and analysed using 35 heterogeneity sources that were categorized under three dimensions – farmer-member, farm-business and member-interest. Fonterra had high levels of heterogeneity with most of the sources in all three dimensions showing high heterogeneity. Of the three dimensions, member-interest, followed by farm-business showed the greatest heterogeneity and sources within them were most likely to result in differences in affective commitment, normative commitment, continuance commitment, commitment to collective action as well as commitment to governance and patronage. In contrast, most of the sources within the farmer-member dimension were not associated with either organisational commitment or commitment to collective action

Participation technologies: a framework for the development of an online interactive GIS application

Geographic Information Systems (GIS) are generally implemented in a top-down manner and do not inherently support public participation. It is believed that when these GIS applications are supported with collaboration and decision-aid tools this gap can be reduced. This study explores the participatory tools and technologies that support spatial decision making. A step by step process is proposed to guide the selection of participation tools and technologies in different scenarios. An online application prototype is then developed with the tools suggested by the step by step process to support public participation in the Ames Urban Fringe Plan in Story County, Iowa. The application is evaluated for its effectiveness based on the survey feedback received from the participants and interview responses. Opportunities, challenges and future recommendations are presented

The determination of the heat transfer film coefficients of internally heated and twisted strips

As the demand for power supply is increasing, the power from nuclear fission is assuming an important role in the field of power production. The enormous quantity of heat generated during the fission process can be utilized for the generation of power. To get maximum advantage out of the fission process, the fission material must be fabricated into a unit of proper shape to permit the control of the process and safe removal of heat generated. This unit, composed of fuel elements is known as the reactor core and is one of the major concerns in nuclear power development. The shape of the fuel element has considerable effect on the amount of heat transferred from the fuel elements. Since the amount of heat generated in the fuel element is in the order 5 x 105 B/hr. ft2, it is necessary that the fuel elements are designed to give maximum possible heat transfer coefficients. The achievement of higher heat transfer coefficients is not a problem solely associated with reactor cores. This is the aim of any designer of a heat exchange apparatus. Higher heat transfer coefficients can be achieved by increasing turbulence over the heat transfer surface. The turbulence can be promoted by an increase in the coolant velocity or by interrupting the flow by shaped objects in the path of flow. Higher heat transfer coefficients can be achieved for interrupted surfaces with low coolant flow rates with a reasonable increase in the pumping power. The use of twisted plates as interrupters will create a swirling motion in the fluid. The swirling motion is expected to promote higher heat transfer rates. This investigation is aimed at; 1) the design and construction of an apparatus for the determination of heat transfer coefficients by using an induction heater to generate heat in the test section, 2) the comparison of the results with data available and 3) the evaluation of the effect of a twisted plate on the heat transfer coefficients --Introduction, pages 7-8

Vacancy-mediated mechanism of nitrogen substitution in carbon nanotubes

Nitrogen substitution reaction in a graphene sheet and carbon nanotubes of different diameter are investigated using the generalized tight-binding molecular dynamics method. The formation of a vacancy in curved graphene sheet or a carbon nanotube is found to cause a curvature dependent local reconstruction of the surface. Our simulations and analysis show that vacancy mediated N substitution (rather than N chemisorption) is favored on the surface of nanotubes with diameter larger than 8 nm. This predicted value of the critical minimum diameter for N incorporation is confirmed by experimental results presented on nitrogen-doped multiwalled nanotubes with [approximate]5 at. % nitrogen prepared by the thermal chemical vapor deposition process