Metallocene ethylene-1-octene copolymers:influence of comonomer content on thermo-mechanical, rheological, and thermo-oxidative behaviours before and after melt processing in an internal mixer

The influence of the comonomer content in a series of metallocene-based ethylene-1-octene copolymers (m-LLDPE) on thermo-mechanical, rheological, and thermo-oxidative behaviours during melt processing were examined using a range of characterisation techniques. The amount of branching was calculated from 13C NMR and studies using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were employed to determine the effect of short chain branching (SCB, comonomer content) on thermal and mechanical characteristics of the polymer. The effect of melt processing at different temperatures on the thermo-oxidative behaviour of the polymers was investigated by examining the changes in rheological properties, using both melt flow and capillary rheometry, and the evolution of oxidation products during processing using infrared spectroscopy. The results show that the comonomer content and catalyst type greatly affect thermal, mechanical and oxidative behaviour of the polymers. For the metallocene polymer series, it was shown from both DSC and DMA that (i) crystallinity and melting temperatures decreased linearly with comonomer content, (ii) the intensity of the ß-transition increased, and (iii) the position of the tan δmax peak corresponding to the a-transition shifted to lower temperatures, with higher comonomer content. In contrast, a corresponding Ziegler polymer containing the same level of SCB as in one of the m-LLDPE polymers, showed different characteristics due to its more heterogeneous nature: higher elongational viscosity, and a double melting peak with broader intensity that occurred at higher temperature (from DSC endotherm) indicating a much broader short chain branch distribution. The thermo-oxidative behaviour of the polymers after melt processing was similarly influenced by the comonomer content. Rheological characteristics and changes in concentrations of carbonyl and the different unsaturated groups, particularly vinyl, vinylidene and trans-vinylene, during processing of m-LLDPE polymers, showed that polymers with lower levels of SCB gave rise to predominantly crosslinking reactions at all processing temperatures. By contrast, chain scission reactions at higher processing temperatures became more favoured in the higher comonomer-containing polymers. Compared to its metallocene analogue, the Ziegler polymer showed a much higher degree of crosslinking at all temperatures because of the high levels of vinyl unsaturation initially present.

L'orientation et la propriété de mémoire de forme des polymères cristallins liquides à chaînes latérales covalents et supramoléculaires

In many studies of the side-chain liquid crystalline polymers (SCLCPs) bearing azobenzene mesogens as pendant groups, obtaining the orientation of azobenzene mesogens at a macroscopic scale as well as its control is important, because it impacts many properties related to the cooperative motion characteristic of liquid crystals and the trans-cis photoisomerization of the azobenzene molecules. Various means can be used to align the mesogens in the polymers, including rubbed surface, mechanical stretching or shearing, and electric or magnetic field. In the case of azobenzene-containing SCLCPs, another method consists in using linearly polarized light (LPL) to induce orientation of azobenzene mesogens perpendicular to the polarization direction of the excitation light, and such photoinduced orientation has been the subject of numerous studies. In the first study realized in this thesis (Chapter 1), we carried out the first systematic investigation on the interplay of the mechanically and optically induced orientation of azobenzene mesogens as well as the effect of thermal annealing in a SCLCP and a diblock copolymer comprising two SCLCPs bearing azobenzene and biphenyl mesogens, respectively. Using a supporting-film approach previously developed by our group, a given polymer film can be first stretched in either the nematic or smectic phase to yield orientation of azobenzene mesogens either parallel or perpendicular to the strain direction, then exposed to unpolarized UV light to erase the mechanically induced orientation upon the trans–cis isomerization, followed by linearly polarized visible light for photoinduced reorientation as a result of the cis–trans backisomerization, and finally heated to different LC phases for thermal annealing. Using infrared dichroism to monitor the change in orientation degree, the results of this study have unveiled complex and different orientational behavior and coupling effects for the homopolymer of poly{6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} (PAzMA) and the diblock copolymer of PAzMA-block- poly{6-[4-(4-cyanophenyl) phenoxy]hexyl methacrylate} (PAzMA-PBiPh). Most notably for the homopolymer, the stretching-induced orientation exerts no memory effect on the photoinduced reorientation, the direction of which is determined by the polarization of the visible light regardless of the mechanically induced orientation direction in the stretched film. Moreover, subsequent thermal annealing in the nematic phase leads to parallel orientation independently of the initial mechanically or photoinduced orientation direction. By contrast, the diblock copolymer displays a strong orientation memory effect. Regardless of the condition used, either for photoinduced reorientation or thermal annealing in the liquid crystalline phase, only the initial stretching-induced perpendicular orientation of azobenzene mesogens can be recovered. The reported findings provide new insight into the different orientation mechanisms, and help understand the important issue of orientation induction and control in azobenzene-containing SCLCPs. The second study presented in this thesis (Chapter 2) deals with supramolecular side-chain liquid crystalline polymers (S-SCLCPs), in which side-group mesogens are linked to the chain backbone through non-covalent interactions such as hydrogen bonding. Little is known about the mechanically induced orientation of mesogens in S-SCLCPs. In contrast to covalent SCLCPs, free-standing, solution-cast thin films of a S-SCLCP, built up with 4-(4’-heptylphenyl) azophenol (7PAP) H-bonded to poly(4-vinyl pyridine) (P4VP), display excellent stretchability. Taking advantage of this finding, we investigated the stretching-induced orientation and the viscoelastic behavior of this S-SCLCP, and the results revealed major differences between supramolecular and covalent SCLCPs. For covalent SCLCPs, the strong coupling between chain backbone and side-group mesogens means that the two constituents can mutually influence each other; the lack of chain entanglements is a manifestation of this coupling effect, which accounts for the difficulty in obtaining freestanding and mechanically stretchable films. Upon elongation of a covalent SCLCP film cast on a supporting film, the mechanical force acts on the coupled polymer backbone and mesogenic side groups, and the latter orients cooperatively and efficiently (high orientation degree), which, in turn, imposes an anisotropic conformation of the chain backbone (low orientation degree). In the case of the S-SCLCP of P4VP-7PAP, the coupling between the side-group mesogens and the chain backbone is much weakened owing to the dynamic dissociation/association of the H-bonds linking the two constituents. The consequence of this decoupling is readily observable from the viscoelastic behavior. The average molecular weight between entanglements is basically unchanged in both the smectic and isotropic phase, and is similar to non-liquid crystalline samples. As a result, the S-SCLCP can easily form freestanding and stretchable films. Furthermore, the stretching induced orientation behavior of P4VP-7PAP is totally different. Stretching in the smectic phase results in a very low degree of orientation of the side-group mesogens even at a large strain (500%), while the orientation of the main chain backbone develops steadily with increasing the strain, much the same way as amorphous polymers. The results imply that upon stretching, the mechanical force is mostly coupled to the polymer backbone and leads to its orientation, while the main chain orientation exerts little effect on orienting the H-bonded mesogenic side groups. This surprising finding is explained by the likelihood that during stretching in the smectic phase (at relatively higher temperatures) the dynamic dissociation of the H-bonds allow the side-group mesogens to be decoupled from the chain backbone and relax quickly. In the third project (Chapter 3), we investigated the shape memory properties of a S-SCLCP prepared by tethering two azobenzene mesogens, namely, 7PAP and 4-(4'-ethoxyphenyl) azophenol (2OPAP), to P4VP through H-bonding. The results revealed that, despite the dynamic nature of the linking H-bonds, the supramolecular SCLCP behaves similarly to covalent SCLCP by exhibiting a two-stage thermally triggered shape recovery process governed by both the glass transition and the LC-isotropic phase transition. The ability for the supramolecular SCLCP to store part of the strain energy above T[subscript g] in the LC phase enables the triple-shape memory property. Moreover, thanks to the azobenzene mesogens used, which can undergo trans-cis photoisomerization, exposure the supramolecular SCLCP to UV light can also trigger the shape recovery process, thus enabling the remote activation and the spatiotemporal control of the shape memory. By measuring the generated contractile force and its removal upon turning on and off the UV light, respectively, on an elongated film under constant strain, it seems that the optically triggered shape recovery stems from a combination of a photothermal effect and an effect of photoplasticization or of an order-disorder phase transition resulting from the trans-cis photoisomerization of azobenzene mesogens.

Fluorescent antibody test, quantitative polymerase chain reaction pattern and clinical aspects of rabies virus strains isolated from main reservoirs in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Investigating relationships between relationship quality, customer loyalty and cooperation : an empirical study of convenience stores' franchise chain systems in Taiwan

Franchising has been widely accepted as an effective way to conduct and expand businesses. However, a franchise system is not a guarantee of success in the market. A successful franchise system should rely on a close and strong franchising relationship. Franchising is an important relationship management business. Franchising arrangements normally last for a number of years, so the franchisor and franchisee in the arrangement relationship are usually motivated to cooperate with each other. In addition, highly loyal franchisees may be obtained through a successful long-term franchising relationship. Over the last few decades, there has been a tremendous wave of interest in franchising relationships. However, little research has been conducted to determine the reasons for long-term franchising relationships. As a result, this study focuses on the important elements that might lead to a successful long-term franchising relationship. This study attempts to examine empirically three essential constructs (relationship quality, cooperation and customer loyalty), which might lead to successful long-term franchising relationships between franchisees and franchisors among the convenience stores in Taiwan. Mailed questionnaires were utilised to collect the research data. A total of 500 surveys were mailed randomly to the manager/supervisor of convenience stores’ franchisees among the four main franchisors (7-ELEVEN, Family, Hi-Life and OK) in Taiwan. The final sample size is 120, yielding a response rate of 24 per cent. The results show that relationship quality positively influences the cooperative relationships between franchisors and franchisees. Relationship quality is also positively correlated with franchisees’ loyalty. Additionally, the results indicate that the cooperative relationships between franchisors and franchisees are significantly associated with franchisees’ loyalty.

Supply chain collaboration : capabilities for continuous innovation

Purpose – The purpose of this study is to investigate how collaborative relationships enhance continuous innovation in the supply chain using case studies. Design/methodology/approach – The data were collected from semi-structured interviews with 23 managers in ten case studies. The main intention was to comprehend how these firms engaged in collaborative relationships and their importance for successful innovation. The study adopted a qualitative approach to investigating these factors. Findings – The findings demonstrate how differing relationships can impact on the operation of firms and their capacities to innovate. The ability to work together with partners has enabled firms to integrate and link operations for increased effectiveness as well as embark on both radical and incremental innovation. Research limitations/implications – The research into the initiatives and strategies for collaboration was essentially exploratory. A qualitative approach using case studies acknowledged that the responses from managers were difficult to quantify or gauge the extent of these factors. Practical implications – The findings have shown various methods where firms integrated with customers and suppliers in the supply chain. This was evident in the views of managers across all the firms examined, supporting the importance of collaboration and efficient allocation of resources throughout the supply chain. They were able to set procedures in their dealings with partners, sharing knowledge and processes, and subsequently joint-planning and investing with them for better operations, systems and processes in the supply chain. Originality/value – The case studies serve as examples for managers in logistics organisation who are contemplating strategies and issues on collaborative relationships. The study provides important lessons on how such relationships can impact on the operation of firms and their capability to innovate. Keywords Supply chain management, Innovation, Relationship marketing

The domestic kitchen : the weak link in the food chain : is convenience leading to apathy?

To investigate the meaning and understanding of domestic food preparation within the lived experience of the household's main food preparer this ethnographic study used a combination of qualitative and quantitative methodologies. Data were collected from three sources: the literature; an in-store survey of251 food shoppers chosen at random while shopping during both peak and off peak shopping periods at metropolitan supermarkets; and semi-structured interviews with the principal food shopper and food preparer of 15 different Brisbane households. Male and female respondents representing a cross section of socio-economic groupings, ranged in age from 19-79 years and were all from English speaking backgrounds. Changes in paid labour force participation, income and education have increased the value of the respondents' time, instigating massive changes in the way they shop, cook and eat. Much of their food preparation has moved from the domestic kitchen into the kitchens of other food establishments. For both sexes, the dominant motivating force behind these changes is a combination of the their self perceived lack of culinary skill; lack of enjoyment of cooking and lack of motivation to cook. The females in paid employment emphasise all factors, particularly the latter two, significantly more than the non-employed females. All factors are of increasing importance for individuals aged less than 35 years and conversely, of significantly diminished importance to older respondents. Overall, it is the respondents aged less than 25 years who indicate the lowest cooking frequency and/or least cooking ability. Inherent in this latter group is an indifference to the art/practice of preparing food. Increasingly, all respondents want to do less cooking and/or get the cooking over with as quickly as possible. Convenience is a powerful lure by which to spend less time in the kitchen. As well, there is an apparent willingness to pay a premium for convenience. Because children today are increasingly unlikely to be taught to cook, addressing the food skills deficit and encouraging individuals to cook for themselves are significant issues confronting health educators. These issues are suggested as appropriate subjects of future research.

Relationship management as a strategy for supply chain engagement in the civil engineering construction industry

Many studies into construction procurement methods reveal evidence of a need to change the culture and attitude in the construction industry, transition from traditional adversarial relationships to cooperative and collaborative relationships. At the same time there is also increasing concern and discussion on alternative procurement methods, involving a movement away from traditional procurement systems. Relational contracting approaches, such as partnering and relationship management, are business strategies that align the objectives of clients, commercial participants and stakeholders. It provides a collaborative environment and a framework for all participants to adapt their behaviour to project objectives and allows for engagement of those subcontractors and suppliers down the supply chain. The efficacy of relationship management in the client and contractor groups is proven and well documented. However, the industry has a history of slow implementation of relational contracting down the supply chain. Furthermore, there exists little research on relationship management conducted in the supply chain context. This research aims to explore the association between relational contracting structures and processes and supply chain sustainability in the civil engineering construction industry. It endeavours to shed light on the practices and prerequisites for relationship management implementation success and for supply sustainability to develop. The research methodology is a triangulated approach based on Cheung.s (2006) earlier research where questionnaire survey, interviews and case studies were conducted. This new research includes a face-to-face questionnaire survey that was carried out with 100 professionals from 27 contracting organisations in Queensland from June 2008 to January 2009. A follow-up survey sub-questionnaire, further examining project participants. perspectives was sent to another group of professionals (as identified in the main questionnaire survey). Statistical analysis including multiple regression, correlation, principal component factor analysis and analysis of variance were used to identify the underlying dimensions and test the relationships among variables. Interviews and case studies were conducted to assist in providing a deeper understanding as well as explaining findings of the quantitative study. The qualitative approaches also gave the opportunity to critique and validate the research findings. This research presents the implementation of relationship management from the contractor.s perspective. Findings show that the adaption of relational contracting approach in the supply chain is found to be limited; contractors still prefer to keep the suppliers and subcontractors at arm.s length. This research shows that the degree of match and mismatch between organisational structuring and organisational process has an impact on staff.s commitment level and performance effectiveness. Key issues affecting performance effectiveness and relationship effectiveness include total influence between parties, access to information, personal acquaintance, communication process, risk identification, timely problem solving and commercial framework. Findings also indicate that alliance and Early Contractor Involvement (ECI) projects achieve higher performance effectiveness at both short-term and long-term levels compared to projects with either no or partial relationship management adopted.

Investigating relationships between relationship quality, customer loyalty and cooperation : an empirical study of convenience stores' franchise chain systems

Franchising has become a way to minimise the risks of small business management. There has been little research into the factors that promote franchise relationship success. This study attempts to empirically examine the important elements (relationship quality, customer loyalty and cooperation), which might promote a successful long-term franchising relationship between franchisors and franchisees within the context of convenience stores in Taiwan. A model of these relationships was developed and tested. A total of 500 surveys were mailed to a random sample of convenience stores’ franchisee owners among the four main franchisors in Taiwan. The results show that relationship quality positively influences the cooperation between franchisors and franchisees and is positively correlated with franchisee loyalty. Additionally, the cooperative behaviour between franchisees and franchisors is significantly associated with franchisees’ loyalty.

A test rig for the condition-based maintenance application on the traction chain of very high speed trains

The preventive maintenance of traction equipment for Very High Speed Trains (VHST) nowadays is becoming very expensive owing to the high complexity and quality of these components that require high reliability. An efficient maintenance approach like the Condition-Based Maintenance (CBM) should be implemented to reduce the costs. For this purpose, an experimental full-scale test rig for the CBM of VHST traction equipment has been designed to investigate in detail failures in the main mechanical components of system, i.e. motor, bearings and gearbox. The paper describes the main characteristics of this unique test rig, able to reproduce accurately the train operating conditions, including the relative movements of the motor, the gearbox and the wheel axle. Gearbox, bearing seats and motor are equipped by accelerometers, thermocouples, torque meter and other sensors in different positions. The testing results give important information about the most suitable sensor position and type to be installed for each component and show the effectiveness of the techniques used for the signal analysis in order to identify faults of the gearbox and motor bearings.

The use of supply chain management to reduce delays as result of pre-construction deficiencies in Malaysian public sector construction projects

This thesis examined the delay causes of Malaysian public sector projects. Using a systematic approach, the researcher identified the main delay factors and categorised them into pathogens. The pathogens were matched with beneficial Supply Chain Management (SCM) tools and developed into a holistic SCM framework to facilitate improvements in Malaysian public sector projects. The researcher concluded that SCM is the potential saviour for the delay dilemma and that it is necessary for the Malaysian government to initiate the revolutionary practice.

Compliance with seafood safety standards within the Vietnamese finfish capture distribution chain

This thesis examined the level of food safety compliance with government regulations and investigated routes of microbiological contaminations in raw finfish within Vietnamese domestic seafood distribution chains. Findings from direct observation, microbiological analysis and employee surveys were synthesized to identify the main factors affecting food safety and hygiene practices of fish distributors. The studies produced clear recommendations for food safety management in the domestic distribution chains. The findings may contribute to national efforts to decrease the risks of fish-borne illness for consumers in Vietnam.

Distribution and adhesion-promoting activity of alpha4 and alpha5 chain laminins in human endothelia and carcinomas

Basement membranes are specialized sheets of extracellular matrix found in contact with epithelia, endothelia, and certain isolated cells. They support tissue architecture and regulate cell behaviour. Laminins are among the main constituents of basement membranes. Due to differences between laminin isoforms, laminins confer structural and functional diversity to basement membranes. The first aim of this study was to gain insights into the potential functions of the then least characterized laminins, alpha4 chain laminins, by evaluating their distribution in human tissues. We thus created a monoclonal antibody specific for laminin alpha4 chain. By immunohistochemistry, alpha4 chain laminins were primarily localized to basement membranes of blood vessel endothelia, skeletal, heart, and smooth muscle cells, nerves, and adipocytes. In addition, alpha4 chain laminins were found in the region of certain epithelial basement membranes in the epidermis, salivary gland, pancreas, esophagus, stomach, intestine, and kidney. Because of the consistent presence of alpha4 chain laminins in endothelial basement membranes of blood vessels, we evaluated the potential roles of endothelial laminins in blood vessels, lymphatic vessels, and carcinomas. Human endothelial cells produced alpha4 and alpha5 chain laminins. In quantitative and morphological adhesion assays, human endothelial cells barely adhered to alpha4 chain-containing laminin-411. The weak interaction of endothelial cells with laminin-411 appeared to be mediated by alpha6beta1 integrin. The alpha5 chain-containing laminin-511 promoted endothelial cell adhesion better than laminin-411, but it did not promote the formation of cell-extracellular matrix adhesion complexes. The adhesion of endothelial cells to laminin-511 appeared to be mediated by Lutheran glycoprotein together with beta1 and alphavbeta3 integrins. The results suggest that these laminins may induce a migratory phenotype in endothelial cells. In lymphatic capillaries, endothelial basement membranes showed immunoreactivity for laminin alpha4, beta1, beta2, and gamma1 chains, type IV and XVIII collagens, and nidogen-1. Considering the assumed inability of alpha4 chain laminins to polymerize and to promote basement membrane assembly, the findings may in part explain the incomplete basement membrane formation in these vessels. Lymphatic capillaries of ovarian carcinomas showed immunoreactivity also for laminin alpha5 chain and its receptor Lutheran glycoprotein, emphasizing a difference between normal and ovarian carcinoma lymphatic capillaries. In renal cell carcinomas, immunoreactivity for laminin alpha4 chain was found in stroma and basement membranes of blood vessels. In most tumours, immunoreactivity for laminin alpha4 chain was also observed in the basement membrane region of tumour cell islets. Renal carcinoma cells produced alpha4 chain laminins. Laminin-411 did not promote adhesion of renal carcinoma cells, but inhibited their adhesion to fibronectin. Renal carcinoma cells migrated more on laminin-411 than on fibronectin. The results suggest that alpha4 chain laminins have a counteradhesive function, and may thus have a role in detachment and invasion of renal carcinoma cells.

Information, risk and trust in the food chain : Ex-ante valuation of consumer willingness to pay for beef quality information using the contingent valuation method

The safety of food has become an increasingly interesting issue to consumers and the media. It has also become a source of concern, as the amount of information on the risks related to food safety continues to expand. Today, risk and safety are permanent elements within the concept of food quality. Safety, in particular, is the attribute that consumers find very difficult to assess. The literature in this study consists of three main themes: traceability; consumer behaviour related to both quality and safety issues and perception of risk; and valuation methods. The empirical scope of the study was restricted to beef, because the beef labelling system enables reliable tracing of the origin of beef, as well as attributes related to safety, environmental friendliness and animal welfare. The purpose of this study was to examine what kind of information flows are required to ensure quality and safety in the food chain for beef, and who should produce that information. Studying the willingness to pay of consumers makes it possible to determine whether the consumers consider the quantity of information available on the safety and quality of beef sufficient. One of the main findings of this study was that the majority of Finnish consumers (73%) regard increased quality information as beneficial. These benefits were assessed using the contingent valuation method. The results showed that those who were willing to pay for increased information on the quality and safety of beef would accept an average price increase of 24% per kilogram. The results showed that certain risk factors impact consumer willingness to pay. If the respondents considered genetic modification of food or foodborne zoonotic diseases as harmful or extremely harmful risk factors in food, they were more likely to be willing to pay for quality information. The results produced by the models thus confirmed the premise that certain food-related risks affect willingness to pay for beef quality information. The results also showed that safety-related quality cues are significant to the consumers. In the first place, the consumers would like to receive information on the control of zoonotic diseases that are contagious to humans. Similarly, other process-control related information ranked high among the top responses. Information on any potential genetic modification was also considered important, even though genetic modification was not regarded as a high risk factor.