21 resultados para Structural development

em Aston University Research Archive


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Uniform thin-films of polymer blends can be produced through spin-coating, which is used on an industrial scale for the production of light emitting diodes, and more recently organic photovoltaic devices. Here, we present the results of the direct observation, and control, over the phase separation of polystyrene and poly(9,9′-dioctylfluorene) during spin-coating using high speed stroboscopic fluorescence microscopy. This new approach, imaging the fluorescence, from a blend of fluorescent + non-fluorescent polymers allows for intensity to be directly mapped to composition, providing a direct determination of composition fluctuations during the spin-coating process. We have studied the compositional development and corresponding structural development for a range of compositions, which produce a range of different phase separated morphologies. We initially observe domains formed by spinodal decomposition, coarsening via Ostwald Ripening until an interfacial instability causes break-up of the bicontinuous morphology. Ostwald ripening continues, and depending upon composition a bicontinuous morphology is re-established. By observing compositional and morphological development in real-time, we are able to direct and control morphological structure development through control of the spin coating parameters via in situ feedback. © 2013 The Royal Society of Chemistry.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Poverty alleviation and social upliftment of rural India is closely linked with the availability and use of energy for development. At the same time, sustainable supply of clean and affordable renewable energy sources is required if development is to be sustainable, so that it does not cause any environmental problems. The purpose of this paper is to determine the key variables of renewable energy implementation for sustainable development, on which the top management should focus. In this paper, an interpretive structural modeling (ISM) - based approach has been employed to model the implementation variables of renewable energy for sustainable development. These variables have been categorized under ‘enablers’ that help to increase the implementation of renewable energy for sustainable development. A major finding of this research is that public awareness regarding renewable energy for sustainable development is a very significant enabler. In this paper, an interpretation of variables of renewable energy for sustainable development in terms of their driving and dependence powers has been examined. For better results, top management should focus on improving the high-driving power enablers such as leadership, strategic planning, public awareness, top management support, availability of finance, government support, and support from interest groups.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Picking up on one of Hymer's key contributions, this paper examines the impact that inward foreign direct investment (FDI) into the UK has on the patterns of development, both within and across regions. Using a panel of data for the manufacturing sector, the paper illustrates that even where one isolates the effect on the domestic sector alone, inward investment acts to increase the demand for skilled, relative to unskilled labour, and also generates the expected agglomeration effects in terms of the demand for capital investment. The paper then goes on to draw certain policy comparisons between these findings and the desired aim of attracting FDI, notably to increase demand for labour in those regions suffering structural unemployment, and secondly to reduce the disparities between regions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objectives: The study of aggression and anger in competitive sport relies on accurate and economical measurement via observation, interview and questionnaire. Unfortunately, extant questionnaires have been criticised for having poor validity, are not sport specific, or reflect mood states rather than trait qualities. Therefore, a measure of trait anger and aggressiveness in competitive athletes was developed. Method: A list of statements representing aggressiveness and anger was generated and distributed to competitive athletes from diverse sports. Exploratory and confirmatory analyses were used to verify the theoretically predicted factor structure. Correlations with an extant measure of aggression and anger were used to ascertain concurrent validity. Discriminant validity was tested by comparing males with females, and aggressive with non-aggressive footballers. Results: A 12-item scale (Competitive Aggressiveness and Anger Scale, CAAS) consisting of two subscales was derived using principal component factor analysis with oblimin rotation. Confirmatory factor analysis using structural equation modelling confirmed the overall structure. Test-retest correlation, construct and discriminant validities were good, supporting the utility of the scale as a measure of athlete trait aggressiveness and anger. Conclusions: The CAAS appears to be a useful measure of athletic anger and aggressiveness. Its brevity and ability to discriminate aggressive from non-aggressive athletes should prove useful for future research concerning aggressive behaviour in competitive athletes. © 2006 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Using panel data for 41 developed and developing countries over the period 1998-2004, this paper examines the links between ICT diffusion and human development. We conducted a panel regression analysis of the investments in healthcare, education and information and communication technology (ICT) against human development index (HDI). The results show that these variables can be used to predict HDI scores. In agreement with findings of previous research, it is clear from our analysis that the central focus on ICT as a solution for development will not bring the results that the promoters of ICT as an ‘engine of growth’ are expecting. It is unwise to disaggregate the issues of education and healthcare infrastructure from ICT infrastructure development. ICT policies should be integrated with other national policies in order to find a holistic and structural solution to development.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The introduction of Regional Development Agencies (RDAs) in the English regions in 1999 presented a new set of collaborative challenges to existing local institutions. The key objectives of the new policy impetus emphasise increased joined-up thinking and holistic regional governance. Partners were enjoined to promote cross-sector collaboration and present a coherent regional voice. This study aims to evaluate the impact of an RDA on the partnership infrastructure of the West Midlands. The RDA network incorporates a wide spectrum of interest and organisations with diverse collaborative histories, competencies and capacities. The study has followed partners through the process over an eighteen-month period and has sought to explore the complexities and tensions of partnership working 'on the ground'. A strong qualitative methodology has been employed in generating 'thick descriptions' of the policy domain. The research has probed beyond the 'rhetoric' of partnerships and explores the sensitivities of the collaboration process. A number of theoretical frameworks have been employed, including policy network theory; partnership and collaboration theory; organisational learning; and trust and social capital. The structural components of the West Midlands RDA network are explored, including the structural configuration of the network and stocks of human and social capital assets. These combine to form the asset base of the network. Three sets of network behaviours are then explored, namely, strategy, the management of perceptions, and learning. The thesis explores how the combination of assets and behaviours affect, and in turn are affected by, each other. The findings contribute to the growing body of knowledge and understanding surrounding policy networks and collaborative governance.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The study examined the relationships between antecedents, timeliness in NPD and INPR, and consequences. A conceptual framework was tested using 232 new products from South Korean firms. The hypothesized relationships among the constructs in the model were evaluated by multiple regression and hierarchal regression analyses using SPSS 12 as well as by structural equation modelling (SEM) using SIMPLIS LISREL. In addition, confirmatory factor analysis (CFA) was carried out using SIMPLIS LISREL. In the direct relationships, cross-functional linkages and marketing synergy exhibited a statistically significant effect on NPD timeliness. The results also supported the influences of the HQ-subsidiary/agent relationship and NPD timeliness on INPR timeliness as well as INPR timeliness on performance. In the mediating effect tests, marketing proficiency significantly accounts for the relationships between cross-functional linkages and NPD timeliness, between marketing synergy and NPD timeliness, and between the HQ-subsidiary/agent relationship and INPR timeliness. Technical proficiency also mediates the effect of the HQ-subsidiary/agent relationship on INPR timeliness. The influence of NPD timeliness on new product performance in target markets is attributed to INPR timeliness. As for the results of the external environmentals and standardization influences, competitive intensity moderates the relationship between NPD timeliness and new product performance. Technology change also moderates the relationship between cross-functional linkages and NPD timeliness and between timeliness in NPD and INPR and performance. Standardization has a moderating role on the relationship between NPD timeliness and INPR timeliness. This study presents the answers to research questions which concern what factors are predictors of criterion variables, how antecedents influence timeliness in NPD and INPR and when the direct relationships in the INPR process are strengthened.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This study was concerned with the structure, functions and development, especially the performance, of some rural small firms associated with the Council for Small Industries in Rural Areas (C?SIRA) of England. Forty firms were used as the main basis of analysis. For some aspects of the investigation, however, data from another 54 firms, obtained indirectly through nine CoSIRA Organisers, were also used. For performance-analysis, the 40 firms were firstly ranked according to their growth and profitability rates which were calculated from their financial data. Then each of the variables hypothesised to be related to performance was tested to ascertain its relationship with performance, using the Spearman's Rank Correlation technique. The analysis indicated that each of the four factors .. the principal, the firm itself, its management, and the environment - had a bearing upon the performance of the firm. Within the first factor, the owner-manager's background and attitudes were found to be most important; in the second, the firm's size, age and scope of activities were also found to be correlated with performance; with respect to the third, it was revealed that firms which practised some forms of systems in planning, control and costing performed better than those which did not and, finally with respect to the fourth factor, it was found that some of the services provided by CoSIRA, especially credit finance, were facilitative to the firm's performance. Another significant facet of the firms highlighted by the study was their multifarious roles. These, meeting economic, psychological, sociological and political needs, were considered to be most useful to man and his society. Finally, the study has added light to the structural characteristics of the sampled firms, including various aspects of their development, orientation and organisation, as well as their various structural strengths and weakness. ' .

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The investigation of renal pathophysiology and toxicology has traditionally been advanced by the development of increasingly defined and refined in vitro preparations. This study has sought to develop and evaluate various methods of producing pure samples of renal proximal tubules (PTs) from the Fischer rat. The introduction summarised the most common in vitro preparations together with the parameters used to monitor viability - particularly with regard to toxic events. The most prevalent isolation methods have involved the use of collagenase to produce dissociation of the cortex. However, the present study has shown that even the mildest collagenase treatment caused significant structural damage which resulted in a longevity of only 3hr in suspension. An alternative mechanical isolation technique has been developed in this study that consists of perfusion loading the renal glomeruli with Fe304 followed by disruption of the cortex by homogenisation and sequential sieving. The glomeruli are removed magnetically and the PTs then harvested by a 64μM sieve. PTs isolated in this way showed a vastly superior structural preservation over their collagenase isolated counterparts; also oxygen consumption and enzyme leakage measurements showed a longevity in excess of 6hr when incubated in a very basic medium. Attempts were then made to measure the cytosolic calcium levels in both mechanical and collagenase isolated PTs using the fluorescent calcium indicator Fura. However results were inconclusive due to significant binding of the Fura to the external PT surfaces. In conclusion, PTs prepared by the present mechanical isolation technique exhibit superior preservation and longevity compared with even the mildest collagenase isolation technique and hence appear to offer potential advantages over collagenase isolation as an in vitro renal system.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The aim of this research is to promote the use of G.R.P. as a structural material. In the past, the use of G.R.P. has been confined to non-load carrying applications. Such uses are still rapidly increasing but in addition significant changes have been made during the last decade in the development of semi-structural and now even fully structural applications. Glass-reinforced plastic is characterized by a high strength but a relatively low modulus of elasticity. For this reasona G.R.P. structure can expect to show large deformations as a result of which the individual structural members will fail under load due to a loss of stability rather than approaching the ultimate strength of the material. For this reason the selection of the geometrical shapes of G.R.P. structural elements is considered to be an important factor in designing G.R.P. structures. The first chapter of this thesis deals with a general review of the theoretical and experimental methods used to describe the structural properties of G.R.P. The research programme includes five stages dealing with the structural behaviour of G.R.P. The first stage (Chapter 2) begins with selecting and designing an optimum box beam cross-section which gives the maximum flexural and torsional rigidity. The second stage of investigation (Chapter 3) deals with beam to beam connections. A joint was designed and manufactured with different types of fasteners used to connect two beam units. A suitable fastener was selected and the research extended to cover the behaviour of long span beams using multiple joints. The third part of the investigation includes a study of the behaviour of box beams subjected to combined bending, shear and torsion. A special torque rig was developed to perform the tests. Creep deformation of 6 m span G.R.P. was investigated as the fourth stage under a range of loading conditions. As a result of the phenomenon of post buckling behaviour exhibited in the compression flange during testing of box beams during earlier stages of the investigation it was decided to consider this phenomenon in more detail in the final stage of the investigation. G.R.P. plates with different fibre orientation were subjected to uniaxial compression and tested up to failure. In all stages of the investigation theoretical predictions and experimental results were compared and generally good correlation between theory and experimental data was observed.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The research work described in this thesis is concerned with the development of glassfibre reinforced plastics for structural uses in Civil Engineering construction. The first stage was primarily concerned with the design of GRP lamintes with structura1 properties and method of manufacture suitable for use with relatively large structural components. A cold setting, pressure moulding technique was developed which proved to be efficient in reducing the void content in the composite and minimising the exothermic effect due to curing. The effect of fibre content and fibre arrangement on strength and stiffness of the cornposite was studied and the maximum amount of' fibre content that could be reached by the adopted type of moulding technique was determined. The second stage of the project was concerned with the introduction of steel-wire "sheets" into the GRP cornposites, to take advantage of the high modulus of steel wire to improve the GRP stiffness and to reduce deformation. The experimental observations agreed reasonably well with theoretical predictions in both first and second stages of the work. The third stage was concerned with studying the stability of GRP flat rectangular plates subjected to uniaxial compression or pure shear, to simulate compression flanges or shear webs respectively. The investigation was concentrated on the effect of fibre arrangement in the plate on buckling load. The effect of the introduction of steel-wire sheets on the plate stability in compression was also investigated. The boundary conditions were chosen to be close to those usually assumed in built-up box-sections for both compression flanges and webs. The orthotropic plate and the mid-plane symmetric were used successfully in predicting the buckling load theoretically. In determining the buckling load experimentally, two methods were used. The Southwell plot method and electrical strain gauge method. The latter proved to be more reliable in predicting the buckling load than the former, especially for plates under uniaxial compression. Sample design charts for GRP plates that yield and buckle simultaneously under compression are also presented in the thesis. The final stage of the work dealt with the design and test of GRP beams. The investigation began by finding the optimum cross-section for a GRP beam. The cross-section which was developed was a thin walled corrugated section which showed higher stiffness than other cross-sections for the same cross-sectional area (i.e. box, I, and rectangular sections). A cold setting, hand layings technique was used in manufacturing these beams wbich were of nine types depending on the type of glass reinforcement employed and the arrangement of layers in the beam. The simple bending theory was used in the beam design and proved to be satisfactory in predicting the stresses and deflections. A factor of safety of 4 was chosen for design purposes and considered to be suitable for long term use under static load. Because of its relatively low modulus, GRP beams allowable deflection was limited to 1/120th of the span which was found to be adequate for design purposes. A general discussion of the behaviour of GRP composites and their place relative to the more conventional structural material was also presented in the thesis.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Speed's theory makes two predictions for the development of analogical reasoning. Firstly, young children should not be able to reason analogically due to an undeveloped PFC neural network. Secondly, category knowledge enables the reinforcement of structural features over surface features, and thus the development of sophisticated, analogical, reasoning. We outline existing studies that support these predictions and highlight some critical remaining issues. Specifically, we argue that the development of inhibition must be directly compared alongside the development of reasoning strategies in order to support Speed's account. © 2010 Psychology Press.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The diagnosis and monitoring of ocular disease presents considerable clinical difficulties for two main reasons i) the substantial physiological variation of anatomical structure of the visual pathway and ii) constraints due to technical limitations of diagnostic hardware. These are further confounded by difficulties in detecting early loss or change in visual function due to the masking of disease effects, for example, due to a high degree of redundancy in terms of nerve fibre number along the visual pathway. This thesis addresses these issues across three areas of study: 1. Factors influencing retinal thickness measures and their clinical interpretation As the retina is the principal anatomical site for damage associated with visual loss, objective measures of retinal thickness and retinal nerve fibre layer thickness are key to the detection of pathology. In this thesis the ability of optical coherence tomography (OCT) to provide repeatable and reproducible measures of retinal structure at the macula and optic nerve head is investigated. In addition, the normal physiological variations in retinal thickness and retinal nerve fibre layer thickness are explored. Principal findings were: • Macular retinal thickness and optic nerve head measurements are repeatable and reproducible for normal subjects and diseased eyes • Macular and retinal nerve fibre layer thickness around the optic nerve correlate negatively with axial length, suggesting that larger eyes have thinner retinae, potentially making them more susceptible to damage or disease • Foveola retinal thickness increases with age while retinal nerve fibre layer thickness around the optic nerve head decreases with age. Such findings should be considered during examination of the eye with suspect pathology or in long-term disease monitoring 2. Impact of glucose control on retinal anatomy and function in diabetes Diabetes is a major health concern in the UK and worldwide and diabetic retinopathy is a major cause of blindness in the working population. Objective, quantitative measurements of retinal thickness. particularly at the macula provide essential information regarding disease progression and the efficacy of treatment. Functional vision loss in diabetic patients is commonly observed in clinical and experimental studies and is thought to be affected by blood glucose levels. In the first study of its kind, the short term impact of fluctuations in blood glucose levels on retinal structure and function over a 12 hour period in patients with diabetes are investigated. Principal findings were: • Acute fluctuations in blood glucose levels are greater in diabetic patients than normal subjects • The fluctuations in blood glucose levels impact contrast sensitivity scores. SWAP visual fields, intraocular pressure and diastolic pressure. This effect is similar for type 1 and type 2 diabetic patients despite the differences in their physiological status. • Long-term metabolic control in the diabetic patient is a useful predictor in the fluctuation of contrast sensitivity scores. • Large fluctuations in blood glucose levels and/or visual function and structure may be indicative of an increased risk of development or progression of retinopathy 3. Structural and functional damage of the visual pathway in glaucomatous optic neuropathy The glaucomatous eye undergoes a number of well documented pathological changes including retinal nerve fibre loss and optic nerve head damage which is correlated with loss of functional vision. In experimental glaucoma there is evidence that glaucomatous damage extends from retinal ganglion cells in the eye, along the visual pathway, to vision centres in the brain. This thesis explores the effects of glaucoma on retinal nerve fibre layer thickness, ocular anterior anatomy and cortical structure, and its correlates with visual function in humans. Principal findings were: • In the retina, glaucomatous retinal nerve fibre layer loss is less marked with increasing distance from the optic nerve head, suggesting that RNFL examination at a greater distance than traditionally employed may provide invaluable early indicators of glaucomatous damage • Neuroretinal rim area and retrobulbar optic nerve diameter are strong indicators of visual field loss • Grey matter density decreases at a rate of 3.85% per decade. There was no clear evidence of a disease effect • Cortical activation as measured by fMRI was a strong indicator of functional damage in patients with significant neuroretinal rim loss despite relatively modest visual field defects These investigations have shown that the effects of senescence are evident in both the anterior and posterior visual pathway. A variety of anatomical and functional diagnostic protocols for the investigation of damage to the visual pathway in ocular disease are required to maximise understanding of the disease processes and thereby optimising patient care.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Theoretical and empirical studies show that deindustrialisation, broadly observed in developed countries, is an inherent part of the economic development pattern. However, post-communist countries, while being only middle-income economies, have also experienced deindustrialisation. Building on the model developed by Rowthorn and Wells (1987) we explain this phenomenon and show that there is a strong negative relationship between the magnitude of deindustrialisation and the efficiency and consistency of market reforms. We also demonstrate that reforms of the agricultural sector play a significant role in placing a transition country on a development path that guarantees convergence to EU employment structures.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The aim of this paper is to model the evolution of employment structure in post-communist economies in the broader context of deindustrialisation. The paper builds on the model of structural change developed by Rowthorn and Wells (1987). We show that the starting point of high industry sector share in total employment and its direct fall when productivity of sectors changes in favour of services can be explained in terms of this framework. Moreover, the model can also describe the phenomenon of a further expansion of the agriculture, observed in countries classified as "less consistent" in the reforms implementation. Hence, we distinguish two development paths, the efficient one, called "horizontal", and the inefficient one called "vertical". We illustrate it with empirical data, using alternative measures of structural change and patterns of structural evolutions during transition. Finally, we discuss the link between the EBRD indicators of reforms and structural change. We show that the "quality" of reforms, not the initial GDP level determines a country's development path.