9 resultados para Land use, development, and construction
em Aston University Research Archive
Resumo:
This article investigates the relationship between zoning by-laws, as put forward in governmental land-use plans and the viability of urban residential neighbourhood economies. The Dutch planning tradition has long been characterized by strict separation of functions and top-down planning. We argue that profound changes in social and economic structures make land-use planning practices less suitable for the current policy formula of "mixed urban milieus". Although the residential neighbourhood might not be the location of large firms, it definitely attracts small ones, and facilitates starting businesses whose presence (and potential growth) can be beneficial to the city as a whole. We present a typology of spatial patterns of neighbourhood economies based on land-use plans and describe whether these are related to the distinctive economic development of the neighbourhood over the period 1999-2007. © 2013 Taylor & Francis.
Resumo:
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Resumo:
Policy towards planning presents scholars of politics and public policy with a significant puzzle. Since 1947, there has been a surprising level of stability in the system used to plan the use of land. On the other hand, there has been growing evidence that insufficient land has been released for development. The paper considers the question why, in spite of the planning system demonstrably failing to allocate sufficient land, fundamental reform of the system has not been achieved. In answering the question, the paper considers in particular attempts at reform under the Labour governments from 1997 to 2010. It argues that there is an interplay of interests, ideas and institutions: public attitudes, the interests of certain sections of the population, and institutions which are responsive to these attitudes and interests combined to stymie policy reform. As a consequence, radical reform was not achieved, and the paper concludes that attempt to find a technical “fix” to the planning system are unlikely to succeed. A diagnosis recognising the political and distributive nature of the problem will be required.
Resumo:
SINNMR (Sonically Induced Narrowing of the Nuclear Magnetic Resonance spectra of solids), is a novel technique that is being developed to enable the routine study of solids by nuclear magnetic resonance spectroscopy. SINNMR aims to narrow the broad resonances that are characteristic of solid state NMR by inducing rapid incoherent motion of solid particles suspended in a support medium, using high frequency ultrasound in the range 2-10 MHz. The width of the normal broad resonances from solids are due to incomplete averaging of several components of the total spin Hamiltonian caused by restrictions placed on molecular motion within a solid. At present Magic Angle Spinning (MAS) NMR is the classical solid state technique used to reduce line broadening, but: this has associated problems, not least of which is the appearance of many spinning side bands which confuse the spectra. It is hoped that SlNNMR will offer a simple alternative, particularly as it does not reveal spinning sidebands The fundamental question concerning whether the use of ultrasound within a cryo-magnet will cause quenching has been investigated with success, as even under the most extreme conditions of power, frequency and irradiator time, the magnet does not quench. The objective of this work is to design and construct a SINNMR probe for use in a super conducting cryo-magnet NMR spectrometer. A cell for such a probe has been constructed and incorporated into an adapted high resolution broadband probe. It has been proved that the cell is capable of causing cavitation, up to 10 MHz, by running a series of ultrasonic reactions within it and observing the reaction products. It was found that the ultrasound was causing the sample to be heated to unacceptable temperatures and this necessitated the incorporation of temperature stabilisation devices. Work has been performed on the investigation of the narrowing of the solid state 23Na spectrum of tri-sodium phosphate using high frequency ultrasound. Work has also been completed on the signal enhancement and T1 reduction of a liquid mixture and a pure compound using ultrasound. Some preliminary "bench" experiments have been completed on a novel ultrasonic device designed to help minimise sample heating. The concept involves passing the ultrasound through a temperature stabilised, liquid filled funnel that has a drum skin on the end that will enable the passage of ultrasound into the sample. Bench experiments have proved that acoustic attenuation is low and that cavitation in the liquid beyond the device is still possible.
Resumo:
The objective of the research carried out in this report was to observe the first ever in-situ sonochemical reaction in the NMR Spectrometer in the megahertz region of ultrasound. Several reactions were investigated as potential systems for a sonochemical reaction followed by NMR spectroscopy. The primary problem to resolve when applying ultrasound to a chemical reaction is that of heating. Ultrasound causes the liquid to move and produces 'hot spots' resulting in an increase in sample temperature. The problem was confronted by producing a device that would counteract this effect and so remove the need to account for heating. However, the design of the device limited the length of time during which it would function. Longer reaction times were required to enable observations to be carried out in the NMR spectrometer. The fIrst and most obvious reactions attempted were those of the well-known ultrasonic dosimeter. Such a reaction would, theoretically, enable the author to simultaneously observe a reaction and determine the exact power entering the system for direct comparison of results. Unfortunately, in order to monitor the reactions in the NMR spectrometer the reactant concentrations had to be signifIcantly increased, which resulted in a notable increase in reaction time, making the experiment too lengthy to follow in the time allocated. The Diels-Alder Reaction is probably one of the most highly investigated reaction systems in the field of chemistry and it was this to which the author turned her attention. Previous authors have carried out ultrasonic investigations, with considerable success, for the reaction of anthracene with maleic anhydride. It was this reaction in particular that was next attempted. The first ever sonochemically enhanced reaction using a frequency of ultrasound in the megahertz (MHz) region was successfully carried out as bench experiments. Due to the complexity of the component reactants the product would precipitate from the solution and because the reaction could only be monitored by its formation, it was not possible to observe the reaction in the NMR spectrometer. The solvolysis of 2-chloro-2-methylpropane was examined in various solvent systems; the most suitable of which was determined to be aqueous 2-methylpropan-2-ol. The experiment was successfully enhanced by the application of ultrasound and monitored in-situ in the NMR spectrometer. The increase in product formation of an ultrasonic reaction over that of a traditional thermal reaction occurred. A range of 1.4 to 2.9 fold improvement was noted, dependent upon the reaction conditions investigated. An investigation into the effect of sonication upon a large biological molecule, in this case aqueous lysozyme, was carried out. An easily observed effect upon the sample was noted but no explanation for the observed effects could be established.
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The northern half of the parish of St. Catherine in Jamaica was selected as a test area to study, by means of remote sensing, the problems of soil erosion in a tropical environment. An initial study was carried out to determine whether eroded land within this environment could be successfully interpreted and mapped from the available 1: 25,000 scale aerial photographs. When satisfied that a sufficiently high percentage of the eroded land could be interpreted on the aerial photographs the main study was initiated. This involved interpreting the air photo cover of the study area for identifying and classifying land use and eroded land, and plotting the results on overlays on topographic base maps. These overlays were then composited with data on the soils and slopes of the study area. The areas of different soil type/slope/land use combinations were then measured, as was the area of eroded land for each of these combinations. This data was then analysed in two ways. The first way involved determining which of the combinations of soil type, slope and land use were most and least eroded and, on the basis of this, to draw up recommendations concerning future land use. The second analysis was aimed at determining which of the three factors, soil type, slope and land use, was most responsible for determining the rate of erosion. Although it was possible to show that slope was not very significant in determining the rate of erosion, it was much more difficult to separate the effects of land use and soil type. The results do, however, suggest that land use is more significant than soil type in determining the rate of erosion within the study area.
Resumo:
This study is concerned with quality and productivity aspects of traditional house building. The research focuses on these issues by concentrating on the services and finishing stages of the building process. These are work stages which have not been fully investigated in previous productivity related studies. The primary objective of the research is to promote an integrated design and construction led approach to traditional house building based on an original concept of 'development cycles'. This process involves the following: site monitoring; the analysis of work operations; implementing design and construction changes founded on unique information collected during site monitoring; and subsequent re-monitoring to measure and assess Ihe effect of change. A volume house building firm has been involved in this applied research and has allowed access to its sites for production monitoring purposes. The firm also assisted in design detailing for a small group of 'experimental' production houses where various design and construction changes were implemented. Results from the collaborative research have shown certain quality and productivity improvements to be possible using this approach, albeit on a limited scale at this early experimental stage. The improvements have been possible because an improved activity sampling technique, developed for, and employed by the study, has been able to describe why many quality and productivity related problems occur during site building work. Experience derived from the research has shown the following attributes to be important: positive attitudes towards innovation; effective communication; careful planning and organisation; and good coordination and control at site level. These are all essential aspects of quality led management and determine to a large extent the overall success of this approach. Future work recommendations must include a more widespread use of innovative practices so that further design and construction modifications can be made. By doing this, productivity can be improved, cost savings made and better quality afforded.