114 research outputs found

    Selection of mu-mesons by a ÄŒerenkov counter system and an investigation of the interactions produced by them in lead plates in a Wilson cloud chamber

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    In this chapter, the conclusions drawn from the experiments will be stated, and the future uses of the counter system will be discussed.It will to obvious from the results that a .,as ÄŒerenkov counter system of the type described, is an extremely useful tool for the detection of muons in the high energy range. The most useful property of the counter is of course, its velocity dependence. This has certain advantages over other selecting arrangements, which select on a momentum basis, e.g. elimination of contamination in beam experiments.It had been shown that at 10 atmospheres pressure, the large ÄŒerenkov counter can select particles which are 0.0009c above the threshold velocity. This threshold is set by the least number of photons which can be .elected by the photomultiplier (90). If Figure (6.1) is considered the properties and limitations of the ÄŒerenkov counters can b e seen over a wide range of momenta. The table shown below has been calculated from Figure (4.1), which snows the increase in photon number with increasing momentum. It is calculated on the basis of a 100 cm. long sensitive length. As has been stated before, the practical threshold momentum is displaced further from the theoretical threshold with increasing momentum. In fact, with such a counter, it is possible that even if the particle is travelling with the velocity of light, insufficient photons will be produced to give a count. The only thing which can be done to rectify this situation is to increase the length of the counters. If, for example, a particle of momentum as high as 20 Gev./c was to be selected with an atmospheric pressure counter, it would have to be 4.8 metres long, and of such design to collect all the photons produced in the sensitive region. Of course, such a counter should theoretically select all particles above 4.5 Gev./c and thus the spread is becoming very large. It is this effect which puts a practical high momentum limit on the counters, and 20 Gev./c would certainly be the upper limit to any type of counter which we would consider possible to design.Pulse height discrimination at these higher momentum values is also impossible, as can be seen from Figure (4.1), as the curves flatten out after a sharp initial rise. At the higher momentum values the increase in photon number with increasing momentum is extremely slow.Tne experiments using cosmic radiation are at a great disadvantage compared to experiments using machine intensities. There fore, the fundamental interest is in being able to select particles in an energy range above the limits of the present accelerators. It does not therefore, appear possible to do this with a ÄŒerenkov counter system alone. A combination of ÄŒerenkov counters and ionisation counters using the relativistic rise in the latter, is being considered for future use. With such an arrangement, it might be found possible to select muons with an energy greater than those produced by accelerators

    Physical systems with time varying parameters

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    Improving proteomic methods and investigating H2 production in Synechocystis sp. PCC6803

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    The annual EU consumption of energy is approaching 3 Terawatt.hr−1, but the majority of this is powered by fossil fuel. Burning of fossil fuels has produced a global catastrophe, climate change, and carbon-free replacement technologies are urgently required to prevent this from becoming worse in the coming years. The CyanoFactory consortium worked to optimise the organism Synechocystis sp. PCC6803 (herein Synechocystis) to produce industrially relevant levels of bio-hydrogen as one such potential solution. This thesis discusses aspects of this ambitious project, focusing on understanding and optimising the internal protein network of the organism to engineer a functional and efficient system. Synechocystis is a model cyanobacteria – and so has a significant body of research associated with it compared with other cyanobacteria, but is nowhere near as well studied as the other major model organisms such as E. coli or S. cerevisiae – particularly in protein-level studies, although this is changing with time. Whole-proteome studies are highly advanced in medical applications, however bioengineering using proteomics still lags behind studies which directly measure individual proteins, metabolic outputs, or nucleic acid studies. A number of proposals emerge from the literature as the most effective way to move forward, part of which is filling the gaps in the literature for Synechocystis and production strains in general. The major improvement missing from this field is the broad-spectrum inclusion of broadly applicable bioengineering techniques, such as synthetic biology, being integrated with whole-proteome studies, rather than just focusing on individual pathways. This gap is likely to be filled in the near future, with the recent improvements to proteomic technologies and the increasing popularity of the methodology – which has seen a sharp increase since the start of 2015. The current gap between the medical studies and production strains provides an opportunity to test a variety of different approaches, that look more at general whole-cell level responses rather than targeted observations. These gaps in knowledge are assessed herein, and new methods for analysing Synechocystis specifically are proposed. These proposals cover both alterations to the practical protocol, including physically lysing cells based on meta-analysis of the literature with experimental verification, more accurate methods of determining protein levels – which are generally complicated by coloured compounds found in cyanobacteria; and computational protocols for improving the quantity, quality and relevance of the data obtained, including better observation of low-abundance proteins in a complex background, assessment and recommendations for expanding the number of different samples that can be measured simultaneously, and simpler tools for identifying broad-sweeping changes, where metabolic-network derived investigations are unsuitable. Isobaric tags are popular methods for analysing the relative quantity of proteins observed in a cell-wide sample, however there are different technologies for this method. The two most popular tag-based quantification technologies – iTRAQ and TMT – are directly compared, to determine which method is more suitable for analyses in Synechocystis. The study was focused on Synechocystis, however the observations are also more generally applicable to other investigations. To perform this study, a modelled assessment of the ‘proteomic background’ of Synechocystis was carried out, providing an impression of the internal proteome distribution – a valuable set of information for carrying out more accurate engineering of the internal mechanisms with technologies, such as Synthetic Biology. The study found that whilst TMT tags generally produced more quantifications, the iTRAQ tags were more accurate over a greater range – however to take advantage of this would require a larger number of repeated injections of the iTRAQ samples, producing a relatively inflated cost for better quality data. Combining these tools, a direct assessment was carried out of the systemic changes that occur in Synechocystis under hydrogen-producing conditions, along with an assessment of a media proposed for optimised H2 production. This experiment first carried out with the methods used more widely at the start of this analysis, and the second was conducted afterwards, utilising many of the methodological improvements proposed in this thesis. Ultimately, an increase in data quantity and quality was observed. As hydrogen production is a response to a change of conditions, the pathway-level assessment of the proteome changes show a concordant switch between 2 very clear states under the experimental conditions used. This suggests that finding a way to produce hydrogen directly – under normal growth conditions in light – will be extremely challenging as it fundamentally competes with the growth and function of the organism; however an integrated approach, merging the production of high-value side products during the day, coupled with hydrogen production at night for generating power to run the bioreactor system, has a much greater chance of success. A decision on which products should be targeted to make the system economically viable will dictate further analysis of the data. The major conclusions of this work show that the suggested improvements are beneficial to proteomic studies in Synechocystis, producing an improvement to quantity, quality and accessibility of proteomic data. These observations have been applied to hydrogen production systems, demonstrating that whilst bio-hydrogen is unlikely to be the white knight that will save the world from climate change, it can be integrated into large-scale production systems to improve energy efficiency – where the energy saved can reduce costs and power-inputs required from carbon-based fuels. The methods suggested here, whilst ultimately adding little to the assessment of H2 production, have huge potential when integrated into future project focused on the production of more economically viable complex organic molecules or fine chemicals

    An energy and resource efficient alkaline flocculation and sedimentation process for harvesting of Chromochloris zofingiensis biomass

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    Harvesting microalgal cultures is often energetically intensive and costly. To improve efficiencies, a two-step harvesting method utilising alkaline flocculation and sedimentation to pre-concentrate cultures can be used prior to centrifugation. When applied to the microalga Chromochloris zofingiensis, high rates of sedimentation (>90%) were found at low concentrations of base (<10 mM), with the addition of magnesium to the media (via NaOH/MgSO4 or Ca(OH)2/Mg(OH)2) to form Mg(OH)2. The process was scaled to 180 L, where sedimentation was as efficient as that achieved at bench scale. Characterisation of the harvested biomass showed comparable composition (following neutralisation of pH) to biomass recovered solely by centrifugation. The alternative two-step processes were assessed for environmental impacts and cost, which indicated that a two-step harvesting generally performs better than centrifugation alone, but that the locally available electricity source is a critical parameter for optimal solution

    A River Runs Through It: Imagining the future of the Glasgow City Region & the Clyde Valley: A Design Sprint

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    The Clyde and its tributaries run through the eight local authorities of the Glasgow City Region that together have a population of just under 2 million (1.87m) making up nearly 40% (37%) of Scotland’s population. As a holistic ecosystem, the Clyde and its tributaries is today a widely unappreciated waterway network throughout the entire city-region. In the vocabulary of the Resilient City Network (Rockefeller Foundation), the River Clyde has the potential to create both ‘stress’ and ‘shock’ in the metropolitan city-region of Glasgow, primarily as a result of flood risk which manifests in two ways: the first from downstream flow following serious precipitation events, and the second from upstream flow associated with increased sea levels as a consequence of climate change. There is a clear and present need to address both flows and ‘space’ for the river. There have been a number of initiatives for the river, but there has never been a single piece of visioning work that seeks to consider the future of the river as a rural and urban ecosystem from its source to the sea, that relates to the settlement pattern through which it passes, in concert with the strategic challenges of the transportation networks, and the networks of vacant and derelict land and stranded assets lying within the post-industrial metropolitan area of the Glasgow city region

    Consumer Experiences of the Cost-of-Living Crisis

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    The cost-of-living crisis is a fundamental challenge to Scottish society, both in terms of personal health and well-being, and social cohesion. The crisis brings to the fore structural problems in Scotland and similar countries, building on a combination of neoliberal market economy and state-funded support mechanisms.Millions of families in Scotland and across the UK live on disposable incomes that cannot cover the cost of rising food and energy bills. The Joseph Rowntree Foundation1 have recently documented the persistence of the crisis for low-income families with millions continuing to go without essentials, and destitution in the UK more than doubling since 2017. Although the crisis has been most severe for low-income families particularly those living on universal credit, it has also impacted the working-poor for whom full-time employment is insufficient to cover the cost of living. As such, the cost-of-living crisis indicates deep flaws in contemporary society.A viable solution will have to address the root causes and, thereby, requires substantive political intervention and, some might argue, systemic change. However, until such solutions are designed and implemented, consumers are largely left to their own devices.This report discusses how consumers from various backgrounds across Scotland have experienced the cost-of-living crisis. Giving voice and perspective to the lived experience of the cost-of-living crisis is important: it gives concrete insights into the personal, emotional and psychological reality of poverty; it reveals the potential and limitation of consumer coping and resilience; and it offers a sense of hope that if we are willing to overcome entrenched ideologies and work across various stakeholder priorities, real change is possible.Metho

    Development of the escape response in teleost fishes: do ontogenetic changes enable improved performance?

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    Teleost fishes typically first encounter the environment as free-swimming embryos or larvae. Larvae are morphologically distinct from adults, and major anatomical structures are unformed. Thus, larvae undergo a series of dramatic morphological changes until they reach adult morphology (but are reproductively immature) and are considered juveniles. Free-swimming embryos and larvae are able to perform a C-start, an effective escape response that is used evade predators. However, escape response performance improves during early development: as young fish grow, they swim faster (length-specific maximum velocity increases) and perform the escape more rapidly (time to complete the behavior decreases). These improvements cease when fish become juveniles, although absolute swimming velocity (m s(-1)) continues to increase. We use studies of escape behavior and ontogeny in California halibut (Paralichthys californicus), rainbow trout (Oncorhynchus mykiss), and razorback suckers (Xyrauchen texanus) to test the hypothesis that specific morphological changes improve escape performance. We suggest that formation of the caudal fin improves energy transfer to the water and therefore increases thrust production and swimming velocity. In addition, changes to the axial skeleton during the larval period produce increased axial stiffness, which in turn allows the production of a more rapid and effective escape response. Because escape performance improves as adult morphology develops, fish that enter the environment in an advanced stage of development (i.e., those with direct development) should have a greater ability to evade predators than do fish that enter the environment at an early stage of development (i.e., those with indirect development)

    Consumer Experiences of the Cost-of-Living Crisis

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    The cost-of-living crisis is a fundamental challenge to Scottish society, both in terms of personal health and well-being, and social cohesion. The crisis brings to the fore structural problems in Scotland and similar countries, building on a combination of neoliberal market economy and state-funded support mechanisms.Millions of families in Scotland and across the UK live on disposable incomes that cannot cover the cost of rising food and energy bills. The Joseph Rowntree Foundation1 have recently documented the persistence of the crisis for low-income families with millions continuing to go without essentials, and destitution in the UK more than doubling since 2017. Although the crisis has been most severe for low-income families particularly those living on universal credit, it has also impacted the working-poor for whom full-time employment is insufficient to cover the cost of living. As such, the cost-of-living crisis indicates deep flaws in contemporary society.A viable solution will have to address the root causes and, thereby, requires substantive political intervention and, some might argue, systemic change. However, until such solutions are designed and implemented, consumers are largely left to their own devices.This report discusses how consumers from various backgrounds across Scotland have experienced the cost-of-living crisis. Giving voice and perspective to the lived experience of the cost-of-living crisis is important: it gives concrete insights into the personal, emotional and psychological reality of poverty; it reveals the potential and limitation of consumer coping and resilience; and it offers a sense of hope that if we are willing to overcome entrenched ideologies and work across various stakeholder priorities, real change is possible.Metho

    Development of Vortex Bioreactor Technology for Decentralised Water Treatment

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    The vortex bioreactor (VBR) is a simple decentralised water treatment system (DeWaTS) that sits at the interface between swirl flow, biotechnology and chemical engineering. The device utilises swirl flow and suspended activated beads to achieve downstream water processing and has been tested for applications including centrifugal-driven separation, pathogen neutralisation and metal absorption. The VBR was optimised for the treatment of faecally contaminated effluents in the developing world, and the design features related to the key challenges faced by the wastewater industry are highlighted here. The VBR has two aspects that can be modified to generate different reactor conditions: the impeller, where the swirl flow is modified through alterations of rotation speed, and impeller geometry and the suspended activated beads, which facilitate mixing and alter the reactor surface area. Data from testing for some of the different applications mentioned above are presented here, and future planned developments for the technology are discussed

    An energy and resource efficient alkaline flocculation and sedimentation process for harvesting of Chromochloris zofingiensis biomass

    Get PDF
    Harvesting microalgal cultures is often energetically intensive and costly. To improve efficiencies, a two-step harvesting method utilising alkaline flocculation and sedimentation to pre-concentrate cultures can be used prior to centrifugation. When applied to the microalga Chromochloris zofingiensis, high rates of sedimentation (> 90%) were found at low concentrations of base (< 10 mM), with the addition of magnesium to the media (via NaOH/ MgSO4 or Ca(OH)2/Mg(OH)2) to form Mg(OH)2. The process was scaled to 180 L, where sedimentation was as efficient as that achieved at bench scale. Characterisation of the harvested biomass showed comparable com�position (following neutralisation of pH) to biomass recovered solely by centrifugation. The alternative two-step processes were assessed for environmental impacts and cost, which indicated that a two-step harvesting gen�erally performs better than centrifugation alone, but that the locally available electricity source is a critical parameter for optimal solutio
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