668 research outputs found

    The effect of epoxy resins on the plasticity index of an A-6 soil

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    This thesis reports the results of an investigation of the variation in plasticity of a clayey soil after treatment with small quantities of epoxy resin and curing agent or with curing agent alone. The series of samples tested consisted of an A-6 soil obtained from the vicinity of Rolla, Missouri, combined with: 1. 0-3% of triethylenetetramine hereafter referred to as TETA. 2. 0-3% of diethylenetriamine hereafter referred to as DETA. 3. 0-3% of Araldite 6010 resin cured with TETA. The TETA content was varied form 20% to 100% of the resin by weight. 4. 0-3% Araldite 6010 resin cured with DETA. The DETA content was varied from 20% to 100% of the resin by weight. The plasticity index of the treated soil samples was computed by conventional soil testing procedures. The relative amount of unreacted amine remaining in samples was determined by titration. Qualitative relationships were found between the plasticity index and the type and quantity of additive used. The complexities of these relationships are discussed and suggestions for further research are made --Abstract, page ii

    Domain Architectures as an Instrument to Refine Enterprise Architecture

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    Enterprise architecture is concerned with the fundamental organization of the operating environment of an enterprise. The enterprise architecture is used to plan and control the construction of the systems that populate the operating environment. As the scope covered can be considerable in large enterprises, introducing domain architectures to partition and detail the enterprise architecture is a plausible approach. We formulate prescriptive criteria that consistent domain architectures must meet. By integrating the creation of domain architectures into an extended strategic alignment model we develop a theory that accounts for both the creation, scope-setting and detailing. Based on the creation viewpoint we derive a multi-level classification taxonomy. The primary differentiator is that between domains that are created from business usage viewpoints and those that are created from solution construction viewpoints. Four cases of domain architectures from actual practice are described that illustrate the variety encountered. Domain classifications in all cases conform to the theoretical model. The criteria, the developed theory and the cases have both academic relevance as well as significance for practitioners

    Investigation of Performance and Cavitation Treatment in a Kaplan Hydro Turbine

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    Cavitation is a phenomenon that occurs in various turbomachinery applications causing drawbacks on the. Some of these downsides are damaging the components of the system, generating noise and vibration, and loss of the turbine efficiency over time. Thus, it is imperative to address issue of cavitation to increase the life span of the equipment in addition to improve the system performance. This thesis introduces a method used to mitigate the cavitation phenomenon in a 3-inch Kaplan hydro turbine via injecting air at the leading edge of the rotor blades. The study is based on modeling the turbine using Computational Fluid Dynamics (CFD) software as well as carrying out experimental tests. The simulations were conducted at different air injection pressures over a spectrum of rotational speeds using Large Eddy Simulation (LES) for turbulence and volume of fluid for multiphase interactions: water, vapor water and air. The cavitation behavior was observed first without aeration, then followed by air injection simulations to investigate the effect of aeration. Each case was simulated for 12 cycles at rotational speeds of 1000, 2000, 3000, 4000, and 5000 rpm. The Vapor Volume Fraction (VVF) and the output mechanical power were monitored throughout the simulations. The data acquired from the simulations were compared to the experimental results for verifications. It was observed that the cavitation was mitigated in both the computer simulations and the experiment testing reaching up to 49.7% as an average reduction, while the output power was reduced by 6.6%

    Prevention of tick bites: an evaluation of a smartphone app.

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    Lyme borreliosis (LB) is the most common reported tick-borne infection in Europe, and involves transmission of Borrelia by ticks. As long as a vaccine is not available and effective measures for controlling tick populations are insufficient, LB control is focused on preventive measures to avoid tick bites. To inform citizens about the risk of ticks, motivate them to check for tick bites, and encourage them to remove any attached tick as quickly as possible, a mobile app called 'Tekenbeet' (Dutch for 'tick bite') was developed and released. The aim of this study was to evaluate the usage and user satisfaction of the 'Tekenbeet' app and to investigate whether it affects users' knowledge, perceived severity, perceived susceptibility, self-efficacy, response efficacy, current behavior and intention to comply with preventive measures

    Sequential gene promoter methylation during HPV-induced cervical carcinogenesis

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    We aimed to link DNA methylation events occurring in cervical carcinomas to distinct stages of HPV-induced transformation. Methylation specific-multiplex ligation-dependent probe amplification (MS-MLPA) analysis of cervical carcinomas revealed promoter methylation of 12 out of 29 tumour suppressor genes analysed, with MGMT being most frequently methylated (92%). Subsequently, consecutive stages of HPV16/18-transfected keratinocytes (n=11), ranging from pre-immortal to anchorage-independent phenotypes, were analysed by MS-MLPA. Whereas no methylation was evident in pre-immortal cells, progression to anchorage independence was associated with an accumulation of frequent methylation events involving five genes, all of which were also methylated in cervical carcinomas. TP73 and ESR1 methylation became manifest in early immortal cells followed by RARβ and DAPK1 methylation in late immortal passages. Complementary methylation of MGMT was related to anchorage independence. Analysis of nine cervical cancer cell lines, representing the tumorigenic phenotype, revealed in addition to these five genes frequent methylation of CADM1, CDH13 and CHFR. In conclusion, eight recurrent methylation events in cervical carcinomas could be assigned to different stages of HPV-induced transformation. Hence, our in vitro model system provides a valuable tool to further functionally address the epigenetic alterations that are common in cervical carcinomas

    Groundwater resources in the Indo-Gangetic Basin : resilience to climate change and abstraction

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    Groundwater within the Indo‐Gangetic Basin (IGB) alluvial aquifer system forms one of the world’s most important and heavily exploited reservoirs of freshwater. In this study we have examined the groundwater system through the lens of its resilience to change – both from the impact of climate change and increases in abstraction. This has led to the development of a series of new maps for the IGB aquifer, building on existing datasets held in Pakistan, India, Nepal and Bangladesh, a review of approximately 500 reports and papers, and three targeted field studies on under‐researched topics within the region. The major findings of the study are described below. The IGB groundwater system 1. The IGB alluvial aquifer system comprises a large volume of heterogeneous unconsolidated sediment in a complex environmental setting. Annual rainfall varies from 2000mm in the Bengal basin, and the system is dissected by the major river systems of the Indus, Ganges and Brahmaputra. The groundwater system has been modified by the introduction of large scale canal irrigation schemes using water from the Indus and Ganges since the 19th and early 20th centuries. 2. High yielding tubewells can be sustained in most parts of the alluvial aquifer system; permeability is often in the range of 10 – 60 m/d and specific yield (the drainable porosity) varies from 5 – 20%, making it highly productive. 3. High salinity and elevated arsenic concentrations exist in parts of the basin limiting the usefulness of the groundwater resource. Saline water predominates in the Lower Indus, and near to the coast in the Bengal Delta, and is also a major concern in the Middle Ganges and Upper Ganges (covering much of the Punjab Region in Pakistan, southern Punjab, Haryana and parts of Uttar Pradesh in India). Arsenic severely impacts the development of shallow groundwater in the fluvial influenced deltaic area of the Bengal Basin. 4. Recharge to the IGB aquifer system is substantial and dynamic, controlled by monsoonal rainfall, leakage from canals, river infiltration and irrigation returns. Recharge from rainfall can occur even with low annual rainfall (350 mm) and appears to dominate where rainfall is higher (> 750 mm). Canal leakage is also highly significant and constitutes the largest proportion of groundwater recharge in the drier parts of the aquifer, partially mitigating the effects of abstraction on groundwater storage. 5. Deep groundwater (>150 m) in the Bengal basin has strategic value for water supply, health and economic development. Excessive abstraction poses a greater threat to the quality of this deep groundwater than climate change. Heavy pumping may induce the downward migration of arsenic in parts of Bangladesh, and of saline water in coastal regions, but field evidence and modelling both suggest that deep groundwater abstraction for public water supply in southern Bangladesh is in general secure against widespread ingress of arsenic and saline water for at least 100 years
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