Clay-rich till plains cover much of the U.K. Such sites are attractive locations for landfills, since clay aquitards lower the risk of landfill leachate entering groundwater. However, such tills often contain sand and gravel bodies that can act as leachate flow routes. Such bodies may not be detected by conventional site investigation techniques such as drilling boreholes and trial pitting. A method of b'llided inversion, where a priori data are used to construct reference models for use in inverting electrical resistivity tomography (ERT) data, was proposed as a tool to improve the detection of sand and gravel bodies within clay-rich till sequences. Following a successful 2D guided inversion synthetic modelling study, a field study was undertaken. Seven parallel Venner 2D ERT lines, 11 resistivity cone penetrometry (RCPT) bores and electromagnetic (E1'.I) induction gTOlllld resistivity data were collected over a 72001112 site at Holmpton on the East Yorkshire coast, where at least two sand and gravel lenses were known to exist from cliff exposures. A 41-electrode section of one ERT line that passed over a sand and gravel body 20 m wide and 1m thick at a depth of 5m was chosen to test the guided inversion approach. The EM data determined the width of the body in the reference model and individual RCPTs determined the background resistivity, and the body resistivity and thickness. It was shown for the first time that the best solution model produced by 2D inversion of one dataset with a range of reference models could be determined by using the l2 model misfit between the solution modeL,> and associated reference models (reference misfit) as a proxy for the l2 misfit between the solution models and the synthetic model (true misfit). For a 2.5D study based on the same field data, the reference misfits and true misfits were poorly correlated. This is possibly because the true 3D geoelectrical structure of the field study site is not sufficiently well known to enable comparisons between the solution models and the true geoelectrical structure of the ground. The 2D methodology developed here is applicable in clay-rich till plains containing sand and gravel bodies throughout the U.K.

Particular hygiene applications, such as Moist Toilet Tissue (MTT), toddler wipes, bathroom cleaning wipes 'and feminine hygiene wipes lend themselves to convenient disposal via the sewer network. The high volume of wipes now disposed of through the sewer network is increasing pressure on pipework systems and wastewater treatment plants. The main objectives of this study were to review the prior art and published literature on flushable nonwoven technology, identifying the fundamental mechanisms of function, benchmark the performance of currently available commercial flushable wipes and through experimentation and empirical modeling, begin to form an understanding of flushable wet wipe structure-property relationships. Commercially available wet wipes were found to exhibit varying dispersibilities when assessed using the industry-standard shake-flask test methodology, a test designed to assess the disintegration of a wipe following disposal in the sewer network. All were composed from cellulose, usually blends of wood pulp and lyocell. It was observed that fibrillation of lyocell increased as a result of mechanical agitation during dispersibility testing. These fibrils apparently hindered the dispersion of the wipe into individual fibres. In experimental wipes, fibre fibrillation was found to have a negative influence on the dispersibility behaviour of both wetlaid and airlaid hydroentangled wipes. Hydroentangled fabrics containing non-fibrillating regenerated cellulose fibres exhibited the greatest resistance to fibrillation and also the highest dispersibility. Experiments were performed to assess the wet strength and dispersibility of both wetlaid and airlaid hydroentangled wipes composed of wood pulp and regenerated cellulose. The influence of fabric structure including fibre length, aspect ratio (fineness), blend composition and process (specific energy and hydroentanglement forming belt open area) were studied. Based on the findings from the present work, using an airlaid-hydroentangled platform it is possible to produce a wet wipe with a wet strength as high as 22 N/50mm with dispersibility of 100% (<12.5 mm screen), which exceeds the aspirational target of 15 N/50 mm and ?.95% dispersibility (12.5 mm screen). Empirical models based on linear multiple regression methods suggested specific energy and the total regenerated fibre length positively influence the wet tensile strength of the fabrics. However, the total fibre length negatively influences dispersibility. Fibres that are resistant to fibrillation were found to benefit dispersibility. The model for wet tensile strength was found to have a relatively good correlation with the experimental data, but less so for dispersibility. Furthermore, it was established that the most likely dispersion mechanism in the shake flask is the result of fibre slippage, meaning that wet fibre-to-fibre cohesion and frictional resistance to sliding is critical in governing the break-up of the substrate. To understand the magnitude of the wet cohesive forces involved, a wet pull out test was devised. Airlaidhydroentangled wipes with a carboxymethylcellulose (CMC)' binder exhibited improved dispersibility performance but with decreased wet tensile strength. This could be explained in terms of the modification of the coefficient of friction by the CMC allowing the fibres to separate more easily when subjected to mechanical forces during agitation. Optimum pH conditions and electrolyte addition levels were established for the stabilisation of CMC binder in wetwipes.

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Many proposed and implemented packet classification algorithms trade off JT1emory against lookup-time. Matching algorithms implemented in software cannot keep up with ever-increasing data rates. On the other hand, devices implemented in hardware such as Content Addressable Memory (CAM) have deterministic high lookup rates, but they are expensive in terms of silicon cost and power dissipation. Therefore, a trade-off between hardware and software solutions Le. algorithmic-architectural solutions take advantage of the emerging technologies to provide the required high speed classification without sacrificing the deterministic performance of CAMs. I~ chapter 3 an algorithmic-architectural solution is provided that exploits the geometrical distribution of rules, Hypercuts packet classification algorithm, and CAMs. It works by multi-level cutting ofthe classification space into sub-spaces. It prOVides the deterministic performance of CAMs, support for dynamic updates, and fleXibility for the system designer to trade off the components of the architecture. In chapter 4 Adaptive Rules Cutting (ARC), a heuristic algorithm for packet classification, is proposed. This heuristic algorithm works by selecting the bit positions that divide the classification space into sub-spaces at l-Ievel in a way that reduces the redundancy of rules in cuts and maximizes the equal distribution of rules in cuts. An architecture for packet classification by l-Ievel cutting of the classification space is presented. In chapter 5, architecture for hardware acceleration of session-based IP packet classification is provided and implemented in FPGA. The architecture works by dividing the classification space into sub-spaces at l-Ievel using CRC16. Overall, the thesis provides three new solutions for packet classification based on cutting the classification space into smaller spaces. Supplied by The British Library - 'The world's knowledge'

The high arsenic content of the groundwater in the Holocene aquifer of the Bengal delta plain is unique and elusive in the extent of its exposure causing a threat to the lives of millions of people in the region. The thesis presents a general review on the arsenic contamination of the aquifer in the region with special emphasis on the mobilisation and mitigation issues and stresses the need for the holistic approach for sustainable development of the groundwater resource. A contingent valuation study ( CVM) was conducted to survey the residents of a arsenic affected village about their willingness to pay for arsenic free water in place of arsenic laden water they were getting for drinking and cooking purpose. CVM uses surveys of expressed preferences to evaluate the willingness to pay for non-market, environmental goods. Assured, affordable and sustainable safe water resources are vital for all community to combat an arsenic disaster. Competent water resource management could playa key role to solve the arsenic contamination problem. The study conducted focused on the role of the cooperative and non cooperative extraction of groundwater on sustainable exploitation of a jointly used groundwater resources Water scarcity and its contamination are biggest challenge to the scientific community. The rising cost of generating new supplies and the scarcity of safe and uncontaminated water resource has led to increased emphasis on the better management of the existing water resources. An analysis of deficit irrigation in three quite different situation using five crops viz potato, wheat, maize, onion and sesame was conducted to better understand the potential benefits and risks associated with the irrigation strategy. Crop yield function and crop function were developed and is used to estimate the level applied water that would produce maximum net income in each situation

Chemical precipitation is frequently used in heavy metal removal; it involves the addition of aluminium (III) salts followed by an increase in pH to produce an insoluble hydrous oxide precipitate (floc), which is then easily separable. However, the hydrous oxides are not 100% effective at removing heavy metal contaminants from water at pH 7 and the addition of polymers bearing chelating groups can significantly enhance the adsorption of metals by floes. Silicon polymers bearing chelating groups were designed and synthesized for the enhanced removal of heavy metals from wastewater by floes. A number of synthetic strategies were exploited in the synthesis of these silicone polymers, involving the modification of silanes, cyclic siloxanes and silicone polymers containing vinyl-, halogeno-, hydrido, amino- and mercapto- functionalities. Investigations into the effect of the silicone polymers on the individual adsorption of cadmium, cobalt, manganese and nickel, as well as the simultaneous adsorption of eight heavy metal contaminants by aluminium flocs were performed. Adsorption, studies have shown that the presence of silicone polymers can enhance the removal of these heavy metal ions by aluminium floes to varying extents up to 98%, even when in competition with other heavy metal ions. Cadmium adsorption was greatly enhanced in the presence of a wide range of silicone polymers containing a mixture of functional groups and can be accounted by the fact that it does not show a preference for a particular geometry and can form complexes with oxygen, nitrogen and sulfur donor ligands. The adsorption of manganese, cobalt and nickel was only enhanced in the prescence of certain silicone polymers, depending on the properties of the metal ions and silicone polymer. The results show that the efficiency of the polyelectrolytes in enhancing heavy metal removal depends on the number and type of chelating groups present on the silicone polymer.

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