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Caunce, James Frederick Physical Environmental & Mathematical Sciences Australian Defence Force Academy UNSW. "Mathematical modelling of wool scouring." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2007. http://handle.unsw.edu.au/1959.4/38650.
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Wool scouring is the first stage of wool processing, where unwanted contaminants are removed from freshly shorn wool. In most scouring machines wool is fed as a continuous mat through a series of water-filled scour and rinse bowls which are periodically drained. The purpose of this project is to mathematically model the scour bowl with the aim of improving efficiency. In this thesis four novel models of contaminant concentration within a scour bowl are developed. These are used to investigate the relationships between the operating parameters of the machine and the concentration of contamination within the scour bowl. The models use the advection-diffusion equation to simulate the settling and mixing of contamination. In the first model considered here, the scour bowl is simulated numerically using finite difference methods. Previous models of the scouring process only considered the average steady-state concentration of contamination within the entire scour bowl. This is the first wool scouring model to look at the bowl in two dimensions and to give time dependent results, hence allowing the effect of different drainage patterns to be studied. The second model looks at the important region at the top of the bowl - where the wool and water mix. The governing equations are solved analytically by averaging the concentration vertically assuming the wool layer is thin. Asymptotic analysis on this model reveals some of the fundamental behaviour of the system. The third model considers the same region by solving the governing equations through separation of variables. A fourth, fully two-dimensional, time dependent model was developed and solved using a finite element method. A model of the swelling of grease on the wool fibres is also considered since some grease can only be removed from the fibre once swollen. The swelling is modelled as a Stefan problem, a nonlinear diffusion equation with two moving boundaries, in cylindrical coordinates. Both approximate, analytical and a numerical solutions are found.
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Lu, Xue Fen. "Wool scouring and sludge incineration." Thesis, University of Huddersfield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368210.
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au, C. Bath@murdoch edu, and Caroline Jacobson. "Scouring and Dag in Sheep in Western Australia." Murdoch University, 2006. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070831.155237.
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Diarrhoea (scouring) in sheep increases the risk of faecal soiling of the breech (dag) that in turn causes significant production losses for sheep producers and increases susceptibility of sheep to breech blowfly strike. The common causes of scouring in sheep of post-weaning age in Western Australia have not been well described.
In a written questionnaire sent to sheep producers in the south west of Western Australia, about half of the respondents reported lamb, hogget and ewe flocks with moderate or severe dag. Flocks with moderate or severe dag were reported more commonly in the winter and spring months in all age groups. Young sheep and mated ewes were most susceptible to moderate or severe dag. The utilisation of professional worm control advice and parasite management tools did not reduce the risk of moderate/severe dag.
A study conducted at an abattoir showed that large strongyle worm egg counts (WEC) were frequently identified in lamb lines but were much less common in adult lines. The relationship between WEC and scouring was not clear, suggesting that factors other than large strongyle infections were important, particularly in adult sheep. The low WEC and seasonal scouring pattern observed in adult sheep was consistent with the larval hypersensitivity scouring syndrome and/or factors related to green pasture as potential common causes of scouring in adult sheep. This observation was consistent with detailed investigations of flocks with low WEC scouring that found larval hypersensitivity scouring syndrome or factors associated with green pasture were the most likely causes of scouring in eight of the nine flocks examined. Large immature worm burdens were common and the scouring sheep had more fourth stage larvae than normal sheep. Treatment with a fully effective drench and an ivermectin controlled-release rumen capsule did not result in a reduction of faecal moisture content between three and seven weeks after treatment.
The effects of dietary soluble non-starch polysaccharides were studied using carboxymethylcellulose (CMC) as a model. The CMC model was used to demonstrate that significant interactions between diet and strongyle larvae determined both faecal consistency and strongyle establishment. Sheep fed CMC had softer, looser and wetter faeces, but the factors that determined faecal consistency were complex. Establishment of T. colubriformis was significantly greater in sheep fed CMC suggesting that the environment within the gut may affect establishment of T. colubriformis in the small intestine. The findings suggested that dietary factors may interact with strongyle larvae to determine both worm establishment and severity of scouring.
The results of the studies described in this thesis suggested that factors related to immature strongyle larvae, diet and the immune response interact to determine the severity of the scouring observed in sheep of post-weaning age in the south west of Western Australia.
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Savage, Matthew John. "Integrated Treatment Processes For Primary Wool Scouring Effluent." Thesis, University of Canterbury. Chemical and Process Engineering, 2003. http://hdl.handle.net/10092/1125.
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The increasing cost of effluent treatment in the wool scouring industry is rapidly becoming a determining factor in the viability of existing scouring operations and new installations alike. This thesis details the development of an integrated effluent treatment process capable of treating the worst polluted effluent from a wool scour "heavy flow-down", to the point where it can either be economically discharged to local trade waste sewer, or directly discharged to river or ocean outfall with minimal environmental impact. The existing proprietary chemical flocculation process, Sirolan CF™, was improved by the addition of a bio-flocculation stage and turbidity monitoring and control, and the product from this process fed to an aerobic biological treatment system based upon the traditional activated sludge process. The biological treatment process was found to remove up to 98% of the BOD5 loading from the pre-treated liquor with a hydraulic residence time of at least 50 hours being required in the aerobic digestion vessels. A residual biorefractory COD of approximately 3,600mg/L was identified which could not be removed by biological treatment. When operating continuously, the biological process was observed to metabolically neutralise the pH 3.0 - 4.5 feed from the chemical flocculation system to pH > 7.0 without the need for supplemental addition of neutralising agents such as sodium hydroxide. This in itself provides a significant economic incentive for implementation of the process. Kinetic analysis of the biological process carried out under controlled laboratory conditions using a Bioflo 3000 continuous fermentor showed that the bio-chemical process followed substrate inhibition kinetics. An appropriate kinetic model was identified to represent the behaviour of the substrate degradation system, and modified by inclusion of a pseudo toxic concentration to account for the effect of pH inhibition upon the biological growth rate. The process was verified both at pilot plant scale and at demonstration plant scale at an operational wool scour. The demonstration plant was of sufficient size to handle the full heavy effluent flow-down from a small wool scour. At the time of publishing three full-scale effluent treatment systems based on this research had been sold to both domestic and international clients of ADM Group Ltd. who funded the research.
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Ibrahim, A. A. "Scour around pipeline under marine environments." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371255.
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Wong, Wai Yin. "The suitability of a rotating fluidised bed (RFB) for incineration and gasification." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370081.
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Kerpicci, Kara Sibel. "Reliability-based Analysis Of Time-dependent Scouring At Bridge Abutments." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610334/index.pdf.
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Deterministic scour prediction equations for bridge abutments do not involve uncertainties coming from scouring parameters and they only consider effects of hydraulic parameters. However, in order to safely design bridge abutments, treatment of these uncertainties and evaluation of possible risks are required. Two artificial neural network (ANN) models are constructed to describe scouring phenomenon using the parameters of two different equations. The equation to be used in the reliability analysis is then determined according to ANN modeling results. To conduct reliability analysis, Monte Carlo simulation technique is used in which different distributions and coefficients of variations are used for random variables to examine their effects on reliability. It is observed that probability distributions of governing variables have no impact on reliability. However, coefficients of
variations of these variables influence reliability.
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Tregnaghi, Matteo. "Local scouring at bed sills under steady and unsteady conditions." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425036.
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Designers are often required to produce safe and economic structures in rivers with erodible beds, which may frequently induce scouring phenomena as they interfere with the natural stream. In CHAPTER 1, an extensive literature is illustrated on scouring by jets at high and low head structures, and predictive formulae are discussed that estimate the equilibrium scour depth of the scour hole, which are most obtained empirically from field and laboratory data. It is also discussed that different stages occur during local scour development. These stages basically include an initial rapid phase of severe scouring, followed by a stabilization phase approaching equilibrium conditions after a long time.
CHAPTER 2 describes the theoretical basis to deal with long-term local scouring at bed sills under clear-water and steady-flow conditions. In gravel bed rivers, bed sills are used to limit bed degradation. Local scouring takes place downstream of each sill in addition to the general erosion pattern, and scour hole dimensions increase with the distance between sills. While overall aggradation can be estimated by using 1D morphological models, local scouring requires a more empirical approach. In fact most scouring phenomena are induced by turbulent jets that diffuse within the scour hole, by resulting in extremely complex flow fields. Many approaches are fully empirical, being based on curve fitting of experimental data that link scour depth to hydraulic quantities and sediment properties. In the most recent attempts, a semi-empirical approach has been followed, based on the identification of appropriate dimensionless groups using dimensional analysis before employing best-fitting procedures. The theoretical derivations proposed, which are based on the assumptions of the Buckingham's ?-theorem, are discussed by showing some further insights on the nature and role of the dimensionless parameters that ensued form dimensional analysis.
CHAPTER 3 presents the results of experimental tests carried out by the author in 2003 about the pattern of local scouring generated at the toe of bed sills. The aim of this study is to evaluate the effect of upstream sediment supply on the scour depth and shape. The experiments simulated conditions of a steady upstream sediment supply which had the same grain size composition as the sediment deposit placed on the bed of the flume. The geometric characteristics of three scour holes developed under conditions of steady-flow discharge and steady upstream sediment supply were measured during 48 different tests. It is shown that the imposed sediment transport does not require the introduction of new dimensionless parameters into existing scour depth and length prediction formulae. The effects of sediment feed are shown to be incorporated in the existing dimensionless parameters. The new data set is used to re-calibrate existing scour depth formula. The influence of jet erosion on scour geometry is also discussed.
Most research efforts have focused on predicting scour depth, which may affect the structure at the free overfall, as opposed to volumetric scour dimensions and sediment yield contribution due to local scour, which may affect downstream morphology and water quality as well as the structure but are much more difficult to measure in an actively eroding plunge pool. In CHAPTER 4, shape and volume of equilibrium local scour holes at bed sills in high-gradient streams are investigated by analyzing steady-flow scour profiles at the equilibrium stage. Geometric properties of the scour profile are analytically discussed and verified on the basis of new data from experimental tests described in CHAPTER 3 and data from literature. A model is presented to organize data analysis into a conceptual frame, which is based on the formal relationships for scour depth and length ensued from dimensional analysis, and on the assumption that scours exhibit definite geometric properties. Results show evidence of a universal geometric affinity of the scour. Geometric similarity is also found to occur, but only in a limited range of physical conditions. Prediction formulae are proposed which link the eroded volume to the geometric, hydraulic and sediment properties. Evidence on the scaling nature of the scour hole shapes have important implications on the prediction of the eroded volume. In turn, a correct evaluation of the eroded volume is necessary for the optimization of the design of the inter-sill distance.
The temporal development of clear-water local scour depth at bed sills in uniform gravel beds is considered in CHAPTER 5. A new experimental program has been carried out by the author, which started at the end of 2006 and was concluded in March 2007 at the Fluid Dynamics Laboratory of The University of Auckland (NZ). Experiments are presented on the development of scour holes under unsteady hydraulic conditions, with the triangular-shaped hydrographs tested being of different durations and different rates of flow variation. Preliminary observations are discussed on the behavior of scour development, which is compared with the scour evolution for the steady-state case. Based on the experimental results and a theoretical framework, a method is given for the definition and prediction of the scouring process under unsteady flows in terms of a dimensionless temporal parameter. A "flash flood" is defined as an event for which the scour doesn't attain its potential magnitude, i.e. the equilibrium value for the peak hydrograph flow rate. It is shown that this flood nature is dependent on both the characteristics of the flood event itself and the characteristics of the stream. A quantitative measure of what constitutes a flash flood is given in terms of the identified temporal parameter, which represents one of the main goal of this study.
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Rapakgadi, Jim. "Detection of contaminants in wool bales using nuclear techniques." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/993.
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To improve the quality and the marketability of wool and mohair, it is important to encourage, ensure and preferable certify that the baled fibre is free of contaminants. Anything other than the fibre that is within the bale can be classified as contaminants; this may be in the form of metal and wooden objects, plastic materials, paints, and vegetable matter such as grass and seed. The internationally accepted method for detecting and classifying these contaminants are highly labour intensive and costly. The ultimate goal of the present research is to develop a non-invasive and nondestructive technique that can be used to detect contaminants, particularly plastic (polymer) materials within wool and mohair bales. Such a technique can be implemented in the wool industry and also could be applied to other fibres, such as cotton. The immediate objective of this study was to evaluate the capability and the limitation of X-rays as a technique to detect such contaminants. It was found that X-rays were suitable for detecting foreign objects, or contaminants, such as metals, but not for detecting plastic materials, such as polypropylene and polyethylene.
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Lim, S. Y. "Scour and particle diffusion caused by water jets." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356261.
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Setipa, Tsepang Benjamine. "Investigating the benefits of establishing a wool scouring plant in Lesotho." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/20428.
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Lesotho’s current production of raw wool is sold to global markets through South African wool merchants. Lesotho does not have any wool processing facilities and as such, the wool from Lesotho gets processed in South Africa or sold to international markets like China where it is processed. Since 2012, the government of Lesotho has publicly showed interest in developing a wool scouring plant that would process locally produced wool instead of selling it in its raw unprocessed form to international markets. The understanding by the Lesotho government was underpinned by perceived economic benefits that could be realised by the country and the wool industry of Lesotho, if the wool scouring plant was developed. The wool industry is important to the economy of Lesotho and as such, wool production in Lesotho contributes to the living standards in the rural areas as their lives are highly depended on the production of wool. A vibrant wool industry in Lesotho therefore has the potential to contribute to the growth of the economy, the manufacturing sector, employment at both the herder and the manufacturing levels, and the export sector. Wool scouring or wool washing is the early stage processing of greasy wool. The purpose of wool scouring is to extract grease, dirt, unpleasant smell and other foreign matter from the greasy wool. Raw wool fibers contain fat, suint (sheep sweat salts), plant material and minerals. It is therefore necessary to remove these from wool by scouring with a combination of detergents, wetting agents and emulsifiers before further processing. Wool can lose up to 30% of its original weight during this process. The Lesotho government feels that there is a need to develop a wool scouring plant in Lesotho because Lesotho does not benefit from the South African wool scouring processes and anything that happens post that process. Given that no viability studies had been conducted in Lesotho to motivate the government’s interest in developing a wool scouring plant, this study was conducted with the aim to investigate the benefits of developing a wool scouring plant in Lesotho. The research design employed in this study was a mixed method, which is a combination of positivism (quantitative) and interpretivism (qualitative) data collection and analysis in parallel form. In terms of the qualitative component of the study, structured interviews were conducted, governed by in-depth interview guidelines developed by the researcher. A questionnaire was used for the qualitative component of the study. Among some of its findings and recommendations the study recommends that there is insufficient wool produced in Lesotho to support a local wool scouring plant, the government of Lesotho should rather focus their effort on the improvement of the wool production value chain to assist farmers. The study finds no grounds for the justification of the development of a local scouring plant in Lesotho and recommends that for such propositions to be made publicly, at least proper groundwork should be undertaken to investigate the technical feasibility of developing the scouring plant.
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Welzel, Mario [Verfasser]. "Wave-current-induced scouring processes around complex offshore structures / Mario Welzel." Hannover : Gottfried Wilhelm Leibniz Universität, 2021. http://d-nb.info/1239419627/34.
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Kouchakzadeh, Salah. "The local scouring phenomenon at bridge abutments terminating in the floodplain zone." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/9915.
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This study examines the local scouring phenomenon associated with bridge abutments exposed to combined main-channel (MC) and floodplain (FP) flows. The principal goal of the study was to develop and validate, based on a comprehensive physical-model testing programme that considered different abutment shapes, an improved relationship for predicting maximum scour depth. A relationship was established among sediment size, flow depth and longitudinal channel slope for initiating the threshold condition of bed material movement. This relationship facilitated the selection of sediment size and channel bed slope for the various experiments, which were performed in a compound channel under interacting (combined MC and FP flows) and non-interacting (isolated FP flow) conditions. Clear-water approach-flow conditions were utilized throughout the testing programme. A flow visualization technique was employed to study the various patterns of the combining flows in the MC/FP junction regions. It determined both the flow deflection angle and the extent of the influence zone (a portion of the channel width beyond the abutment) whose discharge, $Q\sb{w}$, contributes to the scour development. Maximum scour depths produced under interacting conditions were observed to be 15% to 30% greater than those observed for non-interacting conditions. This important observation clearly demonstrated the need to properly account for compound-channel effects in the simulation exercise. The scour prediction relationship presented herein is based on a dimensional analysis of the relevant parameters and incorporates the data obtained from the laboratory studies performed in a compound channel using vertical-wall, wing-wall, semi-circular, and spill-through abutment shapes. The model indicates a very good agreement between predicted and observed maximum scour depths for bridge abutments terminating in the FP zone.
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Munteanu, Adrian. "Scouring around a cylindrical bridge pier under partially ice-covered flow condition." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26722.
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This thesis reports on the first step of an ongoing study of scouring around a cylindrical bridge pier under ice-cover conditions. Previous research confirmed that sediment transport decreases in ice-covered flow compared to free-surface flow. However, most of that research was conducted in a flow depth adjustment condition, maintaining constant the energy slope for both the ice-covered and the free-surface flow. This represents a valid hypothesis when an appropriate length scale is considered (i.e. long river reaches), but numerous other phenomena must be analyzed at a much shorter length scale: i.e. river reaches that contain abutments, bridge piers, cross-section alterations, tide bends, etc. According to Zabilansky et al. (1996--2002) findings, in these cases we can confirm that for an ice-covered flow in nature it is common to adjust faster the energy slope than the flow depth, thus, leading to drastic changes in the sediment transport and scouring behaviour.
From a scouring point of view, when the flow depth has minor variations compared to the energy slope changes, the presence of an ice-cover significantly increases the flow velocities in the bottom half of the flow depth. As a result, a larger part of the flow energy is directed to the scouring process compared to the free-surface case. (Abstract shortened by UMI.)
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Lyons, Simone. "An investigation into the initiation of local scouring around rectangular """"long"""" contractions." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/5029.
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Al-Nassiri, A. M. S. H. "Scour downstream of rock-lined stilling basins." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380040.
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George, Beth, and b. george@curtin edu au. "Scouring the Thin City: an investigation into Perth through the medium of mapping." RMIT University. Architecture and Design, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091006.103921.
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Perth, Western Australia - a city become region one hundred kilometres in length and expanding yet - is a place variously adored and scorned; one noted widely for its landscape and its horizon, and relatively rarely for its architecture. Young, low lying, and sparsely lined with built form, Perth might be described as a thin city. The intent of this research is to entreat an optimistic and inquisitive reading of the city of Perth through the conceptualisation of a set of six narrative threads. Six fictive interpretations of Perth, each denoting qualities of thinness, are cast toward the factual city, inviting both confirmation and opposition to their themes. They are: private city, wide city, even city, city of the immediate future, reserve city and city of form fixation. The process of elucidating and questioning the presence of these narratives allows for thicknesses to emerge from the city region; latencies with which the city can be redressed. The mechanism for directing this interpretive view of the city is the process of mapping. Each narrative thread has been explored through the formulation of a set of maps as a visual text. Through the paired workings of the narratives and the mappings, opportune conditions and operations are uncovered within the thin city, complexities that belie the ubiquity of its surface. Mappings shift in scope from the scale of the region to a site of richness at its core, sampling out entities, structures and performative processes at work in the city's plan, distilling opportune sites that are then explored via the architectural project. At once analytical and synthetic, mappings identify existing points of intrigue and simultaneously invite their extrapolation. With the thin city narratives driving the content of the maps and forming the basis for their projectual exploration, this research seeks to engage with the nascent city and offer to it an armature for its amplification that operates within the city's delirium, its peculiarity, its distinctiveness.
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Hersberger, Daniel S. "Wall roughness effects on flow and scouring in curved channels with gravel bed /." Lausanne, 2002. http://library.epfl.ch/theses/?display=detail&nr=2632.
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Thèse sciences techniques, EPF Lausanne, no 2632 (2002), Faculté Environnement naturel, architectural et construit ENAC, Domaine du génie civil. Directeur: A. Schleiss ; rapporteurs: M. Altinakar, G.-R. Bezzola, J. Gessler.
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Brun, Soren Erik. "Sequential scouring, alternating patterns of erosion and deposition, laboratory experiments and mathematical modelling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0001/NQ35117.pdf.
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Charles, (nee Lapsirikul) Wipa. "Anaerobic bioflocculation as a mechanism for the removal of grease from wool scouring effluent." Thesis, Charles (nee Lapsirikul), Wipa (1994) Anaerobic bioflocculation as a mechanism for the removal of grease from wool scouring effluent. PhD thesis, Murdoch University, 1994. https://researchrepository.murdoch.edu.au/id/eprint/39184/.
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Effluent produced by the wool scouring process is highly polluted with emulsified grease, dirt particles, salts, and detergent. The major problem in treating this waste stream is the wool grease which is resistance to biodegradation. The removal of grease from the effluent would lead to a more readily degradable waste stream, and therefore suitable for further biological treatment processes. This study aimed to investigate anaerobic destabilisation (flocculation), rather than degradation, of wool grease emulsion from wool scouring effluent (WSE). The process therefore can serve as a pretreatment step, prior to a conventional biological process.
The results from this study show that emulsified wool grease in WSE could be removed by bioflocculation under anaerobic conditions. After 110 days of continuous operation, a two-stage anaerobic process treating a high grease (> 10 g/L) effluent removed 70 to 90% grease and approximately 60 to 86% COD at a combined hydraulic residence time (HRT) of 4 to 10 days. With low grease (<10 g/L) effluent grease removal was reduced. At a HRT of 3 days a single stage anaerobic process removed 40 and 44% grease (37 and 43% COD) at 20 °C and 37 °C respectively. Since the supernatant of the treated effluent still contained residual grease of over 1.5 g/L, further purification was necessary. The supernatant was readily treated by an aerobic activated sludge process, reducing the grease concentration from about 1.5 g/L to less than 0.1 g/L, in the final effluent, with an HRT of 3 days.
Methane production and volatile fatty acids consumption of both the above anaerobic systems were negligible. The majority of the grease was removed by flocculation as a result of anaerobic bacterial activity. The mechanisms of this process were investigated by a series of batch experiments. It was found that: (1) appropriate gentle mixing between wool scouring effluent (WSE) and anaerobic sludge resulted in the absorption of wool grease from the liquid phase to the sludge phase, (2) further estabilisation of the wool grease emulsion was obtained when the mixed liquor is left undisturbed. The process thus required a short gentle mixing period of approximately 15 minutes to enable complete contact between the sludge and WSE, and a longer settling period of 2 to 4 days to provide appropriate time for the microbes to destabilise wool grease emulsion and transfer it to the sludge phase.
The process of destabilising the wool grease from wool scouring liquor was found to result from the activities of suspended microbes in the anaerobic sludge, which could successfully grow in WSE, rather than the bulk biomass as required in a conventional anaerobic digestion process. General microscopic observation indicated that during the process of bioflocculation a large number of mixed bacterial cells (> 1Q8 cells/nil) were present in the supernatant and only a small number appeared within the flocculated grease. No evidence of bacterial cell aggregation was observed in the process. It was hypothesised that the mechanism involved the partial degradation of detergent.
Detergent analysis revealed that anaerobic microbes' (taken from the sludge of a municipal wastewater treatment plant) had an ability to partially degrade non-ionic surfactants (nonylphenol polyethoxylates - NPEO) by shortening the hydrophilic ethoxylate chain, resulting in the reduction of surfactant properties. This is likely to be one factor causing coagulation and subsequent flocculation of wool grease in the liquor. Other factors such as production of biopolymers and enzymes by microbes may also play a role, and should be further investigated as they beyond the scope of this thesis.
Ten different bacteria strains were isolated from the supernatant of successfully flocculated WSE samples. Six strains were found to grow in raw WSE as a pure culture. Only three strains caused some flocculation of wool grease, although the reduction of grease from the supernatant was not as effective (20-30%) as that using the mixed culture (60-80%). However, the results were not reproducible when different WSE samples were used, thus no definite conclusions could be obtained from this experiment.
The efficiency of anaerobic bioflocculation was found to vary greatly (30% to 80% grease removal) depending on the source of wool scouring effluent The concentration of bacterial substrate, grease and free detergent (rather than total detergent) were all found to effect the efficiency of the process. At a constant loading rate, the efficiency of the process was found to increase with increased grease concentration in WSE. A rationalisation of the scouring process to minimise detergent use and produce higher concentration grease and suint WSE is a likely benefit of bioflocculation process. These findings lead to the recommendation of a proposed treatment scheme.
The main conclusion drawn from this study is that the anaerobic biological removal of wool grease in WSE is due to the destabilisation of the wool grease emulsion resulting in grease flocculation. Since the process does not require further additives, such as chemical flocculant or oxygen, the removal of the bulk of the grease by simple anaerobic bioflocculation appears to be a useful part of an economic treatment system.
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Poole, Andrew James. "Biological treatment of highly polluted industrial effluent: With application to the wool scouring industry." Thesis, Poole, Andrew James (1999) Biological treatment of highly polluted industrial effluent: With application to the wool scouring industry. PhD thesis, Murdoch University, 1999. https://researchrepository.murdoch.edu.au/id/eprint/52751/.
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The effluent from the scouring of raw wool is the most polluted in the textile processing industry. It consists of a stable emulsion of wool wax in an aqueous medium containing dissolved organic and inorganic pollutants. The typical concentration of solvent extractable material is 9000 mg/L with a chemical oxygen demand (COD) of 30000 mg/L. The effective treatment of this effluent is necessary to ensure the future environmental and economic sustainability of the wool industry, however the effluent has so far eluded any universally acceptable means of treatment.
This study investigates two new biological approaches to treating wool scouring effluent. In accord with the contemporary trend toward treatment processes consisting of several unit processes, the biological systems studied were designed to form part of an overall combined technologies treatment package.
The first process biologically destabilises the wax emulsion, which allows the solvent extractable material to be recovered by centrifugation, whilst simultaneously degrading the biodegradable soluble pollutants. Aerobic continuous culture treatments achieved a 90% decrease in COD with over 99% removal of solvent extractable material. Retention times of less than 40 h were used with both laboratory scale (1.4 L) and pilot scale (100 L) reactors which operated without sludge recycle. A spadable sludge was produced which was approximately 22% by volume of the effluent. The removal of COD occurred non-stoichiometrically, requiring only one third of the amount of oxygen which would have been required by a conventional aerobic biological system. Emulsion destabilisation occurred partly due to degradation of the detergent used to stabilise the emulsion. However about 40% of destabilisation occurred before substantial degradation was shown in an initial destabilisation phase which corresponded to cleavage of the wool wax esters.
The second process complements a chemical flocculation procedure known as Sirolan CF. The Sirolan CF process removes virtually all of the wool wax and other insoluble material from the aqueous effluent to form a sparable sludge. However the soluble organic compounds are not removed and so the aqueous effluent retains 25% of the original COD and requires further treatment.
In this study, a survey to characterize the Sirolan CF effluent was conducted over a six month period and found the effluent had a high organic load with a COD of 5750 mg/L and a low biochemical oxygen demand (BOD5)/COD ratio of 0.29. Aerobic biological treatment was found to remove up to 65% of the COD and essentially all BOD5, detergent activity, and solvent extractable material. The corresponding growth yield coefficient was 0.5 to 0.75 mg biomass produced per mg of COD degraded. The treated effluent retained a COD of 2000 mg/L and an ammonia concentration 147 mg/L, which has a theoretical oxygen demand of 553 mg/L and necessitates discharge of the treated effluent to sewer. Continuous culture treatments used laboratory scale (3 L) and pilot scale (100 L and 3000 L) reactors without sludge recycle. It was found that retention times of about two days would be required for a full scale system due to the high oxygen demand of the effluent. The Sirolan CF process coupled with biological treatment gave a theoretical total COD removal of over 90% with essentially complete removal of solvent extractable material from the aqueous effluent.
The successful operation of both the microbial destabilisation and Sirolan CF effluent treatment processes at pilot scale indicated that they could be successfully developed into full scale processes and used industrially. Both processes offer a high degree of treatment, and are suitable to be integrated into combined technology treatment processes for the treatment of this highly polluted wastewater.
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Eden, David Jason. "Ice scouring as a geologic agent, Pleistocene examples from Scarborough Bluffs and a numerical model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/MQ53460.pdf.
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Rahman, Md Munsur. "STUDIES ON DEFORMATION PROCESS OF MEANDERING CHANNELS AND LOCAL SCOURING AROUND SPUR-DIKE-LIKE STRUCTURES." Kyoto University, 1999. http://hdl.handle.net/2433/181778.
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Melito, Gian Marco. "Analysis, modelling and design of a groin as coastal protection structure at Lido di Dante, Ravenna." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14318/.
Full textAbstract:
An analysis and a subsequent solution is here presented. This document is about a groin design able to contrast the erosion actions given by waves in Lido di Dante. Advantages will be visible also for Fiumi Uniti's inlet, in the north side of the shoreline. Beach future progression and growth will be subjected to monitoring actions in the years after groin construction. The resulting effects of the design will have a positive impact not only on the local fauna and environment, but also, a naturalistic appeal will increase making new type of tourists coming not only for recreational purposes. The design phase is focused on possible design alternatives and their features. Particular interest is given to scouring phenomena all around the groin after its construction. Groin effects will impact not only on its south side, instead they will cause an intense erosion process on the downdrift front. Here, many fishing hut would be in danger, thus a beach revetment structure is needed to avoid any future criticality. In addiction, a numerical model based on a generalized shoreline change numerical model, also known as GENESIS, has been applied to the study area in order to perform a simplistic analysis of the shoreline and its future morphology. Critical zones are visible in proximity of the Fiumi Uniti's river inlet, where currents from the sea and the river itself start the erosion process that is affecting Lido di Dante since mid '80s, or even before. The model is affected by several assumptions that make results not to be interpreted as a real future trend of the shore. Instead the model allows the user to have a more clear view about critical processes induced by monochromatic inputed waves. In conclusion, the thesis introduce a wide analysis on a complex erosion process that is affecting many shoreline nowadays. A groin design is seen as a hard solution it is considered to be the only means able to decrease the rate of erosion.
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DEVI, GEETA. "SCOURING AROUND A GROUP OF PIERS." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19770.
Full textAbstract:
Scour is caused by the erosive action of flow of water, which erodes and takes away
sediments from the river bed, as well as from the area of bridge piers and abutments. This
process of scour is well-known for its complicated behaviour, and this process becomes
more complex for the group of piers. As per the literature available, scour is a major
contributor for the collapse of the bridge structures. Hence it becomes essential for the
researches to predict the scour depth accurately. To fulfill this necessity, the deep
understanding of the flow-field around the piers and factors affecting the scour depth is
important. Numerous studies are available in the literature on the flow-field and local scour,
but majority of them are focused only on single pier. However, multiple piers are more
common in the bridge designing due to economical and geotechnical considerations.
Engineers across the world are predominately considering single pier characterization for
the group of piers, although all bridge structures are laid on the group of piers. The design
considerations developed for a single pier mostly ignores the most significant group effects
for multiple piers such as: pier sheltering, pier spacing and mutual interference effect. It is
demonstrated by the fact that inadequate research and development for the multiple piers
have been observed. Therefore, it is utmost important to investigate the factors affecting
the multiple piers and develop an equation by considering all the variables for accurate
prediction of scour depth.
The primary aim of this research is to investigate the effect of the pier spacing (Ps) between
the piers and temporal scour development on scour depth and propose a new equation for
scour depth estimation. In order to meet the objectives of this research, detailed
experimental study has been conducted for, single pier, two piers, and three piers. In total,
232 experiments have been carried out for various pier spacing and pier arrangements on
uniformly graded sediment in the Hydraulic Engineering Laboratory of Delhi
Technological University, Delhi, India. Pier arrangements studied in this research are:
single pier, two piers in tandem arrangement, two piers in side-by-side arrangement, two
piers at an angle of 15 and 30 degrees to the direction of flow, three piers in tandem
arrangement, three piers in side-by-side arrangement and three piers in staggered
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arrangement. The instantaneous 3-D velocity measurement is conducted by utilizing
SonTek 16-MHz Micro-ADV (Acoustic Doppler Velocimeter) has been used. For
profoundly understanding and continuous monitoring of scour evolution SeaTek
Ultrasonic ranging system have been used.
The Experimental observations for the temporal scour evolutions and scour hole
development pattern for all the pier arrangements under various pier spacing has been
presented in the graphical and pictorial form. The findings of this research shed light on
the factors that causes scour: pier spacing, flow depth, Froude number, and scour
development pattern. These are all important variables, which needs to consider in order to
accurately predict the maximum scour depth. Results shows that, the flow-field around the
group of piers is much more complex than single pier and pier spacing plays a major role
in the scour depth estimation. The results also exemplify that non-dimensional scour depth
increases with the increase in the Froude number and velocity of flow. The effect of pier
spacing shows that the scour depth increases as the pier spacing increases at a certain Ps
range, then it decreases. Furthermore, two semi empirical equations has been proposed for
the tandem and side-by-side arrangements by using GEP, and the comparison of the
proposed GEP equation with the well-known equation and experimental results shows that
the GEP is better prediction tool for scour depth. Lastly, to evaluate the influence of various
parameters on the scour depth sensitivity analysis has been conducted, and concluded that
pier spacing plays an important role in scour estimation. The findings of this study can be
further used for the evaluation of the research data.
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Liu, Chun-Guo, and 劉醇國. "Effect of Bed Scouring on Riverbank Stability." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/g7xq6t.
Full textAbstract:
碩士國立交通大學
土木工程系所
101
In this study, a movable bed flume was set up. To make the conditions close to the natural rivers, the channel bank was paved with the cohesive material composed of the mixture of silica sand and kaolinite; the channel bed was paved with the noncohesive material of the silica sand. Several experimental cases with various inflows and angles of channel bank were conducted to investigate the influence of bed scouring to the time and distance of bank collapsing. Moreover, this study adopted a 2D Depth-Averaged Model (Hsieh, 2003) with adding bank scouring formula for cohesive material(Arulanandan et al., 1980) and safety factor of cantilever failure formula (Chiang, 2011) to simulate experiment cases. The simulation results were analyzed and compared with measured data.
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Huang, Guo-Liang, and 黃國亮. "Developments and verifications of bridge scouring sensors." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/53748471573885510952.
Full textAbstract:
碩士中原大學
土木工程研究所
102
Bridge scour is the major cause for many bridge failures and damage to piers and abutments. Scour is not easily discernible since it is hidden under the channel flow. Over the years, a number of sensors have been developed for detection of scour depth. Development, testing, and small-scale field implementation of a new and simple type of scour sensor in a flume are described in this study. The proposed sensor uses a MEMS accelerometer and attached to a reed which is fixed on the considered pier. The scour depth detection concept is based on observing the amplitude of acceleration time history whether reached the threshold or not. In addition, the relationship between the fundamental frequency of the pier and the scour depth is also discussed. The fundamental frequency of the pier is obtained from the acceleration time history, acquisition by the accelerometer on the top of the pier, using Hilbert-Huang Transfer (HHT) method. Experiment results demonstrate that the fundamental frequency decreased with increasing the scour depth. Furthermore, the proposed sensor could be used as a water-level indicator, scour depth sensor, and anemometer.
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Chi, Tsai Chin, and 蔡金吉. "Scouring at the head of a vertical wall." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/26575302754759770883.
Full textAbstract:
碩士國立海洋大學
河海工程學系
90
The movable-bed physical models are used to discuss that the bed profile variation and scour at the front area of a vertical wall are tested by regular wave condition. In this study, the three different bed slope are 0、1/10 and 1/20 . The tests result show that the erosion zone take place in halfway between nodes and antinodes under standing wave field, and the center of zone from the vertical wall is about 1/8 wave length in the flat bed test. The accumulation zone occur in the nearby nodes of standing waves and the center point is about 1/4 wave length from the vertical wall. The slope bed have the same results with flat bed. Then, in this test by the different wave condition, the depth of erosion increase with wave height increasing and the equilibrium scour profile are builded in the short time with large wave height. The erosion are not occurred at the toe of a vertical wall.
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Po-ShinHuang and 黃柏勛. "Stability of Reinforced Dykes Subjected to Toe Scouring." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/77406742789910908619.
Full textAbstract:
碩士國立成功大學
土木工程學系
103
SUMMARY The effect of toe scouring on the stability of geosynthetic-reinforced dykes was investigated using model dykes backfilled with an idealized 2-D backfill. In addition, the effect of reinforcement configuration was also investigated. The following conclusions were obtained: 1. The bearing capability against toe scouring and the resistance of backfill against can be significantly improved via the use of geosynthetic reinforcement. By increasing the length of reinforcement, especially for those near the base of the dyke, the above-mentioned effect can be further increased. 2. The bearing capability against toe scouring of the 30° slope reinforced dyke can be enhanced significantly by using a relatively small amount of the reinforcing material, comparing with that needed in the case of a steep-faced (60°) dyke, in order to achieve a similar degree of dyke stability. 3. The effect of soil reinforcement against toe scouring is also influenced by the extend (or size) of toe scouring. Test results show that the contribution of reinforcing materials is more significant in the case of small scale toe scouring than that in the case of large-scale toe scouring.
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Liu, An-Kang, and 劉安剛. "Submerged Panels against Scouring for Bridge Abutment Protection." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/ndx676.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系碩博士班
90
ABSTRACT The objective of this study is to reduce scour depth of abutments for protecting the bridge. To reduce scour around bridge abutments. Direct methods are used in literature, dealing with abutments-scour problems, such as placed rocks, riprap or flexible mattresses around the abutment foundation. This studies an indirect one that examines the effect of using submerged panels around the abutment. Experiments conducted in clear-water conditions. The angle of the panel is 135°, the width of the panel is 63 cm, the distance between panel and abutment equal to 0 cm, depth of panel with the submerged water is 1 cm. They can reduce scour depth as much as 99% in final equilibrium.
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Shih-Hsien, Peng, and 彭思顯. "The Local Scouring Phenomenon of Free Overfall Flow." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/37939767681426637470.
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Kuo, Ding Yuang, and 郭丁元. "Surface Panels against Scouring for Bridge Pier protection." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/39754143473181306523.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系
82
The objective of this study is to reduce scour depth of piers for protecting the bridge. To reduce scour around bridge piers. Direct methods are used in literature,in dealing with pier-scour problems,such as streamlined piers, placed a collar around the pier ,placed rocks,riprap or flexible mattresses around the pier foundation. On the ether band,this studies an indirect one that examines the effect of using surface panels at the upstream of pier. Experiments conducted in clear-water conditions show that the use of panels with opening tongue shake ( with the width of panel equal to the pier diameter ) The angle between panel and panel is 60 ,the distance between panel and pier equal to 2~3 time of the pier diameter, the oncoming distance between panel and panel equal to 0.1~0.25 times of the pier diameter, depth of panel with the to submerged water is 0.6~0.8 time times flow depth. They can reduce scour depth as much as 86%~89% in final equilibrium. These devices may also be uses in the problem of local scour-deposition in bydraulic engineering.
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CHAUHAN, KAUSTUBH. "CFD STUDIES OF LOCAL SCOURING AROUND BRIDGE PIER." Thesis, 2019. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16836.
Full textAbstract:
The threat of local scour around bridge piers has been in research for many years. According to the various studies, local scour around the bridge pier is the prime cause for most of the bridge failures. The main objective of the present study was to investigate the flow behavior and the scour phenomenon around the bridge piers of various shapes namely Circular, Elliptical, Square and Streamlined. Local scouring depends on various factors like depth of flow, upstream flow conditions, pier shape and dimensions. Here, we have taken only pier shape as the primary factor and kept other factors constant. The numerical simulations were even carried out using CFD- Fluent, eulerian, k–epsilon turbulence model, to elaborate the physics behind the scour formation. CFD simulation tool can be used for wide understanding of the flow behavior around the bridge piers even without physical model studies because it saves time and money as compared to experimental studies. Three dimensional simulation of flow behavior around four pier shapes indicates that the streamlined pier is the most efficient pier to use as it allows the flow to pass smoothly around it creating less obstruction to the flow and hence creating less chances of local scouring near the pier toe.
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Simpson, Alison Elizabeth. "The recovery of sodium hydroxide from cotton scouring effluents." Thesis, 1994. http://hdl.handle.net/10413/9111.
Full textAbstract:
This dissertation describes the characterisation of, and development of a novel integrated waste
management strategy for, hydroxide scouring effluents produced during cotton processing. Such
effluents are typical of mineral salt-rich waste waters which are not significantly biodegradable in
conventional treatment plants. The proposed strategy focuses on two complementary concepts:
process-oriented waste minimisation adopts a systematic approach to identifying potential
problems and solutions of waste reduction in the manufacturing process itself; while add-on controls
reduce the impact of the waste after it has been generated, by recycling and treatment.
The basic procedures for ensuring effective water and chemical management within the scouring
process are described. Examples are given of factory surveys, which have resulted in significant
chemical and water savings, reduced effluent discharge costs, maximum effluent concentration, and
minimum pollutant loading and volume.
Pilot-plant investigations demonstrate the technical and economic feasibility of a four stage treatment
sequence of neutralisation (using carbon dioxide gas), cross-flow microfiltration, nanofiltration and
electrochemical recovery to remove colour and impurities from the scouring effluent and produce directly
reusable sodium hydroxide and water. Fouling and scaling of the cross-flow microfiltration, nanofiltration
and electrochemical membranes are minimal and reversible if the operation is carried out under carefully
selected conditions. A long anode coating life is predicted. Current efficiencies for the recovery of
sodium hydroxide (up to 20 % concentration) are 70 to 80 % and the electrical power requirements are
3 500 to 4 000 kWh/tonne of 100 % NaOH.
Pilot-plant trials are supplemented by extensive laboratory tests and semi-quantitative modelling to
examine specific aspects of the nanofiltration and electrochemical stages in detail. Electromembrane
fouling and cleaning techniques, and other anode materials are evaluated. The effects of solution
speciation chemistry on the performance of the nanofiltration membrane is evaluated using a
combination of speciation and membrane transport modelling and the predicted results are used to
explain observed behaviour.
Based on the results of pilot-plant trials and supplementary laboratory and theoretical work, a detailed
design of an electrochemically-based treatment system and an economic analysis of the electrochemical
recovery system are presented. The effects of rinsing variables, processing temperatures, and
background rinse water concentrations on the plant size requirements and capital costs are determined.
The implementation of the waste management concepts presented in this dissertation will have
significant impact on water and sodium hydroxide consumption (decreasing these by up to 95 and 75 %
respectively), as well as effluent volumes and pollutant loadings.Thesis (Ph.D.)-University of Natal, Durban, 1994.
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Ling-TingHuang and 黃令婷. "Potential of Adverse Effects of Pier Protection on Scouring." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/96493513534802313759.
Full textAbstract:
碩士國立成功大學
土木工程學系碩博士班
98
Bridge to reduce the river cross section through the water, easy caused pier scour exposedness. Therefore the experimental used cone protection collar and small-scale experimental hydraulic models, then investigate the different to cross section through the water to aggravate piers scour of the effects extent. The experimental results of this thesis demonstrates, the protection collar of efficacy can explain that it can completely resist the down flow and the horseshoe vortex and reduce scour depth and will not effect reduced cross section through the river. But pier exposed circumstances and pier base depth insufficient caused have protection collar the bridges advance of damage.
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Yan-PingLin and 林晏平. "Submerged CKPB for Scouring Control in the Bend Channel." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/39847307807596283350.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系碩博士班
100
This paper is about protecting the bend channel by Submerged Cheng-Kung Porous Basket (CKPB) in the bend channel. In this paper, we set up Submerged CKPB of the OP’s upstream, and setting parameters to observed the scouring control in the bend. The result tell us the best, Row-Spacing = 8 cm, the Max-depth = 7.65 cm, the min-depth = -0.85 cm; Ld(A) = 0 cm, the Max-depth = 9.6 cm and the min-depth = 2.6 cm; Ld(B) = 0 cm, the Max-depth = 8.3 cm and Ld(B) = 2 cm, the min-depth = 3.2 cm; L(C) = 2 cm, the Max-depth = 8.3 cm, L(C) = 6 cm or 8 cm, the min-depth = 2.6 cm; Deg(A_1 B_2) = 30∘, the Max-depth = 7.75 cm, and Deg(A_1 B_2) = 60∘, the min-depth = 1.6 cm; Deg(C_4) = 90∘,the Max-depth = 9.2 cm, the min-depth = 2.6 cm. the protection for scouring control in the bend channel is excellent.
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Fan, Wen-Kang, and 范文綱. "A local Scouring Monitoring and Safety Warning System of Bridge." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/e8exwg.
Full textAbstract:
碩士國立中央大學
土木工程研究所
97
Scour is always the primary threat to bridges in Taiwan area. Since bridges will experience floods which may cause damage from scour holes forming around bridge piers and abutments. As scour changes the geometry of the bridge pier embedded in the soil foundation, the effects due to other loads, such as live load, wind load, debris collision, etc., are amplified. In this condition, bridge may have settlement or tipping even collapse. Therefore it is demanded by the bridge authority agencies to have a monitor sensor to determine the real-time scour depth. Besides, with internet it is easily to handle the real-time information at bridge site to alarm the siren in time from control center through the predefined safety warning algorithm. A piezoelectric fluoropolymer film type real-time scouring monitoring sensor installed along the bridge pier is presented. The core idea of developing this scouring sensing system is based on the physical character that output voltage can be generated as the piezoelectric thin film is deformed by the flowing media. Therefore, a sensing device can be manufactured by mounting piezoelectric thin films along the rod with a fixed distance and insert it into a borehole beside the bridge pier. The piezoelectric film embedded in the soil of riverbed is undeformed and the output voltage is much smaller than the one disturbed by the water current. From the output signals of all the piezoelectric sensors with known locations along the depth of the pier foundation, one can trace the variation of the soil/water interface before, during and after a flood. Compared with other types of scouring sensors, this piezoelectric type scouring sensor is working without power, durable, sensitive, real-time and cost effective. In this paper, the basis theory and the performance that in laboratory of this novel piezoelectric film type scouring device are introduced. The installation of the system in field is also addressed. In this study, it also brings up three methods for readers to analyze the safety of bridge, which can be taken into consideration of blocking a bridge.
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Chen, Te-Lung, and 陳德龍. "An Application of Non-touch Measurement on Seabed Scouring Test." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/49679394905643476919.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
92
In this study, a non-touch seabed scouring measurement technique was developed. Combine with laser beams, digital image processing, and coordinate adjustment skill, the device can measure the seabed profile remotely to prevent any disturbance on the seabed. The survey of time-varying topography in a large range can be done by repeating a simple procedure in high resolution and accuracy. From the application of the device on the hydraulic model test of seabed scouring in front of a vertical breakwater during the typhoon wave action period. The time varying of the seabed scouring, the maximum scour depth, location, and needed time was investigated. The results show that the maximum scour depth increase with time, and has no obvious change on its location. The needed time to reach the maximum scour depth is decreased when wave condition getting larger.
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Chiu, Hui-Ping, and 邱惠萍. "Studies the relationship between scouring depth and face slope of." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/59065845454765380655.
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Chen, Yen-You, and 陳彥酉. "Development of a Depth-Averaged Two-Dimensional Pier Scouring Model." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/32767061140556743096.
Full textAbstract:
碩士國立交通大學
土木工程學系
99
This study develops a depth-averaged two-dimensional pier scouring model to simulate both the contraction scour and the local scour properties due to vertical flow. The framework of the model developed is based on the depth-averaged two-dimensional mobile bed model by Hsieh (2003), in which employed the immersed boundary method is to deal with the internal pier boundary. The maximum vertical flow velocity and the corresponding sediment transport formula are taken into account to simulate the local scour phenomenon. The maximum vertical velocity regression formula is established from the velocity field simulated by a commercial 3-D model, CFX, through several hypothetical cases designed. Several bridge pier scouring experiment results are used to conduct the model calibration and parameter regression analysis to develop the empirical formula of local scour. Furthermore, the model is verified by using experiment results other than those for calibration. The verification studies show that the variation of the scour depth with respect to time around the bridge piers could be well simulated.
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Wu, Wen-Ying, and 吳紋瑩. "Laboratory Investigation of Scouring Downstream of Two Grade-Control Structures." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/55277482956629771365.
Full textAbstract:
碩士國立中興大學
土木工程學系所
100
River bed elevations of many rivers in the west of Taiwan have lowered down seriously and caused the exposures of pier foundations for the past few decades. The management bureaus often build grade-control structures to stabilize the river beds and reduce the scouring of pier foundations. There is an urgent need for the research of scouring downstream of grade-control structures. A series of experiment on the grade-control structures was conducted with different sand sizes and slopes for four kinds of flow discharges under steady and unsteady flow conditions. The mechanism of the edge failures downstream of the grade-control structures and the shapes of the scour holes were investigated. Moreover, the evolution of the scouring process was simulated. The scour downstream of the second grade-control structure was considered as a live bed scour due to the upstream sediment supply. In regard to the steady flow scour simulation, the shapes of equilibrium scour holes downstream of the first grade-control structure were analyzed with our measured data and Lu et al.’s (2012) laboratory data for the stepped grade-control structure. For the scour holes downstream of the second grade-control structure, the Froude number was considered as an influencing factor. Also, the model was compared with Gaudio and Marion’s (2003) model for subcritical flow in order to increase the practicality of the model. By analyzing experimental data with steady flows, a scheme is proposed to calculate the temporal variation of scour depth with unsteady flows for four different types of scouring hydrograph. In general, the evolution of the scour depth for an unsteady flow can be simulated by the superposition of the simulated scour evolution curves for the steady flows. The temporal variation of scour depth during the typhoon-induced floods can be quickly estimated based on the proposed scheme.
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尤俊傑. "Preliminary study on Effects of scouring on pile Foundation Performance." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/80634798214097210871.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
101
Taiwan is located between The Philippines plate and The Eurasian plate. Due to orogenesis makes the Central Range of Taiwan becoming long and narrow from north to south. The river distribute east and west. Because Taiwan is located in typhoon area, when typhoon pass through, it makes heavy rainfall. This heavy rainfall often causes deluge, that makes river bed scouring and soil loss . As a result the corssed-river bridges are damaged. Due to the serious erosion problem, the foundation of bridge exposed above the river bed for several meters in all Taiwan rivers. When typhoon or severe thunder storm come , the disasters of broken bridge can not be ignored. In order to understand the situation ,that the flow force applied to on the pile foundation . This study set a different flow velocity (3m / s, 5 m / s and 7 m / s), the river water level (3 m, 5 m, 7 m) and scour depth (1 m, 2 m, 4 m, 7.5 m) total of 36 kinds of situation, and use finite element method (FEM) Plaxis 3D. Finally ,we can know the displacement and stress on pile foundation under the water erosion.
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YU, CHIA YUNG, and 游家勇. "Research on possibility of synthetic fabric scouring in lower temperature." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/6y5w6m.
Full textAbstract:
碩士國立臺北科技大學
有機高分子研究所
105
In the manufacturing process of synthetic fabric, the oil, wax or size are used to increase the smoothness of the yarn and reduce friction. But the oil and size on the fabric are easy to appear the color spots, uneven color and size spots in the dyeing process. So we use scouring agent to remove the oil and size before the dyeing process of the fabric called the scouring process of the fabric. The scouring process of the fabric is applied in high temperature and 1~3 times washing in hot or cold water after scouring to make sure the oil removed is totally. It’s a energy and water consumption process. In this dissertation, the factors in the scouring process of the fabric were studied. According to change the temperature, pH and the time in the scouring process of the fabric and scouring agent were characterized by dosage, foaming and wetting.
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Liu, Stone, and 劉世桐. "An Experimental Study on Scouring Characteristics in front of Inclined Seawall." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/51147050639562387465.
Full textAbstract:
碩士國立海洋大學
河海工程學系碩士在職專班
90
This experimental study was conducted in Department of Harbor and River Engineering of NATIONAL TAIWAN OCEAN UNIVERSITY. Which is aimed to understand the Scouring Characteristics in front of inclined seawall for the special case of normally-incident, regular non-breaking, partially reflected, two dimensional and uni-directional waves. Experimental proceeding combined 3 different inclined slopes （30、45 and 60 degree with horizontal plane, respectively） and 3 different wave propagating conditions （Period T=1.0 sec Wave Height H=5.4cm、T=1.2sec H=6.15cm and T=1.4sec H=5.5cm, respectively）.The results show that： 1. The positions of accretion and scouring of sand-bed are accordant to the node and L/8 both sides nearby node respectively . 2. By dimensional analysis, the non-dimensional factor, and , as the Surf similarity parameter and incident wave parameter, are all have the pattern of direct ratio with reflection coefficient. Which means that the lesser of facial slope the lesser of wave reflection. 3. By dimensional analysis also, the non-dimensional factor, , as the Ursell parameter, have the pattern of direct ratio with scouring depth in front of seawall-toe. Which means that the more of the Ursell parameter the more of scouring depth. 4. A virtual reflection wall, plane vertically through the gravity center of vertical triangle, which is composed by composite wave amplitude and inclined face, was found. The phenomena of virtual reflection wall maybe an important factor which could influence the scouring.
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Chiu, Ming-Hung, and 邱銘鴻. "Experimental Study on Panel Effect to Sand Motion and Local Scouring." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/51415229301365868283.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系
86
The aim of this experiment studies is undertaken to know the directions of sand motion and the positions of local scouring due to the effect of differentflow-training panels. It is known by experiments that the sand motion is caused by helix in a clockwise direction of the angle of attack is smallerthan -π/2, no matter how large the opening of the surface panel. The bottompanels have a critical height is about 0.5 times local water depth at designstage. In other words, the panel''s height is above or under the critical depthof bottom panels, while the sand-training is quite different. The middlepanels, not close to the surface and the bottom, only in the case the panel''s bottom is close to the river bed have the nearby phenomenon of depositing and scouring with the bottom panels. In the same angle of attack with flow, the bottom panels with the height greater than half local water depth at design stage have the same phenomenon of depositing and scouring with the surface panels. The open space under the surface panel allows the flow passing, then the local scour will take place at downstream, but the bottom panel has the local scour at upstream nearby.
46
Fang, Yu-Yun, and 方于芸. "Study on Scouring Rate of Local Scour by Sloping Drop Structure." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/j84t6k.
Full textAbstract:
碩士國立中興大學
土木工程學系所
105
For river management and water acquirement, drop structures are commonly set up in the river course. Although the stream channels can be stabilized, the gravel will not move downwards and its deposition near the drop structures increases the slope of upstream channel, consequently leads to a steep slope and induces fast flow. As a result, the large impact forces destroy the downstream protection work of drop structures. This study aims at the scouring rate of local scour and relevant scouring behavior by sloping drop structure. From the analyzed results, it indicates that (1). The maximum stable scouring depth Yse is proportional to the drop number D, but it is inversely proportional to the dimensionless diameter of bed material G and the bed slope of upstream channel S. The distance from toe to the maximum stable scouring depth Lse and the maximum scour length Lei are proportional to both D and S, but they are inversely proportional to G. The maximum scouring volume per unit width of flow quantity is proportional to the dimensionless impact force F ̅d, but it is inversely proportional to the G and S; (2). The characteristic time te to reach the stability of scour increases with the increase of D and decrease of G, but it is almost indifference to S; (3). The maximum time-dependent scouring depth Yst , scouring distance Lst, scouring length Lit and scouring volume per unit width of flow quantity Ast is proportional to time in an exponential manner, but it is inversely proportional to the G and S; (4). The bed scour is caused by drop nape in a great scouring rate. The souring pit is almost completed in a quarter time of te and the scour will be developed completely when the characteristic time te is arrived.
47
Chang, Pai-Hsin, and 張百欣. "Effect on surface roughness to toe scouring of a slope seawall." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/53347211122694925894.
Full textAbstract:
碩士國立中興大學
土木工程學系
84
ABSTRACT The variation of the toe scours profile by the surface roughness of a slope seawall was investigated experimentally in this research. The effects of the roughness on the wave characteristics, including the wave run-up on the slope, the flow in the down-rushing wave and the wave reflection from the wall, are also explored. Two types of the toe scours, named the L-type and N-type, were performed in the experiments. It was found from the experiments that the surface roughness was potentially reducing the intensity of the down- rushing flow and the wave run-up height, even the reflection of wave. The maximum depth of the scours as well as the scouring distance was thus reduced in the light of the surface roughness. The scouring depth and the values of the wave characteristics on the slope were descended obviously due to the surface roughness, from comparing with the smooth surface. However,these descended values were limitedly increased as the surface roughness became larger.
48
Jan, Yuan-Haur, and 詹元豪. "Local Scouring to Single Pile and Pile Groups of Bridge Pier." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/79241168101427856530.
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49
Chang, Hui-Cheng, and 張惠成. "A Study of Modeling Processes of Fluvial Scouring and Sediment Transport." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/64675970343004268398.
Full textAbstract:
碩士國立中興大學
土木工程學系所
104
Fluvial sedimentation and riverbed scour are crucial issues in Taiwan. In recent years, Taiwan has frequently influenced by climate change and heavy rains, resulted in serious fluvial scour problems. In general, mud has usually silted up in the upstream of main channel. And local scours are also occurred in midstream and downstream of river. Maximum scouring particularly happens at the location around bridge or span of channels. Fluvial disasters happened frequent in Dajia River in the past few years. Including downstream side of Shihgang Dam, Pifeng Bridge, New and Old Mountain Railway Bridge and Houfeng Bridge all have severe problems of riverbed scour or batholith bared. In order to study this issue, this study used WASH123D numerical model with local empirical formula to model fluvial sedimentation and riverbed scour of Dajia river. Scenarios of removing Shihgang Dam and dredging channel at specific cross sections are examined to discuss in this study. Simulated results have showed a reasonable performance on the stages of model calibration and validation. It indicated that the wave propagation of water flow is slightly faster than sedimentation transport in Dajia river. Time difference is exaggerated accompany with flow travels to downstream. For the scenario of Shihgang dam removed, simulation showed that the riverbed scours have extended toward upstream until Dongshi Bridge. For the downstream site, however, the riverbed scours from original site of Shihgang Dam to Houfeng Bridge are eased. Simulation also founded that the sedimentation transport is getting faster as dam removed in the scenarios of Q20 and Q50. But Q100 shows no apparently difference. For the cases of dredging channel on Meizi Iron Bridge (CS43-1) and CS35-1, it revealed very slightly influenced on riverbed scour and sedimentation concentration. But flow pattern and flow direction have significant improvement to ease erosion to left bank of above two site. It indicated that dredging riverbed can ease local erosion, and not cause sharp impacts on local maximum riverbed scour and sedimentation concentration.
50
WU, CHENG-YE, and 吳承燁. "Study on Simulation of Flow Field and Scouring Depth in River." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/95094377246430922992.
Full textAbstract:
碩士高苑科技大學
土木工程研究所
105
Taiwan is a narrow island, affected by topography and climatic factors, the slope of the river is very steep and the scouring of the riverbed is quite serious.It will make scour on bridge piers and will make bridge damage, the impact of transportation is very large. In this study, two-dimensional flow field was simulated by SMS for Laiser river and Checheng bridge of Pingtung County in Southern Taiwan. Simulation of scour depth and main deep trough change can verify the accuracy by the flow field. It can also provide references for related projects. In this study, simulation setup 200m length right bank and 30m*15m wave-breakers apron of Checheng Bridge to protect P1 and P2 piers.Simulation results shows that the flow speed reduced from 4m/s to 2.5m/s in right bank，but the flow speed increased from 3.7m/s to 5m/s in left bank. We can reduce the flow speed from 5m/s to 3.5m/s by adding 30*10m wave-breakers apron in left bank.