Tesi sul tema "Hydrodynamic efficiency"
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Teixeira, E. C. "Hydrodynamic processes and hydraulic efficiency of chlorine contact units". Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495625.
Testo completoMcLetchie, Karl-Magnus Weidmann. "Force and hydrodynamic efficiency measurements of a three-dimensional flapping foil". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33437.
Testo completoIncludes bibliographical references (p. 69-70).
Investigations into unsteady flapping foil propulsion have shown that it is an efficient and high thrust means of propulsion. Extensive work has been done to optimize the efficiency of two-dimensional flapping foils, varying both the kinematics of the motion and the flexibility of the foil. However, no thorough investigation into the hydrodynamic efficiency of three-dimensional flapping foils has been made. In this thesis, experimental hydrodynamic efficiency measurements and force measurements of a three-dimensional flapping foil are presented. These measurements were made by mounting a small, six-axis dynamometer directly onto the foil shaft of a flapping foil module. The module uses two computer controlled servo motors to actuate a foil in a sinusoidal pitch and roll motion, similar to the motion of a penguin's wing. The measured thrust coefficients compared well to previous experimental results, and the on-shaft dynamometer proved to be a valuable sensor. However, the experimental apparatus must be modified before reliable efficiency results can be made for the entire range of kinematics.
(cont.) Once these improvements are made, a thorough investigation into the effects of foil geometry and flexibility can be done to find the optimum efficiency parameters of a three-dimensional flapping foil. These optimum efficiency parameters will be valuable for the development of flapping foil vehicles.
by Karl-Magnus Weidmann McLetchie.
S.M.
Potts, John B. III. "Developing and Testing an Anguilliform Robot Swimming with Theoretically High Hydrodynamic Efficiency". ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2103.
Testo completoNguyen, Khanh Quoc. "Hydrodynamic Study of Pisciform Locomotion with a Towed Biolocomotion Emulator". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103626.
Testo completoMaster of Science
It is no surprise that through thousands of years of natural evolution, marine species possess incredible ability to navigate through water. As we expand our presence in the sea, more and more tasks require underwater operations such as ocean exploration, oil-rig maintenance, etc. Yet, most of the underwater robotic vehicles still utilize propellers as the primary propulsive mechanism. In many cases, the bio-inspired propulsion system that mimics the swimming action of fish offers many advantages in agility, maneuverability, and stealth. With the rising interest in the field, the works presented in this thesis aim to expand our understanding of how to implement the bio-inspired propulsive mechanism to robotic design. To achieve this, a mechanical device is designed to mimic the swimming action of different fish species. Then, an experiment is performed to subject the device to different fish-like motions and test their effectiveness. In addition, a reduced-ordered model is also introduced as an alternative method to predict the hydrodynamic performance of this propulsive mechanism. The works presented in this thesis help to expand the toolbox available for the engineer to design the next generation of the underwater robotic vehicle.
Annerstedt, Måns, e Axel Apoy. "Fartförlust på grunt vatten : En jämförelse av bränsleförbrukning och tidsåtgång för rutter med olika djup och distans". Thesis, Linnéuniversitetet, Sjöfartshögskolan (SJÖ), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-43451.
Testo completoThis study concerns the speed loss and thereby the increased energy consumption which affects ships in shallow water. The aim of the study was to gain knowledge of how much shorter a shallow passage is required to be in order to be the better alternative compared to a long and deep route with regard to fuel and time consumption. The result was that it is not possible to draw any definitive conclusions which are applicable to all ship types, however, there are clear patterns. Moreover, the goal of the study was to aid mariners facing a choice between a long and deep route and a short and shallow route, this was done by creating a compilation of the results for speed loss in open water. Due to the results for confined waters being the same for all the ships in the study, no compilation was done for confined waters as it was deemed excessive. The aim of the study was achieved by quantitative research in the form of mathematical models to calculate speed loss, fuel consumption and time consumption for a number of fictitious ships.
Horko, Michael. "CFD optimisation of an oscillating water column wave energy converter". University of Western Australia. School of Mechanical Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0089.
Testo completoLi, Bin. "Efficient water wave and current propagation modelling". Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281589.
Testo completoHinkelmann, Reinhard. "Efficient numerical methods and information-processing techniques for modeling hydro- and environmental systems /". Berlin [u.a.] : Springer, 2005. http://www.loc.gov/catdir/enhancements/fy0663/2004116864-d.html.
Testo completoZvandasara, Tendayi. "Influence of hydrodynamics on carbon steel erosion-corrosion and inhibitor efficiency in simulated oilfield brines". Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2284/.
Testo completoStewart, Kelley Christine. "Quantitative Hydrodynamics Analysis of Left Ventricular Diastolic Dysfunction using Color M-Mode Echocardiography". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35466.
Testo completoMaster of Science
Hamann, Martin Louis. "System hydrodynamics to reduce fouling of air-sparged immersed flat-sheet microfiltration membranes". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5206.
Testo completoENGLISH ABSTRACT: Immersed membrane systems hold many operational and environmental advantages in biological treatment of wastewater. However, immersed membrane filtration have only found application in niche markets to date because of higher capital and operating costs associated with membrane fouling. But with capital costs on the decline as membranes become less expensive, immersed membrane systems are increasingly considered as an attractive alternative to conventional treatment processes. Operating costs remain high however, since energy intensive techniques such as air-sparging are required to limit membrane fouling. Improving the air-scouring efficiency of air-sparged immersed membranes can significantly reduce operating costs and unlock the immersed membrane system technology to wider application. The aim of this study was to identify factors that will improve air-scouring efficiency in order to produce guidelines that will help in the development of an immersed microfiltration membrane system with a resulting lower operating cost. Although, the research was done on a flat-sheet microfiltration membrane, the guidelines obtained can be used for the development of any immersed microfiltration membrane arrangement. An airlift reactor set-up was chosen for this study. Six system hydrodynamic factors were evaluated in a factorial design to determine their effects on the cross-flow velocity profile. They were the downcomer area to riser area ratio, top clearance distance, bottom clearance distance, aeration intensity, water depth and air sparger location. It was found that the air-scouring efficiency was increased by generating a cross-flow velocity profile with increased magnitude and uniformity, but absolute uniformity of the cross-flow velocity profile was found to be a prerequisite for optimisation of air-scouring efficiency. Downcomer area to riser area ratio was found to be 99.9% significant in determining the magnitude of the cross-flow velocity profile. Two models were developed to respectively predict the relative magnitude and uniformity of the cross-flow velocity profile. By using these two models, a methodology was developed to design an airlift reactor set-up that would produce system hydrodynamics with an improved air-scouring efficiency.
AFRIKAANSE OPSOMMING: Gesonke membraanstelsels beskik oor talle bedryfs- en omgewingsvoordele in biologiese behandeling van afvalwater. Maar weens die hoër kapitaal- en bedryfskostes wat gepaardgaan met membraanbevuiling, kon gesonke membraanstelsels tot op hede nog net toepassing in nismarkte vind. Maar soos kapitaalkoste daal met al hoe goedkoper membrane beskikbaar, word gesonke membraanstelsels al hoe aanlokliker as ‘n alternatief vir konvensionele behandelingsprosesse. Bedryfskostes bly egter hoog aangesien energie-intensiewe tegnieke soos lugborreling benodig word om membraanbevuiling te vertraag. Deur die effektiwiteit van die skropaksie wat lugborreling aan gesonke membrane bied te verbeter, kan ‘n beduidende besparing in bedryfskostes teweeggebring word om sodoende die uitgebreide toepassing van gesonke membraanstelsel tegnologie moontlik te maak. Hierdie studie het ten doel gehad die identifisering van faktore wat lugskropaksie effektiwiteit kan verbeter en om riglyne op te stel vir die ontwikkeling van ‘n gesonke mikrofiltrasie membraanstelsel met gevolglik laer bedryfskostes. Alhoewel hierdie navorsing ‘n plat-blad mikrofiltrasie membraan gebruik het, kan die riglyne steeds vir enige gesonke mikrofiltrasie membraanuitleg gebruik word. Daar is besluit op ‘n lugligter-reaktor opstelling vir hierdie studie. Ses stelselhidrodinamika faktore is geëvalueer in ‘n faktoriale ontwerp om hul effekte op die kruisvloei snelheidsprofiel te bepaal. Hulle was die afvloei-area tot opvloei-area verhouding, topruimte-afstand, bodemruimte-afstand, belugtingsintensiteit, waterdiepte en belugterligging. Daar is bevind dat die lugskropaksie effektiwiteit verhoog word wanneer ‘n kruisvloei snelheidsprofiel geskep word met ‘n verhoogde grootte en gelykvormigheid, maar die absolute gelykvormigheid van die kruisvloei snelheidsprofiel is gevind om ‘n voorvereiste te wees vir optimale effektiwiteit. Afvloei-area tot opvloei-area verhouding is gevind om 99.9% beduidend te wees in die bepaling van die snelheidsprofiel se grootte. Twee modelle is ontwikkel om afsonderlik die relatiewe grootte en gelykvormigheid van die kruisvloei snelheidsprofiel te voorspel. Die modelle is in ‘n metodologie vervat vir die ontwerp van ‘n lugligter opstelling met stelselhidrodinamika wat verbeterde lugskropaksie effektiwiteit sal skep.
Chipman, Donovan R. "Two-Dimensional Hydrodynamics of Swimming Rainbow Trout Using Navier-Stokes and Large Eddy Simulation Models". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2671.
Testo completoVan, Houwelingen ArJan. "Liquid-solid contacting in trickle-bed reactors". Thesis, University of Pretoria, 2009. http://hdl.handle.net/2263/30008.
Testo completoThesis (PhD)--University of Pretoria, 2009.
Chemical Engineering
unrestricted
Podal, Pavel. "Studium vlastností katalyzátoru na bázi MnOx s využitím RRDE". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219064.
Testo completoPadrón, Mariana. "Evaluation of conservation efficiency for gorgonian species at a regional scale based on an existing Marine Protected Area network and modeling scenarios accounting for hydrodynamical connectivity". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066652/document.
Testo completoConnectivity is expected to strongly influence the dynamics and persistence of marine populations. Studying the development and maintenance of connectivity patterns among marine populations is, thus, essential for spatial planning and the proper design and management of Marine Protected Areas (MPAs). However, understanding the complex processes driving marine population connectivity requires the use of tools that integrate bio-physical models with information regarding the demographic and genetic linkages resulting from the larval exchange among populations. Therefore, the aim of this PhD dissertation is to evaluate the patterns of genetic connectivity among gorgonian populations at a regional scale, and disentangle the processes that shape the observed connectivity by using model simulations accounting for hydrological, demographic and genetic connectivity. The first chapter presents a spatially explicit metapopulation model that, using stochastic connectivity matrices, assesses the effect of demography on allele frequencies in a marine metapopulation of sessile benthic species. The model is then used to evaluate the effect of demographic traits and connectivity structure on the genetic diversity of a marine metapopulation. The second chapter examines the patterns of genetic connectivity of two common and widely distributed gorgonian species at a regional scale: Paramuricea clavata in the Ligurian Sea, and Eunicella singularis in the Gulf of Lions. Both species exhibit strong patterns of genetic structure at a regional scale, although the dispersal capacity of each species does not seem limited (>100 m). The third chapter discerns among the potential processes shaping the realized connectivity of E. singularis in the Gulf of Lions by applying the model presented in Chapter 1, and comparing the modeled patterns of genetic structure to the results obtained from empirical genetic data in Chapter 2. Modeled and empirical results show similar patterns of genetic structure among populations of E. singularis in the region. Genetic and demographic differentiation among populations is demonstrated to result from the spatial structure of dispersal alone. The ability to evaluate the expected development of genetic structure among populations under different demographic and hydrological scenarios using the seascape model presented in Chapter 1 provides a useful tool with relevance for marine spatial planning and the persistence of marine populations
McGarvey, Brian Scott. "Coupling of Solid-State and Electromagnetic Equations for the Computationally Efficient Time-Domain Modeling and Design of Wireless Packaged Geometries with NonlinearActive Devices". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14551.
Testo completoFeister, Scott. "Efficient Acceleration of Electrons by an Intense Laser and its Reflection". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461225902.
Testo completoАртюхова, Надія Олександрівна, Надежда Александровна Артюхова e Nadiia Oleksandrivna Artiukhova. "Сушіння дисперсних матеріалів у багатоступеневих поличних апаратах з активним гідродинамічним режимом". Thesis, Вид-во СумДУ, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42372.
Testo completoДиссертация посвящена вопросам теоретических и экспериментальных исследований процесса сушки в рабочем пространстве многоступенчатых гравитационных полочных сушилок с вертикальным секционированием рабочего пространства. Предложена физическая модель движения взаимодействующих потоков, что позволяет определить периоды сушки дисперсного материала касательно особенностей проведения данного процесса в гравитационной полочной сушилке. Создана математическая модель, описывающая: 1) закономерности сушки одиночной частицы и частиц во взвешенном слое в режиме стеснённого движения с определением времени прогрева и обезвоживания дисперсного материала; 2) гидродинамику движения газового потока, одиночной частицы и частицы в режиме стеснённого движения с определением времени пребывания дисперсной фазы в рабочем пространстве сушилки; 3) температурно-влажностные характеристики взаимодействующих потоков и эффективность каждой ступени сушилки с учетом гидродинамики рабочего пространства аппарата, конструкции полок, свойств сушильного агента и способа организации его движения. Экспериментально установлено влияние конструкции полки и организации движения сушильного агента на гидродинамические характеристики работы гравитационной полочной сушилки и время пребывания дисперсного материала в объеме аппарата. Определены основные гидродинамические режимы работы гравитационной полочной сушилки в зависимости от нагрузки по потокам, а также время пребывания дисперсной фазы в каждом из режимов. Получена критериальная зависимость, позволяющая прогнозировать значение коэффициента массоотдачи при сушке в гравитационных полочных сушилках. Получены данные о температурно-влажностных характеристиках взаимодействующих потоков и эффективности ступеней сушилки в зависимости от конструкции полки и организации движения сушильного агента. Показано, что за счет изменения конструкции полки и организации движения сушильного агента возможно управление временем пребывания обезвоживаемого материала и значением эффективности каждой ступени сушилки. На основе созданных физической и математической моделей и проведенных экспериментальных исследований разработана методика инженерного расчета многоступенчатых сушилок полочного типа с определением основных геометрических характеристик аппарата и температурно-влажностных параметров потоков дисперсного материала и сушильного агента. Предложена методика оценки энергоэффективности процесса сушки дисперсных материалов по критерию удельных энергозатрат на интенсификацию. Предложены и защищены патентами Украины новые высокоэффективные устройства для осуществления процесса сушки. Проведено опытно-промышленное внедрение полочных сушилок со сравнительным анализом товарной продукции, результаты которого показали высокую эффективность разработанного оборудования.
Thesis is devoted to theoretical and experimental researches of the drying process in the workspace of multistage shelf gravitational dryers with vertical sectioning of the workspace. In thesis it is proposed the analytical equations describing: regularities of a single particles drying and their aggregates; hydrodynamics movement of the gas flow, single particles and disperse material in the compressed flow regime; efficiency of stage drying of disperse material on each cascade shelf and totally in the device. The regimes of dryers were determined experimentally, it was studied the influence of shelf design and the organization of the drying agent movement on hydrodynamic indicators of flows movement in the working space of gravitational shelf dryer and intensity of disperse material dehydration, it is received the criteria dependence that allows to predict the value of the mass-transfer coefficient while drying in the gravitational shelf dryers. The methodology of engineering calculation of multistage shelf-type dryers with the determination of the basic geometric characteristics of the device and temperaturemoisture parameters of dispersed material and drying agent flows was developed based on the established physical and mathematical models and conducted experimental researches. It is proposed the methodology of energy efficiency evaluation of the drying of dispersed materials due the criterion of the specific energy consumption for intensification. New high-effective devices for the drying process are proposed and patented in Ukraine. Experimental and industrial adoption of shelf dryers was made alongside with the comparative analysis of commodity output, the results of which demonstrated the high efficiency of the devices.
Joubert, Rita. "Solid-liquid mass transfer in trickle bed reactors". Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-06242009-140938/.
Testo completoHassard, Patrick. "Dual-scale modelling of two-dimensional flow in porous media". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/211518/1/Patrick_Hassard_Thesis.pdf.
Testo completoMonteil, Hélène. "Development and implementation of the Bio-electro-Fenton process : application to the removal of pharmaceuticals from water A review on efficiency and cost effectiveness of electro- and bio-electro-Fenton processes: application to the treatment of pharmaceutical pollutants in water. Efficient removal of diuretic hydrochlorothiazide from water by electro-Fenton process using BDD anode: a kinetic and degradation pathway study Electro-Fenton treatment of the widely used analgesic tramadol using BDD anode: a kinetic, energetic and degradation pathway study Efficiency of a new pilot scale continuous reactor for wastewater treatment by electrochemical advanced oxidation processes: influence of operating conditions and focus on hydrodynamics Electrochemical advanced oxidation processes combined with a biological treatment for wastewater treatment: a deep understanding on the influence of operating conditions and global efficiency". Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC2045.
Testo completoElectrochemical advanced oxidation processes (EAOPs) constitute an efficient technology to treat the pharmaceuticals as they allow the formation of strong oxidants such as hydroxyl radicals able to remove nearly any type of organic contaminants thanks to their very high oxidation power. Among them the electro-Fenton and anodic oxidation processes are environmentally friendly methods as they use no chemical reagent (anodic oxidation) or only oxygen of air and iron ions as a catalyst (electro-Fenton).In this thesis, four pharmaceuticals from different families and structures were selected based on their toxicity and their occurrence in environmental waters and their removal from water was performed by EAOPs. The objectives of this work were to determine the best operating conditions at lab scale (current and catalyst concentration), investigate the kinetic of degradation and mineralization and finally propose a mineralization pathway based on aromatic intermediates, carboxylic acids and ions released to the solution.As these treatments were successfully applied, a lab scale pilot reactor composed alternately of BDD anodes and carbon felt cathodes with a bottom aeration system and working in the continuous mode was built to scale-up these processes in order to pre-industrialize them. Different configurations of electrodes were tested. The flow rate and the current were found to be more influent on the mineralization rate and on the energy consumption, respectively. To deeper understand the role of the flow rate and the configurations a hydrodynamic study was performed. The hydrodynamic results were gathered with a kinetic model for the mineralization to obtain a model predicting the percentage of mineralization at different position inside the reactor during the steady state. Thus, this model can help to optimize the operating conditions and to size future reactors depending on the mineralization objective of the treatment (high mineralization rate, combined treatment, high flow, …).To reduce operating cost, the combination of an electrochemical process and a biological treatment was then investigated. In this frame, it was found that electrochemical treatment can (i) degrade the hydrochlorothiazide (ii) reduce significantly the concentration of its aromatic intermediates as they were shown to significantly inhibit the bacterial activity, (iii) promote the formation of biodegradable molecules such as carboxylic acids. The biodegradation of four carboxylic acids formed during the electro-Fenton treatment of the hydrochlorothiazide at lab scale was also studied. It was demonstrated that they were sequentially degraded with different lag phases and kinetics of degradation. Thus to mineralize them, a “plug flow” type reactor is recommended. The combination of treatment was then applied with an electrochemical treatment performed at low current with a BDD anode and a Platine anode. A mineralization degree of 38% and 50% were obtained by the biological treatment enabling to globally reach a mineralization rate of 66% and 85% with the BDD and the Platine anodes respectively. Thus this combined treatment was successful and open the way for the scale-up of these processes
TrongNhan, Le, e 黎仲仁. "HYDRODYNAMIC EFFICIENCY ENHANCEMENT OF DIFFUSER AUGMENTED TURBINE". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7x2nm6.
Testo completo國立成功大學
航空太空工程學系
105
Nowadays, renewable energy plays a crucial role in building a more sustainable life for the world by cutting back the energy consumption from traditional fossil fuel sources-the main cause of global warming. Beside the conventional kinds of renewable energy such as wind and solar, marine current energy has yet been significantly deployed although it has the greatest potential of energy. One of the recent technology for marine tidal current energy conversion is the utilization and adaptation of the conventional horizontal-axis turbine with the implementation of diffuser-augmented duct. This duct enables the turbine performance be raised a significant percentage. The main purpose of this research is to study the possibility and physics that can further enhance the hydrodynamic performance of the diffuser-augmented tidal turbine with a nozzle add-on device. Hydrodynamic performance assessment and model design is based on computational fluid dynamics (CFD) simulations. A comparison of the potential performance of the original ducted turbine and the modified models with nozzle add-on was also carried out. The add-on nozzle is designed to create a converged channel surrounding the duct outlet in order to accelerate the outbound flow and create a pressure drop surrounding the duct outlet. Hence, it creates a larger pressure difference between the inlet and outlet flow of the system. Wider pressure difference will result in a greater mass flow entering the system leading to the improvement in power output. Moreover, the pressure difference also is bigger across the blade surface and generates bigger torque and power output. Parametric study of the design in various configurations, mainly the nozzle length and the nozzle inlet/outlet area ratios, have been conducted to understand the influence of the geometric parameters on the turbine performance. The results confirmed that the overall hydrodynamic efficiency of the diffuser-augmented turbine has been significantly improved. The maximum hydrodynamic efficiency improvement was found to be equal to 28.2% with the nozzle add-on device implemented.
Lui, Song-He, e 劉松河. "An experimental study on removing efficiency of surface roughness for hydrodynamic polishing process". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/07407291324573541648.
Testo completo國立中山大學
機械工程學系研究所
88
Abstract The removing efficiency of surface roughness for the hydrodynamic polishing process under semi-contact lubricating condition was investigated in this thesis. The experimental relationships between surface roughness and polishing were first examined. From the relationships, the potential influential factors of the removing efficiency and the magnitude of surface roughness were identified. Finally, a mathematical model that was related to the removing efficiency and the magnitude of surface roughness was proposed. Based on the experimental study, it was shown that the surface roughness would be rapidly reduced at the beginning by polishing process and then hardly improved afterward. This trend implied that surface roughness would not be completely removed during the polishing process. It was proposed that the amplitude and wavelength of surface roughness would affect the removing efficiency of surface roughness. Further, the removing efficiency was not sensitive to the tool velocity. From the mathematical model, several points were concluded. First, the removing efficiency was positively proportional to the amplitude of surface roughness. Second, the removing efficiency was inversely to the amplitude of surface roughness. Third, the removing efficiency was inverse proportional to a waviness of tool surface. Fourth, the removing efficiency was not sensitive to tool velocity. Finally, there existed an achievable minimum surface roughness for a surface with specific wavelength. The magnitude of a minimum surface roughness was shown to be proportional to the wavelength of work surface.
Peng, Chen-Chieh, e 彭振捷. "Application of 2D Hydrodynamic Model to Assess the Dredging Efficiency of Malun Stream". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/35422877946758298905.
Testo completo國立中興大學
水土保持學系所
104
This research aims to evaluate the efficiency of dredging scenarios in Malun stream by using CCHE-2D hydrodynamic model. The dredging scenarios were: do-nothing, dredge at the main stream with compound cross-section, and dredge at the confluence of the Malun stream and Lanyang river. Considering different depths of dredge at the confluence, there were six dredging scenarios investigated in the present study. Through the simulation of the bed changes in a flood event, the aggradation of the dredging areas were used to evaluate the efficiency of dredging scenarios. The verification of CCHE-2D model showed the Modified Engelund & Hansen formula with the adaptation length equal to 1000 meters successfully rep resented the bed changes in the study areas. The simulation results showed the averaged height of aggradation was about 1.5 meters near the Malun bridge in the do-nothing scenario. The corresponding value of dredge at the main stream increased to 1.7 meters, because the sediment was trapped in the dredging areas. Near the Malun bridge, it resulted in a decrease of the areas of the crosssection and a corresponding decrease of ability to pass flood. However, dredge at the confluence showed an increase of flow velocity and ability of sediment transport. Moreover, the height of aggradation decreased with the increase of dredging depth. As the dredging depth ranging at 1.5~2.0 meters, the height of aggradation was less than 1.0 meters. Dredge at the confluence of the Malun stream and Lanyang river was found to the most effective dredging scenarios among the others.
Chen, Chien-Cheng, e 陳乾成. "Efficiency Assessment of Soil Washing Plant Using Hydrodynamic Separation and Chemical Extraction Technology". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/qa3xz9.
Testo completo國立屏東科技大學
環境工程與科學系所
106
While industries developed in Taiwan, some factories did not adequate dispose sewage that made some fields contaminated seriously by heavy metal. Heavy metals in soil can be absorbed differently by different particle size. Soil washing that separate the particles by hydrodynamic or sieve, and/or chemical extract heavy metals on soil particles, is one of the feasible technology for heavy metal contaminated soils. However, it still has some limitations. In this study, six contaminated soil samples were collected for soil washing to find out the limitations of this technology. Six sites ( N, C, T, L, D and J ) of soil samples were collected from factories and agricultural fields. Cu is the contaminant of soil T and Cr are others’. Soils N, C, T and L came from a soil treatment plant. We collected samples from each washing unit and evaluate the extraction efficiency of the process. We also do laboratory scale test, using sequential sedimentary technology to separate soils into four particle sizes (sand, coarse silt, fine silt, clay), to compare the result. Soil liquid ratio 1:2 or 1:10 of 0.1 N HCl chemical extractions were applied on silt and clay. For high Cr soil L and soil D, 0.1 N HCl and EDTA consecutive extraction were applied for better extraction efficiency. In this study, 20% of Cu in soil T was the three easy extracted fractions (water-soluble fraction, exchangeable fraction and carbonate fraction). Cr in soils N, C, L, D and J were distributed in the most stable three fractions (Fe-Mn Oxide fraction, organic fraction and residual fraction) which had less environmental impact. Soil particles separated in laboratory showed that the concentration of heavy metals varied with the soil particles size. Most sands were uncontaminated except those from high Cr soil L and soil D. Simulates real plant chemical extraction using 0.1 N HCl showed that extraction efficiency of six soils were less than 30%. Soil T has the highest extraction efficiency (28%). Raising the soil liquid ratio can improve the heavy metals extraction efficiency. The consecutive extraction of 0.1 N HCl and EDTA has better extraction efficiency than 0.1 N HCl. 0.1 N HCl can extract part of Cr of Fe-Mn oxide fraction and consecutive extraction can extract almost all the Cr of Fe-Mn oxide fraction. After soils N, C and T were treated by chemical extraction in real plant, both coarse particles and fine particles were clean. However, the recovery rates of heavy metal were still unbalanced. According to the results, soil washing technology is not proved to be suitable for high contaminated and low sand content soil.
Shen, Shen-Yu, e 沈昱伸. "Investigating the Trapping Efficiency of Detention and Deposit ponds by using a Hydrodynamic Model". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34237731748671224667.
Testo completo國立中興大學
水土保持學系所
104
According to the Soil and Water Conservation technology norms of the Soil and Water Conservation Bureau of the Council of Agriculture of Executive Yuan, people should dredging at least one time each year when setting up the trapping efficiency of detention and deposit ponds inside the development base on the slope land, in order to maintain enough volume of detention and deposit ponds. Moreover, people should consider the convenience of dredging when designing, and maintaining adequate air ventilationlest for producing biogas which may cause danger This research uses the real example as the object of research, using the flow model CCHE2D to investigate the iji3mpacts of the sedimentation area of different positions of outlet and inlet of detention and deposit ponds, and different detentions and deposit ponds aspect ratio. By the velocity of flow inside the detention and deposit ponds and the position of the sand drops and deposits, and the quantity of the sand drop as basis to judge the benefits of the detention and deposit ponds to achieve the goal of designing the controlling Settlement location to improve the efficiency of detention and deposit ponds. According to the research, there would be the deposit of the mud in the place where there is a vortex, the speed of the circulation and on the corner inside the pound. Furthermore, when the distance of the inlet is far away from the outlet , it meets the Soil and Water Conservation technology standard better.by contrast, if the distance is closer, it can cause the jet stream and can’t defer the flood to meet the time effect Keyword: detention and deposit ponds, silting basin efficiency, CCHE2D
Tsai, Hung-Yuan, e 蔡鴻源. "Use of hydrodynamic methods to enhance membrane filtration efficiency of sugar produced by rice straw hydrolysis". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/07168944999290714056.
Testo completo淡江大學
化學工程與材料工程學系碩士班
100
The separations of sugars from hydrolysis suspension using hollow fiber and flat plate membranes are studied. The effects of operating conditions and hydrodynamic methods on the sugar separation performance are discussed. The hollow fibers used in the experiments are made of polysulfone, and their mean pore size is 10 kD. In the filtration of pure glucose, the main resistance source is the membrane because of trivial membrane fouling, and the sugar transmission decreases slightly under high pressures. When enzyme exists in the suspension, the filtration rate decreases about 85 - 90% compared to those in the filtration of pure glucose. The major resistances are due to the enzyme blocking in the membrane pores and the cake formation on the membrane surface. Increasing the transmembrane pressure results in higher glucose yield. However, this effect becomes trivial when the pressure exceeds 80 kPa. An increase in cross-flow velocity under fixed transmembrane pressure leads to higher filtration rate. The filtration rate increases three times when cross-flow velocity increases from 0.3 to 1.5 m/s. Some empirical equations are established to correlate the filtration resistances with operating conditions. The filtration rate can be estimated accurately by substituting the calculated resistances into modified Darcys’ law. In addition, several hydrodynamic methods are tested to increase the filtration rate. A pulse feeding way may increase the filtration rate by 24.7%, while the way of step-increasing pressure can increase the filtration rate as high as 34.6%.
Wales, Nadine Jenifer. "The effect of prewetting on the residence time distribution and hydrodynamic parameters in trickle bed reactors". Diss., 2008. http://hdl.handle.net/2263/27723.
Testo completo- Non-wetted
- Levec-wetted
- Super-wetted
Dissertation (MEng)--University of Pretoria, 2008.
Chemical Engineering
unrestricted
Elhanafi, ASSM. "Performance and survivability of offshore oscillating water column wave energy converters". Thesis, 2017. https://eprints.utas.edu.au/23971/2/Elhanafi_whole_thesis_ex_pub_mat.pdf.
Testo completoPusha, Ayana T. "Multiple turbine wind power transfer system loss and efficiency analysis". 2013. http://hdl.handle.net/1805/3800.
Testo completoA gearless hydraulic wind energy transfer system utilizes the hydraulic power transmission principles to integrate the energy of multiple wind turbines in a central power generation location. The gearless wind power transfer technology may replace the current energy harvesting system to reduce the cost of operation and increase the reliability of wind power generation. It also allows for the integration of multiple wind turbines to one central generation unit, unlike the traditional wind power generation with dedicated generator and gearbox. A Hydraulic Transmission (HT) can transmit high power and can operate over a wide range of torque-to-speed ratios, allowing efficient transmission of intermittent wind power. The torque to speed ratios illustrates the relationship between the torque and speed of a motor (or pump) from the moment of start to when full-load torque is reached at the manufacturer recommended rated speed. In this thesis, a gearless hydraulic wind energy harvesting and transfer system is mathematically modeled and verified by experimental results. The mathematical model is therefore required to consider the system dynamics and be used in control system development. Mathematical modeling also provided a method to determine the losses of the system as well as overall efficiency. The energy is harvested by a low speed-high torque wind turbine connected to a high fixed-displacement hydraulic pump, which is connected to hydraulic motors. Through mathematical modeling of the system, an enhanced understanding of the HTS through analysis was gained that lead to a highly efficient hydraulic energy transmission system. It was determined which factors significantly influenced the system operation and its efficiency more. It was also established how the overall system operated in a multiple wind turbine configuration. The quality of transferred power from the wind turbine to the generator is important to maintaining the systems power balance, frequency droop control in grid-connected applications, and to ensure that the maximum output power is obtained. A hydraulic transmission system can transfer large amounts of power and has more flexibility than a mechanical and electrical system. However high-pressure hydraulic systems have shown low efficiency in wind power transfer when interfaced with a single turbine to a ground-level generator. HT’s generally have acceptable efficiency at full load and drop efficiency as the loading changes, typically having a peak around 60%. The efficiency of a HT is dependent on several parameters including volumetric flow rate, rotational speed and torque at the pump shaft, and the pressure difference across the inlet and outlet of the hydraulic pump and motor. It has been demonstrated that using a central generation unit for a group of wind turbines and transferring the power of each turbine through hydraulic system increases the efficiency of the overall system versus one turbine to one central generation unit. The efficiency enhancement depends on the rotational speed of the hydraulic pumps. Therefore, it is proven that the multiple-turbine hydraulic power transfer system reaches higher efficiencies at lower rotational speeds. This suggests that the gearbox can be eliminated from the wind powertrains if multiple turbines are connected to the central generation unit. Computer simulations and experimental results are provided to quantify the efficiency enhancements obtained by adding the second wind turbine hydraulic pump to the system.
(7026707), Siddharth Saksena. "Integrated Flood Modeling for Improved Understanding of River-Floodplain Hydrodynamics: Moving beyond Traditional Flood Mapping". Thesis, 2019.
Cerca il testo completoΣεργίδης, Ανδρέας. "Μελέτη των παραμέτρων της σύνθεσης υβριδικών κολλοειδών νανοκρυστάλλων με υπερπαραμαγνητικές ιδιότητες για την ανάπτυξη πολυλειτουργικών συστημάτων ελεγχόμενης χορήγησης αντικαρκινικών ουσιών". Thesis, 2014. http://hdl.handle.net/10889/8576.
Testo completoPaclitaxel (PTX) is one of the most successful anticancer drugs against a broad range of solid tumors, such as metastatic breast cancer, ovarian cancer, non-small-cell lung cancer and AIDS-related Kaposi sarcoma. However, the serious systematic side effects of PTX (myelosuppression, neurotoxicity, hypersensitivity) underline the need for formulation of PTX in Drug Delivery Systems (DDS), in order to reduce the side effects and increase the bioavailability of the drug. Among DDS, polymeric micelles have drawn much attention due to their great flexibility in tuning drug solubility, micelle size, targeted drug delivery and stability. Incorporation of Superparamagnetic Iron Oxide Nanocrystals (SPIONs) inside the core of drug-loaded polymeric micelles, imparts to the final Drug Delivery System the prospect of physical (magnetic) targeting, intrinsic therapeutic function (hyperthermia-based cancer therapy under alternating external magnetic field), T2-based contrast enhancement in magnetic resonance imaging (MRI) and remotely triggered drug release. These core-shell polymeric micelles having small size (100-200nm), are considered appropriate for avoiding both opsonization, macrophages attack by ReticuloEndothelial System (RES) and rapid renal clearance, thus allowing micelles to be taken up preferably by solid tumors through Enhanced Permeability and Retention (EPR) effect. Therefore, such nanoassemblies encode high potential in nanomedicine, due to their dual nature (Therapeutic+Diagnostic = Theranostics). In particular, we have studied the synthesis of organophilic SPIONs through thermal decomposition. The synthetic parameters (precursor, precursor:oleic acid ratio, reaction temperature and duration, heat rate, etc.) affecting the size, shape and size distribution of the nanocrystals have also been examined thoroughly, since they play a key-role concerning the magnetic behavior of the final hybrid. Nanosized SPIONs with narrow size distribution were synthesized (5-13nm, σ: 10-20%). The preparation of poly(lactic acid)-block-poly(ethyleneglycol) (PLA-PEG) micelles encapsulating hydrophobic SPIONs, by varying the molecular weight of the polymers, the amount of SPIONs and the addition rate during micelle assembly, has also been investigated. The core-shell superparamagnetic micelles were prepared through solvent diffusion and evaporation technique (nanoprecipitation). PTX and SPIONs are being incorporated into the micelle’s hydrophobic core (PLA) through hydrophobic interactions, whereas the hydrophilic shell (PEG) stabilizes the micelles in aqueous dispersions, optimizing their colloidal stability and providing prolonged circulating time. The optimum parameters were determined, conferring to the micelles (Hydrodynamic Diameter < 200nm) high colloidal stability (up to six months) at biorelevant conditions (pH:7.4, ionic strenght: 0.15M). The next phase of the present master thesis focused on studying the factors (amount of PTX and SPIONs, molecular weight of PLA-PEG, addition rate, etc.) affecting the Loading of PTX and SPIONs into the polymeric micelles and how they can be fine-tuned towards high drug loading, while retaining their size at a scale where long circulation would not be precluded. Through protocol establishment, we have managed to separate the magnetic and non magnetic micelles, and to determine individually the loading of PTX and SPIONs for magnetic, non magnetic micelles, as well as for the mixture of them. The micelles’ mixture exhibits very high Drug Encapsulation Efficiency (93 %wt.) and 4.8 %wt. Drug Loading (D.L). Magnetic nanocarriers display high Magnetic Encapsulation Efficiency (70 %wt.), with D.L and Magnetic Loading of 5.2 and 20 %wt. respectively, In both cases, micelles demonstrate adequate magnetic behavior and small sizes (hydrodynamic diameter: 170nm), under conditions which simulate with human plasma (pH:7.4, ionic strenght: 0.15M). The effect of SPIONs’ size on the magnetic behavior of hybrid colloids, was also examined. Magnetic nanocarriers encapsulating SPIONs of greater size exhibit better magnetic behavior. Finally, we have conducted Drug release studies in PBS (0.14M, pH:7.4) at 37oC. The effect of SPIONs presence on the release profile of PTX, including triggered drug-release by application of AC magnetic field, has also been investigated. PTX-magnetic micelles exhibit Controlled Drug release for 24 hours. Several techniques have been used for the characterization of such nanoassemblies, like: HPLC, DLS, TGA, TEM, XRD, Magnetophoresis and Triggered Drug release by application of AC magnetic field.