Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Two-stage system"”.
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The Mesophilic and Thermophilic Anaerobic Digestion of Instant Coffee Waste Waters
… coffee factory's physical waste treatment systems and their resulting waste streams were identified and samples of wastewater were analysed to determine the physical and chemical characteristics relevant to anaerobic digestion. Two wastewater types were chosen for treatment by anaerobic …
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A merged two-stage converter for LED lighting applications
… an LED string. This thesis investigates a merged two-stage LED driver for lighting applications, with a switched capacitor (SC) voltage preregulator and a HF resonant-transition inverted buck current regulator. The design, analysis and implementation of the HF stage are developed in detail, and a …
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A Fuzzy/Neural Approach to Cost Prediction with Small Data Sets
… using various combinations of fuzzy and neural systems. The data set available for this cost prediction problem consists of variables such as test duration, thrust, and many other similar quantities, unfortunately it is small and incomplete. The first method implemented to perform this cost …
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Energy valorization of agro-industrial wastes and sweet sorghum for the production of gaseous biofuels through anaerobic digestion
… of agro-industrial wastes were performed in a two-stage system consisting of two continuously stirred tank reactors (CSTRs) under mesophilic conditions (37°C). Subsequently, more mixtures were studied, where sweet sorghum was added, in order to simulate the operation of a centralized AD plant …
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International biogas applications
… of approximately 1.19 Mm3 /year (42 TJ/year). A two-stage continuous fermentative hydrogen and methane co-production using macro-algae (Laminaria digitata) and micro-algae (Arthrospira platensis) was tested in laboratory trials. The hydraulic retention time (HRT) of the H2 reactor was set at 4 …
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Multi-stage polymer systems for the autonomic regeneration of large damage volumes
… to increase material lifetimes and safety, these systems have been limited to recovery of internal microcracks and surface damage. Current technologies thereby fail to address the restoration of large, open damage volumes. A regenerative chemistry was developed by incorporating a gel scaffold …
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Two-stage reverse osmosis : optimal element configuration and flux distribution, energy savings
In a two-stage reverse osmosis (RO) system of finite size, there are two degrees of freedom not present in a single-stage RO system: distribution of RO elements between the two stages (system design), and feed pressures (system operation). In this study, we investigate the optimal system design and …
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Foam fractionation and air flotation treatment of a tarsand extraction wastewater
… were: 1) to ascertain the feasibility of using a two-stage foam separation system, with foam fractionation or air flotation as the second stage, to treat a tarsand extraction wastewater; and, 2) to evaluate the effects of four operational variables on the second stage performance. The wastewater …
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Cellulose mineralization in two-stage anaerobic digestion systems
… solid waste/sludge, particulate cellulose, by two-stage anaerobic digestion systems. Cellulose hydrolysis and methanogesis were examined in both the thermo-meso and acid-methane two-stage systems under different hydraulic retention times (HRTs), feed concentrations and organic loading rates …
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Improving the bioconversion of lignocellulosic feedstock to bio-fuels and chemicals
… rye grass) in different anaerobic digestion systems, evaluating the role of substrate specificity on the pattern of degradation. The two-stage (biohydrogen-biomethane) anaerobic system was found to be more effective in the degradation of lignocellulose, when compared to the conventional …
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Using Anaerobic Co-Digestion With Addition of Municipal Organic Wastes and Pre-Treatment to Enhance Biogas Production From Wastewater Treatment Plant Sludge
… co-digestions with FOG were investigated in a two-stage thermophilic semi-continuous flow co-digestion system modified to incorporate thermo-chemical pre-treatment of pH=10 at 55°C. Overall, the modified two-stage co-digestion system yielded a 25.14±2.14 L/d (with 70.2±1.4% CH4) biogas …
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Mercury species in natural gas condensate
… sample injection procedure. For a given column system the positive identification and quantification of up to eight mercury species was obtained. A maximum injector temperature of 125oC was recommended, to avoid the conversion of species. Mass balance calculations show a strong correlation …
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Hydrogen production via dark fermentation of carbohydrate-rich substrates
… end-products from the hydrogen-producing stage could be fed to a second anaerobic digestion stage to recover more energy as methane and to stabilise the effluent. Although anaerobic digestion is well established, fermentative hydrogen production is not.<br/><br/>This work evaluated the …
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Near-capacity MIMOs using iterative detection
… to attain additional performance gains, the DSTS system invokes iterative detection, where the outer code is constituted by a Recursive Systematic Convolutional (RSC) code, while the inner code is a SP demapper in one of the prototype systems investigated, while the other scheme employs a Unity …
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Fast transfer path analysis using controlled electric motors as in-situ blocked force vibration sources
… induced by the electric power steering (EPS) system. Regarding noise, vibration and harshness (NVH), engineers require practical tools to assess, design and troubleshoot steering noise in vehicles. For acoustic development and refinement, test-based methodologies such as Transfer Path Analysis …
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The dual digestion of sewage sludge using air and pure oxygen
Dual Digestion is a two-stage system that combines autothermal thermophilic aerobic pre-treatment with conventional anaerobic digestion. The practicability of the system using pure oxygen is well proven. Disadvantages are the high cost of the pure oxygen and the absence of a detailed evaluation of …
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The development of a mathematical model for the bioextraction of the critical raw material magnesium from mine waste using acidithiobacillus caldus
… model. Both batch and continuous flow reactor systems were investigated for their suitability and performance in magnesium recovery. The system was optimised using a pH control system and a two-stage flowsheet design. Chemical leaching kinetics were determined by fitting the models to …