For an offshore platform structure applied to wave-energy conversion system, in order to catch the maximum waves to generate more powers, similar to wind-energy power generators, a range of angles for the devices normal to the propagating direction of incident waves is required, particularly when the power converting system has directional preference. In this study, an electro-magnetic wave energy conversion device was developed and tested in a single-mooring offshore platform system. In order to find the best design parameters for the electro-magnetic generators system in various wave periods a water-tank experiment was designed and performed. During the experimental study, both wave parameters and dimensional related parameter of the generator were under investigation. It was found in this study that the newly developed wave conversion system can work well under certain periods and height of waves. The relationships between the parameter were presented into figures.

As a solitary wave is usually used to characterize the behavior of a tsunami, a hydraulic experiment is set up for a detailed study of the associated celerity and particle trajectory. The size of the water tank of this experiment in this paper is 21m long, 0.5m width and 0.7m deep. Wave maker method used by Goring (1978) for simulating Solitary Waves is applied in the experiment of particle trajectories and mass transport. We also extend the particle trajectories theory to higher order that contains the non-linear terms. The method presented in this paper fixes the position of the camera, and the grid-point board is located in the center of the water tank, so that the particle and the two-dimensional grid surface coincide. Then, we analyze the particle trajectories within the grid with image processing techniques. This method not only save time of coordinate calibration, but also get a more accurate measurement. The water particle used in this paper has 1mm diameter, because it is difficult to locate the exact position of a large particle. Because of the small size in this experiment, we can get better results and the error is reduced. To compare with the experiment, the third-order Eulerian solution of Feton(1972) is transferred to the Lagrangian system in the present study to get the particle velocity. Then an integral with respect to time is used to obtain the trajectory. The accuracy of the theory is good, especially in the regime of small amplitude. For large wave amplitude in terms of the water depth, a higher order solution is suggested for the future study.

The present study developed a new ¡V typed Photobioreactor, ¡§ Automatically Temperature Controllable and Wave-Mixed Photobioreactor System, ATCWPS ¡§ . The main propose of the study is to reduce the energy consumption and production cost during the process of cultivation. It can be cut down the over-dependent of nature resource on the land and expand the ocean by using the advantage of the nature marine environment. The Photobioreactor based on baffled tanks is investigated and the effect of the displacement of the Photobioreactor induced by external waves on liquid sloshing is discussed. The vortices generated by baffles can mix the fluid in the Photobioreactor. The influence of water depths and baffle height can be utilized to develop the model of Photobioreactor by simulating the inner change of energy, and to decrease the temperature of Photobioreactor with the characteristic of seawater specific heat. The problem of non-averaged light in the system by optical fiber system of total internal refraction is also improved in this work. The result of the experiment made in the Shi-Hzuwan ( Bay ) aquaculture site shows the average temperature of algae liquid can be declined about 20%. The results of vibrating platform cultivation shows the baffled system can increase the energy of mixing micro-algae in the growing process. Optical fiber system of total internal refraction can enhance the light efficiency, and thus not only can improve the shading effect among algae, but speed up its growing rate. When the staggered baffles and the optical fiber system of total internal refraction are combined, the optimal result of the growth rate of algae can be obtained in this work.

Wave is one of the most common dynamic factors in marine engineering. This is the major affecting factor in the design of structures and coastal engineering that wave affect the structure or the coast, so there are many topics about wave absorbing issues. In this paper, FLOW-3D modeling is implemented for wave interaction with porous structures, and comparing with experiment. This is very different between the results of models using the proposed method by the FLOW-3D User Manual to set drag coefficients of porous media and the results of experiments. Therefore, to discuss the setting drag coefficients of porous media is one of this research project. Configuration of this study, four different types of porous structures to explore the interaction with wave, the major categories: single, double and three-tier (two forms). FLOW-3D simulations of wave boundary in this article is to simulate the wave plate to manufacture wave, FLOW-3D simulations of wave with the previous studies are different with its built-in wave boundary. The results of simulation compare with experiment, and obtain water depth data both of them, and then programmatically wave analysis explore the differences between simulation and experiment. The simulation results show that stroke set by the analog wave board need to reduce 10 percent of the original settings, and the simulation results are similar to experiment results. The differences between simulation and experiment are smaller when porous media parameter ¡¥b¡¦ setting formula adjust to 0.03/D ( D is the particle diameter)and parameter ¡¥a¡¦ setting formula changeless. Reducing wave of the four porous structures relate to the wave period. The wave period is bigger and more difficult to wave absorption, and the reflectivity is proportional to wave period.

In this study, a laboratory-scale activated sludge reactor and a biotrickling filter were constructed to study the removal of methyl tert-butyl ether (MTBE) from air vented from contaminated sites. The activated sludge tank (0.4 m¡Ñ0.4 m cross-sectional area, 3.0 m height, and 480 L total volume) was made by acrylic resin. A mixed liquor suspended solids (MLSS) concentration of 2000-3000 mg/L was maintained in the experimental mixed liquor and the sludge was acclimated for 30 days under selected conditions of a Food to Microorganism Ratio (F/M) of 0.3 g BOD/(g MLSS¡Dday) and an influent gas MTBE concentration (C0) of 180 mg/Am3 (@27oC). Results on performance tests show that an average MTBE removal efficiency of 93.6% was obtained with the operation conditions of C0 of 610 mg/Am3 (@27oC), volumetric aeration rate of 0.063 m3/m3¡Dmin, MLSS of 2600 mg/L, and submerged liquid depth of 1.0 m. The biotrickling filter was made by combining two same type of acrylic resin columns (each 0.2 m inner diameter, 2.0 m height, and packed with 900 pieces of polypropylene Pall rings to a height of 1.35 m) in series for the test gas flow and in-parallel for the trickling liquid flow. Each test was operated for 8 hours to reach a steady state for a set of selected conditions (gas flow rate 0.050 m3/min and superficial gas velocity 0.027 m/s, trickling liquid flow rate 0.004 m3/min and pH: 6.8-7.2, and liquid/gas flow ratio: 80 L/m3). Results show that the MTBE removal efficiencies from the influent gas were 40%, 22% and 15%, respectively, with C0 of 50,100 and 230 mg/Am3 (@27oC).

It has been confirmed that vented gases from swine manure compositing operations contain biodegradable ammonia and amines as main odorous compounds. The thesis focuses on the odor-removal performance from the gases by sparging them into an activated sludge aeration liquor in which the odorous compounds can be absorbed and biodegraded. An acrylic column (0.20 m i.d.¡Ñ1.2 mH) was used as the activated sludge aeration tank and a wooden case (1.0 mL¡Ñ0.6 mW¡Ñ0.6 mH) as a swine manure compositing tank. Seed sludge for the odor removal experiments was obtained from a swinery wastewater plant located at southern Taiwan. Both swine manure from the swinery and a pre-fermented composite sample obtained from a compositing plant located at East-southern Ping-Dong County were used for the odorous gas generation. Experiments were conducted at mixed liquor suspended solid (MLSS) concentrations of 2,250-2,750 mg/L, liquid pH of 6.4-6.6, and aeration intensities of 0.1-0.5 m3/m3.min. Results show that the experimental removal efficiencies for both ammonia and amines with, respectively, 18-50 and 180-250 ppm in the influent gas were greater than 80% with aerated activated sludge liquid depths of greater than 0.60 m within the tested aeration intensities. Keeping the activated sludge at around 25oC favored the biodegradation of the absorbed ammonia and amines and resulted in the removal of the compounds to around 85-95%. Temperatures of lower than 15oC shifted the removal to as low as 50-60% because of the limitations in both the biological growth and activity. Results from the study confirm that the activated sludge bioscrubbing approach should be applicable to odor control for the compositing plants.

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Στην παρούσα διπλωματική εργασία, στόχος είναι η παρατήρηση και ο σχεδιασμός παρατηρητή πλήρους αλλά και μειωμένης κατάστασης τόσο γενικά όσο και ειδικά με εφαρμογή στο σύστημα των τριών διασυνδεδεμένων δεξαμενών(Amira DTS2000).Πιο συγκεκριμένα, θα γίνει χωρισμός της διπλωματικής εργασίας σε τέσσερα(4) κεφάλαια. Το πρώτο, στο οποίο θα γίνει η παρουσίαση του μοντέλου των τριών(3) δεξαμενών (Amira DTS2000) και η σύνδεσή του με την διαδικασία της παρατήρησης και του σχεδιασμού παρατηρητή. Στο δεύτερο κεφάλαιο θα παρουσιαστούν μέθοδοι παρατήρησης που αφορούν σε μη γραμμικά συστήματα, όπως το υπό μελέτη σύστημα. Στο τρίτο κεφάλαιο με βάση όσα έχουν μελετηθεί από το δεύτερο κεφάλαιο θα γίνει σχεδίαση παρατηρητή πλήρους αλλά και μειωμένης κατάστασης και τέλος στο τέταρτο κεφάλαιο θα γίνει προσομοίωση του συστήματος σε Μatlab και για τα δυο είδη παρατηρητών και από την σύγκριση θα βγουν συμπεράσματα για το πως ο κάθε παρατηρητής επηρεάζει την απόκριση του συστήματος μας. / --

Underwater autonomous vehicles are frequently used for deep-water ocean applications such as surveying and cable-laying, where accurate control of vehicle depth and attitude is needed. The water level in the on-board ballast tanks are typically manually set for neutral buoyancy before each mission, while the vehicle is on the surface. The resulting weight of the water level is not normally adjusted while the unmanned vehicle is in operation to control vehicle depth and orientation. As a result, vehicle trajectory and orientation is exclusively controlled using the vehicle’s control surfaces during a mission. The challenges with controlling the depth and trim of an underwater vehicle include nonlinear hydrodynamic forces as well as relatively slow response times and inherent time delays (latencies) associated with water tank level changes and valve adjustments. To meet these challenges, this thesis proposes two unique variable ballast system control approaches. The proposed control approaches may be suitable for large autonomous underwater vehicles with both small (volume = 0.027 m3, each) and large (volume = 0.216 m3, each) ballast tanks. The first proposed variable ballast system controller uses the current parameters of the ballast tanks to determine the appropriate action to be implemented. This controller was designed change the weight of the AUV to help control vehicle parameters such as depth and vertical (inertial) velocity. The second proposed variable ballast controller attempts to shift the center of gravity x_G along the body-fixed x-(longitudinal) axis by changing the weight in the ballast tanks. By shifting the center of gravity, the controller attempts to reduce depth and pitch angle error while regaining control authority to the bowplane and sternplane deflection fins. The ballasting system consists of two water tanks positioned aft and forward of amidships. The ballast tanks are then automatically filled or emptied of ocean water as desired. Setpoint depth control and x_G shifting numerical simulations have been carried out on a two-dimensional underwater vehicle simulator to test and compare the performance of the proposed ballast and deflection control systems. The simulation results show that, for the assumptions and conditions tested, the proposed controllers are versatile and capable of achieving a setpoint depth and pitch angle with minimal error by effectively utilizing the ballast tanks and deflection fins. As a result, the work presented in this thesis helps increase the autonomy of large AUVs on long duration missions.

A novel multi-tank thermal energy storage (TES) was evaluated experimentally and numerically. The multi-tank storage is based on the interconnection of standard hot water storage tanks by a single charge flow loop. Each tank is charged through a thermosyphon loop and natural convection heat exchanger (NCHE). Both series- and parallel-connected configurations were investigated and results show that high degrees of stratification can occur. To predict the performance of the series- and parallel-connected multi-tank TES, a numerical model was developed and implemented in the TRNSYS simulation environment. Laboratory tests were also conducted to measure the unit’s performance under charge conditions representative of combinations of clear and overcast days. The effects of rising and falling charge loop temperatures and power levels on storage temperatures and heat transfer rates were studied and indicated that sequential stratification was achieved in the series-connected storage. Under certain conditions, reverse flow through the thermosyphon loops was identified, leading to destratification and carry-over of heat to the downstream storage tanks. Consequently, a new model was developed and showed to model reverse thermosyphon operation. A subsequent analysis showed that these effects could be minimized by careful system design. To quantify the relative benefits of the sequentially stratified TES, values of exergy stored versus time were determined and compared against fully stratified and fully mixed storages. Results show that the series configuration closely matches the exergy level attained by a perfectly stratified storage. Finally, annual simulations conducted for a typical multi-family installation showed that the multi-tank storage performed at a level comparable to a single, fully stratified, storage. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2009-06-24 00:13:01.142