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No / Optimal design and operation of MSF desalination process is considered here using MINLP technique within gPROMS model builder 2.3.4. gPROMS provides an easy and flexible platform to build a process flowsheet graphically and the corresponding master model connecting automatically individual unit model equations during simulation and optimisation. For different freshwater demand throughout the year and with seasonal variation of seawater temperature, the total annualised cost of desalination is minimised. It is found that seasonal variation in seawater temperature results in significant variation in design and some of the operating parameters but with minimum variation in of process temperatures. The results also reveal the possibility of designing stand-alone flash stages which would offer flexible scheduling in terms of the connection of various units (to build up the process) and efficient maintenance of the units throughout the year as the weather condition changes. In addition, operation at low temperatures throughout the year will reduce design and operating costs in terms of low temperature materials of construction and reduced amount of anti-scaling and anti-corrosion agents.

An extension of the original Ott-Grebogy-Yorke control scheme is used on a simple double pendulum. The base point of the double pendulum moves in both horizontal and vertical directions which leads to rather complicated behavior.A delay coordinate is used to reconstruct the attractor. The required dimension is determined by the False Nearest Neighbor analysis. A newly developed Fixed Point Transformation method is used to identify the unstable periodic orbit (UPO). Two different system parameters are used to control the motion. Minimum parameter constraints are studied. The use of discrete values for parameter changes is also investigated. Based on these investigations, a new on-off control scheme is proposed to simplify the implementation of the controller and minimize the delay in applying the control. / Ph. D.

Developing a single fixed-time artificial insemination (FTAI) protocol would benefit small-scale and niche market pork producers by decreasing semen costs and labor associated with detection of estrus. The objective of this study was to test the efficacy of an artificial insemination (AI) breeding system using triptorelin acetate, a GnRH agonist (OvuGel®; JBS United Animal Health, LLC, Sheridan, IN) that induces ovulation. A total of 96 sows (parity, 3.5 ± 0.2; body condition score (BCS), 2.5 ± 0.07) were weaned (h 0) after a 24.8 ± 0.6 d lactation on five participating small swine farms and allocated to one of four treatment groups: 1) TRT1: (n = 24) OvuGel applied intravaginally at h 96 and AI at h 120; 2) TRT2: (n = 24) P.G. 600® (400 IU eCG and 200 IU hCG, Merck Animal Health, Inc., De Sota, KS) injected intramuscularly at weaning, OvuGel at h 96 and AI at h 120; 3) TRT3: (n = 24) P.G. 600 at weaning, and AI at 0 and 24 h after first detection of estrus; and 4) TRT4: (n = 24) AI at 0 and 24 h after first detection of estrus. Treatments 1 and 2 were FTAI protocols with sows being inseminated without regard to estrus onset. Treatments 3 and 4 were consistent with current industry AI practices. The proportion of females displaying estrus by d 7 post-weaning was greater (P < 0.05) for sows that received OvuGel (94.5 %) compared to sows that did not receive OvuGel (82.2 %). There were no effects (P > 0.05) of P.G. 600 or P.G. 600 x OvuGel on females displaying estrus by d 7 or d 10 post-weaning. Weaning to estrus interval was decreased (P < 0.05) for sows that received P.G. 600 (4.9 ± 0.4 d) compared to sows that did not receive P.G. 600 (5.4 ± 0.4 d). There were no effects (P > 0.05) of OvuGel or P.G. 600 x OvuGel on the weaning-to-estrus interval. There were no effects of P.G. 600, OvuGel or P.G. 600 x OvuGel (P > 0.1) on pregnancy rate (total sows pregnant/inseminated) (61.2 %), total litter size (11.3), number born dead (1.0) or number of mummies (0.2). There was an effect (P < 0.05) of P.G. 600 x OvuGel on total born live (10.2). Sows treated with OvuGel had a greater number of live piglets born per semen dose (5.4) compared to sows that did not receive OvuGel (3.2) (P < 0.05). These results suggest that FTAI protocols may be employed on small-scale pig farms without compromising reproductive performance. / Master of Science

Yes / Multi-Stage Flash (MSF) desalination process has been used for decades for making fresh water from seawater and is the largest sector in desalination industries. In this work, dynamic optimisation of MSF desalination is carried out using powerful and robust dynamic simulation and optimisation software called gPROMS model builder. For a fixed freshwater demand, a number of optimal combinations of the factors such as heat transfer area, brine flow rate, cooling water flow rate, steam flow in brine heater, Top Brine Temperature, the number of stages, etc. are determined with the objective of maximising the performance ratio of the process (defined as the amount of fresh water produced per unit of energy input) considering the seasonal variations. An attempt has been made to develop an operational schedule for a particular day using dynamic optimisation.

The performance of Biostyr media using an upflow biofilter scheme was investigated. Three separate Modes that varied the organic strength of the influent at an operating temperature of 12°C were evaluated to explore how nitrification and denitrification responded to different concentrations of biodegradable COD loadings. Effluent suspended solids and observed yield coefficients were also analyzed along with ways to determine kinetic parameters. Combinations of primary and secondary effluent were used as the influent using domestic wastewater from a primary sewer of the Blacksburg VPI Sanitation Authority, in Blacksburg, Virginia, located on the Virginia Tech Campus. Reduction of nitrification rates was observed in the aerobic reactor at biodegradable COD loadings to the aerobic biofilter of 2.2 kg/day/m³ and greater. Complete denitrification was observed in the anoxic tank at biodegradable COD loadings to the anoxic biofilter of 7.5 kg/day/m³ and greater. Above this value, denitrification was limited by the available amount of NOx-N. An optimum influent biodegradable COD loading rate of 7.5 kg/day/m³ to the anoxic biofilter and 2.2 kg/day/m³ to the aerobic biofilter was experimentally demonstrated for simultaneous nitrification and denitrification. When secondary effluent was fed to the reactors, complete nitrification was observed indicating success in terms of ammonia polishing. However, low concentrations of influent biodegradable COD limited the ability for the anoxic reactor to denitrify. Thus, it was determined that the addition of an external carbon source would need to be implemented to denitrify when using low strength secondary effluent. Effluent total suspended solids were consistently below 20 mg/L indicating that secondary clarification would not be needed for this reactor scheme. The combined observed yield was consistently around 0.2 (mg-VSS/mg-COD consumed) or less. However, the evaluation of separate anoxic and aerobic yields was inconsistent when averaging data over 5 days, because of the recycle of biomass from the aerobic reactor back to the anoxic reactor. The kinetic parameters, q'_{MAX NIT} and K’_{S NIT} were calculated by plotting nitrification rates as a function of ammonia concentration. These coefficients were calculated by using separate segments within the media under less than optimal conditions. It was determined that analyzing the whole system rather than segments would be better suited for kinetic parameter analysis. However, there was not enough collected data to achieve this. Thus, ranges identifying further influent biodegradable COD loadings were recommended for later research to better a complete kinetic parameter evaluation. / Master of Science

The performance of Integrated Fixed Film Activated Sludge (IFAS) was evaluated for its effect on nitrification and denitrification in a bench scale biological nutrient removal (BNR) process configured as a Virginia Initiative Project (VIP) process. The IFAS systems consisted of a sponge - like biomass support system (Captor) operated in the aerobic zone of two independent treatment trains, and a fibrous biomass support system (Ringlace) operated in the aerobic zone of one independent treatment train. A fourth treatment train containing no biomass support system was operated as a control. A range of four aerobic MCRTs was studied, from 3.4 days to 1.7 days. All experiments performed for this research effort were conducted using domestic wastewater obtained directly from Blacksburg, VA and the Virginia Tech campus. Results indicated that the presence of the sponge - like biomass support media (Captor) freely floating in the aerobic zone mixed liquor greatly increased the ability of that system to achieve nitrification at temperatures of 12 degrees Celsius and aerobic suspended growth MCRTs as low as 1.7 days. A statistical t-test analysis demonstrated this with 99% confidence. Results early in the research, as well as previous research by Mitta (1994) indicated that fibrous biomass support systems (Ringlace) did not perform as well with respect to nitrification as did Captor, and experiments on Ringlace were discontinued midway through the research. Increased denitrification throughout the IF AS/Captor train was noted as a result of the increased nitrification. However, the use of Ringlace appeared to enhance denitrification which occurred in the aerobic zone. Further study is recommended to verify this data. A decrease in sludge production in the IFAS train containing Captor could not be statistically established. However, observed sludge yield coefficients for the IF AS/Captor train were consistently lower than those for the Control train. A statistical analysis was not performed, but the values varied considerably so that direct comparison was difficult. / Master of Science

The research described in this dissertation deals with an open problem concerning the synthesis of controllers of xed order and structure. This problem is encountered in a variety of applications. Simply put, the problem may be put as the determination of the set, S of controller parameter vectors, K = (k1; k2; : : : ; kl), that render Hurwitz a family (indexed by F) of complex polynomials of the form fP0(s; ) + Pl i=1 Pi(s; )ki; 2 Fg, where the polynomials Pj(s; ); j = 0; : : : ; l are given data. They are specied by the plant to be controlled, the structure of the controller desired and the performance that the controllers are expected to achieve. Simple examples indicate that the set S can be non-convex and even be disconnected. While the determination of the non-emptiness of S is decidable and amenable to methods such as the quantier elimination scheme, such methods have not been computationally tractable and more importantly, do not provide a reasonable approximation for the set of controllers. Practical applications require the construction of a set of controllers that will enable a control engineer to check the satisfaction of performance criteria that may not be mathematically well characterized. The transient performance criteria often fall into this category. From the practical viewpoint of the construction of approximations for S, this dissertation is dierent from earlier work in the literature on this problem. A novel feature of the proposed algorithm is the exploitation of the interlacing property of Hurwitz polynomials to provide arbitrarily tight outer and inner approximation to S. The approximation is given in terms of the union of polyhedral sets which are constructed systematically using the Hermite-Biehler theorem and the generalizations of the Descartes' rule of signs.