Flavor lexicons are used in sensory evaluation to determine the flavor profile of a food product. The objective of this study was to develop a flavor lexicon for cooked beef, which can then be used in various projects relating to beef quality such as studies investigating animal diet, marinating, ageing, or other enhancements. A descriptive panel of 10 people was used to develop a flavor lexicon of 18 attributes, including astringent, barny, bloody, brothy, browned, gamey, grassy, juicy, fatty, livery, metallic, oxidized, roast beef, and the five basic tastes (bitter, salty, sour, sweet, and umami). In contrast to other studies on beef, this lexicon was developed to include both positive and negative attributes. The lexicon was able to show that rib eye steaks from the Longissimus dorsi muscle in grass-fed animals were significantly (p<0.05) higher in barny, bitter, gamey, and grassy flavors, and lower in juicy and umami flavors. The steaks were also rated by consumers, who showed a preference for grain-fed beef over grass-fed beef. The ratings of the descriptive panel were related to the consumer panel scores to equate the lexicon terms with a positive or negative consumer degree of liking score. Those terms that were considered positive in this study due to their positive correlation with consumer liking include brothy, umami, roast beef, juicy, browned, fatty, and salty. The terms that were inversely associated with consumer liking were barny, bitter, gamey and grassy, among others. A separate descriptive panel was conducted on the Spinalis dorsi (or “cap” muscle) of the rib eye steak, with similar results. Additionally, descriptive and consumer evaluations found no difference between two types of grass diets, namely alfalfa and sainfoin. Different mixtures of beef and chicken were also evaluated to determine flavor differences between the two meats. Chicken was found to be more closely correlated to brothy, juicy, sweet, and umami, among others, while beef was found to be more closely correlated to terms such as gamey, bloody, oxidized, metallic, roast beef, and astringent. Throughout these tests, the newly developed lexicon was shown to be an effective tool for profiling fresh meat samples.

There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the SCD gene. We propose that if cattle were raised to a constant body weight, their MUFA:SFA ratio will be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus cattle were acquired for this study. Cattle were slaughtered at weaning at 8 mo of age (SFCF, n=4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (MFCF, n=4) and 16 mo of age (LFCF, n=4). Twelve cattle were assigned to the YF group and slaughtered at 12 mo of age (SFYF, n=4) 16 mo of age (MFYF, n=4) and market weight of 525 kg (LFYF, n=4). Cattle were then statistically analyzed based on time on high energy diet. Fatty acids from digesta, plasma, liver, L. dorsi, and s.c. and i.m. adipose tissue were all analyzed by FAME. In s.c. 18:1 and 16:1 were greatest in LFCF (41.27% and 5.58%, respectively, P = 0.05), and 18:0 and 16:0 did not differ between groups (P > 0.10). MUFA:SFA ratios of s.c. tended to be higher in LFCF animals (1.26) vs. LFYF (1.06, P = 0.10). However, there was no difference seen when comparing CF to YF animals (P = 0.26). MUFA:SFA ratio was higher in i.m. (P = 0.03) and also increased with age (P < .01). A trained sensory panel saw no significant differences between palatability of flavor characteristics of cooked steaks from LFCF, MFYF, or LFYF (P > 0.05). We showed increased SCD gene expression in the LFYF (248.41 to 1528.69 SCD/GAPDH, P = 0.01). Expression was higher in YF (P = 0.04), but their initial deposits of SFA, combined with the lack of SCD expression while on pastures, prevented the MUFA:SFA ratio from increasing at a rate fast enough to change the final ratios in the animal.

There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the SCD gene. We propose that if cattle were raised to a constant body weight, their MUFA:SFA ratio will be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus cattle were acquired for this study. Cattle were slaughtered at weaning at 8 mo of age (SFCF, n=4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (MFCF, n=4) and 16 mo of age (LFCF, n=4). Twelve cattle were assigned to the YF group and slaughtered at 12 mo of age (SFYF, n=4) 16 mo of age (MFYF, n=4) and market weight of 525 kg (LFYF, n=4). Cattle were then statistically analyzed based on time on high energy diet. Fatty acids from digesta, plasma, liver, L. dorsi, and s.c. and i.m. adipose tissue were all analyzed by FAME. In s.c. 18:1 and 16:1 were greatest in LFCF (41.27% and 5.58%, respectively, P = 0.05), and 18:0 and 16:0 did not differ between groups (P > 0.10). MUFA:SFA ratios of s.c. tended to be higher in LFCF animals (1.26) vs. LFYF (1.06, P = 0.10). However, there was no difference seen when comparing CF to YF animals (P = 0.26). MUFA:SFA ratio was higher in i.m. (P = 0.03) and also increased with age (P < .01). A trained sensory panel saw no significant differences between palatability of flavor characteristics of cooked steaks from LFCF, MFYF, or LFYF (P > 0.05). We showed increased SCD gene expression in the LFYF (248.41 to 1528.69 SCD/GAPDH, P = 0.01). Expression was higher in YF (P = 0.04), but their initial deposits of SFA, combined with the lack of SCD expression while on pastures, prevented the MUFA:SFA ratio from increasing at a rate fast enough to change the final ratios in the animal.

Master of Science / Department of Agricultural Economics / Ted C. Schroeder / With the decline in negotiated trade in the live cattle cash market, feedyards and packers are looking for new ways to increase cash trade. An online, fed cattle auction was created to increase transparency as well as increase the cash trade. Hedonic models have been used heavily to study feeder cattle and the value placed on their characteristics. There is little hedonic modeling done on live cattle and the value of their characteristics. The Fed Cattle Exchange is a new online platform, therefore, no research has been done on it. The objective of this research is to use hedonic modeling to determine the value packers place on characteristics of each lot of fed cattle sold. These characteristics include, weight, number of head, sex, days on feed, location, yield grade, quality grade, delivery time period, and use of a beta-agonist. This research found that use of a beta agonist, location, days on feed, number of head, weight, delivery time frame as well as inclusion of a Select percentage were all statistically important to the price paid. Results will benefit feedyards by informing the sellers on what buyers find the most desirable. This will help with both feedyard procurement practices as well as feedyard management practices.

>Magister Scientiae - MSc / The ecology of spring fed rivers has been under-studied in South Africa. As a result, little is known or documented on the effects of seasonal variation of flows on the species diversity, distribution and abundance of aquatic macroinvertebrates in rivers dominated by spring discharges in, South Africa. In order to expand our understanding of the structure and functioning of spring fed rivers, the study determined and compared the current ecological state of the spring fed Liesbeek River tributary and the non-spring fed Disa River focusing on discharge, water quality and macroinvertebrates.

A nutritional method commonly used to deliver feedings to premature infants is the use of a gavage tube. To measure for any undigested breastmilk or formula, a gastric aspirate is checked prior to the next feeding. There is a gap in practice as to what to do if these aspirates signify feeding intolerance. The project question centered on identifying evidence-based guidelines in the literature that would help to define best practices related to feeding intolerance of gavage-fed infants. The Johns Hopkins Nursing Evidence-Based Practice model and the Appraisal of Guidelines Research and Evaluation provided the frameworks for gathering and evaluating evidence as well as the process used in forming the practice guideline. The primary methods employed were a team approach that included a Neonatal Intensive Care Unit (NICU) Project Team and NICU expert opinion along with a literature review conducted by the doctor of nursing practice student. The NICU Project Team collected the NICU experts' input via surveys they developed and distributed as well as e-mails to authors identified from the literature review. The surveys yielded a 76% response rate from the registered nurses and a 59% response rate from the medical providers. All data collected were shared and descriptive statistics were used to evaluate the data. One of the central research findings was that gastric aspirates should no longer be routinely obtained on stable infants and, if used in evaluating feeding intolerance, they must be used in combination with other indicators. An enteral feeding guideline was developed to reflect this finding that can be shared with other NICUs and nurseries in the United States and globally to decrease the morbidity and mortality of neonates.

Among the renewable energies, wind energy presents the highest growth in installed capacity and penetration in modern power systems. This is why reliability of wind turbines becomes an important topic in research and industry. To this end, condition monitoring (or health monitoring) systems are needed for wind turbines. The core of any condition monitoring system (CMS) are fault diagnosis algorithms whose task is to provide early warnings upon the occurrence of incipient (small magnitude) faults. Thanks to the use of CMS we can avoid premature breakdowns and reduce significatively maintenance costs. The present thesis deals with fault diagnosis in sensors of a doubly-fed induction generator (DFIG) for wind turbine (WT) applications. In particular we are interested in performing fault detection and isolation (FDI) of incipient faults affecting the measurements of the three-phase signals (currents and voltages) in a controlled DFIG. Although different authors have dealt with FDI for sensors in induction machines and in DFIGs, most of them rely on the machine model with constant parameters. However, the parameter uncertainties due to changes in the operating conditions will produce degradation in the performance of such FDI systems. In this work we propose a systematic methodology for the design of sensor FDI systems with the following characteristics: i) capable of detecting and isolating incipient additive (bias, drifts) and multiplicative (changes in the sensor gain) faults, ii) robust against changes in the references/disturbances affecting the controlled DFIG as well as modelling/parametric uncertainties, iii) residual generation system based on a multi-observer strategy to enhance the isolation process, iv) decision system based on statistical-change detection algorithms to treat the entire residual and perform fault detection and isolation at once. Three novel sensor FDI approaches are proposed. The first is a signal-based approach, that uses the model of the balanced three-phase signals (currents or voltages) for residual generation purposes. The second is a model-based approach that accounts for variation in the parameters. Finally, a third approach that combines the benefits of both the signal- and the model-based approaches is proposed. The designed sensor FDI systems have been validated using measured voltages, as well as simulated data from a controlled DFIG and a speed-controlled induction motor. In addition, in this work we propose a discrete-time multiple input multiple output (MIMO) regulator for each power converter, namely for the rotor side converter (RSC) and for the grid side converter (GSC). In particular, for RSC control, we propose a modified feedback linearization technique to obtain a linear time invariant (LTI) model dynamics for the compensated DFIG. The novelty of this approach is that the compensation does not depend on highly uncertain parameters such as the rotor resistance. For GSC control, a LTI model dynamics is derived using the ideas behind feedback linearization. The obtained LTI model dynamics are used to design Linear Quadratic Gaussian (LQG) regulators. A single design is needed for all the possible operating conditions.

QC 20100618

ABSTRACT Wind energy is among the fastest growing renewable energy technologies in the world that has been increasing by about 30% a year globally. Wind energy has proven to be a clean, abundant and completely renewable source of energy. Owing to the rapidly increasing use of wind power, the aspect of integrating high level of penetrations wind power into the grid is becoming more and more of reality. Examples of large wind farms in the United States are the 781.5 MW Roscoe wind farm in Texas, the 735.5 MW Horse Hollow Wind Energy Center in Taylor and Nolan County, Texas, the 845 MW Shepherds Flat wind farm in Oregon and the 1550 MW Alta wind farm being developed in California. As most large wind farms in North America employ Doubly-fed Induction Generator (DFIG) wind turbines, their voltage-sourced converter-based back-to-backs offer independent control of the real and reactive power. The use of these control capabilities have been recently proposed for damping power swings, inter-area oscillations as well as subsynchronous resonance. There is, however, a question that is always associated with the use of voltage-sourced converter -based back-to-back wind farms for damping power system oscillations: what happens when there is no wind? The keyword to the answer is “combined”. The potential benefit of using these types of wind farms for damping power system oscillations should always be combined with conventional damping devices (power system stabilizers, thyristor controlled series capacitor, static synchronous series compensator, high voltage dc systems, etc.). This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the potential use of supplemental controls of DFIG-based wind farms combined with a phase imbalanced hybrid series capacitive compensation scheme for damping power system oscillations. The thesis also addresses the recent concern over the case of large share of wind power generation which results in reducing the total inertia of the synchronous generators and degrading the system transient stability. In this regards, the results of the investigations have shown that in such a case; properly designed supplemental controllers for the wind farm converters could be an asset in improving the system transient stability rather than degrading it. Time-domain simulations are conducted on a benchmark model using the ElectroMagnetic Transients program (EMTP-RV).

In response to the global climate change and environmental protection needs, more and more nations take renewable energies as one of the major future energy policies for its characteristics of clean, low greenhouse gas emission and self-productivity. Among Taiwan¡¦s many renewable energy development, wind energy is always on the list. Wind energy will not only avoid the problems of carbon dioxide which cause greenhouse effect, but also refrain pollution caused by fossil fuel or nuclear energy. The induction generator is a fundamental component of a wind machine. It¡¦s electric port and control can be classified into single fed control and double fed control. Through various comparisons of control and operation, double fed control seems to be more stable at present. Double fed induction generator may continuously produce power at island state without the supply of reactive power from parallel capacitor or the synchronous generator. which is the biggest advantage than single fed induction. , In other words, double fed induction generator may supply power independently. The induction generator is a time-varying and non-linear component. So the traditional rule of scalar control is not adopted in the thesis. The induction generator can be linearized by using vector control, and the power flow can also be directed with the control of its composition of rotor current vector and the controller is designed under the above methodology. The thesis aims to simulate, analyze and compare the steady and transient states of single fed and double fed wind generators with the purposes a more through understanding of the controller and its operation.