A LYAPUNOV BASED APPROACH TO ENERGY MAXIMIZATION IN RENEWABLE ENERGY TECHNOLOGIES

This dissertation describes the design and implementation of Lyapunov-based control strategies for the maximization of the power captured by renewable energy harnessing technologies such as (i) a variable speed, variable pitch wind turbine, (ii) a variable speed wind turbine coupled to a doubly fed induction generator, and (iii) a solar power generating system charging a constant voltage battery. First, a torque control strategy is presented to maximize wind energy captured in variable speed, variable pitch wind turbines at low to medium wind speeds. The proposed strategy applies control torque to the wind turbine pitch and rotor subsystems to simultaneously control the blade pitch and tip speed ratio, via the rotor angular speed, to an optimum point at which the capture efficiency is maximum. The control method allows for aerodynamic rotor power maximization without exact knowledge of the wind turbine model. A series of numerical results show that the wind turbine can be controlled to achieve maximum energy capture. Next, a control strategy is proposed to maximize the wind energy captured in a variable speed wind turbine, with an internal induction generator, at low to medium wind speeds. The proposed strategy controls the tip speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximal for a particular blade pitch angle and wind speed by using the generator rotor voltage as a control input. This control method allows for aerodynamic rotor power maximization without exact wind turbine model knowledge. Representative numerical results demonstrate that the wind turbine can be controlled to achieve near maximum energy capture. Finally, a power system consisting of a photovoltaic (PV) array panel, dc-to-dc switching converter, charging a battery is considered wherein the environmental conditions are time-varying. A backstepping PWM controller is developed to maximize the power of the solar generating system. The controller tracks a desired array voltage, designed online using an incremental conductance extremum-seeking algorithm, by varying the duty cycle of the switching converter. The stability of the control algorithm is demonstrated by means of Lyapunov analysis. Representative numerical results demonstrate that the grid power system can be controlled to track the maximum power point of the photovoltaic array panel in varying atmospheric conditions. Additionally, the performance of the proposed strategy is compared to the typical maximum power point tracking (MPPT) method of perturb and observe (P&O), where the converter dynamics are ignored, and is shown to yield better results

HAPTICS IN ROBOTICS AND AUTOMOTIVE SYSTEMS

Haptics is the science of applying touch (tactile) sensation and control to interaction with computer applications. The devices used to interact with computer applications are known as haptic interfaces. These devices sense some form of human movement, be it finger, head, hand or body movement and receive feedback from computer applications in form of felt sensations to the limbs or other parts of the human body. Examples of haptic interfaces range from force feedback joysticks/controllers in video game consoles to tele-operative surgery. This thesis deals with haptic interfaces involving hand movements. The first experiment involves using the end effector of a robotic manipulator as an interactive device to aid patients with deficits in the upper extremities in passive resistance therapy using novel path planning. The second experiment involves the application of haptic technology to the human-vehicle interface in a steer-by-wire transportation system using adaptive control

African Clawed Toads Response to the Distance Choice of Lateral Line Stimuli

African Clawed Toads are a model organism for research on sensory integration due to their lateral line system that allows them to sense water movement. This study further investigates the choices made by toads when presented with two lateral line stimuli in the form of surface waves. When such stimuli are initiated simultaneously, toads tend to turn towards the more rostral stimulus or the nearer stimulus, waves from which arrive first. We introduced a delay between stimuli to allow the waves from the farther stimulus to arrive first. Toads were more likely to respond to a single stimulus than they were to a double stimulus (25% versus 18% of trials, respectively). In these responses to double stimuli, toads generally turn as accurately toward one stimulus or the other as they do toward single stimuli; this indicates a choice rather than a confused or mixed response. As before, both proximity and stimulus angle affect the choice; toads prefer the more rostral stimulus and the closer of the two stimuli. Finally, delaying one stimulus increased the toads\u27 choice of the first stimulus to arrive.https://engagedscholarship.csuohio.edu/u_poster_2017/1008/thumbnail.jp

THE INFLUENCE OF ENVIRONMENTAL VARIABLES ON THE HEIGHT GROWTH OF LOBLOLLY PINE (Pinus taeda) IN THE WESTERN GULF

Understanding the effects of environmental factors on stand growth is important in optimizing forest management plans. This study investigated the effects of soil and climate factors on the height growth (site index) of loblolly pine (Pinus Taeda L.) using data collected from permanent plots established in intensively-managed plantations across East Texas and Western Louisiana. The Chapman-Richards model was selected as the base model to describe the height-age relationships and important soil and climate variables were incorporated into the models as model parameter coefficient adjustors. Our results showed that the most important factors for predicting site index were nitrogen content of B horizon for soil and precipitation in spring and fall. Three models were developed, with one incorporating nitrogen of B horizon, one incorporating spring and fall precipitation, and the last one incorporating both the soil and climate variables. An increase in nitrogen content in B horizon and an increase in spring precipitation increased the tree height, but an increase in fall precipitation slowed tree height growth. The log-likelihood ratio tests showed that all three models had significantly smaller AIC than the base model. Compared to the base model, the three models also had larger model coefficient of determination (R2), smaller root mean squared error, and bias. All three models can be used to estimate site index of intensively-managed loblolly pine plantations in the region, but data used in this study were not large, and, therefore, caution should be taken in their application

African Clawed Toads Response to the Distance Choice of Lateral Line Stimuli

African Clawed Toads are a model organism for research on sensory integration due to their lateral line system that allows them to sense water movement. This study further investigates the choices made by toads when presented with two lateral line stimuli in the form of surface waves. When such stimuli are initiated simultaneously, toads tend to turn towards the more rostral stimulus or the nearer stimulus, waves from which arrive first. We introduced a delay between stimuli to allow the waves from the farther stimulus to arrive first. Toads were more likely to respond to a single stimulus than they were to a double stimulus (25% versus 18% of trials, respectively). In these responses to double stimuli, toads generally turn as accurately toward one stimulus or the other as they do toward single stimuli; this indicates a choice rather than a confused or mixed response. As before, both proximity and stimulus angle affect the choice; toads prefer the more rostral stimulus and the closer of the two stimuli. Finally, delaying one stimulus increased the toads\u27 choice of the first stimulus to arrive.https://engagedscholarship.csuohio.edu/u_poster_2017/1008/thumbnail.jp

Effect of heat and physiological stress on the growth performance, physiology and welfare of broiler chickens

PhD ThesisBroilers can be faced with a several stressful conditions during their production cycle which can have implications for both growth performance and animal welfare. Animal welfare encompasses the physical and mental well-being of animals, assessed from the biological functioning and subjective experience. The aims of this thesis were i) to develop and validate non-invasive means of assessing the welfare of broilers under physiological and episodic heat stress conditions, ii) to investigate the impact of episodic heat stress, physiological stress and light wavelength on the growth performance, physiology and welfare of broiler chickens and, finally, iii) to investigate a novel means of alleviating heat stress in broilers. Endogenous corticosterone measured in the urate sphere was suppressed by dexamethasone administration. In a cognitive bias task, birds offered mealworms injected with corticosterone to mimic chronic stress were pessimistic in their judgement about ambiguous positions. A positive correlation was established between physiological indicators of stress and cognitive bias. Although light wavelength was confounded with light intensity in our study, there was no difference in growth performance and cognitive ability of birds reared in the blue and red light, except for increased activity of birds in red light. Under simulated episodic heat stress, the change in CBT measured from a temperature-ID chip (ΔCBT-chip) and a data logger (ΔCBT-logger) was positively correlated. Significant positive correlations were found between the change in surface body temperature (SBT) under wing (ΔWT) and ΔCBT-chip, and between ΔWT and ΔCBT-logger. Significant positive regression equations relating change in CBT and RR with apparent equivalent temperature (a factor which combines environmental temperature and RH) were also developed. High temperature coupled with high RH aggravated the respiratory rate (RR) of broilers and this was accompanied by suppression of peening behaviour. High heat stress for 3 hours had a greater impact on birds than moderate heat stress for 6 hours. For broilers exposed to moderate heat stress, the provision of additional cup drinkers reduced the rise in CBT and the proportion of time spent in wing drooping behaviour, but enhanced SBTs suggesting increased heat dissipation.Federal University of Agriculture, Abeokuta, Ogun state, Nigeri

Editorial:The emergence of animal welfare science and policy in Africa, Asia and Latin America

Peer Reviewe

Quality of life with conservative care compared with assisted peritoneal dialysis and haemodialysis

Background. There is little information about quality of life (QoL) for patients with end-stage kidney disease (ESKD) choosing conservative kidney management (CKM). The Frail and Elderly Patients on Dialysis (FEPOD) study demonstrated that frailty was associated with poorer QoL outcomes with little difference between dialysis modalities [assisted peritoneal dialysis (aPD) or haemodialysis (HD)]. We therefore extended the FEPOD study to include CKM patients with estimated glomerular filtration rate ⌉10 mL/min/1.73m2 (i.e. individuals with ESKD otherwise likely to be managed with dialysis). Methods. CKM patients were propensity matched to HD and aPD patients by age, gender, ethnicity, diabetes status and index of deprivation. QoL outcomes measured were Short Form-12 (SF12), Hospital Anxiety and Depression Scale depression score, symptom score, Illness Intrusiveness Rating Scale (IIRS) and Renal Treatment Satisfaction Questionnaire. Frailty was assessed using the Clinical Frailty Scale. Generalized linear modelling was used to assess the impact of treatment modality on QoL outcomes, adjusting for baseline characteristics. Results. In total, 84 (28 CKM, 28 HD and 28 PD) patients were included. Median age for the cohort was 82 (79-88) years. Compared with CKM, aPD was associated with higher SF12 physical component score (PCS) [Exp B (95% confidence interval)=1.20 (1.00-1.45), P<0.05] and lower symptom score [Exp B=0.62 (0.43-0.90), P=0.01]; depression score was lower in HD compared with CKM [Exp B=0.70 (0.52-0.92), P=0.01]. Worsening frailty was associated with higher depression scores [Exp B=2.59 (1.45-4.62), P<0.01], IIRS [Exp B=1.20 (1.12-1.28), P<0.01] and lower SF12 PCS [Exp B=0.87 (0.83-0.93), P<0.01]. Conclusion. Treatment by dialysis, both with aPD and HD, improved some QoL measures. Overall, aPD was equal to or slightly better than the other modalities in this elderly population. However, as in the primary FEPOD study, frailty was associated with worse QoL measures irrespective of CKD modality. These findings highlight the need for an individualized approach to the management of ESKD in older people.Peer reviewedFinal Published versio

Polymorphisms, Haplotype Variability and Neutrality Test of Bronze Locus in Turkey (Meleagris gallopavo)

The bronze locus, identified as melanocortin-1 receptor (MC1R) gene, is involved in body coloration. We examined polymorphisms, haplotype variability and deviation from neutrality of bronze locus in Nigerian Indigenous Turkeys (NIT) using British United Turkeys (BUT) as control breed. Single-exon coding region of MC1R was sequenced. Polymorphisms were identified using MEGA v6 and CodonCode Aligner. In silico prediction of the functional effects of amino acid substitutions was done using SNAP2. Haplotypes were reconstructed using DnaSp v5. Eight polymorphisms were identified in MC1R gene of the birds with two novel polymorphisms: c.37C>A (neutral effect) and c.866T>G (gain-of-function) in NIT and BUT, respectively. Mutations c.450C>T and c.866T>G were unique to lavender NIT while c.186C>G was present in all birds. Two polymorphisms, c.866T>G and c.887C>T, were predicted to have functional effects. The highest genetic diversity was observed in lavender NIT while the least was observed in BUT. Fifteen (15) haplotypes were reconstructed, with MC1RBUT1 and MC1RBUT2 unique to BUT. Haplotype MC1R*4 was absent in all the birds used in this study while MC1R*5 was present in all NIT. Our study confirmed that MC1R*2 carried black (B) allele. Two novel haplotypes (MC1RNig1 and MC1RNig2) identified in this study also carried B allele. MC1RNig6, MC1RNig7 and MC1RNig8 were found to be unique to lavender. The novel polymorphisms and haplotypes identified in NIT and BUT could be used in differentiating them from other turkey breeds with the same plumage colours. Also, various polymorphisms and haplotypes identified in bronze locus of turkey are useful in breeding programmes aimed at developing or conserving different plumage colour types

Polymorphisms, Haplotype Variability and Neutrality Test of Bronze Locus in Turkey (Meleagris gallopavo)

The bronze locus, identified as melanocortin-1 receptor (MC1R) gene, is involved in body coloration. We examined polymorphisms, haplotype variability and deviation from neutrality of bronze locus in Nigerian Indigenous Turkeys (NIT) using British United Turkeys (BUT) as control breed. Single-exon coding region of MC1R was sequenced. Polymorphisms were identified using MEGA v6 and CodonCode Aligner. In silico prediction of the functional effects of amino acid substitutions was done using SNAP2. Haplotypes were reconstructed using DnaSp v5. Eight polymorphisms were identified in MC1R gene of the birds with two novel polymorphisms: c.37C>A (neutral effect) and c.866T>G (gain-of-function) in NIT and BUT, respectively. Mutations c.450C>T and c.866T>G were unique to lavender NIT while c.186C>G was present in all birds. Two polymorphisms, c.866T>G and c.887C>T, were predicted to have functional effects. The highest genetic diversity was observed in lavender NIT while the least was observed in BUT. Fifteen (15) haplotypes were reconstructed, with MC1RBUT1 and MC1RBUT2 unique to BUT. Haplotype MC1R*4 was absent in all the birds used in this study while MC1R*5 was present in all NIT. Our study confirmed that MC1R*2 carried black (B) allele. Two novel haplotypes (MC1RNig1 and MC1RNig2) identified in this study also carried B allele. MC1RNig6, MC1RNig7 and MC1RNig8 were found to be unique to lavender. The novel polymorphisms and haplotypes identified in NIT and BUT could be used in differentiating them from other turkey breeds with the same plumage colours. Also, various polymorphisms and haplotypes identified in bronze locus of turkey are useful in breeding programmes aimed at developing or conserving different plumage colour types