Some research suggests that development of professional learning communities might be the organizational strategy that could make school reform more successful. While most schools have not institutionalized the essential components of learning organizations, studies have demonstrated that these attributes must be developed if professional staffs are to realize the full benefit of organizational learning and in the process, create a context of improvement. The primary intent of this study was to learn and understand how principal behaviors influenced the development of shared leadership, shared vision, and supportive conditions; three essential dimensions of professional learning communities. Secondly, this study investigated how these conditions differed among schools which have and have not sustained high levels of student learning. Understanding the influence of principal leadership on conditions for organizational learning can be partially understood through either quantitative or qualitative methods. From this perspective, the mixed methods design utilized in this study allowed both qualitative and quantitative data to be analyzed and interpreted as evidence in understanding the study's problem. Principal and teacher focus-group interviews were used to create a deeper understanding of how principals worked to create conditions for organizational learning. Kouzes and Posner's (2002) Leadership Practices Inventory - Self and Observer Forms were utilized to identify, describe, and measure the perceived leadership practices of principals. The findings of this investigation suggest that principal leadership is a key factor in creating conditions for organizational learning and sustaining high levels of student achievement. Principals in this study who effectively identified and modeled espoused values were perceived to be highly visionary and appeared more effective at sharing leadership, inspiring vision, and creating supportive conditions. Principals who were able to develop a shared vision among staff created strong collaborative cultures characterized by an uncompromised focus on student learning. The findings of this study also indicated that principals who effectively Model the Way, Inspire a Shared Vision, and Enable Others to Act, distributed leadership among staff and demonstrated a systems orientation to leading.

Repair and remodeling of bone during healing and fusion require a combination of bone resorption and formation to successfully restore the bone to its previous strength. The healing process is highly responsive to the mechanical conditions of the construct, where excessive loading can cause high strains that delay healing, but moderate loading can be beneficial. Maintaining compression at the site of fracture can benefit healing by maintaining bone congruency and increasing the stability of the bone-implant construct to prevent excessive shifting. For these reasons, compressive mechanisms are employed in many orthopaedic devices, including both intramedullary (IM) nails and external fixators for ankle arthrodesis applications. Tibiotalocalcaneal (TTC) arthrodesis is a salvage procedure that fuses both the ankle and the subtalar joints. It has become the standard of care in ankle degeneration, which can be brought on by posttraumatic arthritis, failed total ankle arthroplasty, or diabetic conditions such as Charcot arthropathy. While current devices are effective in many cases, TTC arthrodesis procedures still incur failure rates as high as 22%, where failure of the bones to successfully fuse can result in amputation. Because bone healing relies upon bone resorption, the initial compression applied to the implanted constructs can be quickly lost, which may sacrifice the stability of the structure and delay or inhibit further healing. By employing a mechanism that can sustain compression during the bone healing process, it was possible to increase the stability of the construct even during bone resorption, minimizing the failures that still occur. The focus of this study was to determine the effects of compression on the mechanical stability of the implant-bone construct found in TTC arthrodesis. A comparison was made between the torsional stability of two currently marketed intramedullary devices, as well as a prototype IM device comprised of a nickel titanium core, designed to hold constant compression for up to 9mm of resorption. Additionally, the stability of each construct over time was evaluated by correlating bone resorption to a loss in compressive force.

The purpose of this study is to evaluate the association between sustained-release morphine (Avinza®), and performance on neuropsychological tests assessing short term memory, information processing, and motor skills in chronic pain patients, while controlling for stages of pain model variables and the effects of benzodiazepines. A convenience sampling procedure was utilized to enroll a sample of patients who had a trial of short-acting narcotic analgesics for their chronic non-malignant pain. Enrolled patients were treated with long-acting morphine Avinza.® Patient interviews were conducted at enrollment and one-month follow-up. A total of 129 patients were enrolled in the study. Mean pain intensity ratings at the highest, lowest, and average levels in the previous week were lower at follow-up (10.90, 4.56. 7.64) than at baseline (12.71, 6.76, 10.01) respectively. Reduction in pain levels was associated with a corresponding reduction in levels of pain unpleasantness, pain suffering, and pain behaviors. The models evaluating the associations between the stages of pain model variables, morphine dose, benzodiazepine dose, and digit span test (chi square = 147.79, p = 0.76), digit symbol test (chi square = 128.06, p = 0.5), and paced auditory serial attention test fit the data well (chi square = 160.39, p = 0.85). There was a statistically significant inverse association between frequency of pain behaviors and digit span test scores at baseline (-0.49, p = 0.01). Although the association between pain behaviors and digit symbol test scores (- 17. 0 %, p = 0.09) and paced auditory serial addition test scores (-4.0%, p = .28) at baseline were not statistically significant, a large negative effect was found. At follow-up, the association between pain behaviors and digit span test was positive and not significant. The negative association between frequency of pain behaviors and digit symbol test scores (-4.4%, p = 0.67 ) and paced auditory serial addition test scores (-2.8%, p = 0.21) at follow-up were considerably weaker. There were no significant association between opioid dose and cognitive function test scores. Opioid therapy, particularly, sustained release morphine therapy (Avinza) does not contribute to cognitive impairment in chronic pain patients. / text

Children with Fetal Alcohol Spectrum Disorder (FASD) may suffer numerous cognitive impairments, including significant problems with executive functioning, language, attention, and memory [40]. It is estimated that two to five percent of children born in the U.S. are affected by FASD [34]. It has been shown that training improvements can be made in working memory and attention in children with ADHD [25]. Computerized training with game elements enhances not only motivation but training efficacy of these interventions [38]. This thesis examines the creation of two suites of serious games, Cognitive Carnival and Caribbean Quest, intended to improve working memory aspects of attention with the assistance of a trained psychology interventionist in a therapeutic setting. A game-based approach is chosen to provide motivation to children for sustained cognitive challenges presented by cognitive exercises built into the gameplay. Cognitive Carnival was shown by interventionists to have positive effects in neuropsychological studies of populations of children with epilepsy and FASD [33, 30]. / Graduate

The aim of this research was to develop and fully investigate a novel method of antibiotic drug delivery to the lung that will address problems with current therapeutic regimens for treatment of airway infections. To demonstrate the performance of prepared formulations, the design of suitable characterization methods were also aimed. A novel dissolution method for evaluating the in vitro dissolution behavior of inhalation formulations was developed. The membrane holder was designed to enclose previously air-classified formulations so that they could be uniformly tested in the dissolution apparatus. Dissolution procedures, the apparatus, the dose collection, the medium, and test conditions were developed and the dissolution behaviors of test compounds were evaluated by experimental and mathematical analysis. It was proved that the aerodynamic separation of formulation prior to dissolution assessment have a significant influence on the dissolution profiles. The optimized test method using the membrane holder was applied to evaluate in vitro dissolution profiles of the manufactured formulations of rifampicin (RF). The carrier/excipient-free RF dry powder formulation was investigated. The rifampicin dihydrate (RFDH) powders having MMAD of 2.2 um were prepared using a simple recrystallization process. The RFDH powders have a thin flaky structure, and this unique morphology provides improved aerosolization properties at maximal API loading. The manufactured RFDH formulation showed 80% drug release within 2 hours. To retard the release rate of RF, the prepared RFDH crystals were coated with hydrophobic polymer, PLA or PLGA, using spray-dryer equipped with multi-channel spray nozzles. The multi-channel spray nozzle used in this study has two separate nozzles for aqueous solution and one for gas fluid. The RFDH crystals and the coating solutions were sprayed through the two separate liquid nozzles at the same time. The coated RFDH formulations were prepared using multi-channel spray nozzles. The coated formulations contained at least 50% w/w of RF with no change of their flaky morphology. The initial RF release was lowered by coating; the lowest initial RF release was observed from the coated powders with PLA polymer as 32% among the coated formulations. Overall, the 80% of RF was released within 8 hours. The RFDH and coated RFDH formulations delivered via the pulmonary route would be anticipated to provide higher local (lung) drug concentrations than that of orally delivered powders. Particularly, the coated RFDH powders deposited in the alveolar region may prolong the drug residence time in the site of infections. Additionally, it was proved that the RFDH and coated RFDH formulations provided much better stability than the amorphous RF. / text

Four specimens were tested to evaluate the shear performance of beams with carbon fiber reinforced polymer (CFRP) laminates and CFRP anchors under fatigue and sustained loading applications. The specimens consisted of 24-in. deep T-beams that were constructed and tested at Phil M. Ferguson Structural Engineering Laboratory at the University of Texas at Austin. The specimens were strengthened in shear with CFRP laminates anchored with CFRP anchors. One end of each specimen was strengthened using bonded CFRP laminates while the other end was strengthened using unbonded CFRP laminates. Two specimens were used for fatigue testing and two were used for sustained load testing. For each set of tests, one specimen was strengthened using CFRP laminates prior to cracking and one specimen was strengthened using CFRP laminates following the initial cracking of the specimen. The CFRP laminates showed no signs of deteriorations in strength during fatigue testing, with only small increases in strain occurring in the CFRP laminates during testing. After fatigue loading was completed, the specimens were monotonically loaded to failure. The failure loads were 5 to 15% lower than beams that were not subjected to fatigue loading. Sustained load tests were subjected to a constant midpoint load based on service load requirements for a period of 217 days. CFRP laminates performed well during sustained loading. CFRP strains increased slightly throughout testing, but no signs of deterioration were observed. For both types of tests, specimens strengthened using bonded CFRP laminates demonstrated an increased stiffness resulting in smaller crack widths and lower strains in the internal steel. These benefits were not as great in specimens strengthened after the initial cracking of the specimen. / text

An investigation was conducted to determine and compare the effect of cell current pulsing and "self-oxidation" in increasing the CO tolerance of a PEM fuel cell. The most effective pulsing parameter values were also determined. Current pulsing involves periodically demanding positive current pulses from the fuel cell to create an anode over-potential, while "self-oxidation" or sustained potential oscillations is achieved when the anode catalyst becomes so saturated with CO that the anode over-potential increases to a value at which CO is oxidized from the catalyst surface. The CO tolerance of a fuel cell system with a Pt-Ru anode was tested using 50 and 496 ppm CO in the anode fuel. The performance of the system declined with an increase in CO concentration. Current pulses of various amplitude, frequency, and duty cycle were applied to the cell while CO was present in the anode fuel. With 50 ppm CO in the anode fuel, the most effective pulse in increasing CO tolerance while maintaining normal cell operation was 1.0 A/cm2, 0.25 Hz, and a 5% duty cycle. A pulse (120 Hz, 50% duty cycle) similar to the ripple current often generated when converting DC to single-phase 60 Hz AC had a positive effect on the CO tolerance of the system, but at frequencies that high, the pulse duration was not long enough to completely oxidize the CO from the catalyst surface. With 496 ppm CO in the anode fuel, a pulse of 1.0 A/cm2, 0.5 Hz, and a 20% duty cycle proved most effective. When the cell was exposed to 496 ppm CO, without employing pulsing, "self-oxidation" occurred and CO was periodically oxidized from the catalyst surface. However, pulsing allowed the cell to operate at the desired voltage and power a higher percentage of the time than "self-oxidation"; hence, pulsing was more effective.

This thesis describes an experimental study on the long-term creep behaviour of adhesive anchors under sustained tensile loads in combination with different environmental exposures. A comprehensive background and literature review is presented, focusing on various bond stress models for adhesive anchors, factors affecting their bond behavior, and an overview of available testing standards and evaluation criteria. The experimental program comprises of 82 test specimens. The specimens consist of a cylindrical shaped concrete block of 300 mm (12 inch) in diameter and 200mm (8 inch) in depth, with 15M (No. 5) deformed steel bar post-installed to an embedment depth of six times the bar diameter or 125mm (5 inch). Three types of adhesives were used for anchor installation: Type-A a fast setting two component methyl methacrylate adhesive, Type-B a fast setting two part epoxy adhesive, and Type-C a standard set two part epoxy adhesive. The study is divided into four phases. Phase I consists of 27 static pullout tests to determine the yield strength (fy) and the maximum tensile capacity of each anchor system under three exposure conditions. Phase II and Phase III consist of 36 specimens tested under sustained load levels of 40%fy (32kN) and 60%fy (48kN)under normal laboratory conditions (room temperature) and moisture exposure, respectively. Phase IV consists of 9 specimens tested under sustained load with a load level of 40%fy (32kN) with exposure to freeze/thaw cycling. All sustained load tests lasted for a period of at least 90 days. The results of the static pullout testing showed that specimens with epoxy based adhesive exhibited stronger bond strength, forcing the anchor to fail by rupture prior to bond failure. Under sustained load testing, specimens with standard set epoxy based adhesive showed insignificant creep displacement under room conditions, however, when exposed to moisture noticeable creep displacements were recorded. Specimens with both fast setting epoxy and methyl methacrylate based adhesives showed higher creep displacements under environmental exposure (moisture, freeze/thaw) versus those kept at room temperature. Displacement data from creep testing were analysed and projected over a service life span of 50 years for room temperature exposure, and for 10 years for moisture and freeze/thaw exposures. Based on the analysis results, the service life of different anchor systems was estimated. An integrated qualification and testing protocol is proposed for the creep behavior of adhesive anchors under various environmental exposures.

No description available.

Thermo-acoustic instabilities in combustion chambers are generated by the interactions between a flame and the combustor acoustics, leading to a resonant coupling. These self-sustained oscillations may be observed in many practical systems such as domestic boilers, industrial furnaces, gas turbines or rocket engines. Although this phenomenon has already been the topic of many investigations, there is yet no generalized robust framework to predict the onset of these self-sustained oscillations and to determine the evolution of the flow variables within the combustor during unstable operation. This work builds on previous models and experiments to improve the description of the response of laminar conical flames to flow perturbations and the prediction of thermoacoustic instability in burners operating with conical flames. In the first part of the manuscript, an extensive review of conical flame dynamics modeling is undertaken and a general framework for the modeling of their Flame Transfer Function (FTF) is presented. The experimental setup and the diagnostics used to characterize their response to flow disturbances are then described. They are used to measure the FTF when the flames are submitted to harmonic flow perturbations. A novel experimental technique is also proposed to control the flow perturbation level at the burner outlet. It enables to modulate the flow with random white noise perturbations and to measure the FTF with a better frequency resolution. Results with this alternative technique compare well with results from the classical method using harmonic signals for small disturbances. Limits of this technique are also highlighted when the perturbation level increases. Different analytical expressions for the FTF of conical flames are derived in the second part of the thesis by progressively introducing more physics into the models. Models based on convected flow disturbances are extended by taking into account the incompressible nature of the perturbed velocity field. It is shown that the prediction of the FTF phase lag of a conical flame is greatly improved and collapses well with measurements. Then, a thorough investigation of the flame base dynamics interacting with the anchoring device is conducted by considering unsteady heat loss from the flame to the burner. This mechanism is shown to drive the motion of the flame base and the flame dynamics at high frequencies. It is also shown that this contribution to the FTF rules the high frequency behavior of the FTF as well as the nonlinear evolution of the FTF when the perturbation level increases. Finally, an analysis is conducted on the dynamics of a single conical flame placed into cylindrical flame tubes featuring different diameters. It is shown that confinement effects need to be taken into account when the burnt gases cannot fully expand. Large differences are observed between FTF measured for different confinement tube diameters. A new dimensionless number is derived to take these effects into account and make all the FTF collapse on a single curve. These different models are then used to model the response of a collection of small conical flames stabilized on a perforated plate. It is shown that by sorting out the different contributing mechanisms to the FTF, the expressions proposed in this work may be combined to capture the main behavior and correct phase lag evolution of these flames in the frequency range of interest for thermo-acoustic instability prediction.