Thesis advisor: Michael Russell / The growth of computer-based testing over the last two decades has motivated the creation of innovative item formats. It is often argued that technology-enhanced items (TEIs) provide better measurement of test-takers’ knowledge, skills, and abilities by increasing the authenticity of tasks presented to test-takers (Sireci & Zenisky, 2006). Despite the popularity of TEIs in operational assessments, there remains little psychometric research on these innovative item formats. Claims regarding their potential to provide better measurement are seldomly explored. This dissertation adds to this limited body of research by developing theory and proposing a methodology to compare TEIs to traditional item formats. This study investigated how to judge the comparative measurement value (CMV) of two drag-and-drop technology-enhanced formats (classification and rank-ordering) relative to stem-equivalent multiple-choice items. Items were administered to a sample of adults and results were calibrated using a 2-parameter logistic IRT model. Moreover, the utility of the TEIs was evaluated according to the TEI Utility Framework (Russell, 2016). Four indicators were identified as the most valuable characteristics to judge CMV and then combined into a hierarchical decision protocol. When applied, this protocol provides a CMV judgment and a recommendation of the preferred item format. Applying the protocol to the items revealed that most TEIs examined in this study showed decreased CMV, indicating that in a real-life scenario the multiple-choice format would be favored for most of these item pairs. Recommendations for the use of the CMV protocol and directions of future related research are discussed. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Lynch School of Education. / Discipline: Educational Research, Measurement and Evaluation.

The phase-out of ozone-depleting refrigerants, such as R-12 and R-22, according to the Montreal Protocol of 1987, has provided the incentive to increase the thermal efficiency of current heating and refrigeration systems. The purpose of this study was to increase the accuracy of the predictions of both the heat transfer and pressure drop correlations for condensing refrigerants in the Intermittent flow regime. This was done utilizing a novel method involving the temporal and spectral analysis of the light intensity of the local flow regime, as seen through a sight glass. An experimental setup was designed, built and commissioned specifically for this purpose using refrigerant R-22 and a smooth tube. It was found that the accuracy of the mean heat transfer coefficient predictions increased substantially compared to other leading correlations,particularly at low mass fluxes. In terms of the pressure drop,the predictions also increased in accuracy, and it was found that the time fraction method allows for continuous predictions over flow regime transitions when using local flow-pattern-based pressure drop models. This was previously not possible. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

Die in dieser Arbeit vorgestellten Simulationen aufsteigender fluider Partikel wurden mit dem CFD-Programm FS3D durchgeführt, welches auf der Volume-of-Fluid (VoF) Methode basiert. Die Validierung des Codes erfolgt durch Vergleich der numerischen Lösungen für schleichende Strömungen mit analytischen Lösungen, wobei eine gute Übereinstimmung festgestellt wird. Im ersten Teil der Dissertation werden Simulationen für den freien Aufstieg von Öltropfen in Wasser mit experimentellen Beobachtungen hinsichtlich der Aufstiegsgeschwindigkeit, der Tropfenform und der Bewegungsbahn verglichen. Die Aufstiegsgeschwindigkeiten und Widerstandsbeiwerte sind vergleichbar, die simulierten Tropfen sind jedoch deutlich flacher. Dieser Unterschied kann durch Verunreinigungen der Grenzfläche im Experiment verursacht sein. Der Übergang von einem gradlinigen Aufstieg zu zickzack-förmigen Aufstiegsbahnen kann mit Hilfe der Simulationen auf Instabilitäten im Nachlauf der Blasen zurückgeführt werden, die zu einer periodischen Wirbelablösung führen. Im zweiten Teil der Dissertation wird der Aufstieg von Blasen in linearen Scherströmungen untersucht. Steigen die Blasen in einer vertikalen Scherströmung auf, so beobachtet man eine seitliche Migration. Diese seitliche Migration der Blasen wird durch die sogenannte Liftkraft verursacht, deren Vorzeichen und Betrag von der Blasengröße und den Stoffeigenschaften der Flüssigkeit abhängt. Die Simulationen zeigen, daß das Vorzeichen der Liftkraft für eher sphärische Blasen durch den Bernoulli-Effekt erklärt werden kann. An stark deformierten Blasen hingegen wirkt die Liftkraft in umgekehrter Richtung. Dieses Phänomen tritt auch in den Simulationen auf. Verschiedene Hypothesen für die Ursache dieses Phänomens werden überprüft. Die bekannteste experimentelle Korrelation für die Liftkraft von Tomiyama u.a. (2002) wird durch Simulation von realen Flüssigkeiten mit bekannten Stoffeigenschaften wie auch von Modellfluiden mit willkürlichen Stoffeigenschaften validiert und weitgehend bestätigt. Die Lift-Korrelation hat demnach hinsichtlich der Stoffeigenschaften der Flüssigkeit einen größeren Geltungsbereich, als bisher experimentell überprüft wurde. The simulations presented in this thesis were performed with the CFD code FS3D which is based on the Volume of Fluid method. The code is validated using analytical solutions for creeping flows and a good agreement is observed between simulation and analytical solution. In the first part of the thesis, the free rise of oil drops in water is simulated and compared with experimental observations. The results show that the rising velocities and the drag coefficients are similar in both cases, but the simulated drops are flatter (more oblate). This difference may be caused by impurities of the particle surface (surfactants) in the experiments. The simulations show that the transition from rectilinear to periodic trajectories is caused by instabilities in the wake, which lead to a periodic vortex shedding. In the second part of the thesis, the rise of bubbles in linear shear flows is investigated. If bubbles rise in a vertical shear flow, a lateral migration can be observed. This migration is caused by the so called lift force. Sign and magnitude of the lift force depend on the size of the bubble and the material properties of the liquid. The simulation results show that the sign of the lift force on spherical bubbles can be explained by the Bernoulli effect. However, the lift force on more distorted bubbles acts in the opposite direction. This phenomenon can also be observed in the simulation. In this work several hypotheses for the reason of this phenomenon are checked. Furthermore, most common correlation for the lift force (developed by Tomiyama et al. in 2002) is validated for fluids of known material and model fluids with arbitrary material data. The correlation is valid in a wider range of fluid material properties than proved experimentally up to now.

Das Ziel dieser Arbeit ist es, Methoden zur schnelleren Erstellung und Speicherung von Teilsichten prozessierter X3D-Dateien zu entwickeln. Point and Click und Drag and Drop werden als Interaktionsmethoden zur Erstellung der Teilsichten vorgestellt und anhand bestehender, wissenschaftlicher Studien verglichen. Drag and Drop wird als die günstigere Methode umgesetzt. Die Implementierung ermöglicht sowohl das Ziehen von Einträgen der integrierten Listenansicht als auch der Fragmente der Visualisierung.:Abbildungsverzeichnis Quellcode-Listings Abkürzungsverzeichnis 1 Einleitung 1.1 Motivation 1.2 Zielstellung 1.3 Aufbau der Arbeit 2 Stand der Forschung 2.1 Grundlagen der Softwarevisualisierung 2.1.1 Einordnung 2.1.2 Definition 2.1.3 Aufgaben 2.1.4 Metaphern 2.1.5 Generierung einer Softwarevisualisierung 2.2 Darstellung der Softwarevisualisierung und Interaktion 2.2.1 Die Oberfläche 2.2.2 Die Recursive Disc Metaphor 3 Technische Grundlagen 3.1 HTML5 3.2 JavaScript 3.3 Drag and Drop 3.4 Point and Click 3.5 Verwaltung der Struktur der Visualisierung durch zTree 4 Erzeugung von Teilsichten 4.1 Definition einer Teilsicht 4.2 Vergleich von Drag and Drop und Point and Click 4.3 Implementierung für den Package Explorer 4.4 Implementierung für die Visualisierung 5 Speichern und Laden von Teilsichten 5.1 Grundlagen zur Implementierung 5.2 Speichern einer Teilsicht 5.3 Laden einer Teilsicht 6 Fazit und Ausblick Literaturverzeichnis

A decline in high school dropout rates of students with learning disabilities (SWLDs) has been reported in the U.S. Virgin Islands (USVI). Of the2 school districts in the USVI, St. STT/STJ and STX, the researcher examined high school experiences of SWLDs who dropped out and did not attain a high school diploma in STX. Utilizing the conceptual framework of Maslow's hierarchy of needs, participants' personal high school experiences were examined in an effort to understand factors leading to their choice to drop out. The researcher interviewed 12 participants who were drop out SWLDs, ages 18 years and older. Interview data were coded and analyzed for common themes. Member checking and peer debriefing were utilized to achieve credibility and trustworthiness. Data analysis resulted in the identification of patterns, or themes, relative to participants' STX high school experiences which contributed to their decisions to drop out. The themes included, peer, family and teacher lack of support, ridicule, peer pressure and behavior problems. Most of the participants had not reached Maslow's highest need for self-actualization. Maslow purported that if needs are not being fulfilled in homes, then they can be fulfilled in schools where a positive school culture is apparent. In this case, students with learning disabilities needed to feel there was value in their education and obtaining a high school diploma. The results of this research might contribute to positive social change by identifying SWLDs' need requirements to attain a high school diploma and provide high school administrators with valuable information to enhance school learning environments for SWLDs and increase high school SWLD graduation rates.

Orientador: Roberto de Oliveira Roça / Resumo: Esse estudo objetivou avaliar a eficiência de estímulos elétricos com tensões crescentes durante a estimulação de meias carcaças no final do abate na qualidade do contrafilé até 28 dias de maturação. Metade das meias carcaças esquerdas de 40 novilhos Nelore (Bos taurus indicus), não castrados, com predomínio de cobertura de gordura mediana, foram submetidas ao Protocolo A (20, 40, 60 e 80 VRMS) e a outra metade foi submetida ao Protocolo B (50 VRMS). Ambos os protocolos com 12,5 Hz durante 52 segundos. As respectivas meias carcaças direitas não foram estimuladas (Controle A e Controle B). O pH e a temperatura das meias carcaças foram monitorados durante as 40 horas de resfriamento (1, 3, 6, 9, 12, 24 e 40 horas) e os respectivos contrafilés foram maturados por 2, 7, 14, 21 e 28 dias post-mortem. As duas combinações de estimulação elétrica de média voltagem aceleraram a taxa de declínio do pH (refletido na temperatura e no tempo que o pH cai para 6), resultando em valores médios para força de cisalhamento de 4,66 kgf pra o Protocolo A e 4,62 kg para o Protocolo B com diferença entre seus controles os quais apresentaram 5,36 kg e 5,29 kg respectivamente, mantendo essa característica durante a maturação. O comprimento dos sarcômeros não foi diferente (P>0,05) entre os protocolos e seus controles. O uso da estimulação elétrica com tensões crescentes não resultou em melhores características qualitativas da carne em relação a estimulação elétrica de tensão contínua. A força da esti... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study was aimed to evaluate the efficiency of electrical stimulation with increasing voltage during the stimulation of bovine half carcasses on the quality of 28 days aged strip loins. Half of the left half carcasses from 40 Nellore steers (Bos taurus indicus), intact, from the same feedlot, with median fat coverage, were submitted to Protocol A (20, 40, 60 and 80 VRMS) and the other half to Protocol B (50 VRMS). Both protocols with 12.5 Hz for 52 seconds. The respective right half carcasses were not stimulated (Control A and Control B). The pH and temperature were monitored during 40 hours of cooling (1, 3, 6, 9, 12, 24 and 40 hours) and the strip loins were aged for 2, 7, 14, 21, and 28 days post-mortem. Both combinations of medium voltage electrical stimulation accelerated the pH decline rate (reflected in temperature and the time that pH drop to 6), resulting in lower values for shear force 4.66 kgf for Protocol A, and 4.62 for Protocol B, with 5.36 kgf and 5,29 kgf for its respectively controls, maintaining this characteristic during aging time. The length of the sarcomere was not different (P>0.05) between the protocols and their controls. The use of an electrical stimulation with increasing tensions did not result in better qualitative characteristics of the meat in comparison to the continuous tension electrical stimulation. The strength of the electrical stimulation, the visual contractions, and the pH difference area (∆pH) did not have a proportional effect on ... (Complete abstract click electronic access below) / Mestre

This study was conducted to analyze the performance differences between alternative education campuses in Texas that used teacher-directed strategies and those that used self-directed strategies. The study was also conducted to inform educators of the results these two strategies had achieved with at-risk students during the three years of 2006-2008. The study used the results from the Texas Assessment of Knowledge and Skills test as reported in the AEIS annual reports from the Texas Education Agency. Alternative education schools were grouped according to the strategy used to educate at-risk students. The results of the statistical tests showed the two strategies had similar performance results and there was no statistical difference between the two. The results offered several implications concerning the ability of at-risk students to achieve in alternative education schools including possible reasons why students who were previously unsuccessful became successful in alternative settings. The report also addressed the number of students who continued to be unsuccessful even when placed on an alternative education campus. Possible reasons for this continued inability to succeed are discussed. Recommendations for further research were listed at the conclusion of the study.

Video files found in Chapter 5. : AUTOMATED OBJECT TRACKING, EVENT DETECTION AND RECOGNITION FOR HIGH-SPEED VIDEO OF DROP FORMATION PHENOMENA.<div><br></div><div>Video files found in APPENDIX E. CHAPTER 5, RESOURCE 2.</div>

<div>In this study, three ducts have been built in Herrick Labs, Purdue University, West Lafayette, representing the real HVAC systems. Different types of filters have been tested in each duct, including MERV8, MERV14 mechanical filters, and MERV13 electret filter. One of this study's main objectives is to compare in-situ filter performance with the MERV rating, which comes from laboratory testing. Eventually, we can explain the variations and have a better understanding of the in-situ filter performance. Another primary objective is to evaluate the aging process of tested filters. Typically, HVAC filters will not be replaced or maintained frequently, so they tend to stay in HVAC systems for an extended period. In this study, the evolution of filter aging performance is tested continuously for the experiment's entire duration, including temporal evolution of pressure drops, filtration efficiencies, and loaded particulate mass on the filter media.</div><div><br></div><div>This study will continue for 52 full weeks. This thesis is a part of the on-going study, including the data up to the first 18 weeks so far. As a result, the pressure drops are steadily increasing over time for most filters due to the natural filter loading process, except for the MERV13 electret filter, which shows no significant change at all. In terms of the filtration efficiencies, two efficiency categories are included: mass-based efficiencies (ePM x ) for sizeintegrated particulate mass (PM) and size-resolved efficiencies. It can be seen that there is no significant change in ePM x for MERV8 and MERV14 filters, MERV13 electret filter whereas shows a degradation in ePM x efficiencies. Size-resolve efficiencies provide additional filtration efficiencies as a function of particle sizes, therefore more comprehensive. It can be found that for MERV8 and MERV14 filters, the efficiencies are slowly increasing for particles above 300 nm, with some variations. MERV13 electret filter has an explicitly decreasing trend for efficiencies across all particle size ranges.</div><div><br></div><div>Besides the filter loading process, another component affecting the filter performance is the environmental factor, such as temperature, relative humidity (RH), and precipitation events, including rainfall and snowfall. As a result, it can be observed that when precipitation events, the pressure drops trend to decrease for that period. It is also evident that decreasing temperature tends to promote pressure drops.</div>

Thermographic phosphors are useful compounds to determine temperature, due to their luminescence characteristics being a function of temperature. In this research, Zinc Oxide: Gallium was evaluated for its ability to measure the temperature of an impact event in a drop weight apparatus. Different solids loadings of the phosphor were placed in a sylgard binder and these samples were then excited by a 355 nm laser as they were impacted. Images of the event were captured through two separate filters with a high-speed camera, from which intensity ratios were formed. These intensity ratios correlated to a temperature, revealing the change in temperature of the sample throughout the impact. Initial testing at a repetition rate of 500 kHz provided insignificant data, due to difficulties with timing. The whole impact event was not able to be captured, and the imprecise timing of the drop did not allow for imaging of a specific area of the impact. Moving to a slower repetition rate of 50 kHz, the entire impact was captured on the high-speed camera, showing three separate areas of interest. The first section of this area was where the impact was first initiated, resulting in a temperature increase. Next, there was a temperature decrease, where the energy from the drop weight transitioned to deforming, rather than heating the sample. Lastly, there was a final temperature rise when the sample was fully compressed, but the impact was still occurring. This trend presented itself in all of the samples, supporting the idea that when combined with the intensity ratio method, ZnO:Ga embedded in a sylgard binder is an appropriate method to determine the temperature changes in a high-speed impact event.