Structure-property quantification of an A36 steel alloy was the focus of this study in order to calibrate and validate a plasticity-damage model. The microstructural parameters included grain size, particle size, particle number density, particle nearest neighbor distances, and percent of ferrite and pearlite. The mechanical property data focused on stress-strain behavior under different applied strain rates (0.001/s, 0.1/s, and 1000/s), different temperatures (293 K and 573 K), and different stress states (compression, tension, and torsion). Notch tension tests were also conducted to validate the plasticity-damage model. Also, failure of an A36 I-beam was examined in cyclic loads, and the crack growth rates were quantified in terms of fatigue striation data. Dynamic strain aging was observed in the stress-strain behavior giving rise to an important point that there exists a critical temperature for such behavior.

Maintaining dissolved oxygen concentrations under different operating schemes (constant, manual or automated aeration control) was evaluated in 20 earthen catfish ponds ranging from 0.04 to 0.07 hectares in size. Ponds were assigned to treatments based on achieving equal distribution of biomass among treatments. Catfish weighing approximately 0.11 kg each were stocked at a rate of 14,820 catfish/hectare and were fed, to satiation, a 36% crude protein floating feed for the first week and switched to a 32% crude protein floating feed for the remainder of the study. Percentage weight gain, FCR and survival were calculated but did not differ among treatments. A partial enterprise budget analysis was generated to determine comparative value of different aeration techniques relative to production costs. Mean partial net returns did not differ among treatments. Complete comparison was not possible due to failure of automated monitors to record DO and to operate aerators under designed protocols.

ABSTRACT Alliaria petiolata (garlic mustard) is an aggressive non-native and invasive forb that negatively impacts native arbuscular mycorrhizal communities and inhibits or prevents the growth of native plant species. Invasive species mitigation and management strategies that use native revegetation vary in success. This study focuses on which species naturally regenerate in areas where A. petiolata has been mitigated to help inform restoration efforts. Seedling emergence of species within the seed bank of four plot types (uninvaded, invaded, chemically treated, and mechanically treated) were observed two years post restoration efforts to determine which native species are likely to persist to seedlings following management. Species abundance and percent cover of all plant species were recorded to evaluate the presence of species in addition to plant health and physiological differences. Native species abundance was significantly reduced within herbicide treated plots as compared to untreated and invaded plots (p=0.02). Plots treated with mechanical removal had the greatest percent cover of native plants as compared to all other plot types but were dominated by colonizing species which is typical of a disturbed habitat. Mechanical removal also resulted in a greater abundance and stability among functional groups of native species, than those treated with herbicide. Forb species dominated coverage of plots over other functional groups when treated with herbicide. Alliaria petiolata invasion and management methods significantly impacted forb and graminoid species, as they had significantly lower abundance in plots treated with herbicide. The results demonstrate that the method of removal as well as the presence of A. petiolata affects emergence of plant species from the seedbank. The additional disturbance of mechanical removal may alter successional trajectories following invasion. Herbicide treatment resulted in the most similar species abundance as the uninvaded reference plots, which had the lowest seedling emergence and percent cover.

<p>The main focus of this work is to improve the existing clinical machine model within the Pinnacle software planning system (at Juravinski Cancer Center, Hamilton, CA). The incident energy fluence spectrum exiting from the accelerator head is considered an important element of the machine model. Relying on the Pinnacle auto modeling function to determine the relative photon fluence spectrum based on percent depth dose curves fitting for various filed sizes, led to different solutions when the process cycle were repeated. This work presents a new method for determining the Pinnacle photon energy fluence spectrum based on 6 MV Varian 21EX machine. A Monte Carlo simulation spectrum based on BEAMnrc code was attenuated to various depths of water. We determine that, the BEAMnrc spectrum attenuated by 15 cm of water gives the closest agreement between the computed and measured depth dose, similar to the clinical machine spectrum.</p> <p>Implementing the novel spectrum into a machine that retained the same modeling parameters as the clinical machine (21ex-JCC) shows a slight better calculation of the output factor. The MLC model parameters were also investigated, however, adjusting the MLC offset table was found to give significant improvements, especially for the small field geometries.</p> <p>The full impact of adjusting the photon energy spectrum, Off-Axis Softening Factor, MLC rounded leaf tip radius and MLC calibration offsets were investigated individually, resulting in a good model parameter fit. Several proposed supplementary setups were created to further assess our model. This include a geometry sensitive to MLC abutment leakage, the calculation of output factors for long and narrow MLC defined fields, and small square MLC and jaws defined fields. A Sun-Point diode detector was used in the measurement of the output factors for its accurate precision at small geometries. In addition, a GAFCHROMIC EBT2 film dosimetry was used in the measurement of the MLC abutment leakage.</p> <p>Our new model shows superior results in comparison to the clinical 21ex-JCC machine model, especially with MLC small field calculations. We conclude that relying on PDD curves and dose profiles validation method in assessing the model might not necessarily lead to the best machine parameters, since these are not sensitive to subtle changes in parameters that have important dosimetric consequences.</p> / Master of Science (MSc)

This thesis is a study into the response and seismic safety of three-dimensional multi-storey concrete structures under concurrent orthogonal seismic excitations. It employs the nonlinear time-history method as its analysis tools. Time-history analyses rely heavily on their utilised earthquake records. Accordingly, this study examines the different approaches of selecting earthquake suites and develops a methodology of selecting representative earthquake scenarios. This methodology is credibly implemented in selecting a far- and a near field suites representative of the New Zealand seismic hazard. The study investigates the response of 6-, 9- and 12-storey concrete structures of different n-X-bays × m-Y-bays. Bidirectional responses of these considered structures are examined and consequently the current combination rules are scrutinised. Consequently this study strongly recommends the use of the 40-percent combination rule in lieu of the widely used 30-percent rule; and the use of time-history analysis in lieu of quasi/equivalent static and response modal analysis methods to avoid their strong dependence on combination rules. An intensive study is conducted employing the incremental dynamic analysis (IDA) technique to investigate structural demands of interstorey drifts, lateral storey drifts and storey accelerations. The study utilises the developed far-field suite and identifies the 50th and 90th percentile demands. Hence it provides easy-to-use expressions to facilitate rapid calculation of the structural demands and the effects of biaxial interactions. An implementation into the Demand and Capacity Factor Design (DCFD) format is presented that infers confidence in the performance levels of the considered structures. The study also draws attention to the importance of considering storey accelerations as their storey values reach as high as 10 × PGA. A sensitivity study is conducted by repeating the IDA investigation while using the developed near-field suite. Subsequently a comparison between the near- and the far-field results is conducted. The results were markedly similar albeit of less magnitudes until the (seismic hazard) intensity measure IM = Sa(T₁) = 0.4g when the near-field results show sudden flat large increase in demands suggesting a brittle collapse. This is attributed to the higher content of the higher mode frequencies contained in near-field ground motions. Finally, the study examines the (vectorial) radial horizontal shear demands in columns and beam-column joints of the previous far- and near-field studies. The combined radial shear demands in corner, edge and internal columns and joints are evaluated that roughly show a square-root proportional relationship with IM that exhibit somewhat brittle failure at IM ≥ 0.35g. Shears demands in the (4-way) internal columns and the (2-way) corner joints show highest magnitude in their respective class. The results suggest transverse joint shear reinforcement of 1.5, 1.0 and 0.5 of the longitudinal reinforcement of the neighbouring beam respectively for corner, edge and internal joints. An implementation of a proposed practical (and simpler) DCFD format shows satisfactory confidence in columns performance in shear up to IM = 0.35g, conversely to joints unsatisfactory performance in shear at the onset of inelastic behaviour (IM > 0.05g).

The creation of an instructional genius hour framework for classroom implementation is an objective of this study. Currently, genius hour educators use a wide variety of frameworks. Some genius hour educators do not follow a set framework, yet others continually modify their genius hour frameworks. This study draws attention to the need to create an instructional framework for classroom implementation. This study was conducted through semi-structured interviews with five of the most respected genius hour educators. For the purposes of this study, each individual educator was treated as a separate case study. During the semi-structured interviews, genius hour educators shared their personal experience with implementing genius hour, their personal philosophies and ideas related to genius hour, their recommendations regarding genius hour implementation, and their recommendations regarding genius hour frameworks for classroom implementation. Moreover, this study also conducted two observations of genius hour classrooms in action. These classroom observations offered data related to genius hour educational philosophy and the need for a genius hour framework. This study recommends that educators use an instructional framework when implementing genius hour. A framework will have a positive effect on the performance of genius hour because of the added structure and clarity it provides for students and educators. It is recommended that educators choose a framework, and modify it in order to best serve the academic needs of their particular genius hour programme. This study moves beyond the genius hour framework by identifying major themes that genius hour educators should consider when implementing genius hour in the classrooms. Alongside the importance of the framework model, the common themes of front-loading, learning from failure, developing passion, and mentoring emerged from the interviews and observations. In essence, this study developed a framework model, game time, based around the importance of incorporating the aforementioned themes. The findings within this study offer an understanding of the importance of using a genius hour framework for classroom implementation. This study envisions that educators can use the research gathered in order to create an optimal genius hour framework for classroom implementation. This offers a framework for classroom implementation, which should be individualized in order to best suit the classroom specific needs. / Hierdie studie het die skepping van ʼn genie-uur-onderrigraamwerk vir klaskamer-implementering ten doel. Tans gebruik genie-uuropvoeders ’n wye verskeidenheid raamwerke. Sommige genie-uuropvoeders volg nie ’n vasgestelde raamwerk nie, terwyl andere voortdurend hul genie-uurraamwerke verander. Hierdie studie vestig aandag op die behoefte om ʼn onderrigraamwerk vir klaskamerimplementering te skep. Hierdie studie is uitgevoer deur middel van halfgestruktureerde onderhoude met vyf van die mees gerespekteerde genie-uuropvoeders. Vir die doeleindes van hierdie studie is elke individuele opvoeder as ’n afsonderlike gevallestudie behandel. Gedurende die halfgestruktureerde onderhoude het genie-uuropvoeders hul persoonlike ervarings van die inwerkingstelling van genie-uur, hul persoonlike filosofieë en idees oor genie-uur, hul aanbevelings vir genie-uurimplementering, en hul aanbevelings vir genie-uurraamwerke vir klaskamerimplementering gedeel. Verder het hierdie stude ook twee waarnemings van genie-uurklaskamers-in-aksie uitgevoer. Hierdie klaskamerwaarnemings het data in verband met genie-uuronderwysfilosofie en die behoefte aan ’n genie-uurraamwerk opgelewer. Hierdie studie beveel aan dat opvoeders ʼn onderrigraamwerk gebruik wanneer hulle genie-uur in werking stel. ’n Raamwerk sal ’n positiewe uitwerking op die uitvoering van genie-uur hê as gevolg van die bykomende struktuur en duidelikheid wat dit aan studente en opvoeders bied. Daar word aanbeveel dat opvoeders ’n raamwerk kies en dit aanpas ten einde die beste in die akademiese behoeftes van hul betrokke genie-uurprogram te voorsien. Hierdie studie beweeg verder as die genie-uurraamwerk deur belangrike temas te identifiseer wat genie-uuropvoeders kan oorweeg wanneer hulle genie-uur in die klaskamers in werking stel. Afgesien van die belangrikheid van die raamwerkmodel het die algemene temas van voorkantlading, leer uit mislukking, ontwikkeling van passie en leidinggewing uit die onderhoude en waarnemings na vore gekom. Hierdie studie het wesenlik ’n raamwerkmodel ontwikkel, genaamd speeltyd, wat gebaseer is op die belangrikheid daarvan om die voorgenoemde temas te inkorporeer. Die bevindings van hierdie studie bied ʼn begrip van die belangrikheid daarvan om ’n genie-uurraamwerk vir klaskamerimplementering te gebruik. Hierdie studie stel in die vooruitsig dat opvoeders die navorsing sal gebruik wat ingesamel is om ʼn optimale genie-uurraamwerk vir klaskamerimplementering te skep. Dit bied ’n raamwerk vir klaskamerimplementering, wat geïndividualiseer behoort te word om die beste in die spesifieke behoeftes van elke klaskamer te voorsien. / Ukwakhiwa kohlaka lokufundisa ngendlela ye-genius hour oluzosetshenziswa ekilasini yiyona njongo yalolu cwaningo. Njengamanje, othisha abalandela indlela yegenius hour basebenzisa izinhlobonhlobo zezinhlaka. Abanye othisha abalandela indlela yegenius hour abasebenzisi izinhlaka ezibekiwe, kodwa abanye bayaqhubeka nokulungisa izinhlaka zabo zegenius hour. Lolu cwaningo luveza isidingo sokwakhiwa kohlaka lokufundisa oluzosetshenziswa ekilasini. Lolu cwaningo lwaluqhutshwa ngokuxoxisana okuhleliwe nothisha abahlanu abahlonishwa kakhulu begenius hour. Ngokwenjongo yalolu cwaningo, uthisha ngamunye wayethathwa njengowahlukile kwabanye abasetshenziswe ocwaningweni. Ngenkathi kuqhubeka izingxoxo ezihleliwe, othisha begenius hour baxoxa ngabahlangabezana nakho uma beqalisa ukusebenzisa igenius hour, imigomo abayilandelayo kanye namasu ahambisana negenius hour, izincomo zabo mayelana negenius hour kanye nezincomo zabo ngezinhlaka zegenius hour ezizosetshenziswa ekilasini. Phezu kwalokho, lolu cwaningo luphinde lwabuka kusetshenziswa igenius hour kabili emakilasini ngenkathi eqhubeka. Lokhu kubhekwa kwamakilasi kwaveza imininingwane eqondene nemigomo yezemfundo yegenius hour kanye nesidingo sohlaka lwegenius hour. Lolu cwaningo luncoma ukuba othisha basebenzise uhlaka lokufundisa uma beqala ukusebenzisa igenius hour. Uhlaka luzoba nomphumela omuhle ekusebenzeni kwegenius hour, ngenxa yokwakheka okwengeziwe kanye nokucacisa, ihlinzekela abafundi nothisha. Kunconywa ukuba othisha bakhethe uhlaka, balulungise kahle ukuze luhambisane nezidingo zezemfundo zohlelo lwabo oluthile lwegenius hour. Lolu cwaningo luhamba ludlulele ngale kohlaka lwegenius hour ngokuhlonza izingqikithi okufanele othisha begenius hour bacabange ngazo uma beqala ukusebenzisa igenius hour emakilasini. Ngaphandle kokubaluleka kwesimo sohlaka, izingqikithi ezejwayelekile zokufundisa ngokuhlahla indlela, ukufunda ngokwehluleka kuqala, ukukhula kothando kanye nokwalusa kwavela ezingxoxweni nasekubukeni. Empeleni. lolu cwaningo selwakhe isimo sohlaka, isikhathi semidlalo, okuncike ekubalulekeni kokuhlanganisa lezi zingqikithi ezibaliwe. Okutholakele kulolu cwaningo kunikeza ukuqonda kokubaluleka kokusebenzisa uhlaka lwegenius hour ekilasini. Lolu cwaningo lubona ukuthi othisha bangasebenzisa imininingwane etholakale ocwaningweni ukwakha uhlaka lwegenius hour olusebenza kahle oluzosetshenziswa ekilasini. Lokhu kuhlinzeka uhlaka oluzosetshenziswa ekilasini, okumele lwenziwe lusebenzele umuntu ngamunye ukuze luhambisane kahle nezidingo zekilasi ngalinye. / Curriculum and Instructional Studies / D. Ed. (Curriculum and Instructional Studies)